diff --git a/-sfaHVFWBU8.txt b/-sfaHVFWBU8.txt new file mode 100644 index 0000000000000000000000000000000000000000..f3f36f45cfe7288252eb66d1071c5c02a51d1df2 --- /dev/null +++ b/-sfaHVFWBU8.txt @@ -0,0 +1,12755 @@ +align:start position:0% + +foreign + + align:start position:0% + + + + align:start position:0% + +so let's continue our discussion about + + align:start position:0% +so let's continue our discussion about + + + align:start position:0% +so let's continue our discussion about +spectral theory for self-adjoint compact + + align:start position:0% +spectral theory for self-adjoint compact + + + align:start position:0% +spectral theory for self-adjoint compact +operators so let me just briefly recall + + align:start position:0% +operators so let me just briefly recall + + + align:start position:0% +operators so let me just briefly recall +um + + align:start position:0% +um + + + align:start position:0% +um +the spectrum of a bounded operator which + + align:start position:0% +the spectrum of a bounded operator which + + + align:start position:0% +the spectrum of a bounded operator which +was supposed to be a generalization + + align:start position:0% +was supposed to be a generalization + + + align:start position:0% +was supposed to be a generalization +of the eigenvalues of a matrix so we + + align:start position:0% +of the eigenvalues of a matrix so we + + + align:start position:0% +of the eigenvalues of a matrix so we +defined + + align:start position:0% +defined + + + align:start position:0% +defined +the resolvance set of a to B + + align:start position:0% +the resolvance set of a to B + + + align:start position:0% +the resolvance set of a to B +those complex numbers such that + + align:start position:0% + + + + align:start position:0% + +a minus Lambda times the identity which + + align:start position:0% +a minus Lambda times the identity which + + + align:start position:0% +a minus Lambda times the identity which +I just write as a minus Lambda is an + + align:start position:0% +I just write as a minus Lambda is an + + + align:start position:0% +I just write as a minus Lambda is an +invertible uh + + align:start position:0% +invertible uh + + + align:start position:0% +invertible uh +bounded linear operator meaning it is + + align:start position:0% +bounded linear operator meaning it is + + + align:start position:0% +bounded linear operator meaning it is +um bijective and which by the open + + align:start position:0% +um bijective and which by the open + + + align:start position:0% +um bijective and which by the open +mapping theorem tells you that the + + align:start position:0% +mapping theorem tells you that the + + + align:start position:0% +mapping theorem tells you that the +inverse is also continuous + + align:start position:0% +inverse is also continuous + + + align:start position:0% +inverse is also continuous +um + + align:start position:0% + + + + align:start position:0% + +and the Spectrum + + align:start position:0% +and the Spectrum + + + align:start position:0% +and the Spectrum +of a is simply those Lambda so that a + + align:start position:0% +of a is simply those Lambda so that a + + + align:start position:0% +of a is simply those Lambda so that a +minus Lambda is not invertible so the + + align:start position:0% +minus Lambda is not invertible so the + + + align:start position:0% +minus Lambda is not invertible so the +complement + + align:start position:0% +complement + + + align:start position:0% +complement +of + + align:start position:0% + + + + align:start position:0% + +resolve instead of a + + align:start position:0% +resolve instead of a + + + align:start position:0% +resolve instead of a +okay and so + + align:start position:0% +okay and so + + + align:start position:0% +okay and so +you know from + + align:start position:0% + + + + align:start position:0% + +linear algebra + + align:start position:0% +linear algebra + + + align:start position:0% +linear algebra +you have the following uh + + align:start position:0% + + + + align:start position:0% + +characterization of what the spectrum is + + align:start position:0% +characterization of what the spectrum is + + + align:start position:0% +characterization of what the spectrum is +that uh + + align:start position:0% + + + + align:start position:0% + +if H is c n and a is just therefore a + + align:start position:0% +if H is c n and a is just therefore a + + + align:start position:0% +if H is c n and a is just therefore a +matrix on c n or RN if you like then the + + align:start position:0% +matrix on c n or RN if you like then the + + + align:start position:0% +matrix on c n or RN if you like then the +spectrum is just simply the set of + + align:start position:0% +spectrum is just simply the set of + + + align:start position:0% +spectrum is just simply the set of +eigenvalues + + align:start position:0% + + + + align:start position:0% + +of a + + align:start position:0% +of a + + + align:start position:0% +of a +okay and if we restrict our attention to + + align:start position:0% +okay and if we restrict our attention to + + + align:start position:0% +okay and if we restrict our attention to +hermitian matrices + + align:start position:0% +hermitian matrices + + + align:start position:0% +hermitian matrices +uh + + align:start position:0% +uh + + + align:start position:0% +uh +meaning which are referred to as which + + align:start position:0% +meaning which are referred to as which + + + align:start position:0% +meaning which are referred to as which +are also + + align:start position:0% +are also + + + align:start position:0% +are also +um + + align:start position:0% +um + + + align:start position:0% +um +referred to as self-adjoint also in in + + align:start position:0% +referred to as self-adjoint also in in + + + align:start position:0% +referred to as self-adjoint also in in +linear algebra or symmetric if we're + + align:start position:0% +linear algebra or symmetric if we're + + + align:start position:0% +linear algebra or symmetric if we're +just looking at + + align:start position:0% +just looking at + + + align:start position:0% +just looking at +um + + align:start position:0% +um + + + align:start position:0% +um +real Vector spaces are in + + align:start position:0% +real Vector spaces are in + + + align:start position:0% +real Vector spaces are in +um + + align:start position:0% +um + + + align:start position:0% +um +then the eigenvalues are real + + align:start position:0% +then the eigenvalues are real + + + align:start position:0% +then the eigenvalues are real +and you can find an orthonormal basis of + + align:start position:0% +and you can find an orthonormal basis of + + + align:start position:0% +and you can find an orthonormal basis of +the space CN or RN depending on what + + align:start position:0% +the space CN or RN depending on what + + + align:start position:0% +the space CN or RN depending on what +you're looking at + + align:start position:0% +you're looking at + + + align:start position:0% +you're looking at +for this + + align:start position:0% +for this + + + align:start position:0% +for this +symmetric Matrix so that a complete in + + align:start position:0% +symmetric Matrix so that a complete in + + + align:start position:0% +symmetric Matrix so that a complete in +that Matrix The Matrix in that basis The + + align:start position:0% +that Matrix The Matrix in that basis The + + + align:start position:0% +that Matrix The Matrix in that basis The +Matrix is completely diagonalized okay + + align:start position:0% +Matrix is completely diagonalized okay + + + align:start position:0% +Matrix is completely diagonalized okay +and what are the diagonal elements there + + align:start position:0% +and what are the diagonal elements there + + + align:start position:0% +and what are the diagonal elements there +the eigenvalues of the Matrix okay and + + align:start position:0% +the eigenvalues of the Matrix okay and + + + align:start position:0% +the eigenvalues of the Matrix okay and +what we're going to end up proving is + + align:start position:0% +what we're going to end up proving is + + + align:start position:0% +what we're going to end up proving is +that that picture this kind of picture + + align:start position:0% +that that picture this kind of picture + + + align:start position:0% +that that picture this kind of picture +where the + + align:start position:0% +where the + + + align:start position:0% +where the +um for a + + align:start position:0% +um for a + + + align:start position:0% +um for a +you know self-adjoined Matrix on CN that + + align:start position:0% +you know self-adjoined Matrix on CN that + + + align:start position:0% +you know self-adjoined Matrix on CN that +the spectrum is given by the eigenvalues + + align:start position:0% +the spectrum is given by the eigenvalues + + + align:start position:0% +the spectrum is given by the eigenvalues +and you can diagonalize essentially + + align:start position:0% +and you can diagonalize essentially + + + align:start position:0% +and you can diagonalize essentially +diagonalize this operator meaning you + + align:start position:0% +diagonalize this operator meaning you + + + align:start position:0% +diagonalize this operator meaning you +can form find a orthonormal basis + + align:start position:0% +can form find a orthonormal basis + + + align:start position:0% +can form find a orthonormal basis +consisting entirely of eigenvectors of + + align:start position:0% +consisting entirely of eigenvectors of + + + align:start position:0% +consisting entirely of eigenvectors of +the operator is also true for uh + + align:start position:0% +the operator is also true for uh + + + align:start position:0% +the operator is also true for uh +self-ajoint compact operators okay this + + align:start position:0% +self-ajoint compact operators okay this + + + align:start position:0% +self-ajoint compact operators okay this +shouldn't come too much of a surprise as + + align:start position:0% +shouldn't come too much of a surprise as + + + align:start position:0% +shouldn't come too much of a surprise as +too much of a surprise since compact + + align:start position:0% +too much of a surprise since compact + + + align:start position:0% +too much of a surprise since compact +operators are limits of finite rank I.E + + align:start position:0% +operators are limits of finite rank I.E + + + align:start position:0% +operators are limits of finite rank I.E +Matrix matrices uh + + align:start position:0% +Matrix matrices uh + + + align:start position:0% +Matrix matrices uh +um + + align:start position:0% +um + + + align:start position:0% +um +in the space of bounded linear operators + + align:start position:0% +in the space of bounded linear operators + + + align:start position:0% +in the space of bounded linear operators +okay so that's where we're headed + + align:start position:0% +okay so that's where we're headed + + + align:start position:0% +okay so that's where we're headed +um + + align:start position:0% +um + + + align:start position:0% +um +now + + align:start position:0% +now + + + align:start position:0% +now +so just to + + align:start position:0% +so just to + + + align:start position:0% +so just to +follow up on this + + align:start position:0% +follow up on this + + + align:start position:0% +follow up on this +and + + align:start position:0% +and + + + align:start position:0% +and +for a little bit of review so you know + + align:start position:0% +for a little bit of review so you know + + + align:start position:0% +for a little bit of review so you know +in the finite dimensional space in the + + align:start position:0% +in the finite dimensional space in the + + + align:start position:0% +in the finite dimensional space in the +finite dimensional case the Spectrum can + + align:start position:0% +finite dimensional case the Spectrum can + + + align:start position:0% +finite dimensional case the Spectrum can +be or the spectrum is always just the + + align:start position:0% +be or the spectrum is always just the + + + align:start position:0% +be or the spectrum is always just the +eigenvalues of the Matrix a not so in + + align:start position:0% +eigenvalues of the Matrix a not so in + + + align:start position:0% +eigenvalues of the Matrix a not so in +the infinite dimensional + + align:start position:0% +the infinite dimensional + + + align:start position:0% +the infinite dimensional +setting for example if we're looking at + + align:start position:0% +setting for example if we're looking at + + + align:start position:0% +setting for example if we're looking at +little L2 and then a + + align:start position:0% +little L2 and then a + + + align:start position:0% +little L2 and then a +times a is equal to let's say A1 over + + align:start position:0% +times a is equal to let's say A1 over + + + align:start position:0% +times a is equal to let's say A1 over +one a two over two + + align:start position:0% +one a two over two + + + align:start position:0% +one a two over two +and so on + + align:start position:0% +and so on + + + align:start position:0% +and so on +for a + + align:start position:0% +for a + + + align:start position:0% +for a +sequence in L2 then + + align:start position:0% +sequence in L2 then + + + align:start position:0% +sequence in L2 then +um + + align:start position:0% +um + + + align:start position:0% +um +which we can prove is that 0 is in + + align:start position:0% + + + + align:start position:0% + +the spectrum of a + + align:start position:0% +the spectrum of a + + + align:start position:0% +the spectrum of a +all right one way to see that is that uh + + align:start position:0% + + + + align:start position:0% + +each of the if you like basis vectors of + + align:start position:0% +each of the if you like basis vectors of + + + align:start position:0% +each of the if you like basis vectors of +H given where you just have one in the + + align:start position:0% +H given where you just have one in the + + + align:start position:0% +H given where you just have one in the +nth slot and 0 otherwise each of those + + align:start position:0% +nth slot and 0 otherwise each of those + + + align:start position:0% +nth slot and 0 otherwise each of those +is an eigenvector of this operator a + + align:start position:0% +is an eigenvector of this operator a + + + align:start position:0% +is an eigenvector of this operator a +with eigenvalue 1 over n where the N + + align:start position:0% +with eigenvalue 1 over n where the N + + + align:start position:0% +with eigenvalue 1 over n where the N +tells you where the one is and zero + + align:start position:0% +tells you where the one is and zero + + + align:start position:0% +tells you where the one is and zero +otherwise so 1 over n is in is an + + align:start position:0% +otherwise so 1 over n is in is an + + + align:start position:0% +otherwise so 1 over n is in is an +eigenvalue + + align:start position:0% +eigenvalue + + + align:start position:0% +eigenvalue +of this operator for each n + + align:start position:0% +of this operator for each n + + + align:start position:0% +of this operator for each n +and one over n converges to zero + + align:start position:0% +and one over n converges to zero + + + align:start position:0% +and one over n converges to zero +and since the spectrum of a bounded + + align:start position:0% +and since the spectrum of a bounded + + + align:start position:0% +and since the spectrum of a bounded +linear operator is a compact set in + + align:start position:0% +linear operator is a compact set in + + + align:start position:0% +linear operator is a compact set in +particular closed zero which is the + + align:start position:0% +particular closed zero which is the + + + align:start position:0% +particular closed zero which is the +limit of that sequence has to also be in + + align:start position:0% +limit of that sequence has to also be in + + + align:start position:0% +limit of that sequence has to also be in +the Spectrum + + align:start position:0% +the Spectrum + + + align:start position:0% +the Spectrum +okay and in fact what we're going to + + align:start position:0% +okay and in fact what we're going to + + + align:start position:0% +okay and in fact what we're going to +show is that you know kind of in the + + align:start position:0% +show is that you know kind of in the + + + align:start position:0% +show is that you know kind of in the +non-degenerate case what we see here is + + align:start position:0% +non-degenerate case what we see here is + + + align:start position:0% +non-degenerate case what we see here is +what in general happens for compact + + align:start position:0% +what in general happens for compact + + + align:start position:0% +what in general happens for compact +self-ajoint operators that + + align:start position:0% +self-ajoint operators that + + + align:start position:0% +self-ajoint operators that +um + + align:start position:0% +um + + + align:start position:0% +um +if it's not a finite rank operator then + + align:start position:0% +if it's not a finite rank operator then + + + align:start position:0% +if it's not a finite rank operator then +it has countably many + + align:start position:0% +it has countably many + + + align:start position:0% +it has countably many +uh accountably infinite many that's not + + align:start position:0% +uh accountably infinite many that's not + + + align:start position:0% +uh accountably infinite many that's not +a very good string of words accountably + + align:start position:0% +a very good string of words accountably + + + align:start position:0% +a very good string of words accountably +infinite eigenvalues which converge to + + align:start position:0% +infinite eigenvalues which converge to + + + align:start position:0% +infinite eigenvalues which converge to +zero okay and zero maybe an eigenvalue + + align:start position:0% +zero okay and zero maybe an eigenvalue + + + align:start position:0% +zero okay and zero maybe an eigenvalue +may not be okay + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% +and + + + align:start position:0% +and +um + + align:start position:0% +um + + + align:start position:0% +um +what's more that's going to be the only + + align:start position:0% +what's more that's going to be the only + + + align:start position:0% +what's more that's going to be the only +uh + + align:start position:0% + + + + align:start position:0% + +that completely characterizes the + + align:start position:0% +that completely characterizes the + + + align:start position:0% +that completely characterizes the +Spectrum so let me just write here for + + align:start position:0% +Spectrum so let me just write here for + + + align:start position:0% +Spectrum so let me just write here for +this example + + align:start position:0% +this example + + + align:start position:0% +this example +that in fact the spectrum of a is equal + + align:start position:0% +that in fact the spectrum of a is equal + + + align:start position:0% +that in fact the spectrum of a is equal +to + + align:start position:0% +to + + + align:start position:0% +to +0.0 Union + + align:start position:0% +0.0 Union + + + align:start position:0% +0.0 Union +1 over n + + align:start position:0% +1 over n + + + align:start position:0% +1 over n +in a natural number + + align:start position:0% +in a natural number + + + align:start position:0% +in a natural number +and these are again for this operator + + align:start position:0% +and these are again for this operator + + + align:start position:0% +and these are again for this operator +here these are the eigenvalues + + align:start position:0% +here these are the eigenvalues + + + align:start position:0% +here these are the eigenvalues +and this is just well zero is zero but + + align:start position:0% +and this is just well zero is zero but + + + align:start position:0% +and this is just well zero is zero but +zero is not + + align:start position:0% + + + + align:start position:0% + +an eigenvalue okay + + align:start position:0% + + + + align:start position:0% + +now this is not the general picture + + align:start position:0% +now this is not the general picture + + + align:start position:0% +now this is not the general picture +meaning that for a compact self-adjoin + + align:start position:0% +meaning that for a compact self-adjoin + + + align:start position:0% +meaning that for a compact self-adjoin +operator you'll have infinitely many + + align:start position:0% +operator you'll have infinitely many + + + align:start position:0% +operator you'll have infinitely many +eigenvalues and then zero will not be an + + align:start position:0% +eigenvalues and then zero will not be an + + + align:start position:0% +eigenvalues and then zero will not be an +eigenvalue you could have zero and + + align:start position:0% +eigenvalue you could have zero and + + + align:start position:0% +eigenvalue you could have zero and +eigenvalue as well but in general what + + align:start position:0% +eigenvalue as well but in general what + + + align:start position:0% +eigenvalue as well but in general what +the picture is is that anything in the + + align:start position:0% +the picture is is that anything in the + + + align:start position:0% +the picture is is that anything in the +Spectrum that's not zero has to be an + + align:start position:0% +Spectrum that's not zero has to be an + + + align:start position:0% +Spectrum that's not zero has to be an +eigenvalue + + align:start position:0% +eigenvalue + + + align:start position:0% +eigenvalue +okay and that's essentially what will + + align:start position:0% +okay and that's essentially what will + + + align:start position:0% +okay and that's essentially what will +prove + + align:start position:0% +prove + + + align:start position:0% +prove +our first result + + align:start position:0% + + + + align:start position:0% + +of + + align:start position:0% +of + + + align:start position:0% +of +this lecture is that is following so + + align:start position:0% + + + + align:start position:0% + +this is the Fred home + + align:start position:0% + + + + align:start position:0% + +alternative + + align:start position:0% + + + + align:start position:0% + +so let + + align:start position:0% + + + + align:start position:0% + +a b itself a joint compact operator + + align:start position:0% + + + + align:start position:0% + +and uh + + align:start position:0% + + + + align:start position:0% + +Lambda be a non-zero real number + + align:start position:0% + + + + align:start position:0% + +then + + align:start position:0% + + + + align:start position:0% + +the range of a minus Lambda + + align:start position:0% + + + + align:start position:0% + +is closed + + align:start position:0% +is closed + + + align:start position:0% +is closed +so this is the conclusion + + align:start position:0% + + + + align:start position:0% + +and thus + + align:start position:0% + + + + align:start position:0% + +the range of a minus Lambda is equal to + + align:start position:0% +the range of a minus Lambda is equal to + + + align:start position:0% +the range of a minus Lambda is equal to +the orthogonal complement of the + + align:start position:0% +the orthogonal complement of the + + + align:start position:0% +the orthogonal complement of the +orthogonal complement of itself + + align:start position:0% + + + + align:start position:0% + +which + + align:start position:0% + + + + align:start position:0% + +the orthogonal complement of the range + + align:start position:0% +the orthogonal complement of the range + + + align:start position:0% +the orthogonal complement of the range +of a minus Lambda is equal to the null + + align:start position:0% +of a minus Lambda is equal to the null + + + align:start position:0% +of a minus Lambda is equal to the null +space of the adjoint and since a is sulf + + align:start position:0% +space of the adjoint and since a is sulf + + + align:start position:0% +space of the adjoint and since a is sulf +a joint and Lambda is a real number the + + align:start position:0% +a joint and Lambda is a real number the + + + align:start position:0% +a joint and Lambda is a real number the +adjoint is just a minus Lambda + + align:start position:0% +adjoint is just a minus Lambda + + + align:start position:0% +adjoint is just a minus Lambda +okay so this right here is the + + align:start position:0% +okay so this right here is the + + + align:start position:0% +okay so this right here is the +main conclusion from which you get this + + align:start position:0% +main conclusion from which you get this + + + align:start position:0% +main conclusion from which you get this +and therefore + + align:start position:0% +and therefore + + + align:start position:0% +and therefore +just to spell out + + align:start position:0% +just to spell out + + + align:start position:0% +just to spell out +uh the conclusion of + + align:start position:0% +uh the conclusion of + + + align:start position:0% +uh the conclusion of +this equality therefore + + align:start position:0% + + + + align:start position:0% + +either uh + + align:start position:0% +either uh + + + align:start position:0% +either uh +one of two Alternatives happens so + + align:start position:0% +one of two Alternatives happens so + + + align:start position:0% +one of two Alternatives happens so +that's the name alternative either + + align:start position:0% +that's the name alternative either + + + align:start position:0% +that's the name alternative either +um + + align:start position:0% + + + + align:start position:0% + +a minus Lambda is + + align:start position:0% +a minus Lambda is + + + align:start position:0% +a minus Lambda is +by objective + + align:start position:0% + + + + align:start position:0% + +or + + align:start position:0% + + + + align:start position:0% + +the null space of a minus Lambda which + + align:start position:0% +the null space of a minus Lambda which + + + align:start position:0% +the null space of a minus Lambda which +is just the eigenspace of a minus Lambda + + align:start position:0% +is just the eigenspace of a minus Lambda + + + align:start position:0% +is just the eigenspace of a minus Lambda +or I should say the eigenspace + + align:start position:0% +or I should say the eigenspace + + + align:start position:0% +or I should say the eigenspace +corresponding to uh + + align:start position:0% + + + + align:start position:0% + +Lambda is + + align:start position:0% + + + + align:start position:0% + +non-trivial + + align:start position:0% +non-trivial + + + align:start position:0% +non-trivial +foreign + + align:start position:0% + + + + align:start position:0% + +and finite dimensional + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +moreover this equality here tells you + + align:start position:0% +moreover this equality here tells you + + + align:start position:0% +moreover this equality here tells you +when you can solve the equation a minus + + align:start position:0% +when you can solve the equation a minus + + + align:start position:0% +when you can solve the equation a minus +Lambda U equals F right + + align:start position:0% +Lambda U equals F right + + + align:start position:0% +Lambda U equals F right +you can solve a minus Lambda U equals F + + align:start position:0% +you can solve a minus Lambda U equals F + + + align:start position:0% +you can solve a minus Lambda U equals F +if and only if f is in the range of a + + align:start position:0% +if and only if f is in the range of a + + + align:start position:0% +if and only if f is in the range of a +minus Lambda which is if and only if f + + align:start position:0% +minus Lambda which is if and only if f + + + align:start position:0% +minus Lambda which is if and only if f +is orthogonal to the null space of a + + align:start position:0% +is orthogonal to the null space of a + + + align:start position:0% +is orthogonal to the null space of a +minus Lambda so let me make a little + + align:start position:0% +minus Lambda so let me make a little + + + align:start position:0% +minus Lambda so let me make a little +uh + + align:start position:0% +uh + + + align:start position:0% +uh +remark here so first off + + align:start position:0% +remark here so first off + + + align:start position:0% +remark here so first off +um the fact that this space has to be + + align:start position:0% +um the fact that this space has to be + + + align:start position:0% +um the fact that this space has to be +finite dimensional we proved last time + + align:start position:0% +finite dimensional we proved last time + + + align:start position:0% +finite dimensional we proved last time +right we proved at the end of uh + + align:start position:0% +right we proved at the end of uh + + + align:start position:0% +right we proved at the end of uh +um + + align:start position:0% +um + + + align:start position:0% +um +lecture the last lecture that for a + + align:start position:0% +lecture the last lecture that for a + + + align:start position:0% +lecture the last lecture that for a +compact self-adjoined operator + + align:start position:0% +compact self-adjoined operator + + + align:start position:0% +compact self-adjoined operator +the null space the eigenspace + + align:start position:0% +the null space the eigenspace + + + align:start position:0% +the null space the eigenspace +corresponding to a given non-zero + + align:start position:0% +corresponding to a given non-zero + + + align:start position:0% +corresponding to a given non-zero +eigenvalue + + align:start position:0% +eigenvalue + + + align:start position:0% +eigenvalue +is finite dimensional right and then we + + align:start position:0% +is finite dimensional right and then we + + + align:start position:0% +is finite dimensional right and then we +also proved the eigenspaces + + align:start position:0% +also proved the eigenspaces + + + align:start position:0% +also proved the eigenspaces +corresponding to two different + + align:start position:0% +corresponding to two different + + + align:start position:0% +corresponding to two different +eigenvalues or orthogonal and we also + + align:start position:0% +eigenvalues or orthogonal and we also + + + align:start position:0% +eigenvalues or orthogonal and we also +prove that the eigenvalues that are + + align:start position:0% +prove that the eigenvalues that are + + + align:start position:0% +prove that the eigenvalues that are +non-zero or any eigenvalue has to be + + align:start position:0% +non-zero or any eigenvalue has to be + + + align:start position:0% +non-zero or any eigenvalue has to be +real okay + + align:start position:0% + + + + align:start position:0% + +so now let me make a + + align:start position:0% + + + + align:start position:0% + +couple of remarks the first is just a + + align:start position:0% +couple of remarks the first is just a + + + align:start position:0% +couple of remarks the first is just a +rephrasing of what's in the theorem that + + align:start position:0% +rephrasing of what's in the theorem that + + + align:start position:0% +rephrasing of what's in the theorem that +therefore um + + align:start position:0% + + + + align:start position:0% + +f + + align:start position:0% +f + + + align:start position:0% +f +is in the range of a minus Lambda + + align:start position:0% +is in the range of a minus Lambda + + + align:start position:0% +is in the range of a minus Lambda +meaning you can solve the equation a + + align:start position:0% +meaning you can solve the equation a + + + align:start position:0% +meaning you can solve the equation a +minus Lambda U equals f + + align:start position:0% +minus Lambda U equals f + + + align:start position:0% +minus Lambda U equals f +if and only if + + align:start position:0% + + + + align:start position:0% + +f is in the null space of + + align:start position:0% +f is in the null space of + + + align:start position:0% +f is in the null space of +you're the orthogonal complement of a + + align:start position:0% +you're the orthogonal complement of a + + + align:start position:0% +you're the orthogonal complement of a +minus uh of the null space of a minus + + align:start position:0% +minus uh of the null space of a minus + + + align:start position:0% +minus uh of the null space of a minus +Lambda okay so what this says is that uh + + align:start position:0% +Lambda okay so what this says is that uh + + + align:start position:0% +Lambda okay so what this says is that uh +you can solve for f given that F + + align:start position:0% +you can solve for f given that F + + + align:start position:0% +you can solve for f given that F +satisfies finitely many uh linear + + align:start position:0% +satisfies finitely many uh linear + + + align:start position:0% +satisfies finitely many uh linear +conditions okay right because the null + + align:start position:0% +conditions okay right because the null + + + align:start position:0% +conditions okay right because the null +space of a minus Lambda is finite + + align:start position:0% +space of a minus Lambda is finite + + + align:start position:0% +space of a minus Lambda is finite +dimensional so F being orthogonal to + + align:start position:0% +dimensional so F being orthogonal to + + + align:start position:0% +dimensional so F being orthogonal to +that means pick a finite base a finite + + align:start position:0% +that means pick a finite base a finite + + + align:start position:0% +that means pick a finite base a finite +or orthonormal basis of a minus null + + align:start position:0% +or orthonormal basis of a minus null + + + align:start position:0% +or orthonormal basis of a minus null +space of a minus Lambda then F in a + + align:start position:0% +space of a minus Lambda then F in a + + + align:start position:0% +space of a minus Lambda then F in a +product with those finitely many vectors + + align:start position:0% +product with those finitely many vectors + + + align:start position:0% +product with those finitely many vectors +has to be zero so you have finitely many + + align:start position:0% +has to be zero so you have finitely many + + + align:start position:0% +has to be zero so you have finitely many +conditions on F to be able to solve for + + align:start position:0% +conditions on F to be able to solve for + + + align:start position:0% +conditions on F to be able to solve for +f and not only that this solution that + + align:start position:0% +f and not only that this solution that + + + align:start position:0% +f and not only that this solution that +you compute is also unique of two + + align:start position:0% +you compute is also unique of two + + + align:start position:0% +you compute is also unique of two +finitely many conditions because again + + align:start position:0% +finitely many conditions because again + + + align:start position:0% +finitely many conditions because again +the null space of a minus Lambda is + + align:start position:0% +the null space of a minus Lambda is + + + align:start position:0% +the null space of a minus Lambda is +um + + align:start position:0% +um + + + align:start position:0% +um +or unique up to a finite dimensional + + align:start position:0% +or unique up to a finite dimensional + + + align:start position:0% +or unique up to a finite dimensional +Subspace again because the null space of + + align:start position:0% +Subspace again because the null space of + + + align:start position:0% +Subspace again because the null space of +a minus Lambda is finite dimensional and + + align:start position:0% +a minus Lambda is finite dimensional and + + + align:start position:0% +a minus Lambda is finite dimensional and +the second is uh that uh + + align:start position:0% + + + + align:start position:0% + +since uh for a self-adjoint uh operator + + align:start position:0% +since uh for a self-adjoint uh operator + + + align:start position:0% +since uh for a self-adjoint uh operator +we have at + + align:start position:0% +we have at + + + align:start position:0% +we have at +the spectrum is + + align:start position:0% +the spectrum is + + + align:start position:0% +the spectrum is +a subset of the real numbers right for a + + align:start position:0% +a subset of the real numbers right for a + + + align:start position:0% +a subset of the real numbers right for a +self-adjoin operator this is something + + align:start position:0% +self-adjoin operator this is something + + + align:start position:0% +self-adjoin operator this is something +we proved uh last lecture it doesn't + + align:start position:0% +we proved uh last lecture it doesn't + + + align:start position:0% +we proved uh last lecture it doesn't +have to be compact just a self-adjoin + + align:start position:0% +have to be compact just a self-adjoin + + + align:start position:0% +have to be compact just a self-adjoin +operator so since the spectrum is a + + align:start position:0% +operator so since the spectrum is a + + + align:start position:0% +operator so since the spectrum is a +subset of the reals this proves that for + + align:start position:0% +subset of the reals this proves that for + + + align:start position:0% +subset of the reals this proves that for +a compact + + align:start position:0% +a compact + + + align:start position:0% +a compact +self-adjoin operator the spectrum of a + + align:start position:0% +self-adjoin operator the spectrum of a + + + align:start position:0% +self-adjoin operator the spectrum of a +is equal to the set of + + align:start position:0% + + + + align:start position:0% + +eigenvalues of a or I should say + + align:start position:0% +eigenvalues of a or I should say + + + align:start position:0% +eigenvalues of a or I should say +non-zero eigenvalues of a + + align:start position:0% + + + + align:start position:0% + +or let's let's let's write it this way + + align:start position:0% +or let's let's let's write it this way + + + align:start position:0% +or let's let's let's write it this way +if I look at what's in the spec Spectrum + + align:start position:0% +if I look at what's in the spec Spectrum + + + align:start position:0% +if I look at what's in the spec Spectrum +other than 0 possibly + + align:start position:0% +other than 0 possibly + + + align:start position:0% +other than 0 possibly +then the non-zero numbers that are in + + align:start position:0% +then the non-zero numbers that are in + + + align:start position:0% +then the non-zero numbers that are in +the Spectrum have to be eigenvalues + + align:start position:0% + + + + align:start position:0% + +okay so for a compact self-adjoint + + align:start position:0% +okay so for a compact self-adjoint + + + align:start position:0% +okay so for a compact self-adjoint +operator + + align:start position:0% +operator + + + align:start position:0% +operator +and adjusting the case of matrices the + + align:start position:0% +and adjusting the case of matrices the + + + align:start position:0% +and adjusting the case of matrices the +Spectrum + + align:start position:0% +Spectrum + + + align:start position:0% +Spectrum +the non-zero Spectrum has to be are + + align:start position:0% +the non-zero Spectrum has to be are + + + align:start position:0% +the non-zero Spectrum has to be are +nothing but eigenvalues okay and last + + align:start position:0% +nothing but eigenvalues okay and last + + + align:start position:0% +nothing but eigenvalues okay and last +time remember we proved that the + + align:start position:0% +time remember we proved that the + + + align:start position:0% +time remember we proved that the +eigenvalues are accountably infinite + + align:start position:0% +eigenvalues are accountably infinite + + + align:start position:0% +eigenvalues are accountably infinite +uh + + align:start position:0% +uh + + + align:start position:0% +uh +or countable they're either finite or + + align:start position:0% +or countable they're either finite or + + + align:start position:0% +or countable they're either finite or +countably infinite and if they're + + align:start position:0% +countably infinite and if they're + + + align:start position:0% +countably infinite and if they're +countably infinite they converge to zero + + align:start position:0% +countably infinite they converge to zero + + + align:start position:0% +countably infinite they converge to zero +okay + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +Again by last lecture + + align:start position:0% + + + + align:start position:0% + +we conclude again that + + align:start position:0% +we conclude again that + + + align:start position:0% +we conclude again that +uh + + align:start position:0% +uh + + + align:start position:0% +uh +the spectrum of a + + align:start position:0% +the spectrum of a + + + align:start position:0% +the spectrum of a +take away zero + + align:start position:0% +take away zero + + + align:start position:0% +take away zero +equals either + + align:start position:0% +equals either + + + align:start position:0% +equals either +finitely many + + align:start position:0% +finitely many + + + align:start position:0% +finitely many +eigenvalues + + align:start position:0% +eigenvalues + + + align:start position:0% +eigenvalues +or + + align:start position:0% + + + + align:start position:0% + +accountably infinite + + align:start position:0% +accountably infinite + + + align:start position:0% +accountably infinite +eigenvalues + + align:start position:0% + + + + align:start position:0% + +with that are converging to zero + + align:start position:0% + + + + align:start position:0% + +so from the Fred home alternative you + + align:start position:0% +so from the Fred home alternative you + + + align:start position:0% +so from the Fred home alternative you +know we get a lot of information about + + align:start position:0% +know we get a lot of information about + + + align:start position:0% +know we get a lot of information about +when we can solve equations but it also + + align:start position:0% +when we can solve equations but it also + + + align:start position:0% +when we can solve equations but it also +tells us I mean from that ability to say + + align:start position:0% +tells us I mean from that ability to say + + + align:start position:0% +tells us I mean from that ability to say +when we can solve equations we can also + + align:start position:0% +when we can solve equations we can also + + + align:start position:0% +when we can solve equations we can also +um + + align:start position:0% +um + + + align:start position:0% +um +characterize the non-zero spectrum of a + + align:start position:0% +characterize the non-zero spectrum of a + + + align:start position:0% +characterize the non-zero spectrum of a +self-adjoined compact operator + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +so we need to prove that so remember all + + align:start position:0% +so we need to prove that so remember all + + + align:start position:0% +so we need to prove that so remember all +of this just followed from you know + + align:start position:0% +of this just followed from you know + + + align:start position:0% +of this just followed from you know +stuff we had proven and the main result + + align:start position:0% +stuff we had proven and the main result + + + align:start position:0% +stuff we had proven and the main result +the main conclusion of the theorem which + + align:start position:0% +the main conclusion of the theorem which + + + align:start position:0% +the main conclusion of the theorem which +is that the range of a minus Lambda is + + align:start position:0% +is that the range of a minus Lambda is + + + align:start position:0% +is that the range of a minus Lambda is +closed so we need to prove that the + + align:start position:0% +closed so we need to prove that the + + + align:start position:0% +closed so we need to prove that the +range of a minus Lambda is closed when + + align:start position:0% +range of a minus Lambda is closed when + + + align:start position:0% +range of a minus Lambda is closed when +Lambda is a non-zero real number so um + + align:start position:0% +Lambda is a non-zero real number so um + + + align:start position:0% +Lambda is a non-zero real number so um +suppose that + + align:start position:0% +suppose that + + + align:start position:0% +suppose that +you have a sequence in the range which + + align:start position:0% +you have a sequence in the range which + + + align:start position:0% +you have a sequence in the range which +I'll write as a minus Lambda times u n + + align:start position:0% +I'll write as a minus Lambda times u n + + + align:start position:0% +I'll write as a minus Lambda times u n +converging to some element f + + align:start position:0% +converging to some element f + + + align:start position:0% +converging to some element f +in H + + align:start position:0% +in H + + + align:start position:0% +in H +okay so what we'd like to be able to + + align:start position:0% +okay so what we'd like to be able to + + + align:start position:0% +okay so what we'd like to be able to +show is that f is in the range + + align:start position:0% +show is that f is in the range + + + align:start position:0% +show is that f is in the range +so uh + + align:start position:0% + + + + align:start position:0% + +we want to show + + align:start position:0% + + + + align:start position:0% + +f is in the range of H + + align:start position:0% +f is in the range of H + + + align:start position:0% +f is in the range of H +or not range of H range of a + + align:start position:0% +or not range of H range of a + + + align:start position:0% +or not range of H range of a +uh minus Lambda sorry + + align:start position:0% +uh minus Lambda sorry + + + align:start position:0% +uh minus Lambda sorry +I hope I didn't make that mistake + + align:start position:0% +I hope I didn't make that mistake + + + align:start position:0% +I hope I didn't make that mistake +elsewhere no just + + align:start position:0% +elsewhere no just + + + align:start position:0% +elsewhere no just +okay + + align:start position:0% +okay + + + align:start position:0% +okay +now we're only assuming that a minus + + align:start position:0% +now we're only assuming that a minus + + + align:start position:0% +now we're only assuming that a minus +Lambda uh when it hits U sub n converges + + align:start position:0% +Lambda uh when it hits U sub n converges + + + align:start position:0% +Lambda uh when it hits U sub n converges +to F we're not a priori assuming the U + + align:start position:0% +to F we're not a priori assuming the U + + + align:start position:0% +to F we're not a priori assuming the U +sub n's converge okay in fact we can't + + align:start position:0% +sub n's converge okay in fact we can't + + + align:start position:0% +sub n's converge okay in fact we can't +um + + align:start position:0% +um + + + align:start position:0% +um +now but in the end we would like to come + + align:start position:0% +now but in the end we would like to come + + + align:start position:0% +now but in the end we would like to come +up with + + align:start position:0% +up with + + + align:start position:0% +up with +you know maybe a subsequence or or a + + align:start position:0% +you know maybe a subsequence or or a + + + align:start position:0% +you know maybe a subsequence or or a +part of the use of bins up to a + + align:start position:0% +part of the use of bins up to a + + + align:start position:0% +part of the use of bins up to a +subsequence which does converge and then + + align:start position:0% +subsequence which does converge and then + + + align:start position:0% +subsequence which does converge and then +we conclude that f is in the range all + + align:start position:0% +we conclude that f is in the range all + + + align:start position:0% +we conclude that f is in the range all +right so um + + align:start position:0% +right so um + + + align:start position:0% +right so um +first I want to get rid of kind of the + + align:start position:0% +first I want to get rid of kind of the + + + align:start position:0% +first I want to get rid of kind of the +useless part of the use of ends so uh + + align:start position:0% +useless part of the use of ends so uh + + + align:start position:0% +useless part of the use of ends so uh +let W be + + align:start position:0% + + + + align:start position:0% + +uh well I don't need to give it a name + + align:start position:0% +uh well I don't need to give it a name + + + align:start position:0% +uh well I don't need to give it a name +really + + align:start position:0% +really + + + align:start position:0% +really +it's my Eraser + + align:start position:0% + + + + align:start position:0% + +so let V in + + align:start position:0% +so let V in + + + align:start position:0% +so let V in +be the projection onto + + align:start position:0% + + + + align:start position:0% + +orthogonal complement of the null space + + align:start position:0% +orthogonal complement of the null space + + + align:start position:0% +orthogonal complement of the null space +of a minus Lambda of + + align:start position:0% +of a minus Lambda of + + + align:start position:0% +of a minus Lambda of +U sub n + + align:start position:0% +U sub n + + + align:start position:0% +U sub n +okay + + align:start position:0% +okay + + + align:start position:0% +okay +um + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% + + + + align:start position:0% + +now this is just part of so every use of + + align:start position:0% +now this is just part of so every use of + + + align:start position:0% +now this is just part of so every use of +n is written is you can write as + + align:start position:0% +n is written is you can write as + + + align:start position:0% +n is written is you can write as +something in the null space of a minus + + align:start position:0% +something in the null space of a minus + + + align:start position:0% +something in the null space of a minus +Lambda since uh + + align:start position:0% +Lambda since uh + + + align:start position:0% +Lambda since uh +so since null space of a minus Lambda is + + align:start position:0% +so since null space of a minus Lambda is + + + align:start position:0% +so since null space of a minus Lambda is +a closed Subspace of H + + align:start position:0% +a closed Subspace of H + + + align:start position:0% +a closed Subspace of H +it has an orthogonal complement so that + + align:start position:0% +it has an orthogonal complement so that + + + align:start position:0% +it has an orthogonal complement so that +it's it and its orthogonal complement + + align:start position:0% +it's it and its orthogonal complement + + + align:start position:0% +it's it and its orthogonal complement +gives a direct product uh + + align:start position:0% +gives a direct product uh + + + align:start position:0% +gives a direct product uh +or when you take their direct product + + align:start position:0% +or when you take their direct product + + + align:start position:0% +or when you take their direct product +gives you H right so + + align:start position:0% +gives you H right so + + + align:start position:0% +gives you H right so +um + + align:start position:0% + + + + align:start position:0% + +why am I saying that because then + + align:start position:0% +why am I saying that because then + + + align:start position:0% +why am I saying that because then +if I take a minus Lambda U sub n this is + + align:start position:0% +if I take a minus Lambda U sub n this is + + + align:start position:0% +if I take a minus Lambda U sub n this is +equal to + + align:start position:0% +equal to + + + align:start position:0% +equal to +a minus Lambda applied to + + align:start position:0% +a minus Lambda applied to + + + align:start position:0% +a minus Lambda applied to +Pi so the + + align:start position:0% +Pi so the + + + align:start position:0% +Pi so the +projection onto the null space of + + align:start position:0% +projection onto the null space of + + + align:start position:0% +projection onto the null space of +U sub n plus the projection onto the + + align:start position:0% +U sub n plus the projection onto the + + + align:start position:0% +U sub n plus the projection onto the +orthogonal complement of the null space + + align:start position:0% +orthogonal complement of the null space + + + align:start position:0% +orthogonal complement of the null space +which I defined as V sub n now this + + align:start position:0% +which I defined as V sub n now this + + + align:start position:0% +which I defined as V sub n now this +element here is in the null space of a + + align:start position:0% +element here is in the null space of a + + + align:start position:0% +element here is in the null space of a +minus Lambda so when a minus Lambda hits + + align:start position:0% +minus Lambda so when a minus Lambda hits + + + align:start position:0% +minus Lambda so when a minus Lambda hits +it I get zero so + + align:start position:0% +it I get zero so + + + align:start position:0% +it I get zero so +I get a minus Lambda applied to V sub n + + align:start position:0% +I get a minus Lambda applied to V sub n + + + align:start position:0% +I get a minus Lambda applied to V sub n +all right + + align:start position:0% + + + + align:start position:0% + +then a minus Lambda + + align:start position:0% +then a minus Lambda + + + align:start position:0% +then a minus Lambda +V sub n equals a minus Lambda U sub n + + align:start position:0% +V sub n equals a minus Lambda U sub n + + + align:start position:0% +V sub n equals a minus Lambda U sub n +which converges to F all right so + + align:start position:0% +which converges to F all right so + + + align:start position:0% +which converges to F all right so +basically I've taken away uh some noise + + align:start position:0% +basically I've taken away uh some noise + + + align:start position:0% +basically I've taken away uh some noise +all right all right uh the part that + + align:start position:0% +all right all right uh the part that + + + align:start position:0% +all right all right uh the part that +when it hits a minus Lambda I get zero + + align:start position:0% +when it hits a minus Lambda I get zero + + + align:start position:0% +when it hits a minus Lambda I get zero +so now I just have these Visa bins uh + + align:start position:0% +so now I just have these Visa bins uh + + + align:start position:0% +so now I just have these Visa bins uh +which lie in uh + + align:start position:0% +which lie in uh + + + align:start position:0% +which lie in uh +in the orthogonal complement + + align:start position:0% + + + + align:start position:0% + +of the null space of a minus Lambda + + align:start position:0% +of the null space of a minus Lambda + + + align:start position:0% +of the null space of a minus Lambda +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so + + align:start position:0% +so + + + align:start position:0% +so +my claim is + + align:start position:0% + + + + align:start position:0% + +first is that the sequence V sub n + + align:start position:0% + + + + align:start position:0% + +is bounded + + align:start position:0% +is bounded + + + align:start position:0% +is bounded +right basically once I can show this + + align:start position:0% +right basically once I can show this + + + align:start position:0% +right basically once I can show this +then I'm kind of done because if I can + + align:start position:0% +then I'm kind of done because if I can + + + align:start position:0% +then I'm kind of done because if I can +show V sub n is bounded then since a is + + align:start position:0% +show V sub n is bounded then since a is + + + align:start position:0% +show V sub n is bounded then since a is +a compact operator when a hits V sub n + + align:start position:0% +a compact operator when a hits V sub n + + + align:start position:0% +a compact operator when a hits V sub n +up to subsequence that converges okay + + align:start position:0% +up to subsequence that converges okay + + + align:start position:0% +up to subsequence that converges okay +now this whole expression converges and + + align:start position:0% +now this whole expression converges and + + + align:start position:0% +now this whole expression converges and +therefore Lambda times V sub n converges + + align:start position:0% +therefore Lambda times V sub n converges + + + align:start position:0% +therefore Lambda times V sub n converges +Lambda is non-zero so then V sub n + + align:start position:0% +Lambda is non-zero so then V sub n + + + align:start position:0% +Lambda is non-zero so then V sub n +converges up to a subsequence to + + align:start position:0% +converges up to a subsequence to + + + align:start position:0% +converges up to a subsequence to +something and therefore a minus Lambda V + + align:start position:0% +something and therefore a minus Lambda V + + + align:start position:0% +something and therefore a minus Lambda V +sub n converges to a minus Lambda of V + + align:start position:0% +sub n converges to a minus Lambda of V + + + align:start position:0% +sub n converges to a minus Lambda of V +for some V which shows that f is in the + + align:start position:0% +for some V which shows that f is in the + + + align:start position:0% +for some V which shows that f is in the +range of a minus Lambda so this is + + align:start position:0% +range of a minus Lambda so this is + + + align:start position:0% +range of a minus Lambda so this is +really the whole ball game + + align:start position:0% +really the whole ball game + + + align:start position:0% +really the whole ball game +um + + align:start position:0% +um + + + align:start position:0% +um +and we'll use here kind of crucially as + + align:start position:0% +and we'll use here kind of crucially as + + + align:start position:0% +and we'll use here kind of crucially as +well that we threw away useless parts of + + align:start position:0% +well that we threw away useless parts of + + + align:start position:0% +well that we threw away useless parts of +use of in useless at least to this + + align:start position:0% +use of in useless at least to this + + + align:start position:0% +use of in useless at least to this +argument + + align:start position:0% +argument + + + align:start position:0% +argument +um + + align:start position:0% +um + + + align:start position:0% +um +Okay so + + align:start position:0% +Okay so + + + align:start position:0% +Okay so +I claim uh this is bounded so suppose + + align:start position:0% +I claim uh this is bounded so suppose + + + align:start position:0% +I claim uh this is bounded so suppose +not + + align:start position:0% + + + + align:start position:0% + +then there exists + + align:start position:0% + + + + align:start position:0% + +subsequence call it V sub N Sub J + + align:start position:0% + + + + align:start position:0% + +such that uh + + align:start position:0% +such that uh + + + align:start position:0% +such that uh +um + + align:start position:0% +um + + + align:start position:0% +um +B sub N Sub J + + align:start position:0% +B sub N Sub J + + + align:start position:0% +B sub N Sub J +goes to Infinity + + align:start position:0% +goes to Infinity + + + align:start position:0% +goes to Infinity +okay as J goes to Infinity + + align:start position:0% + + + + align:start position:0% + +all right + + align:start position:0% +all right + + + align:start position:0% +all right +now if I look at a minus Lambda + + align:start position:0% +now if I look at a minus Lambda + + + align:start position:0% +now if I look at a minus Lambda +applied to V sub N Sub J + + align:start position:0% +applied to V sub N Sub J + + + align:start position:0% +applied to V sub N Sub J +over Norm of V sub N Sub J + + align:start position:0% +over Norm of V sub N Sub J + + + align:start position:0% +over Norm of V sub N Sub J +this converges so first off + + align:start position:0% +this converges so first off + + + align:start position:0% +this converges so first off +since a is a linear operator this is + + align:start position:0% +since a is a linear operator this is + + + align:start position:0% +since a is a linear operator this is +equal to 1 over Norm V and sub J times a + + align:start position:0% +equal to 1 over Norm V and sub J times a + + + align:start position:0% +equal to 1 over Norm V and sub J times a +minus Lambda applied to V sub N Sub J + + align:start position:0% +minus Lambda applied to V sub N Sub J + + + align:start position:0% +minus Lambda applied to V sub N Sub J +and so this scalar one over Norm v n sub + + align:start position:0% +and so this scalar one over Norm v n sub + + + align:start position:0% +and so this scalar one over Norm v n sub +J converges to zero this converges to f + + align:start position:0% +J converges to zero this converges to f + + + align:start position:0% +J converges to zero this converges to f +so I get the zero vector + + align:start position:0% +so I get the zero vector + + + align:start position:0% +so I get the zero vector +and H okay so + + align:start position:0% +and H okay so + + + align:start position:0% +and H okay so +um + + align:start position:0% +um + + + align:start position:0% +um +this thing converges to zero in the + + align:start position:0% +this thing converges to zero in the + + + align:start position:0% +this thing converges to zero in the +Hilbert space h + + align:start position:0% + + + + align:start position:0% + +now why is that bad because + + align:start position:0% +now why is that bad because + + + align:start position:0% +now why is that bad because +um + + align:start position:0% +um + + + align:start position:0% +um +essentially what this is going to say is + + align:start position:0% +essentially what this is going to say is + + + align:start position:0% +essentially what this is going to say is +that there exists some element + + align:start position:0% +that there exists some element + + + align:start position:0% +that there exists some element +or that this sequence converges at least + + align:start position:0% +or that this sequence converges at least + + + align:start position:0% +or that this sequence converges at least +up to a subsequence to an element V with + + align:start position:0% +up to a subsequence to an element V with + + + align:start position:0% +up to a subsequence to an element V with +Norm one because they all have Norm one + + align:start position:0% +Norm one because they all have Norm one + + + align:start position:0% +Norm one because they all have Norm one +so that a minus Lambda V equals zero but + + align:start position:0% +so that a minus Lambda V equals zero but + + + align:start position:0% +so that a minus Lambda V equals zero but +all of these are in the null space of a + + align:start position:0% +all of these are in the null space of a + + + align:start position:0% +all of these are in the null space of a +minus Lambda and we get a contradiction + + align:start position:0% +minus Lambda and we get a contradiction + + + align:start position:0% +minus Lambda and we get a contradiction +so + + align:start position:0% +so + + + align:start position:0% +so +um + + align:start position:0% + + + + align:start position:0% + +right so + + align:start position:0% +right so + + + align:start position:0% +right so +we have that + + align:start position:0% +we have that + + + align:start position:0% +we have that +a minus Lambda + + align:start position:0% +a minus Lambda + + + align:start position:0% +a minus Lambda +okay so we have that part + + align:start position:0% + + + + align:start position:0% + +since a is + + align:start position:0% + + + + align:start position:0% + +a compact operator + + align:start position:0% +a compact operator + + + align:start position:0% +a compact operator +uh + + align:start position:0% + + + + align:start position:0% + +exists the subsequence so a further + + align:start position:0% +exists the subsequence so a further + + + align:start position:0% +exists the subsequence so a further +subsequence I'm just going to call it N + + align:start position:0% +subsequence I'm just going to call it N + + + align:start position:0% +subsequence I'm just going to call it N +Sub K instead of N Sub J sub k + + align:start position:0% +Sub K instead of N Sub J sub k + + + align:start position:0% +Sub K instead of N Sub J sub k +uh + + align:start position:0% +uh + + + align:start position:0% +uh +B sub N Sub k + + align:start position:0% + + + + align:start position:0% + +of + + align:start position:0% +of + + + align:start position:0% +of +B sub N Sub J + + align:start position:0% + + + + align:start position:0% + +such that the sequence a sub V sub N Sub + + align:start position:0% +such that the sequence a sub V sub N Sub + + + align:start position:0% +such that the sequence a sub V sub N Sub +k + + align:start position:0% + + + + align:start position:0% + +converges + + align:start position:0% +converges + + + align:start position:0% +converges +okay + + align:start position:0% + + + + align:start position:0% + +but then I get that + + align:start position:0% +but then I get that + + + align:start position:0% +but then I get that +B sub N Sub K or I should say uh + + align:start position:0% + + + + align:start position:0% + +B sub N Sub K Over Norm or B sub N Sub k + + align:start position:0% +B sub N Sub K Over Norm or B sub N Sub k + + + align:start position:0% +B sub N Sub K Over Norm or B sub N Sub k +okay so these all have Norm one and a + + align:start position:0% +okay so these all have Norm one and a + + + align:start position:0% +okay so these all have Norm one and a +applied to something that has unit + + align:start position:0% +applied to something that has unit + + + align:start position:0% +applied to something that has unit +length uh + + align:start position:0% +length uh + + + align:start position:0% +length uh +or the image of by a of the closed unit + + align:start position:0% +or the image of by a of the closed unit + + + align:start position:0% +or the image of by a of the closed unit +ball is a pre-compact or the closure of + + align:start position:0% +ball is a pre-compact or the closure of + + + align:start position:0% +ball is a pre-compact or the closure of +it is Compact and therefore every + + align:start position:0% +it is Compact and therefore every + + + align:start position:0% +it is Compact and therefore every +sequence has a convergent subsequence + + align:start position:0% +sequence has a convergent subsequence + + + align:start position:0% +sequence has a convergent subsequence +um + + align:start position:0% +um + + + align:start position:0% +um +then B sub N Sub K Over Norm of V sub N + + align:start position:0% +then B sub N Sub K Over Norm of V sub N + + + align:start position:0% +then B sub N Sub K Over Norm of V sub N +Sub k + + align:start position:0% +Sub k + + + align:start position:0% +Sub k +this is equal to 1 over Lambda times + + align:start position:0% + + + + align:start position:0% + +a applied to V sub N Sub K over + + align:start position:0% +a applied to V sub N Sub K over + + + align:start position:0% +a applied to V sub N Sub K over +Norm of V sub N Sub K minus + + align:start position:0% +Norm of V sub N Sub K minus + + + align:start position:0% +Norm of V sub N Sub K minus +a minus Lambda Phi to V sub N Sub k + + align:start position:0% + + + + align:start position:0% + +now this + + align:start position:0% +now this + + + align:start position:0% +now this +sequence of elements converges to zero + + align:start position:0% +sequence of elements converges to zero + + + align:start position:0% +sequence of elements converges to zero +that's in fact what we just proved + + align:start position:0% +that's in fact what we just proved + + + align:start position:0% +that's in fact what we just proved +and this converges uh by how we've taken + + align:start position:0% +and this converges uh by how we've taken + + + align:start position:0% +and this converges uh by how we've taken +this subsequence because a is a compact + + align:start position:0% +this subsequence because a is a compact + + + align:start position:0% +this subsequence because a is a compact +operator so I have this sequence of + + align:start position:0% +operator so I have this sequence of + + + align:start position:0% +operator so I have this sequence of +vectors is equal to and here we can + + align:start position:0% +vectors is equal to and here we can + + + align:start position:0% +vectors is equal to and here we can +divide by Lambda because Lambda is + + align:start position:0% +divide by Lambda because Lambda is + + + align:start position:0% +divide by Lambda because Lambda is +non-zero + + align:start position:0% +non-zero + + + align:start position:0% +non-zero +it's equal to + + align:start position:0% +it's equal to + + + align:start position:0% +it's equal to +you know a linear combination of two + + align:start position:0% +you know a linear combination of two + + + align:start position:0% +you know a linear combination of two +sequences which converge + + align:start position:0% + + + + align:start position:0% + +and therefore we get that V sub N Sub k + + align:start position:0% +and therefore we get that V sub N Sub k + + + align:start position:0% +and therefore we get that V sub N Sub k +over Norm of + + align:start position:0% +over Norm of + + + align:start position:0% +over Norm of +P sub N Sub k k + + align:start position:0% + + + + align:start position:0% + +converges to + + align:start position:0% +converges to + + + align:start position:0% +converges to +uh + + align:start position:0% + + + + align:start position:0% + +an element B and + + align:start position:0% +an element B and + + + align:start position:0% +an element B and +now the null space or the orthogonal + + align:start position:0% +now the null space or the orthogonal + + + align:start position:0% +now the null space or the orthogonal +complement of the null space of a minus + + align:start position:0% +complement of the null space of a minus + + + align:start position:0% +complement of the null space of a minus +Lambda each of these is in + + align:start position:0% + + + + align:start position:0% + +remember the note the + + align:start position:0% +remember the note the + + + align:start position:0% +remember the note the +orthogonal complement of the null space + + align:start position:0% +orthogonal complement of the null space + + + align:start position:0% +orthogonal complement of the null space +and since it's converging to an element + + align:start position:0% +and since it's converging to an element + + + align:start position:0% +and since it's converging to an element +and this is closed + + align:start position:0% +and this is closed + + + align:start position:0% +and this is closed +this element has to be in the same + + align:start position:0% +this element has to be in the same + + + align:start position:0% +this element has to be in the same +set + + align:start position:0% +set + + + align:start position:0% +set +okay + + align:start position:0% + + + + align:start position:0% + +all right so again this follows from uh + + align:start position:0% +all right so again this follows from uh + + + align:start position:0% +all right so again this follows from uh +the fact that V is in here is because + + align:start position:0% +the fact that V is in here is because + + + align:start position:0% +the fact that V is in here is because +this set is closed all right the + + align:start position:0% +this set is closed all right the + + + align:start position:0% +this set is closed all right the +orthogonal complement of any subset of a + + align:start position:0% +orthogonal complement of any subset of a + + + align:start position:0% +orthogonal complement of any subset of a +Hilbert space is closed + + align:start position:0% + + + + align:start position:0% + +all right + + align:start position:0% + + + + align:start position:0% + +then + + align:start position:0% +then + + + align:start position:0% +then +by continuity of the norm basically the + + align:start position:0% +by continuity of the norm basically the + + + align:start position:0% +by continuity of the norm basically the +norm of V has to be equal to + + align:start position:0% +norm of V has to be equal to + + + align:start position:0% +norm of V has to be equal to +limit as K goes to Infinity of the norm + + align:start position:0% +limit as K goes to Infinity of the norm + + + align:start position:0% +limit as K goes to Infinity of the norm +of the elements + + align:start position:0% +of the elements + + + align:start position:0% +of the elements +converging to it + + align:start position:0% +converging to it + + + align:start position:0% +converging to it +which all equal one + + align:start position:0% +which all equal one + + + align:start position:0% +which all equal one +okay + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% + + + + align:start position:0% + +if I compute a minus Lambda applied to V + + align:start position:0% +if I compute a minus Lambda applied to V + + + align:start position:0% +if I compute a minus Lambda applied to V +this is equal to since the V sub N Sub K + + align:start position:0% +this is equal to since the V sub N Sub K + + + align:start position:0% +this is equal to since the V sub N Sub K +is over Norm V sub N Sub K's are + + align:start position:0% +is over Norm V sub N Sub K's are + + + align:start position:0% +is over Norm V sub N Sub K's are +converging to V + + align:start position:0% +converging to V + + + align:start position:0% +converging to V +a minus Lambda + + align:start position:0% +a minus Lambda + + + align:start position:0% +a minus Lambda +applied to V sub N Sub K Over Norm V sub + + align:start position:0% +applied to V sub N Sub K Over Norm V sub + + + align:start position:0% +applied to V sub N Sub K Over Norm V sub +N Sub K and remember this is a + + align:start position:0% +N Sub K and remember this is a + + + align:start position:0% +N Sub K and remember this is a +subsequence of V sub N Sub JS and when a + + align:start position:0% +subsequence of V sub N Sub JS and when a + + + align:start position:0% +subsequence of V sub N Sub JS and when a +minus Lambda hits that they're + + align:start position:0% +minus Lambda hits that they're + + + align:start position:0% +minus Lambda hits that they're +converging to zero so + + align:start position:0% + + + + align:start position:0% + +all right + + align:start position:0% +all right + + + align:start position:0% +all right +all of that predicated upon the + + align:start position:0% +all of that predicated upon the + + + align:start position:0% +all of that predicated upon the +assumption that the norm of V sub N Sub + + align:start position:0% +assumption that the norm of V sub N Sub + + + align:start position:0% +assumption that the norm of V sub N Sub +K's converges to uh infinity or that + + align:start position:0% +K's converges to uh infinity or that + + + align:start position:0% +K's converges to uh infinity or that +um right that the sequence is unbounded + + align:start position:0% +um right that the sequence is unbounded + + + align:start position:0% +um right that the sequence is unbounded +okay so we have this element uh in the + + align:start position:0% +okay so we have this element uh in the + + + align:start position:0% +okay so we have this element uh in the +null space + + align:start position:0% +null space + + + align:start position:0% +null space +that has uh or the orthogonal complement + + align:start position:0% +that has uh or the orthogonal complement + + + align:start position:0% +that has uh or the orthogonal complement +of the null space + + align:start position:0% +of the null space + + + align:start position:0% +of the null space +that has Norm one + + align:start position:0% +that has Norm one + + + align:start position:0% +that has Norm one +but also gives you zero + + align:start position:0% +but also gives you zero + + + align:start position:0% +but also gives you zero +and therefore + + align:start position:0% +and therefore + + + align:start position:0% +and therefore +we get that + + align:start position:0% +we get that + + + align:start position:0% +we get that +V is in + + align:start position:0% +V is in + + + align:start position:0% +V is in +the null space of a minus Lambda from + + align:start position:0% +the null space of a minus Lambda from + + + align:start position:0% +the null space of a minus Lambda from +this computation + + align:start position:0% +this computation + + + align:start position:0% +this computation +and uh + + align:start position:0% + + + + align:start position:0% + +it's orthogonal complement + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +but the only possible Vector that's in a + + align:start position:0% +but the only possible Vector that's in a + + + align:start position:0% +but the only possible Vector that's in a +space and its orthogonal complement is + + align:start position:0% +space and its orthogonal complement is + + + align:start position:0% +space and its orthogonal complement is +the zero vector or the + + align:start position:0% + + + + align:start position:0% + +only Vector in a Subspace and its + + align:start position:0% +only Vector in a Subspace and its + + + align:start position:0% +only Vector in a Subspace and its +orthogonal complement is the zero vector + + align:start position:0% +orthogonal complement is the zero vector + + + align:start position:0% +orthogonal complement is the zero vector +and therefore + + align:start position:0% + + + + align:start position:0% + +b equals zero which this is a + + align:start position:0% +b equals zero which this is a + + + align:start position:0% +b equals zero which this is a +contradiction to the fact that the norm + + align:start position:0% +contradiction to the fact that the norm + + + align:start position:0% +contradiction to the fact that the norm +of V equals one + + align:start position:0% +of V equals one + + + align:start position:0% +of V equals one +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so uh we started off with the sequence + + align:start position:0% +so uh we started off with the sequence + + + align:start position:0% +so uh we started off with the sequence +Visa bins assuming that they are + + align:start position:0% +Visa bins assuming that they are + + + align:start position:0% +Visa bins assuming that they are +unbounded V sub n over Norm V sub N is a + + align:start position:0% +unbounded V sub n over Norm V sub N is a + + + align:start position:0% +unbounded V sub n over Norm V sub N is a +sequence of + + align:start position:0% +sequence of + + + align:start position:0% +sequence of +essentially um so maybe you got lost in + + align:start position:0% +essentially um so maybe you got lost in + + + align:start position:0% +essentially um so maybe you got lost in +the subsequences but let's just assume + + align:start position:0% +the subsequences but let's just assume + + + align:start position:0% +the subsequences but let's just assume +I'm talking about the entire sequence + + align:start position:0% +I'm talking about the entire sequence + + + align:start position:0% +I'm talking about the entire sequence +then + + align:start position:0% +then + + + align:start position:0% +then +then V sub n over Norm V sub n uh when a + + align:start position:0% +then V sub n over Norm V sub n uh when a + + + align:start position:0% +then V sub n over Norm V sub n uh when a +minus Lambda hits it converges to zero + + align:start position:0% +minus Lambda hits it converges to zero + + + align:start position:0% +minus Lambda hits it converges to zero +since a is a compact operator we can + + align:start position:0% +since a is a compact operator we can + + + align:start position:0% +since a is a compact operator we can +choose a sub we can show essentially + + align:start position:0% +choose a sub we can show essentially + + + align:start position:0% +choose a sub we can show essentially +that a applied to V sub n over Norm V + + align:start position:0% +that a applied to V sub n over Norm V + + + align:start position:0% +that a applied to V sub n over Norm V +sub n because those things have unit + + align:start position:0% +sub n because those things have unit + + + align:start position:0% +sub n because those things have unit +length converges to something + + align:start position:0% +length converges to something + + + align:start position:0% +length converges to something +and since Lambda is non-zero we can then + + align:start position:0% +and since Lambda is non-zero we can then + + + align:start position:0% +and since Lambda is non-zero we can then +conclude that + + align:start position:0% +conclude that + + + align:start position:0% +conclude that +uh those vectors converge uh in fact to + + align:start position:0% +uh those vectors converge uh in fact to + + + align:start position:0% +uh those vectors converge uh in fact to +something not just their images by a or + + align:start position:0% +something not just their images by a or + + + align:start position:0% +something not just their images by a or +their images by a minus Lambda again + + align:start position:0% +their images by a minus Lambda again + + + align:start position:0% +their images by a minus Lambda again +because Lambda is non-zero all right and + + align:start position:0% +because Lambda is non-zero all right and + + + align:start position:0% +because Lambda is non-zero all right and +since they all have unit length + + align:start position:0% +since they all have unit length + + + align:start position:0% +since they all have unit length +their limit must have unit length + + align:start position:0% +their limit must have unit length + + + align:start position:0% +their limit must have unit length +and since when a minus Lambda hits these + + align:start position:0% +and since when a minus Lambda hits these + + + align:start position:0% +and since when a minus Lambda hits these +guys they go to zero + + align:start position:0% +guys they go to zero + + + align:start position:0% +guys they go to zero +the limit must also when a minus Lambda + + align:start position:0% +the limit must also when a minus Lambda + + + align:start position:0% +the limit must also when a minus Lambda +hit it equals zero and that gives us our + + align:start position:0% +hit it equals zero and that gives us our + + + align:start position:0% +hit it equals zero and that gives us our +contradiction because this limit V had + + align:start position:0% +contradiction because this limit V had + + + align:start position:0% +contradiction because this limit V had +to be in the null the orthogonal + + align:start position:0% +to be in the null the orthogonal + + + align:start position:0% +to be in the null the orthogonal +complement of the null space but then + + align:start position:0% +complement of the null space but then + + + align:start position:0% +complement of the null space but then +also in the null space and have unit + + align:start position:0% +also in the null space and have unit + + + align:start position:0% +also in the null space and have unit +length uh those three things can all + + align:start position:0% +length uh those three things can all + + + align:start position:0% +length uh those three things can all +happen at once + + align:start position:0% +happen at once + + + align:start position:0% +happen at once +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so uh + + align:start position:0% +so uh + + + align:start position:0% +so uh +thus + + align:start position:0% +thus + + + align:start position:0% +thus +this sequence V sub n + + align:start position:0% + + + + align:start position:0% + +is bounded okay so remember how was the + + align:start position:0% +is bounded okay so remember how was the + + + align:start position:0% +is bounded okay so remember how was the +V what were the Visa bins uh to start + + align:start position:0% +V what were the Visa bins uh to start + + + align:start position:0% +V what were the Visa bins uh to start +with they were so that a minus Lambda V + + align:start position:0% +with they were so that a minus Lambda V + + + align:start position:0% +with they were so that a minus Lambda V +sub n is converge to this element F and + + align:start position:0% +sub n is converge to this element F and + + + align:start position:0% +sub n is converge to this element F and +we wanted to show that f + + align:start position:0% +we wanted to show that f + + + align:start position:0% +we wanted to show that f +is in the range right so we + + align:start position:0% +is in the range right so we + + + align:start position:0% +is in the range right so we +coming back over here + + align:start position:0% +coming back over here + + + align:start position:0% +coming back over here +we had these Visa bins so that a minus + + align:start position:0% +we had these Visa bins so that a minus + + + align:start position:0% +we had these Visa bins so that a minus +Lambda V sub n converges to F and we + + align:start position:0% +Lambda V sub n converges to F and we + + + align:start position:0% +Lambda V sub n converges to F and we +want to show f is in the range to + + align:start position:0% +want to show f is in the range to + + + align:start position:0% +want to show f is in the range to +conclude that the range of a minus + + align:start position:0% +conclude that the range of a minus + + + align:start position:0% +conclude that the range of a minus +Lambda is closed + + align:start position:0% +Lambda is closed + + + align:start position:0% +Lambda is closed +but now that since it's bounded and + + align:start position:0% +but now that since it's bounded and + + + align:start position:0% +but now that since it's bounded and +we've kind of done this argument already + + align:start position:0% +we've kind of done this argument already + + + align:start position:0% +we've kind of done this argument already +this is essentially the whole ball game + + align:start position:0% + + + + align:start position:0% + +since the sequence V sub n is bounded + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% +and + + + align:start position:0% +and +a + + align:start position:0% +a + + + align:start position:0% +a +is a + + align:start position:0% +is a + + + align:start position:0% +is a +compact operator + + align:start position:0% +compact operator + + + align:start position:0% +compact operator +we conclude that + + align:start position:0% +we conclude that + + + align:start position:0% +we conclude that +um + + align:start position:0% +um + + + align:start position:0% +um +there exists a subsequence + + align:start position:0% + + + + align:start position:0% + +B sub N Sub J + + align:start position:0% +B sub N Sub J + + + align:start position:0% +B sub N Sub J +such that so this has nothing to do with + + align:start position:0% +such that so this has nothing to do with + + + align:start position:0% +such that so this has nothing to do with +the previous argument now but I just + + align:start position:0% +the previous argument now but I just + + + align:start position:0% +the previous argument now but I just +don't feel like using different letters + + align:start position:0% +don't feel like using different letters + + + align:start position:0% +don't feel like using different letters +such that a applied to V sub N Sub J + + align:start position:0% + + + + align:start position:0% + +converges + + align:start position:0% +converges + + + align:start position:0% +converges +so remember a is a compact operator + + align:start position:0% +so remember a is a compact operator + + + align:start position:0% +so remember a is a compact operator +which + + align:start position:0% +which + + + align:start position:0% +which +you know we stated in it in terms of the + + align:start position:0% +you know we stated in it in terms of the + + + align:start position:0% +you know we stated in it in terms of the +closure of the image of the closed unit + + align:start position:0% +closure of the image of the closed unit + + + align:start position:0% +closure of the image of the closed unit +ball being compact equivalently + + align:start position:0% +ball being compact equivalently + + + align:start position:0% +ball being compact equivalently +by scaling the unit ball + + align:start position:0% +by scaling the unit ball + + + align:start position:0% +by scaling the unit ball +it means that a takes any bounded + + align:start position:0% +it means that a takes any bounded + + + align:start position:0% +it means that a takes any bounded +sequence to + + align:start position:0% +sequence to + + + align:start position:0% +sequence to +a sequence that has a convergence + + align:start position:0% +a sequence that has a convergence + + + align:start position:0% +a sequence that has a convergence +subsequence okay + + align:start position:0% + + + + align:start position:0% + +so we showed V sub n is bounded and + + align:start position:0% +so we showed V sub n is bounded and + + + align:start position:0% +so we showed V sub n is bounded and +therefore since a is a compact operator + + align:start position:0% +therefore since a is a compact operator + + + align:start position:0% +therefore since a is a compact operator +we can find a subsequent so that when a + + align:start position:0% +we can find a subsequent so that when a + + + align:start position:0% +we can find a subsequent so that when a +hits it we have a convergent sequence + + align:start position:0% +hits it we have a convergent sequence + + + align:start position:0% +hits it we have a convergent sequence +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and by that same trick we used a minute + + align:start position:0% +and by that same trick we used a minute + + + align:start position:0% +and by that same trick we used a minute +ago we conclude that V sub N Sub J which + + align:start position:0% +ago we conclude that V sub N Sub J which + + + align:start position:0% +ago we conclude that V sub N Sub J which +is + + align:start position:0% +is + + + align:start position:0% +is +and we can do this because Lambda is + + align:start position:0% +and we can do this because Lambda is + + + align:start position:0% +and we can do this because Lambda is +non-zero we can divide by it + + align:start position:0% +non-zero we can divide by it + + + align:start position:0% +non-zero we can divide by it +um + + align:start position:0% +um + + + align:start position:0% +um +so a + + align:start position:0% +so a + + + align:start position:0% +so a +B sub N Sub J minus a minus Lambda V sub + + align:start position:0% +B sub N Sub J minus a minus Lambda V sub + + + align:start position:0% +B sub N Sub J minus a minus Lambda V sub +N Sub J now again this here is + + align:start position:0% +N Sub J now again this here is + + + align:start position:0% +N Sub J now again this here is +converging to something + + align:start position:0% +converging to something + + + align:start position:0% +converging to something +this here is converging to F right + + align:start position:0% +this here is converging to F right + + + align:start position:0% +this here is converging to F right +so this linear combination of convergent + + align:start position:0% +so this linear combination of convergent + + + align:start position:0% +so this linear combination of convergent +sequences is convergent + + align:start position:0% + + + + align:start position:0% + +converges + + align:start position:0% + + + + align:start position:0% + +to + + align:start position:0% +to + + + align:start position:0% +to +uh + + align:start position:0% + + + + align:start position:0% + +in element V + + align:start position:0% +in element V + + + align:start position:0% +in element V +and therefore I get that f + + align:start position:0% +and therefore I get that f + + + align:start position:0% +and therefore I get that f +which is + + align:start position:0% +which is + + + align:start position:0% +which is +the limit as n goes to Infinity of the V + + align:start position:0% +the limit as n goes to Infinity of the V + + + align:start position:0% +the limit as n goes to Infinity of the V +sub NS but + + align:start position:0% +sub NS but + + + align:start position:0% +sub NS but +convergence still holds if I look at a + + align:start position:0% +convergence still holds if I look at a + + + align:start position:0% +convergence still holds if I look at a +subsequence a minus Lambda + + align:start position:0% +subsequence a minus Lambda + + + align:start position:0% +subsequence a minus Lambda +V sub N Sub J equals and since a minus + + align:start position:0% +V sub N Sub J equals and since a minus + + + align:start position:0% +V sub N Sub J equals and since a minus +lamb so a is a bounded linear operator + + align:start position:0% +lamb so a is a bounded linear operator + + + align:start position:0% +lamb so a is a bounded linear operator +Lambda times the identity is a bounded + + align:start position:0% +Lambda times the identity is a bounded + + + align:start position:0% +Lambda times the identity is a bounded +linear operator this is equal to a minus + + align:start position:0% +linear operator this is equal to a minus + + + align:start position:0% +linear operator this is equal to a minus +Lambda + + align:start position:0% +Lambda + + + align:start position:0% +Lambda +V and therefore f is in the range + + align:start position:0% + + + + align:start position:0% + +of a minus Lambda + + align:start position:0% +of a minus Lambda + + + align:start position:0% +of a minus Lambda +Okay so + + align:start position:0% +Okay so + + + align:start position:0% +Okay so +uh Fred home alternative tells you that + + align:start position:0% +uh Fred home alternative tells you that + + + align:start position:0% +uh Fred home alternative tells you that +the range of a minus Lambda for a + + align:start position:0% +the range of a minus Lambda for a + + + align:start position:0% +the range of a minus Lambda for a +compact self-adjoined operator is closed + + align:start position:0% +compact self-adjoined operator is closed + + + align:start position:0% +compact self-adjoined operator is closed +um + + align:start position:0% + + + + align:start position:0% + +so you know where did we + + align:start position:0% +so you know where did we + + + align:start position:0% +so you know where did we +really use the fact that it was + + align:start position:0% +really use the fact that it was + + + align:start position:0% +really use the fact that it was +self-adjoint nowhere in this argument so + + align:start position:0% +self-adjoint nowhere in this argument so + + + align:start position:0% +self-adjoint nowhere in this argument so +this uh + + align:start position:0% +this uh + + + align:start position:0% +this uh +fact that the range of a minus Lambda is + + align:start position:0% +fact that the range of a minus Lambda is + + + align:start position:0% +fact that the range of a minus Lambda is +closed is still true if um you know a is + + align:start position:0% +closed is still true if um you know a is + + + align:start position:0% +closed is still true if um you know a is +just a compact operator and lambda's + + align:start position:0% +just a compact operator and lambda's + + + align:start position:0% +just a compact operator and lambda's +just some non-zero uh complex number + + align:start position:0% +just some non-zero uh complex number + + + align:start position:0% +just some non-zero uh complex number +um + + align:start position:0% +um + + + align:start position:0% +um +but where we use that itself a joint is + + align:start position:0% +but where we use that itself a joint is + + + align:start position:0% +but where we use that itself a joint is +kind of I guess in in the rest of the + + align:start position:0% +kind of I guess in in the rest of the + + + align:start position:0% +kind of I guess in in the rest of the +conclusion that the range of a minus + + align:start position:0% +conclusion that the range of a minus + + + align:start position:0% +conclusion that the range of a minus +Lambda is therefore equal to the null + + align:start position:0% +Lambda is therefore equal to the null + + + align:start position:0% +Lambda is therefore equal to the null +space of a minus Lambda and therefore + + align:start position:0% +space of a minus Lambda and therefore + + + align:start position:0% +space of a minus Lambda and therefore +either a minus Lambda is bijective or + + align:start position:0% +either a minus Lambda is bijective or + + + align:start position:0% +either a minus Lambda is bijective or +the null space of a minus Lambda is + + align:start position:0% +the null space of a minus Lambda is + + + align:start position:0% +the null space of a minus Lambda is +non-trivial and finite dimensional by + + align:start position:0% +non-trivial and finite dimensional by + + + align:start position:0% +non-trivial and finite dimensional by +what we did in the previous lecture + + align:start position:0% + + + + align:start position:0% + +foreign + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% + + + + align:start position:0% + +very + + align:start position:0% + + + + align:start position:0% + +powerful theorem + + align:start position:0% + + + + align:start position:0% + +and again what this says is that if I + + align:start position:0% +and again what this says is that if I + + + align:start position:0% +and again what this says is that if I +look at the non-zero spectrum of a + + align:start position:0% +look at the non-zero spectrum of a + + + align:start position:0% +look at the non-zero spectrum of a +compact self-adjoined operator then that + + align:start position:0% +compact self-adjoined operator then that + + + align:start position:0% +compact self-adjoined operator then that +consists entirely of eigenvalues of a + + align:start position:0% +consists entirely of eigenvalues of a + + + align:start position:0% +consists entirely of eigenvalues of a +right now earlier we proved that plus or + + align:start position:0% +right now earlier we proved that plus or + + + align:start position:0% +right now earlier we proved that plus or +minus the norm of a has to be in the + + align:start position:0% +minus the norm of a has to be in the + + + align:start position:0% +minus the norm of a has to be in the +Spectrum + + align:start position:0% +Spectrum + + + align:start position:0% +Spectrum +right of a self-adjoin operator + + align:start position:0% +right of a self-adjoin operator + + + align:start position:0% +right of a self-adjoin operator +and therefore what we can conclude is + + align:start position:0% +and therefore what we can conclude is + + + align:start position:0% +and therefore what we can conclude is +that if we have a non-trivial + + align:start position:0% +that if we have a non-trivial + + + align:start position:0% +that if we have a non-trivial +self-adjoint compact operator then it + + align:start position:0% +self-adjoint compact operator then it + + + align:start position:0% +self-adjoint compact operator then it +has a at least one eigenvalue + + align:start position:0% +has a at least one eigenvalue + + + align:start position:0% +has a at least one eigenvalue +and we can characterize that eigenvalue + + align:start position:0% +and we can characterize that eigenvalue + + + align:start position:0% +and we can characterize that eigenvalue +so this uh has a following theorem let + + align:start position:0% + + + + align:start position:0% + +a be a non-trivial uh + + align:start position:0% + + + + align:start position:0% + +compact self-adjoined operator a equals + + align:start position:0% +compact self-adjoined operator a equals + + + align:start position:0% +compact self-adjoined operator a equals +a star + + align:start position:0% + + + + align:start position:0% + +then + + align:start position:0% + + + + align:start position:0% + +as a + + align:start position:0% + + + + align:start position:0% + +non-trivial + + align:start position:0% + + + + align:start position:0% + +uh + + align:start position:0% + + + + align:start position:0% + +eigenvalue Lambda 1 + + align:start position:0% +eigenvalue Lambda 1 + + + align:start position:0% +eigenvalue Lambda 1 +and we can characterize Lambda one + + align:start position:0% +and we can characterize Lambda one + + + align:start position:0% +and we can characterize Lambda one +or at least the absolute value of Lambda + + align:start position:0% +or at least the absolute value of Lambda + + + align:start position:0% +or at least the absolute value of Lambda +1 as the supremum over + + align:start position:0% +1 as the supremum over + + + align:start position:0% +1 as the supremum over +Norm U equals one + + align:start position:0% +Norm U equals one + + + align:start position:0% +Norm U equals one +a u + + align:start position:0% +a u + + + align:start position:0% +a u +U + + align:start position:0% +U + + + align:start position:0% +U +okay + + align:start position:0% + + + + align:start position:0% + +uh + + align:start position:0% + + + + align:start position:0% + +equals and this supremum is actually + + align:start position:0% +equals and this supremum is actually + + + align:start position:0% +equals and this supremum is actually +achieved + + align:start position:0% + + + + align:start position:0% + +where U1 + + align:start position:0% + + + + align:start position:0% + +is a normalized eigenvector + + align:start position:0% +is a normalized eigenvector + + + align:start position:0% +is a normalized eigenvector +corresponding to Lambda 1. + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +all right so + + align:start position:0% +all right so + + + align:start position:0% +all right so +um + + align:start position:0% + + + + align:start position:0% + +why do we have or + + align:start position:0% +why do we have or + + + align:start position:0% +why do we have or +so I should say let me make sure I have + + align:start position:0% +so I should say let me make sure I have + + + align:start position:0% +so I should say let me make sure I have +everything here okay + + align:start position:0% +everything here okay + + + align:start position:0% +everything here okay +so why is this + + align:start position:0% + + + + align:start position:0% + +so first off we've shown that plus or + + align:start position:0% +so first off we've shown that plus or + + + align:start position:0% +so first off we've shown that plus or +minus + + align:start position:0% +minus + + + align:start position:0% +minus +the norm of a + + align:start position:0% +the norm of a + + + align:start position:0% +the norm of a +is in fact in + + align:start position:0% + + + + align:start position:0% + +the spectrum of a + + align:start position:0% +the spectrum of a + + + align:start position:0% +the spectrum of a +all right for any self-adjoint uh + + align:start position:0% +all right for any self-adjoint uh + + + align:start position:0% +all right for any self-adjoint uh +bounded linear operator not necessarily + + align:start position:0% +bounded linear operator not necessarily + + + align:start position:0% +bounded linear operator not necessarily +compact uh + + align:start position:0% + + + + align:start position:0% + +that plus or minus + + align:start position:0% +that plus or minus + + + align:start position:0% +that plus or minus +not necessarily both of them but plus or + + align:start position:0% +not necessarily both of them but plus or + + + align:start position:0% +not necessarily both of them but plus or +minus one of these + + align:start position:0% + + + + align:start position:0% + +at least one + + align:start position:0% +at least one + + + align:start position:0% +at least one +of plus or minus + + align:start position:0% +of plus or minus + + + align:start position:0% +of plus or minus +since a is self a joint meaning a star + + align:start position:0% +since a is self a joint meaning a star + + + align:start position:0% +since a is self a joint meaning a star +equals a + + align:start position:0% + + + + align:start position:0% + +uh + + align:start position:0% +uh + + + align:start position:0% +uh +then Lambda one + + align:start position:0% + + + + align:start position:0% + +then I'm going to say plus or minus + + align:start position:0% +then I'm going to say plus or minus + + + align:start position:0% +then I'm going to say plus or minus +meaning not both actually at least one + + align:start position:0% +meaning not both actually at least one + + + align:start position:0% +meaning not both actually at least one +of these uh + + align:start position:0% + + + + align:start position:0% + +is an eigenvalue of a + + align:start position:0% +is an eigenvalue of a + + + align:start position:0% +is an eigenvalue of a +by the Fret home alternative + + align:start position:0% + + + + align:start position:0% + +the Fred home alternative + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% + + + + align:start position:0% + +the fact that + + align:start position:0% + + + + align:start position:0% + +so Lambda 1 is going to be + + align:start position:0% +so Lambda 1 is going to be + + + align:start position:0% +so Lambda 1 is going to be +you know either + + align:start position:0% +you know either + + + align:start position:0% +you know either +plus Norm of a or minus Norm of a uh + + align:start position:0% +plus Norm of a or minus Norm of a uh + + + align:start position:0% +plus Norm of a or minus Norm of a uh +depending on whether which one is in the + + align:start position:0% +depending on whether which one is in the + + + align:start position:0% +depending on whether which one is in the +Spectrum let's say plus if it's in the + + align:start position:0% +Spectrum let's say plus if it's in the + + + align:start position:0% +Spectrum let's say plus if it's in the +Spectrum minus if plus is not and the + + align:start position:0% +Spectrum minus if plus is not and the + + + align:start position:0% +Spectrum minus if plus is not and the +fact that we can identify it as this + + align:start position:0% +fact that we can identify it as this + + + align:start position:0% +fact that we can identify it as this +quantity here is because + + align:start position:0% + + + + align:start position:0% + +we have that for self-adjoint operators + + align:start position:0% +we have that for self-adjoint operators + + + align:start position:0% +we have that for self-adjoint operators +Norm of a which is + + align:start position:0% +Norm of a which is + + + align:start position:0% +Norm of a which is +the absolute value of + + align:start position:0% +the absolute value of + + + align:start position:0% +the absolute value of +one of those plus or minuses that are in + + align:start position:0% +one of those plus or minuses that are in + + + align:start position:0% +one of those plus or minuses that are in +the spectrum is equal to so this is + + align:start position:0% +the spectrum is equal to so this is + + + align:start position:0% +the spectrum is equal to so this is +where + + align:start position:0% +where + + + align:start position:0% +where +so this is equal to + + align:start position:0% +so this is equal to + + + align:start position:0% +so this is equal to +um + + align:start position:0% + + + + align:start position:0% + +soup U equals one + + align:start position:0% +soup U equals one + + + align:start position:0% +soup U equals one +a u equals U + + align:start position:0% +a u equals U + + + align:start position:0% +a u equals U +okay + + align:start position:0% + + + + align:start position:0% + +all right + + align:start position:0% + + + + align:start position:0% + +so that's uh end of the proof + + align:start position:0% +so that's uh end of the proof + + + align:start position:0% +so that's uh end of the proof +and now what we're going to do is we are + + align:start position:0% +and now what we're going to do is we are + + + align:start position:0% +and now what we're going to do is we are +going to keep going all right + + align:start position:0% +going to keep going all right + + + align:start position:0% +going to keep going all right +um so the end result will be that + + align:start position:0% +um so the end result will be that + + + align:start position:0% +um so the end result will be that +we can + + align:start position:0% + + + + align:start position:0% + +determine all of the eigenvalues Via a + + align:start position:0% +determine all of the eigenvalues Via a + + + align:start position:0% +determine all of the eigenvalues Via a +certain maximum principle and build up a + + align:start position:0% +certain maximum principle and build up a + + + align:start position:0% +certain maximum principle and build up a +sequence of eigenvectors normalize + + align:start position:0% +sequence of eigenvectors normalize + + + align:start position:0% +sequence of eigenvectors normalize +eigenvectors which are pairwise + + align:start position:0% +eigenvectors which are pairwise + + + align:start position:0% +eigenvectors which are pairwise +orthogonal simply because they come from + + align:start position:0% +orthogonal simply because they come from + + + align:start position:0% +orthogonal simply because they come from +um + + align:start position:0% +um + + + align:start position:0% +um +how they're built up we'll see + + align:start position:0% + + + + align:start position:0% + +and what and then we'll show that + + align:start position:0% +and what and then we'll show that + + + align:start position:0% +and what and then we'll show that +essentially that set of eigenvectors + + align:start position:0% +essentially that set of eigenvectors + + + align:start position:0% +essentially that set of eigenvectors +that we get along with a set of or an + + align:start position:0% +that we get along with a set of or an + + + align:start position:0% +that we get along with a set of or an +orthonormal basis chosen for the null + + align:start position:0% +orthonormal basis chosen for the null + + + align:start position:0% +orthonormal basis chosen for the null +space of a uh form an orthonormal basis + + align:start position:0% +space of a uh form an orthonormal basis + + + align:start position:0% +space of a uh form an orthonormal basis +for a separable Hilbert space h + + align:start position:0% +for a separable Hilbert space h + + + align:start position:0% +for a separable Hilbert space h +okay so that's where we're going but we + + align:start position:0% +okay so that's where we're going but we + + + align:start position:0% +okay so that's where we're going but we +can basically + + align:start position:0% +can basically + + + align:start position:0% +can basically +take this theorem and keep applying it + + align:start position:0% +take this theorem and keep applying it + + + align:start position:0% +take this theorem and keep applying it +so we have the following maximum + + align:start position:0% +so we have the following maximum + + + align:start position:0% +so we have the following maximum +principle + + align:start position:0% + + + + align:start position:0% + +if you like this is the first step in a + + align:start position:0% +if you like this is the first step in a + + + align:start position:0% +if you like this is the first step in a +maximum principle this says if you want + + align:start position:0% +maximum principle this says if you want + + + align:start position:0% +maximum principle this says if you want +to find the largest eigenvalue Lambda 1. + + align:start position:0% + + + + align:start position:0% + +I should say I can even say largest + + align:start position:0% + + + + align:start position:0% + +eigenvalue + + align:start position:0% +eigenvalue + + + align:start position:0% +eigenvalue +largest in the sense of uh + + align:start position:0% +largest in the sense of uh + + + align:start position:0% +largest in the sense of uh +absolute value + + align:start position:0% +absolute value + + + align:start position:0% +absolute value +why because remember the spectrum is + + align:start position:0% +why because remember the spectrum is + + + align:start position:0% +why because remember the spectrum is +contained in the interval + + align:start position:0% +contained in the interval + + + align:start position:0% +contained in the interval +minus Norm a plus Norm of a okay so + + align:start position:0% +minus Norm a plus Norm of a okay so + + + align:start position:0% +minus Norm a plus Norm of a okay so +anything in the Spectrum has to have + + align:start position:0% +anything in the Spectrum has to have + + + align:start position:0% +anything in the Spectrum has to have +absolute value less than or equal to + + align:start position:0% +absolute value less than or equal to + + + align:start position:0% +absolute value less than or equal to +uh the norm of a + + align:start position:0% +uh the norm of a + + + align:start position:0% +uh the norm of a +and if it's a eigenvalue it's or if it's + + align:start position:0% +and if it's a eigenvalue it's or if it's + + + align:start position:0% +and if it's a eigenvalue it's or if it's +a + + align:start position:0% +a + + + align:start position:0% +a +right anything other than zero has to be + + align:start position:0% +right anything other than zero has to be + + + align:start position:0% +right anything other than zero has to be +an eigenvalue so we get uh get this + + align:start position:0% +an eigenvalue so we get uh get this + + + align:start position:0% +an eigenvalue so we get uh get this +okay so what's this maximum principle + + align:start position:0% +okay so what's this maximum principle + + + align:start position:0% +okay so what's this maximum principle +um and why was I saying all that oh so + + align:start position:0% +um and why was I saying all that oh so + + + align:start position:0% +um and why was I saying all that oh so +this gives you a way to to if you'd like + + align:start position:0% +this gives you a way to to if you'd like + + + align:start position:0% +this gives you a way to to if you'd like +try and find or at least approximate the + + align:start position:0% +try and find or at least approximate the + + + align:start position:0% +try and find or at least approximate the +first eigenvalue + + align:start position:0% +first eigenvalue + + + align:start position:0% +first eigenvalue +of a bounded linear operator right this + + align:start position:0% +of a bounded linear operator right this + + + align:start position:0% +of a bounded linear operator right this +is a maximization problem with a + + align:start position:0% +is a maximization problem with a + + + align:start position:0% +is a maximization problem with a +constraint yeah so you could use the + + align:start position:0% +constraint yeah so you could use the + + + align:start position:0% +constraint yeah so you could use the +method of LaGrange multipliers + + align:start position:0% +method of LaGrange multipliers + + + align:start position:0% +method of LaGrange multipliers +um you know + + align:start position:0% +um you know + + + align:start position:0% +um you know +that doesn't + + align:start position:0% +that doesn't + + + align:start position:0% +that doesn't +maybe make sense to you to be able to do + + align:start position:0% +maybe make sense to you to be able to do + + + align:start position:0% +maybe make sense to you to be able to do +on an infinite dimensional Hilbert space + + align:start position:0% +on an infinite dimensional Hilbert space + + + align:start position:0% +on an infinite dimensional Hilbert space +but let's say you choose a big basis uh + + align:start position:0% +but let's say you choose a big basis uh + + + align:start position:0% +but let's say you choose a big basis uh +of your Hilbert space and you just + + align:start position:0% +of your Hilbert space and you just + + + align:start position:0% +of your Hilbert space and you just +restrict to looking at that uh big but + + align:start position:0% +restrict to looking at that uh big but + + + align:start position:0% +restrict to looking at that uh big but +finite dimensional or finite basis uh + + align:start position:0% +finite dimensional or finite basis uh + + + align:start position:0% +finite dimensional or finite basis uh +or span of that finite basis and try to + + align:start position:0% +or span of that finite basis and try to + + + align:start position:0% +or span of that finite basis and try to +solve the approximate problem then you + + align:start position:0% +solve the approximate problem then you + + + align:start position:0% +solve the approximate problem then you +should get close to + + align:start position:0% +should get close to + + + align:start position:0% +should get close to +um + + align:start position:0% +um + + + align:start position:0% +um +the eigenvalue + + align:start position:0% +the eigenvalue + + + align:start position:0% +the eigenvalue +okay and get an approximate eigenvector + + align:start position:0% +okay and get an approximate eigenvector + + + align:start position:0% +okay and get an approximate eigenvector +because as I've said the eigenvector + + align:start position:0% +because as I've said the eigenvector + + + align:start position:0% +because as I've said the eigenvector +will be + + align:start position:0% +will be + + + align:start position:0% +will be +achieved + + align:start position:0% +achieved + + + align:start position:0% +achieved +or I should say the the eigenvector + + align:start position:0% +or I should say the the eigenvector + + + align:start position:0% +or I should say the the eigenvector +achieves this maximum here + + align:start position:0% +achieves this maximum here + + + align:start position:0% +achieves this maximum here +or the suprema okay so uh the maximum + + align:start position:0% +or the suprema okay so uh the maximum + + + align:start position:0% +or the suprema okay so uh the maximum +principle is the following so let a + + align:start position:0% + + + + align:start position:0% + +again we're only looking at compact + + align:start position:0% +again we're only looking at compact + + + align:start position:0% +again we're only looking at compact +self-adjoined operators + + align:start position:0% + + + + align:start position:0% + +compact + + align:start position:0% +compact + + + align:start position:0% +compact +operator + + align:start position:0% + + + + align:start position:0% + +then + + align:start position:0% + + + + align:start position:0% + +the non-zero eigenvalues + + align:start position:0% + + + + align:start position:0% + +of a + + align:start position:0% +of a + + + align:start position:0% +of a +can be ordered + + align:start position:0% +can be ordered + + + align:start position:0% +can be ordered +now this we kind of this part we already + + align:start position:0% +now this we kind of this part we already + + + align:start position:0% +now this we kind of this part we already +know they can be ordered + + align:start position:0% +know they can be ordered + + + align:start position:0% +know they can be ordered +Lambda 1 less than or equal to Lambda 2 + + align:start position:0% +Lambda 1 less than or equal to Lambda 2 + + + align:start position:0% +Lambda 1 less than or equal to Lambda 2 +less than or equal to Lambda 3. + + align:start position:0% +less than or equal to Lambda 3. + + + align:start position:0% +less than or equal to Lambda 3. +counted with multiplicity meaning + + align:start position:0% +counted with multiplicity meaning + + + align:start position:0% +counted with multiplicity meaning +uh if Lambda 1 has a two-dimensional + + align:start position:0% +uh if Lambda 1 has a two-dimensional + + + align:start position:0% +uh if Lambda 1 has a two-dimensional +eigenspace then Lambda 2 or the absolute + + align:start position:0% +eigenspace then Lambda 2 or the absolute + + + align:start position:0% +eigenspace then Lambda 2 or the absolute +value of or Lambda 2 will be Lambda 1 so + + align:start position:0% +value of or Lambda 2 will be Lambda 1 so + + + align:start position:0% +value of or Lambda 2 will be Lambda 1 so +we're we'll repeat it according to + + align:start position:0% +we're we'll repeat it according to + + + align:start position:0% +we're we'll repeat it according to +multiple Multiplicity + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% +um + + + align:start position:0% +um +so we know that there's finitely many + + align:start position:0% +so we know that there's finitely many + + + align:start position:0% +so we know that there's finitely many +distinct eigenvalues that was the part + + align:start position:0% +distinct eigenvalues that was the part + + + align:start position:0% +distinct eigenvalues that was the part +that I was saying we know we can order + + align:start position:0% +that I was saying we know we can order + + + align:start position:0% +that I was saying we know we can order +them but uh you know + + align:start position:0% +them but uh you know + + + align:start position:0% +them but uh you know +maybe it's it's uh not clear that you + + align:start position:0% +maybe it's it's uh not clear that you + + + align:start position:0% +maybe it's it's uh not clear that you +can order them with Multiplicity + + align:start position:0% +can order them with Multiplicity + + + align:start position:0% +can order them with Multiplicity +um + + align:start position:0% + + + + align:start position:0% + +with corresponding + + align:start position:0% + + + + align:start position:0% + +orthonormal + + align:start position:0% +orthonormal + + + align:start position:0% +orthonormal +eigenfunctions + + align:start position:0% + + + + align:start position:0% + +UK so U1 is a + + align:start position:0% +UK so U1 is a + + + align:start position:0% +UK so U1 is a +normalized eigenfunction for Lambda 1. + + align:start position:0% +normalized eigenfunction for Lambda 1. + + + align:start position:0% +normalized eigenfunction for Lambda 1. +U2 will be a normalized eigenfunction + + align:start position:0% +U2 will be a normalized eigenfunction + + + align:start position:0% +U2 will be a normalized eigenfunction +for Lambda 2 which is orthogonal to U1 + + align:start position:0% +for Lambda 2 which is orthogonal to U1 + + + align:start position:0% +for Lambda 2 which is orthogonal to U1 +so these are pairwise orthonormal + + align:start position:0% + + + + align:start position:0% + +and how do we obtain + + align:start position:0% +and how do we obtain + + + align:start position:0% +and how do we obtain +uh + + align:start position:0% +uh + + + align:start position:0% +uh +the eigenvalues in this order and these + + align:start position:0% +the eigenvalues in this order and these + + + align:start position:0% +the eigenvalues in this order and these +eigenfunctions via the following process + + align:start position:0% + + + + align:start position:0% + +so that Lambda + + align:start position:0% + + + + align:start position:0% + +J is equal to the supremum Over All + + align:start position:0% +J is equal to the supremum Over All + + + align:start position:0% +J is equal to the supremum Over All +uh + + align:start position:0% +uh + + + align:start position:0% +uh +unit vectors + + align:start position:0% +unit vectors + + + align:start position:0% +unit vectors +that or are orthogonal to the first + + align:start position:0% +that or are orthogonal to the first + + + align:start position:0% +that or are orthogonal to the first +J minus one + + align:start position:0% + + + + align:start position:0% + +and this is equal to this will be + + align:start position:0% +and this is equal to this will be + + + align:start position:0% +and this is equal to this will be +achieved on the U sub J + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so we have the first one if you like we + + align:start position:0% +so we have the first one if you like we + + + align:start position:0% +so we have the first one if you like we +built up Lambda one U1 and now what this + + align:start position:0% +built up Lambda one U1 and now what this + + + align:start position:0% +built up Lambda one U1 and now what this +maximum principle theorem is saying is + + align:start position:0% +maximum principle theorem is saying is + + + align:start position:0% +maximum principle theorem is saying is +that we can kind of repeat this okay is + + align:start position:0% +that we can kind of repeat this okay is + + + align:start position:0% +that we can kind of repeat this okay is +that if we now look at + + align:start position:0% +that if we now look at + + + align:start position:0% +that if we now look at +um this quantity here the supremum over + + align:start position:0% +um this quantity here the supremum over + + + align:start position:0% +um this quantity here the supremum over +all Norm one uh vectors that are + + align:start position:0% +all Norm one uh vectors that are + + + align:start position:0% +all Norm one uh vectors that are +orthogonal to U1 + + align:start position:0% +orthogonal to U1 + + + align:start position:0% +orthogonal to U1 +then we're going to pick up uh + + align:start position:0% +then we're going to pick up uh + + + align:start position:0% +then we're going to pick up uh +the next largest eigenvalue counted with + + align:start position:0% +the next largest eigenvalue counted with + + + align:start position:0% +the next largest eigenvalue counted with +multiplicity meaning uh it'll be the + + align:start position:0% +multiplicity meaning uh it'll be the + + + align:start position:0% +multiplicity meaning uh it'll be the +absolute value of Lambda 2 which will be + + align:start position:0% +absolute value of Lambda 2 which will be + + + align:start position:0% +absolute value of Lambda 2 which will be +less than Lambda 1 if you know Lambda 1 + + align:start position:0% +less than Lambda 1 if you know Lambda 1 + + + align:start position:0% +less than Lambda 1 if you know Lambda 1 +is uh only has a one-dimensional + + align:start position:0% +is uh only has a one-dimensional + + + align:start position:0% +is uh only has a one-dimensional +eigenspace + + align:start position:0% +eigenspace + + + align:start position:0% +eigenspace +um + + align:start position:0% +um + + + align:start position:0% +um +or it'll be Lambda or that absolute + + align:start position:0% +or it'll be Lambda or that absolute + + + align:start position:0% +or it'll be Lambda or that absolute +value of Lambda 2 will be Lambda + + align:start position:0% +value of Lambda 2 will be Lambda + + + align:start position:0% +value of Lambda 2 will be Lambda +absolute value of Lambda 1 again if + + align:start position:0% +absolute value of Lambda 1 again if + + + align:start position:0% +absolute value of Lambda 1 again if +Lambda 1 has a let's say two dimensional + + align:start position:0% +Lambda 1 has a let's say two dimensional + + + align:start position:0% +Lambda 1 has a let's say two dimensional +eigenspace okay + + align:start position:0% +eigenspace okay + + + align:start position:0% +eigenspace okay +and if it had a three-dimensional + + align:start position:0% +and if it had a three-dimensional + + + align:start position:0% +and if it had a three-dimensional +eigenspace we would get the absolute + + align:start position:0% +eigenspace we would get the absolute + + + align:start position:0% +eigenspace we would get the absolute +value of Lambda 1 for + + align:start position:0% +value of Lambda 1 for + + + align:start position:0% +value of Lambda 1 for +um it would equal this number and this + + align:start position:0% +um it would equal this number and this + + + align:start position:0% +um it would equal this number and this +number as well okay so again these these + + align:start position:0% +number as well okay so again these these + + + align:start position:0% +number as well okay so again these these +um + + align:start position:0% +um + + + align:start position:0% +um +non-zero eigenvalues are + + align:start position:0% + + + + align:start position:0% + +can be ordered in this way + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% +um + + + align:start position:0% +um +oh and I left off one + + align:start position:0% + + + + align:start position:0% + +and the Lambda J is going to zero okay + + align:start position:0% + + + + align:start position:0% + +Okay so + + align:start position:0% +Okay so + + + align:start position:0% +Okay so +we have the first one uh the absolute + + align:start position:0% +we have the first one uh the absolute + + + align:start position:0% +we have the first one uh the absolute +value of Lambda 1 and the first + + align:start position:0% +value of Lambda 1 and the first + + + align:start position:0% +value of Lambda 1 and the first +eigenvector U1 and now we're just gonna + + align:start position:0% +eigenvector U1 and now we're just gonna + + + align:start position:0% +eigenvector U1 and now we're just gonna +basically repeat + + align:start position:0% +basically repeat + + + align:start position:0% +basically repeat +or apply the previous theorem + + align:start position:0% + + + + align:start position:0% + +to a modification of a + + align:start position:0% + + + + align:start position:0% + +now + + align:start position:0% +now + + + align:start position:0% +now +um + + align:start position:0% +um + + + align:start position:0% +um +I should say + + align:start position:0% + + + + align:start position:0% + +this is not entirely true because there + + align:start position:0% +this is not entirely true because there + + + align:start position:0% +this is not entirely true because there +may only be finitely many + + align:start position:0% + + + + align:start position:0% + +so really this should be a remark + + align:start position:0% +so really this should be a remark + + + align:start position:0% +so really this should be a remark +if + + align:start position:0% + + + + align:start position:0% + +the decreasing sequence + + align:start position:0% + + + + align:start position:0% + +does not terminate + + align:start position:0% + + + + align:start position:0% + +then uh + + align:start position:0% +then uh + + + align:start position:0% +then uh +the absolute value of the Lambda JS goes + + align:start position:0% +the absolute value of the Lambda JS goes + + + align:start position:0% +the absolute value of the Lambda JS goes +to zero + + align:start position:0% +to zero + + + align:start position:0% +to zero +okay + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% + + + + align:start position:0% + +now + + align:start position:0% +now + + + align:start position:0% +now +Okay so + + align:start position:0% + + + + align:start position:0% + +what's what's kind of the new bit + + align:start position:0% +what's what's kind of the new bit + + + align:start position:0% +what's what's kind of the new bit +um + + align:start position:0% +um + + + align:start position:0% +um +of information here you know we do know + + align:start position:0% +of information here you know we do know + + + align:start position:0% +of information here you know we do know +that we can + + align:start position:0% +that we can + + + align:start position:0% +that we can +um + + align:start position:0% +um + + + align:start position:0% +um +you know for each + + align:start position:0% +you know for each + + + align:start position:0% +you know for each +let's say capital N the number of + + align:start position:0% +let's say capital N the number of + + + align:start position:0% +let's say capital N the number of +eigenvalues outside of uh or with + + align:start position:0% +eigenvalues outside of uh or with + + + align:start position:0% +eigenvalues outside of uh or with +absolute value bigger than 1 over n + + align:start position:0% +absolute value bigger than 1 over n + + + align:start position:0% +absolute value bigger than 1 over n +um has to be finite so you know + + align:start position:0% +um has to be finite so you know + + + align:start position:0% +um has to be finite so you know +the fact that we can order them is not + + align:start position:0% +the fact that we can order them is not + + + align:start position:0% +the fact that we can order them is not +really + + align:start position:0% +really + + + align:start position:0% +really +that much new information in the fact + + align:start position:0% +that much new information in the fact + + + align:start position:0% +that much new information in the fact +that they have to go to zero if this + + align:start position:0% +that they have to go to zero if this + + + align:start position:0% +that they have to go to zero if this +sequence is infinite that's also not new + + align:start position:0% +sequence is infinite that's also not new + + + align:start position:0% +sequence is infinite that's also not new +information I mean we did prove that uh + + align:start position:0% +information I mean we did prove that uh + + + align:start position:0% +information I mean we did prove that uh +in a previous lecture that if you have + + align:start position:0% +in a previous lecture that if you have + + + align:start position:0% +in a previous lecture that if you have +um + + align:start position:0% + + + + align:start position:0% + +so there we proved it for a sequence of + + align:start position:0% +so there we proved it for a sequence of + + + align:start position:0% +so there we proved it for a sequence of +distinct eigenvalues but because we now + + align:start position:0% +distinct eigenvalues but because we now + + + align:start position:0% +distinct eigenvalues but because we now +know that each of these has a finite + + align:start position:0% +know that each of these has a finite + + + align:start position:0% +know that each of these has a finite +dimensional uh eigenspace you know if + + align:start position:0% +dimensional uh eigenspace you know if + + + align:start position:0% +dimensional uh eigenspace you know if +you just look back at the same proof or + + align:start position:0% +you just look back at the same proof or + + + align:start position:0% +you just look back at the same proof or +that proof you can make a small + + align:start position:0% +that proof you can make a small + + + align:start position:0% +that proof you can make a small +adjustment to be able to say that if you + + align:start position:0% +adjustment to be able to say that if you + + + align:start position:0% +adjustment to be able to say that if you +count the eigenvalues with multiplicity + + align:start position:0% +count the eigenvalues with multiplicity + + + align:start position:0% +count the eigenvalues with multiplicity +then also the sequence has to go to zero + + align:start position:0% +then also the sequence has to go to zero + + + align:start position:0% +then also the sequence has to go to zero +okay not just necessarily the sequence + + align:start position:0% +okay not just necessarily the sequence + + + align:start position:0% +okay not just necessarily the sequence +consisting of the distinct eigenvalues + + align:start position:0% +consisting of the distinct eigenvalues + + + align:start position:0% +consisting of the distinct eigenvalues +okay so let me make that small + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% +um + + + align:start position:0% +um +remark + + align:start position:0% +remark + + + align:start position:0% +remark +what the new piece is is that we can + + align:start position:0% +what the new piece is is that we can + + + align:start position:0% +what the new piece is is that we can +compute the eigenvalues in this way and + + align:start position:0% +compute the eigenvalues in this way and + + + align:start position:0% +compute the eigenvalues in this way and +choose the eigenvectors in this way + + align:start position:0% +choose the eigenvectors in this way + + + align:start position:0% +choose the eigenvectors in this way +okay + + align:start position:0% +okay + + + align:start position:0% +okay +that's the new piece and that's kind of + + align:start position:0% +that's the new piece and that's kind of + + + align:start position:0% +that's the new piece and that's kind of +what + + align:start position:0% +what + + + align:start position:0% +what +in the end we'll we'll + + align:start position:0% +in the end we'll we'll + + + align:start position:0% +in the end we'll we'll +use to be able to show that H can be or + + align:start position:0% +use to be able to show that H can be or + + + align:start position:0% +use to be able to show that H can be or +that a can basically be diagonalized or + + align:start position:0% +that a can basically be diagonalized or + + + align:start position:0% +that a can basically be diagonalized or +that you can find an orthonormal basis + + align:start position:0% +that you can find an orthonormal basis + + + align:start position:0% +that you can find an orthonormal basis +of a Hilbert space separable Hilbert + + align:start position:0% +of a Hilbert space separable Hilbert + + + align:start position:0% +of a Hilbert space separable Hilbert +space consisting entirely of + + align:start position:0% +space consisting entirely of + + + align:start position:0% +space consisting entirely of +eigenvectors of a + + align:start position:0% +eigenvectors of a + + + align:start position:0% +eigenvectors of a +okay all right so + + align:start position:0% + + + + align:start position:0% + +the construction + + align:start position:0% + + + + align:start position:0% + +proceeds + + align:start position:0% +proceeds + + + align:start position:0% +proceeds +inductively so you know at one point I + + align:start position:0% +inductively so you know at one point I + + + align:start position:0% +inductively so you know at one point I +said you know if you can do it for one + + align:start position:0% +said you know if you can do it for one + + + align:start position:0% +said you know if you can do it for one +then you can do it for the next and then + + align:start position:0% +then you can do it for the next and then + + + align:start position:0% +then you can do it for the next and then +I won't be so formal every time I do a + + align:start position:0% +I won't be so formal every time I do a + + + align:start position:0% +I won't be so formal every time I do a +kind of an inductive uh construction and + + align:start position:0% +kind of an inductive uh construction and + + + align:start position:0% +kind of an inductive uh construction and +but in this case it pays to be careful + + align:start position:0% +but in this case it pays to be careful + + + align:start position:0% +but in this case it pays to be careful +so um + + align:start position:0% +so um + + + align:start position:0% +so um +you know we'll construct the + + align:start position:0% +you know we'll construct the + + + align:start position:0% +you know we'll construct the +sequence of uh Lambda J's in New in new + + align:start position:0% +sequence of uh Lambda J's in New in new + + + align:start position:0% +sequence of uh Lambda J's in New in new +case in this way all right + + align:start position:0% +case in this way all right + + + align:start position:0% +case in this way all right +um + + align:start position:0% +um + + + align:start position:0% +um +uh via an inductive argument Okay so + + align:start position:0% +uh via an inductive argument Okay so + + + align:start position:0% +uh via an inductive argument Okay so +uh + + align:start position:0% +uh + + + align:start position:0% +uh +coming up with k equals one that was the + + align:start position:0% +coming up with k equals one that was the + + + align:start position:0% +coming up with k equals one that was the +previous theorem right so + + align:start position:0% + + + + align:start position:0% + +previous or I should say uh + + align:start position:0% +previous or I should say uh + + + align:start position:0% +previous or I should say uh +J equals one that's the previous + + align:start position:0% +J equals one that's the previous + + + align:start position:0% +J equals one that's the previous +theorem right we defined we found the + + align:start position:0% +theorem right we defined we found the + + + align:start position:0% +theorem right we defined we found the +largest eigenvalue or the eigenvalue + + align:start position:0% +largest eigenvalue or the eigenvalue + + + align:start position:0% +largest eigenvalue or the eigenvalue +with the N eigenvalue with the largest + + align:start position:0% +with the N eigenvalue with the largest + + + align:start position:0% +with the N eigenvalue with the largest +absolute value + + align:start position:0% +absolute value + + + align:start position:0% +absolute value +via this theorem okay and then we + + align:start position:0% +via this theorem okay and then we + + + align:start position:0% +via this theorem okay and then we +obtained an eigenvector this way + + align:start position:0% +obtained an eigenvector this way + + + align:start position:0% +obtained an eigenvector this way +just basically as a consequence of the + + align:start position:0% +just basically as a consequence of the + + + align:start position:0% +just basically as a consequence of the +Fred home alternative and then that we + + align:start position:0% +Fred home alternative and then that we + + + align:start position:0% +Fred home alternative and then that we +know that plus or minus the norm of a + + align:start position:0% +know that plus or minus the norm of a + + + align:start position:0% +know that plus or minus the norm of a +has to be in the Spectrum Okay so + + align:start position:0% +has to be in the Spectrum Okay so + + + align:start position:0% +has to be in the Spectrum Okay so +the fact that we can find the first + + align:start position:0% +the fact that we can find the first + + + align:start position:0% +the fact that we can find the first +eigenvalued Lambda 1 that follows from + + align:start position:0% +eigenvalued Lambda 1 that follows from + + + align:start position:0% +eigenvalued Lambda 1 that follows from +the previous theorem so now we want to + + align:start position:0% +the previous theorem so now we want to + + + align:start position:0% +the previous theorem so now we want to +do the inductive step + + align:start position:0% + + + + align:start position:0% + +I.E we want to suppose + + align:start position:0% + + + + align:start position:0% + +we have + + align:start position:0% + + + + align:start position:0% + +found + + align:start position:0% +found + + + align:start position:0% +found +Lambda 1 up to Lambda + + align:start position:0% +Lambda 1 up to Lambda + + + align:start position:0% +Lambda 1 up to Lambda +say what did I use here + + align:start position:0% +say what did I use here + + + align:start position:0% +say what did I use here +Lambda n so J equals in + + align:start position:0% + + + + align:start position:0% + +along with + + align:start position:0% +along with + + + align:start position:0% +along with +uh + + align:start position:0% + + + + align:start position:0% + +what the normal + + align:start position:0% +what the normal + + + align:start position:0% +what the normal +eigen + + align:start position:0% +eigen + + + align:start position:0% +eigen +vectors + + align:start position:0% +vectors + + + align:start position:0% +vectors +U1 up to u n + + align:start position:0% + + + + align:start position:0% + +satisfying + + align:start position:0% +satisfying + + + align:start position:0% +satisfying +um this uh + + align:start position:0% +um this uh + + + align:start position:0% +um this uh +maximum principle Okay so + + align:start position:0% +maximum principle Okay so + + + align:start position:0% +maximum principle Okay so +for J up to from J starting from + + align:start position:0% +for J up to from J starting from + + + align:start position:0% +for J up to from J starting from +starting at one up to n we've + + align:start position:0% +starting at one up to n we've + + + align:start position:0% +starting at one up to n we've +constructed or found the Lambda 2 Lambda + + align:start position:0% +constructed or found the Lambda 2 Lambda + + + align:start position:0% +constructed or found the Lambda 2 Lambda +3 up to Lambda n and the U1 up to U in + + align:start position:0% +3 up to Lambda n and the U1 up to U in + + + align:start position:0% +3 up to Lambda n and the U1 up to U in +satisfying that maximum property + + align:start position:0% + + + + align:start position:0% + +all right so + + align:start position:0% +all right so + + + align:start position:0% +all right so +um + + align:start position:0% +um + + + align:start position:0% +um +then there's two cases + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +case one is + + align:start position:0% +case one is + + + align:start position:0% +case one is +the fact that a minus + + align:start position:0% + + + + align:start position:0% + +a is equal to the sum from k equals 1 to + + align:start position:0% +a is equal to the sum from k equals 1 to + + + align:start position:0% +a is equal to the sum from k equals 1 to +n + + align:start position:0% +n + + + align:start position:0% +n +of + + align:start position:0% +of + + + align:start position:0% +of +Lambda k u + + align:start position:0% +Lambda k u + + + align:start position:0% +Lambda k u +inner product UK UK + + align:start position:0% + + + + align:start position:0% + +and therefore + + align:start position:0% + + + + align:start position:0% + +what this shows is that + + align:start position:0% + + + + align:start position:0% + +we found all the + + align:start position:0% +we found all the + + + align:start position:0% +we found all the +eigenvalues + + align:start position:0% + + + + align:start position:0% + +and the process terminates + + align:start position:0% + + + + align:start position:0% + +okay so this is kind of the degenerate + + align:start position:0% +okay so this is kind of the degenerate + + + align:start position:0% +okay so this is kind of the degenerate +case that a is a finite rank operator + + align:start position:0% +case that a is a finite rank operator + + + align:start position:0% +case that a is a finite rank operator +okay so I could have started this whole + + align:start position:0% +okay so I could have started this whole + + + align:start position:0% +okay so I could have started this whole +theorem off with let's assume a is not a + + align:start position:0% +theorem off with let's assume a is not a + + + align:start position:0% +theorem off with let's assume a is not a +finite rank operator and therefore we + + align:start position:0% +finite rank operator and therefore we + + + align:start position:0% +finite rank operator and therefore we +wouldn't have to deal with this case but + + align:start position:0% +wouldn't have to deal with this case but + + + align:start position:0% +wouldn't have to deal with this case but +I just stated it for an arbitrary a so + + align:start position:0% +I just stated it for an arbitrary a so + + + align:start position:0% +I just stated it for an arbitrary a so +there is the possibility that that + + align:start position:0% +there is the possibility that that + + + align:start position:0% +there is the possibility that that +sequence stopped okay we found all of + + align:start position:0% +sequence stopped okay we found all of + + + align:start position:0% +sequence stopped okay we found all of +the eigenvalues + + align:start position:0% +the eigenvalues + + + align:start position:0% +the eigenvalues +with multiplicity in this in this + + align:start position:0% +with multiplicity in this in this + + + align:start position:0% +with multiplicity in this in this +process + + align:start position:0% +process + + + align:start position:0% +process +and then the theorem or construction is + + align:start position:0% +and then the theorem or construction is + + + align:start position:0% +and then the theorem or construction is +done in that case + + align:start position:0% +done in that case + + + align:start position:0% +done in that case +in the case two + + align:start position:0% +in the case two + + + align:start position:0% +in the case two +is that it is not a finite rank operator + + align:start position:0% +is that it is not a finite rank operator + + + align:start position:0% +is that it is not a finite rank operator +so it's not equal to k equals 1 to n + + align:start position:0% + + + + align:start position:0% + +okay now we have to show how can we find + + align:start position:0% +okay now we have to show how can we find + + + align:start position:0% +okay now we have to show how can we find +uh Lambda sub n plus one okay and the + + align:start position:0% +uh Lambda sub n plus one okay and the + + + align:start position:0% +uh Lambda sub n plus one okay and the +eigenvector U sub n plus one + + align:start position:0% + + + + align:start position:0% + +let a sub n + + align:start position:0% +let a sub n + + + align:start position:0% +let a sub n +B + + align:start position:0% +B + + + align:start position:0% +B +the operator A minus + + align:start position:0% +the operator A minus + + + align:start position:0% +the operator A minus +k equals 1 to n Lambda K inner product U + + align:start position:0% +k equals 1 to n Lambda K inner product U + + + align:start position:0% +k equals 1 to n Lambda K inner product U +so should say a + + align:start position:0% +so should say a + + + align:start position:0% +so should say a +U + + align:start position:0% + + + + align:start position:0% + +sub k + + align:start position:0% +sub k + + + align:start position:0% +sub k +all right + + align:start position:0% + + + + align:start position:0% + +now note since we are in case two this + + align:start position:0% +now note since we are in case two this + + + align:start position:0% +now note since we are in case two this +operator is non-zero okay so we're + + align:start position:0% +operator is non-zero okay so we're + + + align:start position:0% +operator is non-zero okay so we're +basically going to apply the previous + + align:start position:0% +basically going to apply the previous + + + align:start position:0% +basically going to apply the previous +theorem now to this operator okay but + + align:start position:0% +theorem now to this operator okay but + + + align:start position:0% +theorem now to this operator okay but +let me first make a few remarks + + align:start position:0% + + + + align:start position:0% + +then a is + + align:start position:0% +then a is + + + align:start position:0% +then a is +a sub N is a + + align:start position:0% + + + + align:start position:0% + +this is something you can check it's a + + align:start position:0% +this is something you can check it's a + + + align:start position:0% +this is something you can check it's a +self itself a joint + + align:start position:0% + + + + align:start position:0% + +compact operator + + align:start position:0% +compact operator + + + align:start position:0% +compact operator +so why is itself a joint basically + + align:start position:0% +so why is itself a joint basically + + + align:start position:0% +so why is itself a joint basically +because a is Alpha joint + + align:start position:0% +because a is Alpha joint + + + align:start position:0% +because a is Alpha joint +and these Lambda K's are real numbers + + align:start position:0% +and these Lambda K's are real numbers + + + align:start position:0% +and these Lambda K's are real numbers +okay + + align:start position:0% +okay + + + align:start position:0% +okay +all right because eigenvalues have to be + + align:start position:0% +all right because eigenvalues have to be + + + align:start position:0% +all right because eigenvalues have to be +real because a is self a joint + + align:start position:0% +real because a is self a joint + + + align:start position:0% +real because a is self a joint +um + + align:start position:0% +um + + + align:start position:0% +um +and these are orthonormal + + align:start position:0% +and these are orthonormal + + + align:start position:0% +and these are orthonormal +um so + + align:start position:0% +um so + + + align:start position:0% +um so +that is why they're self-adjoint why is + + align:start position:0% +that is why they're self-adjoint why is + + + align:start position:0% +that is why they're self-adjoint why is +it a compact operator well it's the sum + + align:start position:0% +it a compact operator well it's the sum + + + align:start position:0% +it a compact operator well it's the sum +of a compact operator a in a finite rank + + align:start position:0% +of a compact operator a in a finite rank + + + align:start position:0% +of a compact operator a in a finite rank +operator here so it's also a compact + + align:start position:0% +operator here so it's also a compact + + + align:start position:0% +operator here so it's also a compact +operator + + align:start position:0% +operator + + + align:start position:0% +operator +uh and it's a non-trivial one because + + align:start position:0% +uh and it's a non-trivial one because + + + align:start position:0% +uh and it's a non-trivial one because +it's not identically equal to zero + + align:start position:0% +it's not identically equal to zero + + + align:start position:0% +it's not identically equal to zero +so I shouldn't say not equal to zero but + + align:start position:0% +so I shouldn't say not equal to zero but + + + align:start position:0% +so I shouldn't say not equal to zero but +which is not identically the zero + + align:start position:0% +which is not identically the zero + + + align:start position:0% +which is not identically the zero +operator + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +all right so here's a couple of facts uh + + align:start position:0% +all right so here's a couple of facts uh + + + align:start position:0% +all right so here's a couple of facts uh +that if you + + align:start position:0% +that if you + + + align:start position:0% +that if you +is in the span of U1 up to you in + + align:start position:0% +is in the span of U1 up to you in + + + align:start position:0% +is in the span of U1 up to you in +then + + align:start position:0% +then + + + align:start position:0% +then +I get that a sub n + + align:start position:0% +I get that a sub n + + + align:start position:0% +I get that a sub n +applied to U is the zero vector + + align:start position:0% +applied to U is the zero vector + + + align:start position:0% +applied to U is the zero vector +okay why is that so it suffices to check + + align:start position:0% +okay why is that so it suffices to check + + + align:start position:0% +okay why is that so it suffices to check +that this gives me this formula gives me + + align:start position:0% +that this gives me this formula gives me + + + align:start position:0% +that this gives me this formula gives me +zero When U is one of the uks now if you + + align:start position:0% +zero When U is one of the uks now if you + + + align:start position:0% +zero When U is one of the uks now if you +as one of the uks then this will be + + align:start position:0% +as one of the uks then this will be + + + align:start position:0% +as one of the uks then this will be +um + + align:start position:0% +um + + + align:start position:0% +um +one only when or let's say it's one of + + align:start position:0% +one only when or let's say it's one of + + + align:start position:0% +one only when or let's say it's one of +the U JS I need a different letter so if + + align:start position:0% +the U JS I need a different letter so if + + + align:start position:0% +the U JS I need a different letter so if +you is one of these UJS + + align:start position:0% +you is one of these UJS + + + align:start position:0% +you is one of these UJS +then this will give me one only when J + + align:start position:0% +then this will give me one only when J + + + align:start position:0% +then this will give me one only when J +equals K and I pick up Lambda J times u + + align:start position:0% +equals K and I pick up Lambda J times u + + + align:start position:0% +equals K and I pick up Lambda J times u +j and then I have a hitting U sub J and + + align:start position:0% +j and then I have a hitting U sub J and + + + align:start position:0% +j and then I have a hitting U sub J and +that spits out Lambda J times U sub J + + align:start position:0% +that spits out Lambda J times U sub J + + + align:start position:0% +that spits out Lambda J times U sub J +because U sub J is an eigenvector of a + + align:start position:0% +because U sub J is an eigenvector of a + + + align:start position:0% +because U sub J is an eigenvector of a +so then I get the same thing here and + + align:start position:0% +so then I get the same thing here and + + + align:start position:0% +so then I get the same thing here and +there and subtracting them gives me zero + + align:start position:0% +there and subtracting them gives me zero + + + align:start position:0% +there and subtracting them gives me zero +um + + align:start position:0% + + + + align:start position:0% + +now if U is orthogonal to + + align:start position:0% +now if U is orthogonal to + + + align:start position:0% +now if U is orthogonal to +uh the span of the U1 up to u n then I + + align:start position:0% +uh the span of the U1 up to u n then I + + + align:start position:0% +uh the span of the U1 up to u n then I +get + + align:start position:0% +get + + + align:start position:0% +get +a in a view + + align:start position:0% +a in a view + + + align:start position:0% +a in a view +equals a u + + align:start position:0% +equals a u + + + align:start position:0% +equals a u +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so you just see this If U is orthogonal + + align:start position:0% +so you just see this If U is orthogonal + + + align:start position:0% +so you just see this If U is orthogonal +to these then this whole term is zero + + align:start position:0% +to these then this whole term is zero + + + align:start position:0% +to these then this whole term is zero +okay and I just pick up a n u equals a u + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% + + + + align:start position:0% + +for All U in H + + align:start position:0% +for All U in H + + + align:start position:0% +for All U in H +the + + align:start position:0% +the + + + align:start position:0% +the +the span of U1 up to u n + + align:start position:0% +the span of U1 up to u n + + + align:start position:0% +the span of U1 up to u n +if I compute + + align:start position:0% +if I compute + + + align:start position:0% +if I compute +a and u inner product + + align:start position:0% +a and u inner product + + + align:start position:0% +a and u inner product +V this is equal to U + + align:start position:0% +V this is equal to U + + + align:start position:0% +V this is equal to U +a and v since a n is Alpha joint and + + align:start position:0% +a and v since a n is Alpha joint and + + + align:start position:0% +a and v since a n is Alpha joint and +since V is in the span of the u1s up to + + align:start position:0% +since V is in the span of the u1s up to + + + align:start position:0% +since V is in the span of the u1s up to +U Ends by the first property that's + + align:start position:0% +U Ends by the first property that's + + + align:start position:0% +U Ends by the first property that's +going to be zero so this equals zero and + + align:start position:0% +going to be zero so this equals zero and + + + align:start position:0% +going to be zero so this equals zero and +therefore + + align:start position:0% + + + + align:start position:0% + +um what have I shown I've shown that a + + align:start position:0% +um what have I shown I've shown that a + + + align:start position:0% +um what have I shown I've shown that a +and u inner product V is zero no matter + + align:start position:0% +and u inner product V is zero no matter + + + align:start position:0% +and u inner product V is zero no matter +what uh U is an h and therefore that + + align:start position:0% +what uh U is an h and therefore that + + + align:start position:0% +what uh U is an h and therefore that +means that V has to be in the orthogonal + + align:start position:0% +means that V has to be in the orthogonal + + + align:start position:0% +means that V has to be in the orthogonal +complement of the range + + align:start position:0% + + + + align:start position:0% + +okay so I said that backwards so anyways + + align:start position:0% +okay so I said that backwards so anyways + + + align:start position:0% +okay so I said that backwards so anyways +um + + align:start position:0% +um + + + align:start position:0% +um +here U is fixed V is the thing that's + + align:start position:0% +here U is fixed V is the thing that's + + + align:start position:0% +here U is fixed V is the thing that's +changing so what does this say U is + + align:start position:0% +changing so what does this say U is + + + align:start position:0% +changing so what does this say U is +fixed a and u inner product V when V is + + align:start position:0% +fixed a and u inner product V when V is + + + align:start position:0% +fixed a and u inner product V when V is +in the span has to be zero this holds + + align:start position:0% +in the span has to be zero this holds + + + align:start position:0% +in the span has to be zero this holds +for all V in the span + + align:start position:0% +for all V in the span + + + align:start position:0% +for all V in the span +and therefore Anu has to be in the + + align:start position:0% +and therefore Anu has to be in the + + + align:start position:0% +and therefore Anu has to be in the +orthogonal complement of the span of + + align:start position:0% +orthogonal complement of the span of + + + align:start position:0% +orthogonal complement of the span of +these guys so this proves that the range + + align:start position:0% +these guys so this proves that the range + + + align:start position:0% +these guys so this proves that the range +of a n + + align:start position:0% +of a n + + + align:start position:0% +of a n +is a subset of + + align:start position:0% +is a subset of + + + align:start position:0% +is a subset of +the orthogonal complement + + align:start position:0% + + + + align:start position:0% + +of U1 up to u n + + align:start position:0% + + + + align:start position:0% + +and okay so from this previous property + + align:start position:0% +and okay so from this previous property + + + align:start position:0% +and okay so from this previous property +we get one last property + + align:start position:0% + + + + align:start position:0% + +that if + + align:start position:0% +that if + + + align:start position:0% +that if +a Anu + + align:start position:0% +a Anu + + + align:start position:0% +a Anu +equals Lambda U + + align:start position:0% +equals Lambda U + + + align:start position:0% +equals Lambda U +is non-zero meaning we have a non-zero + + align:start position:0% +is non-zero meaning we have a non-zero + + + align:start position:0% +is non-zero meaning we have a non-zero +eigenvalue of a sub n + + align:start position:0% +eigenvalue of a sub n + + + align:start position:0% +eigenvalue of a sub n +uh then + + align:start position:0% + + + + align:start position:0% + +that implies that U + + align:start position:0% + + + + align:start position:0% + +so U is equal to one over Lambda a sub n + + align:start position:0% +so U is equal to one over Lambda a sub n + + + align:start position:0% +so U is equal to one over Lambda a sub n +applied to U in other words U is equal + + align:start position:0% +applied to U in other words U is equal + + + align:start position:0% +applied to U in other words U is equal +to a sub n applied to U over Lambda so + + align:start position:0% +to a sub n applied to U over Lambda so + + + align:start position:0% +to a sub n applied to U over Lambda so +that implies U is in the range of a sub + + align:start position:0% +that implies U is in the range of a sub + + + align:start position:0% +that implies U is in the range of a sub +n + + align:start position:0% +n + + + align:start position:0% +n +um + + align:start position:0% +um + + + align:start position:0% +um +which again is + + align:start position:0% + + + + align:start position:0% + +contained in the orthogonal complement + + align:start position:0% +contained in the orthogonal complement + + + align:start position:0% +contained in the orthogonal complement +of U1 up to U sub n and since it's in + + align:start position:0% +of U1 up to U sub n and since it's in + + + align:start position:0% +of U1 up to U sub n and since it's in +the orthogonal complement that means a + + align:start position:0% +the orthogonal complement that means a + + + align:start position:0% +the orthogonal complement that means a +sub n u equals a u + + align:start position:0% + + + + align:start position:0% + +so any non-zero eigenvalue of a sub n + + align:start position:0% +so any non-zero eigenvalue of a sub n + + + align:start position:0% +so any non-zero eigenvalue of a sub n +has to be a non-zero eigenvalue of a + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +now we just apply the previous theorem + + align:start position:0% + + + + align:start position:0% + +to um + + align:start position:0% +to um + + + align:start position:0% +to um +to a sub n to get the next eigen or next + + align:start position:0% +to a sub n to get the next eigen or next + + + align:start position:0% +to a sub n to get the next eigen or next +uh eigenvalue a sub n Plus or Lambda sub + + align:start position:0% +uh eigenvalue a sub n Plus or Lambda sub + + + align:start position:0% +uh eigenvalue a sub n Plus or Lambda sub +n plus 1 and eigenvector U sub n plus + + align:start position:0% +n plus 1 and eigenvector U sub n plus + + + align:start position:0% +n plus 1 and eigenvector U sub n plus +one + + align:start position:0% + + + + align:start position:0% + +all right the previous theorem + + align:start position:0% + + + + align:start position:0% + +a sub n + + align:start position:0% +a sub n + + + align:start position:0% +a sub n +has a + + align:start position:0% + + + + align:start position:0% + +non-zero eigenvalue + + align:start position:0% +non-zero eigenvalue + + + align:start position:0% +non-zero eigenvalue +which I will call Lambda n plus one + + align:start position:0% + + + + align:start position:0% + +with + + align:start position:0% + + + + align:start position:0% + +unit + + align:start position:0% + + + + align:start position:0% + +eigenvector + + align:start position:0% +eigenvector + + + align:start position:0% +eigenvector +U sub n plus one + + align:start position:0% + + + + align:start position:0% + +so that Lambda n plus one + + align:start position:0% +so that Lambda n plus one + + + align:start position:0% +so that Lambda n plus one +is equal to + + align:start position:0% +is equal to + + + align:start position:0% +is equal to +the soup over + + align:start position:0% +the soup over + + + align:start position:0% +the soup over +all uh + + align:start position:0% +all uh + + + align:start position:0% +all uh +Norm + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% + + + + align:start position:0% + +ah okay soup overall Norm uh or unit + + align:start position:0% +ah okay soup overall Norm uh or unit + + + align:start position:0% +ah okay soup overall Norm uh or unit +length vectors of absolute value of a + + align:start position:0% +length vectors of absolute value of a + + + align:start position:0% +length vectors of absolute value of a +sub n applied to U in a product U now + + align:start position:0% +sub n applied to U in a product U now + + + align:start position:0% +sub n applied to U in a product U now +this soup is overalls is the same uh + + align:start position:0% +this soup is overalls is the same uh + + + align:start position:0% +this soup is overalls is the same uh +soup overall + + align:start position:0% + + + + align:start position:0% + +one so that a sub n u is non-zero so + + align:start position:0% +one so that a sub n u is non-zero so + + + align:start position:0% +one so that a sub n u is non-zero so +that in particular includes + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +right so if U is in the span of U1 up to + + align:start position:0% +right so if U is in the span of U1 up to + + + align:start position:0% +right so if U is in the span of U1 up to +U in then a and u equals zero so the + + align:start position:0% +U in then a and u equals zero so the + + + align:start position:0% +U in then a and u equals zero so the +supremum overall unit length is the same + + align:start position:0% +supremum overall unit length is the same + + + align:start position:0% +supremum overall unit length is the same +as uh the supremum over everything in + + align:start position:0% +as uh the supremum over everything in + + + align:start position:0% +as uh the supremum over everything in +the orthogonal complement of these guys + + align:start position:0% +the orthogonal complement of these guys + + + align:start position:0% +the orthogonal complement of these guys +because these guys when you stick them + + align:start position:0% +because these guys when you stick them + + + align:start position:0% +because these guys when you stick them +into a in gives me uh zero so that's the + + align:start position:0% +into a in gives me uh zero so that's the + + + align:start position:0% +into a in gives me uh zero so that's the +same supremum but now also + + align:start position:0% +same supremum but now also + + + align:start position:0% +same supremum but now also +when you is in the orthogonal complement + + align:start position:0% +when you is in the orthogonal complement + + + align:start position:0% +when you is in the orthogonal complement +of these u1s up to u n this is equal to + + align:start position:0% + + + + align:start position:0% + +uh + + align:start position:0% + + + + align:start position:0% + +soup of + + align:start position:0% + + + + align:start position:0% + +U + + align:start position:0% + + + + align:start position:0% + +on the orthogonal complement of the U1 + + align:start position:0% +on the orthogonal complement of the U1 + + + align:start position:0% +on the orthogonal complement of the U1 +up to you ends a and u remember equals + + align:start position:0% +up to you ends a and u remember equals + + + align:start position:0% +up to you ends a and u remember equals +a u + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so that uh + + align:start position:0% + + + + align:start position:0% + +gives us you know the fact that I can + + align:start position:0% +gives us you know the fact that I can + + + align:start position:0% +gives us you know the fact that I can +find this from this uh + + align:start position:0% +find this from this uh + + + align:start position:0% +find this from this uh +supremum + + align:start position:0% + + + + align:start position:0% + +and so why okay so why does + + align:start position:0% + + + + align:start position:0% + +this eigenvector have to be in the + + align:start position:0% +this eigenvector have to be in the + + + align:start position:0% +this eigenvector have to be in the +orthogonal complement of + + align:start position:0% + + + + align:start position:0% + +uh U1 up to u n it's because I can + + align:start position:0% +uh U1 up to u n it's because I can + + + align:start position:0% +uh U1 up to u n it's because I can +choose it that way because again when a + + align:start position:0% +choose it that way because again when a + + + align:start position:0% +choose it that way because again when a +sub n hits any of anything in here I get + + align:start position:0% +sub n hits any of anything in here I get + + + align:start position:0% +sub n hits any of anything in here I get +zero okay + + align:start position:0% + + + + align:start position:0% + +I should say this is also equal to + + align:start position:0% +I should say this is also equal to + + + align:start position:0% +I should say this is also equal to +a n applied to u n plus one but it's uh + + align:start position:0% +a n applied to u n plus one but it's uh + + + align:start position:0% +a n applied to u n plus one but it's uh +that's the same as a applied to u n plus + + align:start position:0% +that's the same as a applied to u n plus + + + align:start position:0% +that's the same as a applied to u n plus +one + + align:start position:0% +one + + + align:start position:0% +one +u n plus one + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% + + + + align:start position:0% + +right okay and this is less than or + + align:start position:0% +right okay and this is less than or + + + align:start position:0% +right okay and this is less than or +equal to the soup over Norm U equals one + + align:start position:0% +equal to the soup over Norm U equals one + + + align:start position:0% +equal to the soup over Norm U equals one +U and + + align:start position:0% +U and + + + align:start position:0% +U and +span U1 up to U + + align:start position:0% +span U1 up to U + + + align:start position:0% +span U1 up to U +n minus 1 orthogonal complement + + align:start position:0% +n minus 1 orthogonal complement + + + align:start position:0% +n minus 1 orthogonal complement +a u applied to U which equals uh + + align:start position:0% + + + + align:start position:0% + +the absolute value of the nth eigenvalue + + align:start position:0% +the absolute value of the nth eigenvalue + + + align:start position:0% +the absolute value of the nth eigenvalue +counted with multiple multiplicity okay + + align:start position:0% +counted with multiple multiplicity okay + + + align:start position:0% +counted with multiple multiplicity okay +so we found uh + + align:start position:0% +so we found uh + + + align:start position:0% +so we found uh +the next eigenvalue in the sequence + + align:start position:0% +the next eigenvalue in the sequence + + + align:start position:0% +the next eigenvalue in the sequence +again of eigenvalues counted with + + align:start position:0% +again of eigenvalues counted with + + + align:start position:0% +again of eigenvalues counted with +Multiplicity + + align:start position:0% + + + + align:start position:0% + +okay so now we have uh we can conclude + + align:start position:0% +okay so now we have uh we can conclude + + + align:start position:0% +okay so now we have uh we can conclude +the following spectral theorem + + align:start position:0% + + + + align:start position:0% + +for compact self-adjoined operators uh + + align:start position:0% + + + + align:start position:0% + +let + + align:start position:0% +let + + + align:start position:0% +let +a be a + + align:start position:0% +a be a + + + align:start position:0% +a be a +self-adjoint compact operator + + align:start position:0% + + + + align:start position:0% + +on a + + align:start position:0% + + + + align:start position:0% + +separable + + align:start position:0% + + + + align:start position:0% + +Hilbert space h + + align:start position:0% + + + + align:start position:0% + +let + + align:start position:0% +let + + + align:start position:0% +let +M to 1 bigger than or equal to Lambda 2. + + align:start position:0% + + + + align:start position:0% + +the + + align:start position:0% + + + + align:start position:0% + +corresponding eigenvalues + + align:start position:0% + + + + align:start position:0% + +be the + + align:start position:0% + + + + align:start position:0% + +eigenvalues or I should say non-zero + + align:start position:0% +eigenvalues or I should say non-zero + + + align:start position:0% +eigenvalues or I should say non-zero +eigenvalues + + align:start position:0% + + + + align:start position:0% + +a counted again with multiplicity so uh + + align:start position:0% + + + + align:start position:0% + +counted with multiplicity as we've + + align:start position:0% +counted with multiplicity as we've + + + align:start position:0% +counted with multiplicity as we've +constructed in this uh theorem of which + + align:start position:0% +constructed in this uh theorem of which + + + align:start position:0% +constructed in this uh theorem of which +I call the maximum principle + + align:start position:0% +I call the maximum principle + + + align:start position:0% +I call the maximum principle +uh + + align:start position:0% +uh + + + align:start position:0% +uh +with + + align:start position:0% + + + + align:start position:0% + +corresponding + + align:start position:0% +corresponding + + + align:start position:0% +corresponding +um + + align:start position:0% + + + + align:start position:0% + +orthonormal + + align:start position:0% +orthonormal + + + align:start position:0% +orthonormal +eigenvectors + + align:start position:0% + + + + align:start position:0% + +UK so we have these eigenvectors + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% + + + + align:start position:0% + +coming from this process + + align:start position:0% + + + + align:start position:0% + +and the conclusion is + + align:start position:0% + + + + align:start position:0% + +uh + + align:start position:0% + + + + align:start position:0% + +this uh + + align:start position:0% +this uh + + + align:start position:0% +this uh +subset of eigenvectors or orthonormal + + align:start position:0% +subset of eigenvectors or orthonormal + + + align:start position:0% +subset of eigenvectors or orthonormal +eigenvectors is + + align:start position:0% +eigenvectors is + + + align:start position:0% +eigenvectors is +and + + align:start position:0% + + + + align:start position:0% + +orthonormal basis + + align:start position:0% +orthonormal basis + + + align:start position:0% +orthonormal basis +for + + align:start position:0% + + + + align:start position:0% + +the closure or for the range of a + + align:start position:0% + + + + align:start position:0% + +in fact we can upgrade that + + align:start position:0% + + + + align:start position:0% + +UK is in fact + + align:start position:0% + + + + align:start position:0% + +not the normal basis for + + align:start position:0% +not the normal basis for + + + align:start position:0% +not the normal basis for +the range of a closure + + align:start position:0% +the range of a closure + + + align:start position:0% +the range of a closure +and + + align:start position:0% + + + + align:start position:0% + +there exists + + align:start position:0% + + + + align:start position:0% + +North the normal + + align:start position:0% +North the normal + + + align:start position:0% +North the normal +basis + + align:start position:0% +basis + + + align:start position:0% +basis +call it + + align:start position:0% +call it + + + align:start position:0% +call it +uh F sub J + + align:start position:0% +uh F sub J + + + align:start position:0% +uh F sub J +of the null space + + align:start position:0% +of the null space + + + align:start position:0% +of the null space +of a if it's non-zero + + align:start position:0% +of a if it's non-zero + + + align:start position:0% +of a if it's non-zero +such that + + align:start position:0% + + + + align:start position:0% + +you + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +FJ + + align:start position:0% +FJ + + + align:start position:0% +FJ +uh + + align:start position:0% +uh + + + align:start position:0% +uh +so first off + + align:start position:0% +so first off + + + align:start position:0% +so first off +the union of these two + + align:start position:0% +the union of these two + + + align:start position:0% +the union of these two +sets of orthonormal vectors is then + + align:start position:0% +sets of orthonormal vectors is then + + + align:start position:0% +sets of orthonormal vectors is then +going to be again a subset of + + align:start position:0% +going to be again a subset of + + + align:start position:0% +going to be again a subset of +orthonormal vectors because all the fjs + + align:start position:0% +orthonormal vectors because all the fjs + + + align:start position:0% +orthonormal vectors because all the fjs +would correspond to the eigenvalue 0 + + align:start position:0% +would correspond to the eigenvalue 0 + + + align:start position:0% +would correspond to the eigenvalue 0 +and these uks would correspond to + + align:start position:0% +and these uks would correspond to + + + align:start position:0% +and these uks would correspond to +eigenvalues that are non-zero + + align:start position:0% +eigenvalues that are non-zero + + + align:start position:0% +eigenvalues that are non-zero +and by what we proved last time uh any + + align:start position:0% +and by what we proved last time uh any + + + align:start position:0% +and by what we proved last time uh any +eigenvector for two distinct eigenvalues + + align:start position:0% +eigenvector for two distinct eigenvalues + + + align:start position:0% +eigenvector for two distinct eigenvalues +would have to be orthonormal so this + + align:start position:0% +would have to be orthonormal so this + + + align:start position:0% +would have to be orthonormal so this +subset is orthonormal from this subset + + align:start position:0% +subset is orthonormal from this subset + + + align:start position:0% +subset is orthonormal from this subset +but moreover + + align:start position:0% +but moreover + + + align:start position:0% +but moreover +is + + align:start position:0% +is + + + align:start position:0% +is +worth the normal like I said but also an + + align:start position:0% +worth the normal like I said but also an + + + align:start position:0% +worth the normal like I said but also an +orthonormal basis + + align:start position:0% +orthonormal basis + + + align:start position:0% +orthonormal basis +for H okay + + align:start position:0% + + + + align:start position:0% + +so in other words I can find + + align:start position:0% +so in other words I can find + + + align:start position:0% +so in other words I can find +an orthonormal basis 4-H consisting + + align:start position:0% +an orthonormal basis 4-H consisting + + + align:start position:0% +an orthonormal basis 4-H consisting +entirely of eigenvectors of this uh + + align:start position:0% +entirely of eigenvectors of this uh + + + align:start position:0% +entirely of eigenvectors of this uh +self-adjoint compact operator + + align:start position:0% +self-adjoint compact operator + + + align:start position:0% +self-adjoint compact operator +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so I will have one piece of this basis + + align:start position:0% +so I will have one piece of this basis + + + align:start position:0% +so I will have one piece of this basis +coming from the null space and the other + + align:start position:0% +coming from the null space and the other + + + align:start position:0% +coming from the null space and the other +piece uh corresponding to + + align:start position:0% +piece uh corresponding to + + + align:start position:0% +piece uh corresponding to +non-zero eigenvalues + + align:start position:0% + + + + align:start position:0% + +so really two follows from one + + align:start position:0% +so really two follows from one + + + align:start position:0% +so really two follows from one +um + + align:start position:0% + + + + align:start position:0% + +not sure why I decided to State them + + align:start position:0% +not sure why I decided to State them + + + align:start position:0% +not sure why I decided to State them +separately but here we are + + align:start position:0% + + + + align:start position:0% + +so proof of one will show that UK is an + + align:start position:0% +so proof of one will show that UK is an + + + align:start position:0% +so proof of one will show that UK is an +orthonormal basis for the range of a + + align:start position:0% +orthonormal basis for the range of a + + + align:start position:0% +orthonormal basis for the range of a +so first off Note as we did in the + + align:start position:0% +so first off Note as we did in the + + + align:start position:0% +so first off Note as we did in the +previous proof that the process + + align:start position:0% + + + + align:start position:0% + +of + + align:start position:0% + + + + align:start position:0% + +obtaining the + + align:start position:0% +obtaining the + + + align:start position:0% +obtaining the +Lambda 1 or the eigenvalues + + align:start position:0% + + + + align:start position:0% + +and eigenvectors + + align:start position:0% + + + + align:start position:0% + +or the normal eigenvectors + + align:start position:0% +or the normal eigenvectors + + + align:start position:0% +or the normal eigenvectors +uh + + align:start position:0% + + + + align:start position:0% + +terminates + + align:start position:0% +terminates + + + align:start position:0% +terminates +if and only if + + align:start position:0% +if and only if + + + align:start position:0% +if and only if +um + + align:start position:0% + + + + align:start position:0% + +a was finite rank in other words there + + align:start position:0% +a was finite rank in other words there + + + align:start position:0% +a was finite rank in other words there +exists an N so that + + align:start position:0% +exists an N so that + + + align:start position:0% +exists an N so that +Au is this finite rink + + align:start position:0% +Au is this finite rink + + + align:start position:0% +Au is this finite rink +operator + + align:start position:0% + + + + align:start position:0% + +you and a product + + align:start position:0% + + + + align:start position:0% + +UK UK + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +in this case if it's a finite rank + + align:start position:0% +in this case if it's a finite rank + + + align:start position:0% +in this case if it's a finite rank +operator then the range is contained in + + align:start position:0% +operator then the range is contained in + + + align:start position:0% +operator then the range is contained in +UK the + + align:start position:0% + + + + align:start position:0% + +is + + align:start position:0% + + + + align:start position:0% + +which is what we wanted to prove for + + align:start position:0% +which is what we wanted to prove for + + + align:start position:0% +which is what we wanted to prove for +this case that a is this finite rank + + align:start position:0% +this case that a is this finite rank + + + align:start position:0% +this case that a is this finite rank +operator + + align:start position:0% +operator + + + align:start position:0% +operator +so suppose otherwise + + align:start position:0% + + + + align:start position:0% + +in other words the process does not + + align:start position:0% +in other words the process does not + + + align:start position:0% +in other words the process does not +terminate + + align:start position:0% + + + + align:start position:0% + +so that we have countably infinite many + + align:start position:0% +so that we have countably infinite many + + + align:start position:0% +so that we have countably infinite many +uh + + align:start position:0% +uh + + + align:start position:0% +uh +non-zero eigenvalues counted with + + align:start position:0% +non-zero eigenvalues counted with + + + align:start position:0% +non-zero eigenvalues counted with +multiplicity and uh and corresponding + + align:start position:0% +multiplicity and uh and corresponding + + + align:start position:0% +multiplicity and uh and corresponding +orthonormal eigenvectors U sub K all + + align:start position:0% +orthonormal eigenvectors U sub K all + + + align:start position:0% +orthonormal eigenvectors U sub K all +right + + align:start position:0% +right + + + align:start position:0% +right +so this is a more interesting + + align:start position:0% + + + + align:start position:0% + +so the eigenvalues are countably + + align:start position:0% +so the eigenvalues are countably + + + align:start position:0% +so the eigenvalues are countably +intimate + + align:start position:0% + + + + align:start position:0% + +okay so now we want to show so as in the + + align:start position:0% +okay so now we want to show so as in the + + + align:start position:0% +okay so now we want to show so as in the +remark + + align:start position:0% + + + + align:start position:0% + +that I made afterwards + + align:start position:0% +that I made afterwards + + + align:start position:0% +that I made afterwards +you know that + + align:start position:0% +you know that + + + align:start position:0% +you know that +these Lambda Kays have to go to zero + + align:start position:0% +these Lambda Kays have to go to zero + + + align:start position:0% +these Lambda Kays have to go to zero +okay + + align:start position:0% +okay + + + align:start position:0% +okay +now + + align:start position:0% +now + + + align:start position:0% +now +we want to prove that the uks are an + + align:start position:0% +we want to prove that the uks are an + + + align:start position:0% +we want to prove that the uks are an +orthodontal basis for the range of a + + align:start position:0% +orthodontal basis for the range of a + + + align:start position:0% +orthodontal basis for the range of a +what does that mean by definition that + + align:start position:0% +what does that mean by definition that + + + align:start position:0% +what does that mean by definition that +means that they're in maximal + + align:start position:0% +means that they're in maximal + + + align:start position:0% +means that they're in maximal +orthonormal subset of the range of a so + + align:start position:0% +orthonormal subset of the range of a so + + + align:start position:0% +orthonormal subset of the range of a so +we have to show that if something's in + + align:start position:0% +we have to show that if something's in + + + align:start position:0% +we have to show that if something's in +the range and it's orthogonal to every + + align:start position:0% +the range and it's orthogonal to every + + + align:start position:0% +the range and it's orthogonal to every +uh one of these eigenvectors then that + + align:start position:0% +uh one of these eigenvectors then that + + + align:start position:0% +uh one of these eigenvectors then that +thing has to be zero okay + + align:start position:0% + + + + align:start position:0% + +so the claim + + align:start position:0% + + + + align:start position:0% + +if f is in the range of a + + align:start position:0% + + + + align:start position:0% + +and for all k + + align:start position:0% +and for all k + + + align:start position:0% +and for all k +uh + + align:start position:0% +uh + + + align:start position:0% +uh +F inner product u k equals zero + + align:start position:0% +F inner product u k equals zero + + + align:start position:0% +F inner product u k equals zero +then + + align:start position:0% +then + + + align:start position:0% +then +f is a zero vector + + align:start position:0% +f is a zero vector + + + align:start position:0% +f is a zero vector +okay + + align:start position:0% + + + + align:start position:0% + +Okay so + + align:start position:0% + + + + align:start position:0% + +so this is the claim we want to prove so + + align:start position:0% +so this is the claim we want to prove so + + + align:start position:0% +so this is the claim we want to prove so +suppose we have something in the range + + align:start position:0% +suppose we have something in the range + + + align:start position:0% +suppose we have something in the range +that means we can write it as a times U + + align:start position:0% +that means we can write it as a times U + + + align:start position:0% +that means we can write it as a times U +and uh + + align:start position:0% +and uh + + + align:start position:0% +and uh +F inner product UK equals zero + + align:start position:0% +F inner product UK equals zero + + + align:start position:0% +F inner product UK equals zero +for all k + + align:start position:0% + + + + align:start position:0% + +it's in for all K uh if I + + align:start position:0% +it's in for all K uh if I + + + align:start position:0% +it's in for all K uh if I +look at Lambda k u inner product UK this + + align:start position:0% +look at Lambda k u inner product UK this + + + align:start position:0% +look at Lambda k u inner product UK this +is equal to + + align:start position:0% +is equal to + + + align:start position:0% +is equal to +um + + align:start position:0% +um + + + align:start position:0% +um +Lambda K is a real number so I can bring + + align:start position:0% +Lambda K is a real number so I can bring + + + align:start position:0% +Lambda K is a real number so I can bring +it all the way in + + align:start position:0% +it all the way in + + + align:start position:0% +it all the way in +get Lambda k u k and this is equal to U + + align:start position:0% +get Lambda k u k and this is equal to U + + + align:start position:0% +get Lambda k u k and this is equal to U +a applied to UK now a itself a joint so + + align:start position:0% +a applied to UK now a itself a joint so + + + align:start position:0% +a applied to UK now a itself a joint so +I can move this a over here to U + + align:start position:0% + + + + align:start position:0% + +and this is equal to f + + align:start position:0% +and this is equal to f + + + align:start position:0% +and this is equal to f +in a product UK equals zero for all k + + align:start position:0% + + + + align:start position:0% + +right + + align:start position:0% + + + + align:start position:0% + +so by this uh + + align:start position:0% + + + + align:start position:0% + +maximum principle which we proved just a + + align:start position:0% +maximum principle which we proved just a + + + align:start position:0% +maximum principle which we proved just a +minute ago + + align:start position:0% +minute ago + + + align:start position:0% +minute ago +we conclude that the norm of f + + align:start position:0% +we conclude that the norm of f + + + align:start position:0% +we conclude that the norm of f +which is equal to the norm of + + align:start position:0% +which is equal to the norm of + + + align:start position:0% +which is equal to the norm of +a u which is equal to the norm of A + + align:start position:0% +a u which is equal to the norm of A + + + align:start position:0% +a u which is equal to the norm of A +minus + + align:start position:0% + + + + align:start position:0% + +sum from k equals 1 to n of Lambda k + + align:start position:0% +sum from k equals 1 to n of Lambda k + + + align:start position:0% +sum from k equals 1 to n of Lambda k +U + + align:start position:0% +U + + + align:start position:0% +U +k + + align:start position:0% +k + + + align:start position:0% +k +um + + align:start position:0% + + + + align:start position:0% + +UK applied to you + + align:start position:0% +UK applied to you + + + align:start position:0% +UK applied to you +right because every one of these numbers + + align:start position:0% +right because every one of these numbers + + + align:start position:0% +right because every one of these numbers +is zero so I haven't + + align:start position:0% +is zero so I haven't + + + align:start position:0% +is zero so I haven't +subtracted off anything + + align:start position:0% +subtracted off anything + + + align:start position:0% +subtracted off anything +right + + align:start position:0% +right + + + align:start position:0% +right +this is + + align:start position:0% +this is + + + align:start position:0% +this is +uh + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +I can write this in terms of + + align:start position:0% +I can write this in terms of + + + align:start position:0% +I can write this in terms of +this a sub n + + align:start position:0% +this a sub n + + + align:start position:0% +this a sub n +applied to U where a sub n was this + + align:start position:0% +applied to U where a sub n was this + + + align:start position:0% +applied to U where a sub n was this +thing that or a sub n is this thing + + align:start position:0% +thing that or a sub n is this thing + + + align:start position:0% +thing that or a sub n is this thing +which + + align:start position:0% +which + + + align:start position:0% +which +by the previous uh + + align:start position:0% +by the previous uh + + + align:start position:0% +by the previous uh +or the proof of the maximization or the + + align:start position:0% +or the proof of the maximization or the + + + align:start position:0% +or the proof of the maximization or the +maximum principle is less than or equal + + align:start position:0% +maximum principle is less than or equal + + + align:start position:0% +maximum principle is less than or equal +to + + align:start position:0% +to + + + align:start position:0% +to +Lambda plus one n plus one of + + align:start position:0% +Lambda plus one n plus one of + + + align:start position:0% +Lambda plus one n plus one of +U because again + + align:start position:0% +U because again + + + align:start position:0% +U because again +um + + align:start position:0% + + + + align:start position:0% + +remember this + + align:start position:0% +remember this + + + align:start position:0% +remember this +thing here is the supremum overall use + + align:start position:0% +thing here is the supremum overall use + + + align:start position:0% +thing here is the supremum overall use +of unit length of a sub n applied to U + + align:start position:0% +of unit length of a sub n applied to U + + + align:start position:0% +of unit length of a sub n applied to U +so uh Lambda n plus 1 is less than or or + + align:start position:0% +so uh Lambda n plus 1 is less than or or + + + align:start position:0% +so uh Lambda n plus 1 is less than or or +this quantity here divided by the norm + + align:start position:0% +this quantity here divided by the norm + + + align:start position:0% +this quantity here divided by the norm +of U so that U is a unit length is + + align:start position:0% +of U so that U is a unit length is + + + align:start position:0% +of U so that U is a unit length is +always less than or equal to this + + align:start position:0% +always less than or equal to this + + + align:start position:0% +always less than or equal to this +quantity here + + align:start position:0% +quantity here + + + align:start position:0% +quantity here +but now Lambda so this I had a fixed + + align:start position:0% +but now Lambda so this I had a fixed + + + align:start position:0% +but now Lambda so this I had a fixed +thing here Norm of F and I've shown it's + + align:start position:0% +thing here Norm of F and I've shown it's + + + align:start position:0% +thing here Norm of F and I've shown it's +less than or equal to Lambda n plus 1 + + align:start position:0% +less than or equal to Lambda n plus 1 + + + align:start position:0% +less than or equal to Lambda n plus 1 +times the norm of U this is a fixed + + align:start position:0% +times the norm of U this is a fixed + + + align:start position:0% +times the norm of U this is a fixed +thing and the Lambda ends are converging + + align:start position:0% +thing and the Lambda ends are converging + + + align:start position:0% +thing and the Lambda ends are converging +to zero + + align:start position:0% + + + + align:start position:0% + +okay and thus + + align:start position:0% +okay and thus + + + align:start position:0% +okay and thus +I started off with something + + align:start position:0% +I started off with something + + + align:start position:0% +I started off with something +non-negative less than or equal to + + align:start position:0% +non-negative less than or equal to + + + align:start position:0% +non-negative less than or equal to +something converging to zero and + + align:start position:0% +something converging to zero and + + + align:start position:0% +something converging to zero and +therefore that + + align:start position:0% +therefore that + + + align:start position:0% +therefore that +thing had to be zero + + align:start position:0% +thing had to be zero + + + align:start position:0% +thing had to be zero +therefore f is zero Okay so + + align:start position:0% +therefore f is zero Okay so + + + align:start position:0% +therefore f is zero Okay so +um this proves one that these + + align:start position:0% +um this proves one that these + + + align:start position:0% +um this proves one that these +eigenvectors are + + align:start position:0% + + + + align:start position:0% + +a maximal orthonormal + + align:start position:0% +a maximal orthonormal + + + align:start position:0% +a maximal orthonormal +um + + align:start position:0% +um + + + align:start position:0% +um +subset of the range of a + + align:start position:0% + + + + align:start position:0% + +and for two we simply note uh + + align:start position:0% +and for two we simply note uh + + + align:start position:0% +and for two we simply note uh +that + + align:start position:0% + + + + align:start position:0% + +by one we have that the range + + align:start position:0% + + + + align:start position:0% + +today closure this is since the + + align:start position:0% +today closure this is since the + + + align:start position:0% +today closure this is since the +um eigenvectors are an orthonormal basis + + align:start position:0% +um eigenvectors are an orthonormal basis + + + align:start position:0% +um eigenvectors are an orthonormal basis +for the range of a the closure is + + align:start position:0% + + + + align:start position:0% + +contained in + + align:start position:0% + + + + align:start position:0% + +closure of the spans of the uks here + + align:start position:0% +closure of the spans of the uks here + + + align:start position:0% +closure of the spans of the uks here +this is a finite span + + align:start position:0% +this is a finite span + + + align:start position:0% +this is a finite span +um + + align:start position:0% + + + + align:start position:0% + +which remember this is by uh an + + align:start position:0% +which remember this is by uh an + + + align:start position:0% +which remember this is by uh an +assignment exercise this is equal to k c + + align:start position:0% +assignment exercise this is equal to k c + + + align:start position:0% +assignment exercise this is equal to k c +k u k such that + + align:start position:0% + + + + align:start position:0% + +and therefore + + align:start position:0% +and therefore + + + align:start position:0% +and therefore +this implies that + + align:start position:0% + + + + align:start position:0% + +is an orthonormal basis + + align:start position:0% +is an orthonormal basis + + + align:start position:0% +is an orthonormal basis +for + + align:start position:0% +for + + + align:start position:0% +for +the range of a + + align:start position:0% +the range of a + + + align:start position:0% +the range of a +closure + + align:start position:0% +closure + + + align:start position:0% +closure +and this is equal to + + align:start position:0% + + + + align:start position:0% + +the + + align:start position:0% + + + + align:start position:0% + +range of a + + align:start position:0% +range of a + + + align:start position:0% +range of a +orthogonal complement orthogonal + + align:start position:0% +orthogonal complement orthogonal + + + align:start position:0% +orthogonal complement orthogonal +complement + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% +um + + + align:start position:0% +um +which is equal to the null space + + align:start position:0% +which is equal to the null space + + + align:start position:0% +which is equal to the null space +of + + align:start position:0% +of + + + align:start position:0% +of +the orthogonal complement of the null + + align:start position:0% +the orthogonal complement of the null + + + align:start position:0% +the orthogonal complement of the null +space of a star a star equals a so we + + align:start position:0% +space of a star a star equals a so we + + + align:start position:0% +space of a star a star equals a so we +get that so the UK's the eigenvectors + + align:start position:0% +get that so the UK's the eigenvectors + + + align:start position:0% +get that so the UK's the eigenvectors +form an orthogonal or an orthonormal + + align:start position:0% +form an orthogonal or an orthonormal + + + align:start position:0% +form an orthogonal or an orthonormal +basis for the orthogonal complement of + + align:start position:0% +basis for the orthogonal complement of + + + align:start position:0% +basis for the orthogonal complement of +the null space of a so once we've chosen + + align:start position:0% +the null space of a so once we've chosen + + + align:start position:0% +the null space of a so once we've chosen +an orthonormal basis for + + align:start position:0% +an orthonormal basis for + + + align:start position:0% +an orthonormal basis for +uh null space of a that's it + + align:start position:0% + + + + align:start position:0% + +H is + + align:start position:0% +H is + + + align:start position:0% +H is +separable and the null space of a is a + + align:start position:0% +separable and the null space of a is a + + + align:start position:0% +separable and the null space of a is a +closed Subspace of H + + align:start position:0% + + + + align:start position:0% + +on no space of a + + align:start position:0% +on no space of a + + + align:start position:0% +on no space of a +separable and we've proven that every + + align:start position:0% +separable and we've proven that every + + + align:start position:0% +separable and we've proven that every +separable Hilbert space or + + align:start position:0% +separable Hilbert space or + + + align:start position:0% +separable Hilbert space or +even just uh okay so this is a closed + + align:start position:0% +even just uh okay so this is a closed + + + align:start position:0% +even just uh okay so this is a closed +one so it's a Hilbert space anyways but + + align:start position:0% +one so it's a Hilbert space anyways but + + + align:start position:0% +one so it's a Hilbert space anyways but +every separable Hilbert space has an + + align:start position:0% +every separable Hilbert space has an + + + align:start position:0% +every separable Hilbert space has an +orthonormal basis + + align:start position:0% + + + + align:start position:0% + +of + + align:start position:0% + + + + align:start position:0% + +and therefore again so we + + align:start position:0% +and therefore again so we + + + align:start position:0% +and therefore again so we +uh since these two + + align:start position:0% +uh since these two + + + align:start position:0% +uh since these two +call this + + align:start position:0% +call this + + + align:start position:0% +call this +FJ + + align:start position:0% + + + + align:start position:0% + +this is an orthonormal basis + + align:start position:0% +this is an orthonormal basis + + + align:start position:0% +this is an orthonormal basis +for + + align:start position:0% + + + + align:start position:0% + +the null space of a direct products + + align:start position:0% +the null space of a direct products + + + align:start position:0% +the null space of a direct products +null space of a + + align:start position:0% +null space of a + + + align:start position:0% +null space of a +orthogonal complement + + align:start position:0% +orthogonal complement + + + align:start position:0% +orthogonal complement +that equals h + + align:start position:0% +that equals h + + + align:start position:0% +that equals h +all right and just in the nick of time + + align:start position:0% +all right and just in the nick of time + + + align:start position:0% +all right and just in the nick of time +I'm finished + + align:start position:0% +I'm finished + + + align:start position:0% +I'm finished +so next time + + align:start position:0% +so next time + + + align:start position:0% +so next time +um + + align:start position:0% +um + + + align:start position:0% +um +where do we go from here we'll see some + + align:start position:0% +where do we go from here we'll see some + + + align:start position:0% +where do we go from here we'll see some +of this applied in a concrete setting of + + align:start position:0% +of this applied in a concrete setting of + + + align:start position:0% +of this applied in a concrete setting of +differential equations and also discuss + + align:start position:0% +differential equations and also discuss + + + align:start position:0% +differential equations and also discuss +the functional calculus \ No newline at end of file diff --git a/00PK6cUCbnU.txt b/00PK6cUCbnU.txt new file mode 100644 index 0000000000000000000000000000000000000000..5d101fa589637e5ffdbe24e9d3e1412c8c06bfe7 --- /dev/null +++ b/00PK6cUCbnU.txt @@ -0,0 +1,2998 @@ +The following +content is provided + +under a Creative +Commons license. + +Your support will help MIT +OpenCourseWare continue + +to offer high-quality +educational resources for free. + +To make a donation, or +view additional materials + +from hundreds of MIT courses, +visit MIT OpenCourseWare + +at ocw.mit.edu. + +PROFESSOR: OK. + +Let's start with our +standard starting + +point of the last few lectures. + +That is, we are +looking at some system. + +We tried to describe +it by some kind + +of a field, statistical +field after some averaging. + +That is, a function of position. + +And we are interested +in calculating something + +like a partition function +by integrating over + +all configurations of +the statistical field. + +And these configurations +have some kind of a weight. + +This weight we choose +to write as exponential + +of some kind of a-- something +like an effective Hamiltonian + +that depends on +the configuration + +that you're looking at. + +And of course, the main +thing faced with a problem + +that you haven't seen before is +to decide on what the field is + +that you are looking +at to average. + +And what kind of +symmetries and constraints + +you want to construct in +this form of the weight. + +In particular, we +are sort of focusing + +on this Landau-Ginzburg +model that + +describes phase transitions. + +And let's say in the +absence of magnetic field, + +we are interested in a system +that is rotationally symmetric. + +But the procedure is +reasonably standard. + +Maybe in some +cases you can solve + +a particular part of this. + +Let's call that part beta H0. + +In the context that +we are working with, + +it's the Gaussian part that +we have looked at before. + +So that's the +integral over space. + +We used this idea of locality. + +We had an expansion +in all things + +that are consistent with this. + +But for the purposes of +the exactly solvable part, + +we focus on the Gaussian. + +So there is a term that is +proportional to m squared, + +gradient of m squared +and higher-order terms. + +So clearly for the +time being, I'm + +ignoring the magnetic field. + +So let's say in this +formulation the problem that we + +are interested is how our +partition function depends + +on this coefficient, +which where it goes to 0, + +the Gaussian weight becomes +kind of unsustainable. + +Now, of course, we said that the +full problem has, in addition + +to this beta H0, a part that +involves the interaction. + +So what I have done is I +have written the weight + +as beta H0 and a part +that is an interaction. + +By interaction, I +really mean something + +that is not solvable within +the framework of Gaussian. + +In our case, what was +non-solvable is essentially + +anything-- and there +is infinity of terms-- + +that don't have +second-order powers of m. + +So we wrote terms like m to +the fourth, m to the sixth, + +and so forth. + +Now, the key to being +able to solve this problem + +was to make a transformation +to Fourier modes. + +So essentially, what +we did was to write + +our m of x as a sum +over Fourier modes. + +You could write it, let's +say, in the discrete form as e + +to the i q dot x. + +And whether I write e to +the i q dot x or minus i q + +dot x is not as +important as long as I'm + +consistent within +one session at least. + +And the normalization +that I used was 1 over V. + +And the reason I used +this normalization was + +that if I went to the +continuum, I could write it + +nicely as an integral +over q divided + +by the density of states. + +The V would disappear. + +e to the i q x m tilde of q. + +Now in particular if I +do that transformation, + +the Gaussian part simply +becomes 1 over V sum over q. + +Then the Fourier +transform of this kernel t + +plus k q squared and so forth +divided by 2 m of q discrete + +squared. + +Which if I go to the +continuum limit simply + +becomes an integral +over q t plus k q + +squared and so forth +over 2 m of q squared. + +Now, once I have the Gaussian +weight, from the Gaussian + +weight I can calculate +various averages. + +And the averages +are best described + +by noting that essentially +after this transformation + +I can also write my weight as a +product over the contributions + +of the different modes of +something that is of this form, + +e to the minus beta H0. + +Now written in terms +of these q modes, + +clearly it's a product of +independent contributions. + +And then of course, there will +be the u to be added later on. + +But when I have a product +of independent contributions + +for each q, I can immediately +see that if I look at, + +say, m evaluated for +some q, m evaluated + +for some different q +with the Gaussian weight. + +And when I calculate things +with the Gaussian weight, + +I put this index 0. + +So that's my 0 to order or +exactly solvable theory. + +And of course, we are +dealing here with a vector. + +So these things have +indices alpha and beta + +associated with them. + +And if I look at the +discrete version, + +I have a product over +Gaussians for each one of them. + +Clearly, I will +get 0 unless I am + +looking at the same components. + +And I'm looking at the same q. + +And in particular, +the constraint really + +is that q plus q prime +should add up to 0. + +And if those constraints +are satisfied, + +then I am looking at +the particular term + +in this Gaussian. + +And the expectation +value of m squared + +is simply the variance +that we can see + +is V divided by t plus k q +squared, q to the fourth, + +and so forth. + +And the thing is that most +of the time we will actually + +be looking at things directly +in the limit of the continuum + +where we replace sums q's +with integrals over q. + +And then we have to replace +this discrete delta function + +with a continuum delta function. + +And the procedure to +do that is that this + +becomes delta alpha beta. + +This combination +gets replaced by 2 pi + +to the d delta function +q plus q prime, + +where this is now a +direct delta function + +t plus k q squared plus l q +to the fourth and so forth. + +And the justification +for doing that is simply + +that the Kronecker +delta is defined such + +that if I sum over, let's +say, all q, the delta that + +is Kronecker, the +answer would be 0. + +Now, if I go to the +continuum limit, + +the sum over q I have to +replace with integral over q + +with a density of states, which +is V divided by 2 pi to the d. + +So if I want to replace +this with a continuum delta + +function of q, I have to get rid +of this 2 pi to the d over V. + +And that's what I have done. + +So basically, you +replace-- hopefully I + +didn't make a mistake. + +Yes. + +So the discrete delta I +replace with 1 over V. The V + +disappears and the 2 +pi to the d appears. + +OK? + +Now, the thing that +makes some difficulty + +is that whereas the rest of +these things that we have not + +included as part +of the Gaussian, + +because of the locality I +could write reasonably simply + +in the space x. + +When I go to the space q, +it becomes complicated. + +Because each m of x +here I have to replace + +with a sum or an integral. + +And I have four of those m's. + +So here, let's say for the +first term that involves u, + +I have in principle to go +over an integral associated + +with conversion of the first +m, conversion of the second m, + +third m. + +Each one of them will carry +a factor of 2 pi to the d. + +So there will be three of them. + +And the reason I didn't +write the fourth one + +is because after I do all +of that transformation, + +I will have an integral +over x of e to the i q1 + +dot x plus q2 dot x plus +q3 dot x plus q4 dot x. + +So I have an integral +of e to the i q + +dot x where q is the sum +of the four of them over x. + +And that gives me +a delta function + +that ensures the sum of +the four q's have to be 0. + +So basically, one of the +m's will carry now index q1. + +The other will carry index q2. + +The third will carry index q3. + +The fourth will carry index that +is minus q1 minus q2 minus q3. + +Yes? + +AUDIENCE: Does it matter +which indices for squaring it, + +or whatever? + +Sorry. + +Do you need a subscript +for alpha and beta? + +PROFESSOR: OK. + +That's what I was [INAUDIBLE]. + +So this m to the fourth is +really m squared m squared, + +where m squared is a +vector that is squared. + +So I have to put the indices-- +let's say alpha alpha-- + +that are summed +over all possibility + +to get the dot product here. + +And I have to put +the indices beta + +beta to have the +dot products here. + +OK? + +Now when I go to the +next term, clearly I + +will have a whole bunch more +integrals and things like that. + +So the e u terms do not +look as nice and clean. + +They were local in real space. + +But when I go to this Fourier +space, they become non-local. + +q's that are all +over this [INAUDIBLE] + +are going to be coupled to each +other through this expression. + +And that's also why it +is called interaction. + +Because in some sense, +previously each q was a mode + +by itself and these terms give +interactions between modes that + +have different q's. + +Yes? + +AUDIENCE: Is there +a way to understand + +that physically of why you +get coupling in Fourier space? + +[INAUDIBLE] higher +than [INAUDIBLE]. + +PROFESSOR: OK. + +So essentially, we +have a system that + +has translational symmetry. + +So when you have +translational symmetry, + +this Fourier vector q is +a good conserved quantity. + +It's like a momentum. + +So one thing that we have +is, in some sense, a particle + +or an excitation that +is going by itself + +with some particular momentum. + +But what these terms represent +is the possibility that you + +have, let's say, +two of these momenta + +coming and interacting +with each other + +and getting two +that are going out. + +Why is it [INAUDIBLE]? + +It's partly because +of the symmetries + +that we built into the problem. + +If I had written something +that was m cubed, + +I had the possibility +of 2 going to, 1 or 1 + +going to 2, et cetera. + +All right. + +I forgot to say one +more thing, which + +is that for the Gaussian theory, +I can calculate essentially + +all expectation values +most [INAUDIBLE] + +in this context of the +Fourier representation. + +So this was an +example of something + +that had two factors of m. + +But very soon, we will see +that we would need terms + +that, let's say, involve +m factors of n that + +are multiplied each other. + +So I have m alpha i of +qi-- something like that. + +And again, 0 for the +Gaussian expectation value. + +And if I have written things +the way that I have-- that is, + +I have no magnetic field. + +So I have m2 minus +m symmetry, clearly + +the answer is going +to be 0 if l is odd. + +If l is even, we have this +nice property of Gaussians + +that we described +in 8.333, which + +is that this will be the sum +over all pairs of averages. + +So something like +m1, m2, m3, m4. + +You can have m1 m2 +multiplying by m3 m4 average. + +m1 m3 average multiply +m2 m4 average. + +m1 m4 average multiplied +by m2 m3 average. + +And this is what's called +a Wick's theorem, which + +is an important property of +the Gaussian that we will use. + +So we know how to calculate +averages of things of interest, + +which are essentially product +of these factors of m, + +in the Gaussian theory. + +Now let's calculate +these averages + +in perturbation theory. + +So quite generally, if I want to +calculate the average of some O + +in a theory that involves +averaging over some function + +l-- so this could be some +trace, some completely + +unspecified things-- of a +weight that is like, say, + +e to the minus beta H0. + +A part that I can +do and a part that I + +want to treat as a small +change to what I can do. + +The procedure of +calculating the average + +is to multiply the +probability by the quantity + +that I want to average. + +And of course, the whole thing +has to be properly normalized. + +And this is the normalization, +which is the partition function + +that we had previously. + +Now, the whole idea +of perturbation + +is to assume that this +quantity u is small. + +So we start to expand +e to the minus u. + +I can certainly do +that very easily, + +let's say, in the denominator. + +I have e to the minus +beta H0, and then I + +have 1 minus u plus u squared +over 2 minus u cubed over 6. + +Basically, the usual +expansion of the exponential. + +In the numerator, I +have the same thing, + +except that there is an +I that is multiplying + +this expansion for the +operator, or the object that I + +want to calculate the average. + +Now, the first term that I +have in the denominator here, + +1 multiplied by all integrals +of e to the minus H0 + +is clearly what I would +call the partition function, + +or the normalization +that I would + +have for the Gaussian weight. + +So that's the first term. + +If I factor that out, +then the next term + +is u integrated against +the Gaussian weight + +and then properly normalized. + +So the next term will be the +average of u with the Gaussian + +or whatever other +0 to order weight + +is that I can calculate things +and I have indicated that by 0. + +And then I would +have 1/2 average + +of u squared 0 and so forth. + +And the series in the numerator +once I factor out the Z0 + +is pretty much the same except +that every term will have an o. + +The Z 0's naturally +I can cancel out. + +So what I have is +from the numerator o + +minus ou plus 1/2 ou squared. + +What I will do with +the denominator + +is to bring it in the +numerator regarding + +all of these as +a small quantity. + +So if I were to essentially +write this expression raised + +to the minus 1 power, I +can make a series expansion + +of all of these terms. + +So the first thing, if I +just had one over 1 minus u + +in the denominator, +it would come + +from 1 plus u plus u squared +and u cubed, et cetera. + +But I've only kept thing +to order of u squared. + +So when I then +correct it because + +of this thing in +the denominator, + +the 1/2 becomes minus +1/2 u squared 0. + +And then, there will be +order of u cubed terms. + +So the answer is the +product of two brackets. + +And I can reorganize that +product, again, in powers of u. + +The lowest-order term +is the 0 to order, + +or unperturbed average. + +And the first correction +comes from ou average. + +And then I have the +average of u average of u. + +You can see that something +like a variance or connected + +correlation or cumulant +appears because I + +have to subtract +out the averages. + +And then the next order +term, what will I have? + +I will write it as 1/2. + +I start with ou squared 0. + +Then I can multiply +this with this, + +so I will get minus 2 o u0 u0. + +And then I can multiply +o0 with those two terms. + +So I will have minus o0 +u squared 0 plus 2 o0-- + +this is over here. + +u0 squared and +higher-order terms. + +So basically, we can see +that the coefficients, + +as I have written, are going to +be essentially the coefficients + +that I would have if I were +to expand the exponential. + +So things like minus 1 to +the n over n factorial. + +And the leading +term in all cases + +is o u raised to +the n-th power 0, + +out of which are +subtracted various things. + +And the effect of +those subtractions, + +let's say we define +a quantity which + +is likely cumulants that we were +using in 8.333, which describe + +the subtractions that you would +have to define such an average. + +So that's the general structure. + +What this really +means-- and I sometimes + +call it cumulant or connected-- +will become apparent + +very shortly. + +This is the general result. + +We have a particular +case above, which + +is this Landau-Ginzburg theory +perturbed around the Gaussian. + +So let's calculate the simplest +one of our averages, this m + +alpha of q m beta of q prime, +not at the Gaussian level, + +but as a perturbation. + +And actually, for +practical reasons, + +I will just calculate the +effect of the first term, which + +is u m to the fourth. + +So I will expand in powers of u. + +But once you see +that, you would know + +how to do it for m to the sixth +and all the higher powers. + +So according to +what we have here, + +the first term is +m alpha of q m beta + +of q prime evaluated +with the Gaussian theory. + +The next term, this one, +involves the average + +of this entity and the u. + +So our u I have +written up there. + +So I have minus +from the first term. + +The terms that are +proportional to u, + +I will group together +coming from here. + +u itself involved this +integration over q1 q2 q3. + +And u involves +this m i of q1 m i + +of q2 mj of q3 mj of minus +q1 minus q2 minus q3. + +And I have to multiply it. + +So this is u. + +I have to multiply it by o. + +So I have m alpha of +q m beta of q prime. + +So this is my o. + +This is my u. + +And I have to take the +average of this term. + +But really, the average +operates on the m's, + +so it will go over here. + +So that's the average of ou. + +I have to subtract from that +the average of o average of u. + +So let me, again, +write the next term. + +u will be the same +bunch of integrations. + +I have to do average of +o and then average of u. + +This completes my first +correction coming from u, + +and then there will be +corrections to first order + +coming from V. There will be +second-order corrections coming + +from u squared, +all kinds of things + +that will come into play. + +But the important thing, again, +to realize is the structure. + +u is this thing that +involves four factors of m. + +The averages are +over the m, so I + +can take them +within the integral. + +And so I have one case which +is an expectation value of six + +m's. + +Another case, a product of +two and a product of four. + +So that's why I +said I would need + +to know how to calculate +in the Gaussian theory + +product of various factors +of m because my interaction + +term involves various powers +of m that will be added + +to whatever expectation value +I'm calculating perturbation + +theory. + +So how do I calculate +an expectation + +that involves six factors-- +certainly, it's even-- of m? + +I have to group-- make +all possible pairings. + +So this, for example, +can be paired to this. + +This can be paired to this. + +This can be paired to this. + +That's a perfectly +well-defined average. + +But you can see +that if I do this, + +if I pair this one, +this one, this one, + +I will get something that will +cancel out against this one. + +So basically, you can +see that any way that I + +do averaging that involves only +things that are coming from o + +and separately the +things that come from u + +will cancel out with the +corresponding-- oops. + +With the corresponding +averages that I do over here. + +That c stands for connected. + +So the only things that survive +are pairings or contractions + +that pick something +that is from o + +and connect it to +something that is from u. + +And the purpose of all of +these other terms at all higher + +orders is precisely +to remove pieces + +where you don't have full +connections among all + +of the o's and the u's +that you are dealing with. + +So let's see what this is. + +So I will show you that using +connections that involve both o + +and u, I will have two types of +contractions joining o and u. + +The first type is +something like this. + +I will, again, draw all-- or +write down all of the fours. + +So I have m alpha of q m beta of +q prime m i of q1 m i of q2 mj + +of q3 mj of minus q1 +minus q2 minus q3. + +I have to take that average. + +And I do that the +average according + +to Wick's theorem as a +product of contractions. + +So let's pick this m alpha. + +It has to ultimately be +paired with somebody. + +I can't pair it with +m beta because that's + +a self-contraction and +will get subtracted out. + +So I can pick any +one of these fours. + +As far as I'm concerned, +all four are the same, + +so I have a choice of four +as to which one of these four + +operators from u I connect to. + +So that 4 is one of +the numerical factors + +that ultimately we +have to take care of. + +Then, the two types +comes because the next m + +that I pick from o I +have two possibilities. + +I can connect it either with the +partner of the first one that + +also carries index +i or I can connect + +to one of the things that +carries the opposite index j. + +So let's call type 1 where +I make the choice that I + +connect to the partner. + +And once I do that, +then I am forced + +to connect these two together. + +Now, each one of these pairings +connects one of these averages. + +So I can write +down what that is. + +So the first one connected an +alpha to an i as far as indices + +were concerned. + +It connected q to q1, so I have +2 pi to the d a delta function + +q plus q1. + +And the variance +associated with that, + +which is t plus k q +squared, et cetera. + +The second pairing +connects a beta to an i. + +So that's a delta beta i. + +And it connects q prime to q2. + +And so the variance +associated with that + +is t plus k q prime +squared and so forth. + +And finally, the third pairing +connects j to itself j. + +So I will get a delta jj. + +And then I have 2 pi to the d. + +q3 to minus q1 +minus q2 minus q3. + +So I will get minus +q1 minus q2, and then + +I have t plus, say, k +q3 squared and so forth. + +Now, what I am supposed to +do is at the next stage, + +I have to sum over indices i and +j and integrate over q1 q2 q3. + +So when I do that, +what do I get? + +There is an overall +factor of minus u. + +Let's do the indices. + +When I sum over i, delta +alpha i delta beta i + +becomes-- actually, let +me put the factor of 4 + +before I forget it. + +There is a factor +of 4 numerically. + +Delta alpha i delta beta i will +give me a delta alpha beta. + +When I integrate over +q1, q1 is set to minus q. + +So this after the +integration becomes q. + +When I integrate +over q2, the delta + +function q2 forces +minus q2 to be q prime. + +And through the process, two of +these factors of 2 pi to the d + +disappear. + +So what I'm left with +is 2 pi to the d. + +This delta function now +involves q plus q prime. + +And then in the denominator, +I have this factor of t + +plus k q squared. + +I have t plus k q prime squared. + +Although, q prime squared +and q squared are the same. + +I could have collapsed +these things together. + +I have one integration +left over q3. + +And these two +factors went outside + +the integral [INAUDIBLE] +independent q3. + +The only thing +that depends on q3 + +is t plus k q3 +squared and so forth. + +So that was easy. + +AUDIENCE: I have a question. + +PROFESSOR: Yes. + +AUDIENCE: If you're summing +over j, won't you get an n? + +PROFESSOR: Thank you very much. + +I forgot the delta jj. + +Summing over j, I will +get a factor of n. + +So what I had written +here as 4 should be 4n. + +Yes. + +AUDIENCE: This may be a +question too far back. + +But when you write a correlation +between two different m's, + +why do you write +delta function of q + +plus q prime instead +of q minus q prime? + +PROFESSOR: OK. + +Again, go back all +the way to here + +when we were doing +the Gaussian integral. + +I will have for +the first one, q1. + +For the second m, +I will write q2. + +So when I Fourier +transform this term, + +I will have e to the +i q1 plus q2 dot x. + +And then when I +integrate over x, + +I will get a delta +function q1 plus q2. + +So that's why I write all +of these as absolute value + +squared because I +could have written this + +as m of q m of minus q, but +I realized that m of minus q + +is the complex +conjugate of m of q. + +So all of these are +absolute values squared. + +Now, the second class of +contraction is-- again, + +write the same thing, m alpha of +q m beta of q prime m i of q1 m + +i of q2, mj of q3 mj of +minus q1 minus q2 minus q3. + +The first step is the same. + +I pick m alpha of q and I +have no choice but to pick + +one of the four +possibilities that I have + +for the operators +that appear in u. + +But for the second +one, previously I + +chose to connect it +to something that + +was carrying the same index. + +Now I choose to +carry it to something + +that carries the other +index, j in this case. + +And there are two things +that carry index j, + +so I have two choices there. + +And then I have the remaining +two have to be connected. + +Yes? + +AUDIENCE: Just going +back a little bit. + +Are you assuming that +your integral over q3 + +converges because you're +only integrating over + +the [INAUDIBLE] zone? + +PROFESSOR: Yes. + +AUDIENCE: OK. + +PROFESSOR: That's right. + +Any time I see a +divergent integral, + +I have a reason to +go back to my physics + +and see why physics +will avoid infinities. + +And in this case, because +all of my theories + +have an underlying length +scale associated with them + +and there is an +associated maximum value + +that I can go in Fourier space. + +The only possible +singularities that I + +want to get are coming +from q goes to 0. + +And again, if I really want +to physically cut that off, + +I would put the +size of the system. + +But I'm interested in systems +that become infinite in size. + +So the first term for this +way of contracting things + +is as follows. + +There are eight such terms. + +I should have really +put the four here. + +There are eight such +types of contractions. + +Then I have a delta alpha +i 2 pi to the d delta + +function q plus q1 divided by t +plus k q squared and so forth. + +The first contraction is +exactly the same as before. + +The next contraction I connect +i to j and q prime to q3. + +So I have a delta beta j 2 +pi to the d delta function q + +prime going to q3 divided +by t plus k q prime squared + +and so forth. + +And the last contraction +connects an i to a j. + +Delta ij. + +I have 2 pi to the d. + +Connecting q2 to minus +q1 minus q2 minus q3 + +will give me a delta function +which is minus q1 minus q3. + +And then I have t plus k-- I +guess in this case-- q2 squared + +and so forth. + +So once more sum ij. + +Integrate q1 q2 q3 and +let's see what happens. + +So again, it's a term that +is proportional to minus u. + +The numerical coefficient +that it carries is 8. + +And there is no n here +because when I sum over i, + +you can see that j is set +to be the same as alpha. + +Then when I sum over j, I set +alpha to be the same as beta. + +So there is just a +delta alpha beta. + +When I integrate over +q1, q1 is set to minus q. + +q3 is set to minus q prime. + +So this factor becomes the +same as q plus q prime. + +And the two variances, +which are in fact the same, + +I can continue to write +as separate entities + +but they're really +the same thing. + +And then the one +integral that is + +left-- I did q1 and Q3-- +it's the integral over q2, + +2 pi to the d 1 over t plus +K q2 squared and so forth. + +It is, in fact, exactly +the same integral + +as before, except that the +name of the dummy integration + +variable has changed from +q2 to q3, or q3 to q2. + +So we have calculated m +alpha of q m beta of q prime + +to the lowest order in +perturbation theory. + +To the first order, what I +had was a delta alpha beta 2 + +pi to the d delta function +q plus q prime divided by t + +plus k q squared. + +Now, note that all +of these factors + +are present in the +two terms that I + +had calculated as corrections. + +So I can factor this +out and write it + +as the correction as 1 +plus or minus something. + +It is proportional to u. + +The coefficient is +4n plus 8, which + +I will write as 4 n plus 2. + +I took out one factor +of t plus k q squared. + +There is one factor +that's will be remaining. + +Therefore, t plus k q squared. + +And then I have one +integration over some variable. + +Let's call it k. + +It doesn't matter what I call +the integration variable. + +1 over t plus k, k +squared, and so forth. + +And presumably, there will +be higher-order terms. + +Now again, I did the +calculation specifically + +for the Landau-Ginzburg, +but the procedure you + +would have been able to +do for any field theory. + +You could have +started with a part + +that you can solve +exactly and then + +look at perturbations +and corrections. + +Now, there is, in +fact, a reason why + +this correction +that we calculated + +had exactly the same +structure of delta functions + +as the original one. + +And why I anticipate that +higher-order terms, if I were + +to calculate, will +preserve that structure. + +And the reason has to +do with symmetries. + +Because quite generally, I +can write for anything-- m + +alpha m beta of q prime without +doing perturbation theory. + +Again, let's remember +m alphas of q + +are going to be related to +m of x by inverse Fourier + +transformation. + +So m alpha of q I can write +an integral d dx e to the-- I + +guess by that convention, it +has to be minus i q dot x. + +m alpha of x. + +And again, m beta +of q prime I can + +write as minus i q +prime dot x prime. + +And I integrate +also over an x prime + +of m alpha of x m +beta of x prime. + +Now, these are evaluated in +real space as opposed to Fourier + +space. + +And the average goes over here. + +At this stage, I +don't say anything + +about perturbation theory, +Gaussian, et cetera. + +What I expect is that +this is a function, + +that in a system that has +translational symmetry, only + +depends on x minus x prime. + +m beta. + +Furthermore, in a system that +has rotational symmetry that + +is not spontaneously +broken, that + +is approaching from the +high temperature side, + +then just rotational +symmetry forces you + +that-- the only +tensor that you have + +has to be proportional +to delta alpha beta. + +So I can pick some particular +component-- let's say m1-- + +and I can write it +in this fashion. + +So the rotational symmetry +explains the delta alpha beta. + +Now, knowing that the function +that I'm integrating over two + +variables actually only depends +on the relative position + +means that I can re-express +this in terms of the relative + +and center of mass coordinates. + +So I can express +that expression as e + +to the minus i q minus q +prime x minus x prime over 2. + +And then I will +write it as minus i + +q plus q prime x +plus x prime over 2. + +If you expand those, you will +see that all of the cross terms + +will vanish and I will get q +dot x and q prime dot x prime. + +Yes. + +AUDIENCE: [INAUDIBLE]? + +PROFESSOR: Yes. + +Thank you. + +So now I can change +integration variables + +to the relative coordinate and +the center of mass coordinate + +rather than integrating +over x and x prime. + +The integration over the +center of mass, the x plus x + +prime variable, couples +to q plus q prime. + +So it will immediately +tell me that the answer has + +to be proportional +to q plus q prime. + +I had already established that +there is a delta alpha beta. + +So the only thing that is +left is the integration + +over the relative coordinate +of e to the minus i + +some q-- either one of them. + +q dot r. + +Since q prime is minus q, +I can replace it with e + +to the i q dot the +relative coordinate. + +m1 of r m1 of 0. + +So that's why for a system +that has translational symmetry + +and rotational +symmetry, this structure + +of the delta functions +is really imposed + +for this type of +expectation value. + +Naturally, perturbation +theory has to obey that. + +But then, this is a quantity +that we had encountered before. + +If you recall when +we were scattering + +light out of the +system, the amplitude + +of something that was +scattered was proportional + +to the Fourier transform of +the correlation function. + +And furthermore, +in the limit where + +S is evaluated for q equal +to 0, what we are doing + +is we're essentially integrating +the correlation function. + +We've seen that the integrals +of correlation function + +correspond to the +susceptibilities. + +So you may have thought +that what I was calculating + +was a two-point correlation +function in perturbation + +theory. + +But what I was +actually leading up to + +is to know what the +result is for scattering + +from this theory. + +And in some limit +of it, I've also + +calculated what the +susceptibility is, + +how the susceptibility +is corrected. + +And again, if you recall +the typical structure + +that people see for +S of q is that S of q + +is something like 1 over +something like this. + +This is the +Lorentzian line shapes + +that we had in scattering. + +And clearly, the +Lorentzian line shape + +is obtained by Fourier +transformation and expectation + +values of these +expansions that we make. + +So it kind of makes +sense that rather + +than looking at this quantity, +I should look at its inverse. + +So I have calculated +s of q, which + +is the formula that +I have up there. + +So this whole thing +here is S of q. + +If I calculate its +inverse, what do I get? + +First of all, I +have to invert this. + +I have t plus k q squared, which +is what would have given me + +the Lorentzian if I +were to invert it. + +And now we have found the +correction to the Lorentzian + +if you like, which +is this object raised + +to the power of minus 1. + +But recall that I've +only calculated things + +to lowest order in u. + +So whenever I see something +and I'm inverting it + +just like I did +over here, I better + +be consistent to order of u. + +So to order of u, I can take +this thing from the numerator, + +bring it to the num-- +from denominator + +to numerator at the expense +of just changing the sign. + +Order of u squared +that we haven't really + +bothered to calculate. + +So now it's nice because you +can see that when I expand this, + +this factor will +cancel that factor. + +So the inverse has the +structure that we would like. + +It is t plus something +that is a constant, + +doesn't depend on +q, 4 n plus 2 u. + +Well, actually, no. + +Yeah. + +Because this denominator +gets canceled. + +I will get 4 n plus 2 +u integral over k 2 pi + +to the d 1 over t plus k +k squared and so forth. + +And then I have my k q squared. + +And presumably, I will +have higher-order terms + +both in u and higher +powers of q, et cetera. + +And in particular, the +inverse of the susceptibility + +is simply the first part. + +Forget about the k q squared. + +So the inverse of +susceptibility is + +t plus 4 n plus 2 u integral +d dk 2 pi to the d 1 over t + +plus k k squared and so forth. + +Plus order of things +that we haven't computed. + +So why is it interesting +to look at susceptibility? + +Because susceptibility is +one of the quantities-- + +it always has to be positive-- +that we were associating + +previously with +singular behavior. + +And in the absence of the +perturbative correction + +from the Gaussian, +the susceptibility + +we calculated many times. + +It was simply 1 over t. + +If I had added a +field, the field h + +would have changed +the free energy + +by an amount that would be +h squared over 2t as we saw. + +Take two derivatives, +I will get 1 + +over t for the susceptibility. + +So the 0 order sustainability +that I will indicate by chi sub + +0 was something that was +diverging at t equals to 0. + +And we were identifying +the critical exponent + +of the divergence as +gamma equals to 1. + +So here, I would have +added gamma 0 equals to 1. + +Because of the +linear divergence-- + +and the linear divergence +can be traced back + +to the linearity +of the vanishing + +of the inverse susceptibility +at temperature. + +Now, let's see whether we +have calculated a correction + +to gamma. + +Well, the first +thing that you notice + +that if I evaluated the new chi +inverse at 0, all I need to do + +is to put 0 in this formula. + +I will get 4 n plus 2 u. + +This integral d dk 2 pi to +the d 1 over k k squared. + +I set t equals to 0 here. + +Now this is, indeed, an integral +that if I integrate all the ay + +to infinity would diverge on me. + +I have to put an upper cutoff. + +It's a simple integral. + +I can write it as +integral 0 to lambda dk + +k to the d minus 1 with some +surface of a d dimensional + +sphere. + +I have this 2 pi +to the d out front + +and I have a k squared here. + +I can put the k out here. + +So you can see that this is an +integral that's just a power. + +I can simply do that. + +The answer ultimately will be +4 n plus 2 u Sd 2 pi to the d. + +There is a factor of 1 over +k that comes into play. + +The integral of +this will give me + +the upper cutoff to the d +minus 2 divided by d minus 2. + +So what we find is that the +corrected susceptibility + +to lowest order does not +diverge at t equals to 0. + +Its inverse is a finite value. + +So actually, you +can see that I've + +added something positive +to the denominator + +so the value of susceptibility +is always reduced. + +So what does that mean? + +Does that mean that the +susceptibility does not + +have a singularity anymore? + +The answer is no. + +It's just that the location of +the singularity has changed. + +The presence of +u m to the fourth + +gives some additional stiffness +that you have to overcome. + +t equals to 0 is not +sufficient for you. + +You have to go to +some other point tc. + +So I expect that this +thing will actually + +diverge at a new point +tc that is negative. + +And if it diverges, then +its inverse will be 0. + +So I have to solve the +equation tc plus 4 n + +plus 2 u integral d dk 2 pi +to the d of 1 over tc plus k + +k squared and so forth. + +So this seems like an implicit +[INAUDIBLE] equation in tc + +because I have to evaluate the +integral that depends on tc, + +and then have to set +that function to 0. + +But again, we have calculated +things only correctly + +to order of u. + +And you can see already that +tc is proportional to u. + +So this answer here is something +that is order of u presumably. + +And a u compared +to the u out front + +will give me a correction +that is order of u squared. + +So I can ignore this +thing that is over here. + +So to order of u, I know +that tc is actually minus + +what I had calculated before. + +So I get that tc is +minus this 4 n plus 2 u k + +Sd lambda to the d minus +2 2 pi to the d d minus 2. + +It doesn't matter what it is, +it's some non-universal value. + +Point is that, again, +the location of the phase + +transition certainly will +depend on the parameters + +that you put in your theory. + +We readjusted our theory +by putting m to the fourth. + +And certainly, that will change +the location of the transition. + +So this is what we found. + +The location of the +transition is not universal. + +However, we kind +of hope and expect + +that the singularity, the +divergence of susceptibility + +has a form that is universal. + +There is an exponent that +is characteristic of that. + +So asking the question of +how these corrected chi + +divergence diverges +at this tc is the same + +as asking the question of how +its inverse vanishes at tc. + +So what I am interested +is to find out + +what the behavior of chi inverse +is in the vicinity of the point + +that it goes to 0. + +So basically, what +this singularity is. + +This is, of course, 0. + +By definition, chi +inverse of tc is 0. + +So I am asking how chi vanishes +its inverse when I approach tc. + +So I have the formula for +chi once I substitute t, + +once I substitute tc +and I subtract them. + +To lowest order I +have t minus tc. + +To next order, I have this 4 u +n plus 2 integral over k 2 pi + +to the d. + +I have for chi inverse of t 1 +over t plus k k squared minus 1 + +over tc plus k k squared. + +And terms that I +have not calculated + +are certainly +order of u squared. + +Now, you can see that +if I combine these two + +into the same denominator +that is the product, + +in the numerator I will +get a factor of t minus tc. + +The k q squareds cancel. + +So I can factor out this t +minus tc between the two terms. + +Both terms vanish +at t equals to tc. + +And then I can look at +what the correction is + +to one, just like I did before. + +The correction is going +to-- actually, this + +will give me tc minus t, +so I will have a minus 4 u + +n plus 2 integral +d dk 2 pi to the d. + +The product of two of these +factors, t plus k-- tc plus k k + +squared t plus k k squared, +and then order of u squared. + +OK? + +Happy with that? + +Now again, this tc we've +calculated is order of u. + +And consistently, to calculate +things to order of u, + +I can drop that. + +And again, consistently to +doing things to order of u, + +I can add a tc here. + +And that's also a correction +that is order of u. + +And this answer +would not change. + +The justification of +why I choose to do that + +will become apparent +shortly, but it's consistent + +that this is left. + +So what I find at +this stage is that I + +need to evaluate an +integral of this form. + +And again, with all +of these integrals, + +we better take a look as to +what the most significant + +contribution to the integral is. + +And clearly, if I +look at k goes to 0, + +there are various +factors out there + +that as long as t +minus tc is positive, + +I will have no worries +because this k squared + +will be killed off +by factors of k + +to the d minus 1 in +dimensions above 2. + +But if I go to large +k-values, I find + +that large k-values, +the singularity + +is governed by k to +the power of d minus 4. + +So as long as I'm +dealing with things + +that have some upper +cutoff, I don't + +have to worry about it even +in dimensions greater than 4. + +In dimensions +greater than 4, what + +happens is that the +integral is going + +to be dominated by the +largest values of k. + +But those largest values of +k will be cutoff by lambda. + +The answer ultimately +will be proportional to 1 + +over k squared, and then k +to the power of d minus 4 + +replaced by lambda +to the d minus 4-- + +various overall coefficient +of d minus 4 or whatever. + +It doesn't matter. + +On the other hand, if you go +to dimensions less than 4-- + +again, larger than +2, but I won't + +write that for the time being-- +then the behavior at large k + +is perfectly convergent. + +So you are integrating +a function that goes up, + +comes down. + +You can extend the integration +all the way to infinity, + +end up with a definite integral. + +We can rescale all +of our factors of k + +to find out what that definite +integral is dependent on. + +And essentially, what it does +is it replaces this lambda + +with the characteristic value +of k that corresponds roughly + +to the maximum. + +And that's going to +occur at something + +like t minus tc over +k to the power of 1/2. + +So I will get d minus 4 over 2. + +There is some overall definite +integral that I have to do, + +which will give me some +numerical coefficient. + +But at this time, +let's forget about + +the numerical coefficient. + +Let's see what the structure is. + +So the structure then +is that chi inverse + +of t, the singularity +that it has + +is t minus tc to the 0 order. + +Same thing as you would have +predicted for the Gaussian. + +And then we have a +correction, which + +is this minus something that +goes after all of these things + +with some coefficient. + +I don't care what +that coefficient is. + +u n plus 2 divided by k squared. + +And then multiplied by lambda +to the power of d minus 4, + +or t minus tc over k to the +power of d minus 4 over 2. + +And then presumably, +higher-order terms. + +And whether you have +the top or the bottom + +will depend on d greater +than 4 or d less than 4. + +So you see the problem. + +If I'm above four +dimensions, this term + +is governed by the upper cutoff. + +But the upper cutoff +is just some constant. + +So all that happens +is that the dependence + +remains as being +proportional to t minus tc. + +The overall amplitude +is corrected + +by something that depends on u. + +You are not worried. + +You say that the leading +singularity is the same thing + +as I had before. + +Gamma will stay to be 1. + +I try to do that in less +than four dimensions + +and I find that as I approach +tc, the correction that I had + +actually itself +becomes divergent. + +So now I have to throw out +my entire perturbation theory + +because I thought I was making +an expansion in quantity + +that I can make +sufficiently small. + +So in usual perturbation +theory, you say + +choose epsilon less than 10 +to the minus 100, or whatever, + +and then things will +be small correction + +to what you had at 0 order. + +Here, I can choose my u +to be as small as I like. + +Once I approach tc, the +correction will blow up. + +So this is called a divergent +perturbation theory. + +Yes. + +AUDIENCE: So could we have +known a priori that we couldn't + +get a correction to gamma +from the perturbation theory + +because the only way +for gamma to change + +is for the correction +to have a divergence? + +PROFESSOR: You are presuming +that that's what happens. + +So indeed, if you +knew that there + +is a divergence with an exponent +that is larger than gamma, + +you probably could +have guessed that you + +wouldn't get it this way. + +Let's say that we are choosing +to proceed mathematically + +without prior knowledge of what +the experimentalists have told + +us, then we can +discover it this way. + +AUDIENCE: I was +thinking if you're + +looking for how gamma changes +due to the higher-order things, + +if we found that our +perturbation diverged + +with a lower +exponent than gamma, + +then the leading one +would still be there, + +original gamma would be gone. + +PROFESSOR: Yes. + +AUDIENCE: And then +if it's higher, + +then we have the same problem. + +PROFESSOR: That's right. + +So the problem that +we have is actually + +to somehow make sense of this +type of perturbation theory. + +And as you say, it's correct. + +We could have actually guessed. + +And I'll give you another +reason why the perturbation + +theory would not have worked. + +But the only thing +that we can really do + +is perturbation +theory, so we have + +to be clever and figure +out a way of making sense + +of this perturbation theory, +which we will do by combining + +it with the normalization group. + +But a better way or another +way to have seen maybe + +why this does not work is +good old-fashioned dimensional + +analysis. + +I have within the exponent of +the weight that I wrote down + +terms that are of this formula, +t m squared k gradient of m + +squared u m to the +fourth and so forth. + +Since whatever is in +the exponent should + +be dimensionless-- I usually +write beta H for example-- + +we know that this t +has some dimension. + +Square the dimension of m +multiplied by length to the d. + +This should be dimensionless. + +Similarly, k m squared again. + +Because of the gradient +l to the d minus 2, + +that combination should +be dimensionless. + +And my u m to the fourth l to +the d should be dimensionless. + +So we can get rid of the +dimensions of m by dividing, + +let's say, u m to the fourth +with the square of k m squared. + +So we can immediately +see that u divided by k + +squared, I get rid of +the dimensions of m. + +l to the power of d +l to the 2d minus 4, + +giving me l to the 4 +minus d is dimensionless. + +So any perturbation theory that +I write down ultimately where + +I have some quantity x, +which is at 0 order 1, + +and then I want to make a +correction where u appears, + +I should have +something, u over k + +squared, and then some power of +length to make the dimensions + +work out. + +So what lengths do I +have available to me? + +One length that I have is +my microscopic length a. + +So I could have put here a +to the power of 4 minus d. + +But there is also +an emergent length + +in the problem, which is +the correlation length. + +And there is no reason why +the dimensionless form that + +involves the correlation +length should not appear. + +And indeed, what we have +over here to 0 order, + +our correlation length had +the exponent 1/2 divergence. + +So this is really the 0 +order correlation length + +that is raised to the +power of 4 minus d. + +So even before doing +the calculation, + +we could have guessed +on dimensional ground + +that it is quite possible +that we are expanding in u, + +we think. + +But at the end of the day, +we are expanding in u c + +to the power of 4 minus d. + +And there is no way that that's +a small quantity on approaching + +the phase transition. + +And that hit us on +the face and also is + +the reason why I replaced this +t over here with t minus tc + +because the only place where I +expect singularities to emerge + +in any of these +expansions is at tc. + +I arranged things so they would +appear at the right place. + +So should we throw out +perturbation theory completely + +since the only +thing that we can do + +is really perturbation theory? + +Well, we have to +be clever about it. + +And that's what we +will do next lectures. \ No newline at end of file diff --git a/0OX-DkYPB3c.txt b/0OX-DkYPB3c.txt new file mode 100644 index 0000000000000000000000000000000000000000..edb4ac12ba30422b68f366499e686d96d502db34 --- /dev/null +++ b/0OX-DkYPB3c.txt @@ -0,0 +1,228 @@ +One of the biggest and slowest circuits in +an arithmetic and logic unit is the multiplier. + +We'll start by developing a straightforward +implementation and then, in the next section, + +look into tradeoffs to make it either smaller +or faster. + +Here's the multiplication operation for two +unsigned 4-bit operands broken down into its + +component operations. + +This is exactly how we learned to do it in +primary school. + +We take each digit of the multiplier (the +B operand) and use our memorized multiplication + +tables to multiply it with each digit of the +multiplicand (the A operand), + +dealing with any carries into the next column +as we process the multiplicand right-to-left. + +The output from this step is called a partial +product and then we repeat the step for the + +remaining bits of the multiplier. + +Each partial product is shifted one digit +to the left, reflecting the increasing weight + +of the multiplier digits. + +In our case the digits are just single bits, +i.e., they're 0 or 1 and the multiplication + +table is pretty simple! + +In fact, the 1-bit-by-1-bit binary multiplication +circuit is just a 2-input AND gate. + +And look Mom, no carries! + +The partial products are N bits wide since +there are no carries. + +If the multiplier has M bits, there will be +M partial products. + +And when we add the partial products together, +we'll get an N+M bit result if we account + +for the possible carry-out from the high-order +bit. + +The easy part of the multiplication is forming +the partial products - it just requires some + +AND gates. + +The more expensive operation is adding together +the M N-bit partial products. + +Here's the schematic for the combinational +logic needed to implement the 4x4 multiplication, + +which would be easy to extend for larger multipliers +(we'd need more rows) or larger multiplicands + +(we'd need more columns). + +The M*N 2-input AND gates compute the bits +of the M partial products. + +The adder modules add the current row's partial +product with the sum of the partial products + +from the earlier rows. + +Actually there are two types of adder modules. + +The full adder is used when the modules needs +three inputs. + +The simpler half adder is used when only two +inputs are needed. + +The longest path through this circuit takes +a moment to figure out. + +Information is always moving either down a +row or left to the adjacent column. + +Since there are M rows and, in any particular +row, N columns, there are at most N+M modules + +along any path from input to output. + +So the latency is order N, since M and N differ +by just some constant factor. + +Since this is a combinational circuit, the +throughput is just 1/latency. + +And the total amount of hardware is order +N^2. + +In the next section, we'll investigate how +to reduce the hardware costs, or, separately, + +how to increase the throughput. + +But before we do that, let's take a moment +to see how the circuit would change if the + +operands were two's complement integers instead +of unsigned integers. + +With a two's complement multiplier and multiplicand, +the high-order bit of each has negative weight. + +So when adding together the partial products, +we'll need to sign-extend each of the N-bit + +partial products to the full N+M-bit width +of the addition. + +This will ensure that a negative partial product +is properly treated when doing the addition. + +And, of course, since the high-order bit of +the multiplier has a negative weight, we'd + +subtract instead of add the last partial product. + +Now for the clever bit. + +We'll add 1's to various of the columns and +then subtract them later, with the goal of + +eliminating all the extra additions caused +by the sign-extension. + +We'll also rewrite the subtraction of the +last partial product as first complementing + +the partial product and then adding 1. + +This is all a bit mysterious but… + +Here in step 3 we see the effect of all the +step 2 machinations. + +Let's look at the high order bit of the first +partial product X3Y0. + +If that partial product is non-negative, X3Y0 +is a 0, so all the sign-extension bits are + +0 and can be removed. + +The effect of adding a 1 in that position +is to simply complement X3Y0. + +On the other hand, if that partial product +is negative, X3Y0 is 1, and all the sign-extension + +bits are 1. + +Now when we add a 1 in that position, we complement +the X3Y0 bit back to 0, but we also get a + +carry-out. + +When that's added to the first sign-extension +bit (which is itself a 1), we get zero with + +another carry-out. + +And so on, with all the sign-extension bits +eventually getting flipped to 0 as the carry + +ripples to the end. + +Again the net effect of adding a 1 in that +position is to simply complement X3Y0. + +We do the same for all the other sign-extended +partial products, leaving us with the results + +shown here. + +In the final step we do a bit of arithmetic +on the remaining constants to end up with + +this table of work to be done. + +Somewhat to our surprise, this isn't much +different than the original table for the + +unsigned multiplication. + +There are a few partial product bits that +need to be complemented, and two 1-bits that + +need to be added to particular columns. + +The resulting circuitry is shown here. + +We've changed some of the AND gates to NAND +gates to perform the necessary complements. + +And we've changed the logic necessary to deal +with the two 1-bits that needed to be added + +in. + +The colored elements show the changes made +from the original unsigned multiplier circuitry. + +Basically, the circuit for multiplying two's +complement operands has the same latency, + +throughput and hardware costs as the original +circuitry. \ No newline at end of file diff --git a/0UFwGJe6ubg.txt b/0UFwGJe6ubg.txt new file mode 100644 index 0000000000000000000000000000000000000000..15b7ef563766db52449152cc969bd69260382ce3 --- /dev/null +++ b/0UFwGJe6ubg.txt @@ -0,0 +1,12499 @@ +align:start position:0% + +so last time we talked about + + align:start position:0% +so last time we talked about + + + align:start position:0% +so last time we talked about +medicine does and today I want to take a + + align:start position:0% +medicine does and today I want to take a + + + align:start position:0% +medicine does and today I want to take a +deep dive into medical data and I'm + + align:start position:0% +deep dive into medical data and I'm + + + align:start position:0% +deep dive into medical data and I'm +going to use as examples a lot of stuff + + align:start position:0% +going to use as examples a lot of stuff + + + align:start position:0% +going to use as examples a lot of stuff +from the mimic database which is one of + + align:start position:0% +from the mimic database which is one of + + + align:start position:0% +from the mimic database which is one of +the databases that we're going to be + + align:start position:0% +the databases that we're going to be + + + align:start position:0% +the databases that we're going to be +using in this class some of you are + + align:start position:0% +using in this class some of you are + + + align:start position:0% +using in this class some of you are +probably familiar with it and some of + + align:start position:0% +probably familiar with it and some of + + + align:start position:0% +probably familiar with it and some of +you or not and there are I hope some + + align:start position:0% +you or not and there are I hope some + + + align:start position:0% +you or not and there are I hope some +takeaway lessons from this discussion so + + align:start position:0% +takeaway lessons from this discussion so + + + align:start position:0% +takeaway lessons from this discussion so +for example a few years ago when mimic 3 + + align:start position:0% +for example a few years ago when mimic 3 + + + align:start position:0% +for example a few years ago when mimic 3 +was about to be released I was playing + + align:start position:0% +was about to be released I was playing + + + align:start position:0% +was about to be released I was playing +with the data and I looked at the + + align:start position:0% +with the data and I looked at the + + + align:start position:0% +with the data and I looked at the +distribution of heart rates in the care + + align:start position:0% +distribution of heart rates in the care + + + align:start position:0% +distribution of heart rates in the care +view part of the database so mimic for + + align:start position:0% +view part of the database so mimic for + + + align:start position:0% +view part of the database so mimic for +those of you who don't know has + + align:start position:0% +those of you who don't know has + + + align:start position:0% +those of you who don't know has +intensive care data from about 60 + + align:start position:0% +intensive care data from about 60 + + + align:start position:0% +intensive care data from about 60 +something thousand admissions to + + align:start position:0% +something thousand admissions to + + + align:start position:0% +something thousand admissions to +intensive care units at the Beth Israel + + align:start position:0% +intensive care units at the Beth Israel + + + align:start position:0% +intensive care units at the Beth Israel +Deaconess Medical Center over a period + + align:start position:0% +Deaconess Medical Center over a period + + + align:start position:0% +Deaconess Medical Center over a period +of about twelve years and one of the + + align:start position:0% +of about twelve years and one of the + + + align:start position:0% +of about twelve years and one of the +technical difficulties that we + + align:start position:0% +technical difficulties that we + + + align:start position:0% +technical difficulties that we +encountered is that in the middle of + + align:start position:0% +encountered is that in the middle of + + + align:start position:0% +encountered is that in the middle of +that time period the hospital shifted + + align:start position:0% +that time period the hospital shifted + + + align:start position:0% +that time period the hospital shifted +from one information system that they + + align:start position:0% +from one information system that they + + + align:start position:0% +from one information system that they +used in their intensive care unit to + + align:start position:0% +used in their intensive care unit to + + + align:start position:0% +used in their intensive care unit to +another care view as the old one meta + + align:start position:0% +another care view as the old one meta + + + align:start position:0% +another care view as the old one meta +vision is the new one and of course + + align:start position:0% +vision is the new one and of course + + + align:start position:0% +vision is the new one and of course +they're not exactly compatible so we'll + + align:start position:0% +they're not exactly compatible so we'll + + + align:start position:0% +they're not exactly compatible so we'll +say that we'll see some examples of that + + align:start position:0% +say that we'll see some examples of that + + + align:start position:0% +say that we'll see some examples of that +so this is the old data so this is from + + align:start position:0% +so this is the old data so this is from + + + align:start position:0% +so this is the old data so this is from +care view and you look at that and say + + align:start position:0% +care view and you look at that and say + + + align:start position:0% +care view and you look at that and say +well heart rates range from you know 40 + + align:start position:0% +well heart rates range from you know 40 + + + align:start position:0% +well heart rates range from you know 40 +to 200 roughly which is okay but then + + align:start position:0% +to 200 roughly which is okay but then + + + align:start position:0% +to 200 roughly which is okay but then +there's this funny thing there are two + + align:start position:0% +there's this funny thing there are two + + + align:start position:0% +there's this funny thing there are two +peaks so where if ever do you see two + + align:start position:0% +peaks so where if ever do you see two + + + align:start position:0% +peaks so where if ever do you see two +peaks in physiological data not typical + + align:start position:0% +peaks in physiological data not typical + + + align:start position:0% +peaks in physiological data not typical +and so my initial reaction was + + align:start position:0% + + + + align:start position:0% + +so then I looked a little little closer + + align:start position:0% +so then I looked a little little closer + + + align:start position:0% +so then I looked a little little closer +and I said hmm + + align:start position:0% +and I said hmm + + + align:start position:0% +and I said hmm +what are the heart rates look like from + + align:start position:0% +what are the heart rates look like from + + + align:start position:0% +what are the heart rates look like from +these two systems and if you look in + + align:start position:0% +these two systems and if you look in + + + align:start position:0% +these two systems and if you look in +care of you you see the picture that I + + align:start position:0% +care of you you see the picture that I + + + align:start position:0% +care of you you see the picture that I +just showed you and if you look in meta + + align:start position:0% +just showed you and if you look in meta + + + align:start position:0% +just showed you and if you look in meta +vision you see this other picture which + + align:start position:0% +vision you see this other picture which + + + align:start position:0% +vision you see this other picture which +looks more like what you would normally + + align:start position:0% +looks more like what you would normally + + + align:start position:0% +looks more like what you would normally +expect and so I'm sitting there + + align:start position:0% +expect and so I'm sitting there + + + align:start position:0% +expect and so I'm sitting there +scratching my head going okay there must + + align:start position:0% +scratching my head going okay there must + + + align:start position:0% +scratching my head going okay there must +be some difference between these it's + + align:start position:0% +be some difference between these it's + + + align:start position:0% +be some difference between these it's +not that simultaneous with the + + align:start position:0% +not that simultaneous with the + + + align:start position:0% +not that simultaneous with the +switchover of the hospital from one + + align:start position:0% +switchover of the hospital from one + + + align:start position:0% +switchover of the hospital from one +information system to another physiology + + align:start position:0% +information system to another physiology + + + align:start position:0% +information system to another physiology +of people changed and all of a sudden + + align:start position:0% +of people changed and all of a sudden + + + align:start position:0% +of people changed and all of a sudden +some subset of people started having + + align:start position:0% +some subset of people started having + + + align:start position:0% +some subset of people started having +faster heart rates right but if you + + align:start position:0% +faster heart rates right but if you + + + align:start position:0% +faster heart rates right but if you +think about that what subset of people + + align:start position:0% +think about that what subset of people + + + align:start position:0% +think about that what subset of people +have faster heart rates yeah kids right + + align:start position:0% +have faster heart rates yeah kids right + + + align:start position:0% +have faster heart rates yeah kids right +so I said hmm interesting so anyway if + + align:start position:0% +so I said hmm interesting so anyway if + + + align:start position:0% +so I said hmm interesting so anyway if +you look at the statistics you see that + + align:start position:0% +you look at the statistics you see that + + + align:start position:0% +you look at the statistics you see that +the mean heart rate in care view is a + + align:start position:0% +the mean heart rate in care view is a + + + align:start position:0% +the mean heart rate in care view is a +hundred and eight heart heart rate and + + align:start position:0% +hundred and eight heart heart rate and + + + align:start position:0% +hundred and eight heart heart rate and +meta vision is is 87 + + align:start position:0% +meta vision is is 87 + + + align:start position:0% +meta vision is is 87 +but of course means are not that + + align:start position:0% +but of course means are not that + + + align:start position:0% +but of course means are not that +meaningful when you look at at these + + align:start position:0% +meaningful when you look at at these + + + align:start position:0% +meaningful when you look at at these +bimodal distributions so then I said + + align:start position:0% +bimodal distributions so then I said + + + align:start position:0% +bimodal distributions so then I said +well what if we just look at adults so + + align:start position:0% +well what if we just look at adults so + + + align:start position:0% +well what if we just look at adults so +we look at people from age greater than + + align:start position:0% +we look at people from age greater than + + + align:start position:0% +we look at people from age greater than +one up to age 90 and I'll say a word + + align:start position:0% +one up to age 90 and I'll say a word + + + align:start position:0% +one up to age 90 and I'll say a word +about that in a minute + + align:start position:0% +about that in a minute + + + align:start position:0% +about that in a minute +and I look at those two distributions + + align:start position:0% +and I look at those two distributions + + + align:start position:0% +and I look at those two distributions +they look pretty close they look pretty + + align:start position:0% +they look pretty close they look pretty + + + align:start position:0% +they look pretty close they look pretty +similar so that means that the number of + + align:start position:0% +similar so that means that the number of + + + align:start position:0% +similar so that means that the number of +patients of different ages in the adult + + align:start position:0% +patients of different ages in the adult + + + align:start position:0% +patients of different ages in the adult +group is similar in the two data sets + + align:start position:0% +group is similar in the two data sets + + + align:start position:0% +group is similar in the two data sets +but if I don't exclude the very young or + + align:start position:0% +but if I don't exclude the very young or + + + align:start position:0% +but if I don't exclude the very young or +the very old then I see this funny + + align:start position:0% +the very old then I see this funny + + + align:start position:0% +the very old then I see this funny +distribution where I have suppressed + + align:start position:0% +distribution where I have suppressed + + + align:start position:0% +distribution where I have suppressed +ages greater than 90 but not the young + + align:start position:0% +ages greater than 90 but not the young + + + align:start position:0% +ages greater than 90 but not the young +and what you see is that in care view + + align:start position:0% +and what you see is that in care view + + + align:start position:0% +and what you see is that in care view +there's this giant spike at age + + align:start position:0% +there's this giant spike at age + + + align:start position:0% +there's this giant spike at age +zero right so what happened at the + + align:start position:0% +zero right so what happened at the + + + align:start position:0% +zero right so what happened at the +hospital is that under the old system it + + align:start position:0% +hospital is that under the old system it + + + align:start position:0% +hospital is that under the old system it +was also being used in the NICU the + + align:start position:0% +was also being used in the NICU the + + + align:start position:0% +was also being used in the NICU the +neonatal intensive care unit the new + + align:start position:0% +neonatal intensive care unit the new + + + align:start position:0% +neonatal intensive care unit the new +system was not being used in the NICU + + align:start position:0% +system was not being used in the NICU + + + align:start position:0% +system was not being used in the NICU +and therefore they didn't capture data + + align:start position:0% +and therefore they didn't capture data + + + align:start position:0% +and therefore they didn't capture data +about babies all right and in fact if + + align:start position:0% +about babies all right and in fact if + + + align:start position:0% +about babies all right and in fact if +you look at age versus heart rate of the + + align:start position:0% +you look at age versus heart rate of the + + + align:start position:0% +you look at age versus heart rate of the +entire population you see two very + + align:start position:0% +entire population you see two very + + + align:start position:0% +entire population you see two very +peculiar things so here are the adults + + align:start position:0% +peculiar things so here are the adults + + + align:start position:0% +peculiar things so here are the adults +that we've been talking about and here + + align:start position:0% +that we've been talking about and here + + + align:start position:0% +that we've been talking about and here +are the babies and sure enough they have + + align:start position:0% +are the babies and sure enough they have + + + align:start position:0% +are the babies and sure enough they have +higher heart rates and then here are + + align:start position:0% +higher heart rates and then here are + + + align:start position:0% +higher heart rates and then here are +these 300 year old people oh wow I don't + + align:start position:0% +these 300 year old people oh wow I don't + + + align:start position:0% +these 300 year old people oh wow I don't +think I'm going to have a heart rate + + align:start position:0% +think I'm going to have a heart rate + + + align:start position:0% +think I'm going to have a heart rate +when I'm slow + + align:start position:0% +when I'm slow + + + align:start position:0% +when I'm slow +so who are those people anybody have a + + align:start position:0% +so who are those people anybody have a + + + align:start position:0% +so who are those people anybody have a +clue yeah sorry there are too many of + + align:start position:0% +clue yeah sorry there are too many of + + + align:start position:0% +clue yeah sorry there are too many of +them yeah entry errors is always a + + align:start position:0% +them yeah entry errors is always a + + + align:start position:0% +them yeah entry errors is always a +possibility but there's quite a few data + + align:start position:0% +possibility but there's quite a few data + + + align:start position:0% +possibility but there's quite a few data +points there yeah + + align:start position:0% + + + + align:start position:0% + +close it's not quite missing data so + + align:start position:0% +close it's not quite missing data so + + + align:start position:0% +close it's not quite missing data so +HIPAA the Health Insurance Portability + + align:start position:0% +HIPAA the Health Insurance Portability + + + align:start position:0% +HIPAA the Health Insurance Portability +and Accountability Act defines a set of + + align:start position:0% +and Accountability Act defines a set of + + + align:start position:0% +and Accountability Act defines a set of +criteria about protecting personal + + align:start position:0% +criteria about protecting personal + + + align:start position:0% +criteria about protecting personal +health information and one of the things + + align:start position:0% +health information and one of the things + + + align:start position:0% +health information and one of the things +you are not allowed to do is to specify + + align:start position:0% +you are not allowed to do is to specify + + + align:start position:0% +you are not allowed to do is to specify +the age of somebody who is 90 years old + + align:start position:0% +the age of somebody who is 90 years old + + + align:start position:0% +the age of somebody who is 90 years old +or older and the reason is because the + + align:start position:0% +or older and the reason is because the + + + align:start position:0% +or older and the reason is because the +number of 97 year olds is pretty small + + align:start position:0% +number of 97 year olds is pretty small + + + align:start position:0% +number of 97 year olds is pretty small +and so if I tell you that Willie is 97 + + align:start position:0% +and so if I tell you that Willie is 97 + + + align:start position:0% +and so if I tell you that Willie is 97 +years old then you're going to be able + + align:start position:0% +years old then you're going to be able + + + align:start position:0% +years old then you're going to be able +to pick them out of a population + + align:start position:0% +to pick them out of a population + + + align:start position:0% +to pick them out of a population +relatively easily and so it's prohibited + + align:start position:0% +relatively easily and so it's prohibited + + + align:start position:0% +relatively easily and so it's prohibited +to say that okay so as a result + + align:start position:0% +to say that okay so as a result + + + align:start position:0% +to say that okay so as a result +everybody who's 90 or older + + align:start position:0% +everybody who's 90 or older + + + align:start position:0% +everybody who's 90 or older +gets labeled as being 300 years old in + + align:start position:0% +gets labeled as being 300 years old in + + + align:start position:0% +gets labeled as being 300 years old in +the database it's an artifact right it's + + align:start position:0% +the database it's an artifact right it's + + + align:start position:0% +the database it's an artifact right it's +like back in + + align:start position:0% +like back in + + + align:start position:0% +like back in +very in my in my youth I worked as a + + align:start position:0% +very in my in my youth I worked as a + + + align:start position:0% +very in my in my youth I worked as a +computer programmer at a health sciences + + align:start position:0% +computer programmer at a health sciences + + + align:start position:0% +computer programmer at a health sciences +computing facility at UCLA and we used + + align:start position:0% +computing facility at UCLA and we used + + + align:start position:0% +computing facility at UCLA and we used +to have a convention that missing data + + align:start position:0% +to have a convention that missing data + + + align:start position:0% +to have a convention that missing data +was represented by nine nine nine nine + + align:start position:0% +was represented by nine nine nine nine + + + align:start position:0% +was represented by nine nine nine nine +nine okay and of course if you average + + align:start position:0% +nine okay and of course if you average + + + align:start position:0% +nine okay and of course if you average +that into a real data set you get + + align:start position:0% +that into a real data set you get + + + align:start position:0% +that into a real data set you get +garbage which people did regularly so + + align:start position:0% +garbage which people did regularly so + + + align:start position:0% +garbage which people did regularly so +there there are problems with this and + + align:start position:0% +there there are problems with this and + + + align:start position:0% +there there are problems with this and +we're running into one of those if you + + align:start position:0% +we're running into one of those if you + + + align:start position:0% +we're running into one of those if you +look at the at just the adults the two + + align:start position:0% +look at the at just the adults the two + + + align:start position:0% +look at the at just the adults the two +systems actually look very similar so + + align:start position:0% +systems actually look very similar so + + + align:start position:0% +systems actually look very similar so +the blue and red dots or the two systems + + align:start position:0% +the blue and red dots or the two systems + + + align:start position:0% +the blue and red dots or the two systems +and I've drawn the trend lines between + + align:start position:0% +and I've drawn the trend lines between + + + align:start position:0% +and I've drawn the trend lines between +them and you can see that they're very + + align:start position:0% +them and you can see that they're very + + + align:start position:0% +them and you can see that they're very +similar so it looks like as you get + + align:start position:0% +similar so it looks like as you get + + + align:start position:0% +similar so it looks like as you get +older your heart rate declines very + + align:start position:0% +older your heart rate declines very + + + align:start position:0% +older your heart rate declines very +slightly but it does so equally in the + + align:start position:0% +slightly but it does so equally in the + + + align:start position:0% +slightly but it does so equally in the +to date a bit datasets yeah well that's + + align:start position:0% +to date a bit datasets yeah well that's + + + align:start position:0% +to date a bit datasets yeah well that's +because the ages there are computed at + + align:start position:0% +because the ages there are computed at + + + align:start position:0% +because the ages there are computed at +the time that the heart rate is measured + + align:start position:0% +the time that the heart rate is measured + + + align:start position:0% +the time that the heart rate is measured +and so if you are 300 years old when you + + align:start position:0% +and so if you are 300 years old when you + + + align:start position:0% +and so if you are 300 years old when you +admitted to the hospital if you stay in + + align:start position:0% +admitted to the hospital if you stay in + + + align:start position:0% +admitted to the hospital if you stay in +the hospital for six months then you're + + align:start position:0% +the hospital for six months then you're + + + align:start position:0% +the hospital for six months then you're +300 and a half years old by the time of + + align:start position:0% +300 and a half years old by the time of + + + align:start position:0% +300 and a half years old by the time of +that measurement so that's why there are + + align:start position:0% +that measurement so that's why there are + + + align:start position:0% +that measurement so that's why there are +data points to the right of 300 yeah + + align:start position:0% +data points to the right of 300 yeah + + + align:start position:0% +data points to the right of 300 yeah +good good catch okay and then this is + + align:start position:0% +good good catch okay and then this is + + + align:start position:0% +good good catch okay and then this is +what the babies look like and of course + + align:start position:0% +what the babies look like and of course + + + align:start position:0% +what the babies look like and of course +they do have higher heart rates and here + + align:start position:0% +they do have higher heart rates and here + + + align:start position:0% +they do have higher heart rates and here +here are the oldsters so actually there + + align:start position:0% +here are the oldsters so actually there + + + align:start position:0% +here are the oldsters so actually there +are people out to 310 years old because + + align:start position:0% +are people out to 310 years old because + + + align:start position:0% +are people out to 310 years old because +maybe they were discharged from the + + align:start position:0% +maybe they were discharged from the + + + align:start position:0% +maybe they were discharged from the +hospital and then at age 100 they came + + align:start position:0% +hospital and then at age 100 they came + + + align:start position:0% +hospital and then at age 100 they came +back you know maybe there were 90 years + + align:start position:0% +back you know maybe there were 90 years + + + align:start position:0% +back you know maybe there were 90 years +old at the time they were initially + + align:start position:0% +old at the time they were initially + + + align:start position:0% +old at the time they were initially +admitted ten years later they came back + + align:start position:0% +admitted ten years later they came back + + + align:start position:0% +admitted ten years later they came back +and we recorded more data about them so + + align:start position:0% +and we recorded more data about them so + + + align:start position:0% +and we recorded more data about them so +this is all relative to to that 300 okay + + align:start position:0% +this is all relative to to that 300 okay + + + align:start position:0% +this is all relative to to that 300 okay +so that's just one example and the + + align:start position:0% +so that's just one example and the + + + align:start position:0% +so that's just one example and the +lesson there is be careful when you look + + align:start position:0% +lesson there is be careful when you look + + + align:start position:0% +lesson there is be careful when you look +at data because it can really easily + + align:start position:0% +at data because it can really easily + + + align:start position:0% +at data because it can really easily +fool you because there are all kinds of + + align:start position:0% +fool you because there are all kinds of + + + align:start position:0% +fool you because there are all kinds of +funny things about the way it's + + align:start position:0% +funny things about the way it's + + + align:start position:0% +funny things about the way it's +collected about these artefactual things + + align:start position:0% +collected about these artefactual things + + + align:start position:0% +collected about these artefactual things +like 300 + + align:start position:0% +like 300 + + + align:start position:0% +like 300 +patience and so on okay so here's a + + align:start position:0% +patience and so on okay so here's a + + + align:start position:0% +patience and so on okay so here's a +catalog of the types of data that are + + align:start position:0% +catalog of the types of data that are + + + align:start position:0% +catalog of the types of data that are +available to us so we have a typical + + align:start position:0% +available to us so we have a typical + + + align:start position:0% +available to us so we have a typical +kind of electronic health record data + + align:start position:0% +kind of electronic health record data + + + align:start position:0% +kind of electronic health record data +from hospitals demographics age sex + + align:start position:0% +from hospitals demographics age sex + + + align:start position:0% +from hospitals demographics age sex +socioeconomic status insurance type + + align:start position:0% +socioeconomic status insurance type + + + align:start position:0% +socioeconomic status insurance type +language religion living situation + + align:start position:0% +language religion living situation + + + align:start position:0% +language religion living situation +family structure location work etc we + + align:start position:0% +family structure location work etc we + + + align:start position:0% +family structure location work etc we +have vital signs your weight your height + + align:start position:0% +have vital signs your weight your height + + + align:start position:0% +have vital signs your weight your height +your pulse respiration rate body + + align:start position:0% +your pulse respiration rate body + + + align:start position:0% +your pulse respiration rate body +temperature etc so these are typically + + align:start position:0% +temperature etc so these are typically + + + align:start position:0% +temperature etc so these are typically +the things that if you ever go to a + + align:start position:0% +the things that if you ever go to a + + + align:start position:0% +the things that if you ever go to a +doctor's office or you go into a + + align:start position:0% +doctor's office or you go into a + + + align:start position:0% +doctor's office or you go into a +hospital nurse will take you aside and + + align:start position:0% +hospital nurse will take you aside and + + + align:start position:0% +hospital nurse will take you aside and +weigh you and measure your height and + + align:start position:0% +weigh you and measure your height and + + + align:start position:0% +weigh you and measure your height and +check your blood pressure and take your + + align:start position:0% +check your blood pressure and take your + + + align:start position:0% +check your blood pressure and take your +temperature and stuff like that these + + align:start position:0% +temperature and stuff like that these + + + align:start position:0% +temperature and stuff like that these +are standard vital signs and so we have + + align:start position:0% +are standard vital signs and so we have + + + align:start position:0% +are standard vital signs and so we have +lots of those recorded medications + + align:start position:0% +lots of those recorded medications + + + align:start position:0% +lots of those recorded medications +prescription medications + + align:start position:0% +prescription medications + + + align:start position:0% +prescription medications +over-the-counter drugs illegal drugs if + + align:start position:0% +over-the-counter drugs illegal drugs if + + + align:start position:0% +over-the-counter drugs illegal drugs if +you're willing not to lie to your + + align:start position:0% +you're willing not to lie to your + + + align:start position:0% +you're willing not to lie to your +healthcare provider alcohol again one of + + align:start position:0% +healthcare provider alcohol again one of + + + align:start position:0% +healthcare provider alcohol again one of +my earliest days I was hanging out with + + align:start position:0% +my earliest days I was hanging out with + + + align:start position:0% +my earliest days I was hanging out with +the cardiologist at Tufts Medical Center + + align:start position:0% +the cardiologist at Tufts Medical Center + + + align:start position:0% +the cardiologist at Tufts Medical Center +and we see this elderly lady who looks + + align:start position:0% +and we see this elderly lady who looks + + + align:start position:0% +and we see this elderly lady who looks +kind of terrible and and we're talking + + align:start position:0% +kind of terrible and and we're talking + + + align:start position:0% +kind of terrible and and we're talking +to her well the doctor is talking to her + + align:start position:0% +to her well the doctor is talking to her + + + align:start position:0% +to her well the doctor is talking to her +I'm trying to stay out of the way and + + align:start position:0% +I'm trying to stay out of the way and + + + align:start position:0% +I'm trying to stay out of the way and +and he says so you know do you drink + + align:start position:0% +and he says so you know do you drink + + + align:start position:0% +and he says so you know do you drink +alcohol and she says oh no never touch + + align:start position:0% +alcohol and she says oh no never touch + + + align:start position:0% +alcohol and she says oh no never touch +the stuff + + align:start position:0% +the stuff + + + align:start position:0% +the stuff +and and then we talked some more and we + + align:start position:0% +and and then we talked some more and we + + + align:start position:0% +and and then we talked some more and we +go out of the out of the patients room + + align:start position:0% +go out of the out of the patients room + + + align:start position:0% +go out of the out of the patients room +and and the doctor turns to me out of + + align:start position:0% +and and the doctor turns to me out of + + + align:start position:0% +and and the doctor turns to me out of +earshot of the patient and says oh she's + + align:start position:0% +earshot of the patient and says oh she's + + + align:start position:0% +earshot of the patient and says oh she's +a chronic drunk I said well how do you + + align:start position:0% +a chronic drunk I said well how do you + + + align:start position:0% +a chronic drunk I said well how do you +know and he says well from lab tests + + align:start position:0% +know and he says well from lab tests + + + align:start position:0% +know and he says well from lab tests +from the appearance of her skin from her + + align:start position:0% +from the appearance of her skin from her + + + align:start position:0% +from the appearance of her skin from her +general demeanor from you know various + + align:start position:0% +general demeanor from you know various + + + align:start position:0% +general demeanor from you know various +sort of ineffable factors and so + + align:start position:0% +sort of ineffable factors and so + + + align:start position:0% +sort of ineffable factors and so +patients lie okay they really do because + + align:start position:0% +patients lie okay they really do because + + + align:start position:0% +patients lie okay they really do because +they don't want to tell you things + + align:start position:0% + + + + align:start position:0% + +okay medications by the way is a big + + align:start position:0% +okay medications by the way is a big + + + align:start position:0% +okay medications by the way is a big +deal so there's this whole field called + + align:start position:0% +deal so there's this whole field called + + + align:start position:0% +deal so there's this whole field called +mad wreck medication reconciliation + + align:start position:0% +mad wreck medication reconciliation + + + align:start position:0% +mad wreck medication reconciliation +which is the hospitals or the doctors + + align:start position:0% +which is the hospitals or the doctors + + + align:start position:0% +which is the hospitals or the doctors +offices attempt to figure out what + + align:start position:0% +offices attempt to figure out what + + + align:start position:0% +offices attempt to figure out what +medications you're actually taking so + + align:start position:0% +medications you're actually taking so + + + align:start position:0% +medications you're actually taking so +I'm a member of the MIT health plan and + + align:start position:0% +I'm a member of the MIT health plan and + + + align:start position:0% +I'm a member of the MIT health plan and +if I sign into my health plan account it + + align:start position:0% +if I sign into my health plan account it + + + align:start position:0% +if I sign into my health plan account it +tells me that I'm taking some pills that + + align:start position:0% +tells me that I'm taking some pills that + + + align:start position:0% +tells me that I'm taking some pills that +I got 12 years ago as part of a + + align:start position:0% +I got 12 years ago as part of a + + + align:start position:0% +I got 12 years ago as part of a +laboratory test but we were you know I + + align:start position:0% +laboratory test but we were you know I + + + align:start position:0% +laboratory test but we were you know I +took two pills which were supposed to + + align:start position:0% +took two pills which were supposed to + + + align:start position:0% +took two pills which were supposed to +have some physiological effect and then + + align:start position:0% +have some physiological effect and then + + + align:start position:0% +have some physiological effect and then +they measured that and I've never gotten + + align:start position:0% +they measured that and I've never gotten + + + align:start position:0% +they measured that and I've never gotten +another pill and never taken one since + + align:start position:0% +another pill and never taken one since + + + align:start position:0% +another pill and never taken one since +then nor would it be particularly good + + align:start position:0% +then nor would it be particularly good + + + align:start position:0% +then nor would it be particularly good +for me but it's still on my record and + + align:start position:0% +for me but it's still on my record and + + + align:start position:0% +for me but it's still on my record and +there's no notice of it ever having been + + align:start position:0% +there's no notice of it ever having been + + + align:start position:0% +there's no notice of it ever having been +discontinued and that's a real problem + + align:start position:0% +discontinued and that's a real problem + + + align:start position:0% +discontinued and that's a real problem +because if you're taking care of a + + align:start position:0% +because if you're taking care of a + + + align:start position:0% +because if you're taking care of a +patient you'd like to understand what + + align:start position:0% +patient you'd like to understand what + + + align:start position:0% +patient you'd like to understand what +drugs they're actually taking it's hard + + align:start position:0% +drugs they're actually taking it's hard + + + align:start position:0% +drugs they're actually taking it's hard +to know okay that lab tests so this is + + align:start position:0% +to know okay that lab tests so this is + + + align:start position:0% +to know okay that lab tests so this is +the things that you you imagine that we + + align:start position:0% +the things that you you imagine that we + + + align:start position:0% +the things that you you imagine that we +do a lot of and these are components of + + align:start position:0% +do a lot of and these are components of + + + align:start position:0% +do a lot of and these are components of +the blood and the urine mainly but also + + align:start position:0% +the blood and the urine mainly but also + + + align:start position:0% +the blood and the urine mainly but also +of the stool saliva spinal fluid fluid + + align:start position:0% +of the stool saliva spinal fluid fluid + + + align:start position:0% +of the stool saliva spinal fluid fluid +taken off the belly joint fluid bone + + align:start position:0% +taken off the belly joint fluid bone + + + align:start position:0% +taken off the belly joint fluid bone +marrow stuff coming out of your lungs + + align:start position:0% +marrow stuff coming out of your lungs + + + align:start position:0% +marrow stuff coming out of your lungs +it's all anything right and any place + + align:start position:0% +it's all anything right and any place + + + align:start position:0% +it's all anything right and any place +where you can produce something some + + align:start position:0% +where you can produce something some + + + align:start position:0% +where you can produce something some +specimen they can send it to a lab and + + align:start position:0% +specimen they can send it to a lab and + + + align:start position:0% +specimen they can send it to a lab and +measure things in it and they measure + + align:start position:0% +measure things in it and they measure + + + align:start position:0% +measure things in it and they measure +lots and lots of different kinds of + + align:start position:0% +lots and lots of different kinds of + + + align:start position:0% +lots and lots of different kinds of +things and these are often useful + + align:start position:0% +things and these are often useful + + + align:start position:0% +things and these are often useful +pathology qualitative and quantitative + + align:start position:0% +pathology qualitative and quantitative + + + align:start position:0% +pathology qualitative and quantitative +examination of any body tissue for + + align:start position:0% +examination of any body tissue for + + + align:start position:0% +examination of any body tissue for +example biopsy samples or surgical + + align:start position:0% +example biopsy samples or surgical + + + align:start position:0% +example biopsy samples or surgical +scraps you know if they do an operation + + align:start position:0% +scraps you know if they do an operation + + + align:start position:0% +scraps you know if they do an operation +they cut something out of you + + align:start position:0% +they cut something out of you + + + align:start position:0% +they cut something out of you +that typically winds up on a pathologist + + align:start position:0% +that typically winds up on a pathologist + + + align:start position:0% +that typically winds up on a pathologist +bench who then tries to figure out what + + align:start position:0% +bench who then tries to figure out what + + + align:start position:0% +bench who then tries to figure out what +its characteristics are and that's again + + align:start position:0% +its characteristics are and that's again + + + align:start position:0% +its characteristics are and that's again +useful information okay + + align:start position:0% +useful information okay + + + align:start position:0% +useful information okay +microbiology ever since Pasteur we know + + align:start position:0% +microbiology ever since Pasteur we know + + + align:start position:0% +microbiology ever since Pasteur we know +that organisms cause disease and so we + + align:start position:0% +that organisms cause disease and so we + + + align:start position:0% +that organisms cause disease and so we +are quite interested in knowing what + + align:start position:0% +are quite interested in knowing what + + + align:start position:0% +are quite interested in knowing what +organisms are growing inside your body + + align:start position:0% +organisms are growing inside your body + + + align:start position:0% +organisms are growing inside your body +and and typically testing is not only to + + align:start position:0% +and and typically testing is not only to + + + align:start position:0% +and and typically testing is not only to +identify the organism but also to figure + + align:start position:0% +identify the organism but also to figure + + + align:start position:0% +identify the organism but also to figure +out which antibiotics it's sensitive to + + align:start position:0% +out which antibiotics it's sensitive to + + + align:start position:0% +out which antibiotics it's sensitive to +and insensitive to and so you'll see + + align:start position:0% +and insensitive to and so you'll see + + + align:start position:0% +and insensitive to and so you'll see +things like reports of sensitivity + + align:start position:0% +things like reports of sensitivity + + + align:start position:0% +things like reports of sensitivity +testing at various delusions in other + + align:start position:0% +testing at various delusions in other + + + align:start position:0% +testing at various delusions in other +words they try to give a strong dose of + + align:start position:0% +words they try to give a strong dose of + + + align:start position:0% +words they try to give a strong dose of +an antibiotic or weaker dose a weaker + + align:start position:0% +an antibiotic or weaker dose a weaker + + + align:start position:0% +an antibiotic or weaker dose a weaker +dose a weaker dose a weaker dose to see + + align:start position:0% +dose a weaker dose a weaker dose to see + + + align:start position:0% +dose a weaker dose a weaker dose to see +which is the minimum level of dosing + + align:start position:0% +which is the minimum level of dosing + + + align:start position:0% +which is the minimum level of dosing +that's enough to kill the bacteria + + align:start position:0% +that's enough to kill the bacteria + + + align:start position:0% +that's enough to kill the bacteria +there's a comma missing there but input + + align:start position:0% +there's a comma missing there but input + + + align:start position:0% +there's a comma missing there but input +output of fluids is another important + + align:start position:0% +output of fluids is another important + + + align:start position:0% +output of fluids is another important +thing because people especially in the + + align:start position:0% +thing because people especially in the + + + align:start position:0% +thing because people especially in the +hospital often get either dehydrated or + + align:start position:0% +hospital often get either dehydrated or + + + align:start position:0% +hospital often get either dehydrated or +over hydrated and neither of those is + + align:start position:0% +over hydrated and neither of those is + + + align:start position:0% +over hydrated and neither of those is +good for you and so trying to keep track + + align:start position:0% +good for you and so trying to keep track + + + align:start position:0% +good for you and so trying to keep track +of what's going into you and what's + + align:start position:0% +of what's going into you and what's + + + align:start position:0% +of what's going into you and what's +coming out of you is important then + + align:start position:0% +coming out of you is important then + + + align:start position:0% +coming out of you is important then +there are tons of notes so an important + + align:start position:0% +there are tons of notes so an important + + + align:start position:0% +there are tons of notes so an important +one that we're going to look at in this + + align:start position:0% +one that we're going to look at in this + + + align:start position:0% +one that we're going to look at in this +class is discharge summaries so these + + align:start position:0% +class is discharge summaries so these + + + align:start position:0% +class is discharge summaries so these +are the typically long notes that are + + align:start position:0% +are the typically long notes that are + + + align:start position:0% +are the typically long notes that are +written at the end of a hospitalization + + align:start position:0% +written at the end of a hospitalization + + + align:start position:0% +written at the end of a hospitalization +so this is a summary of why you came in + + align:start position:0% +so this is a summary of why you came in + + + align:start position:0% +so this is a summary of why you came in +what they did to you the main things + + align:start position:0% +what they did to you the main things + + + align:start position:0% +what they did to you the main things +they discovered about you and then plans + + align:start position:0% +they discovered about you and then plans + + + align:start position:0% +they discovered about you and then plans +for what to do after your discharge + + align:start position:0% +for what to do after your discharge + + + align:start position:0% +for what to do after your discharge +where are you going to go what drugs are + + align:start position:0% +where are you going to go what drugs are + + + align:start position:0% +where are you going to go what drugs are +you going to be taking when are you + + align:start position:0% +you going to be taking when are you + + + align:start position:0% +you going to be taking when are you +supposed to come back for follow-up etc + + align:start position:0% +supposed to come back for follow-up etc + + + align:start position:0% +supposed to come back for follow-up etc +I'll show you a excruciating Lee long + + align:start position:0% +I'll show you a excruciating Lee long + + + align:start position:0% +I'll show you a excruciating Lee long +one of those later in the lecture today + + align:start position:0% +one of those later in the lecture today + + + align:start position:0% +one of those later in the lecture today +but we also have notes from attendings + + align:start position:0% +but we also have notes from attendings + + + align:start position:0% +but we also have notes from attendings +under residents nurses various + + align:start position:0% +under residents nurses various + + + align:start position:0% +under residents nurses various +specialties consultants the referring + + align:start position:0% +specialties consultants the referring + + + align:start position:0% +specialties consultants the referring +physician if somebody sends you to the + + align:start position:0% +physician if somebody sends you to the + + + align:start position:0% +physician if somebody sends you to the +hospital that doctor will usually write + + align:start position:0% +hospital that doctor will usually write + + + align:start position:0% +hospital that doctor will usually write +a note saying this is what I'm + + align:start position:0% +a note saying this is what I'm + + + align:start position:0% +a note saying this is what I'm +interested in here's why I'm sending in + + align:start position:0% +interested in here's why I'm sending in + + + align:start position:0% +interested in here's why I'm sending in +the patient there are letters back to + + align:start position:0% +the patient there are letters back to + + + align:start position:0% +the patient there are letters back to +the referring physician saying okay this + + align:start position:0% +the referring physician saying okay this + + + align:start position:0% +the referring physician saying okay this +is what we found out here's the answer + + align:start position:0% +is what we found out here's the answer + + + align:start position:0% +is what we found out here's the answer +to the question you were asking their + + align:start position:0% +to the question you were asking their + + + align:start position:0% +to the question you were asking their +emergency department notes so that's + + align:start position:0% +emergency department notes so that's + + + align:start position:0% +emergency department notes so that's +often the first contact between the + + align:start position:0% +often the first contact between the + + + align:start position:0% +often the first contact between the +patient and the healthcare system so + + align:start position:0% +patient and the healthcare system so + + + align:start position:0% +patient and the healthcare system so +these are all important and then there's + + align:start position:0% +these are all important and then there's + + + align:start position:0% +these are all important and then there's +tons and tons of billing data so + + align:start position:0% +tons and tons of billing data so + + + align:start position:0% +tons and tons of billing data so +remember the EHR systems were initially + + align:start position:0% +remember the EHR systems were initially + + + align:start position:0% +remember the EHR systems were initially +designed by accountants and they were + + align:start position:0% +designed by accountants and they were + + + align:start position:0% +designed by accountants and they were +designed for the purpose of billing and + + align:start position:0% +designed for the purpose of billing and + + + align:start position:0% +designed for the purpose of billing and +so we capture a lot of data about + + align:start position:0% +so we capture a lot of data about + + + align:start position:0% +so we capture a lot of data about +formalized ways of describing the + + align:start position:0% +formalized ways of describing the + + + align:start position:0% +formalized ways of describing the +condition of the patient and what was + + align:start position:0% +condition of the patient and what was + + + align:start position:0% +condition of the patient and what was +done to the patient in order to submit + + align:start position:0% +done to the patient in order to submit + + + align:start position:0% +done to the patient in order to submit +the right bills you obviously want to + + align:start position:0% +the right bills you obviously want to + + + align:start position:0% +the right bills you obviously want to +bill for it as much as possible but you + + align:start position:0% +bill for it as much as possible but you + + + align:start position:0% +bill for it as much as possible but you +have to be able to justify the bills + + align:start position:0% +have to be able to justify the bills + + + align:start position:0% +have to be able to justify the bills +that you submit because insurance + + align:start position:0% +that you submit because insurance + + + align:start position:0% +that you submit because insurance +companies and Medicare and Medicaid + + align:start position:0% +companies and Medicare and Medicaid + + + align:start position:0% +companies and Medicare and Medicaid +don't have a good sense of humor and if + + align:start position:0% +don't have a good sense of humor and if + + + align:start position:0% +don't have a good sense of humor and if +you submit bills for things that you + + align:start position:0% +you submit bills for things that you + + + align:start position:0% +you submit bills for things that you +can't justify then you get penalized + + align:start position:0% +can't justify then you get penalized + + + align:start position:0% +can't justify then you get penalized +okay and then there are administrative + + align:start position:0% +okay and then there are administrative + + + align:start position:0% +okay and then there are administrative +data like which service are you on so + + align:start position:0% +data like which service are you on so + + + align:start position:0% +data like which service are you on so +this this is occasionally a confusing + + align:start position:0% +this this is occasionally a confusing + + + align:start position:0% +this this is occasionally a confusing +thing you can go into the hospital and + + align:start position:0% +thing you can go into the hospital and + + + align:start position:0% +thing you can go into the hospital and +have heart problems but it turns out + + align:start position:0% +have heart problems but it turns out + + + align:start position:0% +have heart problems but it turns out +that the heart intensive care unit the + + align:start position:0% +that the heart intensive care unit the + + + align:start position:0% +that the heart intensive care unit the +cardiac intensive care unit is full up + + align:start position:0% +cardiac intensive care unit is full up + + + align:start position:0% +cardiac intensive care unit is full up +with patients but there's an extra bed + + align:start position:0% +with patients but there's an extra bed + + + align:start position:0% +with patients but there's an extra bed +in the pulmonary intensive care unit and + + align:start position:0% +in the pulmonary intensive care unit and + + + align:start position:0% +in the pulmonary intensive care unit and +so they stick you in that unit but + + align:start position:0% +so they stick you in that unit but + + + align:start position:0% +so they stick you in that unit but +you're still on the cardiology service + + align:start position:0% +you're still on the cardiology service + + + align:start position:0% +you're still on the cardiology service +and so there are these sort of mixture + + align:start position:0% +and so there are these sort of mixture + + + align:start position:0% +and so there are these sort of mixture +kinds of cases that you still have to + + align:start position:0% +kinds of cases that you still have to + + + align:start position:0% +kinds of cases that you still have to +take care of transfers are when you get + + align:start position:0% +take care of transfers are when you get + + + align:start position:0% +take care of transfers are when you get +transferred from one place to another in + + align:start position:0% +transferred from one place to another in + + + align:start position:0% +transferred from one place to another in +the hospital imaging data so I'm not + + align:start position:0% +the hospital imaging data so I'm not + + + align:start position:0% +the hospital imaging data so I'm not +going to talk about that much today but + + align:start position:0% +going to talk about that much today but + + + align:start position:0% +going to talk about that much today but +there are x-rays ultrasound CT MRI PET + + align:start position:0% +there are x-rays ultrasound CT MRI PET + + + align:start position:0% +there are x-rays ultrasound CT MRI PET +scans retinal scans endoscopy + + align:start position:0% +scans retinal scans endoscopy + + + align:start position:0% +scans retinal scans endoscopy +photographs of like your skin and stuff + + align:start position:0% +photographs of like your skin and stuff + + + align:start position:0% +photographs of like your skin and stuff +like that so this is all imaging data + + align:start position:0% +like that so this is all imaging data + + + align:start position:0% +like that so this is all imaging data +and there's been a tremendous amount of + + align:start position:0% +and there's been a tremendous amount of + + + align:start position:0% +and there's been a tremendous amount of +progress recently in applying machine + + align:start position:0% +progress recently in applying machine + + + align:start position:0% +progress recently in applying machine +learning technique + + align:start position:0% +learning technique + + + align:start position:0% +learning technique +to try to interpret the contents of + + align:start position:0% +to try to interpret the contents of + + + align:start position:0% +to try to interpret the contents of +these data so these are also very + + align:start position:0% +these data so these are also very + + + align:start position:0% +these data so these are also very +important and then there's the whole + + align:start position:0% +important and then there's the whole + + + align:start position:0% +important and then there's the whole +quantified self-movement + + align:start position:0% +quantified self-movement + + + align:start position:0% +quantified self-movement +I mean how many of you wear a activity + + align:start position:0% +I mean how many of you wear a activity + + + align:start position:0% +I mean how many of you wear a activity +tracker only about a third I'm surprised + + align:start position:0% +tracker only about a third I'm surprised + + + align:start position:0% +tracker only about a third I'm surprised +that the place like MIT so you know we + + align:start position:0% +that the place like MIT so you know we + + + align:start position:0% +that the place like MIT so you know we +measure steps and elevation change and + + align:start position:0% +measure steps and elevation change and + + + align:start position:0% +measure steps and elevation change and +workouts and you can record vital signs + + align:start position:0% +workouts and you can record vital signs + + + align:start position:0% +workouts and you can record vital signs +and diet and your blood sugar especially + + align:start position:0% +and diet and your blood sugar especially + + + align:start position:0% +and diet and your blood sugar especially +if you're diabetic allergies allergic + + align:start position:0% +if you're diabetic allergies allergic + + + align:start position:0% +if you're diabetic allergies allergic +incidents there's all this mindfulness + + align:start position:0% +incidents there's all this mindfulness + + + align:start position:0% +incidents there's all this mindfulness +mood sleep pain sexual activity and then + + align:start position:0% +mood sleep pain sexual activity and then + + + align:start position:0% +mood sleep pain sexual activity and then +people have developed this idea of n of + + align:start position:0% +people have developed this idea of n of + + + align:start position:0% +people have developed this idea of n of +one experiments where for example I had + + align:start position:0% +one experiments where for example I had + + + align:start position:0% +one experiments where for example I had +a student some years ago who was + + align:start position:0% +a student some years ago who was + + + align:start position:0% +a student some years ago who was +suffered from psoriasis + + align:start position:0% +suffered from psoriasis + + + align:start position:0% +suffered from psoriasis +it's a Brodie condition of the skin and + + align:start position:0% +it's a Brodie condition of the skin and + + + align:start position:0% +it's a Brodie condition of the skin and +the problem is there are no good cures + + align:start position:0% +the problem is there are no good cures + + + align:start position:0% +the problem is there are no good cures +for it and so people who suffer from + + align:start position:0% +for it and so people who suffer from + + + align:start position:0% +for it and so people who suffer from +psoriasis try all kinds of things you + + align:start position:0% +psoriasis try all kinds of things you + + + align:start position:0% +psoriasis try all kinds of things you +know they stop eating nuts for a while + + align:start position:0% +know they stop eating nuts for a while + + + align:start position:0% +know they stop eating nuts for a while +or they douse themselves with vinegar or + + align:start position:0% +or they douse themselves with vinegar or + + + align:start position:0% +or they douse themselves with vinegar or +they do you know whatever crazy thing + + align:start position:0% +they do you know whatever crazy thing + + + align:start position:0% +they do you know whatever crazy thing +comes to mind and we don't have a good + + align:start position:0% +comes to mind and we don't have a good + + + align:start position:0% +comes to mind and we don't have a good +theory for how to treat this disease but + + align:start position:0% +theory for how to treat this disease but + + + align:start position:0% +theory for how to treat this disease but +on the other hand some things work for + + align:start position:0% +on the other hand some things work for + + + align:start position:0% +on the other hand some things work for +some people and so there's a whole + + align:start position:0% +some people and so there's a whole + + + align:start position:0% +some people and so there's a whole +methodology that has been developed that + + align:start position:0% +methodology that has been developed that + + + align:start position:0% +methodology that has been developed that +says when you try these things act like + + align:start position:0% +says when you try these things act like + + + align:start position:0% +says when you try these things act like +a scientist have hypotheses take good + + align:start position:0% +a scientist have hypotheses take good + + + align:start position:0% +a scientist have hypotheses take good +notes collect good data be cognizant of + + align:start position:0% +notes collect good data be cognizant of + + + align:start position:0% +notes collect good data be cognizant of +things like onset periods where you know + + align:start position:0% +things like onset periods where you know + + + align:start position:0% +things like onset periods where you know +you may have to drip vinegar on yourself + + align:start position:0% +you may have to drip vinegar on yourself + + + align:start position:0% +you may have to drip vinegar on yourself +for a week before you see any effect so + + align:start position:0% +for a week before you see any effect so + + + align:start position:0% +for a week before you see any effect so +if it doesn't do anything after one day + + align:start position:0% +if it doesn't do anything after one day + + + align:start position:0% +if it doesn't do anything after one day +don't stop and furthermore if you stop + + align:start position:0% +don't stop and furthermore if you stop + + + align:start position:0% +don't stop and furthermore if you stop +then don't start something new + + align:start position:0% +then don't start something new + + + align:start position:0% +then don't start something new +immediately because you will then be + + align:start position:0% +immediately because you will then be + + + align:start position:0% +immediately because you will then be +confused about whether this is the + + align:start position:0% +confused about whether this is the + + + align:start position:0% +confused about whether this is the +effect of the thing you were on before + + align:start position:0% +effect of the thing you were on before + + + align:start position:0% +effect of the thing you were on before +or the new thing that you're trying so + + align:start position:0% +or the new thing that you're trying so + + + align:start position:0% +or the new thing that you're trying so +there's all sorts of ideas like that + + align:start position:0% +there's all sorts of ideas like that + + + align:start position:0% +there's all sorts of ideas like that +okay so this is a slide from our paper + + align:start position:0% +okay so this is a slide from our paper + + + align:start position:0% +okay so this is a slide from our paper +on on mimic three and it gives you a + + align:start position:0% +on on mimic three and it gives you a + + + align:start position:0% +on on mimic three and it gives you a +kind of overview of what's going on with + + align:start position:0% +kind of overview of what's going on with + + + align:start position:0% +kind of overview of what's going on with +the patient so if you look at this I'm + + align:start position:0% +the patient so if you look at this I'm + + + align:start position:0% +the patient so if you look at this I'm +gonna point with my hands at the top is + + align:start position:0% +gonna point with my hands at the top is + + + align:start position:0% +gonna point with my hands at the top is +something very important this patient + + align:start position:0% +something very important this patient + + + align:start position:0% +something very important this patient +starts off at full code that means that + + align:start position:0% +starts off at full code that means that + + + align:start position:0% +starts off at full code that means that +if something bad happens to him he wants + + align:start position:0% +if something bad happens to him he wants + + + align:start position:0% +if something bad happens to him he wants +everything to be done to try to save him + + align:start position:0% +everything to be done to try to save him + + + align:start position:0% +everything to be done to try to save him +and he winds up in comfort measures only + + align:start position:0% +and he winds up in comfort measures only + + + align:start position:0% +and he winds up in comfort measures only +which means that if something bad + + align:start position:0% +which means that if something bad + + + align:start position:0% +which means that if something bad +happens to him he wants to die where his + + align:start position:0% +happens to him he wants to die where his + + + align:start position:0% +happens to him he wants to die where his +family does if if he's unconscious + + align:start position:0% +family does if if he's unconscious + + + align:start position:0% +family does if if he's unconscious +right so what else do we know about this + + align:start position:0% +right so what else do we know about this + + + align:start position:0% +right so what else do we know about this +guy well GCS is the Glasgow Coma score + + align:start position:0% +guy well GCS is the Glasgow Coma score + + + align:start position:0% +guy well GCS is the Glasgow Coma score +and it's a way of quantifying people's + + align:start position:0% +and it's a way of quantifying people's + + + align:start position:0% +and it's a way of quantifying people's +level of consciousness and you see that + + align:start position:0% +level of consciousness and you see that + + + align:start position:0% +level of consciousness and you see that +at the beginning this patient is + + align:start position:0% +at the beginning this patient is + + + align:start position:0% +at the beginning this patient is +oriented and then gets confused and + + align:start position:0% +oriented and then gets confused and + + + align:start position:0% +oriented and then gets confused and +finally as only making incomprehensible + + align:start position:0% +finally as only making incomprehensible + + + align:start position:0% +finally as only making incomprehensible +words or sounds motor is able to obey + + align:start position:0% +words or sounds motor is able to obey + + + align:start position:0% +words or sounds motor is able to obey +commands eventually he's only able to + + align:start position:0% +commands eventually he's only able to + + + align:start position:0% +commands eventually he's only able to +flex when you stimulate his muscles so + + align:start position:0% +flex when you stimulate his muscles so + + + align:start position:0% +flex when you stimulate his muscles so +he's no longer conscious high movements + + align:start position:0% +he's no longer conscious high movements + + + align:start position:0% +he's no longer conscious high movements +he's able to follow you spontaneously + + align:start position:0% +he's able to follow you spontaneously + + + align:start position:0% +he's able to follow you spontaneously +he's able to orient to speech and + + align:start position:0% +he's able to orient to speech and + + + align:start position:0% +he's able to orient to speech and +eventually no more intuition at all so + + align:start position:0% +eventually no more intuition at all so + + + align:start position:0% +eventually no more intuition at all so +this is clearly somebody who's going + + align:start position:0% +this is clearly somebody who's going + + + align:start position:0% +this is clearly somebody who's going +downhill quickly and in fact dies at the + + align:start position:0% +downhill quickly and in fact dies at the + + + align:start position:0% +downhill quickly and in fact dies at the +end of this of this episode + + align:start position:0% +end of this of this episode + + + align:start position:0% +end of this of this episode +now we then look at labs so we can see + + align:start position:0% +now we then look at labs so we can see + + + align:start position:0% +now we then look at labs so we can see +what is their level of platelets at + + align:start position:0% +what is their level of platelets at + + + align:start position:0% +what is their level of platelets at +about the time that they're measured + + align:start position:0% +about the time that they're measured + + + align:start position:0% +about the time that they're measured +their creatinine level their white blood + + align:start position:0% +their creatinine level their white blood + + + align:start position:0% +their creatinine level their white blood +cell count the neutrophil percentage etc + + align:start position:0% +cell count the neutrophil percentage etc + + + align:start position:0% +cell count the neutrophil percentage etc +and there's not every possible data + + align:start position:0% +and there's not every possible data + + + align:start position:0% +and there's not every possible data +point on the slide this is just + + align:start position:0% +point on the slide this is just + + + align:start position:0% +point on the slide this is just +illustrative the next section is + + align:start position:0% +illustrative the next section is + + + align:start position:0% +illustrative the next section is +medications so the person is on morphine + + align:start position:0% +medications so the person is on morphine + + + align:start position:0% +medications so the person is on morphine +of they're on vancomycin which is an + + align:start position:0% +of they're on vancomycin which is an + + + align:start position:0% +of they're on vancomycin which is an +antibiotic Pipper asila and I don't know + + align:start position:0% +antibiotic Pipper asila and I don't know + + + align:start position:0% +antibiotic Pipper asila and I don't know +that is somebody no that's what okay + + align:start position:0% +that is somebody no that's what okay + + + align:start position:0% +that is somebody no that's what okay +sodium chloride 9% so that's just + + align:start position:0% +sodium chloride 9% so that's just + + + align:start position:0% +sodium chloride 9% so that's just +keeping him hydrated amiodarone and + + align:start position:0% +keeping him hydrated amiodarone and + + + align:start position:0% +keeping him hydrated amiodarone and +dextrose or dextrose is giving him some + + align:start position:0% +dextrose or dextrose is giving him some + + + align:start position:0% +dextrose or dextrose is giving him some +energy and then these are the various + + align:start position:0% +energy and then these are the various + + + align:start position:0% +energy and then these are the various +measurements so you see the heart rate + + align:start position:0% +measurements so you see the heart rate + + + align:start position:0% +measurements so you see the heart rate +for example is up pretty high and is + + align:start position:0% +for example is up pretty high and is + + + align:start position:0% +for example is up pretty high and is +going up near the end the oxygen + + align:start position:0% +going up near the end the oxygen + + + align:start position:0% +going up near the end the oxygen +saturation starts off pretty good but + + align:start position:0% +saturation starts off pretty good but + + + align:start position:0% +saturation starts off pretty good but +here we're down to you know sixty + + align:start position:0% +here we're down to you know sixty + + + align:start position:0% +here we're down to you know sixty +percent or fifty percent o2 sat which is + + align:start position:0% +percent or fifty percent o2 sat which is + + + align:start position:0% +percent or fifty percent o2 sat which is +supposed to be above about 92 in order + + align:start position:0% +supposed to be above about 92 in order + + + align:start position:0% +supposed to be above about 92 in order +to be considered reasonable so again + + align:start position:0% +to be considered reasonable so again + + + align:start position:0% +to be considered reasonable so again +this is a very consistent picture of + + align:start position:0% +this is a very consistent picture of + + + align:start position:0% +this is a very consistent picture of +things going very badly wrong for this + + align:start position:0% +things going very badly wrong for this + + + align:start position:0% +things going very badly wrong for this +particular patient so this is all the + + align:start position:0% +particular patient so this is all the + + + align:start position:0% +particular patient so this is all the +data in the database now if you want to + + align:start position:0% +data in the database now if you want to + + + align:start position:0% +data in the database now if you want to +try to analyze some of this stuff you + + align:start position:0% +try to analyze some of this stuff you + + + align:start position:0% +try to analyze some of this stuff you +can say well let's look at the ages at + + align:start position:0% +can say well let's look at the ages at + + + align:start position:0% +can say well let's look at the ages at +the time of the last lab measurement in + + align:start position:0% +the time of the last lab measurement in + + + align:start position:0% +the time of the last lab measurement in +the database so we have the times of all + + align:start position:0% +the database so we have the times of all + + + align:start position:0% +the database so we have the times of all +the lab measurements so we can see that + + align:start position:0% +the lab measurements so we can see that + + + align:start position:0% +the lab measurements so we can see that +many of the ICU population are fairly + + align:start position:0% +many of the ICU population are fairly + + + align:start position:0% +many of the ICU population are fairly +old right there's a relatively small + + align:start position:0% +old right there's a relatively small + + + align:start position:0% +old right there's a relatively small +number of young people and then a + + align:start position:0% +number of young people and then a + + + align:start position:0% +number of young people and then a +growing number of older people in both + + align:start position:0% +growing number of older people in both + + + align:start position:0% +growing number of older people in both +both females and males if we look at age + + align:start position:0% +both females and males if we look at age + + + align:start position:0% +both females and males if we look at age +8 admission by gender so this is age at + + align:start position:0% +8 admission by gender so this is age at + + + align:start position:0% +8 admission by gender so this is age at +admission not age at the time the last + + align:start position:0% +admission not age at the time the last + + + align:start position:0% +admission not age at the time the last +lab measurement was done it's pretty + + align:start position:0% +lab measurement was done it's pretty + + + align:start position:0% +lab measurement was done it's pretty +similar curve so we see that you know + + align:start position:0% +similar curve so we see that you know + + + align:start position:0% +similar curve so we see that you know +females were sixty four point two one at + + align:start position:0% +females were sixty four point two one at + + + align:start position:0% +females were sixty four point two one at +time of last measurement lab measurement + + align:start position:0% +time of last measurement lab measurement + + + align:start position:0% +time of last measurement lab measurement +sixty three point five at the time of + + align:start position:0% +sixty three point five at the time of + + + align:start position:0% +sixty three point five at the time of +admission so we can look at demographics + + align:start position:0% +admission so we can look at demographics + + + align:start position:0% +admission so we can look at demographics +and demographics typically includes + + align:start position:0% +and demographics typically includes + + + align:start position:0% +and demographics typically includes +these kinds of factors which I mentioned + + align:start position:0% +these kinds of factors which I mentioned + + + align:start position:0% +these kinds of factors which I mentioned +before and again if we're interested in + + align:start position:0% +before and again if we're interested in + + + align:start position:0% +before and again if we're interested in +the relationship between this and for + + align:start position:0% +the relationship between this and for + + + align:start position:0% +the relationship between this and for +example the age distribution we see that + + align:start position:0% +example the age distribution we see that + + + align:start position:0% +example the age distribution we see that +if you look at the + + align:start position:0% +if you look at the + + + align:start position:0% +if you look at the +different admission types so you can be + + align:start position:0% +different admission types so you can be + + + align:start position:0% +different admission types so you can be +either admitted through before an + + align:start position:0% +either admitted through before an + + + align:start position:0% +either admitted through before an +emergency for some urgent care or + + align:start position:0% +emergency for some urgent care or + + + align:start position:0% +emergency for some urgent care or +electively + + align:start position:0% +electively + + + align:start position:0% +electively +and it doesn't seem to make a whole lot + + align:start position:0% +and it doesn't seem to make a whole lot + + + align:start position:0% +and it doesn't seem to make a whole lot +of difference at least in the means of + + align:start position:0% +of difference at least in the means of + + + align:start position:0% +of difference at least in the means of +the population age distribution on the + + align:start position:0% +the population age distribution on the + + + align:start position:0% +the population age distribution on the +other hand if you look at insurance type + + align:start position:0% +other hand if you look at insurance type + + + align:start position:0% +other hand if you look at insurance type +and say what who's paying the bills + + align:start position:0% +and say what who's paying the bills + + + align:start position:0% +and say what who's paying the bills +there's a big difference in the age + + align:start position:0% +there's a big difference in the age + + + align:start position:0% +there's a big difference in the age +distributions now why do you think that + + align:start position:0% +distributions now why do you think that + + + align:start position:0% +distributions now why do you think that +private insurance drops way off at about + + align:start position:0% +private insurance drops way off at about + + + align:start position:0% +private insurance drops way off at about +65 it's because of Medicare so Medicare + + align:start position:0% +65 it's because of Medicare so Medicare + + + align:start position:0% +65 it's because of Medicare so Medicare +covers people over 65 years old there's + + align:start position:0% +covers people over 65 years old there's + + + align:start position:0% +covers people over 65 years old there's +a terrible story I have to tell you I + + align:start position:0% +a terrible story I have to tell you I + + + align:start position:0% +a terrible story I have to tell you I +was talking to somebody at an insurance + + align:start position:0% +was talking to somebody at an insurance + + + align:start position:0% +was talking to somebody at an insurance +company it's a bit cynical and he said + + align:start position:0% +company it's a bit cynical and he said + + + align:start position:0% +company it's a bit cynical and he said +suppose that you see a 63 year old + + align:start position:0% +suppose that you see a 63 year old + + + align:start position:0% +suppose that you see a 63 year old +patient who's developing type 2 diabetes + + align:start position:0% +patient who's developing type 2 diabetes + + + align:start position:0% +patient who's developing type 2 diabetes +what should you do for him well there + + align:start position:0% +what should you do for him well there + + + align:start position:0% +what should you do for him well there +are standard things you should do for + + align:start position:0% +are standard things you should do for + + + align:start position:0% +are standard things you should do for +somebody developing type 2 diabetes like + + align:start position:0% +somebody developing type 2 diabetes like + + + align:start position:0% +somebody developing type 2 diabetes like +get him to eat better again him to lose + + align:start position:0% +get him to eat better again him to lose + + + align:start position:0% +get him to eat better again him to lose +weight get him to exercise more etc etc + + align:start position:0% +weight get him to exercise more etc etc + + + align:start position:0% +weight get him to exercise more etc etc +but his cynical answer was absolutely + + align:start position:0% +but his cynical answer was absolutely + + + align:start position:0% +but his cynical answer was absolutely +nothing okay why well it's very cheap to + + align:start position:0% +nothing okay why well it's very cheap to + + + align:start position:0% +nothing okay why well it's very cheap to +do nothing most people who develop type + + align:start position:0% +do nothing most people who develop type + + + align:start position:0% +do nothing most people who develop type +2 diabetes don't get real sick in the + + align:start position:0% +2 diabetes don't get real sick in the + + + align:start position:0% +2 diabetes don't get real sick in the +next two years and by the time this + + align:start position:0% +next two years and by the time this + + + align:start position:0% +next two years and by the time this +patient is 65 he'll be the government's + + align:start position:0% +patient is 65 he'll be the government's + + + align:start position:0% +patient is 65 he'll be the government's +responsibility not the insurance + + align:start position:0% +responsibility not the insurance + + + align:start position:0% +responsibility not the insurance +companies okay nice + + align:start position:0% + + + + align:start position:0% + +okay so of course a lot of the elderly + + align:start position:0% +okay so of course a lot of the elderly + + + align:start position:0% +okay so of course a lot of the elderly +are insured by Medicare or Medicaid not + + align:start position:0% +are insured by Medicare or Medicaid not + + + align:start position:0% +are insured by Medicare or Medicaid not +that surprising self-pay is a pretty + + align:start position:0% +that surprising self-pay is a pretty + + + align:start position:0% +that surprising self-pay is a pretty +small number because it's insanely + + align:start position:0% +small number because it's insanely + + + align:start position:0% +small number because it's insanely +expensive to pay for your own health + + align:start position:0% +expensive to pay for your own health + + + align:start position:0% +expensive to pay for your own health +care what about where you came from + + align:start position:0% +care what about where you came from + + + align:start position:0% +care what about where you came from +right were you referred from a clinic or + + align:start position:0% +right were you referred from a clinic or + + + align:start position:0% +right were you referred from a clinic or +were you an emergency room admit or were + + align:start position:0% +were you an emergency room admit or were + + + align:start position:0% +were you an emergency room admit or were +you referred from an HMO or etc and + + align:start position:0% +you referred from an HMO or etc and + + + align:start position:0% +you referred from an HMO or etc and +other than transfer from a skilled + + align:start position:0% +other than transfer from a skilled + + + align:start position:0% +other than transfer from a skilled +nursing facility were transferred within + + align:start position:0% +nursing facility were transferred within + + + align:start position:0% +nursing facility were transferred within +the facility within the hospital it + + align:start position:0% +the facility within the hospital it + + + align:start position:0% +the facility within the hospital it +doesn't make much difference the + + align:start position:0% +doesn't make much difference the + + + align:start position:0% +doesn't make much difference the +averages there and the distributions + + align:start position:0% +averages there and the distributions + + + align:start position:0% +averages there and the distributions +look moderately similar if you're coming + + align:start position:0% +look moderately similar if you're coming + + + align:start position:0% +look moderately similar if you're coming +from a skilled nursing facility if you + + align:start position:0% +from a skilled nursing facility if you + + + align:start position:0% +from a skilled nursing facility if you +are in a skilled nursing facility you're + + align:start position:0% +are in a skilled nursing facility you're + + + align:start position:0% +are in a skilled nursing facility you're +probably old because younger people + + align:start position:0% +probably old because younger people + + + align:start position:0% +probably old because younger people +don't typically know need skilled + + align:start position:0% +don't typically know need skilled + + + align:start position:0% +don't typically know need skilled +nursing care and I'm not sure why + + align:start position:0% +nursing care and I'm not sure why + + + align:start position:0% +nursing care and I'm not sure why +transfers within the facility are + + align:start position:0% +transfers within the facility are + + + align:start position:0% +transfers within the facility are +significantly younger ages but it's true + + align:start position:0% +significantly younger ages but it's true + + + align:start position:0% +significantly younger ages but it's true +in from the mimic data what about H of + + align:start position:0% +in from the mimic data what about H of + + + align:start position:0% +in from the mimic data what about H of +add admission by language so some people + + align:start position:0% +add admission by language so some people + + + align:start position:0% +add admission by language so some people +speak English some speak people speak + + align:start position:0% +speak English some speak people speak + + + align:start position:0% +speak English some speak people speak +not available some people speak Spanish + + align:start position:0% +not available some people speak Spanish + + + align:start position:0% +not available some people speak Spanish +it's not a row so it turns out the + + align:start position:0% +it's not a row so it turns out the + + + align:start position:0% +it's not a row so it turns out the +Russians are the oldest right and that + + align:start position:0% +Russians are the oldest right and that + + + align:start position:0% +Russians are the oldest right and that +may have to do with immigration patterns + + align:start position:0% +may have to do with immigration patterns + + + align:start position:0% +may have to do with immigration patterns +or I don't know exactly why but that's + + align:start position:0% +or I don't know exactly why but that's + + + align:start position:0% +or I don't know exactly why but that's +that's the data that's what the data + + align:start position:0% +that's the data that's what the data + + + align:start position:0% +that's the data that's what the data +show if you do it by ethnicity it turns + + align:start position:0% +show if you do it by ethnicity it turns + + + align:start position:0% +show if you do it by ethnicity it turns +out that African Americans on the whole + + align:start position:0% +out that African Americans on the whole + + + align:start position:0% +out that African Americans on the whole +are somewhat younger than whites and + + align:start position:0% +are somewhat younger than whites and + + + align:start position:0% +are somewhat younger than whites and +Hispanics are somewhat younger yet so + + align:start position:0% +Hispanics are somewhat younger yet so + + + align:start position:0% +Hispanics are somewhat younger yet so +that means that those subpopulations + + align:start position:0% +that means that those subpopulations + + + align:start position:0% +that means that those subpopulations +apparently need + + align:start position:0% +apparently need + + + align:start position:0% +apparently need +tensive care earlier in life than than + + align:start position:0% +tensive care earlier in life than than + + + align:start position:0% +tensive care earlier in life than than +whites so this is a topic that's very + + align:start position:0% +whites so this is a topic that's very + + + align:start position:0% +whites so this is a topic that's very +hot right now + + align:start position:0% +hot right now + + + align:start position:0% +hot right now +discussions about how bias might play + + align:start position:0% +discussions about how bias might play + + + align:start position:0% +discussions about how bias might play +into healthcare yeah it just means that + + align:start position:0% +into healthcare yeah it just means that + + + align:start position:0% +into healthcare yeah it just means that +you know somebody refused to say what + + align:start position:0% +you know somebody refused to say what + + + align:start position:0% +you know somebody refused to say what +their ethnicity was yeah I think I'm not + + align:start position:0% +their ethnicity was yeah I think I'm not + + + align:start position:0% +their ethnicity was yeah I think I'm not +positive just this also represents like + + align:start position:0% +positive just this also represents like + + + align:start position:0% +positive just this also represents like +Boston's it's the catchment basin of the + + align:start position:0% +Boston's it's the catchment basin of the + + + align:start position:0% +Boston's it's the catchment basin of the +Beth Israel Deaconess Hospital which is + + align:start position:0% +Beth Israel Deaconess Hospital which is + + + align:start position:0% +Beth Israel Deaconess Hospital which is +Boston clearly but but they're all you + + align:start position:0% +Boston clearly but but they're all you + + + align:start position:0% +Boston clearly but but they're all you +know it turns out that like a lot of + + align:start position:0% +know it turns out that like a lot of + + + align:start position:0% +know it turns out that like a lot of +North Shore people go to Mass General + + align:start position:0% +North Shore people go to Mass General + + + align:start position:0% +North Shore people go to Mass General +and and so different hospitals have + + align:start position:0% +and and so different hospitals have + + + align:start position:0% +and and so different hospitals have +different catchment basins everybody + + align:start position:0% +different catchment basins everybody + + + align:start position:0% +different catchment basins everybody +these are all people who at some point + + align:start position:0% +these are all people who at some point + + + align:start position:0% +these are all people who at some point +were in the ICU so these are the sicker + + align:start position:0% +were in the ICU so these are the sicker + + + align:start position:0% +were in the ICU so these are the sicker +patients yeah so that is a higher + + align:start position:0% + + + + align:start position:0% + +no actually I don't remember if I have + + align:start position:0% +no actually I don't remember if I have + + + align:start position:0% +no actually I don't remember if I have +that graph I think this is cumulative + + align:start position:0% +that graph I think this is cumulative + + + align:start position:0% +that graph I think this is cumulative +okay so so the most most people are are + + align:start position:0% +okay so so the most most people are are + + + align:start position:0% +okay so so the most most people are are +white for whatever the definition of + + align:start position:0% +white for whatever the definition of + + + align:start position:0% +white for whatever the definition of +white we're using and I think it's only + + align:start position:0% +white we're using and I think it's only + + + align:start position:0% +white we're using and I think it's only +the increment that you see on top okay + + align:start position:0% + + + + align:start position:0% + +all right how about marital status well + + align:start position:0% +all right how about marital status well + + + align:start position:0% +all right how about marital status well +according to this it's bad to be single + + align:start position:0% +according to this it's bad to be single + + + align:start position:0% +according to this it's bad to be single +right so I could sort of see that for + + align:start position:0% +right so I could sort of see that for + + + align:start position:0% +right so I could sort of see that for +hospitalization I'm not sure why it's + + align:start position:0% +hospitalization I'm not sure why it's + + + align:start position:0% +hospitalization I'm not sure why it's +true for the ICU because if you don't + + align:start position:0% +true for the ICU because if you don't + + + align:start position:0% +true for the ICU because if you don't +have anybody at home to take care of you + + align:start position:0% +have anybody at home to take care of you + + + align:start position:0% +have anybody at home to take care of you +and you get sick it seems reasonable + + align:start position:0% +and you get sick it seems reasonable + + + align:start position:0% +and you get sick it seems reasonable +that you'd be more likely to wind up in + + align:start position:0% +that you'd be more likely to wind up in + + + align:start position:0% +that you'd be more likely to wind up in +the hospital but I don't know why you'd + + align:start position:0% +the hospital but I don't know why you'd + + + align:start position:0% +the hospital but I don't know why you'd +wind up in intensive care + + align:start position:0% +wind up in intensive care + + + align:start position:0% +wind up in intensive care +yeah probably younger and those are + + align:start position:0% +yeah probably younger and those are + + + align:start position:0% +yeah probably younger and those are +probably younger yes yeah yeah that's + + align:start position:0% +probably younger yes yeah yeah that's + + + align:start position:0% +probably younger yes yeah yeah that's +probably also right yep + + align:start position:0% + + + + align:start position:0% + +okay so here's an interesting question a + + align:start position:0% +okay so here's an interesting question a + + + align:start position:0% +okay so here's an interesting question a +little bit related to something you'll + + align:start position:0% +little bit related to something you'll + + + align:start position:0% +little bit related to something you'll +see on the next problem set so could we + + align:start position:0% +see on the next problem set so could we + + + align:start position:0% +see on the next problem set so could we +predict in hospital mortality from just + + align:start position:0% +predict in hospital mortality from just + + + align:start position:0% +predict in hospital mortality from just +these demographic features so I'm using + + align:start position:0% +these demographic features so I'm using + + + align:start position:0% +these demographic features so I'm using +a tool in in language called R this is a + + align:start position:0% +a tool in in language called R this is a + + + align:start position:0% +a tool in in language called R this is a +general linear model and I've set it up + + align:start position:0% +general linear model and I've set it up + + + align:start position:0% +general linear model and I've set it up +to do basically logistic regression and + + align:start position:0% +to do basically logistic regression and + + + align:start position:0% +to do basically logistic regression and +it says I'm predicting whether you die + + align:start position:0% +it says I'm predicting whether you die + + + align:start position:0% +it says I'm predicting whether you die +in the hospital based on these + + align:start position:0% +in the hospital based on these + + + align:start position:0% +in the hospital based on these +demographic factors and it turns out + + align:start position:0% +demographic factors and it turns out + + + align:start position:0% +demographic factors and it turns out +that the only ones that are highly + + align:start position:0% +that the only ones that are highly + + + align:start position:0% +that the only ones that are highly +significant are age so that's not + + align:start position:0% +significant are age so that's not + + + align:start position:0% +significant are age so that's not +surprising that older people are more + + align:start position:0% +surprising that older people are more + + + align:start position:0% +surprising that older people are more +likely to die than younger people it's + + align:start position:0% +likely to die than younger people it's + + + align:start position:0% +likely to die than younger people it's +generally true and if I'm unable to + + align:start position:0% +generally true and if I'm unable to + + + align:start position:0% +generally true and if I'm unable to +obtain your ethnicity or I don't know + + align:start position:0% +obtain your ethnicity or I don't know + + + align:start position:0% +obtain your ethnicity or I don't know +your ethnicity then you're more likely + + align:start position:0% +your ethnicity then you're more likely + + + align:start position:0% +your ethnicity then you're more likely +to die I've no clue why that might be + + align:start position:0% +to die I've no clue why that might be + + + align:start position:0% +to die I've no clue why that might be +the case and other things are not as + + align:start position:0% +the case and other things are not as + + + align:start position:0% +the case and other things are not as +significant so if you speak Spanish or + + align:start position:0% +significant so if you speak Spanish or + + + align:start position:0% +significant so if you speak Spanish or +English you're slightly less likely to + + align:start position:0% +English you're slightly less likely to + + + align:start position:0% +English you're slightly less likely to +die you see a negative contribution here + + align:start position:0% +die you see a negative contribution here + + + align:start position:0% +die you see a negative contribution here +and if your if you speak Russian you're + + align:start position:0% +and if your if you speak Russian you're + + + align:start position:0% +and if your if you speak Russian you're +slightly less likely to die but it's + + align:start position:0% +slightly less likely to die but it's + + + align:start position:0% +slightly less likely to die but it's +significant not at the P equal point oh + + align:start position:0% +significant not at the P equal point oh + + + align:start position:0% +significant not at the P equal point oh +five level but it is at the P equal + + align:start position:0% +five level but it is at the P equal + + + align:start position:0% +five level but it is at the P equal +point oh six level and marriage doesn't + + align:start position:0% +point oh six level and marriage doesn't + + + align:start position:0% +point oh six level and marriage doesn't +seem to make much difference in + + align:start position:0% +seem to make much difference in + + + align:start position:0% +seem to make much difference in +predicting whether you're gonna die or + + align:start position:0% +predicting whether you're gonna die or + + + align:start position:0% +predicting whether you're gonna die or +not + + align:start position:0% +not + + + align:start position:0% +not +now remember this is ICU patients and + + align:start position:0% +now remember this is ICU patients and + + + align:start position:0% +now remember this is ICU patients and +we're looking at in hospital mortality + + align:start position:0% +we're looking at in hospital mortality + + + align:start position:0% +we're looking at in hospital mortality +yeah I don't know because it could be + + align:start position:0% +yeah I don't know because it could be + + + align:start position:0% +yeah I don't know because it could be +that unable to obtain means that they + + align:start position:0% +that unable to obtain means that they + + + align:start position:0% +that unable to obtain means that they +died before we could ask them no cuz + + align:start position:0% +died before we could ask them no cuz + + + align:start position:0% +died before we could ask them no cuz +though there wouldn't be that many of + + align:start position:0% +though there wouldn't be that many of + + + align:start position:0% +though there wouldn't be that many of +those people I think there are not that + + align:start position:0% +those people I think there are not that + + + align:start position:0% +those people I think there are not that +many people who don't live past the + + align:start position:0% +many people who don't live past the + + + align:start position:0% +many people who don't live past the +intake interview and they do ask them + + align:start position:0% + + + + align:start position:0% + +yeah that would that would be an example + + align:start position:0% +yeah that would that would be an example + + + align:start position:0% +yeah that would that would be an example +but I don't think you'd see enough such + + align:start position:0% +but I don't think you'd see enough such + + + align:start position:0% +but I don't think you'd see enough such +people to show up statistically okay + + align:start position:0% +people to show up statistically okay + + + align:start position:0% +people to show up statistically okay +well so I've already mentioned that + + align:start position:0% +well so I've already mentioned that + + + align:start position:0% +well so I've already mentioned that +there's this problem of having moved + + align:start position:0% +there's this problem of having moved + + + align:start position:0% +there's this problem of having moved +from care view to meta vision just in + + align:start position:0% +from care view to meta vision just in + + + align:start position:0% +from care view to meta vision just in +the mimic database but of course this is + + align:start position:0% +the mimic database but of course this is + + + align:start position:0% +the mimic database but of course this is +a much bigger problem around the country + + align:start position:0% +a much bigger problem around the country + + + align:start position:0% +a much bigger problem around the country +and around the world because every + + align:start position:0% +and around the world because every + + + align:start position:0% +and around the world because every +hospital has its own way of keeping + + align:start position:0% +hospital has its own way of keeping + + + align:start position:0% +hospital has its own way of keeping +records and wouldn't it be nice if we + + align:start position:0% +records and wouldn't it be nice if we + + + align:start position:0% +records and wouldn't it be nice if we +had standards and of course there's this + + align:start position:0% +had standards and of course there's this + + + align:start position:0% +had standards and of course there's this +funny phrase the wonderful thing about + + align:start position:0% +funny phrase the wonderful thing about + + + align:start position:0% +funny phrase the wonderful thing about +standards is that there's so many to + + align:start position:0% +standards is that there's so many to + + + align:start position:0% +standards is that there's so many to +choose from so for example if you look + + align:start position:0% +choose from so for example if you look + + + align:start position:0% +choose from so for example if you look +at prescriptions in the mimic database + + align:start position:0% +at prescriptions in the mimic database + + + align:start position:0% +at prescriptions in the mimic database +here are two particular prescriptions + + align:start position:0% +here are two particular prescriptions + + + align:start position:0% +here are two particular prescriptions +for subject number 57 139 admitted on + + align:start position:0% +for subject number 57 139 admitted on + + + align:start position:0% +for subject number 57 139 admitted on +admission ID 155 for 7 oh and so they're + + align:start position:0% +admission ID 155 for 7 oh and so they're + + + align:start position:0% +admission ID 155 for 7 oh and so they're +they have the same start date but + + align:start position:0% +they have the same start date but + + + align:start position:0% +they have the same start date but +different end dates one is a + + align:start position:0% +different end dates one is a + + + align:start position:0% +different end dates one is a +prescription for tylenol acetaminophen + + align:start position:0% +prescription for tylenol acetaminophen + + + align:start position:0% +prescription for tylenol acetaminophen +and the other is for through beta salt + + align:start position:0% +and the other is for through beta salt + + + align:start position:0% +and the other is for through beta salt +propionate 0.05% cream that's a skin + + align:start position:0% +propionate 0.05% cream that's a skin + + + align:start position:0% +propionate 0.05% cream that's a skin +lotion thing for I think it's a steroid + + align:start position:0% +lotion thing for I think it's a steroid + + + align:start position:0% +lotion thing for I think it's a steroid +skin skin cream so if you look in the B + + align:start position:0% +skin skin cream so if you look in the B + + + align:start position:0% +skin skin cream so if you look in the B +eyes database they have their own + + align:start position:0% +eyes database they have their own + + + align:start position:0% +eyes database they have their own +private formulary code where this thing + + align:start position:0% +private formulary code where this thing + + + align:start position:0% +private formulary code where this thing +is a set 325 and this thing is Club dot + + align:start position:0% +is a set 325 and this thing is Club dot + + + align:start position:0% +is a set 325 and this thing is Club dot +zero five C 30 right and if you look + + align:start position:0% +zero five C 30 right and if you look + + + align:start position:0% +zero five C 30 right and if you look +there's also something called a GSN + + align:start position:0% +there's also something called a GSN + + + align:start position:0% +there's also something called a GSN +which is some commercial coding system + + align:start position:0% +which is some commercial coding system + + + align:start position:0% +which is some commercial coding system +for drugs maybe having to do with who + + align:start position:0% +for drugs maybe having to do with who + + + align:start position:0% +for drugs maybe having to do with who +their drug supplier is at the hospital + + align:start position:0% +their drug supplier is at the hospital + + + align:start position:0% +their drug supplier is at the hospital +and these have different codes + + align:start position:0% +and these have different codes + + + align:start position:0% +and these have different codes +there's the national drug code which is + + align:start position:0% +there's the national drug code which is + + + align:start position:0% +there's the national drug code which is +an FDA + + align:start position:0% +an FDA + + + align:start position:0% +an FDA +assigned nine digit code that specifies + + align:start position:0% +assigned nine digit code that specifies + + + align:start position:0% +assigned nine digit code that specifies +who made the drug what form it's in and + + align:start position:0% +who made the drug what form it's in and + + + align:start position:0% +who made the drug what form it's in and +what's its strength and so you get these + + align:start position:0% +what's its strength and so you get these + + + align:start position:0% +what's its strength and so you get these +then there's a human readable + + align:start position:0% +then there's a human readable + + + align:start position:0% +then there's a human readable +description that says tylenol comes in + + align:start position:0% +description that says tylenol comes in + + + align:start position:0% +description that says tylenol comes in +three hundred twenty five milligram + + align:start position:0% +three hundred twenty five milligram + + + align:start position:0% +three hundred twenty five milligram +tablets and this club a dose all comes + + align:start position:0% +tablets and this club a dose all comes + + + align:start position:0% +tablets and this club a dose all comes +in 30 gram tubes and the dose is + + align:start position:0% +in 30 gram tubes and the dose is + + + align:start position:0% +in 30 gram tubes and the dose is +supposed to be three twenty five to six + + align:start position:0% +supposed to be three twenty five to six + + + align:start position:0% +supposed to be three twenty five to six +fifty ie one to two tablets measured in + + align:start position:0% +fifty ie one to two tablets measured in + + + align:start position:0% +fifty ie one to two tablets measured in +milligrams the dose here is one + + align:start position:0% +milligrams the dose here is one + + + align:start position:0% +milligrams the dose here is one +application whatever that is I don't + + align:start position:0% +application whatever that is I don't + + + align:start position:0% +application whatever that is I don't +know what the point of one means and + + align:start position:0% +know what the point of one means and + + + align:start position:0% +know what the point of one means and +this is a tablet and that's a tube and + + align:start position:0% +this is a tablet and that's a tube and + + + align:start position:0% +this is a tablet and that's a tube and +this is taken orally and that's + + align:start position:0% +this is taken orally and that's + + + align:start position:0% +this is taken orally and that's +administered on the skin right so this + + align:start position:0% +administered on the skin right so this + + + align:start position:0% +administered on the skin right so this +is a local database for doctor the + + align:start position:0% +is a local database for doctor the + + + align:start position:0% +is a local database for doctor the +package + + align:start position:0% + + + + align:start position:0% + +at most hospitals that's true now it + + align:start position:0% +at most hospitals that's true now it + + + align:start position:0% +at most hospitals that's true now it +wasn't true when the mimic database + + align:start position:0% +wasn't true when the mimic database + + + align:start position:0% +wasn't true when the mimic database +started being collected and the BI was + + align:start position:0% +started being collected and the BI was + + + align:start position:0% +started being collected and the BI was +relatively late in moving to that + + align:start position:0% +relatively late in moving to that + + + align:start position:0% +relatively late in moving to that +compared to some of the other hospitals + + align:start position:0% +compared to some of the other hospitals + + + align:start position:0% +compared to some of the other hospitals +in the Boston area I mean each hospital + + align:start position:0% +in the Boston area I mean each hospital + + + align:start position:0% +in the Boston area I mean each hospital +has its own digital or what it thinks is + + align:start position:0% +has its own digital or what it thinks is + + + align:start position:0% +has its own digital or what it thinks is +most important and and I think the B I + + align:start position:0% +most important and and I think the B I + + + align:start position:0% +most important and and I think the B I +just didn't prioritize it as much as + + align:start position:0% +just didn't prioritize it as much as + + + align:start position:0% +just didn't prioritize it as much as +some of the other hospitals okay so then + + align:start position:0% +some of the other hospitals okay so then + + + align:start position:0% +some of the other hospitals okay so then +I said well if you look at prescriptions + + align:start position:0% +I said well if you look at prescriptions + + + align:start position:0% +I said well if you look at prescriptions +how often are they given so remember we + + align:start position:0% +how often are they given so remember we + + + align:start position:0% +how often are they given so remember we +have about 60,000 ICU stays and so I so + + align:start position:0% +have about 60,000 ICU stays and so I so + + + align:start position:0% +have about 60,000 ICU stays and so I so +osmotic dextrose was given eighty seven + + align:start position:0% +osmotic dextrose was given eighty seven + + + align:start position:0% +osmotic dextrose was given eighty seven +thousand times to various people sodium + + align:start position:0% +thousand times to various people sodium + + + align:start position:0% +thousand times to various people sodium +chloride point nine percent flush do you + + align:start position:0% +chloride point nine percent flush do you + + + align:start position:0% +chloride point nine percent flush do you +know what that is + + align:start position:0% +know what that is + + + align:start position:0% +know what that is +have you ever had an IV so periodically + + align:start position:0% +have you ever had an IV so periodically + + + align:start position:0% +have you ever had an IV so periodically +the nurse comes by and squirts a little + + align:start position:0% +the nurse comes by and squirts a little + + + align:start position:0% +the nurse comes by and squirts a little +bit of stuff in in the IV to make sure + + align:start position:0% +bit of stuff in in the IV to make sure + + + align:start position:0% +bit of stuff in in the IV to make sure +that it hasn't clogged up that's what + + align:start position:0% +that it hasn't clogged up that's what + + + align:start position:0% +that it hasn't clogged up that's what +that is + + align:start position:0% +that is + + + align:start position:0% +that is +insulin SW I don't know salt water + + align:start position:0% +insulin SW I don't know salt water + + + align:start position:0% +insulin SW I don't know salt water +I don't know what s W is magnesium + + align:start position:0% +I don't know what s W is magnesium + + + align:start position:0% +I don't know what s W is magnesium +sulfate dextrose v in water + + align:start position:0% +sulfate dextrose v in water + + + align:start position:0% +sulfate dextrose v in water +furosemide is a diuretic potassium + + align:start position:0% +furosemide is a diuretic potassium + + + align:start position:0% +furosemide is a diuretic potassium +chloride replenishes potassium that + + align:start position:0% +chloride replenishes potassium that + + + align:start position:0% +chloride replenishes potassium that +people are often low on and then you go + + align:start position:0% +people are often low on and then you go + + + align:start position:0% +people are often low on and then you go +so why is there this d5w and that d5w + + align:start position:0% +so why is there this d5w and that d5w + + + align:start position:0% +so why is there this d5w and that d5w +and that's probably some data or in the + + align:start position:0% +and that's probably some data or in the + + + align:start position:0% +and that's probably some data or in the +system okay they one of them has an NDC + + align:start position:0% +system okay they one of them has an NDC + + + align:start position:0% +system okay they one of them has an NDC +code associated with it and the other + + align:start position:0% +code associated with it and the other + + + align:start position:0% +code associated with it and the other +one doesn't but probably should yeah the + + align:start position:0% +one doesn't but probably should yeah the + + + align:start position:0% +one doesn't but probably should yeah the +NDC code should be standard across the + + align:start position:0% +NDC code should be standard across the + + + align:start position:0% +NDC code should be standard across the +country because those are FDA assigned + + align:start position:0% +country because those are FDA assigned + + + align:start position:0% +country because those are FDA assigned +codes but not every hospital uses them + + align:start position:0% +codes but not every hospital uses them + + + align:start position:0% +codes but not every hospital uses them +okay and for the ones that say zero I'm + + align:start position:0% +okay and for the ones that say zero I'm + + + align:start position:0% +okay and for the ones that say zero I'm +not sure why they're not associated with + + align:start position:0% +not sure why they're not associated with + + + align:start position:0% +not sure why they're not associated with +the code in this this hospitals database + + align:start position:0% +the code in this this hospitals database + + + align:start position:0% +the code in this this hospitals database +okay next most common you see normal + + align:start position:0% +okay next most common you see normal + + + align:start position:0% +okay next most common you see normal +saline 0.9% sodium chloride so that was + + align:start position:0% +saline 0.9% sodium chloride so that was + + + align:start position:0% +saline 0.9% sodium chloride so that was +the same stuff as the flush solution but + + align:start position:0% +the same stuff as the flush solution but + + + align:start position:0% +the same stuff as the flush solution but +this time not being used for flush + + align:start position:0% +this time not being used for flush + + + align:start position:0% +this time not being used for flush +metoprolol is a beta blocker + + align:start position:0% +metoprolol is a beta blocker + + + align:start position:0% +metoprolol is a beta blocker +here's another insulin this time with an + + align:start position:0% +here's another insulin this time with an + + + align:start position:0% +here's another insulin this time with an +NDC code etc I love bag and vial okay so + + align:start position:0% +NDC code etc I love bag and vial okay so + + + align:start position:0% +NDC code etc I love bag and vial okay so +these are not exactly medications a bag + + align:start position:0% +these are not exactly medications a bag + + + align:start position:0% +these are not exactly medications a bag +is literally like a baggie that they put + + align:start position:0% +is literally like a baggie that they put + + + align:start position:0% +is literally like a baggie that they put +something into and a vial is literally + + align:start position:0% +something into and a vial is literally + + + align:start position:0% +something into and a vial is literally +something that they put pills in and why + + align:start position:0% +something that they put pills in and why + + + align:start position:0% +something that they put pills in and why +is that in the database because they get + + align:start position:0% +is that in the database because they get + + + align:start position:0% +is that in the database because they get +to charge for it okay and I don't know + + align:start position:0% +to charge for it okay and I don't know + + + align:start position:0% +to charge for it okay and I don't know +what the charges but it wouldn't + + align:start position:0% +what the charges but it wouldn't + + + align:start position:0% +what the charges but it wouldn't +surprise me if you're paying five bucks + + align:start position:0% +surprise me if you're paying five bucks + + + align:start position:0% +surprise me if you're paying five bucks +for a plastic bag to put something in + + align:start position:0% +for a plastic bag to put something in + + + align:start position:0% +for a plastic bag to put something in +okay so if we say well how many pharmacy + + align:start position:0% +okay so if we say well how many pharmacy + + + align:start position:0% +okay so if we say well how many pharmacy +orders are there for admission at this + + align:start position:0% +orders are there for admission at this + + + align:start position:0% +orders are there for admission at this +hospital and the answer is a lot so if + + align:start position:0% +hospital and the answer is a lot so if + + + align:start position:0% +hospital and the answer is a lot so if +you look at it's a very long tailed + + align:start position:0% +you look at it's a very long tailed + + + align:start position:0% +you look at it's a very long tailed +distribution goes out to about 2,500 but + + align:start position:0% +distribution goes out to about 2,500 but + + + align:start position:0% +distribution goes out to about 2,500 but +you see if I blow up just the numbers up + + align:start position:0% +you see if I blow up just the numbers up + + + align:start position:0% +you see if I blow up just the numbers up +to about two hundred there's a very + + align:start position:0% +to about two hundred there's a very + + + align:start position:0% +to about two hundred there's a very +large number of people with like two + + align:start position:0% + + + + align:start position:0% + +prescriptions filled and then a fairly + + align:start position:0% +prescriptions filled and then a fairly + + + align:start position:0% +prescriptions filled and then a fairly +declining number with with more and then + + align:start position:0% +declining number with with more and then + + + align:start position:0% +declining number with with more and then +it's a very long tail so can you imagine + + align:start position:0% +it's a very long tail so can you imagine + + + align:start position:0% +it's a very long tail so can you imagine +you know twenty five hundred things + + align:start position:0% +you know twenty five hundred things + + + align:start position:0% +you know twenty five hundred things +prescribed for you during a hospital + + align:start position:0% +prescribed for you during a hospital + + + align:start position:0% +prescribed for you during a hospital +stay + + align:start position:0% + + + + align:start position:0% + +well a little more about standards so + + align:start position:0% +well a little more about standards so + + + align:start position:0% +well a little more about standards so +NDC is probably the best of the coding + + align:start position:0% +NDC is probably the best of the coding + + + align:start position:0% +NDC is probably the best of the coding +systems and it's developed by the FDA + + align:start position:0% +systems and it's developed by the FDA + + + align:start position:0% +systems and it's developed by the FDA +the picture up on the top right shows + + align:start position:0% +the picture up on the top right shows + + + align:start position:0% +the picture up on the top right shows +that the first four digits are the + + align:start position:0% +that the first four digits are the + + + align:start position:0% +that the first four digits are the +so-called label er that's usually the + + align:start position:0% +so-called label er that's usually the + + + align:start position:0% +so-called label er that's usually the +person who produced the drugs or at + + align:start position:0% +person who produced the drugs or at + + + align:start position:0% +person who produced the drugs or at +least the person who distributes them + + align:start position:0% +least the person who distributes them + + + align:start position:0% +least the person who distributes them +the second four digit number is the form + + align:start position:0% +the second four digit number is the form + + + align:start position:0% +the second four digit number is the form +of the drug so whether it's capsules or + + align:start position:0% +of the drug so whether it's capsules or + + + align:start position:0% +of the drug so whether it's capsules or +tablets or liquid or whatever and the + + align:start position:0% +tablets or liquid or whatever and the + + + align:start position:0% +tablets or liquid or whatever and the +dose and then the the last two digits + + align:start position:0% +dose and then the the last two digits + + + align:start position:0% +dose and then the the last two digits +are a package code which translates into + + align:start position:0% +are a package code which translates into + + + align:start position:0% +are a package code which translates into +the total number of doses that are in a + + align:start position:0% +the total number of doses that are in a + + + align:start position:0% +the total number of doses that are in a +package right so this is a godsend and + + align:start position:0% +package right so this is a godsend and + + + align:start position:0% +package right so this is a godsend and +all of the robotic pharmacies and so on + + align:start position:0% +all of the robotic pharmacies and so on + + + align:start position:0% +all of the robotic pharmacies and so on +rely on using this kind of information + + align:start position:0% +rely on using this kind of information + + + align:start position:0% +rely on using this kind of information +nowadays unfortunately they ran out of + + align:start position:0% +nowadays unfortunately they ran out of + + + align:start position:0% +nowadays unfortunately they ran out of +four-digit numbers and so there's now a + + align:start position:0% +four-digit numbers and so there's now a + + + align:start position:0% +four-digit numbers and so there's now a +they added an extra digit but they + + align:start position:0% +they added an extra digit but they + + + align:start position:0% +they added an extra digit but they +didn't do it systematically and so + + align:start position:0% +didn't do it systematically and so + + + align:start position:0% +didn't do it systematically and so +sometimes they added an extra digit to + + align:start position:0% +sometimes they added an extra digit to + + + align:start position:0% +sometimes they added an extra digit to +the label or and sometimes to the + + align:start position:0% +the label or and sometimes to the + + + align:start position:0% +the label or and sometimes to the +product code and so there's a nightmare + + align:start position:0% +product code and so there's a nightmare + + + align:start position:0% +product code and so there's a nightmare +of translations between the old codes + + align:start position:0% +of translations between the old codes + + + align:start position:0% +of translations between the old codes +and the new codes and you have to have a + + align:start position:0% +and the new codes and you have to have a + + + align:start position:0% +and the new codes and you have to have a +code dictionary in order to do it + + align:start position:0% +code dictionary in order to do it + + + align:start position:0% +code dictionary in order to do it +properly and so on okay well if that + + align:start position:0% +properly and so on okay well if that + + + align:start position:0% +properly and so on okay well if that +weren't good enough the International + + align:start position:0% +weren't good enough the International + + + align:start position:0% +weren't good enough the International +Council for the harmonization of + + align:start position:0% +Council for the harmonization of + + + align:start position:0% +Council for the harmonization of +technical requirements for + + align:start position:0% +technical requirements for + + + align:start position:0% +technical requirements for +pharmaceuticals for human use developed + + align:start position:0% +pharmaceuticals for human use developed + + + align:start position:0% +pharmaceuticals for human use developed +another coding system called meddra + + align:start position:0% +another coding system called meddra + + + align:start position:0% +another coding system called meddra +which is also used in various places and + + align:start position:0% +which is also used in various places and + + + align:start position:0% +which is also used in various places and +this is an international standard which + + align:start position:0% +this is an international standard which + + + align:start position:0% +this is an international standard which +is of course incompatible with the NDC + + align:start position:0% +is of course incompatible with the NDC + + + align:start position:0% +is of course incompatible with the NDC +there are also CPT is the common + + align:start position:0% +there are also CPT is the common + + + align:start position:0% +there are also CPT is the common +procedural terminology which we'll talk + + align:start position:0% +procedural terminology which we'll talk + + + align:start position:0% +procedural terminology which we'll talk +about in a little bit and they have a + + align:start position:0% +about in a little bit and they have a + + + align:start position:0% +about in a little bit and they have a +sub range of their codes which also + + align:start position:0% +sub range of their codes which also + + + align:start position:0% +sub range of their codes which also +correspond to medication administration + + align:start position:0% +correspond to medication administration + + + align:start position:0% +correspond to medication administration +and so this is yet another way of + + align:start position:0% +and so this is yet another way of + + + align:start position:0% +and so this is yet another way of +coding giving medicines and then the + + align:start position:0% +coding giving medicines and then the + + + align:start position:0% +coding giving medicines and then the +HCPCS is yet another set of codes for + + align:start position:0% +HCPCS is yet another set of codes for + + + align:start position:0% +HCPCS is yet another set of codes for +specifying what medicines you've given + + align:start position:0% +specifying what medicines you've given + + + align:start position:0% +specifying what medicines you've given +to somebody and then I had mentioned + + align:start position:0% +to somebody and then I had mentioned + + + align:start position:0% +to somebody and then I had mentioned +this GSN number which apparently the + + align:start position:0% +this GSN number which apparently the + + + align:start position:0% +this GSN number which apparently the +Beth Israel uses this is a commercial + + align:start position:0% +Beth Israel uses this is a commercial + + + align:start position:0% +Beth Israel uses this is a commercial +coding system from a company called + + align:start position:0% +coding system from a company called + + + align:start position:0% +coding system from a company called +First Data Bank that is in the business + + align:start position:0% +First Data Bank that is in the business + + + align:start position:0% +First Data Bank that is in the business +of trying to produce standards but in + + align:start position:0% +of trying to produce standards but in + + + align:start position:0% +of trying to produce standards but in +this case they're producing ones that + + align:start position:0% +this case they're producing ones that + + + align:start position:0% +this case they're producing ones that +are pretty redundant with other existing + + align:start position:0% +are pretty redundant with other existing + + + align:start position:0% +are pretty redundant with other existing +standards but nevertheless for + + align:start position:0% +standards but nevertheless for + + + align:start position:0% +standards but nevertheless for +historical reasons or for whatever + + align:start position:0% +historical reasons or for whatever + + + align:start position:0% +historical reasons or for whatever +reasons people are using these okay + + align:start position:0% +reasons people are using these okay + + + align:start position:0% +reasons people are using these okay +enough of drugs so what procedures were + + align:start position:0% +enough of drugs so what procedures were + + + align:start position:0% +enough of drugs so what procedures were +done to a patient if you look in mimic + + align:start position:0% +done to a patient if you look in mimic + + + align:start position:0% +done to a patient if you look in mimic +there are three tables there's + + align:start position:0% +there are three tables there's + + + align:start position:0% +there are three tables there's +procedures ICD which has icd-9 codes for + + align:start position:0% +procedures ICD which has icd-9 codes for + + + align:start position:0% +procedures ICD which has icd-9 codes for +about a quarter million procedures + + align:start position:0% +about a quarter million procedures + + + align:start position:0% +about a quarter million procedures +there's CPT events which has about half + + align:start position:0% +there's CPT events which has about half + + + align:start position:0% +there's CPT events which has about half +a million six hundred thousand events + + align:start position:0% +a million six hundred thousand events + + + align:start position:0% +a million six hundred thousand events +that are coded in the CPT terminology + + align:start position:0% +that are coded in the CPT terminology + + + align:start position:0% +that are coded in the CPT terminology +and then meta vision the newer of the + + align:start position:0% +and then meta vision the newer of the + + + align:start position:0% +and then meta vision the newer of the +two systems has about a quarter million + + align:start position:0% +two systems has about a quarter million + + + align:start position:0% +two systems has about a quarter million +procedure events that are coded in that + + align:start position:0% +procedure events that are coded in that + + + align:start position:0% +procedure events that are coded in that +system so some examples here's the most + + align:start position:0% +system so some examples here's the most + + + align:start position:0% +system so some examples here's the most +common icd-9 procedure codes so icd-9 + + align:start position:0% +common icd-9 procedure codes so icd-9 + + + align:start position:0% +common icd-9 procedure codes so icd-9 +code 38 93 of which there are 14,000 + + align:start position:0% +code 38 93 of which there are 14,000 + + + align:start position:0% +code 38 93 of which there are 14,000 +instances is venous catheterization not + + align:start position:0% +instances is venous catheterization not + + + align:start position:0% +instances is venous catheterization not +elsewhere classified + + align:start position:0% +elsewhere classified + + + align:start position:0% +elsewhere classified +so what's venous catheterization it's + + align:start position:0% +so what's venous catheterization it's + + + align:start position:0% +so what's venous catheterization it's +when somebody sticks on IV in your vein + + align:start position:0% +when somebody sticks on IV in your vein + + + align:start position:0% +when somebody sticks on IV in your vein +okay very common you show up at a + + align:start position:0% +okay very common you show up at a + + + align:start position:0% +okay very common you show up at a +hospital before they ask you your name + + align:start position:0% +hospital before they ask you your name + + + align:start position:0% +hospital before they ask you your name +they stick an IV in here + + align:start position:0% + + + + align:start position:0% + +that's a buildable event - insertion of + + align:start position:0% +that's a buildable event - insertion of + + + align:start position:0% +that's a buildable event - insertion of +an endotracheal tube you know if you're + + align:start position:0% +an endotracheal tube you know if you're + + + align:start position:0% +an endotracheal tube you know if you're +having any problems like that they stick + + align:start position:0% +having any problems like that they stick + + + align:start position:0% +having any problems like that they stick +it out stick something down your throat + + align:start position:0% +it out stick something down your throat + + + align:start position:0% +it out stick something down your throat +ntral infusion of concentrated + + align:start position:0% +ntral infusion of concentrated + + + align:start position:0% +ntral infusion of concentrated +nutritional substances so if you're not + + align:start position:0% +nutritional substances so if you're not + + + align:start position:0% +nutritional substances so if you're not +able to eat then they feed you through a + + align:start position:0% +able to eat then they feed you through a + + + align:start position:0% +able to eat then they feed you through a +stomach tube okay so that's what that is + + align:start position:0% +stomach tube okay so that's what that is + + + align:start position:0% +stomach tube okay so that's what that is +continuous invasive mechanical + + align:start position:0% +continuous invasive mechanical + + + align:start position:0% +continuous invasive mechanical +ventilation for less than 96 consecutive + + align:start position:0% +ventilation for less than 96 consecutive + + + align:start position:0% +ventilation for less than 96 consecutive +hours so this is being put on a on a + + align:start position:0% +hours so this is being put on a on a + + + align:start position:0% +hours so this is being put on a on a +ventilator that's breathing for you + + align:start position:0% +ventilator that's breathing for you + + + align:start position:0% +ventilator that's breathing for you +etc so you see that there's a very long + + align:start position:0% +etc so you see that there's a very long + + + align:start position:0% +etc so you see that there's a very long +tail of these so those are the icd-9 + + align:start position:0% +tail of these so those are the icd-9 + + + align:start position:0% +tail of these so those are the icd-9 +codes now CPT has its own procedure + + align:start position:0% +codes now CPT has its own procedure + + + align:start position:0% +codes now CPT has its own procedure +codes that go into tremendous amount of + + align:start position:0% +codes that go into tremendous amount of + + + align:start position:0% +codes that go into tremendous amount of +detail so for example this is the + + align:start position:0% +detail so for example this is the + + + align:start position:0% +detail so for example this is the +medicine subsection and it shows you the + + align:start position:0% +medicine subsection and it shows you the + + + align:start position:0% +medicine subsection and it shows you the +kinds of drugs that you're being + + align:start position:0% +kinds of drugs that you're being + + + align:start position:0% +kinds of drugs that you're being +administered that are involved in + + align:start position:0% +administered that are involved in + + + align:start position:0% +administered that are involved in +dialysis or psychiatry or vaccines or + + align:start position:0% +dialysis or psychiatry or vaccines or + + + align:start position:0% +dialysis or psychiatry or vaccines or +whatever and then here are the surgical + + align:start position:0% +whatever and then here are the surgical + + + align:start position:0% +whatever and then here are the surgical +and the radiological codes and there's + + align:start position:0% +and the radiological codes and there's + + + align:start position:0% +and the radiological codes and there's +tons and tons of detail on these yeah no + + align:start position:0% +tons and tons of detail on these yeah no + + + align:start position:0% +tons and tons of detail on these yeah no +these are categories so if if you drill + + align:start position:0% +these are categories so if if you drill + + + align:start position:0% +these are categories so if if you drill +down there's a there's a fan out of that + + align:start position:0% +down there's a there's a fan out of that + + + align:start position:0% +down there's a there's a fan out of that +tree and you get down to individual + + align:start position:0% +tree and you get down to individual + + + align:start position:0% +tree and you get down to individual +codes just as as a nasty surprise CPT is + + align:start position:0% +codes just as as a nasty surprise CPT is + + + align:start position:0% +codes just as as a nasty surprise CPT is +owned by the American College of + + align:start position:0% +owned by the American College of + + + align:start position:0% +owned by the American College of +Physicians and if they they could sue me + + align:start position:0% +Physicians and if they they could sue me + + + align:start position:0% +Physicians and if they they could sue me +if I showed you the actual codes because + + align:start position:0% +if I showed you the actual codes because + + + align:start position:0% +if I showed you the actual codes because +they're copyrighted and you have to pay + + align:start position:0% +they're copyrighted and you have to pay + + + align:start position:0% +they're copyrighted and you have to pay +them if you if you use those codes it's + + align:start position:0% +them if you if you use those codes it's + + + align:start position:0% +them if you if you use those codes it's +crazy + + align:start position:0% +crazy + + + align:start position:0% +crazy +okay so if you look at the number of all + + align:start position:0% +okay so if you look at the number of all + + + align:start position:0% +okay so if you look at the number of all +of these codes per admission you see a + + align:start position:0% +of these codes per admission you see a + + + align:start position:0% +of these codes per admission you see a +distribution like this or if I separate + + align:start position:0% +distribution like this or if I separate + + + align:start position:0% +distribution like this or if I separate +them out you see that there are more + + align:start position:0% +them out you see that there are more + + + align:start position:0% +them out you see that there are more +icd-9 codes and fewer of the cpt and the + + align:start position:0% +icd-9 codes and fewer of the cpt and the + + + align:start position:0% +icd-9 codes and fewer of the cpt and the +codes that are in meta vision but they + + align:start position:0% +codes that are in meta vision but they + + + align:start position:0% +codes that are in meta vision but they +look somewhat similar in their + + align:start position:0% +look somewhat similar in their + + + align:start position:0% +look somewhat similar in their +distributions okay + + align:start position:0% +distributions okay + + + align:start position:0% +distributions okay +lab measurements so you send off a + + align:start position:0% +lab measurements so you send off a + + + align:start position:0% +lab measurements so you send off a +sputum sample blood urine a piece of + + align:start position:0% +sputum sample blood urine a piece of + + + align:start position:0% +sputum sample blood urine a piece of +your brain something they stick it in + + align:start position:0% +your brain something they stick it in + + + align:start position:0% +your brain something they stick it in +some goo and measure something about it + + align:start position:0% +some goo and measure something about it + + + align:start position:0% +some goo and measure something about it +so what is it that they're measuring + + align:start position:0% +so what is it that they're measuring + + + align:start position:0% +so what is it that they're measuring +well it turns out that hematocrit is the + + align:start position:0% +well it turns out that hematocrit is the + + + align:start position:0% +well it turns out that hematocrit is the +most common measurement so this is how + + align:start position:0% +most common measurement so this is how + + + align:start position:0% +most common measurement so this is how +much hemoglobin is in your blood or what + + align:start position:0% +much hemoglobin is in your blood or what + + + align:start position:0% +much hemoglobin is in your blood or what +fraction in your blood and is very + + align:start position:0% +fraction in your blood and is very + + + align:start position:0% +fraction in your blood and is very +important for sick people and the second + + align:start position:0% +important for sick people and the second + + + align:start position:0% +important for sick people and the second +most important is potassium than sodium + + align:start position:0% +most important is potassium than sodium + + + align:start position:0% +most important is potassium than sodium +creatinine chloride urea nitrogen + + align:start position:0% +creatinine chloride urea nitrogen + + + align:start position:0% +creatinine chloride urea nitrogen +bicarbonate etc so this is a long long + + align:start position:0% +bicarbonate etc so this is a long long + + + align:start position:0% +bicarbonate etc so this is a long long +list of different things that can be + + align:start position:0% +list of different things that can be + + + align:start position:0% +list of different things that can be +measured and all the stuff is in the + + align:start position:0% +measured and all the stuff is in the + + + align:start position:0% +measured and all the stuff is in the +database so for example here is patient + + align:start position:0% +database so for example here is patient + + + align:start position:0% +database so for example here is patient +number two in the database and in on + + align:start position:0% +number two in the database and in on + + + align:start position:0% +number two in the database and in on +July 17th of 21:38 this is part of the D + + align:start position:0% +July 17th of 21:38 this is part of the D + + + align:start position:0% +July 17th of 21:38 this is part of the D +identification process to make it + + align:start position:0% +identification process to make it + + + align:start position:0% +identification process to make it +difficult to figure out who the patient + + align:start position:0% +difficult to figure out who the patient + + + align:start position:0% +difficult to figure out who the patient +actually is this person got a test for + + align:start position:0% +actually is this person got a test for + + + align:start position:0% +actually is this person got a test for +their blood and they reported atypical + + align:start position:0% +their blood and they reported atypical + + + align:start position:0% +their blood and they reported atypical +lymphocytes so there are a couple of + + align:start position:0% +lymphocytes so there are a couple of + + + align:start position:0% +lymphocytes so there are a couple of +interesting things to note here one is + + align:start position:0% +interesting things to note here one is + + + align:start position:0% +interesting things to note here one is +that some things have a value and others + + align:start position:0% +that some things have a value and others + + + align:start position:0% +that some things have a value and others +don't so this is a qualitative measure + + align:start position:0% +don't so this is a qualitative measure + + + align:start position:0% +don't so this is a qualitative measure +so there's no value associated with it + + align:start position:0% +so there's no value associated with it + + + align:start position:0% +so there's no value associated with it +just the fact of the label tells you + + align:start position:0% +just the fact of the label tells you + + + align:start position:0% +just the fact of the label tells you +what the result of the test was the + + align:start position:0% +what the result of the test was the + + + align:start position:0% +what the result of the test was the +other thing that's interesting is this + + align:start position:0% +other thing that's interesting is this + + + align:start position:0% +other thing that's interesting is this +last column which is linked and I'll say + + align:start position:0% +last column which is linked and I'll say + + + align:start position:0% +last column which is linked and I'll say +a word about that in a minute + + align:start position:0% +a word about that in a minute + + + align:start position:0% +a word about that in a minute +actually right now so link is the + + align:start position:0% +actually right now so link is the + + + align:start position:0% +actually right now so link is the +logical observation identifier name + + align:start position:0% +logical observation identifier name + + + align:start position:0% +logical observation identifier name +and codes it was developed by our + + align:start position:0% +and codes it was developed by our + + + align:start position:0% +and codes it was developed by our +colleagues at Reagan Street clinic in + + align:start position:0% +colleagues at Reagan Street clinic in + + + align:start position:0% +colleagues at Reagan Street clinic in +Indiana about 15 years ago maybe 20 + + align:start position:0% +Indiana about 15 years ago maybe 20 + + + align:start position:0% +Indiana about 15 years ago maybe 20 +years ago at this point and the attempt + + align:start position:0% +years ago at this point and the attempt + + + align:start position:0% +years ago at this point and the attempt +was to say every different type of + + align:start position:0% +was to say every different type of + + + align:start position:0% +was to say every different type of +laboratory test ought to have a unique + + align:start position:0% +laboratory test ought to have a unique + + + align:start position:0% +laboratory test ought to have a unique +name and they ought to be hierarchical + + align:start position:0% +name and they ought to be hierarchical + + + align:start position:0% +name and they ought to be hierarchical +so that if you have for example three + + align:start position:0% +so that if you have for example three + + + align:start position:0% +so that if you have for example three +different ways of measuring serum + + align:start position:0% +different ways of measuring serum + + + align:start position:0% +different ways of measuring serum +potassium that they're related to each + + align:start position:0% +potassium that they're related to each + + + align:start position:0% +potassium that they're related to each +other but that they're distinct from + + align:start position:0% +other but that they're distinct from + + + align:start position:0% +other but that they're distinct from +each other because there may be + + align:start position:0% +each other because there may be + + + align:start position:0% +each other because there may be +circumstances under which the errors + + align:start position:0% +circumstances under which the errors + + + align:start position:0% +circumstances under which the errors +that you get from one measurement versus + + align:start position:0% +that you get from one measurement versus + + + align:start position:0% +that you get from one measurement versus +another are different and so this is the + + align:start position:0% +another are different and so this is the + + + align:start position:0% +another are different and so this is the +standard way if you send off your blood + + align:start position:0% +standard way if you send off your blood + + + align:start position:0% +standard way if you send off your blood +sample to a lab they send back a string + + align:start position:0% +sample to a lab they send back a string + + + align:start position:0% +sample to a lab they send back a string +like this to the hospital or to your + + align:start position:0% +like this to the hospital or to your + + + align:start position:0% +like this to the hospital or to your +doctor's office that says it's coded in + + align:start position:0% +doctor's office that says it's coded in + + + align:start position:0% +doctor's office that says it's coded in +this OBX coding system and here is the + + align:start position:0% +this OBX coding system and here is the + + + align:start position:0% +this OBX coding system and here is the +link code and this is the sno-med + + align:start position:0% +link code and this is the sno-med + + + align:start position:0% +link code and this is the sno-med +interpretation and so this string is the + + align:start position:0% +interpretation and so this string is the + + + align:start position:0% +interpretation and so this string is the +way that your hospitals EHR or your + + align:start position:0% +way that your hospitals EHR or your + + + align:start position:0% +way that your hospitals EHR or your +doctor's office system figures out what + + align:start position:0% +doctor's office system figures out what + + + align:start position:0% +doctor's office system figures out what +the result of the test was hl7 is this + + align:start position:0% +the result of the test was hl7 is this + + + align:start position:0% +the result of the test was hl7 is this +30 something year old organization that + + align:start position:0% +30 something year old organization that + + + align:start position:0% +30 something year old organization that +has been working on standardizing stuff + + align:start position:0% +has been working on standardizing stuff + + + align:start position:0% +has been working on standardizing stuff +like this and linked as part of their of + + align:start position:0% +like this and linked as part of their of + + + align:start position:0% +like this and linked as part of their of +their standardization so if you look at + + align:start position:0% +their standardization so if you look at + + + align:start position:0% +their standardization so if you look at +these you say well again how many tests + + align:start position:0% +these you say well again how many tests + + + align:start position:0% +these you say well again how many tests +per admission again a huge longtail up + + align:start position:0% +per admission again a huge longtail up + + + align:start position:0% +per admission again a huge longtail up +to about 15,000 for a very small number + + align:start position:0% +to about 15,000 for a very small number + + + align:start position:0% +to about 15,000 for a very small number +of patients if you look at lab tests per + + align:start position:0% +of patients if you look at lab tests per + + + align:start position:0% +of patients if you look at lab tests per +admission you can do a log transform and + + align:start position:0% +admission you can do a log transform and + + + align:start position:0% +admission you can do a log transform and +get something that looks like a more + + align:start position:0% +get something that looks like a more + + + align:start position:0% +get something that looks like a more +reasonable distribution by the way + + align:start position:0% +reasonable distribution by the way + + + align:start position:0% +reasonable distribution by the way +that's a very generic lesson when we're + + align:start position:0% +that's a very generic lesson when we're + + + align:start position:0% +that's a very generic lesson when we're +going to do analyses of these data is + + align:start position:0% +going to do analyses of these data is + + + align:start position:0% +going to do analyses of these data is +that often doing a transform of some + + align:start position:0% +that often doing a transform of some + + + align:start position:0% +that often doing a transform of some +sort like in this case a log takes some + + align:start position:0% +sort like in this case a log takes some + + + align:start position:0% +sort like in this case a log takes some +funny-looking distribution and turns it + + align:start position:0% +funny-looking distribution and turns it + + + align:start position:0% +funny-looking distribution and turns it +into something that looks plausibly + + align:start position:0% +into something that looks plausibly + + + align:start position:0% +into something that looks plausibly +normal which is better for a lot of the + + align:start position:0% +normal which is better for a lot of the + + + align:start position:0% +normal which is better for a lot of the +tech + + align:start position:0% +tech + + + align:start position:0% +tech +yeah those dudes means the same thing + + align:start position:0% +yeah those dudes means the same thing + + + align:start position:0% +yeah those dudes means the same thing +yes I met the great at once - and yes + + align:start position:0% +yes I met the great at once - and yes + + + align:start position:0% +yes I met the great at once - and yes +yes yes that's the whole idea of + + align:start position:0% +yes yes that's the whole idea of + + + align:start position:0% +yes yes that's the whole idea of +creating the standard and that has been + + align:start position:0% +creating the standard and that has been + + + align:start position:0% +creating the standard and that has been +pretty successful pretty successfully + + align:start position:0% +pretty successful pretty successfully + + + align:start position:0% +pretty successful pretty successfully +adopted ok chart events so these are the + + align:start position:0% +adopted ok chart events so these are the + + + align:start position:0% +adopted ok chart events so these are the +things that nurses typically enter at + + align:start position:0% +things that nurses typically enter at + + + align:start position:0% +things that nurses typically enter at +the bedside and so there are 5.1 5.2 + + align:start position:0% +the bedside and so there are 5.1 5.2 + + + align:start position:0% +the bedside and so there are 5.1 5.2 +million heart rates measured in the + + align:start position:0% +million heart rates measured in the + + + align:start position:0% +million heart rates measured in the +mimic database and a Cal previs League + + align:start position:0% +mimic database and a Cal previs League + + + align:start position:0% +mimic database and a Cal previs League +is is an artifact it exists in every + + align:start position:0% +is is an artifact it exists in every + + + align:start position:0% +is is an artifact it exists in every +record and it's some calibration + + align:start position:0% +record and it's some calibration + + + align:start position:0% +record and it's some calibration +something or other that doesn't mean + + align:start position:0% +something or other that doesn't mean + + + align:start position:0% +something or other that doesn't mean +anything I've never been able to figure + + align:start position:0% +anything I've never been able to figure + + + align:start position:0% +anything I've never been able to figure +out exactly what it is + + align:start position:0% +out exactly what it is + + + align:start position:0% +out exactly what it is +spo2 is is the partial pressure of + + align:start position:0% +spo2 is is the partial pressure of + + + align:start position:0% +spo2 is is the partial pressure of +oxygen in your blood if use a pulse + + align:start position:0% +oxygen in your blood if use a pulse + + + align:start position:0% +oxygen in your blood if use a pulse +oximeter that's what that's measuring + + align:start position:0% +oximeter that's what that's measuring + + + align:start position:0% +oximeter that's what that's measuring +respiratory rate heart rhythm active + + align:start position:0% +respiratory rate heart rhythm active + + + align:start position:0% +respiratory rate heart rhythm active +p-type dot dot dot now you might be + + align:start position:0% +p-type dot dot dot now you might be + + + align:start position:0% +p-type dot dot dot now you might be +troubled by the fact that here's heart + + align:start position:0% +troubled by the fact that here's heart + + + align:start position:0% +troubled by the fact that here's heart +rate again right but I've already shown + + align:start position:0% +rate again right but I've already shown + + + align:start position:0% +rate again right but I've already shown +you this that heart rate in care view + + align:start position:0% +you this that heart rate in care view + + + align:start position:0% +you this that heart rate in care view +and heart rate and meta vision were + + align:start position:0% +and heart rate and meta vision were + + + align:start position:0% +and heart rate and meta vision were +coded under different codes in the joint + + align:start position:0% +coded under different codes in the joint + + + align:start position:0% +coded under different codes in the joint +system that we created out of those two + + align:start position:0% +system that we created out of those two + + + align:start position:0% +system that we created out of those two +databases and so you have to take care + + align:start position:0% +databases and so you have to take care + + + align:start position:0% +databases and so you have to take care +of figuring out what's what if you're + + align:start position:0% +of figuring out what's what if you're + + + align:start position:0% +of figuring out what's what if you're +trying to analyze this data not only do + + align:start position:0% +trying to analyze this data not only do + + + align:start position:0% +trying to analyze this data not only do +we have that problem of different age + + align:start position:0% +we have that problem of different age + + + align:start position:0% +we have that problem of different age +distributions across the two different + + align:start position:0% +distributions across the two different + + + align:start position:0% +distributions across the two different +data sets but we also just have the + + align:start position:0% +data sets but we also just have the + + + align:start position:0% +data sets but we also just have the +mechanical problem that there will be + + align:start position:0% +mechanical problem that there will be + + + align:start position:0% +mechanical problem that there will be +things with the same label that may or + + align:start position:0% +things with the same label that may or + + + align:start position:0% +things with the same label that may or +may not represent the same measurement + + align:start position:0% +may not represent the same measurement + + + align:start position:0% +may not represent the same measurement +at different times in the system okay + + align:start position:0% + + + + align:start position:0% + +this is the number of chart entries per + + align:start position:0% +this is the number of chart entries per + + + align:start position:0% +this is the number of chart entries per +admission again on a log scale so you + + align:start position:0% +admission again on a log scale so you + + + align:start position:0% +admission again on a log scale so you +see that there are about 10 to the 3.5 + + align:start position:0% +see that there are about 10 to the 3.5 + + + align:start position:0% +see that there are about 10 to the 3.5 +chart entries per admission so you know + + align:start position:0% +chart entries per admission so you know + + + align:start position:0% +chart entries per admission so you know +thousands of of Admissions of chart + + align:start position:0% +thousands of of Admissions of chart + + + align:start position:0% +thousands of of Admissions of chart +events for admission we also track + + align:start position:0% +events for admission we also track + + + align:start position:0% +events for admission we also track +outputs so Foley catheter allows your + + align:start position:0% +outputs so Foley catheter allows your + + + align:start position:0% +outputs so Foley catheter allows your +your bladder to drain without your + + align:start position:0% +your bladder to drain without your + + + align:start position:0% +your bladder to drain without your +having consciously to go to the bathroom + + align:start position:0% +having consciously to go to the bathroom + + + align:start position:0% +having consciously to go to the bathroom +so they collect that information there + + align:start position:0% +so they collect that information there + + + align:start position:0% +so they collect that information there +are 1.9 million + + align:start position:0% +are 1.9 million + + + align:start position:0% +are 1.9 million +recordings of how much fluid came out of + + align:start position:0% +recordings of how much fluid came out of + + + align:start position:0% +recordings of how much fluid came out of +your bladder chest tubes will drain + + align:start position:0% +your bladder chest tubes will drain + + + align:start position:0% +your bladder chest tubes will drain +stuff out of your chest if you have + + align:start position:0% +stuff out of your chest if you have + + + align:start position:0% +stuff out of your chest if you have +congestion urine is if you pee regularly + + align:start position:0% +congestion urine is if you pee regularly + + + align:start position:0% +congestion urine is if you pee regularly +stool out etc and again I'm not sure I + + align:start position:0% +stool out etc and again I'm not sure I + + + align:start position:0% +stool out etc and again I'm not sure I +understand what the difference is + + align:start position:0% +understand what the difference is + + + align:start position:0% +understand what the difference is +between urine out Foley versus fully + + align:start position:0% +between urine out Foley versus fully + + + align:start position:0% +between urine out Foley versus fully +explained thing but one from care view + + align:start position:0% +explained thing but one from care view + + + align:start position:0% +explained thing but one from care view +and one from meta vision so again + + align:start position:0% +and one from meta vision so again + + + align:start position:0% +and one from meta vision so again +typical kinds of problems if you look at + + align:start position:0% +typical kinds of problems if you look at + + + align:start position:0% +typical kinds of problems if you look at +the number of output events per + + align:start position:0% +the number of output events per + + + align:start position:0% +the number of output events per +admission you're seeing on the order of + + align:start position:0% +admission you're seeing on the order of + + + align:start position:0% +admission you're seeing on the order of +a hundred roughly + + align:start position:0% + + + + align:start position:0% + +well if you're tracking outputs you + + align:start position:0% +well if you're tracking outputs you + + + align:start position:0% +well if you're tracking outputs you +should also track inputs and so they do + + align:start position:0% +should also track inputs and so they do + + + align:start position:0% +should also track inputs and so they do +and so d5w is this dextrose in water + + align:start position:0% +and so d5w is this dextrose in water + + + align:start position:0% +and so d5w is this dextrose in water +0.9% normal saline propofol is an + + align:start position:0% +0.9% normal saline propofol is an + + + align:start position:0% +0.9% normal saline propofol is an +anesthetic insulin heparin blood thinner + + align:start position:0% +anesthetic insulin heparin blood thinner + + + align:start position:0% +anesthetic insulin heparin blood thinner +etc fentanyl's of I think an opioid if I + + align:start position:0% +etc fentanyl's of I think an opioid if I + + + align:start position:0% +etc fentanyl's of I think an opioid if I +remember right + + align:start position:0% +remember right + + + align:start position:0% +remember right +so these are various things that are + + align:start position:0% +so these are various things that are + + + align:start position:0% +so these are various things that are +given to people and they affect the + + align:start position:0% +given to people and they affect the + + + align:start position:0% +given to people and they affect the +volume of the person so this is an + + align:start position:0% +volume of the person so this is an + + + align:start position:0% +volume of the person so this is an +attempt to keep the person in balance + + align:start position:0% +attempt to keep the person in balance + + + align:start position:0% +attempt to keep the person in balance +and keep track of that meta vision + + align:start position:0% +and keep track of that meta vision + + + align:start position:0% +and keep track of that meta vision +inputs are classified somewhat + + align:start position:0% +inputs are classified somewhat + + + align:start position:0% +inputs are classified somewhat +differently but they have similar kinds + + align:start position:0% +differently but they have similar kinds + + + align:start position:0% +differently but they have similar kinds +of data and if you combine them you get + + align:start position:0% +of data and if you combine them you get + + + align:start position:0% +of data and if you combine them you get +again a distribution on a log scale that + + align:start position:0% +again a distribution on a log scale that + + + align:start position:0% +again a distribution on a log scale that +shows that there are on the order of 10 + + align:start position:0% +shows that there are on the order of 10 + + + align:start position:0% +shows that there are on the order of 10 +to the fifth input events so quite a few + + align:start position:0% +to the fifth input events so quite a few + + + align:start position:0% +to the fifth input events so quite a few +input events because this is recorded + + align:start position:0% +input events because this is recorded + + + align:start position:0% +input events because this is recorded +periodically now the paper that I yeah + + align:start position:0% + + + + align:start position:0% + +no no it's it's an input into you so + + align:start position:0% +no no it's it's an input into you so + + + align:start position:0% +no no it's it's an input into you so +it's like you drink a glass of water the + + align:start position:0% +it's like you drink a glass of water the + + + align:start position:0% +it's like you drink a glass of water the +nurse is supposed to record it although + + align:start position:0% +nurse is supposed to record it although + + + align:start position:0% +nurse is supposed to record it although +she doesn't always because she may not + + align:start position:0% +she doesn't always because she may not + + + align:start position:0% +she doesn't always because she may not +notice it but if they hang an IV bag and + + align:start position:0% +notice it but if they hang an IV bag and + + + align:start position:0% +notice it but if they hang an IV bag and +pour a liter of liquid into you they do + + align:start position:0% +pour a liter of liquid into you they do + + + align:start position:0% +pour a liter of liquid into you they do +record that okay all right so I I had + + align:start position:0% +record that okay all right so I I had + + + align:start position:0% +record that okay all right so I I had +you read this interesting paper and a + + align:start position:0% + + + + align:start position:0% + +discussion prior to that paper because + + align:start position:0% +discussion prior to that paper because + + + align:start position:0% +discussion prior to that paper because +one of the authors as a former student + + align:start position:0% +one of the authors as a former student + + + align:start position:0% +one of the authors as a former student +of mine and I know the one of the other + + align:start position:0% +of mine and I know the one of the other + + + align:start position:0% +of mine and I know the one of the other +guys pretty well and the former students + + align:start position:0% +guys pretty well and the former students + + + align:start position:0% +guys pretty well and the former students +at Kohana came back some years ago from + + align:start position:0% +at Kohana came back some years ago from + + + align:start position:0% +at Kohana came back some years ago from +a conference in California and was + + align:start position:0% +a conference in California and was + + + align:start position:0% +a conference in California and was +explaining to me that he ran into a + + align:start position:0% +explaining to me that he ran into a + + + align:start position:0% +explaining to me that he ran into a +venture capitalist who discovered that + + align:start position:0% +venture capitalist who discovered that + + + align:start position:0% +venture capitalist who discovered that +there's an interesting physiological + + align:start position:0% +there's an interesting physiological + + + align:start position:0% +there's an interesting physiological +variation in the epiderm allottee of lab + + align:start position:0% +variation in the epiderm allottee of lab + + + align:start position:0% +variation in the epiderm allottee of lab +tests that are done at night and he + + align:start position:0% +tests that are done at night and he + + + align:start position:0% +tests that are done at night and he +suspected that there's a diurnal + + align:start position:0% +suspected that there's a diurnal + + + align:start position:0% +suspected that there's a diurnal +variation that lab tests actually become + + align:start position:0% +variation that lab tests actually become + + + align:start position:0% +variation that lab tests actually become +more abnormal at night than they do + + align:start position:0% +more abnormal at night than they do + + + align:start position:0% +more abnormal at night than they do +during the day + + align:start position:0% +during the day + + + align:start position:0% +during the day +and Zach who is not only a computer + + align:start position:0% +and Zach who is not only a computer + + + align:start position:0% +and Zach who is not only a computer +science PhD but also a practicing doctor + + align:start position:0% +science PhD but also a practicing doctor + + + align:start position:0% +science PhD but also a practicing doctor +turns to him Francis you're an idiot + + align:start position:0% +turns to him Francis you're an idiot + + + align:start position:0% +turns to him Francis you're an idiot +right who has their blood drawn at 3 + + align:start position:0% +right who has their blood drawn at 3 + + + align:start position:0% +right who has their blood drawn at 3 +o'clock in the morning it's typically + + align:start position:0% +o'clock in the morning it's typically + + + align:start position:0% +o'clock in the morning it's typically +not healthy people right so this is + + align:start position:0% +not healthy people right so this is + + + align:start position:0% +not healthy people right so this is +another of these nice confounding + + align:start position:0% +another of these nice confounding + + + align:start position:0% +another of these nice confounding +stories where if you have a test done in + + align:start position:0% +stories where if you have a test done in + + + align:start position:0% +stories where if you have a test done in +the middle of the night it probably + + align:start position:0% +the middle of the night it probably + + + align:start position:0% +the middle of the night it probably +indicates that you're sicker so he and + + align:start position:0% +indicates that you're sicker so he and + + + align:start position:0% +indicates that you're sicker so he and +Griffin recruited their third author and + + align:start position:0% +Griffin recruited their third author and + + + align:start position:0% +Griffin recruited their third author and +went off and did a very large-scale + + align:start position:0% +went off and did a very large-scale + + + align:start position:0% +went off and did a very large-scale +study of this question which is what the + + align:start position:0% +study of this question which is what the + + + align:start position:0% +study of this question which is what the +paper that I asked you to read reports + + align:start position:0% +paper that I asked you to read reports + + + align:start position:0% +paper that I asked you to read reports +on and so I said well I wonder if I + + align:start position:0% +on and so I said well I wonder if I + + + align:start position:0% +on and so I said well I wonder if I +could reproduce that study in the mimic + + align:start position:0% +could reproduce that study in the mimic + + + align:start position:0% +could reproduce that study in the mimic +database + + align:start position:0% +database + + + align:start position:0% +database +and the answer just in case you get your + + align:start position:0% +and the answer just in case you get your + + + align:start position:0% +and the answer just in case you get your +hopes up was no in large part because we + + align:start position:0% +hopes up was no in large part because we + + + align:start position:0% +hopes up was no in large part because we +just don't have the right kind of data + + align:start position:0% +just don't have the right kind of data + + + align:start position:0% +just don't have the right kind of data +so they're not not that many white blood + + align:start position:0% +so they're not not that many white blood + + + align:start position:0% +so they're not not that many white blood +counts that were measured in the mimic + + align:start position:0% +counts that were measured in the mimic + + + align:start position:0% +counts that were measured in the mimic +database for example but if you look at + + align:start position:0% +database for example but if you look at + + + align:start position:0% +database for example but if you look at +the this is mimic data and if you say + + align:start position:0% +the this is mimic data and if you say + + + align:start position:0% +the this is mimic data and if you say +what's the fraction of abnormal white + + align:start position:0% +what's the fraction of abnormal white + + + align:start position:0% +what's the fraction of abnormal white +blood count values by our so this is + + align:start position:0% +blood count values by our so this is + + + align:start position:0% +blood count values by our so this is +midnight to midnight and each hour + + align:start position:0% +midnight to midnight and each hour + + + align:start position:0% +midnight to midnight and each hour +there's some fraction of these test + + align:start position:0% +there's some fraction of these test + + + align:start position:0% +there's some fraction of these test +results that are abnormal and sure + + align:start position:0% +results that are abnormal and sure + + + align:start position:0% +results that are abnormal and sure +enough what you see is that at five + + align:start position:0% +enough what you see is that at five + + + align:start position:0% +enough what you see is that at five +o'clock in the morning much higher + + align:start position:0% +o'clock in the morning much higher + + + align:start position:0% +o'clock in the morning much higher +fraction of them is abnormal than at 3 + + align:start position:0% +fraction of them is abnormal than at 3 + + + align:start position:0% +fraction of them is abnormal than at 3 +o'clock in the afternoon okay which is + + align:start position:0% +o'clock in the afternoon okay which is + + + align:start position:0% +o'clock in the afternoon okay which is +consistent with Zak's peremptory comment + + align:start position:0% +consistent with Zak's peremptory comment + + + align:start position:0% +consistent with Zak's peremptory comment +about the guy being an idiot so once + + align:start position:0% +about the guy being an idiot so once + + + align:start position:0% +about the guy being an idiot so once +again I said well can we build a really + + align:start position:0% +again I said well can we build a really + + + align:start position:0% +again I said well can we build a really +simple model that predicts who's going + + align:start position:0% +simple model that predicts who's going + + + align:start position:0% +simple model that predicts who's going +to die in the hospital in this case + + align:start position:0% +to die in the hospital in this case + + + align:start position:0% +to die in the hospital in this case +that's the easiest one to predict + + align:start position:0% +that's the easiest one to predict + + + align:start position:0% +that's the easiest one to predict +because I have that data we we could get + + align:start position:0% +because I have that data we we could get + + + align:start position:0% +because I have that data we we could get +three year survival data which is what + + align:start position:0% +three year survival data which is what + + + align:start position:0% +three year survival data which is what +they were looking at but it's harder and + + align:start position:0% +they were looking at but it's harder and + + + align:start position:0% +they were looking at but it's harder and +it runs into sensoring problems of what + + align:start position:0% +it runs into sensoring problems of what + + + align:start position:0% +it runs into sensoring problems of what +happens if the person was hospitalized + + align:start position:0% +happens if the person was hospitalized + + + align:start position:0% +happens if the person was hospitalized +less than three years before the end of + + align:start position:0% +less than three years before the end of + + + align:start position:0% +less than three years before the end of +our data collection period and so on and + + align:start position:0% +our data collection period and so on and + + + align:start position:0% +our data collection period and so on and +so I avoided that but what this is + + align:start position:0% +so I avoided that but what this is + + + align:start position:0% +so I avoided that but what this is +showing you is for each of the hours 0 + + align:start position:0% +showing you is for each of the hours 0 + + + align:start position:0% +showing you is for each of the hours 0 +to 24 what is the the number of + + align:start position:0% +to 24 what is the the number of + + + align:start position:0% +to 24 what is the the number of +measurements and for each of those hours + + align:start position:0% +measurements and for each of those hours + + + align:start position:0% +measurements and for each of those hours +what is the number what is the fraction + + align:start position:0% +what is the number what is the fraction + + + align:start position:0% +what is the number what is the fraction +of those measurements that's abnormal + + align:start position:0% +of those measurements that's abnormal + + + align:start position:0% +of those measurements that's abnormal +okay so I said well let's just throw it + + align:start position:0% +okay so I said well let's just throw it + + + align:start position:0% +okay so I said well let's just throw it +into logistic regression model and what + + align:start position:0% +into logistic regression model and what + + + align:start position:0% +into logistic regression model and what +comes out is something really weird + + align:start position:0% +comes out is something really weird + + + align:start position:0% +comes out is something really weird +which is that a few particular hours are + + align:start position:0% +which is that a few particular hours are + + + align:start position:0% +which is that a few particular hours are +significant but most of them are not and + + align:start position:0% +significant but most of them are not and + + + align:start position:0% +significant but most of them are not and +that looks like noise to me + + align:start position:0% +that looks like noise to me + + + align:start position:0% +that looks like noise to me +right because you wouldn't expect that + + align:start position:0% +right because you wouldn't expect that + + + align:start position:0% +right because you wouldn't expect that +that at at eight o'clock in the morning + + align:start position:0% +that at at eight o'clock in the morning + + + align:start position:0% +that at at eight o'clock in the morning +the the fact that you had something + + align:start position:0% +the the fact that you had something + + + align:start position:0% +the the fact that you had something +measured matters but at nine o'clock in + + align:start position:0% +measured matters but at nine o'clock in + + + align:start position:0% +measured matters but at nine o'clock in +the morning it doesn't that doesn't seem + + align:start position:0% +the morning it doesn't that doesn't seem + + + align:start position:0% +the morning it doesn't that doesn't seem +sensible so I don't think there's enough + + align:start position:0% +sensible so I don't think there's enough + + + align:start position:0% +sensible so I don't think there's enough +signal here and in fact when I looked at + + align:start position:0% +signal here and in fact when I looked at + + + align:start position:0% +signal here and in fact when I looked at +the number of white blood count + + align:start position:0% +the number of white blood count + + + align:start position:0% +the number of white blood count +measurements at night and related to + + align:start position:0% +measurements at night and related to + + + align:start position:0% +measurements at night and related to +mortality so false means people lived + + align:start position:0% +mortality so false means people lived + + + align:start position:0% +mortality so false means people lived +and true means they died but you see + + align:start position:0% +and true means they died but you see + + + align:start position:0% +and true means they died but you see +that there's not a whole lot of + + align:start position:0% +that there's not a whole lot of + + + align:start position:0% +that there's not a whole lot of +difference between the distributions but + + align:start position:0% +difference between the distributions but + + + align:start position:0% +difference between the distributions but +you also see that the number of white + + align:start position:0% +you also see that the number of white + + + align:start position:0% +you also see that the number of white +blood counts is relatively small in this + + align:start position:0% +blood counts is relatively small in this + + + align:start position:0% +blood counts is relatively small in this +database and so I think we just don't + + align:start position:0% +database and so I think we just don't + + + align:start position:0% +database and so I think we just don't +have enough data to take to do it on the + + align:start position:0% +have enough data to take to do it on the + + + align:start position:0% +have enough data to take to do it on the +other hand if you look at a panel of + + align:start position:0% +other hand if you look at a panel of + + + align:start position:0% +other hand if you look at a panel of +different drugs you look at mean values + + align:start position:0% +different drugs you look at mean values + + + align:start position:0% +different drugs you look at mean values +of blood urea nitrogen or calcium + + align:start position:0% +of blood urea nitrogen or calcium + + + align:start position:0% +of blood urea nitrogen or calcium +chloride co2 etc you see that there is + + align:start position:0% +chloride co2 etc you see that there is + + + align:start position:0% +chloride co2 etc you see that there is +variation across time so the there is + + align:start position:0% +variation across time so the there is + + + align:start position:0% +variation across time so the there is +some some sort of variance that's either + + align:start position:0% +some some sort of variance that's either + + + align:start position:0% +some some sort of variance that's either +caused by the diurnal physiology of the + + align:start position:0% +caused by the diurnal physiology of the + + + align:start position:0% +caused by the diurnal physiology of the +human body or by the routine practice of + + align:start position:0% +human body or by the routine practice of + + + align:start position:0% +human body or by the routine practice of +medicine about when people choose to + + align:start position:0% +medicine about when people choose to + + + align:start position:0% +medicine about when people choose to +take lab measurements and in fact if you + + align:start position:0% +take lab measurements and in fact if you + + + align:start position:0% +take lab measurements and in fact if you +look at the fraction of high and low lab + + align:start position:0% +look at the fraction of high and low lab + + + align:start position:0% +look at the fraction of high and low lab +values they do vary by hour and in + + align:start position:0% +values they do vary by hour and in + + + align:start position:0% +values they do vary by hour and in +particular if you look at white blood + + align:start position:0% +particular if you look at white blood + + + align:start position:0% +particular if you look at white blood +counts you see that the fraction of high + + align:start position:0% +counts you see that the fraction of high + + + align:start position:0% +counts you see that the fraction of high +values goes up at night and the fraction + + align:start position:0% +values goes up at night and the fraction + + + align:start position:0% +values goes up at night and the fraction +of low values goes down at night which + + align:start position:0% +of low values goes down at night which + + + align:start position:0% +of low values goes down at night which +is consistent with what they saw as well + + align:start position:0% +is consistent with what they saw as well + + + align:start position:0% +is consistent with what they saw as well +there's another way to measure it which + + align:start position:0% +there's another way to measure it which + + + align:start position:0% +there's another way to measure it which +is the instead of using normal ranges + + align:start position:0% +is the instead of using normal ranges + + + align:start position:0% +is the instead of using normal ranges +the lab actually gives you a call that + + align:start position:0% +the lab actually gives you a call that + + + align:start position:0% +the lab actually gives you a call that +says is this value normal + + align:start position:0% +says is this value normal + + + align:start position:0% +says is this value normal +low or high and we can use that that's a + + align:start position:0% +low or high and we can use that that's a + + + align:start position:0% +low or high and we can use that that's a +little bit more subtle because it + + align:start position:0% +little bit more subtle because it + + + align:start position:0% +little bit more subtle because it +depends on on calibration of the + + align:start position:0% +depends on on calibration of the + + + align:start position:0% +depends on on calibration of the +equipment and is updated as the + + align:start position:0% +equipment and is updated as the + + + align:start position:0% +equipment and is updated as the +calibration changes so that's probably a + + align:start position:0% +calibration changes so that's probably a + + + align:start position:0% +calibration changes so that's probably a +little bit more accurate but you see + + align:start position:0% +little bit more accurate but you see + + + align:start position:0% +little bit more accurate but you see +essentially the same phenomenon here but + + align:start position:0% +essentially the same phenomenon here but + + + align:start position:0% +essentially the same phenomenon here but +if you look at the distributions of when + + align:start position:0% +if you look at the distributions of when + + + align:start position:0% +if you look at the distributions of when +measurements are done that turn out to + + align:start position:0% +measurements are done that turn out to + + + align:start position:0% +measurements are done that turn out to +be normal versus when they turn out to + + align:start position:0% +be normal versus when they turn out to + + + align:start position:0% +be normal versus when they turn out to +be abnormal there's a lot of similarity + + align:start position:0% +be abnormal there's a lot of similarity + + + align:start position:0% +be abnormal there's a lot of similarity +between the normal and the abnormal + + align:start position:0% +between the normal and the abnormal + + + align:start position:0% +between the normal and the abnormal +curves of when those measurements are + + align:start position:0% +curves of when those measurements are + + + align:start position:0% +curves of when those measurements are +taken so we're not seeing that okay let + + align:start position:0% +taken so we're not seeing that okay let + + + align:start position:0% +taken so we're not seeing that okay let +me race through to the end this is my + + align:start position:0% +me race through to the end this is my + + + align:start position:0% +me race through to the end this is my +heartbeat from my watch you can actually + + align:start position:0% +heartbeat from my watch you can actually + + + align:start position:0% +heartbeat from my watch you can actually +download the stuff and put it in your + + align:start position:0% +download the stuff and put it in your + + + align:start position:0% +download the stuff and put it in your +favorite analysis engine and take a look + + align:start position:0% +favorite analysis engine and take a look + + + align:start position:0% +favorite analysis engine and take a look +so here I was running across the Harvard + + align:start position:0% +so here I was running across the Harvard + + + align:start position:0% +so here I was running across the Harvard +bridge and if you look at my heart rate + + align:start position:0% +bridge and if you look at my heart rate + + + align:start position:0% +bridge and if you look at my heart rate +variability over the 30 seconds or so + + align:start position:0% +variability over the 30 seconds or so + + + align:start position:0% +variability over the 30 seconds or so +you see that the intra beat interval + + align:start position:0% +you see that the intra beat interval + + + align:start position:0% +you see that the intra beat interval +ranges from about 550 to about six + + align:start position:0% +ranges from about 550 to about six + + + align:start position:0% +ranges from about 550 to about six +hundred and thirty six hundred and + + align:start position:0% +hundred and thirty six hundred and + + + align:start position:0% +hundred and thirty six hundred and +whatever 20 milliseconds and so you + + align:start position:0% +whatever 20 milliseconds and so you + + + align:start position:0% +whatever 20 milliseconds and so you +could calculate my heart rate + + align:start position:0% +could calculate my heart rate + + + align:start position:0% +could calculate my heart rate +variability which is thought to be an + + align:start position:0% +variability which is thought to be an + + + align:start position:0% +variability which is thought to be an +indicator of heart health and so on you + + align:start position:0% +indicator of heart health and so on you + + + align:start position:0% +indicator of heart health and so on you +can calculate that I was running at a + + align:start position:0% +can calculate that I was running at a + + + align:start position:0% +can calculate that I was running at a +pace of about a hundred my heart was + + align:start position:0% +pace of about a hundred my heart was + + + align:start position:0% +pace of about a hundred my heart was +beating at a pace of about a hundred + + align:start position:0% +beating at a pace of about a hundred + + + align:start position:0% +beating at a pace of about a hundred +beats per minute so you know there's all + + align:start position:0% +beats per minute so you know there's all + + + align:start position:0% +beats per minute so you know there's all +sorts of information like that available + + align:start position:0% +sorts of information like that available + + + align:start position:0% +sorts of information like that available +now as I said I'm not going to get into + + align:start position:0% +now as I said I'm not going to get into + + + align:start position:0% +now as I said I'm not going to get into +this today but this was a very + + align:start position:0% +this today but this was a very + + + align:start position:0% +this today but this was a very +successful recently published paper + + align:start position:0% +successful recently published paper + + + align:start position:0% +successful recently published paper +where they're able to take a look at at + + align:start position:0% +where they're able to take a look at at + + + align:start position:0% +where they're able to take a look at at +images of the lung so this is a + + align:start position:0% +images of the lung so this is a + + + align:start position:0% +images of the lung so this is a +transverse scan of the of the lung and + + align:start position:0% +transverse scan of the of the lung and + + + align:start position:0% +transverse scan of the of the lung and +they have a deep learning machine that + + align:start position:0% +they have a deep learning machine that + + + align:start position:0% +they have a deep learning machine that +is able to identify these two yellow + + align:start position:0% +is able to identify these two yellow + + + align:start position:0% +is able to identify these two yellow +mark things as pulmonary emboli as + + align:start position:0% +mark things as pulmonary emboli as + + + align:start position:0% +mark things as pulmonary emboli as +opposed to these other things that are + + align:start position:0% +opposed to these other things that are + + + align:start position:0% +opposed to these other things that are +just random flecks in the tissue and I + + align:start position:0% +just random flecks in the tissue and I + + + align:start position:0% +just random flecks in the tissue and I +can't do that + + align:start position:0% +can't do that + + + align:start position:0% +can't do that +my eyeball maybe a good radiologist + + align:start position:0% +my eyeball maybe a good radiologist + + + align:start position:0% +my eyeball maybe a good radiologist +might be able to but this is claimed in + + align:start position:0% +might be able to but this is claimed in + + + align:start position:0% +might be able to but this is claimed in +the paper to outperform decent + + align:start position:0% +the paper to outperform decent + + + align:start position:0% +the paper to outperform decent +radiologists already this was one of the + + align:start position:0% +radiologists already this was one of the + + + align:start position:0% +radiologists already this was one of the +articles that led geoff hinton to make + + align:start position:0% +articles that led geoff hinton to make + + + align:start position:0% +articles that led geoff hinton to make +this rather stupid pronouncement that + + align:start position:0% +this rather stupid pronouncement that + + + align:start position:0% +this rather stupid pronouncement that +said tell your children not to become + + align:start position:0% +said tell your children not to become + + + align:start position:0% +said tell your children not to become +radiologists because the profession will + + align:start position:0% +radiologists because the profession will + + + align:start position:0% +radiologists because the profession will +be over by the time they get fully + + align:start position:0% +be over by the time they get fully + + + align:start position:0% +be over by the time they get fully +trained which i don't believe they may + + align:start position:0% +trained which i don't believe they may + + + align:start position:0% +trained which i don't believe they may +do different things but but they won't + + align:start position:0% +do different things but but they won't + + + align:start position:0% +do different things but but they won't +go away this was a slide from ron + + align:start position:0% +go away this was a slide from ron + + + align:start position:0% +go away this was a slide from ron +kookiness at the Brigham and they're + + align:start position:0% +kookiness at the Brigham and they're + + + align:start position:0% +kookiness at the Brigham and they're +using automated techniques of analyzing + + align:start position:0% +using automated techniques of analyzing + + + align:start position:0% +using automated techniques of analyzing +white matter in order to identify lupus + + align:start position:0% +white matter in order to identify lupus + + + align:start position:0% +white matter in order to identify lupus +lesions so lupus is a bad disease that + + align:start position:0% +lesions so lupus is a bad disease that + + + align:start position:0% +lesions so lupus is a bad disease that +shows up in these magnetic resonance + + align:start position:0% +shows up in these magnetic resonance + + + align:start position:0% +shows up in these magnetic resonance +images in certain ways the last thing I + + align:start position:0% +images in certain ways the last thing I + + + align:start position:0% +images in certain ways the last thing I +want to talk about today is notes so my + + align:start position:0% +want to talk about today is notes so my + + + align:start position:0% +want to talk about today is notes so my +students stood a little exercise last + + align:start position:0% +students stood a little exercise last + + + align:start position:0% +students stood a little exercise last +semester where we tried to see how good + + align:start position:0% +semester where we tried to see how good + + + align:start position:0% +semester where we tried to see how good +is the average ape namely a member of my + + align:start position:0% +is the average ape namely a member of my + + + align:start position:0% +is the average ape namely a member of my +research group at predicting mortality + + align:start position:0% +research group at predicting mortality + + + align:start position:0% +research group at predicting mortality +okay and so we took a bunch of cases + + align:start position:0% +okay and so we took a bunch of cases + + + align:start position:0% +okay and so we took a bunch of cases +from the mimic data set blind it to the + + align:start position:0% +from the mimic data set blind it to the + + + align:start position:0% +from the mimic data set blind it to the +question of whether the person lived or + + align:start position:0% +question of whether the person lived or + + + align:start position:0% +question of whether the person lived or +died we gave the data to people in a + + align:start position:0% +died we gave the data to people in a + + + align:start position:0% +died we gave the data to people in a +kind of visualization tool sort of like + + align:start position:0% +kind of visualization tool sort of like + + + align:start position:0% +kind of visualization tool sort of like +the one that I showed you earlier that + + align:start position:0% +the one that I showed you earlier that + + + align:start position:0% +the one that I showed you earlier that +summarizes the case and then also gave + + align:start position:0% +summarizes the case and then also gave + + + align:start position:0% +summarizes the case and then also gave +people access to the notes the + + align:start position:0% +people access to the notes the + + + align:start position:0% +people access to the notes the +de-identified notes about those cases to + + align:start position:0% +de-identified notes about those cases to + + + align:start position:0% +de-identified notes about those cases to +see whether people could predict better + + align:start position:0% +see whether people could predict better + + + align:start position:0% +see whether people could predict better +than a coin flip whether somebody was + + align:start position:0% +than a coin flip whether somebody was + + + align:start position:0% +than a coin flip whether somebody was +going to live or die and the answer is + + align:start position:0% +going to live or die and the answer is + + + align:start position:0% +going to live or die and the answer is +yes slightly better okay not immensely + + align:start position:0% +yes slightly better okay not immensely + + + align:start position:0% +yes slightly better okay not immensely +better but slightly better and + + align:start position:0% +better but slightly better and + + + align:start position:0% +better but slightly better and +furthermore it looks like by giving them + + align:start position:0% +furthermore it looks like by giving them + + + align:start position:0% +furthermore it looks like by giving them +feedback so as they're looking at these + + align:start position:0% +feedback so as they're looking at these + + + align:start position:0% +feedback so as they're looking at these +cases and trying + + align:start position:0% +cases and trying + + + align:start position:0% +cases and trying +to make the prediction they make a + + align:start position:0% +to make the prediction they make a + + + align:start position:0% +to make the prediction they make a +prediction you tell them if they were + + align:start position:0% +prediction you tell them if they were + + + align:start position:0% +prediction you tell them if they were +right or wrong we learn and so we get + + align:start position:0% +right or wrong we learn and so we get + + + align:start position:0% +right or wrong we learn and so we get +slightly better than slightly better + + align:start position:0% +slightly better than slightly better + + + align:start position:0% +slightly better than slightly better +than random right it's kind of + + align:start position:0% +than random right it's kind of + + + align:start position:0% +than random right it's kind of +interesting okay + + align:start position:0% +interesting okay + + + align:start position:0% +interesting okay +so one of the things I discovered is + + align:start position:0% +so one of the things I discovered is + + + align:start position:0% +so one of the things I discovered is +that at least when I was playing the + + align:start position:0% +that at least when I was playing the + + + align:start position:0% +that at least when I was playing the +monkey in this exercise I found the + + align:start position:0% +monkey in this exercise I found the + + + align:start position:0% +monkey in this exercise I found the +notes to be immensely useful much more + + align:start position:0% +notes to be immensely useful much more + + + align:start position:0% +notes to be immensely useful much more +useful than the trendlines of laboratory + + align:start position:0% +useful than the trendlines of laboratory + + + align:start position:0% +useful than the trendlines of laboratory +data partly it's because I'm used to + + align:start position:0% +data partly it's because I'm used to + + + align:start position:0% +data partly it's because I'm used to +reading English I'm not so used to + + align:start position:0% +reading English I'm not so used to + + + align:start position:0% +reading English I'm not so used to +reading graphs of laboratory data but + + align:start position:0% +reading graphs of laboratory data but + + + align:start position:0% +reading graphs of laboratory data but +part of it is that there's a level of + + align:start position:0% +part of it is that there's a level of + + + align:start position:0% +part of it is that there's a level of +human understanding that is transmitted + + align:start position:0% +human understanding that is transmitted + + + align:start position:0% +human understanding that is transmitted +in the nursing notes and in the + + align:start position:0% +in the nursing notes and in the + + + align:start position:0% +in the nursing notes and in the +discharge summaries and so on that you + + align:start position:0% +discharge summaries and so on that you + + + align:start position:0% +discharge summaries and so on that you +don't get from just looking at raw data + + align:start position:0% +don't get from just looking at raw data + + + align:start position:0% +don't get from just looking at raw data +and so there is very much the sense + + align:start position:0% +and so there is very much the sense + + + align:start position:0% +and so there is very much the sense +which we're going to talk about in a + + align:start position:0% +which we're going to talk about in a + + + align:start position:0% +which we're going to talk about in a +couple of weeks of how can we take take + + align:start position:0% +couple of weeks of how can we take take + + + align:start position:0% +couple of weeks of how can we take take +advantage of that information extract it + + align:start position:0% +advantage of that information extract it + + + align:start position:0% +advantage of that information extract it +and use it in the kinds of modeling that + + align:start position:0% +and use it in the kinds of modeling that + + + align:start position:0% +and use it in the kinds of modeling that +we want to do so in mimic if you look we + + align:start position:0% +we want to do so in mimic if you look we + + + align:start position:0% +we want to do so in mimic if you look we +have nursing notes and radiology reports + + align:start position:0% +have nursing notes and radiology reports + + + align:start position:0% +have nursing notes and radiology reports +and more nursing notes and + + align:start position:0% +and more nursing notes and + + + align:start position:0% +and more nursing notes and +electrocardiogram reports and doctors + + align:start position:0% +electrocardiogram reports and doctors + + + align:start position:0% +electrocardiogram reports and doctors +notes and discharge some reason + + align:start position:0% +notes and discharge some reason + + + align:start position:0% +notes and discharge some reason +echocardiogram is respiratory etc and if + + align:start position:0% +echocardiogram is respiratory etc and if + + + align:start position:0% +echocardiogram is respiratory etc and if +you look at the distribution of the + + align:start position:0% +you look at the distribution of the + + + align:start position:0% +you look at the distribution of the +length of these these are unfortunately + + align:start position:0% +length of these these are unfortunately + + + align:start position:0% +length of these these are unfortunately +not on the same scale but the discharge + + align:start position:0% +not on the same scale but the discharge + + + align:start position:0% +not on the same scale but the discharge +summary is the thing that's written at + + align:start position:0% +summary is the thing that's written at + + + align:start position:0% +summary is the thing that's written at +the time you leave the hospital so this + + align:start position:0% +the time you leave the hospital so this + + + align:start position:0% +the time you leave the hospital so this +is sort of the summary of everything + + align:start position:0% +is sort of the summary of everything + + + align:start position:0% +is sort of the summary of everything +that happened to you during your + + align:start position:0% +that happened to you during your + + + align:start position:0% +that happened to you during your +hospitalization and it's long so you + + align:start position:0% +hospitalization and it's long so you + + + align:start position:0% +hospitalization and it's long so you +know it goes up to like 30,000 + + align:start position:0% +know it goes up to like 30,000 + + + align:start position:0% +know it goes up to like 30,000 +characters you know it's a small it's a + + align:start position:0% +characters you know it's a small it's a + + + align:start position:0% +characters you know it's a small it's a +short story not not so short short story + + align:start position:0% +short story not not so short short story + + + align:start position:0% +short story not not so short short story +nursing notes tend to be shorter they + + align:start position:0% +nursing notes tend to be shorter they + + + align:start position:0% +nursing notes tend to be shorter they +run up to about 3,000 characters this + + align:start position:0% +run up to about 3,000 characters this + + + align:start position:0% +run up to about 3,000 characters this +other set of nursing notes which I think + + align:start position:0% +other set of nursing notes which I think + + + align:start position:0% +other set of nursing notes which I think +is comes from the other system is a + + align:start position:0% +is comes from the other system is a + + + align:start position:0% +is comes from the other system is a +little bit longer it goes up to about + + align:start position:0% +little bit longer it goes up to about + + + align:start position:0% +little bit longer it goes up to about +5,000 doctor's notes are a little bit + + align:start position:0% +5,000 doctor's notes are a little bit + + + align:start position:0% +5,000 doctor's notes are a little bit +longer yet they go up to about 10:15 + + align:start position:0% +longer yet they go up to about 10:15 + + + align:start position:0% +longer yet they go up to about 10:15 +thousand characters typically and there + + align:start position:0% +thousand characters typically and there + + + align:start position:0% +thousand characters typically and there +are various other kinds of notes so I + + align:start position:0% +are various other kinds of notes so I + + + align:start position:0% +are various other kinds of notes so I +just wanted to show you a few of these + + align:start position:0% +just wanted to show you a few of these + + + align:start position:0% +just wanted to show you a few of these +here's a brief nursing note so this is a + + align:start position:0% +here's a brief nursing note so this is a + + + align:start position:0% +here's a brief nursing note so this is a +patient who is hypotensive but not in + + align:start position:0% +patient who is hypotensive but not in + + + align:start position:0% +patient who is hypotensive but not in +shock patient remains on this drug drip + + align:start position:0% +shock patient remains on this drug drip + + + align:start position:0% +shock patient remains on this drug drip +at point 75 micrograms per kilogram per + + align:start position:0% +at point 75 micrograms per kilogram per + + + align:start position:0% +at point 75 micrograms per kilogram per +minute + + align:start position:0% +minute + + + align:start position:0% +minute +no titration needed at this time their + + align:start position:0% +no titration needed at this time their + + + align:start position:0% +no titration needed at this time their +blood pressure is stable at more than a + + align:start position:0% +blood pressure is stable at more than a + + + align:start position:0% +blood pressure is stable at more than a +hundred the mean arterial pressure is 65 + + align:start position:0% +hundred the mean arterial pressure is 65 + + + align:start position:0% +hundred the mean arterial pressure is 65 +greater than 65 weaned them from this + + align:start position:0% +greater than 65 weaned them from this + + + align:start position:0% +greater than 65 weaned them from this +drug presumably if if it's tolerated a + + align:start position:0% +drug presumably if if it's tolerated a + + + align:start position:0% +drug presumably if if it's tolerated a +wound infection so anterior groin area + + align:start position:0% +wound infection so anterior groin area + + + align:start position:0% +wound infection so anterior groin area +open and losing moderate amounts of thin + + align:start position:0% +open and losing moderate amounts of thin + + + align:start position:0% +open and losing moderate amounts of thin +pink pink tinged serous fluid patients + + align:start position:0% +pink pink tinged serous fluid patients + + + align:start position:0% +pink pink tinged serous fluid patients +tooling with small amounts of stool on + + align:start position:0% +tooling with small amounts of stool on + + + align:start position:0% +tooling with small amounts of stool on +something and dangerously close to the + + align:start position:0% +something and dangerously close to the + + + align:start position:0% +something and dangerously close to the +open wound etc so this is sort of the + + align:start position:0% +open wound etc so this is sort of the + + + align:start position:0% +open wound etc so this is sort of the +nurse's snapshot she just went in saw + + align:start position:0% +nurse's snapshot she just went in saw + + + align:start position:0% +nurse's snapshot she just went in saw +the patient by the way I say she but you + + align:start position:0% +the patient by the way I say she but you + + + align:start position:0% +the patient by the way I say she but you +know probably a vast majority of nurses + + align:start position:0% +know probably a vast majority of nurses + + + align:start position:0% +know probably a vast majority of nurses +in Boston area hospitals really are + + align:start position:0% +in Boston area hospitals really are + + + align:start position:0% +in Boston area hospitals really are +women but there are some male nurses and + + align:start position:0% +women but there are some male nurses and + + + align:start position:0% +women but there are some male nurses and +we'll record sort of a snapshot of + + align:start position:0% +we'll record sort of a snapshot of + + + align:start position:0% +we'll record sort of a snapshot of +what's going on with the patient what + + align:start position:0% +what's going on with the patient what + + + align:start position:0% +what's going on with the patient what +are the concerns in principle this is + + align:start position:0% +are the concerns in principle this is + + + align:start position:0% +are the concerns in principle this is +going to be useful not only as a part of + + align:start position:0% +going to be useful not only as a part of + + + align:start position:0% +going to be useful not only as a part of +the medical record but also when this + + align:start position:0% +the medical record but also when this + + + align:start position:0% +the medical record but also when this +nurse goes off shift and the next nurse + + align:start position:0% +nurse goes off shift and the next nurse + + + align:start position:0% +nurse goes off shift and the next nurse +comes on shift then this is a recording + + align:start position:0% +comes on shift then this is a recording + + + align:start position:0% +comes on shift then this is a recording +of what the state of the patient was the + + align:start position:0% +of what the state of the patient was the + + + align:start position:0% +of what the state of the patient was the +last time they were seen by by the nurse + + align:start position:0% +last time they were seen by by the nurse + + + align:start position:0% +last time they were seen by by the nurse +in reality the nurses tend to tell each + + align:start position:0% +in reality the nurses tend to tell each + + + align:start position:0% +in reality the nurses tend to tell each +other verbally rather than relying on + + align:start position:0% +other verbally rather than relying on + + + align:start position:0% +other verbally rather than relying on +the written version I remember one time + + align:start position:0% +the written version I remember one time + + + align:start position:0% +the written version I remember one time +talking to a nurse in an intensive care + + align:start position:0% +talking to a nurse in an intensive care + + + align:start position:0% +talking to a nurse in an intensive care +unit in another part of the country and + + align:start position:0% +unit in another part of the country and + + + align:start position:0% +unit in another part of the country and +I said so whoever reads your notes and + + align:start position:0% +I said so whoever reads your notes and + + + align:start position:0% +I said so whoever reads your notes and +she says quality assurance officers so + + align:start position:0% +she says quality assurance officers so + + + align:start position:0% +she says quality assurance officers so +the hospital has people responsible for + + align:start position:0% +the hospital has people responsible for + + + align:start position:0% +the hospital has people responsible for +trying to assess the quality of care + + align:start position:0% +trying to assess the quality of care + + + align:start position:0% +trying to assess the quality of care +they're giving and lawyers when there's + + align:start position:0% +they're giving and lawyers when there's + + + align:start position:0% +they're giving and lawyers when there's +a lawsuit + + align:start position:0% +a lawsuit + + + align:start position:0% +a lawsuit +and she was very happy because she had + + align:start position:0% +and she was very happy because she had + + + align:start position:0% +and she was very happy because she had +saved the hospital ten million dollars + + align:start position:0% +saved the hospital ten million dollars + + + align:start position:0% +saved the hospital ten million dollars +by having carefully recorded that some + + align:start position:0% +by having carefully recorded that some + + + align:start position:0% +by having carefully recorded that some +procedure had been done to a patient who + + align:start position:0% +procedure had been done to a patient who + + + align:start position:0% +procedure had been done to a patient who +then had a bad outcome and was suing the + + align:start position:0% +then had a bad outcome and was suing the + + + align:start position:0% +then had a bad outcome and was suing the +hospital for their neglect and not + + align:start position:0% +hospital for their neglect and not + + + align:start position:0% +hospital for their neglect and not +having done this but because it was in + + align:start position:0% +having done this but because it was in + + + align:start position:0% +having done this but because it was in +the note that was proof that it actually + + align:start position:0% +the note that was proof that it actually + + + align:start position:0% +the note that was proof that it actually +had been done and therefore the hospital + + align:start position:0% +had been done and therefore the hospital + + + align:start position:0% +had been done and therefore the hospital +wasn't liable so but there's a lot of + + align:start position:0% +wasn't liable so but there's a lot of + + + align:start position:0% +wasn't liable so but there's a lot of +information in here now I'm going to + + align:start position:0% +information in here now I'm going to + + + align:start position:0% +information in here now I'm going to +show you many pages of a typical + + align:start position:0% +show you many pages of a typical + + + align:start position:0% +show you many pages of a typical +discharge summary so this is somebody on + + align:start position:0% +discharge summary so this is somebody on + + + align:start position:0% +discharge summary so this is somebody on +the surgery service who came in + + align:start position:0% +the surgery service who came in + + + align:start position:0% +the surgery service who came in +complaining of leg leg pain redness and + + align:start position:0% +complaining of leg leg pain redness and + + + align:start position:0% +complaining of leg leg pain redness and +swelling secondary to infection of the + + align:start position:0% +swelling secondary to infection of the + + + align:start position:0% +swelling secondary to infection of the +left femoral pop pop little bypass so + + align:start position:0% +left femoral pop pop little bypass so + + + align:start position:0% +left femoral pop pop little bypass so +she had surgery I think she now female + + align:start position:0% +she had surgery I think she now female + + + align:start position:0% +she had surgery I think she now female +she had surgery which didn't heal well + + align:start position:0% +she had surgery which didn't heal well + + + align:start position:0% +she had surgery which didn't heal well +so major surgical or invasive procedure + + align:start position:0% +so major surgical or invasive procedure + + + align:start position:0% +so major surgical or invasive procedure +incision and drainage and pulse + + align:start position:0% +incision and drainage and pulse + + + align:start position:0% +incision and drainage and pulse +irrigation of the left groin and left + + align:start position:0% +irrigation of the left groin and left + + + align:start position:0% +irrigation of the left groin and left +above knee popliteal site incisions with + + align:start position:0% +above knee popliteal site incisions with + + + align:start position:0% +above knee popliteal site incisions with +exploration of bypass graft and excision + + align:start position:0% +exploration of bypass graft and excision + + + align:start position:0% +exploration of bypass graft and excision +of the entire left common femoral artery + + align:start position:0% +of the entire left common femoral artery + + + align:start position:0% +of the entire left common femoral artery +- above knee blah blah blah blah blah + + align:start position:0% +- above knee blah blah blah blah blah + + + align:start position:0% +- above knee blah blah blah blah blah +blah so this is what they did history of + + align:start position:0% +blah so this is what they did history of + + + align:start position:0% +blah so this is what they did history of +the present illness she's a 45 year old + + align:start position:0% +the present illness she's a 45 year old + + + align:start position:0% +the present illness she's a 45 year old +woman who underwent a left femoral ache + + align:start position:0% +woman who underwent a left femoral ache + + + align:start position:0% +woman who underwent a left femoral ache +a doctor or something or other with PTFE + + align:start position:0% +a doctor or something or other with PTFE + + + align:start position:0% +a doctor or something or other with PTFE +whatever that is over a month ago on a + + align:start position:0% +whatever that is over a month ago on a + + + align:start position:0% +whatever that is over a month ago on a +certain date by the way these bracket + + align:start position:0% +certain date by the way these bracket + + + align:start position:0% +certain date by the way these bracket +asterisk things are where we've taken + + align:start position:0% +asterisk things are where we've taken + + + align:start position:0% +asterisk things are where we've taken +out identifying information from the + + align:start position:0% +out identifying information from the + + + align:start position:0% +out identifying information from the +record she had been doing well + + align:start position:0% +record she had been doing well + + + align:start position:0% +record she had been doing well +postoperatively and was seen in the + + align:start position:0% +postoperatively and was seen in the + + + align:start position:0% +postoperatively and was seen in the +clinic six days prior to presentation at + + align:start position:0% +clinic six days prior to presentation at + + + align:start position:0% +clinic six days prior to presentation at +this time she acutely developed nausea + + align:start position:0% +this time she acutely developed nausea + + + align:start position:0% +this time she acutely developed nausea +vomiting fevers and progressive redness + + align:start position:0% +vomiting fevers and progressive redness + + + align:start position:0% +vomiting fevers and progressive redness +swelling pain of her left thigh etc okay + + align:start position:0% +swelling pain of her left thigh etc okay + + + align:start position:0% +swelling pain of her left thigh etc okay +so that's just page one of many pages + + align:start position:0% +so that's just page one of many pages + + + align:start position:0% +so that's just page one of many pages +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +these information fields there's no help + + align:start position:0% +these information fields there's no help + + + align:start position:0% +these information fields there's no help +is there's no heart of impedes if you + + align:start position:0% +is there's no heart of impedes if you + + + align:start position:0% +is there's no heart of impedes if you +type a patient's name we're not in this + + align:start position:0% +type a patient's name we're not in this + + + align:start position:0% +type a patient's name we're not in this +system there there are people Henrich + + align:start position:0% +system there there are people Henrich + + + align:start position:0% +system there there are people Henrich +way at Mass General spent ten years + + align:start position:0% +way at Mass General spent ten years + + + align:start position:0% +way at Mass General spent ten years +building a system that had autocomplete + + align:start position:0% +building a system that had autocomplete + + + align:start position:0% +building a system that had autocomplete +and so on and some doctors liked it and + + align:start position:0% +and so on and some doctors liked it and + + + align:start position:0% +and so on and some doctors liked it and +some doctors hated it and the MGH threw + + align:start position:0% +some doctors hated it and the MGH threw + + + align:start position:0% +some doctors hated it and the MGH threw +out all of their old systems in order to + + align:start position:0% +out all of their old systems in order to + + + align:start position:0% +out all of their old systems in order to +buy epic and so it's gone was like 10 + + align:start position:0% +buy epic and so it's gone was like 10 + + + align:start position:0% +buy epic and so it's gone was like 10 +years of work down the drain but it was + + align:start position:0% +years of work down the drain but it was + + + align:start position:0% +years of work down the drain but it was +not a spectacular success so because + + align:start position:0% +not a spectacular success so because + + + align:start position:0% +not a spectacular success so because +whenever you have like autocomplete you + + align:start position:0% +whenever you have like autocomplete you + + + align:start position:0% +whenever you have like autocomplete you +have to anticipate every possible answer + + align:start position:0% +have to anticipate every possible answer + + + align:start position:0% +have to anticipate every possible answer +and people are very creative and they + + align:start position:0% +and people are very creative and they + + + align:start position:0% +and people are very creative and they +always want to type something that you + + align:start position:0% +always want to type something that you + + + align:start position:0% +always want to type something that you +didn't anticipate so it's it's hard to + + align:start position:0% +didn't anticipate so it's it's hard to + + + align:start position:0% +didn't anticipate so it's it's hard to +support it epic is a big company that + + align:start position:0% +support it epic is a big company that + + + align:start position:0% +support it epic is a big company that +has been winning all the recent contests + + align:start position:0% +has been winning all the recent contests + + + align:start position:0% +has been winning all the recent contests +for installing electronic medical record + + align:start position:0% +for installing electronic medical record + + + align:start position:0% +for installing electronic medical record +systems remember in my last lecture I + + align:start position:0% +systems remember in my last lecture I + + + align:start position:0% +systems remember in my last lecture I +showed that we're reaching about a + + align:start position:0% +showed that we're reaching about a + + + align:start position:0% +showed that we're reaching about a +hundred percent saturation so they've + + align:start position:0% +hundred percent saturation so they've + + + align:start position:0% +hundred percent saturation so they've +been winning a lot of the of the of the + + align:start position:0% +been winning a lot of the of the of the + + + align:start position:0% +been winning a lot of the of the of the +installation deals and they're getting a + + align:start position:0% +installation deals and they're getting a + + + align:start position:0% +installation deals and they're getting a +lot of the subsidy the estimate I heard + + align:start position:0% +lot of the subsidy the estimate I heard + + + align:start position:0% +lot of the subsidy the estimate I heard +was that Partners HealthCare which is + + align:start position:0% +was that Partners HealthCare which is + + + align:start position:0% +was that Partners HealthCare which is +MGH of the Brigham and a couple of other + + align:start position:0% +MGH of the Brigham and a couple of other + + + align:start position:0% +MGH of the Brigham and a couple of other +hospitals spent somewhere on the order + + align:start position:0% +hospitals spent somewhere on the order + + + align:start position:0% +hospitals spent somewhere on the order +of two billion dollars installing the + + align:start position:0% +of two billion dollars installing the + + + align:start position:0% +of two billion dollars installing the +system so that included all the + + align:start position:0% +system so that included all the + + + align:start position:0% +system so that included all the +customizations and all the training and + + align:start position:0% +customizations and all the training and + + + align:start position:0% +customizations and all the training and +all the administrative stuff that went + + align:start position:0% +all the administrative stuff that went + + + align:start position:0% +all the administrative stuff that went +with it but that's a huge amount of + + align:start position:0% +with it but that's a huge amount of + + + align:start position:0% +with it but that's a huge amount of +money okay so we have past medical + + align:start position:0% +money okay so we have past medical + + + align:start position:0% +money okay so we have past medical +history one pack a day smoker abused + + align:start position:0% +history one pack a day smoker abused + + + align:start position:0% +history one pack a day smoker abused +cocaine but she stopped six months ago + + align:start position:0% +cocaine but she stopped six months ago + + + align:start position:0% +cocaine but she stopped six months ago +has asthma type two diabetes + + align:start position:0% +has asthma type two diabetes + + + align:start position:0% +has asthma type two diabetes +social history family history these are + + align:start position:0% +social history family history these are + + + align:start position:0% +social history family history these are +the physical exam results + + align:start position:0% +the physical exam results + + + align:start position:0% +the physical exam results +so it's giving you a lot of information + + align:start position:0% +so it's giving you a lot of information + + + align:start position:0% +so it's giving you a lot of information +about the person description of the + + align:start position:0% +about the person description of the + + + align:start position:0% +about the person description of the +wound down at the bottom pertinent lab + + align:start position:0% +wound down at the bottom pertinent lab + + + align:start position:0% +wound down at the bottom pertinent lab +results so these are copied out of the + + align:start position:0% +results so these are copied out of the + + + align:start position:0% +results so these are copied out of the +laboratory tables yeah sorry yeah yeah + + align:start position:0% +laboratory tables yeah sorry yeah yeah + + + align:start position:0% +laboratory tables yeah sorry yeah yeah +the the identification technology here + + align:start position:0% +the the identification technology here + + + align:start position:0% +the the identification technology here +maintains the relative dates but not the + + align:start position:0% +maintains the relative dates but not the + + + align:start position:0% +maintains the relative dates but not the +absolute dates so these are results + + align:start position:0% +absolute dates so these are results + + + align:start position:0% +absolute dates so these are results +again copied out of the laboratory + + align:start position:0% +again copied out of the laboratory + + + align:start position:0% +again copied out of the laboratory +database in into the discharge summary + + align:start position:0% +database in into the discharge summary + + + align:start position:0% +database in into the discharge summary +brief Hospital course and then a review + + align:start position:0% +brief Hospital course and then a review + + + align:start position:0% +brief Hospital course and then a review +of systems so what's going on + + align:start position:0% +of systems so what's going on + + + align:start position:0% +of systems so what's going on +neurologically cardiovascular pulmonary + + align:start position:0% +neurologically cardiovascular pulmonary + + + align:start position:0% +neurologically cardiovascular pulmonary +gi/gu etcetera infectious disease + + align:start position:0% +gi/gu etcetera infectious disease + + + align:start position:0% +gi/gu etcetera infectious disease +endocrine hematology prophylaxis and at + + align:start position:0% +endocrine hematology prophylaxis and at + + + align:start position:0% +endocrine hematology prophylaxis and at +the time of discharge the patient was + + align:start position:0% +the time of discharge the patient was + + + align:start position:0% +the time of discharge the patient was +doing well no fever and stable vital + + align:start position:0% +doing well no fever and stable vital + + + align:start position:0% +doing well no fever and stable vital +signs tolerating a regular diet + + align:start position:0% +signs tolerating a regular diet + + + align:start position:0% +signs tolerating a regular diet +ambulating waiting without assistance + + align:start position:0% +ambulating waiting without assistance + + + align:start position:0% +ambulating waiting without assistance +and pain was well controlled medications + + align:start position:0% +and pain was well controlled medications + + + align:start position:0% +and pain was well controlled medications +on admission so this was the medication + + align:start position:0% +on admission so this was the medication + + + align:start position:0% +on admission so this was the medication +reconciliation discharge medications so + + align:start position:0% +reconciliation discharge medications so + + + align:start position:0% +reconciliation discharge medications so +this is what she's being sent home on + + align:start position:0% +this is what she's being sent home on + + + align:start position:0% +this is what she's being sent home on +discharge disposition is to the home + + align:start position:0% +discharge disposition is to the home + + + align:start position:0% +discharge disposition is to the home +with some follow-up service and she's + + align:start position:0% +with some follow-up service and she's + + + align:start position:0% +with some follow-up service and she's +going home and the discharge diagnosis + + align:start position:0% +going home and the discharge diagnosis + + + align:start position:0% +going home and the discharge diagnosis +is infected left femoral popliteal + + align:start position:0% +is infected left femoral popliteal + + + align:start position:0% +is infected left femoral popliteal +bypass graft and the condition and these + + align:start position:0% +bypass graft and the condition and these + + + align:start position:0% +bypass graft and the condition and these +are the instructions to the patient that + + align:start position:0% +are the instructions to the patient that + + + align:start position:0% +are the instructions to the patient that +say you know here's what you can do + + align:start position:0% +say you know here's what you can do + + + align:start position:0% +say you know here's what you can do +here's when you should come back and + + align:start position:0% +here's when you should come back and + + + align:start position:0% +here's when you should come back and +tell us if something is going + + align:start position:0% +tell us if something is going + + + align:start position:0% +tell us if something is going +etc and here's what you should report if + + align:start position:0% +etc and here's what you should report if + + + align:start position:0% +etc and here's what you should report if +if it happens you know if you have + + align:start position:0% +if it happens you know if you have + + + align:start position:0% +if it happens you know if you have +sudden severe bleeding or swelling do + + align:start position:0% +sudden severe bleeding or swelling do + + + align:start position:0% +sudden severe bleeding or swelling do +this follow up with doctor or somebody + + align:start position:0% +this follow up with doctor or somebody + + + align:start position:0% +this follow up with doctor or somebody +or other call his clinic at this number + + align:start position:0% +or other call his clinic at this number + + + align:start position:0% +or other call his clinic at this number +to schedule an appointment and and then + + align:start position:0% +to schedule an appointment and and then + + + align:start position:0% +to schedule an appointment and and then +follow up with doctor somebody else in + + align:start position:0% +follow up with doctor somebody else in + + + align:start position:0% +follow up with doctor somebody else in +two weeks I think this is the same one + + align:start position:0% +two weeks I think this is the same one + + + align:start position:0% +two weeks I think this is the same one +so just a couple of final words about + + align:start position:0% +so just a couple of final words about + + + align:start position:0% +so just a couple of final words about +standards so you saw in David's + + align:start position:0% +standards so you saw in David's + + + align:start position:0% +standards so you saw in David's +introductory lecture a reference to + + align:start position:0% +introductory lecture a reference to + + + align:start position:0% +introductory lecture a reference to +Odyssey which is a standard method of + + align:start position:0% +Odyssey which is a standard method of + + + align:start position:0% +Odyssey which is a standard method of +encoding the kind of data that we're + + align:start position:0% +encoding the kind of data that we're + + + align:start position:0% +encoding the kind of data that we're +talking about today there's a likelihood + + align:start position:0% +talking about today there's a likelihood + + + align:start position:0% +talking about today there's a likelihood +that the next release of the mimic + + align:start position:0% +that the next release of the mimic + + + align:start position:0% +that the next release of the mimic +database will adopt the Odyssey formats + + align:start position:0% +database will adopt the Odyssey formats + + + align:start position:0% +database will adopt the Odyssey formats +rather than the David shaking his head + + align:start position:0% +rather than the David shaking his head + + + align:start position:0% +rather than the David shaking his head +wondering why me too + + align:start position:0% + + + + align:start position:0% + +well so you know what always happens as + + align:start position:0% +well so you know what always happens as + + + align:start position:0% +well so you know what always happens as +you say I'm going to adopt the standard + + align:start position:0% +you say I'm going to adopt the standard + + + align:start position:0% +you say I'm going to adopt the standard +asterisk with the following extensions + + align:start position:0% +asterisk with the following extensions + + + align:start position:0% +asterisk with the following extensions +and that's probably what's going to + + align:start position:0% +and that's probably what's going to + + + align:start position:0% +and that's probably what's going to +happen but it means that the the central + + align:start position:0% +happen but it means that the the central + + + align:start position:0% +happen but it means that the the central +tables you know the icd-9 code tables + + align:start position:0% +tables you know the icd-9 code tables + + + align:start position:0% +tables you know the icd-9 code tables +and the drug tables and things like that + + align:start position:0% +and the drug tables and things like that + + + align:start position:0% +and the drug tables and things like that +are likely to wind up adopting the + + align:start position:0% +are likely to wind up adopting the + + + align:start position:0% +are likely to wind up adopting the +format's of the Odyssey database you + + align:start position:0% +format's of the Odyssey database you + + + align:start position:0% +format's of the Odyssey database you +should also know about this thing called + + align:start position:0% +should also know about this thing called + + + align:start position:0% +should also know about this thing called +fire fhir the fast health + + align:start position:0% +fire fhir the fast health + + + align:start position:0% +fire fhir the fast health +interoperability resources so hl7 is the + + align:start position:0% +interoperability resources so hl7 is the + + + align:start position:0% +interoperability resources so hl7 is the +standards organization that had a + + align:start position:0% +standards organization that had a + + + align:start position:0% +standards organization that had a +tremendous success in the early 1990s in + + align:start position:0% +tremendous success in the early 1990s in + + + align:start position:0% +tremendous success in the early 1990s in +solving the problem of how to allow + + align:start position:0% +solving the problem of how to allow + + + align:start position:0% +solving the problem of how to allow +laboratories to report lab data back to + + align:start position:0% +laboratories to report lab data back to + + + align:start position:0% +laboratories to report lab data back to +the hospitals or the clinics that + + align:start position:0% +the hospitals or the clinics that + + + align:start position:0% +the hospitals or the clinics that +ordered the labs and that character + + align:start position:0% +ordered the labs and that character + + + align:start position:0% +ordered the labs and that character +string with the up arrows on the + + align:start position:0% +string with the up arrows on the + + + align:start position:0% +string with the up arrows on the +vertical bars and so on that I showed + + align:start position:0% +vertical bars and so on that I showed + + + align:start position:0% +vertical bars and so on that I showed +you before that had link encoded in it + + align:start position:0% +you before that had link encoded in it + + + align:start position:0% +you before that had link encoded in it +is that standard that's called hl7 + + align:start position:0% +is that standard that's called hl7 + + + align:start position:0% +is that standard that's called hl7 +version 2 it's still in use very widely + + align:start position:0% +version 2 it's still in use very widely + + + align:start position:0% +version 2 it's still in use very widely +they then got ambitious and suffered + + align:start position:0% +they then got ambitious and suffered + + + align:start position:0% +they then got ambitious and suffered +second system syndrome which is they + + align:start position:0% +second system syndrome which is they + + + align:start position:0% +second system syndrome which is they +decided to build hl7 version 3 which I + + align:start position:0% +decided to build hl7 version 3 which I + + + align:start position:0% +decided to build hl7 version 3 which I +used to teach in a class here 10 years + + align:start position:0% +used to teach in a class here 10 years + + + align:start position:0% +used to teach in a class here 10 years +ago but one of my friends who works for + + align:start position:0% +ago but one of my friends who works for + + + align:start position:0% +ago but one of my friends who works for +a company that helps hospitals implement + + align:start position:0% +a company that helps hospitals implement + + + align:start position:0% +a company that helps hospitals implement +that sent me a like a 38 megabyte PDF + + align:start position:0% +that sent me a like a 38 megabyte PDF + + + align:start position:0% +that sent me a like a 38 megabyte PDF +file that describes what you need to + + align:start position:0% +file that describes what you need to + + + align:start position:0% +file that describes what you need to +know in order to implement that system + + align:start position:0% +know in order to implement that system + + + align:start position:0% +know in order to implement that system +and as a result nobody was doing it so + + align:start position:0% +and as a result nobody was doing it so + + + align:start position:0% +and as a result nobody was doing it so +fire is a gross simplification of that + + align:start position:0% +fire is a gross simplification of that + + + align:start position:0% +fire is a gross simplification of that +that starts off and says if a doctor + + align:start position:0% +that starts off and says if a doctor + + + align:start position:0% +that starts off and says if a doctor +refers a new patient to you what is the + + align:start position:0% +refers a new patient to you what is the + + + align:start position:0% +refers a new patient to you what is the +minimum set of data that you need to + + align:start position:0% +minimum set of data that you need to + + + align:start position:0% +minimum set of data that you need to +know in order to take care of that + + align:start position:0% +know in order to take care of that + + + align:start position:0% +know in order to take care of that +person and fire tries to provide just + + align:start position:0% +person and fire tries to provide just + + + align:start position:0% +person and fire tries to provide just +that subset of all the data it has + + align:start position:0% +that subset of all the data it has + + + align:start position:0% +that subset of all the data it has +become a standard mainly because after + + align:start position:0% +become a standard mainly because after + + + align:start position:0% +become a standard mainly because after +Congress spent 42 billion dollars or so + + align:start position:0% +Congress spent 42 billion dollars or so + + + align:start position:0% +Congress spent 42 billion dollars or so +bribing people into buying these + + align:start position:0% +bribing people into buying these + + + align:start position:0% +bribing people into buying these +informations + + align:start position:0% +informations + + + align:start position:0% +informations +they got mad that the information + + align:start position:0% +they got mad that the information + + + align:start position:0% +they got mad that the information +systems they bought couldn't talk to + + align:start position:0% +systems they bought couldn't talk to + + + align:start position:0% +systems they bought couldn't talk to +each other and so they called in on the + + align:start position:0% +each other and so they called in on the + + + align:start position:0% +each other and so they called in on the +carpet the heads of these IT companies + + align:start position:0% +carpet the heads of these IT companies + + + align:start position:0% +carpet the heads of these IT companies +health IT companies and they yelled at + + align:start position:0% +health IT companies and they yelled at + + + align:start position:0% +health IT companies and they yelled at +them and they made them promise that + + align:start position:0% +them and they made them promise that + + + align:start position:0% +them and they made them promise that +there would be interoperability they + + align:start position:0% +there would be interoperability they + + + align:start position:0% +there would be interoperability they +promised and out of that came fire it + + align:start position:0% +promised and out of that came fire it + + + align:start position:0% +promised and out of that came fire it +was probably simultaneously developed + + align:start position:0% +was probably simultaneously developed + + + align:start position:0% +was probably simultaneously developed +but they adopted it and so now in + + align:start position:0% +but they adopted it and so now in + + + align:start position:0% +but they adopted it and so now in +principle it's possible to exchange data + + align:start position:0% +principle it's possible to exchange data + + + align:start position:0% +principle it's possible to exchange data +between different hospitals at least to + + align:start position:0% +between different hospitals at least to + + + align:start position:0% +between different hospitals at least to +the level of that degree of + + align:start position:0% +the level of that degree of + + + align:start position:0% +the level of that degree of +harmonization of the data in reality the + + align:start position:0% +harmonization of the data in reality the + + + align:start position:0% +harmonization of the data in reality the +companies don't want you to do that + + align:start position:0% +companies don't want you to do that + + + align:start position:0% +companies don't want you to do that +because they like there to be friction + + align:start position:0% +because they like there to be friction + + + align:start position:0% +because they like there to be friction +in not being able to take all your data + + align:start position:0% +in not being able to take all your data + + + align:start position:0% +in not being able to take all your data +to a different Hospital because it is + + align:start position:0% +to a different Hospital because it is + + + align:start position:0% +to a different Hospital because it is +more likely to leave you at the one that + + align:start position:0% +more likely to leave you at the one that + + + align:start position:0% +more likely to leave you at the one that +you're at + + align:start position:0% +you're at + + + align:start position:0% +you're at +so there's complicated socio-economic + + align:start position:0% +so there's complicated socio-economic + + + align:start position:0% +so there's complicated socio-economic +kinds of issues in all this but at least + + align:start position:0% +kinds of issues in all this but at least + + + align:start position:0% +kinds of issues in all this but at least +the standard exists and is becoming more + + align:start position:0% +the standard exists and is becoming more + + + align:start position:0% +the standard exists and is becoming more +and more widely deployed as long as + + align:start position:0% +and more widely deployed as long as + + + align:start position:0% +and more widely deployed as long as +Congress pays attention it's ugly + + align:start position:0% +Congress pays attention it's ugly + + + align:start position:0% +Congress pays attention it's ugly +so here's what a patient looks like + + align:start position:0% +so here's what a patient looks like + + + align:start position:0% +so here's what a patient looks like +right it's the usual unreadable XML + + align:start position:0% +right it's the usual unreadable XML + + + align:start position:0% +right it's the usual unreadable XML +garbage but fortunately there are + + align:start position:0% +garbage but fortunately there are + + + align:start position:0% +garbage but fortunately there are +parsers that can turn it into JSON and + + align:start position:0% +parsers that can turn it into JSON and + + + align:start position:0% +parsers that can turn it into JSON and +simpler representations and so that + + align:start position:0% +simpler representations and so that + + + align:start position:0% +simpler representations and so that +that's pretty common so the + + align:start position:0% +that's pretty common so the + + + align:start position:0% +that's pretty common so the +terminologies that exist or loin and NDC + + align:start position:0% +terminologies that exist or loin and NDC + + + align:start position:0% +terminologies that exist or loin and NDC +ICD 9 and 10 sno-med I didn't talk about + + align:start position:0% +ICD 9 and 10 sno-med I didn't talk about + + + align:start position:0% +ICD 9 and 10 sno-med I didn't talk about +today dsm-5 is the Diagnostic and + + align:start position:0% +today dsm-5 is the Diagnostic and + + + align:start position:0% +today dsm-5 is the Diagnostic and +Statistical Manual for psychiatrists + + align:start position:0% +Statistical Manual for psychiatrists + + + align:start position:0% +Statistical Manual for psychiatrists +that's used as a common coding method + + align:start position:0% +that's used as a common coding method + + + align:start position:0% +that's used as a common coding method +for psyche describing psychiatric + + align:start position:0% +for psyche describing psychiatric + + + align:start position:0% +for psyche describing psychiatric +disease and there are many more of these + + align:start position:0% +disease and there are many more of these + + + align:start position:0% +disease and there are many more of these +there's something called the unified + + align:start position:0% +there's something called the unified + + + align:start position:0% +there's something called the unified +medical language systems metaphor Saurus + + align:start position:0% +medical language systems metaphor Saurus + + + align:start position:0% +medical language systems metaphor Saurus +from the National Library of Medicine + + align:start position:0% +from the National Library of Medicine + + + align:start position:0% +from the National Library of Medicine +that integrates about a hundred and + + align:start position:0% +that integrates about a hundred and + + + align:start position:0% +that integrates about a hundred and +eighty of these different terminologies + + align:start position:0% +eighty of these different terminologies + + + align:start position:0% +eighty of these different terminologies +and so there is a nice once one-stop + + align:start position:0% +and so there is a nice once one-stop + + + align:start position:0% +and so there is a nice once one-stop +shop where you can get all these things + + align:start position:0% +shop where you can get all these things + + + align:start position:0% +shop where you can get all these things +from them + + align:start position:0% + + + + align:start position:0% + +so takeaway lessons know your data + + align:start position:0% +so takeaway lessons know your data + + + align:start position:0% +so takeaway lessons know your data +remember that first example of the heart + + align:start position:0% +remember that first example of the heart + + + align:start position:0% +remember that first example of the heart +rates that comes up over and over again + + align:start position:0% +rates that comes up over and over again + + + align:start position:0% +rates that comes up over and over again +and doing machine learning and analysis + + align:start position:0% +and doing machine learning and analysis + + + align:start position:0% +and doing machine learning and analysis +on data that you don't understand is + + align:start position:0% +on data that you don't understand is + + + align:start position:0% +on data that you don't understand is +likely to lead you to false conclusions + + align:start position:0% + + + + align:start position:0% + +harmonization is difficult and + + align:start position:0% +harmonization is difficult and + + + align:start position:0% +harmonization is difficult and +time-consuming and there are lots of + + align:start position:0% +time-consuming and there are lots of + + + align:start position:0% +time-consuming and there are lots of +things for which we just don't have + + align:start position:0% +things for which we just don't have + + + align:start position:0% +things for which we just don't have +standards and so everybody develops + + align:start position:0% +standards and so everybody develops + + + align:start position:0% +standards and so everybody develops +their own representations I had a PhD + + align:start position:0% +their own representations I had a PhD + + + align:start position:0% +their own representations I had a PhD +student about a decade ago who in his + + align:start position:0% +student about a decade ago who in his + + + align:start position:0% +student about a decade ago who in his +thesis wrote that he spent about half + + align:start position:0% +thesis wrote that he spent about half + + + align:start position:0% +thesis wrote that he spent about half +his time cleaning data and I gave that + + align:start position:0% +his time cleaning data and I gave that + + + align:start position:0% +his time cleaning data and I gave that +thesis to another student who started a + + align:start position:0% +thesis to another student who started a + + + align:start position:0% +thesis to another student who started a +few years later who read it and he comes + + align:start position:0% +few years later who read it and he comes + + + align:start position:0% +few years later who read it and he comes +to me with just awestruck and he says + + align:start position:0% +to me with just awestruck and he says + + + align:start position:0% +to me with just awestruck and he says +what he only spent half his time clean + + align:start position:0% + + + + align:start position:0% + +unfortunately that's roughly where we + + align:start position:0% +unfortunately that's roughly where we + + + align:start position:0% +unfortunately that's roughly where we +are in this field so sorry to be a + + align:start position:0% +are in this field so sorry to be a + + + align:start position:0% +are in this field so sorry to be a +downer but that's that's the current + + align:start position:0% +downer but that's that's the current + + + align:start position:0% +downer but that's that's the current +state of the art and next time David + + align:start position:0% +state of the art and next time David + + + align:start position:0% +state of the art and next time David +will start by looking at actually + + align:start position:0% +will start by looking at actually + + + align:start position:0% +will start by looking at actually +building some models with these kinds of + + align:start position:0% +building some models with these kinds of + + + align:start position:0% +building some models with these kinds of +data and showing you what what we can + + align:start position:0% +data and showing you what what we can + + + align:start position:0% +data and showing you what what we can +accomplish all right thank you + + align:start position:0% +accomplish all right thank you + + + align:start position:0% +accomplish all right thank you +you + + align:start position:0% +you + + + align:start position:0% +you +[Applause] + + align:start position:0% + + + + align:start position:0% + +you \ No newline at end of file diff --git a/16Vhe_1b974.txt b/16Vhe_1b974.txt new file mode 100644 index 0000000000000000000000000000000000000000..3cb7a32fb49f9c84087cf9ee9a6cb2400ba13c25 --- /dev/null +++ b/16Vhe_1b974.txt @@ -0,0 +1,3635 @@ +align:start position:0% + +in this video we'll look at a beautiful + + align:start position:0% +in this video we'll look at a beautiful + + + align:start position:0% +in this video we'll look at a beautiful +result that provides us with the + + align:start position:0% +result that provides us with the + + + align:start position:0% +result that provides us with the +existence of graphs with high girth and + + align:start position:0% +existence of graphs with high girth and + + + align:start position:0% +existence of graphs with high girth and +high chromatic number and it's a very + + align:start position:0% +high chromatic number and it's a very + + + align:start position:0% +high chromatic number and it's a very +nice demonstration of the power of the + + align:start position:0% +nice demonstration of the power of the + + + align:start position:0% +nice demonstration of the power of the +probabilistic + + align:start position:0% +probabilistic + + + align:start position:0% +probabilistic +method we'll recall some definitions + + align:start position:0% +method we'll recall some definitions + + + align:start position:0% +method we'll recall some definitions +given a graph G its chromatic number is + + align:start position:0% +given a graph G its chromatic number is + + + align:start position:0% +given a graph G its chromatic number is +the minimum number of colors we need to + + align:start position:0% +the minimum number of colors we need to + + + align:start position:0% +the minimum number of colors we need to +color the vertices of the graph G so + + align:start position:0% +color the vertices of the graph G so + + + align:start position:0% +color the vertices of the graph G so +that no Edge has both end points + + align:start position:0% +that no Edge has both end points + + + align:start position:0% +that no Edge has both end points +receiving the same + + align:start position:0% +receiving the same + + + align:start position:0% +receiving the same +color the girth of a graph G is the + + align:start position:0% +color the girth of a graph G is the + + + align:start position:0% +color the girth of a graph G is the +length of the shortest cycle for example + + align:start position:0% +length of the shortest cycle for example + + + align:start position:0% +length of the shortest cycle for example +the following + + align:start position:0% + + + + align:start position:0% + +graph has scur + + align:start position:0% + + + + align:start position:0% + +four because the shortest cycle in this + + align:start position:0% +four because the shortest cycle in this + + + align:start position:0% +four because the shortest cycle in this +graph has length form and there are a + + align:start position:0% +graph has length form and there are a + + + align:start position:0% +graph has length form and there are a +couple of + + align:start position:0% +couple of + + + align:start position:0% +couple of +them another + + align:start position:0% + + + + align:start position:0% + +example is this graph + + align:start position:0% +example is this graph + + + align:start position:0% +example is this graph +here there are many cycles but the + + align:start position:0% +here there are many cycles but the + + + align:start position:0% +here there are many cycles but the +shortest one has length three it is this + + align:start position:0% +shortest one has length three it is this + + + align:start position:0% +shortest one has length three it is this +triangle up here so the girth is + + align:start position:0% +triangle up here so the girth is + + + align:start position:0% +triangle up here so the girth is +three if the graph is a + + align:start position:0% + + + + align:start position:0% + +tree then he has no cycles in which case + + align:start position:0% +tree then he has no cycles in which case + + + align:start position:0% +tree then he has no cycles in which case +we say that its girth is infinite + + align:start position:0% + + + + align:start position:0% + +okay so what can we say about girth and + + align:start position:0% +okay so what can we say about girth and + + + align:start position:0% +okay so what can we say about girth and +chromatic number + + align:start position:0% +chromatic number + + + align:start position:0% +chromatic number +well suppose your graph contains a + + align:start position:0% +well suppose your graph contains a + + + align:start position:0% +well suppose your graph contains a +click on K + + align:start position:0% + + + + align:start position:0% + +vertices then just to color this click + + align:start position:0% +vertices then just to color this click + + + align:start position:0% +vertices then just to color this click +we need at least K different colors so + + align:start position:0% +we need at least K different colors so + + + align:start position:0% +we need at least K different colors so +then the chromatic number + + align:start position:0% + + + + align:start position:0% + +is at least + + align:start position:0% + + + + align:start position:0% + +K can we say something in the reverse + + align:start position:0% +K can we say something in the reverse + + + align:start position:0% +K can we say something in the reverse +Direction suppose we have a graph with + + align:start position:0% +Direction suppose we have a graph with + + + align:start position:0% +Direction suppose we have a graph with +high chromatic + + align:start position:0% + + + + align:start position:0% + +number would it be possible to deduce + + align:start position:0% +number would it be possible to deduce + + + align:start position:0% +number would it be possible to deduce +some local information + + align:start position:0% + + + + align:start position:0% + +about the graph for example would it be + + align:start position:0% +about the graph for example would it be + + + align:start position:0% +about the graph for example would it be +possible to say that if we have very + + align:start position:0% +possible to say that if we have very + + + align:start position:0% +possible to say that if we have very +high chromatic number then there must be + + align:start position:0% +high chromatic number then there must be + + + align:start position:0% +high chromatic number then there must be +a triangle somewhere in the graph or + + align:start position:0% +a triangle somewhere in the graph or + + + align:start position:0% +a triangle somewhere in the graph or +there's some fairly dense structure + + align:start position:0% +there's some fairly dense structure + + + align:start position:0% +there's some fairly dense structure +that's very local in this + + align:start position:0% +that's very local in this + + + align:start position:0% +that's very local in this +graph so the main theorem that we'll + + align:start position:0% +graph so the main theorem that we'll + + + align:start position:0% +graph so the main theorem that we'll +present in this video gives a definitive + + align:start position:0% +present in this video gives a definitive + + + align:start position:0% +present in this video gives a definitive +no to this question + + align:start position:0% + + + + align:start position:0% + +and it is a classic result due to Paul + + align:start position:0% + + + + align:start position:0% + +erish from the + + align:start position:0% + + + + align:start position:0% + +50s and the statement of theorem is the + + align:start position:0% +50s and the statement of theorem is the + + + align:start position:0% +50s and the statement of theorem is the +following for + + align:start position:0% + + + + align:start position:0% + +any positive integers K and + + align:start position:0% +any positive integers K and + + + align:start position:0% +any positive integers K and +L there exists + + align:start position:0% + + + + align:start position:0% + +a + + align:start position:0% + + + + align:start position:0% + +graph there exists a + + align:start position:0% + + + + align:start position:0% + +graph with + + align:start position:0% +graph with + + + align:start position:0% +graph with +girth + + align:start position:0% +girth + + + align:start position:0% +girth +L girth bigger than L and chromatic + + align:start position:0% +L girth bigger than L and chromatic + + + align:start position:0% +L girth bigger than L and chromatic +number + + align:start position:0% + + + + align:start position:0% + +bigger than + + align:start position:0% + + + + align:start position:0% + +K okay so let's pause for a moment and + + align:start position:0% +K okay so let's pause for a moment and + + + align:start position:0% +K okay so let's pause for a moment and +think about what this theorem is saying + + align:start position:0% +think about what this theorem is saying + + + align:start position:0% +think about what this theorem is saying +so given any K&L no matter how large we + + align:start position:0% +so given any K&L no matter how large we + + + align:start position:0% +so given any K&L no matter how large we +can find a graph there exists a graph + + align:start position:0% +can find a graph there exists a graph + + + align:start position:0% +can find a graph there exists a graph +for which there are no short Cycles no + + align:start position:0% +for which there are no short Cycles no + + + align:start position:0% +for which there are no short Cycles no +cycles of length and most L and + + align:start position:0% +cycles of length and most L and + + + align:start position:0% +cycles of length and most L and +furthermore to properly color the + + align:start position:0% +furthermore to properly color the + + + align:start position:0% +furthermore to properly color the +vertices of the graph you need at least + + align:start position:0% +vertices of the graph you need at least + + + align:start position:0% +vertices of the graph you need at least +you need strictly more than K colors + + align:start position:0% +you need strictly more than K colors + + + align:start position:0% +you need strictly more than K colors +so even though this graph has very high + + align:start position:0% +so even though this graph has very high + + + align:start position:0% +so even though this graph has very high +chromatic number around every vertex if + + align:start position:0% +chromatic number around every vertex if + + + align:start position:0% +chromatic number around every vertex if +you only look not too far away then the + + align:start position:0% +you only look not too far away then the + + + align:start position:0% +you only look not too far away then the +graph locally looks like a tree because + + align:start position:0% +graph locally looks like a tree because + + + align:start position:0% +graph locally looks like a tree because +there are no short + + align:start position:0% +there are no short + + + align:start position:0% +there are no short +Cycles so in particular having high + + align:start position:0% +Cycles so in particular having high + + + align:start position:0% +Cycles so in particular having high +chromatic number does not give you local + + align:start position:0% +chromatic number does not give you local + + + align:start position:0% +chromatic number does not give you local +information and eror shows that there + + align:start position:0% +information and eror shows that there + + + align:start position:0% +information and eror shows that there +always + + align:start position:0% +always + + + align:start position:0% +always +exists counter examples to such a + + align:start position:0% +exists counter examples to such a + + + align:start position:0% +exists counter examples to such a +statement if we want some local + + align:start position:0% +statement if we want some local + + + align:start position:0% +statement if we want some local +information from High chromatic + + align:start position:0% +information from High chromatic + + + align:start position:0% +information from High chromatic +number okay so the rest of this video + + align:start position:0% +number okay so the rest of this video + + + align:start position:0% +number okay so the rest of this video +will concern the proof of ERS + + align:start position:0% +will concern the proof of ERS + + + align:start position:0% +will concern the proof of ERS +theorem it's quite a miraculous result + + align:start position:0% +theorem it's quite a miraculous result + + + align:start position:0% +theorem it's quite a miraculous result +and certainly before ERS proved this + + align:start position:0% +and certainly before ERS proved this + + + align:start position:0% +and certainly before ERS proved this +result there were other resulting graph + + align:start position:0% +result there were other resulting graph + + + align:start position:0% +result there were other resulting graph +theory that constructed very explicit + + align:start position:0% +theory that constructed very explicit + + + align:start position:0% +theory that constructed very explicit +graphs that have some large chromatic + + align:start position:0% +graphs that have some large chromatic + + + align:start position:0% +graphs that have some large chromatic +number and girth but not for all values + + align:start position:0% +number and girth but not for all values + + + align:start position:0% +number and girth but not for all values +of K and those constructions are in some + + align:start position:0% +of K and those constructions are in some + + + align:start position:0% +of K and those constructions are in some +sense very Hands-On it tells you how + + align:start position:0% +sense very Hands-On it tells you how + + + align:start position:0% +sense very Hands-On it tells you how +exactly how to construct these graphs + + align:start position:0% +exactly how to construct these graphs + + + align:start position:0% +exactly how to construct these graphs +but they were not able to get + + align:start position:0% +but they were not able to get + + + align:start position:0% +but they were not able to get +arbitrarily large girth and chromatic + + align:start position:0% +arbitrarily large girth and chromatic + + + align:start position:0% +arbitrarily large girth and chromatic +number A's Insight is to use Randomness + + align:start position:0% +number A's Insight is to use Randomness + + + align:start position:0% +number A's Insight is to use Randomness +use the probabilistic method and show + + align:start position:0% +use the probabilistic method and show + + + align:start position:0% +use the probabilistic method and show +that by appropriately modifying a random + + align:start position:0% +that by appropriately modifying a random + + + align:start position:0% +that by appropriately modifying a random +graph one can achieve the desired + + align:start position:0% +graph one can achieve the desired + + + align:start position:0% +graph one can achieve the desired +outcome so let's see how this works + + align:start position:0% + + + + align:start position:0% + +we'll Begin by taking an random graph + + align:start position:0% +we'll Begin by taking an random graph + + + align:start position:0% +we'll Begin by taking an random graph +GNP so this is the a + + align:start position:0% + + + + align:start position:0% + +r random + + align:start position:0% + + + + align:start position:0% + +graph + + align:start position:0% +graph + + + align:start position:0% +graph +and there nend vertices + + align:start position:0% + + + + align:start position:0% + +and um The Edge probability is + + align:start position:0% + + + + align:start position:0% + +p meaning that we flip a probability P + + align:start position:0% +p meaning that we flip a probability P + + + align:start position:0% +p meaning that we flip a probability P +coin for each possible Edge and put down + + align:start position:0% +coin for each possible Edge and put down + + + align:start position:0% +coin for each possible Edge and put down +an edge + + align:start position:0% +an edge + + + align:start position:0% +an edge +independently with probability P between + + align:start position:0% +independently with probability P between + + + align:start position:0% +independently with probability P between +every pair of + + align:start position:0% +every pair of + + + align:start position:0% +every pair of +vertices + + align:start position:0% + + + + align:start position:0% + +right so let G be drawn from this + + align:start position:0% +right so let G be drawn from this + + + align:start position:0% +right so let G be drawn from this +distribution so G is this random + + align:start position:0% + + + + align:start position:0% + +graph now + + align:start position:0% +graph now + + + align:start position:0% +graph now +let's take a specific choice of + + align:start position:0% + + + + align:start position:0% + +P being log n^ s Over N turns out other + + align:start position:0% +P being log n^ s Over N turns out other + + + align:start position:0% +P being log n^ s Over N turns out other +choices of P work as long as P Falls in + + align:start position:0% +choices of P work as long as P Falls in + + + align:start position:0% +choices of P work as long as P Falls in +some range but for concreteness we'll + + align:start position:0% +some range but for concreteness we'll + + + align:start position:0% +some range but for concreteness we'll +take this very specific choice of P so + + align:start position:0% +take this very specific choice of P so + + + align:start position:0% +take this very specific choice of P so +this is a random graph and let's + + align:start position:0% +this is a random graph and let's + + + align:start position:0% +this is a random graph and let's +construct the random variable + + align:start position:0% + + + + align:start position:0% + +X defined to be the number of + + align:start position:0% +X defined to be the number of + + + align:start position:0% +X defined to be the number of +cycles of + + align:start position:0% + + + + align:start position:0% + +length at most + + align:start position:0% +length at most + + + align:start position:0% +length at most +l in G okay so these are short Cycles in + + align:start position:0% +l in G okay so these are short Cycles in + + + align:start position:0% +l in G okay so these are short Cycles in +G and these are the cycles that we want + + align:start position:0% +G and these are the cycles that we want + + + align:start position:0% +G and these are the cycles that we want +to avoid because we want to construct a + + align:start position:0% +to avoid because we want to construct a + + + align:start position:0% +to avoid because we want to construct a +graph with girth strictly larger than l + + align:start position:0% +graph with girth strictly larger than l + + + align:start position:0% +graph with girth strictly larger than l +so we really do not like these + + align:start position:0% +so we really do not like these + + + align:start position:0% +so we really do not like these +Cycles it will be nice if there were not + + align:start position:0% +Cycles it will be nice if there were not + + + align:start position:0% +Cycles it will be nice if there were not +too many such Cycles so let's compute + + align:start position:0% +too many such Cycles so let's compute + + + align:start position:0% +too many such Cycles so let's compute +the expected value of + + align:start position:0% +the expected value of + + + align:start position:0% +the expected value of +x for this computation we use linearity + + align:start position:0% +x for this computation we use linearity + + + align:start position:0% +x for this computation we use linearity +of + + align:start position:0% +of + + + align:start position:0% +of +expectations and look over all possible + + align:start position:0% +expectations and look over all possible + + + align:start position:0% +expectations and look over all possible +cycle lengths from 3 to + + align:start position:0% +cycle lengths from 3 to + + + align:start position:0% +cycle lengths from 3 to +L right so I is the target cycle length + + align:start position:0% +L right so I is the target cycle length + + + align:start position:0% +L right so I is the target cycle length +and for cycles of length + + align:start position:0% +and for cycles of length + + + align:start position:0% +and for cycles of length +I there are n choose I different choices + + align:start position:0% +I there are n choose I different choices + + + align:start position:0% +I there are n choose I different choices +of + + align:start position:0% +of + + + align:start position:0% +of +which I vertices the Cycles can + + align:start position:0% +which I vertices the Cycles can + + + align:start position:0% +which I vertices the Cycles can +involve and once you specify those + + align:start position:0% +involve and once you specify those + + + align:start position:0% +involve and once you specify those +vertices there are IUS one factorial + + align:start position:0% +vertices there are IUS one factorial + + + align:start position:0% +vertices there are IUS one factorial +different permutations circular + + align:start position:0% +different permutations circular + + + align:start position:0% +different permutations circular +permutations of these vertices and we + + align:start position:0% +permutations of these vertices and we + + + align:start position:0% +permutations of these vertices and we +divide it by two + + align:start position:0% +divide it by two + + + align:start position:0% +divide it by two +because a cycle could be counted in two + + align:start position:0% +because a cycle could be counted in two + + + align:start position:0% +because a cycle could be counted in two +different directions and they will + + align:start position:0% +different directions and they will + + + align:start position:0% +different directions and they will +correspond to the same + + align:start position:0% +correspond to the same + + + align:start position:0% +correspond to the same +cycle so + + align:start position:0% +cycle so + + + align:start position:0% +cycle so +so this quantity here is the number of + + align:start position:0% +so this quantity here is the number of + + + align:start position:0% +so this quantity here is the number of +cycles of + + align:start position:0% +cycles of + + + align:start position:0% +cycles of +length I in the complete graph on N + + align:start position:0% +length I in the complete graph on N + + + align:start position:0% +length I in the complete graph on N +vertices with all edges + + align:start position:0% +vertices with all edges + + + align:start position:0% +vertices with all edges +present for each such possible cycle the + + align:start position:0% +present for each such possible cycle the + + + align:start position:0% +present for each such possible cycle the +probability that the cycle appears in G + + align:start position:0% +probability that the cycle appears in G + + + align:start position:0% +probability that the cycle appears in G +is p to the I so the second term + + align:start position:0% +is p to the I so the second term + + + align:start position:0% +is p to the I so the second term +here is probability + + align:start position:0% +here is probability + + + align:start position:0% +here is probability +that + + align:start position:0% +that + + + align:start position:0% +that +this + + align:start position:0% +this + + + align:start position:0% +this +cycle + + align:start position:0% + + + + align:start position:0% + +appears in + + align:start position:0% + + + + align:start position:0% + +GMP okay this is some expression it's a + + align:start position:0% +GMP okay this is some expression it's a + + + align:start position:0% +GMP okay this is some expression it's a +little complicated but we can simplify + + align:start position:0% +little complicated but we can simplify + + + align:start position:0% +little complicated but we can simplify +it and do some approximations to Upper + + align:start position:0% +it and do some approximations to Upper + + + align:start position:0% +it and do some approximations to Upper +bound this + + align:start position:0% +bound this + + + align:start position:0% +bound this +quantity so you see that the + + align:start position:0% +quantity so you see that the + + + align:start position:0% +quantity so you see that the +um n choose I if you expand it in terms + + align:start position:0% +um n choose I if you expand it in terms + + + align:start position:0% +um n choose I if you expand it in terms +of + + align:start position:0% +of + + + align:start position:0% +of +factorials one can upper bound this + + align:start position:0% +factorials one can upper bound this + + + align:start position:0% +factorials one can upper bound this +quantity by n to the I so incorporating + + align:start position:0% +quantity by n to the I so incorporating + + + align:start position:0% +quantity by n to the I so incorporating +the um the first two + + align:start position:0% +the um the first two + + + align:start position:0% +the um the first two +factors and then leaving P to the I + + align:start position:0% +factors and then leaving P to the I + + + align:start position:0% +factors and then leaving P to the I +factor + + align:start position:0% + + + + align:start position:0% + +intact + + align:start position:0% +intact + + + align:start position:0% +intact +okay we chose P so that P * n equals to + + align:start position:0% +okay we chose P so that P * n equals to + + + align:start position:0% +okay we chose P so that P * n equals to +log s of M and + + align:start position:0% + + + + align:start position:0% + +so we can rewrite this quantity + + align:start position:0% + + + + align:start position:0% + +here like + + align:start position:0% + + + + align:start position:0% + +this okay uh there are L terms here so + + align:start position:0% +this okay uh there are L terms here so + + + align:start position:0% +this okay uh there are L terms here so +let + + align:start position:0% + + + + align:start position:0% + +me furthermore upper bound this + + align:start position:0% +me furthermore upper bound this + + + align:start position:0% +me furthermore upper bound this +expression by L Times log n to + + align:start position:0% +expression by L Times log n to + + + align:start position:0% +expression by L Times log n to +the 2 L here L is a constant so this + + align:start position:0% +the 2 L here L is a constant so this + + + align:start position:0% +the 2 L here L is a constant so this +quantity here is some growth and the + + align:start position:0% +quantity here is some growth and the + + + align:start position:0% +quantity here is some growth and the +rate of some power of a log and + + align:start position:0% +rate of some power of a log and + + + align:start position:0% +rate of some power of a log and +certainly + + align:start position:0% +certainly + + + align:start position:0% +certainly +much slower growing compared to the + + align:start position:0% +much slower growing compared to the + + + align:start position:0% +much slower growing compared to the +function n so it's little o of n okay + + align:start position:0% +function n so it's little o of n okay + + + align:start position:0% +function n so it's little o of n okay +it's a fairly crude approximation but + + align:start position:0% +it's a fairly crude approximation but + + + align:start position:0% +it's a fairly crude approximation but +will be sufficient for our + + align:start position:0% +will be sufficient for our + + + align:start position:0% +will be sufficient for our +purposes so this is a calculation + + align:start position:0% +purposes so this is a calculation + + + align:start position:0% +purposes so this is a calculation +conclusion can be read as the expected + + align:start position:0% +conclusion can be read as the expected + + + align:start position:0% +conclusion can be read as the expected +number of short Cycles is fairly + + align:start position:0% +number of short Cycles is fairly + + + align:start position:0% +number of short Cycles is fairly +small well if there are few short Cycles + + align:start position:0% +small well if there are few short Cycles + + + align:start position:0% +small well if there are few short Cycles +we + + align:start position:0% +we + + + align:start position:0% +we +can get rid of all of them to get a + + align:start position:0% +can get rid of all of them to get a + + + align:start position:0% +can get rid of all of them to get a +graph without short Cycles so this is + + align:start position:0% +graph without short Cycles so this is + + + align:start position:0% +graph without short Cycles so this is +the basic idea of the alteration method + + align:start position:0% +the basic idea of the alteration method + + + align:start position:0% +the basic idea of the alteration method +in the probabilistic method okay so + + align:start position:0% +in the probabilistic method okay so + + + align:start position:0% +in the probabilistic method okay so +start with this GMP this random + + align:start position:0% +start with this GMP this random + + + align:start position:0% +start with this GMP this random +graph it's not going to get us what we + + align:start position:0% +graph it's not going to get us what we + + + align:start position:0% +graph it's not going to get us what we +want right away but we're going to do + + align:start position:0% +want right away but we're going to do + + + align:start position:0% +want right away but we're going to do +something to fix the defects in this + + align:start position:0% +something to fix the defects in this + + + align:start position:0% +something to fix the defects in this +graph in this case get rid of short + + align:start position:0% +graph in this case get rid of short + + + align:start position:0% +graph in this case get rid of short +Cycles to that end that is known that by + + align:start position:0% +Cycles to that end that is known that by + + + align:start position:0% +Cycles to that end that is known that by +markov's + + align:start position:0% +markov's + + + align:start position:0% +markov's +inequality the + + align:start position:0% +inequality the + + + align:start position:0% +inequality the +probability that the number of short + + align:start position:0% +probability that the number of short + + + align:start position:0% +probability that the number of short +Cycles here short means length and most + + align:start position:0% +Cycles here short means length and most + + + align:start position:0% +Cycles here short means length and most +L the probability that the number of of + + align:start position:0% +L the probability that the number of of + + + align:start position:0% +L the probability that the number of of +short Cycles X is at least n / two is + + align:start position:0% +short Cycles X is at least n / two is + + + align:start position:0% +short Cycles X is at least n / two is +upper bounded by the expectation of x + + align:start position:0% +upper bounded by the expectation of x + + + align:start position:0% +upper bounded by the expectation of x +divided by n /2 + + align:start position:0% +divided by n /2 + + + align:start position:0% +divided by n /2 +and because expectation of X is little o + + align:start position:0% +and because expectation of X is little o + + + align:start position:0% +and because expectation of X is little o +of n this final quantity is little o of + + align:start position:0% +of n this final quantity is little o of + + + align:start position:0% +of n this final quantity is little o of +one is the case to zero as n goes to + + align:start position:0% + + + + align:start position:0% + +Infinity okay + + align:start position:0% +Infinity okay + + + align:start position:0% +Infinity okay +so this is a good sign right so means + + align:start position:0% +so this is a good sign right so means + + + align:start position:0% +so this is a good sign right so means +that typically the graph does not have + + align:start position:0% +that typically the graph does not have + + + align:start position:0% +that typically the graph does not have +very many short Cycles has fewer than n + + align:start position:0% +very many short Cycles has fewer than n + + + align:start position:0% +very many short Cycles has fewer than n +/ two and then eventually we'll be able + + align:start position:0% +/ two and then eventually we'll be able + + + align:start position:0% +/ two and then eventually we'll be able +to get rid of one Edge from each cycle + + align:start position:0% +to get rid of one Edge from each cycle + + + align:start position:0% +to get rid of one Edge from each cycle +to get us a graph with still fairly + + align:start position:0% +to get us a graph with still fairly + + + align:start position:0% +to get us a graph with still fairly +large number of vertices but there are + + align:start position:0% +large number of vertices but there are + + + align:start position:0% +large number of vertices but there are +no short Cycles left in this after the + + align:start position:0% +no short Cycles left in this after the + + + align:start position:0% +no short Cycles left in this after the +alteration now let's think about + + align:start position:0% +alteration now let's think about + + + align:start position:0% +alteration now let's think about +chromatic number so we want to ensure + + align:start position:0% +chromatic number so we want to ensure + + + align:start position:0% +chromatic number so we want to ensure +that the graph that we end up having has + + align:start position:0% +that the graph that we end up having has + + + align:start position:0% +that the graph that we end up having has +high chromatic + + align:start position:0% +high chromatic + + + align:start position:0% +high chromatic +number to that + + align:start position:0% +number to that + + + align:start position:0% +number to that +end we'll recall the following + + align:start position:0% +end we'll recall the following + + + align:start position:0% +end we'll recall the following +fact if we give you a graph + + align:start position:0% +fact if we give you a graph + + + align:start position:0% +fact if we give you a graph +G then the chromatic number of G so this + + align:start position:0% +G then the chromatic number of G so this + + + align:start position:0% +G then the chromatic number of G so this +is Kai of G so that's the chromatic + + align:start position:0% + + + + align:start position:0% + +number well the chromatic number is the + + align:start position:0% +number well the chromatic number is the + + + align:start position:0% +number well the chromatic number is the +minimum number of colors that one need + + align:start position:0% +minimum number of colors that one need + + + align:start position:0% +minimum number of colors that one need +to color the vertices of the graph so + + align:start position:0% +to color the vertices of the graph so + + + align:start position:0% +to color the vertices of the graph so +that no Edge has the same color on both + + align:start position:0% +that no Edge has the same color on both + + + align:start position:0% +that no Edge has the same color on both +sides in particular every color class + + align:start position:0% +sides in particular every color class + + + align:start position:0% +sides in particular every color class +right so if you look at a single color + + align:start position:0% +right so if you look at a single color + + + align:start position:0% +right so if you look at a single color +like red and look at the vertices + + align:start position:0% +like red and look at the vertices + + + align:start position:0% +like red and look at the vertices +colored by that + + align:start position:0% +colored by that + + + align:start position:0% +colored by that +color these vertices have no edges + + align:start position:0% +color these vertices have no edges + + + align:start position:0% +color these vertices have no edges +directly between them and so they form + + align:start position:0% +directly between them and so they form + + + align:start position:0% +directly between them and so they form +an independent set so each color class + + align:start position:0% +an independent set so each color class + + + align:start position:0% +an independent set so each color class +is an independent set and so the number + + align:start position:0% +is an independent set and so the number + + + align:start position:0% +is an independent set and so the number +of color classes you + + align:start position:0% +of color classes you + + + align:start position:0% +of color classes you +need then should be at least the number + + align:start position:0% +need then should be at least the number + + + align:start position:0% +need then should be at least the number +of vertices divided by the independence + + align:start position:0% +of vertices divided by the independence + + + align:start position:0% +of vertices divided by the independence +number this is the size of the largest + + align:start position:0% +number this is the size of the largest + + + align:start position:0% +number this is the size of the largest +independent set so this Alpha of the + + align:start position:0% +independent set so this Alpha of the + + + align:start position:0% +independent set so this Alpha of the +independence number is the + + align:start position:0% +independence number is the + + + align:start position:0% +independence number is the +size of the + + align:start position:0% +size of the + + + align:start position:0% +size of the +largest independent + + align:start position:0% + + + + align:start position:0% + +set indeed each color class is + + align:start position:0% +set indeed each color class is + + + align:start position:0% +set indeed each color class is +independent set and each independent set + + align:start position:0% +independent set and each independent set + + + align:start position:0% +independent set and each independent set +has size at most Alpha of G and + + align:start position:0% +has size at most Alpha of G and + + + align:start position:0% +has size at most Alpha of G and +therefore the number of colors you need + + align:start position:0% +therefore the number of colors you need + + + align:start position:0% +therefore the number of colors you need +should be at least the number of + + align:start position:0% +should be at least the number of + + + align:start position:0% +should be at least the number of +vertices divided by the independence + + align:start position:0% +vertices divided by the independence + + + align:start position:0% +vertices divided by the independence +number + + align:start position:0% + + + + align:start position:0% + +okay now for + + align:start position:0% +okay now for + + + align:start position:0% +okay now for +every + + align:start position:0% +every + + + align:start position:0% +every +H the probability that the independence + + align:start position:0% +H the probability that the independence + + + align:start position:0% +H the probability that the independence +number so after here see that it makes + + align:start position:0% +number so after here see that it makes + + + align:start position:0% +number so after here see that it makes +sense to think about the independence + + align:start position:0% +sense to think about the independence + + + align:start position:0% +sense to think about the independence +number the probability that Independence + + align:start position:0% +number the probability that Independence + + + align:start position:0% +number the probability that Independence +number is bigger than + + align:start position:0% +number is bigger than + + + align:start position:0% +number is bigger than +H + + align:start position:0% +H + + + align:start position:0% +H +is and most the following so here we'll + + align:start position:0% +is and most the following so here we'll + + + align:start position:0% +is and most the following so here we'll +use Union + + align:start position:0% +use Union + + + align:start position:0% +use Union +sound for + + align:start position:0% +sound for + + + align:start position:0% +sound for +each H vertex subset of which there are + + align:start position:0% +each H vertex subset of which there are + + + align:start position:0% +each H vertex subset of which there are +n choose H such H vertex subsets the + + align:start position:0% +n choose H such H vertex subsets the + + + align:start position:0% +n choose H such H vertex subsets the +probability that those H vertices from + + align:start position:0% +probability that those H vertices from + + + align:start position:0% +probability that those H vertices from +an independent + + align:start position:0% +an independent + + + align:start position:0% +an independent +set is the probability that there are no + + align:start position:0% +set is the probability that there are no + + + align:start position:0% +set is the probability that there are no +edges appearing among these H vertices + + align:start position:0% +edges appearing among these H vertices + + + align:start position:0% +edges appearing among these H vertices +and that's 1 minus P raised to the power + + align:start position:0% +and that's 1 minus P raised to the power + + + align:start position:0% +and that's 1 minus P raised to the power +H choose + + align:start position:0% +H choose + + + align:start position:0% +H choose +two okay so this is some expression and + + align:start position:0% +two okay so this is some expression and + + + align:start position:0% +two okay so this is some expression and +we can do some manipulations to simplify + + align:start position:0% +we can do some manipulations to simplify + + + align:start position:0% +we can do some manipulations to simplify +this + + align:start position:0% +this + + + align:start position:0% +this +expression yielding an upper bound of n + + align:start position:0% +expression yielding an upper bound of n + + + align:start position:0% +expression yielding an upper bound of n +to the H times so the latter expression + + align:start position:0% +to the H times so the latter expression + + + align:start position:0% +to the H times so the latter expression +we can simplify it as so upper bounded + + align:start position:0% +we can simplify it as so upper bounded + + + align:start position:0% +we can simplify it as so upper bounded +by e to the minus + + align:start position:0% +by e to the minus + + + align:start position:0% +by e to the minus +p h h -1 / 2 right so 1 minus + + align:start position:0% +p h h -1 / 2 right so 1 minus + + + align:start position:0% +p h h -1 / 2 right so 1 minus +p + + align:start position:0% +p + + + align:start position:0% +p +is less than e to the minus p + + align:start position:0% + + + + align:start position:0% + +okay simplifying further we see that + + align:start position:0% +okay simplifying further we see that + + + align:start position:0% +okay simplifying further we see that +this expression can be + + align:start position:0% + + + + align:start position:0% + +Rewritten this + + align:start position:0% + + + + align:start position:0% + +way and now let's make a choice for what + + align:start position:0% +way and now let's make a choice for what + + + align:start position:0% +way and now let's make a choice for what +H I want to set so let's set H to be the + + align:start position:0% +H I want to set so let's set H to be the + + + align:start position:0% +H I want to set so let's set H to be the +quantity which for now seems a little + + align:start position:0% +quantity which for now seems a little + + + align:start position:0% +quantity which for now seems a little +mysterious but it turns out to be a + + align:start position:0% +mysterious but it turns out to be a + + + align:start position:0% +mysterious but it turns out to be a +natural thing to set after we see what + + align:start position:0% +natural thing to set after we see what + + + align:start position:0% +natural thing to set after we see what +the calculation looks like so we set H + + align:start position:0% +the calculation looks like so we set H + + + align:start position:0% +the calculation looks like so we set H +to be this quantity three * log n over p + + align:start position:0% +to be this quantity three * log n over p + + + align:start position:0% +to be this quantity three * log n over p +and knowing what P was from earlier uh + + align:start position:0% +and knowing what P was from earlier uh + + + align:start position:0% +and knowing what P was from earlier uh +this quantity is 3 n + + align:start position:0% +this quantity is 3 n + + + align:start position:0% +this quantity is 3 n +over log + + align:start position:0% + + + + align:start position:0% + +n if we set H to be this quantity here + + align:start position:0% +n if we set H to be this quantity here + + + align:start position:0% +n if we set H to be this quantity here +then you see that here in this + + align:start position:0% +then you see that here in this + + + align:start position:0% +then you see that here in this +expression the numerator here um can be + + align:start position:0% +expression the numerator here um can be + + + align:start position:0% +expression the numerator here um can be +simplified and the + + align:start position:0% + + + + align:start position:0% + +result is that this expression de + + align:start position:0% +result is that this expression de + + + align:start position:0% +result is that this expression de +case According to some rate which is n + + align:start position:0% +case According to some rate which is n + + + align:start position:0% +case According to some rate which is n +to something that is a minus + + align:start position:0% +to something that is a minus + + + align:start position:0% +to something that is a minus +constant something on a constant word in + + align:start position:0% + + + + align:start position:0% + +particular it goes to zero as n goes to + + align:start position:0% +particular it goes to zero as n goes to + + + align:start position:0% +particular it goes to zero as n goes to +infinity and that's really the only + + align:start position:0% +infinity and that's really the only + + + align:start position:0% +infinity and that's really the only +thing that we need for uh that we need + + align:start position:0% +thing that we need for uh that we need + + + align:start position:0% +thing that we need for uh that we need +out of this + + align:start position:0% +out of this + + + align:start position:0% +out of this +calculation so if we set H to be of an + + align:start position:0% +calculation so if we set H to be of an + + + align:start position:0% +calculation so if we set H to be of an +appropriate quantity then typically one + + align:start position:0% +appropriate quantity then typically one + + + align:start position:0% +appropriate quantity then typically one +does not have independent sets of size + + align:start position:0% +does not have independent sets of size + + + align:start position:0% +does not have independent sets of size +at least H in the + + align:start position:0% +at least H in the + + + align:start position:0% +at least H in the +graph + + align:start position:0% +graph + + + align:start position:0% +graph +okay so let's regroup so we proved a + + align:start position:0% +okay so let's regroup so we proved a + + + align:start position:0% +okay so let's regroup so we proved a +couple of + + align:start position:0% +couple of + + + align:start position:0% +couple of +things first we show that typically so + + align:start position:0% +things first we show that typically so + + + align:start position:0% +things first we show that typically so +when I say typically I mean with + + align:start position:0% +when I say typically I mean with + + + align:start position:0% +when I say typically I mean with +probability approaching one as Ang goes + + align:start position:0% +probability approaching one as Ang goes + + + align:start position:0% +probability approaching one as Ang goes +to Infinity so typically this graph does + + align:start position:0% +to Infinity so typically this graph does + + + align:start position:0% +to Infinity so typically this graph does +not + + align:start position:0% +not + + + align:start position:0% +not +have short Cycles meaning cycles of + + align:start position:0% +have short Cycles meaning cycles of + + + align:start position:0% +have short Cycles meaning cycles of +length and most L and also typically + + align:start position:0% +length and most L and also typically + + + align:start position:0% +length and most L and also typically +this graph does not have large + + align:start position:0% +this graph does not have large + + + align:start position:0% +this graph does not have large +independent + + align:start position:0% +independent + + + align:start position:0% +independent +sets okay now let us put everything + + align:start position:0% +sets okay now let us put everything + + + align:start position:0% +sets okay now let us put everything +together + + align:start position:0% +together + + + align:start position:0% +together +so by + + align:start position:0% + + + + align:start position:0% + +choosing and sufficiently large + + align:start position:0% + + + + align:start position:0% + +we can + + align:start position:0% +we can + + + align:start position:0% +we can +simultaneously ensure that the + + align:start position:0% + + + + align:start position:0% + +probability that X the number of short + + align:start position:0% +probability that X the number of short + + + align:start position:0% +probability that X the number of short +Cycles exceeds n /2 is strictly less + + align:start position:0% +Cycles exceeds n /2 is strictly less + + + align:start position:0% +Cycles exceeds n /2 is strictly less +than + + align:start position:0% +than + + + align:start position:0% +than +half and the probability that the + + align:start position:0% +half and the probability that the + + + align:start position:0% +half and the probability that the +independence number + + align:start position:0% +independence number + + + align:start position:0% +independence number +exceeds H is also strictly less than + + align:start position:0% +exceeds H is also strictly less than + + + align:start position:0% +exceeds H is also strictly less than +half okay so both of these are quantity + + align:start position:0% +half okay so both of these are quantity + + + align:start position:0% +half okay so both of these are quantity +quantities that decay to zero as n goes + + align:start position:0% +quantities that decay to zero as n goes + + + align:start position:0% +quantities that decay to zero as n goes +to Infinity so by choosing sufficiently + + align:start position:0% +to Infinity so by choosing sufficiently + + + align:start position:0% +to Infinity so by choosing sufficiently +r n we can make sure both probabilities + + align:start position:0% +r n we can make sure both probabilities + + + align:start position:0% +r n we can make sure both probabilities +are strictly less than 1/2 and therefore + + align:start position:0% +are strictly less than 1/2 and therefore + + + align:start position:0% +are strictly less than 1/2 and therefore +there is some possibility that lie + + align:start position:0% +there is some possibility that lie + + + align:start position:0% +there is some possibility that lie +outside both + + align:start position:0% + + + + align:start position:0% + +events thus there + + align:start position:0% + + + + align:start position:0% + +exists a graph + + align:start position:0% +exists a graph + + + align:start position:0% +exists a graph +G + + align:start position:0% +G + + + align:start position:0% +G +with + + align:start position:0% +with + + + align:start position:0% +with +fewer + + align:start position:0% +fewer + + + align:start position:0% +fewer +than n / two + + align:start position:0% +than n / two + + + align:start position:0% +than n / two +cycles of + + align:start position:0% +cycles of + + + align:start position:0% +cycles of +length at most + + align:start position:0% + + + + align:start position:0% + +L + + align:start position:0% +L + + + align:start position:0% +L +and furthermore its independent number + + align:start position:0% +and furthermore its independent number + + + align:start position:0% +and furthermore its independent number +the size of the largest independent set + + align:start position:0% +the size of the largest independent set + + + align:start position:0% +the size of the largest independent set +is at + + align:start position:0% +is at + + + align:start position:0% +is at +most H which we said earlier to be 3n + + align:start position:0% +most H which we said earlier to be 3n + + + align:start position:0% +most H which we said earlier to be 3n +over log + + align:start position:0% +over log + + + align:start position:0% +over log +n okay so we have such a graph G that + + align:start position:0% +n okay so we have such a graph G that + + + align:start position:0% +n okay so we have such a graph G that +has these nice + + align:start position:0% +has these nice + + + align:start position:0% +has these nice +properties well we're looking for a + + align:start position:0% +properties well we're looking for a + + + align:start position:0% +properties well we're looking for a +graph with high girth well here G has + + align:start position:0% +graph with high girth well here G has + + + align:start position:0% +graph with high girth well here G has +not too many short Cycles so we can get + + align:start position:0% +not too many short Cycles so we can get + + + align:start position:0% +not too many short Cycles so we can get +rid of one vertex from each short + + align:start position:0% +rid of one vertex from each short + + + align:start position:0% +rid of one vertex from each short +cycle to remove all the short Cycles so + + align:start position:0% +cycle to remove all the short Cycles so + + + align:start position:0% +cycle to remove all the short Cycles so +remove a + + align:start position:0% + + + + align:start position:0% + +Vertex from each short cycle the each + + align:start position:0% +Vertex from each short cycle the each + + + align:start position:0% +Vertex from each short cycle the each +cycle of + + align:start position:0% +cycle of + + + align:start position:0% +cycle of +length at + + align:start position:0% +length at + + + align:start position:0% +length at +most + + align:start position:0% + + + + align:start position:0% + +l so remove one vertex from each such + + align:start position:0% +l so remove one vertex from each such + + + align:start position:0% +l so remove one vertex from each such +cycle and + + align:start position:0% +cycle and + + + align:start position:0% +cycle and +doing so results in a subgraph g + + align:start position:0% +doing so results in a subgraph g + + + align:start position:0% +doing so results in a subgraph g +Prime and then we know that the girth of + + align:start position:0% +Prime and then we know that the girth of + + + align:start position:0% +Prime and then we know that the girth of +G + + align:start position:0% +G + + + align:start position:0% +G +Prime is strictly larger than L because + + align:start position:0% +Prime is strictly larger than L because + + + align:start position:0% +Prime is strictly larger than L because +we got rid of all the short + + align:start position:0% +we got rid of all the short + + + align:start position:0% +we got rid of all the short +cycles and furthermore the chromatic + + align:start position:0% +cycles and furthermore the chromatic + + + align:start position:0% +cycles and furthermore the chromatic +number of G + + align:start position:0% +number of G + + + align:start position:0% +number of G +Prime is by what we saw earlier at least + + align:start position:0% +Prime is by what we saw earlier at least + + + align:start position:0% +Prime is by what we saw earlier at least +the number of vertices of G Prime + + align:start position:0% +the number of vertices of G Prime + + + align:start position:0% +the number of vertices of G Prime +divided by its independ + + align:start position:0% +divided by its independ + + + align:start position:0% +divided by its independ +number well the number of vertices is at + + align:start position:0% +number well the number of vertices is at + + + align:start position:0% +number well the number of vertices is at +least n / two because we removed at most + + align:start position:0% +least n / two because we removed at most + + + align:start position:0% +least n / two because we removed at most +n /2 vertices from G to obtain G + + align:start position:0% +n /2 vertices from G to obtain G + + + align:start position:0% +n /2 vertices from G to obtain G +Prime the independence number of G Prime + + align:start position:0% +Prime the independence number of G Prime + + + align:start position:0% +Prime the independence number of G Prime +well the independence number of G + + align:start position:0% +well the independence number of G + + + align:start position:0% +well the independence number of G +Prime is at most the independence number + + align:start position:0% +Prime is at most the independence number + + + align:start position:0% +Prime is at most the independence number +of G because any independent set in G + + align:start position:0% +of G because any independent set in G + + + align:start position:0% +of G because any independent set in G +Prime is automatically independent set + + align:start position:0% +Prime is automatically independent set + + + align:start position:0% +Prime is automatically independent set +in G and here we saw that + + align:start position:0% +in G and here we saw that + + + align:start position:0% +in G and here we saw that +the independent number of G Prime is at + + align:start position:0% +the independent number of G Prime is at + + + align:start position:0% +the independent number of G Prime is at +most H which is three log n over 3 n + + align:start position:0% +most H which is three log n over 3 n + + + align:start position:0% +most H which is three log n over 3 n +over log + + align:start position:0% + + + + align:start position:0% + +n so we have in the denominator 3n + + align:start position:0% +n so we have in the denominator 3n + + + align:start position:0% +n so we have in the denominator 3n +over + + align:start position:0% + + + + align:start position:0% + +login + + align:start position:0% +login + + + align:start position:0% +login +and whole expression simplifies to log n + + align:start position:0% +and whole expression simplifies to log n + + + align:start position:0% +and whole expression simplifies to log n +/ 6 + + align:start position:0% +/ 6 + + + align:start position:0% +/ 6 +which is bigger than the constant that + + align:start position:0% +which is bigger than the constant that + + + align:start position:0% +which is bigger than the constant that +we were given K as + + align:start position:0% +we were given K as + + + align:start position:0% +we were given K as +long as n is sufficiently + + align:start position:0% + + + + align:start position:0% + +large + + align:start position:0% +large + + + align:start position:0% +large +and thus G Prime + + align:start position:0% + + + + align:start position:0% + +satisfies the desired + + align:start position:0% + + + + align:start position:0% + +requirements okay this finishes the + + align:start position:0% +requirements okay this finishes the + + + align:start position:0% +requirements okay this finishes the +proof of this theorem of airush that + + align:start position:0% +proof of this theorem of airush that + + + align:start position:0% +proof of this theorem of airush that +there exists graphs with arbitrarily + + align:start position:0% +there exists graphs with arbitrarily + + + align:start position:0% +there exists graphs with arbitrarily +large girth and arbitrarily large + + align:start position:0% +large girth and arbitrarily large + + + align:start position:0% +large girth and arbitrarily large +chromatic + + align:start position:0% +chromatic + + + align:start position:0% +chromatic +number to review some of the key ideas + + align:start position:0% +number to review some of the key ideas + + + align:start position:0% +number to review some of the key ideas +in this proof we use the probabilistic + + align:start position:0% +in this proof we use the probabilistic + + + align:start position:0% +in this proof we use the probabilistic +method with alterations to construct + + align:start position:0% +method with alterations to construct + + + align:start position:0% +method with alterations to construct +first a random + + align:start position:0% +first a random + + + align:start position:0% +first a random +graph with various parameters so that + + align:start position:0% +graph with various parameters so that + + + align:start position:0% +graph with various parameters so that +this random graph typically has very few + + align:start position:0% +this random graph typically has very few + + + align:start position:0% +this random graph typically has very few +short + + align:start position:0% +short + + + align:start position:0% +short +Cycles so that we can then remove one + + align:start position:0% +Cycles so that we can then remove one + + + align:start position:0% +Cycles so that we can then remove one +vertex from each short + + align:start position:0% +vertex from each short + + + align:start position:0% +vertex from each short +cycle and get rid of all the short + + align:start position:0% +cycle and get rid of all the short + + + align:start position:0% +cycle and get rid of all the short +cycles and this is a way to ensure large + + align:start position:0% +cycles and this is a way to ensure large + + + align:start position:0% +cycles and this is a way to ensure large +growth to obtain High chromatic number + + align:start position:0% +growth to obtain High chromatic number + + + align:start position:0% +growth to obtain High chromatic number +we note that this graph typically + + align:start position:0% +we note that this graph typically + + + align:start position:0% +we note that this graph typically +has typically does not have large + + align:start position:0% +has typically does not have large + + + align:start position:0% +has typically does not have large +independent + + align:start position:0% +independent + + + align:start position:0% +independent +sets and so its independence number is + + align:start position:0% +sets and so its independence number is + + + align:start position:0% +sets and so its independence number is +typically small and therefore the + + align:start position:0% +typically small and therefore the + + + align:start position:0% +typically small and therefore the +independence number of the subgraph must + + align:start position:0% +independence number of the subgraph must + + + align:start position:0% +independence number of the subgraph must +be typically small as well and having + + align:start position:0% +be typically small as well and having + + + align:start position:0% +be typically small as well and having +small Independence number implies High + + align:start position:0% +small Independence number implies High + + + align:start position:0% +small Independence number implies High +chromatic + + align:start position:0% +chromatic + + + align:start position:0% +chromatic +number okay so it's a beautiful + + align:start position:0% +number okay so it's a beautiful + + + align:start position:0% +number okay so it's a beautiful +illustration of the probabilistic method + + align:start position:0% +illustration of the probabilistic method + + + align:start position:0% +illustration of the probabilistic method +with alterations that allows us to + + align:start position:0% +with alterations that allows us to + + + align:start position:0% +with alterations that allows us to +deduce this highly counterintuitive + + align:start position:0% +deduce this highly counterintuitive + + + align:start position:0% +deduce this highly counterintuitive +result + + align:start position:0% +result + + + align:start position:0% +result +which was U quite surprising because in + + align:start position:0% +which was U quite surprising because in + + + align:start position:0% +which was U quite surprising because in +previously various researchers have + + align:start position:0% +previously various researchers have + + + align:start position:0% +previously various researchers have +tried to construct such examples of + + align:start position:0% +tried to construct such examples of + + + align:start position:0% +tried to construct such examples of +graphs by hand explicitly but + + align:start position:0% +graphs by hand explicitly but + + + align:start position:0% +graphs by hand explicitly but +successfully and ERS brought this + + align:start position:0% +successfully and ERS brought this + + + align:start position:0% +successfully and ERS brought this +beautiful Insight that introducing + + align:start position:0% +beautiful Insight that introducing + + + align:start position:0% +beautiful Insight that introducing +Randomness by looking at random graphs + + align:start position:0% +Randomness by looking at random graphs + + + align:start position:0% +Randomness by looking at random graphs +one can indeed prove the existence of + + align:start position:0% +one can indeed prove the existence of + + + align:start position:0% +one can indeed prove the existence of +graphs with highly counterintuitive + + align:start position:0% +graphs with highly counterintuitive + + + align:start position:0% +graphs with highly counterintuitive +properties \ No newline at end of file diff --git a/1KcxRSsHrcI.txt b/1KcxRSsHrcI.txt new file mode 100644 index 0000000000000000000000000000000000000000..78304a2741ed3099c09b3c719bf0180e00764b9d --- /dev/null +++ b/1KcxRSsHrcI.txt @@ -0,0 +1,7883 @@ +align:start position:0% + +so uh last in the last lecture I spent + + align:start position:0% +so uh last in the last lecture I spent + + + align:start position:0% +so uh last in the last lecture I spent +quite a while trying to convey uh a + + align:start position:0% +quite a while trying to convey uh a + + + align:start position:0% +quite a while trying to convey uh a +sense of how the structure of DNA was uh + + align:start position:0% +sense of how the structure of DNA was uh + + + align:start position:0% +sense of how the structure of DNA was uh +discovered um I the data that led the + + align:start position:0% +discovered um I the data that led the + + + align:start position:0% +discovered um I the data that led the +crystalographic data that led to it as I + + align:start position:0% +crystalographic data that led to it as I + + + align:start position:0% +crystalographic data that led to it as I +said was collected by Roslin Franklin + + align:start position:0% +said was collected by Roslin Franklin + + + align:start position:0% +said was collected by Roslin Franklin +and I saw there there's some confusion + + align:start position:0% +and I saw there there's some confusion + + + align:start position:0% +and I saw there there's some confusion +about this picture that I showed you + + align:start position:0% +about this picture that I showed you + + + align:start position:0% +about this picture that I showed you +next this is not a photograph of a + + align:start position:0% +next this is not a photograph of a + + + align:start position:0% +next this is not a photograph of a +double helix this is what happened when + + align:start position:0% +double helix this is what happened when + + + align:start position:0% +double helix this is what happened when +she bounced electron um x-ray off the + + align:start position:0% +she bounced electron um x-ray off the + + + align:start position:0% +she bounced electron um x-ray off the +crystal of DNA this is the defraction + + align:start position:0% +crystal of DNA this is the defraction + + + align:start position:0% +crystal of DNA this is the defraction +pattern that she saw and then one works + + align:start position:0% +pattern that she saw and then one works + + + align:start position:0% +pattern that she saw and then one works +backwards from that trying to figure out + + align:start position:0% +backwards from that trying to figure out + + + align:start position:0% +backwards from that trying to figure out +what kind of structure it was that would + + align:start position:0% +what kind of structure it was that would + + + align:start position:0% +what kind of structure it was that would +have caused that defraction pattern you + + align:start position:0% +have caused that defraction pattern you + + + align:start position:0% +have caused that defraction pattern you +have to be a pretty good ex uh x-ray + + align:start position:0% +have to be a pretty good ex uh x-ray + + + align:start position:0% +have to be a pretty good ex uh x-ray +crystallographer to draw any kind of + + align:start position:0% +crystallographer to draw any kind of + + + align:start position:0% +crystallographer to draw any kind of +inferences from that and there were + + align:start position:0% +inferences from that and there were + + + align:start position:0% +inferences from that and there were +people including uh Francis Crick who + + align:start position:0% +people including uh Francis Crick who + + + align:start position:0% +people including uh Francis Crick who +saw the implications of it right away + + align:start position:0% +saw the implications of it right away + + + align:start position:0% +saw the implications of it right away +but the point was she she collected the + + align:start position:0% +but the point was she she collected the + + + align:start position:0% +but the point was she she collected the +data and then uh the two people that I + + align:start position:0% +data and then uh the two people that I + + + align:start position:0% +data and then uh the two people that I +told you about then who whose names you + + align:start position:0% +told you about then who whose names you + + + align:start position:0% +told you about then who whose names you +know so well Jim Watson and Francis + + align:start position:0% +know so well Jim Watson and Francis + + + align:start position:0% +know so well Jim Watson and Francis +Crick were the two individuals that uh + + align:start position:0% +Crick were the two individuals that uh + + + align:start position:0% +Crick were the two individuals that uh +then solved the uh came up with the + + align:start position:0% +then solved the uh came up with the + + + align:start position:0% +then solved the uh came up with the +model that explained the the defraction + + align:start position:0% +model that explained the the defraction + + + align:start position:0% +model that explained the the defraction +pattern and therefore we learned the the + + align:start position:0% +pattern and therefore we learned the the + + + align:start position:0% +pattern and therefore we learned the the +structure of DNA as a double stranded + + align:start position:0% +structure of DNA as a double stranded + + + align:start position:0% +structure of DNA as a double stranded +Helix I also tried to make the case that + + align:start position:0% +Helix I also tried to make the case that + + + align:start position:0% +Helix I also tried to make the case that +it wasn't two Geniuses who sat down in a + + align:start position:0% +it wasn't two Geniuses who sat down in a + + + align:start position:0% +it wasn't two Geniuses who sat down in a +room took a look at this and popped up + + align:start position:0% +room took a look at this and popped up + + + align:start position:0% +room took a look at this and popped up +with the model it was a story of real + + align:start position:0% +with the model it was a story of real + + + align:start position:0% +with the model it was a story of real +people with Misadventures and mistakes + + align:start position:0% +people with Misadventures and mistakes + + + align:start position:0% +people with Misadventures and mistakes +and recovery from mistakes and so on + + align:start position:0% +and recovery from mistakes and so on + + + align:start position:0% +and recovery from mistakes and so on +getting it it was also uh a very small + + align:start position:0% +getting it it was also uh a very small + + + align:start position:0% +getting it it was also uh a very small +group and I'm going to take just a very + + align:start position:0% +group and I'm going to take just a very + + + align:start position:0% +group and I'm going to take just a very +small minute it's the beginning of the + + align:start position:0% +small minute it's the beginning of the + + + align:start position:0% +small minute it's the beginning of the +uh class because there's I have uh a + + align:start position:0% +uh class because there's I have uh a + + + align:start position:0% +uh class because there's I have uh a +colleague Vernon Ingram who's sitting + + align:start position:0% +colleague Vernon Ingram who's sitting + + + align:start position:0% +colleague Vernon Ingram who's sitting +down here in the front who was in a + + align:start position:0% +down here in the front who was in a + + + align:start position:0% +down here in the front who was in a +member of this very small group of with + + align:start position:0% +member of this very small group of with + + + align:start position:0% +member of this very small group of with +with uh Jim Watson and Francis Crick so + + align:start position:0% +with uh Jim Watson and Francis Crick so + + + align:start position:0% +with uh Jim Watson and Francis Crick so +he was there well where all this + + align:start position:0% +he was there well where all this + + + align:start position:0% +he was there well where all this +happened and almost nobody in the world + + align:start position:0% +happened and almost nobody in the world + + + align:start position:0% +happened and almost nobody in the world +has had a chance in your generation has + + align:start position:0% +has had a chance in your generation has + + + align:start position:0% +has had a chance in your generation has +heard a chance to hear directly from + + align:start position:0% +heard a chance to hear directly from + + + align:start position:0% +heard a chance to hear directly from +somebody who was there when it happened + + align:start position:0% +somebody who was there when it happened + + + align:start position:0% +somebody who was there when it happened +so I ask Vernon if he'd come and just + + align:start position:0% +so I ask Vernon if he'd come and just + + + align:start position:0% +so I ask Vernon if he'd come and just +talk to you for a little bit just what + + align:start position:0% +talk to you for a little bit just what + + + align:start position:0% +talk to you for a little bit just what +it was like to be + + align:start position:0% + + + + align:start position:0% + +there put these onto your sweater + + align:start position:0% +there put these onto your sweater + + + align:start position:0% +there put these onto your sweater +anywhere I guess this I'll + + align:start position:0% +anywhere I guess this I'll + + + align:start position:0% +anywhere I guess this I'll +put pinch it on but + + align:start position:0% +put pinch it on but + + + align:start position:0% +put pinch it on but +there + + align:start position:0% + + + + align:start position:0% + +you want come + + align:start position:0% +you want come + + + align:start position:0% +you want come +back + + align:start position:0% + + + + align:start position:0% + +eventually well thanks Graham um you + + align:start position:0% +eventually well thanks Graham um you + + + align:start position:0% +eventually well thanks Graham um you +seem to be at a very exciting stage in + + align:start position:0% +seem to be at a very exciting stage in + + + align:start position:0% +seem to be at a very exciting stage in +7014 this structure of the secret of + + align:start position:0% +7014 this structure of the secret of + + + align:start position:0% +7014 this structure of the secret of +life no + + align:start position:0% +life no + + + align:start position:0% +life no +less and it's interesting that + + align:start position:0% +less and it's interesting that + + + align:start position:0% +less and it's interesting that +immediately uh when Watson and cck + + align:start position:0% +immediately uh when Watson and cck + + + align:start position:0% +immediately uh when Watson and cck +um put together a + + align:start position:0% +um put together a + + + align:start position:0% +um put together a +model of the DNA + + align:start position:0% +model of the DNA + + + align:start position:0% +model of the DNA +molecule that fit the X-ray data that + + align:start position:0% +molecule that fit the X-ray data that + + + align:start position:0% +molecule that fit the X-ray data that +was the point how do you know a model is + + align:start position:0% +was the point how do you know a model is + + + align:start position:0% +was the point how do you know a model is +correct + + align:start position:0% +correct + + + align:start position:0% +correct +because there are certain distances in + + align:start position:0% +because there are certain distances in + + + align:start position:0% +because there are certain distances in +the model and + + align:start position:0% +the model and + + + align:start position:0% +the model and +those have to correlate + + align:start position:0% +those have to correlate + + + align:start position:0% +those have to correlate +exactly with the + + align:start position:0% +exactly with the + + + align:start position:0% +exactly with the +distances of the X-ray spots in the + + align:start position:0% +distances of the X-ray spots in the + + + align:start position:0% +distances of the X-ray spots in the +defraction pattern that you saw that's + + align:start position:0% +defraction pattern that you saw that's + + + align:start position:0% +defraction pattern that you saw that's +how you know that a model that you've + + align:start position:0% +how you know that a model that you've + + + align:start position:0% +how you know that a model that you've +built to certain + + align:start position:0% +built to certain + + + align:start position:0% +built to certain +specifications corresponds to what the + + align:start position:0% +specifications corresponds to what the + + + align:start position:0% +specifications corresponds to what the +molecule itself in the crystal that + + align:start position:0% +molecule itself in the crystal that + + + align:start position:0% +molecule itself in the crystal that +you're examining + + align:start position:0% +you're examining + + + align:start position:0% +you're examining +actually + + align:start position:0% +actually + + + align:start position:0% +actually +uh is composed + + align:start position:0% +uh is composed + + + align:start position:0% +uh is composed +of it was by sheer accident that I + + align:start position:0% +of it was by sheer accident that I + + + align:start position:0% +of it was by sheer accident that I +happened to be working as a + + align:start position:0% +happened to be working as a + + + align:start position:0% +happened to be working as a +biochemist in uh the MRC medical + + align:start position:0% +biochemist in uh the MRC medical + + + align:start position:0% +biochemist in uh the MRC medical +research Council Lab at the Cavendish + + align:start position:0% +research Council Lab at the Cavendish + + + align:start position:0% +research Council Lab at the Cavendish +laboratory where Watson and Crick um + + align:start position:0% +laboratory where Watson and Crick um + + + align:start position:0% +laboratory where Watson and Crick um +were working sheer accident it was a + + align:start position:0% +were working sheer accident it was a + + + align:start position:0% +were working sheer accident it was a +very crowed lab as Graham + + align:start position:0% +very crowed lab as Graham + + + align:start position:0% +very crowed lab as Graham +said and that's something that you + + align:start position:0% +said and that's something that you + + + align:start position:0% +said and that's something that you +should + + align:start position:0% +should + + + align:start position:0% +should +remember when you're choosing a lab to + + align:start position:0% +remember when you're choosing a lab to + + + align:start position:0% +remember when you're choosing a lab to +work + + align:start position:0% +work + + + align:start position:0% +work +in always go to a lab that's + + align:start position:0% +in always go to a lab that's + + + align:start position:0% +in always go to a lab that's +overcrowded never go to a lab where + + align:start position:0% +overcrowded never go to a lab where + + + align:start position:0% +overcrowded never go to a lab where +there's lots of + + align:start position:0% +there's lots of + + + align:start position:0% +there's lots of +space + + align:start position:0% +space + + + align:start position:0% +space +because a really successful lab attracts + + align:start position:0% +because a really successful lab attracts + + + align:start position:0% +because a really successful lab attracts +so + + align:start position:0% +so + + + align:start position:0% +so +many co-workers visitors that it rapidly + + align:start position:0% +many co-workers visitors that it rapidly + + + align:start position:0% +many co-workers visitors that it rapidly +gets overcrowded and that was the case + + align:start position:0% +gets overcrowded and that was the case + + + align:start position:0% +gets overcrowded and that was the case +in this uh in this + + align:start position:0% +in this uh in this + + + align:start position:0% +in this uh in this +laboratory the director was Max perutz + + align:start position:0% +laboratory the director was Max perutz + + + align:start position:0% +laboratory the director was Max perutz +co-director John kendrew doing x-ray + + align:start position:0% +co-director John kendrew doing x-ray + + + align:start position:0% +co-director John kendrew doing x-ray +crystallography of uh proteins for + + align:start position:0% +crystallography of uh proteins for + + + align:start position:0% +crystallography of uh proteins for +almost the first time and solving the + + align:start position:0% +almost the first time and solving the + + + align:start position:0% +almost the first time and solving the +protein + + align:start position:0% +protein + + + align:start position:0% +protein +structure uh Francis criek was a + + align:start position:0% +structure uh Francis criek was a + + + align:start position:0% +structure uh Francis criek was a +graduate student of U Max perutz doing + + align:start position:0% +graduate student of U Max perutz doing + + + align:start position:0% +graduate student of U Max perutz doing +PhD work and the first thing I remember + + align:start position:0% +PhD work and the first thing I remember + + + align:start position:0% +PhD work and the first thing I remember +about + + align:start position:0% +about + + + align:start position:0% +about +Francis was when I went there as a + + align:start position:0% +Francis was when I went there as a + + + align:start position:0% +Francis was when I went there as a +biochemist to work with Max PRS when I + + align:start position:0% +biochemist to work with Max PRS when I + + + align:start position:0% +biochemist to work with Max PRS when I +went there there was this tall gangling + + align:start position:0% +went there there was this tall gangling + + + align:start position:0% +went there there was this tall gangling +guy constantly circulating between the + + align:start position:0% +guy constantly circulating between the + + + align:start position:0% +guy constantly circulating between the +top floor of the + + align:start position:0% +top floor of the + + + align:start position:0% +top floor of the +building his office in the middle and + + align:start position:0% +building his office in the middle and + + + align:start position:0% +building his office in the middle and +the X-ray machines at the bottom is + + align:start position:0% +the X-ray machines at the bottom is + + + align:start position:0% +the X-ray machines at the bottom is +constantly going up and down and in + + align:start position:0% +constantly going up and down and in + + + align:start position:0% +constantly going up and down and in +those days the buildings didn't have any + + align:start position:0% +those days the buildings didn't have any + + + align:start position:0% +those days the buildings didn't have any +elevators or lifts as the English call + + align:start position:0% +elevators or lifts as the English call + + + align:start position:0% +elevators or lifts as the English call +them so he was in excellent physical + + align:start position:0% +them so he was in excellent physical + + + align:start position:0% +them so he was in excellent physical +shape + + align:start position:0% +shape + + + align:start position:0% +shape +uh very crowded a very modest lab and + + align:start position:0% +uh very crowded a very modest lab and + + + align:start position:0% +uh very crowded a very modest lab and +what's usually + + align:start position:0% +what's usually + + + align:start position:0% +what's usually +forgotten is a key member of that group + + align:start position:0% +forgotten is a key member of that group + + + align:start position:0% +forgotten is a key member of that group +an engineer Tony + + align:start position:0% +an engineer Tony + + + align:start position:0% +an engineer Tony +broad key person because he invented + + align:start position:0% +broad key person because he invented + + + align:start position:0% +broad key person because he invented +what was then the world's best and most + + align:start position:0% +what was then the world's best and most + + + align:start position:0% +what was then the world's best and most +efficient x-ray machine a rotating anode + + align:start position:0% +efficient x-ray machine a rotating anode + + + align:start position:0% +efficient x-ray machine a rotating anode +x-ray machine and it because to the + + align:start position:0% +x-ray machine and it because to the + + + align:start position:0% +x-ray machine and it because to the +X-ray crystallographers in that group + + align:start position:0% +X-ray crystallographers in that group + + + align:start position:0% +X-ray crystallographers in that group +this machine was + + align:start position:0% +this machine was + + + align:start position:0% +this machine was +available because of that they were the + + align:start position:0% +available because of that they were the + + + align:start position:0% +available because of that they were the +preeminent x-ray structure group in the + + align:start position:0% +preeminent x-ray structure group in the + + + align:start position:0% +preeminent x-ray structure group in the +world my job was as a bi biochemist + + align:start position:0% +world my job was as a bi biochemist + + + align:start position:0% +world my job was as a bi biochemist +protein + + align:start position:0% +protein + + + align:start position:0% +protein +biochemist uh putting a heavy atom + + align:start position:0% +biochemist uh putting a heavy atom + + + align:start position:0% +biochemist uh putting a heavy atom +Mercury very heavy atom into max + + align:start position:0% +Mercury very heavy atom into max + + + align:start position:0% +Mercury very heavy atom into max +perutz's hemoglobin crystals in specific + + align:start position:0% +perutz's hemoglobin crystals in specific + + + align:start position:0% +perutz's hemoglobin crystals in specific +places that has a predictable effect on + + align:start position:0% +places that has a predictable effect on + + + align:start position:0% +places that has a predictable effect on +the X-ray pattern and that enables the + + align:start position:0% +the X-ray pattern and that enables the + + + align:start position:0% +the X-ray pattern and that enables the +FIA diagram to be uh constructed with + + align:start position:0% +FIA diagram to be uh constructed with + + + align:start position:0% +FIA diagram to be uh constructed with +real phase values for the X-ray + + align:start position:0% +real phase values for the X-ray + + + align:start position:0% +real phase values for the X-ray +diffractions um for the physicists among + + align:start position:0% +diffractions um for the physicists among + + + align:start position:0% +diffractions um for the physicists among +you here are there any physicists here + + align:start position:0% +you here are there any physicists here + + + align:start position:0% +you here are there any physicists here +yeah thought + + align:start position:0% +yeah thought + + + align:start position:0% +yeah thought +so um that was a big step + + align:start position:0% +so um that was a big step + + + align:start position:0% +so um that was a big step +forward and that was also a big step in + + align:start position:0% +forward and that was also a big step in + + + align:start position:0% +forward and that was also a big step in +uh figuring out um the structure of the + + align:start position:0% +uh figuring out um the structure of the + + + align:start position:0% +uh figuring out um the structure of the +DNA uh + + align:start position:0% +DNA uh + + + align:start position:0% +DNA uh +samples semi + + align:start position:0% +samples semi + + + align:start position:0% +samples semi +crystals that uh Professor walker uh + + align:start position:0% +crystals that uh Professor walker uh + + + align:start position:0% +crystals that uh Professor walker uh +just referred + + align:start position:0% +just referred + + + align:start position:0% +just referred +to all dependent on the engineer Tony + + align:start position:0% +to all dependent on the engineer Tony + + + align:start position:0% +to all dependent on the engineer Tony +broad who's never mentioned in any of + + align:start position:0% +broad who's never mentioned in any of + + + align:start position:0% +broad who's never mentioned in any of +these histories but without him this + + align:start position:0% +these histories but without him this + + + align:start position:0% +these histories but without him this +would not have happened so it was an + + align:start position:0% +would not have happened so it was an + + + align:start position:0% +would not have happened so it was an +exciting place to work in very exciting + + align:start position:0% +exciting place to work in very exciting + + + align:start position:0% +exciting place to work in very exciting +we were all young in those + + align:start position:0% +we were all young in those + + + align:start position:0% +we were all young in those +days and living the lives of young men + + align:start position:0% +days and living the lives of young men + + + align:start position:0% +days and living the lives of young men +and young + + align:start position:0% +and young + + + align:start position:0% +and young +women with all the + + align:start position:0% +women with all the + + + align:start position:0% +women with all the +complications that arise when you put a + + align:start position:0% +complications that arise when you put a + + + align:start position:0% +complications that arise when you put a +whole bunch of very energetic young men + + align:start position:0% +whole bunch of very energetic young men + + + align:start position:0% +whole bunch of very energetic young men +very energetic young women together and + + align:start position:0% +very energetic young women together and + + + align:start position:0% +very energetic young women together and +by that I mean the + + align:start position:0% +by that I mean the + + + align:start position:0% +by that I mean the +interpersonal + + align:start position:0% +interpersonal + + + align:start position:0% +interpersonal +relationships which when you're in a + + align:start position:0% +relationships which when you're in a + + + align:start position:0% +relationships which when you're in a +crowded very active + + align:start position:0% +crowded very active + + + align:start position:0% +crowded very active +situation um can sometimes + + align:start position:0% +situation um can sometimes + + + align:start position:0% +situation um can sometimes +interfere and we're always very + + align:start position:0% +interfere and we're always very + + + align:start position:0% +interfere and we're always very +entertaining I can tell you that I could + + align:start position:0% +entertaining I can tell you that I could + + + align:start position:0% +entertaining I can tell you that I could +tell you give you a chapter and verse + + align:start position:0% +tell you give you a chapter and verse + + + align:start position:0% +tell you give you a chapter and verse +but it isn't really so very different + + align:start position:0% +but it isn't really so very different + + + align:start position:0% +but it isn't really so very different +from people your age now right I mean + + align:start position:0% +from people your age now right I mean + + + align:start position:0% +from people your age now right I mean +that I'm not saying it interferes with + + align:start position:0% +that I'm not saying it interferes with + + + align:start position:0% +that I'm not saying it interferes with +you sometimes it might there an exciting + + align:start position:0% +you sometimes it might there an exciting + + + align:start position:0% +you sometimes it might there an exciting +lab an exciting time to be there + + align:start position:0% +lab an exciting time to be there + + + align:start position:0% +lab an exciting time to be there +because we were not the only + + align:start position:0% +because we were not the only + + + align:start position:0% +because we were not the only +group uh trying to figure out the + + align:start position:0% +group uh trying to figure out the + + + align:start position:0% +group uh trying to figure out the +structure of + + align:start position:0% +structure of + + + align:start position:0% +structure of +DNA a huge competitor was lonus Pauling + + align:start position:0% +DNA a huge competitor was lonus Pauling + + + align:start position:0% +DNA a huge competitor was lonus Pauling +at + + align:start position:0% +at + + + align:start position:0% +at +Caltech who had beaten that same group + + align:start position:0% +Caltech who had beaten that same group + + + align:start position:0% +Caltech who had beaten that same group +once before quite recently over the + + align:start position:0% +once before quite recently over the + + + align:start position:0% +once before quite recently over the +alpha Helix the component of the crucial + + align:start position:0% +alpha Helix the component of the crucial + + + align:start position:0% +alpha Helix the component of the crucial +component of protein structure he got + + align:start position:0% +component of protein structure he got + + + align:start position:0% +component of protein structure he got +the right answer first 1.5 angstrom + + align:start position:0% +the right answer first 1.5 angstrom + + + align:start position:0% +the right answer first 1.5 angstrom +reflection the alpha Helix but and our + + align:start position:0% +reflection the alpha Helix but and our + + + align:start position:0% +reflection the alpha Helix but and our +group Max perut and our group had been + + align:start position:0% +group Max perut and our group had been + + + align:start position:0% +group Max perut and our group had been +wrong so the group was smarting under + + align:start position:0% +wrong so the group was smarting under + + + align:start position:0% +wrong so the group was smarting under +that kind of defeat if you like and + + align:start position:0% +that kind of defeat if you like and + + + align:start position:0% +that kind of defeat if you like and +competition uh is a wonderful SP spur as + + align:start position:0% +competition uh is a wonderful SP spur as + + + align:start position:0% +competition uh is a wonderful SP spur as +long as you don't let it get out of hand + + align:start position:0% +long as you don't let it get out of hand + + + align:start position:0% +long as you don't let it get out of hand +well needless to say we didn't but uh + + align:start position:0% +well needless to say we didn't but uh + + + align:start position:0% +well needless to say we didn't but uh +the the competition with the with the um + + align:start position:0% +the the competition with the with the um + + + align:start position:0% +the the competition with the with the um +uh polling lab was certainly so severe + + align:start position:0% +uh polling lab was certainly so severe + + + align:start position:0% +uh polling lab was certainly so severe +that we awaited the next letter you see + + align:start position:0% +that we awaited the next letter you see + + + align:start position:0% +that we awaited the next letter you see +in those days new scientific + + align:start position:0% +in those days new scientific + + + align:start position:0% +in those days new scientific +information arrived not by Publications + + align:start position:0% +information arrived not by Publications + + + align:start position:0% +information arrived not by Publications +that took much too long but by personal + + align:start position:0% +that took much too long but by personal + + + align:start position:0% +that took much too long but by personal +letter and in fact the NIH has put + + align:start position:0% +letter and in fact the NIH has put + + + align:start position:0% +letter and in fact the NIH has put +together all these various letters in + + align:start position:0% +together all these various letters in + + + align:start position:0% +together all these various letters in +the Francis criek + + align:start position:0% +the Francis criek + + + align:start position:0% +the Francis criek +collection and when you have time you + + align:start position:0% +collection and when you have time you + + + align:start position:0% +collection and when you have time you +should look at those they're quite + + align:start position:0% +should look at those they're quite + + + align:start position:0% +should look at those they're quite +interesting because they tell you in a + + align:start position:0% +interesting because they tell you in a + + + align:start position:0% +interesting because they tell you in a +way a scientific paper does not tell + + align:start position:0% +way a scientific paper does not tell + + + align:start position:0% +way a scientific paper does not tell +you what I feel about my experimental + + align:start position:0% +you what I feel about my experimental + + + align:start position:0% +you what I feel about my experimental +result what she feels about her + + align:start position:0% +result what she feels about her + + + align:start position:0% +result what she feels about her +experimental results what it means to me + + align:start position:0% +experimental results what it means to me + + + align:start position:0% +experimental results what it means to me +as a person to her as a person to him as + + align:start position:0% +as a person to her as a person to him as + + + align:start position:0% +as a person to her as a person to him as +a + + align:start position:0% +a + + + align:start position:0% +a +person so we were constantly watching + + align:start position:0% +person so we were constantly watching + + + align:start position:0% +person so we were constantly watching +the + + align:start position:0% +the + + + align:start position:0% +the +mail and discussing the news as it came + + align:start position:0% +mail and discussing the news as it came + + + align:start position:0% +mail and discussing the news as it came +in mostly over a beer at the pub next + + align:start position:0% +in mostly over a beer at the pub next + + + align:start position:0% +in mostly over a beer at the pub next +door it was very conveniently Lo + + align:start position:0% +door it was very conveniently Lo + + + align:start position:0% +door it was very conveniently Lo +located but being a small group crowded + + align:start position:0% +located but being a small group crowded + + + align:start position:0% +located but being a small group crowded +Together made communication within our + + align:start position:0% +Together made communication within our + + + align:start position:0% +Together made communication within our +group very easy indeed and we had fights + + align:start position:0% +group very easy indeed and we had fights + + + align:start position:0% +group very easy indeed and we had fights +I don't mean physical fights we had + + align:start position:0% +I don't mean physical fights we had + + + align:start position:0% +I don't mean physical fights we had +fights scientific fights and + + align:start position:0% +fights scientific fights and + + + align:start position:0% +fights scientific fights and +um as a biochemist I was able to settle + + align:start position:0% +um as a biochemist I was able to settle + + + align:start position:0% +um as a biochemist I was able to settle +a crucial fight among the + + align:start position:0% +a crucial fight among the + + + align:start position:0% +a crucial fight among the +crystallographers Crick and Watson who + + align:start position:0% +crystallographers Crick and Watson who + + + align:start position:0% +crystallographers Crick and Watson who +were building the model because quite + + align:start position:0% +were building the model because quite + + + align:start position:0% +were building the model because quite +frankly they didn't do Know Much + + align:start position:0% +frankly they didn't do Know Much + + + align:start position:0% +frankly they didn't do Know Much +Chemistry and we're trying to build a + + align:start position:0% +Chemistry and we're trying to build a + + + align:start position:0% +Chemistry and we're trying to build a +model with a wrong confirmation of the + + align:start position:0% +model with a wrong confirmation of the + + + align:start position:0% +model with a wrong confirmation of the +peptide bond they didn't realize that a + + align:start position:0% +peptide bond they didn't realize that a + + + align:start position:0% +peptide bond they didn't realize that a +peptide bond has two possible + + align:start position:0% +peptide bond has two possible + + + align:start position:0% +peptide bond has two possible +confirmations and they had at one point + + align:start position:0% +confirmations and they had at one point + + + align:start position:0% +confirmations and they had at one point +a terrible time + + align:start position:0% +a terrible time + + + align:start position:0% +a terrible time +um uh trying to fit everything together + + align:start position:0% +um uh trying to fit everything together + + + align:start position:0% +um uh trying to fit everything together +because they were using the wrong + + align:start position:0% +because they were using the wrong + + + align:start position:0% +because they were using the wrong +confirmation I'm talking about laam + + align:start position:0% +confirmation I'm talking about laam + + + align:start position:0% +confirmation I'm talking about laam +latim uh for those of you who are + + align:start position:0% +latim uh for those of you who are + + + align:start position:0% +latim uh for those of you who are +organic chemists that mean something + + align:start position:0% +organic chemists that mean something + + + align:start position:0% +organic chemists that mean something +confirmation and once they got the right + + align:start position:0% +confirmation and once they got the right + + + align:start position:0% +confirmation and once they got the right +confirmation then the model clicked into + + align:start position:0% +confirmation then the model clicked into + + + align:start position:0% +confirmation then the model clicked into +place so we all helped that's what I'm + + align:start position:0% +place so we all helped that's what I'm + + + align:start position:0% +place so we all helped that's what I'm +trying to say we all helped with one + + align:start position:0% +trying to say we all helped with one + + + align:start position:0% +trying to say we all helped with one +great aim in mind it was clear and you + + align:start position:0% +great aim in mind it was clear and you + + + align:start position:0% +great aim in mind it was clear and you +know from what Professor Walker said + + align:start position:0% +know from what Professor Walker said + + + align:start position:0% +know from what Professor Walker said +that the DNA structure + + align:start position:0% +that the DNA structure + + + align:start position:0% +that the DNA structure +in its structure held the clue to + + align:start position:0% +in its structure held the clue to + + + align:start position:0% +in its structure held the clue to +crucial physiological behavior of + + align:start position:0% +crucial physiological behavior of + + + align:start position:0% +crucial physiological behavior of +DNA + + align:start position:0% +DNA + + + align:start position:0% +DNA +and um KCK and Watson said this in their + + align:start position:0% +and um KCK and Watson said this in their + + + align:start position:0% +and um KCK and Watson said this in their +first paper the structure itself because + + align:start position:0% +first paper the structure itself because + + + align:start position:0% +first paper the structure itself because +of its + + align:start position:0% +of its + + + align:start position:0% +of its +complementarity gives you an immediate + + align:start position:0% +complementarity gives you an immediate + + + align:start position:0% +complementarity gives you an immediate +clue as to how it + + align:start position:0% +clue as to how it + + + align:start position:0% +clue as to how it +replicates and replication of DNA + + align:start position:0% +replicates and replication of DNA + + + align:start position:0% +replicates and replication of DNA +structure from generation to + + align:start position:0% +structure from generation to + + + align:start position:0% +structure from generation to +generation is + + align:start position:0% +generation is + + + align:start position:0% +generation is +um of course the crucial thing about + + align:start position:0% +um of course the crucial thing about + + + align:start position:0% +um of course the crucial thing about +DNA the copying the precise copying from + + align:start position:0% +DNA the copying the precise copying from + + + align:start position:0% +DNA the copying the precise copying from +generation to generation and that fell + + align:start position:0% +generation to generation and that fell + + + align:start position:0% +generation to generation and that fell +out of the X-ray structure that's why + + align:start position:0% +out of the X-ray structure that's why + + + align:start position:0% +out of the X-ray structure that's why +the X-ray structure was so very + + align:start position:0% +the X-ray structure was so very + + + align:start position:0% +the X-ray structure was so very +important because it gave you an + + align:start position:0% +important because it gave you an + + + align:start position:0% +important because it gave you an +immediate understanding of uh the role + + align:start position:0% +immediate understanding of uh the role + + + align:start position:0% +immediate understanding of uh the role +of DNA in Modern Biology so that's what + + align:start position:0% +of DNA in Modern Biology so that's what + + + align:start position:0% +of DNA in Modern Biology so that's what +we did and eventually um the people in + + align:start position:0% +we did and eventually um the people in + + + align:start position:0% +we did and eventually um the people in +the group the group got so overcrowded + + align:start position:0% +the group the group got so overcrowded + + + align:start position:0% +the group the group got so overcrowded +they built a huge lab and that's very + + align:start position:0% +they built a huge lab and that's very + + + align:start position:0% +they built a huge lab and that's very +beautiful like any new lab is but the + + align:start position:0% +beautiful like any new lab is but the + + + align:start position:0% +beautiful like any new lab is but the +thing I remember most of all was the + + align:start position:0% +thing I remember most of all was the + + + align:start position:0% +thing I remember most of all was the +atmosphere in that place so remember + + align:start position:0% +atmosphere in that place so remember + + + align:start position:0% +atmosphere in that place so remember +when you go and choose a lab choose one + + align:start position:0% +when you go and choose a lab choose one + + + align:start position:0% +when you go and choose a lab choose one +that's overcrowded it'll pay + + align:start position:0% + + + + align:start position:0% + +off + + align:start position:0% + + + + align:start position:0% + +so much that was really wonderful thank + + align:start position:0% + + + + align:start position:0% + +you + + align:start position:0% +you + + + align:start position:0% +you +I don't know if some of you realize + + align:start position:0% +I don't know if some of you realize + + + align:start position:0% +I don't know if some of you realize +quite how rare that was this discovery + + align:start position:0% +quite how rare that was this discovery + + + align:start position:0% +quite how rare that was this discovery +of the structure of DNA as I said + + align:start position:0% +of the structure of DNA as I said + + + align:start position:0% +of the structure of DNA as I said +probably one of the big discoveries of + + align:start position:0% +probably one of the big discoveries of + + + align:start position:0% +probably one of the big discoveries of +mankind because as Vernon said so much + + align:start position:0% +mankind because as Vernon said so much + + + align:start position:0% +mankind because as Vernon said so much +it was you could see so many of the + + align:start position:0% +it was you could see so many of the + + + align:start position:0% +it was you could see so many of the +secrets of life as soon as you saw that + + align:start position:0% +secrets of life as soon as you saw that + + + align:start position:0% +secrets of life as soon as you saw that +structure very few people have ever + + align:start position:0% +structure very few people have ever + + + align:start position:0% +structure very few people have ever +heard from someone who was there at the + + align:start position:0% +heard from someone who was there at the + + + align:start position:0% +heard from someone who was there at the +time maybe you'll forget a bunch of + + align:start position:0% +time maybe you'll forget a bunch of + + + align:start position:0% +time maybe you'll forget a bunch of +stuff down the line I hope you'll + + align:start position:0% +stuff down the line I hope you'll + + + align:start position:0% +stuff down the line I hope you'll +remember you heard somebody was there + + align:start position:0% +remember you heard somebody was there + + + align:start position:0% +remember you heard somebody was there +when won and Crick were there and maybe + + align:start position:0% +when won and Crick were there and maybe + + + align:start position:0% +when won and Crick were there and maybe +his extra piece advice about choosing a + + align:start position:0% +his extra piece advice about choosing a + + + align:start position:0% +his extra piece advice about choosing a +lab um just say one thing quickly some + + align:start position:0% +lab um just say one thing quickly some + + + align:start position:0% +lab um just say one thing quickly some +of you I think understood what I've been + + align:start position:0% +of you I think understood what I've been + + + align:start position:0% +of you I think understood what I've been +trying to do I spent quite a bit of time + + align:start position:0% +trying to do I spent quite a bit of time + + + align:start position:0% +trying to do I spent quite a bit of time +talking about science being done by real + + align:start position:0% +talking about science being done by real + + + align:start position:0% +talking about science being done by real +people real uh doing real + + align:start position:0% +people real uh doing real + + + align:start position:0% +people real uh doing real +experiments uh thanks for your comments + + align:start position:0% +experiments uh thanks for your comments + + + align:start position:0% +experiments uh thanks for your comments +a few of you have gone out of your way + + align:start position:0% +a few of you have gone out of your way + + + align:start position:0% +a few of you have gone out of your way +to say that this was a total waste of + + align:start position:0% +to say that this was a total waste of + + + align:start position:0% +to say that this was a total waste of +time and you didn't understand why I + + align:start position:0% +time and you didn't understand why I + + + align:start position:0% +time and you didn't understand why I +didn't teach you something instead of + + align:start position:0% +didn't teach you something instead of + + + align:start position:0% +didn't teach you something instead of +doing something on the test well I'm + + align:start position:0% +doing something on the test well I'm + + + align:start position:0% +doing something on the test well I'm +making up the test and if you don't + + align:start position:0% +making up the test and if you don't + + + align:start position:0% +making up the test and if you don't +think there'll be something on + + align:start position:0% +think there'll be something on + + + align:start position:0% +think there'll be something on +scientific process on the the second + + align:start position:0% +scientific process on the the second + + + align:start position:0% +scientific process on the the second +exam you'll be surprised so uh I'm I'm + + align:start position:0% +exam you'll be surprised so uh I'm I'm + + + align:start position:0% +exam you'll be surprised so uh I'm I'm +spending a lot of time on this and the + + align:start position:0% +spending a lot of time on this and the + + + align:start position:0% +spending a lot of time on this and the +reason is because you're MIT students + + align:start position:0% +reason is because you're MIT students + + + align:start position:0% +reason is because you're MIT students +you know you can go many places in the + + align:start position:0% +you know you can go many places in the + + + align:start position:0% +you know you can go many places in the +country many high school biology courses + + align:start position:0% +country many high school biology courses + + + align:start position:0% +country many high school biology courses +and you can memorize all the someone + + align:start position:0% +and you can memorize all the someone + + + align:start position:0% +and you can memorize all the someone +will tell you to memorize everything + + align:start position:0% +will tell you to memorize everything + + + align:start position:0% +will tell you to memorize everything +that's in the book and you'll get tested + + align:start position:0% +that's in the book and you'll get tested + + + align:start position:0% +that's in the book and you'll get tested +whether you can memorize it if you guys + + align:start position:0% +whether you can memorize it if you guys + + + align:start position:0% +whether you can memorize it if you guys +are at MIT because you have the + + align:start position:0% +are at MIT because you have the + + + align:start position:0% +are at MIT because you have the +potential to be leaders in whatever you + + align:start position:0% +potential to be leaders in whatever you + + + align:start position:0% +potential to be leaders in whatever you +do I've made the transition from being + + align:start position:0% +do I've made the transition from being + + + align:start position:0% +do I've made the transition from being +an undergrad sort of trying to memorize + + align:start position:0% +an undergrad sort of trying to memorize + + + align:start position:0% +an undergrad sort of trying to memorize +stuff in a textbook to working on a + + align:start position:0% +stuff in a textbook to working on a + + + align:start position:0% +stuff in a textbook to working on a +Cutting Edge I've made some reasonably + + align:start position:0% +Cutting Edge I've made some reasonably + + + align:start position:0% +Cutting Edge I've made some reasonably +significant discoveries in science as + + align:start position:0% +significant discoveries in science as + + + align:start position:0% +significant discoveries in science as +have my other colleagues in the + + align:start position:0% +have my other colleagues in the + + + align:start position:0% +have my other colleagues in the +department some of them making greater + + align:start position:0% +department some of them making greater + + + align:start position:0% +department some of them making greater +than I but nevertheless if you're on + + align:start position:0% +than I but nevertheless if you're on + + + align:start position:0% +than I but nevertheless if you're on +that Cutting Edge then you're dealing + + align:start position:0% +that Cutting Edge then you're dealing + + + align:start position:0% +that Cutting Edge then you're dealing +with all the stuff I'm trying to tell + + align:start position:0% +with all the stuff I'm trying to tell + + + align:start position:0% +with all the stuff I'm trying to tell +you about in in in this thing you're + + align:start position:0% +you about in in in this thing you're + + + align:start position:0% +you about in in in this thing you're +working as part of a groups there's + + align:start position:0% +working as part of a groups there's + + + align:start position:0% +working as part of a groups there's +competition there's interpersonal + + align:start position:0% +competition there's interpersonal + + + align:start position:0% +competition there's interpersonal +relationship you make mistakes you + + align:start position:0% +relationship you make mistakes you + + + align:start position:0% +relationship you make mistakes you +recover from them you're making + + align:start position:0% +recover from them you're making + + + align:start position:0% +recover from them you're making +inferences you're testing models it's a + + align:start position:0% +inferences you're testing models it's a + + + align:start position:0% +inferences you're testing models it's a +very complex very real very Dynamic very + + align:start position:0% +very complex very real very Dynamic very + + + align:start position:0% +very complex very real very Dynamic very +human uh interaction I hope you caught a + + align:start position:0% +human uh interaction I hope you caught a + + + align:start position:0% +human uh interaction I hope you caught a +little bit of a whiff of that that from + + align:start position:0% +little bit of a whiff of that that from + + + align:start position:0% +little bit of a whiff of that that from +uh from uh from Vernon and I wouldn't be + + align:start position:0% +uh from uh from Vernon and I wouldn't be + + + align:start position:0% +uh from uh from Vernon and I wouldn't be +I I'm quite capable of reproducing + + align:start position:0% +I I'm quite capable of reproducing + + + align:start position:0% +I I'm quite capable of reproducing +diagrams from the textbook without + + align:start position:0% +diagrams from the textbook without + + + align:start position:0% +diagrams from the textbook without +trying to give you a deeper + + align:start position:0% +trying to give you a deeper + + + align:start position:0% +trying to give you a deeper +understanding and that's what I'm trying + + align:start position:0% +understanding and that's what I'm trying + + + align:start position:0% +understanding and that's what I'm trying +to do here and I hope uh if it hasn't + + align:start position:0% +to do here and I hope uh if it hasn't + + + align:start position:0% +to do here and I hope uh if it hasn't +made sense to you by the end is at least + + align:start position:0% +made sense to you by the end is at least + + + align:start position:0% +made sense to you by the end is at least +a few more of you will will get it and + + align:start position:0% +a few more of you will will get it and + + + align:start position:0% +a few more of you will will get it and +those of you who I think saw what I was + + align:start position:0% +those of you who I think saw what I was + + + align:start position:0% +those of you who I think saw what I was +doing um I appreciate your your uh + + align:start position:0% +doing um I appreciate your your uh + + + align:start position:0% +doing um I appreciate your your uh +you're telling me that in the in the + + align:start position:0% +you're telling me that in the in the + + + align:start position:0% +you're telling me that in the in the +things these are Anonymous so I don't + + align:start position:0% +things these are Anonymous so I don't + + + align:start position:0% +things these are Anonymous so I don't +know but you know a couple of you are + + align:start position:0% +know but you know a couple of you are + + + align:start position:0% +know but you know a couple of you are +certainly trying to to make it clear + + align:start position:0% +certainly trying to to make it clear + + + align:start position:0% +certainly trying to to make it clear +that you didn't think it was um uh was + + align:start position:0% +that you didn't think it was um uh was + + + align:start position:0% +that you didn't think it was um uh was +worth your time coming to lecture I'm + + align:start position:0% +worth your time coming to lecture I'm + + + align:start position:0% +worth your time coming to lecture I'm +trying to tell you why I'm trying to do + + align:start position:0% +trying to tell you why I'm trying to do + + + align:start position:0% +trying to tell you why I'm trying to do +it I'm trying to te Teach You in a + + align:start position:0% +it I'm trying to te Teach You in a + + + align:start position:0% +it I'm trying to te Teach You in a +deeper way that's what I'm this is a + + align:start position:0% +deeper way that's what I'm this is a + + + align:start position:0% +deeper way that's what I'm this is a +required course it's important for your + + align:start position:0% +required course it's important for your + + + align:start position:0% +required course it's important for your +life I hope some of you will see that or + + align:start position:0% +life I hope some of you will see that or + + + align:start position:0% +life I hope some of you will see that or +if you don't see it now you'll see it + + align:start position:0% +if you don't see it now you'll see it + + + align:start position:0% +if you don't see it now you'll see it +later in your career okay now we're + + align:start position:0% +later in your career okay now we're + + + align:start position:0% +later in your career okay now we're +going to talk about uh DNA replication + + align:start position:0% +going to talk about uh DNA replication + + + align:start position:0% +going to talk about uh DNA replication +I'm going to start to drive into some of + + align:start position:0% +I'm going to start to drive into some of + + + align:start position:0% +I'm going to start to drive into some of +the details that maybe are more of the + + align:start position:0% +the details that maybe are more of the + + + align:start position:0% +the details that maybe are more of the +kind of things you're expecting just + + align:start position:0% +kind of things you're expecting just + + + align:start position:0% +kind of things you're expecting just +want to make one quick Point here I've + + align:start position:0% +want to make one quick Point here I've + + + align:start position:0% +want to make one quick Point here I've +talked about cell division we saw this + + align:start position:0% +talked about cell division we saw this + + + align:start position:0% +talked about cell division we saw this +how cells come from other cells go on to + + align:start position:0% +how cells come from other cells go on to + + + align:start position:0% +how cells come from other cells go on to +make more cells I showed you this little + + align:start position:0% +make more cells I showed you this little + + + align:start position:0% +make more cells I showed you this little +movie you've seen a few times of a of a + + align:start position:0% +movie you've seen a few times of a of a + + + align:start position:0% +movie you've seen a few times of a of a +yeast cell dividing but all cells divide + + align:start position:0% +yeast cell dividing but all cells divide + + + align:start position:0% +yeast cell dividing but all cells divide +here's a cancer cell + + align:start position:0% + + + + align:start position:0% + +dividing if you get a cancer it's a cell + + align:start position:0% +dividing if you get a cancer it's a cell + + + align:start position:0% +dividing if you get a cancer it's a cell +that's forgotten how to stop dividing + + align:start position:0% +that's forgotten how to stop dividing + + + align:start position:0% +that's forgotten how to stop dividing +and it's growing to make a tumor there's + + align:start position:0% +and it's growing to make a tumor there's + + + align:start position:0% +and it's growing to make a tumor there's +a cancer cell dividing looks not unlike + + align:start position:0% +a cancer cell dividing looks not unlike + + + align:start position:0% +a cancer cell dividing looks not unlike +a yeast and very molecular level very + + align:start position:0% +a yeast and very molecular level very + + + align:start position:0% +a yeast and very molecular level very +very similar but there's another point I + + align:start position:0% +very similar but there's another point I + + + align:start position:0% +very similar but there's another point I +told you the how the structure of DNA + + align:start position:0% +told you the how the structure of DNA + + + align:start position:0% +told you the how the structure of DNA +with the complimentary strands with G + + align:start position:0% +with the complimentary strands with G + + + align:start position:0% +with the complimentary strands with G +pairing with c and a pairing with t + + align:start position:0% +pairing with c and a pairing with t + + + align:start position:0% +pairing with c and a pairing with t +immediately gave rise to an insight as + + align:start position:0% +immediately gave rise to an insight as + + + align:start position:0% +immediately gave rise to an insight as +to how the the genetic material could be + + align:start position:0% +to how the the genetic material could be + + + align:start position:0% +to how the the genetic material could be +replicated and you guys know that it's + + align:start position:0% +replicated and you guys know that it's + + + align:start position:0% +replicated and you guys know that it's +held together by hydrogen bonds between + + align:start position:0% +held together by hydrogen bonds between + + + align:start position:0% +held together by hydrogen bonds between +the base pairs which are about 12/ 12th + + align:start position:0% +the base pairs which are about 12/ 12th + + + align:start position:0% +the base pairs which are about 12/ 12th +the strength of the calent bonds so + + align:start position:0% +the strength of the calent bonds so + + + align:start position:0% +the strength of the calent bonds so +you're able to peel the strands apart + + align:start position:0% +you're able to peel the strands apart + + + align:start position:0% +you're able to peel the strands apart +without breaking the bonds the calent + + align:start position:0% +without breaking the bonds the calent + + + align:start position:0% +without breaking the bonds the calent +bonds and then by pairing a with T and G + + align:start position:0% +bonds and then by pairing a with T and G + + + align:start position:0% +bonds and then by pairing a with T and G +with c and doing that on both strings + + align:start position:0% +with c and doing that on both strings + + + align:start position:0% +with c and doing that on both strings +then you can end up with two identical + + align:start position:0% +then you can end up with two identical + + + align:start position:0% +then you can end up with two identical +copies and so if you do two identical + + align:start position:0% +copies and so if you do two identical + + + align:start position:0% +copies and so if you do two identical +copies they do it again you get eight + + align:start position:0% +copies they do it again you get eight + + + align:start position:0% +copies they do it again you get eight +one of the things we've we've realized + + align:start position:0% +one of the things we've we've realized + + + align:start position:0% +one of the things we've we've realized +over the last few last two or three + + align:start position:0% +over the last few last two or three + + + align:start position:0% +over the last few last two or three +years in looking through the exams is + + align:start position:0% +years in looking through the exams is + + + align:start position:0% +years in looking through the exams is +somehow at least some of the class + + align:start position:0% +somehow at least some of the class + + + align:start position:0% +somehow at least some of the class +didn't connect the business about cells + + align:start position:0% +didn't connect the business about cells + + + align:start position:0% +didn't connect the business about cells +coming from other cells and DNA + + align:start position:0% +coming from other cells and DNA + + + align:start position:0% +coming from other cells and DNA +duplicating to give daughter DNA and I'm + + align:start position:0% +duplicating to give daughter DNA and I'm + + + align:start position:0% +duplicating to give daughter DNA and I'm +just trying to hammer home the point the + + align:start position:0% +just trying to hammer home the point the + + + align:start position:0% +just trying to hammer home the point the +these are related every time a cell + + align:start position:0% +these are related every time a cell + + + align:start position:0% +these are related every time a cell +divides it has to duplicate it genetic + + align:start position:0% +divides it has to duplicate it genetic + + + align:start position:0% +divides it has to duplicate it genetic +information that's why I'm going to be + + align:start position:0% +information that's why I'm going to be + + + align:start position:0% +information that's why I'm going to be +telling you about DNA replication here's + + align:start position:0% +telling you about DNA replication here's + + + align:start position:0% +telling you about DNA replication here's +a picture of that same cancer cell but + + align:start position:0% +a picture of that same cancer cell but + + + align:start position:0% +a picture of that same cancer cell but +watch over here this is the DNA and you + + align:start position:0% +watch over here this is the DNA and you + + + align:start position:0% +watch over here this is the DNA and you +see it's doubled and see how the the DNA + + align:start position:0% +see it's doubled and see how the the DNA + + + align:start position:0% +see it's doubled and see how the the DNA +which is in chromosomes has pulled apart + + align:start position:0% +which is in chromosomes has pulled apart + + + align:start position:0% +which is in chromosomes has pulled apart +so that at the end you now have two + + align:start position:0% +so that at the end you now have two + + + align:start position:0% +so that at the end you now have two +cells and you've got identical copies of + + align:start position:0% +cells and you've got identical copies of + + + align:start position:0% +cells and you've got identical copies of +of DNA so if you're studying cancer for + + align:start position:0% +of DNA so if you're studying cancer for + + + align:start position:0% +of DNA so if you're studying cancer for +example there's this this sort of thing + + align:start position:0% +example there's this this sort of thing + + + align:start position:0% +example there's this this sort of thing +is relevant to + + align:start position:0% +is relevant to + + + align:start position:0% +is relevant to +you okay so um the issue of how oh + + align:start position:0% +you okay so um the issue of how oh + + + align:start position:0% +you okay so um the issue of how oh +before I do that sorry just a couple of + + align:start position:0% +before I do that sorry just a couple of + + + align:start position:0% +before I do that sorry just a couple of +things about DNA replication before I + + align:start position:0% +things about DNA replication before I + + + align:start position:0% +things about DNA replication before I +dive into this so we all started as a + + align:start position:0% +dive into this so we all started as a + + + align:start position:0% +dive into this so we all started as a +single + + align:start position:0% +single + + + align:start position:0% +single +cell uh I've got a lot more obviously + + align:start position:0% +cell uh I've got a lot more obviously + + + align:start position:0% +cell uh I've got a lot more obviously +because I'm made up of a lot of + + align:start position:0% +because I'm made up of a lot of + + + align:start position:0% +because I'm made up of a lot of +cells if I took all the DNA in my body + + align:start position:0% +cells if I took all the DNA in my body + + + align:start position:0% +cells if I took all the DNA in my body +and I lined up all the molecules in + + align:start position:0% +and I lined up all the molecules in + + + align:start position:0% +and I lined up all the molecules in +it you guys any got any idea how long + + align:start position:0% +it you guys any got any idea how long + + + align:start position:0% +it you guys any got any idea how long +that would + + align:start position:0% +that would + + + align:start position:0% +that would +be who thinks it would reach let's say + + align:start position:0% +be who thinks it would reach let's say + + + align:start position:0% +be who thinks it would reach let's say +across the room + + align:start position:0% + + + + align:start position:0% + +okay choss + + align:start position:0% +okay choss + + + align:start position:0% +okay choss +campus chross + + align:start position:0% + + + + align:start position:0% + +Cambridge round round the + + align:start position:0% +Cambridge round round the + + + align:start position:0% +Cambridge round round the +world to the + + align:start position:0% +world to the + + + align:start position:0% +world to the +Moon anybody left to the + + align:start position:0% + + + + align:start position:0% + +sun I got 10 to the 14 cells there's + + align:start position:0% +sun I got 10 to the 14 cells there's + + + align:start position:0% +sun I got 10 to the 14 cells there's +about meter two in each cell 10 to 20 + + align:start position:0% +about meter two in each cell 10 to 20 + + + align:start position:0% +about meter two in each cell 10 to 20 +billion miles of + + align:start position:0% +billion miles of + + + align:start position:0% +billion miles of +DNA in each of our bodies human DNA they + + align:start position:0% +DNA in each of our bodies human DNA they + + + align:start position:0% +DNA in each of our bodies human DNA they +would go back and forth to the sun + + align:start position:0% +would go back and forth to the sun + + + align:start position:0% +would go back and forth to the sun +multiple times so that much DNA had to + + align:start position:0% +multiple times so that much DNA had to + + + align:start position:0% +multiple times so that much DNA had to +get + + align:start position:0% +get + + + align:start position:0% +get +replicated in order for the fertilized + + align:start position:0% +replicated in order for the fertilized + + + align:start position:0% +replicated in order for the fertilized +EG we all started it as to become + + align:start position:0% +EG we all started it as to become + + + align:start position:0% +EG we all started it as to become +you another thing the accuracy of + + align:start position:0% +you another thing the accuracy of + + + align:start position:0% +you another thing the accuracy of +replication is about 10 Theus + + align:start position:0% + + + + align:start position:0% + +10th most people including myself don't + + align:start position:0% +10th most people including myself don't + + + align:start position:0% +10th most people including myself don't +have a very good feel for exponents so + + align:start position:0% +have a very good feel for exponents so + + + align:start position:0% +have a very good feel for exponents so +that's one mistake in 10 billion + + align:start position:0% +that's one mistake in 10 billion + + + align:start position:0% +that's one mistake in 10 billion +can we you know could be one mistake in + + align:start position:0% +can we you know could be one mistake in + + + align:start position:0% +can we you know could be one mistake in +10 to the 99th what does one mistake in + + align:start position:0% +10 to the 99th what does one mistake in + + + align:start position:0% +10 to the 99th what does one mistake in +10 billion mean so it is uh let's relate + + align:start position:0% +10 billion mean so it is uh let's relate + + + align:start position:0% +10 billion mean so it is uh let's relate +it to something we know if I was + + align:start position:0% +it to something we know if I was + + + align:start position:0% +it to something we know if I was +typing let's say eight-letter words 60 + + align:start position:0% +typing let's say eight-letter words 60 + + + align:start position:0% +typing let's say eight-letter words 60 +words a + + align:start position:0% +words a + + + align:start position:0% +words a +minute 24 hours a day 7 days a week and + + align:start position:0% +minute 24 hours a day 7 days a week and + + + align:start position:0% +minute 24 hours a day 7 days a week and +I was as good as DNA + + align:start position:0% +I was as good as DNA + + + align:start position:0% +I was as good as DNA +replication how often would I make a + + align:start position:0% +replication how often would I make a + + + align:start position:0% +replication how often would I make a +mistake so you can each think of how + + align:start position:0% +mistake so you can each think of how + + + align:start position:0% +mistake so you can each think of how +long you think that is but if I was good + + align:start position:0% +long you think that is but if I was good + + + align:start position:0% +long you think that is but if I was good +at that on on average I would make a + + align:start position:0% +at that on on average I would make a + + + align:start position:0% +at that on on average I would make a +mistake once every 38 + + align:start position:0% +mistake once every 38 + + + align:start position:0% +mistake once every 38 +years so I'm about to tell you about a + + align:start position:0% +years so I'm about to tell you about a + + + align:start position:0% +years so I'm about to tell you about a +process that's absolutely astonishing in + + align:start position:0% +process that's absolutely astonishing in + + + align:start position:0% +process that's absolutely astonishing in +terms of how you know how fast and how + + align:start position:0% +terms of how you know how fast and how + + + align:start position:0% +terms of how you know how fast and how +much you can do and with an accuracy + + align:start position:0% +much you can do and with an accuracy + + + align:start position:0% +much you can do and with an accuracy +that goes beyond what we're used to in + + align:start position:0% +that goes beyond what we're used to in + + + align:start position:0% +that goes beyond what we're used to in +our our ordinary ordinary life so how + + align:start position:0% +our our ordinary ordinary life so how + + + align:start position:0% +our our ordinary ordinary life so how +does it do this it has to be more than + + align:start position:0% +does it do this it has to be more than + + + align:start position:0% +does it do this it has to be more than +just pulling the the strands apart and + + align:start position:0% +just pulling the the strands apart and + + + align:start position:0% +just pulling the the strands apart and +there's been some confusion as to why + + align:start position:0% +there's been some confusion as to why + + + align:start position:0% +there's been some confusion as to why +I'm emphasizing 5 Prime and 3 Prime well + + align:start position:0% +I'm emphasizing 5 Prime and 3 Prime well + + + align:start position:0% +I'm emphasizing 5 Prime and 3 Prime well +each of these subunits each + + align:start position:0% +each of these subunits each + + + align:start position:0% +each of these subunits each +nucleotide this is a thre Prime + + align:start position:0% +nucleotide this is a thre Prime + + + align:start position:0% +nucleotide this is a thre Prime +hydroxy this is the five Prime position + + align:start position:0% +hydroxy this is the five Prime position + + + align:start position:0% +hydroxy this is the five Prime position +if we were joining together subunits + + align:start position:0% +if we were joining together subunits + + + align:start position:0% +if we were joining together subunits +that had a hook and an eye it would make + + align:start position:0% +that had a hook and an eye it would make + + + align:start position:0% +that had a hook and an eye it would make +a difference because it's not the same + + align:start position:0% +a difference because it's not the same + + + align:start position:0% +a difference because it's not the same +on both ends if we're going to start + + align:start position:0% +on both ends if we're going to start + + + align:start position:0% +on both ends if we're going to start +hooking together it's it's exactly the + + align:start position:0% +hooking together it's it's exactly the + + + align:start position:0% +hooking together it's it's exactly the +same thing when we get to a biochemical + + align:start position:0% +same thing when we get to a biochemical + + + align:start position:0% +same thing when we get to a biochemical +level hydroxy the five Prime n is not + + align:start position:0% +level hydroxy the five Prime n is not + + + align:start position:0% +level hydroxy the five Prime n is not +the same as hydroxy the three prime in + + align:start position:0% +the same as hydroxy the three prime in + + + align:start position:0% +the same as hydroxy the three prime in +because the it's an asymmetric um the + + align:start position:0% +because the it's an asymmetric um the + + + align:start position:0% +because the it's an asymmetric um the +whole thing is is asymmetric so uh + + align:start position:0% + + + + align:start position:0% + +the enzymes that copy + + align:start position:0% +the enzymes that copy + + + align:start position:0% +the enzymes that copy +DNA are known as as DNA U + + align:start position:0% +DNA are known as as DNA U + + + align:start position:0% +DNA are known as as DNA U +polymerases and it was very difficult + + align:start position:0% +polymerases and it was very difficult + + + align:start position:0% +polymerases and it was very difficult +challenge to uh figure out how they um + + align:start position:0% +challenge to uh figure out how they um + + + align:start position:0% +challenge to uh figure out how they um +how how they operated but Arthur + + align:start position:0% +how how they operated but Arthur + + + align:start position:0% +how how they operated but Arthur +cornberg + + align:start position:0% +cornberg + + + align:start position:0% +cornberg +was the P first person to solve this + + align:start position:0% +was the P first person to solve this + + + align:start position:0% +was the P first person to solve this +problem he was an EXT + + align:start position:0% +problem he was an EXT + + + align:start position:0% +problem he was an EXT +extraordinarily gifted biochemist he's + + align:start position:0% +extraordinarily gifted biochemist he's + + + align:start position:0% +extraordinarily gifted biochemist he's +still at uh he's still at uh Stanford + + align:start position:0% +still at uh he's still at uh Stanford + + + align:start position:0% +still at uh he's still at uh Stanford +and what he found was I'm if we have a + + align:start position:0% +and what he found was I'm if we have a + + + align:start position:0% +and what he found was I'm if we have a +five Prime end this would then be the + + align:start position:0% +five Prime end this would then be the + + + align:start position:0% +five Prime end this would then be the +three prime end and there's a three + + align:start position:0% +three prime end and there's a three + + + align:start position:0% +three prime end and there's a three +prime hydroxy which is this one right + + align:start position:0% +prime hydroxy which is this one right + + + align:start position:0% +prime hydroxy which is this one right +here and this was paired say with a c + + align:start position:0% +here and this was paired say with a c + + + align:start position:0% +here and this was paired say with a c +and an a paired with a uh + + align:start position:0% +and an a paired with a uh + + + align:start position:0% +and an a paired with a uh +a t and let's say a g paired with a a c + + align:start position:0% +a t and let's say a g paired with a a c + + + align:start position:0% +a t and let's say a g paired with a a c +here and let's say the next template + + align:start position:0% +here and let's say the next template + + + align:start position:0% +here and let's say the next template +base + + align:start position:0% +base + + + align:start position:0% +base +was uh let's make it a + + align:start position:0% +was uh let's make it a + + + align:start position:0% +was uh let's make it a +t what Arthur cornberg was able to find + + align:start position:0% +t what Arthur cornberg was able to find + + + align:start position:0% +t what Arthur cornberg was able to find +was an enzyme activity that catalyzed a + + align:start position:0% +was an enzyme activity that catalyzed a + + + align:start position:0% +was an enzyme activity that catalyzed a +template + + align:start position:0% +template + + + align:start position:0% +template +dependent replication of DNA that was + + align:start position:0% +dependent replication of DNA that was + + + align:start position:0% +dependent replication of DNA that was +critical because he had to find + + align:start position:0% +critical because he had to find + + + align:start position:0% +critical because he had to find +somewhere if he broke the cells open + + align:start position:0% +somewhere if he broke the cells open + + + align:start position:0% +somewhere if he broke the cells open +somewhere in that Commish + + align:start position:0% +somewhere in that Commish + + + align:start position:0% +somewhere in that Commish +of uh enzymes and and things from inside + + align:start position:0% +of uh enzymes and and things from inside + + + align:start position:0% +of uh enzymes and and things from inside +a cell there had to be something that + + align:start position:0% +a cell there had to be something that + + + align:start position:0% +a cell there had to be something that +was able to copy DNA so in order to do + + align:start position:0% +was able to copy DNA so in order to do + + + align:start position:0% +was able to copy DNA so in order to do +that he had to work out an assay and he + + align:start position:0% +that he had to work out an assay and he + + + align:start position:0% +that he had to work out an assay and he +also had to have some kind of guess as + + align:start position:0% +also had to have some kind of guess as + + + align:start position:0% +also had to have some kind of guess as +to what the the cell would be using in + + align:start position:0% +to what the the cell would be using in + + + align:start position:0% +to what the the cell would be using in +order to carry out the synthesis well + + align:start position:0% +order to carry out the synthesis well + + + align:start position:0% +order to carry out the synthesis well +one thing was sort of obvious was a was + + align:start position:0% +one thing was sort of obvious was a was + + + align:start position:0% +one thing was sort of obvious was a was +a DNA template because that was being + + align:start position:0% +a DNA template because that was being + + + align:start position:0% +a DNA template because that was being +copied but the other part was you had to + + align:start position:0% +copied but the other part was you had to + + + align:start position:0% +copied but the other part was you had to +have energy to form a Cove valent Bond + + align:start position:0% +have energy to form a Cove valent Bond + + + align:start position:0% +have energy to form a Cove valent Bond +Bond so somehow there had to be + + align:start position:0% +Bond so somehow there had to be + + + align:start position:0% +Bond so somehow there had to be +something that was sort of activated + + align:start position:0% +something that was sort of activated + + + align:start position:0% +something that was sort of activated +with the energy built into the molecule + + align:start position:0% +with the energy built into the molecule + + + align:start position:0% +with the energy built into the molecule +so that thermodynamically the whole + + align:start position:0% +so that thermodynamically the whole + + + align:start position:0% +so that thermodynamically the whole +thing would slide downhill when you made + + align:start position:0% +thing would slide downhill when you made + + + align:start position:0% +thing would slide downhill when you made +a when you made a bond and he knew that + + align:start position:0% +a when you made a bond and he knew that + + + align:start position:0% +a when you made a bond and he knew that +the cell + + align:start position:0% +the cell + + + align:start position:0% +the cell +had triphosphates just the same type + + align:start position:0% +had triphosphates just the same type + + + align:start position:0% +had triphosphates just the same type +that we talked about with when we talked + + align:start position:0% +that we talked about with when we talked + + + align:start position:0% +that we talked about with when we talked +about + + align:start position:0% + + + + align:start position:0% + +ATP + + align:start position:0% + + + + align:start position:0% + +so this would + + align:start position:0% + + + + align:start position:0% + +be a deoxy Riu uh + + align:start position:0% + + + + align:start position:0% + +nucleotide + + align:start position:0% + + + + align:start position:0% + +triphosphate and he was able to uh make + + align:start position:0% +triphosphate and he was able to uh make + + + align:start position:0% +triphosphate and he was able to uh make +a guess cuz he had to try things until + + align:start position:0% +a guess cuz he had to try things until + + + align:start position:0% +a guess cuz he had to try things until +he found something was work that would + + align:start position:0% +he found something was work that would + + + align:start position:0% +he found something was work that would +work that this was what's used in DNA + + align:start position:0% +work that this was what's used in DNA + + + align:start position:0% +work that this was what's used in DNA +synthesis so this + + align:start position:0% +synthesis so this + + + align:start position:0% +synthesis so this +hydroxy ultimately attacks this uh + + align:start position:0% +hydroxy ultimately attacks this uh + + + align:start position:0% +hydroxy ultimately attacks this uh +phosphate here and these two other + + align:start position:0% +phosphate here and these two other + + + align:start position:0% +phosphate here and these two other +phosphates then come off as a as a + + align:start position:0% +phosphates then come off as a as a + + + align:start position:0% +phosphates then come off as a as a +leaving group so if we thought of it as + + align:start position:0% +leaving group so if we thought of it as + + + align:start position:0% +leaving group so if we thought of it as +a a + + align:start position:0% +a a + + + align:start position:0% +a a +p like this with two more PS here these + + align:start position:0% +p like this with two more PS here these + + + align:start position:0% +p like this with two more PS here these +two come off and you get a a new bond + + align:start position:0% +two come off and you get a a new bond + + + align:start position:0% +two come off and you get a a new bond +form + + align:start position:0% +form + + + align:start position:0% +form +to + + align:start position:0% +to + + + align:start position:0% +to +the to the phosphate and so what + + align:start position:0% +the to the phosphate and so what + + + align:start position:0% +the to the phosphate and so what +cornberg then was able to find by using + + align:start position:0% +cornberg then was able to find by using + + + align:start position:0% +cornberg then was able to find by using +a DNA template that had this sort + + align:start position:0% + + + + align:start position:0% + +of structure + + align:start position:0% +of structure + + + align:start position:0% +of structure +and PP + + align:start position:0% + + + + align:start position:0% + +p a like this that he was now able to + + align:start position:0% +p a like this that he was now able to + + + align:start position:0% +p a like this that he was now able to +get an A added here here this new this + + align:start position:0% +get an A added here here this new this + + + align:start position:0% +get an A added here here this new this +hydroxy here became the new uh hydroxy + + align:start position:0% +hydroxy here became the new uh hydroxy + + + align:start position:0% +hydroxy here became the new uh hydroxy +and so the the the direction of + + align:start position:0% +and so the the the direction of + + + align:start position:0% +and so the the the direction of +synthesis this strand is the other way + + align:start position:0% +synthesis this strand is the other way + + + align:start position:0% +synthesis this strand is the other way +so the direction of + + align:start position:0% +so the direction of + + + align:start position:0% +so the direction of +synthesis of a DNA polymerize polymerase + + align:start position:0% +synthesis of a DNA polymerize polymerase + + + align:start position:0% +synthesis of a DNA polymerize polymerase +it's polymerizing in the five Prime to 2 + + align:start position:0% +it's polymerizing in the five Prime to 2 + + + align:start position:0% +it's polymerizing in the five Prime to 2 +three prime Direction This was again an + + align:start position:0% +three prime Direction This was again an + + + align:start position:0% +three prime Direction This was again an +amazing Discovery because it was the + + align:start position:0% +amazing Discovery because it was the + + + align:start position:0% +amazing Discovery because it was the +first time that anyone had found an + + align:start position:0% +first time that anyone had found an + + + align:start position:0% +first time that anyone had found an +enzyme that could copy copy DNA Arthur + + align:start position:0% +enzyme that could copy copy DNA Arthur + + + align:start position:0% +enzyme that could copy copy DNA Arthur +cornberg got a Nobel Prize for it but at + + align:start position:0% +cornberg got a Nobel Prize for it but at + + + align:start position:0% +cornberg got a Nobel Prize for it but at +this point um actually genetics came in + + align:start position:0% +this point um actually genetics came in + + + align:start position:0% +this point um actually genetics came in +because there was a scientist John Karn + + align:start position:0% +because there was a scientist John Karn + + + align:start position:0% +because there was a scientist John Karn +who was at that point down in Cold + + align:start position:0% +who was at that point down in Cold + + + align:start position:0% +who was at that point down in Cold +Spring Harbor they told you the other + + align:start position:0% +Spring Harbor they told you the other + + + align:start position:0% +Spring Harbor they told you the other +day and uh John didn't think that in + + align:start position:0% +day and uh John didn't think that in + + + align:start position:0% +day and uh John didn't think that in +spite of the fact that uh Arthur had + + align:start position:0% +spite of the fact that uh Arthur had + + + align:start position:0% +spite of the fact that uh Arthur had +found a DN a DNA plase that had all the + + align:start position:0% +found a DN a DNA plase that had all the + + + align:start position:0% +found a DN a DNA plase that had all the +properties that you'd expect for copying + + align:start position:0% +properties that you'd expect for copying + + + align:start position:0% +properties that you'd expect for copying +uh DNA he didn't think that was the the + + align:start position:0% +uh DNA he didn't think that was the the + + + align:start position:0% +uh DNA he didn't think that was the the +one that actually copied the DNA + + align:start position:0% +one that actually copied the DNA + + + align:start position:0% +one that actually copied the DNA +necessary for cellular replication so he + + align:start position:0% +necessary for cellular replication so he + + + align:start position:0% +necessary for cellular replication so he +reasoned if he was right he'd be able to + + align:start position:0% +reasoned if he was right he'd be able to + + + align:start position:0% +reasoned if he was right he'd be able to +find a mutation that would eliminate the + + align:start position:0% +find a mutation that would eliminate the + + + align:start position:0% +find a mutation that would eliminate the +activity of that enzyme in the cell + + align:start position:0% +activity of that enzyme in the cell + + + align:start position:0% +activity of that enzyme in the cell +would still live and so they did a + + align:start position:0% +would still live and so they did a + + + align:start position:0% +would still live and so they did a +screening and they was a lot of work but + + align:start position:0% +screening and they was a lot of work but + + + align:start position:0% +screening and they was a lot of work but +they eventually found a mutant of ecoli + + align:start position:0% +they eventually found a mutant of ecoli + + + align:start position:0% +they eventually found a mutant of ecoli +that lacked this DNA polymerase that + + align:start position:0% +that lacked this DNA polymerase that + + + align:start position:0% +that lacked this DNA polymerase that +Arthur cornberg discovered and the Stell + + align:start position:0% +Arthur cornberg discovered and the Stell + + + align:start position:0% +Arthur cornberg discovered and the Stell +was still alive was still replicating + + align:start position:0% +was still alive was still replicating + + + align:start position:0% +was still alive was still replicating +its DNA so it told both John and then + + align:start position:0% +its DNA so it told both John and then + + + align:start position:0% +its DNA so it told both John and then +Arthur there must be another enzyme in + + align:start position:0% +Arthur there must be another enzyme in + + + align:start position:0% +Arthur there must be another enzyme in +the cell and so Arthur went back and now + + align:start position:0% +the cell and so Arthur went back and now + + + align:start position:0% +the cell and so Arthur went back and now +working in a mutant that was missing + + align:start position:0% +working in a mutant that was missing + + + align:start position:0% +working in a mutant that was missing +this first plase he discovered he found + + align:start position:0% +this first plase he discovered he found + + + align:start position:0% +this first plase he discovered he found +the one that really replicates the DNA + + align:start position:0% +the one that really replicates the DNA + + + align:start position:0% +the one that really replicates the DNA +the first one's important too it's + + align:start position:0% +the first one's important too it's + + + align:start position:0% +the first one's important too it's +needed for DNA repair I'm going to talk + + align:start position:0% +needed for DNA repair I'm going to talk + + + align:start position:0% +needed for DNA repair I'm going to talk +to you about that in next lecture but + + align:start position:0% +to you about that in next lecture but + + + align:start position:0% +to you about that in next lecture but +it's not absolutely crucial for life and + + align:start position:0% +it's not absolutely crucial for life and + + + align:start position:0% +it's not absolutely crucial for life and +there's an interplay of genetics and + + align:start position:0% +there's an interplay of genetics and + + + align:start position:0% +there's an interplay of genetics and +biochemistry and you'll see I'm just + + align:start position:0% +biochemistry and you'll see I'm just + + + align:start position:0% +biochemistry and you'll see I'm just +sort of foreshadowing what we're going + + align:start position:0% +sort of foreshadowing what we're going + + + align:start position:0% +sort of foreshadowing what we're going +to get to when we talk about the + + align:start position:0% +to get to when we talk about the + + + align:start position:0% +to get to when we talk about the +genetics uh of this and I know a couple + + align:start position:0% +genetics uh of this and I know a couple + + + align:start position:0% +genetics uh of this and I know a couple +of you clearly were frustrated about me + + align:start position:0% +of you clearly were frustrated about me + + + align:start position:0% +of you clearly were frustrated about me +showing you pictures of the people who + + align:start position:0% +showing you pictures of the people who + + + align:start position:0% +showing you pictures of the people who +did this but nevertheless since this was + + align:start position:0% +did this but nevertheless since this was + + + align:start position:0% +did this but nevertheless since this was +such a historic event a couple of years + + align:start position:0% +such a historic event a couple of years + + + align:start position:0% +such a historic event a couple of years +ago uh at Cold Spring Harbor this you + + align:start position:0% +ago uh at Cold Spring Harbor this you + + + align:start position:0% +ago uh at Cold Spring Harbor this you +see the the Helix model down there there + + align:start position:0% +see the the Helix model down there there + + + align:start position:0% +see the the Helix model down there there +was Jim Watson opening the Symposium + + align:start position:0% +was Jim Watson opening the Symposium + + + align:start position:0% +was Jim Watson opening the Symposium +when I got up to talk I said well I'm + + align:start position:0% +when I got up to talk I said well I'm + + + align:start position:0% +when I got up to talk I said well I'm +going to take I told my students I'd let + + align:start position:0% +going to take I told my students I'd let + + + align:start position:0% +going to take I told my students I'd let +them know what it was like when it was + + align:start position:0% +them know what it was like when it was + + + align:start position:0% +them know what it was like when it was +there so I took out a camera and I took + + align:start position:0% +there so I took out a camera and I took + + + align:start position:0% +there so I took out a camera and I took +a picture of the audience and so there + + align:start position:0% +a picture of the audience and so there + + + align:start position:0% +a picture of the audience and so there +are a bunch of Nobel laurates and types + + align:start position:0% +are a bunch of Nobel laurates and types + + + align:start position:0% +are a bunch of Nobel laurates and types +here who are sitting there smiling for + + align:start position:0% +here who are sitting there smiling for + + + align:start position:0% +here who are sitting there smiling for +you guys in in the and there was Arthur + + align:start position:0% +you guys in in the and there was Arthur + + + align:start position:0% +you guys in in the and there was Arthur +cornberg giving his talk now + + align:start position:0% +cornberg giving his talk now + + + align:start position:0% +cornberg giving his talk now +um these DNA U plases are incredible + + align:start position:0% +um these DNA U plases are incredible + + + align:start position:0% +um these DNA U plases are incredible +protein machines the crystal structures + + align:start position:0% +protein machines the crystal structures + + + align:start position:0% +protein machines the crystal structures +of a DNA plase operating plases + + align:start position:0% +of a DNA plase operating plases + + + align:start position:0% +of a DNA plase operating plases +operating their template have been + + align:start position:0% +operating their template have been + + + align:start position:0% +operating their template have been +solved and you can solve depending on + + align:start position:0% +solved and you can solve depending on + + + align:start position:0% +solved and you can solve depending on +how many diffractions you can get you + + align:start position:0% +how many diffractions you can get you + + + align:start position:0% +how many diffractions you can get you +can get a model that's more or more + + align:start position:0% +can get a model that's more or more + + + align:start position:0% +can get a model that's more or more +detailed and there have been some very + + align:start position:0% +detailed and there have been some very + + + align:start position:0% +detailed and there have been some very +high resolution models of DNA plases + + align:start position:0% +high resolution models of DNA plases + + + align:start position:0% +high resolution models of DNA plases +this blue and white stuff is the surface + + align:start position:0% +this blue and white stuff is the surface + + + align:start position:0% +this blue and white stuff is the surface +of the protein and this is sort of the + + align:start position:0% +of the protein and this is sort of the + + + align:start position:0% +of the protein and this is sort of the +template and the and the the various + + align:start position:0% +template and the and the the various + + + align:start position:0% +template and the and the the various +parts I'm just uh to give you an idea + + align:start position:0% +parts I'm just uh to give you an idea + + + align:start position:0% +parts I'm just uh to give you an idea +here these tracings of the of the shapes + + align:start position:0% +here these tracings of the of the shapes + + + align:start position:0% +here these tracings of the of the shapes +of the the electron density and you can + + align:start position:0% +of the the electron density and you can + + + align:start position:0% +of the the electron density and you can +see how the crystallographers have fit + + align:start position:0% +see how the crystallographers have fit + + + align:start position:0% +see how the crystallographers have fit +the + + align:start position:0% +the + + + align:start position:0% +the +nucleotides uh into these uh in the + + align:start position:0% +nucleotides uh into these uh in the + + + align:start position:0% +nucleotides uh into these uh in the +right in the right in the crystal into + + align:start position:0% +right in the right in the crystal into + + + align:start position:0% +right in the right in the crystal into +these electron densities and here + + align:start position:0% +these electron densities and here + + + align:start position:0% +these electron densities and here +putting it together a bit is in the blue + + align:start position:0% +putting it together a bit is in the blue + + + align:start position:0% +putting it together a bit is in the blue +is the secondary structure of the + + align:start position:0% +is the secondary structure of the + + + align:start position:0% +is the secondary structure of the +protein and and the templates and + + align:start position:0% +protein and and the templates and + + + align:start position:0% +protein and and the templates and +whatnot and I don't expect you see very + + align:start position:0% +whatnot and I don't expect you see very + + + align:start position:0% +whatnot and I don't expect you see very +much in that but the point I want to + + align:start position:0% +much in that but the point I want to + + + align:start position:0% +much in that but the point I want to +tell you I want to sort of just set you + + align:start position:0% +tell you I want to sort of just set you + + + align:start position:0% +tell you I want to sort of just set you +up to show you this little movie because + + align:start position:0% +up to show you this little movie because + + + align:start position:0% +up to show you this little movie because +this is an DNA polymerase is a + + align:start position:0% +this is an DNA polymerase is a + + + align:start position:0% +this is an DNA polymerase is a +incredible machines they copy at about a + + align:start position:0% +incredible machines they copy at about a + + + align:start position:0% +incredible machines they copy at about a +thousand nucleotides a second and their + + align:start position:0% +thousand nucleotides a second and their + + + align:start position:0% +thousand nucleotides a second and their +accuracy is is really amazing and I'll + + align:start position:0% +accuracy is is really amazing and I'll + + + align:start position:0% +accuracy is is really amazing and I'll +tell you all the tricks to the accuracy + + align:start position:0% +tell you all the tricks to the accuracy + + + align:start position:0% +tell you all the tricks to the accuracy +in the next lecture but I want to show + + align:start position:0% +in the next lecture but I want to show + + + align:start position:0% +in the next lecture but I want to show +you this little movie because it this is + + align:start position:0% +you this little movie because it this is + + + align:start position:0% +you this little movie because it this is +a a little s sort of a simulation of + + align:start position:0% +a a little s sort of a simulation of + + + align:start position:0% +a a little s sort of a simulation of +what must happen every time a nucleotide + + align:start position:0% +what must happen every time a nucleotide + + + align:start position:0% +what must happen every time a nucleotide +is added now the yellow here is the + + align:start position:0% +is added now the yellow here is the + + + align:start position:0% +is added now the yellow here is the +we'll see this over and over again so uh + + align:start position:0% +we'll see this over and over again so uh + + + align:start position:0% +we'll see this over and over again so uh +I'll take it in pieces the yellow and + + align:start position:0% +I'll take it in pieces the yellow and + + + align:start position:0% +I'll take it in pieces the yellow and +the orange are the are the secondary + + align:start position:0% +the orange are the are the secondary + + + align:start position:0% +the orange are the are the secondary +structures that's an alpha Helix and + + align:start position:0% +structures that's an alpha Helix and + + + align:start position:0% +structures that's an alpha Helix and +certainly one thing you can see is + + align:start position:0% +certainly one thing you can see is + + + align:start position:0% +certainly one thing you can see is +happening as I'm sure as we're looking + + align:start position:0% +happening as I'm sure as we're looking + + + align:start position:0% +happening as I'm sure as we're looking +at this is this the parts of the protein + + align:start position:0% +at this is this the parts of the protein + + + align:start position:0% +at this is this the parts of the protein +are moving during this you can see this + + align:start position:0% +are moving during this you can see this + + + align:start position:0% +are moving during this you can see this +Alpha Helix is sort of swinging up and + + align:start position:0% +Alpha Helix is sort of swinging up and + + + align:start position:0% +Alpha Helix is sort of swinging up and +Swinging back down now what's what's + + align:start position:0% +Swinging back down now what's what's + + + align:start position:0% +Swinging back down now what's what's +over here is the over on this over here + + align:start position:0% +over here is the over on this over here + + + align:start position:0% +over here is the over on this over here +is the template base that's the base + + align:start position:0% +is the template base that's the base + + + align:start position:0% +is the template base that's the base +that's that corresponds to the T that I + + align:start position:0% +that's that corresponds to the T that I + + + align:start position:0% +that's that corresponds to the T that I +was just showing you here this is the + + align:start position:0% +was just showing you here this is the + + + align:start position:0% +was just showing you here this is the +incoming nucleotide there is the + + align:start position:0% +incoming nucleotide there is the + + + align:start position:0% +incoming nucleotide there is the +triphosphate coming down here and in + + align:start position:0% +triphosphate coming down here and in + + + align:start position:0% +triphosphate coming down here and in +fact you just see those two phosphates + + align:start position:0% +fact you just see those two phosphates + + + align:start position:0% +fact you just see those two phosphates +going so what's happening here here this + + align:start position:0% +going so what's happening here here this + + + align:start position:0% +going so what's happening here here this +is going to be the end of the the + + align:start position:0% +is going to be the end of the the + + + align:start position:0% +is going to be the end of the the +growing chain it's going to attack right + + align:start position:0% +growing chain it's going to attack right + + + align:start position:0% +growing chain it's going to attack right +there join the phosphate and the + + align:start position:0% +there join the phosphate and the + + + align:start position:0% +there join the phosphate and the +pyrophosphate will leave and when the if + + align:start position:0% +pyrophosphate will leave and when the if + + + align:start position:0% +pyrophosphate will leave and when the if +you'll take a look when you see this + + align:start position:0% +you'll take a look when you see this + + + align:start position:0% +you'll take a look when you see this +movement of this this Helix from the + + align:start position:0% +movement of this this Helix from the + + + align:start position:0% +movement of this this Helix from the +beginning state to up to here you'll see + + align:start position:0% +beginning state to up to here you'll see + + + align:start position:0% +beginning state to up to here you'll see +what happens is it's squeezing the + + align:start position:0% +what happens is it's squeezing the + + + align:start position:0% +what happens is it's squeezing the +template base and + + align:start position:0% +template base and + + + align:start position:0% +template base and +the uh incoming nucleotide together what + + align:start position:0% +the uh incoming nucleotide together what + + + align:start position:0% +the uh incoming nucleotide together what +it's really doing is testing for the + + align:start position:0% +it's really doing is testing for the + + + align:start position:0% +it's really doing is testing for the +correct shape remember the shape of an + + align:start position:0% +correct shape remember the shape of an + + + align:start position:0% +correct shape remember the shape of an +at base pair and a GC based pair is the + + align:start position:0% +at base pair and a GC based pair is the + + + align:start position:0% +at base pair and a GC based pair is the +same and if those of you who are + + align:start position:0% +same and if those of you who are + + + align:start position:0% +same and if those of you who are +confused about guanine and the keto enol + + align:start position:0% +confused about guanine and the keto enol + + + align:start position:0% +confused about guanine and the keto enol +thing try to draw hydrogen bonds with + + align:start position:0% +thing try to draw hydrogen bonds with + + + align:start position:0% +thing try to draw hydrogen bonds with +the enol form of of guanine and see how + + align:start position:0% +the enol form of of guanine and see how + + + align:start position:0% +the enol form of of guanine and see how +and see how you do I think he'll you'll + + align:start position:0% +and see how you do I think he'll you'll + + + align:start position:0% +and see how you do I think he'll you'll +begin to understand of it so this is one + + align:start position:0% +begin to understand of it so this is one + + + align:start position:0% +begin to understand of it so this is one +of the so at the heart of life is + + align:start position:0% +of the so at the heart of life is + + + align:start position:0% +of the so at the heart of life is +something that can copy DNA and there + + align:start position:0% +something that can copy DNA and there + + + align:start position:0% +something that can copy DNA and there +are these exquisitely beautiful machines + + align:start position:0% +are these exquisitely beautiful machines + + + align:start position:0% +are these exquisitely beautiful machines +uh the replicative machine in in E coli + + align:start position:0% +uh the replicative machine in in E coli + + + align:start position:0% +uh the replicative machine in in E coli +has 18 proteins and the ones and our + + align:start position:0% +has 18 proteins and the ones and our + + + align:start position:0% +has 18 proteins and the ones and our +bodies are even more sophisticated with + + align:start position:0% +bodies are even more sophisticated with + + + align:start position:0% +bodies are even more sophisticated with +even more with more parts + + align:start position:0% +even more with more parts + + + align:start position:0% +even more with more parts +um okay but + + align:start position:0% +um okay but + + + align:start position:0% +um okay but +to to replicate a DNA molecule there's + + align:start position:0% +to to replicate a DNA molecule there's + + + align:start position:0% +to to replicate a DNA molecule there's +an another problem that comes up because + + align:start position:0% +an another problem that comes up because + + + align:start position:0% +an another problem that comes up because +DNA polymerases + + align:start position:0% + + + + align:start position:0% + +copy see grow let's + + align:start position:0% + + + + align:start position:0% + +see grow + + align:start position:0% +see grow + + + align:start position:0% +see grow +chains in a five Prime to three prime + + align:start position:0% + + + + align:start position:0% + +Direction + + align:start position:0% + + + + align:start position:0% + +and they + + align:start position:0% +and they + + + align:start position:0% +and they +need a thre Prime hydroxy + + align:start position:0% + + + + align:start position:0% + +Terminus so they won't work if you just + + align:start position:0% +Terminus so they won't work if you just + + + align:start position:0% +Terminus so they won't work if you just +gave it a single strand of of + + align:start position:0% +gave it a single strand of of + + + align:start position:0% +gave it a single strand of of +DNA no DNA polymerase can handle that it + + align:start position:0% +DNA no DNA polymerase can handle that it + + + align:start position:0% +DNA no DNA polymerase can handle that it +has to have something like this where + + align:start position:0% +has to have something like this where + + + align:start position:0% +has to have something like this where +there's a template + + align:start position:0% +there's a template + + + align:start position:0% +there's a template +strand + + align:start position:0% + + + + align:start position:0% + +and there's what's known as the primer + + align:start position:0% +and there's what's known as the primer + + + align:start position:0% +and there's what's known as the primer +strand so there has to be something that + + align:start position:0% +strand so there has to be something that + + + align:start position:0% +strand so there has to be something that +has the three prime hydroxy and there + + align:start position:0% +has the three prime hydroxy and there + + + align:start position:0% +has the three prime hydroxy and there +has to be something that's going to + + align:start position:0% +has to be something that's going to + + + align:start position:0% +has to be something that's going to +provide the template that's going to be + + align:start position:0% +provide the template that's going to be + + + align:start position:0% +provide the template that's going to be +copied so if we pull strands apart like + + align:start position:0% +copied so if we pull strands apart like + + + align:start position:0% +copied so if we pull strands apart like +this with five Prime to 3 Prime then + + align:start position:0% +this with five Prime to 3 Prime then + + + align:start position:0% +this with five Prime to 3 Prime then +this will be five Prime to 3 Prime + + align:start position:0% +this will be five Prime to 3 Prime + + + align:start position:0% +this will be five Prime to 3 Prime +running in the opposite direction + + align:start position:0% +running in the opposite direction + + + align:start position:0% +running in the opposite direction +if we + + align:start position:0% + + + + align:start position:0% + +have uh template like this this is okay + + align:start position:0% +have uh template like this this is okay + + + align:start position:0% +have uh template like this this is okay +because the Strand here can be copied + + align:start position:0% +because the Strand here can be copied + + + align:start position:0% +because the Strand here can be copied +five Prime to three prime + + align:start position:0% +five Prime to three prime + + + align:start position:0% +five Prime to three prime +the this is the New + + align:start position:0% +the this is the New + + + align:start position:0% +the this is the New +Strand being + + align:start position:0% +Strand being + + + align:start position:0% +Strand being +synthesized by the DNA + + align:start position:0% +synthesized by the DNA + + + align:start position:0% +synthesized by the DNA +polymerase but what about the other + + align:start position:0% +polymerase but what about the other + + + align:start position:0% +polymerase but what about the other +strand the replication fork is moving in + + align:start position:0% +strand the replication fork is moving in + + + align:start position:0% +strand the replication fork is moving in +this + + align:start position:0% +this + + + align:start position:0% +this +direction but if the so here is the 3 to + + align:start position:0% +direction but if the so here is the 3 to + + + align:start position:0% +direction but if the so here is the 3 to +five Prime Direction here so if the DNA + + align:start position:0% +five Prime Direction here so if the DNA + + + align:start position:0% +five Prime Direction here so if the DNA +polymerase is going to be copying this + + align:start position:0% +polymerase is going to be copying this + + + align:start position:0% +polymerase is going to be copying this +strand it's going to be moving backwards + + align:start position:0% +strand it's going to be moving backwards + + + align:start position:0% +strand it's going to be moving backwards +to the + + align:start position:0% +to the + + + align:start position:0% +to the +direction of the replication fork now I + + align:start position:0% +direction of the replication fork now I + + + align:start position:0% +direction of the replication fork now I +guess Evolution nature could have + + align:start position:0% +guess Evolution nature could have + + + align:start position:0% +guess Evolution nature could have +selected for two types of DNA + + align:start position:0% +selected for two types of DNA + + + align:start position:0% +selected for two types of DNA +polymerases one that copies 5 Prime to 3 + + align:start position:0% +polymerases one that copies 5 Prime to 3 + + + align:start position:0% +polymerases one that copies 5 Prime to 3 +Prime and one that cop copies in the in + + align:start position:0% +Prime and one that cop copies in the in + + + align:start position:0% +Prime and one that cop copies in the in +the opposite direction but it didn't and + + align:start position:0% +the opposite direction but it didn't and + + + align:start position:0% +the opposite direction but it didn't and +there are a number of theoretical + + align:start position:0% +there are a number of theoretical + + + align:start position:0% +there are a number of theoretical +reasons that we could discuss in more + + align:start position:0% +reasons that we could discuss in more + + + align:start position:0% +reasons that we could discuss in more +advanced course perhaps for why that's + + align:start position:0% +advanced course perhaps for why that's + + + align:start position:0% +advanced course perhaps for why that's +true but in fact what it does is it uses + + align:start position:0% +true but in fact what it does is it uses + + + align:start position:0% +true but in fact what it does is it uses +the same pimas so as these things peel + + align:start position:0% +the same pimas so as these things peel + + + align:start position:0% +the same pimas so as these things peel +apart the plas works in the other + + align:start position:0% +apart the plas works in the other + + + align:start position:0% +apart the plas works in the other +direction but there's another problem + + align:start position:0% +direction but there's another problem + + + align:start position:0% +direction but there's another problem +there's no if I just peel it apart like + + align:start position:0% +there's no if I just peel it apart like + + + align:start position:0% +there's no if I just peel it apart like +this there's no three prime + + align:start position:0% +this there's no three prime + + + align:start position:0% +this there's no three prime +hydroxy so it took people quite a few + + align:start position:0% +hydroxy so it took people quite a few + + + align:start position:0% +hydroxy so it took people quite a few +years to figure fure out the strategy + + align:start position:0% +years to figure fure out the strategy + + + align:start position:0% +years to figure fure out the strategy +that's used in nature nature has a + + align:start position:0% +that's used in nature nature has a + + + align:start position:0% +that's used in nature nature has a +special enzyme that makes a little piece + + align:start position:0% +special enzyme that makes a little piece + + + align:start position:0% +special enzyme that makes a little piece +of + + align:start position:0% + + + + align:start position:0% + +RNA it's called + + align:start position:0% + + + + align:start position:0% + +a an RNA primer what it does is it + + align:start position:0% + + + + align:start position:0% + +provides a three prime + + align:start position:0% +provides a three prime + + + align:start position:0% +provides a three prime +hydroxy and once you have the three + + align:start position:0% +hydroxy and once you have the three + + + align:start position:0% +hydroxy and once you have the three +prime hydroxy at the end of a little RNA + + align:start position:0% +prime hydroxy at the end of a little RNA + + + align:start position:0% +prime hydroxy at the end of a little RNA +chain then the DNA + + align:start position:0% + + + + align:start position:0% + +polymerase can be made five Prime to + + align:start position:0% +polymerase can be made five Prime to + + + align:start position:0% +polymerase can be made five Prime to +three prime so as the as you peel open + + align:start position:0% +three prime so as the as you peel open + + + align:start position:0% +three prime so as the as you peel open +the replication fork then you little + + align:start position:0% +the replication fork then you little + + + align:start position:0% +the replication fork then you little +pieces of of RNA are used to make the a + + align:start position:0% +pieces of of RNA are used to make the a + + + align:start position:0% +pieces of of RNA are used to make the a +new strand of DNA and it goes this this + + align:start position:0% +new strand of DNA and it goes this this + + + align:start position:0% +new strand of DNA and it goes this this +way now that obviously doesn't give you + + align:start position:0% +way now that obviously doesn't give you + + + align:start position:0% +way now that obviously doesn't give you +a new intact DNA strand and the part of + + align:start position:0% +a new intact DNA strand and the part of + + + align:start position:0% +a new intact DNA strand and the part of +the clue to this uh working out what was + + align:start position:0% +the clue to this uh working out what was + + + align:start position:0% +the clue to this uh working out what was +going on at DNA replication was the + + align:start position:0% +going on at DNA replication was the + + + align:start position:0% +going on at DNA replication was the +recognition that newly synthesized DNA + + align:start position:0% +recognition that newly synthesized DNA + + + align:start position:0% +recognition that newly synthesized DNA +was made as little pieces and then later + + align:start position:0% +was made as little pieces and then later + + + align:start position:0% +was made as little pieces and then later +it got joined into longer longer + + align:start position:0% + + + + align:start position:0% + +pieces and the person who discovered + + align:start position:0% +pieces and the person who discovered + + + align:start position:0% +pieces and the person who discovered +this was okazaki so these fragments of + + align:start position:0% +this was okazaki so these fragments of + + + align:start position:0% +this was okazaki so these fragments of +DNA that are synthesized initially are + + align:start position:0% +DNA that are synthesized initially are + + + align:start position:0% +DNA that are synthesized initially are +called okazaki fragments after the the + + align:start position:0% +called okazaki fragments after the the + + + align:start position:0% +called okazaki fragments after the the +person who discovered this it was it was + + align:start position:0% +person who discovered this it was it was + + + align:start position:0% +person who discovered this it was it was +rather puzzling because little when you + + align:start position:0% +rather puzzling because little when you + + + align:start position:0% +rather puzzling because little when you +tried to look at the synthesis of DNA + + align:start position:0% +tried to look at the synthesis of DNA + + + align:start position:0% +tried to look at the synthesis of DNA +you're looking at a long molecule and + + align:start position:0% +you're looking at a long molecule and + + + align:start position:0% +you're looking at a long molecule and +you found some of the newly synthesized + + align:start position:0% +you found some of the newly synthesized + + + align:start position:0% +you found some of the newly synthesized +material was in short pieces and as you + + align:start position:0% +material was in short pieces and as you + + + align:start position:0% +material was in short pieces and as you +watched over time it got uh it got um + + align:start position:0% +watched over time it got uh it got um + + + align:start position:0% +watched over time it got uh it got um +longer so the the cell I think you can + + align:start position:0% +longer so the the cell I think you can + + + align:start position:0% +longer so the the cell I think you can +sort of see from first principles what + + align:start position:0% +sort of see from first principles what + + + align:start position:0% +sort of see from first principles what +has to happen here then that in order + + align:start position:0% +has to happen here then that in order + + + align:start position:0% +has to happen here then that in order +order to come and + + align:start position:0% + + + + align:start position:0% + +make this strand is pretty easy to do + + align:start position:0% +make this strand is pretty easy to do + + + align:start position:0% +make this strand is pretty easy to do +but what the cells have to do now is + + align:start position:0% +but what the cells have to do now is + + + align:start position:0% +but what the cells have to do now is +they put these little RNA + + align:start position:0% + + + + align:start position:0% + +primers and then they remove the + + align:start position:0% +primers and then they remove the + + + align:start position:0% +primers and then they remove the +RNA + + align:start position:0% + + + + align:start position:0% + +by an enzyme that's capable of of + + align:start position:0% +by an enzyme that's capable of of + + + align:start position:0% +by an enzyme that's capable of of +degrading the DNA or clipping it at the + + align:start position:0% +degrading the DNA or clipping it at the + + + align:start position:0% +degrading the DNA or clipping it at the +junction and that then leaves + + align:start position:0% + + + + align:start position:0% + +the cell in this sort of situation where + + align:start position:0% +the cell in this sort of situation where + + + align:start position:0% +the cell in this sort of situation where +there are little tiny gaps in between + + align:start position:0% +there are little tiny gaps in between + + + align:start position:0% +there are little tiny gaps in between +these pieces of DNA but at the end of + + align:start position:0% +these pieces of DNA but at the end of + + + align:start position:0% +these pieces of DNA but at the end of +each one of these is a three prime + + align:start position:0% +each one of these is a three prime + + + align:start position:0% +each one of these is a three prime +hydroxy so another polymerase or some + + align:start position:0% +hydroxy so another polymerase or some + + + align:start position:0% +hydroxy so another polymerase or some +one one or another polymerase in the + + align:start position:0% +one one or another polymerase in the + + + align:start position:0% +one one or another polymerase in the +cell can fill those little pieces of uh + + align:start position:0% +cell can fill those little pieces of uh + + + align:start position:0% +cell can fill those little pieces of uh +of DNA out and then there's one little + + align:start position:0% +of DNA out and then there's one little + + + align:start position:0% +of DNA out and then there's one little +Nick that needs to be need to needs to + + align:start position:0% +Nick that needs to be need to needs to + + + align:start position:0% +Nick that needs to be need to needs to +be sealed and so what you finally end up + + align:start position:0% +be sealed and so what you finally end up + + + align:start position:0% +be sealed and so what you finally end up +with is a a three prime hydroxy here a + + align:start position:0% +with is a a three prime hydroxy here a + + + align:start position:0% +with is a a three prime hydroxy here a +five + + align:start position:0% + + + + align:start position:0% + +Prime + + align:start position:0% +Prime + + + align:start position:0% +Prime +phosphate that's the other end and then + + align:start position:0% +phosphate that's the other end and then + + + align:start position:0% +phosphate that's the other end and then +these are joined together this is one + + align:start position:0% +these are joined together this is one + + + align:start position:0% +these are joined together this is one +nucleotide here and the other here here + + align:start position:0% +nucleotide here and the other here here + + + align:start position:0% +nucleotide here and the other here here +these are then joined + + align:start position:0% +these are then joined + + + align:start position:0% +these are then joined +together to give the + + align:start position:0% +together to give the + + + align:start position:0% +together to give the +ordinary phosphodiester bond that + + align:start position:0% + + + + align:start position:0% + +links the two + + align:start position:0% + + + + align:start position:0% + +nucleotides together like that and the + + align:start position:0% +nucleotides together like that and the + + + align:start position:0% +nucleotides together like that and the +enzyme that does + + align:start position:0% + + + + align:start position:0% + +that it's an enzyme called DNA ligase + + align:start position:0% +that it's an enzyme called DNA ligase + + + align:start position:0% +that it's an enzyme called DNA ligase +you can almost think about it as as DNA + + align:start position:0% +you can almost think about it as as DNA + + + align:start position:0% +you can almost think about it as as DNA +Scotch tape it will take a little Nick + + align:start position:0% +Scotch tape it will take a little Nick + + + align:start position:0% +Scotch tape it will take a little Nick +in DNA we've got a phosphate and hydroxy + + align:start position:0% +in DNA we've got a phosphate and hydroxy + + + align:start position:0% +in DNA we've got a phosphate and hydroxy +and it'll it'll join them join them + + align:start position:0% +and it'll it'll join them join them + + + align:start position:0% +and it'll it'll join them join them +together so this process of of + + align:start position:0% +together so this process of of + + + align:start position:0% +together so this process of of +replication which can go at about a + + align:start position:0% +replication which can go at about a + + + align:start position:0% +replication which can go at about a +thousand + + align:start position:0% +thousand + + + align:start position:0% +thousand +nucleotides uh a second with this + + align:start position:0% +nucleotides uh a second with this + + + align:start position:0% +nucleotides uh a second with this +amazing degree of of accuracy uses two + + align:start position:0% +amazing degree of of accuracy uses two + + + align:start position:0% +amazing degree of of accuracy uses two +different DNA plases both of which can + + align:start position:0% +different DNA plases both of which can + + + align:start position:0% +different DNA plases both of which can +chem biochemically can only go in One + + align:start position:0% +chem biochemically can only go in One + + + align:start position:0% +chem biochemically can only go in One +Direction but you can see they have to + + align:start position:0% +Direction but you can see they have to + + + align:start position:0% +Direction but you can see they have to +be somehow oriented in um + + align:start position:0% +be somehow oriented in um + + + align:start position:0% +be somehow oriented in um +so that one of them is able to move in + + align:start position:0% +so that one of them is able to move in + + + align:start position:0% +so that one of them is able to move in +this direction and the other one is able + + align:start position:0% +this direction and the other one is able + + + align:start position:0% +this direction and the other one is able +to move in that direction the Strand + + align:start position:0% +to move in that direction the Strand + + + align:start position:0% +to move in that direction the Strand +um the the key part in this sort of the + + align:start position:0% +um the the key part in this sort of the + + + align:start position:0% +um the the key part in this sort of the +course is to try and understand this 5 + + align:start position:0% +course is to try and understand this 5 + + + align:start position:0% +course is to try and understand this 5 +to 3 Prime and to get this basic idea + + align:start position:0% +to 3 Prime and to get this basic idea + + + align:start position:0% +to 3 Prime and to get this basic idea +that nature had to do something it was + + align:start position:0% +that nature had to do something it was + + + align:start position:0% +that nature had to do something it was +fairly easy to copy one strand because + + align:start position:0% +fairly easy to copy one strand because + + + align:start position:0% +fairly easy to copy one strand because +that was sort of the direction of the + + align:start position:0% +that was sort of the direction of the + + + align:start position:0% +that was sort of the direction of the +Pumas movement was the same as the + + align:start position:0% +Pumas movement was the same as the + + + align:start position:0% +Pumas movement was the same as the +replication fork movement but the other + + align:start position:0% +replication fork movement but the other + + + align:start position:0% +replication fork movement but the other +strand had to been much more of a + + align:start position:0% +strand had to been much more of a + + + align:start position:0% +strand had to been much more of a +problem uh and so when you get down to a + + align:start position:0% +problem uh and so when you get down to a + + + align:start position:0% +problem uh and so when you get down to a +biochemical level though it's very + + align:start position:0% +biochemical level though it's very + + + align:start position:0% +biochemical level though it's very +conceptually easy to say oh you've got + + align:start position:0% +conceptually easy to say oh you've got + + + align:start position:0% +conceptually easy to say oh you've got +complimentary strand so we just take it + + align:start position:0% +complimentary strand so we just take it + + + align:start position:0% +complimentary strand so we just take it +apart we make a the take the photograph + + align:start position:0% +apart we make a the take the photograph + + + align:start position:0% +apart we make a the take the photograph +and negative and we make the opposite + + align:start position:0% +and negative and we make the opposite + + + align:start position:0% +and negative and we make the opposite +one and now we've got two copies when we + + align:start position:0% +one and now we've got two copies when we + + + align:start position:0% +one and now we've got two copies when we +get down to the biochemical details uh + + align:start position:0% +get down to the biochemical details uh + + + align:start position:0% +get down to the biochemical details uh +there is this major biochemical issue of + + align:start position:0% +there is this major biochemical issue of + + + align:start position:0% +there is this major biochemical issue of +whether the the plase uh can go in the + + align:start position:0% +whether the the plase uh can go in the + + + align:start position:0% +whether the the plase uh can go in the +three prime or the five Prime Direction + + align:start position:0% +three prime or the five Prime Direction + + + align:start position:0% +three prime or the five Prime Direction +and nature has chosen to do it all or + + align:start position:0% +and nature has chosen to do it all or + + + align:start position:0% +and nature has chosen to do it all or +has been selected to do it all some in + + align:start position:0% +has been selected to do it all some in + + + align:start position:0% +has been selected to do it all some in +with the plase going in one One + + align:start position:0% +with the plase going in one One + + + align:start position:0% +with the plase going in one One +Direction now there many uh many other + + align:start position:0% +Direction now there many uh many other + + + align:start position:0% +Direction now there many uh many other +aspects to this uh to DNA replication + + align:start position:0% +aspects to this uh to DNA replication + + + align:start position:0% +aspects to this uh to DNA replication +and one of the one of the tricks that I + + align:start position:0% +and one of the one of the tricks that I + + + align:start position:0% +and one of the one of the tricks that I +find Most Fascinating is that these + + align:start position:0% +find Most Fascinating is that these + + + align:start position:0% +find Most Fascinating is that these +polymerases once they get on DNA they + + align:start position:0% +polymerases once they get on DNA they + + + align:start position:0% +polymerases once they get on DNA they +stay on and that's part of the secret + + align:start position:0% +stay on and that's part of the secret + + + align:start position:0% +stay on and that's part of the secret +because it takes about a millisecond to + + align:start position:0% +because it takes about a millisecond to + + + align:start position:0% +because it takes about a millisecond to +add a nucleotide but if it comes off the + + align:start position:0% +add a nucleotide but if it comes off the + + + align:start position:0% +add a nucleotide but if it comes off the +DNA and has to get back on then uh it + + align:start position:0% +DNA and has to get back on then uh it + + + align:start position:0% +DNA and has to get back on then uh it +takes about a minute so the whole trick + + align:start position:0% +takes about a minute so the whole trick + + + align:start position:0% +takes about a minute so the whole trick +to being a very very fast DNA polymerase + + align:start position:0% +to being a very very fast DNA polymerase + + + align:start position:0% +to being a very very fast DNA polymerase +is to somehow hang on to the DNA so what + + align:start position:0% +is to somehow hang on to the DNA so what + + + align:start position:0% +is to somehow hang on to the DNA so what +biochemists did was they purified uh the + + align:start position:0% +biochemists did was they purified uh the + + + align:start position:0% +biochemists did was they purified uh the +actual enzymatic activity that could + + align:start position:0% +actual enzymatic activity that could + + + align:start position:0% +actual enzymatic activity that could +carry out this process and then they + + align:start position:0% +carry out this process and then they + + + align:start position:0% +carry out this process and then they +started to look for other protein + + align:start position:0% +started to look for other protein + + + align:start position:0% +started to look for other protein +factors that would help the process to + + align:start position:0% +factors that would help the process to + + + align:start position:0% +factors that would help the process to +work better and they discovered + + align:start position:0% +work better and they discovered + + + align:start position:0% +work better and they discovered +something called a processivity factor + + align:start position:0% +something called a processivity factor + + + align:start position:0% +something called a processivity factor +which made the plase stay on the on the + + align:start position:0% +which made the plase stay on the on the + + + align:start position:0% +which made the plase stay on the on the +DNA and people wondered for a lot of + + align:start position:0% +DNA and people wondered for a lot of + + + align:start position:0% +DNA and people wondered for a lot of +years how that works and why did this + + align:start position:0% +years how that works and why did this + + + align:start position:0% +years how that works and why did this +system work so well and finally the + + align:start position:0% +system work so well and finally the + + + align:start position:0% +system work so well and finally the +crystal structure of a of the + + align:start position:0% +crystal structure of a of the + + + align:start position:0% +crystal structure of a of the +processivity factor was discovered and + + align:start position:0% +processivity factor was discovered and + + + align:start position:0% +processivity factor was discovered and +if I go back to this this sort of + + align:start position:0% +if I go back to this this sort of + + + align:start position:0% +if I go back to this this sort of +diagram where this is the the piece of + + align:start position:0% +diagram where this is the the piece of + + + align:start position:0% +diagram where this is the the piece of +DNA that's copied what what it turned + + align:start position:0% +DNA that's copied what what it turned + + + align:start position:0% +DNA that's copied what what it turned +out was that the processivity factor is + + align:start position:0% +out was that the processivity factor is + + + align:start position:0% +out was that the processivity factor is +basically a donut that kind of gets + + align:start position:0% +basically a donut that kind of gets + + + align:start position:0% +basically a donut that kind of gets +clamped around the DNA like that so it's + + align:start position:0% +clamped around the DNA like that so it's + + + align:start position:0% +clamped around the DNA like that so it's +it's like sort of taking a a washer with + + align:start position:0% +it's like sort of taking a a washer with + + + align:start position:0% +it's like sort of taking a a washer with +a place where you can pry it apart + + align:start position:0% +a place where you can pry it apart + + + align:start position:0% +a place where you can pry it apart +opening it up putting it around the DNA + + align:start position:0% +opening it up putting it around the DNA + + + align:start position:0% +opening it up putting it around the DNA +like this and then the pimas more or + + align:start position:0% +like this and then the pimas more or + + + align:start position:0% +like this and then the pimas more or +less since it's now to this is + + align:start position:0% +less since it's now to this is + + + align:start position:0% +less since it's now to this is +topologically linked to the DNA it's + + align:start position:0% +topologically linked to the DNA it's + + + align:start position:0% +topologically linked to the DNA it's +like a a washer sliding on a wire this + + align:start position:0% +like a a washer sliding on a wire this + + + align:start position:0% +like a a washer sliding on a wire this +DNA polymerase hangs onto that and it + + align:start position:0% +DNA polymerase hangs onto that and it + + + align:start position:0% +DNA polymerase hangs onto that and it +doesn't come off and the I think there's + + align:start position:0% +doesn't come off and the I think there's + + + align:start position:0% +doesn't come off and the I think there's +a little picture of the here's a little + + align:start position:0% +a little picture of the here's a little + + + align:start position:0% +a little picture of the here's a little +movie there's the DNA going through and + + align:start position:0% +movie there's the DNA going through and + + + align:start position:0% +movie there's the DNA going through and +this is one of these uh one of these + + align:start position:0% +this is one of these uh one of these + + + align:start position:0% +this is one of these uh one of these +clamps it's the virtually the same + + align:start position:0% +clamps it's the virtually the same + + + align:start position:0% +clamps it's the virtually the same +structure in a bacterium and inside of + + align:start position:0% +structure in a bacterium and inside of + + + align:start position:0% +structure in a bacterium and inside of +us but in fact the amino acids are + + align:start position:0% +us but in fact the amino acids are + + + align:start position:0% +us but in fact the amino acids are +almost all all different but the the + + align:start position:0% +almost all all different but the the + + + align:start position:0% +almost all all different but the the +underlying structure of the protein is + + align:start position:0% +underlying structure of the protein is + + + align:start position:0% +underlying structure of the protein is +almost identical and there's there are a + + align:start position:0% +almost identical and there's there are a + + + align:start position:0% +almost identical and there's there are a +little special machines that will kind + + align:start position:0% +little special machines that will kind + + + align:start position:0% +little special machines that will kind +of called clamp loaders that pry open + + align:start position:0% +of called clamp loaders that pry open + + + align:start position:0% +of called clamp loaders that pry open +these clamps clamp them around DNA and + + align:start position:0% +these clamps clamp them around DNA and + + + align:start position:0% +these clamps clamp them around DNA and +that's part of the secret to how these + + align:start position:0% +that's part of the secret to how these + + + align:start position:0% +that's part of the secret to how these +uh plases are able to + + align:start position:0% +uh plases are able to + + + align:start position:0% +uh plases are able to +be uh polymerized DNA so fast + + align:start position:0% +be uh polymerized DNA so fast + + + align:start position:0% +be uh polymerized DNA so fast +there are a lot of other pieces of this + + align:start position:0% +there are a lot of other pieces of this + + + align:start position:0% +there are a lot of other pieces of this +Machinery if you go on you'll hear more + + align:start position:0% +Machinery if you go on you'll hear more + + + align:start position:0% +Machinery if you go on you'll hear more +of it I just want to give you one of the + + align:start position:0% +of it I just want to give you one of the + + + align:start position:0% +of it I just want to give you one of the +most recent insights I mean this has + + align:start position:0% +most recent insights I mean this has + + + align:start position:0% +most recent insights I mean this has +been studied in this as you might guess + + align:start position:0% +been studied in this as you might guess + + + align:start position:0% +been studied in this as you might guess +since DNA replication is at the heart of + + align:start position:0% +since DNA replication is at the heart of + + + align:start position:0% +since DNA replication is at the heart of +life it's been studied very very hard + + align:start position:0% +life it's been studied very very hard + + + align:start position:0% +life it's been studied very very hard +ever since the uh discovery of DNA Helix + + align:start position:0% +ever since the uh discovery of DNA Helix + + + align:start position:0% +ever since the uh discovery of DNA Helix +my colleague Alan Gman um made quite a + + align:start position:0% +my colleague Alan Gman um made quite a + + + align:start position:0% +my colleague Alan Gman um made quite a +discovery uh just probably 3 or four + + align:start position:0% +discovery uh just probably 3 or four + + + align:start position:0% +discovery uh just probably 3 or four +years ago uh he was he took that green + + align:start position:0% +years ago uh he was he took that green + + + align:start position:0% +years ago uh he was he took that green +fluorescent protein that we've seen a + + align:start position:0% +fluorescent protein that we've seen a + + + align:start position:0% +fluorescent protein that we've seen a +few times and he actually joined the uh + + align:start position:0% +few times and he actually joined the uh + + + align:start position:0% +few times and he actually joined the uh +the gene en coding green floresent + + align:start position:0% +the gene en coding green floresent + + + align:start position:0% +the gene en coding green floresent +protein to the back end of a piece of + + align:start position:0% +protein to the back end of a piece of + + + align:start position:0% +protein to the back end of a piece of +the DNA plase so wherever the DNA plase + + align:start position:0% +the DNA plase so wherever the DNA plase + + + align:start position:0% +the DNA plase so wherever the DNA plase +went now there was a little + + align:start position:0% +went now there was a little + + + align:start position:0% +went now there was a little +fluorescent molecule and he looked to + + align:start position:0% +fluorescent molecule and he looked to + + + align:start position:0% +fluorescent molecule and he looked to +see where it was in the cell and I like + + align:start position:0% +see where it was in the cell and I like + + + align:start position:0% +see where it was in the cell and I like +many other people had for years taught + + align:start position:0% +many other people had for years taught + + + align:start position:0% +many other people had for years taught +this is why you know I have respect for + + align:start position:0% +this is why you know I have respect for + + + align:start position:0% +this is why you know I have respect for +the fact that I'm just teaching you the + + align:start position:0% +the fact that I'm just teaching you the + + + align:start position:0% +the fact that I'm just teaching you the +current model uh for much of my career I + + align:start position:0% +current model uh for much of my career I + + + align:start position:0% +current model uh for much of my career I +taught so DNA plas is sort of like a + + align:start position:0% +taught so DNA plas is sort of like a + + + align:start position:0% +taught so DNA plas is sort of like a +train going down the tracks th mile + + align:start position:0% +train going down the tracks th mile + + + align:start position:0% +train going down the tracks th mile +molecules per second and we're doing all + + align:start position:0% +molecules per second and we're doing all + + + align:start position:0% +molecules per second and we're doing all +this stuff with the leading and the the + + align:start position:0% +this stuff with the leading and the the + + + align:start position:0% +this stuff with the leading and the the +with the two strands um actually let me + + align:start position:0% +with the two strands um actually let me + + + align:start position:0% +with the two strands um actually let me +just put those words up while I'm up + + align:start position:0% +just put those words up while I'm up + + + align:start position:0% +just put those words up while I'm up +there this + + align:start position:0% +there this + + + align:start position:0% +there this +one this is + + align:start position:0% +one this is + + + align:start position:0% +one this is +called The Strand that's + + align:start position:0% +called The Strand that's + + + align:start position:0% +called The Strand that's +easy easy to replicate is called the + + align:start position:0% +easy easy to replicate is called the + + + align:start position:0% +easy easy to replicate is called the +leading + + align:start position:0% + + + + align:start position:0% + +Strand and this one you have have to do + + align:start position:0% +Strand and this one you have have to do + + + align:start position:0% +Strand and this one you have have to do +the primer what not is called the + + align:start position:0% +the primer what not is called the + + + align:start position:0% +the primer what not is called the +lagging + + align:start position:0% + + + + align:start position:0% + +strand in any case um so what I had + + align:start position:0% +strand in any case um so what I had + + + align:start position:0% +strand in any case um so what I had +taught was the ply was was like a A + + align:start position:0% +taught was the ply was was like a A + + + align:start position:0% +taught was the ply was was like a A +train running on tracks you could even + + align:start position:0% +train running on tracks you could even + + + align:start position:0% +train running on tracks you could even +calculate how fast it would move what + + align:start position:0% +calculate how fast it would move what + + + align:start position:0% +calculate how fast it would move what +alen to his amazement I imagine found + + align:start position:0% +alen to his amazement I imagine found + + + align:start position:0% +alen to his amazement I imagine found +was when he looked to see where the DNA + + align:start position:0% +was when he looked to see where the DNA + + + align:start position:0% +was when he looked to see where the DNA +plase was it wasn't spread out all over + + align:start position:0% +plase was it wasn't spread out all over + + + align:start position:0% +plase was it wasn't spread out all over +the cell as if you thought it was a a + + align:start position:0% +the cell as if you thought it was a a + + + align:start position:0% +the cell as if you thought it was a a +thing running in tracks in fact it was + + align:start position:0% +thing running in tracks in fact it was + + + align:start position:0% +thing running in tracks in fact it was +in the center of the cell and then Laden + + align:start position:0% +in the center of the cell and then Laden + + + align:start position:0% +in the center of the cell and then Laden +cell division it split into two spots + + align:start position:0% +cell division it split into two spots + + + align:start position:0% +cell division it split into two spots +that went to the midpoints of what would + + align:start position:0% +that went to the midpoints of what would + + + align:start position:0% +that went to the midpoints of what would +be the daughter cells and so what he + + align:start position:0% +be the daughter cells and so what he + + + align:start position:0% +be the daughter cells and so what he +ended up realizing from that was that + + align:start position:0% +ended up realizing from that was that + + + align:start position:0% +ended up realizing from that was that +instead it was more as if the Plumas was + + align:start position:0% +instead it was more as if the Plumas was + + + align:start position:0% +instead it was more as if the Plumas was +a a factory and it pulled the DNA + + align:start position:0% +a a factory and it pulled the DNA + + + align:start position:0% +a a factory and it pulled the DNA +through it rather than it traveling down + + align:start position:0% +through it rather than it traveling down + + + align:start position:0% +through it rather than it traveling down +the down the tracks of the of the DNA + + align:start position:0% +the down the tracks of the of the DNA + + + align:start position:0% +the down the tracks of the of the DNA +and that has that was a very surprising + + align:start position:0% +and that has that was a very surprising + + + align:start position:0% +and that has that was a very surprising +discovery that went against all the + + align:start position:0% +discovery that went against all the + + + align:start position:0% +discovery that went against all the +Dogma and all the pictures in the + + align:start position:0% +Dogma and all the pictures in the + + + align:start position:0% +Dogma and all the pictures in the +textbook and it was a discovery made in + + align:start position:0% +textbook and it was a discovery made in + + + align:start position:0% +textbook and it was a discovery made in +MIT that was published in I think it was + + align:start position:0% +MIT that was published in I think it was + + + align:start position:0% +MIT that was published in I think it was +2001 something like that a very recent + + align:start position:0% +2001 something like that a very recent + + + align:start position:0% +2001 something like that a very recent +discovery things keep changing it's + + align:start position:0% +discovery things keep changing it's + + + align:start position:0% +discovery things keep changing it's +again why I keep emphasizing I can I + + align:start position:0% +again why I keep emphasizing I can I + + + align:start position:0% +again why I keep emphasizing I can I +can't teach you a fact in biology I can + + align:start position:0% +can't teach you a fact in biology I can + + + align:start position:0% +can't teach you a fact in biology I can +teach you the best understanding we have + + align:start position:0% +teach you the best understanding we have + + + align:start position:0% +teach you the best understanding we have +that's that's that explains the + + align:start position:0% +that's that's that explains the + + + align:start position:0% +that's that's that explains the +experiments to date but somebody may + + align:start position:0% +experiments to date but somebody may + + + align:start position:0% +experiments to date but somebody may +make a discovery tomorrow that means + + align:start position:0% +make a discovery tomorrow that means + + + align:start position:0% +make a discovery tomorrow that means +we'll have to change your understanding + + align:start position:0% +we'll have to change your understanding + + + align:start position:0% +we'll have to change your understanding +okay so good luck on the exam I'll see + + align:start position:0% +okay so good luck on the exam I'll see + + + align:start position:0% +okay so good luck on the exam I'll see +you on on Monday + + align:start position:0% + + + + align:start position:0% + +okay \ No newline at end of file diff --git a/2QRfkG7jOfY.txt b/2QRfkG7jOfY.txt new file mode 100644 index 0000000000000000000000000000000000000000..2b7e7e5d52c7511cbf24d783092ad869328d6836 --- /dev/null +++ b/2QRfkG7jOfY.txt @@ -0,0 +1,3813 @@ +We're about ready to get started. + +A couple things. + +First of all, this is for those of you who +are working on GN&C for your projects. + +I have spoken with Phil Hattis from Draper +Lab, who is going to be giving the lecture + +on GN&C, but he is not giving the lecture +until the third of November. + +Now, that is kind of late. + +And so I asked him if he would be willing +to meet with all of you who are working on + +GN&C just so you could talk with him and ask +questions. + +If you want him to give you a short version +of his presentation that he's going to give + +in November, he can do that. + +But he is our in-house resident expert. + +And I figured it's better if you get a chance +to talk to him early. + +He has some time free tomorrow and he has +some time next week. + +He is out of town through today. + +I know we have two teams working on GN&C. + +If you guys want to get together and find +out if there is some time when you could all + +meet with Phil, I will give you his contact +information. + +He says he is happy to do it. + +It would be much more convenient, from his +point of view, if you could all see him at + +the same time and talk about it together. + +Let me know what you come up with. + +But, as I say, he is happy to do it. + +Second thing. + +There was an interview printed in US Today, +which I have posted on the class website with + +Mike Griffin, the administrator. + +And it says NASA administrator says space +shuttle was a mistake. + +And so the question was what do we intend +to do about that in this class? + +Well, let me actually read the specific words +that Griffin uses because I think that's important. + +Griffin said my opinion is that the Shuttle +was a design which was extremely aggressive + +and just barely possible. + +And that's actually, I think, a slightly different +way of looking at this. + +I mean I would also say that Apollo was a +project that was extremely aggressive and + +just barely possible. + +And I think that it is actually NASA's business +to do things which are aggressive and just + +barely possible. + +Now, whether it was the right decision for +the country to abandon the Exploration Program + +after Apollo and do the Shuttle and then later +on the Space Station that's more, I think, + +in the political realm. + +And, as I think you've heard both from Dale +Myers and John Logsdon, that, in fact, there + +were political determining factors which didn't +really give NASA a lot of choice. + +Just to remind you, the basic point of this +course is not the political and economic history + +of the shuttle. + +It's a technical exploration of how we did +the shuttle. + +I think we would all agree that the concept +of the Shuttle was extremely aggressive and + +the technology was being stretched and it +was just barely possible. + +And, yet, we did it. + +And the idea of this course is to understand +how we did it and how the systems work. + +I think it will be interesting, when we get +towards the end of the course, maybe we'll + +sit down and relax and instead of having, +I think there are two kinds of open sessions + +towards the end that I've been thinking about +what we want to do there. + +And in one of them I think we may just talk +a little bit and reflect on what we've learned, + +and that will give us an opportunity to discuss +issues like this. + +That's all I'm going to say about this. + +I don't propose that we discuss this further +today because we really are fortunate to have + +Bass Redd. + +And Aaron Cohen is going to introduce him +formally. + +I will just say that when I was at Johnston +Space Center last spring and I met one of + +the older managers there and I was telling +him about our plans for this course and how + +Aaron was going to be a visiting professor +here and we were inviting some of the experts + +in the early design of the Shuttle, he said, +well, there is one guy you absolutely have + +to get, and that's Bass Redd. + +Well, we've got him. + +We're very fortunate. + +And, Aaron, I will turn it over to you and +let you explain a little bit more why we're + +so fortunate. + +Well, first I have to tell you how I found +Bass. + +I had a hard time finding Bass. + +He lives in a placed called Smithville, Texas. + +And, when people ask him where Smithville, +Texas is, he said it's about a few minutes + +after you pass resume speed. + +So, it's not a very well known place. + +But I finally found Bass. + +And he is truly an outstanding aerodynamicist. + +And the thing that is so important is that +aerodynamics, to me, from my vantage point, + +is really the linchpin, you might say, of +putting a system together. + +Aerodynamics makes the system come alive. + +And as you could hear from the various speakers, +from Tom Moser, and we talked a little bit + +about the guidance, navigation and control, +it's important for the structures. + +Aerodynamics is important for the structures, +it's important for the flight control system, + +it's important for the hydraulic system and +it's important for the heating system. + +So, you have to understand the aerodynamics +before you can make the vehicle actually come + +alive. + +And Bass Redd is the man to do it. + +He is absolutely one of the great aerodynamicists +of our times. + +And he started out before there was computational +fluid dynamics and the old wind tunnel testing. + +And now there is computational fluid dynamics, +so you're going to be in for a real treat + +today to hear how Bass Redd put both the Apollo +together, he did the Apollo aerodynamics, + +and he also did the Shuttle aerodynamics. + +And he is also now consulting to help NASA +do their future work. + +Let me now turn it over to Bass. + +Thank you, Aaron. + +It's a great honor to be with you this morning. + +And you sure do look young. + +[LAUGHTER] We will try to cover basically +-- [STATIC OBSCURES] And with that overview + +then of the Orbiter is how the program requirements +drove the aerodynamic configuration, probably + +the biggest thing in what the aerodynamic +characteristics are driven by the program + +requirements. + +And that will make a little more sense after +we get into the briefing. + +Then the aerodynamic considerations, those +that aren't due to program requirements but + +just due to the basic fundamentals of aerodynamics +and the configuration that is being evaluated. + +We will do that for both the Orbiter and the +Integrated Vehicle. + +Then I'll try to tell you how the aerodynamic +design was accomplished through each of those + +phases, a lot of ways to work problems. + +Early on having powerful tools or sometimes +a curse to you because you can produce more + +data than the system can consume. + +And I remember when we first got started on +the Shuttle design, the people from structures + +had just finished the NASTRAN on the Apollo +and they immediately wanted enough data to + +put into the NASTRAN for every configuration +that was being conceived. + +That's not really a smart thing to do when +you have literally hundreds of configurations + +to be considered. + +We will try to talk to you about phases, phase +A, B and C, and defining the problem areas. + +And then defining the aerodynamic characteristics +and do just a quick summary of the wind tunnel + +test program. + +And with some comments on how CFD might have +driven that were it available. + +Through the `60s and `80s these design studies +were accomplished in phases. + +Phase A is primarily in-house civil service +design. + +I don't know how well you understand the NASA +part, what the contractor part, what the civil + +service part is, but phase A is primarily +in-house civil service. + +Whenever the contractors began to feel that +this might be a real program, they began to + +do their in-house studies and they began to +visit and give us recommendations and ideas + +on their own to drive that. + +None of that is paid for. + +That's a gratuitous kind of a thing. + +And contractors have a bit of change set aside +to do those kinds of studies, but it's a freebee + +and really a super way to do things. + +And that's still going on today. + +Phase B is then you give contracts for generic +studies. + +Scopes out the concept feasibilities and the +program requirements and does those trades, + +does projected cost and timelines. + +By the way, before I forget it, Humboldt Mandell +on costing would be excellent. + +We worked quite close hand-in-hand on trying +to get those requirements and cost run together + +along with the weight. + +NASA then, after they get through this phase +B, they produce a detailed statement of work + +that +is required for the phase C and D. + +And then phase C and D is the design and development. + +The Air Force separated those two. + +NASA always sort of put those together. + +So the design, development and construction. + +And the contractors do the detail work. + +NASA manages and checks it. + +Usually the way we operate, at least in our +area, the aerodynamic area, we had a crack + +team that would go back in and define the +problem, a potential solution to that problem + +and then suggest to the contractor they might +look at this way or that way. + +But they really put the muscle to it. + +They put the final studies. + +They have the design documentation. + +And we try to steer that train as those things +happen. + +In the Shuttle now, phase A, we started in +1969, just shortly after the Lunar landing, + +they put together a small team. + +And this is at Johnson Space Craft Center. + +And that's through my knothole and the way +that I look at things. + +But we did end up being the lead center in +the shuttle. + +But we started with a small E&D group that +was headed by a fellow by the name of Jim + +Chamberlain. + +Jim Chamberlain was the one that was responsible +for the Gemini Space Craft, a very unique + +individual gone to heaven to be with the Lord +now, reviewed by Max Faget who was head of + +E&D and Bob Gilruth who was center director, +but that was a real privilege to work with + +him. + +What came out of that initial phase A study +is what the vehicle should be, is a small + +personnel vehicle with a four man crew, 10k +payload landing on the runway with about 200 + +nautical miles cross-range. + +Quite different from the shuttle that we have +today, but that was during the phase A. + +Strong design modules in this time were developed. + +And, showing how the other program requirements +go with the design, the size and the program + +cost, there were individuals who had in their +databank, which consisted of books that they + +kept on their tables, were all of the aircraft, +all of the spacecraft, all of the missiles, + +what the weight of every individual subsystem +was based upon plots with ECLS's on how much + +heat they took out, on the avionics as to +how many computations they made. + +Well, not to chase that rabbit too far, but +basically they were down to the subsystem + +kind of level. + +And then with the primary structure, secondary +structure, how that was affected by landed + +weights or entry weights, the thermal protection +system. + +And it was amazing what a good job that kind +of approach would do. + +And then we had point designs that were being +looked at both in-house at Johnson Space Craft + +Center, at Marshall and by all the contractors. + +And then all that data was fed into the system. + +So, that was a designed database. + +Some of those have been automated now and +pretty good. + +And they don't give you the right answers, +but the answers they give you aren't very + +far wrong either. + +They get into the ballpark for you. + +Phase B started in 1971. + +Something happened. + +The requirements were not dictated by NASA. + +The requirements were dictated by the Air +Force, at least the driving requirements. + +If we had our own, a small vehicle it would +have satisfied that. + +The Air Force requirements were 55,000 pound +payload, 60 foot long payload bay, 15 foot + +in diameter, it had to be returned with a +1200 nautical mile cross-range. + +At least 32,000 pounds of it had to be returned. + +It was classified at that time. + +It is no longer classified. + +You can use your imagination to figure out +what kind of payload that you would want to + +go up into a high inclination orbit and bring +back in one pass. + +Where that would take you and why you'd have +to get back that quickly. + +But those were the requirements that were +fed into phase B. + +Maximum reusability did not come from the +Air Force. + +That came from the NASA side as that was part +of technology. + +NASA has two basic jobs to do. + +One is the design of the vehicle, the delivering +of the hardware, accomplishing the mission, + +but the other requirement for NASA is that +it increased the technology. + +Going where no man has gone before, yes, but +doing things that man has not done before + +in a better, faster way. + +And so maximum reusability was a goal that +the engineers were handed. + +Soft ride. + +They wanted to be able to a congressman or +a senator up in it. + +[LAUGHTER] A neat thing. + +Multi-center participation. + +If you ever get Hum up here, that cost you. + +Any time you break a job down and give it +to more than one center or more than one contractor, + +it's like Humpty-Dumpty, you break him apart, +you've got to put him back together again. + +And it takes a lot of eyes and elbows on both +sides to accomplish that. + +And basically, once you break something down, +you've increased your cost by 30% to 40% to + +put it back together again. + +Now, NASA has to have, under congressional +mandate, contracts in every state in the union. + +Multi-center participation drives a great +number of things so I felt it needed to be + +on the chart. + +But the big thing that you need to know as +engineers, sometimes you cannot set your own + +program requirements. + +They are dictated to you for strange reasons. + +And you have to play the hand that you're +dealt. + +Phase C and D, we had four contractors that +bid on phase C and D. + +The interesting thing is Rockwell was the +only contractor that bid within the allocated + +funds. + +They also had the best proposal, but that +was very interesting. + +What they did was use the aerodynamic database +that was developed in phase A and in phase + +B for their design analysis. + +They augmented that, they did some in-house +testing, and Rockwell said we can do it for + +that amount of money but only if you don't +change anything, NASA. + +And we changed things. + +They had a smaller orbiter, and we rejected +that very early on. + +It had no capability for weight growth. + +And we showed that every program that has +ever existed grew in weight by at least 5%, + +10%, 15%. + +And so the Orbiter was sized up just a little +bit larger than the one that they had proposed + +with their agreement. + +Aaron probably had a contract change authorization +because of that. + +But, anyway, we did that right at the beginning. + +What we did also aerodynamically during that +phase B is we developed a complete database + +in the nation's best facility to be used for +what we call verification analysis. + +And that database is very well documented, +and we will talk about that a little bit more. + +Program requirements. + +May I ask, before you go onto program requirements, +could you say something about kind of, you + +talked about the aerodynamic database, but +nowadays we've got a lot of information about + +hypersonic aerodynamics? + +Can you say a little bit about the state of +the art? + +What did people really know? + +Yeah. + +As a matter of fact, I'm going to do that +when we go through it by phases specifically. + +I'm kind of telling it to you like a mystery +story. + +[LAUGHTER] The program requirements dictated +the basic orbiter configuration, payload size, + +crew size and returning the payload bay, the +engine. + +Now, if you just visualize in your mind, and +it's kind of a two-chart thing, let me just + +jump over to that since I know how to go back +now. + +If you've got a payload that's got to be that +long and you've got a crew size and the crew + +takes at least one telephone booth's worth +of volume per crew takes at least one telephone + +booths worth of volume per crew, Even Superman +needed something that big. + +[LAUGHTER] You've got the volume of this. + +Engines in the back. + +You want to return that because engines are +very, very expensive. + +The avionics, of course, you want to bring +those back. + +They are very, very expensive. + +And you've got to have it pointy end first. + +You looked at that and said, boy, you didn't +have much choice as far as the fuselage was + +concerned. + +And that's right, you really don't. + +Now, that's pretty well set. + +Now, the wing size is required to augment +the body lift. + +Now, if you just had the body on there, it +would have to land about 300 knots. + +We didn't have wheel tires and breaks to land +at that those speeds so we had to have some + +more lift. + +And that was accommodated with a wing. + +Figure out what CL max is. + +They're all about the same. + +You like a delta wing because it's a little +more nice from a heat transfer standpoint. + +Sure a whole lot nicer if you've got to go +through supersonic and transonic conditions + +at low angles of attack. + +So, you've got a delta wing that you want +to have on there. + +You don't have much choice on the size of +that. + +Airflow by the way 12% thick. + +That makes it nice for the structures people. + +Still does a super job aerodynamically, too. + +And so that's pretty well dictated. + +Then the entry angle of attack is dictated +by the hypersonic L/D required for the cross-range. + +And you can go through your equations, Newtonian +aerodynamics sign or the exposed area, and + +the then L/D, the tangents. + +And so you've got the hypersonic aerodynamics +from that angle of attack required for the + +cross-range. + +The wing shape to balance the configuration +for the aft CG and acceptable wing leading + +edge heating. + +In other words, we can position that wing +at the right place for the center of gravity + +that we have which, by the way, even in phase +A is known pretty well didn't change much. + +The control services was the magic thing. + +With the payload in and out 1.5% CG changed. + +There has only been one other aerodynamic +vehicle that has ever been built that has + +a CG of 1.5% of body length. + +That was a B-36. + +And this vehicle had to have the 1.5% change +in the center of gravity because of payload + +in/ payload out. + +And you can try to stack it together in many +different ways. + +That's just as good as you can do. + +That dictated the size of the control services +to accommodate that. + +They are very big. + +They are barn doors. + +It makes it nice for controlling the vehicle. + +Oh, and the vertical tail, we'll talk about +that. + +That's for crosswind landings. + +But the way, most all the vehicles that you've +seen from overseas that have been proposed + +cannot land in a crosswind. + +I don't know what they are going to do. + +They don't have enough control service to +land in the crosswind. + +But that dictated the vertical tail size. + +Now, as you kind of go around the loop on +those things, some potential items that we + +probably want to point out here is the body +shape. + +We've already basically talked about it. + +Nose shape, that's pretty straight forward. + +The basic Orbiter shape didn't really change +from phase A through phase C and D. + +We blended the OMS pot a little bit because +we didn't want it to interfere with the payload + +bay door which was built by a different set +of groups. + +The delta wing, we put a little crank in it, +a double delta, and got a little more subsonic + +lift. + +And we didn't have the body flap moving to +start with, but we found that it was a very + +powerful control of which assisted the center +of gravity movement. + +The full-spanned elevons were needed to control +the center of pressure for hypersonics. + +And there are other little things there, and +you can read those through at your convenience, + +but those are just basic things that you have +to do. + +And we will comment on some of those a little +bit later. + +The Integrated Vehicle, the launch vehicle, +if you please, what do the program requirements + +do to it? + +Well, the Orbiter was sized for that payload +bay weight. + +It had to land. + +It had to enter. + +We knew the weights pretty well. + +The 150k pound Orbiter, the 65k pound payload +dictated the requirements of the Orbiter injected + +weight. + +You add them up. + +You've got to get it into orbit. + +Once around at the high inclination and return +to the launch site set the Orbiter performance + +requirements. + +We had to have a certain amount of energy +available from the propulsion system. + +Maximum hardware reusability mixed with a +cost consideration yielded a stage and a half + +vehicle. + +And I will talk to you about that in just +a minute. + +But the cost constraints, there was a great +move afoot to have a return to the launch + +site booster, manned booster, if you please, +but the cost and constraints and the size + +of the vehicle got pretty big. + +The wing vehicle loads were significantly +reduced by the parallel burn. + +You've got the orbiter tucked in between the +solid rocket boosters and the external tank + +versus an orbiter that would be on the end. + +It makes a great difference in the structural +loads that the aerodynamics produces. + +Solid rocket booster mismatch decreased or +dictated an increased beta dispersion. + +Typically on an end-to-end vehicle you've +got everything kind of tucked in pretty tightly. + +On this one the SRBs are spread, any mismatch +at burnout and we had some big beta dispersions + +that still haunt us a little bit today. + +Soft ride requirement. + +Yes, I'm sorry. + +I just don't know what a beta dispersion is. + +You don't know what a beta dispersion is. + +All right. + +[LAUGHTER] Angle of attack. + +Angle the size of it, beta. + +Alpha, beta, standard aerodynamic definition. + +Which, by the way, brings me to a comment. + +We've been asked to chase a rabbit with you +here. + +I would suggest very highly that you get yourself +a NASA dictionary where standard terms that + +your bosses will use because they've been +using them for years. + +[LAUGHTER] That you do that. + +And I'm not fussing at you at all. + +You can get a little gray book that's called +the NASA Dictionary. + +And you will know what alpha and betas are. + +CMQ plus CM alpha dots. + +All those standards terms are defined. + +Flutter. + +Buffet. + +And you will really look sharp when you know +what he's saying. + +[LAUGHTER] All right. + +Go ahead. + +I know there are some people here who didn't +go through aero-astro, and so may have actually + +not had a full course in aerodynamics. + +Hopefully most of you have had it. + +But any time there are expressions or terms +you don't understand just do ask and we'll + +bring you up to speed. + +And that NASA dictionary, by the way, covers +not just aerodynamics. + +It covers all kinds of other vocabulary kinds +of things that your peers will be using and + +your supervisors will be using and you will +know what they're talking about. + +Soft ride requirements, that caused us to +go to a real low dynamic pressure which is + +nice. + +Most vehicles are up around 1200 pounds per +square foot dynamic pressure. + +This one is down around 800. + +And the reason that came about is lesser G +loads early on. + +SRB flare angle, no big deal there. + +Plume effects have really ate up aerodynamics. + +To this day that is the only thing aerodynamically +that we still don't know how to predict or + +the base pressure due to plume effects through +the subsonic and supersonic speed regime. + +CFD gets it right every now and then. + +Sometimes it doesn't get it right. + +And the wind tunnel test still hadn't got +it right with solid plumes. + +All the scaling parameters that you use still +don't produce, to me, what a real valid answer + +is. + +The flight data is used, and we update that. + +Yes, sir. + +When you say flare angle, do you mean like +in the stack away from the Orbiter? + +Yes, sir. + +This flare angle right back here. + +We found that if you set that right, it pretty +well sets the flow and the plumes behave themselves. + +If you set that too small the plumes will +change greatly with mach numbers, sometimes + +in an unpredictable fashion, so that SRB skirt +size was primarily from that consideration. + +This is real precious to Aaron's heart. + +We changed the tank shape early in phase C +and D. + +And remember I told you that we had developed +a database during phase B that would suffice + +and we could go immediately into the design +and development of the total stack? + +By the way, I like the ogive. + +It's a lot prettier than the cone that we +had on the front end. + +But basically what that did, that changed +the aerodynamics of the whole stack. + +And the data that was delivered to structure +for their structural analysis, the data that + +was delivered to the heating people for their +heat transfer analysis had to be done all + +over again. + +That's a year and a half cycle from the time +you say let's go build a model, let's get + +the data, let's analyze it. + +The other thing that happened when we changed +the tank, everybody took note of that, and + +there are all kinds of other small changes +that jumped on. + +[LAUGHTER] On the Orbiter a little bit, on +the external tank, on the SRBs and on the + +inclination that we had between the Orbiter +and the tank. + +Let me just hit some things I think that you +want to take note of on this one. + +I guess the nose shape, we mentioned that +one already, reduces the drag. + +It also reduces the loads. + +We have to worry about the punch loads between +the SRB and the tank. + +And those aerodynamics are driven quite a +bit by that nose shape. + +The SRB locations fore and aft, there is some +adjustment that you can have in that, and + +those are all optimized that whenever we do +the aerodynamics that puts a minimum amount + +of load into the system. + +Orbiter instance angle, that's the angle between +the Orbiter and the external tank. + +It drives the stability of the configuration +to some degree. + +But, more than that, it drove the loads quite +a bit into the program. + +And that was optimized. + +Full span elevators, we use those to adjust +the pitching moments so we get minimum change + +required to trim the vehicle from the SRBs, +solid rocket boosters, and the SSMEs, the + +main shuttle engines. + +SSME, plume effects and the plume effects +from the SRB, that's the only thing that we + +got a bad grade on as far as predicting aerodynamics +on either the Orbiter or the Integrated Vehicle. + +All the rest of the stuff came out just about +as we had predicted. + +Now, getting back to where you asked the question. + +Phase A. + +Go back now. + +What is a phase A? + +That is the conceptual design. + +We had all kinds of configurations because +we had all kinds of requirements. + +We really didn't know what those were, and +so that analysis had to be done. + +Many, many vehicles. + +A lot of considerations. + +The analytical techniques we used to identify +problem areas. + +Hypersonics, quite frankly in phase A. + +Newtonian vehicle shape was approximated with +flat plates. + +Works great on a configuration. + +[LAUGHTER] That's pretty much like a vehicle +that is kind of trimmed out of a piece of + +a sphere, if you please. + +And those aerodynamic characteristics were +very good. + +As a matter of fact, the thing is laid out +on graph paper and you counted the squares + +and saw where the CG was and what things had +to be. + +And it worked. + +It worked. + +Now, we didn't know that it was working at +that time. + +But we found out later that it did. + +But that's what we used. + +[LAUGHTER] NASA documentation. + +NASA had pretty good TNs on vehicles that +were somewhat similar. + +And the characteristics of those, we made +the adjustments because of the difference + +in configuration. + +The Air Force had a document called Dataman. + +It was unpublished at that time, but we got +a preliminary draft that we worked through + +by hand. + +By the way, this is a published thing. + +I would suggest very highly if aerodynamics +is going to be your forte is that you learn + +how to use that program. + +It's Dataman Aerodynamics Handbook. + +Navel Ordinance had a handbook out. + +They've never computerized theirs, but it's +the Handbook of Supersonic Aerodynamics and + +good-old Horner's fluid dynamics lift and +drag. + +It is still around today, still use it, but +those were the aerodynamic methods that we + +used during phase day. + +And we also did small scale wind tunnel tests +and those things that were the problem areas. + +And the problem areas were primarily in the +transition. + +Yes, sir. + +I can understand how you can do wind tunnel +testing. + +What about plume effects? + +You said you didn't understand those. + +How do you test that experimentally? + +[UNINTELLIGIBLE PHRASE] No, that's done in +a wind tunnel. + +Some people said you need to match momentum +on a scale vehicle. + +Certain other characteristics. + +What you'd like to do is be able to simulate +it with a solid plume, so we did solid plume + +testing. + +We had method of characteristics back then. + +It took it about three weeks to run, to get +the plume sizes, and they did a pretty good + +job. + +But when you have the plume sizes you still +after the base effects change in the pitching + +moment. + +And so we did the solid plumes. + +And we did gaseous plumes at Ames Research +Center. + +We did cold gas and hot gas. + +But none of those met all the scaling parameters. + +When you rolled all that up and you did the +best you could, we still missed base pressure. + +Base pressure was missed on Saturn 5. + +Base pressure was missed on Mercury. + +Base pressure was missed on Little Joe II +and Little Joe I. + +Every launch vehicle that I could find we +missed base pressure on. + +We missed base pressure on the Shuttle also. + +Not a big effect, but it is embarrassing that +you cannot get it right. + +But this was done primarily more in phase +C and D than in the phase A time period. + +We just kind of said plumes are going to be +about that much based upon data from other + +vehicles. + +And then making sure that it was not a design +driver or design stopper, if you please, that + +it wasn't going to be a problem that was so +big that it changed things so greatly that + +your performance wasn't adequate. + +And we had margins and everything. + +Anyway, we did some small scale testing. + +Phase B. + +What did we do on the Shuttle on phase B? + +We went into phase B with four major configurations. + +Three externally identical configurations +with swing wings. + +It was called the Triamese. + +And I think General Dynamics was the one that +proposed that one. + +They have all bought on another, and it's +hard to find out who is who any longer. + +But, anyway, that was one of the concepts. + +Very, very expensive. + +The swing wings, never really solved those +problems. + +Lockheed had a large single stage blended +body, kind of an HL-10 looking thing with + +a flat bottom, and then with a large external +tank around. + +And I couldn't find pictures of all this to +show you, but that was one that came in. + +And then the two-stage fully reusable with +both the first and the second stages being + +runway landers, a very favorite of Marshall. + +And then, the one that we called the stage +and a half where you're literally burning + +the first stage boosters and the second stage +engines at the same time with the external + +tank, we referred to that as a stage and a +half with parallel burn which is the current + +shuttle. + +But those are the things that we started phase +B in and did aerodynamic designs on all those. + +How did we do that? + +Well, we had gotten a little smarter. + +A lot of the Newtonian programs had now been +automated. + +It was still pretty much a flat plate kind +of a program, though, were you divided the + +vehicle up into a number of flat plates. + +And then there was some contractor in-house +wind tunnel test. + +NASA did some limited tests on potential problem +areas post phase B and pre phase C and D. + +That was a gap between the time we put out +an RFP, request for proposal, and the time + +that the contractors came back with a proposal. + +We had narrowed it down that it would be a +stage and a half. + +That would be what we would write the RFP +for. + +We developed a large wind tunnel test program, +developed a full aerodynamic database and + +heating database for that shuttle that was +there at that time that was delivered to the + +contractors that were going to bid on that. + +Integrated Vehicle. + +We used the USF stability and control datcom. + +Some contractor wind tunnel tests were done +and limited NASA testing and analysis for + +potential problem areas. + +And also we did a post phase B, full aerodynamic +database for that vehicle. + +Now, with that, what we're trying to do is +eliminate configuration changes if at all + +possible. + +And we accomplished that to some degree, but +the change to the tank and other changes came + +back in that caused us some delay. + +But it was minimized. + +Phase C and D, configuration was baseline. + +A big word here, make work changes only. + +Nothing has changed because it looks better, +works better. + +You've got to change it or it will crash. + +That's what we said. + +That's not what we did. + +We made some changes because they were nice. + +Theoretical aerodynamic techniques were employed +to ensure you never get to test the right + +Reynolds number. + +Henceforth, your boundary layer is a little +bit wrong. + +Plume effects, they've got to be corrected. + +So there was a lot of analytical work that +was done during that phase C and D. + +Let me say this. + +That area of our technology was really improved. + +A lot of dollars that went into that, Aaron's +courtesy, that the program probably didn't + +need to fly the shuttle. + +Now I tell him. + +I didn't tell him back then, you're right. + +[LAUGHTER] But, for the benefit of technology, +we did that. + +We pumped great money into CFD, great money +into method of characteristics. + +A lot of money into other techniques that +were there. + +And once more NASA goal was not only to do +that mission but to help technology. + +And the reason you can do CFD today was because +the dollars that the shuttle program pumped + +into that. + +Had they not pumped that in you would still +be adding up flat plates. + +[LAUGHTER] Aerodynamic variations and uncertainty +were developed for all aerodynamic coefficients. + +No other vehicle had really done that. + +You sort of did the best that you could and +said these are my aerodynamics. + +This is my normal force versus angle of attack. + +This is my side force coefficients, yawing +moment coefficients versus beta. + +And that said you would analyze that, give +that to the flight control system, give that + +to the structures people and they would put +their margins of safety in and look at it. + +We were quite concerned on this vehicle, especially +when it starts out at a 45 degree angle of + +attack. + +And sometimes during the supersonic and transonic +regime it transists down to a low angle of + +attack. + +Flow is separated. + +Some place in there it reattaches. + +It cannot always make up its mind. + +You've got to be able to control the vehicle, +even though we weren't intentionally maneuvering + +at that time. + +And so we developed these variations. + +If you go back in the tunnel three times you +get what? + +Four different answers. + +[LAUGHTER] And they're all very, very close. + +If you change facilities you get slightly +different answers. + +We had some Reynolds level boundary layer +kinds of problems between the wind tunnel + +and the full scale. + +And so these uncertainties were developed +for all the aerodynamic coefficients. + +Then this data was delivered to the GN&C people +where they make for sure that they can fly + +their system with the uncertainties. + +The CN betas, yawing moment coefficient with +angle of side slip, the control moment coefficients, + +the delta yawing moments and rolling moments +due to elevon maneuvers, where the errors + +on those, that the control system wouldn't +go berserk with any combination of those. + +The same with structures and with flight dynamics. + +Now, we're not living with those today. + +We did flight tests to reduce the variations. + +The astronauts put in PTI, pilot test inputs, +where they would do it a certain way and we + +would pre-predict those characteristics. + +Then we'd look at them post-flight. + +We would pull the aerodynamic characteristics +out with regression analysis techniques to + +say this is the aerodynamic coefficients that +had to be there for that maneuver to look + +like it looked. + +That, within itself, has some plus or minus +stuff because you can change stuff a little + +bit and it still looks pretty good. + +Those two then were combined and we had a +set of reduced aerodynamics. + +But today when you go to the aerodynamic data +book, which we hope to be able to get you + +copies of, it will have not only the coefficients +for all mach numbers, angles of attack, angle + +to slide slip, it will tell you what the uncertainty +as a function of mach number angle of attack + +is for that. + +And your system should be able to work with +all those. + +I want to mention this aerodynamic design +substantiation report. + +You won't be able to get a copy of that any +place that I know of but we're going to try + +to get a copy to Jeff for you, and it should +be available in your files. + +But what that did, that goes back in, and +for every coefficient, every angle of attack, + +how we arrived at that specific value and +those specific variations using both wind + +tunnel and flight test. + +A super document. + +Not pretty but an excellent technical document. + +And that was done during the flight test program +and afterwards. + +I thought we would stick up there the Wind +Tunnel Testing Program. + +That's primarily the backbone of the aerodynamic +database of the shuttle both for the Orbiter + +and the Integrated Vehicle. + +149 entry tests on the entry vehicle. + +79 heating. + +40 structural. + +You can add them up. + +Hours of wind tunnel test time 17,000. + +Aaron asked me how that compared with the +Apollo. + +As best I remember, we did about 4,000 to +5,000 hours on the entry vehicle on Apollo. + +However, Apollo didn't have all of those moveable +surfaces. + +Moveable surfaces are nice, do a lot of things +for you, but you've got to test and make sure + +they're there. + +And those were through various wind tunnels +throughout the country? + +Yes, sir. + +These were the best facilities in the country. + +Do they still exist? + +Far up and away, yes, sir, they still exist. + +The ones at Ames are still usable. + +The ones at AEDC are still usable. + +Unfortunately, those at Langley, even though +they're there and they work, because of funding + +constraints, Langley has a hard time bringing +them up and using them. + +And that's unfortunate because they have some +excellent facilities there. + +And we surely used them. + +In this Wind Tunnel Test Program, you can +find out in a special wind tunnel testing + +program summary. + +By the way, you can get this document pretty +straightforwardly. + +Ascent vehicle. + +A few less hours, and that's because you don't +move as many surfaces primarily. + +Heating. + +That's something to work on. + +If you want a good project to work on, how +do you take heating data in a wind tunnel + +on a small scale vehicle and make full scale +predictions? + +The reason that's near and dear to my heart, +they ran a test not too long ago and they + +still cannot match those two. + +A good PhD thesis. + +Maybe you can figure out how to do that and +how to do it right. + +A lot of scaling parameters that are used, +kind of like plumes. + +You're not sure which scaling parameter really +works, but there is slide test data, calorimeters, + +and there is fly test data and wind tunnel +data. + +It doesn't bother us that much because we've +got enough conservatism in the system and + +uncertainties that we know we're safe to fly, +but it does hurt your pride when you said + +hey, that heating rate should be 9 BTU's per +foot squared per second and the fly test data + +said it's not but 2. + +You might look good one way, you look bad +another way, but if I was looking for something + +to get my plow into and I was interested in +theoretical stuff, that's probably what I'd + +pick. + +Total Wind Tunnel Test Program, Aaron paid +for that out of his budget, by the way. + +It was less than $100 million. + +[LAUGHTER] In those year dollars. + +But it was an excellent program. + +Every test that was conducted was documented, +analyzed, and we can make that available. + +That concludes the things that I had to tell +you. + +And we hit that hour, just about right. + +Do you have any questions that you'd like +to ask? + +If not, I'll give you a test. + +Yes, sir. + +[UNINTELLIGIBLE PHRASE] How do we affect the +trim? + +[UNINTELLIGIBLE PHRASE] Hypersonics, and when +I say hypersonic, let me take it down to mach + +5, was probably the best at prediction that +we had. + +A flat plate which the belly of the orbiter +has a little bit of surface bending both in + +the pitch plane and in the yaw plane for stability. + +If you put a big sphere or segment of a sphere, +you could place the Orbiter on that and you'd + +say, hey. + +And I know a sphere or segment of a sphere +has stability. + +Now, the uncertainties turn out not to be +in normal forces or in even side forces. + +Pitching moment is the one that you tend to +miss the most. + +And sometimes you don't know if you have a +wrong pitching moment or a wrong center of + +gravity. + +They both precipitate a delta pitching moment +coefficient change. + +The big barn doors, we have that into the +system where we control not only a rate control + +system but an attitude control system. + +And so it takes, with a 70 square foot, it +just takes a small amount of change to correct + +any error that you might have in either CGR +pitching moment. + +Your control mechanism is with the big elevators +and also the body flap a little bit, if you + +want to use that. + +The reaction control system is a rate system. + +And I didn't mention that. + +And we intentionally put the reaction control +system in the wake of the vehicle, even though, + +for orbital maneuvering, we have jets that +are the forward firing end. + +But so much uncertainty in how that changes +the aerodynamics in a surface that is not + +a hard surface. + +And that interaction, you can change things +in such a way that you amplify it or reduce + +it. + +And so we elected not to try to grapple with +that problem and use just the aft jets, but + +it's just for a rate control system. + +End pitch, that's the distance that separated +that, and yaw on both sides, and in roll. + +[UNINTELLIGIBLE PHRASE] X-15 was a low angle +of attack airplane type configuration from + +mach 25 to mach 5. + +You're flying a spacecraft kind of configuration +where you basically roll about the velocity + +vector. + +You want to maintain that pitch trim and roll +about the velocity vector for cross-range + +in either direction. + +Now, when you begin transition because you've +got to be down here when you're landing, you + +pick the best place to do that. + +And the best place to do that is back in the +mach below 5 and, of course, above the subsonic + +regime. + +And we try not to have any maneuvers that +are required during that time period. + +Any time you're going from a totally separated +flow on the back of the vehicle to one that + +is now attached, separated flow cannot make +its mind sometimes. + +Does it want to be separated? + +Does it want to be attached? + +Not only the whole vehicle but even on small +pieces of the vehicle. + +And so there are uncertainties that come in +there. + +But that's the area. + +But you've got to be sure. + +And that's where we did a lot of our PTIs, +by the way, as we became more and more brave + +to get those coefficients. + +And the wind tunnel did a pretty good job +on them. + +Yes. + +[UNINTELLIGIBLE PHRASE] What you're doing +is changing the Newtonian flow now on my flat + +plate 70 square foot per surface. + +You mean the rear-end? + +The rear-end, the big end, yeah. + +Now I've got a normal force coefficient sine +squared to the angle. + +Then I just change the angle up and reduce +the forces on that, and that gives me a nose + +up. + +I bring it down. + +That gives me a nose down. + +It works beautifully. + +This is the body flap we're talking about. + +Body flap and elevators, yeah, both. + +Body flap and aft control surfaces. + +Yes, sir. + +You talked about the flight test portion of +the aerodynamics. + +What sort of planes were you using to do that? + +The flight test was the shuttle itself. + +After we safely entered and everything then +we designed these pilot test inputs to extract + +aerodynamic characteristics. + +The same technique that Edwards developed. + +And they did develop that, by the way, on +the X-15 and on other vehicles, too. + +And we used that same technique. + +We sent one of our men out and he spent about +almost a half a year learning all their techniques, + +brought that back, developed that and worked +with the astronauts very, very closely. + +They trained for those maneuvers. + +We extracted data for those maneuvers. + +We would change the aerodynamic characteristics +and not tell them what they are in the simulators. + +And made sure that we didn't get any difficulty +and made sure that the aero people could extract + +that data right and tell us how we changed +it. + +They all got good As. + +And it worked very, very well. + +[UNINTELLIGIBLE PHRASE] No, sir. + +We did that one. + +That was for the approach and landing test. + +But for the entry vehicle, no, those were +supersonic. + +Yes, and we did hypersonic. + +We're talking about tests that were done during +the flights. + +The first four flights were designated orbital +flight tests. + +And I think the PTIs actually continued well +after that. + +Yes. + +Actually, what this has given us, in terms +of a hypersonic database for a winged vehicle, + +is incredible. + +At first they were called pilot test inputs +because the pilots were doing them automatically. + +And then I remember some of the pilots were +saying you've got to do it very precisely + +and so we really have got to be concentrating +on that. + +And there are so many other things we have +to concentrate on. + +Could we possibly computerize this? + +And so I don't remember which flight they +started doing that, but at that point the + +PTIs became known as the program test inputs +rather than the pilot test inputs. + +You basically put in a little pitch up, pitch +down and see how it affected the roll and + +the yaw and all these cross-coupling things +at lots of different mach numbers. + +And, over the course of a bunch of different +flights and a lot of different PTIs, it really + +built up the aerodynamic coefficients at all +these different mach numbers. + +You might say a little bit about how we collected +hypersonic test data in wind tunnels. + +I mean it's not like you can just have a fan +going and produce a mach 20 airflow for 20 + +minutes and you can play with your little +thing. + +Hypersonic testing was done primarily at the +Ames Research Center three and a half foot + +facility. + +We also did some up at Calspan, also used +some of the Langley facilities, but the real + +workhorse was this three and a half foot hypersonic +tunnel. + +And basically you would have the air coming +through the tunnel at the required conditions. + +You would put the model of the vehicle, which +is usually a 1.5% to 3% model in the facility. + +You have what is called a six component balance +that fits into the model. + +That is a strain gauge relationship. + +It gives you force and moments in both directions, +or forces in both directions and some difference + +between the gauges so you can pull the pitching +moments and the yawing moments and the rolling + +moments out of that. + +You reduce it based primarily upon dynamic +pressure or you say CN is equal to the normal + +force divided by QS, the dynamic pressure +times a reference area. + +Standard aerodynamics, but once more a language +kind of thing where if you're in gas dynamics + +and not aerodynamics sometimes you don't get +back over to those coefficients. + +By the way, in that same document all of those +terms are defined pretty well. + +But you measure those with a balance. + +Then the question happens, well, I wasn't +at full scale Reynolds number. + +And then that's where you come up with your +theoretical techniques. + +And you come back in and you look at it and +you see that the boundary layer and the Reynolds + +number corrections theoretically make a very +little bit of difference. + +And then you go through today the CFD programs. + +You say it gets about the same answer. + +You go back to the flight test data and it +gets about the same answer. + +Basically, what you conclude is wind tunnels +do a super job hypersonically for this kind + +of a configuration. + +Now, it did good on the Apollo, it did good +on the Gemini, it did good on the Mercury + +and it did good on the Shuttle. + +Give me that configuration and I'll tell you +what the hypersonic aerodynamic characteristics + +are. + +I can tell you in phase A, and it's not going +to be too much different at the end of phase + +B. + +And maybe you don't want to hear that because +maybe you were going to do great things in + +the hypersonic area. + +But on a blunt body, which is what we're talking +about, it does a super job now. + +X-15, low angles of attack flying like an +airplane, a different story completely. + +[UNINTELLIGIBLE] configuration. + +No, I wouldn't want to use just Newtonian +to predict the aerodynamic characteristics + +hypersonically of that vehicle. + +On the other hand, I wouldn't want to fly +it there either. + +It would burn up. + +Blunt body is good. + +98% of the energy goes into the shockwave. + +98% of the energy goes into your vehicle when +you're flying low. + +A manned entry vehicle enters the earth's +atmosphere. + +You're going to be flying something like a +segment of a sphere or at worst a right elliptical + +cone. + +And Newtonian works good on that one, too, +by the way. + +We wind tunnel tested those for different +configurations. + +That gets your L/D on up to a 1.75 rather +than 1.5. + +Yes, sir. + +Why couldn't any sort of straight winged configuration +make the cross-range requirement? + +The cross-range requirement is primarily angle +of attack oriented. + +The relationship between the CG payload in +and payload out is a pretty good change. + +And, if you had a straight wing, your straight +wing cannot be placed in such a way that it + +trims subsonically and trims hypersonically. + +Now, it can,at higher angles of attack with +less L/D, you can make it work. + +But down at 45 degrees you end up with a delta +wing configuration. + +Does that answer your question? + +And that's a good exercise, though. + +But you can go through it on a couple of sheets +of paper and say ah-ha. + +Because hypersonically you've got that CG, +you've got your CP, you know where it has + +got to be placed, you get down to low angles +of attack, you know where your CP is for that + +body, you know your CP is up at the quarter +card and you know you've got 4.5 CGs. + +It doesn't quite work. + +It takes a delta to do that. + +So it was more CG related than heating? + +Yes, sir. + +Although, the one that we mentioned, the 200 +nautical mile cross-range with a straight + +wing, Langley did some tests on that, even +at high angle of attack. + +And right in where that straight wing ties +back into the fuselage had super high heating + +rates. + +But we could put little fillets in there and +overcome that heating particular thing. + +But, if you're going to go real fast, delta +wings look better. + +[LAUGHTER] All right. + +Yes, ma'am. + +When you were doing all this aerodynamic analysis, +did you consider a perfect surface, or did + +you also do tests or analysis on what if the +TPS fails? + +Good question. + +First of all, we have an external insulator. + +And Bob Ried will talk to you about that, +and Tom Moser probably has too. + +Which meant that our main aluminum surface, +which we want to keep quite cool, is different + +than the one that we initially designed. + +We went back in, made models that simulated +those differences, made calculations that + +simulated those differences. + +They were very small corrections that needed +to be made. + +Then the other question that you had was suppose +you lose a piece of TPS? + +Which we did. + +We've lost some chunks of TPS early in the +program. + +And you cannot do much testing on that because +it's so little bitty and it's like a greased + +pencil kind of a thing. + +But you go back in. + +The first approach is we take some maximum +things. + +The pressure cannot be greater than total +and it cannot be less than zero. + +And so let's put those deltas into that area +and into a nice area around there and see + +if it makes any difference to the aerodynamic +coefficients. + +And they're quite small and so we feel quite +comfortable with that. + +Now, from a heating, a different answer. + +But, from an aerodynamic standpoint, does +it affect the aerodynamics? + +We scope it in that way. + +It's a pretty small area. + +Yes, sir. + +Where was the greatest risk on the aerodynamic +design? + +During the first flight, was there anything +you were particularly concerned about? + +Oh, yeah. + +[LAUGHTER] Getting it right. + +I guess my biggest pucker factor is in the +transitional phase. + +I'd just seen so many things go wrong transonically +that transonic wind tunnels miss. + +It's a dynamic situation where you're moving. + +And that was, personally, my greatest concern, +did we get that right? + +We did everything we could. + +And it turned out that we did a good job, +but I worried about that more than anything + +else. + +Launch vehicle. + +Primarily did we get the structural loads +right and did we put enough margin in? + +We did not use uncertainties in the pressure +distributions. + +Couldn't really figure out how to do that. + +We had to have balance loads. + +And if you said my CP can be higher or lower, +do you put it higher over the whole vehicle + +or higher here and lower there? + +And then you've got unbalanced loads. + +But we did measure the wing bending moments, +wing shears, wing torsion and also the attached + +loads in those. + +And so we put some uncertainties on those. + +And Tom has already been here. + +I don't know if he mentioned how they tried +to handle those. + +But at least they had some of those things. + +But we never figured out how to put uncertainties +and pressure distributions and still be able + +to get all the balance loads for NASTRAN. + +Maybe one of you all are sharp enough to figure +out how to do something like that. + +But that was the one on the ascent, had we +adequately covered the uncertainties in pressure + +distributions with the way that we accomplished +that by the uncertainties in the bending moments, + +torsion and shear? + +Let's take a couple minute break and then +we can resume with questions. + +I am going to go down to my office and get +one or two things which I think will be interesting + +that we can also talk about. + +Take a minute or two. + +Instead of one configuration, you've got one +configuration times 5 degrees, 10 degrees, + +minus 5 degrees. + +These split down the middle. + +The same way here, body flap. + +You've got one, two, three, four, five times +five. + +You've got 25 different configurations versus +one. + +And so it means more testing, but you're using +the same facility. + +It just means more hours of wind tunnel time, +more hours of plotting and looking. + +Say a few words about how you did the systems +engineering or the systems integration between + +the aerodynamics and the flight control system +[UNINTELLIGIBLE PHRASE]. + +All right. + +Let's take flight control system. + +We, in our division, were responsible for +aerodynamics and flight dynamics. + +And flight dynamics wasn't very well defined. + +The Avionics Division was responsible for +the GN&C system control system and also flight + +dynamics. + +So, you've got to work together. + +And you're going to get in one another's bailiwick. + +That's part of good systems engineering. + +You're going to do what the other fellow is +going to redo, and he's going to do what you're + +going to redo. + +But our responsibility was two-fold. + +One is we had to have the right aerodynamic +characteristics. + +But, before we had the right aerodynamic characteristics, +we had to have a configuration that should + +be able to live with a GN&C system. + +The way we accomplished that is Ken Cox, is +Ken going to be here with you? + +No, OK. + +Ken Cox was head of the Avionics and GN&C +System. + +He gave us a functional GN&C system. + +It didn't have all the strings in it, didn't +have all of the relays and all the stuff there, + +but if we gave it a command to change that +we knew how much it would change and how long + +it would take it to change. + +An elevator position as a for instance. + +And so that was called a functional GN&C system. + +It did the right functions but it didn't do +it the same method that the real GN&C system + +did. + +We would take our aerodynamics and see that +it would work. + +And we would be able to make the maneuvers +that were required. + +And we would analyze it. + +Ad we would be pretty satisfied that with +those aerodynamics and with the variations + +that we were OK. + +But that didn't say the system was OK. + +That just said that we had a pretty high probability +of making it work. + +Then we sent that aerodynamic database. + +And all this is happening not ship it, throw +it over the fence, but over a period of time + +we sent them the aerodynamic characteristics +with the variations. + +And then they beat it bloody flying everything +they can think of with their GN&C system. + +Fortunately, that worked out pretty well. + +He would pick up a few things, but not anything +major. + +And, by the way, this is the only vehicle +I know that happened that way on the Orbiter. + +We didn't have any major configuration changes +that we had to make once we got well into + +the program. + +It stayed the same. + +[UNINTELLIGIBLE PHRASE] That's right, yes. + +And that was true. + +That whole thing, not only the GN&C system +but the hydraulics is when you give it the + +command, when you say I want a delta theta +so much or delta E of so much, that it takes + +it about a quarter of a second to get there. + +And that's a long time on a lag time when +you pile all those things end to end up. + +Now, structure is much the same way. + +They gave us load indicators where they said +we can take so much wing shear, so much wing + +torsion, so much wing bending, so much punch +loads into the tank from the attach point + +in the front, so much punch loads into the +tank on the backend, SRB and we have all the + +gimbling. + +That's where we're doing the flight performance +calculations, through the wind shears and + +the wind gust. + +And we assure ourselves that we don't violate +any of the load indicators. + +But that does not say the vehicle is safe. + +Then GN&C flies that one through that and +gives all those conditions back over to the + +structures people, and they analyze the hound +out of it. + +They look at all the cracks and crevices. + +And, if you have people that don't have a +cooperative spirit, it will not work. + +It just doesn't work. + +So, you've got to learn how to get along with +your buddies over on the other side. + +Don't build your fiefdom up that your wall +is so big and you control your own destiny + +because you don't. + +And we had a super group of people to work +with. + +And, to me, that's what really made it work. + +The same thing on heating, by the way. + +They would give us heating indicators and +we would fly it because that was a little + +more straightforward where they would give +us the Q dot locals to Q dot references. + +And we would look through all the Q dot references. + +And we'd give them all the final set of trajectories +and they would analyze it in detail. + +But I look at it as here is a problem and +I can work it like a piece of pie and go on + +this problem, go all the way down to the center, +then go over and eat this piece and this piece. + +It doesn't work that way. + +You start around the edges and you cycle in +on it. + +You eat all the pie, but you accomplished +it around the edges first and work out your + +bigger problems and then get down to the smaller +problems. + +Bass, I think the important point, too, is +that no matter what system you work on, whether + +you work on the Apollo or you work on the +Shuttle or whether you work on the new CEV, + +you're going to basically have to go through +the same process. + +It may be simpler or harder but you're going +to have to go through the same process. + +Absolutely. + +Yes, sir. + +You said there was no major configuration +changes like around the program, but is there + +anything that you felt you were kind of stuck +with like I wish we could have changed this? + +Like not having the OMS pods stick out in +the back like that? + +What that a problem for aerodynamics? + +No. + +We lost the increased drag a little bit, but +not enough to hurt anything. + +And aerodynamics, it didn't bother me any +that my L/D went down by 0.001. + +But now the fellows that were flying it, they +got in there, they said I can still go around + +the hack and I can still do all the things +I want to. + +But all that was done. + +And once more, systems integration, you've +got to include the crew. + +GN&C system, it doesn't bother them in aero, +it doesn't bother them in structures, but + +you've still got to fly. + +And Dr.Gilvarry said you don't want the pilots +talking bad about your airplanes in the bars + +so keep your crew happy. + +[LAUGHTER] But, to answer your question, no, +not really. + +To meet the requirements, it's going to look +pretty much the same. + +If I designed it today, OK, let's go back, +the same requirements now. + +If you give me a different set of requirements, +it's not going to look the same. + +Bass, some people wanted to put some canards +[UNINTELLIGIBLE PHRASE]. + +canards, that's not a joke. + +That was done, but it was a big argument. + +A canard is an aerodynamic surface part of +the center of gravity. + +And the beneficial part, let me tell you the +good parts about canards. + +canards, subsonically, I can give a pitch +up moment and increase my lift. + +If it's on the aft of the vehicle when I give +a pitch up moment, I decrease my lift. + +So, canards are wonderful. + +But what canards do is it fouls up the flow +over all of the rest of your vehicle. + +And so, back to here, I've got one configuration. + +Unsteady aerodynamics. + +Heating. + +Fixed configuration. + +I put a canard out there. + +Now I've got two more configurations, three +more configurations, four more, five more, + +six more. + +And it does a lot of grief with vortexes and +stuff like that. + +Now, if you had to have it, you have to have +it. + +Concorde had to have it, but that didn't mean +that Shuttle had to have it. + +It operated fine without canards. + +I sure wouldn't put canards on there, if we +had another shot at it. + +Yes, ma'am. + +Would it be easier, faster or cheaper to design +the Shuttle, the Orbiter [UNINTELLIGIBLE PHRASE]? + +You ask good questions, young lady. + +[LAUGHTER] Yes and no. + +With the tools we have and the foreknowledge +that we have, having been there before, absolutely + +yes. + +And I don't want to be negative, but you don't +have the cooperative spirit going on that + +you had then. + +I don't know why either. + +The young engineers are sharper, no ifs, and +or buts. + +You all know a whole lot more than I ever +knew, but you don't get along as well. + +[LAUGHTER] This is mine. + +I don't need you here. + +I don't want you here. + +Get out of here. + +I'm going to do it my way. + +And that's just an observation I made. + +It might be that my knothole is too restricted. + +But it goes up to pretty high management, +too. + +Not just at the working level. + +A second thing is they asked me to come in +and consult with them. + +And they had lost technical capability. + +Didn't use any engineers much after a certain +time on the Shuttle. + +And then, after the last accident, they had +to bring the engineers in. + +And they said I've never looked at that and +I'm on the payroll. + +The capability was greatly lacking, and so +we developed some ways to bring them to speed + +in about a year and a half period of time +which happened. + +Observation. + +By the way, I was pleased that you all got +to class on time. + +I told management to send them to ethics school. + +Now, if there is a meeting and you tell somebody +you will be there at that time, you be there + +at that time. + +If you tell somebody you will make a deliverable +at that time, you make a deliverable at that + +time. + +Be a man or woman of your word. + +And I found that lacking. + +I don't know that ethics school helped too +much that we sent them all to. + +Well, it did, too, because the second day +of class there were, I think, ten of them + +late. + +And he sent them back and wouldn't let them +in the class. + +[LAUGHTER] But learn to get along with folks. + +They are your friends. + +They're your buddies. + +They are going to be there for a lifetime. + +And, yeah, you're going to have some grief. + +And, yeah, he will give you some headaches +or she will give you some headaches. + +But you're all on the same team, and work +hard towards that. + +I know you've got to grit your teeth and spit +sometimes, but that's major. + +And that didn't cost you anything. + +About the wind tunnel testing, firstly, could +you have reduced that now with CFD? + +And, secondly, you showed there were several +hundred tests. + +Yes. + +And several tens of thousands of hours. + +Yes. + +Does that mean each test ran for several hundred +hours? + +Some tests ran for hundreds of hours. + +That was the total number of hours for all +those tests, not a per hour basis. + +But, yeah, there were some hundred hour tests +that went on. + +To answer your question, does CFD reduce the +number of wind tunnel hours? + +Three areas that we're working in right now. + +One reason is to bring the engineers up to +technical speed where they can stand up and + +be counted. + +And you can ask them a technical question, +they can give you a technical answer and say + +this is my analysis and this is how I got +that. + +To do that we recommended back to Johnson +Spacecraft Center that you better get your + +engineers knowing how to do wind tunnel tests +and you've got to get them to know how to + +make the calculations to run these programs. + +You've got to be able to do all that. + +That's your integration contractor. + +They need to have that capability. + +And they've done that and they really came +up to speed. + +In the midst of that, they've also increased +their CFD capabilities. + +And I'm very envious of what you can do with +CFD. + +However, it hasn't decreased the amount of +runs that they're requesting. + +It's increasing the amount of runs that they're +requesting because they will do this little + +bitty analysis and here is the cable tray +going down that, and they'll say does it go + +sonic under the cable tray? + +Well, I don't know. + +What does the wind tunnel test say? + +Well, we just have a data point here and a +data point here and our CFD shows that it + +can go sonic under there, we need to test +that to make sure that's there. + +[LAUGHTER] And so it could but I don't think +it will. + +I think the better your tools get you want +to make sure they're right. + +Now, one day I think yes, that's going to +happen, but right now there is still a lot + +of question, even in the CFD-er's mind, am +I really right? + +And they've always been accused of they can +tell you what the right answer is if you give + +it to them. + +[LAUGHTER] And that's really not true any +longer. + +That was for a number of years. + +But that CFD is so great. + +And they used overflow, by the way, is the +one that's primary to the big workhorse right + +now, and it does a super job. + +Was there a question? + +All right. + +Any other question? + +I would like to address the question that +was asked about [UNINTELLIGIBLE PHRASE]. + +Let me not talk necessarily about the Shuttle, +but let me talk about Apollo for a moment. + +And I mentioned it before. + +In Apollo, we went to the moon with a single +string avionic system. + +We had one IMU, one computer on the Command +and Service Module. + +We had one service propulsion system to get +you out of lunar orbit or to get you into + +lunar orbit. + +And I think today it would be very difficult +to do that. + +I think you're probably going to have to have +multiple strings. + +You're going to have an escape system. + +I think, in that context, it may be more difficult. + +I do think the tools you have today will make +it easier, but I do think what we know today, + +just like Bass said on understanding a little +bit about the aerodynamics, you want more. + +I think in some respects -- My comment is +that the next time we go to the moon we're + +going to find out how hard it really was because +I do think it's going to be hard to do. + +At least that's my personal feeling. + +And I think a lot of people agree with me. + +One of the toughest decisions we ever made +in the Space Program, and Bass and I were + +talking about it at breakfast, is when we +decided to do Apollo 8. + +Apollo 8 was probably the most fantastic mission +that we ever came up with. + +That was the first time we left the influence +of earth's gravity, we went into orbit around + +the moon and we got out of orbit of the moon. + +Now, we didn't land on the moon but did everything +we had to do for the first time. + +And I think that was probably the boldest +decision that NASA and the government ever + +made. + +Again, I look back, and I'm not sure how we +would make that decision today. + +It was pretty tough. + +And, of course, one man led that attack, George +Low who was Manager of the Apollo Program + +Office at Johnson Space Center, then became +Deputy Administrator and then became President + +of Rensselaer Polytechnic Institute. + +But that was really a fantastic project. + +I will comment on the programs that I worked +on. + +Aerodynamics on Dyna-Soar, which was a defunked +Air Force manned spacecraft program. + +I worked on Mercury, Gemini, Apollo and Blue +Gemini. + +And each time I would go onto the next program +and learn more, I would say we sure were lucky. + +[LAUGHTER] When I was telling you about these +new young engineers now that are up to speed + +where they didn't want to say anything. + +Now that they're crunching numbers, they got +a lot of criticism for the way we did it. + +[LAUGHTER] And rightfully so. + +A lot of capability that is there. + +And you're going to have more capability today +than you had yesterday, more capability on + +the next program than you had on the last +program. + +You're going to find some things to do and +be able to do it better than the last program + +was done. + +That's both good news and bad news. + +Bad news is it will cost you more to do it +and the good news is it will be done a whole + +lot better. + +All right. + +Any other question? + +I thought it might be interesting, just to +make sure you really have an understanding + +of what the Shuttle has to do, to sort of +take them through the entry. + +And maybe, Bass, you'll make some comments +about the aerodynamics and I'll talk a little + +bit about the operations. + +You're in orbit a couple hundred miles above +the ground, and the first thing that you do + +is basically put the Orbiter, after you get +everything stowed and ready for entry, so + +you're essentially going backwards, face to +the ground. + +And you burn the OMS engines. + +And just, in terms of redundancy, we've got +two engines. + +You can cross-feed the fuel that is inside +the OMS pod. + +You can cross-feed from one side to the other. + +So, even if you lose one OMS engine, you can +still do a de-orbit burn just on the other + +engine. + +Of course, you will have to turn a little +bit so that you can burn through the CG. + +If you lose both OMS engines, you can cross-feed +the propellant into the reaction control system + +aft jets and you can come back using those. + +And if you're having a real bad day and you +run out, well, you know, you might have a + +fuel leak, for instance, and so you don't +have enough propellant back there. + +Actually, there was a procedure where you +then would flip over and burn the remainder + +of your forward RCS propellant to just slow +yourself down as much as you could. + +We never had to do that. + +In fact, I don't think we ever lost an OMS +engine. + +But we practice all these things. + +Anyway, the point is, one way or the other, +you slow yourself down. + +Here is the earth and here is your orbit. + +This is grossly out of scale. + +You realize that on this scale your orbit +is actually about like that. + +In any case, you do your burn just enough +to lower your perigee just about two ground + +level. + +And now you're essentially in free-fall. + +I mean you're in free-fall in orbit, but now +you're gradually getting closer to the earth. + +And so what you do is you now flip over and +you put yourself in a position where when + +you actually hit the top upper reaches of +the atmosphere -- And about 400,000 feet is + +what we call entry interface. + +And, actually, the flight control system changes +at that point and the computer actually goes + +into a different mode. + +So, at this point, you're now at a 40 degree +angle. + +And, as Bass said, that gives you your blunt +surfaces approaching. + +And basically the sensors feel the deceleration. + +And that's really how you know where you are +in the entry. + +You sense the deceleration. + +That tells you what the dynamic pressure is. + +During the early part of the entry, all of +your control is by the reaction control system + +because you don't have enough dynamic pressure +on the aerodynamic surfaces to be effective. + +As you get down further and further into the +atmosphere -- Let's see. + +I think the number that comes to mind is ten. + +I assume that's ten pounds per square foot +dynamic pressure. + +Yes. + +Is when the ailerons become effective. + +And so you have what is called a blended control +system. + +The first thing that you can do is actually +control your roll, and so you disable the + +roll jets and you enable the ailerons. + +But the pitch and the yaw is still controlled +by the RCS. + +And the critical thing, like Bass was saying, +is you've got to keep your angle of attack + +constant with respect to your velocity vector +because your aerodynamic heating depends on + +that. + +If you get down to too low an angle now you're +going to heat the surfaces, the upper part + +of the Orbiter and you're going to burn up. + +You're controlling your angle around the velocity +vector. + +And now you can move about that. + +You have a lift vector. + +And now the whole name of the game, because, +remember, this is a glider. + +And so energy control is what is absolutely +essential to make sure that you're going to + +end up at the threshold of the runway at about +-- You said we were aiming for 150 knots. + +We never actually made it. + +Actually, about 200 knots was the touchdown +speed. + +But pretty good anyway. + +We got close. + +At every phase of your entry, knowing your +energy and controlling it is critical. + +For instance, for whatever reason, if your +burn didn't go right and you think you're + +going to be short of the runway, we notched +down the angle of attack just a little bit. + +I think about 38 degrees was about the lowest +you could safely go. + +And you keep your lift vector. + +You basically would fly the entire entry with +your lift vector going away from the earth, + +and that maximizes your range. + +But you actually target the entry so that +you have more energy than you need because + +it's a lot easier to bleed off energy than +somehow to get it back, especially when you + +don't have any engines. + +What you normally do then is you will basically +do a roll maneuver. + +And you'll be rolling so that your angle of +attack, with respect to your velocity vector, + +is always 40 degrees. + +But essentially you're rolling around the +velocity vector so you can now point your + +lift over to the side. + +And, for instance, if you didn't have enough +propellant when you were burning, and so now + +you actually have too much energy, what you're +going to do -- Or, for instance, if you have + +a lot of cross-range that you have to make +up, you could spend your entire entry over + +on your side like this. + +And, in fact, there was even a case which +we would simulate if you have an under-burn, + +now you have too much energy and you have +to get really get rid of a lot of energy, + +you could actually roll 180 degrees. + +And that would be pretty sporty. + +[LAUGHTER] Again, nobody has ever had to do +that. + +But we did simulate it. + +And I don't know what you would make of the +aerodynamics coming in, but the point is you + +have a basic design that you're working with +and then you try to develop operational procedures + +to make the system work in as many contingencies +as possible. + +Anyway, that's the deal. + +You basically are rolling around the velocity +vector to control both your energy and your + +cross-range. + +Let's see. + +Then at 20 psf the elevons actually get pitch +affectivity, and so you disable the pitch + +jets. + +And now both the pitch and the roll are controlled +by the elevons. + +The vertical stabilizer, as you can see, is +in the shadow. + +And so, actually, you don't get yaw affectivity +out of the vertical stabilizer until just + +about transonic and subsonic, when you actually +do the final pitch-over to get ready for going + +into the heading alignment circle. + +And that's why sometimes, if you've seen pictures +of the Shuttle as it approaches the landing + +at Kennedy Space Center, you will see little +plumes come out the side. + +And that's the yaw jets and the RCS which +are still firing, because it's still supersonic + +when it gets over the Space Center. + +And, if you're on the ground, you can actually +hear this double sonic boom which is pretty + +impressive. + +And I guess you get one from the front and +one from the back of the vehicle, so it's + +a boom boom and then it goes around. + +And then, of course, you hit the atmosphere +at mach 25. + +And so you're going through this entire aerodynamic +regime down through hypersonic, supersonic, + +transonic, subsonic. + +And I remember, Max Faget gave us a little +talk about how the aerodynamic coefficients, + +I mean you were talking about them, but they +change at different mach numbers, right? + +Oh, yes. + +And we mentioned this before, you know, why +you really need a fly-by-wire system on this + +vehicle, because the control laws that you're +using to do a roll maneuver at mach 15 are + +different from doing a roll maneuver at mach +8. + +These program test inputs, you can hardly +see them. + +I mean you really didn't feel them. + +They were just a couple of degrees that you +would move the stick, you know, just little + +things. + +But that collected enough data to get a much +better determination of these coefficients. + +You're very sensitive to things like beta +angle. + +Probably about two degrees. + +If you go off more than that. + +Actually, when you read the detailed description +of the loss of Columbia, when they had a penetration + +of the forward edge of the wing, that disturbed +the airflow. + +And so the control system was fighting a really +valiant fight to keep Columbia on target. + +And they could see that on the ground. + +There was more aerodynamic surface activity +and the RCS jets kicked in. + +In the end, of course, you run out of control +authority and the vehicle eventually diverged + +and it actually broke up aerodynamically. + +It was not an explosion. + +It just broke up aerodynamically. + +The hot gases in the wing were disrupting +the airflow and eventually the wing was slumping, + +and so things were just getting worse and +worse. + +And I don't know exactly what went first. + +Pieces were falling off along the way. + +The same thing if you read the analysis of +the Challenger accident on a second-by-second + +basis, you'll see the main engines were adjusting +their thrust and trying to keep it -- The + +system was really working hard just doing +what it was supposed to do. + +Essentially the flight control system was +trying to keep it within the control boundaries, + +and eventually it ran out of muscle because +of the other failures. + +And once you go to a bad beta angle or angle +of attack the vehicle breaks up aerodynamically. + +Bass, you might say a word about the aerodynamic +coefficients and which ones were the hardest + +to determine and how big [were the errors?]. + +OK. + +Basically, aerodynamic coefficients are normal +forces, side forces, rolling moments, yawing + +moments, pitching moments and those that change +that like elevators, body flaps, rudders and + +speed breaks. + +The coefficients, the biggest variations are +in the low supersonic to transonic speed regimes + +primarily in the control variables. + +The biggest ones were just before transition +or any time that the elevators were in an + +up position where the flow couldn't quite +decide whether to be attached or separated. + +And so you want to avoid that. + +Digging down, not very much variations in +those at all, but coming in the up position + +pretty big variations in the rolling moments +and yaw moments due to those. + +And we tried to avoid those, of course, and +henceforth with the CG location. + +But those were the ones that probably were +the toughest and we tried to stay away from. + +Overall, hypersonics right on, subsonics second +best, transonic the most difficult, low supersonic + +kind of in between there. + +The coefficients, it's hard to talk about +them on a percentage basis because CM is zero + +and the delta CM is an infinite percentage +so you cannot really talk about them on a + +percentage basis. + +But, when you look at the plots like CM versus +alpha, very small variation after we got through + +with the flight test program. + +Before we got through the flight test program, +we probably cut the variations in half on + +things like pitching moments, yawing moments +and rolling moments. + +We did better than that on the pitching moments, +yawing moments and rolling moments due to + +elevator positions when they were local angles +of attack. + +And those were cut quite significantly with +the PTIs. + +But still, even today, you don't just have +one coefficient at one angle of attack, one + +angle of side slippage. + +You evaluate that one plus the variation that's +about it. + +And I remember one of the big activities in +the simulators before the first flight. + +They would have the test flight crews, who +were going to make these flights, do flying + +entries. + +And they would actually vary the aerodynamic +coefficients. + +And, if you put in a big enough variation, +three sigma and all of the parameters and + +they went in the wrong direction, you could +always make it impossible to have a successful + +entry. + +And so it was a real question where the managers, +and Aaron, maybe you have something to say + +about that, you and Chris Kraft had to really +make the decision when you knew enough and + +when you could fly safely. + +You're going to hear Chris Kraft talk shortly. + +But I remember after we landed the first mission +there were a lot of people saying that the + +Shuttle wasn't going to work, all the tiles +were going to come off. + +The flight control system was a big issue +because of the aerodynamics. + +The flight control system, the aerodynamics +wasn't going to work. + +I don't know if you've ever been to the Johnson +Space Center and to the Control Room, but + +I was sitting at the consul with Chris Kraft +and he got on the Net and said -- Because + +there was a lot of criticism. + +A lot of people wrote letters that the Shuttle +would crash and wasn't going to make it. + +And he got on the Net and said we're infinitely +smarter today. + +And I guess that summarized it, we were infinitely +smarter and we did design a good system. + +And I think that about summed it up, that +we were infinitely smarter. + +Any more questions? + +Yeah. + +Actually, it's an operational question. + +OK. + +I'm just wondering if the entire crew is trained +on the whole landing procedure. + +No. + +We have two pilots just like in any airplane. + +Some of the people who flew center seat as +flight engineers were trained pilots. + +And I would have been quite comfortable if +they had landed the Shuttle. + +But how many failures do you prepare for? + +We have two people onboard who are trained +to land. + +I always thought to myself, we also have this +auto land software which nobody has ever used, + +but if somehow all the other six people were +incapacitated and it was just me, I would + +push the auto land sequence. + +[LAUGHTER] And all you have to do is put the +gear down manually, and I know how to do that. + +But landing the Shuttle is really very complicated. + +And they train hundreds and hundreds of hours +in the simulator. + +Some day we could spend a whole session talking +about the Shuttle Training Aircraft. + +It is one thing to land in the simulator, +but nobody has ever died in a simulator, number + +one. + +And, number two, you're looking at a TV screen. + +You're not actually looking out at the runway. + +You don't feel the bumpy aerodynamics. + +And so they developed a Shuttle Training Aircraft, +which is the Gulfstream II very heavily modified. + +It's actually a flying simulator. + +Your final approach, because your L/D on this +vehicle, I don't know what it is exactly, + +is about five maybe. + +I think five at best, yeah. + +You're coming in at about a 20 degree approach +angle, which may not seem like a lot. + +But a commercial airplane comes in at about +three degrees and the problem is, you take + +a regular airplane, and you point it down +at a 20 degree angle,and your airspeed is + +going to go above your redline. + +So you've got to make enough drag to simulate +the Shuttle. + +There's computers inside this Shuttle training +aircraft. + +The left seat is set up to be just like the +Shuttle cockpit, and when the pilot makes + +the maneuvers, it basically goes back into +the computers and they work the flight control + +system of the gulf stream, to make the gulf +stream fly like the Shuttle. + +The only way that they can produce enough +drag to make it go at a constant speed at + +a 20 degree angle, is you have full speed +brakes your gear is down, you have thrust + +reverses you run your engines in reverse, +after your on the runway to slow youself down. + +On the gulf stream, they run their engines +at 90% reverse thrust while they're flying + +in the air. + +It's an extraodinary vehicle. + +I've flown in the center seat just to sit +in it and you may be flying on this angle + +but it looks like your flying like this [LAUGHTER] +It's really extraodinary. + +Just one thing to remind you,a week from today +we've asked for the initial report outline + +plus some reference material. + +What we want to get a sense of what is your +plans, what's the scope of what you're going + +to be looking at, what are you going to deal +with and I hope by this time that you've located + +some reference materials you're going to be +using. + +We'll be sort of spiralling in on this so +the idea is we'll take a look at what your + +plans are and then we can work together if +you have some questions or having difficulties + +this gives us some opportunities to talk about +it to make sure you're on the right track + +so you'll be doing something that you can +be proud of, that you'll actually learn something + +from, so that's due a week from today. + +It would be useful for me to have those electronically +so that I can send them to Professor Cohen + +for him to look at. + +I am happy to accept hard copy as well but +I want them electronically Any questions? + +Have a good weekend. \ No newline at end of file diff --git a/3ejfkMHr_DE.txt b/3ejfkMHr_DE.txt new file mode 100644 index 0000000000000000000000000000000000000000..f177f7c3b21c9aaafd994e6f03b29d68c4adb8f2 --- /dev/null +++ b/3ejfkMHr_DE.txt @@ -0,0 +1,7235 @@ +align:start position:0% + +today is going to be one of the more + + align:start position:0% +today is going to be one of the more + + + align:start position:0% +today is going to be one of the more +difficult lectures of the term so put on + + align:start position:0% +difficult lectures of the term so put on + + + align:start position:0% +difficult lectures of the term so put on +your thinking caps as they say in + + align:start position:0% +your thinking caps as they say in + + + align:start position:0% +your thinking caps as they say in +Elementary School uh the topic is going + + align:start position:0% +Elementary School uh the topic is going + + + align:start position:0% +Elementary School uh the topic is going +to be What's called the + + align:start position:0% + + + + align:start position:0% + +convolution the convolution is something + + align:start position:0% +convolution the convolution is something + + + align:start position:0% +convolution the convolution is something +very peculiar that you do to two + + align:start position:0% +very peculiar that you do to two + + + align:start position:0% +very peculiar that you do to two +functions to get a third function it has + + align:start position:0% +functions to get a third function it has + + + align:start position:0% +functions to get a third function it has +its own special symbol F of + + align:start position:0% +its own special symbol F of + + + align:start position:0% +its own special symbol F of +T asterisk is the universal symbol + + align:start position:0% +T asterisk is the universal symbol + + + align:start position:0% +T asterisk is the universal symbol +that's used for + + align:start position:0% + + + + align:start position:0% + +that so this is a new function of T + + align:start position:0% +that so this is a new function of T + + + align:start position:0% +that so this is a new function of T +which Bears very little resemblance to + + align:start position:0% +which Bears very little resemblance to + + + align:start position:0% +which Bears very little resemblance to +the ones F of T that you started with uh + + align:start position:0% +the ones F of T that you started with uh + + + align:start position:0% +the ones F of T that you started with uh +uh I'm going to give you the formula for + + align:start position:0% +uh I'm going to give you the formula for + + + align:start position:0% +uh I'm going to give you the formula for +it but I first there are two ways of + + align:start position:0% +it but I first there are two ways of + + + align:start position:0% +it but I first there are two ways of +motivating it and both are important + + align:start position:0% +motivating it and both are important + + + align:start position:0% +motivating it and both are important +there's a formal motivation which is why + + align:start position:0% +there's a formal motivation which is why + + + align:start position:0% +there's a formal motivation which is why +it's tucked into this section Ono + + align:start position:0% +it's tucked into this section Ono + + + align:start position:0% +it's tucked into this section Ono +transform and the formal motivation is + + align:start position:0% +transform and the formal motivation is + + + align:start position:0% +transform and the formal motivation is +the following suppose we start with a + + align:start position:0% +the following suppose we start with a + + + align:start position:0% +the following suppose we start with a +lus transform of two different fun those + + align:start position:0% +lus transform of two different fun those + + + align:start position:0% +lus transform of two different fun those +two + + align:start position:0% +two + + + align:start position:0% +two +functions uh now the most natural + + align:start position:0% +functions uh now the most natural + + + align:start position:0% +functions uh now the most natural +question to ask is since llao transforms + + align:start position:0% +question to ask is since llao transforms + + + align:start position:0% +question to ask is since llao transforms +are really a pain to calculate is from + + align:start position:0% +are really a pain to calculate is from + + + align:start position:0% +are really a pain to calculate is from +old Lao transforms is it easy to get new + + align:start position:0% +old Lao transforms is it easy to get new + + + align:start position:0% +old Lao transforms is it easy to get new +ones and the first thing one of course + + align:start position:0% +ones and the first thing one of course + + + align:start position:0% +ones and the first thing one of course +summing functions is easy that gives you + + align:start position:0% +summing functions is easy that gives you + + + align:start position:0% +summing functions is easy that gives you +the sum of the transforms but a more + + align:start position:0% +the sum of the transforms but a more + + + align:start position:0% +the sum of the transforms but a more +natural question would be suppose I want + + align:start position:0% +natural question would be suppose I want + + + align:start position:0% +natural question would be suppose I want +to multiply F of T and G of T is there + + align:start position:0% +to multiply F of T and G of T is there + + + align:start position:0% +to multiply F of T and G of T is there +some hopefully some neat formula If I + + align:start position:0% +some hopefully some neat formula If I + + + align:start position:0% +some hopefully some neat formula If I +multiply the product of the take the + + align:start position:0% +multiply the product of the take the + + + align:start position:0% +multiply the product of the take the +product of these two is there some neat + + align:start position:0% +product of these two is there some neat + + + align:start position:0% +product of these two is there some neat +formula for the Lelo transform of that + + align:start position:0% +formula for the Lelo transform of that + + + align:start position:0% +formula for the Lelo transform of that +product that would simplify life greatly + + align:start position:0% +product that would simplify life greatly + + + align:start position:0% +product that would simplify life greatly +and the answer is there is no such + + align:start position:0% +and the answer is there is no such + + + align:start position:0% +and the answer is there is no such +formula and there never will + + align:start position:0% +formula and there never will + + + align:start position:0% +formula and there never will +be well we will not give up entirely + + align:start position:0% +be well we will not give up entirely + + + align:start position:0% +be well we will not give up entirely +suppose we ask the other + + align:start position:0% +suppose we ask the other + + + align:start position:0% +suppose we ask the other +question suppose instead I multiply the + + align:start position:0% +question suppose instead I multiply the + + + align:start position:0% +question suppose instead I multiply the +llao + + align:start position:0% +llao + + + align:start position:0% +llao +transforms could that be related to + + align:start position:0% +transforms could that be related to + + + align:start position:0% +transforms could that be related to +something I cook up out of f of T and G + + align:start position:0% +something I cook up out of f of T and G + + + align:start position:0% +something I cook up out of f of T and G +of T could it be the transform of + + align:start position:0% +of T could it be the transform of + + + align:start position:0% +of T could it be the transform of +something I cook up out of F T and G of + + align:start position:0% +something I cook up out of F T and G of + + + align:start position:0% +something I cook up out of F T and G of +T and that's what the convolution is for + + align:start position:0% +T and that's what the convolution is for + + + align:start position:0% +T and that's what the convolution is for +the answer is that F of s times G of s + + align:start position:0% +the answer is that F of s times G of s + + + align:start position:0% +the answer is that F of s times G of s +turns out to be the llao transform of + + align:start position:0% +turns out to be the llao transform of + + + align:start position:0% +turns out to be the llao transform of +the + + align:start position:0% +the + + + align:start position:0% +the +convolution the convolution and that's + + align:start position:0% +convolution the convolution and that's + + + align:start position:0% +convolution the convolution and that's +one way of defining it is the thing that + + align:start position:0% +one way of defining it is the thing that + + + align:start position:0% +one way of defining it is the thing that +you the function of T that you should + + align:start position:0% +you the function of T that you should + + + align:start position:0% +you the function of T that you should +put in there in order that its llas + + align:start position:0% +put in there in order that its llas + + + align:start position:0% +put in there in order that its llas +transform turn out to be the product of + + align:start position:0% +transform turn out to be the product of + + + align:start position:0% +transform turn out to be the product of +f of s time G of + + align:start position:0% +f of s time G of + + + align:start position:0% +f of s time G of +s + + align:start position:0% +s + + + align:start position:0% +s +now I'll give you in a moment the + + align:start position:0% +now I'll give you in a moment the + + + align:start position:0% +now I'll give you in a moment the +formula for it but I think + + align:start position:0% +formula for it but I think + + + align:start position:0% +formula for it but I think +I'll I'll give you + + align:start position:0% +I'll I'll give you + + + align:start position:0% +I'll I'll give you +one and a quarter minutes of well two + + align:start position:0% +one and a quarter minutes of well two + + + align:start position:0% +one and a quarter minutes of well two +minutes of motivation as to why there + + align:start position:0% +minutes of motivation as to why there + + + align:start position:0% +minutes of motivation as to why there +should be such a + + align:start position:0% +should be such a + + + align:start position:0% +should be such a +formula now I won't calculate this out + + align:start position:0% +formula now I won't calculate this out + + + align:start position:0% +formula now I won't calculate this out +to the end because I don't have time but + + align:start position:0% +to the end because I don't have time but + + + align:start position:0% +to the end because I don't have time but +here's the reason why there should be + + align:start position:0% +here's the reason why there should be + + + align:start position:0% +here's the reason why there should be +such a formula and you might suspect and + + align:start position:0% +such a formula and you might suspect and + + + align:start position:0% +such a formula and you might suspect and +therefore it will be worth looking for + + align:start position:0% +therefore it will be worth looking for + + + align:start position:0% +therefore it will be worth looking for +it's because remember I told you where + + align:start position:0% +it's because remember I told you where + + + align:start position:0% +it's because remember I told you where +the llast transform came from that the + + align:start position:0% +the llast transform came from that the + + + align:start position:0% +the llast transform came from that the +transform was the continuous analog of a + + align:start position:0% +transform was the continuous analog of a + + + align:start position:0% +transform was the continuous analog of a +power Series so that when you ask a + + align:start position:0% +power Series so that when you ask a + + + align:start position:0% +power Series so that when you ask a +general question like that the place to + + align:start position:0% +general question like that the place to + + + align:start position:0% +general question like that the place to +look for is if you know an analogous + + align:start position:0% +look for is if you know an analogous + + + align:start position:0% +look for is if you know an analogous +idea say does it work something like + + align:start position:0% +idea say does it work something like + + + align:start position:0% +idea say does it work something like +that work there so here I have a power + + align:start position:0% +that work there so here I have a power + + + align:start position:0% +that work there so here I have a power +series summation a n x to the N remember + + align:start position:0% +series summation a n x to the N remember + + + align:start position:0% +series summation a n x to the N remember +you can write this in computer notation + + align:start position:0% +you can write this in computer notation + + + align:start position:0% +you can write this in computer notation +as a of n to make it look like f of n f + + align:start position:0% +as a of n to make it look like f of n f + + + align:start position:0% +as a of n to make it look like f of n f +of T and the analog is between n is + + align:start position:0% +of T and the analog is between n is + + + align:start position:0% +of T and the analog is between n is +turned into T when you turn a power + + align:start position:0% +turned into T when you turn a power + + + align:start position:0% +turned into T when you turn a power +series into the plus transform and uh X + + align:start position:0% +series into the plus transform and uh X + + + align:start position:0% +series into the plus transform and uh X +gets turned into e the S and one formula + + align:start position:0% +gets turned into e the S and one formula + + + align:start position:0% +gets turned into e the S and one formula +just turns into the other okay so + + align:start position:0% +just turns into the other okay so + + + align:start position:0% +just turns into the other okay so +there's a formula for F ofx this is the + + align:start position:0% +there's a formula for F ofx this is the + + + align:start position:0% +there's a formula for F ofx this is the +analog of the llas transform and + + align:start position:0% +analog of the llas transform and + + + align:start position:0% +analog of the llas transform and +similarly G of X here is summation BN x + + align:start position:0% +similarly G of X here is summation BN x + + + align:start position:0% +similarly G of X here is summation BN x +to the + + align:start position:0% +to the + + + align:start position:0% +to the +N now again the naive question would be + + align:start position:0% +N now again the naive question would be + + + align:start position:0% +N now again the naive question would be +well suppose I multiply the two + + align:start position:0% +well suppose I multiply the two + + + align:start position:0% +well suppose I multiply the two +coefficient corresponding coefficients + + align:start position:0% +coefficient corresponding coefficients + + + align:start position:0% +coefficient corresponding coefficients +together and add up that power series + + align:start position:0% +together and add up that power series + + + align:start position:0% +together and add up that power series +summation a n b n * X the + + align:start position:0% + + + + align:start position:0% + +N is that somehow it's some related to f + + align:start position:0% +N is that somehow it's some related to f + + + align:start position:0% +N is that somehow it's some related to f +and g and of course everybody knows the + + align:start position:0% +and g and of course everybody knows the + + + align:start position:0% +and g and of course everybody knows the +answer to that is no has no relation + + align:start position:0% + + + + align:start position:0% + +whatever but suppose instead I multiply + + align:start position:0% +whatever but suppose instead I multiply + + + align:start position:0% +whatever but suppose instead I multiply +these two guys well in that case I'll + + align:start position:0% +these two guys well in that case I'll + + + align:start position:0% +these two guys well in that case I'll +get a new power + + align:start position:0% + + + + align:start position:0% + +series I don't know what its + + align:start position:0% +series I don't know what its + + + align:start position:0% +series I don't know what its +coefficients are but let's write them + + align:start position:0% +coefficients are but let's write them + + + align:start position:0% +coefficients are but let's write them +down let's just call them CN + + align:start position:0% +down let's just call them CN + + + align:start position:0% +down let's just call them CN +so what I'm asking is if this + + align:start position:0% +so what I'm asking is if this + + + align:start position:0% +so what I'm asking is if this +corresponds to the product of the two + + align:start position:0% +corresponds to the product of the two + + + align:start position:0% +corresponds to the product of the two +llast transforms and what I want to know + + align:start position:0% +llast transforms and what I want to know + + + align:start position:0% +llast transforms and what I want to know +is is there a + + align:start position:0% + + + + align:start position:0% + +formula which says that CN is equal to + + align:start position:0% +formula which says that CN is equal to + + + align:start position:0% +formula which says that CN is equal to +something that can be calcul calculated + + align:start position:0% +something that can be calcul calculated + + + align:start position:0% +something that can be calcul calculated +out of the AI and the + + align:start position:0% +out of the AI and the + + + align:start position:0% +out of the AI and the +BJ now the answer to that is yes there + + align:start position:0% +BJ now the answer to that is yes there + + + align:start position:0% +BJ now the answer to that is yes there +is and the formula for CN is called the + + align:start position:0% +is and the formula for CN is called the + + + align:start position:0% +is and the formula for CN is called the +convolution + + align:start position:0% +convolution + + + align:start position:0% +convolution +now you could figure out this formula + + align:start position:0% +now you could figure out this formula + + + align:start position:0% +now you could figure out this formula +yourself you figure it + + align:start position:0% + + + + align:start position:0% + +out anyone who's smart enough to be + + align:start position:0% +out anyone who's smart enough to be + + + align:start position:0% +out anyone who's smart enough to be +interested in the question in the first + + align:start position:0% +interested in the question in the first + + + align:start position:0% +interested in the question in the first +place is smart enough to figure out what + + align:start position:0% +place is smart enough to figure out what + + + align:start position:0% +place is smart enough to figure out what +that formula is and it will give you + + align:start position:0% +that formula is and it will give you + + + align:start position:0% +that formula is and it will give you +great pleasure to see that it's just + + align:start position:0% +great pleasure to see that it's just + + + align:start position:0% +great pleasure to see that it's just +like the formula for the convolution + + align:start position:0% +like the formula for the convolution + + + align:start position:0% +like the formula for the convolution +that I'm going to give you + + align:start position:0% +that I'm going to give you + + + align:start position:0% +that I'm going to give you +now so what is that formula for the + + align:start position:0% +now so what is that formula for the + + + align:start position:0% +now so what is that formula for the +convolution okay hang + + align:start position:0% +convolution okay hang + + + align:start position:0% +convolution okay hang +on now you're not going to lie like it + + align:start position:0% +on now you're not going to lie like it + + + align:start position:0% +on now you're not going to lie like it +but you didn't like the formula of llast + + align:start position:0% +but you didn't like the formula of llast + + + align:start position:0% +but you didn't like the formula of llast +transform either uh you felt wiser grown + + align:start position:0% +transform either uh you felt wiser grown + + + align:start position:0% +transform either uh you felt wiser grown +up getting it but it it's a mouthful to + + align:start position:0% +up getting it but it it's a mouthful to + + + align:start position:0% +up getting it but it it's a mouthful to +swallow it's something you get used to + + align:start position:0% +swallow it's something you get used to + + + align:start position:0% +swallow it's something you get used to +slowly and you'll get used to the + + align:start position:0% +slowly and you'll get used to the + + + align:start position:0% +slowly and you'll get used to the +convolution equally + + align:start position:0% +convolution equally + + + align:start position:0% +convolution equally +slowly so what is the convolution of f + + align:start position:0% +slowly so what is the convolution of f + + + align:start position:0% +slowly so what is the convolution of f +of T and G of + + align:start position:0% + + + + align:start position:0% + +T it's a function calculated according + + align:start position:0% +T it's a function calculated according + + + align:start position:0% +T it's a function calculated according +to the corresponding formula it's a + + align:start position:0% +to the corresponding formula it's a + + + align:start position:0% +to the corresponding formula it's a +function of + + align:start position:0% +function of + + + align:start position:0% +function of +T it's the integral from 0 to T + + align:start position:0% +T it's the integral from 0 to T + + + align:start position:0% +T it's the integral from 0 to T +of f of u u is a dummy variable because + + align:start position:0% +of f of u u is a dummy variable because + + + align:start position:0% +of f of u u is a dummy variable because +I'm it's going to be integrated out when + + align:start position:0% +I'm it's going to be integrated out when + + + align:start position:0% +I'm it's going to be integrated out when +I do the integration G of T minus U + + align:start position:0% + + + + align:start position:0% + +DT that's it I didn't make it up I'm + + align:start position:0% +DT that's it I didn't make it up I'm + + + align:start position:0% +DT that's it I didn't make it up I'm +just bearing the bad + + align:start position:0% + + + + align:start position:0% + +news well what do you do when you see a + + align:start position:0% +news well what do you do when you see a + + + align:start position:0% +news well what do you do when you see a +formula that seems to you know well you + + align:start position:0% +formula that seems to you know well you + + + align:start position:0% +formula that seems to you know well you +know well the first thing to do of + + align:start position:0% +know well the first thing to do of + + + align:start position:0% +know well the first thing to do of +course is try calculating just just to + + align:start position:0% +course is try calculating just just to + + + align:start position:0% +course is try calculating just just to +get some feeling for what kind of a + + align:start position:0% +get some feeling for what kind of a + + + align:start position:0% +get some feeling for what kind of a +thing you know what what's this good + + align:start position:0% +thing you know what what's this good + + + align:start position:0% +thing you know what what's this good +let's try some examples uh let's see + + align:start position:0% +let's try some examples uh let's see + + + align:start position:0% +let's try some examples uh let's see +let's calculate uh what would be a + + align:start position:0% +let's calculate uh what would be a + + + align:start position:0% +let's calculate uh what would be a +modest beginning uh let's calculate the + + align:start position:0% +modest beginning uh let's calculate the + + + align:start position:0% +modest beginning uh let's calculate the +convolution of uh t with + + align:start position:0% +convolution of uh t with + + + align:start position:0% +convolution of uh t with +itself or Betty yet let's calculate the + + align:start position:0% +itself or Betty yet let's calculate the + + + align:start position:0% +itself or Betty yet let's calculate the +convolution just so that you could tell + + align:start position:0% +convolution just so that you could tell + + + align:start position:0% +convolution just so that you could tell +the difference uh t with + + align:start position:0% +the difference uh t with + + + align:start position:0% +the difference uh t with +t2qu a t squ with t make it a little + + align:start position:0% +t2qu a t squ with t make it a little + + + align:start position:0% +t2qu a t squ with t make it a little +easier by the way the convolution is + + align:start position:0% +easier by the way the convolution is + + + align:start position:0% +easier by the way the convolution is +symmetric F star G is the same thing as + + align:start position:0% +symmetric F star G is the same thing as + + + align:start position:0% +symmetric F star G is the same thing as +G starf let's put that down explicitly I + + align:start position:0% +G starf let's put that down explicitly I + + + align:start position:0% +G starf let's put that down explicitly I +forgot to last period so tell all the + + align:start position:0% +forgot to last period so tell all the + + + align:start position:0% +forgot to last period so tell all the +guys who came to the one o'clock lecture + + align:start position:0% +guys who came to the one o'clock lecture + + + align:start position:0% +guys who came to the one o'clock lecture +did you know something that they + + align:start position:0% + + + + align:start position:0% + +don't now that's a theory it's + + align:start position:0% +don't now that's a theory it's + + + align:start position:0% +don't now that's a theory it's +commutative this operation is + + align:start position:0% +commutative this operation is + + + align:start position:0% +commutative this operation is +commutative in other words now that has + + align:start position:0% +commutative in other words now that has + + + align:start position:0% +commutative in other words now that has +to be a because the formula is not + + align:start position:0% +to be a because the formula is not + + + align:start position:0% +to be a because the formula is not +symmetric the formula does not treat f + + align:start position:0% +symmetric the formula does not treat f + + + align:start position:0% +symmetric the formula does not treat f +and g + + align:start position:0% +and g + + + align:start position:0% +and g +equally and therefore this is not + + align:start position:0% +equally and therefore this is not + + + align:start position:0% +equally and therefore this is not +obvious it's not it's at least not + + align:start position:0% +obvious it's not it's at least not + + + align:start position:0% +obvious it's not it's at least not +obvious if you look at it that way but + + align:start position:0% +obvious if you look at it that way but + + + align:start position:0% +obvious if you look at it that way but +it is obvious if you look at it that way + + align:start position:0% + + + + align:start position:0% + +why in other words F star G is the guy + + align:start position:0% +why in other words F star G is the guy + + + align:start position:0% +why in other words F star G is the guy +whose lass transform is f of s * G of + + align:start position:0% +whose lass transform is f of s * G of + + + align:start position:0% +whose lass transform is f of s * G of +s well what would G Star F be that would + + align:start position:0% +s well what would G Star F be that would + + + align:start position:0% +s well what would G Star F be that would +be the guy whose lass transform is G * F + + align:start position:0% +be the guy whose lass transform is G * F + + + align:start position:0% +be the guy whose lass transform is G * F +but F capital F time capital G is the + + align:start position:0% +but F capital F time capital G is the + + + align:start position:0% +but F capital F time capital G is the +same as capital G * capital + + align:start position:0% +same as capital G * capital + + + align:start position:0% +same as capital G * capital +F so it's because the Lao transforms are + + align:start position:0% +F so it's because the Lao transforms are + + + align:start position:0% +F so it's because the Lao transforms are +commutative ordinary multiplication is + + align:start position:0% +commutative ordinary multiplication is + + + align:start position:0% +commutative ordinary multiplication is +commutative it follows that this has to + + align:start position:0% +commutative it follows that this has to + + + align:start position:0% +commutative it follows that this has to +be comput commutative too so I'll write + + align:start position:0% +be comput commutative too so I'll write + + + align:start position:0% +be comput commutative too so I'll write +that down since f * G is equal to GF and + + align:start position:0% +that down since f * G is equal to GF and + + + align:start position:0% +that down since f * G is equal to GF and +you have to understand that here I mean + + align:start position:0% +you have to understand that here I mean + + + align:start position:0% +you have to understand that here I mean +these are the little transforms of those + + align:start position:0% +these are the little transforms of those + + + align:start position:0% +these are the little transforms of those +guys but it's not obvious from the + + align:start position:0% +guys but it's not obvious from the + + + align:start position:0% +guys but it's not obvious from the +formula okay let's calculate the LL + + align:start position:0% +formula okay let's calculate the LL + + + align:start position:0% +formula okay let's calculate the LL +transform of uh sorry the convolution of + + align:start position:0% +transform of uh sorry the convolution of + + + align:start position:0% +transform of uh sorry the convolution of +tar let's do it by the + + align:start position:0% +tar let's do it by the + + + align:start position:0% +tar let's do it by the +formula all right by the formula I + + align:start position:0% +formula all right by the formula I + + + align:start position:0% +formula all right by the formula I +calculate integral 0 to T now I take the + + align:start position:0% +calculate integral 0 to T now I take the + + + align:start position:0% +calculate integral 0 to T now I take the +first function but I change its variable + + align:start position:0% +first function but I change its variable + + + align:start position:0% +first function but I change its variable +to the dummy variable U so that's u^2 I + + align:start position:0% +to the dummy variable U so that's u^2 I + + + align:start position:0% +to the dummy variable U so that's u^2 I +take the second function and replace its + + align:start position:0% +take the second function and replace its + + + align:start position:0% +take the second function and replace its +variable by uus T so this is + + align:start position:0% +variable by uus T so this is + + + align:start position:0% +variable by uus T so this is +times U T minus U + + align:start position:0% +times U T minus U + + + align:start position:0% +times U T minus U +sorry + + align:start position:0% +sorry + + + align:start position:0% +sorry +okay do you see that this to calculate + + align:start position:0% +okay do you see that this to calculate + + + align:start position:0% +okay do you see that this to calculate +that this is what I have to write down + + align:start position:0% +that this is what I have to write down + + + align:start position:0% +that this is what I have to write down +that's what the formula + + align:start position:0% + + + + align:start position:0% + +becomes any question is it anything + + align:start position:0% + + + + align:start position:0% + +wrong oh sorry the you the integration + + align:start position:0% +wrong oh sorry the you the integration + + + align:start position:0% +wrong oh sorry the you the integration +respect to you of course this should be + + align:start position:0% +respect to you of course this should be + + + align:start position:0% +respect to you of course this should be +a thanks very + + align:start position:0% + + + + align:start position:0% + +much okay let's do it uh so it is U + + align:start position:0% +much okay let's do it uh so it is U + + + align:start position:0% +much okay let's do it uh so it is U +integral of u^2 T is remember it's + + align:start position:0% +integral of u^2 T is remember it's + + + align:start position:0% +integral of u^2 T is remember it's +integrated with respect to U so it's U + + align:start position:0% +integrated with respect to U so it's U + + + align:start position:0% +integrated with respect to U so it's U +cubed over 3 * + + align:start position:0% +cubed over 3 * + + + align:start position:0% +cubed over 3 * +T the rest of it is the integral of U + + align:start position:0% +T the rest of it is the integral of U + + + align:start position:0% +T the rest of it is the integral of U +cubed which is U 4th over 4 all this is + + align:start position:0% +cubed which is U 4th over 4 all this is + + + align:start position:0% +cubed which is U 4th over 4 all this is +to be evaluated between 0 and T at the + + align:start position:0% +to be evaluated between 0 and T at the + + + align:start position:0% +to be evaluated between 0 and T at the +upper limit so I put U equal T I get T + + align:start position:0% +upper limit so I put U equal T I get T + + + align:start position:0% +upper limit so I put U equal T I get T +4th over + + align:start position:0% +4th over + + + align:start position:0% +4th over +3 minus t 4 over four of course at the + + align:start position:0% +3 minus t 4 over four of course at the + + + align:start position:0% +3 minus t 4 over four of course at the +lower limit U is zero so both of these + + align:start position:0% +lower limit U is zero so both of these + + + align:start position:0% +lower limit U is zero so both of these +are terms are zero there's nothing there + + align:start position:0% +are terms are zero there's nothing there + + + align:start position:0% +are terms are zero there's nothing there +and the answer is therefore T 4 + + align:start position:0% +and the answer is therefore T 4 + + + align:start position:0% +and the answer is therefore T 4 +/ a 3 minus A4 is a + + align:start position:0% + + + + align:start position:0% + +12th so that's doing it from the formula + + align:start position:0% +12th so that's doing it from the formula + + + align:start position:0% +12th so that's doing it from the formula +but of course there's an easier way to + + align:start position:0% +but of course there's an easier way to + + + align:start position:0% +but of course there's an easier way to +do it uh we can I use the LL transform + + align:start position:0% +do it uh we can I use the LL transform + + + align:start position:0% +do it uh we can I use the LL transform +instead uh if I L transform it the L + + align:start position:0% +instead uh if I L transform it the L + + + align:start position:0% +instead uh if I L transform it the L +transform of t^2 is what + + align:start position:0% +transform of t^2 is what + + + align:start position:0% +transform of t^2 is what +is 2 factorial / s + + align:start position:0% +is 2 factorial / s + + + align:start position:0% +is 2 factorial / s +cubed the transform of T is 1 / + + align:start position:0% +cubed the transform of T is 1 / + + + align:start position:0% +cubed the transform of T is 1 / +S2 and so because this is the + + align:start position:0% +S2 and so because this is the + + + align:start position:0% +S2 and so because this is the +convolution of these it should + + align:start position:0% +convolution of these it should + + + align:start position:0% +convolution of these it should +correspond to the product of the Lelo + + align:start position:0% +correspond to the product of the Lelo + + + align:start position:0% +correspond to the product of the Lelo +transforms which is two over s 5th + + align:start position:0% + + + + align:start position:0% + +power well is that the same as this + + align:start position:0% +power well is that the same as this + + + align:start position:0% +power well is that the same as this +what's the L transform of in other words + + align:start position:0% +what's the L transform of in other words + + + align:start position:0% +what's the L transform of in other words +what's the inverse LL transform + + align:start position:0% +what's the inverse LL transform + + + align:start position:0% +what's the inverse LL transform +of two over S + + align:start position:0% +of two over S + + + align:start position:0% +of two over S +5 well the inverse lass transform of + + align:start position:0% +5 well the inverse lass transform of + + + align:start position:0% +5 well the inverse lass transform of +four factorial over s the 5th is how + + align:start position:0% +four factorial over s the 5th is how + + + align:start position:0% +four factorial over s the 5th is how +much that's T 4th right + + align:start position:0% + + + + align:start position:0% + +now how does this differ well to turn + + align:start position:0% +now how does this differ well to turn + + + align:start position:0% +now how does this differ well to turn +that into that I should divide by four * + + align:start position:0% +that into that I should divide by four * + + + align:start position:0% +that into that I should divide by four * +3 so this should be 112th T 4th 1 over4 + + align:start position:0% +3 so this should be 112th T 4th 1 over4 + + + align:start position:0% +3 so this should be 112th T 4th 1 over4 +* 3 because this is 24 and that's two so + + align:start position:0% +* 3 because this is 24 and that's two so + + + align:start position:0% +* 3 because this is 24 and that's two so +divide by 12 toer what constant + + align:start position:0% +divide by 12 toer what constant + + + align:start position:0% +divide by 12 toer what constant +have so it works at least in that + + align:start position:0% +have so it works at least in that + + + align:start position:0% +have so it works at least in that +case but now notice uh this is not an + + align:start position:0% +case but now notice uh this is not an + + + align:start position:0% +case but now notice uh this is not an +ordinary product the convolution of t^2 + + align:start position:0% +ordinary product the convolution of t^2 + + + align:start position:0% +ordinary product the convolution of t^2 +and T is not something like T Cub is + + align:start position:0% +and T is not something like T Cub is + + + align:start position:0% +and T is not something like T Cub is +something like T 4th power and there's a + + align:start position:0% +something like T 4th power and there's a + + + align:start position:0% +something like T 4th power and there's a +funny constant in there too very + + align:start position:0% +funny constant in there too very + + + align:start position:0% +funny constant in there too very +unpredictable let's look at the + + align:start position:0% +unpredictable let's look at the + + + align:start position:0% +unpredictable let's look at the +convolution let's take another example + + align:start position:0% +convolution let's take another example + + + align:start position:0% +convolution let's take another example +of a convolution + + align:start position:0% + + + + align:start position:0% + +uh let's do something really humble just + + align:start position:0% +uh let's do something really humble just + + + align:start position:0% +uh let's do something really humble just +to show you that this even at the + + align:start position:0% +to show you that this even at the + + + align:start position:0% +to show you that this even at the +simplest example this is not trivial + + align:start position:0% +simplest example this is not trivial + + + align:start position:0% +simplest example this is not trivial +let's take the convolution of f of t + + align:start position:0% +let's take the convolution of f of t + + + align:start position:0% +let's take the convolution of f of t +with + + align:start position:0% +with + + + align:start position:0% +with +one can you take yeah one is a function + + align:start position:0% +one can you take yeah one is a function + + + align:start position:0% +one can you take yeah one is a function +just like any function uh but you mean + + align:start position:0% +just like any function uh but you mean + + + align:start position:0% +just like any function uh but you mean +you get something out of the convolution + + align:start position:0% +you get something out of the convolution + + + align:start position:0% +you get something out of the convolution +yes + + align:start position:0% +yes + + + align:start position:0% +yes +yes let's just write down the formula + + align:start position:0% +yes let's just write down the formula + + + align:start position:0% +yes let's just write down the formula +it's now I can't use the llast transform + + align:start position:0% +it's now I can't use the llast transform + + + align:start position:0% +it's now I can't use the llast transform +here because you won't know what to do + + align:start position:0% +here because you won't know what to do + + + align:start position:0% +here because you won't know what to do +with it uh you don't have that formula + + align:start position:0% +with it uh you don't have that formula + + + align:start position:0% +with it uh you don't have that formula +yet it's a secret one that only I know + + align:start position:0% +yet it's a secret one that only I know + + + align:start position:0% +yet it's a secret one that only I know +so let's so let's do it let's use let's + + align:start position:0% +so let's so let's do it let's use let's + + + align:start position:0% +so let's so let's do it let's use let's +calculate it out the way we're supposed + + align:start position:0% +calculate it out the way we're supposed + + + align:start position:0% +calculate it out the way we're supposed +to so it's the integral from 0er to T of + + align:start position:0% +to so it's the integral from 0er to T of + + + align:start position:0% +to so it's the integral from 0er to T of +f of U and now what do I do with that + + align:start position:0% +f of U and now what do I do with that + + + align:start position:0% +f of U and now what do I do with that +one I'm supposed to take that one is the + + align:start position:0% +one I'm supposed to take that one is the + + + align:start position:0% +one I'm supposed to take that one is the +function G of T and wherever I see a t + + align:start position:0% +function G of T and wherever I see a t + + + align:start position:0% +function G of T and wherever I see a t +I'm supposed to plug in T minus U well I + + align:start position:0% +I'm supposed to plug in T minus U well I + + + align:start position:0% +I'm supposed to plug in T minus U well I +don't see any T + + align:start position:0% +don't see any T + + + align:start position:0% +don't see any T +there but that's something for rejoicing + + align:start position:0% +there but that's something for rejoicing + + + align:start position:0% +there but that's something for rejoicing +there's nothing to do to make the + + align:start position:0% +there's nothing to do to make the + + + align:start position:0% +there's nothing to do to make the +substitution it's just + + align:start position:0% + + + + align:start position:0% + +one so the answer is it's the this + + align:start position:0% +one so the answer is it's the this + + + align:start position:0% +one so the answer is it's the this +Curious Thing the convolution of a + + align:start position:0% +Curious Thing the convolution of a + + + align:start position:0% +Curious Thing the convolution of a +function with one you + + align:start position:0% +function with one you + + + align:start position:0% +function with one you +integrated from 0 to T + + align:start position:0% + + + + align:start position:0% + +well as they said now Wonderland was it + + align:start position:0% +well as they said now Wonderland was it + + + align:start position:0% +well as they said now Wonderland was it +things are getting curiouser and + + align:start position:0% +things are getting curiouser and + + + align:start position:0% +things are getting curiouser and +curiouser uh I mean what is going on + + align:start position:0% +curiouser uh I mean what is going on + + + align:start position:0% +curiouser uh I mean what is going on +with this crazy function and where are + + align:start position:0% +with this crazy function and where are + + + align:start position:0% +with this crazy function and where are +we supposed to start with it well I'm + + align:start position:0% +we supposed to start with it well I'm + + + align:start position:0% +we supposed to start with it well I'm +going to prove this for you uh mostly + + align:start position:0% +going to prove this for you uh mostly + + + align:start position:0% +going to prove this for you uh mostly +because the proof is easy in other words + + align:start position:0% +because the proof is easy in other words + + + align:start position:0% +because the proof is easy in other words +I'm going to prove prove that that's + + align:start position:0% +I'm going to prove prove that that's + + + align:start position:0% +I'm going to prove prove that that's +true and + + align:start position:0% +true and + + + align:start position:0% +true and +as I give the proof you'll see where the + + align:start position:0% +as I give the proof you'll see where the + + + align:start position:0% +as I give the proof you'll see where the +convolution is coming from that's number + + align:start position:0% +convolution is coming from that's number + + + align:start position:0% +convolution is coming from that's number +one and number two the real reason I'm + + align:start position:0% +one and number two the real reason I'm + + + align:start position:0% +one and number two the real reason I'm +giving you the proof because it's a + + align:start position:0% +giving you the proof because it's a + + + align:start position:0% +giving you the proof because it's a +marvelous it's a marvelous exercise in + + align:start position:0% +marvelous it's a marvelous exercise in + + + align:start position:0% +marvelous it's a marvelous exercise in +changing the variables in a double + + align:start position:0% +changing the variables in a double + + + align:start position:0% +changing the variables in a double +integral now that's something you all + + align:start position:0% +integral now that's something you all + + + align:start position:0% +integral now that's something you all +know how to do even the ones who are + + align:start position:0% +know how to do even the ones who are + + + align:start position:0% +know how to do even the ones who are +taking 1802 concurrently and I didn't + + align:start position:0% +taking 1802 concurrently and I didn't + + + align:start position:0% +taking 1802 concurrently and I didn't +advise you to do that uh but I've + + align:start position:0% +advise you to do that uh but I've + + + align:start position:0% +advise you to do that uh but I've +arranged the course so it's possible to + + align:start position:0% +arranged the course so it's possible to + + + align:start position:0% +arranged the course so it's possible to +do but I knew that by the time we got to + + align:start position:0% +do but I knew that by the time we got to + + + align:start position:0% +do but I knew that by the time we got to +this you would already know how to + + align:start position:0% +this you would already know how to + + + align:start position:0% +this you would already know how to +change variables at a double integral so + + align:start position:0% +change variables at a double integral so + + + align:start position:0% +change variables at a double integral so +and in fact you'll have the advantage of + + align:start position:0% +and in fact you'll have the advantage of + + + align:start position:0% +and in fact you'll have the advantage of +remembering how to do it because you + + align:start position:0% +remembering how to do it because you + + + align:start position:0% +remembering how to do it because you +just had it a week or two ago whereas + + align:start position:0% +just had it a week or two ago whereas + + + align:start position:0% +just had it a week or two ago whereas +all the other guys is something dim in + + align:start position:0% +all the other guys is something dim in + + + align:start position:0% +all the other guys is something dim in +their distance and so I'm reviewing how + + align:start position:0% +their distance and so I'm reviewing how + + + align:start position:0% +their distance and so I'm reviewing how +to change variables at a double + + align:start position:0% +to change variables at a double + + + align:start position:0% +to change variables at a double +integral I'm showing you it's good for + + align:start position:0% + + + + align:start position:0% + +something so what we're out to try to + + align:start position:0% +something so what we're out to try to + + + align:start position:0% +something so what we're out to try to +prove is this + + align:start position:0% +prove is this + + + align:start position:0% +prove is this +formula + + align:start position:0% +formula + + + align:start position:0% +formula +let's put that down in so you + + align:start position:0% + + + + align:start position:0% + +understand okay let's do + + align:start position:0% +understand okay let's do + + + align:start position:0% +understand okay let's do +it now we'll use the desert island + + align:start position:0% +it now we'll use the desert island + + + align:start position:0% +it now we'll use the desert island +method so you have as much time as you + + align:start position:0% +method so you have as much time as you + + + align:start position:0% +method so you have as much time as you +want your desert island I in fact I'm + + align:start position:0% +want your desert island I in fact I'm + + + align:start position:0% +want your desert island I in fact I'm +going to even go it the opposite + + align:start position:0% +going to even go it the opposite + + + align:start position:0% +going to even go it the opposite +way I'm going to start with you got a + + align:start position:0% +way I'm going to start with you got a + + + align:start position:0% +way I'm going to start with you got a +lot of time on your hand say gee I + + align:start position:0% +lot of time on your hand say gee I + + + align:start position:0% +lot of time on your hand say gee I +wonder if there's a + + align:start position:0% +wonder if there's a + + + align:start position:0% +wonder if there's a +if I take the product of the llast + + align:start position:0% +if I take the product of the llast + + + align:start position:0% +if I take the product of the llast +transforms I wonder if there's some + + align:start position:0% +transforms I wonder if there's some + + + align:start position:0% +transforms I wonder if there's some +crazy function I could put in there + + align:start position:0% +crazy function I could put in there + + + align:start position:0% +crazy function I could put in there +which would make things work you've + + align:start position:0% +which would make things work you've + + + align:start position:0% +which would make things work you've +never heard of the convolution you're + + align:start position:0% +never heard of the convolution you're + + + align:start position:0% +never heard of the convolution you're +going to discover it all by + + align:start position:0% +going to discover it all by + + + align:start position:0% +going to discover it all by +yourself okay so how do you begin so + + align:start position:0% +yourself okay so how do you begin so + + + align:start position:0% +yourself okay so how do you begin so +we'll start with the left hand side + + align:start position:0% +we'll start with the left hand side + + + align:start position:0% +we'll start with the left hand side +we'll looking + + align:start position:0% +we'll looking + + + align:start position:0% +we'll looking +for some nice way of calculating that as + + align:start position:0% +for some nice way of calculating that as + + + align:start position:0% +for some nice way of calculating that as +the llao transform of a single function + + align:start position:0% +the llao transform of a single function + + + align:start position:0% +the llao transform of a single function +so the way to begin is by writing out + + align:start position:0% +so the way to begin is by writing out + + + align:start position:0% +so the way to begin is by writing out +the definitions we couldn't use anything + + align:start position:0% +the definitions we couldn't use anything + + + align:start position:0% +the definitions we couldn't use anything +else since we don't have anything else + + align:start position:0% +else since we don't have anything else + + + align:start position:0% +else since we don't have anything else +to use now looking ahead I'm going to + + align:start position:0% +to use now looking ahead I'm going to + + + align:start position:0% +to use now looking ahead I'm going to +not use T I'm going to use two neutral + + align:start position:0% +not use T I'm going to use two neutral + + + align:start position:0% +not use T I'm going to use two neutral +variables when I calculate after all the + + align:start position:0% +variables when I calculate after all the + + + align:start position:0% +variables when I calculate after all the +t is just a dummy variable anyway you'll + + align:start position:0% +t is just a dummy variable anyway you'll + + + align:start position:0% +t is just a dummy variable anyway you'll +see uh in a minute the wisdom of doing + + align:start position:0% +see uh in a minute the wisdom of doing + + + align:start position:0% +see uh in a minute the wisdom of doing +this so it's this times the integral + + align:start position:0% +this so it's this times the integral + + + align:start position:0% +this so it's this times the integral +which gives the lass transform of G so + + align:start position:0% +which gives the lass transform of G so + + + align:start position:0% +which gives the lass transform of G so +that's e to the S V let's say times G of + + align:start position:0% +that's e to the S V let's say times G of + + + align:start position:0% +that's e to the S V let's say times G of +V + + align:start position:0% +V + + + align:start position:0% +V +DV okay everybody can get that far and + + align:start position:0% +DV okay everybody can get that far and + + + align:start position:0% +DV okay everybody can get that far and +now we have to start looking + + align:start position:0% +now we have to start looking + + + align:start position:0% +now we have to start looking +well this is a single integral an 1801 + + align:start position:0% +well this is a single integral an 1801 + + + align:start position:0% +well this is a single integral an 1801 +integral involving U and this is an 1801 + + align:start position:0% +integral involving U and this is an 1801 + + + align:start position:0% +integral involving U and this is an 1801 +integral involving V but when you take + + align:start position:0% +integral involving V but when you take + + + align:start position:0% +integral involving V but when you take +the product of two integrals like that + + align:start position:0% +the product of two integrals like that + + + align:start position:0% +the product of two integrals like that +remember when you evaluate a double + + align:start position:0% +remember when you evaluate a double + + + align:start position:0% +remember when you evaluate a double +integral there's an easy case where you + + align:start position:0% +integral there's an easy case where you + + + align:start position:0% +integral there's an easy case where you +don't it's much easier than any other + + align:start position:0% +don't it's much easier than any other + + + align:start position:0% +don't it's much easier than any other +case if you could write the inside if + + align:start position:0% +case if you could write the inside if + + + align:start position:0% +case if you could write the inside if +you're integrating over a rectangle for + + align:start position:0% +you're integrating over a rectangle for + + + align:start position:0% +you're integrating over a rectangle for +example and and you can write the + + align:start position:0% +example and and you can write the + + + align:start position:0% +example and and you can write the +integral as product of a function just + + align:start position:0% +integral as product of a function just + + + align:start position:0% +integral as product of a function just +of U and the product of a function just + + align:start position:0% +of U and the product of a function just + + + align:start position:0% +of U and the product of a function just +is V then the integral is very easy to + + align:start position:0% +is V then the integral is very easy to + + + align:start position:0% +is V then the integral is very easy to +evaluate you can forget all the rules + + align:start position:0% +evaluate you can forget all the rules + + + align:start position:0% +evaluate you can forget all the rules +you just take all the U part out all the + + align:start position:0% +you just take all the U part out all the + + + align:start position:0% +you just take all the U part out all the +V part out and integrate them separately + + align:start position:0% +V part out and integrate them separately + + + align:start position:0% +V part out and integrate them separately +A to B C to d That's the easy case of + + align:start position:0% +A to B C to d That's the easy case of + + + align:start position:0% +A to B C to d That's the easy case of +evaluating a double integral it's what + + align:start position:0% +evaluating a double integral it's what + + + align:start position:0% +evaluating a double integral it's what +everybody tries to do even when it's not + + align:start position:0% +everybody tries to do even when it's not + + + align:start position:0% +everybody tries to do even when it's not +appropriate now here it is appropriate + + align:start position:0% +appropriate now here it is appropriate + + + align:start position:0% +appropriate now here it is appropriate +except I'm going to use it backwards + + align:start position:0% +except I'm going to use it backwards + + + align:start position:0% +except I'm going to use it backwards +this is the result of having done that + + align:start position:0% +this is the result of having done that + + + align:start position:0% +this is the result of having done that +if this is the result of having done it + + align:start position:0% +if this is the result of having done it + + + align:start position:0% +if this is the result of having done it +what was the step just before it well I + + align:start position:0% +what was the step just before it well I + + + align:start position:0% +what was the step just before it well I +must have been trying to evaluate a + + align:start position:0% +must have been trying to evaluate a + + + align:start position:0% +must have been trying to evaluate a +double + + align:start position:0% +double + + + align:start position:0% +double +integral as U runs from zero to infinity + + align:start position:0% +integral as U runs from zero to infinity + + + align:start position:0% +integral as U runs from zero to infinity +and V runs from zero to Infinity of what + + align:start position:0% +and V runs from zero to Infinity of what + + + align:start position:0% +and V runs from zero to Infinity of what +well of the product of these two + + align:start position:0% +well of the product of these two + + + align:start position:0% +well of the product of these two +functions now what is that e Theus Su * + + align:start position:0% +functions now what is that e Theus Su * + + + align:start position:0% +functions now what is that e Theus Su * +e Theus SV well I must surely want to + + align:start position:0% +e Theus SV well I must surely want to + + + align:start position:0% +e Theus SV well I must surely want to +combine + + align:start position:0% +combine + + + align:start position:0% +combine +those eus Su * eus s B and what's left + + align:start position:0% +those eus Su * eus s B and what's left + + + align:start position:0% +those eus Su * eus s B and what's left +well what's gets dragged along + + align:start position:0% +well what's gets dragged along + + + align:start position:0% +well what's gets dragged along +DV this is the same as that because of + + align:start position:0% +DV this is the same as that because of + + + align:start position:0% +DV this is the same as that because of +that law I just gave you this is the + + align:start position:0% +that law I just gave you this is the + + + align:start position:0% +that law I just gave you this is the +product of a function just of U and a + + align:start position:0% +product of a function just of U and a + + + align:start position:0% +product of a function just of U and a +function just of v and therefore it's + + align:start position:0% +function just of v and therefore it's + + + align:start position:0% +function just of v and therefore it's +okay to separate the two integrals out + + align:start position:0% +okay to separate the two integrals out + + + align:start position:0% +okay to separate the two integrals out +that way because I'm integrating a sort + + align:start position:0% +that way because I'm integrating a sort + + + align:start position:0% +that way because I'm integrating a sort +of a rectangle it goes to Infinity that + + align:start position:0% +of a rectangle it goes to Infinity that + + + align:start position:0% +of a rectangle it goes to Infinity that +way and infinity that way but what I'm + + align:start position:0% +way and infinity that way but what I'm + + + align:start position:0% +way and infinity that way but what I'm +integrating is over the plane in other + + align:start position:0% +integrating is over the plane in other + + + align:start position:0% +integrating is over the plane in other +words this region of the plane + + align:start position:0% +words this region of the plane + + + align:start position:0% +words this region of the plane +as u v goes from zero to Infinity zero + + align:start position:0% +as u v goes from zero to Infinity zero + + + align:start position:0% +as u v goes from zero to Infinity zero +to + + align:start position:0% + + + + align:start position:0% + +Infinity + + align:start position:0% +Infinity + + + align:start position:0% +Infinity +now let's take a look what are we + + align:start position:0% +now let's take a look what are we + + + align:start position:0% +now let's take a look what are we +looking for well we're looking for we + + align:start position:0% +looking for well we're looking for we + + + align:start position:0% +looking for well we're looking for we +would be very happy if U plus v were + + align:start position:0% + + + + align:start position:0% + +T let's make it + + align:start position:0% + + + + align:start position:0% + +t in other words I'm introducing a new + + align:start position:0% +t in other words I'm introducing a new + + + align:start position:0% +t in other words I'm introducing a new +variable t u plus v and it's suggested + + align:start position:0% +variable t u plus v and it's suggested + + + align:start position:0% +variable t u plus v and it's suggested +by the form in which I'm looking for the + + align:start position:0% +by the form in which I'm looking for the + + + align:start position:0% +by the form in which I'm looking for the +answer now you of course you then have + + align:start position:0% +answer now you of course you then have + + + align:start position:0% +answer now you of course you then have +to we need another variable we could + + align:start position:0% +to we need another variable we could + + + align:start position:0% +to we need another variable we could +keep either U or V oh let's keep U that + + align:start position:0% +keep either U or V oh let's keep U that + + + align:start position:0% +keep either U or V oh let's keep U that +means V we this game of musical chairs V + + align:start position:0% +means V we this game of musical chairs V + + + align:start position:0% +means V we this game of musical chairs V +got dropped out uh well we can't have + + align:start position:0% +got dropped out uh well we can't have + + + align:start position:0% +got dropped out uh well we can't have +three variables we only have room for + + align:start position:0% +three variables we only have room for + + + align:start position:0% +three variables we only have room for +two but uh we will remember + + align:start position:0% +two but uh we will remember + + + align:start position:0% +two but uh we will remember +it rest in peace V was equal to T minus + + align:start position:0% +it rest in peace V was equal to T minus + + + align:start position:0% +it rest in peace V was equal to T minus +U in we ever need him + + align:start position:0% + + + + align:start position:0% + +again okay let's now put in the limits + + align:start position:0% +again okay let's now put in the limits + + + align:start position:0% +again okay let's now put in the limits +let's put in the integral the rest of + + align:start position:0% +let's put in the integral the rest of + + + align:start position:0% +let's put in the integral the rest of +the change of variable so it's e so I'm + + align:start position:0% +the change of variable so it's e so I'm + + + align:start position:0% +the change of variable so it's e so I'm +now changing it to these new variables T + + align:start position:0% +now changing it to these new variables T + + + align:start position:0% +now changing it to these new variables T +and U so it's e to the negative St well + + align:start position:0% +and U so it's e to the negative St well + + + align:start position:0% +and U so it's e to the negative St well +F of U I don't have to do anything + + align:start position:0% +F of U I don't have to do anything + + + align:start position:0% +F of U I don't have to do anything +to but G of V I'm not allowed to keep V + + align:start position:0% +to but G of V I'm not allowed to keep V + + + align:start position:0% +to but G of V I'm not allowed to keep V +so V has to be changed to T minus U + + align:start position:0% + + + + align:start position:0% + +amazing things are + + align:start position:0% +amazing things are + + + align:start position:0% +amazing things are +happening + + align:start position:0% +happening + + + align:start position:0% +happening +du now I want to change this to an + + align:start position:0% +du now I want to change this to an + + + align:start position:0% +du now I want to change this to an +integral du DT now for that you have to + + align:start position:0% +integral du DT now for that you have to + + + align:start position:0% +integral du DT now for that you have to +be a little careful we have two things + + align:start position:0% +be a little careful we have two things + + + align:start position:0% +be a little careful we have two things +to do to figure out this what goes with + + align:start position:0% +to do to figure out this what goes with + + + align:start position:0% +to do to figure out this what goes with +that and we have to put in the limits + + align:start position:0% +that and we have to put in the limits + + + align:start position:0% +that and we have to put in the limits +also now those are the two non-trivial + + align:start position:0% +also now those are the two non-trivial + + + align:start position:0% +also now those are the two non-trivial +operations when you change integrals in + + align:start position:0% +operations when you change integrals in + + + align:start position:0% +operations when you change integrals in +a change variables in a double integral + + align:start position:0% +a change variables in a double integral + + + align:start position:0% +a change variables in a double integral +so let's be really careful let's do the + + align:start position:0% +so let's be really careful let's do the + + + align:start position:0% +so let's be really careful let's do the +easier of the two first I want to change + + align:start position:0% +easier of the two first I want to change + + + align:start position:0% +easier of the two first I want to change +from du DV + + align:start position:0% +from du DV + + + align:start position:0% +from du DV +to duu DT and now to do that you have to + + align:start position:0% +to duu DT and now to do that you have to + + + align:start position:0% +to duu DT and now to do that you have to +put in the Jacobian matrix the Jacobian + + align:start position:0% +put in the Jacobian matrix the Jacobian + + + align:start position:0% +put in the Jacobian matrix the Jacobian +DET ter + + align:start position:0% +DET ter + + + align:start position:0% +DET ter +ah you how many of you forgot that I + + align:start position:0% +ah you how many of you forgot that I + + + align:start position:0% +ah you how many of you forgot that I +won't even bother asking + + align:start position:0% + + + + align:start position:0% + +uh oh come on you only lose two points + + align:start position:0% +uh oh come on you only lose two points + + + align:start position:0% +uh oh come on you only lose two points +what's the it doesn't matter if you put + + align:start position:0% +what's the it doesn't matter if you put + + + align:start position:0% +what's the it doesn't matter if you put +in the Jacobian uh as you see you know + + align:start position:0% +in the Jacobian uh as you see you know + + + align:start position:0% +in the Jacobian uh as you see you know +going forget something you'll lose less + + align:start position:0% +going forget something you'll lose less + + + align:start position:0% +going forget something you'll lose less +credit for forgetting that than anything + + align:start position:0% +credit for forgetting that than anything + + + align:start position:0% +credit for forgetting that than anything +else so it's the Jacobian of u and v + + align:start position:0% +else so it's the Jacobian of u and v + + + align:start position:0% +else so it's the Jacobian of u and v +with respect to U and T So to calculate + + align:start position:0% +with respect to U and T So to calculate + + + align:start position:0% +with respect to U and T So to calculate +that you write U equals u v equals uh T + + align:start position:0% +that you write U equals u v equals uh T + + + align:start position:0% +that you write U equals u v equals uh T +minus + + align:start position:0% +minus + + + align:start position:0% +minus +U and then the Jacobian + + align:start position:0% + + + + align:start position:0% + +is the Jacobian is uh blah blah blah + + align:start position:0% +is the Jacobian is uh blah blah blah + + + align:start position:0% +is the Jacobian is uh blah blah blah +blah blah blah + + align:start position:0% +blah blah blah + + + align:start position:0% +blah blah blah +uh the partial The Matrix of the + + align:start position:0% +uh the partial The Matrix of the + + + align:start position:0% +uh the partial The Matrix of the +determinant of partial + + align:start position:0% + + + + align:start position:0% + +derivatives so it's the determinant + + align:start position:0% +derivatives so it's the determinant + + + align:start position:0% +derivatives so it's the determinant +whose entries are the partial of U with + + align:start position:0% +whose entries are the partial of U with + + + align:start position:0% +whose entries are the partial of U with +respect to U the partial of U with + + align:start position:0% +respect to U the partial of U with + + + align:start position:0% +respect to U the partial of U with +respect to T but these are independent + + align:start position:0% +respect to T but these are independent + + + align:start position:0% +respect to T but these are independent +variables so that's zero the partial of + + align:start position:0% +variables so that's zero the partial of + + + align:start position:0% +variables so that's zero the partial of +V with respect to U is negative one the + + align:start position:0% +V with respect to U is negative one the + + + align:start position:0% +V with respect to U is negative one the +partial of V with respect to T is one so + + align:start position:0% +partial of V with respect to T is one so + + + align:start position:0% +partial of V with respect to T is one so +the Jacobian is one so if you forgot it + + align:start position:0% +the Jacobian is one so if you forgot it + + + align:start position:0% +the Jacobian is one so if you forgot it +no + + align:start position:0% +no + + + align:start position:0% +no +harm + + align:start position:0% + + + + align:start position:0% + +so the Jacobian is + + align:start position:0% +so the Jacobian is + + + align:start position:0% +so the Jacobian is +one now more serious and in some ways I + + align:start position:0% +one now more serious and in some ways I + + + align:start position:0% +one now more serious and in some ways I +think for most of you the most difficult + + align:start position:0% +think for most of you the most difficult + + + align:start position:0% +think for most of you the most difficult +part of the operation is putting in the + + align:start position:0% +part of the operation is putting in the + + + align:start position:0% +part of the operation is putting in the +new + + align:start position:0% +new + + + align:start position:0% +new +livits now for that you look at the + + align:start position:0% +livits now for that you look at the + + + align:start position:0% +livits now for that you look at the +region over which you're integrating I + + align:start position:0% +region over which you're integrating I + + + align:start position:0% +region over which you're integrating I +think I better do that carefully uh + + align:start position:0% +think I better do that carefully uh + + + align:start position:0% +think I better do that carefully uh +let's I need a bigger picture that's + + align:start position:0% +let's I need a bigger picture that's + + + align:start position:0% +let's I need a bigger picture that's +really what I'm trying to say so here is + + align:start position:0% +really what I'm trying to say so here is + + + align:start position:0% +really what I'm trying to say so here is +the UV coordinates and I want to change + + align:start position:0% +the UV coordinates and I want to change + + + align:start position:0% +the UV coordinates and I want to change +these to UV to UT coordinates the + + align:start position:0% +these to UV to UT coordinates the + + + align:start position:0% +these to UV to UT coordinates the +integration is over the first + + align:start position:0% +integration is over the first + + + align:start position:0% +integration is over the first +quadrant so what you do is when you do + + align:start position:0% +quadrant so what you do is when you do + + + align:start position:0% +quadrant so what you do is when you do +the integral the first step is U is + + align:start position:0% +the integral the first step is U is + + + align:start position:0% +the integral the first step is U is +varying and T is held fixed so in the + + align:start position:0% +varying and T is held fixed so in the + + + align:start position:0% +varying and T is held fixed so in the +first integration U + + align:start position:0% + + + + align:start position:0% + +varies T is held fixed now what is + + align:start position:0% +varies T is held fixed now what is + + + align:start position:0% +varies T is held fixed now what is +holding T fixed in this picture mean + + align:start position:0% +holding T fixed in this picture mean + + + align:start position:0% +holding T fixed in this picture mean +well T is equal to U + V so U plus v is + + align:start position:0% +well T is equal to U + V so U plus v is + + + align:start position:0% +well T is equal to U + V so U plus v is +fixed is a constant in other words now + + align:start position:0% +fixed is a constant in other words now + + + align:start position:0% +fixed is a constant in other words now +where are the curves along which U plus + + align:start position:0% +where are the curves along which U plus + + + align:start position:0% +where are the curves along which U plus +v is a constant well they are these + + align:start position:0% + + + + align:start position:0% + +lines these are the lines along which u+ + + align:start position:0% +lines these are the lines along which u+ + + + align:start position:0% +lines these are the lines along which u+ +V equals a constant or t is a constant + + align:start position:0% +V equals a constant or t is a constant + + + align:start position:0% +V equals a constant or t is a constant +the reason I'm holding t a constant is + + align:start position:0% +the reason I'm holding t a constant is + + + align:start position:0% +the reason I'm holding t a constant is +because the first integration only + + align:start position:0% +because the first integration only + + + align:start position:0% +because the first integration only +allows U to change T is held + + align:start position:0% + + + + align:start position:0% + +fixed okay you let U + + align:start position:0% +fixed okay you let U + + + align:start position:0% +fixed okay you let U +increase as U increase and T is held + + align:start position:0% +increase as U increase and T is held + + + align:start position:0% +increase as U increase and T is held +fixed I'm traversing these lines in this + + align:start position:0% +fixed I'm traversing these lines in this + + + align:start position:0% +fixed I'm traversing these lines in this +Direction that's the direction on which + + align:start position:0% +Direction that's the direction on which + + + align:start position:0% +Direction that's the direction on which +U is increasing I integrate from the + + align:start position:0% +U is increasing I integrate from the + + + align:start position:0% +U is increasing I integrate from the +point from the U value where they leave + + align:start position:0% +point from the U value where they leave + + + align:start position:0% +point from the U value where they leave +the region into enter the region what's + + align:start position:0% +the region into enter the region what's + + + align:start position:0% +the region into enter the region what's +the U value where they enter the region + + align:start position:0% +the U value where they enter the region + + + align:start position:0% +the U value where they enter the region +U is equal to zero everybody would know + + align:start position:0% +U is equal to zero everybody would know + + + align:start position:0% +U is equal to zero everybody would know +that not so many people would be able to + + align:start position:0% +that not so many people would be able to + + + align:start position:0% +that not so many people would be able to +figure out what to put for where it + + align:start position:0% +figure out what to put for where it + + + align:start position:0% +figure out what to put for where it +leaves the + + align:start position:0% +leaves the + + + align:start position:0% +leaves the +region what's U the value of U when it + + align:start position:0% +region what's U the value of U when it + + + align:start position:0% +region what's U the value of U when it +leaves the region well this is the curve + + align:start position:0% +leaves the region well this is the curve + + + align:start position:0% +leaves the region well this is the curve +v equals 0 but V equals 0 is in another + + align:start position:0% +v equals 0 but V equals 0 is in another + + + align:start position:0% +v equals 0 but V equals 0 is in another +language U equals T T minus U equal 0 or + + align:start position:0% +language U equals T T minus U equal 0 or + + + align:start position:0% +language U equals T T minus U equal 0 or +U equals T in other words they enter the + + align:start position:0% +U equals T in other words they enter the + + + align:start position:0% +U equals T in other words they enter the +region where U equals 0 and they leave + + align:start position:0% +region where U equals 0 and they leave + + + align:start position:0% +region where U equals 0 and they leave +where U is T has the value + + align:start position:0% + + + + align:start position:0% + +t + + align:start position:0% + + + + align:start position:0% + +and how about the other guys for which + + align:start position:0% +and how about the other guys for which + + + align:start position:0% +and how about the other guys for which +T's do I want to do this well I want to + + align:start position:0% +T's do I want to do this well I want to + + + align:start position:0% +T's do I want to do this well I want to +do it for all these T values well now + + align:start position:0% +do it for all these T values well now + + + align:start position:0% +do it for all these T values well now +the T value here that's the starting one + + align:start position:0% +the T value here that's the starting one + + + align:start position:0% +the T value here that's the starting one +here T is zero and here T is not zero + + align:start position:0% +here T is zero and here T is not zero + + + align:start position:0% +here T is zero and here T is not zero +and if I go out and cover the whole + + align:start position:0% +and if I go out and cover the whole + + + align:start position:0% +and if I go out and cover the whole +first quadrant I'll be going letting T + + align:start position:0% +first quadrant I'll be going letting T + + + align:start position:0% +first quadrant I'll be going letting T +increase to Infinity the sum of u and v + + align:start position:0% +increase to Infinity the sum of u and v + + + align:start position:0% +increase to Infinity the sum of u and v +i will be letting increase to Infinity + + align:start position:0% +i will be letting increase to Infinity + + + align:start position:0% +i will be letting increase to Infinity +so it's 0 to Infinity so all this is an + + align:start position:0% +so it's 0 to Infinity so all this is an + + + align:start position:0% +so it's 0 to Infinity so all this is an +exercise in changing taking this double + + align:start position:0% +exercise in changing taking this double + + + align:start position:0% +exercise in changing taking this double +integral in UV coordinates and changing + + align:start position:0% +integral in UV coordinates and changing + + + align:start position:0% +integral in UV coordinates and changing +it to this double integral an equivalent + + align:start position:0% +it to this double integral an equivalent + + + align:start position:0% +it to this double integral an equivalent +double integral over the same region but + + align:start position:0% +double integral over the same region but + + + align:start position:0% +double integral over the same region but +now in ut coordinates and now that's the + + align:start position:0% +now in ut coordinates and now that's the + + + align:start position:0% +now in ut coordinates and now that's the +answer somewhere here is the answer + + align:start position:0% +answer somewhere here is the answer + + + align:start position:0% +answer somewhere here is the answer +because + + align:start position:0% +because + + + align:start position:0% +because +look because look if I + + align:start position:0% +look because look if I + + + align:start position:0% +look because look if I +uh since the first integration is with + + align:start position:0% +uh since the first integration is with + + + align:start position:0% +uh since the first integration is with +respect to you this this guy can migrate + + align:start position:0% +respect to you this this guy can migrate + + + align:start position:0% +respect to you this this guy can migrate +outside because it doesn't involve + + align:start position:0% +outside because it doesn't involve + + + align:start position:0% +outside because it doesn't involve +you that only involves T and T is only + + align:start position:0% +you that only involves T and T is only + + + align:start position:0% +you that only involves T and T is only +caught by the second integration so I + + align:start position:0% +caught by the second integration so I + + + align:start position:0% +caught by the second integration so I +can put this outside and what do I end + + align:start position:0% +can put this outside and what do I end + + + align:start position:0% +can put this outside and what do I end +up with the integral from zero to + + align:start position:0% +up with the integral from zero to + + + align:start position:0% +up with the integral from zero to +Infinity of e to the negative St times + + align:start position:0% +Infinity of e to the negative St times + + + align:start position:0% +Infinity of e to the negative St times +what's left a funny expression but + + align:start position:0% +what's left a funny expression but + + + align:start position:0% +what's left a funny expression but +you're on your desert island and found + + align:start position:0% +you're on your desert island and found + + + align:start position:0% +you're on your desert island and found +it this funny expression integral from 0 + + align:start position:0% +it this funny expression integral from 0 + + + align:start position:0% +it this funny expression integral from 0 +to T F of uu G of T minus U du in short + + align:start position:0% +to T F of uu G of T minus U du in short + + + align:start position:0% +to T F of uu G of T minus U du in short +the convolution exactly the + + align:start position:0% + + + + align:start position:0% + +convolution so all you have to do is get + + align:start position:0% +convolution so all you have to do is get + + + align:start position:0% +convolution so all you have to do is get +the idea that there might be a formula + + align:start position:0% +the idea that there might be a formula + + + align:start position:0% +the idea that there might be a formula +sit down change variables the double + + align:start position:0% +sit down change variables the double + + + align:start position:0% +sit down change variables the double +integral Echo you got your formula + + align:start position:0% + + + + align:start position:0% + +well I would like to spend much of the + + align:start position:0% +well I would like to spend much of the + + + align:start position:0% +well I would like to spend much of the +rest of the + + align:start position:0% +rest of the + + + align:start position:0% +rest of the +period + + align:start position:0% +period + + + align:start position:0% +period +in other words so that's how it relates + + align:start position:0% +in other words so that's how it relates + + + align:start position:0% +in other words so that's how it relates +to the luse transform that's how it + + align:start position:0% +to the luse transform that's how it + + + align:start position:0% +to the luse transform that's how it +comes out of the LL transform here's how + + align:start position:0% +comes out of the LL transform here's how + + + align:start position:0% +comes out of the LL transform here's how +to use it you know calculate it either + + align:start position:0% +to use it you know calculate it either + + + align:start position:0% +to use it you know calculate it either +with a llao transform or directly from + + align:start position:0% +with a llao transform or directly from + + + align:start position:0% +with a llao transform or directly from +the integral and of course you'll solve + + align:start position:0% +the integral and of course you'll solve + + + align:start position:0% +the integral and of course you'll solve +problems llao transform problems + + align:start position:0% +problems llao transform problems + + + align:start position:0% +problems llao transform problems +differential equations using the + + align:start position:0% +differential equations using the + + + align:start position:0% +differential equations using the +convolution but I have to tell you that + + align:start position:0% +convolution but I have to tell you that + + + align:start position:0% +convolution but I have to tell you that +most people convolution is very + + align:start position:0% +most people convolution is very + + + align:start position:0% +most people convolution is very +important and most people who use it + + align:start position:0% +important and most people who use it + + + align:start position:0% +important and most people who use it +don't use it in connection of the llao + + align:start position:0% +don't use it in connection of the llao + + + align:start position:0% +don't use it in connection of the llao +transform they use it for its own + + align:start position:0% +transform they use it for its own + + + align:start position:0% +transform they use it for its own +sake uh the first + + align:start position:0% +sake uh the first + + + align:start position:0% +sake uh the first +place I learned that you know outside of + + align:start position:0% +place I learned that you know outside of + + + align:start position:0% +place I learned that you know outside of +MIT people use the convolution was + + align:start position:0% +MIT people use the convolution was + + + align:start position:0% +MIT people use the convolution was +actually from my daughter who uh you + + align:start position:0% +actually from my daughter who uh you + + + align:start position:0% +actually from my daughter who uh you +know is she's an environmental engineer + + align:start position:0% +know is she's an environmental engineer + + + align:start position:0% +know is she's an environmental engineer +a consultant uh environmental consultant + + align:start position:0% +a consultant uh environmental consultant + + + align:start position:0% +a consultant uh environmental consultant +she does risk assessment stuff like that + + align:start position:0% +she does risk assessment stuff like that + + + align:start position:0% +she does risk assessment stuff like that +but anyway she had this paper on acid + + align:start position:0% +but anyway she had this paper on acid + + + align:start position:0% +but anyway she had this paper on acid +range she was trying to read for a + + align:start position:0% +range she was trying to read for a + + + align:start position:0% +range she was trying to read for a +client and uh she said you know was + + align:start position:0% +client and uh she said you know was + + + align:start position:0% +client and uh she said you know was +something about calculating acid rain + + align:start position:0% +something about calculating acid rain + + + align:start position:0% +something about calculating acid rain +falls on uh soil and then from there the + + align:start position:0% +falls on uh soil and then from there the + + + align:start position:0% +falls on uh soil and then from there the +stuff leeches into a river but uh things + + align:start position:0% +stuff leeches into a river but uh things + + + align:start position:0% +stuff leeches into a river but uh things +happen to it on the way the soil + + align:start position:0% +happen to it on the way the soil + + + align:start position:0% +happen to it on the way the soil +combines with it in various ways reduces + + align:start position:0% +combines with it in various ways reduces + + + align:start position:0% +combines with it in various ways reduces +the acidity and things happen chemical + + align:start position:0% +the acidity and things happen chemical + + + align:start position:0% +the acidity and things happen chemical +reactions take place blah blah blah blah + + align:start position:0% +reactions take place blah blah blah blah + + + align:start position:0% +reactions take place blah blah blah blah +anyway she said well then they + + align:start position:0% +anyway she said well then they + + + align:start position:0% +anyway she said well then they +calculated in the end how much the water + + align:start position:0% +calculated in the end how much the water + + + align:start position:0% +calculated in the end how much the water +get the river gets polluted but she said + + align:start position:0% +get the river gets polluted but she said + + + align:start position:0% +get the river gets polluted but she said +but it's a + + align:start position:0% +but it's a + + + align:start position:0% +but it's a +convolution she said well what's the + + align:start position:0% +convolution she said well what's the + + + align:start position:0% +convolution she said well what's the +convolution so I told her she was too + + align:start position:0% +convolution so I told her she was too + + + align:start position:0% +convolution so I told her she was too +young to learn about the convolution and + + align:start position:0% +young to learn about the convolution and + + + align:start position:0% +young to learn about the convolution and +you know so I thought I'd better look it + + align:start position:0% +you know so I thought I'd better look it + + + align:start position:0% +you know so I thought I'd better look it +up first uh I mean I of course knew what + + align:start position:0% +up first uh I mean I of course knew what + + + align:start position:0% +up first uh I mean I of course knew what +the convolution was but I was a little + + align:start position:0% +the convolution was but I was a little + + + align:start position:0% +the convolution was but I was a little +puzzled at that application of it so I + + align:start position:0% +puzzled at that application of it so I + + + align:start position:0% +puzzled at that application of it so I +read the paper it was interesting and I + + align:start position:0% +read the paper it was interesting and I + + + align:start position:0% +read the paper it was interesting and I +uh in thinking about it uh I then other + + align:start position:0% +uh in thinking about it uh I then other + + + align:start position:0% +uh in thinking about it uh I then other +people have come to me you know some guy + + align:start position:0% +people have come to me you know some guy + + + align:start position:0% +people have come to me you know some guy +with a problem about they drilled ice + + align:start position:0% +with a problem about they drilled ice + + + align:start position:0% +with a problem about they drilled ice +cores in the North Pole and uh from the + + align:start position:0% +cores in the North Pole and uh from the + + + align:start position:0% +cores in the North Pole and uh from the +radioactive carbon and so on they were + + align:start position:0% +radioactive carbon and so on they were + + + align:start position:0% +radioactive carbon and so on they were +deducing various things about the + + align:start position:0% +deducing various things about the + + + align:start position:0% +deducing various things about the +climate you know 60 billion years ago + + align:start position:0% +climate you know 60 billion years ago + + + align:start position:0% +climate you know 60 billion years ago +and it was all convolution he asked me + + align:start position:0% +and it was all convolution he asked me + + + align:start position:0% +and it was all convolution he asked me +if I could explain that to him so let me + + align:start position:0% +if I could explain that to him so let me + + + align:start position:0% +if I could explain that to him so let me +give you uh a sort of an allpurpose + + align:start position:0% +give you uh a sort of an allpurpose + + + align:start position:0% +give you uh a sort of an allpurpose +thing a simple all purpose model which + + align:start position:0% +thing a simple all purpose model which + + + align:start position:0% +thing a simple all purpose model which +can be adapted which is a very good way + + align:start position:0% +can be adapted which is a very good way + + + align:start position:0% +can be adapted which is a very good way +I of thinking of the convolution in my + + align:start position:0% + + + + align:start position:0% + +opinion it's a problem of radioactive + + align:start position:0% + + + + align:start position:0% + +dumping it's in the notes by the way uh + + align:start position:0% +dumping it's in the notes by the way uh + + + align:start position:0% +dumping it's in the notes by the way uh +so I'm just uh if you want to take a + + align:start position:0% +so I'm just uh if you want to take a + + + align:start position:0% +so I'm just uh if you want to take a +chance uh and just listen to what I'm + + align:start position:0% +chance uh and just listen to what I'm + + + align:start position:0% +chance uh and just listen to what I'm +saying rather than scribbling everything + + align:start position:0% +saying rather than scribbling everything + + + align:start position:0% +saying rather than scribbling everything +down maybe it's a good you'll be able to + + align:start position:0% +down maybe it's a good you'll be able to + + + align:start position:0% +down maybe it's a good you'll be able to +figured out the notes also so the + + align:start position:0% +figured out the notes also so the + + + align:start position:0% +figured out the notes also so the +problem is we have some Factory or some + + align:start position:0% +problem is we have some Factory or some + + + align:start position:0% +problem is we have some Factory or some +a nuclear plant or something like that + + align:start position:0% +a nuclear plant or something like that + + + align:start position:0% +a nuclear plant or something like that +it's producing nuclear material + + align:start position:0% +it's producing nuclear material + + + align:start position:0% +it's producing nuclear material +radioactive waste certain not always at + + align:start position:0% +radioactive waste certain not always at + + + align:start position:0% +radioactive waste certain not always at +the same rate uh and then it carts it + + align:start position:0% +the same rate uh and then it carts it + + + align:start position:0% +the same rate uh and then it carts it +and dumps it on a pile somewhere so + + align:start position:0% +and dumps it on a pile somewhere so + + + align:start position:0% +and dumps it on a pile somewhere so +radioactive + + align:start position:0% + + + + align:start position:0% + +waste is dumped and there's a dumping + + align:start position:0% +waste is dumped and there's a dumping + + + align:start position:0% +waste is dumped and there's a dumping +function I'll call that F of T the dump + + align:start position:0% +function I'll call that F of T the dump + + + align:start position:0% +function I'll call that F of T the dump +rate + + align:start position:0% + + + + align:start position:0% + +rate That's The Dumping rate let's say t + + align:start position:0% +rate That's The Dumping rate let's say t + + + align:start position:0% +rate That's The Dumping rate let's say t +is in years you like to have units and + + align:start position:0% +is in years you like to have units and + + + align:start position:0% +is in years you like to have units and +quantity kilograms I don't know whatever + + align:start position:0% +quantity kilograms I don't know whatever + + + align:start position:0% +quantity kilograms I don't know whatever +whatever you want uh now what does The + + align:start position:0% +whatever you want uh now what does The + + + align:start position:0% +whatever you want uh now what does The +Dumping rate + + align:start position:0% +Dumping rate + + + align:start position:0% +Dumping rate +mean The Dumping rate + + align:start position:0% +mean The Dumping rate + + + align:start position:0% +mean The Dumping rate +means that if I on the time axis if I + + align:start position:0% +means that if I on the time axis if I + + + align:start position:0% +means that if I on the time axis if I +have two times which are close together + + align:start position:0% +have two times which are close together + + + align:start position:0% +have two times which are close together +for example two successive days a new + + align:start position:0% +for example two successive days a new + + + align:start position:0% +for example two successive days a new +midnight on two successive days then + + align:start position:0% +midnight on two successive days then + + + align:start position:0% +midnight on two successive days then +there's a time interval between them + + align:start position:0% +there's a time interval between them + + + align:start position:0% +there's a time interval between them +I'll call that delta + + align:start position:0% +I'll call that delta + + + align:start position:0% +I'll call that delta +T to say The Dumping rate is f of t + + align:start position:0% +T to say The Dumping rate is f of t + + + align:start position:0% +T to say The Dumping rate is f of t +means that the amount + + align:start position:0% + + + + align:start position:0% + +dumped in the in this time interval in + + align:start position:0% +dumped in the in this time interval in + + + align:start position:0% +dumped in the in this time interval in +the time interval from TI to TI + one is + + align:start position:0% +the time interval from TI to TI + one is + + + align:start position:0% +the time interval from TI to TI + one is +approximately not exactly because the + + align:start position:0% +approximately not exactly because the + + + align:start position:0% +approximately not exactly because the +damping The Dumping rate isn't even + + align:start position:0% +damping The Dumping rate isn't even + + + align:start position:0% +damping The Dumping rate isn't even +constant within this time interval uh + + align:start position:0% +constant within this time interval uh + + + align:start position:0% +constant within this time interval uh +but it's approximately The Dumping rate + + align:start position:0% +but it's approximately The Dumping rate + + + align:start position:0% +but it's approximately The Dumping rate +times the + + align:start position:0% +times the + + + align:start position:0% +times the +time over which The Dumping was taking + + align:start position:0% + + + + align:start position:0% + +place that's what I mean by The Dump + + align:start position:0% +place that's what I mean by The Dump + + + align:start position:0% +place that's what I mean by The Dump +break and it gets more and more accurate + + align:start position:0% +break and it gets more and more accurate + + + align:start position:0% +break and it gets more and more accurate +the smaller the time interval you + + align:start position:0% +the smaller the time interval you + + + align:start position:0% +the smaller the time interval you +take okay now here's my problem the + + align:start position:0% +take okay now here's my problem the + + + align:start position:0% +take okay now here's my problem the +problem + + align:start position:0% + + + + align:start position:0% + +is start + + align:start position:0% +is start + + + align:start position:0% +is start +dumping at time tal + + align:start position:0% +dumping at time tal + + + align:start position:0% +dumping at time tal +0 at time tal + + align:start position:0% + + + + align:start position:0% + +T how much radioactive waste is in the + + align:start position:0% + + + + align:start position:0% + +pile now what makes that problem + + align:start position:0% +pile now what makes that problem + + + align:start position:0% +pile now what makes that problem +slightly complicated is + + align:start position:0% +slightly complicated is + + + align:start position:0% +slightly complicated is +radioactive waste decays if I put some + + align:start position:0% +radioactive waste decays if I put some + + + align:start position:0% +radioactive waste decays if I put some +at at certain day and then go back + + align:start position:0% +at at certain day and then go back + + + align:start position:0% +at at certain day and then go back +several months later I don't and + + align:start position:0% +several months later I don't and + + + align:start position:0% +several months later I don't and +nothing's happened in between I don't + + align:start position:0% +nothing's happened in between I don't + + + align:start position:0% +nothing's happened in between I don't +have the same amount that I dumped + + align:start position:0% +have the same amount that I dumped + + + align:start position:0% +have the same amount that I dumped +because some of a fraction of it decayed + + align:start position:0% +because some of a fraction of it decayed + + + align:start position:0% +because some of a fraction of it decayed +I have less and our answer to the + + align:start position:0% +I have less and our answer to the + + + align:start position:0% +I have less and our answer to the +problem must take account of for each + + align:start position:0% +problem must take account of for each + + + align:start position:0% +problem must take account of for each +piece of waste how long it has been in + + align:start position:0% +piece of waste how long it has been in + + + align:start position:0% +piece of waste how long it has been in +the pile because that takes account of + + align:start position:0% +the pile because that takes account of + + + align:start position:0% +the pile because that takes account of +how long it had to Decay and what ends + + align:start position:0% +how long it had to Decay and what ends + + + align:start position:0% +how long it had to Decay and what ends +up what it ends up as so the + + align:start position:0% +up what it ends up as so the + + + align:start position:0% +up what it ends up as so the +calculation the essential part of the + + align:start position:0% +calculation the essential part of the + + + align:start position:0% +calculation the essential part of the +calculation will be that if you have an + + align:start position:0% +calculation will be that if you have an + + + align:start position:0% +calculation will be that if you have an +initial amount of this + + align:start position:0% + + + + align:start position:0% + +substance and it decays for a Time + + align:start position:0% + + + + align:start position:0% + +T this is the amount left at time + + align:start position:0% + + + + align:start position:0% + +t + + align:start position:0% + + + + align:start position:0% + +you know this is a law of radioactive + + align:start position:0% +you know this is a law of radioactive + + + align:start position:0% +you know this is a law of radioactive +decay you knew that coming into 1803 + + align:start position:0% +decay you knew that coming into 1803 + + + align:start position:0% +decay you knew that coming into 1803 +although it's of course a simple + + align:start position:0% +although it's of course a simple + + + align:start position:0% +although it's of course a simple +differential equation which produces it + + align:start position:0% +differential equation which produces it + + + align:start position:0% +differential equation which produces it +but I'll assume you simply know the + + align:start position:0% +but I'll assume you simply know the + + + align:start position:0% +but I'll assume you simply know the +answer K depends on the material so I'm + + align:start position:0% +answer K depends on the material so I'm + + + align:start position:0% +answer K depends on the material so I'm +going to assume that the uh nuclear + + align:start position:0% +going to assume that the uh nuclear + + + align:start position:0% +going to assume that the uh nuclear +plant dumps the same radioactive + + align:start position:0% +plant dumps the same radioactive + + + align:start position:0% +plant dumps the same radioactive +substance each time it's only one + + align:start position:0% +substance each time it's only one + + + align:start position:0% +substance each time it's only one +substance I'm calculating and K is it so + + align:start position:0% +substance I'm calculating and K is it so + + + align:start position:0% +substance I'm calculating and K is it so +assume the K is + + align:start position:0% +assume the K is + + + align:start position:0% +assume the K is +fixed I don't have to change from one K + + align:start position:0% +fixed I don't have to change from one K + + + align:start position:0% +fixed I don't have to change from one K +from one material to a k for another + + align:start position:0% +from one material to a k for another + + + align:start position:0% +from one material to a k for another +because it's mixing up the + + align:start position:0% +because it's mixing up the + + + align:start position:0% +because it's mixing up the +stuff just one material okay and now + + align:start position:0% +stuff just one material okay and now + + + align:start position:0% +stuff just one material okay and now +let's calculate it here's the idea I'll + + align:start position:0% +let's calculate it here's the idea I'll + + + align:start position:0% +let's calculate it here's the idea I'll +take the txis but now I'm going to + + align:start position:0% +take the txis but now I'm going to + + + align:start position:0% +take the txis but now I'm going to +change its name to the U axis you'll see + + align:start position:0% +change its name to the U axis you'll see + + + align:start position:0% +change its name to the U axis you'll see +why in just a second starts at + + align:start position:0% +why in just a second starts at + + + align:start position:0% +why in just a second starts at +zero I'm interested in what's happening + + align:start position:0% +zero I'm interested in what's happening + + + align:start position:0% +zero I'm interested in what's happening +at the time T how much is left at time T + + align:start position:0% +at the time T how much is left at time T + + + align:start position:0% +at the time T how much is left at time T +so I'm going to divide up the interval + + align:start position:0% +so I'm going to divide up the interval + + + align:start position:0% +so I'm going to divide up the interval +from 0 to T on this time axis to well + + align:start position:0% +from 0 to T on this time axis to well + + + align:start position:0% +from 0 to T on this time axis to well +here's u0o the starting point U1 + + align:start position:0% +here's u0o the starting point U1 + + + align:start position:0% +here's u0o the starting point U1 +U2 uh let's make this U1 + + align:start position:0% +U2 uh let's make this U1 + + + align:start position:0% +U2 uh let's make this U1 +U oh curses U + + align:start position:0% +U oh curses U + + + align:start position:0% +U oh curses U +Want U two u3 and so on let's call this + + align:start position:0% +Want U two u3 and so on let's call this + + + align:start position:0% +Want U two u3 and so on let's call this +uh + + align:start position:0% + + + + align:start position:0% + +U plus it doesn't + + align:start position:0% +U plus it doesn't + + + align:start position:0% +U plus it doesn't +matter okay now the + + align:start position:0% +matter okay now the + + + align:start position:0% +matter okay now the +amount + + align:start position:0% + + + + align:start position:0% + +so what I'm going to do is look at the + + align:start position:0% +so what I'm going to do is look at the + + + align:start position:0% +so what I'm going to do is look at the +amount uh take a time interval from UI + + align:start position:0% +amount uh take a time interval from UI + + + align:start position:0% +amount uh take a time interval from UI +to UI + 1 this is a time interval delta + + align:start position:0% +to UI + 1 this is a time interval delta + + + align:start position:0% +to UI + 1 this is a time interval delta +T Delta + + align:start position:0% + + + + align:start position:0% + +U divide it up into equal time + + align:start position:0% +U divide it up into equal time + + + align:start position:0% +U divide it up into equal time +intervals so the amount + + align:start position:0% +intervals so the amount + + + align:start position:0% +intervals so the amount +dumped in the time interval from UI to + + align:start position:0% +dumped in the time interval from UI to + + + align:start position:0% +dumped in the time interval from UI to +UI + 1 is equal to approximately F of UI + + align:start position:0% +UI + 1 is equal to approximately F of UI + + + align:start position:0% +UI + 1 is equal to approximately F of UI +the dump function there times Delta U we + + align:start position:0% +the dump function there times Delta U we + + + align:start position:0% +the dump function there times Delta U we +calculated that before that's what the + + align:start position:0% +calculated that before that's what the + + + align:start position:0% +calculated that before that's what the +meaning of The Dumping + + align:start position:0% + + + + align:start position:0% + +rate by time T how much has it decayed + + align:start position:0% +rate by time T how much has it decayed + + + align:start position:0% +rate by time T how much has it decayed +to it has decayed how much is left in + + align:start position:0% +to it has decayed how much is left in + + + align:start position:0% +to it has decayed how much is left in +other + + align:start position:0% + + + + align:start position:0% + +words well this is the starting + + align:start position:0% +words well this is the starting + + + align:start position:0% +words well this is the starting +amount so the answer is going to be it's + + align:start position:0% +amount so the answer is going to be it's + + + align:start position:0% +amount so the answer is going to be it's +F of U + + align:start position:0% +F of U + + + align:start position:0% +F of U +* Delta U + + align:start position:0% +* Delta U + + + align:start position:0% +* Delta U +times this factor which tells how how + + align:start position:0% +times this factor which tells how how + + + align:start position:0% +times this factor which tells how how +much it decay now so times so this is + + align:start position:0% +much it decay now so times so this is + + + align:start position:0% +much it decay now so times so this is +the starting amount at time + + align:start position:0% +the starting amount at time + + + align:start position:0% +the starting amount at time +UI that's what it was first dumped and + + align:start position:0% +UI that's what it was first dumped and + + + align:start position:0% +UI that's what it was first dumped and +this is the amount that was dumped time + + align:start position:0% +this is the amount that was dumped time + + + align:start position:0% +this is the amount that was dumped time +multiply that by e to the minus K times + + align:start position:0% +multiply that by e to the minus K times + + + align:start position:0% +multiply that by e to the minus K times +now what should I put up in there I have + + align:start position:0% +now what should I put up in there I have + + + align:start position:0% +now what should I put up in there I have +to put the length of time that it had to + + align:start position:0% +to put the length of time that it had to + + + align:start position:0% +to put the length of time that it had to +decay + + align:start position:0% +decay + + + align:start position:0% +decay +what is the length of time that it had + + align:start position:0% +what is the length of time that it had + + + align:start position:0% +what is the length of time that it had +to Decay it was dumped at UI I'm looking + + align:start position:0% +to Decay it was dumped at UI I'm looking + + + align:start position:0% +to Decay it was dumped at UI I'm looking +at time T it decayed + + align:start position:0% +at time T it decayed + + + align:start position:0% +at time T it decayed +for the time length T minus + + align:start position:0% + + + + align:start position:0% + +UI the length of + + align:start position:0% +UI the length of + + + align:start position:0% +UI the length of +time it + + align:start position:0% + + + + align:start position:0% + +had it on the pile + + align:start position:0% + + + + align:start position:0% + +so the stuff that was dumped in this + + align:start position:0% +so the stuff that was dumped in this + + + align:start position:0% +so the stuff that was dumped in this +time interval when I at time T when I + + align:start position:0% +time interval when I at time T when I + + + align:start position:0% +time interval when I at time T when I +come to look at it this is how much of + + align:start position:0% +come to look at it this is how much of + + + align:start position:0% +come to look at it this is how much of +it is left and now all I have to do is + + align:start position:0% +it is left and now all I have to do is + + + align:start position:0% +it is left and now all I have to do is +add up that that quantity for this time + + align:start position:0% +add up that that quantity for this time + + + align:start position:0% +add up that that quantity for this time +the stuff that was dumped in this time + + align:start position:0% +the stuff that was dumped in this time + + + align:start position:0% +the stuff that was dumped in this time +interval plus the stuff dumped then plus + + align:start position:0% +interval plus the stuff dumped then plus + + + align:start position:0% +interval plus the stuff dumped then plus +and so on all the way up to the stuff + + align:start position:0% +and so on all the way up to the stuff + + + align:start position:0% +and so on all the way up to the stuff +that was dumped yesterday and the answer + + align:start position:0% +that was dumped yesterday and the answer + + + align:start position:0% +that was dumped yesterday and the answer +will be + + align:start position:0% +will be + + + align:start position:0% +will be +therefore + + align:start position:0% +therefore + + + align:start position:0% +therefore +the answer will be the total + + align:start position:0% + + + + align:start position:0% + +amount left at time + + align:start position:0% +amount left at time + + + align:start position:0% +amount left at time +T that is that is not yet + + align:start position:0% + + + + align:start position:0% + +decayed will be approximately you add up + + align:start position:0% +decayed will be approximately you add up + + + align:start position:0% +decayed will be approximately you add up +the amount coming from the first time + + align:start position:0% +the amount coming from the first time + + + align:start position:0% +the amount coming from the first time +interval plus the amount coming and so + + align:start position:0% +interval plus the amount coming and so + + + align:start position:0% +interval plus the amount coming and so +on so it will be F of UI I'll save the + + align:start position:0% +on so it will be F of UI I'll save the + + + align:start position:0% +on so it will be F of UI I'll save the +Delta U for the n * eus K * tus UI Del + + align:start position:0% +Delta U for the n * eus K * tus UI Del + + + align:start position:0% +Delta U for the n * eus K * tus UI Del +Delta U so these two parts represent the + + align:start position:0% +Delta U so these two parts represent the + + + align:start position:0% +Delta U so these two parts represent the +amount dumped and this is the Decay + + align:start position:0% +amount dumped and this is the Decay + + + align:start position:0% +amount dumped and this is the Decay +factor and I add those up as I runs from + + align:start position:0% +factor and I add those up as I runs from + + + align:start position:0% +factor and I add those up as I runs from +well where did I start from one to then + + align:start position:0% +well where did I start from one to then + + + align:start position:0% +well where did I start from one to then +let's + + align:start position:0% + + + + align:start position:0% + +say and now let delta T go to zero in + + align:start position:0% +say and now let delta T go to zero in + + + align:start position:0% +say and now let delta T go to zero in +other words make this more AC Delta U go + + align:start position:0% +other words make this more AC Delta U go + + + align:start position:0% +other words make this more AC Delta U go +to zero make this more accurate by + + align:start position:0% +to zero make this more accurate by + + + align:start position:0% +to zero make this more accurate by +taking finer and finer subdiv in other + + align:start position:0% +taking finer and finer subdiv in other + + + align:start position:0% +taking finer and finer subdiv in other +words instead of looking every month to + + align:start position:0% +words instead of looking every month to + + + align:start position:0% +words instead of looking every month to +see how much was dump let's look every + + align:start position:0% +see how much was dump let's look every + + + align:start position:0% +see how much was dump let's look every +week every day and so on to make this + + align:start position:0% +week every day and so on to make this + + + align:start position:0% +week every day and so on to make this +calculation more accurate and the answer + + align:start position:0% +calculation more accurate and the answer + + + align:start position:0% +calculation more accurate and the answer +is this + + align:start position:0% +is this + + + align:start position:0% +is this +approaches the exact amount which will + + align:start position:0% +approaches the exact amount which will + + + align:start position:0% +approaches the exact amount which will +be the integral this sum is a remon sum + + align:start position:0% +be the integral this sum is a remon sum + + + align:start position:0% +be the integral this sum is a remon sum +it approaches the integral from zero to + + align:start position:0% +it approaches the integral from zero to + + + align:start position:0% +it approaches the integral from zero to +well I'm adding it up from + + align:start position:0% +well I'm adding it up from + + + align:start position:0% +well I'm adding it up from +U 1al 0 to u n = t the final value so it + + align:start position:0% +U 1al 0 to u n = t the final value so it + + + align:start position:0% +U 1al 0 to u n = t the final value so it +will be the integral from the starting + + align:start position:0% +will be the integral from the starting + + + align:start position:0% +will be the integral from the starting +point to the ending point of f of U + + align:start position:0% +point to the ending point of f of U + + + align:start position:0% +point to the ending point of f of U +eus K * tus U + + align:start position:0% +eus K * tus U + + + align:start position:0% +eus K * tus U +du that's the answer to the problem it's + + align:start position:0% +du that's the answer to the problem it's + + + align:start position:0% +du that's the answer to the problem it's +given by this rather funny looking + + align:start position:0% +given by this rather funny looking + + + align:start position:0% +given by this rather funny looking +integral but from this point of view + + align:start position:0% +integral but from this point of view + + + align:start position:0% +integral but from this point of view +it's entirely natural It's a combination + + align:start position:0% +it's entirely natural It's a combination + + + align:start position:0% +it's entirely natural It's a combination +of The Dumping function this doesn't + + align:start position:0% +of The Dumping function this doesn't + + + align:start position:0% +of The Dumping function this doesn't +care what the material was it only wants + + align:start position:0% +care what the material was it only wants + + + align:start position:0% +care what the material was it only wants +to know how much was put on every day + + align:start position:0% +to know how much was put on every day + + + align:start position:0% +to know how much was put on every day +and this part which doesn't care how + + align:start position:0% +and this part which doesn't care how + + + align:start position:0% +and this part which doesn't care how +much was put on each day it just is an + + align:start position:0% +much was put on each day it just is an + + + align:start position:0% +much was put on each day it just is an +intrinsic constant of the materal + + align:start position:0% +intrinsic constant of the materal + + + align:start position:0% +intrinsic constant of the materal +material involving its Decay rate and + + align:start position:0% +material involving its Decay rate and + + + align:start position:0% +material involving its Decay rate and +this total thing represents the total + + align:start position:0% +this total thing represents the total + + + align:start position:0% +this total thing represents the total +amount and that is what is it it's the + + align:start position:0% +amount and that is what is it it's the + + + align:start position:0% +amount and that is what is it it's the +convolution of f of t with what + + align:start position:0% +convolution of f of t with what + + + align:start position:0% +convolution of f of t with what +function e to + + align:start position:0% + + + + align:start position:0% + +the minus + + align:start position:0% +the minus + + + align:start position:0% +the minus +KT it's the convolution of The Dumping + + align:start position:0% +KT it's the convolution of The Dumping + + + align:start position:0% +KT it's the convolution of The Dumping +function and the Decay function and the + + align:start position:0% +function and the Decay function and the + + + align:start position:0% +function and the Decay function and the +convolution is exactly the operation + + align:start position:0% +convolution is exactly the operation + + + align:start position:0% +convolution is exactly the operation +that you have to have to do that okay + + align:start position:0% +that you have to have to do that okay + + + align:start position:0% +that you have to have to do that okay +okay uh so I think this is the most + + align:start position:0% +okay uh so I think this is the most + + + align:start position:0% +okay uh so I think this is the most +intuitive approach physical approach to + + align:start position:0% +intuitive approach physical approach to + + + align:start position:0% +intuitive approach physical approach to +the meaning of this of the convolution + + align:start position:0% +the meaning of this of the convolution + + + align:start position:0% +the meaning of this of the convolution +in this particular you say well that's + + align:start position:0% +in this particular you say well that's + + + align:start position:0% +in this particular you say well that's +very special okay so it tells me what + + align:start position:0% +very special okay so it tells me what + + + align:start position:0% +very special okay so it tells me what +the meaning of a convolution with a an + + align:start position:0% +the meaning of a convolution with a an + + + align:start position:0% +the meaning of a convolution with a an +exponential is but what about the + + align:start position:0% +exponential is but what about the + + + align:start position:0% +exponential is but what about the +convolution with all the other functions + + align:start position:0% +convolution with all the other functions + + + align:start position:0% +convolution with all the other functions +we're going to have to use in this + + align:start position:0% +we're going to have to use in this + + + align:start position:0% +we're going to have to use in this +course they can all be interpreted just + + align:start position:0% +course they can all be interpreted just + + + align:start position:0% +course they can all be interpreted just +by being a little flexible in your + + align:start position:0% +by being a little flexible in your + + + align:start position:0% +by being a little flexible in your +approach I'll give you two examples of + + align:start position:0% +approach I'll give you two examples of + + + align:start position:0% +approach I'll give you two examples of +this well you'll three first of all uh I + + align:start position:0% +this well you'll three first of all uh I + + + align:start position:0% +this well you'll three first of all uh I +use it for a i in the problem set I + + align:start position:0% +use it for a i in the problem set I + + + align:start position:0% +use it for a i in the problem set I +asked you about a bank account uh that's + + align:start position:0% +asked you about a bank account uh that's + + + align:start position:0% +asked you about a bank account uh that's +not something any of you are interested + + align:start position:0% +not something any of you are interested + + + align:start position:0% +not something any of you are interested +in okay so how about uh suppose I said I + + align:start position:0% +in okay so how about uh suppose I said I + + + align:start position:0% +in okay so how about uh suppose I said I +dump + + align:start position:0% + + + + align:start position:0% + +garbage undecayed + + align:start position:0% +garbage undecayed + + + align:start position:0% +garbage undecayed +undecaying so something that doesn't + + align:start position:0% +undecaying so something that doesn't + + + align:start position:0% +undecaying so something that doesn't +Decay at + + align:start position:0% +Decay at + + + align:start position:0% +Decay at +all what's the answer going to be well + + align:start position:0% +all what's the answer going to be well + + + align:start position:0% +all what's the answer going to be well +the calculation will be exactly the same + + align:start position:0% +the calculation will be exactly the same + + + align:start position:0% +the calculation will be exactly the same +there'll be it'll be the convolution of + + align:start position:0% +there'll be it'll be the convolution of + + + align:start position:0% +there'll be it'll be the convolution of +The Dumping function the only difference + + align:start position:0% +The Dumping function the only difference + + + align:start position:0% +The Dumping function the only difference +is that now the garbage isn't going to + + align:start position:0% +is that now the garbage isn't going to + + + align:start position:0% +is that now the garbage isn't going to +Decay so no matter how long it's left + + align:start position:0% +Decay so no matter how long it's left + + + align:start position:0% +Decay so no matter how long it's left +the same amount is going to be left at + + align:start position:0% +the same amount is going to be left at + + + align:start position:0% +the same amount is going to be left at +the end in other words I don't want the + + align:start position:0% +the end in other words I don't want the + + + align:start position:0% +the end in other words I don't want the +an exponential decay function I want the + + align:start position:0% +an exponential decay function I want the + + + align:start position:0% +an exponential decay function I want the +function one the constant function one + + align:start position:0% +function one the constant function one + + + align:start position:0% +function one the constant function one +because once I stick it on the pile + + align:start position:0% +because once I stick it on the pile + + + align:start position:0% +because once I stick it on the pile +nothing happens to it it just stays + + align:start position:0% +nothing happens to it it just stays + + + align:start position:0% +nothing happens to it it just stays +there so it's going to be the + + align:start position:0% +there so it's going to be the + + + align:start position:0% +there so it's going to be the +convolution of this one because this is + + align:start position:0% +convolution of this one because this is + + + align:start position:0% +convolution of this one because this is +constant it's undecayed + + align:start position:0% + + + + align:start position:0% + +this by The Identical reasoning and so + + align:start position:0% +this by The Identical reasoning and so + + + align:start position:0% +this by The Identical reasoning and so +what's the answer going to be it's going + + align:start position:0% +what's the answer going to be it's going + + + align:start position:0% +what's the answer going to be it's going +to be the integral from0 to T of f of U + + align:start position:0% +to be the integral from0 to T of f of U + + + align:start position:0% +to be the integral from0 to T of f of U +du now that's an 1801 problem if I dump + + align:start position:0% +du now that's an 1801 problem if I dump + + + align:start position:0% +du now that's an 1801 problem if I dump +with a dumping rate F of U and I dump + + align:start position:0% +with a dumping rate F of U and I dump + + + align:start position:0% +with a dumping rate F of U and I dump +from Time Zero to time T how much to is + + align:start position:0% +from Time Zero to time T how much to is + + + align:start position:0% +from Time Zero to time T how much to is +on the pile they don't give it they + + align:start position:0% +on the pile they don't give it they + + + align:start position:0% +on the pile they don't give it they +always give velocity problems and + + align:start position:0% +always give velocity problems and + + + align:start position:0% +always give velocity problems and +problems of how to slice up red lows and + + align:start position:0% +problems of how to slice up red lows and + + + align:start position:0% +problems of how to slice up red lows and +stuff like that but but this is a real + + align:start position:0% +stuff like that but but this is a real + + + align:start position:0% +stuff like that but but this is a real +life problem if that's the dumping rate + + align:start position:0% +life problem if that's the dumping rate + + + align:start position:0% +life problem if that's the dumping rate +and you dump for T days from zero to + + align:start position:0% +and you dump for T days from zero to + + + align:start position:0% +and you dump for T days from zero to +time0 time T how much you have left at + + align:start position:0% +time0 time T how much you have left at + + + align:start position:0% +time0 time T how much you have left at +the end answer the integral of f of U du + + align:start position:0% +the end answer the integral of f of U du + + + align:start position:0% +the end answer the integral of f of U du +from 0 to + + align:start position:0% +from 0 to + + + align:start position:0% +from 0 to +T I'll give you another example suppose + + align:start position:0% +T I'll give you another example suppose + + + align:start position:0% +T I'll give you another example suppose +I wanted a dumping suppose I wanted a + + align:start position:0% +I wanted a dumping suppose I wanted a + + + align:start position:0% +I wanted a dumping suppose I wanted a +function uh wanted to interpret + + align:start position:0% +function uh wanted to interpret + + + align:start position:0% +function uh wanted to interpret +something uh which grows like T for + + align:start position:0% + + + + align:start position:0% + +instance or I want is a physical + + align:start position:0% +instance or I want is a physical + + + align:start position:0% +instance or I want is a physical +interpretation well I have to think of + + align:start position:0% +interpretation well I have to think of + + + align:start position:0% +interpretation well I have to think of +I'm making a pile of something you know + + align:start position:0% +I'm making a pile of something you know + + + align:start position:0% +I'm making a pile of something you know +a metaphorical pile we don't actually + + align:start position:0% +a metaphorical pile we don't actually + + + align:start position:0% +a metaphorical pile we don't actually +have to make a physical pile uh and the + + align:start position:0% +have to make a physical pile uh and the + + + align:start position:0% +have to make a physical pile uh and the +things should be growing like tea well + + align:start position:0% +things should be growing like tea well + + + align:start position:0% +things should be growing like tea well +what grows like tea uh not bacteria they + + align:start position:0% +what grows like tea uh not bacteria they + + + align:start position:0% +what grows like tea uh not bacteria they +grow exponentially let's I was before + + align:start position:0% +grow exponentially let's I was before + + + align:start position:0% +grow exponentially let's I was before +the electure I was trying to think + + align:start position:0% +the electure I was trying to think + + + align:start position:0% +the electure I was trying to think +something so I came up with chickens I'm + + align:start position:0% +something so I came up with chickens I'm + + + align:start position:0% +something so I came up with chickens I'm +sure on a chicken farm little baby + + align:start position:0% +sure on a chicken farm little baby + + + align:start position:0% +sure on a chicken farm little baby +chickens grow linearly all little animal + + align:start position:0% +chickens grow linearly all little animal + + + align:start position:0% +chickens grow linearly all little animal +all little animals anyway I've observed + + align:start position:0% +all little animals anyway I've observed + + + align:start position:0% +all little animals anyway I've observed +that babies grow linearly at at least + + align:start position:0% +that babies grow linearly at at least + + + align:start position:0% +that babies grow linearly at at least +for a while thank God after a while they + + align:start position:0% +for a while thank God after a while they + + + align:start position:0% +for a while thank God after a while they +tap her off but uh but but in the + + align:start position:0% +tap her off but uh but but in the + + + align:start position:0% +tap her off but uh but but in the +beginning you know they eat every four + + align:start position:0% +beginning you know they eat every four + + + align:start position:0% +beginning you know they eat every four +hours or whatever and they eat the same + + align:start position:0% +hours or whatever and they eat the same + + + align:start position:0% +hours or whatever and they eat the same +amount pretty much and that adds up uh + + align:start position:0% +amount pretty much and that adds up uh + + + align:start position:0% +amount pretty much and that adds up uh +so it's uh so let's suppose this + + align:start position:0% +so it's uh so let's suppose this + + + align:start position:0% +so it's uh so let's suppose this +represents the growth lyar growth of + + align:start position:0% + + + + align:start position:0% + +chickens of baby chicks baby chick that + + align:start position:0% +chickens of baby chicks baby chick that + + + align:start position:0% +chickens of baby chicks baby chick that +makes them sound + + align:start position:0% + + + + align:start position:0% + +cuter less offensive okay so a farmer a + + align:start position:0% +cuter less offensive okay so a farmer a + + + align:start position:0% +cuter less offensive okay so a farmer a +chicken farmer or whatever they call + + align:start position:0% +chicken farmer or whatever they call + + + align:start position:0% +chicken farmer or whatever they call +them uh is starting a new brood so + + align:start position:0% +them uh is starting a new brood so + + + align:start position:0% +them uh is starting a new brood so +anyway the hens lay at a certain rate + + align:start position:0% +anyway the hens lay at a certain rate + + + align:start position:0% +anyway the hens lay at a certain rate +and each of those are incubated and + + align:start position:0% +and each of those are incubated and + + + align:start position:0% +and each of those are incubated and +after all a couple months they turn into + + align:start position:0% +after all a couple months they turn into + + + align:start position:0% +after all a couple months they turn into +a little baby chicks come out uh so this + + align:start position:0% +a little baby chicks come out uh so this + + + align:start position:0% +a little baby chicks come out uh so this +will be the rate the production rate for + + align:start position:0% +will be the rate the production rate for + + + align:start position:0% +will be the rate the production rate for +new + + align:start position:0% + + + + align:start position:0% + +chickens okay and it will be the + + align:start position:0% +chickens okay and it will be the + + + align:start position:0% +chickens okay and it will be the +convolution which will be tell you at + + align:start position:0% +convolution which will be tell you at + + + align:start position:0% +convolution which will be tell you at +time t uh the number of kilograms we + + align:start position:0% +time t uh the number of kilograms we + + + align:start position:0% +time t uh the number of kilograms we +better do this in kilograms I'm afraid + + align:start position:0% +better do this in kilograms I'm afraid + + + align:start position:0% +better do this in kilograms I'm afraid +uh now that's not as heartless as it + + align:start position:0% +uh now that's not as heartless as it + + + align:start position:0% +uh now that's not as heartless as it +seems uh the number of kilograms of + + align:start position:0% +seems uh the number of kilograms of + + + align:start position:0% +seems uh the number of kilograms of +chickens time + + align:start position:0% +chickens time + + + align:start position:0% +chickens time +te it really isn't heartless because + + align:start position:0% +te it really isn't heartless because + + + align:start position:0% +te it really isn't heartless because +after all why does a why would the + + align:start position:0% +after all why does a why would the + + + align:start position:0% +after all why does a why would the +farmer want to know that well because a + + align:start position:0% +farmer want to know that well because a + + + align:start position:0% +farmer want to know that well because a +certain number of pounds of chicken eat + + align:start position:0% +certain number of pounds of chicken eat + + + align:start position:0% +certain number of pounds of chicken eat +a certain number of pounds of chicken + + align:start position:0% +a certain number of pounds of chicken + + + align:start position:0% +a certain number of pounds of chicken +feed and that's how much he has to dump + + align:start position:0% +feed and that's how much he has to dump + + + align:start position:0% +feed and that's how much he has to dump +uh + + align:start position:0% +uh + + + align:start position:0% +uh +bus have to give them every day that's + + align:start position:0% +bus have to give them every day that's + + + align:start position:0% +bus have to give them every day that's +how he calculates his expenses so he + + align:start position:0% +how he calculates his expenses so he + + + align:start position:0% +how he calculates his expenses so he +will have to know what the convolution + + align:start position:0% +will have to know what the convolution + + + align:start position:0% +will have to know what the convolution +is or better yet he will hire you who + + align:start position:0% +is or better yet he will hire you who + + + align:start position:0% +is or better yet he will hire you who +knows what the convolution is and you'll + + align:start position:0% +knows what the convolution is and you'll + + + align:start position:0% +knows what the convolution is and you'll +be able to tell him okay why don't we + + align:start position:0% +be able to tell him okay why don't we + + + align:start position:0% +be able to tell him okay why don't we +stop there and uh uh go to recitation + + align:start position:0% +stop there and uh uh go to recitation + + + align:start position:0% +stop there and uh uh go to recitation +tomorrow because they'll be doing + + align:start position:0% +tomorrow because they'll be doing + + + align:start position:0% +tomorrow because they'll be doing +important + + align:start position:0% + + + + align:start position:0% + +things \ No newline at end of file diff --git a/3mu47FWEuqA.txt b/3mu47FWEuqA.txt new file mode 100644 index 0000000000000000000000000000000000000000..6702b714936ba10250d65081196d6fc99d83edc1 --- /dev/null +++ b/3mu47FWEuqA.txt @@ -0,0 +1,330 @@ +In this exercise, we'll be +looking at a problem, also + +know as the coupons collector's +problem. + +We have a set of K coupons, +or grades in our case. + +And each time slot +we're revealed + +with one random grade. + +And we'd like to know how long +it would take for us to + +collect all K grades. + +In our case, K is equal to 6. + +Now the key to solving +the problem + +is essentially twofolds. + +First, we'll have to find a way +to intelligently define + +sequence random variables that +captured, essentially, + +stopping time of this process. + +And then we'll employ the idea +of linearity of expectations + +in breaking down this value +in simpler terms. + +So let's get started. + +We'll define Yi as the number +of papers till we see + +the i-th new grade. + + + +What does that mean? + +Well, let's take a look +at an example. + +Suppose, here we have a timeline +from no paper yet, + +first paper, second paper, +third paper, + +so on, and so forth. + +Now, if we got grade A on the +first slot, grade A minus on + +second slot, A again on the +third slot, let's say there's + +a fourth's slot, we got B. + +According to this process, we +see that Y1 is always 1, + +because whatever we got +on the first slot + +will be a new grade. + +Now, Y2 is 2, because +the second paper is, + +again, a new grade. + +On the third paper we got a +grade, which is the same as + +the first grade. + +So that would not +count as any Yi. + +And the third time we saw new +grade would now be paper four. + +According to this notation, +we're interested in knowing + +what is the expected value of E +of Y6, which is the time it + +takes to receive +all six grades. + +So so far this notation isn't +really helping us in solving + +the problem, but kind of just +staying a different way. + +It turns out, it's much easier +to look at the following + +variable derived from the Yis. + +We'll define Xi as the +difference between Yi + +plus 1 minus Yi. + +And in [? words, ?] it says, Xi +is a number of papers you + +need until you see the i plus +1-th new grade, after you have + +received i new grade so far. + +So in this case, X1 will be if +we call 0, Y0, will be the + +difference between Y1 and +Y0, which is always 1-- + +that's X1. + +And the difference between +these two will be X2. + +And the difference between +Y3 and Y2-- + +Sorry. + +It should be Y X0, +1, 2, and so on. + +OK? + +Through this notation we see +that Y6 now can be written as + +the summation of i equal +to 0, 2, 5, X, i. + +So all I did was to break down +i6 into a sequence of + +summation of the differences, +like Y. 6 Minus Y5, Y5 minus + +Y4, and so on. + +It turns out, this expression +will be very useful. + +OK. + +So now that we have the two +variables Y and X, let's see + +if it will be easier to look +at the distribution of X in + +studying this process. + +Let's say, we have seen +a new grade so far-- + +one. + +How many trials would it +take for us to see + +the second new grade? + +It turns out it's +not that hard. + +In this case, we know there is +a total of six grades, and we + +have seen one of them. + +So that leaves us five +more grades that + +we'll potentially see. + +And therefore, on any random +trial after that, there is a + +probability of 5 over 6 that +we'll see a new grade. + +And hence, we know that X1 has +a distribution geometric with + +a success probability, +or a parameter, 5/6. + +Now, more generally, if we +extend this idea further, we + +see that Xi will have a +geometric distribution of + +parameter 6 minus i over 6. + +And this is due to the fact that +so far we have already + +seen i new grades. + +And that will be the success +probability of seeing a + +further new grade. + +So from this expression, we know +that the expected value + +of Xi will simply be the inverse +of the parameter of + +the geometric distribution, +which is 6 over 6 minus i or 6 + +times 1 over 6 minus i. + + + +And now we're ready to compute +a final answer. + +So from this expression we know +expected value of Y6 is + +equal to the expected value of +sum of i equal to 0 to 5 Xi. + + + +And by the linearity of +expectation, we can pull out + +the sum and write it as 2, +5 expected value of Xi. + +Now, since we know that +expective of Xi is the + +following expression. + +We see that this term is equal +to 6 times expected value of i + +equals 0, 5, 1 over 6 minus i. + +Or written in the other way +this is equal to 6 times i + +equal to 0, 2, 5. + +In fact, 1, 2, 5, 1 over i. + +And all I did here was to, +essentially, change the + +variable, so that these two +summations contained exactly + +the same terms. + +And this will give us the +answer, which is 14.7. + +Now, more generally, we can +see that there's nothing + +special about number 6 here. + +We could have substituted 6 with +a number, let's say, K. + +And then we'll get E of YK, +let's say, there's more than + +six labels. + +And this will give us K times +summation i equal to 1, so K + +minus 1, 1 over i. + +Interestingly, it turns out +this quantity has an + +[? asymptotic ?] + +expression that, essentially, +is roughly equal to K times + +the natural logarithm of K. +And this is known as the + +scaling [? la ?] + +for the coupon collector's +problem that says, + +essentially, takes about +K times [? la ?] + +K many trials until we collect +all K coupons. + +And that'll be the end +of the problem. + +See you next time. \ No newline at end of file diff --git a/45X0puB3YK0.txt b/45X0puB3YK0.txt new file mode 100644 index 0000000000000000000000000000000000000000..4bfb5daa81c5f70ef5379dd645758c14719c1589 --- /dev/null +++ b/45X0puB3YK0.txt @@ -0,0 +1,1187 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +view additional materials from hundreds + + align:start position:0% +view additional materials from hundreds + + + align:start position:0% +view additional materials from hundreds +of MIT courses visit mitop coreware at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu in this demonstration we're + + align:start position:0% +ocw.mit.edu in this demonstration we're + + + align:start position:0% +ocw.mit.edu in this demonstration we're +going to illustrate the propagation of + + align:start position:0% +going to illustrate the propagation of + + + align:start position:0% +going to illustrate the propagation of +light in a fiber a glass fiber as we + + align:start position:0% +light in a fiber a glass fiber as we + + + align:start position:0% +light in a fiber a glass fiber as we +know today + + align:start position:0% +know today + + + align:start position:0% +know today +Optical fibers have a lot of low loss + + align:start position:0% +Optical fibers have a lot of low loss + + + align:start position:0% +Optical fibers have a lot of low loss +very low loss of the order of one or two + + align:start position:0% +very low loss of the order of one or two + + + align:start position:0% +very low loss of the order of one or two +DBS per kilometer and of course they're + + align:start position:0% +DBS per kilometer and of course they're + + + align:start position:0% +DBS per kilometer and of course they're +being used for communication as well as + + align:start position:0% +being used for communication as well as + + + align:start position:0% +being used for communication as well as +other applications like + + align:start position:0% +other applications like + + + align:start position:0% +other applications like +sensors so the setup we have is a uh is + + align:start position:0% +sensors so the setup we have is a uh is + + + align:start position:0% +sensors so the setup we have is a uh is +a laser a helium neon laser over here + + align:start position:0% +a laser a helium neon laser over here + + + align:start position:0% +a laser a helium neon laser over here +here's the output from from the laser + + align:start position:0% +here's the output from from the laser + + + align:start position:0% +here's the output from from the laser +we're going to reflect it by this mirror + + align:start position:0% +we're going to reflect it by this mirror + + + align:start position:0% +we're going to reflect it by this mirror +and this + + align:start position:0% +and this + + + align:start position:0% +and this +mirror and then pass it through a lens + + align:start position:0% +mirror and then pass it through a lens + + + align:start position:0% +mirror and then pass it through a lens +this lens over here focuses the light + + align:start position:0% +this lens over here focuses the light + + + align:start position:0% +this lens over here focuses the light +into the fiber end and if we can take a + + align:start position:0% +into the fiber end and if we can take a + + + align:start position:0% +into the fiber end and if we can take a +closeup of what's going on over here + + align:start position:0% +closeup of what's going on over here + + + align:start position:0% +closeup of what's going on over here +what you would see is then a lens this + + align:start position:0% +what you would see is then a lens this + + + align:start position:0% +what you would see is then a lens this +lens then focusing the light and fiber + + align:start position:0% +lens then focusing the light and fiber + + + align:start position:0% +lens then focusing the light and fiber +and the fiber is very close to the + + align:start position:0% +and the fiber is very close to the + + + align:start position:0% +and the fiber is very close to the +lens and then the rest of the fiber is + + align:start position:0% +lens and then the rest of the fiber is + + + align:start position:0% +lens and then the rest of the fiber is +here all right so here is the the rest + + align:start position:0% +here all right so here is the the rest + + + align:start position:0% +here all right so here is the the rest +of the fiber now this fiber uh in fact + + align:start position:0% +of the fiber now this fiber uh in fact + + + align:start position:0% +of the fiber now this fiber uh in fact +what you're seeing over here is the uh + + align:start position:0% +what you're seeing over here is the uh + + + align:start position:0% +what you're seeing over here is the uh +essentially the the plastic jacket the + + align:start position:0% +essentially the the plastic jacket the + + + align:start position:0% +essentially the the plastic jacket the +fiber + + align:start position:0% +fiber + + + align:start position:0% +fiber +core is about four microns in in + + align:start position:0% +core is about four microns in in + + + align:start position:0% +core is about four microns in in +diameter and the cladding is 125 microns + + align:start position:0% +diameter and the cladding is 125 microns + + + align:start position:0% +diameter and the cladding is 125 microns +and the rest that you see here is the is + + align:start position:0% +and the rest that you see here is the is + + + align:start position:0% +and the rest that you see here is the is +the plastic jacket that's why it looks + + align:start position:0% +the plastic jacket that's why it looks + + + align:start position:0% +the plastic jacket that's why it looks +so so visible because it's so thick the + + align:start position:0% +so so visible because it's so thick the + + + align:start position:0% +so so visible because it's so thick the +other end of the fiber then uh goes into + + align:start position:0% +other end of the fiber then uh goes into + + + align:start position:0% +other end of the fiber then uh goes into +this + + align:start position:0% +this + + + align:start position:0% +this +holder and the in a Chuck here it's in a + + align:start position:0% +holder and the in a Chuck here it's in a + + + align:start position:0% +holder and the in a Chuck here it's in a +hole fiber hold in a Chuck and the + + align:start position:0% +hole fiber hold in a Chuck and the + + + align:start position:0% +hole fiber hold in a Chuck and the +output of the + + align:start position:0% +output of the + + + align:start position:0% +output of the +of the fiber then is over here onto this + + align:start position:0% +of the fiber then is over here onto this + + + align:start position:0% +of the fiber then is over here onto this +uh onto this little + + align:start position:0% +uh onto this little + + + align:start position:0% +uh onto this little +screen now if if we can maybe we can + + align:start position:0% +screen now if if we can maybe we can + + + align:start position:0% +screen now if if we can maybe we can +take a close look at the at the fiber + + align:start position:0% +take a close look at the at the fiber + + + align:start position:0% +take a close look at the at the fiber +end + + align:start position:0% +end + + + align:start position:0% +end +here what which + + align:start position:0% +here what which + + + align:start position:0% +here what which +shows that uh what you see over here uh + + align:start position:0% +shows that uh what you see over here uh + + + align:start position:0% +shows that uh what you see over here uh +in fact let me point to it what you see + + align:start position:0% +in fact let me point to it what you see + + + align:start position:0% +in fact let me point to it what you see +over here is the the cladding + + align:start position:0% +over here is the the cladding + + + align:start position:0% +over here is the the cladding +essentially we've stripped the jacket + + align:start position:0% +essentially we've stripped the jacket + + + align:start position:0% +essentially we've stripped the jacket +and what you see here is just the + + align:start position:0% +and what you see here is just the + + + align:start position:0% +and what you see here is just the +clading and this is the 125 microns + + align:start position:0% +clading and this is the 125 microns + + + align:start position:0% +clading and this is the 125 microns +while over here over + + align:start position:0% +while over here over + + + align:start position:0% +while over here over +here is the is the the fiber with the + + align:start position:0% +here is the is the the fiber with the + + + align:start position:0% +here is the is the the fiber with the +plastic with the plastic jacket so when + + align:start position:0% +plastic with the plastic jacket so when + + + align:start position:0% +plastic with the plastic jacket so when +you remove the plastic jacket then you + + align:start position:0% +you remove the plastic jacket then you + + + align:start position:0% +you remove the plastic jacket then you +have essentially what you're seeing is + + align:start position:0% +have essentially what you're seeing is + + + align:start position:0% +have essentially what you're seeing is +the is just the 125 Micron clading all + + align:start position:0% +the is just the 125 Micron clading all + + + align:start position:0% +the is just the 125 Micron clading all +right so this is then uh the fiber and + + align:start position:0% +right so this is then uh the fiber and + + + align:start position:0% +right so this is then uh the fiber and +there's the output of the of the fiber + + align:start position:0% +there's the output of the of the fiber + + + align:start position:0% +there's the output of the of the fiber +now what we see if we can then enhance + + align:start position:0% +now what we see if we can then enhance + + + align:start position:0% +now what we see if we can then enhance +this and bring it bring it in what we + + align:start position:0% +this and bring it bring it in what we + + + align:start position:0% +this and bring it bring it in what we +see is the uh uh is the single mode uh + + align:start position:0% +see is the uh uh is the single mode uh + + + align:start position:0% +see is the uh uh is the single mode uh +behavior of of a + + align:start position:0% +behavior of of a + + + align:start position:0% +behavior of of a +fiber it looks like almost like a gan + + align:start position:0% +fiber it looks like almost like a gan + + + align:start position:0% +fiber it looks like almost like a gan +kind of uh + + align:start position:0% +kind of uh + + + align:start position:0% +kind of uh +spot not quite gaussian but it looks + + align:start position:0% +spot not quite gaussian but it looks + + + align:start position:0% +spot not quite gaussian but it looks +like a gaussian kind of spot now what + + align:start position:0% +like a gaussian kind of spot now what + + + align:start position:0% +like a gaussian kind of spot now what +I'm doing + + align:start position:0% +I'm doing + + + align:start position:0% +I'm doing +now uh is just it just adjusting the the + + align:start position:0% +now uh is just it just adjusting the the + + + align:start position:0% +now uh is just it just adjusting the the +uh coupling into into the fiber and it's + + align:start position:0% +uh coupling into into the fiber and it's + + + align:start position:0% +uh coupling into into the fiber and it's +very touchy because as I said the core + + align:start position:0% +very touchy because as I said the core + + + align:start position:0% +very touchy because as I said the core +is only about four four + + align:start position:0% +is only about four four + + + align:start position:0% +is only about four four +microns all right so this is what then a + + align:start position:0% +microns all right so this is what then a + + + align:start position:0% +microns all right so this is what then a +single mode uh uh fiber the output from + + align:start position:0% +single mode uh uh fiber the output from + + + align:start position:0% +single mode uh uh fiber the output from +a single mode fiber looks like and if as + + align:start position:0% +a single mode fiber looks like and if as + + + align:start position:0% +a single mode fiber looks like and if as +I miss a line here doesn't make any + + align:start position:0% +I miss a line here doesn't make any + + + align:start position:0% +I miss a line here doesn't make any +difference all you get is just a loss in + + align:start position:0% +difference all you get is just a loss in + + + align:start position:0% +difference all you get is just a loss in +intensity the shape of the mode stays + + align:start position:0% +intensity the shape of the mode stays + + + align:start position:0% +intensity the shape of the mode stays +stays the same so remember the core is + + align:start position:0% +stays the same so remember the core is + + + align:start position:0% +stays the same so remember the core is +four microns cladding is 125 the + + align:start position:0% +four microns cladding is 125 the + + + align:start position:0% +four microns cladding is 125 the +wavelength of the light is 6328 anons + + align:start position:0% +wavelength of the light is 6328 anons + + + align:start position:0% +wavelength of the light is 6328 anons +and the core to index uh difference is + + align:start position:0% +and the core to index uh difference is + + + align:start position:0% +and the core to index uh difference is +about one part in in 10 to the 3 so this + + align:start position:0% +about one part in in 10 to the 3 so this + + + align:start position:0% +about one part in in 10 to the 3 so this +way you can show that indeed you get uh + + align:start position:0% +way you can show that indeed you get uh + + + align:start position:0% +way you can show that indeed you get uh +single mode + + align:start position:0% +single mode + + + align:start position:0% +single mode +propagation now I would like to + + align:start position:0% +propagation now I would like to + + + align:start position:0% +propagation now I would like to +illustrate some interesting phenomena + + align:start position:0% +illustrate some interesting phenomena + + + align:start position:0% +illustrate some interesting phenomena +about fibers so if we get the camera to + + align:start position:0% +about fibers so if we get the camera to + + + align:start position:0% +about fibers so if we get the camera to +look over + + align:start position:0% +look over + + + align:start position:0% +look over +here I want to illustrate how touchy uh + + align:start position:0% +here I want to illustrate how touchy uh + + + align:start position:0% +here I want to illustrate how touchy uh +is the propagation of light in a in a + + align:start position:0% +is the propagation of light in a in a + + + align:start position:0% +is the propagation of light in a in a +single mode fiber now here is here's a + + align:start position:0% +single mode fiber now here is here's a + + + align:start position:0% +single mode fiber now here is here's a +piece of fiber and you can see that + + align:start position:0% +piece of fiber and you can see that + + + align:start position:0% +piece of fiber and you can see that +there's no light scattered from the + + align:start position:0% +there's no light scattered from the + + + align:start position:0% +there's no light scattered from the +fiber now all I have to do is bend the + + align:start position:0% +fiber now all I have to do is bend the + + + align:start position:0% +fiber now all I have to do is bend the +fiber bend the F and you're beginning to + + align:start position:0% +fiber bend the F and you're beginning to + + + align:start position:0% +fiber bend the F and you're beginning to +see light that gets gets transmitted out + + align:start position:0% +see light that gets gets transmitted out + + + align:start position:0% +see light that gets gets transmitted out +of the FI gets essentially kicked out + + align:start position:0% +of the FI gets essentially kicked out + + + align:start position:0% +of the FI gets essentially kicked out +the fiber and uh because because of the + + align:start position:0% +the fiber and uh because because of the + + + align:start position:0% +the fiber and uh because because of the +bend now and and and the reason for that + + align:start position:0% +bend now and and and the reason for that + + + align:start position:0% +bend now and and and the reason for that +because it's you start uh going against + + align:start position:0% +because it's you start uh going against + + + align:start position:0% +because it's you start uh going against +the rules of uh propagation of light in + + align:start position:0% +the rules of uh propagation of light in + + + align:start position:0% +the rules of uh propagation of light in +a + + align:start position:0% +a + + + align:start position:0% +a +fiber for example if you take the ray uh + + align:start position:0% +fiber for example if you take the ray uh + + + align:start position:0% +fiber for example if you take the ray uh +explanation is that what you're doing + + align:start position:0% +explanation is that what you're doing + + + align:start position:0% +explanation is that what you're doing +you are exceeding or or you're changing + + align:start position:0% +you are exceeding or or you're changing + + + align:start position:0% +you are exceeding or or you're changing +the angle of + + align:start position:0% +the angle of + + + align:start position:0% +the angle of +light uh with respect to the to the to + + align:start position:0% +light uh with respect to the to the to + + + align:start position:0% +light uh with respect to the to the to +the uh to the fiber which means that if + + align:start position:0% +the uh to the fiber which means that if + + + align:start position:0% +the uh to the fiber which means that if +you're if you're below the critical + + align:start position:0% +you're if you're below the critical + + + align:start position:0% +you're if you're below the critical +angle then you uh the light is no longer + + align:start position:0% +angle then you uh the light is no longer + + + align:start position:0% +angle then you uh the light is no longer +totally internally reflected and + + align:start position:0% +totally internally reflected and + + + align:start position:0% +totally internally reflected and +therefore gets kicked out + + align:start position:0% +therefore gets kicked out + + + align:start position:0% +therefore gets kicked out +all right so here it is it's very + + align:start position:0% +all right so here it is it's very + + + align:start position:0% +all right so here it is it's very +dramatic as soon as you put Little Bend + + align:start position:0% +dramatic as soon as you put Little Bend + + + align:start position:0% +dramatic as soon as you put Little Bend +in this fiber you can you can kick out a + + align:start position:0% +in this fiber you can you can kick out a + + + align:start position:0% +in this fiber you can you can kick out a +lot of light in fact this the glow uh + + align:start position:0% +lot of light in fact this the glow uh + + + align:start position:0% +lot of light in fact this the glow uh +right here now if we can bring in the + + align:start position:0% +right here now if we can bring in the + + + align:start position:0% +right here now if we can bring in the +the output of the fiber into the inset + + align:start position:0% +the output of the fiber into the inset + + + align:start position:0% +the output of the fiber into the inset +over here now you can see that as I + + align:start position:0% +over here now you can see that as I + + + align:start position:0% +over here now you can see that as I +increase the the band all right you can + + align:start position:0% +increase the the band all right you can + + + align:start position:0% +increase the the band all right you can +see that the intensity yeah I'll do it + + align:start position:0% +see that the intensity yeah I'll do it + + + align:start position:0% +see that the intensity yeah I'll do it +even more intensity then drops quite a + + align:start position:0% +even more intensity then drops quite a + + + align:start position:0% +even more intensity then drops quite a +bit which means I've kicked out almost + + align:start position:0% +bit which means I've kicked out almost + + + align:start position:0% +bit which means I've kicked out almost +all all the light by simply putting a + + align:start position:0% +all all the light by simply putting a + + + align:start position:0% +all all the light by simply putting a +Bend into into the fiber so the the + + align:start position:0% +Bend into into the fiber so the the + + + align:start position:0% +Bend into into the fiber so the the +illustration here then shows that if you + + align:start position:0% +illustration here then shows that if you + + + align:start position:0% +illustration here then shows that if you +leave the fiber alone without sharp + + align:start position:0% +leave the fiber alone without sharp + + + align:start position:0% +leave the fiber alone without sharp +bends everything is fine if you put in a + + align:start position:0% +bends everything is fine if you put in a + + + align:start position:0% +bends everything is fine if you put in a +Bend then you can kick out a lot of + + align:start position:0% +Bend then you can kick out a lot of + + + align:start position:0% +Bend then you can kick out a lot of +light and then not much will be will be + + align:start position:0% +light and then not much will be will be + + + align:start position:0% +light and then not much will be will be +will be + + align:start position:0% +will be + + + align:start position:0% +will be +transmitted so you have to be careful + + align:start position:0% +transmitted so you have to be careful + + + align:start position:0% +transmitted so you have to be careful +you don't put it too tight a Bend + + align:start position:0% +you don't put it too tight a Bend + + + align:start position:0% +you don't put it too tight a Bend +otherwise you Fibber brittle and you + + align:start position:0% +otherwise you Fibber brittle and you + + + align:start position:0% +otherwise you Fibber brittle and you +break the fiber so you have to be be + + align:start position:0% +break the fiber so you have to be be + + + align:start position:0% +break the fiber so you have to be be +careful how you how you do this all + + align:start position:0% +careful how you how you do this all + + + align:start position:0% +careful how you how you do this all +right so in this then in this + + align:start position:0% +right so in this then in this + + + align:start position:0% +right so in this then in this +demonstration we've seen how single mode + + align:start position:0% +demonstration we've seen how single mode + + + align:start position:0% +demonstration we've seen how single mode +fiber behaves in the next demonstration + + align:start position:0% +fiber behaves in the next demonstration + + + align:start position:0% +fiber behaves in the next demonstration +we're going to bring a another fiber + + align:start position:0% +we're going to bring a another fiber + + + align:start position:0% +we're going to bring a another fiber +with a different size core and we're + + align:start position:0% +with a different size core and we're + + + align:start position:0% +with a different size core and we're +going to see what comes out from that + + align:start position:0% + + + + align:start position:0% + +fiber \ No newline at end of file diff --git a/5hETv64GIuE.txt b/5hETv64GIuE.txt new file mode 100644 index 0000000000000000000000000000000000000000..f01d2b113c9cc774a6929731d080041b5b1f0e98 --- /dev/null +++ b/5hETv64GIuE.txt @@ -0,0 +1,2403 @@ +align:start position:0% + +so in this final segment today we're + + align:start position:0% +so in this final segment today we're + + + align:start position:0% +so in this final segment today we're +going to talk about set theory just a + + align:start position:0% +going to talk about set theory just a + + + align:start position:0% +going to talk about set theory just a +little bit + + align:start position:0% +little bit + + + align:start position:0% +little bit +because if you're going to take a math + + align:start position:0% +because if you're going to take a math + + + align:start position:0% +because if you're going to take a math +class if you're going to be exposed to + + align:start position:0% +class if you're going to be exposed to + + + align:start position:0% +class if you're going to be exposed to +math for computer science it's useful to + + align:start position:0% +math for computer science it's useful to + + + align:start position:0% +math for computer science it's useful to +have at least a glimmering of what the + + align:start position:0% +have at least a glimmering of what the + + + align:start position:0% +have at least a glimmering of what the +foundations of math looks like how it + + align:start position:0% +foundations of math looks like how it + + + align:start position:0% +foundations of math looks like how it +starts and how it gets Justified and + + align:start position:0% +starts and how it gets Justified and + + + align:start position:0% +starts and how it gets Justified and +that's what set theory does in addition + + align:start position:0% +that's what set theory does in addition + + + align:start position:0% +that's what set theory does in addition +we will see that um uh the diagonal + + align:start position:0% +we will see that um uh the diagonal + + + align:start position:0% +we will see that um uh the diagonal +argument that we've already made much of + + align:start position:0% +argument that we've already made much of + + + align:start position:0% +argument that we've already made much of +plays a a crucial role in the + + align:start position:0% +plays a a crucial role in the + + + align:start position:0% +plays a a crucial role in the +development and understanding of set + + align:start position:0% +development and understanding of set + + + align:start position:0% +development and understanding of set +theory um so let's begin with an issue + + align:start position:0% +theory um so let's begin with an issue + + + align:start position:0% +theory um so let's begin with an issue +that plays an important role in set + + align:start position:0% +that plays an important role in set + + + align:start position:0% +that plays an important role in set +theory uh and in computer science having + + align:start position:0% +theory uh and in computer science having + + + align:start position:0% +theory uh and in computer science having +to do with the idea of taking a function + + align:start position:0% +to do with the idea of taking a function + + + align:start position:0% +to do with the idea of taking a function +and applying it to itself or or having + + align:start position:0% +and applying it to itself or or having + + + align:start position:0% +and applying it to itself or or having +something refer to itself and this is + + align:start position:0% +something refer to itself and this is + + + align:start position:0% +something refer to itself and this is +one of these things that's notoriously + + align:start position:0% +one of these things that's notoriously + + + align:start position:0% +one of these things that's notoriously +doubtful there's all these paradoxes + + align:start position:0% +doubtful there's all these paradoxes + + + align:start position:0% +doubtful there's all these paradoxes +about it maybe the simplest one is when + + align:start position:0% +about it maybe the simplest one is when + + + align:start position:0% +about it maybe the simplest one is when +I uh assert this statement is false and + + align:start position:0% +I uh assert this statement is false and + + + align:start position:0% +I uh assert this statement is false and +the question is is it true or false well + + align:start position:0% +the question is is it true or false well + + + align:start position:0% +the question is is it true or false well +if it's true then it's false and if it's + + align:start position:0% +if it's true then it's false and if it's + + + align:start position:0% +if it's true then it's false and if it's +false then it's true and we get a kind + + align:start position:0% +false then it's true and we get a kind + + + align:start position:0% +false then it's true and we get a kind +of buzzer uh it's not possible to figure + + align:start position:0% +of buzzer uh it's not possible to figure + + + align:start position:0% +of buzzer uh it's not possible to figure +out whether this statement is true or + + align:start position:0% +out whether this statement is true or + + + align:start position:0% +out whether this statement is true or +false I think we would deny that it was + + align:start position:0% +false I think we would deny that it was + + + align:start position:0% +false I think we would deny that it was +a proposition so that's a hint that + + align:start position:0% +a proposition so that's a hint that + + + align:start position:0% +a proposition so that's a hint that +there's something suspicious about + + align:start position:0% +there's something suspicious about + + + align:start position:0% +there's something suspicious about +self-reference and self-application and + + align:start position:0% +self-reference and self-application and + + + align:start position:0% +self-reference and self-application and +so on on the other hand it's worth + + align:start position:0% +so on on the other hand it's worth + + + align:start position:0% +so on on the other hand it's worth +remembering that in computer science we + + align:start position:0% +remembering that in computer science we + + + align:start position:0% +remembering that in computer science we +take this for granted so let's look at + + align:start position:0% +take this for granted so let's look at + + + align:start position:0% +take this for granted so let's look at +an example um here's a simple example of + + align:start position:0% +an example um here's a simple example of + + + align:start position:0% +an example um here's a simple example of +a list in uh scheme lisp notation um + + align:start position:0% +a list in uh scheme lisp notation um + + + align:start position:0% +a list in uh scheme lisp notation um +meaning it's a list of three things 0o + + align:start position:0% +meaning it's a list of three things 0o + + + align:start position:0% +meaning it's a list of three things 0o +one and two uh and the the black Parn + + align:start position:0% +one and two uh and the the black Parn + + + align:start position:0% +one and two uh and the the black Parn +indicate that we're thinking of it as an + + align:start position:0% +indicate that we're thinking of it as an + + + align:start position:0% +indicate that we're thinking of it as an +ordered list now the way that I would + + align:start position:0% +ordered list now the way that I would + + + align:start position:0% +ordered list now the way that I would +represent a list like that in memory + + align:start position:0% +represent a list like that in memory + + + align:start position:0% +represent a list like that in memory +typically is by using these things that + + align:start position:0% +typically is by using these things that + + + align:start position:0% +typically is by using these things that +are called conell so a conell has these + + align:start position:0% +are called conell so a conell has these + + + align:start position:0% +are called conell so a conell has these +two parts the leftand part points to the + + align:start position:0% +two parts the leftand part points to the + + + align:start position:0% +two parts the leftand part points to the +uh value in that location in the list so + + align:start position:0% +uh value in that location in the list so + + + align:start position:0% +uh value in that location in the list so +this first conell points to zero which + + align:start position:0% +this first conell points to zero which + + + align:start position:0% +this first conell points to zero which +is the first element of the list the + + align:start position:0% +is the first element of the list the + + + align:start position:0% +is the first element of the list the +second component of the conell points to + + align:start position:0% +second component of the conell points to + + + align:start position:0% +second component of the conell points to +the next element of the list and so here + + align:start position:0% +the next element of the list and so here + + + align:start position:0% +the next element of the list and so here +you see one pointing to the third + + align:start position:0% +you see one pointing to the third + + + align:start position:0% +you see one pointing to the third +element of the list and there you see + + align:start position:0% +element of the list and there you see + + + align:start position:0% +element of the list and there you see +two and that little uh nil marker + + align:start position:0% +two and that little uh nil marker + + + align:start position:0% +two and that little uh nil marker +indicates that's the end of the list so + + align:start position:0% +indicates that's the end of the list so + + + align:start position:0% +indicates that's the end of the list so +that's a simple representation of a list + + align:start position:0% +that's a simple representation of a list + + + align:start position:0% +that's a simple representation of a list +of length three with three conell well + + align:start position:0% +of length three with three conell well + + + align:start position:0% +of length three with three conell well +one of the things that um a computer + + align:start position:0% +one of the things that um a computer + + + align:start position:0% +one of the things that um a computer +science lets you do and many languages + + align:start position:0% +science lets you do and many languages + + + align:start position:0% +science lets you do and many languages +let you do is that you can manipulate + + align:start position:0% +let you do is that you can manipulate + + + align:start position:0% +let you do is that you can manipulate +these pointers so using uh the language + + align:start position:0% +these pointers so using uh the language + + + align:start position:0% +these pointers so using uh the language +of scheme what I can do is uh do an + + align:start position:0% +of scheme what I can do is uh do an + + + align:start position:0% +of scheme what I can do is uh do an +operation called set car where I'm + + align:start position:0% +operation called set car where I'm + + + align:start position:0% +operation called set car where I'm +taking in this case I'm setting the + + align:start position:0% +taking in this case I'm setting the + + + align:start position:0% +taking in this case I'm setting the +second element of L that is this conel + + align:start position:0% +second element of L that is this conel + + + align:start position:0% +second element of L that is this conel +to L and set car is saying let's change + + align:start position:0% +to L and set car is saying let's change + + + align:start position:0% +to L and set car is saying let's change +what the element in the uh uh uh in the + + align:start position:0% +what the element in the uh uh uh in the + + + align:start position:0% +what the element in the uh uh uh in the +left hand part of this uh cell is this + + align:start position:0% +left hand part of this uh cell is this + + + align:start position:0% +left hand part of this uh cell is this +is where the value of the second element + + align:start position:0% +is where the value of the second element + + + align:start position:0% +is where the value of the second element +is let's change the value of the second + + align:start position:0% +is let's change the value of the second + + + align:start position:0% +is let's change the value of the second +element to BL l what does that mean as a + + align:start position:0% +element to BL l what does that mean as a + + + align:start position:0% +element to BL l what does that mean as a +pointer manipulation well it's pretty + + align:start position:0% +pointer manipulation well it's pretty + + + align:start position:0% +pointer manipulation well it's pretty +simple I just move this pointer to point + + align:start position:0% +simple I just move this pointer to point + + + align:start position:0% +simple I just move this pointer to point +to the beginning of the list L and now I + + align:start position:0% +to the beginning of the list L and now I + + + align:start position:0% +to the beginning of the list L and now I +have an interesting situation because + + align:start position:0% +have an interesting situation because + + + align:start position:0% +have an interesting situation because +this list uh now is a list that consists + + align:start position:0% +this list uh now is a list that consists + + + align:start position:0% +this list uh now is a list that consists +of of uh zero and L and two it's a list + + align:start position:0% +of of uh zero and L and two it's a list + + + align:start position:0% +of of uh zero and L and two it's a list +that has itself as a member and it makes + + align:start position:0% +that has itself as a member and it makes + + + align:start position:0% +that has itself as a member and it makes +perfect sense um uh and if you sort of + + align:start position:0% +perfect sense um uh and if you sort of + + + align:start position:0% +perfect sense um uh and if you sort of +expand it out L is this list that has + + align:start position:0% +expand it out L is this list that has + + + align:start position:0% +expand it out L is this list that has +begins with zero and then its second + + align:start position:0% +begins with zero and then its second + + + align:start position:0% +begins with zero and then its second +element is a list that begins with zero + + align:start position:0% +element is a list that begins with zero + + + align:start position:0% +element is a list that begins with zero +um and the second element of that list + + align:start position:0% +um and the second element of that list + + + align:start position:0% +um and the second element of that list +is a list that begins with zero and so + + align:start position:0% +is a list that begins with zero and so + + + align:start position:0% +is a list that begins with zero and so +on and then uh the third element of L is + + align:start position:0% +on and then uh the third element of L is + + + align:start position:0% +on and then uh the third element of L is +two and the third element of the second + + align:start position:0% +two and the third element of the second + + + align:start position:0% +two and the third element of the second +element of L is two and so on it's an + + align:start position:0% +element of L is two and so on it's an + + + align:start position:0% +element of L is two and so on it's an +interesting infinite nested structure + + align:start position:0% +interesting infinite nested structure + + + align:start position:0% +interesting infinite nested structure +that's nicely represented by this finite + + align:start position:0% +that's nicely represented by this finite + + + align:start position:0% +that's nicely represented by this finite +um uh circular + + align:start position:0% +um uh circular + + + align:start position:0% +um uh circular +list okay um let's look at another + + align:start position:0% +list okay um let's look at another + + + align:start position:0% +list okay um let's look at another +example Le where in computer science we + + align:start position:0% +example Le where in computer science we + + + align:start position:0% +example Le where in computer science we +actually apply things to themselves so + + align:start position:0% +actually apply things to themselves so + + + align:start position:0% +actually apply things to themselves so +let's define the composition operator + + align:start position:0% +let's define the composition operator + + + align:start position:0% +let's define the composition operator +and again I'm using uh notation from the + + align:start position:0% +and again I'm using uh notation from the + + + align:start position:0% +and again I'm using uh notation from the +language scheme I want to take two + + align:start position:0% +language scheme I want to take two + + + align:start position:0% +language scheme I want to take two +functions f and g that take one argument + + align:start position:0% +functions f and g that take one argument + + + align:start position:0% +functions f and g that take one argument +and I'm going to Define their + + align:start position:0% +and I'm going to Define their + + + align:start position:0% +and I'm going to Define their +composition the way that I compose f and + + align:start position:0% +composition the way that I compose f and + + + align:start position:0% +composition the way that I compose f and +g is I Define a new function H ofx which + + align:start position:0% +g is I Define a new function H ofx which + + + align:start position:0% +g is I Define a new function H ofx which +is going to be the composition of H and + + align:start position:0% +is going to be the composition of H and + + + align:start position:0% +is going to be the composition of H and +G the way I Define h of X is I say apply + + align:start position:0% +G the way I Define h of X is I say apply + + + align:start position:0% +G the way I Define h of X is I say apply +G to F to G apply F to G apply to X and + + align:start position:0% +G to F to G apply F to G apply to X and + + + align:start position:0% +G to F to G apply F to G apply to X and +return the value H so this is a a + + align:start position:0% +return the value H so this is a a + + + align:start position:0% +return the value H so this is a a +compose is a procedure that takes two + + align:start position:0% +compose is a procedure that takes two + + + align:start position:0% +compose is a procedure that takes two +procedures f and g and returns their + + align:start position:0% +procedures f and g and returns their + + + align:start position:0% +procedures f and g and returns their +composition + + align:start position:0% +composition + + + align:start position:0% +composition +H okay let's practice suppose that I + + align:start position:0% +H okay let's practice suppose that I + + + align:start position:0% +H okay let's practice suppose that I +compose the square function that Maps X + + align:start position:0% +compose the square function that Maps X + + + align:start position:0% +compose the square function that Maps X +to x^2 and the add one function that + + align:start position:0% +to x^2 and the add one function that + + + align:start position:0% +to x^2 and the add one function that +Maps X to x + 1 well um if I uh compose + + align:start position:0% +Maps X to x + 1 well um if I uh compose + + + align:start position:0% +Maps X to x + 1 well um if I uh compose +the square of adding one and I it to + + align:start position:0% +the square of adding one and I it to + + + align:start position:0% +the square of adding one and I it to +three what I'm saying is uh let's add + + align:start position:0% +three what I'm saying is uh let's add + + + align:start position:0% +three what I'm saying is uh let's add +one to three and then Square it and I + + align:start position:0% +one to three and then Square it and I + + + align:start position:0% +one to three and then Square it and I +get 3 + 1^ squ or 16 cuz the add one and + + align:start position:0% +get 3 + 1^ squ or 16 cuz the add one and + + + align:start position:0% +get 3 + 1^ squ or 16 cuz the add one and +then Square it is the function that's + + align:start position:0% +then Square it is the function that's + + + align:start position:0% +then Square it is the function that's +the composition of square and add one + + align:start position:0% +the composition of square and add one + + + align:start position:0% +the composition of square and add one +now I can do the following I could + + align:start position:0% +now I can do the following I could + + + align:start position:0% +now I can do the following I could +Square I could compose square with + + align:start position:0% +Square I could compose square with + + + align:start position:0% +Square I could compose square with +itself if I take the function Square it + + align:start position:0% +itself if I take the function Square it + + + align:start position:0% +itself if I take the function Square it +and square that I'm really taking the + + align:start position:0% +and square that I'm really taking the + + + align:start position:0% +and square that I'm really taking the +fourth power so if I apply the function + + align:start position:0% +fourth power so if I apply the function + + + align:start position:0% +fourth power so if I apply the function +composed of square squ to 3 I get 3^ s^ + + align:start position:0% +composed of square squ to 3 I get 3^ s^ + + + align:start position:0% +composed of square squ to 3 I get 3^ s^ +S or 81 or 3 4 all makes perfect sense + + align:start position:0% +S or 81 or 3 4 all makes perfect sense + + + align:start position:0% +S or 81 or 3 4 all makes perfect sense +okay well now let's uh Define a a + + align:start position:0% +okay well now let's uh Define a a + + + align:start position:0% +okay well now let's uh Define a a +composite with itself operation I'm + + align:start position:0% +composite with itself operation I'm + + + align:start position:0% +composite with itself operation I'm +going to call it comp 2 comp 2 takes one + + align:start position:0% +going to call it comp 2 comp 2 takes one + + + align:start position:0% +going to call it comp 2 comp 2 takes one +function f and the definition of comp 2 + + align:start position:0% +function f and the definition of comp 2 + + + align:start position:0% +function f and the definition of comp 2 +is compose f with + + align:start position:0% +is compose f with + + + align:start position:0% +is compose f with +f um and if I uh then apply comp 2 to + + align:start position:0% +f um and if I uh then apply comp 2 to + + + align:start position:0% +f um and if I uh then apply comp 2 to +square and three it's saying okay okay + + align:start position:0% +square and three it's saying okay okay + + + align:start position:0% +square and three it's saying okay okay +compose square and square we just did + + align:start position:0% +compose square and square we just did + + + align:start position:0% +compose square and square we just did +that that was the fourth power apply it + + align:start position:0% +that that was the fourth power apply it + + + align:start position:0% +that that was the fourth power apply it +to three I get + + align:start position:0% +to three I get + + + align:start position:0% +to three I get +81 and now we can do some weird stuff + + align:start position:0% +81 and now we can do some weird stuff + + + align:start position:0% +81 and now we can do some weird stuff +because suppose that I apply comp 2 to + + align:start position:0% +because suppose that I apply comp 2 to + + + align:start position:0% +because suppose that I apply comp 2 to +comp two and then apply that to add one + + align:start position:0% +comp two and then apply that to add one + + + align:start position:0% +comp two and then apply that to add one +and apply that to + + align:start position:0% +and apply that to + + + align:start position:0% +and apply that to +three well that one's a little hard to + + align:start position:0% +three well that one's a little hard to + + + align:start position:0% +three well that one's a little hard to +follow and I'm going to let you think it + + align:start position:0% +follow and I'm going to let you think it + + + align:start position:0% +follow and I'm going to let you think it +through but comp two of comp two is + + align:start position:0% +through but comp two of comp two is + + + align:start position:0% +through but comp two of comp two is +compose something with it four times and + + align:start position:0% +compose something with it four times and + + + align:start position:0% +compose something with it four times and +when you do that with add one what + + align:start position:0% +when you do that with add one what + + + align:start position:0% +when you do that with add one what +happens is that uh you're uh adding one + + align:start position:0% +happens is that uh you're uh adding one + + + align:start position:0% +happens is that uh you're uh adding one +four times to three if I comp two of + + align:start position:0% +four times to three if I comp two of + + + align:start position:0% +four times to three if I comp two of +comp two of square I'm uh composing + + align:start position:0% +comp two of square I'm uh composing + + + align:start position:0% +comp two of square I'm uh composing +square with itself and then composing + + align:start position:0% +square with itself and then composing + + + align:start position:0% +square with itself and then composing +that with itself I'm really squaring + + align:start position:0% +that with itself I'm really squaring + + + align:start position:0% +that with itself I'm really squaring +four times um and I wind up with uh 2 to + + align:start position:0% +four times um and I wind up with uh 2 to + + + align:start position:0% +four times um and I wind up with uh 2 to +the 4th or + + align:start position:0% +the 4th or + + + align:start position:0% +the 4th or +16 uh uh is the power that I'm taking + + align:start position:0% +16 uh uh is the power that I'm taking + + + align:start position:0% +16 uh uh is the power that I'm taking +and so composed to of composed to of + + align:start position:0% +and so composed to of composed to of + + + align:start position:0% +and so composed to of composed to of +square of three is this rather large + + align:start position:0% +square of three is this rather large + + + align:start position:0% +square of three is this rather large +number 3 to the 16th it could be a + + align:start position:0% +number 3 to the 16th it could be a + + + align:start position:0% +number 3 to the 16th it could be a +little bit tricky to think through but + + align:start position:0% +little bit tricky to think through but + + + align:start position:0% +little bit tricky to think through but +it all makes perfect sense and it works + + align:start position:0% +it all makes perfect sense and it works + + + align:start position:0% +it all makes perfect sense and it works +just fine in recursive programming + + align:start position:0% +just fine in recursive programming + + + align:start position:0% +just fine in recursive programming +languages that allow this kind of + + align:start position:0% +languages that allow this kind of + + + align:start position:0% +languages that allow this kind of +untyped uh or generically typed + + align:start position:0% +untyped uh or generically typed + + + align:start position:0% +untyped uh or generically typed +composition okay so why is it that + + align:start position:0% +composition okay so why is it that + + + align:start position:0% +composition okay so why is it that +computer scientists are so daring and + + align:start position:0% +computer scientists are so daring and + + + align:start position:0% +computer scientists are so daring and +mathematicians are so timid about + + align:start position:0% +mathematicians are so timid about + + + align:start position:0% +mathematicians are so timid about +self-reference and the reason is the + + align:start position:0% +self-reference and the reason is the + + + align:start position:0% +self-reference and the reason is the +mathematicians have been traumatized by + + align:start position:0% +mathematicians have been traumatized by + + + align:start position:0% +mathematicians have been traumatized by +ber Russell because of Russell's famous + + align:start position:0% +ber Russell because of Russell's famous + + + align:start position:0% +ber Russell because of Russell's famous +Paradox which we're now ready to look at + + align:start position:0% +Paradox which we're now ready to look at + + + align:start position:0% +Paradox which we're now ready to look at +so um what Russell was proposing uh and + + align:start position:0% +so um what Russell was proposing uh and + + + align:start position:0% +so um what Russell was proposing uh and +it's going to look just like a diagonal + + align:start position:0% +it's going to look just like a diagonal + + + align:start position:0% +it's going to look just like a diagonal +argument is Russell said let's let W be + + align:start position:0% +argument is Russell said let's let W be + + + align:start position:0% +argument is Russell said let's let W be +the collection of + + align:start position:0% +the collection of + + + align:start position:0% +the collection of +sets uh s such that s is not a member of + + align:start position:0% +sets uh s such that s is not a member of + + + align:start position:0% +sets uh s such that s is not a member of +s now let's think about that for a + + align:start position:0% +s now let's think about that for a + + + align:start position:0% +s now let's think about that for a +little bit most sets are not members of + + align:start position:0% +little bit most sets are not members of + + + align:start position:0% +little bit most sets are not members of +themselves like um the set of integers + + align:start position:0% +themselves like um the set of integers + + + align:start position:0% +themselves like um the set of integers +uh is not a member of itself because the + + align:start position:0% +uh is not a member of itself because the + + + align:start position:0% +uh is not a member of itself because the +only thing in it is in it are integers + + align:start position:0% +only thing in it is in it are integers + + + align:start position:0% +only thing in it is in it are integers +um and the set of the power set of the + + align:start position:0% +um and the set of the power set of the + + + align:start position:0% +um and the set of the power set of the +integers is not a member of itself + + align:start position:0% +integers is not a member of itself + + + align:start position:0% +integers is not a member of itself +because every uh member of the power set + + align:start position:0% +because every uh member of the power set + + + align:start position:0% +because every uh member of the power set +of integers is a set of integers whereas + + align:start position:0% +of integers is a set of integers whereas + + + align:start position:0% +of integers is a set of integers whereas +the power set of integers is a set of + + align:start position:0% +the power set of integers is a set of + + + align:start position:0% +the power set of integers is a set of +sets of those things so those familiar + + align:start position:0% +sets of those things so those familiar + + + align:start position:0% +sets of those things so those familiar +sets are typically not members of + + align:start position:0% +sets are typically not members of + + + align:start position:0% +sets are typically not members of +themselves but who knows maybe there are + + align:start position:0% +themselves but who knows maybe there are + + + align:start position:0% +themselves but who knows maybe there are +these weird sets like the uh uh like the + + align:start position:0% +these weird sets like the uh uh like the + + + align:start position:0% +these weird sets like the uh uh like the +circular list or a function that can + + align:start position:0% +circular list or a function that can + + + align:start position:0% +circular list or a function that can +compose with itself that is a member of + + align:start position:0% +compose with itself that is a member of + + + align:start position:0% +compose with itself that is a member of +itself now let me step back for a moment + + align:start position:0% +itself now let me step back for a moment + + + align:start position:0% +itself now let me step back for a moment +and and mention where where did Russell + + align:start position:0% +and and mention where where did Russell + + + align:start position:0% +and and mention where where did Russell +get thinking about this and it it comes + + align:start position:0% +get thinking about this and it it comes + + + align:start position:0% +get thinking about this and it it comes +from the period in the late 19th century + + align:start position:0% +from the period in the late 19th century + + + align:start position:0% +from the period in the late 19th century +when mathematicians and logicians were + + align:start position:0% +when mathematicians and logicians were + + + align:start position:0% +when mathematicians and logicians were +trying to think about uh uh confirming + + align:start position:0% +trying to think about uh uh confirming + + + align:start position:0% +trying to think about uh uh confirming +and establishing the foundations of math + + align:start position:0% +and establishing the foundations of math + + + align:start position:0% +and establishing the foundations of math +what was math absolutely about what were + + align:start position:0% +what was math absolutely about what were + + + align:start position:0% +what was math absolutely about what were +the fundamental objects that uh that + + align:start position:0% +the fundamental objects that uh that + + + align:start position:0% +the fundamental objects that uh that +mathematics could be built from and what + + align:start position:0% +mathematics could be built from and what + + + align:start position:0% +mathematics could be built from and what +would with the rules for understanding + + align:start position:0% +would with the rules for understanding + + + align:start position:0% +would with the rules for understanding +those OB objects and it was pretty well + + align:start position:0% +those OB objects and it was pretty well + + + align:start position:0% +those OB objects and it was pretty well +agreed that sets were it you could build + + align:start position:0% +agreed that sets were it you could build + + + align:start position:0% +agreed that sets were it you could build +everything out of sets and you just need + + align:start position:0% +everything out of sets and you just need + + + align:start position:0% +everything out of sets and you just need +to understand sets and then you were in + + align:start position:0% +to understand sets and then you were in + + + align:start position:0% +to understand sets and then you were in +business uh and there was a German + + align:start position:0% +business uh and there was a German + + + align:start position:0% +business uh and there was a German +mathematician named Fraga uh who tried + + align:start position:0% +mathematician named Fraga uh who tried + + + align:start position:0% +mathematician named Fraga uh who tried +to demonstrate this by developing uh a + + align:start position:0% +to demonstrate this by developing uh a + + + align:start position:0% +to demonstrate this by developing uh a +set theory very carefully giving careful + + align:start position:0% +set theory very carefully giving careful + + + align:start position:0% +set theory very carefully giving careful +axioms for what sets were and he showed + + align:start position:0% +axioms for what sets were and he showed + + + align:start position:0% +axioms for what sets were and he showed +how you could build out of sets you + + align:start position:0% +how you could build out of sets you + + + align:start position:0% +how you could build out of sets you +could build the integers and then you + + align:start position:0% +could build the integers and then you + + + align:start position:0% +could build the integers and then you +could build rationals which are sort of + + align:start position:0% +could build rationals which are sort of + + + align:start position:0% +could build rationals which are sort of +just pairs of integers and then you + + align:start position:0% +just pairs of integers and then you + + + align:start position:0% +just pairs of integers and then you +could build real numbers by taking + + align:start position:0% +could build real numbers by taking + + + align:start position:0% +could build real numbers by taking +collections of rationals that um uh that + + align:start position:0% +collections of rationals that um uh that + + + align:start position:0% +collections of rationals that um uh that +had at least upper bound and uh and then + + align:start position:0% +had at least upper bound and uh and then + + + align:start position:0% +had at least upper bound and uh and then +you can keep going you can build + + align:start position:0% +you can keep going you can build + + + align:start position:0% +you can keep going you can build +functions and continuous functions and + + align:start position:0% +functions and continuous functions and + + + align:start position:0% +functions and continuous functions and +he showed how you could build up um the + + align:start position:0% +he showed how you could build up um the + + + align:start position:0% +he showed how you could build up um the +basic structures of mathematical + + align:start position:0% +basic structures of mathematical + + + align:start position:0% +basic structures of mathematical +analysis and prove their basic theorems + + align:start position:0% +analysis and prove their basic theorems + + + align:start position:0% +analysis and prove their basic theorems +in his formal set theory the problem was + + align:start position:0% +in his formal set theory the problem was + + + align:start position:0% +in his formal set theory the problem was +that Russell came along and looked at + + align:start position:0% +that Russell came along and looked at + + + align:start position:0% +that Russell came along and looked at +fragga set theory and came up with the + + align:start position:0% +fragga set theory and came up with the + + + align:start position:0% +fragga set theory and came up with the +following + + align:start position:0% +following + + + align:start position:0% +following +Paradox he defined W to be the + + align:start position:0% +Paradox he defined W to be the + + + align:start position:0% +Paradox he defined W to be the +collection of s and sets such that s is + + align:start position:0% +collection of s and sets such that s is + + + align:start position:0% +collection of s and sets such that s is +not a member of s fro would certainly + + align:start position:0% +not a member of s fro would certainly + + + align:start position:0% +not a member of s fro would certainly +have said that's a well-defined set and + + align:start position:0% +have said that's a well-defined set and + + + align:start position:0% +have said that's a well-defined set and +and he will acknowledge that W is a set + + align:start position:0% +and he will acknowledge that W is a set + + + align:start position:0% +and he will acknowledge that W is a set +um and let's look at what this means and + + align:start position:0% +um and let's look at what this means and + + + align:start position:0% +um and let's look at what this means and +I mean this is diagonal argument so + + align:start position:0% +I mean this is diagonal argument so + + + align:start position:0% +I mean this is diagonal argument so +let's remember what's the by this + + align:start position:0% +let's remember what's the by this + + + align:start position:0% +let's remember what's the by this +definition of w what we have is that a + + align:start position:0% +definition of w what we have is that a + + + align:start position:0% +definition of w what we have is that a +set s is in W if and only if s is not a + + align:start position:0% +set s is in W if and only if s is not a + + + align:start position:0% +set s is in W if and only if s is not a +member of s okay that's fine then just + + align:start position:0% +member of s okay that's fine then just + + + align:start position:0% +member of s okay that's fine then just +let s be W and we immediately get a + + align:start position:0% +let s be W and we immediately get a + + + align:start position:0% +let s be W and we immediately get a +contradiction that W is in W if and only + + align:start position:0% +contradiction that W is in W if and only + + + align:start position:0% +contradiction that W is in W if and only +if W is not in W poor + + align:start position:0% +if W is not in W poor + + + align:start position:0% +if W is not in W poor +frager his book was a disaster math is + + align:start position:0% +frager his book was a disaster math is + + + align:start position:0% +frager his book was a disaster math is +broken um uh uh you can prove that + + align:start position:0% +broken um uh uh you can prove that + + + align:start position:0% +broken um uh uh you can prove that +you're the pope you can prove the pigs + + align:start position:0% +you're the pope you can prove the pigs + + + align:start position:0% +you're the pope you can prove the pigs +fly verified programs crash math is just + + align:start position:0% +fly verified programs crash math is just + + + align:start position:0% +fly verified programs crash math is just +broken um it's not reliable you can + + align:start position:0% +broken um it's not reliable you can + + + align:start position:0% +broken um it's not reliable you can +prove anything by in frga system because + + align:start position:0% +prove anything by in frga system because + + + align:start position:0% +prove anything by in frga system because +it reached a contradiction and from + + align:start position:0% +it reached a contradiction and from + + + align:start position:0% +it reached a contradiction and from +something false you can prove anything + + align:start position:0% +something false you can prove anything + + + align:start position:0% +something false you can prove anything +well frga + + align:start position:0% +well frga + + + align:start position:0% +well frga +you know had a book it was a vanity + + align:start position:0% +you know had a book it was a vanity + + + align:start position:0% +you know had a book it was a vanity +publication uh and the the preface of it + + align:start position:0% +publication uh and the the preface of it + + + align:start position:0% +publication uh and the the preface of it +had to be Rewritten and he said look um + + align:start position:0% +had to be Rewritten and he said look um + + + align:start position:0% +had to be Rewritten and he said look um +uh my system's broken and I know that + + align:start position:0% +uh my system's broken and I know that + + + align:start position:0% +uh my system's broken and I know that +and Russell showed that unambiguously + + align:start position:0% +and Russell showed that unambiguously + + + align:start position:0% +and Russell showed that unambiguously +but I think that there's still something + + align:start position:0% +but I think that there's still something + + + align:start position:0% +but I think that there's still something +here that's salvageable and so I'm going + + align:start position:0% +here that's salvageable and so I'm going + + + align:start position:0% +here that's salvageable and so I'm going +to publish the book but I apologize for + + align:start position:0% +to publish the book but I apologize for + + + align:start position:0% +to publish the book but I apologize for +the fact that you can't rely on the + + align:start position:0% +the fact that you can't rely on the + + + align:start position:0% +the fact that you can't rely on the +conclusions um poor frago uh that was + + align:start position:0% +conclusions um poor frago uh that was + + + align:start position:0% +conclusions um poor frago uh that was +his life work gone down the + + align:start position:0% +his life work gone down the + + + align:start position:0% +his life work gone down the +drain okay + + align:start position:0% +drain okay + + + align:start position:0% +drain okay +um how do we resolve this what's wrong + + align:start position:0% +um how do we resolve this what's wrong + + + align:start position:0% +um how do we resolve this what's wrong +with this apparent Paradox of Russell's + + align:start position:0% +with this apparent Paradox of Russell's + + + align:start position:0% +with this apparent Paradox of Russell's +well um the Assumption was that W was a + + align:start position:0% +well um the Assumption was that W was a + + + align:start position:0% +well um the Assumption was that W was a +set and that turns out to be what we can + + align:start position:0% +set and that turns out to be what we can + + + align:start position:0% +set and that turns out to be what we can +doubt so the definition of w is that for + + align:start position:0% +doubt so the definition of w is that for + + + align:start position:0% +doubt so the definition of w is that for +all sets w s is in W if and only if s is + + align:start position:0% +all sets w s is in W if and only if s is + + + align:start position:0% +all sets w s is in W if and only if s is +not in s and we got a contradiction by + + align:start position:0% +not in s and we got a contradiction by + + + align:start position:0% +not in s and we got a contradiction by +saying okay um substitute W for S but + + align:start position:0% +saying okay um substitute W for S but + + + align:start position:0% +saying okay um substitute W for S but +that's allowed only if you believe that + + align:start position:0% +that's allowed only if you believe that + + + align:start position:0% +that's allowed only if you believe that +W is a set now it looks like it ought to + + align:start position:0% +W is a set now it looks like it ought to + + + align:start position:0% +W is a set now it looks like it ought to +be because it's certainly well defined + + align:start position:0% +be because it's certainly well defined + + + align:start position:0% +be because it's certainly well defined +by that + + align:start position:0% +by that + + + align:start position:0% +by that +formula uh but it was well understood at + + align:start position:0% +formula uh but it was well understood at + + + align:start position:0% +formula uh but it was well understood at +the time that that was the fix to the + + align:start position:0% +the time that that was the fix to the + + + align:start position:0% +the time that that was the fix to the +Paradox you just can't allow W to be a + + align:start position:0% +Paradox you just can't allow W to be a + + + align:start position:0% +Paradox you just can't allow W to be a +set um the problem was that W was + + align:start position:0% +set um the problem was that W was + + + align:start position:0% +set um the problem was that W was +acknowledged by everybody to be + + align:start position:0% +acknowledged by everybody to be + + + align:start position:0% +acknowledged by everybody to be +absolutely clearly defined + + align:start position:0% +absolutely clearly defined + + + align:start position:0% +absolutely clearly defined +mathematically it was this bunch of sets + + align:start position:0% +mathematically it was this bunch of sets + + + align:start position:0% +mathematically it was this bunch of sets +and yet we're going to say it's not a + + align:start position:0% +and yet we're going to say it's not a + + + align:start position:0% +and yet we're going to say it's not a +set well it's okay that will fix + + align:start position:0% +set well it's okay that will fix + + + align:start position:0% +set well it's okay that will fix +Russell's Paradox but it leaves us with + + align:start position:0% +Russell's Paradox but it leaves us with + + + align:start position:0% +Russell's Paradox but it leaves us with +a much bigger General philosophical + + align:start position:0% +a much bigger General philosophical + + + align:start position:0% +a much bigger General philosophical +question is when is a well-defined + + align:start position:0% +question is when is a well-defined + + + align:start position:0% +question is when is a well-defined +mathematical object a set and when isn't + + align:start position:0% +mathematical object a set and when isn't + + + align:start position:0% +mathematical object a set and when isn't +a set and that's what you need + + align:start position:0% +a set and that's what you need + + + align:start position:0% +a set and that's what you need +sophisticated rules for when is it that + + align:start position:0% +sophisticated rules for when is it that + + + align:start position:0% +sophisticated rules for when is it that +you're going to Define some collection + + align:start position:0% +you're going to Define some collection + + + align:start position:0% +you're going to Define some collection +of elements and you can be sure it's a + + align:start position:0% +of elements and you can be sure it's a + + + align:start position:0% +of elements and you can be sure it's a +set as opposed to something else called + + align:start position:0% +set as opposed to something else called + + + align:start position:0% +set as opposed to something else called +a class by the way uh which is uh + + align:start position:0% +a class by the way uh which is uh + + + align:start position:0% +a class by the way uh which is uh +basically something that's too big to be + + align:start position:0% +basically something that's too big to be + + + align:start position:0% +basically something that's too big to be +a set because if it was a set it would + + align:start position:0% +a set because if it was a set it would + + + align:start position:0% +a set because if it was a set it would +be uh it would contain itself and be + + align:start position:0% +be uh it would contain itself and be + + + align:start position:0% +be uh it would contain itself and be +circular and + + align:start position:0% +circular and + + + align:start position:0% +circular and +self-referential well there's no simple + + align:start position:0% +self-referential well there's no simple + + + align:start position:0% +self-referential well there's no simple +answer to this question about what + + align:start position:0% +answer to this question about what + + + align:start position:0% +answer to this question about what +things are sets and what are not sets + + align:start position:0% +things are sets and what are not sets + + + align:start position:0% +things are sets and what are not sets +but over uh time by the 1930s people had + + align:start position:0% +but over uh time by the 1930s people had + + + align:start position:0% +but over uh time by the 1930s people had +pretty much settled on an very + + align:start position:0% +pretty much settled on an very + + + align:start position:0% +pretty much settled on an very +economical and and persuasive set of + + align:start position:0% +economical and and persuasive set of + + + align:start position:0% +economical and and persuasive set of +axioms for set theory called the zuro + + align:start position:0% +axioms for set theory called the zuro + + + align:start position:0% +axioms for set theory called the zuro +Frankle set theory axioms \ No newline at end of file diff --git a/6b9AW6QxXt0.txt b/6b9AW6QxXt0.txt new file mode 100644 index 0000000000000000000000000000000000000000..61cdb38050934850a3a4569391407f7a16e6ef2c --- /dev/null +++ b/6b9AW6QxXt0.txt @@ -0,0 +1,2371 @@ +align:start position:0% + +okay uh this video is about one of the + + align:start position:0% +okay uh this video is about one of the + + + align:start position:0% +okay uh this video is about one of the +key applications of ordinary + + align:start position:0% +key applications of ordinary + + + align:start position:0% +key applications of ordinary +differential equations to electrical + + align:start position:0% +differential equations to electrical + + + align:start position:0% +differential equations to electrical +flow flow of currents in a in a network + + align:start position:0% +flow flow of currents in a in a network + + + align:start position:0% +flow flow of currents in a in a network +and so I drew a network a very simple + + align:start position:0% +and so I drew a network a very simple + + + align:start position:0% +and so I drew a network a very simple +Network it's just called an + + align:start position:0% +Network it's just called an + + + align:start position:0% +Network it's just called an +RLC loop it's only got one Loop so it's + + align:start position:0% +RLC loop it's only got one Loop so it's + + + align:start position:0% +RLC loop it's only got one Loop so it's +a really simple Network it's the r + + align:start position:0% +a really simple Network it's the r + + + align:start position:0% +a really simple Network it's the r +stands for a + + align:start position:0% +stands for a + + + align:start position:0% +stands for a +resistance to the flow the L stands for + + align:start position:0% +resistance to the flow the L stands for + + + align:start position:0% +resistance to the flow the L stands for +an + + align:start position:0% +an + + + align:start position:0% +an +inductance and the C is the capacitance + + align:start position:0% +inductance and the C is the capacitance + + + align:start position:0% +inductance and the C is the capacitance +those are the three elements of a simple + + align:start position:0% +those are the three elements of a simple + + + align:start position:0% +those are the three elements of a simple +linear constant + + align:start position:0% +linear constant + + + align:start position:0% +linear constant +coefficient uh uh problem associated + + align:start position:0% +coefficient uh uh problem associated + + + align:start position:0% +coefficient uh uh problem associated +with one Loop and then there's a switch + + align:start position:0% +with one Loop and then there's a switch + + + align:start position:0% +with one Loop and then there's a switch +which I'll close and the flow will begin + + align:start position:0% +which I'll close and the flow will begin + + + align:start position:0% +which I'll close and the flow will begin +and there's a voltage source or like a + + align:start position:0% +and there's a voltage source or like a + + + align:start position:0% +and there's a voltage source or like a +battery that uh or maybe + + align:start position:0% +battery that uh or maybe + + + align:start position:0% +battery that uh or maybe +let's make it an let's make this + + align:start position:0% +let's make it an let's make this + + + align:start position:0% +let's make it an let's make this +alternating current so the voltage + + align:start position:0% +alternating current so the voltage + + + align:start position:0% +alternating current so the voltage +source will be uh some voltage times an + + align:start position:0% +source will be uh some voltage times an + + + align:start position:0% +source will be uh some voltage times an +e to the I Omega + + align:start position:0% +e to the I Omega + + + align:start position:0% +e to the I Omega +T so we're we're going to have + + align:start position:0% +T so we're we're going to have + + + align:start position:0% +T so we're we're going to have +alternating current and the question is + + align:start position:0% +alternating current and the question is + + + align:start position:0% +alternating current and the question is +what + + align:start position:0% +what + + + align:start position:0% +what +is the current the current will we have + + align:start position:0% +is the current the current will we have + + + align:start position:0% +is the current the current will we have +to find the current I so the current is + + align:start position:0% +to find the current I so the current is + + + align:start position:0% +to find the current I so the current is +I of + + align:start position:0% +I of + + + align:start position:0% +I of +T is the + + align:start position:0% +T is the + + + align:start position:0% +T is the +current going around the + + align:start position:0% + + + + align:start position:0% + +loop and we so our differential equation + + align:start position:0% +loop and we so our differential equation + + + align:start position:0% +loop and we so our differential equation +will have that unknown I of T rather + + align:start position:0% +will have that unknown I of T rather + + + align:start position:0% +will have that unknown I of T rather +than my usual y I'm going to use I for + + align:start position:0% +than my usual y I'm going to use I for + + + align:start position:0% +than my usual y I'm going to use I for +current okay again this is an + + align:start position:0% +current okay again this is an + + + align:start position:0% +current okay again this is an +RLC Loop that + + align:start position:0% +RLC Loop that + + + align:start position:0% +RLC Loop that +everybody has to + + align:start position:0% +everybody has to + + + align:start position:0% +everybody has to +understand as in in the in Electrical uh + + align:start position:0% +understand as in in the in Electrical uh + + + align:start position:0% +understand as in in the in Electrical uh +uh + + align:start position:0% +uh + + + align:start position:0% +uh +engineering okay so I'm going to have a + + align:start position:0% +engineering okay so I'm going to have a + + + align:start position:0% +engineering okay so I'm going to have a +second order differential equation well + + align:start position:0% +second order differential equation well + + + align:start position:0% +second order differential equation well +you'll see what that equation is so the + + align:start position:0% +you'll see what that equation is so the + + + align:start position:0% +you'll see what that equation is so the +you remember ohms law that the voltage + + align:start position:0% +you remember ohms law that the voltage + + + align:start position:0% +you remember ohms law that the voltage +is the current times the resistance so + + align:start position:0% +is the current times the resistance so + + + align:start position:0% +is the current times the resistance so +this is this gives me a a a voltage + + align:start position:0% +this is this gives me a a a voltage + + + align:start position:0% +this is this gives me a a a voltage +across the resistor if the if the + + align:start position:0% +across the resistor if the if the + + + align:start position:0% +across the resistor if the if the +current is I and the resistance is R + + align:start position:0% +current is I and the resistance is R + + + align:start position:0% +current is I and the resistance is R +then the voltage drop from here to here + + align:start position:0% +then the voltage drop from here to here + + + align:start position:0% +then the voltage drop from here to here +is I * R so that's that + + align:start position:0% + + + + align:start position:0% + +term but now I I have uh also my current + + align:start position:0% +term but now I I have uh also my current + + + align:start position:0% +term but now I I have uh also my current +is changing it with time it's Al this is + + align:start position:0% +is changing it with time it's Al this is + + + align:start position:0% +is changing it with time it's Al this is +alternating current it's going up and + + align:start position:0% +alternating current it's going up and + + + align:start position:0% +alternating current it's going up and +down so there's a the current through is + + align:start position:0% +down so there's a the current through is + + + align:start position:0% +down so there's a the current through is +is also going through the inductance + + align:start position:0% +is also going through the inductance + + + align:start position:0% +is also going through the inductance +and there + + align:start position:0% +and there + + + align:start position:0% +and there +the voltage drop across the inductance + + align:start position:0% +the voltage drop across the inductance + + + align:start position:0% +the voltage drop across the inductance +has this form the derivative of of the + + align:start position:0% +has this form the derivative of of the + + + align:start position:0% +has this form the derivative of of the +current comes into it and in the + + align:start position:0% +current comes into it and in the + + + align:start position:0% +current comes into it and in the +capacitance which is building up charge + + align:start position:0% +capacitance which is building up charge + + + align:start position:0% +capacitance which is building up charge +the integral of the current comes in so + + align:start position:0% +the integral of the current comes in so + + + align:start position:0% +the integral of the current comes in so +that's that's the physical + + align:start position:0% +that's that's the physical + + + align:start position:0% +that's that's the physical +equation that expresses this voltage law + + align:start position:0% +equation that expresses this voltage law + + + align:start position:0% +equation that expresses this voltage law +which says that if I that around a + + align:start position:0% +which says that if I that around a + + + align:start position:0% +which says that if I that around a +closed loop this is a + + align:start position:0% +closed loop this is a + + + align:start position:0% +closed loop this is a +closed Loops are + + align:start position:0% +closed Loops are + + + align:start position:0% +closed Loops are +closed add to zero so I have four terms + + align:start position:0% +closed add to zero so I have four terms + + + align:start position:0% +closed add to zero so I have four terms +and they combine to give zero okay so + + align:start position:0% +and they combine to give zero okay so + + + align:start position:0% +and they combine to give zero okay so +there's an equation I'd like to + + align:start position:0% +there's an equation I'd like to + + + align:start position:0% +there's an equation I'd like to +solve and how am I going to solve that + + align:start position:0% +solve and how am I going to solve that + + + align:start position:0% +solve and how am I going to solve that +equation by the standard idea which + + align:start position:0% +equation by the standard idea which + + + align:start position:0% +equation by the standard idea which +applies when I have constant + + align:start position:0% +applies when I have constant + + + align:start position:0% +applies when I have constant +coefficients and I have a pure + + align:start position:0% +coefficients and I have a pure + + + align:start position:0% +coefficients and I have a pure +exponential + + align:start position:0% +exponential + + + align:start position:0% +exponential +uh forcing term I look for a solution + + align:start position:0% +uh forcing term I look for a solution + + + align:start position:0% +uh forcing term I look for a solution +that is a multiple of that exponential + + align:start position:0% +that is a multiple of that exponential + + + align:start position:0% +that is a multiple of that exponential +right the solution to differential + + align:start position:0% +right the solution to differential + + + align:start position:0% +right the solution to differential +equations with constant coefficients if + + align:start position:0% +equations with constant coefficients if + + + align:start position:0% +equations with constant coefficients if +they have an exponential forcing then + + align:start position:0% +they have an exponential forcing then + + + align:start position:0% +they have an exponential forcing then +the solution is + + align:start position:0% +the solution is + + + align:start position:0% +the solution is +some uh I equals some um shall I say + + align:start position:0% +some uh I equals some um shall I say + + + align:start position:0% +some uh I equals some um shall I say +w e to the I Omega t + + align:start position:0% +w e to the I Omega t + + + align:start position:0% +w e to the I Omega t +some multiple of the of the source gives + + align:start position:0% +some multiple of the of the source gives + + + align:start position:0% +some multiple of the of the source gives +me the solution to that differential + + align:start position:0% +me the solution to that differential + + + align:start position:0% +me the solution to that differential +equation well it's actually a + + align:start position:0% +equation well it's actually a + + + align:start position:0% +equation well it's actually a +differential integral equation I can + + align:start position:0% +differential integral equation I can + + + align:start position:0% +differential integral equation I can +make it a more familiar looking + + align:start position:0% +make it a more familiar looking + + + align:start position:0% +make it a more familiar looking +differential equation by taking the + + align:start position:0% +differential equation by taking the + + + align:start position:0% +differential equation by taking the +derivative of every term suppose I do + + align:start position:0% +derivative of every term suppose I do + + + align:start position:0% +derivative of every term suppose I do +that suppose I take the derivative of + + align:start position:0% +that suppose I take the derivative of + + + align:start position:0% +that suppose I take the derivative of +every term just to make it look really + + align:start position:0% +every term just to make it look really + + + align:start position:0% +every term just to make it look really +familiar that would be L * I prime right + + align:start position:0% +familiar that would be L * I prime right + + + align:start position:0% +familiar that would be L * I prime right +taking the Der ative of the derivative + + align:start position:0% +taking the Der ative of the derivative + + + align:start position:0% +taking the Der ative of the derivative +this would be + + align:start position:0% +this would be + + + align:start position:0% +this would be +r i Prime the derivative of the integral + + align:start position:0% +r i Prime the derivative of the integral + + + align:start position:0% +r i Prime the derivative of the integral +would be just I itself so I'd have 1 / c + + align:start position:0% +would be just I itself so I'd have 1 / c + + + align:start position:0% +would be just I itself so I'd have 1 / c +i and I would have the derivative here I + + align:start position:0% +i and I would have the derivative here I + + + align:start position:0% +i and I would have the derivative here I +Omega v e to the I Omega + + align:start position:0% + + + + align:start position:0% + +T so it's just a standard second order + + align:start position:0% +T so it's just a standard second order + + + align:start position:0% +T so it's just a standard second order +constant coefficient linear differential + + align:start position:0% +constant coefficient linear differential + + + align:start position:0% +constant coefficient linear differential +equation equation and in fact you're if + + align:start position:0% +equation equation and in fact you're if + + + align:start position:0% +equation equation and in fact you're if +you were a mechanical engineer you would + + align:start position:0% +you were a mechanical engineer you would + + + align:start position:0% +you were a mechanical engineer you would +look at that and say well I don't know + + align:start position:0% +look at that and say well I don't know + + + align:start position:0% +look at that and say well I don't know +what LR and one over c stand for but I + + align:start position:0% +what LR and one over c stand for but I + + + align:start position:0% +what LR and one over c stand for but I +know that I should see the mass the + + align:start position:0% +know that I should see the mass the + + + align:start position:0% +know that I should see the mass the +damping and the stiffness there so we + + align:start position:0% +damping and the stiffness there so we + + + align:start position:0% +damping and the stiffness there so we +have a complete parallel between two + + align:start position:0% +have a complete parallel between two + + + align:start position:0% +have a complete parallel between two +important fields of engineering the + + align:start position:0% +important fields of engineering the + + + align:start position:0% +important fields of engineering the +electrical engineering with LR and 1 + + align:start position:0% +electrical engineering with LR and 1 + + + align:start position:0% +electrical engineering with LR and 1 +over C mechanical engineering with + + align:start position:0% +over C mechanical engineering with + + + align:start position:0% +over C mechanical engineering with +m B for damping and K for stiffness and + + align:start position:0% +m B for damping and K for stiffness and + + + align:start position:0% +m B for damping and K for stiffness and +actually that parallel allows uh allowed + + align:start position:0% +actually that parallel allows uh allowed + + + align:start position:0% +actually that parallel allows uh allowed +analog + + align:start position:0% +analog + + + align:start position:0% +analog +computers which were which came before + + align:start position:0% +computers which were which came before + + + align:start position:0% +computers which were which came before +uh digital computers and lost out in + + align:start position:0% +uh digital computers and lost out in + + + align:start position:0% +uh digital computers and lost out in +that uh + + align:start position:0% +that uh + + + align:start position:0% +that uh +competition an analog computer was just + + align:start position:0% +competition an analog computer was just + + + align:start position:0% +competition an analog computer was just +solving this + + align:start position:0% +solving this + + + align:start position:0% +solving this +linear equation by actually a opposing + + align:start position:0% +linear equation by actually a opposing + + + align:start position:0% +linear equation by actually a opposing +the voltage and measuring the + + align:start position:0% +the voltage and measuring the + + + align:start position:0% +the voltage and measuring the +current so that an analog computer + + align:start position:0% +current so that an analog computer + + + align:start position:0% +current so that an analog computer +actually solved the equation by creating + + align:start position:0% +actually solved the equation by creating + + + align:start position:0% +actually solved the equation by creating +the model and measuring the answer okay + + align:start position:0% +the model and measuring the answer okay + + + align:start position:0% +the model and measuring the answer okay +but we're not creating an analog + + align:start position:0% +but we're not creating an analog + + + align:start position:0% +but we're not creating an analog +computer here we're just doing just + + align:start position:0% +computer here we're just doing just + + + align:start position:0% +computer here we're just doing just +doing differential equations so why + + align:start position:0% +doing differential equations so why + + + align:start position:0% +doing differential equations so why +don't I figure out what that W is so so + + align:start position:0% +don't I figure out what that W is so so + + + align:start position:0% +don't I figure out what that W is so so +what am I going to do as always as + + align:start position:0% +what am I going to do as always as + + + align:start position:0% +what am I going to do as always as +always I have this equation I have a + + align:start position:0% +always I have this equation I have a + + + align:start position:0% +always I have this equation I have a +pure exponential I look for a solution + + align:start position:0% +pure exponential I look for a solution + + + align:start position:0% +pure exponential I look for a solution +of that same form I plug it in and I get + + align:start position:0% +of that same form I plug it in and I get + + + align:start position:0% +of that same form I plug it in and I get +an equation for w that's exactly what + + align:start position:0% +an equation for w that's exactly what + + + align:start position:0% +an equation for w that's exactly what +I'll do on the next board I'll plug I'll + + align:start position:0% +I'll do on the next board I'll plug I'll + + + align:start position:0% +I'll do on the next board I'll plug I'll +put w e to the I Omega T into this + + align:start position:0% +put w e to the I Omega T into this + + + align:start position:0% +put w e to the I Omega T into this +equation and uh find W okay let's do + + align:start position:0% + + + + align:start position:0% + +it okay maybe I bring that down just a + + align:start position:0% +it okay maybe I bring that down just a + + + align:start position:0% +it okay maybe I bring that down just a +hair and you can I'll do it here where + + align:start position:0% +hair and you can I'll do it here where + + + align:start position:0% +hair and you can I'll do it here where +you can watch me do it so I I have L * + + align:start position:0% +you can watch me do it so I I have L * + + + align:start position:0% +you can watch me do it so I I have L * +the derivative so I have + + align:start position:0% +the derivative so I have + + + align:start position:0% +the derivative so I have +L the derivative will bring down an i + + align:start position:0% +L the derivative will bring down an i + + + align:start position:0% +L the derivative will bring down an i +Omega + + align:start position:0% +Omega + + + align:start position:0% +Omega +L everything is going to multiply + + align:start position:0% + + + + align:start position:0% + +W and match V that's + + align:start position:0% +W and match V that's + + + align:start position:0% +W and match V that's +that's when I put this into the equation + + align:start position:0% +that's when I put this into the equation + + + align:start position:0% +that's when I put this into the equation +the derivative is is an i Omega + + align:start position:0% +the derivative is is an i Omega + + + align:start position:0% +the derivative is is an i Omega +l w e to the I Omega T and it's matching + + align:start position:0% +l w e to the I Omega T and it's matching + + + align:start position:0% +l w e to the I Omega T and it's matching +v e to the I Omega T now what what + + align:start position:0% +v e to the I Omega T now what what + + + align:start position:0% +v e to the I Omega T now what what +happens when I + + align:start position:0% +happens when I + + + align:start position:0% +happens when I +put I in for that second term r i just + + align:start position:0% +put I in for that second term r i just + + + align:start position:0% +put I in for that second term r i just +get an r r * W * e to the I Omega t no + + align:start position:0% +get an r r * W * e to the I Omega t no + + + align:start position:0% +get an r r * W * e to the I Omega t no +problem and now finally a 1 / C the + + align:start position:0% +problem and now finally a 1 / C the + + + align:start position:0% +problem and now finally a 1 / C the +integral the integral of + + align:start position:0% +integral the integral of + + + align:start position:0% +integral the integral of +the exponential brings down + + align:start position:0% +the exponential brings down + + + align:start position:0% +the exponential brings down +oh let me put it in the denominator + + align:start position:0% +oh let me put it in the denominator + + + align:start position:0% +oh let me put it in the denominator +neatly brings down I divide by I Omega + + align:start position:0% +neatly brings down I divide by I Omega + + + align:start position:0% +neatly brings down I divide by I Omega +when I integrate e to the I Omega T I + + align:start position:0% +when I integrate e to the I Omega T I + + + align:start position:0% +when I integrate e to the I Omega T I +have a division by I + + align:start position:0% +have a division by I + + + align:start position:0% +have a division by I +Omega that's it that's it those are the + + align:start position:0% +Omega that's it that's it those are the + + + align:start position:0% +Omega that's it that's it those are the +three terms that come times W the + + align:start position:0% +three terms that come times W the + + + align:start position:0% +three terms that come times W the +unknown this is to + + align:start position:0% +unknown this is to + + + align:start position:0% +unknown this is to +find + + align:start position:0% +find + + + align:start position:0% +find +and of course we find it right away we + + align:start position:0% +and of course we find it right away we + + + align:start position:0% +and of course we find it right away we +find W is + + align:start position:0% +find W is + + + align:start position:0% +find W is +V over and now we're seeing this I Omega + + align:start position:0% +V over and now we're seeing this I Omega + + + align:start position:0% +V over and now we're seeing this I Omega +l+ R oh let me combine the I Omega the U + + align:start position:0% +l+ R oh let me combine the I Omega the U + + + align:start position:0% +l+ R oh let me combine the I Omega the U +combine the real part and the imaginary + + align:start position:0% +combine the real part and the imaginary + + + align:start position:0% +combine the real part and the imaginary +part the real part is + + align:start position:0% +part the real part is + + + align:start position:0% +part the real part is +r and the imaginary part is I Omega L + + align:start position:0% +r and the imaginary part is I Omega L + + + align:start position:0% +r and the imaginary part is I Omega L +minus 1/ I Omega + + align:start position:0% + + + + align:start position:0% + +C + + align:start position:0% +C + + + align:start position:0% +C +straightforward and that has a + + align:start position:0% +straightforward and that has a + + + align:start position:0% +straightforward and that has a +name that is the + + align:start position:0% +name that is the + + + align:start position:0% +name that is the +resistance but when there's also a terms + + align:start position:0% +resistance but when there's also a terms + + + align:start position:0% +resistance but when there's also a terms +coming from an inductance and a + + align:start position:0% +coming from an inductance and a + + + align:start position:0% +coming from an inductance and a +capacitance then the whole thing is + + align:start position:0% +capacitance then the whole thing is + + + align:start position:0% +capacitance then the whole thing is +called the impedance so this whole thing + + align:start position:0% +called the impedance so this whole thing + + + align:start position:0% +called the impedance so this whole thing +this + + align:start position:0% +this + + + align:start position:0% +this +whole + + align:start position:0% +whole + + + align:start position:0% +whole +denominator is called the complex + + align:start position:0% + + + + align:start position:0% + +impedance believe me all these ideas are + + align:start position:0% +impedance believe me all these ideas are + + + align:start position:0% +impedance believe me all these ideas are +so important that they're all all + + align:start position:0% +so important that they're all all + + + align:start position:0% +so important that they're all all +there's a whole vocabulary here but you + + align:start position:0% +there's a whole vocabulary here but you + + + align:start position:0% +there's a whole vocabulary here but you +you see we've done exactly the same + + align:start position:0% +you see we've done exactly the same + + + align:start position:0% +you see we've done exactly the same +thing for other constant coefficient + + align:start position:0% +thing for other constant coefficient + + + align:start position:0% +thing for other constant coefficient +equations we just called the + + align:start position:0% +equations we just called the + + + align:start position:0% +equations we just called the +coefficients ABC or maybe MB K and now + + align:start position:0% +coefficients ABC or maybe MB K and now + + + align:start position:0% +coefficients ABC or maybe MB K and now +we have slightly different letters but + + align:start position:0% +we have slightly different letters but + + + align:start position:0% +we have slightly different letters but +we don't have a new idea here the the + + align:start position:0% +we don't have a new idea here the the + + + align:start position:0% +we don't have a new idea here the the +idea is this one over that one over the + + align:start position:0% +idea is this one over that one over the + + + align:start position:0% +idea is this one over that one over the +impedance that will be the transfer + + align:start position:0% +impedance that will be the transfer + + + align:start position:0% +impedance that will be the transfer +function which multiplies the the the um + + align:start position:0% +function which multiplies the the the um + + + align:start position:0% +function which multiplies the the the um +source to give the to give the complex + + align:start position:0% +source to give the to give the complex + + + align:start position:0% +source to give the to give the complex +number W and W is a complex number I + + align:start position:0% +number W and W is a complex number I + + + align:start position:0% +number W and W is a complex number I +have to now think about that what's this + + align:start position:0% +have to now think about that what's this + + + align:start position:0% +have to now think about that what's this +and that impedance is always called + + align:start position:0% + + + + align:start position:0% + +Z so that we now have a new letter for + + align:start position:0% +Z so that we now have a new letter for + + + align:start position:0% +Z so that we now have a new letter for +the important quantity that shows up in + + align:start position:0% +the important quantity that shows up in + + + align:start position:0% +the important quantity that shows up in +the denominator there and again its real + + align:start position:0% +the denominator there and again its real + + + align:start position:0% +the denominator there and again its real +part is the resistance its imaginary + + align:start position:0% +part is the resistance its imaginary + + + align:start position:0% +part is the resistance its imaginary +part comes from L and C oh so we we can + + align:start position:0% +part comes from L and C oh so we we can + + + align:start position:0% +part comes from L and C oh so we we can +easily see how large what's the size of + + align:start position:0% +easily see how large what's the size of + + + align:start position:0% +easily see how large what's the size of +that + + align:start position:0% +that + + + align:start position:0% +that +impedance what's what's going to be the + + align:start position:0% +impedance what's what's going to be the + + + align:start position:0% +impedance what's what's going to be the +magnitude of this uh + + align:start position:0% +magnitude of this uh + + + align:start position:0% +magnitude of this uh +current we we want the size of that + + align:start position:0% +current we we want the size of that + + + align:start position:0% +current we we want the size of that +number V is the size of the voltage here + + align:start position:0% +number V is the size of the voltage here + + + align:start position:0% +number V is the size of the voltage here +is the size of the impedance and the + + align:start position:0% +is the size of the impedance and the + + + align:start position:0% +is the size of the impedance and the +answer will give us the size of w i I'm + + align:start position:0% +answer will give us the size of w i I'm + + + align:start position:0% +answer will give us the size of w i I'm +using size or magnitude to say that when + + align:start position:0% +using size or magnitude to say that when + + + align:start position:0% +using size or magnitude to say that when +I only do magnitudes you won't be seeing + + align:start position:0% +I only do magnitudes you won't be seeing + + + align:start position:0% +I only do magnitudes you won't be seeing +the phase lag so complex numbers like + + align:start position:0% +the phase lag so complex numbers like + + + align:start position:0% +the phase lag so complex numbers like +this complex number has a magnitude + + align:start position:0% +this complex number has a magnitude + + + align:start position:0% +this complex number has a magnitude +which we're about to write down and also + + align:start position:0% +which we're about to write down and also + + + align:start position:0% +which we're about to write down and also +it has a phase lag that tells that tells + + align:start position:0% +it has a phase lag that tells that tells + + + align:start position:0% +it has a phase lag that tells that tells +us how much is in the imaginary part and + + align:start position:0% +us how much is in the imaginary part and + + + align:start position:0% +us how much is in the imaginary part and +how much is in the real part but the + + align:start position:0% +how much is in the real part but the + + + align:start position:0% +how much is in the real part but the +magnitude is easy What's the magnitude + + align:start position:0% +magnitude is easy What's the magnitude + + + align:start position:0% +magnitude is easy What's the magnitude +of a complex number it's the real part + + align:start position:0% +of a complex number it's the real part + + + align:start position:0% +of a complex number it's the real part +squared and the imaginary part squared + + align:start position:0% +squared and the imaginary part squared + + + align:start position:0% +squared and the imaginary part squared +oh that should have been a plus there I + + align:start position:0% +oh that should have been a plus there I + + + align:start position:0% +oh that should have been a plus there I +think I don't know how it became a minus + + align:start position:0% +think I don't know how it became a minus + + + align:start position:0% +think I don't know how it became a minus +okay uh it will become a minus so I was + + align:start position:0% +okay uh it will become a minus so I was + + + align:start position:0% +okay uh it will become a minus so I was +thinking if I put the I up there let me + + align:start position:0% +thinking if I put the I up there let me + + + align:start position:0% +thinking if I put the I up there let me +show you what I'm saying the imaginary + + align:start position:0% +show you what I'm saying the imaginary + + + align:start position:0% +show you what I'm saying the imaginary +part is Omega + + align:start position:0% +part is Omega + + + align:start position:0% +part is Omega +L minus 1 over Omega + + align:start position:0% +L minus 1 over Omega + + + align:start position:0% +L minus 1 over Omega +C what I'm saying is that if I put the I + + align:start position:0% +C what I'm saying is that if I put the I + + + align:start position:0% +C what I'm saying is that if I put the I +up there + + align:start position:0% +up there + + + align:start position:0% +up there +then 1 over I is minus I that's the + + align:start position:0% +then 1 over I is minus I that's the + + + align:start position:0% +then 1 over I is minus I that's the +brilliant uh step I just took there so + + align:start position:0% +brilliant uh step I just took there so + + + align:start position:0% +brilliant uh step I just took there so +all that squar + + align:start position:0% +all that squar + + + align:start position:0% +all that squar +are you okay with that it's the + + align:start position:0% +are you okay with that it's the + + + align:start position:0% +are you okay with that it's the +imaginary it's the real part squared + + align:start position:0% +imaginary it's the real part squared + + + align:start position:0% +imaginary it's the real part squared +which is the resistance and this + + align:start position:0% +which is the resistance and this + + + align:start position:0% +which is the resistance and this +combination gives the imaginary part we + + align:start position:0% +combination gives the imaginary part we + + + align:start position:0% +combination gives the imaginary part we +square that that's maybe called the + + align:start position:0% +square that that's maybe called the + + + align:start position:0% +square that that's maybe called the +reactants and the sum of those squares + + align:start position:0% +reactants and the sum of those squares + + + align:start position:0% +reactants and the sum of those squares +is the impedance squared the + + align:start position:0% +is the impedance squared the + + + align:start position:0% +is the impedance squared the +magnitude okay so that's + + align:start position:0% +magnitude okay so that's + + + align:start position:0% +magnitude okay so that's +uh we have essentially successfully + + align:start position:0% +uh we have essentially successfully + + + align:start position:0% +uh we have essentially successfully +solved a uh second order constant + + align:start position:0% +solved a uh second order constant + + + align:start position:0% +solved a uh second order constant +coefficient single equation for the + + align:start position:0% +coefficient single equation for the + + + align:start position:0% +coefficient single equation for the +current okay what to do now just let me + + align:start position:0% +current okay what to do now just let me + + + align:start position:0% +current okay what to do now just let me +add a little little bit + + align:start position:0% +add a little little bit + + + align:start position:0% +add a little little bit +more maybe a maybe just a + + align:start position:0% +more maybe a maybe just a + + + align:start position:0% +more maybe a maybe just a +comment that that video was about one + + align:start position:0% +comment that that video was about one + + + align:start position:0% +comment that that video was about one +Loop when I told Dr Mohler that one of + + align:start position:0% +Loop when I told Dr Mohler that one of + + + align:start position:0% +Loop when I told Dr Mohler that one of +the applications one of the real + + align:start position:0% +the applications one of the real + + + align:start position:0% +the applications one of the real +applications in this series of videos + + align:start position:0% +applications in this series of videos + + + align:start position:0% +applications in this series of videos +would be an RL C circuit his reply was + + align:start position:0% +would be an RL C circuit his reply was + + + align:start position:0% +would be an RL C circuit his reply was +an RLC circuit is not an application not + + align:start position:0% +an RLC circuit is not an application not + + + align:start position:0% +an RLC circuit is not an application not +a realistic application one Loop so what + + align:start position:0% +a realistic application one Loop so what + + + align:start position:0% +a realistic application one Loop so what +H how do we proceed with a full scale + + align:start position:0% +H how do we proceed with a full scale + + + align:start position:0% +H how do we proceed with a full scale +circuit with many nodes many resistors + + align:start position:0% +circuit with many nodes many resistors + + + align:start position:0% +circuit with many nodes many resistors +many conductors many many edges well we + + align:start position:0% +many conductors many many edges well we + + + align:start position:0% +many conductors many many edges well we +have a big decision to make and that's + + align:start position:0% +have a big decision to make and that's + + + align:start position:0% +have a big decision to make and that's +the comment I want to make they have a + + align:start position:0% +the comment I want to make they have a + + + align:start position:0% +the comment I want to make they have a +choice they can use Kirk off's current + + align:start position:0% +choice they can use Kirk off's current + + + align:start position:0% +choice they can use Kirk off's current +law at the + + align:start position:0% +law at the + + + align:start position:0% +law at the +nodes and solve for the voltages at + + align:start position:0% +nodes and solve for the voltages at + + + align:start position:0% +nodes and solve for the voltages at +those + + align:start position:0% +those + + + align:start position:0% +those +nodes or they can do as we did for one + + align:start position:0% +nodes or they can do as we did for one + + + align:start position:0% +nodes or they can do as we did for one +Loop use Kirk's voltage law around that + + align:start position:0% +Loop use Kirk's voltage law around that + + + align:start position:0% +Loop use Kirk's voltage law around that +one Loop which said that the total + + align:start position:0% +one Loop which said that the total + + + align:start position:0% +one Loop which said that the total +voltage that the currents in the loop + + align:start position:0% +voltage that the currents in the loop + + + align:start position:0% +voltage that the currents in the loop +gave a total voltage drop adding to zero + + align:start position:0% +gave a total voltage drop adding to zero + + + align:start position:0% +gave a total voltage drop adding to zero +so we we solved the current equation for + + align:start position:0% +so we we solved the current equation for + + + align:start position:0% +so we we solved the current equation for +the unknown I this is what we did for + + align:start position:0% +the unknown I this is what we did for + + + align:start position:0% +the unknown I this is what we did for +one Loop + + align:start position:0% +one Loop + + + align:start position:0% +one Loop +my message is just for a big system this + + align:start position:0% +my message is just for a big system this + + + align:start position:0% +my message is just for a big system this +is the winner so right writing down the + + align:start position:0% +is the winner so right writing down the + + + align:start position:0% +is the winner so right writing down the +equations in terms of Kirk off's current + + align:start position:0% +equations in terms of Kirk off's current + + + align:start position:0% +equations in terms of Kirk off's current +law that the currents at we get the the + + align:start position:0% +law that the currents at we get the the + + + align:start position:0% +law that the currents at we get the the +nodal picture the picture with an + + align:start position:0% +nodal picture the picture with an + + + align:start position:0% +nodal picture the picture with an +equation for every node instead of the + + align:start position:0% +equation for every node instead of the + + + align:start position:0% +equation for every node instead of the +picture for an equation for every Loop + + align:start position:0% +picture for an equation for every Loop + + + align:start position:0% +picture for an equation for every Loop +because it's not so easy to see which + + align:start position:0% +because it's not so easy to see which + + + align:start position:0% +because it's not so easy to see which +are the loops to consider or and which + + align:start position:0% +are the loops to consider or and which + + + align:start position:0% +are the loops to consider or and which +Loops are uh or combinations of other + + align:start position:0% +Loops are uh or combinations of other + + + align:start position:0% +Loops are uh or combinations of other +Loops so this becomes the linear algebra + + align:start position:0% +Loops so this becomes the linear algebra + + + align:start position:0% +Loops so this becomes the linear algebra +is the question and the linear algebra + + align:start position:0% +is the question and the linear algebra + + + align:start position:0% +is the question and the linear algebra +to get the loop picture independent and + + align:start position:0% +to get the loop picture independent and + + + align:start position:0% +to get the loop picture independent and +clear is more difficult than the node + + align:start position:0% +clear is more difficult than the node + + + align:start position:0% +clear is more difficult than the node +picture the node picture with the + + align:start position:0% +picture the node picture with the + + + align:start position:0% +picture the node picture with the +unknown uh + + align:start position:0% +unknown uh + + + align:start position:0% +unknown uh +voltages + + align:start position:0% +voltages + + + align:start position:0% +voltages +V on the at at the + + align:start position:0% +V on the at at the + + + align:start position:0% +V on the at at the +nodes uh is the good one and The Matrix + + align:start position:0% +nodes uh is the good one and The Matrix + + + align:start position:0% +nodes uh is the good one and The Matrix +that comes into that is the incidence + + align:start position:0% +that comes into that is the incidence + + + align:start position:0% +that comes into that is the incidence +Matrix it it connects uh nodes and edges + + align:start position:0% +Matrix it it connects uh nodes and edges + + + align:start position:0% +Matrix it it connects uh nodes and edges +it says how the network is put together + + align:start position:0% +it says how the network is put together + + + align:start position:0% +it says how the network is put together +and that Matrix I'll study with a little + + align:start position:0% +and that Matrix I'll study with a little + + + align:start position:0% +and that Matrix I'll study with a little +bit of linear algebra so that comes in a + + align:start position:0% +bit of linear algebra so that comes in a + + + align:start position:0% +bit of linear algebra so that comes in a +later video if you look for incidence + + align:start position:0% +later video if you look for incidence + + + align:start position:0% +later video if you look for incidence +matrices you'll see probably two videos + + align:start position:0% +matrices you'll see probably two videos + + + align:start position:0% +matrices you'll see probably two videos +about those very very important and + + align:start position:0% +about those very very important and + + + align:start position:0% +about those very very important and +beautiful matrices thank + + align:start position:0% +beautiful matrices thank + + + align:start position:0% +beautiful matrices thank +you \ No newline at end of file diff --git a/7c2bwfiDCgs.txt b/7c2bwfiDCgs.txt new file mode 100644 index 0000000000000000000000000000000000000000..b175addb96e33bc5f66fa7e4982b05ad50448610 --- /dev/null +++ b/7c2bwfiDCgs.txt @@ -0,0 +1,123 @@ +align:start position:0% + +so I decided to uh focus on Italian that + + align:start position:0% +so I decided to uh focus on Italian that + + + align:start position:0% +so I decided to uh focus on Italian that +the students would have a chance to use + + align:start position:0% +the students would have a chance to use + + + align:start position:0% +the students would have a chance to use +every day um but being grammatically + + align:start position:0% +every day um but being grammatically + + + align:start position:0% +every day um but being grammatically +correct + + align:start position:0% +correct + + + align:start position:0% +correct +so it it's not like um we didn't discuss + + align:start position:0% +so it it's not like um we didn't discuss + + + align:start position:0% +so it it's not like um we didn't discuss +literature and when we did some readings + + align:start position:0% +literature and when we did some readings + + + align:start position:0% +literature and when we did some readings +it was very basic readings from example + + align:start position:0% +it was very basic readings from example + + + align:start position:0% +it was very basic readings from example +from um books from children for children + + align:start position:0% +from um books from children for children + + + align:start position:0% +from um books from children for children +um um the basic idea was to give them + + align:start position:0% +um um the basic idea was to give them + + + align:start position:0% +um um the basic idea was to give them +the tools to be able to have a basic um + + align:start position:0% +the tools to be able to have a basic um + + + align:start position:0% +the tools to be able to have a basic um +communication uh so when I was choosing + + align:start position:0% +communication uh so when I was choosing + + + align:start position:0% +communication uh so when I was choosing +the vocabulary I was choosing vocabulary + + align:start position:0% +the vocabulary I was choosing vocabulary + + + align:start position:0% +the vocabulary I was choosing vocabulary +that every Italian would + + align:start position:0% +that every Italian would + + + align:start position:0% +that every Italian would +use in the kitchen daily and outside the + + align:start position:0% +use in the kitchen daily and outside the + + + align:start position:0% +use in the kitchen daily and outside the +kitchen in uh um personal + + align:start position:0% +kitchen in uh um personal + + + align:start position:0% +kitchen in uh um personal +interactions \ No newline at end of file diff --git a/7q32Wnm4dEw.txt b/7q32Wnm4dEw.txt new file mode 100644 index 0000000000000000000000000000000000000000..e19d64bae316ba6746fcbdfe12b16b22fea1d618 --- /dev/null +++ b/7q32Wnm4dEw.txt @@ -0,0 +1,2659 @@ +align:start position:0% + +the beginning of our analysis and still + + align:start position:0% +the beginning of our analysis and still + + + align:start position:0% +the beginning of our analysis and still +not solve differential equations but we + + align:start position:0% +not solve differential equations but we + + + align:start position:0% +not solve differential equations but we +will have now two particles a protein + + align:start position:0% +will have now two particles a protein + + + align:start position:0% +will have now two particles a protein +whose stories are going to be coordinate + + align:start position:0% +whose stories are going to be coordinate + + + align:start position:0% +whose stories are going to be coordinate +of the proton some index key for the + + align:start position:0% +of the proton some index key for the + + + align:start position:0% +of the proton some index key for the +protocol and momentum of the proton and + + align:start position:0% +protocol and momentum of the proton and + + + align:start position:0% +protocol and momentum of the proton and +there's an electron and there's the + + align:start position:0% +there's an electron and there's the + + + align:start position:0% +there's an electron and there's the +coordinates the three coordinates of the + + align:start position:0% +coordinates the three coordinates of the + + + align:start position:0% +coordinates the three coordinates of the +electron and the three components of the + + align:start position:0% +electron and the three components of the + + + align:start position:0% +electron and the three components of the +momentum of the electron and these are + + align:start position:0% +momentum of the electron and these are + + + align:start position:0% +momentum of the electron and these are +your canonical variables this means that + + align:start position:0% +your canonical variables this means that + + + align:start position:0% +your canonical variables this means that +the components of this object satisfy + + align:start position:0% +the components of this object satisfy + + + align:start position:0% +the components of this object satisfy +the standard commutation relations that + + align:start position:0% +the standard commutation relations that + + + align:start position:0% +the standard commutation relations that +is I have to write like this before they + + align:start position:0% +is I have to write like this before they + + + align:start position:0% +is I have to write like this before they +consider the coordinates of the problem + + align:start position:0% +consider the coordinates of the problem + + + align:start position:0% +consider the coordinates of the problem +the I component and the momentum of the + + align:start position:0% +the I component and the momentum of the + + + align:start position:0% +the I component and the momentum of the +problem the J component that's equal to + + align:start position:0% +problem the J component that's equal to + + + align:start position:0% +problem the J component that's equal to +I h-bar Delta I J + + align:start position:0% +I h-bar Delta I J + + + align:start position:0% +I h-bar Delta I J +you see we used to call for its x y&z + + align:start position:0% +you see we used to call for its x y&z + + + align:start position:0% +you see we used to call for its x y&z +and omega p h py PZ you could have + + align:start position:0% +and omega p h py PZ you could have + + + align:start position:0% +and omega p h py PZ you could have +called them x1 x2 x3 Omega P 1 P 2 P 3 + + align:start position:0% +called them x1 x2 x3 Omega P 1 P 2 P 3 + + + align:start position:0% +called them x1 x2 x3 Omega P 1 P 2 P 3 +and in that way you can use a Kronecker + + align:start position:0% +and in that way you can use a Kronecker + + + align:start position:0% +and in that way you can use a Kronecker +Delta over here so this are the + + align:start position:0% +Delta over here so this are the + + + align:start position:0% +Delta over here so this are the +commutation relations of XS FPS but X + + align:start position:0% +commutation relations of XS FPS but X + + + align:start position:0% +commutation relations of XS FPS but X +and P for a proton so the proton has its + + align:start position:0% +and P for a proton so the proton has its + + + align:start position:0% +and P for a proton so the proton has its +X has its peak and it behaves like an X + + align:start position:0% +X has its peak and it behaves like an X + + + align:start position:0% +X has its peak and it behaves like an X +and P this time the electron has its X + + align:start position:0% +and P this time the electron has its X + + + align:start position:0% +and P this time the electron has its X +its p and also behaves the same way as + + align:start position:0% +its p and also behaves the same way as + + + align:start position:0% +its p and also behaves the same way as +Hornets + + align:start position:0% + + + + align:start position:0% + +I see this is because X operator y + + align:start position:0% +I see this is because X operator y + + + align:start position:0% +I see this is because X operator y +operators Z operator you can call them X + + align:start position:0% +operators Z operator you can call them X + + + align:start position:0% +operators Z operator you can call them X +I operators with one two three + + align:start position:0% +I operators with one two three + + + align:start position:0% +I operators with one two three +the P X py PZ operators are better + + align:start position:0% +the P X py PZ operators are better + + + align:start position:0% +the P X py PZ operators are better +called P sub i with i running from 1 2 & + + align:start position:0% +called P sub i with i running from 1 2 & + + + align:start position:0% +called P sub i with i running from 1 2 & +3 and X be the first why the seconds + + align:start position:0% +3 and X be the first why the seconds + + + align:start position:0% +3 and X be the first why the seconds +even the left then the fact that the X + + align:start position:0% +even the left then the fact that the X + + + align:start position:0% +even the left then the fact that the X +just fails to compute with P X Y P Y Z + + align:start position:0% +just fails to compute with P X Y P Y Z + + + align:start position:0% +just fails to compute with P X Y P Y Z +first illumine with busy is X I PJ and + + align:start position:0% +first illumine with busy is X I PJ and + + + align:start position:0% +first illumine with busy is X I PJ and +call I h-bar Delta haiji and this is + + align:start position:0% +call I h-bar Delta haiji and this is + + + align:start position:0% +call I h-bar Delta haiji and this is +what I'm saying here this notation + + align:start position:0% +what I'm saying here this notation + + + align:start position:0% +what I'm saying here this notation +because there's too many subscripts + + align:start position:0% +because there's too many subscripts + + + align:start position:0% +because there's too many subscripts +there's a P for proto + + align:start position:0% +there's a P for proto + + + align:start position:0% +there's a P for proto +but there's an eye for the first second + + align:start position:0% +but there's an eye for the first second + + + align:start position:0% +but there's an eye for the first second +and third of all and there's the + + align:start position:0% +and third of all and there's the + + + align:start position:0% +and third of all and there's the +momentum of the proton which has 1 2 3 + + align:start position:0% +momentum of the proton which has 1 2 3 + + + align:start position:0% +momentum of the proton which has 1 2 3 +components so that those are our + + align:start position:0% +components so that those are our + + + align:start position:0% +components so that those are our +dynamical variables and then when we try + + align:start position:0% +dynamical variables and then when we try + + + align:start position:0% +dynamical variables and then when we try +to solve this you have the issue of wave + + align:start position:0% +to solve this you have the issue of wave + + + align:start position:0% +to solve this you have the issue of wave +functions what happens to the wave + + align:start position:0% +functions what happens to the wave + + + align:start position:0% +functions what happens to the wave +function should I invent a wave function + + align:start position:0% +function should I invent a wave function + + + align:start position:0% +function should I invent a wave function +for the electrode and we function for + + align:start position:0% +for the electrode and we function for + + + align:start position:0% +for the electrode and we function for +the proto no that's not good you should + + align:start position:0% +the proto no that's not good you should + + + align:start position:0% +the proto no that's not good you should +invent a wave function for everybody + + align:start position:0% +invent a wave function for everybody + + + align:start position:0% +invent a wave function for everybody +which is a wave function that depends on + + align:start position:0% +which is a wave function that depends on + + + align:start position:0% +which is a wave function that depends on +the coordinates X of the electron and if + + align:start position:0% +the coordinates X of the electron and if + + + align:start position:0% +the coordinates X of the electron and if +you have just an electron you have a + + align:start position:0% +you have just an electron you have a + + + align:start position:0% +you have just an electron you have a +wave function of the + + align:start position:0% +wave function of the + + + align:start position:0% +wave function of the +the Knights of the leg and now wait + + align:start position:0% +the Knights of the leg and now wait + + + align:start position:0% +the Knights of the leg and now wait +function that depends on the coordinates + + align:start position:0% +function that depends on the coordinates + + + align:start position:0% +function that depends on the coordinates +of the probe and how would you normalize + + align:start position:0% +of the probe and how would you normalize + + + align:start position:0% +of the probe and how would you normalize +it well this thing times the cube X e XV + + align:start position:0% +it well this thing times the cube X e XV + + + align:start position:0% +it well this thing times the cube X e XV +q X P is the probability VP to find the + + align:start position:0% +q X P is the probability VP to find the + + + align:start position:0% +q X P is the probability VP to find the +electric around a little Q about the + + align:start position:0% +electric around a little Q about the + + + align:start position:0% +electric around a little Q about the +point XE and the proton around a little + + align:start position:0% +point XE and the proton around a little + + + align:start position:0% +point XE and the proton around a little +cube around X P and then if you want to + + align:start position:0% +cube around X P and then if you want to + + + align:start position:0% +cube around X P and then if you want to +see what is the probability to find the + + align:start position:0% +see what is the probability to find the + + + align:start position:0% +see what is the probability to find the +electron at some point regardless of the + + align:start position:0% +electron at some point regardless of the + + + align:start position:0% +electron at some point regardless of the +product you integrate over the whole + + align:start position:0% +product you integrate over the whole + + + align:start position:0% +product you integrate over the whole +proton and then you should just have a + + align:start position:0% +proton and then you should just have a + + + align:start position:0% +proton and then you should just have a +wave as if you integrate this size + + align:start position:0% +wave as if you integrate this size + + + align:start position:0% +wave as if you integrate this size +squared + + align:start position:0% +squared + + + align:start position:0% +squared +I'm sorry x squared if you integrate + + align:start position:0% +I'm sorry x squared if you integrate + + + align:start position:0% +I'm sorry x squared if you integrate +this size squared over the product + + align:start position:0% +this size squared over the product + + + align:start position:0% +this size squared over the product +you're left with some probability + + align:start position:0% +you're left with some probability + + + align:start position:0% +you're left with some probability +density for the electrode so this is the + + align:start position:0% +density for the electrode so this is the + + + align:start position:0% +density for the electrode so this is the +good thing about having more and more + + align:start position:0% +good thing about having more and more + + + align:start position:0% +good thing about having more and more +particles you still have just one wave + + align:start position:0% +particles you still have just one wave + + + align:start position:0% +particles you still have just one wave +function and one Schroedinger equation + + align:start position:0% +function and one Schroedinger equation + + + align:start position:0% +function and one Schroedinger equation +you have more Cardinal is just one way + + align:start position:0% +you have more Cardinal is just one way + + + align:start position:0% +you have more Cardinal is just one way +function that's why people eventually + + align:start position:0% +function that's why people eventually + + + align:start position:0% +function that's why people eventually +talk about the wave function of the + + align:start position:0% +talk about the wave function of the + + + align:start position:0% +talk about the wave function of the +universe as saying well the whole + + align:start position:0% +universe as saying well the whole + + + align:start position:0% +universe as saying well the whole +universe has one wave function for every + + align:start position:0% +universe has one wave function for every + + + align:start position:0% +universe has one wave function for every +atom for every molecule for every + + align:start position:0% +atom for every molecule for every + + + align:start position:0% +atom for every molecule for every +elementary particle it's just one wave + + align:start position:0% +elementary particle it's just one wave + + + align:start position:0% +elementary particle it's just one wave +function that's nice about the Cheniere + + align:start position:0% +function that's nice about the Cheniere + + + align:start position:0% +function that's nice about the Cheniere +equation and ok so we have this and what + + align:start position:0% +equation and ok so we have this and what + + + align:start position:0% +equation and ok so we have this and what +is the Hamiltonian the Hamiltonian is + + align:start position:0% +is the Hamiltonian the Hamiltonian is + + + align:start position:0% +is the Hamiltonian the Hamiltonian is +the kinetic energy associated to the + + align:start position:0% +the kinetic energy associated to the + + + align:start position:0% +the kinetic energy associated to the +proton close the kinetic energy + + align:start position:0% +proton close the kinetic energy + + + align:start position:0% +proton close the kinetic energy +associated to the electron plus the + + align:start position:0% +associated to the electron plus the + + + align:start position:0% +associated to the electron plus the +potential energy which is depends of the + + align:start position:0% +potential energy which is depends of the + + + align:start position:0% +potential energy which is depends of the +distance between the electron and the + + align:start position:0% +distance between the electron and the + + + align:start position:0% +distance between the electron and the +pro and then you can write a + + align:start position:0% +pro and then you can write a + + + align:start position:0% +pro and then you can write a +differential equation the Schrodinger + + align:start position:0% +differential equation the Schrodinger + + + align:start position:0% +differential equation the Schrodinger +equation and the P of the proton would + + align:start position:0% +equation and the P of the proton would + + + align:start position:0% +equation and the P of the proton would +be thought as maybe X of the problem and + + align:start position:0% +be thought as maybe X of the problem and + + + align:start position:0% +be thought as maybe X of the problem and +the P of the Elector would be like DDX + + align:start position:0% +the P of the Elector would be like DDX + + + align:start position:0% +the P of the Elector would be like DDX +of the electric and that differential + + align:start position:0% +of the electric and that differential + + + align:start position:0% +of the electric and that differential +equation would make sense so what is our + + align:start position:0% +equation would make sense so what is our + + + align:start position:0% +equation would make sense so what is our +problem solving that we have can think + + align:start position:0% +problem solving that we have can think + + + align:start position:0% +problem solving that we have can think +in some way as a potential or a + + align:start position:0% +in some way as a potential or a + + + align:start position:0% +in some way as a potential or a +Schrodinger equation that involves just + + align:start position:0% +Schrodinger equation that involves just + + + align:start position:0% +Schrodinger equation that involves just +some distance that separates the + + align:start position:0% +some distance that separates the + + + align:start position:0% +some distance that separates the +particles and some equation for the rest + + align:start position:0% + + + + align:start position:0% + +so we have to change various so what is + + align:start position:0% +so we have to change various so what is + + + align:start position:0% +so we have to change various so what is +the change of variables motivate some of + + align:start position:0% +the change of variables motivate some of + + + align:start position:0% +the change of variables motivate some of +that well we have 42 pairs of canonical + + align:start position:0% +that well we have 42 pairs of canonical + + + align:start position:0% +that well we have 42 pairs of canonical +variables we have the proton canonical + + align:start position:0% +variables we have the proton canonical + + + align:start position:0% +variables we have the proton canonical +variables X and P of the proto and the + + align:start position:0% +variables X and P of the proto and the + + + align:start position:0% +variables X and P of the proto and the +electron canonical variables it should + + align:start position:0% +electron canonical variables it should + + + align:start position:0% +electron canonical variables it should +be of the electron so how can we have + + align:start position:0% +be of the electron so how can we have + + + align:start position:0% +be of the electron so how can we have +different kind of variables that will + + align:start position:0% +different kind of variables that will + + + align:start position:0% +different kind of variables that will +lead to a more interesting thing up we + + align:start position:0% +lead to a more interesting thing up we + + + align:start position:0% +lead to a more interesting thing up we +can imagine that maybe we should define + + align:start position:0% +can imagine that maybe we should define + + + align:start position:0% +can imagine that maybe we should define +a new X that is the difference for which + + align:start position:0% +a new X that is the difference for which + + + align:start position:0% +a new X that is the difference for which +of the magnitude of that X will be what + + align:start position:0% +of the magnitude of that X will be what + + + align:start position:0% +of the magnitude of that X will be what +we call our and that's true but it's not + + align:start position:0% +we call our and that's true but it's not + + + align:start position:0% +we call our and that's true but it's not +so easy to do that from the beginning so + + align:start position:0% +so easy to do that from the beginning so + + + align:start position:0% +so easy to do that from the beginning so +let's try to do what most people would + + align:start position:0% +let's try to do what most people would + + + align:start position:0% +let's try to do what most people would +do from experience and say I know + + align:start position:0% +do from experience and say I know + + + align:start position:0% +do from experience and say I know +there's something simple about a system + + align:start position:0% +there's something simple about a system + + + align:start position:0% +there's something simple about a system +of doing the rapping valley's center of + + align:start position:0% +of doing the rapping valley's center of + + + align:start position:0% +of doing the rapping valley's center of +mass if the center of mass moves with + + align:start position:0% +mass if the center of mass moves with + + + align:start position:0% +mass if the center of mass moves with +constant velocity that's what it does + + align:start position:0% +constant velocity that's what it does + + + align:start position:0% +constant velocity that's what it does +always so if classical notions of how + + align:start position:0% +always so if classical notions of how + + + align:start position:0% +always so if classical notions of how +you treat to body system can be used + + align:start position:0% +you treat to body system can be used + + + align:start position:0% +you treat to body system can be used +with prong setting we should be able to + + align:start position:0% +with prong setting we should be able to + + + align:start position:0% +with prong setting we should be able to +define a new quantum coordinate + + align:start position:0% +define a new quantum coordinate + + + align:start position:0% +define a new quantum coordinate +associated to the center of mass and + + align:start position:0% +associated to the center of mass and + + + align:start position:0% +associated to the center of mass and +then the quantum momentum associated + + align:start position:0% +then the quantum momentum associated + + + align:start position:0% +then the quantum momentum associated +percent and the center of mass of + + align:start position:0% +percent and the center of mass of + + + align:start position:0% +percent and the center of mass of +momentum is always the sum of the + + align:start position:0% +momentum is always the sum of the + + + align:start position:0% +momentum is always the sum of the +momenta so we will define a key a + + align:start position:0% +momenta so we will define a key a + + + align:start position:0% +momenta so we will define a key a +capital P a over made pieces will be + + align:start position:0% +capital P a over made pieces will be + + + align:start position:0% +capital P a over made pieces will be +always here + + align:start position:0% +always here + + + align:start position:0% +always here +supposed to have in for this for the + + align:start position:0% +supposed to have in for this for the + + + align:start position:0% +supposed to have in for this for the +little bar below this is the total P and + + align:start position:0% +little bar below this is the total P and + + + align:start position:0% +little bar below this is the total P and +it's going to be the time as the + + align:start position:0% +it's going to be the time as the + + + align:start position:0% +it's going to be the time as the +momentum of the proper flow the momentum + + align:start position:0% +momentum of the proper flow the momentum + + + align:start position:0% +momentum of the proper flow the momentum +of the electrons and now I want to + + align:start position:0% +of the electrons and now I want to + + + align:start position:0% +of the electrons and now I want to +define an X that goes with this P and by + + align:start position:0% +define an X that goes with this P and by + + + align:start position:0% +define an X that goes with this P and by +lad I need that this X must have a + + align:start position:0% +lad I need that this X must have a + + + align:start position:0% +lad I need that this X must have a +commutation relation with this speed + + align:start position:0% +commutation relation with this speed + + + align:start position:0% +commutation relation with this speed +that tells yes you are an X because X + + align:start position:0% +that tells yes you are an X because X + + + align:start position:0% +that tells yes you are an X because X +with P should be IH bar so whatever I + + align:start position:0% +with P should be IH bar so whatever I + + + align:start position:0% +with P should be IH bar so whatever I +define here that should happen now you + + align:start position:0% +define here that should happen now you + + + align:start position:0% +define here that should happen now you +can imagine that we usually do something + + align:start position:0% +can imagine that we usually do something + + + align:start position:0% +can imagine that we usually do something +like this we multiply each particle + + align:start position:0% +like this we multiply each particle + + + align:start position:0% +like this we multiply each particle +according to its mass so we're waiting + + align:start position:0% +according to its mass so we're waiting + + + align:start position:0% +according to its mass so we're waiting +the momentum associated up I'm sorry + + align:start position:0% +the momentum associated up I'm sorry + + + align:start position:0% +the momentum associated up I'm sorry +what are the positions XP x e associated + + align:start position:0% +what are the positions XP x e associated + + + align:start position:0% +what are the positions XP x e associated +to the mass and this of course would not + + align:start position:0% +to the mass and this of course would not + + + align:start position:0% +to the mass and this of course would not +have the right units doesn't have units + + align:start position:0% +have the right units doesn't have units + + + align:start position:0% +have the right units doesn't have units +of corn it so this is the center of mass + + align:start position:0% +of corn it so this is the center of mass + + + align:start position:0% +of corn it so this is the center of mass +so this will be center of mass quantum + + align:start position:0% +so this will be center of mass quantum + + + align:start position:0% +so this will be center of mass quantum +variables and in order to have unit you + + align:start position:0% +variables and in order to have unit you + + + align:start position:0% +variables and in order to have unit you +must divide by n mass so it's not too + + align:start position:0% +must divide by n mass so it's not too + + + align:start position:0% +must divide by n mass so it's not too +reasonable to put the sum of masses here + + align:start position:0% +reasonable to put the sum of masses here + + + align:start position:0% +reasonable to put the sum of masses here +that's how you define it + + align:start position:0% +that's how you define it + + + align:start position:0% +that's how you define it +away in classical mechanics and now we + + align:start position:0% +away in classical mechanics and now we + + + align:start position:0% +away in classical mechanics and now we +must ask is X with P the I component J + + align:start position:0% +must ask is X with P the I component J + + + align:start position:0% +must ask is X with P the I component J +component is it really people to our + + align:start position:0% +component is it really people to our + + + align:start position:0% +component is it really people to our +h-bar down and the answer I would say is + + align:start position:0% +h-bar down and the answer I would say is + + + align:start position:0% +h-bar down and the answer I would say is +yes because here let's do this one you + + align:start position:0% +yes because here let's do this one you + + + align:start position:0% +yes because here let's do this one you +would have MP x p i+ m e XE I over NP + + align:start position:0% +would have MP x p i+ m e XE I over NP + + + align:start position:0% +would have MP x p i+ m e XE I over NP +plus m e is it what you do one all the + + align:start position:0% +plus m e is it what you do one all the + + + align:start position:0% +plus m e is it what you do one all the +rest you should be able to do just + + align:start position:0% +rest you should be able to do just + + + align:start position:0% +rest you should be able to do just +without thinking up P on the other hand + + align:start position:0% +without thinking up P on the other hand + + + align:start position:0% +without thinking up P on the other hand +is P the momentum sub J plus the + + align:start position:0% +is P the momentum sub J plus the + + + align:start position:0% +is P the momentum sub J plus the +momentum of the electron sub J what is + + align:start position:0% +momentum of the electron sub J what is + + + align:start position:0% +momentum of the electron sub J what is +it equal to + + align:start position:0% +it equal to + + + align:start position:0% +it equal to +and then we say look from XP with + + align:start position:0% +and then we say look from XP with + + + align:start position:0% +and then we say look from XP with +momentum sub P yes they give me I h-bar + + align:start position:0% +momentum sub P yes they give me I h-bar + + + align:start position:0% +momentum sub P yes they give me I h-bar +Delta IJ but there will be I h-bar the + + align:start position:0% +Delta IJ but there will be I h-bar the + + + align:start position:0% +Delta IJ but there will be I h-bar the +first factor there will be an extra MP + + align:start position:0% +first factor there will be an extra MP + + + align:start position:0% +first factor there will be an extra MP +over MP plus m e so this contribution + + align:start position:0% +over MP plus m e so this contribution + + + align:start position:0% +over MP plus m e so this contribution +comes from the first term that only + + align:start position:0% +comes from the first term that only + + + align:start position:0% +comes from the first term that only +talks to the momentum of the proton + + align:start position:0% +talks to the momentum of the proton + + + align:start position:0% +talks to the momentum of the proton +doesn't talk to the momentum of the leg + + align:start position:0% +doesn't talk to the momentum of the leg + + + align:start position:0% +doesn't talk to the momentum of the leg +through and the second term for the + + align:start position:0% +through and the second term for the + + + align:start position:0% +through and the second term for the +coordinate of electron only talks to the + + align:start position:0% +coordinate of electron only talks to the + + + align:start position:0% +coordinate of electron only talks to the +momentum of + + align:start position:0% +momentum of + + + align:start position:0% +momentum of +the lectern and it does give you an I + + align:start position:0% +the lectern and it does give you an I + + + align:start position:0% +the lectern and it does give you an I +h-bar Delta IJ but this time will be + + align:start position:0% +h-bar Delta IJ but this time will be + + + align:start position:0% +h-bar Delta IJ but this time will be +with an M e / MP + M II and this factor + + align:start position:0% +with an M e / MP + M II and this factor + + + align:start position:0% +with an M e / MP + M II and this factor +is equal to 1 so yes we can box this + + align:start position:0% +is equal to 1 so yes we can box this + + + align:start position:0% +is equal to 1 so yes we can box this +this is a pair of quantum mechanical + + align:start position:0% +this is a pair of quantum mechanical + + + align:start position:0% +this is a pair of quantum mechanical +canonical variables they have the right + + align:start position:0% +canonical variables they have the right + + + align:start position:0% +canonical variables they have the right +commutator they have the right unit the + + align:start position:0% +commutator they have the right unit the + + + align:start position:0% +commutator they have the right unit the +right comity to write everything so next + + align:start position:0% +right comity to write everything so next + + + align:start position:0% +right comity to write everything so next +time when you see these you will say X + + align:start position:0% +time when you see these you will say X + + + align:start position:0% +time when you see these you will say X +with P you say X P with piece 1 XE with + + align:start position:0% +with P you say X P with piece 1 XE with + + + align:start position:0% +with P you say X P with piece 1 XE with +piece 1 and P + n - 1 yes it works + + align:start position:0% +piece 1 and P + n - 1 yes it works + + + align:start position:0% +piece 1 and P + n - 1 yes it works +you forget I h-bar Delta IJ was sort of + + align:start position:0% +you forget I h-bar Delta IJ was sort of + + + align:start position:0% +you forget I h-bar Delta IJ was sort of +clear that it will work try it up next + + align:start position:0% +clear that it will work try it up next + + + align:start position:0% +clear that it will work try it up next +we need the second pair of canonical + + align:start position:0% +we need the second pair of canonical + + + align:start position:0% +we need the second pair of canonical +variables so + + align:start position:0% + + + + align:start position:0% + +so for the second pair it's reasonable + + align:start position:0% +so for the second pair it's reasonable + + + align:start position:0% +so for the second pair it's reasonable +to use the X that he anticipated so + + align:start position:0% +to use the X that he anticipated so + + + align:start position:0% +to use the X that he anticipated so +we'll have a relative for Nik eggs and I + + align:start position:0% +we'll have a relative for Nik eggs and I + + + align:start position:0% +we'll have a relative for Nik eggs and I +don't know how I call it X relative or + + align:start position:0% +don't know how I call it X relative or + + + align:start position:0% +don't know how I call it X relative or +know just little X little X will be + + align:start position:0% +know just little X little X will be + + + align:start position:0% +know just little X little X will be +defined as X of the electron electron + + align:start position:0% +defined as X of the electron electron + + + align:start position:0% +defined as X of the electron electron +minus X of the probe this is natural we + + align:start position:0% +minus X of the probe this is natural we + + + align:start position:0% +minus X of the probe this is natural we +want a little X like that already at + + align:start position:0% +want a little X like that already at + + + align:start position:0% +want a little X like that already at +this point you could be paralyzed with + + align:start position:0% +this point you could be paralyzed with + + + align:start position:0% +this point you could be paralyzed with +fear something could have gone wrong at + + align:start position:0% +fear something could have gone wrong at + + + align:start position:0% +fear something could have gone wrong at +this moment imagine if this X doesn't + + align:start position:0% +this moment imagine if this X doesn't + + + align:start position:0% +this moment imagine if this X doesn't +compute with this dies then it's all a + + align:start position:0% +compute with this dies then it's all a + + + align:start position:0% +compute with this dies then it's all a +disaster because this should be electron + + align:start position:0% +disaster because this should be electron + + + align:start position:0% +disaster because this should be electron +and proton commute with each other + + align:start position:0% +and proton commute with each other + + + align:start position:0% +and proton commute with each other +action of written there not only those + + align:start position:0% +action of written there not only those + + + align:start position:0% +action of written there not only those +are the commutation relations everything + + align:start position:0% +are the commutation relations everything + + + align:start position:0% +are the commutation relations everything +else is 0 any X of electron with a + + align:start position:0% +else is 0 any X of electron with a + + + align:start position:0% +else is 0 any X of electron with a +momentum of a proton is 0 that's why + + align:start position:0% +momentum of a proton is 0 that's why + + + align:start position:0% +momentum of a proton is 0 that's why +there are two independent pairs of + + align:start position:0% +there are two independent pairs of + + + align:start position:0% +there are two independent pairs of +dynamical variables a week and three in + + align:start position:0% +dynamical variables a week and three in + + + align:start position:0% +dynamical variables a week and three in +better beam and this is an independent + + align:start position:0% +better beam and this is an independent + + + align:start position:0% +better beam and this is an independent +pair of canonical variables so it better + + align:start position:0% +pair of canonical variables so it better + + + align:start position:0% +pair of canonical variables so it better +be that these eggs and whatever P I'm + + align:start position:0% +be that these eggs and whatever P I'm + + + align:start position:0% +be that these eggs and whatever P I'm +going to define here commute with these + + align:start position:0% +going to define here commute with these + + + align:start position:0% +going to define here commute with these +guys and as far as this eggs happy lead + + align:start position:0% +guys and as far as this eggs happy lead + + + align:start position:0% +guys and as far as this eggs happy lead +works out because excess commute with + + align:start position:0% +works out because excess commute with + + + align:start position:0% +works out because excess commute with +any excess here so this little X + + align:start position:0% +any excess here so this little X + + + align:start position:0% +any excess here so this little X +definitely from this with a little egg + + align:start position:0% +definitely from this with a little egg + + + align:start position:0% +definitely from this with a little egg +but the father who commutes with P could + + align:start position:0% +but the father who commutes with P could + + + align:start position:0% +but the father who commutes with P could +have killed it but it doesn't because of + + align:start position:0% +have killed it but it doesn't because of + + + align:start position:0% +have killed it but it doesn't because of +the minus sign one of the company + + align:start position:0% +the minus sign one of the company + + + align:start position:0% +the minus sign one of the company +of the little eggs with a capital P + + align:start position:0% +of the little eggs with a capital P + + + align:start position:0% +of the little eggs with a capital P +would give for the lek Fernand IH bar + + align:start position:0% +would give for the lek Fernand IH bar + + + align:start position:0% +would give for the lek Fernand IH bar +and for the program and minus IH bar the + + align:start position:0% +and for the program and minus IH bar the + + + align:start position:0% +and for the program and minus IH bar the +answer so all is good so far so this is + + align:start position:0% +answer so all is good so far so this is + + + align:start position:0% +answer so all is good so far so this is +so far so good + + align:start position:0% +so far so good + + + align:start position:0% +so far so good +commutes with capital X and capital P so + + align:start position:0% +commutes with capital X and capital P so + + + align:start position:0% +commutes with capital X and capital P so +now we have here something and we could + + align:start position:0% +now we have here something and we could + + + align:start position:0% +now we have here something and we could +put a number alpha P e minus beta P the + + align:start position:0% +put a number alpha P e minus beta P the + + + align:start position:0% +put a number alpha P e minus beta P the +proto and we all know what alpha and + + align:start position:0% +proto and we all know what alpha and + + + align:start position:0% +proto and we all know what alpha and +beta are but now we can more or less be + + align:start position:0% +beta are but now we can more or less be + + + align:start position:0% +beta are but now we can more or less be +confident oh I need that this momentum + + align:start position:0% +confident oh I need that this momentum + + + align:start position:0% +confident oh I need that this momentum +with this X give me one IH bar so that + + align:start position:0% +with this X give me one IH bar so that + + + align:start position:0% +with this X give me one IH bar so that +would put the condition alpha and beta + + align:start position:0% +would put the condition alpha and beta + + + align:start position:0% +would put the condition alpha and beta +in fact the condition that X I with P + + align:start position:0% +in fact the condition that X I with P + + + align:start position:0% +in fact the condition that X I with P +bar J give you I h-bar Delta I J you can + + align:start position:0% +bar J give you I h-bar Delta I J you can + + + align:start position:0% +bar J give you I h-bar Delta I J you can +imagine what it is is that alpha plus + + align:start position:0% +imagine what it is is that alpha plus + + + align:start position:0% +imagine what it is is that alpha plus +beta is equal to 1 and the condition + + align:start position:0% +beta is equal to 1 and the condition + + + align:start position:0% +beta is equal to 1 and the condition +that this momentum commute with the + + align:start position:0% +that this momentum commute with the + + + align:start position:0% +that this momentum commute with the +center of mass position which it can + + align:start position:0% +center of mass position which it can + + + align:start position:0% +center of mass position which it can +fail to do so + + align:start position:0% + + + + align:start position:0% + +how what can I give well of alpha of the + + align:start position:0% +how what can I give well of alpha of the + + + align:start position:0% +how what can I give well of alpha of the +P of the letter goes with M e so it's + + align:start position:0% +P of the letter goes with M e so it's + + + align:start position:0% +P of the letter goes with M e so it's +something like alpha M e minus beta M P + + align:start position:0% +something like alpha M e minus beta M P + + + align:start position:0% +something like alpha M e minus beta M P +is equal to zero + + align:start position:0% +is equal to zero + + + align:start position:0% +is equal to zero +and please of this commutator should be + + align:start position:0% +and please of this commutator should be + + + align:start position:0% +and please of this commutator should be +zero please make sure you know how to do + + align:start position:0% +zero please make sure you know how to do + + + align:start position:0% +zero please make sure you know how to do +this we can get those conditions and + + align:start position:0% +this we can get those conditions and + + + align:start position:0% +this we can get those conditions and +though maybe a little fast for you to + + align:start position:0% +though maybe a little fast for you to + + + align:start position:0% +though maybe a little fast for you to +just follow it up + + align:start position:0% +just follow it up + + + align:start position:0% +just follow it up +and so at this moment we can solve for + + align:start position:0% +and so at this moment we can solve for + + + align:start position:0% +and so at this moment we can solve for +alpha beta two equations so alpha is + + align:start position:0% +alpha beta two equations so alpha is + + + align:start position:0% +alpha beta two equations so alpha is +equal to NP over m e+ MP and beta is + + align:start position:0% +equal to NP over m e+ MP and beta is + + + align:start position:0% +equal to NP over m e+ MP and beta is +equal to m e / n e + NP and we have a + + align:start position:0% +equal to m e / n e + NP and we have a + + + align:start position:0% +equal to m e / n e + NP and we have a +pair of canonical variables as well here + + align:start position:0% +pair of canonical variables as well here + + + align:start position:0% +pair of canonical variables as well here +therefore the relative coordinate and + + align:start position:0% +therefore the relative coordinate and + + + align:start position:0% +therefore the relative coordinate and +the relative momentum in some sensors + + align:start position:0% +the relative momentum in some sensors + + + align:start position:0% +the relative momentum in some sensors +useful to be fine too simple + + align:start position:0% +useful to be fine too simple + + + align:start position:0% +useful to be fine too simple +newse mass and the MP / MP + MP and the + + align:start position:0% +newse mass and the MP / MP + MP and the + + + align:start position:0% +newse mass and the MP / MP + MP and the +total mass which is an e + MP in the + + align:start position:0% +total mass which is an e + MP in the + + + align:start position:0% +total mass which is an e + MP in the +case of a heavy proton the reduce mass + + align:start position:0% +case of a heavy proton the reduce mass + + + align:start position:0% +case of a heavy proton the reduce mass +the product is heavy compared with + + align:start position:0% +the product is heavy compared with + + + align:start position:0% +the product is heavy compared with +electron you can ignore the electron + + align:start position:0% +electron you can ignore the electron + + + align:start position:0% +electron you can ignore the electron +here cancel an e and the reduced mass is + + align:start position:0% +here cancel an e and the reduced mass is + + + align:start position:0% +here cancel an e and the reduced mass is +called this so with in terms of the + + align:start position:0% +called this so with in terms of the + + + align:start position:0% +called this so with in terms of the +reduced mass F is equal to MU / n E and + + align:start position:0% +reduced mass F is equal to MU / n E and + + + align:start position:0% +reduced mass F is equal to MU / n E and +beta is mu / MP those are unit free + + align:start position:0% +beta is mu / MP those are unit free + + + align:start position:0% +beta is mu / MP those are unit free +concerts so summarizing the second pair + + align:start position:0% +concerts so summarizing the second pair + + + align:start position:0% +concerts so summarizing the second pair +of canonical variables are X D minus x e + + align:start position:0% +of canonical variables are X D minus x e + + + align:start position:0% +of canonical variables are X D minus x e +minus X P and P equals mu P e / m e + + align:start position:0% +minus X P and P equals mu P e / m e + + + align:start position:0% +minus X P and P equals mu P e / m e +minus P sub P / MP + + align:start position:0% +minus P sub P / MP + + + align:start position:0% +minus P sub P / MP +[Applause] + + align:start position:0% + + + + align:start position:0% + +all right so so last step that we're + + align:start position:0% +all right so so last step that we're + + + align:start position:0% +all right so so last step that we're +going to follow and after that we'll get + + align:start position:0% +going to follow and after that we'll get + + + align:start position:0% +going to follow and after that we'll get +the Hamiltonian and stop there we'll + + align:start position:0% +the Hamiltonian and stop there we'll + + + align:start position:0% +the Hamiltonian and stop there we'll +discuss solutions next time but though + + align:start position:0% +discuss solutions next time but though + + + align:start position:0% +discuss solutions next time but though +finally we have enough equations to + + align:start position:0% +finally we have enough equations to + + + align:start position:0% +finally we have enough equations to +solve for the momentum we have in the + + align:start position:0% +solve for the momentum we have in the + + + align:start position:0% +solve for the momentum we have in the +Hamiltonian in terms of the center of + + align:start position:0% +Hamiltonian in terms of the center of + + + align:start position:0% +Hamiltonian in terms of the center of +mass momentum and the relative momentum + + align:start position:0% +mass momentum and the relative momentum + + + align:start position:0% +mass momentum and the relative momentum +so from Equation star and double star + + align:start position:0% +so from Equation star and double star + + + align:start position:0% +so from Equation star and double star +here you can solve for this momentous of + + align:start position:0% +here you can solve for this momentous of + + + align:start position:0% +here you can solve for this momentous of +P of the proton will be equal to NP over + + align:start position:0% +P of the proton will be equal to NP over + + + align:start position:0% +P of the proton will be equal to NP over +m big momentum minus little momenta and + + align:start position:0% +m big momentum minus little momenta and + + + align:start position:0% +m big momentum minus little momenta and +P of the electron is an e over capital n + + align:start position:0% +P of the electron is an e over capital n + + + align:start position:0% +P of the electron is an e over capital n +big momentum plus little + + align:start position:0% + + + + align:start position:0% + +well one more equation that we have to + + align:start position:0% +well one more equation that we have to + + + align:start position:0% +well one more equation that we have to +write and that's the key to the + + align:start position:0% +write and that's the key to the + + + align:start position:0% +write and that's the key to the +simplicity of all what we've done at + + align:start position:0% +simplicity of all what we've done at + + + align:start position:0% +simplicity of all what we've done at +this moment we have a very good physical + + align:start position:0% +this moment we have a very good physical + + + align:start position:0% +this moment we have a very good physical +insight into what we've done but we want + + align:start position:0% +insight into what we've done but we want + + + align:start position:0% +insight into what we've done but we want +to see the math collaborate and the good + + align:start position:0% +to see the math collaborate and the good + + + align:start position:0% +to see the math collaborate and the good +physical insight has been that center of + + align:start position:0% +physical insight has been that center of + + + align:start position:0% +physical insight has been that center of +mass motion should be independent of the + + align:start position:0% +mass motion should be independent of the + + + align:start position:0% +mass motion should be independent of the +relative motion and we have the right X + + align:start position:0% +relative motion and we have the right X + + + align:start position:0% +relative motion and we have the right X +so the thing that we have to compute is + + align:start position:0% +so the thing that we have to compute is + + + align:start position:0% +so the thing that we have to compute is +the first two terms in the Hamiltonian P + + align:start position:0% +the first two terms in the Hamiltonian P + + + align:start position:0% +the first two terms in the Hamiltonian P +of the proton squared over 2m of the + + align:start position:0% +of the proton squared over 2m of the + + + align:start position:0% +of the proton squared over 2m of the +proton plus P of the electron squared + + align:start position:0% +proton plus P of the electron squared + + + align:start position:0% +proton plus P of the electron squared +over two months of the electron so I + + align:start position:0% +over two months of the electron so I + + + align:start position:0% +over two months of the electron so I +have 1 over 2m of the proton and 1/2 m + + align:start position:0% +have 1 over 2m of the proton and 1/2 m + + + align:start position:0% +have 1 over 2m of the proton and 1/2 m +of the proton over capital and P minus P + + align:start position:0% +of the proton over capital and P minus P + + + align:start position:0% +of the proton over capital and P minus P +and plus 1 over 2m of the electron is + + align:start position:0% +and plus 1 over 2m of the electron is + + + align:start position:0% +and plus 1 over 2m of the electron is +squared M of the electron over capital M + + align:start position:0% +squared M of the electron over capital M + + + align:start position:0% +squared M of the electron over capital M +big P plus little P and the plus and + + align:start position:0% +big P plus little P and the plus and + + + align:start position:0% +big P plus little P and the plus and +minus are extremely reassuring because + + align:start position:0% +minus are extremely reassuring because + + + align:start position:0% +minus are extremely reassuring because +the cross terms at couple the two are + + align:start position:0% +the cross terms at couple the two are + + + align:start position:0% +the cross terms at couple the two are +going to banish you can see the cross + + align:start position:0% +going to banish you can see the cross + + + align:start position:0% +going to banish you can see the cross +term with a minus sign and P will cancel + + align:start position:0% +term with a minus sign and P will cancel + + + align:start position:0% +term with a minus sign and P will cancel +we will they will cancel so at the end + + align:start position:0% +we will they will cancel so at the end + + + align:start position:0% +we will they will cancel so at the end +of this little calculation that takes a + + align:start position:0% +of this little calculation that takes a + + + align:start position:0% +of this little calculation that takes a +couple of lines you get one over to + + align:start position:0% +couple of lines you get one over to + + + align:start position:0% +couple of lines you get one over to +capital M total center of mass of this + + align:start position:0% +capital M total center of mass of this + + + align:start position:0% +capital M total center of mass of this +squared plus one over to you + + align:start position:0% +squared plus one over to you + + + align:start position:0% +squared plus one over to you +little momentum squared this is a + + align:start position:0% +little momentum squared this is a + + + align:start position:0% +little momentum squared this is a +kinetic operator and then you say great + + align:start position:0% +kinetic operator and then you say great + + + align:start position:0% +kinetic operator and then you say great +success the kinetic energy now has + + align:start position:0% +success the kinetic energy now has + + + align:start position:0% +success the kinetic energy now has +separated into a center of mass + + align:start position:0% +separated into a center of mass + + + align:start position:0% +separated into a center of mass +contribution and a relative confident + + align:start position:0% +contribution and a relative confident + + + align:start position:0% +contribution and a relative confident +this will allow us now with a little + + align:start position:0% +this will allow us now with a little + + + align:start position:0% +this will allow us now with a little +step separated total Schrodinger + + align:start position:0% +step separated total Schrodinger + + + align:start position:0% +step separated total Schrodinger +equation into center of mass motion and + + align:start position:0% +equation into center of mass motion and + + + align:start position:0% +equation into center of mass motion and +relative motion and the relative motion + + align:start position:0% +relative motion and the relative motion + + + align:start position:0% +relative motion and the relative motion +will have the center of edge so we'll do + + align:start position:0% +will have the center of edge so we'll do + + + align:start position:0% +will have the center of edge so we'll do +the punchline next \ No newline at end of file diff --git a/8PScXRfu2po.txt b/8PScXRfu2po.txt new file mode 100644 index 0000000000000000000000000000000000000000..4636950186637e0146b169a82775f980bf79161d --- /dev/null +++ b/8PScXRfu2po.txt @@ -0,0 +1,3466 @@ +SPEAKER: The following content +is provided under a Creative + +Commons license. + +Your support will help MIT +OpenCourseWare continue to + +offer high quality educational +resources for free. + +To make a donation, or to view +additional material from + +hundreds of MIT courses, visit +MIT OpenCourseWare at + +ocw.mit.edu. + +PROFESSOR: OK I want to review +a little bit what we said + +about detection at the end of +last hour, last hour and a + +half, because we were going +through it relatively quickly. + +Detection is a very +funny subject. + +Particularly the way that we +do it here because we go + +through a bunch of very, +very simple steps. + +Everything looks trivial-- + +I hope it looks trivial-- as +we go, at least after you + +think about it for awhile, and +you work with it for awhile, + +you will come back and look at +it and you will say, "yes, in + +fact that is trivial." Nothing +when you look at it for the + +first time is trivial. + +And the kind of detection +problems that we're + +interested in is-- + +to start out with-- we want to +look just at binary detection. + +We're sending a binary signal, +it's going to go through some + +signal encoder, which is the +kind of channel encoder we've + +been thinking about. + +It's going to go through a +baseband modulator, a baseband + +to passband modulator. + +It's going to have white +Gaussian noise, or some kind + +of noise, added to it. + +It's going to come out +the other end. + +We come back from passband +to baseband. + +We then go through a baseband +demodulator. + +We then sample at that point. + +And, the point is, when you're +all done with all of that, + +what you've done is you've +started out sending either + +plus a or minus a as a one- +dimensional numerical signal. + +And when you're all through, +there's some one- dimensional + +number that comes out, v. And +on the basis of that one- + +dimensional number, v, you're +supposed to guess whether the + +output is zero or one. + +Now, one of the things that +we're doing right now is we're + +simplifying the problem in the +sense that we're not looking + +at a sequence of inputs coming +in, and we're not looking at a + +sequence of outputs +coming out. + +We're only looking at a single +input coming in. + +In other words, you build this +piece of communication + +equipment, you get it all tuned +up, you get it into + +steady state. + +You send one bit. + +You receive something. + +You try to guess at the +receiver, what was sent. + +And at that point you tear the +whole thing down and you wait + +a year until you've set +it up perfectly again. + +You send another bit. + +And we're not going to worry at +all about what happens with + +the sequence, we're only +going to worry about + +this one shot problem. + +You sort of have some kind of +clue that if you send the + +whole sequence of bits, in a +system like this, and you + +don't have intersymbol +interference, and the noise is + +white, so it's sort of +independent from time to time. + +You sort of have a clue that +you're going to get the same + +answer whether you send the +sequence of data or whether + +you just send a single bit. + +And we're going to show later +that that, in fact, is true. + +But for the time being we want +to understand what's going on, + +and to understand what's going +on we take this simplest + +possible case where there's +only one bit that's being + +transmitted. + +It's the question, "Are we going +to destroy ourselves in + +the next five years or not?" And +this question is important + +to most of us, and at the output +we find out, in fact, + +whether we're going to destroy +ourselves or not. + +So it's one bit, but it's +one important bit. + +OK, why are we doing +things this way? + +Want to tell you a little story +about the first time I + +really talked to +Claude Shannon. + +I was a young member of the +faculty at that time, and I + +was working on a problem +which I thought was + +really a neat problem. + +It was interesting +theoretically. + +It was important practically. + +And I thought, "gee, I finally +have something I can go to + +this great man and talk to him +about." So I screwed up my + +courage for about two days. + +Finally I saw his door open and +him sitting there, so I + +went in and started to tell +him about this problem. + +He's a very kind person and he +listened very patiently. + +And after about 15 minutes +he said, "My god! + +I'm just sort of lost +with all of this. + +There's so much stuff going +on in this problem. + +Can't we simplify it a little +bit by throwing out this kind + +of practical constraint you've +put on it?" I said, "yeah, I + +guess so." So we threw that +out and the we went on for + +awhile later, and then he +said, "My god, I'm still + +terribly confused about +this whole thing. + +Why don't we simplify it +in some other way?" + +And this went on for +about an hour. + +As I say, he was a +very patient guy. + +And at the end of an hour I was +getting really depressed. + +Because here was this beautiful +problem that I + +thought was going to make me +famous, give me tenure, do all + +these neat things. + +And here he'd reduced +the thing to a + +totally trivial toy problem. + +And we looked at it. + +And we said, yes this is +a trivial toy problem. + +This is the answer. + +The problem is solved. + +But so what? + +And then he suggested putting +some of those + +constraints back in again. + +And as we started putting the +constraints back in, one- by- + +one, we saw that each time we +put a new constraint in-- + +since we understood the problem +and its simplest + +form-- putting the constraint +in, it was still simple. + +And by the time we built the +whole thing back up again, it + +was clear what the answer was. + +OK, in other words, what theory +means is really solving + +these toy problems. + +And solving the toy +problems first. + +And in terms of practice, some +people think the most + +practical thing is +to be practical. + +And the whole point of this +course, and this particular + +subject of detection is a +wonderful example of this, the + +most practical thing is +to be theoretical. + +I mean, you need to add practice +to the theory, but + +the way you do things is you +start with a theory-- which + +means you start with the toy +problems, you build up from + +those toy problems, and after +you build up for awhile, + +understanding what the practical +problem is also-- + +you then understand +how to deal with + +the practical problem. + +And the practical engineer who +doesn't have any of that + +fundamental knowledge about +how to deal with these + +problems is always submerged +in a sea of complexity. + +Always doing simulations of +something that he doesn't, he + +or she doesn't understand. + +Always trying to interpret +something from it, but with + +just too many things going on +to have any idea of what it + +really means. + +Ok, so that's why we're making +this trivial assumption here. + +We're only putting one bit in. + +We're ignoring what +happens all the + +way through the system. + +We only get one number out. + +We're going to assume that this +one number here is either + +plus or minus a, plus +the Gaussian + +random noise variable. + +And we're not quite sure why +it's going to be plus or minus + +a, plus a Gaussian noise random +variable, but we're + +going to assume that +for the time being. + +OK? + +So the detector observes the +sample values of the random + +variable for which this is the +sample value, and then guesses + +what the value of this random +variable, h, which is what we + +call the input now. + +Because we view it from the +standpoint of the detector-- + +the detector has two possible +hypotheses-- + +one is that a zero was +sent, and the other + +that a one was sent. + +And on the basis of this +observation, you take first + +the hypothesis zero and you +say, "Is this a reasonable + +hypothesis?" Then you look at +the hypothesis one, say, "Is + +this a reasonable hypothesis?" +And then you guess whether you + +think zero was more likely or +one is more likely, given this + +observation that you've had. + +So what they detector has, +at this point, is a full + +statistical characterization +of the entire problem. + +Mainly you have a model +of the problem. + +You understand every probability +in the universe + +that might have any +effect on this. + +And what might have any +effect on this-- + +as far as the way we've +set up the problem-- + +is only the question of what +are the probabilities that + +you're going to send +one or the other of + +these signals here? + +And conditional on each +of these, what are the + +probabilities of this +random variable + +appearing at the output? + +Because you have to base your +decision only on this. + +So all of the probabilities +only give you + +this one simple thing. + +Hypothesis testing, decision +making, decoding, all mean the + +same thing. + +They mean exactly +the same thing. + +And they're just done +by different people. + +OK, so what that says is we're +assuming the detector uses a + +known probability model. + +And in designing the detector, +you know what that + +probability model is. + +It might not be the right +probability model, and one of + +the things that many people +interested in detection study + +is the question of when you +think the probability model is + +one thing and it's actually +something else, how well does + +the detection work? + +It's a little like the +Lempel-Ziv algorithm that we + +studied earlier for doing +source coding. + +Which is, how do you do source +coding when you don't know + +what the probabilities are? + +And we found the best way to +study that, of course, was to + +first find out how to do source +encoding when you did + +know what the probabilities +were. + +So we're doing the +same thing here. + +We assume the detector is +designed to maximize the + +probability of guessing +correctly. + +In other words, it's trying +to minimize the + +probability of error. + +We call that a MAP detector-- +maximum a posteriori + +probability decoding. + +You can try to do +other things. + +You can say that there's a cost +of one kind of error, and + +there's another cost of +another kind of error. + +I mean, if you're doing medical +testing or something. + +If you guess wrong in one way, +you tell the patient there's + +nothing wrong with them, the +patient goes out, drops dead + +the next day. + +And you don't care about that, +of course, but you care about + +the fact that the patient is +going to sue the hospital for + +100 million dollars and you're +going to lose your + +job because of it. + +So there's a big cost to +guessing wrong in that way. + +But for now, we're not going +to bother about the costs. + +One of the things that you'll +see when we get all done is + +that putting in cost +doesn't make the + +problem any harder, really. + +You really wind up with the +same kind of problem. + +OK, so h is the random +variable that will be + +detected, and v is the +random variable + +that's going to be observed. + +The experiment is performed. + +Some sample value of v is +observed, and some sample + +value of the hypothesis +has actually happened. + +In other words, what has +happened is you prepared the + +whole system. + +Then at the input end to the +whole system, the input to the + +channel, somebody has chosen +a one or a zero without the + +knowledge of the receiver. + +That one or zero has been sent +through this whole system, the + +receiver has observed some +output, v, so in fact we're + +now dealing with the +sample values of + +two different things. + +The sample value of the input, +which is h, the sample value + +of the output, which is v, and +in terms of the sample value + +of the output, we're trying to +guess what the sample value of + +the input is. + +OK, an error then occurs if, +after the output chooses a + +particular hypothesis as its +guess, and that hypothesis, + +then, is a function of +what it receives. + +In other words, after you +receive something, what the + +detector has to do is somehow +map what gets received, which + +is some number, into +either zero or one. + +It's like what a +Quantizer does. + +Mainly, it maps the whole +region into two + +different sub- regions. + +Some things are mapped into +zero, Some things + +are mapped into one. + +This H bar then becomes a random +variable, but is a + +random variable that is a +function of what's received. + +So we have one random variable, +H, which is what + +actually happened. + +There's another random variable, +H hat, which is what + +the detector guesses +will happen. + +This is an unusual random +variable, because it's not + +determined ahead of time. + +It's determined only in terms +of what you decide your + +detection rule is going to be. + +This is a random variable that +you have some control over. + +These other random variables +you have no + +control over at all. + +So that's the random variable +we're going to choose. + +And, in fact, what we're going +to do is we're going to say + +what we want to do is this MAP +decoding, maximum a posteriori + +probability decoding, where +we're trying to minimize the + +probability of screwing up. + +And we don't care whether we +make an error of one kind or + +make an error of +the other kind. + +OK, is that formulation of the +problem crystal clear? + +Anybody have any questions +about it? + +I mean, the easiest way to get +screwed up with detection is + +at a certain point to be going +through, studying a detection + +problem, and then you +suddenly realize you + +don't understand what-- + +you don't understand what the +whole problem is about. + +OK, let's assume we do know +what the problem is, then. + +In principle it's simple. + +Given a particular observed +value, what we're going to do + +is we're going to calculate +the-- what we call the a + +posteriori probability, the +probability given that + +particular sample value +of the observation-- + +we're going to calculate the +probability that what went + +into the system is a zero +and what went into + +the system is a one. + +OK? + +This is the probability that +j is the sample value of H, + +conditional on what +we observed. + +OK, if you can calculate this +quantity, it tells you if I + +decide that-- + +if I guess that H is equal to +j-- this in fact tells me that + +this is the probability +that guess is correct. + +And if this is the probability +that guess is correct, and I + +want to maximize my probability +of guessing + +correctly, what do I do? + +Well, what I do is my MAP +rule is arg max of this + +probability. + +And "arg max" means instead +of trying to maximize this + +instead of trying to maximize +this quantity over something, + +what we're doing is trying to +find the value of j, which + +maximizes this. + +In other words, we calculate +this for each value of j, and + +then we picked the j for which +this quantity is largest. + +In other words, we maximize this +but we're not interested + +in the maximum value of +it at this point. + +We're interested in it later +because that's the probability + +that we're choosing correctly. + +What we're interested in, for +now, is what is the hypothesis + +that we're going to guess. + +OK? + +So this probability of being +correct is going to the this + +probability for this +maximal j. + +And when we average over v we +get the overall probability of + +being correct. + +There's a theorem which is +stated in the notes, which is + +one of the more trivial theorems +you can think of, + +which says that if you do the +best thing for every sample + +point you, in fact, have done +the best thing on average. + +I think that's pretty clear. + +If you, well I mean you can read +it if you want to form a + +proof, but if you do the best +thing all the time, then it's + +the overall best thing. + +OK, so that's the general +idea of detection. + +And in doing this we have to +be able to calculate these + +probabilities, so that's +the only constraint. + +These are probabilities, which +means that this set of + +hypothesis is discrete. + +If you have an uncountable +infinite number of hypotheses, + +at that point you're dealing +with an estimation problem. + +Because you don't have any +chance in hell of getting the + +right answer, exactly +the right answer. + +And therefore you have to +have some criterion for + +how close you are. + +And that's what's important +in estimation. + +And here what's important is +really, do we guess right or + +don't we guess right. + +And we don't, we don't care. + +There aren't any near +misses here. + +You either get it on the +nose or you don't. + +OK, so we want to study +binary detection now + +to start off with. + +We want to trivialize the +problem because even that + +problem we just stated +is too hard. + +So we're going to trivialize +it in two ways. + +We're going to assume that there +are only two hypotheses. + +That it's a binary detection +problem. + +And we're also going to assume +that it's Gaussian noise. + +And that will make it sort of +transparent what's happening. + +So H takes the values +zero or one. + +And we'll call the probabilities +with which it + +takes those values +P zero and P one. + +These are called a priori +probabilities. + +In other words, these are the +probabilities that the + +hypothesis takes to value zero +or one before seeing any + +observation. + +And the probabilities after you +see the observation are + +called a posteriori +probabilities. + +In other words, probabilities +after the observation and the + +probabilities before +the observation. + +Up until about 1950 +statisticians used to argue + +terribly about whether it was +valid to assume a priori + +probabilities. + +And as you can see by thinking +about it a little bit, the + +problem they were facing was +they couldn't separate the + +problem of choosing a +mathematical model and + +analyzing it from the problem +of figuring out whether the + +model was valid or not. + +And at that point people +studying in that area had not + +gotten to the point where they +could say, "Well, maybe I + +ought to analyze the problem for +different models, and then + +after I understand what happens +for different models I + +then ought to go back because +I'll know what's important to + +find out in the real problem." +But up until that time, there + +was just fighting +among everyone. + +Bayes was the person who decided +you really ought to + +assume that there's a +model to start with. + +And he developed most +of detection + +theory at an early time. + +And people used to think that +Bayes was a terrible fraud. + +Because in fact he was using +models of the problem rather + +than nothing. + +But anyway, that's +where we were. + +We're also going to assume that, +after we get all through + +with modulation and +demodulation, and we really + +want to look at a general +problem here. + +There's one discrete random +variable, H, one analog random + +variable, which has a +probability density, v, what + +we want to assume is that +there's a probability density + +that we know, which is the +probability density of the + +observation conditional +on the hypothesis. + +We're assuming that we know +this, and we know this-- + +we call these things +likelihoods-- + +and in most communication +problems anyway, it's far + +easier to get your hand on these +likelihoods than it is + +to get your hand the a +posteriori probabilities, + +which you're really +interested in. + +So we find these likelihoods, +we can find the marginal + +density of the observation. + +Which is just the +weighted sum. + +The probability that the +hypothesis is zero times a + +conditional probability of the +observation and so forth. + +So we're going to assume that +those densities exist. + +We're going to assume +that we know them. + +And then with a great feat of +probability theory, we say the + +a posteriori probability is +equal to the a priori + +probability times the likelihood +divided by the + +marginal probability of v. OK? + +What was the first thing you +learn in probability when you + +started studying random +variables? + +It was probably this formula, +which says when you have a + +joint density of two random +variables you can + +write it in two ways. + +You can either write, "density +of one times density of two + +conditional and one is equal +to the density of two times + +density of one conditional in +two." And then you think about + +it a little bit and you say, +"A ha!" It doesn't matter + +whether the first one is the +density or whether it's the + +probability. + +You can deal with it +in the same way. + +And you get this formula, +which I hope is + +not unusual to you. + +OK, so our MAP decision rule +then, our MAP decision rule, + +remember, is to pick the more, +is to find the a posteriori + +probability which is +most probable. + +Because that is the probability +of being correct. + +So, in fact, if this probability +is bigger than + +this probability, this is the a +posteriori probability that + +H is equal to zero. + +This is the a posteriori +probability that + +H is equal to one. + +So we're just going to compare +those two and pick the larger. + +And if this one is larger than +this one, we pick our choice + +equal zero. + +And if it's smaller, we pick +our choice equal to one. + +So this is what MAP +detection is. + +Why did I make this greater +than or equal + +and this less than? + +Well, if we have densities, +it doesn't often make any + +difference. + +Strangely enough, it does +sometimes make a difference. + +Because sometimes you can have +a density, and the densities + +are the same for both of +these likelihoods. + +And you can find situations +where it's important. + +But when the two probabilities +are the same, the probability + +of being correct is the same in +both cases, so it doesn't + +make any difference what +you do when you + +have a quality here. + +And therefore we've just +made a decision. + +We've said, OK, what we're going +to do is whenever this + +is equal to this, we're +going to choose zero. + +If you prefer choosing +one, be my guest. + +All of your MAP error +probabilities will + +be exactly the same. + +Nothing will change. + +It just is easier to do the +same thing all the time. + +OK, well then we look at this +formula, and we say, "Well, I + +can simplify this a little +bit." If I take this + +likelihood and move it over to +this side, and if I take this + +marginal density and move it +over to this side, and if I + +take p zero and move it over +to this side, then the + +marginal densities cancel out. + +They had nothing to do +with the problem. + +And I wind up with a ratio +of the likelihoods. + +And what do you think +the ratio of the + +likelihoods is called? + +Somebody got the smart +idea of calling that + +a likelihood ratio. + +Somehow the people in statistics +were much better at + +generating notation than the +people in communication theory + +who have done just an abominable +job of choosing + +notation for things. + +But anyway, they call this +a likelihood ratio. + +And the rule then becomes: if +the likelihood ratio is + +greater than or equal to +the ratio of p1 to + +p0, we choose zero. + +And if it's less, +we choose one. + +And we call this ratio +the threshold. + +So in fact what this says is +binary MAP tests are always + +threshold tests. + +And by a threshold test I mean +finds the likelihood ratio, + +compare the likelihood ratio +with the threshold-- the + +threshold in fact is this +ratio of a priori + +probabilities-- + +and at that point you +have actually + +achieved the MAP test. + +In other words, you have done +something which actually, for + +real, minimizes the probability +of error. + +Maximizes the probability +of being correct. + +Well because of that, this thing +here, this likelihood + +ratio, is called a sufficient +statistic. + +And it's called a sufficient +statistic because you can do + +math decoding just by +knowing this number. + +OK? + +In other words, it says you can +you can calculate these + +likelihoods. + +You can find the ratio of +them-- which is this + +likelihood ratio-- and after you +know the likelihood ratio, + +you don't have to worry about +these likelihoods anymore. + +This is the only thing relevant +to the problem. + +Now this doesn't seem to be a +huge saving, because here + +we're dealing with two real +numbers-- well here we've + +reduced it to one real number-- +which is something. + +When we start dealing with +vectors, when we start dealing + +with wave forms, this is +really a big thing. + +Because what you're +doing is reducing + +the vectors to numbers. + +And when you reduce accountibly +infinite + +dimensional vector to a number, + +that's a big advantage. + +It also, in terms of the +communication problems we're + +facing, breaks up a detector +into two pieces in an + +interesting way. + +Mainly it says there are things +you do with the wave + +form in order to calculate what +this likelihood ratio is, + +and then after you find the +likelihood ratio you just + +forget about what the wave +form was and you + +deal only with that. + +What we're going to find out +is in this problem we were + +looking at here-- + +we're going to find out +later when we look + +at the vector problem-- + +in fact this thing here is in +fact the likelihood ratio if + +you make an observation out +at this point here. + +In other words, right at the +front end of the receiver, + +that's where you have all +the information you + +can possibly have. + +If you calculate likelihood +ratios at that point what + +you're going to do is to find +the likelihood ratio you're + +going to go through all this +stuff right here and wind up + +with that which is work which +is proportional to the + +likelihood ratio right here. + +OK, so one of the things we're +doing right now is we're not + +looking at that problem. + +We're only looking at the +simpler problem, assuming a + +one dimensional problem. + +But the reason we're looking +at it is that later we're + +going to show that this is, in +fact, the solution to the more + +general problem. + +Which was Shannon's idea +in the first place. + +Of, how do you solve the trivial +problem first and then + +see what the complicated +problem is. + +OK, so that's what we're trying +to do, summarized here + +for any binary detection problem +where the observation + +has a sample value of +a random something. + +Namely, a random vector, a +random process, a random + +variable, a complex variable, +a complex anything. + +Anything whatsoever, so long +as you can assign a + +probability density to it. + +You calculate the likelihood +ratio, which is this ratio + +here, so long as you have then +cities even talk about. + +The MAP rule is to compare this +likelihood ratio with the + +threshold data-- which is just +the ratio of the a priori + +probabilities-- + +if this is greater +than or equal to + +that, you choose zero. + +Otherwise you choose one. + +The MAP rule, as I said before, +partitions this + +observation space +into two pieces. + +Into two segments. + +And one of those pieces +gets mapped into zero. + +One of the pieces gets +mapped into one. + +It's exactly like a +binary quanitizer. + +Except the rule you use to +choose the the quantization + +regions is different. + +But a quanitizer maps a space +into a finite set of regions. + +And this detection rule does +exactly the same thing. + +And since the beginning of +information theory people have + +been puzzling over how to make +use of the correspondence + +between quanitization on one +hand and detection on the + +other hand. + +And there are some +correspondences but they + +aren't all that good +most of the time. + +OK, so you get an error when +the actual hypothesis that + +occurred, namely the bit that +got sent was i and if the + +observation landed in +the other subset. + +We know that the MAP rule +minimizes the error + +probability. + +So you have a rule which you +can use for all binary + +detection problems so long +as you have the density. + +And if you don't have a density +you can generalize it + +without too much trouble. + +OK, so we want to look at the +problem in Gaussian noise. + +In particular we want to +look at it for 2PAM. + +In other words for a standard +PAM system, where zero gets + +mapped into plus a and one +gets mapped into minus a. + +This is often called antipodal +signaling because you're + +sending a plus something +and a minus something. + +They are at opposite ends +of the spectrum. + +You push them as far away as you +can, because as you push + +them further and further +away it requires + +more and more energy. + +So you use the energy +you have. + +You get them as far apart as you +can, and you hope that's + +going to help you. + +And we'll see that +it does help you. + +OK, so what you receive then, +we'll assume, is either plus + +or minus a-- + +depending on which hypothesis +occured-- + +plus a Gaussian random +variable. + +And here's where the notation +of communication theorists + +rears its ugly head. + +We call the variance of this +random variable n 0 over 2. + +I would prefer to call +it sigma squared but + +unfortunately you can't +fight city hall on + +something like this. + +And everybody talks about +n 0 and n 0 over 2. + +And you got to get used to it. + +So here's where we're starting +to get used to it. + +So that's the variance of this +noise random variable. + +OK, we're only going to send one +binary digit, H, so this + +is the only, this is the sole +problem we have to deal with. + +We've made a binary choice. + +Added one Gaussian random +variable to it. + +You observe the sum, +and you guess. + +So what are these likelihoods +in this case? + +Well, the likelihood if H is +equal zero, in other words if + +you're sending a plus a, the +likelihood is just a Gaussian + +density shifted over by a. + +And if you're sending, on +the other hand, a one-- + +which means you're sending minus +a-- you have a Gaussian + +density shifted over +the other way. + +Let me show you a +picture of that. + +We'll come back to analyze more +things about the picture + +in a little bit, so don't +worry about most of the + +picture at this point. + +OK, this is the likelihood +probability density of the + +output given that +you sent a zero. + +Mainly that you sent plus a. + +So we have a Gaussian density-- +this bell shaped + +curve-- centered +around plus a. + +If you sent a one, you're +sending minus a-- one gets + +mapped into minus a-- and you +have the same bell shaped + +curve centered around minus a. + +If you receive any particular +value of v, mainly suppose you + +receive the value of v here, +you calculate these two + +likelihoods. + +One of them is this. + +One of them is that. + +You compare them, the ratio with +the threshold, and you + +make your choice. + +OK, so let's go back to do it. + +To do the arithmetic. + +Here are the two likelihoods. + +You take the ratio of +these two things. + +When you take the ratio +of them, what happens? + +And this sort of always +happens in + +these Gaussian problems. + +These terms cancel out. + +Well it always happens in these + +additive Gaussian problems. + +These terms cancel out. + +You take a ratio of +two exponents. + +You just get the difference. + +So the likelihood ratio-- +this divided by this-- + +is then e to the minus v minus +a squared over n0. + +and v plus a squared over n0. + +OK? + +Because normally the Gaussian +density is something divided + +by two sigma squared, and sigma +squared here is n0 over + +2, so the 2's cancel out. + +One nice thing about the +notation anyway, you get rid + +of one factor of two in it. + +Well so you have this +minus this. + +When you take the difference +of these two things the v + +squareds cancel out. + +Because one of these things is +in the numerator, the other + +one was in the denominator. + +So you have this term +comes through as is. + +This is-- + +you're dividing by this-- + +so when you multiply this +turns into a plus sign. + +So the v squared here cancels +out with the v squared here. + +The a squared here cancels out +with the a squared here. + +And it's only the inner product +term that survives + +this whole thing. + +And here you have plus 2va. + +Here you have plus 2va. + +So you wind up with e to +the 4av divided by n0. + +Which is very nice, because +what it says is this + +likelihood, which is what +determines everything in the + +world, is just a scalar in +multiple of the observation. + +And that that's going to +simplify things a fair amount. + +It's why that picture comes +out as simply is it does. + +OK, so to do a little more +of the arithmetic. + +This is the likelihood here, +e to the 4av over n0. + +So our rule is you compare +this likelihood to the + +threshold-- which is p1 over +p0, which we call eta-- + +and you look at that for awhile +and you say, "Gee, this + +is going to be much easier +to deal with. + +Instead of looking at the +likelihood ratio, I look at + +the log likelihood ratio." + +And people who deal with +Gaussian problems a lot, you + +never hear them talk about +likelihood ratios, you always + +hear them talk about log +likelihood ratios. + +And you can find one from the +other, so either one is + +equally good. + +In other words, the log +likelihood ratio is a + +sufficient statistic, because +you can calculate the + +likelihood ratio from it. + +So this is a sufficient +statistic. + +It's equal to 4av over n0. + +And when this is greater than +or equal the log of the + +threshold, you go this way. + +When it's less than, +you go this way. + +So when you then multiply by n0 +over 4a, your decision rule + +is you just look at +the observation. + +You compare it with n0 times +log of eta divided by 4a. + +And at this point we can go back +to this picture and sort + +of sort out what all +of it means. + +Because this point here +is now the threshold. + +It's n0 times log of +eta divided 4eta. + +By 4a. + +That's what we said the +threshold had to be. + +So we have these two Gaussian +curves now. + +Why do we have to go back and +look at these Gaussian curves? + +I told you that once we +calculated the likelihood + +ratio we could forget +about the curves. + +So why do I want to put +the curves back in? + +Well because I want to calculate +the probability of + +error at this point. + +OK? + +And it's easier to calculate the +probability of error if, + +in fact, I draw curve for +myself and I look at + +what's going on. + +So here's the threshold. + +Here's the density when H equals +one is the correct + +hypothesis. + +The probability of error is the +probability that when I + +send one, the observation is +going to be a random variable + +with this probability density +and if it's a wild case, and I + +got an enormous value of noise, +positive noise, the + +noise is going to push me over +that threshold there and I'm + +going to make a mistake. + +So, in fact, the probability +of error-- conditional on + +sending one-- + +is just this probability of that +little space in there. + +OK? + +Which is the probability that +I'm going to say that zero + +occurred when, in fact, +one occurred. + +So that's my probability of +error when one occurs. + +What's the probability of +error when zero occurs? + +Well it's the same analysis. + +When zero occurs-- + +mainly when the correct +hypothesis is zero-- + +the output, v, follows this +probability density here. + +And I'm going to screw up if +the noise carries me beyond + +this point here. + +So you can see what the +threshold is doing now. + +I mean, when you choose a +threshold which is positive it + +makes it much harder to screw +up when you send a minus a. + +It makes it much easier +to screw up when + +you send a plus a. + +But you see that's what we +wanted to do, because the + +threshold was positive in this +case, because p1 was so much + +larger than p0. + +And because p1 is so much +larger than p0-- + +p1 happens almost +all the time-- + +and therefore you would normally +almost choose p1 + +without looking at v. Which says +you want to push it over + +that way a little bit. + +OK, when you calculate this +probability of error, it's the + +probability of the tail of a +Gaussian random variable. + +So you define this tail +variable, q of x, is the + +complimentary distribution +function of a + +normal random variable. + +It's the integral from x to +infinity of one over the + +square root of 2pi, e to the +minus c squared over 2. + +I guess this would make better +sense if this were a z-- + +one and-- + +oh, no. + +No, I did it right +the first time. + +That's an x, because x is the +limit in there, you see. + +So I'm calculating all of the +probability density that's off + +to the right of x. + +And the probability of error +when H is equal to one is this + +probability-- which looks like +it's the tail on the negative + +side but if you think about +it a little bit, since the + +Gaussian curve is symmetric, you +can also look at it as a q + +function where now when you have +this is equal to zero, + +this corresponds to changing +this plus to a minus here and + +that's the only change. + +OK, so this looks a +little ugly and it + +looks a little strange. + +I mean you can sort +of interpret + +this part of it here-- + +I can interpret this +part if I'm using + +maximum likelihood decoding-- + +maximum likelihood is mapped +decoding where the threshold + +is equal to one. + +In other words, it's where +you're assuming that the + +hypothesis is equally likely to +be zero or one-- a priori-- + +which is a good assumption +almost always in communication + +because we work very hard in +doing source coding to make + +those binary digits equally +likely zero or one. + +And there are other reasons +for choosing maximum + +likelihood. + +If you don't know anything about +the probabilities it's a + +good assumption in a sort +of a max/min sense. + +It sort of limits how much you +can screw up by having the + +wrong probability, so it's a +very robust choice also. + +OK, but now this, we're taking +the ratio of a with the square + +root of n0. + +Well the square root of n0 over +2 is really the standard + +deviation of the noise. + +So what we're doing is comparing +the amount of input + +we've put in with the standard +deviation of the noise. + +Now does that make any sense? + +The probability of error +depends on that ratio? + +Well yeah, it makes a +whole lot of sense. + +Because if, for example, I +wanted to look at this problem + +in a different scaling +system-- + +if this is volts and I want to +look at it in milli-volts-- + +I'm going to divide a by, I'm +going to multiply a by 1000. + +I'm going to multiply the +standard deviation of the + +noise by 1000. + +Because one of the things we +always do here-- the way we + +choose n0 over 2-- + +n0 over 2 is sort of a +meaningless quantity. + +It's the noise energy in one +degree of freedom in the + +scaling reference that we're +using for the data. + +OK? + +And that's the only definition +you can come up with that + +makes any sense. + +I mean you scale the data in +whatever way you please, and + +when we've gone from baseband +to passband, we in fact have + +multiplied the energy in the +input by a factor of two. + +And therefore, because of +that, we're going to-- + +n0 at passband is going to be a +square root of 2 bigger than + +it is at baseband. + +If you don't like that, +live with it. + +That's the way it is. + +Nobody will change n0, +no matter who wants + +them to change it. + +OK, so this term make sense. + +It's the ratio of the signal +amplitude to the standard + +deviation of the noise. + +And that should be the only way +that the signal amplitude + +or the standard deviation of the +noise enters in, because + +it's really the ratio that +has to be important. + +Why this crazy term? + +Well if you look at the curve +you can sort of see why it is. + +The threshold test is comparing +the likelihood ratio + +of this curve with +the likelihood + +ratio of this curve. + +What's going to happen as +a gets very, very large? + +You move a out, and the thing +that's happening then is this + +curve-- which is now coming down +in a modest way here-- if + +you move a way out here, you're +going to have almost + +nothing there. + +And it's going to be going +down very fast. + +It's going to be going +down very fast + +relative to its magnitude. + +In other words the bigger +a gets, the bigger this + +difference is going to be +for any given threshold. + +And that's why you get a over +square root of n0 here. + +And here you get exactly +the opposite thing. + +That's because for a given +threshold, as this signal to + +noise ratio gets bigger, this +threshold term becomes almost + +totally unimportant. + +I mean you get so much +information out of the reading + +you're making, because it's +so reliable, that having a + +threshold is almost completely +irrelevant. + +And therefore you can sort +of forget about it. + +If a is very large, this +term is zilch. + +OK? + +So if you want to have reliable +communication and you + +use a large amount of single +noise ratio to get it, that's + +another reason for forgetting +about whether the threshold is + +one or something else. + +And we would certainly like to +deal with problems where the + +threshold is equal to one +because most people who + +remember q of a signal +to noise ratio. + +I don't know anybody who can +remember this formula. + +I'm sure there's some people, +but I don't think anybody who + +works in the communication +field ever thinks + +about this at all. + +Except the first time they +derive it and the say, "Oh, + +that's very nice." And then they +promptly forget about it. + +The only reason I think +about it more is I + +teach the course sometimes. + +Otherwise I would forget +about it, too. + +OK, which is what this says. + +For communication we assume +p0 is equal to p1. + +So we assume that eta +is equal to one. + +So the probability of error, +which is also the probability + +of error when H is equal to +one-- in other words when a + +one actually enters the +communication system-- is + +equal to the probability of +error when H is equal to 0. + +In other words these two tails +here, when the threshold is + +equal to one you set the +threshold right there. + +The probability of this tail +is clearly equal to the + +probability of this tail. + +Just by symmetry. + +So these two error probabilities +are the same. + +And in fact they are just +q of a over the square + +root of n0 over 2. + +It's nice to put this +in terms of energy. + +We said before that energy is +sort of important in the + +communication field. + +So we call e sub b the energy +per bit that we're + +spending to send data. + +I mean don't worry about the +fact that we're only sending + +one bit and then we're tearing +the communication system down. + +Because pretty soon we're going +to send multiple bits. + +But the amount of energy we're +spending sending this one bit + +is a squared. + +At least back in this frame of +reference that we're looking + +at now, where we're just looking +at this discrete + +signal and single +variable noise. + +And n0 over 2 is the noise +variance of this particular + +random variable, z, so when we +write this out in terms of Eb, + +which is a squared, it looks +like this-- it's 2eb over n0. + +So the probability of error for +this binary communication + +problem is just the square +root of 2Eb over n0. + +Which is a formula that +you want to remember. + +It's the error probability for +binary detection when n0 over + +2 is the noise energy on this +one degree of freedom and Eb + +is the amount of energy you're +spending on this + +one degree of freedom. + +You will see about +50 variations of + +this as we go on. + +If you try to remember this +fundamental definition, it'll + +save you a lot of agony. + +Even so, everybody I know who +deals with this kind of thing + +always screws up the +factors of twos. + +And finally when they get all +done, they try to figure out + +from common sense or from +something else, what the + +factors of two ought to be. + +And they reduce their +probability of error to about + +a quarter after they're all done +with doing all of that. + +OK, so we spent a lot +of time analyzing + +binary antipodal signals. + +What about the binary non +antipodal signals? + +This is beautiful example of +Shannon's idea of studying the + +simplest cases first. + +If you have two signals, one of +which is b and one of which + +is b prime, and they can be put +anywhere on the real line. + +And what I've done, because I +didn't want to plot this whole + +picture again, is I just took +the zero out, and I replaced + +the zero by the point halfway +between these two points which + +is b plus b prime over 2. + +And then we look at it and we +say what happens if you have + +an arbitrary set of two points +anywhere on the real line? + +Well when I send this point the +likelihood, conditional on + +this point being sent, is +this Gaussian curve + +centered on b prime. + +When I send b the likelihood +is a Gaussian + +curve centered on b. + +And it is in fact the same curve +that we drew before. + +If in fact I replaced zero with +a center point between + +these two, which is b +plus b prime over 2. + +And if I then define a as this +distance in here, the + +probability of error that I +calculated before is the same + +as it was before. + +Now I would suggest to all of +you that you try to find the + +probability of error for this +system here, just not using + +what we've already done, and +just writing out the + +likelihood ratios as a function +of an arbitrary b + +prime and an arbitrary b and +finding a likelihood ratio, + +and calculating through +all of that. + +And most of you are capable of +calculating through all of it. + +But when you do so, you will +get a god awful looking + +formula, which just looks +totally messy. + +And by looking at the formula +you are not going to be able + +to realize that what's going +on is what we see here from + +the picture. + +And the only reason we figured +out what was going like the + +picture is we already +solved the problem + +for the Simpson case. + +OK so it never makes any sense +in this problem to look at + +this general case. + +You always want to say the +general case is just a special + +case of a special case. + +Where you just have to define +things slightly differently. + +OK, so we're going to do the +center point, then, I mean it + +might be a pilot tone. + +It might be any other non +information bearing signal. + +In other words were sending +the one bit. + +Sometimes for some reason or +other, you need to get + +synchronization. + +You need to get other things +in a communication system. + +And for that reason, you +send other things. + +We'll talk about a lot +of those later. + +But they don't change the error +probability at all. + +The error probability is +determined solely by the + +distance between these two +points which we call 2a. + +So probability of error remains +the same in terms of + +this distance. + +The energy per bit +now changes. + +The energy per bit is +the energy here + +plus the energy here. + +Which in fact is the energy +in the center + +point plus a squared. + +I mean we've done that in a +number of contexts, the way to + +find the energy in a binary +random variable is to take the + +energy in the center point +plus the energy in the + +difference. + +It's the same as finding the +fluctuation plus the + +square of the mean. + +It's that same underlying +idea. + +So any time you use non +antipodal and you shift things + +off the mean, you can +see what's going + +on very, very easily. + +You waste energy. + +I mean it might not be wasted, +you might have to waste it for + +some reason. + +But as far as a communication +is concerned you're simply + +wasting it. + +So your energy per bit changes, +but your probability + +of error remains the same. + +Because of that, you get a very +clear cut idea of what + +it's costing you to send +that pilot tone. + +Because in fact what you've done +is to just increase this + +energy, which we talk about +in terms of db. + +If c is equal to a in this case +which, as will see, is a + +common thing that happens in a +lot of systems, what you've + +lost is a factor three db. + +Because you're using twice as +much energy which is three db + +more energy, than you have +to use for the pure + +communication. + +So it's costing you three db to +do whatever silly thing you + +want to do for synchronization +or something else. + +Which is why people work very +hard to try to send signals + +which carry their own +synchronization + +information in them. + +And we will talk about that more +when we get to wireless + +and things like that. + +OK. + +Let's go on to real antipodal +vectors in + +white Gaussian noise. + +And again, let me point out to +you again that one of the + +remarkable things about +detection theory is once you + +understand detection for +antipodal binary signals and + +Gaussian noise, everything +else just follows along. + +OK, so here what we're going to +do is to assume that under + +the hypothesis H equals zero-- +in other words conditional on + +a zero entering the +communication system-- + +what we're going to send is not +a single degree, is not + +something in a single +degree of freedom. + +But we're actually going +to send a vector. + +And you can think of that if you +want to as sending a way + +form and breaking up the +waveform into an orthonormal + +expansion and a1 to +ak as being the + +coefficients in that expansion. + +So we're going to use +several degrees of + +freedom to send one signal. + +Yes? + +AUDIENCE: [INAUDIBLE] + +PROFESSOR: I'm only +sending one bit. + +And on Wednesday I'm going to +talk about what happens when + +we want to send multiple bits +or when we want to send a + +large number of signals in one +degree of freedom, or all + +those cases, multiple +hypotheses. + +You know what's going +to happen? + +It's going to turn out to be +a trivial problem again. + +Multiple hypotheses are no +harder than just binary + +hypotheses. + +So again, once you understand +the simplest case, all + +Gaussian problems turn +out to be solved. + +Just with minor variations +and minor tweaks. + +OK, so I have antipodal +vectors. + +One vector is a1 to a sub k. + +Under the other hypothesis we're +going to send minus a, + +which is the opposite vector. + +So if we're dealing with two +dimensional space with + +coordinates here and here, +if I send this I'm + +going to send this. + +If I send that I'm going to +send that, and so forth. + +As the opposite alternative. + +The likelihood ratio is then, +the probability of vector v + +conditional on sending this. + +I'm assuming here that the noise +is IID and each noise + +variable has mean zero and +variance n0 over 2. + +Namely, we're pretending we're +communication people here, + +using and n0 over 2 here. + +So the conditional density-- + +the likelihood of this output +vector given zero-- is just + +this density of z shifted +over by a. + +So it's what we've talked about +as the Gaussian density. + +Just this, which is just the +energy in v minus a is what + +that turns out to be. + +So the log likelihood ratio is +the ratio of this quantity to + +the density where H +is equal to one. + +And when H is equal to one, what +happens is the same thing + +as happened before. + +One makes this sign turn +into a plus sign. + +So when I look at the log +likelihood ratio, I want to + +take the ratio of this quantity +to the same quantity + +with a plus put into it. + +And when I take the log of that, +what happens is I get + +this term minus the opposite +term of the opposite side. + +So I have minus the norm squared +of v minus a plus the + +norm squared of v +plus a over n0. + +And again, if you multiply +this out, the v squareds + +cancel out. + +The a squareds cancel out. + +And you just get the inner +product terms. + +And strangely enough you get the +same formula that you got + +before, almost, except here you +have the inner product of + +v with a instead of just the +product of v times a. + +So in fact we just have a slight +generalization of the + +thing that we did before. + +In other words, the +scalar product is + +a sufficient statistic. + +Now what does that tell you? + +It tells you how to +build a detector. + +OK? + +It tells you when you have a +vector detection problem, the + +thing that you want to do is to +take this vector, v, that + +you have and form the inner +product of v times a. + +If in fact v is a waveform +and a is a waveform, + +what do you do then? + +Well the first thing you +do is to think of + +v as being a vector-- + +where it's the vector of +coefficients-- in the + +expansion for that waveform +and a in the same way. + +You look at what the inner +product is then, and then you + +say, "well what does that +correspond to when I deal with + +L2 waveforms?" What's the inner + +product for L2 waveforms? + +It's the integral of the product +of the waveforms. + +And how do you form the +integral of the + +product of the waveforms? + +You take this waveform here. + +You turn it around and you call +it a matched filter to a. + +And you take the received +waveform. + +You pass it through the max +filter for a, and you look at + +the output for it. + +Now, let's go back and look at +what all of this was doing. + +And for now let's forget +about the baseband to + +the passband business. + +Let's just look at this part +here because it's a little + +easier to see this first. + +So this comes in here. + +Now remember what +we were saying + +when we studied Nyquist. + +We said a neat thing to do was +to use a square root of the + +Nyquist pulse at the +transmitter. + +When you use a square root of +the Nyquist pulse at the + +transmitter, what you have is +orthogonality between the + +pulse and all of its shifts. + +Well now we don't much care +about the orthogonality + +between the pulse and all of the +shifts because we're only + +sending this one bit anyway. + +But it sort of looks like we're +going to be able to put + +that back in in a nice +convenient way. + +So we're sending this one pulse, +p of t, city and what + +did we do in this baseband +demodulator? + +We passed this through another +filter, q of t, which was the + +matched filter to p of t. + +What's our optimal detector +for maximum likelihood? + +It's to take whatever this +waveform was, pass it through + +the matched filter. + +In other words, to calculate +that inner product we just + +talked about. + +OK? + +So in fact when we were looking +at the Nyquist problem + +and worrying about inner symbol +interference, in fact + +what we were doing was also +doing the first part of an + +optimal MAP detector. + +And at this point what comes +out of here is a single + +number, v, which in fact now is +the inner product of this + +waveform at this point. + +With the waveform, +a, that we sent. + +OK? + +In other words, we started out +by saying, "let's suppose that + +what we have here is a number. + +What's the optimal detector to +build?" And then we go on and + +say, "OK, let's suppose we +look at the problem here. + +What's the optimal detector to +build now?" And the optimal + +detector to build now at this +point is this matched filter + +to this input waveform. + +Followed by the inner product +here-- which is what the match + +filter does for us-- followed +by our binary antipodal + +detector again. + +OK? + +So by studying the problem at +this point, we now understand + +what happens at this point. + +And do I have time to show you +what happens at this point? + +I don't know. + +Let me-- + +let's not do that at +least right now-- + +let's look at the picture of +this that we get when we just + +look at the problem when +we have two dimensions. + +So we're either going to +transmit a vector, a, or we're + +going to transmit a +vector, minus a. + +And think of this in +two dimensions. + +When we transmit the +vector, a, we have + +two dimensional noise. + +We've already pointed out that +two dimensional Gaussian noise + +has circular symmetry. + +Spherical symmetry in an +arbitrary number of dimension. + +So what happens is you get +these equal probability + +regions which are spreading out +like when you drop a rock + +into a pool of water. + +You see all of these things +spreading out in circles. + +And you then say, "OK, what's +this inner product going to + +correspond to?" Finding the +inner product and comparing it + +with a threshold. + +Well you can see geometrically +what's going to happen here. + +You're trying to do maximum +likelihood. + +And we already know we're +supposed to calculate the + +inner product, so what the inner +product is going to do + +is take whatever v that we +receive-- it's going to + +project it on to this line +between 0 and a. + +So if I got a v here I'm going +to project it down to here. + +And then what I'm going to do +is I'm going to compare the + +distance from here to there +with the distance + +from here to there. + +Which says first project, then +do the old decision in a one + +dimensional way. + +Now geometrically, this distance +squared is equal to + +this distance squared plus +this distance squared. + +And this distance squared is +equal to the same distance + +squared plus this distance +squared. + +So whatever you decide to do in +terms of these distances, + +you will also decide to do in +terms of these distances. + +Which also means that the +maximum likelihood regions + +that you're going to develop, +or in fact the maximum a + +posteriori probability regions +are simply planes. + +Which are perpendicular +to the line between + +minus a and plus a. + +OK? + +So if you're doing maximum +likelihood you just form a + +plane halfway between +these two points. + +Yeah? + +AUDIENCE: [UNINTELLIGIBLE] + +PROFESSOR: We got the error +probability just by first + +doing the projection and then +turning it into this scale or + +problem again. + +So in fact the error +probability-- + +What? + +AUDIENCE: [UNINTELLIGIBLE] + +PROFESSOR: The probability of +error is just the probability + +of error in the projection. + +Did I write it down someplace? + +Oh yeah, I did write it down. + +But I wrote it down, well +I sort of cheated. + +It's in the notes. + +I mean the likelihood ratio is +just a center product here + +which is a number. + +And when you find the error +probability, you just use the + +same q formula that +we used before. + +And in place of a +you substitute-- + +in place of a you substitute the +inner product of v with a. + +Which is the corresponding +quantity. + +So it's q of 4va +divided by n0. + +OK? + +So that's the maximum likelihood +error probability. + +OK? + +In other words, nothing +new has happened here. + +You just go through the match +filter and then you do this + +same one dimensional problem +that we've already + +figured out how to do. + +I think I'm going to stop there +and we'll do the complex + +case which really corresponds to +what happens after baseband + +to passband then passband +to baseband. \ No newline at end of file diff --git a/8gGbViZjoRw.txt b/8gGbViZjoRw.txt new file mode 100644 index 0000000000000000000000000000000000000000..f2598c0fe81de5b8dab67c8a848759674c47be2a --- /dev/null +++ b/8gGbViZjoRw.txt @@ -0,0 +1,1811 @@ +align:start position:0% + +hi welcome back to recitation in lecture + + align:start position:0% +hi welcome back to recitation in lecture + + + align:start position:0% +hi welcome back to recitation in lecture +you've been talking about implicitly + + align:start position:0% +you've been talking about implicitly + + + align:start position:0% +you've been talking about implicitly +defined functions and and implicit + + align:start position:0% +defined functions and and implicit + + + align:start position:0% +defined functions and and implicit +differentiation um so one of the reasons + + align:start position:0% +differentiation um so one of the reasons + + + align:start position:0% +differentiation um so one of the reasons +that these are important is or or that + + align:start position:0% +that these are important is or or that + + + align:start position:0% +that these are important is or or that +that implicit different differentiation + + align:start position:0% +that implicit different differentiation + + + align:start position:0% +that implicit different differentiation +is important is that sometimes you have + + align:start position:0% +is important is that sometimes you have + + + align:start position:0% +is important is that sometimes you have +a function defined implicitly and you + + align:start position:0% +a function defined implicitly and you + + + align:start position:0% +a function defined implicitly and you +can't solve for it you don't have any + + align:start position:0% +can't solve for it you don't have any + + + align:start position:0% +can't solve for it you don't have any +algebraic method for for computing the + + align:start position:0% +algebraic method for for computing the + + + align:start position:0% +algebraic method for for computing the +function values um as a formula say so + + align:start position:0% +function values um as a formula say so + + + align:start position:0% +function values um as a formula say so +for example um this function that I've + + align:start position:0% +for example um this function that I've + + + align:start position:0% +for example um this function that I've +written on the board that I've called W + + align:start position:0% +written on the board that I've called W + + + align:start position:0% +written on the board that I've called W +of X is is defined implicitly by the + + align:start position:0% +of X is is defined implicitly by the + + + align:start position:0% +of X is is defined implicitly by the +equation that W of x + 1 quantity time e + + align:start position:0% +equation that W of x + 1 quantity time e + + + align:start position:0% +equation that W of x + 1 quantity time e +to the W ofx is equal to X for all X so + + align:start position:0% +to the W ofx is equal to X for all X so + + + align:start position:0% +to the W ofx is equal to X for all X so +this this function um some of its values + + align:start position:0% +this this function um some of its values + + + align:start position:0% +this this function um some of its values +you can you can guess like like at x + + align:start position:0% +you can you can guess like like at x + + + align:start position:0% +you can you can guess like like at x +equals zero the function value is going + + align:start position:0% +equals zero the function value is going + + + align:start position:0% +equals zero the function value is going +to be negative one and the reason is + + align:start position:0% +to be negative one and the reason is + + + align:start position:0% +to be negative one and the reason is +that this can't ever be zero so the only + + align:start position:0% +that this can't ever be zero so the only + + + align:start position:0% +that this can't ever be zero so the only +way to get this side to be zero is if W + + align:start position:0% +way to get this side to be zero is if W + + + align:start position:0% +way to get this side to be zero is if W +is negative 1 if this term is zero so + + align:start position:0% +is negative 1 if this term is zero so + + + align:start position:0% +is negative 1 if this term is zero so +some of its some of its values are are + + align:start position:0% +some of its some of its values are are + + + align:start position:0% +some of its some of its values are are +easy to compute but some of its values + + align:start position:0% +easy to compute but some of its values + + + align:start position:0% +easy to compute but some of its values +aren't so for example if I asked you + + align:start position:0% +aren't so for example if I asked you + + + align:start position:0% +aren't so for example if I asked you +what w of three Hales is it's it's very + + align:start position:0% +what w of three Hales is it's it's very + + + align:start position:0% +what w of three Hales is it's it's very +hard there there's no algebraic way you + + align:start position:0% +hard there there's no algebraic way you + + + align:start position:0% +hard there there's no algebraic way you +can manipulate this equation that will + + align:start position:0% +can manipulate this equation that will + + + align:start position:0% +can manipulate this equation that will +let you figure that out um so in that + + align:start position:0% +let you figure that out um so in that + + + align:start position:0% +let you figure that out um so in that +situation you might still care about + + align:start position:0% +situation you might still care about + + + align:start position:0% +situation you might still care about +what what the function value is um so + + align:start position:0% +what what the function value is um so + + + align:start position:0% +what what the function value is um so +what can you do well you can you can try + + align:start position:0% +what can you do well you can you can try + + + align:start position:0% +what can you do well you can you can try +and find a numerical approximation so in + + align:start position:0% +and find a numerical approximation so in + + + align:start position:0% +and find a numerical approximation so in +this problem I'd like you to try and + + align:start position:0% +this problem I'd like you to try and + + + align:start position:0% +this problem I'd like you to try and +estimate the value W of 3 by using a + + align:start position:0% +estimate the value W of 3 by using a + + + align:start position:0% +estimate the value W of 3 by using a +linear approximation to to the function + + align:start position:0% +linear approximation to to the function + + + align:start position:0% +linear approximation to to the function +to the to the to the curve yeah a linear + + align:start position:0% +to the to the to the curve yeah a linear + + + align:start position:0% +to the to the to the curve yeah a linear +approximation of the function W ofx + + align:start position:0% +approximation of the function W ofx + + + align:start position:0% +approximation of the function W ofx +um in order in order to compute this + + align:start position:0% +um in order in order to compute this + + + align:start position:0% +um in order in order to compute this +value so as a hint I've given you so + + align:start position:0% +value so as a hint I've given you so + + + align:start position:0% +value so as a hint I've given you so +you're trying to compute W of three + + align:start position:0% +you're trying to compute W of three + + + align:start position:0% +you're trying to compute W of three +Hales as a hint I I'm pointing out to + + align:start position:0% +Hales as a hint I I'm pointing out to + + + align:start position:0% +Hales as a hint I I'm pointing out to +you that that W of one is zero right if + + align:start position:0% +you that that W of one is zero right if + + + align:start position:0% +you that that W of one is zero right if +if you put in x equal Z and W of 0 + + align:start position:0% +if you put in x equal Z and W of 0 + + + align:start position:0% +if you put in x equal Z and W of 0 +equals uh sorry if you put an xals 1 and + + align:start position:0% +equals uh sorry if you put an xals 1 and + + + align:start position:0% +equals uh sorry if you put an xals 1 and +W 1 equals 0 on the left hand side you + + align:start position:0% +W 1 equals 0 on the left hand side you + + + align:start position:0% +W 1 equals 0 on the left hand side you +do indeed get get one as as you should + + align:start position:0% +do indeed get get one as as you should + + + align:start position:0% +do indeed get get one as as you should +so okay + + align:start position:0% +so okay + + + align:start position:0% +so okay +so um good so so that that that'll give + + align:start position:0% +so um good so so that that that'll give + + + align:start position:0% +so um good so so that that that'll give +you a hint about where you could base + + align:start position:0% +you a hint about where you could base + + + align:start position:0% +you a hint about where you could base +your your linear approximation so why + + align:start position:0% +your your linear approximation so why + + + align:start position:0% +your your linear approximation so why +don't you pause the video take a few + + align:start position:0% +don't you pause the video take a few + + + align:start position:0% +don't you pause the video take a few +minutes to work this out come back and + + align:start position:0% +minutes to work this out come back and + + + align:start position:0% +minutes to work this out come back and +we can work it out + + align:start position:0% + + + + align:start position:0% + +together + + align:start position:0% +together + + + align:start position:0% +together +all right welcome back so hopefully + + align:start position:0% +all right welcome back so hopefully + + + align:start position:0% +all right welcome back so hopefully +you've had a chance to uh to work on + + align:start position:0% +you've had a chance to uh to work on + + + align:start position:0% +you've had a chance to uh to work on +this question a little bit so uh in + + align:start position:0% +this question a little bit so uh in + + + align:start position:0% +this question a little bit so uh in +order to do this linear approximation + + align:start position:0% +order to do this linear approximation + + + align:start position:0% +order to do this linear approximation +that we want what we need to know or we + + align:start position:0% +that we want what we need to know or we + + + align:start position:0% +that we want what we need to know or we +need to know a base point and we need to + + align:start position:0% +need to know a base point and we need to + + + align:start position:0% +need to know a base point and we need to +know the derivative of the function at + + align:start position:0% +know the derivative of the function at + + + align:start position:0% +know the derivative of the function at +that base point and those those are the + + align:start position:0% +that base point and those those are the + + + align:start position:0% +that base point and those those are the +the two pieces of data you need in order + + align:start position:0% +the two pieces of data you need in order + + + align:start position:0% +the two pieces of data you need in order +to construct a linear approximation so + + align:start position:0% +to construct a linear approximation so + + + align:start position:0% +to construct a linear approximation so +we we have we have a good candidate for + + align:start position:0% +we we have we have a good candidate for + + + align:start position:0% +we we have we have a good candidate for +a base Point here which is the point 1 Z + + align:start position:0% +a base Point here which is the point 1 Z + + + align:start position:0% +a base Point here which is the point 1 Z +so this this curve whatever it looks + + align:start position:0% +so this this curve whatever it looks + + + align:start position:0% +so this this curve whatever it looks +like it passes through the point 1 Z and + + align:start position:0% +like it passes through the point 1 Z and + + + align:start position:0% +like it passes through the point 1 Z and +that's the point we're going to use for + + align:start position:0% +that's the point we're going to use for + + + align:start position:0% +that's the point we're going to use for +our for our approximation so we're going + + align:start position:0% +our for our approximation so we're going + + + align:start position:0% +our for our approximation so we're going +to + + align:start position:0% + + + + align:start position:0% + +use the linear + + align:start position:0% +use the linear + + + align:start position:0% +use the linear +approximation W of + + align:start position:0% +approximation W of + + + align:start position:0% +approximation W of +X is approximately equal + + align:start position:0% +X is approximately equal + + + align:start position:0% +X is approximately equal +to + + align:start position:0% +to + + + align:start position:0% +to +W Prime of 1 + + align:start position:0% +W Prime of 1 + + + align:start position:0% +W Prime of 1 +* x + + align:start position:0% +* x + + + align:start position:0% +* x +-1 + W of + + align:start position:0% + + + + align:start position:0% + +1 when X is approximately equal to one + + align:start position:0% +1 when X is approximately equal to one + + + align:start position:0% +1 when X is approximately equal to one +so this is the linear approximation + + align:start position:0% +so this is the linear approximation + + + align:start position:0% +so this is the linear approximation +we're going to use and and we have that + + align:start position:0% +we're going to use and and we have that + + + align:start position:0% +we're going to use and and we have that +W of 1 here is zero so this is this is + + align:start position:0% +W of 1 here is zero so this is this is + + + align:start position:0% +W of 1 here is zero so this is this is +equal + + align:start position:0% +equal + + + align:start position:0% +equal +to W Prime of 1 + + align:start position:0% +to W Prime of 1 + + + align:start position:0% +to W Prime of 1 +time x minus one just the the W of one + + align:start position:0% +time x minus one just the the W of one + + + align:start position:0% +time x minus one just the the W of one +is zero it just goes away so in order to + + align:start position:0% +is zero it just goes away so in order to + + + align:start position:0% +is zero it just goes away so in order to +estimate W of X and in particular W of + + align:start position:0% +estimate W of X and in particular W of + + + align:start position:0% +estimate W of X and in particular W of +three halves uh what we need to know is + + align:start position:0% +three halves uh what we need to know is + + + align:start position:0% +three halves uh what we need to know is +we need to know the derivative of w + + align:start position:0% +we need to know the derivative of w + + + align:start position:0% +we need to know the derivative of w +okay um and to get the derivative of w + + align:start position:0% +okay um and to get the derivative of w + + + align:start position:0% +okay um and to get the derivative of w +we need to use well we have only one + + align:start position:0% +we need to use well we have only one + + + align:start position:0% +we need to use well we have only one +piece of information about W which is we + + align:start position:0% +piece of information about W which is we + + + align:start position:0% +piece of information about W which is we +have that that it that it's defined by + + align:start position:0% +have that that it that it's defined by + + + align:start position:0% +have that that it that it's defined by +this implicit equation so in order to to + + align:start position:0% +this implicit equation so in order to to + + + align:start position:0% +this implicit equation so in order to to +get the derivative of w we have to use + + align:start position:0% +get the derivative of w we have to use + + + align:start position:0% +get the derivative of w we have to use +implicit differentiation okay so let's + + align:start position:0% +implicit differentiation okay so let's + + + align:start position:0% +implicit differentiation okay so let's +let's do that um so if we if we + + align:start position:0% +let's do that um so if we if we + + + align:start position:0% +let's do that um so if we if we +implicitly differentiate this equation + + align:start position:0% +implicitly differentiate this equation + + + align:start position:0% +implicitly differentiate this equation +so let's let's start with the the right + + align:start position:0% +so let's let's start with the the right + + + align:start position:0% +so let's let's start with the the right +hand side's going to be really easy + + align:start position:0% +hand side's going to be really easy + + + align:start position:0% +hand side's going to be really easy +right we're going to differentiate with + + align:start position:0% +right we're going to differentiate with + + + align:start position:0% +right we're going to differentiate with +respect to X the right hand side's going + + align:start position:0% +respect to X the right hand side's going + + + align:start position:0% +respect to X the right hand side's going +to be one on the left hand side is going + + align:start position:0% +to be one on the left hand side is going + + + align:start position:0% +to be one on the left hand side is going +to be a little more complicated we have + + align:start position:0% +to be a little more complicated we have + + + align:start position:0% +to be a little more complicated we have +a product and then this piece we're + + align:start position:0% +a product and then this piece we're + + + align:start position:0% +a product and then this piece we're +going to we're going to have a chain + + align:start position:0% +going to we're going to have a chain + + + align:start position:0% +going to we're going to have a chain +rule situation right we have e to the W + + align:start position:0% +rule situation right we have e to the W + + + align:start position:0% +rule situation right we have e to the W +of X so so okay + + align:start position:0% + + + + align:start position:0% + +so so we're going to take an implicit + + align:start position:0% +so so we're going to take an implicit + + + align:start position:0% +so so we're going to take an implicit +derivative and on the left so okay so + + align:start position:0% +derivative and on the left so okay so + + + align:start position:0% +derivative and on the left so okay so +from the product rule First We Take the + + align:start position:0% +from the product rule First We Take the + + + align:start position:0% +from the product rule First We Take the +derivative of the first part so that's + + align:start position:0% +derivative of the first part so that's + + + align:start position:0% +derivative of the first part so that's +just + + align:start position:0% +just + + + align:start position:0% +just +W Prime of X time the second part that's + + align:start position:0% +W Prime of X time the second part that's + + + align:start position:0% +W Prime of X time the second part that's +e to the W of + + align:start position:0% +e to the W of + + + align:start position:0% +e to the W of +X plus the first part that's W ofx + 1 + + align:start position:0% +X plus the first part that's W ofx + 1 + + + align:start position:0% +X plus the first part that's W ofx + 1 +times the derivative of the second part + + align:start position:0% +times the derivative of the second part + + + align:start position:0% +times the derivative of the second part +so the second part is e to the W of X so + + align:start position:0% +so the second part is e to the W of X so + + + align:start position:0% +so the second part is e to the W of X so +that gives me an e to the W of x + + align:start position:0% +that gives me an e to the W of x + + + align:start position:0% +that gives me an e to the W of x +times W Prime of X that's the that's the + + align:start position:0% +times W Prime of X that's the that's the + + + align:start position:0% +times W Prime of X that's the that's the +chain rule so that's what happens when I + + align:start position:0% +chain rule so that's what happens when I + + + align:start position:0% +chain rule so that's what happens when I +differentiate the left hand side and on + + align:start position:0% +differentiate the left hand side and on + + + align:start position:0% +differentiate the left hand side and on +the right hand side + + align:start position:0% +the right hand side + + + align:start position:0% +the right hand side +I take the derivative of x and I get one + + align:start position:0% +I take the derivative of x and I get one + + + align:start position:0% +I take the derivative of x and I get one +okay good um so now I've got this + + align:start position:0% +okay good um so now I've got this + + + align:start position:0% +okay good um so now I've got this +equation and I need to solve this + + align:start position:0% +equation and I need to solve this + + + align:start position:0% +equation and I need to solve this +equation for w Prime because if you look + + align:start position:0% +equation for w Prime because if you look + + + align:start position:0% +equation for w Prime because if you look +up here that's what I want I want a a + + align:start position:0% +up here that's what I want I want a a + + + align:start position:0% +up here that's what I want I want a a +particular value of w Prime and as + + align:start position:0% +particular value of w Prime and as + + + align:start position:0% +particular value of w Prime and as +always happens in implicit + + align:start position:0% +always happens in implicit + + + align:start position:0% +always happens in implicit +differentiation from the point of view + + align:start position:0% +differentiation from the point of view + + + align:start position:0% +differentiation from the point of view +of this W Prime it's only involved in + + align:start position:0% +of this W Prime it's only involved in + + + align:start position:0% +of this W Prime it's only involved in +the in the equation in a very simple way + + align:start position:0% +the in the equation in a very simple way + + + align:start position:0% +the in the equation in a very simple way +so there's it multiplied by functions of + + align:start position:0% +so there's it multiplied by functions of + + + align:start position:0% +so there's it multiplied by functions of +X and W of X but not there it's just you + + align:start position:0% +X and W of X but not there it's just you + + + align:start position:0% +X and W of X but not there it's just you +know it's just multiplied by something + + align:start position:0% +know it's just multiplied by something + + + align:start position:0% +know it's just multiplied by something +that doesn't involve W Prime at all and + + align:start position:0% +that doesn't involve W Prime at all and + + + align:start position:0% +that doesn't involve W Prime at all and +then here it's multiplied by something + + align:start position:0% +then here it's multiplied by something + + + align:start position:0% +then here it's multiplied by something +that doesn't involve W Prime at all so + + align:start position:0% +that doesn't involve W Prime at all so + + + align:start position:0% +that doesn't involve W Prime at all so +you can just collect your W primes and + + align:start position:0% +you can just collect your W primes and + + + align:start position:0% +you can just collect your W primes and +divide through you know it's it's just + + align:start position:0% +divide through you know it's it's just + + + align:start position:0% +divide through you know it's it's just +like solving a linear equation um so + + align:start position:0% +like solving a linear equation um so + + + align:start position:0% +like solving a linear equation um so +here if we collect our W primes this is + + align:start position:0% +here if we collect our W primes this is + + + align:start position:0% +here if we collect our W primes this is +W Prime of x + + align:start position:0% +W Prime of x + + + align:start position:0% +W Prime of x +times looks like w of + + align:start position:0% +times looks like w of + + + align:start position:0% +times looks like w of +x + 2 time e to the + + align:start position:0% +x + 2 time e to the + + + align:start position:0% +x + 2 time e to the +W of X did I get that + + align:start position:0% +W of X did I get that + + + align:start position:0% +W of X did I get that +right looks good okay so that's still + + align:start position:0% +right looks good okay so that's still + + + align:start position:0% +right looks good okay so that's still +equal to one and so that means that W + + align:start position:0% +equal to one and so that means that W + + + align:start position:0% +equal to one and so that means that W +Prime of X is just well just you know + + align:start position:0% +Prime of X is just well just you know + + + align:start position:0% +Prime of X is just well just you know +it's equal to one + + align:start position:0% +it's equal to one + + + align:start position:0% +it's equal to one +over W of + + align:start position:0% +over W of + + + align:start position:0% +over W of +X+ 2 * e to W of X okay so this is true + + align:start position:0% +X+ 2 * e to W of X okay so this is true + + + align:start position:0% +X+ 2 * e to W of X okay so this is true +for every X but I don't need this + + align:start position:0% +for every X but I don't need this + + + align:start position:0% +for every X but I don't need this +equation for every X I just need the + + align:start position:0% +equation for every X I just need the + + + align:start position:0% +equation for every X I just need the +particular value of w Prime at one so + + align:start position:0% +particular value of w Prime at one so + + + align:start position:0% +particular value of w Prime at one so +that's so so I'm going to take this + + align:start position:0% +that's so so I'm going to take this + + + align:start position:0% +that's so so I'm going to take this +equation then and I'm just going to put + + align:start position:0% +equation then and I'm just going to put + + + align:start position:0% +equation then and I'm just going to put +in xals 1 so I put in xals 1 let me do + + align:start position:0% +in xals 1 so I put in xals 1 let me do + + + align:start position:0% +in xals 1 so I put in xals 1 let me do +it over here so I get W Prime of one and + + align:start position:0% +it over here so I get W Prime of one and + + + align:start position:0% +it over here so I get W Prime of one and +I just everywhere I had an X I put in a + + align:start position:0% +I just everywhere I had an X I put in a + + + align:start position:0% +I just everywhere I had an X I put in a +one so actually in this equation the + + align:start position:0% +one so actually in this equation the + + + align:start position:0% +one so actually in this equation the +only place X appears is in the argument + + align:start position:0% +only place X appears is in the argument + + + align:start position:0% +only place X appears is in the argument +of w so this is W of 1 plus 2 * e to the + + align:start position:0% +of w so this is W of 1 plus 2 * e to the + + + align:start position:0% +of w so this is W of 1 plus 2 * e to the +W of 1 okay so in order to get W Prime + + align:start position:0% +W of 1 okay so in order to get W Prime + + + align:start position:0% +W of 1 okay so in order to get W Prime +of 1 I need to know what w of one is but + + align:start position:0% +of 1 I need to know what w of one is but + + + align:start position:0% +of 1 I need to know what w of one is but +I had that I had it was right back here + + align:start position:0% +I had that I had it was right back here + + + align:start position:0% +I had that I had it was right back here +that was the that was my hint to you + + align:start position:0% +that was the that was my hint to you + + + align:start position:0% +that was the that was my hint to you +right this is why we're using this point + + align:start position:0% +right this is why we're using this point + + + align:start position:0% +right this is why we're using this point +as a base point which is we know the + + align:start position:0% +as a base point which is we know the + + + align:start position:0% +as a base point which is we know the +value of W uh for this value of x so we + + align:start position:0% +value of W uh for this value of x so we + + + align:start position:0% +value of W uh for this value of x so we +we take that value so w of one is zero + + align:start position:0% +we take that value so w of one is zero + + + align:start position:0% +we take that value so w of one is zero +so this is just 1 over well 0 + 2 is 2 + + align:start position:0% +so this is just 1 over well 0 + 2 is 2 + + + align:start position:0% +so this is just 1 over well 0 + 2 is 2 +and E to the 0 is one so it's just one + + align:start position:0% +and E to the 0 is one so it's just one + + + align:start position:0% +and E to the 0 is one so it's just one +over two sorry that's written a little + + align:start position:0% +over two sorry that's written a little + + + align:start position:0% +over two sorry that's written a little +oddly we can make it two * one all right + + align:start position:0% +oddly we can make it two * one all right + + + align:start position:0% +oddly we can make it two * one all right +so one over + + align:start position:0% + + + + align:start position:0% + +two okay so I take that back upstairs to + + align:start position:0% +two okay so I take that back upstairs to + + + align:start position:0% +two okay so I take that back upstairs to +this equation that I had here and I have + + align:start position:0% +this equation that I had here and I have + + + align:start position:0% +this equation that I had here and I have +that W of X is approximately equal to W + + align:start position:0% +that W of X is approximately equal to W + + + align:start position:0% +that W of X is approximately equal to W +Prime of 1 * x + + align:start position:0% +Prime of 1 * x + + + align:start position:0% +Prime of 1 * x +-1 + + align:start position:0% +-1 + + + align:start position:0% +-1 +so w of X is approximately equal to W + + align:start position:0% +so w of X is approximately equal to W + + + align:start position:0% +so w of X is approximately equal to W +Prime of 1 we saw + + align:start position:0% +Prime of 1 we saw + + + align:start position:0% +Prime of 1 we saw +is 12 * X - + + align:start position:0% + + + + align:start position:0% + +1 and that approximation was good near + + align:start position:0% +1 and that approximation was good near + + + align:start position:0% +1 and that approximation was good near +our base point so that's that's good + + align:start position:0% +our base point so that's that's good + + + align:start position:0% +our base point so that's that's good +when X is near + + align:start position:0% + + + + align:start position:0% + +one all right and then so this is this + + align:start position:0% +one all right and then so this is this + + + align:start position:0% +one all right and then so this is this +is the linear approximation and I asked + + align:start position:0% +is the linear approximation and I asked + + + align:start position:0% +is the linear approximation and I asked +for for the linear approximation its + + align:start position:0% +for for the linear approximation its + + + align:start position:0% +for for the linear approximation its +value at the particular point xal + + align:start position:0% +value at the particular point xal + + + align:start position:0% +value at the particular point xal +3es so w of 3es + + align:start position:0% +3es so w of 3es + + + align:start position:0% +3es so w of 3es +is + + align:start position:0% +is + + + align:start position:0% +is +approximately 12 time + + align:start position:0% +approximately 12 time + + + align:start position:0% +approximately 12 time +well 3es minus 1 is also a + + align:start position:0% +well 3es minus 1 is also a + + + align:start position:0% +well 3es minus 1 is also a +half so this is a quarter okay so this + + align:start position:0% +half so this is a quarter okay so this + + + align:start position:0% +half so this is a quarter okay so this +is our estimate for w of three Hales W + + align:start position:0% +is our estimate for w of three Hales W + + + align:start position:0% +is our estimate for w of three Hales W +of three halves is approximately 1/4 if + + align:start position:0% +of three halves is approximately 1/4 if + + + align:start position:0% +of three halves is approximately 1/4 if +you wanted a better estimate you could + + align:start position:0% +you wanted a better estimate you could + + + align:start position:0% +you wanted a better estimate you could +try iterating this process now now you + + align:start position:0% +try iterating this process now now you + + + align:start position:0% +try iterating this process now now you +might have a a you know you could or + + align:start position:0% +might have a a you know you could or + + + align:start position:0% +might have a a you know you could or +choosing some base Point even closer if + + align:start position:0% +choosing some base Point even closer if + + + align:start position:0% +choosing some base Point even closer if +you could figure out the the value of w + + align:start position:0% +you could figure out the the value of w + + + align:start position:0% +you could figure out the the value of w +and X near near that um near this this + + align:start position:0% +and X near near that um near this this + + + align:start position:0% +and X near near that um near this this +point that you're interested in three + + align:start position:0% +point that you're interested in three + + + align:start position:0% +point that you're interested in three +halves um so just to to sum up what we + + align:start position:0% +halves um so just to to sum up what we + + + align:start position:0% +halves um so just to to sum up what we +did was we had this implicitly defined + + align:start position:0% +did was we had this implicitly defined + + + align:start position:0% +did was we had this implicitly defined +function w we wanted to estimate its + + align:start position:0% +function w we wanted to estimate its + + + align:start position:0% +function w we wanted to estimate its +value at a point where we couldn't + + align:start position:0% +value at a point where we couldn't + + + align:start position:0% +value at a point where we couldn't +compute it explicitly so what we did was + + align:start position:0% +compute it explicitly so what we did was + + + align:start position:0% +compute it explicitly so what we did was +we did our normal linear approximation + + align:start position:0% +we did our normal linear approximation + + + align:start position:0% +we did our normal linear approximation +method right so we we wrote down our our + + align:start position:0% +method right so we we wrote down our our + + + align:start position:0% +method right so we we wrote down our our +normal linear approximation formula the + + align:start position:0% +normal linear approximation formula the + + + align:start position:0% +normal linear approximation formula the +only thing that was slightly unusual is + + align:start position:0% +only thing that was slightly unusual is + + + align:start position:0% +only thing that was slightly unusual is +that we had to use implicit + + align:start position:0% +that we had to use implicit + + + align:start position:0% +that we had to use implicit +differentiation in order to compute the + + align:start position:0% +differentiation in order to compute the + + + align:start position:0% +differentiation in order to compute the +derivative that appears in the linear + + align:start position:0% +derivative that appears in the linear + + + align:start position:0% +derivative that appears in the linear +approximation we implicitly + + align:start position:0% +approximation we implicitly + + + align:start position:0% +approximation we implicitly +differentiated okay so that that + + align:start position:0% +differentiated okay so that that + + + align:start position:0% +differentiated okay so that that +happened just like normal and then at + + align:start position:0% +happened just like normal and then at + + + align:start position:0% +happened just like normal and then at +the end we plugged in the values that we + + align:start position:0% +the end we plugged in the values that we + + + align:start position:0% +the end we plugged in the values that we +were interested in to actually compute + + align:start position:0% +were interested in to actually compute + + + align:start position:0% +were interested in to actually compute +the the the particular value of that + + align:start position:0% +the the the particular value of that + + + align:start position:0% +the the the particular value of that +approximation so I'll end there \ No newline at end of file diff --git a/8sgl_wzzQUY.txt b/8sgl_wzzQUY.txt new file mode 100644 index 0000000000000000000000000000000000000000..7efe6d82eb15a964416d0110f3f3e867b3bff5ad --- /dev/null +++ b/8sgl_wzzQUY.txt @@ -0,0 +1,9523 @@ +align:start position:0% + +today and next lecture we are going to + + align:start position:0% +today and next lecture we are going to + + + align:start position:0% +today and next lecture we are going to +turn to a topic that's as I've + + align:start position:0% +turn to a topic that's as I've + + + align:start position:0% +turn to a topic that's as I've +highlighted previously woefully missing + + align:start position:0% +highlighted previously woefully missing + + + align:start position:0% +highlighted previously woefully missing +from this class and from Bas a lot of + + align:start position:0% +from this class and from Bas a lot of + + + align:start position:0% +from this class and from Bas a lot of +basic economics which is we're going to + + align:start position:0% +basic economics which is we're going to + + + align:start position:0% +basic economics which is we're going to +start talking about Equity this class + + align:start position:0% +start talking about Equity this class + + + align:start position:0% +start talking about Equity this class +has been totally focused on efficiency + + align:start position:0% +has been totally focused on efficiency + + + align:start position:0% +has been totally focused on efficiency +we've come back and back again to ever + + align:start position:0% +we've come back and back again to ever + + + align:start position:0% +we've come back and back again to ever +since we did the lecture on consumer and + + align:start position:0% +since we did the lecture on consumer and + + + align:start position:0% +since we did the lecture on consumer and +producer Surplus we've talked about a + + align:start position:0% +producer Surplus we've talked about a + + + align:start position:0% +producer Surplus we've talked about a +particular normative perspective which + + align:start position:0% +particular normative perspective which + + + align:start position:0% +particular normative perspective which +is the goal of society is to basically + + align:start position:0% +is the goal of society is to basically + + + align:start position:0% +is the goal of society is to basically +maximize total social surplus the goal + + align:start position:0% +maximize total social surplus the goal + + + align:start position:0% +maximize total social surplus the goal +of societ is really to maximize the pi + + align:start position:0% +of societ is really to maximize the pi + + + align:start position:0% +of societ is really to maximize the pi +and we don't really care how it's + + align:start position:0% +and we don't really care how it's + + + align:start position:0% +and we don't really care how it's +distributed and this is Illustrated as I + + align:start position:0% +distributed and this is Illustrated as I + + + align:start position:0% +distributed and this is Illustrated as I +mentioned before nowhere more starkly + + align:start position:0% +mentioned before nowhere more starkly + + + align:start position:0% +mentioned before nowhere more starkly +than the fact that two different Market + + align:start position:0% +than the fact that two different Market + + + align:start position:0% +than the fact that two different Market +outcomes have the exact same welfare + + align:start position:0% +outcomes have the exact same welfare + + + align:start position:0% +outcomes have the exact same welfare +consequences one is a perfectly + + align:start position:0% +consequences one is a perfectly + + + align:start position:0% +consequences one is a perfectly +competitive + + align:start position:0% +competitive + + + align:start position:0% +competitive +market and one is a perfectly price + + align:start position:0% +market and one is a perfectly price + + + align:start position:0% +market and one is a perfectly price +discriminating + + align:start position:0% +discriminating + + + align:start position:0% +discriminating +monopolist both of those Market outcomes + + align:start position:0% +monopolist both of those Market outcomes + + + align:start position:0% +monopolist both of those Market outcomes +yield maximum social + + align:start position:0% +yield maximum social + + + align:start position:0% +yield maximum social +surplus yet they feel very different and + + align:start position:0% +surplus yet they feel very different and + + + align:start position:0% +surplus yet they feel very different and +outcome where consumers and producers + + align:start position:0% +outcome where consumers and producers + + + align:start position:0% +outcome where consumers and producers +split the pie feels to us innately very + + align:start position:0% +split the pie feels to us innately very + + + align:start position:0% +split the pie feels to us innately very +different than an outcome where + + align:start position:0% +different than an outcome where + + + align:start position:0% +different than an outcome where +producers get to keep it all and that's + + align:start position:0% +producers get to keep it all and that's + + + align:start position:0% +producers get to keep it all and that's +because innately we as humans care not + + align:start position:0% +because innately we as humans care not + + + align:start position:0% +because innately we as humans care not +just about efficiency but fairness about + + align:start position:0% +just about efficiency but fairness about + + + align:start position:0% +just about efficiency but fairness about +equity and we actually care about not + + align:start position:0% +equity and we actually care about not + + + align:start position:0% +equity and we actually care about not +just how much stuff gets produced but + + align:start position:0% +just how much stuff gets produced but + + + align:start position:0% +just how much stuff gets produced but +who gets + + align:start position:0% +who gets + + + align:start position:0% +who gets +it now in that particular + + align:start position:0% +it now in that particular + + + align:start position:0% +it now in that particular +example you get two very different + + align:start position:0% +example you get two very different + + + align:start position:0% +example you get two very different +distributional outcomes with the same + + align:start position:0% +distributional outcomes with the same + + + align:start position:0% +distributional outcomes with the same +level of efficiency but that's actually + + align:start position:0% +level of efficiency but that's actually + + + align:start position:0% +level of efficiency but that's actually +pretty unique it turns out generally + + align:start position:0% +pretty unique it turns out generally + + + align:start position:0% +pretty unique it turns out generally +that different distributional outcomes + + align:start position:0% +that different distributional outcomes + + + align:start position:0% +that different distributional outcomes +different levels of fairness come at + + align:start position:0% +different levels of fairness come at + + + align:start position:0% +different levels of fairness come at +different levels of efficiency and that + + align:start position:0% +different levels of efficiency and that + + + align:start position:0% +different levels of efficiency and that +we leads to what we fundamentally call + + align:start position:0% +we leads to what we fundamentally call + + + align:start position:0% +we leads to what we fundamentally call +the equity efficiency + + align:start position:0% +the equity efficiency + + + align:start position:0% +the equity efficiency +tradeoff that basically to get more + + align:start position:0% +tradeoff that basically to get more + + + align:start position:0% +tradeoff that basically to get more +Equitable outcomes often requires less + + align:start position:0% +Equitable outcomes often requires less + + + align:start position:0% +Equitable outcomes often requires less +efficient + + align:start position:0% +efficient + + + align:start position:0% +efficient +outcomes and our goal as economists is + + align:start position:0% +outcomes and our goal as economists is + + + align:start position:0% +outcomes and our goal as economists is +to decide is it worth it how do we think + + align:start position:0% +to decide is it worth it how do we think + + + align:start position:0% +to decide is it worth it how do we think +about whether a potential sacrifice in + + align:start position:0% +about whether a potential sacrifice in + + + align:start position:0% +about whether a potential sacrifice in +efficiency is worth a gain in equity + + align:start position:0% +efficiency is worth a gain in equity + + + align:start position:0% +efficiency is worth a gain in equity +your fairness and the best way to think + + align:start position:0% +your fairness and the best way to think + + + align:start position:0% +your fairness and the best way to think +about this was posed by The Economist + + align:start position:0% +about this was posed by The Economist + + + align:start position:0% +about this was posed by The Economist +Arthur + + align:start position:0% +Arthur + + + align:start position:0% +Arthur +Oaken about 40 50 years ago God it must + + align:start position:0% +Oaken about 40 50 years ago God it must + + + align:start position:0% +Oaken about 40 50 years ago God it must +be 50 years ago + + align:start position:0% +be 50 years ago + + + align:start position:0% +be 50 years ago +now Arthur Oaken + + align:start position:0% +now Arthur Oaken + + + align:start position:0% +now Arthur Oaken +OK posed the example of the Leaky bucket + + align:start position:0% +OK posed the example of the Leaky bucket + + + align:start position:0% +OK posed the example of the Leaky bucket +which is the best way to think about + + align:start position:0% +which is the best way to think about + + + align:start position:0% +which is the best way to think about +redistribution he said imagine the way + + align:start position:0% +redistribution he said imagine the way + + + align:start position:0% +redistribution he said imagine the way +imagine a society with the rich people + + align:start position:0% +imagine a society with the rich people + + + align:start position:0% +imagine a society with the rich people +and poor people and imagine the way we + + align:start position:0% +and poor people and imagine the way we + + + align:start position:0% +and poor people and imagine the way we +redistributed from rich people to poor + + align:start position:0% +redistributed from rich people to poor + + + align:start position:0% +redistributed from rich people to poor +people was by literally the rich people + + align:start position:0% +people was by literally the rich people + + + align:start position:0% +people was by literally the rich people +putting money in a bucket then someone + + align:start position:0% +putting money in a bucket then someone + + + align:start position:0% +putting money in a bucket then someone +carries that bucket and dumps it out in + + align:start position:0% +carries that bucket and dumps it out in + + + align:start position:0% +carries that bucket and dumps it out in +front of the poor people the simplest + + align:start position:0% +front of the poor people the simplest + + + align:start position:0% +front of the poor people the simplest +possible view of distribution and we + + align:start position:0% +possible view of distribution and we + + + align:start position:0% +possible view of distribution and we +probably and so Arthur Oak's question + + align:start position:0% +probably and so Arthur Oak's question + + + align:start position:0% +probably and so Arthur Oak's question +was imagine simple world where a rich + + align:start position:0% +was imagine simple world where a rich + + + align:start position:0% +was imagine simple world where a rich +person puts in a dollar someone carries + + align:start position:0% +person puts in a dollar someone carries + + + align:start position:0% +person puts in a dollar someone carries +over and gives that dollar to a poor + + align:start position:0% +over and gives that dollar to a poor + + + align:start position:0% +over and gives that dollar to a poor +person how many of us would favor that + + align:start position:0% +person how many of us would favor that + + + align:start position:0% +person how many of us would favor that +probably most of us probably most of us + + align:start position:0% +probably most of us probably most of us + + + align:start position:0% +probably most of us probably most of us +would think that the rich person would + + align:start position:0% +would think that the rich person would + + + align:start position:0% +would think that the rich person would +miss the dollar + + align:start position:0% +miss the dollar + + + align:start position:0% +miss the dollar +less than the poor person would value + + align:start position:0% +less than the poor person would value + + + align:start position:0% +less than the poor person would value +the dollar so probably most of us would + + align:start position:0% +the dollar so probably most of us would + + + align:start position:0% +the dollar so probably most of us would +think that if you could take a dollar + + align:start position:0% +think that if you could take a dollar + + + align:start position:0% +think that if you could take a dollar +from the rich and give it to the poor + + align:start position:0% +from the rich and give it to the poor + + + align:start position:0% +from the rich and give it to the poor +that's a good thing to + + align:start position:0% +that's a good thing to + + + align:start position:0% +that's a good thing to +do now Oak can ask but what if the + + align:start position:0% +do now Oak can ask but what if the + + + align:start position:0% +do now Oak can ask but what if the +bucket was leaky what if along the money + + align:start position:0% +bucket was leaky what if along the money + + + align:start position:0% +bucket was leaky what if along the money +along the way some of the money leaked + + align:start position:0% +along the way some of the money leaked + + + align:start position:0% +along the way some of the money leaked +out so the dollar you took from the rich + + align:start position:0% +out so the dollar you took from the rich + + + align:start position:0% +out so the dollar you took from the rich +became less than a Dollar by time I got + + align:start position:0% +became less than a Dollar by time I got + + + align:start position:0% +became less than a Dollar by time I got +to the + + align:start position:0% +to the + + + align:start position:0% +to the +poor what if it was 90 cents 70 cents 50 + + align:start position:0% +poor what if it was 90 cents 70 cents 50 + + + align:start position:0% +poor what if it was 90 cents 70 cents 50 +cents 30 Cent 10 cents or Nothing At + + align:start position:0% +cents 30 Cent 10 cents or Nothing At + + + align:start position:0% +cents 30 Cent 10 cents or Nothing At +what point do you stop wanting to make + + align:start position:0% +what point do you stop wanting to make + + + align:start position:0% +what point do you stop wanting to make +that + + align:start position:0% +that + + + align:start position:0% +that +transfer like I said for most of us if I + + align:start position:0% +transfer like I said for most of us if I + + + align:start position:0% +transfer like I said for most of us if I +said to you you could take a dollar from + + align:start position:0% +said to you you could take a dollar from + + + align:start position:0% +said to you you could take a dollar from +a very rich person give to a very poor + + align:start position:0% +a very rich person give to a very poor + + + align:start position:0% +a very rich person give to a very poor +person you'd say well that seems like a + + align:start position:0% +person you'd say well that seems like a + + + align:start position:0% +person you'd say well that seems like a +good deal what if I say get a dollar for + + align:start position:0% +good deal what if I say get a dollar for + + + align:start position:0% +good deal what if I say get a dollar for +a very rich person and give 50 cents to + + align:start position:0% +a very rich person and give 50 cents to + + + align:start position:0% +a very rich person and give 50 cents to +a very poor person is that a good deal + + align:start position:0% +a very poor person is that a good deal + + + align:start position:0% +a very poor person is that a good deal +that depends that depends on how you + + align:start position:0% +that depends that depends on how you + + + align:start position:0% +that depends that depends on how you +feel about the relative value of money + + align:start position:0% +feel about the relative value of money + + + align:start position:0% +feel about the relative value of money +in the hands of the rich and the poor it + + align:start position:0% +in the hands of the rich and the poor it + + + align:start position:0% +in the hands of the rich and the poor it +becomes a harder question and and that + + align:start position:0% +becomes a harder question and and that + + + align:start position:0% +becomes a harder question and and that +is the equity efficiency tradeoff if you + + align:start position:0% +is the equity efficiency tradeoff if you + + + align:start position:0% +is the equity efficiency tradeoff if you +can redistribute shares of the pie + + align:start position:0% +can redistribute shares of the pie + + + align:start position:0% +can redistribute shares of the pie +without shrinking the pie we probably + + align:start position:0% +without shrinking the pie we probably + + + align:start position:0% +without shrinking the pie we probably +would be in favor of that but once it + + align:start position:0% +would be in favor of that but once it + + + align:start position:0% +would be in favor of that but once it +involves shrinking the + + align:start position:0% +involves shrinking the + + + align:start position:0% +involves shrinking the +pie maybe it's not such a good idea or + + align:start position:0% +pie maybe it's not such a good idea or + + + align:start position:0% +pie maybe it's not such a good idea or +maybe it is maybe even if the dollar + + align:start position:0% +maybe it is maybe even if the dollar + + + align:start position:0% +maybe it is maybe even if the dollar +from the rich becomes nothing to the + + align:start position:0% +from the rich becomes nothing to the + + + align:start position:0% +from the rich becomes nothing to the +poor you'll still favor it because you + + align:start position:0% +poor you'll still favor it because you + + + align:start position:0% +poor you'll still favor it because you +think inherently there's uh there's a + + align:start position:0% +think inherently there's uh there's a + + + align:start position:0% +think inherently there's uh there's a +problem with + + align:start position:0% +problem with + + + align:start position:0% +problem with +inequality so ultimately the question we + + align:start position:0% +inequality so ultimately the question we + + + align:start position:0% +inequality so ultimately the question we +want to think about is where what's the + + align:start position:0% +want to think about is where what's the + + + align:start position:0% +want to think about is where what's the +leak that you accept in your bucket + + align:start position:0% +leak that you accept in your bucket + + + align:start position:0% +leak that you accept in your bucket +what's the leak that you're willing to + + align:start position:0% +what's the leak that you're willing to + + + align:start position:0% +what's the leak that you're willing to +accept to transfer money and we're going + + align:start position:0% +accept to transfer money and we're going + + + align:start position:0% +accept to transfer money and we're going +to discuss that issue in four steps in + + align:start position:0% +to discuss that issue in four steps in + + + align:start position:0% +to discuss that issue in four steps in +the next two + + align:start position:0% +the next two + + + align:start position:0% +the next two +lectures the first step is we're going + + align:start position:0% +lectures the first step is we're going + + + align:start position:0% +lectures the first step is we're going +to ask about social + + align:start position:0% + + + + align:start position:0% + +valuation of + + align:start position:0% +valuation of + + + align:start position:0% +valuation of +transfers how does how do we + + align:start position:0% +transfers how does how do we + + + align:start position:0% +transfers how does how do we +think the issue we've avoided through + + align:start position:0% +think the issue we've avoided through + + + align:start position:0% +think the issue we've avoided through +this whole course how do we think within + + align:start position:0% +this whole course how do we think within + + + align:start position:0% +this whole course how do we think within +our base economic framework about how + + align:start position:0% +our base economic framework about how + + + align:start position:0% +our base economic framework about how +Society feels about taking money from a + + align:start position:0% +Society feels about taking money from a + + + align:start position:0% +Society feels about taking money from a +and giving it to + + align:start position:0% + + + + align:start position:0% + +B the Second Step we're going to ask is + + align:start position:0% +B the Second Step we're going to ask is + + + align:start position:0% +B the Second Step we're going to ask is +what is the actual inequality that + + align:start position:0% +what is the actual inequality that + + + align:start position:0% +what is the actual inequality that +exists in + + align:start position:0% +exists in + + + align:start position:0% +exists in +society what are the facts on who has + + align:start position:0% +society what are the facts on who has + + + align:start position:0% +society what are the facts on who has +the dollars what are the motivations for + + align:start position:0% +the dollars what are the motivations for + + + align:start position:0% +the dollars what are the motivations for +potentially addressing these + + align:start position:0% +potentially addressing these + + + align:start position:0% +potentially addressing these +distributional + + align:start position:0% +distributional + + + align:start position:0% +distributional +issues the third thing we're to ask is + + align:start position:0% +issues the third thing we're to ask is + + + align:start position:0% +issues the third thing we're to ask is +where does the leakage what are the + + align:start position:0% +where does the leakage what are the + + + align:start position:0% +where does the leakage what are the +sources of leak + + align:start position:0% +sources of leak + + + align:start position:0% +sources of leak +leakage where does the leakage come + + align:start position:0% +leakage where does the leakage come + + + align:start position:0% +leakage where does the leakage come +from where do the leaks that where do + + align:start position:0% +from where do the leaks that where do + + + align:start position:0% +from where do the leaks that where do +the leaks that that leaky bucket come + + align:start position:0% +the leaks that that leaky bucket come + + + align:start position:0% +the leaks that that leaky bucket come +from why is it + + align:start position:0% +from why is it + + + align:start position:0% +from why is it +leaky and then finally we're going to + + align:start position:0% +leaky and then finally we're going to + + + align:start position:0% +leaky and then finally we're going to +ask about transfer + + align:start position:0% + + + + align:start position:0% + +policy how does government actually go + + align:start position:0% +policy how does government actually go + + + align:start position:0% +policy how does government actually go +about taking money from some people and + + align:start position:0% +about taking money from some people and + + + align:start position:0% +about taking money from some people and +giving it to + + align:start position:0% +giving it to + + + align:start position:0% +giving it to +others those are the four steps we're + + align:start position:0% +others those are the four steps we're + + + align:start position:0% +others those are the four steps we're +going to go through we'll get through + + align:start position:0% +going to go through we'll get through + + + align:start position:0% +going to go through we'll get through +the first three today and F focus on the + + align:start position:0% +the first three today and F focus on the + + + align:start position:0% +the first three today and F focus on the +last one on + + align:start position:0% +last one on + + + align:start position:0% +last one on +Monday so let's start with the first one + + align:start position:0% +Monday so let's start with the first one + + + align:start position:0% +Monday so let's start with the first one +which + + align:start position:0% +which + + + align:start position:0% +which +is how do we think + + align:start position:0% +is how do we think + + + align:start position:0% +is how do we think +about + + align:start position:0% +about + + + align:start position:0% +about +social + + align:start position:0% +social + + + align:start position:0% +social +welfare of + + align:start position:0% + + + + align:start position:0% + +allocation so far we've just thought + + align:start position:0% +allocation so far we've just thought + + + align:start position:0% +allocation so far we've just thought +about the social welfare of total if + + align:start position:0% +about the social welfare of total if + + + align:start position:0% +about the social welfare of total if +total efficiency we haven't thought + + align:start position:0% +total efficiency we haven't thought + + + align:start position:0% +total efficiency we haven't thought +about + + align:start position:0% +about + + + align:start position:0% +about +allocation imagine we with many + + align:start position:0% +allocation imagine we with many + + + align:start position:0% +allocation imagine we with many +different + + align:start position:0% +different + + + align:start position:0% +different +outcomes different levels of efficiency + + align:start position:0% +outcomes different levels of efficiency + + + align:start position:0% +outcomes different levels of efficiency +but also different levels of equity a + + align:start position:0% +but also different levels of equity a + + + align:start position:0% +but also different levels of equity a +world with different with with buckets + + align:start position:0% +world with different with with buckets + + + align:start position:0% +world with different with with buckets +that are different leakages and + + align:start position:0% +that are different leakages and + + + align:start position:0% +that are different leakages and +different amounts of money going to + + align:start position:0% +different amounts of money going to + + + align:start position:0% +different amounts of money going to +different people how would we compare + + align:start position:0% +different people how would we compare + + + align:start position:0% +different people how would we compare +them well here we're going to use the + + align:start position:0% +them well here we're going to use the + + + align:start position:0% +them well here we're going to use the +same tool we started with in lecture + + align:start position:0% +same tool we started with in lecture + + + align:start position:0% +same tool we started with in lecture +two how do we think about any valuing + + align:start position:0% +two how do we think about any valuing + + + align:start position:0% +two how do we think about any valuing +any combination of goods from a consumer + + align:start position:0% +any combination of goods from a consumer + + + align:start position:0% +any combination of goods from a consumer +well we say they have utility function + + align:start position:0% +well we say they have utility function + + + align:start position:0% +well we say they have utility function +and we say how do those different + + align:start position:0% +and we say how do those different + + + align:start position:0% +and we say how do those different +combinations of good enter the + + align:start position:0% +combinations of good enter the + + + align:start position:0% +combinations of good enter the +utility well to think about socially + + align:start position:0% +utility well to think about socially + + + align:start position:0% +utility well to think about socially +optimal + + align:start position:0% +optimal + + + align:start position:0% +optimal +allocation we're going to think about a + + align:start position:0% +allocation we're going to think about a + + + align:start position:0% +allocation we're going to think about a +social utility function or what we're + + align:start position:0% +social utility function or what we're + + + align:start position:0% +social utility function or what we're +going to call a social welfare function + + align:start position:0% +going to call a social welfare function + + + align:start position:0% +going to call a social welfare function +we're going to say look if we want to + + align:start position:0% +we're going to say look if we want to + + + align:start position:0% +we're going to say look if we want to +think about the value of goods in the + + align:start position:0% +think about the value of goods in the + + + align:start position:0% +think about the value of goods in the +hands of person a versus B we have to + + align:start position:0% +hands of person a versus B we have to + + + align:start position:0% +hands of person a versus B we have to +write down a mathematical function for + + align:start position:0% +write down a mathematical function for + + + align:start position:0% +write down a mathematical function for +how Society feels about the value of + + align:start position:0% +how Society feels about the value of + + + align:start position:0% +how Society feels about the value of +goods in the hands of person A or B that + + align:start position:0% +goods in the hands of person A or B that + + + align:start position:0% +goods in the hands of person A or B that +is Loosely a utility function for + + align:start position:0% +is Loosely a utility function for + + + align:start position:0% +is Loosely a utility function for +society essentially + + align:start position:0% +society essentially + + + align:start position:0% +society essentially +aggregation of each individual's utility + + align:start position:0% +aggregation of each individual's utility + + + align:start position:0% +aggregation of each individual's utility +so the function per utility one utility + + align:start position:0% +so the function per utility one utility + + + align:start position:0% +so the function per utility one utility +two all the way up to utility 3 150 + + align:start position:0% +two all the way up to utility 3 150 + + + align:start position:0% +two all the way up to utility 3 150 +million okay so this the social welfare + + align:start position:0% +million okay so this the social welfare + + + align:start position:0% +million okay so this the social welfare +function for the United States is + + align:start position:0% +function for the United States is + + + align:start position:0% +function for the United States is +literally some aggregation some + + align:start position:0% +literally some aggregation some + + + align:start position:0% +literally some aggregation some +mathematical function of everyone's + + align:start position:0% +mathematical function of everyone's + + + align:start position:0% +mathematical function of everyone's +utility and you should be able to see + + align:start position:0% +utility and you should be able to see + + + align:start position:0% +utility and you should be able to see +for a given mathematical + + align:start position:0% +for a given mathematical + + + align:start position:0% +for a given mathematical +function I can then evaluate how I feel + + align:start position:0% +function I can then evaluate how I feel + + + align:start position:0% +function I can then evaluate how I feel +about transfers because I can look at + + align:start position:0% +about transfers because I can look at + + + align:start position:0% +about transfers because I can look at +what those transfers done each person's + + align:start position:0% +what those transfers done each person's + + + align:start position:0% +what those transfers done each person's +utility I can use this function to + + align:start position:0% +utility I can use this function to + + + align:start position:0% +utility I can use this function to +translate to new social + + align:start position:0% +translate to new social + + + align:start position:0% +translate to new social +allocation okay so to see that let's + + align:start position:0% +allocation okay so to see that let's + + + align:start position:0% +allocation okay so to see that let's +look at figure + + align:start position:0% +look at figure + + + align:start position:0% +look at figure +231 these draw what we call isow welfare + + align:start position:0% +231 these draw what we call isow welfare + + + align:start position:0% +231 these draw what we call isow welfare +curves now in our two-dimensional graph + + align:start position:0% +curves now in our two-dimensional graph + + + align:start position:0% +curves now in our two-dimensional graph +the trade-off is between goods to two + + align:start position:0% +the trade-off is between goods to two + + + align:start position:0% +the trade-off is between goods to two +people Homer and Ned okay we have Homer + + align:start position:0% +people Homer and Ned okay we have Homer + + + align:start position:0% +people Homer and Ned okay we have Homer +and Ned Society consists of these two + + align:start position:0% +and Ned Society consists of these two + + + align:start position:0% +and Ned Society consists of these two +people and we want to think about how do + + align:start position:0% +people and we want to think about how do + + + align:start position:0% +people and we want to think about how do +we feel about resources in the hand of + + align:start position:0% +we feel about resources in the hand of + + + align:start position:0% +we feel about resources in the hand of +Homer versus Ned and we could say for + + align:start position:0% +Homer versus Ned and we could say for + + + align:start position:0% +Homer versus Ned and we could say for +example that we're indifferent between + + align:start position:0% +example that we're indifferent between + + + align:start position:0% +example that we're indifferent between +the allocations u1h + + align:start position:0% +the allocations u1h + + + align:start position:0% +the allocations u1h +u1n and u2h u2n say we're a different + + align:start position:0% +u1n and u2h u2n say we're a different + + + align:start position:0% +u1n and u2h u2n say we're a different +between Ned having a lot and Homer + + align:start position:0% +between Ned having a lot and Homer + + + align:start position:0% +between Ned having a lot and Homer +having a little or Homer having a lot + + align:start position:0% +having a little or Homer having a lot + + + align:start position:0% +having a little or Homer having a lot +net having a little then they'd be on + + align:start position:0% +net having a little then they'd be on + + + align:start position:0% +net having a little then they'd be on +the same isow welfare curve but by the + + align:start position:0% +the same isow welfare curve but by the + + + align:start position:0% +the same isow welfare curve but by the +Moors better principle we're certainly + + align:start position:0% +Moors better principle we're certainly + + + align:start position:0% +Moors better principle we're certainly +happy as a society with both having + + align:start position:0% +happy as a society with both having + + + align:start position:0% +happy as a society with both having +more just like any indifference curve + + align:start position:0% +more just like any indifference curve + + + align:start position:0% +more just like any indifference curve +the ISO Wells our curves the further out + + align:start position:0% +the ISO Wells our curves the further out + + + align:start position:0% +the ISO Wells our curves the further out +the better off we + + align:start position:0% +the better off we + + + align:start position:0% +the better off we +are okay so basically um this is + + align:start position:0% +are okay so basically um this is + + + align:start position:0% +are okay so basically um this is +essentially a + + align:start position:0% +essentially a + + + align:start position:0% +essentially a +mapping of a social welfare curve of a + + align:start position:0% +mapping of a social welfare curve of a + + + align:start position:0% +mapping of a social welfare curve of a +social welfare function just like + + align:start position:0% +social welfare function just like + + + align:start position:0% +social welfare function just like +utility function gives us an + + align:start position:0% +utility function gives us an + + + align:start position:0% +utility function gives us an +indifference curve + + align:start position:0% +indifference curve + + + align:start position:0% +indifference curve +mapping a social welfare function gives + + align:start position:0% +mapping a social welfare function gives + + + align:start position:0% +mapping a social welfare function gives +us an isow welfare curve + + align:start position:0% +us an isow welfare curve + + + align:start position:0% +us an isow welfare curve +mapping so then we just simply have to + + align:start position:0% +mapping so then we just simply have to + + + align:start position:0% +mapping so then we just simply have to +ask what does a social welfare function + + align:start position:0% +ask what does a social welfare function + + + align:start position:0% +ask what does a social welfare function +look like we talked about what utility + + align:start position:0% +look like we talked about what utility + + + align:start position:0% +look like we talked about what utility +functions look like we talked about + + align:start position:0% +functions look like we talked about + + + align:start position:0% +functions look like we talked about +their General print properties and that + + align:start position:0% +their General print properties and that + + + align:start position:0% +their General print properties and that +common example we use of the square root + + align:start position:0% +common example we use of the square root + + + align:start position:0% +common example we use of the square root +utility function but we said basically + + align:start position:0% +utility function but we said basically + + + align:start position:0% +utility function but we said basically +we can use a broad class of functions + + align:start position:0% +we can use a broad class of functions + + + align:start position:0% +we can use a broad class of functions +you've seen on problem sets and exams a + + align:start position:0% +you've seen on problem sets and exams a + + + align:start position:0% +you've seen on problem sets and exams a +broad class utility + + align:start position:0% +broad class utility + + + align:start position:0% +broad class utility +functions what about social welfare + + align:start position:0% +functions what about social welfare + + + align:start position:0% +functions what about social welfare +function social welfare functions + + align:start position:0% +function social welfare functions + + + align:start position:0% +function social welfare functions +typically we work in economics with a + + align:start position:0% +typically we work in economics with a + + + align:start position:0% +typically we work in economics with a +couple of different forms of social + + align:start position:0% +couple of different forms of social + + + align:start position:0% +couple of different forms of social +welfare + + align:start position:0% +welfare + + + align:start position:0% +welfare +functions the most common form of social + + align:start position:0% +functions the most common form of social + + + align:start position:0% +functions the most common form of social +welfare function is what we call + + align:start position:0% + + + + align:start position:0% + +utilitarian social welfare function the + + align:start position:0% +utilitarian social welfare function the + + + align:start position:0% +utilitarian social welfare function the +utilitarian social welfare function + + align:start position:0% +utilitarian social welfare function + + + align:start position:0% +utilitarian social welfare function +simply poses that social + + align:start position:0% +simply poses that social + + + align:start position:0% +simply poses that social +welfare is simply the linear sum of + + align:start position:0% +welfare is simply the linear sum of + + + align:start position:0% +welfare is simply the linear sum of +utilities U1 plus U2 plus dot do D plus + + align:start position:0% +utilities U1 plus U2 plus dot do D plus + + + align:start position:0% +utilities U1 plus U2 plus dot do D plus +u350 + + align:start position:0% + + + + align:start position:0% + +million that is utilitarian it's + + align:start position:0% +million that is utilitarian it's + + + align:start position:0% +million that is utilitarian it's +literally I I don't know I don't I have + + align:start position:0% +literally I I don't know I don't I have + + + align:start position:0% +literally I I don't know I don't I have +no base Society for caring any more + + align:start position:0% +no base Society for caring any more + + + align:start position:0% +no base Society for caring any more +about one person than anyone else just + + align:start position:0% +about one person than anyone else just + + + align:start position:0% +about one person than anyone else just +going to add their + + align:start position:0% +going to add their + + + align:start position:0% +going to add their +utilities the person this guy named + + align:start position:0% +utilities the person this guy named + + + align:start position:0% +utilities the person this guy named +Jeremy Bentham a famous British + + align:start position:0% +Jeremy Bentham a famous British + + + align:start position:0% +Jeremy Bentham a famous British +philosopher uh couple things to not + + align:start position:0% +philosopher uh couple things to not + + + align:start position:0% +philosopher uh couple things to not +about Jeremy Bentham first of all he + + align:start position:0% +about Jeremy Bentham first of all he + + + align:start position:0% +about Jeremy Bentham first of all he +also invented the modern he invented a + + align:start position:0% +also invented the modern he invented a + + + align:start position:0% +also invented the modern he invented a +modern design of Prisons which is quite + + align:start position:0% +modern design of Prisons which is quite + + + align:start position:0% +modern design of Prisons which is quite +interesting he was a broad thinkinking + + align:start position:0% +interesting he was a broad thinkinking + + + align:start position:0% +interesting he was a broad thinkinking +philosopher he also um when he died his + + align:start position:0% +philosopher he also um when he died his + + + align:start position:0% +philosopher he also um when he died his +stuffed body with the head separated was + + align:start position:0% +stuffed body with the head separated was + + + align:start position:0% +stuffed body with the head separated was +on display at University College London + + align:start position:0% +on display at University College London + + + align:start position:0% +on display at University College London +um until it turned out students would + + align:start position:0% +um until it turned out students would + + + align:start position:0% +um until it turned out students would +take the head out and play soccer with + + align:start position:0% +take the head out and play soccer with + + + align:start position:0% +take the head out and play soccer with +it so they no longer do that so um he's + + align:start position:0% +it so they no longer do that so um he's + + + align:start position:0% +it so they no longer do that so um he's +a famous philosopher cample the + + align:start position:0% +a famous philosopher cample the + + + align:start position:0% +a famous philosopher cample the +utilitarian social war function it's + + align:start position:0% +utilitarian social war function it's + + + align:start position:0% +utilitarian social war function it's +sort of a natural starting + + align:start position:0% +sort of a natural starting + + + align:start position:0% +sort of a natural starting +point and if you think about it it's not + + align:start position:0% +point and if you think about it it's not + + + align:start position:0% +point and if you think about it it's not +really sort of cons you wouldn't look at + + align:start position:0% +really sort of cons you wouldn't look at + + + align:start position:0% +really sort of cons you wouldn't look at +this this is conservative or liberal + + align:start position:0% +this this is conservative or liberal + + + align:start position:0% +this this is conservative or liberal +right you look at to say oh that's a + + align:start position:0% +right you look at to say oh that's a + + + align:start position:0% +right you look at to say oh that's a +lefty or righty it's just it's neutral + + align:start position:0% +lefty or righty it's just it's neutral + + + align:start position:0% +lefty or righty it's just it's neutral +it's just saying look I care about + + align:start position:0% +it's just saying look I care about + + + align:start position:0% +it's just saying look I care about +everyone equally that seems pretty + + align:start position:0% +everyone equally that seems pretty + + + align:start position:0% +everyone equally that seems pretty +neutral and yet this neutral social + + align:start position:0% +neutral and yet this neutral social + + + align:start position:0% +neutral and yet this neutral social +utility function has radical + + align:start position:0% +utility function has radical + + + align:start position:0% +utility function has radical +implications for + + align:start position:0% +implications for + + + align:start position:0% +implications for +distribution in particular it says we + + align:start position:0% +distribution in particular it says we + + + align:start position:0% +distribution in particular it says we +should always + + align:start position:0% +should always + + + align:start position:0% +should always +transfer between any two + + align:start position:0% +transfer between any two + + + align:start position:0% +transfer between any two +people if the transfer makes person two + + align:start position:0% +people if the transfer makes person two + + + align:start position:0% +people if the transfer makes person two +happier than it makes person one + + align:start position:0% +happier than it makes person one + + + align:start position:0% +happier than it makes person one +sad that means we're indifferent between + + align:start position:0% +sad that means we're indifferent between + + + align:start position:0% +sad that means we're indifferent between +one udle to you and to Bill + + align:start position:0% +one udle to you and to Bill + + + align:start position:0% +one udle to you and to Bill +Gates now that sounds kind of + + align:start position:0% +Gates now that sounds kind of + + + align:start position:0% +Gates now that sounds kind of +conservative we're indifferent like + + align:start position:0% +conservative we're indifferent like + + + align:start position:0% +conservative we're indifferent like +you're poor than Bill Gates we should + + align:start position:0% +you're poor than Bill Gates we should + + + align:start position:0% +you're poor than Bill Gates we should +care more about you but remember I said + + align:start position:0% +care more about you but remember I said + + + align:start position:0% +care more about you but remember I said +we're indiff in one udle between you and + + align:start position:0% +we're indiff in one udle between you and + + + align:start position:0% +we're indiff in one udle between you and +Bill Gates that doesn't mean we're + + align:start position:0% +Bill Gates that doesn't mean we're + + + align:start position:0% +Bill Gates that doesn't mean we're +differing than $1 doll between you and + + align:start position:0% +differing than $1 doll between you and + + + align:start position:0% +differing than $1 doll between you and +Bill + + align:start position:0% +Bill + + + align:start position:0% +Bill +Gates okay indeed who would we rather + + align:start position:0% +Gates okay indeed who would we rather + + + align:start position:0% +Gates okay indeed who would we rather +with this social work function who would + + align:start position:0% +with this social work function who would + + + align:start position:0% +with this social work function who would +we rather have the dollar you or Bill + + align:start position:0% +we rather have the dollar you or Bill + + + align:start position:0% +we rather have the dollar you or Bill +Gates and why let's say there's a dollar + + align:start position:0% +Gates and why let's say there's a dollar + + + align:start position:0% +Gates and why let's say there's a dollar +up for grabs with the utilit social + + align:start position:0% +up for grabs with the utilit social + + + align:start position:0% +up for grabs with the utilit social +welfare function would social welfare be + + align:start position:0% +welfare function would social welfare be + + + align:start position:0% +welfare function would social welfare be +higher if you got the dollar or Bill + + align:start position:0% +higher if you got the dollar or Bill + + + align:start position:0% +higher if you got the dollar or Bill +Gates got the dollar and + + align:start position:0% +Gates got the dollar and + + + align:start position:0% +Gates got the dollar and +Y + + align:start position:0% +Y + + + align:start position:0% +Y +yeah L the margin of dollars higher to + + align:start position:0% +yeah L the margin of dollars higher to + + + align:start position:0% +yeah L the margin of dollars higher to +you to you and less to Bill Gates what + + align:start position:0% +you to you and less to Bill Gates what + + + align:start position:0% +you to you and less to Bill Gates what +this says if you maximize this if you + + align:start position:0% +this says if you maximize this if you + + + align:start position:0% +this says if you maximize this if you +maximize this this implies you should + + align:start position:0% +maximize this this implies you should + + + align:start position:0% +maximize this this implies you should +set the Marge utility of all individuals + + align:start position:0% + + + + align:start position:0% + +equal I'm put 350 million because 350 + + align:start position:0% +equal I'm put 350 million because 350 + + + align:start position:0% +equal I'm put 350 million because 350 +million people in America okay this + + align:start position:0% +million people in America okay this + + + align:start position:0% +million people in America okay this +implies you should put the margin + + align:start position:0% +implies you should put the margin + + + align:start position:0% +implies you should put the margin +utility of every person equal that's a + + align:start position:0% +utility of every person equal that's a + + + align:start position:0% +utility of every person equal that's a +pretty radical implication + + align:start position:0% +pretty radical implication + + + align:start position:0% +pretty radical implication +that says literally you should reute + + align:start position:0% +that says literally you should reute + + + align:start position:0% +that says literally you should reute +money until everybody values the dollar + + align:start position:0% +money until everybody values the dollar + + + align:start position:0% +money until everybody values the dollar +the next dollar the same that say you + + align:start position:0% +the next dollar the same that say you + + + align:start position:0% +the next dollar the same that say you +should massively redistribute from the + + align:start position:0% +should massively redistribute from the + + + align:start position:0% +should massively redistribute from the +rich to the + + align:start position:0% +rich to the + + + align:start position:0% +rich to the +poor right because the rich value the + + align:start position:0% +poor right because the rich value the + + + align:start position:0% +poor right because the rich value the +next dollar way less than the poor Bill + + align:start position:0% +next dollar way less than the poor Bill + + + align:start position:0% +next dollar way less than the poor Bill +Gates couldn't give a about the + + align:start position:0% +Gates couldn't give a about the + + + align:start position:0% +Gates couldn't give a about the +next dollar where some poor homeless guy + + align:start position:0% +next dollar where some poor homeless guy + + + align:start position:0% +next dollar where some poor homeless guy +mean could be difference between a hot + + align:start position:0% +mean could be difference between a hot + + + align:start position:0% +mean could be difference between a hot +meal and not having a hot meal today on + + align:start position:0% +meal and not having a hot meal today on + + + align:start position:0% +meal and not having a hot meal today on +a cold day so clearly this is fairly + + align:start position:0% +a cold day so clearly this is fairly + + + align:start position:0% +a cold day so clearly this is fairly +this suggests that we dimin as long as + + align:start position:0% +this suggests that we dimin as long as + + + align:start position:0% +this suggests that we dimin as long as +there's diminishing margin + + align:start position:0% +there's diminishing margin + + + align:start position:0% +there's diminishing margin +utility you should have fairly strong + + align:start position:0% +utility you should have fairly strong + + + align:start position:0% +utility you should have fairly strong +preferences to redistribute from the + + align:start position:0% +preferences to redistribute from the + + + align:start position:0% +preferences to redistribute from the +rich to the poor despite the fact that + + align:start position:0% +rich to the poor despite the fact that + + + align:start position:0% +rich to the poor despite the fact that +when I wrote this you didn't look at it + + align:start position:0% +when I wrote this you didn't look at it + + + align:start position:0% +when I wrote this you didn't look at it +and say wow this is some Lefty crazy + + align:start position:0% +and say wow this is some Lefty crazy + + + align:start position:0% +and say wow this is some Lefty crazy +utility function it has sort of Lefty + + align:start position:0% +utility function it has sort of Lefty + + + align:start position:0% +utility function it has sort of Lefty +implications right it says we should + + align:start position:0% +implications right it says we should + + + align:start position:0% +implications right it says we should +redistribute strongly from the rich to + + align:start position:0% +redistribute strongly from the rich to + + + align:start position:0% +redistribute strongly from the rich to +the poor it sort of makes sense the rich + + align:start position:0% +the poor it sort of makes sense the rich + + + align:start position:0% +the poor it sort of makes sense the rich +care about the money less than the poor + + align:start position:0% +care about the money less than the poor + + + align:start position:0% +care about the money less than the poor +care about and that's your sort of + + align:start position:0% +care about and that's your sort of + + + align:start position:0% +care about and that's your sort of +underlying intuition why we all start + + align:start position:0% +underlying intuition why we all start + + + align:start position:0% +underlying intuition why we all start +with this notion that redistribution + + align:start position:0% +with this notion that redistribution + + + align:start position:0% +with this notion that redistribution +makes sense indeed this goes further if + + align:start position:0% +makes sense indeed this goes further if + + + align:start position:0% +makes sense indeed this goes further if +individuals are all + + align:start position:0% +individuals are all + + + align:start position:0% +individuals are all +identical this if individual are all + + align:start position:0% +identical this if individual are all + + + align:start position:0% +identical this if individual are all +this suggests we should have an equal + + align:start position:0% +this suggests we should have an equal + + + align:start position:0% +this suggests we should have an equal +distribution of income a pretty radical + + align:start position:0% +distribution of income a pretty radical + + + align:start position:0% +distribution of income a pretty radical +concept that's never been achieved + + align:start position:0% +concept that's never been achieved + + + align:start position:0% +concept that's never been achieved +anywhere in history by any + + align:start position:0% +anywhere in history by any + + + align:start position:0% +anywhere in history by any +society if individuals are all identical + + align:start position:0% +society if individuals are all identical + + + align:start position:0% +society if individuals are all identical +this says we should have an equal + + align:start position:0% +this says we should have an equal + + + align:start position:0% +this says we should have an equal +distribution of income pretty radical + + align:start position:0% +distribution of income pretty radical + + + align:start position:0% +distribution of income pretty radical +from a pretty straightforward + + align:start position:0% +from a pretty straightforward + + + align:start position:0% +from a pretty straightforward +concept now in fact to many + + align:start position:0% +concept now in fact to many + + + align:start position:0% +concept now in fact to many +people this is actually a very + + align:start position:0% +people this is actually a very + + + align:start position:0% +people this is actually a very +conservative approach to think about + + align:start position:0% +conservative approach to think about + + + align:start position:0% +conservative approach to think about +about income distribution indeed + + align:start position:0% +about income distribution indeed + + + align:start position:0% +about income distribution indeed +typically conservatives often start with + + align:start position:0% +typically conservatives often start with + + + align:start position:0% +typically conservatives often start with +this point many people on the left start + + align:start position:0% +this point many people on the left start + + + align:start position:0% +this point many people on the left start +with an alternative approach what's + + align:start position:0% +with an alternative approach what's + + + align:start position:0% +with an alternative approach what's +called a rollan w r awl rollan social + + align:start position:0% +called a rollan w r awl rollan social + + + align:start position:0% +called a rollan w r awl rollan social +welfare function named up philosopher + + align:start position:0% +welfare function named up philosopher + + + align:start position:0% +welfare function named up philosopher +John rolls famous philosopher at + + align:start position:0% +John rolls famous philosopher at + + + align:start position:0% +John rolls famous philosopher at +Harvard RS said that utility that the + + align:start position:0% +Harvard RS said that utility that the + + + align:start position:0% +Harvard RS said that utility that the +social welfare of society should be + + align:start position:0% +social welfare of society should be + + + align:start position:0% +social welfare of society should be +measured as the men of everyone's + + align:start position:0% +measured as the men of everyone's + + + align:start position:0% +measured as the men of everyone's +utility that a society should be + + align:start position:0% +utility that a society should be + + + align:start position:0% +utility that a society should be +measured by the living standards of its + + align:start position:0% +measured by the living standards of its + + + align:start position:0% +measured by the living standards of its +worst off + + align:start position:0% +worst off + + + align:start position:0% +worst off +member that as Society we should care + + align:start position:0% +member that as Society we should care + + + align:start position:0% +member that as Society we should care +about those who are poorly off and + + align:start position:0% +about those who are poorly off and + + + align:start position:0% +about those who are poorly off and +Society should be measured by the + + align:start position:0% +Society should be measured by the + + + align:start position:0% +Society should be measured by the +utility of the worst off member that + + align:start position:0% +utility of the worst off member that + + + align:start position:0% +utility of the worst off member that +sort of has some appeal okay we should + + align:start position:0% +sort of has some appeal okay we should + + + align:start position:0% +sort of has some appeal okay we should +care about these people but it's + + align:start position:0% +care about these people but it's + + + align:start position:0% +care about these people but it's +incredibly extreme in its implications + + align:start position:0% +incredibly extreme in its implications + + + align:start position:0% +incredibly extreme in its implications +think about it for a second let's say + + align:start position:0% +think about it for a second let's say + + + align:start position:0% +think about it for a second let's say +say there's a society consists of + + align:start position:0% +say there's a society consists of + + + align:start position:0% +say there's a society consists of +everyone in the world everyone in the US + + align:start position:0% +everyone in the world everyone in the US + + + align:start position:0% +everyone in the world everyone in the US +has + + align:start position:0% +has + + + align:start position:0% +has +$40,000 except one guy has a billion + + align:start position:0% +$40,000 except one guy has a billion + + + align:start position:0% +$40,000 except one guy has a billion +dollar and one guy has + + align:start position:0% + + + + align:start position:0% + +$39,000 this says that we should be + + align:start position:0% +$39,000 this says that we should be + + + align:start position:0% +$39,000 this says that we should be +willing to take the billionaire all the + + align:start position:0% +willing to take the billionaire all the + + + align:start position:0% +willing to take the billionaire all the +way down to + + align:start position:0% +way down to + + + align:start position:0% +way down to +40,000 just to get the 39,000 guy up to + + align:start position:0% +40,000 just to get the 39,000 guy up to + + + align:start position:0% +40,000 just to get the 39,000 guy up to +40,000 that's pretty radical it says + + align:start position:0% +40,000 that's pretty radical it says + + + align:start position:0% +40,000 that's pretty radical it says +that basically we don't care about any + + align:start position:0% +that basically we don't care about any + + + align:start position:0% +that basically we don't care about any +anything people have about the minimum + + align:start position:0% +anything people have about the minimum + + + align:start position:0% +anything people have about the minimum +we just care about making sure everybody + + align:start position:0% +we just care about making sure everybody + + + align:start position:0% +we just care about making sure everybody +gets to that + + align:start position:0% +gets to that + + + align:start position:0% +gets to that +minimum so that is very that makes this + + align:start position:0% +minimum so that is very that makes this + + + align:start position:0% +minimum so that is very that makes this +look like a conservative fantasy this is + + align:start position:0% +look like a conservative fantasy this is + + + align:start position:0% +look like a conservative fantasy this is +an incredibly radical approach which + + align:start position:0% +an incredibly radical approach which + + + align:start position:0% +an incredibly radical approach which +says we should take everything from the + + align:start position:0% +says we should take everything from the + + + align:start position:0% +says we should take everything from the +rich just to make sure the poor have + + align:start position:0% +rich just to make sure the poor have + + + align:start position:0% +rich just to make sure the poor have +enough + + align:start position:0% +enough + + + align:start position:0% +enough +okay but that's that's um clearly under + + align:start position:0% +okay but that's that's um clearly under + + + align:start position:0% +okay but that's that's um clearly under +utilitarian social war function that + + align:start position:0% +utilitarian social war function that + + + align:start position:0% +utilitarian social war function that +make us bad off clearly Bill clearly is + + align:start position:0% +make us bad off clearly Bill clearly is + + + align:start position:0% +make us bad off clearly Bill clearly is +the guy who goes from a billion to + + align:start position:0% +the guy who goes from a billion to + + + align:start position:0% +the guy who goes from a billion to +40,000 is made sad than the guy goes to + + align:start position:0% +40,000 is made sad than the guy goes to + + + align:start position:0% +40,000 is made sad than the guy goes to +39 to 40,000 is made happier so clearly + + align:start position:0% +39 to 40,000 is made happier so clearly + + + align:start position:0% +39 to 40,000 is made happier so clearly +that would not be a proper thing to do + + align:start position:0% +that would not be a proper thing to do + + + align:start position:0% +that would not be a proper thing to do +under utilitarian social welfare + + align:start position:0% +under utilitarian social welfare + + + align:start position:0% +under utilitarian social welfare +function but it would under + + align:start position:0% + + + + align:start position:0% + +Ry now of course on the right there's a + + align:start position:0% +Ry now of course on the right there's a + + + align:start position:0% +Ry now of course on the right there's a +on the on the conservative right there's + + align:start position:0% +on the on the conservative right there's + + + align:start position:0% +on the on the conservative right there's +a crism that of both of these approaches + + align:start position:0% +a crism that of both of these approaches + + + align:start position:0% +a crism that of both of these approaches +and that + + align:start position:0% +and that + + + align:start position:0% +and that +view there's there's a criticism on the + + align:start position:0% +view there's there's a criticism on the + + + align:start position:0% +view there's there's a criticism on the +uh uh which is that basically uh the + + align:start position:0% +uh uh which is that basically uh the + + + align:start position:0% +uh uh which is that basically uh the +conservative criticism + + align:start position:0% + + + + align:start position:0% + +criticism says that + + align:start position:0% +criticism says that + + + align:start position:0% +criticism says that +basically look this whole discussion is + + align:start position:0% +basically look this whole discussion is + + + align:start position:0% +basically look this whole discussion is +misguided it says look let's say we + + align:start position:0% +misguided it says look let's say we + + + align:start position:0% +misguided it says look let's say we +started in society with everyone having + + align:start position:0% +started in society with everyone having + + + align:start position:0% +started in society with everyone having +the same amount of + + align:start position:0% +the same amount of + + + align:start position:0% +the same amount of +money let's say start everyone you and I + + align:start position:0% +money let's say start everyone you and I + + + align:start position:0% +money let's say start everyone you and I +have the same amount of money and let's + + align:start position:0% +have the same amount of money and let's + + + align:start position:0% +have the same amount of money and let's +say that you were willing as you should + + align:start position:0% +say that you were willing as you should + + + align:start position:0% +say that you were willing as you should +be willing to pay $100 to hear me + + align:start position:0% +be willing to pay $100 to hear me + + + align:start position:0% +be willing to pay $100 to hear me +lecture and so so you come in every day + + align:start position:0% +lecture and so so you come in every day + + + align:start position:0% +lecture and so so you come in every day +and you give me a $100 to you hear me + + align:start position:0% +and you give me a $100 to you hear me + + + align:start position:0% +and you give me a $100 to you hear me +lecture a + + align:start position:0% +lecture a + + + align:start position:0% +lecture a +bargain okay at the end of the semester + + align:start position:0% +bargain okay at the end of the semester + + + align:start position:0% +bargain okay at the end of the semester +I am richer or you are poorer is that + + align:start position:0% +I am richer or you are poorer is that + + + align:start position:0% +I am richer or you are poorer is that +unfair what's unfair about that you paid + + align:start position:0% +unfair what's unfair about that you paid + + + align:start position:0% +unfair what's unfair about that you paid +for something you + + align:start position:0% +for something you + + + align:start position:0% +for something you +wanted I had something you wanted and I + + align:start position:0% +wanted I had something you wanted and I + + + align:start position:0% +wanted I had something you wanted and I +end up richer how yet under utilitarian + + align:start position:0% +end up richer how yet under utilitarian + + + align:start position:0% +end up richer how yet under utilitarian +social Ware function we'd call that + + align:start position:0% +social Ware function we'd call that + + + align:start position:0% +social Ware function we'd call that +bad we'd say wait a second John's rich + + align:start position:0% +bad we'd say wait a second John's rich + + + align:start position:0% +bad we'd say wait a second John's rich +or you're poor John should give that + + align:start position:0% +or you're poor John should give that + + + align:start position:0% +or you're poor John should give that +money back to you but why you gave that + + align:start position:0% +money back to you but why you gave that + + + align:start position:0% +money back to you but why you gave that +money to me voluntarily + + align:start position:0% +money to me voluntarily + + + align:start position:0% +money to me voluntarily +so conservative criticism says that + + align:start position:0% +so conservative criticism says that + + + align:start position:0% +so conservative criticism says that +look as long as everyone has equal + + align:start position:0% +look as long as everyone has equal + + + align:start position:0% +look as long as everyone has equal +opportunity we shouldn't care about + + align:start position:0% +opportunity we shouldn't care about + + + align:start position:0% +opportunity we shouldn't care about +outcomes that what matters is + + align:start position:0% +outcomes that what matters is + + + align:start position:0% +outcomes that what matters is +opportunities not outcomes as long as + + align:start position:0% +opportunities not outcomes as long as + + + align:start position:0% +opportunities not outcomes as long as +has equal opportunities then let people + + align:start position:0% +has equal opportunities then let people + + + align:start position:0% +has equal opportunities then let people +spend their money as they want and let + + align:start position:0% +spend their money as they want and let + + + align:start position:0% +spend their money as they want and let +people end up and whatever income + + align:start position:0% +people end up and whatever income + + + align:start position:0% +people end up and whatever income +distribution results if Michael Jordan + + align:start position:0% +distribution results if Michael Jordan + + + align:start position:0% +distribution results if Michael Jordan +ends up rich he's the best at basketball + + align:start position:0% +ends up rich he's the best at basketball + + + align:start position:0% +ends up rich he's the best at basketball +so be it as long as everyone has equal + + align:start position:0% +so be it as long as everyone has equal + + + align:start position:0% +so be it as long as everyone has equal +opportunities this is a theory which + + align:start position:0% +opportunities this is a theory which + + + align:start position:0% +opportunities this is a theory which +says worry about + + align:start position:0% + + + + align:start position:0% + +opportunities not + + align:start position:0% +opportunities not + + + align:start position:0% +opportunities not +outcomes + + align:start position:0% +outcomes + + + align:start position:0% +outcomes +now this + + align:start position:0% +now this + + + align:start position:0% +now this +approach has two fundamental flaws it's + + align:start position:0% +approach has two fundamental flaws it's + + + align:start position:0% +approach has two fundamental flaws it's +pretty compelling the story I told is + + align:start position:0% +pretty compelling the story I told is + + + align:start position:0% +pretty compelling the story I told is +pretty compelling except for two + + align:start position:0% +pretty compelling except for two + + + align:start position:0% +pretty compelling except for two +fundamental + + align:start position:0% +fundamental + + + align:start position:0% +fundamental +problems okay the first problem with + + align:start position:0% +problems okay the first problem with + + + align:start position:0% +problems okay the first problem with +this + + align:start position:0% +this + + + align:start position:0% +this +approach is what does opportunities + + align:start position:0% +approach is what does opportunities + + + align:start position:0% +approach is what does opportunities +mean by definition my kids have better + + align:start position:0% +mean by definition my kids have better + + + align:start position:0% +mean by definition my kids have better +opportunities than the kids born to a + + align:start position:0% +opportunities than the kids born to a + + + align:start position:0% +opportunities than the kids born to a +poor single mother living in a poor part + + align:start position:0% +poor single mother living in a poor part + + + align:start position:0% +poor single mother living in a poor part +of + + align:start position:0% +of + + + align:start position:0% +of +Boston they have more resources there + + align:start position:0% +Boston they have more resources there + + + align:start position:0% +Boston they have more resources there +are better schools things like that so + + align:start position:0% +are better schools things like that so + + + align:start position:0% +are better schools things like that so +in subsense equalizing opportunities is + + align:start position:0% +in subsense equalizing opportunities is + + + align:start position:0% +in subsense equalizing opportunities is +actually by itself pretty radical that + + align:start position:0% +actually by itself pretty radical that + + + align:start position:0% +actually by itself pretty radical that +would involve a large social structural + + align:start position:0% +would involve a large social structural + + + align:start position:0% +would involve a large social structural +change okay so first of all equalizing + + align:start position:0% +change okay so first of all equalizing + + + align:start position:0% +change okay so first of all equalizing +opportunity is not as easy as it sounds + + align:start position:0% +opportunity is not as easy as it sounds + + + align:start position:0% +opportunity is not as easy as it sounds +we don't all start equal it a large + + align:start position:0% +we don't all start equal it a large + + + align:start position:0% +we don't all start equal it a large +social upheaval to get us to that point + + align:start position:0% +social upheaval to get us to that point + + + align:start position:0% +social upheaval to get us to that point +we started equal + + align:start position:0% +we started equal + + + align:start position:0% +we started equal +the second problem with it is it turns + + align:start position:0% +the second problem with it is it turns + + + align:start position:0% +the second problem with it is it turns +out that much of what accounts for + + align:start position:0% +out that much of what accounts for + + + align:start position:0% +out that much of what accounts for +success in life is not skill or hard + + align:start position:0% +success in life is not skill or hard + + + align:start position:0% +success in life is not skill or hard +work but + + align:start position:0% +work but + + + align:start position:0% +work but +luck and in that + + align:start position:0% +luck and in that + + + align:start position:0% +luck and in that +case it's not true that rich people are + + align:start position:0% +case it's not true that rich people are + + + align:start position:0% +case it's not true that rich people are +rich because they deserve it or because + + align:start position:0% +rich because they deserve it or because + + + align:start position:0% +rich because they deserve it or because +they have skills or or they're + + align:start position:0% +they have skills or or they're + + + align:start position:0% +they have skills or or they're +just lucky and why do we necessarily + + align:start position:0% +just lucky and why do we necessarily + + + align:start position:0% +just lucky and why do we necessarily +want to reward luck indeed can't we + + align:start position:0% +want to reward luck indeed can't we + + + align:start position:0% +want to reward luck indeed can't we +think a redistribution is kind of luck + + align:start position:0% +think a redistribution is kind of luck + + + align:start position:0% +think a redistribution is kind of luck +Insurance imagine a world where random + + align:start position:0% +Insurance imagine a world where random + + + align:start position:0% +Insurance imagine a world where random +events going to happen to you you get + + align:start position:0% +events going to happen to you you get + + + align:start position:0% +events going to happen to you you get +hit by a car we talked about why we want + + align:start position:0% +hit by a car we talked about why we want + + + align:start position:0% +hit by a car we talked about why we want +insurance right want Insurance to make + + align:start position:0% +insurance right want Insurance to make + + + align:start position:0% +insurance right want Insurance to make +sure if we get hit by the car don't get + + align:start position:0% +sure if we get hit by the car don't get + + + align:start position:0% +sure if we get hit by the car don't get +hit by the car we're in the same off + + align:start position:0% +hit by the car we're in the same off + + + align:start position:0% +hit by the car we're in the same off +well same thing RS talked about behind + + align:start position:0% +well same thing RS talked about behind + + + align:start position:0% +well same thing RS talked about behind +the veil of ignorance imagine before + + align:start position:0% +the veil of ignorance imagine before + + + align:start position:0% +the veil of ignorance imagine before +you're born you don't know if you're be + + align:start position:0% +you're born you don't know if you're be + + + align:start position:0% +you're born you don't know if you're be +rich or poor you would choose a system + + align:start position:0% +rich or poor you would choose a system + + + align:start position:0% +rich or poor you would choose a system +which would ensure you against being + + align:start position:0% +which would ensure you against being + + + align:start position:0% +which would ensure you against being +poor and that system which would involve + + align:start position:0% +poor and that system which would involve + + + align:start position:0% +poor and that system which would involve +transfers so if much of success is due + + align:start position:0% +transfers so if much of success is due + + + align:start position:0% +transfers so if much of success is due +to luck we're going to want a system + + align:start position:0% +to luck we're going to want a system + + + align:start position:0% +to luck we're going to want a system +that shoots the rich to the poor because + + align:start position:0% +that shoots the rich to the poor because + + + align:start position:0% +that shoots the rich to the poor because +the rich got lucky the poor didn't + + align:start position:0% +the rich got lucky the poor didn't + + + align:start position:0% +the rich got lucky the poor didn't +that's uncertain we want to ensure + + align:start position:0% +that's uncertain we want to ensure + + + align:start position:0% +that's uncertain we want to ensure +against okay fascinating fact if you if + + align:start position:0% +against okay fascinating fact if you if + + + align:start position:0% +against okay fascinating fact if you if +you interview people around the world + + align:start position:0% +you interview people around the world + + + align:start position:0% +you interview people around the world +and ask + + align:start position:0% +and ask + + + align:start position:0% +and ask +them is Success mostly due to hard work + + align:start position:0% +them is Success mostly due to hard work + + + align:start position:0% +them is Success mostly due to hard work +or to luck in the US people say hard + + align:start position:0% +or to luck in the US people say hard + + + align:start position:0% +or to luck in the US people say hard +work in Europe people say luck in Europe + + align:start position:0% +work in Europe people say luck in Europe + + + align:start position:0% +work in Europe people say luck in Europe +they have much higher redistribution + + align:start position:0% +they have much higher redistribution + + + align:start position:0% +they have much higher redistribution +than we do in the US because they have a + + align:start position:0% +than we do in the US because they have a + + + align:start position:0% +than we do in the US because they have a +view that much more success comes from + + align:start position:0% +view that much more success comes from + + + align:start position:0% +view that much more success comes from +luck now the answer is it's both in + + align:start position:0% +luck now the answer is it's both in + + + align:start position:0% +luck now the answer is it's both in +every case but sort of an interesting + + align:start position:0% +every case but sort of an interesting + + + align:start position:0% +every case but sort of an interesting +way to two ways think about the world + + align:start position:0% +way to two ways think about the world + + + align:start position:0% +way to two ways think about the world +and then finally there's a totally + + align:start position:0% +and then finally there's a totally + + + align:start position:0% +and then finally there's a totally +different alternative which has a lot of + + align:start position:0% +different alternative which has a lot of + + + align:start position:0% +different alternative which has a lot of +appeal which is called commodity + + align:start position:0% + + + + align:start position:0% + +egalitarianism commodity egalitarianism + + align:start position:0% +egalitarianism commodity egalitarianism + + + align:start position:0% +egalitarianism commodity egalitarianism +this view has a lot of appeal as well + + align:start position:0% +this view has a lot of appeal as well + + + align:start position:0% +this view has a lot of appeal as well +it's simply says + + align:start position:0% + + + + align:start position:0% + +look let's get rid of this Focus on me + + align:start position:0% +look let's get rid of this Focus on me + + + align:start position:0% +look let's get rid of this Focus on me +versus you that's just + + align:start position:0% +versus you that's just + + + align:start position:0% +versus you that's just +destructive let's take a page from R's + + align:start position:0% +destructive let's take a page from R's + + + align:start position:0% +destructive let's take a page from R's +book and say look let's just make sure + + align:start position:0% +book and say look let's just make sure + + + align:start position:0% +book and say look let's just make sure +that the poor have enough to live and + + align:start position:0% +that the poor have enough to live and + + + align:start position:0% +that the poor have enough to live and +beyond that let it + + align:start position:0% +beyond that let it + + + align:start position:0% +beyond that let it +rip so Kam the view is much like RS who + + align:start position:0% +rip so Kam the view is much like RS who + + + align:start position:0% +rip so Kam the view is much like RS who +want to make sure the poor are a decent + + align:start position:0% +want to make sure the poor are a decent + + + align:start position:0% +want to make sure the poor are a decent +level but we don't care then how much + + align:start position:0% +level but we don't care then how much + + + align:start position:0% +level but we don't care then how much +more the rich have as long as the poor + + align:start position:0% +more the rich have as long as the poor + + + align:start position:0% +more the rich have as long as the poor +have achieved a standard of living where + + align:start position:0% +have achieved a standard of living where + + + align:start position:0% +have achieved a standard of living where +they can survive then let it rip I don't + + align:start position:0% +they can survive then let it rip I don't + + + align:start position:0% +they can survive then let it rip I don't +care how rich Bill Gates is as long as + + align:start position:0% +care how rich Bill Gates is as long as + + + align:start position:0% +care how rich Bill Gates is as long as +each of you can have shelter and food + + align:start position:0% +each of you can have shelter and food + + + align:start position:0% +each of you can have shelter and food +and basic health care and other basic + + align:start position:0% +and basic health care and other basic + + + align:start position:0% +and basic health care and other basic +needs + + align:start position:0% +needs + + + align:start position:0% +needs +met it's kind of a compelling it's kind + + align:start position:0% +met it's kind of a compelling it's kind + + + align:start position:0% +met it's kind of a compelling it's kind +of a compelling um argument right that + + align:start position:0% +of a compelling um argument right that + + + align:start position:0% +of a compelling um argument right that +basically why should I care about guy + + align:start position:0% +basically why should I care about guy + + + align:start position:0% +basically why should I care about guy +who was a billion versus the guy who was + + align:start position:0% +who was a billion versus the guy who was + + + align:start position:0% +who was a billion versus the guy who was +a million all I care was making sure + + align:start position:0% +a million all I care was making sure + + + align:start position:0% +a million all I care was making sure +everybody can lead a decent + + align:start position:0% +everybody can lead a decent + + + align:start position:0% +everybody can lead a decent +life it's in some sense a nice + + align:start position:0% +life it's in some sense a nice + + + align:start position:0% +life it's in some sense a nice +compromise between a lot of these + + align:start position:0% +compromise between a lot of these + + + align:start position:0% +compromise between a lot of these +different views in many ways and it + + align:start position:0% +different views in many ways and it + + + align:start position:0% +different views in many ways and it +speaks to a key issue we'll talk about + + align:start position:0% +speaks to a key issue we'll talk about + + + align:start position:0% +speaks to a key issue we'll talk about +later which is should we really be + + align:start position:0% +later which is should we really be + + + align:start position:0% +later which is should we really be +giving people money or should we be + + align:start position:0% +giving people money or should we be + + + align:start position:0% +giving people money or should we be +giving people the goods like housing and + + align:start position:0% +giving people the goods like housing and + + + align:start position:0% +giving people the goods like housing and +health care that make up a decent + + align:start position:0% +health care that make up a decent + + + align:start position:0% +health care that make up a decent +standard of + + align:start position:0% +standard of + + + align:start position:0% +standard of +living so these are four different views + + align:start position:0% +living so these are four different views + + + align:start position:0% +living so these are four different views +only two of them can been easily + + align:start position:0% +only two of them can been easily + + + align:start position:0% +only two of them can been easily +expressed mathematically these obviously + + align:start position:0% +expressed mathematically these obviously + + + align:start position:0% +expressed mathematically these obviously +can write down models but they're more + + align:start position:0% +can write down models but they're more + + + align:start position:0% +can write down models but they're more +complicated but the bottom line + + align:start position:0% +complicated but the bottom line + + + align:start position:0% +complicated but the bottom line +is with all these + + align:start position:0% +is with all these + + + align:start position:0% +is with all these +views given those views you can figure + + align:start position:0% +views given those views you can figure + + + align:start position:0% +views given those views you can figure +out whether a given policy that + + align:start position:0% +out whether a given policy that + + + align:start position:0% +out whether a given policy that +transfers a person a to person B makes + + align:start position:0% +transfers a person a to person B makes + + + align:start position:0% +transfers a person a to person B makes +sense + + align:start position:0% +sense + + + align:start position:0% +sense +these are different ways of providing a + + align:start position:0% +these are different ways of providing a + + + align:start position:0% +these are different ways of providing a +social welfare + + align:start position:0% +social welfare + + + align:start position:0% +social welfare +framework okay questions about that + + align:start position:0% + + + + align:start position:0% + +yeah sure yeah they're related so here's + + align:start position:0% +yeah sure yeah they're related so here's + + + align:start position:0% +yeah sure yeah they're related so here's +the difference let's say we all decide + + align:start position:0% +the difference let's say we all decide + + + align:start position:0% +the difference let's say we all decide +that everyone needs $50,000 to lead a + + align:start position:0% +that everyone needs $50,000 to lead a + + + align:start position:0% +that everyone needs $50,000 to lead a +decent life in + + align:start position:0% +decent life in + + + align:start position:0% +decent life in +America what commodity Garian say is + + align:start position:0% +America what commodity Garian say is + + + align:start position:0% +America what commodity Garian say is +once everyone has $50,000 + + align:start position:0% +once everyone has $50,000 + + + align:start position:0% +once everyone has $50,000 +I don't care how rich people are above + + align:start position:0% +I don't care how rich people are above + + + align:start position:0% +I don't care how rich people are above +that RS would say I do I don't want I + + align:start position:0% +that RS would say I do I don't want I + + + align:start position:0% +that RS would say I do I don't want I +only if everyone is + + align:start position:0% +only if everyone is + + + align:start position:0% +only if everyone is +$50,000 but one guy's 40 but but but if + + align:start position:0% +$50,000 but one guy's 40 but but but if + + + align:start position:0% +$50,000 but one guy's 40 but but but if +I was $50,000 and someone else is a + + align:start position:0% +I was $50,000 and someone else is a + + + align:start position:0% +I was $50,000 and someone else is a +billion dollars we we' rather make + + align:start position:0% +billion dollars we we' rather make + + + align:start position:0% +billion dollars we we' rather make +everyone else that $50,000 and3 and that + + align:start position:0% +everyone else that $50,000 and3 and that + + + align:start position:0% +everyone else that $50,000 and3 and that +guy back come down to 50,000 and3 we + + align:start position:0% +guy back come down to 50,000 and3 we + + + align:start position:0% +guy back come down to 50,000 and3 we +don't want anybody above the minimum we + + align:start position:0% +don't want anybody above the minimum we + + + align:start position:0% +don't want anybody above the minimum we +want to make sure the minimum is high as + + align:start position:0% +want to make sure the minimum is high as + + + align:start position:0% +want to make sure the minimum is high as +it possibly can be where T says as long + + align:start position:0% +it possibly can be where T says as long + + + align:start position:0% +it possibly can be where T says as long +as the minimum is the decent state of + + align:start position:0% +as the minimum is the decent state of + + + align:start position:0% +as the minimum is the decent state of +living let the rich guy have as much as + + align:start position:0% +living let the rich guy have as much as + + + align:start position:0% +living let the rich guy have as much as +he + + align:start position:0% +he + + + align:start position:0% +he +want RS cares about inequality is a + + align:start position:0% +want RS cares about inequality is a + + + align:start position:0% +want RS cares about inequality is a +concept commodity G terrorism + + align:start position:0% +concept commodity G terrorism + + + align:start position:0% +concept commodity G terrorism +doesn't good question other + + align:start position:0% +doesn't good question other + + + align:start position:0% +doesn't good question other +questions okay so armed with these views + + align:start position:0% +questions okay so armed with these views + + + align:start position:0% +questions okay so armed with these views +let's talk about the facts what do we + + align:start position:0% +let's talk about the facts what do we + + + align:start position:0% +let's talk about the facts what do we +know about + + align:start position:0% +know about + + + align:start position:0% +know about +inequality and here I'm just going to + + align:start position:0% +inequality and here I'm just going to + + + align:start position:0% +inequality and here I'm just going to +run through some facts from my textbook + + align:start position:0% +run through some facts from my textbook + + + align:start position:0% +run through some facts from my textbook +that I used from + + align:start position:0% +that I used from + + + align:start position:0% +that I used from +1441 so let's start with figure + + align:start position:0% +1441 so let's start with figure + + + align:start position:0% +1441 so let's start with figure +23-2 this shows relative income + + align:start position:0% +23-2 this shows relative income + + + align:start position:0% +23-2 this shows relative income +inequality in the United States how do + + align:start position:0% +inequality in the United States how do + + + align:start position:0% +inequality in the United States how do +we do that we divide the population to + + align:start position:0% +we do that we divide the population to + + + align:start position:0% +we do that we divide the population to +quintiles that is fifths of the people + + align:start position:0% +quintiles that is fifths of the people + + + align:start position:0% +quintiles that is fifths of the people +so each of these rows is 20% of the + + align:start position:0% +so each of these rows is 20% of the + + + align:start position:0% +so each of these rows is 20% of the +people each number shows the percent of + + align:start position:0% +people each number shows the percent of + + + align:start position:0% +people each number shows the percent of +income earned by that share of people in + + align:start position:0% +income earned by that share of people in + + + align:start position:0% +income earned by that share of people in +other words in a perfectly equal Society + + align:start position:0% +other words in a perfectly equal Society + + + align:start position:0% +other words in a perfectly equal Society +every number in this table would be 20 + + align:start position:0% +every number in this table would be 20 + + + align:start position:0% +every number in this table would be 20 +in a perfectly equal Society every fifth + + align:start position:0% +in a perfectly equal Society every fifth + + + align:start position:0% +in a perfectly equal Society every fifth +of people would get a fifth of the money + + align:start position:0% +of people would get a fifth of the money + + + align:start position:0% +of people would get a fifth of the money +but in fact that's never true anywhere + + align:start position:0% +but in fact that's never true anywhere + + + align:start position:0% +but in fact that's never true anywhere +you see always the higher + + align:start position:0% +you see always the higher + + + align:start position:0% +you see always the higher +quintiles control a larger share of + + align:start position:0% +quintiles control a larger share of + + + align:start position:0% +quintiles control a larger share of +income that's always true what's more + + align:start position:0% +income that's always true what's more + + + align:start position:0% +income that's always true what's more +notable is how it's changed over time + + align:start position:0% +notable is how it's changed over time + + + align:start position:0% +notable is how it's changed over time +from 1967 to 1980 it stayed relatively + + align:start position:0% +from 1967 to 1980 it stayed relatively + + + align:start position:0% +from 1967 to 1980 it stayed relatively +flat but look from 1980 to + + align:start position:0% +flat but look from 1980 to + + + align:start position:0% +flat but look from 1980 to +2019 the share held by the poorest has + + align:start position:0% +2019 the share held by the poorest has + + + align:start position:0% +2019 the share held by the poorest has +fallen by about + + align:start position:0% +fallen by about + + + align:start position:0% +fallen by about +25% the poorest 20% of people used to + + align:start position:0% +25% the poorest 20% of people used to + + + align:start position:0% +25% the poorest 20% of people used to +earn 4.2% of the income now they get + + align:start position:0% +earn 4.2% of the income now they get + + + align:start position:0% +earn 4.2% of the income now they get +3.1% of the income the richest 20% of + + align:start position:0% +3.1% of the income the richest 20% of + + + align:start position:0% +3.1% of the income the richest 20% of +people in 1980 had 44% of the income now + + align:start position:0% +people in 1980 had 44% of the income now + + + align:start position:0% +people in 1980 had 44% of the income now +they have 52% of the + + align:start position:0% +they have 52% of the + + + align:start position:0% +they have 52% of the +income Society has gotten much more + + align:start position:0% +income Society has gotten much more + + + align:start position:0% +income Society has gotten much more +unequal this has been driven not just by + + align:start position:0% +unequal this has been driven not just by + + + align:start position:0% +unequal this has been driven not just by +the richest 20% to be clear the richest + + align:start position:0% +the richest 20% to be clear the richest + + + align:start position:0% +the richest 20% to be clear the richest +just to fix ideas here the richest 20% + + align:start position:0% +just to fix ideas here the richest 20% + + + align:start position:0% +just to fix ideas here the richest 20% +of people would be people with incomes + + align:start position:0% +of people would be people with incomes + + + align:start position:0% +of people would be people with incomes +above say nationally PE with incomes + + align:start position:0% +above say nationally PE with incomes + + + align:start position:0% +above say nationally PE with incomes +above say + + align:start position:0% +above say + + + align:start position:0% +above say +$85,000 so it's not Mega Rich okay or + + align:start position:0% +$85,000 so it's not Mega Rich okay or + + + align:start position:0% +$85,000 so it's not Mega Rich okay or +maybe $100,000 not Mega Rich it's well + + align:start position:0% +maybe $100,000 not Mega Rich it's well + + + align:start position:0% +maybe $100,000 not Mega Rich it's well +off but not Mega rich but this trend has + + align:start position:0% +off but not Mega rich but this trend has + + + align:start position:0% +off but not Mega rich but this trend has +been driven by the very + + align:start position:0% +been driven by the very + + + align:start position:0% +been driven by the very +wealthy figure 233 shows the share of + + align:start position:0% +wealthy figure 233 shows the share of + + + align:start position:0% +wealthy figure 233 shows the share of +income going to the top 1% of income PE + + align:start position:0% +income going to the top 1% of income PE + + + align:start position:0% +income going to the top 1% of income PE +holders this people income above about + + align:start position:0% +holders this people income above about + + + align:start position:0% +holders this people income above about +$500,000 these are the + + align:start position:0% +$500,000 these are the + + + align:start position:0% +$500,000 these are the +rich + + align:start position:0% +rich + + + align:start position:0% +rich +okay at the turn of the C 20 Century + + align:start position:0% +okay at the turn of the C 20 Century + + + align:start position:0% +okay at the turn of the C 20 Century +1913 and peing right before the Great + + align:start position:0% +1913 and peing right before the Great + + + align:start position:0% +1913 and peing right before the Great +Depression the rich held about 25% of + + align:start position:0% +Depression the rich held about 25% of + + + align:start position:0% +Depression the rich held about 25% of +all in income that is 1% of people got + + align:start position:0% +all in income that is 1% of people got + + + align:start position:0% +all in income that is 1% of people got +25% of the income that fell then fell + + align:start position:0% +25% of the income that fell then fell + + + align:start position:0% +25% of the income that fell then fell +precipitously till in the early 1970s 1% + + align:start position:0% +precipitously till in the early 1970s 1% + + + align:start position:0% +precipitously till in the early 1970s 1% +of people only about 10% of income and + + align:start position:0% +of people only about 10% of income and + + + align:start position:0% +of people only about 10% of income and +it's risen dramatically since so we're + + align:start position:0% +it's risen dramatically since so we're + + + align:start position:0% +it's risen dramatically since so we're +back at the level actually above where + + align:start position:0% +back at the level actually above where + + + align:start position:0% +back at the level actually above where +we were at the peak of the 20th century + + align:start position:0% +we were at the peak of the 20th century + + + align:start position:0% +we were at the peak of the 20th century +with one with the top 1% earning more + + align:start position:0% +with one with the top 1% earning more + + + align:start position:0% +with one with the top 1% earning more +than a quarter of all the resources in + + align:start position:0% +than a quarter of all the resources in + + + align:start position:0% +than a quarter of all the resources in +society so it's a very unequal + + align:start position:0% +society so it's a very unequal + + + align:start position:0% +society so it's a very unequal +Society now you might say well how do I + + align:start position:0% +Society now you might say well how do I + + + align:start position:0% +Society now you might say well how do I +know it's an equal what's what's the + + align:start position:0% +know it's an equal what's what's the + + + align:start position:0% +know it's an equal what's what's the +natural state what I want to do is + + align:start position:0% +natural state what I want to do is + + + align:start position:0% +natural state what I want to do is +compare countries figure 234 Compares + + align:start position:0% +compare countries figure 234 Compares + + + align:start position:0% +compare countries figure 234 Compares +countries this is just a small + + align:start position:0% +countries this is just a small + + + align:start position:0% +countries this is just a small +comparison of some countries that are in + + align:start position:0% +comparison of some countries that are in + + + align:start position:0% +comparison of some countries that are in +the um o just a subset alphabetically of + + align:start position:0% +the um o just a subset alphabetically of + + + align:start position:0% +the um o just a subset alphabetically of +countries that are what we call + + align:start position:0% +countries that are what we call + + + align:start position:0% +countries that are what we call +developed countries from countries that + + align:start position:0% +developed countries from countries that + + + align:start position:0% +developed countries from countries that +we consider our peers like the UK or + + align:start position:0% +we consider our peers like the UK or + + + align:start position:0% +we consider our peers like the UK or +Sweden the countries that are poor like + + align:start position:0% +Sweden the countries that are poor like + + + align:start position:0% +Sweden the countries that are poor like +Czechoslovakia or turkey what you show + + align:start position:0% +Czechoslovakia or turkey what you show + + + align:start position:0% +Czechoslovakia or turkey what you show +here is the share of income held by the + + align:start position:0% +here is the share of income held by the + + + align:start position:0% +here is the share of income held by the +bottom + + align:start position:0% +bottom + + + align:start position:0% +bottom +10% the bottom 20% and the bottom 40% as + + align:start position:0% +10% the bottom 20% and the bottom 40% as + + + align:start position:0% +10% the bottom 20% and the bottom 40% as +well as the top 40% the top 20% the top + + align:start position:0% +well as the top 40% the top 20% the top + + + align:start position:0% +well as the top 40% the top 20% the top +10% just compare the bottom two rows the + + align:start position:0% +10% just compare the bottom two rows the + + + align:start position:0% +10% just compare the bottom two rows the +bottom row is the average for all + + align:start position:0% +bottom row is the average for all + + + align:start position:0% +bottom row is the average for all +developed countries so on average on + + align:start position:0% +developed countries so on average on + + + align:start position:0% +developed countries so on average on +average across all developed countries + + align:start position:0% +average across all developed countries + + + align:start position:0% +average across all developed countries +the bottom 10% of people have 3% of the + + align:start position:0% +the bottom 10% of people have 3% of the + + + align:start position:0% +the bottom 10% of people have 3% of the +income and the top 10% of people have + + align:start position:0% +income and the top 10% of people have + + + align:start position:0% +income and the top 10% of people have +25% of the income in the US the bottom + + align:start position:0% +25% of the income in the US the bottom + + + align:start position:0% +25% of the income in the US the bottom +10 perent of only 1.6% of the the income + + align:start position:0% +10 perent of only 1.6% of the the income + + + align:start position:0% +10 perent of only 1.6% of the the income +and the top 10% have almost 30% of the + + align:start position:0% +and the top 10% have almost 30% of the + + + align:start position:0% +and the top 10% have almost 30% of the +income so the US is unequal it's much + + align:start position:0% +income so the US is unequal it's much + + + align:start position:0% +income so the US is unequal it's much +more unequal indeed we are the most + + align:start position:0% +more unequal indeed we are the most + + + align:start position:0% +more unequal indeed we are the most +unequal what's considered developed + + align:start position:0% +unequal what's considered developed + + + align:start position:0% +unequal what's considered developed +country except for + + align:start position:0% +country except for + + + align:start position:0% +country except for +Mexico we're unequal that any other + + align:start position:0% +Mexico we're unequal that any other + + + align:start position:0% +Mexico we're unequal that any other +country consider a developed country we + + align:start position:0% +country consider a developed country we + + + align:start position:0% +country consider a developed country we +the most unequal except for Mexico and + + align:start position:0% +the most unequal except for Mexico and + + + align:start position:0% +the most unequal except for Mexico and +maybe turkey there's some debate + + align:start position:0% +maybe turkey there's some debate + + + align:start position:0% +maybe turkey there's some debate +there okay so we're very + + align:start position:0% +there okay so we're very + + + align:start position:0% +there okay so we're very +unequal + + align:start position:0% +unequal + + + align:start position:0% +unequal +now many people particularly people in + + align:start position:0% +now many people particularly people in + + + align:start position:0% +now many people particularly people in +these camps three and four would say + + align:start position:0% +these camps three and four would say + + + align:start position:0% +these camps three and four would say +well look that's all well and good but + + align:start position:0% +well look that's all well and good but + + + align:start position:0% +well look that's all well and good but +why you so worried about inequality sure + + align:start position:0% +why you so worried about inequality sure + + + align:start position:0% +why you so worried about inequality sure +we got some rich + + align:start position:0% +we got some rich + + + align:start position:0% +we got some rich +guys but we don't care about that we + + align:start position:0% +guys but we don't care about that we + + + align:start position:0% +guys but we don't care about that we +just care that poor people have enough + + align:start position:0% +just care that poor people have enough + + + align:start position:0% +just care that poor people have enough +to live that's what matters we want to + + align:start position:0% +to live that's what matters we want to + + + align:start position:0% +to live that's what matters we want to +focus on what is the standard of living + + align:start position:0% +focus on what is the standard of living + + + align:start position:0% +focus on what is the standard of living +of the + + align:start position:0% +of the + + + align:start position:0% +of the +poor well in other words they want to + + align:start position:0% +poor well in other words they want to + + + align:start position:0% +poor well in other words they want to +shift their focus + + align:start position:0% +shift their focus + + + align:start position:0% +shift their focus +from + + align:start position:0% +from + + + align:start position:0% +from +relative inequality + + align:start position:0% + + + + align:start position:0% + +versus + + align:start position:0% +versus + + + align:start position:0% +versus +absolute + + align:start position:0% + + + + align:start position:0% + +deprivation that is how what are people + + align:start position:0% +deprivation that is how what are people + + + align:start position:0% +deprivation that is how what are people +actually living on well to do that + + align:start position:0% +actually living on well to do that + + + align:start position:0% +actually living on well to do that +relative the problem with that is + + align:start position:0% +relative the problem with that is + + + align:start position:0% +relative the problem with that is +relative income inequality is easy to + + align:start position:0% +relative income inequality is easy to + + + align:start position:0% +relative income inequality is easy to +measure just look at what group has Rel + + align:start position:0% +measure just look at what group has Rel + + + align:start position:0% +measure just look at what group has Rel +to another it's unit + + align:start position:0% +to another it's unit + + + align:start position:0% +to another it's unit +free once you want to measure absolute + + align:start position:0% +free once you want to measure absolute + + + align:start position:0% +free once you want to measure absolute +deprivation you have to make a stand on + + align:start position:0% +deprivation you have to make a stand on + + + align:start position:0% +deprivation you have to make a stand on +what it means to be + + align:start position:0% +what it means to be + + + align:start position:0% +what it means to be +deprived the the US has taken such a + + align:start position:0% +deprived the the US has taken such a + + + align:start position:0% +deprived the the US has taken such a +stand and we've created something called + + align:start position:0% +stand and we've created something called + + + align:start position:0% +stand and we've created something called +the poverty + + align:start position:0% + + + + align:start position:0% + +line the poverty line is the US + + align:start position:0% +line the poverty line is the US + + + align:start position:0% +line the poverty line is the US +measure of what you need to lead a + + align:start position:0% +measure of what you need to lead a + + + align:start position:0% +measure of what you need to lead a +minimally acceptable life in the + + align:start position:0% +minimally acceptable life in the + + + align:start position:0% +minimally acceptable life in the +US okay below which what does it mean to + + align:start position:0% +US okay below which what does it mean to + + + align:start position:0% +US okay below which what does it mean to +be in poverty now this is a pretty + + align:start position:0% +be in poverty now this is a pretty + + + align:start position:0% +be in poverty now this is a pretty +foundational + + align:start position:0% +foundational + + + align:start position:0% +foundational +concept yet its Origins are very modest + + align:start position:0% +concept yet its Origins are very modest + + + align:start position:0% +concept yet its Origins are very modest +for those of you who think that working + + align:start position:0% +for those of you who think that working + + + align:start position:0% +for those of you who think that working +the government doesn't involve pH being + + align:start position:0% +the government doesn't involve pH being + + + align:start position:0% +the government doesn't involve pH being +government bureaucrat doesn't that much + + align:start position:0% +government bureaucrat doesn't that much + + + align:start position:0% +government bureaucrat doesn't that much +power in the mid 1960s a mid-level + + align:start position:0% +power in the mid 1960s a mid-level + + + align:start position:0% +power in the mid 1960s a mid-level +government bureaucrat made this number + + align:start position:0% +government bureaucrat made this number + + + align:start position:0% +government bureaucrat made this number +up she said well look her name was Molly + + align:start position:0% +up she said well look her name was Molly + + + align:start position:0% +up she said well look her name was Molly +oransky she said look poor people spent + + align:start position:0% +oransky she said look poor people spent + + + align:start position:0% +oransky she said look poor people spent +about a third of their budget on food + + align:start position:0% +about a third of their budget on food + + + align:start position:0% +about a third of their budget on food +let me just price out what a n + + align:start position:0% +let me just price out what a n + + + align:start position:0% +let me just price out what a n +nutritionally adequate diet costs + + align:start position:0% +nutritionally adequate diet costs + + + align:start position:0% +nutritionally adequate diet costs +multiply by three and we'll call that + + align:start position:0% +multiply by three and we'll call that + + + align:start position:0% +multiply by three and we'll call that +the poverty line that exercise updated + + align:start position:0% +the poverty line that exercise updated + + + align:start position:0% +the poverty line that exercise updated +by inflation is literally the way today + + align:start position:0% +by inflation is literally the way today + + + align:start position:0% +by inflation is literally the way today +we transfer trillions of dollars in the + + align:start position:0% +we transfer trillions of dollars in the + + + align:start position:0% +we transfer trillions of dollars in the +United + + align:start position:0% +United + + + align:start position:0% +United +States okay so that has remained our + + align:start position:0% +States okay so that has remained our + + + align:start position:0% +States okay so that has remained our +standard for what is + + align:start position:0% +standard for what is + + + align:start position:0% +standard for what is +poor the poverty line itself is shown in + + align:start position:0% +poor the poverty line itself is shown in + + + align:start position:0% +poor the poverty line itself is shown in +figure + + align:start position:0% +figure + + + align:start position:0% +figure +23-5 so the poverty line for a family of + + align:start position:0% +23-5 so the poverty line for a family of + + + align:start position:0% +23-5 so the poverty line for a family of +one is considered to be about + + align:start position:0% + + + + align:start position:0% + +$133,000 it then doesn't double per + + align:start position:0% +$133,000 it then doesn't double per + + + align:start position:0% +$133,000 it then doesn't double per +person because we view that living + + align:start position:0% +person because we view that living + + + align:start position:0% +person because we view that living +together has economies of scale we don't + + align:start position:0% +together has economies of scale we don't + + + align:start position:0% +together has economies of scale we don't +think you need twice as much money for + + align:start position:0% +think you need twice as much money for + + + align:start position:0% +think you need twice as much money for +two people to live together + + align:start position:0% +two people to live together + + + align:start position:0% +two people to live together +as you do for one person to live + + align:start position:0% +as you do for one person to live + + + align:start position:0% +as you do for one person to live +together because for instance a + + align:start position:0% +together because for instance a + + + align:start position:0% +together because for instance a +two-bedroom apartment is typically not + + align:start position:0% +two-bedroom apartment is typically not + + + align:start position:0% +two-bedroom apartment is typically not +twice a one-bedroom apartment certainly + + align:start position:0% +twice a one-bedroom apartment certainly + + + align:start position:0% +twice a one-bedroom apartment certainly +a so basically there's economies of + + align:start position:0% +a so basically there's economies of + + + align:start position:0% +a so basically there's economies of +scale so it doesn't double but it goes + + align:start position:0% +scale so it doesn't double but it goes + + + align:start position:0% +scale so it doesn't double but it goes +up thereafter So a family of four we + + align:start position:0% +up thereafter So a family of four we + + + align:start position:0% +up thereafter So a family of four we +think as a poverty line of about twice + + align:start position:0% +think as a poverty line of about twice + + + align:start position:0% +think as a poverty line of about twice +the poverty line for an + + align:start position:0% +the poverty line for an + + + align:start position:0% +the poverty line for an +individual now is that a fair number is + + align:start position:0% +individual now is that a fair number is + + + align:start position:0% +individual now is that a fair number is +that correct well that's a debate for + + align:start position:0% +that correct well that's a debate for + + + align:start position:0% +that correct well that's a debate for +another day we can come to 1441 we spent + + align:start position:0% +another day we can come to 1441 we spent + + + align:start position:0% +another day we can come to 1441 we spent +a lot of time talking about it it's a + + align:start position:0% +a lot of time talking about it it's a + + + align:start position:0% +a lot of time talking about it it's a +very controversial number for many + + align:start position:0% +very controversial number for many + + + align:start position:0% +very controversial number for many +reasons let's take that as given for now + + align:start position:0% +reasons let's take that as given for now + + + align:start position:0% +reasons let's take that as given for now +what does it implies happen over time + + align:start position:0% +what does it implies happen over time + + + align:start position:0% +what does it implies happen over time +well look at figure + + align:start position:0% +well look at figure + + + align:start position:0% +well look at figure +23-6 which shows poverty rates over time + + align:start position:0% +23-6 which shows poverty rates over time + + + align:start position:0% +23-6 which shows poverty rates over time +what you see if you look at the blue + + align:start position:0% +what you see if you look at the blue + + + align:start position:0% +what you see if you look at the blue +line that's all people you see for all + + align:start position:0% +line that's all people you see for all + + + align:start position:0% +line that's all people you see for all +people poverty rates fell dramatically + + align:start position:0% +people poverty rates fell dramatically + + + align:start position:0% +people poverty rates fell dramatically +until about + + align:start position:0% +until about + + + align:start position:0% +until about +1979 and then have been pretty flat + + align:start position:0% +1979 and then have been pretty flat + + + align:start position:0% +1979 and then have been pretty flat +since that's been that's a combination + + align:start position:0% +since that's been that's a combination + + + align:start position:0% +since that's been that's a combination +of a dramatic fall in poverty for those + + align:start position:0% +of a dramatic fall in poverty for those + + + align:start position:0% +of a dramatic fall in poverty for those +I'm sorry that's not the Blue Line uh + + align:start position:0% +I'm sorry that's not the Blue Line uh + + + align:start position:0% +I'm sorry that's not the Blue Line uh +yeah let's see no the I'm sorry the blue + + align:start position:0% +yeah let's see no the I'm sorry the blue + + + align:start position:0% +yeah let's see no the I'm sorry the blue +line is I'm sorry the red line is all + + align:start position:0% +line is I'm sorry the red line is all + + + align:start position:0% +line is I'm sorry the red line is all +people my bad it fell for dramatically + + align:start position:0% +people my bad it fell for dramatically + + + align:start position:0% +people my bad it fell for dramatically +until about 1970 and then it's been flat + + align:start position:0% +until about 1970 and then it's been flat + + + align:start position:0% +until about 1970 and then it's been flat +since that's a combination of a dramatic + + align:start position:0% +since that's a combination of a dramatic + + + align:start position:0% +since that's a combination of a dramatic +Fallen poverty for the elderly which is + + align:start position:0% +Fallen poverty for the elderly which is + + + align:start position:0% +Fallen poverty for the elderly which is +the blue line and actually poverty kind + + align:start position:0% +the blue line and actually poverty kind + + + align:start position:0% +the blue line and actually poverty kind +of has been risen a bit for the for the + + align:start position:0% +of has been risen a bit for the for the + + + align:start position:0% +of has been risen a bit for the for the +for youth that's under 18 but the bottom + + align:start position:0% +for youth that's under 18 but the bottom + + + align:start position:0% +for youth that's under 18 but the bottom +line is you look at this line for about + + align:start position:0% +line is you look at this line for about + + + align:start position:0% +line is you look at this line for about +1980 onward and it all looks pretty flat + + align:start position:0% +1980 onward and it all looks pretty flat + + + align:start position:0% +1980 onward and it all looks pretty flat +right contrast that + + align:start position:0% +right contrast that + + + align:start position:0% +right contrast that +to I'll go all the way back to table + + align:start position:0% +to I'll go all the way back to table + + + align:start position:0% +to I'll go all the way back to table +232 table 2 32 seem to show that + + align:start position:0% +232 table 2 32 seem to show that + + + align:start position:0% +232 table 2 32 seem to show that +inequality's gotten a ton worse since + + align:start position:0% +inequality's gotten a ton worse since + + + align:start position:0% +inequality's gotten a ton worse since +1980 so how you feel about what's + + align:start position:0% +1980 so how you feel about what's + + + align:start position:0% +1980 so how you feel about what's +happened to American society depends + + align:start position:0% +happened to American society depends + + + align:start position:0% +happened to American society depends +very much on how you feel about fig + + align:start position:0% +very much on how you feel about fig + + + align:start position:0% +very much on how you feel about fig +table 232 figure 232 versus figure + + align:start position:0% +table 232 figure 232 versus figure + + + align:start position:0% +table 232 figure 232 versus figure +236 do we care about what's happened + + align:start position:0% +236 do we care about what's happened + + + align:start position:0% +236 do we care about what's happened +relatively which is the rich Rel to the + + align:start position:0% +relatively which is the rich Rel to the + + + align:start position:0% +relatively which is the rich Rel to the +poor which approach one and two would + + align:start position:0% +poor which approach one and two would + + + align:start position:0% +poor which approach one and two would +say we should care + + align:start position:0% +say we should care + + + align:start position:0% +say we should care +about or do we care which happen + + align:start position:0% +about or do we care which happen + + + align:start position:0% +about or do we care which happen +absolutely which is what the poor have + + align:start position:0% +absolutely which is what the poor have + + + align:start position:0% +absolutely which is what the poor have +which is what approach for we should + + align:start position:0% +which is what approach for we should + + + align:start position:0% +which is what approach for we should +worry + + align:start position:0% +worry + + + align:start position:0% +worry +about and there's no right answer but + + align:start position:0% +about and there's no right answer but + + + align:start position:0% +about and there's no right answer but +how you think about it determines how + + align:start position:0% +how you think about it determines how + + + align:start position:0% +how you think about it determines how +you're going to um end up uh end up + + align:start position:0% +you're going to um end up uh end up + + + align:start position:0% +you're going to um end up uh end up +thinking about the + + align:start position:0% +thinking about the + + + align:start position:0% +thinking about the +problem to my mind I think you want some + + align:start position:0% +problem to my mind I think you want some + + + align:start position:0% +problem to my mind I think you want some +of both but to my mind the simplest and + + align:start position:0% +of both but to my mind the simplest and + + + align:start position:0% +of both but to my mind the simplest and +most striking way to think about this is + + align:start position:0% +most striking way to think about this is + + + align:start position:0% +most striking way to think about this is +the following example which is just + + align:start position:0% +the following example which is just + + + align:start position:0% +the following example which is just +stunning many of you may remember about + + align:start position:0% +stunning many of you may remember about + + + align:start position:0% +stunning many of you may remember about +10 years ago there were the maybe less + + align:start position:0% +10 years ago there were the maybe less + + + align:start position:0% +10 years ago there were the maybe less +there was the Freddy gray riots Freddy + + align:start position:0% +there was the Freddy gray riots Freddy + + + align:start position:0% +there was the Freddy gray riots Freddy +gray was a prisoner arrested in a poor + + align:start position:0% +gray was a prisoner arrested in a poor + + + align:start position:0% +gray was a prisoner arrested in a poor +neighborhood of Baltimore he was killed + + align:start position:0% +neighborhood of Baltimore he was killed + + + align:start position:0% +neighborhood of Baltimore he was killed +in the police car on the way to the + + align:start position:0% +in the police car on the way to the + + + align:start position:0% +in the police car on the way to the +police station it led to uh as part of + + align:start position:0% +police station it led to uh as part of + + + align:start position:0% +police station it led to uh as part of +the black you know one of the founding + + align:start position:0% +the black you know one of the founding + + + align:start position:0% +the black you know one of the founding +events of black lives matter movement + + align:start position:0% +events of black lives matter movement + + + align:start position:0% +events of black lives matter movement +led to a lot of riots and things like + + align:start position:0% +led to a lot of riots and things like + + + align:start position:0% +led to a lot of riots and things like +that in + + align:start position:0% +that in + + + align:start position:0% +that in +Baltimore those riots highlighted how + + align:start position:0% +Baltimore those riots highlighted how + + + align:start position:0% +Baltimore those riots highlighted how +much inequality there is in + + align:start position:0% +much inequality there is in + + + align:start position:0% +much inequality there is in +Baltimore go to figure one of my I think + + align:start position:0% +Baltimore go to figure one of my I think + + + align:start position:0% +Baltimore go to figure one of my I think +one of the most stunning figures I've + + align:start position:0% +one of the most stunning figures I've + + + align:start position:0% +one of the most stunning figures I've +ever seen figure 237 + + align:start position:0% +ever seen figure 237 + + + align:start position:0% +ever seen figure 237 +this figure this is just a graph of + + align:start position:0% +this figure this is just a graph of + + + align:start position:0% +this figure this is just a graph of +Baltimore this shows neighborhoods in + + align:start position:0% +Baltimore this shows neighborhoods in + + + align:start position:0% +Baltimore this shows neighborhoods in +Baltimore and the life expectancy in + + align:start position:0% +Baltimore and the life expectancy in + + + align:start position:0% +Baltimore and the life expectancy in +each neighborhood how long you expect to + + align:start position:0% +each neighborhood how long you expect to + + + align:start position:0% +each neighborhood how long you expect to +live and I'm going to highlight two + + align:start position:0% +live and I'm going to highlight two + + + align:start position:0% +live and I'm going to highlight two +neighborhoods Sandtown + + align:start position:0% +neighborhoods Sandtown + + + align:start position:0% +neighborhoods Sandtown +Winchester which is where Freddy gray + + align:start position:0% +Winchester which is where Freddy gray + + + align:start position:0% +Winchester which is where Freddy gray +was from and Roland Park which is three + + align:start position:0% +was from and Roland Park which is three + + + align:start position:0% +was from and Roland Park which is three +miles + + align:start position:0% +miles + + + align:start position:0% +miles +away where Freddy gray was from the + + align:start position:0% +away where Freddy gray was from the + + + align:start position:0% +away where Freddy gray was from the +average life expectancy unless Roland + + align:start position:0% +average life expectancy unless Roland + + + align:start position:0% +average life expectancy unless Roland +Park Roland Park is a wealthy + + align:start position:0% +Park Roland Park is a wealthy + + + align:start position:0% +Park Roland Park is a wealthy +neighborhood typical sort of wealthy + + align:start position:0% +neighborhood typical sort of wealthy + + + align:start position:0% +neighborhood typical sort of wealthy +suburb the average life there is 84 + + align:start position:0% +suburb the average life there is 84 + + + align:start position:0% +suburb the average life there is 84 +that's above the US average three miles + + align:start position:0% +that's above the US average three miles + + + align:start position:0% +that's above the US average three miles +away where Freddy gray is from the + + align:start position:0% +away where Freddy gray is from the + + + align:start position:0% +away where Freddy gray is from the +average Lifey was + + align:start position:0% +average Lifey was + + + align:start position:0% +average Lifey was +67 that is below the life expectancy of + + align:start position:0% +67 that is below the life expectancy of + + + align:start position:0% +67 that is below the life expectancy of +North + + align:start position:0% +North + + + align:start position:0% +North +Korea three miles and a 17year + + align:start position:0% +Korea three miles and a 17year + + + align:start position:0% +Korea three miles and a 17year +difference and how long you can expect + + align:start position:0% +difference and how long you can expect + + + align:start position:0% +difference and how long you can expect +to + + align:start position:0% +to + + + align:start position:0% +to +live I don't see how anyone can look at + + align:start position:0% +live I don't see how anyone can look at + + + align:start position:0% +live I don't see how anyone can look at +that and not care about inequality + + align:start position:0% +that and not care about inequality + + + align:start position:0% +that and not care about inequality +how can you not care about a world where + + align:start position:0% +how can you not care about a world where + + + align:start position:0% +how can you not care about a world where +people living three miles apart have a + + align:start position:0% +people living three miles apart have a + + + align:start position:0% +people living three miles apart have a +17-year difference and how long they + + align:start position:0% +17-year difference and how long they + + + align:start position:0% +17-year difference and how long they +expect to live what's going on three + + align:start position:0% +expect to live what's going on three + + + align:start position:0% +expect to live what's going on three +miles away the average income in Sant + + align:start position:0% +miles away the average income in Sant + + + align:start position:0% +miles away the average income in Sant +toown is four times the average in the + + align:start position:0% +toown is four times the average in the + + + align:start position:0% +toown is four times the average in the +average in sorry Roland Park is four + + align:start position:0% +average in sorry Roland Park is four + + + align:start position:0% +average in sorry Roland Park is four +times the average income in Sandown in + + align:start position:0% +times the average income in Sandown in + + + align:start position:0% +times the average income in Sandown in +Roland Park 2.5% of kids live in poverty + + align:start position:0% +Roland Park 2.5% of kids live in poverty + + + align:start position:0% +Roland Park 2.5% of kids live in poverty +in Sant toown 55% of kids live in + + align:start position:0% +in Sant toown 55% of kids live in + + + align:start position:0% +in Sant toown 55% of kids live in +poverty okay three + + align:start position:0% +poverty okay three + + + align:start position:0% +poverty okay three +miles and and the odds a kid lives in + + align:start position:0% +miles and and the odds a kid lives in + + + align:start position:0% +miles and and the odds a kid lives in +party is 20 times + + align:start position:0% +party is 20 times + + + align:start position:0% +party is 20 times +different these are the reasons why many + + align:start position:0% +different these are the reasons why many + + + align:start position:0% +different these are the reasons why many +of us feel very strong that we need to + + align:start position:0% +of us feel very strong that we need to + + + align:start position:0% +of us feel very strong that we need to +address inequality as well as simply + + align:start position:0% +address inequality as well as simply + + + align:start position:0% +address inequality as well as simply +absolute + + align:start position:0% +absolute + + + align:start position:0% +absolute +deprivation okay questions about + + align:start position:0% +deprivation okay questions about + + + align:start position:0% +deprivation okay questions about +that now with that in mind let's talk + + align:start position:0% + + + + align:start position:0% + +about what do we do about it so let's + + align:start position:0% +about what do we do about it so let's + + + align:start position:0% +about what do we do about it so let's +say I've got you at least + + align:start position:0% +say I've got you at least + + + align:start position:0% +say I've got you at least +motivated let's say you came in this not + + align:start position:0% +motivated let's say you came in this not + + + align:start position:0% +motivated let's say you came in this not +really thinking about rich versus poor I + + align:start position:0% +really thinking about rich versus poor I + + + align:start position:0% +really thinking about rich versus poor I +hope at least motivated you think it's + + align:start position:0% +hope at least motivated you think it's + + + align:start position:0% +hope at least motivated you think it's +interesting problem and think about + + align:start position:0% +interesting problem and think about + + + align:start position:0% +interesting problem and think about +maybe it's something we might want to do + + align:start position:0% +maybe it's something we might want to do + + + align:start position:0% +maybe it's something we might want to do +something + + align:start position:0% +something + + + align:start position:0% +something +about well to do so we run + + align:start position:0% +about well to do so we run + + + align:start position:0% +about well to do so we run +into an important problem because + + align:start position:0% +into an important problem because + + + align:start position:0% +into an important problem because +remember with the Dismal science right + + align:start position:0% +remember with the Dismal science right + + + align:start position:0% +remember with the Dismal science right +nothing's + + align:start position:0% +nothing's + + + align:start position:0% +nothing's +easy okay the problem is the efficiency + + align:start position:0% + + + + align:start position:0% + +costs of redistribution remember I said + + align:start position:0% +costs of redistribution remember I said + + + align:start position:0% +costs of redistribution remember I said +life isn't typically like our example of + + align:start position:0% +life isn't typically like our example of + + + align:start position:0% +life isn't typically like our example of +perfect competition versus perfectly + + align:start position:0% +perfect competition versus perfectly + + + align:start position:0% +perfect competition versus perfectly +pric monopolist typically in life if we + + align:start position:0% +pric monopolist typically in life if we + + + align:start position:0% +pric monopolist typically in life if we +want to take money from one group we + + align:start position:0% +want to take money from one group we + + + align:start position:0% +want to take money from one group we +give it to another there's a leak in the + + align:start position:0% +give it to another there's a leak in the + + + align:start position:0% +give it to another there's a leak in the +bucket what is that leak in the + + align:start position:0% +bucket what is that leak in the + + + align:start position:0% +bucket what is that leak in the +bucket okay well there's fundamentally + + align:start position:0% +bucket okay well there's fundamentally + + + align:start position:0% +bucket okay well there's fundamentally +two leaks so let's say the way we do + + align:start position:0% +two leaks so let's say the way we do + + + align:start position:0% +two leaks so let's say the way we do +redistribution in reality is we tax the + + align:start position:0% +redistribution in reality is we tax the + + + align:start position:0% +redistribution in reality is we tax the +rich and give money to the + + align:start position:0% +rich and give money to the + + + align:start position:0% +rich and give money to the +poor okay well that leads to S two + + align:start position:0% +poor okay well that leads to S two + + + align:start position:0% +poor okay well that leads to S two +sources of + + align:start position:0% +sources of + + + align:start position:0% +sources of +leakage the first source of leakage is + + align:start position:0% +leakage the first source of leakage is + + + align:start position:0% +leakage the first source of leakage is +when you is the dead weight + + align:start position:0% +when you is the dead weight + + + align:start position:0% +when you is the dead weight +loss of + + align:start position:0% + + + + align:start position:0% + +Taxation when you tax an + + align:start position:0% +Taxation when you tax an + + + align:start position:0% +Taxation when you tax an +activity you create less of it and that + + align:start position:0% +activity you create less of it and that + + + align:start position:0% +activity you create less of it and that +has a dead weight loss because there's + + align:start position:0% +has a dead weight loss because there's + + + align:start position:0% +has a dead weight loss because there's +social optimal trades that no longer get + + align:start position:0% +social optimal trades that no longer get + + + align:start position:0% +social optimal trades that no longer get +made that's the first source of + + align:start position:0% +made that's the first source of + + + align:start position:0% +made that's the first source of +leakage the second source of leeches + + align:start position:0% +leakage the second source of leeches + + + align:start position:0% +leakage the second source of leeches +leakage is the is the dead weight loss + + align:start position:0% +leakage is the is the dead weight loss + + + align:start position:0% +leakage is the is the dead weight loss +of transfers which is a little more + + align:start position:0% +of transfers which is a little more + + + align:start position:0% +of transfers which is a little more +subtle but actually works the same way + + align:start position:0% +subtle but actually works the same way + + + align:start position:0% +subtle but actually works the same way +when you + + align:start position:0% +when you + + + align:start position:0% +when you +subsidize a lack of economic activity + + align:start position:0% +subsidize a lack of economic activity + + + align:start position:0% +subsidize a lack of economic activity +you create more of it that's the moral + + align:start position:0% +you create more of it that's the moral + + + align:start position:0% +you create more of it that's the moral +hazard problem we talked about last + + align:start position:0% +hazard problem we talked about last + + + align:start position:0% +hazard problem we talked about last +time so you tax something activity you + + align:start position:0% +time so you tax something activity you + + + align:start position:0% +time so you tax something activity you +create less of it when you subze a lack + + align:start position:0% +create less of it when you subze a lack + + + align:start position:0% +create less of it when you subze a lack +of activity you create more of it + + align:start position:0% +of activity you create more of it + + + align:start position:0% +of activity you create more of it +transferring from Rich to poor involves + + align:start position:0% +transferring from Rich to poor involves + + + align:start position:0% +transferring from Rich to poor involves +both ends of that so it's double weight + + align:start position:0% +both ends of that so it's double weight + + + align:start position:0% +both ends of that so it's double weight +loss you + + align:start position:0% +loss you + + + align:start position:0% +loss you +create okay so to see that we're going + + align:start position:0% +create okay so to see that we're going + + + align:start position:0% +create okay so to see that we're going +to go through a fairly large example + + align:start position:0% +to go through a fairly large example + + + align:start position:0% +to go through a fairly large example +here we're going to end the lecture with + + align:start position:0% +here we're going to end the lecture with + + + align:start position:0% +here we're going to end the lecture with +sort of a strong example which + + align:start position:0% +sort of a strong example which + + + align:start position:0% +sort of a strong example which +illustrates this point okay in this + + align:start position:0% +illustrates this point okay in this + + + align:start position:0% +illustrates this point okay in this +example we're g to say everyone earns + + align:start position:0% +example we're g to say everyone earns + + + align:start position:0% +example we're g to say everyone earns +$20 an hour so our example the wage for + + align:start position:0% +$20 an hour so our example the wage for + + + align:start position:0% +$20 an hour so our example the wage for +everyone's Society is be $20 an hour so + + align:start position:0% +everyone's Society is be $20 an hour so + + + align:start position:0% +everyone's Society is be $20 an hour so +everyone has the same + + align:start position:0% +everyone has the same + + + align:start position:0% +everyone has the same +underlying marginal product of labor + + align:start position:0% +underlying marginal product of labor + + + align:start position:0% +underlying marginal product of labor +every side he ears $20 an hour marginal + + align:start position:0% +every side he ears $20 an hour marginal + + + align:start position:0% +every side he ears $20 an hour marginal +revenue product of labor + + align:start position:0% +revenue product of labor + + + align:start position:0% +revenue product of labor +but different people earn different + + align:start position:0% +but different people earn different + + + align:start position:0% +but different people earn different +amounts of income and society's + + align:start position:0% +amounts of income and society's + + + align:start position:0% +amounts of income and society's +utilitarian the government utilitarian + + align:start position:0% +utilitarian the government utilitarian + + + align:start position:0% +utilitarian the government utilitarian +so it cares about that different + + align:start position:0% +so it cares about that different + + + align:start position:0% +so it cares about that different +different amounts of income so let's say + + align:start position:0% +different amounts of income so let's say + + + align:start position:0% +different amounts of income so let's say +that the government wants to make sure + + align:start position:0% +that the government wants to make sure + + + align:start position:0% +that the government wants to make sure +that there's a minimum guarantee the + + align:start position:0% +that there's a minimum guarantee the + + + align:start position:0% +that there's a minimum guarantee the +government's a commodity + + align:start position:0% +government's a commodity + + + align:start position:0% +government's a commodity +galarian the government says you know + + align:start position:0% +galarian the government says you know + + + align:start position:0% +galarian the government says you know +what I want to make sure there's a + + align:start position:0% +what I want to make sure there's a + + + align:start position:0% +what I want to make sure there's a +minimum guarantee of + + align:start position:0% +minimum guarantee of + + + align:start position:0% +minimum guarantee of +$5,000 I want to make sure that everyone + + align:start position:0% +$5,000 I want to make sure that everyone + + + align:start position:0% +$5,000 I want to make sure that everyone +in society has at least + + align:start position:0% +in society has at least + + + align:start position:0% +in society has at least +$5,000 because I feel like you can't + + align:start position:0% +$5,000 because I feel like you can't + + + align:start position:0% +$5,000 because I feel like you can't +survive with less than + + align:start position:0% +survive with less than + + + align:start position:0% +survive with less than +$5,000 but I have to pay for that so the + + align:start position:0% +$5,000 but I have to pay for that so the + + + align:start position:0% +$5,000 but I have to pay for that so the +way I'm going to pay for that I'm have + + align:start position:0% +way I'm going to pay for that I'm have + + + align:start position:0% +way I'm going to pay for that I'm have +I'm gonna have a + + align:start position:0% +I'm gonna have a + + + align:start position:0% +I'm gonna have a +tax and the tax is going to + + align:start position:0% +tax and the tax is going to + + + align:start position:0% +tax and the tax is going to +be that anyone with + + align:start position:0% +be that anyone with + + + align:start position:0% +be that anyone with +income + + align:start position:0% +income + + + align:start position:0% +income +um oh I'm sorry let me go back so let me + + align:start position:0% +um oh I'm sorry let me go back so let me + + + align:start position:0% +um oh I'm sorry let me go back so let me +go back let me finish this first there's + + align:start position:0% +go back let me finish this first there's + + + align:start position:0% +go back let me finish this first there's +a guarantee of $5,000 but here's the + + align:start position:0% +a guarantee of $5,000 but here's the + + + align:start position:0% +a guarantee of $5,000 but here's the +thing I'm not going to give everyone + + align:start position:0% +thing I'm not going to give everyone + + + align:start position:0% +thing I'm not going to give everyone +$5,000 I want make sure everybody has + + align:start position:0% +$5,000 I want make sure everybody has + + + align:start position:0% +$5,000 I want make sure everybody has +$5,000 but if you have some money + + align:start position:0% +$5,000 but if you have some money + + + align:start position:0% +$5,000 but if you have some money +already I don't want I don't want to + + align:start position:0% +already I don't want I don't want to + + + align:start position:0% +already I don't want I don't want to +guarantee you have $7,000 I'm make sure + + align:start position:0% +guarantee you have $7,000 I'm make sure + + + align:start position:0% +guarantee you have $7,000 I'm make sure +have $5,000 so what I'm going to do is + + align:start position:0% +have $5,000 so what I'm going to do is + + + align:start position:0% +have $5,000 so what I'm going to do is +I'm set up a transfer program that's + + align:start position:0% +I'm set up a transfer program that's + + + align:start position:0% +I'm set up a transfer program that's +what we call a negative income tax the + + align:start position:0% +what we call a negative income tax the + + + align:start position:0% +what we call a negative income tax the +way it works is if you have zero I give + + align:start position:0% +way it works is if you have zero I give + + + align:start position:0% +way it works is if you have zero I give +you 5,000 you have 100 I give you + + align:start position:0% +you 5,000 you have 100 I give you + + + align:start position:0% +you 5,000 you have 100 I give you +4,900 if you a th000 I give you 4,000 + + align:start position:0% +4,900 if you a th000 I give you 4,000 + + + align:start position:0% +4,900 if you a th000 I give you 4,000 +that is I top up your income to get you + + align:start position:0% +that is I top up your income to get you + + + align:start position:0% +that is I top up your income to get you +to 5,000 in particular I give you a + + align:start position:0% +to 5,000 in particular I give you a + + + align:start position:0% +to 5,000 in particular I give you a +transfer I give you a transfer which is + + align:start position:0% +transfer I give you a transfer which is + + + align:start position:0% +transfer I give you a transfer which is +equal to + + align:start position:0% +equal to + + + align:start position:0% +equal to +the + + align:start position:0% +the + + + align:start position:0% +the +max of 0 comma + + align:start position:0% +max of 0 comma + + + align:start position:0% +max of 0 comma +5000 minus y That's the transfer I give + + align:start position:0% +5000 minus y That's the transfer I give + + + align:start position:0% +5000 minus y That's the transfer I give +you I give you if your income's above + + align:start position:0% +you I give you if your income's above + + + align:start position:0% +you I give you if your income's above +5,000 I give you nothing if your + + align:start position:0% +5,000 I give you nothing if your + + + align:start position:0% +5,000 I give you nothing if your +income's below 5,000 give you enough to + + align:start position:0% +income's below 5,000 give you enough to + + + align:start position:0% +income's below 5,000 give you enough to +get up to 5,000 that's how I Implement + + align:start position:0% +get up to 5,000 that's how I Implement + + + align:start position:0% +get up to 5,000 that's how I Implement +my commodi egalitarianism solution I get + + align:start position:0% +my commodi egalitarianism solution I get + + + align:start position:0% +my commodi egalitarianism solution I get +everyone up to 5,000 people clear on + + align:start position:0% +everyone up to 5,000 people clear on + + + align:start position:0% +everyone up to 5,000 people clear on +that I get them up to + + align:start position:0% +that I get them up to + + + align:start position:0% +that I get them up to +5,000 okay and to assment of a + + align:start position:0% +5,000 okay and to assment of a + + + align:start position:0% +5,000 okay and to assment of a +tax the tax is going to be only on the + + align:start position:0% +tax the tax is going to be only on the + + + align:start position:0% +tax the tax is going to be only on the +rich so what I'm going to do is I'm + + align:start position:0% +rich so what I'm going to do is I'm + + + align:start position:0% +rich so what I'm going to do is I'm +going to say anyone whose earnings is + + align:start position:0% +going to say anyone whose earnings is + + + align:start position:0% +going to say anyone whose earnings is +above + + align:start position:0% +above + + + align:start position:0% +above +$20,000 is going to be is going to pay a + + align:start position:0% +$20,000 is going to be is going to pay a + + + align:start position:0% +$20,000 is going to be is going to pay a +50% tax + + align:start position:0% +50% tax + + + align:start position:0% +50% tax +rate + + align:start position:0% +rate + + + align:start position:0% +rate +above 20K just on your earnings above + + align:start position:0% +above 20K just on your earnings above + + + align:start position:0% +above 20K just on your earnings above +20K so all earnings below 20K I don't + + align:start position:0% +20K so all earnings below 20K I don't + + + align:start position:0% +20K so all earnings below 20K I don't +touch but on any earnings above 20K I'm + + align:start position:0% +touch but on any earnings above 20K I'm + + + align:start position:0% +touch but on any earnings above 20K I'm +going to take back half of it to finance + + align:start position:0% +going to take back half of it to finance + + + align:start position:0% +going to take back half of it to finance +this + + align:start position:0% + + + + align:start position:0% + +program okay that's the way the program + + align:start position:0% +program okay that's the way the program + + + align:start position:0% +program okay that's the way the program +is going to + + align:start position:0% +is going to + + + align:start position:0% +is going to +work well let's see how that affects + + align:start position:0% +work well let's see how that affects + + + align:start position:0% +work well let's see how that affects +people's budget + + align:start position:0% +people's budget + + + align:start position:0% +people's budget +constraint let's go to figure + + align:start position:0% +constraint let's go to figure + + + align:start position:0% +constraint let's go to figure +23-8 this is a standard Leisure + + align:start position:0% +23-8 this is a standard Leisure + + + align:start position:0% +23-8 this is a standard Leisure +consumption + + align:start position:0% +consumption + + + align:start position:0% +consumption +tradeoff okay we people remember I said + + align:start position:0% +tradeoff okay we people remember I said + + + align:start position:0% +tradeoff okay we people remember I said +earn 20 bucks an hour so without the + + align:start position:0% +earn 20 bucks an hour so without the + + + align:start position:0% +earn 20 bucks an hour so without the +government the budget constraint is the + + align:start position:0% +government the budget constraint is the + + + align:start position:0% +government the budget constraint is the +black line they can work up to 2,000 + + align:start position:0% +black line they can work up to 2,000 + + + align:start position:0% +black line they can work up to 2,000 +hours a + + align:start position:0% +hours a + + + align:start position:0% +hours a +year and have no no + + align:start position:0% +year and have no no + + + align:start position:0% +year and have no no +consumption I'm sorry they can take + + align:start position:0% +consumption I'm sorry they can take + + + align:start position:0% +consumption I'm sorry they can take +2,000 hours a year Leisure my bad + + align:start position:0% +2,000 hours a year Leisure my bad + + + align:start position:0% +2,000 hours a year Leisure my bad +leisures on the exsis they 2,000 hours + + align:start position:0% +leisures on the exsis they 2,000 hours + + + align:start position:0% +leisures on the exsis they 2,000 hours +year Leisure and have no consumption or + + align:start position:0% +year Leisure and have no consumption or + + + align:start position:0% +year Leisure and have no consumption or +take zero Leisure and have 40,000 in + + align:start position:0% +take zero Leisure and have 40,000 in + + + align:start position:0% +take zero Leisure and have 40,000 in +consumption and let's assume we're going + + align:start position:0% +consumption and let's assume we're going + + + align:start position:0% +consumption and let's assume we're going +to measure price of goods is all one so + + align:start position:0% +to measure price of goods is all one so + + + align:start position:0% +to measure price of goods is all one so +consumption is just like this + + align:start position:0% +consumption is just like this + + + align:start position:0% +consumption is just like this +consumption bundle like we talked about + + align:start position:0% +consumption bundle like we talked about + + + align:start position:0% +consumption bundle like we talked about +this numer good idea that basically we + + align:start position:0% +this numer good idea that basically we + + + align:start position:0% +this numer good idea that basically we +think of dollars and units of + + align:start position:0% +think of dollars and units of + + + align:start position:0% +think of dollars and units of +consumption + + align:start position:0% +consumption + + + align:start position:0% +consumption +interchangeably so basically consumption + + align:start position:0% +interchangeably so basically consumption + + + align:start position:0% +interchangeably so basically consumption +costs a dollar the price consumption is + + align:start position:0% +costs a dollar the price consumption is + + + align:start position:0% +costs a dollar the price consumption is +a dollar so basically the trade-off is + + align:start position:0% +a dollar so basically the trade-off is + + + align:start position:0% +a dollar so basically the trade-off is +simply for every hour I take of leisure + + align:start position:0% +simply for every hour I take of leisure + + + align:start position:0% +simply for every hour I take of leisure +I give up $20 of + + align:start position:0% +I give up $20 of + + + align:start position:0% +I give up $20 of +consumption and that leads that black + + align:start position:0% +consumption and that leads that black + + + align:start position:0% +consumption and that leads that black +line the program I just described + + align:start position:0% +line the program I just described + + + align:start position:0% +line the program I just described +changes that line as follows first of + + align:start position:0% +changes that line as follows first of + + + align:start position:0% +changes that line as follows first of +all on the leftand side if you + + align:start position:0% +all on the leftand side if you + + + align:start position:0% +all on the leftand side if you +take if you take uh first of all I'm + + align:start position:0% +take if you take uh first of all I'm + + + align:start position:0% +take if you take uh first of all I'm +sorry on the right hand side my bad on + + align:start position:0% +sorry on the right hand side my bad on + + + align:start position:0% +sorry on the right hand side my bad on +the right hand side if you take more + + align:start position:0% +the right hand side if you take more + + + align:start position:0% +the right hand side if you take more +than 17700 50 hours of + + align:start position:0% +than 17700 50 hours of + + + align:start position:0% +than 17700 50 hours of +leisure we're going to give you money + + align:start position:0% +leisure we're going to give you money + + + align:start position:0% +leisure we're going to give you money +why because if you take less than $750 + + align:start position:0% +why because if you take less than $750 + + + align:start position:0% +why because if you take less than $750 +of leisure you're going to have more + + align:start position:0% +of leisure you're going to have more + + + align:start position:0% +of leisure you're going to have more +than $5,000 already look at the X look + + align:start position:0% +than $5,000 already look at the X look + + + align:start position:0% +than $5,000 already look at the X look +at the y- AIS 750 hours of leisure at + + align:start position:0% +at the y- AIS 750 hours of leisure at + + + align:start position:0% +at the y- AIS 750 hours of leisure at +a$2 wage means you're working 250 hours + + align:start position:0% +a$2 wage means you're working 250 hours + + + align:start position:0% +a$2 wage means you're working 250 hours +mean you got 5,000 in income so your + + align:start position:0% +mean you got 5,000 in income so your + + + align:start position:0% +mean you got 5,000 in income so your +income's below + + align:start position:0% +income's below + + + align:start position:0% +income's below +$5,000 that means you must be taking + + align:start position:0% +$5,000 that means you must be taking + + + align:start position:0% +$5,000 that means you must be taking +more than 1,750 hours of Leisure for + + align:start position:0% +more than 1,750 hours of Leisure for + + + align:start position:0% +more than 1,750 hours of Leisure for +those people who are simply going to say + + align:start position:0% +those people who are simply going to say + + + align:start position:0% +those people who are simply going to say +look we're going to make sure you have + + align:start position:0% +look we're going to make sure you have + + + align:start position:0% +look we're going to make sure you have +at least + + align:start position:0% +at least + + + align:start position:0% +at least +$5,000 what does it do the budget con + + align:start position:0% +$5,000 what does it do the budget con + + + align:start position:0% +$5,000 what does it do the budget con +Str that says it becomes flat from the + + align:start position:0% +Str that says it becomes flat from the + + + align:start position:0% +Str that says it becomes flat from the +point of 1750 all the way to the point + + align:start position:0% +point of 1750 all the way to the point + + + align:start position:0% +point of 1750 all the way to the point +of 2,000 and then drops back down the + + align:start position:0% +of 2,000 and then drops back down the + + + align:start position:0% +of 2,000 and then drops back down the +new budget constraint on the right is + + align:start position:0% +new budget constraint on the right is + + + align:start position:0% +new budget constraint on the right is +the red segment it's a flat segment + + align:start position:0% +the red segment it's a flat segment + + + align:start position:0% +the red segment it's a flat segment +because we're saying no matter how much + + align:start position:0% +because we're saying no matter how much + + + align:start position:0% +because we're saying no matter how much +leure you take above 1750 you always get + + align:start position:0% +leure you take above 1750 you always get + + + align:start position:0% +leure you take above 1750 you always get +$5,000 in income we just send you a + + align:start position:0% +$5,000 in income we just send you a + + + align:start position:0% +$5,000 in income we just send you a +check for the + + align:start position:0% +check for the + + + align:start position:0% +check for the +rest like likewise we're going to pay + + align:start position:0% +rest like likewise we're going to pay + + + align:start position:0% +rest like likewise we're going to pay +for that by a tax on those who earn + + align:start position:0% +for that by a tax on those who earn + + + align:start position:0% +for that by a tax on those who earn +above + + align:start position:0% +above + + + align:start position:0% +above +$20,000 well at $20 an hour that means + + align:start position:0% +$20,000 well at $20 an hour that means + + + align:start position:0% +$20,000 well at $20 an hour that means +people who take less than a thousand + + align:start position:0% +people who take less than a thousand + + + align:start position:0% +people who take less than a thousand +hours of leisure are the ones who earn + + align:start position:0% +hours of leisure are the ones who earn + + + align:start position:0% +hours of leisure are the ones who earn +more than $20,000 so on those people + + align:start position:0% +more than $20,000 so on those people + + + align:start position:0% +more than $20,000 so on those people +were're taxing them 50% so that lowers + + align:start position:0% +were're taxing them 50% so that lowers + + + align:start position:0% +were're taxing them 50% so that lowers +the slope of the budget constraint now + + align:start position:0% +the slope of the budget constraint now + + + align:start position:0% +the slope of the budget constraint now +for every hour you work above a + + align:start position:0% +for every hour you work above a + + + align:start position:0% +for every hour you work above a +thousand you take home only $10 an + + align:start position:0% +thousand you take home only $10 an + + + align:start position:0% +thousand you take home only $10 an +hour so that lowers the opportunity cost + + align:start position:0% +hour so that lowers the opportunity cost + + + align:start position:0% +hour so that lowers the opportunity cost +of work lowers the budget constraint to + + align:start position:0% +of work lowers the budget constraint to + + + align:start position:0% +of work lowers the budget constraint to +the upper left right + + align:start position:0% +the upper left right + + + align:start position:0% +the upper left right +side okay questions about + + align:start position:0% +side okay questions about + + + align:start position:0% +side okay questions about +that okay now let's + + align:start position:0% +that okay now let's + + + align:start position:0% +that okay now let's +assume that there's three people in this + + align:start position:0% +assume that there's three people in this + + + align:start position:0% +assume that there's three people in this +world okay person + + align:start position:0% +world okay person + + + align:start position:0% +world okay person +A and B have the same utility function + + align:start position:0% +A and B have the same utility function + + + align:start position:0% +A and B have the same utility function +their utility function is U equals c to + + align:start position:0% +their utility function is U equals c to + + + align:start position:0% +their utility function is U equals c to +the 34 + + align:start position:0% +the 34 + + + align:start position:0% +the 34 +time L to the + + align:start position:0% + + + + align:start position:0% + +one4 person C has a different function + + align:start position:0% +one4 person C has a different function + + + align:start position:0% +one4 person C has a different function +they have + + align:start position:0% +they have + + + align:start position:0% +they have +C to the 1 + + align:start position:0% +C to the 1 + + + align:start position:0% +C to the 1 +nth L to the 8 + + align:start position:0% + + + + align:start position:0% + +9th okay so person C really likes + + align:start position:0% +9th okay so person C really likes + + + align:start position:0% +9th okay so person C really likes +Leisure rela to person A and B right + + align:start position:0% +Leisure rela to person A and B right + + + align:start position:0% +Leisure rela to person A and B right +person A and B have a 3/4 weight on + + align:start position:0% +person A and B have a 3/4 weight on + + + align:start position:0% +person A and B have a 3/4 weight on +consumption versus one quarter on + + align:start position:0% +consumption versus one quarter on + + + align:start position:0% +consumption versus one quarter on +Leisure person C is a one nth way to + + align:start position:0% +Leisure person C is a one nth way to + + + align:start position:0% +Leisure person C is a one nth way to +consumption Rel to eight nths on Leisure + + align:start position:0% +consumption Rel to eight nths on Leisure + + + align:start position:0% +consumption Rel to eight nths on Leisure +person C likes + + align:start position:0% +person C likes + + + align:start position:0% +person C likes +Leisure okay that's the utility + + align:start position:0% + + + + align:start position:0% + +function + + align:start position:0% +function + + + align:start position:0% +function +okay + + align:start position:0% +okay + + + align:start position:0% +okay +now in the optimal Choice + + align:start position:0% +now in the optimal Choice + + + align:start position:0% +now in the optimal Choice +set people are going to set their + + align:start position:0% +set people are going to set their + + + align:start position:0% +set people are going to set their +mrss equal to their + + align:start position:0% +mrss equal to their + + + align:start position:0% +mrss equal to their +MRT okay that's going to be the choice + + align:start position:0% +MRT okay that's going to be the choice + + + align:start position:0% +MRT okay that's going to be the choice +people are going to make in the optimal + + align:start position:0% +people are going to make in the optimal + + + align:start position:0% +people are going to make in the optimal +Choice set + + align:start position:0% +Choice set + + + align:start position:0% +Choice set +okay so basically what they're going to + + align:start position:0% +okay so basically what they're going to + + + align:start position:0% +okay so basically what they're going to +do is they're going to find given this + + align:start position:0% +do is they're going to find given this + + + align:start position:0% +do is they're going to find given this +budget constraint the one I depicted in + + align:start position:0% +budget constraint the one I depicted in + + + align:start position:0% +budget constraint the one I depicted in +figure + + align:start position:0% +figure + + + align:start position:0% +figure +238 what is their optimal + + align:start position:0% +238 what is their optimal + + + align:start position:0% +238 what is their optimal +choice and what we're going to + + align:start position:0% +choice and what we're going to + + + align:start position:0% +choice and what we're going to +see is + + align:start position:0% +see is + + + align:start position:0% +see is +that um without the government scheme + + align:start position:0% +that um without the government scheme + + + align:start position:0% +that um without the government scheme +we'll see that in figure 239 and we'll + + align:start position:0% +we'll see that in figure 239 and we'll + + + align:start position:0% +we'll see that in figure 239 and we'll +we'll you we'll solve the math and + + align:start position:0% +we'll you we'll solve the math and + + + align:start position:0% +we'll you we'll solve the math and +section of this example we'll solve the + + align:start position:0% +section of this example we'll solve the + + + align:start position:0% +section of this example we'll solve the +math in section so you can go through it + + align:start position:0% +math in section so you can go through it + + + align:start position:0% +math in section so you can go through it +but I'm showing you what the answer + + align:start position:0% +but I'm showing you what the answer + + + align:start position:0% +but I'm showing you what the answer +answer is we'll go through the math in + + align:start position:0% +answer is we'll go through the math in + + + align:start position:0% +answer is we'll go through the math in +the section you'll see person A and B + + align:start position:0% +the section you'll see person A and B + + + align:start position:0% +the section you'll see person A and B +will choose to be at that intersection + + align:start position:0% +will choose to be at that intersection + + + align:start position:0% +will choose to be at that intersection +on the left on the black line A1 B1 that + + align:start position:0% +on the left on the black line A1 B1 that + + + align:start position:0% +on the left on the black line A1 B1 that +is the choice they'll make given this + + align:start position:0% +is the choice they'll make given this + + + align:start position:0% +is the choice they'll make given this +budget constraint and given these + + align:start position:0% +budget constraint and given these + + + align:start position:0% +budget constraint and given these +preferences they will choose in figure + + align:start position:0% +preferences they will choose in figure + + + align:start position:0% +preferences they will choose in figure +239 be the A1 B1 + + align:start position:0% +239 be the A1 B1 + + + align:start position:0% +239 be the A1 B1 +intersection unsurprisingly person c + + align:start position:0% +intersection unsurprisingly person c + + + align:start position:0% +intersection unsurprisingly person c +will be choose to be way down on the + + align:start position:0% +will be choose to be way down on the + + + align:start position:0% +will be choose to be way down on the +right at the C1 intersection why because + + align:start position:0% +right at the C1 intersection why because + + + align:start position:0% +right at the C1 intersection why because +they love Leisure person C cares way + + align:start position:0% +they love Leisure person C cares way + + + align:start position:0% +they love Leisure person C cares way +about Leisure consumption it's the way + + align:start position:0% +about Leisure consumption it's the way + + + align:start position:0% +about Leisure consumption it's the way +down the right okay we'll work out the + + align:start position:0% +down the right okay we'll work out the + + + align:start position:0% +down the right okay we'll work out the +math just take it to me take take my + + align:start position:0% +math just take it to me take take my + + + align:start position:0% +math just take it to me take take my +word that's what the math + + align:start position:0% +word that's what the math + + + align:start position:0% +word that's what the math +delivers now we put in the tax and + + align:start position:0% +delivers now we put in the tax and + + + align:start position:0% +delivers now we put in the tax and +transfer scheme what happens to person C + + align:start position:0% +transfer scheme what happens to person C + + + align:start position:0% +transfer scheme what happens to person C +why do they move to + + align:start position:0% + + + + align:start position:0% + +C2 why do they move to + + align:start position:0% +C2 why do they move to + + + align:start position:0% +C2 why do they move to +C2 well if you think about it think + + align:start position:0% +C2 well if you think about it think + + + align:start position:0% +C2 well if you think about it think +about income and substitution effects + + align:start position:0% +about income and substitution effects + + + align:start position:0% +about income and substitution effects +for person C the substitution effect is + + align:start position:0% +for person C the substitution effect is + + + align:start position:0% +for person C the substitution effect is +when you're at like person C there is a + + align:start position:0% +when you're at like person C there is a + + + align:start position:0% +when you're at like person C there is a +100% tax + + align:start position:0% +100% tax + + + align:start position:0% +100% tax +on your + + align:start position:0% +on your + + + align:start position:0% +on your +earnings look at this 100% tax because + + align:start position:0% +earnings look at this 100% tax because + + + align:start position:0% +earnings look at this 100% tax because +every dollar you earn you get less in + + align:start position:0% +every dollar you earn you get less in + + + align:start position:0% +every dollar you earn you get less in +transfer substitution effect says don't + + align:start position:0% +transfer substitution effect says don't + + + align:start position:0% +transfer substitution effect says don't +work right because if you work you get + + align:start position:0% +work right because if you work you get + + + align:start position:0% +work right because if you work you get +nothing the income effect is your richer + + align:start position:0% +nothing the income effect is your richer + + + align:start position:0% +nothing the income effect is your richer +you're getting a transfer income effect + + align:start position:0% +you're getting a transfer income effect + + + align:start position:0% +you're getting a transfer income effect +also says don't work so they don't work + + align:start position:0% +also says don't work so they don't work + + + align:start position:0% +also says don't work so they don't work +turn that if you pay people not to work + + align:start position:0% +turn that if you pay people not to work + + + align:start position:0% +turn that if you pay people not to work +they won't we learned that in the + + align:start position:0% +they won't we learned that in the + + + align:start position:0% +they won't we learned that in the +Netherlands last time so all the people + + align:start position:0% +Netherlands last time so all the people + + + align:start position:0% +Netherlands last time so all the people +who were C1 go to C2 they stop + + align:start position:0% +who were C1 go to C2 they stop + + + align:start position:0% +who were C1 go to C2 they stop +working what about A1 and B1 well here + + align:start position:0% +working what about A1 and B1 well here + + + align:start position:0% +working what about A1 and B1 well here +it's + + align:start position:0% +it's + + + align:start position:0% +it's +unclear they now face a lower wage + + align:start position:0% +unclear they now face a lower wage + + + align:start position:0% +unclear they now face a lower wage +effective wage of $10 of $20 whether + + align:start position:0% +effective wage of $10 of $20 whether + + + align:start position:0% +effective wage of $10 of $20 whether +they work more or less depends on income + + align:start position:0% +they work more or less depends on income + + + align:start position:0% +they work more or less depends on income +versus substitution + + align:start position:0% +versus substitution + + + align:start position:0% +versus substitution +effects here I'm going to assume + + align:start position:0% +effects here I'm going to assume + + + align:start position:0% +effects here I'm going to assume +substitution effects + + align:start position:0% +substitution effects + + + align:start position:0% +substitution effects +dominate so they work + + align:start position:0% +dominate so they work + + + align:start position:0% +dominate so they work +less so the new equilibrium is the + + align:start position:0% +less so the new equilibrium is the + + + align:start position:0% +less so the new equilibrium is the +person C works less + + align:start position:0% +person C works less + + + align:start position:0% +person C works less +and person A and B work + + align:start position:0% +and person A and B work + + + align:start position:0% +and person A and B work +less what have we found leaks in the + + align:start position:0% +less what have we found leaks in the + + + align:start position:0% +less what have we found leaks in the +bucket we thought we could raise a bunch + + align:start position:0% +bucket we thought we could raise a bunch + + + align:start position:0% +bucket we thought we could raise a bunch +of money from taxiing and being given to + + align:start position:0% +of money from taxiing and being given to + + + align:start position:0% +of money from taxiing and being given to +C but we missed two things first of all + + align:start position:0% +C but we missed two things first of all + + + align:start position:0% +C but we missed two things first of all +A and B don't work as hard so we can't + + align:start position:0% +A and B don't work as hard so we can't + + + align:start position:0% +A and B don't work as hard so we can't +raise as much money from + + align:start position:0% +raise as much money from + + + align:start position:0% +raise as much money from +them second of all C doesn't work so + + align:start position:0% +them second of all C doesn't work so + + + align:start position:0% +them second of all C doesn't work so +hard so we need to get more money to see + + align:start position:0% +hard so we need to get more money to see + + + align:start position:0% +hard so we need to get more money to see +so if you started with 0.1 A1 B1 and C1 + + align:start position:0% +so if you started with 0.1 A1 B1 and C1 + + + align:start position:0% +so if you started with 0.1 A1 B1 and C1 +you would have a certain estimate of how + + align:start position:0% +you would have a certain estimate of how + + + align:start position:0% +you would have a certain estimate of how +much money you have to take to get + + align:start position:0% +much money you have to take to get + + + align:start position:0% +much money you have to take to get +person C1 the transfer your estimate + + align:start position:0% +person C1 the transfer your estimate + + + align:start position:0% +person C1 the transfer your estimate +would be too low why would your estimate + + align:start position:0% +would be too low why would your estimate + + + align:start position:0% +would be too low why would your estimate +be to too low because you'd miss the + + align:start position:0% +be to too low because you'd miss the + + + align:start position:0% +be to too low because you'd miss the +leakage you miss the fact that A1 and B1 + + align:start position:0% +leakage you miss the fact that A1 and B1 + + + align:start position:0% +leakage you miss the fact that A1 and B1 +going to work less so you raise less + + align:start position:0% +going to work less so you raise less + + + align:start position:0% +going to work less so you raise less +money from them and C1 is going to work + + align:start position:0% +money from them and C1 is going to work + + + align:start position:0% +money from them and C1 is going to work +less so you give more money to C1 those + + align:start position:0% +less so you give more money to C1 those + + + align:start position:0% +less so you give more money to C1 those +are the leaks that's a graphical + + align:start position:0% +are the leaks that's a graphical + + + align:start position:0% +are the leaks that's a graphical +illustration of the leaks in the bucket + + align:start position:0% +illustration of the leaks in the bucket + + + align:start position:0% +illustration of the leaks in the bucket +that is how the Leaky bucket works it + + align:start position:0% +that is how the Leaky bucket works it + + + align:start position:0% +that is how the Leaky bucket works it +causes + + align:start position:0% +causes + + + align:start position:0% +causes +taxation causes assuming substitution + + align:start position:0% +taxation causes assuming substitution + + + align:start position:0% +taxation causes assuming substitution +effects dominate taxation causes the + + align:start position:0% +effects dominate taxation causes the + + + align:start position:0% +effects dominate taxation causes the +rich to work less hard which means you + + align:start position:0% +rich to work less hard which means you + + + align:start position:0% +rich to work less hard which means you +raise less money and it causes the poor + + align:start position:0% +raise less money and it causes the poor + + + align:start position:0% +raise less money and it causes the poor +to work less hard which means you have + + align:start position:0% +to work less hard which means you have + + + align:start position:0% +to work less hard which means you have +to spend more money and those the tour + + align:start position:0% +to spend more money and those the tour + + + align:start position:0% +to spend more money and those the tour +so leaked that was very fast and + + align:start position:0% +so leaked that was very fast and + + + align:start position:0% +so leaked that was very fast and +graphical in section you go through the + + align:start position:0% +graphical in section you go through the + + + align:start position:0% +graphical in section you go through the +math but that just gives you a sense of + + align:start position:0% +math but that just gives you a sense of + + + align:start position:0% +math but that just gives you a sense of +how the leakages work we'll follow up on + + align:start position:0% +how the leakages work we'll follow up on + + + align:start position:0% +how the leakages work we'll follow up on +Monday \ No newline at end of file diff --git a/8ssjKR7nNck.txt b/8ssjKR7nNck.txt new file mode 100644 index 0000000000000000000000000000000000000000..7f334dceac8561fc04694aebad2621b7aa62be4a --- /dev/null +++ b/8ssjKR7nNck.txt @@ -0,0 +1,8267 @@ +align:start position:0% + +um let's get started this is uh + + align:start position:0% +um let's get started this is uh + + + align:start position:0% +um let's get started this is uh +1401 uh microeconomics uh the uh and um + + align:start position:0% +1401 uh microeconomics uh the uh and um + + + align:start position:0% +1401 uh microeconomics uh the uh and um +I'm professor John + + align:start position:0% +I'm professor John + + + align:start position:0% +I'm professor John +Gruber now couple notes about the course + + align:start position:0% +Gruber now couple notes about the course + + + align:start position:0% +Gruber now couple notes about the course +uh there's a distinct policy angle to + + align:start position:0% +uh there's a distinct policy angle to + + + align:start position:0% +uh there's a distinct policy angle to +this course um I think personally what + + align:start position:0% +this course um I think personally what + + + align:start position:0% +this course um I think personally what +makes economics most exciting is it can + + align:start position:0% +makes economics most exciting is it can + + + align:start position:0% +makes economics most exciting is it can +you you can use it to think + + align:start position:0% +you you can use it to think + + + align:start position:0% +you you can use it to think +intelligently about the problems that + + align:start position:0% +intelligently about the problems that + + + align:start position:0% +intelligently about the problems that +policy makers face every day as they try + + align:start position:0% +policy makers face every day as they try + + + align:start position:0% +policy makers face every day as they try +to decide how to make the economy work + + align:start position:0% +to decide how to make the economy work + + + align:start position:0% +to decide how to make the economy work +the best for its citizens um in fact I + + align:start position:0% +the best for its citizens um in fact I + + + align:start position:0% +the best for its citizens um in fact I +teach a whole course about this called + + align:start position:0% +teach a whole course about this called + + + align:start position:0% +teach a whole course about this called +1441 uh but I'm going to bring some of + + align:start position:0% +1441 uh but I'm going to bring some of + + + align:start position:0% +1441 uh but I'm going to bring some of +those insights into this class and use + + align:start position:0% +those insights into this class and use + + + align:start position:0% +those insights into this class and use +policy based examples and things like + + align:start position:0% +policy based examples and things like + + + align:start position:0% +policy based examples and things like +that to try to motivate uh and organize + + align:start position:0% +that to try to motivate uh and organize + + + align:start position:0% +that to try to motivate uh and organize +our thinking about + + align:start position:0% +our thinking about + + + align:start position:0% +our thinking about +economics um lastly uh three points + + align:start position:0% +economics um lastly uh three points + + + align:start position:0% +economics um lastly uh three points +about my teaching style first of all I + + align:start position:0% +about my teaching style first of all I + + + align:start position:0% +about my teaching style first of all I +don't write everything on the board uh + + align:start position:0% +don't write everything on the board uh + + + align:start position:0% +don't write everything on the board uh +for the Freshman here we're not in high + + align:start position:0% +for the Freshman here we're not in high + + + align:start position:0% +for the Freshman here we're not in high +schoool anymore you need to pay + + align:start position:0% +schoool anymore you need to pay + + + align:start position:0% +schoool anymore you need to pay +attention and listen to what I say not + + align:start position:0% +attention and listen to what I say not + + + align:start position:0% +attention and listen to what I say not +just what I write um so it's important + + align:start position:0% +just what I write um so it's important + + + align:start position:0% +just what I write um so it's important +to remember that um uh uh the second + + align:start position:0% +to remember that um uh uh the second + + + align:start position:0% +to remember that um uh uh the second +point is as you can tell I talk really + + align:start position:0% +point is as you can tell I talk really + + + align:start position:0% +point is as you can tell I talk really +fast and my handwriting is really bad + + align:start position:0% +fast and my handwriting is really bad + + + align:start position:0% +fast and my handwriting is really bad +okay so please please don't be afraid to + + align:start position:0% +okay so please please don't be afraid to + + + align:start position:0% +okay so please please don't be afraid to +ask what the hell I just said or wrote + + align:start position:0% +ask what the hell I just said or wrote + + + align:start position:0% +ask what the hell I just said or wrote +okay there is if you don't know chances + + align:start position:0% +okay there is if you don't know chances + + + align:start position:0% +okay there is if you don't know chances +are at least 40% of the class doesn't + + align:start position:0% +are at least 40% of the class doesn't + + + align:start position:0% +are at least 40% of the class doesn't +know either we'll learn later this + + align:start position:0% +know either we'll learn later this + + + align:start position:0% +know either we'll learn later this +semester about the con a public good a + + align:start position:0% +semester about the con a public good a + + + align:start position:0% +semester about the con a public good a +public good is something you do which + + align:start position:0% +public good is something you do which + + + align:start position:0% +public good is something you do which +has a personal cost and a social benefit + + align:start position:0% +has a personal cost and a social benefit + + + align:start position:0% +has a personal cost and a social benefit +I understand raising your raising your + + align:start position:0% +I understand raising your raising your + + + align:start position:0% +I understand raising your raising your +hand in a class as large as this can be + + align:start position:0% +hand in a class as large as this can be + + + align:start position:0% +hand in a class as large as this can be +intimidating but remember in doing so + + align:start position:0% +intimidating but remember in doing so + + + align:start position:0% +intimidating but remember in doing so +you're not just helping yourself you're + + align:start position:0% +you're not just helping yourself you're + + + align:start position:0% +you're not just helping yourself you're +helping your fellow classmates so please + + align:start position:0% +helping your fellow classmates so please + + + align:start position:0% +helping your fellow classmates so please +don't lean and Whisper loudly what the + + align:start position:0% +don't lean and Whisper loudly what the + + + align:start position:0% +don't lean and Whisper loudly what the +hell did you just say to the person next + + align:start position:0% +hell did you just say to the person next + + + align:start position:0% +hell did you just say to the person next +to you raise your hand and ask me + + align:start position:0% +to you raise your hand and ask me + + + align:start position:0% +to you raise your hand and ask me +because if you didn't understand many + + align:start position:0% +because if you didn't understand many + + + align:start position:0% +because if you didn't understand many +other people didn't as well more + + align:start position:0% +other people didn't as well more + + + align:start position:0% +other people didn't as well more +generally it's hard to get class + + align:start position:0% +generally it's hard to get class + + + align:start position:0% +generally it's hard to get class +participation in a class this large but + + align:start position:0% +participation in a class this large but + + + align:start position:0% +participation in a class this large but +I really encourage people to participate + + align:start position:0% +I really encourage people to participate + + + align:start position:0% +I really encourage people to participate +as much as + + align:start position:0% +as much as + + + align:start position:0% +as much as +possible I've never had a year in this + + align:start position:0% +possible I've never had a year in this + + + align:start position:0% +possible I've never had a year in this +class where there's been too much + + align:start position:0% +class where there's been too much + + + align:start position:0% +class where there's been too much +participation I've had every single year + + align:start position:0% +participation I've had every single year + + + align:start position:0% +participation I've had every single year +too little participation so please + + align:start position:0% +too little participation so please + + + align:start position:0% +too little participation so please +follow up with questions uh things like + + align:start position:0% +follow up with questions uh things like + + + align:start position:0% +follow up with questions uh things like +that and then finally the third point + + align:start position:0% +that and then finally the third point + + + align:start position:0% +that and then finally the third point +about my teaching style is I have a bad + + align:start position:0% +about my teaching style is I have a bad + + + align:start position:0% +about my teaching style is I have a bad +tendency to use the term guys in a + + align:start position:0% +tendency to use the term guys in a + + + align:start position:0% +tendency to use the term guys in a +gender neutral sense so when I say guys + + align:start position:0% +gender neutral sense so when I say guys + + + align:start position:0% +gender neutral sense so when I say guys +I don't mean men I mean economic agents + + align:start position:0% +I don't mean men I mean economic agents + + + align:start position:0% +I don't mean men I mean economic agents +people everyone and I'm sorry guys has a + + align:start position:0% +people everyone and I'm sorry guys has a + + + align:start position:0% +people everyone and I'm sorry guys has a +gendered word often I don't mean it that + + align:start position:0% +gendered word often I don't mean it that + + + align:start position:0% +gendered word often I don't mean it that +way it's just kind of a economist talk + + align:start position:0% +way it's just kind of a economist talk + + + align:start position:0% +way it's just kind of a economist talk +for for economic agents we call them + + align:start position:0% +for for economic agents we call them + + + align:start position:0% +for for economic agents we call them +guys what we're going to do today is + + align:start position:0% +guys what we're going to do today is + + + align:start position:0% +guys what we're going to do today is +talk about what is microeconomics what + + align:start position:0% +talk about what is microeconomics what + + + align:start position:0% +talk about what is microeconomics what +are you going to learn in this course + + align:start position:0% +are you going to learn in this course + + + align:start position:0% +are you going to learn in this course +what is the basic field about and then + + align:start position:0% +what is the basic field about and then + + + align:start position:0% +what is the basic field about and then +we'll dive in next time into actually + + align:start position:0% +we'll dive in next time into actually + + + align:start position:0% +we'll dive in next time into actually +starting to learn about the models that + + align:start position:0% +starting to learn about the models that + + + align:start position:0% +starting to learn about the models that +make up basic + + align:start position:0% +make up basic + + + align:start position:0% +make up basic +microeconomics um + + align:start position:0% +microeconomics um + + + align:start position:0% +microeconomics um +microeconomics is fundamentally in a + + align:start position:0% +microeconomics is fundamentally in a + + + align:start position:0% +microeconomics is fundamentally in a +sentence the study of how individuals + + align:start position:0% +sentence the study of how individuals + + + align:start position:0% +sentence the study of how individuals +and firms make themselves as well off as + + align:start position:0% +and firms make themselves as well off as + + + align:start position:0% +and firms make themselves as well off as +possible in a world of scarcity it's how + + align:start position:0% +possible in a world of scarcity it's how + + + align:start position:0% +possible in a world of scarcity it's how +individuals and firms make themselves as + + align:start position:0% +individuals and firms make themselves as + + + align:start position:0% +individuals and firms make themselves as +well off as possible in a world of + + align:start position:0% +well off as possible in a world of + + + align:start position:0% +well off as possible in a world of +scarcity scarcity is key the core of + + align:start position:0% +scarcity scarcity is key the core of + + + align:start position:0% +scarcity scarcity is key the core of +microeconomics is constrained + + align:start position:0% +microeconomics is constrained + + + align:start position:0% +microeconomics is constrained +optimization basically individuals or + + align:start position:0% +optimization basically individuals or + + + align:start position:0% +optimization basically individuals or +firms assessing the tradeoffs they face + + align:start position:0% +firms assessing the tradeoffs they face + + + align:start position:0% +firms assessing the tradeoffs they face +every day in the decisions they make and + + align:start position:0% +every day in the decisions they make and + + + align:start position:0% +every day in the decisions they make and +then trying to decide the best decision + + align:start position:0% +then trying to decide the best decision + + + align:start position:0% +then trying to decide the best decision +given those + + align:start position:0% +given those + + + align:start position:0% +given those +tradeoffs so that is microeconomics is + + align:start position:0% +tradeoffs so that is microeconomics is + + + align:start position:0% +tradeoffs so that is microeconomics is +really about trade-offs mic economics is + + align:start position:0% +really about trade-offs mic economics is + + + align:start position:0% +really about trade-offs mic economics is +really about you can't have it all so + + align:start position:0% +really about you can't have it all so + + + align:start position:0% +really about you can't have it all so +what are you going to do with what you + + align:start position:0% +what are you going to do with what you + + + align:start position:0% +what are you going to do with what you +can have how are you best going to use + + align:start position:0% +can have how are you best going to use + + + align:start position:0% +can have how are you best going to use +your limited + + align:start position:0% +your limited + + + align:start position:0% +your limited +resources and the key concept behind all + + align:start position:0% +resources and the key concept behind all + + + align:start position:0% +resources and the key concept behind all +this the sort of probably the I'm going + + align:start position:0% +this the sort of probably the I'm going + + + align:start position:0% +this the sort of probably the I'm going +to say about 100 times this is one of + + align:start position:0% +to say about 100 times this is one of + + + align:start position:0% +to say about 100 times this is one of +the most important Concepts in economics + + align:start position:0% +the most important Concepts in economics + + + align:start position:0% +the most important Concepts in economics +I'm sorry about that but this is really + + align:start position:0% +I'm sorry about that but this is really + + + align:start position:0% +I'm sorry about that but this is really +one of the most important Concepts in + + align:start position:0% +one of the most important Concepts in + + + align:start position:0% +one of the most important Concepts in +economics is the concept of opportunity + + align:start position:0% + + + + align:start position:0% + +cost opportunity cost + + align:start position:0% +cost opportunity cost + + + align:start position:0% +cost opportunity cost +okay and opportunity cost is the notion + + align:start position:0% +okay and opportunity cost is the notion + + + align:start position:0% +okay and opportunity cost is the notion +that every + + align:start position:0% +that every + + + align:start position:0% +that every +action or in action has cost in terms of + + align:start position:0% +action or in action has cost in terms of + + + align:start position:0% +action or in action has cost in terms of +what you could have done instead in + + align:start position:0% +what you could have done instead in + + + align:start position:0% +what you could have done instead in +terms of the next best + + align:start position:0% +terms of the next best + + + align:start position:0% +terms of the next best +opportunity if you buy a shirt you are + + align:start position:0% +opportunity if you buy a shirt you are + + + align:start position:0% +opportunity if you buy a shirt you are +forgoing spending that money on buying + + align:start position:0% +forgoing spending that money on buying + + + align:start position:0% +forgoing spending that money on buying +something else so if you're deciding + + align:start position:0% +something else so if you're deciding + + + align:start position:0% +something else so if you're deciding +between shirts and pants you buy the + + align:start position:0% +between shirts and pants you buy the + + + align:start position:0% +between shirts and pants you buy the +shirt you're for going buying the pair + + align:start position:0% +shirt you're for going buying the pair + + + align:start position:0% +shirt you're for going buying the pair +of + + align:start position:0% +of + + + align:start position:0% +of +pants if you + + align:start position:0% +pants if you + + + align:start position:0% +pants if you +study if you spend all night studying + + align:start position:0% +study if you spend all night studying + + + align:start position:0% +study if you spend all night studying +you're forg going the opportunity to go + + align:start position:0% +you're forg going the opportunity to go + + + align:start position:0% +you're forg going the opportunity to go +see a band you like in concert and vice + + align:start position:0% +see a band you like in concert and vice + + + align:start position:0% +see a band you like in concert and vice +versa every action you take is a + + align:start position:0% +versa every action you take is a + + + align:start position:0% +versa every action you take is a +trade-off every decision you make + + align:start position:0% +trade-off every decision you make + + + align:start position:0% +trade-off every decision you make +involves a trade-off because there's + + align:start position:0% +involves a trade-off because there's + + + align:start position:0% +involves a trade-off because there's +always an opportunity cost there's + + align:start position:0% +always an opportunity cost there's + + + align:start position:0% +always an opportunity cost there's +always something you could have done + + align:start position:0% +always something you could have done + + + align:start position:0% +always something you could have done +instead + + align:start position:0% + + + + align:start position:0% + +yeah great question um actually let me + + align:start position:0% +yeah great question um actually let me + + + align:start position:0% +yeah great question um actually let me +come back to that in one minute I want + + align:start position:0% +come back to that in one minute I want + + + align:start position:0% +come back to that in one minute I want +to come back to that or five minutes um + + align:start position:0% +to come back to that or five minutes um + + + align:start position:0% +to come back to that or five minutes um +okay so this is why economics is called + + align:start position:0% +okay so this is why economics is called + + + align:start position:0% +okay so this is why economics is called +the Dismal science we're called the + + align:start position:0% +the Dismal science we're called the + + + align:start position:0% +the Dismal science we're called the +Dismal science because the role of the + + align:start position:0% +Dismal science because the role of the + + + align:start position:0% +Dismal science because the role of the +economist is to basically say well you + + align:start position:0% +economist is to basically say well you + + + align:start position:0% +economist is to basically say well you +think that's free but it's not you think + + align:start position:0% +think that's free but it's not you think + + + align:start position:0% +think that's free but it's not you think +you can just relax and watch TV but you + + align:start position:0% +you can just relax and watch TV but you + + + align:start position:0% +you can just relax and watch TV but you +know by watching TV you're giving up the + + align:start position:0% +know by watching TV you're giving up the + + + align:start position:0% +know by watching TV you're giving up the +opportunity to study the opportunity to + + align:start position:0% +opportunity to study the opportunity to + + + align:start position:0% +opportunity to study the opportunity to +go out see a concert or the opportunity + + align:start position:0% +go out see a concert or the opportunity + + + align:start position:0% +go out see a concert or the opportunity +to do something else okay so that's why + + align:start position:0% +to do something else okay so that's why + + + align:start position:0% +to do something else okay so that's why +they call disal science now some people + + align:start position:0% +they call disal science now some people + + + align:start position:0% +they call disal science now some people +may call dismal I call it fun and maybe + + align:start position:0% +may call dismal I call it fun and maybe + + + align:start position:0% +may call dismal I call it fun and maybe +that's because I was an MIT + + align:start position:0% +that's because I was an MIT + + + align:start position:0% +that's because I was an MIT +undergraduate and what is an engineering + + align:start position:0% +undergraduate and what is an engineering + + + align:start position:0% +undergraduate and what is an engineering +school but the land of constrainted + + align:start position:0% +school but the land of constrainted + + + align:start position:0% +school but the land of constrainted +optimization that's what engineering and + + align:start position:0% +optimization that's what engineering and + + + align:start position:0% +optimization that's what engineering and +science is it's all about what + + align:start position:0% +science is it's all about what + + + align:start position:0% +science is it's all about what +engineering is tra and optimization what + + align:start position:0% +engineering is tra and optimization what + + + align:start position:0% +engineering is tra and optimization what +better example could there be in the + + align:start position:0% +better example could there be in the + + + align:start position:0% +better example could there be in the +two7 contests you're given a set of + + align:start position:0% +two7 contests you're given a set of + + + align:start position:0% +two7 contests you're given a set of +materials and asked to build something + + align:start position:0% +materials and asked to build something + + + align:start position:0% +materials and asked to build something +that's a constrained optimization + + align:start position:0% +that's a constrained optimization + + + align:start position:0% +that's a constrained optimization +exercise indeed economics was invented + + align:start position:0% +exercise indeed economics was invented + + + align:start position:0% +exercise indeed economics was invented +modern economics invented at MIT by The + + align:start position:0% +modern economics invented at MIT by The + + + align:start position:0% +modern economics invented at MIT by The +Economist Paul Samuelson who essentially + + align:start position:0% +Economist Paul Samuelson who essentially + + + align:start position:0% +Economist Paul Samuelson who essentially +said the mathematics that science + + align:start position:0% +said the mathematics that science + + + align:start position:0% +said the mathematics that science +Engineers use can be applied to analyze + + align:start position:0% +Engineers use can be applied to analyze + + + align:start position:0% +Engineers use can be applied to analyze +really the sort of essay likee approach + + align:start position:0% +really the sort of essay likee approach + + + align:start position:0% +really the sort of essay likee approach +that people had taken economics before + + align:start position:0% +that people had taken economics before + + + align:start position:0% +that people had taken economics before +him so he basically brought the tools of + + align:start position:0% +him so he basically brought the tools of + + + align:start position:0% +him so he basically brought the tools of +science to economics and basically + + align:start position:0% +science to economics and basically + + + align:start position:0% +science to economics and basically +developed the course I'll teach today + + align:start position:0% +developed the course I'll teach today + + + align:start position:0% +developed the course I'll teach today +and the course that's taught all over + + align:start position:0% +and the course that's taught all over + + + align:start position:0% +and the course that's taught all over +the world was developed right here at + + align:start position:0% +the world was developed right here at + + + align:start position:0% +the world was developed right here at +MIT modern economics was born here + + align:start position:0% +MIT modern economics was born here + + + align:start position:0% +MIT modern economics was born here +because we introduced the tools of + + align:start position:0% +because we introduced the tools of + + + align:start position:0% +because we introduced the tools of +constraint + + align:start position:0% +constraint + + + align:start position:0% +constraint +optimization now oh over here I'm + + align:start position:0% +optimization now oh over here I'm + + + align:start position:0% +optimization now oh over here I'm +usually going to try to do like an + + align:start position:0% +usually going to try to do like an + + + align:start position:0% +usually going to try to do like an +outline of what we're covering so we + + align:start position:0% +outline of what we're covering so we + + + align:start position:0% +outline of what we're covering so we +talked about course details what is + + align:start position:0% +talked about course details what is + + + align:start position:0% +talked about course details what is +micro just did now let's talk about how + + align:start position:0% +micro just did now let's talk about how + + + align:start position:0% +micro just did now let's talk about how +we do that what economics does which is + + align:start position:0% +we do that what economics does which is + + + align:start position:0% +we do that what economics does which is +we use models and I'm talk about a model + + align:start position:0% +we use models and I'm talk about a model + + + align:start position:0% +we use models and I'm talk about a model +of supply and + + align:start position:0% + + + + align:start position:0% + +demand how do we actually teach you all + + align:start position:0% +demand how do we actually teach you all + + + align:start position:0% +demand how do we actually teach you all +about these tradeoffs + + align:start position:0% +about these tradeoffs + + + align:start position:0% +about these tradeoffs +okay the way we do it is by building + + align:start position:0% +okay the way we do it is by building + + + align:start position:0% +okay the way we do it is by building +simplified models okay what is a Model A + + align:start position:0% +simplified models okay what is a Model A + + + align:start position:0% +simplified models okay what is a Model A +model is technically the description of + + align:start position:0% +model is technically the description of + + + align:start position:0% +model is technically the description of +any relationship between two or more + + align:start position:0% +any relationship between two or more + + + align:start position:0% +any relationship between two or more +variables is a + + align:start position:0% +variables is a + + + align:start position:0% +variables is a +model um now but unlike explaining + + align:start position:0% +model um now but unlike explaining + + + align:start position:0% +model um now but unlike explaining +relationship between energy and mass we + + align:start position:0% +relationship between energy and mass we + + + align:start position:0% +relationship between energy and mass we +do not have scientific laws and + + align:start position:0% +do not have scientific laws and + + + align:start position:0% +do not have scientific laws and +constants in our universe okay economics + + align:start position:0% +constants in our universe okay economics + + + align:start position:0% +constants in our universe okay economics +is as much as we hate to say it not a + + align:start position:0% +is as much as we hate to say it not a + + + align:start position:0% +is as much as we hate to say it not a +real science it is a social science + + align:start position:0% +real science it is a social science + + + align:start position:0% +real science it is a social science +which means that basically we don't have + + align:start position:0% +which means that basically we don't have + + + align:start position:0% +which means that basically we don't have +rigid laws that we can write down say + + align:start position:0% +rigid laws that we can write down say + + + align:start position:0% +rigid laws that we can write down say +they're all they're everywhere + + align:start position:0% +they're all they're everywhere + + + align:start position:0% +they're all they're everywhere +applicable okay we we have to use models + + align:start position:0% +applicable okay we we have to use models + + + align:start position:0% +applicable okay we we have to use models +to basically try to explain the world as + + align:start position:0% +to basically try to explain the world as + + + align:start position:0% +to basically try to explain the world as +much as we can and so in doing so we + + align:start position:0% +much as we can and so in doing so we + + + align:start position:0% +much as we can and so in doing so we +have to make a set of simplifying + + align:start position:0% +have to make a set of simplifying + + + align:start position:0% +have to make a set of simplifying +assumptions a set of simplifying + + align:start position:0% +assumptions a set of simplifying + + + align:start position:0% +assumptions a set of simplifying +assumptions to try to essentially trade + + align:start position:0% +assumptions to try to essentially trade + + + align:start position:0% +assumptions to try to essentially trade +off two + + align:start position:0% +off two + + + align:start position:0% +off two +goals one goal is to explain as much as + + align:start position:0% +goals one goal is to explain as much as + + + align:start position:0% +goals one goal is to explain as much as +we can the other goal is to have + + align:start position:0% +we can the other goal is to have + + + align:start position:0% +we can the other goal is to have +parsimonious models that I can teach + + align:start position:0% +parsimonious models that I can teach + + + align:start position:0% +parsimonious models that I can teach +you okay the more complicated the model + + align:start position:0% +you okay the more complicated the model + + + align:start position:0% +you okay the more complicated the model +gets the harder it is to teach the + + align:start position:0% +gets the harder it is to teach the + + + align:start position:0% +gets the harder it is to teach the +harder it is to solve this comes to the + + align:start position:0% +harder it is to solve this comes to the + + + align:start position:0% +harder it is to solve this comes to the +earlier question about are you really + + align:start position:0% +earlier question about are you really + + + align:start position:0% +earlier question about are you really +just trading off two goods well of + + align:start position:0% +just trading off two goods well of + + + align:start position:0% +just trading off two goods well of +course you're never just trading off two + + align:start position:0% +course you're never just trading off two + + + align:start position:0% +course you're never just trading off two +goods but we're going to write our + + align:start position:0% +goods but we're going to write our + + + align:start position:0% +goods but we're going to write our +models like you are and it's going to + + align:start position:0% +models like you are and it's going to + + + align:start position:0% +models like you are and it's going to +turn out that gives you all the + + align:start position:0% +turn out that gives you all the + + + align:start position:0% +turn out that gives you all the +intuition you need for a model with this + + align:start position:0% +intuition you need for a model with this + + + align:start position:0% +intuition you need for a model with this +three or four Goods it's just a lot + + align:start position:0% +three or four Goods it's just a lot + + + align:start position:0% +three or four Goods it's just a lot +easier math so it turns out everything + + align:start position:0% +easier math so it turns out everything + + + align:start position:0% +easier math so it turns out everything +you learn in the model with two goods + + align:start position:0% +you learn in the model with two goods + + + align:start position:0% +you learn in the model with two goods +tells you everything you need to know + + align:start position:0% +tells you everything you need to know + + + align:start position:0% +tells you everything you need to know +for a model with n Goods just with + + align:start position:0% +for a model with n Goods just with + + + align:start position:0% +for a model with n Goods just with +easier math so that's the kind of + + align:start position:0% +easier math so that's the kind of + + + align:start position:0% +easier math so that's the kind of +simplifying assumption that's a + + align:start position:0% +simplifying assumption that's a + + + align:start position:0% +simplifying assumption that's a +fairly um uh that's a fairly uh + + align:start position:0% +fairly um uh that's a fairly uh + + + align:start position:0% +fairly um uh that's a fairly uh +non-offensive simplifying assumption + + align:start position:0% +non-offensive simplifying assumption + + + align:start position:0% +non-offensive simplifying assumption +think it doesn't really change anything + + align:start position:0% +think it doesn't really change anything + + + align:start position:0% +think it doesn't really change anything +we'll make other simplifying assumptions + + align:start position:0% +we'll make other simplifying assumptions + + + align:start position:0% +we'll make other simplifying assumptions +which are noxious and offensive and + + align:start position:0% +which are noxious and offensive and + + + align:start position:0% +which are noxious and offensive and +we'll talk about those and if you are + + align:start position:0% +we'll talk about those and if you are + + + align:start position:0% +we'll talk about those and if you are +offended by them and bothered and want + + align:start position:0% +offended by them and bothered and want + + + align:start position:0% +offended by them and bothered and want +to see what happens without those + + align:start position:0% +to see what happens without those + + + align:start position:0% +to see what happens without those +assumptions then that's exactly why you + + align:start position:0% +assumptions then that's exactly why you + + + align:start position:0% +assumptions then that's exactly why you +should be economics major because that's + + align:start position:0% +should be economics major because that's + + + align:start position:0% +should be economics major because that's +we go on and do in the rest of the + + align:start position:0% +we go on and do in the rest of the + + + align:start position:0% +we go on and do in the rest of the +classes say okay now let's move on from + + align:start position:0% +classes say okay now let's move on from + + + align:start position:0% +classes say okay now let's move on from +these simplified models add some + + align:start position:0% +these simplified models add some + + + align:start position:0% +these simplified models add some +richness and see what it does to the + + align:start position:0% +richness and see what it does to the + + + align:start position:0% +richness and see what it does to the +world okay uh the statistician George + + align:start position:0% +world okay uh the statistician George + + + align:start position:0% +world okay uh the statistician George +box uh once wrote that all models are + + align:start position:0% +box uh once wrote that all models are + + + align:start position:0% +box uh once wrote that all models are +wrong but some are useful okay okay and + + align:start position:0% +wrong but some are useful okay okay and + + + align:start position:0% +wrong but some are useful okay okay and +that's exactly what we're going to try + + align:start position:0% +that's exactly what we're going to try + + + align:start position:0% +that's exactly what we're going to try +to work with today okay when I teach you + + align:start position:0% +to work with today okay when I teach you + + + align:start position:0% +to work with today okay when I teach you +economics I'm going to try to teach it + + align:start position:0% +economics I'm going to try to teach it + + + align:start position:0% +economics I'm going to try to teach it +to you on three levels okay the first is + + align:start position:0% +to you on three levels okay the first is + + + align:start position:0% +to you on three levels okay the first is +word MIT is + + align:start position:0% +word MIT is + + + align:start position:0% +word MIT is +mathematical the second is graphical and + + align:start position:0% +mathematical the second is graphical and + + + align:start position:0% +mathematical the second is graphical and +the third is + + align:start position:0% +the third is + + + align:start position:0% +the third is +intuitive really if you want to succeed + + align:start position:0% +intuitive really if you want to succeed + + + align:start position:0% +intuitive really if you want to succeed +in this class you need to understand all + + align:start position:0% +in this class you need to understand all + + + align:start position:0% +in this class you need to understand all +three now not every model will I use all + + align:start position:0% +three now not every model will I use all + + + align:start position:0% +three now not every model will I use all +three but you want to understand all + + align:start position:0% +three but you want to understand all + + + align:start position:0% +three but you want to understand all +three of those Concepts to really + + align:start position:0% +three of those Concepts to really + + + align:start position:0% +three of those Concepts to really +understand the material we're learning + + align:start position:0% +understand the material we're learning + + + align:start position:0% +understand the material we're learning +here and and we'll start with the model + + align:start position:0% +here and and we'll start with the model + + + align:start position:0% +here and and we'll start with the model +of supply and demand the very first + + align:start position:0% +of supply and demand the very first + + + align:start position:0% +of supply and demand the very first +economic model developed by Adam Smith + + align:start position:0% +economic model developed by Adam Smith + + + align:start position:0% +economic model developed by Adam Smith +in 1776 in the book that was sort of the + + align:start position:0% +in 1776 in the book that was sort of the + + + align:start position:0% +in 1776 in the book that was sort of the +founding of Economics The Wealth of + + align:start position:0% +founding of Economics The Wealth of + + + align:start position:0% +founding of Economics The Wealth of +Nations Adam Smith asked the question um + + align:start position:0% +Nations Adam Smith asked the question um + + + align:start position:0% +Nations Adam Smith asked the question um +think about two goods think about water + + align:start position:0% +think about two goods think about water + + + align:start position:0% +think about two goods think about water +and think about + + align:start position:0% +and think about + + + align:start position:0% +and think about +diamonds okay nothing is more essential + + align:start position:0% +diamonds okay nothing is more essential + + + align:start position:0% +diamonds okay nothing is more essential +for life than water we cannot function + + align:start position:0% +for life than water we cannot function + + + align:start position:0% +for life than water we cannot function +without it nothing is probably less + + align:start position:0% +without it nothing is probably less + + + align:start position:0% +without it nothing is probably less +essential for life than diamonds + + align:start position:0% +essential for life than diamonds + + + align:start position:0% +essential for life than diamonds +especially back then when diamonds + + align:start position:0% +especially back then when diamonds + + + align:start position:0% +especially back then when diamonds +didn't have industrial uses they were + + align:start position:0% +didn't have industrial uses they were + + + align:start position:0% +didn't have industrial uses they were +just + + align:start position:0% +just + + + align:start position:0% +just +bobbles okay water is clearly just + + align:start position:0% +bobbles okay water is clearly just + + + align:start position:0% +bobbles okay water is clearly just +essential diamonds aren't yet the price + + align:start position:0% +essential diamonds aren't yet the price + + + align:start position:0% +essential diamonds aren't yet the price +of diamonds is very high and water is + + align:start position:0% +of diamonds is very high and water is + + + align:start position:0% +of diamonds is very high and water is +essentially free he asked how could this + + align:start position:0% +essentially free he asked how could this + + + align:start position:0% +essentially free he asked how could this +be and the answer is because what I've + + align:start position:0% +be and the answer is because what I've + + + align:start position:0% +be and the answer is because what I've +just described is only one half of the + + align:start position:0% +just described is only one half of the + + + align:start position:0% +just described is only one half of the +model of where we get the price of water + + align:start position:0% +model of where we get the price of water + + + align:start position:0% +model of where we get the price of water +or diamonds I've described the + + align:start position:0% +or diamonds I've described the + + + align:start position:0% +or diamonds I've described the +demand I've describe the demand for + + align:start position:0% +demand I've describe the demand for + + + align:start position:0% +demand I've describe the demand for +water and diamonds I've said the demand + + align:start position:0% +water and diamonds I've said the demand + + + align:start position:0% +water and diamonds I've said the demand +for water is much much larger than the + + align:start position:0% +for water is much much larger than the + + + align:start position:0% +for water is much much larger than the +demand for diamonds + + align:start position:0% +demand for diamonds + + + align:start position:0% +demand for diamonds +what I haven't talked about is the + + align:start position:0% +what I haven't talked about is the + + + align:start position:0% +what I haven't talked about is the +supply which is the supply of water is + + align:start position:0% +supply which is the supply of water is + + + align:start position:0% +supply which is the supply of water is +even more Rel the supply of diamonds + + align:start position:0% +even more Rel the supply of diamonds + + + align:start position:0% +even more Rel the supply of diamonds +water is everywhere diamonds are rare to + + align:start position:0% +water is everywhere diamonds are rare to + + + align:start position:0% +water is everywhere diamonds are rare to +find and what Adam Smith said is that + + align:start position:0% +find and what Adam Smith said is that + + + align:start position:0% +find and what Adam Smith said is that +while the demand for diamonds may not be + + align:start position:0% +while the demand for diamonds may not be + + + align:start position:0% +while the demand for diamonds may not be +as high as the demand for water the + + align:start position:0% +as high as the demand for water the + + + align:start position:0% +as high as the demand for water the +supply of diamonds is much much smaller + + align:start position:0% +supply of diamonds is much much smaller + + + align:start position:0% +supply of diamonds is much much smaller +than the supply of water and that is why + + align:start position:0% +than the supply of water and that is why + + + align:start position:0% +than the supply of water and that is why +you could end up with a good that's + + align:start position:0% +you could end up with a good that's + + + align:start position:0% +you could end up with a good that's +inherently less valuable to life having + + align:start position:0% +inherently less valuable to life having + + + align:start position:0% +inherently less valuable to life having +a higher price + + align:start position:0% +a higher price + + + align:start position:0% +a higher price +okay and Smith's point is you can't just + + align:start position:0% +okay and Smith's point is you can't just + + + align:start position:0% +okay and Smith's point is you can't just +think of supply and demand and isolation + + align:start position:0% +think of supply and demand and isolation + + + align:start position:0% +think of supply and demand and isolation +you need to think of them uh together um + + align:start position:0% +you need to think of them uh together um + + + align:start position:0% +you need to think of them uh together um +is uh oh Pedro could you grab me a copy + + align:start position:0% +is uh oh Pedro could you grab me a copy + + + align:start position:0% +is uh oh Pedro could you grab me a copy +of the handout fix um okay so that's + + align:start position:0% +of the handout fix um okay so that's + + + align:start position:0% +of the handout fix um okay so that's +sort of the + + align:start position:0% +sort of the + + + align:start position:0% +sort of the +intuition that's the intuition Spider + + align:start position:0% +intuition that's the intuition Spider + + + align:start position:0% +intuition that's the intuition Spider +Man model now let's talk about the + + align:start position:0% +Man model now let's talk about the + + + align:start position:0% +Man model now let's talk about the +graphics and the math okay so now let's + + align:start position:0% +graphics and the math okay so now let's + + + align:start position:0% +graphics and the math okay so now let's +talk about an example of a supply demand + + align:start position:0% +talk about an example of a supply demand + + + align:start position:0% +talk about an example of a supply demand +model and let's focus on the market for + + align:start position:0% +model and let's focus on the market for + + + align:start position:0% +model and let's focus on the market for +roses + + align:start position:0% +roses + + + align:start position:0% +roses +what is a market a Market's what it + + align:start position:0% +what is a market a Market's what it + + + align:start position:0% +what is a market a Market's what it +sounds like it's buyers and sellers + + align:start position:0% +sounds like it's buyers and sellers + + + align:start position:0% +sounds like it's buyers and sellers +coming together are there any more any + + align:start position:0% +coming together are there any more any + + + align:start position:0% +coming together are there any more any +extra handouts around is everyone have + + align:start position:0% +extra handouts around is everyone have + + + align:start position:0% +extra handouts around is everyone have +one everyone have a + + align:start position:0% +one everyone have a + + + align:start position:0% +one everyone have a +handout okay good that's fine then okay + + align:start position:0% +handout okay good that's fine then okay + + + align:start position:0% +handout okay good that's fine then okay +let's talk about the the markets for D + + align:start position:0% +let's talk about the the markets for D + + + align:start position:0% +let's talk about the the markets for D +let's talk about the market for Roses + + align:start position:0% +let's talk about the market for Roses + + + align:start position:0% +let's talk about the market for Roses +okay first of all what is a market a + + align:start position:0% +okay first of all what is a market a + + + align:start position:0% +okay first of all what is a market a +market is think of a market to start + + align:start position:0% +market is think of a market to start + + + align:start position:0% +market is think of a market to start +yeah like another page right the hand + + align:start position:0% +yeah like another page right the hand + + + align:start position:0% +yeah like another page right the hand +has graphs on it does anyone have hand + + align:start position:0% + + + + align:start position:0% + +out did how me you + + align:start position:0% + + + + align:start position:0% + +print what's that is there any is there + + align:start position:0% +print what's that is there any is there + + + align:start position:0% +print what's that is there any is there +an extra pile sitting around there of + + align:start position:0% +an extra pile sitting around there of + + + align:start position:0% +an extra pile sitting around there of +handouts we got some extras there okay + + align:start position:0% +handouts we got some extras there okay + + + align:start position:0% +handouts we got some extras there okay +pass those around make sure you know + + align:start position:0% +pass those around make sure you know + + + align:start position:0% +pass those around make sure you know +pass those around and + + align:start position:0% +pass those around and + + + align:start position:0% +pass those around and +uh yeah next time they'll be in the back + + align:start position:0% +uh yeah next time they'll be in the back + + + align:start position:0% +uh yeah next time they'll be in the back +so please you know raise your hand if + + align:start position:0% +so please you know raise your hand if + + + align:start position:0% +so please you know raise your hand if +you don't have a hand out and let's try + + align:start position:0% +you don't have a hand out and let's try + + + align:start position:0% +you don't have a hand out and let's try +to pass those around okay pedri can you + + align:start position:0% +to pass those around okay pedri can you + + + align:start position:0% +to pass those around okay pedri can you +grab one for me + + align:start position:0% +grab one for me + + + align:start position:0% +grab one for me +um okay so basically let's think about + + align:start position:0% +um okay so basically let's think about + + + align:start position:0% +um okay so basically let's think about +the market for Roses what is a market a + + align:start position:0% +the market for Roses what is a market a + + + align:start position:0% +the market for Roses what is a market a +market is a place where buyers and + + align:start position:0% +market is a place where buyers and + + + align:start position:0% +market is a place where buyers and +sellers come together to make + + align:start position:0% +sellers come together to make + + + align:start position:0% +sellers come together to make +transactions okay think of it like the + + align:start position:0% +transactions okay think of it like the + + + align:start position:0% +transactions okay think of it like the +old timey markets of ancient England + + align:start position:0% +old timey markets of ancient England + + + align:start position:0% +old timey markets of ancient England +were literally the only way to transact + + align:start position:0% +were literally the only way to transact + + + align:start position:0% +were literally the only way to transact +was physically being in the same + + align:start position:0% +was physically being in the same + + + align:start position:0% +was physically being in the same +place where the buyers and sellers would + + align:start position:0% +place where the buyers and sellers would + + + align:start position:0% +place where the buyers and sellers would +come to Market once a week and the + + align:start position:0% +come to Market once a week and the + + + align:start position:0% +come to Market once a week and the +people bring their cows and people who + + align:start position:0% +people bring their cows and people who + + + align:start position:0% +people bring their cows and people who +wanted milk would come in or meat would + + align:start position:0% +wanted milk would come in or meat would + + + align:start position:0% +wanted milk would come in or meat would +come in and they would transact think of + + align:start position:0% +come in and they would transact think of + + + align:start position:0% +come in and they would transact think of +the market that way now of course that's + + align:start position:0% +the market that way now of course that's + + + align:start position:0% +the market that way now of course that's +not how the modern Market works but + + align:start position:0% +not how the modern Market works but + + + align:start position:0% +not how the modern Market works but +that's the way we want you to + + align:start position:0% +that's the way we want you to + + + align:start position:0% +that's the way we want you to +intuitively think of a market it's + + align:start position:0% +intuitively think of a market it's + + + align:start position:0% +intuitively think of a market it's +literally a place where buyers and sells + + align:start position:0% +literally a place where buyers and sells + + + align:start position:0% +literally a place where buyers and sells +are + + align:start position:0% +are + + + align:start position:0% +are +interacting and it turns out that + + align:start position:0% +interacting and it turns out that + + + align:start position:0% +interacting and it turns out that +intuition will work even even given the + + align:start position:0% +intuition will work even even given the + + + align:start position:0% +intuition will work even even given the +modern + + align:start position:0% +modern + + + align:start position:0% +modern +economy okay so now who else doesn't + + align:start position:0% +economy okay so now who else doesn't + + + align:start position:0% +economy okay so now who else doesn't +have handouts everyone got the + + align:start position:0% +have handouts everyone got the + + + align:start position:0% +have handouts everyone got the +graphs okay all right so um now let's + + align:start position:0% +graphs okay all right so um now let's + + + align:start position:0% +graphs okay all right so um now let's +talk about the market for roses in + + align:start position:0% +talk about the market for roses in + + + align:start position:0% +talk about the market for roses in +figure 11 one we have the market for + + align:start position:0% +figure 11 one we have the market for + + + align:start position:0% +figure 11 one we have the market for +Roses okay on the xaxis the horizontal + + align:start position:0% +Roses okay on the xaxis the horizontal + + + align:start position:0% +Roses okay on the xaxis the horizontal +we have the quantity of roses I'm going + + align:start position:0% +we have the quantity of roses I'm going + + + align:start position:0% +we have the quantity of roses I'm going +to by the way try to have handouts for + + align:start position:0% +to by the way try to have handouts for + + + align:start position:0% +to by the way try to have handouts for +all the graphs because my handwriting is + + align:start position:0% +all the graphs because my handwriting is + + + align:start position:0% +all the graphs because my handwriting is +so brutal so uh uh you shouldn't have to + + align:start position:0% +so brutal so uh uh you shouldn't have to + + + align:start position:0% +so brutal so uh uh you shouldn't have to +see hopefully if all goes well the sem + + align:start position:0% +see hopefully if all goes well the sem + + + align:start position:0% +see hopefully if all goes well the sem +you should never see me draw a graph on + + align:start position:0% +you should never see me draw a graph on + + + align:start position:0% +you should never see me draw a graph on +the board um so uh on the x-axis with + + align:start position:0% +the board um so uh on the x-axis with + + + align:start position:0% +the board um so uh on the x-axis with +the quantity of roses on the y axis we + + align:start position:0% +the quantity of roses on the y axis we + + + align:start position:0% +the quantity of roses on the y axis we +have the price of + + align:start position:0% +have the price of + + + align:start position:0% +have the price of +roses okay um the demand curve + + align:start position:0% +roses okay um the demand curve + + + align:start position:0% +roses okay um the demand curve +represents the relationship between + + align:start position:0% +represents the relationship between + + + align:start position:0% +represents the relationship between +price and quantity from the consumer's + + align:start position:0% +price and quantity from the consumer's + + + align:start position:0% +price and quantity from the consumer's +perspective so the domain curve in this + + align:start position:0% +perspective so the domain curve in this + + + align:start position:0% +perspective so the domain curve in this +this case is represented by the + + align:start position:0% +this case is represented by the + + + align:start position:0% +this case is represented by the +equation Q equals + + align:start position:0% +equation Q equals + + + align:start position:0% +equation Q equals +1,800 minus 400 + + align:start position:0% + + + + align:start position:0% + +P okay now you're immediately say well + + align:start position:0% +P okay now you're immediately say well + + + align:start position:0% +P okay now you're immediately say well +what where's 1800 400 come from it + + align:start position:0% +what where's 1800 400 come from it + + + align:start position:0% +what where's 1800 400 come from it +doesn't matter right now that's what + + align:start position:0% +doesn't matter right now that's what + + + align:start position:0% +doesn't matter right now that's what +we're going to teach you in the next few + + align:start position:0% +we're going to teach you in the next few + + + align:start position:0% +we're going to teach you in the next few +lectures right now that's just that's an + + align:start position:0% +lectures right now that's just that's an + + + align:start position:0% +lectures right now that's just that's an +equation that represents a line and it's + + align:start position:0% +equation that represents a line and it's + + + align:start position:0% +equation that represents a line and it's +the critical aspect of that equation is + + align:start position:0% +the critical aspect of that equation is + + + align:start position:0% +the critical aspect of that equation is +that there's a negative + + align:start position:0% +that there's a negative + + + align:start position:0% +that there's a negative +relationship between + + align:start position:0% +relationship between + + + align:start position:0% +relationship between +price and quantity as price goes up + + align:start position:0% +price and quantity as price goes up + + + align:start position:0% +price and quantity as price goes up +consumers want fewer + + align:start position:0% +consumers want fewer + + + align:start position:0% +consumers want fewer +roses why is that well it's just because + + align:start position:0% +roses why is that well it's just because + + + align:start position:0% +roses why is that well it's just because +of opportunity cost the more expensive + + align:start position:0% +of opportunity cost the more expensive + + + align:start position:0% +of opportunity cost the more expensive +is a rose the more you have to give up + + align:start position:0% +is a rose the more you have to give up + + + align:start position:0% +is a rose the more you have to give up +to buy it so its opportunity cost is + + align:start position:0% +to buy it so its opportunity cost is + + + align:start position:0% +to buy it so its opportunity cost is +higher so you want it + + align:start position:0% +higher so you want it + + + align:start position:0% +higher so you want it +less okay so the higher is the price the + + align:start position:0% +less okay so the higher is the price the + + + align:start position:0% +less okay so the higher is the price the +fewer roses you want so we get a + + align:start position:0% +fewer roses you want so we get a + + + align:start position:0% +fewer roses you want so we get a +downward sloping demand curve the blue + + align:start position:0% +downward sloping demand curve the blue + + + align:start position:0% +downward sloping demand curve the blue +line + + align:start position:0% +line + + + align:start position:0% +line +now the supply curve represents the same + + align:start position:0% +now the supply curve represents the same + + + align:start position:0% +now the supply curve represents the same +relationship between price and quantity + + align:start position:0% +relationship between price and quantity + + + align:start position:0% +relationship between price and quantity +but from the supplier's + + align:start position:0% +but from the supplier's + + + align:start position:0% +but from the supplier's +perspective a supply curve in this case + + align:start position:0% +perspective a supply curve in this case + + + align:start position:0% +perspective a supply curve in this case +that we've drawn here has the equation + + align:start position:0% +that we've drawn here has the equation + + + align:start position:0% +that we've drawn here has the equation +Q equals + + align:start position:0% + + + + align:start position:0% + +200p 200p you'll see here there is a + + align:start position:0% +200p 200p you'll see here there is a + + + align:start position:0% +200p 200p you'll see here there is a +positive relationship between price and + + align:start position:0% +positive relationship between price and + + + align:start position:0% +positive relationship between price and +quantity that is supply curve is upward + + align:start position:0% +quantity that is supply curve is upward + + + align:start position:0% +quantity that is supply curve is upward +sloping as price goes up firms will prod + + align:start position:0% +sloping as price goes up firms will prod + + + align:start position:0% +sloping as price goes up firms will prod +firms will produce more roses why once + + align:start position:0% +firms will produce more roses why once + + + align:start position:0% +firms will produce more roses why once +again opportunity + + align:start position:0% +again opportunity + + + align:start position:0% +again opportunity +cost with a low price producing a rose + + align:start position:0% +cost with a low price producing a rose + + + align:start position:0% +cost with a low price producing a rose +means you can't use that farm to produce + + align:start position:0% +means you can't use that farm to produce + + + align:start position:0% +means you can't use that farm to produce +something + + align:start position:0% +something + + + align:start position:0% +something +else if the price of Rose is low you're + + align:start position:0% +else if the price of Rose is low you're + + + align:start position:0% +else if the price of Rose is low you're +going to use the farm for something else + + align:start position:0% +going to use the farm for something else + + + align:start position:0% +going to use the farm for something else +the price of roses is high you will then + + align:start position:0% +the price of roses is high you will then + + + align:start position:0% +the price of roses is high you will then +use that far to produce roses because + + align:start position:0% +use that far to produce roses because + + + align:start position:0% +use that far to produce roses because +that is a better choice than the next + + align:start position:0% +that is a better choice than the next + + + align:start position:0% +that is a better choice than the next +best + + align:start position:0% +best + + + align:start position:0% +best +alternative so once again this concept + + align:start position:0% +alternative so once again this concept + + + align:start position:0% +alternative so once again this concept +of opportunity has already helped + + align:start position:0% +of opportunity has already helped + + + align:start position:0% +of opportunity has already helped +explain the basic model of Economics the + + align:start position:0% +explain the basic model of Economics the + + + align:start position:0% +explain the basic model of Economics the +single most important model of Economics + + align:start position:0% +single most important model of Economics + + + align:start position:0% +single most important model of Economics +is represented in this graph and you can + + align:start position:0% +is represented in this graph and you can + + + align:start position:0% +is represented in this graph and you can +understand it just by the concept of + + align:start position:0% +understand it just by the concept of + + + align:start position:0% +understand it just by the concept of +opportunity cost that is why we are such + + align:start position:0% +opportunity cost that is why we are such + + + align:start position:0% +opportunity cost that is why we are such +a powerful social science that's why all + + align:start position:0% +a powerful social science that's why all + + + align:start position:0% +a powerful social science that's why all +the other social sciences are [ __ ] + + align:start position:0% +the other social sciences are [ __ ] + + + align:start position:0% +the other social sciences are [ __ ] +jealous of us okay because we can use + + align:start position:0% +jealous of us okay because we can use + + + align:start position:0% +jealous of us okay because we can use +Simple tools to explain much to explain + + align:start position:0% +Simple tools to explain much to explain + + + align:start position:0% +Simple tools to explain much to explain +much of the world and here's a perfect + + align:start position:0% +much of the world and here's a perfect + + + align:start position:0% +much of the world and here's a perfect +example okay now we call the point where + + align:start position:0% +example okay now we call the point where + + + align:start position:0% +example okay now we call the point where +those two curves meet the + + align:start position:0% +those two curves meet the + + + align:start position:0% +those two curves meet the +equilibrium the point where supply and + + align:start position:0% +equilibrium the point where supply and + + + align:start position:0% +equilibrium the point where supply and +demand are in agreement is the + + align:start position:0% +demand are in agreement is the + + + align:start position:0% +demand are in agreement is the +equilibrium that is the point at which + + align:start position:0% +equilibrium that is the point at which + + + align:start position:0% +equilibrium that is the point at which +suppliers are willing to sell roses at + + align:start position:0% +suppliers are willing to sell roses at + + + align:start position:0% +suppliers are willing to sell roses at +the same price consumers are willing to + + align:start position:0% +the same price consumers are willing to + + + align:start position:0% +the same price consumers are willing to +pay for them so with 600 roses 600 box + + align:start position:0% +pay for them so with 600 roses 600 box + + + align:start position:0% +pay for them so with 600 roses 600 box +of roses or whatever it is the the + + align:start position:0% +of roses or whatever it is the the + + + align:start position:0% +of roses or whatever it is the the +equilibrium price is $3 well it's a row + + align:start position:0% +equilibrium price is $3 well it's a row + + + align:start position:0% +equilibrium price is $3 well it's a row +so with 600 rows the equili price is $3 + + align:start position:0% +so with 600 rows the equili price is $3 + + + align:start position:0% +so with 600 rows the equili price is $3 +that is both parties are happy in + + align:start position:0% +that is both parties are happy in + + + align:start position:0% +that is both parties are happy in +equilibrium the key point about + + align:start position:0% +equilibrium the key point about + + + align:start position:0% +equilibrium the key point about +equilibrium as the name + + align:start position:0% +equilibrium as the name + + + align:start position:0% +equilibrium as the name +implies as the term equilibrium implies + + align:start position:0% +implies as the term equilibrium implies + + + align:start position:0% +implies as the term equilibrium implies +it's the point where the system has come + + align:start position:0% +it's the point where the system has come + + + align:start position:0% +it's the point where the system has come +to rest where both parties are happy + + align:start position:0% +to rest where both parties are happy + + + align:start position:0% +to rest where both parties are happy +with the outcome both parties are happy + + align:start position:0% +with the outcome both parties are happy + + + align:start position:0% +with the outcome both parties are happy +because it's on the demand and supply + + align:start position:0% +because it's on the demand and supply + + + align:start position:0% +because it's on the demand and supply +curve since it's on the demand curve + + align:start position:0% +curve since it's on the demand curve + + + align:start position:0% +curve since it's on the demand curve +consumers are willing to pay $3 for 600 + + align:start position:0% +consumers are willing to pay $3 for 600 + + + align:start position:0% +consumers are willing to pay $3 for 600 +roses they wouldn't pay $4 600 roses but + + align:start position:0% +roses they wouldn't pay $4 600 roses but + + + align:start position:0% +roses they wouldn't pay $4 600 roses but +they pay three since it's on the supply + + align:start position:0% +they pay three since it's on the supply + + + align:start position:0% +they pay three since it's on the supply +curve suppliers are willing to accept + + align:start position:0% +curve suppliers are willing to accept + + + align:start position:0% +curve suppliers are willing to accept +$3600 roses they wouldn't accept $2600 + + align:start position:0% +$3600 roses they wouldn't accept $2600 + + + align:start position:0% +$3600 roses they wouldn't accept $2600 +roses but they'll accept $3 because it's + + align:start position:0% +roses but they'll accept $3 because it's + + + align:start position:0% +roses but they'll accept $3 because it's +on the Curve + + align:start position:0% +on the Curve + + + align:start position:0% +on the Curve +so basically it's just two equations and + + align:start position:0% +so basically it's just two equations and + + + align:start position:0% +so basically it's just two equations and +two unknowns you set these two things + + align:start position:0% +two unknowns you set these two things + + + align:start position:0% +two unknowns you set these two things +equal to each other and you solve and + + align:start position:0% +equal to each other and you solve and + + + align:start position:0% +equal to each other and you solve and +you get + + align:start position:0% +you get + + + align:start position:0% +you get +qar equals uh qar equals + + align:start position:0% +qar equals uh qar equals + + + align:start position:0% +qar equals uh qar equals +600 and P star equals three just by two + + align:start position:0% +600 and P star equals three just by two + + + align:start position:0% +600 and P star equals three just by two +equations and two unknowns once again + + align:start position:0% +equations and two unknowns once again + + + align:start position:0% +equations and two unknowns once again +why we only have two goods I could have + + align:start position:0% +why we only have two goods I could have + + + align:start position:0% +why we only have two goods I could have +done this in three dimensions the graph + + align:start position:0% +done this in three dimensions the graph + + + align:start position:0% +done this in three dimensions the graph +would have been uglier the math would + + align:start position:0% +would have been uglier the math would + + + align:start position:0% +would have been uglier the math would +have been harder but nothing would have + + align:start position:0% +have been harder but nothing would have + + + align:start position:0% +have been harder but nothing would have +changed yeah + + align:start position:0% + + + + align:start position:0% + +oh that's a great question basically + + align:start position:0% +oh that's a great question basically + + + align:start position:0% +oh that's a great question basically +they + + align:start position:0% +they + + + align:start position:0% +they +are it's a good question we write down + + align:start position:0% +are it's a good question we write down + + + align:start position:0% +are it's a good question we write down +the function are basically invertible + + align:start position:0% +the function are basically invertible + + + align:start position:0% +the function are basically invertible +and we use them both ways is the bottom + + align:start position:0% +and we use them both ways is the bottom + + + align:start position:0% +and we use them both ways is the bottom +line it doesn't we're really writing + + align:start position:0% +line it doesn't we're really writing + + + align:start position:0% +line it doesn't we're really writing +down equili relation between q and P it + + align:start position:0% +down equili relation between q and P it + + + align:start position:0% +down equili relation between q and P it +doesn't really matter what X and Y is + + align:start position:0% +doesn't really matter what X and Y is + + + align:start position:0% +doesn't really matter what X and Y is +we're really just writing down an equili + + align:start position:0% +we're really just writing down an equili + + + align:start position:0% +we're really just writing down an equili +relationship it's just the convention is + + align:start position:0% +relationship it's just the convention is + + + align:start position:0% +relationship it's just the convention is +to put Q on the xaxis even though the + + align:start position:0% +to put Q on the xaxis even though the + + + align:start position:0% +to put Q on the xaxis even though the +con even though the convention will + + align:start position:0% +con even though the convention will + + + align:start position:0% +con even though the convention will +sometimes right toand curs was p on the + + align:start position:0% +sometimes right toand curs was p on the + + + align:start position:0% +sometimes right toand curs was p on the +left hand side the graphic convention + + align:start position:0% +left hand side the graphic convention + + + align:start position:0% +left hand side the graphic convention +will never change but how you write the + + align:start position:0% +will never change but how you write the + + + align:start position:0% +will never change but how you write the +curves might change how we write the + + align:start position:0% +curves might change how we write the + + + align:start position:0% +curves might change how we write the +equations might change + + align:start position:0% +equations might change + + + align:start position:0% +equations might change +yeah use opportunity cost to justify why + + align:start position:0% +yeah use opportunity cost to justify why + + + align:start position:0% +yeah use opportunity cost to justify why +demand down sloping great question okay + + align:start position:0% +demand down sloping great question okay + + + align:start position:0% +demand down sloping great question okay +let's go through it that's exactly kind + + align:start position:0% +let's go through it that's exactly kind + + + align:start position:0% +let's go through it that's exactly kind +of question I want to hear the semester + + align:start position:0% +of question I want to hear the semester + + + align:start position:0% +of question I want to hear the semester +the reason demand is to someone take a + + align:start position:0% +the reason demand is to someone take a + + + align:start position:0% +the reason demand is to someone take a +crack at + + align:start position:0% +crack at + + + align:start position:0% +crack at +it any anyone to explain yeah and speak + + align:start position:0% +it any anyone to explain yeah and speak + + + align:start position:0% +it any anyone to explain yeah and speak +up if the price is higher in order to + + align:start position:0% +up if the price is higher in order to + + + align:start position:0% +up if the price is higher in order to +get that Rose you had to give up more + + align:start position:0% +get that Rose you had to give up more + + + align:start position:0% +get that Rose you had to give up more +because the price represents like your + + align:start position:0% +because the price represents like your + + + align:start position:0% +because the price represents like your +opportunity right PR the opportunity + + align:start position:0% +opportunity right PR the opportunity + + + align:start position:0% +opportunity right PR the opportunity +cost of any good in the free market is + + align:start position:0% +cost of any good in the free market is + + + align:start position:0% +cost of any good in the free market is +its + + align:start position:0% +its + + + align:start position:0% +its +price so as the as the price goes up the + + align:start position:0% +price so as the as the price goes up the + + + align:start position:0% +price so as the as the price goes up the +opportunity cost goes up why because + + align:start position:0% +opportunity cost goes up why because + + + align:start position:0% +opportunity cost goes up why because +there's more other stuff you could have + + align:start position:0% +there's more other stuff you could have + + + align:start position:0% +there's more other stuff you could have +bought so if it's three bucks a row you + + align:start position:0% +bought so if it's three bucks a row you + + + align:start position:0% +bought so if it's three bucks a row you +could have bought you know a slice of + + align:start position:0% +could have bought you know a slice of + + + align:start position:0% +could have bought you know a slice of +pizza and a Coke but if four Buck if + + align:start position:0% +pizza and a Coke but if four Buck if + + + align:start position:0% +pizza and a Coke but if four Buck if +it's if it's four bucks a rose you uh + + align:start position:0% +it's if it's four bucks a rose you uh + + + align:start position:0% +it's if it's four bucks a rose you uh +four bucks a rose you don't have enough + + align:start position:0% +four bucks a rose you don't have enough + + + align:start position:0% +four bucks a rose you don't have enough +money left to buy both the Coke and the + + align:start position:0% +money left to buy both the Coke and the + + + align:start position:0% +money left to buy both the Coke and the +and the slice of pizza so and but that's + + align:start position:0% +and the slice of pizza so and but that's + + + align:start position:0% +and the slice of pizza so and but that's +a great question because that's exactly + + align:start position:0% +a great question because that's exactly + + + align:start position:0% +a great question because that's exactly +where we're going to go next is the next + + align:start position:0% +where we're going to go next is the next + + + align:start position:0% +where we're going to go next is the next +three lectures are going to tell you + + align:start position:0% +three lectures are going to tell you + + + align:start position:0% +three lectures are going to tell you +where this equation comes from we're + + align:start position:0% +where this equation comes from we're + + + align:start position:0% +where this equation comes from we're +going to start with the basic principles + + align:start position:0% +going to start with the basic principles + + + align:start position:0% +going to start with the basic principles +of people's preferences really almost + + align:start position:0% +of people's preferences really almost + + + align:start position:0% +of people's preferences really almost +philosophical and we're going to derive + + align:start position:0% +philosophical and we're going to derive + + + align:start position:0% +philosophical and we're going to derive +this + + align:start position:0% +this + + + align:start position:0% +this +curve then after that the next five + + align:start position:0% +curve then after that the next five + + + align:start position:0% +curve then after that the next five +lectures will be deriving this curve + + align:start position:0% +lectures will be deriving this curve + + + align:start position:0% +lectures will be deriving this curve +we'll start with the basic principles of + + align:start position:0% +we'll start with the basic principles of + + + align:start position:0% +we'll start with the basic principles of +how firms make decisions and we'll + + align:start position:0% +how firms make decisions and we'll + + + align:start position:0% +how firms make decisions and we'll +derive the supply curve + + align:start position:0% + + + + align:start position:0% + +yeah that that + + align:start position:0% + + + + align:start position:0% + +well it depends on on what I've written + + align:start position:0% +well it depends on on what I've written + + + align:start position:0% +well it depends on on what I've written +on the axis you're right this is this is + + align:start position:0% +on the axis you're right this is this is + + + align:start position:0% +on the axis you're right this is this is +confusing pedri should make a note we + + align:start position:0% +confusing pedri should make a note we + + + align:start position:0% +confusing pedri should make a note we +should probably make this clearer next + + align:start position:0% +should probably make this clearer next + + + align:start position:0% +should probably make this clearer next +time we should have called this number + + align:start position:0% +time we should have called this number + + + align:start position:0% +time we should have called this number +of roses or shouldn't have been called + + align:start position:0% +of roses or shouldn't have been called + + + align:start position:0% +of roses or shouldn't have been called +quantity of roses that's a great point + + align:start position:0% +quantity of roses that's a great point + + + align:start position:0% +quantity of roses that's a great point +we should call this number of roses or + + align:start position:0% +we should call this number of roses or + + + align:start position:0% +we should call this number of roses or +boxes of roses but it's per a quantity + + align:start position:0% +boxes of roses but it's per a quantity + + + align:start position:0% +boxes of roses but it's per a quantity +that's specified in the model great + + align:start position:0% +that's specified in the model great + + + align:start position:0% +that's specified in the model great +question thinking with MIT you cannot + + align:start position:0% +question thinking with MIT you cannot + + + align:start position:0% +question thinking with MIT you cannot +get away with with sloppiness here I + + align:start position:0% +get away with with sloppiness here I + + + align:start position:0% +get away with with sloppiness here I +love it Harvard what the hell you write + + align:start position:0% +love it Harvard what the hell you write + + + align:start position:0% +love it Harvard what the hell you write +whatever you want + + align:start position:0% +whatever you want + + + align:start position:0% +whatever you want +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +usually great question in indeed uh this + + align:start position:0% +usually great question in indeed uh this + + + align:start position:0% +usually great question in indeed uh this +is another cheat we'll do which we'll + + align:start position:0% +is another cheat we'll do which we'll + + + align:start position:0% +is another cheat we'll do which we'll +often write down nonlinear + + align:start position:0% +often write down nonlinear + + + align:start position:0% +often write down nonlinear +representations but draw them + + align:start position:0% +representations but draw them + + + align:start position:0% +representations but draw them +linearly um this is a linear + + align:start position:0% +linearly um this is a linear + + + align:start position:0% +linearly um this is a linear +representation but sometimes we'll have + + align:start position:0% +representation but sometimes we'll have + + + align:start position:0% +representation but sometimes we'll have +nonlinear curves and draw them linearly + + align:start position:0% +nonlinear curves and draw them linearly + + + align:start position:0% +nonlinear curves and draw them linearly +when we do think of it as a local + + align:start position:0% +when we do think of it as a local + + + align:start position:0% +when we do think of it as a local +approximation think of the linear piece + + align:start position:0% +approximation think of the linear piece + + + align:start position:0% +approximation think of the linear piece +as the local approximation to the larger + + align:start position:0% + + + + align:start position:0% + +function okay great questions I love it + + align:start position:0% +function okay great questions I love it + + + align:start position:0% +function okay great questions I love it +okay now this raises this model raises a + + align:start position:0% +okay now this raises this model raises a + + + align:start position:0% +okay now this raises this model raises a +very important distinction that we're + + align:start position:0% +very important distinction that we're + + + align:start position:0% +very important distinction that we're +going to focus on the semester it's + + align:start position:0% +going to focus on the semester it's + + + align:start position:0% +going to focus on the semester it's +going to trip you up I guarantee a + + align:start position:0% +going to trip you up I guarantee a + + + align:start position:0% +going to trip you up I guarantee a +number of times so I want you to very + + align:start position:0% +number of times so I want you to very + + + align:start position:0% +number of times so I want you to very +careful thinking about this which is the + + align:start position:0% +careful thinking about this which is the + + + align:start position:0% +careful thinking about this which is the +distinction between + + align:start position:0% +distinction between + + + align:start position:0% +distinction between +positive + + align:start position:0% +positive + + + align:start position:0% +positive +economics and normative + + align:start position:0% + + + + align:start position:0% + +economics positive economics is the + + align:start position:0% +economics positive economics is the + + + align:start position:0% +economics positive economics is the +study of the way things + + align:start position:0% +study of the way things + + + align:start position:0% +study of the way things +are while normative economics is the + + align:start position:0% +are while normative economics is the + + + align:start position:0% +are while normative economics is the +study of the way things should be okay + + align:start position:0% +study of the way things should be okay + + + align:start position:0% +study of the way things should be okay +positive economics study the way things + + align:start position:0% +positive economics study the way things + + + align:start position:0% +positive economics study the way things +are normative economics to study the way + + align:start position:0% +are normative economics to study the way + + + align:start position:0% +are normative economics to study the way +things should be + + align:start position:0% +things should be + + + align:start position:0% +things should be +okay now to consider to understand this + + align:start position:0% +okay now to consider to understand this + + + align:start position:0% +okay now to consider to understand this +let's consider a great example of + + align:start position:0% +let's consider a great example of + + + align:start position:0% +let's consider a great example of +Economics at work which is eBay okay + + align:start position:0% +Economics at work which is eBay okay + + + align:start position:0% +Economics at work which is eBay okay +when eBay came along okay I know it is + + align:start position:0% +when eBay came along okay I know it is + + + align:start position:0% +when eBay came along okay I know it is +older than all of you but it's younger + + align:start position:0% +older than all of you but it's younger + + + align:start position:0% +older than all of you but it's younger +than me when eBay came along economists + + align:start position:0% +than me when eBay came along economists + + + align:start position:0% +than me when eBay came along economists +are very excited because economists love + + align:start position:0% +are very excited because economists love + + + align:start position:0% +are very excited because economists love +auctions auctions are if you will The + + align:start position:0% +auctions auctions are if you will The + + + align:start position:0% +auctions auctions are if you will The +Standard Market that used to exist in + + align:start position:0% +Standard Market that used to exist in + + + align:start position:0% +Standard Market that used to exist in +you know 15th century England okay it's + + align:start position:0% +you know 15th century England okay it's + + + align:start position:0% +you know 15th century England okay it's +literally people beating against each + + align:start position:0% +literally people beating against each + + + align:start position:0% +literally people beating against each +other in a way that reveals who wants + + align:start position:0% +other in a way that reveals who wants + + + align:start position:0% +other in a way that reveals who wants +the good the most and what's wonderful + + align:start position:0% +the good the most and what's wonderful + + + align:start position:0% +the good the most and what's wonderful +about that and we'll come back to this + + align:start position:0% +about that and we'll come back to this + + + align:start position:0% +about that and we'll come back to this +throughout the semester is it has two + + align:start position:0% +throughout the semester is it has two + + + align:start position:0% +throughout the semester is it has two +great features one is it makes sure the + + align:start position:0% +great features one is it makes sure the + + + align:start position:0% +great features one is it makes sure the +right amount gets produced and two is it + + align:start position:0% +right amount gets produced and two is it + + + align:start position:0% +right amount gets produced and two is it +makes sure the people who want it the + + align:start position:0% +makes sure the people who want it the + + + align:start position:0% +makes sure the people who want it the +most get it one beautiful feature of + + align:start position:0% +most get it one beautiful feature of + + + align:start position:0% +most get it one beautiful feature of +free markets is that they don't just get + + align:start position:0% +free markets is that they don't just get + + + align:start position:0% +free markets is that they don't just get +you to the right aggregate quantity they + + align:start position:0% +you to the right aggregate quantity they + + + align:start position:0% +you to the right aggregate quantity they +also get the get the goods in the hands + + align:start position:0% +also get the get the goods in the hands + + + align:start position:0% +also get the get the goods in the hands +of people who are willing to pay the + + align:start position:0% +of people who are willing to pay the + + + align:start position:0% +of people who are willing to pay the +most for them and that's what what eBay + + align:start position:0% +most for them and that's what what eBay + + + align:start position:0% +most for them and that's what what eBay +did now one auction eBay got a lot of + + align:start position:0% +did now one auction eBay got a lot of + + + align:start position:0% +did now one auction eBay got a lot of +example got a lot of attention I'm sorry + + align:start position:0% +example got a lot of attention I'm sorry + + + align:start position:0% +example got a lot of attention I'm sorry +got a lot of attention which is that + + align:start position:0% +got a lot of attention which is that + + + align:start position:0% +got a lot of attention which is that +somebody put their kidney for auction on + + align:start position:0% +somebody put their kidney for auction on + + + align:start position:0% +somebody put their kidney for auction on +eBay they auctioned their kidney they + + align:start position:0% +eBay they auctioned their kidney they + + + align:start position:0% +eBay they auctioned their kidney they +said I'll give you my kidney for let the + + align:start position:0% +said I'll give you my kidney for let the + + + align:start position:0% +said I'll give you my kidney for let the +bidding started + + align:start position:0% +bidding started + + + align:start position:0% +bidding started +$225,000 the bidding got up to $5 + + align:start position:0% +$225,000 the bidding got up to $5 + + + align:start position:0% +$225,000 the bidding got up to $5 +million before eBay shut it down and + + align:start position:0% +million before eBay shut it down and + + + align:start position:0% +million before eBay shut it down and +said no auctioning human body parts on + + align:start position:0% +said no auctioning human body parts on + + + align:start position:0% +said no auctioning human body parts on +eBay + + align:start position:0% +eBay + + + align:start position:0% +eBay +okay now I don't know why they stopped + + align:start position:0% +okay now I don't know why they stopped + + + align:start position:0% +okay now I don't know why they stopped +at five million out earlier but whatever + + align:start position:0% +at five million out earlier but whatever + + + align:start position:0% +at five million out earlier but whatever +okay so we can with this example we can + + align:start position:0% +okay so we can with this example we can + + + align:start position:0% +okay so we can with this example we can +ask both a positive and a normative + + align:start position:0% +ask both a positive and a normative + + + align:start position:0% +ask both a positive and a normative +question the positive question is why + + align:start position:0% +question the positive question is why + + + align:start position:0% +question the positive question is why +did the price get so high + + align:start position:0% +did the price get so high + + + align:start position:0% +did the price get so high +and here we only need AAL to supply + + align:start position:0% +and here we only need AAL to supply + + + align:start position:0% +and here we only need AAL to supply +demand + + align:start position:0% +demand + + + align:start position:0% +demand +model the demand for a kidney is going + + align:start position:0% +model the demand for a kidney is going + + + align:start position:0% +model the demand for a kidney is going +to be pretty high if you need a kidney + + align:start position:0% +to be pretty high if you need a kidney + + + align:start position:0% +to be pretty high if you need a kidney +to live you're going to pay + + align:start position:0% +to live you're going to pay + + + align:start position:0% +to live you're going to pay +approximately everything you have to get + + align:start position:0% +approximately everything you have to get + + + align:start position:0% +approximately everything you have to get +it the supply of kidneys on the free + + align:start position:0% +it the supply of kidneys on the free + + + align:start position:0% +it the supply of kidneys on the free +market is pretty low like that was the + + align:start position:0% +market is pretty low like that was the + + + align:start position:0% +market is pretty low like that was the +only one I know of okay so it's a + + align:start position:0% +only one I know of okay so it's a + + + align:start position:0% +only one I know of okay so it's a +classic case with a very high demand and + + align:start position:0% +classic case with a very high demand and + + + align:start position:0% +classic case with a very high demand and +a very low Supply you're going to get a + + align:start position:0% +a very low Supply you're going to get a + + + align:start position:0% +a very low Supply you're going to get a +very high price and so it's not + + align:start position:0% +very high price and so it's not + + + align:start position:0% +very high price and so it's not +surprising the price went up and + + align:start position:0% +surprising the price went up and + + + align:start position:0% +surprising the price went up and +probably would have gone up further if + + align:start position:0% +probably would have gone up further if + + + align:start position:0% +probably would have gone up further if +eBay hadn't shut it + + align:start position:0% +eBay hadn't shut it + + + align:start position:0% +eBay hadn't shut it +down but but now we come to the + + align:start position:0% +down but but now we come to the + + + align:start position:0% +down but but now we come to the +normative question which is more + + align:start position:0% +normative question which is more + + + align:start position:0% +normative question which is more +interesting and + + align:start position:0% +interesting and + + + align:start position:0% +interesting and +harder which is um should we be allowed + + align:start position:0% +harder which is um should we be allowed + + + align:start position:0% +harder which is um should we be allowed +to sell our bodily organs on eBay okay + + align:start position:0% +to sell our bodily organs on eBay okay + + + align:start position:0% +to sell our bodily organs on eBay okay +you might think that this is a question + + align:start position:0% +you might think that this is a question + + + align:start position:0% +you might think that this is a question +here in philosophy class but + + align:start position:0% +here in philosophy class but + + + align:start position:0% +here in philosophy class but +fundamentally it's an economics + + align:start position:0% +fundamentally it's an economics + + + align:start position:0% +fundamentally it's an economics +question okay many folks die in America + + align:start position:0% +question okay many folks die in America + + + align:start position:0% +question okay many folks die in America +because though because we do not have + + align:start position:0% +because though because we do not have + + + align:start position:0% +because though because we do not have +enough organs to help those with organ + + align:start position:0% +enough organs to help those with organ + + + align:start position:0% +enough organs to help those with organ +failure we we have a limited supply of + + align:start position:0% +failure we we have a limited supply of + + + align:start position:0% +failure we we have a limited supply of +organs I hope you all are organ donors + + align:start position:0% +organs I hope you all are organ donors + + + align:start position:0% +organs I hope you all are organ donors +on your driver to licenses doesn't cost + + align:start position:0% +on your driver to licenses doesn't cost + + + align:start position:0% +on your driver to licenses doesn't cost +you anything you're gone in anyway and + + align:start position:0% +you anything you're gone in anyway and + + + align:start position:0% +you anything you're gone in anyway and +it can save a + + align:start position:0% +it can save a + + + align:start position:0% +it can save a +life um but um many people don't do that + + align:start position:0% +life um but um many people don't do that + + + align:start position:0% +life um but um many people don't do that +and uh even if they did we're just we + + align:start position:0% +and uh even if they did we're just we + + + align:start position:0% +and uh even if they did we're just we +have a higher demand for organs than we + + align:start position:0% +have a higher demand for organs than we + + + align:start position:0% +have a higher demand for organs than we +can fit now if someone who wants an + + align:start position:0% +can fit now if someone who wants an + + + align:start position:0% +can fit now if someone who wants an +organ is wealthy and willing to pay a + + align:start position:0% +organ is wealthy and willing to pay a + + + align:start position:0% +organ is wealthy and willing to pay a +lot of money for + + align:start position:0% +lot of money for + + + align:start position:0% +lot of money for +it and there's someone else who says + + align:start position:0% +it and there's someone else who says + + + align:start position:0% +it and there's someone else who says +look I got two kidneys you can function + + align:start position:0% +look I got two kidneys you can function + + + align:start position:0% +look I got two kidneys you can function +just fine with one the oddy of kidney + + align:start position:0% +just fine with one the oddy of kidney + + + align:start position:0% +just fine with one the oddy of kidney +failure is really low someone says look + + align:start position:0% +failure is really low someone says look + + + align:start position:0% +failure is really low someone says look +I am desperate Straits I can't feed my + + align:start position:0% +I am desperate Straits I can't feed my + + + align:start position:0% +I am desperate Straits I can't feed my +family I can't house my + + align:start position:0% +family I can't house my + + + align:start position:0% +family I can't house my +family I could sell one kidney still + + align:start position:0% +family I could sell one kidney still + + + align:start position:0% +family I could sell one kidney still +function fine and change my life forever + + align:start position:0% +function fine and change my life forever + + + align:start position:0% +function fine and change my life forever +educate my children build a house do the + + align:start position:0% +educate my children build a house do the + + + align:start position:0% +educate my children build a house do the +things I need to do why shouldn't we let + + align:start position:0% +things I need to do why shouldn't we let + + + align:start position:0% +things I need to do why shouldn't we let +that happen so standard economics would + + align:start position:0% +that happen so standard economics would + + + align:start position:0% +that happen so standard economics would +say great let them auction their body + + align:start position:0% +say great let them auction their body + + + align:start position:0% +say great let them auction their body +parts but in fact there's reasons why we + + align:start position:0% +parts but in fact there's reasons why we + + + align:start position:0% +parts but in fact there's reasons why we +don't think many there's many reasons + + align:start position:0% +don't think many there's many reasons + + + align:start position:0% +don't think many there's many reasons +why that may not a good outcome what are + + align:start position:0% +why that may not a good outcome what are + + + align:start position:0% +why that may not a good outcome what are +those what are reasons we might not want + + align:start position:0% +those what are reasons we might not want + + + align:start position:0% +those what are reasons we might not want +to just say sure let a + + align:start position:0% +to just say sure let a + + + align:start position:0% +to just say sure let a +rip what are some reasons yeah go + + align:start position:0% + + + + align:start position:0% + +ahead yeah so there's fundamentally two + + align:start position:0% +ahead yeah so there's fundamentally two + + + align:start position:0% +ahead yeah so there's fundamentally two +kinds of reasons the first kind is what + + align:start position:0% +kinds of reasons the first kind is what + + + align:start position:0% +kinds of reasons the first kind is what +we'll call market + + align:start position:0% + + + + align:start position:0% + +failures market failures are something + + align:start position:0% +failures market failures are something + + + align:start position:0% +failures market failures are something +we're not going to cover for about the + + align:start position:0% +we're not going to cover for about the + + + align:start position:0% +we're not going to cover for about the +first 11 lectures for the first 11 + + align:start position:0% +first 11 lectures for the first 11 + + + align:start position:0% +first 11 lectures for the first 11 +lectures the free market is going to be + + align:start position:0% +lectures the free market is going to be + + + align:start position:0% +lectures the free market is going to be +king let me be very clear with you + + align:start position:0% +king let me be very clear with you + + + align:start position:0% +king let me be very clear with you +economics is fundamentally a right-wing + + align:start position:0% +economics is fundamentally a right-wing + + + align:start position:0% +economics is fundamentally a right-wing +science okay as we'll come clear through + + align:start position:0% +science okay as we'll come clear through + + + align:start position:0% +science okay as we'll come clear through +the semester I'm kind of a leftwing guy + + align:start position:0% +the semester I'm kind of a leftwing guy + + + align:start position:0% +the semester I'm kind of a leftwing guy +but economics is pretty much a + + align:start position:0% +but economics is pretty much a + + + align:start position:0% +but economics is pretty much a +right-wing science in basic economics + + align:start position:0% +right-wing science in basic economics + + + align:start position:0% +right-wing science in basic economics +says the market knows + + align:start position:0% +says the market knows + + + align:start position:0% +says the market knows +best and the and there's only two + + align:start position:0% +best and the and there's only two + + + align:start position:0% +best and the and there's only two +reasons why you should ever interfere + + align:start position:0% +reasons why you should ever interfere + + + align:start position:0% +reasons why you should ever interfere +with with the market and the first is + + align:start position:0% +with with the market and the first is + + + align:start position:0% +with with the market and the first is +because for some reason the Market's not + + align:start position:0% +because for some reason the Market's not + + + align:start position:0% +because for some reason the Market's not +working properly this is an example we + + align:start position:0% +working properly this is an example we + + + align:start position:0% +working properly this is an example we +it would be fine if everyone + + align:start position:0% +it would be fine if everyone + + + align:start position:0% +it would be fine if everyone +knowledgeably went into this + + align:start position:0% +knowledgeably went into this + + + align:start position:0% +knowledgeably went into this +transaction but what if this turns out + + align:start position:0% +transaction but what if this turns out + + + align:start position:0% +transaction but what if this turns out +this can cause people to like force + + align:start position:0% +this can cause people to like force + + + align:start position:0% +this can cause people to like force +force their children to give up their + + align:start position:0% +force their children to give up their + + + align:start position:0% +force their children to give up their +kidney or do things against their will + + align:start position:0% +kidney or do things against their will + + + align:start position:0% +kidney or do things against their will +other criminal activities um what if + + align:start position:0% +other criminal activities um what if + + + align:start position:0% +other criminal activities um what if +people don't really understand how + + align:start position:0% +people don't really understand how + + + align:start position:0% +people don't really understand how +dangerous it is to give your kidney + + align:start position:0% +dangerous it is to give your kidney + + + align:start position:0% +dangerous it is to give your kidney +there's 50,000 Americans every year + + align:start position:0% +there's 50,000 Americans every year + + + align:start position:0% +there's 50,000 Americans every year +there's now currently about 100,000 + + align:start position:0% +there's now currently about 100,000 + + + align:start position:0% +there's now currently about 100,000 +Americans living with hepatitis C which + + align:start position:0% +Americans living with hepatitis C which + + + align:start position:0% +Americans living with hepatitis C which +causes kidney failure he C can live + + align:start position:0% +causes kidney failure he C can live + + + align:start position:0% +causes kidney failure he C can live +dormant for years before you know you + + align:start position:0% +dormant for years before you know you + + + align:start position:0% +dormant for years before you know you +have it what if you give up your kidney + + align:start position:0% +have it what if you give up your kidney + + + align:start position:0% +have it what if you give up your kidney +find hepatitis C then you're dead so + + align:start position:0% +find hepatitis C then you're dead so + + + align:start position:0% +find hepatitis C then you're dead so +there's lots of reasons why I think well + + align:start position:0% +there's lots of reasons why I think well + + + align:start position:0% +there's lots of reasons why I think well +maybe this Market doesn't work quite as + + align:start position:0% +maybe this Market doesn't work quite as + + + align:start position:0% +maybe this Market doesn't work quite as +well as economists say it does people + + align:start position:0% +well as economists say it does people + + + align:start position:0% +well as economists say it does people +might be misinformed people might be F + + align:start position:0% +might be misinformed people might be F + + + align:start position:0% +might be misinformed people might be F +people might be forced to do it what's + + align:start position:0% +people might be forced to do it what's + + + align:start position:0% +people might be forced to do it what's +interesting is the black market is not + + align:start position:0% +interesting is the black market is not + + + align:start position:0% +interesting is the black market is not +necessarily one of those reasons and + + align:start position:0% +necessarily one of those reasons and + + + align:start position:0% +necessarily one of those reasons and +here's why because the black market + + align:start position:0% +here's why because the black market + + + align:start position:0% +here's why because the black market +economists just say is a market let's + + align:start position:0% +economists just say is a market let's + + + align:start position:0% +economists just say is a market let's +say eBay doesn't allow you to sell your + + align:start position:0% +say eBay doesn't allow you to sell your + + + align:start position:0% +say eBay doesn't allow you to sell your +kidneys so you have to sell it on the + + align:start position:0% +kidneys so you have to sell it on the + + + align:start position:0% +kidneys so you have to sell it on the +black market well if there's no other + + align:start position:0% +black market well if there's no other + + + align:start position:0% +black market well if there's no other +market failures that's okay for the same + + align:start position:0% +market failures that's okay for the same + + + align:start position:0% +market failures that's okay for the same +reason economists think it'd be okay to + + align:start position:0% +reason economists think it'd be okay to + + + align:start position:0% +reason economists think it'd be okay to +sell your body parts there's no reason + + align:start position:0% +sell your body parts there's no reason + + + align:start position:0% +sell your body parts there's no reason +why I tell your body parts on a form + + align:start position:0% +why I tell your body parts on a form + + + align:start position:0% +why I tell your body parts on a form +Market informal Market the only reason + + align:start position:0% +Market informal Market the only reason + + + align:start position:0% +Market informal Market the only reason +why it would be bad would that informal + + align:start position:0% +why it would be bad would that informal + + + align:start position:0% +why it would be bad would that informal +Market comes with other unsavory + + align:start position:0% +Market comes with other unsavory + + + align:start position:0% +Market comes with other unsavory +features like forcing people to sell + + align:start position:0% +features like forcing people to sell + + + align:start position:0% +features like forcing people to sell +their body parts or not being informed + + align:start position:0% +their body parts or not being informed + + + align:start position:0% +their body parts or not being informed +that's what it be bad okay what other + + align:start position:0% +that's what it be bad okay what other + + + align:start position:0% +that's what it be bad okay what other +reasons might we care might be worried + + align:start position:0% +reasons might we care might be worried + + + align:start position:0% +reasons might we care might be worried +about people selling the kidneys yeah + + align:start position:0% +about people selling the kidneys yeah + + + align:start position:0% +about people selling the kidneys yeah +why T shouldn't the + + align:start position:0% +why T shouldn't the + + + align:start position:0% +why T shouldn't the +back it would mean that only like really + + align:start position:0% +back it would mean that only like really + + + align:start position:0% +back it would mean that only like really +rich people + + align:start position:0% +rich people + + + align:start position:0% +rich people +great great answers guys the second + + align:start position:0% +great great answers guys the second + + + align:start position:0% +great great answers guys the second +reason we care is what we call Equity or + + align:start position:0% +reason we care is what we call Equity or + + + align:start position:0% +reason we care is what we call Equity or +fairness which is we might not think + + align:start position:0% +fairness which is we might not think + + + align:start position:0% +fairness which is we might not think +it's fair that rich people get to live + + align:start position:0% +it's fair that rich people get to live + + + align:start position:0% +it's fair that rich people get to live +and poor get to live longer and buy the + + align:start position:0% +and poor get to live longer and buy the + + + align:start position:0% +and poor get to live longer and buy the +organs and poor people + + align:start position:0% +organs and poor people + + + align:start position:0% +organs and poor people +don't okay we might think this is that + + align:start position:0% +don't okay we might think this is that + + + align:start position:0% +don't okay we might think this is that +that this is an unfair + + align:start position:0% +that this is an unfair + + + align:start position:0% +that this is an unfair +outcome now this is what's fascinating + + align:start position:0% +outcome now this is what's fascinating + + + align:start position:0% +outcome now this is what's fascinating +about America which is even though we + + align:start position:0% +about America which is even though we + + + align:start position:0% +about America which is even though we +pride ourselves on being the land of the + + align:start position:0% +pride ourselves on being the land of the + + + align:start position:0% +pride ourselves on being the land of the +market economy we also care a lot about + + align:start position:0% +market economy we also care a lot about + + + align:start position:0% +market economy we also care a lot about +fairness as a nation and this is viewed + + align:start position:0% +fairness as a nation and this is viewed + + + align:start position:0% +fairness as a nation and this is viewed +by many as being complately unfair that + + align:start position:0% +by many as being complately unfair that + + + align:start position:0% +by many as being complately unfair that +the Richer you are the more you can just + + align:start position:0% +the Richer you are the more you can just + + + align:start position:0% +the Richer you are the more you can just +buy part body parts off poor + + align:start position:0% +buy part body parts off poor + + + align:start position:0% +buy part body parts off poor +people now here's what's a little bit + + align:start position:0% +people now here's what's a little bit + + + align:start position:0% +people now here's what's a little bit +sad about this class and the sad about + + align:start position:0% +sad about this class and the sad about + + + align:start position:0% +sad about this class and the sad about +the limitation of only having you know + + align:start position:0% +the limitation of only having you know + + + align:start position:0% +the limitation of only having you know +the number of weeks we have which is I'm + + align:start position:0% +the number of weeks we have which is I'm + + + align:start position:0% +the number of weeks we have which is I'm +not going to talk nearly as much about + + align:start position:0% +not going to talk nearly as much about + + + align:start position:0% +not going to talk nearly as much about +Equity as I'd like to 90% of this course + + align:start position:0% +Equity as I'd like to 90% of this course + + + align:start position:0% +Equity as I'd like to 90% of this course +is going to be about efficiency it's + + align:start position:0% +is going to be about efficiency it's + + + align:start position:0% +is going to be about efficiency it's +going to be about does the market work + + align:start position:0% +going to be about does the market work + + + align:start position:0% +going to be about does the market work +does the market deliver the right + + align:start position:0% +does the market deliver the right + + + align:start position:0% +does the market deliver the right +quantity of goods it's not about equity + + align:start position:0% +quantity of goods it's not about equity + + + align:start position:0% +quantity of goods it's not about equity +which is well does that right quantity + + align:start position:0% +which is well does that right quantity + + + align:start position:0% +which is well does that right quantity +end up going end up causing huge + + align:start position:0% +end up going end up causing huge + + + align:start position:0% +end up going end up causing huge +inequality in + + align:start position:0% +inequality in + + + align:start position:0% +inequality in +Society so that is kind of another + + align:start position:0% +Society so that is kind of another + + + align:start position:0% +Society so that is kind of another +reason why we might care okay and we + + align:start position:0% +reason why we might care okay and we + + + align:start position:0% +reason why we might care okay and we +will discuss Equity leing the semester + + align:start position:0% +will discuss Equity leing the semester + + + align:start position:0% +will discuss Equity leing the semester +but unfortunately not to much later all + + align:start position:0% +but unfortunately not to much later all + + + align:start position:0% +but unfortunately not to much later all +right other questions or thoughts about + + align:start position:0% + + + + align:start position:0% + +that okay let me finally talk about one + + align:start position:0% +that okay let me finally talk about one + + + align:start position:0% +that okay let me finally talk about one +last thing which sort of seems like you + + align:start position:0% +last thing which sort of seems like you + + + align:start position:0% +last thing which sort of seems like you +got to talk about in the first lecture + + align:start position:0% +got to talk about in the first lecture + + + align:start position:0% +got to talk about in the first lecture +of of an economics class which is what + + align:start position:0% +of of an economics class which is what + + + align:start position:0% +of of an economics class which is what +about the underlying structure of the + + align:start position:0% +about the underlying structure of the + + + align:start position:0% +about the underlying structure of the +economy how do we think about different + + align:start position:0% +economy how do we think about different + + + align:start position:0% +economy how do we think about different +models of how economies function and the + + align:start position:0% +models of how economies function and the + + + align:start position:0% +models of how economies function and the +fundamental conflict is between a + + align:start position:0% +fundamental conflict is between a + + + align:start position:0% +fundamental conflict is between a +capitalist + + align:start position:0% + + + + align:start position:0% + +model and a command + + align:start position:0% + + + + align:start position:0% + +model the capitalist model in its purest + + align:start position:0% +model the capitalist model in its purest + + + align:start position:0% +model the capitalist model in its purest +form What's called the LA fair or let it + + align:start position:0% +form What's called the LA fair or let it + + + align:start position:0% +form What's called the LA fair or let it +be uh model is one where individuals + + align:start position:0% +be uh model is one where individuals + + + align:start position:0% +be uh model is one where individuals +decide what to produce and consume with + + align:start position:0% +decide what to produce and consume with + + + align:start position:0% +decide what to produce and consume with +no interference it's a purely free + + align:start position:0% +no interference it's a purely free + + + align:start position:0% +no interference it's a purely free +market okay it's the market that sort of + + align:start position:0% +market okay it's the market that sort of + + + align:start position:0% +market okay it's the market that sort of +existed 500 years ago before we had sort + + align:start position:0% +existed 500 years ago before we had sort + + + align:start position:0% +existed 500 years ago before we had sort +of the truth is it never existed there's + + align:start position:0% +of the truth is it never existed there's + + + align:start position:0% +of the truth is it never existed there's +no such thing we will do a lot of + + align:start position:0% +no such thing we will do a lot of + + + align:start position:0% +no such thing we will do a lot of +teaching by Extremes in this course + + align:start position:0% +teaching by Extremes in this course + + + align:start position:0% +teaching by Extremes in this course +we'll talk about extremes it's a great + + align:start position:0% +we'll talk about extremes it's a great + + + align:start position:0% +we'll talk about extremes it's a great +learning device but there's no never + + align:start position:0% +learning device but there's no never + + + align:start position:0% +learning device but there's no never +been such as a purely capitalistic + + align:start position:0% +been such as a purely capitalistic + + + align:start position:0% +been such as a purely capitalistic +economy most economies like the US are + + align:start position:0% +economy most economies like the US are + + + align:start position:0% +economy most economies like the US are +Market driven but government and + + align:start position:0% +Market driven but government and + + + align:start position:0% +Market driven but government and +socially constrained what does that mean + + align:start position:0% +socially constrained what does that mean + + + align:start position:0% +socially constrained what does that mean +that means yes we let GM decide how many + + align:start position:0% +that means yes we let GM decide how many + + + align:start position:0% +that means yes we let GM decide how many +cars to produce but we have standards on + + align:start position:0% +cars to produce but we have standards on + + + align:start position:0% +cars to produce but we have standards on +what emissions those cars can have and + + align:start position:0% +what emissions those cars can have and + + + align:start position:0% +what emissions those cars can have and +how safe they have to be in a purely + + align:start position:0% +how safe they have to be in a purely + + + align:start position:0% +how safe they have to be in a purely +capitalist economy GM could produce the + + align:start position:0% +capitalist economy GM could produce the + + + align:start position:0% +capitalist economy GM could produce the +most dangerous cars they wanted no one + + align:start position:0% +most dangerous cars they wanted no one + + + align:start position:0% +most dangerous cars they wanted no one +would care and they could be smog Laden + + align:start position:0% +would care and they could be smog Laden + + + align:start position:0% +would care and they could be smog Laden +and no one would care obviously we don't + + align:start position:0% +and no one would care obviously we don't + + + align:start position:0% +and no one would care obviously we don't +have that in America we have regulations + + align:start position:0% +have that in America we have regulations + + + align:start position:0% +have that in America we have regulations +we have taxes on gas we have rules on + + align:start position:0% +we have taxes on gas we have rules on + + + align:start position:0% +we have taxes on gas we have rules on +what you can learn and where you can + + align:start position:0% +what you can learn and where you can + + + align:start position:0% +what you can learn and where you can +learn it Etc so we have what we call a + + align:start position:0% +learn it Etc so we have what we call a + + + align:start position:0% +learn it Etc so we have what we call a +sort of constrained capitalist economy + + align:start position:0% +sort of constrained capitalist economy + + + align:start position:0% +sort of constrained capitalist economy +where fundamentally the decisions on + + align:start position:0% +where fundamentally the decisions on + + + align:start position:0% +where fundamentally the decisions on +what to produce and what to consume are + + align:start position:0% +what to produce and what to consume are + + + align:start position:0% +what to produce and what to consume are +made by individuals within a set of + + align:start position:0% +made by individuals within a set of + + + align:start position:0% +made by individuals within a set of +rules set up by the government and some + + align:start position:0% +rules set up by the government and some + + + align:start position:0% +rules set up by the government and some +also set up by social + + align:start position:0% +also set up by social + + + align:start position:0% +also set up by social +norms okay now the opposite extreme is + + align:start position:0% +norms okay now the opposite extreme is + + + align:start position:0% +norms okay now the opposite extreme is +what we call a command economy and we + + align:start position:0% +what we call a command economy and we + + + align:start position:0% +what we call a command economy and we +actually had almost the closest model + + align:start position:0% +actually had almost the closest model + + + align:start position:0% +actually had almost the closest model +that could exist to this which was the + + align:start position:0% +that could exist to this which was the + + + align:start position:0% +that could exist to this which was the +Soviet Union of my youth the Soviet + + align:start position:0% +Soviet Union of my youth the Soviet + + + align:start position:0% +Soviet Union of my youth the Soviet +Union of my youth it's typically + + align:start position:0% +Union of my youth it's typically + + + align:start position:0% +Union of my youth it's typically +associated with Communism although it + + align:start position:0% +associated with Communism although it + + + align:start position:0% +associated with Communism although it +doesn't have to be command economies + + align:start position:0% +doesn't have to be command economies + + + align:start position:0% +doesn't have to be command economies +don't have to be associated with + + align:start position:0% +don't have to be associated with + + + align:start position:0% +don't have to be associated with +Communism Germany in World War II was a + + align:start position:0% +Communism Germany in World War II was a + + + align:start position:0% +Communism Germany in World War II was a +command economy in the service of + + align:start position:0% +command economy in the service of + + + align:start position:0% +command economy in the service of +fascism it's typically associated with + + align:start position:0% +fascism it's typically associated with + + + align:start position:0% +fascism it's typically associated with +Communism is what we call a command + + align:start position:0% +Communism is what we call a command + + + align:start position:0% +Communism is what we call a command +economy in in that extreme the + + align:start position:0% +economy in in that extreme the + + + align:start position:0% +economy in in that extreme the +government makes all production + + align:start position:0% +government makes all production + + + align:start position:0% +government makes all production +allocation decisions people don't decide + + align:start position:0% +allocation decisions people don't decide + + + align:start position:0% +allocation decisions people don't decide +what they get the government decides + + align:start position:0% +what they get the government decides + + + align:start position:0% +what they get the government decides +what they get so it's the other extreme + + align:start position:0% +what they get so it's the other extreme + + + align:start position:0% +what they get so it's the other extreme +there's no free + + align:start position:0% +there's no free + + + align:start position:0% +there's no free +transactions it's the government making + + align:start position:0% +transactions it's the government making + + + align:start position:0% +transactions it's the government making +all the rules not just about how much + + align:start position:0% +all the rules not just about how much + + + align:start position:0% +all the rules not just about how much +should be produced but who gets what's + + align:start position:0% +should be produced but who gets what's + + + align:start position:0% +should be produced but who gets what's +produced okay so in the free market the + + align:start position:0% +produced okay so in the free market the + + + align:start position:0% +produced okay so in the free market the +market subject set of government sort of + + align:start position:0% +market subject set of government sort of + + + align:start position:0% +market subject set of government sort of +you guys have bowled there's like the + + align:start position:0% +you guys have bowled there's like the + + + align:start position:0% +you guys have bowled there's like the +bumpers you can up when you're little + + align:start position:0% +bumpers you can up when you're little + + + align:start position:0% +bumpers you can up when you're little +kid and you bowl and they keep the ball + + align:start position:0% +kid and you bowl and they keep the ball + + + align:start position:0% +kid and you bowl and they keep the ball +on that bowling lane so think of the + + align:start position:0% +on that bowling lane so think of the + + + align:start position:0% +on that bowling lane so think of the +government you know in a capital economy + + align:start position:0% +government you know in a capital economy + + + align:start position:0% +government you know in a capital economy +is those sort of those those those uh + + align:start position:0% +is those sort of those those those uh + + + align:start position:0% +is those sort of those those those uh +guides on the side that help keep the + + align:start position:0% +guides on the side that help keep the + + + align:start position:0% +guides on the side that help keep the +ball in the lane but but you get to + + align:start position:0% +ball in the lane but but you get to + + + align:start position:0% +ball in the lane but but you get to +throw the ball on decide what if you're + + align:start position:0% +throw the ball on decide what if you're + + + align:start position:0% +throw the ball on decide what if you're +going to which pin you're going to go + + align:start position:0% +going to which pin you're going to go + + + align:start position:0% +going to which pin you're going to go +for in in command economy they literally + + align:start position:0% +for in in command economy they literally + + + align:start position:0% +for in in command economy they literally +they tell you go to the end of Lane and + + align:start position:0% +they tell you go to the end of Lane and + + + align:start position:0% +they tell you go to the end of Lane and +knock down pin seven okay uh it's a very + + align:start position:0% +knock down pin seven okay uh it's a very + + + align:start position:0% +knock down pin seven okay uh it's a very +it's a very different + + align:start position:0% +it's a very different + + + align:start position:0% +it's a very different +model now in + + align:start position:0% +model now in + + + align:start position:0% +model now in +theory the argument for the command + + align:start position:0% +theory the argument for the command + + + align:start position:0% +theory the argument for the command +model is that it can ensure that the + + align:start position:0% +model is that it can ensure that the + + + align:start position:0% +model is that it can ensure that the +right Goods get produced and distributed + + align:start position:0% +right Goods get produced and distributed + + + align:start position:0% +right Goods get produced and distributed +as fairly as possible the idea this the + + align:start position:0% +as fairly as possible the idea this the + + + align:start position:0% +as fairly as possible the idea this the +theory is quite simple it goes back to + + align:start position:0% +theory is quite simple it goes back to + + + align:start position:0% +theory is quite simple it goes back to +KL marks the theory makes a lot of sense + + align:start position:0% +KL marks the theory makes a lot of sense + + + align:start position:0% +KL marks the theory makes a lot of sense +which is look the government's job is to + + align:start position:0% +which is look the government's job is to + + + align:start position:0% +which is look the government's job is to +make sure society's as well off as + + align:start position:0% +make sure society's as well off as + + + align:start position:0% +make sure society's as well off as +possible it does that by making sure the + + align:start position:0% +possible it does that by making sure the + + + align:start position:0% +possible it does that by making sure the +right things get produced and get to the + + align:start position:0% +right things get produced and get to the + + + align:start position:0% +right things get produced and get to the +right people and we can't trust the + + align:start position:0% +right people and we can't trust the + + + align:start position:0% +right people and we can't trust the +market to do that only the government + + align:start position:0% +market to do that only the government + + + align:start position:0% +market to do that only the government +can do that okay this is a great + + align:start position:0% +can do that okay this is a great + + + align:start position:0% +can do that okay this is a great +argument in theory in practice it + + align:start position:0% +argument in theory in practice it + + + align:start position:0% +argument in theory in practice it +doesn't work and it doesn't work for two + + align:start position:0% +doesn't work and it doesn't work for two + + + align:start position:0% +doesn't work and it doesn't work for two +reasons it first of all it's just too + + align:start position:0% +reasons it first of all it's just too + + + align:start position:0% +reasons it first of all it's just too +damn hard to make all those + + align:start position:0% +damn hard to make all those + + + align:start position:0% +damn hard to make all those +decisions any government no matter how + + align:start position:0% +decisions any government no matter how + + + align:start position:0% +decisions any government no matter how +large and how benevolent cannot make the + + align:start position:0% +large and how benevolent cannot make the + + + align:start position:0% +large and how benevolent cannot make the +enormous massive quantity of billions + + align:start position:0% +enormous massive quantity of billions + + + align:start position:0% +enormous massive quantity of billions +and billions of decisions that need to + + align:start position:0% +and billions of decisions that need to + + + align:start position:0% +and billions of decisions that need to +be made think about every good we + + align:start position:0% +be made think about every good we + + + align:start position:0% +be made think about every good we +consume in America a government deciding + + align:start position:0% +consume in America a government deciding + + + align:start position:0% +consume in America a government deciding +how much of it to make and literally who + + align:start position:0% +how much of it to make and literally who + + + align:start position:0% +how much of it to make and literally who +gets it okay it's overwhelming + + align:start position:0% +gets it okay it's overwhelming + + + align:start position:0% +gets it okay it's overwhelming +governments can't do it so that led to + + align:start position:0% +governments can't do it so that led to + + + align:start position:0% +governments can't do it so that led to +things like in East Germany I was in + + align:start position:0% +things like in East Germany I was in + + + align:start position:0% +things like in East Germany I was in +East Germany a year ago and I went to + + align:start position:0% +East Germany a year ago and I went to + + + align:start position:0% +East Germany a year ago and I went to +went to the Museum of East Germany and + + align:start position:0% +went to the Museum of East Germany and + + + align:start position:0% +went to the Museum of East Germany and +uh they talk about how in in back in + + align:start position:0% +uh they talk about how in in back in + + + align:start position:0% +uh they talk about how in in back in +communist days in East Germany uh no one + + align:start position:0% +communist days in East Germany uh no one + + + align:start position:0% +communist days in East Germany uh no one +had cars but they had so much bread they + + align:start position:0% +had cars but they had so much bread they + + + align:start position:0% +had cars but they had so much bread they +would feed bread to their pigs for food + + align:start position:0% +would feed bread to their pigs for food + + + align:start position:0% +would feed bread to their pigs for food +okay because the government sort of + + align:start position:0% +okay because the government sort of + + + align:start position:0% +okay because the government sort of +screwed up and decided you know + + align:start position:0% +screwed up and decided you know + + + align:start position:0% +screwed up and decided you know +commanded too many too much bread and + + align:start position:0% +commanded too many too much bread and + + + align:start position:0% +commanded too many too much bread and +too few cars okay that's natural it's + + align:start position:0% +too few cars okay that's natural it's + + + align:start position:0% +too few cars okay that's natural it's +going to happen it's just too hard okay + + align:start position:0% +going to happen it's just too hard okay + + + align:start position:0% +going to happen it's just too hard okay +the second problem is that human nature + + align:start position:0% +the second problem is that human nature + + + align:start position:0% +the second problem is that human nature +being what it is a command economy + + align:start position:0% +being what it is a command economy + + + align:start position:0% +being what it is a command economy +inevita leads to massive corruption + + align:start position:0% +inevita leads to massive corruption + + + align:start position:0% +inevita leads to massive corruption +because when a handful of people are in + + align:start position:0% +because when a handful of people are in + + + align:start position:0% +because when a handful of people are in +charge of deciding everything of course + + align:start position:0% +charge of deciding everything of course + + + align:start position:0% +charge of deciding everything of course +they're going to make their lives the + + align:start position:0% +they're going to make their lives the + + + align:start position:0% +they're going to make their lives the +best + + align:start position:0% +best + + + align:start position:0% +best +first so I'm not saying there's not + + align:start position:0% +first so I'm not saying there's not + + + align:start position:0% +first so I'm not saying there's not +corruption in capitalist economies but + + align:start position:0% +corruption in capitalist economies but + + + align:start position:0% +corruption in capitalist economies but +it's sort of inherent in a command + + align:start position:0% +it's sort of inherent in a command + + + align:start position:0% +it's sort of inherent in a command +economy it's inherent because you're + + align:start position:0% +economy it's inherent because you're + + + align:start position:0% +economy it's inherent because you're +giving a set of people the power to + + align:start position:0% +giving a set of people the power to + + + align:start position:0% +giving a set of people the power to +decide who gets what and it's inevitably + + align:start position:0% +decide who gets what and it's inevitably + + + align:start position:0% +decide who gets what and it's inevitably +in human nature they'll decide to give + + align:start position:0% +in human nature they'll decide to give + + + align:start position:0% +in human nature they'll decide to give +themselves the most and + + align:start position:0% +themselves the most and + + + align:start position:0% +themselves the most and +first so that is why really why the + + align:start position:0% +first so that is why really why the + + + align:start position:0% +first so that is why really why the +Soviet Union collapsed because the + + align:start position:0% +Soviet Union collapsed because the + + + align:start position:0% +Soviet Union collapsed because the +command economy simply couldn't get it + + align:start position:0% +command economy simply couldn't get it + + + align:start position:0% +command economy simply couldn't get it +done and let's be clear it did not + + align:start position:0% +done and let's be clear it did not + + + align:start position:0% +done and let's be clear it did not +appear inevitable in the + + align:start position:0% +appear inevitable in the + + + align:start position:0% +appear inevitable in the +1950s there was huge Envy in the US of + + align:start position:0% +1950s there was huge Envy in the US of + + + align:start position:0% +1950s there was huge Envy in the US of +what the Soviet Union was accomplishing + + align:start position:0% +what the Soviet Union was accomplishing + + + align:start position:0% +what the Soviet Union was accomplishing +they came out of a devastating war and + + align:start position:0% +they came out of a devastating war and + + + align:start position:0% +they came out of a devastating war and +built a manufacturing base that was the + + align:start position:0% +built a manufacturing base that was the + + + align:start position:0% +built a manufacturing base that was the +Envy of the entire world even the US + + align:start position:0% +Envy of the entire world even the US + + + align:start position:0% +Envy of the entire world even the US +almost overnight it was incredible + + align:start position:0% +almost overnight it was incredible + + + align:start position:0% +almost overnight it was incredible +and a lot of people questioned whether + + align:start position:0% +and a lot of people questioned whether + + + align:start position:0% +and a lot of people questioned whether +that might after all not be the right + + align:start position:0% +that might after all not be the right + + + align:start position:0% +that might after all not be the right +model it just it turns out over about 30 + + align:start position:0% +model it just it turns out over about 30 + + + align:start position:0% +model it just it turns out over about 30 +years it fell apart because it just + + align:start position:0% +years it fell apart because it just + + + align:start position:0% +years it fell apart because it just +wasn't + + align:start position:0% +wasn't + + + align:start position:0% +wasn't +sustainable now the alternative of + + align:start position:0% +sustainable now the alternative of + + + align:start position:0% +sustainable now the alternative of +course is the uh US economy the capital + + align:start position:0% +course is the uh US economy the capital + + + align:start position:0% +course is the uh US economy the capital +economy which operates by what the + + align:start position:0% +economy which operates by what the + + + align:start position:0% +economy which operates by what the +famous the father of economics Adam + + align:start position:0% +famous the father of economics Adam + + + align:start position:0% +famous the father of economics Adam +Smith calls the Invisible Hand the + + align:start position:0% +Smith calls the Invisible Hand the + + + align:start position:0% +Smith calls the Invisible Hand the +notion invisible hand is you don't need + + align:start position:0% +notion invisible hand is you don't need + + + align:start position:0% +notion invisible hand is you don't need +a government to make all these decisions + + align:start position:0% +a government to make all these decisions + + + align:start position:0% +a government to make all these decisions +because the market makes it for you the + + align:start position:0% +because the market makes it for you the + + + align:start position:0% +because the market makes it for you the +Invisible Hand of the market decides how + + align:start position:0% +Invisible Hand of the market decides how + + + align:start position:0% +Invisible Hand of the market decides how +much you get produced and who should get + + align:start position:0% +much you get produced and who should get + + + align:start position:0% +much you get produced and who should get +it not through any one person making + + align:start position:0% +it not through any one person making + + + align:start position:0% +it not through any one person making +decisions but just through people coming + + align:start position:0% +decisions but just through people coming + + + align:start position:0% +decisions but just through people coming +together in a market and working + + align:start position:0% +together in a market and working + + + align:start position:0% +together in a market and working +together to make those decisions and + + align:start position:0% +together to make those decisions and + + + align:start position:0% +together to make those decisions and +that's what we'll teach you this + + align:start position:0% +that's what we'll teach you this + + + align:start position:0% +that's what we'll teach you this +semester how the market works and how + + align:start position:0% +semester how the market works and how + + + align:start position:0% +semester how the market works and how +those that invisible hand can lead + + align:start position:0% +those that invisible hand can lead + + + align:start position:0% +those that invisible hand can lead +through the magic of the market to the + + align:start position:0% +through the magic of the market to the + + + align:start position:0% +through the magic of the market to the +right Goods being produced and getting + + align:start position:0% +right Goods being produced and getting + + + align:start position:0% +right Goods being produced and getting +in the hands of the right people okay so + + align:start position:0% +in the hands of the right people okay so + + + align:start position:0% +in the hands of the right people okay so +that's a huge advantage and it's worked + + align:start position:0% +that's a huge advantage and it's worked + + + align:start position:0% +that's a huge advantage and it's worked +America is the richest nation in the + + align:start position:0% +America is the richest nation in the + + + align:start position:0% +America is the richest nation in the +world we've grown rapidly for centuries + + align:start position:0% +world we've grown rapidly for centuries + + + align:start position:0% +world we've grown rapidly for centuries +now um and we are um and and we're very + + align:start position:0% +now um and we are um and and we're very + + + align:start position:0% +now um and we are um and and we're very +successful on the other hand it leads to + + align:start position:0% +successful on the other hand it leads to + + + align:start position:0% +successful on the other hand it leads to +tremendous + + align:start position:0% +tremendous + + + align:start position:0% +tremendous +inequality because the way the right + + align:start position:0% +inequality because the way the right + + + align:start position:0% +inequality because the way the right +person to have the good is the person + + align:start position:0% +person to have the good is the person + + + align:start position:0% +person to have the good is the person +who can pay the most for it right in the + + align:start position:0% +who can pay the most for it right in the + + + align:start position:0% +who can pay the most for it right in the +command economy the right person have + + align:start position:0% +command economy the right person have + + + align:start position:0% +command economy the right person have +the good corruption aside is who needs + + align:start position:0% +the good corruption aside is who needs + + + align:start position:0% +the good corruption aside is who needs +it the + + align:start position:0% +it the + + + align:start position:0% +it the +most we take our kidney example the + + align:start position:0% +most we take our kidney example the + + + align:start position:0% +most we take our kidney example the +command economy would say well let's + + align:start position:0% +command economy would say well let's + + + align:start position:0% +command economy would say well let's +find the person close to death and give + + align:start position:0% +find the person close to death and give + + + align:start position:0% +find the person close to death and give +them the kidney the capital econ say + + align:start position:0% +them the kidney the capital econ say + + + align:start position:0% +them the kidney the capital econ say +let's find the person willing to pay the + + align:start position:0% +let's find the person willing to pay the + + + align:start position:0% +let's find the person willing to pay the +most to give them the kidney well that's + + align:start position:0% +most to give them the kidney well that's + + + align:start position:0% +most to give them the kidney well that's +unfair and that is an inevitable outcome + + align:start position:0% +unfair and that is an inevitable outcome + + + align:start position:0% +unfair and that is an inevitable outcome +of a capitalist economy America is the + + align:start position:0% +of a capitalist economy America is the + + + align:start position:0% +of a capitalist economy America is the +most unequal major nation in the world + + align:start position:0% +most unequal major nation in the world + + + align:start position:0% +most unequal major nation in the world +World our inequality dwarfs what we see + + align:start position:0% +World our inequality dwarfs what we see + + + align:start position:0% +World our inequality dwarfs what we see +in other countries around the world the + + align:start position:0% +in other countries around the world the + + + align:start position:0% +in other countries around the world the +top 1% of Americans control 25% of all + + align:start position:0% +top 1% of Americans control 25% of all + + + align:start position:0% +top 1% of Americans control 25% of all +the income in the US which is which is + + align:start position:0% +the income in the US which is which is + + + align:start position:0% +the income in the US which is which is +at least 5% higher than any other major + + align:start position:0% +at least 5% higher than any other major + + + align:start position:0% +at least 5% higher than any other major +nation in the world okay so we have + + align:start position:0% +nation in the world okay so we have + + + align:start position:0% +nation in the world okay so we have +large inequality because basically the + + align:start position:0% +large inequality because basically the + + + align:start position:0% +large inequality because basically the +Mark it's inevitable in a market that'll + + align:start position:0% +Mark it's inevitable in a market that'll + + + align:start position:0% +Mark it's inevitable in a market that'll +happen because people who want to pay + + align:start position:0% +happen because people who want to pay + + + align:start position:0% +happen because people who want to pay +the most get the + + align:start position:0% +the most get the + + + align:start position:0% +the most get the +stuff okay so that gives you the + + align:start position:0% +stuff okay so that gives you the + + + align:start position:0% +stuff okay so that gives you the +tradeoff the consensus I would say among + + align:start position:0% +tradeoff the consensus I would say among + + + align:start position:0% +tradeoff the consensus I would say among +virtually every Economist is that a + + align:start position:0% +virtually every Economist is that a + + + align:start position:0% +virtually every Economist is that a +command economy is not the way to go the + + align:start position:0% +command economy is not the way to go the + + + align:start position:0% +command economy is not the way to go the +debate is within the capitalist + + align:start position:0% +debate is within the capitalist + + + align:start position:0% +debate is within the capitalist +model how far the government should + + align:start position:0% +model how far the government should + + + align:start position:0% +model how far the government should +intervene if you look at countries like + + align:start position:0% +intervene if you look at countries like + + + align:start position:0% +intervene if you look at countries like +Europe they have a much more intervenous + + align:start position:0% +Europe they have a much more intervenous + + + align:start position:0% +Europe they have a much more intervenous +Economist you'll Europe countries being + + align:start position:0% +Economist you'll Europe countries being + + + align:start position:0% +Economist you'll Europe countries being +called socialist they're not socialist + + align:start position:0% +called socialist they're not socialist + + + align:start position:0% +called socialist they're not socialist +socialist means the government controls + + align:start position:0% +socialist means the government controls + + + align:start position:0% +socialist means the government controls +the industry socialist would be there + + align:start position:0% +the industry socialist would be there + + + align:start position:0% +the industry socialist would be there +still consumers don't going decide what + + align:start position:0% +still consumers don't going decide what + + + align:start position:0% +still consumers don't going decide what +to buy but the government produces + + align:start position:0% +to buy but the government produces + + + align:start position:0% +to buy but the government produces +everything the government runs the banks + + align:start position:0% +everything the government runs the banks + + + align:start position:0% +everything the government runs the banks +the government runs the airplanes the + + align:start position:0% +the government runs the airplanes the + + + align:start position:0% +the government runs the airplanes the +government decides how much steel to + + align:start position:0% +government decides how much steel to + + + align:start position:0% +government decides how much steel to +produce the government so in substance a + + align:start position:0% +produce the government so in substance a + + + align:start position:0% +produce the government so in substance a +socialist is sort of halfway between + + align:start position:0% +socialist is sort of halfway between + + + align:start position:0% +socialist is sort of halfway between +capitalist and command economy where the + + align:start position:0% +capitalist and command economy where the + + + align:start position:0% +capitalist and command economy where the +government does the production but + + align:start position:0% +government does the production but + + + align:start position:0% +government does the production but +Market forces decide the + + align:start position:0% +Market forces decide the + + + align:start position:0% +Market forces decide the +allocation that's not true in any other + + align:start position:0% +allocation that's not true in any other + + + align:start position:0% +allocation that's not true in any other +major country in the world okay these + + align:start position:0% +major country in the world okay these + + + align:start position:0% +major country in the world okay these +countries are all different levels of + + align:start position:0% +countries are all different levels of + + + align:start position:0% +countries are all different levels of +constrained capitalist economies they're + + align:start position:0% +constrained capitalist economies they're + + + align:start position:0% +constrained capitalist economies they're +all different width of those bowling + + align:start position:0% +all different width of those bowling + + + align:start position:0% +all different width of those bowling +alleys okay in Europe and many European + + align:start position:0% +alleys okay in Europe and many European + + + align:start position:0% +alleys okay in Europe and many European +nations they have much more constrained + + align:start position:0% +nations they have much more constrained + + + align:start position:0% +nations they have much more constrained +capitalist economies much higher taxes + + align:start position:0% +capitalist economies much higher taxes + + + align:start position:0% +capitalist economies much higher taxes +much more government prevention also + + align:start position:0% +much more government prevention also + + + align:start position:0% +much more government prevention also +much more equal and we'll be talking + + align:start position:0% +much more equal and we'll be talking + + + align:start position:0% +much more equal and we'll be talking +about this semester and what I focus on + + align:start position:0% +about this semester and what I focus on + + + align:start position:0% +about this semester and what I focus on +much more in my course 1441 is how do we + + align:start position:0% +much more in my course 1441 is how do we + + + align:start position:0% +much more in my course 1441 is how do we +think about those + + align:start position:0% +think about those + + + align:start position:0% +think about those +trade-offs between a Freer economy which + + align:start position:0% +trade-offs between a Freer economy which + + + align:start position:0% +trade-offs between a Freer economy which +is larger but leads to more inequality + + align:start position:0% +is larger but leads to more inequality + + + align:start position:0% +is larger but leads to more inequality +than the US and a less free economy with + + align:start position:0% +than the US and a less free economy with + + + align:start position:0% +than the US and a less free economy with +less + + align:start position:0% +less + + + align:start position:0% +less +inequality okay so to guide you to where + + align:start position:0% +inequality okay so to guide you to where + + + align:start position:0% +inequality okay so to guide you to where +we're going to go I'm really big on sort + + align:start position:0% +we're going to go I'm really big on sort + + + align:start position:0% +we're going to go I'm really big on sort +of making sure you have a big picture of + + align:start position:0% +of making sure you have a big picture of + + + align:start position:0% +of making sure you have a big picture of +where we are in this class and once + + align:start position:0% +where we are in this class and once + + + align:start position:0% +where we are in this class and once +again if you're confused not just about + + align:start position:0% +again if you're confused not just about + + + align:start position:0% +again if you're confused not just about +the little picture but the big picture + + align:start position:0% +the little picture but the big picture + + + align:start position:0% +the little picture but the big picture +let's talk I do urge people come talk to + + align:start position:0% +let's talk I do urge people come talk to + + + align:start position:0% +let's talk I do urge people come talk to +me I generally my rule is if it's like a + + align:start position:0% +me I generally my rule is if it's like a + + + align:start position:0% +me I generally my rule is if it's like a +question about a problem set go see the + + align:start position:0% +question about a problem set go see the + + + align:start position:0% +question about a problem set go see the +Tas if it's a question about like I + + align:start position:0% +Tas if it's a question about like I + + + align:start position:0% +Tas if it's a question about like I +don't understand a concept or I want to + + align:start position:0% +don't understand a concept or I want to + + + align:start position:0% +don't understand a concept or I want to +talk about economics in general or life + + align:start position:0% +talk about economics in general or life + + + align:start position:0% +talk about economics in general or life +in general or music or whatever then + + align:start position:0% +in general or music or whatever then + + + align:start position:0% +in general or music or whatever then +come see me okay and I really do urge + + align:start position:0% +come see me okay and I really do urge + + + align:start position:0% +come see me okay and I really do urge +you folks to come come see me uh now + + align:start position:0% +you folks to come come see me uh now + + + align:start position:0% +you folks to come come see me uh now +that I'm chair going I have to be around + + align:start position:0% +that I'm chair going I have to be around + + + align:start position:0% +that I'm chair going I have to be around +all the time so I'm around plenty of + + align:start position:0% +all the time so I'm around plenty of + + + align:start position:0% +all the time so I'm around plenty of +time please just make an appointment and + + align:start position:0% +time please just make an appointment and + + + align:start position:0% +time please just make an appointment and +come see me so where we're going to go + + align:start position:0% +come see me so where we're going to go + + + align:start position:0% +come see me so where we're going to go +from here what we're going to do like I + + align:start position:0% +from here what we're going to do like I + + + align:start position:0% +from here what we're going to do like I +said is the next few lectures we're + + align:start position:0% +said is the next few lectures we're + + + align:start position:0% +said is the next few lectures we're +going to map out what makes a demand + + align:start position:0% +going to map out what makes a demand + + + align:start position:0% +going to map out what makes a demand +curve then we're going to map out what + + align:start position:0% +curve then we're going to map out what + + + align:start position:0% +curve then we're going to map out what +makes a supply curve then we're going to + + align:start position:0% +makes a supply curve then we're going to + + + align:start position:0% +makes a supply curve then we're going to +put them together and talk about + + align:start position:0% +put them together and talk about + + + align:start position:0% +put them together and talk about +basically in some sense come back to + + align:start position:0% +basically in some sense come back to + + + align:start position:0% +basically in some sense come back to +where we started but now with an + + align:start position:0% +where we started but now with an + + + align:start position:0% +where we started but now with an +understanding of what demand and Supply + + align:start position:0% +understanding of what demand and Supply + + + align:start position:0% +understanding of what demand and Supply +mean and why the equilibrium makes sense + + align:start position:0% +mean and why the equilibrium makes sense + + + align:start position:0% +mean and why the equilibrium makes sense +we'll then talk about we'll then turn to + + align:start position:0% +we'll then talk about we'll then turn to + + + align:start position:0% +we'll then talk about we'll then turn to +normative economics and talk about why + + align:start position:0% +normative economics and talk about why + + + align:start position:0% +normative economics and talk about why +the market equilibrium is really the + + align:start position:0% +the market equilibrium is really the + + + align:start position:0% +the market equilibrium is really the +best + + align:start position:0% +best + + + align:start position:0% +best +outcome we're then going to start to + + align:start position:0% +outcome we're then going to start to + + + align:start position:0% +outcome we're then going to start to +talk about where the standard so it's + + align:start position:0% +talk about where the standard so it's + + + align:start position:0% +talk about where the standard so it's +been about the first I would say half of + + align:start position:0% +been about the first I would say half of + + + align:start position:0% +been about the first I would say half of +the class on the standard economic model + + align:start position:0% +the class on the standard economic model + + + align:start position:0% +the class on the standard economic model +the second half of the class will be + + align:start position:0% +the second half of the class will be + + + align:start position:0% +the second half of the class will be +focused on where the standard model + + align:start position:0% +focused on where the standard model + + + align:start position:0% +focused on where the standard model +breaks down + + align:start position:0% +breaks down + + + align:start position:0% +breaks down +what happens when there's monopolies + + align:start position:0% +what happens when there's monopolies + + + align:start position:0% +what happens when there's monopolies +like Google effectively a monopoly on + + align:start position:0% +like Google effectively a monopoly on + + + align:start position:0% +like Google effectively a monopoly on +search engines what happens when we want + + align:start position:0% +search engines what happens when we want + + + align:start position:0% +search engines what happens when we want +to trade with other countries what + + align:start position:0% +to trade with other countries what + + + align:start position:0% +to trade with other countries what +happens when we have to decide how much + + align:start position:0% +happens when we have to decide how much + + + align:start position:0% +happens when we have to decide how much +to save and how hard to work what + + align:start position:0% +to save and how hard to work what + + + align:start position:0% +to save and how hard to work what +happens when we have to decide um where + + align:start position:0% +happens when we have to decide um where + + + align:start position:0% +happens when we have to decide um where +to invest and what to do about global + + align:start position:0% +to invest and what to do about global + + + align:start position:0% +to invest and what to do about global +warming these are all the questions + + align:start position:0% +warming these are all the questions + + + align:start position:0% +warming these are all the questions +we'll tackle in the second half of the + + align:start position:0% +we'll tackle in the second half of the + + + align:start position:0% +we'll tackle in the second half of the +class okay so let me stop there and I + + align:start position:0% +class okay so let me stop there and I + + + align:start position:0% +class okay so let me stop there and I +hope I'll be seeing you all uh every + + align:start position:0% +hope I'll be seeing you all uh every + + + align:start position:0% +hope I'll be seeing you all uh every +Monday and Wednesday thank you \ No newline at end of file diff --git a/9SaekDRtGFw.txt b/9SaekDRtGFw.txt new file mode 100644 index 0000000000000000000000000000000000000000..ade18b2856452645dbd2e7de7196a853168e3c42 --- /dev/null +++ b/9SaekDRtGFw.txt @@ -0,0 +1,1083 @@ +align:start position:0% + +Video + + align:start position:0% + + + + align:start position:0% + +five, prototype problems, not products. + + align:start position:0% +five, prototype problems, not products. + + + align:start position:0% +five, prototype problems, not products. +No one likes uncertainty. If you're + + align:start position:0% +No one likes uncertainty. If you're + + + align:start position:0% +No one likes uncertainty. If you're +innovating, that's all you have. Think + + align:start position:0% +innovating, that's all you have. Think + + + align:start position:0% +innovating, that's all you have. Think +about it. You're tackling a problem no + + align:start position:0% +about it. You're tackling a problem no + + + align:start position:0% +about it. You're tackling a problem no +one has before. without a ready-made + + align:start position:0% +one has before. without a ready-made + + + align:start position:0% +one has before. without a ready-made +problem statement, with a technology no + + align:start position:0% +problem statement, with a technology no + + + align:start position:0% +problem statement, with a technology no +one has used quite that way before and + + align:start position:0% +one has used quite that way before and + + + align:start position:0% +one has used quite that way before and +you're working off a hunch. Really, all + + align:start position:0% +you're working off a hunch. Really, all + + + align:start position:0% +you're working off a hunch. Really, all +you have is uncertainty. I am using the + + align:start position:0% +you have is uncertainty. I am using the + + + align:start position:0% +you have is uncertainty. I am using the +word hunch because it's the best word in + + align:start position:0% +word hunch because it's the best word in + + + align:start position:0% +word hunch because it's the best word in +the English language to describe the + + align:start position:0% +the English language to describe the + + + align:start position:0% +the English language to describe the +state of your idea at the very start. + + align:start position:0% +state of your idea at the very start. + + + align:start position:0% +state of your idea at the very start. +When you start, that idea isn't really + + align:start position:0% +When you start, that idea isn't really + + + align:start position:0% +When you start, that idea isn't really +fleshed out. At best, it's something + + align:start position:0% +fleshed out. At best, it's something + + + align:start position:0% +fleshed out. At best, it's something +exciting you want to work on, but you + + align:start position:0% +exciting you want to work on, but you + + + align:start position:0% +exciting you want to work on, but you +know you need to flesh it out before you + + align:start position:0% +know you need to flesh it out before you + + + align:start position:0% +know you need to flesh it out before you +can even work on it. And so instead of + + align:start position:0% +can even work on it. And so instead of + + + align:start position:0% +can even work on it. And so instead of +talking about ideas and putting all + + align:start position:0% +talking about ideas and putting all + + + align:start position:0% +talking about ideas and putting all +those attributes and ideas as scalable, + + align:start position:0% +those attributes and ideas as scalable, + + + align:start position:0% +those attributes and ideas as scalable, +disruptive, and what not, I invite you + + align:start position:0% +disruptive, and what not, I invite you + + + align:start position:0% +disruptive, and what not, I invite you +to think of everything you're thinking + + align:start position:0% +to think of everything you're thinking + + + align:start position:0% +to think of everything you're thinking +about at the start as a hunch, something + + align:start position:0% +about at the start as a hunch, something + + + align:start position:0% +about at the start as a hunch, something +that should get you excited for what + + align:start position:0% +that should get you excited for what + + + align:start position:0% +that should get you excited for what +comes next, as opposed to stressed out + + align:start position:0% +comes next, as opposed to stressed out + + + align:start position:0% +comes next, as opposed to stressed out +for how big or disruptive it needs to + + align:start position:0% +for how big or disruptive it needs to + + + align:start position:0% +for how big or disruptive it needs to +be. The only way to move forward is to + + align:start position:0% +be. The only way to move forward is to + + + align:start position:0% +be. The only way to move forward is to +get real. The sooner the better, so you + + align:start position:0% +get real. The sooner the better, so you + + + align:start position:0% +get real. The sooner the better, so you +can get on with the job, which I told + + align:start position:0% +can get on with the job, which I told + + + align:start position:0% +can get on with the job, which I told +you already, is fixing what's wrong + + align:start position:0% +you already, is fixing what's wrong + + + align:start position:0% +you already, is fixing what's wrong +about your idea. You start by + + align:start position:0% +about your idea. You start by + + + align:start position:0% +about your idea. You start by +prototyping the problem. Yes, the + + align:start position:0% +prototyping the problem. Yes, the + + + align:start position:0% +prototyping the problem. Yes, the +problem. You may be tempted to start + + align:start position:0% +problem. You may be tempted to start + + + align:start position:0% +problem. You may be tempted to start +prototyping some product or the pitch. + + align:start position:0% +prototyping some product or the pitch. + + + align:start position:0% +prototyping some product or the pitch. +But if a user, the product and the + + align:start position:0% +But if a user, the product and the + + + align:start position:0% +But if a user, the product and the +solution are known, then someone else + + align:start position:0% +solution are known, then someone else + + + align:start position:0% +solution are known, then someone else +must have worked out the problem for you + + align:start position:0% +must have worked out the problem for you + + + align:start position:0% +must have worked out the problem for you +like in math class. That's how much we + + align:start position:0% +like in math class. That's how much we + + + align:start position:0% +like in math class. That's how much we +dislike uncertainty. This is how it + + align:start position:0% +dislike uncertainty. This is how it + + + align:start position:0% +dislike uncertainty. This is how it +typically goes. You end up taking a + + align:start position:0% +typically goes. You end up taking a + + + align:start position:0% +typically goes. You end up taking a +gamble on the solution you imagined and + + align:start position:0% +gamble on the solution you imagined and + + + align:start position:0% +gamble on the solution you imagined and +stop paying attention to the problem. + + align:start position:0% +stop paying attention to the problem. + + + align:start position:0% +stop paying attention to the problem. +You leave no room for being wrong. And + + align:start position:0% +You leave no room for being wrong. And + + + align:start position:0% +You leave no room for being wrong. And +by the time you discover how you were + + align:start position:0% +by the time you discover how you were + + + align:start position:0% +by the time you discover how you were +wrong, failing is the only viable option + + align:start position:0% +wrong, failing is the only viable option + + + align:start position:0% +wrong, failing is the only viable option +you have left. In 2013, in an interview + + align:start position:0% +you have left. In 2013, in an interview + + + align:start position:0% +you have left. In 2013, in an interview +with National Public Radio, Chris + + align:start position:0% +with National Public Radio, Chris + + + align:start position:0% +with National Public Radio, Chris +Hatfield, the Canadian astronaut, + + align:start position:0% +Hatfield, the Canadian astronaut, + + + align:start position:0% +Hatfield, the Canadian astronaut, +described how astronauts prepare for a + + align:start position:0% +described how astronauts prepare for a + + + align:start position:0% +described how astronauts prepare for a +mission to the space station in a way + + align:start position:0% +mission to the space station in a way + + + align:start position:0% +mission to the space station in a way +that I believe captures the difference + + align:start position:0% +that I believe captures the difference + + + align:start position:0% +that I believe captures the difference +between prototyping a problem and + + align:start position:0% +between prototyping a problem and + + + align:start position:0% +between prototyping a problem and +focusing on the solution. + + align:start position:0% +focusing on the solution. + + + align:start position:0% +focusing on the solution. +Half of the risk of a six-month flight + + align:start position:0% +Half of the risk of a six-month flight + + + align:start position:0% +Half of the risk of a six-month flight +is in the first 9 minutes. So, as a + + align:start position:0% +is in the first 9 minutes. So, as a + + + align:start position:0% +is in the first 9 minutes. So, as a +crew, how do you stay focused and how do + + align:start position:0% +crew, how do you stay focused and how do + + + align:start position:0% +crew, how do you stay focused and how do +you not get u paralyzed by the fear of + + align:start position:0% +you not get u paralyzed by the fear of + + + align:start position:0% +you not get u paralyzed by the fear of +it? And the way we do it is to break + + align:start position:0% +it? And the way we do it is to break + + + align:start position:0% +it? And the way we do it is to break +down what are the risks. And a nice way + + align:start position:0% +down what are the risks. And a nice way + + + align:start position:0% +down what are the risks. And a nice way +to keep reminding yourself is what's the + + align:start position:0% +to keep reminding yourself is what's the + + + align:start position:0% +to keep reminding yourself is what's the +next thing that's going to kill me? And + + align:start position:0% +next thing that's going to kill me? And + + + align:start position:0% +next thing that's going to kill me? And +it might be 5 seconds away. It might be + + align:start position:0% +it might be 5 seconds away. It might be + + + align:start position:0% +it might be 5 seconds away. It might be +an inadvertent engine shutdown or it + + align:start position:0% +an inadvertent engine shutdown or it + + + align:start position:0% +an inadvertent engine shutdown or it +might be uh staging of the solid rockets + + align:start position:0% +might be uh staging of the solid rockets + + + align:start position:0% +might be uh staging of the solid rockets +coming off or it might be you know some + + align:start position:0% +coming off or it might be you know some + + + align:start position:0% +coming off or it might be you know some +transition or or or some some key next + + align:start position:0% +transition or or or some some key next + + + align:start position:0% +transition or or or some some key next +thing. We've already say had one + + align:start position:0% +thing. We've already say had one + + + align:start position:0% +thing. We've already say had one +computer fail and we've had one + + align:start position:0% +computer fail and we've had one + + + align:start position:0% +computer fail and we've had one +hydraulic system fail. So if these three + + align:start position:0% +hydraulic system fail. So if these three + + + align:start position:0% +hydraulic system fail. So if these three +things fail now we're you know we need + + align:start position:0% +things fail now we're you know we need + + + align:start position:0% +things fail now we're you know we need +to react right away or we're done. So we + + align:start position:0% +to react right away or we're done. So we + + + align:start position:0% +to react right away or we're done. So we +don't just live with that though. And + + align:start position:0% +don't just live with that though. And + + + align:start position:0% +don't just live with that though. And +and the thing that is really useful I + + align:start position:0% +and the thing that is really useful I + + + align:start position:0% +and the thing that is really useful I +think out of all this is we dig into it + + align:start position:0% +think out of all this is we dig into it + + + align:start position:0% +think out of all this is we dig into it +so deeply and we look at okay so this + + align:start position:0% +so deeply and we look at okay so this + + + align:start position:0% +so deeply and we look at okay so this +might kill us. This is something that + + align:start position:0% +might kill us. This is something that + + + align:start position:0% +might kill us. This is something that +would normally panic us. Let's get + + align:start position:0% +would normally panic us. Let's get + + + align:start position:0% +would normally panic us. Let's get +ready. Let's think about it and we go + + align:start position:0% +ready. Let's think about it and we go + + + align:start position:0% +ready. Let's think about it and we go +into every excruciating detail of why + + align:start position:0% +into every excruciating detail of why + + + align:start position:0% +into every excruciating detail of why +that might affect what we're doing and + + align:start position:0% +that might affect what we're doing and + + + align:start position:0% +that might affect what we're doing and +what we can do to resolve it and have a + + align:start position:0% +what we can do to resolve it and have a + + + align:start position:0% +what we can do to resolve it and have a +plan and be comfortable with it and + + align:start position:0% +plan and be comfortable with it and + + + align:start position:0% +plan and be comfortable with it and +practice it. In this interview, + + align:start position:0% +practice it. In this interview, + + + align:start position:0% +practice it. In this interview, +astronaut Chris Hatfield is talking + + align:start position:0% +astronaut Chris Hatfield is talking + + + align:start position:0% +astronaut Chris Hatfield is talking +about focusing on the problem. To them, + + align:start position:0% +about focusing on the problem. To them, + + + align:start position:0% +about focusing on the problem. To them, +that's going to the space station and + + align:start position:0% +that's going to the space station and + + + align:start position:0% +that's going to the space station and +making it back to Earth. And the way + + align:start position:0% +making it back to Earth. And the way + + + align:start position:0% +making it back to Earth. And the way +they do it is by discovering what might + + align:start position:0% +they do it is by discovering what might + + + align:start position:0% +they do it is by discovering what might +go wrong and finding ways to fix it in + + align:start position:0% +go wrong and finding ways to fix it in + + + align:start position:0% +go wrong and finding ways to fix it in +the rocket, through practice, or + + align:start position:0% +the rocket, through practice, or + + + align:start position:0% +the rocket, through practice, or +whatever. When the mission starts, they + + align:start position:0% +whatever. When the mission starts, they + + + align:start position:0% +whatever. When the mission starts, they +are prepared for everything they + + align:start position:0% +are prepared for everything they + + + align:start position:0% +are prepared for everything they +foresaw, and they're ready to handle + + align:start position:0% +foresaw, and they're ready to handle + + + align:start position:0% +foresaw, and they're ready to handle +many things they could not have + + align:start position:0% +many things they could not have + + + align:start position:0% +many things they could not have +predicted. + + align:start position:0% +predicted. + + + align:start position:0% +predicted. +That is what I mean by prototyping the + + align:start position:0% +That is what I mean by prototyping the + + + align:start position:0% +That is what I mean by prototyping the +problem. + + align:start position:0% +problem. + + + align:start position:0% +problem. +When you prototype the problem, your + + align:start position:0% +When you prototype the problem, your + + + align:start position:0% +When you prototype the problem, your +goal is to make the problem tangible + + align:start position:0% +goal is to make the problem tangible + + + align:start position:0% +goal is to make the problem tangible +enough for you and others. The more + + align:start position:0% +enough for you and others. The more + + + align:start position:0% +enough for you and others. The more +tangible your description of the + + align:start position:0% +tangible your description of the + + + align:start position:0% +tangible your description of the +problem, the easier it will be for you + + align:start position:0% +problem, the easier it will be for you + + + align:start position:0% +problem, the easier it will be for you +and them to see ways to solve the + + align:start position:0% +and them to see ways to solve the + + + align:start position:0% +and them to see ways to solve the +problem. In contrast, prototyping a + + align:start position:0% +problem. In contrast, prototyping a + + + align:start position:0% +problem. In contrast, prototyping a +madeup solution for a problem you do not + + align:start position:0% +madeup solution for a problem you do not + + + align:start position:0% +madeup solution for a problem you do not +understand is like putting the carriage + + align:start position:0% +understand is like putting the carriage + + + align:start position:0% +understand is like putting the carriage +before the horse. You do not want to + + align:start position:0% +before the horse. You do not want to + + + align:start position:0% +before the horse. You do not want to +wait until launch day to see if you're + + align:start position:0% +wait until launch day to see if you're + + + align:start position:0% +wait until launch day to see if you're +working on the problem. If you do, + + align:start position:0% +working on the problem. If you do, + + + align:start position:0% +working on the problem. If you do, +you'll miss out on everything that's not + + align:start position:0% +you'll miss out on everything that's not + + + align:start position:0% +you'll miss out on everything that's not +captured by what you imagined to be the + + align:start position:0% +captured by what you imagined to be the + + + align:start position:0% +captured by what you imagined to be the +solution. It would be as if the + + align:start position:0% +solution. It would be as if the + + + align:start position:0% +solution. It would be as if the +astronauts had picked ahead of time the + + align:start position:0% +astronauts had picked ahead of time the + + + align:start position:0% +astronauts had picked ahead of time the +one thing that might go wrong and + + align:start position:0% +one thing that might go wrong and + + + align:start position:0% +one thing that might go wrong and +prepared only for that. There's more I + + align:start position:0% +prepared only for that. There's more I + + + align:start position:0% +prepared only for that. There's more I +would like to tell you about how to + + align:start position:0% +would like to tell you about how to + + + align:start position:0% +would like to tell you about how to +prototype the problem. I am also aware + + align:start position:0% +prototype the problem. I am also aware + + + align:start position:0% +prototype the problem. I am also aware +old habits die hard. You can find out + + align:start position:0% +old habits die hard. You can find out + + + align:start position:0% +old habits die hard. You can find out +about more strategies in my book, + + align:start position:0% +about more strategies in my book, + + + align:start position:0% +about more strategies in my book, +Innovating Adors Manifesto or in the + + align:start position:0% +Innovating Adors Manifesto or in the + + + align:start position:0% +Innovating Adors Manifesto or in the +many materials I've shared online. For + + align:start position:0% +many materials I've shared online. For + + + align:start position:0% +many materials I've shared online. For +now, let me just give you a tip for how + + align:start position:0% +now, let me just give you a tip for how + + + align:start position:0% +now, let me just give you a tip for how +to get started. This is how you can + + align:start position:0% +to get started. This is how you can + + + align:start position:0% +to get started. This is how you can +start practicing. + + align:start position:0% +start practicing. + + + align:start position:0% +start practicing. +Come up with three solutions to the + + align:start position:0% +Come up with three solutions to the + + + align:start position:0% +Come up with three solutions to the +problem. + + align:start position:0% +problem. + + + align:start position:0% +problem. +Prototype all three. Then ask yourself + + align:start position:0% +Prototype all three. Then ask yourself + + + align:start position:0% +Prototype all three. Then ask yourself +or someone else the following two + + align:start position:0% +or someone else the following two + + + align:start position:0% +or someone else the following two +questions. Are these three solutions + + align:start position:0% +questions. Are these three solutions + + + align:start position:0% +questions. Are these three solutions +sufficiently different? And how would + + align:start position:0% +sufficiently different? And how would + + + align:start position:0% +sufficiently different? And how would +you know either of them actually solves + + align:start position:0% +you know either of them actually solves + + + align:start position:0% +you know either of them actually solves +the problem? + + align:start position:0% +the problem? + + + align:start position:0% +the problem? +Once you start getting real, you realize + + align:start position:0% +Once you start getting real, you realize + + + align:start position:0% +Once you start getting real, you realize +there's multiple ways to chip at the + + align:start position:0% +there's multiple ways to chip at the + + + align:start position:0% +there's multiple ways to chip at the +problem and have an impact. + + align:start position:0% +problem and have an impact. + + + align:start position:0% +problem and have an impact. +[Music] \ No newline at end of file diff --git a/9hdNPVEQLFE.txt b/9hdNPVEQLFE.txt new file mode 100644 index 0000000000000000000000000000000000000000..38b6425824cbffd0dc264a7d9b4e7a43da36e9ea --- /dev/null +++ b/9hdNPVEQLFE.txt @@ -0,0 +1,2659 @@ +align:start position:0% + +so now let me make + + align:start position:0% +so now let me make + + + align:start position:0% +so now let me make +the first of our technical assigns which + + align:start position:0% +the first of our technical assigns which + + + align:start position:0% +the first of our technical assigns which +you can skip over + + align:start position:0% +you can skip over + + + align:start position:0% +you can skip over +if you're not interested in the + + align:start position:0% +if you're not interested in the + + + align:start position:0% +if you're not interested in the +mathematical details but for those of + + align:start position:0% +mathematical details but for those of + + + align:start position:0% +mathematical details but for those of +you that have + + align:start position:0% +you that have + + + align:start position:0% +you that have +a higher level say upper level + + align:start position:0% +a higher level say upper level + + + align:start position:0% +a higher level say upper level +undergraduate + + align:start position:0% +undergraduate + + + align:start position:0% +undergraduate +or even graduate level understanding of + + align:start position:0% +or even graduate level understanding of + + + align:start position:0% +or even graduate level understanding of +transport phenomena fluid mechanics + + align:start position:0% +transport phenomena fluid mechanics + + + align:start position:0% +transport phenomena fluid mechanics +i'd like to show you some of the + + align:start position:0% +i'd like to show you some of the + + + align:start position:0% +i'd like to show you some of the +equations that are behind + + align:start position:0% +equations that are behind + + + align:start position:0% +equations that are behind +the results that i've been quoting in in + + align:start position:0% +the results that i've been quoting in in + + + align:start position:0% +the results that i've been quoting in in +all of the lectures + + align:start position:0% +all of the lectures + + + align:start position:0% +all of the lectures +so in particular let's derive the wells + + align:start position:0% +so in particular let's derive the wells + + + align:start position:0% +so in particular let's derive the wells +curve + + align:start position:0% +curve + + + align:start position:0% +curve +so part of that was + + align:start position:0% +so part of that was + + + align:start position:0% +so part of that was +a theory of drop settling + + align:start position:0% +a theory of drop settling + + + align:start position:0% +a theory of drop settling +here i will quote a certain result + + align:start position:0% +here i will quote a certain result + + + align:start position:0% +here i will quote a certain result +because the derivation would be + + align:start position:0% +because the derivation would be + + + align:start position:0% +because the derivation would be +a lot longer actually for that you could + + align:start position:0% +a lot longer actually for that you could + + + align:start position:0% +a lot longer actually for that you could +refer to my online class 1050x + + align:start position:0% +refer to my online class 1050x + + + align:start position:0% +refer to my online class 1050x +which is that if you have a drop blood + + align:start position:0% +which is that if you have a drop blood + + + align:start position:0% +which is that if you have a drop blood +or a particle + + align:start position:0% +or a particle + + + align:start position:0% +or a particle +of a radius r and it + + align:start position:0% +of a radius r and it + + + align:start position:0% +of a radius r and it +is settling under gravity + + align:start position:0% +is settling under gravity + + + align:start position:0% +is settling under gravity +so it has a mass m and the gravitational + + align:start position:0% +so it has a mass m and the gravitational + + + align:start position:0% +so it has a mass m and the gravitational +force is mg where g is the gravitational + + align:start position:0% +force is mg where g is the gravitational + + + align:start position:0% +force is mg where g is the gravitational +acceleration + + align:start position:0% +acceleration + + + align:start position:0% +acceleration +then there is a flow + + align:start position:0% +then there is a flow + + + align:start position:0% +then there is a flow +of fluid around this object and relative + + align:start position:0% +of fluid around this object and relative + + + align:start position:0% +of fluid around this object and relative +to the moving object the flow is going + + align:start position:0% +to the moving object the flow is going + + + align:start position:0% +to the moving object the flow is going +the other way + + align:start position:0% +the other way + + + align:start position:0% +the other way +and if you solve for the viscous flow + + align:start position:0% +and if you solve for the viscous flow + + + align:start position:0% +and if you solve for the viscous flow +around an object being dragged through a + + align:start position:0% +around an object being dragged through a + + + align:start position:0% +around an object being dragged through a +fluid + + align:start position:0% +fluid + + + align:start position:0% +fluid +then you arrive at the result of stokes + + align:start position:0% +then you arrive at the result of stokes + + + align:start position:0% +then you arrive at the result of stokes +which is the drag on that fluid so if + + align:start position:0% +which is the drag on that fluid so if + + + align:start position:0% +which is the drag on that fluid so if +you're falling at a velocity v + + align:start position:0% +you're falling at a velocity v + + + align:start position:0% +you're falling at a velocity v +then the drag force + + align:start position:0% + + + + align:start position:0% + +is fd + + align:start position:0% +is fd + + + align:start position:0% +is fd +is 6 pi times the radius of the drop + + align:start position:0% +is 6 pi times the radius of the drop + + + align:start position:0% +is 6 pi times the radius of the drop +times the viscosity of the fluid + + align:start position:0% +times the viscosity of the fluid + + + align:start position:0% +times the viscosity of the fluid +times the velocity of the drop so we're + + align:start position:0% +times the velocity of the drop so we're + + + align:start position:0% +times the velocity of the drop so we're +falling at a velocity v + + align:start position:0% +falling at a velocity v + + + align:start position:0% +falling at a velocity v +which is the settling velocity and this + + align:start position:0% +which is the settling velocity and this + + + align:start position:0% +which is the settling velocity and this +here is the stokes drag coefficient + + align:start position:0% +here is the stokes drag coefficient + + + align:start position:0% +here is the stokes drag coefficient +which comes from + + align:start position:0% +which comes from + + + align:start position:0% +which comes from +solving the fluid mechanics of viscous + + align:start position:0% +solving the fluid mechanics of viscous + + + align:start position:0% +solving the fluid mechanics of viscous +flow around a sphere + + align:start position:0% +flow around a sphere + + + align:start position:0% +flow around a sphere +translating at a constant speed we can + + align:start position:0% +translating at a constant speed we can + + + align:start position:0% +translating at a constant speed we can +furthermore + + align:start position:0% +furthermore + + + align:start position:0% +furthermore +say that the the + + align:start position:0% +say that the the + + + align:start position:0% +say that the the +mass of the droplet of course + + align:start position:0% +mass of the droplet of course + + + align:start position:0% +mass of the droplet of course +is 4 pi over 3 + + align:start position:0% +is 4 pi over 3 + + + align:start position:0% +is 4 pi over 3 +times the density of the droplet liquid + + align:start position:0% +times the density of the droplet liquid + + + align:start position:0% +times the density of the droplet liquid +times the radius cubed and so given the + + align:start position:0% +times the radius cubed and so given the + + + align:start position:0% +times the radius cubed and so given the +mass of the droplet + + align:start position:0% +mass of the droplet + + + align:start position:0% +mass of the droplet +there's a force balance between the + + align:start position:0% +there's a force balance between the + + + align:start position:0% +there's a force balance between the +gravitational force + + align:start position:0% +gravitational force + + + align:start position:0% +gravitational force +mg and the drag force when the particle + + align:start position:0% +mg and the drag force when the particle + + + align:start position:0% +mg and the drag force when the particle +reaches a terminal velocity so if we + + align:start position:0% +reaches a terminal velocity so if we + + + align:start position:0% +reaches a terminal velocity so if we +think of this vs as the terminal + + align:start position:0% +think of this vs as the terminal + + + align:start position:0% +think of this vs as the terminal +velocity where it's accelerated until + + align:start position:0% +velocity where it's accelerated until + + + align:start position:0% +velocity where it's accelerated until +there's a balance between the forces and + + align:start position:0% +there's a balance between the forces and + + + align:start position:0% +there's a balance between the forces and +is moving at a constant speed + + align:start position:0% +is moving at a constant speed + + + align:start position:0% +is moving at a constant speed +it's given by this force balance and + + align:start position:0% +it's given by this force balance and + + + align:start position:0% +it's given by this force balance and +from that equation we can solve for the + + align:start position:0% +from that equation we can solve for the + + + align:start position:0% +from that equation we can solve for the +settling velocity which + + align:start position:0% +settling velocity which + + + align:start position:0% +settling velocity which +is mg divided by 6 pi + + align:start position:0% +is mg divided by 6 pi + + + align:start position:0% +is mg divided by 6 pi +r and i'll out to use the same notation + + align:start position:0% +r and i'll out to use the same notation + + + align:start position:0% +r and i'll out to use the same notation +before i'll call this mu a of the air + + align:start position:0% +before i'll call this mu a of the air + + + align:start position:0% +before i'll call this mu a of the air +but generally it's the viscosity of the + + align:start position:0% +but generally it's the viscosity of the + + + align:start position:0% +but generally it's the viscosity of the +ambient fluid around the particle as + + align:start position:0% +ambient fluid around the particle as + + + align:start position:0% +ambient fluid around the particle as +it's settling + + align:start position:0% +it's settling + + + align:start position:0% +it's settling +and if we plug in uh the value for mg so + + align:start position:0% +and if we plug in uh the value for mg so + + + align:start position:0% +and if we plug in uh the value for mg so +that's + + align:start position:0% +that's + + + align:start position:0% +that's +four thirds pi + + align:start position:0% + + + + align:start position:0% + +rho g r cubed over six + + align:start position:0% +rho g r cubed over six + + + align:start position:0% +rho g r cubed over six +pi r rho a and so if we simplify that + + align:start position:0% +pi r rho a and so if we simplify that + + + align:start position:0% +pi r rho a and so if we simplify that +we end up with 2 9 + + align:start position:0% +we end up with 2 9 + + + align:start position:0% +we end up with 2 9 +rho g r squared + + align:start position:0% +rho g r squared + + + align:start position:0% +rho g r squared +divided by mu a so that's the settling + + align:start position:0% +divided by mu a so that's the settling + + + align:start position:0% +divided by mu a so that's the settling +speed + + align:start position:0% +speed + + + align:start position:0% +speed +and this is a pretty important concept + + align:start position:0% +and this is a pretty important concept + + + align:start position:0% +and this is a pretty important concept +so i'll just sketch it + + align:start position:0% +so i'll just sketch it + + + align:start position:0% +so i'll just sketch it +here so if we want to know what's the + + align:start position:0% +here so if we want to know what's the + + + align:start position:0% +here so if we want to know what's the +settling speed as a function of the + + align:start position:0% +settling speed as a function of the + + + align:start position:0% +settling speed as a function of the +radius of the + + align:start position:0% +radius of the + + + align:start position:0% +radius of the +of the drop then you see it grows like r + + align:start position:0% +of the drop then you see it grows like r + + + align:start position:0% +of the drop then you see it grows like r +squared so it's like this + + align:start position:0% + + + + align:start position:0% + +and then to put a scale on that um if we + + align:start position:0% +and then to put a scale on that um if we + + + align:start position:0% +and then to put a scale on that um if we +have a particle that is three microns + + align:start position:0% +have a particle that is three microns + + + align:start position:0% +have a particle that is three microns +so that's really an aerosol particle + + align:start position:0% +so that's really an aerosol particle + + + align:start position:0% +so that's really an aerosol particle +then the settling speed is around one + + align:start position:0% +then the settling speed is around one + + + align:start position:0% +then the settling speed is around one +millimeter a second if we use + + align:start position:0% +millimeter a second if we use + + + align:start position:0% +millimeter a second if we use +the density of water and the viscosity + + align:start position:0% +the density of water and the viscosity + + + align:start position:0% +the density of water and the viscosity +of air + + align:start position:0% +of air + + + align:start position:0% +of air +for this formula and so that's already a + + align:start position:0% +for this formula and so that's already a + + + align:start position:0% +for this formula and so that's already a +fairly slow settling speed millimeter + + align:start position:0% +fairly slow settling speed millimeter + + + align:start position:0% +fairly slow settling speed millimeter +per second so you can already see the + + align:start position:0% +per second so you can already see the + + + align:start position:0% +per second so you can already see the +particles that are in the micro range + + align:start position:0% +particles that are in the micro range + + + align:start position:0% +particles that are in the micro range +will be suspended in the air for a long + + align:start position:0% +will be suspended in the air for a long + + + align:start position:0% +will be suspended in the air for a long +period of time as long as they don't + + align:start position:0% +period of time as long as they don't + + + align:start position:0% +period of time as long as they don't +evaporate away + + align:start position:0% +evaporate away + + + align:start position:0% +evaporate away +and so that is now the second part of + + align:start position:0% +and so that is now the second part of + + + align:start position:0% +and so that is now the second part of +the calculation + + align:start position:0% +the calculation + + + align:start position:0% +the calculation +oh and actually to finish the first part + + align:start position:0% +oh and actually to finish the first part + + + align:start position:0% +oh and actually to finish the first part +here what we're left with + + align:start position:0% +here what we're left with + + + align:start position:0% +here what we're left with +is that the settling time is + + align:start position:0% +is that the settling time is + + + align:start position:0% +is that the settling time is +l over v s and that's the formula that + + align:start position:0% +l over v s and that's the formula that + + + align:start position:0% +l over v s and that's the formula that +we had + + align:start position:0% +we had + + + align:start position:0% +we had +before which is 9 mu + + align:start position:0% +before which is 9 mu + + + align:start position:0% +before which is 9 mu +a l divided by 2 rho g + + align:start position:0% +a l divided by 2 rho g + + + align:start position:0% +a l divided by 2 rho g +r squared okay so this is our + + align:start position:0% +r squared okay so this is our + + + align:start position:0% +r squared okay so this is our +first part of the wells curve so if i + + align:start position:0% +first part of the wells curve so if i + + + align:start position:0% +first part of the wells curve so if i +draw + + align:start position:0% +draw + + + align:start position:0% +draw +the wells curve over here in the + + align:start position:0% +the wells curve over here in the + + + align:start position:0% +the wells curve over here in the +traditional way + + align:start position:0% +traditional way + + + align:start position:0% +traditional way +where i plot on the horizontal axis the + + align:start position:0% +where i plot on the horizontal axis the + + + align:start position:0% +where i plot on the horizontal axis the +size of the particle and in a downward + + align:start position:0% +size of the particle and in a downward + + + align:start position:0% +size of the particle and in a downward +axis + + align:start position:0% +axis + + + align:start position:0% +axis +we draw the time then we have a curve + + align:start position:0% +we draw the time then we have a curve + + + align:start position:0% +we draw the time then we have a curve +like this + + align:start position:0% +like this + + + align:start position:0% +like this +for settling which and the reason it's + + align:start position:0% +for settling which and the reason it's + + + align:start position:0% +for settling which and the reason it's +drawn down i guess maybe the feeling + + align:start position:0% +drawn down i guess maybe the feeling + + + align:start position:0% +drawn down i guess maybe the feeling +that as you're sort of falling down a + + align:start position:0% +that as you're sort of falling down a + + + align:start position:0% +that as you're sort of falling down a +particle a certain size you hit this + + align:start position:0% +particle a certain size you hit this + + + align:start position:0% +particle a certain size you hit this +curve and that's when you've settled + + align:start position:0% +curve and that's when you've settled + + + align:start position:0% +curve and that's when you've settled +a distance l and fallen out of the air + + align:start position:0% +a distance l and fallen out of the air + + + align:start position:0% +a distance l and fallen out of the air +so now let's look at evaporation + + align:start position:0% +so now let's look at evaporation + + + align:start position:0% +so now let's look at evaporation +which is our second topic um i've lost + + align:start position:0% +which is our second topic um i've lost + + + align:start position:0% +which is our second topic um i've lost +my blue here it is okay + + align:start position:0% +my blue here it is okay + + + align:start position:0% +my blue here it is okay +so + + align:start position:0% + + + + align:start position:0% + +so these droplets are getting very small + + align:start position:0% +so these droplets are getting very small + + + align:start position:0% +so these droplets are getting very small +as they're evaporating and it's + + align:start position:0% +as they're evaporating and it's + + + align:start position:0% +as they're evaporating and it's +happening very quickly + + align:start position:0% +happening very quickly + + + align:start position:0% +happening very quickly +as we shall show in a moment and so a + + align:start position:0% +as we shall show in a moment and so a + + + align:start position:0% +as we shall show in a moment and so a +natural assumption + + align:start position:0% +natural assumption + + + align:start position:0% +natural assumption +is that the uh process is + + align:start position:0% +is that the uh process is + + + align:start position:0% +is that the uh process is +is limited by the diffusion of water + + align:start position:0% +is limited by the diffusion of water + + + align:start position:0% +is limited by the diffusion of water +vapor + + align:start position:0% + + + + align:start position:0% + +away from the droplet + + align:start position:0% + + + + align:start position:0% + +because essentially we have this little + + align:start position:0% +because essentially we have this little + + + align:start position:0% +because essentially we have this little +drop we have a little droplet here with + + align:start position:0% +drop we have a little droplet here with + + + align:start position:0% +drop we have a little droplet here with +a certain + + align:start position:0% +a certain + + + align:start position:0% +a certain +size r which is now going to be varying + + align:start position:0% +size r which is now going to be varying + + + align:start position:0% +size r which is now going to be varying +with time + + align:start position:0% +with time + + + align:start position:0% +with time +so it has a radius r of t and + + align:start position:0% +so it has a radius r of t and + + + align:start position:0% +so it has a radius r of t and +it's really close to the surface there's + + align:start position:0% +it's really close to the surface there's + + + align:start position:0% +it's really close to the surface there's +an equilibrium concentration + + align:start position:0% +an equilibrium concentration + + + align:start position:0% +an equilibrium concentration +we'll call it cw of water which depends + + align:start position:0% +we'll call it cw of water which depends + + + align:start position:0% +we'll call it cw of water which depends +on the temperature so that's kind of + + align:start position:0% +on the temperature so that's kind of + + + align:start position:0% +on the temperature so that's kind of +that's the saturation concentration of + + align:start position:0% +that's the saturation concentration of + + + align:start position:0% +that's the saturation concentration of +water vapor + + align:start position:0% +water vapor + + + align:start position:0% +water vapor +in the air but then if the water is + + align:start position:0% +in the air but then if the water is + + + align:start position:0% +in the air but then if the water is +going to evaporate more it would create + + align:start position:0% +going to evaporate more it would create + + + align:start position:0% +going to evaporate more it would create +more concentration which would then + + align:start position:0% +more concentration which would then + + + align:start position:0% +more concentration which would then +recondense on the particles so for order + + align:start position:0% +recondense on the particles so for order + + + align:start position:0% +recondense on the particles so for order +for it to continue condensing or + + align:start position:0% +for it to continue condensing or + + + align:start position:0% +for it to continue condensing or +continue evaporating that water vapor + + align:start position:0% +continue evaporating that water vapor + + + align:start position:0% +continue evaporating that water vapor +that is produced has to diffuse away + + align:start position:0% +that is produced has to diffuse away + + + align:start position:0% +that is produced has to diffuse away +so there's going to be a gradient of + + align:start position:0% +so there's going to be a gradient of + + + align:start position:0% +so there's going to be a gradient of +water vapor + + align:start position:0% +water vapor + + + align:start position:0% +water vapor +going outwards from cw + + align:start position:0% +going outwards from cw + + + align:start position:0% +going outwards from cw +is the concentration you know at + + align:start position:0% +is the concentration you know at + + + align:start position:0% +is the concentration you know at +position r + + align:start position:0% +position r + + + align:start position:0% +position r +and then far away there is + + align:start position:0% +and then far away there is + + + align:start position:0% +and then far away there is +a sort of diffusion layer thickness + + align:start position:0% +a sort of diffusion layer thickness + + + align:start position:0% +a sort of diffusion layer thickness +delta and far beyond the diffusion layer + + align:start position:0% +delta and far beyond the diffusion layer + + + align:start position:0% +delta and far beyond the diffusion layer +thickness the concentration is going to + + align:start position:0% +thickness the concentration is going to + + + align:start position:0% +thickness the concentration is going to +approach the equilibrium concentration + + align:start position:0% +approach the equilibrium concentration + + + align:start position:0% +approach the equilibrium concentration +in the ambient air + + align:start position:0% +in the ambient air + + + align:start position:0% +in the ambient air +c at infinity is going to be cw + + align:start position:0% +c at infinity is going to be cw + + + align:start position:0% +c at infinity is going to be cw +times the relative humidity so that's + + align:start position:0% +times the relative humidity so that's + + + align:start position:0% +times the relative humidity so that's +the ratio of the concentration of water + + align:start position:0% +the ratio of the concentration of water + + + align:start position:0% +the ratio of the concentration of water +vapor in the air + + align:start position:0% +vapor in the air + + + align:start position:0% +vapor in the air +to the saturation concentration cw by + + align:start position:0% +to the saturation concentration cw by + + + align:start position:0% +to the saturation concentration cw by +definition + + align:start position:0% +definition + + + align:start position:0% +definition +okay now the math problem that we have + + align:start position:0% +okay now the math problem that we have + + + align:start position:0% +okay now the math problem that we have +to solve + + align:start position:0% +to solve + + + align:start position:0% +to solve +for this diffusion problem with a moving + + align:start position:0% +for this diffusion problem with a moving + + + align:start position:0% +for this diffusion problem with a moving +boundary in this case + + align:start position:0% +boundary in this case + + + align:start position:0% +boundary in this case +but we'll assume it's pseudo steady is + + align:start position:0% +but we'll assume it's pseudo steady is + + + align:start position:0% +but we'll assume it's pseudo steady is +dc dt + + align:start position:0% +dc dt + + + align:start position:0% +dc dt +is the diffusion coefficient of water + + align:start position:0% +is the diffusion coefficient of water + + + align:start position:0% +is the diffusion coefficient of water +times the laplacian of c so just the + + align:start position:0% +times the laplacian of c so just the + + + align:start position:0% +times the laplacian of c so just the +diffusion equation + + align:start position:0% +diffusion equation + + + align:start position:0% +diffusion equation +with these two boundary conditions now + + align:start position:0% +with these two boundary conditions now + + + align:start position:0% +with these two boundary conditions now +an interesting aspect of + + align:start position:0% +an interesting aspect of + + + align:start position:0% +an interesting aspect of +three-dimensional spherical diffusion is + + align:start position:0% +three-dimensional spherical diffusion is + + + align:start position:0% +three-dimensional spherical diffusion is +that at first the diffusion layer grows + + align:start position:0% +that at first the diffusion layer grows + + + align:start position:0% +that at first the diffusion layer grows +but it very quickly reaches a steady + + align:start position:0% +but it very quickly reaches a steady + + + align:start position:0% +but it very quickly reaches a steady +state and if we assume that that + + align:start position:0% +state and if we assume that that + + + align:start position:0% +state and if we assume that that +diffusion time to reach this distance + + align:start position:0% +diffusion time to reach this distance + + + align:start position:0% +diffusion time to reach this distance +delta + + align:start position:0% +delta + + + align:start position:0% +delta +is uh fast so they reach the steady + + align:start position:0% +is uh fast so they reach the steady + + + align:start position:0% +is uh fast so they reach the steady +state it's so it's a kind of + + align:start position:0% +state it's so it's a kind of + + + align:start position:0% +state it's so it's a kind of +quasi-steady or studio steady shrinking + + align:start position:0% +quasi-steady or studio steady shrinking + + + align:start position:0% +quasi-steady or studio steady shrinking +of the droplet with sort of a diffusion + + align:start position:0% +of the droplet with sort of a diffusion + + + align:start position:0% +of the droplet with sort of a diffusion +layer around it that's always + + align:start position:0% +layer around it that's always + + + align:start position:0% +layer around it that's always +kind of at the steady value then it + + align:start position:0% +kind of at the steady value then it + + + align:start position:0% +kind of at the steady value then it +turns out that this diffusion layer + + align:start position:0% +turns out that this diffusion layer + + + align:start position:0% +turns out that this diffusion layer +is avoided the particle size so as the + + align:start position:0% +is avoided the particle size so as the + + + align:start position:0% +is avoided the particle size so as the +particle shrinks the diffusion layer + + align:start position:0% +particle shrinks the diffusion layer + + + align:start position:0% +particle shrinks the diffusion layer +also shrinks + + align:start position:0% +also shrinks + + + align:start position:0% +also shrinks +but it has a well-defined thickness as + + align:start position:0% +but it has a well-defined thickness as + + + align:start position:0% +but it has a well-defined thickness as +opposed to diffusion in one or two + + align:start position:0% +opposed to diffusion in one or two + + + align:start position:0% +opposed to diffusion in one or two +dimensions where the diffusion layer + + align:start position:0% +dimensions where the diffusion layer + + + align:start position:0% +dimensions where the diffusion layer +just keeps growing out to infinity for + + align:start position:0% +just keeps growing out to infinity for + + + align:start position:0% +just keeps growing out to infinity for +example like square root of time + + align:start position:0% +example like square root of time + + + align:start position:0% +example like square root of time +you don't reach a steady state in an + + align:start position:0% +you don't reach a steady state in an + + + align:start position:0% +you don't reach a steady state in an +infinite domain + + align:start position:0% +infinite domain + + + align:start position:0% +infinite domain +so the bottom line of this calculation + + align:start position:0% +so the bottom line of this calculation + + + align:start position:0% +so the bottom line of this calculation +which i will not go through right now + + align:start position:0% +which i will not go through right now + + + align:start position:0% +which i will not go through right now +is that the flux of water on the surface + + align:start position:0% +is that the flux of water on the surface + + + align:start position:0% +is that the flux of water on the surface +is the area of the surface at a given + + align:start position:0% +is the area of the surface at a given + + + align:start position:0% +is the area of the surface at a given +moment where + + align:start position:0% +moment where + + + align:start position:0% +moment where +the sizes are times + + align:start position:0% +the sizes are times + + + align:start position:0% +the sizes are times +the essentially fixed law + + align:start position:0% +the essentially fixed law + + + align:start position:0% +the essentially fixed law +where the driving force the change in + + align:start position:0% +where the driving force the change in + + + align:start position:0% +where the driving force the change in +concentration from the surface to the + + align:start position:0% +concentration from the surface to the + + + align:start position:0% +concentration from the surface to the +bulk + + align:start position:0% +bulk + + + align:start position:0% +bulk +is cw times one minus relative humidity + + align:start position:0% +is cw times one minus relative humidity + + + align:start position:0% +is cw times one minus relative humidity +the diffusivity of water and then + + align:start position:0% +the diffusivity of water and then + + + align:start position:0% +the diffusivity of water and then +divided by delta the diffusion layer + + align:start position:0% +divided by delta the diffusion layer + + + align:start position:0% +divided by delta the diffusion layer +thickness and it turns out that with + + align:start position:0% +thickness and it turns out that with + + + align:start position:0% +thickness and it turns out that with +these coefficients here that's it turns + + align:start position:0% +these coefficients here that's it turns + + + align:start position:0% +these coefficients here that's it turns +out to be exactly r so this is not a + + align:start position:0% +out to be exactly r so this is not a + + + align:start position:0% +out to be exactly r so this is not a +scaling result but actually an exact + + align:start position:0% +scaling result but actually an exact + + + align:start position:0% +scaling result but actually an exact +result + + align:start position:0% +result + + + align:start position:0% +result +for pseudosteady spherical diffusion of + + align:start position:0% +for pseudosteady spherical diffusion of + + + align:start position:0% +for pseudosteady spherical diffusion of +water vapor + + align:start position:0% +water vapor + + + align:start position:0% +water vapor +so now we have the flux on the surface + + align:start position:0% +so now we have the flux on the surface + + + align:start position:0% +so now we have the flux on the surface +it's uniform on the surface + + align:start position:0% +it's uniform on the surface + + + align:start position:0% +it's uniform on the surface +and it's consumed to be pseudo steady + + align:start position:0% +and it's consumed to be pseudo steady + + + align:start position:0% +and it's consumed to be pseudo steady +and so then i can write down + + align:start position:0% +and so then i can write down + + + align:start position:0% +and so then i can write down +that the change in the size of the water + + align:start position:0% +that the change in the size of the water + + + align:start position:0% +that the change in the size of the water +droplet + + align:start position:0% +droplet + + + align:start position:0% +droplet +volume which is 4 pi over cube 3 + + align:start position:0% +volume which is 4 pi over cube 3 + + + align:start position:0% +volume which is 4 pi over cube 3 +4 pi over 3 r cubed is equal to minus + + align:start position:0% +4 pi over 3 r cubed is equal to minus + + + align:start position:0% +4 pi over 3 r cubed is equal to minus +the volume of a water molecule + + align:start position:0% +the volume of a water molecule + + + align:start position:0% +the volume of a water molecule +times the flux of water so that's + + align:start position:0% +times the flux of water so that's + + + align:start position:0% +times the flux of water so that's +basically + + align:start position:0% +basically + + + align:start position:0% +basically +my volume or mass balance of water + + align:start position:0% +my volume or mass balance of water + + + align:start position:0% +my volume or mass balance of water +so if i plug this in here then i get dr + + align:start position:0% +so if i plug this in here then i get dr + + + align:start position:0% +so if i plug this in here then i get dr +dt is equal to uh + + align:start position:0% +dt is equal to uh + + + align:start position:0% +dt is equal to uh +let's see collecting all the terms here + + align:start position:0% +let's see collecting all the terms here + + + align:start position:0% +let's see collecting all the terms here +so derivative r cubed + + align:start position:0% +so derivative r cubed + + + align:start position:0% +so derivative r cubed +is uh 2 r is 3r squared so the 3's + + align:start position:0% +is uh 2 r is 3r squared so the 3's + + + align:start position:0% +is uh 2 r is 3r squared so the 3's +cancel + + align:start position:0% +cancel + + + align:start position:0% +cancel +and then i have a 4 pi r squared which + + align:start position:0% +and then i have a 4 pi r squared which + + + align:start position:0% +and then i have a 4 pi r squared which +cancels this 4 pi + + align:start position:0% +cancels this 4 pi + + + align:start position:0% +cancels this 4 pi +squared so i just have dr dt is minus + + align:start position:0% +squared so i just have dr dt is minus + + + align:start position:0% +squared so i just have dr dt is minus +vw dw cw 1 minus + + align:start position:0% +vw dw cw 1 minus + + + align:start position:0% +vw dw cw 1 minus +rh divided by r + + align:start position:0% + + + + align:start position:0% + +if i put this r on the other side here + + align:start position:0% +if i put this r on the other side here + + + align:start position:0% +if i put this r on the other side here +then i have let's continue the + + align:start position:0% +then i have let's continue the + + + align:start position:0% +then i have let's continue the +derivation here + + align:start position:0% +derivation here + + + align:start position:0% +derivation here +i have r dr + + align:start position:0% +i have r dr + + + align:start position:0% +i have r dr +dt is equal to all this stuff + + align:start position:0% +dt is equal to all this stuff + + + align:start position:0% +dt is equal to all this stuff +so minus dw + + align:start position:0% +so minus dw + + + align:start position:0% +so minus dw +dwcw1 minus rh + + align:start position:0% +dwcw1 minus rh + + + align:start position:0% +dwcw1 minus rh +and then this expression here can be + + align:start position:0% +and then this expression here can be + + + align:start position:0% +and then this expression here can be +written as + + align:start position:0% +written as + + + align:start position:0% +written as +one-half the derivative + + align:start position:0% +one-half the derivative + + + align:start position:0% +one-half the derivative +of r squared so we find is that r + + align:start position:0% +of r squared so we find is that r + + + align:start position:0% +of r squared so we find is that r +squared is linear in time + + align:start position:0% +squared is linear in time + + + align:start position:0% +squared is linear in time +and then using the boundary condition + + align:start position:0% +and then using the boundary condition + + + align:start position:0% +and then using the boundary condition +that we + + align:start position:0% +that we + + + align:start position:0% +that we +start out at a certain initial value r + + align:start position:0% +start out at a certain initial value r + + + align:start position:0% +start out at a certain initial value r +naught + + align:start position:0% +naught + + + align:start position:0% +naught +then i'm going to get that the r of t + + align:start position:0% +then i'm going to get that the r of t + + + align:start position:0% +then i'm going to get that the r of t +is the initial value r naught + + align:start position:0% +is the initial value r naught + + + align:start position:0% +is the initial value r naught +times the square root of one minus t + + align:start position:0% +times the square root of one minus t + + + align:start position:0% +times the square root of one minus t +over a certain evaporation time + + align:start position:0% +over a certain evaporation time + + + align:start position:0% +over a certain evaporation time +and that evaporation time + + align:start position:0% +and that evaporation time + + + align:start position:0% +and that evaporation time +is given here by + + align:start position:0% + + + + align:start position:0% + +r0 squared uh + + align:start position:0% +r0 squared uh + + + align:start position:0% +r0 squared uh +times basically all these coefficients + + align:start position:0% +times basically all these coefficients + + + align:start position:0% +times basically all these coefficients +here + + align:start position:0% +here + + + align:start position:0% +here +uh where i'll separate out the effective + + align:start position:0% +uh where i'll separate out the effective + + + align:start position:0% +uh where i'll separate out the effective +humidity + + align:start position:0% +humidity + + + align:start position:0% +humidity +and then a bunch of other coefficients + + align:start position:0% +and then a bunch of other coefficients + + + align:start position:0% +and then a bunch of other coefficients +which you can see have units of length + + align:start position:0% +which you can see have units of length + + + align:start position:0% +which you can see have units of length +squared + + align:start position:0% +squared + + + align:start position:0% +squared +over time because our zero is a length + + align:start position:0% +over time because our zero is a length + + + align:start position:0% +over time because our zero is a length +squared so it's effectively some kind of + + align:start position:0% +squared so it's effectively some kind of + + + align:start position:0% +squared so it's effectively some kind of +diffusivity + + align:start position:0% +diffusivity + + + align:start position:0% +diffusivity +and what we get from this calculation is + + align:start position:0% +and what we get from this calculation is + + + align:start position:0% +and what we get from this calculation is +that this effective diffusivity that + + align:start position:0% +that this effective diffusivity that + + + align:start position:0% +that this effective diffusivity that +goes into this + + align:start position:0% +goes into this + + + align:start position:0% +goes into this +expression is there's a factor two from + + align:start position:0% +expression is there's a factor two from + + + align:start position:0% +expression is there's a factor two from +this guy there's a two + + align:start position:0% +this guy there's a two + + + align:start position:0% +this guy there's a two +v w d w c w + + align:start position:0% +v w d w c w + + + align:start position:0% +v w d w c w +and if you plug in values for water + + align:start position:0% +and if you plug in values for water + + + align:start position:0% +and if you plug in values for water +vapor for the saturation pressure and + + align:start position:0% +vapor for the saturation pressure and + + + align:start position:0% +vapor for the saturation pressure and +the diffusivity + + align:start position:0% +the diffusivity + + + align:start position:0% +the diffusivity +and the volume of water in air then this + + align:start position:0% +and the volume of water in air then this + + + align:start position:0% +and the volume of water in air then this +coefficient turns out to be 1.2 + + align:start position:0% +coefficient turns out to be 1.2 + + + align:start position:0% +coefficient turns out to be 1.2 +times 10 to the minus 9 meters squared + + align:start position:0% +times 10 to the minus 9 meters squared + + + align:start position:0% +times 10 to the minus 9 meters squared +per second + + align:start position:0% +per second + + + align:start position:0% +per second +for pure water + + align:start position:0% +for pure water + + + align:start position:0% +for pure water +and that's where you get now the second + + align:start position:0% +and that's where you get now the second + + + align:start position:0% +and that's where you get now the second +part of the wells theory which is the + + align:start position:0% +part of the wells theory which is the + + + align:start position:0% +part of the wells theory which is the +evaporation + + align:start position:0% +evaporation + + + align:start position:0% +evaporation +which gives you a curve looking like + + align:start position:0% +which gives you a curve looking like + + + align:start position:0% +which gives you a curve looking like +this + + align:start position:0% + + + + align:start position:0% + +so that there's this sort of in this + + align:start position:0% +so that there's this sort of in this + + + align:start position:0% +so that there's this sort of in this +theory a natural + + align:start position:0% +theory a natural + + + align:start position:0% +theory a natural +crossover between + + align:start position:0% +crossover between + + + align:start position:0% +crossover between +large drops which in this case here are + + align:start position:0% +large drops which in this case here are + + + align:start position:0% +large drops which in this case here are +ones that are large enough to settle + + align:start position:0% +ones that are large enough to settle + + + align:start position:0% +ones that are large enough to settle +out of the fluid before they evaporate + + align:start position:0% +out of the fluid before they evaporate + + + align:start position:0% +out of the fluid before they evaporate +and + + align:start position:0% +and + + + align:start position:0% +and +small drops which + + align:start position:0% +small drops which + + + align:start position:0% +small drops which +evaporate + + align:start position:0% + + + + align:start position:0% + +on the other hand for true biological + + align:start position:0% +on the other hand for true biological + + + align:start position:0% +on the other hand for true biological +fluids that + + align:start position:0% +fluids that + + + align:start position:0% +fluids that +appear in respiratory droplets + + align:start position:0% +appear in respiratory droplets + + + align:start position:0% +appear in respiratory droplets +the evaporation is limited by solutes + + align:start position:0% +the evaporation is limited by solutes + + + align:start position:0% +the evaporation is limited by solutes +and salts + + align:start position:0% +and salts + + + align:start position:0% +and salts +which stop the evaporation and in fact + + align:start position:0% +which stop the evaporation and in fact + + + align:start position:0% +which stop the evaporation and in fact +can attract even more water in some + + align:start position:0% +can attract even more water in some + + + align:start position:0% +can attract even more water in some +cases + + align:start position:0% +cases + + + align:start position:0% +cases +so that the evaporation part of it is + + align:start position:0% +so that the evaporation part of it is + + + align:start position:0% +so that the evaporation part of it is +not as accurate + + align:start position:0% +not as accurate + + + align:start position:0% +not as accurate +and we tend to see that the settling + + align:start position:0% +and we tend to see that the settling + + + align:start position:0% +and we tend to see that the settling +part is more important to consider + + align:start position:0% +part is more important to consider + + + align:start position:0% +part is more important to consider +uh given an equilibrium distribution of + + align:start position:0% +uh given an equilibrium distribution of + + + align:start position:0% +uh given an equilibrium distribution of +droplets that has been measured and + + align:start position:0% +droplets that has been measured and + + + align:start position:0% +droplets that has been measured and +is understood to come from different + + align:start position:0% +is understood to come from different + + + align:start position:0% +is understood to come from different +types of respiration \ No newline at end of file diff --git a/AIucNcAQE3A.txt b/AIucNcAQE3A.txt new file mode 100644 index 0000000000000000000000000000000000000000..59d597e7582b197d2a5ed13ce24c7fcf7e4ad1ae --- /dev/null +++ b/AIucNcAQE3A.txt @@ -0,0 +1,387 @@ +align:start position:0% + +can you tell me uh your your team name + + align:start position:0% +can you tell me uh your your team name + + + align:start position:0% +can you tell me uh your your team name +and introduce the members of your team + + align:start position:0% +and introduce the members of your team + + + align:start position:0% +and introduce the members of your team +please uh we're Team Firebolt and I'm + + align:start position:0% +please uh we're Team Firebolt and I'm + + + align:start position:0% +please uh we're Team Firebolt and I'm +Chris Pinos I'm Mariel John and I'm + + align:start position:0% +Chris Pinos I'm Mariel John and I'm + + + align:start position:0% +Chris Pinos I'm Mariel John and I'm +Elvia + + align:start position:0% +Elvia + + + align:start position:0% +Elvia +sedun well you made it this far uh how + + align:start position:0% +sedun well you made it this far uh how + + + align:start position:0% +sedun well you made it this far uh how +are you + + align:start position:0% +are you + + + align:start position:0% +are you +feeling pretty good we're proud of the + + align:start position:0% +feeling pretty good we're proud of the + + + align:start position:0% +feeling pretty good we're proud of the +work we've + + align:start position:0% +work we've + + + align:start position:0% +work we've +done uh we we're pretty good we have a + + align:start position:0% +done uh we we're pretty good we have a + + + align:start position:0% +done uh we we're pretty good we have a +uh second place right now but we're + + align:start position:0% +uh second place right now but we're + + + align:start position:0% +uh second place right now but we're +hoping to get first today the next + + align:start position:0% +hoping to get first today the next + + + align:start position:0% +hoping to get first today the next +flight second place huh so so you + + align:start position:0% +flight second place huh so so you + + + align:start position:0% +flight second place huh so so you +competed yesterday yes so what's + + align:start position:0% +competed yesterday yes so what's + + + align:start position:0% +competed yesterday yes so what's +different today what what changes did + + align:start position:0% +different today what what changes did + + + align:start position:0% +different today what what changes did +you make uh we made uh egg canisters + + align:start position:0% +you make uh we made uh egg canisters + + + align:start position:0% +you make uh we made uh egg canisters +that have a lot less drag than the ones + + align:start position:0% +that have a lot less drag than the ones + + + align:start position:0% +that have a lot less drag than the ones +we did yesterday and you think that's + + align:start position:0% +we did yesterday and you think that's + + + align:start position:0% +we did yesterday and you think that's +going to give you the edge + + align:start position:0% +going to give you the edge + + + align:start position:0% +going to give you the edge +yeah what's the most notable design + + align:start position:0% +yeah what's the most notable design + + + align:start position:0% +yeah what's the most notable design +feature of your aircraft what advantage + + align:start position:0% +feature of your aircraft what advantage + + + align:start position:0% +feature of your aircraft what advantage +do you think it gives you uh well we + + align:start position:0% +do you think it gives you uh well we + + + align:start position:0% +do you think it gives you uh well we +have an a really large wingspan which + + align:start position:0% +have an a really large wingspan which + + + align:start position:0% +have an a really large wingspan which +gives us probably the most lift of any + + align:start position:0% +gives us probably the most lift of any + + + align:start position:0% +gives us probably the most lift of any +team here um that gives us lots of drag + + align:start position:0% +team here um that gives us lots of drag + + + align:start position:0% +team here um that gives us lots of drag +but uh I think the lift is the best + + align:start position:0% +but uh I think the lift is the best + + + align:start position:0% +but uh I think the lift is the best +feature + + align:start position:0% +feature + + + align:start position:0% +feature +you've been working on this project as a + + align:start position:0% +you've been working on this project as a + + + align:start position:0% +you've been working on this project as a +team for most of the semester what's + + align:start position:0% +team for most of the semester what's + + + align:start position:0% +team for most of the semester what's +been the most enjoyable part of the + + align:start position:0% +been the most enjoyable part of the + + + align:start position:0% +been the most enjoyable part of the +process I think maybe just spending time + + align:start position:0% +process I think maybe just spending time + + + align:start position:0% +process I think maybe just spending time +in the lab together when we're just kind + + align:start position:0% +in the lab together when we're just kind + + + align:start position:0% +in the lab together when we're just kind +of working on the plane and building or + + align:start position:0% +of working on the plane and building or + + + align:start position:0% +of working on the plane and building or +thinking of ideas of how we can make it + + align:start position:0% +thinking of ideas of how we can make it + + + align:start position:0% +thinking of ideas of how we can make it +better yeah I mean it's nice to uh get a + + align:start position:0% +better yeah I mean it's nice to uh get a + + + align:start position:0% +better yeah I mean it's nice to uh get a +chance to do something Hands-On as + + align:start position:0% +chance to do something Hands-On as + + + align:start position:0% +chance to do something Hands-On as +opposed to you know just problem sets + + align:start position:0% +opposed to you know just problem sets + + + align:start position:0% +opposed to you know just problem sets +and + + align:start position:0% +and + + + align:start position:0% +and +stuff so what was toughest about + + align:start position:0% +stuff so what was toughest about + + + align:start position:0% +stuff so what was toughest about +engineering this + + align:start position:0% + + + + align:start position:0% + +system I'd like to it doesn't have + + align:start position:0% +system I'd like to it doesn't have + + + align:start position:0% +system I'd like to it doesn't have +things uh things break a lot and uh + + align:start position:0% +things uh things break a lot and uh + + + align:start position:0% +things uh things break a lot and uh +nothing ever goes the way you want so + + align:start position:0% +nothing ever goes the way you want so + + + align:start position:0% +nothing ever goes the way you want so +you have to you know redesign on the Fly + + align:start position:0% +you have to you know redesign on the Fly + + + align:start position:0% +you have to you know redesign on the Fly +and like half of the designing is taking + + align:start position:0% +and like half of the designing is taking + + + align:start position:0% +and like half of the designing is taking +place just in these last few days really + + align:start position:0% +place just in these last few days really + + + align:start position:0% +place just in these last few days really +feels + + align:start position:0% +feels + + + align:start position:0% +feels +like all right well thanks very much you + + align:start position:0% +like all right well thanks very much you + + + align:start position:0% +like all right well thanks very much you +guys good luck with your flight \ No newline at end of file diff --git a/AKqq9-c6uMo.txt b/AKqq9-c6uMo.txt new file mode 100644 index 0000000000000000000000000000000000000000..ed2f5ba77efd6cdbb67124aaa54bfa8e7f383c22 --- /dev/null +++ b/AKqq9-c6uMo.txt @@ -0,0 +1,9979 @@ +align:start position:0% + +all right good morning everybody today + + align:start position:0% +all right good morning everybody today + + + align:start position:0% +all right good morning everybody today +is not a thermodynamics lecture by me we + + align:start position:0% +is not a thermodynamics lecture by me we + + + align:start position:0% +is not a thermodynamics lecture by me we +have a guest lecture by professing Greg + + align:start position:0% +have a guest lecture by professing Greg + + + align:start position:0% +have a guest lecture by professing Greg +Olsen and we just finished a lot of work + + align:start position:0% +Olsen and we just finished a lot of work + + + align:start position:0% +Olsen and we just finished a lot of work +with thermocalc and calfat in general + + align:start position:0% +with thermocalc and calfat in general + + + align:start position:0% +with thermocalc and calfat in general +and solution model in binary phase + + align:start position:0% +and solution model in binary phase + + + align:start position:0% +and solution model in binary phase +diagrams and I've told you throughout + + align:start position:0% +diagrams and I've told you throughout + + + align:start position:0% +diagrams and I've told you throughout +the entire semester that thermodynamic + + align:start position:0% +the entire semester that thermodynamic + + + align:start position:0% +the entire semester that thermodynamic +data is valuable and allows you to make + + align:start position:0% +data is valuable and allows you to make + + + align:start position:0% +data is valuable and allows you to make +make predictions that's why it's + + align:start position:0% +make predictions that's why it's + + + align:start position:0% +make predictions that's why it's +valuable and those predictions allow you + + align:start position:0% +valuable and those predictions allow you + + + align:start position:0% +valuable and those predictions allow you +to make real things in the real world + + align:start position:0% +to make real things in the real world + + + align:start position:0% +to make real things in the real world +possible and um so far you've just had + + align:start position:0% +possible and um so far you've just had + + + align:start position:0% +possible and um so far you've just had +to take my word for it right so so the + + align:start position:0% +to take my word for it right so so the + + + align:start position:0% +to take my word for it right so so the +point of today's guest lecture is that + + align:start position:0% +point of today's guest lecture is that + + + align:start position:0% +point of today's guest lecture is that +um so you can don't have to take my word + + align:start position:0% +um so you can don't have to take my word + + + align:start position:0% +um so you can don't have to take my word +for it anymore so I won't I'll just say + + align:start position:0% +for it anymore so I won't I'll just say + + + align:start position:0% +for it anymore so I won't I'll just say +that Professor olssen is world famous + + align:start position:0% +that Professor olssen is world famous + + + align:start position:0% +that Professor olssen is world famous +for using thermodynamic data um to for + + align:start position:0% +for using thermodynamic data um to for + + + align:start position:0% +for using thermodynamic data um to for +real world impact and I leave it at that + + align:start position:0% +real world impact and I leave it at that + + + align:start position:0% +real world impact and I leave it at that +is that okay Greg that's sufficient I + + align:start position:0% +is that okay Greg that's sufficient I + + + align:start position:0% +is that okay Greg that's sufficient I +think yes yes all right let's hope it's + + align:start position:0% +think yes yes all right let's hope it's + + + align:start position:0% +think yes yes all right let's hope it's +positive impact yes okay very good + + align:start position:0% +positive impact yes okay very good + + + align:start position:0% +positive impact yes okay very good +indeed uh so I'll hand it I'll hand it + + align:start position:0% +indeed uh so I'll hand it I'll hand it + + + align:start position:0% +indeed uh so I'll hand it I'll hand it +over to you all right let me attempt my + + align:start position:0% +over to you all right let me attempt my + + + align:start position:0% +over to you all right let me attempt my +screen + + align:start position:0% + + + + align:start position:0% + +share all right my presentation will be + + align:start position:0% +share all right my presentation will be + + + align:start position:0% +share all right my presentation will be +from the perspective of my University + + align:start position:0% +from the perspective of my University + + + align:start position:0% +from the perspective of my University +day job as well as the activities of our + + align:start position:0% +day job as well as the activities of our + + + align:start position:0% +day job as well as the activities of our +computational materials design company + + align:start position:0% +computational materials design company + + + align:start position:0% +computational materials design company +questech and they ongoing collaborations + + align:start position:0% +questech and they ongoing collaborations + + + align:start position:0% +questech and they ongoing collaborations +through the uh Chicago based chimed + + align:start position:0% +through the uh Chicago based chimed + + + align:start position:0% +through the uh Chicago based chimed +materials Design + + align:start position:0% +materials Design + + + align:start position:0% +materials Design +Center uh as thermocalc professor of the + + align:start position:0% +Center uh as thermocalc professor of the + + + align:start position:0% +Center uh as thermocalc professor of the +practice uh my job description is to + + align:start position:0% +practice uh my job description is to + + + align:start position:0% +practice uh my job description is to +make MIT a global Beacon of calad + + align:start position:0% +make MIT a global Beacon of calad + + + align:start position:0% +make MIT a global Beacon of calad +Technology into which we are recruiting + + align:start position:0% +Technology into which we are recruiting + + + align:start position:0% +Technology into which we are recruiting +you and in in uh in the uh in support of + + align:start position:0% +you and in in uh in the uh in support of + + + align:start position:0% +you and in in uh in the uh in support of +that uh we've actually had a range that + + align:start position:0% +that uh we've actually had a range that + + + align:start position:0% +that uh we've actually had a range that +uh MIT would host uh this year's + + align:start position:0% +uh MIT would host uh this year's + + + align:start position:0% +uh MIT would host uh this year's +International calad Conference but + + align:start position:0% +International calad Conference but + + + align:start position:0% +International calad Conference but +unfortunately due to the pandemic we've + + align:start position:0% +unfortunately due to the pandemic we've + + + align:start position:0% +unfortunately due to the pandemic we've +had to post ponent a couple years but I + + align:start position:0% +had to post ponent a couple years but I + + + align:start position:0% +had to post ponent a couple years but I +hope uh you'll still be around to to to + + align:start position:0% +hope uh you'll still be around to to to + + + align:start position:0% +hope uh you'll still be around to to to +join us when that + + align:start position:0% +join us when that + + + align:start position:0% +join us when that +happens uh and I would like you uh + + align:start position:0% +happens uh and I would like you uh + + + align:start position:0% +happens uh and I would like you uh +throughout uh don't hesitate to + + align:start position:0% +throughout uh don't hesitate to + + + align:start position:0% +throughout uh don't hesitate to +interrupt uh just unmute yourself and + + align:start position:0% +interrupt uh just unmute yourself and + + + align:start position:0% +interrupt uh just unmute yourself and +and yell at me if you'd like to discuss + + align:start position:0% + + + + align:start position:0% + +anything uh the context of this + + align:start position:0% +anything uh the context of this + + + align:start position:0% +anything uh the context of this +technology is the national materials + + align:start position:0% +technology is the national materials + + + align:start position:0% +technology is the national materials +genome initiative that's a presidential + + align:start position:0% +genome initiative that's a presidential + + + align:start position:0% +genome initiative that's a presidential +initiative announced by President Obama + + align:start position:0% +initiative announced by President Obama + + + align:start position:0% +initiative announced by President Obama +a decade ago uh intended as a decadal + + align:start position:0% +a decade ago uh intended as a decadal + + + align:start position:0% +a decade ago uh intended as a decadal +initiative but in fact a recent National + + align:start position:0% +initiative but in fact a recent National + + + align:start position:0% +initiative but in fact a recent National +Academy study has recommended that it + + align:start position:0% +Academy study has recommended that it + + + align:start position:0% +Academy study has recommended that it +continue for another + + align:start position:0% +continue for another + + + align:start position:0% +continue for another +decade and the uh overarching goal of + + align:start position:0% +decade and the uh overarching goal of + + + align:start position:0% +decade and the uh overarching goal of +this initiative is to build out the + + align:start position:0% +this initiative is to build out the + + + align:start position:0% +this initiative is to build out the +databases and tools that would allow us + + align:start position:0% +databases and tools that would allow us + + + align:start position:0% +databases and tools that would allow us +to take what has been historically a 10 + + align:start position:0% +to take what has been historically a 10 + + + align:start position:0% +to take what has been historically a 10 +to 20 year materials development cycle + + align:start position:0% +to 20 year materials development cycle + + + align:start position:0% +to 20 year materials development cycle +and compress that by at least uh + + align:start position:0% + + + + align:start position:0% + +50% the metaphor of the genome uh is + + align:start position:0% +50% the metaphor of the genome uh is + + + align:start position:0% +50% the metaphor of the genome uh is +discussed in the National Academy study + + align:start position:0% +discussed in the National Academy study + + + align:start position:0% +discussed in the National Academy study +going back to + + align:start position:0% +going back to + + + align:start position:0% +going back to +2004 uh on this very subject of + + align:start position:0% +2004 uh on this very subject of + + + align:start position:0% +2004 uh on this very subject of +accelerating the technology transition + + align:start position:0% +accelerating the technology transition + + + align:start position:0% +accelerating the technology transition +of materials and + + align:start position:0% +of materials and + + + align:start position:0% +of materials and +processes uh so it reviewed uh the best + + align:start position:0% +processes uh so it reviewed uh the best + + + align:start position:0% +processes uh so it reviewed uh the best +that had been achieved at that time and + + align:start position:0% +that had been achieved at that time and + + + align:start position:0% +that had been achieved at that time and +then looking forward looked at the + + align:start position:0% +then looking forward looked at the + + + align:start position:0% +then looking forward looked at the +analogy of the human genome initiative + + align:start position:0% +analogy of the human genome initiative + + + align:start position:0% +analogy of the human genome initiative +as possibly the greatest engineering + + align:start position:0% +as possibly the greatest engineering + + + align:start position:0% +as possibly the greatest engineering +database in history that was created not + + align:start position:0% +database in history that was created not + + + align:start position:0% +database in history that was created not +just to support the life sciences but + + align:start position:0% +just to support the life sciences but + + + align:start position:0% +just to support the life sciences but +really to support science-based medicine + + align:start position:0% +really to support science-based medicine + + + align:start position:0% +really to support science-based medicine +an example of which is that mRNA vaccine + + align:start position:0% +an example of which is that mRNA vaccine + + + align:start position:0% +an example of which is that mRNA vaccine +we're all getting these days uh so it's + + align:start position:0% +we're all getting these days uh so it's + + + align:start position:0% +we're all getting these days uh so it's +had a tremendous impact in allowing a + + align:start position:0% +had a tremendous impact in allowing a + + + align:start position:0% +had a tremendous impact in allowing a +more science-based approach to medicine + + align:start position:0% +more science-based approach to medicine + + + align:start position:0% +more science-based approach to medicine +so the concept of the materials genome + + align:start position:0% +so the concept of the materials genome + + + align:start position:0% +so the concept of the materials genome +from the start as uh called for in this + + align:start position:0% +from the start as uh called for in this + + + align:start position:0% +from the start as uh called for in this +2004 study uh was to build out an + + align:start position:0% +2004 study uh was to build out an + + + align:start position:0% +2004 study uh was to build out an +equally fundamental uh + + align:start position:0% +equally fundamental uh + + + align:start position:0% +equally fundamental uh +database uh with the idea that the human + + align:start position:0% +database uh with the idea that the human + + + align:start position:0% +database uh with the idea that the human +genome physically functions as a + + align:start position:0% +genome physically functions as a + + + align:start position:0% +genome physically functions as a +database that directs the Assembly of + + align:start position:0% +database that directs the Assembly of + + + align:start position:0% +database that directs the Assembly of +the structures of Life uh what are the + + align:start position:0% +the structures of Life uh what are the + + + align:start position:0% +the structures of Life uh what are the +equally fundamental parameters that + + align:start position:0% +equally fundamental parameters that + + + align:start position:0% +equally fundamental parameters that +direct the Assembly of the micr + + align:start position:0% +direct the Assembly of the micr + + + align:start position:0% +direct the Assembly of the micr +structure of materials and could we use + + align:start position:0% +structure of materials and could we use + + + align:start position:0% +structure of materials and could we use +such a system to not just support + + align:start position:0% +such a system to not just support + + + align:start position:0% +such a system to not just support +Material Science but to enable a new + + align:start position:0% +Material Science but to enable a new + + + align:start position:0% +Material Science but to enable a new +form of science-based materials + + align:start position:0% +form of science-based materials + + + align:start position:0% +form of science-based materials +engineering so it really was the + + align:start position:0% +engineering so it really was the + + + align:start position:0% +engineering so it really was the +ultimate engineering application and the + + align:start position:0% +ultimate engineering application and the + + + align:start position:0% +ultimate engineering application and the +ability to put our scientific + + align:start position:0% +ability to put our scientific + + + align:start position:0% +ability to put our scientific +understanding uh in a useful predictive + + align:start position:0% +understanding uh in a useful predictive + + + align:start position:0% +understanding uh in a useful predictive +form uh that really was the whole + + align:start position:0% +form uh that really was the whole + + + align:start position:0% +form uh that really was the whole +Central concept of this materialist + + align:start position:0% +Central concept of this materialist + + + align:start position:0% +Central concept of this materialist +genome initiative uh and the + + align:start position:0% +genome initiative uh and the + + + align:start position:0% +genome initiative uh and the +recommendation in 2004 uh is exactly the + + align:start position:0% +recommendation in 2004 uh is exactly the + + + align:start position:0% +recommendation in 2004 uh is exactly the +structure that was formed and then is + + align:start position:0% +structure that was formed and then is + + + align:start position:0% +structure that was formed and then is +continuing today now there have been + + align:start position:0% +continuing today now there have been + + + align:start position:0% +continuing today now there have been +many Academy studies uh acknowledging + + align:start position:0% +many Academy studies uh acknowledging + + + align:start position:0% +many Academy studies uh acknowledging +the new opportunity of computational + + align:start position:0% +the new opportunity of computational + + + align:start position:0% +the new opportunity of computational +materials engineering but one thing that + + align:start position:0% +materials engineering but one thing that + + + align:start position:0% +materials engineering but one thing that +was unique about the 2004 study was the + + align:start position:0% +was unique about the 2004 study was the + + + align:start position:0% +was unique about the 2004 study was the +leading role + + align:start position:0% +leading role + + + align:start position:0% +leading role +of a Global Network of small businesses + + align:start position:0% +of a Global Network of small businesses + + + align:start position:0% +of a Global Network of small businesses +that created and maintained this + + align:start position:0% +that created and maintained this + + + align:start position:0% +that created and maintained this +technology and made this possible uh and + + align:start position:0% +technology and made this possible uh and + + + align:start position:0% +technology and made this possible uh and +so this was a list that was constructed + + align:start position:0% +so this was a list that was constructed + + + align:start position:0% +so this was a list that was constructed +at in that report of what had already + + align:start position:0% +at in that report of what had already + + + align:start position:0% +at in that report of what had already +been made available at that time and + + align:start position:0% +been made available at that time and + + + align:start position:0% +been made available at that time and +demonstrated successes of the + + align:start position:0% +demonstrated successes of the + + + align:start position:0% +demonstrated successes of the +technology uh the principal mechanism by + + align:start position:0% +technology uh the principal mechanism by + + + align:start position:0% +technology uh the principal mechanism by +this the way that uh this technology has + + align:start position:0% +this the way that uh this technology has + + + align:start position:0% +this the way that uh this technology has +moved into major corporations has been + + align:start position:0% +moved into major corporations has been + + + align:start position:0% +moved into major corporations has been +by Acquisitions of various forms that + + align:start position:0% +by Acquisitions of various forms that + + + align:start position:0% +by Acquisitions of various forms that +have affected about a third of the + + align:start position:0% +have affected about a third of the + + + align:start position:0% +have affected about a third of the +companies on this chart so small + + align:start position:0% +companies on this chart so small + + + align:start position:0% +companies on this chart so small +business really did create this + + align:start position:0% +business really did create this + + + align:start position:0% +business really did create this +technology and and Lead the + + align:start position:0% +technology and and Lead the + + + align:start position:0% +technology and and Lead the +Way historic Milestone was a decade ago + + align:start position:0% +Way historic Milestone was a decade ago + + + align:start position:0% +Way historic Milestone was a decade ago +with the first flight of quc ferium s53 + + align:start position:0% +with the first flight of quc ferium s53 + + + align:start position:0% +with the first flight of quc ferium s53 +stainless landing gear steel and this + + align:start position:0% +stainless landing gear steel and this + + + align:start position:0% +stainless landing gear steel and this +was the first stainless steel uh to meet + + align:start position:0% +was the first stainless steel uh to meet + + + align:start position:0% +was the first stainless steel uh to meet +the mechanical performance requirements + + align:start position:0% +the mechanical performance requirements + + + align:start position:0% +the mechanical performance requirements +of aircraft landing gear uh which was + + align:start position:0% +of aircraft landing gear uh which was + + + align:start position:0% +of aircraft landing gear uh which was +driven uh by by the need to eliminate uh + + align:start position:0% +driven uh by by the need to eliminate uh + + + align:start position:0% +driven uh by by the need to eliminate uh +toxic cadmium plating so this was a + + align:start position:0% +toxic cadmium plating so this was a + + + align:start position:0% +toxic cadmium plating so this was a +green steel solving an environmental + + align:start position:0% +green steel solving an environmental + + + align:start position:0% +green steel solving an environmental +issue uh but more significant it + + align:start position:0% +issue uh but more significant it + + + align:start position:0% +issue uh but more significant it +represented the first fully + + align:start position:0% +represented the first fully + + + align:start position:0% +represented the first fully +computationally designed and flight + + align:start position:0% +computationally designed and flight + + + align:start position:0% +computationally designed and flight +qualified material to go all the way to + + align:start position:0% +qualified material to go all the way to + + + align:start position:0% +qualified material to go all the way to +flight and that was just in December of + + align:start position:0% +flight and that was just in December of + + + align:start position:0% +flight and that was just in December of +uh 2010 so that really uh measures a + + align:start position:0% +uh 2010 so that really uh measures a + + + align:start position:0% +uh 2010 so that really uh measures a +high level of maturity of this + + align:start position:0% +high level of maturity of this + + + align:start position:0% +high level of maturity of this +technology even before the national MGI + + align:start position:0% +technology even before the national MGI + + + align:start position:0% +technology even before the national MGI +was + + align:start position:0% +was + + + align:start position:0% +was +created and that is reinforced by this + + align:start position:0% +created and that is reinforced by this + + + align:start position:0% +created and that is reinforced by this +timeline so there had been debate as to + + align:start position:0% +timeline so there had been debate as to + + + align:start position:0% +timeline so there had been debate as to +what a material's genome could be it's + + align:start position:0% +what a material's genome could be it's + + + align:start position:0% +what a material's genome could be it's +very clear the genome we have is in fact + + align:start position:0% +very clear the genome we have is in fact + + + align:start position:0% +very clear the genome we have is in fact +the calad database system uh whose + + align:start position:0% +the calad database system uh whose + + + align:start position:0% +the calad database system uh whose +Origins go back to Kaufman and Cohen at + + align:start position:0% +Origins go back to Kaufman and Cohen at + + + align:start position:0% +Origins go back to Kaufman and Cohen at +MIT in the + + align:start position:0% +MIT in the + + + align:start position:0% +MIT in the +1950s uh with a calculation of the iron + + align:start position:0% +1950s uh with a calculation of the iron + + + align:start position:0% +1950s uh with a calculation of the iron +nickel phase + + align:start position:0% +nickel phase + + + align:start position:0% +nickel phase +diagram um like to emphasize though the + + align:start position:0% +diagram um like to emphasize though the + + + align:start position:0% +diagram um like to emphasize though the +the calad + + align:start position:0% +the calad + + + align:start position:0% +the calad +acronym uh is based on calculation of + + align:start position:0% +acronym uh is based on calculation of + + + align:start position:0% +acronym uh is based on calculation of +phase diagrams but uh the reason for + + align:start position:0% +phase diagrams but uh the reason for + + + align:start position:0% +phase diagrams but uh the reason for +that acronym was to distinguish it from + + align:start position:0% +that acronym was to distinguish it from + + + align:start position:0% +that acronym was to distinguish it from +something called f comp at the time uh + + align:start position:0% +something called f comp at the time uh + + + align:start position:0% +something called f comp at the time uh +that was a technique that was trying to + + align:start position:0% +that was a technique that was trying to + + + align:start position:0% +that was a technique that was trying to +estimate uh solubility limits in Alloys + + align:start position:0% +estimate uh solubility limits in Alloys + + + align:start position:0% +estimate uh solubility limits in Alloys +from the attributes of a single phase + + align:start position:0% +from the attributes of a single phase + + + align:start position:0% +from the attributes of a single phase +and calfat acknowledges that solubility + + align:start position:0% +and calfat acknowledges that solubility + + + align:start position:0% +and calfat acknowledges that solubility +is really uh based on phase competition + + align:start position:0% +is really uh based on phase competition + + + align:start position:0% +is really uh based on phase competition +that is uh represented by phase diagrams + + align:start position:0% +that is uh represented by phase diagrams + + + align:start position:0% +that is uh represented by phase diagrams +uh in the equilibrium uh limit uh but in + + align:start position:0% +uh in the equilibrium uh limit uh but in + + + align:start position:0% +uh in the equilibrium uh limit uh but in +fact I think yes can if you don't mind + + align:start position:0% +fact I think yes can if you don't mind + + + align:start position:0% +fact I think yes can if you don't mind +um can you just + + align:start position:0% +um can you just + + + align:start position:0% +um can you just +briefly uh tell us about landing gear + + align:start position:0% +briefly uh tell us about landing gear + + + align:start position:0% +briefly uh tell us about landing gear +and why that's such an accomplishment + + align:start position:0% +and why that's such an accomplishment + + + align:start position:0% +and why that's such an accomplishment +you know I think we take a lot of these + + align:start position:0% +you know I think we take a lot of these + + + align:start position:0% +you know I think we take a lot of these +things for granted you know what what is + + align:start position:0% +things for granted you know what what is + + + align:start position:0% +things for granted you know what what is +it like if there's one one of many + + align:start position:0% +it like if there's one one of many + + + align:start position:0% +it like if there's one one of many +material criteria for instance that that + + align:start position:0% +material criteria for instance that that + + + align:start position:0% +material criteria for instance that that +makes that such a demanding application + + align:start position:0% +makes that such a demanding application + + + align:start position:0% +makes that such a demanding application +so we can understand why that's a big + + align:start position:0% +so we can understand why that's a big + + + align:start position:0% +so we can understand why that's a big +deal yeah I think I'll come back to it a + + align:start position:0% +deal yeah I think I'll come back to it a + + + align:start position:0% +deal yeah I think I'll come back to it a +bit later but but it is the the big + + align:start position:0% +bit later but but it is the the big + + + align:start position:0% +bit later but but it is the the big +challenge is that the high chromium + + align:start position:0% +challenge is that the high chromium + + + align:start position:0% +challenge is that the high chromium +levels that you need uh to get the + + align:start position:0% +levels that you need uh to get the + + + align:start position:0% +levels that you need uh to get the +corrosion resistance are in conflict + + align:start position:0% +corrosion resistance are in conflict + + + align:start position:0% +corrosion resistance are in conflict +with the things you need for the + + align:start position:0% +with the things you need for the + + + align:start position:0% +with the things you need for the +mechanical performance of strength and + + align:start position:0% +mechanical performance of strength and + + + align:start position:0% +mechanical performance of strength and +Fracture toughness and it was a matter + + align:start position:0% +Fracture toughness and it was a matter + + + align:start position:0% +Fracture toughness and it was a matter +of uh using a predictive science + + align:start position:0% +of uh using a predictive science + + + align:start position:0% +of uh using a predictive science +approach uh to take it to a higher level + + align:start position:0% +approach uh to take it to a higher level + + + align:start position:0% +approach uh to take it to a higher level +of optimization that could uh resolve + + align:start position:0% +of optimization that could uh resolve + + + align:start position:0% +of optimization that could uh resolve +that conflict that wasn't going to + + align:start position:0% +that conflict that wasn't going to + + + align:start position:0% +that conflict that wasn't going to +happen by empirical development yeah and + + align:start position:0% +happen by empirical development yeah and + + + align:start position:0% +happen by empirical development yeah and +I'll I'll illustrate what was key to + + align:start position:0% +I'll I'll illustrate what was key to + + + align:start position:0% +I'll I'll illustrate what was key to +that later + + align:start position:0% +that later + + + align:start position:0% +that later +on but I want to emphasize that uh uh + + align:start position:0% +on but I want to emphasize that uh uh + + + align:start position:0% +on but I want to emphasize that uh uh +actually is the name of your class uh + + align:start position:0% +actually is the name of your class uh + + + align:start position:0% +actually is the name of your class uh +materials at equilibrium still is that + + align:start position:0% +materials at equilibrium still is that + + + align:start position:0% +materials at equilibrium still is that +the name that's used no it's + + align:start position:0% +the name that's used no it's + + + align:start position:0% +the name that's used no it's +thermodynamics but it might as well be + + align:start position:0% +thermodynamics but it might as well be + + + align:start position:0% +thermodynamics but it might as well be +material equilibrium okay all right + + align:start position:0% +material equilibrium okay all right + + + align:start position:0% +material equilibrium okay all right +because uh you know we tend to think of + + align:start position:0% +because uh you know we tend to think of + + + align:start position:0% +because uh you know we tend to think of +uh I think the way thermodynamics is + + align:start position:0% +uh I think the way thermodynamics is + + + align:start position:0% +uh I think the way thermodynamics is +thought often we tend to think of it as + + align:start position:0% +thought often we tend to think of it as + + + align:start position:0% +thought often we tend to think of it as +something that applies only to + + align:start position:0% +something that applies only to + + + align:start position:0% +something that applies only to +equilibrium but but the truth is + + align:start position:0% +equilibrium but but the truth is + + + align:start position:0% +equilibrium but but the truth is +wouldn't be called thermodynamics if it + + align:start position:0% +wouldn't be called thermodynamics if it + + + align:start position:0% +wouldn't be called thermodynamics if it +was only about equilibrium it was + + align:start position:0% +was only about equilibrium it was + + + align:start position:0% +was only about equilibrium it was +created to describe heat engines that + + align:start position:0% +created to describe heat engines that + + + align:start position:0% +created to describe heat engines that +are highly Dynamic systems where in + + align:start position:0% +are highly Dynamic systems where in + + + align:start position:0% +are highly Dynamic systems where in +modeling them it was useful to look at + + align:start position:0% +modeling them it was useful to look at + + + align:start position:0% +modeling them it was useful to look at +equilibrium limits it's also very useful + + align:start position:0% +equilibrium limits it's also very useful + + + align:start position:0% +equilibrium limits it's also very useful +if you want to measure thermodynamics we + + align:start position:0% +if you want to measure thermodynamics we + + + align:start position:0% +if you want to measure thermodynamics we +should take systems to equilibrium so we + + align:start position:0% +should take systems to equilibrium so we + + + align:start position:0% +should take systems to equilibrium so we +know what we're measuring but really the + + align:start position:0% +know what we're measuring but really the + + + align:start position:0% +know what we're measuring but really the +power of of thermodynamics is it + + align:start position:0% +power of of thermodynamics is it + + + align:start position:0% +power of of thermodynamics is it +describes the driving force of dynamic + + align:start position:0% +describes the driving force of dynamic + + + align:start position:0% +describes the driving force of dynamic +systems and it really drives the + + align:start position:0% +systems and it really drives the + + + align:start position:0% +systems and it really drives the +evolution of microstructures and + + align:start position:0% +evolution of microstructures and + + + align:start position:0% +evolution of microstructures and +processing and and service so uh it + + align:start position:0% +processing and and service so uh it + + + align:start position:0% +processing and and service so uh it +really is in that sense the genomic data + + align:start position:0% +really is in that sense the genomic data + + + align:start position:0% +really is in that sense the genomic data +that drives the + + align:start position:0% +that drives the + + + align:start position:0% +that drives the +systems so in fact uh I prefer to uh + + align:start position:0% +systems so in fact uh I prefer to uh + + + align:start position:0% +systems so in fact uh I prefer to uh +describe calad as calculated phase + + align:start position:0% +describe calad as calculated phase + + + align:start position:0% +describe calad as calculated phase +Dynamics and so it starts with + + align:start position:0% +Dynamics and so it starts with + + + align:start position:0% +Dynamics and so it starts with +thermodynamics uh but its real Power + + align:start position:0% +thermodynamics uh but its real Power + + + align:start position:0% +thermodynamics uh but its real Power +Systems far from equilibrium and in fact + + align:start position:0% +Systems far from equilibrium and in fact + + + align:start position:0% +Systems far from equilibrium and in fact +uh when it was invented by Kaufman and + + align:start position:0% +uh when it was invented by Kaufman and + + + align:start position:0% +uh when it was invented by Kaufman and +Cohen uh what they were really trying to + + align:start position:0% +Cohen uh what they were really trying to + + + align:start position:0% +Cohen uh what they were really trying to +do was not uh to calculate a phase + + align:start position:0% +do was not uh to calculate a phase + + + align:start position:0% +do was not uh to calculate a phase +diagram they were trying to take the + + align:start position:0% +diagram they were trying to take the + + + align:start position:0% +diagram they were trying to take the +information that's there in an + + align:start position:0% +information that's there in an + + + align:start position:0% +information that's there in an +equilibrium diagram and reduce it to its + + align:start position:0% +equilibrium diagram and reduce it to its + + + align:start position:0% +equilibrium diagram and reduce it to its +underlying Thermon namics so they could + + align:start position:0% +underlying Thermon namics so they could + + + align:start position:0% +underlying Thermon namics so they could +apply that theramic to Martin cidic + + align:start position:0% +apply that theramic to Martin cidic + + + align:start position:0% +apply that theramic to Martin cidic +Transformations that are far from + + align:start position:0% +Transformations that are far from + + + align:start position:0% +Transformations that are far from +equilibrium so it was really to create + + align:start position:0% +equilibrium so it was really to create + + + align:start position:0% +equilibrium so it was really to create +the get the underlying Thermon namics uh + + align:start position:0% +the get the underlying Thermon namics uh + + + align:start position:0% +the get the underlying Thermon namics uh +to understand the driving forces for the + + align:start position:0% +to understand the driving forces for the + + + align:start position:0% +to understand the driving forces for the +Dynamics of Martin City Transformations + + align:start position:0% +Dynamics of Martin City Transformations + + + align:start position:0% +Dynamics of Martin City Transformations +so it really is the non-equilibrium + + align:start position:0% +so it really is the non-equilibrium + + + align:start position:0% +so it really is the non-equilibrium +applications that drove the creation of + + align:start position:0% +applications that drove the creation of + + + align:start position:0% +applications that drove the creation of +the technology in the first place so it + + align:start position:0% +the technology in the first place so it + + + align:start position:0% +the technology in the first place so it +began uh as solution Thermon namics + + align:start position:0% +began uh as solution Thermon namics + + + align:start position:0% +began uh as solution Thermon namics +uh and uh became an international + + align:start position:0% +uh and uh became an international + + + align:start position:0% +uh and uh became an international +organization in the + + align:start position:0% +organization in the + + + align:start position:0% +organization in the +1970s uh and the first commercial + + align:start position:0% +1970s uh and the first commercial + + + align:start position:0% +1970s uh and the first commercial +software showed up around the + + align:start position:0% +software showed up around the + + + align:start position:0% +software showed up around the +1980s uh but then it expanded from + + align:start position:0% +1980s uh but then it expanded from + + + align:start position:0% +1980s uh but then it expanded from +solution Thermon namics to adding + + align:start position:0% +solution Thermon namics to adding + + + align:start position:0% +solution Thermon namics to adding +Mobility databases and solving + + align:start position:0% +Mobility databases and solving + + + align:start position:0% +Mobility databases and solving +multicomponent diffusion problems moving + + align:start position:0% +multicomponent diffusion problems moving + + + align:start position:0% +multicomponent diffusion problems moving +on to other phase level attributes such + + align:start position:0% +on to other phase level attributes such + + + align:start position:0% +on to other phase level attributes such +as elastic uh constants uh so an + + align:start position:0% +as elastic uh constants uh so an + + + align:start position:0% +as elastic uh constants uh so an +increasing array of phase level uh + + align:start position:0% +increasing array of phase level uh + + + align:start position:0% +increasing array of phase level uh +theramic and kinetic attributes uh over + + align:start position:0% +theramic and kinetic attributes uh over + + + align:start position:0% +theramic and kinetic attributes uh over +an expanding scope of materials from + + align:start position:0% +an expanding scope of materials from + + + align:start position:0% +an expanding scope of materials from +metals to Ceramics and very recently + + align:start position:0% +metals to Ceramics and very recently + + + align:start position:0% +metals to Ceramics and very recently +organic systems as well uh all of which + + align:start position:0% +organic systems as well uh all of which + + + align:start position:0% +organic systems as well uh all of which +was largely based on empirical + + align:start position:0% +was largely based on empirical + + + align:start position:0% +was largely based on empirical +measurement uh but today uh DFT physics + + align:start position:0% +measurement uh but today uh DFT physics + + + align:start position:0% +measurement uh but today uh DFT physics +calculations uh received enough uh + + align:start position:0% +calculations uh received enough uh + + + align:start position:0% +calculations uh received enough uh +accuracy and efficiency that they now + + align:start position:0% +accuracy and efficiency that they now + + + align:start position:0% +accuracy and efficiency that they now +actually actively participate and we + + align:start position:0% +actually actively participate and we + + + align:start position:0% +actually actively participate and we +integrate into the assessment of these + + align:start position:0% +integrate into the assessment of these + + + align:start position:0% +integrate into the assessment of these +databases uh the predictions from uh + + align:start position:0% +databases uh the predictions from uh + + + align:start position:0% +databases uh the predictions from uh +physics calculations at least for zero + + align:start position:0% +physics calculations at least for zero + + + align:start position:0% +physics calculations at least for zero +Kelvin enthalpy + + align:start position:0% +Kelvin enthalpy + + + align:start position:0% +Kelvin enthalpy +predictions uh so it was the uh arrival + + align:start position:0% +predictions uh so it was the uh arrival + + + align:start position:0% +predictions uh so it was the uh arrival +of the thermocalc system as a commercial + + align:start position:0% +of the thermocalc system as a commercial + + + align:start position:0% +of the thermocalc system as a commercial +code uh and a supporting uh software uh + + align:start position:0% +code uh and a supporting uh software uh + + + align:start position:0% +code uh and a supporting uh software uh +database structure uh set by the + + align:start position:0% +database structure uh set by the + + + align:start position:0% +database structure uh set by the +European sgte Consortium that set some + + align:start position:0% +European sgte Consortium that set some + + + align:start position:0% +European sgte Consortium that set some +level of + + align:start position:0% +level of + + + align:start position:0% +level of +standardization uh that really inspired + + align:start position:0% +standardization uh that really inspired + + + align:start position:0% +standardization uh that really inspired +our founding in + + align:start position:0% +our founding in + + + align:start position:0% +our founding in +1985 of our srg uh design Consortium and + + align:start position:0% +1985 of our srg uh design Consortium and + + + align:start position:0% +1985 of our srg uh design Consortium and +this was founded at MIT + + align:start position:0% +this was founded at MIT + + + align:start position:0% +this was founded at MIT +uh and the idea was uh to create a + + align:start position:0% +uh and the idea was uh to create a + + + align:start position:0% +uh and the idea was uh to create a +general methodology of computational + + align:start position:0% +general methodology of computational + + + align:start position:0% +general methodology of computational +materials design that would be enabled + + align:start position:0% +materials design that would be enabled + + + align:start position:0% +materials design that would be enabled +by these underlying calad + + align:start position:0% +by these underlying calad + + + align:start position:0% +by these underlying calad +databases uh with the idea that we would + + align:start position:0% +databases uh with the idea that we would + + + align:start position:0% +databases uh with the idea that we would +use high performance Steels as the first + + align:start position:0% +use high performance Steels as the first + + + align:start position:0% +use high performance Steels as the first +example acknowledging that we studied + + align:start position:0% +example acknowledging that we studied + + + align:start position:0% +example acknowledging that we studied +Steels the longest have the deepest + + align:start position:0% +Steels the longest have the deepest + + + align:start position:0% +Steels the longest have the deepest +predictive Science Foundation in steel + + align:start position:0% +predictive Science Foundation in steel + + + align:start position:0% +predictive Science Foundation in steel +and also at that point the highest + + align:start position:0% +and also at that point the highest + + + align:start position:0% +and also at that point the highest +quality of theramic data was available + + align:start position:0% +quality of theramic data was available + + + align:start position:0% +quality of theramic data was available +for Steels to use that as the + + align:start position:0% +for Steels to use that as the + + + align:start position:0% +for Steels to use that as the +demonstrator so our first projects were + + align:start position:0% +demonstrator so our first projects were + + + align:start position:0% +demonstrator so our first projects were +designs of Steels but throughout the + + align:start position:0% +designs of Steels but throughout the + + + align:start position:0% +designs of Steels but throughout the +1990s uh we did uh a number of demo + + align:start position:0% +1990s uh we did uh a number of demo + + + align:start position:0% +1990s uh we did uh a number of demo +projects that applied the same + + align:start position:0% +projects that applied the same + + + align:start position:0% +projects that applied the same +methodology to other alloy systems + + align:start position:0% +methodology to other alloy systems + + + align:start position:0% +methodology to other alloy systems +polymer Ceramics and even some composits + + align:start position:0% +polymer Ceramics and even some composits + + + align:start position:0% +polymer Ceramics and even some composits +to show its generality and it was the + + align:start position:0% +to show its generality and it was the + + + align:start position:0% +to show its generality and it was the +first steel designs that ultimately led + + align:start position:0% +first steel designs that ultimately led + + + align:start position:0% +first steel designs that ultimately led +to the founding in the late + + align:start position:0% +to the founding in the late + + + align:start position:0% +to the founding in the late +1990s of questec as a company that could + + align:start position:0% +1990s of questec as a company that could + + + align:start position:0% +1990s of questec as a company that could +offer uh computational Design Services + + align:start position:0% +offer uh computational Design Services + + + align:start position:0% +offer uh computational Design Services +based on this technology but what the + + align:start position:0% +based on this technology but what the + + + align:start position:0% +based on this technology but what the +calat is really allowing us to do is is + + align:start position:0% +calat is really allowing us to do is is + + + align:start position:0% +calat is really allowing us to do is is +use this mechanistic understanding we + + align:start position:0% +use this mechanistic understanding we + + + align:start position:0% +use this mechanistic understanding we +already possess but use it in a + + align:start position:0% +already possess but use it in a + + + align:start position:0% +already possess but use it in a +quantitative system specific + + align:start position:0% +quantitative system specific + + + align:start position:0% +quantitative system specific +way and that's what enabled the the + + align:start position:0% +way and that's what enabled the the + + + align:start position:0% +way and that's what enabled the the +successful demonstrations of design of + + align:start position:0% +successful demonstrations of design of + + + align:start position:0% +successful demonstrations of design of +new materials throughout the + + align:start position:0% +new materials throughout the + + + align:start position:0% +new materials throughout the +1990s uh and it was largely that + + align:start position:0% +1990s uh and it was largely that + + + align:start position:0% +1990s uh and it was largely that +demonstrated success that made the case + + align:start position:0% +demonstrated success that made the case + + + align:start position:0% +demonstrated success that made the case +uh for the DARPA aim in initiative which + + align:start position:0% +uh for the DARPA aim in initiative which + + + align:start position:0% +uh for the DARPA aim in initiative which +began at the start of the the New + + align:start position:0% +began at the start of the the New + + + align:start position:0% +began at the start of the the New +Millennium uh and this was really + + align:start position:0% +Millennium uh and this was really + + + align:start position:0% +Millennium uh and this was really +addressing uh the central focus of what + + align:start position:0% +addressing uh the central focus of what + + + align:start position:0% +addressing uh the central focus of what +is now the MGI and what we now call + + align:start position:0% +is now the MGI and what we now call + + + align:start position:0% +is now the MGI and what we now call +Integrated computational materials + + align:start position:0% +Integrated computational materials + + + align:start position:0% +Integrated computational materials +engineering or mcme and this was to go + + align:start position:0% +engineering or mcme and this was to go + + + align:start position:0% +engineering or mcme and this was to go +beyond the design of an alloy and SP set + + align:start position:0% +beyond the design of an alloy and SP set + + + align:start position:0% +beyond the design of an alloy and SP set +a + + align:start position:0% +a + + + align:start position:0% +a +specification of composition and process + + align:start position:0% +specification of composition and process + + + align:start position:0% +specification of composition and process +temperatures uh to really address the + + align:start position:0% +temperatures uh to really address the + + + align:start position:0% +temperatures uh to really address the +full materials development cycle uh and + + align:start position:0% +full materials development cycle uh and + + + align:start position:0% +full materials development cycle uh and +this meant uh connecting materials + + align:start position:0% +this meant uh connecting materials + + + align:start position:0% +this meant uh connecting materials +models to macroscopic process models uh + + align:start position:0% +models to macroscopic process models uh + + + align:start position:0% +models to macroscopic process models uh +to handle uh material production scaleup + + align:start position:0% +to handle uh material production scaleup + + + align:start position:0% +to handle uh material production scaleup +uh uh process optimization at the + + align:start position:0% +uh uh process optimization at the + + + align:start position:0% +uh uh process optimization at the +component level of things like landing + + align:start position:0% +component level of things like landing + + + align:start position:0% +component level of things like landing +gear uh and then most important uh the + + align:start position:0% +gear uh and then most important uh the + + + align:start position:0% +gear uh and then most important uh the +forecast of manufacturing variation so + + align:start position:0% +forecast of manufacturing variation so + + + align:start position:0% +forecast of manufacturing variation so +that you could predict the minimum + + align:start position:0% +that you could predict the minimum + + + align:start position:0% +that you could predict the minimum +properties of a material that uh are + + align:start position:0% +properties of a material that uh are + + + align:start position:0% +properties of a material that uh are +user could count on at a 1% probability + + align:start position:0% +user could count on at a 1% probability + + + align:start position:0% +user could count on at a 1% probability +basis and that's what it takes uh to get + + align:start position:0% +basis and that's what it takes uh to get + + + align:start position:0% +basis and that's what it takes uh to get +a material actually flight qualified for + + align:start position:0% +a material actually flight qualified for + + + align:start position:0% +a material actually flight qualified for +critical applications so at this point + + align:start position:0% +critical applications so at this point + + + align:start position:0% +critical applications so at this point +we've had over six Decades of building + + align:start position:0% +we've had over six Decades of building + + + align:start position:0% +we've had over six Decades of building +out a material's genome with calad + + align:start position:0% +out a material's genome with calad + + + align:start position:0% +out a material's genome with calad +structure uh about 30 years now of uh uh + + align:start position:0% +structure uh about 30 years now of uh uh + + + align:start position:0% +structure uh about 30 years now of uh uh +a full design technology and we've now + + align:start position:0% +a full design technology and we've now + + + align:start position:0% +a full design technology and we've now +been at 20 years of a fully integrated + + align:start position:0% +been at 20 years of a fully integrated + + + align:start position:0% +been at 20 years of a fully integrated +uh process so it's quite uh uh developed + + align:start position:0% +uh process so it's quite uh uh developed + + + align:start position:0% +uh process so it's quite uh uh developed +and as I'll touch on later on uh what + + align:start position:0% +and as I'll touch on later on uh what + + + align:start position:0% +and as I'll touch on later on uh what +this has allowed the compression of the + + align:start position:0% +this has allowed the compression of the + + + align:start position:0% +this has allowed the compression of the +materials developed vment cycle uh + + align:start position:0% +materials developed vment cycle uh + + + align:start position:0% +materials developed vment cycle uh +getting it down to the cycle of product + + align:start position:0% +getting it down to the cycle of product + + + align:start position:0% +getting it down to the cycle of product +development has allowed for the first + + align:start position:0% +development has allowed for the first + + + align:start position:0% +development has allowed for the first +time uh to include materials in + + align:start position:0% +time uh to include materials in + + + align:start position:0% +time uh to include materials in +concurrent engineering historically + + align:start position:0% +concurrent engineering historically + + + align:start position:0% +concurrent engineering historically +concurrent engineering meant everything + + align:start position:0% +concurrent engineering meant everything + + + align:start position:0% +concurrent engineering meant everything +but materials you had to use whatever + + align:start position:0% +but materials you had to use whatever + + + align:start position:0% +but materials you had to use whatever +materials were available uh and now + + align:start position:0% +materials were available uh and now + + + align:start position:0% +materials were available uh and now +there are a number of success stories + + align:start position:0% +there are a number of success stories + + + align:start position:0% +there are a number of success stories +I'll touch on later where materials have + + align:start position:0% +I'll touch on later where materials have + + + align:start position:0% +I'll touch on later where materials have +been fully integrated in concurrency and + + align:start position:0% +been fully integrated in concurrency and + + + align:start position:0% +been fully integrated in concurrency and +and uh allowing a very strong Synergy + + align:start position:0% +and uh allowing a very strong Synergy + + + align:start position:0% +and uh allowing a very strong Synergy +between materials development and + + align:start position:0% +between materials development and + + + align:start position:0% +between materials development and +product + + align:start position:0% +product + + + align:start position:0% +product +development so that's the + + align:start position:0% + + + + align:start position:0% + +landscape core of our approach uh is the + + align:start position:0% +landscape core of our approach uh is the + + + align:start position:0% +landscape core of our approach uh is the +philosophy of the late great serial + + align:start position:0% +philosophy of the late great serial + + + align:start position:0% +philosophy of the late great serial +Stanley Smith of + + align:start position:0% +Stanley Smith of + + + align:start position:0% +Stanley Smith of +MIT uh who uh looked at the general + + align:start position:0% +MIT uh who uh looked at the general + + + align:start position:0% +MIT uh who uh looked at the general +principles of dynamic interactive + + align:start position:0% +principles of dynamic interactive + + + align:start position:0% +principles of dynamic interactive +multi-level structure or structure + + align:start position:0% +multi-level structure or structure + + + align:start position:0% +multi-level structure or structure +hierarchy uh and acknowledge an + + align:start position:0% +hierarchy uh and acknowledge an + + + align:start position:0% +hierarchy uh and acknowledge an +intrinsic complexity of material + + align:start position:0% +intrinsic complexity of material + + + align:start position:0% +intrinsic complexity of material +structure uh for which he advocated that + + align:start position:0% +structure uh for which he advocated that + + + align:start position:0% +structure uh for which he advocated that +we should be taking a systems approach + + align:start position:0% +we should be taking a systems approach + + + align:start position:0% +we should be taking a systems approach +and essentially using the same framework + + align:start position:0% +and essentially using the same framework + + + align:start position:0% +and essentially using the same framework +of systems engineering uh that the rest + + align:start position:0% +of systems engineering uh that the rest + + + align:start position:0% +of systems engineering uh that the rest +of engineering is already using uh so + + align:start position:0% +of engineering is already using uh so + + + align:start position:0% +of engineering is already using uh so +we've taken that to heart uh and to + + align:start position:0% +we've taken that to heart uh and to + + + align:start position:0% +we've taken that to heart uh and to +implement it another important + + align:start position:0% +implement it another important + + + align:start position:0% +implement it another important +contribution from the late great Morris + + align:start position:0% +contribution from the late great Morris + + + align:start position:0% +contribution from the late great Morris +Cohen of MIT is what he described as a + + align:start position:0% +Cohen of MIT is what he described as a + + + align:start position:0% +Cohen of MIT is what he described as a +reciprocity between the opposite + + align:start position:0% +reciprocity between the opposite + + + align:start position:0% +reciprocity between the opposite +philosophies of Science and Engineering + + align:start position:0% +philosophies of Science and Engineering + + + align:start position:0% +philosophies of Science and Engineering +that are represented by this unique + + align:start position:0% +that are represented by this unique + + + align:start position:0% +that are represented by this unique +linear structure in which the predictive + + align:start position:0% +linear structure in which the predictive + + + align:start position:0% +linear structure in which the predictive +cause and effect logic of science flows + + align:start position:0% +cause and effect logic of science flows + + + align:start position:0% +cause and effect logic of science flows +from left to right + + align:start position:0% +from left to right + + + align:start position:0% +from left to right +and the inductive goals means uh logic + + align:start position:0% +and the inductive goals means uh logic + + + align:start position:0% +and the inductive goals means uh logic +of engineering flows from right to left + + align:start position:0% +of engineering flows from right to left + + + align:start position:0% +of engineering flows from right to left +so it actually allows us to bring these + + align:start position:0% +so it actually allows us to bring these + + + align:start position:0% +so it actually allows us to bring these +two philosophies together in a + + align:start position:0% +two philosophies together in a + + + align:start position:0% +two philosophies together in a +streamlined non-turbulent way so the uh + + align:start position:0% +streamlined non-turbulent way so the uh + + + align:start position:0% +streamlined non-turbulent way so the uh +scientific prediction is that uh however + + align:start position:0% +scientific prediction is that uh however + + + align:start position:0% +scientific prediction is that uh however +we process a material we determine its + + align:start position:0% +we process a material we determine its + + + align:start position:0% +we process a material we determine its +structure the structure will determine + + align:start position:0% +structure the structure will determine + + + align:start position:0% +structure the structure will determine +the properties and the combination of + + align:start position:0% +the properties and the combination of + + + align:start position:0% +the properties and the combination of +properties will determine its + + align:start position:0% +properties will determine its + + + align:start position:0% +properties will determine its +performance uh and this then enables a + + align:start position:0% +performance uh and this then enables a + + + align:start position:0% +performance uh and this then enables a +design system where we can set + + align:start position:0% +design system where we can set + + + align:start position:0% +design system where we can set +performance goals for a new material + + align:start position:0% +performance goals for a new material + + + align:start position:0% +performance goals for a new material +that we map to a set of property + + align:start position:0% +that we map to a set of property + + + align:start position:0% +that we map to a set of property +objectives uh use our knowledge of + + align:start position:0% +objectives uh use our knowledge of + + + align:start position:0% +objectives uh use our knowledge of +structure property relations to devise + + align:start position:0% +structure property relations to devise + + + align:start position:0% +structure property relations to devise +possible micr structures that are + + align:start position:0% +possible micr structures that are + + + align:start position:0% +possible micr structures that are +accessible through prescribed uh + + align:start position:0% +accessible through prescribed uh + + + align:start position:0% +accessible through prescribed uh +processing it's important to know that + + align:start position:0% +processing it's important to know that + + + align:start position:0% +processing it's important to know that +the the flow from left to right is + + align:start position:0% +the the flow from left to right is + + + align:start position:0% +the the flow from left to right is +unique that exactly how we process will + + align:start position:0% +unique that exactly how we process will + + + align:start position:0% +unique that exactly how we process will +determine that structure and a unique + + align:start position:0% +determine that structure and a unique + + + align:start position:0% +determine that structure and a unique +set of properties and performance uh + + align:start position:0% +set of properties and performance uh + + + align:start position:0% +set of properties and performance uh +it's always the nature of this inverse + + align:start position:0% +it's always the nature of this inverse + + + align:start position:0% +it's always the nature of this inverse +problem that we do not have uniqueness + + align:start position:0% +problem that we do not have uniqueness + + + align:start position:0% +problem that we do not have uniqueness +that once we have a set of property + + align:start position:0% +that once we have a set of property + + + align:start position:0% +that once we have a set of property +objectives there are multiple structures + + align:start position:0% +objectives there are multiple structures + + + align:start position:0% +objectives there are multiple structures +and multiple processed Pathways uh that + + align:start position:0% +and multiple processed Pathways uh that + + + align:start position:0% +and multiple processed Pathways uh that +we could use to to achieve that uh so + + align:start position:0% +we could use to to achieve that uh so + + + align:start position:0% +we could use to to achieve that uh so +the approach uh in in adopting a system + + align:start position:0% +the approach uh in in adopting a system + + + align:start position:0% +the approach uh in in adopting a system +framework is to use this as the backbone + + align:start position:0% +framework is to use this as the backbone + + + align:start position:0% +framework is to use this as the backbone +of a system structure and add Smith + + align:start position:0% +of a system structure and add Smith + + + align:start position:0% +of a system structure and add Smith +structural hierarchy to it so the each + + align:start position:0% +structural hierarchy to it so the each + + + align:start position:0% +structural hierarchy to it so the each +design project starts with a system + + align:start position:0% +design project starts with a system + + + align:start position:0% +design project starts with a system +chart uh and the idea here uh is to get + + align:start position:0% +chart uh and the idea here uh is to get + + + align:start position:0% +chart uh and the idea here uh is to get +the entire material down on a page uh so + + align:start position:0% +the entire material down on a page uh so + + + align:start position:0% +the entire material down on a page uh so +the left to right flow of this is the + + align:start position:0% +the left to right flow of this is the + + + align:start position:0% +the left to right flow of this is the +cause and effect logic but the process + + align:start position:0% +cause and effect logic but the process + + + align:start position:0% +cause and effect logic but the process +of design uh Works uh from from right to + + align:start position:0% +of design uh Works uh from from right to + + + align:start position:0% +of design uh Works uh from from right to +left uh where performance uh goals + + align:start position:0% +left uh where performance uh goals + + + align:start position:0% +left uh where performance uh goals +overall will be mapped to a quantitative + + align:start position:0% +overall will be mapped to a quantitative + + + align:start position:0% +overall will be mapped to a quantitative +set of properties such as strength + + align:start position:0% +set of properties such as strength + + + align:start position:0% +set of properties such as strength +toughness for a high performance steel + + align:start position:0% +toughness for a high performance steel + + + align:start position:0% +toughness for a high performance steel +uh and resistance to environmental + + align:start position:0% +uh and resistance to environmental + + + align:start position:0% +uh and resistance to environmental +hydrogen + + align:start position:0% +hydrogen + + + align:start position:0% +hydrogen +embrittlement and from our mechanistic + + align:start position:0% +embrittlement and from our mechanistic + + + align:start position:0% +embrittlement and from our mechanistic +knowledge we know that those properties + + align:start position:0% +knowledge we know that those properties + + + align:start position:0% +knowledge we know that those properties +map back to different subsystems in the + + align:start position:0% +map back to different subsystems in the + + + align:start position:0% +map back to different subsystems in the +hierarchy of microstructural subsystems + + align:start position:0% +hierarchy of microstructural subsystems + + + align:start position:0% +hierarchy of microstructural subsystems +which we know dynamically evolve + + align:start position:0% +which we know dynamically evolve + + + align:start position:0% +which we know dynamically evolve +throughout the stages of materials uh + + align:start position:0% +throughout the stages of materials uh + + + align:start position:0% +throughout the stages of materials uh +processing and that allows us to then + + align:start position:0% +processing and that allows us to then + + + align:start position:0% +processing and that allows us to then +identify and prioritize the key + + align:start position:0% +identify and prioritize the key + + + align:start position:0% +identify and prioritize the key +structure property links and process + + align:start position:0% +structure property links and process + + + align:start position:0% +structure property links and process +structure links for which we want to + + align:start position:0% +structure links for which we want to + + + align:start position:0% +structure links for which we want to +build out our uh design + + align:start position:0% +build out our uh design + + + align:start position:0% +build out our uh design +models uh now that can be done by uh + + align:start position:0% +models uh now that can be done by uh + + + align:start position:0% +models uh now that can be done by uh +empirical correlations that are useful + + align:start position:0% +empirical correlations that are useful + + + align:start position:0% +empirical correlations that are useful +for + + align:start position:0% +for + + + align:start position:0% +for +interpolation uh but we really uh from + + align:start position:0% +interpolation uh but we really uh from + + + align:start position:0% +interpolation uh but we really uh from +from the start we're committed to uh by + + align:start position:0% +from the start we're committed to uh by + + + align:start position:0% +from the start we're committed to uh by +getting the most value out of the calad + + align:start position:0% +getting the most value out of the calad + + + align:start position:0% +getting the most value out of the calad +fundamental data is to use uh predictive + + align:start position:0% +fundamental data is to use uh predictive + + + align:start position:0% +fundamental data is to use uh predictive +science based on mechanistic + + align:start position:0% +science based on mechanistic + + + align:start position:0% +science based on mechanistic +understanding and to express that + + align:start position:0% +understanding and to express that + + + align:start position:0% +understanding and to express that +mechanistic under form that we could + + align:start position:0% +mechanistic under form that we could + + + align:start position:0% +mechanistic under form that we could +parameterize to make uh devise + + align:start position:0% +parameterize to make uh devise + + + align:start position:0% +parameterize to make uh devise +parameters accessible uh to those + + align:start position:0% +parameters accessible uh to those + + + align:start position:0% +parameters accessible uh to those +fundamental + + align:start position:0% +fundamental + + + align:start position:0% +fundamental +databases uh to make uh a quantitative + + align:start position:0% +databases uh to make uh a quantitative + + + align:start position:0% +databases uh to make uh a quantitative +approach to the full design of the + + align:start position:0% +approach to the full design of the + + + align:start position:0% +approach to the full design of the +material that produces different levels + + align:start position:0% +material that produces different levels + + + align:start position:0% +material that produces different levels +of of microstructure throughout + + align:start position:0% +of of microstructure throughout + + + align:start position:0% +of of microstructure throughout +different stages of processing uh and + + align:start position:0% +different stages of processing uh and + + + align:start position:0% +different stages of processing uh and +meets all those uh uh property + + align:start position:0% +meets all those uh uh property + + + align:start position:0% +meets all those uh uh property +requirements for useful + + align:start position:0% +requirements for useful + + + align:start position:0% +requirements for useful +material and what that + + align:start position:0% +material and what that + + + align:start position:0% +material and what that +motivated uh was the models summarized + + align:start position:0% +motivated uh was the models summarized + + + align:start position:0% +motivated uh was the models summarized +here which really is a a subset of + + align:start position:0% +here which really is a a subset of + + + align:start position:0% +here which really is a a subset of +what's available in computational + + align:start position:0% +what's available in computational + + + align:start position:0% +what's available in computational +Material Science that that allowed us to + + align:start position:0% +Material Science that that allowed us to + + + align:start position:0% +Material Science that that allowed us to +do uh quantitative engineering uh so at + + align:start position:0% +do uh quantitative engineering uh so at + + + align:start position:0% +do uh quantitative engineering uh so at +the bottom uh level uh the three fields + + align:start position:0% +the bottom uh level uh the three fields + + + align:start position:0% +the bottom uh level uh the three fields +we uh integrated where the DFT physics + + align:start position:0% +we uh integrated where the DFT physics + + + align:start position:0% +we uh integrated where the DFT physics +that was particularly useful for surface + + align:start position:0% +that was particularly useful for surface + + + align:start position:0% +that was particularly useful for surface +Thermon namics which is more difficult + + align:start position:0% +Thermon namics which is more difficult + + + align:start position:0% +Thermon namics which is more difficult +to measure than bulk Thermon namics and + + align:start position:0% +to measure than bulk Thermon namics and + + + align:start position:0% +to measure than bulk Thermon namics and +of course uh the material science is is + + align:start position:0% +of course uh the material science is is + + + align:start position:0% +of course uh the material science is is +uh particularly advanced in the theory + + align:start position:0% +uh particularly advanced in the theory + + + align:start position:0% +uh particularly advanced in the theory +of uh solid state precipitation and + + align:start position:0% +of uh solid state precipitation and + + + align:start position:0% +of uh solid state precipitation and +precipitation + + align:start position:0% +precipitation + + + align:start position:0% +precipitation +strengthening uh and for structure + + align:start position:0% +strengthening uh and for structure + + + align:start position:0% +strengthening uh and for structure +property relations uh we applied uh + + align:start position:0% +property relations uh we applied uh + + + align:start position:0% +property relations uh we applied uh +brought in the micromechanical + + align:start position:0% +brought in the micromechanical + + + align:start position:0% +brought in the micromechanical +applications of Continuum mechanics uh + + align:start position:0% +applications of Continuum mechanics uh + + + align:start position:0% +applications of Continuum mechanics uh +to simulate unit process of fracture and + + align:start position:0% +to simulate unit process of fracture and + + + align:start position:0% +to simulate unit process of fracture and +fatigue to set the structure property + + align:start position:0% +fatigue to set the structure property + + + align:start position:0% +fatigue to set the structure property +relations so these are really uh the + + align:start position:0% +relations so these are really uh the + + + align:start position:0% +relations so these are really uh the +three disciplines that were integrated + + align:start position:0% +three disciplines that were integrated + + + align:start position:0% +three disciplines that were integrated +in this approach uh for to meet + + align:start position:0% +in this approach uh for to meet + + + align:start position:0% +in this approach uh for to meet +performance goals but equally important + + align:start position:0% +performance goals but equally important + + + align:start position:0% +performance goals but equally important +is to constrain the processibility of a + + align:start position:0% +is to constrain the processibility of a + + + align:start position:0% +is to constrain the processibility of a +material and that's a role for the M + + align:start position:0% +material and that's a role for the M + + + align:start position:0% +material and that's a role for the M +calad based Material Science models of + + align:start position:0% +calad based Material Science models of + + + align:start position:0% +calad based Material Science models of +the solid solid phase Transformations + + align:start position:0% +the solid solid phase Transformations + + + align:start position:0% +the solid solid phase Transformations +and the liquid solid phase + + align:start position:0% +and the liquid solid phase + + + align:start position:0% +and the liquid solid phase +Transformations uh both of we which are + + align:start position:0% +Transformations uh both of we which are + + + align:start position:0% +Transformations uh both of we which are +uh scaled dependent in terms of the size + + align:start position:0% +uh scaled dependent in terms of the size + + + align:start position:0% +uh scaled dependent in terms of the size +of heat treated components uh through + + align:start position:0% +of heat treated components uh through + + + align:start position:0% +of heat treated components uh through +the size dependence of heat transfer uh + + align:start position:0% +the size dependence of heat transfer uh + + + align:start position:0% +the size dependence of heat transfer uh +so ultimately it's the linking of of + + align:start position:0% +so ultimately it's the linking of of + + + align:start position:0% +so ultimately it's the linking of of +these micr structural models to the + + align:start position:0% +these micr structural models to the + + + align:start position:0% +these micr structural models to the +macroscopic process simulations uh that + + align:start position:0% +macroscopic process simulations uh that + + + align:start position:0% +macroscopic process simulations uh that +allow us to constrain materials up front + + align:start position:0% +allow us to constrain materials up front + + + align:start position:0% +allow us to constrain materials up front +theoretically to be processable on a + + align:start position:0% +theoretically to be processable on a + + + align:start position:0% +theoretically to be processable on a +design on a desired scale uh and that + + align:start position:0% +design on a desired scale uh and that + + + align:start position:0% +design on a desired scale uh and that +really uh helps to accelerate the full + + align:start position:0% +really uh helps to accelerate the full + + + align:start position:0% +really uh helps to accelerate the full +cycle uh instead of experimental scaleup + + align:start position:0% +cycle uh instead of experimental scaleup + + + align:start position:0% +cycle uh instead of experimental scaleup +uh so what's represented here on the + + align:start position:0% +uh so what's represented here on the + + + align:start position:0% +uh so what's represented here on the +right are the software models and their + + align:start position:0% +right are the software models and their + + + align:start position:0% +right are the software models and their +uh their their platforms uh and the + + align:start position:0% +uh their their platforms uh and the + + + align:start position:0% +uh their their platforms uh and the +advanced instrumentation is equally + + align:start position:0% +advanced instrumentation is equally + + + align:start position:0% +advanced instrumentation is equally +important the ability to use techniques + + align:start position:0% +important the ability to use techniques + + + align:start position:0% +important the ability to use techniques +such as the atom probe to actually + + align:start position:0% +such as the atom probe to actually + + + align:start position:0% +such as the atom probe to actually +measure the complex compositions of + + align:start position:0% +measure the complex compositions of + + + align:start position:0% +measure the complex compositions of +nanoscale strengthening precipitates in + + align:start position:0% +nanoscale strengthening precipitates in + + + align:start position:0% +nanoscale strengthening precipitates in +our ultra high strength materials so + + align:start position:0% +our ultra high strength materials so + + + align:start position:0% +our ultra high strength materials so +from the start uh uh calibration and + + align:start position:0% +from the start uh uh calibration and + + + align:start position:0% +from the start uh uh calibration and +validation to understand the associated + + align:start position:0% +validation to understand the associated + + + align:start position:0% +validation to understand the associated +uncertainty of our predictions was was + + align:start position:0% +uncertainty of our predictions was was + + + align:start position:0% +uncertainty of our predictions was was +really important uh and that's what the + + align:start position:0% +really important uh and that's what the + + + align:start position:0% +really important uh and that's what the +instrumentation was + + align:start position:0% +instrumentation was + + + align:start position:0% +instrumentation was +enabling so our first example uh + + align:start position:0% +enabling so our first example uh + + + align:start position:0% +enabling so our first example uh +starting out in the 1980s to design + + align:start position:0% +starting out in the 1980s to design + + + align:start position:0% +starting out in the 1980s to design +ultra high strength Steels uh we first + + align:start position:0% +ultra high strength Steels uh we first + + + align:start position:0% +ultra high strength Steels uh we first +took apart the highest performance steel + + align:start position:0% +took apart the highest performance steel + + + align:start position:0% +took apart the highest performance steel +of the time which was the af-1 1410 + + align:start position:0% +of the time which was the af-1 1410 + + + align:start position:0% +of the time which was the af-1 1410 +steel uh which is tempered at 510c to + + align:start position:0% +steel uh which is tempered at 510c to + + + align:start position:0% +steel uh which is tempered at 510c to +precipitate uh alloy m2c carbide so + + align:start position:0% +precipitate uh alloy m2c carbide so + + + align:start position:0% +precipitate uh alloy m2c carbide so +these are hcp carbides where the m is a + + align:start position:0% +these are hcp carbides where the m is a + + + align:start position:0% +these are hcp carbides where the m is a +combination of chromium album and vadium + + align:start position:0% +combination of chromium album and vadium + + + align:start position:0% +combination of chromium album and vadium +and sometimes + + align:start position:0% +and sometimes + + + align:start position:0% +and sometimes +tungsten uh so we brought together a + + align:start position:0% +tungsten uh so we brought together a + + + align:start position:0% +tungsten uh so we brought together a +wide array of uh techniques to map the + + align:start position:0% +wide array of uh techniques to map the + + + align:start position:0% +wide array of uh techniques to map the +time evolution of the precipitate uh + + align:start position:0% +time evolution of the precipitate uh + + + align:start position:0% +time evolution of the precipitate uh +particle size uh the aspect ratio of the + + align:start position:0% +particle size uh the aspect ratio of the + + + align:start position:0% +particle size uh the aspect ratio of the +carbides their number density total + + align:start position:0% +carbides their number density total + + + align:start position:0% +carbides their number density total +volume fraction uh and their uh uh the + + align:start position:0% +volume fraction uh and their uh uh the + + + align:start position:0% +volume fraction uh and their uh uh the +evolution of the carbide lce parameters + + align:start position:0% +evolution of the carbide lce parameters + + + align:start position:0% +evolution of the carbide lce parameters +and Associated composition trajectory + + align:start position:0% +and Associated composition trajectory + + + align:start position:0% +and Associated composition trajectory +and then this summarizes the evolution + + align:start position:0% +and then this summarizes the evolution + + + align:start position:0% +and then this summarizes the evolution +of the precipitation + + align:start position:0% +of the precipitation + + + align:start position:0% +of the precipitation +strengthening uh the evolution of the + + align:start position:0% +strengthening uh the evolution of the + + + align:start position:0% +strengthening uh the evolution of the +size uh was consistent with the theory + + align:start position:0% +size uh was consistent with the theory + + + align:start position:0% +size uh was consistent with the theory +of precipitation at high superp + + align:start position:0% +of precipitation at high superp + + + align:start position:0% +of precipitation at high superp +saturations and in that regime uh we can + + align:start position:0% +saturations and in that regime uh we can + + + align:start position:0% +saturations and in that regime uh we can +treat the initial critical nucleus size + + align:start position:0% +treat the initial critical nucleus size + + + align:start position:0% +treat the initial critical nucleus size +as the fundamental scaling factor for + + align:start position:0% +as the fundamental scaling factor for + + + align:start position:0% +as the fundamental scaling factor for +particle size that's so important to + + align:start position:0% +particle size that's so important to + + + align:start position:0% +particle size that's so important to +strengthening uh and that of course + + align:start position:0% +strengthening uh and that of course + + + align:start position:0% +strengthening uh and that of course +scales inversely with precipitation + + align:start position:0% +scales inversely with precipitation + + + align:start position:0% +scales inversely with precipitation +driving force so this is a way we could + + align:start position:0% +driving force so this is a way we could + + + align:start position:0% +driving force so this is a way we could +uh get a thermodynamic handle on the + + align:start position:0% +uh get a thermodynamic handle on the + + + align:start position:0% +uh get a thermodynamic handle on the +particle size that governs strengthening + + align:start position:0% +particle size that governs strengthening + + + align:start position:0% +particle size that governs strengthening +efficiency in these systems but it was + + align:start position:0% +efficiency in these systems but it was + + + align:start position:0% +efficiency in these systems but it was +important to recognize that the + + align:start position:0% +important to recognize that the + + + align:start position:0% +important to recognize that the +trajectory of the lattice parameters uh + + align:start position:0% +trajectory of the lattice parameters uh + + + align:start position:0% +trajectory of the lattice parameters uh +driven by the composition trajectory of + + align:start position:0% +driven by the composition trajectory of + + + align:start position:0% +driven by the composition trajectory of +the carbides is consistent with the + + align:start position:0% +the carbides is consistent with the + + + align:start position:0% +the carbides is consistent with the +initial nucleation being in a fully + + align:start position:0% +initial nucleation being in a fully + + + align:start position:0% +initial nucleation being in a fully +coherent state so it was necessary to + + align:start position:0% +coherent state so it was necessary to + + + align:start position:0% +coherent state so it was necessary to +add to the calad chemical Thermon namics + + align:start position:0% +add to the calad chemical Thermon namics + + + align:start position:0% +add to the calad chemical Thermon namics +and elastic energy term uh that's + + align:start position:0% +and elastic energy term uh that's + + + align:start position:0% +and elastic energy term uh that's +composition dependent through the + + align:start position:0% +composition dependent through the + + + align:start position:0% +composition dependent through the +composition dependence of the lattice + + align:start position:0% +composition dependence of the lattice + + + align:start position:0% +composition dependence of the lattice +parameter setting the misfit strains so + + align:start position:0% +parameter setting the misfit strains so + + + align:start position:0% +parameter setting the misfit strains so +all that was put together uh to get uh + + align:start position:0% +all that was put together uh to get uh + + + align:start position:0% +all that was put together uh to get uh +precise driving forces for the + + align:start position:0% +precise driving forces for the + + + align:start position:0% +precise driving forces for the +precipitation of these carbides so we + + align:start position:0% +precipitation of these carbides so we + + + align:start position:0% +precipitation of these carbides so we +could efficiently control the particle + + align:start position:0% +could efficiently control the particle + + + align:start position:0% +could efficiently control the particle +size and uh what that leads to then uh + + align:start position:0% +size and uh what that leads to then uh + + + align:start position:0% +size and uh what that leads to then uh +is this simplified parametric approach + + align:start position:0% +is this simplified parametric approach + + + align:start position:0% +is this simplified parametric approach +to strengthening where from the aoan uh + + align:start position:0% +to strengthening where from the aoan uh + + + align:start position:0% +to strengthening where from the aoan uh +strengthening Theory uh the + + align:start position:0% +strengthening Theory uh the + + + align:start position:0% +strengthening Theory uh the +precipitation strengthening scales + + align:start position:0% +precipitation strengthening scales + + + align:start position:0% +precipitation strengthening scales +inversely with the spacing of the + + align:start position:0% +inversely with the spacing of the + + + align:start position:0% +inversely with the spacing of the +obstacles uh and that spacing scales + + align:start position:0% +obstacles uh and that spacing scales + + + align:start position:0% +obstacles uh and that spacing scales +with particle size over phase fraction + + align:start position:0% +with particle size over phase fraction + + + align:start position:0% +with particle size over phase fraction +to the one half uh for the uh spacing uh + + align:start position:0% +to the one half uh for the uh spacing uh + + + align:start position:0% +to the one half uh for the uh spacing uh +in a slip plane uh and that means then + + align:start position:0% +in a slip plane uh and that means then + + + align:start position:0% +in a slip plane uh and that means then +uh the precipitation strengthening goes + + align:start position:0% +uh the precipitation strengthening goes + + + align:start position:0% +uh the precipitation strengthening goes +is f to the 1/2 over particle size and + + align:start position:0% +is f to the 1/2 over particle size and + + + align:start position:0% +is f to the 1/2 over particle size and +if we accept this scaling to the initial + + align:start position:0% +if we accept this scaling to the initial + + + align:start position:0% +if we accept this scaling to the initial +critical nucleus size that scales + + align:start position:0% +critical nucleus size that scales + + + align:start position:0% +critical nucleus size that scales +inversely to the driving force uh then + + align:start position:0% +inversely to the driving force uh then + + + align:start position:0% +inversely to the driving force uh then +we can write that the precipitation + + align:start position:0% +we can write that the precipitation + + + align:start position:0% +we can write that the precipitation +strengthening will will scale directly + + align:start position:0% +strengthening will will scale directly + + + align:start position:0% +strengthening will will scale directly +with that theramic driving force times + + align:start position:0% +with that theramic driving force times + + + align:start position:0% +with that theramic driving force times +phase fraction to the 1/2 uh so this + + align:start position:0% +phase fraction to the 1/2 uh so this + + + align:start position:0% +phase fraction to the 1/2 uh so this +predicted that uh we ought to be able to + + align:start position:0% +predicted that uh we ought to be able to + + + align:start position:0% +predicted that uh we ought to be able to +design Steels uh with higher driving + + align:start position:0% +design Steels uh with higher driving + + + align:start position:0% +design Steels uh with higher driving +forces to get more efficient uh + + align:start position:0% +forces to get more efficient uh + + + align:start position:0% +forces to get more efficient uh +strengthening and That Was Then tested + + align:start position:0% +strengthening and That Was Then tested + + + align:start position:0% +strengthening and That Was Then tested +by making a series of Steels that had a + + align:start position:0% +by making a series of Steels that had a + + + align:start position:0% +by making a series of Steels that had a +fixed carbon content setting uh the + + align:start position:0% +fixed carbon content setting uh the + + + align:start position:0% +fixed carbon content setting uh the +ultimate phase fraction of the + + align:start position:0% +ultimate phase fraction of the + + + align:start position:0% +ultimate phase fraction of the +precipitates uh and then we used our + + align:start position:0% +precipitates uh and then we used our + + + align:start position:0% +precipitates uh and then we used our +herent Thermon namics to predict the + + align:start position:0% +herent Thermon namics to predict the + + + align:start position:0% +herent Thermon namics to predict the +driving force uh but as well uh uh by + + align:start position:0% +driving force uh but as well uh uh by + + + align:start position:0% +driving force uh but as well uh uh by +the time we get to the temperatures + + align:start position:0% +the time we get to the temperatures + + + align:start position:0% +the time we get to the temperatures +where we can have sub substitutional + + align:start position:0% +where we can have sub substitutional + + + align:start position:0% +where we can have sub substitutional +diffusion uh the uh carbon diffusion + + align:start position:0% +diffusion uh the uh carbon diffusion + + + align:start position:0% +diffusion uh the uh carbon diffusion +controlled formation of iron carbides + + align:start position:0% +controlled formation of iron carbides + + + align:start position:0% +controlled formation of iron carbides +like fe3c will already have occurred and + + align:start position:0% +like fe3c will already have occurred and + + + align:start position:0% +like fe3c will already have occurred and +that lowers the chemical potential of + + align:start position:0% +that lowers the chemical potential of + + + align:start position:0% +that lowers the chemical potential of +the carbon so it was necessary to get + + align:start position:0% +the carbon so it was necessary to get + + + align:start position:0% +the carbon so it was necessary to get +these driving forces right uh we had to + + align:start position:0% +these driving forces right uh we had to + + + align:start position:0% +these driving forces right uh we had to +First consider a constrained equilibrium + + align:start position:0% +First consider a constrained equilibrium + + + align:start position:0% +First consider a constrained equilibrium +with + + align:start position:0% +with + + + align:start position:0% +with +fe3c uh to set the Carbon potential + + align:start position:0% +fe3c uh to set the Carbon potential + + + align:start position:0% +fe3c uh to set the Carbon potential +uh and then we were able to validate + + align:start position:0% +uh and then we were able to validate + + + align:start position:0% +uh and then we were able to validate +that with the within the scatter of + + align:start position:0% +that with the within the scatter of + + + align:start position:0% +that with the within the scatter of +these measurements uh the at at a fixed + + align:start position:0% +these measurements uh the at at a fixed + + + align:start position:0% +these measurements uh the at at a fixed +carbon level we could vary uh the the + + align:start position:0% +carbon level we could vary uh the the + + + align:start position:0% +carbon level we could vary uh the the +hardness the peak hardness of this + + align:start position:0% +hardness the peak hardness of this + + + align:start position:0% +hardness the peak hardness of this +strengthen steel over about 20 uh points + + align:start position:0% +strengthen steel over about 20 uh points + + + align:start position:0% +strengthen steel over about 20 uh points +on a rockable C scale so very dramatic + + align:start position:0% +on a rockable C scale so very dramatic + + + align:start position:0% +on a rockable C scale so very dramatic +uh direct uh proportionality predicted + + align:start position:0% +uh direct uh proportionality predicted + + + align:start position:0% +uh direct uh proportionality predicted +by the model and so that calibration + + align:start position:0% +by the model and so that calibration + + + align:start position:0% +by the model and so that calibration +became the the principal tool that we + + align:start position:0% +became the the principal tool that we + + + align:start position:0% +became the the principal tool that we +used to design Steels with much more + + align:start position:0% +used to design Steels with much more + + + align:start position:0% +used to design Steels with much more +efficient strength + + align:start position:0% +efficient strength + + + align:start position:0% +efficient strength +uh demonstrating Alloys that for a given + + align:start position:0% +uh demonstrating Alloys that for a given + + + align:start position:0% +uh demonstrating Alloys that for a given +carbon content could have 50% more + + align:start position:0% +carbon content could have 50% more + + + align:start position:0% +carbon content could have 50% more +strength than than the previous + + align:start position:0% +strength than than the previous + + + align:start position:0% +strength than than the previous +technology so it's an area that's been + + align:start position:0% +technology so it's an area that's been + + + align:start position:0% +technology so it's an area that's been +uh highly developed + + align:start position:0% +uh highly developed + + + align:start position:0% +uh highly developed +empirically uh but in fact uh there was + + align:start position:0% +empirically uh but in fact uh there was + + + align:start position:0% +empirically uh but in fact uh there was +a lot more to be achieved by being more + + align:start position:0% +a lot more to be achieved by being more + + + align:start position:0% +a lot more to be achieved by being more +predictive and taking systems to a high + + align:start position:0% +predictive and taking systems to a high + + + align:start position:0% +predictive and taking systems to a high +level uh of optimization using these + + align:start position:0% + + + + align:start position:0% + +tools now what I wanted to uh just touch + + align:start position:0% +tools now what I wanted to uh just touch + + + align:start position:0% +tools now what I wanted to uh just touch +on is uh there's also an important role + + align:start position:0% +on is uh there's also an important role + + + align:start position:0% +on is uh there's also an important role +of the surface thermodynamics and uh + + align:start position:0% +of the surface thermodynamics and uh + + + align:start position:0% +of the surface thermodynamics and uh +this is a case where we made very good + + align:start position:0% +this is a case where we made very good + + + align:start position:0% +this is a case where we made very good +use of the DFT predictions uh but what + + align:start position:0% +use of the DFT predictions uh but what + + + align:start position:0% +use of the DFT predictions uh but what +this chart is about is a correlation of + + align:start position:0% +this chart is about is a correlation of + + + align:start position:0% +this chart is about is a correlation of +the embrittlement potency of interfacial + + align:start position:0% +the embrittlement potency of interfacial + + + align:start position:0% +the embrittlement potency of interfacial +segregants uh against the uh segregation + + align:start position:0% +segregants uh against the uh segregation + + + align:start position:0% +segregants uh against the uh segregation +energy difference between free surfaces + + align:start position:0% +energy difference between free surfaces + + + align:start position:0% +energy difference between free surfaces +and grain boundaries uh and in this case + + align:start position:0% +and grain boundaries uh and in this case + + + align:start position:0% +and grain boundaries uh and in this case +uh there is experimental data to to + + align:start position:0% +uh there is experimental data to to + + + align:start position:0% +uh there is experimental data to to +validate this but this is actually the + + align:start position:0% +validate this but this is actually the + + + align:start position:0% +validate this but this is actually the +case of uh predicting it with our DFT + + align:start position:0% +case of uh predicting it with our DFT + + + align:start position:0% +case of uh predicting it with our DFT +mechanics with pretty good accuracy uh + + align:start position:0% +mechanics with pretty good accuracy uh + + + align:start position:0% +mechanics with pretty good accuracy uh +so these are the well-known interstitial + + align:start position:0% +so these are the well-known interstitial + + + align:start position:0% +so these are the well-known interstitial +components that have been well studied + + align:start position:0% +components that have been well studied + + + align:start position:0% +components that have been well studied +substitutional elements were less well + + align:start position:0% +substitutional elements were less well + + + align:start position:0% +substitutional elements were less well +studied uh so after demonstrating the + + align:start position:0% +studied uh so after demonstrating the + + + align:start position:0% +studied uh so after demonstrating the +ability to compute these numbers we + + align:start position:0% +ability to compute these numbers we + + + align:start position:0% +ability to compute these numbers we +actually built out this database of the + + align:start position:0% +actually built out this database of the + + + align:start position:0% +actually built out this database of the +embrittlement potency from surface + + align:start position:0% +embrittlement potency from surface + + + align:start position:0% +embrittlement potency from surface +thermodynamics uh which was calibrated + + align:start position:0% +thermodynamics uh which was calibrated + + + align:start position:0% +thermodynamics uh which was calibrated +and validated by some large scale uh DFT + + align:start position:0% +and validated by some large scale uh DFT + + + align:start position:0% +and validated by some large scale uh DFT +calculations uh giving us these + + align:start position:0% +calculations uh giving us these + + + align:start position:0% +calculations uh giving us these +predictions from which were able to + + align:start position:0% +predictions from which were able to + + + align:start position:0% +predictions from which were able to +identify these strong cohesion + + align:start position:0% +identify these strong cohesion + + + align:start position:0% +identify these strong cohesion +enhancers uh that could sufficiently + + align:start position:0% +enhancers uh that could sufficiently + + + align:start position:0% +enhancers uh that could sufficiently +enhance grain boundary cohesion to + + align:start position:0% +enhance grain boundary cohesion to + + + align:start position:0% +enhance grain boundary cohesion to +offset the embrittling effect of + + align:start position:0% +offset the embrittling effect of + + + align:start position:0% +offset the embrittling effect of +hydrogen and this allowed us to design + + align:start position:0% +hydrogen and this allowed us to design + + + align:start position:0% +hydrogen and this allowed us to design +these very high performance Steels to to + + align:start position:0% +these very high performance Steels to to + + + align:start position:0% +these very high performance Steels to to +no longer uh be prone to the + + align:start position:0% +no longer uh be prone to the + + + align:start position:0% +no longer uh be prone to the +intergranular form of stress corrosion + + align:start position:0% +intergranular form of stress corrosion + + + align:start position:0% +intergranular form of stress corrosion +cracking so it was a big advance in the + + align:start position:0% +cracking so it was a big advance in the + + + align:start position:0% +cracking so it was a big advance in the +resistance to hydrogen embrittlement in + + align:start position:0% +resistance to hydrogen embrittlement in + + + align:start position:0% +resistance to hydrogen embrittlement in +these class of Steels so it's one + + align:start position:0% +these class of Steels so it's one + + + align:start position:0% +these class of Steels so it's one +example yeah one second can can you um + + align:start position:0% +example yeah one second can can you um + + + align:start position:0% +example yeah one second can can you um +fill in what is DFT + + align:start position:0% +fill in what is DFT + + + align:start position:0% +fill in what is DFT +cou times at this point we talk about + + align:start position:0% +cou times at this point we talk about + + + align:start position:0% +cou times at this point we talk about +data a lot so where does that data come + + align:start position:0% +data a lot so where does that data come + + + align:start position:0% +data a lot so where does that data come +from yeah so that density functional + + align:start position:0% +from yeah so that density functional + + + align:start position:0% +from yeah so that density functional +Theory so so this is uh something that + + align:start position:0% +Theory so so this is uh something that + + + align:start position:0% +Theory so so this is uh something that +we basically have ways to solve the + + align:start position:0% +we basically have ways to solve the + + + align:start position:0% +we basically have ways to solve the +Schrodinger equation uh but there is a + + align:start position:0% +Schrodinger equation uh but there is a + + + align:start position:0% +Schrodinger equation uh but there is a +menu of approximations that you do take + + align:start position:0% +menu of approximations that you do take + + + align:start position:0% +menu of approximations that you do take +along the way uh but it really is + + align:start position:0% +along the way uh but it really is + + + align:start position:0% +along the way uh but it really is +essentially first principal prediction + + align:start position:0% +essentially first principal prediction + + + align:start position:0% +essentially first principal prediction +of energy at zero Kelvin right thank so + + align:start position:0% +of energy at zero Kelvin right thank so + + + align:start position:0% +of energy at zero Kelvin right thank so +we we we use a lot of empirical data in + + align:start position:0% +we we we use a lot of empirical data in + + + align:start position:0% +we we we use a lot of empirical data in +o2o + + align:start position:0% +o2o + + + align:start position:0% +o2o +but you've also probably used um DFT + + align:start position:0% +but you've also probably used um DFT + + + align:start position:0% +but you've also probably used um DFT +derived data even without knowing it so + + align:start position:0% +derived data even without knowing it so + + + align:start position:0% +derived data even without knowing it so +when you have some materials Property + + align:start position:0% +when you have some materials Property + + + align:start position:0% +when you have some materials Property +Data it comes from somewhere and + + align:start position:0% +Data it comes from somewhere and + + + align:start position:0% +Data it comes from somewhere and +sometimes it comes from Theory and + + align:start position:0% +sometimes it comes from Theory and + + + align:start position:0% +sometimes it comes from Theory and +sometimes it comes from measurement and + + align:start position:0% +sometimes it comes from measurement and + + + align:start position:0% +sometimes it comes from measurement and +um oftentimes if it comes from Theory + + align:start position:0% +um oftentimes if it comes from Theory + + + align:start position:0% +um oftentimes if it comes from Theory +comes from DFD + + align:start position:0% +comes from DFD + + + align:start position:0% +comes from DFD +calculations yeah it it is and and uh in + + align:start position:0% +calculations yeah it it is and and uh in + + + align:start position:0% +calculations yeah it it is and and uh in +this there are different approximations + + align:start position:0% +this there are different approximations + + + align:start position:0% +this there are different approximations +and this was an all electron method very + + align:start position:0% +and this was an all electron method very + + + align:start position:0% +and this was an all electron method very +rigorous but it was typically something + + align:start position:0% +rigorous but it was typically something + + + align:start position:0% +rigorous but it was typically something +like 400 hours of super computer time + + align:start position:0% +like 400 hours of super computer time + + + align:start position:0% +like 400 hours of super computer time +for each data point back in the 1980s + + align:start position:0% +for each data point back in the 1980s + + + align:start position:0% +for each data point back in the 1980s +when + + align:start position:0% +when + + + align:start position:0% +when +we asked a question which do you prefer + + align:start position:0% +we asked a question which do you prefer + + + align:start position:0% +we asked a question which do you prefer +I think you mean which I prefer + + align:start position:0% +I think you mean which I prefer + + + align:start position:0% +I think you mean which I prefer +experiment of theory um is that what you + + align:start position:0% +experiment of theory um is that what you + + + align:start position:0% +experiment of theory um is that what you +meant here speak of if you unmute + + align:start position:0% +meant here speak of if you unmute + + + align:start position:0% +meant here speak of if you unmute +yourself it's it's more fun yeah uh I + + align:start position:0% +yourself it's it's more fun yeah uh I + + + align:start position:0% +yourself it's it's more fun yeah uh I +mean like for the applications like of + + align:start position:0% +mean like for the applications like of + + + align:start position:0% +mean like for the applications like of +prediction which is better to + + align:start position:0% +prediction which is better to + + + align:start position:0% +prediction which is better to +extrapolate + + align:start position:0% +extrapolate + + + align:start position:0% +extrapolate +uh so Greg if you had your choice be I + + align:start position:0% +uh so Greg if you had your choice be I + + + align:start position:0% +uh so Greg if you had your choice be I +mean uh I'll just say first of all it's + + align:start position:0% +mean uh I'll just say first of all it's + + + align:start position:0% +mean uh I'll just say first of all it's +often not it's often an apples to + + align:start position:0% +often not it's often an apples to + + + align:start position:0% +often not it's often an apples to +oranges comparison because we use DFT + + align:start position:0% +oranges comparison because we use DFT + + + align:start position:0% +oranges comparison because we use DFT +most often to get data for processes or + + align:start position:0% +most often to get data for processes or + + + align:start position:0% +most often to get data for processes or +situations that we just can't measure + + align:start position:0% +situations that we just can't measure + + + align:start position:0% +situations that we just can't measure +yeah which I think gives you your answer + + align:start position:0% +yeah which I think gives you your answer + + + align:start position:0% +yeah which I think gives you your answer +if you have Apples to Apples if you have + + align:start position:0% +if you have Apples to Apples if you have + + + align:start position:0% +if you have Apples to Apples if you have +a measurement and a calculation of the + + align:start position:0% +a measurement and a calculation of the + + + align:start position:0% +a measurement and a calculation of the +same thing in the same circumstance I + + align:start position:0% +same thing in the same circumstance I + + + align:start position:0% +same thing in the same circumstance I +think Greg and I would would agree we we + + align:start position:0% +think Greg and I would would agree we we + + + align:start position:0% +think Greg and I would would agree we we +if the measurement's a good one um we go + + align:start position:0% +if the measurement's a good one um we go + + + align:start position:0% +if the measurement's a good one um we go +with that yeah if you look at the + + align:start position:0% +with that yeah if you look at the + + + align:start position:0% +with that yeah if you look at the +magnitude of this uh you know we're + + align:start position:0% +magnitude of this uh you know we're + + + align:start position:0% +magnitude of this uh you know we're +we're using this method to find uh the + + align:start position:0% +we're using this method to find uh the + + + align:start position:0% +we're using this method to find uh the +one that have this cohesion enhancing + + align:start position:0% +one that have this cohesion enhancing + + + align:start position:0% +one that have this cohesion enhancing +potency of greater than one + + align:start position:0% +potency of greater than one + + + align:start position:0% +potency of greater than one +EV and the intrinsic uncertainty of even + + align:start position:0% +EV and the intrinsic uncertainty of even + + + align:start position:0% +EV and the intrinsic uncertainty of even +these calculations is about 0.1 EV and + + align:start position:0% +these calculations is about 0.1 EV and + + + align:start position:0% +these calculations is about 0.1 EV and +this other model got it within 0. 2 EV + + align:start position:0% +this other model got it within 0. 2 EV + + + align:start position:0% +this other model got it within 0. 2 EV +so uh it is important to understand the + + align:start position:0% +so uh it is important to understand the + + + align:start position:0% +so uh it is important to understand the +uncertainty of those predictions so if + + align:start position:0% +uncertainty of those predictions so if + + + align:start position:0% +uncertainty of those predictions so if +it's plus or minus 0.1 AV that's fine + + align:start position:0% +it's plus or minus 0.1 AV that's fine + + + align:start position:0% +it's plus or minus 0.1 AV that's fine +for helping you find the 1 EV candidates + + align:start position:0% +for helping you find the 1 EV candidates + + + align:start position:0% +for helping you find the 1 EV candidates +but most often in Metallurgy the number + + align:start position:0% +but most often in Metallurgy the number + + + align:start position:0% +but most often in Metallurgy the number +we want to know is only of the magnitude + + align:start position:0% +we want to know is only of the magnitude + + + align:start position:0% +we want to know is only of the magnitude +0.1 and 0.1 Plus or minus .1 is not very + + align:start position:0% +0.1 and 0.1 Plus or minus .1 is not very + + + align:start position:0% +0.1 and 0.1 Plus or minus .1 is not very +useful uh so it's a good way to to find + + align:start position:0% +useful uh so it's a good way to to find + + + align:start position:0% +useful uh so it's a good way to to find +out where to go for the big numbers but + + align:start position:0% +out where to go for the big numbers but + + + align:start position:0% +out where to go for the big numbers but +most of the time uh we really need the + + align:start position:0% +most of the time uh we really need the + + + align:start position:0% +most of the time uh we really need the +experimental data that gives us higher + + align:start position:0% +experimental data that gives us higher + + + align:start position:0% +experimental data that gives us higher +accuracy than we can get currently from + + align:start position:0% +accuracy than we can get currently from + + + align:start position:0% +accuracy than we can get currently from +the DFT + + align:start position:0% + + + + align:start position:0% + +methods y so that's why I was saying + + align:start position:0% +methods y so that's why I was saying + + + align:start position:0% +methods y so that's why I was saying +that upfront uncertainty quantification + + align:start position:0% +that upfront uncertainty quantification + + + align:start position:0% +that upfront uncertainty quantification +was a very important part of the whole + + align:start position:0% +was a very important part of the whole + + + align:start position:0% +was a very important part of the whole +strategy of putting these tools + + align:start position:0% + + + + align:start position:0% + +together okay but this is a good example + + align:start position:0% +together okay but this is a good example + + + align:start position:0% +together okay but this is a good example +of maximum use of DFT we had a small set + + align:start position:0% +of maximum use of DFT we had a small set + + + align:start position:0% +of maximum use of DFT we had a small set +of experimental surface thermodynamics + + align:start position:0% +of experimental surface thermodynamics + + + align:start position:0% +of experimental surface thermodynamics +to test against uh and then we could + + align:start position:0% +to test against uh and then we could + + + align:start position:0% +to test against uh and then we could +calibrate against the ability of DFT to + + align:start position:0% +calibrate against the ability of DFT to + + + align:start position:0% +calibrate against the ability of DFT to +predict it uh and then make this + + align:start position:0% +predict it uh and then make this + + + align:start position:0% +predict it uh and then make this +projection across the periodic table so + + align:start position:0% +projection across the periodic table so + + + align:start position:0% +projection across the periodic table so +it's a a surface theramic genome almost + + align:start position:0% +it's a a surface theramic genome almost + + + align:start position:0% +it's a a surface theramic genome almost +entirely from DFT + + align:start position:0% + + + + align:start position:0% + +calculations and the way we put it all + + align:start position:0% +calculations and the way we put it all + + + align:start position:0% +calculations and the way we put it all +together is graphical parametric design + + align:start position:0% +together is graphical parametric design + + + align:start position:0% +together is graphical parametric design +so we map the behaviors of Interest back + + align:start position:0% +so we map the behaviors of Interest back + + + align:start position:0% +so we map the behaviors of Interest back +to these parameters like driving force + + align:start position:0% +to these parameters like driving force + + + align:start position:0% +to these parameters like driving force +and phas fraction for strengthening and + + align:start position:0% +and phas fraction for strengthening and + + + align:start position:0% +and phas fraction for strengthening and +so for the actual stainless landing gear + + align:start position:0% +so for the actual stainless landing gear + + + align:start position:0% +so for the actual stainless landing gear +steel uh here's a crossplot versus malum + + align:start position:0% +steel uh here's a crossplot versus malum + + + align:start position:0% +steel uh here's a crossplot versus malum +content affecting the driving force and + + align:start position:0% +content affecting the driving force and + + + align:start position:0% +content affecting the driving force and +the carbon affecting the phase fraction + + align:start position:0% +the carbon affecting the phase fraction + + + align:start position:0% +the carbon affecting the phase fraction +and there are a couple invisible yellow + + align:start position:0% +and there are a couple invisible yellow + + + align:start position:0% +and there are a couple invisible yellow +cont Contour showing how the driving + + align:start position:0% +cont Contour showing how the driving + + + align:start position:0% +cont Contour showing how the driving +force increases with meibum and of + + align:start position:0% +force increases with meibum and of + + + align:start position:0% +force increases with meibum and of +course the carbon sets the phase + + align:start position:0% +course the carbon sets the phase + + + align:start position:0% +course the carbon sets the phase +fraction so it's this region in here uh + + align:start position:0% +fraction so it's this region in here uh + + + align:start position:0% +fraction so it's this region in here uh +that gave us the strength level uh that + + align:start position:0% +that gave us the strength level uh that + + + align:start position:0% +that gave us the strength level uh that +is our goal for the design and super + + align:start position:0% +is our goal for the design and super + + + align:start position:0% +is our goal for the design and super +proposed on that are processability + + align:start position:0% +proposed on that are processability + + + align:start position:0% +proposed on that are processability +constraints such as the Martin site + + align:start position:0% +constraints such as the Martin site + + + align:start position:0% +constraints such as the Martin site +start temperature to have a fully Martin + + align:start position:0% +start temperature to have a fully Martin + + + align:start position:0% +start temperature to have a fully Martin +sutic steel and the solution temperature + + align:start position:0% +sutic steel and the solution temperature + + + align:start position:0% +sutic steel and the solution temperature +to put the reactive components in + + align:start position:0% +to put the reactive components in + + + align:start position:0% +to put the reactive components in +solution so we can precipitate them uh + + align:start position:0% +solution so we can precipitate them uh + + + align:start position:0% +solution so we can precipitate them uh +at at high temperatures uh and the + + align:start position:0% +at at high temperatures uh and the + + + align:start position:0% +at at high temperatures uh and the +relative slopes that we can see from + + align:start position:0% +relative slopes that we can see from + + + align:start position:0% +relative slopes that we can see from +these types of plots also allow us to + + align:start position:0% +these types of plots also allow us to + + + align:start position:0% +these types of plots also allow us to +assess relative sensitivities so we can + + align:start position:0% +assess relative sensitivities so we can + + + align:start position:0% +assess relative sensitivities so we can +develop robust uh design strategies that + + align:start position:0% +develop robust uh design strategies that + + + align:start position:0% +develop robust uh design strategies that +that are that don't require too tight of + + align:start position:0% +that are that don't require too tight of + + + align:start position:0% +that are that don't require too tight of +Tolerance uh so quite typically we we + + align:start position:0% +Tolerance uh so quite typically we we + + + align:start position:0% +Tolerance uh so quite typically we we +start from the last stage of processing + + align:start position:0% +start from the last stage of processing + + + align:start position:0% +start from the last stage of processing +the the nanoscale precipitation that + + align:start position:0% +the the nanoscale precipitation that + + + align:start position:0% +the the nanoscale precipitation that +meets the strength goals and then back + + align:start position:0% +meets the strength goals and then back + + + align:start position:0% +meets the strength goals and then back +up to earlier stages of processing we + + align:start position:0% +up to earlier stages of processing we + + + align:start position:0% +up to earlier stages of processing we +were also using uh these FCC MC type + + align:start position:0% +were also using uh these FCC MC type + + + align:start position:0% +were also using uh these FCC MC type +carbides in this case we've got a a + + align:start position:0% +carbides in this case we've got a a + + + align:start position:0% +carbides in this case we've got a a +composition variable in the processed + + align:start position:0% +composition variable in the processed + + + align:start position:0% +composition variable in the processed +temperature so we're constraining these + + align:start position:0% +temperature so we're constraining these + + + align:start position:0% +temperature so we're constraining these +grain refining particles to be soluble + + align:start position:0% +grain refining particles to be soluble + + + align:start position:0% +grain refining particles to be soluble +at homogeneization temperatures able to + + align:start position:0% +at homogeneization temperatures able to + + + align:start position:0% +at homogeneization temperatures able to +precipitate out at forging temperatures + + align:start position:0% +precipitate out at forging temperatures + + + align:start position:0% +precipitate out at forging temperatures +and then maintain a certain phase + + align:start position:0% +and then maintain a certain phase + + + align:start position:0% +and then maintain a certain phase +fraction in size at the final + + align:start position:0% +fraction in size at the final + + + align:start position:0% +fraction in size at the final +austenitizing temperature of the steel + + align:start position:0% +austenitizing temperature of the steel + + + align:start position:0% +austenitizing temperature of the steel +uh that sets the grain size of the steel + + align:start position:0% +uh that sets the grain size of the steel + + + align:start position:0% +uh that sets the grain size of the steel +so similarly we can back up to even + + align:start position:0% +so similarly we can back up to even + + + align:start position:0% +so similarly we can back up to even +earlier stages of processing specify the + + align:start position:0% +earlier stages of processing specify the + + + align:start position:0% +earlier stages of processing specify the +deoxidation processes that set the + + align:start position:0% +deoxidation processes that set the + + + align:start position:0% +deoxidation processes that set the +primary inclusions at the multi Micron + + align:start position:0% +primary inclusions at the multi Micron + + + align:start position:0% +primary inclusions at the multi Micron +level that are important to toughness + + align:start position:0% +level that are important to toughness + + + align:start position:0% +level that are important to toughness +and fatigue resistance uh but that + + align:start position:0% +and fatigue resistance uh but that + + + align:start position:0% +and fatigue resistance uh but that +graphical strategy uh is uh very + + align:start position:0% +graphical strategy uh is uh very + + + align:start position:0% +graphical strategy uh is uh very +efficient uh and it is the practice that + + align:start position:0% +efficient uh and it is the practice that + + + align:start position:0% +efficient uh and it is the practice that +we use at questec and the practice that + + align:start position:0% +we use at questec and the practice that + + + align:start position:0% +we use at questec and the practice that +I teach in my design + + align:start position:0% + + + + align:start position:0% + +class so the first four products uh to + + align:start position:0% +class so the first four products uh to + + + align:start position:0% +class so the first four products uh to +come out of that are are these high + + align:start position:0% +come out of that are are these high + + + align:start position:0% +come out of that are are these high +performance secondary hardening Steels + + align:start position:0% +performance secondary hardening Steels + + + align:start position:0% +performance secondary hardening Steels +uh we have now two uh flight qualified + + align:start position:0% +uh we have now two uh flight qualified + + + align:start position:0% +uh we have now two uh flight qualified +Steels as as well as the stainless + + align:start position:0% +Steels as as well as the stainless + + + align:start position:0% +Steels as as well as the stainless +that's used by the air force uh we have + + align:start position:0% +that's used by the air force uh we have + + + align:start position:0% +that's used by the air force uh we have +a high toughness steel uh that's first + + align:start position:0% +a high toughness steel uh that's first + + + align:start position:0% +a high toughness steel uh that's first +gone into the hook shank application for + + align:start position:0% +gone into the hook shank application for + + + align:start position:0% +gone into the hook shank application for +the carrier-based uh planes uh so both + + align:start position:0% +the carrier-based uh planes uh so both + + + align:start position:0% +the carrier-based uh planes uh so both +of those Steels are flying uh we also + + align:start position:0% +of those Steels are flying uh we also + + + align:start position:0% +of those Steels are flying uh we also +have very high performance carbonizing + + align:start position:0% +have very high performance carbonizing + + + align:start position:0% +have very high performance carbonizing +steals for gear Gear steals for fatigue + + align:start position:0% +steals for gear Gear steals for fatigue + + + align:start position:0% +steals for gear Gear steals for fatigue +resistance and that's doing well uh on + + align:start position:0% +resistance and that's doing well uh on + + + align:start position:0% +resistance and that's doing well uh on +off-road and on track racing uh and in + + align:start position:0% +off-road and on track racing uh and in + + + align:start position:0% +off-road and on track racing uh and in +fact uh the Red Bull Formula 1 team + + align:start position:0% +fact uh the Red Bull Formula 1 team + + + align:start position:0% +fact uh the Red Bull Formula 1 team +that's very competitive this year is + + align:start position:0% +that's very competitive this year is + + + align:start position:0% +that's very competitive this year is +actually using our gear steals for uh + + align:start position:0% +actually using our gear steals for uh + + + align:start position:0% +actually using our gear steals for uh +for their + + align:start position:0% +for their + + + align:start position:0% +for their +reliability uh and those gear steals now + + align:start position:0% +reliability uh and those gear steals now + + + align:start position:0% +reliability uh and those gear steals now +are being qualified for helicopter + + align:start position:0% +are being qualified for helicopter + + + align:start position:0% +are being qualified for helicopter +applications uh but all of these benefit + + align:start position:0% +applications uh but all of these benefit + + + align:start position:0% +applications uh but all of these benefit +uh from that extra uh strengthening + + align:start position:0% +uh from that extra uh strengthening + + + align:start position:0% +uh from that extra uh strengthening +efficiency that we get by refining those + + align:start position:0% +efficiency that we get by refining those + + + align:start position:0% +efficiency that we get by refining those +m2c carbides down to a 3 nanometer size + + align:start position:0% +m2c carbides down to a 3 nanometer size + + + align:start position:0% +m2c carbides down to a 3 nanometer size +scale through that maximization of + + align:start position:0% +scale through that maximization of + + + align:start position:0% +scale through that maximization of +driving force as validated here by an + + align:start position:0% +driving force as validated here by an + + + align:start position:0% +driving force as validated here by an +early 3D atom probe reconstruction so + + align:start position:0% +early 3D atom probe reconstruction so + + + align:start position:0% +early 3D atom probe reconstruction so +all four of those Steels are using + + align:start position:0% +all four of those Steels are using + + + align:start position:0% +all four of those Steels are using +greater strengthening efficiency to + + align:start position:0% +greater strengthening efficiency to + + + align:start position:0% +greater strengthening efficiency to +resolve the conflict between with other + + align:start position:0% +resolve the conflict between with other + + + align:start position:0% +resolve the conflict between with other +properties GRE uh this is the maybe the + + align:start position:0% +properties GRE uh this is the maybe the + + + align:start position:0% +properties GRE uh this is the maybe the +second or more time you've mentioned + + align:start position:0% +second or more time you've mentioned + + + align:start position:0% +second or more time you've mentioned +Adam probe and there's data set right in + + align:start position:0% +Adam probe and there's data set right in + + + align:start position:0% +Adam probe and there's data set right in +the middle here so it seems like a good + + align:start position:0% +the middle here so it seems like a good + + + align:start position:0% +the middle here so it seems like a good +opportunity to talk about what that is + + align:start position:0% +opportunity to talk about what that is + + + align:start position:0% +opportunity to talk about what that is +yes the uh atom probe is a a version of + + align:start position:0% +yes the uh atom probe is a a version of + + + align:start position:0% +yes the uh atom probe is a a version of +the field ion microscope uh that that + + align:start position:0% +the field ion microscope uh that that + + + align:start position:0% +the field ion microscope uh that that +looks at the point of a very sharp pin + + align:start position:0% +looks at the point of a very sharp pin + + + align:start position:0% +looks at the point of a very sharp pin +to get very high electric + + align:start position:0% +to get very high electric + + + align:start position:0% +to get very high electric +Fields uh and uh it can actually cause + + align:start position:0% +Fields uh and uh it can actually cause + + + align:start position:0% +Fields uh and uh it can actually cause +evaporation from the high Fields uh and + + align:start position:0% +evaporation from the high Fields uh and + + + align:start position:0% +evaporation from the high Fields uh and +so we can evaporate atoms off of the tip + + align:start position:0% +so we can evaporate atoms off of the tip + + + align:start position:0% +so we can evaporate atoms off of the tip +and project them to a position sensitive + + align:start position:0% +and project them to a position sensitive + + + align:start position:0% +and project them to a position sensitive +detector and actually reconstruct the + + align:start position:0% +detector and actually reconstruct the + + + align:start position:0% +detector and actually reconstruct the +position all the atoms in the tip so it + + align:start position:0% +position all the atoms in the tip so it + + + align:start position:0% +position all the atoms in the tip so it +really is uh taking us down to nanoscale + + align:start position:0% +really is uh taking us down to nanoscale + + + align:start position:0% +really is uh taking us down to nanoscale +uh spatial + + align:start position:0% +uh spatial + + + align:start position:0% +uh spatial +resolution uh with detectability of all + + align:start position:0% +resolution uh with detectability of all + + + align:start position:0% +resolution uh with detectability of all +atoms in in the periodic table so a very + + align:start position:0% +atoms in in the periodic table so a very + + + align:start position:0% +atoms in in the periodic table so a very +powerful technique I may it pulls a part + + align:start position:0% +powerful technique I may it pulls a part + + + align:start position:0% +powerful technique I may it pulls a part +of material at of by atom and tells you + + align:start position:0% +of material at of by atom and tells you + + + align:start position:0% +of material at of by atom and tells you +where all the atoms were + + align:start position:0% +where all the atoms were + + + align:start position:0% +where all the atoms were +yep that's what it does + + align:start position:0% +yep that's what it does + + + align:start position:0% +yep that's what it does +yes and we have very good facility at + + align:start position:0% +yes and we have very good facility at + + + align:start position:0% +yes and we have very good facility at +Northwestern but there's also a very + + align:start position:0% +Northwestern but there's also a very + + + align:start position:0% +Northwestern but there's also a very +good one uh at at Harvard that we're + + align:start position:0% +good one uh at at Harvard that we're + + + align:start position:0% +good one uh at at Harvard that we're +we're using now + + align:start position:0% +we're using now + + + align:start position:0% +we're using now +oh can you use the material after that + + align:start position:0% +oh can you use the material after that + + + align:start position:0% +oh can you use the material after that +like does it change the + + align:start position:0% +like does it change the + + + align:start position:0% +like does it change the +surface uh yeah this is uh this is true + + align:start position:0% +surface uh yeah this is uh this is true + + + align:start position:0% +surface uh yeah this is uh this is true +tomography so we're fully we are really + + align:start position:0% +tomography so we're fully we are really + + + align:start position:0% +tomography so we're fully we are really +toing the material and taking it apart + + align:start position:0% +toing the material and taking it apart + + + align:start position:0% +toing the material and taking it apart +uh but one thing we can do uh is before + + align:start position:0% +uh but one thing we can do uh is before + + + align:start position:0% +uh but one thing we can do uh is before +we do the tomography we can look at the + + align:start position:0% +we do the tomography we can look at the + + + align:start position:0% +we do the tomography we can look at the +tip uh in the electron microscope so we + + align:start position:0% +tip uh in the electron microscope so we + + + align:start position:0% +tip uh in the electron microscope so we +can get defraction information + + align:start position:0% +can get defraction information + + + align:start position:0% +can get defraction information +crystalographic data fully characterize + + align:start position:0% +crystalographic data fully characterize + + + align:start position:0% +crystalographic data fully characterize +the tip inm before we then take it apart + + align:start position:0% +the tip inm before we then take it apart + + + align:start position:0% +the tip inm before we then take it apart +in the anap but it does it's like + + align:start position:0% +in the anap but it does it's like + + + align:start position:0% +in the anap but it does it's like +getting beamed up but you're never + + align:start position:0% +getting beamed up but you're never + + + align:start position:0% +getting beamed up but you're never +getting beam back down that's right + + align:start position:0% +getting beam back down that's right + + + align:start position:0% +getting beam back down that's right +tears the material of heart Adam by Adam + + align:start position:0% +tears the material of heart Adam by Adam + + + align:start position:0% +tears the material of heart Adam by Adam +and does not put it back together again + + align:start position:0% +and does not put it back together again + + + align:start position:0% +and does not put it back together again +right it well it puts it back together + + align:start position:0% +right it well it puts it back together + + + align:start position:0% +right it well it puts it back together +theoretically + + align:start position:0% +theoretically + + + align:start position:0% +theoretically +right yeah so we reassemble it as + + align:start position:0% +right yeah so we reassemble it as + + + align:start position:0% +right yeah so we reassemble it as +tomography + + align:start position:0% + + + + align:start position:0% + +yep all + + align:start position:0% + + + + align:start position:0% + +right yeah I would uh just touch on the + + align:start position:0% +right yeah I would uh just touch on the + + + align:start position:0% +right yeah I would uh just touch on the +the DARPA aim initiative again this this + + align:start position:0% +the DARPA aim initiative again this this + + + align:start position:0% +the DARPA aim initiative again this this +uh full compression of the cycle is this + + align:start position:0% +uh full compression of the cycle is this + + + align:start position:0% +uh full compression of the cycle is this +linking uh to macroscopic process models + + align:start position:0% +linking uh to macroscopic process models + + + align:start position:0% +linking uh to macroscopic process models +and so we were able to work with GE and + + align:start position:0% +and so we were able to work with GE and + + + align:start position:0% +and so we were able to work with GE and +pratton Whitney and and learn about the + + align:start position:0% +pratton Whitney and and learn about the + + + align:start position:0% +pratton Whitney and and learn about the +technology of multidisiplinary + + align:start position:0% +technology of multidisiplinary + + + align:start position:0% +technology of multidisiplinary +computational engineering so this + + align:start position:0% +computational engineering so this + + + align:start position:0% +computational engineering so this +integrator was linked to all to the + + align:start position:0% +integrator was linked to all to the + + + align:start position:0% +integrator was linked to all to the +tools of macroscopic aerot turbine + + align:start position:0% +tools of macroscopic aerot turbine + + + align:start position:0% +tools of macroscopic aerot turbine +engine design uh including heat transfer + + align:start position:0% +engine design uh including heat transfer + + + align:start position:0% +engine design uh including heat transfer +for heat treatment so we built this + + align:start position:0% +for heat treatment so we built this + + + align:start position:0% +for heat treatment so we built this +prpic simulator so this puts together + + align:start position:0% +prpic simulator so this puts together + + + align:start position:0% +prpic simulator so this puts together +the calad thermo and Mobility databases + + align:start position:0% +the calad thermo and Mobility databases + + + align:start position:0% +the calad thermo and Mobility databases +and adds some surface theramic + + align:start position:0% +and adds some surface theramic + + + align:start position:0% +and adds some surface theramic +quantities uh to actually simulate uh + + align:start position:0% +quantities uh to actually simulate uh + + + align:start position:0% +quantities uh to actually simulate uh +complex nucleation and growth uh in + + align:start position:0% +complex nucleation and growth uh in + + + align:start position:0% +complex nucleation and growth uh in +complex Alloys uh so that we could + + align:start position:0% +complex Alloys uh so that we could + + + align:start position:0% +complex Alloys uh so that we could +actually predict the uh effects of very + + align:start position:0% +actually predict the uh effects of very + + + align:start position:0% +actually predict the uh effects of very +complex heat treatments of turban discs + + align:start position:0% +complex heat treatments of turban discs + + + align:start position:0% +complex heat treatments of turban discs +that had multimodal distributions of + + align:start position:0% +that had multimodal distributions of + + + align:start position:0% +that had multimodal distributions of +gamma Prime precipitates uh and very + + align:start position:0% +gamma Prime precipitates uh and very + + + align:start position:0% +gamma Prime precipitates uh and very +accurately control it and use it to + + align:start position:0% +accurately control it and use it to + + + align:start position:0% +accurately control it and use it to +demonstrate it in process + + align:start position:0% +demonstrate it in process + + + align:start position:0% +demonstrate it in process +optimization uh validating a predicted + + align:start position:0% +optimization uh validating a predicted + + + align:start position:0% +optimization uh validating a predicted +overspin burst speed of a of a turbine + + align:start position:0% +overspin burst speed of a of a turbine + + + align:start position:0% +overspin burst speed of a of a turbine +disc and then ultimately we did develop + + align:start position:0% +disc and then ultimately we did develop + + + align:start position:0% +disc and then ultimately we did develop +strategies to predict the cumulative + + align:start position:0% +strategies to predict the cumulative + + + align:start position:0% +strategies to predict the cumulative +probability distribution of properties + + align:start position:0% +probability distribution of properties + + + align:start position:0% +probability distribution of properties +uh from the variation that can occur uh + + align:start position:0% +uh from the variation that can occur uh + + + align:start position:0% +uh from the variation that can occur uh +from during manufacturing from the + + align:start position:0% +from during manufacturing from the + + + align:start position:0% +from during manufacturing from the +allowed tolerances of the specifications + + align:start position:0% +allowed tolerances of the specifications + + + align:start position:0% +allowed tolerances of the specifications +of material composition and processing + + align:start position:0% +of material composition and processing + + + align:start position:0% +of material composition and processing +and we were able to get information that + + align:start position:0% +and we were able to get information that + + + align:start position:0% +and we were able to get information that +normally would uh take a lot of time and + + align:start position:0% +normally would uh take a lot of time and + + + align:start position:0% +normally would uh take a lot of time and +money uh and a lot of testing like a 300 + + align:start position:0% +money uh and a lot of testing like a 300 + + + align:start position:0% +money uh and a lot of testing like a 300 +turbine disc before you'd have enough + + align:start position:0% +turbine disc before you'd have enough + + + align:start position:0% +turbine disc before you'd have enough +data and we could with only 15 data + + align:start position:0% +data and we could with only 15 data + + + align:start position:0% +data and we could with only 15 data +points and mechanistic models actually + + align:start position:0% +points and mechanistic models actually + + + align:start position:0% +points and mechanistic models actually +predict this uh 1% minimum property at + + align:start position:0% +predict this uh 1% minimum property at + + + align:start position:0% +predict this uh 1% minimum property at +room temperature and elevated + + align:start position:0% +room temperature and elevated + + + align:start position:0% +room temperature and elevated +temperature so we demonstrated the + + align:start position:0% +temperature so we demonstrated the + + + align:start position:0% +temperature so we demonstrated the +strategy to to get the qualification + + align:start position:0% +strategy to to get the qualification + + + align:start position:0% +strategy to to get the qualification +data of necessary minimum properties + + align:start position:0% +data of necessary minimum properties + + + align:start position:0% +data of necessary minimum properties +very efficiently by predictive modeling + + align:start position:0% +very efficiently by predictive modeling + + + align:start position:0% +very efficiently by predictive modeling +based on these calat + + align:start position:0% +based on these calat + + + align:start position:0% +based on these calat +tools uh and so here's the time uh chart + + align:start position:0% +tools uh and so here's the time uh chart + + + align:start position:0% +tools uh and so here's the time uh chart +on the t two uh landing gear Steels so + + align:start position:0% +on the t two uh landing gear Steels so + + + align:start position:0% +on the t two uh landing gear Steels so +this is the technology Readiness levels + + align:start position:0% +this is the technology Readiness levels + + + align:start position:0% +this is the technology Readiness levels +uh at the level of the landing gear + + align:start position:0% +uh at the level of the landing gear + + + align:start position:0% +uh at the level of the landing gear +here's the corresponding materials uh uh + + align:start position:0% +here's the corresponding materials uh uh + + + align:start position:0% +here's the corresponding materials uh uh +milestones and so both of these steals + + align:start position:0% +milestones and so both of these steals + + + align:start position:0% +milestones and so both of these steals +went from a clean sheet of paper to + + align:start position:0% +went from a clean sheet of paper to + + + align:start position:0% +went from a clean sheet of paper to +flight in less than a decade meeting the + + align:start position:0% +flight in less than a decade meeting the + + + align:start position:0% +flight in less than a decade meeting the +MGI goals uh but particularly doing it + + align:start position:0% +MGI goals uh but particularly doing it + + + align:start position:0% +MGI goals uh but particularly doing it +the second time we were able to move + + align:start position:0% +the second time we were able to move + + + align:start position:0% +the second time we were able to move +more quickly uh into the Navy trusting + + align:start position:0% +more quickly uh into the Navy trusting + + + align:start position:0% +more quickly uh into the Navy trusting +our predictions well enough to to give + + align:start position:0% +our predictions well enough to to give + + + align:start position:0% +our predictions well enough to to give +us the technology for the hook shank + + align:start position:0% +us the technology for the hook shank + + + align:start position:0% +us the technology for the hook shank +application so we actually had component + + align:start position:0% +application so we actually had component + + + align:start position:0% +application so we actually had component +qualification within a month of material + + align:start position:0% +qualification within a month of material + + + align:start position:0% +qualification within a month of material +qualification in that case and this has + + align:start position:0% +qualification in that case and this has + + + align:start position:0% +qualification in that case and this has +been a case study uh for the MGI + + align:start position:0% +been a case study uh for the MGI + + + align:start position:0% +been a case study uh for the MGI +program where uh it was reviewed in the + + align:start position:0% +program where uh it was reviewed in the + + + align:start position:0% +program where uh it was reviewed in the +second landing gear steel what were the + + align:start position:0% +second landing gear steel what were the + + + align:start position:0% +second landing gear steel what were the +technology accelerators using this + + align:start position:0% +technology accelerators using this + + + align:start position:0% +technology accelerators using this +technology and what were the Inhibitors + + align:start position:0% +technology and what were the Inhibitors + + + align:start position:0% +technology and what were the Inhibitors +uh doing it in a small business where we + + align:start position:0% +uh doing it in a small business where we + + + align:start position:0% +uh doing it in a small business where we +were uh there were lapses in the federal + + align:start position:0% +were uh there were lapses in the federal + + + align:start position:0% +were uh there were lapses in the federal +funding of the projects and there was a + + align:start position:0% +funding of the projects and there was a + + + align:start position:0% +funding of the projects and there was a +Reliance on toll manufacturing by others + + align:start position:0% +Reliance on toll manufacturing by others + + + align:start position:0% +Reliance on toll manufacturing by others +it was estimated that we had really + + align:start position:0% +it was estimated that we had really + + + align:start position:0% +it was estimated that we had really +developed uh demonstrated technology + + align:start position:0% +developed uh demonstrated technology + + + align:start position:0% +developed uh demonstrated technology +capable of a three-year cycle and that + + align:start position:0% +capable of a three-year cycle and that + + + align:start position:0% +capable of a three-year cycle and that +that's really the important key of + + align:start position:0% +that's really the important key of + + + align:start position:0% +that's really the important key of +that's what enables + + align:start position:0% +that's what enables + + + align:start position:0% +that's what enables +concurrency uh and really the uh most + + align:start position:0% +concurrency uh and really the uh most + + + align:start position:0% +concurrency uh and really the uh most +historic example of that so far uh was + + align:start position:0% +historic example of that so far uh was + + + align:start position:0% +historic example of that so far uh was +the Apple watch announced in + + align:start position:0% +the Apple watch announced in + + + align:start position:0% +the Apple watch announced in +2014 uh so these are all new Alloys + + align:start position:0% +2014 uh so these are all new Alloys + + + align:start position:0% +2014 uh so these are all new Alloys +developed by Apple uh that were uh + + align:start position:0% +developed by Apple uh that were uh + + + align:start position:0% +developed by Apple uh that were uh +designed and developed concurrently uh + + align:start position:0% +designed and developed concurrently uh + + + align:start position:0% +designed and developed concurrently uh +with the development of this device and + + align:start position:0% +with the development of this device and + + + align:start position:0% +with the development of this device and +and actually uh uh deliver in less than + + align:start position:0% +and actually uh uh deliver in less than + + + align:start position:0% +and actually uh uh deliver in less than +two years from their acquiring the + + align:start position:0% +two years from their acquiring the + + + align:start position:0% +two years from their acquiring the +technology from questech to actually do + + align:start position:0% +technology from questech to actually do + + + align:start position:0% +technology from questech to actually do +this and that included the high strength + + align:start position:0% +this and that included the high strength + + + align:start position:0% +this and that included the high strength +anodized aluminum alloy that ultimately + + align:start position:0% +anodized aluminum alloy that ultimately + + + align:start position:0% +anodized aluminum alloy that ultimately +uh went into the 6s iPhone so uh uh it's + + align:start position:0% +uh went into the 6s iPhone so uh uh it's + + + align:start position:0% +uh went into the 6s iPhone so uh uh it's +been estimated there's now a 50% chance + + align:start position:0% +been estimated there's now a 50% chance + + + align:start position:0% +been estimated there's now a 50% chance +that you've got a computationally + + align:start position:0% +that you've got a computationally + + + align:start position:0% +that you've got a computationally +designed material in your pocket uh and + + align:start position:0% +designed material in your pocket uh and + + + align:start position:0% +designed material in your pocket uh and +it came from this calipat based + + align:start position:0% +it came from this calipat based + + + align:start position:0% +it came from this calipat based +technology uh from there uh news travels + + align:start position:0% +technology uh from there uh news travels + + + align:start position:0% +technology uh from there uh news travels +fast in the valley and it the attention + + align:start position:0% +fast in the valley and it the attention + + + align:start position:0% +fast in the valley and it the attention +of this guy uh I actually had the + + align:start position:0% +of this guy uh I actually had the + + + align:start position:0% +of this guy uh I actually had the +opportunity he invited me out to give + + align:start position:0% +opportunity he invited me out to give + + + align:start position:0% +opportunity he invited me out to give +him a half hour elevator pitch uh I + + align:start position:0% +him a half hour elevator pitch uh I + + + align:start position:0% +him a half hour elevator pitch uh I +thought I was selling him our technology + + align:start position:0% +thought I was selling him our technology + + + align:start position:0% +thought I was selling him our technology +turns out I was selling him Charlie + + align:start position:0% +turns out I was selling him Charlie + + + align:start position:0% +turns out I was selling him Charlie +cumin my uh former student who was the + + align:start position:0% +cumin my uh former student who was the + + + align:start position:0% +cumin my uh former student who was the +founding uh president of CEO uh who had + + align:start position:0% +founding uh president of CEO uh who had + + + align:start position:0% +founding uh president of CEO uh who had +gone to Apple and so after three years + + align:start position:0% +gone to Apple and so after three years + + + align:start position:0% +gone to Apple and so after three years +at Apple he he moved uh uh to be vice + + align:start position:0% +at Apple he he moved uh uh to be vice + + + align:start position:0% +at Apple he he moved uh uh to be vice +president of materials technology at + + align:start position:0% +president of materials technology at + + + align:start position:0% +president of materials technology at +both SpaceX and Tesla so this Tech + + align:start position:0% +both SpaceX and Tesla so this Tech + + + align:start position:0% +both SpaceX and Tesla so this Tech +technology has been taken uh even + + align:start position:0% +technology has been taken uh even + + + align:start position:0% +technology has been taken uh even +further in that in that environment uh + + align:start position:0% +further in that in that environment uh + + + align:start position:0% +further in that in that environment uh +and uh notably + + align:start position:0% +and uh notably + + + align:start position:0% +and uh notably +included a burn resistant nickel super + + align:start position:0% +included a burn resistant nickel super + + + align:start position:0% +included a burn resistant nickel super +alloy uh that allows the high oxygen + + align:start position:0% +alloy uh that allows the high oxygen + + + align:start position:0% +alloy uh that allows the high oxygen +pressures that uh really enables the + + align:start position:0% +pressures that uh really enables the + + + align:start position:0% +pressures that uh really enables the +Raptor engine of the Mars Starship so so + + align:start position:0% +Raptor engine of the Mars Starship so so + + + align:start position:0% +Raptor engine of the Mars Starship so so +it gives you a rare example of a + + align:start position:0% +it gives you a rare example of a + + + align:start position:0% +it gives you a rare example of a +corporate CEO bragging about his + + align:start position:0% + + + + align:start position:0% + +metallurgist uh I think what I'll do is + + align:start position:0% +metallurgist uh I think what I'll do is + + + align:start position:0% +metallurgist uh I think what I'll do is +I just want to + + align:start position:0% +I just want to + + + align:start position:0% +I just want to +mention uh the back here on planet Earth + + align:start position:0% +mention uh the back here on planet Earth + + + align:start position:0% +mention uh the back here on planet Earth +we've got uh this Chad Center as a + + align:start position:0% +we've got uh this Chad Center as a + + + align:start position:0% +we've got uh this Chad Center as a +decadal center supporting the + + align:start position:0% +decadal center supporting the + + + align:start position:0% +decadal center supporting the +MGI uh it's in its second five years of + + align:start position:0% +MGI uh it's in its second five years of + + + align:start position:0% +MGI uh it's in its second five years of +of its 10 years it's a largely based in + + align:start position:0% +of its 10 years it's a largely based in + + + align:start position:0% +of its 10 years it's a largely based in +Chicago but MIT is a partner to it uh + + align:start position:0% +Chicago but MIT is a partner to it uh + + + align:start position:0% +Chicago but MIT is a partner to it uh +and it's looking at not only uh + + align:start position:0% +and it's looking at not only uh + + + align:start position:0% +and it's looking at not only uh +improving these methodologies but + + align:start position:0% +improving these methodologies but + + + align:start position:0% +improving these methodologies but +greatly expanding their scope notably + + align:start position:0% +greatly expanding their scope notably + + + align:start position:0% +greatly expanding their scope notably +incl including taking this to organic + + align:start position:0% +incl including taking this to organic + + + align:start position:0% +incl including taking this to organic +systems and polymers as as well and + + align:start position:0% +systems and polymers as as well and + + + align:start position:0% +systems and polymers as as well and +they're building out essentially a + + align:start position:0% +they're building out essentially a + + + align:start position:0% +they're building out essentially a +polymer calad uh to design all materials + + align:start position:0% +polymer calad uh to design all materials + + + align:start position:0% +polymer calad uh to design all materials +by the same + + align:start position:0% +by the same + + + align:start position:0% +by the same +methodology uh and I'll just mention + + align:start position:0% +methodology uh and I'll just mention + + + align:start position:0% +methodology uh and I'll just mention +that uh a lot of the current projects + + align:start position:0% +that uh a lot of the current projects + + + align:start position:0% +that uh a lot of the current projects +are looking specifically at the design + + align:start position:0% +are looking specifically at the design + + + align:start position:0% +are looking specifically at the design +of materials uh for the new technology + + align:start position:0% +of materials uh for the new technology + + + align:start position:0% +of materials uh for the new technology +of additive + + align:start position:0% +of additive + + + align:start position:0% +of additive +manufacturing uh and here's a some of + + align:start position:0% +manufacturing uh and here's a some of + + + align:start position:0% +manufacturing uh and here's a some of +the early projects at quc in that field + + align:start position:0% +the early projects at quc in that field + + + align:start position:0% +the early projects at quc in that field +and one of our more important designs + + align:start position:0% +and one of our more important designs + + + align:start position:0% +and one of our more important designs +was a high temperature aluminum that + + align:start position:0% +was a high temperature aluminum that + + + align:start position:0% +was a high temperature aluminum that +uses unique features of additive + + align:start position:0% +uses unique features of additive + + + align:start position:0% +uses unique features of additive +manufacturing that compared to this + + align:start position:0% +manufacturing that compared to this + + + align:start position:0% +manufacturing that compared to this +Scandium bearing alloy we have Scandium + + align:start position:0% +Scandium bearing alloy we have Scandium + + + align:start position:0% +Scandium bearing alloy we have Scandium +free Alloys using some Rare Earth + + align:start position:0% +free Alloys using some Rare Earth + + + align:start position:0% +free Alloys using some Rare Earth +elements uh that are able to sustain + + align:start position:0% +elements uh that are able to sustain + + + align:start position:0% +elements uh that are able to sustain +high strength in aluminum alloy out to + + align:start position:0% +high strength in aluminum alloy out to + + + align:start position:0% +high strength in aluminum alloy out to +very high temperatures very promising + + align:start position:0% +very high temperatures very promising + + + align:start position:0% +very high temperatures very promising +and it's a unique microstructure that + + align:start position:0% +and it's a unique microstructure that + + + align:start position:0% +and it's a unique microstructure that +can only be achieved by additive + + align:start position:0% +can only be achieved by additive + + + align:start position:0% +can only be achieved by additive +manufacturing um did want to mention uh + + align:start position:0% +manufacturing um did want to mention uh + + + align:start position:0% +manufacturing um did want to mention uh +electroceramic we had the opportunity + + align:start position:0% +electroceramic we had the opportunity + + + align:start position:0% +electroceramic we had the opportunity +under this DARPA Simplex program we were + + align:start position:0% +under this DARPA Simplex program we were + + + align:start position:0% +under this DARPA Simplex program we were +asked by DARPA to look at integrating + + align:start position:0% +asked by DARPA to look at integrating + + + align:start position:0% +asked by DARPA to look at integrating +new uh data mining techniques with our + + align:start position:0% +new uh data mining techniques with our + + + align:start position:0% +new uh data mining techniques with our +calad based design strategy and apply it + + align:start position:0% +calad based design strategy and apply it + + + align:start position:0% +calad based design strategy and apply it +specifically to thermoelectric systems + + align:start position:0% +specifically to thermoelectric systems + + + align:start position:0% +specifically to thermoelectric systems +uh so here uh this is the system chart + + align:start position:0% +uh so here uh this is the system chart + + + align:start position:0% +uh so here uh this is the system chart +uh for a thermoelectric material where + + align:start position:0% +uh for a thermoelectric material where + + + align:start position:0% +uh for a thermoelectric material where +the basic conflict is we want electrical + + align:start position:0% +the basic conflict is we want electrical + + + align:start position:0% +the basic conflict is we want electrical +conductivity but not thermal + + align:start position:0% +conductivity but not thermal + + + align:start position:0% +conductivity but not thermal +conductivity and the way to break that + + align:start position:0% +conductivity and the way to break that + + + align:start position:0% +conductivity and the way to break that +uh is to use micr structure for phonon + + align:start position:0% +uh is to use micr structure for phonon + + + align:start position:0% +uh is to use micr structure for phonon +scattering uh to get the + + align:start position:0% +scattering uh to get the + + + align:start position:0% +scattering uh to get the +thermoconductivity down so it was a + + align:start position:0% +thermoconductivity down so it was a + + + align:start position:0% +thermoconductivity down so it was a +chance to use the same kind of + + align:start position:0% +chance to use the same kind of + + + align:start position:0% +chance to use the same kind of +hierarchical uh micr structures that we + + align:start position:0% +hierarchical uh micr structures that we + + + align:start position:0% +hierarchical uh micr structures that we +use in structural Alloys of + + align:start position:0% +use in structural Alloys of + + + align:start position:0% +use in structural Alloys of +precipitation and grain refinement uh to + + align:start position:0% +precipitation and grain refinement uh to + + + align:start position:0% +precipitation and grain refinement uh to +manage the thermoconductivity and one + + align:start position:0% +manage the thermoconductivity and one + + + align:start position:0% +manage the thermoconductivity and one +early example of that was to build out + + align:start position:0% +early example of that was to build out + + + align:start position:0% +early example of that was to build out +the calad Thermon namics of this lead + + align:start position:0% +the calad Thermon namics of this lead + + + align:start position:0% +the calad Thermon namics of this lead +toride lead sulfide system uh taking the + + align:start position:0% +toride lead sulfide system uh taking the + + + align:start position:0% +toride lead sulfide system uh taking the +same framework uh and then actually + + align:start position:0% +same framework uh and then actually + + + align:start position:0% +same framework uh and then actually +predict from a phonon scattering model + + align:start position:0% +predict from a phonon scattering model + + + align:start position:0% +predict from a phonon scattering model +uh if we optimize the particle size + + align:start position:0% +uh if we optimize the particle size + + + align:start position:0% +uh if we optimize the particle size +uh what level of performance we could + + align:start position:0% +uh what level of performance we could + + + align:start position:0% +uh what level of performance we could +achieve as we vary the phase fraction of + + align:start position:0% +achieve as we vary the phase fraction of + + + align:start position:0% +achieve as we vary the phase fraction of +the lead sulfide particles and it showed + + align:start position:0% +the lead sulfide particles and it showed + + + align:start position:0% +the lead sulfide particles and it showed +that it agreed with the data from + + align:start position:0% +that it agreed with the data from + + + align:start position:0% +that it agreed with the data from +empirical development literature at low + + align:start position:0% +empirical development literature at low + + + align:start position:0% +empirical development literature at low +phase fractions but actually said at + + align:start position:0% +phase fractions but actually said at + + + align:start position:0% +phase fractions but actually said at +these higher phase fractions uh if we + + align:start position:0% +these higher phase fractions uh if we + + + align:start position:0% +these higher phase fractions uh if we +were to refine the particles to their + + align:start position:0% +were to refine the particles to their + + + align:start position:0% +were to refine the particles to their +Optimum size there is more performance + + align:start position:0% +Optimum size there is more performance + + + align:start position:0% +Optimum size there is more performance +that you could achieve from that system + + align:start position:0% +that you could achieve from that system + + + align:start position:0% +that you could achieve from that system +so this is a very early uh demo of + + align:start position:0% +so this is a very early uh demo of + + + align:start position:0% +so this is a very early uh demo of +applying calad to these systems as well + + align:start position:0% +applying calad to these systems as well + + + align:start position:0% +applying calad to these systems as well +uh and this is underway now uh in as + + align:start position:0% +uh and this is underway now uh in as + + + align:start position:0% +uh and this is underway now uh in as +part of the Chad Jeff Snider at + + align:start position:0% +part of the Chad Jeff Snider at + + + align:start position:0% +part of the Chad Jeff Snider at +Northwestern is actively developing uh + + align:start position:0% +Northwestern is actively developing uh + + + align:start position:0% +Northwestern is actively developing uh +the use of the calad tools uh to control + + align:start position:0% +the use of the calad tools uh to control + + + align:start position:0% +the use of the calad tools uh to control +predictively control microstructure + + align:start position:0% +predictively control microstructure + + + align:start position:0% +predictively control microstructure +optimization in these same systems but + + align:start position:0% +optimization in these same systems but + + + align:start position:0% +optimization in these same systems but +of course what you really want to know + + align:start position:0% +of course what you really want to know + + + align:start position:0% +of course what you really want to know +is what about bubble gum and so uh we + + align:start position:0% +is what about bubble gum and so uh we + + + align:start position:0% +is what about bubble gum and so uh we +did get support uh from Wrigley uh did + + align:start position:0% +did get support uh from Wrigley uh did + + + align:start position:0% +did get support uh from Wrigley uh did +have four years of support for a doctor + + align:start position:0% +have four years of support for a doctor + + + align:start position:0% +have four years of support for a doctor +of bubble gum uh and we were asked to uh + + align:start position:0% +of bubble gum uh and we were asked to uh + + + align:start position:0% +of bubble gum uh and we were asked to uh +uh make a four component uh easy to + + align:start position:0% +uh make a four component uh easy to + + + align:start position:0% +uh make a four component uh easy to +manufacture uh gum similar to uh Hubba + + align:start position:0% +manufacture uh gum similar to uh Hubba + + + align:start position:0% +manufacture uh gum similar to uh Hubba +Bubba seriously strawberry uh could we + + align:start position:0% +Bubba seriously strawberry uh could we + + + align:start position:0% +Bubba seriously strawberry uh could we +with that simple a formula get the + + align:start position:0% +with that simple a formula get the + + + align:start position:0% +with that simple a formula get the +performance level of uh Hubba Bubba Max + + align:start position:0% +performance level of uh Hubba Bubba Max + + + align:start position:0% +performance level of uh Hubba Bubba Max +which is the highest performance + + align:start position:0% +which is the highest performance + + + align:start position:0% +which is the highest performance +commercial bubble gum but very difficult + + align:start position:0% +commercial bubble gum but very difficult + + + align:start position:0% +commercial bubble gum but very difficult +to manufacture and we did succeed uh + + align:start position:0% +to manufacture and we did succeed uh + + + align:start position:0% +to manufacture and we did succeed uh +with our modeling to uh even outperform + + align:start position:0% +with our modeling to uh even outperform + + + align:start position:0% +with our modeling to uh even outperform +uh the highest performance gum out there + + align:start position:0% +uh the highest performance gum out there + + + align:start position:0% +uh the highest performance gum out there +so we had finally had produced material + + align:start position:0% +so we had finally had produced material + + + align:start position:0% +so we had finally had produced material +that Society could appreciate it was + + align:start position:0% +that Society could appreciate it was + + + align:start position:0% +that Society could appreciate it was +very rewarding and this was aided by a + + align:start position:0% +very rewarding and this was aided by a + + + align:start position:0% +very rewarding and this was aided by a +student team that actually won the ASM + + align:start position:0% +student team that actually won the ASM + + + align:start position:0% +student team that actually won the ASM +design competition back in + + align:start position:0% +design competition back in + + + align:start position:0% +design competition back in +2008 and if you'd like to learn more + + align:start position:0% +2008 and if you'd like to learn more + + + align:start position:0% +2008 and if you'd like to learn more +about that I suggest you sign up uh next + + align:start position:0% +about that I suggest you sign up uh next + + + align:start position:0% +about that I suggest you sign up uh next +year for uh 3041 and learn how to be a + + align:start position:0% +year for uh 3041 and learn how to be a + + + align:start position:0% +year for uh 3041 and learn how to be a +materials designer here's an example of + + align:start position:0% +materials designer here's an example of + + + align:start position:0% +materials designer here's an example of +the five projects currently underway uh + + align:start position:0% +the five projects currently underway uh + + + align:start position:0% +the five projects currently underway uh +all of these connect back to the chime + + align:start position:0% +all of these connect back to the chime + + + align:start position:0% +all of these connect back to the chime +ad research so uh the teams identified + + align:start position:0% +ad research so uh the teams identified + + + align:start position:0% +ad research so uh the teams identified +in R here are all being coached by uh + + align:start position:0% +in R here are all being coached by uh + + + align:start position:0% +in R here are all being coached by uh +doctoral students and postdocs uh whose + + align:start position:0% +doctoral students and postdocs uh whose + + + align:start position:0% +doctoral students and postdocs uh whose +thesis is on that particular design + + align:start position:0% +thesis is on that particular design + + + align:start position:0% +thesis is on that particular design +project to help student teams uh get to + + align:start position:0% +project to help student teams uh get to + + + align:start position:0% +project to help student teams uh get to +the high technical level it uh takes to + + align:start position:0% +the high technical level it uh takes to + + + align:start position:0% +the high technical level it uh takes to +actually do the computational design of + + align:start position:0% +actually do the computational design of + + + align:start position:0% +actually do the computational design of +a complete material with some + + align:start position:0% +a complete material with some + + + align:start position:0% +a complete material with some +challenging objectives uh notably + + align:start position:0% +challenging objectives uh notably + + + align:start position:0% +challenging objectives uh notably +including a project this year that uh + + align:start position:0% +including a project this year that uh + + + align:start position:0% +including a project this year that uh +where apple is the uh client uh and + + align:start position:0% +where apple is the uh client uh and + + + align:start position:0% +where apple is the uh client uh and +we've had a number of students uh coming + + align:start position:0% +we've had a number of students uh coming + + + align:start position:0% +we've had a number of students uh coming +out of the class who have gone to take + + align:start position:0% +out of the class who have gone to take + + + align:start position:0% +out of the class who have gone to take +internships over the summer at Apple + + align:start position:0% +internships over the summer at Apple + + + align:start position:0% +internships over the summer at Apple +they're very pleased with the + + align:start position:0% +they're very pleased with the + + + align:start position:0% +they're very pleased with the +students so I highly recommend you sign + + align:start position:0% +students so I highly recommend you sign + + + align:start position:0% +students so I highly recommend you sign +up and join us next + + align:start position:0% + + + + align:start position:0% + +year all right well that was fantastic + + align:start position:0% +year all right well that was fantastic + + + align:start position:0% +year all right well that was fantastic +that covered a lot of ground Greg and + + align:start position:0% +that covered a lot of ground Greg and + + + align:start position:0% +that covered a lot of ground Greg and +and we're right on time so I hope it + + align:start position:0% +and we're right on time so I hope it + + + align:start position:0% +and we're right on time so I hope it +wasn't too dizzying but of course you + + align:start position:0% +wasn't too dizzying but of course you + + + align:start position:0% +wasn't too dizzying but of course you +have the opportunity to go back and play + + align:start position:0% +have the opportunity to go back and play + + + align:start position:0% +have the opportunity to go back and play +it over and slow me + + align:start position:0% +it over and slow me + + + align:start position:0% +it over and slow me +down it was dizzying but it was a really + + align:start position:0% +down it was dizzying but it was a really + + + align:start position:0% +down it was dizzying but it was a really +impressive show of impact so thank you + + align:start position:0% +impressive show of impact so thank you + + + align:start position:0% +impressive show of impact so thank you +we have um so as usual I'm going + + align:start position:0% +we have um so as usual I'm going + + + align:start position:0% +we have um so as usual I'm going +to uh stop recording in a minute but I'm + + align:start position:0% +to uh stop recording in a minute but I'm + + + align:start position:0% +to uh stop recording in a minute but I'm +very happy to take questions or I'm sure + + align:start position:0% +very happy to take questions or I'm sure + + + align:start position:0% +very happy to take questions or I'm sure +Greg is happy to take questions for a + + align:start position:0% +Greg is happy to take questions for a + + + align:start position:0% +Greg is happy to take questions for a +couple minutes indeed till the bottom of + + align:start position:0% +couple minutes indeed till the bottom of + + + align:start position:0% +couple minutes indeed till the bottom of +the + + align:start position:0% +the + + + align:start position:0% +the +hour + + align:start position:0% +hour + + + align:start position:0% +hour +um know questions about calad the + + align:start position:0% +um know questions about calad the + + + align:start position:0% +um know questions about calad the +mechanism the history the the science + + align:start position:0% +mechanism the history the the science + + + align:start position:0% +mechanism the history the the science +landing gear Elon + + align:start position:0% +landing gear Elon + + + align:start position:0% +landing gear Elon +Musk I'm + + align:start position:0% +Musk I'm + + + align:start position:0% +Musk I'm +sure did did you know how important this + + align:start position:0% +sure did did you know how important this + + + align:start position:0% +sure did did you know how important this +was did to your well to your your modern + + align:start position:0% +was did to your well to your your modern + + + align:start position:0% +was did to your well to your your modern +lives even in your + + align:start position:0% + + + + align:start position:0% + +iPhone and it will help reduce it will + + align:start position:0% +iPhone and it will help reduce it will + + + align:start position:0% +iPhone and it will help reduce it will +help reduce the price of your Mars + + align:start position:0% +help reduce the price of your Mars + + + align:start position:0% +help reduce the price of your Mars +ticket too the efficiency of the engine + + align:start position:0% +ticket too the efficiency of the engine + + + align:start position:0% +ticket too the efficiency of the engine +yeah the models uh that worked with like + + align:start position:0% +yeah the models uh that worked with like + + + align:start position:0% +yeah the models uh that worked with like +the heat that worked with the heat + + align:start position:0% +the heat that worked with the heat + + + align:start position:0% +the heat that worked with the heat +transfer from other uh companies I think + + align:start position:0% +transfer from other uh companies I think + + + align:start position:0% +transfer from other uh companies I think +you said were working with U I just know + + align:start position:0% +you said were working with U I just know + + + align:start position:0% +you said were working with U I just know +Air Force or ster that uh you + + align:start position:0% +Air Force or ster that uh you + + + align:start position:0% +Air Force or ster that uh you +collaborated with uh other engineering + + align:start position:0% +collaborated with uh other engineering + + + align:start position:0% +collaborated with uh other engineering +yeah so companies right so the idea of + + align:start position:0% +yeah so companies right so the idea of + + + align:start position:0% +yeah so companies right so the idea of +ICM is to link the materials models to + + align:start position:0% +ICM is to link the materials models to + + + align:start position:0% +ICM is to link the materials models to +the macroscopic processing tools where + + align:start position:0% +the macroscopic processing tools where + + + align:start position:0% +the macroscopic processing tools where +very often it's all about the heat + + align:start position:0% +very often it's all about the heat + + + align:start position:0% +very often it's all about the heat +transfer so we were uh in the aim + + align:start position:0% +transfer so we were uh in the aim + + + align:start position:0% +transfer so we were uh in the aim +project we were able to then uh simulate + + align:start position:0% +project we were able to then uh simulate + + + align:start position:0% +project we were able to then uh simulate +the heat transfer the the the actual + + align:start position:0% +the heat transfer the the the actual + + + align:start position:0% +the heat transfer the the the actual +thermal processing of a turban disc uh + + align:start position:0% +thermal processing of a turban disc uh + + + align:start position:0% +thermal processing of a turban disc uh +and then take the thermal history at + + align:start position:0% +and then take the thermal history at + + + align:start position:0% +and then take the thermal history at +different nodes in that simulation uh + + align:start position:0% +different nodes in that simulation uh + + + align:start position:0% +different nodes in that simulation uh +and simulate its full evolution of its + + align:start position:0% +and simulate its full evolution of its + + + align:start position:0% +and simulate its full evolution of its +complex micr structure uh through uh + + align:start position:0% +complex micr structure uh through uh + + + align:start position:0% +complex micr structure uh through uh +that complex uh processing uh and + + align:start position:0% +that complex uh processing uh and + + + align:start position:0% +that complex uh processing uh and +actually predict the spatial variation + + align:start position:0% +actually predict the spatial variation + + + align:start position:0% +actually predict the spatial variation +in the turban dis of uh structure and + + align:start position:0% +in the turban dis of uh structure and + + + align:start position:0% +in the turban dis of uh structure and +properties uh with an accuracy within + + align:start position:0% +properties uh with an accuracy within + + + align:start position:0% +properties uh with an accuracy within +one KSI in the yield + + align:start position:0% +one KSI in the yield + + + align:start position:0% +one KSI in the yield +string what's the models employed by + + align:start position:0% +string what's the models employed by + + + align:start position:0% +string what's the models employed by +inle uh mechan like this mechanical + + align:start position:0% +inle uh mechan like this mechanical + + + align:start position:0% +inle uh mechan like this mechanical +engineering uh uh like like compatible + + align:start position:0% +engineering uh uh like like compatible + + + align:start position:0% +engineering uh uh like like compatible +with the material + + align:start position:0% +with the material + + + align:start position:0% +with the material +models in terms of like the math or + + align:start position:0% +models in terms of like the math or + + + align:start position:0% +models in terms of like the math or +continuity of that stuff yeah well + + align:start position:0% +continuity of that stuff yeah well + + + align:start position:0% +continuity of that stuff yeah well +that's the role of that eyesight uh + + align:start position:0% +that's the role of that eyesight uh + + + align:start position:0% +that's the role of that eyesight uh +process integration and design + + align:start position:0% +process integration and design + + + align:start position:0% +process integration and design +optimization software so there are + + align:start position:0% +optimization software so there are + + + align:start position:0% +optimization software so there are +integration tools like that that are + + align:start position:0% +integration tools like that that are + + + align:start position:0% +integration tools like that that are +intended to connect models from any + + align:start position:0% +intended to connect models from any + + + align:start position:0% +intended to connect models from any +software on any platform and be able to + + align:start position:0% +software on any platform and be able to + + + align:start position:0% +software on any platform and be able to +transfer the output of one as the input + + align:start position:0% +transfer the output of one as the input + + + align:start position:0% +transfer the output of one as the input +to + + align:start position:0% +to + + + align:start position:0% +to +another and I'll say this is um this + + align:start position:0% +another and I'll say this is um this + + + align:start position:0% +another and I'll say this is um this +sort of integration is + + align:start position:0% +sort of integration is + + + align:start position:0% +sort of integration is +um it's part of what you're doing on + + align:start position:0% +um it's part of what you're doing on + + + align:start position:0% +um it's part of what you're doing on +this on not not P at um seven but um P + + align:start position:0% +this on not not P at um seven but um P + + + align:start position:0% +this on not not P at um seven but um P +at 8 which is you know you have software + + align:start position:0% +at 8 which is you know you have software + + + align:start position:0% +at 8 which is you know you have software +and it has data and it outputs some form + + align:start position:0% +and it has data and it outputs some form + + + align:start position:0% +and it has data and it outputs some form +of data and you want to model that so + + align:start position:0% +of data and you want to model that so + + + align:start position:0% +of data and you want to model that so +that you could perhaps use it in a + + align:start position:0% +that you could perhaps use it in a + + + align:start position:0% +that you could perhaps use it in a +different piece of software you know and + + align:start position:0% +different piece of software you know and + + + align:start position:0% +different piece of software you know and +um you know you're doing this uh today + + align:start position:0% +um you know you're doing this uh today + + + align:start position:0% +um you know you're doing this uh today +you know you you're doing this I would + + align:start position:0% +you know you you're doing this I would + + + align:start position:0% +you know you you're doing this I would +in a sense a very low level down in the + + align:start position:0% +in a sense a very low level down in the + + + align:start position:0% +in a sense a very low level down in the +weeds looking at you know a couple + + align:start position:0% +weeds looking at you know a couple + + + align:start position:0% +weeds looking at you know a couple +traces of data but you know once you + + align:start position:0% +traces of data but you know once you + + + align:start position:0% +traces of data but you know once you +understand the sort of things that + + align:start position:0% +understand the sort of things that + + + align:start position:0% +understand the sort of things that +happened down in the weeds you can start + + align:start position:0% +happened down in the weeds you can start + + + align:start position:0% +happened down in the weeds you can start +to step back and look at a bigger + + align:start position:0% +to step back and look at a bigger + + + align:start position:0% +to step back and look at a bigger +picture and imagine more sophisticated + + align:start position:0% +picture and imagine more sophisticated + + + align:start position:0% +picture and imagine more sophisticated +integration so it's it's it's great that + + align:start position:0% +integration so it's it's it's great that + + + align:start position:0% +integration so it's it's it's great that +you brought that + + align:start position:0% +you brought that + + + align:start position:0% +you brought that +up yeah and of course that that is all a + + align:start position:0% +up yeah and of course that that is all a + + + align:start position:0% +up yeah and of course that that is all a +very important part of this concurrent + + align:start position:0% +very important part of this concurrent + + + align:start position:0% +very important part of this concurrent +engineering approach that we can + + align:start position:0% +engineering approach that we can + + + align:start position:0% +engineering approach that we can +actually link the computational tools + + align:start position:0% +actually link the computational tools + + + align:start position:0% +actually link the computational tools +across disciplines and uh simulate the + + align:start position:0% +across disciplines and uh simulate the + + + align:start position:0% +across disciplines and uh simulate the +system level so I guess going going off + + align:start position:0% +system level so I guess going going off + + + align:start position:0% +system level so I guess going going off +of that you mentioned a few times how + + align:start position:0% +of that you mentioned a few times how + + + align:start position:0% +of that you mentioned a few times how +now with all the new technologies and + + align:start position:0% +now with all the new technologies and + + + align:start position:0% +now with all the new technologies and +methods of sort of understanding + + align:start position:0% +methods of sort of understanding + + + align:start position:0% +methods of sort of understanding +materials work how now there's a lot + + align:start position:0% +materials work how now there's a lot + + + align:start position:0% +materials work how now there's a lot +more concurrent engineering taking place + + align:start position:0% +more concurrent engineering taking place + + + align:start position:0% +more concurrent engineering taking place +sort of how the materials are being + + align:start position:0% +sort of how the materials are being + + + align:start position:0% +sort of how the materials are being +developed alongside the the products + + align:start position:0% +developed alongside the the products + + + align:start position:0% +developed alongside the the products +that are going out to Market or for + + align:start position:0% +that are going out to Market or for + + + align:start position:0% +that are going out to Market or for +consumers to use and I was wondering how + + align:start position:0% +consumers to use and I was wondering how + + + align:start position:0% +consumers to use and I was wondering how +tied those two things are like if if you + + align:start position:0% +tied those two things are like if if you + + + align:start position:0% +tied those two things are like if if you +know if there are like different teams + + align:start position:0% +know if there are like different teams + + + align:start position:0% +know if there are like different teams +working on different aspects of it or if + + align:start position:0% +working on different aspects of it or if + + + align:start position:0% +working on different aspects of it or if +it's really becoming more and more + + align:start position:0% +it's really becoming more and more + + + align:start position:0% +it's really becoming more and more +integrated in terms of like the + + align:start position:0% +integrated in terms of like the + + + align:start position:0% +integrated in terms of like the +production + + align:start position:0% +production + + + align:start position:0% +production +teams yeah uh I I would say there there + + align:start position:0% +teams yeah uh I I would say there there + + + align:start position:0% +teams yeah uh I I would say there there +is ever increasing integration + + align:start position:0% +is ever increasing integration + + + align:start position:0% +is ever increasing integration +uh and of course in the case of Apple + + align:start position:0% +uh and of course in the case of Apple + + + align:start position:0% +uh and of course in the case of Apple +these really are consumer products that + + align:start position:0% +these really are consumer products that + + + align:start position:0% +these really are consumer products that +they're uh and very novel products that + + align:start position:0% +they're uh and very novel products that + + + align:start position:0% +they're uh and very novel products that +they are developing on a very + + align:start position:0% +they are developing on a very + + + align:start position:0% +they are developing on a very +accelerated schedule but uh what they're + + align:start position:0% +accelerated schedule but uh what they're + + + align:start position:0% +accelerated schedule but uh what they're +very good at is the manufacturing + + align:start position:0% +very good at is the manufacturing + + + align:start position:0% +very good at is the manufacturing +engineer because they make stuff on such + + align:start position:0% +engineer because they make stuff on such + + + align:start position:0% +engineer because they make stuff on such +a huge scale uh so they're very good at + + align:start position:0% +a huge scale uh so they're very good at + + + align:start position:0% +a huge scale uh so they're very good at +that I think at SpaceX you're seeing uh + + align:start position:0% +that I think at SpaceX you're seeing uh + + + align:start position:0% +that I think at SpaceX you're seeing uh +very Innovative technology uh so the + + align:start position:0% +very Innovative technology uh so the + + + align:start position:0% +very Innovative technology uh so the +early ideation of taking extremely + + align:start position:0% +early ideation of taking extremely + + + align:start position:0% +early ideation of taking extremely +challenging problems like how we get + + align:start position:0% +challenging problems like how we get + + + align:start position:0% +challenging problems like how we get +humans to Mars efficiently + + align:start position:0% +humans to Mars efficiently + + + align:start position:0% +humans to Mars efficiently +uh is making maximum use of this and and + + align:start position:0% +uh is making maximum use of this and and + + + align:start position:0% +uh is making maximum use of this and and +uh there it's it's a very thorough + + align:start position:0% +uh there it's it's a very thorough + + + align:start position:0% +uh there it's it's a very thorough +integration at all levels uh so they use + + align:start position:0% +integration at all levels uh so they use + + + align:start position:0% +integration at all levels uh so they use +this the so-called 80% solution that uh + + align:start position:0% +this the so-called 80% solution that uh + + + align:start position:0% +this the so-called 80% solution that uh +uh it's often said that uh with h with + + align:start position:0% +uh it's often said that uh with h with + + + align:start position:0% +uh it's often said that uh with h with +20 in computation with 20% of the + + align:start position:0% +20 in computation with 20% of the + + + align:start position:0% +20 in computation with 20% of the +resources you can get 80% of the way + + align:start position:0% +resources you can get 80% of the way + + + align:start position:0% +resources you can get 80% of the way +where you're trying to go and then the + + align:start position:0% +where you're trying to go and then the + + + align:start position:0% +where you're trying to go and then the +question is do you really want to spend + + align:start position:0% +question is do you really want to spend + + + align:start position:0% +question is do you really want to spend +the next 80% to only get another 20% uh + + align:start position:0% +the next 80% to only get another 20% uh + + + align:start position:0% +the next 80% to only get another 20% uh +so pretty much at all levels of + + align:start position:0% +so pretty much at all levels of + + + align:start position:0% +so pretty much at all levels of +structure they'll take the computation + + align:start position:0% +structure they'll take the computation + + + align:start position:0% +structure they'll take the computation +to 80% for everything including + + align:start position:0% +to 80% for everything including + + + align:start position:0% +to 80% for everything including +materials now uh and then of course they + + align:start position:0% +materials now uh and then of course they + + + align:start position:0% +materials now uh and then of course they +blow up rockets at SpaceX and those are + + align:start position:0% +blow up rockets at SpaceX and those are + + + align:start position:0% +blow up rockets at SpaceX and those are +highly instrumented blowing up rockets + + align:start position:0% +highly instrumented blowing up rockets + + + align:start position:0% +highly instrumented blowing up rockets +and that the idea is to test it the full + + align:start position:0% +and that the idea is to test it the full + + + align:start position:0% +and that the idea is to test it the full +system level and approach full system + + align:start position:0% +system level and approach full system + + + align:start position:0% +system level and approach full system +level + + align:start position:0% +level + + + align:start position:0% +level +optimization uh taking everything to its + + align:start position:0% +optimization uh taking everything to its + + + align:start position:0% +optimization uh taking everything to its +limits instrumented so they can dial it + + align:start position:0% +limits instrumented so they can dial it + + + align:start position:0% +limits instrumented so they can dial it +back on on the next one uh but the pace + + align:start position:0% +back on on the next one uh but the pace + + + align:start position:0% +back on on the next one uh but the pace +at which they're able to do this is + + align:start position:0% +at which they're able to do this is + + + align:start position:0% +at which they're able to do this is +really incredible by integrating across + + align:start position:0% +really incredible by integrating across + + + align:start position:0% +really incredible by integrating across +all those disciplines \ No newline at end of file diff --git a/APv1uyLL6ok.txt b/APv1uyLL6ok.txt new file mode 100644 index 0000000000000000000000000000000000000000..2e7c667615b86ccdef91a1a19a7a26c61d68953f --- /dev/null +++ b/APv1uyLL6ok.txt @@ -0,0 +1,2492 @@ +PROFESSOR: All right, my trusty +$5 Timex watch says + +it's five after the hour. + +So I guess we might +as well begin. + +I have corrected all the +problems that were turned in-- + +the puzzles, not problems, +puzzles. + +And I just yesterday +got hold of the + +photographs of you few people. + +And I'd like to hand out the +papers individually so I can + +start to put names together +with faces. + +So I'll turn them back +individually next time. + +I have one additional problem +set that for you. + +And again, this is in the +form of a puzzle. + +Be assured that this is the last +entertaining problem set. + +From here on, we move +into drudgery-- + +tedious, drawn out things +that hopefully + +will teach you something. + +But this is the last one that's +done with a little bit + +of tongue in cheek humor. + +This one is a little more subtle +than the other two. + +And for this one, I will hand +out a solution because I would + +like to use these problems to +make a couple of basic points + +about the nature of symmetry +theory in crystals. + +So see how you do on this one. + +OK, also before we begin, he +gets a little bit uneasy + +before a crowd. + +But I brought a little friend +in with me today. + +And could someone hold +the box, please, so I + +could take him out? + +Sorry. + +He gets a little bit nervous +before a crowd. + +Come on, take it easy. + +Take it easy. + +This is Rodney. + +He's an old friend of mine. + +Rodney is a crystallographic +abomination. + +Rodney has five-fold +symmetry-- + +impossible in crystallography, +an abomination. + +Why did Rodney decide +to do this? + +Anybody have any idea? + +Why not six fold symmetry? + +He's got five-fold symmetry. + +Yuck! + +But why? + +There's always a reason for +things if you look carefully + +enough and know what +questions to ask. + +Yeah? + +AUDIENCE: He had narrow +symmetry. + +PROFESSOR: Yeah, he had +narrow symmetry. + +But he could do that-- what +if you were square? + +Why not a square starfish? + +Why five? + +He did this for a reason. + +He's been doing this for +probably a couple of million + +years, he and his ancestors. + +There has to be a reason. + +OK, let me turn him over. + +And maybe that will +give you a clue. + +The backside is not nearly as +nice as the front side. + +And in fact, if you look at +Rodney carefully, Rodney has + +sutures between these +five arms. + +OK, this is what he looks +like from the top. + +But if you look at him from the +bottom, there are sutures + +between these arms +that do this. + +And these sutures are weak +points in his structure. + +And by having five-fold +symmetry, he puts the suture + +between this pair of arms +opposite the midpoint of the + +opposite rib. + +And that gives him a great deal + +more structural integrity. + +So when a large fish comes along +and gloms onto one of + +his arms and shakes, he doesn't +split in half and end + +his career prematurely. + +What happens instead, at very +worst, the tip of the arm + +breaks off. + +And then, Rodney gets to scamper +away and make more + +starfish or do whatever his +purpose in our environment is. + +If he had an even-fold +symmetry, + +that wouldn't happen. + +He would really be +done in by a fish + +grabbing hold and shaking. + +AUDIENCE: What if [INAUDIBLE]? + +PROFESSOR: That's a very +good question. + +If he had only three arms and +a fish glomed on and one arm + +broke off, his mobility would +be greatly impaired. + +In a way, he would go +hip, hop, flop. + +Hip, hip, flop. + +Hip, hip, flop. + +Hip, hip, flop. + +It'd be a pathetic thing. + +So five is much more +advantageous than three. + +AUDIENCE: Why not seven? + +PROFESSOR: Why not seven? + +That's a good question, too. + +Would you believe that on the +Australian Barrier Reef, there + +are starfish with nine-fold +symmetry? + +Quite odd. + +That's really a creepy +thing with all those + +arms flopping around. + +But as many things in our +environment in our natural + +world, there's a reason for +things if you can only think + +what it might be. + +So we gave you another example +of a non-crystallographic + +symmetry, the large cacti of the +Southwest, the saguaros. + +And there are lots of +other ribbed casts. + +They have symmetries that range +between 19 and 23 fold. + +Why do you think they have +this rib structure? + +Why can't they have a +nice, smooth trunk + +like a birch tree? + +Any idea there? + +I'll give you a hint. + +They live out in the desert. + +There's not much water. + +AUDIENCE: [INAUDIBLE]. + +PROFESSOR: Hm? + +AUDIENCE: More surface area +for the [INAUDIBLE]. + +PROFESSOR: Yeah, +but that's bad. + +That means they would +lose their water. + +So things that don't +want to lose water + +through their surface-- + +you're right-- try to minimize +their surface. + +But you're onto something. + +And it is exactly the +reverse of that. + +Water is scarce. + +So when it rains, this cactus +wants to soak up the moisture + +and store it. + +If he has this pleated +structure, + +he's able to expand. + +If he had a smooth surface +with minimal area, + +he would just pop. + +And that would be the end of +him or her, as the case may + +be. "It" is probably the +appropriate term. + +But anyway, there's the reason +for these many, many ribs. + +It gives them the ability to +expand, store water, and then + +contract when the water +evaporates. + +So again, it's always +interesting to look at the + +world around us and see examples +of things that are + +strange because it's the strange +things that very often + +can lead to penetrating +conclusions. + +All right, last time we had +talked about chirality in + +finite atomic structures, +molecules. + +And I had pointed out-- but +did not make the obvious + +observation-- + +I cannot think of a more +dramatic connection between + +structure and properties, which +is what material science + +is all about, than the very, +very different properties of + +molecules that are of +opposite handedness. + +We pointed out, for example, +that many pharmaceuticals are + +of chiral molecules that exist +in right handed and left + +handed forms. + +And very often, one form of +one handedness has a very + +different set of properties, +and in particular + +pharmacological action, then +it it's enan enantiomorph. + +So in the case of thalidomide, +one handedness of the molecule + +acts as a tranquilizer. + +The other handedness acts as +a source of birth defects. + +One of the other ones less +familiar to me, but this is + +[? ethambutol. ?] + +It's used as a drug to +treat tuberculosis. + +The molecule of opposite +handedness creates blindness. + +The drug Ritalin that is used +to treat hyperactivity, one + +handedness of the molecule +is absolutely useless. + +So you only use half of +what you pay for. + +So it's of great interest to +pharmaceutical companies to be + +able to synthesize a molecule +of one particular handedness + +with little if none +of the other one. + +And I looked up a number +since we met last time. + +It turns out that in 1997, +enantiomorph pure drugs were a + +$400 billion dollar industry. + +So again, this is structure +property relations in action. + +So let me ask you another +question. + +It turns out that products that +are derived from nature-- + +a good example being sugar, +which is produced by sugar + +beets or sugar cane-- + +produces a molecule only +of one handedness. + +They are [? enantiomer ?] + +pure. + +But every synthetic compound +that can exist in right handed + +and left handed forms occurs +with equal probability. + +So how do you make a +pharmaceutical of one + +particular handedness? + +And this is an interesting +question because I think it + +was two years ago the Nobel +Prize in chemistry was given + +to three people for their work +in being able to synthesize + +molecules of a given +handedness. + +Anybody an idea how you do it? + +AUDIENCE: I don't have an idea +how you do it, but what do you + +mean by one handedness +versus--? + +PROFESSOR: OK, left handed +or right handed. + +So my left hand is exactly the +same as my right hand, but I + +cannot match them into +congruence with one another. + +And we don't know how to +describe this other than we + +used the term derived +from our physiology. + +We say left handed +and right handed. + +So when I was referring to a +molecule of one handedness-- + +and I'll bring in a Xerox copy +of a couple of examples. + +There are many examples of +fairly common molecules which + +can exist in one form in which +the hydroxyl group points out + +this way, then another form +where the hydroxyl groups + +points out this way. + +Sorry, you should have +asked that earlier. + +AUDIENCE: So if it's not the +same molecule, it would be + +that molecule but--? + +PROFESSOR: Chemically, it is +exactly the same concept. + +But the way in which those +component models are + +configured has the same number +of side groups, the same + +number of appendages. + +But they, don't have +a better word. + +One is left handed. + +One is right handed. + +I'll give you some examples +next time. + +Somebody else, you +had a question? + +AUDIENCE: I was just going to +see if I could venture a guess + +how they do it. + +I was going to guess they use an +electric field that has its + +bearings to set the right handed +course [INAUDIBLE] that + +would make [? enantiomorphs ?] + +or more advantageous +than [INAUDIBLE]. + +PROFESSOR: That's +not a bad idea. + +Anything that could bias the +energy of one configuration + +over the other would do it. + +But actually, no reason why you +should know how to do it. + +If you knew how to do it, maybe +you could have gotten + +the Nobel Prize instead +of these other guys. + +But actually, you do it +through catalysis. + +And you use a catalyst which +itself has chirality. + +And that chirality favors the +formation of one molecule over + +the other almost exclusively. + +And that's why living +plants make-- + +or animals-- make chiral +molecules in just one + +handedness as well. + +So it's using a catalyst that +also has some chirality. + +AUDIENCE: How do you get the +one hundred catalysts + +[INAUDIBLE]? + +PROFESSOR: How do +you have it--? + +OK, there are lots +of materials. + +Any crystalline material that +does not have a mirror plane + +in it can exist in +chiral forms. + +And one of the classic examples +of this is quartz. + +Quartz is SiO2. + +And quartz has actually only +a threefold symmetry. + +But it forms crystals that look +prismatic, as though they + +were hexagonal prisms. + +And if I draw two of these +prisms side by side, you could + +not tell which prism +was left handed and + +which was right handed. + +But quartz ends up growing with +a couple of little facets + +on it that look like this. + +They spiral up this way in a +crystal of one handedness and + +they spiral up in the opposite +direction for a crystal of + +opposite handedness. + +So the external faces on the +crystal show you that this + +crystal shape cannot be mapped +one into another. + +They are of opposite +handedness. + +And they have very different +properties. + +And so here's an example. + +I'm not answer your question. + +I'm talking around it very +adroitly in the hope that if I + +talk enough you will forget +what you asked. + +But how do you make +a chiral catalyst? + +Well, there are some materials +if you prepare them in a + +single crystal form, once you +nucleate one enantiomorph, + +that will continue to grow. + +So I would presume one +could do exactly + +the same with a catalyst. + +Actually, the properties of +quartz are strikingly + +different for these two +different forms. + +If you would subject the crystal +to compression, this + +crystal would develop +a positive + +charge on the surface. + +This crystal would develop +a negative + +charge on the surface. + +That's a property that we'll +discuss in detail later on. + +That's something called +piezoelectricity, literally + +pressure electricity. + +So the nature of the charge +induced on the crystal is + +different for the crystals +of the two chiralities. + +OK, any other comment +or question? + +OK, last time we had taken the +first small steps in what will + +turn out to be a long and + +protracted process of synthesis. + +We've covered by now some of +the general notions of + +operations that can exist in +a pattern, two dimensional + +pattern of wallpaper or fabric +or a three dimensional pattern + +that constitutes a crystal. + +And we said that in three +dimensions, there are four + +basic different operations that +can exist that tell you + +how one part of the system +is related to another. + +There is an operation +of translation. + +And this has all the +characteristics of a vector, + +magnitude and direction. + +We summarize that translational +periodicity by a + +set of fiducial markers that +are called lattice points. + +And analytically, the +transformation takes the + +coordinate x, y, z. + +And if you do the operation +once, maps this to x plus a, y + +plus b, z plus c where the +translation has components a, + +b, and c in x, y, and +z directions. + +Another operation is the +operation of reflection. + +And what this operation does is +to take the coordinates of + +an initial part of the space +atom or location and maps it + +into some location where one +direction is reversed in sign. + +Which direction that is or +whether it's a pair of + +directions will depend on how +the reflection locus is + +located relative to the +coordinate system. + +Next, there was an operation +of rotation. + +And this involves repeating +things at angular intervals. + +Take the space or the location +of the atom and rotate it + +through some angle, alpha, +about some rotation, a. + +And in a sense, this is +a periodicity which is + +reminiscent of translation +except translation strings + +things out in a line. + +Rotation wraps up the +directions about + +some central axis. + +But it's also periodic. + +Then finally, in three +dimensions, there is another + +operation called inversion. + +And what this does is-- + +to could describe it as such +in literal terms-- + +take something and turns it +inside out to a point. + +So if the inversion point were +at the origin, it would take + +x, y, z, and map it into minus +x, minus y, minus z. + +And then, we concluded last time +with a definition of a + +vocabulary for indicating +analytically a single + +operation, the set of operations +that constitutes + +the symmetry element, and then +a geometric symbol for the + +locus of that operation. + +And for translation, we could +represent a single + +operation by t. + +The set of operations +could be-- + +and I'll use this customary +set of braces to + +indicate the set-- + +this would be a one dimensional +lattice, a set of + +operations, p, where p is +an integer times t. + +The geometric symbol, it's +convenient to use an arrow + +extending from one lattice +point to another. + +But I emphasize that there's +no unique origin to the + +translation. + +We cannot be entitled to say +it sits here as opposed to + +down here or down here. + +There are an infinite number +of parallel directions that + +could specify a given interval +between lattice points. + +For rotation operations, the +notation for a single + +operation in as much as we must +specify two things, the + +point about which we rotate and +then the angular interval + +about which we perform +the rotation. + +And so we need to specify two +things, the location of the + +axis, a point a, and +the angle, alpha, + +through which we rotate. + +The set of operations, the +rotation axis, is indicated by + +an integer, n, where the +rotation part of the operation + +is 2 pi divided by +the integer, n. + +So we would use, for example, 2 +to represent a rotation axis + +where things were moved through +180 degrees, 3 for a + +symmetry where things were +mapped through intervals of + +120 degrees, and 22 for my +good friend, the Saguaro + +cactus, which is left invariant +perhaps by a + +rotation through 1/22 of 2 pi. + +For the geometric symbol for a +rotation axis, we will use a + +little polyhedron. + +Triangle for a threefold axis. + +Square for a fourfold axis. + +For a twofold axis, the +polyhedron that had that + +symmetry would be +a line segment. + +So we'll take a little artistic +license and let the + +middle of the line segment +bulge out a little bit. + +Finally for inversion, for +reasons that will not become + +clear for another meeting or +two, the single operation is + +denoted one bar. + +The set of operations of which +there are only two, inverting + +and coming back again, +also indicated by + +the symbol one bar. + +And the geometric symbol for +the locus is a little, tiny + +circle that's open large enough +to be noticed, but not + +so large that it looks like an +atom in an atomic arrangement. + +So there's our basic +bag of tricks. + +And last time, we had already +used some simple geometry to + +come to a rather astonishing +conclusion. + +Yes, sir? + +AUDIENCE: Reflection? + +PROFESSOR: Reflection, that's +this middle one. + +Whoops, not going to help. + +Thank you very much. + +I get excited and +carried away. + +OK, reflection, the +second operation. + +Single operation, although +crystallographers don't often + +use it in condensed matter +physics, a single operation is + +represented by the +symbol sigma. + +Symbol for a mirror plane is +m, easily appreciated. + +And the geometric locus across +which things are reflected + +left to right and vice versa +is done with a bold, solid + +line when you're looking down +parallel to the surface of the + +reflection locus. + +Then, I will now be caught up. + +And I can set off on +something new. + +We had said that in a pattern, +very often more than one of + +these operations are combined +in a single space. + +And one of the things that +must be present-- + +if the symmetry of +the entity we are + +discussing is a crystal-- + +one of the things that must be +present is a translation. + +And so I asked last time the +question, what if we want to + +say that our space has a +translational periodicity + +described by t. + +And then, I add to one lattice +point a rotation operation, A + +alpha, that has to get +translated to another location + +where that operation, +A alpha, exists. + +And if A alpha exists and I +repeat that translation by a + +rotation alpha, I'm going to +have a sheath of translations + +all separated by a +distance alpha. + +If I single out the one that is +removed from the first by + +an operation of rotation A alpha +in a counterclockwise + +direction and single out from +that sheath another one that + +is alpha away in the clockwise +direction. + +Then, I have lattice points +at the end of all of these + +translations. + +But these two guys up here +are also lattice points. + +And therefore, I have mucked up +to the entire construction + +unless I can claim that this +distance between these two + +lattice points is either T or +some multiple P times T, where + +P is an integer. + +And then lickety split, before +you could catch your breath in + +wonder, I dropped a +perpendicular down to the + +original translation. + +This distance in here was PT. + +This distance on either +side was T times + +the cosine of alpha. + +And that led me to a constraint +that alpha, that + +rotation operation A alpha, if +it were to be combined with + +translation, would be restricted +to values such that + +the cosine of alpha was equal +to 1 minus an integer P + +divided by 2. + +Wow, simple, but so incredibly +profound. + +What came out of this +was that alpha could + +either be 0 or 360 degrees. + +That was a one-fold axis. + +Alpha could be 180 degrees. + +That was a two-fold axis. + +120, which would be the +angular rotation of a + +three-fold axis. + +90, that would be the operation +of a four-fold axis. + +Or 60, that would be the +operation of a six-fold axis. + +It's incredible. + +Anything, any pattern, any +crystal that is based on a + +lattice can contain only these +five rotational symmetries + +including no symmetry at all. + +So this says a lot about what +the morphology of crystalline + +materials are permitted to be. + +Then, we looked at the nature +of the lattices that were + +described by these angular +rotations. + +And we found that there were +only three types of lattices + +that were required +by rotation. + +These were two dimensional +lattice nets. + +One was a general oblique net +which had two different + +translations, some arbitrary +angle between them, two + +translations, T1 and T2, which +were not equal to one another. + +We would call this +the oblique net. + +Then, there was another net that +was square in the sense + +that two translations, +T1 and T2, were + +identical to one another-- + +not close, but identical. + +And the angle between them was +identically 90 degrees. + +This oblique net could accept +either a one-fold axis or a + +two-fold axis. + +This was the specialized shape +that was required by a + +four-fold axis. + +And then finally, there was +another net that looked + +oblique except it was a +specialized oblique net. + +It had two translations, T1 and +T2, which were identical + +just as in the square net and +an angle between them, which + +was exactly 120 degrees. + +And this same sort of net +could be compatible with + +either a three-fold axis +or a six-fold axis. + +Then, we took the only other +operation that could be + +present in a two dimensional +pattern, and this was the + +operation of reflection, +a mirror point, m. + +And we saw that this by itself +could require two different + +sorts of specializations in a +lattice, a lattice in which + +two directions were exactly +orthogonal but the lengths of + +the translations were unequal. + +And then, a diamond +shaped net-- + +and this was a new wrinkle. + +This was a net that had two +translations that were + +Identical in length and an +arbitrary angle between them. + +Or alternatively, if we chose +to pick a redundant lattice, + +one that had two translations, +T1 and T2 prime which were + +different but an angle between +them that was exactly 90 + +degrees, so this one we would +refer to as a rectangular + +lattice, a rectangular net, +and this one as a centered + +rectangular net-- + +same shape, but an extra lattice +point in the middle. + +Why pick a double cell, which +is redundant, takes up more, + +and doesn't convey any +more information? + +And the advantage comes when +you want to analytically + +describe the relation between +different directions or the + +positions of atoms +within the cell. + +In that case, an orthogonal +coordinate system, even if + +it's not Cartesian, is of +immense advantage as opposed + +to an oblique system. + +OK, slightly out of breath, but +that is everything we've + +covered to this point. + +And you can find this material +discussed in the first + +chapter, in the introduction, +and then half of the second + +chapter of Berger's book if +you want to read over it. + +OK, any questions or comments? + +All right, I wanted to say a +little bit more about lattices + +and something with which you +are no doubt familiar, but + +perhaps have some questions +about why one does it in such + +an obscure, difficult way. + +And let me introduce what's done +by an analogy which we + +have around us in +everyday life. + +Let me draw a system of streets +and avenues for a city + +that might be one like Boston +where the streets were laid + +out by cows wandering around +in search of forage. + +And suppose somebody met you on +the street and said, may I + +stop you here at point A +and ask you a question? + +How do I get from point +A to point B? + +That's not a vector. + +That's a point. + +How do I do that? + +You would not say, go 342 meters +to the east and 26.4 + +meters to the south. + +That's perfectly logical that is +admirably Cartesian but you + +wouldn't do it that way what we +just said you would say go + +one block straight ahead, and +then turn one block to your + +left, and then go down the +street to your right and turn + +to your right again, and +you'll be right there. + +You can't miss it. + +Of course, the person in Boston +would miss it and would + +have to stop a second time and +ask again and by a method of + +successive approximations +eventually get to where he or + +she would like to be. + +I submit if a system gives you +a grid, it makes sense to use + +that grid as the basis vectors +of coordinate system even if + +the intervals are different, in +two different directions, + +and even though the intervals +might be not vectors that are + +orthogonal to one another. + +If the system is periodic and +has this grid work to it, it + +makes sense to use that as the +basis of a coordinate system. + +So if we have a lattice that +is oblique and there are + +lattice points defined by these +two translations, T1 and + +T2, it makes great sense if you +want to specify the vector + +that runs from this lattice +point to this lattice point to + +do that by saying that this is a +lattice point that is at the + +end of the vector +1 T1 plus 2 T2. + +And that, just as a system of +streets and avenues, is a lot + +more efficient than saying go +12.2 angstroms in the x + +direction and go 15.3 angstroms +in the y direction. + +What we have defined here is +something that is called a + +rational direction. + +And a rational direction is +something that is going to be + +a direction that extends +between lattice points. + +And what's rational about it +is that the coefficients in + +front of T1 and T2 that would +appear would be integers. + +And an integers is sometimes +referred to + +as a rational number. + +That would be quite different +from a vector that extended + +from a lattice point to, let's +say, some atom that is within + +the boundaries of this cell. + +And this might be a radial +vector from the + +origin to one lattice. + +And that could be used +to specify the atomic + +coordinates. + +This is going to complete the +dichotomy, a feature that is + +referred to as irrational. + +Why? + +Because the components of the +steps along T1, x, and along + +T2, y, are going to be +fractional numbers. + +So you'll hit irrational +notation for directions that + +go to different locations +with a unit cell. + +You'll use rational vectors in +directions that extend between + +integral numbers of +lattice points. + +These directions occur all the +time when one discusses the + +physical properties +of crystals. + +I'm sure in any class that +you've had that's discussed + +mechanical properties, one of +the favorite topics is to + +discuss the ways in which close + +packed metals can deform. + +And this can be discussed easily +in terms of one layer + +of close packed spheres +sliding over another. + +And one of the ways that the +layer can slide to go from one + +set of close packed hollows +to another is in a + +direction like this. + +And that turns out to be +a rational direction. + +And these are directions in +which a close packed metal + +will easily deform. + +So directions of easy plastic +deformations almost always + +involve rational directions. + +So there is a unique application +of these sorts of + +features in the discussion +of mechanical properties. + +Another thing that can happen +is that a particular + +structure, if it is weakly +bonded or relatively weakly + +bonded in one direction, if you +come down with a chisel on + +that plane and give it a little +tunk with a hammer, the + +crystal will fall exactly in +half and give you two very + +smooth surfaces on either +side of some plane. + +And the reason is if you look +down into the guts of the + +crystal and look at the atoms +and how they're bonded + +together, there may be some +direction of weak bonding + +between atoms that is very +easily separated by some sort + +of mechanical force. + +This is true even for crystals +that are very strongly bonded. + +The way in which people begin +to facet diamonds, for + +example, is to sit for a month +and study the diamond and then + +decide how you're going to put a +straight edge to it and give + +it a little tunk so that it +falls neatly into two pieces + +at the sides that you +want to facet. + +Doesn't always work, so you sit +for a long time to figure + +out just what you're +going to do. + +I think diamond cutters burn +out early and have a useful + +career that last perhaps +3 and 1/2 years. + +And then, they're burned out. + +I don't know that for sure. + +But it must be a nerve +wracking way + +of making an existence. + +Not a far-fetched story. + +At one time, I was doing a +diffraction study on a + +material which was a low +temperature face, very + +interesting, but formed stable +only at such low temperatures + +that you could not make it by +cooking the components. + +But it had been found as a +mineral in the Swiss Alps, all + +sorts of exotica attached to +this particular material. + +There was a particular place +up in the Alps which had a + +very unusual chemistry involving +lead and arsenic and + +thallium and sulfur-- + +not what you find in your usual +backyard rock pile. + +And there was something like 37 +unique minerals that were + +found in this little spot that +were known nowhere else on the + +face of the Earth. + +And I was very interested +in the atomic + +arrangements in one of them. + +So I wrote to the British Museum +that had found the sole + +supplier of this +material that-- + +back in about 1901 or so-- + +I wrote and I said, +do you have any + +crystals of this stuff? + +Yes. + +Would you like to study it? + +And I said yes, I would. + +Well, we'd be happy +to send it. + +But please be careful not to +damage the morphology because + +it is a very rare material. + +So I said fine. + +I'm as careful as the +next meticulous guy. + +They sent two crystals. + +The crystals measured-- + +one of them was 2/10 of a +millimeter in diameter. + +One of them was about 0.15 +millimeters in diameter. + +And I was supposed to take off +a piece for study without + +damaging the morphology. + +Man, I felt just like one of +these Dutch diamond cutters. + +I sat and I looked at those two +little suckers under the + +microscope for, I +think, a week. + +And then finally, the moment of +truth, and I took a needle + +and popped off a corner. + +And it went into two pieces. + +One went for a microprobe +analysis to determine the + +composition. + +One of them went to a single +crystal x-ray diffraction + +study to determine the +atomic arrangement. + +Both analyses can be done on a +very small piece of material. + +So my story about the diamond +cutter agonizing before + +looking for a cleavage or a +fracture surface is not just + +made up fiction. + +It is something that, when you +work with crystals very often, + +is encountered. + +OK, cleavage planes are also +rational directions. + +The cleavage plane of rock +salt is legendary. + +And it's nice, really, to spend +an afternoon splitting + +it up just to see how +neat it falls apart. + +OK, how are we going to denote +rational planes? + +Talked about rational and +irrational directions, and + +that's easy. + +How are we going to describe +rational planes in crystals? + +And this is rather bizarre. + +So let me tell you what you do, +which is something you've + +probably heard before, and +then explain why one + +does it this way. + +Let's suppose we have three +vectors that are the vectors + +we will use to define +the lattice. + +And if there is a plane hanging +on one of these + +lattice points, everything is +translationally periodic, so + +there must be a similar plane +in the same orientation that + +passes through all the +lattice points. + +So let me look at a very special +plane, namely one that + +cuts a lattice point at +an integral number of + +translations, T3, and an +integral number of + +translations, T2, and an +integral number of + +translations, T1. + +And I don't want any common +factor here, so let's look at + +this point here. + +And now, let's connect these +lattice points together. + +And that will define +a plane uniquely. + +And what is special about this +point is that it hits a + +lattice point on each +of these three axes. + +And this is a plane that I'll +call the intercept plane. + +There will be a similar plane +hanging on all of these other + +lattice points. + +But those planes will not hit +a lattice point on the + +directions of T1, T2, and T3. + +This is the first one out from +the origin that does that. + +Now, we will use this oblique +set of vectors, T1, T2, and + +T3, as the coordinate system +for specifying + +direction and angles. + +So let me ask a question now +that's going to blow you away. + +What is the equation for the +locus of this plane If I use + +this oblique coordinate system +based on T1, T2, and T3 as my + +coordinate system? + +Holy mackerel. + +What a way to wrap +up a Tuesday. + +Actually, it's very, +very easy. + +First of all, it has to +be a linear equation. + +So it's going to be linear +in x, y, and z. + +So something times x, something +times y, something + +times z equals a constant. + +That's going to define, if I use +the proper coefficients, + +the equation for this plane. + +And let me determine quite +easily what those + +coefficients are. + +What is the coordinate of this +point, which sits on the plane + +and therefore must satisfy +this equation? + +Well, y is 0. z is zero. + +So this is the point-- + +if I am a translations out from +the origin, this is the + +point x equals A. + +So if I'm three translations +out from the origin, that + +integer is the coefficient in +front of x because when y and + +z are 0, if I make the constants +on the right hand + +side equal to 1, this is +the point x equals a. + +And it's nice to have one +on the right hand side. + +That's about as nice and neat +and tidy a constant as you + +could have. + +We do the same thing for this +point at the end of two + +translations, T2. + +let's say in general that for +this intercept plane, we are + +two translations out along T2. + +So for the point 0-- + +this point, 0-- + +if I put the number of +translations, b, in front of + +y, This is the point y equals +b when x and z are 0. + +And in the same way, if we are C +translations out along T3, C + +times z-- that integer-- +is equal to 1. + +AUDIENCE: Can you explain +it again? + +[INAUDIBLE] + +PROFESSOR: I'm sorry. + +What? + +AUDIENCE: [INAUDIBLE]. + +PROFESSOR: Yeah, I'm saying I'm +going to [INAUDIBLE] my + +definition at a plane which +cuts the direction of T1, + +which is what I called +the variable x, at a + +translations out. + +In this case, this is 3. + +This is 2. + +And this is 1. + +So for this particular example, +I would have 3x plus + +2y plus 1z equals 1 because when +y is 0 and z is 0, the + +point on the surface is-- + +1/3. + +Sorry. + +Good question. + +OK, that's a lot better. + +I would've gotten in much deeper +trouble if you had let + +me persist in that. + +So thank you for +the correction. + +But now, I would like to have +integers out in front here. + +So let me multiply both sides +through by A times B times C. + +And now, I do get something with +integers in front of x + +and integers in front of y. + +And this would be A times C, +and integers in front of z. + +And that's A times B equals-- + +and now on the right side, I +would have a times B times C. + +So everything, every coefficient +and the term on + +the right hand side are +products of integers. + +So they are all integers +themselves. + +OK, let me next ask the question +these planes passing + +through all of the other +lattice points that are + +contained within this little +tetrahedron of volume are + +going to be equally spaced. + +How will I claim that these +planes are all equally spaced? + +Well, that's easy just +in general terms. + +Here is a lattice point. + +There's a plane passing +through it. + +There's some lattice point +neighboring it that's out at + +distance, D. Here is another +lattice point. + +It has a plane passing +through it. + +There must be a plane out here +on D. And I'm not going to be + +able to have the same +environment for every lattice + +point unless all of these planes +have the same spacing + +from one another. + +So to say that they pass in +lattice points in the + +environment of everybody lattice +point is by definition + +identical is possible only if +the planes are equally spaced. + +Next question-- + +and I'm not going to be gutsy +enough to try to demonstrate + +this in three dimensions, +so let me do it in two. + +Let us ask the question, how +many planes are there hanging + +on all the lattice points +between the origin and the + +intercept plane? + +And let me demonstrate that for +a two dimensional case. + +And I will refer you to a +drawing in Berger's book + +because this is not convincing +unless you do + +it absolutely exactly. + +And to do that in front of a +live audience with chalk is + +not always the easiest +thing in the world. + +So here is T1. + +Here is T2. + +And let me look at this plane. + +This is the intercept plane. + +A is equal to 3 and +B is equal to 2. + +Now, what I'm going to do is +to use plus and minus the + +translation T1 to repeat +this intercept plane. + +OK, I go minus T1. + +And that's going to give +me a plane in here. + +I'm going to go minus +T1 again. + +And that's going to give +me a plane in here. + +So I have split the interval +between the origin and the + +intercept plane into A parts. + +OK so far? + +Let me now use the +translation T2. + +And I will use the plus and +minus the translation T2 to + +take this stack of A planes +and repeat it B times. + +And that's going to take the +plane at the origin and move + +it up to here. + +It's going to move the planes +into stacks like this. + +I will map the stack of +A planes B times. + +And that is going to give me A +times B intervals except if a + +special condition applies. + +And then, I will go back +to it in a moment. + +This is the equation of +the intercept plane. + +I will argue that the three +dimensional analogy of what + +I've done is that there will be, +if I let the translations + +T1, T2, and T3 go to work, there +will be A times B times + +C intervals between the origin +and the intercept plane. + +So if this is the intercept +plane and this is A times B + +times C times the spacing +between the planes out from + +the origin, then the first plane +from the origin is going + +to happen to intercept which +is 1ABC to the first. + +And ABC divided by ABC turns out +to be 1 for any value of + +A, B, and C. + +So the first plane from the +origin is going to have the + +simple equation be BC times x +plus AC times y plus AB times + +z equals 1. + +And the second plane out from +the origin will have the same + +coefficients except the term +on the left will be 2. + +Third plane will have 3 on the +right and finally the integer + +ABC when we get to the +intercept plane. + +OK, now I'm ready to make a +momentous definition just as + +we get five of the hour. + +B times C is an integer. + +Let me define that integer +by a single integer. + +And just for the heck of it, +I'll call it H. A times C is + +an integer. + +Let me call that integer K. +And AB is an integer. + +Let me call that integer L. + +So using T1 and T2 and T3 as +the basis vectors of my + +coordinate system, the first +plane from the origin has the + +equation Hx plus Ky +plus Lz equals 1. + +And these three integers, H, K, +and L, are said to be the + +Miller indices of this plane. + +PROFESSOR: Yes, sir? + +AUDIENCE: Just on that figure, +[INAUDIBLE] connect to the + +lattice points. + +I'm trying to make sense of why +did you put the planes in + +between them? + +PROFESSOR: OK, what I did was +I started with just these + +three hanging on the lattice +point separated by T1. + +And then, I move this by T2. + +OK, so T2 has a plane +in the middle of it. + +And it's going to move +that up to here and + +give me another plane. + +If you just draw this out-- +and you're going to get a + +problem that asks +you to do this-- + +since these integers are +mutually prime, the second + +translation is going to +interleave planes + +between the first set. + +And it gets even worse in three +dimensions because the + +third translation, which is the +axis C translations out, + +is going to interleave that +set of AB planes C times. + +And they have to be at +equal distances. + +Otherwise, the definition of +the lattice point having + +identical environment +is violated. + +OK, these are the infamous +Miller indices that are the + +downfall of all freshman +who take 309.1. + +It is not necessarily a very +straightforward definition. + +But the advantage of it is that +it lets you analytically + +describe the locus of the +lattice planes in a very, very + +convenient way. + +Actually, let me tell you +something maybe you have not + +heard before. + +These indices were not invented +by a fellow named + +Miller who was an Englishman +who wrote a book, an early + +book on crystallography that +incorporated this notation. + +The guy who invented them and +first proposed them was + +Auguste Bravais, a very famous +French crystallographer-- + +mathematician, actually-- + +who gave his name to the three +dimensional space lattices. + +These are universally +known as the Bravais + +lattices, 14 of them. + +It's a great name. + +It's music. it rolls +of the tongue-- + +Bravis, Bravais. + +Actually, Bravias wasn't +the first guy to + +try to derive them. + +The first guy who tried to +drive the lattices was + +somebody named Frankenheim. + +He blew it. + +He didn't get 14. + +He only found 13. + +So there's a moral here. + +If immortality is your game, +get it right the first time + +because everybody has heard +of Bravais, Bravais. + +Nobody has heard +of Frankenheim. + +And for that, I say thank god. + +What a name! + +It makes you think of somebody +who's got plugs in his neck + +and walks around like this +and has a green face. + +Frankenheim-- + +bah! + +Bravais, Bravais, it really +sings to you. + +OK, I'm getting silly so it's +time to quit and take a break. + +Come up and say hello +to Rodney. \ No newline at end of file diff --git a/AyCLokHV774.txt b/AyCLokHV774.txt new file mode 100644 index 0000000000000000000000000000000000000000..bbeef60fde867de2af2fe790aea3c0ec93d2bdca --- /dev/null +++ b/AyCLokHV774.txt @@ -0,0 +1,1203 @@ +align:start position:0% + +we often think of a Bernoulli process as + + align:start position:0% +we often think of a Bernoulli process as + + + align:start position:0% +we often think of a Bernoulli process as +a stream of arriving traffic what + + align:start position:0% +a stream of arriving traffic what + + + align:start position:0% +a stream of arriving traffic what +happens if we merge two streams for + + align:start position:0% +happens if we merge two streams for + + + align:start position:0% +happens if we merge two streams for +example consider a server that receives + + align:start position:0% +example consider a server that receives + + + align:start position:0% +example consider a server that receives +traffic from two independent sources how + + align:start position:0% +traffic from two independent sources how + + + align:start position:0% +traffic from two independent sources how +do we describe the total traffic that + + align:start position:0% +do we describe the total traffic that + + + align:start position:0% +do we describe the total traffic that +arrives to this server here's a precise + + align:start position:0% +arrives to this server here's a precise + + + align:start position:0% +arrives to this server here's a precise +model we have two streams that + + align:start position:0% +model we have two streams that + + + align:start position:0% +model we have two streams that +correspond to Bernoulli processes with + + align:start position:0% +correspond to Bernoulli processes with + + + align:start position:0% +correspond to Bernoulli processes with +some parameters each P and Q + + align:start position:0% +some parameters each P and Q + + + align:start position:0% +some parameters each P and Q +respectively + + align:start position:0% +respectively + + + align:start position:0% +respectively +and each one of these processes receives + + align:start position:0% +and each one of these processes receives + + + align:start position:0% +and each one of these processes receives +arrivals at certain times that we + + align:start position:0% +arrivals at certain times that we + + + align:start position:0% +arrivals at certain times that we +indicate by crosses and similarly for + + align:start position:0% +indicate by crosses and similarly for + + + align:start position:0% +indicate by crosses and similarly for +the second process we assume that these + + align:start position:0% +the second process we assume that these + + + align:start position:0% +the second process we assume that these +two processes are independent and what + + align:start position:0% +two processes are independent and what + + + align:start position:0% +two processes are independent and what +we mean by this is that any collection + + align:start position:0% +we mean by this is that any collection + + + align:start position:0% +we mean by this is that any collection +of random variables associated with the + + align:start position:0% +of random variables associated with the + + + align:start position:0% +of random variables associated with the +first process will be independent from + + align:start position:0% +first process will be independent from + + + align:start position:0% +first process will be independent from +any collection of random variables + + align:start position:0% +any collection of random variables + + + align:start position:0% +any collection of random variables +associated with the second process we + + align:start position:0% +associated with the second process we + + + align:start position:0% +associated with the second process we +now merge the two processes as follows + + align:start position:0% +now merge the two processes as follows + + + align:start position:0% +now merge the two processes as follows +whenever there is an arrival in any of + + align:start position:0% +whenever there is an arrival in any of + + + align:start position:0% +whenever there is an arrival in any of +the original processes we record an + + align:start position:0% +the original processes we record an + + + align:start position:0% +the original processes we record an +arrival in the merged process as in this + + align:start position:0% +arrival in the merged process as in this + + + align:start position:0% +arrival in the merged process as in this +picture notice that we do not make a + + align:start position:0% +picture notice that we do not make a + + + align:start position:0% +picture notice that we do not make a +distinction between those slots at which + + align:start position:0% +distinction between those slots at which + + + align:start position:0% +distinction between those slots at which +there was an arrival in only one of the + + align:start position:0% +there was an arrival in only one of the + + + align:start position:0% +there was an arrival in only one of the +original process versus those slots in + + align:start position:0% +original process versus those slots in + + + align:start position:0% +original process versus those slots in +which there was an arrival in both of + + align:start position:0% +which there was an arrival in both of + + + align:start position:0% +which there was an arrival in both of +the original processes in both cases we + + align:start position:0% +the original processes in both cases we + + + align:start position:0% +the original processes in both cases we +just say that there was an arrival in + + align:start position:0% +just say that there was an arrival in + + + align:start position:0% +just say that there was an arrival in +the merged process and so collisions + + align:start position:0% +the merged process and so collisions + + + align:start position:0% +the merged process and so collisions +arrivals in both of the original + + align:start position:0% +arrivals in both of the original + + + align:start position:0% +arrivals in both of the original +processes are counted as only one + + align:start position:0% +processes are counted as only one + + + align:start position:0% +processes are counted as only one +arrival in the merged process now what + + align:start position:0% +arrival in the merged process now what + + + align:start position:0% +arrival in the merged process now what +can we say about the merged process we + + align:start position:0% +can we say about the merged process we + + + align:start position:0% +can we say about the merged process we +will argue that it is a Bernoulli + + align:start position:0% +will argue that it is a Bernoulli + + + align:start position:0% +will argue that it is a Bernoulli +process with a certain parameter that we + + align:start position:0% +process with a certain parameter that we + + + align:start position:0% +process with a certain parameter that we +will compute to check the Bernoulli + + align:start position:0% +will compute to check the Bernoulli + + + align:start position:0% +will compute to check the Bernoulli +property for the merged process the + + align:start position:0% +property for the merged process the + + + align:start position:0% +property for the merged process the +first thing we need to ensure is the + + align:start position:0% +first thing we need to ensure is the + + + align:start position:0% +first thing we need to ensure is the +independence assumption independence + + align:start position:0% +independence assumption independence + + + align:start position:0% +independence assumption independence +across slots let us look at two typical + + align:start position:0% +across slots let us look at two typical + + + align:start position:0% +across slots let us look at two typical +slots and to do this it helps to define + + align:start position:0% +slots and to do this it helps to define + + + align:start position:0% +slots and to do this it helps to define +some notation that XT and YT + + align:start position:0% +some notation that XT and YT + + + align:start position:0% +some notation that XT and YT +the original processes and let ZT be the + + align:start position:0% +the original processes and let ZT be the + + + align:start position:0% +the original processes and let ZT be the +merged process the random variable Z T + + align:start position:0% +merged process the random variable Z T + + + align:start position:0% +merged process the random variable Z T +is determined in some way by the random + + align:start position:0% +is determined in some way by the random + + + align:start position:0% +is determined in some way by the random +variables XT and YT if I told you if + + align:start position:0% +variables XT and YT if I told you if + + + align:start position:0% +variables XT and YT if I told you if +there was an arrival in the first and + + align:start position:0% +there was an arrival in the first and + + + align:start position:0% +there was an arrival in the first and +the second process you can tell whether + + align:start position:0% +the second process you can tell whether + + + align:start position:0% +the second process you can tell whether +there was an arrival in the merged + + align:start position:0% +there was an arrival in the merged + + + align:start position:0% +there was an arrival in the merged +process and similarly the random + + align:start position:0% +process and similarly the random + + + align:start position:0% +process and similarly the random +variable Z T plus one is determined in + + align:start position:0% +variable Z T plus one is determined in + + + align:start position:0% +variable Z T plus one is determined in +some way from XT plus one and YT plus + + align:start position:0% +some way from XT plus one and YT plus + + + align:start position:0% +some way from XT plus one and YT plus +one what this is saying is that whether + + align:start position:0% +one what this is saying is that whether + + + align:start position:0% +one what this is saying is that whether +we have an arrival at this slot is + + align:start position:0% +we have an arrival at this slot is + + + align:start position:0% +we have an arrival at this slot is +determined by what happens in these two + + align:start position:0% +determined by what happens in these two + + + align:start position:0% +determined by what happens in these two +slots and whether we have an arrival in + + align:start position:0% +slots and whether we have an arrival in + + + align:start position:0% +slots and whether we have an arrival in +this slot is determined by whatever + + align:start position:0% +this slot is determined by whatever + + + align:start position:0% +this slot is determined by whatever +happens in these two slots now we have + + align:start position:0% +happens in these two slots now we have + + + align:start position:0% +happens in these two slots now we have +assumed that the two processes are + + align:start position:0% +assumed that the two processes are + + + align:start position:0% +assumed that the two processes are +independent so these two random + + align:start position:0% +independent so these two random + + + align:start position:0% +independent so these two random +variables are independent from those two + + align:start position:0% +variables are independent from those two + + + align:start position:0% +variables are independent from those two +random variables and furthermore across + + align:start position:0% +random variables and furthermore across + + + align:start position:0% +random variables and furthermore across +time this random variable will be + + align:start position:0% +time this random variable will be + + + align:start position:0% +time this random variable will be +independent from that random variable + + align:start position:0% +independent from that random variable + + + align:start position:0% +independent from that random variable +and this random variable will be + + align:start position:0% +and this random variable will be + + + align:start position:0% +and this random variable will be +independent from that random variable so + + align:start position:0% +independent from that random variable so + + + align:start position:0% +independent from that random variable so +these four random variables are + + align:start position:0% +these four random variables are + + + align:start position:0% +these four random variables are +independent of each other because of + + align:start position:0% +independent of each other because of + + + align:start position:0% +independent of each other because of +this we have ZT a function of two random + + align:start position:0% +this we have ZT a function of two random + + + align:start position:0% +this we have ZT a function of two random +variables that are independent from the + + align:start position:0% +variables that are independent from the + + + align:start position:0% +variables that are independent from the +two random variables that determine ZT + + align:start position:0% +two random variables that determine ZT + + + align:start position:0% +two random variables that determine ZT +plus one and for this reason ZT and ZT + + align:start position:0% +plus one and for this reason ZT and ZT + + + align:start position:0% +plus one and for this reason ZT and ZT +plus one will be independent + + align:start position:0% +plus one will be independent + + + align:start position:0% +plus one will be independent +this proves a pairwise independence + + align:start position:0% +this proves a pairwise independence + + + align:start position:0% +this proves a pairwise independence +property for the merged process but we + + align:start position:0% +property for the merged process but we + + + align:start position:0% +property for the merged process but we +can extend this argument to argue that + + align:start position:0% +can extend this argument to argue that + + + align:start position:0% +can extend this argument to argue that +the collection of random variables Z 1 + + align:start position:0% +the collection of random variables Z 1 + + + align:start position:0% +the collection of random variables Z 1 +up to ZT is a collection of independent + + align:start position:0% +up to ZT is a collection of independent + + + align:start position:0% +up to ZT is a collection of independent +random variables so we have the + + align:start position:0% +random variables so we have the + + + align:start position:0% +random variables so we have the +independence property now let us + + align:start position:0% +independence property now let us + + + align:start position:0% +independence property now let us +calculate the probability of an arrival + + align:start position:0% +calculate the probability of an arrival + + + align:start position:0% +calculate the probability of an arrival +during a typical slot during a typical + + align:start position:0% +during a typical slot during a typical + + + align:start position:0% +during a typical slot during a typical +time slot there are four possibilities + + align:start position:0% +time slot there are four possibilities + + + align:start position:0% +time slot there are four possibilities +for what may occur and these + + align:start position:0% +for what may occur and these + + + align:start position:0% +for what may occur and these +possibilities have to do with whether in + + align:start position:0% +possibilities have to do with whether in + + + align:start position:0% +possibilities have to do with whether in +the X process we have an arrival or not + + align:start position:0% +the X process we have an arrival or not + + + align:start position:0% +the X process we have an arrival or not +and in the + + align:start position:0% +and in the + + + align:start position:0% +and in the +I process whether we have an arrival or + + align:start position:0% +I process whether we have an arrival or + + + align:start position:0% +I process whether we have an arrival or +not the probability that we have an + + align:start position:0% +not the probability that we have an + + + align:start position:0% +not the probability that we have an +arrival in both processes because of + + align:start position:0% +arrival in both processes because of + + + align:start position:0% +arrival in both processes because of +Independence is the product of the + + align:start position:0% +Independence is the product of the + + + align:start position:0% +Independence is the product of the +probability that we have an arrival in + + align:start position:0% +probability that we have an arrival in + + + align:start position:0% +probability that we have an arrival in +the first process with the probability + + align:start position:0% +the first process with the probability + + + align:start position:0% +the first process with the probability +that we have an arrival in the second + + align:start position:0% +that we have an arrival in the second + + + align:start position:0% +that we have an arrival in the second +process similarly there is a probability + + align:start position:0% +process similarly there is a probability + + + align:start position:0% +process similarly there is a probability +P of an arrival in the first process and + + align:start position:0% +P of an arrival in the first process and + + + align:start position:0% +P of an arrival in the first process and +no arrival in the second there is a + + align:start position:0% +no arrival in the second there is a + + + align:start position:0% +no arrival in the second there is a +probability 1 minus P of no arrival in + + align:start position:0% +probability 1 minus P of no arrival in + + + align:start position:0% +probability 1 minus P of no arrival in +the first process and an arrival in the + + align:start position:0% +the first process and an arrival in the + + + align:start position:0% +the first process and an arrival in the +second process and finally there is + + align:start position:0% +second process and finally there is + + + align:start position:0% +second process and finally there is +probability 1 minus P times one minus Q + + align:start position:0% +probability 1 minus P times one minus Q + + + align:start position:0% +probability 1 minus P times one minus Q +of no arrival in either of the two + + align:start position:0% +of no arrival in either of the two + + + align:start position:0% +of no arrival in either of the two +processes the probability that we have + + align:start position:0% +processes the probability that we have + + + align:start position:0% +processes the probability that we have +an arrival in the merged process is the + + align:start position:0% +an arrival in the merged process is the + + + align:start position:0% +an arrival in the merged process is the +probability of this green event these + + align:start position:0% +probability of this green event these + + + align:start position:0% +probability of this green event these +are the cases in which an arrival gets + + align:start position:0% +are the cases in which an arrival gets + + + align:start position:0% +are the cases in which an arrival gets +recorded in the merged process so the + + align:start position:0% +recorded in the merged process so the + + + align:start position:0% +recorded in the merged process so the +probability of an arrival in the merged + + align:start position:0% +probability of an arrival in the merged + + + align:start position:0% +probability of an arrival in the merged +process is the sum of those three + + align:start position:0% +process is the sum of those three + + + align:start position:0% +process is the sum of those three +probabilities or another way to + + align:start position:0% +probabilities or another way to + + + align:start position:0% +probabilities or another way to +calculate it is 1 minus this probability + + align:start position:0% +calculate it is 1 minus this probability + + + align:start position:0% +calculate it is 1 minus this probability +here namely 1 minus 1 minus P times 1 + + align:start position:0% +here namely 1 minus 1 minus P times 1 + + + align:start position:0% +here namely 1 minus 1 minus P times 1 +minus Q and after you expand this + + align:start position:0% +minus Q and after you expand this + + + align:start position:0% +minus Q and after you expand this +product and do some cancellations you + + align:start position:0% +product and do some cancellations you + + + align:start position:0% +product and do some cancellations you +end up with this expression which is the + + align:start position:0% +end up with this expression which is the + + + align:start position:0% +end up with this expression which is the +probability of an arrival during a slot + + align:start position:0% +probability of an arrival during a slot + + + align:start position:0% +probability of an arrival during a slot +in the merged process of course this + + align:start position:0% +in the merged process of course this + + + align:start position:0% +in the merged process of course this +probability is constant across time and + + align:start position:0% +probability is constant across time and + + + align:start position:0% +probability is constant across time and +this together with the independence + + align:start position:0% +this together with the independence + + + align:start position:0% +this together with the independence +property establishes that the merged + + align:start position:0% +property establishes that the merged + + + align:start position:0% +property establishes that the merged +process is actually a Bernoulli process + + align:start position:0% +process is actually a Bernoulli process + + + align:start position:0% +process is actually a Bernoulli process +now let us end by answering one more + + align:start position:0% +now let us end by answering one more + + + align:start position:0% +now let us end by answering one more +question if I told you that at a certain + + align:start position:0% +question if I told you that at a certain + + + align:start position:0% +question if I told you that at a certain +time slot there was at least one arrival + + align:start position:0% +time slot there was at least one arrival + + + align:start position:0% +time slot there was at least one arrival +in the two processes which means that + + align:start position:0% +in the two processes which means that + + + align:start position:0% +in the two processes which means that +there was an arrival in the merged + + align:start position:0% +there was an arrival in the merged + + + align:start position:0% +there was an arrival in the merged +process what is the probability that + + align:start position:0% +process what is the probability that + + + align:start position:0% +process what is the probability that +there was an arrival in the first + + align:start position:0% +there was an arrival in the first + + + align:start position:0% +there was an arrival in the first +process now the event that there was an + + align:start position:0% +process now the event that there was an + + + align:start position:0% +process now the event that there was an +arrival in the first process is this + + align:start position:0% +arrival in the first process is this + + + align:start position:0% +arrival in the first process is this +event here so we're trying to calculate + + align:start position:0% +event here so we're trying to calculate + + + align:start position:0% +event here so we're trying to calculate +the conditional probability of the blue + + align:start position:0% +the conditional probability of the blue + + + align:start position:0% +the conditional probability of the blue +event given that the green event has + + align:start position:0% +event given that the green event has + + + align:start position:0% +event given that the green event has +occurred we use the definition of + + align:start position:0% +occurred we use the definition of + + + align:start position:0% +occurred we use the definition of +conditional probabilities the + + align:start position:0% +conditional probabilities the + + + align:start position:0% +conditional probabilities the +conditional probability is + + align:start position:0% +conditional probability is + + + align:start position:0% +conditional probability is +equal to the probability that both + + align:start position:0% +equal to the probability that both + + + align:start position:0% +equal to the probability that both +events happen which in this case is the + + align:start position:0% +events happen which in this case is the + + + align:start position:0% +events happen which in this case is the +intersection of the blue and the green + + align:start position:0% +intersection of the blue and the green + + + align:start position:0% +intersection of the blue and the green +event which coincides with the blue + + align:start position:0% +event which coincides with the blue + + + align:start position:0% +event which coincides with the blue +event and the probability of the blue + + align:start position:0% +event and the probability of the blue + + + align:start position:0% +event and the probability of the blue +event is the sum of these two numbers is + + align:start position:0% +event is the sum of these two numbers is + + + align:start position:0% +event is the sum of these two numbers is +equal to P and then we divide by the + + align:start position:0% +equal to P and then we divide by the + + + align:start position:0% +equal to P and then we divide by the +probability of the conditioning event + + align:start position:0% +probability of the conditioning event + + + align:start position:0% +probability of the conditioning event +this is the probability of an arrival + + align:start position:0% +this is the probability of an arrival + + + align:start position:0% +this is the probability of an arrival +but this is what we have just calculated + + align:start position:0% +but this is what we have just calculated + + + align:start position:0% +but this is what we have just calculated +which is P plus Q minus P times Q \ No newline at end of file diff --git a/B7F6vh_plHw.txt b/B7F6vh_plHw.txt new file mode 100644 index 0000000000000000000000000000000000000000..08f7ab58a63504f11b02df5be81c064bf5c64a00 --- /dev/null +++ b/B7F6vh_plHw.txt @@ -0,0 +1,255 @@ +Network technologies were developed to connect +components (in this case individual computer + +systems) separated by larger distances, i.e., +distances measured in meters instead of centimeters. + +Communicating over these larger distances +led to different design tradeoffs. + +In early networks, information was sent as +a sequence of bits over the shared communication + +medium. + +The bits were organized into packets, each +containing the address of the destination. + +Packets also included a checksum used to detect +errors in transmission and the protocol supported + +the ability to request the retransmission +of corrupted packets. + +The software controlling the network is divided +into a "stack" of modules, each implementing + +a different communication abstraction. + +The lowest-level physical layer is responsible +for transmitting and receiving an individual + +packet of bits. + +Bit errors are detected and corrected, and +packets with uncorrectable errors are discarded. + +There are different physical-layer modules +available for the different types of physical + +networks. + +The network layer deals with the addressing +and routing of packets. + +Clever routing algorithms find the shortest +communication path through the multi-hop network + +and deal with momentary or long-term outages +on particular network links. + +The transport layer is responsible for providing +the reliable communication of a stream of + +data, dealing with the issues of discarded +or out-of-order packets. + +In an effort to optimize network usage and +limit packet loses due to network congestion, + +the transport layer deals with flow control, +i.e., the rate at which packets are sent. + +A key idea in the networking community is +the notion of building a reliable communication + +channel on top of a "best efforts" packet +network. + +Higher layers of the protocol are designed +so that its possible to recover from errors + +in the lower layers. + +This has proven to be much more cost-effective +and robust than trying to achieve 100% reliability + +at each layer. + +As we saw in the previous section, there are +a lot of electrical issues when trying to + +communicate over a shared wire with multiple +drivers and receivers. + +Slowing down the rate of communication helps +to solve the problems, but "slow" isn't in + +the cards for today's high-performance systems. + +Experience in the network world has shown +that the fastest and least problematic communication + +channels have a single driver communicating +with a single receiver, what's called a point-to-point + +link. + +Using differential signaling is particularly +robust. + +With differential signaling, the receiver +measures the voltage difference across the + +two signaling wires. + +Electrical effects that might induce voltage +noise on one signaling wire will affect the + +other in equal measure, so the voltage difference +will be largely unaffected by most noise. + +Almost all high-performance communication +links use differential signaling. + +If we're sending digital data, does that mean +we also have to send a separate clock signal + +so the receiver knows when to sample the signal +to determine the next bit? + +With some cleverness, it turns out that we +can recover the timing information from the + +received signal assuming we know the nominal +clock period at the transmitter. + +If the transmitter changes the bit its sending +at the rising edge of the transmitter's clock, + +then the receiver can use the transitions +in the received waveform to infer the timing + +for some of the clock edges. + +Then the receiver can use its knowledge of +the transmitter's nominal clock period to + +infer the location of the remaining clock +edges. + +It does this by using a phase-locked loop +to generate a local facsimile of the transmitter's + +clock, using any received transitions to correct +the phase and period of the local clock. + +The transmitter adds a training sequence of +bits at the front of packet to ensure that + +the receiver's phased-lock loop is properly +synchronized before the packet data itself + +is transmitted. + +A unique bit sequence is used to separate +the training signal from the packet data so + +the receiver can tell exactly where the packet +starts + +even if it missed a few training bits while +the clocks were being properly synchronized. + +Once the receiver knows the timing of the +clock edges, it can then sample the incoming + +waveform towards the end of each clock period +to determine the transmitted bit. + +To keep the local clock in sync with the transmitter's +clock, the incoming waveform needs to have + +reasonably frequent transitions. + +But if the transmitter is sending say, all +zeroes, how can we guarantee frequent-enough + +clock edges? + +The trick, invented by IBM, is for the transmitter +to take the stream of message bits and re-encode + +them into a bit stream that is guaranteed +to have transitions no matter what the message + +bits are. + +The most commonly used encoding is 8b10b, +where 8 message bits are encoded into 10 transmitted + +bits, where the encoding guarantees a transition +at least every 6 bit times. + +Of course, the receiver has to reverse the +8b10b encoding to recover the actual message + +bits. + +Pretty neat! + +The benefit of this trick is that we truly +only need to send a single stream of bits. + +The receiver will be able to recover both +the timing information and the data without + +also needing to transmit a separate clock +signal. + +Using these lessons, networks have evolved +from using shared communication channels to + +using point-to-point links. + +Today local-area networks use 10, 100, or +1000 BaseT wiring which includes separate + +differential pairs for sending and receiving, +i.e., each sending or receiving channel is + +unidirectional with a single driver and single +receiver. + +The network uses separate switches and routers +to receive packets from a sender and then + +forward the packets over a point-to-point +link to the next switch, + +and so on, across multiple point-to-point +links until the packet arrives at its destination. + +System-level connections have evolved to use +the same communication strategy: point-to-point + +links with switches for routing packets to +their intended destination. + +Note that communication along each link is +independent, so a network with many links + +can actually support a lot of communication +bandwidth. + +With a small amount of packet buffering in +the switches to deal with momentary contention + +for a particular link, +this is a very effective strategy for moving + +massive amounts of information from one component +to the next. + +In the next section, we'll look at some of +the more interesting details. \ No newline at end of file diff --git a/Bb-bgJdOqig.txt b/Bb-bgJdOqig.txt new file mode 100644 index 0000000000000000000000000000000000000000..0fd4bbcf998965e968992413c7930c8619244046 --- /dev/null +++ b/Bb-bgJdOqig.txt @@ -0,0 +1,1288 @@ +align:start position:0% + +hi welcome back to recitation uh in last + + align:start position:0% +hi welcome back to recitation uh in last + + + align:start position:0% +hi welcome back to recitation uh in last +lecture we talked about finding the + + align:start position:0% +lecture we talked about finding the + + + align:start position:0% +lecture we talked about finding the +derivatives of trigonometric functions + + align:start position:0% +derivatives of trigonometric functions + + + align:start position:0% +derivatives of trigonometric functions +in particular the sign function and the + + align:start position:0% +in particular the sign function and the + + + align:start position:0% +in particular the sign function and the +cosine function so today let's do a an + + align:start position:0% +cosine function so today let's do a an + + + align:start position:0% +cosine function so today let's do a an +example of putting that into practice so + + align:start position:0% +example of putting that into practice so + + + align:start position:0% +example of putting that into practice so +here's a function H ofx = to sin of x + + + align:start position:0% +here's a function H ofx = to sin of x + + + + align:start position:0% +here's a function H ofx = to sin of x + +< TK 3 * cosine of x and I'm asking you + + align:start position:0% +< TK 3 * cosine of x and I'm asking you + + + align:start position:0% +< TK 3 * cosine of x and I'm asking you +to find which values of X have the + + align:start position:0% +to find which values of X have the + + + align:start position:0% +to find which values of X have the +property that the derivative of H ofx is + + align:start position:0% +property that the derivative of H ofx is + + + align:start position:0% +property that the derivative of H ofx is +equal to zero so why don't you take a + + align:start position:0% +equal to zero so why don't you take a + + + align:start position:0% +equal to zero so why don't you take a +minute to think about that work it out + + align:start position:0% +minute to think about that work it out + + + align:start position:0% +minute to think about that work it out +on your own pause the video and we'll + + align:start position:0% +on your own pause the video and we'll + + + align:start position:0% +on your own pause the video and we'll +come back and we'll work it out + + align:start position:0% + + + + align:start position:0% + +together all right so you've hopefully + + align:start position:0% +together all right so you've hopefully + + + align:start position:0% +together all right so you've hopefully +had a chance to look over this problem + + align:start position:0% +had a chance to look over this problem + + + align:start position:0% +had a chance to look over this problem +try it out for yourself now let's see + + align:start position:0% +try it out for yourself now let's see + + + align:start position:0% +try it out for yourself now let's see +how to go about it so we have the + + align:start position:0% +how to go about it so we have the + + + align:start position:0% +how to go about it so we have the +function H ofx it's Al to sin plusk 3 + + align:start position:0% +function H ofx it's Al to sin plusk 3 + + + align:start position:0% +function H ofx it's Al to sin plusk 3 +cosin x and we want to know when its + + align:start position:0% +cosin x and we want to know when its + + + align:start position:0% +cosin x and we want to know when its +derivative is equal to zero so in order + + align:start position:0% +derivative is equal to zero so in order + + + align:start position:0% +derivative is equal to zero so in order +to answer that question we should figure + + align:start position:0% +to answer that question we should figure + + + align:start position:0% +to answer that question we should figure +out what its derivative actually is and + + align:start position:0% +out what its derivative actually is and + + + align:start position:0% +out what its derivative actually is and +try and write down a formula for its + + align:start position:0% +try and write down a formula for its + + + align:start position:0% +try and write down a formula for its +derivative so in this case that's not + + align:start position:0% +derivative so in this case that's not + + + align:start position:0% +derivative so in this case that's not +that bad U if we take a derivative of H + + align:start position:0% +that bad U if we take a derivative of H + + + align:start position:0% +that bad U if we take a derivative of H +well H is a sum of two functions sinx + + align:start position:0% +well H is a sum of two functions sinx + + + align:start position:0% +well H is a sum of two functions sinx +and < TK of 3 cine X and we know that + + align:start position:0% +and < TK of 3 cine X and we know that + + + align:start position:0% +and < TK of 3 cine X and we know that +the derivative a s of a sum is just the + + align:start position:0% +the derivative a s of a sum is just the + + + align:start position:0% +the derivative a s of a sum is just the +sum of the derivatives um so we have + + align:start position:0% +sum of the derivatives um so we have + + + align:start position:0% +sum of the derivatives um so we have +that H Prime of x + + align:start position:0% +that H Prime of x + + + align:start position:0% +that H Prime of x +is equal to D over + + align:start position:0% +is equal to D over + + + align:start position:0% +is equal to D over +DX of + + align:start position:0% +DX of + + + align:start position:0% +DX of +sinx + + align:start position:0% +sinx + + + align:start position:0% +sinx +plus d over DX of < TK 3 + + align:start position:0% +plus d over DX of < TK 3 + + + align:start position:0% +plus d over DX of < TK 3 +* cosine X now uh we learned last time + + align:start position:0% +* cosine X now uh we learned last time + + + align:start position:0% +* cosine X now uh we learned last time +in in lecture that that the derivative + + align:start position:0% +in in lecture that that the derivative + + + align:start position:0% +in in lecture that that the derivative +of sinx is cosine of x and we learned + + align:start position:0% +of sinx is cosine of x and we learned + + + align:start position:0% +of sinx is cosine of x and we learned +the derivative of cosine of x is minus + + align:start position:0% +the derivative of cosine of x is minus + + + align:start position:0% +the derivative of cosine of x is minus +sin x so here we have a constant + + align:start position:0% +sin x so here we have a constant + + + align:start position:0% +sin x so here we have a constant +multiple but by the constant multiple + + align:start position:0% +multiple but by the constant multiple + + + align:start position:0% +multiple but by the constant multiple +rule that just gets pulled out so this + + align:start position:0% +rule that just gets pulled out so this + + + align:start position:0% +rule that just gets pulled out so this +is equal + + align:start position:0% +is equal + + + align:start position:0% +is equal +to cosine + + align:start position:0% +to cosine + + + align:start position:0% +to cosine +xus < TK 3 + + align:start position:0% +xus < TK 3 + + + align:start position:0% +xus < TK 3 +time sinx so this is H Prime of X and + + align:start position:0% +time sinx so this is H Prime of X and + + + align:start position:0% +time sinx so this is H Prime of X and +now we want to solve the equation H + + align:start position:0% +now we want to solve the equation H + + + align:start position:0% +now we want to solve the equation H +Prime of x equals z + + align:start position:0% +Prime of x equals z + + + align:start position:0% +Prime of x equals z +so so we + + align:start position:0% +so so we + + + align:start position:0% +so so we +want to find those values of X such that + + align:start position:0% +want to find those values of X such that + + + align:start position:0% +want to find those values of X such that +cosine x minus < TK 3 + + align:start position:0% +cosine x minus < TK 3 + + + align:start position:0% +cosine x minus < TK 3 +sinx is equal to zero now there are a + + align:start position:0% +sinx is equal to zero now there are a + + + align:start position:0% +sinx is equal to zero now there are a +couple different ways to go about this I + + align:start position:0% +couple different ways to go about this I + + + align:start position:0% +couple different ways to go about this I +think my preferred way is I would add + + align:start position:0% +think my preferred way is I would add + + + align:start position:0% +think my preferred way is I would add +the sare < TK of 3 sinx to one side and + + align:start position:0% +the sare < TK of 3 sinx to one side and + + + align:start position:0% +the sare < TK of 3 sinx to one side and +then I want to get my x's together so I + + align:start position:0% +then I want to get my x's together so I + + + align:start position:0% +then I want to get my x's together so I +would divide by cosine X so that gives + + align:start position:0% +would divide by cosine X so that gives + + + align:start position:0% +would divide by cosine X so that gives +me so on the left side I'll be left with + + align:start position:0% +me so on the left side I'll be left with + + + align:start position:0% +me so on the left side I'll be left with +cosine x ided cosine X so that's just + + align:start position:0% +cosine x ided cosine X so that's just + + + align:start position:0% +cosine x ided cosine X so that's just +one and on the right side I'll have < TK + + align:start position:0% +one and on the right side I'll have < TK + + + align:start position:0% +one and on the right side I'll have < TK + + align:start position:0% + + + align:start position:0% +* sin + + align:start position:0% +* sin + + + align:start position:0% +* sin +x over cine X so that's just < TK + + align:start position:0% +x over cine X so that's just < TK + + + align:start position:0% +x over cine X so that's just < TK +3 * Tan x um or and I can rewrite this + + align:start position:0% +3 * Tan x um or and I can rewrite this + + + align:start position:0% +3 * Tan x um or and I can rewrite this +as tan of X is equal to 1 + + align:start position:0% +as tan of X is equal to 1 + + + align:start position:0% +as tan of X is equal to 1 +/ < TK 3 now to find X here either you + + align:start position:0% +/ < TK 3 now to find X here either you + + + align:start position:0% +/ < TK 3 now to find X here either you +can remember your your special trig + + align:start position:0% +can remember your your special trig + + + align:start position:0% +can remember your your special trig +angles and and know which which values + + align:start position:0% +angles and and know which which values + + + align:start position:0% +angles and and know which which values +of X make this work or you could apply + + align:start position:0% +of X make this work or you could apply + + + align:start position:0% +of X make this work or you could apply +the arct tangent function here so in + + align:start position:0% +the arct tangent function here so in + + + align:start position:0% +the arct tangent function here so in +either case the the + + align:start position:0% +either case the the + + + align:start position:0% +either case the the +simplest solution here is + + align:start position:0% +simplest solution here is + + + align:start position:0% +simplest solution here is +xal pi over 6 so if you like you can + + align:start position:0% +xal pi over 6 so if you like you can + + + align:start position:0% +xal pi over 6 so if you like you can +draw a little right + + align:start position:0% +draw a little right + + + align:start position:0% +draw a little right +triangle you know if this is X if Tan x + + align:start position:0% +triangle you know if this is X if Tan x + + + align:start position:0% +triangle you know if this is X if Tan x +is 1 over < TK of 3 we should have this + + align:start position:0% +is 1 over < TK of 3 we should have this + + + align:start position:0% +is 1 over < TK of 3 we should have this +side being one and this side + + align:start position:0% +side being one and this side + + + align:start position:0% +side being one and this side +being squ < TK of 3 and in and okay in + + align:start position:0% +being squ < TK of 3 and in and okay in + + + align:start position:0% +being squ < TK of 3 and in and okay in +that case in this right triangle the + + align:start position:0% +that case in this right triangle the + + + align:start position:0% +that case in this right triangle the +hypotenuse would be two + + align:start position:0% +hypotenuse would be two + + + align:start position:0% +hypotenuse would be two +and so then you you know would recognize + + align:start position:0% +and so then you you know would recognize + + + align:start position:0% +and so then you you know would recognize +this is a a 30° angle or pi/ 6 radian + + align:start position:0% +this is a a 30° angle or pi/ 6 radian + + + align:start position:0% +this is a a 30° angle or pi/ 6 radian +angle um but one thing to remember is + + align:start position:0% +angle um but one thing to remember is + + + align:start position:0% +angle um but one thing to remember is +that tangent of X is a periodic function + + align:start position:0% +that tangent of X is a periodic function + + + align:start position:0% +that tangent of X is a periodic function +with period Pi so not only is pi over 6 + + align:start position:0% +with period Pi so not only is pi over 6 + + + align:start position:0% +with period Pi so not only is pi over 6 +a solution but pi over 6 plus pi is a + + align:start position:0% +a solution but pi over 6 plus pi is a + + + align:start position:0% +a solution but pi over 6 plus pi is a +solution um so that's 7 pi/ 6 or pi over + + align:start position:0% +solution um so that's 7 pi/ 6 or pi over + + + align:start position:0% +solution um so that's 7 pi/ 6 or pi over +6 + 2 pi which is 13 pi over 6 or pi + + align:start position:0% +6 + 2 pi which is 13 pi over 6 or pi + + + align:start position:0% +6 + 2 pi which is 13 pi over 6 or pi +over 6 minus Pi which is min -5 + + align:start position:0% +over 6 minus Pi which is min -5 + + + align:start position:0% +over 6 minus Pi which is min -5 +pi over 6 Etc so there're actually + + align:start position:0% +pi over 6 Etc so there're actually + + + align:start position:0% +pi over 6 Etc so there're actually +infinitely many solutions they're + + align:start position:0% +infinitely many solutions they're + + + align:start position:0% +infinitely many solutions they're +they're given by pi over 6 plus an + + align:start position:0% +they're given by pi over 6 plus an + + + align:start position:0% +they're given by pi over 6 plus an +arbitrary multiple of Pi uh so then + + align:start position:0% +arbitrary multiple of Pi uh so then + + + align:start position:0% +arbitrary multiple of Pi uh so then +we're done um so I do want to mention + + align:start position:0% +we're done um so I do want to mention + + + align:start position:0% +we're done um so I do want to mention +though that there's a there's another + + align:start position:0% +though that there's a there's another + + + align:start position:0% +though that there's a there's another +approach to this question which is we + + align:start position:0% +approach to this question which is we + + + align:start position:0% +approach to this question which is we +can start by multiplying this expression + + align:start position:0% +can start by multiplying this expression + + + align:start position:0% +can start by multiplying this expression +for H of X so if you look at h of X It's + + align:start position:0% +for H of X so if you look at h of X It's + + + align:start position:0% +for H of X so if you look at h of X It's +s of X Plus s of 3 * cosine X um it + + align:start position:0% +s of X Plus s of 3 * cosine X um it + + + align:start position:0% +s of X Plus s of 3 * cosine X um it +resembles closely one of your uh + + align:start position:0% +resembles closely one of your uh + + + align:start position:0% +resembles closely one of your uh +trigonometric identities that that you + + align:start position:0% +trigonometric identities that that you + + + align:start position:0% +trigonometric identities that that you +know about um so in particular to make + + align:start position:0% +know about um so in particular to make + + + align:start position:0% +know about um so in particular to make +it resemble it even more I can multiply + + align:start position:0% +it resemble it even more I can multiply + + + align:start position:0% +it resemble it even more I can multiply +and divide by two so I can rewrite h ofx + + align:start position:0% +and divide by two so I can rewrite h ofx + + + align:start position:0% +and divide by two so I can rewrite h ofx += 2 + + align:start position:0% += 2 + + + align:start position:0% += 2 +* 12 + + align:start position:0% +* 12 + + + align:start position:0% +* 12 +sinx + < TK 3 / + + align:start position:0% +sinx + < TK 3 / + + + align:start position:0% +sinx + < TK 3 / +2 * cosine X and now 12 is equal to cine + + align:start position:0% +2 * cosine X and now 12 is equal to cine + + + align:start position:0% +2 * cosine X and now 12 is equal to cine +of pi/ 3 and square 32 is equal to S of + + align:start position:0% +of pi/ 3 and square 32 is equal to S of + + + align:start position:0% +of pi/ 3 and square 32 is equal to S of +pi over 3 so I can rewrite this as 2 + + align:start position:0% +pi over 3 so I can rewrite this as 2 + + + align:start position:0% +pi over 3 so I can rewrite this as 2 +* what did I say I said cosine pi over + + align:start position:0% +* what did I say I said cosine pi over + + + align:start position:0% +* what did I say I said cosine pi over +3 sin x plus sin pi over 3 cosine X and + + align:start position:0% +3 sin x plus sin pi over 3 cosine X and + + + align:start position:0% +3 sin x plus sin pi over 3 cosine X and +this is exactly what you get when you do + + align:start position:0% +this is exactly what you get when you do + + + align:start position:0% +this is exactly what you get when you do +the angle addition formula for S um this + + align:start position:0% +the angle addition formula for S um this + + + align:start position:0% +the angle addition formula for S um this +is the expanded out form and so we can + + align:start position:0% +is the expanded out form and so we can + + + align:start position:0% +is the expanded out form and so we can +apply it in reverse and get that this is + + align:start position:0% +apply it in reverse and get that this is + + + align:start position:0% +apply it in reverse and get that this is +equal to 2 * s + + align:start position:0% +equal to 2 * s + + + align:start position:0% +equal to 2 * s +of x + + align:start position:0% + + + + align:start position:0% + ++ pi over 3 so so far we haven't done + + align:start position:0% ++ pi over 3 so so far we haven't done + + + align:start position:0% ++ pi over 3 so so far we haven't done +any calculus we've just done so so in + + align:start position:0% +any calculus we've just done so so in + + + align:start position:0% +any calculus we've just done so so in +this solution our first solution we did + + align:start position:0% +this solution our first solution we did + + + align:start position:0% +this solution our first solution we did +some calculus first and then some + + align:start position:0% +some calculus first and then some + + + align:start position:0% +some calculus first and then some +algebra and trigonometry so so far we've + + align:start position:0% +algebra and trigonometry so so far we've + + + align:start position:0% +algebra and trigonometry so so far we've +just done some algebra and trigonometry + + align:start position:0% +just done some algebra and trigonometry + + + align:start position:0% +just done some algebra and trigonometry +um + + align:start position:0% +um + + + align:start position:0% +um +now the points where H Prime of X is + + align:start position:0% +now the points where H Prime of X is + + + align:start position:0% +now the points where H Prime of X is +equal to zero are the points where the + + align:start position:0% +equal to zero are the points where the + + + align:start position:0% +equal to zero are the points where the +graph of this function has a horizontal + + align:start position:0% +graph of this function has a horizontal + + + align:start position:0% +graph of this function has a horizontal +tangent line so either you can compute + + align:start position:0% +tangent line so either you can compute + + + align:start position:0% +tangent line so either you can compute +its derivative using your your rules or + + align:start position:0% +its derivative using your your rules or + + + align:start position:0% +its derivative using your your rules or +by the definition or you can just say oh + + align:start position:0% +by the definition or you can just say oh + + + align:start position:0% +by the definition or you can just say oh +we know what this graph looks like so + + align:start position:0% +we know what this graph looks like so + + + align:start position:0% +we know what this graph looks like so +I've I've sort of drawn a schematic up + + align:start position:0% +I've I've sort of drawn a schematic up + + + align:start position:0% +I've I've sort of drawn a schematic up +here so this is a graph this is this + + align:start position:0% +here so this is a graph this is this + + + align:start position:0% +here so this is a graph this is this +graph is okay so this is the graph y = + + align:start position:0% +graph is okay so this is the graph y = + + + align:start position:0% +graph is okay so this is the graph y = +2 sin of x + pi over 3 it's what you get + + align:start position:0% +2 sin of x + pi over 3 it's what you get + + + align:start position:0% +2 sin of x + pi over 3 it's what you get +if you take the graph yal sinx and you + + align:start position:0% +if you take the graph yal sinx and you + + + align:start position:0% +if you take the graph yal sinx and you +shift it left by pi over 3 and you you + + align:start position:0% +shift it left by pi over 3 and you you + + + align:start position:0% +shift it left by pi over 3 and you you +scale it up by a factor of two so this + + align:start position:0% +scale it up by a factor of two so this + + + align:start position:0% +scale it up by a factor of two so this +this here is at x = minus pi over 3 this + + align:start position:0% +this here is at x = minus pi over 3 this + + + align:start position:0% +this here is at x = minus pi over 3 this +root is x = 2 pi over 3 um and the + + align:start position:0% +root is x = 2 pi over 3 um and the + + + align:start position:0% +root is x = 2 pi over 3 um and the +points we're interested in are the + + align:start position:0% +points we're interested in are the + + + align:start position:0% +points we're interested in are the +points where there's a horizontal + + align:start position:0% +points where there's a horizontal + + + align:start position:0% +points where there's a horizontal +tangent line where the derivative is + + align:start position:0% +tangent line where the derivative is + + + align:start position:0% +tangent line where the derivative is +zero and so there's one of these right + + align:start position:0% +zero and so there's one of these right + + + align:start position:0% +zero and so there's one of these right +at this value which is pi over 6 and + + align:start position:0% +at this value which is pi over 6 and + + + align:start position:0% +at this value which is pi over 6 and +then the second one is this is that + + align:start position:0% +then the second one is this is that + + + align:start position:0% +then the second one is this is that +minimum there so that happens at x = 7 + + align:start position:0% +minimum there so that happens at x = 7 + + + align:start position:0% +minimum there so that happens at x = 7 +piun 6 Pi 6 because for the usual sign + + align:start position:0% +piun 6 Pi 6 because for the usual sign + + + align:start position:0% +piun 6 Pi 6 because for the usual sign +function it happens at pi over 2 but we + + align:start position:0% +function it happens at pi over 2 but we + + + align:start position:0% +function it happens at pi over 2 but we +shifted everything left by pi over 3 and + + align:start position:0% +shifted everything left by pi over 3 and + + + align:start position:0% +shifted everything left by pi over 3 and +so pi over 2 minus pi over 3 is pi over + + align:start position:0% +so pi over 2 minus pi over 3 is pi over + + + align:start position:0% +so pi over 2 minus pi over 3 is pi over +6 and here for for this for just yals + + align:start position:0% +6 and here for for this for just yals + + + align:start position:0% +6 and here for for this for just yals +sinx this minimum would happen at 3 pi + + align:start position:0% +sinx this minimum would happen at 3 pi + + + align:start position:0% +sinx this minimum would happen at 3 pi +over 2 but we've shifted it left by pi + + align:start position:0% +over 2 but we've shifted it left by pi + + + align:start position:0% +over 2 but we've shifted it left by pi +over 3 um and so on you know every every + + align:start position:0% +over 3 um and so on you know every every + + + align:start position:0% +over 3 um and so on you know every every +there's a there's another trough over + + align:start position:0% +there's a there's another trough over + + + align:start position:0% +there's a there's another trough over +here and another Peak over there and and + + align:start position:0% +here and another Peak over there and and + + + align:start position:0% +here and another Peak over there and and +so on um so that's the the second way + + align:start position:0% +so on um so that's the the second way + + + align:start position:0% +so on um so that's the the second way +you can do this question um using this + + align:start position:0% +you can do this question um using this + + + align:start position:0% +you can do this question um using this +this cute trig identity here and that's + + align:start position:0% +this cute trig identity here and that's + + + align:start position:0% +this cute trig identity here and that's +that \ No newline at end of file diff --git a/CCoTAyZ14XM.txt b/CCoTAyZ14XM.txt new file mode 100644 index 0000000000000000000000000000000000000000..9df3487ea1f0ac06e8b251f426344ab50d412ee9 --- /dev/null +++ b/CCoTAyZ14XM.txt @@ -0,0 +1,2152 @@ +align:start position:0% + +hi welcome back to recitation in lecture + + align:start position:0% +hi welcome back to recitation in lecture + + + align:start position:0% +hi welcome back to recitation in lecture +you've been learning about flux and + + align:start position:0% +you've been learning about flux and + + + align:start position:0% +you've been learning about flux and +surface integrals in the Divergence + + align:start position:0% +surface integrals in the Divergence + + + align:start position:0% +surface integrals in the Divergence +Theorem and I have a nice problem about + + align:start position:0% +Theorem and I have a nice problem about + + + align:start position:0% +Theorem and I have a nice problem about +that for you here so I've got this field + + align:start position:0% +that for you here so I've got this field + + + align:start position:0% +that for you here so I've got this field +F it's a little bit ugly right all right + + align:start position:0% +F it's a little bit ugly right all right + + + align:start position:0% +F it's a little bit ugly right all right +so it's its coordinates are X to 4 y - + + align:start position:0% +so it's its coordinates are X to 4 y - + + + align:start position:0% +so it's its coordinates are X to 4 y - +2x Cub y^ 2 and z^ squ and it's passing + + align:start position:0% +2x Cub y^ 2 and z^ squ and it's passing + + + align:start position:0% +2x Cub y^ 2 and z^ squ and it's passing +through the surface of a solid that's + + align:start position:0% +through the surface of a solid that's + + + align:start position:0% +through the surface of a solid that's +bounded by the plane Z equals z by the + + align:start position:0% +bounded by the plane Z equals z by the + + + align:start position:0% +bounded by the plane Z equals z by the +plane zal H and by the by the surface + + align:start position:0% +plane zal H and by the by the surface + + + align:start position:0% +plane zal H and by the by the surface +x^2 + y^2 = R2 so often we call this + + align:start position:0% +x^2 + y^2 = R2 so often we call this + + + align:start position:0% +x^2 + y^2 = R2 so often we call this +solid a cylinder um so it's got its + + align:start position:0% +solid a cylinder um so it's got its + + + align:start position:0% +solid a cylinder um so it's got its +bottom surface in the plane Z equals z + + align:start position:0% +bottom surface in the plane Z equals z + + + align:start position:0% +bottom surface in the plane Z equals z +and its top surface in the plane Z + + align:start position:0% +and its top surface in the plane Z + + + align:start position:0% +and its top surface in the plane Z +equals H and it's got a circular base + + align:start position:0% +equals H and it's got a circular base + + + align:start position:0% +equals H and it's got a circular base +with radius R there um so what I'd like + + align:start position:0% +with radius R there um so what I'd like + + + align:start position:0% +with radius R there um so what I'd like +you to do is to compute the flux of this + + align:start position:0% +you to do is to compute the flux of this + + + align:start position:0% +you to do is to compute the flux of this +field F through this through this + + align:start position:0% +field F through this through this + + + align:start position:0% +field F through this through this +cylinder um so I'll I'll point out + + align:start position:0% +cylinder um so I'll I'll point out + + + align:start position:0% +cylinder um so I'll I'll point out +before I before I let you at it that + + align:start position:0% +before I before I let you at it that + + + align:start position:0% +before I before I let you at it that +that this is you know to compute this as + + align:start position:0% +that this is you know to compute this as + + + align:start position:0% +that this is you know to compute this as +a surface integral you could do it you + + align:start position:0% +a surface integral you could do it you + + + align:start position:0% +a surface integral you could do it you +could do it if you really want an + + align:start position:0% +could do it if you really want an + + + align:start position:0% +could do it if you really want an +exercise in nasty arithmetic I invite + + align:start position:0% +exercise in nasty arithmetic I invite + + + align:start position:0% +exercise in nasty arithmetic I invite +you to do it but you might be able to + + align:start position:0% +you to do it but you might be able to + + + align:start position:0% +you to do it but you might be able to +think of a of a way to do this that + + align:start position:0% +think of a of a way to do this that + + + align:start position:0% +think of a of a way to do this that +requires less effort than than + + align:start position:0% +requires less effort than than + + + align:start position:0% +requires less effort than than +parameterizing the three surfaces and + + align:start position:0% +parameterizing the three surfaces and + + + align:start position:0% +parameterizing the three surfaces and +integrating and so on so I'll leave with + + align:start position:0% +integrating and so on so I'll leave with + + + align:start position:0% +integrating and so on so I'll leave with +that why don't you pause the video um + + align:start position:0% +that why don't you pause the video um + + + align:start position:0% +that why don't you pause the video um +work this one out come back and we can + + align:start position:0% +work this one out come back and we can + + + align:start position:0% +work this one out come back and we can +work on it + + align:start position:0% + + + + align:start position:0% + +together hopefully you had some luck + + align:start position:0% +together hopefully you had some luck + + + align:start position:0% +together hopefully you had some luck +working on this problem right before I + + align:start position:0% +working on this problem right before I + + + align:start position:0% +working on this problem right before I +left I mentioned that you were Computing + + align:start position:0% +left I mentioned that you were Computing + + + align:start position:0% +left I mentioned that you were Computing +a flux uh through a through a surface + + align:start position:0% +a flux uh through a through a surface + + + align:start position:0% +a flux uh through a through a surface +here but that doing it as a surface + + align:start position:0% +here but that doing it as a surface + + + align:start position:0% +here but that doing it as a surface +integral was maybe not the best way to + + align:start position:0% +integral was maybe not the best way to + + + align:start position:0% +integral was maybe not the best way to +go and so you know even without that + + align:start position:0% +go and so you know even without that + + + align:start position:0% +go and so you know even without that +hint probably many of you realize that + + align:start position:0% +hint probably many of you realize that + + + align:start position:0% +hint probably many of you realize that +really the way that we want to go about + + align:start position:0% +really the way that we want to go about + + + align:start position:0% +really the way that we want to go about +this problem is with the Divergence + + align:start position:0% +this problem is with the Divergence + + + align:start position:0% +this problem is with the Divergence +Theorem okay so the Divergence Theorem + + align:start position:0% +Theorem okay so the Divergence Theorem + + + align:start position:0% +Theorem okay so the Divergence Theorem +says + + align:start position:0% +says + + + align:start position:0% +says +that in our case the Divergence Theorem + + align:start position:0% +that in our case the Divergence Theorem + + + align:start position:0% +that in our case the Divergence Theorem +I'm just abbreviating it div THM here + + align:start position:0% +I'm just abbreviating it div THM here + + + align:start position:0% +I'm just abbreviating it div THM here +says that the that the double integral + + align:start position:0% +says that the that the double integral + + + align:start position:0% +says that the that the double integral +over the surface of f Dot + + align:start position:0% +over the surface of f Dot + + + align:start position:0% +over the surface of f Dot +N D surface area so that's the so s here + + align:start position:0% +N D surface area so that's the so s here + + + align:start position:0% +N D surface area so that's the so s here +is the surface of this solid um so the + + align:start position:0% +is the surface of this solid um so the + + + align:start position:0% +is the surface of this solid um so the +Divergence Theorem says that this that + + align:start position:0% +Divergence Theorem says that this that + + + align:start position:0% +Divergence Theorem says that this that +this double integral which is or this + + align:start position:0% +this double integral which is or this + + + align:start position:0% +this double integral which is or this +surface integral rather which is the + + align:start position:0% +surface integral rather which is the + + + align:start position:0% +surface integral rather which is the +flux that we're interested in is equal + + align:start position:0% +flux that we're interested in is equal + + + align:start position:0% +flux that we're interested in is equal +to the triple integral over the solid + + align:start position:0% +to the triple integral over the solid + + + align:start position:0% +to the triple integral over the solid +region D so that's bounded by the + + align:start position:0% +region D so that's bounded by the + + + align:start position:0% +region D so that's bounded by the +surface so that's the solid cylinder + + align:start position:0% +surface so that's the solid cylinder + + + align:start position:0% +surface so that's the solid cylinder +here is equal to the triple integral + + align:start position:0% +here is equal to the triple integral + + + align:start position:0% +here is equal to the triple integral +over D + + align:start position:0% +over D + + + align:start position:0% +over D +of div F + + align:start position:0% +of div F + + + align:start position:0% +of div F +DV okay + + align:start position:0% +DV okay + + + align:start position:0% +DV okay +so in our case this is nice because in + + align:start position:0% +so in our case this is nice because in + + + align:start position:0% +so in our case this is nice because in +fact this solid region D is an easier to + + align:start position:0% +fact this solid region D is an easier to + + + align:start position:0% +fact this solid region D is an easier to +understand or easy to easier to Grapple + + align:start position:0% +understand or easy to easier to Grapple + + + align:start position:0% +understand or easy to easier to Grapple +with region than than the surface that + + align:start position:0% +with region than than the surface that + + + align:start position:0% +with region than than the surface that +we started with right it's it's just one + + align:start position:0% +we started with right it's it's just one + + + align:start position:0% +we started with right it's it's just one +solid piece whereas that's easy to + + align:start position:0% +solid piece whereas that's easy to + + + align:start position:0% +solid piece whereas that's easy to +parameterize in fact you know that's + + align:start position:0% +parameterize in fact you know that's + + + align:start position:0% +parameterize in fact you know that's +easy to describe in in especially in + + align:start position:0% +easy to describe in in especially in + + + align:start position:0% +easy to describe in in especially in +cylindrical coordinates but also in + + align:start position:0% +cylindrical coordinates but also in + + + align:start position:0% +cylindrical coordinates but also in +rectangular coordinates um whereas the + + align:start position:0% +rectangular coordinates um whereas the + + + align:start position:0% +rectangular coordinates um whereas the +surface s if we wanted to talk about it + + align:start position:0% +surface s if we wanted to talk about it + + + align:start position:0% +surface s if we wanted to talk about it +we need to split it up into three pieces + + align:start position:0% +we need to split it up into three pieces + + + align:start position:0% +we need to split it up into three pieces +and we'd need to parameterize it and + + align:start position:0% +and we'd need to parameterize it and + + + align:start position:0% +and we'd need to parameterize it and +that's kind of a hassle relatively + + align:start position:0% +that's kind of a hassle relatively + + + align:start position:0% +that's kind of a hassle relatively +speaking um also the Divergence of this + + align:start position:0% +speaking um also the Divergence of this + + + align:start position:0% +speaking um also the Divergence of this +field f is is a lot simpler than the + + align:start position:0% +field f is is a lot simpler than the + + + align:start position:0% +field f is is a lot simpler than the +field itself if you if we go and look at + + align:start position:0% +field itself if you if we go and look at + + + align:start position:0% +field itself if you if we go and look at +this field right this is a field all all + + align:start position:0% +this field right this is a field all all + + + align:start position:0% +this field right this is a field all all +of its components are pols um to compute + + align:start position:0% +of its components are pols um to compute + + + align:start position:0% +of its components are pols um to compute +its Divergence we take derivatives of + + align:start position:0% +its Divergence we take derivatives of + + + align:start position:0% +its Divergence we take derivatives of +all of them um and so that makes their + + align:start position:0% +all of them um and so that makes their + + + align:start position:0% +all of them um and so that makes their +degrees lower and and then we just add + + align:start position:0% +degrees lower and and then we just add + + + align:start position:0% +degrees lower and and then we just add +them it's it's a little bit life is a + + align:start position:0% +them it's it's a little bit life is a + + + align:start position:0% +them it's it's a little bit life is a +little bit simpler um so okay so so so + + align:start position:0% +little bit simpler um so okay so so so + + + align:start position:0% +little bit simpler um so okay so so so +so this process using the Divergence + + align:start position:0% +so this process using the Divergence + + + align:start position:0% +so this process using the Divergence +Theorem is going to make this this Our + + align:start position:0% +Theorem is going to make this this Our + + + align:start position:0% +Theorem is going to make this this Our +Lives easier it's going to make this + + align:start position:0% +Lives easier it's going to make this + + + align:start position:0% +Lives easier it's going to make this +kind of nasty surface integral into an + + align:start position:0% +kind of nasty surface integral into an + + + align:start position:0% +kind of nasty surface integral into an +easy to compute uh triple integral so + + align:start position:0% +easy to compute uh triple integral so + + + align:start position:0% +easy to compute uh triple integral so +let's let's see actually how it does so + + align:start position:0% +let's let's see actually how it does so + + + align:start position:0% +let's let's see actually how it does so +let's let's compute div F first um so we + + align:start position:0% +let's let's compute div F first um so we + + + align:start position:0% +let's let's compute div F first um so we +know what the integrand is so div F all + + align:start position:0% +know what the integrand is so div F all + + + align:start position:0% +know what the integrand is so div F all +right so it's so we look we need to look + + align:start position:0% +right so it's so we look we need to look + + + align:start position:0% +right so it's so we look we need to look +at the components of F and so we need to + + align:start position:0% +at the components of F and so we need to + + + align:start position:0% +at the components of F and so we need to +take the partial of the first one with + + align:start position:0% +take the partial of the first one with + + + align:start position:0% +take the partial of the first one with +respect to X so that's X to 4th y with + + align:start position:0% +respect to X so that's X to 4th y with + + + align:start position:0% +respect to X so that's X to 4th y with +respect to X so put that down over here + + align:start position:0% +respect to X so put that down over here + + + align:start position:0% +respect to X so put that down over here +that's 4 x cubed y we just treat y as a + + align:start position:0% +that's 4 x cubed y we just treat y as a + + + align:start position:0% +that's 4 x cubed y we just treat y as a +constant okay so now we come back and we + + align:start position:0% +constant okay so now we come back and we + + + align:start position:0% +constant okay so now we come back and we +need to look at the second one so it's - + + align:start position:0% +need to look at the second one so it's - + + + align:start position:0% +need to look at the second one so it's - +2x Cub y^ 2 and it's the second one we + + align:start position:0% +2x Cub y^ 2 and it's the second one we + + + align:start position:0% +2x Cub y^ 2 and it's the second one we +take it's partial with respect to Y so + + align:start position:0% +take it's partial with respect to Y so + + + align:start position:0% +take it's partial with respect to Y so +okay so that's going to be - 2x Cub * 2 + + align:start position:0% +okay so that's going to be - 2x Cub * 2 + + + align:start position:0% +okay so that's going to be - 2x Cub * 2 +y so that's going to be Min + + align:start position:0% +y so that's going to be Min + + + align:start position:0% +y so that's going to be Min +-4 x cubed Y and then the last okay so + + align:start position:0% +-4 x cubed Y and then the last okay so + + + align:start position:0% +-4 x cubed Y and then the last okay so +then we come back and we look at the + + align:start position:0% +then we come back and we look at the + + + align:start position:0% +then we come back and we look at the +last component and that's z^ 2 and so we + + align:start position:0% +last component and that's z^ 2 and so we + + + align:start position:0% +last component and that's z^ 2 and so we +need to take its partial with respect to + + align:start position:0% +need to take its partial with respect to + + + align:start position:0% +need to take its partial with respect to +Z so in this case that's just 2 Z and so + + align:start position:0% +Z so in this case that's just 2 Z and so + + + align:start position:0% +Z so in this case that's just 2 Z and so +we add that on as well plus 2 Z and in + + align:start position:0% +we add that on as well plus 2 Z and in + + + align:start position:0% +we add that on as well plus 2 Z and in +this case not only are these polinomial + + align:start position:0% +this case not only are these polinomial + + + align:start position:0% +this case not only are these polinomial +simpler than the than the coordinates of + + align:start position:0% +simpler than the than the coordinates of + + + align:start position:0% +simpler than the than the coordinates of +F that we had but in fact two of them + + align:start position:0% +F that we had but in fact two of them + + + align:start position:0% +F that we had but in fact two of them +you know there's we've got some + + align:start position:0% +you know there's we've got some + + + align:start position:0% +you know there's we've got some +simplification here life it it gets + + align:start position:0% +simplification here life it it gets + + + align:start position:0% +simplification here life it it gets +really really simple so so in fact this + + align:start position:0% +really really simple so so in fact this + + + align:start position:0% +really really simple so so in fact this +is just going to work out to 2 Z so the + + align:start position:0% +is just going to work out to 2 Z so the + + + align:start position:0% +is just going to work out to 2 Z so the +Divergence here is is very simple + + align:start position:0% +Divergence here is is very simple + + + align:start position:0% +Divergence here is is very simple +compared with the function f more simple + + align:start position:0% +compared with the function f more simple + + + align:start position:0% +compared with the function f more simple +than we sort of have a right to expect + + align:start position:0% +than we sort of have a right to expect + + + align:start position:0% +than we sort of have a right to expect +but but in any case good it's nice to + + align:start position:0% +but but in any case good it's nice to + + + align:start position:0% +but but in any case good it's nice to +work with um okay so that's the + + align:start position:0% +work with um okay so that's the + + + align:start position:0% +work with um okay so that's the +Divergence uh so now so the thing that I + + align:start position:0% +Divergence uh so now so the thing that I + + + align:start position:0% +Divergence uh so now so the thing that I +want so I'm going to I'm going to write + + align:start position:0% +want so I'm going to I'm going to write + + + align:start position:0% +want so I'm going to I'm going to write +this is the flux these integrals that + + align:start position:0% +this is the flux these integrals that + + + align:start position:0% +this is the flux these integrals that +we're interested in this this surface + + align:start position:0% +we're interested in this this surface + + + align:start position:0% +we're interested in this this surface +integral and then by the Divergence + + align:start position:0% +integral and then by the Divergence + + + align:start position:0% +integral and then by the Divergence +Theorem that's the same as this triple + + align:start position:0% +Theorem that's the same as this triple + + + align:start position:0% +Theorem that's the same as this triple +integral okay so the Divergence is this + + align:start position:0% +integral okay so the Divergence is this + + + align:start position:0% +integral okay so the Divergence is this +2 Z so the flux is what I get when I + + align:start position:0% +2 Z so the flux is what I get when I + + + align:start position:0% +2 Z so the flux is what I get when I +just put that in here so + + align:start position:0% +just put that in here so + + + align:start position:0% +just put that in here so +flux is equal to so it's equal to the + + align:start position:0% +flux is equal to so it's equal to the + + + align:start position:0% +flux is equal to so it's equal to the +triple + + align:start position:0% +triple + + + align:start position:0% +triple +integral over our solid of of 2 Z DV + + align:start position:0% +integral over our solid of of 2 Z DV + + + align:start position:0% +integral over our solid of of 2 Z DV +okay so I've I've left some stuff out of + + align:start position:0% +okay so I've I've left some stuff out of + + + align:start position:0% +okay so I've I've left some stuff out of +this and so because I'm going to start + + align:start position:0% +this and so because I'm going to start + + + align:start position:0% +this and so because I'm going to start +I'm going to start + + align:start position:0% +I'm going to start + + + align:start position:0% +I'm going to start +writing down the bounds and writing this + + align:start position:0% +writing down the bounds and writing this + + + align:start position:0% +writing down the bounds and writing this +down as an iterated integral now um okay + + align:start position:0% +down as an iterated integral now um okay + + + align:start position:0% +down as an iterated integral now um okay +so we so we have to choose some some + + align:start position:0% +so we so we have to choose some some + + + align:start position:0% +so we so we have to choose some some +coordinate system in which to to + + align:start position:0% +coordinate system in which to to + + + align:start position:0% +coordinate system in which to to +integrate over this solid and so there + + align:start position:0% +integrate over this solid and so there + + + align:start position:0% +integrate over this solid and so there +are you know we have we have three kind + + align:start position:0% +are you know we have we have three kind + + + align:start position:0% +are you know we have we have three kind +of natural choices that we always look + + align:start position:0% +of natural choices that we always look + + + align:start position:0% +of natural choices that we always look +back to there's rectangular coordinates + + align:start position:0% +back to there's rectangular coordinates + + + align:start position:0% +back to there's rectangular coordinates +and cylindrical coordinates and + + align:start position:0% +and cylindrical coordinates and + + + align:start position:0% +and cylindrical coordinates and +spherical coordinates so spherical + + align:start position:0% +spherical coordinates so spherical + + + align:start position:0% +spherical coordinates so spherical +coordinates seems pretty clearly + + align:start position:0% +coordinates seems pretty clearly + + + align:start position:0% +coordinates seems pretty clearly +inappropriate rectangular and + + align:start position:0% +inappropriate rectangular and + + + align:start position:0% +inappropriate rectangular and +cylindrical you know you could try and + + align:start position:0% +cylindrical you know you could try and + + + align:start position:0% +cylindrical you know you could try and +do it in rectangular + + align:start position:0% +do it in rectangular + + + align:start position:0% +do it in rectangular +that's not it's not horrible but this is + + align:start position:0% +that's not it's not horrible but this is + + + align:start position:0% +that's not it's not horrible but this is +a cylinder right I mean it it's crying + + align:start position:0% +a cylinder right I mean it it's crying + + + align:start position:0% +a cylinder right I mean it it's crying +out for us to use cylindrical + + align:start position:0% +out for us to use cylindrical + + + align:start position:0% +out for us to use cylindrical +coordinates so so let's use cylindrical + + align:start position:0% +coordinates so so let's use cylindrical + + + align:start position:0% +coordinates so so let's use cylindrical +coordinates so if we're going to use + + align:start position:0% +coordinates so if we're going to use + + + align:start position:0% +coordinates so if we're going to use +cylindrical coordinates what we get here + + align:start position:0% +cylindrical coordinates what we get here + + + align:start position:0% +cylindrical coordinates what we get here +for DV so we we need a z an r and a + + align:start position:0% +for DV so we we need a z an r and a + + + align:start position:0% +for DV so we we need a z an r and a +Theta but but remember there's this + + align:start position:0% +Theta but but remember there's this + + + align:start position:0% +Theta but but remember there's this +extra factor of R so it's going to be 2z + + align:start position:0% +extra factor of R so it's going to be 2z + + + align:start position:0% +extra factor of R so it's going to be 2z +times okay so it's R DZ Dr D Theta right + + align:start position:0% +times okay so it's R DZ Dr D Theta right + + + align:start position:0% +times okay so it's R DZ Dr D Theta right +this is DV this R DZ d d Theta + + align:start position:0% +this is DV this R DZ d d Theta + + + align:start position:0% +this is DV this R DZ d d Theta +part so that's what DV is when we use + + align:start position:0% +part so that's what DV is when we use + + + align:start position:0% +part so that's what DV is when we use +cylindrical coordinates okay so now + + align:start position:0% +cylindrical coordinates okay so now + + + align:start position:0% +cylindrical coordinates okay so now +let's uh let's figure out what the + + align:start position:0% +let's uh let's figure out what the + + + align:start position:0% +let's uh let's figure out what the +bounds are so let's go look at this + + align:start position:0% +bounds are so let's go look at this + + + align:start position:0% +bounds are so let's go look at this +cylinder that we had over here um so + + align:start position:0% +cylinder that we had over here um so + + + align:start position:0% +cylinder that we had over here um so +let's see so it's got so it's bounded + + align:start position:0% +let's see so it's got so it's bounded + + + align:start position:0% +let's see so it's got so it's bounded +between Z equals z the bottom surface + + align:start position:0% +between Z equals z the bottom surface + + + align:start position:0% +between Z equals z the bottom surface +and Z equals H the top surface okay well + + align:start position:0% +and Z equals H the top surface okay well + + + align:start position:0% +and Z equals H the top surface okay well +that's so that's easy enough that's + + align:start position:0% +that's so that's easy enough that's + + + align:start position:0% +that's so that's easy enough that's +that's what the bounds on ZR so okay so + + align:start position:0% +that's what the bounds on ZR so okay so + + + align:start position:0% +that's what the bounds on ZR so okay so +let's put those in so Z that's the + + align:start position:0% +let's put those in so Z that's the + + + align:start position:0% +let's put those in so Z that's the +innermost one so that's going from 0 to + + align:start position:0% +innermost one so that's going from 0 to + + + align:start position:0% +innermost one so that's going from 0 to +H okay how about the next one so the + + align:start position:0% +H okay how about the next one so the + + + align:start position:0% +H okay how about the next one so the +next one is R so let's go back over here + + align:start position:0% +next one is R so let's go back over here + + + align:start position:0% +next one is R so let's go back over here +so R um is the is the radius here after + + align:start position:0% +so R um is the is the radius here after + + + align:start position:0% +so R um is the is the radius here after +we you know we we project it down um we + + align:start position:0% +we you know we we project it down um we + + + align:start position:0% +we you know we we project it down um we +just get this circle of radius Big R + + align:start position:0% +just get this circle of radius Big R + + + align:start position:0% +just get this circle of radius Big R +centered at the origin so little r is + + align:start position:0% +centered at the origin so little r is + + + align:start position:0% +centered at the origin so little r is +going from zero to Big R and Theta is + + align:start position:0% +going from zero to Big R and Theta is + + + align:start position:0% +going from zero to Big R and Theta is +going you know it's the circle it's the + + align:start position:0% +going you know it's the circle it's the + + + align:start position:0% +going you know it's the circle it's the +whole circle so Theta is going from 0 to + + align:start position:0% +whole circle so Theta is going from 0 to + + + align:start position:0% +whole circle so Theta is going from 0 to +2 pi so okay so cylinders really easy to + + align:start position:0% +2 pi so okay so cylinders really easy to + + + align:start position:0% +2 pi so okay so cylinders really easy to +describe what they look like in + + align:start position:0% +describe what they look like in + + + align:start position:0% +describe what they look like in +cylindrical coordinates so let's put + + align:start position:0% +cylindrical coordinates so let's put + + + align:start position:0% +cylindrical coordinates so let's put +those in so little r is going from0 to + + align:start position:0% +those in so little r is going from0 to + + + align:start position:0% +those in so little r is going from0 to +Big R and Theta is going from zero to 2 + + align:start position:0% +Big R and Theta is going from zero to 2 + + + align:start position:0% +Big R and Theta is going from zero to 2 +pi 2 + + align:start position:0% +pi 2 + + + align:start position:0% +pi 2 +pi okay wonderful now we just have to + + align:start position:0% +pi okay wonderful now we just have to + + + align:start position:0% +pi okay wonderful now we just have to +compute this right I mean we've got it + + align:start position:0% +compute this right I mean we've got it + + + align:start position:0% +compute this right I mean we've got it +we've got our flux is this triple + + align:start position:0% +we've got our flux is this triple + + + align:start position:0% +we've got our flux is this triple +integral so let's compute it let's let's + + align:start position:0% +integral so let's compute it let's let's + + + align:start position:0% +integral so let's compute it let's let's +walk over to this little bit of empty + + align:start position:0% +walk over to this little bit of empty + + + align:start position:0% +walk over to this little bit of empty +board space so okay so we have an + + align:start position:0% +board space so okay so we have an + + + align:start position:0% +board space so okay so we have an +iterated integral so we do it let's do + + align:start position:0% +iterated integral so we do it let's do + + + align:start position:0% +iterated integral so we do it let's do +it so the inner + + align:start position:0% +it so the inner + + + align:start position:0% +it so the inner +integral is the integral from0 to H of 2 + + align:start position:0% +integral is the integral from0 to H of 2 + + + align:start position:0% +integral is the integral from0 to H of 2 +ZR DZ well that's not that bad that's + + align:start position:0% +ZR DZ well that's not that bad that's + + + align:start position:0% +ZR DZ well that's not that bad that's +equal to R is a constant so it's equal + + align:start position:0% +equal to R is a constant so it's equal + + + align:start position:0% +equal to R is a constant so it's equal +to RZ squared as Z goes between zero and + + align:start position:0% +to RZ squared as Z goes between zero and + + + align:start position:0% +to RZ squared as Z goes between zero and +H so this is a z go you know was DZ so Z + + align:start position:0% +H so this is a z go you know was DZ so Z + + + align:start position:0% +H so this is a z go you know was DZ so Z +is going from Zer to H so this is okay + + align:start position:0% +is going from Zer to H so this is okay + + + align:start position:0% +is going from Zer to H so this is okay +we plug in and we just get h^2 R minus 0 + + align:start position:0% +we plug in and we just get h^2 R minus 0 + + + align:start position:0% +we plug in and we just get h^2 R minus 0 +so just h^2 R okay so now let's do the + + align:start position:0% +so just h^2 R okay so now let's do the + + + align:start position:0% +so just h^2 R okay so now let's do the +middle + + align:start position:0% +middle + + + align:start position:0% +middle +integral so the middle integral is the + + align:start position:0% +integral so the middle integral is the + + + align:start position:0% +integral so the middle integral is the +integral from zero to Big R D little r + + align:start position:0% +integral from zero to Big R D little r + + + align:start position:0% +integral from zero to Big R D little r +of the inner integral so this is the + + align:start position:0% +of the inner integral so this is the + + + align:start position:0% +of the inner integral so this is the +integral from zero to Big R of the inner + + align:start position:0% +integral from zero to Big R of the inner + + + align:start position:0% +integral from zero to Big R of the inner +integral which was h^2 little r d little + + align:start position:0% +integral which was h^2 little r d little + + + align:start position:0% +integral which was h^2 little r d little +r okay and that's not that bad either so + + align:start position:0% +r okay and that's not that bad either so + + + align:start position:0% +r okay and that's not that bad either so +H is just a constant so this is equal to + + align:start position:0% +H is just a constant so this is equal to + + + align:start position:0% +H is just a constant so this is equal to + + align:start position:0% + + + align:start position:0% +H2 R + + align:start position:0% +H2 R + + + align:start position:0% +H2 R +2 from R = 0 to Big R and so that's 12 + + align:start position:0% +2 from R = 0 to Big R and so that's 12 + + + align:start position:0% +2 from R = 0 to Big R and so that's 12 +h^2 Big R 2 that's the middle integral + + align:start position:0% +h^2 Big R 2 that's the middle integral + + + align:start position:0% +h^2 Big R 2 that's the middle integral +so the outer + + align:start position:0% +so the outer + + + align:start position:0% +so the outer +one now okay so let's go back and look + + align:start position:0% +one now okay so let's go back and look + + + align:start position:0% +one now okay so let's go back and look +so we're doing D Theta as Theta goes + + align:start position:0% +so we're doing D Theta as Theta goes + + + align:start position:0% +so we're doing D Theta as Theta goes +from 0 to 2 pi of whatever the middle + + align:start position:0% +from 0 to 2 pi of whatever the middle + + + align:start position:0% +from 0 to 2 pi of whatever the middle +integral was so it's the integral from + + align:start position:0% +integral was so it's the integral from + + + align:start position:0% +integral was so it's the integral from +from 0 to 2 pi of whatever the value of + + align:start position:0% +from 0 to 2 pi of whatever the value of + + + align:start position:0% +from 0 to 2 pi of whatever the value of +the middle integral was so this is 12 h² + + align:start position:0% +the middle integral was so this is 12 h² + + + align:start position:0% +the middle integral was so this is 12 h² +Big R 2 D Theta and this is all just + + align:start position:0% +Big R 2 D Theta and this is all just + + + align:start position:0% +Big R 2 D Theta and this is all just +constant with respect to Theta so that's + + align:start position:0% +constant with respect to Theta so that's + + + align:start position:0% +constant with respect to Theta so that's +going to be just pi h^2 r 2 you you know + + align:start position:0% +going to be just pi h^2 r 2 you you know + + + align:start position:0% +going to be just pi h^2 r 2 you you know +just multiplying it by 2 pi all right so + + align:start position:0% +just multiplying it by 2 pi all right so + + + align:start position:0% +just multiplying it by 2 pi all right so +pi h^2 r 2 so those our final answer + + align:start position:0% +pi h^2 r 2 so those our final answer + + + align:start position:0% +pi h^2 r 2 so those our final answer +let's just quickly recap what we did we + + align:start position:0% +let's just quickly recap what we did we + + + align:start position:0% +let's just quickly recap what we did we +had to compute the flux + + align:start position:0% +had to compute the flux + + + align:start position:0% +had to compute the flux +of this field F through the surface of a + + align:start position:0% +of this field F through the surface of a + + + align:start position:0% +of this field F through the surface of a +solid um with of a of a + + align:start position:0% +solid um with of a of a + + + align:start position:0% +solid um with of a of a +cylinder and so we had options we could + + align:start position:0% +cylinder and so we had options we could + + + align:start position:0% +cylinder and so we had options we could +do it directly by trying to compute the + + align:start position:0% +do it directly by trying to compute the + + + align:start position:0% +do it directly by trying to compute the +surface integrals but in this case life + + align:start position:0% +surface integrals but in this case life + + + align:start position:0% +surface integrals but in this case life +was a lot easier if we applied the + + align:start position:0% +was a lot easier if we applied the + + + align:start position:0% +was a lot easier if we applied the +Divergence Theorem so the Divergence + + align:start position:0% +Divergence Theorem so the Divergence + + + align:start position:0% +Divergence Theorem so the Divergence +Theorem says that that flux which is + + align:start position:0% +Theorem says that that flux which is + + + align:start position:0% +Theorem says that that flux which is +equal to this surface integral can also + + align:start position:0% +equal to this surface integral can also + + + align:start position:0% +equal to this surface integral can also +be written as the triple integral over + + align:start position:0% +be written as the triple integral over + + + align:start position:0% +be written as the triple integral over +the solid region bounded by the surface + + align:start position:0% +the solid region bounded by the surface + + + align:start position:0% +the solid region bounded by the surface +of of the Divergence of the field all + + align:start position:0% +of of the Divergence of the field all + + + align:start position:0% +of of the Divergence of the field all +right and so in our case the Divergence + + align:start position:0% +right and so in our case the Divergence + + + align:start position:0% +right and so in our case the Divergence +was very nice and simple and the region + + align:start position:0% +was very nice and simple and the region + + + align:start position:0% +was very nice and simple and the region +the solid region D was relatively + + align:start position:0% +the solid region D was relatively + + + align:start position:0% +the solid region D was relatively +simpler to describe than its surface uh + + align:start position:0% +simpler to describe than its surface uh + + + align:start position:0% +simpler to describe than its surface uh +that Bounds at s um so this is why we + + align:start position:0% +that Bounds at s um so this is why we + + + align:start position:0% +that Bounds at s um so this is why we +think of the Divergence Theorem because + + align:start position:0% +think of the Divergence Theorem because + + + align:start position:0% +think of the Divergence Theorem because +the Divergence of the field is easy to + + align:start position:0% +the Divergence of the field is easy to + + + align:start position:0% +the Divergence of the field is easy to +understand and the and the and the solid + + align:start position:0% +understand and the and the and the solid + + + align:start position:0% +understand and the and the and the solid +is easier to describe than its surface + + align:start position:0% +is easier to describe than its surface + + + align:start position:0% +is easier to describe than its surface +so those are both things that make us + + align:start position:0% +so those are both things that make us + + + align:start position:0% +so those are both things that make us +think to use the Divergence Theorem for + + align:start position:0% +think to use the Divergence Theorem for + + + align:start position:0% +think to use the Divergence Theorem for +a problem like this and so okay so so + + align:start position:0% +a problem like this and so okay so so + + + align:start position:0% +a problem like this and so okay so so +then by the Divergence Theorem the flux + + align:start position:0% +then by the Divergence Theorem the flux + + + align:start position:0% +then by the Divergence Theorem the flux +is just that integral that triple + + align:start position:0% +is just that integral that triple + + + align:start position:0% +is just that integral that triple +integral and so we wrote it out here we + + align:start position:0% +integral and so we wrote it out here we + + + align:start position:0% +integral and so we wrote it out here we +were integrating over a cylinder so a + + align:start position:0% +were integrating over a cylinder so a + + + align:start position:0% +were integrating over a cylinder so a +natural thing to do is use cylindrical + + align:start position:0% +natural thing to do is use cylindrical + + + align:start position:0% +natural thing to do is use cylindrical +coordinates and then we computed the + + align:start position:0% +coordinates and then we computed the + + + align:start position:0% +coordinates and then we computed the +triple integral just like we always do + + align:start position:0% +triple integral just like we always do + + + align:start position:0% +triple integral just like we always do +you know I did it in three steps inner + + align:start position:0% +you know I did it in three steps inner + + + align:start position:0% +you know I did it in three steps inner +middle and outer you don't have to do it + + align:start position:0% +middle and outer you don't have to do it + + + align:start position:0% +middle and outer you don't have to do it +exactly this way if you don't want to + + align:start position:0% +exactly this way if you don't want to + + + align:start position:0% +exactly this way if you don't want to +but it works for me um okay and we got + + align:start position:0% +but it works for me um okay and we got + + + align:start position:0% +but it works for me um okay and we got +our final answer pi h^2 r 2 I'll stop + + align:start position:0% +our final answer pi h^2 r 2 I'll stop + + + align:start position:0% +our final answer pi h^2 r 2 I'll stop +there \ No newline at end of file diff --git a/CMbvq16z0gA.txt b/CMbvq16z0gA.txt new file mode 100644 index 0000000000000000000000000000000000000000..db20c9b99b7c5d5bbf382bb44d6604042d698ac2 --- /dev/null +++ b/CMbvq16z0gA.txt @@ -0,0 +1,2651 @@ +align:start position:0% + +welcome back to recitation in this video + + align:start position:0% +welcome back to recitation in this video + + + align:start position:0% +welcome back to recitation in this video +I'd like us to find an anti-derivative + + align:start position:0% +I'd like us to find an anti-derivative + + + align:start position:0% +I'd like us to find an anti-derivative +of the function 1 over x^2 - 8x + 1 so + + align:start position:0% +of the function 1 over x^2 - 8x + 1 so + + + align:start position:0% +of the function 1 over x^2 - 8x + 1 so +I'll give you a while to work on it and + + align:start position:0% +I'll give you a while to work on it and + + + align:start position:0% +I'll give you a while to work on it and +then I'll come back and I'll show you + + align:start position:0% +then I'll come back and I'll show you + + + align:start position:0% +then I'll come back and I'll show you +how I + + align:start position:0% + + + + align:start position:0% + +started so welcome back well what we'd + + align:start position:0% +started so welcome back well what we'd + + + align:start position:0% +started so welcome back well what we'd +like to do is find an anti-derivative to + + align:start position:0% +like to do is find an anti-derivative to + + + align:start position:0% +like to do is find an anti-derivative to +1x^2 - 8x + 1 and how we're going to do + + align:start position:0% +1x^2 - 8x + 1 and how we're going to do + + + align:start position:0% +1x^2 - 8x + 1 and how we're going to do +that is we're going to use the technique + + align:start position:0% +that is we're going to use the technique + + + align:start position:0% +that is we're going to use the technique +completing the square and I'm going to + + align:start position:0% +completing the square and I'm going to + + + align:start position:0% +completing the square and I'm going to +set up the problem I'm going to get it + + align:start position:0% +set up the problem I'm going to get it + + + align:start position:0% +set up the problem I'm going to get it +to a certain place and then I'm going to + + align:start position:0% +to a certain place and then I'm going to + + + align:start position:0% +to a certain place and then I'm going to +let you finish it and how do you know if + + align:start position:0% +let you finish it and how do you know if + + + align:start position:0% +let you finish it and how do you know if +you got the right answer well you + + align:start position:0% +you got the right answer well you + + + align:start position:0% +you got the right answer well you +actually take a derivative of your + + align:start position:0% +actually take a derivative of your + + + align:start position:0% +actually take a derivative of your +answer and see if it gives you back 1x^2 + + align:start position:0% +answer and see if it gives you back 1x^2 + + + align:start position:0% +answer and see if it gives you back 1x^2 +- 8x + 1 that's how you can check so + + align:start position:0% +- 8x + 1 that's how you can check so + + + align:start position:0% +- 8x + 1 that's how you can check so +let's start off if I want to complete + + align:start position:0% +let's start off if I want to complete + + + align:start position:0% +let's start off if I want to complete +the square let's just remind ourselves + + align:start position:0% + + + + align:start position:0% + +how to complete the square on this uh on + + align:start position:0% +how to complete the square on this uh on + + + align:start position:0% +how to complete the square on this uh on +on this + + align:start position:0% + + + + align:start position:0% + +quadratic so I'd like + + align:start position:0% + + + + align:start position:0% + +something right here that makes this a + + align:start position:0% +something right here that makes this a + + + align:start position:0% +something right here that makes this a +perfect square right well the eight here + + align:start position:0% +perfect square right well the eight here + + + align:start position:0% +perfect square right well the eight here +in the middle if I want a perfect square + + align:start position:0% +in the middle if I want a perfect square + + + align:start position:0% +in the middle if I want a perfect square +if you think about this I'm going to + + align:start position:0% +if you think about this I'm going to + + + align:start position:0% +if you think about this I'm going to +have an x minus I need a number here + + align:start position:0% +have an x minus I need a number here + + + align:start position:0% +have an x minus I need a number here +that when I multiply it by two that's + + align:start position:0% +that when I multiply it by two that's + + + align:start position:0% +that when I multiply it by two that's +where this eight comes from gives me + + align:start position:0% +where this eight comes from gives me + + + align:start position:0% +where this eight comes from gives me +eight so obviously I need this number to + + align:start position:0% +eight so obviously I need this number to + + + align:start position:0% +eight so obviously I need this number to +be a four right which puts what here + + align:start position:0% +be a four right which puts what here + + + align:start position:0% +be a four right which puts what here +puts a 16 here + + align:start position:0% +puts a 16 here + + + align:start position:0% +puts a 16 here +right so it just to double check what + + align:start position:0% +right so it just to double check what + + + align:start position:0% +right so it just to double check what +I'm looking for is a number here I I + + align:start position:0% +I'm looking for is a number here I I + + + align:start position:0% +I'm looking for is a number here I I +need a number right here that when I + + align:start position:0% +need a number right here that when I + + + align:start position:0% +need a number right here that when I +multiply by two gives me8 and then I + + align:start position:0% +multiply by two gives me8 and then I + + + align:start position:0% +multiply by two gives me8 and then I +need it to to figure out what it squares + + align:start position:0% +need it to to figure out what it squares + + + align:start position:0% +need it to to figure out what it squares +to so that number is ne4 and it squares + + align:start position:0% +to so that number is ne4 and it squares + + + align:start position:0% +to so that number is ne4 and it squares +to 16 but obviously this isn't what I + + align:start position:0% +to 16 but obviously this isn't what I + + + align:start position:0% +to 16 but obviously this isn't what I +have right I have plus one so what have + + align:start position:0% +have right I have plus one so what have + + + align:start position:0% +have right I have plus one so what have +I had to do to get from here to here + + align:start position:0% +I had to do to get from here to here + + + align:start position:0% +I had to do to get from here to here +well I had plus one and now I have plus + + align:start position:0% +well I had plus one and now I have plus + + + align:start position:0% +well I had plus one and now I have plus +16 so obviously I've added 15 so I have + + align:start position:0% +16 so obviously I've added 15 so I have + + + align:start position:0% +16 so obviously I've added 15 so I have +to subtract 15 + + align:start position:0% +to subtract 15 + + + align:start position:0% +to subtract 15 +to keep this to keep these three lines + + align:start position:0% +to keep this to keep these three lines + + + align:start position:0% +to keep this to keep these three lines +all equal to each other so to understand + + align:start position:0% +all equal to each other so to understand + + + align:start position:0% +all equal to each other so to understand +where that comes from let's just let me + + align:start position:0% +where that comes from let's just let me + + + align:start position:0% +where that comes from let's just let me +just remind you my denominator was + + align:start position:0% +just remind you my denominator was + + + align:start position:0% +just remind you my denominator was +looking like this I'd like it to have a + + align:start position:0% +looking like this I'd like it to have a + + + align:start position:0% +looking like this I'd like it to have a +perfect square and then and then + + align:start position:0% +perfect square and then and then + + + align:start position:0% +perfect square and then and then +subtract a constant or add a constant + + align:start position:0% +subtract a constant or add a constant + + + align:start position:0% +subtract a constant or add a constant +right now I have something that I I + + align:start position:0% +right now I have something that I I + + + align:start position:0% +right now I have something that I I +don't have a perfect square in here I + + align:start position:0% +don't have a perfect square in here I + + + align:start position:0% +don't have a perfect square in here I +can't I can't make this into a perfect + + align:start position:0% +can't I can't make this into a perfect + + + align:start position:0% +can't I can't make this into a perfect +square unless I add a certain amount to + + align:start position:0% +square unless I add a certain amount to + + + align:start position:0% +square unless I add a certain amount to +the constant right here so I had to add + + align:start position:0% +the constant right here so I had to add + + + align:start position:0% +the constant right here so I had to add +15 to the constant here notice 16us 15 + + align:start position:0% +15 to the constant here notice 16us 15 + + + align:start position:0% +15 to the constant here notice 16us 15 +is one that's my check also that the + + align:start position:0% +is one that's my check also that the + + + align:start position:0% +is one that's my check also that the +lines are equal and so what I've done is + + align:start position:0% +lines are equal and so what I've done is + + + align:start position:0% +lines are equal and so what I've done is +I've added 15 and subtracted 15 and then + + align:start position:0% +I've added 15 and subtracted 15 and then + + + align:start position:0% +I've added 15 and subtracted 15 and then +I put this plus 16 into here x - 4^ s is + + align:start position:0% +I put this plus 16 into here x - 4^ s is + + + align:start position:0% +I put this plus 16 into here x - 4^ s is +exactly these first three terms and then + + align:start position:0% +exactly these first three terms and then + + + align:start position:0% +exactly these first three terms and then +I keep the minus5 now you might say why + + align:start position:0% +I keep the minus5 now you might say why + + + align:start position:0% +I keep the minus5 now you might say why +and why did you do this so let's make + + align:start position:0% +and why did you do this so let's make + + + align:start position:0% +and why did you do this so let's make +sure we understand why we're completing + + align:start position:0% +sure we understand why we're completing + + + align:start position:0% +sure we understand why we're completing +the square on this if we come back I'm + + align:start position:0% +the square on this if we come back I'm + + + align:start position:0% +the square on this if we come back I'm +going to put this line in place of + + align:start position:0% +going to put this line in place of + + + align:start position:0% +going to put this line in place of +what's in the denominator there because + + align:start position:0% +what's in the denominator there because + + + align:start position:0% +what's in the denominator there because +these three things are all equal so this + + align:start position:0% +these three things are all equal so this + + + align:start position:0% +these three things are all equal so this +is actually the integral of + + align:start position:0% +is actually the integral of + + + align:start position:0% +is actually the integral of +DX over x - 4 quantity Square quantity + + align:start position:0% +DX over x - 4 quantity Square quantity + + + align:start position:0% +DX over x - 4 quantity Square quantity +squared minus + + align:start position:0% +squared minus + + + align:start position:0% +squared minus +15 now you might say Christine this + + align:start position:0% +15 now you might say Christine this + + + align:start position:0% +15 now you might say Christine this +looks no easier I don't know why you did + + align:start position:0% +looks no easier I don't know why you did + + + align:start position:0% +looks no easier I don't know why you did +this but it actually is one of our + + align:start position:0% +this but it actually is one of our + + + align:start position:0% +this but it actually is one of our +favorite or least favorite depending on + + align:start position:0% +favorite or least favorite depending on + + + align:start position:0% +favorite or least favorite depending on +how you feel about it uh types of types + + align:start position:0% +how you feel about it uh types of types + + + align:start position:0% +how you feel about it uh types of types +of Tricks we use now which is the trig + + align:start position:0% +of Tricks we use now which is the trig + + + align:start position:0% +of Tricks we use now which is the trig +substitution so some people love this + + align:start position:0% +substitution so some people love this + + + align:start position:0% +substitution so some people love this +because they just have to memorize a + + align:start position:0% +because they just have to memorize a + + + align:start position:0% +because they just have to memorize a +little formula and some people love it + + align:start position:0% +little formula and some people love it + + + align:start position:0% +little formula and some people love it +because they can draw a triangle and + + align:start position:0% +because they can draw a triangle and + + + align:start position:0% +because they can draw a triangle and +understand what they choose um I'm going + + align:start position:0% +understand what they choose um I'm going + + + align:start position:0% +understand what they choose um I'm going +to show you remind you what the formula + + align:start position:0% +to show you remind you what the formula + + + align:start position:0% +to show you remind you what the formula +was you saw in class uh I believe + + align:start position:0% +was you saw in class uh I believe + + + align:start position:0% +was you saw in class uh I believe +Professor Jaron said something like this + + align:start position:0% +Professor Jaron said something like this + + + align:start position:0% +Professor Jaron said something like this +if the denominator is in the form U + + align:start position:0% +if the denominator is in the form U + + + align:start position:0% +if the denominator is in the form U +minus a^ 2 this implies that you make U + + align:start position:0% +minus a^ 2 this implies that you make U + + + align:start position:0% +minus a^ 2 this implies that you make U +equal to a secant + + align:start position:0% +equal to a secant + + + align:start position:0% +equal to a secant +Theta now he probably wrote it as X but + + align:start position:0% +Theta now he probably wrote it as X but + + + align:start position:0% +Theta now he probably wrote it as X but +I wrote it as U for a very specific + + align:start position:0% +I wrote it as U for a very specific + + + align:start position:0% +I wrote it as U for a very specific +reason + + align:start position:0% +reason + + + align:start position:0% +reason +because here I have x - 4 I have x - 4 + + align:start position:0% +because here I have x - 4 I have x - 4 + + + align:start position:0% +because here I have x - 4 I have x - 4 +Quan squared now this is where it gets a + + align:start position:0% +Quan squared now this is where it gets a + + + align:start position:0% +Quan squared now this is where it gets a +little rough right this is not a perfect + + align:start position:0% +little rough right this is not a perfect + + + align:start position:0% +little rough right this is not a perfect +square but it is the perfect square it + + align:start position:0% +square but it is the perfect square it + + + align:start position:0% +square but it is the perfect square it +is the square of the square root of 15 + + align:start position:0% +is the square of the square root of 15 + + + align:start position:0% +is the square of the square root of 15 +so I can write the denominator in the + + align:start position:0% +so I can write the denominator in the + + + align:start position:0% +so I can write the denominator in the +form something squared minus something + + align:start position:0% +form something squared minus something + + + align:start position:0% +form something squared minus something +else squared and again you might say why + + align:start position:0% +else squared and again you might say why + + + align:start position:0% +else squared and again you might say why +is this good well what we're going to be + + align:start position:0% +is this good well what we're going to be + + + align:start position:0% +is this good well what we're going to be +able to do is we're going to be able to + + align:start position:0% +able to do is we're going to be able to + + + align:start position:0% +able to do is we're going to be able to +rewrite this in terms of trigonometric + + align:start position:0% +rewrite this in terms of trigonometric + + + align:start position:0% +rewrite this in terms of trigonometric +function functions which will make it + + align:start position:0% +function functions which will make it + + + align:start position:0% +function functions which will make it +much simpler to solve so let's use what + + align:start position:0% +much simpler to solve so let's use what + + + align:start position:0% +much simpler to solve so let's use what +what Professor Jaron gave us and so what + + align:start position:0% +what Professor Jaron gave us and so what + + + align:start position:0% +what Professor Jaron gave us and so what +we see is that this is U and this is + + align:start position:0% +we see is that this is U and this is + + + align:start position:0% +we see is that this is U and this is +a right so I get uh x - 4 is equal to + + align:start position:0% +a right so I get uh x - 4 is equal to + + + align:start position:0% +a right so I get uh x - 4 is equal to +square < TK of + + align:start position:0% +square < TK of + + + align:start position:0% +square < TK of +15 secant Theta now you might not like + + align:start position:0% +15 secant Theta now you might not like + + + align:start position:0% +15 secant Theta now you might not like +the square root of 15 but it's just + + align:start position:0% +the square root of 15 but it's just + + + align:start position:0% +the square root of 15 but it's just +hanging out is not causing any problems + + align:start position:0% +hanging out is not causing any problems + + + align:start position:0% +hanging out is not causing any problems +it's just a number there so we'll keep + + align:start position:0% +it's just a number there so we'll keep + + + align:start position:0% +it's just a number there so we'll keep +it a square root of 15 so you don't have + + align:start position:0% +it a square root of 15 so you don't have + + + align:start position:0% +it a square root of 15 so you don't have +to worry about it now what's the point + + align:start position:0% +to worry about it now what's the point + + + align:start position:0% +to worry about it now what's the point +again let me just remind you the object + + align:start position:0% +again let me just remind you the object + + + align:start position:0% +again let me just remind you the object +is to get this in terms of the trig + + align:start position:0% +is to get this in terms of the trig + + + align:start position:0% +is to get this in terms of the trig +functions so we should anticipate that + + align:start position:0% +functions so we should anticipate that + + + align:start position:0% +functions so we should anticipate that +probably we'll have some some tangent + + align:start position:0% +probably we'll have some some tangent + + + align:start position:0% +probably we'll have some some tangent +functions to go with this and there are + + align:start position:0% +functions to go with this and there are + + + align:start position:0% +functions to go with this and there are +two reasons to to think that the first + + align:start position:0% +two reasons to to think that the first + + + align:start position:0% +two reasons to to think that the first +reason to think that is at some point I + + align:start position:0% +reason to think that is at some point I + + + align:start position:0% +reason to think that is at some point I +have to find DX well the derivative of + + align:start position:0% +have to find DX well the derivative of + + + align:start position:0% +have to find DX well the derivative of +secant involves secant and tangent right + + align:start position:0% +secant involves secant and tangent right + + + align:start position:0% +secant involves secant and tangent right +so that's going to pull in a tangent + + align:start position:0% +so that's going to pull in a tangent + + + align:start position:0% +so that's going to pull in a tangent +function somewhere I'm also going to + + align:start position:0% +function somewhere I'm also going to + + + align:start position:0% +function somewhere I'm also going to +have a tangent function show up + + align:start position:0% +have a tangent function show up + + + align:start position:0% +have a tangent function show up +somewhere else and where that's going to + + align:start position:0% +somewhere else and where that's going to + + + align:start position:0% +somewhere else and where that's going to +be is coming from this denominator this + + align:start position:0% +be is coming from this denominator this + + + align:start position:0% +be is coming from this denominator this +expression in the denominator because + + align:start position:0% +expression in the denominator because + + + align:start position:0% +expression in the denominator because +there's a certain trig identity that we + + align:start position:0% +there's a certain trig identity that we + + + align:start position:0% +there's a certain trig identity that we +we should have memorized but I'll just + + align:start position:0% +we should have memorized but I'll just + + + align:start position:0% +we should have memorized but I'll just +remind you I'll write it here and put a + + align:start position:0% +remind you I'll write it here and put a + + + align:start position:0% +remind you I'll write it here and put a +star next to it it's 1 + tangent s thet + + align:start position:0% +star next to it it's 1 + tangent s thet + + + align:start position:0% +star next to it it's 1 + tangent s thet +is equal to secant squ + + align:start position:0% +is equal to secant squ + + + align:start position:0% +is equal to secant squ +thet so this is a I'll even put a star + + align:start position:0% +thet so this is a I'll even put a star + + + align:start position:0% +thet so this is a I'll even put a star +on the other side so we should really + + align:start position:0% +on the other side so we should really + + + align:start position:0% +on the other side so we should really +remember this now where does it come + + align:start position:0% +remember this now where does it come + + + align:start position:0% +remember this now where does it come +from comes from the cosine squ theta + + align:start position:0% +from comes from the cosine squ theta + + + align:start position:0% +from comes from the cosine squ theta +plus sin squ theta equals one identity + + align:start position:0% +plus sin squ theta equals one identity + + + align:start position:0% +plus sin squ theta equals one identity +you can divide everything by cosine squ + + align:start position:0% +you can divide everything by cosine squ + + + align:start position:0% +you can divide everything by cosine squ +thet and get this one so we have this + + align:start position:0% +thet and get this one so we have this + + + align:start position:0% +thet and get this one so we have this +identity and so if you notice we're + + align:start position:0% +identity and so if you notice we're + + + align:start position:0% +identity and so if you notice we're +going to be able to manipulate we're + + align:start position:0% +going to be able to manipulate we're + + + align:start position:0% +going to be able to manipulate we're +going to be able to manipulate this the + + align:start position:0% +going to be able to manipulate this the + + + align:start position:0% +going to be able to manipulate this the +expression right here and get the + + align:start position:0% +expression right here and get the + + + align:start position:0% +expression right here and get the +denominator to look like tangent squ + + align:start position:0% +denominator to look like tangent squ + + + align:start position:0% +denominator to look like tangent squ +Theta so let's do some of that work off + + align:start position:0% +Theta so let's do some of that work off + + + align:start position:0% +Theta so let's do some of that work off +to the right + + align:start position:0% +to the right + + + align:start position:0% +to the right +here so what did I say we needed we have + + align:start position:0% +here so what did I say we needed we have + + + align:start position:0% +here so what did I say we needed we have +this expression we need DX so let's find + + align:start position:0% +this expression we need DX so let's find + + + align:start position:0% +this expression we need DX so let's find +actually no let's find the denominator + + align:start position:0% +actually no let's find the denominator + + + align:start position:0% +actually no let's find the denominator +first because I was just talking about + + align:start position:0% +first because I was just talking about + + + align:start position:0% +first because I was just talking about +it so if I look at what x - 4^ squar is + + align:start position:0% +it so if I look at what x - 4^ squar is + + + align:start position:0% +it so if I look at what x - 4^ squar is +I'm going to substitute in this + + align:start position:0% +I'm going to substitute in this + + + align:start position:0% +I'm going to substitute in this +expression + + align:start position:0% +expression + + + align:start position:0% +expression +so x - + + align:start position:0% +so x - + + + align:start position:0% +so x - +4^ 2ar - 15 is the same as based on this + + align:start position:0% +4^ 2ar - 15 is the same as based on this + + + align:start position:0% +4^ 2ar - 15 is the same as based on this +substitution < TK 15 secant + + align:start position:0% +substitution < TK 15 secant + + + align:start position:0% +substitution < TK 15 secant +Theta squarus 15 which is 15 secant 2 + + align:start position:0% +Theta squarus 15 which is 15 secant 2 + + + align:start position:0% +Theta squarus 15 which is 15 secant 2 +Theta minus 15 which just to hammer home + + align:start position:0% +Theta minus 15 which just to hammer home + + + align:start position:0% +Theta minus 15 which just to hammer home +the point is 15 * the quantity SEC 2 + + align:start position:0% +the point is 15 * the quantity SEC 2 + + + align:start position:0% +the point is 15 * the quantity SEC 2 +thetus 1 + + align:start position:0% +thetus 1 + + + align:start position:0% +thetus 1 +okay everybody follows hopefully all + + align:start position:0% +okay everybody follows hopefully all + + + align:start position:0% +okay everybody follows hopefully all +I've done is the substitution I made and + + align:start position:0% +I've done is the substitution I made and + + + align:start position:0% +I've done is the substitution I made and +then I started expanding or I squared + + align:start position:0% +then I started expanding or I squared + + + align:start position:0% +then I started expanding or I squared +this term and I factored out the 15 and + + align:start position:0% +this term and I factored out the 15 and + + + align:start position:0% +this term and I factored out the 15 and +now let's go back to my St expression + + align:start position:0% +now let's go back to my St expression + + + align:start position:0% +now let's go back to my St expression +what is secant squ Theta minus 1 it's + + align:start position:0% +what is secant squ Theta minus 1 it's + + + align:start position:0% +what is secant squ Theta minus 1 it's +tangent Square thet so we get 15 tangent + + align:start position:0% +tangent Square thet so we get 15 tangent + + + align:start position:0% +tangent Square thet so we get 15 tangent +squ thet so that is actually what the + + align:start position:0% +squ thet so that is actually what the + + + align:start position:0% +squ thet so that is actually what the +denominator of our of our integral is + + align:start position:0% +denominator of our of our integral is + + + align:start position:0% +denominator of our of our integral is +going to be over there so I'm going to + + align:start position:0% +going to be over there so I'm going to + + + align:start position:0% +going to be over there so I'm going to +come in and and put that part actually + + align:start position:0% +come in and and put that part actually + + + align:start position:0% +come in and and put that part actually +let me even put this here too so right + + align:start position:0% +let me even put this here too so right + + + align:start position:0% +let me even put this here too so right +now our + + align:start position:0% +now our + + + align:start position:0% +now our +denominator is tangent 15 tangent SAR + + align:start position:0% +denominator is tangent 15 tangent SAR + + + align:start position:0% +denominator is tangent 15 tangent SAR +Theta so far so good but of course if I + + align:start position:0% +Theta so far so good but of course if I + + + align:start position:0% +Theta so far so good but of course if I +put a DX up here I'm in trouble because + + align:start position:0% +put a DX up here I'm in trouble because + + + align:start position:0% +put a DX up here I'm in trouble because +I have it's a function of theta now so I + + align:start position:0% +I have it's a function of theta now so I + + + align:start position:0% +I have it's a function of theta now so I +need to write this I shouldn't write in + + align:start position:0% +need to write this I shouldn't write in + + + align:start position:0% +need to write this I shouldn't write in +terms of X I need to figure out what it + + align:start position:0% +terms of X I need to figure out what it + + + align:start position:0% +terms of X I need to figure out what it +is in terms of theta and to do that we + + align:start position:0% +is in terms of theta and to do that we + + + align:start position:0% +is in terms of theta and to do that we +again use the the substitution that we + + align:start position:0% +again use the the substitution that we + + + align:start position:0% +again use the the substitution that we +made which is just above the St + + align:start position:0% +made which is just above the St + + + align:start position:0% +made which is just above the St +expression it was that x - 4al Square < + + align:start position:0% +expression it was that x - 4al Square < + + + align:start position:0% +expression it was that x - 4al Square < +TK 15 secant Theta this is going to + + align:start position:0% +TK 15 secant Theta this is going to + + + align:start position:0% +TK 15 secant Theta this is going to +allow us to find what D Theta is in + + align:start position:0% +allow us to find what D Theta is in + + + align:start position:0% +allow us to find what D Theta is in +terms of + + align:start position:0% +terms of + + + align:start position:0% +terms of +DX okay so let's do + + align:start position:0% +DX okay so let's do + + + align:start position:0% +DX okay so let's do +that so I'm not done by the way over + + align:start position:0% +that so I'm not done by the way over + + + align:start position:0% +that so I'm not done by the way over +here I'm not done I've got a little Gap + + align:start position:0% +here I'm not done I've got a little Gap + + + align:start position:0% +here I'm not done I've got a little Gap +I've got to fill in in the numerator so + + align:start position:0% +I've got to fill in in the numerator so + + + align:start position:0% +I've got to fill in in the numerator so +let's come back over here so now we have + + align:start position:0% +let's come back over here so now we have + + + align:start position:0% +let's come back over here so now we have +X x - 4 let me just write that one more + + align:start position:0% + + + + align:start position:0% + +time so we get DX is equal to square < + + align:start position:0% +time so we get DX is equal to square < + + + align:start position:0% +time so we get DX is equal to square < +TK of 15 well what's the derivative of + + align:start position:0% +TK of 15 well what's the derivative of + + + align:start position:0% +TK of 15 well what's the derivative of +secant Theta it's secant + + align:start position:0% +secant Theta it's secant + + + align:start position:0% +secant Theta it's secant +Theta tangent + + align:start position:0% +Theta tangent + + + align:start position:0% +Theta tangent +Theta D Theta so now I have all the + + align:start position:0% +Theta D Theta so now I have all the + + + align:start position:0% +Theta D Theta so now I have all the +pieces I need and I'm actually going to + + align:start position:0% +pieces I need and I'm actually going to + + + align:start position:0% +pieces I need and I'm actually going to +rewrite the whole thing over over here + + align:start position:0% +rewrite the whole thing over over here + + + align:start position:0% +rewrite the whole thing over over here +underneath so that I can work with it a + + align:start position:0% +underneath so that I can work with it a + + + align:start position:0% +underneath so that I can work with it a +little bit more so the DX is in the + + align:start position:0% +little bit more so the DX is in the + + + align:start position:0% +little bit more so the DX is in the +numerator + + align:start position:0% +numerator + + + align:start position:0% +numerator +Ator < TK + + align:start position:0% +Ator < TK + + + align:start position:0% +Ator < TK +15 secant Theta tan Theta D + + align:start position:0% +15 secant Theta tan Theta D + + + align:start position:0% +15 secant Theta tan Theta D +Theta all over + + align:start position:0% +Theta all over + + + align:start position:0% +Theta all over +15 tan^ 2 + + align:start position:0% +15 tan^ 2 + + + align:start position:0% +15 tan^ 2 +thet now this might still look a little + + align:start position:0% +thet now this might still look a little + + + align:start position:0% +thet now this might still look a little +messy but we can simplify it some + + align:start position:0% +messy but we can simplify it some + + + align:start position:0% +messy but we can simplify it some +more we divide out by one tangent we'll + + align:start position:0% +more we divide out by one tangent we'll + + + align:start position:0% +more we divide out by one tangent we'll +pull this out in front and notice what's + + align:start position:0% +pull this out in front and notice what's + + + align:start position:0% +pull this out in front and notice what's +secant secant Theta is 1/ cosine Theta + + align:start position:0% +secant secant Theta is 1/ cosine Theta + + + align:start position:0% +secant secant Theta is 1/ cosine Theta +and tangent Theta is s th cosine Theta + + align:start position:0% +and tangent Theta is s th cosine Theta + + + align:start position:0% +and tangent Theta is s th cosine Theta +so let's write that down so this + + align:start position:0% +so let's write that down so this + + + align:start position:0% +so let's write that down so this +becomes < TK 15 15 we'll just leave it + + align:start position:0% +becomes < TK 15 15 we'll just leave it + + + align:start position:0% +becomes < TK 15 15 we'll just leave it +out there it's not hurting + + align:start position:0% +out there it's not hurting + + + align:start position:0% +out there it's not hurting +anyone so we get a one over cosine + + align:start position:0% +anyone so we get a one over cosine + + + align:start position:0% +anyone so we get a one over cosine +Theta times Well tangent Theta one over + + align:start position:0% +Theta times Well tangent Theta one over + + + align:start position:0% +Theta times Well tangent Theta one over +tangent Theta is coent Theta also + + align:start position:0% +tangent Theta is coent Theta also + + + align:start position:0% +tangent Theta is coent Theta also +there's another way to think about it so + + align:start position:0% +there's another way to think about it so + + + align:start position:0% +there's another way to think about it so +it's cosine Theta over sin + + align:start position:0% + + + + align:start position:0% + +Theta D + + align:start position:0% +Theta D + + + align:start position:0% +Theta D +Theta so these divide out and I'm left + + align:start position:0% +Theta so these divide out and I'm left + + + align:start position:0% +Theta so these divide out and I'm left +with I'm taking now an anti-derivative + + align:start position:0% +with I'm taking now an anti-derivative + + + align:start position:0% +with I'm taking now an anti-derivative +of 1/ sin Theta which is cose Theta so I + + align:start position:0% +of 1/ sin Theta which is cose Theta so I + + + align:start position:0% +of 1/ sin Theta which is cose Theta so I +have to find an anti-derivative of + + align:start position:0% +have to find an anti-derivative of + + + align:start position:0% +have to find an anti-derivative of +cosecant Theta well you can find that + + align:start position:0% +cosecant Theta well you can find that + + + align:start position:0% +cosecant Theta well you can find that +with the exact same strategy you found + + align:start position:0% +with the exact same strategy you found + + + align:start position:0% +with the exact same strategy you found +or I should say that Professor jarrison + + align:start position:0% +or I should say that Professor jarrison + + + align:start position:0% +or I should say that Professor jarrison +used in class or maybe it was actually + + align:start position:0% +used in class or maybe it was actually + + + align:start position:0% +used in class or maybe it was actually +Professor Miller in in that lecture to + + align:start position:0% +Professor Miller in in that lecture to + + + align:start position:0% +Professor Miller in in that lecture to +find uh an anti-derivative of secant + + align:start position:0% +find uh an anti-derivative of secant + + + align:start position:0% +find uh an anti-derivative of secant +Theta so you can do the same kind of + + align:start position:0% +Theta so you can do the same kind of + + + align:start position:0% +Theta so you can do the same kind of +thing with cosecant Theta because they + + align:start position:0% +thing with cosecant Theta because they + + + align:start position:0% +thing with cosecant Theta because they +have the same kind of derivatives + + align:start position:0% +have the same kind of derivatives + + + align:start position:0% +have the same kind of derivatives +cosecant and cotangent have very similar + + align:start position:0% +cosecant and cotangent have very similar + + + align:start position:0% +cosecant and cotangent have very similar +looking derivatives to tangent and + + align:start position:0% +looking derivatives to tangent and + + + align:start position:0% +looking derivatives to tangent and +secant same kinds of relationships so + + align:start position:0% +secant same kinds of relationships so + + + align:start position:0% +secant same kinds of relationships so +you can actually find that + + align:start position:0% +you can actually find that + + + align:start position:0% +you can actually find that +anti-derivative so this is some constant + + align:start position:0% +anti-derivative so this is some constant + + + align:start position:0% +anti-derivative so this is some constant +we don't care + + align:start position:0% + + + + align:start position:0% + +about + + align:start position:0% +about + + + align:start position:0% +about +uh and once you find that this will be + + align:start position:0% +uh and once you find that this will be + + + align:start position:0% +uh and once you find that this will be +in terms of theta your final answer + + align:start position:0% +in terms of theta your final answer + + + align:start position:0% +in terms of theta your final answer +needs to be in terms of X but you saw + + align:start position:0% +needs to be in terms of X but you saw + + + align:start position:0% +needs to be in terms of X but you saw +how to do that actually you just need to + + align:start position:0% +how to do that actually you just need to + + + align:start position:0% +how to do that actually you just need to +make a triangle that represents the + + align:start position:0% +make a triangle that represents the + + + align:start position:0% +make a triangle that represents the +relationship between uh between X and + + align:start position:0% +relationship between uh between X and + + + align:start position:0% +relationship between uh between X and +Theta so I'll draw picture of that + + align:start position:0% +Theta so I'll draw picture of that + + + align:start position:0% +Theta so I'll draw picture of that +triangle then I'll give a little summary + + align:start position:0% +triangle then I'll give a little summary + + + align:start position:0% +triangle then I'll give a little summary +of what we did and then we'll stop so + + align:start position:0% +of what we did and then we'll stop so + + + align:start position:0% +of what we did and then we'll stop so +let me draw a picture of that triangle + + align:start position:0% +let me draw a picture of that triangle + + + align:start position:0% +let me draw a picture of that triangle +so from here all you would do is + + align:start position:0% +so from here all you would do is + + + align:start position:0% +so from here all you would do is +actually find this + + align:start position:0% +actually find this + + + align:start position:0% +actually find this +anti-derivative and then you would have + + align:start position:0% +anti-derivative and then you would have + + + align:start position:0% +anti-derivative and then you would have +to make the right kind of substitution + + align:start position:0% +to make the right kind of substitution + + + align:start position:0% +to make the right kind of substitution +in terms of theta we want to know how do + + align:start position:0% +in terms of theta we want to know how do + + + align:start position:0% +in terms of theta we want to know how do +we find that do that + + align:start position:0% +we find that do that + + + align:start position:0% +we find that do that +substitution so the triangle is going to + + align:start position:0% +substitution so the triangle is going to + + + align:start position:0% +substitution so the triangle is going to +come from the following thing we know x + + align:start position:0% +come from the following thing we know x + + + align:start position:0% +come from the following thing we know x +- 4 again is square < TK of 15 secant + + align:start position:0% +- 4 again is square < TK of 15 secant + + + align:start position:0% +- 4 again is square < TK of 15 secant +Theta so I'm going to make this Theta + + align:start position:0% +Theta so I'm going to make this Theta + + + align:start position:0% +Theta so I'm going to make this Theta +secant + + align:start position:0% +secant + + + align:start position:0% +secant +what's one cosine thet cosine is + + align:start position:0% +what's one cosine thet cosine is + + + align:start position:0% +what's one cosine thet cosine is +adjacent over hypotenuse so secant is + + align:start position:0% +adjacent over hypotenuse so secant is + + + align:start position:0% +adjacent over hypotenuse so secant is +hypotenuse over + + align:start position:0% +hypotenuse over + + + align:start position:0% +hypotenuse over +adjacent right that's the relationship + + align:start position:0% +adjacent right that's the relationship + + + align:start position:0% +adjacent right that's the relationship +so x - 4 over 15 is equal to the + + align:start position:0% +so x - 4 over 15 is equal to the + + + align:start position:0% +so x - 4 over 15 is equal to the +hypotenuse over the + + align:start position:0% +hypotenuse over the + + + align:start position:0% +hypotenuse over the +adjacent did I square root sorry square + + align:start position:0% +adjacent did I square root sorry square + + + align:start position:0% +adjacent did I square root sorry square +root so the hypotenuse is x - + + align:start position:0% +root so the hypotenuse is x - + + + align:start position:0% +root so the hypotenuse is x - +4 the adjac is square < TK of 15 and + + align:start position:0% +4 the adjac is square < TK of 15 and + + + align:start position:0% +4 the adjac is square < TK of 15 and +then now I can fill in the opposite by + + align:start position:0% +then now I can fill in the opposite by + + + align:start position:0% +then now I can fill in the opposite by +Pythagorean theorem right I just take + + align:start position:0% +Pythagorean theorem right I just take + + + align:start position:0% +Pythagorean theorem right I just take +this squared and I subtract this squared + + align:start position:0% +this squared and I subtract this squared + + + align:start position:0% +this squared and I subtract this squared +and then I take the square root so I get + + align:start position:0% +and then I take the square root so I get + + + align:start position:0% +and then I take the square root so I get +the square root of x - 4^ 2ar minus + + align:start position:0% +the square root of x - 4^ 2ar minus + + + align:start position:0% +the square root of x - 4^ 2ar minus +15 so whatever I have in terms of theta + + align:start position:0% +15 so whatever I have in terms of theta + + + align:start position:0% +15 so whatever I have in terms of theta +I just look at this triangle if I had in + + align:start position:0% +I just look at this triangle if I had in + + + align:start position:0% +I just look at this triangle if I had in +my answer sin Theta I would replace sin + + align:start position:0% +my answer sin Theta I would replace sin + + + align:start position:0% +my answer sin Theta I would replace sin +Theta by this square root divided by xus + + align:start position:0% +Theta by this square root divided by xus + + + align:start position:0% +Theta by this square root divided by xus +4 because that's what sin Theta is and + + align:start position:0% +4 because that's what sin Theta is and + + + align:start position:0% +4 because that's what sin Theta is and +so from that's how I finish this type of + + align:start position:0% +so from that's how I finish this type of + + + align:start position:0% +so from that's how I finish this type of +problem always I want to have a picture + + align:start position:0% +problem always I want to have a picture + + + align:start position:0% +problem always I want to have a picture +this triangle label a Theta use my + + align:start position:0% +this triangle label a Theta use my + + + align:start position:0% +this triangle label a Theta use my +substitution to give me what the two of + + align:start position:0% +substitution to give me what the two of + + + align:start position:0% +substitution to give me what the two of +the sides are use the Pythagorean + + align:start position:0% +the sides are use the Pythagorean + + + align:start position:0% +the sides are use the Pythagorean +theorem to get the third side so that's + + align:start position:0% +theorem to get the third side so that's + + + align:start position:0% +theorem to get the third side so that's +the strategy so let's go back and just + + align:start position:0% +the strategy so let's go back and just + + + align:start position:0% +the strategy so let's go back and just +remind ourselves where we came from + + align:start position:0% +remind ourselves where we came from + + + align:start position:0% +remind ourselves where we came from +we're going to go all the way to the + + align:start position:0% +we're going to go all the way to the + + + align:start position:0% +we're going to go all the way to the +other side this was a long long + + align:start position:0% +other side this was a long long + + + align:start position:0% +other side this was a long long +problem so what did we do in this + + align:start position:0% +problem so what did we do in this + + + align:start position:0% +problem so what did we do in this +problem I wanted us to find an + + align:start position:0% +problem I wanted us to find an + + + align:start position:0% +problem I wanted us to find an +anti-derivative of something and right + + align:start position:0% +anti-derivative of something and right + + + align:start position:0% +anti-derivative of something and right +away we can't use uh we can't use + + align:start position:0% +away we can't use uh we can't use + + + align:start position:0% +away we can't use uh we can't use +partial fractions because we can't + + align:start position:0% +partial fractions because we can't + + + align:start position:0% +partial fractions because we can't +factor out an X here so I'm forced to + + align:start position:0% +factor out an X here so I'm forced to + + + align:start position:0% +factor out an X here so I'm forced to +use completing the square so I completed + + align:start position:0% +use completing the square so I completed + + + align:start position:0% +use completing the square so I completed +the square first that was a little + + align:start position:0% +the square first that was a little + + + align:start position:0% +the square first that was a little +algebra that I had to do first then once + + align:start position:0% +algebra that I had to do first then once + + + align:start position:0% +algebra that I had to do first then once +I have that little bit of Algebra I get + + align:start position:0% +I have that little bit of Algebra I get + + + align:start position:0% +I have that little bit of Algebra I get +into a situation where I'm set up for a + + align:start position:0% +into a situation where I'm set up for a + + + align:start position:0% +into a situation where I'm set up for a +trig + + align:start position:0% +trig + + + align:start position:0% +trig +substitution so then I had to start off + + align:start position:0% +substitution so then I had to start off + + + align:start position:0% +substitution so then I had to start off +and do some trig substituting and the + + align:start position:0% +and do some trig substituting and the + + + align:start position:0% +and do some trig substituting and the +things you have to do to make a trig + + align:start position:0% +things you have to do to make a trig + + + align:start position:0% +things you have to do to make a trig +substitution work are pick the pick the + + align:start position:0% +substitution work are pick the pick the + + + align:start position:0% +substitution work are pick the pick the +right substitution that makes sense + + align:start position:0% +right substitution that makes sense + + + align:start position:0% +right substitution that makes sense +which you were given that in class you + + align:start position:0% +which you were given that in class you + + + align:start position:0% +which you were given that in class you +can also figure it out from a a triangle + + align:start position:0% +can also figure it out from a a triangle + + + align:start position:0% +can also figure it out from a a triangle +picture if you wanted to and then you + + align:start position:0% +picture if you wanted to and then you + + + align:start position:0% +picture if you wanted to and then you +have to make sure you substitute not + + align:start position:0% +have to make sure you substitute not + + + align:start position:0% +have to make sure you substitute not +just for the the expression the function + + align:start position:0% +just for the the expression the function + + + align:start position:0% +just for the the expression the function +of X but also the DX so we did all that + + align:start position:0% +of X but also the DX so we did all that + + + align:start position:0% +of X but also the DX so we did all that +and then we came over further further + + align:start position:0% +and then we came over further further + + + align:start position:0% +and then we came over further further +further further further here and we had + + align:start position:0% +further further further here and we had + + + align:start position:0% +further further further here and we had +everything in terms of theta so then we + + align:start position:0% +everything in terms of theta so then we + + + align:start position:0% +everything in terms of theta so then we +had to look at the we had all these + + align:start position:0% +had to look at the we had all these + + + align:start position:0% +had to look at the we had all these +trigonometric functions of theta we + + align:start position:0% +trigonometric functions of theta we + + + align:start position:0% +trigonometric functions of theta we +simplified that as far as we could we + + align:start position:0% +simplified that as far as we could we + + + align:start position:0% +simplified that as far as we could we +got one we could find then we finally we + + align:start position:0% +got one we could find then we finally we + + + align:start position:0% +got one we could find then we finally we +take the anti-derivative there and then + + align:start position:0% +take the anti-derivative there and then + + + align:start position:0% +take the anti-derivative there and then +in the very end we're going to + + align:start position:0% +in the very end we're going to + + + align:start position:0% +in the very end we're going to +substitute in fora using the triangle + + align:start position:0% +substitute in fora using the triangle + + + align:start position:0% +substitute in fora using the triangle +we've drawn up + + align:start position:0% +we've drawn up + + + align:start position:0% +we've drawn up +here so I think that's where I'm going + + align:start position:0% +here so I think that's where I'm going + + + align:start position:0% +here so I think that's where I'm going +to stop this one also I ran out of board + + align:start position:0% +to stop this one also I ran out of board + + + align:start position:0% +to stop this one also I ran out of board +space so I have to stop \ No newline at end of file diff --git a/CR-eOhdxbes.txt b/CR-eOhdxbes.txt new file mode 100644 index 0000000000000000000000000000000000000000..b9751cabf504b2991459de48b7879d26c33ec96d --- /dev/null +++ b/CR-eOhdxbes.txt @@ -0,0 +1,2219 @@ +align:start position:0% + +superposition is uh + + align:start position:0% +superposition is uh + + + align:start position:0% +superposition is uh +very unusual and very interesting now + + align:start position:0% +very unusual and very interesting now + + + align:start position:0% +very unusual and very interesting now +we've said about + + align:start position:0% + + + + align:start position:0% + +superposition that In classical physics + + align:start position:0% +superposition that In classical physics + + + align:start position:0% +superposition that In classical physics +when we talk about superposition we have + + align:start position:0% +when we talk about superposition we have + + + align:start position:0% +when we talk about superposition we have +electric fields and you add the electric + + align:start position:0% +electric fields and you add the electric + + + align:start position:0% +electric fields and you add the electric +fields and the total electric field is + + align:start position:0% +fields and the total electric field is + + + align:start position:0% +fields and the total electric field is +the sum of electric fields and it's an + + align:start position:0% +the sum of electric fields and it's an + + + align:start position:0% +the sum of electric fields and it's an +electric field and there's nothing + + align:start position:0% +electric field and there's nothing + + + align:start position:0% +electric field and there's nothing +strange about it the nature of + + align:start position:0% +strange about it the nature of + + + align:start position:0% +strange about it the nature of +superposition in quantum mechanics is + + align:start position:0% +superposition in quantum mechanics is + + + align:start position:0% +superposition in quantum mechanics is +very strange + + align:start position:0% + + + + align:start position:0% + +so of + + align:start position:0% + + + + align:start position:0% + +superposition I will illustrate it in a + + align:start position:0% +superposition I will illustrate it in a + + + align:start position:0% +superposition I will illustrate it in a +couple of different ways one way is with + + align:start position:0% +couple of different ways one way is with + + + align:start position:0% +couple of different ways one way is with +a device that we will get accustomed to + + align:start position:0% +a device that we will get accustomed to + + + align:start position:0% +a device that we will get accustomed to +it it's called The M + + align:start position:0% + + + + align:start position:0% + +Zender Zender + + align:start position:0% + + + + align:start position:0% + +interferometer which is a + + align:start position:0% + + + + align:start position:0% + +device with a beam + + align:start position:0% +device with a beam + + + align:start position:0% +device with a beam +splitter in here you send in a beam of + + align:start position:0% +splitter in here you send in a beam of + + + align:start position:0% +splitter in here you send in a beam of +light + + align:start position:0% + + + + align:start position:0% + +input beam + + align:start position:0% +input beam + + + align:start position:0% +input beam +splitter and then the light inde half of + + align:start position:0% +splitter and then the light inde half of + + + align:start position:0% +splitter and then the light inde half of +it gets reflected half of it gets + + align:start position:0% + + + + align:start position:0% + +transmitted then you put a mirror + + align:start position:0% + + + + align:start position:0% + +here mirror one you put a mirror two + + align:start position:0% +here mirror one you put a mirror two + + + align:start position:0% +here mirror one you put a mirror two +here and this gets + + align:start position:0% +here and this gets + + + align:start position:0% +here and this gets +recombined into another beam + + align:start position:0% + + + + align:start position:0% + +splitter and then you know if there + + align:start position:0% +splitter and then you know if there + + + align:start position:0% +splitter and then you know if there +would be just a light going in here + + align:start position:0% +would be just a light going in here + + + align:start position:0% +would be just a light going in here +there would be two things going out + + align:start position:0% +there would be two things going out + + + align:start position:0% +there would be two things going out +there's another one coming from the bot + + align:start position:0% +there's another one coming from the bot + + + align:start position:0% +there's another one coming from the bot +botom there will be two there will be + + align:start position:0% +botom there will be two there will be + + + align:start position:0% +botom there will be two there will be +interference so you put a detector d0 + + align:start position:0% +interference so you put a detector d0 + + + align:start position:0% +interference so you put a detector d0 +here and a detector D1 + + align:start position:0% +here and a detector D1 + + + align:start position:0% +here and a detector D1 +here to detect the light so that's um + + align:start position:0% +here to detect the light so that's um + + + align:start position:0% +here to detect the light so that's um +the sketch of the max Zender + + align:start position:0% +the sketch of the max Zender + + + align:start position:0% +the sketch of the max Zender +interferometer beam + + align:start position:0% + + + + align:start position:0% + +Splitters and mirrors take a beam split + + align:start position:0% +Splitters and mirrors take a beam split + + + align:start position:0% +Splitters and mirrors take a beam split +the light + + align:start position:0% +the light + + + align:start position:0% +the light +go down up and then recombine it and go + + align:start position:0% +go down up and then recombine it and go + + + align:start position:0% +go down up and then recombine it and go +into + + align:start position:0% +into + + + align:start position:0% +into +detectors you can get on this is 18 uh + + align:start position:0% +detectors you can get on this is 18 uh + + + align:start position:0% +detectors you can get on this is 18 uh +was invented by these two people + + align:start position:0% +was invented by these two people + + + align:start position:0% +was invented by these two people +independently + + align:start position:0% + + + + align:start position:0% + +1890s + + align:start position:0% +1890s + + + align:start position:0% +1890s +91 to 92 + + align:start position:0% + + + + align:start position:0% + +apparently and people did this with with + + align:start position:0% +apparently and people did this with with + + + align:start position:0% +apparently and people did this with with +the light beams of light + + align:start position:0% +the light beams of light + + + align:start position:0% +the light beams of light +before they realize their + + align:start position:0% +before they realize their + + + align:start position:0% +before they realize their +photons and what happens with a beam of + + align:start position:0% +photons and what happens with a beam of + + + align:start position:0% +photons and what happens with a beam of +light it's h interesting you know comes + + align:start position:0% +light it's h interesting you know comes + + + align:start position:0% +light it's h interesting you know comes +a beam of light the beam + + align:start position:0% +a beam of light the beam + + + align:start position:0% +a beam of light the beam +splitter sends half of the light one way + + align:start position:0% +splitter sends half of the light one way + + + align:start position:0% +splitter sends half of the light one way +half of the light the other way you + + align:start position:0% +half of the light the other way you + + + align:start position:0% +half of the light the other way you +already know with quantum mechanics + + align:start position:0% +already know with quantum mechanics + + + align:start position:0% +already know with quantum mechanics +that's going to be probabilistic some + + align:start position:0% +that's going to be probabilistic some + + + align:start position:0% +that's going to be probabilistic some +photons will go up maybe some photons + + align:start position:0% +photons will go up maybe some photons + + + align:start position:0% +photons will go up maybe some photons +will go down + + align:start position:0% +will go down + + + align:start position:0% +will go down +or something more strange can + + align:start position:0% +or something more strange can + + + align:start position:0% +or something more strange can +happen if you have a + + align:start position:0% +happen if you have a + + + align:start position:0% +happen if you have a +superposition some photons may go both + + align:start position:0% +superposition some photons may go both + + + align:start position:0% +superposition some photons may go both +up and + + align:start position:0% +up and + + + align:start position:0% +up and +down so that's what can happen in + + align:start position:0% +down so that's what can happen in + + + align:start position:0% +down so that's what can happen in +quantum mechanics we can get if you send + + align:start position:0% +quantum mechanics we can get if you send + + + align:start position:0% +quantum mechanics we can get if you send +the beam classical physics it divides + + align:start position:0% +the beam classical physics it divides + + + align:start position:0% +the beam classical physics it divides +half and half and then combines and + + align:start position:0% +half and half and then combines and + + + align:start position:0% +half and half and then combines and +there's an interference effect here and + + align:start position:0% +there's an interference effect here and + + + align:start position:0% +there's an interference effect here and +we will Design This interferometer in + + align:start position:0% +we will Design This interferometer in + + + align:start position:0% +we will Design This interferometer in +such a way that sometimes we can produce + + align:start position:0% +such a way that sometimes we can produce + + + align:start position:0% +such a way that sometimes we can produce +an interference that everything goes to + + align:start position:0% +an interference that everything goes to + + + align:start position:0% +an interference that everything goes to +D or everything goes to D1 or we can + + align:start position:0% +D or everything goes to D1 or we can + + + align:start position:0% +D or everything goes to D1 or we can +produce suitable interferences that we + + align:start position:0% +produce suitable interferences that we + + + align:start position:0% +produce suitable interferences that we +can get fractions of the power going + + align:start position:0% +can get fractions of the power going + + + align:start position:0% +can get fractions of the power going +into D1 and + + align:start position:0% +into D1 and + + + align:start position:0% +into D1 and +D2 d0 and D1 so uh we can do it in + + align:start position:0% +D2 d0 and D1 so uh we can do it in + + + align:start position:0% +D2 d0 and D1 so uh we can do it in +different ways but uh we should think of + + align:start position:0% +different ways but uh we should think of + + + align:start position:0% +different ways but uh we should think of +this as a single photons single photons + + align:start position:0% +this as a single photons single photons + + + align:start position:0% +this as a single photons single photons +going one at a time you see whatever + + align:start position:0% +going one at a time you see whatever + + + align:start position:0% +going one at a time you see whatever +light you put in here experimentally the + + align:start position:0% +light you put in here experimentally the + + + align:start position:0% +light you put in here experimentally the +same frequency goes out here so what is + + align:start position:0% +same frequency goes out here so what is + + + align:start position:0% +same frequency goes out here so what is +interference you might think intuitively + + align:start position:0% +interference you might think intuitively + + + align:start position:0% +interference you might think intuitively +that + + align:start position:0% +that + + + align:start position:0% +that +interference is one Photon interfering + + align:start position:0% +interference is one Photon interfering + + + align:start position:0% +interference is one Photon interfering +with another one but it can't + + align:start position:0% +with another one but it can't + + + align:start position:0% +with another one but it can't +be if two photons would interfere in a + + align:start position:0% +be if two photons would interfere in a + + + align:start position:0% +be if two photons would interfere in a +cancelling destructive interference you + + align:start position:0% +cancelling destructive interference you + + + align:start position:0% +cancelling destructive interference you +would have a bunch of energy it goes + + align:start position:0% +would have a bunch of energy it goes + + + align:start position:0% +would have a bunch of energy it goes +into nothing it's + + align:start position:0% +into nothing it's + + + align:start position:0% +into nothing it's +impossible if they would interfere + + align:start position:0% +impossible if they would interfere + + + align:start position:0% +impossible if they would interfere +constructively you would add the + + align:start position:0% +constructively you would add the + + + align:start position:0% +constructively you would add the +electric fields and the amplitude would + + align:start position:0% +electric fields and the amplitude would + + + align:start position:0% +electric fields and the amplitude would +be four times as big because it's + + align:start position:0% +be four times as big because it's + + + align:start position:0% +be four times as big because it's +proportional to the square so but two + + align:start position:0% +proportional to the square so but two + + + align:start position:0% +proportional to the square so but two +photons are not going to go to four + + align:start position:0% +photons are not going to go to four + + + align:start position:0% +photons are not going to go to four +photons cannot conserve energy so first + + align:start position:0% +photons cannot conserve energy so first + + + align:start position:0% +photons cannot conserve energy so first +of all when you get light + + align:start position:0% +of all when you get light + + + align:start position:0% +of all when you get light +interference each photon is interfering + + align:start position:0% +interference each photon is interfering + + + align:start position:0% +interference each photon is interfering +with itself + + align:start position:0% + + + + align:start position:0% + +it's uh sounds crazy but it's the only + + align:start position:0% +it's uh sounds crazy but it's the only + + + align:start position:0% +it's uh sounds crazy but it's the only +possibility they cannot interfere with + + align:start position:0% +possibility they cannot interfere with + + + align:start position:0% +possibility they cannot interfere with +each other you can send the photons one + + align:start position:0% +each other you can send the photons one + + + align:start position:0% +each other you can send the photons one +at a + + align:start position:0% +at a + + + align:start position:0% +at a +time and therefore each + + align:start position:0% +time and therefore each + + + align:start position:0% +time and therefore each +Photon will have to be in both beams at + + align:start position:0% +Photon will have to be in both beams at + + + align:start position:0% +Photon will have to be in both beams at +the same time and then each Photon as it + + align:start position:0% +the same time and then each Photon as it + + + align:start position:0% +the same time and then each Photon as it +goes along there will be an interference + + align:start position:0% +goes along there will be an interference + + + align:start position:0% +goes along there will be an interference +effect and the photon may end up here or + + align:start position:0% +effect and the photon may end up here or + + + align:start position:0% +effect and the photon may end up here or +end up there in in a probabilistic way + + align:start position:0% +end up there in in a probabilistic way + + + align:start position:0% +end up there in in a probabilistic way +so you have an example of + + align:start position:0% + + + + align:start position:0% + +superposition per position a single + + align:start position:0% +superposition per position a single + + + align:start position:0% +superposition per position a single +Photon + + align:start position:0% +Photon + + + align:start position:0% +Photon +State a single + + align:start position:0% + + + + align:start position:0% + +photon is a super is equal to + + align:start position:0% +photon is a super is equal to + + + align:start position:0% +photon is a super is equal to +superposition of a + + align:start position:0% +superposition of a + + + align:start position:0% +superposition of a +photon in the upper beam + + align:start position:0% + + + + align:start position:0% + +and a + + align:start position:0% +and a + + + align:start position:0% +and a +photon in the lower + + align:start position:0% + + + + align:start position:0% + +beam it's like two different states a + + align:start position:0% +beam it's like two different states a + + + align:start position:0% +beam it's like two different states a +little different from here you had + + align:start position:0% +little different from here you had + + + align:start position:0% +little different from here you had +photons in two different polarization + + align:start position:0% +photons in two different polarization + + + align:start position:0% +photons in two different polarization +States superposed here you have photons + + align:start position:0% +States superposed here you have photons + + + align:start position:0% +States superposed here you have photons +in two different beams a single photon + + align:start position:0% +in two different beams a single photon + + + align:start position:0% +in two different beams a single photon +is in both beams at the same time and + + align:start position:0% +is in both beams at the same time and + + + align:start position:0% +is in both beams at the same time and +unless you have that you cannot get a + + align:start position:0% +unless you have that you cannot get a + + + align:start position:0% +unless you have that you cannot get a +superposition and an interference that + + align:start position:0% +superposition and an interference that + + + align:start position:0% +superposition and an interference that +is consistent with the experiment so + + align:start position:0% +is consistent with the experiment so + + + align:start position:0% +is consistent with the experiment so +what does that mean um for + + align:start position:0% + + + + align:start position:0% + +superpositions well it means something U + + align:start position:0% +superpositions well it means something U + + + align:start position:0% +superpositions well it means something U +that we + + align:start position:0% +that we + + + align:start position:0% +that we +can discuss and uh I can say things that + + align:start position:0% +can discuss and uh I can say things that + + + align:start position:0% +can discuss and uh I can say things that +at this moment may not make too + + align:start position:0% +at this moment may not make too + + + align:start position:0% +at this moment may not make too +much sense but uh would be a good idea + + align:start position:0% +much sense but uh would be a good idea + + + align:start position:0% +much sense but uh would be a good idea +that you think about them a little bit + + align:start position:0% +that you think about them a little bit + + + align:start position:0% +that you think about them a little bit +we Associated states with + + align:start position:0% + + + + align:start position:0% + +vectors States and vectors are the same + + align:start position:0% +vectors States and vectors are the same + + + align:start position:0% +vectors States and vectors are the same +thing and it so happens that when you + + align:start position:0% +thing and it so happens that when you + + + align:start position:0% +thing and it so happens that when you +have vectors you can write them as the + + align:start position:0% +have vectors you can write them as the + + + align:start position:0% +have vectors you can write them as the +sum of other + + align:start position:0% +sum of other + + + align:start position:0% +sum of other +vectors so the sum of these two vectors + + align:start position:0% +vectors so the sum of these two vectors + + + align:start position:0% +vectors so the sum of these two vectors +may be this Vector but you can also + + align:start position:0% +may be this Vector but you can also + + + align:start position:0% +may be this Vector but you can also +write it as the sum of these two vectors + + align:start position:0% +write it as the sum of these two vectors + + + align:start position:0% +write it as the sum of these two vectors +these two vectors add to this thing and + + align:start position:0% +these two vectors add to this thing and + + + align:start position:0% +these two vectors add to this thing and +you can write any Vector as a sum of + + align:start position:0% +you can write any Vector as a sum of + + + align:start position:0% +you can write any Vector as a sum of +different + + align:start position:0% +different + + + align:start position:0% +different +vectors and that's actually quite + + align:start position:0% +vectors and that's actually quite + + + align:start position:0% +vectors and that's actually quite +relevant you will be doing that in + + align:start position:0% +relevant you will be doing that in + + + align:start position:0% +relevant you will be doing that in +during the semester writing a state a + + align:start position:0% +during the semester writing a state a + + + align:start position:0% +during the semester writing a state a +superposition of different things and in + + align:start position:0% +superposition of different things and in + + + align:start position:0% +superposition of different things and in +that way you will understand the physics + + align:start position:0% +that way you will understand the physics + + + align:start position:0% +that way you will understand the physics +of those States so for example we can + + align:start position:0% +of those States so for example we can + + + align:start position:0% +of those States so for example we can +think of two states + + align:start position:0% +think of two states + + + align:start position:0% +think of two states +A and B and you see as I said States + + align:start position:0% +A and B and you see as I said States + + + align:start position:0% +A and B and you see as I said States +wave functions vectors we're all calling + + align:start position:0% +wave functions vectors we're all calling + + + align:start position:0% +wave functions vectors we're all calling +them the same thing if you have a + + align:start position:0% + + + + align:start position:0% + +superposition + + align:start position:0% +superposition + + + align:start position:0% +superposition +position of the states + + align:start position:0% +position of the states + + + align:start position:0% +position of the states +A and + + align:start position:0% + + + + align:start position:0% + +B what can + + align:start position:0% +B what can + + + align:start position:0% +B what can +happen all right we we'll do it the + + align:start position:0% +happen all right we we'll do it the + + + align:start position:0% +happen all right we we'll do it the +following way let's + + align:start position:0% +following way let's + + + align:start position:0% +following way let's +assume + + align:start position:0% +assume + + + align:start position:0% +assume +assume if you + + align:start position:0% +assume if you + + + align:start position:0% +assume if you +measure some property + + align:start position:0% + + + + align:start position:0% + +on + + align:start position:0% +on + + + align:start position:0% +on +a you always + + align:start position:0% +a you always + + + align:start position:0% +a you always +get value + + align:start position:0% +get value + + + align:start position:0% +get value +a so you measure something position + + align:start position:0% +a so you measure something position + + + align:start position:0% +a so you measure something position +momentum angular momentum + + align:start position:0% +momentum angular momentum + + + align:start position:0% +momentum angular momentum +spin energy + + align:start position:0% +spin energy + + + align:start position:0% +spin energy +something on + + align:start position:0% +something on + + + align:start position:0% +something on +a is a state that you always get a + + align:start position:0% +a is a state that you always get a + + + align:start position:0% +a is a state that you always get a +suppose you measure the + + align:start position:0% +suppose you measure the + + + align:start position:0% +suppose you measure the +same property on B + + align:start position:0% +same property on B + + + align:start position:0% +same property on B +you always + + align:start position:0% +you always + + + align:start position:0% +you always +get b as the + + align:start position:0% + + + + align:start position:0% + +value and + + align:start position:0% +value and + + + align:start position:0% +value and +now suppose you have a quantum + + align:start position:0% +now suppose you have a quantum + + + align:start position:0% +now suppose you have a quantum +mechanical + + align:start position:0% + + + + align:start position:0% + +State and the state is Alpha + + align:start position:0% +State and the state is Alpha + + + align:start position:0% +State and the state is Alpha +a plus beta B is a + + align:start position:0% + + + + align:start position:0% + +superos this is your + + align:start position:0% +superos this is your + + + align:start position:0% +superos this is your +state you superimpose A and B and now + + align:start position:0% +state you superimpose A and B and now + + + align:start position:0% +state you superimpose A and B and now +you + + align:start position:0% +you + + + align:start position:0% +you +measure that + + align:start position:0% +measure that + + + align:start position:0% +measure that +property that same property you could + + align:start position:0% +property that same property you could + + + align:start position:0% +property that same property you could +measure here you measure it in your + + align:start position:0% + + + + align:start position:0% + +state the the question is what will you + + align:start position:0% +state the the question is what will you + + + align:start position:0% +state the the question is what will you +get you've now superposed those states + + align:start position:0% +get you've now superposed those states + + + align:start position:0% +get you've now superposed those states +on the first state you always get a on + + align:start position:0% +on the first state you always get a on + + + align:start position:0% +on the first state you always get a on +the second state you always get B what + + align:start position:0% +the second state you always get B what + + + align:start position:0% +the second state you always get B what +do you get on the super Post State where + + align:start position:0% +do you get on the super Post State where + + + align:start position:0% +do you get on the super Post State where +Alpha and beta are + + align:start position:0% + + + + align:start position:0% + +numbers complex numbers in + + align:start position:0% + + + + align:start position:0% + +general well the most uh perhaps + + align:start position:0% +general well the most uh perhaps + + + align:start position:0% +general well the most uh perhaps +immediate guess is that you would get + + align:start position:0% +immediate guess is that you would get + + + align:start position:0% +immediate guess is that you would get +something in between maybe Alpha a plus + + align:start position:0% +something in between maybe Alpha a plus + + + align:start position:0% +something in between maybe Alpha a plus +beta b or an average or + + align:start position:0% +beta b or an average or + + + align:start position:0% +beta b or an average or +something but no that's not what happens + + align:start position:0% +something but no that's not what happens + + + align:start position:0% +something but no that's not what happens +in quantum mechanics in quantum + + align:start position:0% +in quantum mechanics in quantum + + + align:start position:0% +in quantum mechanics in quantum +mechanics it you always get a + + align:start position:0% +mechanics it you always get a + + + align:start position:0% +mechanics it you always get a +or you always get + + align:start position:0% +or you always get + + + align:start position:0% +or you always get +B so you can do the experiment many + + align:start position:0% +B so you can do the experiment many + + + align:start position:0% +B so you can do the experiment many +times and you will get a many times and + + align:start position:0% +times and you will get a many times and + + + align:start position:0% +times and you will get a many times and +you may get B many times but you never + + align:start position:0% +you may get B many times but you never + + + align:start position:0% +you may get B many times but you never +get something + + align:start position:0% +get something + + + align:start position:0% +get something +intermediate so this is very different + + align:start position:0% +intermediate so this is very different + + + align:start position:0% +intermediate so this is very different +than In classical physics if a wave has + + align:start position:0% +than In classical physics if a wave has + + + align:start position:0% +than In classical physics if a wave has +some amplitude and you add another wave + + align:start position:0% +some amplitude and you add another wave + + + align:start position:0% +some amplitude and you add another wave +of different amplitude you measure the + + align:start position:0% +of different amplitude you measure the + + + align:start position:0% +of different amplitude you measure the +energy you get something intermediate + + align:start position:0% +energy you get something intermediate + + + align:start position:0% +energy you get something intermediate +here not you make the superposition and + + align:start position:0% +here not you make the superposition and + + + align:start position:0% +here not you make the superposition and +as you measure you will either get the + + align:start position:0% +as you measure you will either get the + + + align:start position:0% +as you measure you will either get the +little a or the little B but with + + align:start position:0% +little a or the little B but with + + + align:start position:0% +little a or the little B but with +different probabilities so roughly + + align:start position:0% +different probabilities so roughly + + + align:start position:0% +different probabilities so roughly +speaking the + + align:start position:0% +speaking the + + + align:start position:0% +speaking the +probability to get little a is + + align:start position:0% +probability to get little a is + + + align:start position:0% +probability to get little a is +proportional to the number in front of + + align:start position:0% +proportional to the number in front of + + + align:start position:0% +proportional to the number in front of +here is Alpha + + align:start position:0% +here is Alpha + + + align:start position:0% +here is Alpha +squared and the + + align:start position:0% +squared and the + + + align:start position:0% +squared and the +probability to measure little B is + + align:start position:0% +probability to measure little B is + + + align:start position:0% +probability to measure little B is +proportional to Beta + + align:start position:0% +proportional to Beta + + + align:start position:0% +proportional to Beta +squar so + + align:start position:0% +squar so + + + align:start position:0% +squar so +in a Quantum + + align:start position:0% +in a Quantum + + + align:start position:0% +in a Quantum +superposition a single measurement + + align:start position:0% +superposition a single measurement + + + align:start position:0% +superposition a single measurement +doesn't yield an average result or an + + align:start position:0% +doesn't yield an average result or an + + + align:start position:0% +doesn't yield an average result or an +intermediate result it leads one or the + + align:start position:0% +intermediate result it leads one or the + + + align:start position:0% +intermediate result it leads one or the +other and this should connect with this + + align:start position:0% +other and this should connect with this + + + align:start position:0% +other and this should connect with this +um think of the photon we were talking + + align:start position:0% +um think of the photon we were talking + + + align:start position:0% +um think of the photon we were talking +before if you think of the photon that + + align:start position:0% +before if you think of the photon that + + + align:start position:0% +before if you think of the photon that +was at an angle Alpha in this way you + + align:start position:0% +was at an angle Alpha in this way you + + + align:start position:0% +was at an angle Alpha in this way you +could say that the part polarizer is + + align:start position:0% +could say that the part polarizer is + + + align:start position:0% +could say that the part polarizer is +measuring the polarization of the object + + align:start position:0% +measuring the polarization of the object + + + align:start position:0% +measuring the polarization of the object +and therefore what is the possible + + align:start position:0% +and therefore what is the possible + + + align:start position:0% +and therefore what is the possible +result it may + + align:start position:0% +result it may + + + align:start position:0% +result it may +measure the polarization and say oh if + + align:start position:0% +measure the polarization and say oh if + + + align:start position:0% +measure the polarization and say oh if +it's in the X + + align:start position:0% +it's in the X + + + align:start position:0% +it's in the X +Direction you get it right and what is + + align:start position:0% +Direction you get it right and what is + + + align:start position:0% +Direction you get it right and what is +the probability that you get it to be in + + align:start position:0% +the probability that you get it to be in + + + align:start position:0% +the probability that you get it to be in +the X direction is proportional to + + align:start position:0% +the X direction is proportional to + + + align:start position:0% +the X direction is proportional to +cosine squar Alpha the coefficient here + + align:start position:0% +cosine squar Alpha the coefficient here + + + align:start position:0% +cosine squar Alpha the coefficient here +squared so the probability that you find + + align:start position:0% +squared so the probability that you find + + + align:start position:0% +squared so the probability that you find +the photon after measuring in the X + + align:start position:0% +the photon after measuring in the X + + + align:start position:0% +the photon after measuring in the X +direction is cosine squ Alpha and the + + align:start position:0% +direction is cosine squ Alpha and the + + + align:start position:0% +direction is cosine squ Alpha and the +probability that you'll find it here is + + align:start position:0% +probability that you'll find it here is + + + align:start position:0% +probability that you'll find it here is +sin squ Alpha and after you measure you + + align:start position:0% +sin squ Alpha and after you measure you + + + align:start position:0% +sin squ Alpha and after you measure you +get this state which is to say the + + align:start position:0% +get this state which is to say the + + + align:start position:0% +get this state which is to say the +following thing the + + align:start position:0% +following thing the + + + align:start position:0% +following thing the +probability to get the value a is Alpha + + align:start position:0% +probability to get the value a is Alpha + + + align:start position:0% +probability to get the value a is Alpha +squar but if you get + + align:start position:0% +squar but if you get + + + align:start position:0% +squar but if you get +a if you get + + align:start position:0% +a if you get + + + align:start position:0% +a if you get +a the + + align:start position:0% +a the + + + align:start position:0% +a the +state be + + align:start position:0% + + + + align:start position:0% + +becomes + + align:start position:0% +becomes + + + align:start position:0% +becomes +a because this whole state of the system + + align:start position:0% +a because this whole state of the system + + + align:start position:0% +a because this whole state of the system +becomes that because successive + + align:start position:0% +becomes that because successive + + + align:start position:0% +becomes that because successive +measurements will keep giving you the + + align:start position:0% +measurements will keep giving you the + + + align:start position:0% +measurements will keep giving you the +value + + align:start position:0% +value + + + align:start position:0% +value +a if you + + align:start position:0% +a if you + + + align:start position:0% +a if you +get + + align:start position:0% +get + + + align:start position:0% +get +B the state + + align:start position:0% +B the state + + + align:start position:0% +B the state +becomes B so this is a what is called + + align:start position:0% +becomes B so this is a what is called + + + align:start position:0% +becomes B so this is a what is called +the postulate of measurement and the + + align:start position:0% +the postulate of measurement and the + + + align:start position:0% +the postulate of measurement and the +nature of superposition this is perhaps + + align:start position:0% +nature of superposition this is perhaps + + + align:start position:0% +nature of superposition this is perhaps +the most sophisticated idea we've + + align:start position:0% +the most sophisticated idea we've + + + align:start position:0% +the most sophisticated idea we've +discussed + + align:start position:0% +discussed + + + align:start position:0% +discussed +today in which in our Quantum + + align:start position:0% +today in which in our Quantum + + + align:start position:0% +today in which in our Quantum +superposition the results are not + + align:start position:0% +superposition the results are not + + + align:start position:0% +superposition the results are not +intermediate so when you want to figure + + align:start position:0% +intermediate so when you want to figure + + + align:start position:0% +intermediate so when you want to figure +out what state you have you have to + + align:start position:0% +out what state you have you have to + + + align:start position:0% +out what state you have you have to +prepare many copies of your state in + + align:start position:0% +prepare many copies of your state in + + + align:start position:0% +prepare many copies of your state in +this Quantum system and do the + + align:start position:0% +this Quantum system and do the + + + align:start position:0% +this Quantum system and do the +experiment many times because sometimes + + align:start position:0% +experiment many times because sometimes + + + align:start position:0% +experiment many times because sometimes +you'll get a sometimes you'll get B + + align:start position:0% +you'll get a sometimes you'll get B + + + align:start position:0% +you'll get a sometimes you'll get B +after you've measured many times you can + + align:start position:0% +after you've measured many times you can + + + align:start position:0% +after you've measured many times you can +assess the probabilities and reconstruct + + align:start position:0% +assess the probabilities and reconstruct + + + align:start position:0% +assess the probabilities and reconstruct +the state \ No newline at end of file diff --git a/CWlJLpAE4BI.txt b/CWlJLpAE4BI.txt new file mode 100644 index 0000000000000000000000000000000000000000..52e05e405e90b45e93d3dfe711cb777956b85dd3 --- /dev/null +++ b/CWlJLpAE4BI.txt @@ -0,0 +1,8035 @@ +align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +oh + + align:start position:0% +oh + + + align:start position:0% +oh +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +[Music] + + align:start position:0% + + + + align:start position:0% + +hi last time we had looked at an + + align:start position:0% +hi last time we had looked at an + + + align:start position:0% +hi last time we had looked at an +introduction to compensation of feedback + + align:start position:0% +introduction to compensation of feedback + + + align:start position:0% +introduction to compensation of feedback +systems in other words how do we modify + + align:start position:0% +systems in other words how do we modify + + + align:start position:0% +systems in other words how do we modify +Loop transmission of a feedback system + + align:start position:0% +Loop transmission of a feedback system + + + align:start position:0% +Loop transmission of a feedback system +in order to improve its performance + + align:start position:0% +in order to improve its performance + + + align:start position:0% +in order to improve its performance +possibly increase its speed of response + + align:start position:0% +possibly increase its speed of response + + + align:start position:0% +possibly increase its speed of response +or increase + + align:start position:0% +or increase + + + align:start position:0% +or increase +sensitivity improve the stability of the + + align:start position:0% +sensitivity improve the stability of the + + + align:start position:0% +sensitivity improve the stability of the +system those sorts of modifications that + + align:start position:0% +system those sorts of modifications that + + + align:start position:0% +system those sorts of modifications that +we very frequently want to make to to + + align:start position:0% +we very frequently want to make to to + + + align:start position:0% +we very frequently want to make to to +feedback + + align:start position:0% +feedback + + + align:start position:0% +feedback +systems the simplest kind of + + align:start position:0% +systems the simplest kind of + + + align:start position:0% +systems the simplest kind of +modification we can make is to change + + align:start position:0% +modification we can make is to change + + + align:start position:0% +modification we can make is to change +the low frequency magnitude of the loop + + align:start position:0% +the low frequency magnitude of the loop + + + align:start position:0% +the low frequency magnitude of the loop +Transmission in the notation we've been + + align:start position:0% +Transmission in the notation we've been + + + align:start position:0% +Transmission in the notation we've been +using the a fnot product and we've + + align:start position:0% +using the a fnot product and we've + + + align:start position:0% +using the a fnot product and we've +looked at how that influences the root + + align:start position:0% +looked at how that influences the root + + + align:start position:0% +looked at how that influences the root +Locust diagram for example and and last + + align:start position:0% +Locust diagram for example and and last + + + align:start position:0% +Locust diagram for example and and last +time looked at how that might improve + + align:start position:0% +time looked at how that might improve + + + align:start position:0% +time looked at how that might improve +the stability of the system today I'd + + align:start position:0% +the stability of the system today I'd + + + align:start position:0% +the stability of the system today I'd +like to look at somewhat more + + align:start position:0% +like to look at somewhat more + + + align:start position:0% +like to look at somewhat more +complicated modifications of the loop + + align:start position:0% +complicated modifications of the loop + + + align:start position:0% +complicated modifications of the loop +Transmission in particular ones that + + align:start position:0% +Transmission in particular ones that + + + align:start position:0% +Transmission in particular ones that +change the Dynamics associated with the + + align:start position:0% +change the Dynamics associated with the + + + align:start position:0% +change the Dynamics associated with the +loop + + align:start position:0% +loop + + + align:start position:0% +loop +transmission the simplest thing that we + + align:start position:0% +transmission the simplest thing that we + + + align:start position:0% +transmission the simplest thing that we +can do is to add a dominant Pole to the + + align:start position:0% +can do is to add a dominant Pole to the + + + align:start position:0% +can do is to add a dominant Pole to the +system suppose we start with A system + + align:start position:0% +system suppose we start with A system + + + align:start position:0% +system suppose we start with A system +that has a bod plot as shown here's the + + align:start position:0% +that has a bod plot as shown here's the + + + align:start position:0% +that has a bod plot as shown here's the +AF product as a function of + + align:start position:0% +AF product as a function of + + + align:start position:0% +AF product as a function of +frequency the magnitude and the angle in + + align:start position:0% +frequency the magnitude and the angle in + + + align:start position:0% +frequency the magnitude and the angle in +our usual body plot + + align:start position:0% +our usual body plot + + + align:start position:0% +our usual body plot +coordinates and as I've drawn things the + + align:start position:0% +coordinates and as I've drawn things the + + + align:start position:0% +coordinates and as I've drawn things the +system is actually + + align:start position:0% +system is actually + + + align:start position:0% +system is actually +unstable uh this is the unity magnitude + + align:start position:0% +unstable uh this is the unity magnitude + + + align:start position:0% +unstable uh this is the unity magnitude +point so this would be the crossover + + align:start position:0% +point so this would be the crossover + + + align:start position:0% +point so this would be the crossover +frequency for the system the frequency + + align:start position:0% +frequency for the system the frequency + + + align:start position:0% +frequency for the system the frequency +at which the magnitude of the AF product + + align:start position:0% +at which the magnitude of the AF product + + + align:start position:0% +at which the magnitude of the AF product +goes through unity and we notice that by + + align:start position:0% +goes through unity and we notice that by + + + align:start position:0% +goes through unity and we notice that by +that frequency the angle associated with + + align:start position:0% +that frequency the angle associated with + + + align:start position:0% +that frequency the angle associated with +the AF product has gone through minus + + align:start position:0% +the AF product has gone through minus + + + align:start position:0% +the AF product has gone through minus +180° consequently this is a system + + align:start position:0% +180° consequently this is a system + + + align:start position:0% +180° consequently this is a system +that's unstable as shown + + align:start position:0% +that's unstable as shown + + + align:start position:0% +that's unstable as shown +now suppose I'd like to modify that + + align:start position:0% +now suppose I'd like to modify that + + + align:start position:0% +now suppose I'd like to modify that +system and in fact try to increase its + + align:start position:0% +system and in fact try to increase its + + + align:start position:0% +system and in fact try to increase its +phase margin possibly to + + align:start position:0% +phase margin possibly to + + + align:start position:0% +phase margin possibly to +45° if I added one more Pole to the + + align:start position:0% +45° if I added one more Pole to the + + + align:start position:0% +45° if I added one more Pole to the +system at a sufficiently low frequency + + align:start position:0% +system at a sufficiently low frequency + + + align:start position:0% +system at a sufficiently low frequency +what I could do is get the magnitude to + + align:start position:0% +what I could do is get the magnitude to + + + align:start position:0% +what I could do is get the magnitude to +roll off and in fact get down to Unity + + align:start position:0% +roll off and in fact get down to Unity + + + align:start position:0% +roll off and in fact get down to Unity +before I + + align:start position:0% +before I + + + align:start position:0% +before I +acquired enough phase shift to cause + + align:start position:0% +acquired enough phase shift to cause + + + align:start position:0% +acquired enough phase shift to cause +instability let's see how we might do + + align:start position:0% +instability let's see how we might do + + + align:start position:0% +instability let's see how we might do +that I know that if I add a single pole + + align:start position:0% +that I know that if I add a single pole + + + align:start position:0% +that I know that if I add a single pole +well below crossover by the time I get + + align:start position:0% +well below crossover by the time I get + + + align:start position:0% +well below crossover by the time I get +out to the crossover frequency the phase + + align:start position:0% +out to the crossover frequency the phase + + + align:start position:0% +out to the crossover frequency the phase +shift associated with that pole will be + + align:start position:0% +shift associated with that pole will be + + + align:start position:0% +shift associated with that pole will be +very nearly minus + + align:start position:0% + + + + align:start position:0% + +90° suppose I look at the original uncom + + align:start position:0% +90° suppose I look at the original uncom + + + align:start position:0% +90° suppose I look at the original uncom +uncompensated bod plot and find the + + align:start position:0% +uncompensated bod plot and find the + + + align:start position:0% +uncompensated bod plot and find the +frequency where the phase shift of the + + align:start position:0% +frequency where the phase shift of the + + + align:start position:0% +frequency where the phase shift of the +original uncompensated system is minus + + align:start position:0% +original uncompensated system is minus + + + align:start position:0% +original uncompensated system is minus +45 degrees I recognize that if I added + + align:start position:0% +45 degrees I recognize that if I added + + + align:start position:0% +45 degrees I recognize that if I added +an additional 90 degrees of negative + + align:start position:0% +an additional 90 degrees of negative + + + align:start position:0% +an additional 90 degrees of negative +phase shift I'd end up with the angle at + + align:start position:0% +phase shift I'd end up with the angle at + + + align:start position:0% +phase shift I'd end up with the angle at +this frequency being minus 135° in other + + align:start position:0% +this frequency being minus 135° in other + + + align:start position:0% +this frequency being minus 135° in other +words if I could force crossover to + + align:start position:0% +words if I could force crossover to + + + align:start position:0% +words if I could force crossover to +occur at this frequency by adding a + + align:start position:0% +occur at this frequency by adding a + + + align:start position:0% +occur at this frequency by adding a +single pole to the loop transmission at + + align:start position:0% +single pole to the loop transmission at + + + align:start position:0% +single pole to the loop transmission at +a sufficiently low frequency I would end + + align:start position:0% +a sufficiently low frequency I would end + + + align:start position:0% +a sufficiently low frequency I would end +up with a system that has 45 degrees of + + align:start position:0% +up with a system that has 45 degrees of + + + align:start position:0% +up with a system that has 45 degrees of +phase margin so let's see if we can do + + align:start position:0% +phase margin so let's see if we can do + + + align:start position:0% +phase margin so let's see if we can do +that all we do assuming the physical + + align:start position:0% +that all we do assuming the physical + + + align:start position:0% +that all we do assuming the physical +constraints of the system allow that is + + align:start position:0% +constraints of the system allow that is + + + align:start position:0% +constraints of the system allow that is +to somehow add energy storage to the + + align:start position:0% +to somehow add energy storage to the + + + align:start position:0% +to somehow add energy storage to the +system + + align:start position:0% +system + + + align:start position:0% +system +and let's suppose as we indicated we'd + + align:start position:0% +and let's suppose as we indicated we'd + + + align:start position:0% +and let's suppose as we indicated we'd +like to cross over at this + + align:start position:0% +like to cross over at this + + + align:start position:0% +like to cross over at this +frequency and that tells us that we'd + + align:start position:0% +frequency and that tells us that we'd + + + align:start position:0% +frequency and that tells us that we'd +like to have a single pole roll + + align:start position:0% +like to have a single pole roll + + + align:start position:0% +like to have a single pole roll +off like so in the vicinity of crossover + + align:start position:0% +off like so in the vicinity of crossover + + + align:start position:0% +off like so in the vicinity of crossover +if I've accomplished that by adding a + + align:start position:0% +if I've accomplished that by adding a + + + align:start position:0% +if I've accomplished that by adding a +single pole at a sufficiently low + + align:start position:0% +single pole at a sufficiently low + + + align:start position:0% +single pole at a sufficiently low +frequency why we'd end up with a loop + + align:start position:0% +frequency why we'd end up with a loop + + + align:start position:0% +frequency why we'd end up with a loop +transmission magnitude that looks + + align:start position:0% +transmission magnitude that looks + + + align:start position:0% +transmission magnitude that looks +something like this after compensation + + align:start position:0% +something like this after compensation + + + align:start position:0% +something like this after compensation +out in this region we actually have to + + align:start position:0% +out in this region we actually have to + + + align:start position:0% +out in this region we actually have to +follow the original curve uh on top of + + align:start position:0% +follow the original curve uh on top of + + + align:start position:0% +follow the original curve uh on top of +the single pole roll off so possibly + + align:start position:0% +the single pole roll off so possibly + + + align:start position:0% +the single pole roll off so possibly +we'd get a a magnitude that looks + + align:start position:0% +we'd get a a magnitude that looks + + + align:start position:0% +we'd get a a magnitude that looks +something like that the influence on the + + align:start position:0% +something like that the influence on the + + + align:start position:0% +something like that the influence on the +angle associated with the AF product is + + align:start position:0% +angle associated with the AF product is + + + align:start position:0% +angle associated with the AF product is +simply to add an additional 90 de of + + align:start position:0% +simply to add an additional 90 de of + + + align:start position:0% +simply to add an additional 90 de of +phase shift 45 of it occurs at the + + align:start position:0% +phase shift 45 of it occurs at the + + + align:start position:0% +phase shift 45 of it occurs at the +location of the pole and then we ASM + + align:start position:0% +location of the pole and then we ASM + + + align:start position:0% +location of the pole and then we ASM +totically Trail off to an additional 90° + + align:start position:0% +totically Trail off to an additional 90° + + + align:start position:0% +totically Trail off to an additional 90° +of negative phase shift so the + + align:start position:0% +of negative phase shift so the + + + align:start position:0% +of negative phase shift so the +compensated angle might look something + + align:start position:0% +compensated angle might look something + + + align:start position:0% +compensated angle might look something +like + + align:start position:0% + + + + align:start position:0% + +so here we've acquired our additional 90 + + align:start position:0% +so here we've acquired our additional 90 + + + align:start position:0% +so here we've acquired our additional 90 +de of phase shift and we now go and + + align:start position:0% +de of phase shift and we now go and + + + align:start position:0% +de of phase shift and we now go and +continue parallel to the original angle + + align:start position:0% +continue parallel to the original angle + + + align:start position:0% +continue parallel to the original angle +curve but displaced by minus + + align:start position:0% +curve but displaced by minus + + + align:start position:0% +curve but displaced by minus +90° so our new angle curve might look + + align:start position:0% +90° so our new angle curve might look + + + align:start position:0% +90° so our new angle curve might look +something like that and now we've in + + align:start position:0% +something like that and now we've in + + + align:start position:0% +something like that and now we've in +fact accomplished our objective of + + align:start position:0% +fact accomplished our objective of + + + align:start position:0% +fact accomplished our objective of +achieving 45° of phase margin for the + + align:start position:0% +achieving 45° of phase margin for the + + + align:start position:0% +achieving 45° of phase margin for the +compensated + + align:start position:0% +compensated + + + align:start position:0% +compensated +system the price we've paid however is a + + align:start position:0% +system the price we've paid however is a + + + align:start position:0% +system the price we've paid however is a +very significant one in terms of the + + align:start position:0% +very significant one in terms of the + + + align:start position:0% +very significant one in terms of the +bandwidth of the resultant system + + align:start position:0% +bandwidth of the resultant system + + + align:start position:0% +bandwidth of the resultant system +originally our crossover frequency was + + align:start position:0% +originally our crossover frequency was + + + align:start position:0% +originally our crossover frequency was +out here we've made a very very major + + align:start position:0% +out here we've made a very very major + + + align:start position:0% +out here we've made a very very major +change in crossover frequency we've + + align:start position:0% +change in crossover frequency we've + + + align:start position:0% +change in crossover frequency we've +lowered crossover frequency considerably + + align:start position:0% +lowered crossover frequency considerably + + + align:start position:0% +lowered crossover frequency considerably +by putting in our dominant pole starting + + align:start position:0% +by putting in our dominant pole starting + + + align:start position:0% +by putting in our dominant pole starting +the roll off at a much lower frequency + + align:start position:0% +the roll off at a much lower frequency + + + align:start position:0% +the roll off at a much lower frequency +uh than we originally did we've also + + align:start position:0% +uh than we originally did we've also + + + align:start position:0% +uh than we originally did we've also +lost desensitivity over a very wide + + align:start position:0% +lost desensitivity over a very wide + + + align:start position:0% +lost desensitivity over a very wide +range of frequencies we notice of course + + align:start position:0% +range of frequencies we notice of course + + + align:start position:0% +range of frequencies we notice of course +here's the original magnitude curve + + align:start position:0% +here's the original magnitude curve + + + align:start position:0% +here's the original magnitude curve +we've lowered the AF product at all + + align:start position:0% +we've lowered the AF product at all + + + align:start position:0% +we've lowered the AF product at all +frequencies Beyond this frequency and so + + align:start position:0% +frequencies Beyond this frequency and so + + + align:start position:0% +frequencies Beyond this frequency and so +again compared to the original + + align:start position:0% +again compared to the original + + + align:start position:0% +again compared to the original +uncompensated system we've lost + + align:start position:0% +uncompensated system we've lost + + + align:start position:0% +uncompensated system we've lost +desensitivity and and the Shaded area is + + align:start position:0% +desensitivity and and the Shaded area is + + + align:start position:0% +desensitivity and and the Shaded area is +a measure of the amount of desensitivity + + align:start position:0% +a measure of the amount of desensitivity + + + align:start position:0% +a measure of the amount of desensitivity +we've lost as a function of + + align:start position:0% +we've lost as a function of + + + align:start position:0% +we've lost as a function of +frequency say the disadvantage of that + + align:start position:0% +frequency say the disadvantage of that + + + align:start position:0% +frequency say the disadvantage of that +sort of compensation is simply the + + align:start position:0% +sort of compensation is simply the + + + align:start position:0% +sort of compensation is simply the +greatly narrowing effect that it has on + + align:start position:0% +greatly narrowing effect that it has on + + + align:start position:0% +greatly narrowing effect that it has on +the bandwidth of the system but there's + + align:start position:0% +the bandwidth of the system but there's + + + align:start position:0% +the bandwidth of the system but there's +one important class of of systems where + + align:start position:0% +one important class of of systems where + + + align:start position:0% +one important class of of systems where +that sort of of approach is a very very + + align:start position:0% +that sort of of approach is a very very + + + align:start position:0% +that sort of of approach is a very very +good one to to + + align:start position:0% +good one to to + + + align:start position:0% +good one to to +compensation in particular suppose our + + align:start position:0% +compensation in particular suppose our + + + align:start position:0% +compensation in particular suppose our +objective is to build a regulator that + + align:start position:0% +objective is to build a regulator that + + + align:start position:0% +objective is to build a regulator that +is a system where the intent is to keep + + align:start position:0% +is a system where the intent is to keep + + + align:start position:0% +is a system where the intent is to keep +an output variable fixed this is in + + align:start position:0% +an output variable fixed this is in + + + align:start position:0% +an output variable fixed this is in +contrast to the usual following kind of + + align:start position:0% +contrast to the usual following kind of + + + align:start position:0% +contrast to the usual following kind of +feedback system where we try to command + + align:start position:0% +feedback system where we try to command + + + align:start position:0% +feedback system where we try to command +an output to follow a Time varying input + + align:start position:0% +an output to follow a Time varying input + + + align:start position:0% +an output to follow a Time varying input +and under those conditions when we're + + align:start position:0% +and under those conditions when we're + + + align:start position:0% +and under those conditions when we're +trying to track a Time varying input the + + align:start position:0% +trying to track a Time varying input the + + + align:start position:0% +trying to track a Time varying input the +bandwidth of the system is of course + + align:start position:0% +bandwidth of the system is of course + + + align:start position:0% +bandwidth of the system is of course +very important the closed loop bandwidth + + align:start position:0% +very important the closed loop bandwidth + + + align:start position:0% +very important the closed loop bandwidth +however when we're trying to get the + + align:start position:0% +however when we're trying to get the + + + align:start position:0% +however when we're trying to get the +output of a system to be time invariant + + align:start position:0% +output of a system to be time invariant + + + align:start position:0% +output of a system to be time invariant +a regulator where we want the output to + + align:start position:0% +a regulator where we want the output to + + + align:start position:0% +a regulator where we want the output to +to remain fixed in for all time adding + + align:start position:0% +to remain fixed in for all time adding + + + align:start position:0% +to remain fixed in for all time adding +energy storage to the output creating a + + align:start position:0% +energy storage to the output creating a + + + align:start position:0% +energy storage to the output creating a +dominant pole by basically adding energy + + align:start position:0% +dominant pole by basically adding energy + + + align:start position:0% +dominant pole by basically adding energy +storage to the output really improves + + align:start position:0% +storage to the output really improves + + + align:start position:0% +storage to the output really improves +the stiffness of the output if you will + + align:start position:0% +the stiffness of the output if you will + + + align:start position:0% +the stiffness of the output if you will +it improves the ability of the output to + + align:start position:0% +it improves the ability of the output to + + + align:start position:0% +it improves the ability of the output to +resist + + align:start position:0% +resist + + + align:start position:0% +resist +disturbances as an example of that + + align:start position:0% +disturbances as an example of that + + + align:start position:0% +disturbances as an example of that +consider what happens if we take an + + align:start position:0% +consider what happens if we take an + + + align:start position:0% +consider what happens if we take an +ordinary laboratory power supply and we + + align:start position:0% +ordinary laboratory power supply and we + + + align:start position:0% +ordinary laboratory power supply and we +go searching around and find the largest + + align:start position:0% +go searching around and find the largest + + + align:start position:0% +go searching around and find the largest +capacitor we can find and roll that up + + align:start position:0% +capacitor we can find and roll that up + + + align:start position:0% +capacitor we can find and roll that up +to the power supply and just clamp it + + align:start position:0% +to the power supply and just clamp it + + + align:start position:0% +to the power supply and just clamp it +onto the output terminals we may have + + align:start position:0% +onto the output terminals we may have + + + align:start position:0% +onto the output terminals we may have +some trouble starting the supply when we + + align:start position:0% +some trouble starting the supply when we + + + align:start position:0% +some trouble starting the supply when we +first turn it on it may take a while to + + align:start position:0% +first turn it on it may take a while to + + + align:start position:0% +first turn it on it may take a while to +charge up the large capacitor that we've + + align:start position:0% +charge up the large capacitor that we've + + + align:start position:0% +charge up the large capacitor that we've +added to the output of the system but + + align:start position:0% +added to the output of the system but + + + align:start position:0% +added to the output of the system but +once we finally get the capacitor + + align:start position:0% +once we finally get the capacitor + + + align:start position:0% +once we finally get the capacitor +charged we're in very good shape the + + align:start position:0% +charged we're in very good shape the + + + align:start position:0% +charged we're in very good shape the +capacitor at the output of the feedback + + align:start position:0% +capacitor at the output of the feedback + + + align:start position:0% +capacitor at the output of the feedback +system or the regulator in this case + + align:start position:0% +system or the regulator in this case + + + align:start position:0% +system or the regulator in this case +resists disturbances that come for + + align:start position:0% +resists disturbances that come for + + + align:start position:0% +resists disturbances that come for +example from changes in load current + + align:start position:0% +example from changes in load current + + + align:start position:0% +example from changes in load current +from changes in primary unregulated + + align:start position:0% +from changes in primary unregulated + + + align:start position:0% +from changes in primary unregulated +voltage and so forth and really helps + + align:start position:0% +voltage and so forth and really helps + + + align:start position:0% +voltage and so forth and really helps +improve the resistance of the system to + + align:start position:0% +improve the resistance of the system to + + + align:start position:0% +improve the resistance of the system to +those kinds of of disturbances so if our + + align:start position:0% +those kinds of of disturbances so if our + + + align:start position:0% +those kinds of of disturbances so if our +intent is to build a regulator where + + align:start position:0% +intent is to build a regulator where + + + align:start position:0% +intent is to build a regulator where +what we want to do is keep the output of + + align:start position:0% +what we want to do is keep the output of + + + align:start position:0% +what we want to do is keep the output of +the system time in variant then adding a + + align:start position:0% +the system time in variant then adding a + + + align:start position:0% +the system time in variant then adding a +dominant pole providing we put the + + align:start position:0% +dominant pole providing we put the + + + align:start position:0% +dominant pole providing we put the +energy storage associated with the pole + + align:start position:0% +energy storage associated with the pole + + + align:start position:0% +energy storage associated with the pole +at the output of the system at the + + align:start position:0% +at the output of the system at the + + + align:start position:0% +at the output of the system at the +variable where we're trying that we're + + align:start position:0% +variable where we're trying that we're + + + align:start position:0% +variable where we're trying that we're +trying to keep constant why we get an + + align:start position:0% +trying to keep constant why we get an + + + align:start position:0% +trying to keep constant why we get an +improvement in + + align:start position:0% +improvement in + + + align:start position:0% +improvement in +performance I do an example in the book + + align:start position:0% +performance I do an example in the book + + + align:start position:0% +performance I do an example in the book +of an electronic regulator and show how + + align:start position:0% +of an electronic regulator and show how + + + align:start position:0% +of an electronic regulator and show how +that works what I'd like to talk about + + align:start position:0% +that works what I'd like to talk about + + + align:start position:0% +that works what I'd like to talk about +here as an alternative is a speed + + align:start position:0% +here as an alternative is a speed + + + align:start position:0% +here as an alternative is a speed +control system so let's look at that a + + align:start position:0% +control system so let's look at that a + + + align:start position:0% +control system so let's look at that a +little + + align:start position:0% +little + + + align:start position:0% +little +bit here we have a system where we + + align:start position:0% +bit here we have a system where we + + + align:start position:0% +bit here we have a system where we +assume that what we're trying to do is + + align:start position:0% +assume that what we're trying to do is + + + align:start position:0% +assume that what we're trying to do is +keep an output velocity which I indicate + + align:start position:0% +keep an output velocity which I indicate + + + align:start position:0% +keep an output velocity which I indicate +as aega response fixed we might command + + align:start position:0% +as aega response fixed we might command + + + align:start position:0% +as aega response fixed we might command +some + + align:start position:0% +some + + + align:start position:0% +some +speed but we assume that this command is + + align:start position:0% +speed but we assume that this command is + + + align:start position:0% +speed but we assume that this command is +is really a fixed quantity or at most + + align:start position:0% +is really a fixed quantity or at most + + + align:start position:0% +is really a fixed quantity or at most +incred incredibly slowly time varying so + + align:start position:0% +incred incredibly slowly time varying so + + + align:start position:0% +incred incredibly slowly time varying so +we put in a command and our hope is that + + align:start position:0% +we put in a command and our hope is that + + + align:start position:0% +we put in a command and our hope is that +eventually the system reaches a speed + + align:start position:0% +eventually the system reaches a speed + + + align:start position:0% +eventually the system reaches a speed +that's about equal to that command in + + align:start position:0% +that's about equal to that command in + + + align:start position:0% +that's about equal to that command in +the system I've shown notice that we + + align:start position:0% +the system I've shown notice that we + + + align:start position:0% +the system I've shown notice that we +have Unity feedback in this system and + + align:start position:0% +have Unity feedback in this system and + + + align:start position:0% +have Unity feedback in this system and +from then on we're supposed to keep or + + align:start position:0% +from then on we're supposed to keep or + + + align:start position:0% +from then on we're supposed to keep or +the intent of the feedback system is to + + align:start position:0% +the intent of the feedback system is to + + + align:start position:0% +the intent of the feedback system is to +keep the output velocity fixed and the + + align:start position:0% +keep the output velocity fixed and the + + + align:start position:0% +keep the output velocity fixed and the +disturbances that we'll consider are + + align:start position:0% +disturbances that we'll consider are + + + align:start position:0% +disturbances that we'll consider are +torque disturbances that are applied to + + align:start position:0% +torque disturbances that are applied to + + + align:start position:0% +torque disturbances that are applied to +the mechanical system our system + + align:start position:0% +the mechanical system our system + + + align:start position:0% +the mechanical system our system +consists of an amplifier driving a motor + + align:start position:0% +consists of an amplifier driving a motor + + + align:start position:0% +consists of an amplifier driving a motor +we measure the velocity of the motor + + align:start position:0% +we measure the velocity of the motor + + + align:start position:0% +we measure the velocity of the motor +with some sort of a device they're + + align:start position:0% +with some sort of a device they're + + + align:start position:0% +with some sort of a device they're +called tachometers which allows us to + + align:start position:0% +called tachometers which allows us to + + + align:start position:0% +called tachometers which allows us to +feed back information concerning the + + align:start position:0% +feed back information concerning the + + + align:start position:0% +feed back information concerning the +output velocity We compare that with a + + align:start position:0% +output velocity We compare that with a + + + align:start position:0% +output velocity We compare that with a +set point or commanded velocity amplify + + align:start position:0% +set point or commanded velocity amplify + + + align:start position:0% +set point or commanded velocity amplify +the difference and of course apply that + + align:start position:0% +the difference and of course apply that + + + align:start position:0% +the difference and of course apply that +voltage to the motor we assume that the + + align:start position:0% +voltage to the motor we assume that the + + + align:start position:0% +voltage to the motor we assume that the +total inertia of the load this includes + + align:start position:0% +total inertia of the load this includes + + + align:start position:0% +total inertia of the load this includes +the Armature inertia of the motor uh any + + align:start position:0% +the Armature inertia of the motor uh any + + + align:start position:0% +the Armature inertia of the motor uh any +rotating load that we have we assume + + align:start position:0% +rotating load that we have we assume + + + align:start position:0% +rotating load that we have we assume +that the that total inertia is J and as + + align:start position:0% +that the that total inertia is J and as + + + align:start position:0% +that the that total inertia is J and as +I say the objective of the system is to + + align:start position:0% +I say the objective of the system is to + + + align:start position:0% +I say the objective of the system is to +keep this velocity fixed as we apply + + align:start position:0% +keep this velocity fixed as we apply + + + align:start position:0% +keep this velocity fixed as we apply +torque disturbances to the + + align:start position:0% +torque disturbances to the + + + align:start position:0% +torque disturbances to the +system we have to start out modeling the + + align:start position:0% +system we have to start out modeling the + + + align:start position:0% +system we have to start out modeling the +motor and there's a large and important + + align:start position:0% +motor and there's a large and important + + + align:start position:0% +motor and there's a large and important +class of Motors that are very well + + align:start position:0% +class of Motors that are very well + + + align:start position:0% +class of Motors that are very well +modeled by this simple a model if we + + align:start position:0% +modeled by this simple a model if we + + + align:start position:0% +modeled by this simple a model if we +have a motor that has a fixed magnetic + + align:start position:0% +have a motor that has a fixed magnetic + + + align:start position:0% +have a motor that has a fixed magnetic +field either as a consequence of a + + align:start position:0% +field either as a consequence of a + + + align:start position:0% +field either as a consequence of a +winding excited by fixed current + + align:start position:0% +winding excited by fixed current + + + align:start position:0% +winding excited by fixed current +or as a consequence of a permanent + + align:start position:0% +or as a consequence of a permanent + + + align:start position:0% +or as a consequence of a permanent +magnet why we're very often able to + + align:start position:0% +magnet why we're very often able to + + + align:start position:0% +magnet why we're very often able to +model that kind of a motor in this way + + align:start position:0% +model that kind of a motor in this way + + + align:start position:0% +model that kind of a motor in this way +here we have a resistance which is the + + align:start position:0% +here we have a resistance which is the + + + align:start position:0% +here we have a resistance which is the +Armature resistance of the motor and + + align:start position:0% +Armature resistance of the motor and + + + align:start position:0% +Armature resistance of the motor and +there's a back voltage generator whose + + align:start position:0% +there's a back voltage generator whose + + + align:start position:0% +there's a back voltage generator whose +voltage is some constant that has to do + + align:start position:0% +voltage is some constant that has to do + + + align:start position:0% +voltage is some constant that has to do +with the way the motor is constructed + + align:start position:0% +with the way the motor is constructed + + + align:start position:0% +with the way the motor is constructed +times the mechanical shaft velocity of + + align:start position:0% +times the mechanical shaft velocity of + + + align:start position:0% +times the mechanical shaft velocity of +the + + align:start position:0% +the + + + align:start position:0% +the +motor at the same time the torque that + + align:start position:0% +motor at the same time the torque that + + + align:start position:0% +motor at the same time the torque that +the motor supplies is simply equal to + + align:start position:0% +the motor supplies is simply equal to + + + align:start position:0% +the motor supplies is simply equal to +the Armature current multiplied by a + + align:start position:0% +the Armature current multiplied by a + + + align:start position:0% +the Armature current multiplied by a +constant and in fact if we're working in + + align:start position:0% +constant and in fact if we're working in + + + align:start position:0% +constant and in fact if we're working in +a set of units such as MKS units where + + align:start position:0% +a set of units such as MKS units where + + + align:start position:0% +a set of units such as MKS units where +the product of velocity times torque + + align:start position:0% +the product of velocity times torque + + + align:start position:0% +the product of velocity times torque +gives us power in the same units as the + + align:start position:0% +gives us power in the same units as the + + + align:start position:0% +gives us power in the same units as the +product of current times voltage these + + align:start position:0% +product of current times voltage these + + + align:start position:0% +product of current times voltage these +two KS have to be the same so uh this is + + align:start position:0% +two KS have to be the same so uh this is + + + align:start position:0% +two KS have to be the same so uh this is +this K and this K are in fact identical + + align:start position:0% +this K and this K are in fact identical + + + align:start position:0% +this K and this K are in fact identical +providing uh we're working in in MKS + + align:start position:0% +providing uh we're working in in MKS + + + align:start position:0% +providing uh we're working in in MKS +units well with that model for the motor + + align:start position:0% +units well with that model for the motor + + + align:start position:0% +units well with that model for the motor +let's go ahead and construct a block + + align:start position:0% +let's go ahead and construct a block + + + align:start position:0% +let's go ahead and construct a block +diagram for our speed control system we + + align:start position:0% +diagram for our speed control system we + + + align:start position:0% +diagram for our speed control system we +have our commanded value for Speed or + + align:start position:0% +have our commanded value for Speed or + + + align:start position:0% +have our commanded value for Speed or +shaft + + align:start position:0% +shaft + + + align:start position:0% +shaft +velocity and we have the response of the + + align:start position:0% +velocity and we have the response of the + + + align:start position:0% +velocity and we have the response of the +system out here and we subtract the two + + align:start position:0% +system out here and we subtract the two + + + align:start position:0% +system out here and we subtract the two +of them to develop an error signal we + + align:start position:0% +of them to develop an error signal we + + + align:start position:0% +of them to develop an error signal we +amplify that error signal and the + + align:start position:0% +amplify that error signal and the + + + align:start position:0% +amplify that error signal and the +resultant voltage is that that we apply + + align:start position:0% +resultant voltage is that that we apply + + + align:start position:0% +resultant voltage is that that we apply +to the motor but in order to complete + + align:start position:0% +to the motor but in order to complete + + + align:start position:0% +to the motor but in order to complete +our block diagram we have to find out + + align:start position:0% +our block diagram we have to find out + + + align:start position:0% +our block diagram we have to find out +what torque the motor + + align:start position:0% +what torque the motor + + + align:start position:0% +what torque the motor +supplies and we notice from our motor + + align:start position:0% +supplies and we notice from our motor + + + align:start position:0% +supplies and we notice from our motor +model that the torque is proportional to + + align:start position:0% +model that the torque is proportional to + + + align:start position:0% +model that the torque is proportional to +the Armature current well how do we find + + align:start position:0% +the Armature current well how do we find + + + align:start position:0% +the Armature current well how do we find +the Armature current the Armature + + align:start position:0% +the Armature current the Armature + + + align:start position:0% +the Armature current the Armature +current is equal to the voltage that we + + align:start position:0% +current is equal to the voltage that we + + + align:start position:0% +current is equal to the voltage that we +apply to the motor terminals minus the + + align:start position:0% +apply to the motor terminals minus the + + + align:start position:0% +apply to the motor terminals minus the +voltage of the back voltage generator + + align:start position:0% +voltage of the back voltage generator + + + align:start position:0% +voltage of the back voltage generator +that difference is the voltage across + + align:start position:0% +that difference is the voltage across + + + align:start position:0% +that difference is the voltage across +this resistor and if we divide that + + align:start position:0% +this resistor and if we divide that + + + align:start position:0% +this resistor and if we divide that +voltage by the value of the resistance + + align:start position:0% +voltage by the value of the resistance + + + align:start position:0% +voltage by the value of the resistance +we get the Armature current and we can + + align:start position:0% +we get the Armature current and we can + + + align:start position:0% +we get the Armature current and we can +do that on a block diagram basis by + + align:start position:0% +do that on a block diagram basis by + + + align:start position:0% +do that on a block diagram basis by +taking the voltage out of the amplifier + + align:start position:0% +taking the voltage out of the amplifier + + + align:start position:0% +taking the voltage out of the amplifier +subtracting the back voltage of the + + align:start position:0% +subtracting the back voltage of the + + + align:start position:0% +subtracting the back voltage of the +motor which we get by multiplying the + + align:start position:0% +motor which we get by multiplying the + + + align:start position:0% +motor which we get by multiplying the +motor + + align:start position:0% +motor + + + align:start position:0% +motor +velocity by K so we subtract that back + + align:start position:0% +velocity by K so we subtract that back + + + align:start position:0% +velocity by K so we subtract that back +voltage from the voltage supplied by the + + align:start position:0% +voltage from the voltage supplied by the + + + align:start position:0% +voltage from the voltage supplied by the +amplifier we D divide the resultant + + align:start position:0% +amplifier we D divide the resultant + + + align:start position:0% +amplifier we D divide the resultant +Difference by R and we get the Armature + + align:start position:0% +Difference by R and we get the Armature + + + align:start position:0% +Difference by R and we get the Armature +current once we have the Armature + + align:start position:0% +current once we have the Armature + + + align:start position:0% +current once we have the Armature +current we can get the the torque that + + align:start position:0% +current we can get the the torque that + + + align:start position:0% +current we can get the the torque that +the motor supplying + + align:start position:0% +the motor supplying + + + align:start position:0% +the motor supplying +electrically simply by multiplying that + + align:start position:0% +electrically simply by multiplying that + + + align:start position:0% +electrically simply by multiplying that +Armature current by the constant + + align:start position:0% +Armature current by the constant + + + align:start position:0% +Armature current by the constant +K so at this point in the block diagram + + align:start position:0% +K so at this point in the block diagram + + + align:start position:0% +K so at this point in the block diagram +we have the electrical torque being + + align:start position:0% +we have the electrical torque being + + + align:start position:0% +we have the electrical torque being +supplied by the motor or the torque + + align:start position:0% +supplied by the motor or the torque + + + align:start position:0% +supplied by the motor or the torque +that's a consequence of the energy + + align:start position:0% +that's a consequence of the energy + + + align:start position:0% +that's a consequence of the energy +conversion process associated with the + + align:start position:0% +conversion process associated with the + + + align:start position:0% +conversion process associated with the +motor we add to that the disturbance + + align:start position:0% +motor we add to that the disturbance + + + align:start position:0% +motor we add to that the disturbance +torque that's applied externally to the + + align:start position:0% +torque that's applied externally to the + + + align:start position:0% +torque that's applied externally to the +system and the sum of these two is the + + align:start position:0% +system and the sum of these two is the + + + align:start position:0% +system and the sum of these two is the +net torque applied to the inertia of + + align:start position:0% +net torque applied to the inertia of + + + align:start position:0% +net torque applied to the inertia of +associated with both the motor + + align:start position:0% +associated with both the motor + + + align:start position:0% +associated with both the motor +Armature and additional rotating inertia + + align:start position:0% +Armature and additional rotating inertia + + + align:start position:0% +Armature and additional rotating inertia +in the system the inertia J as we + + align:start position:0% +in the system the inertia J as we + + + align:start position:0% +in the system the inertia J as we +defined it earlier if we divide that net + + align:start position:0% +defined it earlier if we divide that net + + + align:start position:0% +defined it earlier if we divide that net +torque by J we get acceleration of the + + align:start position:0% +torque by J we get acceleration of the + + + align:start position:0% +torque by J we get acceleration of the +motor and load combination if we then + + align:start position:0% +motor and load combination if we then + + + align:start position:0% +motor and load combination if we then +integrate multiply by 1 / s we get the + + align:start position:0% +integrate multiply by 1 / s we get the + + + align:start position:0% +integrate multiply by 1 / s we get the +velocity of the motor load + + align:start position:0% +velocity of the motor load + + + align:start position:0% +velocity of the motor load +combination once we've gotten to that + + align:start position:0% +combination once we've gotten to that + + + align:start position:0% +combination once we've gotten to that +point in the block diagram of course we + + align:start position:0% +point in the block diagram of course we + + + align:start position:0% +point in the block diagram of course we +have the variable necessary to complete + + align:start position:0% +have the variable necessary to complete + + + align:start position:0% +have the variable necessary to complete +the various feedback paths we multiply + + align:start position:0% +the various feedback paths we multiply + + + align:start position:0% +the various feedback paths we multiply +by motor velocity by our constant K to + + align:start position:0% +by motor velocity by our constant K to + + + align:start position:0% +by motor velocity by our constant K to +get the back voltage associated with the + + align:start position:0% +get the back voltage associated with the + + + align:start position:0% +get the back voltage associated with the +motor similarly we bring back velocity + + align:start position:0% +motor similarly we bring back velocity + + + align:start position:0% +motor similarly we bring back velocity +information probably via some sort of a + + align:start position:0% +information probably via some sort of a + + + align:start position:0% +information probably via some sort of a +transducer as I mentioned earlier a + + align:start position:0% +transducer as I mentioned earlier a + + + align:start position:0% +transducer as I mentioned earlier a +tachometer to the input of the + + align:start position:0% +tachometer to the input of the + + + align:start position:0% +tachometer to the input of the +system well we can now look at the + + align:start position:0% +system well we can now look at the + + + align:start position:0% +system well we can now look at the +properties of this sort of a feedback + + align:start position:0% +properties of this sort of a feedback + + + align:start position:0% +properties of this sort of a feedback +system if I have a sufficiently large + + align:start position:0% +system if I have a sufficiently large + + + align:start position:0% +system if I have a sufficiently large +value for a we have a system that has + + align:start position:0% +value for a we have a system that has + + + align:start position:0% +value for a we have a system that has +unity feedback between the out put + + align:start position:0% +unity feedback between the out put + + + align:start position:0% +unity feedback between the out put +variable and our input summing point so + + align:start position:0% +variable and our input summing point so + + + align:start position:0% +variable and our input summing point so +we have a system uh which has a + + align:start position:0% +we have a system uh which has a + + + align:start position:0% +we have a system uh which has a +so-called major Loop that has an F or a + + align:start position:0% +so-called major Loop that has an F or a + + + align:start position:0% +so-called major Loop that has an F or a +feedback transfer function of one and in + + align:start position:0% +feedback transfer function of one and in + + + align:start position:0% +feedback transfer function of one and in +fact providing a is sufficiently large + + align:start position:0% +fact providing a is sufficiently large + + + align:start position:0% +fact providing a is sufficiently large +the gain from the input of the system to + + align:start position:0% +the gain from the input of the system to + + + align:start position:0% +the gain from the input of the system to +the output of the system is about equal + + align:start position:0% +the output of the system is about equal + + + align:start position:0% +the output of the system is about equal +to Unity the reciprocal of the feedback + + align:start position:0% +to Unity the reciprocal of the feedback + + + align:start position:0% +to Unity the reciprocal of the feedback +path and this tells us that for a large + + align:start position:0% +path and this tells us that for a large + + + align:start position:0% +path and this tells us that for a large +a the response speed should be just + + align:start position:0% +a the response speed should be just + + + align:start position:0% +a the response speed should be just +about equal to the commanded speed our + + align:start position:0% +about equal to the commanded speed our + + + align:start position:0% +about equal to the commanded speed our +real interest in this particular example + + align:start position:0% +real interest in this particular example + + + align:start position:0% +real interest in this particular example +however is how well the system rejects + + align:start position:0% +however is how well the system rejects + + + align:start position:0% +however is how well the system rejects +torque disturbances that are applied to + + align:start position:0% +torque disturbances that are applied to + + + align:start position:0% +torque disturbances that are applied to +the motor load combination so what we + + align:start position:0% +the motor load combination so what we + + + align:start position:0% +the motor load combination so what we +really want to do is look at the + + align:start position:0% +really want to do is look at the + + + align:start position:0% +really want to do is look at the +response the change in speed that occurs + + align:start position:0% +response the change in speed that occurs + + + align:start position:0% +response the change in speed that occurs +for a given torque disturbance we so we + + align:start position:0% +for a given torque disturbance we so we + + + align:start position:0% +for a given torque disturbance we so we +want to write the closed loop transfer + + align:start position:0% +want to write the closed loop transfer + + + align:start position:0% +want to write the closed loop transfer +function aega R over + + align:start position:0% +function aega R over + + + align:start position:0% +function aega R over +TD if we do that this expression results + + align:start position:0% +TD if we do that this expression results + + + align:start position:0% +TD if we do that this expression results +we find out that the dependence of + + align:start position:0% +we find out that the dependence of + + + align:start position:0% +we find out that the dependence of +output velocity on disturbing torque + + align:start position:0% +output velocity on disturbing torque + + + align:start position:0% +output velocity on disturbing torque +depends of course on various system + + align:start position:0% +depends of course on various system + + + align:start position:0% +depends of course on various system +parameters the multiplying factor out in + + align:start position:0% +parameters the multiplying factor out in + + + align:start position:0% +parameters the multiplying factor out in +front R over K * k + a we we can sort of + + align:start position:0% +front R over K * k + a we we can sort of + + + align:start position:0% +front R over K * k + a we we can sort of +rationalize why that ought to ought to + + align:start position:0% +rationalize why that ought to ought to + + + align:start position:0% +rationalize why that ought to ought to +be if we had a larger amplifier gain of + + align:start position:0% +be if we had a larger amplifier gain of + + + align:start position:0% +be if we had a larger amplifier gain of +course we'd get greater attenuation the + + align:start position:0% +course we'd get greater attenuation the + + + align:start position:0% +course we'd get greater attenuation the +system would be less sensitive to + + align:start position:0% +system would be less sensitive to + + + align:start position:0% +system would be less sensitive to +applied torque + + align:start position:0% +applied torque + + + align:start position:0% +applied torque +disturbances similarly if R is smaller + + align:start position:0% +disturbances similarly if R is smaller + + + align:start position:0% +disturbances similarly if R is smaller +the motor itself giv is greater current + + align:start position:0% +the motor itself giv is greater current + + + align:start position:0% +the motor itself giv is greater current +and hence greater or experiences greater + + align:start position:0% +and hence greater or experiences greater + + + align:start position:0% +and hence greater or experiences greater +Armature current and hence provides + + align:start position:0% +Armature current and hence provides + + + align:start position:0% +Armature current and hence provides +greater torque for a given voltage + + align:start position:0% +greater torque for a given voltage + + + align:start position:0% +greater torque for a given voltage +applied to the motor and so that's the + + align:start position:0% +applied to the motor and so that's the + + + align:start position:0% +applied to the motor and so that's the +reason that R appears as it does a + + align:start position:0% +reason that R appears as it does a + + + align:start position:0% +reason that R appears as it does a +smaller R leading to smaller + + align:start position:0% +smaller R leading to smaller + + + align:start position:0% +smaller R leading to smaller +disturbances similarly if the back + + align:start position:0% +disturbances similarly if the back + + + align:start position:0% +disturbances similarly if the back +voltage coefficient uh is larger the + + align:start position:0% +voltage coefficient uh is larger the + + + align:start position:0% +voltage coefficient uh is larger the +motor sort of intrinsically U tends to + + align:start position:0% +motor sort of intrinsically U tends to + + + align:start position:0% +motor sort of intrinsically U tends to +minimize disturbances applied to it + + align:start position:0% +minimize disturbances applied to it + + + align:start position:0% +minimize disturbances applied to it +velocity disturbances so this collection + + align:start position:0% +velocity disturbances so this collection + + + align:start position:0% +velocity disturbances so this collection +of constants out in front gives us the + + align:start position:0% +of constants out in front gives us the + + + align:start position:0% +of constants out in front gives us the +rejection if you will at at low + + align:start position:0% +rejection if you will at at low + + + align:start position:0% +rejection if you will at at low +frequencies this is hopefully a small + + align:start position:0% +frequencies this is hopefully a small + + + align:start position:0% +frequencies this is hopefully a small +number and then at some higher frequency + + align:start position:0% +number and then at some higher frequency + + + align:start position:0% +number and then at some higher frequency +we get a single pole associated with + + align:start position:0% +we get a single pole associated with + + + align:start position:0% +we get a single pole associated with +this transfer function rep reflecting + + align:start position:0% +this transfer function rep reflecting + + + align:start position:0% +this transfer function rep reflecting +the energy storage associated with the + + align:start position:0% +the energy storage associated with the + + + align:start position:0% +the energy storage associated with the +rotating inertia so + + align:start position:0% +rotating inertia so + + + align:start position:0% +rotating inertia so +our disturbance to controlled variable + + align:start position:0% +our disturbance to controlled variable + + + align:start position:0% +our disturbance to controlled variable +transfer function has some low frequency + + align:start position:0% +transfer function has some low frequency + + + align:start position:0% +transfer function has some low frequency +magnitude given by this expression and + + align:start position:0% +magnitude given by this expression and + + + align:start position:0% +magnitude given by this expression and +then a single pole the important point + + align:start position:0% +then a single pole the important point + + + align:start position:0% +then a single pole the important point +to note is that if we increase the + + align:start position:0% +to note is that if we increase the + + + align:start position:0% +to note is that if we increase the +inertia in this expression it doesn't + + align:start position:0% +inertia in this expression it doesn't + + + align:start position:0% +inertia in this expression it doesn't +change the low frequency rejection at + + align:start position:0% +change the low frequency rejection at + + + align:start position:0% +change the low frequency rejection at +all but what it does is lower the + + align:start position:0% +all but what it does is lower the + + + align:start position:0% +all but what it does is lower the +frequency at which the pole comes in and + + align:start position:0% +frequency at which the pole comes in and + + + align:start position:0% +frequency at which the pole comes in and +we can look at the effect on this + + align:start position:0% +we can look at the effect on this + + + align:start position:0% +we can look at the effect on this +transfer function of changing inertia in + + align:start position:0% +transfer function of changing inertia in + + + align:start position:0% +transfer function of changing inertia in +bod plot + + align:start position:0% +bod plot + + + align:start position:0% +bod plot +form and I show that over here here we + + align:start position:0% +form and I show that over here here we + + + align:start position:0% +form and I show that over here here we +plot the magnitude of the speed over the + + align:start position:0% +plot the magnitude of the speed over the + + + align:start position:0% +plot the magnitude of the speed over the +disturbance in + + align:start position:0% +disturbance in + + + align:start position:0% +disturbance in +bod plot coordinates as a function of + + align:start position:0% +bod plot coordinates as a function of + + + align:start position:0% +bod plot coordinates as a function of +frequency so what we're doing is + + align:start position:0% +frequency so what we're doing is + + + align:start position:0% +frequency so what we're doing is +measuring the sosal steady state + + align:start position:0% +measuring the sosal steady state + + + align:start position:0% +measuring the sosal steady state +rejection of disturbing torqus we're + + align:start position:0% +rejection of disturbing torqus we're + + + align:start position:0% +rejection of disturbing torqus we're +proposing an experiment where we go in + + align:start position:0% +proposing an experiment where we go in + + + align:start position:0% +proposing an experiment where we go in +and apply a sinusoidally varying torque + + align:start position:0% +and apply a sinusoidally varying torque + + + align:start position:0% +and apply a sinusoidally varying torque +to the Armature load combination and we + + align:start position:0% +to the Armature load combination and we + + + align:start position:0% +to the Armature load combination and we +look at how well the motor rejects + + align:start position:0% +look at how well the motor rejects + + + align:start position:0% +look at how well the motor rejects +that uh there's a DC value which was + + align:start position:0% +that uh there's a DC value which was + + + align:start position:0% +that uh there's a DC value which was +given in our earlier expression that's R + + align:start position:0% +given in our earlier expression that's R + + + align:start position:0% +given in our earlier expression that's R +over K * k + a so that's the low + + align:start position:0% +over K * k + a so that's the low + + + align:start position:0% +over K * k + a so that's the low +frequency value + + align:start position:0% +frequency value + + + align:start position:0% +frequency value +and then there's a corner frequency + + align:start position:0% +and then there's a corner frequency + + + align:start position:0% +and then there's a corner frequency +associated with the system and it + + align:start position:0% +associated with the system and it + + + align:start position:0% +associated with the system and it +involves a collection of constants but + + align:start position:0% +involves a collection of constants but + + + align:start position:0% +involves a collection of constants but +the important point is that that corner + + align:start position:0% +the important point is that that corner + + + align:start position:0% +the important point is that that corner +frequency is inversely proportional to + + align:start position:0% +frequency is inversely proportional to + + + align:start position:0% +frequency is inversely proportional to +the total inertia it's inversely + + align:start position:0% +the total inertia it's inversely + + + align:start position:0% +the total inertia it's inversely +proportional to + + align:start position:0% +proportional to + + + align:start position:0% +proportional to +J and so if we add an additional J we + + align:start position:0% +J and so if we add an additional J we + + + align:start position:0% +J and so if we add an additional J we +build up our system uh we adjust k for + + align:start position:0% +build up our system uh we adjust k for + + + align:start position:0% +build up our system uh we adjust k for +example uh in order to control our our + + align:start position:0% +example uh in order to control our our + + + align:start position:0% +example uh in order to control our our +DC sensitivity to the level that we'd + + align:start position:0% +DC sensitivity to the level that we'd + + + align:start position:0% +DC sensitivity to the level that we'd +like to have it um we then can by + + align:start position:0% +like to have it um we then can by + + + align:start position:0% +like to have it um we then can by +appropriate choice of J ensure that the + + align:start position:0% +appropriate choice of J ensure that the + + + align:start position:0% +appropriate choice of J ensure that the +system crosses over before higher order + + align:start position:0% +system crosses over before higher order + + + align:start position:0% +system crosses over before higher order +poles in the system transfer function + + align:start position:0% +poles in the system transfer function + + + align:start position:0% +poles in the system transfer function +become important so we can ensure that + + align:start position:0% +become important so we can ensure that + + + align:start position:0% +become important so we can ensure that +we have stability uh possibly as much as + + align:start position:0% +we have stability uh possibly as much as + + + align:start position:0% +we have stability uh possibly as much as +90 degrees of phase margin by forcing + + align:start position:0% +90 degrees of phase margin by forcing + + + align:start position:0% +90 degrees of phase margin by forcing +Crossover at a sufficiently low + + align:start position:0% +Crossover at a sufficiently low + + + align:start position:0% +Crossover at a sufficiently low +frequency through appropriate choice of + + align:start position:0% +frequency through appropriate choice of + + + align:start position:0% +frequency through appropriate choice of +J and as we make J larger the system + + align:start position:0% +J and as we make J larger the system + + + align:start position:0% +J and as we make J larger the system +performance improves the rejection of + + align:start position:0% +performance improves the rejection of + + + align:start position:0% +performance improves the rejection of +the system gets better because an + + align:start position:0% +the system gets better because an + + + align:start position:0% +the system gets better because an +increasing J lowers the frequency of + + align:start position:0% +increasing J lowers the frequency of + + + align:start position:0% +increasing J lowers the frequency of +this + + align:start position:0% +this + + + align:start position:0% +this +pole for example we might get this sort + + align:start position:0% +pole for example we might get this sort + + + align:start position:0% +pole for example we might get this sort +of a transfer function when we increase + + align:start position:0% +of a transfer function when we increase + + + align:start position:0% +of a transfer function when we increase +J and so this then in our body plot is + + align:start position:0% +J and so this then in our body plot is + + + align:start position:0% +J and so this then in our body plot is +the direction of increasing + + align:start position:0% + + + + align:start position:0% + +inertia and we see that the rejection of + + align:start position:0% +inertia and we see that the rejection of + + + align:start position:0% +inertia and we see that the rejection of +the system remember we'd ideally like to + + align:start position:0% +the system remember we'd ideally like to + + + align:start position:0% +the system remember we'd ideally like to +have this transfer function zero we'd + + align:start position:0% +have this transfer function zero we'd + + + align:start position:0% +have this transfer function zero we'd +ideally like to have no change in speed + + align:start position:0% +ideally like to have no change in speed + + + align:start position:0% +ideally like to have no change in speed +for a given torque disturbance but we + + align:start position:0% +for a given torque disturbance but we + + + align:start position:0% +for a given torque disturbance but we +push the first pole down as we increase + + align:start position:0% +push the first pole down as we increase + + + align:start position:0% +push the first pole down as we increase +J and in fact in the limit uh we could + + align:start position:0% +J and in fact in the limit uh we could + + + align:start position:0% +J and in fact in the limit uh we could +increase the band of frequencies over + + align:start position:0% +increase the band of frequencies over + + + align:start position:0% +increase the band of frequencies over +which we got very high attenuation by + + align:start position:0% +which we got very high attenuation by + + + align:start position:0% +which we got very high attenuation by +using a sufficiently large rotating + + align:start position:0% +using a sufficiently large rotating + + + align:start position:0% +using a sufficiently large rotating +inertia so in this is one important + + align:start position:0% +inertia so in this is one important + + + align:start position:0% +inertia so in this is one important +class of + + align:start position:0% +class of + + + align:start position:0% +class of +systems Regulators where the objective + + align:start position:0% +systems Regulators where the objective + + + align:start position:0% +systems Regulators where the objective +is + + align:start position:0% +is + + + align:start position:0% +is +to reduce or ideally eliminate a + + align:start position:0% +to reduce or ideally eliminate a + + + align:start position:0% +to reduce or ideally eliminate a +disturbance why creating a dominant pole + + align:start position:0% +disturbance why creating a dominant pole + + + align:start position:0% +disturbance why creating a dominant pole +is probably the compensation Form of + + align:start position:0% +is probably the compensation Form of + + + align:start position:0% +is probably the compensation Form of +choice + + align:start position:0% +choice + + + align:start position:0% +choice +particularly if we can locate the + + align:start position:0% +particularly if we can locate the + + + align:start position:0% +particularly if we can locate the +dominant pole at the output if we can + + align:start position:0% +dominant pole at the output if we can + + + align:start position:0% +dominant pole at the output if we can +put our energy storage that creates the + + align:start position:0% +put our energy storage that creates the + + + align:start position:0% +put our energy storage that creates the +dominant pole at the output of the + + align:start position:0% +dominant pole at the output of the + + + align:start position:0% +dominant pole at the output of the +system our attempts to reduce + + align:start position:0% +system our attempts to reduce + + + align:start position:0% +system our attempts to reduce +disturbances are greatly aided by the + + align:start position:0% +disturbances are greatly aided by the + + + align:start position:0% +disturbances are greatly aided by the +inertia or in the case of the power + + align:start position:0% +inertia or in the case of the power + + + align:start position:0% +inertia or in the case of the power +supply the electrical power supply the + + align:start position:0% +supply the electrical power supply the + + + align:start position:0% +supply the electrical power supply the +energy storage and the capacitor that we + + align:start position:0% +energy storage and the capacitor that we + + + align:start position:0% +energy storage and the capacitor that we +attach to the + + align:start position:0% +attach to the + + + align:start position:0% +attach to the +output well suppose we have a system + + align:start position:0% +output well suppose we have a system + + + align:start position:0% +output well suppose we have a system +where we can't + + align:start position:0% +where we can't + + + align:start position:0% +where we can't +tolerate the bandwidth decrease that + + align:start position:0% +tolerate the bandwidth decrease that + + + align:start position:0% +tolerate the bandwidth decrease that +comes via cre a dominant Pole or that + + align:start position:0% +comes via cre a dominant Pole or that + + + align:start position:0% +comes via cre a dominant Pole or that +comes along with creating a dominant + + align:start position:0% +comes along with creating a dominant + + + align:start position:0% +comes along with creating a dominant +pole there are other modifications that + + align:start position:0% +pole there are other modifications that + + + align:start position:0% +pole there are other modifications that +we can make to the loop Transmission in + + align:start position:0% +we can make to the loop Transmission in + + + align:start position:0% +we can make to the loop Transmission in +order to improve the stability of the + + align:start position:0% +order to improve the stability of the + + + align:start position:0% +order to improve the stability of the +system and typically uh they retain more + + align:start position:0% +system and typically uh they retain more + + + align:start position:0% +system and typically uh they retain more +more desensitivity than does the option + + align:start position:0% +more desensitivity than does the option + + + align:start position:0% +more desensitivity than does the option +of creating a dominant pole and possibly + + align:start position:0% +of creating a dominant pole and possibly + + + align:start position:0% +of creating a dominant pole and possibly +retain more of the system bandwidth than + + align:start position:0% +retain more of the system bandwidth than + + + align:start position:0% +retain more of the system bandwidth than +would occur if we forced a dominant pole + + align:start position:0% +would occur if we forced a dominant pole + + + align:start position:0% +would occur if we forced a dominant pole +and let's look at the kinds of things we + + align:start position:0% +and let's look at the kinds of things we + + + align:start position:0% +and let's look at the kinds of things we +might like to + + align:start position:0% +might like to + + + align:start position:0% +might like to +do here again I've shown a bod plot for + + align:start position:0% +do here again I've shown a bod plot for + + + align:start position:0% +do here again I've shown a bod plot for +the AF product for some hypothetical + + align:start position:0% +the AF product for some hypothetical + + + align:start position:0% +the AF product for some hypothetical +feedback system this time I've show + + align:start position:0% +feedback system this time I've show + + + align:start position:0% +feedback system this time I've show +showed a stable one uh the + + align:start position:0% +showed a stable one uh the + + + align:start position:0% +showed a stable one uh the +magnitude is flat at DC uh possibly a + + align:start position:0% +magnitude is flat at DC uh possibly a + + + align:start position:0% +magnitude is flat at DC uh possibly a +single pole roll off in this region and + + align:start position:0% +single pole roll off in this region and + + + align:start position:0% +single pole roll off in this region and +then some higher order poles or + + align:start position:0% +then some higher order poles or + + + align:start position:0% +then some higher order poles or +additional Dynamics at higher + + align:start position:0% +additional Dynamics at higher + + + align:start position:0% +additional Dynamics at higher +frequencies an Associated angle might be + + align:start position:0% +frequencies an Associated angle might be + + + align:start position:0% +frequencies an Associated angle might be +one that was near 0 degrees at at low + + align:start position:0% +one that was near 0 degrees at at low + + + align:start position:0% +one that was near 0 degrees at at low +frequencies uh here's the 180° point or + + align:start position:0% +frequencies uh here's the 180° point or + + + align:start position:0% +frequencies uh here's the 180° point or +minus 180° point start out close to zero + + align:start position:0% +minus 180° point start out close to zero + + + align:start position:0% +minus 180° point start out close to zero +we get about 90° of phase shift + + align:start position:0% +we get about 90° of phase shift + + + align:start position:0% +we get about 90° of phase shift +reflecting this first pole and then at + + align:start position:0% +reflecting this first pole and then at + + + align:start position:0% +reflecting this first pole and then at +higher frequencies again reflecting the + + align:start position:0% +higher frequencies again reflecting the + + + align:start position:0% +higher frequencies again reflecting the +energy storage or the other modes of + + align:start position:0% +energy storage or the other modes of + + + align:start position:0% +energy storage or the other modes of +energy storage in the system the angle + + align:start position:0% +energy storage in the system the angle + + + align:start position:0% +energy storage in the system the angle +associated with the AF product begins to + + align:start position:0% +associated with the AF product begins to + + + align:start position:0% +associated with the AF product begins to +drop off eventually goes through minus + + align:start position:0% +drop off eventually goes through minus + + + align:start position:0% +drop off eventually goes through minus +180° in this case uh I've assumed that + + align:start position:0% +180° in this case uh I've assumed that + + + align:start position:0% +180° in this case uh I've assumed that +the system is stable in other words the + + align:start position:0% +the system is stable in other words the + + + align:start position:0% +the system is stable in other words the +way I've drawn things we go through + + align:start position:0% +way I've drawn things we go through + + + align:start position:0% +way I've drawn things we go through +Unity + + align:start position:0% +Unity + + + align:start position:0% +Unity +magnitude before the angle gets to- 180° + + align:start position:0% +magnitude before the angle gets to- 180° + + + align:start position:0% +magnitude before the angle gets to- 180° +but I've also tried to show in the + + align:start position:0% +but I've also tried to show in the + + + align:start position:0% +but I've also tried to show in the +drawing that we have a very small amount + + align:start position:0% +drawing that we have a very small amount + + + align:start position:0% +drawing that we have a very small amount +of phase margin in this case we might + + align:start position:0% +of phase margin in this case we might + + + align:start position:0% +of phase margin in this case we might +not feel that the system has adequate + + align:start position:0% +not feel that the system has adequate + + + align:start position:0% +not feel that the system has adequate +stability let's see what we're able to + + align:start position:0% +stability let's see what we're able to + + + align:start position:0% +stability let's see what we're able to +do to improve that + + align:start position:0% +do to improve that + + + align:start position:0% +do to improve that +situation the U kinds of modifications + + align:start position:0% +situation the U kinds of modifications + + + align:start position:0% +situation the U kinds of modifications +we might like to make are the following + + align:start position:0% +we might like to make are the following + + + align:start position:0% +we might like to make are the following +suppose we could do something to + + align:start position:0% +suppose we could do something to + + + align:start position:0% +suppose we could do something to +increase the angle associated with a + + align:start position:0% +increase the angle associated with a + + + align:start position:0% +increase the angle associated with a +transfer function or with Loop + + align:start position:0% +transfer function or with Loop + + + align:start position:0% +transfer function or with Loop +transmission out in this region if we + + align:start position:0% +transmission out in this region if we + + + align:start position:0% +transmission out in this region if we +could somehow push up the angle and do + + align:start position:0% +could somehow push up the angle and do + + + align:start position:0% +could somehow push up the angle and do +that in a way that didn't increase + + align:start position:0% +that in a way that didn't increase + + + align:start position:0% +that in a way that didn't increase +crossover frequency here we've shown the + + align:start position:0% +crossover frequency here we've shown the + + + align:start position:0% +crossover frequency here we've shown the +crossover frequency of the system uh if + + align:start position:0% +crossover frequency of the system uh if + + + align:start position:0% +crossover frequency of the system uh if +we could do that in a way that didn't + + align:start position:0% +we could do that in a way that didn't + + + align:start position:0% +we could do that in a way that didn't +increase the crossover frequency so that + + align:start position:0% +increase the crossover frequency so that + + + align:start position:0% +increase the crossover frequency so that +we didn't get additional negative phase + + align:start position:0% +we didn't get additional negative phase + + + align:start position:0% +we didn't get additional negative phase +shift associated with the uncompensated + + align:start position:0% +shift associated with the uncompensated + + + align:start position:0% +shift associated with the uncompensated +system hurting is we could just push up + + align:start position:0% +system hurting is we could just push up + + + align:start position:0% +system hurting is we could just push up +this magnitude this angle but keep the + + align:start position:0% +this magnitude this angle but keep the + + + align:start position:0% +this magnitude this angle but keep the +magnitude the same out here that would + + align:start position:0% +magnitude the same out here that would + + + align:start position:0% +magnitude the same out here that would +certainly help if we could make this + + align:start position:0% +certainly help if we could make this + + + align:start position:0% +certainly help if we could make this +angle more positive of course we'd + + align:start position:0% +angle more positive of course we'd + + + align:start position:0% +angle more positive of course we'd +increase the phase margin of the system + + align:start position:0% +increase the phase margin of the system + + + align:start position:0% +increase the phase margin of the system +and thereby improve the stability so + + align:start position:0% +and thereby improve the stability so + + + align:start position:0% +and thereby improve the stability so +that's one thing that that we might like + + align:start position:0% +that's one thing that that we might like + + + align:start position:0% +that's one thing that that we might like +to + + align:start position:0% +to + + + align:start position:0% +to +do another thing that we might like to + + align:start position:0% +do another thing that we might like to + + + align:start position:0% +do another thing that we might like to +do is somehow push down the magnitude + + align:start position:0% +do is somehow push down the magnitude + + + align:start position:0% +do is somehow push down the magnitude +but not at all frequencies we spoke last + + align:start position:0% +but not at all frequencies we spoke last + + + align:start position:0% +but not at all frequencies we spoke last +time about simply lowering the a fnot + + align:start position:0% +time about simply lowering the a fnot + + + align:start position:0% +time about simply lowering the a fnot +product which of course pushes down the + + align:start position:0% +product which of course pushes down the + + + align:start position:0% +product which of course pushes down the +magnitude at all frequencies the + + align:start position:0% +magnitude at all frequencies the + + + align:start position:0% +magnitude at all frequencies the +disadvantage to that approach is that it + + align:start position:0% +disadvantage to that approach is that it + + + align:start position:0% +disadvantage to that approach is that it +lowers desensitivity at all frequencies + + align:start position:0% +lowers desensitivity at all frequencies + + + align:start position:0% +lowers desensitivity at all frequencies +suppose we could find a way of modifying + + align:start position:0% +suppose we could find a way of modifying + + + align:start position:0% +suppose we could find a way of modifying +the loop transmission so that we push + + align:start position:0% +the loop transmission so that we push + + + align:start position:0% +the loop transmission so that we push +down the magnitude in this vicinity so + + align:start position:0% +down the magnitude in this vicinity so + + + align:start position:0% +down the magnitude in this vicinity so +that we crossed over at a lower + + align:start position:0% +that we crossed over at a lower + + + align:start position:0% +that we crossed over at a lower +frequency without making a significant + + align:start position:0% +frequency without making a significant + + + align:start position:0% +frequency without making a significant +change in the angle if that were the + + align:start position:0% +change in the angle if that were the + + + align:start position:0% +change in the angle if that were the +case crossover frequency would lower + + align:start position:0% +case crossover frequency would lower + + + align:start position:0% +case crossover frequency would lower +we'd still have our original + + align:start position:0% +we'd still have our original + + + align:start position:0% +we'd still have our original +desensitivity at lower frequencies + + align:start position:0% +desensitivity at lower frequencies + + + align:start position:0% +desensitivity at lower frequencies +because the crossover frequency lowers + + align:start position:0% +because the crossover frequency lowers + + + align:start position:0% +because the crossover frequency lowers +we'd end up with a greater amount of + + align:start position:0% +we'd end up with a greater amount of + + + align:start position:0% +we'd end up with a greater amount of +phase margin so those those are the two + + align:start position:0% +phase margin so those those are the two + + + align:start position:0% +phase margin so those those are the two +things we might like to do either push + + align:start position:0% +things we might like to do either push + + + align:start position:0% +things we might like to do either push +up the angle portion of the bod plot in + + align:start position:0% +up the angle portion of the bod plot in + + + align:start position:0% +up the angle portion of the bod plot in +the vicinity of the crossover frequency + + align:start position:0% +the vicinity of the crossover frequency + + + align:start position:0% +the vicinity of the crossover frequency +without making a corresponding change in + + align:start position:0% +without making a corresponding change in + + + align:start position:0% +without making a corresponding change in +the crossover frequency or a + + align:start position:0% +the crossover frequency or a + + + align:start position:0% +the crossover frequency or a +corresponding change in the magnitude + + align:start position:0% +corresponding change in the magnitude + + + align:start position:0% +corresponding change in the magnitude +or push down the magnitude curve in the + + align:start position:0% +or push down the magnitude curve in the + + + align:start position:0% +or push down the magnitude curve in the +vicinity of crossover to lower crossover + + align:start position:0% +vicinity of crossover to lower crossover + + + align:start position:0% +vicinity of crossover to lower crossover +without making changes or significant + + align:start position:0% +without making changes or significant + + + align:start position:0% +without making changes or significant +changes at much lower frequencies and + + align:start position:0% +changes at much lower frequencies and + + + align:start position:0% +changes at much lower frequencies and +without modifying the angle associated + + align:start position:0% +without modifying the angle associated + + + align:start position:0% +without modifying the angle associated +with the transfer function well + + align:start position:0% +with the transfer function well + + + align:start position:0% +with the transfer function well +unfortunately our ability to do that + + align:start position:0% +unfortunately our ability to do that + + + align:start position:0% +unfortunately our ability to do that +limited the implications of physical + + align:start position:0% +limited the implications of physical + + + align:start position:0% +limited the implications of physical +realizability uh tell us that there's a + + align:start position:0% +realizability uh tell us that there's a + + + align:start position:0% +realizability uh tell us that there's a +relationship between the magnitude and + + align:start position:0% +relationship between the magnitude and + + + align:start position:0% +relationship between the magnitude and +the angle of a transfer function and in + + align:start position:0% +the angle of a transfer function and in + + + align:start position:0% +the angle of a transfer function and in +fact the kinds of things we like to do + + align:start position:0% +fact the kinds of things we like to do + + + align:start position:0% +fact the kinds of things we like to do +we really can't do with finite with + + align:start position:0% +we really can't do with finite with + + + align:start position:0% +we really can't do with finite with +elements that contain a finite number of + + align:start position:0% +elements that contain a finite number of + + + align:start position:0% +elements that contain a finite number of +of of + + align:start position:0% +of of + + + align:start position:0% +of of +elements uh consider for example a a + + align:start position:0% +elements uh consider for example a a + + + align:start position:0% +elements uh consider for example a a +transfer function that does uh the first + + align:start position:0% +transfer function that does uh the first + + + align:start position:0% +transfer function that does uh the first +operation one that gives us positive + + align:start position:0% +operation one that gives us positive + + + align:start position:0% +operation one that gives us positive +phase shift without corresponding + + align:start position:0% +phase shift without corresponding + + + align:start position:0% +phase shift without corresponding +magnitude changes such a transfer + + align:start position:0% +magnitude changes such a transfer + + + align:start position:0% +magnitude changes such a transfer +function is e to the Plus St but + + align:start position:0% +function is e to the Plus St but + + + align:start position:0% +function is e to the Plus St but +unfortunately e to the plus s to is the + + align:start position:0% +unfortunately e to the plus s to is the + + + align:start position:0% +unfortunately e to the plus s to is the +transfer function of an element that + + align:start position:0% +transfer function of an element that + + + align:start position:0% +transfer function of an element that +predicts in other words the impulse + + align:start position:0% +predicts in other words the impulse + + + align:start position:0% +predicts in other words the impulse +response of an an element whose transfer + + align:start position:0% +response of an an element whose transfer + + + align:start position:0% +response of an an element whose transfer +function is e to the Plus St is an + + align:start position:0% +function is e to the Plus St is an + + + align:start position:0% +function is e to the Plus St is an +Impulse that occurs exactly to seconds + + align:start position:0% +Impulse that occurs exactly to seconds + + + align:start position:0% +Impulse that occurs exactly to seconds +before we put in the original impulse + + align:start position:0% +before we put in the original impulse + + + align:start position:0% +before we put in the original impulse +and consequently obviously a physically + + align:start position:0% +and consequently obviously a physically + + + align:start position:0% +and consequently obviously a physically +unrealizable Network in fact if we had + + align:start position:0% +unrealizable Network in fact if we had + + + align:start position:0% +unrealizable Network in fact if we had +such a network there's far probably far + + align:start position:0% +such a network there's far probably far + + + align:start position:0% +such a network there's far probably far +better things to do with it than waste + + align:start position:0% +better things to do with it than waste + + + align:start position:0% +better things to do with it than waste +it on feedback systems we can get + + align:start position:0% +it on feedback systems we can get + + + align:start position:0% +it on feedback systems we can get +tomorrow stock market reports and that + + align:start position:0% +tomorrow stock market reports and that + + + align:start position:0% +tomorrow stock market reports and that +sort of thing and not waste it on + + align:start position:0% +sort of thing and not waste it on + + + align:start position:0% +sort of thing and not waste it on +building feedback systems so those kinds + + align:start position:0% +building feedback systems so those kinds + + + align:start position:0% +building feedback systems so those kinds +of things we we we're not really + + align:start position:0% +of things we we we're not really + + + align:start position:0% +of things we we we're not really +completely able to do we don't have the + + align:start position:0% +completely able to do we don't have the + + + align:start position:0% +completely able to do we don't have the +complete Freedom we'd like to have to + + align:start position:0% +complete Freedom we'd like to have to + + + align:start position:0% +complete Freedom we'd like to have to +make the kinds of changes that would + + align:start position:0% +make the kinds of changes that would + + + align:start position:0% +make the kinds of changes that would +give us the greatest Improvement in the + + align:start position:0% +give us the greatest Improvement in the + + + align:start position:0% +give us the greatest Improvement in the +stability of our feedback system but we + + align:start position:0% +stability of our feedback system but we + + + align:start position:0% +stability of our feedback system but we +do have some degrees of freedom and in + + align:start position:0% +do have some degrees of freedom and in + + + align:start position:0% +do have some degrees of freedom and in +fact the simple transfer functions that + + align:start position:0% +fact the simple transfer functions that + + + align:start position:0% +fact the simple transfer functions that +work in this direction are th those that + + align:start position:0% +work in this direction are th those that + + + align:start position:0% +work in this direction are th those that +include pole zero doublets a single pole + + align:start position:0% +include pole zero doublets a single pole + + + align:start position:0% +include pole zero doublets a single pole +and a single zero are the simplest forms + + align:start position:0% +and a single zero are the simplest forms + + + align:start position:0% +and a single zero are the simplest forms +of networks that go in this direction or + + align:start position:0% +of networks that go in this direction or + + + align:start position:0% +of networks that go in this direction or +the simplest forms of transfer functions + + align:start position:0% +the simplest forms of transfer functions + + + align:start position:0% +the simplest forms of transfer functions +that go in this + + align:start position:0% +that go in this + + + align:start position:0% +that go in this +Direction one of the transfer functions + + align:start position:0% +Direction one of the transfer functions + + + align:start position:0% +Direction one of the transfer functions +that we're interested in and that we can + + align:start position:0% +that we're interested in and that we can + + + align:start position:0% +that we're interested in and that we can +use to improve the performance of + + align:start position:0% +use to improve the performance of + + + align:start position:0% +use to improve the performance of +feedback systems is is called a lead + + align:start position:0% +feedback systems is is called a lead + + + align:start position:0% +feedback systems is is called a lead +transfer function and the output over + + align:start position:0% +transfer function and the output over + + + align:start position:0% +transfer function and the output over +the input for that sort of system as a + + align:start position:0% +the input for that sort of system as a + + + align:start position:0% +the input for that sort of system as a +function of s uh is one that combines a + + align:start position:0% +function of s uh is one that combines a + + + align:start position:0% +function of s uh is one that combines a +low frequency zero with a Pole located + + align:start position:0% +low frequency zero with a Pole located + + + align:start position:0% +low frequency zero with a Pole located +at a higher frequency in this + + align:start position:0% +at a higher frequency in this + + + align:start position:0% +at a higher frequency in this +representation we assume that Alpha is a + + align:start position:0% +representation we assume that Alpha is a + + + align:start position:0% +representation we assume that Alpha is a +number larger than one consequently we + + align:start position:0% +number larger than one consequently we + + + align:start position:0% +number larger than one consequently we +get a zero in the lead transfer function + + align:start position:0% +get a zero in the lead transfer function + + + align:start position:0% +get a zero in the lead transfer function +at a relatively lower frequency than the + + align:start position:0% +at a relatively lower frequency than the + + + align:start position:0% +at a relatively lower frequency than the +pole if I normalize the expression by + + align:start position:0% +pole if I normalize the expression by + + + align:start position:0% +pole if I normalize the expression by +bringing a one over Alpha out in front I + + align:start position:0% +bringing a one over Alpha out in front I + + + align:start position:0% +bringing a one over Alpha out in front I +get a an expression that can be realized + + align:start position:0% +get a an expression that can be realized + + + align:start position:0% +get a an expression that can be realized +with a simple passive Network and so + + align:start position:0% +with a simple passive Network and so + + + align:start position:0% +with a simple passive Network and so +very frequently a lead type transfer + + align:start position:0% +very frequently a lead type transfer + + + align:start position:0% +very frequently a lead type transfer +function is written as 1 over alpha + + align:start position:0% +function is written as 1 over alpha + + + align:start position:0% +function is written as 1 over alpha +alpha to S +1 over to S + one the lead + + align:start position:0% +alpha to S +1 over to S + one the lead + + + align:start position:0% +alpha to S +1 over to S + one the lead +type transfer function as the name name + + align:start position:0% +type transfer function as the name name + + + align:start position:0% +type transfer function as the name name +implies gives us positive or leading + + align:start position:0% +implies gives us positive or leading + + + align:start position:0% +implies gives us positive or leading +phase shift actually at all frequencies + + align:start position:0% +phase shift actually at all frequencies + + + align:start position:0% +phase shift actually at all frequencies +but with the greatest positive phase + + align:start position:0% +but with the greatest positive phase + + + align:start position:0% +but with the greatest positive phase +shift occur uring between the zero and + + align:start position:0% +shift occur uring between the zero and + + + align:start position:0% +shift occur uring between the zero and +the + + align:start position:0% + + + + align:start position:0% + +pole if we'd like to have something to + + align:start position:0% +pole if we'd like to have something to + + + align:start position:0% +pole if we'd like to have something to +look at we can mechanize a lead type + + align:start position:0% +look at we can mechanize a lead type + + + align:start position:0% +look at we can mechanize a lead type +transfer function with a simple Network + + align:start position:0% +transfer function with a simple Network + + + align:start position:0% +transfer function with a simple Network +shown here two resistors and a single + + align:start position:0% +shown here two resistors and a single + + + align:start position:0% +shown here two resistors and a single +capacitor if we Define 1/ Alpha as being + + align:start position:0% +capacitor if we Define 1/ Alpha as being + + + align:start position:0% +capacitor if we Define 1/ Alpha as being +equal to the attenuation ratio R2 over + + align:start position:0% +equal to the attenuation ratio R2 over + + + align:start position:0% +equal to the attenuation ratio R2 over +r1+ + + align:start position:0% +r1+ + + + align:start position:0% +r1+ +R2 why the low frequency gain of this + + align:start position:0% +R2 why the low frequency gain of this + + + align:start position:0% +R2 why the low frequency gain of this +network is of course uh simply one over + + align:start position:0% +network is of course uh simply one over + + + align:start position:0% +network is of course uh simply one over +Alpha at low frequencies the capacitor + + align:start position:0% +Alpha at low frequencies the capacitor + + + align:start position:0% +Alpha at low frequencies the capacitor +has no influence on the performance of + + align:start position:0% +has no influence on the performance of + + + align:start position:0% +has no influence on the performance of +the network at high frequencies the gain + + align:start position:0% +the network at high frequencies the gain + + + align:start position:0% +the network at high frequencies the gain +becomes one and so we have a transfer + + align:start position:0% +becomes one and so we have a transfer + + + align:start position:0% +becomes one and so we have a transfer +function that must have a zero uh that + + align:start position:0% +function that must have a zero uh that + + + align:start position:0% +function that must have a zero uh that +causes the gain to increase from its low + + align:start position:0% +causes the gain to increase from its low + + + align:start position:0% +causes the gain to increase from its low +frequency value we have a single pole + + align:start position:0% +frequency value we have a single pole + + + align:start position:0% +frequency value we have a single pole +that eventually causes the gain to + + align:start position:0% +that eventually causes the gain to + + + align:start position:0% +that eventually causes the gain to +flatten out out if you simply write the + + align:start position:0% +flatten out out if you simply write the + + + align:start position:0% +flatten out out if you simply write the +network Expressions you find out that + + align:start position:0% +network Expressions you find out that + + + align:start position:0% +network Expressions you find out that +you get this form uh the zero at a + + align:start position:0% +you get this form uh the zero at a + + + align:start position:0% +you get this form uh the zero at a +relatively lower frequency than the pole + + align:start position:0% +relatively lower frequency than the pole + + + align:start position:0% +relatively lower frequency than the pole +for the V out over Vin transfer function + + align:start position:0% +for the V out over Vin transfer function + + + align:start position:0% +for the V out over Vin transfer function +where Alpha and the time constant are as + + align:start position:0% +where Alpha and the time constant are as + + + align:start position:0% +where Alpha and the time constant are as +defined here so here's a a simple + + align:start position:0% +defined here so here's a a simple + + + align:start position:0% +defined here so here's a a simple +electrical Network that provides an + + align:start position:0% +electrical Network that provides an + + + align:start position:0% +electrical Network that provides an +output over input transfer function + + align:start position:0% +output over input transfer function + + + align:start position:0% +output over input transfer function +which has lead type characteristics + + align:start position:0% +which has lead type characteristics + + + align:start position:0% +which has lead type characteristics +we can look at both the magnitude and + + align:start position:0% +we can look at both the magnitude and + + + align:start position:0% +we can look at both the magnitude and +the angle associated with that sort of + + align:start position:0% +the angle associated with that sort of + + + align:start position:0% +the angle associated with that sort of +lead transfer function here's the + + align:start position:0% + + + + align:start position:0% + +magnitude uh for several different + + align:start position:0% +magnitude uh for several different + + + align:start position:0% +magnitude uh for several different +values of alpha here we have an alpha + + align:start position:0% +values of alpha here we have an alpha + + + align:start position:0% +values of alpha here we have an alpha +equals 20 so we start out at low + + align:start position:0% +equals 20 so we start out at low + + + align:start position:0% +equals 20 so we start out at low +frequencies with a magnitude of 12th + + align:start position:0% +frequencies with a magnitude of 12th + + + align:start position:0% +frequencies with a magnitude of 12th +05 in this case we're normaliz to a + + align:start position:0% +05 in this case we're normaliz to a + + + align:start position:0% +05 in this case we're normaliz to a +common pole location for all of the + + align:start position:0% +common pole location for all of the + + + align:start position:0% +common pole location for all of the +networks the pole location being one + + align:start position:0% +networks the pole location being one + + + align:start position:0% +networks the pole location being one +unit on the frequency axis uh in the + + align:start position:0% +unit on the frequency axis uh in the + + + align:start position:0% +unit on the frequency axis uh in the +case of alpha equals 20 our zero would + + align:start position:0% +case of alpha equals 20 our zero would + + + align:start position:0% +case of alpha equals 20 our zero would +occur a factor of 20 below that at + + align:start position:0% +occur a factor of 20 below that at + + + align:start position:0% +occur a factor of 20 below that at +0.005 units and we then get basically a + + align:start position:0% +0.005 units and we then get basically a + + + align:start position:0% +0.005 units and we then get basically a +single zero rise in this region then we + + align:start position:0% +single zero rise in this region then we + + + align:start position:0% +single zero rise in this region then we +get the pole associated with the lead + + align:start position:0% +get the pole associated with the lead + + + align:start position:0% +get the pole associated with the lead +type Network similarly if we look at the + + align:start position:0% +type Network similarly if we look at the + + + align:start position:0% +type Network similarly if we look at the +lead characteristics for Alpha equals 10 + + align:start position:0% +lead characteristics for Alpha equals 10 + + + align:start position:0% +lead characteristics for Alpha equals 10 +why we get this characteristic a tenth + + align:start position:0% +why we get this characteristic a tenth + + + align:start position:0% +why we get this characteristic a tenth +at low frequencies a zero location at a + + align:start position:0% +at low frequencies a zero location at a + + + align:start position:0% +at low frequencies a zero location at a +tenth of unit on the frequency axis and + + align:start position:0% +tenth of unit on the frequency axis and + + + align:start position:0% +tenth of unit on the frequency axis and +similarly for Alpha equals 5 so this + + align:start position:0% +similarly for Alpha equals 5 so this + + + align:start position:0% +similarly for Alpha equals 5 so this +then is the magnitude associated with a + + align:start position:0% +then is the magnitude associated with a + + + align:start position:0% +then is the magnitude associated with a +lead Network and we show parametrically + + align:start position:0% +lead Network and we show parametrically + + + align:start position:0% +lead Network and we show parametrically +the behavior for various values of + + align:start position:0% +the behavior for various values of + + + align:start position:0% +the behavior for various values of +alpha we can look at the angle at the + + align:start position:0% +alpha we can look at the angle at the + + + align:start position:0% +alpha we can look at the angle at the +same time or for the same kind of + + align:start position:0% +same time or for the same kind of + + + align:start position:0% +same time or for the same kind of +transfer + + align:start position:0% + + + + align:start position:0% + +function and here is the angle + + align:start position:0% +function and here is the angle + + + align:start position:0% +function and here is the angle +associated with the lead type trans ER + + align:start position:0% +associated with the lead type trans ER + + + align:start position:0% +associated with the lead type trans ER +function we notice that even for a + + align:start position:0% +function we notice that even for a + + + align:start position:0% +function we notice that even for a +relatively small value of alpha we get a + + align:start position:0% +relatively small value of alpha we get a + + + align:start position:0% +relatively small value of alpha we get a +positive phase shift whose maximum value + + align:start position:0% +positive phase shift whose maximum value + + + align:start position:0% +positive phase shift whose maximum value +actually occurs at the geometric mean + + align:start position:0% +actually occurs at the geometric mean + + + align:start position:0% +actually occurs at the geometric mean +between the zero and the pole location + + align:start position:0% +between the zero and the pole location + + + align:start position:0% +between the zero and the pole location +remember that all of our networks were + + align:start position:0% +remember that all of our networks were + + + align:start position:0% +remember that all of our networks were +normalized to Unity for the location of + + align:start position:0% +normalized to Unity for the location of + + + align:start position:0% +normalized to Unity for the location of +the pole so all of our networks have the + + align:start position:0% +the pole so all of our networks have the + + + align:start position:0% +the pole so all of our networks have the +pole at this frequency at in the case of + + align:start position:0% +pole at this frequency at in the case of + + + align:start position:0% +pole at this frequency at in the case of +an alpha equals 5 the zero occurs a + + align:start position:0% +an alpha equals 5 the zero occurs a + + + align:start position:0% +an alpha equals 5 the zero occurs a +factor of Five Below that at this + + align:start position:0% +factor of Five Below that at this + + + align:start position:0% +factor of Five Below that at this +frequency we notice the maximum positive + + align:start position:0% +frequency we notice the maximum positive + + + align:start position:0% +frequency we notice the maximum positive +phase shift out of our Network at the + + align:start position:0% +phase shift out of our Network at the + + + align:start position:0% +phase shift out of our Network at the +geometric mean of those two frequencies + + align:start position:0% +geometric mean of those two frequencies + + + align:start position:0% +geometric mean of those two frequencies +and we get somewhere something over 40° + + align:start position:0% +and we get somewhere something over 40° + + + align:start position:0% +and we get somewhere something over 40° +of phase shift at the maximum a maximum + + align:start position:0% +of phase shift at the maximum a maximum + + + align:start position:0% +of phase shift at the maximum a maximum +when Alpha equals 5 uh similarly for + + align:start position:0% +when Alpha equals 5 uh similarly for + + + align:start position:0% +when Alpha equals 5 uh similarly for +Alpha equal 10 Alpha equals 20 we get up + + align:start position:0% +Alpha equal 10 Alpha equals 20 we get up + + + align:start position:0% +Alpha equal 10 Alpha equals 20 we get up +to something like 65 degrees of Maximum + + align:start position:0% +to something like 65 degrees of Maximum + + + align:start position:0% +to something like 65 degrees of Maximum +phase shift again occurring at the + + align:start position:0% +phase shift again occurring at the + + + align:start position:0% +phase shift again occurring at the +geometric mean of + + align:start position:0% +geometric mean of + + + align:start position:0% +geometric mean of +the zero and the pole in the case of of + + align:start position:0% +the zero and the pole in the case of of + + + align:start position:0% +the zero and the pole in the case of of +an alpha equals 20 here's the Z location + + align:start position:0% +an alpha equals 20 here's the Z location + + + align:start position:0% +an alpha equals 20 here's the Z location +for Alpha equals 20 at 05 on our + + align:start position:0% +for Alpha equals 20 at 05 on our + + + align:start position:0% +for Alpha equals 20 at 05 on our +frequency scale again here's the pole + + align:start position:0% +frequency scale again here's the pole + + + align:start position:0% +frequency scale again here's the pole +location the maximum positive phase + + align:start position:0% +location the maximum positive phase + + + align:start position:0% +location the maximum positive phase +shift from our lead Network occurs at + + align:start position:0% +shift from our lead Network occurs at + + + align:start position:0% +shift from our lead Network occurs at +the geometric mean of those two + + align:start position:0% +the geometric mean of those two + + + align:start position:0% +the geometric mean of those two +frequencies the important thing to that + + align:start position:0% +frequencies the important thing to that + + + align:start position:0% +frequencies the important thing to that +that we exploit in this sort of a + + align:start position:0% +that we exploit in this sort of a + + + align:start position:0% +that we exploit in this sort of a +transfer function or at least one of the + + align:start position:0% +transfer function or at least one of the + + + align:start position:0% +transfer function or at least one of the +things that we frequently exploit with + + align:start position:0% +things that we frequently exploit with + + + align:start position:0% +things that we frequently exploit with +this sort of a transfer function to + + align:start position:0% +this sort of a transfer function to + + + align:start position:0% +this sort of a transfer function to +improve the performance of a feedback + + align:start position:0% +improve the performance of a feedback + + + align:start position:0% +improve the performance of a feedback +system is that we begin to get positive + + align:start position:0% +system is that we begin to get positive + + + align:start position:0% +system is that we begin to get positive +phase shift + + align:start position:0% +phase shift + + + align:start position:0% +phase shift +before we have make an appreciable + + align:start position:0% +before we have make an appreciable + + + align:start position:0% +before we have make an appreciable +change in the magnitude characteristics + + align:start position:0% +change in the magnitude characteristics + + + align:start position:0% +change in the magnitude characteristics +if we look at our angle curve we notice + + align:start position:0% +if we look at our angle curve we notice + + + align:start position:0% +if we look at our angle curve we notice +that there's appreciable positive phase + + align:start position:0% +that there's appreciable positive phase + + + align:start position:0% +that there's appreciable positive phase +shift out of all three of the + + align:start position:0% +shift out of all three of the + + + align:start position:0% +shift out of all three of the +characteristics shown at the location of + + align:start position:0% +characteristics shown at the location of + + + align:start position:0% +characteristics shown at the location of +the zero here's the zero location for + + align:start position:0% +the zero here's the zero location for + + + align:start position:0% +the zero here's the zero location for +Alpha equals 20 and we actually have + + align:start position:0% +Alpha equals 20 and we actually have + + + align:start position:0% +Alpha equals 20 and we actually have +more than 40 degrees of positive phase + + align:start position:0% +more than 40 degrees of positive phase + + + align:start position:0% +more than 40 degrees of positive phase +shift at that frequency here's the zero + + align:start position:0% +shift at that frequency here's the zero + + + align:start position:0% +shift at that frequency here's the zero +location for Alpha equals 10 once again + + align:start position:0% +location for Alpha equals 10 once again + + + align:start position:0% +location for Alpha equals 10 once again +we have just about 40° of positive phase + + align:start position:0% +we have just about 40° of positive phase + + + align:start position:0% +we have just about 40° of positive phase +shift at that frequency here's the zero + + align:start position:0% +shift at that frequency here's the zero + + + align:start position:0% +shift at that frequency here's the zero +location for Alpha equals 5 and we have + + align:start position:0% +location for Alpha equals 5 and we have + + + align:start position:0% +location for Alpha equals 5 and we have +somewhere on the order of 35° of + + align:start position:0% +somewhere on the order of 35° of + + + align:start position:0% +somewhere on the order of 35° of +positive phase shift in that case so we + + align:start position:0% +positive phase shift in that case so we + + + align:start position:0% +positive phase shift in that case so we +begin to get a a very significant + + align:start position:0% +begin to get a a very significant + + + align:start position:0% +begin to get a a very significant +angular contrib contribution remember + + align:start position:0% +angular contrib contribution remember + + + align:start position:0% +angular contrib contribution remember +that we are interested in of times and + + align:start position:0% +that we are interested in of times and + + + align:start position:0% +that we are interested in of times and +getting phase margins and systems on the + + align:start position:0% +getting phase margins and systems on the + + + align:start position:0% +getting phase margins and systems on the +order of 45 degrees and so 45 degrees of + + align:start position:0% +order of 45 degrees and so 45 degrees of + + + align:start position:0% +order of 45 degrees and so 45 degrees of +positive phase shift can make a very + + align:start position:0% +positive phase shift can make a very + + + align:start position:0% +positive phase shift can make a very +important Improvement in the performance + + align:start position:0% +important Improvement in the performance + + + align:start position:0% +important Improvement in the performance +of a system here we have transfer + + align:start position:0% +of a system here we have transfer + + + align:start position:0% +of a system here we have transfer +characteristics that give us that sort + + align:start position:0% +characteristics that give us that sort + + + align:start position:0% +characteristics that give us that sort +of phase shift at the location of the + + align:start position:0% +of phase shift at the location of the + + + align:start position:0% +of phase shift at the location of the +zero well let's look back at the + + align:start position:0% +zero well let's look back at the + + + align:start position:0% +zero well let's look back at the +magnitude characteristics for a + + align:start position:0% + + + + align:start position:0% + +moment and again let's examine the + + align:start position:0% +moment and again let's examine the + + + align:start position:0% +moment and again let's examine the +magnitude characteristics at the + + align:start position:0% +magnitude characteristics at the + + + align:start position:0% +magnitude characteristics at the +location of the zero we notice that at + + align:start position:0% +location of the zero we notice that at + + + align:start position:0% +location of the zero we notice that at +the location of the zero there's only + + align:start position:0% +the location of the zero there's only + + + align:start position:0% +the location of the zero there's only +about a factor of + + align:start position:0% +about a factor of + + + align:start position:0% +about a factor of +1.4 increase in the magnitude here again + + align:start position:0% +1.4 increase in the magnitude here again + + + align:start position:0% +1.4 increase in the magnitude here again +is the zero location for Alpha equals 20 + + align:start position:0% +is the zero location for Alpha equals 20 + + + align:start position:0% +is the zero location for Alpha equals 20 +the magnitude is increased from its low + + align:start position:0% +the magnitude is increased from its low + + + align:start position:0% +the magnitude is increased from its low +frequency value by about a factor of 1.4 + + align:start position:0% +frequency value by about a factor of 1.4 + + + align:start position:0% +frequency value by about a factor of 1.4 +at the zero location similarly here + + align:start position:0% +at the zero location similarly here + + + align:start position:0% +at the zero location similarly here +here so the important part about the + + align:start position:0% +here so the important part about the + + + align:start position:0% +here so the important part about the +lead transfer function or at least one + + align:start position:0% +lead transfer function or at least one + + + align:start position:0% +lead transfer function or at least one +of the properties of the lead type + + align:start position:0% +of the properties of the lead type + + + align:start position:0% +of the properties of the lead type +transfer function that we're able to + + align:start position:0% +transfer function that we're able to + + + align:start position:0% +transfer function that we're able to +exploit is the fact that the phase shift + + align:start position:0% +exploit is the fact that the phase shift + + + align:start position:0% +exploit is the fact that the phase shift +becomes positive by a very significant + + align:start position:0% +becomes positive by a very significant + + + align:start position:0% +becomes positive by a very significant +amount at least in terms of improving + + align:start position:0% +amount at least in terms of improving + + + align:start position:0% +amount at least in terms of improving +the performance of a feedback system + + align:start position:0% +the performance of a feedback system + + + align:start position:0% +the performance of a feedback system +before there's much change in the + + align:start position:0% +before there's much change in the + + + align:start position:0% +before there's much change in the +magnitude characteristics and we can use + + align:start position:0% +magnitude characteristics and we can use + + + align:start position:0% +magnitude characteristics and we can use +that and the way we use it is as + + align:start position:0% +that and the way we use it is as + + + align:start position:0% +that and the way we use it is as +follows here's our magnitude + + align:start position:0% +follows here's our magnitude + + + align:start position:0% +follows here's our magnitude +characteristics for our uncompensated + + align:start position:0% +characteristics for our uncompensated + + + align:start position:0% +characteristics for our uncompensated +system let's locate the zero at least + + align:start position:0% +system let's locate the zero at least + + + align:start position:0% +system let's locate the zero at least +one of the things we can do and of + + align:start position:0% +one of the things we can do and of + + + align:start position:0% +one of the things we can do and of +course there are many ways of using + + align:start position:0% +course there are many ways of using + + + align:start position:0% +course there are many ways of using +these kinds of transfer functions to + + align:start position:0% +these kinds of transfer functions to + + + align:start position:0% +these kinds of transfer functions to +improve performance but one of the + + align:start position:0% +improve performance but one of the + + + align:start position:0% +improve performance but one of the +things we might do is locate the zero of + + align:start position:0% +things we might do is locate the zero of + + + align:start position:0% +things we might do is locate the zero of +the lead Network somewhere in the + + align:start position:0% +the lead Network somewhere in the + + + align:start position:0% +the lead Network somewhere in the +vicinity of crossover for the + + align:start position:0% +vicinity of crossover for the + + + align:start position:0% +vicinity of crossover for the +uncompensated system we might locate it + + align:start position:0% +uncompensated system we might locate it + + + align:start position:0% +uncompensated system we might locate it +somewhere out in here + + align:start position:0% + + + + align:start position:0% + +maybe like so so our magnitude + + align:start position:0% +maybe like so so our magnitude + + + align:start position:0% +maybe like so so our magnitude +characteristics would begin to go up in + + align:start position:0% +characteristics would begin to go up in + + + align:start position:0% +characteristics would begin to go up in +this + + align:start position:0% +this + + + align:start position:0% +this +region what we depend on is the fact + + align:start position:0% +region what we depend on is the fact + + + align:start position:0% +region what we depend on is the fact +that in this region before the magnitude + + align:start position:0% +that in this region before the magnitude + + + align:start position:0% +that in this region before the magnitude +has increased appreciably that would + + align:start position:0% +has increased appreciably that would + + + align:start position:0% +has increased appreciably that would +lead us to much higher crossover + + align:start position:0% +lead us to much higher crossover + + + align:start position:0% +lead us to much higher crossover +frequencies in in this vicinity we get + + align:start position:0% +frequencies in in this vicinity we get + + + align:start position:0% +frequencies in in this vicinity we get +appreciable positive phase shift out of + + align:start position:0% +appreciable positive phase shift out of + + + align:start position:0% +appreciable positive phase shift out of +our lead type transfer function and so + + align:start position:0% +our lead type transfer function and so + + + align:start position:0% +our lead type transfer function and so +the hope would be that the modification + + align:start position:0% +the hope would be that the modification + + + align:start position:0% +the hope would be that the modification +made to the angle is something like so + + align:start position:0% +made to the angle is something like so + + + align:start position:0% +made to the angle is something like so +eventually it drops off again but our + + align:start position:0% +eventually it drops off again but our + + + align:start position:0% +eventually it drops off again but our +hope is that we can get enough positive + + align:start position:0% +hope is that we can get enough positive + + + align:start position:0% +hope is that we can get enough positive +phase shift in the vicinity of crossover + + align:start position:0% +phase shift in the vicinity of crossover + + + align:start position:0% +phase shift in the vicinity of crossover +notice here crossovers increase just a + + align:start position:0% +notice here crossovers increase just a + + + align:start position:0% +notice here crossovers increase just a +little + + align:start position:0% +little + + + align:start position:0% +little +bit but the hope is that we've gotten + + align:start position:0% +bit but the hope is that we've gotten + + + align:start position:0% +bit but the hope is that we've gotten +appreciable positive phase shift in the + + align:start position:0% +appreciable positive phase shift in the + + + align:start position:0% +appreciable positive phase shift in the +vicinity of crossover so that we improve + + align:start position:0% +vicinity of crossover so that we improve + + + align:start position:0% +vicinity of crossover so that we improve +the phase margin of our system + + align:start position:0% +the phase margin of our system + + + align:start position:0% +the phase margin of our system +consequently its relative + + align:start position:0% +consequently its relative + + + align:start position:0% +consequently its relative +stability so that's one kind of + + align:start position:0% +stability so that's one kind of + + + align:start position:0% +stability so that's one kind of +modification we might like to make to + + align:start position:0% +modification we might like to make to + + + align:start position:0% +modification we might like to make to +the loop transmission of our feedback + + align:start position:0% +the loop transmission of our feedback + + + align:start position:0% +the loop transmission of our feedback +system + + align:start position:0% +system + + + align:start position:0% +system +a second possibility is to add a + + align:start position:0% +a second possibility is to add a + + + align:start position:0% +a second possibility is to add a +transfer function to the loop + + align:start position:0% +transfer function to the loop + + + align:start position:0% +transfer function to the loop +transmission that's called a lag type + + align:start position:0% +transmission that's called a lag type + + + align:start position:0% +transmission that's called a lag type +transfer + + align:start position:0% +transfer + + + align:start position:0% +transfer +function and here's the expression for a + + align:start position:0% +function and here's the expression for a + + + align:start position:0% +function and here's the expression for a +a lag transfer function again the output + + align:start position:0% +a lag transfer function again the output + + + align:start position:0% +a lag transfer function again the output +over the input is a combination this + + align:start position:0% +over the input is a combination this + + + align:start position:0% +over the input is a combination this +time of a pole at a relatively lower + + align:start position:0% +time of a pole at a relatively lower + + + align:start position:0% +time of a pole at a relatively lower +frequency than the zero we have this + + align:start position:0% +frequency than the zero we have this + + + align:start position:0% +frequency than the zero we have this +sort of a pole zero diagram for a lag + + align:start position:0% +sort of a pole zero diagram for a lag + + + align:start position:0% +sort of a pole zero diagram for a lag +kind of transfer function the pole + + align:start position:0% +kind of transfer function the pole + + + align:start position:0% +kind of transfer function the pole +occurs at a frequency one over Alpha to + + align:start position:0% +occurs at a frequency one over Alpha to + + + align:start position:0% +occurs at a frequency one over Alpha to +the zero at a frequency one over to + + align:start position:0% +the zero at a frequency one over to + + + align:start position:0% +the zero at a frequency one over to +again assuming Alpha is a number larger + + align:start position:0% +again assuming Alpha is a number larger + + + align:start position:0% +again assuming Alpha is a number larger +than one we get a Pole located at a + + align:start position:0% +than one we get a Pole located at a + + + align:start position:0% +than one we get a Pole located at a +lower frequency than the + + align:start position:0% +lower frequency than the + + + align:start position:0% +lower frequency than the +zero let's look at the characteristics + + align:start position:0% +zero let's look at the characteristics + + + align:start position:0% +zero let's look at the characteristics +of that sort of a network or first let's + + align:start position:0% +of that sort of a network or first let's + + + align:start position:0% +of that sort of a network or first let's +look at at how we might Implement that + + align:start position:0% +look at at how we might Implement that + + + align:start position:0% +look at at how we might Implement that +kind of a network and then let's look at + + align:start position:0% +kind of a network and then let's look at + + + align:start position:0% +kind of a network and then let's look at +its + + align:start position:0% + + + + align:start position:0% + +characteristics + + align:start position:0% + + + + align:start position:0% + +um here's the kind of a network that + + align:start position:0% +um here's the kind of a network that + + + align:start position:0% +um here's the kind of a network that +will give us a lag type transfer + + align:start position:0% +will give us a lag type transfer + + + align:start position:0% +will give us a lag type transfer +function uh we have again two resistors + + align:start position:0% +function uh we have again two resistors + + + align:start position:0% +function uh we have again two resistors +a single capacitor at sufficiently low + + align:start position:0% +a single capacitor at sufficiently low + + + align:start position:0% +a single capacitor at sufficiently low +frequencies where the capacitor is an + + align:start position:0% +frequencies where the capacitor is an + + + align:start position:0% +frequencies where the capacitor is an +open circuit uh the output over the + + align:start position:0% +open circuit uh the output over the + + + align:start position:0% +open circuit uh the output over the +input is simply one whereas at higher + + align:start position:0% +input is simply one whereas at higher + + + align:start position:0% +input is simply one whereas at higher +frequencies we get an attenuation R2 + + align:start position:0% +frequencies we get an attenuation R2 + + + align:start position:0% +frequencies we get an attenuation R2 +over R1 + R2 the net result is that we + + align:start position:0% +over R1 + R2 the net result is that we + + + align:start position:0% +over R1 + R2 the net result is that we +get an input to Output transfer function + + align:start position:0% +get an input to Output transfer function + + + align:start position:0% +get an input to Output transfer function +of the form I I showed on the Blackboard + + align:start position:0% +of the form I I showed on the Blackboard + + + align:start position:0% +of the form I I showed on the Blackboard +to s+1 over Alpha to s+ one Again by + + align:start position:0% +to s+1 over Alpha to s+ one Again by + + + align:start position:0% +to s+1 over Alpha to s+ one Again by +doing a little bit of arithmetic we're + + align:start position:0% +doing a little bit of arithmetic we're + + + align:start position:0% +doing a little bit of arithmetic we're +able to identify Alpha as being the + + align:start position:0% +able to identify Alpha as being the + + + align:start position:0% +able to identify Alpha as being the +reciprocal of the attenuation ratio uh + + align:start position:0% +reciprocal of the attenuation ratio uh + + + align:start position:0% +reciprocal of the attenuation ratio uh +Alpha is r1+ R2 over over R2 and to is + + align:start position:0% +Alpha is r1+ R2 over over R2 and to is + + + align:start position:0% +Alpha is r1+ R2 over over R2 and to is +simply R2 C for this particular Network + + align:start position:0% +simply R2 C for this particular Network + + + align:start position:0% +simply R2 C for this particular Network +topology as the name implies a lag + + align:start position:0% +topology as the name implies a lag + + + align:start position:0% +topology as the name implies a lag +Network gives us lagging or negative + + align:start position:0% +Network gives us lagging or negative + + + align:start position:0% +Network gives us lagging or negative +phase shift at all frequencies and let's + + align:start position:0% +phase shift at all frequencies and let's + + + align:start position:0% +phase shift at all frequencies and let's +look at the phase shift characteristics + + align:start position:0% +look at the phase shift characteristics + + + align:start position:0% +look at the phase shift characteristics +of a lag Network um for a lead Network + + align:start position:0% +of a lag Network um for a lead Network + + + align:start position:0% +of a lag Network um for a lead Network +we said that we have this sort of + + align:start position:0% +we said that we have this sort of + + + align:start position:0% +we said that we have this sort of +characteristic positive phase shift at + + align:start position:0% +characteristic positive phase shift at + + + align:start position:0% +characteristic positive phase shift at +all frequencies well the lag Network + + align:start position:0% +all frequencies well the lag Network + + + align:start position:0% +all frequencies well the lag Network +basically gives us characteristics like + + align:start position:0% +basically gives us characteristics like + + + align:start position:0% +basically gives us characteristics like +that it's a little bit confusing in this + + align:start position:0% +that it's a little bit confusing in this + + + align:start position:0% +that it's a little bit confusing in this +form we have a little problem with the + + align:start position:0% +form we have a little problem with the + + + align:start position:0% +form we have a little problem with the +axes but it emphasizes the Symmetry uh + + align:start position:0% +axes but it emphasizes the Symmetry uh + + + align:start position:0% +axes but it emphasizes the Symmetry uh +between a lead and a lag Network and is + + align:start position:0% +between a lead and a lag Network and is + + + align:start position:0% +between a lead and a lag Network and is +actually the correct form if we simply + + align:start position:0% +actually the correct form if we simply + + + align:start position:0% +actually the correct form if we simply +modify the the + + align:start position:0% +modify the the + + + align:start position:0% +modify the the +axes + + align:start position:0% +axes + + + align:start position:0% +axes +here is the actual + + align:start position:0% +here is the actual + + + align:start position:0% +here is the actual +angle characteristic for a lag + + align:start position:0% +angle characteristic for a lag + + + align:start position:0% +angle characteristic for a lag +Network again for several different + + align:start position:0% +Network again for several different + + + align:start position:0% +Network again for several different +values of of Alpha we have negative + + align:start position:0% +values of of Alpha we have negative + + + align:start position:0% +values of of Alpha we have negative +phase shift at at all frequencies of + + align:start position:0% +phase shift at at all frequencies of + + + align:start position:0% +phase shift at at all frequencies of +course running from 0 degrees down and + + align:start position:0% +course running from 0 degrees down and + + + align:start position:0% +course running from 0 degrees down and +so forth uh we have an for Alpha equals + + align:start position:0% +so forth uh we have an for Alpha equals + + + align:start position:0% +so forth uh we have an for Alpha equals +5 we hit a maximum negative phase shift + + align:start position:0% +5 we hit a maximum negative phase shift + + + align:start position:0% +5 we hit a maximum negative phase shift +of of again about minus 42 or 43 degrees + + align:start position:0% +of of again about minus 42 or 43 degrees + + + align:start position:0% +of of again about minus 42 or 43 degrees +the same amount as we got in the lead + + align:start position:0% +the same amount as we got in the lead + + + align:start position:0% +the same amount as we got in the lead +Network only the opposite sign and so + + align:start position:0% +Network only the opposite sign and so + + + align:start position:0% +Network only the opposite sign and so +forth so this is a completely identic + + align:start position:0% +forth so this is a completely identic + + + align:start position:0% +forth so this is a completely identic +curve except flipped over to that that + + align:start position:0% +curve except flipped over to that that + + + align:start position:0% +curve except flipped over to that that +we got for the lead network uh these are + + align:start position:0% +we got for the lead network uh these are + + + align:start position:0% +we got for the lead network uh these are +all normalized uh to a common pole + + align:start position:0% +all normalized uh to a common pole + + + align:start position:0% +all normalized uh to a common pole +location and uh we get + + align:start position:0% +location and uh we get + + + align:start position:0% +location and uh we get +the characteristics as we've we've shown + + align:start position:0% +the characteristics as we've we've shown + + + align:start position:0% +the characteristics as we've we've shown +them let's look at the corresponding + + align:start position:0% +them let's look at the corresponding + + + align:start position:0% +them let's look at the corresponding +magnitude + + align:start position:0% + + + + align:start position:0% + +characteristics and here are the + + align:start position:0% +characteristics and here are the + + + align:start position:0% +characteristics and here are the +magnitude characteristics uh for the lag + + align:start position:0% +magnitude characteristics uh for the lag + + + align:start position:0% +magnitude characteristics uh for the lag +net nwor again all normalized in this + + align:start position:0% +net nwor again all normalized in this + + + align:start position:0% +net nwor again all normalized in this +case to a pole location of one the zero + + align:start position:0% +case to a pole location of one the zero + + + align:start position:0% +case to a pole location of one the zero +comes out at progressively higher + + align:start position:0% +comes out at progressively higher + + + align:start position:0% +comes out at progressively higher +frequencies for increasing + + align:start position:0% +frequencies for increasing + + + align:start position:0% +frequencies for increasing +Alpha the way + + align:start position:0% +Alpha the way + + + align:start position:0% +Alpha the way +we exploit this network or at least one + + align:start position:0% +we exploit this network or at least one + + + align:start position:0% +we exploit this network or at least one +way that we can do it is as + + align:start position:0% +way that we can do it is as + + + align:start position:0% +way that we can do it is as +follows we try to use the lag Network to + + align:start position:0% +follows we try to use the lag Network to + + + align:start position:0% +follows we try to use the lag Network to +push down the magnitude over a range of + + align:start position:0% +push down the magnitude over a range of + + + align:start position:0% +push down the magnitude over a range of +frequencies in other words we locate the + + align:start position:0% +frequencies in other words we locate the + + + align:start position:0% +frequencies in other words we locate the +mag the lag type transfer function + + align:start position:0% +mag the lag type transfer function + + + align:start position:0% +mag the lag type transfer function +locate the pole and the zero somewhere + + align:start position:0% +locate the pole and the zero somewhere + + + align:start position:0% +locate the pole and the zero somewhere +below crossover and we recognize because + + align:start position:0% +below crossover and we recognize because + + + align:start position:0% +below crossover and we recognize because +of the attenuation characteristics + + align:start position:0% +of the attenuation characteristics + + + align:start position:0% +of the attenuation characteristics +associated with the lag type transfer + + align:start position:0% +associated with the lag type transfer + + + align:start position:0% +associated with the lag type transfer +function that will push the magnitude + + align:start position:0% +function that will push the magnitude + + + align:start position:0% +function that will push the magnitude +curve + + align:start position:0% +curve + + + align:start position:0% +curve +down but not at DC it doesn't have the + + align:start position:0% +down but not at DC it doesn't have the + + + align:start position:0% +down but not at DC it doesn't have the +same effect as as simply lowering the a + + align:start position:0% +same effect as as simply lowering the a + + + align:start position:0% +same effect as as simply lowering the a +fnot product it pushes the magnitude + + align:start position:0% +fnot product it pushes the magnitude + + + align:start position:0% +fnot product it pushes the magnitude +down at frequencies beyond the pole + + align:start position:0% +down at frequencies beyond the pole + + + align:start position:0% +down at frequencies beyond the pole +associated with the lag type transfer + + align:start position:0% +associated with the lag type transfer + + + align:start position:0% +associated with the lag type transfer +function so the modification that we + + align:start position:0% +function so the modification that we + + + align:start position:0% +function so the modification that we +might make in the case of lag is to + + align:start position:0% +might make in the case of lag is to + + + align:start position:0% +might make in the case of lag is to +possibly put the pole in here the curve + + align:start position:0% +possibly put the pole in here the curve + + + align:start position:0% +possibly put the pole in here the curve +would drop down we then add the zero and + + align:start position:0% +would drop down we then add the zero and + + + align:start position:0% +would drop down we then add the zero and +we + + align:start position:0% + + + + align:start position:0% + +eventually end up with our compensated + + align:start position:0% +eventually end up with our compensated + + + align:start position:0% +eventually end up with our compensated +curve going parallel to the original + + align:start position:0% +curve going parallel to the original + + + align:start position:0% +curve going parallel to the original +curve what happens to the angle under + + align:start position:0% +curve what happens to the angle under + + + align:start position:0% +curve what happens to the angle under +those conditions well here's the pole + + align:start position:0% +those conditions well here's the pole + + + align:start position:0% +those conditions well here's the pole +and here's the zero associated with our + + align:start position:0% +and here's the zero associated with our + + + align:start position:0% +and here's the zero associated with our +lag transfer function and we recall from + + align:start position:0% +lag transfer function and we recall from + + + align:start position:0% +lag transfer function and we recall from +the plot of the angle characteristics of + + align:start position:0% +the plot of the angle characteristics of + + + align:start position:0% +the plot of the angle characteristics of +the lag function and the lead function + + align:start position:0% +the lag function and the lead function + + + align:start position:0% +the lag function and the lead function +for that matter that the most profound + + align:start position:0% +for that matter that the most profound + + + align:start position:0% +for that matter that the most profound +effect on the angle occurs over a + + align:start position:0% +effect on the angle occurs over a + + + align:start position:0% +effect on the angle occurs over a +frequency range between the two + + align:start position:0% +frequency range between the two + + + align:start position:0% +frequency range between the two +singularities between the pole and the + + align:start position:0% +singularities between the pole and the + + + align:start position:0% +singularities between the pole and the +zero associated with the transfer + + align:start position:0% +zero associated with the transfer + + + align:start position:0% +zero associated with the transfer +function so here in the case of of a lag + + align:start position:0% +function so here in the case of of a lag + + + align:start position:0% +function so here in the case of of a lag +Network put in possibly in this range + + align:start position:0% +Network put in possibly in this range + + + align:start position:0% +Network put in possibly in this range +we'd anticipate that we'd put a negative + + align:start position:0% +we'd anticipate that we'd put a negative + + + align:start position:0% +we'd anticipate that we'd put a negative +lump in + + align:start position:0% +lump in + + + align:start position:0% +lump in +the phase characteristics we do + + align:start position:0% +the phase characteristics we do + + + align:start position:0% +the phase characteristics we do +something like + + align:start position:0% +something like + + + align:start position:0% +something like +this but but the hope is that we locate + + align:start position:0% +this but but the hope is that we locate + + + align:start position:0% +this but but the hope is that we locate +the lag Network so that the angle has + + align:start position:0% +the lag Network so that the angle has + + + align:start position:0% +the lag Network so that the angle has +very nearly returned to its + + align:start position:0% +very nearly returned to its + + + align:start position:0% +very nearly returned to its +uncompensated value before crossover + + align:start position:0% +uncompensated value before crossover + + + align:start position:0% +uncompensated value before crossover +notice that with the lag Network we've + + align:start position:0% +notice that with the lag Network we've + + + align:start position:0% +notice that with the lag Network we've +lowered + + align:start position:0% +lowered + + + align:start position:0% +lowered +crossover back to this frequency and if + + align:start position:0% +crossover back to this frequency and if + + + align:start position:0% +crossover back to this frequency and if +we can locate the lag Network at a low + + align:start position:0% +we can locate the lag Network at a low + + + align:start position:0% +we can locate the lag Network at a low +enough frequency we can ensure that the + + align:start position:0% +enough frequency we can ensure that the + + + align:start position:0% +enough frequency we can ensure that the +residual negative phase shift associated + + align:start position:0% +residual negative phase shift associated + + + align:start position:0% +residual negative phase shift associated +with the lag network has become very + + align:start position:0% +with the lag network has become very + + + align:start position:0% +with the lag network has become very +small and as I've shown in this + + align:start position:0% +small and as I've shown in this + + + align:start position:0% +small and as I've shown in this +Construction we end up improving the + + align:start position:0% +Construction we end up improving the + + + align:start position:0% +Construction we end up improving the +phase margin of the system from its + + align:start position:0% +phase margin of the system from its + + + align:start position:0% +phase margin of the system from its +original uncompensated value to this + + align:start position:0% +original uncompensated value to this + + + align:start position:0% +original uncompensated value to this +value by simply pushing down the + + align:start position:0% +value by simply pushing down the + + + align:start position:0% +value by simply pushing down the +magnitude curve causing the crossover + + align:start position:0% +magnitude curve causing the crossover + + + align:start position:0% +magnitude curve causing the crossover +frequency to lower + + align:start position:0% +frequency to lower + + + align:start position:0% +frequency to lower +and without having if we've located + + align:start position:0% +and without having if we've located + + + align:start position:0% +and without having if we've located +things properly so we don't have a great + + align:start position:0% +things properly so we don't have a great + + + align:start position:0% +things properly so we don't have a great +deal of residual negative phase shift + + align:start position:0% +deal of residual negative phase shift + + + align:start position:0% +deal of residual negative phase shift +from the lag Network we improve the + + align:start position:0% +from the lag Network we improve the + + + align:start position:0% +from the lag Network we improve the +phase margin of the system in that way + + align:start position:0% +phase margin of the system in that way + + + align:start position:0% +phase margin of the system in that way +while we've lowered desensitivity over a + + align:start position:0% +while we've lowered desensitivity over a + + + align:start position:0% +while we've lowered desensitivity over a +range of frequencies here we haven't + + align:start position:0% +range of frequencies here we haven't + + + align:start position:0% +range of frequencies here we haven't +located lower desensitivity back in this + + align:start position:0% +located lower desensitivity back in this + + + align:start position:0% +located lower desensitivity back in this +region so we're able to use the lag + + align:start position:0% +region so we're able to use the lag + + + align:start position:0% +region so we're able to use the lag +Network to improve our desensi or + + align:start position:0% +Network to improve our desensi or + + + align:start position:0% +Network to improve our desensi or +maintain our desensitivity at lower + + align:start position:0% +maintain our desensitivity at lower + + + align:start position:0% +maintain our desensitivity at lower +frequencies and yet improve the + + align:start position:0% +frequencies and yet improve the + + + align:start position:0% +frequencies and yet improve the +stability of the system and so that's + + align:start position:0% +stability of the system and so that's + + + align:start position:0% +stability of the system and so that's +the way we typically use a lag type + + align:start position:0% +the way we typically use a lag type + + + align:start position:0% +the way we typically use a lag type +transfer function to improve the + + align:start position:0% +transfer function to improve the + + + align:start position:0% +transfer function to improve the +performance of a feedback system one + + align:start position:0% +performance of a feedback system one + + + align:start position:0% +performance of a feedback system one +final thing that's useful for design + + align:start position:0% +final thing that's useful for design + + + align:start position:0% +final thing that's useful for design +purposes in in these when we use these + + align:start position:0% +purposes in in these when we use these + + + align:start position:0% +purposes in in these when we use these +kinds of networks is the maximum phase + + align:start position:0% +kinds of networks is the maximum phase + + + align:start position:0% +kinds of networks is the maximum phase +shift that we get out of a network or a + + align:start position:0% +shift that we get out of a network or a + + + align:start position:0% +shift that we get out of a network or a +trans transfer function uh the maximum + + align:start position:0% +trans transfer function uh the maximum + + + align:start position:0% +trans transfer function uh the maximum +angle associated with either a lead or a + + align:start position:0% +angle associated with either a lead or a + + + align:start position:0% +angle associated with either a lead or a +lag transfer function the only + + align:start position:0% +lag transfer function the only + + + align:start position:0% +lag transfer function the only +difference is the sign of course we + + align:start position:0% +difference is the sign of course we + + + align:start position:0% +difference is the sign of course we +notice that for a lead type transfer + + align:start position:0% +notice that for a lead type transfer + + + align:start position:0% +notice that for a lead type transfer +function we get positive phase shift for + + align:start position:0% +function we get positive phase shift for + + + align:start position:0% +function we get positive phase shift for +a lag type we get Negative phase shift + + align:start position:0% +a lag type we get Negative phase shift + + + align:start position:0% +a lag type we get Negative phase shift +the maximum angle is simply the arc sign + + align:start position:0% +the maximum angle is simply the arc sign + + + align:start position:0% +the maximum angle is simply the arc sign +of alpha minus one over Alpha + one for + + align:start position:0% +of alpha minus one over Alpha + one for + + + align:start position:0% +of alpha minus one over Alpha + one for +either the lead or the lag type transfer + + align:start position:0% +either the lead or the lag type transfer + + + align:start position:0% +either the lead or the lag type transfer +function we also recognize that we have + + align:start position:0% +function we also recognize that we have + + + align:start position:0% +function we also recognize that we have +to have more degrees of freedom than + + align:start position:0% +to have more degrees of freedom than + + + align:start position:0% +to have more degrees of freedom than +simply adding these transfer fun + + align:start position:0% +simply adding these transfer fun + + + align:start position:0% +simply adding these transfer fun +functions very frequently we combine a + + align:start position:0% +functions very frequently we combine a + + + align:start position:0% +functions very frequently we combine a +lead or a lag type transfer function + + align:start position:0% +lead or a lag type transfer function + + + align:start position:0% +lead or a lag type transfer function +with a modification to the a fnot + + align:start position:0% +with a modification to the a fnot + + + align:start position:0% +with a modification to the a fnot +product and that combination is a very + + align:start position:0% +product and that combination is a very + + + align:start position:0% +product and that combination is a very +very powerful way to improve or to + + align:start position:0% +very powerful way to improve or to + + + align:start position:0% +very powerful way to improve or to +modify the performance of a feedback + + align:start position:0% +modify the performance of a feedback + + + align:start position:0% +modify the performance of a feedback +system next time I'd like to look at how + + align:start position:0% +system next time I'd like to look at how + + + align:start position:0% +system next time I'd like to look at how +we use these ideas to compensate an + + align:start position:0% +we use these ideas to compensate an + + + align:start position:0% +we use these ideas to compensate an +actual feedback system we'll do a + + align:start position:0% +actual feedback system we'll do a + + + align:start position:0% +actual feedback system we'll do a +demonstration where we take an amplifier + + align:start position:0% +demonstration where we take an amplifier + + + align:start position:0% +demonstration where we take an amplifier +and with given characteristics and see + + align:start position:0% +and with given characteristics and see + + + align:start position:0% +and with given characteristics and see +how we use these kinds of Concepts to + + align:start position:0% +how we use these kinds of Concepts to + + + align:start position:0% +how we use these kinds of Concepts to +improve the performance of the of the + + align:start position:0% +improve the performance of the of the + + + align:start position:0% +improve the performance of the of the +feedback system that includes that + + align:start position:0% +feedback system that includes that + + + align:start position:0% +feedback system that includes that +amplifier thank you \ No newline at end of file diff --git a/C_pgH5QhIZ8.txt b/C_pgH5QhIZ8.txt new file mode 100644 index 0000000000000000000000000000000000000000..fa84f85144de1f28b3a4e9c2eccfef4f09d113b8 --- /dev/null +++ b/C_pgH5QhIZ8.txt @@ -0,0 +1,331 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +view additional materials from hundreds + + align:start position:0% +view additional materials from hundreds + + + align:start position:0% +view additional materials from hundreds +of MIT courses visit MIT opencourseware + + align:start position:0% +of MIT courses visit MIT opencourseware + + + align:start position:0% +of MIT courses visit MIT opencourseware +at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu so we have a class car + + align:start position:0% +ocw.mit.edu so we have a class car + + + align:start position:0% +ocw.mit.edu so we have a class car +here object as as usual the init method + + align:start position:0% +here object as as usual the init method + + + align:start position:0% +here object as as usual the init method +here takes in self as usual a w and a d + + align:start position:0% +here takes in self as usual a w and a d + + + align:start position:0% +here takes in self as usual a w and a d +so uh so a car gets initialized with two + + align:start position:0% +so uh so a car gets initialized with two + + + align:start position:0% +so uh so a car gets initialized with two +uh + + align:start position:0% +uh + + + align:start position:0% +uh +parameters and we assign the wheels data + + align:start position:0% +parameters and we assign the wheels data + + + align:start position:0% +parameters and we assign the wheels data +attribute to the first one and the do's + + align:start position:0% +attribute to the first one and the do's + + + align:start position:0% +attribute to the first one and the do's +data attribute to the second one and + + align:start position:0% +data attribute to the second one and + + + align:start position:0% +data attribute to the second one and +then we're going to also assign a color + + align:start position:0% +then we're going to also assign a color + + + align:start position:0% +then we're going to also assign a color +data attribute um to be the empty string + + align:start position:0% +data attribute um to be the empty string + + + align:start position:0% +data attribute um to be the empty string +so I'm giving you four choices here and + + align:start position:0% +so I'm giving you four choices here and + + + align:start position:0% +so I'm giving you four choices here and +the question says which of the above is + + align:start position:0% +the question says which of the above is + + + align:start position:0% +the question says which of the above is +a getter method for the number of Wheels + + align:start position:0% +a getter method for the number of Wheels + + + align:start position:0% +a getter method for the number of Wheels +okay so getter + + align:start position:0% +okay so getter + + + align:start position:0% +okay so getter +method is something that's going to get + + align:start position:0% +method is something that's going to get + + + align:start position:0% +method is something that's going to get +a data + + align:start position:0% +a data + + + align:start position:0% +a data +attribute a method is really just a + + align:start position:0% +attribute a method is really just a + + + align:start position:0% +attribute a method is really just a +function so of course we're going to + + align:start position:0% +function so of course we're going to + + + align:start position:0% +function so of course we're going to +have DF get wheels is a good name for it + + align:start position:0% +have DF get wheels is a good name for it + + + align:start position:0% +have DF get wheels is a good name for it +since it's a method for this class we + + align:start position:0% +since it's a method for this class we + + + align:start position:0% +since it's a method for this class we +have to have self in the par parameters + + align:start position:0% +have to have self in the par parameters + + + align:start position:0% +have to have self in the par parameters +so we know it's going to be between c + + align:start position:0% +so we know it's going to be between c + + + align:start position:0% +so we know it's going to be between c +and + + align:start position:0% +and + + + align:start position:0% +and +d and so then what are we going to + + align:start position:0% +d and so then what are we going to + + + align:start position:0% +d and so then what are we going to +return the first one is going to return + + align:start position:0% +return the first one is going to return + + + align:start position:0% +return the first one is going to return +Wheels which in this particular case is + + align:start position:0% +Wheels which in this particular case is + + + align:start position:0% +Wheels which in this particular case is +just going to be a variable that we + + align:start position:0% +just going to be a variable that we + + + align:start position:0% +just going to be a variable that we +haven't defined but it's a variable a + + align:start position:0% +haven't defined but it's a variable a + + + align:start position:0% +haven't defined but it's a variable a +getter return returns a data attribute + + align:start position:0% +getter return returns a data attribute + + + align:start position:0% +getter return returns a data attribute +of a particular instance so we actually + + align:start position:0% +of a particular instance so we actually + + + align:start position:0% +of a particular instance so we actually +have to say self dot if we want to + + align:start position:0% +have to say self dot if we want to + + + align:start position:0% +have to say self dot if we want to +return a data attribute of an instance + + align:start position:0% +return a data attribute of an instance + + + align:start position:0% +return a data attribute of an instance +as opposed to just a a regular variable + + align:start position:0% +as opposed to just a a regular variable + + + align:start position:0% +as opposed to just a a regular variable +so the correct answer is D great job \ No newline at end of file diff --git a/DkOgvZywshI.txt b/DkOgvZywshI.txt new file mode 100644 index 0000000000000000000000000000000000000000..ea316e98a285527625b236bc838b89ee14fec8a2 --- /dev/null +++ b/DkOgvZywshI.txt @@ -0,0 +1,803 @@ +align:start position:0% + +most frequently-used Odie's solver + + align:start position:0% +most frequently-used Odie's solver + + + align:start position:0% +most frequently-used Odie's solver +MATLAB and Simulink is OD 4/5 it's based + + align:start position:0% +MATLAB and Simulink is OD 4/5 it's based + + + align:start position:0% +MATLAB and Simulink is OD 4/5 it's based +on method published by British + + align:start position:0% +on method published by British + + + align:start position:0% +on method published by British +mathematicians junior Normand and PJ + + align:start position:0% +mathematicians junior Normand and PJ + + + align:start position:0% +mathematicians junior Normand and PJ +Prince in 1980 the basic method is order + + align:start position:0% +Prince in 1980 the basic method is order + + + align:start position:0% +Prince in 1980 the basic method is order +5 the error correction uses a companion + + align:start position:0% +5 the error correction uses a companion + + + align:start position:0% +5 the error correction uses a companion +order for method the first slope of TN + + align:start position:0% +order for method the first slope of TN + + + align:start position:0% +order for method the first slope of TN +is first same as last left over from the + + align:start position:0% +is first same as last left over from the + + + align:start position:0% +is first same as last left over from the +previous successful step then there are + + align:start position:0% +previous successful step then there are + + + align:start position:0% +previous successful step then there are +five more slopes from function values at + + align:start position:0% +five more slopes from function values at + + + align:start position:0% +five more slopes from function values at +50 H 3/10 H 4/5 h89 H and then at TN + + align:start position:0% +50 H 3/10 H 4/5 h89 H and then at TN + + + align:start position:0% +50 H 3/10 H 4/5 h89 H and then at TN +plus 1 these six slopes linear + + align:start position:0% +plus 1 these six slopes linear + + + align:start position:0% +plus 1 these six slopes linear +combinations of them are used to produce + + align:start position:0% +combinations of them are used to produce + + + align:start position:0% +combinations of them are used to produce +yn plus 1 the function value the + + align:start position:0% +yn plus 1 the function value the + + + align:start position:0% +yn plus 1 the function value the +function is evaluated at TN plus 1 and + + align:start position:0% +function is evaluated at TN plus 1 and + + + align:start position:0% +function is evaluated at TN plus 1 and +yn plus 1 to get a seventh slope and + + align:start position:0% +yn plus 1 to get a seventh slope and + + + align:start position:0% +yn plus 1 to get a seventh slope and +then linear combinations of these are + + align:start position:0% +then linear combinations of these are + + + align:start position:0% +then linear combinations of these are +used to produce the error estimate again + + align:start position:0% +used to produce the error estimate again + + + align:start position:0% +used to produce the error estimate again +if the error estimate is less than the + + align:start position:0% +if the error estimate is less than the + + + align:start position:0% +if the error estimate is less than the +specified accuracy requirement the step + + align:start position:0% +specified accuracy requirement the step + + + align:start position:0% +specified accuracy requirement the step +is successful and then that that error + + align:start position:0% +is successful and then that that error + + + align:start position:0% +is successful and then that that error +estimate is used to get the next step + + align:start position:0% +estimate is used to get the next step + + + align:start position:0% +estimate is used to get the next step +size if the air is too big the step is + + align:start position:0% +size if the air is too big the step is + + + align:start position:0% +size if the air is too big the step is +unsuccessful and that their estimate is + + align:start position:0% +unsuccessful and that their estimate is + + + align:start position:0% +unsuccessful and that their estimate is +used to get the used to get the step + + align:start position:0% +used to get the used to get the step + + + align:start position:0% +used to get the used to get the step +size to do the step over again we want + + align:start position:0% +size to do the step over again we want + + + align:start position:0% +size to do the step over again we want +to see the actual coefficients they're + + align:start position:0% +to see the actual coefficients they're + + + align:start position:0% +to see the actual coefficients they're +used you can go into the code for OD 4/5 + + align:start position:0% +used you can go into the code for OD 4/5 + + + align:start position:0% +used you can go into the code for OD 4/5 +there's a table with the coefficients or + + align:start position:0% +there's a table with the coefficients or + + + align:start position:0% +there's a table with the coefficients or +you can go to the Wikipedia page for the + + align:start position:0% +you can go to the Wikipedia page for the + + + align:start position:0% +you can go to the Wikipedia page for the +dormant Prince method and there's the + + align:start position:0% +dormant Prince method and there's the + + + align:start position:0% +dormant Prince method and there's the +same coefficients as an aside here is an + + align:start position:0% +same coefficients as an aside here is an + + + align:start position:0% +same coefficients as an aside here is an +interesting fact about higher order + + align:start position:0% +interesting fact about higher order + + + align:start position:0% +interesting fact about higher order +runge-kutta methods classical + + align:start position:0% +runge-kutta methods classical + + + align:start position:0% +runge-kutta methods classical +runge-kutta required for function + + align:start position:0% +runge-kutta required for function + + + align:start position:0% +runge-kutta required for function +evaluation + + align:start position:0% +evaluation + + + align:start position:0% +evaluation +per step to get order for doorman Prince + + align:start position:0% +per step to get order for doorman Prince + + + align:start position:0% +per step to get order for doorman Prince +requires six function evaluations per + + align:start position:0% +requires six function evaluations per + + + align:start position:0% +requires six function evaluations per +step to get order five you can't get + + align:start position:0% +step to get order five you can't get + + + align:start position:0% +step to get order five you can't get +order five with just five function + + align:start position:0% +order five with just five function + + + align:start position:0% +order five with just five function +evaluations and then as we try it if we + + align:start position:0% +evaluations and then as we try it if we + + + align:start position:0% +evaluations and then as we try it if we +were to try and achieve higher order it + + align:start position:0% +were to try and achieve higher order it + + + align:start position:0% +were to try and achieve higher order it +would take even more function + + align:start position:0% +would take even more function + + + align:start position:0% +would take even more function +evaluations per step let's use OD 45 to + + align:start position:0% +evaluations per step let's use OD 45 to + + + align:start position:0% +evaluations per step let's use OD 45 to +compute thee to the T Y prime is equal + + align:start position:0% +compute thee to the T Y prime is equal + + + align:start position:0% +compute thee to the T Y prime is equal +to Y we can ask for output by supplying + + align:start position:0% +to Y we can ask for output by supplying + + + align:start position:0% +to Y we can ask for output by supplying +an argument called T span zero and steps + + align:start position:0% +an argument called T span zero and steps + + + align:start position:0% +an argument called T span zero and steps +of 0.1 to 1 if we supply that as the + + align:start position:0% +of 0.1 to 1 if we supply that as the + + + align:start position:0% +of 0.1 to 1 if we supply that as the +input argument to solve this + + align:start position:0% +input argument to solve this + + + align:start position:0% +input argument to solve this +differential equation and get the output + + align:start position:0% +differential equation and get the output + + + align:start position:0% +differential equation and get the output +at those points that we get that back as + + align:start position:0% +at those points that we get that back as + + + align:start position:0% +at those points that we get that back as +the output and now here's the + + align:start position:0% +the output and now here's the + + + align:start position:0% +the output and now here's the +approximation of a solution to that + + align:start position:0% +approximation of a solution to that + + + align:start position:0% +approximation of a solution to that +differential equation at that of those + + align:start position:0% +differential equation at that of those + + + align:start position:0% +differential equation at that of those +points if we plot it here's the solution + + align:start position:0% +points if we plot it here's the solution + + + align:start position:0% +points if we plot it here's the solution +at those points and to see how accurate + + align:start position:0% +at those points and to see how accurate + + + align:start position:0% +at those points and to see how accurate +it is we see that we're actually getting + + align:start position:0% +it is we see that we're actually getting + + + align:start position:0% +it is we see that we're actually getting +this result to nine in digits OD e 45 is + + align:start position:0% +this result to nine in digits OD e 45 is + + + align:start position:0% +this result to nine in digits OD e 45 is +very accurate let's look at step size + + align:start position:0% +very accurate let's look at step size + + + align:start position:0% +very accurate let's look at step size +choice on our problem with near + + align:start position:0% +choice on our problem with near + + + align:start position:0% +choice on our problem with near +singularity is a quarter y naught is + + align:start position:0% +singularity is a quarter y naught is + + + align:start position:0% +singularity is a quarter y naught is +close to 16 the differential equation is + + align:start position:0% +close to 16 the differential equation is + + + align:start position:0% +close to 16 the differential equation is +y prime is 2 a minus T y squared we let + + align:start position:0% +y prime is 2 a minus T y squared we let + + + align:start position:0% +y prime is 2 a minus T y squared we let +OD 45 choose its own step size by + + align:start position:0% +OD 45 choose its own step size by + + + align:start position:0% +OD 45 choose its own step size by +indicating we just want to indicate from + + align:start position:0% +indicating we just want to indicate from + + + align:start position:0% +indicating we just want to indicate from +integrate from 0 to 1 we capture the + + align:start position:0% +integrate from 0 to 1 we capture the + + + align:start position:0% +integrate from 0 to 1 we capture the +output in T and Y and plot it + + align:start position:0% + + + + align:start position:0% + +now here there's a lot of points here + + align:start position:0% +now here there's a lot of points here + + + align:start position:0% +now here there's a lot of points here +but this is misleading because OD e 45 + + align:start position:0% +but this is misleading because OD e 45 + + + align:start position:0% +but this is misleading because OD e 45 +is using by default is using the refine + + align:start position:0% +is using by default is using the refine + + + align:start position:0% +is using by default is using the refine +option it's only evaluated actually + + align:start position:0% +option it's only evaluated actually + + + align:start position:0% +option it's only evaluated actually +evaluating the function at every 4th one + + align:start position:0% +evaluating the function at every 4th one + + + align:start position:0% +evaluating the function at every 4th one +of these points and then using the + + align:start position:0% +of these points and then using the + + + align:start position:0% +of these points and then using the +interpolant to fill in in between so we + + align:start position:0% +interpolant to fill in in between so we + + + align:start position:0% +interpolant to fill in in between so we +actually need a little different plot + + align:start position:0% +actually need a little different plot + + + align:start position:0% +actually need a little different plot +here this plot shows a little better + + align:start position:0% +here this plot shows a little better + + + align:start position:0% +here this plot shows a little better +what's going on the big dots are the + + align:start position:0% +what's going on the big dots are the + + + align:start position:0% +what's going on the big dots are the +points that OD 45 chose to evaluate the + + align:start position:0% +points that OD 45 chose to evaluate the + + + align:start position:0% +points that OD 45 chose to evaluate the +the differential equation and the little + + align:start position:0% +the differential equation and the little + + + align:start position:0% +the differential equation and the little +dots are filled in with interpolant so + + align:start position:0% +dots are filled in with interpolant so + + + align:start position:0% +dots are filled in with interpolant so +the big dots are every fourth point and + + align:start position:0% +the big dots are every fourth point and + + + align:start position:0% +the big dots are every fourth point and +the refine option says that the big dots + + align:start position:0% +the refine option says that the big dots + + + align:start position:0% +the refine option says that the big dots +are too far apart and we need to fill it + + align:start position:0% +are too far apart and we need to fill it + + + align:start position:0% +are too far apart and we need to fill it +in with the interpolant so this is the + + align:start position:0% +in with the interpolant so this is the + + + align:start position:0% +in with the interpolant so this is the +continuous interpolate in action the big + + align:start position:0% +continuous interpolate in action the big + + + align:start position:0% +continuous interpolate in action the big +dots are concentrated are more closely + + align:start position:0% +dots are concentrated are more closely + + + align:start position:0% +dots are concentrated are more closely +concentrated as we have to go around the + + align:start position:0% +concentrated as we have to go around the + + + align:start position:0% +concentrated as we have to go around the +curve and then as we get farther away + + align:start position:0% +curve and then as we get farther away + + + align:start position:0% +curve and then as we get farther away +from the singularity the step size + + align:start position:0% +from the singularity the step size + + + align:start position:0% +from the singularity the step size +increases so this shows the high + + align:start position:0% +increases so this shows the high + + + align:start position:0% +increases so this shows the high +accuracy of ode45 and the automatic step + + align:start position:0% +accuracy of ode45 and the automatic step + + + align:start position:0% +accuracy of ode45 and the automatic step +size choice in action here's an exercise + + align:start position:0% +size choice in action here's an exercise + + + align:start position:0% +size choice in action here's an exercise +compare OD e23 and OD 45 by using each + + align:start position:0% +compare OD e23 and OD 45 by using each + + + align:start position:0% +compare OD e23 and OD 45 by using each +of them to keep you PI the integral four + + align:start position:0% +of them to keep you PI the integral four + + + align:start position:0% +of them to keep you PI the integral four +over one plus t-squared from zero to one + + align:start position:0% +over one plus t-squared from zero to one + + + align:start position:0% +over one plus t-squared from zero to one +is pi you can express that as a + + align:start position:0% +is pi you can express that as a + + + align:start position:0% +is pi you can express that as a +differential equation use each of the + + align:start position:0% +differential equation use each of the + + + align:start position:0% +differential equation use each of the +routines to integrate that differential + + align:start position:0% +routines to integrate that differential + + + align:start position:0% +routines to integrate that differential +equation and see how close they get to + + align:start position:0% +equation and see how close they get to + + + align:start position:0% +equation and see how close they get to +compute + + align:start position:0% +compute + + + align:start position:0% +compute +in PI \ No newline at end of file diff --git a/EMyRV3H4Vf4.txt b/EMyRV3H4Vf4.txt new file mode 100644 index 0000000000000000000000000000000000000000..a1e82945ae218d9fc2e514588596f95e6b6e07ad --- /dev/null +++ b/EMyRV3H4Vf4.txt @@ -0,0 +1,203 @@ +align:start position:0% + +if a student comes to me and uh they're + + align:start position:0% +if a student comes to me and uh they're + + + align:start position:0% +if a student comes to me and uh they're +getting really stuck and solving their + + align:start position:0% +getting really stuck and solving their + + + align:start position:0% +getting really stuck and solving their +problem then I would suggest to them uh + + align:start position:0% +problem then I would suggest to them uh + + + align:start position:0% +problem then I would suggest to them uh +collaborate more uh but I find + + align:start position:0% +collaborate more uh but I find + + + align:start position:0% +collaborate more uh but I find +collaboration is really the best way + + align:start position:0% +collaboration is really the best way + + + align:start position:0% +collaboration is really the best way +both to do brainstorming because you get + + align:start position:0% +both to do brainstorming because you get + + + align:start position:0% +both to do brainstorming because you get +very quick feedback uh in ideas but also + + align:start position:0% +very quick feedback uh in ideas but also + + + align:start position:0% +very quick feedback uh in ideas but also +you get this kind of compounding effect + + align:start position:0% +you get this kind of compounding effect + + + align:start position:0% +you get this kind of compounding effect +where your ideas Inspire the maybe more + + align:start position:0% +where your ideas Inspire the maybe more + + + align:start position:0% +where your ideas Inspire the maybe more +experienced person to have some other + + align:start position:0% +experienced person to have some other + + + align:start position:0% +experienced person to have some other +idea and oh that reminds me of this + + align:start position:0% +idea and oh that reminds me of this + + + align:start position:0% +idea and oh that reminds me of this +other paper maybe you should go look at + + align:start position:0% +other paper maybe you should go look at + + + align:start position:0% +other paper maybe you should go look at +this um and so just talking with people + + align:start position:0% +this um and so just talking with people + + + align:start position:0% +this um and so just talking with people +about your problem makes a huge impact + + align:start position:0% +about your problem makes a huge impact + + + align:start position:0% +about your problem makes a huge impact +and maybe they join in and help solve it + + align:start position:0% +and maybe they join in and help solve it + + + align:start position:0% +and maybe they join in and help solve it +or maybe they just give one idea that + + align:start position:0% +or maybe they just give one idea that + + + align:start position:0% +or maybe they just give one idea that +leads you down the right path but I + + align:start position:0% +leads you down the right path but I + + + align:start position:0% +leads you down the right path but I +think if you work by yourself uh all for + + align:start position:0% +think if you work by yourself uh all for + + + align:start position:0% +think if you work by yourself uh all for +a long period eventually you're just + + align:start position:0% +a long period eventually you're just + + + align:start position:0% +a long period eventually you're just +going to get stuck because it's hard to + + align:start position:0% +going to get stuck because it's hard to + + + align:start position:0% +going to get stuck because it's hard to +maintain that kind of momentum all by + + align:start position:0% +maintain that kind of momentum all by + + + align:start position:0% +maintain that kind of momentum all by +yourself but when you feed off the + + align:start position:0% +yourself but when you feed off the + + + align:start position:0% +yourself but when you feed off the +energy of other people you can really go + + align:start position:0% +energy of other people you can really go + + + align:start position:0% +energy of other people you can really go +much much farther it's also more fun + + align:start position:0% +much much farther it's also more fun + + + align:start position:0% +much much farther it's also more fun +because you get to be hanging out while + + align:start position:0% +because you get to be hanging out while + + + align:start position:0% +because you get to be hanging out while +you're doing it so \ No newline at end of file diff --git a/F5-87RM_zHA.txt b/F5-87RM_zHA.txt new file mode 100644 index 0000000000000000000000000000000000000000..cd76ae290a904e526ea949cbf60a6f2aca250d7e --- /dev/null +++ b/F5-87RM_zHA.txt @@ -0,0 +1,347 @@ +Today we're going to talk about how to translate +high-level languages into code that computers + +can execute. + +So far we've seen the Beta ISA, which includes +instructions that control the datapath operations + +performed on 32-bit data stored in the registers. + +There are also instructions for accessing +main memory and changing the program counter. + +The instructions are formatted as opcode, +source, and destination fields that form 32-bit + +values in main memory. + +To make our lives easier, we developed assembly +language as a way of specifying sequences + +of instructions. + +Each assembly language statement corresponds +to a single instruction. + +As assembly language programmers, we're responsible +for managing which values are in registers + +and which are in main memory, and we need +to figure out how to break down complicated + +operations, +e.g., accessing an element of an array, into + +the right sequence of Beta operations. + +We can go one step further and use high-level +languages to describe the computations we + +want to perform. + +These languages use variables and other data +structures to abstract away the details of + +storage allocation and the movement of data +to and from main memory. + +We can just refer to a data object by name +and let the language processor handle the + +details. + +Similarly, we'll write expressions and other +operators such as assignment (=) to efficiently + +describe what would require many statements +in assembly language. + +Today we're going to dive into how to translate +high-level language programs into code that + +will run on the Beta. + +Here we see Euclid's algorithm for determining +the greatest common divisor of two numbers, + +in this case the algorithm is written in the +C programming language. + +We'll be using a simple subset of C as our +example high-level language. + +Please see the brief overview of C in the +Handouts section if you'd like an introduction + +to C syntax and semantics. + +C was developed by Dennis Ritchie at AT&T +Bell Labs in the late 60's and early 70's + +to use when implementing the Unix operating +system. + +Since that time many new high-level languages +have been introduced providing modern abstractions + +like object-oriented programming along with +useful new data and control structures. + +Using C allows us describe a computation without +referring to any of the details of the Beta + +ISA like registers, specific Beta instructions, +and so on. + +The absence of such details means there is +less work required to create the program and + +makes it easier for others to read and understand +the algorithm implemented by the program. + +There are many advantages to using a high-level +language. + +They enable programmers to be very productive +since the programs are concise and readable. + +These attributes also make it easy to maintain +the code. + +Often it is harder to make certain types of +mistakes since the language allows us to check + +for silly errors like storing a string value +into a numeric variable. + +And more complicated tasks like dynamically +allocating and deallocating storage can be + +completely automated. + +The result is that it can take much less time +to create a correct program in a high-level + +language than it would it when writing in +assembly language. + +Since the high-level language has abstracted +away the details of a particular ISA, the + +programs are portable in the sense that we +can expect to run the same code on different + +ISAs without having to rewrite the code. + +What do we lose by using a high-level language? + +Should we worry that we'll pay a price in +terms of the efficiency and performance we + +might get by crafting each instruction by +hand? + +The answer depends on how we choose to run +high-level language programs. + +The two basic execution strategies are "interpretation" +and "compilation". + +To interpret a high-level language program, +we'll write a special program called an "interpreter" + +that runs on the actual computer, M1. + +The interpreter mimics the behavior of some +abstract easy-to-program machine M2 and for + +each M2 operation executes sequences of M1 +instructions to achieve the desired result. + +We can think of the interpreter along with +M1 as an implementation of M2, i.e., given + +a program written for M2, the interpreter +will, step-by-step, emulate the effect of + +M2 instructions. + +We often use several layers of interpretation +when tackling computation tasks. + +For example, an engineer may use her laptop +with an Intel CPU to run the Python interpreter. + +In Python, she loads the SciPy toolkit, which +provides a calculator-like interface for numerical + +analysis for matrices and data. + +For each SciPy command, e.g., "find the maximum +value of a dataset", the SciPy tool kit executes + +many Python statements, e.g., to loop over +each element of the array, remembering the + +largest value. + +For each Python statement, the Python interpreter +executes many x86 instructions, e.g., to increment + +the loop index and check for loop termination. + +Executing a single SciPy command may require +executing of tens of Python statements, which + +in turn each may require executing hundreds +of x86 instructions. + +The engineer is very happy she didn't have +to write each of those instructions herself! + +Interpretation is an effective implementation +strategy when performing a computation once, + +or when exploring which computational approach +is most effective before making a more substantial + +investment in creating a more efficient implementation. + +We'll use a compilation implementation strategy +when we have computational tasks that we need + +to execute repeatedly and hence we are willing +to invest more time up-front for more efficiency + +in the long-term. + +In compilation, we also start with our actual +computer M1. + +Then we'll take our high-level language program +P2 and translate it statement-by-statement + +into a program for M1. + +Note that we're not actually running the P2 +program. + +Instead we're using it as a template to create +an equivalent P1 program that can execute + +directly on M1. + +The translation process is called "compilation" +and the program that does the translation + +is called a "compiler". + +We compile the P2 program once to get the +translation P1, and then we'll run P1 on M1 + +whenever we want to execute P2. + +Running P1 avoids the overhead of having to +process the P2 source and the costs of executing + +any intervening layers of interpretation. + +Instead of dynamically figuring out the necessary +machine instructions for each P2 statement + +as it's encountered, +in effect we've arranged to capture that stream + +of machine instructions and save them as a +P1 program for later execution. + +If we're willing to pay the up-front costs +of compilation, we'll get more efficient execution. + +And, with different compilers, we can arrange +to run P2 on many different machines - M2, + +M3, etc. - without having rewrite P2. + +So we now have two ways to execute a high-level +language program: interpretation and compilation. + +Both allow us to change the original source +program. + +Both allow us to abstract away the details +of the actual computer we'll use to run the + +program. + +And both strategies are widely used in modern +computer systems! + +Let's summarize the differences between interpretation +and compilation. + +Suppose the statement "x+2" appears in the +high-level program. + +When the interpreter processes this statement +it immediately fetches the value of the variable + +x and adds 2 to it. + +On the other hand, the compiler would generate +Beta instructions that would LD the variable + +x into a register and then ADD 2 to that value. + +The interpreter is executing each statement +as it's processed and, in fact, may process + +and execute the same statement many times +if, e.g., it was in a loop. + +The compiler is just generating instructions +to be executed at some later time. + +Interpreters have the overhead of processing +the high-level source code during execution + +and that overhead may be incurred many times +in loops. + +Compilers incur the processing overhead once, +making the eventual execution more efficient. + +But during development, the programmer may +have to compile and run the program many times, + +often incurring the cost of compilation for +only a single execution of the program. + +So the compile-run-debug loop can take more +time. + +The interpreter is making decisions about +the data type of x and the type of operations + +necessary at run time, i.e., while the program +is running. + +The compiler is making those decisions during +the compilation process. + +Which is the better approach? + +In general, executing compiled code is much +faster than running the code interpretively. + +But since the interpreter is making decisions +at run time, it can change its behavior depending, + +say, on the type of the data in the variable +X, offering considerable flexibility in handling + +different types of data with the same algorithm. + +Compilers take away that flexibility in exchange +for fast execution. \ No newline at end of file diff --git a/FaLqAip6A0Q.txt b/FaLqAip6A0Q.txt new file mode 100644 index 0000000000000000000000000000000000000000..c8906b0df07f3c50e086960d99f4ec8af7349922 --- /dev/null +++ b/FaLqAip6A0Q.txt @@ -0,0 +1,14395 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +view additional materials from hundreds + + align:start position:0% +view additional materials from hundreds + + + align:start position:0% +view additional materials from hundreds +of MIT courses visit MIT opencourseware + + align:start position:0% +of MIT courses visit MIT opencourseware + + + align:start position:0% +of MIT courses visit MIT opencourseware +at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu + + align:start position:0% +ocw.mit.edu + + + align:start position:0% +ocw.mit.edu +so today what we're going to talk about + + align:start position:0% +so today what we're going to talk about + + + align:start position:0% +so today what we're going to talk about +we're going to move + + align:start position:0% +we're going to move + + + align:start position:0% +we're going to move +from sort of the descriptive discussions + + align:start position:0% +from sort of the descriptive discussions + + + align:start position:0% +from sort of the descriptive discussions +of organizational decisionmaking to a + + align:start position:0% +of organizational decisionmaking to a + + + align:start position:0% +of organizational decisionmaking to a +couple of prescriptive sessions which is + + align:start position:0% +couple of prescriptive sessions which is + + + align:start position:0% +couple of prescriptive sessions which is +if you're running an energy business how + + align:start position:0% +if you're running an energy business how + + + align:start position:0% +if you're running an energy business how +do you do it one of the things as this + + align:start position:0% +do you do it one of the things as this + + + align:start position:0% +do you do it one of the things as this +indicates that we talked about you + + align:start position:0% +indicates that we talked about you + + + align:start position:0% +indicates that we talked about you +should do you should be doing present + + align:start position:0% +should do you should be doing present + + + align:start position:0% +should do you should be doing present +value analysis Net Present Value + + align:start position:0% +value analysis Net Present Value + + + align:start position:0% +value analysis Net Present Value +analysis of investment + + align:start position:0% +analysis of investment + + + align:start position:0% +analysis of investment +opportunities but that's not strategy so + + align:start position:0% +opportunities but that's not strategy so + + + align:start position:0% +opportunities but that's not strategy so +today and next time we're going to be + + align:start position:0% +today and next time we're going to be + + + align:start position:0% +today and next time we're going to be +talking about strategy we'll talk about + + align:start position:0% +talking about strategy we'll talk about + + + align:start position:0% +talking about strategy we'll talk about +industry attractiveness + + align:start position:0% +industry attractiveness + + + align:start position:0% +industry attractiveness +briefly kinds of strategies and niches + + align:start position:0% +briefly kinds of strategies and niches + + + align:start position:0% +briefly kinds of strategies and niches +within Industries and then the Husky + + align:start position:0% +within Industries and then the Husky + + + align:start position:0% +within Industries and then the Husky +case Wednesday Don lassard's going to be + + align:start position:0% +case Wednesday Don lassard's going to be + + + align:start position:0% +case Wednesday Don lassard's going to be +here and explore with you uh business + + align:start position:0% +here and explore with you uh business + + + align:start position:0% +here and explore with you uh business +models particularly in Innovative + + align:start position:0% +models particularly in Innovative + + + align:start position:0% +models particularly in Innovative +segments so it isn't project by project + + align:start position:0% +segments so it isn't project by project + + + align:start position:0% +segments so it isn't project by project +Net Present Value isn't strategy if if a + + align:start position:0% +Net Present Value isn't strategy if if a + + + align:start position:0% +Net Present Value isn't strategy if if a +firm accepts every Proposal with a net + + align:start position:0% +firm accepts every Proposal with a net + + + align:start position:0% +firm accepts every Proposal with a net +present + + align:start position:0% +present + + + align:start position:0% +present +value a positive Net Present Value the + + align:start position:0% +value a positive Net Present Value the + + + align:start position:0% +value a positive Net Present Value the +result is likely to be very incoherent + + align:start position:0% +result is likely to be very incoherent + + + align:start position:0% +result is likely to be very incoherent +and + + align:start position:0% +and + + + align:start position:0% +and +unmanageable the Brey piece is a is sort + + align:start position:0% +unmanageable the Brey piece is a is sort + + + align:start position:0% +unmanageable the Brey piece is a is sort +of a finance person's + + align:start position:0% +of a finance person's + + + align:start position:0% +of a finance person's +skepticism the first thing you note is + + align:start position:0% +skepticism the first thing you note is + + + align:start position:0% +skepticism the first thing you note is +you only see proposals with positive Net + + align:start position:0% +you only see proposals with positive Net + + + align:start position:0% +you only see proposals with positive Net +Present + + align:start position:0% +Present + + + align:start position:0% +Present +Value uh if someone likes a project it + + align:start position:0% +Value uh if someone likes a project it + + + align:start position:0% +Value uh if someone likes a project it +turns out it has a positive Net Present + + align:start position:0% +turns out it has a positive Net Present + + + align:start position:0% +turns out it has a positive Net Present +Value + + align:start position:0% +Value + + + align:start position:0% +Value +so the what they propose and we'll + + align:start position:0% +so the what they propose and we'll + + + align:start position:0% +so the what they propose and we'll +explore a little bit is thinking about + + align:start position:0% +explore a little bit is thinking about + + + align:start position:0% +explore a little bit is thinking about +dise equilibrium thinking about will it + + align:start position:0% +dise equilibrium thinking about will it + + + align:start position:0% +dise equilibrium thinking about will it +last it has a Net Present Value because + + align:start position:0% +last it has a Net Present Value because + + + align:start position:0% +last it has a Net Present Value because +we're cheaper than they are okay why are + + align:start position:0% +we're cheaper than they are okay why are + + + align:start position:0% +we're cheaper than they are okay why are +we cheaper than they are we can buy + + align:start position:0% +we cheaper than they are we can buy + + + align:start position:0% +we cheaper than they are we can buy +materials more cheaply than they why + + align:start position:0% +materials more cheaply than they why + + + align:start position:0% +materials more cheaply than they why +will it last will it last anuka and I + + align:start position:0% +will it last will it last anuka and I + + + align:start position:0% +will it last will it last anuka and I +saw before vacation uh a very detailed + + align:start position:0% +saw before vacation uh a very detailed + + + align:start position:0% +saw before vacation uh a very detailed +analysis of US versus Chinese + + align:start position:0% +analysis of US versus Chinese + + + align:start position:0% +analysis of US versus Chinese +photovoltaic manufacturing costs that + + align:start position:0% +photovoltaic manufacturing costs that + + + align:start position:0% +photovoltaic manufacturing costs that +concluded that the big Chinese Advantage + + align:start position:0% +concluded that the big Chinese Advantage + + + align:start position:0% +concluded that the big Chinese Advantage +was they could materials and supplies + + align:start position:0% +was they could materials and supplies + + + align:start position:0% +was they could materials and supplies +25% cheaper and the first question is + + align:start position:0% +25% cheaper and the first question is + + + align:start position:0% +25% cheaper and the first question is +why is that going to last the people + + align:start position:0% +why is that going to last the people + + + align:start position:0% +why is that going to last the people +who' done the study hadn't quite + + align:start position:0% +who' done the study hadn't quite + + + align:start position:0% +who' done the study hadn't quite +inquired into that and said it was + + align:start position:0% +inquired into that and said it was + + + align:start position:0% +inquired into that and said it was +Superior bargaining + + align:start position:0% +Superior bargaining + + + align:start position:0% +Superior bargaining +power Superior bargaining power doesn't + + align:start position:0% +power Superior bargaining power doesn't + + + align:start position:0% +power Superior bargaining power doesn't +last so first first point in the bre at + + align:start position:0% +last so first first point in the bre at + + + align:start position:0% +last so first first point in the bre at +all piece is skepticism about present + + align:start position:0% +all piece is skepticism about present + + + align:start position:0% +all piece is skepticism about present +value Porter's paper is in a way more + + align:start position:0% +value Porter's paper is in a way more + + + align:start position:0% +value Porter's paper is in a way more +profound and really does deserve a + + align:start position:0% +profound and really does deserve a + + + align:start position:0% +profound and really does deserve a +serious read + + align:start position:0% + + + + align:start position:0% + +strategy Is What You Won't Do what is it + + align:start position:0% +strategy Is What You Won't Do what is it + + + align:start position:0% +strategy Is What You Won't Do what is it +you won't do as a company someone walks + + align:start position:0% +you won't do as a company someone walks + + + align:start position:0% +you won't do as a company someone walks +in the door with a project with a + + align:start position:0% +in the door with a project with a + + + align:start position:0% +in the door with a project with a +positive Net Present Value which when do + + align:start position:0% +positive Net Present Value which when do + + + align:start position:0% +positive Net Present Value which when do +you just say no you're right that's a + + align:start position:0% +you just say no you're right that's a + + + align:start position:0% +you just say no you're right that's a +positive Net Present Value we're not + + align:start position:0% +positive Net Present Value we're not + + + align:start position:0% +positive Net Present Value we're not +going to do + + align:start position:0% + + + + align:start position:0% + +it the argument is + + align:start position:0% +it the argument is + + + align:start position:0% +it the argument is +this if you're doing the same thing your + + align:start position:0% +this if you're doing the same thing your + + + align:start position:0% +this if you're doing the same thing your +competitors are you're in a wonderful + + align:start position:0% +competitors are you're in a wonderful + + + align:start position:0% +competitors are you're in a wonderful +world and there are a bunch of them + + align:start position:0% +world and there are a bunch of them + + + align:start position:0% +world and there are a bunch of them +you're in a wonderful world of perfect + + align:start position:0% +you're in a wonderful world of perfect + + + align:start position:0% +you're in a wonderful world of perfect +competition we all enjoy that it's in + + align:start position:0% +competition we all enjoy that it's in + + + align:start position:0% +competition we all enjoy that it's in +the textbooks it's easy to analyze and + + align:start position:0% +the textbooks it's easy to analyze and + + + align:start position:0% +the textbooks it's easy to analyze and +it's no + + align:start position:0% +it's no + + + align:start position:0% +it's no +fun you don't make any money + + align:start position:0% +fun you don't make any money + + + align:start position:0% +fun you don't make any money +particularly if there are opportunities + + align:start position:0% +particularly if there are opportunities + + + align:start position:0% +particularly if there are opportunities +to innovate you have to innovate just to + + align:start position:0% +to innovate you have to innovate just to + + + align:start position:0% +to innovate you have to innovate just to +cover your cost of + + align:start position:0% +cover your cost of + + + align:start position:0% +cover your cost of +capital there's a piece there's a little + + align:start position:0% +capital there's a piece there's a little + + + align:start position:0% +capital there's a piece there's a little +quote from Warren Buffett which I think + + align:start position:0% +quote from Warren Buffett which I think + + + align:start position:0% +quote from Warren Buffett which I think +still holds true that since the dawn of + + align:start position:0% +still holds true that since the dawn of + + + align:start position:0% +still holds true that since the dawn of +Aviation the total profits earned by + + align:start position:0% +Aviation the total profits earned by + + + align:start position:0% +Aviation the total profits earned by +Airlines adds up to + + align:start position:0% +Airlines adds up to + + + align:start position:0% +Airlines adds up to +zero Airlines have gotten enormously + + align:start position:0% +zero Airlines have gotten enormously + + + align:start position:0% +zero Airlines have gotten enormously +more efficient they've done enormous + + align:start position:0% +more efficient they've done enormous + + + align:start position:0% +more efficient they've done enormous +things for transportation for the + + align:start position:0% +things for transportation for the + + + align:start position:0% +things for transportation for the +country as a whole but they haven't made + + align:start position:0% +country as a whole but they haven't made + + + align:start position:0% +country as a whole but they haven't made +any money because mostly they're all + + align:start position:0% +any money because mostly they're all + + + align:start position:0% +any money because mostly they're all +doing the same thing and there are a + + align:start position:0% +doing the same thing and there are a + + + align:start position:0% +doing the same thing and there are a +bunch of them and there's no + + align:start position:0% +bunch of them and there's no + + + align:start position:0% +bunch of them and there's no +differentiation or stickiness + + align:start position:0% +differentiation or stickiness + + + align:start position:0% +differentiation or stickiness +so the first lesson is if you're running + + align:start position:0% +so the first lesson is if you're running + + + align:start position:0% +so the first lesson is if you're running +a company you don't want to be + + align:start position:0% + + + + align:start position:0% + +there as Porter points out if you're in + + align:start position:0% +there as Porter points out if you're in + + + align:start position:0% +there as Porter points out if you're in +that situation I mean Airlines have + + align:start position:0% +that situation I mean Airlines have + + + align:start position:0% +that situation I mean Airlines have +improved efficiency enormously over the + + align:start position:0% +improved efficiency enormously over the + + + align:start position:0% +improved efficiency enormously over the +years fuel costs are down electronic + + align:start position:0% +years fuel costs are down electronic + + + align:start position:0% +years fuel costs are down electronic +reservation systems baggage handling + + align:start position:0% +reservation systems baggage handling + + + align:start position:0% +reservation systems baggage handling +much more efficient than they used to be + + align:start position:0% +much more efficient than they used to be + + + align:start position:0% +much more efficient than they used to be +and they're still not making any money + + align:start position:0% +and they're still not making any money + + + align:start position:0% +and they're still not making any money +because they're all doing it and if you + + align:start position:0% +because they're all doing it and if you + + + align:start position:0% +because they're all doing it and if you +don't innovate and improve you lose + + align:start position:0% +don't innovate and improve you lose + + + align:start position:0% +don't innovate and improve you lose +Andrew just drying your nail polish okay + + align:start position:0% +Andrew just drying your nail polish okay + + + align:start position:0% +Andrew just drying your nail polish okay +good + + align:start position:0% +good + + + align:start position:0% +good +good it's important to important to have + + align:start position:0% +good it's important to important to have + + + align:start position:0% +good it's important to important to have +it dry um so lesson one is you don't + + align:start position:0% +it dry um so lesson one is you don't + + + align:start position:0% +it dry um so lesson one is you don't +want to do that + + align:start position:0% +want to do that + + + align:start position:0% +want to do that +lesson two is sort of the obvious + + align:start position:0% +lesson two is sort of the obvious + + + align:start position:0% +lesson two is sort of the obvious +Counterpoint which is well when you set + + align:start position:0% +Counterpoint which is well when you set + + + align:start position:0% +Counterpoint which is well when you set +up a business you'd like to be doing + + align:start position:0% +up a business you'd like to be doing + + + align:start position:0% +up a business you'd like to be doing +something get a value to somebody that + + align:start position:0% +something get a value to somebody that + + + align:start position:0% +something get a value to somebody that +can't be easily imitated the buzzword is + + align:start position:0% +can't be easily imitated the buzzword is + + + align:start position:0% +can't be easily imitated the buzzword is +sustainable + + align:start position:0% +sustainable + + + align:start position:0% +sustainable +Advantage so the notion that Chinese + + align:start position:0% +Advantage so the notion that Chinese + + + align:start position:0% +Advantage so the notion that Chinese +photovoltaics will always be cheaper + + align:start position:0% +photovoltaics will always be cheaper + + + align:start position:0% +photovoltaics will always be cheaper +because Chinese bargaining power enables + + align:start position:0% +because Chinese bargaining power enables + + + align:start position:0% +because Chinese bargaining power enables +them to get silicon 25% cheaper than us + + align:start position:0% +them to get silicon 25% cheaper than us + + + align:start position:0% +them to get silicon 25% cheaper than us +firms that doesn't wash if that's what's + + align:start position:0% +firms that doesn't wash if that's what's + + + align:start position:0% +firms that doesn't wash if that's what's +going on that's not + + align:start position:0% +going on that's not + + + align:start position:0% +going on that's not +sustainable if there's some cost + + align:start position:0% +sustainable if there's some cost + + + align:start position:0% +sustainable if there's some cost +advantage in Silicon production that's + + align:start position:0% +advantage in Silicon production that's + + + align:start position:0% +advantage in Silicon production that's +more interesting but if all you know is + + align:start position:0% +more interesting but if all you know is + + + align:start position:0% +more interesting but if all you know is +it's cheaper and all you hear is + + align:start position:0% +it's cheaper and all you hear is + + + align:start position:0% +it's cheaper and all you hear is +bargaining power that's not + + align:start position:0% +bargaining power that's not + + + align:start position:0% +bargaining power that's not +sustainable so if strategy is what you + + align:start position:0% +sustainable so if strategy is what you + + + align:start position:0% +sustainable so if strategy is what you +don't do and it needs to be something + + align:start position:0% +don't do and it needs to be something + + + align:start position:0% +don't do and it needs to be something +that can't easily be imitated how about + + align:start position:0% +that can't easily be imitated how about + + + align:start position:0% +that can't easily be imitated how about +the question I posed there does MIT have + + align:start position:0% +the question I posed there does MIT have + + + align:start position:0% +the question I posed there does MIT have +a + + align:start position:0% + + + + align:start position:0% + +strategy if so what is it or what are + + align:start position:0% +strategy if so what is it or what are + + + align:start position:0% +strategy if so what is it or what are +what are elements of + + align:start position:0% +what are elements of + + + align:start position:0% +what are elements of +it yeah Hands On Learning Hands-On + + align:start position:0% +it yeah Hands On Learning Hands-On + + + align:start position:0% +it yeah Hands On Learning Hands-On +learning okay what is that rule + + align:start position:0% +learning okay what is that rule + + + align:start position:0% +learning okay what is that rule +out I it's an element of what MIT is + + align:start position:0% +out I it's an element of what MIT is + + + align:start position:0% +out I it's an element of what MIT is +about + + align:start position:0% + + + + align:start position:0% + +absolutely Lim + + align:start position:0% +absolutely Lim + + + align:start position:0% +absolutely Lim +people have ,000 + + align:start position:0% +people have ,000 + + + align:start position:0% +people have ,000 +people okay so it's a it's a high cost + + align:start position:0% +people okay so it's a it's a high cost + + + align:start position:0% +people okay so it's a it's a high cost +strategy um what's it say about + + align:start position:0% +strategy um what's it say about + + + align:start position:0% +strategy um what's it say about +the kinds of things you teach medical + + align:start position:0% +the kinds of things you teach medical + + + align:start position:0% +the kinds of things you teach medical +school has has Hands-On learning MIT + + align:start position:0% +school has has Hands-On learning MIT + + + align:start position:0% +school has has Hands-On learning MIT +doesn't have a medical + + align:start position:0% + + + + align:start position:0% + +school simpler question Caroline what's + + align:start position:0% +school simpler question Caroline what's + + + align:start position:0% +school simpler question Caroline what's +Welsley strategy does Welsley have a + + align:start position:0% +Welsley strategy does Welsley have a + + + align:start position:0% +Welsley strategy does Welsley have a +strategy um yes to educate women educate + + align:start position:0% +strategy um yes to educate women educate + + + align:start position:0% +strategy um yes to educate women educate +women in everything as well as they have + + align:start position:0% +women in everything as well as they have + + + align:start position:0% +women in everything as well as they have +a big engineering + + align:start position:0% +a big engineering + + + align:start position:0% +a big engineering +school liberal arts focuses on women + + align:start position:0% +school liberal arts focuses on women + + + align:start position:0% +school liberal arts focuses on women +focuses on liberal arts doesn't offer + + align:start position:0% +focuses on liberal arts doesn't offer + + + align:start position:0% +focuses on liberal arts doesn't offer +graduate + + align:start position:0% +graduate + + + align:start position:0% +graduate +degrees stays small that's pretty easy + + align:start position:0% +degrees stays small that's pretty easy + + + align:start position:0% +degrees stays small that's pretty easy +what about MIT it's more than just + + align:start position:0% +what about MIT it's more than just + + + align:start position:0% +what about MIT it's more than just +Hands-On learning MIT doesn't have a law + + align:start position:0% +Hands-On learning MIT doesn't have a law + + + align:start position:0% +Hands-On learning MIT doesn't have a law +school Harvard has a law school + + align:start position:0% +school Harvard has a law school + + + align:start position:0% +school Harvard has a law school +Harvard's had a law school for a long + + align:start position:0% +Harvard's had a law school for a long + + + align:start position:0% +Harvard's had a law school for a long +time presumably those are strategic + + align:start position:0% + + + + align:start position:0% + +differences yes somebody actually sat + + align:start position:0% +differences yes somebody actually sat + + + align:start position:0% +differences yes somebody actually sat +down and said why should MIT have a law + + align:start position:0% +down and said why should MIT have a law + + + align:start position:0% +down and said why should MIT have a law +school no MIT shouldn't I mean that + + align:start position:0% +school no MIT shouldn't I mean that + + + align:start position:0% +school no MIT shouldn't I mean that +decision's been looked at several times + + align:start position:0% +decision's been looked at several times + + + align:start position:0% +decision's been looked at several times +in history why do you + + align:start position:0% + + + + align:start position:0% + +think so they can focus on being the + + align:start position:0% +think so they can focus on being the + + + align:start position:0% +think so they can focus on being the +best in science and engineering it + + align:start position:0% +best in science and engineering it + + + align:start position:0% +best in science and engineering it +focuses on science and engineering and + + align:start position:0% +focuses on science and engineering and + + + align:start position:0% +focuses on science and engineering and +things that compl and work with + + align:start position:0% +things that compl and work with + + + align:start position:0% +things that compl and work with +it so does economics make sense yeah it + + align:start position:0% +it so does economics make sense yeah it + + + align:start position:0% +it so does economics make sense yeah it +does historically it does one of the + + align:start position:0% +does historically it does one of the + + + align:start position:0% +does historically it does one of the +early presidents of MIT was the founder + + align:start position:0% +early presidents of MIT was the founder + + + align:start position:0% +early presidents of MIT was the founder +of the American economic Association so + + align:start position:0% +of the American economic Association so + + + align:start position:0% +of the American economic Association so +somebody thought it made sense um we've + + align:start position:0% +somebody thought it made sense um we've + + + align:start position:0% +somebody thought it made sense um we've +done business for a long time since + + align:start position:0% +done business for a long time since + + + align:start position:0% +done business for a long time since +almost since the start of the + + align:start position:0% +almost since the start of the + + + align:start position:0% +almost since the start of the +Institute how about + + align:start position:0% +Institute how about + + + align:start position:0% +Institute how about +Linguistics why do we do + + align:start position:0% + + + + align:start position:0% + +Linguistics H well I've heard it's lar + + align:start position:0% +Linguistics H well I've heard it's lar + + + align:start position:0% +Linguistics H well I've heard it's lar +because can't + + align:start position:0% +because can't + + + align:start position:0% +because can't +develop yeah I think that's the right + + align:start position:0% +develop yeah I think that's the right + + + align:start position:0% +develop yeah I think that's the right +answer I mean my sense is a whole bunch + + align:start position:0% +answer I mean my sense is a whole bunch + + + align:start position:0% +answer I mean my sense is a whole bunch +of decisions have been made that a whole + + align:start position:0% +of decisions have been made that a whole + + + align:start position:0% +of decisions have been made that a whole +bunch of areas will be basically service + + align:start position:0% +bunch of areas will be basically service + + + align:start position:0% +bunch of areas will be basically service +departments so that we can actually give + + align:start position:0% +departments so that we can actually give + + + align:start position:0% +departments so that we can actually give +a rounded + + align:start position:0% +a rounded + + + align:start position:0% +a rounded +education and into that history we don't + + align:start position:0% +education and into that history we don't + + + align:start position:0% +education and into that history we don't +do Advanced degrees in history uh and + + align:start position:0% +do Advanced degrees in history uh and + + + align:start position:0% +do Advanced degrees in history uh and +sociology we don't have psychology is + + align:start position:0% +sociology we don't have psychology is + + + align:start position:0% +sociology we don't have psychology is +very focused but but into languages and + + align:start position:0% +very focused but but into languages and + + + align:start position:0% +very focused but but into languages and +Linguistics stumbles gome Chomsky and + + align:start position:0% +Linguistics stumbles gome Chomsky and + + + align:start position:0% +Linguistics stumbles gome Chomsky and +you say oh my God what an opportunity + + align:start position:0% +you say oh my God what an opportunity + + + align:start position:0% +you say oh my God what an opportunity +this is and so you build on him but it's + + align:start position:0% +this is and so you build on him but it's + + + align:start position:0% +this is and so you build on him but it's +not a big department and it's pretty + + align:start position:0% +not a big department and it's pretty + + + align:start position:0% +not a big department and it's pretty +focused and we don't have a lot of + + align:start position:0% +focused and we don't have a lot of + + + align:start position:0% +focused and we don't have a lot of +modern languages we don't have a French + + align:start position:0% +modern languages we don't have a French + + + align:start position:0% +modern languages we don't have a French +Department we don't have a Spanish + + align:start position:0% +Department we don't have a Spanish + + + align:start position:0% +Department we don't have a Spanish +Department there's probably a French + + align:start position:0% +Department there's probably a French + + + align:start position:0% +Department there's probably a French +department at Welsley yes yeah we don't + + align:start position:0% +department at Welsley yes yeah we don't + + + align:start position:0% +department at Welsley yes yeah we don't +have one so MIT does have a strategy + + align:start position:0% +have one so MIT does have a strategy + + + align:start position:0% +have one so MIT does have a strategy +it's not + + align:start position:0% +it's not + + + align:start position:0% +it's not +perfectly not easily written down but I + + align:start position:0% +perfectly not easily written down but I + + + align:start position:0% +perfectly not easily written down but I +mean the the Strategic descriptions have + + align:start position:0% +mean the the Strategic descriptions have + + + align:start position:0% +mean the the Strategic descriptions have +to do with science engineering and + + align:start position:0% +to do with science engineering and + + + align:start position:0% +to do with science engineering and +related fields and complimentary Fields + + align:start position:0% +related fields and complimentary Fields + + + align:start position:0% +related fields and complimentary Fields +Welsley is pretty clear Harvard's + + align:start position:0% +Welsley is pretty clear Harvard's + + + align:start position:0% +Welsley is pretty clear Harvard's +is we do almost everything we're a full + + align:start position:0% +is we do almost everything we're a full + + + align:start position:0% +is we do almost everything we're a full +service + + align:start position:0% +service + + + align:start position:0% +service +supplier it is interesting Harvard + + align:start position:0% +supplier it is interesting Harvard + + + align:start position:0% +supplier it is interesting Harvard +doesn't have a veterinary school I'm + + align:start position:0% +doesn't have a veterinary school I'm + + + align:start position:0% +doesn't have a veterinary school I'm +quite sure why but but they have just + + align:start position:0% +quite sure why but but they have just + + + align:start position:0% +quite sure why but but they have just +about everything else you could think + + align:start position:0% +about everything else you could think + + + align:start position:0% +about everything else you could think +about just I don't I don't think they + + align:start position:0% +about just I don't I don't think they + + + align:start position:0% +about just I don't I don't think they +have Library science but just about + + align:start position:0% +have Library science but just about + + + align:start position:0% +have Library science but just about +everything else so those are very those + + align:start position:0% +everything else so those are very those + + + align:start position:0% +everything else so those are very those +are strategies MIT has faced the + + align:start position:0% +are strategies MIT has faced the + + + align:start position:0% +are strategies MIT has faced the +possibility of a law school MIT could + + align:start position:0% +possibility of a law school MIT could + + + align:start position:0% +possibility of a law school MIT could +make money with a law school has decided + + align:start position:0% +make money with a law school has decided + + + align:start position:0% +make money with a law school has decided +not to do it has decided not to have a + + align:start position:0% +not to do it has decided not to have a + + + align:start position:0% +not to do it has decided not to have a +medical + + align:start position:0% +medical + + + align:start position:0% +medical +school that's a harder call that's a + + align:start position:0% +school that's a harder call that's a + + + align:start position:0% +school that's a harder call that's a +more interesting call but has decided + + align:start position:0% +more interesting call but has decided + + + align:start position:0% +more interesting call but has decided +not to do a medical school + + align:start position:0% +not to do a medical school + + + align:start position:0% +not to do a medical school +strategy is to an important extent What + + align:start position:0% +strategy is to an important extent What + + + align:start position:0% +strategy is to an important extent What +You Won't Do and you could certainly do + + align:start position:0% +You Won't Do and you could certainly do + + + align:start position:0% +You Won't Do and you could certainly do +a net presentes value calculation for + + align:start position:0% +a net presentes value calculation for + + + align:start position:0% +a net presentes value calculation for +the MIT medical + + align:start position:0% +the MIT medical + + + align:start position:0% +the MIT medical +school and come out with a positive and + + align:start position:0% +school and come out with a positive and + + + align:start position:0% +school and come out with a positive and +also social impact you could also talk + + align:start position:0% +also social impact you could also talk + + + align:start position:0% +also social impact you could also talk +about a law school with heavy focus on + + align:start position:0% +about a law school with heavy focus on + + + align:start position:0% +about a law school with heavy focus on +patent law and intellectual and related + + align:start position:0% +patent law and intellectual and related + + + align:start position:0% +patent law and intellectual and related +intellectual property fields which does + + align:start position:0% +intellectual property fields which does + + + align:start position:0% +intellectual property fields which does +to a certain extent + + align:start position:0% +to a certain extent + + + align:start position:0% +to a certain extent +compliment but also distracts and that's + + align:start position:0% +compliment but also distracts and that's + + + align:start position:0% +compliment but also distracts and that's +a strategic choice so univ I ities like + + align:start position:0% +a strategic choice so univ I ities like + + + align:start position:0% +a strategic choice so univ I ities like +all kinds of other organizations need to + + align:start position:0% +all kinds of other organizations need to + + + align:start position:0% +all kinds of other organizations need to +have strategic need to make strategic + + align:start position:0% +have strategic need to make strategic + + + align:start position:0% +have strategic need to make strategic +choices another another strategy might + + align:start position:0% +choices another another strategy might + + + align:start position:0% +choices another another strategy might +be we'll do we'll do almost anything + + align:start position:0% +be we'll do we'll do almost anything + + + align:start position:0% +be we'll do we'll do almost anything +that will turn a profit and you see some + + align:start position:0% +that will turn a profit and you see some + + + align:start position:0% +that will turn a profit and you see some +places look like that MIT very much + + align:start position:0% +places look like that MIT very much + + + align:start position:0% +places look like that MIT very much +doesn't so if you're really thinking + + align:start position:0% +doesn't so if you're really thinking + + + align:start position:0% +doesn't so if you're really thinking +about a sustainable advantage of some + + align:start position:0% +about a sustainable advantage of some + + + align:start position:0% +about a sustainable advantage of some +sort a coherent strategy you have to + + align:start position:0% + + + + align:start position:0% + +consider you have to consider the next + + align:start position:0% +consider you have to consider the next + + + align:start position:0% +consider you have to consider the next +bullet or + + align:start position:0% +bullet or + + + align:start position:0% +bullet or +not okay what the next bullet says is + + align:start position:0% +not okay what the next bullet says is + + + align:start position:0% +not okay what the next bullet says is +when the slide works you have to think + + align:start position:0% +when the slide works you have to think + + + align:start position:0% +when the slide works you have to think +about + + align:start position:0% +about + + + align:start position:0% +about +complementarities or fit among + + align:start position:0% +complementarities or fit among + + + align:start position:0% +complementarities or fit among +investment + + align:start position:0% +investment + + + align:start position:0% +investment +projects meantime I'm going to figure + + align:start position:0% +projects meantime I'm going to figure + + + align:start position:0% +projects meantime I'm going to figure +out why this works the why this doesn't + + align:start position:0% +out why this works the why this doesn't + + + align:start position:0% +out why this works the why this doesn't +work the nice piece that we + + align:start position:0% +work the nice piece that we + + + align:start position:0% +work the nice piece that we +had okay tech support please I have a + + align:start position:0% +had okay tech support please I have a + + + align:start position:0% +had okay tech support please I have a +frozen machine at the moment there are + + align:start position:0% +frozen machine at the moment there are + + + align:start position:0% +frozen machine at the moment there are +nice examples in Porter about Ikea and + + align:start position:0% +nice examples in Porter about Ikea and + + + align:start position:0% +nice examples in Porter about Ikea and +about Southwest + + align:start position:0% +about Southwest + + + align:start position:0% +about Southwest +Airlines and they're great examples of + + align:start position:0% +Airlines and they're great examples of + + + align:start position:0% +Airlines and they're great examples of +taking on things that fit together right + + align:start position:0% +taking on things that fit together right + + + align:start position:0% +taking on things that fit together right +Southwest Airlines doesn't offer food + + align:start position:0% +Southwest Airlines doesn't offer food + + + align:start position:0% +Southwest Airlines doesn't offer food +Southwest Airlines flies out of small + + align:start position:0% +Southwest Airlines flies out of small + + + align:start position:0% +Southwest Airlines flies out of small +airports Southwest Airlines flies one + + align:start position:0% +airports Southwest Airlines flies one + + + align:start position:0% +airports Southwest Airlines flies one +kind of + + align:start position:0% +kind of + + + align:start position:0% +kind of +airplane all those things fit together + + align:start position:0% +airplane all those things fit together + + + align:start position:0% +airplane all those things fit together +lowcost + + align:start position:0% +lowcost + + + align:start position:0% +lowcost +convenient lowcost convenient you could + + align:start position:0% +convenient lowcost convenient you could + + + align:start position:0% +convenient lowcost convenient you could +make a case that g if we had more if we + + align:start position:0% +make a case that g if we had more if we + + + align:start position:0% +make a case that g if we had more if we +had uh oh and you don't book through + + align:start position:0% +had uh oh and you don't book through + + + align:start position:0% +had uh oh and you don't book through +online + + align:start position:0% +online + + + align:start position:0% +online +services You Had A Hammer no I have ah + + align:start position:0% +services You Had A Hammer no I have ah + + + align:start position:0% +services You Had A Hammer no I have ah +okay thank + + align:start position:0% +okay thank + + + align:start position:0% +okay thank +you all right we're going to try to do + + align:start position:0% +you all right we're going to try to do + + + align:start position:0% +you all right we're going to try to do +this without slides it's going to be + + align:start position:0% +this without slides it's going to be + + + align:start position:0% +this without slides it's going to be +good uh the + + align:start position:0% + + + + align:start position:0% + +um the examples there are things that + + align:start position:0% +um the examples there are things that + + + align:start position:0% +um the examples there are things that +fit together you could imagine Southwest + + align:start position:0% +fit together you could imagine Southwest + + + align:start position:0% +fit together you could imagine Southwest +doing a calculation and saying well if + + align:start position:0% +doing a calculation and saying well if + + + align:start position:0% +doing a calculation and saying well if +we used online booking Services we'd get + + align:start position:0% +we used online booking Services we'd get + + + align:start position:0% +we used online booking Services we'd get +more volume and that'll cost us x% and + + align:start position:0% +more volume and that'll cost us x% and + + + align:start position:0% +more volume and that'll cost us x% and +you could imagine saying well it'll + + align:start position:0% +you could imagine saying well it'll + + + align:start position:0% +you could imagine saying well it'll +increase our costs a little bit but + + align:start position:0% +increase our costs a little bit but + + + align:start position:0% +increase our costs a little bit but +it'll pay off they have a Relentless + + align:start position:0% +it'll pay off they have a Relentless + + + align:start position:0% +it'll pay off they have a Relentless +focus on costs we're not going to do it + + align:start position:0% +focus on costs we're not going to do it + + + align:start position:0% +focus on costs we're not going to do it +we're not going to have assigned seats + + align:start position:0% +we're not going to have assigned seats + + + align:start position:0% +we're not going to have assigned seats +that takes time and extra gate Personnel + + align:start position:0% +that takes time and extra gate Personnel + + + align:start position:0% +that takes time and extra gate Personnel +we're not going to f we're not going to + + align:start position:0% +we're not going to f we're not going to + + + align:start position:0% +we're not going to f we're not going to +do online reservations because that + + align:start position:0% +do online reservations because that + + + align:start position:0% +do online reservations because that +limits that that'll increase our costs + + align:start position:0% +limits that that'll increase our costs + + + align:start position:0% +limits that that'll increase our costs +we're going to be lowcost convenient + + align:start position:0% +we're going to be lowcost convenient + + + align:start position:0% +we're going to be lowcost convenient +we're not going to have different kinds + + align:start position:0% +we're not going to have different kinds + + + align:start position:0% +we're not going to have different kinds +of planes even though on some routes we + + align:start position:0% +of planes even though on some routes we + + + align:start position:0% +of planes even though on some routes we +might want to fly larger planes because + + align:start position:0% +might want to fly larger planes because + + + align:start position:0% +might want to fly larger planes because +that'll increase our costs so Southwest + + align:start position:0% +that'll increase our costs so Southwest + + + align:start position:0% +that'll increase our costs so Southwest +thinks about how its decisions fit + + align:start position:0% +thinks about how its decisions fit + + + align:start position:0% +thinks about how its decisions fit +together similarly the example of + + align:start position:0% +together similarly the example of + + + align:start position:0% +together similarly the example of +Ikea which you all probably know better + + align:start position:0% +Ikea which you all probably know better + + + align:start position:0% +Ikea which you all probably know better +than I do but but you go into a + + align:start position:0% +than I do but but you go into a + + + align:start position:0% +than I do but but you go into a +traditional furniture store you can get + + align:start position:0% +traditional furniture store you can get + + + align:start position:0% +traditional furniture store you can get +all kinds of different things you order + + align:start position:0% +all kinds of different things you order + + + align:start position:0% +all kinds of different things you order +them many Fabrics many styles it takes + + align:start position:0% +them many Fabrics many styles it takes + + + align:start position:0% +them many Fabrics many styles it takes +six to 8 weeks some some slave in North + + align:start position:0% +six to 8 weeks some some slave in North + + + align:start position:0% +six to 8 weeks some some slave in North +Carolina makes it and it's shipped + + align:start position:0% +Carolina makes it and it's shipped + + + align:start position:0% +Carolina makes it and it's shipped +up I K doesn't offer that doesn't offer + + align:start position:0% +up I K doesn't offer that doesn't offer + + + align:start position:0% +up I K doesn't offer that doesn't offer +the customization it offers cost + + align:start position:0% +the customization it offers cost + + + align:start position:0% +the customization it offers cost +convenience and a certain + + align:start position:0% +convenience and a certain + + + align:start position:0% +convenience and a certain +look that's what it focuses on all of + + align:start position:0% +look that's what it focuses on all of + + + align:start position:0% +look that's what it focuses on all of +its decisions aim for that so that's a + + align:start position:0% +its decisions aim for that so that's a + + + align:start position:0% +its decisions aim for that so that's a +coherent strategy you you don't just + + align:start position:0% +coherent strategy you you don't just + + + align:start position:0% +coherent strategy you you don't just +take anything with a positive Net + + align:start position:0% +take anything with a positive Net + + + align:start position:0% +take anything with a positive Net +Present Value you ask how does it fit + + align:start position:0% +Present Value you ask how does it fit + + + align:start position:0% +Present Value you ask how does it fit +with what we're trying to do how does it + + align:start position:0% +with what we're trying to do how does it + + + align:start position:0% +with what we're trying to do how does it +fit with what we're trying to do an MIT + + align:start position:0% +fit with what we're trying to do an MIT + + + align:start position:0% +fit with what we're trying to do an MIT +law + + align:start position:0% +law + + + align:start position:0% +law +school might have positive might have + + align:start position:0% +school might have positive might have + + + align:start position:0% +school might have positive might have +positive benefits how does it fit with + + align:start position:0% +positive benefits how does it fit with + + + align:start position:0% +positive benefits how does it fit with +the main focus how would the Law School + + align:start position:0% +the main focus how would the Law School + + + align:start position:0% +the main focus how would the Law School +faculty interact with other faculty + + align:start position:0% +faculty interact with other faculty + + + align:start position:0% +faculty interact with other faculty +would it be the kinds of people who will + + align:start position:0% +would it be the kinds of people who will + + + align:start position:0% +would it be the kinds of people who will +fit well on the campus how would law + + align:start position:0% +fit well on the campus how would law + + + align:start position:0% +fit well on the campus how would law +students relate da da da da da that's + + align:start position:0% +students relate da da da da da that's + + + align:start position:0% +students relate da da da da da that's +that's not to say that that's an obvious + + align:start position:0% +that's not to say that that's an obvious + + + align:start position:0% +that's not to say that that's an obvious +question I always think a a more + + align:start position:0% +question I always think a a more + + + align:start position:0% +question I always think a a more +interesting strategic choice is should + + align:start position:0% +interesting strategic choice is should + + + align:start position:0% +interesting strategic choice is should +MIT invest more in public policy we have + + align:start position:0% +MIT invest more in public policy we have + + + align:start position:0% +MIT invest more in public policy we have +uh STS and so forth we don't have the + + align:start position:0% +uh STS and so forth we don't have the + + + align:start position:0% +uh STS and so forth we don't have the +Kennedy School you could imagine a case + + align:start position:0% +Kennedy School you could imagine a case + + + align:start position:0% +Kennedy School you could imagine a case +being made for a serious public public + + align:start position:0% +being made for a serious public public + + + align:start position:0% +being made for a serious public public +policy School focused on science and + + align:start position:0% +policy School focused on science and + + + align:start position:0% +policy School focused on science and +technology that case hasn't been made + + align:start position:0% +technology that case hasn't been made + + + align:start position:0% +technology that case hasn't been made +and that's a money Loser by the way but + + align:start position:0% +and that's a money Loser by the way but + + + align:start position:0% +and that's a money Loser by the way but +it might be it might have other + + align:start position:0% +it might be it might have other + + + align:start position:0% +it might be it might have other +strategic value any hope they have to + + align:start position:0% +strategic value any hope they have to + + + align:start position:0% +strategic value any hope they have to +REO the machine they have to reboot the + + align:start position:0% +REO the machine they have to reboot the + + + align:start position:0% +REO the machine they have to reboot the +machine + + align:start position:0% +machine + + + align:start position:0% +machine +okay we now go to Blackboard for the + + align:start position:0% +okay we now go to Blackboard for the + + + align:start position:0% +okay we now go to Blackboard for the +next + + align:start position:0% +next + + + align:start position:0% +next +Slide the next slide has to do + + align:start position:0% +Slide the next slide has to do + + + align:start position:0% +Slide the next slide has to do +with and I can't do Blackboard with a + + align:start position:0% +with and I can't do Blackboard with a + + + align:start position:0% +with and I can't do Blackboard with a +jacket on so so the next slide has to do + + align:start position:0% +jacket on so so the next slide has to do + + + align:start position:0% +jacket on so so the next slide has to do +with industry + + align:start position:0% + + + + align:start position:0% + +attractiveness so as I said this is + + align:start position:0% +attractiveness so as I said this is + + + align:start position:0% +attractiveness so as I said this is +about thinking + + align:start position:0% +about thinking + + + align:start position:0% +about thinking +about what activities you are doing what + + align:start position:0% +about what activities you are doing what + + + align:start position:0% +about what activities you are doing what +are you offering customers if you're + + align:start position:0% +are you offering customers if you're + + + align:start position:0% +are you offering customers if you're +offering customers the same things as a + + align:start position:0% +offering customers the same things as a + + + align:start position:0% +offering customers the same things as a +lot of competitors then you can be + + align:start position:0% +lot of competitors then you can be + + + align:start position:0% +lot of competitors then you can be +really good but unless there's some way + + align:start position:0% +really good but unless there's some way + + + align:start position:0% +really good but unless there's some way +you're better that can't be imitated + + align:start position:0% +you're better that can't be imitated + + + align:start position:0% +you're better that can't be imitated +you've got a problem so so if you look + + align:start position:0% +you've got a problem so so if you look + + + align:start position:0% +you've got a problem so so if you look +at an + + align:start position:0% +at an + + + align:start position:0% +at an +industry and you + + align:start position:0% +industry and you + + + align:start position:0% +industry and you +ask what things affect + + align:start position:0% +ask what things affect + + + align:start position:0% +ask what things affect +profits one thing is the intensity of + + align:start position:0% + + + + align:start position:0% + +competition another thing is pressure + + align:start position:0% +competition another thing is pressure + + + align:start position:0% +competition another thing is pressure +from suppliers I'll give you examples in + + align:start position:0% +from suppliers I'll give you examples in + + + align:start position:0% +from suppliers I'll give you examples in +a + + align:start position:0% + + + + align:start position:0% + +minute another thing is pressure from + + align:start position:0% +minute another thing is pressure from + + + align:start position:0% +minute another thing is pressure from +buyers + + align:start position:0% + + + + align:start position:0% + +substitutes and + + align:start position:0% + + + + align:start position:0% + +entry this is the famous uh this is an + + align:start position:0% +entry this is the famous uh this is an + + + align:start position:0% +entry this is the famous uh this is an +ugly version of the famous Mike + + align:start position:0% + + + + align:start position:0% + +Porter five forces + + align:start position:0% + + + + align:start position:0% + +if you understand this fully you're a + + align:start position:0% +if you understand this fully you're a + + + align:start position:0% +if you understand this fully you're a +third of the way through the MBA course + + align:start position:0% +third of the way through the MBA course + + + align:start position:0% +third of the way through the MBA course +in strategy so let me let me try to do + + align:start position:0% +in strategy so let me let me try to do + + + align:start position:0% +in strategy so let me let me try to do +it quickly it's not very + + align:start position:0% +it quickly it's not very + + + align:start position:0% +it quickly it's not very +hard + + align:start position:0% +hard + + + align:start position:0% +hard +uh maybe maybe only a quarter of the way + + align:start position:0% +uh maybe maybe only a quarter of the way + + + align:start position:0% +uh maybe maybe only a quarter of the way +through look I mean regardless + + align:start position:0% +through look I mean regardless + + + align:start position:0% +through look I mean regardless +regardless of what the what the supply + + align:start position:0% +regardless of what the what the supply + + + align:start position:0% +regardless of what the what the supply +conditions are and whether they're + + align:start position:0% +conditions are and whether they're + + + align:start position:0% +conditions are and whether they're +entrance or not if if the industry is + + align:start position:0% +entrance or not if if the industry is + + + align:start position:0% +entrance or not if if the industry is +perfectly competitive nobody makes any + + align:start position:0% +perfectly competitive nobody makes any + + + align:start position:0% +perfectly competitive nobody makes any +money that's sort of the definition and + + align:start position:0% +money that's sort of the definition and + + + align:start position:0% +money that's sort of the definition and +obviously competition runs along some + + align:start position:0% +obviously competition runs along some + + + align:start position:0% +obviously competition runs along some +sort of spectrum between a lot of small + + align:start position:0% +sort of spectrum between a lot of small + + + align:start position:0% +sort of spectrum between a lot of small +firms beating each other's brains out + + align:start position:0% +firms beating each other's brains out + + + align:start position:0% +firms beating each other's brains out +and one Monopoly taking everything there + + align:start position:0% +and one Monopoly taking everything there + + + align:start position:0% +and one Monopoly taking everything there +is to be had so this is one force that + + align:start position:0% +is to be had so this is one force that + + + align:start position:0% +is to be had so this is one force that +can affect competition can affect + + align:start position:0% +can affect competition can affect + + + align:start position:0% +can affect competition can affect +profits is the intensity of competition + + align:start position:0% +profits is the intensity of competition + + + align:start position:0% +profits is the intensity of competition +within the + + align:start position:0% +within the + + + align:start position:0% +within the +industry another + + align:start position:0% +industry another + + + align:start position:0% +industry another +force is the existence of close + + align:start position:0% +force is the existence of close + + + align:start position:0% +force is the existence of close +substitutes we all make wax paper and + + align:start position:0% +substitutes we all make wax paper and + + + align:start position:0% +substitutes we all make wax paper and +we're great wax paper manufacturers but + + align:start position:0% +we're great wax paper manufacturers but + + + align:start position:0% +we're great wax paper manufacturers but +you know plastic wrap is eating our + + align:start position:0% +you know plastic wrap is eating our + + + align:start position:0% +you know plastic wrap is eating our +lunch and so there may be only two or + + align:start position:0% +lunch and so there may be only two or + + + align:start position:0% +lunch and so there may be only two or +three of us making making wax paper but + + align:start position:0% +three of us making making wax paper but + + + align:start position:0% +three of us making making wax paper but +with the availability of cheap plastic + + align:start position:0% +with the availability of cheap plastic + + + align:start position:0% +with the availability of cheap plastic +wrap it means we have probably declining + + align:start position:0% +wrap it means we have probably declining + + + align:start position:0% +wrap it means we have probably declining +demand it means we probably have a + + align:start position:0% +demand it means we probably have a + + + align:start position:0% +demand it means we probably have a +highly elastic demand curve and even + + align:start position:0% +highly elastic demand curve and even + + + align:start position:0% +highly elastic demand curve and even +with a monopoly we can't make any money + + align:start position:0% +with a monopoly we can't make any money + + + align:start position:0% +with a monopoly we can't make any money +so close good substitutes erode + + align:start position:0% + + + + align:start position:0% + +profits I'm a w please have at it I'm a + + align:start position:0% +profits I'm a w please have at it I'm a + + + align:start position:0% +profits I'm a w please have at it I'm a +wax paper manufacturer there's only one + + align:start position:0% +wax paper manufacturer there's only one + + + align:start position:0% +wax paper manufacturer there's only one +of me but anybody in his kid sister can + + align:start position:0% +of me but anybody in his kid sister can + + + align:start position:0% +of me but anybody in his kid sister can +make wax paper that's not quite right + + align:start position:0% +make wax paper that's not quite right + + + align:start position:0% +make wax paper that's not quite right +and it could be his kid brother too + + align:start position:0% +and it could be his kid brother too + + + align:start position:0% +and it could be his kid brother too +don't mean to be sexist but but if it's + + align:start position:0% +don't mean to be sexist but but if it's + + + align:start position:0% +don't mean to be sexist but but if it's +really easy for competitors to come in + + align:start position:0% +really easy for competitors to come in + + + align:start position:0% +really easy for competitors to come in +if anybody's making any money nobody's + + align:start position:0% +if anybody's making any money nobody's + + + align:start position:0% +if anybody's making any money nobody's +going to can sustain it can sustain High + + align:start position:0% +going to can sustain it can sustain High + + + align:start position:0% +going to can sustain it can sustain High +profits so you look at entry when you do + + align:start position:0% +profits so you look at entry when you do + + + align:start position:0% +profits so you look at entry when you do +an industry analysis is it easy for + + align:start position:0% +an industry analysis is it easy for + + + align:start position:0% +an industry analysis is it easy for +Outsiders to come in what are the + + align:start position:0% +Outsiders to come in what are the + + + align:start position:0% +Outsiders to come in what are the +obstacles do you need specialized n know + + align:start position:0% +obstacles do you need specialized n know + + + align:start position:0% +obstacles do you need specialized n know +do you need huge capital what's what are + + align:start position:0% +do you need huge capital what's what are + + + align:start position:0% +do you need huge capital what's what are +the problems if there aren't any obvious + + align:start position:0% +the problems if there aren't any obvious + + + align:start position:0% +the problems if there aren't any obvious +barriers we're making Furniture in North + + align:start position:0% +barriers we're making Furniture in North + + + align:start position:0% +barriers we're making Furniture in North +Carolina what do you need to make + + align:start position:0% +Carolina what do you need to make + + + align:start position:0% +Carolina what do you need to make +furniture in North Carolina you need to + + align:start position:0% +furniture in North Carolina you need to + + + align:start position:0% +furniture in North Carolina you need to +hire good carpenters and get a supply of + + align:start position:0% +hire good carpenters and get a supply of + + + align:start position:0% +hire good carpenters and get a supply of +wood and have some design skill are + + align:start position:0% +wood and have some design skill are + + + align:start position:0% +wood and have some design skill are +those High barriers to entry probably + + align:start position:0% +those High barriers to entry probably + + + align:start position:0% +those High barriers to entry probably +not so would you expect even if they're + + align:start position:0% +not so would you expect even if they're + + + align:start position:0% +not so would you expect even if they're +only a small number of furniture + + align:start position:0% +only a small number of furniture + + + align:start position:0% +only a small number of furniture +manufacturers would you expect them to + + align:start position:0% +manufacturers would you expect them to + + + align:start position:0% +manufacturers would you expect them to +make a lot of money probably not + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +suppliers um my favorite example here + + align:start position:0% +suppliers um my favorite example here + + + align:start position:0% +suppliers um my favorite example here +really is + + align:start position:0% +really is + + + align:start position:0% +really is +Airlines um because one of the things + + align:start position:0% +Airlines um because one of the things + + + align:start position:0% +Airlines um because one of the things +that characterized Airlines particularly + + align:start position:0% +that characterized Airlines particularly + + + align:start position:0% +that characterized Airlines particularly +under regulation is very strong + + align:start position:0% +under regulation is very strong + + + align:start position:0% +under regulation is very strong +unions so while the airlines didn't make + + align:start position:0% +unions so while the airlines didn't make + + + align:start position:0% +unions so while the airlines didn't make +any + + align:start position:0% +any + + + align:start position:0% +any +money Airline employees + + align:start position:0% +money Airline employees + + + align:start position:0% +money Airline employees +did Pilots earn very high salaries for + + align:start position:0% +did Pilots earn very high salaries for + + + align:start position:0% +did Pilots earn very high salaries for +relatively little work flight attendant + + align:start position:0% +relatively little work flight attendant + + + align:start position:0% +relatively little work flight attendant +is this is again in the days of + + align:start position:0% +is this is again in the days of + + + align:start position:0% +is this is again in the days of +Regulation flight attendants earned very + + align:start position:0% +Regulation flight attendants earned very + + + align:start position:0% +Regulation flight attendants earned very +high salaries The Regulators pushed + + align:start position:0% +high salaries The Regulators pushed + + + align:start position:0% +high salaries The Regulators pushed +prices up and most of the rent most of + + align:start position:0% +prices up and most of the rent most of + + + align:start position:0% +prices up and most of the rent most of +the profit went down here to the + + align:start position:0% +the profit went down here to the + + + align:start position:0% +the profit went down here to the +unionized suppliers because there was + + align:start position:0% +unionized suppliers because there was + + + align:start position:0% +unionized suppliers because there was +pretty heavy competition up here so you + + align:start position:0% +pretty heavy competition up here so you + + + align:start position:0% +pretty heavy competition up here so you +had competition here the ability here to + + align:start position:0% +had competition here the ability here to + + + align:start position:0% +had competition here the ability here to +earn rent you see this in a lot of + + align:start position:0% +earn rent you see this in a lot of + + + align:start position:0% +earn rent you see this in a lot of +Industries where there's relatively + + align:start position:0% +Industries where there's relatively + + + align:start position:0% +Industries where there's relatively +little competition in the industry + + align:start position:0% +little competition in the industry + + + align:start position:0% +little competition in the industry +competition within the industry Subs + + align:start position:0% +competition within the industry Subs + + + align:start position:0% +competition within the industry Subs +inutes buyers entrance + + align:start position:0% +inutes buyers entrance + + + align:start position:0% +inutes buyers entrance +suppliers is injection molding a good + + align:start position:0% +suppliers is injection molding a good + + + align:start position:0% +suppliers is injection molding a good +business to be in in 1995 Julian why + + align:start position:0% +business to be in in 1995 Julian why + + + align:start position:0% +business to be in in 1995 Julian why +not because China does it cheaper well + + align:start position:0% +not because China does it cheaper well + + + align:start position:0% +not because China does it cheaper well +not in 1995 they didn't uh we're talking + + align:start position:0% +not in 1995 they didn't uh we're talking + + + align:start position:0% +not in 1995 they didn't uh we're talking +let's stay within the let's stay within + + align:start position:0% +let's stay within the let's stay within + + + align:start position:0% +let's stay within the let's stay within +the bounds of the case if we can um + + align:start position:0% +the bounds of the case if we can um + + + align:start position:0% +the bounds of the case if we can um +anybody else Charlotte um no because at + + align:start position:0% +anybody else Charlotte um no because at + + + align:start position:0% +anybody else Charlotte um no because at +that point competitors are figuring out + + align:start position:0% +that point competitors are figuring out + + + align:start position:0% +that point competitors are figuring out +ways to do things cheaper and to charge + + align:start position:0% +ways to do things cheaper and to charge + + + align:start position:0% +ways to do things cheaper and to charge +less money and then also because the + + align:start position:0% +less money and then also because the + + + align:start position:0% +less money and then also because the +buyers were these people using the + + align:start position:0% +buyers were these people using the + + + align:start position:0% +buyers were these people using the +machines that they were making and the + + align:start position:0% +machines that they were making and the + + + align:start position:0% +machines that they were making and the +the uh materials they needed were in + + align:start position:0% +the uh materials they needed were in + + + align:start position:0% +the uh materials they needed were in +high demand so the prices were going up + + align:start position:0% +high demand so the prices were going up + + + align:start position:0% +high demand so the prices were going up +that's the that's the resin we we'll + + align:start position:0% +that's the that's the resin we we'll + + + align:start position:0% +that's the that's the resin we we'll +come to that but this thing you're + + align:start position:0% +come to that but this thing you're + + + align:start position:0% +come to that but this thing you're +you're saying there just a lot going on + + align:start position:0% +you're saying there just a lot going on + + + align:start position:0% +you're saying there just a lot going on +here within the industry very intense + + align:start position:0% +here within the industry very intense + + + align:start position:0% +here within the industry very intense +competition uh what's interesting about + + align:start position:0% +competition uh what's interesting about + + + align:start position:0% +competition uh what's interesting about +this is that's right + + align:start position:0% +this is that's right + + + align:start position:0% +this is that's right +uh it doesn't look like most of that + + align:start position:0% +uh it doesn't look like most of that + + + align:start position:0% +uh it doesn't look like most of that +industry is very attractive even though + + align:start position:0% +industry is very attractive even though + + + align:start position:0% +industry is very attractive even though +it's growing like + + align:start position:0% +it's growing like + + + align:start position:0% +it's growing like +crazy the industry is growing like crazy + + align:start position:0% +crazy the industry is growing like crazy + + + align:start position:0% +crazy the industry is growing like crazy +it's a great example of everybody having + + align:start position:0% +it's a great example of everybody having + + + align:start position:0% +it's a great example of everybody having +to run fast to stay in the same place + + align:start position:0% +to run fast to stay in the same place + + + align:start position:0% +to run fast to stay in the same place +right because there's a lot of + + align:start position:0% +right because there's a lot of + + + align:start position:0% +right because there's a lot of +innovation as Charlotte says and if + + align:start position:0% +innovation as Charlotte says and if + + + align:start position:0% +innovation as Charlotte says and if +you're not doing it you + + align:start position:0% +you're not doing it you + + + align:start position:0% +you're not doing it you +lose so industries that look like that + + align:start position:0% +lose so industries that look like that + + + align:start position:0% +lose so industries that look like that +are not uncommon you think about the + + align:start position:0% +are not uncommon you think about the + + + align:start position:0% +are not uncommon you think about the +early day again Warren Buffett the early + + align:start position:0% +early day again Warren Buffett the early + + + align:start position:0% +early day again Warren Buffett the early +days of + + align:start position:0% +days of + + + align:start position:0% +days of +automobiles there were hundreds of + + align:start position:0% +automobiles there were hundreds of + + + align:start position:0% +automobiles there were hundreds of +people + + align:start position:0% +people + + + align:start position:0% +people +Automobiles and they were all making + + align:start position:0% +Automobiles and they were all making + + + align:start position:0% +Automobiles and they were all making +great progress and innovating like crazy + + align:start position:0% +great progress and innovating like crazy + + + align:start position:0% +great progress and innovating like crazy +and automobile sales were taking off + + align:start position:0% +and automobile sales were taking off + + + align:start position:0% +and automobile sales were taking off +like a rocket and most of them + + align:start position:0% +like a rocket and most of them + + + align:start position:0% +like a rocket and most of them +died because they were offering more or + + align:start position:0% +died because they were offering more or + + + align:start position:0% +died because they were offering more or +less the same kind of product doing more + + align:start position:0% +less the same kind of product doing more + + + align:start position:0% +less the same kind of product doing more +or less the same things as everybody + + align:start position:0% +or less the same things as everybody + + + align:start position:0% +or less the same things as everybody +else and had to run to keep in place + + align:start position:0% +else and had to run to keep in place + + + align:start position:0% +else and had to run to keep in place +so I think in terms of we worry a little + + align:start position:0% +so I think in terms of we worry a little + + + align:start position:0% +so I think in terms of we worry a little +bit about we hear a little bit about + + align:start position:0% +bit about we hear a little bit about + + + align:start position:0% +bit about we hear a little bit about +buyers only a little bit one of the big + + align:start position:0% +buyers only a little bit one of the big + + + align:start position:0% +buyers only a little bit one of the big +uh bottl makers is mentioned as a as a + + align:start position:0% +uh bottl makers is mentioned as a as a + + + align:start position:0% +uh bottl makers is mentioned as a as a +powerful buyer we don't know much about + + align:start position:0% +powerful buyer we don't know much about + + + align:start position:0% +powerful buyer we don't know much about +that substitutes we seem to be pretty + + align:start position:0% +that substitutes we seem to be pretty + + + align:start position:0% +that substitutes we seem to be pretty +good this looks like an industry people + + align:start position:0% +good this looks like an industry people + + + align:start position:0% +good this looks like an industry people +can enter this does not look like a high + + align:start position:0% +can enter this does not look like a high + + + align:start position:0% +can enter this does not look like a high +barrier industry we're not told much + + align:start position:0% +barrier industry we're not told much + + + align:start position:0% +barrier industry we're not told much +about that but we don't see much of a + + align:start position:0% +about that but we don't see much of a + + + align:start position:0% +about that but we don't see much of a +problem there there seem to be lots of + + align:start position:0% +problem there there seem to be lots of + + + align:start position:0% +problem there there seem to be lots of +mold makers and lots of suppliers of + + align:start position:0% +mold makers and lots of suppliers of + + + align:start position:0% +mold makers and lots of suppliers of +components so we don't seem to have a + + align:start position:0% +components so we don't seem to have a + + + align:start position:0% +components so we don't seem to have a +problem here the real problem in this + + align:start position:0% +problem here the real problem in this + + + align:start position:0% +problem here the real problem in this +industry is here where there's just very + + align:start position:0% +industry is here where there's just very + + + align:start position:0% +industry is here where there's just very +intense competition + + align:start position:0% +intense competition + + + align:start position:0% +intense competition +I even though there's high growth even + + align:start position:0% +I even though there's high growth even + + + align:start position:0% +I even though there's high growth even +though there's Innovation everybody's + + align:start position:0% +though there's Innovation everybody's + + + align:start position:0% +though there's Innovation everybody's +innovating everybody's moving and + + align:start position:0% +innovating everybody's moving and + + + align:start position:0% +innovating everybody's moving and +everybody's running very fast to stay in + + align:start position:0% +everybody's running very fast to stay in + + + align:start position:0% +everybody's running very fast to stay in +the same + + align:start position:0% +the same + + + align:start position:0% +the same +place so how do you beat this well let + + align:start position:0% +place so how do you beat this well let + + + align:start position:0% +place so how do you beat this well let +me talk generically and then we'll then + + align:start position:0% +me talk generically and then we'll then + + + align:start position:0% +me talk generically and then we'll then +we'll go to + + align:start position:0% +we'll go to + + + align:start position:0% +we'll go to +husky so + + align:start position:0% +husky so + + + align:start position:0% +husky so +generically + + align:start position:0% +generically + + + align:start position:0% +generically +um stepping way back you've got to both + + align:start position:0% +um stepping way back you've got to both + + + align:start position:0% +um stepping way back you've got to both +create value and and capture it so the + + align:start position:0% +create value and and capture it so the + + + align:start position:0% +create value and and capture it so the +if you think + + align:start position:0% +if you think + + + align:start position:0% +if you think +about oh + + align:start position:0% +about oh + + + align:start position:0% +about oh +suppliers what would you get for + + align:start position:0% +suppliers what would you get for + + + align:start position:0% +suppliers what would you get for +airplanes and aircraft Personnel uh uh + + align:start position:0% +airplanes and aircraft Personnel uh uh + + + align:start position:0% +airplanes and aircraft Personnel uh uh +sorry Airline + + align:start position:0% +sorry Airline + + + align:start position:0% +sorry Airline +Personnel how what would you have to pay + + align:start position:0% +Personnel how what would you have to pay + + + align:start position:0% +Personnel how what would you have to pay +to get a pilot to fly as opposed to what + + align:start position:0% +to get a pilot to fly as opposed to what + + + align:start position:0% +to get a pilot to fly as opposed to what +you do pay to get a pilot to fly again + + align:start position:0% +you do pay to get a pilot to fly again + + + align:start position:0% +you do pay to get a pilot to fly again +in the in the great old days of of + + align:start position:0% +in the in the great old days of of + + + align:start position:0% +in the in the great old days of of +limited competition there's there may be + + align:start position:0% +limited competition there's there may be + + + align:start position:0% +limited competition there's there may be +there may well be a gap between the + + align:start position:0% +there may well be a gap between the + + + align:start position:0% +there may well be a gap between the +suppliers opportunity cost what else + + align:start position:0% +suppliers opportunity cost what else + + + align:start position:0% +suppliers opportunity cost what else +could they do with their capital labor + + align:start position:0% +could they do with their capital labor + + + align:start position:0% +could they do with their capital labor +and what they sell for that's captured + + align:start position:0% +and what they sell for that's captured + + + align:start position:0% +and what they sell for that's captured +by the + + align:start position:0% +by the + + + align:start position:0% +by the +supplier there better be some gap + + align:start position:0% +supplier there better be some gap + + + align:start position:0% +supplier there better be some gap +between what buyers are willingness to + + align:start position:0% +between what buyers are willingness to + + + align:start position:0% +between what buyers are willingness to +pay and buyers are willing to + + align:start position:0% +pay and buyers are willing to + + + align:start position:0% +pay and buyers are willing to +pay uh and what they actually + + align:start position:0% +pay uh and what they actually + + + align:start position:0% +pay uh and what they actually +pay and the difference is what you get + + align:start position:0% +pay and the difference is what you get + + + align:start position:0% +pay and the difference is what you get +to take home the difference between what + + align:start position:0% +to take home the difference between what + + + align:start position:0% +to take home the difference between what +it actually costs you and what you can + + align:start position:0% +it actually costs you and what you can + + + align:start position:0% +it actually costs you and what you can +sell that this is like yeah this is + + align:start position:0% +sell that this is like yeah this is + + + align:start position:0% +sell that this is like yeah this is +pretty straightforward and pretty + + align:start position:0% +pretty straightforward and pretty + + + align:start position:0% +pretty straightforward and pretty +obvious but you really do need to think + + align:start position:0% +obvious but you really do need to think + + + align:start position:0% +obvious but you really do need to think +through and I love the animation you do + + align:start position:0% +through and I love the animation you do + + + align:start position:0% +through and I love the animation you do +need to think + + align:start position:0% +need to think + + + align:start position:0% +need to think +through who captures it if you go to the + + align:start position:0% +through who captures it if you go to the + + + align:start position:0% +through who captures it if you go to the +airlines there's + + align:start position:0% +airlines there's + + + align:start position:0% +airlines there's +enormous value created by the airline + + align:start position:0% +enormous value created by the airline + + + align:start position:0% +enormous value created by the airline +industry historically imagine it going + + align:start position:0% +industry historically imagine it going + + + align:start position:0% +industry historically imagine it going +away it's not captured by and large by + + align:start position:0% +away it's not captured by and large by + + + align:start position:0% +away it's not captured by and large by +the airline + + align:start position:0% +the airline + + + align:start position:0% +the airline +companies where does it go well with the + + align:start position:0% +companies where does it go well with the + + + align:start position:0% +companies where does it go well with the +decline of Airline unions less of it + + align:start position:0% +decline of Airline unions less of it + + + align:start position:0% +decline of Airline unions less of it +gets captured by + + align:start position:0% +gets captured by + + + align:start position:0% +gets captured by +suppliers and more of it's captured by + + align:start position:0% +suppliers and more of it's captured by + + + align:start position:0% +suppliers and more of it's captured by +us right if you think about the + + align:start position:0% +us right if you think about the + + + align:start position:0% +us right if you think about the +alternative way + + align:start position:0% +alternative way + + + align:start position:0% +alternative way +of I was in Florida last week and + + align:start position:0% +of I was in Florida last week and + + + align:start position:0% +of I was in Florida last week and +driving to Florida which I have done is + + align:start position:0% +driving to Florida which I have done is + + + align:start position:0% +driving to Florida which I have done is +not much fun so I'd be willing I would + + align:start position:0% +not much fun so I'd be willing I would + + + align:start position:0% +not much fun so I'd be willing I would +have been willing to spend a lot more + + align:start position:0% +have been willing to spend a lot more + + + align:start position:0% +have been willing to spend a lot more +than it cost me uh to fly I I got a huge + + align:start position:0% +than it cost me uh to fly I I got a huge + + + align:start position:0% +than it cost me uh to fly I I got a huge +Surplus um I don't have the impression + + align:start position:0% +Surplus um I don't have the impression + + + align:start position:0% +Surplus um I don't have the impression +that the folks supplying the airline + + align:start position:0% +that the folks supplying the airline + + + align:start position:0% +that the folks supplying the airline +were getting a lot of money and I know + + align:start position:0% +were getting a lot of money and I know + + + align:start position:0% +were getting a lot of money and I know +the airline wasn't getting much in terms + + align:start position:0% +the airline wasn't getting much in terms + + + align:start position:0% +the airline wasn't getting much in terms +of captured Surplus so the basic + + align:start position:0% +of captured Surplus so the basic + + + align:start position:0% +of captured Surplus so the basic +strategic question is in any kind of + + align:start position:0% +strategic question is in any kind of + + + align:start position:0% +strategic question is in any kind of +industry attractive or + + align:start position:0% +industry attractive or + + + align:start position:0% +industry attractive or +unattractive can you do + + align:start position:0% +unattractive can you do + + + align:start position:0% +unattractive can you do +this so where Porter is pointing and + + align:start position:0% +this so where Porter is pointing and + + + align:start position:0% +this so where Porter is pointing and +where this case points + + align:start position:0% +where this case points + + + align:start position:0% +where this case points +us is to ways to not do the same thing + + align:start position:0% +us is to ways to not do the same thing + + + align:start position:0% +us is to ways to not do the same thing +your competitors are + + align:start position:0% +your competitors are + + + align:start position:0% +your competitors are +doing what can we do + + align:start position:0% +doing what can we do + + + align:start position:0% +doing what can we do +differently well the first basic this is + + align:start position:0% +differently well the first basic this is + + + align:start position:0% +differently well the first basic this is +sort of the Southwest + + align:start position:0% +sort of the Southwest + + + align:start position:0% +sort of the Southwest +strategy this says we are going to drive + + align:start position:0% +strategy this says we are going to drive + + + align:start position:0% +strategy this says we are going to drive +down costs + + align:start position:0% +down costs + + + align:start position:0% +down costs +and in a way that's hard to imitate + + align:start position:0% +and in a way that's hard to imitate + + + align:start position:0% +and in a way that's hard to imitate +we'll talk about what makes it hard to + + align:start position:0% +we'll talk about what makes it hard to + + + align:start position:0% +we'll talk about what makes it hard to +imitate we're going to drive down costs + + align:start position:0% +imitate we're going to drive down costs + + + align:start position:0% +imitate we're going to drive down costs +and maybe we Supply a somewhat different + + align:start position:0% +and maybe we Supply a somewhat different + + + align:start position:0% +and maybe we Supply a somewhat different +product southwest's product is not very + + align:start position:0% +product southwest's product is not very + + + align:start position:0% +product southwest's product is not very +useful for somebody who not very + + align:start position:0% +useful for somebody who not very + + + align:start position:0% +useful for somebody who not very +interesting to somebody who always flies + + align:start position:0% +interesting to somebody who always flies + + + align:start position:0% +interesting to somebody who always flies +first class and cares about it they + + align:start position:0% +first class and cares about it they + + + align:start position:0% +first class and cares about it they +don't do first class they've written + + align:start position:0% +don't do first class they've written + + + align:start position:0% +don't do first class they've written +that off they've written off they don't + + align:start position:0% +that off they've written off they don't + + + align:start position:0% +that off they've written off they don't +do frequent flyer I don't think maybe + + align:start position:0% +do frequent flyer I don't think maybe + + + align:start position:0% +do frequent flyer I don't think maybe +they do but but for a whole set of + + align:start position:0% +they do but but for a whole set of + + + align:start position:0% +they do but but for a whole set of +business Travelers they're not that + + align:start position:0% +business Travelers they're not that + + + align:start position:0% +business Travelers they're not that +attractive + + align:start position:0% +attractive + + + align:start position:0% +attractive +they're cheap yeah but if somebody else + + align:start position:0% +they're cheap yeah but if somebody else + + + align:start position:0% +they're cheap yeah but if somebody else +is paying my airfare that's not too + + align:start position:0% +is paying my airfare that's not too + + + align:start position:0% +is paying my airfare that's not too +attractive they're not convenient + + align:start position:0% +attractive they're not convenient + + + align:start position:0% +attractive they're not convenient +because I can't book online think about + + align:start position:0% +because I can't book online think about + + + align:start position:0% +because I can't book online think about +my own travel usually somebody else is + + align:start position:0% +my own travel usually somebody else is + + + align:start position:0% +my own travel usually somebody else is +paying and I book online for Simplicity + + align:start position:0% +paying and I book online for Simplicity + + + align:start position:0% +paying and I book online for Simplicity +I never fly + + align:start position:0% +I never fly + + + align:start position:0% +I never fly +Southwest because the fair difference + + align:start position:0% +Southwest because the fair difference + + + align:start position:0% +Southwest because the fair difference +doesn't bother the people who are paying + + align:start position:0% +doesn't bother the people who are paying + + + align:start position:0% +doesn't bother the people who are paying +my airfare and online booking is so + + align:start position:0% +my airfare and online booking is so + + + align:start position:0% +my airfare and online booking is so +enormously convenient that I just do it + + align:start position:0% +enormously convenient that I just do it + + + align:start position:0% +enormously convenient that I just do it +so I'm not in their I'm not in the set + + align:start position:0% +so I'm not in their I'm not in the set + + + align:start position:0% +so I'm not in their I'm not in the set +of consumers they're aiming at so what + + align:start position:0% +of consumers they're aiming at so what + + + align:start position:0% +of consumers they're aiming at so what +there are enough of them there are + + align:start position:0% +there are enough of them there are + + + align:start position:0% +there are enough of them there are +enough people and enough travel + + align:start position:0% +enough people and enough travel + + + align:start position:0% +enough people and enough travel +occasions and I could imagine occasions + + align:start position:0% +occasions and I could imagine occasions + + + align:start position:0% +occasions and I could imagine occasions +when I would I would check Southwest + + align:start position:0% +when I would I would check Southwest + + + align:start position:0% +when I would I would check Southwest +just to see if they're + + align:start position:0% +just to see if they're + + + align:start position:0% +just to see if they're +cheaper that's a that's a strategy the + + align:start position:0% +cheaper that's a that's a strategy the + + + align:start position:0% +cheaper that's a that's a strategy the +the issue + + align:start position:0% +the issue + + + align:start position:0% +the issue +there is what makes it hard to + + align:start position:0% +there is what makes it hard to + + + align:start position:0% +there is what makes it hard to +imitate what makes it hard to imitate as + + align:start position:0% +imitate what makes it hard to imitate as + + + align:start position:0% +imitate what makes it hard to imitate as +Charlotte pointed out in the injection + + align:start position:0% +Charlotte pointed out in the injection + + + align:start position:0% +Charlotte pointed out in the injection +molding business everybody's everybody's + + align:start position:0% +molding business everybody's everybody's + + + align:start position:0% +molding business everybody's everybody's +innovating so and in the airline + + align:start position:0% +innovating so and in the airline + + + align:start position:0% +innovating so and in the airline +business business everybody does + + align:start position:0% +business business everybody does + + + align:start position:0% +business business everybody does +electronic reservations and everybody + + align:start position:0% +electronic reservations and everybody + + + align:start position:0% +electronic reservations and everybody +does this and everybody does that lots + + align:start position:0% +does this and everybody does that lots + + + align:start position:0% +does this and everybody does that lots +of + + align:start position:0% +of + + + align:start position:0% +of +innovation everybody driving down costs + + align:start position:0% +innovation everybody driving down costs + + + align:start position:0% +innovation everybody driving down costs +more fuel efficient engines no barriers + + align:start position:0% +more fuel efficient engines no barriers + + + align:start position:0% +more fuel efficient engines no barriers +to + + align:start position:0% +to + + + align:start position:0% +to +imitation United can copy what American + + align:start position:0% +imitation United can copy what American + + + align:start position:0% +imitation United can copy what American +does American can copy what United + + align:start position:0% +does American can copy what United + + + align:start position:0% +does American can copy what United +does there are seminars on industry best + + align:start position:0% +does there are seminars on industry best + + + align:start position:0% +does there are seminars on industry best +practice everybody does industry best + + align:start position:0% +practice everybody does industry best + + + align:start position:0% +practice everybody does industry best +practice you don't make any money doing + + align:start position:0% +practice you don't make any money doing + + + align:start position:0% +practice you don't make any money doing +industry best practice you may avoid + + align:start position:0% +industry best practice you may avoid + + + align:start position:0% +industry best practice you may avoid +losing money so that's Strate + + align:start position:0% +losing money so that's Strate + + + align:start position:0% +losing money so that's Strate +one can I somehow get low costs and I + + align:start position:0% +one can I somehow get low costs and I + + + align:start position:0% +one can I somehow get low costs and I +highlight this some + + align:start position:0% +highlight this some + + + align:start position:0% +highlight this some +consumers because Southwest and Ikea are + + align:start position:0% +consumers because Southwest and Ikea are + + + align:start position:0% +consumers because Southwest and Ikea are +nice examples of picking a piece of the + + align:start position:0% +nice examples of picking a piece of the + + + align:start position:0% +nice examples of picking a piece of the +market which a lowcost strategy makes + + align:start position:0% +market which a lowcost strategy makes + + + align:start position:0% +market which a lowcost strategy makes +sense not everybody goes to + + align:start position:0% +sense not everybody goes to + + + align:start position:0% +sense not everybody goes to +Ikea I've never been in an Ikea as it + + align:start position:0% +Ikea I've never been in an Ikea as it + + + align:start position:0% +Ikea I've never been in an Ikea as it +happens um but but uh lots of people do + + align:start position:0% +happens um but but uh lots of people do + + + align:start position:0% +happens um but but uh lots of people do +and that's enough to make them a lot of + + align:start position:0% +and that's enough to make them a lot of + + + align:start position:0% +and that's enough to make them a lot of +money the other strategy not too + + align:start position:0% +money the other strategy not too + + + align:start position:0% +money the other strategy not too +surprisingly is to go the other + + align:start position:0% +surprisingly is to go the other + + + align:start position:0% +surprisingly is to go the other +direction is to find a way to increase + + align:start position:0% +direction is to find a way to increase + + + align:start position:0% +direction is to find a way to increase +perceived quality willingness to pay for + + align:start position:0% +perceived quality willingness to pay for + + + align:start position:0% +perceived quality willingness to pay for +some + + align:start position:0% +some + + + align:start position:0% +some +buyers to justify higher + + align:start position:0% +buyers to justify higher + + + align:start position:0% +buyers to justify higher +prices what can we do to justify higher + + align:start position:0% +prices what can we do to justify higher + + + align:start position:0% +prices what can we do to justify higher +prices and + + align:start position:0% +prices and + + + align:start position:0% +prices and +again they're examples right + + align:start position:0% +again they're examples right + + + align:start position:0% +again they're examples right +Mercedes-Benz is a high quality they + + align:start position:0% +Mercedes-Benz is a high quality they + + + align:start position:0% +Mercedes-Benz is a high quality they +don't do the same thing that everybody + + align:start position:0% +don't do the same thing that everybody + + + align:start position:0% +don't do the same thing that everybody +else does not the same kind of car it + + align:start position:0% +else does not the same kind of car it + + + align:start position:0% +else does not the same kind of car it +costs more it absolutely costs more this + + align:start position:0% +costs more it absolutely costs more this + + + align:start position:0% +costs more it absolutely costs more this +in this example the costs are the same + + align:start position:0% +in this example the costs are the same + + + align:start position:0% +in this example the costs are the same +but you know you could still make a lot + + align:start position:0% +but you know you could still make a lot + + + align:start position:0% +but you know you could still make a lot +of money if those costs are a little + + align:start position:0% +of money if those costs are a little + + + align:start position:0% +of money if those costs are a little +higher as long + + align:start position:0% +higher as long + + + align:start position:0% +higher as long +as the differentiation is + + align:start position:0% +as the differentiation is + + + align:start position:0% +as the differentiation is +effective so this kind of strategy you + + align:start position:0% +effective so this kind of strategy you + + + align:start position:0% +effective so this kind of strategy you +pick + + align:start position:0% +pick + + + align:start position:0% +pick +something that somebody + + align:start position:0% +something that somebody + + + align:start position:0% +something that somebody +values um actually the online booking + + align:start position:0% +values um actually the online booking + + + align:start position:0% +values um actually the online booking +system well not not quite that's an + + align:start position:0% +system well not not quite that's an + + + align:start position:0% +system well not not quite that's an +interesting story um you meet the needs + + align:start position:0% +interesting story um you meet the needs + + + align:start position:0% +interesting story um you meet the needs +you add costs you get premium prices + + align:start position:0% +you add costs you get premium prices + + + align:start position:0% +you add costs you get premium prices +terrific + + align:start position:0% +terrific + + + align:start position:0% +terrific +story + + align:start position:0% +story + + + align:start position:0% +story +but it has to be cost effective that is + + align:start position:0% +but it has to be cost effective that is + + + align:start position:0% +but it has to be cost effective that is +to say you can raise the price but if + + align:start position:0% +to say you can raise the price but if + + + align:start position:0% +to say you can raise the price but if +your costs go up by more than the price + + align:start position:0% +your costs go up by more than the price + + + align:start position:0% +your costs go up by more than the price +you lose and you come down to the + + align:start position:0% +you lose and you come down to the + + + align:start position:0% +you lose and you come down to the +same issue is imitation difficult is + + align:start position:0% +same issue is imitation difficult is + + + align:start position:0% +same issue is imitation difficult is +imitation difficult again we see we're + + align:start position:0% +imitation difficult again we see we're + + + align:start position:0% +imitation difficult again we see we're +going to see this in husky is imitation + + align:start position:0% +going to see this in husky is imitation + + + align:start position:0% +going to see this in husky is imitation +difficult there's sort + + align:start position:0% + + + + align:start position:0% + +of nice diagram there's sort of three + + align:start position:0% +of nice diagram there's sort of three + + + align:start position:0% +of nice diagram there's sort of three +kinds of + + align:start position:0% +kinds of + + + align:start position:0% +kinds of +stories about ways that that imitation + + align:start position:0% +stories about ways that that imitation + + + align:start position:0% +stories about ways that that imitation +can be + + align:start position:0% +can be + + + align:start position:0% +can be +difficult the first is sort of the Ikea + + align:start position:0% +difficult the first is sort of the Ikea + + + align:start position:0% +difficult the first is sort of the Ikea +Southwest up on top the + + align:start position:0% +Southwest up on top the + + + align:start position:0% +Southwest up on top the +integration that if you have to build + + align:start position:0% +integration that if you have to build + + + align:start position:0% +integration that if you have to build +the company to deliver on a strategy + + align:start position:0% +the company to deliver on a strategy + + + align:start position:0% +the company to deliver on a strategy +effectively + + align:start position:0% +effectively + + + align:start position:0% +effectively +that's again in Porter the Southwest + + align:start position:0% +that's again in Porter the Southwest + + + align:start position:0% +that's again in Porter the Southwest +Airlines versus what was it Continental + + align:start position:0% +Airlines versus what was it Continental + + + align:start position:0% +Airlines versus what was it Continental +light so Continental decides they can + + align:start position:0% +light so Continental decides they can + + + align:start position:0% +light so Continental decides they can +compete with these lowcost carriers + + align:start position:0% +compete with these lowcost carriers + + + align:start position:0% +compete with these lowcost carriers +they'll offer a lowcost carrier they + + align:start position:0% +they'll offer a lowcost carrier they + + + align:start position:0% +they'll offer a lowcost carrier they +won't serve meals and they won't do + + align:start position:0% +won't serve meals and they won't do + + + align:start position:0% +won't serve meals and they won't do +assigned + + align:start position:0% +assigned + + + align:start position:0% +assigned +seats but they do baggage interchange + + align:start position:0% +seats but they do baggage interchange + + + align:start position:0% +seats but they do baggage interchange +with other airlines because they're + + align:start position:0% +with other airlines because they're + + + align:start position:0% +with other airlines because they're +Continental they do online booking + + align:start position:0% +Continental they do online booking + + + align:start position:0% +Continental they do online booking +because they're + + align:start position:0% +because they're + + + align:start position:0% +because they're +Continental they do a variety of other + + align:start position:0% +Continental they do a variety of other + + + align:start position:0% +Continental they do a variety of other +things because they're continental and + + align:start position:0% +things because they're continental and + + + align:start position:0% +things because they're continental and +they can't get the cost down that + + align:start position:0% +they can't get the cost down that + + + align:start position:0% +they can't get the cost down that +low to get the cost down that low you've + + align:start position:0% +low to get the cost down that low you've + + + align:start position:0% +low to get the cost down that low you've +got to integrate the whole thing you've + + align:start position:0% +got to integrate the whole thing you've + + + align:start position:0% +got to integrate the whole thing you've +got to build the you got to build an + + align:start position:0% +got to build the you got to build an + + + align:start position:0% +got to build the you got to build an +Ikea to deliver + + align:start position:0% +Ikea to deliver + + + align:start position:0% +Ikea to deliver +Ikea you can't have an Ikea tacked on to + + align:start position:0% +Ikea you can't have an Ikea tacked on to + + + align:start position:0% +Ikea you can't have an Ikea tacked on to +something + + align:start position:0% +something + + + align:start position:0% +something +else which means it's hard for an + + align:start position:0% +else which means it's hard for an + + + align:start position:0% +else which means it's hard for an +existing firm to copy the notion that + + align:start position:0% +existing firm to copy the notion that + + + align:start position:0% +existing firm to copy the notion that +you have to integrate the whole + + align:start position:0% +you have to integrate the whole + + + align:start position:0% +you have to integrate the whole +system + + align:start position:0% + + + + align:start position:0% + +um I guess another sort of example like + + align:start position:0% +um I guess another sort of example like + + + align:start position:0% +um I guess another sort of example like +that would be Jiffy Lube or one of the + + align:start position:0% +that would be Jiffy Lube or one of the + + + align:start position:0% +that would be Jiffy Lube or one of the +one of the uh quick lube places that + + align:start position:0% +one of the uh quick lube places that + + + align:start position:0% +one of the uh quick lube places that +used to you don't see them as much as + + align:start position:0% +used to you don't see them as much as + + + align:start position:0% +used to you don't see them as much as +you used to that offers cheap oil change + + align:start position:0% +you used to that offers cheap oil change + + + align:start position:0% +you used to that offers cheap oil change +that's all they do or all they did and + + align:start position:0% +that's all they do or all they did and + + + align:start position:0% +that's all they do or all they did and +could you imitate that yeah you could + + align:start position:0% +could you imitate that yeah you could + + + align:start position:0% +could you imitate that yeah you could +but you'd really have to have the + + align:start position:0% +but you'd really have to have the + + + align:start position:0% +but you'd really have to have the +company focused on doing just that you + + align:start position:0% +company focused on doing just that you + + + align:start position:0% +company focused on doing just that you +can't do cheap oil change as part of a a + + align:start position:0% +can't do cheap oil change as part of a a + + + align:start position:0% +can't do cheap oil change as part of a a +full service repair shop that does other + + align:start position:0% +full service repair shop that does other + + + align:start position:0% +full service repair shop that does other +things CU you got all that overhead and + + align:start position:0% +things CU you got all that overhead and + + + align:start position:0% +things CU you got all that overhead and +all of the systems that to handle + + align:start position:0% +all of the systems that to handle + + + align:start position:0% +all of the systems that to handle +everything if you just do oil change + + align:start position:0% +everything if you just do oil change + + + align:start position:0% +everything if you just do oil change +it's a simple business you could do it + + align:start position:0% +it's a simple business you could do it + + + align:start position:0% +it's a simple business you could do it +very cheaply if you do more you got to + + align:start position:0% +very cheaply if you do more you got to + + + align:start position:0% +very cheaply if you do more you got to +hire different people you got to have + + align:start position:0% +hire different people you got to have + + + align:start position:0% +hire different people you got to have +different systems you got to have + + align:start position:0% +different systems you got to have + + + align:start position:0% +different systems you got to have +different inventory so one reason it can + + align:start position:0% +different inventory so one reason it can + + + align:start position:0% +different inventory so one reason it can +be hard is that everything is integrated + + align:start position:0% +be hard is that everything is integrated + + + align:start position:0% +be hard is that everything is integrated +everything is integrated it would be + + align:start position:0% +everything is integrated it would be + + + align:start position:0% +everything is integrated it would be +hard well I interestingly enough if you + + align:start position:0% +hard well I interestingly enough if you + + + align:start position:0% +hard well I interestingly enough if you +think about General + + align:start position:0% +think about General + + + align:start position:0% +think about General +Motors uh + + align:start position:0% +Motors uh + + + align:start position:0% +Motors uh +historically Cadillac was focused on + + align:start position:0% +historically Cadillac was focused on + + + align:start position:0% +historically Cadillac was focused on +luxury cars and was sort of kept + + align:start position:0% +luxury cars and was sort of kept + + + align:start position:0% +luxury cars and was sort of kept +separate + + align:start position:0% +separate + + + align:start position:0% +separate +from the rest of GM in the glory years + + align:start position:0% +from the rest of GM in the glory years + + + align:start position:0% +from the rest of GM in the glory years +Cadillac delivered luxury cars you + + align:start position:0% +Cadillac delivered luxury cars you + + + align:start position:0% +Cadillac delivered luxury cars you +couldn't have the Cadillac operation + + align:start position:0% +couldn't have the Cadillac operation + + + align:start position:0% +couldn't have the Cadillac operation +closely integrated with the Chevrolet + + align:start position:0% +closely integrated with the Chevrolet + + + align:start position:0% +closely integrated with the Chevrolet +operation right you just you have + + align:start position:0% +operation right you just you have + + + align:start position:0% +operation right you just you have +different philosophies you have + + align:start position:0% +different philosophies you have + + + align:start position:0% +different philosophies you have +different purchasing you have different + + align:start position:0% +different purchasing you have different + + + align:start position:0% +different purchasing you have different +design approaches Cadillac everything + + align:start position:0% +design approaches Cadillac everything + + + align:start position:0% +design approaches Cadillac everything +was focused on a certain kind of + + align:start position:0% +was focused on a certain kind of + + + align:start position:0% +was focused on a certain kind of +car integrated built to + + align:start position:0% +car integrated built to + + + align:start position:0% +car integrated built to +deliver you'd have to build a system as + + align:start position:0% +deliver you'd have to build a system as + + + align:start position:0% +deliver you'd have to build a system as +many people did it turns out uh to + + align:start position:0% +many people did it turns out uh to + + + align:start position:0% +many people did it turns out uh to +compete the + + align:start position:0% +compete the + + + align:start position:0% +compete the +second there on the right a capture + + align:start position:0% +second there on the right a capture + + + align:start position:0% +second there on the right a capture +model is cost if you have a cost + + align:start position:0% +model is cost if you have a cost + + + align:start position:0% +model is cost if you have a cost +Advantage how can you have a cost + + align:start position:0% +Advantage how can you have a cost + + + align:start position:0% +Advantage how can you have a cost +Advantage well there might be economies + + align:start position:0% +Advantage well there might be economies + + + align:start position:0% +Advantage well there might be economies +of + + align:start position:0% +of + + + align:start position:0% +of +scale you might have learning advantages + + align:start position:0% +scale you might have learning advantages + + + align:start position:0% +scale you might have learning advantages +you might have other kinds of advantages + + align:start position:0% +you might have other kinds of advantages + + + align:start position:0% +you might have other kinds of advantages +there are lots of ways you can have an + + align:start position:0% +there are lots of ways you can have an + + + align:start position:0% +there are lots of ways you can have an +advantage in cost yeah + + align:start position:0% +advantage in cost yeah + + + align:start position:0% +advantage in cost yeah +Andrew I said a question regarding + + align:start position:0% +Andrew I said a question regarding + + + align:start position:0% +Andrew I said a question regarding +integration and these might be really + + align:start position:0% +integration and these might be really + + + align:start position:0% +integration and these might be really +examples I'm just curious where they fit + + align:start position:0% +examples I'm just curious where they fit + + + align:start position:0% +examples I'm just curious where they fit +in like uh company like Walmart or like + + align:start position:0% +in like uh company like Walmart or like + + + align:start position:0% +in like uh company like Walmart or like +Toyota that are like quite large scale + + align:start position:0% +Toyota that are like quite large scale + + + align:start position:0% +Toyota that are like quite large scale +but then again I've heard like many + + align:start position:0% +but then again I've heard like many + + + align:start position:0% +but then again I've heard like many +things about the way they for example + + align:start position:0% +things about the way they for example + + + align:start position:0% +things about the way they for example +for to Yota how they have like a uh like + + align:start position:0% +for to Yota how they have like a uh like + + + align:start position:0% +for to Yota how they have like a uh like +really integrated system from the + + align:start position:0% +really integrated system from the + + + align:start position:0% +really integrated system from the +supplier to like the end product and all + + align:start position:0% +supplier to like the end product and all + + + align:start position:0% +supplier to like the end product and all +the thing I was just curious are they + + align:start position:0% +the thing I was just curious are they + + + align:start position:0% +the thing I was just curious are they +like simply um uh like um exceptions or + + align:start position:0% +like simply um uh like um exceptions or + + + align:start position:0% +like simply um uh like um exceptions or +are they doing some other things also + + align:start position:0% +are they doing some other things also + + + align:start position:0% +are they doing some other things also +that I'm not seen well Toyota Toyota is + + align:start position:0% +that I'm not seen well Toyota Toyota is + + + align:start position:0% +that I'm not seen well Toyota Toyota is +a great case and others may know that + + align:start position:0% +a great case and others may know that + + + align:start position:0% +a great case and others may know that +system better than I do they combine a + + align:start position:0% +system better than I do they combine a + + + align:start position:0% +system better than I do they combine a +number of things but it is it is an + + align:start position:0% +number of things but it is it is an + + + align:start position:0% +number of things but it is it is an +example of a system built to do a couple + + align:start position:0% +example of a system built to do a couple + + + align:start position:0% +example of a system built to do a couple +of things well + + align:start position:0% +of things well + + + align:start position:0% +of things well +first + + align:start position:0% +first + + + align:start position:0% +first +um they built a product development + + align:start position:0% +um they built a product development + + + align:start position:0% +um they built a product development +system that was much quicker than + + align:start position:0% +system that was much quicker than + + + align:start position:0% +system that was much quicker than +American manufacturers and indeed much + + align:start position:0% +American manufacturers and indeed much + + + align:start position:0% +American manufacturers and indeed much +quicker than European manufacturers so + + align:start position:0% +quicker than European manufacturers so + + + align:start position:0% +quicker than European manufacturers so +they could go from concept to model on + + align:start position:0% +they could go from concept to model on + + + align:start position:0% +they could go from concept to model on +the street quicker so that's the + + align:start position:0% +the street quicker so that's the + + + align:start position:0% +the street quicker so that's the +Innovation speed down there in the + + align:start position:0% +Innovation speed down there in the + + + align:start position:0% +Innovation speed down there in the +left um could you imitate it a lot of + + align:start position:0% +left um could you imitate it a lot of + + + align:start position:0% +left um could you imitate it a lot of +people tried um there were no obvious + + align:start position:0% +people tried um there were no obvious + + + align:start position:0% +people tried um there were no obvious +barriers to imitating that they also had + + align:start position:0% +barriers to imitating that they also had + + + align:start position:0% +barriers to imitating that they also had +some some clever ways they did + + align:start position:0% +some some clever ways they did + + + align:start position:0% +some some clever ways they did +manufacturing just in time and the whole + + align:start position:0% +manufacturing just in time and the whole + + + align:start position:0% +manufacturing just in time and the whole +caman and quality circles there was a + + align:start position:0% +caman and quality circles there was a + + + align:start position:0% +caman and quality circles there was a +whole manufacturing + + align:start position:0% +whole manufacturing + + + align:start position:0% +whole manufacturing +system could you copy it well a lot of + + align:start position:0% +system could you copy it well a lot of + + + align:start position:0% +system could you copy it well a lot of +people + + align:start position:0% +people + + + align:start position:0% +people +tried and that's what's interesting + + align:start position:0% +tried and that's what's interesting + + + align:start position:0% +tried and that's what's interesting +right there was the there was the to + + align:start position:0% +right there was the there was the to + + + align:start position:0% +right there was the there was the to +Toyota General Motors joint venture that + + align:start position:0% +Toyota General Motors joint venture that + + + align:start position:0% +Toyota General Motors joint venture that +produced what was it that they produced + + align:start position:0% +produced what was it that they produced + + + align:start position:0% +produced what was it that they produced +in California new me yes and General + + align:start position:0% +in California new me yes and General + + + align:start position:0% +in California new me yes and General +Motors was going to learn the Toyota + + align:start position:0% +Motors was going to learn the Toyota + + + align:start position:0% +Motors was going to learn the Toyota +system and copy + + align:start position:0% +system and copy + + + align:start position:0% +system and copy +it well the cultures were different and + + align:start position:0% +it well the cultures were different and + + + align:start position:0% +it well the cultures were different and +the GM + + align:start position:0% +the GM + + + align:start position:0% +the GM +Workforce you know you've been doing + + align:start position:0% +Workforce you know you've been doing + + + align:start position:0% +Workforce you know you've been doing +something some way for 30 years and + + align:start position:0% +something some way for 30 years and + + + align:start position:0% +something some way for 30 years and +somebody says now we're going to do it + + align:start position:0% +somebody says now we're going to do it + + + align:start position:0% +somebody says now we're going to do it +this other + + align:start position:0% +this other + + + align:start position:0% +this other +way that's + + align:start position:0% +way that's + + + align:start position:0% +way that's +hard and you have to change the + + align:start position:0% +hard and you have to change the + + + align:start position:0% +hard and you have to change the +inventory control system and your + + align:start position:0% +inventory control system and your + + + align:start position:0% +inventory control system and your +purchasing system then you go to your + + align:start position:0% +purchasing system then you go to your + + + align:start position:0% +purchasing system then you go to your +designers and you got to change the + + align:start position:0% +designers and you got to change the + + + align:start position:0% +designers and you got to change the +speed at which you produce new products + + align:start position:0% +speed at which you produce new products + + + align:start position:0% +speed at which you produce new products +by changing that system I mean I'd say + + align:start position:0% +by changing that system I mean I'd say + + + align:start position:0% +by changing that system I mean I'd say +Toyota was successfully + + align:start position:0% +Toyota was successfully + + + align:start position:0% +Toyota was successfully +copied over a long time I wouldn't say + + align:start position:0% +copied over a long time I wouldn't say + + + align:start position:0% +copied over a long time I wouldn't say +GM has successfully copied them it + + align:start position:0% +GM has successfully copied them it + + + align:start position:0% +GM has successfully copied them it +wasn't that Toyota was bigger than + + align:start position:0% +wasn't that Toyota was bigger than + + + align:start position:0% +wasn't that Toyota was bigger than +anybody + + align:start position:0% +anybody + + + align:start position:0% +anybody +else they were doing a better job when + + align:start position:0% +else they were doing a better job when + + + align:start position:0% +else they were doing a better job when +they were smaller certainly smaller than + + align:start position:0% +they were smaller certainly smaller than + + + align:start position:0% +they were smaller certainly smaller than +the American companies so there + + align:start position:0% + + + + align:start position:0% + +there's an they got cost by developing a + + align:start position:0% +there's an they got cost by developing a + + + align:start position:0% +there's an they got cost by developing a +manufacturing and design system that was + + align:start position:0% +manufacturing and design system that was + + + align:start position:0% +manufacturing and design system that was +simply better and the advantage + + align:start position:0% +simply better and the advantage + + + align:start position:0% +simply better and the advantage +held because even though it looked like + + align:start position:0% +held because even though it looked like + + + align:start position:0% +held because even though it looked like +you could copy it and there were + + align:start position:0% +you could copy it and there were + + + align:start position:0% +you could copy it and there were +articles and books written on how you do + + align:start position:0% +articles and books written on how you do + + + align:start position:0% +articles and books written on how you do +the Toyota the Japanese system it turned + + align:start position:0% +the Toyota the Japanese system it turned + + + align:start position:0% +the Toyota the Japanese system it turned +out to be harder to put it in place + + align:start position:0% +out to be harder to put it in place + + + align:start position:0% +out to be harder to put it in place +because you had to do it all and again + + align:start position:0% +because you had to do it all and again + + + align:start position:0% +because you had to do it all and again +over time over time there are lots of + + align:start position:0% +over time over time there are lots of + + + align:start position:0% +over time over time there are lots of +studies where you see companies now that + + align:start position:0% +studies where you see companies now that + + + align:start position:0% +studies where you see companies now that +have that approach but it was + + align:start position:0% +have that approach but it was + + + align:start position:0% +have that approach but it was +sustainable and Toyota is in not in + + align:start position:0% +sustainable and Toyota is in not in + + + align:start position:0% +sustainable and Toyota is in not in +great shape uh it was it was um + + align:start position:0% +great shape uh it was it was um + + + align:start position:0% +great shape uh it was it was um +sustainable in part because of the fact + + align:start position:0% +sustainable in part because of the fact + + + align:start position:0% +sustainable in part because of the fact +that it was a system you had to do the + + align:start position:0% +that it was a system you had to do the + + + align:start position:0% +that it was a system you had to do the +whole thing you couldn't just Change + + align:start position:0% +whole thing you couldn't just Change + + + align:start position:0% +whole thing you couldn't just Change +inventory you couldn't just change + + align:start position:0% +inventory you couldn't just change + + + align:start position:0% +inventory you couldn't just change +design you had to take the whole thing + + align:start position:0% +design you had to take the whole thing + + + align:start position:0% +design you had to take the whole thing +and that meant bringing people along + + align:start position:0% +and that meant bringing people along + + + align:start position:0% +and that meant bringing people along +could you do a startup that way yeah + + align:start position:0% +could you do a startup that way yeah + + + align:start position:0% +could you do a startup that way yeah +much easier to do a startup much easier + + align:start position:0% +much easier to do a startup much easier + + + align:start position:0% +much easier to do a startup much easier +to take people who've never built or + + align:start position:0% +to take people who've never built or + + + align:start position:0% +to take people who've never built or +designed Automobiles and say here's how + + align:start position:0% +designed Automobiles and say here's how + + + align:start position:0% +designed Automobiles and say here's how +we're going to do it but then you've got + + align:start position:0% +we're going to do it but then you've got + + + align:start position:0% +we're going to do it but then you've got +a whole bunch of people who've never + + align:start position:0% +a whole bunch of people who've never + + + align:start position:0% +a whole bunch of people who've never +built or designed automobiles so so you + + align:start position:0% +built or designed automobiles so so you + + + align:start position:0% +built or designed automobiles so so you +know it's U it's a nice example thank + + align:start position:0% +know it's U it's a nice example thank + + + align:start position:0% +know it's U it's a nice example thank +you anything + + align:start position:0% +you anything + + + align:start position:0% +you anything +else any other + + align:start position:0% +else any other + + + align:start position:0% +else any other +comments + + align:start position:0% +comments + + + align:start position:0% +comments +okay let's do + + align:start position:0% +okay let's do + + + align:start position:0% +okay let's do +husky what's Husky's + + align:start position:0% +husky what's Husky's + + + align:start position:0% +husky what's Husky's +strategy what is it that we're 95 what + + align:start position:0% +strategy what is it that we're 95 what + + + align:start position:0% +strategy what is it that we're 95 what +is it historically husky wouldn't do + + align:start position:0% +is it historically husky wouldn't do + + + align:start position:0% +is it historically husky wouldn't do +Mary um so they Stu to several core + + align:start position:0% +Mary um so they Stu to several core + + + align:start position:0% +Mary um so they Stu to several core +values like perfectionism and dedicating + + align:start position:0% +values like perfectionism and dedicating + + + align:start position:0% +values like perfectionism and dedicating +to hard work and they also um devoted a + + align:start position:0% +to hard work and they also um devoted a + + + align:start position:0% +to hard work and they also um devoted a +lot of stuff to health and so that's a + + align:start position:0% +lot of stuff to health and so that's a + + + align:start position:0% +lot of stuff to health and so that's a +good description of the + + align:start position:0% +good description of the + + + align:start position:0% +good description of the +culture of how they went about doing + + align:start position:0% +culture of how they went about doing + + + align:start position:0% +culture of how they went about doing +what they did how did they what did they + + align:start position:0% +what they did how did they what did they + + + align:start position:0% +what they did how did they what did they +do what were their activities did they + + align:start position:0% +do what were their activities did they + + + align:start position:0% +do what were their activities did they +focus were they trying to do all kinds + + align:start position:0% +focus were they trying to do all kinds + + + align:start position:0% +focus were they trying to do all kinds +of injection molding some kinds of + + align:start position:0% +of injection molding some kinds of + + + align:start position:0% +of injection molding some kinds of +injection molding lowend end highend + + align:start position:0% +injection molding lowend end highend + + + align:start position:0% +injection molding lowend end highend +middle of the market they focused on the + + align:start position:0% +middle of the market they focused on the + + + align:start position:0% +middle of the market they focused on the +P pet and the thin wall business so they + + align:start position:0% +P pet and the thin wall business so they + + + align:start position:0% +P pet and the thin wall business so they +focused on two segments okay they didn't + + align:start position:0% +focused on two segments okay they didn't + + + align:start position:0% +focused on two segments okay they didn't +do everything and as you say they had + + align:start position:0% +do everything and as you say they had + + + align:start position:0% +do everything and as you say they had +this very interesting culture + + align:start position:0% +this very interesting culture + + + align:start position:0% +this very interesting culture +um so we got that one don't freeze + + align:start position:0% +um so we got that one don't freeze + + + align:start position:0% +um so we got that one don't freeze +again what distinguished those segments + + align:start position:0% +again what distinguished those segments + + + align:start position:0% +again what distinguished those segments +from other + + align:start position:0% +from other + + + align:start position:0% +from other +segments how were the + + align:start position:0% +segments how were the + + + align:start position:0% +segments how were the +pet and the thin wall segment different + + align:start position:0% +pet and the thin wall segment different + + + align:start position:0% +pet and the thin wall segment different +from other parts of the business other + + align:start position:0% +from other parts of the business other + + + align:start position:0% +from other parts of the business other +segments any obvious way yeah they were + + align:start position:0% +segments any obvious way yeah they were + + + align:start position:0% +segments any obvious way yeah they were +trying to sorry I forgot my name t but + + align:start position:0% +trying to sorry I forgot my name t but + + + align:start position:0% +trying to sorry I forgot my name t but +you do remember who you are though we're + + align:start position:0% +you do remember who you are though we're + + + align:start position:0% +you do remember who you are though we're +good there okay yes I think they were + + align:start position:0% +good there okay yes I think they were + + + align:start position:0% +good there okay yes I think they were +trying to find segments where like a + + align:start position:0% +trying to find segments where like a + + + align:start position:0% +trying to find segments where like a +technological advantage is like + + align:start position:0% +technological advantage is like + + + align:start position:0% +technological advantage is like +sustainable actually makes a difference + + align:start position:0% +sustainable actually makes a difference + + + align:start position:0% +sustainable actually makes a difference +like within wall business they it's like + + align:start position:0% +like within wall business they it's like + + + align:start position:0% +like within wall business they it's like +I guess this requires more like + + align:start position:0% +I guess this requires more like + + + align:start position:0% +I guess this requires more like +technological know how to make it and it + + align:start position:0% +technological know how to make it and it + + + align:start position:0% +technological know how to make it and it +allows you to make the walls thinner you + + align:start position:0% +allows you to make the walls thinner you + + + align:start position:0% +allows you to make the walls thinner you +can make it machine go faster and + + align:start position:0% +can make it machine go faster and + + + align:start position:0% +can make it machine go faster and +something stuff like that where it + + align:start position:0% +something stuff like that where it + + + align:start position:0% +something stuff like that where it +hasn't been totally demonetized yet so + + align:start position:0% +hasn't been totally demonetized yet so + + + align:start position:0% +hasn't been totally demonetized yet so +that allows to stay higher what about + + align:start position:0% +that allows to stay higher what about + + + align:start position:0% +that allows to stay higher what about +the pet bottle business what's what's + + align:start position:0% +the pet bottle business what's what's + + + align:start position:0% +the pet bottle business what's what's +how how is that different um it seemed + + align:start position:0% +how how is that different um it seemed + + + align:start position:0% +how how is that different um it seemed +like I wasn't really sure it's some they + + align:start position:0% +like I wasn't really sure it's some they + + + align:start position:0% +like I wasn't really sure it's some they +kind of wind up in that like kind of by + + align:start position:0% +kind of wind up in that like kind of by + + + align:start position:0% +kind of wind up in that like kind of by +accident sort of like well think about I + + align:start position:0% +accident sort of like well think about I + + + align:start position:0% +accident sort of like well think about I +mean there's some nice description of + + align:start position:0% +mean there's some nice description of + + + align:start position:0% +mean there's some nice description of +suppose you're you're doing coke bottles + + align:start position:0% +suppose you're you're doing coke bottles + + + align:start position:0% +suppose you're you're doing coke bottles +and you're running this in incredibly + + align:start position:0% +and you're running this in incredibly + + + align:start position:0% +and you're running this in incredibly +rapid bottling apparatus and you produce + + align:start position:0% +rapid bottling apparatus and you produce + + + align:start position:0% +rapid bottling apparatus and you produce +the bottles and you fill the bottles + + align:start position:0% +the bottles and you fill the bottles + + + align:start position:0% +the bottles and you fill the bottles +under pressure what matters a + + align:start position:0% +under pressure what matters a + + + align:start position:0% +under pressure what matters a +lot quality maybe defects maybe cuz when + + align:start position:0% +lot quality maybe defects maybe cuz when + + + align:start position:0% +lot quality maybe defects maybe cuz when +a when a bottle explodes and you've got + + align:start position:0% +a when a bottle explodes and you've got + + + align:start position:0% +a when a bottle explodes and you've got +to stop the line that's + + align:start position:0% +to stop the line that's + + + align:start position:0% +to stop the line that's +terrible so performance and Technology + + align:start position:0% +terrible so performance and Technology + + + align:start position:0% +terrible so performance and Technology +matter in those segments they're not + + align:start position:0% +matter in those segments they're not + + + align:start position:0% +matter in those segments they're not +making the blow ma only + + align:start position:0% +making the blow ma only + + + align:start position:0% +making the blow ma only +the yeah but you want to make those free + + align:start position:0% +the yeah but you want to make those free + + + align:start position:0% +the yeah but you want to make those free +of defects is when you blow them up when + + align:start position:0% +of defects is when you blow them up when + + + align:start position:0% +of defects is when you blow them up when +you blow them up yeah if you've got + + align:start position:0% +you blow them up yeah if you've got + + + align:start position:0% +you blow them up yeah if you've got +there was there's I think there's a + + align:start position:0% +there was there's I think there's a + + + align:start position:0% +there was there's I think there's a +number in the case about it sort of + + align:start position:0% +number in the case about it sort of + + + align:start position:0% +number in the case about it sort of +typical defects in one of theirs versus + + align:start position:0% +typical defects in one of theirs versus + + + align:start position:0% +typical defects in one of theirs versus +typical defects in competitors and it's + + align:start position:0% +typical defects in competitors and it's + + + align:start position:0% +typical defects in competitors and it's +a big difference and the story is when + + align:start position:0% +a big difference and the story is when + + + align:start position:0% +a big difference and the story is when +you blow them up and then you fill them + + align:start position:0% +you blow them up and then you fill them + + + align:start position:0% +you blow them up and then you fill them +under + + align:start position:0% +under + + + align:start position:0% +under +pressure and they explode and stop a + + align:start position:0% +pressure and they explode and stop a + + + align:start position:0% +pressure and they explode and stop a +bottling line that's terrible so if you + + align:start position:0% +bottling line that's terrible so if you + + + align:start position:0% +bottling line that's terrible so if you +can deliver product that won't do that + + align:start position:0% +can deliver product that won't do that + + + align:start position:0% +can deliver product that won't do that +you've got an advantage okay so it just + + align:start position:0% +you've got an advantage okay so it just + + + align:start position:0% +you've got an advantage okay so it just +it's segments where performance matters + + align:start position:0% +it's segments where performance matters + + + align:start position:0% +it's segments where performance matters +where technology is useful um + + align:start position:0% + + + + align:start position:0% + +one of the things that comes out in the + + align:start position:0% +one of the things that comes out in the + + + align:start position:0% +one of the things that comes out in the +case you have to read it kind of closely + + align:start position:0% +case you have to read it kind of closely + + + align:start position:0% +case you have to read it kind of closely +to get this + + align:start position:0% +to get this + + + align:start position:0% +to get this +but it it buys a lot of stuff it makes + + align:start position:0% +but it it buys a lot of stuff it makes + + + align:start position:0% +but it it buys a lot of stuff it makes +some molds but it buys a lot of + + align:start position:0% +some molds but it buys a lot of + + + align:start position:0% +some molds but it buys a lot of +inputs uh more than its competitors any + + align:start position:0% +inputs uh more than its competitors any + + + align:start position:0% +inputs uh more than its competitors any +obvious + + align:start position:0% + + + + align:start position:0% + +reason Catherine uh well it doesn't the + + align:start position:0% +reason Catherine uh well it doesn't the + + + align:start position:0% +reason Catherine uh well it doesn't the +case that like their campuses are very + + align:start position:0% +case that like their campuses are very + + + align:start position:0% +case that like their campuses are very +centralized and like part goes back to + + align:start position:0% +centralized and like part goes back to + + + align:start position:0% +centralized and like part goes back to +the culture like their employees like + + align:start position:0% +the culture like their employees like + + + align:start position:0% +the culture like their employees like +are generally very happy there and so it + + align:start position:0% +are generally very happy there and so it + + + align:start position:0% +are generally very happy there and so it +say that they buy a lot of their molds + + align:start position:0% +say that they buy a lot of their molds + + + align:start position:0% +say that they buy a lot of their molds +from people who like generally former + + align:start position:0% +from people who like generally former + + + align:start position:0% +from people who like generally former +employees so they buy a lot from former + + align:start position:0% +employees so they buy a lot from former + + + align:start position:0% +employees so they buy a lot from former +employees y so that's part of the + + align:start position:0% +employees y so that's part of the + + + align:start position:0% +employees y so that's part of the +ecosystem as the phrase goes + + align:start position:0% +ecosystem as the phrase goes + + + align:start position:0% +ecosystem as the phrase goes +um but as focused as they are on + + align:start position:0% +um but as focused as they are on + + + align:start position:0% +um but as focused as they are on +technical Excellence of their + + align:start position:0% +technical Excellence of their + + + align:start position:0% +technical Excellence of their +machines could they do that for + + align:start position:0% +machines could they do that for + + + align:start position:0% +machines could they do that for +everything all the + + align:start position:0% +everything all the + + + align:start position:0% +everything all the +puts well they're + + align:start position:0% +puts well they're + + + align:start position:0% +puts well they're +like in instead of trying to just like + + align:start position:0% +like in instead of trying to just like + + + align:start position:0% +like in instead of trying to just like +manufacture like products they they like + + align:start position:0% +manufacture like products they they like + + + align:start position:0% +manufacture like products they they like +have a focus on like service and focus + + align:start position:0% +have a focus on like service and focus + + + align:start position:0% +have a focus on like service and focus +package basically so they they try to + + align:start position:0% +package basically so they they try to + + + align:start position:0% +package basically so they they try to +specialize more because then they can + + align:start position:0% +specialize more because then they can + + + align:start position:0% +specialize more because then they can +provide more services the equipment so + + align:start position:0% +provide more services the equipment so + + + align:start position:0% +provide more services the equipment so +they have technical people out in the + + align:start position:0% +they have technical people out in the + + + align:start position:0% +they have technical people out in the +field so they can provide a great deal + + align:start position:0% +field so they can provide a great deal + + + align:start position:0% +field so they can provide a great deal +of service and sort of co-engineering + + align:start position:0% +of service and sort of co-engineering + + + align:start position:0% +of service and sort of co-engineering +with their with their clients and + + align:start position:0% +with their with their clients and + + + align:start position:0% +with their with their clients and +they're in segments where that + + align:start position:0% +they're in segments where that + + + align:start position:0% +they're in segments where that +matters and trying to do that for all of + + align:start position:0% +matters and trying to do that for all of + + + align:start position:0% +matters and trying to do that for all of +the components and trying to be to hyper + + align:start position:0% +the components and trying to be to hyper + + + align:start position:0% +the components and trying to be to hyper +engineer all of their components would + + align:start position:0% +engineer all of their components would + + + align:start position:0% +engineer all of their components would +spread them a little thin I think and I + + align:start position:0% +spread them a little thin I think and I + + + align:start position:0% +spread them a little thin I think and I +think that's one reason + + align:start position:0% +think that's one reason + + + align:start position:0% +think that's one reason +why um that they they make fewer inputs + + align:start position:0% +why um that they they make fewer inputs + + + align:start position:0% +why um that they they make fewer inputs +than their competitors because they've + + align:start position:0% +than their competitors because they've + + + align:start position:0% +than their competitors because they've +decided to focus on the parts of the + + align:start position:0% +decided to focus on the parts of the + + + align:start position:0% +decided to focus on the parts of the +business where performance and quality + + align:start position:0% +business where performance and quality + + + align:start position:0% +business where performance and quality +and Technology matter um + + align:start position:0% +and Technology matter um + + + align:start position:0% +and Technology matter um +what's the answer to that they + + align:start position:0% +what's the answer to that they + + + align:start position:0% +what's the answer to that they +offer they make some molds particularly + + align:start position:0% +offer they make some molds particularly + + + align:start position:0% +offer they make some molds particularly +for for pet they offer um what hot + + align:start position:0% +for for pet they offer um what hot + + + align:start position:0% +for for pet they offer um what hot +Runners and a variety of other things + + align:start position:0% +Runners and a variety of other things + + + align:start position:0% +Runners and a variety of other things +that competitors don't any reasons + + align:start position:0% +that competitors don't any reasons + + + align:start position:0% +that competitors don't any reasons +why what reading with a hot Runners was + + align:start position:0% +why what reading with a hot Runners was + + + align:start position:0% +why what reading with a hot Runners was +they were selling a hot Runners to + + align:start position:0% +they were selling a hot Runners to + + + align:start position:0% +they were selling a hot Runners to +Gillette or whatever um but Gillette + + align:start position:0% +Gillette or whatever um but Gillette + + + align:start position:0% +Gillette or whatever um but Gillette +wasn't using their um actual mold + + align:start position:0% +wasn't using their um actual mold + + + align:start position:0% +wasn't using their um actual mold +machines but they were using hot Runners + + align:start position:0% +machines but they were using hot Runners + + + align:start position:0% +machines but they were using hot Runners +and then later on they were able to grab + + align:start position:0% +and then later on they were able to grab + + + align:start position:0% +and then later on they were able to grab +cont that you for the actual so it's + + align:start position:0% +cont that you for the actual so it's + + + align:start position:0% +cont that you for the actual so it's +it's part of the system being good at + + align:start position:0% +it's part of the system being good at + + + align:start position:0% +it's part of the system being good at +that adds to Performance and gives you a + + align:start position:0% +that adds to Performance and gives you a + + + align:start position:0% +that adds to Performance and gives you a +business Edge and they're very tightly + + align:start position:0% +business Edge and they're very tightly + + + align:start position:0% +business Edge and they're very tightly +focused on these two segments so you + + align:start position:0% +focused on these two segments so you + + + align:start position:0% +focused on these two segments so you +want to make everything you can for + + align:start position:0% +want to make everything you can for + + + align:start position:0% +want to make everything you can for +those segments you want to not worry + + align:start position:0% +those segments you want to not worry + + + align:start position:0% +those segments you want to not worry +about not worry about the + + align:start position:0% +about not worry about the + + + align:start position:0% +about not worry about the +inputs + + align:start position:0% + + + + align:start position:0% + +so why hasn't and it's made a lot of + + align:start position:0% +so why hasn't and it's made a lot of + + + align:start position:0% +so why hasn't and it's made a lot of +money right the the case makes it clear + + align:start position:0% +money right the the case makes it clear + + + align:start position:0% +money right the the case makes it clear +it's grown like Gang Busters it's got a + + align:start position:0% +it's grown like Gang Busters it's got a + + + align:start position:0% +it's grown like Gang Busters it's got a +return on Equity of something like + + align:start position:0% +return on Equity of something like + + + align:start position:0% +return on Equity of something like +40% why at least until recently hasn't + + align:start position:0% +40% why at least until recently hasn't + + + align:start position:0% +40% why at least until recently hasn't +anybody copied + + align:start position:0% +anybody copied + + + align:start position:0% +anybody copied +them what are the barriers to imitation + + align:start position:0% +them what are the barriers to imitation + + + align:start position:0% +them what are the barriers to imitation +what has made this strategy sustainable + + align:start position:0% +what has made this strategy sustainable + + + align:start position:0% +what has made this strategy sustainable +at least for a while nothing's forever + + align:start position:0% +at least for a while nothing's forever + + + align:start position:0% +at least for a while nothing's forever +Brendan uh they have very you know they + + align:start position:0% +Brendan uh they have very you know they + + + align:start position:0% +Brendan uh they have very you know they +have a huge technological advantage like + + align:start position:0% +have a huge technological advantage like + + + align:start position:0% +have a huge technological advantage like +that machines are a lot more expensive + + align:start position:0% +that machines are a lot more expensive + + + align:start position:0% +that machines are a lot more expensive +there's a deep knowledge Bas there so + + align:start position:0% +there's a deep knowledge Bas there so + + + align:start position:0% +there's a deep knowledge Bas there so +it's like hard to copy the kind of + + align:start position:0% +it's like hard to copy the kind of + + + align:start position:0% +it's like hard to copy the kind of +quality machine that they produce but + + align:start position:0% +quality machine that they produce but + + + align:start position:0% +quality machine that they produce but +you could imagine they don't have nobody + + align:start position:0% +you could imagine they don't have nobody + + + align:start position:0% +you could imagine they don't have nobody +talks about patents though we don't hear + + align:start position:0% +talks about patents though we don't hear + + + align:start position:0% +talks about patents though we don't hear +patent barriers so you could imagine + + align:start position:0% +patent barriers so you could imagine + + + align:start position:0% +patent barriers so you could imagine +they have the only Advanced + + align:start position:0% +they have the only Advanced + + + align:start position:0% +they have the only Advanced +manufacturing center right they've set + + align:start position:0% +manufacturing center right they've set + + + align:start position:0% +manufacturing center right they've set +up a little Think Tank I don't know how + + align:start position:0% +up a little Think Tank I don't know how + + + align:start position:0% +up a little Think Tank I don't know how +little it is they set up a think tank to + + align:start position:0% +little it is they set up a think tank to + + + align:start position:0% +little it is they set up a think tank to +do + + align:start position:0% +do + + + align:start position:0% +do +R&D why don't other people do that they + + align:start position:0% +R&D why don't other people do that they + + + align:start position:0% +R&D why don't other people do that they +don't wantest their money they rather + + align:start position:0% +don't wantest their money they rather + + + align:start position:0% +don't wantest their money they rather +say spend the money elsewhere not have + + align:start position:0% +say spend the money elsewhere not have + + + align:start position:0% +say spend the money elsewhere not have +that cost so they have this is a this is + + align:start position:0% +that cost so they have this is a this is + + + align:start position:0% +that cost so they have this is a this is +part + + align:start position:0% +part + + + align:start position:0% +part +of you could well let me let me push you + + align:start position:0% +of you could well let me let me push you + + + align:start position:0% +of you could well let me let me push you +on that a little bit because they're + + align:start position:0% +on that a little bit because they're + + + align:start position:0% +on that a little bit because they're +making so much much money right they're + + align:start position:0% +making so much much money right they're + + + align:start position:0% +making so much much money right they're +growing gang like Gang Busters they're + + align:start position:0% +growing gang like Gang Busters they're + + + align:start position:0% +growing gang like Gang Busters they're +making so much money wouldn't you + + align:start position:0% +making so much money wouldn't you + + + align:start position:0% +making so much money wouldn't you +imitate them if you could I mean so yeah + + align:start position:0% +imitate them if you could I mean so yeah + + + align:start position:0% +imitate them if you could I mean so yeah +you got to buy a you got to set up a + + align:start position:0% +you got to buy a you got to set up a + + + align:start position:0% +you got to buy a you got to set up a +manufacturing center these are big + + align:start position:0% +manufacturing center these are big + + + align:start position:0% +manufacturing center these are big +companies Manis man is a big company + + align:start position:0% +companies Manis man is a big company + + + align:start position:0% +companies Manis man is a big company +that's why companies eventually did kind + + align:start position:0% +that's why companies eventually did kind + + + align:start position:0% +that's why companies eventually did kind +of get into those the markets that they + + align:start position:0% +of get into those the markets that they + + + align:start position:0% +of get into those the markets that they +s they saw it yeah you they sold cheaper + + align:start position:0% +s they saw it yeah you they sold cheaper + + + align:start position:0% +s they saw it yeah you they sold cheaper +machines that could do the same job + + align:start position:0% +machines that could do the same job + + + align:start position:0% +machines that could do the same job +maybe not the same quality close and try + + align:start position:0% +maybe not the same quality close and try + + + align:start position:0% +maybe not the same quality close and try +to come in on price yeah the kind of + + align:start position:0% +to come in on price yeah the kind of + + + align:start position:0% +to come in on price yeah the kind of +customer though that's like concerned + + align:start position:0% +customer though that's like concerned + + + align:start position:0% +customer though that's like concerned +about quality and is willing to pay more + + align:start position:0% +about quality and is willing to pay more + + + align:start position:0% +about quality and is willing to pay more +for it like it would make more sense it + + align:start position:0% +for it like it would make more sense it + + + align:start position:0% +for it like it would make more sense it +would go with the company that has been + + align:start position:0% +would go with the company that has been + + + align:start position:0% +would go with the company that has been +doing it for longer and kind of has the + + align:start position:0% +doing it for longer and kind of has the + + + align:start position:0% +doing it for longer and kind of has the +history and reputation rather than you + + align:start position:0% +history and reputation rather than you + + + align:start position:0% +history and reputation rather than you +know a company that is just like copy + + align:start position:0% +know a company that is just like copy + + + align:start position:0% +know a company that is just like copy +their technology and is doing that n of + + align:start position:0% +their technology and is doing that n of + + + align:start position:0% +their technology and is doing that n of +the market and doesn't have reputation + + align:start position:0% +the market and doesn't have reputation + + + align:start position:0% +the market and doesn't have reputation +and they've really sort of built the + + align:start position:0% +and they've really sort of built the + + + align:start position:0% +and they've really sort of built the +company to do this haven't they Mario + + align:start position:0% +company to do this haven't they Mario + + + align:start position:0% +company to do this haven't they Mario +well my guess would be um if you if you + + align:start position:0% +well my guess would be um if you if you + + + align:start position:0% +well my guess would be um if you if you +try to imitate you're effectively + + align:start position:0% +try to imitate you're effectively + + + align:start position:0% +try to imitate you're effectively +increaseing competition that you know + + align:start position:0% +increaseing competition that you know + + + align:start position:0% +increaseing competition that you know +does make into bits not as profitable as + + align:start position:0% +does make into bits not as profitable as + + + align:start position:0% +does make into bits not as profitable as +it would be otherwise so the segment may + + align:start position:0% +it would be otherwise so the segment may + + + align:start position:0% +it would be otherwise so the segment may +not be may not be that big you're saying + + align:start position:0% +not be may not be that big you're saying + + + align:start position:0% +not be may not be that big you're saying +and so you'd have to do the numbers to + + align:start position:0% +and so you'd have to do the numbers to + + + align:start position:0% +and so you'd have to do the numbers to +say is there room for two of us to play + + align:start position:0% +say is there room for two of us to play + + + align:start position:0% +say is there room for two of us to play +this game Maxwell also a lot to do with + + align:start position:0% +this game Maxwell also a lot to do with + + + align:start position:0% +this game Maxwell also a lot to do with +the + + align:start position:0% +the + + + align:start position:0% +the +culture that + + align:start position:0% +culture that + + + align:start position:0% +culture that +cure it's hard to swi entire culture + + align:start position:0% +cure it's hard to swi entire culture + + + align:start position:0% +cure it's hard to swi entire culture +yeah the culture is sort of part of it + + align:start position:0% +yeah the culture is sort of part of it + + + align:start position:0% +yeah the culture is sort of part of it +is an intriguing part of it isn't it + + align:start position:0% +is an intriguing part of it isn't it + + + align:start position:0% +is an intriguing part of it isn't it +they've got a peculiar culture and I + + align:start position:0% +they've got a peculiar culture and I + + + align:start position:0% +they've got a peculiar culture and I +want to come back to that Charlotte also + + align:start position:0% +want to come back to that Charlotte also + + + align:start position:0% +want to come back to that Charlotte also +the fact that like we said they were + + align:start position:0% +the fact that like we said they were + + + align:start position:0% +the fact that like we said they were +they're only focusing on this one thing + + align:start position:0% +they're only focusing on this one thing + + + align:start position:0% +they're only focusing on this one thing +whereas other companies that were also + + align:start position:0% +whereas other companies that were also + + + align:start position:0% +whereas other companies that were also +in this mold making business focus more + + align:start position:0% +in this mold making business focus more + + + align:start position:0% +in this mold making business focus more +widely like even when they started to + + align:start position:0% +widely like even when they started to + + + align:start position:0% +widely like even when they started to +come into this area they sort of added + + align:start position:0% +come into this area they sort of added + + + align:start position:0% +come into this area they sort of added +it on to the machines they already had + + align:start position:0% +it on to the machines they already had + + + align:start position:0% +it on to the machines they already had +instead of like actually changing into + + align:start position:0% +instead of like actually changing into + + + align:start position:0% +instead of like actually changing into +the same company as H like nobody like + + align:start position:0% +the same company as H like nobody like + + + align:start position:0% +the same company as H like nobody like +shut down all their other manufacturing + + align:start position:0% +shut down all their other manufacturing + + + align:start position:0% +shut down all their other manufacturing +and focused specifically on these two + + align:start position:0% +and focused specifically on these two + + + align:start position:0% +and focused specifically on these two +things they kind of just like + + align:start position:0% +things they kind of just like + + + align:start position:0% +things they kind of just like +Incorporated it into what they were + + align:start position:0% +Incorporated it into what they were + + + align:start position:0% +Incorporated it into what they were +already doing so maybe companies like + + align:start position:0% +already doing so maybe companies like + + + align:start position:0% +already doing so maybe companies like +whenever they calculated what it would + + align:start position:0% +whenever they calculated what it would + + + align:start position:0% +whenever they calculated what it would +take for them to get to the point where + + align:start position:0% +take for them to get to the point where + + + align:start position:0% +take for them to get to the point where +husky was would just have like change + + align:start position:0% +husky was would just have like change + + + align:start position:0% +husky was would just have like change +their compy so this is It's would sort + + align:start position:0% +their compy so this is It's would sort + + + align:start position:0% +their compy so this is It's would sort +of be a little bit of the reverse of + + align:start position:0% +of be a little bit of the reverse of + + + align:start position:0% +of be a little bit of the reverse of +Continental versus Continental light + + align:start position:0% +Continental versus Continental light + + + align:start position:0% +Continental versus Continental light +this would be like um well they tried it + + align:start position:0% +this would be like um well they tried it + + + align:start position:0% +this would be like um well they tried it +this would be like grafting a luxury car + + align:start position:0% +this would be like grafting a luxury car + + + align:start position:0% +this would be like grafting a luxury car +business onto Volkswagen or as Toyota + + align:start position:0% +business onto Volkswagen or as Toyota + + + align:start position:0% +business onto Volkswagen or as Toyota +did doing Lexus which they set off to + + align:start position:0% +did doing Lexus which they set off to + + + align:start position:0% +did doing Lexus which they set off to +one side because you really couldn't do + + align:start position:0% +one side because you really couldn't do + + + align:start position:0% +one side because you really couldn't do +the mainstream Toyota business and the + + align:start position:0% +the mainstream Toyota business and the + + + align:start position:0% +the mainstream Toyota business and the +Lexus business under the same management + + align:start position:0% +Lexus business under the same management + + + align:start position:0% +Lexus business under the same management +so part of it is they really built it + + align:start position:0% +so part of it is they really built it + + + align:start position:0% +so part of it is they really built it +for this uh do you think it has higher + + align:start position:0% +for this uh do you think it has higher + + + align:start position:0% +for this uh do you think it has higher +or lower than average costs that's + + align:start position:0% +or lower than average costs that's + + + align:start position:0% +or lower than average costs that's +pretty clear I + + align:start position:0% + + + + align:start position:0% + +think Matthew what do you think you + + align:start position:0% +think Matthew what do you think you + + + align:start position:0% +think Matthew what do you think you +think Husky's a high cost operation or a + + align:start position:0% +think Husky's a high cost operation or a + + + align:start position:0% +think Husky's a high cost operation or a +lowcost + + align:start position:0% +lowcost + + + align:start position:0% +lowcost +operation uh well I mean they're they're + + align:start position:0% +operation uh well I mean they're they're + + + align:start position:0% +operation uh well I mean they're they're +high in the sense of like charging no + + align:start position:0% +high in the sense of like charging no + + + align:start position:0% +high in the sense of like charging no +not in terms of high price but in terms + + align:start position:0% +not in terms of high price but in terms + + + align:start position:0% +not in terms of high price but in terms +of their cost + + align:start position:0% +of their cost + + + align:start position:0% +of their cost +oh even though they've got this lab on + + align:start position:0% +oh even though they've got this lab on + + + align:start position:0% +oh even though they've got this lab on +the side they've got this Advanced + + align:start position:0% +the side they've got this Advanced + + + align:start position:0% +the side they've got this Advanced +manufacturing center they've got daycare + + align:start position:0% +manufacturing center they've got daycare + + + align:start position:0% +manufacturing center they've got daycare +they very ecologically + + align:start position:0% +they very ecologically + + + align:start position:0% +they very ecologically +good charging high for is that nobody + + align:start position:0% +good charging high for is that nobody + + + align:start position:0% +good charging high for is that nobody +can + + align:start position:0% +can + + + align:start position:0% +can +produce nice as they are and so like I'm + + align:start position:0% +produce nice as they are and so like I'm + + + align:start position:0% +produce nice as they are and so like I'm +I'm saying low in comparison to what + + align:start position:0% +I'm saying low in comparison to what + + + align:start position:0% +I'm saying low in comparison to what +they're charging that may be but but in + + align:start position:0% +they're charging that may be but but in + + + align:start position:0% +they're charging that may be but but in +comparison to their competitors uh + + align:start position:0% +comparison to their competitors uh + + + align:start position:0% +comparison to their competitors uh +they're higher because they're producing + + align:start position:0% +they're higher because they're producing + + + align:start position:0% +they're higher because they're producing +higher quality they're producing higher + + align:start position:0% +higher quality they're producing higher + + + align:start position:0% +higher quality they're producing higher +quality and if you think about the + + align:start position:0% +quality and if you think about the + + + align:start position:0% +quality and if you think about the +culture and everything else this is not + + align:start position:0% +culture and everything else this is not + + + align:start position:0% +culture and everything else this is not +a company that + + align:start position:0% +a company that + + + align:start position:0% +a company that +skimps this is not a company that skimps + + align:start position:0% +skimps this is not a company that skimps + + + align:start position:0% +skimps this is not a company that skimps +they invest in R&D they invest in + + align:start position:0% +they invest in R&D they invest in + + + align:start position:0% +they invest in R&D they invest in +technology they invest in their people + + align:start position:0% +technology they invest in their people + + + align:start position:0% +technology they invest in their people +um do you think that's important the + + align:start position:0% +um do you think that's important the + + + align:start position:0% +um do you think that's important the +culture is that is that a key part of + + align:start position:0% +culture is that is that a key part of + + + align:start position:0% +culture is that is that a key part of +the story you + + align:start position:0% +the story you + + + align:start position:0% +the story you +think not sure I know the answer to this + + align:start position:0% +think not sure I know the answer to this + + + align:start position:0% +think not sure I know the answer to this +but um just we've mentioned before it's + + align:start position:0% +but um just we've mentioned before it's + + + align:start position:0% +but um just we've mentioned before it's +something you can get up in the morning + + align:start position:0% +something you can get up in the morning + + + align:start position:0% +something you can get up in the morning +go and work for Keeps people motivated + + align:start position:0% +go and work for Keeps people motivated + + + align:start position:0% +go and work for Keeps people motivated +keeps your + + align:start position:0% +keeps your + + + align:start position:0% +keeps your +work even getting your tsquare imagine T + + align:start position:0% +work even getting your tsquare imagine T + + + align:start position:0% +work even getting your tsquare imagine T +squares even getting your tsquare + + align:start position:0% +squares even getting your tsquare + + + align:start position:0% +squares even getting your tsquare +straightened on your desk you think + + align:start position:0% +straightened on your desk you think + + + align:start position:0% +straightened on your desk you think +I mean it's it's it's a it's + + align:start position:0% +I mean it's it's it's a it's + + + align:start position:0% +I mean it's it's it's a it's +an yeah it's an neatening your code when + + align:start position:0% +an yeah it's an neatening your code when + + + align:start position:0% +an yeah it's an neatening your code when +you're gone it's an interesting culture + + align:start position:0% +you're gone it's an interesting culture + + + align:start position:0% +you're gone it's an interesting culture +I have to say Matthew you raising your + + align:start position:0% +I have to say Matthew you raising your + + + align:start position:0% +I have to say Matthew you raising your +hand yeah uh I mean they said in there + + align:start position:0% +hand yeah uh I mean they said in there + + + align:start position:0% +hand yeah uh I mean they said in there +that whenever they extended had like + + align:start position:0% +that whenever they extended had like + + + align:start position:0% +that whenever they extended had like +extended daycare hours it was uh kind of + + align:start position:0% +extended daycare hours it was uh kind of + + + align:start position:0% +extended daycare hours it was uh kind of +a things like make them work harder not + + align:start position:0% +a things like make them work harder not + + + align:start position:0% +a things like make them work harder not +just for extended dayare hours for the + + align:start position:0% +just for extended dayare hours for the + + + align:start position:0% +just for extended dayare hours for the +kids well they're not they're not doing + + align:start position:0% +kids well they're not they're not doing + + + align:start position:0% +kids well they're not they're not doing +charity are they but they have a + + align:start position:0% +charity are they but they have a + + + align:start position:0% +charity are they but they have a +particular culture of we value our + + align:start position:0% +particular culture of we value our + + + align:start position:0% +particular culture of we value our +people we value the environment we value + + align:start position:0% +people we value the environment we value + + + align:start position:0% +people we value the environment we value +Excellence which would be a tough + + align:start position:0% +Excellence which would be a tough + + + align:start position:0% +Excellence which would be a tough +culture to sustain if they were ending + + align:start position:0% +culture to sustain if they were ending + + + align:start position:0% +culture to sustain if they were ending +for the aiming for the low end of the + + align:start position:0% +for the aiming for the low end of the + + + align:start position:0% +for the aiming for the low end of the +market right if you're aiming for the + + align:start position:0% +market right if you're aiming for the + + + align:start position:0% +market right if you're aiming for the +lowend that's tough if you're aiming for + + align:start position:0% +lowend that's tough if you're aiming for + + + align:start position:0% +lowend that's tough if you're aiming for +the + + align:start position:0% +the + + + align:start position:0% +the +highend it's like Ritz Carlton aim + + align:start position:0% +highend it's like Ritz Carlton aim + + + align:start position:0% +highend it's like Ritz Carlton aim +hotels aim for a particular kind of + + align:start position:0% +hotels aim for a particular kind of + + + align:start position:0% +hotels aim for a particular kind of +service and their code is ladies and + + align:start position:0% +service and their code is ladies and + + + align:start position:0% +service and their code is ladies and +gentlemen served by ladies and gentlemen + + align:start position:0% +gentlemen served by ladies and gentlemen + + + align:start position:0% +gentlemen served by ladies and gentlemen +if you're going to treat your people + + align:start position:0% +if you're going to treat your people + + + align:start position:0% +if you're going to treat your people +like ladies and + + align:start position:0% +like ladies and + + + align:start position:0% +like ladies and +gentlemen you're going to have higher + + align:start position:0% +gentlemen you're going to have higher + + + align:start position:0% +gentlemen you're going to have higher +costs than if you treat them like Pon + + align:start position:0% +costs than if you treat them like Pon + + + align:start position:0% +costs than if you treat them like Pon +scum you will also with some luck get + + align:start position:0% +scum you will also with some luck get + + + align:start position:0% +scum you will also with some luck get +better get better service so this is a + + align:start position:0% +better get better service so this is a + + + align:start position:0% +better get better service so this is a +culture that really does aim high would + + align:start position:0% +culture that really does aim high would + + + align:start position:0% +culture that really does aim high would +you like to work + + align:start position:0% + + + + align:start position:0% + +there show of hands who'd like to work + + align:start position:0% +there show of hands who'd like to work + + + align:start position:0% +there show of hands who'd like to work +for this + + align:start position:0% + + + + align:start position:0% + +company okay who would find it really + + align:start position:0% +company okay who would find it really + + + align:start position:0% +company okay who would find it really +awful Charlotte would not like her T + + align:start position:0% +awful Charlotte would not like her T + + + align:start position:0% +awful Charlotte would not like her T +Square straightened NE neither would + + align:start position:0% +Square straightened NE neither would + + + align:start position:0% +Square straightened NE neither would +Maxwell okay I mean it's a it's it's for + + align:start position:0% +Maxwell okay I mean it's a it's it's for + + + align:start position:0% +Maxwell okay I mean it's a it's it's for +some people and not for others right + + align:start position:0% +some people and not for others right + + + align:start position:0% +some people and not for others right +it's it's + + align:start position:0% +it's it's + + + align:start position:0% +it's it's +autocratic the boss runs it one of the + + align:start position:0% +autocratic the boss runs it one of the + + + align:start position:0% +autocratic the boss runs it one of the +questions it's suggested for discussion + + align:start position:0% +questions it's suggested for discussion + + + align:start position:0% +questions it's suggested for discussion +is could you do this company without um + + align:start position:0% +is could you do this company without um + + + align:start position:0% +is could you do this company without um +uh what's his face shap in charge uh + + align:start position:0% +uh what's his face shap in charge uh + + + align:start position:0% +uh what's his face shap in charge uh +could you Shad rather could you do this + + align:start position:0% +could you Shad rather could you do this + + + align:start position:0% +could you Shad rather could you do this +without an autocrat in charge such a + + align:start position:0% +without an autocrat in charge such a + + + align:start position:0% +without an autocrat in charge such a +strong culture such a tight Focus + + align:start position:0% +strong culture such a tight Focus + + + align:start position:0% +strong culture such a tight Focus +not obvious not + + align:start position:0% +not obvious not + + + align:start position:0% +not obvious not +obvious + + align:start position:0% +obvious + + + align:start position:0% +obvious +okay uh what else do I want to do this + + align:start position:0% +okay uh what else do I want to do this + + + align:start position:0% +okay uh what else do I want to do this +is some numbers which I I don't expect + + align:start position:0% +is some numbers which I I don't expect + + + align:start position:0% +is some numbers which I I don't expect +you to have done and I should have made + + align:start position:0% +you to have done and I should have made + + + align:start position:0% +you to have done and I should have made +this clear because you can do a fair + + align:start position:0% +this clear because you can do a fair + + + align:start position:0% +this clear because you can do a fair +amount of work on the numbers but and + + align:start position:0% +amount of work on the numbers but and + + + align:start position:0% +amount of work on the numbers but and +I'll illustrate this kind of analysis + + align:start position:0% +I'll illustrate this kind of analysis + + + align:start position:0% +I'll illustrate this kind of analysis +for products like + + align:start position:0% +for products like + + + align:start position:0% +for products like +this you can it is often + + align:start position:0% +this you can it is often + + + align:start position:0% +this you can it is often +useful and Energy Products a lot of them + + align:start position:0% +useful and Energy Products a lot of them + + + align:start position:0% +useful and Energy Products a lot of them +come into this category like light bulbs + + align:start position:0% +come into this category like light bulbs + + + align:start position:0% +come into this category like light bulbs +you can you can do the demand analysis + + align:start position:0% +you can you can do the demand analysis + + + align:start position:0% +you can you can do the demand analysis +by simply turning yourself around and + + align:start position:0% +by simply turning yourself around and + + + align:start position:0% +by simply turning yourself around and +thinking about this as a + + align:start position:0% +thinking about this as a + + + align:start position:0% +thinking about this as a +buyer if you were a buyer producing + + align:start position:0% +buyer if you were a buyer producing + + + align:start position:0% +buyer if you were a buyer producing +bottles what would you be willing to pay + + align:start position:0% +bottles what would you be willing to pay + + + align:start position:0% +bottles what would you be willing to pay +for a husky system versus some other + + align:start position:0% +for a husky system versus some other + + + align:start position:0% +for a husky system versus some other +system given the parameters and that + + align:start position:0% +system given the parameters and that + + + align:start position:0% +system given the parameters and that +gives you a sense of what husky can + + align:start position:0% +gives you a sense of what husky can + + + align:start position:0% +gives you a sense of what husky can +charge given other people's it's it's a + + align:start position:0% +charge given other people's it's it's a + + + align:start position:0% +charge given other people's it's it's a +um it's easier when it's something like + + align:start position:0% +um it's easier when it's something like + + + align:start position:0% +um it's easier when it's something like +we're making bottles it's a little + + align:start position:0% +we're making bottles it's a little + + + align:start position:0% +we're making bottles it's a little +harder when we're making Priuses is cuz + + align:start position:0% +harder when we're making Priuses is cuz + + + align:start position:0% +harder when we're making Priuses is cuz +you don't know what the willingness to + + align:start position:0% +you don't know what the willingness to + + + align:start position:0% +you don't know what the willingness to +pay for intangibles + + align:start position:0% +pay for intangibles + + + align:start position:0% +pay for intangibles +is or hardwood Interiors in a car that + + align:start position:0% +is or hardwood Interiors in a car that + + + align:start position:0% +is or hardwood Interiors in a car that +you can't sort of read off the process + + align:start position:0% +you can't sort of read off the process + + + align:start position:0% +you can't sort of read off the process +figures but but for something like light + + align:start position:0% +figures but but for something like light + + + align:start position:0% +figures but but for something like light +bulbs for something like injection + + align:start position:0% +bulbs for something like injection + + + align:start position:0% +bulbs for something like injection +molding machines you can say okay I'm + + align:start position:0% +molding machines you can say okay I'm + + + align:start position:0% +molding machines you can say okay I'm +running a factory what would I buy at + + align:start position:0% +running a factory what would I buy at + + + align:start position:0% +running a factory what would I buy at +different prices and turn the analysis + + align:start position:0% +different prices and turn the analysis + + + align:start position:0% +different prices and turn the analysis +around and I'll just show you the + + align:start position:0% +around and I'll just show you the + + + align:start position:0% +around and I'll just show you the +results these aren't my numbers these + + align:start position:0% +results these aren't my numbers these + + + align:start position:0% +results these aren't my numbers these +are somebody else's numbers but it's + + align:start position:0% +are somebody else's numbers but it's + + + align:start position:0% +are somebody else's numbers but it's +it's useful for this kind of analysis + + align:start position:0% +it's useful for this kind of analysis + + + align:start position:0% +it's useful for this kind of analysis +you basically want to say start with + + align:start position:0% +you basically want to say start with + + + align:start position:0% +you basically want to say start with +arriv + + align:start position:0% +arriv + + + align:start position:0% +arriv +Ral what would it cost in terms of the + + align:start position:0% +Ral what would it cost in terms of the + + + align:start position:0% +Ral what would it cost in terms of the +machine maybe the fact that you've got + + align:start position:0% +machine maybe the fact that you've got + + + align:start position:0% +machine maybe the fact that you've got +to get more machines because it's not as + + align:start position:0% +to get more machines because it's not as + + + align:start position:0% +to get more machines because it's not as +productive the fact that maybe it takes + + align:start position:0% +productive the fact that maybe it takes + + + align:start position:0% +productive the fact that maybe it takes +more energy the fact that it takes more + + align:start position:0% +more energy the fact that it takes more + + + align:start position:0% +more energy the fact that it takes more +raw materials what would it cost you + + align:start position:0% +raw materials what would it cost you + + + align:start position:0% +raw materials what would it cost you +this is called P star to do what you get + + align:start position:0% +this is called P star to do what you get + + + align:start position:0% +this is called P star to do what you get +out of a Husky system for price P you + + align:start position:0% +out of a Husky system for price P you + + + align:start position:0% +out of a Husky system for price P you +there's enough in the case you can do + + align:start position:0% +there's enough in the case you can do + + + align:start position:0% +there's enough in the case you can do +this if you're very + + align:start position:0% +this if you're very + + + align:start position:0% +this if you're very +ambitious for thin walls and for pet + + align:start position:0% +ambitious for thin walls and for pet + + + align:start position:0% +ambitious for thin walls and for pet +systems this is the calculation a + + align:start position:0% +systems this is the calculation a + + + align:start position:0% +systems this is the calculation a +calculation for thin + + align:start position:0% +calculation for thin + + + align:start position:0% +calculation for thin +wall the + + align:start position:0% +wall the + + + align:start position:0% +wall the +competitors for Mar used marger and + + align:start position:0% +competitors for Mar used marger and + + + align:start position:0% +competitors for Mar used marger and +containers the competitor's system takes + + align:start position:0% +containers the competitor's system takes + + + align:start position:0% +containers the competitor's system takes +has a longer cycle time it produces uh a + + align:start position:0% +has a longer cycle time it produces uh a + + + align:start position:0% +has a longer cycle time it produces uh a +heavier components a heavier weight + + align:start position:0% +heavier components a heavier weight + + + align:start position:0% +heavier components a heavier weight +container it costs less + + align:start position:0% +container it costs less + + + align:start position:0% +container it costs less +so to get the same + + align:start position:0% +so to get the same + + + align:start position:0% +so to get the same +output again this assumes you have a + + align:start position:0% +output again this assumes you have a + + + align:start position:0% +output again this assumes you have a +large Factory you'd need one and 2/3 + + align:start position:0% +large Factory you'd need one and 2/3 + + + align:start position:0% +large Factory you'd need one and 2/3 +competitor machines uh for uh to get as + + align:start position:0% +competitor machines uh for uh to get as + + + align:start position:0% +competitor machines uh for uh to get as +much as out of a Husky + + align:start position:0% +much as out of a Husky + + + align:start position:0% +much as out of a Husky +machine that means one and 2/3 time 350 + + align:start position:0% +machine that means one and 2/3 time 350 + + + align:start position:0% +machine that means one and 2/3 time 350 +is + + align:start position:0% +is + + + align:start position:0% +is +408 there's also a resin saving because + + align:start position:0% +408 there's also a resin saving because + + + align:start position:0% +408 there's also a resin saving because +the + + align:start position:0% +the + + + align:start position:0% +the +Husky container is + + align:start position:0% +Husky container is + + + align:start position:0% +Husky container is +lighter so to replace a $400,000 husky + + align:start position:0% +lighter so to replace a $400,000 husky + + + align:start position:0% +lighter so to replace a $400,000 husky +machine + + align:start position:0% +machine + + + align:start position:0% +machine +machine you'd have to do uh + + align:start position:0% +machine you'd have to do uh + + + align:start position:0% +machine you'd have to do uh +$448,000 versus worth of competitor + + align:start position:0% +$448,000 versus worth of competitor + + + align:start position:0% +$448,000 versus worth of competitor +Equipment Plus extra resin per year all + + align:start position:0% +Equipment Plus extra resin per year all + + + align:start position:0% +Equipment Plus extra resin per year all +right that's a willingness to pay + + align:start position:0% +right that's a willingness to pay + + + align:start position:0% +right that's a willingness to pay +analysis so that says husky could + + align:start position:0% +analysis so that says husky could + + + align:start position:0% +analysis so that says husky could +depending on how the competitor + + align:start position:0% +depending on how the competitor + + + align:start position:0% +depending on how the competitor +discounted and depending on how much the + + align:start position:0% +discounted and depending on how much the + + + align:start position:0% +discounted and depending on how much the +competitor produced husky could charge + + align:start position:0% +competitor produced husky could charge + + + align:start position:0% +competitor produced husky could charge +even more than + + align:start position:0% +even more than + + + align:start position:0% +even more than +$400,000 and would still be the machine + + align:start position:0% +$400,000 and would still be the machine + + + align:start position:0% +$400,000 and would still be the machine +of + + align:start position:0% +of + + + align:start position:0% +of +choice right this is the kind of + + align:start position:0% +choice right this is the kind of + + + align:start position:0% +choice right this is the kind of +analysis you would expect a buyer to do + + align:start position:0% +analysis you would expect a buyer to do + + + align:start position:0% +analysis you would expect a buyer to do +deciding what kind of machine to buy and + + align:start position:0% +deciding what kind of machine to buy and + + + align:start position:0% +deciding what kind of machine to buy and +it's the kind of analysis you'd expect + + align:start position:0% +it's the kind of analysis you'd expect + + + align:start position:0% +it's the kind of analysis you'd expect +husky to do in thinking about + + align:start position:0% + + + + align:start position:0% + +price in the past I've taught a a + + align:start position:0% +price in the past I've taught a a + + + align:start position:0% +price in the past I've taught a a +pricing course here at Sloan and my my + + align:start position:0% +pricing course here at Sloan and my my + + + align:start position:0% +pricing course here at Sloan and my my +favorite my favorite case is a case + + align:start position:0% +favorite my favorite case is a case + + + align:start position:0% +favorite my favorite case is a case +about contact lenses for + + align:start position:0% +about contact lenses for + + + align:start position:0% +about contact lenses for +chickens and it's a great it's a great + + align:start position:0% +chickens and it's a great it's a great + + + align:start position:0% +chickens and it's a great it's a great +pricing case because the contact lenses + + align:start position:0% +pricing case because the contact lenses + + + align:start position:0% +pricing case because the contact lenses +for chickens cost + + align:start position:0% +for chickens cost + + + align:start position:0% +for chickens cost +nothing you you put them in the chicken + + align:start position:0% +nothing you you put them in the chicken + + + align:start position:0% +nothing you you put them in the chicken +for about 25 cents a chicken they cost + + align:start position:0% +for about 25 cents a chicken they cost + + + align:start position:0% +for about 25 cents a chicken they cost +about a penny and they keep the chickens + + align:start position:0% +about a penny and they keep the chickens + + + align:start position:0% +about a penny and they keep the chickens +if they work from pecking each other to + + align:start position:0% +if they work from pecking each other to + + + align:start position:0% +if they work from pecking each other to +death and if you do the calculation you + + align:start position:0% +death and if you do the calculation you + + + align:start position:0% +death and if you do the calculation you +find those lenses are worth about four + + align:start position:0% +find those lenses are worth about four + + + align:start position:0% +find those lenses are worth about four +bucks a piece madeup number but very + + align:start position:0% +bucks a piece madeup number but very + + + align:start position:0% +bucks a piece madeup number but very +very + + align:start position:0% +very + + + align:start position:0% +very +high and most people in the class + + align:start position:0% +high and most people in the class + + + align:start position:0% +high and most people in the class +immediately say well you know it cost 25 + + align:start position:0% +immediately say well you know it cost 25 + + + align:start position:0% +immediately say well you know it cost 25 +cents so what we'll do is we'll mark it + + align:start position:0% +cents so what we'll do is we'll mark it + + + align:start position:0% +cents so what we'll do is we'll mark it +up to 30 + + align:start position:0% +up to 30 + + + align:start position:0% +up to 30 +and the answer is no if you do the + + align:start position:0% +and the answer is no if you do the + + + align:start position:0% +and the answer is no if you do the +willingness to pay answer you can mark + + align:start position:0% +willingness to pay answer you can mark + + + align:start position:0% +willingness to pay answer you can mark +it up to three + + align:start position:0% +it up to three + + + align:start position:0% +it up to three +bucks as long as you've got the patent + + align:start position:0% +bucks as long as you've got the patent + + + align:start position:0% +bucks as long as you've got the patent +Monopoly on it the buyer would be + + align:start position:0% +Monopoly on it the buyer would be + + + align:start position:0% +Monopoly on it the buyer would be +willing to pay three bucks rather than + + align:start position:0% +willing to pay three bucks rather than + + + align:start position:0% +willing to pay three bucks rather than +do without it in fact if you if it's + + align:start position:0% +do without it in fact if you if it's + + + align:start position:0% +do without it in fact if you if it's +worth $4 on this kind of analysis you + + align:start position:0% +worth $4 on this kind of analysis you + + + align:start position:0% +worth $4 on this kind of analysis you +charge $3 and they're + + align:start position:0% +charge $3 and they're + + + align:start position:0% +charge $3 and they're +happy uh so this is a kind of analysis + + align:start position:0% +happy uh so this is a kind of analysis + + + align:start position:0% +happy uh so this is a kind of analysis +you can do for Industrial + + align:start position:0% +you can do for Industrial + + + align:start position:0% +you can do for Industrial +Products that's a great case except as + + align:start position:0% +Products that's a great case except as + + + align:start position:0% +Products that's a great case except as +it turns out the contact lenses fell out + + align:start position:0% +it turns out the contact lenses fell out + + + align:start position:0% +it turns out the contact lenses fell out +of the chickens the chickens plucked + + align:start position:0% +of the chickens the chickens plucked + + + align:start position:0% +of the chickens the chickens plucked +each other to death and the firm went + + align:start position:0% +each other to death and the firm went + + + align:start position:0% +each other to death and the firm went +broke but + + align:start position:0% +broke but + + + align:start position:0% +broke but +still still it's a great case to teach + + align:start position:0% +still still it's a great case to teach + + + align:start position:0% +still still it's a great case to teach +uh it it it it fails only the realistic + + align:start position:0% +uh it it it it fails only the realistic + + + align:start position:0% +uh it it it it fails only the realistic +test this says the more containers the + + align:start position:0% +test this says the more containers the + + + align:start position:0% +test this says the more containers the +uh somebody wants to produce and the + + align:start position:0% +uh somebody wants to produce and the + + + align:start position:0% +uh somebody wants to produce and the +lower their discount rate uh the better + + align:start position:0% +lower their discount rate uh the better + + + align:start position:0% +lower their discount rate uh the better +the Husky system is this is a similar + + align:start position:0% +the Husky system is this is a similar + + + align:start position:0% +the Husky system is this is a similar +analysis of willingness to pay analysis + + align:start position:0% +analysis of willingness to pay analysis + + + align:start position:0% +analysis of willingness to pay analysis +for a pet preform system and + + align:start position:0% +for a pet preform system and + + + align:start position:0% +for a pet preform system and +again the + + align:start position:0% +again the + + + align:start position:0% +again the +husky husky container weight is lower um + + align:start position:0% +husky husky container weight is lower um + + + align:start position:0% +husky husky container weight is lower um +the cost + + align:start position:0% + + + + align:start position:0% + +is lower takes up well I'm going to have + + align:start position:0% +is lower takes up well I'm going to have + + + align:start position:0% +is lower takes up well I'm going to have +to go back the the key things you see + + align:start position:0% +to go back the the key things you see + + + align:start position:0% +to go back the the key things you see +will turn out to be the Energy + + align:start position:0% +will turn out to be the Energy + + + align:start position:0% +will turn out to be the Energy +savings and the resin + + align:start position:0% +savings and the resin + + + align:start position:0% +savings and the resin +savings so what you get here is it + + align:start position:0% +savings so what you get here is it + + + align:start position:0% +savings so what you get here is it +produces a lighter container so there's + + align:start position:0% +produces a lighter container so there's + + + align:start position:0% +produces a lighter container so there's +a residence saving it's more efficient + + align:start position:0% +a residence saving it's more efficient + + + align:start position:0% +a residence saving it's more efficient +so there's an energy saving there's also + + align:start position:0% +so there's an energy saving there's also + + + align:start position:0% +so there's an energy saving there's also +a little floor space saving so it's the + + align:start position:0% +a little floor space saving so it's the + + + align:start position:0% +a little floor space saving so it's the +same thing to replace a husky system + + align:start position:0% +same thing to replace a husky system + + + align:start position:0% +same thing to replace a husky system +costing a million + + align:start position:0% +costing a million + + + align:start position:0% +costing a million +to you'd need to spend more + + align:start position:0% +to you'd need to spend more + + + align:start position:0% +to you'd need to spend more +capacity and more yearly cost so again + + align:start position:0% +capacity and more yearly cost so again + + + align:start position:0% +capacity and more yearly cost so again +when you think + + align:start position:0% +when you think + + + align:start position:0% +when you think +about an industrial + + align:start position:0% +about an industrial + + + align:start position:0% +about an industrial +product this is the sort of analysis you + + align:start position:0% +product this is the sort of analysis you + + + align:start position:0% +product this is the sort of analysis you +go + + align:start position:0% +go + + + align:start position:0% +go +through when you're a buyer you do it + + align:start position:0% +through when you're a buyer you do it + + + align:start position:0% +through when you're a buyer you do it +and when you're seller you do it now + + align:start position:0% +and when you're seller you do it now + + + align:start position:0% +and when you're seller you do it now +again the analysis may be different for + + align:start position:0% +again the analysis may be different for + + + align:start position:0% +again the analysis may be different for +different customers this is a case where + + align:start position:0% +different customers this is a case where + + + align:start position:0% +different customers this is a case where +you're assuming that + + align:start position:0% +you're assuming that + + + align:start position:0% +you're assuming that +again uh I + + align:start position:0% +again uh I + + + align:start position:0% +again uh I +can where have I got it yeah I need 1.34 + + align:start position:0% +can where have I got it yeah I need 1.34 + + + align:start position:0% +can where have I got it yeah I need 1.34 +rival systems to to uh replace a husky + + align:start position:0% +rival systems to to uh replace a husky + + + align:start position:0% +rival systems to to uh replace a husky +system because the Husky system is more + + align:start position:0% +system because the Husky system is more + + + align:start position:0% +system because the Husky system is more +productive well depending on how big the + + align:start position:0% +productive well depending on how big the + + + align:start position:0% +productive well depending on how big the +factory is that may or may not make any + + align:start position:0% +factory is that may or may not make any + + + align:start position:0% +factory is that may or may not make any +sense because they don't come in + + align:start position:0% +sense because they don't come in + + + align:start position:0% +sense because they don't come in +fractions if it's a large thing yeah if + + align:start position:0% +fractions if it's a large thing yeah if + + + align:start position:0% +fractions if it's a large thing yeah if +a typical customer has one + + align:start position:0% +a typical customer has one + + + align:start position:0% +a typical customer has one +system then the analysis is going to be + + align:start position:0% +system then the analysis is going to be + + + align:start position:0% +system then the analysis is going to be +different okay any questions about this + + align:start position:0% +different okay any questions about this + + + align:start position:0% +different okay any questions about this +kind of analysis this sort of you know + + align:start position:0% +kind of analysis this sort of you know + + + align:start position:0% +kind of analysis this sort of you know +folks with an engineering background + + align:start position:0% +folks with an engineering background + + + align:start position:0% +folks with an engineering background +this sort of ought to come pretty + + align:start position:0% +this sort of ought to come pretty + + + align:start position:0% +this sort of ought to come pretty +naturally just working out on a + + align:start position:0% +naturally just working out on a + + + align:start position:0% +naturally just working out on a +spreadsheet how would you what would you + + align:start position:0% +spreadsheet how would you what would you + + + align:start position:0% +spreadsheet how would you what would you +do if you didn't buy + + align:start position:0% +do if you didn't buy + + + align:start position:0% +do if you didn't buy +ours uh how would you do it what would + + align:start position:0% +ours uh how would you do it what would + + + align:start position:0% +ours uh how would you do it what would +it cost if is there a Gap is there a Gap + + align:start position:0% +it cost if is there a Gap is there a Gap + + + align:start position:0% +it cost if is there a Gap is there a Gap +so the answer to this is at least as of + + align:start position:0% +so the answer to this is at least as of + + + align:start position:0% +so the answer to this is at least as of +1995 before troubles begin husky + + align:start position:0% +1995 before troubles begin husky + + + align:start position:0% +1995 before troubles begin husky +systems are worth I mean we're charging + + align:start position:0% +systems are worth I mean we're charging + + + align:start position:0% +systems are worth I mean we're charging +a million to for the system but to + + align:start position:0% +a million to for the system but to + + + align:start position:0% +a million to for the system but to +replace it you'd have to spend a + + align:start position:0% +replace it you'd have to spend a + + + align:start position:0% +replace it you'd have to spend a +million3 plus 500,000 a year so in one + + align:start position:0% +million3 plus 500,000 a year so in one + + + align:start position:0% +million3 plus 500,000 a year so in one +sense we are leaving a little money on + + align:start position:0% +sense we are leaving a little money on + + + align:start position:0% +sense we are leaving a little money on +the table in another sense you have to + + align:start position:0% +the table in another sense you have to + + + align:start position:0% +the table in another sense you have to +leave a little money on the table + + align:start position:0% +leave a little money on the table + + + align:start position:0% +leave a little money on the table +because these are approximate + + align:start position:0% +because these are approximate + + + align:start position:0% +because these are approximate +calculations but the answer is Husky + + align:start position:0% +calculations but the answer is Husky + + + align:start position:0% +calculations but the answer is Husky +premiums husky systems Justified their + + align:start position:0% +premiums husky systems Justified their + + + align:start position:0% +premiums husky systems Justified their +premium price going into + + align:start position:0% +premium price going into + + + align:start position:0% +premium price going into +1995 the electricity savings were not an + + align:start position:0% +1995 the electricity savings were not an + + + align:start position:0% +1995 the electricity savings were not an +a trivial part of the reason at least + + align:start position:0% +a trivial part of the reason at least + + + align:start position:0% +a trivial part of the reason at least +for pet preform is this reasonably + + align:start position:0% +for pet preform is this reasonably + + + align:start position:0% +for pet preform is this reasonably +straightforward how you would think + + align:start position:0% +straightforward how you would think + + + align:start position:0% +straightforward how you would think +about doing it just engineer it one way + + align:start position:0% +about doing it just engineer it one way + + + align:start position:0% +about doing it just engineer it one way +engineer it the other way and and check + + align:start position:0% +engineer it the other way and and check + + + align:start position:0% +engineer it the other way and and check +the + + align:start position:0% +the + + + align:start position:0% +the +costs uh all the costs + + align:start position:0% + + + + align:start position:0% + +okay we're now in + + align:start position:0% +okay we're now in + + + align:start position:0% +okay we're now in +1995 what's gone + + align:start position:0% + + + + align:start position:0% + +wrong it's a summer of 95 they had a + + align:start position:0% +wrong it's a summer of 95 they had a + + + align:start position:0% +wrong it's a summer of 95 they had a +great year they're depressed yes res + + align:start position:0% +great year they're depressed yes res + + + align:start position:0% +great year they're depressed yes res +costs are increasing okay resin costs + + align:start position:0% +costs are increasing okay resin costs + + + align:start position:0% +costs are increasing okay resin costs +are increasing that's leading to a + + align:start position:0% +are increasing that's leading to a + + + align:start position:0% +are increasing that's leading to a +decrease in + + align:start position:0% +decrease in + + + align:start position:0% +decrease in +demand is that likely to be a temporary + + align:start position:0% +demand is that likely to be a temporary + + + align:start position:0% +demand is that likely to be a temporary +or a permanent situation do you think + + align:start position:0% +or a permanent situation do you think + + + align:start position:0% +or a permanent situation do you think +temporary yeah it's going to be disequil + + align:start position:0% +temporary yeah it's going to be disequil + + + align:start position:0% +temporary yeah it's going to be disequil +we've seen it before it's a commodity + + align:start position:0% +we've seen it before it's a commodity + + + align:start position:0% +we've seen it before it's a commodity +chemical they just have a capacity + + align:start position:0% +chemical they just have a capacity + + + align:start position:0% +chemical they just have a capacity +shortage so we wouldn't get too Twitchy + + align:start position:0% +shortage so we wouldn't get too Twitchy + + + align:start position:0% +shortage so we wouldn't get too Twitchy +about that anything else Matthew a lot + + align:start position:0% +about that anything else Matthew a lot + + + align:start position:0% +about that anything else Matthew a lot +of competing companies have noticed + + align:start position:0% +of competing companies have noticed + + + align:start position:0% +of competing companies have noticed +their success starting step try to take + + align:start position:0% +their success starting step try to take + + + align:start position:0% +their success starting step try to take +some now we got a problem that's more + + align:start position:0% +some now we got a problem that's more + + + align:start position:0% +some now we got a problem that's more +serious that's more + + align:start position:0% +serious that's more + + + align:start position:0% +serious that's more +serious so um and you know these guys + + align:start position:0% +serious so um and you know these guys + + + align:start position:0% +serious so um and you know these guys +have been through resin shortages and + + align:start position:0% +have been through resin shortages and + + + align:start position:0% +have been through resin shortages and +they don't have a lot of debt and + + align:start position:0% +they don't have a lot of debt and + + + align:start position:0% +they don't have a lot of debt and +they'll probably get through this one + + align:start position:0% +they'll probably get through this one + + + align:start position:0% +they'll probably get through this one +in fact I think it fixed itself within a + + align:start position:0% +in fact I think it fixed itself within a + + + align:start position:0% +in fact I think it fixed itself within a +a year maybe two but the lower cost + + align:start position:0% +a year maybe two but the lower cost + + + align:start position:0% +a year maybe two but the lower cost +competitors going after your Prime + + align:start position:0% +competitors going after your Prime + + + align:start position:0% +competitors going after your Prime +customers with lower + + align:start position:0% +customers with lower + + + align:start position:0% +customers with lower +costs that's + + align:start position:0% +costs that's + + + align:start position:0% +costs that's +Troublesome + + align:start position:0% +Troublesome + + + align:start position:0% +Troublesome +so let's look at this two ways let's + + align:start position:0% +so let's look at this two ways let's + + + align:start position:0% +so let's look at this two ways let's +look at it from the point of view first + + align:start position:0% +look at it from the point of view first + + + align:start position:0% +look at it from the point of view first +of a + + align:start position:0% +of a + + + align:start position:0% +of a +competitor suppose you're one of those + + align:start position:0% +competitor suppose you're one of those + + + align:start position:0% +competitor suppose you're one of those +lowcost + + align:start position:0% +lowcost + + + align:start position:0% +lowcost +competitors you know Husky's going to do + + align:start position:0% +competitors you know Husky's going to do + + + align:start position:0% +competitors you know Husky's going to do +something what do you think Husky's + + align:start position:0% +something what do you think Husky's + + + align:start position:0% +something what do you think Husky's +going to do + + align:start position:0% +going to do + + + align:start position:0% +going to do +one question is what will they do and + + align:start position:0% +one question is what will they do and + + + align:start position:0% +one question is what will they do and +what would you think they would do as a + + align:start position:0% +what would you think they would do as a + + + align:start position:0% +what would you think they would do as a +as a competitor and the other is what + + align:start position:0% +as a competitor and the other is what + + + align:start position:0% +as a competitor and the other is what +would you recommend they do those may be + + align:start position:0% +would you recommend they do those may be + + + align:start position:0% +would you recommend they do those may be +the same if they're as smart as you are + + align:start position:0% +the same if they're as smart as you are + + + align:start position:0% +the same if they're as smart as you are +but they may not be they may not be any + + align:start position:0% +but they may not be they may not be any + + + align:start position:0% +but they may not be they may not be any +thoughts about you're a competitor what + + align:start position:0% +thoughts about you're a competitor what + + + align:start position:0% +thoughts about you're a competitor what +do you think husky + + align:start position:0% +do you think husky + + + align:start position:0% +do you think husky +does Sam their customers and stress like + + align:start position:0% +does Sam their customers and stress like + + + align:start position:0% +does Sam their customers and stress like +the quality of their product like these + + align:start position:0% +the quality of their product like these + + + align:start position:0% +the quality of their product like these +guys are new and they're doing low cost + + align:start position:0% +guys are new and they're doing low cost + + + align:start position:0% +guys are new and they're doing low cost +but the only way they do that is they're + + align:start position:0% +but the only way they do that is they're + + + align:start position:0% +but the only way they do that is they're +cut and corn is like our product for but + + align:start position:0% +cut and corn is like our product for but + + + align:start position:0% +cut and corn is like our product for but +you've worked with us for years you know + + align:start position:0% +you've worked with us for years you know + + + align:start position:0% +you've worked with us for years you know +it's trustworthy and just kind of so you + + align:start position:0% +it's trustworthy and just kind of so you + + + align:start position:0% +it's trustworthy and just kind of so you +think so you think what they would do + + align:start position:0% +think so you think what they would do + + + align:start position:0% +think so you think what they would do +would be to because they've always been + + align:start position:0% +would be to because they've always been + + + align:start position:0% +would be to because they've always been +about technology and technological + + align:start position:0% +about technology and technological + + + align:start position:0% +about technology and technological +leadership and quality they're just + + align:start position:0% +leadership and quality they're just + + + align:start position:0% +leadership and quality they're just +going to double down on that they're + + align:start position:0% +going to double down on that they're + + + align:start position:0% +going to double down on that they're +going to do more communication they're + + align:start position:0% +going to do more communication they're + + + align:start position:0% +going to do more communication they're +going to do more + + align:start position:0% +going to do more + + + align:start position:0% +going to do more +Innovation they're going to ride the + + align:start position:0% +Innovation they're going to ride the + + + align:start position:0% +Innovation they're going to ride the +same horse that's more what I think they + + align:start position:0% +same horse that's more what I think they + + + align:start position:0% +same horse that's more what I think they +should do what do you think they will + + align:start position:0% +should do what do you think they will + + + align:start position:0% +should do what do you think they will +do probably I feel like the first thing + + align:start position:0% +do probably I feel like the first thing + + + align:start position:0% +do probably I feel like the first thing +they might try and do lower their costs + + align:start position:0% +they might try and do lower their costs + + + align:start position:0% +they might try and do lower their costs +drop their prices a little bit I I + + align:start position:0% +drop their prices a little bit I I + + + align:start position:0% +drop their prices a little bit I I +that's they would why do you think they + + align:start position:0% +that's they would why do you think they + + + align:start position:0% +that's they would why do you think they +will do + + align:start position:0% +will do + + + align:start position:0% +will do +it you had me sold you had me sold that + + align:start position:0% +it you had me sold you had me sold that + + + align:start position:0% +it you had me sold you had me sold that +that given their whole culture and given + + align:start position:0% +that given their whole culture and given + + + align:start position:0% +that given their whole culture and given +the way the company's been built that + + align:start position:0% +the way the company's been built that + + + align:start position:0% +the way the company's been built that +they would double down on + + align:start position:0% + + + + align:start position:0% + +Innovation I it's easier to lower it's + + align:start position:0% +Innovation I it's easier to lower it's + + + align:start position:0% +Innovation I it's easier to lower it's +easier to lower easier to lower price in + + align:start position:0% +easier to lower easier to lower price in + + + align:start position:0% +easier to lower easier to lower price in +response I Philip what do you think they + + align:start position:0% +response I Philip what do you think they + + + align:start position:0% +response I Philip what do you think they +will do yeah probably lower the price um + + align:start position:0% +will do yeah probably lower the price um + + + align:start position:0% +will do yeah probably lower the price um +because uh part uh willingness to pay of + + align:start position:0% +because uh part uh willingness to pay of + + + align:start position:0% +because uh part uh willingness to pay of +the buyers is probably going to decrease + + align:start position:0% +the buyers is probably going to decrease + + + align:start position:0% +the buyers is probably going to decrease +because these low competitors because + + align:start position:0% +because these low competitors because + + + align:start position:0% +because these low competitors because +what because the low cost competitors + + align:start position:0% +what because the low cost competitors + + + align:start position:0% +what because the low cost competitors +are rising so the cost of replacing + + align:start position:0% +are rising so the cost of replacing + + + align:start position:0% +are rising so the cost of replacing +their um product is less so they + + align:start position:0% +their um product is less so they + + + align:start position:0% +their um product is less so they +should so you so you think if you you're + + align:start position:0% +should so you so you think if you you're + + + align:start position:0% +should so you so you think if you you're +a competitor the first thing you expect + + align:start position:0% +a competitor the first thing you expect + + + align:start position:0% +a competitor the first thing you expect +them to do is is a price + + align:start position:0% +them to do is is a price + + + align:start position:0% +them to do is is a price +cut okay okay anybody else have any + + align:start position:0% +cut okay okay anybody else have any + + + align:start position:0% +cut okay okay anybody else have any +expect because that's the natural + + align:start position:0% +expect because that's the natural + + + align:start position:0% +expect because that's the natural +response to a lowcost entrant is to come + + align:start position:0% +response to a lowcost entrant is to come + + + align:start position:0% +response to a lowcost entrant is to come +down a bit anybody + + align:start position:0% +down a bit anybody + + + align:start position:0% +down a bit anybody +else David I would not expect them to + + align:start position:0% +else David I would not expect them to + + + align:start position:0% +else David I would not expect them to +cut their prices just because that kills + + align:start position:0% +cut their prices just because that kills + + + align:start position:0% +cut their prices just because that kills +them that's like slip very slow thing + + align:start position:0% +them that's like slip very slow thing + + + align:start position:0% +them that's like slip very slow thing +where then their customers will not be + + align:start position:0% +where then their customers will not be + + + align:start position:0% +where then their customers will not be +willing to pay the higher prices and + + align:start position:0% +willing to pay the higher prices and + + + align:start position:0% +willing to pay the higher prices and +they can't afford to sustain their + + align:start position:0% +they can't afford to sustain their + + + align:start position:0% +they can't afford to sustain their +competitive Advantage you know well are + + align:start position:0% +competitive Advantage you know well are + + + align:start position:0% +competitive Advantage you know well are +you saying what they should do or what + + align:start position:0% +you saying what they should do or what + + + align:start position:0% +you saying what they should do or what +they will do as as someone as a + + align:start position:0% +they will do as as someone as a + + + align:start position:0% +they will do as as someone as a +competitor especially if I'm part of a + + align:start position:0% +competitor especially if I'm part of a + + + align:start position:0% +competitor especially if I'm part of a +larger corporation like the Man Group uh + + align:start position:0% +larger corporation like the Man Group uh + + + align:start position:0% +larger corporation like the Man Group uh +I would not expect them to come down to + + align:start position:0% +I would not expect them to come down to + + + align:start position:0% +I would not expect them to come down to +my price rather they try to stay high + + align:start position:0% +my price rather they try to stay high + + + align:start position:0% +my price rather they try to stay high +and maybe I diversify a little into like + + align:start position:0% +and maybe I diversify a little into like + + + align:start position:0% +and maybe I diversify a little into like +so you you you think they would that + + align:start position:0% +so you you you think they would that + + + align:start position:0% +so you you you think they would that +that Chad would say I can't play a price + + align:start position:0% +that Chad would say I can't play a price + + + align:start position:0% +that Chad would say I can't play a price +game with these + + align:start position:0% +game with these + + + align:start position:0% +game with these +guys I'm going to I'm going to play my + + align:start position:0% +guys I'm going to I'm going to play my + + + align:start position:0% +guys I'm going to I'm going to play my +long suit I'm going to stick with + + align:start position:0% +long suit I'm going to stick with + + + align:start position:0% +long suit I'm going to stick with +technology and high price and + + align:start position:0% +technology and high price and + + + align:start position:0% +technology and high price and +communication and all of those good + + align:start position:0% +communication and all of those good + + + align:start position:0% +communication and all of those good +things okay let's we we're going to get + + align:start position:0% +things okay let's we we're going to get + + + align:start position:0% +things okay let's we we're going to get +the + + align:start position:0% +the + + + align:start position:0% +the +the at least the analysis in the + + align:start position:0% +the at least the analysis in the + + + align:start position:0% +the at least the analysis in the +teaching note on this case says given + + align:start position:0% +teaching note on this case says given + + + align:start position:0% +teaching note on this case says given +what Shad did to get through the 70s you + + align:start position:0% +what Shad did to get through the 70s you + + + align:start position:0% +what Shad did to get through the 70s you +might expect him to double down on + + align:start position:0% +might expect him to double down on + + + align:start position:0% +might expect him to double down on +technology to keep innovating but what + + align:start position:0% +technology to keep innovating but what + + + align:start position:0% +technology to keep innovating but what +should he do I mean there are a whole + + align:start position:0% +should he do I mean there are a whole + + + align:start position:0% +should he do I mean there are a whole +set of things he could + + align:start position:0% +set of things he could + + + align:start position:0% +set of things he could +do right he could cut prices he could + + align:start position:0% +do right he could cut prices he could + + + align:start position:0% +do right he could cut prices he could +cut them generally he could cut them + + align:start position:0% +cut them generally he could cut them + + + align:start position:0% +cut them generally he could cut them +selectively he could cut them in + + align:start position:0% +selectively he could cut them in + + + align:start position:0% +selectively he could cut them in +different markets he could cut them in + + align:start position:0% +different markets he could cut them in + + + align:start position:0% +different markets he could cut them in +different segments he could enter their + + align:start position:0% +different segments he could enter their + + + align:start position:0% +different segments he could enter their +segments Husky's a little small in terms + + align:start position:0% +segments Husky's a little small in terms + + + align:start position:0% +segments Husky's a little small in terms +of production capacity they might try to + + align:start position:0% +of production capacity they might try to + + + align:start position:0% +of production capacity they might try to +get scale by + + align:start position:0% +get scale by + + + align:start position:0% +get scale by +counterattacking they could cut + + align:start position:0% +counterattacking they could cut + + + align:start position:0% +counterattacking they could cut +costs given they're facing low price + + align:start position:0% +costs given they're facing low price + + + align:start position:0% +costs given they're facing low price +competition but they've got this + + align:start position:0% +competition but they've got this + + + align:start position:0% +competition but they've got this +culture that's not a cost focused + + align:start position:0% +culture that's not a cost focused + + + align:start position:0% +culture that's not a cost focused +culture it's a quality focused people + + align:start position:0% +culture it's a quality focused people + + + align:start position:0% +culture it's a quality focused people +focused culture so if you if you do + + align:start position:0% +focused culture so if you if you do + + + align:start position:0% +focused culture so if you if you do +that um + + align:start position:0% +that um + + + align:start position:0% +that um +you know then then for sure Charlotte + + align:start position:0% +you know then then for sure Charlotte + + + align:start position:0% +you know then then for sure Charlotte +won't want to work there because not + + align:start position:0% +won't want to work there because not + + + align:start position:0% +won't want to work there because not +only do they straighten your tea they + + align:start position:0% +only do they straighten your tea they + + + align:start position:0% +only do they straighten your tea they +cut out child care they do all kinds of + + align:start position:0% +cut out child care they do all kinds of + + + align:start position:0% +cut out child care they do all kinds of +other things to cut + + align:start position:0% +other things to cut + + + align:start position:0% +other things to cut +costs you could either raise or lower + + align:start position:0% +costs you could either raise or lower + + + align:start position:0% +costs you could either raise or lower +all this stuff the service the technical + + align:start position:0% +all this stuff the service the technical + + + align:start position:0% +all this stuff the service the technical +people in the field they've got a + + align:start position:0% +people in the field they've got a + + + align:start position:0% +people in the field they've got a +probably a high- price Salesforce + + align:start position:0% +probably a high- price Salesforce + + + align:start position:0% +probably a high- price Salesforce +because they're all technical people you + + align:start position:0% +because they're all technical people you + + + align:start position:0% +because they're all technical people you +could go back to plain old salespeople + + align:start position:0% +could go back to plain old salespeople + + + align:start position:0% +could go back to plain old salespeople +you could cut out this manufacturer + + align:start position:0% +you could cut out this manufacturer + + + align:start position:0% +you could cut out this manufacturer +Advanced manufacturing center which + + align:start position:0% +Advanced manufacturing center which + + + align:start position:0% +Advanced manufacturing center which +nobody else has got you could stop + + align:start position:0% +nobody else has got you could stop + + + align:start position:0% +nobody else has got you could stop +working on Research or you could do more + + align:start position:0% +working on Research or you could do more + + + align:start position:0% +working on Research or you could do more +of all of + + align:start position:0% +of all of + + + align:start position:0% +of all of +those you could whoa that was + + align:start position:0% +those you could whoa that was + + + align:start position:0% +those you could whoa that was +cute uh bad button you could um uh + + align:start position:0% +cute uh bad button you could um uh + + + align:start position:0% +cute uh bad button you could um uh +decide that there really are scale + + align:start position:0% +decide that there really are scale + + + align:start position:0% +decide that there really are scale +economies in building your own inputs + + align:start position:0% +economies in building your own inputs + + + align:start position:0% +economies in building your own inputs +instead of buying them you could try to + + align:start position:0% +instead of buying them you could try to + + + align:start position:0% +instead of buying them you could try to +integrate upstream or you could do + + align:start position:0% +integrate upstream or you could do + + + align:start position:0% +integrate upstream or you could do +things I haven't thought + + align:start position:0% +things I haven't thought + + + align:start position:0% +things I haven't thought +of so instead of what would they do what + + align:start position:0% +of so instead of what would they do what + + + align:start position:0% +of so instead of what would they do what +should they do Sam you had a you were + + align:start position:0% +should they do Sam you had a you were + + + align:start position:0% +should they do Sam you had a you were +doing a should right you were you were + + align:start position:0% +doing a should right you were you were + + + align:start position:0% +doing a should right you were you were +saying they should focus on + + align:start position:0% +saying they should focus on + + + align:start position:0% +saying they should focus on +communicating the advantage to customers + + align:start position:0% +communicating the advantage to customers + + + align:start position:0% +communicating the advantage to customers +and I also think they + + align:start position:0% +and I also think they + + + align:start position:0% +and I also think they +probably should raise spending on like + + align:start position:0% +probably should raise spending on like + + + align:start position:0% +probably should raise spending on like +technology and quality and all that + + align:start position:0% +technology and quality and all that + + + align:start position:0% +technology and quality and all that +because that's what they're good at okay + + align:start position:0% +because that's what they're good at okay + + + align:start position:0% +because that's what they're good at okay +Max where are you going I think they + + align:start position:0% +Max where are you going I think they + + + align:start position:0% +Max where are you going I think they +should do an analysis of who their main + + align:start position:0% +should do an analysis of who their main + + + align:start position:0% +should do an analysis of who their main +customers are and they only make a + + align:start position:0% +customers are and they only make a + + + align:start position:0% +customers are and they only make a +couple hundred machines a year so if all + + align:start position:0% +couple hundred machines a year so if all + + + align:start position:0% +couple hundred machines a year so if all +those machines are going to the same + + align:start position:0% +those machines are going to the same + + + align:start position:0% +those machines are going to the same +customers or similar customers and they + + align:start position:0% +customers or similar customers and they + + + align:start position:0% +customers or similar customers and they +can probably Bank on loyalty and should + + align:start position:0% +can probably Bank on loyalty and should + + + align:start position:0% +can probably Bank on loyalty and should +focus on communicating the advantages + + align:start position:0% +focus on communicating the advantages + + + align:start position:0% +focus on communicating the advantages +because they can sell that but if a lot + + align:start position:0% +because they can sell that but if a lot + + + align:start position:0% +because they can sell that but if a lot +of those machines are going into new + + align:start position:0% +of those machines are going into new + + + align:start position:0% +of those machines are going into new +companies that are trying to look to + + align:start position:0% +companies that are trying to look to + + + align:start position:0% +companies that are trying to look to +reduce costs initially then they might + + align:start position:0% +reduce costs initially then they might + + + align:start position:0% +reduce costs initially then they might +want to think about cutting cost to stay + + align:start position:0% +want to think about cutting cost to stay + + + align:start position:0% +want to think about cutting cost to stay +competitive in that market so that's + + align:start position:0% +competitive in that market so that's + + + align:start position:0% +competitive in that market so that's +interesting so if it's the same + + align:start position:0% +interesting so if it's the same + + + align:start position:0% +interesting so if it's the same +customers then it's it's an advantage to + + align:start position:0% +customers then it's it's an advantage to + + + align:start position:0% +customers then it's it's an advantage to +the customer to have only one supplier + + align:start position:0% +the customer to have only one supplier + + + align:start position:0% +the customer to have only one supplier +to have husky machines throughout so if + + align:start position:0% +to have husky machines throughout so if + + + align:start position:0% +to have husky machines throughout so if +if the growth is coming from sales to + + align:start position:0% +if the growth is coming from sales to + + + align:start position:0% +if the growth is coming from sales to +customers that already have husky + + align:start position:0% +customers that already have husky + + + align:start position:0% +customers that already have husky +machines you could stress the fact that + + align:start position:0% +machines you could stress the fact that + + + align:start position:0% +machines you could stress the fact that +look I mean you got one supplier you've + + align:start position:0% +look I mean you got one supplier you've + + + align:start position:0% +look I mean you got one supplier you've +only got to have one set of spare ports + + align:start position:0% +only got to have one set of spare ports + + + align:start position:0% +only got to have one set of spare ports +you've only got to call one person when + + align:start position:0% +you've only got to call one person when + + + align:start position:0% +you've only got to call one person when +it breaks down be a Husky Shop but + + align:start position:0% +it breaks down be a Husky Shop but + + + align:start position:0% +it breaks down be a Husky Shop but +you're right it might be different if + + align:start position:0% +you're right it might be different if + + + align:start position:0% +you're right it might be different if +they're new people and they worry more + + align:start position:0% +they're new people and they worry more + + + align:start position:0% +they're new people and they worry more +about about upfront cost okay anybody + + align:start position:0% +about about upfront cost okay anybody + + + align:start position:0% +about about upfront cost okay anybody +else any other approaches + + align:start position:0% +else any other approaches + + + align:start position:0% +else any other approaches +Erica would it be unreasonable to like + + align:start position:0% +Erica would it be unreasonable to like + + + align:start position:0% +Erica would it be unreasonable to like +look into cutting costs while + + align:start position:0% +look into cutting costs while + + + align:start position:0% +look into cutting costs while +maintaining like quality so I guess like + + align:start position:0% +maintaining like quality so I guess like + + + align:start position:0% +maintaining like quality so I guess like +investing Research into like cutting + + align:start position:0% +investing Research into like cutting + + + align:start position:0% +investing Research into like cutting +cost but maining p + + align:start position:0% +cost but maining p + + + align:start position:0% +cost but maining p +well you what cut you'd cut + + align:start position:0% +well you what cut you'd cut + + + align:start position:0% +well you what cut you'd cut +manufacturing costs or you'd cut out the + + align:start position:0% +manufacturing costs or you'd cut out the + + + align:start position:0% +manufacturing costs or you'd cut out the +daycare center you wouldn't cut out the + + align:start position:0% +daycare center you wouldn't cut out the + + + align:start position:0% +daycare center you wouldn't cut out the +daycare okay like manufacturing costs + + align:start position:0% +daycare okay like manufacturing costs + + + align:start position:0% +daycare okay like manufacturing costs +like how to make how to produce things + + align:start position:0% +like how to make how to produce things + + + align:start position:0% +like how to make how to produce things +more efficiently so you'd Focus you'd + + align:start position:0% +more efficiently so you'd Focus you'd + + + align:start position:0% +more efficiently so you'd Focus you'd +focus on manufacturing costs would you + + align:start position:0% +focus on manufacturing costs would you + + + align:start position:0% +focus on manufacturing costs would you +also uh raise or this is a fair amount + + align:start position:0% +also uh raise or this is a fair amount + + + align:start position:0% +also uh raise or this is a fair amount +of cost in here uh having this + + align:start position:0% +of cost in here uh having this + + + align:start position:0% +of cost in here uh having this +high-priced field Force this Advanced + + align:start position:0% +high-priced field Force this Advanced + + + align:start position:0% +high-priced field Force this Advanced +manufacturing center the spending on + + align:start position:0% +manufacturing center the spending on + + + align:start position:0% +manufacturing center the spending on +Innovation that's a cost would you cut + + align:start position:0% +Innovation that's a cost would you cut + + + align:start position:0% +Innovation that's a cost would you cut +cost there or would you cut cost in + + align:start position:0% +cost there or would you cut cost in + + + align:start position:0% +cost there or would you cut cost in +focus on manufacturing cost well I mean + + align:start position:0% +focus on manufacturing cost well I mean + + + align:start position:0% +focus on manufacturing cost well I mean +I guess it I guess like from I was + + align:start position:0% +I guess it I guess like from I was + + + align:start position:0% +I guess it I guess like from I was +focusing on manufacturing cost okay I + + align:start position:0% +focusing on manufacturing cost okay I + + + align:start position:0% +focusing on manufacturing cost okay I +mean those daycare center stays but + + align:start position:0% +mean those daycare center stays but + + + align:start position:0% +mean those daycare center stays but +we're going to we're going to really try + + align:start position:0% +we're going to we're going to really try + + + align:start position:0% +we're going to we're going to really try +to get these things built more cheaply + + align:start position:0% +to get these things built more cheaply + + + align:start position:0% +to get these things built more cheaply +yeah okay and then would you use that to + + align:start position:0% +yeah okay and then would you use that to + + + align:start position:0% +yeah okay and then would you use that to +cut + + align:start position:0% +cut + + + align:start position:0% +cut +prices I mean you could and like I mean + + align:start position:0% +prices I mean you could and like I mean + + + align:start position:0% +prices I mean you could and like I mean +if you if like cutting prices reflects + + align:start position:0% +if you if like cutting prices reflects + + + align:start position:0% +if you if like cutting prices reflects +like lower quality like that would be + + align:start position:0% +like lower quality like that would be + + + align:start position:0% +like lower quality like that would be +bad yeah but like you could also stress + + align:start position:0% +bad yeah but like you could also stress + + + align:start position:0% +bad yeah but like you could also stress +that like it's you could like have like + + align:start position:0% +that like it's you could like have like + + + align:start position:0% +that like it's you could like have like +better quality machines or okay + + align:start position:0% +better quality machines or okay + + + align:start position:0% +better quality machines or okay +Jacqueline I was going to say agree with + + align:start position:0% +Jacqueline I was going to say agree with + + + align:start position:0% +Jacqueline I was going to say agree with +that that you could use that to cut + + align:start position:0% +that that you could use that to cut + + + align:start position:0% +that that you could use that to cut +prices but at the same time still + + align:start position:0% +prices but at the same time still + + + align:start position:0% +prices but at the same time still +highlight the quality of your product + + align:start position:0% +highlight the quality of your product + + + align:start position:0% +highlight the quality of your product +and that advantage to can do multiple + + align:start position:0% +and that advantage to can do multiple + + + align:start position:0% +and that advantage to can do multiple +strategy okay okay anybody who hasn't + + align:start position:0% +strategy okay okay anybody who hasn't + + + align:start position:0% +strategy okay okay anybody who hasn't +yeah um I'd say like increased services + + align:start position:0% +yeah um I'd say like increased services + + + align:start position:0% +yeah um I'd say like increased services +at the point of purchase so like they + + align:start position:0% +at the point of purchase so like they + + + align:start position:0% +at the point of purchase so like they +offer you know free installation or + + align:start position:0% +offer you know free installation or + + + align:start position:0% +offer you know free installation or +servicing of old husky machines for + + align:start position:0% +servicing of old husky machines for + + + align:start position:0% +servicing of old husky machines for +whenever you buy new ones or something + + align:start position:0% +whenever you buy new ones or something + + + align:start position:0% +whenever you buy new ones or something +like that to focus when they're going to + + align:start position:0% +like that to focus when they're going to + + + align:start position:0% +like that to focus when they're going to +buy a machine they're going to have it + + align:start position:0% +buy a machine they're going to have it + + + align:start position:0% +buy a machine they're going to have it +for a while so focusing like right on + + align:start position:0% +for a while so focusing like right on + + + align:start position:0% +for a while so focusing like right on +that point so I'm rais that's costing me + + align:start position:0% +that point so I'm rais that's costing me + + + align:start position:0% +that point so I'm rais that's costing me +money so how am I going to get it back + + align:start position:0% +money so how am I going to get it back + + + align:start position:0% +money so how am I going to get it back +or am I not Customer Loyalty just + + align:start position:0% +or am I not Customer Loyalty just + + + align:start position:0% +or am I not Customer Loyalty just +selling you're going to sell those + + align:start position:0% +selling you're going to sell those + + + align:start position:0% +selling you're going to sell those +machines I guess you have to lay that + + align:start position:0% +machines I guess you have to lay that + + + align:start position:0% +machines I guess you have to lay that +kind of back and forth but hopefully + + align:start position:0% +kind of back and forth but hopefully + + + align:start position:0% +kind of back and forth but hopefully +ends positive yeah I mean one approach + + align:start position:0% +ends positive yeah I mean one approach + + + align:start position:0% +ends positive yeah I mean one approach +here is to say game over uh I made a lot + + align:start position:0% +here is to say game over uh I made a lot + + + align:start position:0% +here is to say game over uh I made a lot +of money before people came into my + + align:start position:0% +of money before people came into my + + + align:start position:0% +of money before people came into my +segment and I'm not going to make that + + align:start position:0% +segment and I'm not going to make that + + + align:start position:0% +segment and I'm not going to make that +kind of money again so what I want to + + align:start position:0% +kind of money again so what I want to + + + align:start position:0% +kind of money again so what I want to +make sure is that I maintain a position + + align:start position:0% +make sure is that I maintain a position + + + align:start position:0% +make sure is that I maintain a position +through high service and whatever uh and + + align:start position:0% +through high service and whatever uh and + + + align:start position:0% +through high service and whatever uh and +don't get swamped I kind of Niche myself + + align:start position:0% +don't get swamped I kind of Niche myself + + + align:start position:0% +don't get swamped I kind of Niche myself +even a little more Charlotte well I + + align:start position:0% +even a little more Charlotte well I + + + align:start position:0% +even a little more Charlotte well I +think that like they are a very + + align:start position:0% +think that like they are a very + + + align:start position:0% +think that like they are a very +different company than their competitors + + align:start position:0% +different company than their competitors + + + align:start position:0% +different company than their competitors +right like they're focusing on this kind + + align:start position:0% +right like they're focusing on this kind + + + align:start position:0% +right like they're focusing on this kind +of assembly line manufacturer that + + align:start position:0% +of assembly line manufacturer that + + + align:start position:0% +of assembly line manufacturer that +allows them to specialize products for + + align:start position:0% +allows them to specialize products for + + + align:start position:0% +allows them to specialize products for +what their consumer wants so they could + + align:start position:0% +what their consumer wants so they could + + + align:start position:0% +what their consumer wants so they could +focus on that and even take that a + + align:start position:0% +focus on that and even take that a + + + align:start position:0% +focus on that and even take that a +little bit further and maybe like if + + align:start position:0% +little bit further and maybe like if + + + align:start position:0% +little bit further and maybe like if +there's a huge price difference in what + + align:start position:0% +there's a huge price difference in what + + + align:start position:0% +there's a huge price difference in what +their competitors are now charging to + + align:start position:0% +their competitors are now charging to + + + align:start position:0% +their competitors are now charging to +kind of like modify the machines and + + align:start position:0% +kind of like modify the machines and + + + align:start position:0% +kind of like modify the machines and +what they have been charging they could + + align:start position:0% +what they have been charging they could + + + align:start position:0% +what they have been charging they could +cut price a little so there's still a + + align:start position:0% +cut price a little so there's still a + + + align:start position:0% +cut price a little so there's still a +high + + align:start position:0% +high + + + align:start position:0% +high +quality uh company like like higher more + + align:start position:0% +quality uh company like like higher more + + + align:start position:0% +quality uh company like like higher more +luxury but not as much they would for + + align:start position:0% +luxury but not as much they would for + + + align:start position:0% +luxury but not as much they would for +because they were charging like really + + align:start position:0% +because they were charging like really + + + align:start position:0% +because they were charging like really +really high premiums too like they could + + align:start position:0% +really high premiums too like they could + + + align:start position:0% +really high premiums too like they could +just change that they could come down a + + align:start position:0% +just change that they could come down a + + + align:start position:0% +just change that they could come down a +bit I mean although the premium seem to + + align:start position:0% +bit I mean although the premium seem to + + + align:start position:0% +bit I mean although the premium seem to +be justified based on that analysis + + align:start position:0% +be justified based on that analysis + + + align:start position:0% +be justified based on that analysis +anybody over here Pedro I tend look left + + align:start position:0% +anybody over here Pedro I tend look left + + + align:start position:0% +anybody over here Pedro I tend look left +so you need to you need to wave your + + align:start position:0% +so you need to you need to wave your + + + align:start position:0% +so you need to you need to wave your +hand I also I was at the beginning I was + + align:start position:0% +hand I also I was at the beginning I was + + + align:start position:0% +hand I also I was at the beginning I was +also thinking of um the manufacturing + + align:start position:0% +also thinking of um the manufacturing + + + align:start position:0% +also thinking of um the manufacturing +cost of the machines like produce um + + align:start position:0% +cost of the machines like produce um + + + align:start position:0% +cost of the machines like produce um +that are more energy efficient um so + + align:start position:0% +that are more energy efficient um so + + + align:start position:0% +that are more energy efficient um so +that's um heat production cost so I was + + align:start position:0% +that's um heat production cost so I was + + + align:start position:0% +that's um heat production cost so I was +thinking at the beginning but then I was + + align:start position:0% +thinking at the beginning but then I was + + + align:start position:0% +thinking at the beginning but then I was +also thinking um just thought of um + + align:start position:0% +also thinking um just thought of um + + + align:start position:0% +also thinking um just thought of um +maybe expanding the market a little bit + + align:start position:0% +maybe expanding the market a little bit + + + align:start position:0% +maybe expanding the market a little bit +um like how about um because so the + + align:start position:0% +um like how about um because so the + + + align:start position:0% +um like how about um because so the +other c um the other companies produce + + align:start position:0% +other c um the other companies produce + + + align:start position:0% +other c um the other companies produce +more types of be blessing so I of so + + align:start position:0% +more types of be blessing so I of so + + + align:start position:0% +more types of be blessing so I of so +maybe go into some other segments okay + + align:start position:0% +maybe go into some other segments okay + + + align:start position:0% +maybe go into some other segments okay +let me let me give you a few thoughts + + align:start position:0% +let me let me give you a few thoughts + + + align:start position:0% +let me let me give you a few thoughts +they have a lot of choices here um and + + align:start position:0% +they have a lot of choices here um and + + + align:start position:0% +they have a lot of choices here um and +it's it's + + align:start position:0% +it's it's + + + align:start position:0% +it's it's +interesting looking at this whole menu + + align:start position:0% +interesting looking at this whole menu + + + align:start position:0% +interesting looking at this whole menu +one of the things I must say that struck + + align:start position:0% +one of the things I must say that struck + + + align:start position:0% +one of the things I must say that struck +me is before 1995 this is a great + + align:start position:0% +me is before 1995 this is a great + + + align:start position:0% +me is before 1995 this is a great +example of how all the pieces fit + + align:start position:0% +example of how all the pieces fit + + + align:start position:0% +example of how all the pieces fit +together they focused on a segment they + + align:start position:0% +together they focused on a segment they + + + align:start position:0% +together they focused on a segment they +figured out what that that that segment + + align:start position:0% +figured out what that that that segment + + + align:start position:0% +figured out what that that that segment +cares about performance they're all + + align:start position:0% +cares about performance they're all + + + align:start position:0% +cares about performance they're all +about performance and Technical + + align:start position:0% +about performance and Technical + + + align:start position:0% +about performance and Technical +Excellence they got a culture that fits + + align:start position:0% +Excellence they got a culture that fits + + + align:start position:0% +Excellence they got a culture that fits +with that all the pieces fit together + + align:start position:0% +with that all the pieces fit together + + + align:start position:0% +with that all the pieces fit together +it's Ikea it's um Southwest + + align:start position:0% +it's Ikea it's um Southwest + + + align:start position:0% +it's Ikea it's um Southwest +Airlines and comes now this this + + align:start position:0% +Airlines and comes now this this + + + align:start position:0% +Airlines and comes now this this +difficult time can you make the things + + align:start position:0% +difficult time can you make the things + + + align:start position:0% +difficult time can you make the things +fit together so a couple of + + align:start position:0% +fit together so a couple of + + + align:start position:0% +fit together so a couple of +choices their basic options I mean you + + align:start position:0% +choices their basic options I mean you + + + align:start position:0% +choices their basic options I mean you +can try to you can try to increase + + align:start position:0% +can try to you can try to increase + + + align:start position:0% +can try to you can try to increase +that's all is one of the entrance you + + align:start position:0% +that's all is one of the entrance you + + + align:start position:0% +that's all is one of the entrance you +will recall you can try to increase uh + + align:start position:0% +will recall you can try to increase uh + + + align:start position:0% +will recall you can try to increase uh +willingness to pay you can think about + + align:start position:0% +willingness to pay you can think about + + + align:start position:0% +willingness to pay you can think about +um uh more service more + + align:start position:0% +um uh more service more + + + align:start position:0% +um uh more service more +R&D the question Shad has to ask himself + + align:start position:0% +R&D the question Shad has to ask himself + + + align:start position:0% +R&D the question Shad has to ask himself +one of the questions is is there room + + align:start position:0% +one of the questions is is there room + + + align:start position:0% +one of the questions is is there room +for + + align:start position:0% +for + + + align:start position:0% +for +that right differentiation makes you + + align:start position:0% +that right differentiation makes you + + + align:start position:0% +that right differentiation makes you +money if it's cost effective so the + + align:start position:0% +money if it's cost effective so the + + + align:start position:0% +money if it's cost effective so the +question is how much more service what + + align:start position:0% +question is how much more service what + + + align:start position:0% +question is how much more service what +would you get from increased service the + + align:start position:0% +would you get from increased service the + + + align:start position:0% +would you get from increased service the +question of thinking about who your + + align:start position:0% +question of thinking about who your + + + align:start position:0% +question of thinking about who your +customers are are they are they repeat + + align:start position:0% +customers are are they are they repeat + + + align:start position:0% +customers are are they are they repeat +is this the same people expanding is it + + align:start position:0% +is this the same people expanding is it + + + align:start position:0% +is this the same people expanding is it +new people what's the return to that you + + align:start position:0% +new people what's the return to that you + + + align:start position:0% +new people what's the return to that you +could improve the cost position remember + + align:start position:0% +could improve the cost position remember + + + align:start position:0% +could improve the cost position remember +these two basic approaches you can + + align:start position:0% +these two basic approaches you can + + + align:start position:0% +these two basic approaches you can +differentiate you can lower + + align:start position:0% + + + + align:start position:0% + +cost can you cut cost and still + + align:start position:0% +cost can you cut cost and still + + + align:start position:0% +cost can you cut cost and still +deliver if you cut the perks cut the + + align:start position:0% +deliver if you cut the perks cut the + + + align:start position:0% +deliver if you cut the perks cut the +Salesforce will you affect the culture + + align:start position:0% +Salesforce will you affect the culture + + + align:start position:0% +Salesforce will you affect the culture +can you continue to deliver if you do an + + align:start position:0% +can you continue to deliver if you do an + + + align:start position:0% +can you continue to deliver if you do an +aggressive cost cut and you can cut + + align:start position:0% +aggressive cost cut and you can cut + + + align:start position:0% +aggressive cost cut and you can cut +margins they've got pretty good margins + + align:start position:0% +margins they've got pretty good margins + + + align:start position:0% +margins they've got pretty good margins +they've got room to cut + + align:start position:0% +they've got room to cut + + + align:start position:0% +they've got room to cut +margins + + align:start position:0% +margins + + + align:start position:0% +margins +um but to become the lowcost producer + + align:start position:0% +um but to become the lowcost producer + + + align:start position:0% +um but to become the lowcost producer +probably not the they could go after + + align:start position:0% +probably not the they could go after + + + align:start position:0% +probably not the they could go after +other segments they only serve part of + + align:start position:0% +other segments they only serve part of + + + align:start position:0% +other segments they only serve part of +the business they could grow by going to + + align:start position:0% +the business they could grow by going to + + + align:start position:0% +the business they could grow by going to +other segments but given that they're a + + align:start position:0% +other segments but given that they're a + + + align:start position:0% +other segments but given that they're a +high-cost company and have a particular + + align:start position:0% +high-cost company and have a particular + + + align:start position:0% +high-cost company and have a particular +culture the question you'd have to ask + + align:start position:0% +culture the question you'd have to ask + + + align:start position:0% +culture the question you'd have to ask +is does that fit can we do + + align:start position:0% +is does that fit can we do + + + align:start position:0% +is does that fit can we do +that and + + align:start position:0% +that and + + + align:start position:0% +that and +then you you would like the whole + + align:start position:0% +then you you would like the whole + + + align:start position:0% +then you you would like the whole +package to + + align:start position:0% +package to + + + align:start position:0% +package to +fit and at this + + align:start position:0% +fit and at this + + + align:start position:0% +fit and at this +point how old was Shad Shad was 67 in + + align:start position:0% +point how old was Shad Shad was 67 in + + + align:start position:0% +point how old was Shad Shad was 67 in +19995 so as someone in that age bracket + + align:start position:0% +19995 so as someone in that age bracket + + + align:start position:0% +19995 so as someone in that age bracket +let me just say uh he obviously has to + + align:start position:0% +let me just say uh he obviously has to + + + align:start position:0% +let me just say uh he obviously has to +think about what am I handing off am I + + align:start position:0% +think about what am I handing off am I + + + align:start position:0% +think about what am I handing off am I +going to create something that's going + + align:start position:0% +going to create something that's going + + + align:start position:0% +going to create something that's going +to go on because he's not going to be + + align:start position:0% +to go on because he's not going to be + + + align:start position:0% +to go on because he's not going to be +leading that well one assumes he's not + + align:start position:0% +leading that well one assumes he's not + + + align:start position:0% +leading that well one assumes he's not +going to be an active participant for + + align:start position:0% +going to be an active participant for + + + align:start position:0% +going to be an active participant for +another 20 + + align:start position:0% +another 20 + + + align:start position:0% +another 20 +years + + align:start position:0% +years + + + align:start position:0% +years +so what he + + align:start position:0% +so what he + + + align:start position:0% +so what he +did was actually quite + + align:start position:0% + + + + align:start position:0% + +drastic I don't know whether this was + + align:start position:0% +drastic I don't know whether this was + + + align:start position:0% +drastic I don't know whether this was +right or wrong but this is what he did + + align:start position:0% +right or wrong but this is what he did + + + align:start position:0% +right or wrong but this is what he did +they went into other other uh niches + + align:start position:0% +they went into other other uh niches + + + align:start position:0% +they went into other other uh niches +they moved out they increased their + + align:start position:0% +they moved out they increased their + + + align:start position:0% +they moved out they increased their +manufacturing capacity substantially + + align:start position:0% +manufacturing capacity substantially + + + align:start position:0% +manufacturing capacity substantially +they thought they were too small for + + align:start position:0% +they thought they were too small for + + + align:start position:0% +they thought they were too small for +scale so they added capacity they cut + + align:start position:0% +scale so they added capacity they cut + + + align:start position:0% +scale so they added capacity they cut +prices + + align:start position:0% +prices + + + align:start position:0% +prices +dramatically in response to low price + + align:start position:0% +dramatically in response to low price + + + align:start position:0% +dramatically in response to low price +entrance probably isn't going to keep + + align:start position:0% +entrance probably isn't going to keep + + + align:start position:0% +entrance probably isn't going to keep +them out they work to cut + + align:start position:0% +them out they work to cut + + + align:start position:0% +them out they work to cut +costs cutting prices it was argued was a + + align:start position:0% +costs cutting prices it was argued was a + + + align:start position:0% +costs cutting prices it was argued was a +way to put pressure on + + align:start position:0% +way to put pressure on + + + align:start position:0% +way to put pressure on +costs and a hope you can keep the + + align:start position:0% +costs and a hope you can keep the + + + align:start position:0% +costs and a hope you can keep the +culture you basically say to your people + + align:start position:0% +culture you basically say to your people + + + align:start position:0% +culture you basically say to your people +look we're getting killed on price we've + + align:start position:0% +look we're getting killed on price we've + + + align:start position:0% +look we're getting killed on price we've +got a match and the only way we're going + + align:start position:0% +got a match and the only way we're going + + + align:start position:0% +got a match and the only way we're going +to make any money as if we can find a + + align:start position:0% +to make any money as if we can find a + + + align:start position:0% +to make any money as if we can find a +way to get the cost down but they didn't + + align:start position:0% +way to get the cost down but they didn't + + + align:start position:0% +way to get the cost down but they didn't +decrease R&D they didn't decrease the + + align:start position:0% +decrease R&D they didn't decrease the + + + align:start position:0% +decrease R&D they didn't decrease the +manufacturing center they didn't + + align:start position:0% +manufacturing center they didn't + + + align:start position:0% +manufacturing center they didn't +decrease the sales force they began to + + align:start position:0% +decrease the sales force they began to + + + align:start position:0% +decrease the sales force they began to +build more in + + align:start position:0% +build more in + + + align:start position:0% +build more in +house and they had an + + align:start position:0% +house and they had an + + + align:start position:0% +house and they had an +IPO sold off the company in 1968 how + + align:start position:0% +IPO sold off the company in 1968 how + + + align:start position:0% +IPO sold off the company in 1968 how +well do you think this package + + align:start position:0% + + + + align:start position:0% + +worked saying words not so well yeah I + + align:start position:0% +worked saying words not so well yeah I + + + align:start position:0% +worked saying words not so well yeah I +mean also with hindsight I would argue + + align:start position:0% +mean also with hindsight I would argue + + + align:start position:0% +mean also with hindsight I would argue +that you'd have globalization in the + + align:start position:0% +that you'd have globalization in the + + + align:start position:0% +that you'd have globalization in the +early 21st century as well so I would + + align:start position:0% +early 21st century as well so I would + + + align:start position:0% +early 21st century as well so I would +argue that the R cost manufacturers in + + align:start position:0% +argue that the R cost manufacturers in + + + align:start position:0% +argue that the R cost manufacturers in +the US would get undercut by Chinese + + align:start position:0% +the US would get undercut by Chinese + + + align:start position:0% +the US would get undercut by Chinese +manufacturers and the best way to stay + + align:start position:0% +manufacturers and the best way to stay + + + align:start position:0% +manufacturers and the best way to stay +competitive was to stay high cost high + + align:start position:0% +competitive was to stay high cost high + + + align:start position:0% +competitive was to stay high cost high +high quality yeah I mean it's a curious + + align:start position:0% +high quality yeah I mean it's a curious + + + align:start position:0% +high quality yeah I mean it's a curious +It's a curious mixture isn't it because + + align:start position:0% +It's a curious mixture isn't it because + + + align:start position:0% +It's a curious mixture isn't it because +the company was built for high cost high + + align:start position:0% +the company was built for high cost high + + + align:start position:0% +the company was built for high cost high +quality + + align:start position:0% +quality + + + align:start position:0% +quality +and they tried to position themselves as + + align:start position:0% +and they tried to position themselves as + + + align:start position:0% +and they tried to position themselves as +the high cost high quality firm across + + align:start position:0% +the high cost high quality firm across + + + align:start position:0% +the high cost high quality firm across +the market in all of these + + align:start position:0% +the market in all of these + + + align:start position:0% +the market in all of these +niches even though in a bunch of the + + align:start position:0% +niches even though in a bunch of the + + + align:start position:0% +niches even though in a bunch of the +niches quality wasn't that + + align:start position:0% +niches quality wasn't that + + + align:start position:0% +niches quality wasn't that +important + + align:start position:0% + + + + align:start position:0% + +so I've seen numbers through 1999 and + + align:start position:0% +so I've seen numbers through 1999 and + + + align:start position:0% +so I've seen numbers through 1999 and +they continued to grow because the + + align:start position:0% +they continued to grow because the + + + align:start position:0% +they continued to grow because the +business grew their profitability was + + align:start position:0% +business grew their profitability was + + + align:start position:0% +business grew their profitability was +not + + align:start position:0% +not + + + align:start position:0% +not +terrific it was pretty erratic because + + align:start position:0% +terrific it was pretty erratic because + + + align:start position:0% +terrific it was pretty erratic because +they're changing the company rather + + align:start position:0% +they're changing the company rather + + + align:start position:0% +they're changing the company rather +dramatically and you can't get any more + + align:start position:0% +dramatically and you can't get any more + + + align:start position:0% +dramatically and you can't get any more +numbers because they went private last + + align:start position:0% +numbers because they went private last + + + align:start position:0% +numbers because they went private last +year so their website now is just an + + align:start position:0% +year so their website now is just an + + + align:start position:0% +year so their website now is just an +advertisement for their technology they + + align:start position:0% +advertisement for their technology they + + + align:start position:0% +advertisement for their technology they +no numbers available because they're a + + align:start position:0% +no numbers available because they're a + + + align:start position:0% +no numbers available because they're a +privately held + + align:start position:0% +privately held + + + align:start position:0% +privately held +company they're still in Bolton + + align:start position:0% +company they're still in Bolton + + + align:start position:0% +company they're still in Bolton +Ontario um questions comments reactions + + align:start position:0% +Ontario um questions comments reactions + + + align:start position:0% +Ontario um questions comments reactions +thoughts yeah they go private by some + + align:start position:0% +thoughts yeah they go private by some + + + align:start position:0% +thoughts yeah they go private by some +sort of buyout because of Po performance + + align:start position:0% +sort of buyout because of Po performance + + + align:start position:0% +sort of buyout because of Po performance +uh you know the website doesn't say we + + align:start position:0% +uh you know the website doesn't say we + + + align:start position:0% +uh you know the website doesn't say we +went private because we were performing + + align:start position:0% +went private because we were performing + + + align:start position:0% +went private because we were performing +poorly the website just says such and + + align:start position:0% +poorly the website just says such and + + + align:start position:0% +poorly the website just says such and +such a private Equity Firm bought them + + align:start position:0% +such a private Equity Firm bought them + + + align:start position:0% +such a private Equity Firm bought them +uh I I don't think that's implausible + + align:start position:0% +uh I I don't think that's implausible + + + align:start position:0% +uh I I don't think that's implausible +but I don't know it's not implausible + + align:start position:0% +but I don't know it's not implausible + + + align:start position:0% +but I don't know it's not implausible +that this strategy that a private that a + + align:start position:0% +that this strategy that a private that a + + + align:start position:0% +that this strategy that a private that a +private Equity Firm said this strategy + + align:start position:0% +private Equity Firm said this strategy + + + align:start position:0% +private Equity Firm said this strategy +is a loser and we can make this firm + + align:start position:0% +is a loser and we can make this firm + + + align:start position:0% +is a loser and we can make this firm +more profitable by changing strategy but + + align:start position:0% +more profitable by changing strategy but + + + align:start position:0% +more profitable by changing strategy but +I don't know that okay see you all next + + align:start position:0% +I don't know that okay see you all next + + + align:start position:0% +I don't know that okay see you all next +time \ No newline at end of file diff --git a/Fnsu19QD1D8.txt b/Fnsu19QD1D8.txt new file mode 100644 index 0000000000000000000000000000000000000000..b049ba7d5393632cef07bf395c7c461643d885ee --- /dev/null +++ b/Fnsu19QD1D8.txt @@ -0,0 +1,3300 @@ +The following +content is provided + +under a Creative +Commons license. + +Your support will help MIT +OpenCourseWare continue + +to offer high-quality +educational resources for free. + +To make a donation or +view additional materials + +from hundreds of MIT courses, +visit MIT OpenCourseWare + +at ocw.mit.edu. + +PROFESSOR: OK. + +Here is the menu for today. + +We're discussing line +shifts and line broadening. + +And I want to finish +up today this chapter + +by describing collisional +narrowing, also called + +Dicke narrowing. + +Then I want to have +two more shorter topics + +on two other aspects which +lead to important line shapes + +and line broadening. + +So I want to quickly discuss +the spectrum of emitted light + +by an atom. + +And I want to discuss +collisional broadening. + +None of that will +be done in-depth. + +The spectrum of emitted +light is really open-ended, + +and we will have a more +advanced treatment in 8.422. + +But I do feel if I show you +all are kinds of line shifts + +and line broadening, +I should at least + +mention here the basic things. + +And collisional +broadening, I'm not + +sure how many atomic +physics courses + +you will find which teach +about collision broadening, + +because this is the physics +from gas discharge lamps, + +the old-fashioned physics. + +However, I've realized +that a lot of people + +know now about clock shifts, +and mean field broadening, + +and mean field, and +the ultra-cold gases. + +And they have no idea that +similar physics actually + +happens in ordinary gas. + +So at least in terms of +broadening your understanding, + +I want to talk just 10 minutes +about collisional broadening. + +I've completely eliminated +from this course + +the quantitative description +about collisional broadening, + +but I want to show +you a few cartoons + +and put some pictures +into your mind. + +And probably, we have time to +start the next chapter, which + +is actually a pretty short +one, on two-photon transitions. + +For me, actually, +Dicke narrowing + +is really the highlight +of the course, + +because it provides +conceptual insight + +into what really +line broadening is, + +and to realize that collisions +can narrow lines and not + +just broaden them. + +This is sort of +subtle and insightful. + +And similar to photon +transitions, it's short, + +but I hope it's also a +highlight, because there's + +so many people-- you and other +people-- who are sometimes + +struggling-- a photon is +absorbed and is emitted. + +Usually, the photon +is not absorbed, + +the photon is scattered. + +And whenever you think +about photon in, photon out, + +you really should think +about two-photon transitions. + +So the framework of +two-photon transitions + +allows me now to give you the +tools how you should really + +think about whenever you have +atoms interacting with light. + +The light is not absorbed, +the light is just scattered. + +And so you need that. + +On the other hand, based +on all the descriptions + +I've given you about +light-atom interaction, + +two-photon +transitions would just + +mean we need one more order +of perturbation theory, + +and then it's the same thing +you have already learned. + +So it's a highlight, and it's +to some extent also a review. + +You will actually recognize, in +some situations, the difference + +between two-photon processes +and one-photon processes. + +It's not so big, it's just +you have to-- you'll see. + +You have to use a +different Rabi frequency + +and some different concepts. + +OK. + +So that's, I think, really +an agenda of highlights. + +Let's go back to the physical +picture we drew up on Wednesday + +about Dicke narrowing. + +I just explained +to you that when + +we have an atom which is +trapped and tightly confined, + +that the spectrum consists of +a sharp light and sidebands. + +And now I was addressing +the situation-- + +what happens if you +have an atom which + +is surrounded by buffer gas? + +I would say, well, that's a +cheap trap created by nature, + +because when the particle +wants to fly away, + +it collides with +a buffer gas atom. + +So it stays put. + +So it's a cheap trap, but +it's also a lousy trap, + +because there is some randomness +in the number of collisions. + +But I'm waving my +arm, so that maybe you + +can go along with the picture +that it is an ensemble of traps + +which have very different +trap frequencies. + +And then we would expect, +based on our understanding + +of the spectrum of +confined particles, + +that we have a carrier, +which is always the same, + +at the electronic +excitation frequency. + +But then we have sidebands +at the trap frequency. + +But those sidebands +are now smeared out, + +because we do not have a +defined harmonic oscillator + +potential here. + +So therefore, I sort of +tried to lead you in the way + +that that may be one way how you +can think about the situation. + +And well, now I want to give you +a different way to look at it. + +And let's see how those +things come together. + +So if I would ask you, give +me a quantitative estimate + +how wide this line +is, do you have + +any idea how we can do that? + +Or let me even put it this way. + +It's again one of +those kind of things-- + +you have the knowledge, but +to put it together is hard. + +But I would guarantee +everybody in this room + +has the knowledge to write +down in one line what + +is the width of this line. + +What is the width of this line? + +It's an inverse time. + +What time? + +Coherence time. + +Yeah. + +But now, if you have an +atom which is now starting + +and it hits buffer +gas, how would you + +estimate the coherence time? + +AUDIENCE: Mean free pass. + +PROFESSOR: Mean free +pass will be important. + +But the coherence +time-- how long + +will the atom talk to the laser +beam in a phase-coherent way? + +So what do we have to +compare to the wavelengths? + +AUDIENCE: Mean free pass. + +PROFESSOR: The mean free pass. + +This will be the +important parameter. + +But if the mean free +pass is much shorter + +than the wavelengths? + +Well, the atom has just +moved a tiny bit, one mean. + +Is it still coherent +at this time? + +AUDIENCE: It's +shorter than the wave. + +PROFESSOR: If the mean free +path is shorter than the wave. + +So it will do many collisions. + +But since it stays localized, it +will still coherently interact. + +When will it stop +coherently interacting? + +AUDIENCE: Mean free path. + +PROFESSOR: No, the mean +free path is always smaller. + +Let's just assume that. + +I hear "diffusion." + +AUDIENCE: [INAUDIBLE]. + +PROFESSOR: Yes. + +The atom has a short +mean free path, + +but it will do a random walk. + +And the movement it diffuses +by more than a wavelength, + +it has randomly changed its +position by a wavelength. + +And that would +mean it experiences + +the phase of the drive +field in a random way. + +End of coherence. + +1 over this time +is its line width. + +OK. + +So let me write that down. + +So based on the +concepts we have learned + +by looking at Doppler +broadening and all that, + +we realize the +important aspect is, + +when do atoms in an ensemble +randomly move by a wavelength? + +So therefore, our +estimate is now-- + +estimate the widths +of the sharp peak. + +We use a model +which is diffusion. + +We know that in diffusion, +the random walk, the RMS + +position in atom has moved away. + +Ballistic motion +is linear in time. + +Diffusive motion is the +square root of time, + +or z square is linear in time. + +And we have the +diffusion constant. + +Diffusion by, well, +lambda or lambda + +bar after time, which +is wavelength squared. + +So therefore, we would +expect that the full width + +at 1/2 maximum of our peak +is k squared-- k, the wave + +vector of the light, and D +is the diffusion constant. + +Well, since you mentioned +the mean free path, let me, + +already at this point-- I +wanted to do it earlier, + +but it fits in very well here. + +In an ideal gas, the +diffusion constant + +is given by some thermal average +speed times the mean free path. + +And if you look +up some textbooks, + +there's a factor of 3. + +So our delta omega, +which is k squared + +D. Let me write it +as k times v bar. + +And the other k I write +as 1 over lambda bar. + +So this is k squared, +and I need l. + +So this is nothing +else than k squared-- + +I take this expression, +k squared l. + +This is one k, this +is the other k. + +And v bar times l is +the ideal gas expression + +for the diffusion constant. + +But now you realize that k, dot, +v-- since in a gas, the most + +probably velocity is +also the momentum spread, + +this is nothing else +than the Doppler width. + +So therefore, we find +that the line widths + +in Dicke narrowing-- +if we have buffer gas + +and we have diffusive +motion-- is much smaller-- + +and this is why it's +called Dicke narrowing-- + +than the Doppler broadening +if the mean free path is + +much smaller than +the wavelength. + +So this is where the +mean free path comes in. + +What happens if +the mean free path + +is much longer than +the wavelength? + +What line widths do we then get? + +Do we then have a +line width which + +is larger than the +Doppler broadening, + +or do we get the +Doppler broadening? + +Let's have a clicker question. + +So if l is much smaller +than lambda bar, + +is delta omega-- and this +is your option A-- equal to? + +Or option B, larger? + +OK. + +So what do you think? + +It's always a question +when we derive something, + +how seriously you should +take what we derived. + +So this expression +for delta omega Dicke + +shows that the line width +would get larger and larger + +the longer the +mean free path is. + +And the question is, +is that correct or not? + +OK. + +Any more takers? + +Whoops. + +Oops. + +Sorry, press again. + +I erased it by clicking +the wrong button. + +You've already +made up your mind. + +You know the answer. + +So stop, display. + +Yes. + +The majority answer +is definitely correct. + +What happens until the +first collision happens, + +you just have +normal Doppler-- you + +don't have diffusive motion, +you have ballistic motion. + +And if the line width is already +determined once the atoms have + +spread out by a wavelength, +that's it already. + +And then if then the particles +collide, it doesn't matter. + +So what we have assumed +is we've assumed + +that the relevant model for +the spread out to a wavelength + +is a diffusive model. + +And if we are past that-- +because the mean free path is + +larger than the +wavelength-- we have + +to go back to normal +Doppler broadening. + +OK. + +But now let me calculate +Dicke narrowing + +by using the formalism +we have developed. + +So let's use the correlation +function for that. + +And we know that the line +width was nothing else + +than the Fourier transform +of the correlation function, + +how the atoms +experience the drive + +field at two different times. + +So we had here the +matrix element, + +the Rabi frequency squared. + +We have between time +t and t plus tau, + +the phase of the drive +field accumulates + +e to the i omega tau. + +But now we have the e +to the minus ikr factor. + +And r, or the position-- +in diffusion, you + +often call it s-- changes now, +because the particle undergoes + +a random walk. + +So what we have to do is to +describe collisional narrowing, + +we have to take this +factor and average it + +over our ensemble of +diffusing particles. + +And well, diffusion means that +if particles start out at t + +equals 0 at the +origin, the probability + +that we find the +particle at time t, + +a distance s away +from the origin-- + +so I'm depicting this one here. + +The particle does +sort of a random walk. + +And after time t, it +is out at a position s. + +And the probability for +that is e to the minus + +s squared over 4 Dt. + +And you see it's s +is quadratic over t. + +This is a random walk. s +increases s's square root + +of time. + +And the probability is +normalized by this expression. + +So therefore, this red average +in the correlation function + +is calculated by convoluting +with this probability + +distribution for +the random walk. + +So it is e to the minus +iks, e to the minus + +s squared over 4 D. The +time is now called tau. + +We used to integrate +over all possibilities. + +And e to the i omega +tau is a common factor. + +My notes show that the integral +is done from minus infinity + +to plus infinity. + +Either this is right, or +there's a factor of two + +to be accounted, because +well, it depends. + +Now, is s a coordinate, +or is s in radians? + +In one case, it has a sign, +in the other case, it has not. + +I'm not able to +reconstruct it now, + +but it's just a +numerical factor, + +which would be affected by that. + +So the result of +this integral is + +that we obtain an +exponential function. + +So what we find out +is that there is now + +an exponentially +decaying function. + +Remember, we had situations +where the correlation function + +for how the atom +experiences a coherent field + +was decaying +exponentially because + +of spontaneous lifetime? + +And now we have an +exponential decay, + +because the particle +is defusing around. + +But we also know, of course, +that exponential decay, when + +we Fourier analyze it, +gives us a Lorentzian. + +So when we ask what is the +rate, Fermi's golden rule's + +rate expression, the +rate for excitation. + +We want to do the Fourier +transform of this correlation + +function. + +And what we obtain is, well, +a Lorentzian which looks + +like the Lorentzian for +spontaneous emission, + +except for that we have +a different width now. + +It's a Lorentzian with a +width 2 k squared times D. + +So pretty straightforward. + +But I hope you've +seen and you've + +enjoyed there's a very +intuitive picture. + +But the correlation +function-- if you just + +look at it from the +perspective of the atoms, + +how do I experience +a coherent field? + +You put in simply +the diffusive motion. + +You can exactly calculate +what the line shape is. + +And that's definitely +something you would not + +have known how to do it +without this formalism. + +OK. + +I have a question for you. + +And this is, how does the +spectrum for diffusive motion + +look like? + +What we have just +calculated was that it + +is a Lorentzian with the line +widths we've just determined. + +But I want to give +you another choice. + +And this is what we discussed +at the end of the last class. + +This picture where we took +the confined particles + +to the ridiculous limit-- where +there was no trap anymore, + +just collisions-- +suggested actually + +that we have some sharp line. + +But then this envelope +of those sidebands + +give some unresolved pedestal. + +So the question is, +what is correct? + +We have just done a +quantitative calculation + +using the model, a +diffusion propagator. + +But we also had this +intuitive picture, + +which had more this kind +of bimodal distribution. + +A broad pedestal +and a sharp peak. + +And I want you to think +about it for a few seconds. + +What would you expect to +be the correct answer? + +Is the line shape +just a Lorentzian, + +or does the line shape have +two different parts to it? + +OK. + +Does somebody want to speak out +in favor of his or her choice? + +Well, one argument is, +when you derive something, + +it must be more correct than +when you wave your hands. + +Therefore, we +derived a Lorentzian, + +and the other picture +was just waving our hands + +and using some analogy. + +OK. + +That would be one +argument to vote + +for A. Somebody +wants to defend B? + +Pardon? + +AUDIENCE: More intuitive. + +PROFESSOR: More intuitive. + +Yes. + +You know, something +must be right about it. + +I mean, in some limit, +this must be like a trap, + +and there should +be some sidebands. + +Yes. + +OK. + +But now I would ask you-- Nancy, +if you say it's more intuitive, + +why don't we get +those broadening? + +Why don't we get +this extra pedestal + +in our quantitative derivation? + +AUDIENCE: [INAUDIBLE]. + +PROFESSOR: But what? + +Didn't we lose the exact +probability distribution + +for diffusive process? + +AUDIENCE: There's no +harmonic oscillator. + +The sidebands [INAUDIBLE] +harmonic oscillator. + +PROFESSOR: So that's +an argument also for A. + +We don't have a +harmonic oscillator. + +And when I said there is sort +of this trap-type feature, + +I'm really over-extending +the analogy. + +AUDIENCE: The mean +free path is not-- + +PROFESSOR: Pardon? + +AUDIENCE: The mean free path +is not infinitesimally small. + +PROFESSOR: The mean free path +is not infinitesimally small. + +Now we're getting close. + +We assumed diffusive motion. + +We put in the exact expression +for diffusive motion. + +And of course, you also know, +when you describe a line width, + +what happens in the +middle at detuning + +0 is more what happens in +the limit of long times. + +What happens further and further +out happens at shorter times. + +What is the motion of +atoms at short times? + +Before the first collision +happens, it moves straight. + +So the diffusive +propagator which we put in + +is only valid after +the first collision. + +Until the first collision +happens, we have free motion. + +And free motion should give rise +to simple Doppler broadening. + +So until the first +collision happens, + +we should get a little +bit of Doppler broadening. + +But once the +collisions happened, + +we should be very well +within the description + +of the diffusion operator. + +And to address your +concern, actually, + +in the limit of many +sideband, often, + +the envelope of +all those sidebands + +is actually determined +by the Doppler profile. + +There is a limit, if you have +a large modulation index, + +that you have many sidebands. + +And in some +semi-classical limit, + +the sidebands have an envelope +which is the Doppler profile. + +So now I think the +two pictures agree. + +If we had used a propagator +which would interpolate + +between the first moment where +the particle moves straight, + +and then diffusion, we would +have gotten little pedestals + +here. + +And so that sort of tells us +that the smeared outside bands, + +yes, strictly speaking, they +are linked to harmonic motion. + +But they are sort +of the leftover + +of the motional effect, +which is the Doppler effect. + +OK. + +Good. + +So we have the +correct answer here. + +And here, it is the model +neglects ballistic motion + +until the first collision. + +Questions? + +OK. + +Let's now spend 10 +minutes discussing + +the fluorescent +spectrum of an atom. + +As I pointed out in my overview, +we teach much more about it + +in 8.422. + +We use a dressed atom picture. + +But something would be missing +if I wouldn't do it also + +in this course, because +we have discussed + +to quite some extent what +happens when we excite atoms + +with light. + +And what we have +discussed so far + +is that we excite atom and scan +the laser, or the excitation + +frequency. + +And when we are plotting the +intensity of the fluorescence, + +we are looking at the +number of scattered photon. + +And what we are scanning is +the detuning of the laser. + +We would expect, in the case +of a motionless atom, simply + +a Lorentzian, or in +the general limit, + +a power-broadened Lorentzian. + +Just to be clear, what I'm +discussing in those 10 minutes + +is I'm completely ignoring +that the atom can move. + +So you should think +that it's either + +an atom with infinite mass, +or it's an atom tightly + +localized in the +Lamb-Dicke limit, + +and all we are looking at is the +structure of the central peak. + +So no motional effects. + +We just look at the pure +kind of intrinsic line + +widths of the +electronic transition. + +OK. + +So we have discussed that. + +But now I want to look at +another aspect of spectroscopy. + +And this is another +scan we can do. + +We want to have +a fixed detuning. + +And we look at the spectrum +of the emitted light. + +So let's assume that +we have a laser which + +is at a detuning delta. + +The laser is fixed. + +The light is emitting. + +But we are now dispersing +with a spectrograph. + +We are analyzing what is the +frequency of the emitted light. + +And we determine the spectrum. + +And yes, the question is, +how does it look like? + +And I want to give +you four options. + +So this is 0 detuning +at resonance. + +Oops, I need one more. + +Let me relabel it +to make it clear. + +So our option one +is our spectrum + +is a delta function at +the resonance of the atom. + +Option two is it is a Lorentzian +centered around the resonance. + +Option three is it is a +delta function at the laser + +frequency. + +And option four is it is a +Lorentzian with line width + +gamma. + +So we have two options. + +Is it a delta function +at omega 0 or omega l? + +Or is it a Lorentzian-broadened +function at either omega 0 + +or omega l. + +And since we want to +keep things simple, + +we want to first discuss the +case of the perturbative case + +that the laser which excites +the atom has very low power. + +So what would you expect? + +An atom is excited, it's +a little light bulb. + +You analyze the spectrum +of the light bulb. + +Which of the four +spectrum will you measure? + +OK. + +Let's try again. + +[LAUGHTER] + +And maybe I should, like +our online learning system, + +try to give you one hint. + +I want you to really think hard +what energy conservation means + +in this problem. + +OK. + +OK, we're getting closer. + +Now, the way how I want +you to think about it + +is if you take the +limit of low power, + +you should really think +about it that there + +is only one photon in +your whole laboratory. + +This photon is +scattered of an atom, + +and then you measure the +frequency of the photon. + +And energy conservation clearly +tells us that the frequency + +of the scattered photon cannot +be at the resonance frequency. + +It has to be at the +laser frequency. + +Otherwise, we would +violate energy. + +But it seems-- still, +the more subtle thing + +is, is it a delta function? + +Of course, a delta +function will be broadened. + +If you do the experiment +for one second, + +you will have a Fourier +line width which is 1 hertz. + +But that's, for +practical reasons, almost + +like a delta function, because +the spectral line widths, + +or the natural line widths +of your favorite atom + +is 10 megahertz. + +So there will be some +temporal broadening, + +which is in case in any +realistic experiment. + +But we are talking about, are +you limited by the experiment + +and by technical +noise, or are you + +limited by the +natural line widths? + +Now, I would argue, just +with energy conservation-- + +but I'll give you another +argument in a second-- + +that if I have a +monochromatic laser, + +the photon which +has to come out has + +to be exactly the +same frequency. + +Because we talked about +energy conservation. + +And if I would start with a +photon at the laser frequency + +and I would measure a photon +which has 10 megahertz away, + +I would violate energy +conservation by 10 megahertz. + +So the argument is +actually correct. + +It's a delta function +at the drive frequency. + +But I want to give +you another argument. + +It's, again, something you +have heard in the course. + +But you should really +take it seriously, + +and apply to that situation. + +And that's the following. + +Remember when we talked +about the AC stark effect. + +I told you that +you should really + +think about the atom as +a harmonic oscillator. + +We even introduced for you +the oscillator strengths + +that we could even +quantitatively describe + +the response of the atom +to the scattering of light + +by pretty much a model where we +have a mechanical model where + +an electron is attached +with a spring to an origin. + +OK. + +Let me now paraphrase +the question. + +Well, I've given you the answer. + +Before giving you +the answer, I should + +have asked you the +following-- if you now + +make the assumption that you +have a harmonic oscillator, + +the harmonic oscillator has a +resonance frequency of omega 0. + +And it has a damping +rate of gamma. + +But we are driving the harmonic +oscillator not at omega 0; + +we were driving it at +a frequency omega l. + +At what frequency does the +harmonic oscillator respond? + +At the drive frequency +or at its own frequency? + +AUDIENCE: Drive. + +PROFESSOR: Of course. + +It's a drive frequency. + +And if you have a CW experiment, +I said let's wait a second, + +let's really do a +long experiment, + +if you have a driven +harmonic oscillator, + +and you drive it +for a long time, + +and you analyze the +spectrum of the motion, + +is the frequency spectrum of +the driven harmonic oscillator + +absolutely sharp at +the drive frequency? + +Or is it broadened by +gamma, the damping constant + +of the harmonic oscillator? + +AUDIENCE: Sharp. + +PROFESSOR: Who +thinks it's sharp? + +Who thinks it's broad? + +Hands up for sharp. + +Hands up for broad. + +OK. + +AUDIENCE: [INAUDIBLE]. + +PROFESSOR: Look, what you are +overlooking is the following. + +There is the difference +between a transient, which + +is damped out at a rate gamma. + +But then there is +the CW response. + +If you have an ultra-weak drive, +you leave it on for an hour, + +the harmonic oscillator +will reach steady state. + +And it will just oscillate +driven by your drive. + +And it's actually monochromatic. + +And if you analyze +the motion, it's + +a harmonic oscillator in +steady state with a drive, + +and it just moves with a fixed +amplitude and fixed frequency. + +I mean, the way how +I shake my hands, + +this is a delta function +at the drive frequency. + +So in this simple +harmonic oscillator model, + +gamma and damping +comes in when you + +do what I discussed +earlier, when + +you change the drive frequency. + +But this is a completely +different experiment. + +We are not changing +the drive frequency + +and looking for the response. + +We are a fixed drive +frequency, and we + +are analyzing what the +motion is which comes out. + +And then, as you know from +differential equation, + +you may have a grade transient. + +You may have a transient +at the resonance frequency + +which dies out +with a rate gamma. + +This is when you suddenly +switch on your drive, + +and you're not adiabatically +switching on your drive. + +But this is just a transient. + +But what we are asking here +when you do a CW experiment, + +you drive it for a long +time, you look what happens. + +And the motion of the +driven harmonic oscillator + +is a delta function +at the drive. + +And what is valid for +a harmonic oscillator + +is also valid for +the atom, pretty much + +for the same reasons. + +Any questions? + +Yes. + +AUDIENCE: Regarding the +energy conservation in D, + +wouldn't the photon processes +explain energy conservation? + +PROFESSOR: OK. + +You are now really +asking-- Nancy + +is asking about +two-photon processes. + +Well, we don't +want to stop here. + +We want to see something +more interesting. + +This is just sort of the +trivial, simple harmonic + +oscillator. + +The question is now, if you +want to see something richer, + +if we want to see a +little bit of broadening, + +or we want to see something +which is not as boring as just + +a classical harmonic oscillator, +what do we have to do? + +AUDIENCE: Increase the strength. + +PROFESSOR: Increase the +strengths of the field. + +And I heard somebody +saying, two photons. + +And that may be-- + +AUDIENCE: Next-order +perturbation theory. + +PROFESSOR: Pardon? + +AUDIENCE: It's like next +order perturbation theory. + +PROFESSOR: Next-order +perturbation theory. + +But just in the sort +of intuitive picture, + +if you have two photons +which come quickly enough-- + +and how quickly the two +photons come will be debated. + +Of course, it's parametrized +by the Rabi frequency, + +the strengths of the drive. + +But if two photons come +quickly, each photon + +has to be scattered with +a delta function because + +of energy conservation. + +But if we have two +photons, suddenly, it's + +possible that one is scattered +here and one is scattered here. + +And we still conserve energy. + +So if you want to see some form +of line broadening, if you want + +to see all the things +you have mentioned, + +we have to go away from +the low power limit. + +And this is what we do next. + +So we assume that we +have higher power. + +We are on resonance. + +And let me assume that the Rabi +frequency is larger than gamma. + +So what is the physics now +of the atom if the Rabi + +frequency is larger than gamma? + +It can do Rabi oscillation +before it's damped. + +So now we have a +system which has + +an internal dynamics +at the Rabi frequency. + +And you know if you +have an emitter, + +if you have an antenna +which emits light, + +and you move the antenna +around at a frequency-- + +we had the example of a trapped +particle which has a trapped + +frequency of omega +trap-- the spectrum, + +if you Fourier transform, it +leads to the basal function, + +it leads to the sideband. + +So therefore, we know now, +based on all the analogies, + +if you have a modulated +emitter, we obtain sidebands. + +That's what we would +expect classically. + +So let me now ask you the +three following possibilities. + +Maybe we still get +a delta function. + +Maybe we get three peaks where +the splitting is the Rabi + +frequency. + +So the two outer +peaks have a-- and the + +third option is that yes, we +observe the Rabi frequency, + +but the Rabi frequency +is the splitting + +between the outer peaks. + +So the first and second +answer differ by a factor of 2 + +in the sideband spacing. + +So we have three choices. + +Do we expect sidebands? + +That's A and B. Or would +you expect that we still + +have a delta function, +because, well, maybe energy has + +to be conserved at the +single photon level? + +And then is the splitting +Rabi frequency on each side, + +or Rabi frequency between +the two sidebands? + +All right. + +Yes. + +It's indeed the situation. + +For those who picked +A, it's pretty much + +the definition of what +the Rabi frequency is. + +After one cycle of +the Rabi frequency, + +the atom has gone +from the ground state + +to the excited state and +back to the ground state. + +So the model you should have is +that you have an object which + +is emitting light, +but the object + +has some internal modulation +at the Rabi frequency. + +Whatever factor of 2 +you had in the amplitude + +versus probability or +something, all this + +has been factored into +the definition of the Rabi + +frequency in such a way +the atom is really blinking + +between ground and excited +state with a frequency + +which is the Rabi frequency. + +And this frequency +leads-- and the spectrum + +is now the sum and difference +of the relevant frequencies. + +And the relevant frequency +is the resonance frequency + +and the Rabi frequency. + +So the answer is B. + +But this was sort of more +in form of a stick diagram. + +Now I want to bring in +in the next question + +the line broadening. + +So the question is-- and +there are again four choices. + +The question is, we have +now our three sticks. + +One is a carrier, and these +are the two sidebands split off + +by a Rabi frequency. + +Are all three sticks now +sharp delta functions? + +Are all three sticks broadened +by the natural line widths? + +Is the central part +sharp, and only the + +sidebands are broadened? + +Or do we have a sharp +stick with a pedestal, + +and then two sidebands? + +I'm not actually expecting +all of you to know the answer, + +because this is +really now getting + +into more subtle things. + +But just in terms +of show-and-tell, + +and attract your curiosity +to the second part + +of the course, what +would you expect? + +OK. + +Yes. + +Good. + +A is definitely eliminated. + +I mean, if we scatter two +photons simultaneously, there + +will be sort of +broadening of gamma, + +because the atom has +a natural broadening. + +So we can't expect that the +two photon processes are sharp. + +There's no reason +to expect that. + +The answer between B, +C, and D depends now. + +If we have very, very little +power, what we observe + +is, of course, the +low-power delta function. + +And then we observe very, +very small sidebands + +which are broadened. + +So answer C is correct. + +If you just think +about it-- what + +is the structure of +infinitesimal peaks? + +But when you crank up the +power, and what you have is + +you have an elastic +scattering peak, + +which has a delta function, +energy conservation + +at the single photon level. + +And then you have those-- they +are called inelastic peaks. + +But when you crank up the +power, then the central feature + +has also an inelastic component. + +You can sort of argue +that in Rabi oscillation, + +you are in the ground state, +excited state, ground state, + +excited state. + +But if you do now light +scattering in the excited + +state, you +automatically broaden it + +by the lifetime of +the excited state. + +And if you crank up the +power higher and higher, + +the elastic peak will be +more and more suppressed. + +And you find actually +a spectrum which + +has only three broadened +peaks, and the delta function + +has disappeared. + +It will actually be something +where we need more knowledge. + +The broadening of those +peaks is not gamma anymore. + +One of them will be 3/2 +gamma, the other one + +will be 1/2 gamma. + +But this now really requires +a deeper understanding + +in terms of the atom picture. + +But the scale of +all the broadening + +is a factor on the order +of unity times gamma. + +Any questions? + +So the general answer, sorry, +would be-- the generic picture + +which you should keep +in your mind is that. + +You have inelastic scattering +on all three peaks. + +But the limit of D at +very low power is that. + +And at very high power, is that. + +The elastic component +of the central peak + +is either 100% or 0%. + +OK. + +So our last topic for line +shapes and line broadening + +is pressure broadening. + +And as I mentioned +in the introduction, + +pressure broadening has +made modern appearances + +in the form of clock shift, +and mean field shifts, + +and mean field broadenings +in Bose-Einstein condensates. + +But let me sort of +tell you how you + +should understand +pressure broadening. + +I'm using here the +semi-classical picture + +that an excited atom +acts as an oscillator. + +And what happened is the atom-- +you can say the oscillation + +is superposition of +ground and excited state. + +It oscillates. + +But after some time tau, there +may be a quenching collision, + +a de-excitation collision. + +Then the atom is sort +of in the ground state. + +And then it waits until it's +excited again by the laser, + +and the atomic dipole +is oscillating again. + +In a situation like +this, you would + +expect that the total +line widths is actually + +the sum of two rates. + +One is the spontaneous +emission rate, + +and the other one would be the +collision rate, which is this. + +And in general, this is sort +of how people looked at it. + +You vary the pressure +in your buffer gas cell, + +and you find that the line +width has a component which + +increases linearly +with pressure. + +So this is one model +how you can imagine + +what happens in a collision. + +These are like +knock-out collisions. + +When an atom collides, +the excitation, the energy + +disappears. + +The atom is quenched +to the ground state. + +Well, we can draw +up another model, + +where we have an oscillation +of our atomic oscillator. + +But then after +the same time tau, + +there is now a +hiccup in the phase. + +It collides with another atom. + +The other atom is +not de-exciting. + +It's not removing the energy. + +But after the +collision, the atom + +continues to oscillate, but with +a very, very different phase. + +And sort of what I assumed +here is this time where + +the collision happens +is very short. + +It's a very short +collision time. + +That I can approximate +the collisions + +as simply imparting random +phase jumps to the atom. + +Well, if you ask, +what is the widths + +of the spectroscopic line, +it's exactly the same result. + +It just means we have +a different rate. + +It's now a de-phasing +rate, which is 1 over tau. + +And this is added to the +spectroscopic widths. + +OK. + +This is sort of just creating +some phenomenological picture. + +Let's now ask a little +bit more microscopically. + +How can it happen? + +How can it happen that there +is a phase change, that there's + +a change in the phase of +the atomic oscillator? + +And this leads us now to +consider the interaction + +potential as a function +of r between two atoms. + +We have one atom which is +sort of our active atom, which + +has an excited and ground state. + +And this atom is now +getting closer to, + +let's say, an argon atom, +which acts as buffer gas. + +And what I'm plotting +in this graph now + +is the interaction potential +between our light-emitting, + +or light-absorbing, atoms +and the buffer gas atom. + +And let's just +genetically assume there + +is sort of something like +a molecular potential. + +But in general, the +molecular potentials + +will be different in the +ground and excited state. + +And of course, if you +do hyperfine transitions + +between atoms in a +Bose-Einstein condensate, + +you may have a +scattering length, + +which is different +in the two states. + +And I think you +see the connection. + +So in general, if the +interaction environment + +is different between +ground and excited state, + +we expect that the +interaction potential + +causes certain shifts. + +So we could use the picture +that we have a phase evolution. + +And the phase evolution +is a frequency difference + +which is simply given by +the difference of the two + +potentials. + +So the picture is a little +bit-- which is actually + +very valid for cold +collisions, which-- well, + +really a new chapter +in atomic physics + +opened up by laser cooling +and magneto-optic traps. + +An atom, when it emits a +photon, would emit here + +at the resonance frequency. + +But if the collision +is very, very slow, + +it will actually emit, +with a certain probability, + +a photon which is shifted +by exactly this expression. + +And in that limit, that +could be very interesting, + +because by analyzing +the spectrum + +of the immediate light, +you learn something + +about the interaction +potential of two atoms. + +But of course, this argument +has a little bit of a flaw, + +because you can observe a +frequency not instantaneously. + +You can observe-- if a +collision happens very fast, + +you would actually go through +those frequency changes so fast + +that you cannot resolve them. + +The question is, +which one is larger? + +So if the frequency +shift is larger + +than the inverse time for the +duration of the collision, + +then you can observe it. + +Otherwise, you can't. + +So the picture we should +draw is now the following. + +And this is sort of +a microscopic picture + +on those phase jumps, +which I mentioned earlier. + +That you have your +atomic oscillator. + +The atom is oscillating. + +But now it comes +close to another atom. + +And let's assume there +is an energy increase + +between ground and excited +state due to the presence + +of the buffer gas atom. + +Then you would say you +get a quick oscillation. + +Depending on the +impact parameter, + +it can last various +amount of time. + +And then later, the +oscillation starts. + +But essentially, this +causes a random phase jump. + +So this time here is the +collision time tau c. + +What we expect now is we +have to now interpolate + +between two models. + +I'm not taking it any +further than that. + +We have an interesting +line shape. + +There may be a central part +which is simply collisionally + +broadened by the +interruptions of the phase, + +by the number of collisions +with the collision time tau. + +But if when the atoms collide, +there is a huge frequency shift + +momentarily, that this will +actually affect the wings. + +So for frequency shifts which +come from the interaction + +potential which are much +larger than the collision time, + +than the time +between collisions, + +we will observe +something which goes + +by the name "far +wing broadening." + +And also, the central part +of the potential is simply, + +you can say, it's a +Lorentzian which is simply + +broadened by the collision rate. + +There is no microscopic +information-- + +what is the nature, +what is going on + +during the phase jumps. + +The wings will have +actually information + +about the molecular potential. + +And I just wanted to present +it to you in this way + +to sort of show how you +actually have, in a line shape, + +often two effects. + +One is pretty much +just the interruption + +of the coherence which +gives the central line. + +But you still have, at +least in some limit, + +information about what +causes those phase jumps. + +And this appears in the wings. + +20 years ago in the +atomic physics course, + +we taught you a theory +how to describe that. + +It could be probably +taught in one hour. + +There are some +links on the Wiki, + +but I don't want to +carry that further. + +Any questions about that? + +AUDIENCE: So why has the +importance decreased? + +PROFESSOR: The +importance has decreased + +of that, because +I mean, who of you + +is studying atoms and gas cells? + +Nobody. + +The frontier has moved on. + +We are much more in a +regime where we are not + +observing atoms in +certain environment. + +We are creating an interesting +system out of atoms + +by putting the atoms in a +well-defined environment where + +those things are absent. + +Or in the ultra-cold +domain, and de Broglie + +wavelengths is so long that this +kind of model for collisions + +is no longer applicable. + +We are in the extreme case of +a single partial wave, where + +a single parameter, +the scattering lengths, + +describes all of it. + +OK. + +Cory? + +AUDIENCE: Yeah. + +Could you talk for a +little bit about how + +this model of collisions +breaks down and allows + +for Dicke narrowing? + +PROFESSOR: Yes. + +Thank you. + +That was one comment I forgot. + +What happens is you have Dicke-- +thanks for this question. + +You have Dicke-- I drew up +the two potential curves. + +If the two potential curves +are absolutely identical, + +the atoms can approach +each other and can collide. + +But there is never +any perturbation + +to the atomic oscillator, +because the frequency + +between ground and +excited state is omega 0, + +no matter whether the atom +undergoes a collision or not. + +In this limit, which is +often realized in collisions + +with rare gases, +in this limit, you + +do not have any phase +interruption by the collision. + +And this is the prerequisite +for Dicke narrowing. + +OK. + +I think we have the +full picture now. + +And that means we can move +on to two-photon excitations. + +So whenever you +start a new chapter, + +you should motivate it. + +And the question is, why +should you be interested? + +Well, I can also turn it +around and said, why not? + +Because those things happen. + +And if those things happen, +we want to learn about them. + +And they actually +happen very naturally. + +The moment you go to +higher laser power + +and you go beyond the lowest +order of perturbation theory, + +you may actually excite two +photons at the same time. + +And actually, what we just +discussed about the emission + +spectrum of an atom, with the +sidebands, with the broadening, + +these are actually +examples where we really + +have to think about it in +a two-photon picture, not + +a single-photon picture. + +The second motivation +is very practical. + +We may want to excite an +atom from a low-lying level + +to a high-lying level. + +But the only laser we can +buy, or the only laser we have + +in the laboratory +has lower frequency. + +That doesn't mean +that the case is + +lost by just stacking two +photons on top of each other. + +We can bridge the +gap and still excite + +the atom, which has +transitions only far in the UV. + +And all we have is +these visible lasers. + +There's another +thing which changes. + +Maybe we want to excite hydrogen +from the 1s to the 2s level. + +1s and 2s have the same parity. + +And if we try to excite +it with one photon, + +because of the dipole +operator which has odd parity, + +this is not allowed. + +So there are maybe +selection rules + +where we can go to +desirable final state + +only with two photons +and not with one photon. + +Finally, I will show you +on Wednesday-- remember, + +there is no class on Monday, +because the whole CUA + +will go crazy with the NSF +site visit on Monday, Tuesday. + +So the next class on Wednesday. + +And on Wednesday, +I will actually + +show you if the two photons come +from counter-propagating beams, + +the net momentum transfer +to the atom is 0. + +And net momentum transfer of +0 means zero Doppler shift. + +So two photons give +us an opportunity, + +which doesn't exist +with the single photon. + +We can excite the atom +without transferring momentum. + +And this is the basis of a +Doppler free spectroscopy + +technique. + +And finally, for purely +conceptional reasons, + +we've talked so much about +excitation of an atom, + +and then ask, what is the +rate of light scattering? + +So we have actually used +two-photon processes + +in the course many, many +times without actually + +adequately addressing them. + +I didn't tell you +anything wrong. + +I was sort of choosing +my words carefully, + +that everything I told you about +light emission and absorption + +is comparable with +the correct picture. + +And the correct picture +is if a photon goes in + +and a photon goes out, +you have to describe it + +as one process +involving two photons. + +So I think we have +enough reasons why + +we should be interested. + +And if I take this picture, +that I start in one state + +and have a two-photon +absorption process, + +I actually want to +redraw it, because + +in the dipole approximation, +which I want to use here, + +we have the dipole operator, +and second quantization + +is a plus a dagger. + +The electric field +is a plus a dagger. + +So each application +of the operator + +takes us from one state to +the next with a single photon. + +So therefore, if you +talk about two photons, + +we can only absorb +them if we have + +an intermediate state, +which I will call f. + +So we should really think +about two-photon absorption + +as a two-step process which +involves an intermediate state. + +And it has to be +like that if we want + +to use, as the +operator for atom light + +interaction, the +dipole operator, + +because a dipole +operator is creating + +and-- the dipole operator +involves electric field. + +And that creates or annihilates +one photon at a time. + +Let me just make a +side remark, but this + +will be addressed in 8.422. + +If you use the description +of the interaction + +with the electromagnetic +field, which + +is the p minus e Hamiltonian, +and you square it, + +if you square that, you +get an A squared term. + +The A squared term is +actually the product + +of a plus a dagger squared. + +So you can actually, +with the A squared term, + +scatter two photons by going +from one state to another one. + +But I'm not discussing it here. + +And I leave a detailed +comparison and discussion + +of that to 8.422. + +Now we are strictly adhering +to the dipole approximation. + +Oh, actually, let me +make a comment about it, + +because I just realized if I +say something and don't say it + +fully, I may confuse people. + +So what I want to say is, +we will show, in 8.422 + +that the two pictures, the +pap minus a Hamiltonian + +and the dipole Hamiltonian +are equivalent. + +They're connected by +canonical transformation. + +So therefore, it is not a +fundamental aspect of nature, + +whether you can scatter +only one photon when + +you go from one +state to the other. + +There are two +equivalent descriptions. + +In one description, you +sometimes scatter two photons. + +In the other description, +you scatter only one photon. + +And you will all +get a PSET in 8.422 + +where you show for one +example that the results are + +the same when you sum up +over all possibilities. + +So therefore, I can +maybe here should rather + +take the position, the generic +description of light scattering + +uses the dipole approximation. + +And in the dipole +approximation, we + +are describing the +atoms, that they only + +exchange one photon when they +go from one state to the next. + +And this is a full description +but not the only description. + +So therefore, we need +an intermediate state. + +But assuming that the +first laser is not + +resonant with the transition +to the intermediate state, + +we need this dashed line. + +This dashed line is sometimes +called a virtual state. + +And in the following +discussion, we + +will really learn what is the +nature of the virtual state + +and what does it mean. + +But we need a stepping stone +for a two-photon process + +in the form of +intermediate states. + +So maybe I should +just use three minutes + +and show you how you +would calculate it. + +I use pre-written +slides here, because I'm + +getting a little bit +bored of just writing down + +the same or similar +perturbative expressions. + +And I just step you through. + +So I said we use +the dipole operator. + +But now-- and this +is a new thing-- + +the electric field +has not only one + +component and one frequency. + +We want to look at two +photons, so therefore, it + +has two frequencies. + +So therefore, our +perturbation Hamiltonian + +is what we had so far +for monochromatic field. + +But then we have +an additional term + +where we just change the +index from one to two + +to have the second +laser field described. + +So let me now introduce +matrix elements. + +We have to go from state a +to some intermediate state. + +And then we go to state b. + +So therefore, we +need matrix elements + +which take us from +state a to state f. + +And again, we have two +such possibilities-- + +one at omega 1, +one at omega 2, one + +driven by field 1, the +other one driven by field 2. + +And yeah, we all have +the counter-rotating and + +co-rotating terms. + +What happens is we have, of +course, a complex conjugate. + +But I told you +already several times + +that there is an e +to the minus i omega + +1, which is responsible +for absorption. + +The plus i omega +1 does emission. + +And let me just-- I want +to do the rotating wave + +approximation, only +keep the relevant term. + +So I look at +two-photon absorption. + +And that means I only keep +forward the minus terms. + +You could, if you +want, duplicate + +the lengths of each +formula and carry forward + +the counter-rotating term. + +You're not learning +anything new. + +You get additional +Bloch-Siegerts + +and AC stark shifts. + +This is not the new feature +I want to implement. + +So let's focus on +the new aspect. + +And this is the following. + +We do first-order +perturbation theory, + +which takes us in the first +step to the intermediate state. + +And you have seen this +expression many, many times. + +The only thing is in addition to +what we had for one laser beam, + +we have to add a second +possibility, which + +comes from the second field. + +And now we are at the +intermediate step. + +And we want to take the second +step to the final state. + +So what we are now doing is we +are writing down Schrodinger's + +equation, derivative +of the wave function + +is Hamiltonian times +the wave function. + +And we are especially +interested in how + +do we accumulate probability or +amplitude in the final state. + +But what we are doing is +on the right-hand side, + +because we can't start +in the ground state, + +we've gone to the +intermediate state, + +we are now plugging in +the previous result, + +the first-order result for +the intermediate state. + +So therefore, by using +second-order perturbation + +theory, we want the second-order +perturbation theory, + +so we integrate this equation +with respect to time. + +But on the right side, we +use our first-order result, + +which we had derived earlier. + +And then we just write +down the integral. + +Everything is just +exponential function. + +And we get the result here. + +So now with two steps, we +have obtained an expression + +for-- I know time +is over, but let + +me just finish the argument. + +So we have now an expression +in second-order perturbation + +theory. + +What is the amplitude +in the final state? + +And things look a +little bit messy, + +because we have four terms. + +And we should get +four terms, because we + +have two interactions. + +We can take one +photon of one laser + +beam-- first step, omega +1; second step, omega two. + +We can switch the +order of photons. + +And of course, if you write +down everything correctly, + +nothing is forbidding the atom +of taking both photons out + +of the same laser beam. + +Yeah, let me stop here. \ No newline at end of file diff --git a/FvwDJ3Op2Js.txt b/FvwDJ3Op2Js.txt new file mode 100644 index 0000000000000000000000000000000000000000..5e55094acdd7d1470b2b734a89398f5385e3ada0 --- /dev/null +++ b/FvwDJ3Op2Js.txt @@ -0,0 +1,14459 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +view additional materials from hundreds + + align:start position:0% +view additional materials from hundreds + + + align:start position:0% +view additional materials from hundreds +of MIT courses visit mitop courseware at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu how's everybody + + align:start position:0% +ocw.mit.edu how's everybody + + + align:start position:0% +ocw.mit.edu how's everybody +doing good yeah + + align:start position:0% +doing good yeah + + + align:start position:0% +doing good yeah +I wanted to start with some + + align:start position:0% +I wanted to start with some + + + align:start position:0% +I wanted to start with some +inspiration um and uh so because I love + + align:start position:0% +inspiration um and uh so because I love + + + align:start position:0% +inspiration um and uh so because I love +uh + + align:start position:0% +uh + + + align:start position:0% +uh +videos and I think that's a way of + + align:start position:0% +videos and I think that's a way of + + + align:start position:0% +videos and I think that's a way of +inspiring and sometimes I think if you + + align:start position:0% +inspiring and sometimes I think if you + + + align:start position:0% +inspiring and sometimes I think if you +feel really passionate about something + + align:start position:0% +feel really passionate about something + + + align:start position:0% +feel really passionate about something +you can use uh song and video as a way + + align:start position:0% +you can use uh song and video as a way + + + align:start position:0% +you can use uh song and video as a way +of conveying your ideas I have a good + + align:start position:0% +of conveying your ideas I have a good + + + align:start position:0% +of conveying your ideas I have a good +friend actually who's been doing that um + + align:start position:0% +friend actually who's been doing that um + + + align:start position:0% +friend actually who's been doing that um +so I want to show you anybody heard to + + align:start position:0% +so I want to show you anybody heard to + + + align:start position:0% +so I want to show you anybody heard to +fog and + + align:start position:0% +fog and + + + align:start position:0% +fog and +smog okay I'm going to show you this + + align:start position:0% +smog okay I'm going to show you this + + + align:start position:0% +smog okay I'm going to show you this +little + + align:start position:0% +little + + + align:start position:0% +little +video + + align:start position:0% +video + + + align:start position:0% +video +um just a minute or just a minute of + + align:start position:0% +um just a minute or just a minute of + + + align:start position:0% +um just a minute or just a minute of +it I mean you know what's crazy to me is + + align:start position:0% +it I mean you know what's crazy to me is + + + align:start position:0% +it I mean you know what's crazy to me is +like nobody ever talks in person anymore + + align:start position:0% +like nobody ever talks in person anymore + + + align:start position:0% +like nobody ever talks in person anymore +you know like you got Twitter Facebook + + align:start position:0% +you know like you got Twitter Facebook + + + align:start position:0% +you know like you got Twitter Facebook +and everybody's sending text messages + + align:start position:0% +and everybody's sending text messages + + + align:start position:0% +and everybody's sending text messages +but like nobody's ever sitting down like + + align:start position:0% +but like nobody's ever sitting down like + + + align:start position:0% +but like nobody's ever sitting down like +this and just talking you know I mean + + align:start position:0% +this and just talking you know I mean + + + align:start position:0% +this and just talking you know I mean +for all these Technologies we're + + align:start position:0% +for all these Technologies we're + + + align:start position:0% +for all these Technologies we're +actually further apart you know what I'm + + align:start position:0% +actually further apart you know what I'm + + + align:start position:0% +actually further apart you know what I'm +saying hello + + align:start position:0% +saying hello + + + align:start position:0% +saying hello +it's my good friend DJ + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +Dave my favorite Cafe trying to get my + + align:start position:0% +Dave my favorite Cafe trying to get my + + + align:start position:0% +Dave my favorite Cafe trying to get my +coffee like I do every single day this + + align:start position:0% +coffee like I do every single day this + + + align:start position:0% +coffee like I do every single day this +dude of + + align:start position:0% + + + + align:start position:0% + +aamn + + align:start position:0% + + + + align:start position:0% + +of L he to the counter like um I'm like + + align:start position:0% +of L he to the counter like um I'm like + + + align:start position:0% +of L he to the counter like um I'm like +man you're hell + + align:start position:0% + + + + align:start position:0% + +dumb all right so I won show the whole + + align:start position:0% +dumb all right so I won show the whole + + + align:start position:0% +dumb all right so I won show the whole +thing that's actually a good family + + align:start position:0% +thing that's actually a good family + + + align:start position:0% +thing that's actually a good family +friend DJ Dave he I I lived in his room + + align:start position:0% +friend DJ Dave he I I lived in his room + + + align:start position:0% +friend DJ Dave he I I lived in his room +for a year awesome guy um uh and uh uh + + align:start position:0% +for a year awesome guy um uh and uh uh + + + align:start position:0% +for a year awesome guy um uh and uh uh +he's made some some really nice videos + + align:start position:0% +he's made some some really nice videos + + + align:start position:0% +he's made some some really nice videos +the point is this is not quantum + + align:start position:0% +the point is this is not quantum + + + align:start position:0% +the point is this is not quantum +mechanics related um it is a topic near + + align:start position:0% +mechanics related um it is a topic near + + + align:start position:0% +mechanics related um it is a topic near +and dear to my heart as some of you know + + align:start position:0% +and dear to my heart as some of you know + + + align:start position:0% +and dear to my heart as some of you know +um and I'm sure you're all closing your + + align:start position:0% +um and I'm sure you're all closing your + + + align:start position:0% +um and I'm sure you're all closing your +laptops and putting your phones down um + + align:start position:0% +laptops and putting your phones down um + + + align:start position:0% +laptops and putting your phones down um +especially after seeing that um but the + + align:start position:0% +especially after seeing that um but the + + + align:start position:0% +especially after seeing that um but the +point is he's passionate so what does he + + align:start position:0% +point is he's passionate so what does he + + + align:start position:0% +point is he's passionate so what does he +do he conveys his passion in song now if + + align:start position:0% +do he conveys his passion in song now if + + + align:start position:0% +do he conveys his passion in song now if +any of you some of you so this is + + align:start position:0% +any of you some of you so this is + + + align:start position:0% +any of you some of you so this is +related to the class if any of you have + + align:start position:0% +related to the class if any of you have + + + align:start position:0% +related to the class if any of you have +an idea that you're passionate about + + align:start position:0% +an idea that you're passionate about + + + align:start position:0% +an idea that you're passionate about +like say for your final project and you + + align:start position:0% +like say for your final project and you + + + align:start position:0% +like say for your final project and you +You' like to do something like that I + + align:start position:0% +You' like to do something like that I + + + align:start position:0% +You' like to do something like that I +would really um be fully supportive I + + align:start position:0% +would really um be fully supportive I + + + align:start position:0% +would really um be fully supportive I +tried to um some of you may remember my + + align:start position:0% +tried to um some of you may remember my + + + align:start position:0% +tried to um some of you may remember my +attempts to get you to do that in uh + + align:start position:0% +attempts to get you to do that in uh + + + align:start position:0% +attempts to get you to do that in uh +3012 and now guess how many people + + align:start position:0% +3012 and now guess how many people + + + align:start position:0% +3012 and now guess how many people +actually did that in + + align:start position:0% +actually did that in + + + align:start position:0% +actually did that in +3012 right not so many but if somebody + + align:start position:0% +3012 right not so many but if somebody + + + align:start position:0% +3012 right not so many but if somebody +wants to somebody wants to take a crack + + align:start position:0% +wants to somebody wants to take a crack + + + align:start position:0% +wants to somebody wants to take a crack +at you know conveying their project in + + align:start position:0% +at you know conveying their project in + + + align:start position:0% +at you know conveying their project in +uh you know in this format + + align:start position:0% +uh you know in this format + + + align:start position:0% +uh you know in this format +um is there's got to be a bonus point or + + align:start position:0% +um is there's got to be a bonus point or + + + align:start position:0% +um is there's got to be a bonus point or +two in that just alone right um and how + + align:start position:0% +two in that just alone right um and how + + + align:start position:0% +two in that just alone right um and how +many of you are any of you Juniors + + align:start position:0% +many of you are any of you Juniors + + + align:start position:0% +many of you are any of you Juniors +Junior lab are you doing that in vanet's + + align:start position:0% +Junior lab are you doing that in vanet's + + + align:start position:0% +Junior lab are you doing that in vanet's +class yeah so I saw some of those and + + align:start position:0% +class yeah so I saw some of those and + + + align:start position:0% +class yeah so I saw some of those and +I'm like man I I you know it made me I + + align:start position:0% +I'm like man I I you know it made me I + + + align:start position:0% +I'm like man I I you know it made me I +want that you know I think that's I + + align:start position:0% +want that you know I think that's I + + + align:start position:0% +want that you know I think that's I +think that's really creative and cool so + + align:start position:0% +think that's really creative and cool so + + + align:start position:0% +think that's really creative and cool so +I I see a lot of really cool stuff I saw + + align:start position:0% +I I see a lot of really cool stuff I saw + + + align:start position:0% +I I see a lot of really cool stuff I saw +a couple of those they were really great + + align:start position:0% +a couple of those they were really great + + + align:start position:0% +a couple of those they were really great +so if anybody wants um um uh to do that + + align:start position:0% +so if anybody wants um um uh to do that + + + align:start position:0% +so if anybody wants um um uh to do that +let me know and i' I'd be happy to + + align:start position:0% +let me know and i' I'd be happy to + + + align:start position:0% +let me know and i' I'd be happy to +support however I can put you in touch + + align:start position:0% +support however I can put you in touch + + + align:start position:0% +support however I can put you in touch +with CJ Dave if you want um or whatever + + align:start position:0% +with CJ Dave if you want um or whatever + + + align:start position:0% +with CJ Dave if you want um or whatever +okay all right any questions about uh + + align:start position:0% +okay all right any questions about uh + + + align:start position:0% +okay all right any questions about uh +class project so so you know I've been + + align:start position:0% +class project so so you know I've been + + + align:start position:0% +class project so so you know I've been +talking to some of you about the + + align:start position:0% +talking to some of you about the + + + align:start position:0% +talking to some of you about the +projects um and uh um if anyone is still + + align:start position:0% +projects um and uh um if anyone is still + + + align:start position:0% +projects um and uh um if anyone is still +interested it's not too late um but + + align:start position:0% +interested it's not too late um but + + + align:start position:0% +interested it's not too late um but +we're getting close to being too late so + + align:start position:0% +we're getting close to being too late so + + + align:start position:0% +we're getting close to being too late so +please come talk to me if you still want + + align:start position:0% +please come talk to me if you still want + + + align:start position:0% +please come talk to me if you still want +to do a project this would be like the + + align:start position:0% +to do a project this would be like the + + + align:start position:0% +to do a project this would be like the +last week I think to um get something + + align:start position:0% +last week I think to um get something + + + align:start position:0% +last week I think to um get something +going + + align:start position:0% +going + + + align:start position:0% +going +um what I want to do today is well + + align:start position:0% +um what I want to do today is well + + + align:start position:0% +um what I want to do today is well +before I start um here's where we are + + align:start position:0% +before I start um here's where we are + + + align:start position:0% +before I start um here's where we are +okay so what I want to do is is continue + + align:start position:0% +okay so what I want to do is is continue + + + align:start position:0% +okay so what I want to do is is continue +on our March we talked about atoms to + + align:start position:0% +on our March we talked about atoms to + + + align:start position:0% +on our March we talked about atoms to +solids laid a little the groundwork + + align:start position:0% +solids laid a little the groundwork + + + align:start position:0% +solids laid a little the groundwork +we'll review some of that and then go on + + align:start position:0% +we'll review some of that and then go on + + + align:start position:0% +we'll review some of that and then go on +to um um you know sort of some of the + + align:start position:0% +to um um you know sort of some of the + + + align:start position:0% +to um um you know sort of some of the +things you can do uh once you model + + align:start position:0% +things you can do uh once you model + + + align:start position:0% +things you can do uh once you model +solids and I want to do some + + align:start position:0% +solids and I want to do some + + + align:start position:0% +solids and I want to do some +calculations assuming that it works um + + align:start position:0% +calculations assuming that it works um + + + align:start position:0% +calculations assuming that it works um +uh using the nanohub interactively + + align:start position:0% +uh using the nanohub interactively + + + align:start position:0% +uh using the nanohub interactively +together because again there is nothing + + align:start position:0% +together because again there is nothing + + + align:start position:0% +together because again there is nothing +like calculating um the behavior of + + align:start position:0% +like calculating um the behavior of + + + align:start position:0% +like calculating um the behavior of +electrons with friends there's no better + + align:start position:0% +electrons with friends there's no better + + + align:start position:0% +electrons with friends there's no better +way to you know create good group + + align:start position:0% +way to you know create good group + + + align:start position:0% +way to you know create good group +dynamics and + + align:start position:0% + + + + align:start position:0% + +interactions there's some I mean + + align:start position:0% +interactions there's some I mean + + + align:start position:0% +interactions there's some I mean +Computing uh has kind of the the the + + align:start position:0% +Computing uh has kind of the the the + + + align:start position:0% +Computing uh has kind of the the the +nuts and bolts uh a lot of which we're + + align:start position:0% +nuts and bolts uh a lot of which we're + + + align:start position:0% +nuts and bolts uh a lot of which we're +talking about some of which were not um + + align:start position:0% +talking about some of which were not um + + + align:start position:0% +talking about some of which were not um +and and then it has sort of the + + align:start position:0% +and and then it has sort of the + + + align:start position:0% +and and then it has sort of the +philosophy right and you know I I really + + align:start position:0% +philosophy right and you know I I really + + + align:start position:0% +philosophy right and you know I I really +tend to agree with some of the things + + align:start position:0% +tend to agree with some of the things + + + align:start position:0% +tend to agree with some of the things +that um people have said + + align:start position:0% +that um people have said + + + align:start position:0% +that um people have said +over the years on on how to use + + align:start position:0% +over the years on on how to use + + + align:start position:0% +over the years on on how to use +Computing um and so I just want to bring + + align:start position:0% +Computing um and so I just want to bring + + + align:start position:0% +Computing um and so I just want to bring +this in and I'll come back to this sort + + align:start position:0% +this in and I'll come back to this sort + + + align:start position:0% +this in and I'll come back to this sort +of at the end of of the term a little + + align:start position:0% +of at the end of of the term a little + + + align:start position:0% +of at the end of of the term a little +bit more but you know Richard Hamming + + align:start position:0% +bit more but you know Richard Hamming + + + align:start position:0% +bit more but you know Richard Hamming +had a number of very interesting things + + align:start position:0% +had a number of very interesting things + + + align:start position:0% +had a number of very interesting things +to say about research and and about + + align:start position:0% +to say about research and and about + + + align:start position:0% +to say about research and and about +Computing the P purpose of computing is + + align:start position:0% +Computing the P purpose of computing is + + + align:start position:0% +Computing the P purpose of computing is +Insight not numbers right so you know + + align:start position:0% +Insight not numbers right so you know + + + align:start position:0% +Insight not numbers right so you know +the computation is only as good as your + + align:start position:0% +the computation is only as good as your + + + align:start position:0% +the computation is only as good as your +creativity and your thinking on both + + align:start position:0% +creativity and your thinking on both + + + align:start position:0% +creativity and your thinking on both +sides what you put into the computer and + + align:start position:0% +sides what you put into the computer and + + + align:start position:0% +sides what you put into the computer and +what you get out um he also said um what + + align:start position:0% +what you get out um he also said um what + + + align:start position:0% +what you get out um he also said um what +are the most important problems in your + + align:start position:0% +are the most important problems in your + + + align:start position:0% +are the most important problems in your +field are you working on one of them why + + align:start position:0% +field are you working on one of them why + + + align:start position:0% +field are you working on one of them why +not I love that and that's that's very + + align:start position:0% +not I love that and that's that's very + + + align:start position:0% +not I love that and that's that's very +much you know that's kind of an MIT + + align:start position:0% +much you know that's kind of an MIT + + + align:start position:0% +much you know that's kind of an MIT +ecosystem way right but it's not true + + align:start position:0% +ecosystem way right but it's not true + + + align:start position:0% +ecosystem way right but it's not true +everywhere but we should always remind + + align:start position:0% +everywhere but we should always remind + + + align:start position:0% +everywhere but we should always remind +ourselves even if I solve this problem + + align:start position:0% +ourselves even if I solve this problem + + + align:start position:0% +ourselves even if I solve this problem +so i' say my problem is I want to change + + align:start position:0% +so i' say my problem is I want to change + + + align:start position:0% +so i' say my problem is I want to change +the bandap of silicon from indirect to + + align:start position:0% +the bandap of silicon from indirect to + + + align:start position:0% +the bandap of silicon from indirect to +direct okay I can do that now because + + align:start position:0% +direct okay I can do that now because + + + align:start position:0% +direct okay I can do that now because +we've learned how to do that using + + align:start position:0% +we've learned how to do that using + + + align:start position:0% +we've learned how to do that using +simulation so I can probe materials + + align:start position:0% +simulation so I can probe materials + + + align:start position:0% +simulation so I can probe materials +using a computer you should still say + + align:start position:0% +using a computer you should still say + + + align:start position:0% +using a computer you should still say +why right and that's not the the point + + align:start position:0% +why right and that's not the the point + + + align:start position:0% +why right and that's not the the point +isn't you can't just say why well + + align:start position:0% +isn't you can't just say why well + + + align:start position:0% +isn't you can't just say why well +because it would be useful or why well + + align:start position:0% +because it would be useful or why well + + + align:start position:0% +because it would be useful or why well +because I can make a better solar cell + + align:start position:0% +because I can make a better solar cell + + + align:start position:0% +because I can make a better solar cell +that's not enough right it's really how + + align:start position:0% +that's not enough right it's really how + + + align:start position:0% +that's not enough right it's really how +much impact can you have right what is + + align:start position:0% +much impact can you have right what is + + + align:start position:0% +much impact can you have right what is +this going to do to the technology + + align:start position:0% +this going to do to the technology + + + align:start position:0% +this going to do to the technology +you're working on or the science problem + + align:start position:0% +you're working on or the science problem + + + align:start position:0% +you're working on or the science problem +you're trying to uh answer and taking it + + align:start position:0% +you're trying to uh answer and taking it + + + align:start position:0% +you're trying to uh answer and taking it +those extra steps goes a long way and + + align:start position:0% +those extra steps goes a long way and + + + align:start position:0% +those extra steps goes a long way and +that applies to Computing just like any + + align:start position:0% +that applies to Computing just like any + + + align:start position:0% +that applies to Computing just like any +other area of of research better to + + align:start position:0% +other area of of research better to + + + align:start position:0% +other area of of research better to +solve the right problem the wrong way + + align:start position:0% +solve the right problem the wrong way + + + align:start position:0% +solve the right problem the wrong way +than the wrong problem the right way + + align:start position:0% +than the wrong problem the right way + + + align:start position:0% +than the wrong problem the right way +right so CH choosing the problem that's + + align:start position:0% +right so CH choosing the problem that's + + + align:start position:0% +right so CH choosing the problem that's +a related statement in research if you + + align:start position:0% +a related statement in research if you + + + align:start position:0% +a related statement in research if you +know what you're doing then you + + align:start position:0% +know what you're doing then you + + + align:start position:0% +know what you're doing then you +shouldn't be doing it I like that a lot + + align:start position:0% +shouldn't be doing it I like that a lot + + + align:start position:0% +shouldn't be doing it I like that a lot +right so we you know and and that's + + align:start position:0% +right so we you know and and that's + + + align:start position:0% +right so we you know and and that's +where um computation is is a real + + align:start position:0% +where um computation is is a real + + + align:start position:0% +where um computation is is a real +enabler right I I love I'm mean + + align:start position:0% +enabler right I I love I'm mean + + + align:start position:0% +enabler right I I love I'm mean +experiments too but I love the the the + + align:start position:0% +experiments too but I love the the the + + + align:start position:0% +experiments too but I love the the the +world of computation um especially at + + align:start position:0% +world of computation um especially at + + + align:start position:0% +world of computation um especially at +this scale where you can you can Design + + align:start position:0% +this scale where you can you can Design + + + align:start position:0% +this scale where you can you can Design +Within you know a limited number of + + align:start position:0% +Within you know a limited number of + + + align:start position:0% +Within you know a limited number of +atoms you can design anything you can + + align:start position:0% +atoms you can design anything you can + + + align:start position:0% +atoms you can design anything you can +think up anything and try it right so + + align:start position:0% +think up anything and try it right so + + + align:start position:0% +think up anything and try it right so +there's really um you know the face + + align:start position:0% +there's really um you know the face + + + align:start position:0% +there's really um you know the face +space is just enormous and you can + + align:start position:0% +space is just enormous and you can + + + align:start position:0% +space is just enormous and you can +really play around um and try crazy + + align:start position:0% +really play around um and try crazy + + + align:start position:0% +really play around um and try crazy +ideas um random thoughts and tangents + + align:start position:0% +ideas um random thoughts and tangents + + + align:start position:0% +ideas um random thoughts and tangents +out as you go those are often where the + + align:start position:0% +out as you go those are often where the + + + align:start position:0% +out as you go those are often where the +best uh creativity happens and then this + + align:start position:0% +best uh creativity happens and then this + + + align:start position:0% +best uh creativity happens and then this +is it right machines should work people + + align:start position:0% +is it right machines should work people + + + align:start position:0% +is it right machines should work people +should think + + align:start position:0% +should think + + + align:start position:0% +should think +so you know as you go after this class + + align:start position:0% +so you know as you go after this class + + + align:start position:0% +so you know as you go after this class +you come out you know one of the most + + align:start position:0% +you come out you know one of the most + + + align:start position:0% +you come out you know one of the most +important things to come out of this is + + align:start position:0% +important things to come out of this is + + + align:start position:0% +important things to come out of this is +it's it's always a balance when you do + + align:start position:0% +it's it's always a balance when you do + + + align:start position:0% +it's it's always a balance when you do +computation it's a balance between your + + align:start position:0% +computation it's a balance between your + + + align:start position:0% +computation it's a balance between your +time and the computer's time and what + + align:start position:0% +time and the computer's time and what + + + align:start position:0% +time and the computer's time and what +you'd like to do is create a balance + + align:start position:0% +you'd like to do is create a balance + + + align:start position:0% +you'd like to do is create a balance +such that the computer is solving things + + align:start position:0% +such that the computer is solving things + + + align:start position:0% +such that the computer is solving things +for you um and you're spending most of + + align:start position:0% +for you um and you're spending most of + + + align:start position:0% +for you um and you're spending most of +your time not solving those things not + + align:start position:0% +your time not solving those things not + + + align:start position:0% +your time not solving those things not +wasting your time on things that the + + align:start position:0% +wasting your time on things that the + + + align:start position:0% +wasting your time on things that the +computer could do um but rather on + + align:start position:0% +computer could do um but rather on + + + align:start position:0% +computer could do um but rather on +thinking about the kind of problem that + + align:start position:0% +thinking about the kind of problem that + + + align:start position:0% +thinking about the kind of problem that +you're going to make it do and and you'd + + align:start position:0% +you're going to make it do and and you'd + + + align:start position:0% +you're going to make it do and and you'd +be surprised how often in computation + + align:start position:0% +be surprised how often in computation + + + align:start position:0% +be surprised how often in computation +this balance is not well-kept okay + + align:start position:0% +this balance is not well-kept okay + + + align:start position:0% +this balance is not well-kept okay +and and how often you might spend a lot + + align:start position:0% +and and how often you might spend a lot + + + align:start position:0% +and and how often you might spend a lot +of your time actually um spinning your + + align:start position:0% +of your time actually um spinning your + + + align:start position:0% +of your time actually um spinning your +wheels on something that the machine + + align:start position:0% +wheels on something that the machine + + + align:start position:0% +wheels on something that the machine +could actually handle right um and how + + align:start position:0% +could actually handle right um and how + + + align:start position:0% +could actually handle right um and how +much you might think the machine is + + align:start position:0% +much you might think the machine is + + + align:start position:0% +much you might think the machine is +actually going to somehow solve a + + align:start position:0% +actually going to somehow solve a + + + align:start position:0% +actually going to somehow solve a +problem um that actually you need to + + align:start position:0% +problem um that actually you need to + + + align:start position:0% +problem um that actually you need to +think about to solve or how much more + + align:start position:0% +think about to solve or how much more + + + align:start position:0% +think about to solve or how much more +quickly you could solve it if you just + + align:start position:0% +quickly you could solve it if you just + + + align:start position:0% +quickly you could solve it if you just +thought for an hour you might have saved + + align:start position:0% +thought for an hour you might have saved + + + align:start position:0% +thought for an hour you might have saved +a million hours of computer time right + + align:start position:0% +a million hours of computer time right + + + align:start position:0% +a million hours of computer time right +seriously so those that balance always + + align:start position:0% +seriously so those that balance always + + + align:start position:0% +seriously so those that balance always +has has to be kept in mind and then the + + align:start position:0% +has has to be kept in mind and then the + + + align:start position:0% +has has to be kept in mind and then the +one i' like to add is Spider-Man's Uncle + + align:start position:0% +one i' like to add is Spider-Man's Uncle + + + align:start position:0% +one i' like to add is Spider-Man's Uncle +with great power comes great + + align:start position:0% +with great power comes great + + + align:start position:0% +with great power comes great +responsibility because you have now + + align:start position:0% +responsibility because you have now + + + align:start position:0% +responsibility because you have now +power you're gaining power that's what + + align:start position:0% +power you're gaining power that's what + + + align:start position:0% +power you're gaining power that's what +this class is doing to you you're + + align:start position:0% +this class is doing to you you're + + + align:start position:0% +this class is doing to you you're +gaining the power to calculate things + + align:start position:0% +gaining the power to calculate things + + + align:start position:0% +gaining the power to calculate things +like band structures right and the + + align:start position:0% +like band structures right and the + + + align:start position:0% +like band structures right and the +responsibility is that you I want you to + + align:start position:0% +responsibility is that you I want you to + + + align:start position:0% +responsibility is that you I want you to +know what you're doing in the sense that + + align:start position:0% +know what you're doing in the sense that + + + align:start position:0% +know what you're doing in the sense that +you know you don't just say I'm going to + + align:start position:0% +you know you don't just say I'm going to + + + align:start position:0% +you know you don't just say I'm going to +do a band structure oh here it is that + + align:start position:0% +do a band structure oh here it is that + + + align:start position:0% +do a band structure oh here it is that +you check and you you you're you're + + align:start position:0% +you check and you you you're you're + + + align:start position:0% +you check and you you you're you're +careful about it right and you + + align:start position:0% +careful about it right and you + + + align:start position:0% +careful about it right and you +understand how to validate the + + align:start position:0% +understand how to validate the + + + align:start position:0% +understand how to validate the +calculations that you're doing against + + align:start position:0% +calculations that you're doing against + + + align:start position:0% +calculations that you're doing against +uh experiment right you understand how + + align:start position:0% +uh experiment right you understand how + + + align:start position:0% +uh experiment right you understand how +to converge the + + align:start position:0% +to converge the + + + align:start position:0% +to converge the +calculations right you understand how to + + align:start position:0% +calculations right you understand how to + + + align:start position:0% +calculations right you understand how to +make sure you understand what they mean + + align:start position:0% +make sure you understand what they mean + + + align:start position:0% +make sure you understand what they mean +that's the responsibility okay so um a + + align:start position:0% +that's the responsibility okay so um a + + + align:start position:0% +that's the responsibility okay so um a +little bit of philosophy there anyway + + align:start position:0% +little bit of philosophy there anyway + + + align:start position:0% +little bit of philosophy there anyway +okay we're going to review a little bit + + align:start position:0% +okay we're going to review a little bit + + + align:start position:0% +okay we're going to review a little bit +and we'll talk about some properties + + align:start position:0% +and we'll talk about some properties + + + align:start position:0% +and we'll talk about some properties +we'll come back to this band structure + + align:start position:0% +we'll come back to this band structure + + + align:start position:0% +we'll come back to this band structure +which is is so critical to um this part + + align:start position:0% +which is is so critical to um this part + + + align:start position:0% +which is is so critical to um this part +of of the class um and if I have time + + align:start position:0% +of of the class um and if I have time + + + align:start position:0% +of of the class um and if I have time +I'll talk about magnetization but + + align:start position:0% +I'll talk about magnetization but + + + align:start position:0% +I'll talk about magnetization but +probably I'll I'll talk about + + align:start position:0% +probably I'll I'll talk about + + + align:start position:0% +probably I'll I'll talk about +magnetization on on Thursday a little + + align:start position:0% +magnetization on on Thursday a little + + + align:start position:0% +magnetization on on Thursday a little +all + + align:start position:0% +all + + + align:start position:0% +all +right any questions so we've had a a + + align:start position:0% +right any questions so we've had a a + + + align:start position:0% +right any questions so we've had a a +wrap video some + + align:start position:0% +wrap video some + + + align:start position:0% +wrap video some +philosophy a little bit of an outline + + align:start position:0% +philosophy a little bit of an outline + + + align:start position:0% +philosophy a little bit of an outline +where else could we go right things are + + align:start position:0% +where else could we go right things are + + + align:start position:0% +where else could we go right things are +good Rondo did what's up with that was + + align:start position:0% +good Rondo did what's up with that was + + + align:start position:0% +good Rondo did what's up with that was +that a good decision no how many people + + align:start position:0% +that a good decision no how many people + + + align:start position:0% +that a good decision no how many people +saw that I just want to know okay so a + + align:start position:0% +saw that I just want to know okay so a + + + align:start position:0% +saw that I just want to know okay so a +little more people are wa but you only + + align:start position:0% +little more people are wa but you only + + + align:start position:0% +little more people are wa but you only +saw it on a highlight oh you watched the + + align:start position:0% +saw it on a highlight oh you watched the + + + align:start position:0% +saw it on a highlight oh you watched the +game all right + + align:start position:0% +game all right + + + align:start position:0% +game all right +good yeah but they're going to win + + align:start position:0% +good yeah but they're going to win + + + align:start position:0% +good yeah but they're going to win +without Rondo tonight anyway okay yeah + + align:start position:0% +without Rondo tonight anyway okay yeah + + + align:start position:0% +without Rondo tonight anyway okay yeah +you bump a ref on purpose come on come + + align:start position:0% +you bump a ref on purpose come on come + + + align:start position:0% +you bump a ref on purpose come on come +on man anyway I can't I can't spend more + + align:start position:0% +on man anyway I can't I can't spend more + + + align:start position:0% +on man anyway I can't I can't spend more +time on it I don't want to do that um + + align:start position:0% +time on it I don't want to do that um + + + align:start position:0% +time on it I don't want to do that um +let's take a walk through memory lane + + align:start position:0% +let's take a walk through memory lane + + + align:start position:0% +let's take a walk through memory lane +for just a moment because I want to make + + align:start position:0% +for just a moment because I want to make + + + align:start position:0% +for just a moment because I want to make +sure we all know where we are + + align:start position:0% +sure we all know where we are + + + align:start position:0% +sure we all know where we are +right we started with this there were + + align:start position:0% +right we started with this there were + + + align:start position:0% +right we started with this there were +some strange observations by some very + + align:start position:0% +some strange observations by some very + + + align:start position:0% +some strange observations by some very +smart people tell me what those are you + + align:start position:0% +smart people tell me what those are you + + + align:start position:0% +smart people tell me what those are you +know we could ask questions like about + + align:start position:0% +know we could ask questions like about + + + align:start position:0% +know we could ask questions like about +these on the quiz those are electrons + + align:start position:0% +these on the quiz those are electrons + + + align:start position:0% +these on the quiz those are electrons +yeah that's an electron those are + + align:start position:0% +yeah that's an electron those are + + + align:start position:0% +yeah that's an electron those are +electrons what's this + + align:start position:0% +electrons what's this + + + align:start position:0% +electrons what's this +experiment this one is what's this + + align:start position:0% +experiment this one is what's this + + + align:start position:0% +experiment this one is what's this +one why does it + + align:start position:0% + + + + align:start position:0% + +collapse classical then it's got to + + align:start position:0% +collapse classical then it's got to + + + align:start position:0% +collapse classical then it's got to +be what + + align:start position:0% +be what + + + align:start position:0% +be what +energy yeah it's giving off energy and + + align:start position:0% +energy yeah it's giving off energy and + + + align:start position:0% +energy yeah it's giving off energy and +it's not going to hang in to its orbit + + align:start position:0% +it's not going to hang in to its orbit + + + align:start position:0% +it's not going to hang in to its orbit +but then quantum mechanics came along + + align:start position:0% +but then quantum mechanics came along + + + align:start position:0% +but then quantum mechanics came along +and said no that's not true right + + align:start position:0% +and said no that's not true right + + + align:start position:0% +and said no that's not true right +because + + align:start position:0% + + + + align:start position:0% + +what it just it just is it's the it just + + align:start position:0% +what it just it just is it's the it just + + + align:start position:0% +what it just it just is it's the it just +is answer no because what it said is + + align:start position:0% +is answer no because what it said is + + + align:start position:0% +is answer no because what it said is +that the levels of a quantum mechanical + + align:start position:0% +that the levels of a quantum mechanical + + + align:start position:0% +that the levels of a quantum mechanical +object are quantized and they have to be + + align:start position:0% +object are quantized and they have to be + + + align:start position:0% +object are quantized and they have to be +in those places and there's no in + + align:start position:0% +in those places and there's no in + + + align:start position:0% +in those places and there's no in +between and that's what this is + + align:start position:0% +between and that's what this is + + + align:start position:0% +between and that's what this is +what's + + align:start position:0% +what's + + + align:start position:0% +what's +this which comes from that same + + align:start position:0% +this which comes from that same + + + align:start position:0% +this which comes from that same +observation you'd think that the the + + align:start position:0% +observation you'd think that the the + + + align:start position:0% +observation you'd think that the the +universe the hydrogen might emit colors + + align:start position:0% +universe the hydrogen might emit colors + + + align:start position:0% +universe the hydrogen might emit colors +in any frequency but instead only + + align:start position:0% +in any frequency but instead only + + + align:start position:0% +in any frequency but instead only +certain frequencies and it comes from + + align:start position:0% +certain frequencies and it comes from + + + align:start position:0% +certain frequencies and it comes from +that quantization of those electron + + align:start position:0% +that quantization of those electron + + + align:start position:0% +that quantization of those electron +levels and this somebody already said + + align:start position:0% +levels and this somebody already said + + + align:start position:0% +levels and this somebody already said +this right photoelectric effect okay now + + align:start position:0% +this right photoelectric effect okay now + + + align:start position:0% +this right photoelectric effect okay now +those are very smart people so and the + + align:start position:0% +those are very smart people so and the + + + align:start position:0% +those are very smart people so and the +weirdness kept going now is that guy + + align:start position:0% +weirdness kept going now is that guy + + + align:start position:0% +weirdness kept going now is that guy +ordering two drinks at the bar why does + + align:start position:0% +ordering two drinks at the bar why does + + + align:start position:0% +ordering two drinks at the bar why does +he have two + + align:start position:0% +he have two + + + align:start position:0% +he have two +double sled experiment that was a cool + + align:start position:0% +double sled experiment that was a cool + + + align:start position:0% +double sled experiment that was a cool +one um and the weirdness just kept going + + align:start position:0% +one um and the weirdness just kept going + + + align:start position:0% +one um and the weirdness just kept going +right now it became very clear that + + align:start position:0% +right now it became very clear that + + + align:start position:0% +right now it became very clear that +matter behaved like + + align:start position:0% +matter behaved like + + + align:start position:0% +matter behaved like +waves you know if we took this little 10 + + align:start position:0% +waves you know if we took this little 10 + + + align:start position:0% +waves you know if we took this little 10 +slide um kind of where we are quick you + + align:start position:0% +slide um kind of where we are quick you + + + align:start position:0% +slide um kind of where we are quick you +know what road have we come on and we + + align:start position:0% +know what road have we come on and we + + + align:start position:0% +know what road have we come on and we +turned it into a music video + + align:start position:0% +turned it into a music video + + + align:start position:0% +turned it into a music video +right anybody want to do that that's uh + + align:start position:0% +right anybody want to do that that's uh + + + align:start position:0% +right anybody want to do that that's uh +that's exciting okay + + align:start position:0% +that's exciting okay + + + align:start position:0% +that's exciting okay +um became clear that matter behaved like + + align:start position:0% +um became clear that matter behaved like + + + align:start position:0% +um became clear that matter behaved like +waves and vice versa okay um and that we + + align:start position:0% +waves and vice versa okay um and that we + + + align:start position:0% +waves and vice versa okay um and that we +had to lose our sort of classical + + align:start position:0% +had to lose our sort of classical + + + align:start position:0% +had to lose our sort of classical +concepts of absolute position and + + align:start position:0% +concepts of absolute position and + + + align:start position:0% +concepts of absolute position and +momentum and instead consider a particle + + align:start position:0% +momentum and instead consider a particle + + + align:start position:0% +momentum and instead consider a particle +as a wave whose square is the + + align:start position:0% +as a wave whose square is the + + + align:start position:0% +as a wave whose square is the +probability of finding it and there it + + align:start position:0% +probability of finding it and there it + + + align:start position:0% +probability of finding it and there it +is and this became our goal our task of + + align:start position:0% +is and this became our goal our task of + + + align:start position:0% +is and this became our goal our task of +finding that right that's what we needed + + align:start position:0% +finding that right that's what we needed + + + align:start position:0% +finding that right that's what we needed +to do on a computer um oh and there's a + + align:start position:0% +to do on a computer um oh and there's a + + + align:start position:0% +to do on a computer um oh and there's a +picture of a wave right how do we do do + + align:start position:0% +picture of a wave right how do we do do + + + align:start position:0% +picture of a wave right how do we do do +this how do we describe this well um we + + align:start position:0% +this how do we describe this well um we + + + align:start position:0% +this how do we describe this well um we +needed our f equals ma right right so + + align:start position:0% +needed our f equals ma right right so + + + align:start position:0% +needed our f equals ma right right so +when when when matter is just a particle + + align:start position:0% +when when when matter is just a particle + + + align:start position:0% +when when when matter is just a particle +we have fals ma but now that it's a wave + + align:start position:0% +we have fals ma but now that it's a wave + + + align:start position:0% +we have fals ma but now that it's a wave +um we needed something different and and + + align:start position:0% +um we needed something different and and + + + align:start position:0% +um we needed something different and and +from the elements and the bits of pieces + + align:start position:0% +from the elements and the bits of pieces + + + align:start position:0% +from the elements and the bits of pieces +of quantum mechanics which people were + + align:start position:0% +of quantum mechanics which people were + + + align:start position:0% +of quantum mechanics which people were +putting together right um outomes the + + align:start position:0% +putting together right um outomes the + + + align:start position:0% +putting together right um outomes the +shinger equation right and that's our + + align:start position:0% +shinger equation right and that's our + + + align:start position:0% +shinger equation right and that's our +fals ma which tells us how to um how to + + align:start position:0% +fals ma which tells us how to um how to + + + align:start position:0% +fals ma which tells us how to um how to +describ the behavior of waves if they're + + align:start position:0% +describ the behavior of waves if they're + + + align:start position:0% +describ the behavior of waves if they're +quantum mechanical and it was + + align:start position:0% +quantum mechanical and it was + + + align:start position:0% +quantum mechanical and it was +wonderful it explained many things it + + align:start position:0% +wonderful it explained many things it + + + align:start position:0% +wonderful it explained many things it +gave us Atomic orbitals it predicted the + + align:start position:0% +gave us Atomic orbitals it predicted the + + + align:start position:0% +gave us Atomic orbitals it predicted the +energy levels of hydrogen remember how + + align:start position:0% +energy levels of hydrogen remember how + + + align:start position:0% +energy levels of hydrogen remember how +how wonderful that was um it gave us + + align:start position:0% +how wonderful that was um it gave us + + + align:start position:0% +how wonderful that was um it gave us +basically the means to understand a + + align:start position:0% +basically the means to understand a + + + align:start position:0% +basically the means to understand a +whole lot of this right + + align:start position:0% +whole lot of this right + + + align:start position:0% +whole lot of this right +um + + align:start position:0% +um + + + align:start position:0% +um +but right but um it nature does more + + align:start position:0% +but right but um it nature does more + + + align:start position:0% +but right but um it nature does more +than one + + align:start position:0% +than one + + + align:start position:0% +than one +electron and it was impossible to solve + + align:start position:0% +electron and it was impossible to solve + + + align:start position:0% +electron and it was impossible to solve +for more than a single electron so + + align:start position:0% +for more than a single electron so + + + align:start position:0% +for more than a single electron so +here's where computational quantum + + align:start position:0% +here's where computational quantum + + + align:start position:0% +here's where computational quantum +mechanics comes in + + align:start position:0% +mechanics comes in + + + align:start position:0% +mechanics comes in +okay um but there was still a problem + + align:start position:0% +okay um but there was still a problem + + + align:start position:0% +okay um but there was still a problem +and the problem is that we don't have + + align:start position:0% +and the problem is that we don't have + + + align:start position:0% +and the problem is that we don't have +the age of the universe to do our + + align:start position:0% +the age of the universe to do our + + + align:start position:0% +the age of the universe to do our +calculations and so that that's how long + + align:start position:0% +calculations and so that that's how long + + + align:start position:0% +calculations and so that that's how long +it would take to currently solve the + + align:start position:0% +it would take to currently solve the + + + align:start position:0% +it would take to currently solve the +shary equation exactly on a computer for + + align:start position:0% +shary equation exactly on a computer for + + + align:start position:0% +shary equation exactly on a computer for +like only a handful of of particles + + align:start position:0% +like only a handful of of particles + + + align:start position:0% +like only a handful of of particles +right so you know obviously you could + + align:start position:0% +right so you know obviously you could + + + align:start position:0% +right so you know obviously you could +solve it for one or two particles + + align:start position:0% +solve it for one or two particles + + + align:start position:0% +solve it for one or two particles +exactly you know a lot less time than + + align:start position:0% +exactly you know a lot less time than + + + align:start position:0% +exactly you know a lot less time than +that but once you get up to 10 you're + + align:start position:0% +that but once you get up to 10 you're + + + align:start position:0% +that but once you get up to 10 you're +done um and so we we started to try to + + align:start position:0% +done um and so we we started to try to + + + align:start position:0% +done um and so we we started to try to +take some inspiration and we looked at + + align:start position:0% +take some inspiration and we looked at + + + align:start position:0% +take some inspiration and we looked at +this guy's + + align:start position:0% +this guy's + + + align:start position:0% +this guy's +back and we said okay well maybe that's + + align:start position:0% +back and we said okay well maybe that's + + + align:start position:0% +back and we said okay well maybe that's +telling us something it's telling us a + + align:start position:0% +telling us something it's telling us a + + + align:start position:0% +telling us something it's telling us a +lot uh but it's telling us some + + align:start position:0% +lot uh but it's telling us some + + + align:start position:0% +lot uh but it's telling us some +interesting physics it's telling us that + + align:start position:0% +interesting physics it's telling us that + + + align:start position:0% +interesting physics it's telling us that +the ions are a whole lot heavier and + + align:start position:0% +the ions are a whole lot heavier and + + + align:start position:0% +the ions are a whole lot heavier and +slower than the electrons so we can + + align:start position:0% +slower than the electrons so we can + + + align:start position:0% +slower than the electrons so we can +freeze them out right so we started to + + align:start position:0% +freeze them out right so we started to + + + align:start position:0% +freeze them out right so we started to +peel away at the sh your equation and we + + align:start position:0% +peel away at the sh your equation and we + + + align:start position:0% +peel away at the sh your equation and we +made it simpler okay we made some + + align:start position:0% +made it simpler okay we made some + + + align:start position:0% +made it simpler okay we made some +approximations + + align:start position:0% +approximations + + + align:start position:0% +approximations +um and there were basically the two + + align:start position:0% +um and there were basically the two + + + align:start position:0% +um and there were basically the two +paths that I talked about in those + + align:start position:0% +paths that I talked about in those + + + align:start position:0% +paths that I talked about in those +approximations um at the time it's about + + align:start position:0% +approximations um at the time it's about + + + align:start position:0% +approximations um at the time it's about +50 years ago uh maybe 60 um you know + + align:start position:0% +50 years ago uh maybe 60 um you know + + + align:start position:0% +50 years ago uh maybe 60 um you know +these two paths were fairly distinct and + + align:start position:0% +these two paths were fairly distinct and + + + align:start position:0% +these two paths were fairly distinct and +the chemists mostly worked on saying + + align:start position:0% +the chemists mostly worked on saying + + + align:start position:0% +the chemists mostly worked on saying +well here's the equation we have to + + align:start position:0% +well here's the equation we have to + + + align:start position:0% +well here's the equation we have to +solve we can't solve it let's make Sai + + align:start position:0% +solve we can't solve it let's make Sai + + + align:start position:0% +solve we can't solve it let's make Sai +something simpler let's simplify Sai and + + align:start position:0% +something simpler let's simplify Sai and + + + align:start position:0% +something simpler let's simplify Sai and +the physicist sort of most + + align:start position:0% +the physicist sort of most + + + align:start position:0% +the physicist sort of most +said well let's not think about s let's + + align:start position:0% +said well let's not think about s let's + + + align:start position:0% +said well let's not think about s let's +just change the hamiltonian that's H + + align:start position:0% +just change the hamiltonian that's H + + + align:start position:0% +just change the hamiltonian that's H +there right um and those are sort of two + + align:start position:0% +there right um and those are sort of two + + + align:start position:0% +there right um and those are sort of two +um two approaches that led to many + + align:start position:0% +um two approaches that led to many + + + align:start position:0% +um two approaches that led to many +different models many different theories + + align:start position:0% +different models many different theories + + + align:start position:0% +different models many different theories +okay many different theories um in in + + align:start position:0% +okay many different theories um in in + + + align:start position:0% +okay many different theories um in in +the theories in both sides the effect of + + align:start position:0% +the theories in both sides the effect of + + + align:start position:0% +the theories in both sides the effect of +these simplifications led to the um the + + align:start position:0% +these simplifications led to the um the + + + align:start position:0% +these simplifications led to the um the +picture that we call a mean fill picture + + align:start position:0% +picture that we call a mean fill picture + + + align:start position:0% +picture that we call a mean fill picture +which is that instead of having to worry + + align:start position:0% +which is that instead of having to worry + + + align:start position:0% +which is that instead of having to worry +about all these quantum mechanical + + align:start position:0% +about all these quantum mechanical + + + align:start position:0% +about all these quantum mechanical +electrons interacting with each other we + + align:start position:0% +electrons interacting with each other we + + + align:start position:0% +electrons interacting with each other we +just worry about them as if it's each + + align:start position:0% +just worry about them as if it's each + + + align:start position:0% +just worry about them as if it's each +one is in the field of the others an + + align:start position:0% +one is in the field of the others an + + + align:start position:0% +one is in the field of the others an +average field of the others and that's + + align:start position:0% +average field of the others and that's + + + align:start position:0% +average field of the others and that's +called a mean fill method okay those are + + align:start position:0% +called a mean fill method okay those are + + + align:start position:0% +called a mean fill method okay those are +the methods we're using in this class + + align:start position:0% +the methods we're using in this class + + + align:start position:0% +the methods we're using in this class +that's the method we're + + align:start position:0% +that's the method we're + + + align:start position:0% +that's the method we're +using and then we talked about density + + align:start position:0% +using and then we talked about density + + + align:start position:0% +using and then we talked about density +functional + + align:start position:0% +functional + + + align:start position:0% +functional +Theory and um and there the the + + align:start position:0% +Theory and um and there the the + + + align:start position:0% +Theory and um and there the the +Breakthrough there is that you know + + align:start position:0% +Breakthrough there is that you know + + + align:start position:0% +Breakthrough there is that you know +trying to keep track of a wave function + + align:start position:0% +trying to keep track of a wave function + + + align:start position:0% +trying to keep track of a wave function +let's say on a grid of a you know 2x two + + align:start position:0% +let's say on a grid of a you know 2x two + + + align:start position:0% +let's say on a grid of a you know 2x two +Grid or 3x3 or whatever um if you had uh + + align:start position:0% +Grid or 3x3 or whatever um if you had uh + + + align:start position:0% +Grid or 3x3 or whatever um if you had uh +well this is for actually a 2X 2 X2 grid + + align:start position:0% +well this is for actually a 2X 2 X2 grid + + + align:start position:0% +well this is for actually a 2X 2 X2 grid +and you have n partic n + + align:start position:0% +and you have n partic n + + + align:start position:0% +and you have n partic n +electrons well if you just have one if + + align:start position:0% +electrons well if you just have one if + + + align:start position:0% +electrons well if you just have one if +you have n is one so one + + align:start position:0% +you have n is one so one + + + align:start position:0% +you have n is one so one +electron okay you have um eight points + + align:start position:0% +electron okay you have um eight points + + + align:start position:0% +electron okay you have um eight points +you need to keep track of but if you had + + align:start position:0% +you need to keep track of but if you had + + + align:start position:0% +you need to keep track of but if you had +just 10 electrons then um you see that + + align:start position:0% +just 10 electrons then um you see that + + + align:start position:0% +just 10 electrons then um you see that +you go to 10 to the 9th points okay this + + align:start position:0% +you go to 10 to the 9th points okay this + + + align:start position:0% +you go to 10 to the 9th points okay this +is the problem of grids of using grids + + align:start position:0% +is the problem of grids of using grids + + + align:start position:0% +is the problem of grids of using grids +to represent things and so if you use + + align:start position:0% +to represent things and so if you use + + + align:start position:0% +to represent things and so if you use +the density instead it's just a constant + + align:start position:0% +the density instead it's just a constant + + + align:start position:0% +the density instead it's just a constant +right the tracking the density is is + + align:start position:0% +right the tracking the density is is + + + align:start position:0% +right the tracking the density is is +much um easier and and the the Crux of + + align:start position:0% +much um easier and and the the Crux of + + + align:start position:0% +much um easier and and the the Crux of +density functional Theory which was + + align:start position:0% +density functional Theory which was + + + align:start position:0% +density functional Theory which was +worked out in the 60s is that there is a + + align:start position:0% +worked out in the 60s is that there is a + + + align:start position:0% +worked out in the 60s is that there is a +onetoone correspondence between the + + align:start position:0% +onetoone correspondence between the + + + align:start position:0% +onetoone correspondence between the +exact density of the system and the wave + + align:start position:0% +exact density of the system and the wave + + + align:start position:0% +exact density of the system and the wave +function + + align:start position:0% +function + + + align:start position:0% +function +okay um and we talked about this last + + align:start position:0% +okay um and we talked about this last + + + align:start position:0% +okay um and we talked about this last +time about how we sit here because it's + + align:start position:0% +time about how we sit here because it's + + + align:start position:0% +time about how we sit here because it's +a nice compromise between uh accuracy + + align:start position:0% +a nice compromise between uh accuracy + + + align:start position:0% +a nice compromise between uh accuracy +and applicability but I want to come + + align:start position:0% +and applicability but I want to come + + + align:start position:0% +and applicability but I want to come +back to this because this is not you you + + align:start position:0% +back to this because this is not you you + + + align:start position:0% +back to this because this is not you you +know part of the reason I wanted to + + align:start position:0% +know part of the reason I wanted to + + + align:start position:0% +know part of the reason I wanted to +remind you of this is is is it it's just + + align:start position:0% +remind you of this is is is it it's just + + + align:start position:0% +remind you of this is is is it it's just +always fun to take these walks through + + align:start position:0% +always fun to take these walks through + + + align:start position:0% +always fun to take these walks through +memory lane and it only took us 5 + + align:start position:0% +memory lane and it only took us 5 + + + align:start position:0% +memory lane and it only took us 5 +minutes but another reason is that um I + + align:start position:0% +minutes but another reason is that um I + + + align:start position:0% +minutes but another reason is that um I +want to remind you that we are not + + align:start position:0% +want to remind you that we are not + + + align:start position:0% +want to remind you that we are not +solving for quantum mechanics exactly + + align:start position:0% +solving for quantum mechanics exactly + + + align:start position:0% +solving for quantum mechanics exactly +we're not we cannot okay and so um and + + align:start position:0% +we're not we cannot okay and so um and + + + align:start position:0% +we're not we cannot okay and so um and +so this is not you you this is what I + + align:start position:0% +so this is not you you this is what I + + + align:start position:0% +so this is not you you this is what I +mean by the + + align:start position:0% +mean by the + + + align:start position:0% +mean by the +responsibility part okay there are some + + align:start position:0% +responsibility part okay there are some + + + align:start position:0% +responsibility part okay there are some +things that DFT um can can give you can + + align:start position:0% +things that DFT um can can give you can + + + align:start position:0% +things that DFT um can can give you can +calculate about those electrons that + + align:start position:0% +calculate about those electrons that + + + align:start position:0% +calculate about those electrons that +that are typically very accurate but + + align:start position:0% +that are typically very accurate but + + + align:start position:0% +that are typically very accurate but +there are some things where it's + + align:start position:0% +there are some things where it's + + + align:start position:0% +there are some things where it's +actually quite off okay it's an + + align:start position:0% +actually quite off okay it's an + + + align:start position:0% +actually quite off okay it's an +approximation does anybody remember what + + align:start position:0% +approximation does anybody remember what + + + align:start position:0% +approximation does anybody remember what +where it it tends to do well I I did + + align:start position:0% +where it it tends to do well I I did + + + align:start position:0% +where it it tends to do well I I did +talk about this in the third or fourth + + align:start position:0% +talk about this in the third or fourth + + + align:start position:0% +talk about this in the third or fourth +lecture and where it tends to do badly + + align:start position:0% +lecture and where it tends to do badly + + + align:start position:0% +lecture and where it tends to do badly +you know or one of those + + align:start position:0% + + + + align:start position:0% + +two structur okay what about the solids + + align:start position:0% +two structur okay what about the solids + + + align:start position:0% +two structur okay what about the solids +what properties + + align:start position:0% + + + + align:start position:0% + +yeah that would be a case where it falls + + align:start position:0% +yeah that would be a case where it falls + + + align:start position:0% +yeah that would be a case where it falls +into the not so well + + align:start position:0% +into the not so well + + + align:start position:0% +into the not so well +category + + align:start position:0% +category + + + align:start position:0% +category +okay so this is pretty important so + + align:start position:0% +okay so this is pretty important so + + + align:start position:0% +okay so this is pretty important so +um lce parameters yes it tends to do + + align:start position:0% +um lce parameters yes it tends to do + + + align:start position:0% +um lce parameters yes it tends to do +very well for Lattis parameters so the + + align:start position:0% +very well for Lattis parameters so the + + + align:start position:0% +very well for Lattis parameters so the +you know how far apart should atoms be + + align:start position:0% +you know how far apart should atoms be + + + align:start position:0% +you know how far apart should atoms be +if they come together in a molecule or + + align:start position:0% +if they come together in a molecule or + + + align:start position:0% +if they come together in a molecule or +solid or liquid DFT can do very well um + + align:start position:0% +solid or liquid DFT can do very well um + + + align:start position:0% +solid or liquid DFT can do very well um +it does very well for vibrational + + align:start position:0% +it does very well for vibrational + + + align:start position:0% +it does very well for vibrational +properties vibrational Spectrum right + + align:start position:0% +properties vibrational Spectrum right + + + align:start position:0% +properties vibrational Spectrum right +the bons in a + + align:start position:0% +the bons in a + + + align:start position:0% +the bons in a +material it tends to do worse for + + align:start position:0% +material it tends to do worse for + + + align:start position:0% +material it tends to do worse for +excited States like you know looking at + + align:start position:0% +excited States like you know looking at + + + align:start position:0% +excited States like you know looking at +say the optical Gap or the electronic + + align:start position:0% +say the optical Gap or the electronic + + + align:start position:0% +say the optical Gap or the electronic +gap of material is um it it tends to to + + align:start position:0% +gap of material is um it it tends to to + + + align:start position:0% +gap of material is um it it tends to to +uh you know the approximations that we + + align:start position:0% +uh you know the approximations that we + + + align:start position:0% +uh you know the approximations that we +had to use to get a method that's + + align:start position:0% +had to use to get a method that's + + + align:start position:0% +had to use to get a method that's +workable all of these have + + align:start position:0% +workable all of these have + + + align:start position:0% +workable all of these have +approximations except this see we're up + + align:start position:0% +approximations except this see we're up + + + align:start position:0% +approximations except this see we're up +to two electrons here um uh those + + align:start position:0% +to two electrons here um uh those + + + align:start position:0% +to two electrons here um uh those +approximations um lead to DFT uh not + + align:start position:0% +approximations um lead to DFT uh not + + + align:start position:0% +approximations um lead to DFT uh not +doing so well for the back for the Gap + + align:start position:0% +doing so well for the back for the Gap + + + align:start position:0% +doing so well for the back for the Gap +however um as you may have noticed in + + align:start position:0% +however um as you may have noticed in + + + align:start position:0% +however um as you may have noticed in +your homeworks that's one of the things + + align:start position:0% +your homeworks that's one of the things + + + align:start position:0% +your homeworks that's one of the things +you have to calculate in your second + + align:start position:0% +you have to calculate in your second + + + align:start position:0% +you have to calculate in your second +homework right so here's the point I + + align:start position:0% +homework right so here's the point I + + + align:start position:0% +homework right so here's the point I +want to make um these methods have + + align:start position:0% +want to make um these methods have + + + align:start position:0% +want to make um these methods have +advantages and disadvantages they all + + align:start position:0% +advantages and disadvantages they all + + + align:start position:0% +advantages and disadvantages they all +are approximate some quantum mechanical + + align:start position:0% +are approximate some quantum mechanical + + + align:start position:0% +are approximate some quantum mechanical +methods can describe some things very + + align:start position:0% +methods can describe some things very + + + align:start position:0% +methods can describe some things very +accurately and some things um not as + + align:start position:0% +accurately and some things um not as + + + align:start position:0% +accurately and some things um not as +accurately and others may have different + + align:start position:0% +accurately and others may have different + + + align:start position:0% +accurately and others may have different +balances and as you go down to more + + align:start position:0% +balances and as you go down to more + + + align:start position:0% +balances and as you go down to more +accurate methods that can describe more + + align:start position:0% +accurate methods that can describe more + + + align:start position:0% +accurate methods that can describe more +things very accurately you tend to be + + align:start position:0% +things very accurately you tend to be + + + align:start position:0% +things very accurately you tend to be +able to do less and less numbers of + + align:start position:0% +able to do less and less numbers of + + + align:start position:0% +able to do less and less numbers of +electrons right limit your phase space + + align:start position:0% +electrons right limit your phase space + + + align:start position:0% +electrons right limit your phase space +to you know 12 20 electrons and you're + + align:start position:0% +to you know 12 20 electrons and you're + + + align:start position:0% +to you know 12 20 electrons and you're +pretty Limited in in how many materials + + align:start position:0% +pretty Limited in in how many materials + + + align:start position:0% +pretty Limited in in how many materials +you can explore right so um uh uh now + + align:start position:0% +you can explore right so um uh uh now + + + align:start position:0% +you can explore right so um uh uh now +why can we still calculate the Gap well + + align:start position:0% +why can we still calculate the Gap well + + + align:start position:0% +why can we still calculate the Gap well +and this is actually there's going to be + + align:start position:0% +and this is actually there's going to be + + + align:start position:0% +and this is actually there's going to be +an addendum to your homework okay which + + align:start position:0% +an addendum to your homework okay which + + + align:start position:0% +an addendum to your homework okay which +um I'm gonna have to um I forgot to put + + align:start position:0% +um I'm gonna have to um I forgot to put + + + align:start position:0% +um I'm gonna have to um I forgot to put +this in there but um you know if this is + + align:start position:0% +this in there but um you know if this is + + + align:start position:0% +this in there but um you know if this is +the density of + + align:start position:0% + + + + align:start position:0% + +States okay let's say that's the den of + + align:start position:0% +States okay let's say that's the den of + + + align:start position:0% +States okay let's say that's the den of +States um by the way if I asked you + + align:start position:0% +States um by the way if I asked you + + + align:start position:0% +States um by the way if I asked you +what's the gap of this material um what + + align:start position:0% +what's the gap of this material um what + + + align:start position:0% +what's the gap of this material um what +would you + + align:start position:0% + + + + align:start position:0% + +say yeah is between the first + + align:start position:0% +say yeah is between the first + + + align:start position:0% +say yeah is between the first +well that would be true but I need to + + align:start position:0% +well that would be true but I need to + + + align:start position:0% +well that would be true but I need to +know one thing very importantly or I + + align:start position:0% +know one thing very importantly or I + + + align:start position:0% +know one thing very importantly or I +cannot answer whether that's the case + + align:start position:0% +cannot answer whether that's the case + + + align:start position:0% +cannot answer whether that's the case +what do I need to + + align:start position:0% +what do I need to + + + align:start position:0% +what do I need to +know I need to know the position of + + align:start position:0% +know I need to know the position of + + + align:start position:0% +know I need to know the position of +something + + align:start position:0% +something + + + align:start position:0% +something +here the firmy energy who said that very + + align:start position:0% +here the firmy energy who said that very + + + align:start position:0% +here the firmy energy who said that very +good FM energy came from over there okay + + align:start position:0% +good FM energy came from over there okay + + + align:start position:0% +good FM energy came from over there okay +now if I tell you that the FM energy in + + align:start position:0% +now if I tell you that the FM energy in + + + align:start position:0% +now if I tell you that the FM energy in +is here then you're absolutely right + + align:start position:0% +is here then you're absolutely right + + + align:start position:0% +is here then you're absolutely right +it's the it's the difference and and in + + align:start position:0% +it's the it's the difference and and in + + + align:start position:0% +it's the it's the difference and and in +the in the Dos plots you get on the Nano + + align:start position:0% +the in the Dos plots you get on the Nano + + + align:start position:0% +the in the Dos plots you get on the Nano +Hub it's it's these are enally levels + + align:start position:0% +Hub it's it's these are enally levels + + + align:start position:0% +Hub it's it's these are enally levels +that come out um you know if it's a + + align:start position:0% +that come out um you know if it's a + + + align:start position:0% +that come out um you know if it's a +molecule they're levels that come out + + align:start position:0% +molecule they're levels that come out + + + align:start position:0% +molecule they're levels that come out +and then they're spread out a little bit + + align:start position:0% +and then they're spread out a little bit + + + align:start position:0% +and then they're spread out a little bit +so it's very likely this peak height + + align:start position:0% +so it's very likely this peak height + + + align:start position:0% +so it's very likely this peak height +versus that is going to give you the + + align:start position:0% +versus that is going to give you the + + + align:start position:0% +versus that is going to give you the +Gap okay and in in the nanohub tool the + + align:start position:0% +Gap okay and in in the nanohub tool the + + + align:start position:0% +Gap okay and in in the nanohub tool the +the firmy energy is always set to zero + + align:start position:0% +the firmy energy is always set to zero + + + align:start position:0% +the firmy energy is always set to zero +for you okay but if I don't specify it + + align:start position:0% +for you okay but if I don't specify it + + + align:start position:0% +for you okay but if I don't specify it +you may not + + align:start position:0% +you may not + + + align:start position:0% +you may not +know now is that a semiconductor or an + + align:start position:0% +know now is that a semiconductor or an + + + align:start position:0% +know now is that a semiconductor or an +insulator is it a + + align:start position:0% + + + + align:start position:0% + +metal semiconductor how do you know you + + align:start position:0% +metal semiconductor how do you know you + + + align:start position:0% +metal semiconductor how do you know you +have a feeling okay well let's say I put + + align:start position:0% +have a feeling okay well let's say I put + + + align:start position:0% +have a feeling okay well let's say I put +it + + align:start position:0% + + + + align:start position:0% + +here semiconductor + + align:start position:0% +here semiconductor + + + align:start position:0% +here semiconductor +insulator wait why why can I not answer + + align:start position:0% +insulator wait why why can I not answer + + + align:start position:0% +insulator wait why why can I not answer +that question what don't you + + align:start position:0% +that question what don't you + + + align:start position:0% +that question what don't you +know how how big of what what if I told + + align:start position:0% +know how how big of what what if I told + + + align:start position:0% +know how how big of what what if I told +you that this was + + align:start position:0% +you that this was + + + align:start position:0% +you that this was +0.1 and this was 0.2 and the scale is an + + align:start position:0% +0.1 and this was 0.2 and the scale is an + + + align:start position:0% +0.1 and this was 0.2 and the scale is an +EV then what is it + + align:start position:0% +EV then what is it + + + align:start position:0% +EV then what is it +it's a 0.1 EV Gap semiconductor right + + align:start position:0% +it's a 0.1 EV Gap semiconductor right + + + align:start position:0% +it's a 0.1 EV Gap semiconductor right +okay so well that's sort of like almost + + align:start position:0% +okay so well that's sort of like almost + + + align:start position:0% +okay so well that's sort of like almost +the metal but it's still a semiconductor + + align:start position:0% +the metal but it's still a semiconductor + + + align:start position:0% +the metal but it's still a semiconductor +it's a very low band Gap semiconductor + + align:start position:0% +it's a very low band Gap semiconductor + + + align:start position:0% +it's a very low band Gap semiconductor +that where actually electrons will + + align:start position:0% +that where actually electrons will + + + align:start position:0% +that where actually electrons will +probably populate um the conduction band + + align:start position:0% +probably populate um the conduction band + + + align:start position:0% +probably populate um the conduction band +just thermally to to you know an + + align:start position:0% +just thermally to to you know an + + + align:start position:0% +just thermally to to you know an +interesting probability um now uh if I + + align:start position:0% +interesting probability um now uh if I + + + align:start position:0% +interesting probability um now uh if I +told you this was 10 EV what would it + + align:start position:0% + + + + align:start position:0% + +be insulator okay now um and and and I + + align:start position:0% +be insulator okay now um and and and I + + + align:start position:0% +be insulator okay now um and and and I +I'm going to go on Don't worry um but + + align:start position:0% +I'm going to go on Don't worry um but + + + align:start position:0% +I'm going to go on Don't worry um but +the last point is dftt I'm I'm I'm not + + align:start position:0% +the last point is dftt I'm I'm I'm not + + + align:start position:0% +the last point is dftt I'm I'm I'm not +going to go into the the details of why + + align:start position:0% +going to go into the the details of why + + + align:start position:0% +going to go into the the details of why +but DFT tends to underestimate the band + + align:start position:0% +but DFT tends to underestimate the band + + + align:start position:0% +but DFT tends to underestimate the band +Gap okay and + + align:start position:0% +Gap okay and + + + align:start position:0% +Gap okay and +so there are now sophisticated ways of + + align:start position:0% +so there are now sophisticated ways of + + + align:start position:0% +so there are now sophisticated ways of +correcting that and going Beyond DFT + + align:start position:0% +correcting that and going Beyond DFT + + + align:start position:0% +correcting that and going Beyond DFT +that we're not going to talk about in + + align:start position:0% +that we're not going to talk about in + + + align:start position:0% +that we're not going to talk about in +this class but what we are going to do + + align:start position:0% +this class but what we are going to do + + + align:start position:0% +this class but what we are going to do +is we're going to use an approximation + + align:start position:0% +is we're going to use an approximation + + + align:start position:0% +is we're going to use an approximation +that was used for 20 years in the + + align:start position:0% +that was used for 20 years in the + + + align:start position:0% +that was used for 20 years in the +scientific literature and Community um + + align:start position:0% +scientific literature and Community um + + + align:start position:0% +scientific literature and Community um +to correct for this problem and that is + + align:start position:0% +to correct for this problem and that is + + + align:start position:0% +to correct for this problem and that is +simply called a scissor shift where + + align:start position:0% +simply called a scissor shift where + + + align:start position:0% +simply called a scissor shift where +basically you see DFT gets the band Gap + + align:start position:0% +basically you see DFT gets the band Gap + + + align:start position:0% +basically you see DFT gets the band Gap +wrong but it gets qualitatively very + + align:start position:0% +wrong but it gets qualitatively very + + + align:start position:0% +wrong but it gets qualitatively very +often the picture right it just gets the + + align:start position:0% +often the picture right it just gets the + + + align:start position:0% +often the picture right it just gets the +bang Gap too small so very often we just + + align:start position:0% +bang Gap too small so very often we just + + + align:start position:0% +bang Gap too small so very often we just +shift the conduction band + + align:start position:0% +shift the conduction band + + + align:start position:0% +shift the conduction band +states by some some correction + + align:start position:0% + + + + align:start position:0% + +okay I will give you that correction + + align:start position:0% +okay I will give you that correction + + + align:start position:0% +okay I will give you that correction +that'll be the addendum in in the + + align:start position:0% +that'll be the addendum in in the + + + align:start position:0% +that'll be the addendum in in the +homework because you you'll need that so + + align:start position:0% +homework because you you'll need that so + + + align:start position:0% +homework because you you'll need that so +that the Dos plots that you calculate + + align:start position:0% +that the Dos plots that you calculate + + + align:start position:0% +that the Dos plots that you calculate +for these solar + + align:start position:0% +for these solar + + + align:start position:0% +for these solar +fuels think of them as as pretty good + + align:start position:0% +fuels think of them as as pretty good + + + align:start position:0% +fuels think of them as as pretty good +except you have to shift these states up + + align:start position:0% +except you have to shift these states up + + + align:start position:0% +except you have to shift these states up +so qualitatively these states are not + + align:start position:0% +so qualitatively these states are not + + + align:start position:0% +so qualitatively these states are not +are are not bad but they're just too low + + align:start position:0% +are are not bad but they're just too low + + + align:start position:0% +are are not bad but they're just too low +in energy compared to the to the + + align:start position:0% +in energy compared to the to the + + + align:start position:0% +in energy compared to the to the +occupied States okay so that's um that's + + align:start position:0% +occupied States okay so that's um that's + + + align:start position:0% +occupied States okay so that's um that's +a method that um is not really used very + + align:start position:0% +a method that um is not really used very + + + align:start position:0% +a method that um is not really used very +often anymore but it was used heavily in + + align:start position:0% +often anymore but it was used heavily in + + + align:start position:0% +often anymore but it was used heavily in +the 70s and 80s to use DFT um to look at + + align:start position:0% +the 70s and 80s to use DFT um to look at + + + align:start position:0% +the 70s and 80s to use DFT um to look at +at Doss and band structures + + align:start position:0% +at Doss and band structures + + + align:start position:0% +at Doss and band structures +um nowadays we do have methods that go + + align:start position:0% +um nowadays we do have methods that go + + + align:start position:0% +um nowadays we do have methods that go +further that allow us to to actually + + align:start position:0% +further that allow us to to actually + + + align:start position:0% +further that allow us to to actually +calculate these things without some sort + + align:start position:0% +calculate these things without some sort + + + align:start position:0% +calculate these things without some sort +of rigid shift approximation but + + align:start position:0% +of rigid shift approximation but + + + align:start position:0% +of rigid shift approximation but +calculate them more from first + + align:start position:0% +calculate them more from first + + + align:start position:0% +calculate them more from first +principles but I won't go into those in + + align:start position:0% +principles but I won't go into those in + + + align:start position:0% +principles but I won't go into those in +this class okay any questions so you'll + + align:start position:0% +this class okay any questions so you'll + + + align:start position:0% +this class okay any questions so you'll +have to download your dos plot and do + + align:start position:0% +have to download your dos plot and do + + + align:start position:0% +have to download your dos plot and do +the shift that I give you to the data + + align:start position:0% +the shift that I give you to the data + + + align:start position:0% +the shift that I give you to the data +all + + align:start position:0% +all + + + align:start position:0% +all +right seems kind of like a + + align:start position:0% +right seems kind of like a + + + align:start position:0% +right seems kind of like a +cheat you know and it actually is a + + align:start position:0% +cheat you know and it actually is a + + + align:start position:0% +cheat you know and it actually is a +cheat but um like I said the qualitative + + align:start position:0% +cheat but um like I said the qualitative + + + align:start position:0% +cheat but um like I said the qualitative +nature of these states is still very + + align:start position:0% +nature of these states is still very + + + align:start position:0% +nature of these states is still very +good often okay so that's a property DFT + + align:start position:0% +good often okay so that's a property DFT + + + align:start position:0% +good often okay so that's a property DFT +does not do so well + + align:start position:0% +does not do so well + + + align:start position:0% +does not do so well +on okay I won't go through the the + + align:start position:0% +on okay I won't go through the the + + + align:start position:0% +on okay I won't go through the the +self-consistence cycle what what we did + + align:start position:0% +self-consistence cycle what what we did + + + align:start position:0% +self-consistence cycle what what we did +on + + align:start position:0% +on + + + align:start position:0% +on +Tuesday is we talked about solids okay + + align:start position:0% +Tuesday is we talked about solids okay + + + align:start position:0% +Tuesday is we talked about solids okay +so we talked about the periodic cell and + + align:start position:0% +so we talked about the periodic cell and + + + align:start position:0% +so we talked about the periodic cell and +we talked about Crystal symmetries and + + align:start position:0% +we talked about Crystal symmetries and + + + align:start position:0% +we talked about Crystal symmetries and +this was all review I think for most of + + align:start position:0% +this was all review I think for most of + + + align:start position:0% +this was all review I think for most of +you and most symmetries are um most + + align:start position:0% +you and most symmetries are um most + + + align:start position:0% +you and most symmetries are um most +common lates are cubic or hexagonal Clos + + align:start position:0% +common lates are cubic or hexagonal Clos + + + align:start position:0% +common lates are cubic or hexagonal Clos +pack anybody know + + align:start position:0% +pack anybody know + + + align:start position:0% +pack anybody know +why + + align:start position:0% +why + + + align:start position:0% +why +yeah yeah get to because of + + align:start position:0% +yeah yeah get to because of + + + align:start position:0% +yeah yeah get to because of +what yeah kind of pack them in right + + align:start position:0% +what yeah kind of pack them in right + + + align:start position:0% +what yeah kind of pack them in right +makes sense okay um and then and this is + + align:start position:0% +makes sense okay um and then and this is + + + align:start position:0% +makes sense okay um and then and this is +sort of where we spent some time Tuesday + + align:start position:0% +sort of where we spent some time Tuesday + + + align:start position:0% +sort of where we spent some time Tuesday +and I want to make sure we we feel our + + align:start position:0% +and I want to make sure we we feel our + + + align:start position:0% +and I want to make sure we we feel our +Oneness with this Cas Spas thing so + + align:start position:0% +Oneness with this Cas Spas thing so + + + align:start position:0% +Oneness with this Cas Spas thing so +associated with real space latus there + + align:start position:0% +associated with real space latus there + + + align:start position:0% +associated with real space latus there +exists something we call reciprocal lce + + align:start position:0% +exists something we call reciprocal lce + + + align:start position:0% +exists something we call reciprocal lce +it's a set of wave vectors which are + + align:start position:0% +it's a set of wave vectors which are + + + align:start position:0% +it's a set of wave vectors which are +commensurate with the real space lattice + + align:start position:0% +commensurate with the real space lattice + + + align:start position:0% +commensurate with the real space lattice +sometimes we call it + + align:start position:0% +sometimes we call it + + + align:start position:0% +sometimes we call it +g yeah why not those are the lce vectors + + align:start position:0% +g yeah why not those are the lce vectors + + + align:start position:0% +g yeah why not those are the lce vectors +in reciprocal space and we Define them + + align:start position:0% +in reciprocal space and we Define them + + + align:start position:0% +in reciprocal space and we Define them +as you know a star B Star C star um + + align:start position:0% +as you know a star B Star C star um + + + align:start position:0% +as you know a star B Star C star um +that's a lce in real space FC uh BCC BCC + + align:start position:0% +that's a lce in real space FC uh BCC BCC + + + align:start position:0% +that's a lce in real space FC uh BCC BCC +lattice and there's the reciprocal space + + align:start position:0% +lattice and there's the reciprocal space + + + align:start position:0% +lattice and there's the reciprocal space +lattice it's a real lce it has like + + align:start position:0% +lattice it's a real lce it has like + + + align:start position:0% +lattice it's a real lce it has like +distances in lattice World in reciprocal + + align:start position:0% +distances in lattice World in reciprocal + + + align:start position:0% +distances in lattice World in reciprocal +lattice world right it just looks looks + + align:start position:0% +lattice world right it just looks looks + + + align:start position:0% +lattice world right it just looks looks +different and actually the inverse of + + align:start position:0% +different and actually the inverse of + + + align:start position:0% +different and actually the inverse of +BCC is FCC okay so we talked about all + + align:start position:0% +BCC is FCC okay so we talked about all + + + align:start position:0% +BCC is FCC okay so we talked about all +this and then we talked about how you + + align:start position:0% +this and then we talked about how you + + + align:start position:0% +this and then we talked about how you +can define a Zone within reciprocal + + align:start position:0% +can define a Zone within reciprocal + + + align:start position:0% +can define a Zone within reciprocal +space and the first um if you take you + + align:start position:0% +space and the first um if you take you + + + align:start position:0% +space and the first um if you take you +know if you if you draw lines between + + align:start position:0% +know if you if you draw lines between + + + align:start position:0% +know if you if you draw lines between +neighbors and nearest neighbors and you + + align:start position:0% +neighbors and nearest neighbors and you + + + align:start position:0% +neighbors and nearest neighbors and you +draw bisections then you define that + + align:start position:0% +draw bisections then you define that + + + align:start position:0% +draw bisections then you define that +zone right and that's called The brillin + + align:start position:0% +zone right and that's called The brillin + + + align:start position:0% +zone right and that's called The brillin +Zone and so you see here in this Square + + align:start position:0% +Zone and so you see here in this Square + + + align:start position:0% +Zone and so you see here in this Square +lattice it's a square um in here it's + + align:start position:0% +lattice it's a square um in here it's + + + align:start position:0% +lattice it's a square um in here it's +going to be a hexagon and if we Define + + align:start position:0% +going to be a hexagon and if we Define + + + align:start position:0% +going to be a hexagon and if we Define +that zone in three dimensions um well + + align:start position:0% +that zone in three dimensions um well + + + align:start position:0% +that zone in three dimensions um well +here it's squares and hexagons right um + + align:start position:0% +here it's squares and hexagons right um + + + align:start position:0% +here it's squares and hexagons right um +on the on the edges but it's a + + align:start position:0% +on the on the edges but it's a + + + align:start position:0% +on the on the edges but it's a +volume okay does everybody so we're just + + align:start position:0% +volume okay does everybody so we're just + + + align:start position:0% +volume okay does everybody so we're just +defining space still and then came the + + align:start position:0% +defining space still and then came the + + + align:start position:0% +defining space still and then came the +blocks + + align:start position:0% +blocks + + + align:start position:0% +blocks +theorem and in blocks + + align:start position:0% +theorem and in blocks + + + align:start position:0% +theorem and in blocks +theorem you know what we said is that + + align:start position:0% +theorem you know what we said is that + + + align:start position:0% +theorem you know what we said is that +you know values of a function like the + + align:start position:0% +you know values of a function like the + + + align:start position:0% +you know values of a function like the +density should be the same because it's + + align:start position:0% +density should be the same because it's + + + align:start position:0% +density should be the same because it's +a crystal um but the wave function is + + align:start position:0% +a crystal um but the wave function is + + + align:start position:0% +a crystal um but the wave function is +periodic only when multiplied by a phase + + align:start position:0% +periodic only when multiplied by a phase + + + align:start position:0% +periodic only when multiplied by a phase +factor and that's you know I didn't go + + align:start position:0% +factor and that's you know I didn't go + + + align:start position:0% +factor and that's you know I didn't go +into a lot of detail but that's block + + align:start position:0% +into a lot of detail but that's block + + + align:start position:0% +into a lot of detail but that's block +theerum so it says that the wave + + align:start position:0% +theerum so it says that the wave + + + align:start position:0% +theerum so it says that the wave +function picks up a phase factor which + + align:start position:0% +function picks up a phase factor which + + + align:start position:0% +function picks up a phase factor which +depends on this new quantum + + align:start position:0% +depends on this new quantum + + + align:start position:0% +depends on this new quantum +number okay that's all review from + + align:start position:0% +number okay that's all review from + + + align:start position:0% +number okay that's all review from +Tuesday from last week and um and and + + align:start position:0% +Tuesday from last week and um and and + + + align:start position:0% +Tuesday from last week and um and and +you can see that if the wave function + + align:start position:0% +you can see that if the wave function + + + align:start position:0% +you can see that if the wave function +looks like that so if you add um the + + align:start position:0% +looks like that so if you add um the + + + align:start position:0% +looks like that so if you add um the +periodicity of the lattice as Big R R is + + align:start position:0% +periodicity of the lattice as Big R R is + + + align:start position:0% +periodicity of the lattice as Big R R is +just anywhere in real space then you're + + align:start position:0% +just anywhere in real space then you're + + + align:start position:0% +just anywhere in real space then you're +going to get the space factor and if you + + align:start position:0% +going to get the space factor and if you + + + align:start position:0% +going to get the space factor and if you +square them say to get the density then + + align:start position:0% +square them say to get the density then + + + align:start position:0% +square them say to get the density then +you can show that the dens densities are + + align:start position:0% +you can show that the dens densities are + + + align:start position:0% +you can show that the dens densities are +are the same okay um also in and this is + + align:start position:0% +are the same okay um also in and this is + + + align:start position:0% +are the same okay um also in and this is +important the wave function picks up a + + align:start position:0% +important the wave function picks up a + + + align:start position:0% +important the wave function picks up a +phase if you go by by the periodicity of + + align:start position:0% +phase if you go by by the periodicity of + + + align:start position:0% +phase if you go by by the periodicity of +the real space lce but if I increase K + + align:start position:0% +the real space lce but if I increase K + + + align:start position:0% +the real space lce but if I increase K +if I add a an inverse lattice Vector to + + align:start position:0% +if I add a an inverse lattice Vector to + + + align:start position:0% +if I add a an inverse lattice Vector to +k then they're they they're exactly the + + align:start position:0% +k then they're they they're exactly the + + + align:start position:0% +k then they're they they're exactly the +same so in k space I can also translate + + align:start position:0% +same so in k space I can also translate + + + align:start position:0% +same so in k space I can also translate +around okay and the energies are the + + align:start position:0% +around okay and the energies are the + + + align:start position:0% +around okay and the energies are the +same we're going somewhere here + + align:start position:0% +same we're going somewhere here + + + align:start position:0% +same we're going somewhere here +okay we're going somewhere give me a + + align:start position:0% +okay we're going somewhere give me a + + + align:start position:0% +okay we're going somewhere give me a +minute and then I showed you this and + + align:start position:0% +minute and then I showed you this and + + + align:start position:0% +minute and then I showed you this and +does anybody have questions about this + + align:start position:0% +does anybody have questions about this + + + align:start position:0% +does anybody have questions about this +the parallel here I think is pretty + + align:start position:0% +the parallel here I think is pretty + + + align:start position:0% +the parallel here I think is pretty +self-explanatory + + align:start position:0% +self-explanatory + + + align:start position:0% +self-explanatory +right in the hydrogen + + align:start position:0% +right in the hydrogen + + + align:start position:0% +right in the hydrogen +atom we impose this spherical Symmetry + + align:start position:0% +atom we impose this spherical Symmetry + + + align:start position:0% +atom we impose this spherical Symmetry +gunti and we got out of that + + align:start position:0% +gunti and we got out of that + + + align:start position:0% +gunti and we got out of that +quantization we solved and here we + + align:start position:0% +quantization we solved and here we + + + align:start position:0% +quantization we solved and here we +impose the translational Symmetry and we + + align:start position:0% +impose the translational Symmetry and we + + + align:start position:0% +impose the translational Symmetry and we +get out of that K + + align:start position:0% +get out of that K + + + align:start position:0% +get out of that K +vectorization we but K is not a Quant k + + align:start position:0% +vectorization we but K is not a Quant k + + + align:start position:0% +vectorization we but K is not a Quant k +is a quantum number but it can be + + align:start position:0% +is a quantum number but it can be + + + align:start position:0% +is a quantum number but it can be +continuous it can be continuous okay and + + align:start position:0% +continuous it can be continuous okay and + + + align:start position:0% +continuous it can be continuous okay and +and you look at it in the first bran + + align:start position:0% +and you look at it in the first bran + + + align:start position:0% +and you look at it in the first bran +zone now somebody tell me given + + align:start position:0% + + + + align:start position:0% + +this why would I worry about K + + align:start position:0% +this why would I worry about K + + + align:start position:0% +this why would I worry about K +only no + + align:start position:0% + + + + align:start position:0% + +problem + + align:start position:0% +problem + + + align:start position:0% +problem +oh okay so I should stop like kind + + align:start position:0% +oh okay so I should stop like kind + + + align:start position:0% +oh okay so I should stop like kind +of all right uh that wrap kind of got me + + align:start position:0% +of all right uh that wrap kind of got me + + + align:start position:0% +of all right uh that wrap kind of got me +a little bit excited so uh let's go back + + align:start position:0% +a little bit excited so uh let's go back + + + align:start position:0% +a little bit excited so uh let's go back +to slide one + + align:start position:0% +to slide one + + + align:start position:0% +to slide one +okay + + align:start position:0% +okay + + + align:start position:0% +okay +um so I'm adding a an inverse lattice + + align:start position:0% +um so I'm adding a an inverse lattice + + + align:start position:0% +um so I'm adding a an inverse lattice +Vector a full Vector that gets me to + + align:start position:0% +Vector a full Vector that gets me to + + + align:start position:0% +Vector a full Vector that gets me to +another lce point in inverse space and I + + align:start position:0% +another lce point in inverse space and I + + + align:start position:0% +another lce point in inverse space and I +say my wave function is the same okay + + align:start position:0% +say my wave function is the same okay + + + align:start position:0% +say my wave function is the same okay +now why is it I also defin a bran + + align:start position:0% +now why is it I also defin a bran + + + align:start position:0% +now why is it I also defin a bran +zone right um and you can see my + + align:start position:0% +zone right um and you can see my + + + align:start position:0% +zone right um and you can see my +definition of the one zone is in fact + + align:start position:0% +definition of the one zone is in fact + + + align:start position:0% +definition of the one zone is in fact +that it's a zone that you know it's a + + align:start position:0% +that it's a zone that you know it's a + + + align:start position:0% +that it's a zone that you know it's a +lattice Vector you see those are lce + + align:start position:0% +lattice Vector you see those are lce + + + align:start position:0% +lattice Vector you see those are lce +vectors why is it that I only now care + + align:start position:0% +vectors why is it that I only now care + + + align:start position:0% +vectors why is it that I only now care +about the variation of K within that + + align:start position:0% +about the variation of K within that + + + align:start position:0% +about the variation of K within that +first bran Zone yeah + + align:start position:0% +first bran Zone yeah + + + align:start position:0% +first bran Zone yeah +same the same right that's why we care + + align:start position:0% +same the same right that's why we care + + + align:start position:0% +same the same right that's why we care +so much about that bruan zone what is it + + align:start position:0% +so much about that bruan zone what is it + + + align:start position:0% +so much about that bruan zone what is it +well it's the boundaries of the + + align:start position:0% +well it's the boundaries of the + + + align:start position:0% +well it's the boundaries of the +variability of the wave + + align:start position:0% +variability of the wave + + + align:start position:0% +variability of the wave +function in so in in in terms of how it + + align:start position:0% +function in so in in in terms of how it + + + align:start position:0% +function in so in in in terms of how it +depends on K so I only need to vary K in + + align:start position:0% +depends on K so I only need to vary K in + + + align:start position:0% +depends on K so I only need to vary K in +this first Zone but I do need to vary it + + align:start position:0% +this first Zone but I do need to vary it + + + align:start position:0% +this first Zone but I do need to vary it +in that zone I have to vary it in that + + align:start position:0% +in that zone I have to vary it in that + + + align:start position:0% +in that zone I have to vary it in that +zone because there will be variation if + + align:start position:0% +zone because there will be variation if + + + align:start position:0% +zone because there will be variation if +it's a + + align:start position:0% +it's a + + + align:start position:0% +it's a +solid okay but if I vary it and I go out + + align:start position:0% +solid okay but if I vary it and I go out + + + align:start position:0% +solid okay but if I vary it and I go out +here well you know it's just I can + + align:start position:0% +here well you know it's just I can + + + align:start position:0% +here well you know it's just I can +translate it back and it's the same + + align:start position:0% +translate it back and it's the same + + + align:start position:0% +translate it back and it's the same +thing you see so I need to I need to + + align:start position:0% +thing you see so I need to I need to + + + align:start position:0% +thing you see so I need to I need to +move K around in this first + + align:start position:0% +move K around in this first + + + align:start position:0% +move K around in this first +Zone and when I do and this is a slide + + align:start position:0% +Zone and when I do and this is a slide + + + align:start position:0% +Zone and when I do and this is a slide +I've showed before when I do what you + + align:start position:0% +I've showed before when I do what you + + + align:start position:0% +I've showed before when I do what you +get is as you go as you think about a + + align:start position:0% +get is as you go as you think about a + + + align:start position:0% +get is as you go as you think about a +system going from atoms to molecules to + + align:start position:0% +system going from atoms to molecules to + + + align:start position:0% +system going from atoms to molecules to +bands in your solid you see this is the + + align:start position:0% +bands in your solid you see this is the + + + align:start position:0% +bands in your solid you see this is the +energy of that band it Wiggles that's + + align:start position:0% +energy of that band it Wiggles that's + + + align:start position:0% +energy of that band it Wiggles that's +what happens in that first Zone you have + + align:start position:0% +what happens in that first Zone you have + + + align:start position:0% +what happens in that first Zone you have +a new quantum number you change it and + + align:start position:0% +a new quantum number you change it and + + + align:start position:0% +a new quantum number you change it and +you vary the energy right it Wiggles so + + align:start position:0% +you vary the energy right it Wiggles so + + + align:start position:0% +you vary the energy right it Wiggles so +now these orbitals are Wiggly okay + + align:start position:0% +now these orbitals are Wiggly okay + + + align:start position:0% +now these orbitals are Wiggly okay +that's the the big the most important + + align:start position:0% +that's the the big the most important + + + align:start position:0% +that's the the big the most important +thing and you can see here so here's my + + align:start position:0% +thing and you can see here so here's my + + + align:start position:0% +thing and you can see here so here's my +k space right and I can vary KX KY KZ if + + align:start position:0% +k space right and I can vary KX KY KZ if + + + align:start position:0% +k space right and I can vary KX KY KZ if +it's threedimensional + + align:start position:0% +it's threedimensional + + + align:start position:0% +it's threedimensional +solid and at each point in k space + + align:start position:0% +solid and at each point in k space + + + align:start position:0% +solid and at each point in k space +you're going to get a set of + + align:start position:0% +you're going to get a set of + + + align:start position:0% +you're going to get a set of +levels right just like you did for that + + align:start position:0% +levels right just like you did for that + + + align:start position:0% +levels right just like you did for that +atom or molecule you're going to get a + + align:start position:0% +atom or molecule you're going to get a + + + align:start position:0% +atom or molecule you're going to get a +set of levels and they they will vary + + align:start position:0% +set of levels and they they will vary + + + align:start position:0% +set of levels and they they will vary +but they will be the + + align:start position:0% +but they will be the + + + align:start position:0% +but they will be the +same if I translate by the um inverse + + align:start position:0% +same if I translate by the um inverse + + + align:start position:0% +same if I translate by the um inverse +lce Vector so if I go from here out some + + align:start position:0% +lce Vector so if I go from here out some + + + align:start position:0% +lce Vector so if I go from here out some +G Vector then I get exactly the same + + align:start position:0% +G Vector then I get exactly the same + + + align:start position:0% +G Vector then I get exactly the same +levels but if I'm inside this BR one + + align:start position:0% +levels but if I'm inside this BR one + + + align:start position:0% +levels but if I'm inside this BR one +zone they're going to vary + + align:start position:0% +zone they're going to vary + + + align:start position:0% +zone they're going to vary +okay right any questions kpace is really + + align:start position:0% +okay right any questions kpace is really + + + align:start position:0% +okay right any questions kpace is really +important for + + align:start position:0% + + + + align:start position:0% + +solids okay and so what do we do well so + + align:start position:0% +solids okay and so what do we do well so + + + align:start position:0% +solids okay and so what do we do well so +the inverse lattice you know it's + + align:start position:0% +the inverse lattice you know it's + + + align:start position:0% +the inverse lattice you know it's +related to the real space lattice if I + + align:start position:0% +related to the real space lattice if I + + + align:start position:0% +related to the real space lattice if I +double the real space + + align:start position:0% +double the real space + + + align:start position:0% +double the real space +lattice so it's periodic but with more + + align:start position:0% +lattice so it's periodic but with more + + + align:start position:0% +lattice so it's periodic but with more +atoms in the cell right so it's periodic + + align:start position:0% +atoms in the cell right so it's periodic + + + align:start position:0% +atoms in the cell right so it's periodic +over a larger domain then basically I'm + + align:start position:0% +over a larger domain then basically I'm + + + align:start position:0% +over a larger domain then basically I'm +change you know it's it's like a forier + + align:start position:0% +change you know it's it's like a forier + + + align:start position:0% +change you know it's it's like a forier +series right so if I go to larger real + + align:start position:0% +series right so if I go to larger real + + + align:start position:0% +series right so if I go to larger real +space lattice then I have finer and + + align:start position:0% +space lattice then I have finer and + + + align:start position:0% +space lattice then I have finer and +finer k + + align:start position:0% +finer k + + + align:start position:0% +finer k +space right and so what that means is + + align:start position:0% +space right and so what that means is + + + align:start position:0% +space right and so what that means is +that you know you you can choose a + + align:start position:0% +that you know you you can choose a + + + align:start position:0% +that you know you you can choose a +certain K mesh this is a variable in the + + align:start position:0% +certain K mesh this is a variable in the + + + align:start position:0% +certain K mesh this is a variable in the +input now for solids for solids this is + + align:start position:0% +input now for solids for solids this is + + + align:start position:0% +input now for solids for solids this is +a new critical variable in your + + align:start position:0% +a new critical variable in your + + + align:start position:0% +a new critical variable in your +calculations okay of solids you need a k + + align:start position:0% +calculations okay of solids you need a k + + + align:start position:0% +calculations okay of solids you need a k +mesh and this is just a number you'll + + align:start position:0% +mesh and this is just a number you'll + + + align:start position:0% +mesh and this is just a number you'll +enter eight or two or four and it'll + + align:start position:0% +enter eight or two or four and it'll + + + align:start position:0% +enter eight or two or four and it'll +just do a cube because it's simple but + + align:start position:0% +just do a cube because it's simple but + + + align:start position:0% +just do a cube because it's simple but +you don't have to do a cube but the code + + align:start position:0% +you don't have to do a cube but the code + + + align:start position:0% +you don't have to do a cube but the code +does a cube on the nanohub so if I enter + + align:start position:0% +does a cube on the nanohub so if I enter + + + align:start position:0% +does a cube on the nanohub so if I enter +8 by 8 by 8 I get 512k points on the + + align:start position:0% +8 by 8 by 8 I get 512k points on the + + + align:start position:0% +8 by 8 by 8 I get 512k points on the +mesh and what that does is it allows me + + align:start position:0% +mesh and what that does is it allows me + + + align:start position:0% +mesh and what that does is it allows me +to um it it is it + + align:start position:0% +to um it it is it + + + align:start position:0% +to um it it is it +effectively is like increasing how much + + align:start position:0% +effectively is like increasing how much + + + align:start position:0% +effectively is like increasing how much +real space I had right because they're + + align:start position:0% +real space I had right because they're + + + align:start position:0% +real space I had right because they're +they're related if I had a larger unit + + align:start position:0% +they're related if I had a larger unit + + + align:start position:0% +they're related if I had a larger unit +cell with more real space I'd have finer + + align:start position:0% +cell with more real space I'd have finer + + + align:start position:0% +cell with more real space I'd have finer +finer uh um Cas space and and so you can + + align:start position:0% +finer uh um Cas space and and so you can + + + align:start position:0% +finer uh um Cas space and and so you can +think about these things as being able + + align:start position:0% +think about these things as being able + + + align:start position:0% +think about these things as being able +to go back and + + align:start position:0% +to go back and + + + align:start position:0% +to go back and +forth + + align:start position:0% +forth + + + align:start position:0% +forth +right okay now the reason that you don't + + align:start position:0% +right okay now the reason that you don't + + + align:start position:0% +right okay now the reason that you don't +go to and now oh well how many k points + + align:start position:0% +go to and now oh well how many k points + + + align:start position:0% +go to and now oh well how many k points +do you need well you need to have enough + + align:start position:0% +do you need well you need to have enough + + + align:start position:0% +do you need well you need to have enough +K points you need to distribute K points + + align:start position:0% +K points you need to distribute K points + + + align:start position:0% +K points you need to distribute K points +in your bran Zone such that what what's + + align:start position:0% +in your bran Zone such that what what's + + + align:start position:0% +in your bran Zone such that what what's +the answer how many k points do I need + + align:start position:0% +the answer how many k points do I need + + + align:start position:0% +the answer how many k points do I need +it's my favorite answer + + align:start position:0% +it's my favorite answer + + + align:start position:0% +it's my favorite answer +depends it + + align:start position:0% +depends it + + + align:start position:0% +depends it +depends what does it depend on did that + + align:start position:0% +depends what does it depend on did that + + + align:start position:0% +depends what does it depend on did that +come from the back I love it what does + + align:start position:0% +come from the back I love it what does + + + align:start position:0% +come from the back I love it what does +it depend + + align:start position:0% + + + + align:start position:0% + +on okay it might depend on the + + align:start position:0% +on okay it might depend on the + + + align:start position:0% +on okay it might depend on the +electrons what else might it depend on + + align:start position:0% +electrons what else might it depend on + + + align:start position:0% +electrons what else might it depend on +how many k points do I + + align:start position:0% +how many k points do I + + + align:start position:0% +how many k points do I +need okay yes yes look at this picture + + align:start position:0% +need okay yes yes look at this picture + + + align:start position:0% +need okay yes yes look at this picture +let's look back at this picture think + + align:start position:0% +let's look back at this picture think + + + align:start position:0% +let's look back at this picture think +about this and now try to think about + + align:start position:0% +about this and now try to think about + + + align:start position:0% +about this and now try to think about +how many k points do I + + align:start position:0% + + + + align:start position:0% + +needu exactly I need enough right now + + align:start position:0% +needu exactly I need enough right now + + + align:start position:0% +needu exactly I need enough right now +what's enough well enough so that you + + align:start position:0% +what's enough well enough so that you + + + align:start position:0% +what's enough well enough so that you +can + + align:start position:0% +can + + + align:start position:0% +can +resolve how the energy is going to + + align:start position:0% +resolve how the energy is going to + + + align:start position:0% +resolve how the energy is going to +change + + align:start position:0% +change + + + align:start position:0% +change +okay so now tell me if the Wiggles + + align:start position:0% +okay so now tell me if the Wiggles + + + align:start position:0% +okay so now tell me if the Wiggles +are are slow and not so much right + + align:start position:0% +are are slow and not so much right + + + align:start position:0% +are are slow and not so much right +if the Wiggles are like this or maybe + + align:start position:0% +if the Wiggles are like this or maybe + + + align:start position:0% +if the Wiggles are like this or maybe +even they're really flat do I need a lot + + align:start position:0% +even they're really flat do I need a lot + + + align:start position:0% +even they're really flat do I need a lot +of K points or a little bit of K + + align:start position:0% +of K points or a little bit of K + + + align:start position:0% +of K points or a little bit of K +points how many a + + align:start position:0% +points how many a + + + align:start position:0% +points how many a +lot just a little bit because there's + + align:start position:0% +lot just a little bit because there's + + + align:start position:0% +lot just a little bit because there's +just not that much variation but if the + + align:start position:0% +just not that much variation but if the + + + align:start position:0% +just not that much variation but if the +Wiggles look like + + align:start position:0% +Wiggles look like + + + align:start position:0% +Wiggles look like +this would I need a lot or a little + + align:start position:0% +this would I need a lot or a little + + + align:start position:0% +this would I need a lot or a little +right and and so this is the behavior of + + align:start position:0% +right and and so this is the behavior of + + + align:start position:0% +right and and so this is the behavior of +of bands that look like this are more + + align:start position:0% +of bands that look like this are more + + + align:start position:0% +of bands that look like this are more +sort of + + align:start position:0% +sort of + + + align:start position:0% +sort of +metallicy okay and the behavior of bands + + align:start position:0% +metallicy okay and the behavior of bands + + + align:start position:0% +metallicy okay and the behavior of bands +that look like this the the flat ones + + align:start position:0% +that look like this the the flat ones + + + align:start position:0% +that look like this the the flat ones +are more kind of like insulator + + align:start position:0% +are more kind of like insulator + + + align:start position:0% +are more kind of like insulator +e okay and in between and we'll see on + + align:start position:0% +e okay and in between and we'll see on + + + align:start position:0% +e okay and in between and we'll see on +Thursday we'll talk about how you can + + align:start position:0% +Thursday we'll talk about how you can + + + align:start position:0% +Thursday we'll talk about how you can +actually calculate the mobility from + + align:start position:0% +actually calculate the mobility from + + + align:start position:0% +actually calculate the mobility from +these bands from this wiggle okay um and + + align:start position:0% +these bands from this wiggle okay um and + + + align:start position:0% +these bands from this wiggle okay um and +but you can um how many do you need well + + align:start position:0% +but you can um how many do you need well + + + align:start position:0% +but you can um how many do you need well +it depends it depends on the nature of + + align:start position:0% +it depends it depends on the nature of + + + align:start position:0% +it depends it depends on the nature of +the material but you have to converge + + align:start position:0% +the material but you have to converge + + + align:start position:0% +the material but you have to converge +that that's part of that responsibility + + align:start position:0% +that that's part of that responsibility + + + align:start position:0% +that that's part of that responsibility +Spider-Man's Uncle knew all about it + + align:start position:0% +Spider-Man's Uncle knew all about it + + + align:start position:0% +Spider-Man's Uncle knew all about it +okay and so this is sort of where we + + align:start position:0% +okay and so this is sort of where we + + + align:start position:0% +okay and so this is sort of where we +ended + + align:start position:0% +ended + + + align:start position:0% +ended +oh man come on there we go this is where + + align:start position:0% +oh man come on there we go this is where + + + align:start position:0% +oh man come on there we go this is where +we ended and you know so you have energy + + align:start position:0% +we ended and you know so you have energy + + + align:start position:0% +we ended and you know so you have energy +levels in the bran Zone um K is a + + align:start position:0% +levels in the bran Zone um K is a + + + align:start position:0% +levels in the bran Zone um K is a +continuous variable but you don't + + align:start position:0% +continuous variable but you don't + + + align:start position:0% +continuous variable but you don't +actually continue it everywhere because + + align:start position:0% +actually continue it everywhere because + + + align:start position:0% +actually continue it everywhere because +it's too hard so you just do what the + + align:start position:0% +it's too hard so you just do what the + + + align:start position:0% +it's too hard so you just do what the +computer does is a bunch of calculations + + align:start position:0% +computer does is a bunch of calculations + + + align:start position:0% +computer does is a bunch of calculations +at different K points on the grid you + + align:start position:0% +at different K points on the grid you + + + align:start position:0% +at different K points on the grid you +give it okay um and what you're doing + + align:start position:0% +give it okay um and what you're doing + + + align:start position:0% +give it okay um and what you're doing +then is you're moving through when you + + align:start position:0% +then is you're moving through when you + + + align:start position:0% +then is you're moving through when you +give it different cas points literally + + align:start position:0% +give it different cas points literally + + + align:start position:0% +give it different cas points literally +this is what you do you say compute the + + align:start position:0% +this is what you do you say compute the + + + align:start position:0% +this is what you do you say compute the +the what what the computer is doing is + + align:start position:0% +the what what the computer is doing is + + + align:start position:0% +the what what the computer is doing is +it's saying compute the energy levels at + + align:start position:0% +it's saying compute the energy levels at + + + align:start position:0% +it's saying compute the energy levels at +k. now compute the energy levels at K + + align:start position:0% +k. now compute the energy levels at K + + + align:start position:0% +k. now compute the energy levels at K +point you know uh. + + align:start position:0% +point you know uh. + + + align:start position:0% +point you know uh. +1.1.1 right and you literally just give + + align:start position:0% +1.1.1 right and you literally just give + + + align:start position:0% +1.1.1 right and you literally just give +it coordinates of K points within the + + align:start position:0% +it coordinates of K points within the + + + align:start position:0% +it coordinates of K points within the +Broan Zone and for each of those K + + align:start position:0% +Broan Zone and for each of those K + + + align:start position:0% +Broan Zone and for each of those K +points it does the calculations and it + + align:start position:0% +points it does the calculations and it + + + align:start position:0% +points it does the calculations and it +finds a set of energy levels which are + + align:start position:0% +finds a set of energy levels which are + + + align:start position:0% +finds a set of energy levels which are +different and those and then you fill + + align:start position:0% +different and those and then you fill + + + align:start position:0% +different and those and then you fill +that in and you get your curvy bands + + align:start position:0% +that in and you get your curvy bands + + + align:start position:0% +that in and you get your curvy bands +okay who's with me who's who's got + + align:start position:0% +okay who's with me who's who's got + + + align:start position:0% +okay who's with me who's who's got +questions anyone have + + align:start position:0% +questions anyone have + + + align:start position:0% +questions anyone have +questions that's the new yeah so each is + + align:start position:0% +questions that's the new yeah so each is + + + align:start position:0% +questions that's the new yeah so each is +a distinct number of energy + + align:start position:0% +a distinct number of energy + + + align:start position:0% +a distinct number of energy +states yeah well each K point is the + + align:start position:0% +states yeah well each K point is the + + + align:start position:0% +states yeah well each K point is the +same number of of energy states but they + + align:start position:0% +same number of of energy states but they + + + align:start position:0% +same number of of energy states but they +can move + + align:start position:0% +can move + + + align:start position:0% +can move +around depending on where you are in + + align:start position:0% +around depending on where you are in + + + align:start position:0% +around depending on where you are in +that BR one zone okay and their moving + + align:start position:0% +that BR one zone okay and their moving + + + align:start position:0% +that BR one zone okay and their moving +around this is what gives you the band + + align:start position:0% +around this is what gives you the band + + + align:start position:0% +around this is what gives you the band +structure + + align:start position:0% +structure + + + align:start position:0% +structure +um so you know in the code and and this + + align:start position:0% +um so you know in the code and and this + + + align:start position:0% +um so you know in the code and and this +on the previous slide I didn't talk + + align:start position:0% +on the previous slide I didn't talk + + + align:start position:0% +on the previous slide I didn't talk +about it was the second point but on the + + align:start position:0% +about it was the second point but on the + + + align:start position:0% +about it was the second point but on the +code you you know each one of these you + + align:start position:0% +code you you know each one of these you + + + align:start position:0% +code you you know each one of these you +can think of as sort of occupied by + + align:start position:0% +can think of as sort of occupied by + + + align:start position:0% +can think of as sort of occupied by +electrons okay because it's it's sort of + + align:start position:0% +electrons okay because it's it's sort of + + + align:start position:0% +electrons okay because it's it's sort of +looking at this K point right and then + + align:start position:0% +looking at this K point right and then + + + align:start position:0% +looking at this K point right and then +this K Point um but when you think about + + align:start position:0% +this K Point um but when you think about + + + align:start position:0% +this K Point um but when you think about +the full band structure of a material + + align:start position:0% +the full band structure of a material + + + align:start position:0% +the full band structure of a material +that is not how you look at it right do + + align:start position:0% +that is not how you look at it right do + + + align:start position:0% +that is not how you look at it right do +you don't have you know you would to + + align:start position:0% +you don't have you know you would to + + + align:start position:0% +you don't have you know you would to +keep increasing your cap mes you would + + align:start position:0% +keep increasing your cap mes you would + + + align:start position:0% +keep increasing your cap mes you would +have infinite number of electrons in a + + align:start position:0% +have infinite number of electrons in a + + + align:start position:0% +have infinite number of electrons in a +band um that is not the case what you + + align:start position:0% +band um that is not the case what you + + + align:start position:0% +band um that is not the case what you +have is the same as before the same + + align:start position:0% +have is the same as before the same + + + align:start position:0% +have is the same as before the same +exact thing as you know molecular states + + align:start position:0% +exact thing as you know molecular states + + + align:start position:0% +exact thing as you know molecular states +which is that you can have one band can + + align:start position:0% +which is that you can have one band can + + + align:start position:0% +which is that you can have one band can +hold two electrons one up one down + + align:start position:0% +hold two electrons one up one down + + + align:start position:0% +hold two electrons one up one down +that's exactly the same as as in you + + align:start position:0% +that's exactly the same as as in you + + + align:start position:0% +that's exactly the same as as in you +know a molecular + + align:start position:0% +know a molecular + + + align:start position:0% +know a molecular +State + + align:start position:0% + + + + align:start position:0% + +okay but depending on where you are in + + align:start position:0% +okay but depending on where you are in + + + align:start position:0% +okay but depending on where you are in +the bruan zone the energy of that that + + align:start position:0% +the bruan zone the energy of that that + + + align:start position:0% +the bruan zone the energy of that that +band now can change dramatically and + + align:start position:0% +band now can change dramatically and + + + align:start position:0% +band now can change dramatically and +that changes everything in terms of + + align:start position:0% +that changes everything in terms of + + + align:start position:0% +that changes everything in terms of +properties of material in particular + + align:start position:0% +properties of material in particular + + + align:start position:0% +properties of material in particular +what we're focusing on here is Optical + + align:start position:0% +what we're focusing on here is Optical + + + align:start position:0% +what we're focusing on here is Optical +properties in electronic properties + + align:start position:0% +properties in electronic properties + + + align:start position:0% +properties in electronic properties +because those are very Quantum + + align:start position:0% +because those are very Quantum + + + align:start position:0% +because those are very Quantum +mechanically which we like okay now and + + align:start position:0% +mechanically which we like okay now and + + + align:start position:0% +mechanically which we like okay now and +the firmy energy is um in in the code + + align:start position:0% +the firmy energy is um in in the code + + + align:start position:0% +the firmy energy is um in in the code +the we talked about the firmy energy a + + align:start position:0% +the we talked about the firmy energy a + + + align:start position:0% +the we talked about the firmy energy a +little bit for molecules um it's sort of + + align:start position:0% +little bit for molecules um it's sort of + + + align:start position:0% +little bit for molecules um it's sort of +the energy at which you stop filling + + align:start position:0% +the energy at which you stop filling + + + align:start position:0% +the energy at which you stop filling +right it's it's the energy so you you + + align:start position:0% +right it's it's the energy so you you + + + align:start position:0% +right it's it's the energy so you you +fill your bands up to the fir you can + + align:start position:0% +fill your bands up to the fir you can + + + align:start position:0% +fill your bands up to the fir you can +just think about it that way okay don't + + align:start position:0% +just think about it that way okay don't + + + align:start position:0% +just think about it that way okay don't +worry about so much about whether it's + + align:start position:0% +worry about so much about whether it's + + + align:start position:0% +worry about so much about whether it's +in the gap or where it is in the Gap we + + align:start position:0% +in the gap or where it is in the Gap we + + + align:start position:0% +in the gap or where it is in the Gap we +don't need to worry about that in this + + align:start position:0% +don't need to worry about that in this + + + align:start position:0% +don't need to worry about that in this +class okay but it is the energy at where + + align:start position:0% +class okay but it is the energy at where + + + align:start position:0% +class okay but it is the energy at where +at which you stop filling and so you can + + align:start position:0% +at which you stop filling and so you can + + + align:start position:0% +at which you stop filling and so you can +see that um if you oh I have some + + align:start position:0% +see that um if you oh I have some + + + align:start position:0% +see that um if you oh I have some +properties I thought I had something + + align:start position:0% +properties I thought I had something + + + align:start position:0% +properties I thought I had something +else but if + + align:start position:0% +else but if + + + align:start position:0% +else but if +you if you were to um fill + + align:start position:0% +you if you were to um fill + + + align:start position:0% +you if you were to um fill +these and the bands and and these bands + + align:start position:0% +these and the bands and and these bands + + + align:start position:0% +these and the bands and and these bands +didn't stop nicely like this but they + + align:start position:0% +didn't stop nicely like this but they + + + align:start position:0% +didn't stop nicely like this but they +just kind of crossed over it what would + + align:start position:0% +just kind of crossed over it what would + + + align:start position:0% +just kind of crossed over it what would +you have what kind of material would you + + align:start position:0% + + + + align:start position:0% + +have + + align:start position:0% +have + + + align:start position:0% +have +yeah it's a + + align:start position:0% +yeah it's a + + + align:start position:0% +yeah it's a +metal it's a metal right and if you if + + align:start position:0% +metal it's a metal right and if you if + + + align:start position:0% +metal it's a metal right and if you if +you have the bands stop where you stop + + align:start position:0% +you have the bands stop where you stop + + + align:start position:0% +you have the bands stop where you stop +filling and then there's a gap it's a + + align:start position:0% +filling and then there's a gap it's a + + + align:start position:0% +filling and then there's a gap it's a +semiconductor or an insulator okay + + align:start position:0% + + + + align:start position:0% + +um let's do a few + + align:start position:0% +um let's do a few + + + align:start position:0% +um let's do a few +calculations um and then I'll come back + + align:start position:0% +calculations um and then I'll come back + + + align:start position:0% +calculations um and then I'll come back +to structural properties okay we are on + + align:start position:0% +to structural properties okay we are on + + + align:start position:0% +to structural properties okay we are on +our favorite + + align:start position:0% +our favorite + + + align:start position:0% +our favorite +place the Hub of + + align:start position:0% +place the Hub of + + + align:start position:0% +place the Hub of +Nano right yeah okay come + + align:start position:0% +Nano right yeah okay come + + + align:start position:0% +Nano right yeah okay come +on yes okay we got to that + + align:start position:0% +on yes okay we got to that + + + align:start position:0% +on yes okay we got to that +stage launch Tool sounds like a good + + align:start position:0% +stage launch Tool sounds like a good + + + align:start position:0% +stage launch Tool sounds like a good +idea and + + align:start position:0% +idea and + + + align:start position:0% +idea and +this is where we we had some issues last + + align:start position:0% +this is where we we had some issues last + + + align:start position:0% +this is where we we had some issues last +time not going to kid you there it is + + align:start position:0% +time not going to kid you there it is + + + align:start position:0% +time not going to kid you there it is +okay and we go to here now let's do a + + align:start position:0% +okay and we go to here now let's do a + + + align:start position:0% +okay and we go to here now let's do a +few things + + align:start position:0% +few things + + + align:start position:0% +few things +okay um + + align:start position:0% +okay um + + + align:start position:0% +okay um +and okay so this is the same as okay so + + align:start position:0% +and okay so this is the same as okay so + + + align:start position:0% +and okay so this is the same as okay so +it's not letting me scroll again that's + + align:start position:0% +it's not letting me scroll again that's + + + align:start position:0% +it's not letting me scroll again that's +wonderful + + align:start position:0% +wonderful + + + align:start position:0% +wonderful +right + + align:start position:0% + + + + align:start position:0% + +um there it is okay now um this is the + + align:start position:0% +um there it is okay now um this is the + + + align:start position:0% +um there it is okay now um this is the +same as um as the tool that you're using + + align:start position:0% +same as um as the tool that you're using + + + align:start position:0% +same as um as the tool that you're using +for um for the homework number two okay + + align:start position:0% +for um for the homework number two okay + + + align:start position:0% +for um for the homework number two okay +to look at molecules and in looking at + + align:start position:0% +to look at molecules and in looking at + + + align:start position:0% +to look at molecules and in looking at +molecules you just select + + align:start position:0% +molecules you just select + + + align:start position:0% +molecules you just select +molecule but all the code is doing when + + align:start position:0% +molecule but all the code is doing when + + + align:start position:0% +molecule but all the code is doing when +you look at molecules you know all the + + align:start position:0% +you look at molecules you know all the + + + align:start position:0% +you look at molecules you know all the +code is doing is it's saying well + + align:start position:0% +code is doing is it's saying well + + + align:start position:0% +code is doing is it's saying well +whatever you give me you know whatever + + align:start position:0% +whatever you give me you know whatever + + + align:start position:0% +whatever you give me you know whatever +sort of thing you give me I'm G to put + + align:start position:0% +sort of thing you give me I'm G to put + + + align:start position:0% +sort of thing you give me I'm G to put +space in my you know in my periodic + + align:start position:0% + + + + align:start position:0% + +cell I'm G to put enough space so that + + align:start position:0% +cell I'm G to put enough space so that + + + align:start position:0% +cell I'm G to put enough space so that +it doesn't see its own + + align:start position:0% + + + + align:start position:0% + +image okay that's all it's doing it's + + align:start position:0% +image okay that's all it's doing it's + + + align:start position:0% +image okay that's all it's doing it's +still a periodic calculation it's just + + align:start position:0% +still a periodic calculation it's just + + + align:start position:0% +still a periodic calculation it's just +putting a whole bunch of space in there + + align:start position:0% +putting a whole bunch of space in there + + + align:start position:0% +putting a whole bunch of space in there +um you could choose solid and do + + align:start position:0% +um you could choose solid and do + + + align:start position:0% +um you could choose solid and do +molecule calculations and just make sure + + align:start position:0% +molecule calculations and just make sure + + + align:start position:0% +molecule calculations and just make sure +that that there's space between um what + + align:start position:0% +that that there's space between um what + + + align:start position:0% +that that there's space between um what +you put in + + align:start position:0% +you put in + + + align:start position:0% +you put in +okay however when you choose solid then + + align:start position:0% +okay however when you choose solid then + + + align:start position:0% +okay however when you choose solid then +um you can see that it's actually + + align:start position:0% +um you can see that it's actually + + + align:start position:0% +um you can see that it's actually +entering the coordinates in a different + + align:start position:0% +entering the coordinates in a different + + + align:start position:0% +entering the coordinates in a different +way it's using a slightly different + + align:start position:0% +way it's using a slightly different + + + align:start position:0% +way it's using a slightly different +language um has anybody seen n this + + align:start position:0% +language um has anybody seen n this + + + align:start position:0% +language um has anybody seen n this +beautiful non-scrolling + + align:start position:0% +beautiful non-scrolling + + + align:start position:0% +beautiful non-scrolling +thing + + align:start position:0% +thing + + + align:start position:0% +thing +man oh yeah well it's good to be + + align:start position:0% +man oh yeah well it's good to be + + + align:start position:0% +man oh yeah well it's good to be +challenged that's + + align:start position:0% +challenged that's + + + align:start position:0% +challenged that's +fun okay so uh + + align:start position:0% +fun okay so uh + + + align:start position:0% +fun okay so uh +you gota be kidding + + align:start position:0% +you gota be kidding + + + align:start position:0% +you gota be kidding +me did you see that coming did somebody + + align:start position:0% +me did you see that coming did somebody + + + align:start position:0% +me did you see that coming did somebody +see that + + align:start position:0% +see that + + + align:start position:0% +see that +coming all right should we go back to + + align:start position:0% +coming all right should we go back to + + + align:start position:0% +coming all right should we go back to +the uh to DJ Dave wait + + align:start position:0% +the uh to DJ Dave wait + + + align:start position:0% +the uh to DJ Dave wait +um what if I did um + + align:start position:0% + + + + align:start position:0% + +Firefox is that + + align:start position:0% +Firefox is that + + + align:start position:0% +Firefox is that +better it's the same that's beautiful + + align:start position:0% +better it's the same that's beautiful + + + align:start position:0% +better it's the same that's beautiful +you get the same thing + + align:start position:0% + + + + align:start position:0% + +okay it did remember me okay now let's + + align:start position:0% +okay it did remember me okay now let's + + + align:start position:0% +okay it did remember me okay now let's +close + + align:start position:0% +close + + + align:start position:0% +close +that how often does that + + align:start position:0% + + + + align:start position:0% + +happen but like what percentage would + + align:start position:0% +happen but like what percentage would + + + align:start position:0% +happen but like what percentage would +you + + align:start position:0% + + + + align:start position:0% + +say 60% of the + + align:start position:0% +say 60% of the + + + align:start position:0% +say 60% of the +time + + align:start position:0% + + + + align:start position:0% + +60 oh no no no you can't be this on a + + align:start position:0% +60 oh no no no you can't be this on a + + + align:start position:0% +60 oh no no no you can't be this on a +Mac this is because it's not a Mac okay + + align:start position:0% +Mac this is because it's not a Mac okay + + + align:start position:0% +Mac this is because it's not a Mac okay +thank you it must + + align:start position:0% + + + + align:start position:0% + +be + + align:start position:0% +be + + + align:start position:0% +be +Windows well that's a big + + align:start position:0% +Windows well that's a big + + + align:start position:0% +Windows well that's a big +problem um okay so here we are this + + align:start position:0% +problem um okay so here we are this + + + align:start position:0% +problem um okay so here we are this +looks a little bit better now when you + + align:start position:0% +looks a little bit better now when you + + + align:start position:0% +looks a little bit better now when you +choose solid okay so now we have look at + + align:start position:0% +choose solid okay so now we have look at + + + align:start position:0% +choose solid okay so now we have look at +this you can choose your Crystal + + align:start position:0% +this you can choose your Crystal + + + align:start position:0% +this you can choose your Crystal +symmetry because it's a solid and + + align:start position:0% +symmetry because it's a solid and + + + align:start position:0% +symmetry because it's a solid and +remember those symmetries that you saw + + align:start position:0% +remember those symmetries that you saw + + + align:start position:0% +remember those symmetries that you saw +well these are those symmetries except + + align:start position:0% +well these are those symmetries except + + + align:start position:0% +well these are those symmetries except +now you have to choose a lattice + + align:start position:0% +now you have to choose a lattice + + + align:start position:0% +now you have to choose a lattice +constant see when you did the molecule + + align:start position:0% +constant see when you did the molecule + + + align:start position:0% +constant see when you did the molecule +the lattice constant was simply um big + + align:start position:0% +the lattice constant was simply um big + + + align:start position:0% +the lattice constant was simply um big +it was just big so that the molecule + + align:start position:0% +it was just big so that the molecule + + + align:start position:0% +it was just big so that the molecule +didn't feel its periodic image but now + + align:start position:0% +didn't feel its periodic image but now + + + align:start position:0% +didn't feel its periodic image but now +that we're doing a solid the lattice + + align:start position:0% +that we're doing a solid the lattice + + + align:start position:0% +that we're doing a solid the lattice +constant has to be well like the lattice + + align:start position:0% +constant has to be well like the lattice + + + align:start position:0% +constant has to be well like the lattice +constant right of the material and + + align:start position:0% +constant right of the material and + + + align:start position:0% +constant right of the material and +depending on the symmetry of the + + align:start position:0% +depending on the symmetry of the + + + align:start position:0% +depending on the symmetry of the +material you know you're going to get + + align:start position:0% +material you know you're going to get + + + align:start position:0% +material you know you're going to get +different lce constants so if I um now + + align:start position:0% +different lce constants so if I um now + + + align:start position:0% +different lce constants so if I um now +and have any of you seen fractional + + align:start position:0% +and have any of you seen fractional + + + align:start position:0% +and have any of you seen fractional +coordinates before do anybody know what + + align:start position:0% +coordinates before do anybody know what + + + align:start position:0% +coordinates before do anybody know what +this is + + align:start position:0% +this is + + + align:start position:0% +this is +so so this is actually an important + + align:start position:0% +so so this is actually an important + + + align:start position:0% +so so this is actually an important +language of solids um where you know + + align:start position:0% +language of solids um where you know + + + align:start position:0% +language of solids um where you know +often times so with a solid you have a + + align:start position:0% +often times so with a solid you have a + + + align:start position:0% +often times so with a solid you have a +periodically repeating space that is set + + align:start position:0% +periodically repeating space that is set + + + align:start position:0% +periodically repeating space that is set +by a lattice constant and so often it's + + align:start position:0% +by a lattice constant and so often it's + + + align:start position:0% +by a lattice constant and so often it's +um it's sort of simpler to think about + + align:start position:0% +um it's sort of simpler to think about + + + align:start position:0% +um it's sort of simpler to think about +the coordinates that go inside that + + align:start position:0% +the coordinates that go inside that + + + align:start position:0% +the coordinates that go inside that +space the basis if you want as fractions + + align:start position:0% +space the basis if you want as fractions + + + align:start position:0% +space the basis if you want as fractions +of the + + align:start position:0% +of the + + + align:start position:0% +of the +lattice right so for silicon actually + + align:start position:0% +lattice right so for silicon actually + + + align:start position:0% +lattice right so for silicon actually +for silicon it's an FCC cryst + + align:start position:0% +for silicon it's an FCC cryst + + + align:start position:0% +for silicon it's an FCC cryst +C with a basis at one corner of the FCC + + align:start position:0% +C with a basis at one corner of the FCC + + + align:start position:0% +C with a basis at one corner of the FCC +and another atom at a quarter quarter + + align:start position:0% +and another atom at a quarter quarter + + + align:start position:0% +and another atom at a quarter quarter +quarter out in terms of the lattice this + + align:start position:0% +quarter out in terms of the lattice this + + + align:start position:0% +quarter out in terms of the lattice this +is not at a quarter quarter quarter + + align:start position:0% +is not at a quarter quarter quarter + + + align:start position:0% +is not at a quarter quarter quarter +ingstrom right this is a quarter quarter + + align:start position:0% +ingstrom right this is a quarter quarter + + + align:start position:0% +ingstrom right this is a quarter quarter +quarter scaled by that + + align:start position:0% +quarter scaled by that + + + align:start position:0% +quarter scaled by that +lattice okay does everybody see that + + align:start position:0% +lattice okay does everybody see that + + + align:start position:0% +lattice okay does everybody see that +which is a cubic face centered + + align:start position:0% +which is a cubic face centered + + + align:start position:0% +which is a cubic face centered +lattice okay so that's fractional + + align:start position:0% +lattice okay so that's fractional + + + align:start position:0% +lattice okay so that's fractional +coordinates you can go back and forth I + + align:start position:0% +coordinates you can go back and forth I + + + align:start position:0% +coordinates you can go back and forth I +mean you can you know you can write a + + align:start position:0% +mean you can you know you can write a + + + align:start position:0% +mean you can you know you can write a +10line you know python script to go back + + align:start position:0% +10line you know python script to go back + + + align:start position:0% +10line you know python script to go back +and forth between the two but in solids + + align:start position:0% +and forth between the two but in solids + + + align:start position:0% +and forth between the two but in solids +often we like to think about positions + + align:start position:0% +often we like to think about positions + + + align:start position:0% +often we like to think about positions +in terms of the symmetry of the lattice + + align:start position:0% +in terms of the symmetry of the lattice + + + align:start position:0% +in terms of the symmetry of the lattice +and so that's how we write them okay now + + align:start position:0% +and so that's how we write them okay now + + + align:start position:0% +and so that's how we write them okay now +in this case I have two silicon + + align:start position:0% +in this case I have two silicon + + + align:start position:0% +in this case I have two silicon +atoms + + align:start position:0% + + + + align:start position:0% + +and um we're going to ignore everything + + align:start position:0% +and um we're going to ignore everything + + + align:start position:0% +and um we're going to ignore everything +and just run + + align:start position:0% +and just run + + + align:start position:0% +and just run +it is that how you guys do it anyway you + + align:start position:0% +it is that how you guys do it anyway you + + + align:start position:0% +it is that how you guys do it anyway you +just like + + align:start position:0% +just like + + + align:start position:0% +just like +simulate it's fun to do that just + + align:start position:0% +simulate it's fun to do that just + + + align:start position:0% +simulate it's fun to do that just +simulate um + + align:start position:0% +simulate um + + + align:start position:0% +simulate um +except that you need to kind of know + + align:start position:0% +except that you need to kind of know + + + align:start position:0% +except that you need to kind of know +what you did um now that's what I I want + + align:start position:0% +what you did um now that's what I I want + + + align:start position:0% +what you did um now that's what I I want +to ask you about is what did I do okay + + align:start position:0% +to ask you about is what did I do okay + + + align:start position:0% +to ask you about is what did I do okay +oh look at that this is solid I only + + align:start position:0% +oh look at that this is solid I only + + + align:start position:0% +oh look at that this is solid I only +gave it two atoms and yet because it has + + align:start position:0% +gave it two atoms and yet because it has + + + align:start position:0% +gave it two atoms and yet because it has +the Symmetry and the lattice and all + + align:start position:0% +the Symmetry and the lattice and all + + + align:start position:0% +the Symmetry and the lattice and all +that it knows how to construct a solid + + align:start position:0% +that it knows how to construct a solid + + + align:start position:0% +that it knows how to construct a solid +right that's what it looks like when the + + align:start position:0% +right that's what it looks like when the + + + align:start position:0% +right that's what it looks like when the +computer thinks about it it thinks about + + align:start position:0% +computer thinks about it it thinks about + + + align:start position:0% +computer thinks about it it thinks about +it like that um uh + + align:start position:0% + + + + align:start position:0% + +oh where's the + + align:start position:0% +oh where's the + + + align:start position:0% +oh where's the +oh here we + + align:start position:0% +oh here we + + + align:start position:0% +oh here we +go now key outputs + + align:start position:0% +go now key outputs + + + align:start position:0% +go now key outputs +okay it's telling you that um it has + + align:start position:0% +okay it's telling you that um it has + + + align:start position:0% +okay it's telling you that um it has +well these should really be four um it + + align:start position:0% +well these should really be four um it + + + align:start position:0% +well these should really be four um it +has four up electrons and four down + + align:start position:0% +has four up electrons and four down + + + align:start position:0% +has four up electrons and four down +electrons okay that doesn't sound like + + align:start position:0% +electrons okay that doesn't sound like + + + align:start position:0% +electrons okay that doesn't sound like +that many electrons how come I only have + + align:start position:0% +that many electrons how come I only have + + + align:start position:0% +that many electrons how come I only have +eight electrons in my simulation and I'm + + align:start position:0% +eight electrons in my simulation and I'm + + + align:start position:0% +eight electrons in my simulation and I'm +simulating like an infinite + + align:start position:0% + + + + align:start position:0% + +Crystal yeah okay so very good but how + + align:start position:0% +Crystal yeah okay so very good but how + + + align:start position:0% +Crystal yeah okay so very good but how +come okay so it's only the veence + + align:start position:0% +come okay so it's only the veence + + + align:start position:0% +come okay so it's only the veence +because that's where all the chemistry + + align:start position:0% +because that's where all the chemistry + + + align:start position:0% +because that's where all the chemistry +happens we talked about that but um why + + align:start position:0% +happens we talked about that but um why + + + align:start position:0% +happens we talked about that but um why +are there only two atoms how can I + + align:start position:0% +are there only two atoms how can I + + + align:start position:0% +are there only two atoms how can I +simulate a solid with only two + + align:start position:0% + + + + align:start position:0% + +atoms because it's + + align:start position:0% +atoms because it's + + + align:start position:0% +atoms because it's +symmetric + + align:start position:0% +symmetric + + + align:start position:0% +symmetric +however because I only have two atoms + + align:start position:0% +however because I only have two atoms + + + align:start position:0% +however because I only have two atoms +especially and it's symmetric and it + + align:start position:0% +especially and it's symmetric and it + + + align:start position:0% +especially and it's symmetric and it +repeats I need to worry about the + + align:start position:0% +repeats I need to worry about the + + + align:start position:0% +repeats I need to worry about the +convergence of what which we just talked + + align:start position:0% +convergence of what which we just talked + + + align:start position:0% +convergence of what which we just talked +about + + align:start position:0% + + + + align:start position:0% + +and so you saw the density States we've + + align:start position:0% +and so you saw the density States we've + + + align:start position:0% +and so you saw the density States we've +talked about oh this beautiful look at + + align:start position:0% +talked about oh this beautiful look at + + + align:start position:0% +talked about oh this beautiful look at +this it's beautiful right those are the + + align:start position:0% +this it's beautiful right those are the + + + align:start position:0% +this it's beautiful right those are the +peaks of the solid of of Crystal and + + align:start position:0% +peaks of the solid of of Crystal and + + + align:start position:0% +peaks of the solid of of Crystal and +silicon it's just like in the molecules + + align:start position:0% +silicon it's just like in the molecules + + + align:start position:0% +silicon it's just like in the molecules +in the molecules we had the levels and + + align:start position:0% +in the molecules we had the levels and + + + align:start position:0% +in the molecules we had the levels and +we turn them on their + + align:start position:0% +we turn them on their + + + align:start position:0% +we turn them on their +side we turned the levels on their side + + align:start position:0% +side we turned the levels on their side + + + align:start position:0% +side we turned the levels on their side +and we said that's the same as the Doss + + align:start position:0% +and we said that's the same as the Doss + + + align:start position:0% +and we said that's the same as the Doss +but in the solid it's the band structure + + align:start position:0% +but in the solid it's the band structure + + + align:start position:0% +but in the solid it's the band structure +we turn on its side here's the band + + align:start position:0% +we turn on its side here's the band + + + align:start position:0% +we turn on its side here's the band +structure + + align:start position:0% +structure + + + align:start position:0% +structure +okay so those are my levels now those + + align:start position:0% +okay so those are my levels now those + + + align:start position:0% +okay so those are my levels now those +are my levels they're Wiggly in + + align:start position:0% +are my levels they're Wiggly in + + + align:start position:0% +are my levels they're Wiggly in +reciprocal space but if I turn I can + + align:start position:0% +reciprocal space but if I turn I can + + + align:start position:0% +reciprocal space but if I turn I can +still turn them on their side and when I + + align:start position:0% +still turn them on their side and when I + + + align:start position:0% +still turn them on their side and when I +do that I get the density of states + + align:start position:0% +do that I get the density of states + + + align:start position:0% +do that I get the density of states +right directly comparable to the + + align:start position:0% +right directly comparable to the + + + align:start position:0% +right directly comparable to the +situation of of the molecules but in the + + align:start position:0% +situation of of the molecules but in the + + + align:start position:0% +situation of of the molecules but in the +molecules what I turned on the side + + align:start position:0% +molecules what I turned on the side + + + align:start position:0% +molecules what I turned on the side +didn't wiggle okay does everybody see + + align:start position:0% +didn't wiggle okay does everybody see + + + align:start position:0% +didn't wiggle okay does everybody see +that okay so there's the band structure + + align:start position:0% +that okay so there's the band structure + + + align:start position:0% +that okay so there's the band structure +now this is um the Nano Hub has issues + + align:start position:0% +now this is um the Nano Hub has issues + + + align:start position:0% +now this is um the Nano Hub has issues +with putting um Greek letters on plots + + align:start position:0% +with putting um Greek letters on plots + + + align:start position:0% +with putting um Greek letters on plots +so this is the band structure with the + + align:start position:0% +so this is the band structure with the + + + align:start position:0% +so this is the band structure with the +Greek letters and I'll talk about well + + align:start position:0% +Greek letters and I'll talk about well + + + align:start position:0% +Greek letters and I'll talk about well +actually I don't need to wait these just + + align:start position:0% +actually I don't need to wait these just + + + align:start position:0% +actually I don't need to wait these just +correspond to different points in that + + align:start position:0% +correspond to different points in that + + + align:start position:0% +correspond to different points in that +bran zone right you you cruise through + + align:start position:0% +bran zone right you you cruise through + + + align:start position:0% +bran zone right you you cruise through +phase space in the bran Zone and you + + align:start position:0% +phase space in the bran Zone and you + + + align:start position:0% +phase space in the bran Zone and you +plot the energies the code is plotting + + align:start position:0% +plot the energies the code is plotting + + + align:start position:0% +plot the energies the code is plotting +the energies along that that path so you + + align:start position:0% +the energies along that that path so you + + + align:start position:0% +the energies along that that path so you +get a sense of the + + align:start position:0% +get a sense of the + + + align:start position:0% +get a sense of the +variation could these + + align:start position:0% +variation could these + + + align:start position:0% +variation could these +energies vary differently than I've + + align:start position:0% +energies vary differently than I've + + + align:start position:0% +energies vary differently than I've +plotted + + align:start position:0% +plotted + + + align:start position:0% +plotted +here could they vary + + align:start position:0% + + + + align:start position:0% + +differently how could they vary + + align:start position:0% +differently how could they vary + + + align:start position:0% +differently how could they vary +differently the answer is + + align:start position:0% + + + + align:start position:0% + +yes this is a cruise through face Bas + + align:start position:0% +yes this is a cruise through face Bas + + + align:start position:0% +yes this is a cruise through face Bas +gamma is always the origin gamma is at + + align:start position:0% +gamma is always the origin gamma is at + + + align:start position:0% +gamma is always the origin gamma is at +k. and then I went to some other K point + + align:start position:0% +k. and then I went to some other K point + + + align:start position:0% +k. and then I went to some other K point +and we called it X we like to give High + + align:start position:0% +and we called it X we like to give High + + + align:start position:0% +and we called it X we like to give High +symmetry um points in the bran Zone a + + align:start position:0% +symmetry um points in the bran Zone a + + + align:start position:0% +symmetry um points in the bran Zone a +letter right a Greek letter um or not um + + align:start position:0% +letter right a Greek letter um or not um + + + align:start position:0% +letter right a Greek letter um or not um +and then I went back to gamma here I + + align:start position:0% +and then I went back to gamma here I + + + align:start position:0% +and then I went back to gamma here I +went to a point we called + + align:start position:0% +went to a point we called + + + align:start position:0% +went to a point we called +L and I the way you do this is you just + + align:start position:0% +L and I the way you do this is you just + + + align:start position:0% +L and I the way you do this is you just +basically go in a line from this point + + align:start position:0% +basically go in a line from this point + + + align:start position:0% +basically go in a line from this point +to that point and you plot the change in + + align:start position:0% +to that point and you plot the change in + + + align:start position:0% +to that point and you plot the change in +the energy of each band as you go from + + align:start position:0% +the energy of each band as you go from + + + align:start position:0% +the energy of each band as you go from +point to point in the BR one zone so now + + align:start position:0% +point to point in the BR one zone so now + + + align:start position:0% +point to point in the BR one zone so now +tell me are those the only variations + + align:start position:0% +tell me are those the only variations + + + align:start position:0% +tell me are those the only variations +that you could have why not + + align:start position:0% + + + + align:start position:0% + +tell me why + + align:start position:0% + + + + align:start position:0% + +not if you choose a different path this + + align:start position:0% +not if you choose a different path this + + + align:start position:0% +not if you choose a different path this +is just one path going from L to gamma + + align:start position:0% +is just one path going from L to gamma + + + align:start position:0% +is just one path going from L to gamma +to X you see here we are I went you see + + align:start position:0% +to X you see here we are I went you see + + + align:start position:0% +to X you see here we are I went you see +here they are for FCC okay I think or + + align:start position:0% +here they are for FCC okay I think or + + + align:start position:0% +here they are for FCC okay I think or +maybe it's BCC I went from gamma to L to + + align:start position:0% +maybe it's BCC I went from gamma to L to + + + align:start position:0% +maybe it's BCC I went from gamma to L to +X I went just along a line in this bran + + align:start position:0% +X I went just along a line in this bran + + + align:start position:0% +X I went just along a line in this bran +Zone but what if I had gone G like this + + align:start position:0% +Zone but what if I had gone G like this + + + align:start position:0% +Zone but what if I had gone G like this +or what if I had done like + + align:start position:0% +or what if I had done like + + + align:start position:0% +or what if I had done like +this would I get different + + align:start position:0% +this would I get different + + + align:start position:0% +this would I get different +curvatures you better believe + + align:start position:0% +curvatures you better believe + + + align:start position:0% +curvatures you better believe +it right you are taking paths through + + align:start position:0% +it right you are taking paths through + + + align:start position:0% +it right you are taking paths through +the bruan zone to get the band structure + + align:start position:0% +the bruan zone to get the band structure + + + align:start position:0% +the bruan zone to get the band structure +that's how you got the band + + align:start position:0% + + + + align:start position:0% + +structure + + align:start position:0% + + + + align:start position:0% + +now what ends up + + align:start position:0% +now what ends up + + + align:start position:0% +now what ends up +happening is that the interesting + + align:start position:0% +happening is that the interesting + + + align:start position:0% +happening is that the interesting +variations in these energy bands the + + align:start position:0% +variations in these energy bands the + + + align:start position:0% +variations in these energy bands the +interesting ones the ones that are + + align:start position:0% +interesting ones the ones that are + + + align:start position:0% +interesting ones the ones that are +important for optical and electronic + + align:start position:0% +important for optical and electronic + + + align:start position:0% +important for optical and electronic +properties tend to happen between the + + align:start position:0% +properties tend to happen between the + + + align:start position:0% +properties tend to happen between the +high symmetry points in the Broan Zone + + align:start position:0% +high symmetry points in the Broan Zone + + + align:start position:0% +high symmetry points in the Broan Zone +they tend to happen between the origin + + align:start position:0% +they tend to happen between the origin + + + align:start position:0% +they tend to happen between the origin +and the center of this face and the + + align:start position:0% +and the center of this face and the + + + align:start position:0% +and the center of this face and the +center of this Edge and going back to An + + align:start position:0% +center of this Edge and going back to An + + + align:start position:0% +center of this Edge and going back to An +Origin they tend to happen between the + + align:start position:0% +Origin they tend to happen between the + + + align:start position:0% +Origin they tend to happen between the +the path of one high symmetry point to + + align:start position:0% +the path of one high symmetry point to + + + align:start position:0% +the path of one high symmetry point to +another and so you know sort of de facto + + align:start position:0% +another and so you know sort of de facto + + + align:start position:0% +another and so you know sort of de facto +we we we just don't care much about + + align:start position:0% +we we we just don't care much about + + + align:start position:0% +we we we just don't care much about +everything else in the B one Z because + + align:start position:0% +everything else in the B one Z because + + + align:start position:0% +everything else in the B one Z because +it doesn't really give us extra + + align:start position:0% +it doesn't really give us extra + + + align:start position:0% +it doesn't really give us extra +information it would give us a different + + align:start position:0% +information it would give us a different + + + align:start position:0% +information it would give us a different +band structure but it's not that um it's + + align:start position:0% +band structure but it's not that um it's + + + align:start position:0% +band structure but it's not that um it's +not giving us something that's um uh + + align:start position:0% +not giving us something that's um uh + + + align:start position:0% +not giving us something that's um uh +that's as relevant to the key + + align:start position:0% +that's as relevant to the key + + + align:start position:0% +that's as relevant to the key +fundamental properties we care about + + align:start position:0% +fundamental properties we care about + + + align:start position:0% +fundamental properties we care about +okay um so that's one thing now so + + align:start position:0% +okay um so that's one thing now so + + + align:start position:0% +okay um so that's one thing now so +that's where those now um the code just + + align:start position:0% +that's where those now um the code just + + + align:start position:0% +that's where those now um the code just +picks the paths but in all these codes + + align:start position:0% +picks the paths but in all these codes + + + align:start position:0% +picks the paths but in all these codes +you can enter whatever path you want so + + align:start position:0% +you can enter whatever path you want so + + + align:start position:0% +you can enter whatever path you want so +if you want to cruise around in caspace + + align:start position:0% +if you want to cruise around in caspace + + + align:start position:0% +if you want to cruise around in caspace +and get energy variations you can do it + + align:start position:0% +and get energy variations you can do it + + + align:start position:0% +and get energy variations you can do it +you are not + + align:start position:0% +you are not + + + align:start position:0% +you are not +limited um now uh is this the right band + + align:start position:0% +limited um now uh is this the right band + + + align:start position:0% +limited um now uh is this the right band +structure for + + align:start position:0% + + + + align:start position:0% + +silicon let's go back to our not bad + + align:start position:0% +silicon let's go back to our not bad + + + align:start position:0% +silicon let's go back to our not bad +look pretty good I like that that's what + + align:start position:0% +look pretty good I like that that's what + + + align:start position:0% +look pretty good I like that that's what +I want now if we go back to the + + align:start position:0% +I want now if we go back to the + + + align:start position:0% +I want now if we go back to the +input what is it that that um of these + + align:start position:0% +input what is it that that um of these + + + align:start position:0% +input what is it that that um of these +parameters what is it that I might need + + align:start position:0% +parameters what is it that I might need + + + align:start position:0% +parameters what is it that I might need +to + + align:start position:0% +to + + + align:start position:0% +to +check what is that say that + + align:start position:0% +check what is that say that + + + align:start position:0% +check what is that say that +again okay so I might I have a 4x4 grid + + align:start position:0% +again okay so I might I have a 4x4 grid + + + align:start position:0% +again okay so I might I have a 4x4 grid +would I get a B would I get curvy band + + align:start position:0% +would I get a B would I get curvy band + + + align:start position:0% +would I get a B would I get curvy band +structures if I do a one by one by + + align:start position:0% +structures if I do a one by one by + + + align:start position:0% +structures if I do a one by one by +one ah let's see let's try + + align:start position:0% +one ah let's see let's try + + + align:start position:0% +one ah let's see let's try +it don't do + + align:start position:0% + + + + align:start position:0% + +14 okay um this seems to be stable for + + align:start position:0% +14 okay um this seems to be stable for + + + align:start position:0% +14 okay um this seems to be stable for +now uh + + align:start position:0% +now uh + + + align:start position:0% +now uh +oh where's my simulate + + align:start position:0% +oh where's my simulate + + + align:start position:0% +oh where's my simulate +button + + align:start position:0% + + + + align:start position:0% + +ah + + align:start position:0% + + + + align:start position:0% + +okay uh there it is okay so I'm doing a + + align:start position:0% +okay uh there it is okay so I'm doing a + + + align:start position:0% +okay uh there it is okay so I'm doing a +one by + + align:start position:0% +one by + + + align:start position:0% +one by +one + + align:start position:0% +one + + + align:start position:0% +one +um one by one by one k point this is + + align:start position:0% +um one by one by one k point this is + + + align:start position:0% +um one by one by one k point this is +kind of another key concept I want to + + align:start position:0% +kind of another key concept I want to + + + align:start position:0% +kind of another key concept I want to +make make sure we understand okay there + + align:start position:0% +make make sure we understand okay there + + + align:start position:0% +make make sure we understand okay there +it is there's silicon I didn't change + + align:start position:0% +it is there's silicon I didn't change + + + align:start position:0% +it is there's silicon I didn't change +anything about the real space I didn't + + align:start position:0% +anything about the real space I didn't + + + align:start position:0% +anything about the real space I didn't +change anything about the k space I just + + align:start position:0% +change anything about the k space I just + + + align:start position:0% +change anything about the k space I just +only evaluated the density at one point + + align:start position:0% +only evaluated the density at one point + + + align:start position:0% +only evaluated the density at one point +now here's what's going to perhaps + + align:start position:0% +now here's what's going to perhaps + + + align:start position:0% +now here's what's going to perhaps +surprise you which is that the band + + align:start position:0% +surprise you which is that the band + + + align:start position:0% +surprise you which is that the band +structure still + + align:start position:0% + + + + align:start position:0% + +curves now um and it curves differently + + align:start position:0% +curves now um and it curves differently + + + align:start position:0% +curves now um and it curves differently +actually um than it did when I had 4x4x4 + + align:start position:0% +actually um than it did when I had 4x4x4 + + + align:start position:0% +actually um than it did when I had 4x4x4 +um why would it still + + align:start position:0% + + + + align:start position:0% + +curve this is actually uh something I + + align:start position:0% +curve this is actually uh something I + + + align:start position:0% +curve this is actually uh something I +didn't talk about yet but it is in a + + align:start position:0% +didn't talk about yet but it is in a + + + align:start position:0% +didn't talk about yet but it is in a +slide that I was going to talk about but + + align:start position:0% +slide that I was going to talk about but + + + align:start position:0% +slide that I was going to talk about but +since I have it here I'll just talk + + align:start position:0% +since I have it here I'll just talk + + + align:start position:0% +since I have it here I'll just talk +about it now + + align:start position:0% +about it now + + + align:start position:0% +about it now +yeah I probably could have done all that + + align:start position:0% +yeah I probably could have done all that + + + align:start position:0% +yeah I probably could have done all that +internally without voicing it but here + + align:start position:0% +internally without voicing it but here + + + align:start position:0% +internally without voicing it but here +we are um so uh you see when you + + align:start position:0% +we are um so uh you see when you + + + align:start position:0% +we are um so uh you see when you +calculate the band structure + + align:start position:0% +calculate the band structure + + + align:start position:0% +calculate the band structure +what you do is you do two things first + + align:start position:0% +what you do is you do two things first + + + align:start position:0% +what you do is you do two things first +you converge the wave function in + + align:start position:0% +you converge the wave function in + + + align:start position:0% +you converge the wave function in +density first you converge the density + + align:start position:0% +density first you converge the density + + + align:start position:0% +density first you converge the density +at the K points I input into the + + align:start position:0% +at the K points I input into the + + + align:start position:0% +at the K points I input into the +input right so I have a 1 by one by one + + align:start position:0% +input right so I have a 1 by one by one + + + align:start position:0% +input right so I have a 1 by one by one +kpoint density well that gives me some + + align:start position:0% +kpoint density well that gives me some + + + align:start position:0% +kpoint density well that gives me some +uh uh grid that gives me some density + + align:start position:0% +uh uh grid that gives me some density + + + align:start position:0% +uh uh grid that gives me some density +and some wave function + + align:start position:0% +and some wave function + + + align:start position:0% +and some wave function +okay now then to calculate the band + + align:start position:0% +okay now then to calculate the band + + + align:start position:0% +okay now then to calculate the band +structure what the code does is it does + + align:start position:0% +structure what the code does is it does + + + align:start position:0% +structure what the code does is it does +a second step it takes that converge + + align:start position:0% +a second step it takes that converge + + + align:start position:0% +a second step it takes that converge +density and it cruises around in kpace + + align:start position:0% +density and it cruises around in kpace + + + align:start position:0% +density and it cruises around in kpace +and that's how it plots this out but it + + align:start position:0% +and that's how it plots this out but it + + + align:start position:0% +and that's how it plots this out but it +doesn't change the density anymore it + + align:start position:0% +doesn't change the density anymore it + + + align:start position:0% +doesn't change the density anymore it +doesn't change the converg wave function + + align:start position:0% +doesn't change the converg wave function + + + align:start position:0% +doesn't change the converg wave function +it just evaluates it at all kinds of + + align:start position:0% +it just evaluates it at all kinds of + + + align:start position:0% +it just evaluates it at all kinds of +different points in kpace so there's two + + align:start position:0% +different points in kpace so there's two + + + align:start position:0% +different points in kpace so there's two +steps first you converge the density at + + align:start position:0% +steps first you converge the density at + + + align:start position:0% +steps first you converge the density at +some number of K + + align:start position:0% +some number of K + + + align:start position:0% +some number of K +points then you cruise around in the + + align:start position:0% +points then you cruise around in the + + + align:start position:0% +points then you cruise around in the +bribon zone with that density and you + + align:start position:0% +bribon zone with that density and you + + + align:start position:0% +bribon zone with that density and you +evaluate your functions and sure the D + + align:start position:0% +evaluate your functions and sure the D + + + align:start position:0% +evaluate your functions and sure the D +you know the wrong density will still + + align:start position:0% +you know the wrong density will still + + + align:start position:0% +you know the wrong density will still +wiggle as you move around in kpace it'll + + align:start position:0% +wiggle as you move around in kpace it'll + + + align:start position:0% +wiggle as you move around in kpace it'll +still wiggle but it's the wrong density + + align:start position:0% +still wiggle but it's the wrong density + + + align:start position:0% +still wiggle but it's the wrong density +because I didn't have enough K points in + + align:start position:0% +because I didn't have enough K points in + + + align:start position:0% +because I didn't have enough K points in +the first place to converge it does + + align:start position:0% +the first place to converge it does + + + align:start position:0% +the first place to converge it does +everybody see + + align:start position:0% +everybody see + + + align:start position:0% +everybody see +that okay so now how many k points do I + + align:start position:0% +that okay so now how many k points do I + + + align:start position:0% +that okay so now how many k points do I +need well the number of K points I need + + align:start position:0% +need well the number of K points I need + + + align:start position:0% +need well the number of K points I need +is when this converges and doesn't + + align:start position:0% +is when this converges and doesn't + + + align:start position:0% +is when this converges and doesn't +change anymore right if the band + + align:start position:0% +change anymore right if the band + + + align:start position:0% +change anymore right if the band +structure if properties of the band + + align:start position:0% +structure if properties of the band + + + align:start position:0% +structure if properties of the band +structure are what I want that's how + + align:start position:0% +structure are what I want that's how + + + align:start position:0% +structure are what I want that's how +many k points I need right + + align:start position:0% +many k points I need right + + + align:start position:0% +many k points I need right +does everybody see that that's the + + align:start position:0% +does everybody see that that's the + + + align:start position:0% +does everybody see that that's the +difference now + + align:start position:0% +difference now + + + align:start position:0% +difference now +uh okay ah no that wasn't good here we + + align:start position:0% +uh okay ah no that wasn't good here we + + + align:start position:0% +uh okay ah no that wasn't good here we +go oh yeah these so-called web browsers + + align:start position:0% +go oh yeah these so-called web browsers + + + align:start position:0% +go oh yeah these so-called web browsers +Mark andreon was my student by the way + + align:start position:0% +Mark andreon was my student by the way + + + align:start position:0% +Mark andreon was my student by the way +at uh does anybody know who he is nobody + + align:start position:0% +at uh does anybody know who he is nobody + + + align:start position:0% +at uh does anybody know who he is nobody +knows who he is I'm dated no um he was + + align:start position:0% +knows who he is I'm dated no um he was + + + align:start position:0% +knows who he is I'm dated no um he was +at Illinois where I did my PhD and I was + + align:start position:0% +at Illinois where I did my PhD and I was + + + align:start position:0% +at Illinois where I did my PhD and I was +his ta and um he he went and founded + + align:start position:0% +his ta and um he he went and founded + + + align:start position:0% +his ta and um he he went and founded +Netscape right um good guy okay uh + + align:start position:0% +Netscape right um good guy okay uh + + + align:start position:0% +Netscape right um good guy okay uh +except that's not one of my browser + + align:start position:0% +except that's not one of my browser + + + align:start position:0% +except that's not one of my browser +options anymore so what what's up with + + align:start position:0% +options anymore so what what's up with + + + align:start position:0% +options anymore so what what's up with +that um now okay what I want to do now + + align:start position:0% +that um now okay what I want to do now + + + align:start position:0% +that um now okay what I want to do now +is the following I'm going to go to one + + align:start position:0% +is the following I'm going to go to one + + + align:start position:0% +is the following I'm going to go to one +atom + + align:start position:0% +atom + + + align:start position:0% +atom +okay and what I want to know is um and + + align:start position:0% +okay and what I want to know is um and + + + align:start position:0% +okay and what I want to know is um and +you can do that just like before you can + + align:start position:0% +you can do that just like before you can + + + align:start position:0% +you can do that just like before you can +kind of mess around + + align:start position:0% +kind of mess around + + + align:start position:0% +kind of mess around +okay one + + align:start position:0% +okay one + + + align:start position:0% +okay one +atom we'll just leave it at one k point + + align:start position:0% +atom we'll just leave it at one k point + + + align:start position:0% +atom we'll just leave it at one k point +and what I want to know is am I going to + + align:start position:0% +and what I want to know is am I going to + + + align:start position:0% +and what I want to know is am I going to +get a band structure with one atom in + + align:start position:0% +get a band structure with one atom in + + + align:start position:0% +get a band structure with one atom in +the unit + + align:start position:0% +the unit + + + align:start position:0% +the unit +cell oh there it is they're kind of far + + align:start position:0% +cell oh there it is they're kind of far + + + align:start position:0% +cell oh there it is they're kind of far +apart right what do you guys + + align:start position:0% + + + + align:start position:0% + +think that's one atom in the corner of + + align:start position:0% +think that's one atom in the corner of + + + align:start position:0% +think that's one atom in the corner of +an FCC + + align:start position:0% + + + + align:start position:0% + +cell will I get a band structure + + align:start position:0% +cell will I get a band structure + + + align:start position:0% +cell will I get a band structure +just say yes or + + align:start position:0% + + + + align:start position:0% + +no there it is now why is it + + align:start position:0% +no there it is now why is it + + + align:start position:0% +no there it is now why is it +curving let let me ask a different way + + align:start position:0% +curving let let me ask a different way + + + align:start position:0% +curving let let me ask a different way +how could I get these bands to stop + + align:start position:0% +how could I get these bands to stop + + + align:start position:0% +how could I get these bands to stop +curving just stop curving + + align:start position:0% +curving just stop curving + + + align:start position:0% +curving just stop curving +already what is that + + align:start position:0% +already what is that + + + align:start position:0% +already what is that +larger larger k space or other + + align:start position:0% +larger larger k space or other + + + align:start position:0% +larger larger k space or other +space why are they curving + + align:start position:0% +space why are they curving + + + align:start position:0% +space why are they curving +again why are these things curving + + align:start position:0% + + + + align:start position:0% + +yeah it has to do with + + align:start position:0% +yeah it has to do with + + + align:start position:0% +yeah it has to do with +that but why do you get we we talked you + + align:start position:0% +that but why do you get we we talked you + + + align:start position:0% +that but why do you get we we talked you +know a lot in the last half hour about + + align:start position:0% +know a lot in the last half hour about + + + align:start position:0% +know a lot in the last half hour about +how you get this variation in c space of + + align:start position:0% +how you get this variation in c space of + + + align:start position:0% +how you get this variation in c space of +the band why do you get that + + align:start position:0% + + + + align:start position:0% + +again why do you get that I mean you get + + align:start position:0% +again why do you get that I mean you get + + + align:start position:0% +again why do you get that I mean you get +it because of blocks theorem I'll tell + + align:start position:0% +it because of blocks theorem I'll tell + + + align:start position:0% +it because of blocks theorem I'll tell +you that but why does that matter + + align:start position:0% +you that but why does that matter + + + align:start position:0% +you that but why does that matter +it's + + align:start position:0% +it's + + + align:start position:0% +it's +periodic you got a periodic potential + + align:start position:0% +periodic you got a periodic potential + + + align:start position:0% +periodic you got a periodic potential +and so if it's so so when would you + + align:start position:0% +and so if it's so so when would you + + + align:start position:0% +and so if it's so so when would you +expect the curviness to stop + + align:start position:0% + + + + align:start position:0% + +curving well or if you don't really have + + align:start position:0% +curving well or if you don't really have + + + align:start position:0% +curving well or if you don't really have +a crystal anymore right I mean this + + align:start position:0% +a crystal anymore right I mean this + + + align:start position:0% +a crystal anymore right I mean this +looks a little less curvy what if I + + align:start position:0% +looks a little less curvy what if I + + + align:start position:0% +looks a little less curvy what if I +actually made the spacing if I change + + align:start position:0% +actually made the spacing if I change + + + align:start position:0% +actually made the spacing if I change +the lattice constant to + + align:start position:0% +the lattice constant to + + + align:start position:0% +the lattice constant to +10 and then simulated what's going to + + align:start position:0% +10 and then simulated what's going to + + + align:start position:0% +10 and then simulated what's going to +happen + + align:start position:0% + + + + align:start position:0% + +then okay that was pretty fast and look + + align:start position:0% +then okay that was pretty fast and look + + + align:start position:0% +then okay that was pretty fast and look +at that now they're far apart they sort + + align:start position:0% +at that now they're far apart they sort + + + align:start position:0% +at that now they're far apart they sort +of look + + align:start position:0% +of look + + + align:start position:0% +of look +like + + align:start position:0% +like + + + align:start position:0% +like +where let's see there's the band + + align:start position:0% +where let's see there's the band + + + align:start position:0% +where let's see there's the band +structure + + align:start position:0% +structure + + + align:start position:0% +structure +oh I love that reaction there that was + + align:start position:0% +oh I love that reaction there that was + + + align:start position:0% +oh I love that reaction there that was +that that had some meaning in it right + + align:start position:0% +that that had some meaning in it right + + + align:start position:0% +that that had some meaning in it right +whoever that was thank you cuz I felt + + align:start position:0% +whoever that was thank you cuz I felt + + + align:start position:0% +whoever that was thank you cuz I felt +the connection I what just just happened + + align:start position:0% +the connection I what just just happened + + + align:start position:0% +the connection I what just just happened +what is this what are + + align:start position:0% + + + + align:start position:0% + +these energy bands they are still energy + + align:start position:0% +these energy bands they are still energy + + + align:start position:0% +these energy bands they are still energy +bands varying in k space but they don't + + align:start position:0% +bands varying in k space but they don't + + + align:start position:0% +bands varying in k space but they don't +vary in k space but you doesn't mean you + + align:start position:0% +vary in k space but you doesn't mean you + + + align:start position:0% +vary in k space but you doesn't mean you +can't compute them at different K points + + align:start position:0% +can't compute them at different K points + + + align:start position:0% +can't compute them at different K points +which the code did but they're flat + + align:start position:0% +which the code did but they're flat + + + align:start position:0% +which the code did but they're flat +which means they're not + + align:start position:0% +which means they're not + + + align:start position:0% +which means they're not +really interacting in any sort of + + align:start position:0% +really interacting in any sort of + + + align:start position:0% +really interacting in any sort of +periodic way anymore they're so far + + align:start position:0% +periodic way anymore they're so far + + + align:start position:0% +periodic way anymore they're so far +apart that the periodic potentials don't + + align:start position:0% +apart that the periodic potentials don't + + + align:start position:0% +apart that the periodic potentials don't +really overlap they don't feel each + + align:start position:0% +really overlap they don't feel each + + + align:start position:0% +really overlap they don't feel each +other so what do I have left then what + + align:start position:0% +other so what do I have left then what + + + align:start position:0% +other so what do I have left then what +is it what am I staring + + align:start position:0% +is it what am I staring + + + align:start position:0% +is it what am I staring +at silicon atom that's all that those + + align:start position:0% +at silicon atom that's all that those + + + align:start position:0% +at silicon atom that's all that those +are the states that's what state is + + align:start position:0% + + + + align:start position:0% + +that yeah but which which state is + + align:start position:0% + + + + align:start position:0% + +that it would be if we had all the + + align:start position:0% +that it would be if we had all the + + + align:start position:0% +that it would be if we had all the +electrons so that's a little tough but + + align:start position:0% +electrons so that's a little tough but + + + align:start position:0% +electrons so that's a little tough but +we only have the outer four so it's it's + + align:start position:0% +we only have the outer four so it's it's + + + align:start position:0% +we only have the outer four so it's it's +actually the 3s right 3s 3p our friend + + align:start position:0% +actually the 3s right 3s 3p our friend + + + align:start position:0% +actually the 3s right 3s 3p our friend +silicon atom is back we went from atoms + + align:start position:0% +silicon atom is back we went from atoms + + + align:start position:0% +silicon atom is back we went from atoms +to molecules to solids and now we just + + align:start position:0% +to molecules to solids and now we just + + + align:start position:0% +to molecules to solids and now we just +did an atom right um and you see as I + + align:start position:0% +did an atom right um and you see as I + + + align:start position:0% +did an atom right um and you see as I +bring those atoms as I so those are the + + align:start position:0% +bring those atoms as I so those are the + + + align:start position:0% +bring those atoms as I so those are the +atomic levels of + + align:start position:0% +atomic levels of + + + align:start position:0% +atomic levels of +silicon um they don't vary in case Spas + + align:start position:0% +silicon um they don't vary in case Spas + + + align:start position:0% +silicon um they don't vary in case Spas +a molecule of silicon wouldn't vary in + + align:start position:0% +a molecule of silicon wouldn't vary in + + + align:start position:0% +a molecule of silicon wouldn't vary in +case space but as I start to make this + + align:start position:0% +case space but as I start to make this + + + align:start position:0% +case space but as I start to make this +thing feel a + + align:start position:0% +thing feel a + + + align:start position:0% +thing feel a +repeat + + align:start position:0% +repeat + + + align:start position:0% +repeat +eness then block stum kicks in + + align:start position:0% +eness then block stum kicks in + + + align:start position:0% +eness then block stum kicks in +and energies depend on K and that + + align:start position:0% +and energies depend on K and that + + + align:start position:0% +and energies depend on K and that +changes the properties of the material + + align:start position:0% +changes the properties of the material + + + align:start position:0% +changes the properties of the material +okay so that's um that's all really + + align:start position:0% +okay so that's um that's all really + + + align:start position:0% +okay so that's um that's all really +important + + align:start position:0% +important + + + align:start position:0% +important +now one more thing while we have the + + align:start position:0% +now one more thing while we have the + + + align:start position:0% +now one more thing while we have the +tool + + align:start position:0% + + + + align:start position:0% + +up well so now we're actually we're + + align:start position:0% +up well so now we're actually we're + + + align:start position:0% +up well so now we're actually we're +pretty well equipped to try a whole + + align:start position:0% +pretty well equipped to try a whole + + + align:start position:0% +pretty well equipped to try a whole +bunch of stuff right and we're going to + + align:start position:0% +bunch of stuff right and we're going to + + + align:start position:0% +bunch of stuff right and we're going to +understand what we're doing let me just + + align:start position:0% +understand what we're doing let me just + + + align:start position:0% +understand what we're doing let me just +um ask you one more thing if I look at + + align:start position:0% +um ask you one more thing if I look at + + + align:start position:0% +um ask you one more thing if I look at +these inputs let's pull up uh Alpha + + align:start position:0% +these inputs let's pull up uh Alpha + + + align:start position:0% +these inputs let's pull up uh Alpha +quartz let's say there's Alpha + + align:start position:0% +quartz let's say there's Alpha + + + align:start position:0% +quartz let's say there's Alpha +quartz um now if I look at these inputs + + align:start position:0% +quartz um now if I look at these inputs + + + align:start position:0% +quartz um now if I look at these inputs +um what else might you want to think + + align:start position:0% +um what else might you want to think + + + align:start position:0% +um what else might you want to think +about converging we talked about the + + align:start position:0% +about converging we talked about the + + + align:start position:0% +about converging we talked about the +kpoint + + align:start position:0% +kpoint + + + align:start position:0% +kpoint +mesh uh something not as bad as Alpha + + align:start position:0% + + + + align:start position:0% + +quartz + + align:start position:0% +quartz + + + align:start position:0% +quartz +aluminum oh that's nice one + + align:start position:0% +aluminum oh that's nice one + + + align:start position:0% +aluminum oh that's nice one +atom what else besides the kpo mesh and + + align:start position:0% +atom what else besides the kpo mesh and + + + align:start position:0% +atom what else besides the kpo mesh and +you better use more K points than one + + align:start position:0% +you better use more K points than one + + + align:start position:0% +you better use more K points than one +for + + align:start position:0% +for + + + align:start position:0% +for +aluminum besides that what else might I + + align:start position:0% +aluminum besides that what else might I + + + align:start position:0% +aluminum besides that what else might I +just pointed to it might I want to + + align:start position:0% +just pointed to it might I want to + + + align:start position:0% +just pointed to it might I want to +converge or make sure is right the lce + + align:start position:0% +converge or make sure is right the lce + + + align:start position:0% +converge or make sure is right the lce +constant you see I'm just giv this to + + align:start position:0% +constant you see I'm just giv this to + + + align:start position:0% +constant you see I'm just giv this to +you because you know it's there um where + + align:start position:0% +you because you know it's there um where + + + align:start position:0% +you because you know it's there um where +did it come from is it the right lattice + + align:start position:0% +did it come from is it the right lattice + + + align:start position:0% +did it come from is it the right lattice +constant for this choice of theory and + + align:start position:0% +constant for this choice of theory and + + + align:start position:0% +constant for this choice of theory and +basis + + align:start position:0% +basis + + + align:start position:0% +basis +set right is it the right one well you + + align:start position:0% +set right is it the right one well you + + + align:start position:0% +set right is it the right one well you +should you should make sure there are no + + align:start position:0% +should you should make sure there are no + + + align:start position:0% +should you should make sure there are no +forces in the system you should relax + + align:start position:0% +forces in the system you should relax + + + align:start position:0% +forces in the system you should relax +your system and that gets to the point I + + align:start position:0% +your system and that gets to the point I + + + align:start position:0% +your system and that gets to the point I +want to make how do you relax a solid + + align:start position:0% +want to make how do you relax a solid + + + align:start position:0% +want to make how do you relax a solid +because there's now two things not one + + align:start position:0% +because there's now two things not one + + + align:start position:0% +because there's now two things not one +that you need to care about tell me what + + align:start position:0% +that you need to care about tell me what + + + align:start position:0% +that you need to care about tell me what +the two things + + align:start position:0% + + + + align:start position:0% + +are well how do you relax a molecule + + align:start position:0% +are well how do you relax a molecule + + + align:start position:0% +are well how do you relax a molecule +when you say optimize structure what's + + align:start position:0% +when you say optimize structure what's + + + align:start position:0% +when you say optimize structure what's +it + + align:start position:0% + + + + align:start position:0% + +doing okay by doing + + align:start position:0% +doing okay by doing + + + align:start position:0% +doing okay by doing +what what's it + + align:start position:0% + + + + align:start position:0% + +calculate which is also called what + + align:start position:0% +calculate which is also called what + + + align:start position:0% +calculate which is also called what +force the force on each at and it pushes + + align:start position:0% +force the force on each at and it pushes + + + align:start position:0% +force the force on each at and it pushes +them along the force until they get to + + align:start position:0% +them along the force until they get to + + + align:start position:0% +them along the force until they get to +some minimum right now when I have a + + align:start position:0% +some minimum right now when I have a + + + align:start position:0% +some minimum right now when I have a +solid I have two things I have the force + + align:start position:0% +solid I have two things I have the force + + + align:start position:0% +solid I have two things I have the force +on each atom same as in the molecule the + + align:start position:0% +on each atom same as in the molecule the + + + align:start position:0% +on each atom same as in the molecule the +force on each atom in the basis as well + + align:start position:0% +force on each atom in the basis as well + + + align:start position:0% +force on each atom in the basis as well +as + + align:start position:0% + + + + align:start position:0% + +what the volume which is set by the what + + align:start position:0% +what the volume which is set by the what + + + align:start position:0% +what the volume which is set by the what +by the lattice constant okay so you need + + align:start position:0% +by the lattice constant okay so you need + + + align:start position:0% +by the lattice constant okay so you need +to converge both of + + align:start position:0% +to converge both of + + + align:start position:0% +to converge both of +those okay and well in aluminum there's + + align:start position:0% +those okay and well in aluminum there's + + + align:start position:0% +those okay and well in aluminum there's +only one atom in the basis because you + + align:start position:0% +only one atom in the basis because you + + + align:start position:0% +only one atom in the basis because you +see aluminum is is an FCC + + align:start position:0% +see aluminum is is an FCC + + + align:start position:0% +see aluminum is is an FCC +metal so all I need is one atom in the + + align:start position:0% +metal so all I need is one atom in the + + + align:start position:0% +metal so all I need is one atom in the +corner of an FCC unit cell and I can + + align:start position:0% +corner of an FCC unit cell and I can + + + align:start position:0% +corner of an FCC unit cell and I can +simulate it but there is the lattice + + align:start position:0% +simulate it but there is the lattice + + + align:start position:0% +simulate it but there is the lattice +constant that I need to play with now if + + align:start position:0% +constant that I need to play with now if + + + align:start position:0% +constant that I need to play with now if +I had a more complex solid like Alpha + + align:start position:0% +I had a more complex solid like Alpha + + + align:start position:0% +I had a more complex solid like Alpha +quartz which has a number of atoms in + + align:start position:0% +quartz which has a number of atoms in + + + align:start position:0% +quartz which has a number of atoms in +the basis then the relative positions of + + align:start position:0% +the basis then the relative positions of + + + align:start position:0% +the basis then the relative positions of +those atoms may be + + align:start position:0% +those atoms may be + + + align:start position:0% +those atoms may be +important + + align:start position:0% +important + + + align:start position:0% +important +right um and you may need to relax that + + align:start position:0% +right um and you may need to relax that + + + align:start position:0% +right um and you may need to relax that +you may may not but it's something you + + align:start position:0% +you may may not but it's something you + + + align:start position:0% +you may may not but it's something you +need to be aware of and you can go in + + align:start position:0% +need to be aware of and you can go in + + + align:start position:0% +need to be aware of and you can go in +and you can look at the forces on these + + align:start position:0% +and you can look at the forces on these + + + align:start position:0% +and you can look at the forces on these +materials and you definitely have to + + align:start position:0% +materials and you definitely have to + + + align:start position:0% +materials and you definitely have to +know um whether you're at the minimum in + + align:start position:0% +know um whether you're at the minimum in + + + align:start position:0% +know um whether you're at the minimum in +terms of the lattice constant okay so + + align:start position:0% +terms of the lattice constant okay so + + + align:start position:0% +terms of the lattice constant okay so +let's do aluminum just because it's here + + align:start position:0% +let's do aluminum just because it's here + + + align:start position:0% +let's do aluminum just because it's here +we'll do 4K points which is not enough + + align:start position:0% +we'll do 4K points which is not enough + + + align:start position:0% +we'll do 4K points which is not enough +to look at a metal but we'll do it + + align:start position:0% +to look at a metal but we'll do it + + + align:start position:0% +to look at a metal but we'll do it +because it should be fairly + + align:start position:0% +because it should be fairly + + + align:start position:0% +because it should be fairly +fast + + align:start position:0% +fast + + + align:start position:0% +fast +um okay there's the energy + + align:start position:0% + + + + align:start position:0% + +and oh look at that isn't that beautiful + + align:start position:0% +and oh look at that isn't that beautiful + + + align:start position:0% +and oh look at that isn't that beautiful +it new to change the color and + + align:start position:0% +it new to change the color and + + + align:start position:0% +it new to change the color and +everything very smart smart tool and + + align:start position:0% +everything very smart smart tool and + + + align:start position:0% +everything very smart smart tool and +here we go back and tell me somebody + + align:start position:0% +here we go back and tell me somebody + + + align:start position:0% +here we go back and tell me somebody +tell me what they think the band + + align:start position:0% +tell me what they think the band + + + align:start position:0% +tell me what they think the band +structure is going to look like for + + align:start position:0% + + + + align:start position:0% + +aluminum is it going to be what + + align:start position:0% +aluminum is it going to be what + + + align:start position:0% +aluminum is it going to be what +flatv curved how many you say curved how + + align:start position:0% +flatv curved how many you say curved how + + + align:start position:0% +flatv curved how many you say curved how +many say + + align:start position:0% +many say + + + align:start position:0% +many say +flat okay + + align:start position:0% +flat okay + + + align:start position:0% +flat okay +good look at that that's curved that's + + align:start position:0% +good look at that that's curved that's + + + align:start position:0% +good look at that that's curved that's +seriously curved right um and if we + + align:start position:0% +seriously curved right um and if we + + + align:start position:0% +seriously curved right um and if we +include you know if we looked at + + align:start position:0% +include you know if we looked at + + + align:start position:0% +include you know if we looked at +different energies we'd see even more + + align:start position:0% +different energies we'd see even more + + + align:start position:0% +different energies we'd see even more +spaghetti right um lots of curvy oh and + + align:start position:0% +spaghetti right um lots of curvy oh and + + + align:start position:0% +spaghetti right um lots of curvy oh and +look at this oh let's get the Doss this + + align:start position:0% +look at this oh let's get the Doss this + + + align:start position:0% +look at this oh let's get the Doss this +is so exciting I forgot about the + + align:start position:0% +is so exciting I forgot about the + + + align:start position:0% +is so exciting I forgot about the +Doss there's the Doss near the firmy + + align:start position:0% +Doss there's the Doss near the firmy + + + align:start position:0% +Doss there's the Doss near the firmy +energy + + align:start position:0% +energy + + + align:start position:0% +energy +okay firy energy is right here is there + + align:start position:0% +okay firy energy is right here is there + + + align:start position:0% +okay firy energy is right here is there +a Gap in this material no Should there + + align:start position:0% +a Gap in this material no Should there + + + align:start position:0% +a Gap in this material no Should there +have been no because remember in a metal + + align:start position:0% +have been no because remember in a metal + + + align:start position:0% +have been no because remember in a metal +you've got States coming coming in all + + align:start position:0% +you've got States coming coming in all + + + align:start position:0% +you've got States coming coming in all +over the place from below the firy + + align:start position:0% +over the place from below the firy + + + align:start position:0% +over the place from below the firy +energy and above continues across it + + align:start position:0% +energy and above continues across it + + + align:start position:0% +energy and above continues across it +right that's what tells you it's a + + align:start position:0% +right that's what tells you it's a + + + align:start position:0% +right that's what tells you it's a +metal okay now is Alpha quartz let's + + align:start position:0% +metal okay now is Alpha quartz let's + + + align:start position:0% +metal okay now is Alpha quartz let's +that's a nice material mostly um I want + + align:start position:0% +that's a nice material mostly um I want + + + align:start position:0% +that's a nice material mostly um I want +to simulate it CU I think it'll be + + align:start position:0% +to simulate it CU I think it'll be + + + align:start position:0% +to simulate it CU I think it'll be +pretty + + align:start position:0% +pretty + + + align:start position:0% +pretty +looking and there it is now is Alpha + + align:start position:0% +looking and there it is now is Alpha + + + align:start position:0% +looking and there it is now is Alpha +quartz I'm going to go down + + align:start position:0% +quartz I'm going to go down + + + align:start position:0% +quartz I'm going to go down +to + + align:start position:0% +to + + + align:start position:0% +to +two by + + align:start position:0% + + + + align:start position:0% + +two is Alpha quartz a metal or a + + align:start position:0% +two is Alpha quartz a metal or a + + + align:start position:0% +two is Alpha quartz a metal or a +semiconductor or what is + + align:start position:0% + + + + align:start position:0% + +it + + align:start position:0% +it + + + align:start position:0% +it +insulator yeah what's one clue to the + + align:start position:0% +insulator yeah what's one clue to the + + + align:start position:0% +insulator yeah what's one clue to the +fact that it's an insulator + + align:start position:0% +fact that it's an insulator + + + align:start position:0% +fact that it's an insulator +what is that + + align:start position:0% + + + + align:start position:0% + +in I'm that easy to read man I got to + + align:start position:0% +in I'm that easy to read man I got to + + + align:start position:0% +in I'm that easy to read man I got to +work on that is it an insulator or a + + align:start position:0% +work on that is it an insulator or a + + + align:start position:0% +work on that is it an insulator or a +metal um I I'll try well besides the + + align:start position:0% +metal um I I'll try well besides the + + + align:start position:0% +metal um I I'll try well besides the +inflection in my voice what else could + + align:start position:0% +inflection in my voice what else could + + + align:start position:0% +inflection in my voice what else could +give you a + + align:start position:0% + + + + align:start position:0% + +clue well look at it right like is it is + + align:start position:0% +clue well look at it right like is it is + + + align:start position:0% +clue well look at it right like is it is +it a transparent material well you can't + + align:start position:0% +it a transparent material well you can't + + + align:start position:0% +it a transparent material well you can't +tell there oh it is pretty look at this + + align:start position:0% +tell there oh it is pretty look at this + + + align:start position:0% +tell there oh it is pretty look at this +Isn't that cool see this is a this is a + + align:start position:0% +Isn't that cool see this is a this is a + + + align:start position:0% +Isn't that cool see this is a this is a +a periodically repeating structure but + + align:start position:0% +a periodically repeating structure but + + + align:start position:0% +a periodically repeating structure but +the basis has nine atoms in it right + + align:start position:0% +the basis has nine atoms in it right + + + align:start position:0% +the basis has nine atoms in it right +it's a more complex + + align:start position:0% +it's a more complex + + + align:start position:0% +it's a more complex +structure okay and + + align:start position:0% +structure okay and + + + align:start position:0% +structure okay and +um and let's look now it's an insulator + + align:start position:0% +um and let's look now it's an insulator + + + align:start position:0% +um and let's look now it's an insulator +I'm going to I'm going to totally uh + + align:start position:0% +I'm going to I'm going to totally uh + + + align:start position:0% +I'm going to I'm going to totally uh +agree with that you see right through it + + align:start position:0% +agree with that you see right through it + + + align:start position:0% +agree with that you see right through it +right so you know it's not + + align:start position:0% +right so you know it's not + + + align:start position:0% +right so you know it's not +what absorbing in the visible at least + + align:start position:0% +what absorbing in the visible at least + + + align:start position:0% +what absorbing in the visible at least +right um but since it's an insulator + + align:start position:0% +right um but since it's an insulator + + + align:start position:0% +right um but since it's an insulator +um and it has a large band Gap even + + align:start position:0% +um and it has a large band Gap even + + + align:start position:0% +um and it has a large band Gap even +though it's a solid what do you think + + align:start position:0% +though it's a solid what do you think + + + align:start position:0% +though it's a solid what do you think +the bands are going to look like curvy + + align:start position:0% +the bands are going to look like curvy + + + align:start position:0% +the bands are going to look like curvy +or not so + + align:start position:0% + + + + align:start position:0% + +curvy that is curvy right they're not + + align:start position:0% +curvy that is curvy right they're not + + + align:start position:0% +curvy that is curvy right they're not +usually as curvy okay so here's the Doss + + align:start position:0% +usually as curvy okay so here's the Doss + + + align:start position:0% +usually as curvy okay so here's the Doss +look at that beautiful bang + + align:start position:0% +look at that beautiful bang + + + align:start position:0% +look at that beautiful bang +Gap this is a bang Gap + + align:start position:0% +Gap this is a bang Gap + + + align:start position:0% +Gap this is a bang Gap +only a mother could what father or + + align:start position:0% +only a mother could what father or + + + align:start position:0% +only a mother could what father or +mother I mean that's a beautiful and um + + align:start position:0% +mother I mean that's a beautiful and um + + + align:start position:0% +mother I mean that's a beautiful and um +look at this + + align:start position:0% +look at this + + + align:start position:0% +look at this +um there's the band structure okay and + + align:start position:0% +um there's the band structure okay and + + + align:start position:0% +um there's the band structure okay and +uh you can see that look at all those + + align:start position:0% +uh you can see that look at all those + + + align:start position:0% +uh you can see that look at all those +bands okay look at all those levels and + + align:start position:0% +bands okay look at all those levels and + + + align:start position:0% +bands okay look at all those levels and +they do curve they do curve but they're + + align:start position:0% +they do curve they do curve but they're + + + align:start position:0% +they do curve they do curve but they're +not as like crazy well they are kind of + + align:start position:0% +not as like crazy well they are kind of + + + align:start position:0% +not as like crazy well they are kind of +spaghetti like but they're not spaghetti + + align:start position:0% +spaghetti like but they're not spaghetti + + + align:start position:0% +spaghetti like but they're not spaghetti +like near the firmy energy or near the + + align:start position:0% +like near the firmy energy or near the + + + align:start position:0% +like near the firmy energy or near the +Gap so you look at that and you're like + + align:start position:0% +Gap so you look at that and you're like + + + align:start position:0% +Gap so you look at that and you're like +insulator first of all just because of + + align:start position:0% +insulator first of all just because of + + + align:start position:0% +insulator first of all just because of +how big the Gap is and then what we're + + align:start position:0% +how big the Gap is and then what we're + + + align:start position:0% +how big the Gap is and then what we're +going to do and I still have just 10 + + align:start position:0% +going to do and I still have just 10 + + + align:start position:0% +going to do and I still have just 10 +minutes more today but on on Thursday + + align:start position:0% +minutes more today but on on Thursday + + + align:start position:0% +minutes more today but on on Thursday +what we're going to do is we're going to + + align:start position:0% +what we're going to do is we're going to + + + align:start position:0% +what we're going to do is we're going to +show how when you look at this you can + + align:start position:0% +show how when you look at this you can + + + align:start position:0% +show how when you look at this you can +say not a very good conductor certainly + + align:start position:0% +say not a very good conductor certainly + + + align:start position:0% +say not a very good conductor certainly +not a good whole + + align:start position:0% +not a good whole + + + align:start position:0% +not a good whole +conductor this is where the holes would + + align:start position:0% +conductor this is where the holes would + + + align:start position:0% +conductor this is where the holes would +move this is where the electrons would + + align:start position:0% +move this is where the electrons would + + + align:start position:0% +move this is where the electrons would +move because we're going to get to that + + align:start position:0% +move because we're going to get to that + + + align:start position:0% +move because we're going to get to that +a little bit on Thursday band structure + + align:start position:0% +a little bit on Thursday band structure + + + align:start position:0% +a little bit on Thursday band structure +is so rich with information it's a + + align:start position:0% +is so rich with information it's a + + + align:start position:0% +is so rich with information it's a +beautiful thing it's + + align:start position:0% +beautiful thing it's + + + align:start position:0% +beautiful thing it's +emotional and if any of you are feeling + + align:start position:0% +emotional and if any of you are feeling + + + align:start position:0% +emotional and if any of you are feeling +that it's okay I'm touching the mic + + align:start position:0% +that it's okay I'm touching the mic + + + align:start position:0% +that it's okay I'm touching the mic +again sorry it's okay we're + + align:start position:0% +again sorry it's okay we're + + + align:start position:0% +again sorry it's okay we're +good check that Roger + + align:start position:0% +good check that Roger + + + align:start position:0% +good check that Roger +okay so + + align:start position:0% +okay so + + + align:start position:0% +okay so +okay we're we're simulating solids you + + align:start position:0% +okay we're we're simulating solids you + + + align:start position:0% +okay we're we're simulating solids you +understand about band structures we've + + align:start position:0% +understand about band structures we've + + + align:start position:0% +understand about band structures we've +talked about silicon + + align:start position:0% +talked about silicon + + + align:start position:0% +talked about silicon +um and occupied + + align:start position:0% +um and occupied + + + align:start position:0% +um and occupied +unoccupied okay you can get the + + align:start position:0% +unoccupied okay you can get the + + + align:start position:0% +unoccupied okay you can get the +densities just like you can in molecules + + align:start position:0% +densities just like you can in molecules + + + align:start position:0% +densities just like you can in molecules +um and as I said you can calculate um + + align:start position:0% +um and as I said you can calculate um + + + align:start position:0% +um and as I said you can calculate um +the + + align:start position:0% +the + + + align:start position:0% +the +uh uh well you need to find the + + align:start position:0% +uh uh well you need to find the + + + align:start position:0% +uh uh well you need to find the +equilibrium lattice constant okay and so + + align:start position:0% +equilibrium lattice constant okay and so + + + align:start position:0% +equilibrium lattice constant okay and so +if you if you if you just do the + + align:start position:0% +if you if you if you just do the + + + align:start position:0% +if you if you if you just do the +calculation at different lattice + + align:start position:0% +calculation at different lattice + + + align:start position:0% +calculation at different lattice +constants you'll get a variation in + + align:start position:0% +constants you'll get a variation in + + + align:start position:0% +constants you'll get a variation in +energy right that's what'll happen and + + align:start position:0% +energy right that's what'll happen and + + + align:start position:0% +energy right that's what'll happen and +you'll get a minimum and that'll be the + + align:start position:0% +you'll get a minimum and that'll be the + + + align:start position:0% +you'll get a minimum and that'll be the +lattice constant that you should run at + + align:start position:0% +lattice constant that you should run at + + + align:start position:0% +lattice constant that you should run at +for your simulations that's pretty + + align:start position:0% +for your simulations that's pretty + + + align:start position:0% +for your simulations that's pretty +important okay um but if you had that + + align:start position:0% +important okay um but if you had that + + + align:start position:0% +important okay um but if you had that +curve already well then you've also got + + align:start position:0% +curve already well then you've also got + + + align:start position:0% +curve already well then you've also got +the bulk modulus which is pretty cool + + align:start position:0% +the bulk modulus which is pretty cool + + + align:start position:0% +the bulk modulus which is pretty cool +now I think that you probably did this + + align:start position:0% +now I think that you probably did this + + + align:start position:0% +now I think that you probably did this +calculation using classical um + + align:start position:0% +calculation using classical um + + + align:start position:0% +calculation using classical um +potentials is that right + + align:start position:0% +potentials is that right + + + align:start position:0% +potentials is that right +you you calculated the bulk modulus so + + align:start position:0% +you you calculated the bulk modulus so + + + align:start position:0% +you you calculated the bulk modulus so +this isn't any different I mean it's + + align:start position:0% +this isn't any different I mean it's + + + align:start position:0% +this isn't any different I mean it's +just the did you do um you did + + align:start position:0% +just the did you do um you did + + + align:start position:0% +just the did you do um you did +periodically repeating structures + + align:start position:0% +periodically repeating structures + + + align:start position:0% +periodically repeating structures +right using classical force + + align:start position:0% + + + + align:start position:0% + +fields I'm seeing a whole lot of I'm not + + align:start position:0% +fields I'm seeing a whole lot of I'm not + + + align:start position:0% +fields I'm seeing a whole lot of I'm not +sure + + align:start position:0% +sure + + + align:start position:0% +sure +yeah it's a very I'm not sure kind of + + align:start position:0% +yeah it's a very I'm not sure kind of + + + align:start position:0% +yeah it's a very I'm not sure kind of +Bowman it's okay it's okay is it did did + + align:start position:0% +Bowman it's okay it's okay is it did did + + + align:start position:0% +Bowman it's okay it's okay is it did did +you look at solid materials in your + + align:start position:0% +you look at solid materials in your + + + align:start position:0% +you look at solid materials in your +homeworks it's still no not so sure + + align:start position:0% +homeworks it's still no not so sure + + + align:start position:0% +homeworks it's still no not so sure +silicon carbon not so + + align:start position:0% + + + + align:start position:0% + +much proteins okay so proteins are are + + align:start position:0% +much proteins okay so proteins are are + + + align:start position:0% +much proteins okay so proteins are are +um are a bit more complex of a beast by + + align:start position:0% +um are a bit more complex of a beast by + + + align:start position:0% +um are a bit more complex of a beast by +the way which you can't really do using + + align:start position:0% +the way which you can't really do using + + + align:start position:0% +the way which you can't really do using +I mean you can do parts of proteins + + align:start position:0% +I mean you can do parts of proteins + + + align:start position:0% +I mean you can do parts of proteins +using quantum mechanics but it's just + + align:start position:0% +using quantum mechanics but it's just + + + align:start position:0% +using quantum mechanics but it's just +too hard it's too big you know you can't + + align:start position:0% +too hard it's too big you know you can't + + + align:start position:0% +too hard it's too big you know you can't +do that many ATS right to do most uh + + align:start position:0% +do that many ATS right to do most uh + + + align:start position:0% +do that many ATS right to do most uh +full size + + align:start position:0% +full size + + + align:start position:0% +full size +proteins um so that's a great problem um + + align:start position:0% +proteins um so that's a great problem um + + + align:start position:0% +proteins um so that's a great problem um +to study with classical models um for + + align:start position:0% +to study with classical models um for + + + align:start position:0% +to study with classical models um for +crystals like the two atom silicon eight + + align:start position:0% +crystals like the two atom silicon eight + + + align:start position:0% +crystals like the two atom silicon eight +electrons or all those crystals in there + + align:start position:0% +electrons or all those crystals in there + + + align:start position:0% +electrons or all those crystals in there +and up to say a thousand electrons um + + align:start position:0% +and up to say a thousand electrons um + + + align:start position:0% +and up to say a thousand electrons um +you can do things like calculate the + + align:start position:0% +you can do things like calculate the + + + align:start position:0% +you can do things like calculate the +change in the lattice with uh change in + + align:start position:0% +change in the lattice with uh change in + + + align:start position:0% +change in the lattice with uh change in +energy with lattice and from that um + + align:start position:0% +energy with lattice and from that um + + + align:start position:0% +energy with lattice and from that um +well this is the volume right but that's + + align:start position:0% +well this is the volume right but that's + + + align:start position:0% +well this is the volume right but that's +just the same as the change in the + + align:start position:0% +just the same as the change in the + + + align:start position:0% +just the same as the change in the +lattice and um and from from that second + + align:start position:0% +lattice and um and from from that second + + + align:start position:0% +lattice and um and from from that second +derivative you can get the bulk modulus + + align:start position:0% +derivative you can get the bulk modulus + + + align:start position:0% +derivative you can get the bulk modulus +which is a very important property + + align:start position:0% +which is a very important property + + + align:start position:0% +which is a very important property +um okay and this is something I just + + align:start position:0% +um okay and this is something I just + + + align:start position:0% +um okay and this is something I just +went through this was that slide that I + + align:start position:0% +went through this was that slide that I + + + align:start position:0% +went through this was that slide that I +talked about but it was really should + + align:start position:0% +talked about but it was really should + + + align:start position:0% +talked about but it was really should +have been an internal discussion um and + + align:start position:0% +have been an internal discussion um and + + + align:start position:0% +have been an internal discussion um and +and where you you know you find the + + align:start position:0% +and where you you know you find the + + + align:start position:0% +and where you you know you find the +converg ground state density and + + align:start position:0% +converg ground state density and + + + align:start position:0% +converg ground state density and +potential with some kpoint mesh that you + + align:start position:0% +potential with some kpoint mesh that you + + + align:start position:0% +potential with some kpoint mesh that you +gave it that's what you input is the K + + align:start position:0% +gave it that's what you input is the K + + + align:start position:0% +gave it that's what you input is the K +points that go into that calculation and + + align:start position:0% +points that go into that calculation and + + + align:start position:0% +points that go into that calculation and +then for that you calculate the energies + + align:start position:0% +then for that you calculate the energies + + + align:start position:0% +then for that you calculate the energies +that K points along all the lines and + + align:start position:0% +that K points along all the lines and + + + align:start position:0% +that K points along all the lines and +some software well step three is not + + align:start position:0% +some software well step three is not + + + align:start position:0% +some software well step three is not +really a step right but use some + + align:start position:0% +really a step right but use some + + + align:start position:0% +really a step right but use some +software to plot it okay and you can + + align:start position:0% +software to plot it okay and you can + + + align:start position:0% +software to plot it okay and you can +download the data for this from the + + align:start position:0% +download the data for this from the + + + align:start position:0% +download the data for this from the +nanohub there's a I've been showing you + + align:start position:0% +nanohub there's a I've been showing you + + + align:start position:0% +nanohub there's a I've been showing you +the version of the plot that gives you + + align:start position:0% +the version of the plot that gives you + + + align:start position:0% +the version of the plot that gives you +the Greek characters which is an image + + align:start position:0% +the Greek characters which is an image + + + align:start position:0% +the Greek characters which is an image +but there's another version that gives + + align:start position:0% +but there's another version that gives + + + align:start position:0% +but there's another version that gives +you the raw data it just doesn't put the + + align:start position:0% +you the raw data it just doesn't put the + + + align:start position:0% +you the raw data it just doesn't put the +characters on it but that will allow you + + align:start position:0% +characters on it but that will allow you + + + align:start position:0% +characters on it but that will allow you +to compare one run to another and + + align:start position:0% +to compare one run to another and + + + align:start position:0% +to compare one run to another and +download the raw + + align:start position:0% +download the raw + + + align:start position:0% +download the raw +data and then um calculating the Doss is + + align:start position:0% +data and then um calculating the Doss is + + + align:start position:0% +data and then um calculating the Doss is +um um is also a two-step process you + + align:start position:0% +um um is also a two-step process you + + + align:start position:0% +um um is also a two-step process you +converge the ground state density and + + align:start position:0% +converge the ground state density and + + + align:start position:0% +converge the ground state density and +potential and then you use that + + align:start position:0% +potential and then you use that + + + align:start position:0% +potential and then you use that +potential to calculate the energies and + + align:start position:0% +potential to calculate the energies and + + + align:start position:0% +potential to calculate the energies and +usually you want to do this at a dense K + + align:start position:0% +usually you want to do this at a dense K + + + align:start position:0% +usually you want to do this at a dense K +mesh because the subtle variations see + + align:start position:0% +mesh because the subtle variations see + + + align:start position:0% +mesh because the subtle variations see +in a in a + + align:start position:0% +in a in a + + + align:start position:0% +in a in a +molecule often times the Dos is is + + align:start position:0% +molecule often times the Dos is is + + + align:start position:0% +molecule often times the Dos is is +pretty clear you know I mean if I turn + + align:start position:0% + + + + align:start position:0% + +um oh I guess I could have just done + + align:start position:0% +um oh I guess I could have just done + + + align:start position:0% +um oh I guess I could have just done +this look at that if I turn um if I turn + + align:start position:0% +this look at that if I turn um if I turn + + + align:start position:0% +this look at that if I turn um if I turn +say an atom or a molecule on its side + + align:start position:0% +say an atom or a molecule on its side + + + align:start position:0% +say an atom or a molecule on its side +then I have this and you use some kind + + align:start position:0% +then I have this and you use some kind + + + align:start position:0% +then I have this and you use some kind +of you know smearing function and so + + align:start position:0% +of you know smearing function and so + + + align:start position:0% +of you know smearing function and so +your well that was a bad centering and + + align:start position:0% +your well that was a bad centering and + + + align:start position:0% +your well that was a bad centering and +so your Doss would look like that right + + align:start position:0% +so your Doss would look like that right + + + align:start position:0% +so your Doss would look like that right +but there'd be bigger Peaks where you + + align:start position:0% +but there'd be bigger Peaks where you + + + align:start position:0% +but there'd be bigger Peaks where you +have like lots of states and smaller + + align:start position:0% +have like lots of states and smaller + + + align:start position:0% +have like lots of states and smaller +Peaks where you don't have many but you + + align:start position:0% +Peaks where you don't have many but you + + + align:start position:0% +Peaks where you don't have many but you +see now I'm turning a band structure and + + align:start position:0% +see now I'm turning a band structure and + + + align:start position:0% +see now I'm turning a band structure and +you saw Alpha quartz right so now I'm + + align:start position:0% +you saw Alpha quartz right so now I'm + + + align:start position:0% +you saw Alpha quartz right so now I'm +turning um see if I I can just show it + + align:start position:0% +turning um see if I I can just show it + + + align:start position:0% +turning um see if I I can just show it +one more + + align:start position:0% +one more + + + align:start position:0% +one more +time oh man seriously oh it was in + + align:start position:0% +time oh man seriously oh it was in + + + align:start position:0% +time oh man seriously oh it was in +another right I'm turning this on its + + align:start position:0% +another right I'm turning this on its + + + align:start position:0% +another right I'm turning this on its +side now and that's uh not as easy right + + align:start position:0% +side now and that's uh not as easy right + + + align:start position:0% +side now and that's uh not as easy right +that's trickier so there's different + + align:start position:0% +that's trickier so there's different + + + align:start position:0% +that's trickier so there's different +weights of a band at different parts in + + align:start position:0% +weights of a band at different parts in + + + align:start position:0% +weights of a band at different parts in +energy and when I turn this on the side + + align:start position:0% +energy and when I turn this on the side + + + align:start position:0% +energy and when I turn this on the side +you can get um Doss uh shapes density of + + align:start position:0% +you can get um Doss uh shapes density of + + + align:start position:0% +you can get um Doss uh shapes density of +states that are um that have a you know + + align:start position:0% +states that are um that have a you know + + + align:start position:0% +states that are um that have a you know +more sort of features in them and to get + + align:start position:0% +more sort of features in them and to get + + + align:start position:0% +more sort of features in them and to get +all those features just right um You + + align:start position:0% +all those features just right um You + + + align:start position:0% +all those features just right um You +need to use the dense kpoint mesh which + + align:start position:0% +need to use the dense kpoint mesh which + + + align:start position:0% +need to use the dense kpoint mesh which +is what the code does okay um this can + + align:start position:0% +is what the code does okay um this can + + + align:start position:0% +is what the code does okay um this can +be measured the Doss can be measured + + align:start position:0% +be measured the Doss can be measured + + + align:start position:0% +be measured the Doss can be measured +right + + align:start position:0% +right + + + align:start position:0% +right +experimentally right you can use STM to + + align:start position:0% +experimentally right you can use STM to + + + align:start position:0% +experimentally right you can use STM to +actually directly measure the + + align:start position:0% +actually directly measure the + + + align:start position:0% +actually directly measure the +Doss + + align:start position:0% +Doss + + + align:start position:0% +Doss +okay and we talked about this already + + align:start position:0% +okay and we talked about this already + + + align:start position:0% +okay and we talked about this already +you fill up your electrons to the + + align:start position:0% +you fill up your electrons to the + + + align:start position:0% +you fill up your electrons to the +firming level um if there's any bands + + align:start position:0% +firming level um if there's any bands + + + align:start position:0% +firming level um if there's any bands +Crossing it's a metal if not it's an + + align:start position:0% +Crossing it's a metal if not it's an + + + align:start position:0% +Crossing it's a metal if not it's an +insulator or a semiconductor if you have + + align:start position:0% +insulator or a semiconductor if you have + + + align:start position:0% +insulator or a semiconductor if you have +an odd number of electrons in the unit + + align:start position:0% +an odd number of electrons in the unit + + + align:start position:0% +an odd number of electrons in the unit +cell it it um it has to be a metal + + align:start position:0% +cell it it um it has to be a metal + + + align:start position:0% +cell it it um it has to be a metal +because the firming level is going to + + align:start position:0% +because the firming level is going to + + + align:start position:0% +because the firming level is going to +come in you know in the middle each band + + align:start position:0% +come in you know in the middle each band + + + align:start position:0% +come in you know in the middle each band +takes two electrons so if you fill up to + + align:start position:0% +takes two electrons so if you fill up to + + + align:start position:0% +takes two electrons so if you fill up to +the firmy level and the firmy level is + + align:start position:0% +the firmy level and the firmy level is + + + align:start position:0% +the firmy level and the firmy level is +in the middle of a band by definition + + align:start position:0% +in the middle of a band by definition + + + align:start position:0% +in the middle of a band by definition +it's a metal right + + align:start position:0% +it's a metal right + + + align:start position:0% +it's a metal right +okay okay + + align:start position:0% +okay okay + + + align:start position:0% +okay okay +sodium um and then here's a picture of + + align:start position:0% +sodium um and then here's a picture of + + + align:start position:0% +sodium um and then here's a picture of +diamond and the thing that I want to um + + align:start position:0% +diamond and the thing that I want to um + + + align:start position:0% +diamond and the thing that I want to um +again emphasize is that from + + align:start position:0% +again emphasize is that from + + + align:start position:0% +again emphasize is that from +DFT uh + + align:start position:0% +DFT uh + + + align:start position:0% +DFT uh +these characters of these Wiggles and of + + align:start position:0% +these characters of these Wiggles and of + + + align:start position:0% +these characters of these Wiggles and of +these features are pretty darn good but + + align:start position:0% +these features are pretty darn good but + + + align:start position:0% +these features are pretty darn good but +this distance is not and so we what + + align:start position:0% +this distance is not and so we what + + + align:start position:0% +this distance is not and so we what +we're going to do in this + + align:start position:0% +we're going to do in this + + + align:start position:0% +we're going to do in this +class and we're going to be proud about + + align:start position:0% +class and we're going to be proud about + + + align:start position:0% +class and we're going to be proud about +it is we're going to just shift these + + align:start position:0% +it is we're going to just shift these + + + align:start position:0% +it is we're going to just shift these +bands up by a rigid amount to fix the + + align:start position:0% +bands up by a rigid amount to fix the + + + align:start position:0% +bands up by a rigid amount to fix the +Gap that was probably electron volts + + align:start position:0% +Gap that was probably electron volts + + + align:start position:0% +Gap that was probably electron volts +yeah it says it here e electron volts + + align:start position:0% +yeah it says it here e electron volts + + + align:start position:0% +yeah it says it here e electron volts +and here + + align:start position:0% +and here + + + align:start position:0% +and here +um it looks like what do we have like a + + align:start position:0% +um it looks like what do we have like a + + + align:start position:0% +um it looks like what do we have like a +3 EV 3 EV Gap from DFT and so that's + + align:start position:0% +3 EV 3 EV Gap from DFT and so that's + + + align:start position:0% +3 EV 3 EV Gap from DFT and so that's +about half very often DFT gives you a + + align:start position:0% +about half very often DFT gives you a + + + align:start position:0% +about half very often DFT gives you a +gap that's about half of the + + align:start position:0% +gap that's about half of the + + + align:start position:0% +gap that's about half of the +experimental Gap very often not at all + + align:start position:0% +experimental Gap very often not at all + + + align:start position:0% +experimental Gap very often not at all +always but very + + align:start position:0% +always but very + + + align:start position:0% +always but very +often for germanium it makes it a semi + + align:start position:0% +often for germanium it makes it a semi + + + align:start position:0% +often for germanium it makes it a semi +metal which it's not does anybody know + + align:start position:0% +metal which it's not does anybody know + + + align:start position:0% +metal which it's not does anybody know +what a semi metal is + + align:start position:0% + + + + align:start position:0% + +not + + align:start position:0% + + + + align:start position:0% + +quite here's a here's an indirect band + + align:start position:0% +quite here's a here's an indirect band + + + align:start position:0% +quite here's a here's an indirect band +Gap a semi metal is a cool material + + align:start position:0% +Gap a semi metal is a cool material + + + align:start position:0% +Gap a semi metal is a cool material +geranium is not a semimetal but DFT will + + align:start position:0% +geranium is not a semimetal but DFT will + + + align:start position:0% +geranium is not a semimetal but DFT will +tell you it is because of the Gap + + align:start position:0% +tell you it is because of the Gap + + + align:start position:0% +tell you it is because of the Gap +problem um here's an indirect bandap + + align:start position:0% +problem um here's an indirect bandap + + + align:start position:0% +problem um here's an indirect bandap +material which one is + + align:start position:0% +material which one is + + + align:start position:0% +material which one is +it yeah sure why + + align:start position:0% +it yeah sure why + + + align:start position:0% +it yeah sure why +not okay and if it's silicon this will + + align:start position:0% +not okay and if it's silicon this will + + + align:start position:0% +not okay and if it's silicon this will +be 1.1 EV in + + align:start position:0% +be 1.1 EV in + + + align:start position:0% +be 1.1 EV in +experiment and about 0.6 EV + + align:start position:0% +experiment and about 0.6 EV + + + align:start position:0% +experiment and about 0.6 EV +in + + align:start position:0% + + + + align:start position:0% + +DFT okay and that's the band Gap error + + align:start position:0% +DFT okay and that's the band Gap error + + + align:start position:0% +DFT okay and that's the band Gap error +but again you can shift it and that's + + align:start position:0% +but again you can shift it and that's + + + align:start position:0% +but again you can shift it and that's +what we're going to do we're going to be + + align:start position:0% +what we're going to do we're going to be + + + align:start position:0% +what we're going to do we're going to be +okay with that um in uh if you switch to + + align:start position:0% +okay with that um in uh if you switch to + + + align:start position:0% +okay with that um in uh if you switch to +geranium experiment says it's about A6 + + align:start position:0% +geranium experiment says it's about A6 + + + align:start position:0% +geranium experiment says it's about A6 +or 7 EV Gap something around there but + + align:start position:0% +or 7 EV Gap something around there but + + + align:start position:0% +or 7 EV Gap something around there but +DFT um that's silicon okay but DFT will + + align:start position:0% +DFT um that's silicon okay but DFT will + + + align:start position:0% +DFT um that's silicon okay but DFT will +put it here it'll put this conduction + + align:start position:0% +put it here it'll put this conduction + + + align:start position:0% +put it here it'll put this conduction +band below + + align:start position:0% + + + + align:start position:0% + +right it has to actually it's why didn't + + align:start position:0% +right it has to actually it's why didn't + + + align:start position:0% +right it has to actually it's why didn't +I draw that right it's actually um comes + + align:start position:0% +I draw that right it's actually um comes + + + align:start position:0% +I draw that right it's actually um comes +below + + align:start position:0% +below + + + align:start position:0% +below +so that is a semi + + align:start position:0% + + + + align:start position:0% + +metal when you have uh basically it's + + align:start position:0% +metal when you have uh basically it's + + + align:start position:0% +metal when you have uh basically it's +Crossings okay across the firmy level + + align:start position:0% +Crossings okay across the firmy level + + + align:start position:0% +Crossings okay across the firmy level +but in an indirect from indirect States + + align:start position:0% +but in an indirect from indirect States + + + align:start position:0% +but in an indirect from indirect States +right that's called the semi metal and + + align:start position:0% +right that's called the semi metal and + + + align:start position:0% +right that's called the semi metal and +DFT will tell you geranium is that which + + align:start position:0% +DFT will tell you geranium is that which + + + align:start position:0% +DFT will tell you geranium is that which +is not but you you can still shift all + + align:start position:0% +is not but you you can still shift all + + + align:start position:0% +is not but you you can still shift all +those States up which we do okay oh + + align:start position:0% +those States up which we do okay oh + + + align:start position:0% +those States up which we do okay oh +there's a metal oh look at that + + align:start position:0% +there's a metal oh look at that + + + align:start position:0% +there's a metal oh look at that +spaghetti you now know oh and there it + + align:start position:0% +spaghetti you now know oh and there it + + + align:start position:0% +spaghetti you now know oh and there it +is see often in papers you'll see in the + + align:start position:0% +is see often in papers you'll see in the + + + align:start position:0% +is see often in papers you'll see in the +literature so you now becoming sort of + + align:start position:0% +literature so you now becoming sort of + + + align:start position:0% +literature so you now becoming sort of +experts at seeing a band structure and + + align:start position:0% +experts at seeing a band structure and + + + align:start position:0% +experts at seeing a band structure and +seeing it really seeing it you know and + + align:start position:0% +seeing it really seeing it you know and + + + align:start position:0% +seeing it really seeing it you know and +it's a powerful thing and there it is + + align:start position:0% +it's a powerful thing and there it is + + + align:start position:0% +it's a powerful thing and there it is +with the Doss next to it you see because + + align:start position:0% +with the Doss next to it you see because + + + align:start position:0% +with the Doss next to it you see because +that's just this on the side which is + + align:start position:0% +that's just this on the side which is + + + align:start position:0% +that's just this on the side which is +why you then plot the Doss sideways + + align:start position:0% + + + + align:start position:0% + +often um except that doesn't quite look + + align:start position:0% +often um except that doesn't quite look + + + align:start position:0% +often um except that doesn't quite look +right but anyway + + align:start position:0% +right but anyway + + + align:start position:0% +right but anyway +um oh maybe this + + align:start position:0% +um oh maybe this + + + align:start position:0% +um oh maybe this +yeah that's what it should + + align:start position:0% +yeah that's what it should + + + align:start position:0% +yeah that's what it should +be + + align:start position:0% +be + + + align:start position:0% +be +okay um and then you know we've we've + + align:start position:0% +okay um and then you know we've we've + + + align:start position:0% +okay um and then you know we've we've +talked about this and we're going to + + align:start position:0% +talked about this and we're going to + + + align:start position:0% +talked about this and we're going to +talk about this um we're going to come + + align:start position:0% +talk about this um we're going to come + + + align:start position:0% +talk about this um we're going to come +back to this a little bit when we talk + + align:start position:0% +back to this a little bit when we talk + + + align:start position:0% +back to this a little bit when we talk +about solar cells um but I have + + align:start position:0% +about solar cells um but I have + + + align:start position:0% +about solar cells um but I have +mentioned this a bunch certainly this + + align:start position:0% +mentioned this a bunch certainly this + + + align:start position:0% +mentioned this a bunch certainly this +would be a a good third homework set um + + align:start position:0% +would be a a good third homework set um + + + align:start position:0% +would be a a good third homework set um +is to think about this you know indirect + + align:start position:0% +is to think about this you know indirect + + + align:start position:0% +is to think about this you know indirect +versus direct bandap problem somebody + + align:start position:0% +versus direct bandap problem somebody + + + align:start position:0% +versus direct bandap problem somebody +tell me again why silicon solar cells + + align:start position:0% +tell me again why silicon solar cells + + + align:start position:0% +tell me again why silicon solar cells +are expensive just so I can go home + + align:start position:0% +are expensive just so I can go home + + + align:start position:0% +are expensive just so I can go home +today and feel really + + align:start position:0% +today and feel really + + + align:start position:0% +today and feel really +good or really bad because it's bad + + align:start position:0% +good or really bad because it's bad + + + align:start position:0% +good or really bad because it's bad +news yeah but why is that why does that + + align:start position:0% +news yeah but why is that why does that + + + align:start position:0% +news yeah but why is that why does that +make silicon solar cells + + align:start position:0% + + + + align:start position:0% + +expensive why do you have to make them + + align:start position:0% + + + + align:start position:0% + +thick yeah because you got to get you + + align:start position:0% +thick yeah because you got to get you + + + align:start position:0% +thick yeah because you got to get you +see you got to get I think I had it + + align:start position:0% +see you got to get I think I had it + + + align:start position:0% +see you got to get I think I had it +shown here yeah yeah see that's easy for + + align:start position:0% +shown here yeah yeah see that's easy for + + + align:start position:0% +shown here yeah yeah see that's easy for +a photon to do right I've talked about + + align:start position:0% +a photon to do right I've talked about + + + align:start position:0% +a photon to do right I've talked about +this now here is in the cartoon that's + + align:start position:0% +this now here is in the cartoon that's + + + align:start position:0% +this now here is in the cartoon that's +easy for a photon to do okay um that's + + align:start position:0% +easy for a photon to do okay um that's + + + align:start position:0% +easy for a photon to do okay um that's +easy for a photon to do at different + + align:start position:0% +easy for a photon to do at different + + + align:start position:0% +easy for a photon to do at different +places in energy and this would be + + align:start position:0% +places in energy and this would be + + + align:start position:0% +places in energy and this would be +absorbing light these blue arrows would + + align:start position:0% +absorbing light these blue arrows would + + + align:start position:0% +absorbing light these blue arrows would +be the light that come from the solar + + align:start position:0% +be the light that come from the solar + + + align:start position:0% +be the light that come from the solar +flux that you're downloading in your + + align:start position:0% +flux that you're downloading in your + + + align:start position:0% +flux that you're downloading in your +homework right that's where these blue + + align:start position:0% +homework right that's where these blue + + + align:start position:0% +homework right that's where these blue +arrows come um and it's easy for those + + align:start position:0% +arrows come um and it's easy for those + + + align:start position:0% +arrows come um and it's easy for those +blue arrows to do this but to see the + + align:start position:0% +blue arrows to do this but to see the + + + align:start position:0% +blue arrows to do this but to see the +thing that matters is this minimum + + align:start position:0% +thing that matters is this minimum + + + align:start position:0% +thing that matters is this minimum +amount of energy the band gap of the + + align:start position:0% +amount of energy the band gap of the + + + align:start position:0% +amount of energy the band gap of the +material uh that is the lowest amount of + + align:start position:0% +material uh that is the lowest amount of + + + align:start position:0% +material uh that is the lowest amount of +energy that it would take to get an + + align:start position:0% +energy that it would take to get an + + + align:start position:0% +energy that it would take to get an +electron up from the valance into the + + align:start position:0% +electron up from the valance into the + + + align:start position:0% +electron up from the valance into the +conduction bands and that in this case + + align:start position:0% +conduction bands and that in this case + + + align:start position:0% +conduction bands and that in this case +is not vertical it's not vertical it's + + align:start position:0% +is not vertical it's not vertical it's + + + align:start position:0% +is not vertical it's not vertical it's +an indirect Gap did I have it there um + + align:start position:0% +an indirect Gap did I have it there um + + + align:start position:0% +an indirect Gap did I have it there um +and because of that it's not very good + + align:start position:0% +and because of that it's not very good + + + align:start position:0% +and because of that it's not very good +at absorbing light those photons those + + align:start position:0% +at absorbing light those photons those + + + align:start position:0% +at absorbing light those photons those +blue + + align:start position:0% +blue + + + align:start position:0% +blue +lines um let just get them back here + + align:start position:0% +lines um let just get them back here + + + align:start position:0% +lines um let just get them back here +those blue lines they need help + + align:start position:0% +those blue lines they need help + + + align:start position:0% +those blue lines they need help +help they can do this but they can't do + + align:start position:0% +help they can do this but they can't do + + + align:start position:0% +help they can do this but they can't do +this and to do this you need help okay + + align:start position:0% +this and to do this you need help okay + + + align:start position:0% +this and to do this you need help okay +so you need some kind of uh kick and + + align:start position:0% +so you need some kind of uh kick and + + + align:start position:0% +so you need some kind of uh kick and +that means it's a much less efficient + + align:start position:0% +that means it's a much less efficient + + + align:start position:0% +that means it's a much less efficient +process and absorbing light in that + + align:start position:0% +process and absorbing light in that + + + align:start position:0% +process and absorbing light in that +whole region of the spectrum where a + + align:start position:0% +whole region of the spectrum where a + + + align:start position:0% +whole region of the spectrum where a +photon would need to do this that whole + + align:start position:0% +photon would need to do this that whole + + + align:start position:0% +photon would need to do this that whole +region is very inefficient and yet + + align:start position:0% +region is very inefficient and yet + + + align:start position:0% +region is very inefficient and yet +that's where the sun is that's where the + + align:start position:0% +that's where the sun is that's where the + + + align:start position:0% +that's where the sun is that's where the +sun is and so you got to make them + + align:start position:0% +sun is and so you got to make them + + + align:start position:0% +sun is and so you got to make them +really thick it's inefficient but not + + align:start position:0% +really thick it's inefficient but not + + + align:start position:0% +really thick it's inefficient but not +zero so you make them really thick so + + align:start position:0% +zero so you make them really thick so + + + align:start position:0% +zero so you make them really thick so +you get that region of the Sun but to + + align:start position:0% +you get that region of the Sun but to + + + align:start position:0% +you get that region of the Sun but to +make them really thick um you see you're + + align:start position:0% +make them really thick um you see you're + + + align:start position:0% +make them really thick um you see you're +generating electrons in + + align:start position:0% +generating electrons in + + + align:start position:0% +generating electrons in +holes and those that generation of + + align:start position:0% +holes and those that generation of + + + align:start position:0% +holes and those that generation of +electrons and holes well that then you + + align:start position:0% +electrons and holes well that then you + + + align:start position:0% +electrons and holes well that then you +got to get them + + align:start position:0% +got to get them + + + align:start position:0% +got to get them +out right you can't just let them stay + + align:start position:0% +out right you can't just let them stay + + + align:start position:0% +out right you can't just let them stay +there and to get them out well you need + + align:start position:0% +there and to get them out well you need + + + align:start position:0% +there and to get them out well you need +a good + + align:start position:0% +a good + + + align:start position:0% +a good +material and if they have to go a long + + align:start position:0% +material and if they have to go a long + + + align:start position:0% +material and if they have to go a long +ways to get out which they do because + + align:start position:0% +ways to get out which they do because + + + align:start position:0% +ways to get out which they do because +they have to make it so thick because it + + align:start position:0% +they have to make it so thick because it + + + align:start position:0% +they have to make it so thick because it +doesn't absorb light well because of the + + align:start position:0% +doesn't absorb light well because of the + + + align:start position:0% +doesn't absorb light well because of the +band structure + + align:start position:0% +band structure + + + align:start position:0% +band structure +then um where was I again no then you uh + + align:start position:0% +then um where was I again no then you uh + + + align:start position:0% +then um where was I again no then you uh +you need it to be a really pure material + + align:start position:0% +you need it to be a really pure material + + + align:start position:0% +you need it to be a really pure material +that costs money okay otherwise they'll + + align:start position:0% +that costs money okay otherwise they'll + + + align:start position:0% +that costs money okay otherwise they'll +run into traps and and other things so + + align:start position:0% +run into traps and and other things so + + + align:start position:0% +run into traps and and other things so +what we're going to do is on Thursday + + align:start position:0% +what we're going to do is on Thursday + + + align:start position:0% +what we're going to do is on Thursday +we'll talk a little bit more about um + + align:start position:0% +we'll talk a little bit more about um + + + align:start position:0% +we'll talk a little bit more about um +some other properties we'll talk about + + align:start position:0% +some other properties we'll talk about + + + align:start position:0% +some other properties we'll talk about +magnetism very briefly show you that you + + align:start position:0% +magnetism very briefly show you that you + + + align:start position:0% +magnetism very briefly show you that you +can do molecular Dynamics um couple + + align:start position:0% +can do molecular Dynamics um couple + + + align:start position:0% +can do molecular Dynamics um couple +other things and then we'll start + + align:start position:0% +other things and then we'll start + + + align:start position:0% +other things and then we'll start +turning our attention to solar cells + + align:start position:0% +turning our attention to solar cells + + + align:start position:0% +turning our attention to solar cells +okay for \ No newline at end of file diff --git a/GLVrOlHLJ1U.txt b/GLVrOlHLJ1U.txt new file mode 100644 index 0000000000000000000000000000000000000000..5beb2e215ca50f2a9e2af98636191be358ff42e0 --- /dev/null +++ b/GLVrOlHLJ1U.txt @@ -0,0 +1,13035 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT OpenCourseWare continue to + + align:start position:0% +will help MIT OpenCourseWare continue to + + + align:start position:0% +will help MIT OpenCourseWare continue to +offer high quality educational resources + + align:start position:0% +offer high quality educational resources + + + align:start position:0% +offer high quality educational resources +for free + + align:start position:0% +for free + + + align:start position:0% +for free +to make a donation or to view additional + + align:start position:0% +to make a donation or to view additional + + + align:start position:0% +to make a donation or to view additional +materials from hundreds of MIT courses + + align:start position:0% +materials from hundreds of MIT courses + + + align:start position:0% +materials from hundreds of MIT courses +visit MIT opencourseware at ocw.mit.edu + + align:start position:0% + + + + align:start position:0% + +thank you again for all being here we + + align:start position:0% +thank you again for all being here we + + + align:start position:0% +thank you again for all being here we +were gonna talk a little bit about the + + align:start position:0% +were gonna talk a little bit about the + + + align:start position:0% +were gonna talk a little bit about the +challenges of blockchain technology + + align:start position:0% +challenges of blockchain technology + + + align:start position:0% +challenges of blockchain technology +I'm apologizing in advance I'm supposed + + align:start position:0% +I'm apologizing in advance I'm supposed + + + align:start position:0% +I'm apologizing in advance I'm supposed +to be like across campus for a 4:00 + + align:start position:0% +to be like across campus for a 4:00 + + + align:start position:0% +to be like across campus for a 4:00 +o'clock meeting so I won't have much + + align:start position:0% +o'clock meeting so I won't have much + + + align:start position:0% +o'clock meeting so I won't have much +time right at the end to do the little + + align:start position:0% +time right at the end to do the little + + + align:start position:0% +time right at the end to do the little +rap with students coming up I will note + + align:start position:0% +rap with students coming up I will note + + + align:start position:0% +rap with students coming up I will note +also that if you want to come see me I'm + + align:start position:0% +also that if you want to come see me I'm + + + align:start position:0% +also that if you want to come see me I'm +open to it next week's a great week by + + align:start position:0% +open to it next week's a great week by + + + align:start position:0% +open to it next week's a great week by +the way cuz I'm here all four or five + + align:start position:0% +the way cuz I'm here all four or five + + + align:start position:0% +the way cuz I'm here all four or five +days but I don't have set office hours + + align:start position:0% +days but I don't have set office hours + + + align:start position:0% +days but I don't have set office hours +just email me copy Dylan who's the new + + align:start position:0% +just email me copy Dylan who's the new + + + align:start position:0% +just email me copy Dylan who's the new +course administrator there was a swap + + align:start position:0% +course administrator there was a swap + + + align:start position:0% +course administrator there was a swap +out from Ryan or copy Toledo or Sabrina + + align:start position:0% +out from Ryan or copy Toledo or Sabrina + + + align:start position:0% +out from Ryan or copy Toledo or Sabrina +or something but just shoot me an email + + align:start position:0% +or something but just shoot me an email + + + align:start position:0% +or something but just shoot me an email +and then I'll set something up with you + + align:start position:0% +and then I'll set something up with you + + + align:start position:0% +and then I'll set something up with you +if you want to follow up either on your + + align:start position:0% +if you want to follow up either on your + + + align:start position:0% +if you want to follow up either on your +projects or it's a question about + + align:start position:0% +projects or it's a question about + + + align:start position:0% +projects or it's a question about +anything around blockchain I also want + + align:start position:0% +anything around blockchain I also want + + + align:start position:0% +anything around blockchain I also want +to thank we don't usually have people + + align:start position:0% +to thank we don't usually have people + + + align:start position:0% +to thank we don't usually have people +here with jackets on but we have six or + + align:start position:0% +here with jackets on but we have six or + + + align:start position:0% +here with jackets on but we have six or +eight veterans who have served our + + align:start position:0% +eight veterans who have served our + + + align:start position:0% +eight veterans who have served our +country and I thank you for your service + + align:start position:0% + + + + align:start position:0% + +they're here to observe us I I don't + + align:start position:0% +they're here to observe us I I don't + + + align:start position:0% +they're here to observe us I I don't +know whether we'll scare them away or + + align:start position:0% +know whether we'll scare them away or + + + align:start position:0% +know whether we'll scare them away or +not but thank you for for joining us + + align:start position:0% +not but thank you for for joining us + + + align:start position:0% +not but thank you for for joining us +so today's topics are gonna be around of + + align:start position:0% +so today's topics are gonna be around of + + + align:start position:0% +so today's topics are gonna be around of +course we're gonna go through the + + align:start position:0% +course we're gonna go through the + + + align:start position:0% +course we're gonna go through the +readings a little bit we don't have + + align:start position:0% +readings a little bit we don't have + + + align:start position:0% +readings a little bit we don't have +Larry lesyk and it's a little bit more + + align:start position:0% +Larry lesyk and it's a little bit more + + + align:start position:0% +Larry lesyk and it's a little bit more +relaxed so I might be doing some cold + + align:start position:0% +relaxed so I might be doing some cold + + + align:start position:0% +relaxed so I might be doing some cold +calling if that's alright I'm gonna go + + align:start position:0% +calling if that's alright I'm gonna go + + + align:start position:0% +calling if that's alright I'm gonna go +back a little bit to the technical + + align:start position:0% +back a little bit to the technical + + + align:start position:0% +back a little bit to the technical +features in a quick wrap in two slides + + align:start position:0% +features in a quick wrap in two slides + + + align:start position:0% +features in a quick wrap in two slides +or three slides but I just want to do + + align:start position:0% +or three slides but I just want to do + + + align:start position:0% +or three slides but I just want to do +that is the set up again and of course + + align:start position:0% +that is the set up again and of course + + + align:start position:0% +that is the set up again and of course +because you all love hash functions so + + align:start position:0% +because you all love hash functions so + + + align:start position:0% +because you all love hash functions so +much it's just a way to bring it back to + + align:start position:0% +much it's just a way to bring it back to + + + align:start position:0% +much it's just a way to bring it back to +some of the technical features to set up + + align:start position:0% +some of the technical features to set up + + + align:start position:0% +some of the technical features to set up +really what are some of the issues we + + align:start position:0% +really what are some of the issues we + + + align:start position:0% +really what are some of the issues we +have + + align:start position:0% +have + + + align:start position:0% +have +I think it's lecture eleven and twelve + + align:start position:0% +I think it's lecture eleven and twelve + + + align:start position:0% +I think it's lecture eleven and twelve +where it's just what I call Act two is + + align:start position:0% +where it's just what I call Act two is + + + align:start position:0% +where it's just what I call Act two is +the economics but I want to set up a + + align:start position:0% +the economics but I want to set up a + + + align:start position:0% +the economics but I want to set up a +little bit about the economics you saw + + align:start position:0% +little bit about the economics you saw + + + align:start position:0% +little bit about the economics you saw +that in the reading + + align:start position:0% +that in the reading + + + align:start position:0% +that in the reading +the xxi Geneva report that Simon Johnson + + align:start position:0% +the xxi Geneva report that Simon Johnson + + + align:start position:0% +the xxi Geneva report that Simon Johnson +and Nahan Narula and my Casey and Joan + + align:start position:0% +and Nahan Narula and my Casey and Joan + + + align:start position:0% +and Nahan Narula and my Casey and Joan +and I wrote so now you all + + align:start position:0% +and I wrote so now you all + + + align:start position:0% +and I wrote so now you all +I only assigned just seven pages out of + + align:start position:0% +I only assigned just seven pages out of + + + align:start position:0% +I only assigned just seven pages out of +it so I hope that your raid read the + + align:start position:0% +it so I hope that your raid read the + + + align:start position:0% +it so I hope that your raid read the +seven pages but some of the costs and + + align:start position:0% +seven pages but some of the costs and + + + align:start position:0% +seven pages but some of the costs and +trade-offs the challenges of blockchain + + align:start position:0% +trade-offs the challenges of blockchain + + + align:start position:0% +trade-offs the challenges of blockchain +technology that are very real I'll give + + align:start position:0% +technology that are very real I'll give + + + align:start position:0% +technology that are very real I'll give +you my own perspective on where I think + + align:start position:0% +you my own perspective on where I think + + + align:start position:0% +you my own perspective on where I think +this will sort out over the next three + + align:start position:0% +this will sort out over the next three + + + align:start position:0% +this will sort out over the next three +to ten years so I'll do some predictions + + align:start position:0% +to ten years so I'll do some predictions + + + align:start position:0% +to ten years so I'll do some predictions +Vitalik Bou Durant has also talked about + + align:start position:0% +Vitalik Bou Durant has also talked about + + + align:start position:0% +Vitalik Bou Durant has also talked about +a trilemma and I want to chat about that + + align:start position:0% +a trilemma and I want to chat about that + + + align:start position:0% +a trilemma and I want to chat about that +and that was one of the readings if I + + align:start position:0% +and that was one of the readings if I + + + align:start position:0% +and that was one of the readings if I +recall he's such a leader in this + + align:start position:0% +recall he's such a leader in this + + + align:start position:0% +recall he's such a leader in this +community that when he writes and says + + align:start position:0% +community that when he writes and says + + + align:start position:0% +community that when he writes and says +something like this it was relevant I + + align:start position:0% +something like this it was relevant I + + + align:start position:0% +something like this it was relevant I +think that everybody's understand what + + align:start position:0% +think that everybody's understand what + + + align:start position:0% +think that everybody's understand what +Vitalik bitter ends kind of trilemma as + + align:start position:0% +Vitalik bitter ends kind of trilemma as + + + align:start position:0% +Vitalik bitter ends kind of trilemma as +even though that some people think he's + + align:start position:0% +even though that some people think he's + + + align:start position:0% +even though that some people think he's +mistaken some possible solutions to this + + align:start position:0% +mistaken some possible solutions to this + + + align:start position:0% +mistaken some possible solutions to this +we have who's attending today + + align:start position:0% +we have who's attending today + + + align:start position:0% +we have who's attending today +Amador's who was actually one of the + + align:start position:0% +Amador's who was actually one of the + + + align:start position:0% +Amador's who was actually one of the +developers on some of the solutions + + align:start position:0% +developers on some of the solutions + + + align:start position:0% +developers on some of the solutions +around zero knowledge proof sand he + + align:start position:0% +around zero knowledge proof sand he + + + align:start position:0% +around zero knowledge proof sand he +might get caught on he works over the + + align:start position:0% +might get caught on he works over the + + + align:start position:0% +might get caught on he works over the +digital currency initiative I'm hope + + align:start position:0% +digital currency initiative I'm hope + + + align:start position:0% +digital currency initiative I'm hope +you're ready and and why I think + + align:start position:0% +you're ready and and why I think + + + align:start position:0% +you're ready and and why I think +governance is the most challenging piece + + align:start position:0% +governance is the most challenging piece + + + align:start position:0% +governance is the most challenging piece +so with that the readings I have a list + + align:start position:0% +so with that the readings I have a list + + + align:start position:0% +so with that the readings I have a list +of everybody that hasn't spoken yet so + + align:start position:0% +of everybody that hasn't spoken yet so + + + align:start position:0% +of everybody that hasn't spoken yet so +the goal is to speak that's what class + + align:start position:0% +the goal is to speak that's what class + + + align:start position:0% +the goal is to speak that's what class +participation is like I'm gonna be + + align:start position:0% +participation is like I'm gonna be + + + align:start position:0% +participation is like I'm gonna be +light-hearted about it I it's not that + + align:start position:0% +light-hearted about it I it's not that + + + align:start position:0% +light-hearted about it I it's not that +long ago I was a student really I + + align:start position:0% +long ago I was a student really I + + + align:start position:0% +long ago I was a student really I +remember all this you know you want to + + align:start position:0% +remember all this you know you want to + + + align:start position:0% +remember all this you know you want to +get your name off this list just just + + align:start position:0% +get your name off this list just just + + + align:start position:0% +get your name off this list just just +what I say that kind of encouraging so + + align:start position:0% +what I say that kind of encouraging so + + + align:start position:0% +what I say that kind of encouraging so +should I do it alphabetical from the + + align:start position:0% +should I do it alphabetical from the + + + align:start position:0% +should I do it alphabetical from the +list as to who wants to tell me no no or + + align:start position:0% +list as to who wants to tell me no no or + + + align:start position:0% +list as to who wants to tell me no no or +you look like you're ducking your head + + align:start position:0% +you look like you're ducking your head + + + align:start position:0% +you look like you're ducking your head +what's your name Wendy what did you take + + align:start position:0% +what's your name Wendy what did you take + + + align:start position:0% +what's your name Wendy what did you take +from the seven pages of the Geneva + + align:start position:0% +from the seven pages of the Geneva + + + align:start position:0% +from the seven pages of the Geneva +report + + align:start position:0% + + + + align:start position:0% + +did you read did you do the readings + + align:start position:0% +did you read did you do the readings + + + align:start position:0% +did you read did you do the readings +lady take from the great work of Simon + + align:start position:0% +lady take from the great work of Simon + + + align:start position:0% +lady take from the great work of Simon +Johnson and I helped him out you know + + align:start position:0% + + + + align:start position:0% + +anything about the business challenges + + align:start position:0% +anything about the business challenges + + + align:start position:0% +anything about the business challenges +of blockchain from the readings so one + + align:start position:0% +of blockchain from the readings so one + + + align:start position:0% +of blockchain from the readings so one +one challenge is time latency it takes a + + align:start position:0% +one challenge is time latency it takes a + + + align:start position:0% +one challenge is time latency it takes a +long time to do a Wendy raise raises yes + + align:start position:0% +long time to do a Wendy raise raises yes + + + align:start position:0% +long time to do a Wendy raise raises yes +if you can say your first name help + + align:start position:0% +if you can say your first name help + + + align:start position:0% +if you can say your first name help +Sabrina out get you off the list + + align:start position:0% +Sabrina out get you off the list + + + align:start position:0% +Sabrina out get you off the list +so you it's self-motivation to say your + + align:start position:0% +so you it's self-motivation to say your + + + align:start position:0% +so you it's self-motivation to say your +name so catalina sort of related they're + + align:start position:0% +name so catalina sort of related they're + + + align:start position:0% +name so catalina sort of related they're +there they're not alone but performance + + align:start position:0% +there they're not alone but performance + + + align:start position:0% +there they're not alone but performance +scalability the time it takes to do a + + align:start position:0% +scalability the time it takes to do a + + + align:start position:0% +scalability the time it takes to do a +transaction other challenges yes how to + + align:start position:0% +transaction other challenges yes how to + + + align:start position:0% +transaction other challenges yes how to +do micro payments you want to tease that + + align:start position:0% +do micro payments you want to tease that + + + align:start position:0% +do micro payments you want to tease that +out why why is there a problem with + + align:start position:0% +out why why is there a problem with + + + align:start position:0% +out why why is there a problem with +micro payments do micro payments in the + + align:start position:0% +micro payments do micro payments in the + + + align:start position:0% +micro payments do micro payments in the +small micro payments partly because + + align:start position:0% +small micro payments partly because + + + align:start position:0% +small micro payments partly because +they're so small maybe relative to the + + align:start position:0% +they're so small maybe relative to the + + + align:start position:0% +they're so small maybe relative to the +fees and the cost of the network Alexis + + align:start position:0% + + + + align:start position:0% + +may try to change the transaction + + align:start position:0% + + + + align:start position:0% + +there's economic incentives that are + + align:start position:0% +there's economic incentives that are + + + align:start position:0% +there's economic incentives that are +involved here we're now moving a little + + align:start position:0% +involved here we're now moving a little + + + align:start position:0% +involved here we're now moving a little +bit away from all that you know that + + align:start position:0% +bit away from all that you know that + + + align:start position:0% +bit away from all that you know that +stuff the the broccoli that I said that + + align:start position:0% +stuff the the broccoli that I said that + + + align:start position:0% +stuff the the broccoli that I said that +we were all going to be eating about + + align:start position:0% +we were all going to be eating about + + + align:start position:0% +we were all going to be eating about +hash functions and so forth + + align:start position:0% +hash functions and so forth + + + align:start position:0% +hash functions and so forth +akira yeah privacy regulators concerns + + align:start position:0% + + + + align:start position:0% + +here just raise a bunch of points about + + align:start position:0% +here just raise a bunch of points about + + + align:start position:0% +here just raise a bunch of points about +privacy and security about the + + align:start position:0% +privacy and security about the + + + align:start position:0% +privacy and security about the +individuals and the regulators is + + align:start position:0% +individuals and the regulators is + + + align:start position:0% +individuals and the regulators is +anybody want to tease that out a little + + align:start position:0% +anybody want to tease that out a little + + + align:start position:0% +anybody want to tease that out a little +bit more incentive to keep that natural + + align:start position:0% +bit more incentive to keep that natural + + + align:start position:0% +bit more incentive to keep that natural +public policy tension that doesn't only + + align:start position:0% +public policy tension that doesn't only + + + align:start position:0% +public policy tension that doesn't only +exist around one side there's a + + align:start position:0% +exist around one side there's a + + + align:start position:0% +exist around one side there's a +commercial interest to keep and + + align:start position:0% +commercial interest to keep and + + + align:start position:0% +commercial interest to keep and +interestingly on top of it the official + + align:start position:0% +interestingly on top of it the official + + + align:start position:0% +interestingly on top of it the official +sector also wants privacy for everybody + + align:start position:0% +sector also wants privacy for everybody + + + align:start position:0% +sector also wants privacy for everybody +other than the official sector so like + + align:start position:0% +other than the official sector so like + + + align:start position:0% +other than the official sector so like +in Europe there's a new requirement that + + align:start position:0% +in Europe there's a new requirement that + + + align:start position:0% +in Europe there's a new requirement that +wasn't in the breeze don't worry but is + + align:start position:0% +wasn't in the breeze don't worry but is + + + align:start position:0% +wasn't in the breeze don't worry but is +anybody familiar with the directive the + + align:start position:0% +anybody familiar with the directive the + + + align:start position:0% +anybody familiar with the directive the +privacy directive called GDP or Aaron + + align:start position:0% +privacy directive called GDP or Aaron + + + align:start position:0% +privacy directive called GDP or Aaron +Aaron doesn't tell the class a little + + align:start position:0% +Aaron doesn't tell the class a little + + + align:start position:0% +Aaron doesn't tell the class a little +bit about GDP or or if you there I just + + align:start position:0% +bit about GDP or or if you there I just + + + align:start position:0% +bit about GDP or or if you there I just +know that it's like a big deal right now + + align:start position:0% + + + + align:start position:0% + +especially when it comes like + + align:start position:0% +especially when it comes like + + + align:start position:0% +especially when it comes like +advertising to consumers they have + + align:start position:0% +advertising to consumers they have + + + align:start position:0% +advertising to consumers they have +consumers in like the EU have to like + + align:start position:0% +consumers in like the EU have to like + + + align:start position:0% +consumers in like the EU have to like +really like type certain boxes to + + align:start position:0% +really like type certain boxes to + + + align:start position:0% +really like type certain boxes to +we need to be advertised to as apposed + + align:start position:0% + + + + align:start position:0% + +and Joe Quinn you have the right to out + + align:start position:0% +and Joe Quinn you have the right to out + + + align:start position:0% +and Joe Quinn you have the right to out +of being everything you do work on + + align:start position:0% +of being everything you do work on + + + align:start position:0% +of being everything you do work on +summer we had to put purging mechanisms + + align:start position:0% +summer we had to put purging mechanisms + + + align:start position:0% +summer we had to put purging mechanisms +into our database right so it's a + + align:start position:0% +into our database right so it's a + + + align:start position:0% +into our database right so it's a +remarkable new law Europe is in a sense + + align:start position:0% +remarkable new law Europe is in a sense + + + align:start position:0% +remarkable new law Europe is in a sense +if you wish to say either more privacy + + align:start position:0% +if you wish to say either more privacy + + + align:start position:0% +if you wish to say either more privacy +protection or ahead of the u.s. or you + + align:start position:0% +protection or ahead of the u.s. or you + + + align:start position:0% +protection or ahead of the u.s. or you +know and each jurisdiction has their own + + align:start position:0% +know and each jurisdiction has their own + + + align:start position:0% +know and each jurisdiction has their own +cultural and political norms but Europe + + align:start position:0% +cultural and political norms but Europe + + + align:start position:0% +cultural and political norms but Europe +as a whole is moved further in a sense + + align:start position:0% +as a whole is moved further in a sense + + + align:start position:0% +as a whole is moved further in a sense +you have a right to be forgotten you + + align:start position:0% +you have a right to be forgotten you + + + align:start position:0% +you have a right to be forgotten you +have a right to access the information + + align:start position:0% +have a right to access the information + + + align:start position:0% +have a right to access the information +as well and so how to be forgotten in + + align:start position:0% +as well and so how to be forgotten in + + + align:start position:0% +as well and so how to be forgotten in +the context of an immutable blockchain + + align:start position:0% +the context of an immutable blockchain + + + align:start position:0% +the context of an immutable blockchain +isn't interesting just technical set of + + align:start position:0% +isn't interesting just technical set of + + + align:start position:0% +isn't interesting just technical set of +issues yes I work for a company this + + align:start position:0% +issues yes I work for a company this + + + align:start position:0% +issues yes I work for a company this +summer the processes transactions and it + + align:start position:0% +summer the processes transactions and it + + + align:start position:0% +summer the processes transactions and it +was our understanding speaking with + + align:start position:0% +was our understanding speaking with + + + align:start position:0% +was our understanding speaking with +lawyers in Europe that under gdpr you're + + align:start position:0% +lawyers in Europe that under gdpr you're + + + align:start position:0% +lawyers in Europe that under gdpr you're +allowed to request your transactions + + align:start position:0% +allowed to request your transactions + + + align:start position:0% +allowed to request your transactions +because the transactions counters + + align:start position:0% +because the transactions counters + + + align:start position:0% +because the transactions counters +personal information you're allowed to + + align:start position:0% +personal information you're allowed to + + + align:start position:0% +personal information you're allowed to +request your transactions to be erased + + align:start position:0% +request your transactions to be erased + + + align:start position:0% +request your transactions to be erased +from the ledger which obviously opens + + align:start position:0% +from the ledger which obviously opens + + + align:start position:0% +from the ledger which obviously opens +the door to all kinds of fraudulent + + align:start position:0% +the door to all kinds of fraudulent + + + align:start position:0% +the door to all kinds of fraudulent +behavior I'm just curious to know you've + + align:start position:0% +behavior I'm just curious to know you've + + + align:start position:0% +behavior I'm just curious to know you've +heard of any sort of resolution to that + + align:start position:0% +heard of any sort of resolution to that + + + align:start position:0% +heard of any sort of resolution to that +I haven't I was speaking at a conference + + align:start position:0% +I haven't I was speaking at a conference + + + align:start position:0% +I haven't I was speaking at a conference +earlier today here at MIT with a bunch + + align:start position:0% +earlier today here at MIT with a bunch + + + align:start position:0% +earlier today here at MIT with a bunch +of member companies to the computer + + align:start position:0% +of member companies to the computer + + + align:start position:0% +of member companies to the computer +science and AI lab and one of the + + align:start position:0% +science and AI lab and one of the + + + align:start position:0% +science and AI lab and one of the +participants said they thought they had + + align:start position:0% +participants said they thought they had + + + align:start position:0% +participants said they thought they had +a technical set of solutions to it so + + align:start position:0% +a technical set of solutions to it so + + + align:start position:0% +a technical set of solutions to it so +we're gonna talk more about the privacy + + align:start position:0% +we're gonna talk more about the privacy + + + align:start position:0% +we're gonna talk more about the privacy +issues and GDP or in the public policy + + align:start position:0% +issues and GDP or in the public policy + + + align:start position:0% +issues and GDP or in the public policy +session next week so I'll try to I'll + + align:start position:0% +session next week so I'll try to I'll + + + align:start position:0% +session next week so I'll try to I'll +try to Kyle remind me and I will try to + + align:start position:0% +try to Kyle remind me and I will try to + + + align:start position:0% +try to Kyle remind me and I will try to +get more up to speed on that Kelly + + align:start position:0% +get more up to speed on that Kelly + + + align:start position:0% +get more up to speed on that Kelly +it's specifically for chapter there was + + align:start position:0% +it's specifically for chapter there was + + + align:start position:0% +it's specifically for chapter there was +something mentioned about what makes + + align:start position:0% +something mentioned about what makes + + + align:start position:0% +something mentioned about what makes +watching uniquely qualified to solve a + + align:start position:0% +watching uniquely qualified to solve a + + + align:start position:0% +watching uniquely qualified to solve a +lot of these solutions and I found the + + align:start position:0% +lot of these solutions and I found the + + + align:start position:0% +lot of these solutions and I found the +date had coincided with what special + + align:start position:0% +date had coincided with what special + + + align:start position:0% +date had coincided with what special +Essex said last class about there are + + align:start position:0% +Essex said last class about there are + + + align:start position:0% +Essex said last class about there are +significant trade-offs that often come + + align:start position:0% +significant trade-offs that often come + + + align:start position:0% +significant trade-offs that often come +down to the cost of trust but it's so + + align:start position:0% +down to the cost of trust but it's so + + + align:start position:0% +down to the cost of trust but it's so +thanks affection with so many technical + + align:start position:0% +thanks affection with so many technical + + + align:start position:0% +thanks affection with so many technical +challenges why other thoughts or + + align:start position:0% +challenges why other thoughts or + + + align:start position:0% +challenges why other thoughts or +questions from the readings it's okay + + align:start position:0% +questions from the readings it's okay + + + align:start position:0% +questions from the readings it's okay +about having a second layer to provide + + align:start position:0% +about having a second layer to provide + + + align:start position:0% +about having a second layer to provide +the efficiency and the high performance + + align:start position:0% +the efficiency and the high performance + + + align:start position:0% +the efficiency and the high performance +but it's ready offline yeah so we are + + align:start position:0% +but it's ready offline yeah so we are + + + align:start position:0% +but it's ready offline yeah so we are +expecting to trust in second base + + align:start position:0% +expecting to trust in second base + + + align:start position:0% +expecting to trust in second base +offline and then goes and put inside the + + align:start position:0% +offline and then goes and put inside the + + + align:start position:0% +offline and then goes and put inside the +box chain how feasible how can we twist + + align:start position:0% +box chain how feasible how can we twist + + + align:start position:0% +box chain how feasible how can we twist +the question is about possible solutions + + align:start position:0% +the question is about possible solutions + + + align:start position:0% +the question is about possible solutions +to address performance and scalability + + align:start position:0% +to address performance and scalability + + + align:start position:0% +to address performance and scalability +and I have a few slides on that but in + + align:start position:0% +and I have a few slides on that but in + + + align:start position:0% +and I have a few slides on that but in +essence if the if the principal protocol + + align:start position:0% +essence if the if the principal protocol + + + align:start position:0% +essence if the if the principal protocol +the Bitcoin protocol or the etherium + + align:start position:0% +the Bitcoin protocol or the etherium + + + align:start position:0% +the Bitcoin protocol or the etherium +protocol or maybe tomorrow be EOS or + + align:start position:0% +protocol or maybe tomorrow be EOS or + + + align:start position:0% +protocol or maybe tomorrow be EOS or +some other protocol has some performance + + align:start position:0% +some other protocol has some performance + + + align:start position:0% +some other protocol has some performance +issues could some activity be moved to + + align:start position:0% +issues could some activity be moved to + + + align:start position:0% +issues could some activity be moved to +another channel that channel could be + + align:start position:0% +another channel that channel could be + + + align:start position:0% +another channel that channel could be +caught a layer two and the Lightning + + align:start position:0% +caught a layer two and the Lightning + + + align:start position:0% +caught a layer two and the Lightning +Network which was there was a reading + + align:start position:0% +Network which was there was a reading + + + align:start position:0% +Network which was there was a reading +about that that could be with a little + + align:start position:0% +about that that could be with a little + + + align:start position:0% +about that that could be with a little +bit different technology called side + + align:start position:0% +bit different technology called side + + + align:start position:0% +bit different technology called side +chains or shorting which I think was an + + align:start position:0% +chains or shorting which I think was an + + + align:start position:0% +chains or shorting which I think was an +optional yeah I did that optionally I + + align:start position:0% +optional yeah I did that optionally I + + + align:start position:0% +optional yeah I did that optionally I +didn't force you all so there's a number + + align:start position:0% +didn't force you all so there's a number + + + align:start position:0% +didn't force you all so there's a number +of alternative channels and though the + + align:start position:0% +of alternative channels and though the + + + align:start position:0% +of alternative channels and though the +technologies are - technologists + + align:start position:0% +technologies are - technologists + + + align:start position:0% +technologies are - technologists +importantly different sharding and side + + align:start position:0% +importantly different sharding and side + + + align:start position:0% +importantly different sharding and side +chains and layer two for this purpose + + align:start position:0% +chains and layer two for this purpose + + + align:start position:0% +chains and layer two for this purpose +for a moment let me + + align:start position:0% +for a moment let me + + + align:start position:0% +for a moment let me +blur over the differences the question + + align:start position:0% +blur over the differences the question + + + align:start position:0% +blur over the differences the question +that Lea Lea our dros ask is well is + + align:start position:0% +that Lea Lea our dros ask is well is + + + align:start position:0% +that Lea Lea our dros ask is well is +that meaning that we have to trust I + + align:start position:0% +that meaning that we have to trust I + + + align:start position:0% +that meaning that we have to trust I +would contend we already have to trust + + align:start position:0% +would contend we already have to trust + + + align:start position:0% +would contend we already have to trust +the protocol that the Bitcoin core + + align:start position:0% +the protocol that the Bitcoin core + + + align:start position:0% +the protocol that the Bitcoin core +developers have written it's open github + + align:start position:0% +developers have written it's open github + + + align:start position:0% +developers have written it's open github +it's open code but very few people are + + align:start position:0% +it's open code but very few people are + + + align:start position:0% +it's open code but very few people are +actually gonna investigate it enough to + + align:start position:0% +actually gonna investigate it enough to + + + align:start position:0% +actually gonna investigate it enough to +be assured there's not a bug or an error + + align:start position:0% +be assured there's not a bug or an error + + + align:start position:0% +be assured there's not a bug or an error +but I agree with you that the the core + + align:start position:0% +but I agree with you that the the core + + + align:start position:0% +but I agree with you that the the core +the Bitcoin core or the etherium core + + align:start position:0% +the Bitcoin core or the etherium core + + + align:start position:0% +the Bitcoin core or the etherium core +has been living in if I could call it + + align:start position:0% +has been living in if I could call it + + + align:start position:0% +has been living in if I could call it +the technological and commercial swamp + + align:start position:0% +the technological and commercial swamp + + + align:start position:0% +the technological and commercial swamp +it's been attacked by so many viruses + + align:start position:0% +it's been attacked by so many viruses + + + align:start position:0% +it's been attacked by so many viruses +and bugs you have some reason to trust + + align:start position:0% +and bugs you have some reason to trust + + + align:start position:0% +and bugs you have some reason to trust +it but you should never be a hundred + + align:start position:0% +it but you should never be a hundred + + + align:start position:0% +it but you should never be a hundred +percent sure the side the side chains + + align:start position:0% +percent sure the side the side chains + + + align:start position:0% +percent sure the side the side chains +are less tested but I do agree with you + + align:start position:0% +are less tested but I do agree with you + + + align:start position:0% +are less tested but I do agree with you +you have some trust and unless I + + align:start position:0% +you have some trust and unless I + + + align:start position:0% +you have some trust and unless I +misunderstand the question I thought it + + align:start position:0% +misunderstand the question I thought it + + + align:start position:0% +misunderstand the question I thought it +was a trust in the in the underlying + + align:start position:0% +was a trust in the in the underlying + + + align:start position:0% +was a trust in the in the underlying +code working with me that's if you're + + align:start position:0% +code working with me that's if you're + + + align:start position:0% +code working with me that's if you're +off chain should you be more worried I + + align:start position:0% +off chain should you be more worried I + + + align:start position:0% +off chain should you be more worried I +was addressing just a narrow part about + + align:start position:0% +was addressing just a narrow part about + + + align:start position:0% +was addressing just a narrow part about +the code you're saying should you be + + align:start position:0% +the code you're saying should you be + + + align:start position:0% +the code you're saying should you be +worried because it doesn't have the same + + align:start position:0% +worried because it doesn't have the same + + + align:start position:0% +worried because it doesn't have the same +validation models so can I hold that + + align:start position:0% +validation models so can I hold that + + + align:start position:0% +validation models so can I hold that +question until we get to the slides + + align:start position:0% +question until we get to the slides + + + align:start position:0% +question until we get to the slides +because I think that I think you do + + align:start position:0% +because I think that I think you do + + + align:start position:0% +because I think that I think you do +actually have some pretty good + + align:start position:0% +actually have some pretty good + + + align:start position:0% +actually have some pretty good +validation but I think you're right that + + align:start position:0% +validation but I think you're right that + + + align:start position:0% +validation but I think you're right that +it's a it's a valid question is the + + align:start position:0% +it's a it's a valid question is the + + + align:start position:0% +it's a it's a valid question is the +validation and these off chains still + + align:start position:0% +validation and these off chains still + + + align:start position:0% +validation and these off chains still +work there was a question back here I + + align:start position:0% +work there was a question back here I + + + align:start position:0% +work there was a question back here I +was just sort of gonna respond to the + + align:start position:0% +was just sort of gonna respond to the + + + align:start position:0% +was just sort of gonna respond to the +issue like sort of trusting these + + align:start position:0% +issue like sort of trusting these + + + align:start position:0% +issue like sort of trusting these +offline mechanisms it's not in the same + + align:start position:0% +offline mechanisms it's not in the same + + + align:start position:0% +offline mechanisms it's not in the same +thing but like 90% of according to this + + align:start position:0% +thing but like 90% of according to this + + + align:start position:0% +thing but like 90% of according to this +of like daily trading volume occurs in + + align:start position:0% +of like daily trading volume occurs in + + + align:start position:0% +of like daily trading volume occurs in +these crypto exchanges so that's also + + align:start position:0% +these crypto exchanges so that's also + + + align:start position:0% +these crypto exchanges so that's also +like sort of happening off the chain so + + align:start position:0% +like sort of happening off the chain so + + + align:start position:0% +like sort of happening off the chain so +I think that like in this community of + + align:start position:0% +I think that like in this community of + + + align:start position:0% +I think that like in this community of +people who are like currently + + align:start position:0% +people who are like currently + + + align:start position:0% +people who are like currently +participating there's no reason that + + align:start position:0% +participating there's no reason that + + + align:start position:0% +participating there's no reason that +like we're not going to + + align:start position:0% + + + + align:start position:0% + +so you're raising the point and it's a + + align:start position:0% +so you're raising the point and it's a + + + align:start position:0% +so you're raising the point and it's a +sort of an irony of the whole ecosystem + + align:start position:0% +sort of an irony of the whole ecosystem + + + align:start position:0% +sort of an irony of the whole ecosystem +that the majority and in some crypto + + align:start position:0% +that the majority and in some crypto + + + align:start position:0% +that the majority and in some crypto +currencies over 90% of the actual daily + + align:start position:0% +currencies over 90% of the actual daily + + + align:start position:0% +currencies over 90% of the actual daily +transactions are happening in in very + + align:start position:0% +transactions are happening in in very + + + align:start position:0% +transactions are happening in in very +centralized ways on exchanges + + align:start position:0% +centralized ways on exchanges + + + align:start position:0% +centralized ways on exchanges +particularly the centralized crypto + + align:start position:0% +particularly the centralized crypto + + + align:start position:0% +particularly the centralized crypto +exchanges where I can't remember what it + + align:start position:0% +exchanges where I can't remember what it + + + align:start position:0% +exchanges where I can't remember what it +was about half of you have owned Bitcoin + + align:start position:0% +was about half of you have owned Bitcoin + + + align:start position:0% +was about half of you have owned Bitcoin +at some point in time but can I ask how + + align:start position:0% +at some point in time but can I ask how + + + align:start position:0% +at some point in time but can I ask how +many of you have actually operated a + + align:start position:0% +many of you have actually operated a + + + align:start position:0% +many of you have actually operated a +full node so there's the two + + align:start position:0% +full node so there's the two + + + align:start position:0% +full node so there's the two +technologists at the middle table and + + align:start position:0% +technologists at the middle table and + + + align:start position:0% +technologists at the middle table and +Hugo who's also if I remember + + align:start position:0% +Hugo who's also if I remember + + + align:start position:0% +Hugo who's also if I remember +engineering PhD student okay + + align:start position:0% +engineering PhD student okay + + + align:start position:0% +engineering PhD student okay +so we have our three PhD students who + + align:start position:0% +so we have our three PhD students who + + + align:start position:0% +so we have our three PhD students who +have operated full notes honors to you + + align:start position:0% +have operated full notes honors to you + + + align:start position:0% +have operated full notes honors to you +but for most of you and it was half the + + align:start position:0% +but for most of you and it was half the + + + align:start position:0% +but for most of you and it was half the +class of own some Bitcoin you've trusted + + align:start position:0% +class of own some Bitcoin you've trusted + + + align:start position:0% +class of own some Bitcoin you've trusted +some other authority to hold your + + align:start position:0% +some other authority to hold your + + + align:start position:0% +some other authority to hold your +private keys I'm not saying you're wrong + + align:start position:0% +private keys I'm not saying you're wrong + + + align:start position:0% +private keys I'm not saying you're wrong +or right but it's an interesting and an + + align:start position:0% +or right but it's an interesting and an + + + align:start position:0% +or right but it's an interesting and an +important point about this ecosystem so + + align:start position:0% +important point about this ecosystem so + + + align:start position:0% +important point about this ecosystem so +let me let me unless there's other + + align:start position:0% +let me let me unless there's other + + + align:start position:0% +let me let me unless there's other +points just go through some of how I + + align:start position:0% +points just go through some of how I + + + align:start position:0% +points just go through some of how I +thought about these things and laid it + + align:start position:0% +thought about these things and laid it + + + align:start position:0% +thought about these things and laid it +out and I I of course the study + + align:start position:0% +out and I I of course the study + + + align:start position:0% +out and I I of course the study +questions we've been talking about so + + align:start position:0% +questions we've been talking about so + + + align:start position:0% +questions we've been talking about so +I'll come come back but we will talk a + + align:start position:0% +I'll come come back but we will talk a + + + align:start position:0% +I'll come come back but we will talk a +little bit about hard forks and and we + + align:start position:0% +little bit about hard forks and and we + + + align:start position:0% +little bit about hard forks and and we +we I didn't hear anybody talk about + + align:start position:0% +we I didn't hear anybody talk about + + + align:start position:0% +we I didn't hear anybody talk about +interoperability so we'll come back to + + align:start position:0% +interoperability so we'll come back to + + + align:start position:0% +interoperability so we'll come back to +that as well we've talked more about + + align:start position:0% +that as well we've talked more about + + + align:start position:0% +that as well we've talked more about +performance and privacy issues just back + + align:start position:0% +performance and privacy issues just back + + + align:start position:0% +performance and privacy issues just back +to the technical features it's just + + align:start position:0% +to the technical features it's just + + + align:start position:0% +to the technical features it's just +repetition sorry but I do think it's + + align:start position:0% +repetition sorry but I do think it's + + + align:start position:0% +repetition sorry but I do think it's +worthwhile there's of course the + + align:start position:0% +worthwhile there's of course the + + + align:start position:0% +worthwhile there's of course the +cryptography and timestamp logs so the + + align:start position:0% +cryptography and timestamp logs so the + + + align:start position:0% +cryptography and timestamp logs so the +the bedrock of of this technology that + + align:start position:0% +the bedrock of of this technology that + + + align:start position:0% +the bedrock of of this technology that +we did three or four lectures ago you + + align:start position:0% +we did three or four lectures ago you + + + align:start position:0% +we did three or four lectures ago you +will find that in permission systems + + align:start position:0% +will find that in permission systems + + + align:start position:0% +will find that in permission systems +you'll find it in permissionless systems + + align:start position:0% +you'll find it in permissionless systems + + + align:start position:0% +you'll find it in permissionless systems +that is a bedrock you will find it in a + + align:start position:0% +that is a bedrock you will find it in a + + + align:start position:0% +that is a bedrock you will find it in a +theory of Bitcoin and sixteen hundred + + align:start position:0% +theory of Bitcoin and sixteen hundred + + + align:start position:0% +theory of Bitcoin and sixteen hundred +others there there will be some shifts + + align:start position:0% +others there there will be some shifts + + + align:start position:0% +others there there will be some shifts +around the hash functions might be a + + align:start position:0% +around the hash functions might be a + + + align:start position:0% +around the hash functions might be a +little different but that's kind of a + + align:start position:0% +little different but that's kind of a + + + align:start position:0% +little different but that's kind of a +bedrock + + align:start position:0% +bedrock + + + align:start position:0% +bedrock +of this technology the network consensus + + align:start position:0% +of this technology the network consensus + + + align:start position:0% +of this technology the network consensus +is not necessarily always the same as we + + align:start position:0% +is not necessarily always the same as we + + + align:start position:0% +is not necessarily always the same as we +talked about sometimes it's proof of + + align:start position:0% +talked about sometimes it's proof of + + + align:start position:0% +talked about sometimes it's proof of +work sometimes it's proof of stake or in + + align:start position:0% +work sometimes it's proof of stake or in + + + align:start position:0% +work sometimes it's proof of stake or in +the permission systems the consensus is + + align:start position:0% +the permission systems the consensus is + + + align:start position:0% +the permission systems the consensus is +really are you amongst the club and then + + align:start position:0% +really are you amongst the club and then + + + align:start position:0% +really are you amongst the club and then +there's kind of some form of a club deal + + align:start position:0% +there's kind of some form of a club deal + + + align:start position:0% +there's kind of some form of a club deal +if you're the Australian Stock Exchange + + align:start position:0% +if you're the Australian Stock Exchange + + + align:start position:0% +if you're the Australian Stock Exchange +the only member of the club is the + + align:start position:0% +the only member of the club is the + + + align:start position:0% +the only member of the club is the +Australian Stock Exchange but in other + + align:start position:0% +Australian Stock Exchange but in other + + + align:start position:0% +Australian Stock Exchange but in other +permission systems it's 20 banks or 15 + + align:start position:0% +permission systems it's 20 banks or 15 + + + align:start position:0% +permission systems it's 20 banks or 15 +banks that are sharing that some + + align:start position:0% +banks that are sharing that some + + + align:start position:0% +banks that are sharing that some +delegated randomized Authority to say + + align:start position:0% +delegated randomized Authority to say + + + align:start position:0% +delegated randomized Authority to say +what's the next amendment to thee and + + align:start position:0% +what's the next amendment to thee and + + + align:start position:0% +what's the next amendment to thee and +then the transactions code and Ledger's + + align:start position:0% + + + + align:start position:0% + +shifts largely dependent upon whether + + align:start position:0% +shifts largely dependent upon whether + + + align:start position:0% +shifts largely dependent upon whether +it's a transaction ledger or an account + + align:start position:0% +it's a transaction ledger or an account + + + align:start position:0% +it's a transaction ledger or an account +ledger so transaction Ledger's have to + + align:start position:0% +ledger so transaction Ledger's have to + + + align:start position:0% +ledger so transaction Ledger's have to +have some way to record transactions + + align:start position:0% +have some way to record transactions + + + align:start position:0% +have some way to record transactions +account ledgers have to have some way to + + align:start position:0% +account ledgers have to have some way to + + + align:start position:0% +account ledgers have to have some way to +record the change in accounts which eat + + align:start position:0% +record the change in accounts which eat + + + align:start position:0% +record the change in accounts which eat +their cause state transitions but either + + align:start position:0% +their cause state transitions but either + + + align:start position:0% +their cause state transitions but either +you have to record a transaction or you + + align:start position:0% +you have to record a transaction or you + + + align:start position:0% +you have to record a transaction or you +have to record a change in the state or + + align:start position:0% +have to record a change in the state or + + + align:start position:0% +have to record a change in the state or +a change in the account an account would + + align:start position:0% +a change in the account an account would + + + align:start position:0% +a change in the account an account would +say that would be like the income + + align:start position:0% +say that would be like the income + + + align:start position:0% +say that would be like the income +statement versus the balance sheet but + + align:start position:0% +statement versus the balance sheet but + + + align:start position:0% +statement versus the balance sheet but +you kind of need to record that and + + align:start position:0% +you kind of need to record that and + + + align:start position:0% +you kind of need to record that and +basically all of these technologies as I + + align:start position:0% +basically all of these technologies as I + + + align:start position:0% +basically all of these technologies as I +understand it have some way to keep + + align:start position:0% +understand it have some way to keep + + + align:start position:0% +understand it have some way to keep +those Ledger's though there's multiple + + align:start position:0% +those Ledger's though there's multiple + + + align:start position:0% +those Ledger's though there's multiple +ways to do it and as we talked about + + align:start position:0% +ways to do it and as we talked about + + + align:start position:0% +ways to do it and as we talked about +last week some have one Merkle tree and + + align:start position:0% +last week some have one Merkle tree and + + + align:start position:0% +last week some have one Merkle tree and +some have four or five Merkle trees and + + align:start position:0% +some have four or five Merkle trees and + + + align:start position:0% +some have four or five Merkle trees and +so forth but it's it's embedded in this + + align:start position:0% +so forth but it's it's embedded in this + + + align:start position:0% +so forth but it's it's embedded in this +and they could have different scripting + + align:start position:0% +and they could have different scripting + + + align:start position:0% +and they could have different scripting +questions just that's like the thumbnail + + align:start position:0% +questions just that's like the thumbnail + + + align:start position:0% +questions just that's like the thumbnail +just to remind you about the technology + + align:start position:0% +just to remind you about the technology + + + align:start position:0% +just to remind you about the technology +it's the T and MIT so for a transaction + + align:start position:0% +it's the T and MIT so for a transaction + + + align:start position:0% +it's the T and MIT so for a transaction +versus account in an account based + + align:start position:0% +versus account in an account based + + + align:start position:0% +versus account in an account based +ledger does it say like if you spend + + align:start position:0% +ledger does it say like if you spend + + + align:start position:0% +ledger does it say like if you spend +five dollars to say who you're spending + + align:start position:0% +five dollars to say who you're spending + + + align:start position:0% +five dollars to say who you're spending +that five dollars to just say your + + align:start position:0% +that five dollars to just say your + + + align:start position:0% +that five dollars to just say your +account went down five dollars and + + align:start position:0% +account went down five dollars and + + + align:start position:0% +account went down five dollars and +somebody else went out five dollars it + + align:start position:0% +somebody else went out five dollars it + + + align:start position:0% +somebody else went out five dollars it +doesn't matter + + align:start position:0% +doesn't matter + + + align:start position:0% +doesn't matter +so I'm gonna take as I understand ether + + align:start position:0% +so I'm gonna take as I understand ether + + + align:start position:0% +so I'm gonna take as I understand ether +and medoras you'll bail me out but you + + align:start position:0% +and medoras you'll bail me out but you + + + align:start position:0% +and medoras you'll bail me out but you +you put a state-transition instead of a + + align:start position:0% +you put a state-transition instead of a + + + align:start position:0% +you put a state-transition instead of a +transaction input it's a + + align:start position:0% +transaction input it's a + + + align:start position:0% +transaction input it's a +state-transition input and that state + + align:start position:0% +state-transition input and that state + + + align:start position:0% +state-transition input and that state +transition input does have one account + + align:start position:0% +transition input does have one account + + + align:start position:0% +transition input does have one account +going down another count going up you + + align:start position:0% +going down another count going up you + + + align:start position:0% +going down another count going up you +can see both sides of it as I understand + + align:start position:0% +can see both sides of it as I understand + + + align:start position:0% +can see both sides of it as I understand +and there's a receipt ledger there's + + align:start position:0% +and there's a receipt ledger there's + + + align:start position:0% +and there's a receipt ledger there's +actually a receipt Merkle tree that then + + align:start position:0% +actually a receipt Merkle tree that then + + + align:start position:0% +actually a receipt Merkle tree that then +keeps this state transition happened did + + align:start position:0% +keeps this state transition happened did + + + align:start position:0% +keeps this state transition happened did +I did I roughly get that right Medora + + align:start position:0% +I did I roughly get that right Medora + + + align:start position:0% +I did I roughly get that right Medora +Wow all right medoras actually does this + + align:start position:0% +Wow all right medoras actually does this + + + align:start position:0% +Wow all right medoras actually does this +for a living I mean he's he's the one of + + align:start position:0% +for a living I mean he's he's the one of + + + align:start position:0% +for a living I mean he's he's the one of +the founding people of Z cash so and a + + align:start position:0% +the founding people of Z cash so and a + + + align:start position:0% +the founding people of Z cash so and a +bunch of other wonderful things I'm not + + align:start position:0% +bunch of other wonderful things I'm not + + + align:start position:0% +bunch of other wonderful things I'm not +going to go through each of the details + + align:start position:0% +going to go through each of the details + + + align:start position:0% +going to go through each of the details +but there was about 15 or 20 details in + + align:start position:0% +but there was about 15 or 20 details in + + + align:start position:0% +but there was about 15 or 20 details in +these slides about the differences + + align:start position:0% +these slides about the differences + + + align:start position:0% +these slides about the differences +between Bitcoin and ether and I just use + + align:start position:0% +between Bitcoin and ether and I just use + + + align:start position:0% +between Bitcoin and ether and I just use +it to remind because it's saying okay + + align:start position:0% +it to remind because it's saying okay + + + align:start position:0% +it to remind because it's saying okay +why why why did the professor why did + + align:start position:0% +why why why did the professor why did + + + align:start position:0% +why why why did the professor why did +the why did Gary put it up there this + + align:start position:0% +the why did Gary put it up there this + + + align:start position:0% +the why did Gary put it up there this +professor lesyk that was nice for Larry + + align:start position:0% +professor lesyk that was nice for Larry + + + align:start position:0% +professor lesyk that was nice for Larry +but for me but in essence the big + + align:start position:0% +but for me but in essence the big + + + align:start position:0% +but for me but in essence the big +difference is account based versus + + align:start position:0% +difference is account based versus + + + align:start position:0% +difference is account based versus +transaction base the kind of big + + align:start position:0% +transaction base the kind of big + + + align:start position:0% +transaction base the kind of big +difference is ether does seem to go + + align:start position:0% +difference is ether does seem to go + + + align:start position:0% +difference is ether does seem to go +faster but it doesn't have a lot of + + align:start position:0% +faster but it doesn't have a lot of + + + align:start position:0% +faster but it doesn't have a lot of +throughput they still both use proof of + + align:start position:0% +throughput they still both use proof of + + + align:start position:0% +throughput they still both use proof of +work even though ether says they're + + align:start position:0% +work even though ether says they're + + + align:start position:0% +work even though ether says they're +going to move to proof of state they're + + align:start position:0% +going to move to proof of state they're + + + align:start position:0% +going to move to proof of state they're +not there yet when they get there we'll + + align:start position:0% +not there yet when they get there we'll + + + align:start position:0% +not there yet when they get there we'll +all know together the economics are a + + align:start position:0% +all know together the economics are a + + + align:start position:0% +all know together the economics are a +bit difference of course as well and but + + align:start position:0% +bit difference of course as well and but + + + align:start position:0% +bit difference of course as well and but +all of these details are part of the + + align:start position:0% +all of these details are part of the + + + align:start position:0% +all of these details are part of the +reason why there's problems and so you + + align:start position:0% +reason why there's problems and so you + + + align:start position:0% +reason why there's problems and so you +read in the Geneva report a little bit + + align:start position:0% +read in the Geneva report a little bit + + + align:start position:0% +read in the Geneva report a little bit +about a professor an economist from the + + align:start position:0% +about a professor an economist from the + + + align:start position:0% +about a professor an economist from the +1930s does anybody want to take a crack + + align:start position:0% +1930s does anybody want to take a crack + + + align:start position:0% +1930s does anybody want to take a crack +at it or should I just do my slides here + + align:start position:0% +at it or should I just do my slides here + + + align:start position:0% +at it or should I just do my slides here +we go + + align:start position:0% + + + + align:start position:0% + +like cost-benefit analysis so that like + + align:start position:0% +like cost-benefit analysis so that like + + + align:start position:0% +like cost-benefit analysis so that like +if one wants to use tool of changes in + + align:start position:0% +if one wants to use tool of changes in + + + align:start position:0% +if one wants to use tool of changes in +tries Network you should take into + + align:start position:0% +tries Network you should take into + + + align:start position:0% +tries Network you should take into +account like all the benefits in terms + + align:start position:0% +account like all the benefits in terms + + + align:start position:0% +account like all the benefits in terms +of reducing cost of petrology enhancing + + align:start position:0% +of reducing cost of petrology enhancing + + + align:start position:0% +of reducing cost of petrology enhancing +security but also like the cost of like + + align:start position:0% +security but also like the cost of like + + + align:start position:0% +security but also like the cost of like +switching to it isn't release + + align:start position:0% +switching to it isn't release + + + align:start position:0% +switching to it isn't release +Koko's is a is an economist from the + + align:start position:0% +Koko's is a is an economist from the + + + align:start position:0% +Koko's is a is an economist from the +1930s who wrote extensively about the + + align:start position:0% +1930s who wrote extensively about the + + + align:start position:0% +1930s who wrote extensively about the +costs and appearing about the + + align:start position:0% +costs and appearing about the + + + align:start position:0% +costs and appearing about the +corporation kelly much earlier time way + + align:start position:0% +corporation kelly much earlier time way + + + align:start position:0% +corporation kelly much earlier time way +pre bitcoin but a different why does + + align:start position:0% +pre bitcoin but a different why does + + + align:start position:0% +pre bitcoin but a different why does +economic activity cluster into a firm + + align:start position:0% +economic activity cluster into a firm + + + align:start position:0% +economic activity cluster into a firm +rather than if it was truly market base + + align:start position:0% +rather than if it was truly market base + + + align:start position:0% +rather than if it was truly market base +i might just be selling my services in + + align:start position:0% +i might just be selling my services in + + + align:start position:0% +i might just be selling my services in +essence he was asking the question why + + align:start position:0% +essence he was asking the question why + + + align:start position:0% +essence he was asking the question why +don't we have a fully gig economy in the + + align:start position:0% +don't we have a fully gig economy in the + + + align:start position:0% +don't we have a fully gig economy in the +1930s where everybody's free labor and + + align:start position:0% +1930s where everybody's free labor and + + + align:start position:0% +1930s where everybody's free labor and +and and and even capital and labor meets + + align:start position:0% +and and and even capital and labor meets + + + align:start position:0% +and and and even capital and labor meets +individually and we collect up together + + align:start position:0% +individually and we collect up together + + + align:start position:0% +individually and we collect up together +that was kind of the body of his + + align:start position:0% +that was kind of the body of his + + + align:start position:0% +that was kind of the body of his +question that he was so centralization + + align:start position:0% +question that he was so centralization + + + align:start position:0% +question that he was so centralization +versus decentralization eighty years ago + + align:start position:0% +versus decentralization eighty years ago + + + align:start position:0% +versus decentralization eighty years ago +studied by a great economist so just + + align:start position:0% +studied by a great economist so just + + + align:start position:0% +studied by a great economist so just +thinking about it here a little bit + + align:start position:0% +thinking about it here a little bit + + + align:start position:0% +thinking about it here a little bit +i think that when you go from + + align:start position:0% +i think that when you go from + + + align:start position:0% +i think that when you go from +decentralization to centralization you + + align:start position:0% +decentralization to centralization you + + + align:start position:0% +decentralization to centralization you +tend on the centralized side you get + + align:start position:0% +tend on the centralized side you get + + + align:start position:0% +tend on the centralized side you get +capture you get economic rents and you + + align:start position:0% +capture you get economic rents and you + + + align:start position:0% +capture you get economic rents and you +do have a single point of failure in + + align:start position:0% +do have a single point of failure in + + + align:start position:0% +do have a single point of failure in +some sense the resiliency of the system + + align:start position:0% +some sense the resiliency of the system + + + align:start position:0% +some sense the resiliency of the system +whether it's in finance where you worry + + align:start position:0% +whether it's in finance where you worry + + + align:start position:0% +whether it's in finance where you worry +about systemic risk that one Clearing + + align:start position:0% +about systemic risk that one Clearing + + + align:start position:0% +about systemic risk that one Clearing +House one central bank one government if + + align:start position:0% +House one central bank one government if + + + align:start position:0% +House one central bank one government if +it's knocked out it's so relevant to the + + align:start position:0% +it's knocked out it's so relevant to the + + + align:start position:0% +it's knocked out it's so relevant to the +economy writ large it brings it down or + + align:start position:0% +economy writ large it brings it down or + + + align:start position:0% +economy writ large it brings it down or +if it's one database you have a single + + align:start position:0% +if it's one database you have a single + + + align:start position:0% +if it's one database you have a single +point in essence of failure economic + + align:start position:0% +point in essence of failure economic + + + align:start position:0% +point in essence of failure economic +rents is an ability to collect excess + + align:start position:0% +rents is an ability to collect excess + + + align:start position:0% +rents is an ability to collect excess +profits I assure you everybody in this + + align:start position:0% +profits I assure you everybody in this + + + align:start position:0% +profits I assure you everybody in this +class wants to collect economic + + align:start position:0% +class wants to collect economic + + + align:start position:0% +class wants to collect economic +rats we store it out as venture + + align:start position:0% +rats we store it out as venture + + + align:start position:0% +rats we store it out as venture +capitalists and entrepreneurs but we + + align:start position:0% +capitalists and entrepreneurs but we + + + align:start position:0% +capitalists and entrepreneurs but we +have a motivation and an incentive to be + + align:start position:0% +have a motivation and an incentive to be + + + align:start position:0% +have a motivation and an incentive to be +monopolist but we don't want to do it + + align:start position:0% +monopolist but we don't want to do it + + + align:start position:0% +monopolist but we don't want to do it +illegal of course I mean we just want to + + align:start position:0% +illegal of course I mean we just want to + + + align:start position:0% +illegal of course I mean we just want to +get there you know by dominating the + + align:start position:0% +get there you know by dominating the + + + align:start position:0% +get there you know by dominating the +market I'm sorry was there a question + + align:start position:0% +market I'm sorry was there a question + + + align:start position:0% +market I'm sorry was there a question +here you just read you're shaking your + + align:start position:0% +here you just read you're shaking your + + + align:start position:0% +here you just read you're shaking your +head and I didn't know but on the other + + align:start position:0% +head and I didn't know but on the other + + + align:start position:0% +head and I didn't know but on the other +side there's there's the benefits the + + align:start position:0% +side there's there's the benefits the + + + align:start position:0% +side there's there's the benefits the +the y scale is not written on here the Y + + align:start position:0% +the y scale is not written on here the Y + + + align:start position:0% +the y scale is not written on here the Y +scale is however you want to think of it + + align:start position:0% +scale is however you want to think of it + + + align:start position:0% +scale is however you want to think of it +but I think of it as kind of costs so + + align:start position:0% +but I think of it as kind of costs so + + + align:start position:0% +but I think of it as kind of costs so +the Y scale up the Y scale is like + + align:start position:0% +the Y scale up the Y scale is like + + + align:start position:0% +the Y scale up the Y scale is like +greater cost decentralization the big + + align:start position:0% +greater cost decentralization the big + + + align:start position:0% +greater cost decentralization the big +costs that come there is coordination + + align:start position:0% +costs that come there is coordination + + + align:start position:0% +costs that come there is coordination +you have a lot of collective action + + align:start position:0% +you have a lot of collective action + + + align:start position:0% +you have a lot of collective action +issues if the hundred or so people in + + align:start position:0% +issues if the hundred or so people in + + + align:start position:0% +issues if the hundred or so people in +this room we're trying to do something + + align:start position:0% +this room we're trying to do something + + + align:start position:0% +this room we're trying to do something +together you have to figure out how to + + align:start position:0% +together you have to figure out how to + + + align:start position:0% +together you have to figure out how to +do it collectively and coordination and + + align:start position:0% +do it collectively and coordination and + + + align:start position:0% +do it collectively and coordination and +that's true of every blockchain that you + + align:start position:0% +that's true of every blockchain that you + + + align:start position:0% +that's true of every blockchain that you +can think about governance relates to + + align:start position:0% +can think about governance relates to + + + align:start position:0% +can think about governance relates to +coordination and collective action + + align:start position:0% +coordination and collective action + + + align:start position:0% +coordination and collective action +issues and then security and scalability + + align:start position:0% +issues and then security and scalability + + + align:start position:0% +issues and then security and scalability +these two lines are not in any of the + + align:start position:0% +these two lines are not in any of the + + + align:start position:0% +these two lines are not in any of the +readings but they try to capture what + + align:start position:0% +readings but they try to capture what + + + align:start position:0% +readings but they try to capture what +and depending them on the slope of the + + align:start position:0% +and depending them on the slope of the + + + align:start position:0% +and depending them on the slope of the +two lines you might say that a market + + align:start position:0% +two lines you might say that a market + + + align:start position:0% +two lines you might say that a market +might tend towards more centralization + + align:start position:0% +might tend towards more centralization + + + align:start position:0% +might tend towards more centralization +in theory if I change the slope it would + + align:start position:0% +in theory if I change the slope it would + + + align:start position:0% +in theory if I change the slope it would +be further to the decentralized side + + align:start position:0% +be further to the decentralized side + + + align:start position:0% +be further to the decentralized side +right if the cost of decentralization is + + align:start position:0% +right if the cost of decentralization is + + + align:start position:0% +right if the cost of decentralization is +a lower slope and the cost of + + align:start position:0% +a lower slope and the cost of + + + align:start position:0% +a lower slope and the cost of +centralization is higher we will tend + + align:start position:0% +centralization is higher we will tend + + + align:start position:0% +centralization is higher we will tend +more towards decentralization so it's + + align:start position:0% +more towards decentralization so it's + + + align:start position:0% +more towards decentralization so it's +just a way that to visualize here are + + align:start position:0% +just a way that to visualize here are + + + align:start position:0% +just a way that to visualize here are +the costs of centralization which are + + align:start position:0% +the costs of centralization which are + + + align:start position:0% +the costs of centralization which are +basically capture rents and single point + + align:start position:0% +basically capture rents and single point + + + align:start position:0% +basically capture rents and single point +of failure not that there aren't other + + align:start position:0% +of failure not that there aren't other + + + align:start position:0% +of failure not that there aren't other +costs of centralization here are the + + align:start position:0% +costs of centralization here are the + + + align:start position:0% +costs of centralization here are the +costs of decentralization I think in + + align:start position:0% +costs of decentralization I think in + + + align:start position:0% +costs of decentralization I think in +each one of the applications when you're + + align:start position:0% +each one of the applications when you're + + + align:start position:0% +each one of the applications when you're +thinking of use cases it's worthy this + + align:start position:0% +thinking of use cases it's worthy this + + + align:start position:0% +thinking of use cases it's worthy this +is kind of a core thing well this + + align:start position:0% +is kind of a core thing well this + + + align:start position:0% +is kind of a core thing well this +application lend itself to a low slope + + align:start position:0% +application lend itself to a low slope + + + align:start position:0% +application lend itself to a low slope +decentralization curve and a high slope + + align:start position:0% +decentralization curve and a high slope + + + align:start position:0% +decentralization curve and a high slope +centralization curve + + align:start position:0% +centralization curve + + + align:start position:0% +centralization curve +are there a lot of economic rents so + + align:start position:0% +are there a lot of economic rents so + + + align:start position:0% +are there a lot of economic rents so +their real problems with single points + + align:start position:0% +their real problems with single points + + + align:start position:0% +their real problems with single points +of failure and capture and if it's a + + align:start position:0% +of failure and capture and if it's a + + + align:start position:0% +of failure and capture and if it's a +slow slope decentralization curve + + align:start position:0% +slow slope decentralization curve + + + align:start position:0% +slow slope decentralization curve +meaning there's not much cost to the + + align:start position:0% +meaning there's not much cost to the + + + align:start position:0% +meaning there's not much cost to the +governance coordination and scalability + + align:start position:0% +governance coordination and scalability + + + align:start position:0% +governance coordination and scalability +issues and you're going to be more + + align:start position:0% +issues and you're going to be more + + + align:start position:0% +issues and you're going to be more +towards decentralization that this isn't + + align:start position:0% +towards decentralization that this isn't + + + align:start position:0% +towards decentralization that this isn't +any reading or book it's just you know a + + align:start position:0% +any reading or book it's just you know a + + + align:start position:0% +any reading or book it's just you know a +shot at trying to visualize it Shawn + + align:start position:0% +shot at trying to visualize it Shawn + + + align:start position:0% +shot at trying to visualize it Shawn +any question + + align:start position:0% + + + + align:start position:0% + +John's question is why are the privacy + + align:start position:0% +John's question is why are the privacy + + + align:start position:0% +John's question is why are the privacy +coins forked + + align:start position:0% +coins forked + + + align:start position:0% +coins forked +not all of them but many of them are + + align:start position:0% +not all of them but many of them are + + + align:start position:0% +not all of them but many of them are +forked off of Bitcoin or one of the + + align:start position:0% +forked off of Bitcoin or one of the + + + align:start position:0% +forked off of Bitcoin or one of the +major coins medoras you want to say did + + align:start position:0% +major coins medoras you want to say did + + + align:start position:0% +major coins medoras you want to say did +you you have one privacy coin high + + align:start position:0% +you you have one privacy coin high + + + align:start position:0% +you you have one privacy coin high +quality code so you can build up on it + + align:start position:0% +quality code so you can build up on it + + + align:start position:0% +quality code so you can build up on it +so it's natural to like add privacy on + + align:start position:0% +so it's natural to like add privacy on + + + align:start position:0% +so it's natural to like add privacy on +top of Bitcoin in your fork rather than + + align:start position:0% +top of Bitcoin in your fork rather than + + + align:start position:0% +top of Bitcoin in your fork rather than +write it from scratch medoras is the + + align:start position:0% +write it from scratch medoras is the + + + align:start position:0% +write it from scratch medoras is the +answering is there's something that's + + align:start position:0% +answering is there's something that's + + + align:start position:0% +answering is there's something that's +freely available the Bitcoin core code + + align:start position:0% +freely available the Bitcoin core code + + + align:start position:0% +freely available the Bitcoin core code +it's actually under a copyright license + + align:start position:0% +it's actually under a copyright license + + + align:start position:0% +it's actually under a copyright license +here at MIT which makes it free that was + + align:start position:0% +here at MIT which makes it free that was + + + align:start position:0% +here at MIT which makes it free that was +Satoshi nakamoto's decision it wasn't + + align:start position:0% +Satoshi nakamoto's decision it wasn't + + + align:start position:0% +Satoshi nakamoto's decision it wasn't +that well maybe Nakamoto does work here + + align:start position:0% + + + + align:start position:0% + +the clue but it's it's it's been + + align:start position:0% +the clue but it's it's it's been + + + align:start position:0% +the clue but it's it's it's been +developed and it's knocked around as I + + align:start position:0% +developed and it's knocked around as I + + + align:start position:0% +developed and it's knocked around as I +call it in the proverbial swamp I mean + + align:start position:0% +call it in the proverbial swamp I mean + + + align:start position:0% +call it in the proverbial swamp I mean +with all these attack viruses and so + + align:start position:0% +with all these attack viruses and so + + + align:start position:0% +with all these attack viruses and so +forth and Soma doors are saying build + + align:start position:0% +forth and Soma doors are saying build + + + align:start position:0% +forth and Soma doors are saying build +off of that and basically get that code + + align:start position:0% +off of that and basically get that code + + + align:start position:0% +off of that and basically get that code +for free and then fork that so the + + align:start position:0% +for free and then fork that so the + + + align:start position:0% +for free and then fork that so the +challenge is we talked about it a + + align:start position:0% +challenge is we talked about it a + + + align:start position:0% +challenge is we talked about it a +performance scalability efficiency + + align:start position:0% +performance scalability efficiency + + + align:start position:0% +performance scalability efficiency +privacy security what there was less + + align:start position:0% +privacy security what there was less + + + align:start position:0% +privacy security what there was less +talk about was interoperability + + align:start position:0% +talk about was interoperability + + + align:start position:0% +talk about was interoperability +governance and collective action and I'm + + align:start position:0% +governance and collective action and I'm + + + align:start position:0% +governance and collective action and I'm +going to dig into those two more because + + align:start position:0% +going to dig into those two more because + + + align:start position:0% +going to dig into those two more because +it feels like that's worthwhile I also + + align:start position:0% +it feels like that's worthwhile I also + + + align:start position:0% +it feels like that's worthwhile I also +believe that the first bucket + + align:start position:0% +believe that the first bucket + + + align:start position:0% +believe that the first bucket +performance and privacy buckets are more + + align:start position:0% +performance and privacy buckets are more + + + align:start position:0% +performance and privacy buckets are more +susceptible to fixes though that might + + align:start position:0% +susceptible to fixes though that might + + + align:start position:0% +susceptible to fixes though that might +take three or five or even eight or ten + + align:start position:0% +take three or five or even eight or ten + + + align:start position:0% +take three or five or even eight or ten +years to happen I think they're more + + align:start position:0% +years to happen I think they're more + + + align:start position:0% +years to happen I think they're more +susceptible to the sort of bright men + + align:start position:0% +susceptible to the sort of bright men + + + align:start position:0% +susceptible to the sort of bright men +and women that are in these fields + + align:start position:0% +and women that are in these fields + + + align:start position:0% +and women that are in these fields +addressing themselves to the computer + + align:start position:0% +addressing themselves to the computer + + + align:start position:0% +addressing themselves to the computer +science and cryptography of the space + + align:start position:0% +science and cryptography of the space + + + align:start position:0% +science and cryptography of the space +whereas governance and collective action + + align:start position:0% +whereas governance and collective action + + + align:start position:0% +whereas governance and collective action +might be solvable but I think it's it's + + align:start position:0% +might be solvable but I think it's it's + + + align:start position:0% +might be solvable but I think it's it's +sort of inherent in the human element + + align:start position:0% +sort of inherent in the human element + + + align:start position:0% +sort of inherent in the human element +and the commercial arrangements that + + align:start position:0% +and the commercial arrangements that + + + align:start position:0% +and the commercial arrangements that +governance and collective action or the + + align:start position:0% +governance and collective action or the + + + align:start position:0% +governance and collective action or the +harder of these four buckets that's just + + align:start position:0% +harder of these four buckets that's just + + + align:start position:0% +harder of these four buckets that's just +one person's read of it but we'll go + + align:start position:0% +one person's read of it but we'll go + + + align:start position:0% +one person's read of it but we'll go +through some of the reasons as well why + + align:start position:0% +through some of the reasons as well why + + + align:start position:0% +through some of the reasons as well why +I kind of I get it to that view + + align:start position:0% +I kind of I get it to that view + + + align:start position:0% +I kind of I get it to that view +there's also commercial use case + + align:start position:0% +there's also commercial use case + + + align:start position:0% +there's also commercial use case +challenges we're not going to dig into + + align:start position:0% +challenges we're not going to dig into + + + align:start position:0% +challenges we're not going to dig into +that much here that's mostly the second + + align:start position:0% +that much here that's mostly the second + + + align:start position:0% +that much here that's mostly the second +half of the semester but I just wanted + + align:start position:0% +half of the semester but I just wanted + + + align:start position:0% +half of the semester but I just wanted +to mention that's a real thing that a + + align:start position:0% +to mention that's a real thing that a + + + align:start position:0% +to mention that's a real thing that a +lot of folks are saying well I have to + + align:start position:0% +lot of folks are saying well I have to + + + align:start position:0% +lot of folks are saying well I have to +make sure that this is the best + + align:start position:0% +make sure that this is the best + + + align:start position:0% +make sure that this is the best +commercial application and so forth and + + align:start position:0% +commercial application and so forth and + + + align:start position:0% +commercial application and so forth and +can I make money I mean ultimately on it + + align:start position:0% +can I make money I mean ultimately on it + + + align:start position:0% +can I make money I mean ultimately on it +and then we are next week going to talk + + align:start position:0% +and then we are next week going to talk + + + align:start position:0% +and then we are next week going to talk +about the public policy issues and + + align:start position:0% +about the public policy issues and + + + align:start position:0% +about the public policy issues and +challenges and they all kind of + + align:start position:0% +challenges and they all kind of + + + align:start position:0% +challenges and they all kind of +intersect in a way as well + + align:start position:0% +intersect in a way as well + + + align:start position:0% +intersect in a way as well +so Vitalik buddha ran I think there was + + align:start position:0% +so Vitalik buddha ran I think there was + + + align:start position:0% +so Vitalik buddha ran I think there was +a medium post I had you all read bow do + + align:start position:0% +a medium post I had you all read bow do + + + align:start position:0% +a medium post I had you all read bow do +you want me to tell you tell us a little + + align:start position:0% +you want me to tell you tell us a little + + + align:start position:0% +you want me to tell you tell us a little +bit about what you think is metallic not + + align:start position:0% +bit about what you think is metallic not + + + align:start position:0% +bit about what you think is metallic not +only a brilliant computer scientist but + + align:start position:0% +only a brilliant computer scientist but + + + align:start position:0% +only a brilliant computer scientist but +does he get the economics of this right + + align:start position:0% +does he get the economics of this right + + + align:start position:0% +does he get the economics of this right +or you think he's off you're gonna be on + + align:start position:0% +or you think he's off you're gonna be on + + + align:start position:0% +or you think he's off you're gonna be on +there's no right answer I know people + + align:start position:0% +there's no right answer I know people + + + align:start position:0% +there's no right answer I know people +that feel both ends of the spectrum + + align:start position:0% +that feel both ends of the spectrum + + + align:start position:0% +that feel both ends of the spectrum +about his trilemma so I'm setting you up + + align:start position:0% +about his trilemma so I'm setting you up + + + align:start position:0% +about his trilemma so I'm setting you up +that old saying about what how many of + + align:start position:0% +that old saying about what how many of + + + align:start position:0% +that old saying about what how many of +you have ever hired a contractor to fix + + align:start position:0% +you have ever hired a contractor to fix + + + align:start position:0% +you have ever hired a contractor to fix +something in your kitchen or renovate + + align:start position:0% +something in your kitchen or renovate + + + align:start position:0% +something in your kitchen or renovate +renovate something I mean I have them a + + align:start position:0% +renovate something I mean I have them a + + + align:start position:0% +renovate something I mean I have them a +little older right you know the old saw + + align:start position:0% +little older right you know the old saw + + + align:start position:0% +little older right you know the old saw +that it's good quick cheap but you can't + + align:start position:0% +that it's good quick cheap but you can't + + + align:start position:0% +that it's good quick cheap but you can't +you can't get all three you can only get + + align:start position:0% +you can't get all three you can only get + + + align:start position:0% +you can't get all three you can only get +two out of three that's sort of the + + align:start position:0% +two out of three that's sort of the + + + align:start position:0% +two out of three that's sort of the +contractor dilemma but but what do you + + align:start position:0% +contractor dilemma but but what do you + + + align:start position:0% +contractor dilemma but but what do you +think do you think he's right or do you + + align:start position:0% +think do you think he's right or do you + + + align:start position:0% +think do you think he's right or do you +think you could maybe overtime get all + + align:start position:0% +think you could maybe overtime get all + + + align:start position:0% +think you could maybe overtime get all +three good cheap quick scalable + + align:start position:0% +three good cheap quick scalable + + + align:start position:0% +three good cheap quick scalable +decentralized and secure my very + + align:start position:0% +decentralized and secure my very + + + align:start position:0% +decentralized and secure my very +unsophisticated the other side just to + + align:start position:0% +unsophisticated the other side just to + + + align:start position:0% +unsophisticated the other side just to +have some fun in some debate sure yeah + + align:start position:0% +have some fun in some debate sure yeah + + + align:start position:0% +have some fun in some debate sure yeah +go out at Leonardo that systems have had + + align:start position:0% +go out at Leonardo that systems have had + + + align:start position:0% +go out at Leonardo that systems have had +to develop so they mention for example + + align:start position:0% +to develop so they mention for example + + + align:start position:0% +to develop so they mention for example +visa has at sixty years + + align:start position:0% +visa has at sixty years + + + align:start position:0% +visa has at sixty years +develop a system that works some of + + align:start position:0% +develop a system that works some of + + + align:start position:0% +develop a system that works some of +those currencies and at three four or + + align:start position:0% +those currencies and at three four or + + + align:start position:0% +those currencies and at three four or +five years number his personal opinion + + align:start position:0% +five years number his personal opinion + + + align:start position:0% +five years number his personal opinion +the tax was like less than five percent + + align:start position:0% +the tax was like less than five percent + + + align:start position:0% +the tax was like less than five percent +they would not overcome I don't know if + + align:start position:0% +they would not overcome I don't know if + + + align:start position:0% +they would not overcome I don't know if +that is like a wrong but I think the + + align:start position:0% +that is like a wrong but I think the + + + align:start position:0% +that is like a wrong but I think the +fact that this is a new technology yes + + align:start position:0% +fact that this is a new technology yes + + + align:start position:0% +fact that this is a new technology yes +maybe Vitalik is right that only 5% + + align:start position:0% +maybe Vitalik is right that only 5% + + + align:start position:0% +maybe Vitalik is right that only 5% +maybe only one person + + align:start position:0% +maybe only one person + + + align:start position:0% +maybe only one person +that will succeed but to say that no one + + align:start position:0% +that will succeed but to say that no one + + + align:start position:0% +that will succeed but to say that no one +will deal with these three points in in + + align:start position:0% +will deal with these three points in in + + + align:start position:0% +will deal with these three points in in +a simultaneous satisfactory way and + + align:start position:0% +a simultaneous satisfactory way and + + + align:start position:0% +a simultaneous satisfactory way and +ultimately it has to be satisfactory in + + align:start position:0% +ultimately it has to be satisfactory in + + + align:start position:0% +ultimately it has to be satisfactory in +a commercial way you know taking the + + align:start position:0% +a commercial way you know taking the + + + align:start position:0% +a commercial way you know taking the +risk and trade-offs so Leonardo takes + + align:start position:0% +risk and trade-offs so Leonardo takes + + + align:start position:0% +risk and trade-offs so Leonardo takes +the other side anybody want to say why + + align:start position:0% +the other side anybody want to say why + + + align:start position:0% +the other side anybody want to say why +Leonardo Hugo were you which side are + + align:start position:0% +Leonardo Hugo were you which side are + + + align:start position:0% +Leonardo Hugo were you which side are +you taking Leonardo's side or Vitalik + + align:start position:0% +you taking Leonardo's side or Vitalik + + + align:start position:0% +you taking Leonardo's side or Vitalik +side suffering the middle okay so I + + align:start position:0% +side suffering the middle okay so I + + + align:start position:0% +side suffering the middle okay so I +think that there is a trade-off but I + + align:start position:0% +think that there is a trade-off but I + + + align:start position:0% +think that there is a trade-off but I +agree that it might take time to improve + + align:start position:0% +agree that it might take time to improve + + + align:start position:0% +agree that it might take time to improve +all three simultaneously I mean one + + align:start position:0% +all three simultaneously I mean one + + + align:start position:0% +all three simultaneously I mean one +thing that happened just this last week + + align:start position:0% +thing that happened just this last week + + + align:start position:0% +thing that happened just this last week +in Bitcoin was there was a vulnerability + + align:start position:0% +in Bitcoin was there was a vulnerability + + + align:start position:0% +in Bitcoin was there was a vulnerability +discovered and like as somebody who + + align:start position:0% +discovered and like as somebody who + + + align:start position:0% +discovered and like as somebody who +doesn't know how to check the codebase + + align:start position:0% +doesn't know how to check the codebase + + + align:start position:0% +doesn't know how to check the codebase +really like I'm not a computer science + + align:start position:0% +really like I'm not a computer science + + + align:start position:0% +really like I'm not a computer science +person so I'm never like checked for + + align:start position:0% +person so I'm never like checked for + + + align:start position:0% +person so I'm never like checked for +bugs or anything that I want to do that + + align:start position:0% +bugs or anything that I want to do that + + + align:start position:0% +bugs or anything that I want to do that +I kind of just take the software as it + + align:start position:0% +I kind of just take the software as it + + + align:start position:0% +I kind of just take the software as it +stands and unload it and install it and + + align:start position:0% +stands and unload it and install it and + + + align:start position:0% +stands and unload it and install it and +when they say I need to update my + + align:start position:0% +when they say I need to update my + + + align:start position:0% +when they say I need to update my +software because there's a bug I'll + + align:start position:0% +software because there's a bug I'll + + + align:start position:0% +software because there's a bug I'll +update the software there's a bug and + + align:start position:0% +update the software there's a bug and + + + align:start position:0% +update the software there's a bug and +that kind of feels like more of a + + align:start position:0% +that kind of feels like more of a + + + align:start position:0% +that kind of feels like more of a +centralized system but you're getting + + align:start position:0% +centralized system but you're getting + + + align:start position:0% +centralized system but you're getting +that security but then the + + align:start position:0% +that security but then the + + + align:start position:0% +that security but then the +decentralization comes something from + + align:start position:0% +decentralization comes something from + + + align:start position:0% +decentralization comes something from +the fact that the network is still + + align:start position:0% +the fact that the network is still + + + align:start position:0% +the fact that the network is still +spread out over something you know it's + + align:start position:0% +spread out over something you know it's + + + align:start position:0% +spread out over something you know it's +so like there are trade-offs that I + + align:start position:0% +so like there are trade-offs that I + + + align:start position:0% +so like there are trade-offs that I +think you can kind of build on one and + + align:start position:0% +think you can kind of build on one and + + + align:start position:0% +think you can kind of build on one and +then climb another cliff like kind of + + align:start position:0% +then climb another cliff like kind of + + + align:start position:0% +then climb another cliff like kind of +build on each but not at the same time + + align:start position:0% + + + + align:start position:0% + +I'm probably an optimist enough on the + + align:start position:0% +I'm probably an optimist enough on the + + + align:start position:0% +I'm probably an optimist enough on the +human condition and that the + + align:start position:0% +human condition and that the + + + align:start position:0% +human condition and that the +technologist will solve more than + + align:start position:0% +technologist will solve more than + + + align:start position:0% +technologist will solve more than +metallics so I'm not saying I'm all the + + align:start position:0% +metallics so I'm not saying I'm all the + + + align:start position:0% +metallics so I'm not saying I'm all the +way we're Leonardo or wherever yeah + + align:start position:0% +way we're Leonardo or wherever yeah + + + align:start position:0% +way we're Leonardo or wherever yeah +there would be but I'm probably closer + + align:start position:0% +there would be but I'm probably closer + + + align:start position:0% +there would be but I'm probably closer +to Leonardo than to vitalik but that's + + align:start position:0% +to Leonardo than to vitalik but that's + + + align:start position:0% +to Leonardo than to vitalik but that's +just my points of view I also find an + + align:start position:0% +just my points of view I also find an + + + align:start position:0% +just my points of view I also find an +interesting of it's all right if I say + + align:start position:0% +interesting of it's all right if I say + + + align:start position:0% +interesting of it's all right if I say +Hugo's an engineering doctoral student + + align:start position:0% +Hugo's an engineering doctoral student + + + align:start position:0% +Hugo's an engineering doctoral student +here and yet he's not checking the code + + align:start position:0% +here and yet he's not checking the code + + + align:start position:0% +here and yet he's not checking the code +not any right because right so there's a + + align:start position:0% +not any right because right so there's a + + + align:start position:0% +not any right because right so there's a +trust issue that in the marketplace the + + align:start position:0% +trust issue that in the marketplace the + + + align:start position:0% +trust issue that in the marketplace the +trust of the code we also trust Facebook + + align:start position:0% +trust of the code we also trust Facebook + + + align:start position:0% +trust of the code we also trust Facebook +and Dropbox and and and broadly speaking + + align:start position:0% +and Dropbox and and and broadly speaking + + + align:start position:0% +and Dropbox and and and broadly speaking +the Internet as well Priya + + align:start position:0% +the Internet as well Priya + + + align:start position:0% +the Internet as well Priya +there are several examples throughout + + align:start position:0% +there are several examples throughout + + + align:start position:0% +there are several examples throughout +the evolution of human interaction where + + align:start position:0% +the evolution of human interaction where + + + align:start position:0% +the evolution of human interaction where +these three things have been sorted so + + align:start position:0% +these three things have been sorted so + + + align:start position:0% +these three things have been sorted so +it might not be that and in some systems + + align:start position:0% +it might not be that and in some systems + + + align:start position:0% +it might not be that and in some systems +at any one time all these three nodes + + align:start position:0% +at any one time all these three nodes + + + align:start position:0% +at any one time all these three nodes +are working right like four are + + align:start position:0% +are working right like four are + + + align:start position:0% +are working right like four are +currently in existence there are moments + + align:start position:0% +currently in existence there are moments + + + align:start position:0% +currently in existence there are moments +of vulnerability yes but then you catch + + align:start position:0% +of vulnerability yes but then you catch + + + align:start position:0% +of vulnerability yes but then you catch +it sooner or later so I feel like it's + + align:start position:0% +it sooner or later so I feel like it's + + + align:start position:0% +it sooner or later so I feel like it's +maybe not it's about having it all + + align:start position:0% +maybe not it's about having it all + + + align:start position:0% +maybe not it's about having it all +perfect right now versus will you get to + + align:start position:0% +perfect right now versus will you get to + + + align:start position:0% +perfect right now versus will you get to +a point where all three are mostly in + + align:start position:0% +a point where all three are mostly in + + + align:start position:0% +a point where all three are mostly in +place and working like how Priya said + + align:start position:0% +place and working like how Priya said + + + align:start position:0% +place and working like how Priya said +working enough right it doesn't have to + + align:start position:0% +working enough right it doesn't have to + + + align:start position:0% +working enough right it doesn't have to +be scalable to the place where it's + + align:start position:0% +be scalable to the place where it's + + + align:start position:0% +be scalable to the place where it's +millions of transactions a second but + + align:start position:0% +millions of transactions a second but + + + align:start position:0% +millions of transactions a second but +maybe it needs to be faster than seven + + align:start position:0% +maybe it needs to be faster than seven + + + align:start position:0% +maybe it needs to be faster than seven +or ten transactions a second or a theory + + align:start position:0% +or ten transactions a second or a theory + + + align:start position:0% +or ten transactions a second or a theory +I'm 20 transactions a second we had I + + align:start position:0% +I'm 20 transactions a second we had I + + + align:start position:0% +I'm 20 transactions a second we had I +should also remind everybody Tuesday + + align:start position:0% +should also remind everybody Tuesday + + + align:start position:0% +should also remind everybody Tuesday +nights we have dinner Simon Johnson + + align:start position:0% +nights we have dinner Simon Johnson + + + align:start position:0% +nights we have dinner Simon Johnson +treats every Tuesday night it's not + + align:start position:0% +treats every Tuesday night it's not + + + align:start position:0% +treats every Tuesday night it's not +required to come but it's 5:30 to 7:00 + + align:start position:0% +required to come but it's 5:30 to 7:00 + + + align:start position:0% +required to come but it's 5:30 to 7:00 +that we have an outside speaker around + + align:start position:0% +that we have an outside speaker around + + + align:start position:0% +that we have an outside speaker around +the block chain space and you're welcome + + align:start position:0% +the block chain space and you're welcome + + + align:start position:0% +the block chain space and you're welcome +to come Michelle is here who Michelle + + align:start position:0% +to come Michelle is here who Michelle + + + align:start position:0% +to come Michelle is here who Michelle +Fiorenza anybody that wants to come but + + align:start position:0% +Fiorenza anybody that wants to come but + + + align:start position:0% +Fiorenza anybody that wants to come but +this past week we had somebody speaking + + align:start position:0% +this past week we had somebody speaking + + + align:start position:0% +this past week we had somebody speaking +about the scalability issues and when + + align:start position:0% +about the scalability issues and when + + + align:start position:0% +about the scalability issues and when +his company did a twenty five million + + align:start position:0% +his company did a twenty five million + + + align:start position:0% +his company did a twenty five million +dollar initial coin offering the day of + + align:start position:0% +dollar initial coin offering the day of + + + align:start position:0% +dollar initial coin offering the day of +the offering which only had 40 to 50 + + align:start position:0% +the offering which only had 40 to 50 + + + align:start position:0% +the offering which only had 40 to 50 +thousand purchasers so forty or fifty + + align:start position:0% +thousand purchasers so forty or fifty + + + align:start position:0% +thousand purchasers so forty or fifty +thousand purchasers on that day that + + align:start position:0% +thousand purchasers on that day that + + + align:start position:0% +thousand purchasers on that day that +means the smart contract had to be + + align:start position:0% +means the smart contract had to be + + + align:start position:0% +means the smart contract had to be +triggered numerous times that day took + + align:start position:0% +triggered numerous times that day took + + + align:start position:0% +triggered numerous times that day took +over a third of the entire aetherium + + align:start position:0% +over a third of the entire aetherium + + + align:start position:0% +over a third of the entire aetherium +network on that day and it's sluggish + + align:start position:0% +network on that day and it's sluggish + + + align:start position:0% +network on that day and it's sluggish +and just to close and settle on his + + align:start position:0% +and just to close and settle on his + + + align:start position:0% +and just to close and settle on his +initial coin offering I was saying jeez + + align:start position:0% +initial coin offering I was saying jeez + + + align:start position:0% +initial coin offering I was saying jeez +that that's not the scalability you know + + align:start position:0% +that that's not the scalability you know + + + align:start position:0% +that that's not the scalability you know +we want so we know that's where we are + + align:start position:0% +we want so we know that's where we are + + + align:start position:0% +we want so we know that's where we are +today + + align:start position:0% +today + + + align:start position:0% +today +visa runs around 20 to 30,000 + + align:start position:0% +visa runs around 20 to 30,000 + + + align:start position:0% +visa runs around 20 to 30,000 +transactions a second DTCC which settles + + align:start position:0% +transactions a second DTCC which settles + + + align:start position:0% +transactions a second DTCC which settles +all the stock and equity trades here in + + align:start position:0% +all the stock and equity trades here in + + + align:start position:0% +all the stock and equity trades here in +the US has to be available to transact + + align:start position:0% +the US has to be available to transact + + + align:start position:0% +the US has to be available to transact +at least a hundred thousand a second + + align:start position:0% +at least a hundred thousand a second + + + align:start position:0% +at least a hundred thousand a second +most seconds it's five or ten or some + + align:start position:0% +most seconds it's five or ten or some + + + align:start position:0% +most seconds it's five or ten or some +seconds it's thirty thousand but the + + align:start position:0% +seconds it's thirty thousand but the + + + align:start position:0% +seconds it's thirty thousand but the +Securities and Exchange Commission says + + align:start position:0% +Securities and Exchange Commission says + + + align:start position:0% +Securities and Exchange Commission says +no you have to be rated for four times + + align:start position:0% +no you have to be rated for four times + + + align:start position:0% +no you have to be rated for four times +your average roughly so this gives you a + + align:start position:0% +your average roughly so this gives you a + + + align:start position:0% +your average roughly so this gives you a +sense of the scalability issues just in + + align:start position:0% +sense of the scalability issues just in + + + align:start position:0% +sense of the scalability issues just in +the current environment if one layer is + + align:start position:0% +the current environment if one layer is + + + align:start position:0% +the current environment if one layer is +the Internet of Things on top of it + + align:start position:0% +the Internet of Things on top of it + + + align:start position:0% +the Internet of Things on top of it +there's somewhere and I've heard + + align:start position:0% +there's somewhere and I've heard + + + align:start position:0% +there's somewhere and I've heard +different estimates of eight to ten + + align:start position:0% +different estimates of eight to ten + + + align:start position:0% +different estimates of eight to ten +billion devices currently connected to + + align:start position:0% +billion devices currently connected to + + + align:start position:0% +billion devices currently connected to +the Internet and that's likely to grow + + align:start position:0% +the Internet and that's likely to grow + + + align:start position:0% +the Internet and that's likely to grow +as more refrigerators and street lights + + align:start position:0% +as more refrigerators and street lights + + + align:start position:0% +as more refrigerators and street lights +and traffic lights are tied into the + + align:start position:0% +and traffic lights are tied into the + + + align:start position:0% +and traffic lights are tied into the +Internet in the next five or ten years + + align:start position:0% +Internet in the next five or ten years + + + align:start position:0% +Internet in the next five or ten years +to fifty to a hundred billion devices + + align:start position:0% +to fifty to a hundred billion devices + + + align:start position:0% +to fifty to a hundred billion devices +tied to the Internet + + align:start position:0% +tied to the Internet + + + align:start position:0% +tied to the Internet +if they start communicating to each + + align:start position:0% +if they start communicating to each + + + align:start position:0% +if they start communicating to each +other will it be a blockchain for + + align:start position:0% +other will it be a blockchain for + + + align:start position:0% +other will it be a blockchain for +Internet of Things can't do it at these + + align:start position:0% +Internet of Things can't do it at these + + + align:start position:0% +Internet of Things can't do it at these +types of scaling numbers or can you do + + align:start position:0% +types of scaling numbers or can you do + + + align:start position:0% +types of scaling numbers or can you do +it in some alternative method proof of + + align:start position:0% +it in some alternative method proof of + + + align:start position:0% +it in some alternative method proof of +work is also has a bunch of energy + + align:start position:0% +work is also has a bunch of energy + + + align:start position:0% +work is also has a bunch of energy +consumption we didn't have that a lot in + + align:start position:0% +consumption we didn't have that a lot in + + + align:start position:0% +consumption we didn't have that a lot in +the writing we chose not to put a bunch + + align:start position:0% +the writing we chose not to put a bunch + + + align:start position:0% +the writing we chose not to put a bunch +of that in the Geneva report one + + align:start position:0% +of that in the Geneva report one + + + align:start position:0% +of that in the Geneva report one +estimate is that it's 200 million + + align:start position:0% +estimate is that it's 200 million + + + align:start position:0% +estimate is that it's 200 million +kilowatt hours per day that's equivalent + + align:start position:0% +kilowatt hours per day that's equivalent + + + align:start position:0% +kilowatt hours per day that's equivalent +about seven million US homes on average + + align:start position:0% +about seven million US homes on average + + + align:start position:0% +about seven million US homes on average +just give you a rough didge economists + + align:start position:0% +just give you a rough didge economists + + + align:start position:0% +just give you a rough didge economists +estimate that's one third of 1% of all + + align:start position:0% +estimate that's one third of 1% of all + + + align:start position:0% +estimate that's one third of 1% of all +the world's electricity just a scale + + align:start position:0% +the world's electricity just a scale + + + align:start position:0% +the world's electricity just a scale +scale it if you now you can have a nice + + align:start position:0% +scale it if you now you can have a nice + + + align:start position:0% +scale it if you now you can have a nice +dinner you know dinner party + + align:start position:0% +dinner you know dinner party + + + align:start position:0% +dinner you know dinner party +conversation point it's the it's the + + align:start position:0% +conversation point it's the it's the + + + align:start position:0% +conversation point it's the it's the +electricity of the country of Austria is + + align:start position:0% +electricity of the country of Austria is + + + align:start position:0% +electricity of the country of Austria is +anybody Austrian no I just was you know + + align:start position:0% +anybody Austrian no I just was you know + + + align:start position:0% +anybody Austrian no I just was you know +so it's that's one set of trade-offs of + + align:start position:0% +so it's that's one set of trade-offs of + + + align:start position:0% +so it's that's one set of trade-offs of +proof-of-work as well but it also costs + + align:start position:0% +proof-of-work as well but it also costs + + + align:start position:0% +proof-of-work as well but it also costs +a lot of + + align:start position:0% +a lot of + + + align:start position:0% +a lot of +to run the banking system so I think + + align:start position:0% +to run the banking system so I think + + + align:start position:0% +to run the banking system so I think +that when somebody says well it's + + align:start position:0% +that when somebody says well it's + + + align:start position:0% +that when somebody says well it's +terrible it's challenging all this + + align:start position:0% +terrible it's challenging all this + + + align:start position:0% +terrible it's challenging all this +electric costs yes we always want to + + align:start position:0% +electric costs yes we always want to + + + align:start position:0% +electric costs yes we always want to +lower costs but the US financial system + + align:start position:0% +lower costs but the US financial system + + + align:start position:0% +lower costs but the US financial system +is seven and a half percent of our + + align:start position:0% +is seven and a half percent of our + + + align:start position:0% +is seven and a half percent of our +economy and cost one and a half trillion + + align:start position:0% +economy and cost one and a half trillion + + + align:start position:0% +economy and cost one and a half trillion +dollars so the payment system around the + + align:start position:0% +dollars so the payment system around the + + + align:start position:0% +dollars so the payment system around the +globe cost a half a percent to a percent + + align:start position:0% +globe cost a half a percent to a percent + + + align:start position:0% +globe cost a half a percent to a percent +of the global economy which is more than + + align:start position:0% +of the global economy which is more than + + + align:start position:0% +of the global economy which is more than +one-third of 1% of the world electricity + + align:start position:0% +one-third of 1% of the world electricity + + + align:start position:0% +one-third of 1% of the world electricity +cost so I'm just putting it in its back + + align:start position:0% +cost so I'm just putting it in its back + + + align:start position:0% +cost so I'm just putting it in its back +to this question of which cost of trust + + align:start position:0% +to this question of which cost of trust + + + align:start position:0% +to this question of which cost of trust +which costs neither a maximalist or a + + align:start position:0% +which costs neither a maximalist or a + + + align:start position:0% +which costs neither a maximalist or a +minimalist as you recall so what are + + align:start position:0% +minimalist as you recall so what are + + + align:start position:0% +minimalist as you recall so what are +some of the alternatives and we're not + + align:start position:0% +some of the alternatives and we're not + + + align:start position:0% +some of the alternatives and we're not +going to dig into each of these side + + align:start position:0% +going to dig into each of these side + + + align:start position:0% +going to dig into each of these side +chains shorting layer 2 payment channels + + align:start position:0% +chains shorting layer 2 payment channels + + + align:start position:0% +chains shorting layer 2 payment channels +anybody want to take a crack they're not + + align:start position:0% +anybody want to take a crack they're not + + + align:start position:0% +anybody want to take a crack they're not +all the identical + + align:start position:0% +all the identical + + + align:start position:0% +all the identical +it's a medoras and I had a conversation + + align:start position:0% +it's a medoras and I had a conversation + + + align:start position:0% +it's a medoras and I had a conversation +earlier today said I could even get my + + align:start position:0% +earlier today said I could even get my + + + align:start position:0% +earlier today said I could even get my +head around because I get confused but + + align:start position:0% +head around because I get confused but + + + align:start position:0% +head around because I get confused but +does anybody want to give the basic we + + align:start position:0% +does anybody want to give the basic we + + + align:start position:0% +does anybody want to give the basic we +were talking about it earlier the basic + + align:start position:0% +were talking about it earlier the basic + + + align:start position:0% +were talking about it earlier the basic +tenets cuz you had a reading about the + + align:start position:0% +tenets cuz you had a reading about the + + + align:start position:0% +tenets cuz you had a reading about the +Lightning Network as to what's what's + + align:start position:0% +Lightning Network as to what's what's + + + align:start position:0% +Lightning Network as to what's what's +the economic thing and technical thing + + align:start position:0% +the economic thing and technical thing + + + align:start position:0% +the economic thing and technical thing +that's being attempted in all four of + + align:start position:0% +that's being attempted in all four of + + + align:start position:0% +that's being attempted in all four of +these types of things with James was + + align:start position:0% +these types of things with James was + + + align:start position:0% +these types of things with James was +that a hand up you're gonna give it a + + align:start position:0% +that a hand up you're gonna give it a + + + align:start position:0% +that a hand up you're gonna give it a +shot give it a shot most of these are on + + align:start position:0% +shot give it a shot most of these are on + + + align:start position:0% +shot give it a shot most of these are on +the chain so most of these are off the + + align:start position:0% +the chain so most of these are off the + + + align:start position:0% +the chain so most of these are off the +chain but some is on the chain the idea + + align:start position:0% +chain but some is on the chain the idea + + + align:start position:0% +chain but some is on the chain the idea +is you transact off the chain + + align:start position:0% +is you transact off the chain + + + align:start position:0% +is you transact off the chain +balances are traded in the net results + + align:start position:0% +balances are traded in the net results + + + align:start position:0% +balances are traded in the net results +onto the chain so you try and speed up + + align:start position:0% +onto the chain so you try and speed up + + + align:start position:0% +onto the chain so you try and speed up +by processing off the chain it's like + + align:start position:0% +by processing off the chain it's like + + + align:start position:0% +by processing off the chain it's like +saying there's this chain this this this + + align:start position:0% +saying there's this chain this this this + + + align:start position:0% +saying there's this chain this this this +this this this channel if you wish that + + align:start position:0% +this this this channel if you wish that + + + align:start position:0% +this this this channel if you wish that +the water is running in or the digital + + align:start position:0% +the water is running in or the digital + + + align:start position:0% +the water is running in or the digital +money is running in that only has a + + align:start position:0% +money is running in that only has a + + + align:start position:0% +money is running in that only has a +certain speed it can only take a certain + + align:start position:0% +certain speed it can only take a certain + + + align:start position:0% +certain speed it can only take a certain +amount of performance why not take a lot + + align:start position:0% +amount of performance why not take a lot + + + align:start position:0% +amount of performance why not take a lot +of activity and put it in a side channel + + align:start position:0% +of activity and put it in a side channel + + + align:start position:0% +of activity and put it in a side channel +which is called a payment channel + + align:start position:0% +which is called a payment channel + + + align:start position:0% +which is called a payment channel +actually but a side chain or a payment + + align:start position:0% +actually but a side chain or a payment + + + align:start position:0% +actually but a side chain or a payment +channel or a layer to all with slightly + + align:start position:0% +channel or a layer to all with slightly + + + align:start position:0% +channel or a layer to all with slightly +different technical features and maybe + + align:start position:0% +different technical features and maybe + + + align:start position:0% +different technical features and maybe +do millions of things off here and only + + align:start position:0% +do millions of things off here and only + + + align:start position:0% +do millions of things off here and only +but some here it is not new to + + align:start position:0% +but some here it is not new to + + + align:start position:0% +but some here it is not new to +blockchain and Bitcoin we already have + + align:start position:0% +blockchain and Bitcoin we already have + + + align:start position:0% +blockchain and Bitcoin we already have +that in the world of finance for decades + + align:start position:0% +that in the world of finance for decades + + + align:start position:0% +that in the world of finance for decades +in some way or another where some + + align:start position:0% +in some way or another where some + + + align:start position:0% +in some way or another where some +activity can't go to a central + + align:start position:0% +activity can't go to a central + + + align:start position:0% +activity can't go to a central +settlement system and recalling Ledger's + + align:start position:0% +settlement system and recalling Ledger's + + + align:start position:0% +settlement system and recalling Ledger's +the central bank whether it's the US + + align:start position:0% +the central bank whether it's the US + + + align:start position:0% +the central bank whether it's the US +central bank or any central bank could + + align:start position:0% +central bank or any central bank could + + + align:start position:0% +central bank or any central bank could +have been set up that all of our deposit + + align:start position:0% +have been set up that all of our deposit + + + align:start position:0% +have been set up that all of our deposit +accounts were directly with the central + + align:start position:0% +accounts were directly with the central + + + align:start position:0% +accounts were directly with the central +bank and in a sense the side chains in + + align:start position:0% +bank and in a sense the side chains in + + + align:start position:0% +bank and in a sense the side chains in +finance right now are 9,000 commercial + + align:start position:0% +finance right now are 9,000 commercial + + + align:start position:0% +finance right now are 9,000 commercial +banks 9,000 commercial banks are dealing + + align:start position:0% +banks 9,000 commercial banks are dealing + + + align:start position:0% +banks 9,000 commercial banks are dealing +with our money flows and then sort of + + align:start position:0% +with our money flows and then sort of + + + align:start position:0% +with our money flows and then sort of +net settling to the central bank's + + align:start position:0% +net settling to the central bank's + + + align:start position:0% +net settling to the central bank's +ledger in what's called digital reserves + + align:start position:0% +ledger in what's called digital reserves + + + align:start position:0% +ledger in what's called digital reserves +and in fact even the banking system the + + align:start position:0% +and in fact even the banking system the + + + align:start position:0% +and in fact even the banking system the +9000 banks in the US have their side + + align:start position:0% +9000 banks in the US have their side + + + align:start position:0% +9000 banks in the US have their side +chains Visa MasterCard first data that + + align:start position:0% +chains Visa MasterCard first data that + + + align:start position:0% +chains Visa MasterCard first data that +all the money processing so there's + + align:start position:0% +all the money processing so there's + + + align:start position:0% +all the money processing so there's +already a layering I look at layer two + + align:start position:0% +already a layering I look at layer two + + + align:start position:0% +already a layering I look at layer two +and sidechains + + align:start position:0% +and sidechains + + + align:start position:0% +and sidechains +is kind of taking a similar economic + + align:start position:0% +is kind of taking a similar economic + + + align:start position:0% +is kind of taking a similar economic +approach and technical approach that's + + align:start position:0% +approach and technical approach that's + + + align:start position:0% +approach and technical approach that's +already been around but in a new way I + + align:start position:0% +already been around but in a new way I + + + align:start position:0% +already been around but in a new way I +grabbed a chart from 2015 it the details + + align:start position:0% +grabbed a chart from 2015 it the details + + + align:start position:0% +grabbed a chart from 2015 it the details +don't matter but this was I did it + + align:start position:0% +don't matter but this was I did it + + + align:start position:0% +don't matter but this was I did it +because it was three years old this was + + align:start position:0% +because it was three years old this was + + + align:start position:0% +because it was three years old this was +one you know person's truth coin one + + align:start position:0% +one you know person's truth coin one + + + align:start position:0% +one you know person's truth coin one +person's view is what sidechains + + align:start position:0% +person's view is what sidechains + + + align:start position:0% +person's view is what sidechains +basically what James says lots of + + align:start position:0% +basically what James says lots of + + + align:start position:0% +basically what James says lots of +activity over here and only a few things + + align:start position:0% +activity over here and only a few things + + + align:start position:0% +activity over here and only a few things +go over to the main chain the visual is + + align:start position:0% +go over to the main chain the visual is + + + align:start position:0% +go over to the main chain the visual is +what I wanted to get across it was just + + align:start position:0% +what I wanted to get across it was just + + + align:start position:0% +what I wanted to get across it was just +that it's kind of think of it as loads + + align:start position:0% +that it's kind of think of it as loads + + + align:start position:0% +that it's kind of think of it as loads +of activity over here and then we only + + align:start position:0% +of activity over here and then we only + + + align:start position:0% +of activity over here and then we only +settle at sometimes to the main chain + + align:start position:0% +settle at sometimes to the main chain + + + align:start position:0% +settle at sometimes to the main chain +another visualization of a different is + + align:start position:0% +another visualization of a different is + + + align:start position:0% +another visualization of a different is +the Lightning Network again a lot of + + align:start position:0% +the Lightning Network again a lot of + + + align:start position:0% +the Lightning Network again a lot of +activity then settle to the main chain + + align:start position:0% +activity then settle to the main chain + + + align:start position:0% +activity then settle to the main chain +questions trade off a lot of people are + + align:start position:0% +questions trade off a lot of people are + + + align:start position:0% +questions trade off a lot of people are +proponents of making the block size + + align:start position:0% +proponents of making the block size + + + align:start position:0% +proponents of making the block size +bigger a lot of people say the side + + align:start position:0% +bigger a lot of people say the side + + + align:start position:0% +bigger a lot of people say the side +chains I have trouble understanding + + align:start position:0% +chains I have trouble understanding + + + align:start position:0% +chains I have trouble understanding +trade offs between those two so what + + align:start position:0% +trade offs between those two so what + + + align:start position:0% +trade offs between those two so what +what it like why not just a bigger block + + align:start position:0% +what it like why not just a bigger block + + + align:start position:0% +what it like why not just a bigger block +what's the problem there's a there's a + + align:start position:0% +what's the problem there's a there's a + + + align:start position:0% +what's the problem there's a there's a +series of trade offs of economics and + + align:start position:0% +series of trade offs of economics and + + + align:start position:0% +series of trade offs of economics and +technology the more you put inside the + + align:start position:0% +technology the more you put inside the + + + align:start position:0% +technology the more you put inside the +let's call it the main chain that that + + align:start position:0% +let's call it the main chain that that + + + align:start position:0% +let's call it the main chain that that +blue the blue boxes at the bottom so so + + align:start position:0% +blue the blue boxes at the bottom so so + + + align:start position:0% +blue the blue boxes at the bottom so so +to speak the more you're putting in + + align:start position:0% +to speak the more you're putting in + + + align:start position:0% +to speak the more you're putting in +there you weighed it down there's + + align:start position:0% +there you weighed it down there's + + + align:start position:0% +there you weighed it down there's +there's there's more processing of + + align:start position:0% +there's there's more processing of + + + align:start position:0% +there's there's more processing of +course and more storage and so forth but + + align:start position:0% +course and more storage and so forth but + + + align:start position:0% +course and more storage and so forth but +also there's some there's too much + + align:start position:0% +also there's some there's too much + + + align:start position:0% +also there's some there's too much +latency in Bitcoin it's every 10 minutes + + align:start position:0% +latency in Bitcoin it's every 10 minutes + + + align:start position:0% +latency in Bitcoin it's every 10 minutes +and you're not really sure until three + + align:start position:0% +and you're not really sure until three + + + align:start position:0% +and you're not really sure until three +four or five some would say six blocks + + align:start position:0% +four or five some would say six blocks + + + align:start position:0% +four or five some would say six blocks +to an hour go by so economically if you + + align:start position:0% +to an hour go by so economically if you + + + align:start position:0% +to an hour go by so economically if you +want high frequency low latency short + + align:start position:0% +want high frequency low latency short + + + align:start position:0% +want high frequency low latency short +time periods you might say I can't get + + align:start position:0% +time periods you might say I can't get + + + align:start position:0% +time periods you might say I can't get +that on the main chain because the main + + align:start position:0% +that on the main chain because the main + + + align:start position:0% +that on the main chain because the main +chain wants to have low latency every + + align:start position:0% +chain wants to have low latency every + + + align:start position:0% +chain wants to have low latency every +ten minutes is lower latency now low + + align:start position:0% +ten minutes is lower latency now low + + + align:start position:0% +ten minutes is lower latency now low +latency to be more secure to keep the + + align:start position:0% +latency to be more secure to keep the + + + align:start position:0% +latency to be more secure to keep the +mining cost and the proof-of-work up so + + align:start position:0% +mining cost and the proof-of-work up so + + + align:start position:0% +mining cost and the proof-of-work up so +there's some economic and technological + + align:start position:0% +there's some economic and technological + + + align:start position:0% +there's some economic and technological +both crosscurrents with that unrelated + + align:start position:0% +both crosscurrents with that unrelated + + + align:start position:0% +both crosscurrents with that unrelated +to what I just said but overlapping + + align:start position:0% +to what I just said but overlapping + + + align:start position:0% +to what I just said but overlapping +there's also a bunch of miner and mining + + align:start position:0% +there's also a bunch of miner and mining + + + align:start position:0% +there's also a bunch of miner and mining +pool operator economics as to whether + + align:start position:0% +pool operator economics as to whether + + + align:start position:0% +pool operator economics as to whether +they want big blocks or small blocks and + + align:start position:0% +they want big blocks or small blocks and + + + align:start position:0% +they want big blocks or small blocks and +part of the split last year was but uh + + align:start position:0% +part of the split last year was but uh + + + align:start position:0% +part of the split last year was but uh +it was sort of more motivated around + + align:start position:0% +it was sort of more motivated around + + + align:start position:0% +it was sort of more motivated around +local politics rather than global + + align:start position:0% +local politics rather than global + + + align:start position:0% +local politics rather than global +politics as the former Speaker of the + + align:start position:0% +politics as the former Speaker of the + + + align:start position:0% +politics as the former Speaker of the +House Tip O'Neill said all politics is + + align:start position:0% +House Tip O'Neill said all politics is + + + align:start position:0% +House Tip O'Neill said all politics is +local + + align:start position:0% +local + + + align:start position:0% +local +I think some of the debates last year + + align:start position:0% +I think some of the debates last year + + + align:start position:0% +I think some of the debates last year +was about local economics and the + + align:start position:0% +was about local economics and the + + + align:start position:0% +was about local economics and the +economics of miners but I don't know + + align:start position:0% +economics of miners but I don't know + + + align:start position:0% +economics of miners but I don't know +medoras do you Medora was in probably in + + align:start position:0% +medoras do you Medora was in probably in + + + align:start position:0% +medoras do you Medora was in probably in +the middle of some of those debates but + + align:start position:0% +the middle of some of those debates but + + + align:start position:0% +the middle of some of those debates but +would you have a different view is there + + align:start position:0% +would you have a different view is there + + + align:start position:0% +would you have a different view is there +was a big debate last year as to whether + + align:start position:0% +was a big debate last year as to whether + + + align:start position:0% +was a big debate last year as to whether +the Bitcoin block should go bigger or + + align:start position:0% +the Bitcoin block should go bigger or + + + align:start position:0% +the Bitcoin block should go bigger or +stay the size it was not the only reason + + align:start position:0% +stay the size it was not the only reason + + + align:start position:0% +stay the size it was not the only reason +but it was part of the reason we have + + align:start position:0% +but it was part of the reason we have + + + align:start position:0% +but it was part of the reason we have +now Bitcoin cash and Bitcoin we + + align:start position:0% +now Bitcoin cash and Bitcoin we + + + align:start position:0% +now Bitcoin cash and Bitcoin we +because Bitcoin cash has a bigger block + + align:start position:0% +because Bitcoin cash has a bigger block + + + align:start position:0% +because Bitcoin cash has a bigger block +size and a shorter two and a half minute + + align:start position:0% +size and a shorter two and a half minute + + + align:start position:0% +size and a shorter two and a half minute +processing time mining centralization + + align:start position:0% +processing time mining centralization + + + align:start position:0% +processing time mining centralization +the bigger block Co problem leads of + + align:start position:0% +the bigger block Co problem leads of + + + align:start position:0% +the bigger block Co problem leads of +miners and handles enormous blocks will + + align:start position:0% +miners and handles enormous blocks will + + + align:start position:0% +miners and handles enormous blocks will +be able to stay in business and what + + align:start position:0% +be able to stay in business and what + + + align:start position:0% +be able to stay in business and what +decentralization means was security + + align:start position:0% +decentralization means was security + + + align:start position:0% +decentralization means was security +there's in something for some + + align:start position:0% +there's in something for some + + + align:start position:0% +there's in something for some +decentralization and security to keep + + align:start position:0% +decentralization and security to keep + + + align:start position:0% +decentralization and security to keep +the Box looks smaller + + align:start position:0% +the Box looks smaller + + + align:start position:0% +the Box looks smaller +so what medoras is saying is there's + + align:start position:0% +so what medoras is saying is there's + + + align:start position:0% +so what medoras is saying is there's +also a bit of economics around + + align:start position:0% +also a bit of economics around + + + align:start position:0% +also a bit of economics around +centralization the bigger the blocks the + + align:start position:0% +centralization the bigger the blocks the + + + align:start position:0% +centralization the bigger the blocks the +fewer miners can handle it the fewer + + align:start position:0% +fewer miners can handle it the fewer + + + align:start position:0% +fewer miners can handle it the fewer +miners the more centralization and thus + + align:start position:0% +miners the more centralization and thus + + + align:start position:0% +miners the more centralization and thus +less secure and maybe even economic + + align:start position:0% +less secure and maybe even economic + + + align:start position:0% +less secure and maybe even economic +rents because every centralized system + + align:start position:0% +rents because every centralized system + + + align:start position:0% +rents because every centralized system +can collect economic rents alene that if + + align:start position:0% +can collect economic rents alene that if + + + align:start position:0% +can collect economic rents alene that if +you have bigger blocks they take longer + + align:start position:0% +you have bigger blocks they take longer + + + align:start position:0% +you have bigger blocks they take longer +to propagate to the network and in sort + + align:start position:0% +to propagate to the network and in sort + + + align:start position:0% +to propagate to the network and in sort +of non-intuitive ways if that happens to + + align:start position:0% +of non-intuitive ways if that happens to + + + align:start position:0% +of non-intuitive ways if that happens to +give more accidental Forks in the + + align:start position:0% +give more accidental Forks in the + + + align:start position:0% +give more accidental Forks in the +blockchain and people can accident + + align:start position:0% +blockchain and people can accident + + + align:start position:0% +blockchain and people can accident +before especially Minot State + + align:start position:0% +before especially Minot State + + + align:start position:0% +before especially Minot State +accidentally loose coins when there's a + + align:start position:0% +accidentally loose coins when there's a + + + align:start position:0% +accidentally loose coins when there's a +technical feature as bigger blocks are + + align:start position:0% +technical feature as bigger blocks are + + + align:start position:0% +technical feature as bigger blocks are +more likely to take time to propagate + + align:start position:0% +more likely to take time to propagate + + + align:start position:0% +more likely to take time to propagate +through the network and thus you might + + align:start position:0% +through the network and thus you might + + + align:start position:0% +through the network and thus you might +end up inadvertently having more chains + + align:start position:0% +end up inadvertently having more chains + + + align:start position:0% +end up inadvertently having more chains +that are discredited in a sense because + + align:start position:0% +that are discredited in a sense because + + + align:start position:0% +that are discredited in a sense because +they there there was work being done + + align:start position:0% +they there there was work being done + + + align:start position:0% +they there there was work being done +until the first one gets propagated so + + align:start position:0% +until the first one gets propagated so + + + align:start position:0% +until the first one gets propagated so +Leonar leandro no debt no + + align:start position:0% +Leonar leandro no debt no + + + align:start position:0% +Leonar leandro no debt no +Leandra okay was he asking how do we + + align:start position:0% +Leandra okay was he asking how do we + + + align:start position:0% +Leandra okay was he asking how do we +validate the Lightning Network and how + + align:start position:0% +validate the Lightning Network and how + + + align:start position:0% +validate the Lightning Network and how +do we assure that that is though working + + align:start position:0% +do we assure that that is though working + + + align:start position:0% +do we assure that that is though working +with net to important in the chain how + + align:start position:0% +with net to important in the chain how + + + align:start position:0% +with net to important in the chain how +do we record everything that's ok so the + + align:start position:0% +do we record everything that's ok so the + + + align:start position:0% +do we record everything that's ok so the +side chains are not recorded gross on + + align:start position:0% +side chains are not recorded gross on + + + align:start position:0% +side chains are not recorded gross on +the main chain they're in essence + + align:start position:0% +the main chain they're in essence + + + align:start position:0% +the main chain they're in essence +recorded + + align:start position:0% +recorded + + + align:start position:0% +recorded +and in lightning Network I said I wasn't + + align:start position:0% +and in lightning Network I said I wasn't + + + align:start position:0% +and in lightning Network I said I wasn't +and get into the differences but here I + + align:start position:0% +and get into the differences but here I + + + align:start position:0% +and get into the differences but here I +go the Lightning Network is more a + + align:start position:0% +go the Lightning Network is more a + + + align:start position:0% +go the Lightning Network is more a +bilateral network it can be it can take + + align:start position:0% +bilateral network it can be it can take + + + align:start position:0% +bilateral network it can be it can take +on the the feeling of multilateral + + align:start position:0% +on the the feeling of multilateral + + + align:start position:0% +on the the feeling of multilateral +because I could have a transaction with + + align:start position:0% +because I could have a transaction with + + + align:start position:0% +because I could have a transaction with +James James could have a transaction + + align:start position:0% +James James could have a transaction + + + align:start position:0% +James James could have a transaction +with Kelly and it feels like it's three + + align:start position:0% +with Kelly and it feels like it's three + + + align:start position:0% +with Kelly and it feels like it's three +of us but it's bilateral James and Gary + + align:start position:0% +of us but it's bilateral James and Gary + + + align:start position:0% +of us but it's bilateral James and Gary +bilateral James and Kelly as I + + align:start position:0% +bilateral James and Kelly as I + + + align:start position:0% +bilateral James and Kelly as I +understand it and so those individual + + align:start position:0% +understand it and so those individual + + + align:start position:0% +understand it and so those individual +transactions while they're recorded if + + align:start position:0% +transactions while they're recorded if + + + align:start position:0% +transactions while they're recorded if +keep it going here + + align:start position:0% +keep it going here + + + align:start position:0% +keep it going here +recorded in the Lightning Network + + align:start position:0% +recorded in the Lightning Network + + + align:start position:0% +recorded in the Lightning Network +they're not on the main chain we + + align:start position:0% +they're not on the main chain we + + + align:start position:0% +they're not on the main chain we +ultimately then net settle to the main + + align:start position:0% +ultimately then net settle to the main + + + align:start position:0% +ultimately then net settle to the main +chain and we actually in a sense + + align:start position:0% +chain and we actually in a sense + + + align:start position:0% +chain and we actually in a sense +pre-fund or pre it's a it's a form + + align:start position:0% +pre-fund or pre it's a it's a form + + + align:start position:0% +pre-fund or pre it's a it's a form +loosely of escrowing + + align:start position:0% +loosely of escrowing + + + align:start position:0% +loosely of escrowing +at the beginning so James and I might be + + align:start position:0% +at the beginning so James and I might be + + + align:start position:0% +at the beginning so James and I might be +messing with each other but we're + + align:start position:0% +messing with each other but we're + + + align:start position:0% +messing with each other but we're +bilateral and so we've have another + + align:start position:0% +bilateral and so we've have another + + + align:start position:0% +bilateral and so we've have another +approach to the trust in addition to the + + align:start position:0% +approach to the trust in addition to the + + + align:start position:0% +approach to the trust in addition to the +computer code its James and I might have + + align:start position:0% +computer code its James and I might have + + + align:start position:0% +computer code its James and I might have +other reasons to trust Joe Quinn so and + + align:start position:0% +other reasons to trust Joe Quinn so and + + + align:start position:0% +other reasons to trust Joe Quinn so and +and what keeps me out of double spending + + align:start position:0% +and what keeps me out of double spending + + + align:start position:0% +and what keeps me out of double spending +once on the lady network and another one + + align:start position:0% +once on the lady network and another one + + + align:start position:0% +once on the lady network and another one +on the blockchain main network at the + + align:start position:0% +on the blockchain main network at the + + + align:start position:0% +on the blockchain main network at the +same time because there's a yourself I + + align:start position:0% +same time because there's a yourself I + + + align:start position:0% +same time because there's a yourself I +want to be careful because I'm using the + + align:start position:0% +want to be careful because I'm using the + + + align:start position:0% +want to be careful because I'm using the +terms loosely there's a form of + + align:start position:0% +terms loosely there's a form of + + + align:start position:0% +terms loosely there's a form of +pre-funding it's not that you actually + + align:start position:0% +pre-funding it's not that you actually + + + align:start position:0% +pre-funding it's not that you actually +fund on to the main chain but there's a + + align:start position:0% +fund on to the main chain but there's a + + + align:start position:0% +fund on to the main chain but there's a +little bit of partitioning that Medora + + align:start position:0% +little bit of partitioning that Medora + + + align:start position:0% +little bit of partitioning that Medora +alright I keep looking at Matt doors + + align:start position:0% +alright I keep looking at Matt doors + + + align:start position:0% +alright I keep looking at Matt doors +because he's actually coded this so + + align:start position:0% +because he's actually coded this so + + + align:start position:0% +because he's actually coded this so +that's what protects you in essence that + + align:start position:0% +that's what protects you in essence that + + + align:start position:0% +that's what protects you in essence that +James and I if I'm saying well I'll send + + align:start position:0% +James and I if I'm saying well I'll send + + + align:start position:0% +James and I if I'm saying well I'll send +you a one Bitcoin and tomorrow if the + + align:start position:0% +you a one Bitcoin and tomorrow if the + + + align:start position:0% +you a one Bitcoin and tomorrow if the +Sun does come up tomorrow you'll send me + + align:start position:0% +Sun does come up tomorrow you'll send me + + + align:start position:0% +Sun does come up tomorrow you'll send me +a half we were partitioning that one + + align:start position:0% +a half we were partitioning that one + + + align:start position:0% +a half we were partitioning that one +Bitcoin or his half Bitcoin until we + + align:start position:0% +Bitcoin or his half Bitcoin until we + + + align:start position:0% +Bitcoin or his half Bitcoin until we +then close out that it's written into + + align:start position:0% +then close out that it's written into + + + align:start position:0% +then close out that it's written into +the scripting code and it's written + + align:start position:0% +the scripting code and it's written + + + align:start position:0% +the scripting code and it's written +almost like a smart contract but it's + + align:start position:0% +almost like a smart contract but it's + + + align:start position:0% +almost like a smart contract but it's +not called smart contracts + + align:start position:0% +not called smart contracts + + + align:start position:0% +not called smart contracts +to sort of partition or you might + + align:start position:0% +to sort of partition or you might + + + align:start position:0% +to sort of partition or you might +loosely think of it as escrow it even + + align:start position:0% +loosely think of it as escrow it even + + + align:start position:0% +loosely think of it as escrow it even +though technically it might be different + + align:start position:0% +though technically it might be different + + + align:start position:0% +though technically it might be different +but stop by and we can and if not some + + align:start position:0% +but stop by and we can and if not some + + + align:start position:0% +but stop by and we can and if not some +of our colleagues at the digital + + align:start position:0% +of our colleagues at the digital + + + align:start position:0% +of our colleagues at the digital +currency initiative like Tosh draaga who + + align:start position:0% +currency initiative like Tosh draaga who + + + align:start position:0% +currency initiative like Tosh draaga who +program the Lightning Network I mean + + align:start position:0% +program the Lightning Network I mean + + + align:start position:0% +program the Lightning Network I mean +that's an MIT collaboration with others + + align:start position:0% +that's an MIT collaboration with others + + + align:start position:0% +that's an MIT collaboration with others +and we don't we don't promote it just + + align:start position:0% +and we don't we don't promote it just + + + align:start position:0% +and we don't we don't promote it just +because it's MIT it's like one of the + + align:start position:0% +because it's MIT it's like one of the + + + align:start position:0% +because it's MIT it's like one of the +leading ways to do performance it + + align:start position:0% +leading ways to do performance it + + + align:start position:0% +leading ways to do performance it +happens to be MIT so let me talk about + + align:start position:0% +happens to be MIT so let me talk about + + + align:start position:0% +happens to be MIT so let me talk about +other ways to do performance and kind of + + align:start position:0% +other ways to do performance and kind of + + + align:start position:0% +other ways to do performance and kind of +move on we already talked about + + align:start position:0% +move on we already talked about + + + align:start position:0% +move on we already talked about +alternative consensus protocols + + align:start position:0% +alternative consensus protocols + + + align:start position:0% +alternative consensus protocols +you've seen this slide I'm just bringing + + align:start position:0% +you've seen this slide I'm just bringing + + + align:start position:0% +you've seen this slide I'm just bringing +it back because it is a way to deal with + + align:start position:0% +it back because it is a way to deal with + + + align:start position:0% +it back because it is a way to deal with +scalability it's a really critical + + align:start position:0% +scalability it's a really critical + + + align:start position:0% +scalability it's a really critical +important ways proof-of-work course what + + align:start position:0% +important ways proof-of-work course what + + + align:start position:0% +important ways proof-of-work course what +are the issues about scalability and + + align:start position:0% +are the issues about scalability and + + + align:start position:0% +are the issues about scalability and +generally I'm summarizing I'm + + align:start position:0% +generally I'm summarizing I'm + + + align:start position:0% +generally I'm summarizing I'm +simplifying in a sense but generally all + + align:start position:0% +simplifying in a sense but generally all + + + align:start position:0% +simplifying in a sense but generally all +the alternatives have some way to + + align:start position:0% +the alternatives have some way to + + + align:start position:0% +the alternatives have some way to +randomize or delegate the node that will + + align:start position:0% +randomize or delegate the node that will + + + align:start position:0% +randomize or delegate the node that will +do the next block it kind of all comes + + align:start position:0% +do the next block it kind of all comes + + + align:start position:0% +do the next block it kind of all comes +back how do you add another block and + + align:start position:0% +back how do you add another block and + + + align:start position:0% +back how do you add another block and +Stewart Hebert in the 1990s when he + + align:start position:0% +Stewart Hebert in the 1990s when he + + + align:start position:0% +Stewart Hebert in the 1990s when he +started with all this blockchain stuff + + align:start position:0% +started with all this blockchain stuff + + + align:start position:0% +started with all this blockchain stuff +and put it in the New York Times had a + + align:start position:0% +and put it in the New York Times had a + + + align:start position:0% +and put it in the New York Times had a +central authority and he set up that + + align:start position:0% +central authority and he set up that + + + align:start position:0% +central authority and he set up that +company surety and he put it in the New + + align:start position:0% +company surety and he put it in the New + + + align:start position:0% +company surety and he put it in the New +York Times and what Nakamoto consensus + + align:start position:0% +York Times and what Nakamoto consensus + + + align:start position:0% +York Times and what Nakamoto consensus +is as he said well no we're not going to + + align:start position:0% +is as he said well no we're not going to + + + align:start position:0% +is as he said well no we're not going to +have Hebert and and an essential + + align:start position:0% +have Hebert and and an essential + + + align:start position:0% +have Hebert and and an essential +Authority it's going to be decentralized + + align:start position:0% +Authority it's going to be decentralized + + + align:start position:0% +Authority it's going to be decentralized +so these other consensus protocols + + align:start position:0% +so these other consensus protocols + + + align:start position:0% +so these other consensus protocols +generally have some randomized approach + + align:start position:0% +generally have some randomized approach + + + align:start position:0% +generally have some randomized approach +to delegate the selection of the next + + align:start position:0% +to delegate the selection of the next + + + align:start position:0% +to delegate the selection of the next +block it's not always that way but they + + align:start position:0% +block it's not always that way but they + + + align:start position:0% +block it's not always that way but they +may also have a mechanism to do a second + + align:start position:0% +may also have a mechanism to do a second + + + align:start position:0% +may also have a mechanism to do a second +thing a second touch silvio Macaulay's + + align:start position:0% +thing a second touch silvio Macaulay's + + + align:start position:0% +thing a second touch silvio Macaulay's +Algar and he's a professor over the + + align:start position:0% +Algar and he's a professor over the + + + align:start position:0% +Algar and he's a professor over the +computer science and AI lab and touring + + align:start position:0% +computer science and AI lab and touring + + + align:start position:0% +computer science and AI lab and touring +award-winner he's got a company that has + + align:start position:0% +award-winner he's got a company that has + + + align:start position:0% +award-winner he's got a company that has +an interesting thing it's like a jury + + align:start position:0% +an interesting thing it's like a jury + + + align:start position:0% +an interesting thing it's like a jury +selection it's like picking somebody for + + align:start position:0% +selection it's like picking somebody for + + + align:start position:0% +selection it's like picking somebody for +the jury that's that's picking this + + align:start position:0% +the jury that's that's picking this + + + align:start position:0% +the jury that's that's picking this +short group of 12 nodes that might do + + align:start position:0% +short group of 12 nodes that might do + + + align:start position:0% +short group of 12 nodes that might do +something and every block has that + + align:start position:0% +something and every block has that + + + align:start position:0% +something and every block has that +selection process but then there's an + + align:start position:0% +selection process but then there's an + + + align:start position:0% +selection process but then there's an +another broader group that then can + + align:start position:0% +another broader group that then can + + + align:start position:0% +another broader group that then can +check the work of the jury so often + + align:start position:0% +check the work of the jury so often + + + align:start position:0% +check the work of the jury so often +there's kind of a second automated way + + align:start position:0% +there's kind of a second automated way + + + align:start position:0% +there's kind of a second automated way +because Trust isn't there ensuring that + + align:start position:0% +because Trust isn't there ensuring that + + + align:start position:0% +because Trust isn't there ensuring that +there's a quick second check did they + + align:start position:0% +there's a quick second check did they + + + align:start position:0% +there's a quick second check did they +decide guilty err or innocent correctly + + align:start position:0% +decide guilty err or innocent correctly + + + align:start position:0% +decide guilty err or innocent correctly +so to speak again I apologize if I'm a + + align:start position:0% +so to speak again I apologize if I'm a + + + align:start position:0% +so to speak again I apologize if I'm a +little oversimplifying so vo is + + align:start position:0% +little oversimplifying so vo is + + + align:start position:0% +little oversimplifying so vo is +brilliant work but it's so it could be + + align:start position:0% +brilliant work but it's so it could be + + + align:start position:0% +brilliant work but it's so it could be +proof of stake proof activity proof of + + align:start position:0% +proof of stake proof activity proof of + + + align:start position:0% +proof of stake proof activity proof of +burn as we talked about proof of + + align:start position:0% +burn as we talked about proof of + + + align:start position:0% +burn as we talked about proof of +capacity and as I mentioned last week + + align:start position:0% +capacity and as I mentioned last week + + + align:start position:0% +capacity and as I mentioned last week +there's not large-scale uses but - and + + align:start position:0% +there's not large-scale uses but - and + + + align:start position:0% +there's not large-scale uses but - and +neo both have some form of this going + + align:start position:0% +neo both have some form of this going + + + align:start position:0% +neo both have some form of this going +one right now and aetherium has a big + + align:start position:0% +one right now and aetherium has a big + + + align:start position:0% +one right now and aetherium has a big +project I'm confusing their two projects + + align:start position:0% +project I'm confusing their two projects + + + align:start position:0% +project I'm confusing their two projects +there's plasma and there's Casper Casper + + align:start position:0% +there's plasma and there's Casper Casper + + + align:start position:0% +there's plasma and there's Casper Casper +is their project to get to proof a stake + + align:start position:0% +is their project to get to proof a stake + + + align:start position:0% +is their project to get to proof a stake +but they're not they're privacy and + + align:start position:0% +but they're not they're privacy and + + + align:start position:0% +but they're not they're privacy and +security so try to remember who raised + + align:start position:0% +security so try to remember who raised + + + align:start position:0% +security so try to remember who raised +the contradictory tensions the + + align:start position:0% +the contradictory tensions the + + + align:start position:0% +the contradictory tensions the +contradictory tensions is law + + align:start position:0% +contradictory tensions is law + + + align:start position:0% +contradictory tensions is law +enforcement and regulators want more + + align:start position:0% +enforcement and regulators want more + + + align:start position:0% +enforcement and regulators want more +transparency even though the FBI did you + + align:start position:0% +transparency even though the FBI did you + + + align:start position:0% +transparency even though the FBI did you +know sort of figure out some Russians + + align:start position:0% +know sort of figure out some Russians + + + align:start position:0% +know sort of figure out some Russians +we're using Bitcoin to mess in our + + align:start position:0% +we're using Bitcoin to mess in our + + + align:start position:0% +we're using Bitcoin to mess in our +elections they want some more + + align:start position:0% +elections they want some more + + + align:start position:0% +elections they want some more +transparency and financial institutions + + align:start position:0% +transparency and financial institutions + + + align:start position:0% +transparency and financial institutions +users and even some regulators want less + + align:start position:0% +users and even some regulators want less + + + align:start position:0% +users and even some regulators want less +transparency so it's it's not kind of + + align:start position:0% +transparency so it's it's not kind of + + + align:start position:0% +transparency so it's it's not kind of +goes both ways but these I think are + + align:start position:0% +goes both ways but these I think are + + + align:start position:0% +goes both ways but these I think are +also truly solvable well for for + + align:start position:0% +also truly solvable well for for + + + align:start position:0% +also truly solvable well for for +consumers there's - and Manero and zee + + align:start position:0% +consumers there's - and Manero and zee + + + align:start position:0% +consumers there's - and Manero and zee +cash and there's even mechanisms called + + align:start position:0% +cash and there's even mechanisms called + + + align:start position:0% +cash and there's even mechanisms called +mixing and tumbling which I truthfully + + align:start position:0% +mixing and tumbling which I truthfully + + + align:start position:0% +mixing and tumbling which I truthfully +can't tell you the difference but I can + + align:start position:0% +can't tell you the difference but I can + + + align:start position:0% +can't tell you the difference but I can +tell you regulators talk about mixers + + align:start position:0% +tell you regulators talk about mixers + + + align:start position:0% +tell you regulators talk about mixers +and tumblers and privacy coins when when + + align:start position:0% +and tumblers and privacy coins when when + + + align:start position:0% +and tumblers and privacy coins when when +I go to some regulatory conferences + + align:start position:0% +I go to some regulatory conferences + + + align:start position:0% +I go to some regulatory conferences +because they sometimes invite me as a + + align:start position:0% +because they sometimes invite me as a + + + align:start position:0% +because they sometimes invite me as a +former that middle slide the the privacy + + align:start position:0% +former that middle slide the the privacy + + + align:start position:0% +former that middle slide the the privacy +coins and the mixers and tumblers + + align:start position:0% +coins and the mixers and tumblers + + + align:start position:0% +coins and the mixers and tumblers +the the finance ministries and the + + align:start position:0% +the the finance ministries and the + + + align:start position:0% +the the finance ministries and the +law-enforcement stuff that's where they + + align:start position:0% +law-enforcement stuff that's where they + + + align:start position:0% +law-enforcement stuff that's where they +kind of get worried medoras you want to + + align:start position:0% +kind of get worried medoras you want to + + + align:start position:0% +kind of get worried medoras you want to +come up here and tell us anything about + + align:start position:0% +come up here and tell us anything about + + + align:start position:0% +come up here and tell us anything about +Z cash or you want to do it from there + + align:start position:0% +Z cash or you want to do it from there + + + align:start position:0% +Z cash or you want to do it from there +as to what inspired you to do a privacy + + align:start position:0% +as to what inspired you to do a privacy + + + align:start position:0% +as to what inspired you to do a privacy +coin that a bunch of law enforcement + + align:start position:0% +coin that a bunch of law enforcement + + + align:start position:0% +coin that a bunch of law enforcement +folks don't like it's legal I mean it's + + align:start position:0% +folks don't like it's legal I mean it's + + + align:start position:0% +folks don't like it's legal I mean it's +a coin it's real just like cash can be + + align:start position:0% +a coin it's real just like cash can be + + + align:start position:0% +a coin it's real just like cash can be +used for religious purposes also systems + + align:start position:0% +used for religious purposes also systems + + + align:start position:0% +used for religious purposes also systems +that provide strong privacy like tor can + + align:start position:0% +that provide strong privacy like tor can + + + align:start position:0% +that provide strong privacy like tor can +be used for so it said privacy is a + + align:start position:0% +be used for so it said privacy is a + + + align:start position:0% +be used for so it said privacy is a +human right and we shouldn't be giving + + align:start position:0% +human right and we shouldn't be giving + + + align:start position:0% +human right and we shouldn't be giving +up our fun intro independence too + + align:start position:0% +up our fun intro independence too + + + align:start position:0% +up our fun intro independence too +because I want to buy a coffee I don't + + align:start position:0% +because I want to buy a coffee I don't + + + align:start position:0% +because I want to buy a coffee I don't +want to reveal all my other transactions + + align:start position:0% +want to reveal all my other transactions + + + align:start position:0% +want to reveal all my other transactions +I think there are mechanisms called + + align:start position:0% +I think there are mechanisms called + + + align:start position:0% +I think there are mechanisms called +law enforcement can it gets our + + align:start position:0% +law enforcement can it gets our + + + align:start position:0% +law enforcement can it gets our +regulatory objectives but privacy I + + align:start position:0% +regulatory objectives but privacy I + + + align:start position:0% +regulatory objectives but privacy I +think is fundamental right so we should + + align:start position:0% +think is fundamental right so we should + + + align:start position:0% +think is fundamental right so we should +fight for it and so when did you start + + align:start position:0% +fight for it and so when did you start + + + align:start position:0% +fight for it and so when did you start +working on the project so you started + + align:start position:0% +working on the project so you started + + + align:start position:0% +working on the project so you started +with the paper these kind of like + + align:start position:0% +with the paper these kind of like + + + align:start position:0% +with the paper these kind of like +prototype code base we put it open + + align:start position:0% +prototype code base we put it open + + + align:start position:0% +prototype code base we put it open +source and or with the companies that go + + align:start position:0% +source and or with the companies that go + + + align:start position:0% +source and or with the companies that go +for Monza and I think C cash now is + + align:start position:0% +for Monza and I think C cash now is + + + align:start position:0% +for Monza and I think C cash now is +somewhere around a billion dollar market + + align:start position:0% +somewhere around a billion dollar market + + + align:start position:0% +somewhere around a billion dollar market +cap if so so that's why you're here it + + align:start position:0% +cap if so so that's why you're here it + + + align:start position:0% +cap if so so that's why you're here it +went down no no you don't need to answer + + align:start position:0% +went down no no you don't need to answer + + + align:start position:0% +went down no no you don't need to answer +that that's sorry privacy but but in + + align:start position:0% +that that's sorry privacy but but in + + + align:start position:0% +that that's sorry privacy but but in +essence what medoras is saying that he + + align:start position:0% +essence what medoras is saying that he + + + align:start position:0% +essence what medoras is saying that he +came to this what were you doing in 2014 + + align:start position:0% +came to this what were you doing in 2014 + + + align:start position:0% +came to this what were you doing in 2014 +were you I was mostly working on zero + + align:start position:0% +were you I was mostly working on zero + + + align:start position:0% +were you I was mostly working on zero +knowledge groups seem to be like a + + align:start position:0% +knowledge groups seem to be like a + + + align:start position:0% +knowledge groups seem to be like a +natural application like Bitcoin plus I + + align:start position:0% +natural application like Bitcoin plus I + + + align:start position:0% +natural application like Bitcoin plus I +think I think techniques maybe there's + + align:start position:0% +think I think techniques maybe there's + + + align:start position:0% +think I think techniques maybe there's +something there so here a talented + + align:start position:0% +something there so here a talented + + + align:start position:0% +something there so here a talented +graduate student at MIT with it with the + + align:start position:0% +graduate student at MIT with it with the + + + align:start position:0% +graduate student at MIT with it with the +collaboration of other said here's this + + align:start position:0% +collaboration of other said here's this + + + align:start position:0% +collaboration of other said here's this +cryptographic mechanism called zero + + align:start position:0% +cryptographic mechanism called zero + + + align:start position:0% +cryptographic mechanism called zero +knowledge proof switch we'll chat about + + align:start position:0% +knowledge proof switch we'll chat about + + + align:start position:0% +knowledge proof switch we'll chat about +in 30 seconds and here's something + + align:start position:0% +in 30 seconds and here's something + + + align:start position:0% +in 30 seconds and here's something +called Bitcoin why don't we bring + + align:start position:0% +called Bitcoin why don't we bring + + + align:start position:0% +called Bitcoin why don't we bring +together and we could promote in his own + + align:start position:0% +together and we could promote in his own + + + align:start position:0% +together and we could promote in his own +words some human rights just did you buy + + align:start position:0% +words some human rights just did you buy + + + align:start position:0% +words some human rights just did you buy +a cup of coffee and you don't have to + + align:start position:0% +a cup of coffee and you don't have to + + + align:start position:0% +a cup of coffee and you don't have to +say who you are you could use this new + + align:start position:0% +say who you are you could use this new + + + align:start position:0% +say who you are you could use this new +Bitcoin and enhanced zero knowledge + + align:start position:0% +Bitcoin and enhanced zero knowledge + + + align:start position:0% +Bitcoin and enhanced zero knowledge +proof Z cash shot if I useful to one + + align:start position:0% +proof Z cash shot if I useful to one + + + align:start position:0% +proof Z cash shot if I useful to one +arrow or three cash as a way to get the + + align:start position:0% +arrow or three cash as a way to get the + + + align:start position:0% +arrow or three cash as a way to get the +money out of that I don't I don't + + align:start position:0% +money out of that I don't I don't + + + align:start position:0% +money out of that I don't I don't +fortunately I don't have to define + + align:start position:0% +fortunately I don't have to define + + + align:start position:0% +fortunately I don't have to define +illicit activity but generally societies + + align:start position:0% +illicit activity but generally societies + + + align:start position:0% +illicit activity but generally societies +come together through their reasonable + + align:start position:0% +come together through their reasonable + + + align:start position:0% +come together through their reasonable +mechanisms whether they're democratic + + align:start position:0% +mechanisms whether they're democratic + + + align:start position:0% +mechanisms whether they're democratic +societies or not but they come together + + align:start position:0% +societies or not but they come together + + + align:start position:0% +societies or not but they come together +through their legislative branches and + + align:start position:0% +through their legislative branches and + + + align:start position:0% +through their legislative branches and +their executive branches and their + + align:start position:0% +their executive branches and their + + + align:start position:0% +their executive branches and their +courts and define some things that are + + align:start position:0% +courts and define some things that are + + + align:start position:0% +courts and define some things that are +not allowed but generally speaking when + + align:start position:0% +not allowed but generally speaking when + + + align:start position:0% +not allowed but generally speaking when +I'm using the term in this class I'm + + align:start position:0% +I'm using the term in this class I'm + + + align:start position:0% +I'm using the term in this class I'm +thinking about four or five buckets most + + align:start position:0% +thinking about four or five buckets most + + + align:start position:0% +thinking about four or five buckets most +societies do not want to shrink their + + align:start position:0% +societies do not want to shrink their + + + align:start position:0% +societies do not want to shrink their +tax base so they want economic activity + + align:start position:0% +tax base so they want economic activity + + + align:start position:0% +tax base so they want economic activity +be inside the tax envelope rather than + + align:start position:0% +be inside the tax envelope rather than + + + align:start position:0% +be inside the tax envelope rather than +outside the tax envelope and that's + + align:start position:0% +outside the tax envelope and that's + + + align:start position:0% +outside the tax envelope and that's +usually the words that finance ministers + + align:start position:0% +usually the words that finance ministers + + + align:start position:0% +usually the words that finance ministers +call that as a tax base how much is + + align:start position:0% +call that as a tax base how much is + + + align:start position:0% +call that as a tax base how much is +outside versus inside secondly most law + + align:start position:0% +outside versus inside secondly most law + + + align:start position:0% +outside versus inside secondly most law +enforcement and most societies do not + + align:start position:0% +enforcement and most societies do not + + + align:start position:0% +enforcement and most societies do not +want to have the the money rails the + + align:start position:0% +want to have the the money rails the + + + align:start position:0% +want to have the the money rails the +banking and other ways you can move + + align:start position:0% +banking and other ways you can move + + + align:start position:0% +banking and other ways you can move +value to facilitate otherwise illegal + + align:start position:0% +value to facilitate otherwise illegal + + + align:start position:0% +value to facilitate otherwise illegal +activity so it's using money to + + align:start position:0% +activity so it's using money to + + + align:start position:0% +activity so it's using money to +facilitate otherwise illegal activity so + + align:start position:0% +facilitate otherwise illegal activity so + + + align:start position:0% +facilitate otherwise illegal activity so +the otherwise illegal activity might be + + align:start position:0% +the otherwise illegal activity might be + + + align:start position:0% +the otherwise illegal activity might be +drug running the otherwise illegal + + align:start position:0% +drug running the otherwise illegal + + + align:start position:0% +drug running the otherwise illegal +activity might be terrorism it might be + + align:start position:0% +activity might be terrorism it might be + + + align:start position:0% +activity might be terrorism it might be +child slavery literally so it's whatever + + align:start position:0% +child slavery literally so it's whatever + + + align:start position:0% +child slavery literally so it's whatever +the otherwise illegal activity you know + + align:start position:0% +the otherwise illegal activity you know + + + align:start position:0% +the otherwise illegal activity you know +is to use money and that's generally + + align:start position:0% +is to use money and that's generally + + + align:start position:0% +is to use money and that's generally +called money laundering or other things + + align:start position:0% +called money laundering or other things + + + align:start position:0% +called money laundering or other things +so you're absolutely right another thing + + align:start position:0% +so you're absolutely right another thing + + + align:start position:0% +so you're absolutely right another thing +is for + + align:start position:0% +is for + + + align:start position:0% +is for +some countries less than a majority but + + align:start position:0% +some countries less than a majority but + + + align:start position:0% +some countries less than a majority but +some countries have capital controls + + align:start position:0% +some countries have capital controls + + + align:start position:0% +some countries have capital controls +they're trying to maintain the value of + + align:start position:0% +they're trying to maintain the value of + + + align:start position:0% +they're trying to maintain the value of +their fiat currency relative to other + + align:start position:0% +their fiat currency relative to other + + + align:start position:0% +their fiat currency relative to other +fiat currencies and in an effort to + + align:start position:0% +fiat currencies and in an effort to + + + align:start position:0% +fiat currencies and in an effort to +maintain some either fixed or + + align:start position:0% +maintain some either fixed or + + + align:start position:0% +maintain some either fixed or +relationship they have capital controls + + align:start position:0% +relationship they have capital controls + + + align:start position:0% +relationship they have capital controls +and and thus in those countries they + + align:start position:0% +and and thus in those countries they + + + align:start position:0% +and and thus in those countries they +might say illicit activity also is + + align:start position:0% +might say illicit activity also is + + + align:start position:0% +might say illicit activity also is +running around the the capital controls + + align:start position:0% +running around the the capital controls + + + align:start position:0% +running around the the capital controls +but it's it's each country each society + + align:start position:0% +but it's it's each country each society + + + align:start position:0% +but it's it's each country each society +and Shawn you raise a good point as to + + align:start position:0% +and Shawn you raise a good point as to + + + align:start position:0% +and Shawn you raise a good point as to +what does it mean I I I mean it not to + + align:start position:0% +what does it mean I I I mean it not to + + + align:start position:0% +what does it mean I I I mean it not to +show any value I'm saying there's a + + align:start position:0% +show any value I'm saying there's a + + + align:start position:0% +show any value I'm saying there's a +there's a series of these things that + + align:start position:0% +there's a series of these things that + + + align:start position:0% +there's a series of these things that +each society comes together and says + + align:start position:0% +each society comes together and says + + + align:start position:0% +each society comes together and says +usually around the tax base usually + + align:start position:0% +usually around the tax base usually + + + align:start position:0% +usually around the tax base usually +around trying to not use money to + + align:start position:0% +around trying to not use money to + + + align:start position:0% +around trying to not use money to +facilitate otherwise bad stuff and in + + align:start position:0% +facilitate otherwise bad stuff and in + + + align:start position:0% +facilitate otherwise bad stuff and in +some countries the capital controls I + + align:start position:0% +some countries the capital controls I + + + align:start position:0% +some countries the capital controls I +saw a hand here Daniel no wizard and + + align:start position:0% +saw a hand here Daniel no wizard and + + + align:start position:0% +saw a hand here Daniel no wizard and +we're gonna do more about illicit + + align:start position:0% +we're gonna do more about illicit + + + align:start position:0% +we're gonna do more about illicit +activity next week or about guarding + + align:start position:0% +activity next week or about guarding + + + align:start position:0% +activity next week or about guarding +against illicit activity I hope the + + align:start position:0% +against illicit activity I hope the + + + align:start position:0% +against illicit activity I hope the +correction got film too so there's + + align:start position:0% +correction got film too so there's + + + align:start position:0% +correction got film too so there's +another set of security issues around + + align:start position:0% +another set of security issues around + + + align:start position:0% +another set of security issues around +private keys and to most of us that have + + align:start position:0% +private keys and to most of us that have + + + align:start position:0% +private keys and to most of us that have +passwords you know if you lose your + + align:start position:0% +passwords you know if you lose your + + + align:start position:0% +passwords you know if you lose your +password they're usually in essence a + + align:start position:0% +password they're usually in essence a + + + align:start position:0% +password they're usually in essence a +backdoor that somehow the the platform + + align:start position:0% +backdoor that somehow the the platform + + + align:start position:0% +backdoor that somehow the the platform +whether it's Facebook or even at Bank of + + align:start position:0% +whether it's Facebook or even at Bank of + + + align:start position:0% +whether it's Facebook or even at Bank of +America if you lose your password + + align:start position:0% +America if you lose your password + + + align:start position:0% +America if you lose your password +there's a backdoor and they can say + + align:start position:0% +there's a backdoor and they can say + + + align:start position:0% +there's a backdoor and they can say +there's a way to validate with enough + + align:start position:0% +there's a way to validate with enough + + + align:start position:0% +there's a way to validate with enough +probability waiting that I'm Gary + + align:start position:0% +probability waiting that I'm Gary + + + align:start position:0% +probability waiting that I'm Gary +Gensler and they'll give me a new + + align:start position:0% +Gensler and they'll give me a new + + + align:start position:0% +Gensler and they'll give me a new +password I mean in some circumstances + + align:start position:0% +password I mean in some circumstances + + + align:start position:0% +password I mean in some circumstances +it's a high bar and there's some + + align:start position:0% +it's a high bar and there's some + + + align:start position:0% +it's a high bar and there's some +biometrics involved but in most cases + + align:start position:0% +biometrics involved but in most cases + + + align:start position:0% +biometrics involved but in most cases +it's a pretty low bar and they'll give + + align:start position:0% +it's a pretty low bar and they'll give + + + align:start position:0% +it's a pretty low bar and they'll give +you sort of another password if you can + + align:start position:0% +you sort of another password if you can + + + align:start position:0% +you sort of another password if you can +like me remember the answer to who my + + align:start position:0% +like me remember the answer to who my + + + align:start position:0% +like me remember the answer to who my +high school girlfriend was or something + + align:start position:0% +high school girlfriend was or something + + + align:start position:0% +high school girlfriend was or something +you know these questions like I remember + + align:start position:0% +you know these questions like I remember + + + align:start position:0% +you know these questions like I remember +it's Irene but then I've just given up + + align:start position:0% +it's Irene but then I've just given up + + + align:start position:0% +it's Irene but then I've just given up +I'm just giving it up that's terrible + + align:start position:0% +I'm just giving it up that's terrible + + + align:start position:0% +I'm just giving it up that's terrible +I have to change it so but custodial of + + align:start position:0% +I have to change it so but custodial of + + + align:start position:0% +I have to change it so but custodial of +private keys is a very real thing and + + align:start position:0% +private keys is a very real thing and + + + align:start position:0% +private keys is a very real thing and +you've read about the hacking and will + + align:start position:0% +you've read about the hacking and will + + + align:start position:0% +you've read about the hacking and will +read more about it when we get to crypto + + align:start position:0% +read more about it when we get to crypto + + + align:start position:0% +read more about it when we get to crypto +exchanges it's it's a very dominant + + align:start position:0% +exchanges it's it's a very dominant + + + align:start position:0% +exchanges it's it's a very dominant +issue not just for individuals but for + + align:start position:0% +issue not just for individuals but for + + + align:start position:0% +issue not just for individuals but for +institutional actors how does a hedge + + align:start position:0% +institutional actors how does a hedge + + + align:start position:0% +institutional actors how does a hedge +fund or more likely how does Blackrock + + align:start position:0% +fund or more likely how does Blackrock + + + align:start position:0% +fund or more likely how does Blackrock +or fidelity as an asset manager secure + + align:start position:0% +or fidelity as an asset manager secure + + + align:start position:0% +or fidelity as an asset manager secure +custody in a way that works and it's an + + align:start position:0% +custody in a way that works and it's an + + + align:start position:0% +custody in a way that works and it's an +asymmetric risk it's a tricky risk for + + align:start position:0% +asymmetric risk it's a tricky risk for + + + align:start position:0% +asymmetric risk it's a tricky risk for +most of finance they don't have custody + + align:start position:0% +most of finance they don't have custody + + + align:start position:0% +most of finance they don't have custody +any longer of the securities when I + + align:start position:0% +any longer of the securities when I + + + align:start position:0% +any longer of the securities when I +started a wall street they were still + + align:start position:0% +started a wall street they were still + + + align:start position:0% +started a wall street they were still +the cage CAG II there was a physical + + align:start position:0% +the cage CAG II there was a physical + + + align:start position:0% +the cage CAG II there was a physical +cage where the the remnants of paper + + align:start position:0% +cage where the the remnants of paper + + + align:start position:0% +cage where the the remnants of paper +stock certificates were still in the + + align:start position:0% +stock certificates were still in the + + + align:start position:0% +stock certificates were still in the +cage + + align:start position:0% +cage + + + align:start position:0% +cage +I didn't start so long ago that it was + + align:start position:0% +I didn't start so long ago that it was + + + align:start position:0% +I didn't start so long ago that it was +before DTCC was already things were + + align:start position:0% +before DTCC was already things were + + + align:start position:0% +before DTCC was already things were +getting electric you know digital but + + align:start position:0% +getting electric you know digital but + + + align:start position:0% +getting electric you know digital but +there was still a physical cage for some + + align:start position:0% +there was still a physical cage for some + + + align:start position:0% +there was still a physical cage for some +physical paper certificates if you lost + + align:start position:0% +physical paper certificates if you lost + + + align:start position:0% +physical paper certificates if you lost +the paper certificate you could still go + + align:start position:0% +the paper certificate you could still go + + + align:start position:0% +the paper certificate you could still go +to the government or the company that + + align:start position:0% +to the government or the company that + + + align:start position:0% +to the government or the company that +issued it and back door and get a new + + align:start position:0% +issued it and back door and get a new + + + align:start position:0% +issued it and back door and get a new +paper certificate + + align:start position:0% +paper certificate + + + align:start position:0% +paper certificate +it took time it was hard it was to + + align:start position:0% +it took time it was hard it was to + + + align:start position:0% +it took time it was hard it was to +authenticated but in this circumstance + + align:start position:0% +authenticated but in this circumstance + + + align:start position:0% +authenticated but in this circumstance +if you lose the private key there's not + + align:start position:0% +if you lose the private key there's not + + + align:start position:0% +if you lose the private key there's not +the back door issue or to get the next + + align:start position:0% +the back door issue or to get the next + + + align:start position:0% +the back door issue or to get the next +one so it's a very interesting issue not + + align:start position:0% +one so it's a very interesting issue not + + + align:start position:0% +one so it's a very interesting issue not +just a technological issue but in a + + align:start position:0% +just a technological issue but in a + + + align:start position:0% +just a technological issue but in a +cyber security issue but it's a whole + + align:start position:0% +cyber security issue but it's a whole + + + align:start position:0% +cyber security issue but it's a whole +set of financial custody issues an + + align:start position:0% +set of financial custody issues an + + + align:start position:0% +set of financial custody issues an +asymmetric risk if you're Goldman Sachs + + align:start position:0% +asymmetric risk if you're Goldman Sachs + + + align:start position:0% +asymmetric risk if you're Goldman Sachs +or fidelity and you lost a key or it got + + align:start position:0% +or fidelity and you lost a key or it got + + + align:start position:0% +or fidelity and you lost a key or it got +hacked and it was billions of dollars so + + align:start position:0% +hacked and it was billions of dollars so + + + align:start position:0% +hacked and it was billions of dollars so +it's just a interesting I don't think + + align:start position:0% +it's just a interesting I don't think + + + align:start position:0% +it's just a interesting I don't think +it's unique to blockchain but it's + + align:start position:0% +it's unique to blockchain but it's + + + align:start position:0% +it's unique to blockchain but it's +rather specific to blockchain and + + align:start position:0% +rather specific to blockchain and + + + align:start position:0% +rather specific to blockchain and +finance and how it overlaps it so some + + align:start position:0% +finance and how it overlaps it so some + + + align:start position:0% +finance and how it overlaps it so some +of the solutions that I do think there + + align:start position:0% +of the solutions that I do think there + + + align:start position:0% +of the solutions that I do think there +are solutions here are some of the + + align:start position:0% +are solutions here are some of the + + + align:start position:0% +are solutions here are some of the +things that that medoras and Nahan + + align:start position:0% +things that that medoras and Nahan + + + align:start position:0% +things that that medoras and Nahan +Narula who runs the digital currency + + align:start position:0% +Narula who runs the digital currency + + + align:start position:0% +Narula who runs the digital currency +initiative or work + + align:start position:0% +initiative or work + + + align:start position:0% +initiative or work +and they're working on using two + + align:start position:0% +and they're working on using two + + + align:start position:0% +and they're working on using two +cryptographic primitives we're not going + + align:start position:0% +cryptographic primitives we're not going + + + align:start position:0% +cryptographic primitives we're not going +to deeply go into we did hash functions + + align:start position:0% +to deeply go into we did hash functions + + + align:start position:0% +to deeply go into we did hash functions +and we did digital signatures those are + + align:start position:0% +and we did digital signatures those are + + + align:start position:0% +and we did digital signatures those are +algorithms or they're called + + align:start position:0% +algorithms or they're called + + + align:start position:0% +algorithms or they're called +cryptographic primitives + + align:start position:0% +cryptographic primitives + + + align:start position:0% +cryptographic primitives +well there's dozens cryptographic + + align:start position:0% +well there's dozens cryptographic + + + align:start position:0% +well there's dozens cryptographic +primitives math algorithms well the + + align:start position:0% +primitives math algorithms well the + + + align:start position:0% +primitives math algorithms well the +other two that are used a lot in this + + align:start position:0% +other two that are used a lot in this + + + align:start position:0% +other two that are used a lot in this +field or zero knowledge proof and less + + align:start position:0% +field or zero knowledge proof and less + + + align:start position:0% +field or zero knowledge proof and less +often probably as Peterson commitments + + align:start position:0% +often probably as Peterson commitments + + + align:start position:0% +often probably as Peterson commitments +and I put up there my words + + align:start position:0% +and I put up there my words + + + align:start position:0% +and I put up there my words +I got medoras to help me write this one + + align:start position:0% +I got medoras to help me write this one + + + align:start position:0% +I got medoras to help me write this one +but my words is zero knowledge proof + + align:start position:0% +but my words is zero knowledge proof + + + align:start position:0% +but my words is zero knowledge proof +let's someone prove a statement is true + + align:start position:0% +let's someone prove a statement is true + + + align:start position:0% +let's someone prove a statement is true +without revealing the details of exactly + + align:start position:0% +without revealing the details of exactly + + + align:start position:0% +without revealing the details of exactly +why that statement is true you might say + + align:start position:0% +why that statement is true you might say + + + align:start position:0% +why that statement is true you might say +wait a minute you can prove something's + + align:start position:0% +wait a minute you can prove something's + + + align:start position:0% +wait a minute you can prove something's +true it's sort of like if you walk into + + align:start position:0% +true it's sort of like if you walk into + + + align:start position:0% +true it's sort of like if you walk into +a bar and they need to know you're 21 to + + align:start position:0% +a bar and they need to know you're 21 to + + + align:start position:0% +a bar and they need to know you're 21 to +get a drink let's make this tangible + + align:start position:0% +get a drink let's make this tangible + + + align:start position:0% +get a drink let's make this tangible +what do you need to prove that you're 21 + + align:start position:0% +what do you need to prove that you're 21 + + + align:start position:0% +what do you need to prove that you're 21 +you need to prove that you were born + + align:start position:0% +you need to prove that you were born + + + align:start position:0% +you need to prove that you were born +before 1997 September 27th but you don't + + align:start position:0% +before 1997 September 27th but you don't + + + align:start position:0% +before 1997 September 27th but you don't +need a lot more details and so there's + + align:start position:0% +need a lot more details and so there's + + + align:start position:0% +need a lot more details and so there's +some computer scientists here at MIT + + align:start position:0% +some computer scientists here at MIT + + + align:start position:0% +some computer scientists here at MIT +that actually did the foundational work + + align:start position:0% +that actually did the foundational work + + + align:start position:0% +that actually did the foundational work +when zero knowledge proves 20 to 30 + + align:start position:0% +when zero knowledge proves 20 to 30 + + + align:start position:0% +when zero knowledge proves 20 to 30 +years ago Silvio McCauley and others for + + align:start position:0% +years ago Silvio McCauley and others for + + + align:start position:0% +years ago Silvio McCauley and others for +which I think was part of why they won + + align:start position:0% +which I think was part of why they won + + + align:start position:0% +which I think was part of why they won +the Turing award and amongst other work + + align:start position:0% +the Turing award and amongst other work + + + align:start position:0% +the Turing award and amongst other work +so zero knowledge proof sir very + + align:start position:0% +so zero knowledge proof sir very + + + align:start position:0% +so zero knowledge proof sir very +interesting cryptographic mathematical + + align:start position:0% +interesting cryptographic mathematical + + + align:start position:0% +interesting cryptographic mathematical +puzzle solving that medoras used for z + + align:start position:0% +puzzle solving that medoras used for z + + + align:start position:0% +puzzle solving that medoras used for z +cache nahama doris is using for + + align:start position:0% +cache nahama doris is using for + + + align:start position:0% +cache nahama doris is using for +something called ZK ledger which was an + + align:start position:0% +something called ZK ledger which was an + + + align:start position:0% +something called ZK ledger which was an +optional reading my gut tells me there + + align:start position:0% +optional reading my gut tells me there + + + align:start position:0% +optional reading my gut tells me there +are ways that we can go forward that + + align:start position:0% +are ways that we can go forward that + + + align:start position:0% +are ways that we can go forward that +regulators and the official sector can + + align:start position:0% +regulators and the official sector can + + + align:start position:0% +regulators and the official sector can +get there transparency they want and the + + align:start position:0% +get there transparency they want and the + + + align:start position:0% +get there transparency they want and the +financial sector at the same time can + + align:start position:0% +financial sector at the same time can + + + align:start position:0% +financial sector at the same time can +get the privacy they want that the two + + align:start position:0% +get the privacy they want that the two + + + align:start position:0% +get the privacy they want that the two +can actually coexist through the modern + + align:start position:0% +can actually coexist through the modern + + + align:start position:0% +can actually coexist through the modern +methods of technology Alexi is that a + + align:start position:0% +methods of technology Alexi is that a + + + align:start position:0% +methods of technology Alexi is that a +hand up or just waving no all right you + + align:start position:0% +hand up or just waving no all right you + + + align:start position:0% +hand up or just waving no all right you +want to add anything Medora since your + + align:start position:0% +want to add anything Medora since your + + + align:start position:0% +want to add anything Medora since your +the co-author of this ZK ledger paper + + align:start position:0% +the co-author of this ZK ledger paper + + + align:start position:0% +the co-author of this ZK ledger paper +that was optional + + align:start position:0% + + + + align:start position:0% + +coin zero coy using Peterson clearance + + align:start position:0% +coin zero coy using Peterson clearance + + + align:start position:0% +coin zero coy using Peterson clearance +on Z cash + + align:start position:0% +on Z cash + + + align:start position:0% +on Z cash +bidding tears Peters and commitments + + align:start position:0% +bidding tears Peters and commitments + + + align:start position:0% +bidding tears Peters and commitments +like small talk very interesting history + + align:start position:0% +like small talk very interesting history + + + align:start position:0% +like small talk very interesting history +behind and Peterson commitments are yet + + align:start position:0% +behind and Peterson commitments are yet + + + align:start position:0% +behind and Peterson commitments are yet +another cryptographic primitive or + + align:start position:0% +another cryptographic primitive or + + + align:start position:0% +another cryptographic primitive or +algorithm which interestingly they're + + align:start position:0% +algorithm which interestingly they're + + + align:start position:0% +algorithm which interestingly they're +similar to hash functions where you take + + align:start position:0% +similar to hash functions where you take + + + align:start position:0% +similar to hash functions where you take +a bunch of data and you squish it + + align:start position:0% +a bunch of data and you squish it + + + align:start position:0% +a bunch of data and you squish it +together in a sense you compress it and + + align:start position:0% +together in a sense you compress it and + + + align:start position:0% +together in a sense you compress it and +get a commitment but you can actually + + align:start position:0% +get a commitment but you can actually + + + align:start position:0% +get a commitment but you can actually +add and subtract them it's it's an + + align:start position:0% +add and subtract them it's it's an + + + align:start position:0% +add and subtract them it's it's an +interesting thing where you can commit + + align:start position:0% +interesting thing where you can commit + + + align:start position:0% +interesting thing where you can commit +today to like a hash but you can also + + align:start position:0% +today to like a hash but you can also + + + align:start position:0% +today to like a hash but you can also +add and and and sort of subtract + + align:start position:0% +add and and and sort of subtract + + + align:start position:0% +add and and and sort of subtract +commitments so it has some interesting + + align:start position:0% +commitments so it has some interesting + + + align:start position:0% +commitments so it has some interesting +features if you're deeply interested I + + align:start position:0% +features if you're deeply interested I + + + align:start position:0% +features if you're deeply interested I +will probably line up Sabrina to help + + align:start position:0% +will probably line up Sabrina to help + + + align:start position:0% +will probably line up Sabrina to help +you or medoras might help because I'm at + + align:start position:0% +you or medoras might help because I'm at + + + align:start position:0% +you or medoras might help because I'm at +the edge but what I'm saying from a + + align:start position:0% +the edge but what I'm saying from a + + + align:start position:0% +the edge but what I'm saying from a +business side is my hunch and this is + + align:start position:0% +business side is my hunch and this is + + + align:start position:0% +business side is my hunch and this is +that we're at the we're at the cutting + + align:start position:0% +that we're at the we're at the cutting + + + align:start position:0% +that we're at the we're at the cutting +edge here at MIT of some of the folks + + align:start position:0% +edge here at MIT of some of the folks + + + align:start position:0% +edge here at MIT of some of the folks +try to figure out how to do privacy and + + align:start position:0% +try to figure out how to do privacy and + + + align:start position:0% +try to figure out how to do privacy and +security at the same time questions on + + align:start position:0% +security at the same time questions on + + + align:start position:0% +security at the same time questions on +that because we're gonna get to the + + align:start position:0% +that because we're gonna get to the + + + align:start position:0% +that because we're gonna get to the +tougher things interoperability linking + + align:start position:0% +tougher things interoperability linking + + + align:start position:0% +tougher things interoperability linking +blockchain applications to legacy + + align:start position:0% +blockchain applications to legacy + + + align:start position:0% +blockchain applications to legacy +databases or linking them to each other + + align:start position:0% +databases or linking them to each other + + + align:start position:0% +databases or linking them to each other +so you might want to link a blockchain + + align:start position:0% +so you might want to link a blockchain + + + align:start position:0% +so you might want to link a blockchain +application if you're if you're thinking + + align:start position:0% +application if you're if you're thinking + + + align:start position:0% +application if you're if you're thinking +about a payments protocol how does that + + align:start position:0% +about a payments protocol how does that + + + align:start position:0% +about a payments protocol how does that +payments protocol and blockchain world + + align:start position:0% +payments protocol and blockchain world + + + align:start position:0% +payments protocol and blockchain world +link to the Fiat because ultimately if + + align:start position:0% +link to the Fiat because ultimately if + + + align:start position:0% +link to the Fiat because ultimately if +you're doing let's say remittances and + + align:start position:0% +you're doing let's say remittances and + + + align:start position:0% +you're doing let's say remittances and +you want to move money from here to + + align:start position:0% +you want to move money from here to + + + align:start position:0% +you want to move money from here to +Mexico + + align:start position:0% +Mexico + + + align:start position:0% +Mexico +somebody wants Mexican peso they might + + align:start position:0% +somebody wants Mexican peso they might + + + align:start position:0% +somebody wants Mexican peso they might +be starting in US dollars how do you how + + align:start position:0% +be starting in US dollars how do you how + + + align:start position:0% +be starting in US dollars how do you how +do you operate basically with three + + align:start position:0% +do you operate basically with three + + + align:start position:0% +do you operate basically with three +different systems in that case you know + + align:start position:0% +different systems in that case you know + + + align:start position:0% +different systems in that case you know +you're ingenious innovative startup but + + align:start position:0% +you're ingenious innovative startup but + + + align:start position:0% +you're ingenious innovative startup but +the US dollar Fiats system and the + + align:start position:0% +the US dollar Fiats system and the + + + align:start position:0% +the US dollar Fiats system and the +Mexican peso system so that's a form of + + align:start position:0% +Mexican peso system so that's a form of + + + align:start position:0% +Mexican peso system so that's a form of +interoperability and and the challenge + + align:start position:0% +interoperability and and the challenge + + + align:start position:0% +interoperability and and the challenge +around it or blockchain to blockchain if + + align:start position:0% +around it or blockchain to blockchain if + + + align:start position:0% +around it or blockchain to blockchain if +we've got sixteen hundred of them or + + align:start position:0% +we've got sixteen hundred of them or + + + align:start position:0% +we've got sixteen hundred of them or +even interoperability of the main chain + + align:start position:0% +even interoperability of the main chain + + + align:start position:0% +even interoperability of the main chain +and some of these layer to inside shades + + align:start position:0% +and some of these layer to inside shades + + + align:start position:0% +and some of these layer to inside shades +that's an easier + + align:start position:0% +that's an easier + + + align:start position:0% +that's an easier +interoperability because it's kind of + + align:start position:0% +interoperability because it's kind of + + + align:start position:0% +interoperability because it's kind of +coded right in but it's always it and + + align:start position:0% +coded right in but it's always it and + + + align:start position:0% +coded right in but it's always it and +this is not a new thing banking has had + + align:start position:0% +this is not a new thing banking has had + + + align:start position:0% +this is not a new thing banking has had +interoperability all the time take my + + align:start position:0% +interoperability all the time take my + + + align:start position:0% +interoperability all the time take my +example of the u.s. to Mexico to move US + + align:start position:0% +example of the u.s. to Mexico to move US + + + align:start position:0% +example of the u.s. to Mexico to move US +Dollars and convert it to Mexican peso + + align:start position:0% +Dollars and convert it to Mexican peso + + + align:start position:0% +Dollars and convert it to Mexican peso +is in two entirely different banking + + align:start position:0% +is in two entirely different banking + + + align:start position:0% +is in two entirely different banking +systems in two entirely different ledger + + align:start position:0% +systems in two entirely different ledger + + + align:start position:0% +systems in two entirely different ledger +systems so we have to have this question + + align:start position:0% +systems so we have to have this question + + + align:start position:0% +systems so we have to have this question +of interoperability even pre blockchain + + align:start position:0% +of interoperability even pre blockchain + + + align:start position:0% +of interoperability even pre blockchain +but it's just bringing it to this new + + align:start position:0% +but it's just bringing it to this new + + + align:start position:0% +but it's just bringing it to this new +technology + + align:start position:0% +technology + + + align:start position:0% +technology +it raises cost of trust in coordinating + + align:start position:0% +it raises cost of trust in coordinating + + + align:start position:0% +it raises cost of trust in coordinating +the transfer assets and information + + align:start position:0% +the transfer assets and information + + + align:start position:0% +the transfer assets and information +across chains in essence or as we talked + + align:start position:0% +across chains in essence or as we talked + + + align:start position:0% +across chains in essence or as we talked +about across Ledger's so it's a it's an + + align:start position:0% +about across Ledger's so it's a it's an + + + align:start position:0% +about across Ledger's so it's a it's an +issue that's it's been around we just + + align:start position:0% +issue that's it's been around we just + + + align:start position:0% +issue that's it's been around we just +got to sort of see how we solve it here + + align:start position:0% +got to sort of see how we solve it here + + + align:start position:0% +got to sort of see how we solve it here +one solution it doesn't mean it's the + + align:start position:0% +one solution it doesn't mean it's the + + + align:start position:0% +one solution it doesn't mean it's the +right solution is the only solution well + + align:start position:0% +right solution is the only solution well + + + align:start position:0% +right solution is the only solution well +one solution is to do through some + + align:start position:0% +one solution is to do through some + + + align:start position:0% +one solution is to do through some +decentralized mechanisms including side + + align:start position:0% +decentralized mechanisms including side + + + align:start position:0% +decentralized mechanisms including side +chains or one of the favorites of the + + align:start position:0% +chains or one of the favorites of the + + + align:start position:0% +chains or one of the favorites of the +director of the Media Lab Joey Ito + + align:start position:0% +director of the Media Lab Joey Ito + + + align:start position:0% +director of the Media Lab Joey Ito +thinks maybe if we have layer two we + + align:start position:0% +thinks maybe if we have layer two we + + + align:start position:0% +thinks maybe if we have layer two we +should also have layer zero underneath + + align:start position:0% +should also have layer zero underneath + + + align:start position:0% +should also have layer zero underneath +all of these these coins underneath + + align:start position:0% +all of these these coins underneath + + + align:start position:0% +all of these these coins underneath +aetherium and bitcoin maybe there's a + + align:start position:0% +aetherium and bitcoin maybe there's a + + + align:start position:0% +aetherium and bitcoin maybe there's a +layer that we can technologically create + + align:start position:0% +layer that we can technologically create + + + align:start position:0% +layer that we can technologically create +nobody's done this yet but Joey's a + + align:start position:0% +nobody's done this yet but Joey's a + + + align:start position:0% +nobody's done this yet but Joey's a +visionary Joey we've had the first + + align:start position:0% +visionary Joey we've had the first + + + align:start position:0% +visionary Joey we've had the first +Internet service provider in Japan at + + align:start position:0% +Internet service provider in Japan at + + + align:start position:0% +Internet service provider in Japan at +the age of 23 when he got fifteen + + align:start position:0% +the age of 23 when he got fifteen + + + align:start position:0% +the age of 23 when he got fifteen +hundred dollars of computer equipment + + align:start position:0% +hundred dollars of computer equipment + + + align:start position:0% +hundred dollars of computer equipment +and put it in his bathroom and that's + + align:start position:0% +and put it in his bathroom and that's + + + align:start position:0% +and put it in his bathroom and that's +how he started yes yes his bathroom it + + align:start position:0% +how he started yes yes his bathroom it + + + align:start position:0% +how he started yes yes his bathroom it +was the only real estate he had so you + + align:start position:0% +was the only real estate he had so you + + + align:start position:0% +was the only real estate he had so you +know which way does this go you hadn't + + align:start position:0% +know which way does this go you hadn't + + + align:start position:0% +know which way does this go you hadn't +heard that about Joey yeah so it's a way + + align:start position:0% +heard that about Joey yeah so it's a way + + + align:start position:0% +heard that about Joey yeah so it's a way +to start a company and and I think far + + align:start position:0% +to start a company and and I think far + + + align:start position:0% +to start a company and and I think far +more work needs to be done so it may be + + align:start position:0% +more work needs to be done so it may be + + + align:start position:0% +more work needs to be done so it may be +solvable I'm not I'm I'm not sure and + + align:start position:0% +solvable I'm not I'm I'm not sure and + + + align:start position:0% +solvable I'm not I'm I'm not sure and +then consensus required for software + + align:start position:0% +then consensus required for software + + + align:start position:0% +then consensus required for software +updates it's a tough one + + align:start position:0% +updates it's a tough one + + + align:start position:0% +updates it's a tough one +open-source software updates which are + + align:start position:0% +open-source software updates which are + + + align:start position:0% +open-source software updates which are +not backward-compatible like can I + + align:start position:0% +not backward-compatible like can I + + + align:start position:0% +not backward-compatible like can I +update the + + align:start position:0% +update the + + + align:start position:0% +update the +software but then you can't use it for + + align:start position:0% +software but then you can't use it for + + + align:start position:0% +software but then you can't use it for +the 500000 blocks that are already out + + align:start position:0% +the 500000 blocks that are already out + + + align:start position:0% +the 500000 blocks that are already out +there in Bitcoin or in some or the + + align:start position:0% +there in Bitcoin or in some or the + + + align:start position:0% +there in Bitcoin or in some or the +millions of blocks and ether so the + + align:start position:0% +millions of blocks and ether so the + + + align:start position:0% +millions of blocks and ether so the +problem often happens that the older + + align:start position:0% +problem often happens that the older + + + align:start position:0% +problem often happens that the older +versions won't validate all the new + + align:start position:0% +versions won't validate all the new + + + align:start position:0% +versions won't validate all the new +blocks and if they won't validate all + + align:start position:0% +blocks and if they won't validate all + + + align:start position:0% +blocks and if they won't validate all +the new blocks I'm simplifying again + + align:start position:0% +the new blocks I'm simplifying again + + + align:start position:0% +the new blocks I'm simplifying again +think of like Excel and you get that + + align:start position:0% +think of like Excel and you get that + + + align:start position:0% +think of like Excel and you get that +update on Excel or word for window and + + align:start position:0% +update on Excel or word for window and + + + align:start position:0% +update on Excel or word for window and +you can't open your old files I mean + + align:start position:0% +you can't open your old files I mean + + + align:start position:0% +you can't open your old files I mean +it's a you know it's a rough lay + + align:start position:0% +it's a you know it's a rough lay + + + align:start position:0% +it's a you know it's a rough lay +definition of what what this issue is + + align:start position:0% +definition of what what this issue is + + + align:start position:0% +definition of what what this issue is +and so it leads to something called hard + + align:start position:0% +and so it leads to something called hard + + + align:start position:0% +and so it leads to something called hard +Forks and this little visual on the + + align:start position:0% +Forks and this little visual on the + + + align:start position:0% +Forks and this little visual on the +right hand side is basically what + + align:start position:0% +right hand side is basically what + + + align:start position:0% +right hand side is basically what +happens is you can't validate all the + + align:start position:0% +happens is you can't validate all the + + + align:start position:0% +happens is you can't validate all the +old blocks because the new software is + + align:start position:0% +old blocks because the new software is + + + align:start position:0% +old blocks because the new software is +kind of going beyond it a hard fork + + align:start position:0% +kind of going beyond it a hard fork + + + align:start position:0% +kind of going beyond it a hard fork +would happen is if you took two megabyte + + align:start position:0% +would happen is if you took two megabyte + + + align:start position:0% +would happen is if you took two megabyte +blocks if you made the block size bigger + + align:start position:0% +blocks if you made the block size bigger + + + align:start position:0% +blocks if you made the block size bigger +the old the old software would not take + + align:start position:0% +the old the old software would not take + + + align:start position:0% +the old the old software would not take +that I've got this right that would be a + + align:start position:0% +that I've got this right that would be a + + + align:start position:0% +that I've got this right that would be a +hard fork and so that's a that's an + + align:start position:0% +hard fork and so that's a that's an + + + align:start position:0% +hard fork and so that's a that's an +issue and it's happened the theory of + + align:start position:0% +issue and it's happened the theory of + + + align:start position:0% +issue and it's happened the theory of +network has E theorem classic and a Z + + align:start position:0% +network has E theorem classic and a Z + + + align:start position:0% +network has E theorem classic and a Z +theorem because of a hard fork that was + + align:start position:0% +theorem because of a hard fork that was + + + align:start position:0% +theorem because of a hard fork that was +encouraged by Vitalik Butera and the + + align:start position:0% +encouraged by Vitalik Butera and the + + + align:start position:0% +encouraged by Vitalik Butera and the +Bitcoin network has won from last year + + align:start position:0% +Bitcoin network has won from last year + + + align:start position:0% +Bitcoin network has won from last year +where it was this debate about block + + align:start position:0% +where it was this debate about block + + + align:start position:0% +where it was this debate about block +sizes so it's most software for decades + + align:start position:0% +sizes so it's most software for decades + + + align:start position:0% +sizes so it's most software for decades +is dealt with how do we update software + + align:start position:0% +is dealt with how do we update software + + + align:start position:0% +is dealt with how do we update software +but they can push it to us and we get it + + align:start position:0% +but they can push it to us and we get it + + + align:start position:0% +but they can push it to us and we get it +and we hit a button and we get it and + + align:start position:0% +and we hit a button and we get it and + + + align:start position:0% +and we hit a button and we get it and +after a while we get annoyed and we + + align:start position:0% +after a while we get annoyed and we + + + align:start position:0% +after a while we get annoyed and we +don't update if you're like me but the + + align:start position:0% +don't update if you're like me but the + + + align:start position:0% +don't update if you're like me but the +consensus remember this was a graph that + + align:start position:0% +consensus remember this was a graph that + + + align:start position:0% +consensus remember this was a graph that +we had the consensus always supports the + + align:start position:0% +we had the consensus always supports the + + + align:start position:0% +we had the consensus always supports the +longest chain + + align:start position:0% +longest chain + + + align:start position:0% +longest chain +if the consensus is to adopt this new + + align:start position:0% +if the consensus is to adopt this new + + + align:start position:0% +if the consensus is to adopt this new +technology and only 80 or 90% adopt it + + align:start position:0% +technology and only 80 or 90% adopt it + + + align:start position:0% +technology and only 80 or 90% adopt it +it's a question of whether the other 10 + + align:start position:0% +it's a question of whether the other 10 + + + align:start position:0% +it's a question of whether the other 10 +or 15% will keep maintaining the shorter + + align:start position:0% +or 15% will keep maintaining the shorter + + + align:start position:0% +or 15% will keep maintaining the shorter +chain and in Bitcoin cache they have and + + align:start position:0% +chain and in Bitcoin cache they have and + + + align:start position:0% +chain and in Bitcoin cache they have and +so in essence now you have two + + align:start position:0% +so in essence now you have two + + + align:start position:0% +so in essence now you have two +currencies if for some reason it + + align:start position:0% +currencies if for some reason it + + + align:start position:0% +currencies if for some reason it +atrophied and they + + align:start position:0% +atrophied and they + + + align:start position:0% +atrophied and they +stopped maintaining it then the value in + + align:start position:0% +stopped maintaining it then the value in + + + align:start position:0% +stopped maintaining it then the value in +a sense in a commercial setting might go + + align:start position:0% +a sense in a commercial setting might go + + + align:start position:0% +a sense in a commercial setting might go +to zero is your question so broadly + + align:start position:0% +to zero is your question so broadly + + + align:start position:0% +to zero is your question so broadly +speaking I think the toughest issue is + + align:start position:0% +speaking I think the toughest issue is + + + align:start position:0% +speaking I think the toughest issue is +about collective action and governance + + align:start position:0% +about collective action and governance + + + align:start position:0% +about collective action and governance +how do you get a whole group of people + + align:start position:0% +how do you get a whole group of people + + + align:start position:0% +how do you get a whole group of people +to be moving in a similar direction + + align:start position:0% +to be moving in a similar direction + + + align:start position:0% +to be moving in a similar direction +blockchain applications derived part of + + align:start position:0% +blockchain applications derived part of + + + align:start position:0% +blockchain applications derived part of +their value from participation of + + align:start position:0% +their value from participation of + + + align:start position:0% +their value from participation of +multiple parties on the network as well + + align:start position:0% +multiple parties on the network as well + + + align:start position:0% +multiple parties on the network as well +that multiple people are involved it's + + align:start position:0% +that multiple people are involved it's + + + align:start position:0% +that multiple people are involved it's +remarkable in hindsight this Satoshi + + align:start position:0% +remarkable in hindsight this Satoshi + + + align:start position:0% +remarkable in hindsight this Satoshi +Nakamoto whomever he or she was got this + + align:start position:0% +Nakamoto whomever he or she was got this + + + align:start position:0% +Nakamoto whomever he or she was got this +many people there's nearly a hundred + + align:start position:0% +many people there's nearly a hundred + + + align:start position:0% +many people there's nearly a hundred +people in this room studying this ten + + align:start position:0% +people in this room studying this ten + + + align:start position:0% +people in this room studying this ten +years later but somehow he solved a + + align:start position:0% +years later but somehow he solved a + + + align:start position:0% +years later but somehow he solved a +collective action issue because it was + + align:start position:0% +collective action issue because it was + + + align:start position:0% +collective action issue because it was +just software code back in 2009 but it's + + align:start position:0% +just software code back in 2009 but it's + + + align:start position:0% +just software code back in 2009 but it's +still the example how does Silvio + + align:start position:0% +still the example how does Silvio + + + align:start position:0% +still the example how does Silvio +McCauley with a very clever blockchain + + align:start position:0% +McCauley with a very clever blockchain + + + align:start position:0% +McCauley with a very clever blockchain +adaptation and Algar and how does he get + + align:start position:0% +adaptation and Algar and how does he get + + + align:start position:0% +adaptation and Algar and how does he get +people to start using it and until he + + align:start position:0% +people to start using it and until he + + + align:start position:0% +people to start using it and until he +starts to get people to use it + + align:start position:0% +starts to get people to use it + + + align:start position:0% +starts to get people to use it +where's the value or if you have an + + align:start position:0% +where's the value or if you have an + + + align:start position:0% +where's the value or if you have an +application that's to be file-sharing or + + align:start position:0% +application that's to be file-sharing or + + + align:start position:0% +application that's to be file-sharing or +for medical records there's a medical + + align:start position:0% +for medical records there's a medical + + + align:start position:0% +for medical records there's a medical +records project here at MIT but how do + + align:start position:0% +records project here at MIT but how do + + + align:start position:0% +records project here at MIT but how do +you start to get people to use it and + + align:start position:0% +you start to get people to use it and + + + align:start position:0% +you start to get people to use it and +you know these are solved every day in + + align:start position:0% +you know these are solved every day in + + + align:start position:0% +you know these are solved every day in +the internet space but blockchain has a + + align:start position:0% +the internet space but blockchain has a + + + align:start position:0% +the internet space but blockchain has a +little bit greater Rik wrinkles so + + align:start position:0% +little bit greater Rik wrinkles so + + + align:start position:0% +little bit greater Rik wrinkles so +there's a chicken and egg issue Priya + + align:start position:0% + + + + align:start position:0% + +question is is there some perception + + align:start position:0% +question is is there some perception + + + align:start position:0% +question is is there some perception +look can I use that word there's some + + align:start position:0% +look can I use that word there's some + + + align:start position:0% +look can I use that word there's some +perception it's not a real thing so it + + align:start position:0% +perception it's not a real thing so it + + + align:start position:0% +perception it's not a real thing so it +might not propagate and there might not + + align:start position:0% +might not propagate and there might not + + + align:start position:0% +might not propagate and there might not +be as much consumer adoption that I that + + align:start position:0% +be as much consumer adoption that I that + + + align:start position:0% +be as much consumer adoption that I that +may well be one of the commercial + + align:start position:0% +may well be one of the commercial + + + align:start position:0% +may well be one of the commercial +challenges Elon did you have someone + + align:start position:0% +challenges Elon did you have someone + + + align:start position:0% +challenges Elon did you have someone +ended up in Bitcoin was because people + + align:start position:0% +ended up in Bitcoin was because people + + + align:start position:0% +ended up in Bitcoin was because people +were interested in the innovation so in + + align:start position:0% +were interested in the innovation so in + + + align:start position:0% +were interested in the innovation so in +a very solution and then hiriam and + + align:start position:0% +a very solution and then hiriam and + + + align:start position:0% +a very solution and then hiriam and +other chains or + + align:start position:0% +other chains or + + + align:start position:0% +other chains or +basically pouring money into the + + align:start position:0% +basically pouring money into the + + + align:start position:0% +basically pouring money into the +ecosystem giving money to developers to + + align:start position:0% +ecosystem giving money to developers to + + + align:start position:0% +ecosystem giving money to developers to +develop solutions because they they are + + align:start position:0% +develop solutions because they they are + + + align:start position:0% +develop solutions because they they are +betting on every one of you as you're + + align:start position:0% +betting on every one of you as you're + + + align:start position:0% +betting on every one of you as you're +thinking about your final projects this + + align:start position:0% +thinking about your final projects this + + + align:start position:0% +thinking about your final projects this +collective action issue has multiple + + align:start position:0% +collective action issue has multiple + + + align:start position:0% +collective action issue has multiple +features one to me is the governance of + + align:start position:0% +features one to me is the governance of + + + align:start position:0% +features one to me is the governance of +the blockchain software updates which we + + align:start position:0% +the blockchain software updates which we + + + align:start position:0% +the blockchain software updates which we +said is a little bit about hard Forks + + align:start position:0% +said is a little bit about hard Forks + + + align:start position:0% +said is a little bit about hard Forks +and so forth and how do you have + + align:start position:0% +and so forth and how do you have + + + align:start position:0% +and so forth and how do you have +consensus and how centralized to the + + align:start position:0% +consensus and how centralized to the + + + align:start position:0% +consensus and how centralized to the +governance stay which we'll come back to + + align:start position:0% +governance stay which we'll come back to + + + align:start position:0% +governance stay which we'll come back to +when we talk about the Securities and + + align:start position:0% +when we talk about the Securities and + + + align:start position:0% +when we talk about the Securities and +Exchange Commission and whether it's a + + align:start position:0% +Exchange Commission and whether it's a + + + align:start position:0% +Exchange Commission and whether it's a +token that's regulated as a security so + + align:start position:0% +token that's regulated as a security so + + + align:start position:0% +token that's regulated as a security so +there's that part of governance but then + + align:start position:0% +there's that part of governance but then + + + align:start position:0% +there's that part of governance but then +there's the collective action issue that + + align:start position:0% +there's the collective action issue that + + + align:start position:0% +there's the collective action issue that +if you have a payments or medical + + align:start position:0% +if you have a payments or medical + + + align:start position:0% +if you have a payments or medical +records or or trade finance how do you + + align:start position:0% +records or or trade finance how do you + + + align:start position:0% +records or or trade finance how do you +get folks to adopt and in the banking + + align:start position:0% +get folks to adopt and in the banking + + + align:start position:0% +get folks to adopt and in the banking +sector the banks are the big the big + + align:start position:0% +sector the banks are the big the big + + + align:start position:0% +sector the banks are the big the big +sort of elephants in the room the big + + align:start position:0% +sort of elephants in the room the big + + + align:start position:0% +sort of elephants in the room the big +dominant incumbents how do you get them + + align:start position:0% +dominant incumbents how do you get them + + + align:start position:0% +dominant incumbents how do you get them +to adopt or you somehow competing away + + align:start position:0% +to adopt or you somehow competing away + + + align:start position:0% +to adopt or you somehow competing away +their profits and not having them adopt + + align:start position:0% +their profits and not having them adopt + + + align:start position:0% +their profits and not having them adopt +which is more a commercial business + + align:start position:0% +which is more a commercial business + + + align:start position:0% +which is more a commercial business +issue about collective action so the + + align:start position:0% +issue about collective action so the + + + align:start position:0% +issue about collective action so the +financial sector as we've talked about + + align:start position:0% +financial sector as we've talked about + + + align:start position:0% +financial sector as we've talked about +favors permission block chains that + + align:start position:0% +favors permission block chains that + + + align:start position:0% +favors permission block chains that +don't have as many they have some + + align:start position:0% +don't have as many they have some + + + align:start position:0% +don't have as many they have some +collective action issues but they don't + + align:start position:0% +collective action issues but they don't + + + align:start position:0% +collective action issues but they don't +have as many collective action issues + + align:start position:0% +have as many collective action issues + + + align:start position:0% +have as many collective action issues +they have four fewer scalability and + + align:start position:0% +they have four fewer scalability and + + + align:start position:0% +they have four fewer scalability and +performance issues because they say I'm + + align:start position:0% +performance issues because they say I'm + + + align:start position:0% +performance issues because they say I'm +not using proof-of-work there might be + + align:start position:0% +not using proof-of-work there might be + + + align:start position:0% +not using proof-of-work there might be +15 20 or even 75 or a hundred nodes but + + align:start position:0% +15 20 or even 75 or a hundred nodes but + + + align:start position:0% +15 20 or even 75 or a hundred nodes but +they think that way they can secure + + align:start position:0% +they think that way they can secure + + + align:start position:0% +they think that way they can secure +their privacy and security + + align:start position:0% +their privacy and security + + + align:start position:0% +their privacy and security +now medoras and Nahas paper on zk ledger + + align:start position:0% +now medoras and Nahas paper on zk ledger + + + align:start position:0% +now medoras and Nahas paper on zk ledger +might be a solution and some of those + + align:start position:0% +might be a solution and some of those + + + align:start position:0% +might be a solution and some of those +banks might start using that but I'm + + align:start position:0% +banks might start using that but I'm + + + align:start position:0% +banks might start using that but I'm +talking about 2018 I'm not talking about + + align:start position:0% +talking about 2018 I'm not talking about + + + align:start position:0% +talking about 2018 I'm not talking about +2020 or 2025 right now they're favoring + + align:start position:0% +2020 or 2025 right now they're favoring + + + align:start position:0% +2020 or 2025 right now they're favoring +permissioned closed-loop systems rather + + align:start position:0% +permissioned closed-loop systems rather + + + align:start position:0% +permissioned closed-loop systems rather +than permissionless open loose systems + + align:start position:0% +than permissionless open loose systems + + + align:start position:0% +than permissionless open loose systems +so next week we're going to be moving to + + align:start position:0% +so next week we're going to be moving to + + + align:start position:0% +so next week we're going to be moving to +public policy oh my god you're gonna get + + align:start position:0% +public policy oh my god you're gonna get + + + align:start position:0% +public policy oh my god you're gonna get +to read my testimony + + align:start position:0% +to read my testimony + + + align:start position:0% + +all 28 pages of it yeah can I get it but + + align:start position:0% +all 28 pages of it yeah can I get it but + + + align:start position:0% +all 28 pages of it yeah can I get it but +I was asked to testify in the House + + align:start position:0% +I was asked to testify in the House + + + align:start position:0% +I was asked to testify in the House +Agriculture Committee in July it's a + + align:start position:0% +Agriculture Committee in July it's a + + + align:start position:0% +Agriculture Committee in July it's a +venue I'd been at a whole bunch of times + + align:start position:0% +venue I'd been at a whole bunch of times + + + align:start position:0% +venue I'd been at a whole bunch of times +it was fun to be back in front of the + + align:start position:0% + + + + align:start position:0% + +chairman Conaway from Texas and Colin + + align:start position:0% +chairman Conaway from Texas and Colin + + + align:start position:0% +chairman Conaway from Texas and Colin +Petersen for Minnesota but yes you'll + + align:start position:0% +Petersen for Minnesota but yes you'll + + + align:start position:0% +Petersen for Minnesota but yes you'll +get to read mine it was I I knew that + + align:start position:0% +get to read mine it was I I knew that + + + align:start position:0% +get to read mine it was I I knew that +there was no legislation that was going + + align:start position:0% +there was no legislation that was going + + + align:start position:0% +there was no legislation that was going +to happen this year I want to just give + + align:start position:0% +to happen this year I want to just give + + + align:start position:0% +to happen this year I want to just give +you the feedback but some the + + align:start position:0% +you the feedback but some the + + + align:start position:0% +you the feedback but some the +Republicans run the committee they get + + align:start position:0% +Republicans run the committee they get + + + align:start position:0% +Republicans run the committee they get +to invite as many witnesses they want + + align:start position:0% +to invite as many witnesses they want + + + align:start position:0% +to invite as many witnesses they want +and then they let the minority invite + + align:start position:0% +and then they let the minority invite + + + align:start position:0% +and then they let the minority invite +one sometimes two witnesses so I got the + + align:start position:0% +one sometimes two witnesses so I got the + + + align:start position:0% +one sometimes two witnesses so I got the +call to testify because I'm like the old + + align:start position:0% +call to testify because I'm like the old + + + align:start position:0% +call to testify because I'm like the old +you know sea dog and they're bringing me + + align:start position:0% +you know sea dog and they're bringing me + + + align:start position:0% +you know sea dog and they're bringing me +in or something but it was flood but I + + align:start position:0% +in or something but it was flood but I + + + align:start position:0% +in or something but it was flood but I +it sort of I was preparing for this + + align:start position:0% +it sort of I was preparing for this + + + align:start position:0% +it sort of I was preparing for this +class anyway so I kind of wrote the + + align:start position:0% +class anyway so I kind of wrote the + + + align:start position:0% +class anyway so I kind of wrote the +testimony for you all Congress thought + + align:start position:0% +testimony for you all Congress thought + + + align:start position:0% +testimony for you all Congress thought +it was for them and it was it was but + + align:start position:0% +it was for them and it was it was but + + + align:start position:0% +it was for them and it was it was but +that's the main thing Mark Carney who + + align:start position:0% +that's the main thing Mark Carney who + + + align:start position:0% +that's the main thing Mark Carney who +runs the Bank of England wrote this + + align:start position:0% +runs the Bank of England wrote this + + + align:start position:0% +runs the Bank of England wrote this +really beautifully written piece that he + + align:start position:0% +really beautifully written piece that he + + + align:start position:0% +really beautifully written piece that he +gave in the spring about a little bit + + align:start position:0% +gave in the spring about a little bit + + + align:start position:0% +gave in the spring about a little bit +the history currency and so forth but + + align:start position:0% +the history currency and so forth but + + + align:start position:0% +the history currency and so forth but +mark also runs the financial stability + + align:start position:0% +mark also runs the financial stability + + + align:start position:0% +mark also runs the financial stability +the it so the the the Financial + + align:start position:0% +the it so the the the Financial + + + align:start position:0% +the it so the the the Financial +Stability Board which has the finance + + align:start position:0% +Stability Board which has the finance + + + align:start position:0% +Stability Board which has the finance +ministers and central bank governors and + + align:start position:0% +ministers and central bank governors and + + + align:start position:0% +ministers and central bank governors and +securities regulators from 20 countries + + align:start position:0% +securities regulators from 20 countries + + + align:start position:0% +securities regulators from 20 countries +so it's the g20 s finance heavies I used + + align:start position:0% +so it's the g20 s finance heavies I used + + + align:start position:0% +so it's the g20 s finance heavies I used +to go to that not as a finance heavy but + + align:start position:0% +to go to that not as a finance heavy but + + + align:start position:0% +to go to that not as a finance heavy but +I used to go because they wanted me + + align:start position:0% +I used to go because they wanted me + + + align:start position:0% +I used to go because they wanted me +inside the tent rather than outside the + + align:start position:0% +inside the tent rather than outside the + + + align:start position:0% +inside the tent rather than outside the +tent because we were doing derivatives + + align:start position:0% +tent because we were doing derivatives + + + align:start position:0% +tent because we were doing derivatives +reform here in the US and some of the + + align:start position:0% +reform here in the US and some of the + + + align:start position:0% +reform here in the US and some of the +foreign finance ministers had a + + align:start position:0% +foreign finance ministers had a + + + align:start position:0% +foreign finance ministers had a +different point of view and when it got + + align:start position:0% +different point of view and when it got + + + align:start position:0% +different point of view and when it got +to the place when seven finance + + align:start position:0% +to the place when seven finance + + + align:start position:0% +to the place when seven finance +ministers and it was an interesting + + align:start position:0% +ministers and it was an interesting + + + align:start position:0% +ministers and it was an interesting +group the Russian finance minister in + + align:start position:0% +group the Russian finance minister in + + + align:start position:0% +group the Russian finance minister in +the UK and the South African and four + + align:start position:0% +the UK and the South African and four + + + align:start position:0% +the UK and the South African and four +others wrote a joint letter to secretary + + align:start position:0% +others wrote a joint letter to secretary + + + align:start position:0% +others wrote a joint letter to secretary +Geithner pointing out some shall we say + + align:start position:0% +Geithner pointing out some shall we say + + + align:start position:0% +Geithner pointing out some shall we say +observations and what we were doing + + align:start position:0% +observations and what we were doing + + + align:start position:0% +observations and what we were doing +they had differences I got invited so I + + align:start position:0% +they had differences I got invited so I + + + align:start position:0% +they had differences I got invited so I +used to go I got to know mark very well + + align:start position:0% +used to go I got to know mark very well + + + align:start position:0% +used to go I got to know mark very well +but it's it's a good paper and and + + align:start position:0% +but it's it's a good paper and and + + + align:start position:0% +but it's it's a good paper and and +you'll get a sense really from I would + + align:start position:0% +you'll get a sense really from I would + + + align:start position:0% +you'll get a sense really from I would +say mark is neither a Bitcoin maximalist + + align:start position:0% +say mark is neither a Bitcoin maximalist + + + align:start position:0% +say mark is neither a Bitcoin maximalist +or minimalist but he does say don't use + + align:start position:0% +or minimalist but he does say don't use + + + align:start position:0% +or minimalist but he does say don't use +the word cryptocurrency use the term + + align:start position:0% +the word cryptocurrency use the term + + + align:start position:0% +the word cryptocurrency use the term +crypto asset so it's kind of an + + align:start position:0% +crypto asset so it's kind of an + + + align:start position:0% +crypto asset so it's kind of an +interesting piece and then I don't know + + align:start position:0% +interesting piece and then I don't know + + + align:start position:0% +interesting piece and then I don't know +how many of you are Sloan fellows that + + align:start position:0% +how many of you are Sloan fellows that + + + align:start position:0% +how many of you are Sloan fellows that +are here I recognize some of the Sloan + + align:start position:0% +are here I recognize some of the Sloan + + + align:start position:0% +are here I recognize some of the Sloan +fellows I think about 20 or 25 percent + + align:start position:0% +fellows I think about 20 or 25 percent + + + align:start position:0% +fellows I think about 20 or 25 percent +of the class or so fellas you're gonna + + align:start position:0% +of the class or so fellas you're gonna + + + align:start position:0% +of the class or so fellas you're gonna +get to see Joe Stiglitz in New York in a + + align:start position:0% +get to see Joe Stiglitz in New York in a + + + align:start position:0% +get to see Joe Stiglitz in New York in a +few weeks and I think yeah this is the + + align:start position:0% +few weeks and I think yeah this is the + + + align:start position:0% +few weeks and I think yeah this is the +CNBC piece where Joe who's Nobel + + align:start position:0% +CNBC piece where Joe who's Nobel + + + align:start position:0% +CNBC piece where Joe who's Nobel +laureate at Columbia University has a + + align:start position:0% +laureate at Columbia University has a + + + align:start position:0% +laureate at Columbia University has a +stork and distinct point of view about + + align:start position:0% +stork and distinct point of view about + + + align:start position:0% +stork and distinct point of view about +Bitcoin I've had two or three lively + + align:start position:0% +Bitcoin I've had two or three lively + + + align:start position:0% +Bitcoin I've had two or three lively +conversations with Joe about this later + + align:start position:0% +conversations with Joe about this later + + + align:start position:0% +conversations with Joe about this later +in the semester you'll read Paul Krugman + + align:start position:0% +in the semester you'll read Paul Krugman + + + align:start position:0% +in the semester you'll read Paul Krugman +in Nouriel Roubini and and and there's a + + align:start position:0% +in Nouriel Roubini and and and there's a + + + align:start position:0% +in Nouriel Roubini and and and there's a +little video of Bill Gates talking about + + align:start position:0% +little video of Bill Gates talking about + + + align:start position:0% +little video of Bill Gates talking about +Bitcoin + + align:start position:0% +Bitcoin + + + align:start position:0% +Bitcoin +I want you ought to be aware of the + + align:start position:0% +I want you ought to be aware of the + + + align:start position:0% +I want you ought to be aware of the +Bitcoin minimalist and understand what + + align:start position:0% +Bitcoin minimalist and understand what + + + align:start position:0% +Bitcoin minimalist and understand what +they're saying and I would put Joe on a + + align:start position:0% +they're saying and I would put Joe on a + + + align:start position:0% +they're saying and I would put Joe on a +one to ten scale at maybe one and a half + + align:start position:0% + + + + align:start position:0% + +or maybe two Paul you'll read Paul + + align:start position:0% +or maybe two Paul you'll read Paul + + + align:start position:0% +or maybe two Paul you'll read Paul +Krugman's piece a little later he's kind + + align:start position:0% +Krugman's piece a little later he's kind + + + align:start position:0% +Krugman's piece a little later he's kind +of down there too I can't just they + + align:start position:0% +of down there too I can't just they + + + align:start position:0% +of down there too I can't just they +can't modulate between them but I think + + align:start position:0% +can't modulate between them but I think + + + align:start position:0% +can't modulate between them but I think +it's really important to understand what + + align:start position:0% +it's really important to understand what + + + align:start position:0% +it's really important to understand what +some really great minds are thinking + + align:start position:0% +some really great minds are thinking + + + align:start position:0% +some really great minds are thinking +about this from that side as well so + + align:start position:0% +about this from that side as well so + + + align:start position:0% +about this from that side as well so +that's what the three things are for + + align:start position:0% +that's what the three things are for + + + align:start position:0% +that's what the three things are for +next week and then the conclusion I + + align:start position:0% +next week and then the conclusion I + + + align:start position:0% +next week and then the conclusion I +think that it does provide the + + align:start position:0% +think that it does provide the + + + align:start position:0% +think that it does provide the +networking but it comes with cost as we + + align:start position:0% +networking but it comes with cost as we + + + align:start position:0% +networking but it comes with cost as we +said they're a bunch of trade offs + + align:start position:0% +said they're a bunch of trade offs + + + align:start position:0% +said they're a bunch of trade offs +I think the scalability the efficiency + + align:start position:0% +I think the scalability the efficiency + + + align:start position:0% +I think the scalability the efficiency +the privacy the ones are solvable I + + align:start position:0% +the privacy the ones are solvable I + + + align:start position:0% +the privacy the ones are solvable I +can't prove it but I think in a matter + + align:start position:0% +can't prove it but I think in a matter + + + align:start position:0% +can't prove it but I think in a matter +of years and it might be three or ten + + align:start position:0% +of years and it might be three or ten + + + align:start position:0% +of years and it might be three or ten +years it won't be three to ten months + + align:start position:0% +years it won't be three to ten months + + + align:start position:0% +years it won't be three to ten months +though I think a lot of that is + + align:start position:0% +though I think a lot of that is + + + align:start position:0% +though I think a lot of that is +susceptible to the bright minds of MIT + + align:start position:0% +susceptible to the bright minds of MIT + + + align:start position:0% +susceptible to the bright minds of MIT +and elsewhere as computer scientists I + + align:start position:0% +and elsewhere as computer scientists I + + + align:start position:0% +and elsewhere as computer scientists I +think the challenges that are tougher + + align:start position:0% +think the challenges that are tougher + + + align:start position:0% +think the challenges that are tougher +it really relates to governance + + align:start position:0% +it really relates to governance + + + align:start position:0% +it really relates to governance +I think governance and collective action + + align:start position:0% +I think governance and collective action + + + align:start position:0% +I think governance and collective action +and back to those two graphs there + + align:start position:0% +and back to those two graphs there + + + align:start position:0% +and back to those two graphs there +really are places that are better to + + align:start position:0% +really are places that are better to + + + align:start position:0% +really are places that are better to +centralize then decentralize and we're + + align:start position:0% +centralize then decentralize and we're + + + align:start position:0% +centralize then decentralize and we're +gonna be exploring that for the rest of + + align:start position:0% +gonna be exploring that for the rest of + + + align:start position:0% +gonna be exploring that for the rest of +the semester together so thank you thank + + align:start position:0% +the semester together so thank you thank + + + align:start position:0% +the semester together so thank you thank +you for the veterans who do sat through + + align:start position:0% +you for the veterans who do sat through + + + align:start position:0% +you for the veterans who do sat through +all that + + align:start position:0% +all that + + + align:start position:0% +all that +[Applause] + + align:start position:0% + + + + align:start position:0% + +you \ No newline at end of file diff --git a/GQKFkoy4VOw.txt b/GQKFkoy4VOw.txt new file mode 100644 index 0000000000000000000000000000000000000000..4e3ace87eae2f308d52a80259c6d8054c7ff5b74 --- /dev/null +++ b/GQKFkoy4VOw.txt @@ -0,0 +1,6091 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +view additional materials from hundreds + + align:start position:0% +view additional materials from hundreds + + + align:start position:0% +view additional materials from hundreds +of MIT courses visit MIT opencourseware + + align:start position:0% +of MIT courses visit MIT opencourseware + + + align:start position:0% +of MIT courses visit MIT opencourseware +at ocw.mit.edu + + align:start position:0% + + + + align:start position:0% + +hi today we begin our discussion of + + align:start position:0% +hi today we begin our discussion of + + + align:start position:0% +hi today we begin our discussion of +differential equations it has been said + + align:start position:0% +differential equations it has been said + + + align:start position:0% +differential equations it has been said +that the language of the universe is + + align:start position:0% +that the language of the universe is + + + align:start position:0% +that the language of the universe is +differential equations and for this + + align:start position:0% +differential equations and for this + + + align:start position:0% +differential equations and for this +reason I would suspect from a practical + + align:start position:0% +reason I would suspect from a practical + + + align:start position:0% +reason I would suspect from a practical +point of view differential equations is + + align:start position:0% +point of view differential equations is + + + align:start position:0% +point of view differential equations is +most important for example one is use to + + align:start position:0% +most important for example one is use to + + + align:start position:0% +most important for example one is use to +stating physical principles in terms of + + align:start position:0% +stating physical principles in terms of + + + align:start position:0% +stating physical principles in terms of +rates of change to say for example that + + align:start position:0% +rates of change to say for example that + + + align:start position:0% +rates of change to say for example that +the rate of change is proportional to + + align:start position:0% +the rate of change is proportional to + + + align:start position:0% +the rate of change is proportional to +the amount present is a rather simple + + align:start position:0% +the amount present is a rather simple + + + align:start position:0% +the amount present is a rather simple +sounding physical principle the idea is + + align:start position:0% +sounding physical principle the idea is + + + align:start position:0% +sounding physical principle the idea is +knowing that the rate of change is + + align:start position:0% +knowing that the rate of change is + + + align:start position:0% +knowing that the rate of change is +proportional to the amount present we + + align:start position:0% +proportional to the amount present we + + + align:start position:0% +proportional to the amount present we +sometimes like to find out explicitly + + align:start position:0% +sometimes like to find out explicitly + + + align:start position:0% +sometimes like to find out explicitly +what the what the amount looks like as a + + align:start position:0% +what the what the amount looks like as a + + + align:start position:0% +what the what the amount looks like as a +function of time and that's what we mean + + align:start position:0% +function of time and that's what we mean + + + align:start position:0% +function of time and that's what we mean +by a solution or a general solution to + + align:start position:0% +by a solution or a general solution to + + + align:start position:0% +by a solution or a general solution to +differential equations and that will be + + align:start position:0% +differential equations and that will be + + + align:start position:0% +differential equations and that will be +our subject for our first lesson in our + + align:start position:0% +our subject for our first lesson in our + + + align:start position:0% +our subject for our first lesson in our +study of differential equations the + + align:start position:0% +study of differential equations the + + + align:start position:0% +study of differential equations the +concept of a general solution the first + + align:start position:0% +concept of a general solution the first + + + align:start position:0% +concept of a general solution the first +and simplest type of equation that we're + + align:start position:0% +and simplest type of equation that we're + + + align:start position:0% +and simplest type of equation that we're +going to talk talk about is the + + align:start position:0% +going to talk talk about is the + + + align:start position:0% +going to talk talk about is the +differential equation which we say has + + align:start position:0% +differential equation which we say has + + + align:start position:0% +differential equation which we say has +order one in other words the greatest + + align:start position:0% +order one in other words the greatest + + + align:start position:0% +order one in other words the greatest +derivative that appears is the first + + align:start position:0% +derivative that appears is the first + + + align:start position:0% +derivative that appears is the first +derivative there are no second + + align:start position:0% +derivative there are no second + + + align:start position:0% +derivative there are no second +derivatives involved in other words a + + align:start position:0% +derivatives involved in other words a + + + align:start position:0% +derivatives involved in other words a +problem where in terms of kinematics you + + align:start position:0% +problem where in terms of kinematics you + + + align:start position:0% +problem where in terms of kinematics you +are told what the velocity looks like in + + align:start position:0% +are told what the velocity looks like in + + + align:start position:0% +are told what the velocity looks like in +terms of the time uh in other words and + + align:start position:0% +terms of the time uh in other words and + + + align:start position:0% +terms of the time uh in other words and +you want to find the answer in terms of + + align:start position:0% +you want to find the answer in terms of + + + align:start position:0% +you want to find the answer in terms of +displacement dvdt equals uh DX DT equals + + align:start position:0% +displacement dvdt equals uh DX DT equals + + + align:start position:0% +displacement dvdt equals uh DX DT equals +something find what x looks like + + align:start position:0% +something find what x looks like + + + align:start position:0% +something find what x looks like +explicitly in terms of T now in general + + align:start position:0% +explicitly in terms of T now in general + + + align:start position:0% +explicitly in terms of T now in general +what we're saying is all we know about a + + align:start position:0% +what we're saying is all we know about a + + + align:start position:0% +what we're saying is all we know about a +first order differential equation is + + align:start position:0% +first order differential equation is + + + align:start position:0% +first order differential equation is +that there is some relationship between + + align:start position:0% +that there is some relationship between + + + align:start position:0% +that there is some relationship between +the independent variable X the dependent + + align:start position:0% +the independent variable X the dependent + + + align:start position:0% +the independent variable X the dependent +variable Y and dydx and the symbolic way + + align:start position:0% +variable Y and dydx and the symbolic way + + + align:start position:0% +variable Y and dydx and the symbolic way +of writing that is to say that some + + align:start position:0% +of writing that is to say that some + + + align:start position:0% +of writing that is to say that some +functions say capital f of x y and Dy DX + + align:start position:0% +functions say capital f of x y and Dy DX + + + align:start position:0% +functions say capital f of x y and Dy DX +is zero that's just a mathematical + + align:start position:0% +is zero that's just a mathematical + + + align:start position:0% +is zero that's just a mathematical +symbolism for writing down the most + + align:start position:0% +symbolism for writing down the most + + + align:start position:0% +symbolism for writing down the most +General first order differential + + align:start position:0% +General first order differential + + + align:start position:0% +General first order differential +equation now the question that comes up + + align:start position:0% +equation now the question that comes up + + + align:start position:0% +equation now the question that comes up +is twofold one is first of all does + + align:start position:0% +is twofold one is first of all does + + + align:start position:0% +is twofold one is first of all does +equation one even have a solution how do + + align:start position:0% +equation one even have a solution how do + + + align:start position:0% +equation one even have a solution how do +we know that just because we can State + + align:start position:0% +we know that just because we can State + + + align:start position:0% +we know that just because we can State +the differential equation that there is + + align:start position:0% +the differential equation that there is + + + align:start position:0% +the differential equation that there is +a specific function say Y is a function + + align:start position:0% +a specific function say Y is a function + + + align:start position:0% +a specific function say Y is a function +of X that satisfies the equation and the + + align:start position:0% +of X that satisfies the equation and the + + + align:start position:0% +of X that satisfies the equation and the +second is assuming that there is a + + align:start position:0% +second is assuming that there is a + + + align:start position:0% +second is assuming that there is a +function y as a function of X in other + + align:start position:0% +function y as a function of X in other + + + align:start position:0% +function y as a function of X in other +words that y as a function of X does + + align:start position:0% +words that y as a function of X does + + + align:start position:0% +words that y as a function of X does +satisfy this equation how do we know + + align:start position:0% +satisfy this equation how do we know + + + align:start position:0% +satisfy this equation how do we know +that that solution is unique two + + align:start position:0% +that that solution is unique two + + + align:start position:0% +that that solution is unique two +questions does the equation have a + + align:start position:0% +questions does the equation have a + + + align:start position:0% +questions does the equation have a +solution is the solution unique and I + + align:start position:0% +solution is the solution unique and I + + + align:start position:0% +solution is the solution unique and I +think that the easiest way way to + + align:start position:0% +think that the easiest way way to + + + align:start position:0% +think that the easiest way way to +illustrate this is in terms of part one + + align:start position:0% +illustrate this is in terms of part one + + + align:start position:0% +illustrate this is in terms of part one +of our course where we already solved a + + align:start position:0% +of our course where we already solved a + + + align:start position:0% +of our course where we already solved a +rather simple type of differential + + align:start position:0% +rather simple type of differential + + + align:start position:0% +rather simple type of differential +equation namely that differential + + align:start position:0% +equation namely that differential + + + align:start position:0% +equation namely that differential +equation that had the specific form dydx + + align:start position:0% +equation that had the specific form dydx + + + align:start position:0% +equation that had the specific form dydx +is some function of X in particular + + align:start position:0% +is some function of X in particular + + + align:start position:0% +is some function of X in particular +suppose I were to say find all solutions + + align:start position:0% +suppose I were to say find all solutions + + + align:start position:0% +suppose I were to say find all solutions +of dydx = 2x uh and I'll just add on + + align:start position:0% +of dydx = 2x uh and I'll just add on + + + align:start position:0% +of dydx = 2x uh and I'll just add on +here which pass through a particular + + align:start position:0% +here which pass through a particular + + + align:start position:0% +here which pass through a particular +Point x0 y z I'll come back to that in a + + align:start position:0% +Point x0 y z I'll come back to that in a + + + align:start position:0% +Point x0 y z I'll come back to that in a +moment by the way notice what I mean by + + align:start position:0% +moment by the way notice what I mean by + + + align:start position:0% +moment by the way notice what I mean by +an explicit solution if somebody says to + + align:start position:0% +an explicit solution if somebody says to + + + align:start position:0% +an explicit solution if somebody says to +me find all functions y such that Dy DX + + align:start position:0% +me find all functions y such that Dy DX + + + align:start position:0% +me find all functions y such that Dy DX +equal 2x in the language of sets notice + + align:start position:0% +equal 2x in the language of sets notice + + + align:start position:0% +equal 2x in the language of sets notice +that somebody could get kind of cute + + align:start position:0% +that somebody could get kind of cute + + + align:start position:0% +that somebody could get kind of cute +with us and say G isn't that just a set + + align:start position:0% +with us and say G isn't that just a set + + + align:start position:0% +with us and say G isn't that just a set +of all functions y such that dydx equal + + align:start position:0% +of all functions y such that dydx equal + + + align:start position:0% +of all functions y such that dydx equal +2X and the answer is that is correct of + + align:start position:0% +2X and the answer is that is correct of + + + align:start position:0% +2X and the answer is that is correct of +course that's the answer but what we + + align:start position:0% +course that's the answer but what we + + + align:start position:0% +course that's the answer but what we +mean is we would like to know what y + + align:start position:0% +mean is we would like to know what y + + + align:start position:0% +mean is we would like to know what y +looks like explicitly in terms of X in + + align:start position:0% +looks like explicitly in terms of X in + + + align:start position:0% +looks like explicitly in terms of X in +other words given x what is y this only + + align:start position:0% +other words given x what is y this only + + + align:start position:0% +other words given x what is y this only +tells me what dyd looks like explicitly + + align:start position:0% +tells me what dyd looks like explicitly + + + align:start position:0% +tells me what dyd looks like explicitly +in terms of X so what I am really + + align:start position:0% +in terms of X so what I am really + + + align:start position:0% +in terms of X so what I am really +interested in problems of this type is + + align:start position:0% +interested in problems of this type is + + + align:start position:0% +interested in problems of this type is +to convert from the set builder this + + align:start position:0% +to convert from the set builder this + + + align:start position:0% +to convert from the set builder this +implicit solution set to an explicit + + align:start position:0% +implicit solution set to an explicit + + + align:start position:0% +implicit solution set to an explicit +solution set and as a trivial review + + align:start position:0% +solution set and as a trivial review + + + align:start position:0% +solution set and as a trivial review +recall that in this case we knew that if + + align:start position:0% +recall that in this case we knew that if + + + align:start position:0% +recall that in this case we knew that if +Dy DX was 2x then y had to be x^2 + C in + + align:start position:0% +Dy DX was 2x then y had to be x^2 + C in + + + align:start position:0% +Dy DX was 2x then y had to be x^2 + C in +other words the solution set s written + + align:start position:0% +other words the solution set s written + + + align:start position:0% +other words the solution set s written +in explicit form is the set of all y + + align:start position:0% +in explicit form is the set of all y + + + align:start position:0% +in explicit form is the set of all y +such that y = x^2 + C and I suppose if + + align:start position:0% +such that y = x^2 + C and I suppose if + + + align:start position:0% +such that y = x^2 + C and I suppose if +you wanted another definition of what it + + align:start position:0% +you wanted another definition of what it + + + align:start position:0% +you wanted another definition of what it +means to solve a differential equation + + align:start position:0% +means to solve a differential equation + + + align:start position:0% +means to solve a differential equation +why couldn't we just say just like we do + + align:start position:0% +why couldn't we just say just like we do + + + align:start position:0% +why couldn't we just say just like we do +in algebra in a sense that solving a + + align:start position:0% +in algebra in a sense that solving a + + + align:start position:0% +in algebra in a sense that solving a +differential equation essentially means + + align:start position:0% +differential equation essentially means + + + align:start position:0% +differential equation essentially means +to convert from the set builder the + + align:start position:0% +to convert from the set builder the + + + align:start position:0% +to convert from the set builder the +implicit form to the explicit form so in + + align:start position:0% +implicit form to the explicit form so in + + + align:start position:0% +implicit form to the explicit form so in +other words explicitly to Express Y in + + align:start position:0% +other words explicitly to Express Y in + + + align:start position:0% +other words explicitly to Express Y in +terms of X the set of all y such that y + + align:start position:0% +terms of X the set of all y such that y + + + align:start position:0% +terms of X the set of all y such that y += x^2 + C see now I know what y looks + + align:start position:0% += x^2 + C see now I know what y looks + + + align:start position:0% += x^2 + C see now I know what y looks +like in terms of X up to an arbitrary + + align:start position:0% +like in terms of X up to an arbitrary + + + align:start position:0% +like in terms of X up to an arbitrary +constant is the solution set of the + + align:start position:0% +constant is the solution set of the + + + align:start position:0% +constant is the solution set of the +differential equation dydx = 2x now you + + align:start position:0% +differential equation dydx = 2x now you + + + align:start position:0% +differential equation dydx = 2x now you +may have noticed I said as part of the + + align:start position:0% +may have noticed I said as part of the + + + align:start position:0% +may have noticed I said as part of the +problem let's see if there is a solution + + align:start position:0% +problem let's see if there is a solution + + + align:start position:0% +problem let's see if there is a solution +which passes through a particular Point + + align:start position:0% +which passes through a particular Point + + + align:start position:0% +which passes through a particular Point +x0 y0 what I do is is I look at this + + align:start position:0% +x0 y0 what I do is is I look at this + + + align:start position:0% +x0 y0 what I do is is I look at this +particular equation and I replace X by + + align:start position:0% +particular equation and I replace X by + + + align:start position:0% +particular equation and I replace X by +x0 and Y by y0 and solve for C and by + + align:start position:0% +x0 and Y by y0 and solve for C and by + + + align:start position:0% +x0 and Y by y0 and solve for C and by +the way I would intuitively expect to be + + align:start position:0% +the way I would intuitively expect to be + + + align:start position:0% +the way I would intuitively expect to be +able to find that value of C because + + align:start position:0% +able to find that value of C because + + + align:start position:0% +able to find that value of C because +after all I have an arbitrary constant + + align:start position:0% +after all I have an arbitrary constant + + + align:start position:0% +after all I have an arbitrary constant +in here which means I have a degree of + + align:start position:0% +in here which means I have a degree of + + + align:start position:0% +in here which means I have a degree of +freedom and therefore I would suspect + + align:start position:0% +freedom and therefore I would suspect + + + align:start position:0% +freedom and therefore I would suspect +that by replacing X by x0 and Y by y z I + + align:start position:0% +that by replacing X by x0 and Y by y z I + + + align:start position:0% +that by replacing X by x0 and Y by y z I +should be able to find a specific value + + align:start position:0% +should be able to find a specific value + + + align:start position:0% +should be able to find a specific value +of C now notice what this leads to if I + + align:start position:0% +of C now notice what this leads to if I + + + align:start position:0% +of C now notice what this leads to if I +replace X by x0 y by y0 I get y0 = x02 + + + align:start position:0% +replace X by x0 y by y0 I get y0 = x02 + + + + align:start position:0% +replace X by x0 y by y0 I get y0 = x02 + +C consequently C is y0 - x 0^ 2 x0 and + + align:start position:0% +C consequently C is y0 - x 0^ 2 x0 and + + + align:start position:0% +C consequently C is y0 - x 0^ 2 x0 and +y0 were specific numbers real numbers + + align:start position:0% +y0 were specific numbers real numbers + + + align:start position:0% +y0 were specific numbers real numbers +consequently y0 - x0 2 is a specific + + align:start position:0% +consequently y0 - x0 2 is a specific + + + align:start position:0% +consequently y0 - x0 2 is a specific +number and consequently the specific + + align:start position:0% +number and consequently the specific + + + align:start position:0% +number and consequently the specific +choice of C such that the equation + + align:start position:0% +choice of C such that the equation + + + align:start position:0% +choice of C such that the equation +becomes what y = x^2 plus the constant + + align:start position:0% +becomes what y = x^2 plus the constant + + + align:start position:0% +becomes what y = x^2 plus the constant +y0 - x 0^ 2 is the only + + align:start position:0% +y0 - x 0^ 2 is the only + + + align:start position:0% +y0 - x 0^ 2 is the only +solution of what the equation dydx = 2x + + align:start position:0% +solution of what the equation dydx = 2x + + + align:start position:0% +solution of what the equation dydx = 2x +that passes through the point x0 y0 this + + align:start position:0% +that passes through the point x0 y0 this + + + align:start position:0% +that passes through the point x0 y0 this +is kind of baby stuff in terms of the + + align:start position:0% +is kind of baby stuff in terms of the + + + align:start position:0% +is kind of baby stuff in terms of the +fact that it was Elementary in part one + + align:start position:0% +fact that it was Elementary in part one + + + align:start position:0% +fact that it was Elementary in part one +of our course but remember this solution + + align:start position:0% +of our course but remember this solution + + + align:start position:0% +of our course but remember this solution +set is what it's a set of parabas which + + align:start position:0% +set is what it's a set of parabas which + + + align:start position:0% +set is what it's a set of parabas which +are essentially a a parallel family of + + align:start position:0% +are essentially a a parallel family of + + + align:start position:0% +are essentially a a parallel family of +parabas and which is sort of saying is + + align:start position:0% +parabas and which is sort of saying is + + + align:start position:0% +parabas and which is sort of saying is +Gee it seems obvious geometrically that + + align:start position:0% +Gee it seems obvious geometrically that + + + align:start position:0% +Gee it seems obvious geometrically that +since I have this infinite family of + + align:start position:0% +since I have this infinite family of + + + align:start position:0% +since I have this infinite family of +parallel parabas that specifying a point + + align:start position:0% +parallel parabas that specifying a point + + + align:start position:0% +parallel parabas that specifying a point +that has to beond the parabola uniquely + + align:start position:0% +that has to beond the parabola uniquely + + + align:start position:0% +that has to beond the parabola uniquely +determines a member of that family at + + align:start position:0% +determines a member of that family at + + + align:start position:0% +determines a member of that family at +any rate I don't want to be labor this + + align:start position:0% +any rate I don't want to be labor this + + + align:start position:0% +any rate I don't want to be labor this +point I want to get to the greater + + align:start position:0% +point I want to get to the greater + + + align:start position:0% +point I want to get to the greater +subtleties that come up in handling + + align:start position:0% +subtleties that come up in handling + + + align:start position:0% +subtleties that come up in handling +first order differential equations so + + align:start position:0% +first order differential equations so + + + align:start position:0% +first order differential equations so +I've picked a slightly tougher problem + + align:start position:0% +I've picked a slightly tougher problem + + + align:start position:0% +I've picked a slightly tougher problem +for example two example two and by the + + align:start position:0% +for example two example two and by the + + + align:start position:0% +for example two example two and by the +way this is a special equation I've + + align:start position:0% +way this is a special equation I've + + + align:start position:0% +way this is a special equation I've +picked it's known as Claro's equation + + align:start position:0% +picked it's known as Claro's equation + + + align:start position:0% +picked it's known as Claro's equation +and the equation is this it's y = x dydx + + align:start position:0% +and the equation is this it's y = x dydx + + + align:start position:0% +and the equation is this it's y = x dydx +minus Dy dx^ 2 Claro's equation is any + + align:start position:0% +minus Dy dx^ 2 Claro's equation is any + + + align:start position:0% +minus Dy dx^ 2 Claro's equation is any +equation which has the form y = x * Dy + + align:start position:0% +equation which has the form y = x * Dy + + + align:start position:0% +equation which has the form y = x * Dy +DX plus something which depends only on + + align:start position:0% +DX plus something which depends only on + + + align:start position:0% +DX plus something which depends only on +Dy DX in other words rather than write + + align:start position:0% +Dy DX in other words rather than write + + + align:start position:0% +Dy DX in other words rather than write +this uh in an abstract form I decided to + + align:start position:0% +this uh in an abstract form I decided to + + + align:start position:0% +this uh in an abstract form I decided to +pick a particular application of this + + align:start position:0% +pick a particular application of this + + + align:start position:0% +pick a particular application of this +and that is let's just pick this + + align:start position:0% +and that is let's just pick this + + + align:start position:0% +and that is let's just pick this +particular example that's one special + + align:start position:0% +particular example that's one special + + + align:start position:0% +particular example that's one special +form of claro equation that's what y = x + + align:start position:0% +form of claro equation that's what y = x + + + align:start position:0% +form of claro equation that's what y = x +dydx minus Dy dx^ 2 x * Dy DX and what's + + align:start position:0% +dydx minus Dy dx^ 2 x * Dy DX and what's + + + align:start position:0% +dydx minus Dy dx^ 2 x * Dy DX and what's +left is a function of dydx alone at any + + align:start position:0% +left is a function of dydx alone at any + + + align:start position:0% +left is a function of dydx alone at any +rate it turns out that that one explicit + + align:start position:0% +rate it turns out that that one explicit + + + align:start position:0% +rate it turns out that that one explicit +solution of claro equation is very + + align:start position:0% +solution of claro equation is very + + + align:start position:0% +solution of claro equation is very +interesting thing is you simply replace + + align:start position:0% +interesting thing is you simply replace + + + align:start position:0% +interesting thing is you simply replace +dydx by C very amazing thing in other + + align:start position:0% +dydx by C very amazing thing in other + + + align:start position:0% +dydx by C very amazing thing in other +words if you have a claro equation and + + align:start position:0% +words if you have a claro equation and + + + align:start position:0% +words if you have a claro equation and +you want a solution every place you see + + align:start position:0% +you want a solution every place you see + + + align:start position:0% +you want a solution every place you see +dydx replace it by C for example in this + + align:start position:0% +dydx replace it by C for example in this + + + align:start position:0% +dydx replace it by C for example in this +case I would get what Y is equal to XC + + align:start position:0% +case I would get what Y is equal to XC + + + align:start position:0% +case I would get what Y is equal to XC +or CX I guess you like to write the + + align:start position:0% +or CX I guess you like to write the + + + align:start position:0% +or CX I guess you like to write the +constant first CX - c^ 2 which by the + + align:start position:0% +constant first CX - c^ 2 which by the + + + align:start position:0% +constant first CX - c^ 2 which by the +way is what a straight line whose slope + + align:start position:0% +way is what a straight line whose slope + + + align:start position:0% +way is what a straight line whose slope +is C and whose intercept is minus c^2 by + + align:start position:0% +is C and whose intercept is minus c^2 by + + + align:start position:0% +is C and whose intercept is minus c^2 by +the way the proof that this is is a + + align:start position:0% +the way the proof that this is is a + + + align:start position:0% +the way the proof that this is is a +solution is simply differentiate this + + align:start position:0% +solution is simply differentiate this + + + align:start position:0% +solution is simply differentiate this +you get that Dy DX equal C since C is + + align:start position:0% +you get that Dy DX equal C since C is + + + align:start position:0% +you get that Dy DX equal C since C is +dydx every place you see a c replace it + + align:start position:0% +dydx every place you see a c replace it + + + align:start position:0% +dydx every place you see a c replace it +by Dy DX and that will give you what y = + + align:start position:0% +by Dy DX and that will give you what y = + + + align:start position:0% +by Dy DX and that will give you what y = +x dydx minus Dy dx^ 2 I'll give you more + + align:start position:0% +x dydx minus Dy dx^ 2 I'll give you more + + + align:start position:0% +x dydx minus Dy dx^ 2 I'll give you more +on that in the exercises on how one + + align:start position:0% +on that in the exercises on how one + + + align:start position:0% +on that in the exercises on how one +solves claro equations I want it for + + align:start position:0% +solves claro equations I want it for + + + align:start position:0% +solves claro equations I want it for +illustrative purposes here so anyway + + align:start position:0% +illustrative purposes here so anyway + + + align:start position:0% +illustrative purposes here so anyway +this is a solution of this particular + + align:start position:0% +this is a solution of this particular + + + align:start position:0% +this is a solution of this particular +equation and it's only one solution I I + + align:start position:0% +equation and it's only one solution I I + + + align:start position:0% +equation and it's only one solution I I +don't know if there are other Solutions + + align:start position:0% +don't know if there are other Solutions + + + align:start position:0% +don't know if there are other Solutions +or what have you the next question that + + align:start position:0% +or what have you the next question that + + + align:start position:0% +or what have you the next question that +I would investigate here just as in the + + align:start position:0% +I would investigate here just as in the + + + align:start position:0% +I would investigate here just as in the +previous case I would say G I wonder + + align:start position:0% +previous case I would say G I wonder + + + align:start position:0% +previous case I would say G I wonder +what C must be if I want a solution + + align:start position:0% +what C must be if I want a solution + + + align:start position:0% +what C must be if I want a solution +curve to pass through the point x0 y0 in + + align:start position:0% +curve to pass through the point x0 y0 in + + + align:start position:0% +curve to pass through the point x0 y0 in +the XY + + align:start position:0% +the XY + + + align:start position:0% +the XY +plane so what I do purely algebraically + + align:start position:0% +plane so what I do purely algebraically + + + align:start position:0% +plane so what I do purely algebraically +is I replace X by x0 y by y0 and solve + + align:start position:0% +is I replace X by x0 y by y0 and solve + + + align:start position:0% +is I replace X by x0 y by y0 and solve +the resulting equation for C namely y0 = + + align:start position:0% +the resulting equation for C namely y0 = + + + align:start position:0% +the resulting equation for C namely y0 = +x0 cus c^ 2 and I now observe remember X + + align:start position:0% +x0 cus c^ 2 and I now observe remember X + + + align:start position:0% +x0 cus c^ 2 and I now observe remember X +and Y look like variables with the + + align:start position:0% +and Y look like variables with the + + + align:start position:0% +and Y look like variables with the +subscript zero they represent fixed X + + align:start position:0% +subscript zero they represent fixed X + + + align:start position:0% +subscript zero they represent fixed X +and Y coordinates of a point C is the + + align:start position:0% +and Y coordinates of a point C is the + + + align:start position:0% +and Y coordinates of a point C is the +only variable in here in other words + + align:start position:0% +only variable in here in other words + + + align:start position:0% +only variable in here in other words +this is a quadratic equation in C and + + align:start position:0% +this is a quadratic equation in C and + + + align:start position:0% +this is a quadratic equation in C and +solving this quadratic equation by the + + align:start position:0% +solving this quadratic equation by the + + + align:start position:0% +solving this quadratic equation by the +quadratic formula I find that c is equal + + align:start position:0% +quadratic formula I find that c is equal + + + align:start position:0% +quadratic formula I find that c is equal +to this expression here remembering that + + align:start position:0% +to this expression here remembering that + + + align:start position:0% +to this expression here remembering that +we're dealing with real variables + + align:start position:0% +we're dealing with real variables + + + align:start position:0% +we're dealing with real variables +I now know that I'm in trouble if this + + align:start position:0% +I now know that I'm in trouble if this + + + align:start position:0% +I now know that I'm in trouble if this +thing here happens to be negative in + + align:start position:0% +thing here happens to be negative in + + + align:start position:0% +thing here happens to be negative in +other words if this is negative I have + + align:start position:0% +other words if this is negative I have + + + align:start position:0% +other words if this is negative I have +an imaginary number when I take the + + align:start position:0% +an imaginary number when I take the + + + align:start position:0% +an imaginary number when I take the +square root in other words there will be + + align:start position:0% +square root in other words there will be + + + align:start position:0% +square root in other words there will be +no solution at least of this particular + + align:start position:0% +no solution at least of this particular + + + align:start position:0% +no solution at least of this particular +type there'll be no solution to this + + align:start position:0% +type there'll be no solution to this + + + align:start position:0% +type there'll be no solution to this +equation if y happens to be if y0 is + + align:start position:0% +equation if y happens to be if y0 is + + + align:start position:0% +equation if y happens to be if y0 is +greater than 1/4 x 0^ 2 and that means + + align:start position:0% +greater than 1/4 x 0^ 2 and that means + + + align:start position:0% +greater than 1/4 x 0^ 2 and that means +there will be no solution if you're + + align:start position:0% +there will be no solution if you're + + + align:start position:0% +there will be no solution if you're +above the parabola y = 1/4 X2 + + align:start position:0% +above the parabola y = 1/4 X2 + + + align:start position:0% +above the parabola y = 1/4 X2 +remember the set of all points X comma y + + align:start position:0% +remember the set of all points X comma y + + + align:start position:0% +remember the set of all points X comma y +for which Y is greater than 1/4 x^2 + + align:start position:0% +for which Y is greater than 1/4 x^2 + + + align:start position:0% +for which Y is greater than 1/4 x^2 +means you're above the parabola y = 1/4 + + align:start position:0% +means you're above the parabola y = 1/4 + + + align:start position:0% +means you're above the parabola y = 1/4 +x^2 because on that Parabola since Y is + + align:start position:0% +x^2 because on that Parabola since Y is + + + align:start position:0% +x^2 because on that Parabola since Y is +equal to 1/4 x^2 you would have to go + + align:start position:0% +equal to 1/4 x^2 you would have to go + + + align:start position:0% +equal to 1/4 x^2 you would have to go +above that to make y greater than 1/4 + + align:start position:0% +above that to make y greater than 1/4 + + + align:start position:0% +above that to make y greater than 1/4 +x^2 by the way you see all this proves + + align:start position:0% +x^2 by the way you see all this proves + + + align:start position:0% +x^2 by the way you see all this proves +is that there is no solution of this + + align:start position:0% +is that there is no solution of this + + + align:start position:0% +is that there is no solution of this +type to this particular equation if + + align:start position:0% +type to this particular equation if + + + align:start position:0% +type to this particular equation if +you're above the parabola y = 1/4x squ + + align:start position:0% +you're above the parabola y = 1/4x squ + + + align:start position:0% +you're above the parabola y = 1/4x squ +the question is what if I didn't give + + align:start position:0% +the question is what if I didn't give + + + align:start position:0% +the question is what if I didn't give +you this as a hint suppose I just gave + + align:start position:0% +you this as a hint suppose I just gave + + + align:start position:0% +you this as a hint suppose I just gave +you this equation didn't even give you a + + align:start position:0% +you this equation didn't even give you a + + + align:start position:0% +you this equation didn't even give you a +hint as to what the solution should be + + align:start position:0% +hint as to what the solution should be + + + align:start position:0% +hint as to what the solution should be +and just said tell me where there will + + align:start position:0% +and just said tell me where there will + + + align:start position:0% +and just said tell me where there will +be Solutions notice that you did not + + align:start position:0% +be Solutions notice that you did not + + + align:start position:0% +be Solutions notice that you did not +need this piece of information to get + + align:start position:0% +need this piece of information to get + + + align:start position:0% +need this piece of information to get +started on this problem namely all you + + align:start position:0% +started on this problem namely all you + + + align:start position:0% +started on this problem namely all you +had to say was G this is a quadratic + + align:start position:0% +had to say was G this is a quadratic + + + align:start position:0% +had to say was G this is a quadratic +equation in dydx let me solve this + + align:start position:0% +equation in dydx let me solve this + + + align:start position:0% +equation in dydx let me solve this +quadratic equation see what I could have + + align:start position:0% +quadratic equation see what I could have + + + align:start position:0% +quadratic equation see what I could have +done was what I could have said Dy dx^ 2 + + align:start position:0% +done was what I could have said Dy dx^ 2 + + + align:start position:0% +done was what I could have said Dy dx^ 2 +- x Dy DX + y = 0 and then solve that + + align:start position:0% +- x Dy DX + y = 0 and then solve that + + + align:start position:0% +- x Dy DX + y = 0 and then solve that +equation for dydx without boring you + + align:start position:0% +equation for dydx without boring you + + + align:start position:0% +equation for dydx without boring you +with the details of the quadratic + + align:start position:0% +with the details of the quadratic + + + align:start position:0% +with the details of the quadratic +formula all over again it would have + + align:start position:0% +formula all over again it would have + + + align:start position:0% +formula all over again it would have +turned out more generally that Dy DX is + + align:start position:0% +turned out more generally that Dy DX is + + + align:start position:0% +turned out more generally that Dy DX is +equal to X plus or minus the < TK of x^2 + + align:start position:0% +equal to X plus or minus the < TK of x^2 + + + align:start position:0% +equal to X plus or minus the < TK of x^2 +- 4 y / 2 and then I would have seen + + align:start position:0% +- 4 y / 2 and then I would have seen + + + align:start position:0% +- 4 y / 2 and then I would have seen +right from + + align:start position:0% +right from + + + align:start position:0% +right from +this without even knowing where the + + align:start position:0% +this without even knowing where the + + + align:start position:0% +this without even knowing where the +solution was that Dy DX isn't even a + + align:start position:0% +solution was that Dy DX isn't even a + + + align:start position:0% +solution was that Dy DX isn't even a +real number remember Dy DX geometrically + + align:start position:0% +real number remember Dy DX geometrically + + + align:start position:0% +real number remember Dy DX geometrically +is slope and slope is real so this + + align:start position:0% +is slope and slope is real so this + + + align:start position:0% +is slope and slope is real so this +wouldn't even be a real number if y was + + align:start position:0% +wouldn't even be a real number if y was + + + align:start position:0% +wouldn't even be a real number if y was +greater than 1/4 x^2 so no matter what + + align:start position:0% +greater than 1/4 x^2 so no matter what + + + align:start position:0% +greater than 1/4 x^2 so no matter what +the solution is the geometry of this + + align:start position:0% +the solution is the geometry of this + + + align:start position:0% +the solution is the geometry of this +problem tells me there can be no + + align:start position:0% +problem tells me there can be no + + + align:start position:0% +problem tells me there can be no +solution if Y is greater than 1/4 x^2 + + align:start position:0% +solution if Y is greater than 1/4 x^2 + + + align:start position:0% +solution if Y is greater than 1/4 x^2 +and what that means is if I draw the + + align:start position:0% +and what that means is if I draw the + + + align:start position:0% +and what that means is if I draw the +graph now see in other words this is the + + align:start position:0% +graph now see in other words this is the + + + align:start position:0% +graph now see in other words this is the +x axis the Y AIS this is the the + + align:start position:0% +x axis the Y AIS this is the the + + + align:start position:0% +x axis the Y AIS this is the the +parabola yal 4x^2 there are no solutions + + align:start position:0% +parabola yal 4x^2 there are no solutions + + + align:start position:0% +parabola yal 4x^2 there are no solutions +that pass through any points in here no + + align:start position:0% +that pass through any points in here no + + + align:start position:0% +that pass through any points in here no +Solutions in here by the way the plus or + + align:start position:0% +Solutions in here by the way the plus or + + + align:start position:0% +Solutions in here by the way the plus or +minus sign here is relatively + + align:start position:0% +minus sign here is relatively + + + align:start position:0% +minus sign here is relatively +unimportant what it means is dydx is a + + align:start position:0% +unimportant what it means is dydx is a + + + align:start position:0% +unimportant what it means is dydx is a +double valued function we we would solve + + align:start position:0% +double valued function we we would solve + + + align:start position:0% +double valued function we we would solve +this in real life as two separate + + align:start position:0% +this in real life as two separate + + + align:start position:0% +this in real life as two separate +problems namely dydx = X plus the squ < + + align:start position:0% +problems namely dydx = X plus the squ < + + + align:start position:0% +problems namely dydx = X plus the squ < +TK x^2 - 4 Y /2 and dydx is x - the < TK + + align:start position:0% +TK x^2 - 4 Y /2 and dydx is x - the < TK + + + align:start position:0% +TK x^2 - 4 Y /2 and dydx is x - the < TK +of x^2 - 4 y/2 notice that that the plus + + align:start position:0% +of x^2 - 4 y/2 notice that that the plus + + + align:start position:0% +of x^2 - 4 y/2 notice that that the plus +of minus sign has no bearing on the fact + + align:start position:0% +of minus sign has no bearing on the fact + + + align:start position:0% +of minus sign has no bearing on the fact +that the crucial point is that y must be + + align:start position:0% +that the crucial point is that y must be + + + align:start position:0% +that the crucial point is that y must be +no greater than 1 4 + + align:start position:0% +no greater than 1 4 + + + align:start position:0% +no greater than 1 4 +x^2 all right by way if you want to see + + align:start position:0% +x^2 all right by way if you want to see + + + align:start position:0% +x^2 all right by way if you want to see +this geometrically notice that y = CX - + + align:start position:0% +this geometrically notice that y = CX - + + + align:start position:0% +this geometrically notice that y = CX - +c s is what kind of a line it's the + + align:start position:0% +c s is what kind of a line it's the + + + align:start position:0% +c s is what kind of a line it's the +straight line whose Y intercept is minus + + align:start position:0% +straight line whose Y intercept is minus + + + align:start position:0% +straight line whose Y intercept is minus +c^ 2 notice that minus c s is negative + + align:start position:0% +c^ 2 notice that minus c s is negative + + + align:start position:0% +c^ 2 notice that minus c s is negative +whether C is positive or negative + + align:start position:0% +whether C is positive or negative + + + align:start position:0% +whether C is positive or negative +because the square c^ s can't be + + align:start position:0% +because the square c^ s can't be + + + align:start position:0% +because the square c^ s can't be +negative so minus c^ s can't be positive + + align:start position:0% +negative so minus c^ s can't be positive + + + align:start position:0% +negative so minus c^ s can't be positive +notice however if C is positive C is the + + align:start position:0% +notice however if C is positive C is the + + + align:start position:0% +notice however if C is positive C is the +slope of this line if C is positive the + + align:start position:0% +slope of this line if C is positive the + + + align:start position:0% +slope of this line if C is positive the +straight line goes through this point + + align:start position:0% +straight line goes through this point + + + align:start position:0% +straight line goes through this point +all right and has this slope if C is + + align:start position:0% +all right and has this slope if C is + + + align:start position:0% +all right and has this slope if C is +negative it goes through this point with + + align:start position:0% +negative it goes through this point with + + + align:start position:0% +negative it goes through this point with +this slope there's a very amazing + + align:start position:0% +this slope there's a very amazing + + + align:start position:0% +this slope there's a very amazing +property that the parabola 1/4 x^2 has + + align:start position:0% +property that the parabola 1/4 x^2 has + + + align:start position:0% +property that the parabola 1/4 x^2 has +with respect to this family of straight + + align:start position:0% +with respect to this family of straight + + + align:start position:0% +with respect to this family of straight +lines and I'll also talk about that more + + align:start position:0% +lines and I'll also talk about that more + + + align:start position:0% +lines and I'll also talk about that more +in the exercises the parabola y = 1/4 + + align:start position:0% +in the exercises the parabola y = 1/4 + + + align:start position:0% +in the exercises the parabola y = 1/4 +x^2 is called the envelope of this + + align:start position:0% +x^2 is called the envelope of this + + + align:start position:0% +x^2 is called the envelope of this +family of straight lines the amazing + + align:start position:0% +family of straight lines the amazing + + + align:start position:0% +family of straight lines the amazing +thing is that every straight line in + + align:start position:0% +thing is that every straight line in + + + align:start position:0% +thing is that every straight line in +this family is tangent to this Parabola + + align:start position:0% +this family is tangent to this Parabola + + + align:start position:0% +this family is tangent to this Parabola +and conversely the tangent line at any + + align:start position:0% +and conversely the tangent line at any + + + align:start position:0% +and conversely the tangent line at any +point of this Parabola is a line that + + align:start position:0% +point of this Parabola is a line that + + + align:start position:0% +point of this Parabola is a line that +belongs to this family and that leads to + + align:start position:0% +belongs to this family and that leads to + + + align:start position:0% +belongs to this family and that leads to +a very remarkable thing which is not + + align:start position:0% +a very remarkable thing which is not + + + align:start position:0% +a very remarkable thing which is not +immediately intuitively obvious and that + + align:start position:0% +immediately intuitively obvious and that + + + align:start position:0% +immediately intuitively obvious and that +is in particular it must mean that the + + align:start position:0% +is in particular it must mean that the + + + align:start position:0% +is in particular it must mean that the +parabola itself must be a solution of my + + align:start position:0% +parabola itself must be a solution of my + + + align:start position:0% +parabola itself must be a solution of my +differential equation you see after all + + align:start position:0% +differential equation you see after all + + + align:start position:0% +differential equation you see after all +if I pick a point now that's on the + + align:start position:0% +if I pick a point now that's on the + + + align:start position:0% +if I pick a point now that's on the +parabola and draw the tangent line in + + align:start position:0% +parabola and draw the tangent line in + + + align:start position:0% +parabola and draw the tangent line in +here that tangent line belongs to this + + align:start position:0% +here that tangent line belongs to this + + + align:start position:0% +here that tangent line belongs to this +family because this point is on this + + align:start position:0% +family because this point is on this + + + align:start position:0% +family because this point is on this +tangent line it must be a solution to + + align:start position:0% +tangent line it must be a solution to + + + align:start position:0% +tangent line it must be a solution to +the original differential equation but + + align:start position:0% +the original differential equation but + + + align:start position:0% +the original differential equation but +that point is also on the parabola the + + align:start position:0% +that point is also on the parabola the + + + align:start position:0% +that point is also on the parabola the +point doesn't know whether I'm + + align:start position:0% +point doesn't know whether I'm + + + align:start position:0% +point doesn't know whether I'm +considering it as being part of the + + align:start position:0% +considering it as being part of the + + + align:start position:0% +considering it as being part of the +parabola or part of the uh family of + + align:start position:0% +parabola or part of the uh family of + + + align:start position:0% +parabola or part of the uh family of +straight lines consequently what it + + align:start position:0% +straight lines consequently what it + + + align:start position:0% +straight lines consequently what it +means is that this Parabola must also + + align:start position:0% +means is that this Parabola must also + + + align:start position:0% +means is that this Parabola must also +satisfy the differential equation and + + align:start position:0% +satisfy the differential equation and + + + align:start position:0% +satisfy the differential equation and +the best way of proving that is to show + + align:start position:0% +the best way of proving that is to show + + + align:start position:0% +the best way of proving that is to show +you that it does satisfy the equation + + align:start position:0% +you that it does satisfy the equation + + + align:start position:0% +you that it does satisfy the equation +namely if y = 1/4 x^2 notice that d y DX + + align:start position:0% +namely if y = 1/4 x^2 notice that d y DX + + + align:start position:0% +namely if y = 1/4 x^2 notice that d y DX +is x/ 2 consequently Dy dx^ 2 is x^2 4 + + align:start position:0% +is x/ 2 consequently Dy dx^ 2 is x^2 4 + + + align:start position:0% +is x/ 2 consequently Dy dx^ 2 is x^2 4 +the differential equation I'm trying to + + align:start position:0% +the differential equation I'm trying to + + + align:start position:0% +the differential equation I'm trying to +satisfy is this one if I replace y by + + align:start position:0% +satisfy is this one if I replace y by + + + align:start position:0% +satisfy is this one if I replace y by +1/4 x^2 dydx by + + align:start position:0% +1/4 x^2 dydx by + + + align:start position:0% +1/4 x^2 dydx by +x/2 and look at what this says it says + + align:start position:0% +x/2 and look at what this says it says + + + align:start position:0% +x/2 and look at what this says it says +x^2 / 4 is equal to x^2 / 2 - x^2 over 4 + + align:start position:0% +x^2 / 4 is equal to x^2 / 2 - x^2 over 4 + + + align:start position:0% +x^2 / 4 is equal to x^2 / 2 - x^2 over 4 +which of course is x^2 over 4 and indeed + + align:start position:0% +which of course is x^2 over 4 and indeed + + + align:start position:0% +which of course is x^2 over 4 and indeed +the parabola does satisfy this equation + + align:start position:0% +the parabola does satisfy this equation + + + align:start position:0% +the parabola does satisfy this equation +and now you see we've run into a very + + align:start position:0% +and now you see we've run into a very + + + align:start position:0% +and now you see we've run into a very +interesting uh situation here namely on + + align:start position:0% +interesting uh situation here namely on + + + align:start position:0% +interesting uh situation here namely on +the parabola y = 1/4 x^2 y = x Dy dxus + + align:start position:0% +the parabola y = 1/4 x^2 y = x Dy dxus + + + align:start position:0% +the parabola y = 1/4 x^2 y = x Dy dxus +Dy dx^ 2 has at least two solutions + + align:start position:0% +Dy dx^ 2 has at least two solutions + + + align:start position:0% +Dy dx^ 2 has at least two solutions +namely a member of the family of + + align:start position:0% +namely a member of the family of + + + align:start position:0% +namely a member of the family of +straight lines y = cxus c^2 and also the + + align:start position:0% +straight lines y = cxus c^2 and also the + + + align:start position:0% +straight lines y = cxus c^2 and also the +parabola y = 1/4 + + align:start position:0% +parabola y = 1/4 + + + align:start position:0% +parabola y = 1/4 +x^2 remember at the beginning of our + + align:start position:0% +x^2 remember at the beginning of our + + + align:start position:0% +x^2 remember at the beginning of our +lecture today we mentioned two questions + + align:start position:0% +lecture today we mentioned two questions + + + align:start position:0% +lecture today we mentioned two questions +first of all does the differential + + align:start position:0% +first of all does the differential + + + align:start position:0% +first of all does the differential +equation have a solution and if it does + + align:start position:0% +equation have a solution and if it does + + + align:start position:0% +equation have a solution and if it does +have a solution is the solution unique + + align:start position:0% +have a solution is the solution unique + + + align:start position:0% +have a solution is the solution unique +what we've shown so far is that on the + + align:start position:0% +what we've shown so far is that on the + + + align:start position:0% +what we've shown so far is that on the +parabola the solution is not unique + + align:start position:0% +parabola the solution is not unique + + + align:start position:0% +parabola the solution is not unique +namely there are two solutions on the + + align:start position:0% +namely there are two solutions on the + + + align:start position:0% +namely there are two solutions on the +parabola and we've shown that above the + + align:start position:0% +parabola and we've shown that above the + + + align:start position:0% +parabola and we've shown that above the +parabola the equation has no Solutions + + align:start position:0% +parabola the equation has no Solutions + + + align:start position:0% +parabola the equation has no Solutions +consequently the answers to both + + align:start position:0% +consequently the answers to both + + + align:start position:0% +consequently the answers to both +questions one and two can be in the + + align:start position:0% +questions one and two can be in the + + + align:start position:0% +questions one and two can be in the +negative and this is what makes + + align:start position:0% +negative and this is what makes + + + align:start position:0% +negative and this is what makes +differential equations a very tough + + align:start position:0% +differential equations a very tough + + + align:start position:0% +differential equations a very tough +subject and why it's difficult to talk + + align:start position:0% +subject and why it's difficult to talk + + + align:start position:0% +subject and why it's difficult to talk +about the solution or a solution or what + + align:start position:0% +about the solution or a solution or what + + + align:start position:0% +about the solution or a solution or what +have you but fortunately there is a key + + align:start position:0% +have you but fortunately there is a key + + + align:start position:0% +have you but fortunately there is a key +theorem which we have at our disposal a + + align:start position:0% +theorem which we have at our disposal a + + + align:start position:0% +theorem which we have at our disposal a +theorem Which is far more difficult to + + align:start position:0% +theorem Which is far more difficult to + + + align:start position:0% +theorem Which is far more difficult to +prove than it is to State and memorize + + align:start position:0% +prove than it is to State and memorize + + + align:start position:0% +prove than it is to State and memorize +and I will settle right now for just + + align:start position:0% +and I will settle right now for just + + + align:start position:0% +and I will settle right now for just +stating the theorem and having you see + + align:start position:0% +stating the theorem and having you see + + + align:start position:0% +stating the theorem and having you see +what it means the key theorem is this + + align:start position:0% +what it means the key theorem is this + + + align:start position:0% +what it means the key theorem is this +let's assume for the sake of argument + + align:start position:0% +let's assume for the sake of argument + + + align:start position:0% +let's assume for the sake of argument +that we can write our differential + + align:start position:0% +that we can write our differential + + + align:start position:0% +that we can write our differential +equation explicitly in terms of dydx in + + align:start position:0% +equation explicitly in terms of dydx in + + + align:start position:0% +equation explicitly in terms of dydx in +other words that dydx is explicitly some + + align:start position:0% +other words that dydx is explicitly some + + + align:start position:0% +other words that dydx is explicitly some +function of X and Y if it turns out that + + align:start position:0% +function of X and Y if it turns out that + + + align:start position:0% +function of X and Y if it turns out that +that F and its partial with respect to Y + + align:start position:0% +that F and its partial with respect to Y + + + align:start position:0% +that F and its partial with respect to Y +are continuous in some region R then at + + align:start position:0% +are continuous in some region R then at + + + align:start position:0% +are continuous in some region R then at +each point in R there is a unique + + align:start position:0% +each point in R there is a unique + + + align:start position:0% +each point in R there is a unique +solution of dydx equal f ofx y which + + align:start position:0% +solution of dydx equal f ofx y which + + + align:start position:0% +solution of dydx equal f ofx y which +passes through x0 y0 you see notice that + + align:start position:0% +passes through x0 y0 you see notice that + + + align:start position:0% +passes through x0 y0 you see notice that +in the particular problem that we were + + align:start position:0% +in the particular problem that we were + + + align:start position:0% +in the particular problem that we were +just dealing with what was f ofx y f ofx + + align:start position:0% +just dealing with what was f ofx y f ofx + + + align:start position:0% +just dealing with what was f ofx y f ofx +y was this function here notice that f + + align:start position:0% +y was this function here notice that f + + + align:start position:0% +y was this function here notice that f +ofx y will be continuous as long as this + + align:start position:0% +ofx y will be continuous as long as this + + + align:start position:0% +ofx y will be continuous as long as this +expression exists in other words F of XY + + align:start position:0% +expression exists in other words F of XY + + + align:start position:0% +expression exists in other words F of XY +will be continuous as long as Y is less + + align:start position:0% +will be continuous as long as Y is less + + + align:start position:0% +will be continuous as long as Y is less +than or equal to 1/4 x^2 what about the + + align:start position:0% +than or equal to 1/4 x^2 what about the + + + align:start position:0% +than or equal to 1/4 x^2 what about the +partial of f respect to Y to find the + + align:start position:0% +partial of f respect to Y to find the + + + align:start position:0% +partial of f respect to Y to find the +partial of f respect to Y I have to + + align:start position:0% +partial of f respect to Y I have to + + + align:start position:0% +partial of f respect to Y I have to +differentiate this thing notice that Y + + align:start position:0% +differentiate this thing notice that Y + + + align:start position:0% +differentiate this thing notice that Y +is under the integral under the square + + align:start position:0% +is under the integral under the square + + + align:start position:0% +is under the integral under the square +root sign when I differentiate the + + align:start position:0% +root sign when I differentiate the + + + align:start position:0% +root sign when I differentiate the +square root the square root comes down + + align:start position:0% +square root the square root comes down + + + align:start position:0% +square root the square root comes down +into the denominator I can't allow a + + align:start position:0% +into the denominator I can't allow a + + + align:start position:0% +into the denominator I can't allow a +zero denominator so that tells tells me + + align:start position:0% +zero denominator so that tells tells me + + + align:start position:0% +zero denominator so that tells tells me +that not only must must y be less than + + align:start position:0% +that not only must must y be less than + + + align:start position:0% +that not only must must y be less than +or equal to 1/4 x^2 but rather y must + + align:start position:0% +or equal to 1/4 x^2 but rather y must + + + align:start position:0% +or equal to 1/4 x^2 but rather y must +be less than 1/4 x^2 because if y equal + + align:start position:0% +be less than 1/4 x^2 because if y equal + + + align:start position:0% +be less than 1/4 x^2 because if y equal +1/4 x^2 when this Factor comes down into + + align:start position:0% +1/4 x^2 when this Factor comes down into + + + align:start position:0% +1/4 x^2 when this Factor comes down into +the denominator I'm in trouble I have a + + align:start position:0% +the denominator I'm in trouble I have a + + + align:start position:0% +the denominator I'm in trouble I have a +zero denominator notice by the way the + + align:start position:0% +zero denominator notice by the way the + + + align:start position:0% +zero denominator notice by the way the +bad solution that we got in other words + + align:start position:0% +bad solution that we got in other words + + + align:start position:0% +bad solution that we got in other words +notice that where we got the two + + align:start position:0% +notice that where we got the two + + + align:start position:0% +notice that where we got the two +solutions occurred where y was equal to + + align:start position:0% +solutions occurred where y was equal to + + + align:start position:0% +solutions occurred where y was equal to +1/4 x squ and our key theorem doesn't + + align:start position:0% +1/4 x squ and our key theorem doesn't + + + align:start position:0% +1/4 x squ and our key theorem doesn't +apply in that case because notice that + + align:start position:0% +apply in that case because notice that + + + align:start position:0% +apply in that case because notice that +our key theorem says that the solution + + align:start position:0% +our key theorem says that the solution + + + align:start position:0% +our key theorem says that the solution +will be unique only in that region R + + align:start position:0% +will be unique only in that region R + + + align:start position:0% +will be unique only in that region R +where F and F suby are + + align:start position:0% +where F and F suby are + + + align:start position:0% +where F and F suby are +continuous you see notice that below the + + align:start position:0% +continuous you see notice that below the + + + align:start position:0% +continuous you see notice that below the +parabola F and F suby were continuous + + align:start position:0% +parabola F and F suby were continuous + + + align:start position:0% +parabola F and F suby were continuous +now these functions couldn't go bad in + + align:start position:0% +now these functions couldn't go bad in + + + align:start position:0% +now these functions couldn't go bad in +our problem consequently since we had + + align:start position:0% +our problem consequently since we had + + + align:start position:0% +our problem consequently since we had +one solution of the form y = CX - c^2 + + align:start position:0% +one solution of the form y = CX - c^2 + + + align:start position:0% +one solution of the form y = CX - c^2 +that passed through every point that + + align:start position:0% +that passed through every point that + + + align:start position:0% +that passed through every point that +below the parabola the fact that this + + align:start position:0% +below the parabola the fact that this + + + align:start position:0% +below the parabola the fact that this +theorem applies says there can't be any + + align:start position:0% +theorem applies says there can't be any + + + align:start position:0% +theorem applies says there can't be any +other solution because once you found + + align:start position:0% +other solution because once you found + + + align:start position:0% +other solution because once you found +one solution that's all there are that's + + align:start position:0% +one solution that's all there are that's + + + align:start position:0% +one solution that's all there are that's +exactly what you mean by unique see in + + align:start position:0% +exactly what you mean by unique see in + + + align:start position:0% +exactly what you mean by unique see in +other words if the solution is unique + + align:start position:0% +other words if the solution is unique + + + align:start position:0% +other words if the solution is unique +then we can talk about a general + + align:start position:0% +then we can talk about a general + + + align:start position:0% +then we can talk about a general +solution namely that solution that has + + align:start position:0% +solution namely that solution that has + + + align:start position:0% +solution namely that solution that has +one arbitrary consonant we can find what + + align:start position:0% +one arbitrary consonant we can find what + + + align:start position:0% +one arbitrary consonant we can find what +point it passes through by solving for + + align:start position:0% +point it passes through by solving for + + + align:start position:0% +point it passes through by solving for +the arbitrary constant and that's what + + align:start position:0% +the arbitrary constant and that's what + + + align:start position:0% +the arbitrary constant and that's what +we mean by a particular solution in fact + + align:start position:0% +we mean by a particular solution in fact + + + align:start position:0% +we mean by a particular solution in fact +let me just summarize that for you in + + align:start position:0% +let me just summarize that for you in + + + align:start position:0% +let me just summarize that for you in +terms of our two examples by a general + + align:start position:0% +terms of our two examples by a general + + + align:start position:0% +terms of our two examples by a general +solution you mean what you mean a + + align:start position:0% +solution you mean what you mean a + + + align:start position:0% +solution you mean what you mean a +solution that has one arbitrary constant + + align:start position:0% +solution that has one arbitrary constant + + + align:start position:0% +solution that has one arbitrary constant +such that through any point in your + + align:start position:0% +such that through any point in your + + + align:start position:0% +such that through any point in your +region you can get one and only one + + align:start position:0% +region you can get one and only one + + + align:start position:0% +region you can get one and only one +solution notice that the differential + + align:start position:0% +solution notice that the differential + + + align:start position:0% +solution notice that the differential +equation Dy DX = 2x has one solution y = + + align:start position:0% +equation Dy DX = 2x has one solution y = + + + align:start position:0% +equation Dy DX = 2x has one solution y = +x^2 + C one family of solutions all + + align:start position:0% +x^2 + C one family of solutions all + + + align:start position:0% +x^2 + C one family of solutions all +right that's the general solution notice + + align:start position:0% +right that's the general solution notice + + + align:start position:0% +right that's the general solution notice +that 2x you see if f ofx X Y is 2x f is + + align:start position:0% +that 2x you see if f ofx X Y is 2x f is + + + align:start position:0% +that 2x you see if f ofx X Y is 2x f is +certainly continuous the partial of f + + align:start position:0% +certainly continuous the partial of f + + + align:start position:0% +certainly continuous the partial of f +with respect to Y since f of x y is just + + align:start position:0% +with respect to Y since f of x y is just + + + align:start position:0% +with respect to Y since f of x y is just +2x is a function of X alone the partial + + align:start position:0% +2x is a function of X alone the partial + + + align:start position:0% +2x is a function of X alone the partial +respect to Y is zero which is certainly + + align:start position:0% +respect to Y is zero which is certainly + + + align:start position:0% +respect to Y is zero which is certainly +a continuous function in other words + + align:start position:0% +a continuous function in other words + + + align:start position:0% +a continuous function in other words +that's another way of seeing what we had + + align:start position:0% +that's another way of seeing what we had + + + align:start position:0% +that's another way of seeing what we had +in part one another way of looking at it + + align:start position:0% +in part one another way of looking at it + + + align:start position:0% +in part one another way of looking at it +that's in terms of our key theorem here + + align:start position:0% +that's in terms of our key theorem here + + + align:start position:0% +that's in terms of our key theorem here +why we have a unique family of solutions + + align:start position:0% +why we have a unique family of solutions + + + align:start position:0% +why we have a unique family of solutions +that in the whole XY plane 2X and its + + align:start position:0% +that in the whole XY plane 2X and its + + + align:start position:0% +that in the whole XY plane 2X and its +partial with respect to Y happen to be + + align:start position:0% +partial with respect to Y happen to be + + + align:start position:0% +partial with respect to Y happen to be +continuous on the other hand in example + + align:start position:0% +continuous on the other hand in example + + + align:start position:0% +continuous on the other hand in example +two the general solution was y = CX - + + align:start position:0% +two the general solution was y = CX - + + + align:start position:0% +two the general solution was y = CX - +c^2 provided that our region R was + + align:start position:0% +c^2 provided that our region R was + + + align:start position:0% +c^2 provided that our region R was +restricted to being what that we were + + align:start position:0% +restricted to being what that we were + + + align:start position:0% +restricted to being what that we were +below the parabola y = 1/4 x^2 by a + + align:start position:0% +below the parabola y = 1/4 x^2 by a + + + align:start position:0% +below the parabola y = 1/4 x^2 by a +particular solution we mean a solution + + align:start position:0% +particular solution we mean a solution + + + align:start position:0% +particular solution we mean a solution +that you can get to pass through a + + align:start position:0% +that you can get to pass through a + + + align:start position:0% +that you can get to pass through a +particular point in other words by + + align:start position:0% +particular point in other words by + + + align:start position:0% +particular point in other words by +arbitrarily specifying a value of the + + align:start position:0% +arbitrarily specifying a value of the + + + align:start position:0% +arbitrarily specifying a value of the +constant for example referring to + + align:start position:0% +constant for example referring to + + + align:start position:0% +constant for example referring to +example one again if I pick C to be 7 + + align:start position:0% +example one again if I pick C to be 7 + + + align:start position:0% +example one again if I pick C to be 7 +or- see y = x^2 + 7 y = x^2 - these are + + align:start position:0% +or- see y = x^2 + 7 y = x^2 - these are + + + align:start position:0% +or- see y = x^2 + 7 y = x^2 - these are +particular Solutions of the equation + + align:start position:0% +particular Solutions of the equation + + + align:start position:0% +particular Solutions of the equation +that we're talking about in particular + + align:start position:0% +that we're talking about in particular + + + align:start position:0% +that we're talking about in particular +what we're saying is if you want the + + align:start position:0% +what we're saying is if you want the + + + align:start position:0% +what we're saying is if you want the +particular solution see maybe I should + + align:start position:0% +particular solution see maybe I should + + + align:start position:0% +particular solution see maybe I should +emphasize that the particular solution + + align:start position:0% +emphasize that the particular solution + + + align:start position:0% +emphasize that the particular solution +that passes through the point x0 y0 your + + align:start position:0% +that passes through the point x0 y0 your + + + align:start position:0% +that passes through the point x0 y0 your +constant must be chosen to be y 0 - x 0^ + + align:start position:0% +constant must be chosen to be y 0 - x 0^ + + + align:start position:0% +constant must be chosen to be y 0 - x 0^ +2 in example two the general solution if + + align:start position:0% +2 in example two the general solution if + + + align:start position:0% +2 in example two the general solution if +we were the right if we were below the + + align:start position:0% +we were the right if we were below the + + + align:start position:0% +we were the right if we were below the +parabola was y = CX - c^ 2 in particular + + align:start position:0% +parabola was y = CX - c^ 2 in particular + + + align:start position:0% +parabola was y = CX - c^ 2 in particular +if I were to pick C to be 3 a particular + + align:start position:0% +if I were to pick C to be 3 a particular + + + align:start position:0% +if I were to pick C to be 3 a particular +solution would be what y = 3x - 9 or to + + align:start position:0% +solution would be what y = 3x - 9 or to + + + align:start position:0% +solution would be what y = 3x - 9 or to +do this more generally given the point + + align:start position:0% +do this more generally given the point + + + align:start position:0% +do this more generally given the point +x0 y0 the particular solution of Y = CX + + align:start position:0% +x0 y0 the particular solution of Y = CX + + + align:start position:0% +x0 y0 the particular solution of Y = CX +- c^ 2 which passes through this point + + align:start position:0% +- c^ 2 which passes through this point + + + align:start position:0% +- c^ 2 which passes through this point +is determined by C being this expression + + align:start position:0% +is determined by C being this expression + + + align:start position:0% +is determined by C being this expression +where the plus or minus sign is not + + align:start position:0% +where the plus or minus sign is not + + + align:start position:0% +where the plus or minus sign is not +really ambiguous here what we me meant + + align:start position:0% +really ambiguous here what we me meant + + + align:start position:0% +really ambiguous here what we me meant +was is that when we have the plus or + + align:start position:0% +was is that when we have the plus or + + + align:start position:0% +was is that when we have the plus or +minus sign we look at this as two + + align:start position:0% +minus sign we look at this as two + + + align:start position:0% +minus sign we look at this as two +separate problems finally we come to a + + align:start position:0% +separate problems finally we come to a + + + align:start position:0% +separate problems finally we come to a +third concept that's called a singular + + align:start position:0% +third concept that's called a singular + + + align:start position:0% +third concept that's called a singular +solution a singular solution occurs only + + align:start position:0% +solution a singular solution occurs only + + + align:start position:0% +solution a singular solution occurs only +when you're in a region where F or it's + + align:start position:0% +when you're in a region where F or it's + + + align:start position:0% +when you're in a region where F or it's +partial with respect to Y are not + + align:start position:0% +partial with respect to Y are not + + + align:start position:0% +partial with respect to Y are not +continuous for example there are no + + align:start position:0% +continuous for example there are no + + + align:start position:0% +continuous for example there are no +singular solutions to example one on the + + align:start position:0% +singular solutions to example one on the + + + align:start position:0% +singular solutions to example one on the +other hand a singular solution to + + align:start position:0% +other hand a singular solution to + + + align:start position:0% +other hand a singular solution to +example 2 was y = 1/4 x^2 why do I call + + align:start position:0% +example 2 was y = 1/4 x^2 why do I call + + + align:start position:0% +example 2 was y = 1/4 x^2 why do I call +it a singular a solution let me point + + align:start position:0% +it a singular a solution let me point + + + align:start position:0% +it a singular a solution let me point +out that you there is no way of getting + + align:start position:0% +out that you there is no way of getting + + + align:start position:0% +out that you there is no way of getting +y = 1/4 + + align:start position:0% +y = 1/4 + + + align:start position:0% +y = 1/4 +x^2 by judiciously choosing the constant + + align:start position:0% +x^2 by judiciously choosing the constant + + + align:start position:0% +x^2 by judiciously choosing the constant +c as long as C is a constant observe + + align:start position:0% +c as long as C is a constant observe + + + align:start position:0% +c as long as C is a constant observe +that for every choice of c y = CX - c^2 + + align:start position:0% +that for every choice of c y = CX - c^2 + + + align:start position:0% +that for every choice of c y = CX - c^2 +is a straight line in particular the + + align:start position:0% +is a straight line in particular the + + + align:start position:0% +is a straight line in particular the +straight line whose slope is C and Whose + + align:start position:0% +straight line whose slope is C and Whose + + + align:start position:0% +straight line whose slope is C and Whose +y intercept is - c^ 2 in other words I + + align:start position:0% +y intercept is - c^ 2 in other words I + + + align:start position:0% +y intercept is - c^ 2 in other words I +cannot get the curve y = 1/4 x^2 by + + align:start position:0% +cannot get the curve y = 1/4 x^2 by + + + align:start position:0% +cannot get the curve y = 1/4 x^2 by +specifying a constant here that's why + + align:start position:0% +specifying a constant here that's why + + + align:start position:0% +specifying a constant here that's why +it's called a singular solution it it + + align:start position:0% +it's called a singular solution it it + + + align:start position:0% +it's called a singular solution it it +cannot be obtained from the general + + align:start position:0% +cannot be obtained from the general + + + align:start position:0% +cannot be obtained from the general +solution but notice that that singular + + align:start position:0% +solution but notice that that singular + + + align:start position:0% +solution but notice that that singular +solution only existed because we + + align:start position:0% +solution only existed because we + + + align:start position:0% +solution only existed because we +violated the condition that our region B + + align:start position:0% +violated the condition that our region B + + + align:start position:0% +violated the condition that our region B +below the parabola in other words once + + align:start position:0% +below the parabola in other words once + + + align:start position:0% +below the parabola in other words once +we get outside of the region where F and + + align:start position:0% +we get outside of the region where F and + + + align:start position:0% +we get outside of the region where F and +F suby were continuous then mongral type + + align:start position:0% +F suby were continuous then mongral type + + + align:start position:0% +F suby were continuous then mongral type +solutions could have snuck in and those + + align:start position:0% +solutions could have snuck in and those + + + align:start position:0% +solutions could have snuck in and those +are what are called singular Solutions + + align:start position:0% +are what are called singular Solutions + + + align:start position:0% +are what are called singular Solutions +but I'll talk about those more uh in the + + align:start position:0% +but I'll talk about those more uh in the + + + align:start position:0% +but I'll talk about those more uh in the +exercise + + align:start position:0% +exercise + + + align:start position:0% +exercise +what I thought I would like to do for + + align:start position:0% +what I thought I would like to do for + + + align:start position:0% +what I thought I would like to do for +the remainder of this + + align:start position:0% +the remainder of this + + + align:start position:0% +the remainder of this +lecture is to talk specifically about + + align:start position:0% +lecture is to talk specifically about + + + align:start position:0% +lecture is to talk specifically about +what the textbook is all about and uh + + align:start position:0% +what the textbook is all about and uh + + + align:start position:0% +what the textbook is all about and uh +what we'll be dealing with for the next + + align:start position:0% +what we'll be dealing with for the next + + + align:start position:0% +what we'll be dealing with for the next +few lessons you see the next few units + + align:start position:0% +few lessons you see the next few units + + + align:start position:0% +few lessons you see the next few units +will not have any lectures this is the + + align:start position:0% +will not have any lectures this is the + + + align:start position:0% +will not have any lectures this is the +lecture that will launch you into + + align:start position:0% +lecture that will launch you into + + + align:start position:0% +lecture that will launch you into +solving first order first deegree + + align:start position:0% +solving first order first deegree + + + align:start position:0% +solving first order first deegree +equations from this point on until we + + align:start position:0% +equations from this point on until we + + + align:start position:0% +equations from this point on until we +get to uh second order equations there + + align:start position:0% +get to uh second order equations there + + + align:start position:0% +get to uh second order equations there +will be no lectures simply reading a + + align:start position:0% +will be no lectures simply reading a + + + align:start position:0% +will be no lectures simply reading a +assignments in the text and learning + + align:start position:0% +assignments in the text and learning + + + align:start position:0% +assignments in the text and learning +exercises where I'll try to give you the + + align:start position:0% +exercises where I'll try to give you the + + + align:start position:0% +exercises where I'll try to give you the +so-called cookbook part of differential + + align:start position:0% +so-called cookbook part of differential + + + align:start position:0% +so-called cookbook part of differential +equations but I thought that to lead + + align:start position:0% +equations but I thought that to lead + + + align:start position:0% +equations but I thought that to lead +into that what I thought I wanted to + + align:start position:0% +into that what I thought I wanted to + + + align:start position:0% +into that what I thought I wanted to +bring out was this let's suppose that we + + align:start position:0% +bring out was this let's suppose that we + + + align:start position:0% +bring out was this let's suppose that we +restrict our attention to not only first + + align:start position:0% +restrict our attention to not only first + + + align:start position:0% +restrict our attention to not only first +order equations but first deegree + + align:start position:0% +order equations but first deegree + + + align:start position:0% +order equations but first deegree +equations in other words not only does + + align:start position:0% +equations in other words not only does + + + align:start position:0% +equations in other words not only does +the only derivative that appears is the + + align:start position:0% +the only derivative that appears is the + + + align:start position:0% +the only derivative that appears is the +be the first derivative but it also + + align:start position:0% +be the first derivative but it also + + + align:start position:0% +be the first derivative but it also +happens to appear only to the first + + align:start position:0% +happens to appear only to the first + + + align:start position:0% +happens to appear only to the first +Power all right notice that in that + + align:start position:0% +Power all right notice that in that + + + align:start position:0% +Power all right notice that in that +situation as I look at every term in my + + align:start position:0% +situation as I look at every term in my + + + align:start position:0% +situation as I look at every term in my +differential equation they fall into two + + align:start position:0% +differential equation they fall into two + + + align:start position:0% +differential equation they fall into two +types there'll be a term in which dydx + + align:start position:0% +types there'll be a term in which dydx + + + align:start position:0% +types there'll be a term in which dydx +is a factor or a term where dydx is not + + align:start position:0% +is a factor or a term where dydx is not + + + align:start position:0% +is a factor or a term where dydx is not +a factor what I can therefore do is + + align:start position:0% +a factor what I can therefore do is + + + align:start position:0% +a factor what I can therefore do is +collect all the terms which have Dy DX + + align:start position:0% +collect all the terms which have Dy DX + + + align:start position:0% +collect all the terms which have Dy DX +as a factor and factor out Dy DX so I + + align:start position:0% +as a factor and factor out Dy DX so I + + + align:start position:0% +as a factor and factor out Dy DX so I +have a term of the form what some + + align:start position:0% +have a term of the form what some + + + align:start position:0% +have a term of the form what some +function n of X and Y * Dy DX + + align:start position:0% +function n of X and Y * Dy DX + + + align:start position:0% +function n of X and Y * Dy DX +plus what a bunch of terms involving + + align:start position:0% +plus what a bunch of terms involving + + + align:start position:0% +plus what a bunch of terms involving +only X and Y which have no dydx in them + + align:start position:0% +only X and Y which have no dydx in them + + + align:start position:0% +only X and Y which have no dydx in them +equals zero I know words this is the + + align:start position:0% +equals zero I know words this is the + + + align:start position:0% +equals zero I know words this is the +most general form of my first order + + align:start position:0% +most general form of my first order + + + align:start position:0% +most general form of my first order +first degree equation if I now treat + + align:start position:0% +first degree equation if I now treat + + + align:start position:0% +first degree equation if I now treat +these as differentials and multiply + + align:start position:0% +these as differentials and multiply + + + align:start position:0% +these as differentials and multiply +through by DX notice that I'm back to + + align:start position:0% +through by DX notice that I'm back to + + + align:start position:0% +through by DX notice that I'm back to +the standard differential equation form + + align:start position:0% +the standard differential equation form + + + align:start position:0% +the standard differential equation form +that we talked about in fact I'll bring + + align:start position:0% +that we talked about in fact I'll bring + + + align:start position:0% +that we talked about in fact I'll bring +this up again in a moment in block three + + align:start position:0% +this up again in a moment in block three + + + align:start position:0% +this up again in a moment in block three +when we introduced exact differentials + + align:start position:0% +when we introduced exact differentials + + + align:start position:0% +when we introduced exact differentials +namely I have an equation of what form M + + align:start position:0% +namely I have an equation of what form M + + + align:start position:0% +namely I have an equation of what form M +DX plus n Dy y equal 0 by the way to + + align:start position:0% +DX plus n Dy y equal 0 by the way to + + + align:start position:0% +DX plus n Dy y equal 0 by the way to +correlate this with our key theorem + + align:start position:0% +correlate this with our key theorem + + + align:start position:0% +correlate this with our key theorem +notice that from here I could have + + align:start position:0% +notice that from here I could have + + + align:start position:0% +notice that from here I could have +written that Dy DX was minus M of XY + + align:start position:0% +written that Dy DX was minus M of XY + + + align:start position:0% +written that Dy DX was minus M of XY +Over N of XY and that's the f ofx y that + + align:start position:0% +Over N of XY and that's the f ofx y that + + + align:start position:0% +Over N of XY and that's the f ofx y that +I'm talking about in our key theorem + + align:start position:0% +I'm talking about in our key theorem + + + align:start position:0% +I'm talking about in our key theorem +that we talked about earlier see in + + align:start position:0% +that we talked about earlier see in + + + align:start position:0% +that we talked about earlier see in +other words f ofx y is the right hand + + align:start position:0% +other words f ofx y is the right hand + + + align:start position:0% +other words f ofx y is the right hand +side of the equation when the left hand + + align:start position:0% +side of the equation when the left hand + + + align:start position:0% +side of the equation when the left hand +side is specifically dydx so in other + + align:start position:0% +side is specifically dydx so in other + + + align:start position:0% +side is specifically dydx so in other +words what I'm guaranteed of is this as + + align:start position:0% +words what I'm guaranteed of is this as + + + align:start position:0% +words what I'm guaranteed of is this as +long as this function on the right hand + + align:start position:0% +long as this function on the right hand + + + align:start position:0% +long as this function on the right hand +side is continuous and it's partial with + + align:start position:0% +side is continuous and it's partial with + + + align:start position:0% +side is continuous and it's partial with +respect to Y is continuous I'm + + align:start position:0% +respect to Y is continuous I'm + + + align:start position:0% +respect to Y is continuous I'm +guaranteed that this equation has a + + align:start position:0% +guaranteed that this equation has a + + + align:start position:0% +guaranteed that this equation has a +general solution in particular if m&n + + align:start position:0% +general solution in particular if m&n + + + align:start position:0% +general solution in particular if m&n +happen to be continuously differentiable + + align:start position:0% +happen to be continuously differentiable + + + align:start position:0% +happen to be continuously differentiable +functions the general solution will + + align:start position:0% +functions the general solution will + + + align:start position:0% +functions the general solution will +exist provided only that n and its + + align:start position:0% +exist provided only that n and its + + + align:start position:0% +exist provided only that n and its +partial with respect to Y are not zero + + align:start position:0% +partial with respect to Y are not zero + + + align:start position:0% +partial with respect to Y are not zero +because after all to differentiate this + + align:start position:0% +because after all to differentiate this + + + align:start position:0% +because after all to differentiate this +with respect to Y this is a + + align:start position:0% +with respect to Y this is a + + + align:start position:0% +with respect to Y this is a +quotient and the only place that I'm + + align:start position:0% +quotient and the only place that I'm + + + align:start position:0% +quotient and the only place that I'm +going to be in trouble is that the + + align:start position:0% +going to be in trouble is that the + + + align:start position:0% +going to be in trouble is that the +square of the denominator appears when I + + align:start position:0% +square of the denominator appears when I + + + align:start position:0% +square of the denominator appears when I +use the quotient rule so I have to be + + align:start position:0% +use the quotient rule so I have to be + + + align:start position:0% +use the quotient rule so I have to be +careful where where + + align:start position:0% +careful where where + + + align:start position:0% +careful where where +either the partial event respect to y or + + align:start position:0% +either the partial event respect to y or + + + align:start position:0% +either the partial event respect to y or +n itself happen to be zero but if that + + align:start position:0% +n itself happen to be zero but if that + + + align:start position:0% +n itself happen to be zero but if that +doesn't happen it means there is a + + align:start position:0% +doesn't happen it means there is a + + + align:start position:0% +doesn't happen it means there is a +general solution now you may remember I + + align:start position:0% +general solution now you may remember I + + + align:start position:0% +general solution now you may remember I +back in block three we said you know if + + align:start position:0% +back in block three we said you know if + + + align:start position:0% +back in block three we said you know if +this differential happens to be exact in + + align:start position:0% +this differential happens to be exact in + + + align:start position:0% +this differential happens to be exact in +other words if there happens to be a fun + + align:start position:0% +other words if there happens to be a fun + + + align:start position:0% +other words if there happens to be a fun +function W such that DW is MDX plus ndy + + align:start position:0% +function W such that DW is MDX plus ndy + + + align:start position:0% +function W such that DW is MDX plus ndy +then it's trivial to solve this equation + + align:start position:0% +then it's trivial to solve this equation + + + align:start position:0% +then it's trivial to solve this equation +in particular for what we mean by an + + align:start position:0% +in particular for what we mean by an + + + align:start position:0% +in particular for what we mean by an +exact differential equation is simply + + align:start position:0% +exact differential equation is simply + + + align:start position:0% +exact differential equation is simply +this if MDX plus mdy is exact then we + + align:start position:0% +this if MDX plus mdy is exact then we + + + align:start position:0% +this if MDX plus mdy is exact then we +call the equation MDX plus ndy equal 0 + + align:start position:0% +call the equation MDX plus ndy equal 0 + + + align:start position:0% +call the equation MDX plus ndy equal 0 +an exact differential equation and the + + align:start position:0% +an exact differential equation and the + + + align:start position:0% +an exact differential equation and the +solution of that equation is simply f + + align:start position:0% +solution of that equation is simply f + + + align:start position:0% +solution of that equation is simply f +ofx yal c where f is any fun function + + align:start position:0% +ofx yal c where f is any fun function + + + align:start position:0% +ofx yal c where f is any fun function +such that DF is MDX plus ndy and we're + + align:start position:0% +such that DF is MDX plus ndy and we're + + + align:start position:0% +such that DF is MDX plus ndy and we're +sure that such a function f exists by + + align:start position:0% +sure that such a function f exists by + + + align:start position:0% +sure that such a function f exists by +definition of MDX plus n Dy being exact + + align:start position:0% +definition of MDX plus n Dy being exact + + + align:start position:0% +definition of MDX plus n Dy being exact +see by way of example suppose I were + + align:start position:0% +see by way of example suppose I were + + + align:start position:0% +see by way of example suppose I were +given the equation ydx plus XD y equal 0 + + align:start position:0% +given the equation ydx plus XD y equal 0 + + + align:start position:0% +given the equation ydx plus XD y equal 0 +forget about the fact that I could have + + align:start position:0% +forget about the fact that I could have + + + align:start position:0% +forget about the fact that I could have +solved this easier by just separating + + align:start position:0% +solved this easier by just separating + + + align:start position:0% +solved this easier by just separating +the variables notice by way of + + align:start position:0% +the variables notice by way of + + + align:start position:0% +the variables notice by way of +illustration that the left hand side + + align:start position:0% +illustration that the left hand side + + + align:start position:0% +illustration that the left hand side +here is just the differential of X X Y + + align:start position:0% +here is just the differential of X X Y + + + align:start position:0% +here is just the differential of X X Y +in other words y DX plus x d y equal 0 + + align:start position:0% +in other words y DX plus x d y equal 0 + + + align:start position:0% +in other words y DX plus x d y equal 0 +says that the differential of XY is zero + + align:start position:0% +says that the differential of XY is zero + + + align:start position:0% +says that the differential of XY is zero +where Y is implicitly now some function + + align:start position:0% +where Y is implicitly now some function + + + align:start position:0% +where Y is implicitly now some function +of X now if the differential of some + + align:start position:0% +of X now if the differential of some + + + align:start position:0% +of X now if the differential of some +function of X is zero then that function + + align:start position:0% +function of X is zero then that function + + + align:start position:0% +function of X is zero then that function +itself must be a constant consequently + + align:start position:0% +itself must be a constant consequently + + + align:start position:0% +itself must be a constant consequently +XY equals a constant is a solution of + + align:start position:0% +XY equals a constant is a solution of + + + align:start position:0% +XY equals a constant is a solution of +this differential + + align:start position:0% +this differential + + + align:start position:0% +this differential +equation the problem that comes up is + + align:start position:0% +equation the problem that comes up is + + + align:start position:0% +equation the problem that comes up is +wouldn't it be nice that's not the + + align:start position:0% +wouldn't it be nice that's not the + + + align:start position:0% +wouldn't it be nice that's not the +problem the question is wouldn't it be + + align:start position:0% +problem the question is wouldn't it be + + + align:start position:0% +problem the question is wouldn't it be +nice if every first order first deegree + + align:start position:0% +nice if every first order first deegree + + + align:start position:0% +nice if every first order first deegree +differential equation happened to be + + align:start position:0% +differential equation happened to be + + + align:start position:0% +differential equation happened to be +exact see if if it were we'd be all done + + align:start position:0% +exact see if if it were we'd be all done + + + align:start position:0% +exact see if if it were we'd be all done +we talked about that as I say back in + + align:start position:0% +we talked about that as I say back in + + + align:start position:0% +we talked about that as I say back in +block three If This Were exact this is + + align:start position:0% +block three If This Were exact this is + + + align:start position:0% +block three If This Were exact this is +how we solve it but we also saw in block + + align:start position:0% +how we solve it but we also saw in block + + + align:start position:0% +how we solve it but we also saw in block +three that it's very uh very unique if + + align:start position:0% +three that it's very uh very unique if + + + align:start position:0% +three that it's very uh very unique if +the thing happens to be exact see in + + align:start position:0% +the thing happens to be exact see in + + + align:start position:0% +the thing happens to be exact see in +general the differential won't be exact + + align:start position:0% +general the differential won't be exact + + + align:start position:0% +general the differential won't be exact +and that's why I look now at non-exact + + align:start position:0% +and that's why I look now at non-exact + + + align:start position:0% +and that's why I look now at non-exact +equations see non-exact means what not + + align:start position:0% +equations see non-exact means what not + + + align:start position:0% +equations see non-exact means what not +that the equation is isn't exact but the + + align:start position:0% +that the equation is isn't exact but the + + + align:start position:0% +that the equation is isn't exact but the +differential isn't an exact differential + + align:start position:0% +differential isn't an exact differential + + + align:start position:0% +differential isn't an exact differential +look at ydx - xdy the partial of Y with + + align:start position:0% +look at ydx - xdy the partial of Y with + + + align:start position:0% +look at ydx - xdy the partial of Y with +respect to Y is 1 the partial of Min - x + + align:start position:0% +respect to Y is 1 the partial of Min - x + + + align:start position:0% +respect to Y is 1 the partial of Min - x +with respect to X is minus one this + + align:start position:0% +with respect to X is minus one this + + + align:start position:0% +with respect to X is minus one this +thing is not exact consequently this is + + align:start position:0% +thing is not exact consequently this is + + + align:start position:0% +thing is not exact consequently this is +not the differential of any particular + + align:start position:0% +not the differential of any particular + + + align:start position:0% +not the differential of any particular +function let me show you a little trick + + align:start position:0% +function let me show you a little trick + + + align:start position:0% +function let me show you a little trick +over here though this sort of suggests + + align:start position:0% +over here though this sort of suggests + + + align:start position:0% +over here though this sort of suggests +the quotient rule see the denominator + + align:start position:0% +the quotient rule see the denominator + + + align:start position:0% +the quotient rule see the denominator +times the differential of the numerator + + align:start position:0% +times the differential of the numerator + + + align:start position:0% +times the differential of the numerator +minus the numerator times the + + align:start position:0% +minus the numerator times the + + + align:start position:0% +minus the numerator times the +differential of the denominator except + + align:start position:0% +differential of the denominator except + + + align:start position:0% +differential of the denominator except +there should be a denominator here + + align:start position:0% +there should be a denominator here + + + align:start position:0% +there should be a denominator here +appearing as y squ you see and what I do + + align:start position:0% +appearing as y squ you see and what I do + + + align:start position:0% +appearing as y squ you see and what I do +is I say okay why don't I just divide + + align:start position:0% +is I say okay why don't I just divide + + + align:start position:0% +is I say okay why don't I just divide +both sides of this equation by + + align:start position:0% +both sides of this equation by + + + align:start position:0% +both sides of this equation by +y^2 if I do that and invoke the rule + + align:start position:0% +y^2 if I do that and invoke the rule + + + align:start position:0% +y^2 if I do that and invoke the rule +that equals / equals are equal being + + align:start position:0% +that equals / equals are equal being + + + align:start position:0% +that equals / equals are equal being +careful to remember that I'm in trouble + + align:start position:0% +careful to remember that I'm in trouble + + + align:start position:0% +careful to remember that I'm in trouble +when y equals z i got to keep that in + + align:start position:0% +when y equals z i got to keep that in + + + align:start position:0% +when y equals z i got to keep that in +the back of my mind remembering that Y + + align:start position:0% +the back of my mind remembering that Y + + + align:start position:0% +the back of my mind remembering that Y +is zero at any rate this equation + + align:start position:0% +is zero at any rate this equation + + + align:start position:0% +is zero at any rate this equation +transforms into y DX - xdy over y^2 = 0 + + align:start position:0% +transforms into y DX - xdy over y^2 = 0 + + + align:start position:0% +transforms into y DX - xdy over y^2 = 0 +the left hand side this this + + align:start position:0% +the left hand side this this + + + align:start position:0% +the left hand side this this +differential is now exact believe it or + + align:start position:0% +differential is now exact believe it or + + + align:start position:0% +differential is now exact believe it or +not it wasn't exact to begin with but by + + align:start position:0% +not it wasn't exact to begin with but by + + + align:start position:0% +not it wasn't exact to begin with but by +dividing it by y^2 it became exact in + + align:start position:0% +dividing it by y^2 it became exact in + + + align:start position:0% +dividing it by y^2 it became exact in +fact the left hand side is not the + + align:start position:0% +fact the left hand side is not the + + + align:start position:0% +fact the left hand side is not the +differential of X over Y in other words + + align:start position:0% +differential of X over Y in other words + + + align:start position:0% +differential of X over Y in other words +the differential of X over Y is zero + + align:start position:0% +the differential of X over Y is zero + + + align:start position:0% +the differential of X over Y is zero +therefore X over Y is a constant or in + + align:start position:0% +therefore X over Y is a constant or in + + + align:start position:0% +therefore X over Y is a constant or in +particular Y is some constant time x by + + align:start position:0% +particular Y is some constant time x by + + + align:start position:0% +particular Y is some constant time x by +the way remembering that y had to be + + align:start position:0% +the way remembering that y had to be + + + align:start position:0% +the way remembering that y had to be +unequal to zero for this to be true + + align:start position:0% +unequal to zero for this to be true + + + align:start position:0% +unequal to zero for this to be true +notice that we have to check y equals 0 + + align:start position:0% +notice that we have to check y equals 0 + + + align:start position:0% +notice that we have to check y equals 0 +separately notice by the way that y + + align:start position:0% +separately notice by the way that y + + + align:start position:0% +separately notice by the way that y +equals 0 is a particular solution of + + align:start position:0% +equals 0 is a particular solution of + + + align:start position:0% +equals 0 is a particular solution of +this equation obtained by choosing c + + align:start position:0% +this equation obtained by choosing c + + + align:start position:0% +this equation obtained by choosing c +equal to 0 so y equals 0 gives us no + + align:start position:0% +equal to 0 so y equals 0 gives us no + + + align:start position:0% +equal to 0 so y equals 0 gives us no +great hot here but the thing I'm leading + + align:start position:0% +great hot here but the thing I'm leading + + + align:start position:0% +great hot here but the thing I'm leading +up to and I'm sorry for all these asides + + align:start position:0% +up to and I'm sorry for all these asides + + + align:start position:0% +up to and I'm sorry for all these asides +but what I'm leading up to is something + + align:start position:0% +but what I'm leading up to is something + + + align:start position:0% +but what I'm leading up to is something +called an integrating factor and that's + + align:start position:0% +called an integrating factor and that's + + + align:start position:0% +called an integrating factor and that's +what we just used over here what we say + + align:start position:0% +what we just used over here what we say + + + align:start position:0% +what we just used over here what we say +is if MDX plus mdy is not zero equals + + align:start position:0% +is if MDX plus mdy is not zero equals + + + align:start position:0% +is if MDX plus mdy is not zero equals +zero is not exact make it exact what + + align:start position:0% +zero is not exact make it exact what + + + align:start position:0% +zero is not exact make it exact what +does that mean find a function U of X + + align:start position:0% +does that mean find a function U of X + + + align:start position:0% +does that mean find a function U of X +and Y such that when I multiply or + + align:start position:0% +and Y such that when I multiply or + + + align:start position:0% +and Y such that when I multiply or +divide makes no difference both sides of + + align:start position:0% +divide makes no difference both sides of + + + align:start position:0% +divide makes no difference both sides of +this equation byy it the new equation + + align:start position:0% +this equation byy it the new equation + + + align:start position:0% +this equation byy it the new equation +which you + + align:start position:0% +which you + + + align:start position:0% +which you +has the same solution set as this one + + align:start position:0% +has the same solution set as this one + + + align:start position:0% +has the same solution set as this one +see in other + + align:start position:0% +see in other + + + align:start position:0% +see in other +words a solution something is a solution + + align:start position:0% +words a solution something is a solution + + + align:start position:0% +words a solution something is a solution +of this equation if and only if it's a + + align:start position:0% +of this equation if and only if it's a + + + align:start position:0% +of this equation if and only if it's a +solution of this equation see it's + + align:start position:0% +solution of this equation see it's + + + align:start position:0% +solution of this equation see it's +equals multiplied by equals or equal + + align:start position:0% +equals multiplied by equals or equal + + + align:start position:0% +equals multiplied by equals or equal +what if this is exact see that's + + align:start position:0% +what if this is exact see that's + + + align:start position:0% +what if this is exact see that's +precisely what we did up here y DX - xdy + + align:start position:0% +precisely what we did up here y DX - xdy + + + align:start position:0% +precisely what we did up here y DX - xdy +was not exact the U of XY in that case + + align:start position:0% +was not exact the U of XY in that case + + + align:start position:0% +was not exact the U of XY in that case +was just 1 over y^2 we multiplied both + + align:start position:0% +was just 1 over y^2 we multiplied both + + + align:start position:0% +was just 1 over y^2 we multiplied both +sides of the equation by 1 over y^2 and + + align:start position:0% +sides of the equation by 1 over y^2 and + + + align:start position:0% +sides of the equation by 1 over y^2 and +made this exact the problem is this + + align:start position:0% +made this exact the problem is this + + + align:start position:0% +made this exact the problem is this +though + + align:start position:0% +though + + + align:start position:0% +though +it turns out theoretically that if an + + align:start position:0% +it turns out theoretically that if an + + + align:start position:0% +it turns out theoretically that if an +equation of first order first degree is + + align:start position:0% +equation of first order first degree is + + + align:start position:0% +equation of first order first degree is +not exact there is an integrating Factor + + align:start position:0% +not exact there is an integrating Factor + + + align:start position:0% +not exact there is an integrating Factor +another words something that you can + + align:start position:0% +another words something that you can + + + align:start position:0% +another words something that you can +multiply it by to make it exact the + + align:start position:0% +multiply it by to make it exact the + + + align:start position:0% +multiply it by to make it exact the +problem is that in real life that factor + + align:start position:0% +problem is that in real life that factor + + + align:start position:0% +problem is that in real life that factor +is harder to find than the solution of + + align:start position:0% +is harder to find than the solution of + + + align:start position:0% +is harder to find than the solution of +the original equation in most cases + + align:start position:0% +the original equation in most cases + + + align:start position:0% +the original equation in most cases +namely how would I find a u such that + + align:start position:0% +namely how would I find a u such that + + + align:start position:0% +namely how would I find a u such that +this was exact remember the condition + + align:start position:0% +this was exact remember the condition + + + align:start position:0% +this was exact remember the condition +for exactness is that the partial of + + align:start position:0% +for exactness is that the partial of + + + align:start position:0% +for exactness is that the partial of +this with respect to Y has to equal the + + align:start position:0% +this with respect to Y has to equal the + + + align:start position:0% +this with respect to Y has to equal the +partial of this with respect to X + + align:start position:0% +partial of this with respect to X + + + align:start position:0% +partial of this with respect to X +remembering that U is a function of X + + align:start position:0% +remembering that U is a function of X + + + align:start position:0% +remembering that U is a function of X +and Y I have to use the product rule + + align:start position:0% +and Y I have to use the product rule + + + align:start position:0% +and Y I have to use the product rule +over here I get U * the partial of n + + align:start position:0% +over here I get U * the partial of n + + + align:start position:0% +over here I get U * the partial of n +respect to Y plus the partial of U + + align:start position:0% +respect to Y plus the partial of U + + + align:start position:0% +respect to Y plus the partial of U +respect to y * n equals U * the partial + + align:start position:0% +respect to y * n equals U * the partial + + + align:start position:0% +respect to y * n equals U * the partial +of n respect to X plus the parti respect + + align:start position:0% +of n respect to X plus the parti respect + + + align:start position:0% +of n respect to X plus the parti respect +to x * n and look at this equation I'm + + align:start position:0% +to x * n and look at this equation I'm + + + align:start position:0% +to x * n and look at this equation I'm +trying to solve this for you and notice + + align:start position:0% +trying to solve this for you and notice + + + align:start position:0% +trying to solve this for you and notice +that this is still a differential + + align:start position:0% +that this is still a differential + + + align:start position:0% +that this is still a differential +equation but it involves even partial + + align:start position:0% +equation but it involves even partial + + + align:start position:0% +equation but it involves even partial +derivatives in other words to solve this + + align:start position:0% +derivatives in other words to solve this + + + align:start position:0% +derivatives in other words to solve this +equation involves having to solve a + + align:start position:0% +equation involves having to solve a + + + align:start position:0% +equation involves having to solve a +partial differential equation which is + + align:start position:0% +partial differential equation which is + + + align:start position:0% +partial differential equation which is +even harder to do than the equation that + + align:start position:0% +even harder to do than the equation that + + + align:start position:0% +even harder to do than the equation that +we're trying to solve now well at any + + align:start position:0% +we're trying to solve now well at any + + + align:start position:0% +we're trying to solve now well at any +rate let me show you now in summary why + + align:start position:0% +rate let me show you now in summary why + + + align:start position:0% +rate let me show you now in summary why +people refer to differential equations + + align:start position:0% +people refer to differential equations + + + align:start position:0% +people refer to differential equations +as a cookbook course philosophically + + align:start position:0% +as a cookbook course philosophically + + + align:start position:0% +as a cookbook course philosophically +there's nothing to solving first order + + align:start position:0% +there's nothing to solving first order + + + align:start position:0% +there's nothing to solving first order +first-degree differential equations + + align:start position:0% +first-degree differential equations + + + align:start position:0% +first-degree differential equations +namely look at the differential if it's + + align:start position:0% +namely look at the differential if it's + + + align:start position:0% +namely look at the differential if it's +exact bang you just integrate it + + align:start position:0% +exact bang you just integrate it + + + align:start position:0% +exact bang you just integrate it +directly find the W such that DW is MDX + + align:start position:0% +directly find the W such that DW is MDX + + + align:start position:0% +directly find the W such that DW is MDX +Plus mdy y then W equals a constant as a + + align:start position:0% +Plus mdy y then W equals a constant as a + + + align:start position:0% +Plus mdy y then W equals a constant as a +solution if it's not exact find an + + align:start position:0% +solution if it's not exact find an + + + align:start position:0% +solution if it's not exact find an +integrating Factor Make It exact the + + align:start position:0% +integrating Factor Make It exact the + + + align:start position:0% +integrating Factor Make It exact the +trouble is that in real life given a + + align:start position:0% +trouble is that in real life given a + + + align:start position:0% +trouble is that in real life given a +particular equation it's very very + + align:start position:0% +particular equation it's very very + + + align:start position:0% +particular equation it's very very +difficult to find the integrating Factor + + align:start position:0% +difficult to find the integrating Factor + + + align:start position:0% +difficult to find the integrating Factor +consequently what one does is one + + align:start position:0% +consequently what one does is one + + + align:start position:0% +consequently what one does is one +categorizes various types of first order + + align:start position:0% +categorizes various types of first order + + + align:start position:0% +categorizes various types of first order +first-degree differential equations + + align:start position:0% +first-degree differential equations + + + align:start position:0% +first-degree differential equations +according to their structure and shows + + align:start position:0% +according to their structure and shows + + + align:start position:0% +according to their structure and shows +little tricks for solving special kinds + + align:start position:0% +little tricks for solving special kinds + + + align:start position:0% +little tricks for solving special kinds +of equations speci types where we can + + align:start position:0% +of equations speci types where we can + + + align:start position:0% +of equations speci types where we can +cut through the red tape and either find + + align:start position:0% +cut through the red tape and either find + + + align:start position:0% +cut through the red tape and either find +our integrating factor or a direct + + align:start position:0% +our integrating factor or a direct + + + align:start position:0% +our integrating factor or a direct +solution rather uh easily at any rate + + align:start position:0% +solution rather uh easily at any rate + + + align:start position:0% +solution rather uh easily at any rate +that part is taken care of magnificently + + align:start position:0% +that part is taken care of magnificently + + + align:start position:0% +that part is taken care of magnificently +in the textbook and coupled with my + + align:start position:0% +in the textbook and coupled with my + + + align:start position:0% +in the textbook and coupled with my +unique learning exercises you will get + + align:start position:0% +unique learning exercises you will get + + + align:start position:0% +unique learning exercises you will get +an excellent amount of drill in how to + + align:start position:0% +an excellent amount of drill in how to + + + align:start position:0% +an excellent amount of drill in how to +do the mechanics but what I wanted this + + align:start position:0% +do the mechanics but what I wanted this + + + align:start position:0% +do the mechanics but what I wanted this +lecture to do was to have you at least + + align:start position:0% +lecture to do was to have you at least + + + align:start position:0% +lecture to do was to have you at least +understand for sure what you meant by a + + align:start position:0% +understand for sure what you meant by a + + + align:start position:0% +understand for sure what you meant by a +solution to an equation what you meant + + align:start position:0% +solution to an equation what you meant + + + align:start position:0% +solution to an equation what you meant +by a en solution a particular solution a + + align:start position:0% +by a en solution a particular solution a + + + align:start position:0% +by a en solution a particular solution a +singular solution Etc at any rate then + + align:start position:0% +singular solution Etc at any rate then + + + align:start position:0% +singular solution Etc at any rate then +until we meet again for second and + + align:start position:0% +until we meet again for second and + + + align:start position:0% +until we meet again for second and +higher order differential equations + + align:start position:0% +higher order differential equations + + + align:start position:0% +higher order differential equations +let's just say soong for + + align:start position:0% +let's just say soong for + + + align:start position:0% +let's just say soong for +now funding for the publication of this + + align:start position:0% +now funding for the publication of this + + + align:start position:0% +now funding for the publication of this +video was provided by the Gabriella and + + align:start position:0% +video was provided by the Gabriella and + + + align:start position:0% +video was provided by the Gabriella and +Paul rosenbom + + align:start position:0% +Paul rosenbom + + + align:start position:0% +Paul rosenbom +foundation help ocw continue to provide + + align:start position:0% +foundation help ocw continue to provide + + + align:start position:0% +foundation help ocw continue to provide +free and open access to MIT courses by + + align:start position:0% +free and open access to MIT courses by + + + align:start position:0% +free and open access to MIT courses by +making a donation at ocw mit.edu donate \ No newline at end of file diff --git a/I_w8ruM-mmY.txt b/I_w8ruM-mmY.txt new file mode 100644 index 0000000000000000000000000000000000000000..ce89eb22e1f7fe760baf09b65e65ab53266eaa9a --- /dev/null +++ b/I_w8ruM-mmY.txt @@ -0,0 +1,779 @@ +align:start position:0% + +the inductive attenuator demonstrates + + align:start position:0% +the inductive attenuator demonstrates + + + align:start position:0% +the inductive attenuator demonstrates +the laplacian nature of magnetic fields + + align:start position:0% +the laplacian nature of magnetic fields + + + align:start position:0% +the laplacian nature of magnetic fields +in free space + + align:start position:0% +in free space + + + align:start position:0% +in free space +the way that currents distribute + + align:start position:0% +the way that currents distribute + + + align:start position:0% +the way that currents distribute +themselves on the surfaces of perfect + + align:start position:0% +themselves on the surfaces of perfect + + + align:start position:0% +themselves on the surfaces of perfect +conductors + + align:start position:0% +conductors + + + align:start position:0% +conductors +and the use of the vector potential in + + align:start position:0% +and the use of the vector potential in + + + align:start position:0% +and the use of the vector potential in +describing magnetic fields in + + align:start position:0% +describing magnetic fields in + + + align:start position:0% +describing magnetic fields in +two-dimensional systems + + align:start position:0% + + + + align:start position:0% + +in this model + + align:start position:0% +in this model + + + align:start position:0% +in this model +the floor is the x-y plane + + align:start position:0% +the floor is the x-y plane + + + align:start position:0% +the floor is the x-y plane +the altitude of the surface is the + + align:start position:0% +the altitude of the surface is the + + + align:start position:0% +the altitude of the surface is the +vector potential + + align:start position:0% + + + + align:start position:0% + +here's the direction of periodicity + + align:start position:0% +here's the direction of periodicity + + + align:start position:0% +here's the direction of periodicity +here's the direction of decay + + align:start position:0% + + + + align:start position:0% + +because it represents a solution to + + align:start position:0% +because it represents a solution to + + + align:start position:0% +because it represents a solution to +laplace's equation every point on the + + align:start position:0% +laplace's equation every point on the + + + align:start position:0% +laplace's equation every point on the +surface having a positive curvature + + align:start position:0% +surface having a positive curvature + + + align:start position:0% +surface having a positive curvature +in the y direction + + align:start position:0% +in the y direction + + + align:start position:0% +in the y direction +must have a negative curvature in the x + + align:start position:0% +must have a negative curvature in the x + + + align:start position:0% +must have a negative curvature in the x +direction + + align:start position:0% +direction + + + align:start position:0% +direction +this is why periodicity in one direction + + align:start position:0% +this is why periodicity in one direction + + + align:start position:0% +this is why periodicity in one direction +implies decay in the other + + align:start position:0% + + + + align:start position:0% + +for this solution to laplace's equation + + align:start position:0% +for this solution to laplace's equation + + + align:start position:0% +for this solution to laplace's equation +three of the rectangular boundaries have + + align:start position:0% +three of the rectangular boundaries have + + + align:start position:0% +three of the rectangular boundaries have +a constant vector potential + + align:start position:0% +a constant vector potential + + + align:start position:0% +a constant vector potential +the fourth is a sinusoid + + align:start position:0% +the fourth is a sinusoid + + + align:start position:0% +the fourth is a sinusoid +in our physical situation this fourth + + align:start position:0% +in our physical situation this fourth + + + align:start position:0% +in our physical situation this fourth +boundary is elevated to a uniform vector + + align:start position:0% +boundary is elevated to a uniform vector + + + align:start position:0% +boundary is elevated to a uniform vector +potential + + align:start position:0% + + + + align:start position:0% + +this can be represented by a + + align:start position:0% +this can be represented by a + + + align:start position:0% +this can be represented by a +superposition of these solutions + + align:start position:0% + + + + align:start position:0% + +in our model + + align:start position:0% +in our model + + + align:start position:0% +in our model +lines of constant altitude are lines of + + align:start position:0% +lines of constant altitude are lines of + + + align:start position:0% +lines of constant altitude are lines of +constant vector potential + + align:start position:0% + + + + align:start position:0% + +in two dimensions lines of constant a + + align:start position:0% +in two dimensions lines of constant a + + + align:start position:0% +in two dimensions lines of constant a +sub z + + align:start position:0% +sub z + + + align:start position:0% +sub z +are lines of magnetic flux density + + align:start position:0% +are lines of magnetic flux density + + + align:start position:0% +are lines of magnetic flux density +so the wires are the lines of magnetic + + align:start position:0% +so the wires are the lines of magnetic + + + align:start position:0% +so the wires are the lines of magnetic +flux density + + align:start position:0% + + + + align:start position:0% + +this is the actual apparatus + + align:start position:0% + + + + align:start position:0% + +here are the side walls + + align:start position:0% +here are the side walls + + + align:start position:0% +here are the side walls +insulated from each other + + align:start position:0% + + + + align:start position:0% + +here's the top plate + + align:start position:0% + + + + align:start position:0% + +current from this source passes forward + + align:start position:0% +current from this source passes forward + + + align:start position:0% +current from this source passes forward +through the upper plate + + align:start position:0% +through the upper plate + + + align:start position:0% +through the upper plate +and is returned by the shorts through + + align:start position:0% +and is returned by the shorts through + + + align:start position:0% +and is returned by the shorts through +the side walls + + align:start position:0% + + + + align:start position:0% + +here are the connections at the back end + + align:start position:0% +here are the connections at the back end + + + align:start position:0% +here are the connections at the back end +the source is connected by the center + + align:start position:0% +the source is connected by the center + + + align:start position:0% +the source is connected by the center +conductor of a coaxial cable + + align:start position:0% +conductor of a coaxial cable + + + align:start position:0% +conductor of a coaxial cable +to the upper electrode here + + align:start position:0% + + + + align:start position:0% + +the driving current is returned to the + + align:start position:0% +the driving current is returned to the + + + align:start position:0% +the driving current is returned to the +source by these wires + + align:start position:0% +source by these wires + + + align:start position:0% +source by these wires +and the coax shield conductor + + align:start position:0% + + + + align:start position:0% + +these leads are connected to the top + + align:start position:0% +these leads are connected to the top + + + align:start position:0% +these leads are connected to the top +trace of our scope + + align:start position:0% + + + + align:start position:0% + +the top trace + + align:start position:0% +the top trace + + + align:start position:0% +the top trace +is the driving voltage + + align:start position:0% + + + + align:start position:0% + +here at the back the bottom plate is + + align:start position:0% +here at the back the bottom plate is + + + align:start position:0% +here at the back the bottom plate is +shorted to the side walls + + align:start position:0% + + + + align:start position:0% + +it is also shorted at the front + + align:start position:0% + + + + align:start position:0% + +through these wires + + align:start position:0% + + + + align:start position:0% + +we measure the current induced in this + + align:start position:0% +we measure the current induced in this + + + align:start position:0% +we measure the current induced in this +electrode by means of this current probe + + align:start position:0% + + + + align:start position:0% + +the lower trace on the scope represents + + align:start position:0% +the lower trace on the scope represents + + + align:start position:0% +the lower trace on the scope represents +the output current from the probe + + align:start position:0% +the output current from the probe + + + align:start position:0% +the output current from the probe +it represents the net current induced in + + align:start position:0% +it represents the net current induced in + + + align:start position:0% +it represents the net current induced in +the lower electrode + + align:start position:0% +the lower electrode + + + align:start position:0% +the lower electrode +here's how the current induced in the + + align:start position:0% +here's how the current induced in the + + + align:start position:0% +here's how the current induced in the +lower electrode varies as the driving + + align:start position:0% +lower electrode varies as the driving + + + align:start position:0% +lower electrode varies as the driving +electrode is lowered + + align:start position:0% + + + + align:start position:0% + +as the spacing is increased + + align:start position:0% +as the spacing is increased + + + align:start position:0% +as the spacing is increased +again with the driving voltage + + align:start position:0% +again with the driving voltage + + + align:start position:0% +again with the driving voltage +essentially held fixed + + align:start position:0% +essentially held fixed + + + align:start position:0% +essentially held fixed +the induced current decreases + + align:start position:0% + + + + align:start position:0% + +as the driving electrode approaches the + + align:start position:0% +as the driving electrode approaches the + + + align:start position:0% +as the driving electrode approaches the +lower electrode it increases again + + align:start position:0% + + + + align:start position:0% + +with the electrodes this close almost + + align:start position:0% +with the electrodes this close almost + + + align:start position:0% +with the electrodes this close almost +all of the current in the upper + + align:start position:0% +all of the current in the upper + + + align:start position:0% +all of the current in the upper +electrode is imaged in the lower + + align:start position:0% +electrode is imaged in the lower + + + align:start position:0% +electrode is imaged in the lower +electrode + + align:start position:0% + + + + align:start position:0% + +as the distance between electrodes + + align:start position:0% +as the distance between electrodes + + + align:start position:0% +as the distance between electrodes +increases + + align:start position:0% +increases + + + align:start position:0% +increases +the fraction of the current that returns + + align:start position:0% +the fraction of the current that returns + + + align:start position:0% +the fraction of the current that returns +in the lower electrode + + align:start position:0% +in the lower electrode + + + align:start position:0% +in the lower electrode +is reduced + + align:start position:0% + + + + align:start position:0% + +the inductive attenuator has illustrated + + align:start position:0% +the inductive attenuator has illustrated + + + align:start position:0% +the inductive attenuator has illustrated +the laplacian nature of free space + + align:start position:0% +the laplacian nature of free space + + + align:start position:0% +the laplacian nature of free space +magneto-quasi-static fields + + align:start position:0% + + + + align:start position:0% + +the magnetic field induced by applying a + + align:start position:0% +the magnetic field induced by applying a + + + align:start position:0% +the magnetic field induced by applying a +voltage to the upper electrode + + align:start position:0% +voltage to the upper electrode + + + align:start position:0% +voltage to the upper electrode +decays essentially exponentially into + + align:start position:0% +decays essentially exponentially into + + + align:start position:0% +decays essentially exponentially into +the rectangular region + + align:start position:0% +the rectangular region + + + align:start position:0% +the rectangular region +bounded by the essentially perfectly + + align:start position:0% +bounded by the essentially perfectly + + + align:start position:0% +bounded by the essentially perfectly +conducting side walls + + align:start position:0% +conducting side walls + + + align:start position:0% +conducting side walls +and the bottom electrode + + align:start position:0% + + + + align:start position:0% + +you \ No newline at end of file diff --git a/IfwfCe-JZaI.txt b/IfwfCe-JZaI.txt new file mode 100644 index 0000000000000000000000000000000000000000..e0b8533d89f5f92c94883b831bf81d7bd5f70ff6 --- /dev/null +++ b/IfwfCe-JZaI.txt @@ -0,0 +1,9835 @@ +align:start position:0% + +okay I want to begin by giving some + + align:start position:0% +okay I want to begin by giving some + + + align:start position:0% +okay I want to begin by giving some +comments regarding their Wikipedia + + align:start position:0% +comments regarding their Wikipedia + + + align:start position:0% +comments regarding their Wikipedia +assignment so I sent out an email about + + align:start position:0% +assignment so I sent out an email about + + + align:start position:0% +assignment so I sent out an email about +this last night and so first of all you + + align:start position:0% +this last night and so first of all you + + + align:start position:0% +this last night and so first of all you +know thank you for your contributions to + + align:start position:0% +know thank you for your contributions to + + + align:start position:0% +know thank you for your contributions to +to this assignment to Wikipedia it plays + + align:start position:0% +to this assignment to Wikipedia it plays + + + align:start position:0% +to this assignment to Wikipedia it plays +a really important role in educating a + + align:start position:0% +a really important role in educating a + + + align:start position:0% +a really important role in educating a +wider audience + + align:start position:0% +wider audience + + + align:start position:0% +wider audience +what this subject is about because as + + align:start position:0% +what this subject is about because as + + + align:start position:0% +what this subject is about because as +many of you have experienced the first + + align:start position:0% +many of you have experienced the first + + + align:start position:0% +many of you have experienced the first +time if you heard of some term you have + + align:start position:0% +time if you heard of some term you have + + + align:start position:0% +time if you heard of some term you have +no idea what it is you put it into + + align:start position:0% +no idea what it is you put it into + + + align:start position:0% +no idea what it is you put it into +Google and often Wikipedia entry is one + + align:start position:0% +Google and often Wikipedia entry is one + + + align:start position:0% +Google and often Wikipedia entry is one +of the top results that come up and what + + align:start position:0% +of the top results that come up and what + + + align:start position:0% +of the top results that come up and what +gets written there actually plays a + + align:start position:0% +gets written there actually plays a + + + align:start position:0% +gets written there actually plays a +fairly influential role in educating a + + align:start position:0% +fairly influential role in educating a + + + align:start position:0% +fairly influential role in educating a +broader audience about what this topic + + align:start position:0% +broader audience about what this topic + + + align:start position:0% +broader audience about what this topic +is about and so I won't you emphasize + + align:start position:0% +is about and so I won't you emphasize + + + align:start position:0% +is about and so I won't you emphasize +that you know this is not simply some + + align:start position:0% +that you know this is not simply some + + + align:start position:0% +that you know this is not simply some +homework assignment it's something that + + align:start position:0% +homework assignment it's something that + + + align:start position:0% +homework assignment it's something that +it's a real contribution and it's + + align:start position:0% +it's a real contribution and it's + + + align:start position:0% +it's a real contribution and it's +something that contributes to the + + align:start position:0% +something that contributes to the + + + align:start position:0% +something that contributes to the +dissemination of knowledge and for that + + align:start position:0% +dissemination of knowledge and for that + + + align:start position:0% +dissemination of knowledge and for that +it is really important to do a good job + + align:start position:0% +it is really important to do a good job + + + align:start position:0% +it is really important to do a good job +to do a write to do a well so that next + + align:start position:0% +to do a write to do a well so that next + + + align:start position:0% +to do a write to do a well so that next +time someone maybe even yourselves you + + align:start position:0% +time someone maybe even yourselves you + + + align:start position:0% +time someone maybe even yourselves you +know have you forgotten what the subject + + align:start position:0% +know have you forgotten what the subject + + + align:start position:0% +know have you forgotten what the subject +is about and go back and you want to + + align:start position:0% +is about and go back and you want to + + + align:start position:0% +is about and go back and you want to +look it up again and remind yourself you + + align:start position:0% +look it up again and remind yourself you + + + align:start position:0% +look it up again and remind yourself you +will have a useful resource to look into + + align:start position:0% +will have a useful resource to look into + + + align:start position:0% +will have a useful resource to look into +but also let's say someone wants to find + + align:start position:0% +but also let's say someone wants to find + + + align:start position:0% +but also let's say someone wants to find +out you know what is extrema graph + + align:start position:0% +out you know what is extrema graph + + + align:start position:0% +out you know what is extrema graph +theory about what is additive + + align:start position:0% +theory about what is additive + + + align:start position:0% +theory about what is additive +combinatorics about you want them to + + align:start position:0% +combinatorics about you want them to + + + align:start position:0% +combinatorics about you want them to +land on a page that points you to the + + align:start position:0% +land on a page that points you to the + + + align:start position:0% +land on a page that points you to the +right type of places right that points + + align:start position:0% +right type of places right that points + + + align:start position:0% +right type of places right that points +you to use for resources that opens + + align:start position:0% +you to use for resources that opens + + + align:start position:0% +you to use for resources that opens +doors so that you can explore further + + align:start position:0% +doors so that you can explore further + + + align:start position:0% +doors so that you can explore further +and and some of the contributions indeed + + align:start position:0% +and and some of the contributions indeed + + + align:start position:0% +and and some of the contributions indeed +server well in that purpose it opens + + align:start position:0% +server well in that purpose it opens + + + align:start position:0% +server well in that purpose it opens +doors to many things and part of the + + align:start position:0% +doors to many things and part of the + + + align:start position:0% +doors to many things and part of the +spirit of this assignment is for you to + + align:start position:0% +spirit of this assignment is for you to + + + align:start position:0% +spirit of this assignment is for you to +do your own research do your own + + align:start position:0% +do your own research do your own + + + align:start position:0% +do your own research do your own +literature search to learn more about + + align:start position:0% +literature search to learn more about + + + align:start position:0% +literature search to learn more about +the subject you know more than what has + + align:start position:0% +the subject you know more than what has + + + align:start position:0% +the subject you know more than what has +been taught in this in these lectures so + + align:start position:0% +been taught in this in these lectures so + + + align:start position:0% +been taught in this in these lectures so +that you can write about it on Wikipedia + + align:start position:0% +that you can write about it on Wikipedia + + + align:start position:0% +that you can write about it on Wikipedia +you can link to more references you know + + align:start position:0% +you can link to more references you know + + + align:start position:0% +you can link to more references you know +show the world what this subject is + + align:start position:0% +show the world what this subject is + + + align:start position:0% +show the world what this subject is +about okay can you do with our program + + align:start position:0% +about okay can you do with our program + + + align:start position:0% +about okay can you do with our program +so we spent the past few lectures + + align:start position:0% +so we spent the past few lectures + + + align:start position:0% +so we spent the past few lectures +developing tools regarding the structure + + align:start position:0% +developing tools regarding the structure + + + align:start position:0% +developing tools regarding the structure +of set Edition so that we can + + align:start position:0% +of set Edition so that we can + + + align:start position:0% +of set Edition so that we can +proof Fryman theorem so that's been our + + align:start position:0% +proof Fryman theorem so that's been our + + + align:start position:0% +proof Fryman theorem so that's been our +goal for the past few lectures and today + + align:start position:0% +goal for the past few lectures and today + + + align:start position:0% +goal for the past few lectures and today +will finally prove Freeman's theorem but + + align:start position:0% +will finally prove Freeman's theorem but + + + align:start position:0% +will finally prove Freeman's theorem but +let me first remind you the statement so + + align:start position:0% +let me first remind you the statement so + + + align:start position:0% +let me first remind you the statement so +in fragments theorem we would like to + + align:start position:0% +in fragments theorem we would like to + + + align:start position:0% +in fragments theorem we would like to +show that if you are in a substance if + + align:start position:0% +show that if you are in a substance if + + + align:start position:0% +show that if you are in a substance if +you're in the integers you have a set a + + align:start position:0% +you're in the integers you have a set a + + + align:start position:0% +you're in the integers you have a set a +path bang the doubling doubling constant + + align:start position:0% +path bang the doubling doubling constant + + + align:start position:0% +path bang the doubling doubling constant +constant K then the set must be + + align:start position:0% +constant K then the set must be + + + align:start position:0% +constant K then the set must be +contained in a small generalized + + align:start position:0% +contained in a small generalized + + + align:start position:0% +contained in a small generalized +arithmetic progression down the + + align:start position:0% +arithmetic progression down the + + + align:start position:0% +arithmetic progression down the +dimension and size only a constant + + align:start position:0% +dimension and size only a constant + + + align:start position:0% +dimension and size only a constant +factor larger than a we developed + + align:start position:0% +factor larger than a we developed + + + align:start position:0% +factor larger than a we developed +various tools the past three lectures + + align:start position:0% +various tools the past three lectures + + + align:start position:0% +various tools the past three lectures +building up to various intermediate + + align:start position:0% +building up to various intermediate + + + align:start position:0% +building up to various intermediate +results but we also collected this very + + align:start position:0% +results but we also collected this very + + + align:start position:0% +results but we also collected this very +nice set of tools for proving Freeman's + + align:start position:0% +nice set of tools for proving Freeman's + + + align:start position:0% +nice set of tools for proving Freeman's +theorem so let me review some of them + + align:start position:0% +theorem so let me review some of them + + + align:start position:0% +theorem so let me review some of them +which we'll encounter again today learn + + align:start position:0% +which we'll encounter again today learn + + + align:start position:0% +which we'll encounter again today learn +the karuta inequality tells you that if + + align:start position:0% +the karuta inequality tells you that if + + + align:start position:0% +the karuta inequality tells you that if +you have a set where small toppling then + + align:start position:0% +you have a set where small toppling then + + + align:start position:0% +you have a set where small toppling then +the further inter weighted sums are also + + align:start position:0% +the further inter weighted sums are also + + + align:start position:0% +the further inter weighted sums are also +controlled so I want you to think of + + align:start position:0% +controlled so I want you to think of + + + align:start position:0% +controlled so I want you to think of +these parameters as you know K is a + + align:start position:0% +these parameters as you know K is a + + + align:start position:0% +these parameters as you know K is a +constant so okay some powers to a + + align:start position:0% +constant so okay some powers to a + + + align:start position:0% +constant so okay some powers to a +constant but also I don't really care + + align:start position:0% +constant but also I don't really care + + + align:start position:0% +constant but also I don't really care +about polynomial changes in case so I + + align:start position:0% +about polynomial changes in case so I + + + align:start position:0% +about polynomial changes in case so I +changes in K and view this constant more + + align:start position:0% +changes in K and view this constant more + + + align:start position:0% +changes in K and view this constant more +or less as the origin okay itself so if + + align:start position:0% +or less as the origin okay itself so if + + + align:start position:0% +or less as the origin okay itself so if +some if the a plus a is around the same + + align:start position:0% +some if the a plus a is around the same + + + align:start position:0% +some if the a plus a is around the same +side st. and further iterations also do + + align:start position:0% +side st. and further iterations also do + + + align:start position:0% +side st. and further iterations also do +not change the sizes very much rules are + + align:start position:0% +not change the sizes very much rules are + + + align:start position:0% +not change the sizes very much rules are +covering lemma right so this was some + + align:start position:0% +covering lemma right so this was some + + + align:start position:0% +covering lemma right so this was some +statement that if X plus B looks like it + + align:start position:0% +statement that if X plus B looks like it + + + align:start position:0% +statement that if X plus B looks like it +could be covered by copies of B just in + + align:start position:0% +could be covered by copies of B just in + + + align:start position:0% +could be covered by copies of B just in +terms of their sizes alone then + + align:start position:0% +terms of their sizes alone then + + + align:start position:0% +terms of their sizes alone then +in fact X could be covered by a small + + align:start position:0% +in fact X could be covered by a small + + + align:start position:0% +in fact X could be covered by a small +number translates of a slightly larger + + align:start position:0% +number translates of a slightly larger + + + align:start position:0% +number translates of a slightly larger +ball but here can be any set we have + + align:start position:0% +ball but here can be any set we have + + + align:start position:0% +ball but here can be any set we have +this thing called remodeling lemma in + + align:start position:0% +this thing called remodeling lemma in + + + align:start position:0% +this thing called remodeling lemma in +particular consequence of it is that if + + align:start position:0% +particular consequence of it is that if + + + align:start position:0% +particular consequence of it is that if +a has small doubling then there exists a + + align:start position:0% +a has small doubling then there exists a + + + align:start position:0% +a has small doubling then there exists a +prime and that's not too much bigger + + align:start position:0% +prime and that's not too much bigger + + + align:start position:0% +prime and that's not too much bigger +than the size of a and a very large + + align:start position:0% +than the size of a and a very large + + + align:start position:0% +than the size of a and a very large +proportion an eighth of a subset of + + align:start position:0% +proportion an eighth of a subset of + + + align:start position:0% +proportion an eighth of a subset of +eighth such that the subset a prime is + + align:start position:0% +eighth such that the subset a prime is + + + align:start position:0% +eighth such that the subset a prime is +prime 1/8 isomorphic to a subset of Z + + align:start position:0% +prime 1/8 isomorphic to a subset of Z + + + align:start position:0% +prime 1/8 isomorphic to a subset of Z +mod n so even though you start with a + + align:start position:0% +mod n so even though you start with a + + + align:start position:0% +mod n so even though you start with a +set as potentially very spread out + + align:start position:0% +set as potentially very spread out + + + align:start position:0% +set as potentially very spread out +provided I have small doubling I can + + align:start position:0% +provided I have small doubling I can + + + align:start position:0% +provided I have small doubling I can +pick out a pretty large piece of it and + + align:start position:0% +pick out a pretty large piece of it and + + + align:start position:0% +pick out a pretty large piece of it and +model it by something in a fairly + + align:start position:0% +model it by something in a fairly + + + align:start position:0% +model it by something in a fairly +small cyclic group and here the modeling + + align:start position:0% +small cyclic group and here the modeling + + + align:start position:0% +small cyclic group and here the modeling +is eight isomorphic so it preserves sums + + align:start position:0% +is eight isomorphic so it preserves sums + + + align:start position:0% +is eight isomorphic so it preserves sums +up to eight term songs we had boggling + + align:start position:0% +up to eight term songs we had boggling + + + align:start position:0% +up to eight term songs we had boggling +buffs lemma so now we're inside a small + + align:start position:0% +buffs lemma so now we're inside a small + + + align:start position:0% +buffs lemma so now we're inside a small +cyclic group of a large subset of a + + align:start position:0% +cyclic group of a large subset of a + + + align:start position:0% +cyclic group of a large subset of a +small cyclic group then pokéballs lemma + + align:start position:0% +small cyclic group then pokéballs lemma + + + align:start position:0% +small cyclic group then pokéballs lemma +says that - a - - a contains a + + align:start position:0% +says that - a - - a contains a + + + align:start position:0% +says that - a - - a contains a +large-bore set a large structure within + + align:start position:0% +large-bore set a large structure within + + + align:start position:0% +large-bore set a large structure within +this iterated some set and last time we + + align:start position:0% +this iterated some set and last time we + + + align:start position:0% +this iterated some set and last time we +showed that via geometry of numbers via + + align:start position:0% +showed that via geometry of numbers via + + + align:start position:0% +showed that via geometry of numbers via +minkovski second theorem one can deduce + + align:start position:0% +minkovski second theorem one can deduce + + + align:start position:0% +minkovski second theorem one can deduce +that every bore set of small dimension + + align:start position:0% +that every bore set of small dimension + + + align:start position:0% +that every bore set of small dimension +and and small with contains of large + + align:start position:0% +and and small with contains of large + + + align:start position:0% +and and small with contains of large +with contains a proper gaap that's + + align:start position:0% +with contains a proper gaap that's + + + align:start position:0% +with contains a proper gaap that's +pretty large so putting these two + + align:start position:0% +pretty large so putting these two + + + align:start position:0% +pretty large so putting these two +together putting the last two things + + align:start position:0% +together putting the last two things + + + align:start position:0% +together putting the last two things +together we obtain that if you have a + + align:start position:0% +together we obtain that if you have a + + + align:start position:0% +together we obtain that if you have a +subset of the cyclic group and and prime + + align:start position:0% +subset of the cyclic group and and prime + + + align:start position:0% +subset of the cyclic group and and prime +okay so here previous statements so n is + + align:start position:0% +okay so here previous statements so n is + + + align:start position:0% +okay so here previous statements so n is +prime then and a is pretty large then - + + align:start position:0% +prime then and a is pretty large then - + + + align:start position:0% +prime then and a is pretty large then - +a - - a contains a proper generalized + + align:start position:0% +a - - a contains a proper generalized + + + align:start position:0% +a - - a contains a proper generalized +arithmetic progression of dimension at + + align:start position:0% +arithmetic progression of dimension at + + + align:start position:0% +arithmetic progression of dimension at +most alpha to the minus 2 and size at + + align:start position:0% +most alpha to the minus 2 and size at + + + align:start position:0% +most alpha to the minus 2 and size at +least 1 over 42 d times ok so just + + align:start position:0% +least 1 over 42 d times ok so just + + + align:start position:0% +least 1 over 42 d times ok so just +starting from the size of a - a - - a + + align:start position:0% +starting from the size of a - a - - a + + + align:start position:0% +starting from the size of a - a - - a +contains a pretty large gaap so we're + + align:start position:0% +contains a pretty large gaap so we're + + + align:start position:0% +contains a pretty large gaap so we're +gonna put all of these ingredients + + align:start position:0% +gonna put all of these ingredients + + + align:start position:0% +gonna put all of these ingredients +together and show that you can now + + align:start position:0% +together and show that you can now + + + align:start position:0% +together and show that you can now +contain the original set a in a small JP + + align:start position:0% +contain the original set a in a small JP + + + align:start position:0% +contain the original set a in a small JP +alright so just from knowing that some + + align:start position:0% +alright so just from knowing that some + + + align:start position:0% +alright so just from knowing that some +subset of it - a - 2 m so two things - a + + align:start position:0% +subset of it - a - 2 m so two things - a + + + align:start position:0% +subset of it - a - 2 m so two things - a +prime minus 2 a prime contains this + + align:start position:0% +prime minus 2 a prime contains this + + + align:start position:0% +prime minus 2 a prime contains this +large JP we're going to use it to boost + + align:start position:0% +large JP we're going to use it to boost + + + align:start position:0% +large JP we're going to use it to boost +it up to a cover + + align:start position:0% + + + + align:start position:0% + +okay so now let's proof friends they're + + align:start position:0% + + + + align:start position:0% + +using the modeling memo using the modern + + align:start position:0% +using the modeling memo using the modern + + + align:start position:0% +using the modeling memo using the modern +dilemma the corollary of the modeling + + align:start position:0% +dilemma the corollary of the modeling + + + align:start position:0% +dilemma the corollary of the modeling +memo we find that since a plus a this + + align:start position:0% +memo we find that since a plus a this + + + align:start position:0% +memo we find that since a plus a this +size at most K times the size of a there + + align:start position:0% +size at most K times the size of a there + + + align:start position:0% +size at most K times the size of a there +exists sound Prime and at most 2k to the + + align:start position:0% +exists sound Prime and at most 2k to the + + + align:start position:0% +exists sound Prime and at most 2k to the +16 I'm saying and so I'm just copying + + align:start position:0% +16 I'm saying and so I'm just copying + + + align:start position:0% +16 I'm saying and so I'm just copying +the consequence of this modeling memo so + + align:start position:0% +the consequence of this modeling memo so + + + align:start position:0% +the consequence of this modeling memo so +I find a pretty large subset of a such + + align:start position:0% +I find a pretty large subset of a such + + + align:start position:0% +I find a pretty large subset of a such +that a prime is Fryman 8 isomorphic to a + + align:start position:0% +that a prime is Fryman 8 isomorphic to a + + + align:start position:0% +that a prime is Fryman 8 isomorphic to a +subset of Zima in now applying the final + + align:start position:0% +subset of Zima in now applying the final + + + align:start position:0% +subset of Zima in now applying the final +corollary with alpha being the size of + + align:start position:0% +corollary with alpha being the size of + + + align:start position:0% +corollary with alpha being the size of +this a prime which is at least the size + + align:start position:0% +this a prime which is at least the size + + + align:start position:0% +this a prime which is at least the size +of a over N which is at least 1 over 16 + + align:start position:0% +of a over N which is at least 1 over 16 + + + align:start position:0% +of a over N which is at least 1 over 16 +to the times K to the power 16 so olbes + + align:start position:0% +to the times K to the power 16 so olbes + + + align:start position:0% +to the times K to the power 16 so olbes +constants we see that to a prime - okay + + align:start position:0% +constants we see that to a prime - okay + + + align:start position:0% +constants we see that to a prime - okay +so let me actually let me change the + + align:start position:0% +so let me actually let me change the + + + align:start position:0% +so let me actually let me change the +letters and call a prime B Prime + + align:start position:0% + + + + align:start position:0% + +subset of a is coffee okay so to be - to + + align:start position:0% +subset of a is coffee okay so to be - to + + + align:start position:0% +subset of a is coffee okay so to be - to +be now contains a large GA p and the g + + align:start position:0% +be now contains a large GA p and the g + + + align:start position:0% +be now contains a large GA p and the g +AP has dimension D bounded right so the + + align:start position:0% +AP has dimension D bounded right so the + + + align:start position:0% +AP has dimension D bounded right so the +dimension is bounded by alpha to the + + align:start position:0% +dimension is bounded by alpha to the + + + align:start position:0% +dimension is bounded by alpha to the +minus two so so it's some constant and + + align:start position:0% +minus two so so it's some constant and + + + align:start position:0% +minus two so so it's some constant and +the size is pretty large size is at + + align:start position:0% +the size is pretty large size is at + + + align:start position:0% +the size is pretty large size is at +least one over 40 if you only care about + + align:start position:0% +least one over 40 if you only care about + + + align:start position:0% +least one over 40 if you only care about +constants just remember that everything + + align:start position:0% +constants just remember that everything + + + align:start position:0% +constants just remember that everything +that depends on K or D is a constant + + align:start position:0% + + + + align:start position:0% + +okay because b is Fryman eight + + align:start position:0% +okay because b is Fryman eight + + + align:start position:0% +okay because b is Fryman eight +isomorphic eight isomorphic to be is a + + align:start position:0% +isomorphic eight isomorphic to be is a + + + align:start position:0% +isomorphic eight isomorphic to be is a +prime is a subset of a and b is the + + align:start position:0% +prime is a subset of a and b is the + + + align:start position:0% +prime is a subset of a and b is the +subset of Z mod b is a subset of Z mod n + + align:start position:0% +subset of Z mod b is a subset of Z mod n + + + align:start position:0% +subset of Z mod b is a subset of Z mod n +that a Prime's a isomorphic to so since + + align:start position:0% +that a Prime's a isomorphic to so since + + + align:start position:0% +that a Prime's a isomorphic to so since +P is eight isomorphic to a prime every + + align:start position:0% +P is eight isomorphic to a prime every + + + align:start position:0% +P is eight isomorphic to a prime every +GA p in B also so if you think about + + align:start position:0% +GA p in B also so if you think about + + + align:start position:0% +GA p in B also so if you think about +what eight isomorphism preserves you + + align:start position:0% +what eight isomorphism preserves you + + + align:start position:0% +what eight isomorphism preserves you +find that if you look at to be - to be + + align:start position:0% +find that if you look at to be - to be + + + align:start position:0% +find that if you look at to be - to be +it must be too friendly to isomorphic to + + align:start position:0% +it must be too friendly to isomorphic to + + + align:start position:0% +it must be too friendly to isomorphic to +to a prime minus Q eight right so the + + align:start position:0% +to a prime minus Q eight right so the + + + align:start position:0% +to a prime minus Q eight right so the +point of Fryman isomorphism is that we + + align:start position:0% +point of Fryman isomorphism is that we + + + align:start position:0% +point of Fryman isomorphism is that we +just want in to preserve enough additive + + align:start position:0% +just want in to preserve enough additive + + + align:start position:0% +just want in to preserve enough additive +structure while we're doing to preserve + + align:start position:0% +structure while we're doing to preserve + + + align:start position:0% +structure while we're doing to preserve +all the additive structure + + align:start position:0% +all the additive structure + + + align:start position:0% +all the additive structure +but just enough additive structure to do + + align:start position:0% +but just enough additive structure to do + + + align:start position:0% +but just enough additive structure to do +what we need to do and being able to + + align:start position:0% +what we need to do and being able to + + + align:start position:0% +what we need to do and being able to +preserve an arithmetic progression or in + + align:start position:0% +preserve an arithmetic progression or in + + + align:start position:0% +preserve an arithmetic progression or in +general or generalized arithmetic + + align:start position:0% +general or generalized arithmetic + + + align:start position:0% +general or generalized arithmetic +progression requires you to preserve + + align:start position:0% +progression requires you to preserve + + + align:start position:0% +progression requires you to preserve +Fryman to isomorphism and that's where + + align:start position:0% +Fryman to isomorphism and that's where + + + align:start position:0% +Fryman to isomorphism and that's where +the ink comes in I want to analyze to be + + align:start position:0% +the ink comes in I want to analyze to be + + + align:start position:0% +the ink comes in I want to analyze to be +- to be and I want that preserve to + + align:start position:0% +- to be and I want that preserve to + + + align:start position:0% +- to be and I want that preserve to +isomorphisms so initially I want B to + + align:start position:0% +isomorphisms so initially I want B to + + + align:start position:0% +isomorphisms so initially I want B to +preserve eight isomorphism so - P - 2 + + align:start position:0% +preserve eight isomorphism so - P - 2 + + + align:start position:0% +preserve eight isomorphism so - P - 2 +B's find an isomorphic to - a prime + + align:start position:0% +B's find an isomorphic to - a prime + + + align:start position:0% +B's find an isomorphic to - a prime +minus 2 a prime so the g AP which we + + align:start position:0% +minus 2 a prime so the g AP which we + + + align:start position:0% +minus 2 a prime so the g AP which we +found earlier in 2b minus 2b is mapped + + align:start position:0% +found earlier in 2b minus 2b is mapped + + + align:start position:0% +found earlier in 2b minus 2b is mapped +via this friendly isomorphism to a + + align:start position:0% +via this friendly isomorphism to a + + + align:start position:0% +via this friendly isomorphism to a +proper g AP which we'll call q now + + align:start position:0% +proper g AP which we'll call q now + + + align:start position:0% +proper g AP which we'll call q now +sitting side to a - to it and preserving + + align:start position:0% +sitting side to a - to it and preserving + + + align:start position:0% +sitting side to a - to it and preserving +the same dimension and sighs so Fryman + + align:start position:0% +the same dimension and sighs so Fryman + + + align:start position:0% +the same dimension and sighs so Fryman +isomorphisms are good for preserving + + align:start position:0% +isomorphisms are good for preserving + + + align:start position:0% +isomorphisms are good for preserving +these partial additive structures like + + align:start position:0% +these partial additive structures like + + + align:start position:0% +these partial additive structures like +JPS + + align:start position:0% + + + + align:start position:0% + +correct so questions were you saying so + + align:start position:0% +correct so questions were you saying so + + + align:start position:0% +correct so questions were you saying so +because we have to pass the to be - to + + align:start position:0% +because we have to pass the to be - to + + + align:start position:0% +because we have to pass the to be - to +be we want to be - to be to be friendly + + align:start position:0% +be we want to be - to be to be friendly + + + align:start position:0% +be we want to be - to be to be friendly +isomorphic to - a prime minus 2 a prime + + align:start position:0% +isomorphic to - a prime minus 2 a prime + + + align:start position:0% +isomorphic to - a prime minus 2 a prime +so that's why in the proof I won't be to + + align:start position:0% +so that's why in the proof I won't be to + + + align:start position:0% +so that's why in the proof I won't be to +be 8 isomorphic to a prime so you see so + + align:start position:0% +be 8 isomorphic to a prime so you see so + + + align:start position:0% +be 8 isomorphic to a prime so you see so +I'm skipping details of this step but if + + align:start position:0% +I'm skipping details of this step but if + + + align:start position:0% +I'm skipping details of this step but if +you read the definition of Fryman s + + align:start position:0% +you read the definition of Fryman s + + + align:start position:0% +you read the definition of Fryman s +isomorphism you see that this + + align:start position:0% +isomorphism you see that this + + + align:start position:0% +isomorphism you see that this +implication holds no - isomorphism is a + + align:start position:0% +implication holds no - isomorphism is a + + + align:start position:0% +implication holds no - isomorphism is a +weaker condition to isomorphism just + + align:start position:0% +weaker condition to isomorphism just + + + align:start position:0% +weaker condition to isomorphism just +means that you're preserving two wise + + align:start position:0% +means that you're preserving two wise + + + align:start position:0% +means that you're preserving two wise +sons think about the definition you're + + align:start position:0% +sons think about the definition you're + + + align:start position:0% +sons think about the definition you're +framing to isomorphism in particular if + + align:start position:0% +framing to isomorphism in particular if + + + align:start position:0% +framing to isomorphism in particular if +two sets are Fryman - isomorphic and you + + align:start position:0% +two sets are Fryman - isomorphic and you + + + align:start position:0% +two sets are Fryman - isomorphic and you +have a arithmetic progression in one + + align:start position:0% +have a arithmetic progression in one + + + align:start position:0% +have a arithmetic progression in one +then that arithmetic progression is also + + align:start position:0% +then that arithmetic progression is also + + + align:start position:0% +then that arithmetic progression is also +an arithmetic progression in the other + + align:start position:0% +an arithmetic progression in the other + + + align:start position:0% +an arithmetic progression in the other +okay so it's just enough a data + + align:start position:0% +okay so it's just enough a data + + + align:start position:0% +okay so it's just enough a data +structure to preserve things like + + align:start position:0% +structure to preserve things like + + + align:start position:0% +structure to preserve things like +arithmetic progressions and generalized + + align:start position:0% +arithmetic progressions and generalized + + + align:start position:0% +arithmetic progressions and generalized +arithmetic progressions okay so we found + + align:start position:0% +arithmetic progressions okay so we found + + + align:start position:0% +arithmetic progressions okay so we found +this large GAAP in - a - to it so this + + align:start position:0% +this large GAAP in - a - to it so this + + + align:start position:0% +this large GAAP in - a - to it so this +is this is America so we wanted to + + align:start position:0% +is this is America so we wanted to + + + align:start position:0% +is this is America so we wanted to +contain a in the GAAP seems that playing + + align:start position:0% +contain a in the GAAP seems that playing + + + align:start position:0% +contain a in the GAAP seems that playing +out with doing something sliding the + + align:start position:0% +out with doing something sliding the + + + align:start position:0% +out with doing something sliding the +opposite direction we find a large GA P + + align:start position:0% +opposite direction we find a large GA P + + + align:start position:0% +opposite direction we find a large GA P +within - a - to it but something we've + + align:start position:0% +within - a - to it but something we've + + + align:start position:0% +within - a - to it but something we've +seen before we're going to use this to + + align:start position:0% +seen before we're going to use this to + + + align:start position:0% +seen before we're going to use this to +boost ourselves to a covering of a via + + align:start position:0% +boost ourselves to a covering of a via + + + align:start position:0% +boost ourselves to a covering of a via +the Rouge are covering lemma right so + + align:start position:0% +the Rouge are covering lemma right so + + + align:start position:0% +the Rouge are covering lemma right so +once you find this large structure you + + align:start position:0% +once you find this large structure you + + + align:start position:0% +once you find this large structure you +can now try to take translates of it to + + align:start position:0% +can now try to take translates of it to + + + align:start position:0% +can now try to take translates of it to +cover and this is if there's any take + + align:start position:0% +cover and this is if there's any take + + + align:start position:0% +cover and this is if there's any take +away from the spirit of this proof is + + align:start position:0% +away from the spirit of this proof is + + + align:start position:0% +away from the spirit of this proof is +this idea even though I want to cover + + align:start position:0% +this idea even though I want to cover + + + align:start position:0% +this idea even though I want to cover +the whole set it's okay I just find a + + align:start position:0% +the whole set it's okay I just find a + + + align:start position:0% +the whole set it's okay I just find a +large structure within it and then I use + + align:start position:0% +large structure within it and then I use + + + align:start position:0% +large structure within it and then I use +translates to cover how do we do this + + align:start position:0% +translates to cover how do we do this + + + align:start position:0% +translates to cover how do we do this +so since Q is containing 2a minus 2a we + + align:start position:0% +so since Q is containing 2a minus 2a we + + + align:start position:0% +so since Q is containing 2a minus 2a we +find that Q plus a is containing 3a + + align:start position:0% +find that Q plus a is containing 3a + + + align:start position:0% +find that Q plus a is containing 3a +minus 2a therefore by Clinique Arusha + + align:start position:0% + + + + align:start position:0% + +clinical Russa inequality the size of Q + + align:start position:0% +clinical Russa inequality the size of Q + + + align:start position:0% +clinical Russa inequality the size of Q +plus a is at most the size of 3a minus + + align:start position:0% +plus a is at most the size of 3a minus + + + align:start position:0% +plus a is at most the size of 3a minus +2a which is at most K to the fifth power + + align:start position:0% +2a which is at most K to the fifth power + + + align:start position:0% +2a which is at most K to the fifth power +times the size of a and I claim that + + align:start position:0% +times the size of a and I claim that + + + align:start position:0% +times the size of a and I claim that +this final quantity is also not so + + align:start position:0% +this final quantity is also not so + + + align:start position:0% +this final quantity is also not so +different from the size of Q right + + align:start position:0% +different from the size of Q right + + + align:start position:0% +different from the size of Q right +because okay so all of these I mean the + + align:start position:0% +because okay so all of these I mean the + + + align:start position:0% +because okay so all of these I mean the +point here is we are doing all of these + + align:start position:0% +point here is we are doing all of these + + + align:start position:0% +point here is we are doing all of these +transformations passing down to subsets + + align:start position:0% +transformations passing down to subsets + + + align:start position:0% +transformations passing down to subsets +putting something bigger putting getting + + align:start position:0% +putting something bigger putting getting + + + align:start position:0% +putting something bigger putting getting +to something smaller but each time we + + align:start position:0% +to something smaller but each time we + + + align:start position:0% +to something smaller but each time we +only lose something that is polynomial + + align:start position:0% +only lose something that is polynomial + + + align:start position:0% +only lose something that is polynomial +in K we're not losing much more + + align:start position:0% +in K we're not losing much more + + + align:start position:0% +in K we're not losing much more +I'm also only losing a constant factor + + align:start position:0% +I'm also only losing a constant factor + + + align:start position:0% +I'm also only losing a constant factor +there's sometimes a bit more than more + + align:start position:0% +there's sometimes a bit more than more + + + align:start position:0% +there's sometimes a bit more than more +than polynomial but in any case we're + + align:start position:0% +than polynomial but in any case we're + + + align:start position:0% +than polynomial but in any case we're +losing only a constant factor at each + + align:start position:0% +losing only a constant factor at each + + + align:start position:0% +losing only a constant factor at each +step so in particular since and upper + + align:start position:0% +step so in particular since and upper + + + align:start position:0% +step so in particular since and upper +bounds size a prime and it's larger than + + align:start position:0% +bounds size a prime and it's larger than + + + align:start position:0% +bounds size a prime and it's larger than +a prime which is at least a constant + + align:start position:0% +a prime which is at least a constant + + + align:start position:0% +a prime which is at least a constant +fraction of a and the size of Q is at + + align:start position:0% +fraction of a and the size of Q is at + + + align:start position:0% +fraction of a and the size of Q is at +least one over 40 raised to D times and + + align:start position:0% +least one over 40 raised to D times and + + + align:start position:0% +least one over 40 raised to D times and +so we find that this + + align:start position:0% +so we find that this + + + align:start position:0% +so we find that this +bound upper bound earlier on q+ a we can + + align:start position:0% +bound upper bound earlier on q+ a we can + + + align:start position:0% +bound upper bound earlier on q+ a we can +write it in terms of size of cube where + + align:start position:0% +write it in terms of size of cube where + + + align:start position:0% +write it in terms of size of cube where +K prime is put all of these numbers + + align:start position:0% +K prime is put all of these numbers + + + align:start position:0% +K prime is put all of these numbers +together what it specifically doesn't + + align:start position:0% +together what it specifically doesn't + + + align:start position:0% +together what it specifically doesn't +matter so much other than that it is a + + align:start position:0% +matter so much other than that it is a + + + align:start position:0% +matter so much other than that it is a +constant D is polynomial in K so what we + + align:start position:0% +constant D is polynomial in K so what we + + + align:start position:0% +constant D is polynomial in K so what we +have here is something that's + + align:start position:0% +have here is something that's + + + align:start position:0% +have here is something that's +exponential in the polynomial of K okay + + align:start position:0% +exponential in the polynomial of K okay + + + align:start position:0% +exponential in the polynomial of K okay +so now we're in a position to apply the + + align:start position:0% +so now we're in a position to apply the + + + align:start position:0% +so now we're in a position to apply the +Rouge are covering lemma so look at that + + align:start position:0% +Rouge are covering lemma so look at that + + + align:start position:0% +Rouge are covering lemma so look at that +statement up there so what is it saying + + align:start position:0% +statement up there so what is it saying + + + align:start position:0% +statement up there so what is it saying +that a plus Q looks like it could be + + align:start position:0% +that a plus Q looks like it could be + + + align:start position:0% +that a plus Q looks like it could be +covered by Q just in terms of size so I + + align:start position:0% +covered by Q just in terms of size so I + + + align:start position:0% +covered by Q just in terms of size so I +should expect to cover a by a small + + align:start position:0% +should expect to cover a by a small + + + align:start position:0% +should expect to cover a by a small +number of translates of Q minus Q so by + + align:start position:0% +number of translates of Q minus Q so by + + + align:start position:0% +number of translates of Q minus Q so by +covering lemma a it's contained in some + + align:start position:0% +covering lemma a it's contained in some + + + align:start position:0% +covering lemma a it's contained in some +X plus Q minus Q for some X where the + + align:start position:0% +X plus Q minus Q for some X where the + + + align:start position:0% +X plus Q minus Q for some X where the +size of X is at most K Prime I claim so + + align:start position:0% +size of X is at most K Prime I claim so + + + align:start position:0% +size of X is at most K Prime I claim so +we've covered it by something Q is a ga + + align:start position:0% +we've covered it by something Q is a ga + + + align:start position:0% +we've covered it by something Q is a ga +P X is a bounded size set and I claim + + align:start position:0% +P X is a bounded size set and I claim + + + align:start position:0% +P X is a bounded size set and I claim +that this is the type of object that + + align:start position:0% +that this is the type of object that + + + align:start position:0% +that this is the type of object that +we're happy to have just to spell out + + align:start position:0% +we're happy to have just to spell out + + + align:start position:0% +we're happy to have just to spell out +some details first note that X is + + align:start position:0% +some details first note that X is + + + align:start position:0% +some details first note that X is +contained in a JP dimension x so X minus + + align:start position:0% +contained in a JP dimension x so X minus + + + align:start position:0% +contained in a JP dimension x so X minus +1 with length 2 in each direction + + align:start position:0% + + + + align:start position:0% + +to add a new direction for every element + + align:start position:0% +to add a new direction for every element + + + align:start position:0% +to add a new direction for every element +of X it's wasteful but everything is + + align:start position:0% +of X it's wasteful but everything is + + + align:start position:0% +of X it's wasteful but everything is +constant and recall that the dimension + + align:start position:0% +constant and recall that the dimension + + + align:start position:0% +constant and recall that the dimension +of Q as a G a PSD so X plus Q minus Q is + + align:start position:0% +of Q as a G a PSD so X plus Q minus Q is + + + align:start position:0% +of Q as a G a PSD so X plus Q minus Q is +contained in Ag AP of dimension okay so + + align:start position:0% +contained in Ag AP of dimension okay so + + + align:start position:0% +contained in Ag AP of dimension okay so +what's the dimension also when I do Q + + align:start position:0% +what's the dimension also when I do Q + + + align:start position:0% +what's the dimension also when I do Q +minus Q is like taking a box and + + align:start position:0% +minus Q is like taking a box and + + + align:start position:0% +minus Q is like taking a box and +toppling its dimension doubling its + + align:start position:0% +toppling its dimension doubling its + + + align:start position:0% +toppling its dimension doubling its +length I'm not changing the number of + + align:start position:0% +length I'm not changing the number of + + + align:start position:0% +length I'm not changing the number of +dimensions so the dimension of Q minus Q + + align:start position:0% +dimensions so the dimension of Q minus Q + + + align:start position:0% +dimensions so the dimension of Q minus Q +is still deep a dimension of X is at + + align:start position:0% +is still deep a dimension of X is at + + + align:start position:0% +is still deep a dimension of X is at +most size of X all of these things are + + align:start position:0% +most size of X all of these things are + + + align:start position:0% +most size of X all of these things are +constants so so we're happy but just + + align:start position:0% +constants so so we're happy but just + + + align:start position:0% +constants so so we're happy but just +spell it out the constant here is K + + align:start position:0% +spell it out the constant here is K + + + align:start position:0% +spell it out the constant here is K +prime is what we wrote up there this is + + align:start position:0% +prime is what we wrote up there this is + + + align:start position:0% +prime is what we wrote up there this is +a constant and the size right so what is + + align:start position:0% +a constant and the size right so what is + + + align:start position:0% +a constant and the size right so what is +the size of the gaap that contains this + + align:start position:0% +the size of the gaap that contains this + + + align:start position:0% +the size of the gaap that contains this +guy here so I'm expanding X to a GAAP by + + align:start position:0% +guy here so I'm expanding X to a GAAP by + + + align:start position:0% +guy here so I'm expanding X to a GAAP by +adding a new direction for every element + + align:start position:0% +adding a new direction for every element + + + align:start position:0% +adding a new direction for every element +of X and I might expand that size a + + align:start position:0% +of X and I might expand that size a + + + align:start position:0% +of X and I might expand that size a +little bit but the size of this GAAP + + align:start position:0% +little bit but the size of this GAAP + + + align:start position:0% +little bit but the size of this GAAP +that contains X it's no more than 2 to + + align:start position:0% +that contains X it's no more than 2 to + + + align:start position:0% +that contains X it's no more than 2 to +the power X - 2 raised to the size of X + + align:start position:0% +the power X - 2 raised to the size of X + + + align:start position:0% +the power X - 2 raised to the size of X +when there's the size of the gaap Q - Q + + align:start position:0% +when there's the size of the gaap Q - Q + + + align:start position:0% +when there's the size of the gaap Q - Q +so Q is a JP of dimension D and we know + + align:start position:0% +so Q is a JP of dimension D and we know + + + align:start position:0% +so Q is a JP of dimension D and we know +that a ga P of dimension D has doubling + + align:start position:0% +that a ga P of dimension D has doubling + + + align:start position:0% +that a ga P of dimension D has doubling +constant and those two to the D + + align:start position:0% +constant and those two to the D + + + align:start position:0% +constant and those two to the D +to to the D times the size of you okay + + align:start position:0% +to to the D times the size of you okay + + + align:start position:0% +to to the D times the size of you okay +and because Q is contained in QA - to a + + align:start position:0% +and because Q is contained in QA - to a + + + align:start position:0% +and because Q is contained in QA - to a +we find that Q is contained in to a - 2 + + align:start position:0% +we find that Q is contained in to a - 2 + + + align:start position:0% +we find that Q is contained in to a - 2 +a and 2 to the X well I know what the + + align:start position:0% +a and 2 to the X well I know what the + + + align:start position:0% +a and 2 to the X well I know what the +size of X is bounded by a prime plus the + + align:start position:0% +size of X is bounded by a prime plus the + + + align:start position:0% +size of X is bounded by a prime plus the +size of X is size of X's are most K + + align:start position:0% +size of X is size of X's are most K + + + align:start position:0% +size of X is size of X's are most K +prime and then I have 2 to the D over + + align:start position:0% +prime and then I have 2 to the D over + + + align:start position:0% +prime and then I have 2 to the D over +here - a - to a by Polonia kirusha is + + align:start position:0% +here - a - to a by Polonia kirusha is + + + align:start position:0% +here - a - to a by Polonia kirusha is +our most K to the for the size of a ok + + align:start position:0% +our most K to the for the size of a ok + + + align:start position:0% +our most K to the for the size of a ok +you put everything together we find that + + align:start position:0% +you put everything together we find that + + + align:start position:0% +you put everything together we find that +this bound here is doubly exponential in + + align:start position:0% +this bound here is doubly exponential in + + + align:start position:0% +this bound here is doubly exponential in +the polynomial okay and that's it this + + align:start position:0% +the polynomial okay and that's it this + + + align:start position:0% +the polynomial okay and that's it this +proofs from it's due to recap + + align:start position:0% +proofs from it's due to recap + + + align:start position:0% +proofs from it's due to recap +we went through several steps so first + + align:start position:0% +we went through several steps so first + + + align:start position:0% +we went through several steps so first +using the modeling lemma we know that if + + align:start position:0% +using the modeling lemma we know that if + + + align:start position:0% +using the modeling lemma we know that if +a set a has small doubling then we can + + align:start position:0% +a set a has small doubling then we can + + + align:start position:0% +a set a has small doubling then we can +pass a large part of a to a relatively + + align:start position:0% +pass a large part of a to a relatively + + + align:start position:0% +pass a large part of a to a relatively +small cyclic group I'm going to work + + align:start position:0% +small cyclic group I'm going to work + + + align:start position:0% +small cyclic group I'm going to work +inside a cyclic group using bug Labov + + align:start position:0% +inside a cyclic group using bug Labov + + + align:start position:0% +inside a cyclic group using bug Labov +lemma and and it's geometry of numbers + + align:start position:0% +lemma and and it's geometry of numbers + + + align:start position:0% +lemma and and it's geometry of numbers +corollary which I find that inside the + + align:start position:0% +corollary which I find that inside the + + + align:start position:0% +corollary which I find that inside the +cyclic group the corresponding set which + + align:start position:0% +cyclic group the corresponding set which + + + align:start position:0% +cyclic group the corresponding set which +we call B it's such that 2 B minus 2 B + + align:start position:0% +we call B it's such that 2 B minus 2 B + + + align:start position:0% +we call B it's such that 2 B minus 2 B +contains a large GA P we passed that + + align:start position:0% +contains a large GA P we passed that + + + align:start position:0% +contains a large GA P we passed that +gaap back to the original set a because + + align:start position:0% +gaap back to the original set a because + + + align:start position:0% +gaap back to the original set a because +we are preserving 8 isomorphisms Fryman + + align:start position:0% +we are preserving 8 isomorphisms Fryman + + + align:start position:0% +we are preserving 8 isomorphisms Fryman +8 isomorphisms in Ruza modeling lemma so + + align:start position:0% +8 isomorphisms in Ruza modeling lemma so + + + align:start position:0% +8 isomorphisms in Ruza modeling lemma so +we can pass through the origin of set a + + align:start position:0% +we can pass through the origin of set a + + + align:start position:0% +we can pass through the origin of set a +and find a large GA P in to a minus 2 a + + align:start position:0% +and find a large GA P in to a minus 2 a + + + align:start position:0% +and find a large GA P in to a minus 2 a +once we find as large GA p 2a minus 2 a + + align:start position:0% +once we find as large GA p 2a minus 2 a + + + align:start position:0% +once we find as large GA p 2a minus 2 a +then we're going to use the Ruza + + align:start position:0% +then we're going to use the Ruza + + + align:start position:0% +then we're going to use the Ruza +covering lemma to contain a inside a + + align:start position:0% +covering lemma to contain a inside a + + + align:start position:0% +covering lemma to contain a inside a +small number of translates of this GA p + + align:start position:0% + + + + align:start position:0% + +okay you put all of these things + + align:start position:0% +okay you put all of these things + + + align:start position:0% +okay you put all of these things +together and the appropriate bounds + + align:start position:0% +together and the appropriate bounds + + + align:start position:0% +together and the appropriate bounds +coming from putting the kirusha + + align:start position:0% +coming from putting the kirusha + + + align:start position:0% +coming from putting the kirusha +inequalities and you get and this is a + + align:start position:0% +inequalities and you get and this is a + + + align:start position:0% +inequalities and you get and this is a +proof of Ryman's theorem + + align:start position:0% + + + + align:start position:0% + +okay question how do you make it proper + + align:start position:0% +okay question how do you make it proper + + + align:start position:0% +okay question how do you make it proper +up and tell the step with Q it is still + + align:start position:0% +up and tell the step with Q it is still + + + align:start position:0% +up and tell the step with Q it is still +proper so the very last step over here + + align:start position:0% +proper so the very last step over here + + + align:start position:0% +proper so the very last step over here +it is you might have destroyed + + align:start position:0% +it is you might have destroyed + + + align:start position:0% +it is you might have destroyed +properties so this proof here doesn't + + align:start position:0% +properties so this proof here doesn't + + + align:start position:0% +properties so this proof here doesn't +give you properties so I mention in the + + align:start position:0% +give you properties so I mention in the + + + align:start position:0% +give you properties so I mention in the +beginning that in Fryman serum you can + + align:start position:0% +beginning that in Fryman serum you can + + + align:start position:0% +beginning that in Fryman serum you can +obtain properties of the an additional + + align:start position:0% +obtain properties of the an additional + + + align:start position:0% +obtain properties of the an additional +argument so that I'm not going to show + + align:start position:0% +argument so that I'm not going to show + + + align:start position:0% +argument so that I'm not going to show +this some more work which is related to + + align:start position:0% +this some more work which is related to + + + align:start position:0% +this some more work which is related to +geometry of numbers so from so for + + align:start position:0% +geometry of numbers so from so for + + + align:start position:0% +geometry of numbers so from so for +example you can look up in the textbook + + align:start position:0% +example you can look up in the textbook + + + align:start position:0% +example you can look up in the textbook +by Tao and you see how to get from a + + align:start position:0% +by Tao and you see how to get from a + + + align:start position:0% +by Tao and you see how to get from a +GAAP to contain it in a proper GAAP + + align:start position:0% +GAAP to contain it in a proper GAAP + + + align:start position:0% +GAAP to contain it in a proper GAAP +without losing too much in terms of size + + align:start position:0% +without losing too much in terms of size + + + align:start position:0% +without losing too much in terms of size +so in terms of the man you think about + + align:start position:0% +so in terms of the man you think about + + + align:start position:0% +so in terms of the man you think about +it this way so how when is an one do you + + align:start position:0% +it this way so how when is an one do you + + + align:start position:0% +it this way so how when is an one do you +have something which is not properly + + align:start position:0% +have something which is not properly + + + align:start position:0% +have something which is not properly +when you have and if some linear + + align:start position:0% +when you have and if some linear + + + align:start position:0% +when you have and if some linear +dependence when you have some integer + + align:start position:0% +dependence when you have some integer + + + align:start position:0% +dependence when you have some integer +linear dependence and in that case you + + align:start position:0% +linear dependence and in that case you + + + align:start position:0% +linear dependence and in that case you +kind of lost the dimension we have + + align:start position:0% +kind of lost the dimension we have + + + align:start position:0% +kind of lost the dimension we have +improper news you actually go down the + + align:start position:0% +improper news you actually go down the + + + align:start position:0% +improper news you actually go down the +dimension but then you need to salvage + + align:start position:0% +dimension but then you need to salvage + + + align:start position:0% +dimension but then you need to salvage +to the sides to make sure that the size + + align:start position:0% +to the sides to make sure that the size + + + align:start position:0% +to the sides to make sure that the size +doesn't blow up too much and so there + + align:start position:0% +doesn't blow up too much and so there + + + align:start position:0% +doesn't blow up too much and so there +are some arguments to be done there and + + align:start position:0% +are some arguments to be done there and + + + align:start position:0% +are some arguments to be done there and +we're not gonna do so the question is to + + align:start position:0% +we're not gonna do so the question is to + + + align:start position:0% +we're not gonna do so the question is to +get proper nice do I have to modify the + + align:start position:0% +get proper nice do I have to modify the + + + align:start position:0% +get proper nice do I have to modify the +proof oh can I use Freeman's theorem as + + align:start position:0% +proof oh can I use Freeman's theorem as + + + align:start position:0% +proof oh can I use Freeman's theorem as +witness a black box so my understanding + + align:start position:0% +witness a black box so my understanding + + + align:start position:0% +witness a black box so my understanding +is that you can use the statements a + + align:start position:0% +is that you can use the statements a + + + align:start position:0% +is that you can use the statements a +black box and obtain properties but if + + align:start position:0% +black box and obtain properties but if + + + align:start position:0% +black box and obtain properties but if +you want to get good balance maybe you + + align:start position:0% +you want to get good balance maybe you + + + align:start position:0% +you want to get good balance maybe you +have to go into the proof I'm not sure + + align:start position:0% +have to go into the proof I'm not sure + + + align:start position:0% +have to go into the proof I'm not sure +okay + + align:start position:0% + + + + align:start position:0% + +any more questions all right so + + align:start position:0% +any more questions all right so + + + align:start position:0% +any more questions all right so +so this took a while so this was the + + align:start position:0% +so this took a while so this was the + + + align:start position:0% +so this took a while so this was the +most involved proof we've done in this + + align:start position:0% +most involved proof we've done in this + + + align:start position:0% +most involved proof we've done in this +course so far + + align:start position:0% +course so far + + + align:start position:0% +course so far +improving Freeman's theorems we had to + + align:start position:0% +improving Freeman's theorems we had to + + + align:start position:0% +improving Freeman's theorems we had to +develop a large number of tools and we + + align:start position:0% +develop a large number of tools and we + + + align:start position:0% +develop a large number of tools and we +came up so and we eventually arrived at + + align:start position:0% +came up so and we eventually arrived at + + + align:start position:0% +came up so and we eventually arrived at +you know it's a beautiful theory so this + + align:start position:0% +you know it's a beautiful theory so this + + + align:start position:0% +you know it's a beautiful theory so this +is a fantastic result + + align:start position:0% +is a fantastic result + + + align:start position:0% +is a fantastic result +that gives you an inverse structure + + align:start position:0% +that gives you an inverse structure + + + align:start position:0% +that gives you an inverse structure +something we know that GP s-- have small + + align:start position:0% +something we know that GP s-- have small + + + align:start position:0% +something we know that GP s-- have small +doubling and converts s if something has + + align:start position:0% +doubling and converts s if something has + + + align:start position:0% +doubling and converts s if something has +small doubling it has to in some sense + + align:start position:0% +small doubling it has to in some sense + + + align:start position:0% +small doubling it has to in some sense +look like a GP you see that the proof is + + align:start position:0% +look like a GP you see that the proof is + + + align:start position:0% +look like a GP you see that the proof is +quite involved in has a lot of beautiful + + align:start position:0% +quite involved in has a lot of beautiful + + + align:start position:0% +quite involved in has a lot of beautiful +ideas in the remainder of today's + + align:start position:0% +ideas in the remainder of today's + + + align:start position:0% +ideas in the remainder of today's +lecture I want to present some remarks + + align:start position:0% +lecture I want to present some remarks + + + align:start position:0% +lecture I want to present some remarks +on additional extensions and + + align:start position:0% +on additional extensions and + + + align:start position:0% +on additional extensions and +generalizations of Freeman's theorem and + + align:start position:0% +generalizations of Freeman's theorem and + + + align:start position:0% +generalizations of Freeman's theorem and +what we're not going to do any proofs + + align:start position:0% +what we're not going to do any proofs + + + align:start position:0% +what we're not going to do any proofs +there's a lot of deep and beautiful + + align:start position:0% +there's a lot of deep and beautiful + + + align:start position:0% +there's a lot of deep and beautiful +mathematics that are involved in in the + + align:start position:0% +mathematics that are involved in in the + + + align:start position:0% +mathematics that are involved in in the +subject so this is I want to take you to + + align:start position:0% +subject so this is I want to take you to + + + align:start position:0% +subject so this is I want to take you to +a tour through some of them more things + + align:start position:0% +a tour through some of them more things + + + align:start position:0% +a tour through some of them more things +that we can talk about when it comes to + + align:start position:0% +that we can talk about when it comes to + + + align:start position:0% +that we can talk about when it comes to +fragments theorem but first let me + + align:start position:0% +fragments theorem but first let me + + + align:start position:0% +fragments theorem but first let me +mention a few things that I mentioned + + align:start position:0% +mention a few things that I mentioned + + + align:start position:0% +mention a few things that I mentioned +very quickly when we first introduced + + align:start position:0% +very quickly when we first introduced + + + align:start position:0% +very quickly when we first introduced +Freeman's theorem namely some remarks on + + align:start position:0% +Freeman's theorem namely some remarks on + + + align:start position:0% +Freeman's theorem namely some remarks on +the balance so the proof that we just + + align:start position:0% +the balance so the proof that we just + + + align:start position:0% +the balance so the proof that we just +saw gives you a pound which is basically + + align:start position:0% +saw gives you a pound which is basically + + + align:start position:0% +saw gives you a pound which is basically +exponential in the dimension and doubly + + align:start position:0% +exponential in the dimension and doubly + + + align:start position:0% +exponential in the dimension and doubly +exponential for the size blow up all + + align:start position:0% +exponential for the size blow up all + + + align:start position:0% +exponential for the size blow up all +constants so if that's you only care + + align:start position:0% +constants so if that's you only care + + + align:start position:0% +constants so if that's you only care +about constants then then this is just + + align:start position:0% +about constants then then this is just + + + align:start position:0% +about constants then then this is just +fine but you might ask are we losing too + + align:start position:0% +fine but you might ask are we losing too + + + align:start position:0% +fine but you might ask are we losing too +much what is the the right type of + + align:start position:0% +much what is the the right type of + + + align:start position:0% +much what is the the right type of +dependence so what is the right type of + + align:start position:0% +dependence so what is the right type of + + + align:start position:0% +dependence so what is the right type of +dependence so we saw in an example so we + + align:start position:0% +dependence so we saw in an example so we + + + align:start position:0% +dependence so we saw in an example so we +saw an example where if you start with a + + align:start position:0% +saw an example where if you start with a + + + align:start position:0% +saw an example where if you start with a +being a highly dissociated set where + + align:start position:0% +being a highly dissociated set where + + + align:start position:0% +being a highly dissociated set where +there is basically no additive structure + + align:start position:0% +there is basically no additive structure + + + align:start position:0% +there is basically no additive structure +within a then you do need so this + + align:start position:0% +within a then you do need so this + + + align:start position:0% +within a then you do need so this +example shows that you cannot do better + + align:start position:0% + + + + align:start position:0% + +then polynomial well actually that + + align:start position:0% +then polynomial well actually that + + + align:start position:0% +then polynomial well actually that +linear in K in dimension and exponential + + align:start position:0% +linear in K in dimension and exponential + + + align:start position:0% +linear in K in dimension and exponential +in the size blow-up so in particular you + + align:start position:0% +in the size blow-up so in particular you + + + align:start position:0% +in the size blow-up so in particular you +do need to blow up the size to by by + + align:start position:0% +do need to blow up the size to by by + + + align:start position:0% +do need to blow up the size to by by +some exponential quantity in K so here K + + align:start position:0% +some exponential quantity in K so here K + + + align:start position:0% +some exponential quantity in K so here K +is in this example and you can you can + + align:start position:0% +is in this example and you can you can + + + align:start position:0% +is in this example and you can you can +create modifications of the example to + + align:start position:0% +create modifications of the example to + + + align:start position:0% +create modifications of the example to +keep K constant and a getting larger but + + align:start position:0% +keep K constant and a getting larger but + + + align:start position:0% +keep K constant and a getting larger but +the point is that you cannot do better + + align:start position:0% +the point is that you cannot do better + + + align:start position:0% +the point is that you cannot do better +than this type of dependence simply from + + align:start position:0% +than this type of dependence simply from + + + align:start position:0% +than this type of dependence simply from +that example and it's conjecture that + + align:start position:0% +that example and it's conjecture that + + + align:start position:0% +that example and it's conjecture that +that is the truth we're almost there + + align:start position:0% +that is the truth we're almost there + + + align:start position:0% +that is the truth we're almost there +improving this conjecture but not quite + + align:start position:0% +improving this conjecture but not quite + + + align:start position:0% +improving this conjecture but not quite +although the proof that we just gave is + + align:start position:0% +although the proof that we just gave is + + + align:start position:0% +although the proof that we just gave is +somewhat far because you lose an + + align:start position:0% +somewhat far because you lose an + + + align:start position:0% +somewhat far because you lose an +exponent in each bound there is a + + align:start position:0% +exponent in each bound there is a + + + align:start position:0% +exponent in each bound there is a +refinement of the final step in the + + align:start position:0% +refinement of the final step in the + + + align:start position:0% +refinement of the final step in the +argument so let me comment on that so we + + align:start position:0% +argument so let me comment on that so we + + + align:start position:0% +argument so let me comment on that so we +can refine the final step the final + + align:start position:0% +can refine the final step the final + + + align:start position:0% +can refine the final step the final +steps and proof to get polynomial pounds + + align:start position:0% + + + + align:start position:0% + +to get polynomial pounds which is much + + align:start position:0% +to get polynomial pounds which is much + + + align:start position:0% +to get polynomial pounds which is much +more in the right ballpark compared to + + align:start position:0% +more in the right ballpark compared to + + + align:start position:0% +more in the right ballpark compared to +what we got and the idea is basically + + align:start position:0% +what we got and the idea is basically + + + align:start position:0% +what we got and the idea is basically +over here we used recovering lemma so we + + align:start position:0% +over here we used recovering lemma so we + + + align:start position:0% +over here we used recovering lemma so we +started with that q up there + + align:start position:0% + + + + align:start position:0% + +up until this point you should think of + + align:start position:0% +up until this point you should think of + + + align:start position:0% +up until this point you should think of +this stuff as everything coming from + + align:start position:0% +this stuff as everything coming from + + + align:start position:0% +this stuff as everything coming from +baklava and its corollary so that stays + + align:start position:0% +baklava and its corollary so that stays + + + align:start position:0% +baklava and its corollary so that stays +the same + + align:start position:0% +the same + + + align:start position:0% +the same +another question starting without Q what + + align:start position:0% +another question starting without Q what + + + align:start position:0% +another question starting without Q what +would you use how would you use this Q + + align:start position:0% +would you use how would you use this Q + + + align:start position:0% +would you use how would you use this Q +to try to cover a wholly this a applied + + align:start position:0% +to try to cover a wholly this a applied + + + align:start position:0% +to try to cover a wholly this a applied +which are covering lemma remember how + + align:start position:0% +which are covering lemma remember how + + + align:start position:0% +which are covering lemma remember how +the proof which are covering lemma goes + + align:start position:0% +the proof which are covering lemma goes + + + align:start position:0% +the proof which are covering lemma goes +you take a maximal set of translates + + align:start position:0% +you take a maximal set of translates + + + align:start position:0% +you take a maximal set of translates +destroying translates and if you blow + + align:start position:0% +destroying translates and if you blow + + + align:start position:0% +destroying translates and if you blow +everything up by a factor to that you + + align:start position:0% +everything up by a factor to that you + + + align:start position:0% +everything up by a factor to that you +get a cover but it turns out to be + + align:start position:0% +get a cover but it turns out to be + + + align:start position:0% +get a cover but it turns out to be +somewhat wasteful you see there's a lot + + align:start position:0% +somewhat wasteful you see there's a lot + + + align:start position:0% +somewhat wasteful you see there's a lot +of wasting going from X to 2 to the X so + + align:start position:0% +of wasting going from X to 2 to the X so + + + align:start position:0% +of wasting going from X to 2 to the X so +you could do that step more slowly so so + + align:start position:0% +you could do that step more slowly so so + + + align:start position:0% +you could do that step more slowly so so +starting with Q cover now some not all + + align:start position:0% +starting with Q cover now some not all + + + align:start position:0% +starting with Q cover now some not all +of a so cover parts of it by translates + + align:start position:0% + + + + align:start position:0% + +to minus Q so we do reach are covering + + align:start position:0% +to minus Q so we do reach are covering + + + align:start position:0% +to minus Q so we do reach are covering +them out you don't cover the whole thing + + align:start position:0% +them out you don't cover the whole thing + + + align:start position:0% +them out you don't cover the whole thing +but nibble away cover a little bit and + + align:start position:0% +but nibble away cover a little bit and + + + align:start position:0% +but nibble away cover a little bit and +then look at the thing that you get + + align:start position:0% +then look at the thing that you get + + + align:start position:0% +then look at the thing that you get +which is Q becomes some new thing let's + + align:start position:0% +which is Q becomes some new thing let's + + + align:start position:0% +which is Q becomes some new thing let's +say Q 1 I now cover more by Q 1 minus Q + + align:start position:0% +say Q 1 I now cover more by Q 1 minus Q + + + align:start position:0% +say Q 1 I now cover more by Q 1 minus Q +1 so apparently if you do the covering + + align:start position:0% +1 so apparently if you do the covering + + + align:start position:0% +1 so apparently if you do the covering +step more slowly you can obtain better + + align:start position:0% +step more slowly you can obtain better + + + align:start position:0% +step more slowly you can obtain better +bounce and that's enough to save you + + align:start position:0% +bounce and that's enough to save you + + + align:start position:0% +bounce and that's enough to save you +this exponent that go down to + + align:start position:0% +this exponent that go down to + + + align:start position:0% +this exponent that go down to +exponential battle to go down to + + align:start position:0% +exponential battle to go down to + + + align:start position:0% +exponential battle to go down to +polynomial type bounds for fragments + + align:start position:0% +polynomial type bounds for fragments + + + align:start position:0% +polynomial type bounds for fragments +theorem this is roughly the idea so you + + align:start position:0% +theorem this is roughly the idea so you + + + align:start position:0% +theorem this is roughly the idea so you +can modify the final step to obtain this + + align:start position:0% +can modify the final step to obtain this + + + align:start position:0% +can modify the final step to obtain this +bound the best bound so far is due to + + align:start position:0% +bound the best bound so far is due to + + + align:start position:0% +bound the best bound so far is due to +Tom Sanders who proved Freeman's theorem + + align:start position:0% +Tom Sanders who proved Freeman's theorem + + + align:start position:0% +Tom Sanders who proved Freeman's theorem +for + + align:start position:0% +for + + + align:start position:0% +for +pounds dimension that's like K times + + align:start position:0% +pounds dimension that's like K times + + + align:start position:0% +pounds dimension that's like K times +polynomial of then this poly logarithmic + + align:start position:0% +polynomial of then this poly logarithmic + + + align:start position:0% +polynomial of then this poly logarithmic +factor it's basically the right answer + + align:start position:0% +factor it's basically the right answer + + + align:start position:0% +factor it's basically the right answer +so this proof is much more sophisticated + + align:start position:0% +so this proof is much more sophisticated + + + align:start position:0% +so this proof is much more sophisticated +so it goes goes much more in-depth into + + align:start position:0% +so it goes goes much more in-depth into + + + align:start position:0% +so it goes goes much more in-depth into +analyzing the structure of set addition + + align:start position:0% +analyzing the structure of set addition + + + align:start position:0% +analyzing the structure of set addition +so senders is a very nice survey article + + align:start position:0% +so senders is a very nice survey article + + + align:start position:0% +so senders is a very nice survey article +called the structure of said addition + + align:start position:0% +called the structure of said addition + + + align:start position:0% +called the structure of said addition +that analyzes some of the modern + + align:start position:0% +that analyzes some of the modern + + + align:start position:0% +that analyzes some of the modern +techniques that are used to prove these + + align:start position:0% +techniques that are used to prove these + + + align:start position:0% +techniques that are used to prove these +types of results there is one more issue + + align:start position:0% +types of results there is one more issue + + + align:start position:0% +types of results there is one more issue +which I want to discuss at length in the + + align:start position:0% +which I want to discuss at length in the + + + align:start position:0% +which I want to discuss at length in the +second half of this lecture which is + + align:start position:0% +second half of this lecture which is + + + align:start position:0% +second half of this lecture which is +that you might be very unhappy with this + + align:start position:0% +that you might be very unhappy with this + + + align:start position:0% +that you might be very unhappy with this +exponential blow-up because if you think + + align:start position:0% +exponential blow-up because if you think + + + align:start position:0% +exponential blow-up because if you think +about what happens in these examples or + + align:start position:0% +about what happens in these examples or + + + align:start position:0% +about what happens in these examples or +not the examples but if you think about + + align:start position:0% +not the examples but if you think about + + + align:start position:0% +not the examples but if you think about +what happens like the spirit what we're + + align:start position:0% +what happens like the spirit what we're + + + align:start position:0% +what happens like the spirit what we're +trying to say + + align:start position:0% +trying to say + + + align:start position:0% +trying to say +Fryman Sturm is some kind of an inverse + + align:start position:0% +Fryman Sturm is some kind of an inverse + + + align:start position:0% +Fryman Sturm is some kind of an inverse +theorem and to go forward you're trying + + align:start position:0% +theorem and to go forward you're trying + + + align:start position:0% +theorem and to go forward you're trying +to say that if you have a ga P of + + align:start position:0% +to say that if you have a ga P of + + + align:start position:0% +to say that if you have a ga P of +dimension D then the size blow up is + + align:start position:0% +dimension D then the size blow up is + + + align:start position:0% +dimension D then the size blow up is +like 2 to the D right so we want to say + + align:start position:0% +like 2 to the D right so we want to say + + + align:start position:0% +like 2 to the D right so we want to say +some structure + + align:start position:0% + + + + align:start position:0% + +price small topic and finance theorem + + align:start position:0% +price small topic and finance theorem + + + align:start position:0% +price small topic and finance theorem +tells the reverse that you have small + + align:start position:0% +tells the reverse that you have small + + + align:start position:0% +tells the reverse that you have small +doubling then you obtain this structure + + align:start position:0% +doubling then you obtain this structure + + + align:start position:0% +doubling then you obtain this structure +and seems like you are losing I mean + + align:start position:0% +and seems like you are losing I mean + + + align:start position:0% +and seems like you are losing I mean +getting from here to here there is a + + align:start position:0% +getting from here to here there is a + + + align:start position:0% +getting from here to here there is a +polynomial type of loss whereas going + + align:start position:0% +polynomial type of loss whereas going + + + align:start position:0% +polynomial type of loss whereas going +from here to here it seems that we're + + align:start position:0% +from here to here it seems that we're + + + align:start position:0% +from here to here it seems that we're +incurring some exponential type of loss + + align:start position:0% +incurring some exponential type of loss + + + align:start position:0% +incurring some exponential type of loss +and you'll be nice to have some kind of + + align:start position:0% +and you'll be nice to have some kind of + + + align:start position:0% +and you'll be nice to have some kind of +inverse theorem that also preserves + + align:start position:0% +inverse theorem that also preserves + + + align:start position:0% +inverse theorem that also preserves +these relationships qualitatively so + + align:start position:0% +these relationships qualitatively so + + + align:start position:0% +these relationships qualitatively so +that may not make sense in this moment + + align:start position:0% +that may not make sense in this moment + + + align:start position:0% +that may not make sense in this moment +but we'll get back to it later the + + align:start position:0% +but we'll get back to it later the + + + align:start position:0% +but we'll get back to it later the +structure point is there's more than + + align:start position:0% +structure point is there's more than + + + align:start position:0% +structure point is there's more than +this much more to be said about the + + align:start position:0% +this much more to be said about the + + + align:start position:0% +this much more to be said about the +bounds here even though right now it + + align:start position:0% +bounds here even though right now it + + + align:start position:0% +bounds here even though right now it +looks as if they're very close to each + + align:start position:0% +looks as if they're very close to each + + + align:start position:0% +looks as if they're very close to each +other one more thing that I want to + + align:start position:0% +other one more thing that I want to + + + align:start position:0% +other one more thing that I want to +expand on is we've stated and proved + + align:start position:0% +expand on is we've stated and proved + + + align:start position:0% +expand on is we've stated and proved +Freeman's theorem in the integers and + + align:start position:0% +Freeman's theorem in the integers and + + + align:start position:0% +Freeman's theorem in the integers and +you might ask what about in other groups + + align:start position:0% +you might ask what about in other groups + + + align:start position:0% +you might ask what about in other groups +we also proved Freeman's theorem in f2 + + align:start position:0% +we also proved Freeman's theorem in f2 + + + align:start position:0% +we also proved Freeman's theorem in f2 +to the M or more generally groups of + + align:start position:0% +to the M or more generally groups of + + + align:start position:0% +to the M or more generally groups of +bounded exponent of bounded portion so + + align:start position:0% +bounded exponent of bounded portion so + + + align:start position:0% +bounded exponent of bounded portion so +billion groups have bounded exponent for + + align:start position:0% +billion groups have bounded exponent for + + + align:start position:0% +billion groups have bounded exponent for +general abelian groups so general groups + + align:start position:0% + + + + align:start position:0% + +you might ask what happens here and in + + align:start position:0% +you might ask what happens here and in + + + align:start position:0% +you might ask what happens here and in +some sense what is even the statement of + + align:start position:0% +some sense what is even the statement of + + + align:start position:0% +some sense what is even the statement of +the theorem we want something which + + align:start position:0% +the theorem we want something which + + + align:start position:0% +the theorem we want something which +combines somehow two different types of + + align:start position:0% +combines somehow two different types of + + + align:start position:0% +combines somehow two different types of +behavior on one hand you have Z which is + + align:start position:0% +behavior on one hand you have Z which is + + + align:start position:0% +behavior on one hand you have Z which is +what we just did and here the model + + align:start position:0% +what we just did and here the model + + + align:start position:0% +what we just did and here the model +structures are G APs and on the other + + align:start position:0% +structures are G APs and on the other + + + align:start position:0% +structures are G APs and on the other +hand we have which we also proved things + + align:start position:0% +hand we have which we also proved things + + + align:start position:0% +hand we have which we also proved things +like f2 to the M where the model + + align:start position:0% +like f2 to the M where the model + + + align:start position:0% +like f2 to the M where the model +structures are subgroups and there's a + + align:start position:0% +structures are subgroups and there's a + + + align:start position:0% +structures are subgroups and there's a +sense in which these are not the G ApS + + align:start position:0% +sense in which these are not the G ApS + + + align:start position:0% +sense in which these are not the G ApS +or subgroups they have some similar + + align:start position:0% +or subgroups they have some similar + + + align:start position:0% +or subgroups they have some similar +properties but they're now really like + + align:start position:0% +properties but they're now really like + + + align:start position:0% +properties but they're now really like +each other + + align:start position:0% +each other + + + align:start position:0% +each other +so now if I give you a general group + + align:start position:0% +so now if I give you a general group + + + align:start position:0% +so now if I give you a general group +which might be some combination of + + align:start position:0% +which might be some combination of + + + align:start position:0% +which might be some combination of +infinite portion or very large torsion + + align:start position:0% +infinite portion or very large torsion + + + align:start position:0% +infinite portion or very large torsion +elements versus very small portion + + align:start position:0% +elements versus very small portion + + + align:start position:0% +elements versus very small portion +elements so for example take a Cartesian + + align:start position:0% +elements so for example take a Cartesian + + + align:start position:0% +elements so for example take a Cartesian +product of these groups is there a + + align:start position:0% +product of these groups is there a + + + align:start position:0% +product of these groups is there a +freeman's theorem and what as such a + + align:start position:0% +freeman's theorem and what as such a + + + align:start position:0% +freeman's theorem and what as such a +theorem looked like what are the + + align:start position:0% +theorem looked like what are the + + + align:start position:0% +theorem looked like what are the +structures what are the subsets of + + align:start position:0% +structures what are the subsets of + + + align:start position:0% +structures what are the subsets of +bounded doubly so that's kind of thing + + align:start position:0% +bounded doubly so that's kind of thing + + + align:start position:0% +bounded doubly so that's kind of thing +we want to think about so it turns out + + align:start position:0% +we want to think about so it turns out + + + align:start position:0% +we want to think about so it turns out +for Prime Minster mean fine in general + + align:start position:0% +for Prime Minster mean fine in general + + + align:start position:0% +for Prime Minster mean fine in general +abelian groups okay so there is a + + align:start position:0% +abelian groups okay so there is a + + + align:start position:0% +abelian groups okay so there is a +theorem so this theorem was proved by + + align:start position:0% +theorem so this theorem was proved by + + + align:start position:0% +theorem so this theorem was proved by +Green and Russia + + align:start position:0% + + + + align:start position:0% + +so following a very similar type of + + align:start position:0% +so following a very similar type of + + + align:start position:0% +so following a very similar type of +proof framework although it be + + align:start position:0% +proof framework although it be + + + align:start position:0% +proof framework although it be +individual steps in particular the + + align:start position:0% +individual steps in particular the + + + align:start position:0% +individual steps in particular the +modeling lemma needs to be modified and + + align:start position:0% +modeling lemma needs to be modified and + + + align:start position:0% +modeling lemma needs to be modified and +let me tell you about the statement is + + align:start position:0% +let me tell you about the statement is + + + align:start position:0% +let me tell you about the statement is +so the common generalization of GA piece + + align:start position:0% +so the common generalization of GA piece + + + align:start position:0% +so the common generalization of GA piece +and subgroups is something called a + + align:start position:0% +and subgroups is something called a + + + align:start position:0% +and subgroups is something called a +coset progression so a coset progression + + align:start position:0% +coset progression so a coset progression + + + align:start position:0% +coset progression so a coset progression +is a subset which is a direct sum of the + + align:start position:0% +is a subset which is a direct sum of the + + + align:start position:0% +is a subset which is a direct sum of the +form p plus h where p is a proper gaap + + align:start position:0% + + + + align:start position:0% + +definition of GA p works just fine in + + align:start position:0% +definition of GA p works just fine in + + + align:start position:0% +definition of GA p works just fine in +every abelian group where you start with + + align:start position:0% +every abelian group where you start with + + + align:start position:0% +every abelian group where you start with +an initial point a few directions and + + align:start position:0% +an initial point a few directions and + + + align:start position:0% +an initial point a few directions and +you look at a great expansion of those + + align:start position:0% +you look at a great expansion of those + + + align:start position:0% +you look at a great expansion of those +directions piece of property a P and H + + align:start position:0% +directions piece of property a P and H + + + align:start position:0% +directions piece of property a P and H +is a subgroup and here the direct sum + + align:start position:0% +is a subgroup and here the direct sum + + + align:start position:0% +is a subgroup and here the direct sum +refers to fact that every so if P plus h + + align:start position:0% +refers to fact that every so if P plus h + + + align:start position:0% +refers to fact that every so if P plus h +equals to P prime plus h prime for some + + align:start position:0% +equals to P prime plus h prime for some + + + align:start position:0% +equals to P prime plus h prime for some +P and P Prime Minister set P and H H + + align:start position:0% +P and P Prime Minister set P and H H + + + align:start position:0% +P and P Prime Minister set P and H H +prime is a set H then P equals to P + + align:start position:0% +prime is a set H then P equals to P + + + align:start position:0% +prime is a set H then P equals to P +Prime and H + + align:start position:0% +Prime and H + + + align:start position:0% +Prime and H +so every element in here is written in a + + align:start position:0% +so every element in here is written in a + + + align:start position:0% +so every element in here is written in a +unique way as some people some age so + + align:start position:0% +unique way as some people some age so + + + align:start position:0% +unique way as some people some age so +that's what I mean by director song for + + align:start position:0% +that's what I mean by director song for + + + align:start position:0% +that's what I mean by director song for +such an object so such a concept + + align:start position:0% +such an object so such a concept + + + align:start position:0% +such an object so such a concept +progression I call it's dimension to be + + align:start position:0% +progression I call it's dimension to be + + + align:start position:0% +progression I call it's dimension to be +the dimension of the GA P P and its size + + align:start position:0% +the dimension of the GA P P and its size + + + align:start position:0% +the dimension of the GA P P and its size +in this case actually it's just the size + + align:start position:0% +in this case actually it's just the size + + + align:start position:0% +in this case actually it's just the size +of the set which is also the size P + + align:start position:0% +of the set which is also the size P + + + align:start position:0% +of the set which is also the size P +times the size of H so the theorem is + + align:start position:0% +times the size of H so the theorem is + + + align:start position:0% +times the size of H so the theorem is +that if a is a subset of an arbitrary + + align:start position:0% +that if a is a subset of an arbitrary + + + align:start position:0% +that if a is a subset of an arbitrary +abelian group and it has founded + + align:start position:0% +abelian group and it has founded + + + align:start position:0% +abelian group and it has founded +toppling then a is contained in a coset + + align:start position:0% +toppling then a is contained in a coset + + + align:start position:0% +toppling then a is contained in a coset +progression founded dimension and size + + align:start position:0% +progression founded dimension and size + + + align:start position:0% +progression founded dimension and size +founded blow-up of the size of a and + + align:start position:0% +founded blow-up of the size of a and + + + align:start position:0% +founded blow-up of the size of a and +here these constants P and K they are + + align:start position:0% +here these constants P and K they are + + + align:start position:0% +here these constants P and K they are +universal they do not depend on the + + align:start position:0% +universal they do not depend on the + + + align:start position:0% +universal they do not depend on the +group so there are some specific numbers + + align:start position:0% +group so there are some specific numbers + + + align:start position:0% +group so there are some specific numbers +functions you can write down they do not + + align:start position:0% +functions you can write down they do not + + + align:start position:0% +functions you can write down they do not +depend on the group so so this theorem + + align:start position:0% +depend on the group so so this theorem + + + align:start position:0% +depend on the group so so this theorem +gives you the characterization of + + align:start position:0% +gives you the characterization of + + + align:start position:0% +gives you the characterization of +subsets in general abelian groups that + + align:start position:0% +subsets in general abelian groups that + + + align:start position:0% +subsets in general abelian groups that +have small toppling any questions + + align:start position:0% + + + + align:start position:0% + +that's a good question so I think you + + align:start position:0% +that's a good question so I think you + + + align:start position:0% +that's a good question so I think you +could go into their paper and see that + + align:start position:0% +could go into their paper and see that + + + align:start position:0% +could go into their paper and see that +you can get polynomial type bounds and I + + align:start position:0% +you can get polynomial type bounds and I + + + align:start position:0% +you can get polynomial type bounds and I +think Sanders results also work for this + + align:start position:0% +think Sanders results also work for this + + + align:start position:0% +think Sanders results also work for this +type of setting to give you these type + + align:start position:0% +type of setting to give you these type + + + align:start position:0% +type of setting to give you these type +of bounds but I yeah so she's looking to + + align:start position:0% +of bounds but I yeah so she's looking to + + + align:start position:0% +of bounds but I yeah so she's looking to +Sanders paper and you are explaining I + + align:start position:0% +Sanders paper and you are explaining I + + + align:start position:0% +Sanders paper and you are explaining I +think incentives paper + + align:start position:0% +think incentives paper + + + align:start position:0% +think incentives paper +he works in general billion groups the + + align:start position:0% +he works in general billion groups the + + + align:start position:0% +he works in general billion groups the +next question I want to address is okay + + align:start position:0% +next question I want to address is okay + + + align:start position:0% +next question I want to address is okay +what do you think is the next question + + align:start position:0% +what do you think is the next question + + + align:start position:0% +what do you think is the next question +another billion groups so fragments + + align:start position:0% +another billion groups so fragments + + + align:start position:0% +another billion groups so fragments +theorem in non abelian groups or rather + + align:start position:0% +theorem in non abelian groups or rather + + + align:start position:0% +theorem in non abelian groups or rather +the Fryman problem now here's a basic + + align:start position:0% +the Fryman problem now here's a basic + + + align:start position:0% +the Fryman problem now here's a basic +question if I guess there's non abelian + + align:start position:0% +question if I guess there's non abelian + + + align:start position:0% +question if I guess there's non abelian +group what subsets I've found the table + + align:start position:0% +group what subsets I've found the table + + + align:start position:0% +group what subsets I've found the table +of course the examples from abelian + + align:start position:0% +of course the examples from abelian + + + align:start position:0% +of course the examples from abelian +groups also working non abelian groups + + align:start position:0% +groups also working non abelian groups + + + align:start position:0% +groups also working non abelian groups +well you have subgroups you have + + align:start position:0% +well you have subgroups you have + + + align:start position:0% +well you have subgroups you have +generalized arithmetic progressions but + + align:start position:0% +generalized arithmetic progressions but + + + align:start position:0% +generalized arithmetic progressions but +are they're genuinely new examples of + + align:start position:0% +are they're genuinely new examples of + + + align:start position:0% +are they're genuinely new examples of +sets in non abelian groups that have + + align:start position:0% +sets in non abelian groups that have + + + align:start position:0% +sets in non abelian groups that have +bounded doubly so think about that and + + align:start position:0% +bounded doubly so think about that and + + + align:start position:0% +bounded doubly so think about that and +let's take a quick break + + align:start position:0% + + + + align:start position:0% + +okay can you think of examples seeing + + align:start position:0% +okay can you think of examples seeing + + + align:start position:0% +okay can you think of examples seeing +non abelian groups that have small + + align:start position:0% +non abelian groups that have small + + + align:start position:0% +non abelian groups that have small +doubling that do not come from the + + align:start position:0% +doubling that do not come from the + + + align:start position:0% +doubling that do not come from the +examples that we have seen before so let + + align:start position:0% +examples that we have seen before so let + + + align:start position:0% +examples that we have seen before so let +me show you one construction and this is + + align:start position:0% +me show you one construction and this is + + + align:start position:0% +me show you one construction and this is +an important construction in for non + + align:start position:0% +an important construction in for non + + + align:start position:0% +an important construction in for non +abelian groups so it has a name it's + + align:start position:0% +abelian groups so it has a name it's + + + align:start position:0% +abelian groups so it has a name it's +called a discrete Heisenberg which is + + align:start position:0% +called a discrete Heisenberg which is + + + align:start position:0% +called a discrete Heisenberg which is +the matrix consisting of matrices that + + align:start position:0% +the matrix consisting of matrices that + + + align:start position:0% +the matrix consisting of matrices that +look like what I've written so yeah + + align:start position:0% +look like what I've written so yeah + + + align:start position:0% +look like what I've written so yeah +integer entries above the diagonal one + + align:start position:0% +integer entries above the diagonal one + + + align:start position:0% +integer entries above the diagonal one +on the diagonal and zero below the back + + align:start position:0% +on the diagonal and zero below the back + + + align:start position:0% +on the diagonal and zero below the back +so let's do some elementary matrix + + align:start position:0% +so let's do some elementary matrix + + + align:start position:0% +so let's do some elementary matrix +multiplication to see how good + + align:start position:0% +multiplication to see how good + + + align:start position:0% +multiplication to see how good +multiplication in this group works so if + + align:start position:0% +multiplication in this group works so if + + + align:start position:0% +multiplication in this group works so if +I have two such matrices I multiply them + + align:start position:0% +I have two such matrices I multiply them + + + align:start position:0% +I have two such matrices I multiply them +together and then you see that the + + align:start position:0% +together and then you see that the + + + align:start position:0% +together and then you see that the +diagnosed preserved of course but the + + align:start position:0% +diagnosed preserved of course but the + + + align:start position:0% +diagnosed preserved of course but the +this entry over here is simply addition + + align:start position:0% +this entry over here is simply addition + + + align:start position:0% +this entry over here is simply addition +so this entry here is just addition this + + align:start position:0% +so this entry here is just addition this + + + align:start position:0% +so this entry here is just addition this +entry over here it's also addition and + + align:start position:0% +entry over here it's also addition and + + + align:start position:0% +entry over here it's also addition and +the top right entry is a bit more + + align:start position:0% +the top right entry is a bit more + + + align:start position:0% +the top right entry is a bit more +complicated it's some addition but + + align:start position:0% +complicated it's some addition but + + + align:start position:0% +complicated it's some addition but +there's an additional twist + + align:start position:0% + + + + align:start position:0% + +so this is how matrix multiplication + + align:start position:0% +so this is how matrix multiplication + + + align:start position:0% +so this is how matrix multiplication +works in this group I mean this whole + + align:start position:0% +works in this group I mean this whole + + + align:start position:0% +works in this group I mean this whole +matrix multiplication works but in terms + + align:start position:0% +matrix multiplication works but in terms + + + align:start position:0% +matrix multiplication works but in terms +of so you see it's kind of like an + + align:start position:0% +of so you see it's kind of like an + + + align:start position:0% +of so you see it's kind of like an +abelian group but there's an extra twist + + align:start position:0% +abelian group but there's an extra twist + + + align:start position:0% +abelian group but there's an extra twist +so it's almost a billion first step you + + align:start position:0% +so it's almost a billion first step you + + + align:start position:0% +so it's almost a billion first step you +can take away from the billion and and + + align:start position:0% +can take away from the billion and and + + + align:start position:0% +can take away from the billion and and +there's a way to quantify this notions + + align:start position:0% +there's a way to quantify this notions + + + align:start position:0% +there's a way to quantify this notions +called neo potency so we'll get to that + + align:start position:0% +called neo potency so we'll get to that + + + align:start position:0% +called neo potency so we'll get to that +in a second but in particular if you set + + align:start position:0% +in a second but in particular if you set + + + align:start position:0% +in a second but in particular if you set +s to be the following generators so if + + align:start position:0% +s to be the following generators so if + + + align:start position:0% +s to be the following generators so if +you take s the babies four elements and + + align:start position:0% +you take s the babies four elements and + + + align:start position:0% +you take s the babies four elements and +you ask what does the RF power of s + + align:start position:0% +you ask what does the RF power of s + + + align:start position:0% +you ask what does the RF power of s +looked like so I look at all the + + align:start position:0% +looked like so I look at all the + + + align:start position:0% +looked like so I look at all the +elements which can be written by our or + + align:start position:0% +elements which can be written by our or + + + align:start position:0% +elements which can be written by our or +and most are elements from s or do these + + align:start position:0% +and most are elements from s or do these + + + align:start position:0% +and most are elements from s or do these +elements look like what do you think + + align:start position:0% +elements look like what do you think + + + align:start position:0% +elements look like what do you think +right so if you look at elements in here + + align:start position:0% +right so if you look at elements in here + + + align:start position:0% +right so if you look at elements in here +how large can this entry the 1 comma 2 + + align:start position:0% +how large can this entry the 1 comma 2 + + + align:start position:0% +how large can this entry the 1 comma 2 +entry be each time you do addition so + + align:start position:0% +entry be each time you do addition so + + + align:start position:0% +entry be each time you do addition so +it's a most art ok so let me be a bit + + align:start position:0% +it's a most art ok so let me be a bit + + + align:start position:0% +it's a most art ok so let me be a bit +rough here and say it's Big O of are and + + align:start position:0% +rough here and say it's Big O of are and + + + align:start position:0% +rough here and say it's Big O of are and +likewise the 2 1 2 3 entries also Big O + + align:start position:0% +likewise the 2 1 2 3 entries also Big O + + + align:start position:0% +likewise the 2 1 2 3 entries also Big O +of our what about the top right entry + + align:start position:0% +of our what about the top right entry + + + align:start position:0% +of our what about the top right entry +over here yeah so it grows like R + + align:start position:0% +over here yeah so it grows like R + + + align:start position:0% +over here yeah so it grows like R +squared because there's an extra + + align:start position:0% +squared because there's an extra + + + align:start position:0% +squared because there's an extra +multiplication term ok so you can be + + align:start position:0% +multiplication term ok so you can be + + + align:start position:0% +multiplication term ok so you can be +much more precise about the growth rate + + align:start position:0% +much more precise about the growth rate + + + align:start position:0% +much more precise about the growth rate +of these individual entries but very + + align:start position:0% +of these individual entries but very + + + align:start position:0% +of these individual entries but very +roughly it looks like this over here so + + align:start position:0% +roughly it looks like this over here so + + + align:start position:0% +roughly it looks like this over here so +the size of s are all of s is roughly on + + align:start position:0% +the size of s are all of s is roughly on + + + align:start position:0% +the size of s are all of s is roughly on +the order of fourth power of our + + align:start position:0% +the order of fourth power of our + + + align:start position:0% +the order of fourth power of our +so in particular the doubling constant + + align:start position:0% + + + + align:start position:0% + +ours will be large is what happens we go + + align:start position:0% +ours will be large is what happens we go + + + align:start position:0% +ours will be large is what happens we go +from r2 to r2 the size increases by a + + align:start position:0% +from r2 to r2 the size increases by a + + + align:start position:0% +from r2 to r2 the size increases by a +factor of around 16 okay so that's an + + align:start position:0% +factor of around 16 okay so that's an + + + align:start position:0% +factor of around 16 okay so that's an +example of a set in a non abelian group + + align:start position:0% +example of a set in a non abelian group + + + align:start position:0% +example of a set in a non abelian group +with founded doubly which is genuinely + + align:start position:0% +with founded doubly which is genuinely + + + align:start position:0% +with founded doubly which is genuinely +different from the examples we have seen + + align:start position:0% +different from the examples we have seen + + + align:start position:0% +different from the examples we have seen +so far right so that's non abelian + + align:start position:0% + + + + align:start position:0% + +questions oh it's a size we've shown the + + align:start position:0% +questions oh it's a size we've shown the + + + align:start position:0% +questions oh it's a size we've shown the +sizes I'm not being very precise here + + align:start position:0% +sizes I'm not being very precise here + + + align:start position:0% +sizes I'm not being very precise here +but you can do upper bound and lower + + align:start position:0% +but you can do upper bound and lower + + + align:start position:0% +but you can do upper bound and lower +bound so it sighs turns out to be the + + align:start position:0% +bound so it sighs turns out to be the + + + align:start position:0% +bound so it sighs turns out to be the +water of our to the form so you want to + + align:start position:0% +water of our to the form so you want to + + + align:start position:0% +water of our to the form so you want to +show that there are actually enough + + align:start position:0% +show that there are actually enough + + + align:start position:0% +show that there are actually enough +elements over here that you can fill in + + align:start position:0% +elements over here that you can fill in + + + align:start position:0% +elements over here that you can fill in +but I'll be okay can you build other + + align:start position:0% +but I'll be okay can you build other + + + align:start position:0% +but I'll be okay can you build other +examples like this one + + align:start position:0% + + + + align:start position:0% + +okay questions how do we know this isn't + + align:start position:0% +okay questions how do we know this isn't + + + align:start position:0% +okay questions how do we know this isn't +like a cassette some a cassette + + align:start position:0% +like a cassette some a cassette + + + align:start position:0% +like a cassette some a cassette +progression of one thing this is not a + + align:start position:0% +progression of one thing this is not a + + + align:start position:0% +progression of one thing this is not a +billion s if you multiply entries of s + + align:start position:0% +billion s if you multiply entries of s + + + align:start position:0% +billion s if you multiply entries of s +in different waters you get different + + align:start position:0% +in different waters you get different + + + align:start position:0% +in different waters you get different +elements so in already in that way it's + + align:start position:0% +elements so in already in that way it's + + + align:start position:0% +elements so in already in that way it's +different from the examples that we have + + align:start position:0% +different from the examples that we have + + + align:start position:0% +different from the examples that we have +seen before + + align:start position:0% +seen before + + + align:start position:0% +seen before +but no you're right so maybe we can + + align:start position:0% +but no you're right so maybe we can + + + align:start position:0% +but no you're right so maybe we can +write this a semi direct product in + + align:start position:0% +write this a semi direct product in + + + align:start position:0% +write this a semi direct product in +terms of things we have seen before and + + align:start position:0% +terms of things we have seen before and + + + align:start position:0% +terms of things we have seen before and +it is in some sense a semi direct + + align:start position:0% +it is in some sense a semi direct + + + align:start position:0% +it is in some sense a semi direct +product but it's a very special kind of + + align:start position:0% +product but it's a very special kind of + + + align:start position:0% +product but it's a very special kind of +semi direct product okay from that + + align:start position:0% +semi direct product okay from that + + + align:start position:0% +semi direct product okay from that +example you can build bigger examples of + + align:start position:0% +example you can build bigger examples of + + + align:start position:0% +example you can build bigger examples of +course with more entries in the matrix + + align:start position:0% +course with more entries in the matrix + + + align:start position:0% +course with more entries in the matrix +but more generally these things are what + + align:start position:0% +but more generally these things are what + + + align:start position:0% +but more generally these things are what +are known as neo potent groups right so + + align:start position:0% +are known as neo potent groups right so + + + align:start position:0% +are known as neo potent groups right so +there's an example important group and + + align:start position:0% +there's an example important group and + + + align:start position:0% +there's an example important group and +remind you the definition of a new Putin + + align:start position:0% +remind you the definition of a new Putin + + + align:start position:0% +remind you the definition of a new Putin +group is a group where the lower central + + align:start position:0% +group is a group where the lower central + + + align:start position:0% +group is a group where the lower central +series eventually terminates if you look + + align:start position:0% +series eventually terminates if you look + + + align:start position:0% +series eventually terminates if you look +hard so this is the commutator of G look + + align:start position:0% +hard so this is the commutator of G look + + + align:start position:0% +hard so this is the commutator of G look +at all the elements within s XY X + + align:start position:0% +at all the elements within s XY X + + + align:start position:0% +at all the elements within s XY X +inverse Y inverse set of elements that + + align:start position:0% +inverse Y inverse set of elements that + + + align:start position:0% +inverse Y inverse set of elements that +can be written this way so that's a + + align:start position:0% +can be written this way so that's a + + + align:start position:0% +can be written this way so that's a +subgroup and if I repeat this operation + + align:start position:0% + + + + align:start position:0% + +enough times I eventually would get just + + align:start position:0% +enough times I eventually would get just + + + align:start position:0% +enough times I eventually would get just +the identity and you could try it on + + align:start position:0% +the identity and you could try it on + + + align:start position:0% +the identity and you could try it on +that group if you do the commutator okay + + align:start position:0% +that group if you do the commutator okay + + + align:start position:0% +that group if you do the commutator okay +so you essentially you get rid of a + + align:start position:0% +so you essentially you get rid of a + + + align:start position:0% +so you essentially you get rid of a +billion Asst and you move up the Hodag + + align:start position:0% +billion Asst and you move up the Hodag + + + align:start position:0% +billion Asst and you move up the Hodag +you know + + align:start position:0% +you know + + + align:start position:0% +you know +take a commentator you get rid of this + + align:start position:0% +take a commentator you get rid of this + + + align:start position:0% +take a commentator you get rid of this +you zero out these two entries together + + align:start position:0% +you zero out these two entries together + + + align:start position:0% +you zero out these two entries together +Z alone if you do it one more time you + + align:start position:0% +Z alone if you do it one more time you + + + align:start position:0% +Z alone if you do it one more time you +zero out that entry and so more + + align:start position:0% +zero out that entry and so more + + + align:start position:0% +zero out that entry and so more +generally all of these new potent groups + + align:start position:0% + + + + align:start position:0% + +so if you take set of generators and + + align:start position:0% +so if you take set of generators and + + + align:start position:0% +so if you take set of generators and +look at all + + align:start position:0% +look at all + + + align:start position:0% +look at all +and look at the volume of all ha there's + + align:start position:0% +and look at the volume of all ha there's + + + align:start position:0% +and look at the volume of all ha there's +a volume of the bulk grow with the + + align:start position:0% +a volume of the bulk grow with the + + + align:start position:0% +a volume of the bulk grow with the +radius it grows like a polynomial and so + + align:start position:0% +radius it grows like a polynomial and so + + + align:start position:0% +radius it grows like a polynomial and so +let me define that + + align:start position:0% +let me define that + + + align:start position:0% +let me define that +so given G a finitely generated coop so + + align:start position:0% +so given G a finitely generated coop so + + + align:start position:0% +so given G a finitely generated coop so +generated by s we say that G has + + align:start position:0% +generated by s we say that G has + + + align:start position:0% +generated by s we say that G has +polynomial growth if the size has to be + + align:start position:0% +polynomial growth if the size has to be + + + align:start position:0% +polynomial growth if the size has to be +our growth like at most a polynomial in + + align:start position:0% +our growth like at most a polynomial in + + + align:start position:0% +our growth like at most a polynomial in +R it's worth noting that this definition + + align:start position:0% +R it's worth noting that this definition + + + align:start position:0% +R it's worth noting that this definition +is really a definition about G it does + + align:start position:0% +is really a definition about G it does + + + align:start position:0% +is really a definition about G it does +not depend on the choice of generators + + align:start position:0% + + + + align:start position:0% + +you have different choices generators + + align:start position:0% +you have different choices generators + + + align:start position:0% +you have different choices generators +for the group but polynomial growth with + + align:start position:0% +for the group but polynomial growth with + + + align:start position:0% +for the group but polynomial growth with +respect to one set of generators then + + align:start position:0% +respect to one set of generators then + + + align:start position:0% +respect to one set of generators then +it's the same it's also has polynomial + + align:start position:0% +it's the same it's also has polynomial + + + align:start position:0% +it's the same it's also has polynomial +growth with regards to every other set + + align:start position:0% +growth with regards to every other set + + + align:start position:0% +growth with regards to every other set +so we've seen an example of groups with + + align:start position:0% +so we've seen an example of groups with + + + align:start position:0% +so we've seen an example of groups with +polynomial growth abelian groups have + + align:start position:0% +polynomial growth abelian groups have + + + align:start position:0% +polynomial growth abelian groups have +polynomial growth okay so if you think a + + align:start position:0% +polynomial growth okay so if you think a + + + align:start position:0% +polynomial growth okay so if you think a +polynomial thing you know lattice Z to + + align:start position:0% +polynomial thing you know lattice Z to + + + align:start position:0% +polynomial thing you know lattice Z to +the N take a ball growing so it has size + + align:start position:0% +the N take a ball growing so it has size + + + align:start position:0% +the N take a ball growing so it has size +growing like + + align:start position:0% +growing like + + + align:start position:0% +growing like +are to the dimension but no potent group + + align:start position:0% +are to the dimension but no potent group + + + align:start position:0% +are to the dimension but no potent group +is another example of groups with + + align:start position:0% +is another example of groups with + + + align:start position:0% +is another example of groups with +polynomial growth you may want to and + + align:start position:0% +polynomial growth you may want to and + + + align:start position:0% +polynomial growth you may want to and +these are intuitive theories for now + + align:start position:0% +these are intuitive theories for now + + + align:start position:0% +these are intuitive theories for now +related you found the table the + + align:start position:0% +related you found the table the + + + align:start position:0% +related you found the table the +polynomial Coughlin has found a doubling + + align:start position:0% +polynomial Coughlin has found a doubling + + + align:start position:0% +polynomial Coughlin has found a doubling +so is there a classification of groups + + align:start position:0% +so is there a classification of groups + + + align:start position:0% +so is there a classification of groups +with bound with polynomial growth so if + + align:start position:0% +with bound with polynomial growth so if + + + align:start position:0% +with bound with polynomial growth so if +I tell you a group so infinite group + + align:start position:0% +I tell you a group so infinite group + + + align:start position:0% +I tell you a group so infinite group +always because other ways finite then + + align:start position:0% +always because other ways finite then + + + align:start position:0% +always because other ways finite then +maxes out already at some point so I + + align:start position:0% +maxes out already at some point so I + + + align:start position:0% +maxes out already at some point so I +give you an infinite group I tell you + + align:start position:0% +give you an infinite group I tell you + + + align:start position:0% +give you an infinite group I tell you +has polynomial growth what can you tell + + align:start position:0% +has polynomial growth what can you tell + + + align:start position:0% +has polynomial growth what can you tell +me about this group is there some + + align:start position:0% +me about this group is there some + + + align:start position:0% +me about this group is there some +characterization that's an inverse of + + align:start position:0% +characterization that's an inverse of + + + align:start position:0% +characterization that's an inverse of +what we've seen so far and the answer is + + align:start position:0% +what we've seen so far and the answer is + + + align:start position:0% +what we've seen so far and the answer is +yes and this is a famous and deep result + + align:start position:0% +yes and this is a famous and deep result + + + align:start position:0% +yes and this is a famous and deep result +of robot so chromis theorem polynomial + + align:start position:0% + + + + align:start position:0% + +from the 80s romoff showed that a finely + + align:start position:0% +from the 80s romoff showed that a finely + + + align:start position:0% +from the 80s romoff showed that a finely +generated virtually new poll where + + align:start position:0% +generated virtually new poll where + + + align:start position:0% +generated virtually new poll where +virtually is an adverb in group theory + + align:start position:0% +virtually is an adverb in group theory + + + align:start position:0% +virtually is an adverb in group theory +when you have some property like a + + align:start position:0% +when you have some property like a + + + align:start position:0% +when you have some property like a +billion or solvable or whatever so new + + align:start position:0% +billion or solvable or whatever so new + + + align:start position:0% +billion or solvable or whatever so new +virtually P means that there exists a + + align:start position:0% +virtually P means that there exists a + + + align:start position:0% +virtually P means that there exists a +finite index subject with property P so + + align:start position:0% +finite index subject with property P so + + + align:start position:0% +finite index subject with property P so +virtually no Putin is that there's a + + align:start position:0% +virtually no Putin is that there's a + + + align:start position:0% +virtually no Putin is that there's a +finite index subgroup that is no potent + + align:start position:0% +finite index subgroup that is no potent + + + align:start position:0% +finite index subgroup that is no potent +so it completely characterizes groups of + + align:start position:0% +so it completely characterizes groups of + + + align:start position:0% +so it completely characterizes groups of +polynomial growth so basically all the + + align:start position:0% +polynomial growth so basically all the + + + align:start position:0% +polynomial growth so basically all the +examples we've seen so far are + + align:start position:0% +examples we've seen so far are + + + align:start position:0% +examples we've seen so far are +representatives so up to changing by a + + align:start position:0% +representatives so up to changing by a + + + align:start position:0% +representatives so up to changing by a +finite index subgroup + + align:start position:0% +finite index subgroup + + + align:start position:0% +finite index subgroup +expect shouldn't change the growth + + align:start position:0% +expect shouldn't change the growth + + + align:start position:0% +expect shouldn't change the growth +nature by so much there are some + + align:start position:0% +nature by so much there are some + + + align:start position:0% +nature by so much there are some +analogies to be made here with for + + align:start position:0% +analogies to be made here with for + + + align:start position:0% +analogies to be made here with for +example in geometry you ask in Euclidean + + align:start position:0% +example in geometry you ask in Euclidean + + + align:start position:0% +example in geometry you ask in Euclidean +space how fast is the ball of radius R + + align:start position:0% +space how fast is the ball of radius R + + + align:start position:0% +space how fast is the ball of radius R +grown in dimension T it grows like R to + + align:start position:0% +grown in dimension T it grows like R to + + + align:start position:0% +grown in dimension T it grows like R to +the D what about in the hyperbolic space + + align:start position:0% +the D what about in the hyperbolic space + + + align:start position:0% +the D what about in the hyperbolic space +does anyone know how fast in hyperbolic + + align:start position:0% +does anyone know how fast in hyperbolic + + + align:start position:0% +does anyone know how fast in hyperbolic +space ball of radius R grows it's + + align:start position:0% +space ball of radius R grows it's + + + align:start position:0% +space ball of radius R grows it's +exponential in the radius so for now + + align:start position:0% +exponential in the radius so for now + + + align:start position:0% +exponential in the radius so for now +negatively curved spaces the boss grow + + align:start position:0% +negatively curved spaces the boss grow + + + align:start position:0% +negatively curved spaces the boss grow +polynomially but for something that's + + align:start position:0% +polynomially but for something that's + + + align:start position:0% +polynomially but for something that's +negatively curvature in particular the + + align:start position:0% +negatively curvature in particular the + + + align:start position:0% +negatively curvature in particular the +hyperbolic space the ball growth might + + align:start position:0% +hyperbolic space the ball growth might + + + align:start position:0% +hyperbolic space the ball growth might +be exponential you have a similar + + align:start position:0% +be exponential you have a similar + + + align:start position:0% +be exponential you have a similar +phenomenon happening here the opposite + + align:start position:0% +phenomenon happening here the opposite + + + align:start position:0% +phenomenon happening here the opposite +of polynomial growth is super polynomial + + align:start position:0% +of polynomial growth is super polynomial + + + align:start position:0% +of polynomial growth is super polynomial +growth but one specific example is that + + align:start position:0% +growth but one specific example is that + + + align:start position:0% +growth but one specific example is that +of a free group where there are no + + align:start position:0% +of a free group where there are no + + + align:start position:0% +of a free group where there are no +relations between the generators in that + + align:start position:0% +relations between the generators in that + + + align:start position:0% +relations between the generators in that +case the balls they grow like + + align:start position:0% + + + + align:start position:0% + +exponentially the all-school + + align:start position:0% +exponentially the all-school + + + align:start position:0% +exponentially the all-school +exponentially in the radius groom offs + + align:start position:0% +exponentially in the radius groom offs + + + align:start position:0% +exponentially in the radius groom offs +there is a deep theorem and it's + + align:start position:0% +there is a deep theorem and it's + + + align:start position:0% +there is a deep theorem and it's +original proof used some very hard tools + + align:start position:0% +original proof used some very hard tools + + + align:start position:0% +original proof used some very hard tools +coming from geometry and Gromov + + align:start position:0% +coming from geometry and Gromov + + + align:start position:0% +coming from geometry and Gromov +developed a notion of convergence of + + align:start position:0% +developed a notion of convergence of + + + align:start position:0% +developed a notion of convergence of +metric spaces somewhat akin to our + + align:start position:0% +metric spaces somewhat akin to our + + + align:start position:0% +metric spaces somewhat akin to our +discussion of graph limits so starting + + align:start position:0% +discussion of graph limits so starting + + + align:start position:0% +discussion of graph limits so starting +with discrete objects you looked at some + + align:start position:0% +with discrete objects you looked at some + + + align:start position:0% +with discrete objects you looked at some +convergence to some continuous objects + + align:start position:0% +convergence to some continuous objects + + + align:start position:0% +convergence to some continuous objects +and then used some very deep results + + align:start position:0% +and then used some very deep results + + + align:start position:0% +and then used some very deep results +from the classification of locally + + align:start position:0% +from the classification of locally + + + align:start position:0% +from the classification of locally +compact groups to derive this result + + align:start position:0% +compact groups to derive this result + + + align:start position:0% +compact groups to derive this result +over here + + align:start position:0% + + + + align:start position:0% + +so this proof has been quite influential + + align:start position:0% +so this proof has been quite influential + + + align:start position:0% +so this proof has been quite influential +and it's related to something called + + align:start position:0% +and it's related to something called + + + align:start position:0% +and it's related to something called +Hilbert's fifth problem which concern + + align:start position:0% +Hilbert's fifth problem which concern + + + align:start position:0% +Hilbert's fifth problem which concern +characterizations of B groups inverse + + align:start position:0% +characterizations of B groups inverse + + + align:start position:0% +characterizations of B groups inverse +high problems and tell you some + + align:start position:0% +high problems and tell you some + + + align:start position:0% +high problems and tell you some +structure has some property describe + + align:start position:0% +structure has some property describe + + + align:start position:0% +structure has some property describe +that structure okay what does this all + + align:start position:0% +that structure okay what does this all + + + align:start position:0% +that structure okay what does this all +have to do with fragments theorem + + align:start position:0% +have to do with fragments theorem + + + align:start position:0% +have to do with fragments theorem +well already you see some relation right + + align:start position:0% +well already you see some relation right + + + align:start position:0% +well already you see some relation right +so there seemed at least intuitively + + align:start position:0% +so there seemed at least intuitively + + + align:start position:0% +so there seemed at least intuitively +some relationship between groups of + + align:start position:0% +some relationship between groups of + + + align:start position:0% +some relationship between groups of +polynomial growth versus subsets have + + align:start position:0% +polynomial growth versus subsets have + + + align:start position:0% +polynomial growth versus subsets have +found the doubling a one implies the + + align:start position:0% +found the doubling a one implies the + + + align:start position:0% +found the doubling a one implies the +other although not in the converse and + + align:start position:0% +other although not in the converse and + + + align:start position:0% +other although not in the converse and +they are indeed we dated and this comes + + align:start position:0% +they are indeed we dated and this comes + + + align:start position:0% +they are indeed we dated and this comes +out of some very recent work oh I should + + align:start position:0% +out of some very recent work oh I should + + + align:start position:0% +out of some very recent work oh I should +also mention that Cuomo's theorem has + + align:start position:0% +also mention that Cuomo's theorem has + + + align:start position:0% +also mention that Cuomo's theorem has +been major simplified by kleiner who + + align:start position:0% +been major simplified by kleiner who + + + align:start position:0% +been major simplified by kleiner who +gave an important simplification more + + align:start position:0% +gave an important simplification more + + + align:start position:0% +gave an important simplification more +elementary proof of grow MOFs + + align:start position:0% +elementary proof of grow MOFs + + + align:start position:0% +elementary proof of grow MOFs +theorem okay so let's talk about a non + + align:start position:0% +theorem okay so let's talk about a non + + + align:start position:0% +theorem okay so let's talk about a non +abelian version of Fryman still we would + + align:start position:0% +abelian version of Fryman still we would + + + align:start position:0% +abelian version of Fryman still we would +like some result that says that it's a + + align:start position:0% +like some result that says that it's a + + + align:start position:0% +like some result that says that it's a +true that every set must every set so + + align:start position:0% +true that every set must every set so + + + align:start position:0% +true that every set must every set so +previously we had a small table you want + + align:start position:0% +previously we had a small table you want + + + align:start position:0% +previously we had a small table you want +to have some similar notion although it + + align:start position:0% +to have some similar notion although it + + + align:start position:0% +to have some similar notion although it +might not be exactly small doubling but + + align:start position:0% +might not be exactly small doubling but + + + align:start position:0% +might not be exactly small doubling but +let me not be very precise and to say + + align:start position:0% +let me not be very precise and to say + + + align:start position:0% +let me not be very precise and to say +hold small doubling in literature these + + align:start position:0% +hold small doubling in literature these + + + align:start position:0% +hold small doubling in literature these +things are sometimes also known as + + align:start position:0% +things are sometimes also known as + + + align:start position:0% +things are sometimes also known as +approximate groups you catch the + + align:start position:0% +approximate groups you catch the + + + align:start position:0% +approximate groups you catch the +relevant literature on this subject most + + align:start position:0% +relevant literature on this subject most + + + align:start position:0% +relevant literature on this subject most +every set of small doubling in some non + + align:start position:0% +every set of small doubling in some non + + + align:start position:0% +every set of small doubling in some non +abelian group behave like one of these + + align:start position:0% +abelian group behave like one of these + + + align:start position:0% +abelian group behave like one of these +known examples something which is some + + align:start position:0% +known examples something which is some + + + align:start position:0% +known examples something which is some +combination + + align:start position:0% + + + + align:start position:0% + +of subgroups and no potent balls so + + align:start position:0% +of subgroups and no potent balls so + + + align:start position:0% +of subgroups and no potent balls so +these combinations are sometimes known + + align:start position:0% +these combinations are sometimes known + + + align:start position:0% +these combinations are sometimes known +as Cosette Neal progressions so this was + + align:start position:0% +as Cosette Neal progressions so this was + + + align:start position:0% +as Cosette Neal progressions so this was +very this was something that was only + + align:start position:0% +very this was something that was only + + + align:start position:0% +very this was something that was only +explore in the past ten years or so and + + align:start position:0% +explore in the past ten years or so and + + + align:start position:0% +explore in the past ten years or so and +a series of very difficult works + + align:start position:0% +a series of very difficult works + + + align:start position:0% +a series of very difficult works +previously have been known and still + + align:start position:0% +previously have been known and still + + + align:start position:0% +previously have been known and still +it's being investigated for various + + align:start position:0% +it's being investigated for various + + + align:start position:0% +it's being investigated for various +special classes of matrix groups or + + align:start position:0% +special classes of matrix groups or + + + align:start position:0% +special classes of matrix groups or +special classes of groups like solve a + + align:start position:0% +special classes of groups like solve a + + + align:start position:0% +special classes of groups like solve a +group solvable groups and whatnot that + + align:start position:0% +group solvable groups and whatnot that + + + align:start position:0% +group solvable groups and whatnot that +are more explicit or easier to handle or + + align:start position:0% +are more explicit or easier to handle or + + + align:start position:0% +are more explicit or easier to handle or +closer to the abelian analog there was + + align:start position:0% +closer to the abelian analog there was + + + align:start position:0% +closer to the abelian analog there was +important work of push off scheme which + + align:start position:0% +important work of push off scheme which + + + align:start position:0% +important work of push off scheme which +was published about ten years ago who + + align:start position:0% +was published about ten years ago who + + + align:start position:0% +was published about ten years ago who +showed using model theory techniques so + + align:start position:0% +showed using model theory techniques so + + + align:start position:0% +showed using model theory techniques so +using methods from logic that a weak + + align:start position:0% +using methods from logic that a weak + + + align:start position:0% +using methods from logic that a weak +version of Freeman's theorem is true and + + align:start position:0% +version of Freeman's theorem is true and + + + align:start position:0% +version of Freeman's theorem is true and +later on + + align:start position:0% +later on + + + align:start position:0% +later on +Priya green and hell building on + + align:start position:0% +Priya green and hell building on + + + align:start position:0% +Priya green and hell building on +Kirchhoff's kiss work so this actually + + align:start position:0% +Kirchhoff's kiss work so this actually + + + align:start position:0% +Kirchhoff's kiss work so this actually +came quite a bit later even though the + + align:start position:0% +came quite a bit later even though the + + + align:start position:0% +came quite a bit later even though the +journal publication dates are the same + + align:start position:0% +journal publication dates are the same + + + align:start position:0% +journal publication dates are the same +year so they were able to build on + + align:start position:0% +year so they were able to build on + + + align:start position:0% +year so they were able to build on +Kirchhoff's keys work and but greatly + + align:start position:0% +Kirchhoff's keys work and but greatly + + + align:start position:0% +Kirchhoff's keys work and but greatly +expanding on it and going back to some + + align:start position:0% +expanding on it and going back to some + + + align:start position:0% +expanding on it and going back to some +of the older techniques coming from + + align:start position:0% +of the older techniques coming from + + + align:start position:0% +of the older techniques coming from +Gilbert's fifth problem and as a result + + align:start position:0% +Gilbert's fifth problem and as a result + + + align:start position:0% +Gilbert's fifth problem and as a result +proved an inverse structure theorem that + + align:start position:0% +proved an inverse structure theorem that + + + align:start position:0% +proved an inverse structure theorem that +gave some kind of answer to this + + align:start position:0% +gave some kind of answer to this + + + align:start position:0% +gave some kind of answer to this +question of non abelian Fryman so we now + + align:start position:0% +question of non abelian Fryman so we now + + + align:start position:0% +question of non abelian Fryman so we now +do have some theorem which is like + + align:start position:0% +do have some theorem which is like + + + align:start position:0% +do have some theorem which is like +Fryman Sturm for abelian groups that + + align:start position:0% +Fryman Sturm for abelian groups that + + + align:start position:0% +Fryman Sturm for abelian groups that +says in a bit non abelian group if you + + align:start position:0% +says in a bit non abelian group if you + + + align:start position:0% +says in a bit non abelian group if you +have something that resembles small + + align:start position:0% +have something that resembles small + + + align:start position:0% +have something that resembles small +doubling then the set must in some sense + + align:start position:0% +doubling then the set must in some sense + + + align:start position:0% +doubling then the set must in some sense +look like a combination + + align:start position:0% +look like a combination + + + align:start position:0% +look like a combination +of subgroups and neo potent boss but let + + align:start position:0% +of subgroups and neo potent boss but let + + + align:start position:0% +of subgroups and neo potent boss but let +me not be precise at all the methods + + align:start position:0% +me not be precise at all the methods + + + align:start position:0% +me not be precise at all the methods +here build on Kirchhoff's key and which + + align:start position:0% +here build on Kirchhoff's key and which + + + align:start position:0% +here build on Kirchhoff's key and which +also used model theory which is kind of + + align:start position:0% +also used model theory which is kind of + + + align:start position:0% +also used model theory which is kind of +I mean it's something we're okay in + + align:start position:0% +I mean it's something we're okay in + + + align:start position:0% +I mean it's something we're okay in +particular one feature of all of these + + align:start position:0% +particular one feature of all of these + + + align:start position:0% +particular one feature of all of these +proofs is that they give no bounds + + align:start position:0% + + + + align:start position:0% + +similar to what we seen earlier in the + + align:start position:0% +similar to what we seen earlier in the + + + align:start position:0% +similar to what we seen earlier in the +course improves our involved compactness + + align:start position:0% +course improves our involved compactness + + + align:start position:0% +course improves our involved compactness +what happens here is that the arguments + + align:start position:0% +what happens here is that the arguments + + + align:start position:0% +what happens here is that the arguments +use ultra filters so there are these + + align:start position:0% +use ultra filters so there are these + + + align:start position:0% +use ultra filters so there are these +constructions from mathematical logic + + align:start position:0% +constructions from mathematical logic + + + align:start position:0% +constructions from mathematical logic +and like compactness they give no bats + + align:start position:0% +and like compactness they give no bats + + + align:start position:0% +and like compactness they give no bats +so it remains an open problem to proof + + align:start position:0% +so it remains an open problem to proof + + + align:start position:0% +so it remains an open problem to proof +Fryman stands for non abelian groups + + align:start position:0% +Fryman stands for non abelian groups + + + align:start position:0% +Fryman stands for non abelian groups +with some concrete bands question so + + align:start position:0% +with some concrete bands question so + + + align:start position:0% +with some concrete bands question so +what is new potent bomb I wouldn't want + + align:start position:0% +what is new potent bomb I wouldn't want + + + align:start position:0% +what is new potent bomb I wouldn't want +to give a precise definition but roughly + + align:start position:0% +to give a precise definition but roughly + + + align:start position:0% +to give a precise definition but roughly +speaking it's balls that come out of + + align:start position:0% +speaking it's balls that come out of + + + align:start position:0% +speaking it's balls that come out of +those types of constructions right so + + align:start position:0% +those types of constructions right so + + + align:start position:0% +those types of constructions right so +you take a new potent subgroup you take + + align:start position:0% +you take a new potent subgroup you take + + + align:start position:0% +you take a new potent subgroup you take +an important group you look at the image + + align:start position:0% +an important group you look at the image + + + align:start position:0% +an important group you look at the image +when you're potent group into your group + + align:start position:0% +when you're potent group into your group + + + align:start position:0% +when you're potent group into your group +and then look at the image of that ball + + align:start position:0% + + + + align:start position:0% + +so something that looks like one of the + + align:start position:0% +so something that looks like one of the + + + align:start position:0% +so something that looks like one of the +previous constructions okay so that's + + align:start position:0% +previous constructions okay so that's + + + align:start position:0% +previous constructions okay so that's +all I want to say about non abelian + + align:start position:0% +all I want to say about non abelian + + + align:start position:0% +all I want to say about non abelian +extensions are fragments theorem any + + align:start position:0% +extensions are fragments theorem any + + + align:start position:0% +extensions are fragments theorem any +questions okay so what I mean by so you + + align:start position:0% +questions okay so what I mean by so you + + + align:start position:0% +questions okay so what I mean by so you +can look in the papers to see the + + align:start position:0% +can look in the papers to see the + + + align:start position:0% +can look in the papers to see the +precise definitions but roughly speaking + + align:start position:0% +precise definitions but roughly speaking + + + align:start position:0% +precise definitions but roughly speaking +it's that if you have therefore one + + align:start position:0% +it's that if you have therefore one + + + align:start position:0% +it's that if you have therefore one +there are different kinds of definitions + + align:start position:0% +there are different kinds of definitions + + + align:start position:0% +there are different kinds of definitions +and most of them are equivalent but one + + align:start position:0% +and most of them are equivalent but one + + + align:start position:0% +and most of them are equivalent but one +versions that you have a set a such that + + align:start position:0% +versions that you have a set a such that + + + align:start position:0% +versions that you have a set a such that +a a is coverable by hey + + align:start position:0% + + + + align:start position:0% + +so to bid more than just the size + + align:start position:0% +so to bid more than just the size + + + align:start position:0% +so to bid more than just the size +information but it's actually related to + + align:start position:0% +information but it's actually related to + + + align:start position:0% +information but it's actually related to +size information so we've already seen + + align:start position:0% +size information so we've already seen + + + align:start position:0% +size information so we've already seen +its course how many of these different + + align:start position:0% +its course how many of these different + + + align:start position:0% +its course how many of these different +notions you can go back and forth from + + align:start position:0% +notions you can go back and forth from + + + align:start position:0% +notions you can go back and forth from +one to the other I'm covering two to + + align:start position:0% +one to the other I'm covering two to + + + align:start position:0% +one to the other I'm covering two to +size and whatnot okay + + align:start position:0% +size and whatnot okay + + + align:start position:0% +size and whatnot okay +the final thing I want to discuss today + + align:start position:0% +the final thing I want to discuss today + + + align:start position:0% +the final thing I want to discuss today +is one of the most central open problems + + align:start position:0% +is one of the most central open problems + + + align:start position:0% +is one of the most central open problems +in additive combinatorics going back to + + align:start position:0% +in additive combinatorics going back to + + + align:start position:0% +in additive combinatorics going back to +the abelian version so this is known as + + align:start position:0% +the abelian version so this is known as + + + align:start position:0% +the abelian version so this is known as +the polynomial Fryman Rouge our + + align:start position:0% +the polynomial Fryman Rouge our + + + align:start position:0% +the polynomial Fryman Rouge our +conjecture + + align:start position:0% + + + + align:start position:0% + +so we would like some kind of a Fryman + + align:start position:0% +so we would like some kind of a Fryman + + + align:start position:0% +so we would like some kind of a Fryman +theorem that preserves the constants up + + align:start position:0% +theorem that preserves the constants up + + + align:start position:0% +theorem that preserves the constants up +to polynomial changes without losing an + + align:start position:0% +to polynomial changes without losing an + + + align:start position:0% +to polynomial changes without losing an +exponent from earlier discussions I + + align:start position:0% +exponent from earlier discussions I + + + align:start position:0% +exponent from earlier discussions I +showed you that the bounds that we + + align:start position:0% +showed you that the bounds that we + + + align:start position:0% +showed you that the bounds that we +almost proved is close to the truth you + + align:start position:0% +almost proved is close to the truth you + + + align:start position:0% +almost proved is close to the truth you +do need some kind of exponential loss in + + align:start position:0% +do need some kind of exponential loss in + + + align:start position:0% +do need some kind of exponential loss in +the blow-up size of the GA p but it + + align:start position:0% +the blow-up size of the GA p but it + + + align:start position:0% +the blow-up size of the GA p but it +turns out those kind of examples are + + align:start position:0% +turns out those kind of examples are + + + align:start position:0% +turns out those kind of examples are +slightly misleading all right so let's + + align:start position:0% +slightly misleading all right so let's + + + align:start position:0% +slightly misleading all right so let's +look at the examples the constructions + + align:start position:0% +look at the examples the constructions + + + align:start position:0% +look at the examples the constructions +again so if a so just for simplicity + + align:start position:0% +again so if a so just for simplicity + + + align:start position:0% +again so if a so just for simplicity +exposition I'm going to stick with f2 to + + align:start position:0% +exposition I'm going to stick with f2 to + + + align:start position:0% +exposition I'm going to stick with f2 to +the N at least initially so if a is an + + align:start position:0% +the N at least initially so if a is an + + + align:start position:0% +the N at least initially so if a is an +independent set of size and then okay + + align:start position:0% +independent set of size and then okay + + + align:start position:0% +independent set of size and then okay +being the doubling constant of a trophy + + align:start position:0% +being the doubling constant of a trophy + + + align:start position:0% +being the doubling constant of a trophy +like n over 2 and yet the subgroup that + + align:start position:0% +like n over 2 and yet the subgroup that + + + align:start position:0% +like n over 2 and yet the subgroup that +contains a size true to be something on + + align:start position:0% +contains a size true to be something on + + + align:start position:0% +contains a size true to be something on +the water okay times hey so you + + align:start position:0% +the water okay times hey so you + + + align:start position:0% +the water okay times hey so you +necessarily incur an exponential loss + + align:start position:0% +necessarily incur an exponential loss + + + align:start position:0% +necessarily incur an exponential loss +over here now you might complain what + + align:start position:0% +over here now you might complain what + + + align:start position:0% +over here now you might complain what +the size of a here is basically K but of + + align:start position:0% +the size of a here is basically K but of + + + align:start position:0% +the size of a here is basically K but of +course I can blow up this example by + + align:start position:0% +course I can blow up this example by + + + align:start position:0% +course I can blow up this example by +considering what happens if you take + + align:start position:0% +considering what happens if you take + + + align:start position:0% +considering what happens if you take +each element here + + align:start position:0% +each element here + + + align:start position:0% +each element here +into entire subspace so these are the + + align:start position:0% +into entire subspace so these are the + + + align:start position:0% +into entire subspace so these are the +coordinate vectors so now I'm sitting + + align:start position:0% +coordinate vectors so now I'm sitting + + + align:start position:0% +coordinate vectors so now I'm sitting +inside F 2 to the M plus N and that + + align:start position:0% +inside F 2 to the M plus N and that + + + align:start position:0% +inside F 2 to the M plus N and that +gives you this set the toppling constant + + align:start position:0% +gives you this set the toppling constant + + + align:start position:0% +gives you this set the toppling constant +is still the same as before and yet we + + align:start position:0% +is still the same as before and yet we + + + align:start position:0% +is still the same as before and yet we +see that the generated by a still has + + align:start position:0% +see that the generated by a still has + + + align:start position:0% +see that the generated by a still has +this exponential blow-up in this + + align:start position:0% +this exponential blow-up in this + + + align:start position:0% +this exponential blow-up in this +constant exponential in the doubling + + align:start position:0% +constant exponential in the doubling + + + align:start position:0% +constant exponential in the doubling +constant but now you see in this example + + align:start position:0% +constant but now you see in this example + + + align:start position:0% +constant but now you see in this example +here even though the subgroup generated + + align:start position:0% +here even though the subgroup generated + + + align:start position:0% +here even though the subgroup generated +by a can be much larger than a by so + + align:start position:0% +by a can be much larger than a by so + + + align:start position:0% +by a can be much larger than a by so +everything's still constant so much + + align:start position:0% +everything's still constant so much + + + align:start position:0% +everything's still constant so much +largest in terms of them as a function + + align:start position:0% +largest in terms of them as a function + + + align:start position:0% +largest in terms of them as a function +of the toppling constant a has a very + + align:start position:0% +of the toppling constant a has a very + + + align:start position:0% +of the toppling constant a has a very +large structure so a has contains a very + + align:start position:0% +large structure so a has contains a very + + + align:start position:0% +large structure so a has contains a very +large subspace subspace I mean a fine + + align:start position:0% +large subspace subspace I mean a fine + + + align:start position:0% +large subspace subspace I mean a fine +subspace and this subspace here is + + align:start position:0% +subspace and this subspace here is + + + align:start position:0% +subspace and this subspace here is +comparable to the size of a itself so + + align:start position:0% +comparable to the size of a itself so + + + align:start position:0% +comparable to the size of a itself so +you might wonder if you don't care about + + align:start position:0% +you might wonder if you don't care about + + + align:start position:0% +you might wonder if you don't care about +containing a inside a single subspace + + align:start position:0% +containing a inside a single subspace + + + align:start position:0% +containing a inside a single subspace +can you do much better in terms of + + align:start position:0% +can you do much better in terms of + + + align:start position:0% +can you do much better in terms of +bounds and that's the content of the + + align:start position:0% +bounds and that's the content of the + + + align:start position:0% +bounds and that's the content of the +polynomial frame intruder conjecture or + + align:start position:0% +polynomial frame intruder conjecture or + + + align:start position:0% +polynomial frame intruder conjecture or +conjecture for f2 to the M says that if + + align:start position:0% +conjecture for f2 to the M says that if + + + align:start position:0% +conjecture for f2 to the M says that if +you have a subset of f2 to the M and a + + align:start position:0% +you have a subset of f2 to the M and a + + + align:start position:0% +you have a subset of f2 to the M and a +plus a is size and most K times the size + + align:start position:0% +plus a is size and most K times the size + + + align:start position:0% +plus a is size and most K times the size +of a then there exists a subspace V of + + align:start position:0% +of a then there exists a subspace V of + + + align:start position:0% +of a then there exists a subspace V of +size at most + + align:start position:0% +size at most + + + align:start position:0% +size at most +such that the contains a large + + align:start position:0% +such that the contains a large + + + align:start position:0% +such that the contains a large +proportion and the large year we only + + align:start position:0% +proportion and the large year we only + + + align:start position:0% +proportion and the large year we only +lose something that is polynomial in + + align:start position:0% +lose something that is polynomial in + + + align:start position:0% +lose something that is polynomial in +these doubling constants so that's the + + align:start position:0% +these doubling constants so that's the + + + align:start position:0% +these doubling constants so that's the +case over here so instead of containing + + align:start position:0% +case over here so instead of containing + + + align:start position:0% +case over here so instead of containing +a in the inside an entire subspace + + align:start position:0% +a in the inside an entire subspace + + + align:start position:0% +a in the inside an entire subspace +I just want to contain a large fraction + + align:start position:0% +I just want to contain a large fraction + + + align:start position:0% +I just want to contain a large fraction +of a in a subspace and the conjecture is + + align:start position:0% +of a in a subspace and the conjecture is + + + align:start position:0% +of a in a subspace and the conjecture is +that I do not need to incur exponential + + align:start position:0% +that I do not need to incur exponential + + + align:start position:0% +that I do not need to incur exponential +losses in the constants question is V an + + align:start position:0% +losses in the constants question is V an + + + align:start position:0% +losses in the constants question is V an +affine subspace you can think of V s + + align:start position:0% +affine subspace you can think of V s + + + align:start position:0% +affine subspace you can think of V s +mattifying south chase you can think of + + align:start position:0% +mattifying south chase you can think of + + + align:start position:0% +mattifying south chase you can think of +V is a subspace it doesn't actually + + align:start position:0% +V is a subspace it doesn't actually + + + align:start position:0% +V is a subspace it doesn't actually +matter in this formulation okay + + align:start position:0% + + + + align:start position:0% + +there's an equivalent formulation which + + align:start position:0% +there's an equivalent formulation which + + + align:start position:0% +there's an equivalent formulation which +you might like better where initially my + + align:start position:0% +you might like better where initially my + + + align:start position:0% +you might like better where initially my +complaint well initially PFR is + + align:start position:0% +complaint well initially PFR is + + + align:start position:0% +complaint well initially PFR is +initially Fryman terms about covering it + + align:start position:0% +initially Fryman terms about covering it + + + align:start position:0% +initially Fryman terms about covering it +and now we've only covered a part of it + + align:start position:0% +and now we've only covered a part of it + + + align:start position:0% +and now we've only covered a part of it +of course we saw from earlier arguments + + align:start position:0% +of course we saw from earlier arguments + + + align:start position:0% +of course we saw from earlier arguments +you can use recovering lam article from + + align:start position:0% +you can use recovering lam article from + + + align:start position:0% +you can use recovering lam article from +covering a part of a to covering all of + + align:start position:0% +covering a part of a to covering all of + + + align:start position:0% +covering a part of a to covering all of +it + + align:start position:0% +it + + + align:start position:0% +it +indeed is this the case that this + + align:start position:0% +indeed is this the case that this + + + align:start position:0% +indeed is this the case that this +formulation is equivalent to the + + align:start position:0% +formulation is equivalent to the + + + align:start position:0% +formulation is equivalent to the +formulation that if a the same after the + + align:start position:0% +formulation that if a the same after the + + + align:start position:0% +formulation that if a the same after the +N and a plus a sighs the most K times a + + align:start position:0% +N and a plus a sighs the most K times a + + + align:start position:0% +N and a plus a sighs the most K times a +then there exists some subspace V with + + align:start position:0% +then there exists some subspace V with + + + align:start position:0% +then there exists some subspace V with +the size of e no larger than the size of + + align:start position:0% +the size of e no larger than the size of + + + align:start position:0% +the size of e no larger than the size of +a such that a can be covered by + + align:start position:0% +a such that a can be covered by + + + align:start position:0% +a such that a can be covered by +polynomial in K many Co sets we see that + + align:start position:0% +polynomial in K many Co sets we see that + + + align:start position:0% +polynomial in K many Co sets we see that +here here a has doubling constant K + + align:start position:0% +here here a has doubling constant K + + + align:start position:0% +here here a has doubling constant K +which is around the same as and and even + + align:start position:0% +which is around the same as and and even + + + align:start position:0% +which is around the same as and and even +though I cannot contain a by a single + + align:start position:0% +though I cannot contain a by a single + + + align:start position:0% +though I cannot contain a by a single +subspace of well fee the same size I can + + align:start position:0% +subspace of well fee the same size I can + + + align:start position:0% +subspace of well fee the same size I can +use K different translates to cover a + + align:start position:0% + + + + align:start position:0% + +any questions so I want to leave it to + + align:start position:0% +any questions so I want to leave it to + + + align:start position:0% +any questions so I want to leave it to +you as an exercise to prove that these + + align:start position:0% +you as an exercise to prove that these + + + align:start position:0% +you as an exercise to prove that these +two versions are equivalent to each + + align:start position:0% +two versions are equivalent to each + + + align:start position:0% +two versions are equivalent to each +other + + align:start position:0% +other + + + align:start position:0% +other +okay so it's not too hard so it's on + + align:start position:0% +okay so it's not too hard so it's on + + + align:start position:0% +okay so it's not too hard so it's on +something I have more time I would show + + align:start position:0% +something I have more time I would show + + + align:start position:0% +something I have more time I would show +you it's useless + + align:start position:0% +you it's useless + + + align:start position:0% +you it's useless +roots are covering lemma to prove this + + align:start position:0% +roots are covering lemma to prove this + + + align:start position:0% +roots are covering lemma to prove this +equivalence the nice thing about the + + align:start position:0% +equivalence the nice thing about the + + + align:start position:0% +equivalence the nice thing about the +poly no polynomial frame illusion + + align:start position:0% +poly no polynomial frame illusion + + + align:start position:0% +poly no polynomial frame illusion +conjecture pfr conjecture is considered + + align:start position:0% +conjecture pfr conjecture is considered + + + align:start position:0% +conjecture pfr conjecture is considered +a central conjecture in additive + + align:start position:0% +a central conjecture in additive + + + align:start position:0% +a central conjecture in additive +combinatorics because it has many + + align:start position:0% +combinatorics because it has many + + + align:start position:0% +combinatorics because it has many +equivalent formulation and relate to + + align:start position:0% +equivalent formulation and relate to + + + align:start position:0% +equivalent formulation and relate to +many problems that are central to the + + align:start position:0% +many problems that are central to the + + + align:start position:0% +many problems that are central to the +subject so we would like some kind of an + + align:start position:0% +subject so we would like some kind of an + + + align:start position:0% +subject so we would like some kind of an +inverse theorem that gives you these + + align:start position:0% +inverse theorem that gives you these + + + align:start position:0% +inverse theorem that gives you these +polynomial bounds and I'll mention a + + align:start position:0% +polynomial bounds and I'll mention a + + + align:start position:0% +polynomial bounds and I'll mention a +couple of these equivalent formulations + + align:start position:0% +couple of these equivalent formulations + + + align:start position:0% +couple of these equivalent formulations +here's an important formulation which is + + align:start position:0% +here's an important formulation which is + + + align:start position:0% +here's an important formulation which is +rather attractive where instead of + + align:start position:0% +rather attractive where instead of + + + align:start position:0% +rather attractive where instead of +considering subsets we're going to + + align:start position:0% +considering subsets we're going to + + + align:start position:0% +considering subsets we're going to +formulate something that has to do with + + align:start position:0% +formulate something that has to do with + + + align:start position:0% +formulate something that has to do with +approximate homomorphisms so the + + align:start position:0% +approximate homomorphisms so the + + + align:start position:0% +approximate homomorphisms so the +statements are still conjecture is that + + align:start position:0% +statements are still conjecture is that + + + align:start position:0% +statements are still conjecture is that +if it's a function from moving in space + + align:start position:0% +if it's a function from moving in space + + + align:start position:0% +if it's a function from moving in space +to another podium space is such that F + + align:start position:0% +to another podium space is such that F + + + align:start position:0% +to another podium space is such that F +is approximately a homomorphism in a + + align:start position:0% +is approximately a homomorphism in a + + + align:start position:0% +is approximately a homomorphism in a +sense that the set of possible errors if + + align:start position:0% +sense that the set of possible errors if + + + align:start position:0% +sense that the set of possible errors if +it's actually a homomorphism and this + + align:start position:0% +it's actually a homomorphism and this + + + align:start position:0% +it's actually a homomorphism and this +quantity is always equal to zero but + + align:start position:0% +quantity is always equal to zero but + + + align:start position:0% +quantity is always equal to zero but +it's approximately a whole more physical + + align:start position:0% +it's approximately a whole more physical + + + align:start position:0% +it's approximately a whole more physical +in the sense that the set of such errors + + align:start position:0% +in the sense that the set of such errors + + + align:start position:0% +in the sense that the set of such errors +is bounded by K in size the conclusion + + align:start position:0% +is bounded by K in size the conclusion + + + align:start position:0% +is bounded by K in size the conclusion +so the conjecture claims that then there + + align:start position:0% +so the conjecture claims that then there + + + align:start position:0% +so the conjecture claims that then there +exists an actual homomorphism an actual + + align:start position:0% +exists an actual homomorphism an actual + + + align:start position:0% +exists an actual homomorphism an actual +linear map + + align:start position:0% +linear map + + + align:start position:0% +linear map +G + + align:start position:0% + + + + align:start position:0% + +such that F is very close to G as in + + align:start position:0% +such that F is very close to G as in + + + align:start position:0% +such that F is very close to G as in +that the set of possible discrepancies + + align:start position:0% +that the set of possible discrepancies + + + align:start position:0% +that the set of possible discrepancies +between F and G yes Bank where you only + + align:start position:0% +between F and G yes Bank where you only + + + align:start position:0% +between F and G yes Bank where you only +lose a most polynomial in K so if you + + align:start position:0% +lose a most polynomial in K so if you + + + align:start position:0% +lose a most polynomial in K so if you +are an approximate homomorphism in this + + align:start position:0% +are an approximate homomorphism in this + + + align:start position:0% +are an approximate homomorphism in this +sense then you're actually very close to + + align:start position:0% +sense then you're actually very close to + + + align:start position:0% +sense then you're actually very close to +an actual linear map now it is not too + + align:start position:0% +an actual linear map now it is not too + + + align:start position:0% +an actual linear map now it is not too +hard to prove a much weaker + + align:start position:0% +hard to prove a much weaker + + + align:start position:0% +hard to prove a much weaker +quantitatively weaker version of the + + align:start position:0% +quantitatively weaker version of the + + + align:start position:0% +quantitatively weaker version of the +statement so I claim that it is trivial + + align:start position:0% +statement so I claim that it is trivial + + + align:start position:0% +statement so I claim that it is trivial +to show upper bound of at most two to + + align:start position:0% +to show upper bound of at most two to + + + align:start position:0% +to show upper bound of at most two to +the K over here so think about why so if + + align:start position:0% +the K over here so think about why so if + + + align:start position:0% +the K over here so think about why so if +I give you an F I can just think about + + align:start position:0% +I give you an F I can just think about + + + align:start position:0% +I give you an F I can just think about +what the values of F are on the basis + + align:start position:0% +what the values of F are on the basis + + + align:start position:0% +what the values of F are on the basis +and extend it to a linear map this set + + align:start position:0% +and extend it to a linear map this set + + + align:start position:0% +and extend it to a linear map this set +it's necessarily a span of that set so + + align:start position:0% +it's necessarily a span of that set so + + + align:start position:0% +it's necessarily a span of that set so +has size at most 2 to the K but it's + + align:start position:0% +has size at most 2 to the K but it's + + + align:start position:0% +has size at most 2 to the K but it's +open to show you only have to lose a + + align:start position:0% +open to show you only have to lose a + + + align:start position:0% +open to show you only have to lose a +polynomial in + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% + + + + align:start position:0% + +there's also a version of the polynomial + + align:start position:0% +there's also a version of the polynomial + + + align:start position:0% +there's also a version of the polynomial +frame illusion conjecture which is + + align:start position:0% +frame illusion conjecture which is + + + align:start position:0% +frame illusion conjecture which is +related to things we've discussed + + align:start position:0% +related to things we've discussed + + + align:start position:0% +related to things we've discussed +earlier regarding some Reddy's theorem + + align:start position:0% +earlier regarding some Reddy's theorem + + + align:start position:0% +earlier regarding some Reddy's theorem +and in fact the the polynomial Fryman + + align:start position:0% +and in fact the the polynomial Fryman + + + align:start position:0% +and in fact the the polynomial Fryman +Ruza conjecture kind of came back into + + align:start position:0% +Ruza conjecture kind of came back into + + + align:start position:0% +Ruza conjecture kind of came back into +popularity partly because of cowers + + align:start position:0% +popularity partly because of cowers + + + align:start position:0% +popularity partly because of cowers +proof of some rarities theorem that used + + align:start position:0% +proof of some rarities theorem that used + + + align:start position:0% +proof of some rarities theorem that used +many of these tools so let me state it + + align:start position:0% +many of these tools so let me state it + + + align:start position:0% +many of these tools so let me state it +here okay so we've seen some statement + + align:start position:0% +here okay so we've seen some statement + + + align:start position:0% +here okay so we've seen some statement +like this in an earlier lecture but but + + align:start position:0% +like this in an earlier lecture but but + + + align:start position:0% +like this in an earlier lecture but but +not very precisely not precisely in this + + align:start position:0% +not very precisely not precisely in this + + + align:start position:0% +not very precisely not precisely in this +form i won't define you all the notation + + align:start position:0% +form i won't define you all the notation + + + align:start position:0% +form i won't define you all the notation +here but hopefully you get a rough sense + + align:start position:0% +here but hopefully you get a rough sense + + + align:start position:0% +here but hopefully you get a rough sense +of what what it's about so we want some + + align:start position:0% +of what what it's about so we want some + + + align:start position:0% +of what what it's about so we want some +kind of an inverse statement for + + align:start position:0% +kind of an inverse statement for + + + align:start position:0% +kind of an inverse statement for +quadratic uniformity more + + align:start position:0% + + + + align:start position:0% + +so recall back to our discussion of + + align:start position:0% +so recall back to our discussion of + + + align:start position:0% +so recall back to our discussion of +proof of Roth's theorem a Fourier + + align:start position:0% +proof of Roth's theorem a Fourier + + + align:start position:0% +proof of Roth's theorem a Fourier +analytic proof of roster we want to say + + align:start position:0% +analytic proof of roster we want to say + + + align:start position:0% +analytic proof of roster we want to say +that but now think about not three a ps4 + + align:start position:0% +that but now think about not three a ps4 + + + align:start position:0% +that but now think about not three a ps4 +four ATP's so we want to know if you + + align:start position:0% +four ATP's so we want to know if you + + + align:start position:0% +four ATP's so we want to know if you +have a function the pudding cube and + + align:start position:0% +have a function the pudding cube and + + + align:start position:0% +have a function the pudding cube and +this function is unbounded and I'm going + + align:start position:0% +this function is unbounded and I'm going + + + align:start position:0% +this function is unbounded and I'm going +to write down some notation which we are + + align:start position:0% +to write down some notation which we are + + + align:start position:0% +to write down some notation which we are +not going to define but the cowers u3 + + align:start position:0% +not going to define but the cowers u3 + + + align:start position:0% +not going to define but the cowers u3 +norm is at least some Delta so this is + + align:start position:0% +norm is at least some Delta so this is + + + align:start position:0% +norm is at least some Delta so this is +something which is related to for AP + + align:start position:0% +something which is related to for AP + + + align:start position:0% +something which is related to for AP +counts so in particular if this number + + align:start position:0% +counts so in particular if this number + + + align:start position:0% +counts so in particular if this number +is small then you have a counting number + + align:start position:0% +is small then you have a counting number + + + align:start position:0% +is small then you have a counting number +for for term arithmetic progressions + + align:start position:0% + + + + align:start position:0% + +if this is true then there exists a + + align:start position:0% +if this is true then there exists a + + + align:start position:0% +if this is true then there exists a +quadratic polynomial Q n variables over + + align:start position:0% +quadratic polynomial Q n variables over + + + align:start position:0% +quadratic polynomial Q n variables over +f2 such that your function f correlates + + align:start position:0% +f2 such that your function f correlates + + + align:start position:0% +f2 such that your function f correlates +with this quadratic exponential in Q and + + align:start position:0% +with this quadratic exponential in Q and + + + align:start position:0% +with this quadratic exponential in Q and +the correlation here is something where + + align:start position:0% +the correlation here is something where + + + align:start position:0% +the correlation here is something where +you have you only lose a polynomial in + + align:start position:0% +you have you only lose a polynomial in + + + align:start position:0% +you have you only lose a polynomial in +the parameters so previously I quoted + + align:start position:0% +the parameters so previously I quoted + + + align:start position:0% +the parameters so previously I quoted +something where you lose something + + align:start position:0% +something where you lose something + + + align:start position:0% +something where you lose something +that's only a constant in Delta and that + + align:start position:0% +that's only a constant in Delta and that + + + align:start position:0% +that's only a constant in Delta and that +is true that is no we believe so it's a + + align:start position:0% +is true that is no we believe so it's a + + + align:start position:0% +is true that is no we believe so it's a +conjecture that you only do so + + align:start position:0% +conjecture that you only do so + + + align:start position:0% +conjecture that you only do so +polynomial in these parameters so this + + align:start position:0% +polynomial in these parameters so this + + + align:start position:0% +polynomial in these parameters so this +type of statement remember now prove a + + align:start position:0% +type of statement remember now prove a + + + align:start position:0% +type of statement remember now prove a +roster something like this came up so + + align:start position:0% +roster something like this came up so + + + align:start position:0% +roster something like this came up so +something like this came up as a crucial + + align:start position:0% +something like this came up as a crucial + + + align:start position:0% +something like this came up as a crucial +step in the proof of roster if you have + + align:start position:0% +step in the proof of roster if you have + + + align:start position:0% +step in the proof of roster if you have +something where you look at counting + + align:start position:0% +something where you look at counting + + + align:start position:0% +something where you look at counting +lemma you exhibit something like this + + align:start position:0% +lemma you exhibit something like this + + + align:start position:0% +lemma you exhibit something like this +then you can exhibit a large Fourier + + align:start position:0% +then you can exhibit a large Fourier + + + align:start position:0% +then you can exhibit a large Fourier +character and in higher worded Fourier + + align:start position:0% +character and in higher worded Fourier + + + align:start position:0% +character and in higher worded Fourier +analysis something like this corresponds + + align:start position:0% +analysis something like this corresponds + + + align:start position:0% +analysis something like this corresponds +to a large four-year care having a large + + align:start position:0% +to a large four-year care having a large + + + align:start position:0% +to a large four-year care having a large +Fourier transform it turns out that all + + align:start position:0% +Fourier transform it turns out that all + + + align:start position:0% +Fourier transform it turns out that all +of these formulations of polynomial + + align:start position:0% +of these formulations of polynomial + + + align:start position:0% +of these formulations of polynomial +Fryman lucha conjectures are equivalent + + align:start position:0% +Fryman lucha conjectures are equivalent + + + align:start position:0% +Fryman lucha conjectures are equivalent +to each other and they're all equivalent + + align:start position:0% +to each other and they're all equivalent + + + align:start position:0% +to each other and they're all equivalent +in a very quantitative sense so upto + + align:start position:0% +in a very quantitative sense so upto + + + align:start position:0% +in a very quantitative sense so upto +polynomial changes depends so + + align:start position:0% +polynomial changes depends so + + + align:start position:0% +polynomial changes depends so +particularly if you can prove some + + align:start position:0% +particularly if you can prove some + + + align:start position:0% +particularly if you can prove some +bounds for some version then that + + align:start position:0% +bounds for some version then that + + + align:start position:0% +bounds for some version then that +automatically leads to balance for the + + align:start position:0% +automatically leads to balance for the + + + align:start position:0% +automatically leads to balance for the +other versions it was proof of + + align:start position:0% +other versions it was proof of + + + align:start position:0% +other versions it was proof of +equivalence is just not trivial but it's + + align:start position:0% +equivalence is just not trivial but it's + + + align:start position:0% +equivalence is just not trivial but it's +also it's not too complicated take some + + align:start position:0% +also it's not too complicated take some + + + align:start position:0% +also it's not too complicated take some +work but it's not too complicated the + + align:start position:0% +work but it's not too complicated the + + + align:start position:0% +work but it's not too complicated the +best bounds for the polynomial Fryman + + align:start position:0% +best bounds for the polynomial Fryman + + + align:start position:0% +best bounds for the polynomial Fryman +ruzic + + align:start position:0% +ruzic + + + align:start position:0% +ruzic +injector and thanks for all of these + + align:start position:0% +injector and thanks for all of these + + + align:start position:0% +injector and thanks for all of these +versions is again due to Tom Sanders and + + align:start position:0% +versions is again due to Tom Sanders and + + + align:start position:0% +versions is again due to Tom Sanders and +he proved a version of PFR with + + align:start position:0% +he proved a version of PFR with + + + align:start position:0% +he proved a version of PFR with +quasi-polynomial balanced with high + + align:start position:0% +quasi-polynomial balanced with high + + + align:start position:0% +quasi-polynomial balanced with high +quality polynomial bounds I mean for + + align:start position:0% +quality polynomial bounds I mean for + + + align:start position:0% +quality polynomial bounds I mean for +instance over here instead of K he + + align:start position:0% +instance over here instead of K he + + + align:start position:0% +instance over here instead of K he +proved it for something which is like e + + align:start position:0% +proved it for something which is like e + + + align:start position:0% +proved it for something which is like e +to the poly log K so like K to the log K + + align:start position:0% +to the poly log K so like K to the log K + + + align:start position:0% +to the poly log K so like K to the log K +but K to the poly knocking so it's + + align:start position:0% +but K to the poly knocking so it's + + + align:start position:0% +but K to the poly knocking so it's +almost polynomial but not quite there + + align:start position:0% +almost polynomial but not quite there + + + align:start position:0% +almost polynomial but not quite there +and it's considered a central open + + align:start position:0% +and it's considered a central open + + + align:start position:0% +and it's considered a central open +problem to better understand the + + align:start position:0% +problem to better understand the + + + align:start position:0% +problem to better understand the +polynomial Fryman Ruza conjecture and we + + align:start position:0% +polynomial Fryman Ruza conjecture and we + + + align:start position:0% +polynomial Fryman Ruza conjecture and we +believe that this is something that + + align:start position:0% +believe that this is something that + + + align:start position:0% +believe that this is something that +could be to a lot of important new tools + + align:start position:0% +could be to a lot of important new tools + + + align:start position:0% +could be to a lot of important new tools +and techniques that are relevant to the + + align:start position:0% +and techniques that are relevant to the + + + align:start position:0% +and techniques that are relevant to the +rest of additive combinatorics + + align:start position:0% + + + + align:start position:0% + +okay so question is so we know that that + + align:start position:0% +okay so question is so we know that that + + + align:start position:0% +okay so question is so we know that that +up there has 2 to the K okay so you're + + align:start position:0% +up there has 2 to the K okay so you're + + + align:start position:0% +up there has 2 to the K okay so you're +asking can you use this 2 to the K to + + align:start position:0% +asking can you use this 2 to the K to + + + align:start position:0% +asking can you use this 2 to the K to +get some bound for polynomial before for + + align:start position:0% +get some bound for polynomial before for + + + align:start position:0% +get some bound for polynomial before for +something like this and and the answer + + align:start position:0% +something like this and and the answer + + + align:start position:0% +something like this and and the answer +is yes so you can use that proof to go + + align:start position:0% +is yes so you can use that proof to go + + + align:start position:0% +is yes so you can use that proof to go +through some proofs and get here I don't + + align:start position:0% +through some proofs and get here I don't + + + align:start position:0% +through some proofs and get here I don't +remember how this equivalence goes but + + align:start position:0% +remember how this equivalence goes but + + + align:start position:0% +remember how this equivalence goes but +now remember that the proof of Freeman's + + align:start position:0% +now remember that the proof of Freeman's + + + align:start position:0% +now remember that the proof of Freeman's +theorem for f2 to the N wasn't so hard + + align:start position:0% +theorem for f2 to the N wasn't so hard + + + align:start position:0% +theorem for f2 to the N wasn't so hard +right so we didn't use very many tools + + align:start position:0% +right so we didn't use very many tools + + + align:start position:0% +right so we didn't use very many tools +unfortunately I don't have time to tell + + align:start position:0% +unfortunately I don't have time to tell + + + align:start position:0% +unfortunately I don't have time to tell +you the formulations of polynomial + + align:start position:0% +you the formulations of polynomial + + + align:start position:0% +you the formulations of polynomial +Fryman which a congestion over the + + align:start position:0% +Fryman which a congestion over the + + + align:start position:0% +Fryman which a congestion over the +integers and also over are billion + + align:start position:0% +integers and also over are billion + + + align:start position:0% +integers and also over are billion +arbitrary abelian groups but there are + + align:start position:0% +arbitrary abelian groups but there are + + + align:start position:0% +arbitrary abelian groups but there are +formulations over the integers and and + + align:start position:0% +formulations over the integers and and + + + align:start position:0% +formulations over the integers and and +that's one that people care just as much + + align:start position:0% +that's one that people care just as much + + + align:start position:0% +that's one that people care just as much +about and and there are also different + + align:start position:0% +about and and there are also different + + + align:start position:0% +about and and there are also different +equivalent versions but things are a bit + + align:start position:0% +equivalent versions but things are a bit + + + align:start position:0% +equivalent versions but things are a bit +nicer in the boolean case I'm sorry can + + align:start position:0% +nicer in the boolean case I'm sorry can + + + align:start position:0% +nicer in the boolean case I'm sorry can +you repeat the question + + align:start position:0% + + + + align:start position:0% + +well this is me ah so this is what's + + align:start position:0% +well this is me ah so this is what's + + + align:start position:0% +well this is me ah so this is what's +called a coward uniformity norm okay so + + align:start position:0% + + + + align:start position:0% + +something I encourage the male cop in + + align:start position:0% +something I encourage the male cop in + + + align:start position:0% +something I encourage the male cop in +fact there's an unassigned problem in + + align:start position:0% +fact there's an unassigned problem in + + + align:start position:0% +fact there's an unassigned problem in +problem set that's related to the couch + + align:start position:0% +problem set that's related to the couch + + + align:start position:0% +problem set that's related to the couch +uniformity no one before you - which is + + align:start position:0% +uniformity no one before you - which is + + + align:start position:0% +uniformity no one before you - which is +related for analysis but you three years + + align:start position:0% +related for analysis but you three years + + + align:start position:0% +related for analysis but you three years +we did it - for EPS and quadratic for + + align:start position:0% +we did it - for EPS and quadratic for + + + align:start position:0% +we did it - for EPS and quadratic for +urinalysis \ No newline at end of file diff --git a/IggngxY3riU.txt b/IggngxY3riU.txt new file mode 100644 index 0000000000000000000000000000000000000000..1ace6fe7dd8d6cab3ab021fa06a984ceebd8c52c --- /dev/null +++ b/IggngxY3riU.txt @@ -0,0 +1,483 @@ +align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +hi I'm Jessica and today I'm going to be + + align:start position:0% +hi I'm Jessica and today I'm going to be + + + align:start position:0% +hi I'm Jessica and today I'm going to be +talking about a chemical demonstration + + align:start position:0% +talking about a chemical demonstration + + + align:start position:0% +talking about a chemical demonstration +called the Briggs rasher + + align:start position:0% +called the Briggs rasher + + + align:start position:0% +called the Briggs rasher +reaction this reaction was discovered by + + align:start position:0% +reaction this reaction was discovered by + + + align:start position:0% +reaction this reaction was discovered by +two San Francisco area high school + + align:start position:0% +two San Francisco area high school + + + align:start position:0% +two San Francisco area high school +chemistry teachers Briggs and rasher who + + align:start position:0% +chemistry teachers Briggs and rasher who + + + align:start position:0% +chemistry teachers Briggs and rasher who +were working in a lab to come up with a + + align:start position:0% +were working in a lab to come up with a + + + align:start position:0% +were working in a lab to come up with a +visually striking way to demonstrate an + + align:start position:0% +visually striking way to demonstrate an + + + align:start position:0% +visually striking way to demonstrate an +oscillating clock reaction + + align:start position:0% +oscillating clock reaction + + + align:start position:0% +oscillating clock reaction +let's watch mit's Dr John Dolan show us + + align:start position:0% +let's watch mit's Dr John Dolan show us + + + align:start position:0% +let's watch mit's Dr John Dolan show us +the reaction here he is at the Cambridge + + align:start position:0% +the reaction here he is at the Cambridge + + + align:start position:0% +the reaction here he is at the Cambridge +Science Festival okay so what I'm going + + align:start position:0% +Science Festival okay so what I'm going + + + align:start position:0% +Science Festival okay so what I'm going +to do is I'm going to pour three + + align:start position:0% +to do is I'm going to pour three + + + align:start position:0% +to do is I'm going to pour three +colorless Solutions into this + + align:start position:0% +colorless Solutions into this + + + align:start position:0% +colorless Solutions into this +speaker solution number one and I'm + + align:start position:0% +speaker solution number one and I'm + + + align:start position:0% +speaker solution number one and I'm +going to use kitchen chemistry so I'm + + align:start position:0% +going to use kitchen chemistry so I'm + + + align:start position:0% +going to use kitchen chemistry so I'm +using my eye here let me just see okay + + align:start position:0% +using my eye here let me just see okay + + + align:start position:0% +using my eye here let me just see okay +there we are + + align:start position:0% + + + + align:start position:0% + +second + + align:start position:0% + + + + align:start position:0% + +solution and the third solution + + align:start position:0% + + + + align:start position:0% + +so what happened Dr Dolan mixed three + + align:start position:0% +so what happened Dr Dolan mixed three + + + align:start position:0% +so what happened Dr Dolan mixed three +clear colorless Solutions together the + + align:start position:0% +clear colorless Solutions together the + + + align:start position:0% +clear colorless Solutions together the +first solution contains potassium iodate + + align:start position:0% +first solution contains potassium iodate + + + align:start position:0% +first solution contains potassium iodate +and sulfuric acid dissolved in water + + align:start position:0% + + + + align:start position:0% + +the second solution is malonic acid and + + align:start position:0% +the second solution is malonic acid and + + + align:start position:0% +the second solution is malonic acid and +manganese sulfate monohydrate in + + align:start position:0% + + + + align:start position:0% + +water and the third is hydrogen peroxide + + align:start position:0% +water and the third is hydrogen peroxide + + + align:start position:0% +water and the third is hydrogen peroxide +in water and when mixed together things + + align:start position:0% +in water and when mixed together things + + + align:start position:0% +in water and when mixed together things +get complicated the overall reaction is + + align:start position:0% + + + + align:start position:0% + +this so iodate hydrogen peroxide malonic + + align:start position:0% +this so iodate hydrogen peroxide malonic + + + align:start position:0% +this so iodate hydrogen peroxide malonic +acid in the presence of sulfuric acid + + align:start position:0% +acid in the presence of sulfuric acid + + + align:start position:0% +acid in the presence of sulfuric acid +reacts to produce this compound oxygen + + align:start position:0% +reacts to produce this compound oxygen + + + align:start position:0% +reacts to produce this compound oxygen +and + + align:start position:0% +and + + + align:start position:0% +and +water but think about the reaction this + + align:start position:0% +water but think about the reaction this + + + align:start position:0% +water but think about the reaction this +way it's equivalent to saying that metal + + align:start position:0% +way it's equivalent to saying that metal + + + align:start position:0% +way it's equivalent to saying that metal +and plastic react to produce a bicycle + + align:start position:0% +and plastic react to produce a bicycle + + + align:start position:0% +and plastic react to produce a bicycle +in reality there are many steps that + + align:start position:0% +in reality there are many steps that + + + align:start position:0% +in reality there are many steps that +occur between those raw materials and + + align:start position:0% +occur between those raw materials and + + + align:start position:0% +occur between those raw materials and +the finished result and the Brigs rasher + + align:start position:0% +the finished result and the Brigs rasher + + + align:start position:0% +the finished result and the Brigs rasher +reaction is similar here are the many + + align:start position:0% +reaction is similar here are the many + + + align:start position:0% +reaction is similar here are the many +subreactions that occur to get from the + + align:start position:0% +subreactions that occur to get from the + + + align:start position:0% +subreactions that occur to get from the +reactants to the products what we see is + + align:start position:0% +reactants to the products what we see is + + + align:start position:0% +reactants to the products what we see is +a cycle from colorless to + + align:start position:0% +a cycle from colorless to + + + align:start position:0% +a cycle from colorless to +Amber to dark + + align:start position:0% + + + + align:start position:0% + +blue and as these reactions run the + + align:start position:0% +blue and as these reactions run the + + + align:start position:0% +blue and as these reactions run the +relative amounts of the reactants and + + align:start position:0% +relative amounts of the reactants and + + + align:start position:0% +relative amounts of the reactants and +the products dictate the color of the + + align:start position:0% +the products dictate the color of the + + + align:start position:0% +the products dictate the color of the +solution I2 is + + align:start position:0% + + + + align:start position:0% + +Amber I minus is + + align:start position:0% +Amber I minus is + + + align:start position:0% +Amber I minus is +colorless and I3 minus is Deep Blue when + + align:start position:0% +colorless and I3 minus is Deep Blue when + + + align:start position:0% +colorless and I3 minus is Deep Blue when +it interacts with starch in the + + align:start position:0% +it interacts with starch in the + + + align:start position:0% +it interacts with starch in the +solution triiodide is formed when iodine + + align:start position:0% +solution triiodide is formed when iodine + + + align:start position:0% +solution triiodide is formed when iodine +and IOD died + + align:start position:0% +and IOD died + + + align:start position:0% +and IOD died +interact and this cycle continues until + + align:start position:0% +interact and this cycle continues until + + + align:start position:0% +interact and this cycle continues until +all the reactants are used up hope you + + align:start position:0% +all the reactants are used up hope you + + + align:start position:0% +all the reactants are used up hope you +enjoyed the video and I'll see you next + + align:start position:0% +enjoyed the video and I'll see you next + + + align:start position:0% +enjoyed the video and I'll see you next +time + + align:start position:0% +time + + + align:start position:0% +time +[Music] + + align:start position:0% + + + + align:start position:0% + +n + + align:start position:0% +n + + + align:start position:0% +n +[Music] \ No newline at end of file diff --git a/IrRgAWI6bmw.txt b/IrRgAWI6bmw.txt new file mode 100644 index 0000000000000000000000000000000000000000..3bc8b14143b46b8e0e05be47d8301f511e6049e6 --- /dev/null +++ b/IrRgAWI6bmw.txt @@ -0,0 +1,1707 @@ +align:start position:0% + +hi everyone so today I'd like to take a + + align:start position:0% +hi everyone so today I'd like to take a + + + align:start position:0% +hi everyone so today I'd like to take a +look at linear equations linear first + + align:start position:0% +look at linear equations linear first + + + align:start position:0% +look at linear equations linear first +order differential equations and + + align:start position:0% +order differential equations and + + + align:start position:0% +order differential equations and +specifically we're going to look at just + + align:start position:0% +specifically we're going to look at just + + + align:start position:0% +specifically we're going to look at just +exactly what is a linear equation so for + + align:start position:0% +exactly what is a linear equation so for + + + align:start position:0% +exactly what is a linear equation so for +example which of these equations are + + align:start position:0% +example which of these equations are + + + align:start position:0% +example which of these equations are +linear and then second of all we're + + align:start position:0% +linear and then second of all we're + + + align:start position:0% +linear and then second of all we're +going to take a look at + + align:start position:0% +going to take a look at + + + align:start position:0% +going to take a look at +superposition and I uh we ask to + + align:start position:0% +superposition and I uh we ask to + + + align:start position:0% +superposition and I uh we ask to +consider the differential equation Y dot + + align:start position:0% +consider the differential equation Y dot + + + align:start position:0% +consider the differential equation Y dot ++ y^2 = some function Q of T and just to + + align:start position:0% ++ y^2 = some function Q of T and just to + + + align:start position:0% ++ y^2 = some function Q of T and just to +demonstrate that this equation does not + + align:start position:0% +demonstrate that this equation does not + + + align:start position:0% +demonstrate that this equation does not +satisfy the superposition principle so + + align:start position:0% +satisfy the superposition principle so + + + align:start position:0% +satisfy the superposition principle so +I'll let you take a look at this problem + + align:start position:0% +I'll let you take a look at this problem + + + align:start position:0% +I'll let you take a look at this problem +and try and work it out for yourself and + + align:start position:0% +and try and work it out for yourself and + + + align:start position:0% +and try and work it out for yourself and +I'll be back in a + + align:start position:0% + + + + align:start position:0% + +minute hi everyone welcome back all + + align:start position:0% +minute hi everyone welcome back all + + + align:start position:0% +minute hi everyone welcome back all +right so we're asked to figure out which + + align:start position:0% +right so we're asked to figure out which + + + align:start position:0% +right so we're asked to figure out which +of these equations are linear so just a + + align:start position:0% + + + + align:start position:0% + +recap what does it mean for an equation + + align:start position:0% +recap what does it mean for an equation + + + align:start position:0% +recap what does it mean for an equation +to be linear what does it mean for a + + align:start position:0% +to be linear what does it mean for a + + + align:start position:0% +to be linear what does it mean for a +first order equation to be + + align:start position:0% +first order equation to be + + + align:start position:0% +first order equation to be +linear well it means that we can write + + align:start position:0% +linear well it means that we can write + + + align:start position:0% +linear well it means that we can write +it in the general + + align:start position:0% +it in the general + + + align:start position:0% +it in the general +form so if it if it's a function of X + + align:start position:0% + + + + align:start position:0% + +dydx plus some general function of X and + + align:start position:0% +dydx plus some general function of X and + + + align:start position:0% +dydx plus some general function of X and +this could be + + align:start position:0% +this could be + + + align:start position:0% +this could be +anything but the point is that it's + + align:start position:0% +anything but the point is that it's + + + align:start position:0% +anything but the point is that it's +multiplied just by y + + align:start position:0% + + + + align:start position:0% + +and then it can equal some arbitrary + + align:start position:0% +and then it can equal some arbitrary + + + align:start position:0% +and then it can equal some arbitrary +function Q ofx on the right hand side so + + align:start position:0% +function Q ofx on the right hand side so + + + align:start position:0% +function Q ofx on the right hand side so +every first order linear equation can be + + align:start position:0% +every first order linear equation can be + + + align:start position:0% +every first order linear equation can be +Rewritten in this + + align:start position:0% + + + + align:start position:0% + +form so let's tackle part A all right y + + align:start position:0% +form so let's tackle part A all right y + + + align:start position:0% +form so let's tackle part A all right y +dot plus KY equals Zer or Y dot equals + + align:start position:0% +dot plus KY equals Zer or Y dot equals + + + align:start position:0% +dot plus KY equals Zer or Y dot equals +KY we can just rewrite it + + align:start position:0% +KY we can just rewrite it + + + align:start position:0% +KY we can just rewrite it +as y do equals negative + + align:start position:0% +as y do equals negative + + + align:start position:0% +as y do equals negative +KY note that just some constant k is a + + align:start position:0% +KY note that just some constant k is a + + + align:start position:0% +KY note that just some constant k is a +function of time it's a constant + + align:start position:0% +function of time it's a constant + + + align:start position:0% +function of time it's a constant +function of time but it can just be + + align:start position:0% +function of time but it can just be + + + align:start position:0% +function of time but it can just be +thought of as a function of Time same + + align:start position:0% +thought of as a function of Time same + + + align:start position:0% +thought of as a function of Time same +with the right hand side it's zero and + + align:start position:0% +with the right hand side it's zero and + + + align:start position:0% +with the right hand side it's zero and +so this equation has the same form as + + align:start position:0% +so this equation has the same form as + + + align:start position:0% +so this equation has the same form as +our general uh first order linear + + align:start position:0% +our general uh first order linear + + + align:start position:0% +our general uh first order linear +equation so this is a linear + + align:start position:0% +equation so this is a linear + + + align:start position:0% +equation so this is a linear +equation let's take a look at question + + align:start position:0% +equation let's take a look at question + + + align:start position:0% +equation let's take a look at question +two part two we have y + + align:start position:0% +two part two we have y + + + align:start position:0% +two part two we have y +dot + y^2 T I'll bring the Y to the + + align:start position:0% +dot + y^2 T I'll bring the Y to the + + + align:start position:0% +dot + y^2 T I'll bring the Y to the +right or the left hand + + align:start position:0% +right or the left hand + + + align:start position:0% +right or the left hand +side if we do that we get this + + align:start position:0% +side if we do that we get this + + + align:start position:0% +side if we do that we get this +and just by comparing this to our + + align:start position:0% +and just by comparing this to our + + + align:start position:0% +and just by comparing this to our +generic first order linear OD we note + + align:start position:0% +generic first order linear OD we note + + + align:start position:0% +generic first order linear OD we note +that it's not of this form so + + align:start position:0% +that it's not of this form so + + + align:start position:0% +that it's not of this form so +specifically this is the term this is + + align:start position:0% +specifically this is the term this is + + + align:start position:0% +specifically this is the term this is +the bad term in question you see that + + align:start position:0% +the bad term in question you see that + + + align:start position:0% +the bad term in question you see that +it's y^2 * + + align:start position:0% +it's y^2 * + + + align:start position:0% +it's y^2 * +T notice how we can't we're not allowed + + align:start position:0% +T notice how we can't we're not allowed + + + align:start position:0% +T notice how we can't we're not allowed +to have any term that's y^ + + align:start position:0% +to have any term that's y^ + + + align:start position:0% +to have any term that's y^ +s uh in our first order linear equation + + align:start position:0% +s uh in our first order linear equation + + + align:start position:0% +s uh in our first order linear equation +now I will say this just as an + + align:start position:0% + + + + align:start position:0% + +aside this equation is also known as a + + align:start position:0% +aside this equation is also known as a + + + align:start position:0% +aside this equation is also known as a +beri equation and as an aside if you + + align:start position:0% +beri equation and as an aside if you + + + align:start position:0% +beri equation and as an aside if you +were to make a substitution u = 1 / + + align:start position:0% +were to make a substitution u = 1 / + + + align:start position:0% +were to make a substitution u = 1 / +Y and rewrote this equation in terms of + + align:start position:0% +Y and rewrote this equation in terms of + + + align:start position:0% +Y and rewrote this equation in terms of +U as the independent variable you'd find + + align:start position:0% +U as the independent variable you'd find + + + align:start position:0% +U as the independent variable you'd find +out that this equation would be linear + + align:start position:0% +out that this equation would be linear + + + align:start position:0% +out that this equation would be linear +in terms of U but as it's written now in + + align:start position:0% +in terms of U but as it's written now in + + + align:start position:0% +in terms of U but as it's written now in +terms of Y it's not + + align:start position:0% +terms of Y it's not + + + align:start position:0% +terms of Y it's not +linear so this is kind of an interesting + + align:start position:0% +linear so this is kind of an interesting + + + align:start position:0% +linear so this is kind of an interesting +point that sometimes we can get lucky + + align:start position:0% +point that sometimes we can get lucky + + + align:start position:0% +point that sometimes we can get lucky +and do a nonlinear transformation and + + align:start position:0% +and do a nonlinear transformation and + + + align:start position:0% +and do a nonlinear transformation and +convert a nonlinear equation into a + + align:start position:0% +convert a nonlinear equation into a + + + align:start position:0% +convert a nonlinear equation into a +linear one + + align:start position:0% + + + + align:start position:0% + +okay so for part three we + + align:start position:0% + + + + align:start position:0% + +have y prime plus cosx + + align:start position:0% + + + + align:start position:0% + +Y equals X + + align:start position:0% +Y equals X + + + align:start position:0% +Y equals X +cubed so again we see that this is a + + align:start position:0% +cubed so again we see that this is a + + + align:start position:0% +cubed so again we see that this is a +linear equation because we can + + align:start position:0% +linear equation because we can + + + align:start position:0% +linear equation because we can +identify P of X with cosine + + align:start position:0% + + + + align:start position:0% + +x q of X with x + + align:start position:0% +x q of X with x + + + align:start position:0% +x q of X with x +cubed so this equation has the general + + align:start position:0% +cubed so this equation has the general + + + align:start position:0% +cubed so this equation has the general +form of a linear + + align:start position:0% + + + + align:start position:0% + +OD for part + + align:start position:0% +OD for part + + + align:start position:0% +OD for part +four well if we take a look at it right + + align:start position:0% +four well if we take a look at it right + + + align:start position:0% +four well if we take a look at it right +away y dot ided Y is equal to T + + align:start position:0% +away y dot ided Y is equal to T + + + align:start position:0% +away y dot ided Y is equal to T +^2 it doesn't appear to be linear but of + + align:start position:0% +^2 it doesn't appear to be linear but of + + + align:start position:0% +^2 it doesn't appear to be linear but of +course we can multiply through by Y and + + align:start position:0% +course we can multiply through by Y and + + + align:start position:0% +course we can multiply through by Y and +rewrite + + align:start position:0% +rewrite + + + align:start position:0% +rewrite +things and of course this equation is + + align:start position:0% +things and of course this equation is + + + align:start position:0% +things and of course this equation is +equivalent to y dotus t^2 y y equal + + align:start position:0% +equivalent to y dotus t^2 y y equal + + + align:start position:0% +equivalent to y dotus t^2 y y equal +0 uh which again is linear + + align:start position:0% +0 uh which again is linear + + + align:start position:0% +0 uh which again is linear +because P of + + align:start position:0% +because P of + + + align:start position:0% +because P of +T can be identified with - t ^2 and Q of + + align:start position:0% +T can be identified with - t ^2 and Q of + + + align:start position:0% +T can be identified with - t ^2 and Q of +T can be identified with + + align:start position:0% +T can be identified with + + + align:start position:0% +T can be identified with +zero and then + + align:start position:0% + + + + align:start position:0% + +lastly for part five we + + align:start position:0% +lastly for part five we + + + align:start position:0% +lastly for part five we +have x^2 y y + + align:start position:0% +have x^2 y y + + + align:start position:0% +have x^2 y y +Prime + 4x + + align:start position:0% + + + + align:start position:0% + +equals X + + align:start position:0% +equals X + + + align:start position:0% +equals X +cubed and again if we were to try to + + align:start position:0% +cubed and again if we were to try to + + + align:start position:0% +cubed and again if we were to try to +write it in the general form of a linear + + align:start position:0% +write it in the general form of a linear + + + align:start position:0% +write it in the general form of a linear +OD which we have + + align:start position:0% + + + + align:start position:0% + +here it would look + + align:start position:0% + + + + align:start position:0% + +like 4X / x^2 + + align:start position:0% +like 4X / x^2 + + + align:start position:0% +like 4X / x^2 +y minus X Cub / x^2 + + align:start position:0% +y minus X Cub / x^2 + + + align:start position:0% +y minus X Cub / x^2 +y equals z and because there's a y on + + align:start position:0% +y equals z and because there's a y on + + + align:start position:0% +y equals z and because there's a y on +the denominator here this equation + + align:start position:0% +the denominator here this equation + + + align:start position:0% +the denominator here this equation +doesn't have the general form of a first + + align:start position:0% +doesn't have the general form of a first + + + align:start position:0% +doesn't have the general form of a first +order linear + + align:start position:0% +order linear + + + align:start position:0% +order linear +equation now again uh I I note that if + + align:start position:0% +equation now again uh I I note that if + + + align:start position:0% +equation now again uh I I note that if +you were to make a + + align:start position:0% +you were to make a + + + align:start position:0% +you were to make a +substitution U equal + + align:start position:0% +substitution U equal + + + align:start position:0% +substitution U equal +y^2 that substitution would make this + + align:start position:0% +y^2 that substitution would make this + + + align:start position:0% +y^2 that substitution would make this +equation + + align:start position:0% + + + + align:start position:0% + +linear okay so this concludes part a + + align:start position:0% + + + + align:start position:0% + +so for Part B we're given a differential + + align:start position:0% +so for Part B we're given a differential + + + align:start position:0% +so for Part B we're given a differential +equation Y + + align:start position:0% +equation Y + + + align:start position:0% +equation Y +dot plus + + align:start position:0% +dot plus + + + align:start position:0% +dot plus +y^2 is equal to Q of + + align:start position:0% +y^2 is equal to Q of + + + align:start position:0% +y^2 is equal to Q of +T and we want to show that this uh this + + align:start position:0% +T and we want to show that this uh this + + + align:start position:0% +T and we want to show that this uh this +equation doesn't satisfy the + + align:start position:0% +equation doesn't satisfy the + + + align:start position:0% +equation doesn't satisfy the +superposition + + align:start position:0% +superposition + + + align:start position:0% +superposition +principle now you might note that this + + align:start position:0% +principle now you might note that this + + + align:start position:0% +principle now you might note that this +equation is not + + align:start position:0% +equation is not + + + align:start position:0% +equation is not +linear so and uh second of all we know + + align:start position:0% +linear so and uh second of all we know + + + align:start position:0% +linear so and uh second of all we know +that linear equations satisfy the + + align:start position:0% +that linear equations satisfy the + + + align:start position:0% +that linear equations satisfy the +superposition + + align:start position:0% + + + + align:start position:0% + +principle so we're we need to exploit + + align:start position:0% +principle so we're we need to exploit + + + align:start position:0% +principle so we're we need to exploit +the fact that it's a nonlinear equation + + align:start position:0% +the fact that it's a nonlinear equation + + + align:start position:0% +the fact that it's a nonlinear equation +to make it fail uh the superposition + + align:start position:0% +to make it fail uh the superposition + + + align:start position:0% +to make it fail uh the superposition +principle and just as an example what we + + align:start position:0% +principle and just as an example what we + + + align:start position:0% +principle and just as an example what we +can do is I can just pick a couple right + + align:start position:0% +can do is I can just pick a couple right + + + align:start position:0% +can do is I can just pick a couple right +hand sides Q uh as examples of uh this + + align:start position:0% +hand sides Q uh as examples of uh this + + + align:start position:0% +hand sides Q uh as examples of uh this +OD so we can imagine we have a solution + + align:start position:0% +OD so we can imagine we have a solution + + + align:start position:0% +OD so we can imagine we have a solution +y1 which solves the + + align:start position:0% +y1 which solves the + + + align:start position:0% +y1 which solves the +OD y1 dot + + + align:start position:0% +OD y1 dot + + + + align:start position:0% +OD y1 dot + +y12 equals I'm just going to say one on + + align:start position:0% +y12 equals I'm just going to say one on + + + align:start position:0% +y12 equals I'm just going to say one on +the right hand side + + align:start position:0% +the right hand side + + + align:start position:0% +the right hand side +and I can also take another function + + align:start position:0% +and I can also take another function + + + align:start position:0% +and I can also take another function +Y2 which say satisfies this differential + + align:start position:0% +Y2 which say satisfies this differential + + + align:start position:0% +Y2 which say satisfies this differential +equation say t so all I've done is I've + + align:start position:0% +equation say t so all I've done is I've + + + align:start position:0% +equation say t so all I've done is I've +just picked one q1 on the right hand + + align:start position:0% +just picked one q1 on the right hand + + + align:start position:0% +just picked one q1 on the right hand +side and another function Q2 and I + + align:start position:0% +side and another function Q2 and I + + + align:start position:0% +side and another function Q2 and I +imagine that I have a solution y1 which + + align:start position:0% +imagine that I have a solution y1 which + + + align:start position:0% +imagine that I have a solution y1 which +satisfies this differential equation and + + align:start position:0% +satisfies this differential equation and + + + align:start position:0% +satisfies this differential equation and +Y2 which satisfies this differential + + align:start position:0% +Y2 which satisfies this differential + + + align:start position:0% +Y2 which satisfies this differential +equation so what does the superposition + + align:start position:0% +equation so what does the superposition + + + align:start position:0% +equation so what does the superposition +principle + + align:start position:0% +principle + + + align:start position:0% +principle +say well super + + align:start position:0% + + + + align:start position:0% + +position + + align:start position:0% +position + + + align:start position:0% +position +says that if y1 solves this equation and + + align:start position:0% +says that if y1 solves this equation and + + + align:start position:0% +says that if y1 solves this equation and +Y2 solves this equation then the + + align:start position:0% +Y2 solves this equation then the + + + align:start position:0% +Y2 solves this equation then the +function + + align:start position:0% +function + + + align:start position:0% +function +yal + + align:start position:0% +yal + + + align:start position:0% +yal +y1 + Y + + align:start position:0% +y1 + Y + + + align:start position:0% +y1 + Y +2 must solve the + + align:start position:0% + + + + align:start position:0% + +equation Y dot + y^ 2 equals the sum of + + align:start position:0% +equation Y dot + y^ 2 equals the sum of + + + align:start position:0% +equation Y dot + y^ 2 equals the sum of +the right hand side 1 plus + + align:start position:0% +the right hand side 1 plus + + + align:start position:0% +the right hand side 1 plus +T so if we try and substitute in y1 + Y2 + + align:start position:0% +T so if we try and substitute in y1 + Y2 + + + align:start position:0% +T so if we try and substitute in y1 + Y2 +into this equation we're going to come + + align:start position:0% +into this equation we're going to come + + + align:start position:0% +into this equation we're going to come +to a contradiction so let's do that now + + align:start position:0% +to a contradiction so let's do that now + + + align:start position:0% +to a contradiction so let's do that now +so we take d by + + align:start position:0% +so we take d by + + + align:start position:0% +so we take d by +DT of y1 + Y + + align:start position:0% +DT of y1 + Y + + + align:start position:0% +DT of y1 + Y +2 and I'm going to add it to y1 + Y 2 + + align:start position:0% +2 and I'm going to add it to y1 + Y 2 + + + align:start position:0% +2 and I'm going to add it to y1 + Y 2 +quantity + + align:start position:0% + + + + align:start position:0% + +squared + + align:start position:0% +squared + + + align:start position:0% +squared +okay and now what I can do is I can just + + align:start position:0% +okay and now what I can do is I can just + + + align:start position:0% +okay and now what I can do is I can just +simplify this so I get y1 dot plus Y2 + + align:start position:0% +simplify this so I get y1 dot plus Y2 + + + align:start position:0% +simplify this so I get y1 dot plus Y2 +Dot and I can expand out this + + align:start position:0% +Dot and I can expand out this + + + align:start position:0% +Dot and I can expand out this +Square so I get y1 2 + Y 2^ + + align:start position:0% +Square so I get y1 2 + Y 2^ + + + align:start position:0% +Square so I get y1 2 + Y 2^ +2 + 2 y1 y + + align:start position:0% +2 + 2 y1 y + + + align:start position:0% +2 + 2 y1 y +2 and now what I'm going to do is I'm + + align:start position:0% +2 and now what I'm going to do is I'm + + + align:start position:0% +2 and now what I'm going to do is I'm +going to combine the term + + align:start position:0% +going to combine the term + + + align:start position:0% +going to combine the term +y1 with + + align:start position:0% +y1 with + + + align:start position:0% +y1 with +y12 and by + + align:start position:0% +y12 and by + + + align:start position:0% +y12 and by +construction y1 do + y12 is equal to 1 + + align:start position:0% +construction y1 do + y12 is equal to 1 + + + align:start position:0% +construction y1 do + y12 is equal to 1 +because I assume that it s satisfied + + align:start position:0% +because I assume that it s satisfied + + + align:start position:0% +because I assume that it s satisfied +this differential + + align:start position:0% +this differential + + + align:start position:0% +this differential +equation and then in addition by + + align:start position:0% +equation and then in addition by + + + align:start position:0% +equation and then in addition by +construction Y2 dot + Y 2^ 2 + + align:start position:0% +construction Y2 dot + Y 2^ 2 + + + align:start position:0% +construction Y2 dot + Y 2^ 2 +satisfies uh the right hand side of the + + align:start position:0% +satisfies uh the right hand side of the + + + align:start position:0% +satisfies uh the right hand side of the +second equation with + + align:start position:0% + + + + align:start position:0% + +T so I get 1+ + + align:start position:0% +T so I get 1+ + + + align:start position:0% +T so I get 1+ +T but I'm left over with this other + + align:start position:0% +T but I'm left over with this other + + + align:start position:0% +T but I'm left over with this other +piece 2 y1 Y + + align:start position:0% +piece 2 y1 Y + + + align:start position:0% +piece 2 y1 Y +2 okay so in general if I take a + + align:start position:0% +2 okay so in general if I take a + + + align:start position:0% +2 okay so in general if I take a +function which solves this differential + + align:start position:0% +function which solves this differential + + + align:start position:0% +function which solves this differential +equation and another function which + + align:start position:0% +equation and another function which + + + align:start position:0% +equation and another function which +solves this differential equation and I + + align:start position:0% +solves this differential equation and I + + + align:start position:0% +solves this differential equation and I +add them together and plug it into the + + align:start position:0% +add them together and plug it into the + + + align:start position:0% +add them together and plug it into the +left hand side of this differential + + align:start position:0% +left hand side of this differential + + + align:start position:0% +left hand side of this differential +equation I get something which is 1+ t + + align:start position:0% +equation I get something which is 1+ t + + + align:start position:0% +equation I get something which is 1+ t +plus some other + + align:start position:0% +plus some other + + + align:start position:0% +plus some other +stuff and if it did satisfy the + + align:start position:0% +stuff and if it did satisfy the + + + align:start position:0% +stuff and if it did satisfy the +principle of + + align:start position:0% +principle of + + + align:start position:0% +principle of +superposition it must + + align:start position:0% +superposition it must + + + align:start position:0% +superposition it must +satisfy it must equal 1 plus + + align:start position:0% +satisfy it must equal 1 plus + + + align:start position:0% +satisfy it must equal 1 plus +T so we arrive at a contradiction + + align:start position:0% +T so we arrive at a contradiction + + + align:start position:0% +T so we arrive at a contradiction +because it doesn't equal 1+ T in fact it + + align:start position:0% +because it doesn't equal 1+ T in fact it + + + align:start position:0% +because it doesn't equal 1+ T in fact it +fails to equal 1 plus T by this term 2 + + align:start position:0% +fails to equal 1 plus T by this term 2 + + + align:start position:0% +fails to equal 1 plus T by this term 2 +y1 Y2 and this term comes directly from + + align:start position:0% +y1 Y2 and this term comes directly from + + + align:start position:0% +y1 Y2 and this term comes directly from +the fact that we had a nonlinearity in + + align:start position:0% +the fact that we had a nonlinearity in + + + align:start position:0% +the fact that we had a nonlinearity in +the + + align:start position:0% +the + + + align:start position:0% +the +equation so this is just one uh + + align:start position:0% +equation so this is just one uh + + + align:start position:0% +equation so this is just one uh +illustration of the fact that a + + align:start position:0% +illustration of the fact that a + + + align:start position:0% +illustration of the fact that a +nonlinear equation doesn't necessarily + + align:start position:0% +nonlinear equation doesn't necessarily + + + align:start position:0% +nonlinear equation doesn't necessarily +satisfy the super superposition + + align:start position:0% +satisfy the super superposition + + + align:start position:0% +satisfy the super superposition +principle whereas every linear equation + + align:start position:0% +principle whereas every linear equation + + + align:start position:0% +principle whereas every linear equation +satisfies a superposition principle this + + align:start position:0% +satisfies a superposition principle this + + + align:start position:0% +satisfies a superposition principle this +is is one reason we love linear + + align:start position:0% +is is one reason we love linear + + + align:start position:0% +is is one reason we love linear +equations and we study them + + align:start position:0% +equations and we study them + + + align:start position:0% +equations and we study them +extensively okay so uh I'd just like to + + align:start position:0% +extensively okay so uh I'd just like to + + + align:start position:0% +extensively okay so uh I'd just like to +conclude here and I'll uh see you next + + align:start position:0% +conclude here and I'll uh see you next + + + align:start position:0% +conclude here and I'll uh see you next +time \ No newline at end of file diff --git a/IwF_N2IDB48.txt b/IwF_N2IDB48.txt new file mode 100644 index 0000000000000000000000000000000000000000..0cfff68ab9c1904b2ef2ef8f064c5949b4bbe77c --- /dev/null +++ b/IwF_N2IDB48.txt @@ -0,0 +1,8235 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +to view additional materials from + + align:start position:0% +to view additional materials from + + + align:start position:0% +to view additional materials from +hundreds of MIT courses visit MIT open + + align:start position:0% +hundreds of MIT courses visit MIT open + + + align:start position:0% +hundreds of MIT courses visit MIT open +courseware at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu uh one announcement there'll + + align:start position:0% +ocw.mit.edu uh one announcement there'll + + + align:start position:0% +ocw.mit.edu uh one announcement there'll +be the uh uh quiz 9 weekly quiz tomorrow + + align:start position:0% +be the uh uh quiz 9 weekly quiz tomorrow + + + align:start position:0% +be the uh uh quiz 9 weekly quiz tomorrow +based on the content of homework 9 which + + align:start position:0% +based on the content of homework 9 which + + + align:start position:0% +based on the content of homework 9 which +is uh um + + align:start position:0% +is uh um + + + align:start position:0% +is uh um +I don't remember what it is but you know + + align:start position:0% +I don't remember what it is but you know + + + align:start position:0% +I don't remember what it is but you know +what it + + align:start position:0% +what it + + + align:start position:0% +what it +is I made it up it's I'm already + + align:start position:0% +is I made it up it's I'm already + + + align:start position:0% +is I made it up it's I'm already +thinking about the next the next + + align:start position:0% +thinking about the next the next + + + align:start position:0% +thinking about the next the next +glorious event + + align:start position:0% +glorious event + + + align:start position:0% +glorious event +so oh there's I now remember there's + + align:start position:0% +so oh there's I now remember there's + + + align:start position:0% +so oh there's I now remember there's +chemical + + align:start position:0% +chemical + + + align:start position:0% +chemical +kinetics and glasses that's right + + align:start position:0% +kinetics and glasses that's right + + + align:start position:0% +kinetics and glasses that's right +chemical kinetics and amorphous solids + + align:start position:0% +chemical kinetics and amorphous solids + + + align:start position:0% +chemical kinetics and amorphous solids +that's right good okay um last day we + + align:start position:0% +that's right good okay um last day we + + + align:start position:0% +that's right good okay um last day we +started talking about diffusion which is + + align:start position:0% +started talking about diffusion which is + + + align:start position:0% +started talking about diffusion which is +a solid state mass transport by random + + align:start position:0% +a solid state mass transport by random + + + align:start position:0% +a solid state mass transport by random +Aton I motion uh and we were drawn to + + align:start position:0% +Aton I motion uh and we were drawn to + + + align:start position:0% +Aton I motion uh and we were drawn to +the paper that's up on the display which + + align:start position:0% +the paper that's up on the display which + + + align:start position:0% +the paper that's up on the display which +was published in 1855 by uh Adolf Fick + + align:start position:0% +was published in 1855 by uh Adolf Fick + + + align:start position:0% +was published in 1855 by uh Adolf Fick +which uh gave us the uh law that bears + + align:start position:0% +which uh gave us the uh law that bears + + + align:start position:0% +which uh gave us the uh law that bears +his name uh describing how matter + + align:start position:0% +his name uh describing how matter + + + align:start position:0% +his name uh describing how matter +diffuses through matter uh but fi was uh + + align:start position:0% +diffuses through matter uh but fi was uh + + + align:start position:0% +diffuses through matter uh but fi was uh +a very talented individual and I want to + + align:start position:0% +a very talented individual and I want to + + + align:start position:0% +a very talented individual and I want to +draw attention to something else um in + + align:start position:0% +draw attention to something else um in + + + align:start position:0% +draw attention to something else um in +1870 he described the way of U remember + + align:start position:0% +1870 he described the way of U remember + + + align:start position:0% +1870 he described the way of U remember +he was a phys physiologist he actually + + align:start position:0% +he was a phys physiologist he actually + + + align:start position:0% +he was a phys physiologist he actually +did some work in medicine as well and uh + + align:start position:0% +did some work in medicine as well and uh + + + align:start position:0% +did some work in medicine as well and uh +he described what uh survives to this + + align:start position:0% +he described what uh survives to this + + + align:start position:0% +he described what uh survives to this +day as the Fick principle for + + align:start position:0% +day as the Fick principle for + + + align:start position:0% +day as the Fick principle for +determining uh cardiac output and + + align:start position:0% +determining uh cardiac output and + + + align:start position:0% +determining uh cardiac output and +basically equates the amount of uptake + + align:start position:0% +basically equates the amount of uptake + + + align:start position:0% +basically equates the amount of uptake +of oxygen by the lungs with the amount + + align:start position:0% +of oxygen by the lungs with the amount + + + align:start position:0% +of oxygen by the lungs with the amount +that should be distributed uh in the + + align:start position:0% +that should be distributed uh in the + + + align:start position:0% +that should be distributed uh in the +blood but you have to take arterial + + align:start position:0% +blood but you have to take arterial + + + align:start position:0% +blood but you have to take arterial +oxygen pressure minus uh venal oxygen + + align:start position:0% +oxygen pressure minus uh venal oxygen + + + align:start position:0% +oxygen pressure minus uh venal oxygen +pressure to get the efficiency of the + + align:start position:0% +pressure to get the efficiency of the + + + align:start position:0% +pressure to get the efficiency of the +heart and so uh found this little uh uh + + align:start position:0% +heart and so uh found this little uh uh + + + align:start position:0% +heart and so uh found this little uh uh +Cartoon off the web that just uh briefly + + align:start position:0% +Cartoon off the web that just uh briefly + + + align:start position:0% +Cartoon off the web that just uh briefly +uh encapsulates the notion of the FI + + align:start position:0% +uh encapsulates the notion of the FI + + + align:start position:0% +uh encapsulates the notion of the FI +principle for uh measuring a cardiac + + align:start position:0% +principle for uh measuring a cardiac + + + align:start position:0% +principle for uh measuring a cardiac +output his nephew by the way uh who was + + align:start position:0% +output his nephew by the way uh who was + + + align:start position:0% +output his nephew by the way uh who was +orphaned as a young child came also has + + align:start position:0% +orphaned as a young child came also has + + + align:start position:0% +orphaned as a young child came also has +the name Adolf Fick and the young Adolf + + align:start position:0% +the name Adolf Fick and the young Adolf + + + align:start position:0% +the name Adolf Fick and the young Adolf +Fick uh the nephew um was strongly + + align:start position:0% +Fick uh the nephew um was strongly + + + align:start position:0% +Fick uh the nephew um was strongly +influenced by um the uncle and he went + + align:start position:0% +influenced by um the uncle and he went + + + align:start position:0% +influenced by um the uncle and he went +on to invent uh the contact lens so this + + align:start position:0% +on to invent uh the contact lens so this + + + align:start position:0% +on to invent uh the contact lens so this +has been quite uh prolific in ways that + + align:start position:0% +has been quite uh prolific in ways that + + + align:start position:0% +has been quite uh prolific in ways that +influence many of us how many in this + + align:start position:0% +influence many of us how many in this + + + align:start position:0% +influence many of us how many in this +room are wearing contact + + align:start position:0% +room are wearing contact + + + align:start position:0% +room are wearing contact +lenses and uh I think we're all thankful + + align:start position:0% +lenses and uh I think we're all thankful + + + align:start position:0% +lenses and uh I think we're all thankful +that there is some cardiac efficiency so + + align:start position:0% +that there is some cardiac efficiency so + + + align:start position:0% +that there is some cardiac efficiency so +I think we're all + + align:start position:0% +I think we're all + + + align:start position:0% +I think we're all +beneficiaries okay so let's take a look + + align:start position:0% +beneficiaries okay so let's take a look + + + align:start position:0% +beneficiaries okay so let's take a look +uh in more detail at what Fick taught us + + align:start position:0% +uh in more detail at what Fick taught us + + + align:start position:0% +uh in more detail at what Fick taught us +he said that if we have Ingress of + + align:start position:0% +he said that if we have Ingress of + + + align:start position:0% +he said that if we have Ingress of +species ey into some solid um the rate + + align:start position:0% +species ey into some solid um the rate + + + align:start position:0% +species ey into some solid um the rate +of Ingress is given by the uh equation + + align:start position:0% +of Ingress is given by the uh equation + + + align:start position:0% +of Ingress is given by the uh equation +shown here which expresses the flux + + align:start position:0% +shown here which expresses the flux + + + align:start position:0% +shown here which expresses the flux +which is mass per unit time uh per unit + + align:start position:0% +which is mass per unit time uh per unit + + + align:start position:0% +which is mass per unit time uh per unit +cross-sectional area as proportional to + + align:start position:0% +cross-sectional area as proportional to + + + align:start position:0% +cross-sectional area as proportional to +the concentration gradient and the + + align:start position:0% +the concentration gradient and the + + + align:start position:0% +the concentration gradient and the +proportionality constant is the + + align:start position:0% +proportionality constant is the + + + align:start position:0% +proportionality constant is the +diffusion coefficient and what we see + + align:start position:0% +diffusion coefficient and what we see + + + align:start position:0% +diffusion coefficient and what we see +here is uh a uh a sketch of what that + + align:start position:0% +here is uh a uh a sketch of what that + + + align:start position:0% +here is uh a uh a sketch of what that +might look like uh some initial surface + + align:start position:0% +might look like uh some initial surface + + + align:start position:0% +might look like uh some initial surface +concentration uh held constant with + + align:start position:0% +concentration uh held constant with + + + align:start position:0% +concentration uh held constant with +Ingress of material and since the uh + + align:start position:0% +Ingress of material and since the uh + + + align:start position:0% +Ingress of material and since the uh +flux is the derivative you can see that + + align:start position:0% +flux is the derivative you can see that + + + align:start position:0% +flux is the derivative you can see that +the the flux but for some multiplication + + align:start position:0% +the the flux but for some multiplication + + + align:start position:0% +the the flux but for some multiplication +Factor tracks with the uh concentration + + align:start position:0% +Factor tracks with the uh concentration + + + align:start position:0% +Factor tracks with the uh concentration +we have the steepest concentration + + align:start position:0% +we have the steepest concentration + + + align:start position:0% +we have the steepest concentration +gradient at the surface and deep inside + + align:start position:0% +gradient at the surface and deep inside + + + align:start position:0% +gradient at the surface and deep inside +the specimen there is uh essentially no + + align:start position:0% +the specimen there is uh essentially no + + + align:start position:0% +the specimen there is uh essentially no +concentration gradient so the flux + + align:start position:0% +concentration gradient so the flux + + + align:start position:0% +concentration gradient so the flux +attenuates so flux shown here in fuchsia + + align:start position:0% +attenuates so flux shown here in fuchsia + + + align:start position:0% +attenuates so flux shown here in fuchsia +and concentration shown here and profile + + align:start position:0% +and concentration shown here and profile + + + align:start position:0% +and concentration shown here and profile +when I say + + align:start position:0% +when I say + + + align:start position:0% +when I say +profile profile means uh something as a + + align:start position:0% +profile profile means uh something as a + + + align:start position:0% +profile profile means uh something as a +function of of distance so profile in + + align:start position:0% +function of of distance so profile in + + + align:start position:0% +function of of distance so profile in +this case it's a concentration profile + + align:start position:0% +this case it's a concentration profile + + + align:start position:0% +this case it's a concentration profile +or a flux profile so you can see those + + align:start position:0% +or a flux profile so you can see those + + + align:start position:0% +or a flux profile so you can see those +two and then we started looking at uh + + align:start position:0% +two and then we started looking at uh + + + align:start position:0% +two and then we started looking at uh +some of the atomistics and we reason + + align:start position:0% +some of the atomistics and we reason + + + align:start position:0% +some of the atomistics and we reason +that there's some uh jumping involved + + align:start position:0% +that there's some uh jumping involved + + + align:start position:0% +that there's some uh jumping involved +and with the jumping comes the notion of + + align:start position:0% +and with the jumping comes the notion of + + + align:start position:0% +and with the jumping comes the notion of +activation yeah we looked at this and we + + align:start position:0% +activation yeah we looked at this and we + + + align:start position:0% +activation yeah we looked at this and we +concluded that there's an activation + + align:start position:0% +concluded that there's an activation + + + align:start position:0% +concluded that there's an activation +energy associated with jumping uh + + align:start position:0% +energy associated with jumping uh + + + align:start position:0% +energy associated with jumping uh +through that saddle point an arous type + + align:start position:0% +through that saddle point an arous type + + + align:start position:0% +through that saddle point an arous type +Behavior natural log of D linear in + + align:start position:0% +Behavior natural log of D linear in + + + align:start position:0% +Behavior natural log of D linear in +reciprocal of the absolute temperature + + align:start position:0% +reciprocal of the absolute temperature + + + align:start position:0% +reciprocal of the absolute temperature +remember this is not the ridberg + + align:start position:0% +remember this is not the ridberg + + + align:start position:0% +remember this is not the ridberg +constant this is the gas constant which + + align:start position:0% +constant this is the gas constant which + + + align:start position:0% +constant this is the gas constant which +is the product of the boltzman + + align:start position:0% +is the product of the boltzman + + + align:start position:0% +is the product of the boltzman +constant the boltzman constant and the + + align:start position:0% +constant the boltzman constant and the + + + align:start position:0% +constant the boltzman constant and the +avagadro number and units will give you + + align:start position:0% +avagadro number and units will give you + + + align:start position:0% +avagadro number and units will give you +a clue as to which to use if the uh + + align:start position:0% +a clue as to which to use if the uh + + + align:start position:0% +a clue as to which to use if the uh +activation energy is in units per mole + + align:start position:0% +activation energy is in units per mole + + + align:start position:0% +activation energy is in units per mole +then obviously use the gas constant + + align:start position:0% +then obviously use the gas constant + + + align:start position:0% +then obviously use the gas constant +otherwise you use the bolman constant + + align:start position:0% +otherwise you use the bolman constant + + + align:start position:0% +otherwise you use the bolman constant +and when we looked at the atomistics + + align:start position:0% +and when we looked at the atomistics + + + align:start position:0% +and when we looked at the atomistics +further we reasoned that when we have + + align:start position:0% +further we reasoned that when we have + + + align:start position:0% +further we reasoned that when we have +diffusion by vacancy jump mechanism this + + align:start position:0% +diffusion by vacancy jump mechanism this + + + align:start position:0% +diffusion by vacancy jump mechanism this +activation energy up here in the + + align:start position:0% +activation energy up here in the + + + align:start position:0% +activation energy up here in the +equation is the sum of two components + + align:start position:0% +equation is the sum of two components + + + align:start position:0% +equation is the sum of two components +one being the enthalpy of vacancy + + align:start position:0% +one being the enthalpy of vacancy + + + align:start position:0% +one being the enthalpy of vacancy +formation which is really the negative + + align:start position:0% +formation which is really the negative + + + align:start position:0% +formation which is really the negative +of the bonding energy and then the + + align:start position:0% +of the bonding energy and then the + + + align:start position:0% +of the bonding energy and then the +energy associated with the atom + + align:start position:0% +energy associated with the atom + + + align:start position:0% +energy associated with the atom +migration which is the energy of + + align:start position:0% +migration which is the energy of + + + align:start position:0% +migration which is the energy of +squeezing through that Saddle Point + + align:start position:0% +squeezing through that Saddle Point + + + align:start position:0% +squeezing through that Saddle Point +shown in the in the figure in the case + + align:start position:0% +shown in the in the figure in the case + + + align:start position:0% +shown in the in the figure in the case +of interstitial diffusion we don't have + + align:start position:0% +of interstitial diffusion we don't have + + + align:start position:0% +of interstitial diffusion we don't have +to uh form vacancies there's enough + + align:start position:0% +to uh form vacancies there's enough + + + align:start position:0% +to uh form vacancies there's enough +vacant sites by virtue of the fact that + + align:start position:0% +vacant sites by virtue of the fact that + + + align:start position:0% +vacant sites by virtue of the fact that +uh we've got so much free volume even in + + align:start position:0% +uh we've got so much free volume even in + + + align:start position:0% +uh we've got so much free volume even in +a close-packed solid so we're really + + align:start position:0% +a close-packed solid so we're really + + + align:start position:0% +a close-packed solid so we're really +just paying for the um uh enthalpy of + + align:start position:0% +just paying for the um uh enthalpy of + + + align:start position:0% +just paying for the um uh enthalpy of +migration and then lastly we looked at + + align:start position:0% +migration and then lastly we looked at + + + align:start position:0% +migration and then lastly we looked at +how these two are related to the degree + + align:start position:0% +how these two are related to the degree + + + align:start position:0% +how these two are related to the degree +of confinement in other words the atom + + align:start position:0% +of confinement in other words the atom + + + align:start position:0% +of confinement in other words the atom +is restricted by the the the ease with + + align:start position:0% +is restricted by the the the ease with + + + align:start position:0% +is restricted by the the the ease with +which it can run down its appropriate + + align:start position:0% +which it can run down its appropriate + + + align:start position:0% +which it can run down its appropriate +Raceway and and we re reason that going + + align:start position:0% +Raceway and and we re reason that going + + + align:start position:0% +Raceway and and we re reason that going +through the bulk lattice is the most uh + + align:start position:0% +through the bulk lattice is the most uh + + + align:start position:0% +through the bulk lattice is the most uh +tortuous path and has the highest + + align:start position:0% +tortuous path and has the highest + + + align:start position:0% +tortuous path and has the highest +activation energy lowest diffusion + + align:start position:0% +activation energy lowest diffusion + + + align:start position:0% +activation energy lowest diffusion +coefficient grain boundaries have atoms + + align:start position:0% +coefficient grain boundaries have atoms + + + align:start position:0% +coefficient grain boundaries have atoms +with fewer uh nearest neighbors the + + align:start position:0% +with fewer uh nearest neighbors the + + + align:start position:0% +with fewer uh nearest neighbors the +lower coordination num so the diffusion + + align:start position:0% +lower coordination num so the diffusion + + + align:start position:0% +lower coordination num so the diffusion +coefficient is higher in the grain + + align:start position:0% +coefficient is higher in the grain + + + align:start position:0% +coefficient is higher in the grain +boundary and it is highest along the + + align:start position:0% +boundary and it is highest along the + + + align:start position:0% +boundary and it is highest along the +free surface and we saw last day that + + align:start position:0% +free surface and we saw last day that + + + align:start position:0% +free surface and we saw last day that +the diffusion coefficient along the free + + align:start position:0% +the diffusion coefficient along the free + + + align:start position:0% +the diffusion coefficient along the free +surface of a solid approaches + + align:start position:0% +surface of a solid approaches + + + align:start position:0% +surface of a solid approaches +values equivalent to that of diffusion + + align:start position:0% +values equivalent to that of diffusion + + + align:start position:0% +values equivalent to that of diffusion +in a liquid state so what I want to do + + align:start position:0% +in a liquid state so what I want to do + + + align:start position:0% +in a liquid state so what I want to do +today is to step back to the Continuum + + align:start position:0% +today is to step back to the Continuum + + + align:start position:0% +today is to step back to the Continuum +and use fix law to uh describe what's + + align:start position:0% +and use fix law to uh describe what's + + + align:start position:0% +and use fix law to uh describe what's +going on mathematically uh in the macro + + align:start position:0% +going on mathematically uh in the macro + + + align:start position:0% +going on mathematically uh in the macro +world so I want to first start start + + align:start position:0% +world so I want to first start start + + + align:start position:0% +world so I want to first start start +with diffusion across a membrane so this + + align:start position:0% +with diffusion across a membrane so this + + + align:start position:0% +with diffusion across a membrane so this +is a membrane of some thickness + + align:start position:0% +is a membrane of some thickness + + + align:start position:0% +is a membrane of some thickness +um of some thickness L membrane of some + + align:start position:0% +um of some thickness L membrane of some + + + align:start position:0% +um of some thickness L membrane of some +thickness L and I'm going to put a gas + + align:start position:0% +thickness L and I'm going to put a gas + + + align:start position:0% +thickness L and I'm going to put a gas +uh to the left P1 and I'm going to hold + + align:start position:0% +uh to the left P1 and I'm going to hold + + + align:start position:0% +uh to the left P1 and I'm going to hold +it constant and to the right I'm going + + align:start position:0% +it constant and to the right I'm going + + + align:start position:0% +it constant and to the right I'm going +to have a gas at P2 also being held + + align:start position:0% +to have a gas at P2 also being held + + + align:start position:0% +to have a gas at P2 also being held +constant and just so that we're all on + + align:start position:0% +constant and just so that we're all on + + + align:start position:0% +constant and just so that we're all on +the same page I'm going to make P1 + + align:start position:0% +the same page I'm going to make P1 + + + align:start position:0% +the same page I'm going to make P1 +greater than P2 so that means that + + align:start position:0% +greater than P2 so that means that + + + align:start position:0% +greater than P2 so that means that +matter will diffuse from high pressure + + align:start position:0% +matter will diffuse from high pressure + + + align:start position:0% +matter will diffuse from high pressure +to low pressure high concentration to + + align:start position:0% +to low pressure high concentration to + + + align:start position:0% +to low pressure high concentration to +low concentration so that means the flux + + align:start position:0% +low concentration so that means the flux + + + align:start position:0% +low concentration so that means the flux +will be uh left to right and we can use + + align:start position:0% +will be uh left to right and we can use + + + align:start position:0% +will be uh left to right and we can use +the universal gas law pressure volume + + align:start position:0% +the universal gas law pressure volume + + + align:start position:0% +the universal gas law pressure volume +equals the product of mole number times + + align:start position:0% +equals the product of mole number times + + + align:start position:0% +equals the product of mole number times +gas constant times temperature in order + + align:start position:0% +gas constant times temperature in order + + + align:start position:0% +gas constant times temperature in order +to convert pressure units into + + align:start position:0% +to convert pressure units into + + + align:start position:0% +to convert pressure units into +concentration units we know that the + + align:start position:0% +concentration units we know that the + + + align:start position:0% +concentration units we know that the +concentration of a species I is simply + + align:start position:0% +concentration of a species I is simply + + + align:start position:0% +concentration of a species I is simply +equal to the mole number I divided by + + align:start position:0% +equal to the mole number I divided by + + + align:start position:0% +equal to the mole number I divided by +the total volume of the system right + + align:start position:0% +the total volume of the system right + + + align:start position:0% +the total volume of the system right +this is moles per unit volume so that's + + align:start position:0% +this is moles per unit volume so that's + + + align:start position:0% +this is moles per unit volume so that's +a concentration and so that means then + + align:start position:0% +a concentration and so that means then + + + align:start position:0% +a concentration and so that means then +that if we go to the universe of gas law + + align:start position:0% +that if we go to the universe of gas law + + + align:start position:0% +that if we go to the universe of gas law +that will give us p over RT so if we + + align:start position:0% +that will give us p over RT so if we + + + align:start position:0% +that will give us p over RT so if we +take a pressure divid it by the product + + align:start position:0% +take a pressure divid it by the product + + + align:start position:0% +take a pressure divid it by the product +of the gas constant temperature we'll + + align:start position:0% +of the gas constant temperature we'll + + + align:start position:0% +of the gas constant temperature we'll +move from pressure units to + + align:start position:0% +move from pressure units to + + + align:start position:0% +move from pressure units to +concentration units and so what I'd like + + align:start position:0% +concentration units and so what I'd like + + + align:start position:0% +concentration units and so what I'd like +to do is show what this this system + + align:start position:0% +to do is show what this this system + + + align:start position:0% +to do is show what this this system +looks like after some period of time so + + align:start position:0% +looks like after some period of time so + + + align:start position:0% +looks like after some period of time so +I'm going to put the convention with + + align:start position:0% +I'm going to put the convention with + + + align:start position:0% +I'm going to put the convention with +zero on the left surface so this is + + align:start position:0% +zero on the left surface so this is + + + align:start position:0% +zero on the left surface so this is +distance moving from left to right so + + align:start position:0% +distance moving from left to right so + + + align:start position:0% +distance moving from left to right so +xal 0 is the left surface of the + + align:start position:0% +xal 0 is the left surface of the + + + align:start position:0% +xal 0 is the left surface of the +membrane xals L is the right surface of + + align:start position:0% +membrane xals L is the right surface of + + + align:start position:0% +membrane xals L is the right surface of +the membrane and now let's put + + align:start position:0% +the membrane and now let's put + + + align:start position:0% +the membrane and now let's put +concentration C1 on the left surface and + + align:start position:0% +concentration C1 on the left surface and + + + align:start position:0% +concentration C1 on the left surface and +C2 on the right surface and what we know + + align:start position:0% +C2 on the right surface and what we know + + + align:start position:0% +C2 on the right surface and what we know +is we expect that after some period of + + align:start position:0% +is we expect that after some period of + + + align:start position:0% +is we expect that after some period of +time if if C1 is held constant if C1 is + + align:start position:0% +time if if C1 is held constant if C1 is + + + align:start position:0% +time if if C1 is held constant if C1 is +held constant and C2 is held constant + + align:start position:0% +held constant and C2 is held constant + + + align:start position:0% +held constant and C2 is held constant +then after some period of time we expect + + align:start position:0% +then after some period of time we expect + + + align:start position:0% +then after some period of time we expect +to have a profile that is linear we + + align:start position:0% +to have a profile that is linear we + + + align:start position:0% +to have a profile that is linear we +expect to have a profile that is linear + + align:start position:0% +expect to have a profile that is linear + + + align:start position:0% +expect to have a profile that is linear +and we should be able to uh infer that + + align:start position:0% +and we should be able to uh infer that + + + align:start position:0% +and we should be able to uh infer that +from fixed first law we know that fixed + + align:start position:0% +from fixed first law we know that fixed + + + align:start position:0% +from fixed first law we know that fixed +first law tells us that J is equal to + + align:start position:0% +first law tells us that J is equal to + + + align:start position:0% +first law tells us that J is equal to +minus D DC by + + align:start position:0% +minus D DC by + + + align:start position:0% +minus D DC by +DX + + align:start position:0% +DX + + + align:start position:0% +DX +so if I'm + + align:start position:0% +so if I'm + + + align:start position:0% +so if I'm +holding the concentrations on both sides + + align:start position:0% +holding the concentrations on both sides + + + align:start position:0% +holding the concentrations on both sides +sides constant then it tells me then + + align:start position:0% +sides constant then it tells me then + + + align:start position:0% +sides constant then it tells me then +that the gradient is going to be + + align:start position:0% +that the gradient is going to be + + + align:start position:0% +that the gradient is going to be +constant otherwise I have some sources + + align:start position:0% +constant otherwise I have some sources + + + align:start position:0% +constant otherwise I have some sources +or syns which uh we don't allow for so + + align:start position:0% +or syns which uh we don't allow for so + + + align:start position:0% +or syns which uh we don't allow for so +after this short time we have this + + align:start position:0% +after this short time we have this + + + align:start position:0% +after this short time we have this +profile which we term steady + + align:start position:0% +profile which we term steady + + + align:start position:0% +profile which we term steady +state steady state and it's term steady + + align:start position:0% +state steady state and it's term steady + + + align:start position:0% +state steady state and it's term steady +state because it's invariant with time + + align:start position:0% +state because it's invariant with time + + + align:start position:0% +state because it's invariant with time +the flux is not a function of time the + + align:start position:0% +the flux is not a function of time the + + + align:start position:0% +the flux is not a function of time the +flux entering the free surface on the + + align:start position:0% +flux entering the free surface on the + + + align:start position:0% +flux entering the free surface on the +left equals the flux exiting on the free + + align:start position:0% +left equals the flux exiting on the free + + + align:start position:0% +left equals the flux exiting on the free +surface on the right and therefore the + + align:start position:0% +surface on the right and therefore the + + + align:start position:0% +surface on the right and therefore the +flux must be constant throughout the + + align:start position:0% +flux must be constant throughout the + + + align:start position:0% +flux must be constant throughout the +membrane because if J is constant and + + align:start position:0% +membrane because if J is constant and + + + align:start position:0% +membrane because if J is constant and +I'm assuming that the diffusion + + align:start position:0% +I'm assuming that the diffusion + + + align:start position:0% +I'm assuming that the diffusion +coefficient doesn't change with time + + align:start position:0% +coefficient doesn't change with time + + + align:start position:0% +coefficient doesn't change with time +then it means that this gradient must be + + align:start position:0% +then it means that this gradient must be + + + align:start position:0% +then it means that this gradient must be +constant so the slope must be the same + + align:start position:0% +constant so the slope must be the same + + + align:start position:0% +constant so the slope must be the same +all the way along reinforcing the notion + + align:start position:0% +all the way along reinforcing the notion + + + align:start position:0% +all the way along reinforcing the notion +that we have a straight line + + align:start position:0% +that we have a straight line + + + align:start position:0% +that we have a straight line +profile now there's one assumption here + + align:start position:0% +profile now there's one assumption here + + + align:start position:0% +profile now there's one assumption here +of course and that is that the diffusion + + align:start position:0% +of course and that is that the diffusion + + + align:start position:0% +of course and that is that the diffusion +coefficient is independent of + + align:start position:0% +coefficient is independent of + + + align:start position:0% +coefficient is independent of +concentration it could be and we'll + + align:start position:0% +concentration it could be and we'll + + + align:start position:0% +concentration it could be and we'll +return to that later and see what + + align:start position:0% +return to that later and see what + + + align:start position:0% +return to that later and see what +happens if we have the uh concentration + + align:start position:0% +happens if we have the uh concentration + + + align:start position:0% +happens if we have the uh concentration +dependent diffusivity we can describe at + + align:start position:0% +dependent diffusivity we can describe at + + + align:start position:0% +dependent diffusivity we can describe at +steady state everything we need to know + + align:start position:0% +steady state everything we need to know + + + align:start position:0% +steady state everything we need to know +about the behavior of this system with + + align:start position:0% +about the behavior of this system with + + + align:start position:0% +about the behavior of this system with +fixed first law alone fixed first law + + align:start position:0% +fixed first law alone fixed first law + + + align:start position:0% +fixed first law alone fixed first law +alone is sufficient so one of the kinds + + align:start position:0% +alone is sufficient so one of the kinds + + + align:start position:0% +alone is sufficient so one of the kinds +of things that we might want to know we + + align:start position:0% +of things that we might want to know we + + + align:start position:0% +of things that we might want to know we +might want to ask is um oh how much + + align:start position:0% +might want to ask is um oh how much + + + align:start position:0% +might want to ask is um oh how much +material uh diffuses over time okay Mass + + align:start position:0% +material uh diffuses over time okay Mass + + + align:start position:0% +material uh diffuses over time okay Mass +per unit + + align:start position:0% +per unit + + + align:start position:0% +per unit +time passing through the + + align:start position:0% +time passing through the + + + align:start position:0% +time passing through the +membrane passing through the membrane + + align:start position:0% +membrane passing through the membrane + + + align:start position:0% +membrane passing through the membrane +all we need is fixed first law because + + align:start position:0% +all we need is fixed first law because + + + align:start position:0% +all we need is fixed first law because +we know that we can say that that um the + + align:start position:0% +we know that we can say that that um the + + + align:start position:0% +we know that we can say that that um the +mass will simply equal the flux which is + + align:start position:0% +mass will simply equal the flux which is + + + align:start position:0% +mass will simply equal the flux which is +mass per unit area per unit time if I + + align:start position:0% +mass per unit area per unit time if I + + + align:start position:0% +mass per unit area per unit time if I +know the total area of the membrane and + + align:start position:0% +know the total area of the membrane and + + + align:start position:0% +know the total area of the membrane and +I know the time then that's all I need + + align:start position:0% +I know the time then that's all I need + + + align:start position:0% +I know the time then that's all I need +so fixed first law is very + + align:start position:0% +so fixed first law is very + + + align:start position:0% +so fixed first law is very +uh thorough in describing system at + + align:start position:0% +uh thorough in describing system at + + + align:start position:0% +uh thorough in describing system at +steady state um last thing about this + + align:start position:0% +steady state um last thing about this + + + align:start position:0% +steady state um last thing about this +concentration + + align:start position:0% +concentration + + + align:start position:0% +concentration +profile the operative definition of + + align:start position:0% +profile the operative definition of + + + align:start position:0% +profile the operative definition of +steady state is that J doesn't change + + align:start position:0% +steady state is that J doesn't change + + + align:start position:0% +steady state is that J doesn't change +with time in other words if I look at + + align:start position:0% +with time in other words if I look at + + + align:start position:0% +with time in other words if I look at +this some later time as long as I + + align:start position:0% +this some later time as long as I + + + align:start position:0% +this some later time as long as I +maintain constant n compositions I'll + + align:start position:0% +maintain constant n compositions I'll + + + align:start position:0% +maintain constant n compositions I'll +have this same profile but suppose I had + + align:start position:0% +have this same profile but suppose I had + + + align:start position:0% +have this same profile but suppose I had +a situation like this where the + + align:start position:0% +a situation like this where the + + + align:start position:0% +a situation like this where the +diffusion coefficient is not independent + + align:start position:0% +diffusion coefficient is not independent + + + align:start position:0% +diffusion coefficient is not independent +of concentration I'll give you an + + align:start position:0% +of concentration I'll give you an + + + align:start position:0% +of concentration I'll give you an +example um uh diffusion coefficient of + + align:start position:0% +example um uh diffusion coefficient of + + + align:start position:0% +example um uh diffusion coefficient of +carbon in Iron this is steel diffusion + + align:start position:0% +carbon in Iron this is steel diffusion + + + align:start position:0% +carbon in Iron this is steel diffusion +coefficient of carbon in Iron as a + + align:start position:0% +coefficient of carbon in Iron as a + + + align:start position:0% +coefficient of carbon in Iron as a +function of the concentration of carbon + + align:start position:0% +function of the concentration of carbon + + + align:start position:0% +function of the concentration of carbon +in + + align:start position:0% +in + + + align:start position:0% +in +iron it turns out that as more and more + + align:start position:0% +iron it turns out that as more and more + + + align:start position:0% +iron it turns out that as more and more +carbon goes into iron the diffusion + + align:start position:0% +carbon goes into iron the diffusion + + + align:start position:0% +carbon goes into iron the diffusion +coefficient changes you'd expect that + + align:start position:0% +coefficient changes you'd expect that + + + align:start position:0% +coefficient changes you'd expect that +because now some of the SES are occupied + + align:start position:0% +because now some of the SES are occupied + + + align:start position:0% +because now some of the SES are occupied +right so which is it do you think that + + align:start position:0% +right so which is it do you think that + + + align:start position:0% +right so which is it do you think that +the diffusion coefficient as you get + + align:start position:0% +the diffusion coefficient as you get + + + align:start position:0% +the diffusion coefficient as you get +more and more carbon into iron start + + align:start position:0% +more and more carbon into iron start + + + align:start position:0% +more and more carbon into iron start +starts to fall like + + align:start position:0% +starts to fall like + + + align:start position:0% +starts to fall like +this or do you think the diffusion + + align:start position:0% +this or do you think the diffusion + + + align:start position:0% +this or do you think the diffusion +coefficient Rises like this so that at + + align:start position:0% +coefficient Rises like this so that at + + + align:start position:0% +coefficient Rises like this so that at +higher concentrations it becomes more + + align:start position:0% +higher concentrations it becomes more + + + align:start position:0% +higher concentrations it becomes more +difficult to diffuse well this might + + align:start position:0% +difficult to diffuse well this might + + + align:start position:0% +difficult to diffuse well this might +sound appealing because the SES are + + align:start position:0% +sound appealing because the SES are + + + align:start position:0% +sound appealing because the SES are +getting blocked makes sense right + + align:start position:0% +getting blocked makes sense right + + + align:start position:0% +getting blocked makes sense right +there's fewer empty SES but in point of + + align:start position:0% +there's fewer empty SES but in point of + + + align:start position:0% +there's fewer empty SES but in point of +fact the diffusion coefficient actually + + align:start position:0% +fact the diffusion coefficient actually + + + align:start position:0% +fact the diffusion coefficient actually +Rises why well I've told you that the + + align:start position:0% +Rises why well I've told you that the + + + align:start position:0% +Rises why well I've told you that the +carbon atom is larger than the + + align:start position:0% +carbon atom is larger than the + + + align:start position:0% +carbon atom is larger than the +interstitial site so when the carbons go + + align:start position:0% +interstitial site so when the carbons go + + + align:start position:0% +interstitial site so when the carbons go +into the interstitial sites they act as + + align:start position:0% +into the interstitial sites they act as + + + align:start position:0% +into the interstitial sites they act as +wedges and they actually wedge open the + + align:start position:0% +wedges and they actually wedge open the + + + align:start position:0% +wedges and they actually wedge open the +system and make it easier for the + + align:start position:0% +system and make it easier for the + + + align:start position:0% +system and make it easier for the +succeeding atoms to diffuse through so + + align:start position:0% +succeeding atoms to diffuse through so + + + align:start position:0% +succeeding atoms to diffuse through so +in point of fact this is what happens + + align:start position:0% +in point of fact this is what happens + + + align:start position:0% +in point of fact this is what happens +but it's could be either so let's + + align:start position:0% +but it's could be either so let's + + + align:start position:0% +but it's could be either so let's +imagine suppose we have case number one + + align:start position:0% +imagine suppose we have case number one + + + align:start position:0% +imagine suppose we have case number one +where the diffusion coefficient uh Falls + + align:start position:0% +where the diffusion coefficient uh Falls + + + align:start position:0% +where the diffusion coefficient uh Falls +as concentration Rises and now I've got + + align:start position:0% +as concentration Rises and now I've got + + + align:start position:0% +as concentration Rises and now I've got +a steady state concentration profile + + align:start position:0% +a steady state concentration profile + + + align:start position:0% +a steady state concentration profile +I've got C1 constant on the left C D2 + + align:start position:0% +I've got C1 constant on the left C D2 + + + align:start position:0% +I've got C1 constant on the left C D2 +constant on the right here's the + + align:start position:0% +constant on the right here's the + + + align:start position:0% +constant on the right here's the +equation we have to look at minus D DC + + align:start position:0% +equation we have to look at minus D DC + + + align:start position:0% +equation we have to look at minus D DC +by DX but this is now a function of + + align:start position:0% +by DX but this is now a function of + + + align:start position:0% +by DX but this is now a function of +concentration so when concentration if I + + align:start position:0% +concentration so when concentration if I + + + align:start position:0% +concentration so when concentration if I +have case number one when I have the + + align:start position:0% +have case number one when I have the + + + align:start position:0% +have case number one when I have the +highest concentration up here if this is + + align:start position:0% +highest concentration up here if this is + + + align:start position:0% +highest concentration up here if this is +going to remain constant if the + + align:start position:0% +going to remain constant if the + + + align:start position:0% +going to remain constant if the +concentration the dependence of the + + align:start position:0% +concentration the dependence of the + + + align:start position:0% +concentration the dependence of the +diffusion coefficient says D is low when + + align:start position:0% +diffusion coefficient says D is low when + + + align:start position:0% +diffusion coefficient says D is low when +C is high then that suggest ask them to + + align:start position:0% +C is high then that suggest ask them to + + + align:start position:0% +C is high then that suggest ask them to +keep a + + align:start position:0% +keep a + + + align:start position:0% +keep a +constant flux DC DX must be high when C + + align:start position:0% +constant flux DC DX must be high when C + + + align:start position:0% +constant flux DC DX must be high when C +is high so that means instead of a + + align:start position:0% +is high so that means instead of a + + + align:start position:0% +is high so that means instead of a +straight line we are going to see + + align:start position:0% +straight line we are going to see + + + align:start position:0% +straight line we are going to see +something that looks like this so this + + align:start position:0% +something that looks like this so this + + + align:start position:0% +something that looks like this so this +is case number one how about case number + + align:start position:0% +is case number one how about case number + + + align:start position:0% +is case number one how about case number +two where the concentration dependence + + align:start position:0% +two where the concentration dependence + + + align:start position:0% +two where the concentration dependence +of the diffusivity is indicated with a + + align:start position:0% +of the diffusivity is indicated with a + + + align:start position:0% +of the diffusivity is indicated with a +rise well that means at high + + align:start position:0% +rise well that means at high + + + align:start position:0% +rise well that means at high +concentration my diffusion coefficient + + align:start position:0% +concentration my diffusion coefficient + + + align:start position:0% +concentration my diffusion coefficient +is going to be higher than it is at low + + align:start position:0% +is going to be higher than it is at low + + + align:start position:0% +is going to be higher than it is at low +concentration so if this number is + + align:start position:0% +concentration so if this number is + + + align:start position:0% +concentration so if this number is +higher + + align:start position:0% +higher + + + align:start position:0% +higher +at high concentration then this number + + align:start position:0% +at high concentration then this number + + + align:start position:0% +at high concentration then this number +has to be lower so that the product will + + align:start position:0% +has to be lower so that the product will + + + align:start position:0% +has to be lower so that the product will +remain constant the product will remain + + align:start position:0% +remain constant the product will remain + + + align:start position:0% +remain constant the product will remain +constant so this is case number + + align:start position:0% +constant so this is case number + + + align:start position:0% +constant so this is case number +two so these are all variants of steady + + align:start position:0% + + + + align:start position:0% + +state steady state J is not a function + + align:start position:0% +state steady state J is not a function + + + align:start position:0% +state steady state J is not a function +of time J is not a function of time + + align:start position:0% +of time J is not a function of time + + + align:start position:0% +of time J is not a function of time +independent of time so now I want to ask + + align:start position:0% +independent of time so now I want to ask + + + align:start position:0% +independent of time so now I want to ask +what happens in that initial moment when + + align:start position:0% +what happens in that initial moment when + + + align:start position:0% +what happens in that initial moment when +we first first pressurize the system + + align:start position:0% +we first first pressurize the system + + + align:start position:0% +we first first pressurize the system +let's say we start off and there's + + align:start position:0% +let's say we start off and there's + + + align:start position:0% +let's say we start off and there's +nothing inside + + align:start position:0% +nothing inside + + + align:start position:0% +nothing inside +the membrane and just to keep things + + align:start position:0% +the membrane and just to keep things + + + align:start position:0% +the membrane and just to keep things +simple I'm going to make uh P equals z + + align:start position:0% +simple I'm going to make uh P equals z + + + align:start position:0% +simple I'm going to make uh P equals z +on the right hand side so left side is + + align:start position:0% +on the right hand side so left side is + + + align:start position:0% +on the right hand side so left side is +P1 and at Time Zero we initially + + align:start position:0% +P1 and at Time Zero we initially + + + align:start position:0% +P1 and at Time Zero we initially +pressurize we have a concentration C1 + + align:start position:0% +pressurize we have a concentration C1 + + + align:start position:0% +pressurize we have a concentration C1 +instantly at the surface what's the set + + align:start position:0% +instantly at the surface what's the set + + + align:start position:0% +instantly at the surface what's the set +of events that occurs leading up to the + + align:start position:0% +of events that occurs leading up to the + + + align:start position:0% +of events that occurs leading up to the +establishment of the steady state + + align:start position:0% +establishment of the steady state + + + align:start position:0% +establishment of the steady state +profile we'd expect after a short time + + align:start position:0% +profile we'd expect after a short time + + + align:start position:0% +profile we'd expect after a short time +we'd see concentration profile showing + + align:start position:0% +we'd see concentration profile showing + + + align:start position:0% +we'd see concentration profile showing +like this and then after a longer period + + align:start position:0% +like this and then after a longer period + + + align:start position:0% +like this and then after a longer period +of time like this and then after a + + align:start position:0% +of time like this and then after a + + + align:start position:0% +of time like this and then after a +longer period of time like this and then + + align:start position:0% +longer period of time like this and then + + + align:start position:0% +longer period of time like this and then +finally of + + align:start position:0% +finally of + + + align:start position:0% +finally of +course we establish so this is time is + + align:start position:0% +course we establish so this is time is + + + align:start position:0% +course we establish so this is time is +increasing from low to high so this + + align:start position:0% +increasing from low to high so this + + + align:start position:0% +increasing from low to high so this +could be T1 T2 T3 and so we can then say + + align:start position:0% +could be T1 T2 T3 and so we can then say + + + align:start position:0% +could be T1 T2 T3 and so we can then say +let's park ourselves at some value X1 on + + align:start position:0% +let's park ourselves at some value X1 on + + + align:start position:0% +let's park ourselves at some value X1 on +Zer to L and look at what's happening + + align:start position:0% +Zer to L and look at what's happening + + + align:start position:0% +Zer to L and look at what's happening +initially if I take the slope it's a + + align:start position:0% +initially if I take the slope it's a + + + align:start position:0% +initially if I take the slope it's a +it's a low number if I take the slope at + + align:start position:0% +it's a low number if I take the slope at + + + align:start position:0% +it's a low number if I take the slope at +a later time it's a higher number if I + + align:start position:0% +a later time it's a higher number if I + + + align:start position:0% +a later time it's a higher number if I +take the slope at a later time it's an + + align:start position:0% +take the slope at a later time it's an + + + align:start position:0% +take the slope at a later time it's an +even higher number and ultimately it's + + align:start position:0% +even higher number and ultimately it's + + + align:start position:0% +even higher number and ultimately it's +going to be as high as the steady state + + align:start position:0% +going to be as high as the steady state + + + align:start position:0% +going to be as high as the steady state +value so I could take that data set and + + align:start position:0% +value so I could take that data set and + + + align:start position:0% +value so I could take that data set and +plot the flux + + align:start position:0% +plot the flux + + + align:start position:0% +plot the flux +at xal X1 I'm sitting here and watching + + align:start position:0% +at xal X1 I'm sitting here and watching + + + align:start position:0% +at xal X1 I'm sitting here and watching +the + + align:start position:0% +the + + + align:start position:0% +the +the profile evolve with time initially + + align:start position:0% +the profile evolve with time initially + + + align:start position:0% +the profile evolve with time initially +it's zero because there's nothing in the + + align:start position:0% +it's zero because there's nothing in the + + + align:start position:0% +it's zero because there's nothing in the +in the uh membrane and then it slowly + + align:start position:0% +in the uh membrane and then it slowly + + + align:start position:0% +in the uh membrane and then it slowly +Rises and reaches the steady state value + + align:start position:0% +Rises and reaches the steady state value + + + align:start position:0% +Rises and reaches the steady state value +so this is this is J at steady state + + align:start position:0% +so this is this is J at steady state + + + align:start position:0% +so this is this is J at steady state +here J at steady state and this could be + + align:start position:0% +here J at steady state and this could be + + + align:start position:0% +here J at steady state and this could be +T1 T2 and T3 so you can see that coming + + align:start position:0% +T1 T2 and T3 so you can see that coming + + + align:start position:0% +T1 T2 and T3 so you can see that coming +off the + + align:start position:0% +off the + + + align:start position:0% +off the +slope so clearly when we're moving + + align:start position:0% +slope so clearly when we're moving + + + align:start position:0% +slope so clearly when we're moving +through this time period + + align:start position:0% +through this time period + + + align:start position:0% +through this time period +J is very much a function of time + + align:start position:0% +J is very much a function of time + + + align:start position:0% +J is very much a function of time +because if you close your eyes and wait + + align:start position:0% +because if you close your eyes and wait + + + align:start position:0% +because if you close your eyes and wait +you'll see that the profile has changed + + align:start position:0% +you'll see that the profile has changed + + + align:start position:0% +you'll see that the profile has changed +and if the profile has changed it means + + align:start position:0% +and if the profile has changed it means + + + align:start position:0% +and if the profile has changed it means +that the instant value of flux is + + align:start position:0% +that the instant value of flux is + + + align:start position:0% +that the instant value of flux is +changed so flux is a function of time so + + align:start position:0% +changed so flux is a function of time so + + + align:start position:0% +changed so flux is a function of time so +this is not steady state this is + + align:start position:0% +this is not steady state this is + + + align:start position:0% +this is not steady state this is +not steady state instead it is transient + + align:start position:0% +not steady state instead it is transient + + + align:start position:0% +not steady state instead it is transient +we're in the transient + + align:start position:0% + + + + align:start position:0% + +regime transient regime + + align:start position:0% +regime transient regime + + + align:start position:0% +regime transient regime +and + + align:start position:0% +and + + + align:start position:0% +and +so as is always the case we can draw + + align:start position:0% +so as is always the case we can draw + + + align:start position:0% +so as is always the case we can draw +these curves they start at a high value + + align:start position:0% +these curves they start at a high value + + + align:start position:0% +these curves they start at a high value +they attenuate to zero What's the + + align:start position:0% +they attenuate to zero What's the + + + align:start position:0% +they attenuate to zero What's the +magical question what is the shape what + + align:start position:0% +magical question what is the shape what + + + align:start position:0% +magical question what is the shape what +is the shape that's the only reason I + + align:start position:0% +is the shape that's the only reason I + + + align:start position:0% +is the shape that's the only reason I +need math to tell me the shape of those + + align:start position:0% +need math to tell me the shape of those + + + align:start position:0% +need math to tell me the shape of those +curves is is this a an exponential decay + + align:start position:0% +curves is is this a an exponential decay + + + align:start position:0% +curves is is this a an exponential decay +is this half of a sinusoid what is the + + align:start position:0% +is this half of a sinusoid what is the + + + align:start position:0% +is this half of a sinusoid what is the +shape of the curves I want to know C + + align:start position:0% +shape of the curves I want to know C + + + align:start position:0% +shape of the curves I want to know C +versus X at all times at all times + + align:start position:0% +versus X at all times at all times + + + align:start position:0% +versus X at all times at all times +because it's changing as a function of + + align:start position:0% +because it's changing as a function of + + + align:start position:0% +because it's changing as a function of +time that means I need to know c as a + + align:start position:0% +time that means I need to know c as a + + + align:start position:0% +time that means I need to know c as a +function of x and t I've got to solve + + align:start position:0% +function of x and t I've got to solve + + + align:start position:0% +function of x and t I've got to solve +this and fi gave us the solution to this + + align:start position:0% +this and fi gave us the solution to this + + + align:start position:0% +this and fi gave us the solution to this +as + + align:start position:0% +as + + + align:start position:0% +as +well the solution of this is the + + align:start position:0% +well the solution of this is the + + + align:start position:0% +well the solution of this is the +solution to an + + align:start position:0% +solution to an + + + align:start position:0% +solution to an +equation known as fix Second Law so + + align:start position:0% +equation known as fix Second Law so + + + align:start position:0% +equation known as fix Second Law so +let's look at fixed Second + + align:start position:0% + + + + align:start position:0% + +Law fix second law + + align:start position:0% +Law fix second law + + + align:start position:0% +Law fix second law +and I'm going to write it in the special + + align:start position:0% +and I'm going to write it in the special + + + align:start position:0% +and I'm going to write it in the special +casee when D is independent of + + align:start position:0% +casee when D is independent of + + + align:start position:0% +casee when D is independent of +composition D has to be independent of + + align:start position:0% +composition D has to be independent of + + + align:start position:0% +composition D has to be independent of +composition for me to do what I'm going + + align:start position:0% +composition for me to do what I'm going + + + align:start position:0% +composition for me to do what I'm going +to do next and it's a pretty good + + align:start position:0% +to do next and it's a pretty good + + + align:start position:0% +to do next and it's a pretty good +assumption in many industrial settings + + align:start position:0% +assumption in many industrial settings + + + align:start position:0% +assumption in many industrial settings +and so I'm just going to write it it's a + + align:start position:0% +and so I'm just going to write it it's a + + + align:start position:0% +and so I'm just going to write it it's a +partial differential + + align:start position:0% + + + + align:start position:0% + +equation and so what it's telling you is + + align:start position:0% +equation and so what it's telling you is + + + align:start position:0% +equation and so what it's telling you is +that the partial with respect to time is + + align:start position:0% +that the partial with respect to time is + + + align:start position:0% +that the partial with respect to time is +equal to the product of the diffusion + + align:start position:0% +equal to the product of the diffusion + + + align:start position:0% +equal to the product of the diffusion +coefficient times the partial of the + + align:start position:0% +coefficient times the partial of the + + + align:start position:0% +coefficient times the partial of the +gradient in concentration and so clearly + + align:start position:0% +gradient in concentration and so clearly + + + align:start position:0% +gradient in concentration and so clearly +this is a partial differential equation + + align:start position:0% +this is a partial differential equation + + + align:start position:0% +this is a partial differential equation +and that's bad that's bad you can't + + align:start position:0% +and that's bad that's bad you can't + + + align:start position:0% +and that's bad that's bad you can't +solve this one not yet okay but the good + + align:start position:0% +solve this one not yet okay but the good + + + align:start position:0% +solve this one not yet okay but the good +news is it's a linear partial + + align:start position:0% +news is it's a linear partial + + + align:start position:0% +news is it's a linear partial +differential equation and that's good + + align:start position:0% +differential equation and that's good + + + align:start position:0% +differential equation and that's good +because I can show you a solution that + + align:start position:0% +because I can show you a solution that + + + align:start position:0% +because I can show you a solution that +applies for a given setting and then you + + align:start position:0% +applies for a given setting and then you + + + align:start position:0% +applies for a given setting and then you +can play with the boundary conditions + + align:start position:0% +can play with the boundary conditions + + + align:start position:0% +can play with the boundary conditions +and use the same solu solution so that's + + align:start position:0% +and use the same solu solution so that's + + + align:start position:0% +and use the same solu solution so that's +the good news it's linear all right so + + align:start position:0% +the good news it's linear all right so + + + align:start position:0% +the good news it's linear all right so +um but the solution to this is both in x + + align:start position:0% +um but the solution to this is both in x + + + align:start position:0% +um but the solution to this is both in x +and + + align:start position:0% +and + + + align:start position:0% +and +t and the solution looks like this + + align:start position:0% +t and the solution looks like this + + + align:start position:0% +t and the solution looks like this +solution looks like + + align:start position:0% +solution looks like + + + align:start position:0% +solution looks like +this let's say we have an initial + + align:start position:0% +this let's say we have an initial + + + align:start position:0% +this let's say we have an initial +concentration c + + align:start position:0% +concentration c + + + align:start position:0% +concentration c +not C is a function of X so I have an + + align:start position:0% +not C is a function of X so I have an + + + align:start position:0% +not C is a function of X so I have an +initial nonzero concentration c not and + + align:start position:0% +initial nonzero concentration c not and + + + align:start position:0% +initial nonzero concentration c not and +I have a surface concentration fixed at + + align:start position:0% +I have a surface concentration fixed at + + + align:start position:0% +I have a surface concentration fixed at +Cs and this is the system that we're + + align:start position:0% +Cs and this is the system that we're + + + align:start position:0% +Cs and this is the system that we're +trying to model and the general + + align:start position:0% +trying to model and the general + + + align:start position:0% +trying to model and the general +solution the general solution to fixed + + align:start position:0% +solution the general solution to fixed + + + align:start position:0% +solution the general solution to fixed +Second Law is C of x and t is some + + align:start position:0% +Second Law is C of x and t is some + + + align:start position:0% +Second Law is C of x and t is some +constant a plus a constant B times a + + align:start position:0% +constant a plus a constant B times a + + + align:start position:0% +constant a plus a constant B times a +function which I'm going to Define for + + align:start position:0% +function which I'm going to Define for + + + align:start position:0% +function which I'm going to Define for +you in a second the error function + + align:start position:0% +you in a second the error function + + + align:start position:0% +you in a second the error function +gaussian error function of x / square + + align:start position:0% +gaussian error function of x / square + + + align:start position:0% +gaussian error function of x / square +roots of DT so these are both constants + + align:start position:0% +roots of DT so these are both constants + + + align:start position:0% +roots of DT so these are both constants +to be determined this is the gaussian + + align:start position:0% +to be determined this is the gaussian + + + align:start position:0% +to be determined this is the gaussian +error + + align:start position:0% +error + + + align:start position:0% +error +function the error function X's + + align:start position:0% +function the error function X's + + + align:start position:0% +function the error function X's +position T is time and D is the + + align:start position:0% +position T is time and D is the + + + align:start position:0% +position T is time and D is the +diffusion coefficient and this is + + align:start position:0% +diffusion coefficient and this is + + + align:start position:0% +diffusion coefficient and this is +nothing but a transcendental function + + align:start position:0% +nothing but a transcendental function + + + align:start position:0% +nothing but a transcendental function +that varies from 0 to one and you know I + + align:start position:0% +that varies from 0 to one and you know I + + + align:start position:0% +that varies from 0 to one and you know I +could have said s if I said it's sin x + + align:start position:0% +could have said s if I said it's sin x + + + align:start position:0% +could have said s if I said it's sin x +over uh 2 roots of DT you know the the + + align:start position:0% +over uh 2 roots of DT you know the the + + + align:start position:0% +over uh 2 roots of DT you know the the +definition of s it's got some weird + + align:start position:0% +definition of s it's got some weird + + + align:start position:0% +definition of s it's got some weird +integral and blah blah blah nobody pays + + align:start position:0% +integral and blah blah blah nobody pays + + + align:start position:0% +integral and blah blah blah nobody pays +any attention to it you know it goes + + align:start position:0% +any attention to it you know it goes + + + align:start position:0% +any attention to it you know it goes +from 0 to one it's linear low values of + + align:start position:0% +from 0 to one it's linear low values of + + + align:start position:0% +from 0 to one it's linear low values of +theta so what so we're going to learn + + align:start position:0% +theta so what so we're going to learn + + + align:start position:0% +theta so what so we're going to learn +what the properties of this are but I + + align:start position:0% +what the properties of this are but I + + + align:start position:0% +what the properties of this are but I +can tell you something right off the bat + + align:start position:0% +can tell you something right off the bat + + + align:start position:0% +can tell you something right off the bat +what do you think the shape of the error + + align:start position:0% +what do you think the shape of the error + + + align:start position:0% +what do you think the shape of the error +function is what's the shape of the + + align:start position:0% +function is what's the shape of the + + + align:start position:0% +function is what's the shape of the +error function that's the shape that's + + align:start position:0% +error function that's the shape that's + + + align:start position:0% +error function that's the shape that's +the shape okay that's what math is math + + align:start position:0% +the shape okay that's what math is math + + + align:start position:0% +the shape okay that's what math is math +is finding the + + align:start position:0% +is finding the + + + align:start position:0% +is finding the +shape otherwise doesn't make any sense + + align:start position:0% +shape otherwise doesn't make any sense + + + align:start position:0% +shape otherwise doesn't make any sense +and what are these These are scale + + align:start position:0% +and what are these These are scale + + + align:start position:0% +and what are these These are scale +factors you know you've done this on a + + align:start position:0% +factors you know you've done this on a + + + align:start position:0% +factors you know you've done this on a +computer where you take some image and + + align:start position:0% +computer where you take some image and + + + align:start position:0% +computer where you take some image and +you pull it you stretch it and so on and + + align:start position:0% +you pull it you stretch it and so on and + + + align:start position:0% +you pull it you stretch it and so on and +you can lock the aspect ratio right can + + align:start position:0% +you can lock the aspect ratio right can + + + align:start position:0% +you can lock the aspect ratio right can +lock the aspect R well that's all you're + + align:start position:0% +lock the aspect R well that's all you're + + + align:start position:0% +lock the aspect R well that's all you're +doing here mathematically we're going to + + align:start position:0% +doing here mathematically we're going to + + + align:start position:0% +doing here mathematically we're going to +pull this why are we going to pull it + + align:start position:0% +pull this why are we going to pull it + + + align:start position:0% +pull this why are we going to pull it +because at a later time it looks like + + align:start position:0% +because at a later time it looks like + + + align:start position:0% +because at a later time it looks like +this but the relationship between all of + + align:start position:0% +this but the relationship between all of + + + align:start position:0% +this but the relationship between all of +these points is the same so that's what + + align:start position:0% +these points is the same so that's what + + + align:start position:0% +these points is the same so that's what +math does if it doesn't fire it you know + + align:start position:0% +math does if it doesn't fire it you know + + + align:start position:0% +math does if it doesn't fire it you know +math works for you you don't work for + + align:start position:0% +math works for you you don't work for + + + align:start position:0% +math works for you you don't work for +math so let's put this thing to work + + align:start position:0% +math so let's put this thing to work + + + align:start position:0% +math so let's put this thing to work +lazy right so what we're going to do is + + align:start position:0% +lazy right so what we're going to do is + + + align:start position:0% +lazy right so what we're going to do is +we have to solve for A and B now you + + align:start position:0% +we have to solve for A and B now you + + + align:start position:0% +we have to solve for A and B now you +know that when you uh when you + + align:start position:0% +know that when you uh when you + + + align:start position:0% +know that when you uh when you +differentiate you throw away information + + align:start position:0% +differentiate you throw away information + + + align:start position:0% +differentiate you throw away information +all right so every time you throw away + + align:start position:0% +all right so every time you throw away + + + align:start position:0% +all right so every time you throw away +information we need to add some so we + + align:start position:0% +information we need to add some so we + + + align:start position:0% +information we need to add some so we +need to have one time based boundary + + align:start position:0% +need to have one time based boundary + + + align:start position:0% +need to have one time based boundary +condition and we need to have two + + align:start position:0% +condition and we need to have two + + + align:start position:0% +condition and we need to have two +spatially based boundary conditions + + align:start position:0% +spatially based boundary conditions + + + align:start position:0% +spatially based boundary conditions +because we threw away three bits of + + align:start position:0% +because we threw away three bits of + + + align:start position:0% +because we threw away three bits of +information so that's what we're going + + align:start position:0% +information so that's what we're going + + + align:start position:0% +information so that's what we're going +to do and if we go ahead and do that + + align:start position:0% +to do and if we go ahead and do that + + + align:start position:0% +to do and if we go ahead and do that +here's what the uh A and B will solve to + + align:start position:0% +here's what the uh A and B will solve to + + + align:start position:0% +here's what the uh A and B will solve to +and this works for all cases C minus the + + align:start position:0% +and this works for all cases C minus the + + + align:start position:0% +and this works for all cases C minus the +surface concentration divided by the + + align:start position:0% +surface concentration divided by the + + + align:start position:0% +surface concentration divided by the +initial concentration minus the surface + + align:start position:0% +initial concentration minus the surface + + + align:start position:0% +initial concentration minus the surface +Sur concentration equals error function + + align:start position:0% +Sur concentration equals error function + + + align:start position:0% +Sur concentration equals error function +of x/ + + align:start position:0% +of x/ + + + align:start position:0% +of x/ +2 roots of DT so C is the what you're + + align:start position:0% +2 roots of DT so C is the what you're + + + align:start position:0% +2 roots of DT so C is the what you're +looking for this is c as a function of x + + align:start position:0% +looking for this is c as a function of x + + + align:start position:0% +looking for this is c as a function of x +and t CS is surface concentration Co is + + align:start position:0% +and t CS is surface concentration Co is + + + align:start position:0% +and t CS is surface concentration Co is +the uh initial concentration and let's + + align:start position:0% +the uh initial concentration and let's + + + align:start position:0% +the uh initial concentration and let's +take a look at what that + + align:start position:0% +take a look at what that + + + align:start position:0% +take a look at what that +function plots out to be so I'm going to + + align:start position:0% +function plots out to be so I'm going to + + + align:start position:0% +function plots out to be so I'm going to +plot Earth of + + align:start position:0% +plot Earth of + + + align:start position:0% +plot Earth of +Z Earth of Z as a function of Z it + + align:start position:0% +Z Earth of Z as a function of Z it + + + align:start position:0% +Z Earth of Z as a function of Z it +varies from 0 to + + align:start position:0% +varies from 0 to + + + align:start position:0% +varies from 0 to +one and it starts off like so many + + align:start position:0% +one and it starts off like so many + + + align:start position:0% +one and it starts off like so many +functions it's linear for low values of + + align:start position:0% +functions it's linear for low values of + + + align:start position:0% +functions it's linear for low values of +Z Earth of Z equals z and in fact up to + + align:start position:0% +Z Earth of Z equals z and in fact up to + + + align:start position:0% +Z Earth of Z equals z and in fact up to +about + + align:start position:0% +about + + + align:start position:0% +about +0.6 you're good to within 1% Earth of Z + + align:start position:0% +0.6 you're good to within 1% Earth of Z + + + align:start position:0% +0.6 you're good to within 1% Earth of Z +equals z to within 1% and then once it + + align:start position:0% +equals z to within 1% and then once it + + + align:start position:0% +equals z to within 1% and then once it +gets up to0 6 then it starts to Veer off + + align:start position:0% +gets up to0 6 then it starts to Veer off + + + align:start position:0% +gets up to0 6 then it starts to Veer off +and then ASM totically + + align:start position:0% +and then ASM totically + + + align:start position:0% +and then ASM totically +approach uh Earth + + align:start position:0% +approach uh Earth + + + align:start position:0% +approach uh Earth +uh Earth Z equals 1 so in fact we can + + align:start position:0% +uh Earth Z equals 1 so in fact we can + + + align:start position:0% +uh Earth Z equals 1 so in fact we can +write here Earth of Earth of one equals + + align:start position:0% +write here Earth of Earth of one equals + + + align:start position:0% +write here Earth of Earth of one equals +0.84 so you can see now it's not linear + + align:start position:0% +0.84 so you can see now it's not linear + + + align:start position:0% +0.84 so you can see now it's not linear +and Earth of two equals + + align:start position:0% +and Earth of two equals + + + align:start position:0% +and Earth of two equals +0.995 so once you get out here to two + + align:start position:0% +0.995 so once you get out here to two + + + align:start position:0% +0.995 so once you get out here to two +you're practically at the ASM toote and + + align:start position:0% +you're practically at the ASM toote and + + + align:start position:0% +you're practically at the ASM toote and +it's defined here's the integral it's + + align:start position:0% +it's defined here's the integral it's + + + align:start position:0% +it's defined here's the integral it's +defined Earth of Z is the integral from + + align:start position:0% +defined Earth of Z is the integral from + + + align:start position:0% +defined Earth of Z is the integral from +Z + + align:start position:0% +Z + + + align:start position:0% +Z +from zero Pardon Me 0 to Z of e to the + + align:start position:0% +from zero Pardon Me 0 to Z of e to the + + + align:start position:0% +from zero Pardon Me 0 to Z of e to the +minus u^2 du so that's that's this e to + + align:start position:0% +minus u^2 du so that's that's this e to + + + align:start position:0% +minus u^2 du so that's that's this e to +Theus u^ 2 e to Theus u^2 as a function + + align:start position:0% +Theus u^ 2 e to Theus u^2 as a function + + + align:start position:0% +Theus u^ 2 e to Theus u^2 as a function +of U is the gaussian error function + + align:start position:0% +of U is the gaussian error function + + + align:start position:0% +of U is the gaussian error function +right that's the bell curve so this is + + align:start position:0% +right that's the bell curve so this is + + + align:start position:0% +right that's the bell curve so this is +the area under the bell curve if we + + align:start position:0% +the area under the bell curve if we + + + align:start position:0% +the area under the bell curve if we +start at X at U equals z we're going to + + align:start position:0% +start at X at U equals z we're going to + + + align:start position:0% +start at X at U equals z we're going to +integrate as far as we need to out here + + align:start position:0% +integrate as far as we need to out here + + + align:start position:0% +integrate as far as we need to out here +and the integral from 0 to Infinity of + + align:start position:0% +and the integral from 0 to Infinity of + + + align:start position:0% +and the integral from 0 to Infinity of +this thing isun Pi / 2 two and we want + + align:start position:0% +this thing isun Pi / 2 two and we want + + + align:start position:0% +this thing isun Pi / 2 two and we want +this to go from 0 to 1 so we'll put the + + align:start position:0% +this to go from 0 to 1 so we'll put the + + + align:start position:0% +this to go from 0 to 1 so we'll put the +factor 2 overun pi out in front and that + + align:start position:0% +factor 2 overun pi out in front and that + + + align:start position:0% +factor 2 overun pi out in front and that +way when we integrate this from zero to + + align:start position:0% +way when we integrate this from zero to + + + align:start position:0% +way when we integrate this from zero to +Infinity Earth of infinity becomes one + + align:start position:0% +Infinity Earth of infinity becomes one + + + align:start position:0% +Infinity Earth of infinity becomes one +so Earth runs from 0 to one and that's + + align:start position:0% +so Earth runs from 0 to one and that's + + + align:start position:0% +so Earth runs from 0 to one and that's +the area under this curve so that's why + + align:start position:0% +the area under this curve so that's why + + + align:start position:0% +the area under this curve so that's why +some people call this the gaussian error + + align:start position:0% +some people call this the gaussian error + + + align:start position:0% +some people call this the gaussian error +function because the gaussian curve is + + align:start position:0% +function because the gaussian curve is + + + align:start position:0% +function because the gaussian curve is +associated with random statistics in + + align:start position:0% +associated with random statistics in + + + align:start position:0% +associated with random statistics in +terms of of Errors so this now is the + + align:start position:0% +terms of of Errors so this now is the + + + align:start position:0% +terms of of Errors so this now is the +template this is the template if I have + + align:start position:0% +template this is the template if I have + + + align:start position:0% +template this is the template if I have +uh any reaction this is all I have to + + align:start position:0% +uh any reaction this is all I have to + + + align:start position:0% +uh any reaction this is all I have to +fit using these um using + + align:start position:0% +fit using these um using + + + align:start position:0% +fit using these um using +these multiplication factors so let's + + align:start position:0% +these multiplication factors so let's + + + align:start position:0% +these multiplication factors so let's +play Mr dress up here and we're going to + + align:start position:0% +play Mr dress up here and we're going to + + + align:start position:0% +play Mr dress up here and we're going to +just use this function to describe all + + align:start position:0% +just use this function to describe all + + + align:start position:0% +just use this function to describe all +of the typical uh industrial processes + + align:start position:0% +of the typical uh industrial processes + + + align:start position:0% +of the typical uh industrial processes +so there's only two types of processes + + align:start position:0% +so there's only two types of processes + + + align:start position:0% +so there's only two types of processes +those that are diffusing substance in + + align:start position:0% +those that are diffusing substance in + + + align:start position:0% +those that are diffusing substance in +and then those that are pulling + + align:start position:0% +and then those that are pulling + + + align:start position:0% +and then those that are pulling +substance out so let's look at the two + + align:start position:0% +substance out so let's look at the two + + + align:start position:0% +substance out so let's look at the two +cases so let's look first of all at the + + align:start position:0% +cases so let's look first of all at the + + + align:start position:0% +cases so let's look first of all at the +one that's uh showing right up there so + + align:start position:0% +one that's uh showing right up there so + + + align:start position:0% +one that's uh showing right up there so +this would be for something like out + + align:start position:0% +this would be for something like out + + + align:start position:0% +this would be for something like out +gassing out gassing or uh drying many uh + + align:start position:0% +gassing out gassing or uh drying many uh + + + align:start position:0% +gassing out gassing or uh drying many uh +many processes involve drying which is + + align:start position:0% +many processes involve drying which is + + + align:start position:0% +many processes involve drying which is +to get the water out of the um content + + align:start position:0% +to get the water out of the um content + + + align:start position:0% +to get the water out of the um content +of a of a solid piece and so as you can + + align:start position:0% +of a of a solid piece and so as you can + + + align:start position:0% +of a of a solid piece and so as you can +imagine you've got some initial + + align:start position:0% +imagine you've got some initial + + + align:start position:0% +imagine you've got some initial +concentration C notot and you take the + + align:start position:0% +concentration C notot and you take the + + + align:start position:0% +concentration C notot and you take the +surface concentration whatever this is + + align:start position:0% +surface concentration whatever this is + + + align:start position:0% +surface concentration whatever this is +and obviously if you want to draw + + align:start position:0% +and obviously if you want to draw + + + align:start position:0% +and obviously if you want to draw +something out and move matter from right + + align:start position:0% +something out and move matter from right + + + align:start position:0% +something out and move matter from right +to left then the surface concentration + + align:start position:0% +to left then the surface concentration + + + align:start position:0% +to left then the surface concentration +by necessity must be less than the + + align:start position:0% +by necessity must be less than the + + + align:start position:0% +by necessity must be less than the +initial concentration otherwise why is + + align:start position:0% +initial concentration otherwise why is + + + align:start position:0% +initial concentration otherwise why is +something going to move so this means + + align:start position:0% +something going to move so this means + + + align:start position:0% +something going to move so this means +this I'll call + + align:start position:0% +this I'll call + + + align:start position:0% +this I'll call +effusion something is eusing so this is + + align:start position:0% +effusion something is eusing so this is + + + align:start position:0% +effusion something is eusing so this is +a fusion the flux is moving from right + + align:start position:0% +a fusion the flux is moving from right + + + align:start position:0% +a fusion the flux is moving from right +to left and the the determinant here is + + align:start position:0% +to left and the the determinant here is + + + align:start position:0% +to left and the the determinant here is +c not is greater than CS the surface + + align:start position:0% +c not is greater than CS the surface + + + align:start position:0% +c not is greater than CS the surface +concentration is less than the initial + + align:start position:0% +concentration is less than the initial + + + align:start position:0% +concentration is less than the initial +concentration so I'm going to pin the + + align:start position:0% +concentration so I'm going to pin the + + + align:start position:0% +concentration so I'm going to pin the +concentration at CS I've got c0 deep + + align:start position:0% +concentration at CS I've got c0 deep + + + align:start position:0% +concentration at CS I've got c0 deep +inside and this is telling me what the + + align:start position:0% +inside and this is telling me what the + + + align:start position:0% +inside and this is telling me what the +shape of the curve is this is telling me + + align:start position:0% +shape of the curve is this is telling me + + + align:start position:0% +shape of the curve is this is telling me +what the shape of the curve is so I just + + align:start position:0% +what the shape of the curve is so I just + + + align:start position:0% +what the shape of the curve is so I just +write with impunity cus CS over C minus + + align:start position:0% +write with impunity cus CS over C minus + + + align:start position:0% +write with impunity cus CS over C minus +CS equals error function X over two 2 + + align:start position:0% +CS equals error function X over two 2 + + + align:start position:0% +CS equals error function X over two 2 +roots of + + align:start position:0% +roots of + + + align:start position:0% +roots of +DT and that's the answer for all such + + align:start position:0% +DT and that's the answer for all such + + + align:start position:0% +DT and that's the answer for all such +problems and because it's linear it + + align:start position:0% +problems and because it's linear it + + + align:start position:0% +problems and because it's linear it +doesn't matter if I change the initial + + align:start position:0% +doesn't matter if I change the initial + + + align:start position:0% +doesn't matter if I change the initial +concentration to a new value I can just + + align:start position:0% +concentration to a new value I can just + + + align:start position:0% +concentration to a new value I can just +add we can add and multiply because it's + + align:start position:0% +add we can add and multiply because it's + + + align:start position:0% +add we can add and multiply because it's +a linear equation linear functionality + + align:start position:0% +a linear equation linear functionality + + + align:start position:0% +a linear equation linear functionality +and I think here we've got some uh oh + + align:start position:0% +and I think here we've got some uh oh + + + align:start position:0% +and I think here we've got some uh oh +yeah we looked at those this is the + + align:start position:0% +yeah we looked at those this is the + + + align:start position:0% +yeah we looked at those this is the +tabulation this is in the uh + + align:start position:0% +tabulation this is in the uh + + + align:start position:0% +tabulation this is in the uh +supplemental text there's a table of uh + + align:start position:0% +supplemental text there's a table of uh + + + align:start position:0% +supplemental text there's a table of uh +error function values so that if you + + align:start position:0% +error function values so that if you + + + align:start position:0% +error function values so that if you +happen to get into this regime Beyond um + + align:start position:0% +happen to get into this regime Beyond um + + + align:start position:0% +happen to get into this regime Beyond um +Z equals 0.6 you'll you'll have the the + + align:start position:0% +Z equals 0.6 you'll you'll have the the + + + align:start position:0% +Z equals 0.6 you'll you'll have the the +values that you + + align:start position:0% +values that you + + + align:start position:0% +values that you +need so let's look at another case let's + + align:start position:0% +need so let's look at another case let's + + + align:start position:0% +need so let's look at another case let's +look at driving material in so that for + + align:start position:0% +look at driving material in so that for + + + align:start position:0% +look at driving material in so that for +for example is something like um + + align:start position:0% + + + + align:start position:0% + +doping doping or + + align:start position:0% +doping doping or + + + align:start position:0% +doping doping or +nitriding doping nitriding + + align:start position:0% + + + + align:start position:0% + +carburising if we want to case harden a + + align:start position:0% +carburising if we want to case harden a + + + align:start position:0% +carburising if we want to case harden a +material will raise the carbon content + + align:start position:0% +material will raise the carbon content + + + align:start position:0% +material will raise the carbon content +at the free surface have something + + align:start position:0% +at the free surface have something + + + align:start position:0% +at the free surface have something +that's soft and ductile inside all right + + align:start position:0% +that's soft and ductile inside all right + + + align:start position:0% +that's soft and ductile inside all right +so for that here's the here's the scheme + + align:start position:0% +so for that here's the here's the scheme + + + align:start position:0% +so for that here's the here's the scheme +here's the scheme we have a surface + + align:start position:0% +here's the scheme we have a surface + + + align:start position:0% +here's the scheme we have a surface +concentration + + align:start position:0% +concentration + + + align:start position:0% +concentration +CS we have an initial + + align:start position:0% +CS we have an initial + + + align:start position:0% +CS we have an initial +concentration this is getting a little + + align:start position:0% +concentration this is getting a little + + + align:start position:0% +concentration this is getting a little +crowded let me clean this up surface + + align:start position:0% +crowded let me clean this up surface + + + align:start position:0% +crowded let me clean this up surface +concentration CS an initial + + align:start position:0% +concentration CS an initial + + + align:start position:0% +concentration CS an initial +concentration c not and in this case C + + align:start position:0% +concentration c not and in this case C + + + align:start position:0% +concentration c not and in this case C +not is less than CS surface + + align:start position:0% +not is less than CS surface + + + align:start position:0% +not is less than CS surface +concentration is higher so material now + + align:start position:0% +concentration is higher so material now + + + align:start position:0% +concentration is higher so material now +wants to move from left to right and so + + align:start position:0% +wants to move from left to right and so + + + align:start position:0% +wants to move from left to right and so +this is + + align:start position:0% +this is + + + align:start position:0% +this is +infusion + + align:start position:0% +infusion + + + align:start position:0% +infusion +infusion and what's the curve going to + + align:start position:0% +infusion and what's the curve going to + + + align:start position:0% +infusion and what's the curve going to +look like it looks like this looks like + + align:start position:0% +look like it looks like this looks like + + + align:start position:0% +look like it looks like this looks like +this which is simply that + + align:start position:0% +this which is simply that + + + align:start position:0% +this which is simply that +one flipped upside down by subtracting + + align:start position:0% +one flipped upside down by subtracting + + + align:start position:0% +one flipped upside down by subtracting +it from from one which I'll show you in + + align:start position:0% +it from from one which I'll show you in + + + align:start position:0% +it from from one which I'll show you in +a second and again this same general + + align:start position:0% +a second and again this same general + + + align:start position:0% +a second and again this same general +solution applies the same general + + align:start position:0% +solution applies the same general + + + align:start position:0% +solution applies the same general +solution applies whether C the surface + + align:start position:0% +solution applies whether C the surface + + + align:start position:0% +solution applies whether C the surface +concentration is higher or lower than + + align:start position:0% +concentration is higher or lower than + + + align:start position:0% +concentration is higher or lower than +the uh initial bulk concentration it + + align:start position:0% +the uh initial bulk concentration it + + + align:start position:0% +the uh initial bulk concentration it +comes out in the math here so again we + + align:start position:0% +comes out in the math here so again we + + + align:start position:0% +comes out in the math here so again we +write c - CS over c - CS equal Earth X + + align:start position:0% +write c - CS over c - CS equal Earth X + + + align:start position:0% +write c - CS over c - CS equal Earth X +over two roots of + + align:start position:0% +over two roots of + + + align:start position:0% +over two roots of +DT and this one comes up very of this is + + align:start position:0% +DT and this one comes up very of this is + + + align:start position:0% +DT and this one comes up very of this is +the way it works in doping of + + align:start position:0% +the way it works in doping of + + + align:start position:0% +the way it works in doping of +semiconductors and comes up so often + + align:start position:0% +semiconductors and comes up so often + + + align:start position:0% +semiconductors and comes up so often +that uh it it's convenient to Define uh + + align:start position:0% +that uh it it's convenient to Define uh + + + align:start position:0% +that uh it it's convenient to Define uh +another function where in many instances + + align:start position:0% +another function where in many instances + + + align:start position:0% +another function where in many instances +uh c not equals zero right when we're + + align:start position:0% +uh c not equals zero right when we're + + + align:start position:0% +uh c not equals zero right when we're +doping pure silicon the initial + + align:start position:0% +doping pure silicon the initial + + + align:start position:0% +doping pure silicon the initial +concentration of boron or phosphorus and + + align:start position:0% +concentration of boron or phosphorus and + + + align:start position:0% +concentration of boron or phosphorus and +pure silicon is going to be zero so for + + align:start position:0% +pure silicon is going to be zero so for + + + align:start position:0% +pure silicon is going to be zero so for +many of those so for many of those cases + + align:start position:0% +many of those so for many of those cases + + + align:start position:0% +many of those so for many of those cases +you'll end up with something that if you + + align:start position:0% +you'll end up with something that if you + + + align:start position:0% +you'll end up with something that if you +go through the math this is a zero + + align:start position:0% +go through the math this is a zero + + + align:start position:0% +go through the math this is a zero +transpose you'll end up with this as the + + align:start position:0% +transpose you'll end up with this as the + + + align:start position:0% +transpose you'll end up with this as the +solution Cal CS + + align:start position:0% +solution Cal CS + + + align:start position:0% +solution Cal CS +times the complimentary error function + + align:start position:0% +times the complimentary error function + + + align:start position:0% +times the complimentary error function +Earth complement X over two roots of DT + + align:start position:0% +Earth complement X over two roots of DT + + + align:start position:0% +Earth complement X over two roots of DT +where the complimentary error function + + align:start position:0% +where the complimentary error function + + + align:start position:0% +where the complimentary error function +Earth complement of Z is simply 1 minus + + align:start position:0% +Earth complement of Z is simply 1 minus + + + align:start position:0% +Earth complement of Z is simply 1 minus +Earth of Z so if you see that in the + + align:start position:0% +Earth of Z so if you see that in the + + + align:start position:0% +Earth of Z so if you see that in the +literature that's all they're all + + align:start position:0% +literature that's all they're all + + + align:start position:0% +literature that's all they're all +they're doing so now the question is + + align:start position:0% +they're doing so now the question is + + + align:start position:0% +they're doing so now the question is +I've told you that there's special + + align:start position:0% +I've told you that there's special + + + align:start position:0% +I've told you that there's special +conditions that validate the error + + align:start position:0% +conditions that validate the error + + + align:start position:0% +conditions that validate the error +function Solutions what are the + + align:start position:0% +function Solutions what are the + + + align:start position:0% +function Solutions what are the +conditions when when to use + + align:start position:0% +conditions when when to use + + + align:start position:0% +conditions when when to use +earth when to use Earth because that's + + align:start position:0% +earth when to use Earth because that's + + + align:start position:0% +earth when to use Earth because that's +not the only solution to fix second law + + align:start position:0% +not the only solution to fix second law + + + align:start position:0% +not the only solution to fix second law +when these are the conditions C of + + align:start position:0% +when these are the conditions C of + + + align:start position:0% +when these are the conditions C of +X at Time Zero is a constant so this is + + align:start position:0% +X at Time Zero is a constant so this is + + + align:start position:0% +X at Time Zero is a constant so this is +boundary condition number one boundary + + align:start position:0% +boundary condition number one boundary + + + align:start position:0% +boundary condition number one boundary +condition number one + + align:start position:0% +condition number one + + + align:start position:0% +condition number one +we threw away some time data so here's + + align:start position:0% +we threw away some time data so here's + + + align:start position:0% +we threw away some time data so here's +data at time equals zero the initial + + align:start position:0% +data at time equals zero the initial + + + align:start position:0% +data at time equals zero the initial +condition this is called the initial + + align:start position:0% +condition this is called the initial + + + align:start position:0% +condition this is called the initial +condition initial condition must be a + + align:start position:0% +condition initial condition must be a + + + align:start position:0% +condition initial condition must be a +constant and that's okay there are many + + align:start position:0% +constant and that's okay there are many + + + align:start position:0% +constant and that's okay there are many +systems for which the initial value of + + align:start position:0% +systems for which the initial value of + + + align:start position:0% +systems for which the initial value of +the material that's being diffused is + + align:start position:0% +the material that's being diffused is + + + align:start position:0% +the material that's being diffused is +constant throughout the material as + + align:start position:0% +constant throughout the material as + + + align:start position:0% +constant throughout the material as +opposed to bopping all over the place or + + align:start position:0% +opposed to bopping all over the place or + + + align:start position:0% +opposed to bopping all over the place or +maybe already having some kind of a + + align:start position:0% +maybe already having some kind of a + + + align:start position:0% +maybe already having some kind of a +gradient as long as you can make this + + align:start position:0% +gradient as long as you can make this + + + align:start position:0% +gradient as long as you can make this +assumption you're on the road now we + + align:start position:0% +assumption you're on the road now we + + + align:start position:0% +assumption you're on the road now we +need two more boundary conditions we + + align:start position:0% +need two more boundary conditions we + + + align:start position:0% +need two more boundary conditions we +need boundary conditions two and three + + align:start position:0% +need boundary conditions two and three + + + align:start position:0% +need boundary conditions two and three +over here because we got a double + + align:start position:0% +over here because we got a double + + + align:start position:0% +over here because we got a double +derivative right you got a some function + + align:start position:0% +derivative right you got a some function + + + align:start position:0% +derivative right you got a some function +plus constant when you do d by DX + + align:start position:0% +plus constant when you do d by DX + + + align:start position:0% +plus constant when you do d by DX +constant goes into the trash bin we need + + align:start position:0% +constant goes into the trash bin we need + + + align:start position:0% +constant goes into the trash bin we need +to recover that information somehow so + + align:start position:0% +to recover that information somehow so + + + align:start position:0% +to recover that information somehow so +here's what I've got I've got C for x + + align:start position:0% +here's what I've got I've got C for x + + + align:start position:0% +here's what I've got I've got C for x +equals z at all time is a constant the + + align:start position:0% +equals z at all time is a constant the + + + align:start position:0% +equals z at all time is a constant the +surface concentration is fixed as a + + align:start position:0% +surface concentration is fixed as a + + + align:start position:0% +surface concentration is fixed as a +constant okay and you say well well what + + align:start position:0% +constant okay and you say well well what + + + align:start position:0% +constant okay and you say well well what +else could it be well I could have a + + align:start position:0% +else could it be well I could have a + + + align:start position:0% +else could it be well I could have a +slowly Rising surface concentration or I + + align:start position:0% +slowly Rising surface concentration or I + + + align:start position:0% +slowly Rising surface concentration or I +could have a surface concentration that + + align:start position:0% +could have a surface concentration that + + + align:start position:0% +could have a surface concentration that +varies sinusoidally or something those + + align:start position:0% +varies sinusoidally or something those + + + align:start position:0% +varies sinusoidally or something those +won't work it must be fixed at a + + align:start position:0% +won't work it must be fixed at a + + + align:start position:0% +won't work it must be fixed at a +constant value so that's one so this is + + align:start position:0% +constant value so that's one so this is + + + align:start position:0% +constant value so that's one so this is +boundary condition this is boundary + + align:start position:0% +boundary condition this is boundary + + + align:start position:0% +boundary condition this is boundary +condition number one this is boundary + + align:start position:0% +condition number one this is boundary + + + align:start position:0% +condition number one this is boundary +condition boundary condition number two + + align:start position:0% +condition boundary condition number two + + + align:start position:0% +condition boundary condition number two +and then I've got I need a third one and + + align:start position:0% +and then I've got I need a third one and + + + align:start position:0% +and then I've got I need a third one and +the third one I'm going to get is this + + align:start position:0% +the third one I'm going to get is this + + + align:start position:0% +the third one I'm going to get is this +one I'm going to give you it looks funny + + align:start position:0% +one I'm going to give you it looks funny + + + align:start position:0% +one I'm going to give you it looks funny +when I write it mathematically but + + align:start position:0% +when I write it mathematically but + + + align:start position:0% +when I write it mathematically but +you'll you'll understand what I mean in + + align:start position:0% +you'll you'll understand what I mean in + + + align:start position:0% +you'll you'll understand what I mean in +a second uh at Infinity + + align:start position:0% +a second uh at Infinity + + + align:start position:0% +a second uh at Infinity +the concentration doesn't change you say + + align:start position:0% +the concentration doesn't change you say + + + align:start position:0% +the concentration doesn't change you say +well duh but this really has this really + + align:start position:0% +well duh but this really has this really + + + align:start position:0% +well duh but this really has this really +has some meaning we know that our we + + align:start position:0% +has some meaning we know that our we + + + align:start position:0% +has some meaning we know that our we +know that the size of our of our uh + + align:start position:0% +know that the size of our of our uh + + + align:start position:0% +know that the size of our of our uh +piece is not infinite but here's what + + align:start position:0% +piece is not infinite but here's what + + + align:start position:0% +piece is not infinite but here's what +we're assuming we're assuming that over + + align:start position:0% +we're assuming we're assuming that over + + + align:start position:0% +we're assuming we're assuming that over +the time scale of the process that for + + align:start position:0% +the time scale of the process that for + + + align:start position:0% +the time scale of the process that for +all intents and purposes the dimension + + align:start position:0% +all intents and purposes the dimension + + + align:start position:0% +all intents and purposes the dimension +of the Silicon wafer for example is so + + align:start position:0% +of the Silicon wafer for example is so + + + align:start position:0% +of the Silicon wafer for example is so +large in comparison to the depth of the + + align:start position:0% +large in comparison to the depth of the + + + align:start position:0% +large in comparison to the depth of the +diffusion profile file that assuming + + align:start position:0% +diffusion profile file that assuming + + + align:start position:0% +diffusion profile file that assuming +assuming that the wafer is semi infinite + + align:start position:0% +assuming that the wafer is semi infinite + + + align:start position:0% +assuming that the wafer is semi infinite +because we've got to diffusing in from + + align:start position:0% +because we've got to diffusing in from + + + align:start position:0% +because we've got to diffusing in from +both sides all right but let's just + + align:start position:0% +both sides all right but let's just + + + align:start position:0% +both sides all right but let's just +assume from the one side that we can + + align:start position:0% +assume from the one side that we can + + + align:start position:0% +assume from the one side that we can +assume that it's infinite because + + align:start position:0% +assume that it's infinite because + + + align:start position:0% +assume that it's infinite because +ultimately what happens if we wait long + + align:start position:0% +ultimately what happens if we wait long + + + align:start position:0% +ultimately what happens if we wait long +enough we start to have a tail over here + + align:start position:0% +enough we start to have a tail over here + + + align:start position:0% +enough we start to have a tail over here +because the system still thinks that the + + align:start position:0% +because the system still thinks that the + + + align:start position:0% +because the system still thinks that the +wafer exists but we're saying no it it + + align:start position:0% +wafer exists but we're saying no it it + + + align:start position:0% +wafer exists but we're saying no it it +stops here but this value is so small + + align:start position:0% +stops here but this value is so small + + + align:start position:0% +stops here but this value is so small +during the time scale of the uh process + + align:start position:0% +during the time scale of the uh process + + + align:start position:0% +during the time scale of the uh process +that we can neglect it and by allowing + + align:start position:0% +that we can neglect it and by allowing + + + align:start position:0% +that we can neglect it and by allowing +ourselves to assume that the material is + + align:start position:0% +ourselves to assume that the material is + + + align:start position:0% +ourselves to assume that the material is +semi-infinite it simplifies the math if + + align:start position:0% +semi-infinite it simplifies the math if + + + align:start position:0% +semi-infinite it simplifies the math if +we have a finite sized piece a finite + + align:start position:0% +we have a finite sized piece a finite + + + align:start position:0% +we have a finite sized piece a finite +size specimen we can't use this + + align:start position:0% +size specimen we can't use this + + + align:start position:0% +size specimen we can't use this +simplified solution and things get very + + align:start position:0% +simplified solution and things get very + + + align:start position:0% +simplified solution and things get very +very messy but there's another way of + + align:start position:0% +very messy but there's another way of + + + align:start position:0% +very messy but there's another way of +expressing it there's another way of + + align:start position:0% +expressing it there's another way of + + + align:start position:0% +expressing it there's another way of +expressing it you see this relationship + + align:start position:0% +expressing it you see this relationship + + + align:start position:0% +expressing it you see this relationship +it's always Earth X over 2 * the < TK of + + align:start position:0% +it's always Earth X over 2 * the < TK of + + + align:start position:0% +it's always Earth X over 2 * the < TK of +DT look it something would be infinite + + align:start position:0% +DT look it something would be infinite + + + align:start position:0% +DT look it something would be infinite +would mean it was it's very large + + align:start position:0% + + + + align:start position:0% + +large Dimension let's say large length + + align:start position:0% +large Dimension let's say large length + + + align:start position:0% +large Dimension let's say large length +scale large length + + align:start position:0% +scale large length + + + align:start position:0% +scale large length +scale that's a large physical Dimension + + align:start position:0% +scale that's a large physical Dimension + + + align:start position:0% +scale that's a large physical Dimension +so that means the argument of this is + + align:start position:0% +so that means the argument of this is + + + align:start position:0% +so that means the argument of this is +very very large but there's another way + + align:start position:0% +very very large but there's another way + + + align:start position:0% +very very large but there's another way +to get the same + + align:start position:0% +to get the same + + + align:start position:0% +to get the same +result short time + + align:start position:0% + + + + align:start position:0% + +scale so that means that every diffusion + + align:start position:0% +scale so that means that every diffusion + + + align:start position:0% +scale so that means that every diffusion +experiment + + align:start position:0% +experiment + + + align:start position:0% +experiment +initially is operating in a material + + align:start position:0% +initially is operating in a material + + + align:start position:0% +initially is operating in a material +that for all intents and purposes is + + align:start position:0% +that for all intents and purposes is + + + align:start position:0% +that for all intents and purposes is +infinite because when those first + + align:start position:0% +infinite because when those first + + + align:start position:0% +infinite because when those first +phosphorus atoms start diffusing into + + align:start position:0% +phosphorus atoms start diffusing into + + + align:start position:0% +phosphorus atoms start diffusing into +the Silicon they don't know the Silicon + + align:start position:0% +the Silicon they don't know the Silicon + + + align:start position:0% +the Silicon they don't know the Silicon +is only a millimeter thick as far as + + align:start position:0% +is only a millimeter thick as far as + + + align:start position:0% +is only a millimeter thick as far as +they're concerned it's infinitely thick + + align:start position:0% +they're concerned it's infinitely thick + + + align:start position:0% +they're concerned it's infinitely thick +so this solution is valid everywhere as + + align:start position:0% +so this solution is valid everywhere as + + + align:start position:0% +so this solution is valid everywhere as +long as you've got concentration initial + + align:start position:0% +long as you've got concentration initial + + + align:start position:0% +long as you've got concentration initial +fixed concentration surface fixed at + + align:start position:0% +fixed concentration surface fixed at + + + align:start position:0% +fixed concentration surface fixed at +Short times at Short times this solution + + align:start position:0% +Short times at Short times this solution + + + align:start position:0% +Short times at Short times this solution +is valid valid over at a short time so + + align:start position:0% +is valid valid over at a short time so + + + align:start position:0% +is valid valid over at a short time so +that means it's got great utility + + align:start position:0% +that means it's got great utility + + + align:start position:0% +that means it's got great utility +great utility and now I want to show you + + align:start position:0% +great utility and now I want to show you + + + align:start position:0% +great utility and now I want to show you +something that takes everything we've + + align:start position:0% +something that takes everything we've + + + align:start position:0% +something that takes everything we've +learned and crashes it into a simple + + align:start position:0% +learned and crashes it into a simple + + + align:start position:0% +learned and crashes it into a simple +rule of thumb rule of thumb and these + + align:start position:0% +rule of thumb rule of thumb and these + + + align:start position:0% +rule of thumb rule of thumb and these +are the kinds of of rules that I hope + + align:start position:0% +are the kinds of of rules that I hope + + + align:start position:0% +are the kinds of of rules that I hope +you'll retain long after what was it + + align:start position:0% +you'll retain long after what was it + + + align:start position:0% +you'll retain long after what was it +Franklin said education is what remains + + align:start position:0% +Franklin said education is what remains + + + align:start position:0% +Franklin said education is what remains +when you've forgotten all of your + + align:start position:0% +when you've forgotten all of your + + + align:start position:0% +when you've forgotten all of your +schooling so this is what you'll + + align:start position:0% +schooling so this is what you'll + + + align:start position:0% +schooling so this is what you'll +remember um you see you've got C minus + + align:start position:0% +remember um you see you've got C minus + + + align:start position:0% +remember um you see you've got C minus +CS over C minus Cs and that's equal to + + align:start position:0% +CS over C minus Cs and that's equal to + + + align:start position:0% +CS over C minus Cs and that's equal to +over here Earth X over 2 roots of DT + + align:start position:0% +over here Earth X over 2 roots of DT + + + align:start position:0% +over here Earth X over 2 roots of DT +that's the accurate solution so if I + + align:start position:0% +that's the accurate solution so if I + + + align:start position:0% +that's the accurate solution so if I +wanted to capture the whole defusion + + align:start position:0% +wanted to capture the whole defusion + + + align:start position:0% +wanted to capture the whole defusion +process in one tiny little + + align:start position:0% +process in one tiny little + + + align:start position:0% +process in one tiny little +sentence what would be an average value + + align:start position:0% +sentence what would be an average value + + + align:start position:0% +sentence what would be an average value +this is a normalized ratio isn't it it + + align:start position:0% +this is a normalized ratio isn't it it + + + align:start position:0% +this is a normalized ratio isn't it it +goes from 0 to one so what's an average + + align:start position:0% +goes from 0 to one so what's an average + + + align:start position:0% +goes from 0 to one so what's an average +value between zero and one I don't know + + align:start position:0% +value between zero and one I don't know + + + align:start position:0% +value between zero and one I don't know +how about a half so suppose I just + + align:start position:0% +how about a half so suppose I just + + + align:start position:0% +how about a half so suppose I just +choose this as an average value for the + + align:start position:0% +choose this as an average value for the + + + align:start position:0% +choose this as an average value for the +whole diffusion process everything that + + align:start position:0% +whole diffusion process everything that + + + align:start position:0% +whole diffusion process everything that +can ever happen in + + align:start position:0% +can ever happen in + + + align:start position:0% +can ever happen in +Fusion well a half is less than 6 since + + align:start position:0% +Fusion well a half is less than 6 since + + + align:start position:0% +Fusion well a half is less than 6 since +a half is less than 6 I can approximate + + align:start position:0% +a half is less than 6 I can approximate + + + align:start position:0% +a half is less than 6 I can approximate +Earth X over 2 roots of DT is simply X + + align:start position:0% +Earth X over 2 roots of DT is simply X + + + align:start position:0% +Earth X over 2 roots of DT is simply X +over 2 roots of DT so now I've got this + + align:start position:0% +over 2 roots of DT so now I've got this + + + align:start position:0% +over 2 roots of DT so now I've got this +equals this so I'll cancel out the twos + + align:start position:0% +equals this so I'll cancel out the twos + + + align:start position:0% +equals this so I'll cancel out the twos +and I cross multiply and then that gives + + align:start position:0% +and I cross multiply and then that gives + + + align:start position:0% +and I cross multiply and then that gives +me X goes as two roots of DT as an + + align:start position:0% +me X goes as two roots of DT as an + + + align:start position:0% +me X goes as two roots of DT as an +overarching equation for everything that + + align:start position:0% +overarching equation for everything that + + + align:start position:0% +overarching equation for everything that +happens in short-term + + align:start position:0% +happens in short-term + + + align:start position:0% +happens in short-term +diffusion short-term diffusion I can't + + align:start position:0% +diffusion short-term diffusion I can't + + + align:start position:0% +diffusion short-term diffusion I can't +tell you how many times I've been in + + align:start position:0% +tell you how many times I've been in + + + align:start position:0% +tell you how many times I've been in +situations where I'm in some conference + + align:start position:0% +situations where I'm in some conference + + + align:start position:0% +situations where I'm in some conference +room and a bunch of people are sitting + + align:start position:0% +room and a bunch of people are sitting + + + align:start position:0% +room and a bunch of people are sitting +around trying to figure out what to do + + align:start position:0% +around trying to figure out what to do + + + align:start position:0% +around trying to figure out what to do +and somebody's getting ready to do some + + align:start position:0% +and somebody's getting ready to do some + + + align:start position:0% +and somebody's getting ready to do some +you know finite element calculation to + + align:start position:0% +you know finite element calculation to + + + align:start position:0% +you know finite element calculation to +go mathematically model this whole + + align:start position:0% +go mathematically model this whole + + + align:start position:0% +go mathematically model this whole +process and I sit back and I go gee well + + align:start position:0% +process and I sit back and I go gee well + + + align:start position:0% +process and I sit back and I go gee well +I know the length scales it's on the + + align:start position:0% +I know the length scales it's on the + + + align:start position:0% +I know the length scales it's on the +order of um well why don't we do one why + + align:start position:0% +order of um well why don't we do one why + + + align:start position:0% +order of um well why don't we do one why +don't we do one let's do one let's put + + align:start position:0% +don't we do one let's do one let's put + + + align:start position:0% +don't we do one let's do one let's put +the let's put the rest that myth have + + align:start position:0% +the let's put the rest that myth have + + + align:start position:0% +the let's put the rest that myth have +you ever been told told this thing about + + align:start position:0% +you ever been told told this thing about + + + align:start position:0% +you ever been told told this thing about +Cathedral Windows why the glass at the + + align:start position:0% +Cathedral Windows why the glass at the + + + align:start position:0% +Cathedral Windows why the glass at the +bottom of a cathedral window is is + + align:start position:0% +bottom of a cathedral window is is + + + align:start position:0% +bottom of a cathedral window is is +thicker than it is at the top and it has + + align:start position:0% +thicker than it is at the top and it has + + + align:start position:0% +thicker than it is at the top and it has +to do with the fact that glass is is + + align:start position:0% +to do with the fact that glass is is + + + align:start position:0% +to do with the fact that glass is is +really a viscous liquid and and over 500 + + align:start position:0% +really a viscous liquid and and over 500 + + + align:start position:0% +really a viscous liquid and and over 500 +years it it it trickles and it gets + + align:start position:0% +years it it it trickles and it gets + + + align:start position:0% +years it it it trickles and it gets +wider it's nuts it's nuts and I can show + + align:start position:0% +wider it's nuts it's nuts and I can show + + + align:start position:0% +wider it's nuts it's nuts and I can show +you like this it's very simple you + + align:start position:0% +you like this it's very simple you + + + align:start position:0% +you like this it's very simple you +already know that you know the average + + align:start position:0% +already know that you know the average + + + align:start position:0% +already know that you know the average +what's the average temperature in a + + align:start position:0% +what's the average temperature in a + + + align:start position:0% +what's the average temperature in a +cathedral in northern Europe it's zero + + align:start position:0% +cathedral in northern Europe it's zero + + + align:start position:0% +cathedral in northern Europe it's zero +in the winter it's 20° in the summer + + align:start position:0% +in the winter it's 20° in the summer + + + align:start position:0% +in the winter it's 20° in the summer +let's pick a number 10° C all right so + + align:start position:0% +let's pick a number 10° C all right so + + + align:start position:0% +let's pick a number 10° C all right so +10° C what do you think the diffusion + + align:start position:0% +10° C what do you think the diffusion + + + align:start position:0% +10° C what do you think the diffusion +coefficient of silicate glass at 10° C + + align:start position:0% +coefficient of silicate glass at 10° C + + + align:start position:0% +coefficient of silicate glass at 10° C +would have to be for this thing to go + + align:start position:0% +would have to be for this thing to go + + + align:start position:0% +would have to be for this thing to go +anywhere so here's what I did I said all + + align:start position:0% +anywhere so here's what I did I said all + + + align:start position:0% +anywhere so here's what I did I said all +right well let's use this so here's my + + align:start position:0% +right well let's use this so here's my + + + align:start position:0% +right well let's use this so here's my +simple model of a of the cathedral + + align:start position:0% +simple model of a of the cathedral + + + align:start position:0% +simple model of a of the cathedral +window and this is the crosssection okay + + align:start position:0% +window and this is the crosssection okay + + + align:start position:0% +window and this is the crosssection okay +and and I figure I need a length scale + + align:start position:0% +and and I figure I need a length scale + + + align:start position:0% +and and I figure I need a length scale +so I chose a length scale if something's + + align:start position:0% +so I chose a length scale if something's + + + align:start position:0% +so I chose a length scale if something's +going to diffuse on the order of I don't + + align:start position:0% +going to diffuse on the order of I don't + + + align:start position:0% +going to diffuse on the order of I don't +know 10 cm you can quibble if you want + + align:start position:0% +know 10 cm you can quibble if you want + + + align:start position:0% +know 10 cm you can quibble if you want +to make it 1 cm I don't care I'm going + + align:start position:0% +to make it 1 cm I don't care I'm going + + + align:start position:0% +to make it 1 cm I don't care I'm going +to blow this thing so far out of the + + align:start position:0% +to blow this thing so far out of the + + + align:start position:0% +to blow this thing so far out of the +water it won't matter won't matter all + + align:start position:0% +water it won't matter won't matter all + + + align:start position:0% +water it won't matter won't matter all +right so this is about 10 cm right and + + align:start position:0% +right so this is about 10 cm right and + + + align:start position:0% +right so this is about 10 cm right and +it's going to get thicker on the bottom + + align:start position:0% +it's going to get thicker on the bottom + + + align:start position:0% +it's going to get thicker on the bottom +and and and I figure I'm going to give + + align:start position:0% +and and and I figure I'm going to give + + + align:start position:0% +and and and I figure I'm going to give +this a really long run time so I'm going + + align:start position:0% +this a really long run time so I'm going + + + align:start position:0% +this a really long run time so I'm going +to make it 500 years 500 years and what + + align:start position:0% +to make it 500 years 500 years and what + + + align:start position:0% +to make it 500 years 500 years and what +I'm going to do I want to show you how + + align:start position:0% +I'm going to do I want to show you how + + + align:start position:0% +I'm going to do I want to show you how +to put this problem to the test what I'm + + align:start position:0% +to put this problem to the test what I'm + + + align:start position:0% +to put this problem to the test what I'm +going to do is I'm going to derive a + + align:start position:0% +going to do is I'm going to derive a + + + align:start position:0% +going to do is I'm going to derive a +quantity that I can say yes or no to so + + align:start position:0% +quantity that I can say yes or no to so + + + align:start position:0% +quantity that I can say yes or no to so +what I'm going to try to do is pull out + + align:start position:0% +what I'm going to try to do is pull out + + + align:start position:0% +what I'm going to try to do is pull out +a value of the diffusion coefficient so + + align:start position:0% +a value of the diffusion coefficient so + + + align:start position:0% +a value of the diffusion coefficient so +I know that X x^2 = DT if I just Square + + align:start position:0% +I know that X x^2 = DT if I just Square + + + align:start position:0% +I know that X x^2 = DT if I just Square +both sides of that thing so that means + + align:start position:0% +both sides of that thing so that means + + + align:start position:0% +both sides of that thing so that means +that D the diffusion coefficient should + + align:start position:0% +that D the diffusion coefficient should + + + align:start position:0% +that D the diffusion coefficient should +be x^2 divided + + align:start position:0% +be x^2 divided + + + align:start position:0% +be x^2 divided +T so I'm going to I'm going to do this + + align:start position:0% +T so I'm going to I'm going to do this + + + align:start position:0% +T so I'm going to I'm going to do this +in in C uh centimeters so this is 10 squ + + align:start position:0% +in in C uh centimeters so this is 10 squ + + + align:start position:0% +in in C uh centimeters so this is 10 squ +on the top and time is 500 years so + + align:start position:0% +on the top and time is 500 years so + + + align:start position:0% +on the top and time is 500 years so +that's 500 and how many seconds in a + + align:start position:0% +that's 500 and how many seconds in a + + + align:start position:0% +that's 500 and how many seconds in a +year + + align:start position:0% +year + + + align:start position:0% +year +quick Pi * 10 to the + + align:start position:0% + + + + align:start position:0% + +7th pi times 10 million is good to + + align:start position:0% +7th pi times 10 million is good to + + + align:start position:0% +7th pi times 10 million is good to +within about a percent + + align:start position:0% +within about a percent + + + align:start position:0% +within about a percent +okay so that's it I mean who cares we're + + align:start position:0% +okay so that's it I mean who cares we're + + + align:start position:0% +okay so that's it I mean who cares we're +this is a diffusion calculation you + + align:start position:0% +this is a diffusion calculation you + + + align:start position:0% +this is a diffusion calculation you +don't need it anymore you're not going + + align:start position:0% +don't need it anymore you're not going + + + align:start position:0% +don't need it anymore you're not going +to go the 365 days how many leap years + + align:start position:0% +to go the 365 days how many leap years + + + align:start position:0% +to go the 365 days how many leap years +were there and there come on get with it + + align:start position:0% +were there and there come on get with it + + + align:start position:0% +were there and there come on get with it +all right so + + align:start position:0% +all right so + + + align:start position:0% +all right so +6.4 time 10 to- 9 cm squar per second + + align:start position:0% +6.4 time 10 to- 9 cm squar per second + + + align:start position:0% +6.4 time 10 to- 9 cm squar per second +I'd need a diffusion coefficient of a + + align:start position:0% +I'd need a diffusion coefficient of a + + + align:start position:0% +I'd need a diffusion coefficient of a +silicate glass of 10 Theus n i mean + + align:start position:0% +silicate glass of 10 Theus n i mean + + + align:start position:0% +silicate glass of 10 Theus n i mean +that's the diffusion coefficient of a + + align:start position:0% +that's the diffusion coefficient of a + + + align:start position:0% +that's the diffusion coefficient of a +close- packed metal at its melting point + + align:start position:0% +close- packed metal at its melting point + + + align:start position:0% +close- packed metal at its melting point +so I went I looked up some data and + + align:start position:0% +so I went I looked up some data and + + + align:start position:0% +so I went I looked up some data and +here's what I found for the diffusion + + align:start position:0% +here's what I found for the diffusion + + + align:start position:0% +here's what I found for the diffusion +coefficient of sodium in a soda lime + + align:start position:0% +coefficient of sodium in a soda lime + + + align:start position:0% +coefficient of sodium in a soda lime +glass such as the type that would be + + align:start position:0% +glass such as the type that would be + + + align:start position:0% +glass such as the type that would be +used in those + + align:start position:0% +used in those + + + align:start position:0% +used in those +windows and using those data at 10° C + + align:start position:0% +windows and using those data at 10° C + + + align:start position:0% +windows and using those data at 10° C +the diffusion coefficient would be + + align:start position:0% +the diffusion coefficient would be + + + align:start position:0% +the diffusion coefficient would be +10-19 cm squar per second it's off by a + + align:start position:0% +10-19 cm squar per second it's off by a + + + align:start position:0% +10-19 cm squar per second it's off by a +mere 10 orders of magnitude so I don't + + align:start position:0% +mere 10 orders of magnitude so I don't + + + align:start position:0% +mere 10 orders of magnitude so I don't +care if you want to make this 1 cmet if + + align:start position:0% +care if you want to make this 1 cmet if + + + align:start position:0% +care if you want to make this 1 cmet if +you want to make it 1 millimeter there's + + align:start position:0% +you want to make it 1 millimeter there's + + + align:start position:0% +you want to make it 1 millimeter there's +no way there's no way that's the X + + align:start position:0% +no way there's no way that's the X + + + align:start position:0% +no way there's no way that's the X +explanation we know what the reason is I + + align:start position:0% +explanation we know what the reason is I + + + align:start position:0% +explanation we know what the reason is I +mean this proves that it can't be I what + + align:start position:0% +mean this proves that it can't be I what + + + align:start position:0% +mean this proves that it can't be I what +I want to show you is that you can come + + align:start position:0% +I want to show you is that you can come + + + align:start position:0% +I want to show you is that you can come +at it from both sides you know the other + + align:start position:0% +at it from both sides you know the other + + + align:start position:0% +at it from both sides you know the other +thing is to figure out how do they make + + align:start position:0% +thing is to figure out how do they make + + + align:start position:0% +thing is to figure out how do they make +the glass you know how they made the + + align:start position:0% +the glass you know how they made the + + + align:start position:0% +the glass you know how they made the +glass they pull it out of a layer and + + align:start position:0% +glass they pull it out of a layer and + + + align:start position:0% +glass they pull it out of a layer and +they put it on a spinning + + align:start position:0% +they put it on a spinning + + + align:start position:0% +they put it on a spinning +table that's how they could flatten it + + align:start position:0% +table that's how they could flatten it + + + align:start position:0% +table that's how they could flatten it +they didn't have the float glass process + + align:start position:0% +they didn't have the float glass process + + + align:start position:0% +they didn't have the float glass process +where you pour silicate on top of liquid + + align:start position:0% +where you pour silicate on top of liquid + + + align:start position:0% +where you pour silicate on top of liquid +tin and liquid tin has a perfectly flat + + align:start position:0% +tin and liquid tin has a perfectly flat + + + align:start position:0% +tin and liquid tin has a perfectly flat +surface and the silicate glass is less + + align:start position:0% +surface and the silicate glass is less + + + align:start position:0% +surface and the silicate glass is less +dense and it's insoluble and so it + + align:start position:0% +dense and it's insoluble and so it + + + align:start position:0% +dense and it's insoluble and so it +floats on the liquid tin surface and is + + align:start position:0% +floats on the liquid tin surface and is + + + align:start position:0% +floats on the liquid tin surface and is +perfectly flat they didn't do that back + + align:start position:0% +perfectly flat they didn't do that back + + + align:start position:0% +perfectly flat they didn't do that back +in medieval times they spun they they + + align:start position:0% +in medieval times they spun they they + + + align:start position:0% +in medieval times they spun they they +they they spun cast it it was like a + + align:start position:0% +they they spun cast it it was like a + + + align:start position:0% +they they spun cast it it was like a +spin coating technique so you got some + + align:start position:0% +spin coating technique so you got some + + + align:start position:0% +spin coating technique so you got some +table spinning this is top view some + + align:start position:0% +table spinning this is top view some + + + align:start position:0% +table spinning this is top view some +table spinning and you plop some glass + + align:start position:0% +table spinning and you plop some glass + + + align:start position:0% +table spinning and you plop some glass +on it goes by centrifugal force right so + + align:start position:0% +on it goes by centrifugal force right so + + + align:start position:0% +on it goes by centrifugal force right so +now the cross-section of the glass + + align:start position:0% +now the cross-section of the glass + + + align:start position:0% +now the cross-section of the glass +what's it look like well let's start + + align:start position:0% +what's it look like well let's start + + + align:start position:0% +what's it look like well let's start +from the center and go out guess what + + align:start position:0% +from the center and go out guess what + + + align:start position:0% +from the center and go out guess what +not to scale it's ever so slightly + + align:start position:0% +not to scale it's ever so slightly + + + align:start position:0% +not to scale it's ever so slightly +thicker on the outside than the inside + + align:start position:0% +thicker on the outside than the inside + + + align:start position:0% +thicker on the outside than the inside +and people would actually be very + + align:start position:0% +and people would actually be very + + + align:start position:0% +and people would actually be very +careful about choosing the pieces and + + align:start position:0% +careful about choosing the pieces and + + + align:start position:0% +careful about choosing the pieces and +then the glazers said when you mount the + + align:start position:0% +then the glazers said when you mount the + + + align:start position:0% +then the glazers said when you mount the +windows let's put all the glass in with + + align:start position:0% +windows let's put all the glass in with + + + align:start position:0% +windows let's put all the glass in with +the thick side down wouldn't that make + + align:start position:0% +the thick side down wouldn't that make + + + align:start position:0% +the thick side down wouldn't that make +sense and that's why the glass is + + align:start position:0% +sense and that's why the glass is + + + align:start position:0% +sense and that's why the glass is +thicker because it was made that + + align:start position:0% +thicker because it was made that + + + align:start position:0% +thicker because it was made that +way simple answer but you can do the + + align:start position:0% +way simple answer but you can do the + + + align:start position:0% +way simple answer but you can do the +calculation I don't know how many times + + align:start position:0% +calculation I don't know how many times + + + align:start position:0% +calculation I don't know how many times +I get I get this asked this at least + + align:start position:0% +I get I get this asked this at least + + + align:start position:0% +I get I get this asked this at least +once a year someone says is it true that + + align:start position:0% +once a year someone says is it true that + + + align:start position:0% +once a year someone says is it true that +the cathedrals and I go okay does this + + align:start position:0% +the cathedrals and I go okay does this + + + align:start position:0% +the cathedrals and I go okay does this +person know fixed law or not don't know + + align:start position:0% +person know fixed law or not don't know + + + align:start position:0% +person know fixed law or not don't know +okay so we have to give a different + + align:start position:0% +okay so we have to give a different + + + align:start position:0% +okay so we have to give a different +explanation all right so um good now I + + align:start position:0% +explanation all right so um good now I + + + align:start position:0% +explanation all right so um good now I +want to finish the story of the uh + + align:start position:0% +want to finish the story of the uh + + + align:start position:0% +want to finish the story of the uh +automobile uh exhaust catalyst and show + + align:start position:0% +automobile uh exhaust catalyst and show + + + align:start position:0% +automobile uh exhaust catalyst and show +how we can bring a lot of what we've + + align:start position:0% +how we can bring a lot of what we've + + + align:start position:0% +how we can bring a lot of what we've +been learning the last several days + + align:start position:0% +been learning the last several days + + + align:start position:0% +been learning the last several days +together so just to review uh this is an + + align:start position:0% +together so just to review uh this is an + + + align:start position:0% +together so just to review uh this is an +old sketch because it was taken from an + + align:start position:0% +old sketch because it was taken from an + + + align:start position:0% +old sketch because it was taken from an +early General Motors publication + + align:start position:0% +early General Motors publication + + + align:start position:0% +early General Motors publication +from the 80s but uh basically what + + align:start position:0% +from the 80s but uh basically what + + + align:start position:0% +from the 80s but uh basically what +you've got is we've seen the catalytic + + align:start position:0% +you've got is we've seen the catalytic + + + align:start position:0% +you've got is we've seen the catalytic +converter and it's taking the the + + align:start position:0% +converter and it's taking the the + + + align:start position:0% +converter and it's taking the the +exhaust gases and trying to convert some + + align:start position:0% +exhaust gases and trying to convert some + + + align:start position:0% +exhaust gases and trying to convert some +of the toxins into something less + + align:start position:0% +of the toxins into something less + + + align:start position:0% +of the toxins into something less +offensive um and and i' reported to you + + align:start position:0% +offensive um and and i' reported to you + + + align:start position:0% +offensive um and and i' reported to you +that we need to control in order to + + align:start position:0% +that we need to control in order to + + + align:start position:0% +that we need to control in order to +achieve both oxidation and reduction and + + align:start position:0% +achieve both oxidation and reduction and + + + align:start position:0% +achieve both oxidation and reduction and +how do we control we control with the + + align:start position:0% +how do we control we control with the + + + align:start position:0% +how do we control we control with the +aid of an oxygen sensor and Matt could + + align:start position:0% +aid of an oxygen sensor and Matt could + + + align:start position:0% +aid of an oxygen sensor and Matt could +we switch to the um document camera + + align:start position:0% +we switch to the um document camera + + + align:start position:0% +we switch to the um document camera +please for a second + + align:start position:0% +please for a second + + + align:start position:0% +please for a second +take that input so what I'm showing you + + align:start position:0% +take that input so what I'm showing you + + + align:start position:0% +take that input so what I'm showing you +is an oxygen sensor uh this is + + align:start position:0% + + + + align:start position:0% + +a good and + + align:start position:0% + + + + align:start position:0% + +autofocus good all right so what you're + + align:start position:0% +autofocus good all right so what you're + + + align:start position:0% +autofocus good all right so what you're +looking at is this is the metal uh + + align:start position:0% +looking at is this is the metal uh + + + align:start position:0% +looking at is this is the metal uh +sleeve on top of the oxygen sensor and + + align:start position:0% +sleeve on top of the oxygen sensor and + + + align:start position:0% +sleeve on top of the oxygen sensor and +you can see veins here and this is + + align:start position:0% +you can see veins here and this is + + + align:start position:0% +you can see veins here and this is +inserted uh just past the engine before + + align:start position:0% +inserted uh just past the engine before + + + align:start position:0% +inserted uh just past the engine before +the catalytic converter and what I want + + align:start position:0% +the catalytic converter and what I want + + + align:start position:0% +the catalytic converter and what I want +want to do is to describe the solid + + align:start position:0% +want to do is to describe the solid + + + align:start position:0% +want to do is to describe the solid +state chemistry that's going on inside + + align:start position:0% +state chemistry that's going on inside + + + align:start position:0% +state chemistry that's going on inside +there so Matt may we go back to the + + align:start position:0% +there so Matt may we go back to the + + + align:start position:0% +there so Matt may we go back to the +computer + + align:start position:0% + + + + align:start position:0% + +please thank you okay so that what I + + align:start position:0% +please thank you okay so that what I + + + align:start position:0% +please thank you okay so that what I +just showed you is sitting right here + + align:start position:0% +just showed you is sitting right here + + + align:start position:0% +just showed you is sitting right here +just as the exhaust gases leave the + + align:start position:0% +just as the exhaust gases leave the + + + align:start position:0% +just as the exhaust gases leave the +engine and what they're doing is they're + + align:start position:0% +engine and what they're doing is they're + + + align:start position:0% +engine and what they're doing is they're +measuring the oxygen pressure in the + + align:start position:0% +measuring the oxygen pressure in the + + + align:start position:0% +measuring the oxygen pressure in the +exhaust gases so that we can control the + + align:start position:0% +exhaust gases so that we can control the + + + align:start position:0% +exhaust gases so that we can control the +air to fuel ratio because it turns out + + align:start position:0% +air to fuel ratio because it turns out + + + align:start position:0% +air to fuel ratio because it turns out +that to convert the co and the + + align:start position:0% +that to convert the co and the + + + align:start position:0% +that to convert the co and the +hydrocarbons to the desired products in + + align:start position:0% +hydrocarbons to the desired products in + + + align:start position:0% +hydrocarbons to the desired products in +other words carbon dioxide water vapor + + align:start position:0% +other words carbon dioxide water vapor + + + align:start position:0% +other words carbon dioxide water vapor +and carbon dioxide you need to oxidize + + align:start position:0% +and carbon dioxide you need to oxidize + + + align:start position:0% +and carbon dioxide you need to oxidize +and the catalyst is pretty good at very + + align:start position:0% +and the catalyst is pretty good at very + + + align:start position:0% +and the catalyst is pretty good at very +very high air ratios and to reduce nox + + align:start position:0% +very high air ratios and to reduce nox + + + align:start position:0% +very high air ratios and to reduce nox +to nitrogen you need to have Rich fuel + + align:start position:0% +to nitrogen you need to have Rich fuel + + + align:start position:0% +to nitrogen you need to have Rich fuel +ratios and mercifully nature was kind + + align:start position:0% +ratios and mercifully nature was kind + + + align:start position:0% +ratios and mercifully nature was kind +and there's this tiny window at about + + align:start position:0% +and there's this tiny window at about + + + align:start position:0% +and there's this tiny window at about +14.6 to1 where you get fairly high + + align:start position:0% +14.6 to1 where you get fairly high + + + align:start position:0% +14.6 to1 where you get fairly high +yields on both catalytic reactions so + + align:start position:0% +yields on both catalytic reactions so + + + align:start position:0% +yields on both catalytic reactions so +this is where you want to Park yourself + + align:start position:0% +this is where you want to Park yourself + + + align:start position:0% +this is where you want to Park yourself +but you so now you need to have a sensor + + align:start position:0% +but you so now you need to have a sensor + + + align:start position:0% +but you so now you need to have a sensor +and that sensor looks like this it is + + align:start position:0% +and that sensor looks like this it is + + + align:start position:0% +and that sensor looks like this it is +zironia it's an ionic oxide and it's + + align:start position:0% +zironia it's an ionic oxide and it's + + + align:start position:0% +zironia it's an ionic oxide and it's +doped with calcium oxide to create + + align:start position:0% +doped with calcium oxide to create + + + align:start position:0% +doped with calcium oxide to create +oxygen vacancies so we're going to get + + align:start position:0% +oxygen vacancies so we're going to get + + + align:start position:0% +oxygen vacancies so we're going to get +defects involved and we're going to talk + + align:start position:0% +defects involved and we're going to talk + + + align:start position:0% +defects involved and we're going to talk +about diffusion when we put calcium + + align:start position:0% +about diffusion when we put calcium + + + align:start position:0% +about diffusion when we put calcium +oxide into zironia we have two plus C on + + align:start position:0% +oxide into zironia we have two plus C on + + + align:start position:0% +oxide into zironia we have two plus C on +a four plus site and so we need to make + + align:start position:0% +a four plus site and so we need to make + + + align:start position:0% +a four plus site and so we need to make +an oxygen vacancy to compensate so as we + + align:start position:0% +an oxygen vacancy to compensate so as we + + + align:start position:0% +an oxygen vacancy to compensate so as we +add calcium oxide we make more oxygen + + align:start position:0% +add calcium oxide we make more oxygen + + + align:start position:0% +add calcium oxide we make more oxygen +vacancies which means that the diffusion + + align:start position:0% +vacancies which means that the diffusion + + + align:start position:0% +vacancies which means that the diffusion +coefficient goes up and that shortens + + align:start position:0% +coefficient goes up and that shortens + + + align:start position:0% +coefficient goes up and that shortens +the response time it's no good having a + + align:start position:0% +the response time it's no good having a + + + align:start position:0% +the response time it's no good having a +sensor that responds on a scale time + + align:start position:0% +sensor that responds on a scale time + + + align:start position:0% +sensor that responds on a scale time +scale of minutes when your driving + + align:start position:0% +scale of minutes when your driving + + + align:start position:0% +scale of minutes when your driving +conditions are changing on a time scale + + align:start position:0% +conditions are changing on a time scale + + + align:start position:0% +conditions are changing on a time scale +of seconds and so we dope with a + + align:start position:0% +of seconds and so we dope with a + + + align:start position:0% +of seconds and so we dope with a +subvalent oxide in order to improve the + + align:start position:0% +subvalent oxide in order to improve the + + + align:start position:0% +subvalent oxide in order to improve the +performance and here's a a cartoon that + + align:start position:0% +performance and here's a a cartoon that + + + align:start position:0% +performance and here's a a cartoon that +uh shows this is what's underneath the + + align:start position:0% +uh shows this is what's underneath the + + + align:start position:0% +uh shows this is what's underneath the +vein this blue that I've drawn is a + + align:start position:0% +vein this blue that I've drawn is a + + + align:start position:0% +vein this blue that I've drawn is a +closed one-end zercon your tube there + + align:start position:0% +closed one-end zercon your tube there + + + align:start position:0% +closed one-end zercon your tube there +are electrodes on the inside and the uh + + align:start position:0% +are electrodes on the inside and the uh + + + align:start position:0% +are electrodes on the inside and the uh +on the inside this is the exhaust and on + + align:start position:0% +on the inside this is the exhaust and on + + + align:start position:0% +on the inside this is the exhaust and on +the outside it's open to the air and + + align:start position:0% +the outside it's open to the air and + + + align:start position:0% +the outside it's open to the air and +this measures a voltage across the + + align:start position:0% +this measures a voltage across the + + + align:start position:0% +this measures a voltage across the +zirconia sensor and that voltage goes to + + align:start position:0% +zirconia sensor and that voltage goes to + + + align:start position:0% +zirconia sensor and that voltage goes to +the CPU every car has several computers + + align:start position:0% +the CPU every car has several computers + + + align:start position:0% +the CPU every car has several computers +on it but the first cars to have + + align:start position:0% +on it but the first cars to have + + + align:start position:0% +on it but the first cars to have +computers had them in order to control + + align:start position:0% +computers had them in order to control + + + align:start position:0% +computers had them in order to control +air to fuel ratio to make the catalytic + + align:start position:0% +air to fuel ratio to make the catalytic + + + align:start position:0% +air to fuel ratio to make the catalytic +converter effective and then that goes + + align:start position:0% +converter effective and then that goes + + + align:start position:0% +converter effective and then that goes +to control either the carburetor or + + align:start position:0% +to control either the carburetor or + + + align:start position:0% +to control either the carburetor or +nowadays the uh fuel injectors which + + align:start position:0% +nowadays the uh fuel injectors which + + + align:start position:0% +nowadays the uh fuel injectors which +then keeps the fuel to air ratio so that + + align:start position:0% +then keeps the fuel to air ratio so that + + + align:start position:0% +then keeps the fuel to air ratio so that +this keeps measuring 14.6 to1 and if you + + align:start position:0% +this keeps measuring 14.6 to1 and if you + + + align:start position:0% +this keeps measuring 14.6 to1 and if you +change altitude if the if you get stuck + + align:start position:0% +change altitude if the if you get stuck + + + align:start position:0% +change altitude if the if you get stuck +in the Callahan tunnel and the ambient + + align:start position:0% +in the Callahan tunnel and the ambient + + + align:start position:0% +in the Callahan tunnel and the ambient +conditions are changing this can respond + + align:start position:0% +conditions are changing this can respond + + + align:start position:0% +conditions are changing this can respond +can respond to changes in temperature + + align:start position:0% +can respond to changes in temperature + + + align:start position:0% +can respond to changes in temperature +what do you think the uh partial + + align:start position:0% +what do you think the uh partial + + + align:start position:0% +what do you think the uh partial +pressure of oxygen is about 20% in air + + align:start position:0% +pressure of oxygen is about 20% in air + + + align:start position:0% +pressure of oxygen is about 20% in air +but how much oxygen per unit volume do + + align:start position:0% +but how much oxygen per unit volume do + + + align:start position:0% +but how much oxygen per unit volume do +you have at 100° Fahrenheit versus 0 + + align:start position:0% +you have at 100° Fahrenheit versus 0 + + + align:start position:0% +you have at 100° Fahrenheit versus 0 +degrees Fahrenheit this thing can figure + + align:start position:0% +degrees Fahrenheit this thing can figure + + + align:start position:0% +degrees Fahrenheit this thing can figure +all that out and thereby run the system + + align:start position:0% +all that out and thereby run the system + + + align:start position:0% +all that out and thereby run the system +at the optimum fuel to aair ratio to + + align:start position:0% +at the optimum fuel to aair ratio to + + + align:start position:0% +at the optimum fuel to aair ratio to +maximally get the output from the + + align:start position:0% +maximally get the output from the + + + align:start position:0% +maximally get the output from the +catalytic converter and so in 3091 we've + + align:start position:0% +catalytic converter and so in 3091 we've + + + align:start position:0% +catalytic converter and so in 3091 we've +learned about the doping of silicon to + + align:start position:0% +learned about the doping of silicon to + + + align:start position:0% +learned about the doping of silicon to +make what goes into here we've learned + + align:start position:0% +make what goes into here we've learned + + + align:start position:0% +make what goes into here we've learned +about the ceramics that go into the + + align:start position:0% +about the ceramics that go into the + + + align:start position:0% +about the ceramics that go into the +catalytic converter and the Catalyst + + align:start position:0% +catalytic converter and the Catalyst + + + align:start position:0% +catalytic converter and the Catalyst +that goes on it and now we've learned + + align:start position:0% +that goes on it and now we've learned + + + align:start position:0% +that goes on it and now we've learned +about diffusion and everything that goes + + align:start position:0% +about diffusion and everything that goes + + + align:start position:0% +about diffusion and everything that goes +into the oxygen sensor that's why I tell + + align:start position:0% +into the oxygen sensor that's why I tell + + + align:start position:0% +into the oxygen sensor that's why I tell +you chemistry is the central science to + + align:start position:0% +you chemistry is the central science to + + + align:start position:0% +you chemistry is the central science to +Energy Efficiency + + align:start position:0% +Energy Efficiency + + + align:start position:0% +Energy Efficiency +and environmental Conservancy learn your + + align:start position:0% +and environmental Conservancy learn your + + + align:start position:0% +and environmental Conservancy learn your +Chemistry it's the most important + + align:start position:0% +Chemistry it's the most important + + + align:start position:0% +Chemistry it's the most important +subject and with that I'll say have a + + align:start position:0% +subject and with that I'll say have a + + + align:start position:0% +subject and with that I'll say have a +nice day and we'll see you on Wednesday \ No newline at end of file diff --git a/L-Sv1oL43ew.txt b/L-Sv1oL43ew.txt new file mode 100644 index 0000000000000000000000000000000000000000..e678091b1236d7861dc3327e175f4a291de1741a --- /dev/null +++ b/L-Sv1oL43ew.txt @@ -0,0 +1,651 @@ +align:start position:0% + +the beach ball strategy is a way to get + + align:start position:0% +the beach ball strategy is a way to get + + + align:start position:0% +the beach ball strategy is a way to get +students who might not want to answer + + align:start position:0% +students who might not want to answer + + + align:start position:0% +students who might not want to answer +questions or be a little less outgoing + + align:start position:0% +questions or be a little less outgoing + + + align:start position:0% +questions or be a little less outgoing +in their answering of questions to + + align:start position:0% +in their answering of questions to + + + align:start position:0% +in their answering of questions to +answer questions so there's a few + + align:start position:0% +answer questions so there's a few + + + align:start position:0% +answer questions so there's a few +different ways to use the beach ball + + align:start position:0% +different ways to use the beach ball + + + align:start position:0% +different ways to use the beach ball +actually and and one is you just uh pose + + align:start position:0% +actually and and one is you just uh pose + + + align:start position:0% +actually and and one is you just uh pose +a question that has enough variation in + + align:start position:0% +a question that has enough variation in + + + align:start position:0% +a question that has enough variation in +the types of responses so you wouldn't + + align:start position:0% +the types of responses so you wouldn't + + + align:start position:0% +the types of responses so you wouldn't +say okay what's 2 plus too as a as an as + + align:start position:0% +say okay what's 2 plus too as a as an as + + + align:start position:0% +say okay what's 2 plus too as a as an as +an example for the beach ball question + + align:start position:0% +an example for the beach ball question + + + align:start position:0% +an example for the beach ball question +you would have to have something that + + align:start position:0% +you would have to have something that + + + align:start position:0% +you would have to have something that +was a little bit more a little bit + + align:start position:0% +was a little bit more a little bit + + + align:start position:0% +was a little bit more a little bit +richer and then you throw the ball at at + + align:start position:0% +richer and then you throw the ball at at + + + align:start position:0% +richer and then you throw the ball at at +one student or up into the up into the + + align:start position:0% +one student or up into the up into the + + + align:start position:0% +one student or up into the up into the +lecture hall if it's a big lecture hall + + align:start position:0% +lecture hall if it's a big lecture hall + + + align:start position:0% +lecture hall if it's a big lecture hall +and whoever catches it has to + + align:start position:0% +and whoever catches it has to + + + align:start position:0% +and whoever catches it has to +respond and that response you share it + + align:start position:0% +respond and that response you share it + + + align:start position:0% +respond and that response you share it +with the group comment on it if you want + + align:start position:0% +with the group comment on it if you want + + + align:start position:0% +with the group comment on it if you want +to comment on it and then that person + + align:start position:0% +to comment on it and then that person + + + align:start position:0% +to comment on it and then that person +who gave the first response throws the + + align:start position:0% +who gave the first response throws the + + + align:start position:0% +who gave the first response throws the +ball to somebody else and then whoever + + align:start position:0% +ball to somebody else and then whoever + + + align:start position:0% +ball to somebody else and then whoever +catches the ball that time responds Etc + + align:start position:0% +catches the ball that time responds Etc + + + align:start position:0% +catches the ball that time responds Etc +um you can use it coupled with a picture + + align:start position:0% +um you can use it coupled with a picture + + + align:start position:0% +um you can use it coupled with a picture +prompt or or a graph so if you show a + + align:start position:0% +prompt or or a graph so if you show a + + + align:start position:0% +prompt or or a graph so if you show a +graph or an image and you say tell me + + align:start position:0% +graph or an image and you say tell me + + + align:start position:0% +graph or an image and you say tell me +one thing tell me something you observe + + align:start position:0% +one thing tell me something you observe + + + align:start position:0% +one thing tell me something you observe +about this image and then you throw the + + align:start position:0% +about this image and then you throw the + + + align:start position:0% +about this image and then you throw the +ball and the person that catches it + + align:start position:0% +ball and the person that catches it + + + align:start position:0% +ball and the person that catches it +first says one thing they observe and + + align:start position:0% +first says one thing they observe and + + + align:start position:0% +first says one thing they observe and +they throw it and the next person says + + align:start position:0% +they throw it and the next person says + + + align:start position:0% +they throw it and the next person says +something that they observed about the + + align:start position:0% +something that they observed about the + + + align:start position:0% +something that they observed about the +picture prompt so that that that gives a + + align:start position:0% +picture prompt so that that that gives a + + + align:start position:0% +picture prompt so that that that gives a +foundation and and it opens up uh space + + align:start position:0% +foundation and and it opens up uh space + + + align:start position:0% +foundation and and it opens up uh space +for lots of + + align:start position:0% +for lots of + + + align:start position:0% +for lots of +responses um it does a the beach ball + + align:start position:0% +responses um it does a the beach ball + + + align:start position:0% +responses um it does a the beach ball +does a few things one is that as the + + align:start position:0% +does a few things one is that as the + + + align:start position:0% +does a few things one is that as the +instructor you don't have to be the one + + align:start position:0% +instructor you don't have to be the one + + + align:start position:0% +instructor you don't have to be the one +that calls on on the students all the + + align:start position:0% +that calls on on the students all the + + + align:start position:0% +that calls on on the students all the +time so the students don't feel like + + align:start position:0% +time so the students don't feel like + + + align:start position:0% +time so the students don't feel like +you're picking on them that you're the + + align:start position:0% +you're picking on them that you're the + + + align:start position:0% +you're picking on them that you're the +one that's cold calling on them and in + + align:start position:0% +one that's cold calling on them and in + + + align:start position:0% +one that's cold calling on them and in +fact you can throw the beach ball + + align:start position:0% +fact you can throw the beach ball + + + align:start position:0% +fact you can throw the beach ball +completely blind the first time close + + align:start position:0% +completely blind the first time close + + + align:start position:0% +completely blind the first time close +your eyes throw the ball and and so + + align:start position:0% +your eyes throw the ball and and so + + + align:start position:0% +your eyes throw the ball and and so +nobody really feels that you've called + + align:start position:0% +nobody really feels that you've called + + + align:start position:0% +nobody really feels that you've called +on them and then subsequently it's other + + align:start position:0% +on them and then subsequently it's other + + + align:start position:0% +on them and then subsequently it's other +students that are throwing the ball so + + align:start position:0% +students that are throwing the ball so + + + align:start position:0% +students that are throwing the ball so +there's no issue about about that you're + + align:start position:0% +there's no issue about about that you're + + + align:start position:0% +there's no issue about about that you're +the one that's picking on the students + + align:start position:0% +the one that's picking on the students + + + align:start position:0% +the one that's picking on the students +um the other thing is it's kind of fun + + align:start position:0% +um the other thing is it's kind of fun + + + align:start position:0% +um the other thing is it's kind of fun +you're throwing the ball around so + + align:start position:0% +you're throwing the ball around so + + + align:start position:0% +you're throwing the ball around so +it uh it's hard to get upset it's hard + + align:start position:0% +it uh it's hard to get upset it's hard + + + align:start position:0% +it uh it's hard to get upset it's hard +to get as a student or nervous that + + align:start position:0% +to get as a student or nervous that + + + align:start position:0% +to get as a student or nervous that +you're going to you're going to have to + + align:start position:0% +you're going to you're going to have to + + + align:start position:0% +you're going to you're going to have to +answer the question and in fact you + + align:start position:0% +answer the question and in fact you + + + align:start position:0% +answer the question and in fact you +could Dodge the ball if you really + + align:start position:0% +could Dodge the ball if you really + + + align:start position:0% +could Dodge the ball if you really +didn't want to answer the question um so + + align:start position:0% +didn't want to answer the question um so + + + align:start position:0% +didn't want to answer the question um so +it's a great way to get students talking + + align:start position:0% +it's a great way to get students talking + + + align:start position:0% +it's a great way to get students talking +and in general it's it's pretty fun and + + align:start position:0% +and in general it's it's pretty fun and + + + align:start position:0% +and in general it's it's pretty fun and +at first I I thought oh I can't really + + align:start position:0% +at first I I thought oh I can't really + + + align:start position:0% +at first I I thought oh I can't really +use this with grad students it's it's + + align:start position:0% +use this with grad students it's it's + + + align:start position:0% +use this with grad students it's it's +too goofy it's too it's too baby or + + align:start position:0% +too goofy it's too it's too baby or + + + align:start position:0% +too goofy it's too it's too baby or +silly but but actually every time I use + + align:start position:0% +silly but but actually every time I use + + + align:start position:0% +silly but but actually every time I use +it with grad students post + + align:start position:0% +it with grad students post + + + align:start position:0% +it with grad students post +everybody seems perfectly fine with it I + + align:start position:0% +everybody seems perfectly fine with it I + + + align:start position:0% +everybody seems perfectly fine with it I +think it's more to do with the nature of + + align:start position:0% +think it's more to do with the nature of + + + align:start position:0% +think it's more to do with the nature of +the question if you just ask stupid + + align:start position:0% +the question if you just ask stupid + + + align:start position:0% +the question if you just ask stupid +questions and throw the ball around + + align:start position:0% +questions and throw the ball around + + + align:start position:0% +questions and throw the ball around +it'll be stupid but if you ask good + + align:start position:0% +it'll be stupid but if you ask good + + + align:start position:0% +it'll be stupid but if you ask good +questions and it's a way for students to + + align:start position:0% +questions and it's a way for students to + + + align:start position:0% +questions and it's a way for students to +get uh to give you their answers then it + + align:start position:0% +get uh to give you their answers then it + + + align:start position:0% +get uh to give you their answers then it +seems to work totally fine that's the + + align:start position:0% +seems to work totally fine that's the + + + align:start position:0% +seems to work totally fine that's the +general way sometimes I'll actually + + align:start position:0% +general way sometimes I'll actually + + + align:start position:0% +general way sometimes I'll actually +write questions on the beach ball and + + align:start position:0% +write questions on the beach ball and + + + align:start position:0% +write questions on the beach ball and +then throw the ball into the into the + + align:start position:0% +then throw the ball into the into the + + + align:start position:0% +then throw the ball into the into the +class and then students are Loosely + + align:start position:0% +class and then students are Loosely + + + align:start position:0% +class and then students are Loosely +supposed to answer the question that's + + align:start position:0% +supposed to answer the question that's + + + align:start position:0% +supposed to answer the question that's +in front of them when they catch the + + align:start position:0% +in front of them when they catch the + + + align:start position:0% +in front of them when they catch the +ball so that's another way to do it um + + align:start position:0% +ball so that's another way to do it um + + + align:start position:0% +ball so that's another way to do it um +but it's a nice inexpensive fairly + + align:start position:0% +but it's a nice inexpensive fairly + + + align:start position:0% +but it's a nice inexpensive fairly +flexible technique \ No newline at end of file diff --git a/M6ibQYbbuq8.txt b/M6ibQYbbuq8.txt new file mode 100644 index 0000000000000000000000000000000000000000..f40128b35aec9bbefc803d609be0bd080126a037 --- /dev/null +++ b/M6ibQYbbuq8.txt @@ -0,0 +1,4168 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +view additional materials from hundreds + + align:start position:0% +view additional materials from hundreds + + + align:start position:0% +view additional materials from hundreds +of MIT courses visit MIT opencourseware + + align:start position:0% +of MIT courses visit MIT opencourseware + + + align:start position:0% +of MIT courses visit MIT opencourseware +at ocw.mit.edu + + align:start position:0% + + + + align:start position:0% + +edgerton's Boomer illustrates the + + align:start position:0% +edgerton's Boomer illustrates the + + + align:start position:0% +edgerton's Boomer illustrates the +induction of a current in a conductor + + align:start position:0% +induction of a current in a conductor + + + align:start position:0% +induction of a current in a conductor +subjected to a Time varying magnetic + + align:start position:0% +subjected to a Time varying magnetic + + + align:start position:0% +subjected to a Time varying magnetic +field and the associated magnetic + + align:start position:0% +field and the associated magnetic + + + align:start position:0% +field and the associated magnetic +forces it illustrates the interplay + + align:start position:0% +forces it illustrates the interplay + + + align:start position:0% +forces it illustrates the interplay +between the laws of feraday ampere and + + align:start position:0% +between the laws of feraday ampere and + + + align:start position:0% +between the laws of feraday ampere and +ohm that determines the distribution + + align:start position:0% +ohm that determines the distribution + + + align:start position:0% +ohm that determines the distribution +duration and magnitude of currents in + + align:start position:0% +duration and magnitude of currents in + + + align:start position:0% +duration and magnitude of currents in +conductors under Magneto quasistatic + + align:start position:0% +conductors under Magneto quasistatic + + + align:start position:0% +conductors under Magneto quasistatic +conditions + + align:start position:0% + + + + align:start position:0% + +the time varying magnetic field will be + + align:start position:0% +the time varying magnetic field will be + + + align:start position:0% +the time varying magnetic field will be +produced by a current through the + + align:start position:0% +produced by a current through the + + + align:start position:0% +produced by a current through the +windings of this + + align:start position:0% +windings of this + + + align:start position:0% +windings of this +coil to produce this current we'll first + + align:start position:0% +coil to produce this current we'll first + + + align:start position:0% +coil to produce this current we'll first +charge this capacitor to 4 + + align:start position:0% +charge this capacitor to 4 + + + align:start position:0% +charge this capacitor to 4 +Kilts and then discharge the capacitor + + align:start position:0% +Kilts and then discharge the capacitor + + + align:start position:0% +Kilts and then discharge the capacitor +through the coil by closing this + + align:start position:0% + + + + align:start position:0% + +switch this is the + + align:start position:0% +switch this is the + + + align:start position:0% +switch this is the +coil the winding wire circulates like + + align:start position:0% +coil the winding wire circulates like + + + align:start position:0% +coil the winding wire circulates like +so and is connected Ed to the capacitors + + align:start position:0% +so and is connected Ed to the capacitors + + + align:start position:0% +so and is connected Ed to the capacitors +in this cabinet by these + + align:start position:0% + + + + align:start position:0% + +leads when the high voltage power supply + + align:start position:0% +leads when the high voltage power supply + + + align:start position:0% +leads when the high voltage power supply +in the cabinet is turned + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +on the capacitor is charged to 4 + + align:start position:0% + + + + align:start position:0% + +Kilts the switch then connects the + + align:start position:0% +Kilts the switch then connects the + + + align:start position:0% +Kilts the switch then connects the +capacitor to the coil it's closed when + + align:start position:0% +capacitor to the coil it's closed when + + + align:start position:0% +capacitor to the coil it's closed when +this button is pushed + + align:start position:0% +this button is pushed + + + align:start position:0% +this button is pushed +[Music] + + align:start position:0% + + + + align:start position:0% + +the switch consists of a spark gap which + + align:start position:0% +the switch consists of a spark gap which + + + align:start position:0% +the switch consists of a spark gap which +we just heard we can see it if we open + + align:start position:0% +we just heard we can see it if we open + + + align:start position:0% +we just heard we can see it if we open +this + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +panel the switch is closed by a spark + + align:start position:0% +panel the switch is closed by a spark + + + align:start position:0% +panel the switch is closed by a spark +cross this + + align:start position:0% +cross this + + + align:start position:0% +cross this +Gap that spark is activated by applying + + align:start position:0% +Gap that spark is activated by applying + + + align:start position:0% +Gap that spark is activated by applying +a voltage to this electrode to make a + + align:start position:0% +a voltage to this electrode to make a + + + align:start position:0% +a voltage to this electrode to make a +smaller electrical breakdown in the + + align:start position:0% + + + + align:start position:0% + +Gap just once we'll bypass the safety + + align:start position:0% +Gap just once we'll bypass the safety + + + align:start position:0% +Gap just once we'll bypass the safety +interlock that ordinarily disconnects + + align:start position:0% +interlock that ordinarily disconnects + + + align:start position:0% +interlock that ordinarily disconnects +the circuit when the panel is + + align:start position:0% + + + + align:start position:0% + +opened then when we push the button we + + align:start position:0% +opened then when we push the button we + + + align:start position:0% +opened then when we push the button we +can not only hear the spark discharge + + align:start position:0% +can not only hear the spark discharge + + + align:start position:0% +can not only hear the spark discharge +that closes the switch but see the + + align:start position:0% +that closes the switch but see the + + + align:start position:0% +that closes the switch but see the +associated flash as as + + align:start position:0% + + + + align:start position:0% + +well maybe we can do it once + + align:start position:0% + + + + align:start position:0% + +more given the initial capacitor voltage + + align:start position:0% +more given the initial capacitor voltage + + + align:start position:0% +more given the initial capacitor voltage +of 4 Kilts and that the coil has 50 + + align:start position:0% +of 4 Kilts and that the coil has 50 + + + align:start position:0% +of 4 Kilts and that the coil has 50 +turns we can use basic principles to + + align:start position:0% +turns we can use basic principles to + + + align:start position:0% +turns we can use basic principles to +estimate the winding current and hence + + align:start position:0% +estimate the winding current and hence + + + align:start position:0% +estimate the winding current and hence +the mag itic field intensity produced by + + align:start position:0% +the mag itic field intensity produced by + + + align:start position:0% +the mag itic field intensity produced by +the + + align:start position:0% +the + + + align:start position:0% +the +coil first we use ampere's integral law + + align:start position:0% +coil first we use ampere's integral law + + + align:start position:0% +coil first we use ampere's integral law +to relate the current to the + + align:start position:0% +to relate the current to the + + + align:start position:0% +to relate the current to the +field the line Contour encloses the + + align:start position:0% +field the line Contour encloses the + + + align:start position:0% +field the line Contour encloses the +current in the + + align:start position:0% + + + + align:start position:0% + +coil ampers integral law applied to this + + align:start position:0% +coil ampers integral law applied to this + + + align:start position:0% +coil ampers integral law applied to this +Contour + + align:start position:0% + + + + align:start position:0% + +C given that the Contour has a radius + + align:start position:0% +C given that the Contour has a radius + + + align:start position:0% +C given that the Contour has a radius +equal to the average r radius of the + + align:start position:0% +equal to the average r radius of the + + + align:start position:0% +equal to the average r radius of the +coil winding + + align:start position:0% +coil winding + + + align:start position:0% +coil winding +a the Contour integral is approximated + + align:start position:0% +a the Contour integral is approximated + + + align:start position:0% +a the Contour integral is approximated +by the circumference 2 pi a multiplied + + align:start position:0% +by the circumference 2 pi a multiplied + + + align:start position:0% +by the circumference 2 pi a multiplied +by the average magnetic field + + align:start position:0% +by the average magnetic field + + + align:start position:0% +by the average magnetic field +intensity the current passing through + + align:start position:0% +intensity the current passing through + + + align:start position:0% +intensity the current passing through +the enclosed + + align:start position:0% + + + + align:start position:0% + +surface is the number of turns N Sub + + align:start position:0% +surface is the number of turns N Sub + + + align:start position:0% +surface is the number of turns N Sub +one times the + + align:start position:0% +one times the + + + align:start position:0% +one times the +current so we can solve for the average + + align:start position:0% +current so we can solve for the average + + + align:start position:0% +current so we can solve for the average +magnetic field intens + + align:start position:0% +magnetic field intens + + + align:start position:0% +magnetic field intens +density to use this expression we need + + align:start position:0% +density to use this expression we need + + + align:start position:0% +density to use this expression we need +to know the coil current I + + align:start position:0% + + + + align:start position:0% + +sub1 if the resistive loss of the + + align:start position:0% +sub1 if the resistive loss of the + + + align:start position:0% +sub1 if the resistive loss of the +circuit is small compared to the + + align:start position:0% +circuit is small compared to the + + + align:start position:0% +circuit is small compared to the +inductive and capacitive energy storage + + align:start position:0% +inductive and capacitive energy storage + + + align:start position:0% +inductive and capacitive energy storage +this current is a damped + + align:start position:0% +this current is a damped + + + align:start position:0% +this current is a damped +oscillation in that case after a quarter + + align:start position:0% +oscillation in that case after a quarter + + + align:start position:0% +oscillation in that case after a quarter +of one oscillation all of the energy + + align:start position:0% +of one oscillation all of the energy + + + align:start position:0% +of one oscillation all of the energy +initially stored in the capacitor + + align:start position:0% +initially stored in the capacitor + + + align:start position:0% +initially stored in the capacitor +essentially ends up stored in the + + align:start position:0% +essentially ends up stored in the + + + align:start position:0% +essentially ends up stored in the +inductor + + align:start position:0% + + + + align:start position:0% + +the peak energy in the + + align:start position:0% +the peak energy in the + + + align:start position:0% +the peak energy in the +capacitor is 1/2 the capacitance c times + + align:start position:0% +capacitor is 1/2 the capacitance c times + + + align:start position:0% +capacitor is 1/2 the capacitance c times +the square of the initial + + align:start position:0% +the square of the initial + + + align:start position:0% +the square of the initial +voltage the peak energy in the coil a + + align:start position:0% +voltage the peak energy in the coil a + + + align:start position:0% +voltage the peak energy in the coil a +quarter of a cycle later is 1 half its + + align:start position:0% +quarter of a cycle later is 1 half its + + + align:start position:0% +quarter of a cycle later is 1 half its +inductance times the peak current + + align:start position:0% +inductance times the peak current + + + align:start position:0% +inductance times the peak current +squared so the peak coil current is + + align:start position:0% +squared so the peak coil current is + + + align:start position:0% +squared so the peak coil current is +proportional to the initial capacitor + + align:start position:0% +proportional to the initial capacitor + + + align:start position:0% +proportional to the initial capacitor +voltage to use this expression we must + + align:start position:0% +voltage to use this expression we must + + + align:start position:0% +voltage to use this expression we must +estimate the coil indu + + align:start position:0% + + + + align:start position:0% + +remember ampers law was used to find + + align:start position:0% +remember ampers law was used to find + + + align:start position:0% +remember ampers law was used to find +this average magnetic field + + align:start position:0% + + + + align:start position:0% + +intensity the average flux linked by all + + align:start position:0% +intensity the average flux linked by all + + + align:start position:0% +intensity the average flux linked by all +the turns of the coil is the number of + + align:start position:0% +the turns of the coil is the number of + + + align:start position:0% +the turns of the coil is the number of +turns times the average coil + + align:start position:0% +turns times the average coil + + + align:start position:0% +turns times the average coil +area multiplied by this flux + + align:start position:0% + + + + align:start position:0% + +density if we use our approximate field + + align:start position:0% +density if we use our approximate field + + + align:start position:0% +density if we use our approximate field +intensity to evaluate this flux we see + + align:start position:0% +intensity to evaluate this flux we see + + + align:start position:0% +intensity to evaluate this flux we see +that it is proportional to + + align:start position:0% +that it is proportional to + + + align:start position:0% +that it is proportional to +i1 the coefficient is the desired coil + + align:start position:0% + + + + align:start position:0% + +inductance for our coil a is on the + + align:start position:0% +inductance for our coil a is on the + + + align:start position:0% +inductance for our coil a is on the +order of 7 + + align:start position:0% +order of 7 + + + align:start position:0% +order of 7 +cm there are about 50 + + align:start position:0% +cm there are about 50 + + + align:start position:0% +cm there are about 50 +turns so the coil inductance is about + + align:start position:0% +turns so the coil inductance is about + + + align:start position:0% +turns so the coil inductance is about +1/10 of a + + align:start position:0% +1/10 of a + + + align:start position:0% +1/10 of a +millihenry in turn we can now + + align:start position:0% +millihenry in turn we can now + + + align:start position:0% +millihenry in turn we can now +approximate the peak coil + + align:start position:0% +approximate the peak coil + + + align:start position:0% +approximate the peak coil +current the capacitance is 16 + + align:start position:0% +current the capacitance is 16 + + + align:start position:0% +current the capacitance is 16 +microfarads so for an initial voltage of + + align:start position:0% +microfarads so for an initial voltage of + + + align:start position:0% +microfarads so for an initial voltage of + + align:start position:0% + + + align:start position:0% +Kilts the peak coil current is about + + align:start position:0% +Kilts the peak coil current is about + + + align:start position:0% +Kilts the peak coil current is about +1,600 + + align:start position:0% +1,600 + + + align:start position:0% +1,600 +amp from this current it follows from + + align:start position:0% +amp from this current it follows from + + + align:start position:0% +amp from this current it follows from +ampers law that the peak magnetic field + + align:start position:0% +ampers law that the peak magnetic field + + + align:start position:0% +ampers law that the peak magnetic field +intensity is 1.8 * 10 5th amps per + + align:start position:0% +intensity is 1.8 * 10 5th amps per + + + align:start position:0% +intensity is 1.8 * 10 5th amps per +meter in free space the peak flux + + align:start position:0% +meter in free space the peak flux + + + align:start position:0% +meter in free space the peak flux +density is therefore 23 T + + align:start position:0% +density is therefore 23 T + + + align:start position:0% +density is therefore 23 T +Tesla about 2300 + + align:start position:0% + + + + align:start position:0% + +Gus the energy oscillates back and forth + + align:start position:0% +Gus the energy oscillates back and forth + + + align:start position:0% +Gus the energy oscillates back and forth +between the capacitor and the + + align:start position:0% +between the capacitor and the + + + align:start position:0% +between the capacitor and the +inductor provided that the circuit + + align:start position:0% +inductor provided that the circuit + + + align:start position:0% +inductor provided that the circuit +resistance is not too large this is the + + align:start position:0% +resistance is not too large this is the + + + align:start position:0% +resistance is not too large this is the +frequency of the + + align:start position:0% +frequency of the + + + align:start position:0% +frequency of the +oscillation once again using the + + align:start position:0% +oscillation once again using the + + + align:start position:0% +oscillation once again using the +inductance of 1/10 + + align:start position:0% +inductance of 1/10 + + + align:start position:0% +inductance of 1/10 +mhenry the capacitance of 16 + + align:start position:0% +mhenry the capacitance of 16 + + + align:start position:0% +mhenry the capacitance of 16 +microfarads we estimate the frequency to + + align:start position:0% +microfarads we estimate the frequency to + + + align:start position:0% +microfarads we estimate the frequency to +be about 4 + + align:start position:0% + + + + align:start position:0% + +khz before we go on let's see how well + + align:start position:0% +khz before we go on let's see how well + + + align:start position:0% +khz before we go on let's see how well +we've approximated the current and + + align:start position:0% +we've approximated the current and + + + align:start position:0% +we've approximated the current and +field this current probe will link one + + align:start position:0% +field this current probe will link one + + + align:start position:0% +field this current probe will link one +of the wires connected to the + + align:start position:0% + + + + align:start position:0% + +coil we display the coil current on the + + align:start position:0% +coil we display the coil current on the + + + align:start position:0% +coil we display the coil current on the +lower scope + + align:start position:0% +lower scope + + + align:start position:0% +lower scope +trace the voltage induced at the + + align:start position:0% +trace the voltage induced at the + + + align:start position:0% +trace the voltage induced at the +terminals of this + + align:start position:0% +terminals of this + + + align:start position:0% +terminals of this +coil by the time ing magnetic flux + + align:start position:0% +coil by the time ing magnetic flux + + + align:start position:0% +coil by the time ing magnetic flux +density will be used to deduce + + align:start position:0% +density will be used to deduce + + + align:start position:0% +density will be used to deduce +B this voltage will be displayed as the + + align:start position:0% +B this voltage will be displayed as the + + + align:start position:0% +B this voltage will be displayed as the +upper scope + + align:start position:0% + + + + align:start position:0% + +Trace here are the responses to the + + align:start position:0% +Trace here are the responses to the + + + align:start position:0% +Trace here are the responses to the +discharge of the + + align:start position:0% + + + + align:start position:0% + +capacitor the time axis is 2/10 of a + + align:start position:0% +capacitor the time axis is 2/10 of a + + + align:start position:0% +capacitor the time axis is 2/10 of a +millisecond per + + align:start position:0% +millisecond per + + + align:start position:0% +millisecond per +division so the period of the + + align:start position:0% +division so the period of the + + + align:start position:0% +division so the period of the +oscillation is about 1/3 of a + + align:start position:0% +oscillation is about 1/3 of a + + + align:start position:0% +oscillation is about 1/3 of a +millisecond the oscillation frequency is + + align:start position:0% +millisecond the oscillation frequency is + + + align:start position:0% +millisecond the oscillation frequency is +roughly the predicted 4 + + align:start position:0% +roughly the predicted 4 + + + align:start position:0% +roughly the predicted 4 +khz the duration of the lower Trace + + align:start position:0% +khz the duration of the lower Trace + + + align:start position:0% +khz the duration of the lower Trace +current and hence of the field is on the + + align:start position:0% +current and hence of the field is on the + + + align:start position:0% +current and hence of the field is on the +order of 1 + + align:start position:0% + + + + align:start position:0% + +millisecond the peak in the current on + + align:start position:0% +millisecond the peak in the current on + + + align:start position:0% +millisecond the peak in the current on +the lower Trace is about one + + align:start position:0% +the lower Trace is about one + + + align:start position:0% +the lower Trace is about one +division there are 1,000 amps per + + align:start position:0% +division there are 1,000 amps per + + + align:start position:0% +division there are 1,000 amps per +division so the peak current is about + + align:start position:0% +division so the peak current is about + + + align:start position:0% +division so the peak current is about +1,000 amps + + align:start position:0% +1,000 amps + + + align:start position:0% +1,000 amps +this is in the range of the estimated + + align:start position:0% +this is in the range of the estimated + + + align:start position:0% +this is in the range of the estimated +value of 1600 amps remember we've not + + align:start position:0% +value of 1600 amps remember we've not + + + align:start position:0% +value of 1600 amps remember we've not +accounted for losses in the spark gap in + + align:start position:0% +accounted for losses in the spark gap in + + + align:start position:0% +accounted for losses in the spark gap in +the + + align:start position:0% + + + + align:start position:0% + +coil finally the voltage of our + + align:start position:0% +coil finally the voltage of our + + + align:start position:0% +coil finally the voltage of our +induction Loop the upper Trace is + + align:start position:0% +induction Loop the upper Trace is + + + align:start position:0% +induction Loop the upper Trace is +related to the coil area and turns by + + align:start position:0% +related to the coil area and turns by + + + align:start position:0% +related to the coil area and turns by +Faraday's + + align:start position:0% +Faraday's + + + align:start position:0% +Faraday's +law the coil voltage is the rate of + + align:start position:0% +law the coil voltage is the rate of + + + align:start position:0% +law the coil voltage is the rate of +change of the flux the product of its + + align:start position:0% +change of the flux the product of its + + + align:start position:0% +change of the flux the product of its +area its turns and the magnetic flux + + align:start position:0% +area its turns and the magnetic flux + + + align:start position:0% +area its turns and the magnetic flux +density we approximate the derivative by + + align:start position:0% +density we approximate the derivative by + + + align:start position:0% +density we approximate the derivative by +Omega so this is + + align:start position:0% +Omega so this is + + + align:start position:0% +Omega so this is +B there are 200 turns the area is 2.4 * + + align:start position:0% +B there are 200 turns the area is 2.4 * + + + align:start position:0% +B there are 200 turns the area is 2.4 * +10-4 M + + align:start position:0% +10-4 M + + + align:start position:0% +10-4 M +squar the estimated frequency is 4 + + align:start position:0% +squar the estimated frequency is 4 + + + align:start position:0% +squar the estimated frequency is 4 +khz and the peak voltage is 500 + + align:start position:0% +khz and the peak voltage is 500 + + + align:start position:0% +khz and the peak voltage is 500 +volt we conclude that near the center of + + align:start position:0% +volt we conclude that near the center of + + + align:start position:0% +volt we conclude that near the center of +the coil the peak magnetic flux density + + align:start position:0% +the coil the peak magnetic flux density + + + align:start position:0% +the coil the peak magnetic flux density +is4 Tesla + + align:start position:0% +is4 Tesla + + + align:start position:0% +is4 Tesla +4,000 + + align:start position:0% + + + + align:start position:0% + +gaus our estimate of the space average + + align:start position:0% +gaus our estimate of the space average + + + align:start position:0% +gaus our estimate of the space average +for this peak value of the flux density + + align:start position:0% +for this peak value of the flux density + + + align:start position:0% +for this peak value of the flux density +was 2,300 GA somewhat less as it should + + align:start position:0% + + + + align:start position:0% + +be now suppose that a conducting disc is + + align:start position:0% +be now suppose that a conducting disc is + + + align:start position:0% +be now suppose that a conducting disc is +placed just above the + + align:start position:0% +placed just above the + + + align:start position:0% +placed just above the +coil what's the current induced in the + + align:start position:0% +coil what's the current induced in the + + + align:start position:0% +coil what's the current induced in the +disc to obtain a rough approximation We + + align:start position:0% +disc to obtain a rough approximation We + + + align:start position:0% +disc to obtain a rough approximation We +Begin by applying Faraday's integral law + + align:start position:0% +Begin by applying Faraday's integral law + + + align:start position:0% +Begin by applying Faraday's integral law +to this this + + align:start position:0% +to this this + + + align:start position:0% +to this this +Contour it encloses the surface s lying + + align:start position:0% +Contour it encloses the surface s lying + + + align:start position:0% +Contour it encloses the surface s lying +in the plane of the + + align:start position:0% + + + + align:start position:0% + +disc the line integral of the azimuthal + + align:start position:0% +disc the line integral of the azimuthal + + + align:start position:0% +disc the line integral of the azimuthal +electric + + align:start position:0% +electric + + + align:start position:0% +electric +field is the product of the average + + align:start position:0% +field is the product of the average + + + align:start position:0% +field is the product of the average +circumference and that electric field + + align:start position:0% +circumference and that electric field + + + align:start position:0% +circumference and that electric field +intensity it's equal to the time rate of + + align:start position:0% +intensity it's equal to the time rate of + + + align:start position:0% +intensity it's equal to the time rate of +change of the net flux through the + + align:start position:0% +change of the net flux through the + + + align:start position:0% +change of the net flux through the +enclosed area Pi a^ 2 + + align:start position:0% + + + + align:start position:0% + +the current density circulating in the + + align:start position:0% +the current density circulating in the + + + align:start position:0% +the current density circulating in the +disc follows from this field and ohms + + align:start position:0% + + + + align:start position:0% + +law the disc could represent a + + align:start position:0% +law the disc could represent a + + + align:start position:0% +law the disc could represent a +hand in that case the experiment can + + align:start position:0% +hand in that case the experiment can + + + align:start position:0% +hand in that case the experiment can +literally give a feel for the + + align:start position:0% +literally give a feel for the + + + align:start position:0% +literally give a feel for the +consequence of subjecting a conductor to + + align:start position:0% +consequence of subjecting a conductor to + + + align:start position:0% +consequence of subjecting a conductor to +a Time varying magnetic + + align:start position:0% +a Time varying magnetic + + + align:start position:0% +a Time varying magnetic +field if the disc represents a hand what + + align:start position:0% +field if the disc represents a hand what + + + align:start position:0% +field if the disc represents a hand what +current density would be + + align:start position:0% + + + + align:start position:0% + +felt here's our estimated current + + align:start position:0% +felt here's our estimated current + + + align:start position:0% +felt here's our estimated current +density for flush the conductivity is on + + align:start position:0% +density for flush the conductivity is on + + + align:start position:0% +density for flush the conductivity is on +the order of one semen per + + align:start position:0% +the order of one semen per + + + align:start position:0% +the order of one semen per +meter here's the permeability of free + + align:start position:0% +meter here's the permeability of free + + + align:start position:0% +meter here's the permeability of free +space and the average coil + + align:start position:0% +space and the average coil + + + align:start position:0% +space and the average coil +radius the angular frequency roughly 2 + + align:start position:0% +radius the angular frequency roughly 2 + + + align:start position:0% +radius the angular frequency roughly 2 +pi * 4 + + align:start position:0% +pi * 4 + + + align:start position:0% +pi * 4 +khz this is our calculated average field + + align:start position:0% +khz this is our calculated average field + + + align:start position:0% +khz this is our calculated average field +intensity so so the current density is + + align:start position:0% +intensity so so the current density is + + + align:start position:0% +intensity so so the current density is +approximately 200 amps per square + + align:start position:0% +approximately 200 amps per square + + + align:start position:0% +approximately 200 amps per square +met because a square cm is typical of + + align:start position:0% +met because a square cm is typical of + + + align:start position:0% +met because a square cm is typical of +the cross-sectional area through a + + align:start position:0% +the cross-sectional area through a + + + align:start position:0% +the cross-sectional area through a +hand we have a better feel for this + + align:start position:0% +hand we have a better feel for this + + + align:start position:0% +hand we have a better feel for this +number expressed as 20 milliamps per + + align:start position:0% +number expressed as 20 milliamps per + + + align:start position:0% +number expressed as 20 milliamps per +square + + align:start position:0% +square + + + align:start position:0% +square +cm this is more than enough to give a + + align:start position:0% +cm this is more than enough to give a + + + align:start position:0% +cm this is more than enough to give a +good + + align:start position:0% + + + + align:start position:0% + +shock magnetic field created by the coil + + align:start position:0% +shock magnetic field created by the coil + + + align:start position:0% +shock magnetic field created by the coil +is + + align:start position:0% +is + + + align:start position:0% +is +non-uniform far away that of a + + align:start position:0% +non-uniform far away that of a + + + align:start position:0% +non-uniform far away that of a +dipole so we can discern what we're + + align:start position:0% +dipole so we can discern what we're + + + align:start position:0% +dipole so we can discern what we're +getting into by feeling the induced + + align:start position:0% +getting into by feeling the induced + + + align:start position:0% +getting into by feeling the induced +current in + + align:start position:0% +current in + + + align:start position:0% +current in +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +stages the sensation is of a short + + align:start position:0% +stages the sensation is of a short + + + align:start position:0% +stages the sensation is of a short +duration + + align:start position:0% +duration + + + align:start position:0% +duration +twinge much as would be expected for a + + align:start position:0% +twinge much as would be expected for a + + + align:start position:0% +twinge much as would be expected for a +pulse that lasts 1 millisecond + + align:start position:0% + + + + align:start position:0% + +uh I've been given to understand that + + align:start position:0% +uh I've been given to understand that + + + align:start position:0% +uh I've been given to understand that +Professor Zan is not going to try it + + align:start position:0% +Professor Zan is not going to try it + + + align:start position:0% +Professor Zan is not going to try it +with his hand lower than + + align:start position:0% + + + + align:start position:0% + +this so that you can see evidence of the + + align:start position:0% +this so that you can see evidence of the + + + align:start position:0% +this so that you can see evidence of the +field that you can't feel + + align:start position:0% +field that you can't feel + + + align:start position:0% +field that you can't feel +firsthand let's replace his hand by this + + align:start position:0% +firsthand let's replace his hand by this + + + align:start position:0% +firsthand let's replace his hand by this +wire + + align:start position:0% + + + + align:start position:0% + +Loop the wire is open at this + + align:start position:0% +Loop the wire is open at this + + + align:start position:0% +Loop the wire is open at this +point with the ends barely touching + + align:start position:0% + + + + align:start position:0% + +so the field induced around the + + align:start position:0% + + + + align:start position:0% + +Contour is concentrated at the + + align:start position:0% +Contour is concentrated at the + + + align:start position:0% +Contour is concentrated at the +Gap we go to a higher f- stop to protect + + align:start position:0% +Gap we go to a higher f- stop to protect + + + align:start position:0% +Gap we go to a higher f- stop to protect +the + + align:start position:0% + + + + align:start position:0% + +camera the integral of the electric + + align:start position:0% +camera the integral of the electric + + + align:start position:0% +camera the integral of the electric +field intensity is concentrated in a gap + + align:start position:0% +field intensity is concentrated in a gap + + + align:start position:0% +field intensity is concentrated in a gap +region that is initially relatively + + align:start position:0% +region that is initially relatively + + + align:start position:0% +region that is initially relatively +insulating so so the electric field + + align:start position:0% +insulating so so the electric field + + + align:start position:0% +insulating so so the electric field +intensity between the almost touching + + align:start position:0% +intensity between the almost touching + + + align:start position:0% +intensity between the almost touching +wires is enough to produce a + + align:start position:0% + + + + align:start position:0% + +spark the conductivity of this aluminum + + align:start position:0% +spark the conductivity of this aluminum + + + align:start position:0% +spark the conductivity of this aluminum +disc is more than 10 million times + + align:start position:0% +disc is more than 10 million times + + + align:start position:0% +disc is more than 10 million times +larger than for human flesh and there's + + align:start position:0% +larger than for human flesh and there's + + + align:start position:0% +larger than for human flesh and there's +no Gap to limit the induced current + + align:start position:0% + + + + align:start position:0% + +if we presume that the coil links the + + align:start position:0% +if we presume that the coil links the + + + align:start position:0% +if we presume that the coil links the +aluminum disc with the same magnetic + + align:start position:0% +aluminum disc with the same magnetic + + + align:start position:0% +aluminum disc with the same magnetic +flux as it does the hand the laws of + + align:start position:0% +flux as it does the hand the laws of + + + align:start position:0% +flux as it does the hand the laws of +Faraday and ohm would say that the + + align:start position:0% +Faraday and ohm would say that the + + + align:start position:0% +Faraday and ohm would say that the +current density should be more than 10 + + align:start position:0% +current density should be more than 10 + + + align:start position:0% +current density should be more than 10 +million times + + align:start position:0% +million times + + + align:start position:0% +million times +larger the conductivity of the disc is + + align:start position:0% +larger the conductivity of the disc is + + + align:start position:0% +larger the conductivity of the disc is +3.5 * 10 7 seans per + + align:start position:0% +3.5 * 10 7 seans per + + + align:start position:0% +3.5 * 10 7 seans per +meter rather than about one as it was + + align:start position:0% +meter rather than about one as it was + + + align:start position:0% +meter rather than about one as it was +for the + + align:start position:0% + + + + align:start position:0% + +hand however the current induced in the + + align:start position:0% +hand however the current induced in the + + + align:start position:0% +hand however the current induced in the +dis is so large that it produces a field + + align:start position:0% +dis is so large that it produces a field + + + align:start position:0% +dis is so large that it produces a field +of its own that limits the flux actually + + align:start position:0% +of its own that limits the flux actually + + + align:start position:0% +of its own that limits the flux actually +linked by the + + align:start position:0% + + + + align:start position:0% + +dis the current induced in the + + align:start position:0% + + + + align:start position:0% + +disc is so large that it produces a + + align:start position:0% +disc is so large that it produces a + + + align:start position:0% +disc is so large that it produces a +field of its + + align:start position:0% +field of its + + + align:start position:0% +field of its +own that limits the flux actually linked + + align:start position:0% +own that limits the flux actually linked + + + align:start position:0% +own that limits the flux actually linked +by the + + align:start position:0% + + + + align:start position:0% + +dis this induced magnetic field tends to + + align:start position:0% +dis this induced magnetic field tends to + + + align:start position:0% +dis this induced magnetic field tends to +Buck out the field from the coil + + align:start position:0% + + + + align:start position:0% + +to see this let's again use ampers + + align:start position:0% +to see this let's again use ampers + + + align:start position:0% +to see this let's again use ampers +integral law to estimate the magnetic + + align:start position:0% +integral law to estimate the magnetic + + + align:start position:0% +integral law to estimate the magnetic +field + + align:start position:0% +field + + + align:start position:0% +field +intensity this time it's the field + + align:start position:0% +intensity this time it's the field + + + align:start position:0% +intensity this time it's the field +associated with a current that is + + align:start position:0% +associated with a current that is + + + align:start position:0% +associated with a current that is +induced in the + + align:start position:0% +induced in the + + + align:start position:0% +induced in the +dis the result is the same as it was for + + align:start position:0% +dis the result is the same as it was for + + + align:start position:0% +dis the result is the same as it was for +the + + align:start position:0% +the + + + align:start position:0% +the +coil except that now that current is in + + align:start position:0% +coil except that now that current is in + + + align:start position:0% +coil except that now that current is in +the + + align:start position:0% + + + + align:start position:0% + +dis this current is roughly the current + + align:start position:0% +dis this current is roughly the current + + + align:start position:0% +dis this current is roughly the current +density + + align:start position:0% +density + + + align:start position:0% +density +times the average cross-sectional area + + align:start position:0% +times the average cross-sectional area + + + align:start position:0% +times the average cross-sectional area +of the + + align:start position:0% +of the + + + align:start position:0% +of the +disc the average radius a times the disc + + align:start position:0% +disc the average radius a times the disc + + + align:start position:0% +disc the average radius a times the disc +thickness + + align:start position:0% + + + + align:start position:0% + +Delta provided this induced field is not + + align:start position:0% +Delta provided this induced field is not + + + align:start position:0% +Delta provided this induced field is not +too large compared to that from the coil + + align:start position:0% +too large compared to that from the coil + + + align:start position:0% +too large compared to that from the coil +we've already approximated this current + + align:start position:0% + + + + align:start position:0% + +density so we can now evaluate the ratio + + align:start position:0% +density so we can now evaluate the ratio + + + align:start position:0% +density so we can now evaluate the ratio +of the field associated with the disc + + align:start position:0% +of the field associated with the disc + + + align:start position:0% +of the field associated with the disc +current to that imposed by the coil + + align:start position:0% +current to that imposed by the coil + + + align:start position:0% +current to that imposed by the coil +current with the time rate of change + + align:start position:0% +current with the time rate of change + + + align:start position:0% +current with the time rate of change +taken as being roughly the angular + + align:start position:0% +taken as being roughly the angular + + + align:start position:0% +taken as being roughly the angular +frequency times the peak composed field + + align:start position:0% +frequency times the peak composed field + + + align:start position:0% +frequency times the peak composed field +intensity this ratio is within 4 Pi of + + align:start position:0% +intensity this ratio is within 4 Pi of + + + align:start position:0% +intensity this ratio is within 4 Pi of +the product of the angular frequency and + + align:start position:0% +the product of the angular frequency and + + + align:start position:0% +the product of the angular frequency and +the Magnetic diffusion + + align:start position:0% +the Magnetic diffusion + + + align:start position:0% +the Magnetic diffusion +time this time is based on the geometric + + align:start position:0% +time this time is based on the geometric + + + align:start position:0% +time this time is based on the geometric +mean of the dis + + align:start position:0% +mean of the dis + + + align:start position:0% +mean of the dis +thickness and its average + + align:start position:0% + + + + align:start position:0% + +radius if the frequency is high + + align:start position:0% +radius if the frequency is high + + + align:start position:0% +radius if the frequency is high +or this magnetic diffusion time is long + + align:start position:0% +or this magnetic diffusion time is long + + + align:start position:0% +or this magnetic diffusion time is long +the current induced in the dis is large + + align:start position:0% +the current induced in the dis is large + + + align:start position:0% +the current induced in the dis is large +enough to prevent much of the magnetic + + align:start position:0% +enough to prevent much of the magnetic + + + align:start position:0% +enough to prevent much of the magnetic +flux from the coil penetrating through + + align:start position:0% +flux from the coil penetrating through + + + align:start position:0% +flux from the coil penetrating through +its + + align:start position:0% +its + + + align:start position:0% +its +surface in the limit where Omega to m is + + align:start position:0% +surface in the limit where Omega to m is + + + align:start position:0% +surface in the limit where Omega to m is +large the dis acts as a secondary of an + + align:start position:0% +large the dis acts as a secondary of an + + + align:start position:0% +large the dis acts as a secondary of an +ideal + + align:start position:0% + + + + align:start position:0% + +Transformer if the coil current is like + + align:start position:0% + + + + align:start position:0% + +this its induced field is upward + + align:start position:0% + + + + align:start position:0% + +the current in the dis then + + align:start position:0% + + + + align:start position:0% + +responds so as to Buck out this + + align:start position:0% + + + + align:start position:0% + +flux so the disc current is in the + + align:start position:0% +flux so the disc current is in the + + + align:start position:0% +flux so the disc current is in the +opposite direction of the coil + + align:start position:0% + + + + align:start position:0% + +current is the product of the frequency + + align:start position:0% +current is the product of the frequency + + + align:start position:0% +current is the product of the frequency +and the Magnetic diffusion time for the + + align:start position:0% +and the Magnetic diffusion time for the + + + align:start position:0% +and the Magnetic diffusion time for the +aluminum + + align:start position:0% +aluminum + + + align:start position:0% +aluminum +disc large enough that it does tend to + + align:start position:0% +disc large enough that it does tend to + + + align:start position:0% +disc large enough that it does tend to +Buck out the imposed field + + align:start position:0% + + + + align:start position:0% + +first let's evaluate to + + align:start position:0% +first let's evaluate to + + + align:start position:0% +first let's evaluate to +M the thickness is 2 + + align:start position:0% +M the thickness is 2 + + + align:start position:0% +M the thickness is 2 +mm the average radius is 7 + + align:start position:0% +mm the average radius is 7 + + + align:start position:0% +mm the average radius is 7 +cm and the conductivity of aluminum is + + align:start position:0% +cm and the conductivity of aluminum is + + + align:start position:0% +cm and the conductivity of aluminum is +3.5 * 10 7th Seaman per + + align:start position:0% +3.5 * 10 7th Seaman per + + + align:start position:0% +3.5 * 10 7th Seaman per +meter so TM is 6 + + align:start position:0% + + + + align:start position:0% + +milliseconds the ratio of H induced to H + + align:start position:0% +milliseconds the ratio of H induced to H + + + align:start position:0% +milliseconds the ratio of H induced to H +imposed Omega to over 4 Pi is about 12 + + align:start position:0% + + + + align:start position:0% + +12 with the aluminum disc we are indeed + + align:start position:0% +12 with the aluminum disc we are indeed + + + align:start position:0% +12 with the aluminum disc we are indeed +in the range where the disc current + + align:start position:0% +in the range where the disc current + + + align:start position:0% +in the range where the disc current +produces a field that bucks out the coil + + align:start position:0% + + + + align:start position:0% + +current according to our approximate + + align:start position:0% +current according to our approximate + + + align:start position:0% +current according to our approximate +analysis the net field should tend to be + + align:start position:0% +analysis the net field should tend to be + + + align:start position:0% +analysis the net field should tend to be +shielded out of the disc by its own + + align:start position:0% +shielded out of the disc by its own + + + align:start position:0% +shielded out of the disc by its own +current the net field tends to be + + align:start position:0% +current the net field tends to be + + + align:start position:0% +current the net field tends to be +tangential to the + + align:start position:0% +tangential to the + + + align:start position:0% +tangential to the +disc one result is a net upward force on + + align:start position:0% +disc one result is a net upward force on + + + align:start position:0% +disc one result is a net upward force on +the disc + + align:start position:0% +the disc + + + align:start position:0% +the disc +this force is the result of a force + + align:start position:0% +this force is the result of a force + + + align:start position:0% +this force is the result of a force +density J crossed with + + align:start position:0% + + + + align:start position:0% + +B + + align:start position:0% + + + + align:start position:0% + +J crossed with + + align:start position:0% + + + + align:start position:0% + +B the force can be used to shape metals + + align:start position:0% + + + + align:start position:0% + +here the upward force is evident in the + + align:start position:0% +here the upward force is evident in the + + + align:start position:0% +here the upward force is evident in the +shaping of the outer edge of a foil disc + + align:start position:0% + + + + align:start position:0% + +for this experiment we use three times + + align:start position:0% +for this experiment we use three times + + + align:start position:0% +for this experiment we use three times +as much + + align:start position:0% + + + + align:start position:0% + +capacitance if the force can be used to + + align:start position:0% +capacitance if the force can be used to + + + align:start position:0% +capacitance if the force can be used to +shape the metal it can also be used to + + align:start position:0% +shape the metal it can also be used to + + + align:start position:0% +shape the metal it can also be used to +launch the + + align:start position:0% +launch the + + + align:start position:0% +launch the +disc if we leave the disc alone will it + + align:start position:0% +disc if we leave the disc alone will it + + + align:start position:0% +disc if we leave the disc alone will it +lift off after the button is + + align:start position:0% +lift off after the button is + + + align:start position:0% +lift off after the button is +pushed it's tempting to take an + + align:start position:0% +pushed it's tempting to take an + + + align:start position:0% +pushed it's tempting to take an +experimental approach but it's more fun + + align:start position:0% +experimental approach but it's more fun + + + align:start position:0% +experimental approach but it's more fun +to first see what we + + align:start position:0% + + + + align:start position:0% + +predict the net force on the disc is the + + align:start position:0% +predict the net force on the disc is the + + + align:start position:0% +predict the net force on the disc is the +force density J crossb integrated over + + align:start position:0% +force density J crossb integrated over + + + align:start position:0% +force density J crossb integrated over +the disc + + align:start position:0% +the disc + + + align:start position:0% +the disc +volume essentially this is the surface + + align:start position:0% +volume essentially this is the surface + + + align:start position:0% +volume essentially this is the surface +current density in the + + align:start position:0% +current density in the + + + align:start position:0% +current density in the +dis times the magnetic flux density in + + align:start position:0% +dis times the magnetic flux density in + + + align:start position:0% +dis times the magnetic flux density in +the + + align:start position:0% +the + + + align:start position:0% +the +gap multiplied by the dis + + align:start position:0% +gap multiplied by the dis + + + align:start position:0% +gap multiplied by the dis +area the 1/2 accounts for the variation + + align:start position:0% +area the 1/2 accounts for the variation + + + align:start position:0% +area the 1/2 accounts for the variation +of B through the + + align:start position:0% +of B through the + + + align:start position:0% +of B through the +dis because Omega tow m is large the + + align:start position:0% +dis because Omega tow m is large the + + + align:start position:0% +dis because Omega tow m is large the +disc tends to act as a nearly perfect + + align:start position:0% +disc tends to act as a nearly perfect + + + align:start position:0% +disc tends to act as a nearly perfect +conductor current in the disc is then + + align:start position:0% +conductor current in the disc is then + + + align:start position:0% +conductor current in the disc is then +essentially equal to the field intensity + + align:start position:0% +essentially equal to the field intensity + + + align:start position:0% +essentially equal to the field intensity +in the + + align:start position:0% +in the + + + align:start position:0% +in the +Gap so this force is proportional to the + + align:start position:0% +Gap so this force is proportional to the + + + align:start position:0% +Gap so this force is proportional to the +force per unit area 12 mu + + align:start position:0% +force per unit area 12 mu + + + align:start position:0% +force per unit area 12 mu +h^2 times the area of the disc + + align:start position:0% +h^2 times the area of the disc + + + align:start position:0% +h^2 times the area of the disc +the additional 1/2 is because it is the + + align:start position:0% +the additional 1/2 is because it is the + + + align:start position:0% +the additional 1/2 is because it is the +time average of the square that is + + align:start position:0% + + + + align:start position:0% + +affected to evaluate this Force we guess + + align:start position:0% +affected to evaluate this Force we guess + + + align:start position:0% +affected to evaluate this Force we guess +that the field intensity in the Gap is + + align:start position:0% +that the field intensity in the Gap is + + + align:start position:0% +that the field intensity in the Gap is +perhaps two times that caused by the + + align:start position:0% +perhaps two times that caused by the + + + align:start position:0% +perhaps two times that caused by the +coil + + align:start position:0% +coil + + + align:start position:0% +coil +alone then the force Peaks at about 625 + + align:start position:0% +alone then the force Peaks at about 625 + + + align:start position:0% +alone then the force Peaks at about 625 +Newtons the dis weighs about 80 gr so + + align:start position:0% +Newtons the dis weighs about 80 gr so + + + align:start position:0% +Newtons the dis weighs about 80 gr so +that the force of gravity is a little + + align:start position:0% +that the force of gravity is a little + + + align:start position:0% +that the force of gravity is a little +less than 1 + + align:start position:0% +less than 1 + + + align:start position:0% +less than 1 +nton the magnetic force is about 800 + + align:start position:0% +nton the magnetic force is about 800 + + + align:start position:0% +nton the magnetic force is about 800 +times greater than that due to + + align:start position:0% +times greater than that due to + + + align:start position:0% +times greater than that due to +gravity so we expect + + align:start position:0% + + + + align:start position:0% + +liftoff but the force only acts for + + align:start position:0% +liftoff but the force only acts for + + + align:start position:0% +liftoff but the force only acts for +about a + + align:start position:0% +about a + + + align:start position:0% +about a +millisecond with what velocity will it + + align:start position:0% +millisecond with what velocity will it + + + align:start position:0% +millisecond with what velocity will it +leave the + + align:start position:0% + + + + align:start position:0% + +coil with aerodynamic drag ignored + + align:start position:0% +coil with aerodynamic drag ignored + + + align:start position:0% +coil with aerodynamic drag ignored +Newton's law states that this force is + + align:start position:0% +Newton's law states that this force is + + + align:start position:0% +Newton's law states that this force is +equal to the mass m of the dis times its + + align:start position:0% +equal to the mass m of the dis times its + + + align:start position:0% +equal to the mass m of the dis times its +acceleration ation the rate of change of + + align:start position:0% +acceleration ation the rate of change of + + + align:start position:0% +acceleration ation the rate of change of +its + + align:start position:0% +its + + + align:start position:0% +its +velocity here the force is represented + + align:start position:0% +velocity here the force is represented + + + align:start position:0% +velocity here the force is represented +by an + + align:start position:0% +by an + + + align:start position:0% +by an +Impulse having a duration T and A + + align:start position:0% +Impulse having a duration T and A + + + align:start position:0% +Impulse having a duration T and A +magnitude F Sub 0 equal to that just + + align:start position:0% +magnitude F Sub 0 equal to that just + + + align:start position:0% +magnitude F Sub 0 equal to that just +calculated integration of this + + align:start position:0% +calculated integration of this + + + align:start position:0% +calculated integration of this +expression from just before the button + + align:start position:0% +expression from just before the button + + + align:start position:0% +expression from just before the button +is pushed when the dis is at rest to + + align:start position:0% +is pushed when the dis is at rest to + + + align:start position:0% +is pushed when the dis is at rest to +just after shows that the initial + + align:start position:0% +just after shows that the initial + + + align:start position:0% +just after shows that the initial +velocity is this Force impulse divided + + align:start position:0% +velocity is this Force impulse divided + + + align:start position:0% +velocity is this Force impulse divided +by the mass of the dis + + align:start position:0% +by the mass of the dis + + + align:start position:0% +by the mass of the dis +for our numbers this velocity is 8 + + align:start position:0% +for our numbers this velocity is 8 + + + align:start position:0% +for our numbers this velocity is 8 +m/s or about 18 + + align:start position:0% +m/s or about 18 + + + align:start position:0% +m/s or about 18 +mph a good velocity for a + + align:start position:0% + + + + align:start position:0% + +bicycle uh perhaps we should estimate + + align:start position:0% +bicycle uh perhaps we should estimate + + + align:start position:0% +bicycle uh perhaps we should estimate +how high the disc will go before we push + + align:start position:0% +how high the disc will go before we push + + + align:start position:0% +how high the disc will go before we push +the button if the disc hurts the ceiling + + align:start position:0% +the button if the disc hurts the ceiling + + + align:start position:0% +the button if the disc hurts the ceiling +one of us might get fired + + align:start position:0% + + + + align:start position:0% + +the initial kinetic energy of the disc + + align:start position:0% +the initial kinetic energy of the disc + + + align:start position:0% +the initial kinetic energy of the disc +will be converted to potential form when + + align:start position:0% +will be converted to potential form when + + + align:start position:0% +will be converted to potential form when +it reaches its maximum height + + align:start position:0% +it reaches its maximum height + + + align:start position:0% +it reaches its maximum height +h g is the gravitational + + align:start position:0% +h g is the gravitational + + + align:start position:0% +h g is the gravitational +acceleration we predict a height of 3 + + align:start position:0% +acceleration we predict a height of 3 + + + align:start position:0% +acceleration we predict a height of 3 +m which is sufficiently small that we + + align:start position:0% +m which is sufficiently small that we + + + align:start position:0% +m which is sufficiently small that we +can perhaps responsibly push the + + align:start position:0% + + + + align:start position:0% + +button I'm melter and as you know that's + + align:start position:0% +button I'm melter and as you know that's + + + align:start position:0% +button I'm melter and as you know that's +Zan we brought along an illuminary here + + align:start position:0% +Zan we brought along an illuminary here + + + align:start position:0% +Zan we brought along an illuminary here +to push that button finally this is + + align:start position:0% +to push that button finally this is + + + align:start position:0% +to push that button finally this is +Professor Doc ederton and uh it's his + + align:start position:0% +Professor Doc ederton and uh it's his + + + align:start position:0% +Professor Doc ederton and uh it's his +machine what we've done of course is to + + align:start position:0% +machine what we've done of course is to + + + align:start position:0% +machine what we've done of course is to +show you this disc and now if uh doc you + + align:start position:0% +show you this disc and now if uh doc you + + + align:start position:0% +show you this disc and now if uh doc you +turn on your machine ready here we go + + align:start position:0% +turn on your machine ready here we go + + + align:start position:0% +turn on your machine ready here we go +I'm going to step out of this I'll turn + + align:start position:0% +I'm going to step out of this I'll turn + + + align:start position:0% +I'm going to step out of this I'll turn +on the main power let it come up to + + align:start position:0% + + + + align:start position:0% + +charge want do it again do you have a + + align:start position:0% +charge want do it again do you have a + + + align:start position:0% +charge want do it again do you have a +favorite one there well the everyone's a + + align:start position:0% +favorite one there well the everyone's a + + + align:start position:0% +favorite one there well the everyone's a +little different Mr try this one what do + + align:start position:0% +little different Mr try this one what do + + + align:start position:0% +little different Mr try this one what do +you + + align:start position:0% +you + + + align:start position:0% +you +say + + align:start position:0% + + + + align:start position:0% + +power little different ring to it little + + align:start position:0% +power little different ring to it little + + + align:start position:0% +power little different ring to it little +different ring now as I understand it + + align:start position:0% +different ring now as I understand it + + + align:start position:0% +different ring now as I understand it +this thing's got uh more capacitors in + + align:start position:0% +this thing's got uh more capacitors in + + + align:start position:0% +this thing's got uh more capacitors in +it maybe we get Zan to uh put a little + + align:start position:0% +it maybe we get Zan to uh put a little + + + align:start position:0% +it maybe we get Zan to uh put a little +more in there yeah you like to have it + + align:start position:0% +more in there yeah you like to have it + + + align:start position:0% +more in there yeah you like to have it +go a little the one of the reasons I + + align:start position:0% +go a little the one of the reasons I + + + align:start position:0% +go a little the one of the reasons I +brought this man along is that uh in + + align:start position:0% +brought this man along is that uh in + + + align:start position:0% +brought this man along is that uh in +fact he mainly paid for this building so + + align:start position:0% +fact he mainly paid for this building so + + + align:start position:0% +fact he mainly paid for this building so +you see we don't care too much if we + + align:start position:0% +you see we don't care too much if we + + + align:start position:0% +you see we don't care too much if we +hurt that + + align:start position:0% + + + + align:start position:0% + +ceiling it'd be nice to have an imprint + + align:start position:0% +ceiling it'd be nice to have an imprint + + + align:start position:0% +ceiling it'd be nice to have an imprint +up there wouldn't it right with you here + + align:start position:0% +up there wouldn't it right with you here + + + align:start position:0% +up there wouldn't it right with you here +I can say that okay let's see what + + align:start position:0% +I can say that okay let's see what + + + align:start position:0% +I can say that okay let's see what +happens this time well you got three + + align:start position:0% +happens this time well you got three + + + align:start position:0% +happens this time well you got three +capacitors on instead of one it should + + align:start position:0% +capacitors on instead of one it should + + + align:start position:0% +capacitors on instead of one it should +go a little + + align:start position:0% +go a little + + + align:start position:0% +go a little +higher one two three + + align:start position:0% +higher one two three + + + align:start position:0% +higher one two three +go missed me want to try our favorite + + align:start position:0% +go missed me want to try our favorite + + + align:start position:0% +go missed me want to try our favorite +let's try that + + align:start position:0% + + + + align:start position:0% + +one hey knocked a hole in the ceiling I + + align:start position:0% +one hey knocked a hole in the ceiling I + + + align:start position:0% +one hey knocked a hole in the ceiling I +can see you enjoy that huh all right + + align:start position:0% +can see you enjoy that huh all right + + + align:start position:0% +can see you enjoy that huh all right +thank you very much sir now actually + + align:start position:0% +thank you very much sir now actually + + + align:start position:0% +thank you very much sir now actually +you're getting the impression this is + + align:start position:0% +you're getting the impression this is + + + align:start position:0% +you're getting the impression this is +all just fun in games if you look in + + align:start position:0% +all just fun in games if you look in + + + align:start position:0% +all just fun in games if you look in +inside this box you'll find a number on + + align:start position:0% +inside this box you'll find a number on + + + align:start position:0% +inside this box you'll find a number on +it + + align:start position:0% +it + + + align:start position:0% +it +1960 and uh Circa sometime like that + + align:start position:0% +1960 and uh Circa sometime like that + + + align:start position:0% +1960 and uh Circa sometime like that +this man was busy sounding the bottom of + + align:start position:0% +this man was busy sounding the bottom of + + + align:start position:0% +this man was busy sounding the bottom of +the ocean with this device in fact a few + + align:start position:0% +the ocean with this device in fact a few + + + align:start position:0% +the ocean with this device in fact a few +minutes ago he showed me a book that's + + align:start position:0% +minutes ago he showed me a book that's + + + align:start position:0% +minutes ago he showed me a book that's +out it's uh what sonar images by Harold + + align:start position:0% +out it's uh what sonar images by Harold + + + align:start position:0% +out it's uh what sonar images by Harold +e ederton and uh we were just picking + + align:start position:0% +e ederton and uh we were just picking + + + align:start position:0% +e ederton and uh we were just picking +out something in here that might give + + align:start position:0% +out something in here that might give + + + align:start position:0% +out something in here that might give +you an idea of the kind of um of serious + + align:start position:0% +you an idea of the kind of um of serious + + + align:start position:0% +you an idea of the kind of um of serious +business that a boomer like this or + + align:start position:0% +business that a boomer like this or + + + align:start position:0% +business that a boomer like this or +other sonar devices uh can carry out + + align:start position:0% +other sonar devices uh can carry out + + + align:start position:0% +other sonar devices uh can carry out +maybe doc you could try and explain this + + align:start position:0% +maybe doc you could try and explain this + + + align:start position:0% +maybe doc you could try and explain this +to us this this is the surface of the + + align:start position:0% +to us this this is the surface of the + + + align:start position:0% +to us this this is the surface of the +ocean and then the sound goes down and + + align:start position:0% +ocean and then the sound goes down and + + + align:start position:0% +ocean and then the sound goes down and +reflects off the bottom this the bottom + + align:start position:0% +reflects off the bottom this the bottom + + + align:start position:0% +reflects off the bottom this the bottom +of the ocean and with these powerful + + align:start position:0% +of the ocean and with these powerful + + + align:start position:0% +of the ocean and with these powerful +sources where you get enough energy + + align:start position:0% +sources where you get enough energy + + + align:start position:0% +sources where you get enough energy +it'll go through and gives you sub + + align:start position:0% +it'll go through and gives you sub + + + align:start position:0% +it'll go through and gives you sub +bottoms that are down below that are + + align:start position:0% +bottoms that are down below that are + + + align:start position:0% +bottoms that are down below that are +tremendous interest of the geologists + + align:start position:0% +tremendous interest of the geologists + + + align:start position:0% +tremendous interest of the geologists +they all want to know where these sub + + align:start position:0% +they all want to know where these sub + + + align:start position:0% +they all want to know where these sub +bottoms are and as I understand it if we + + align:start position:0% +bottoms are and as I understand it if we + + + align:start position:0% +bottoms are and as I understand it if we +have a big enough disc we make a a low + + align:start position:0% +have a big enough disc we make a a low + + + align:start position:0% +have a big enough disc we make a a low +enough frequency energy that it does + + align:start position:0% +enough frequency energy that it does + + + align:start position:0% +enough frequency energy that it does +penetrate that substrate yep so you gave + + align:start position:0% +penetrate that substrate yep so you gave + + + align:start position:0% +penetrate that substrate yep so you gave +me a little bigger disc here huh yeah + + align:start position:0% +me a little bigger disc here huh yeah + + + align:start position:0% +me a little bigger disc here huh yeah +let me get it out for + + align:start position:0% + + + + align:start position:0% + +us and I think you realize Jim this now + + align:start position:0% +us and I think you realize Jim this now + + + align:start position:0% +us and I think you realize Jim this now +there's a disc huh yeah this coil isn't + + align:start position:0% +there's a disc huh yeah this coil isn't + + + align:start position:0% +there's a disc huh yeah this coil isn't +as big as the coil would be as big as + + align:start position:0% +as big as the coil would be as big as + + + align:start position:0% +as big as the coil would be as big as +this and we'd have maybe 10 times as + + align:start position:0% +this and we'd have maybe 10 times as + + + align:start position:0% +this and we'd have maybe 10 times as +many capacitors on it + + align:start position:0% +many capacitors on it + + + align:start position:0% +many capacitors on it +so yes what we got a small one on there + + align:start position:0% +so yes what we got a small one on there + + + align:start position:0% +so yes what we got a small one on there +now I was trying to get him to bring us + + align:start position:0% +now I was trying to get him to bring us + + + align:start position:0% +now I was trying to get him to bring us +over a disc that has pits in it from the + + align:start position:0% +over a disc that has pits in it from the + + + align:start position:0% +over a disc that has pits in it from the +cavitation unfortunately he's thrown it + + align:start position:0% +cavitation unfortunately he's thrown it + + + align:start position:0% +cavitation unfortunately he's thrown it +out are we going to hit it with that + + align:start position:0% +out are we going to hit it with that + + + align:start position:0% +out are we going to hit it with that +maximum capacity yeah well he's got them + + align:start position:0% +maximum capacity yeah well he's got them + + + align:start position:0% +maximum capacity yeah well he's got them +all in right back off little I don't + + align:start position:0% +all in right back off little I don't + + + align:start position:0% +all in right back off little I don't +think it'll go very high but I'll back + + align:start position:0% +think it'll go very high but I'll back + + + align:start position:0% +think it'll go very high but I'll back +off it'll make a noise I think it'll + + align:start position:0% +off it'll make a noise I think it'll + + + align:start position:0% +off it'll make a noise I think it'll +make a noise that's the point you ready + + align:start position:0% +make a noise that's the point you ready + + + align:start position:0% +make a noise that's the point you ready +go that's worth trying again + + align:start position:0% +go that's worth trying again + + + align:start position:0% +go that's worth trying again +yeah it jumps up about a/ inch if you + + align:start position:0% +yeah it jumps up about a/ inch if you + + + align:start position:0% +yeah it jumps up about a/ inch if you +put enough energy you can throw the + + align:start position:0% +put enough energy you can throw the + + + align:start position:0% +put enough energy you can throw the +thing clear clear over doc thank you + + align:start position:0% +thing clear clear over doc thank you + + + align:start position:0% +thing clear clear over doc thank you +very much for being here thank + + align:start position:0% +very much for being here thank + + + align:start position:0% +very much for being here thank +you still ringing h \ No newline at end of file diff --git a/MT3LjjdODHA.txt b/MT3LjjdODHA.txt new file mode 100644 index 0000000000000000000000000000000000000000..3d410a1c6d7106892d7ab6b61c3ec27283f04191 --- /dev/null +++ b/MT3LjjdODHA.txt @@ -0,0 +1,3099 @@ +align:start position:0% + +me I would say that most of even + + align:start position:0% +me I would say that most of even + + + align:start position:0% +me I would say that most of even +contemporary views about cre are still + + align:start position:0% +contemporary views about cre are still + + + align:start position:0% +contemporary views about cre are still +driven by the same racism that + + align:start position:0% +driven by the same racism that + + + align:start position:0% +driven by the same racism that +characterize slavery and then they they + + align:start position:0% +characterize slavery and then they they + + + align:start position:0% +characterize slavery and then they they +they conclude and I want to take that + + align:start position:0% +they conclude and I want to take that + + + align:start position:0% +they conclude and I want to take that +conclusion very seriously that that + + align:start position:0% +conclusion very seriously that that + + + align:start position:0% +conclusion very seriously that that +although we might use a label Creole but + + align:start position:0% +although we might use a label Creole but + + + align:start position:0% +although we might use a label Creole but +that label doesn't mean that it's that + + align:start position:0% +that label doesn't mean that it's that + + + align:start position:0% +that label doesn't mean that it's that +have a linguistic structural class class + + align:start position:0% +have a linguistic structural class class + + + align:start position:0% +have a linguistic structural class class +of cre languages the term creal is just + + align:start position:0% +of cre languages the term creal is just + + + align:start position:0% +of cre languages the term creal is just +a historical term that applies to this + + align:start position:0% +a historical term that applies to this + + + align:start position:0% +a historical term that applies to this +particular group of languages um but not + + align:start position:0% +particular group of languages um but not + + + align:start position:0% +particular group of languages um but not +isn't isn't refer to special + + align:start position:0% +isn't isn't refer to special + + + align:start position:0% +isn't isn't refer to special +developmental or special structural + + align:start position:0% +developmental or special structural + + + align:start position:0% +developmental or special structural +patterns you know they're just they're + + align:start position:0% +patterns you know they're just they're + + + align:start position:0% +patterns you know they're just they're +just just a language that's what the cre + + align:start position:0% +just just a language that's what the cre + + + align:start position:0% +just just a language that's what the cre +is okay um so but then you know what we + + align:start position:0% +is okay um so but then you know what we + + + align:start position:0% +is okay um so but then you know what we +have to ask is you know where do we go + + align:start position:0% +have to ask is you know where do we go + + + align:start position:0% +have to ask is you know where do we go +from here so we know of that but then + + align:start position:0% +from here so we know of that but then + + + align:start position:0% +from here so we know of that but then +what was the issue there um and in fact + + align:start position:0% +what was the issue there um and in fact + + + align:start position:0% +what was the issue there um and in fact +we can do one thing that and this is + + align:start position:0% +we can do one thing that and this is + + + align:start position:0% +we can do one thing that and this is +from mu work so this is this I like this + + align:start position:0% +from mu work so this is this I like this + + + align:start position:0% +from mu work so this is this I like this +map because what it shows is what we + + align:start position:0% +map because what it shows is what we + + + align:start position:0% +map because what it shows is what we +discussed earlier right the fact that if + + align:start position:0% +discussed earlier right the fact that if + + + align:start position:0% +discussed earlier right the fact that if +you really look at CRS without biases + + align:start position:0% +you really look at CRS without biases + + + align:start position:0% +you really look at CRS without biases +and you think of the development and you + + align:start position:0% +and you think of the development and you + + + align:start position:0% +and you think of the development and you +go back in time and you think of the + + align:start position:0% +go back in time and you think of the + + + align:start position:0% +go back in time and you think of the +development of of romance languages + + align:start position:0% +development of of romance languages + + + align:start position:0% +development of of romance languages +right so this is the way romance evolve + + align:start position:0% +right so this is the way romance evolve + + + align:start position:0% +right so this is the way romance evolve +so you had Latin conquerors going from + + align:start position:0% +so you had Latin conquerors going from + + + align:start position:0% +so you had Latin conquerors going from +Rome into go Iberia Etc and that's how + + align:start position:0% +Rome into go Iberia Etc and that's how + + + align:start position:0% +Rome into go Iberia Etc and that's how +the romance languages were created by + + align:start position:0% +the romance languages were created by + + + align:start position:0% +the romance languages were created by +through conquest and and contact of + + align:start position:0% +through conquest and and contact of + + + align:start position:0% +through conquest and and contact of +populations and in the same way if you + + align:start position:0% +populations and in the same way if you + + + align:start position:0% +populations and in the same way if you +look at you know what happened to French + + align:start position:0% +look at you know what happened to French + + + align:start position:0% +look at you know what happened to French +when French went to North America the + + align:start position:0% +when French went to North America the + + + align:start position:0% +when French went to North America the +Caribbean Africa all the way to Asia + + align:start position:0% +Caribbean Africa all the way to Asia + + + align:start position:0% +Caribbean Africa all the way to Asia +that's also how Crees were created you + + align:start position:0% +that's also how Crees were created you + + + align:start position:0% +that's also how Crees were created you +know you got hisan cre M Creole macius + + align:start position:0% +know you got hisan cre M Creole macius + + + align:start position:0% +know you got hisan cre M Creole macius +Creole Cel Creole and and this is where + + align:start position:0% +Creole Cel Creole and and this is where + + + align:start position:0% +Creole Cel Creole and and this is where +you get the kopon right um alongside Fon + + align:start position:0% +you get the kopon right um alongside Fon + + + align:start position:0% +you get the kopon right um alongside Fon +of course but the claim I've made so far + + align:start position:0% +of course but the claim I've made so far + + + align:start position:0% +of course but the claim I've made so far +is that you have similar patterns not + + align:start position:0% +is that you have similar patterns not + + + align:start position:0% +is that you have similar patterns not +only in terms of language contact but + + align:start position:0% +only in terms of language contact but + + + align:start position:0% +only in terms of language contact but +also in terms of structural development + + align:start position:0% +also in terms of structural development + + + align:start position:0% +also in terms of structural development +um so from that perspective again there + + align:start position:0% +um so from that perspective again there + + + align:start position:0% +um so from that perspective again there +cannot be there need not be this this + + align:start position:0% +cannot be there need not be this this + + + align:start position:0% +cannot be there need not be this this +divide this fundamental divide that + + align:start position:0% +divide this fundamental divide that + + + align:start position:0% +divide this fundamental divide that +language often draw between language + + align:start position:0% +language often draw between language + + + align:start position:0% +language often draw between language +change as in the history of French and + + align:start position:0% +change as in the history of French and + + + align:start position:0% +change as in the history of French and +then cre formation as in the hist paent + + align:start position:0% +then cre formation as in the hist paent + + + align:start position:0% +then cre formation as in the hist paent +Creole you see um so earlier we talked + + align:start position:0% +Creole you see um so earlier we talked + + + align:start position:0% +Creole you see um so earlier we talked +about these um + + align:start position:0% +about these um + + + align:start position:0% +about these um +these myths uh uh about V cre so now + + align:start position:0% +these myths uh uh about V cre so now + + + align:start position:0% +these myths uh uh about V cre so now +what we could ask is um and so now this + + align:start position:0% +what we could ask is um and so now this + + + align:start position:0% +what we could ask is um and so now this +is just in case you want to you want to + + align:start position:0% +is just in case you want to you want to + + + align:start position:0% +is just in case you want to you want to +read more about it so you can go to my + + align:start position:0% +read more about it so you can go to my + + + align:start position:0% +read more about it so you can go to my +website and you you'll find lots and + + align:start position:0% +website and you you'll find lots and + + + align:start position:0% +website and you you'll find lots and +lots of arguments against this um this + + align:start position:0% +lots of arguments against this um this + + + align:start position:0% +lots of arguments against this um this +idea that you have this this cycle and + + align:start position:0% +idea that you have this this cycle and + + + align:start position:0% +idea that you have this this cycle and +then but what we have to now and here + + align:start position:0% +then but what we have to now and here + + + align:start position:0% +then but what we have to now and here +I'm going to be using some of the SL + + align:start position:0% +I'm going to be using some of the SL + + + align:start position:0% +I'm going to be using some of the SL +that I showed at the at the UN last week + + align:start position:0% +that I showed at the at the UN last week + + + align:start position:0% +that I showed at the at the UN last week +so because what we want to ask + + align:start position:0% +so because what we want to ask + + + align:start position:0% +so because what we want to ask +connecting to the issues of identity and + + align:start position:0% +connecting to the issues of identity and + + + align:start position:0% +connecting to the issues of identity and +education that were touched on uh by + + align:start position:0% +education that were touched on uh by + + + align:start position:0% +education that were touched on uh by +Karen and and Rachel is you know why why + + align:start position:0% +Karen and and Rachel is you know why why + + + align:start position:0% +Karen and and Rachel is you know why why +do these meats endure and then actually + + align:start position:0% +do these meats endure and then actually + + + align:start position:0% +do these meats endure and then actually +now this I can go quickly actually + + align:start position:0% +now this I can go quickly actually + + + align:start position:0% +now this I can go quickly actually +because you've You' you've seen all of + + align:start position:0% +because you've You' you've seen all of + + + align:start position:0% +because you've You' you've seen all of +these before right but I just wanted to + + align:start position:0% +these before right but I just wanted to + + + align:start position:0% +these before right but I just wanted to +to to bring them back very quickly you + + align:start position:0% +to to bring them back very quickly you + + + align:start position:0% +to to bring them back very quickly you +know so now this is again this is you + + align:start position:0% +know so now this is again this is you + + + align:start position:0% +know so now this is again this is you +find this meth in you know very well + + align:start position:0% +find this meth in you know very well + + + align:start position:0% +find this meth in you know very well +read popular newspapers magazines like + + align:start position:0% +read popular newspapers magazines like + + + align:start position:0% +read popular newspapers magazines like +Newsweek the New York Times um riters + + align:start position:0% +Newsweek the New York Times um riters + + + align:start position:0% +Newsweek the New York Times um riters +even the New Yorker you know and all of + + align:start position:0% +even the New Yorker you know and all of + + + align:start position:0% +even the New Yorker you know and all of +these that something in common that we + + align:start position:0% +these that something in common that we + + + align:start position:0% +these that something in common that we +saw earlier right that now should be too + + align:start position:0% +saw earlier right that now should be too + + + align:start position:0% +saw earlier right that now should be too +familiar which is you know cre or French + + align:start position:0% +familiar which is you know cre or French + + + align:start position:0% +familiar which is you know cre or French +pwa broken French you know they're like + + align:start position:0% +pwa broken French you know they're like + + + align:start position:0% +pwa broken French you know they're like +primitive languages this is uh or this + + align:start position:0% +primitive languages this is uh or this + + + align:start position:0% +primitive languages this is uh or this +one is the most poetic and I like this + + align:start position:0% +one is the most poetic and I like this + + + align:start position:0% +one is the most poetic and I like this +one because it makes me into a special + + align:start position:0% +one because it makes me into a special + + + align:start position:0% +one because it makes me into a special +specimen of of humanity right because + + align:start position:0% +specimen of of humanity right because + + + align:start position:0% +specimen of of humanity right because +really that's what it means right that + + align:start position:0% +really that's what it means right that + + + align:start position:0% +really that's what it means right that +means that you know as I like to say + + align:start position:0% +means that you know as I like to say + + + align:start position:0% +means that you know as I like to say +when I give this talk in public when I + + align:start position:0% +when I give this talk in public when I + + + align:start position:0% +when I give this talk in public when I +when I switch from speaking English to + + align:start position:0% +when I switch from speaking English to + + + align:start position:0% +when I switch from speaking English to +speaking cre oh I go from being a modern + + align:start position:0% +speaking cre oh I go from being a modern + + + align:start position:0% +speaking cre oh I go from being a modern +human to being a primitive human because + + align:start position:0% +human to being a primitive human because + + + align:start position:0% +human to being a primitive human because +I can all of a sudden on my tongue you + + align:start position:0% +I can all of a sudden on my tongue you + + + align:start position:0% +I can all of a sudden on my tongue you +know I get to pronounce this linguistic + + align:start position:0% +know I get to pronounce this linguistic + + + align:start position:0% +know I get to pronounce this linguistic +fossils which are the equivalent of the + + align:start position:0% +fossils which are the equivalent of the + + + align:start position:0% +fossils which are the equivalent of the +calabos towin I this is this is + + align:start position:0% +calabos towin I this is this is + + + align:start position:0% +calabos towin I this is this is +spectacular this is a spectacular claim + + align:start position:0% +spectacular this is a spectacular claim + + + align:start position:0% +spectacular this is a spectacular claim +right I mean and this is Newsweek you + + align:start position:0% +right I mean and this is Newsweek you + + + align:start position:0% +right I mean and this is Newsweek you +know this is the New York Times but is + + align:start position:0% +know this is the New York Times but is + + + align:start position:0% +know this is the New York Times but is +to show you how acceptable these claims + + align:start position:0% +to show you how acceptable these claims + + + align:start position:0% +to show you how acceptable these claims +are right but then you know again to + + align:start position:0% +are right but then you know again to + + + align:start position:0% +are right but then you know again to +wrap up from what we discussed earlier + + align:start position:0% +wrap up from what we discussed earlier + + + align:start position:0% +wrap up from what we discussed earlier +uh this is in very much in Sy with uh + + align:start position:0% +uh this is in very much in Sy with uh + + + align:start position:0% +uh this is in very much in Sy with uh +with Michelle Hof too right uh now this + + align:start position:0% +with Michelle Hof too right uh now this + + + align:start position:0% +with Michelle Hof too right uh now this +is going back to the early part of this + + align:start position:0% +is going back to the early part of this + + + align:start position:0% +is going back to the early part of this +of this class which where we you know + + align:start position:0% +of this class which where we you know + + + align:start position:0% +of this class which where we you know +looking at history so what we see is + + align:start position:0% +looking at history so what we see is + + + align:start position:0% +looking at history so what we see is +that the same way that Creos have been + + align:start position:0% +that the same way that Creos have been + + + align:start position:0% +that the same way that Creos have been +silenced the fact that cre are normal + + align:start position:0% +silenced the fact that cre are normal + + + align:start position:0% +silenced the fact that cre are normal +languages that has been silenced is also + + align:start position:0% +languages that has been silenced is also + + + align:start position:0% +languages that has been silenced is also +the same way that um Asian history has + + align:start position:0% +the same way that um Asian history has + + + align:start position:0% +the same way that um Asian history has +been silenced for the same reason + + align:start position:0% +been silenced for the same reason + + + align:start position:0% +been silenced for the same reason +because how many of you before this + + align:start position:0% +because how many of you before this + + + align:start position:0% +because how many of you before this +class knew about Asian + + align:start position:0% +class knew about Asian + + + align:start position:0% +class knew about Asian +history right you because you have a + + align:start position:0% +history right you because you have a + + + align:start position:0% +history right you because you have a +Asian boyfriend right + + align:start position:0% +Asian boyfriend right + + + align:start position:0% +Asian boyfriend right +yeah but but most of us you know and + + align:start position:0% +yeah but but most of us you know and + + + align:start position:0% +yeah but but most of us you know and +when I asked that question you know even + + align:start position:0% +when I asked that question you know even + + + align:start position:0% +when I asked that question you know even +in my in big classes like you know 24900 + + align:start position:0% +in my in big classes like you know 24900 + + + align:start position:0% +in my in big classes like you know 24900 +with hundred of students I get maybe one + + align:start position:0% +with hundred of students I get maybe one + + + align:start position:0% +with hundred of students I get maybe one +or two people to know that thean + + align:start position:0% +or two people to know that thean + + + align:start position:0% +or two people to know that thean +Revolution was even more dramatic in + + align:start position:0% +Revolution was even more dramatic in + + + align:start position:0% +Revolution was even more dramatic in +terms of its claims than both the French + + align:start position:0% +terms of its claims than both the French + + + align:start position:0% +terms of its claims than both the French +and the American Revolutions know it was + + align:start position:0% +and the American Revolutions know it was + + + align:start position:0% +and the American Revolutions know it was +the only one in the in the 18th century + + align:start position:0% +the only one in the in the 18th century + + + align:start position:0% +the only one in the in the 18th century +to Proclaim Liberty and equality for all + + align:start position:0% +to Proclaim Liberty and equality for all + + + align:start position:0% +to Proclaim Liberty and equality for all +the only one the French one the friend + + align:start position:0% +the only one the French one the friend + + + align:start position:0% +the only one the French one the friend +still had slaves the American one + + align:start position:0% +still had slaves the American one + + + align:start position:0% +still had slaves the American one +Jefferson Med all these guys they still + + align:start position:0% +Jefferson Med all these guys they still + + + align:start position:0% +Jefferson Med all these guys they still +had slaves know Haiti was the only + + align:start position:0% +had slaves know Haiti was the only + + + align:start position:0% +had slaves know Haiti was the only +Revolution where there was this claim + + align:start position:0% +Revolution where there was this claim + + + align:start position:0% +Revolution where there was this claim +for uh Liberty for all but you know this + + align:start position:0% +for uh Liberty for all but you know this + + + align:start position:0% +for uh Liberty for all but you know this +is from Toyo that you know as Haiti was + + align:start position:0% +is from Toyo that you know as Haiti was + + + align:start position:0% +is from Toyo that you know as Haiti was +entering history you know it was being + + align:start position:0% +entering history you know it was being + + + align:start position:0% +entering history you know it was being +written about by people who could not + + align:start position:0% +written about by people who could not + + + align:start position:0% +written about by people who could not +conceive of the Africans as equals to + + align:start position:0% +conceive of the Africans as equals to + + + align:start position:0% +conceive of the Africans as equals to +the Europeans right so so according to + + align:start position:0% +the Europeans right so so according to + + + align:start position:0% +the Europeans right so so according to +Toyo those 18th century Scholars uh they + + align:start position:0% +Toyo those 18th century Scholars uh they + + + align:start position:0% +Toyo those 18th century Scholars uh they +could only read the news news only with + + align:start position:0% +could only read the news news only with + + + align:start position:0% +could only read the news news only with +the ready made lenses and it meant that + + align:start position:0% +the ready made lenses and it meant that + + + align:start position:0% +the ready made lenses and it meant that +African Liberation the fact that an + + align:start position:0% +African Liberation the fact that an + + + align:start position:0% +African Liberation the fact that an +African Army could win over Napoleon + + align:start position:0% +African Army could win over Napoleon + + + align:start position:0% +African Army could win over Napoleon +they couldn't process that you know it + + align:start position:0% +they couldn't process that you know it + + + align:start position:0% +they couldn't process that you know it +was incompatible with the idea of a + + align:start position:0% +was incompatible with the idea of a + + + align:start position:0% +was incompatible with the idea of a +slave revolution and the same way for + + align:start position:0% +slave revolution and the same way for + + + align:start position:0% +slave revolution and the same way for +language so the same Scholars looking at + + align:start position:0% +language so the same Scholars looking at + + + align:start position:0% +language so the same Scholars looking at +hies Revolution they also looking at at + + align:start position:0% +hies Revolution they also looking at at + + + align:start position:0% +hies Revolution they also looking at at +cre language and they couldn't imagine + + align:start position:0% +cre language and they couldn't imagine + + + align:start position:0% +cre language and they couldn't imagine +for them it was impossible that cre + + align:start position:0% +for them it was impossible that cre + + + align:start position:0% +for them it was impossible that cre +would be normal languages right so so + + align:start position:0% +would be normal languages right so so + + + align:start position:0% +would be normal languages right so so +you can just pass on that um so so the + + align:start position:0% +you can just pass on that um so so the + + + align:start position:0% +you can just pass on that um so so the +so this is very familiar uh so this is + + align:start position:0% +so this is very familiar uh so this is + + + align:start position:0% +so this is very familiar uh so this is +the root of all these myth so the root + + align:start position:0% +the root of all these myth so the root + + + align:start position:0% +the root of all these myth so the root +of these myth is basically in the idea + + align:start position:0% +of these myth is basically in the idea + + + align:start position:0% +of these myth is basically in the idea +that um the Africans were lesser and + + align:start position:0% +that um the Africans were lesser and + + + align:start position:0% +that um the Africans were lesser and +whatever this they could produce as + + align:start position:0% +whatever this they could produce as + + + align:start position:0% +whatever this they could produce as +language had to be lesser therefore they + + align:start position:0% +language had to be lesser therefore they + + + align:start position:0% +language had to be lesser therefore they +could not be part of the same kind of um + + align:start position:0% +could not be part of the same kind of um + + + align:start position:0% +could not be part of the same kind of um +Theory as um normal language change as + + align:start position:0% +Theory as um normal language change as + + + align:start position:0% +Theory as um normal language change as +the of French so but again I can say you + + align:start position:0% +the of French so but again I can say you + + + align:start position:0% +the of French so but again I can say you +know it's the economist to meaning that + + align:start position:0% +know it's the economist to meaning that + + + align:start position:0% +know it's the economist to meaning that +you know the driving in fact this is not + + align:start position:0% +you know the driving in fact this is not + + + align:start position:0% +you know the driving in fact this is not +clear you know so yesterday actually so + + align:start position:0% +clear you know so yesterday actually so + + + align:start position:0% +clear you know so yesterday actually so +n chumsky was in Black matters and I + + align:start position:0% +n chumsky was in Black matters and I + + + align:start position:0% +n chumsky was in Black matters and I +asked that question about um you know + + align:start position:0% +asked that question about um you know + + + align:start position:0% +asked that question about um you know +what what came first the economy you + + align:start position:0% +what what came first the economy you + + + align:start position:0% +what what came first the economy you +know Empire or or racism right because + + align:start position:0% +know Empire or or racism right because + + + align:start position:0% +know Empire or or racism right because +one could say that racism is a result of + + align:start position:0% +one could say that racism is a result of + + + align:start position:0% +one could say that racism is a result of +Empire you know if you want to create if + + align:start position:0% +Empire you know if you want to create if + + + align:start position:0% +Empire you know if you want to create if +you want to make the Africans as B of + + align:start position:0% +you want to make the Africans as B of + + + align:start position:0% +you want to make the Africans as B of +Labor in order to produce wealth then + + align:start position:0% +Labor in order to produce wealth then + + + align:start position:0% +Labor in order to produce wealth then +you're going to deman know the color the + + align:start position:0% +you're going to deman know the color the + + + align:start position:0% +you're going to deman know the color the +culture the language or is it was Rec in + + align:start position:0% +culture the language or is it was Rec in + + + align:start position:0% +culture the language or is it was Rec in +there before and therefore made it okay + + align:start position:0% +there before and therefore made it okay + + + align:start position:0% +there before and therefore made it okay +to make them into space that's that's a + + align:start position:0% +to make them into space that's that's a + + + align:start position:0% +to make them into space that's that's a +hard question to + + align:start position:0% +hard question to + + + align:start position:0% +hard question to +answer that's that's it's hard to know + + align:start position:0% +answer that's that's it's hard to know + + + align:start position:0% +answer that's that's it's hard to know +maybe maybe the two as chumsky puts it + + align:start position:0% +maybe maybe the two as chumsky puts it + + + align:start position:0% +maybe maybe the two as chumsky puts it +the two kind of reinforce each other you + + align:start position:0% +the two kind of reinforce each other you + + + align:start position:0% +the two kind of reinforce each other you +see in the case of hati though I mean we + + align:start position:0% +see in the case of hati though I mean we + + + align:start position:0% +see in the case of hati though I mean we +have all these documents that show that + + align:start position:0% +have all these documents that show that + + + align:start position:0% +have all these documents that show that +um that uh that clearly there was this + + align:start position:0% +um that uh that clearly there was this + + + align:start position:0% +um that uh that clearly there was this +one of the driving force behind the + + align:start position:0% +one of the driving force behind the + + + align:start position:0% +one of the driving force behind the +black code which was a code that would + + align:start position:0% +black code which was a code that would + + + align:start position:0% +black code which was a code that would +you know to regulate the the the the + + align:start position:0% +you know to regulate the the the the + + + align:start position:0% +you know to regulate the the the the +slaves in in the Caribbean you + + align:start position:0% +slaves in in the Caribbean you + + + align:start position:0% +slaves in in the Caribbean you +know the driving force behind it was + + align:start position:0% +know the driving force behind it was + + + align:start position:0% +know the driving force behind it was +economics right um you know something + + align:start position:0% +economics right um you know something + + + align:start position:0% +economics right um you know something +like that right + + align:start position:0% +like that right + + + align:start position:0% +like that right +so uh so theya that you know the cre + + align:start position:0% +so uh so theya that you know the cre + + + align:start position:0% +so uh so theya that you know the cre +blacks are superior because they are in + + align:start position:0% +blacks are superior because they are in + + + align:start position:0% +blacks are superior because they are in +the company of whites you know something + + align:start position:0% +the company of whites you know something + + + align:start position:0% +the company of whites you know something +like that you know so for all the task + + align:start position:0% +like that you know so for all the task + + + align:start position:0% +like that you know so for all the task +is the cre slaves that are preferred and + + align:start position:0% +is the cre slaves that are preferred and + + + align:start position:0% +is the cre slaves that are preferred and +here the that know the cre slaves are + + align:start position:0% +here the that know the cre slaves are + + + align:start position:0% +here the that know the cre slaves are +those who are born in the Caribbean uh + + align:start position:0% +those who are born in the Caribbean uh + + + align:start position:0% +those who are born in the Caribbean uh +they they have African ancestry but they + + align:start position:0% +they they have African ancestry but they + + + align:start position:0% +they they have African ancestry but they +BN in the Caribbean and and and they + + align:start position:0% +BN in the Caribbean and and and they + + + align:start position:0% +BN in the Caribbean and and and they +have more worth why because um they are + + align:start position:0% +have more worth why because um they are + + + align:start position:0% +have more worth why because um they are +being uh assimilated into European + + align:start position:0% +being uh assimilated into European + + + align:start position:0% +being uh assimilated into European +culture talking about assimilation so + + align:start position:0% +culture talking about assimilation so + + + align:start position:0% +culture talking about assimilation so +here assimilation comes with a benefit + + align:start position:0% +here assimilation comes with a benefit + + + align:start position:0% +here assimilation comes with a benefit +as you being assimilated you acquire and + + align:start position:0% +as you being assimilated you acquire and + + + align:start position:0% +as you being assimilated you acquire and +actually this guy this is the same guy + + align:start position:0% +actually this guy this is the same guy + + + align:start position:0% +actually this guy this is the same guy +actually who came up with this 128 P of + + align:start position:0% +actually who came up with this 128 P of + + + align:start position:0% +actually who came up with this 128 P of +blood right you could compute qualities + + align:start position:0% +blood right you could compute qualities + + + align:start position:0% +blood right you could compute qualities +of of different mixes based on the + + align:start position:0% +of of different mixes based on the + + + align:start position:0% +of of different mixes based on the +quanta of blood white blood versus black + + align:start position:0% +quanta of blood white blood versus black + + + align:start position:0% +quanta of blood white blood versus black +blood he also had quanta in terms of + + align:start position:0% +blood he also had quanta in terms of + + + align:start position:0% +blood he also had quanta in terms of +uh the worth of cre slaves versus those + + align:start position:0% +uh the worth of cre slaves versus those + + + align:start position:0% +uh the worth of cre slaves versus those +of African slaves a quarter more um to + + align:start position:0% +of African slaves a quarter more um to + + + align:start position:0% +of African slaves a quarter more um to +imagine um and of course you know the + + align:start position:0% +imagine um and of course you know the + + + align:start position:0% +imagine um and of course you know the +idea that you know what made them better + + align:start position:0% +idea that you know what made them better + + + align:start position:0% +idea that you know what made them better +is because they had been assimilated or + + align:start position:0% +is because they had been assimilated or + + + align:start position:0% +is because they had been assimilated or +in this case he use the poetic term + + align:start position:0% +in this case he use the poetic term + + + align:start position:0% +in this case he use the poetic term +embellished that the Domesticity meaning + + align:start position:0% +embellished that the Domesticity meaning + + + align:start position:0% +embellished that the Domesticity meaning +slavery by whites would embellish the + + align:start position:0% +slavery by whites would embellish the + + + align:start position:0% +slavery by whites would embellish the +black species right um + + align:start position:0% +black species right um + + + align:start position:0% +black species right um +so this is some of the background behind + + align:start position:0% +so this is some of the background behind + + + align:start position:0% +so this is some of the background behind +all these claims about cre languages um + + align:start position:0% +all these claims about cre languages um + + + align:start position:0% +all these claims about cre languages um +but of course the other part of the + + align:start position:0% +but of course the other part of the + + + align:start position:0% +but of course the other part of the +background that you know is the fact + + align:start position:0% +background that you know is the fact + + + align:start position:0% +background that you know is the fact +that um there was this revolution that + + align:start position:0% +that um there was this revolution that + + + align:start position:0% +that um there was this revolution that +had to be silenced this is the book that + + align:start position:0% +had to be silenced this is the book that + + + align:start position:0% +had to be silenced this is the book that +you read uh as you put of it that you + + align:start position:0% +you read uh as you put of it that you + + + align:start position:0% +you read uh as you put of it that you +read uh about silencing the past and and + + align:start position:0% +read uh about silencing the past and and + + + align:start position:0% +read uh about silencing the past and and +so what I'm driving at here is that um + + align:start position:0% +so what I'm driving at here is that um + + + align:start position:0% +so what I'm driving at here is that um +all this together you + + align:start position:0% +all this together you + + + align:start position:0% +all this together you +know created the roots of um this View + + align:start position:0% +know created the roots of um this View + + + align:start position:0% +know created the roots of um this View +use that cre are special and and again + + align:start position:0% +use that cre are special and and again + + + align:start position:0% +use that cre are special and and again +just for good measure I want to stress + + align:start position:0% +just for good measure I want to stress + + + align:start position:0% +just for good measure I want to stress +again um espcially as as we wrap up this + + align:start position:0% +again um espcially as as we wrap up this + + + align:start position:0% +again um espcially as as we wrap up this +course that you know this these Notions + + align:start position:0% +course that you know this these Notions + + + align:start position:0% +course that you know this these Notions +of Crees being lesser and to be + + align:start position:0% +of Crees being lesser and to be + + + align:start position:0% +of Crees being lesser and to be +excluded actually they've been fought + + align:start position:0% +excluded actually they've been fought + + + align:start position:0% +excluded actually they've been fought +against even in the 19th century so this + + align:start position:0% +against even in the 19th century so this + + + align:start position:0% +against even in the 19th century so this +is the Salin our first president and now + + align:start position:0% +is the Salin our first president and now + + + align:start position:0% +is the Salin our first president and now +this is the that famous quote in French + + align:start position:0% +this is the that famous quote in French + + + align:start position:0% +this is the that famous quote in French +because it's written by a French + + align:start position:0% +because it's written by a French + + + align:start position:0% +because it's written by a French +Observer and but the key Point here here + + align:start position:0% +Observer and but the key Point here here + + + align:start position:0% +Observer and but the key Point here here +is the fact that the saline would get + + align:start position:0% +is the fact that the saline would get + + + align:start position:0% +is the fact that the saline would get +very upset when someone was was back + + align:start position:0% +very upset when someone was was back + + + align:start position:0% +very upset when someone was was back +then well back they were they weren't + + align:start position:0% +then well back they were they weren't + + + align:start position:0% +then well back they were they weren't +haian yet because he was still under the + + align:start position:0% +haian yet because he was still under the + + + align:start position:0% +haian yet because he was still under the +The Colony but he would tell uh anyone + + align:start position:0% +The Colony but he would tell uh anyone + + + align:start position:0% +The Colony but he would tell uh anyone +who spoke French to him that you know + + align:start position:0% +who spoke French to him that you know + + + align:start position:0% +who spoke French to him that you know +why do you speak French you have your + + align:start position:0% +why do you speak French you have your + + + align:start position:0% +why do you speak French you have your +own language you know so this is cre + + align:start position:0% +own language you know so this is cre + + + align:start position:0% +own language you know so this is cre +actually you have your language and as + + align:start position:0% +actually you have your language and as + + + align:start position:0% +actually you have your language and as +he was um looking at them with disdain + + align:start position:0% +he was um looking at them with disdain + + + align:start position:0% +he was um looking at them with disdain +why look for + + align:start position:0% +why look for + + + align:start position:0% +why look for +another language why look for someone + + align:start position:0% +another language why look for someone + + + align:start position:0% +another language why look for someone +else's language so so the point is that + + align:start position:0% +else's language so so the point is that + + + align:start position:0% +else's language so so the point is that +thein even as he was technically a FR + + align:start position:0% +thein even as he was technically a FR + + + align:start position:0% +thein even as he was technically a FR +citizen as he was fighting for + + align:start position:0% +citizen as he was fighting for + + + align:start position:0% +citizen as he was fighting for +Independence he understood the power of + + align:start position:0% +Independence he understood the power of + + + align:start position:0% +Independence he understood the power of +the cre language okay and then now that + + align:start position:0% +the cre language okay and then now that + + + align:start position:0% +the cre language okay and then now that +same decid now this is um to remind you + + align:start position:0% +same decid now this is um to remind you + + + align:start position:0% +same decid now this is um to remind you +this length between you know politics + + align:start position:0% +this length between you know politics + + + align:start position:0% +this length between you know politics +and identity uh you know as he was so + + align:start position:0% +and identity uh you know as he was so + + + align:start position:0% +and identity uh you know as he was so +this is one of the first + + align:start position:0% +this is one of the first + + + align:start position:0% +this is one of the first +1805 uh um law in Haiti creating Haiti + + align:start position:0% +1805 uh um law in Haiti creating Haiti + + + align:start position:0% +1805 uh um law in Haiti creating Haiti +right so this is article one the people + + align:start position:0% +right so this is article one the people + + + align:start position:0% +right so this is article one the people +inhabiting the island from domain agree + + align:start position:0% +inhabiting the island from domain agree + + + align:start position:0% +inhabiting the island from domain agree +to form themselves into a free state + + align:start position:0% +to form themselves into a free state + + + align:start position:0% +to form themselves into a free state +Sovereign and independent of any other + + align:start position:0% +Sovereign and independent of any other + + + align:start position:0% +Sovereign and independent of any other +power right so this was the the most + + align:start position:0% +power right so this was the the most + + + align:start position:0% +power right so this was the the most +disturbing part about Haiti um slavery + + align:start position:0% +disturbing part about Haiti um slavery + + + align:start position:0% +disturbing part about Haiti um slavery +is abolished this was 1805 at the time + + align:start position:0% +is abolished this was 1805 at the time + + + align:start position:0% +is abolished this was 1805 at the time +when both Europe and the Americas both + + align:start position:0% +when both Europe and the Americas both + + + align:start position:0% +when both Europe and the Americas both +North and South America including + + align:start position:0% +North and South America including + + + align:start position:0% +North and South America including +countries like Colombia Venezuela + + align:start position:0% +countries like Colombia Venezuela + + + align:start position:0% +countries like Colombia Venezuela +Bolivia who actually been benefited from + + align:start position:0% +Bolivia who actually been benefited from + + + align:start position:0% +Bolivia who actually been benefited from +Haiti in terms of their own independence + + align:start position:0% +Haiti in terms of their own independence + + + align:start position:0% +Haiti in terms of their own independence +they still had slaves um so slavery is + + align:start position:0% +they still had slaves um so slavery is + + + align:start position:0% +they still had slaves um so slavery is +forever abolished um but the part that + + align:start position:0% +forever abolished um but the part that + + + align:start position:0% +forever abolished um but the part that +remember is also important is that + + align:start position:0% +remember is also important is that + + + align:start position:0% +remember is also important is that +excluding whites from owning any piece + + align:start position:0% +excluding whites from owning any piece + + + align:start position:0% +excluding whites from owning any piece +of Haiti which has now been changed um + + align:start position:0% +of Haiti which has now been changed um + + + align:start position:0% +of Haiti which has now been changed um +but that part that I want to stress is + + align:start position:0% +but that part that I want to stress is + + + align:start position:0% +but that part that I want to stress is +the fact that they understood also the + + align:start position:0% +the fact that they understood also the + + + align:start position:0% +the fact that they understood also the +power of identity now this is 1805 and + + align:start position:0% +power of identity now this is 1805 and + + + align:start position:0% +power of identity now this is 1805 and +he says that you know all uh exception + + align:start position:0% +he says that you know all uh exception + + + align:start position:0% +he says that you know all uh exception +means difference of color um + + align:start position:0% +means difference of color um + + + align:start position:0% +means difference of color um +will seize the Haitians shall henceforth + + align:start position:0% +will seize the Haitians shall henceforth + + + align:start position:0% +will seize the Haitians shall henceforth +be known only by dep of blacks okay + + align:start position:0% +be known only by dep of blacks okay + + + align:start position:0% +be known only by dep of blacks okay +that's 1805 okay was this written in + + align:start position:0% +that's 1805 okay was this written in + + + align:start position:0% +that's 1805 okay was this written in +English well well remember so this was + + align:start position:0% +English well well remember so this was + + + align:start position:0% +English well well remember so this was +at the time when this was both in + + align:start position:0% +at the time when this was both in + + + align:start position:0% +at the time when this was both in +English and French because thisin + + align:start position:0% +English and French because thisin + + + align:start position:0% +English and French because thisin +understood that he had to let the world + + align:start position:0% +understood that he had to let the world + + + align:start position:0% +understood that he had to let the world +know that this is my position in fact + + align:start position:0% +know that this is my position in fact + + + align:start position:0% +know that this is my position in fact +someone so this book + + align:start position:0% +someone so this book + + + align:start position:0% +someone so this book +here addresses this question so why why + + align:start position:0% +here addresses this question so why why + + + align:start position:0% +here addresses this question so why why +were why was the Salen since he was so + + align:start position:0% +were why was the Salen since he was so + + + align:start position:0% +were why was the Salen since he was so +procore why was he writing in French and + + align:start position:0% +procore why was he writing in French and + + + align:start position:0% +procore why was he writing in French and +English right and the point is that when + + align:start position:0% +English right and the point is that when + + + align:start position:0% +English right and the point is that when +he was speaking like here he was being + + align:start position:0% +he was speaking like here he was being + + + align:start position:0% +he was speaking like here he was being +cre but he when he had people right for + + align:start position:0% +cre but he when he had people right for + + + align:start position:0% +cre but he when he had people right for +him because he most most of the time he + + align:start position:0% +him because he most most of the time he + + + align:start position:0% +him because he most most of the time he +he had people right for him he wanted + + align:start position:0% +he had people right for him he wanted + + + align:start position:0% +he had people right for him he wanted +the world to understand what was his + + align:start position:0% +the world to understand what was his + + + align:start position:0% +the world to understand what was his +position about this issue right so he + + align:start position:0% +position about this issue right so he + + + align:start position:0% +position about this issue right so he +had to write in French and English + + align:start position:0% +had to write in French and English + + + align:start position:0% +had to write in French and English +because he was speaking to not to + + align:start position:0% +because he was speaking to not to + + + align:start position:0% +because he was speaking to not to +Haitians and he was speaking to they was + + align:start position:0% +Haitians and he was speaking to they was + + + align:start position:0% +Haitians and he was speaking to they was +say this is this is opposition so beware + + align:start position:0% +say this is this is opposition so beware + + + align:start position:0% +say this is this is opposition so beware +um but then of course you know + + align:start position:0% +um but then of course you know + + + align:start position:0% +um but then of course you know +um is what this this is a book from a + + align:start position:0% +um is what this this is a book from a + + + align:start position:0% +um is what this this is a book from a +book by Paul + + align:start position:0% +book by Paul + + + align:start position:0% +book by Paul +former so this part + + align:start position:0% +former so this part + + + align:start position:0% +former so this part +is moving from 1805 to the present and + + align:start position:0% +is moving from 1805 to the present and + + + align:start position:0% +is moving from 1805 to the present and +to understand why up to today they still + + align:start position:0% +to understand why up to today they still + + + align:start position:0% +to understand why up to today they still +the struggle around language and + + align:start position:0% +the struggle around language and + + + align:start position:0% +the struggle around language and +identity in the Caribbean you know + + align:start position:0% +identity in the Caribbean you know + + + align:start position:0% +identity in the Caribbean you know +especially Haiti is is you have to that + + align:start position:0% +especially Haiti is is you have to that + + + align:start position:0% +especially Haiti is is you have to that +from the very beginning uh after + + align:start position:0% +from the very beginning uh after + + + align:start position:0% +from the very beginning uh after +Independence there were all this + + align:start position:0% +Independence there were all this + + + align:start position:0% +Independence there were all this +pressure you know for hat to remain and + + align:start position:0% +pressure you know for hat to remain and + + + align:start position:0% +pressure you know for hat to remain and +the French dominion and under then + + align:start position:0% +the French dominion and under then + + + align:start position:0% +the French dominion and under then +American Dominion as you know you know + + align:start position:0% +American Dominion as you know you know + + + align:start position:0% +American Dominion as you know you know +America the US occupied Haiti for 15 + + align:start position:0% +America the US occupied Haiti for 15 + + + align:start position:0% +America the US occupied Haiti for 15 +years in the early part of the 20th + + align:start position:0% +years in the early part of the 20th + + + align:start position:0% +years in the early part of the 20th +century but even in 1825 the French + + align:start position:0% +century but even in 1825 the French + + + align:start position:0% +century but even in 1825 the French +managed to + + align:start position:0% +managed to + + + align:start position:0% +managed to +extract this + + align:start position:0% +extract this + + + align:start position:0% +extract this +Indemnity from Haiti for you know this + + align:start position:0% +Indemnity from Haiti for you know this + + + align:start position:0% +Indemnity from Haiti for you know this +is this was huge back then I think this + + align:start position:0% +is this was huge back then I think this + + + align:start position:0% +is this was huge back then I think this +is not worth you know billions of + + align:start position:0% +is not worth you know billions of + + + align:start position:0% +is not worth you know billions of +dollars can anyone can anyone read this + + align:start position:0% +dollars can anyone can anyone read this + + + align:start position:0% +dollars can anyone can anyone read this +uh from + + align:start position:0% +uh from + + + align:start position:0% +uh from +here who wants to read + + align:start position:0% +here who wants to read + + + align:start position:0% +here who wants to read +this okay K president V for 150 million + + align:start position:0% +this okay K president V for 150 million + + + align:start position:0% +this okay K president V for 150 million +Franks and the having of Customs charges + + align:start position:0% +Franks and the having of Customs charges + + + align:start position:0% +Franks and the having of Customs charges +for the French trade all as Indemnity + + align:start position:0% +for the French trade all as Indemnity + + + align:start position:0% +for the French trade all as Indemnity +for the losses of the plantation owners + + align:start position:0% +for the losses of the plantation owners + + + align:start position:0% +for the losses of the plantation owners +these conditions accepted in 1825 led to + + align:start position:0% +these conditions accepted in 1825 led to + + + align:start position:0% +these conditions accepted in 1825 led to +Decades of French domination of Haitian + + align:start position:0% +Decades of French domination of Haitian + + + align:start position:0% +Decades of French domination of Haitian +finance and had a catastrophic effect on + + align:start position:0% +finance and had a catastrophic effect on + + + align:start position:0% +finance and had a catastrophic effect on +the new nation's delicate economy + + align:start position:0% +the new nation's delicate economy + + + align:start position:0% +the new nation's delicate economy +despite its nominal Independence Haiti + + align:start position:0% +despite its nominal Independence Haiti + + + align:start position:0% +despite its nominal Independence Haiti +could not escape the shackles of foreign + + align:start position:0% +could not escape the shackles of foreign + + + align:start position:0% +could not escape the shackles of foreign +domination the very fact of a debt to + + align:start position:0% +domination the very fact of a debt to + + + align:start position:0% +domination the very fact of a debt to +France strikes the modern Observer as + + align:start position:0% +France strikes the modern Observer as + + + align:start position:0% +France strikes the modern Observer as +odd why might a country of former slaves + + align:start position:0% +odd why might a country of former slaves + + + align:start position:0% +odd why might a country of former slaves +feel compelled to enumerate the + + align:start position:0% +feel compelled to enumerate the + + + align:start position:0% +feel compelled to enumerate the +plantocracy for losses incurred in a war + + align:start position:0% +plantocracy for losses incurred in a war + + + align:start position:0% +plantocracy for losses incurred in a war +of Liberation yeah so so basically so + + align:start position:0% +of Liberation yeah so so basically so + + + align:start position:0% +of Liberation yeah so so basically so +the answer says that you know the elite + + align:start position:0% +the answer says that you know the elite + + + align:start position:0% +the answer says that you know the elite +had to make this compromise the elite + + align:start position:0% +had to make this compromise the elite + + + align:start position:0% +had to make this compromise the elite +wanted to be recognized by Europe and by + + align:start position:0% +wanted to be recognized by Europe and by + + + align:start position:0% +wanted to be recognized by Europe and by +and by America okay so and and so this + + align:start position:0% +and by America okay so and and so this + + + align:start position:0% +and by America okay so and and so this +struggle so that question here points to + + align:start position:0% +struggle so that question here points to + + + align:start position:0% +struggle so that question here points to +this basic ination history that from the + + align:start position:0% +this basic ination history that from the + + + align:start position:0% +this basic ination history that from the +very beginning uh the new Elite that + + align:start position:0% +very beginning uh the new Elite that + + + align:start position:0% +very beginning uh the new Elite that +became the the leader of the leaders of + + align:start position:0% +became the the leader of the leaders of + + + align:start position:0% +became the the leader of the leaders of +the country they in many ways replicated + + align:start position:0% +the country they in many ways replicated + + + align:start position:0% +the country they in many ways replicated +what the french had done you see um so + + align:start position:0% +what the french had done you see um so + + + align:start position:0% +what the french had done you see um so +that's why me so this is now after the + + align:start position:0% +that's why me so this is now after the + + + align:start position:0% +that's why me so this is now after the +earthquake this is from the Boston Globe + + align:start position:0% +earthquake this is from the Boston Globe + + + align:start position:0% +earthquake this is from the Boston Globe +right um and this is a straight + + align:start position:0% +right um and this is a straight + + + align:start position:0% +right um and this is a straight +continuation of what Paul Farmer + + align:start position:0% +continuation of what Paul Farmer + + + align:start position:0% +continuation of what Paul Farmer +discussed in that previous quote so + + align:start position:0% +discussed in that previous quote so + + + align:start position:0% +discussed in that previous quote so +wants to read this this part + + align:start position:0% + + + + align:start position:0% + +here + + align:start position:0% +here + + + align:start position:0% +here +good the question now is whether the + + align:start position:0% +good the question now is whether the + + + align:start position:0% +good the question now is whether the +wealthy Elite that controls the B the + + align:start position:0% +wealthy Elite that controls the B the + + + align:start position:0% +wealthy Elite that controls the B the +economy will help rebuild Haiti and + + align:start position:0% +economy will help rebuild Haiti and + + + align:start position:0% +economy will help rebuild Haiti and +create a thriving middle class 80% of + + align:start position:0% +create a thriving middle class 80% of + + + align:start position:0% +create a thriving middle class 80% of +patients live in poverty while a handful + + align:start position:0% +patients live in poverty while a handful + + + align:start position:0% +patients live in poverty while a handful +of often light-skinned descendants of + + align:start position:0% +of often light-skinned descendants of + + + align:start position:0% +of often light-skinned descendants of +the French who ruled the country's + + align:start position:0% +the French who ruled the country's + + + align:start position:0% +the French who ruled the country's +coffee and sugar slave plantations until + + align:start position:0% +coffee and sugar slave plantations until + + + align:start position:0% +coffee and sugar slave plantations until +Haiti declared independence in 1804 and + + align:start position:0% +Haiti declared independence in 1804 and + + + align:start position:0% +Haiti declared independence in 1804 and +other groups control most of the right + + align:start position:0% +other groups control most of the right + + + align:start position:0% +other groups control most of the right +so so basically you see the cleavage is + + align:start position:0% +so so basically you see the cleavage is + + + align:start position:0% +so so basically you see the cleavage is +still there right and this is so this + + align:start position:0% +still there right and this is so this + + + align:start position:0% +still there right and this is so this +cleavage and I think here know we can + + align:start position:0% +cleavage and I think here know we can + + + align:start position:0% +cleavage and I think here know we can +refer back to Karen and Rachel's + + align:start position:0% +refer back to Karen and Rachel's + + + align:start position:0% +refer back to Karen and Rachel's +presentation this cleavage between the + + align:start position:0% +presentation this cleavage between the + + + align:start position:0% +presentation this cleavage between the +elite and the masses also has this um + + align:start position:0% +elite and the masses also has this um + + + align:start position:0% +elite and the masses also has this um +this reflex this linguistic reflex where + + align:start position:0% +this reflex this linguistic reflex where + + + align:start position:0% +this reflex this linguistic reflex where +French is a language of power versus um + + align:start position:0% +French is a language of power versus um + + + align:start position:0% +French is a language of power versus um +Creole being the language that's still + + align:start position:0% +Creole being the language that's still + + + align:start position:0% +Creole being the language that's still +struggling uh to become a tool for for + + align:start position:0% +struggling uh to become a tool for for + + + align:start position:0% +struggling uh to become a tool for for +Liberation right so so here I think we + + align:start position:0% +Liberation right so so here I think we + + + align:start position:0% +Liberation right so so here I think we +have this um tight connection this tight + + align:start position:0% +have this um tight connection this tight + + + align:start position:0% +have this um tight connection this tight +Nexus between language power and an + + align:start position:0% +Nexus between language power and an + + + align:start position:0% +Nexus between language power and an +identity \ No newline at end of file diff --git a/MuRVOQY8KoY.txt b/MuRVOQY8KoY.txt new file mode 100644 index 0000000000000000000000000000000000000000..132cc48048ca118038a48deb31283258e73b7bb9 --- /dev/null +++ b/MuRVOQY8KoY.txt @@ -0,0 +1,19555 @@ +align:start position:0% + +here's the agenda for today as usual a + + align:start position:0% +here's the agenda for today as usual a + + + align:start position:0% +here's the agenda for today as usual a +bunch of announcements in + + align:start position:0% +bunch of announcements in + + + align:start position:0% +bunch of announcements in +red assignment 4 was graded there will + + align:start position:0% +red assignment 4 was graded there will + + + align:start position:0% +red assignment 4 was graded there will +be + + align:start position:0% +be + + + align:start position:0% +be +comments showing up online on stellar + + align:start position:0% +comments showing up online on stellar + + + align:start position:0% +comments showing up online on stellar +soon on any of you didn't get a near + + align:start position:0% +soon on any of you didn't get a near + + + align:start position:0% +soon on any of you didn't get a near +perfect score + + align:start position:0% +perfect score + + + align:start position:0% +perfect score +on it and i'll also be going over a + + align:start position:0% +on it and i'll also be going over a + + + align:start position:0% +on it and i'll also be going over a +little bit of it in + + align:start position:0% +little bit of it in + + + align:start position:0% +little bit of it in +in a moment + + align:start position:0% +in a moment + + + align:start position:0% +in a moment +and then once we do that we're going to + + align:start position:0% +and then once we do that we're going to + + + align:start position:0% +and then once we do that we're going to +talk about navigation how we know where + + align:start position:0% +talk about navigation how we know where + + + align:start position:0% +talk about navigation how we know where +we are and how to get from here to + + align:start position:0% +we are and how to get from here to + + + align:start position:0% +we are and how to get from here to +someplace else which is much more + + align:start position:0% +someplace else which is much more + + + align:start position:0% +someplace else which is much more +awesome than it sounds at first as you + + align:start position:0% +awesome than it sounds at first as you + + + align:start position:0% +awesome than it sounds at first as you +will see + + align:start position:0% +will see + + + align:start position:0% +will see +okay so quick uh review + + align:start position:0% +okay so quick uh review + + + align:start position:0% +okay so quick uh review +um okay so what was the key point why + + align:start position:0% +um okay so what was the key point why + + + align:start position:0% +um okay so what was the key point why +did i assign the hackspeed 2001 article + + align:start position:0% +did i assign the hackspeed 2001 article + + + align:start position:0% +did i assign the hackspeed 2001 article +for you guys to read it it presents this + + align:start position:0% +for you guys to read it it presents this + + + align:start position:0% +for you guys to read it it presents this +important challenge to the functional + + align:start position:0% +important challenge to the functional + + + align:start position:0% +important challenge to the functional +specificity of the face area and the + + align:start position:0% +specificity of the face area and the + + + align:start position:0% +specificity of the face area and the +place area what was that challenge + + align:start position:0% +place area what was that challenge + + + align:start position:0% +place area what was that challenge +what was hacksby's key point + + align:start position:0% +what was hacksby's key point + + + align:start position:0% +what was hacksby's key point +yes isabelle whether the um + + align:start position:0% +yes isabelle whether the um + + + align:start position:0% +yes isabelle whether the um +va is just + + align:start position:0% +va is just + + + align:start position:0% +va is just +attracts like it's just uh + + align:start position:0% +attracts like it's just uh + + + align:start position:0% +attracts like it's just uh +has a preference for rick linear + + align:start position:0% +has a preference for rick linear + + + align:start position:0% +has a preference for rick linear +that's what central standard for it's + + align:start position:0% +that's what central standard for it's + + + align:start position:0% +that's what central standard for it's +not truly detecting whether something + + align:start position:0% + + + + align:start position:0% + +yeah he wasn't worrying about + + align:start position:0% +yeah he wasn't worrying about + + + align:start position:0% +yeah he wasn't worrying about +rectilinearity so much back then but his + + align:start position:0% +rectilinearity so much back then but his + + + align:start position:0% +rectilinearity so much back then but his +point was that if you that we shouldn't + + align:start position:0% +point was that if you that we shouldn't + + + align:start position:0% +point was that if you that we shouldn't +care just about the overall magnitude of + + align:start position:0% +care just about the overall magnitude of + + + align:start position:0% +care just about the overall magnitude of +response of a region like okay it's nice + + align:start position:0% +response of a region like okay it's nice + + + align:start position:0% +response of a region like okay it's nice +if the face area responds like this to + + align:start position:0% +if the face area responds like this to + + + align:start position:0% +if the face area responds like this to +face isn't like that to objects + + align:start position:0% +face isn't like that to objects + + + align:start position:0% +face isn't like that to objects +but even if it responds low and the same + + align:start position:0% +but even if it responds low and the same + + + align:start position:0% +but even if it responds low and the same +to cars and chairs + + align:start position:0% +to cars and chairs + + + align:start position:0% +to cars and chairs +it might still have information to + + align:start position:0% +it might still have information to + + + align:start position:0% +it might still have information to +enable you to distinguish cars from + + align:start position:0% +enable you to distinguish cars from + + + align:start position:0% +enable you to distinguish cars from +chairs if the pattern of response across + + align:start position:0% +chairs if the pattern of response across + + + align:start position:0% +chairs if the pattern of response across +voxels in that region was stably + + align:start position:0% +voxels in that region was stably + + + align:start position:0% +voxels in that region was stably +different for cars and chairs + + align:start position:0% +different for cars and chairs + + + align:start position:0% +different for cars and chairs +okay that's really key we'll go over it + + align:start position:0% +okay that's really key we'll go over it + + + align:start position:0% +okay that's really key we'll go over it +a few more points but that's that's + + align:start position:0% +a few more points but that's that's + + + align:start position:0% +a few more points but that's that's +essential right a lot of the details + + align:start position:0% +essential right a lot of the details + + + align:start position:0% +essential right a lot of the details +that i'm going to teach you that that go + + align:start position:0% +that i'm going to teach you that that go + + + align:start position:0% +that i'm going to teach you that that go +by in class don't matter but i really + + align:start position:0% +by in class don't matter but i really + + + align:start position:0% +by in class don't matter but i really +want you guys to understand in vpa and + + align:start position:0% +want you guys to understand in vpa and + + + align:start position:0% +want you guys to understand in vpa and +that's the nub of it okay so the idea is + + align:start position:0% +that's the nub of it okay so the idea is + + + align:start position:0% +that's the nub of it okay so the idea is +that selective his + + align:start position:0% +that selective his + + + align:start position:0% +that selective his +his kind of um + + align:start position:0% +his kind of um + + + align:start position:0% +his kind of um +claim is that selective regions like the + + align:start position:0% +claim is that selective regions like the + + + align:start position:0% +claim is that selective regions like the +face area contain information about + + align:start position:0% +face area contain information about + + + align:start position:0% +face area contain information about +non-preferred stimuli that is like + + align:start position:0% +non-preferred stimuli that is like + + + align:start position:0% +non-preferred stimuli that is like +non-faces for the face area or + + align:start position:0% +non-faces for the face area or + + + align:start position:0% +non-faces for the face area or +non-places for the place area + + align:start position:0% +non-places for the place area + + + align:start position:0% +non-places for the place area +and because they contain information + + align:start position:0% +and because they contain information + + + align:start position:0% +and because they contain information +those regions don't care only about + + align:start position:0% +those regions don't care only about + + + align:start position:0% +those regions don't care only about +their preferred category so + + align:start position:0% +their preferred category so + + + align:start position:0% +their preferred category so +why does can washer get off saying the + + align:start position:0% +why does can washer get off saying the + + + align:start position:0% +why does can washer get off saying the +ffa is only about faces and the ppa is + + align:start position:0% +ffa is only about faces and the ppa is + + + align:start position:0% +ffa is only about faces and the ppa is +only about places if we can see + + align:start position:0% +only about places if we can see + + + align:start position:0% +only about places if we can see +information about other things in those + + align:start position:0% +information about other things in those + + + align:start position:0% +information about other things in those +regions okay that's a really important + + align:start position:0% +regions okay that's a really important + + + align:start position:0% +regions okay that's a really important +critique that's why we're spending time + + align:start position:0% +critique that's why we're spending time + + + align:start position:0% +critique that's why we're spending time +on it okay okay + + align:start position:0% +on it okay okay + + + align:start position:0% +on it okay okay +next what kind of empirical data + + align:start position:0% +next what kind of empirical data + + + align:start position:0% +next what kind of empirical data +might + + align:start position:0% +might + + + align:start position:0% +might +be an answer + + align:start position:0% +be an answer + + + align:start position:0% +be an answer +to haxby's charge + + align:start position:0% +to haxby's charge + + + align:start position:0% +to haxby's charge +i've presented at least three different + + align:start position:0% +i've presented at least three different + + + align:start position:0% +i've presented at least three different +kinds of data that can address this and + + align:start position:0% +kinds of data that can address this and + + + align:start position:0% +kinds of data that can address this and +say hey wait a minute you know you have + + align:start position:0% +say hey wait a minute you know you have + + + align:start position:0% +say hey wait a minute you know you have +a point but + + align:start position:0% +a point but + + + align:start position:0% +a point but +what kind of data could speak to that + + align:start position:0% +what kind of data could speak to that + + + align:start position:0% +what kind of data could speak to that +and respond to to hacksby + + align:start position:0% +and respond to to hacksby + + + align:start position:0% +and respond to to hacksby +we didn't actually talk about this + + align:start position:0% +we didn't actually talk about this + + + align:start position:0% +we didn't actually talk about this +explicitly in class but think about it + + align:start position:0% +explicitly in class but think about it + + + align:start position:0% +explicitly in class but think about it +here's the here's the claim he makes + + align:start position:0% +here's the here's the claim he makes + + + align:start position:0% +here's the here's the claim he makes +what might we say right so that's that's + + align:start position:0% +what might we say right so that's that's + + + align:start position:0% +what might we say right so that's that's +empirically true like you look in the + + align:start position:0% +empirically true like you look in the + + + align:start position:0% +empirically true like you look in the +ffa even in my own data i can + + align:start position:0% +ffa even in my own data i can + + + align:start position:0% +ffa even in my own data i can +distinguish + + align:start position:0% +distinguish + + + align:start position:0% +distinguish +uh chairs from shoes a little teeny bit + + align:start position:0% +uh chairs from shoes a little teeny bit + + + align:start position:0% +uh chairs from shoes a little teeny bit +in the ffa okay so that empirical claim + + align:start position:0% +in the ffa okay so that empirical claim + + + align:start position:0% +in the ffa okay so that empirical claim +is true + + align:start position:0% +is true + + + align:start position:0% +is true +why might it nonetheless + + align:start position:0% +why might it nonetheless + + + align:start position:0% +why might it nonetheless +be the case + + align:start position:0% +be the case + + + align:start position:0% +be the case +that the face area is really only about + + align:start position:0% +that the face area is really only about + + + align:start position:0% +that the face area is really only about +face recognition what other data have + + align:start position:0% +face recognition what other data have + + + align:start position:0% +face recognition what other data have +you heard + + align:start position:0% +you heard + + + align:start position:0% +you heard +in here that might + + align:start position:0% +in here that might + + + align:start position:0% +in here that might +make you think that yes ben + + align:start position:0% + + + + align:start position:0% + +yes + + align:start position:0% +yes + + + align:start position:0% +yes +sorry the + + align:start position:0% +sorry the + + + align:start position:0% +sorry the +presence of low-level stimuli that are + + align:start position:0% +presence of low-level stimuli that are + + + align:start position:0% +presence of low-level stimuli that are +generally in bases but can also + + align:start position:0% +generally in bases but can also + + + align:start position:0% +generally in bases but can also +um sparsely adopt chairs and cars + + align:start position:0% +um sparsely adopt chairs and cars + + + align:start position:0% +um sparsely adopt chairs and cars +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +absolutely so yes so put another way + + align:start position:0% +absolutely so yes so put another way + + + align:start position:0% +absolutely so yes so put another way +even if you had a perfect + + align:start position:0% +even if you had a perfect + + + align:start position:0% +even if you had a perfect +coder for faces you know like take your + + align:start position:0% +coder for faces you know like take your + + + align:start position:0% +coder for faces you know like take your +best deep net for face recognition vgg + + align:start position:0% +best deep net for face recognition vgg + + + align:start position:0% +best deep net for face recognition vgg +face + + align:start position:0% +face + + + align:start position:0% +face +it can distinguish chairs and shoes too + + align:start position:0% +it can distinguish chairs and shoes too + + + align:start position:0% +it can distinguish chairs and shoes too +right the features that you use to + + align:start position:0% +right the features that you use to + + + align:start position:0% +right the features that you use to +represent faces will slightly + + align:start position:0% +represent faces will slightly + + + align:start position:0% +represent faces will slightly +discriminate between other non-face + + align:start position:0% +discriminate between other non-face + + + align:start position:0% +discriminate between other non-face +objects so the fact that we can see that + + align:start position:0% +objects so the fact that we can see that + + + align:start position:0% +objects so the fact that we can see that +information in itself isn't strong + + align:start position:0% +information in itself isn't strong + + + align:start position:0% +information in itself isn't strong +evidence that that region isn't doing + + align:start position:0% +evidence that that region isn't doing + + + align:start position:0% +evidence that that region isn't doing +selectively isn't selective for face + + align:start position:0% +selectively isn't selective for face + + + align:start position:0% +selectively isn't selective for face +perception absolutely what else + + align:start position:0% + + + + align:start position:0% + +yeah okay with the like transcranial + + align:start position:0% +yeah okay with the like transcranial + + + align:start position:0% +yeah okay with the like transcranial +magnetic stimulation that when you + + align:start position:0% +magnetic stimulation that when you + + + align:start position:0% +magnetic stimulation that when you +stimulate like the ffa you look at a + + align:start position:0% +stimulate like the ffa you look at a + + + align:start position:0% +stimulate like the ffa you look at a +face that affects it but when you are + + align:start position:0% +face that affects it but when you are + + + align:start position:0% +face that affects it but when you are +looking at other objects + + align:start position:0% +looking at other objects + + + align:start position:0% +looking at other objects +exactly and so what does that tell you + + align:start position:0% +exactly and so what does that tell you + + + align:start position:0% +exactly and so what does that tell you +about okay so there's pattern + + align:start position:0% +about okay so there's pattern + + + align:start position:0% +about okay so there's pattern +information in there + + align:start position:0% +information in there + + + align:start position:0% +information in there +about other things beyond faces + + align:start position:0% +about other things beyond faces + + + align:start position:0% +about other things beyond faces +but + + align:start position:0% +but + + + align:start position:0% +but +apparently it's not used right + + align:start position:0% +apparently it's not used right + + + align:start position:0% +apparently it's not used right +now with every bit of evidence you can + + align:start position:0% +now with every bit of evidence you can + + + align:start position:0% +now with every bit of evidence you can +always argue back people say well tms + + align:start position:0% +always argue back people say well tms + + + align:start position:0% +always argue back people say well tms +those effects are tiny maybe there isn't + + align:start position:0% +those effects are tiny maybe there isn't + + + align:start position:0% +those effects are tiny maybe there isn't +we didn't have power detected blah blah + + align:start position:0% +we didn't have power detected blah blah + + + align:start position:0% +we didn't have power detected blah blah +blah blah but at least absolutely you're + + align:start position:0% +blah blah but at least absolutely you're + + + align:start position:0% +blah blah but at least absolutely you're +right tms argues against that what else + + align:start position:0% +right tms argues against that what else + + + align:start position:0% +right tms argues against that what else +or at least is a way to argue against it + + align:start position:0% +or at least is a way to argue against it + + + align:start position:0% +or at least is a way to argue against it +and the picture paper that i assigned + + align:start position:0% +and the picture paper that i assigned + + + align:start position:0% +and the picture paper that i assigned +and other papers that we've talked about + + align:start position:0% +and other papers that we've talked about + + + align:start position:0% +and other papers that we've talked about +in here provide some evidence that + + align:start position:0% +in here provide some evidence that + + + align:start position:0% +in here provide some evidence that +actually at least the occipital face + + align:start position:0% +actually at least the occipital face + + + align:start position:0% +actually at least the occipital face +area really is only causally involved in + + align:start position:0% +area really is only causally involved in + + + align:start position:0% +area really is only causally involved in +face perception even if there's + + align:start position:0% +face perception even if there's + + + align:start position:0% +face perception even if there's +information in there about other things + + align:start position:0% +information in there about other things + + + align:start position:0% +information in there about other things +okay + + align:start position:0% +okay + + + align:start position:0% +okay +what else what other methods can address + + align:start position:0% +what else what other methods can address + + + align:start position:0% +what else what other methods can address +this + + align:start position:0% +this + + + align:start position:0% +this +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +simulation + + align:start position:0% +simulation + + + align:start position:0% +simulation +even when you president + + align:start position:0% +even when you president + + + align:start position:0% +even when you president +takes uh + + align:start position:0% + + + + align:start position:0% + +exactly exactly so these are both causal + + align:start position:0% +exactly exactly so these are both causal + + + align:start position:0% +exactly exactly so these are both causal +tests right okay there's information in + + align:start position:0% +tests right okay there's information in + + + align:start position:0% +tests right okay there's information in +there but is it causally used in + + align:start position:0% +there but is it causally used in + + + align:start position:0% +there but is it causally used in +behavior right tms suggests not the + + align:start position:0% +behavior right tms suggests not the + + + align:start position:0% +behavior right tms suggests not the +little bit of + + align:start position:0% +little bit of + + + align:start position:0% +little bit of +a direct + + align:start position:0% +a direct + + + align:start position:0% +a direct +intracranial stimulation data that i + + align:start position:0% +intracranial stimulation data that i + + + align:start position:0% +intracranial stimulation data that i +showed you also suggests the causal + + align:start position:0% +showed you also suggests the causal + + + align:start position:0% +showed you also suggests the causal +effects when you stimulate that region + + align:start position:0% +effects when you stimulate that region + + + align:start position:0% +effects when you stimulate that region +are specific to face perception again + + align:start position:0% +are specific to face perception again + + + align:start position:0% +are specific to face perception again +suggesting that even if there's pattern + + align:start position:0% +suggesting that even if there's pattern + + + align:start position:0% +suggesting that even if there's pattern +information in there it's not doing + + align:start position:0% +information in there it's not doing + + + align:start position:0% +information in there it's not doing +anything important because we can mess + + align:start position:0% +anything important because we can mess + + + align:start position:0% +anything important because we can mess +it up and nothing happens to the + + align:start position:0% +it up and nothing happens to the + + + align:start position:0% +it up and nothing happens to the +perception of things that aren't faces + + align:start position:0% +perception of things that aren't faces + + + align:start position:0% +perception of things that aren't faces +absolutely what else + + align:start position:0% + + + + align:start position:0% + +we talked about it very briefly a few + + align:start position:0% +we talked about it very briefly a few + + + align:start position:0% +we talked about it very briefly a few +weeks ago + + align:start position:0% +weeks ago + + + align:start position:0% +weeks ago +yeah + + align:start position:0% + + + + align:start position:0% + +it just completely makes a person + + align:start position:0% +it just completely makes a person + + + align:start position:0% +it just completely makes a person +incapable of perceiving this that that + + align:start position:0% +incapable of perceiving this that that + + + align:start position:0% +incapable of perceiving this that that +is like + + align:start position:0% +is like + + + align:start position:0% +is like +yes but yes but the crucial way yes but + + align:start position:0% +yes but yes but the crucial way yes but + + + align:start position:0% +yes but yes but the crucial way yes but +the crucial way + + align:start position:0% +the crucial way + + + align:start position:0% +the crucial way +to address hacks be be would be what + + align:start position:0% +to address hacks be be would be what + + + align:start position:0% +to address hacks be be would be what +further aspect of that yes + + align:start position:0% +further aspect of that yes + + + align:start position:0% +further aspect of that yes +apparently and by the way we don't + + align:start position:0% +apparently and by the way we don't + + + align:start position:0% +apparently and by the way we don't +remove the area in humans + + align:start position:0% +remove the area in humans + + + align:start position:0% +remove the area in humans +but occasionally we find a human who had + + align:start position:0% +but occasionally we find a human who had + + + align:start position:0% +but occasionally we find a human who had +a lesion there due to a stroke and then + + align:start position:0% +a lesion there due to a stroke and then + + + align:start position:0% +a lesion there due to a stroke and then +we studied them so they're still able to + + align:start position:0% +we studied them so they're still able to + + + align:start position:0% +we studied them so they're still able to +do other categories exactly + + align:start position:0% +do other categories exactly + + + align:start position:0% +do other categories exactly +exactly so all three lines of evidence + + align:start position:0% +exactly so all three lines of evidence + + + align:start position:0% +exactly so all three lines of evidence +and + + align:start position:0% +and + + + align:start position:0% +and +suggest from studies of prosopagnosia + + align:start position:0% +suggest from studies of prosopagnosia + + + align:start position:0% +suggest from studies of prosopagnosia +electrical stimulation directly on the + + align:start position:0% +electrical stimulation directly on the + + + align:start position:0% +electrical stimulation directly on the +brain and tms all can provide evidence + + align:start position:0% +brain and tms all can provide evidence + + + align:start position:0% +brain and tms all can provide evidence +to various degrees again one can quibble + + align:start position:0% +to various degrees again one can quibble + + + align:start position:0% +to various degrees again one can quibble +about each of these particular studies + + align:start position:0% +about each of these particular studies + + + align:start position:0% +about each of these particular studies +but all of those suggest that even + + align:start position:0% +but all of those suggest that even + + + align:start position:0% +but all of those suggest that even +though there's information in the + + align:start position:0% +though there's information in the + + + align:start position:0% +though there's information in the +pattern haxby's right there's + + align:start position:0% +pattern haxby's right there's + + + align:start position:0% +pattern haxby's right there's +information in there about other things + + align:start position:0% +information in there about other things + + + align:start position:0% +information in there about other things +that aren't faces the only causal + + align:start position:0% +that aren't faces the only causal + + + align:start position:0% +that aren't faces the only causal +effects when you mess up with that + + align:start position:0% +effects when you mess up with that + + + align:start position:0% +effects when you mess up with that +region are on faces not on other things + + align:start position:0% +region are on faces not on other things + + + align:start position:0% +region are on faces not on other things +that suggests that pattern information + + align:start position:0% +that suggests that pattern information + + + align:start position:0% +that suggests that pattern information +is what they sometimes say in + + align:start position:0% +is what they sometimes say in + + + align:start position:0% +is what they sometimes say in +philosophical circles as epi phenomenal + + align:start position:0% +philosophical circles as epi phenomenal + + + align:start position:0% +philosophical circles as epi phenomenal +that is it's just not related to + + align:start position:0% +that is it's just not related to + + + align:start position:0% +that is it's just not related to +um to + + align:start position:0% +um to + + + align:start position:0% +um to +behavior and and + + align:start position:0% +behavior and and + + + align:start position:0% +behavior and and +perception makes sense okay + + align:start position:0% +perception makes sense okay + + + align:start position:0% +perception makes sense okay +moving along + + align:start position:0% +moving along + + + align:start position:0% +moving along +how can we then use haxby's method to + + align:start position:0% +how can we then use haxby's method to + + + align:start position:0% +how can we then use haxby's method to +not just engage in this little fight + + align:start position:0% +not just engage in this little fight + + + align:start position:0% +not just engage in this little fight +about the ffa and how specific it is + + align:start position:0% +about the ffa and how specific it is + + + align:start position:0% +about the ffa and how specific it is +um but to ask whether to harness this + + align:start position:0% +um but to ask whether to harness this + + + align:start position:0% +um but to ask whether to harness this +method and ask other interesting + + align:start position:0% +method and ask other interesting + + + align:start position:0% +method and ask other interesting +questions + + align:start position:0% +questions + + + align:start position:0% +questions +from functional mri data how can we use + + align:start position:0% +from functional mri data how can we use + + + align:start position:0% +from functional mri data how can we use +it to find out for example does the + + align:start position:0% +it to find out for example does the + + + align:start position:0% +it to find out for example does the +place area discriminate say beach scenes + + align:start position:0% +place area discriminate say beach scenes + + + align:start position:0% +place area discriminate say beach scenes +from city scenes we want to know what's + + align:start position:0% +from city scenes we want to know what's + + + align:start position:0% +from city scenes we want to know what's +represented in there how could we use + + align:start position:0% +represented in there how could we use + + + align:start position:0% +represented in there how could we use +this method to find out + + align:start position:0% + + + + align:start position:0% + +yes + + align:start position:0% + + + + align:start position:0% + +because i did and like trying to decode + + align:start position:0% +because i did and like trying to decode + + + align:start position:0% +because i did and like trying to decode +her and see if it could + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +exactly + + align:start position:0% +exactly + + + align:start position:0% +exactly +exactly so we talked about decoding + + align:start position:0% +exactly so we talked about decoding + + + align:start position:0% +exactly so we talked about decoding +methods last time as a way to use + + align:start position:0% +methods last time as a way to use + + + align:start position:0% +methods last time as a way to use +machine learning to look at the pattern + + align:start position:0% +machine learning to look at the pattern + + + align:start position:0% +machine learning to look at the pattern +of response in a region of the brain + + align:start position:0% +of response in a region of the brain + + + align:start position:0% +of response in a region of the brain +and train the decoder so it knows what + + align:start position:0% +and train the decoder so it knows what + + + align:start position:0% +and train the decoder so it knows what +bc what the response looks like + + align:start position:0% +bc what the response looks like + + + align:start position:0% +bc what the response looks like +during viewing of beach scenes train it + + align:start position:0% +during viewing of beach scenes train it + + + align:start position:0% +during viewing of beach scenes train it +so it knows what the response in that + + align:start position:0% +so it knows what the response in that + + + align:start position:0% +so it knows what the response in that +region looks like when you're looking at + + align:start position:0% +region looks like when you're looking at + + + align:start position:0% +region looks like when you're looking at +city schemes and then take a new pattern + + align:start position:0% +city schemes and then take a new pattern + + + align:start position:0% +city schemes and then take a new pattern +and say okay is this more like the beach + + align:start position:0% +and say okay is this more like the beach + + + align:start position:0% +and say okay is this more like the beach +pattern or is it more like the city + + align:start position:0% +pattern or is it more like the city + + + align:start position:0% +pattern or is it more like the city +pattern and that's how you could decode + + align:start position:0% +pattern and that's how you could decode + + + align:start position:0% +pattern and that's how you could decode +from that region yes that doesn't tell + + align:start position:0% +from that region yes that doesn't tell + + + align:start position:0% +from that region yes that doesn't tell +us right in the sense that it's + + align:start position:0% +us right in the sense that it's + + + align:start position:0% +us right in the sense that it's +it's not telling the i mean we know that + + align:start position:0% +it's not telling the i mean we know that + + + align:start position:0% +it's not telling the i mean we know that +the this residue of information + + align:start position:0% +the this residue of information + + + align:start position:0% +the this residue of information +nevertheless and a discriminator can be + + align:start position:0% +nevertheless and a discriminator can be + + + align:start position:0% +nevertheless and a discriminator can be +built on any region to figure out + + align:start position:0% +built on any region to figure out + + + align:start position:0% +built on any region to figure out +anything + + align:start position:0% +anything + + + align:start position:0% +anything +almost + + align:start position:0% +almost + + + align:start position:0% +almost +so + + align:start position:0% +so + + + align:start position:0% +so +we have a true nile list here + + align:start position:0% +we have a true nile list here + + + align:start position:0% +we have a true nile list here +um no it's a good question + + align:start position:0% +um no it's a good question + + + align:start position:0% +um no it's a good question +it's not the case + + align:start position:0% +it's not the case + + + align:start position:0% +it's not the case +that you can discriminate anything based + + align:start position:0% +that you can discriminate anything based + + + align:start position:0% +that you can discriminate anything based +on any region of the brain + + align:start position:0% +on any region of the brain + + + align:start position:0% +on any region of the brain +so there are some constraints there's + + align:start position:0% +so there are some constraints there's + + + align:start position:0% +so there are some constraints there's +some things you can find in some places + + align:start position:0% +some things you can find in some places + + + align:start position:0% +some things you can find in some places +and other things you can find + + align:start position:0% +and other things you can find + + + align:start position:0% +and other things you can find +in other places and they're not + + align:start position:0% +in other places and they're not + + + align:start position:0% +in other places and they're not +uniformly distributed over the brain + + align:start position:0% +uniformly distributed over the brain + + + align:start position:0% +uniformly distributed over the brain +however the fact we just the point i + + align:start position:0% +however the fact we just the point i + + + align:start position:0% +however the fact we just the point i +just made about yes there's + + align:start position:0% +just made about yes there's + + + align:start position:0% +just made about yes there's +discriminative information in the face + + align:start position:0% +discriminative information in the face + + + align:start position:0% +discriminative information in the face +area about non-faces but maybe it's not + + align:start position:0% +area about non-faces but maybe it's not + + + align:start position:0% +area about non-faces but maybe it's not +used + + align:start position:0% +used + + + align:start position:0% +used +should raise a huge caveat about this + + align:start position:0% +should raise a huge caveat about this + + + align:start position:0% +should raise a huge caveat about this +whole method how do we ever know we see + + align:start position:0% +whole method how do we ever know we see + + + align:start position:0% +whole method how do we ever know we see +some discriminative information how do + + align:start position:0% +some discriminative information how do + + + align:start position:0% +some discriminative information how do +we know whether it's actually used by + + align:start position:0% +we know whether it's actually used by + + + align:start position:0% +we know whether it's actually used by +the brain part of the brain's own code + + align:start position:0% +the brain part of the brain's own code + + + align:start position:0% +the brain part of the brain's own code +for information or just epiphenomenal + + align:start position:0% +for information or just epiphenomenal + + + align:start position:0% +for information or just epiphenomenal +garbage that's a byproduct of something + + align:start position:0% +garbage that's a byproduct of something + + + align:start position:0% +garbage that's a byproduct of something +else + + align:start position:0% +else + + + align:start position:0% +else +it's a really important question about + + align:start position:0% +it's a really important question about + + + align:start position:0% +it's a really important question about +all of pattern analysis + + align:start position:0% +all of pattern analysis + + + align:start position:0% +all of pattern analysis +okay we do it anyway because we're + + align:start position:0% +okay we do it anyway because we're + + + align:start position:0% +okay we do it anyway because we're +beggars we can't be choosers in terms of + + align:start position:0% +beggars we can't be choosers in terms of + + + align:start position:0% +beggars we can't be choosers in terms of +methods with human cognitive + + align:start position:0% +methods with human cognitive + + + align:start position:0% +methods with human cognitive +neuroscience and we want to know + + align:start position:0% +neuroscience and we want to know + + + align:start position:0% +neuroscience and we want to know +desperately what's represented in each + + align:start position:0% +desperately what's represented in each + + + align:start position:0% +desperately what's represented in each +region so we do this but whenever you + + align:start position:0% +region so we do this but whenever you + + + align:start position:0% +region so we do this but whenever you +see these lovely i can decode x from y + + align:start position:0% +see these lovely i can decode x from y + + + align:start position:0% +see these lovely i can decode x from y +things you should always be wondering + + align:start position:0% +things you should always be wondering + + + align:start position:0% +things you should always be wondering +who knows if that fact that you the + + align:start position:0% +who knows if that fact that you the + + + align:start position:0% +who knows if that fact that you the +scientist can decode it from that region + + align:start position:0% +scientist can decode it from that region + + + align:start position:0% +scientist can decode it from that region +means the brain itself is reading that + + align:start position:0% +means the brain itself is reading that + + + align:start position:0% +means the brain itself is reading that +information out of that region + + align:start position:0% +information out of that region + + + align:start position:0% +information out of that region +big important question + + align:start position:0% +big important question + + + align:start position:0% +big important question +okay + + align:start position:0% +okay + + + align:start position:0% +okay +all right put another way um so jimmy + + align:start position:0% +all right put another way um so jimmy + + + align:start position:0% +all right put another way um so jimmy +mentioned just decoding in general + + align:start position:0% +mentioned just decoding in general + + + align:start position:0% +mentioned just decoding in general +that's absolutely right but to directly + + align:start position:0% +that's absolutely right but to directly + + + align:start position:0% +that's absolutely right but to directly +harness the haxby version of this what + + align:start position:0% +harness the haxby version of this what + + + align:start position:0% +harness the haxby version of this what +would we do first we would functionally + + align:start position:0% +would we do first we would functionally + + + align:start position:0% +would we do first we would functionally +localize the ppa + + align:start position:0% +localize the ppa + + + align:start position:0% +localize the ppa +but by scanning them looking at scenes + + align:start position:0% +but by scanning them looking at scenes + + + align:start position:0% +but by scanning them looking at scenes +and objects find that region in each + + align:start position:0% +and objects find that region in each + + + align:start position:0% +and objects find that region in each +subject + + align:start position:0% +subject + + + align:start position:0% +subject +then we would collect the pattern of + + align:start position:0% +then we would collect the pattern of + + + align:start position:0% +then we would collect the pattern of +response across voxels in the ppa + + align:start position:0% +response across voxels in the ppa + + + align:start position:0% +response across voxels in the ppa +while subjects were looking at say beach + + align:start position:0% +while subjects were looking at say beach + + + align:start position:0% +while subjects were looking at say beach +scenes and so if this is the ppa this is + + align:start position:0% +scenes and so if this is the ppa this is + + + align:start position:0% +scenes and so if this is the ppa this is +the pattern of response across voxels in + + align:start position:0% +the pattern of response across voxels in + + + align:start position:0% +the pattern of response across voxels in +that region when they're looking at + + align:start position:0% +that region when they're looking at + + + align:start position:0% +that region when they're looking at +beach scenes fake data obviously just to + + align:start position:0% +beach scenes fake data obviously just to + + + align:start position:0% +beach scenes fake data obviously just to +give you the idea + + align:start position:0% +give you the idea + + + align:start position:0% +give you the idea +right so we would split the data in half + + align:start position:0% +right so we would split the data in half + + + align:start position:0% +right so we would split the data in half +even runs odd runs that would be like + + align:start position:0% +even runs odd runs that would be like + + + align:start position:0% +even runs odd runs that would be like +even runs then we get another pattern + + align:start position:0% +even runs then we get another pattern + + + align:start position:0% +even runs then we get another pattern +for odd runs and then we get another + + align:start position:0% +for odd runs and then we get another + + + align:start position:0% +for odd runs and then we get another +pattern for when they're looking at city + + align:start position:0% +pattern for when they're looking at city + + + align:start position:0% +pattern for when they're looking at city +scenes with even runs and another + + align:start position:0% +scenes with even runs and another + + + align:start position:0% +scenes with even runs and another +pattern when they're looking at city + + align:start position:0% +pattern when they're looking at city + + + align:start position:0% +pattern when they're looking at city +scenes and odd runs okay + + align:start position:0% +scenes and odd runs okay + + + align:start position:0% +scenes and odd runs okay +so then + + align:start position:0% +so then + + + align:start position:0% +so then +once we have those four patterns what is + + align:start position:0% +once we have those four patterns what is + + + align:start position:0% +once we have those four patterns what is +the key prediction + + align:start position:0% +the key prediction + + + align:start position:0% +the key prediction +if uh using haxby's correlation method + + align:start position:0% +if uh using haxby's correlation method + + + align:start position:0% +if uh using haxby's correlation method +what is the key prediction if the ppa + + align:start position:0% +what is the key prediction if the ppa + + + align:start position:0% +what is the key prediction if the ppa +if pattern of response in the ppa can + + align:start position:0% +if pattern of response in the ppa can + + + align:start position:0% +if pattern of response in the ppa can +discriminate beach scenes from city + + align:start position:0% +discriminate beach scenes from city + + + align:start position:0% +discriminate beach scenes from city +scenes what should we see from these + + align:start position:0% +scenes what should we see from these + + + align:start position:0% +scenes what should we see from these +patterns what's the key prediction + + align:start position:0% + + + + align:start position:0% + +claire + + align:start position:0% + + + + align:start position:0% + +key prediction you have these four + + align:start position:0% +key prediction you have these four + + + align:start position:0% +key prediction you have these four +patterns + + align:start position:0% +patterns + + + align:start position:0% +patterns +in the ppa and now you want to know is + + align:start position:0% +in the ppa and now you want to know is + + + align:start position:0% +in the ppa and now you want to know is +there information in there + + align:start position:0% +there information in there + + + align:start position:0% +there information in there +that enables you to discriminate beach + + align:start position:0% +that enables you to discriminate beach + + + align:start position:0% +that enables you to discriminate beach +scenes from city scenes is that like + + align:start position:0% +scenes from city scenes is that like + + + align:start position:0% +scenes from city scenes is that like +beach even in the beach odd or less than + + align:start position:0% +beach even in the beach odd or less than + + + align:start position:0% +beach even in the beach odd or less than +the achievement city + + align:start position:0% +the achievement city + + + align:start position:0% +the achievement city +exactly exactly right it's actually you + + align:start position:0% +exactly exactly right it's actually you + + + align:start position:0% +exactly exactly right it's actually you +know it sounds all like complicated it's + + align:start position:0% +know it sounds all like complicated it's + + + align:start position:0% +know it sounds all like complicated it's +easy to get confused but the nub of the + + align:start position:0% +easy to get confused but the nub of the + + + align:start position:0% +easy to get confused but the nub of the +idea is really simple it just says look + + align:start position:0% +idea is really simple it just says look + + + align:start position:0% +idea is really simple it just says look +the beach patterns are stable we do + + align:start position:0% +the beach patterns are stable we do + + + align:start position:0% +the beach patterns are stable we do +beach a few times we get the same + + align:start position:0% +beach a few times we get the same + + + align:start position:0% +beach a few times we get the same +pattern more or less + + align:start position:0% +pattern more or less + + + align:start position:0% +pattern more or less +we do city we get a different pattern + + align:start position:0% +we do city we get a different pattern + + + align:start position:0% +we do city we get a different pattern +and we keep doing city we get the same + + align:start position:0% +and we keep doing city we get the same + + + align:start position:0% +and we keep doing city we get the same +pattern more or less and the beach + + align:start position:0% +pattern more or less and the beach + + + align:start position:0% +pattern more or less and the beach +pattern and the city pattern are + + align:start position:0% +pattern and the city pattern are + + + align:start position:0% +pattern and the city pattern are +different + + align:start position:0% +different + + + align:start position:0% +different +so that's the nova the idea and so you + + align:start position:0% +so that's the nova the idea and so you + + + align:start position:0% +so that's the nova the idea and so you +can implement it with decoding methods + + align:start position:0% +can implement it with decoding methods + + + align:start position:0% +can implement it with decoding methods +or the hacks b versions just to ask + + align:start position:0% +or the hacks b versions just to ask + + + align:start position:0% +or the hacks b versions just to ask +whether the correlation between + + align:start position:0% +whether the correlation between + + + align:start position:0% +whether the correlation between +two beach patterns beach even beach odd + + align:start position:0% +two beach patterns beach even beach odd + + + align:start position:0% +two beach patterns beach even beach odd +is more similar than the pattern between + + align:start position:0% +is more similar than the pattern between + + + align:start position:0% +is more similar than the pattern between +one of the beaches and one of the cities + + align:start position:0% +one of the beaches and one of the cities + + + align:start position:0% +one of the beaches and one of the cities +okay + + align:start position:0% +okay + + + align:start position:0% +okay +just asking are they more are they + + align:start position:0% +just asking are they more are they + + + align:start position:0% +just asking are they more are they +stably similar within a category and + + align:start position:0% +stably similar within a category and + + + align:start position:0% +stably similar within a category and +stably different from another category + + align:start position:0% +stably different from another category + + + align:start position:0% +stably different from another category +does that make sense okay + + align:start position:0% +does that make sense okay + + + align:start position:0% +does that make sense okay +um boom this is just so it's just a + + align:start position:0% +um boom this is just so it's just a + + + align:start position:0% +um boom this is just so it's just a +variant of this thing i showed you guys + + align:start position:0% +variant of this thing i showed you guys + + + align:start position:0% +variant of this thing i showed you guys +before we just harness this to + + align:start position:0% +before we just harness this to + + + align:start position:0% +before we just harness this to +to ask whether that region can + + align:start position:0% +to ask whether that region can + + + align:start position:0% +to ask whether that region can +discriminate okay and i just said all of + + align:start position:0% +discriminate okay and i just said all of + + + align:start position:0% +discriminate okay and i just said all of +this + + align:start position:0% +this + + + align:start position:0% +this +okay if you still feel shaky on this + + align:start position:0% +okay if you still feel shaky on this + + + align:start position:0% +okay if you still feel shaky on this +there's a few things you can do um a + + align:start position:0% +there's a few things you can do um a + + + align:start position:0% +there's a few things you can do um a +version of my little lecture on on this + + align:start position:0% +version of my little lecture on on this + + + align:start position:0% +version of my little lecture on on this +method is here at the on my website you + + align:start position:0% +method is here at the on my website you + + + align:start position:0% +method is here at the on my website you +can look at that it's just like six + + align:start position:0% +can look at that it's just like six + + + align:start position:0% +can look at that it's just like six +minutes and it's basically what i did + + align:start position:0% +minutes and it's basically what i did + + + align:start position:0% +minutes and it's basically what i did +before but if you want to go over it + + align:start position:0% +before but if you want to go over it + + + align:start position:0% +before but if you want to go over it +again there it is + + align:start position:0% +again there it is + + + align:start position:0% +again there it is +you can reread the hacksby paper which i + + align:start position:0% +you can reread the hacksby paper which i + + + align:start position:0% +you can reread the hacksby paper which i +know is not super easy but it's actually + + align:start position:0% +know is not super easy but it's actually + + + align:start position:0% +know is not super easy but it's actually +nicely written and if you read it + + align:start position:0% +nicely written and if you read it + + + align:start position:0% +nicely written and if you read it +carefully it explains the method pretty + + align:start position:0% +carefully it explains the method pretty + + + align:start position:0% +carefully it explains the method pretty +clearly you can talk to me or a ta + + align:start position:0% +clearly you can talk to me or a ta + + + align:start position:0% +clearly you can talk to me or a ta +and we'll get back to this question of + + align:start position:0% +and we'll get back to this question of + + + align:start position:0% +and we'll get back to this question of +whether we should do a whole matlab + + align:start position:0% +whether we should do a whole matlab + + + align:start position:0% +whether we should do a whole matlab +based problem set on this + + align:start position:0% +based problem set on this + + + align:start position:0% +based problem set on this +all right + + align:start position:0% +all right + + + align:start position:0% +all right +okay let's move on and talk about + + align:start position:0% +okay let's move on and talk about + + + align:start position:0% +okay let's move on and talk about +navigation + + align:start position:0% + + + + align:start position:0% + +okay this is a monarch butterfly + + align:start position:0% +okay this is a monarch butterfly + + + align:start position:0% +okay this is a monarch butterfly +it weighs about half a gram + + align:start position:0% +it weighs about half a gram + + + align:start position:0% +it weighs about half a gram +and yet + + align:start position:0% +and yet + + + align:start position:0% +and yet +each fall + + align:start position:0% +each fall + + + align:start position:0% +each fall +the monarch migrates over 2000 miles + + align:start position:0% +the monarch migrates over 2000 miles + + + align:start position:0% +the monarch migrates over 2000 miles +from the usa in canada down to mexico + + align:start position:0% +from the usa in canada down to mexico + + + align:start position:0% +from the usa in canada down to mexico +in fact it migrates + + align:start position:0% +in fact it migrates + + + align:start position:0% +in fact it migrates +it fly a single monarch flies 50 miles + + align:start position:0% +it fly a single monarch flies 50 miles + + + align:start position:0% +it fly a single monarch flies 50 miles +in a single day it's pretty amazing for + + align:start position:0% +in a single day it's pretty amazing for + + + align:start position:0% +in a single day it's pretty amazing for +this tiny little beautiful delicate + + align:start position:0% +this tiny little beautiful delicate + + + align:start position:0% +this tiny little beautiful delicate +thing + + align:start position:0% +thing + + + align:start position:0% +thing +even more amazing it flies to a very + + align:start position:0% +even more amazing it flies to a very + + + align:start position:0% +even more amazing it flies to a very +specific forest in mexico that's just a + + align:start position:0% +specific forest in mexico that's just a + + + align:start position:0% +specific forest in mexico that's just a +few acres in size and it arrives at that + + align:start position:0% +few acres in size and it arrives at that + + + align:start position:0% +few acres in size and it arrives at that +particular forest + + align:start position:0% +particular forest + + + align:start position:0% +particular forest +now that's already amazing but here's + + align:start position:0% +now that's already amazing but here's + + + align:start position:0% +now that's already amazing but here's +the part that is just totally + + align:start position:0% +the part that is just totally + + + align:start position:0% +the part that is just totally +mind-blowing + + align:start position:0% +mind-blowing + + + align:start position:0% +mind-blowing +and that is + + align:start position:0% +and that is + + + align:start position:0% +and that is +and it flies back north in the spring + + align:start position:0% +and it flies back north in the spring + + + align:start position:0% +and it flies back north in the spring +and that is that this whole cycle + + align:start position:0% +and that is that this whole cycle + + + align:start position:0% +and that is that this whole cycle +takes four generations to complete + + align:start position:0% +takes four generations to complete + + + align:start position:0% +takes four generations to complete +and that means that the monarch that + + align:start position:0% +and that means that the monarch that + + + align:start position:0% +and that means that the monarch that +starts up in canada and flies down to + + align:start position:0% +starts up in canada and flies down to + + + align:start position:0% +starts up in canada and flies down to +that forest in mexico one monarch does + + align:start position:0% +that forest in mexico one monarch does + + + align:start position:0% +that forest in mexico one monarch does +that + + align:start position:0% +that + + + align:start position:0% +that +is the great great grandkid + + align:start position:0% +is the great great grandkid + + + align:start position:0% +is the great great grandkid +of his ancestor that last went on that + + align:start position:0% +of his ancestor that last went on that + + + align:start position:0% +of his ancestor that last went on that +route + + align:start position:0% +route + + + align:start position:0% +route +put that in your head and smoke it + + align:start position:0% +put that in your head and smoke it + + + align:start position:0% +put that in your head and smoke it +that's pretty amazing + + align:start position:0% +that's pretty amazing + + + align:start position:0% +that's pretty amazing +okay + + align:start position:0% +okay + + + align:start position:0% +okay +all right + + align:start position:0% + + + + align:start position:0% + +consider the female loggerhead turtle + + align:start position:0% +consider the female loggerhead turtle + + + align:start position:0% +consider the female loggerhead turtle +she um hatches at a beach and goes out + + align:start position:0% +she um hatches at a beach and goes out + + + align:start position:0% +she um hatches at a beach and goes out +in the sea + + align:start position:0% +in the sea + + + align:start position:0% +in the sea +and swims around in the sea for 20 years + + align:start position:0% +and swims around in the sea for 20 years + + + align:start position:0% +and swims around in the sea for 20 years +before she comes back 20 years later for + + align:start position:0% +before she comes back 20 years later for + + + align:start position:0% +before she comes back 20 years later for +the first time to the beach that she + + align:start position:0% +the first time to the beach that she + + + align:start position:0% +the first time to the beach that she +hatched at + + align:start position:0% +hatched at + + + align:start position:0% +hatched at +okay + + align:start position:0% + + + + align:start position:0% + +now it's pretty amazing but some mothers + + align:start position:0% +now it's pretty amazing but some mothers + + + align:start position:0% +now it's pretty amazing but some mothers +miss by 20 miles they go to the wrong + + align:start position:0% +miss by 20 miles they go to the wrong + + + align:start position:0% +miss by 20 miles they go to the wrong +island or the wrong beach on the same + + align:start position:0% +island or the wrong beach on the same + + + align:start position:0% +island or the wrong beach on the same +island okay + + align:start position:0% +island okay + + + align:start position:0% +island okay +and so + + align:start position:0% +and so + + + align:start position:0% +and so +you might think okay it's pretty good + + align:start position:0% +you might think okay it's pretty good + + + align:start position:0% +you might think okay it's pretty good +it's not amazing + + align:start position:0% +it's not amazing + + + align:start position:0% +it's not amazing +but here's the thing + + align:start position:0% +but here's the thing + + + align:start position:0% +but here's the thing +the wrong beach that those mothers go to + + align:start position:0% +the wrong beach that those mothers go to + + + align:start position:0% +the wrong beach that those mothers go to +is the exactly right beach had the + + align:start position:0% +is the exactly right beach had the + + + align:start position:0% +is the exactly right beach had the +earth's magnetic field not shifted + + align:start position:0% +earth's magnetic field not shifted + + + align:start position:0% +earth's magnetic field not shifted +slightly over those 20 years + + align:start position:0% +slightly over those 20 years + + + align:start position:0% +slightly over those 20 years +they're exactly precise + + align:start position:0% +they're exactly precise + + + align:start position:0% +they're exactly precise +but they just don't compensate for the + + align:start position:0% +but they just don't compensate for the + + + align:start position:0% +but they just don't compensate for the +shift in the earth's magnetic field + + align:start position:0% + + + + align:start position:0% + +here's a bat + + align:start position:0% +here's a bat + + + align:start position:0% +here's a bat +this bat + + align:start position:0% +this bat + + + align:start position:0% +this bat +maintains its sense of direction + + align:start position:0% +maintains its sense of direction + + + align:start position:0% +maintains its sense of direction +even while it flies 30 to 50 miles in a + + align:start position:0% +even while it flies 30 to 50 miles in a + + + align:start position:0% +even while it flies 30 to 50 miles in a +single night in the dark + + align:start position:0% +single night in the dark + + + align:start position:0% +single night in the dark +catching food + + align:start position:0% +catching food + + + align:start position:0% +catching food +okay and it maintains its sense of + + align:start position:0% +okay and it maintains its sense of + + + align:start position:0% +okay and it maintains its sense of +direction even though it's flying around + + align:start position:0% +direction even though it's flying around + + + align:start position:0% +direction even though it's flying around +in all different orientations in three + + align:start position:0% +in all different orientations in three + + + align:start position:0% +in all different orientations in three +dimensions + + align:start position:0% +dimensions + + + align:start position:0% +dimensions +and even as it flips over and lands + + align:start position:0% +and even as it flips over and lands + + + align:start position:0% +and even as it flips over and lands +to + + align:start position:0% +to + + + align:start position:0% +to +perch on the surface of a cave + + align:start position:0% +perch on the surface of a cave + + + align:start position:0% +perch on the surface of a cave +doesn't get confused by being upside + + align:start position:0% +doesn't get confused by being upside + + + align:start position:0% +doesn't get confused by being upside +down + + align:start position:0% +down + + + align:start position:0% +down +okay + + align:start position:0% + + + + align:start position:0% + +this is cataglyphus the tunisian desert + + align:start position:0% +this is cataglyphus the tunisian desert + + + align:start position:0% +this is cataglyphus the tunisian desert +ant these guys are amazing they crawl + + align:start position:0% +ant these guys are amazing they crawl + + + align:start position:0% +ant these guys are amazing they crawl +around on the surface of the tunisian + + align:start position:0% +around on the surface of the tunisian + + + align:start position:0% +around on the surface of the tunisian +desert where it's 140 degrees in the + + align:start position:0% +desert where it's 140 degrees in the + + + align:start position:0% +desert where it's 140 degrees in the +daytime + + align:start position:0% +daytime + + + align:start position:0% +daytime +they have to crawl around up there to + + align:start position:0% +they have to crawl around up there to + + + align:start position:0% +they have to crawl around up there to +forage for food + + align:start position:0% +forage for food + + + align:start position:0% +forage for food +and then because it's so damn hot as + + align:start position:0% +and then because it's so damn hot as + + + align:start position:0% +and then because it's so damn hot as +soon as they find food they zoom back to + + align:start position:0% +soon as they find food they zoom back to + + + align:start position:0% +soon as they find food they zoom back to +their nest and go down in the nest where + + align:start position:0% +their nest and go down in the nest where + + + align:start position:0% +their nest and go down in the nest where +it's cooler + + align:start position:0% +it's cooler + + + align:start position:0% +it's cooler +so here is a track of cataglyphus + + align:start position:0% +so here is a track of cataglyphus + + + align:start position:0% +so here is a track of cataglyphus +starting at point a + + align:start position:0% +starting at point a + + + align:start position:0% +starting at point a +and foraging he's meandering around + + align:start position:0% +and foraging he's meandering around + + + align:start position:0% +and foraging he's meandering around +looking for food going along this whole + + align:start position:0% +looking for food going along this whole + + + align:start position:0% +looking for food going along this whole +crazy path to point b + + align:start position:0% +crazy path to point b + + + align:start position:0% +crazy path to point b +and then if he finds food at point b + + align:start position:0% +and then if he finds food at point b + + + align:start position:0% +and then if he finds food at point b +boom + + align:start position:0% +boom + + + align:start position:0% +boom +straight line back exactly to the nest + + align:start position:0% +straight line back exactly to the nest + + + align:start position:0% +straight line back exactly to the nest +now we might ask how does cataglyphus + + align:start position:0% +now we might ask how does cataglyphus + + + align:start position:0% +now we might ask how does cataglyphus +keep track because he's doing all this + + align:start position:0% +keep track because he's doing all this + + + align:start position:0% +keep track because he's doing all this +stuff + + align:start position:0% +stuff + + + align:start position:0% +stuff +of where his heading is back to his nest + + align:start position:0% +of where his heading is back to his nest + + + align:start position:0% +of where his heading is back to his nest +okay + + align:start position:0% +okay + + + align:start position:0% +okay +the first thing you might think of is + + align:start position:0% +the first thing you might think of is + + + align:start position:0% +the first thing you might think of is +things like what it looks like maybe + + align:start position:0% +things like what it looks like maybe + + + align:start position:0% +things like what it looks like maybe +their landmarks maybe their odors maybe + + align:start position:0% +their landmarks maybe their odors maybe + + + align:start position:0% +their landmarks maybe their odors maybe +their odors + + align:start position:0% +their odors + + + align:start position:0% +their odors +but no + + align:start position:0% +but no + + + align:start position:0% +but no +he doesn't use any of those things and + + align:start position:0% +he doesn't use any of those things and + + + align:start position:0% +he doesn't use any of those things and +we know that + + align:start position:0% +we know that + + + align:start position:0% +we know that +because when scientists who have set up + + align:start position:0% +because when scientists who have set up + + + align:start position:0% +because when scientists who have set up +this measurement device + + align:start position:0% +this measurement device + + + align:start position:0% +this measurement device +capture cataglyphus after he goes out on + + align:start position:0% +capture cataglyphus after he goes out on + + + align:start position:0% +capture cataglyphus after he goes out on +this tortuous path and finds the feeding + + align:start position:0% +this tortuous path and finds the feeding + + + align:start position:0% +this tortuous path and finds the feeding +station they capture him and move them + + align:start position:0% +station they capture him and move them + + + align:start position:0% +station they capture him and move them +across the desert on which they've drawn + + align:start position:0% +across the desert on which they've drawn + + + align:start position:0% +across the desert on which they've drawn +all these grid lines for the convenience + + align:start position:0% +all these grid lines for the convenience + + + align:start position:0% +all these grid lines for the convenience +of their experiment and they release him + + align:start position:0% +of their experiment and they release him + + + align:start position:0% +of their experiment and they release him +here and what does cataglyphus do + + align:start position:0% +here and what does cataglyphus do + + + align:start position:0% +here and what does cataglyphus do +he goes on the exactly correct vector + + align:start position:0% + + + + align:start position:0% + +no landmarks no relevant odors + + align:start position:0% +no landmarks no relevant odors + + + align:start position:0% +no landmarks no relevant odors +and yet he's obviously encoded the exact + + align:start position:0% +and yet he's obviously encoded the exact + + + align:start position:0% +and yet he's obviously encoded the exact +vector of how to get home + + align:start position:0% +vector of how to get home + + + align:start position:0% +vector of how to get home +think about what that entails and what's + + align:start position:0% +think about what that entails and what's + + + align:start position:0% +think about what that entails and what's +involved + + align:start position:0% +involved + + + align:start position:0% +involved +okay the same vector with respect to + + align:start position:0% +okay the same vector with respect to + + + align:start position:0% +okay the same vector with respect to +north with respect to this yes yes well + + align:start position:0% +north with respect to this yes yes well + + + align:start position:0% +north with respect to this yes yes well +with respect to like absolute + + align:start position:0% +with respect to like absolute + + + align:start position:0% +with respect to like absolute +um external direction absolutely + + align:start position:0% +um external direction absolutely + + + align:start position:0% +um external direction absolutely +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so that's what i just said + + align:start position:0% +so that's what i just said + + + align:start position:0% +so that's what i just said +so these feats of animal navigation + + align:start position:0% +so these feats of animal navigation + + + align:start position:0% +so these feats of animal navigation +uh are amazing + + align:start position:0% +uh are amazing + + + align:start position:0% +uh are amazing +um and animals have evolved ways to + + align:start position:0% +um and animals have evolved ways to + + + align:start position:0% +um and animals have evolved ways to +solve all these problems unique to their + + align:start position:0% +solve all these problems unique to their + + + align:start position:0% +solve all these problems unique to their +environment + + align:start position:0% +environment + + + align:start position:0% +environment +they've evolved these + + align:start position:0% +they've evolved these + + + align:start position:0% +they've evolved these +abilities because they really have to be + + align:start position:0% +abilities because they really have to be + + + align:start position:0% +abilities because they really have to be +able to find food + + align:start position:0% +able to find food + + + align:start position:0% +able to find food +and mates + + align:start position:0% +and mates + + + align:start position:0% +and mates +and shelter + + align:start position:0% +and shelter + + + align:start position:0% +and shelter +and this is not just esoterica in the + + align:start position:0% +and this is not just esoterica in the + + + align:start position:0% +and this is not just esoterica in the +natural world + + align:start position:0% +natural world + + + align:start position:0% +natural world +mit students too need to be able to find + + align:start position:0% +mit students too need to be able to find + + + align:start position:0% +mit students too need to be able to find +food + + align:start position:0% +food + + + align:start position:0% +food +and mates + + align:start position:0% +and mates + + + align:start position:0% +and mates +and shelter + + align:start position:0% +and shelter + + + align:start position:0% +and shelter +so + + align:start position:0% +so + + + align:start position:0% +so +what is navigation anyway uh and what + + align:start position:0% +what is navigation anyway uh and what + + + align:start position:0% +what is navigation anyway uh and what +does it entail + + align:start position:0% +does it entail + + + align:start position:0% +does it entail +uh well i'll argue over the next two + + align:start position:0% +uh well i'll argue over the next two + + + align:start position:0% +uh well i'll argue over the next two +lectures that there are two fundamental + + align:start position:0% +lectures that there are two fundamental + + + align:start position:0% +lectures that there are two fundamental +questions that organisms need to solve + + align:start position:0% +questions that organisms need to solve + + + align:start position:0% +questions that organisms need to solve +to be able to navigate first one is + + align:start position:0% +to be able to navigate first one is + + + align:start position:0% +to be able to navigate first one is +where am i + + align:start position:0% +where am i + + + align:start position:0% +where am i +and the second one is how do i get from + + align:start position:0% +and the second one is how do i get from + + + align:start position:0% +and the second one is how do i get from +here to there a to b wherever there is + + align:start position:0% +here to there a to b wherever there is + + + align:start position:0% +here to there a to b wherever there is +that you need to get + + align:start position:0% +that you need to get + + + align:start position:0% +that you need to get +okay so we'll unpack this or many + + align:start position:0% +okay so we'll unpack this or many + + + align:start position:0% +okay so we'll unpack this or many +different facets of each + + align:start position:0% +different facets of each + + + align:start position:0% +different facets of each +but so for example + + align:start position:0% +but so for example + + + align:start position:0% +but so for example +if you see this image + + align:start position:0% +if you see this image + + + align:start position:0% +if you see this image +you immediately know + + align:start position:0% +you immediately know + + + align:start position:0% +you immediately know +where you are + + align:start position:0% +where you are + + + align:start position:0% +where you are +and you also know + + align:start position:0% +and you also know + + + align:start position:0% +and you also know +where to go if for example it starts + + align:start position:0% +where to go if for example it starts + + + align:start position:0% +where to go if for example it starts +raining + + align:start position:0% +raining + + + align:start position:0% +raining +you might rush into lobby 7. + + align:start position:0% +you might rush into lobby 7. + + + align:start position:0% +you might rush into lobby 7. +or if you're hungry you might turn + + align:start position:0% +or if you're hungry you might turn + + + align:start position:0% +or if you're hungry you might turn +around and go back to the student center + + align:start position:0% +around and go back to the student center + + + align:start position:0% +around and go back to the student center +right + + align:start position:0% +right + + + align:start position:0% +right +same deal here if you see this + + align:start position:0% +same deal here if you see this + + + align:start position:0% +same deal here if you see this +then you know where you are and where + + align:start position:0% +then you know where you are and where + + + align:start position:0% +then you know where you are and where +you would go to get to various things + + align:start position:0% +you would go to get to various things + + + align:start position:0% +you would go to get to various things +okay now these judgments rely on the + + align:start position:0% +okay now these judgments rely on the + + + align:start position:0% +okay now these judgments rely on the +specific knowledge you you guys have of + + align:start position:0% +specific knowledge you you guys have of + + + align:start position:0% +specific knowledge you you guys have of +those particular places you recognize + + align:start position:0% +those particular places you recognize + + + align:start position:0% +those particular places you recognize +that exact place and you know + + align:start position:0% +that exact place and you know + + + align:start position:0% +that exact place and you know +you have some kind of map in your head + + align:start position:0% +you have some kind of map in your head + + + align:start position:0% +you have some kind of map in your head +that we'll talk more about in a moment + + align:start position:0% +that we'll talk more about in a moment + + + align:start position:0% +that we'll talk more about in a moment +that tells you where everything else is + + align:start position:0% +that tells you where everything else is + + + align:start position:0% +that tells you where everything else is +with respect to it + + align:start position:0% +with respect to it + + + align:start position:0% +with respect to it +but even if you're in a place you don't + + align:start position:0% +but even if you're in a place you don't + + + align:start position:0% +but even if you're in a place you don't +know at all + + align:start position:0% +know at all + + + align:start position:0% +know at all +you can still extract some information + + align:start position:0% +you can still extract some information + + + align:start position:0% +you can still extract some information +so suppose you miraculously found + + align:start position:0% +so suppose you miraculously found + + + align:start position:0% +so suppose you miraculously found +yourself boom here + + align:start position:0% +yourself boom here + + + align:start position:0% +yourself boom here +i wouldn't mind actually but that's not + + align:start position:0% +i wouldn't mind actually but that's not + + + align:start position:0% +i wouldn't mind actually but that's not +in the cards for a while + + align:start position:0% +in the cards for a while + + + align:start position:0% +in the cards for a while +um so you're here + + align:start position:0% +um so you're here + + + align:start position:0% +um so you're here +even if you've just hiked around the + + align:start position:0% +even if you've just hiked around the + + + align:start position:0% +even if you've just hiked around the +corner if you've never seen this place + + align:start position:0% +corner if you've never seen this place + + + align:start position:0% +corner if you've never seen this place +before + + align:start position:0% +before + + + align:start position:0% +before +you have some kind of idea what sort of + + align:start position:0% +you have some kind of idea what sort of + + + align:start position:0% +you have some kind of idea what sort of +place this is where would you pitch your + + align:start position:0% +place this is where would you pitch your + + + align:start position:0% +place this is where would you pitch your +tent + + align:start position:0% +tent + + + align:start position:0% +tent +you know where might you try to go to + + align:start position:0% +you know where might you try to go to + + + align:start position:0% +you know where might you try to go to +get out of this valley if it was me i + + align:start position:0% +get out of this valley if it was me i + + + align:start position:0% +get out of this valley if it was me i +wouldn't i have friends who would go + + align:start position:0% +wouldn't i have friends who would go + + + align:start position:0% +wouldn't i have friends who would go +straight up there and try to drag me + + align:start position:0% +straight up there and try to drag me + + + align:start position:0% +straight up there and try to drag me +along complaining if it was me i'd + + align:start position:0% +along complaining if it was me i'd + + + align:start position:0% +along complaining if it was me i'd +rather look for some other route + + align:start position:0% +rather look for some other route + + + align:start position:0% +rather look for some other route +but you can tell all of that just by + + align:start position:0% +but you can tell all of that just by + + + align:start position:0% +but you can tell all of that just by +looking at this image + + align:start position:0% +looking at this image + + + align:start position:0% +looking at this image +okay okay where you can go from there + + align:start position:0% +okay okay where you can go from there + + + align:start position:0% +okay okay where you can go from there +not just what kind of a place it is but + + align:start position:0% +not just what kind of a place it is but + + + align:start position:0% +not just what kind of a place it is but +what are the possible routes you might + + align:start position:0% +what are the possible routes you might + + + align:start position:0% +what are the possible routes you might +take + + align:start position:0% +take + + + align:start position:0% +take +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so these fundamental problems that we + + align:start position:0% +so these fundamental problems that we + + + align:start position:0% +so these fundamental problems that we +solve in navigation of knowing where am + + align:start position:0% +solve in navigation of knowing where am + + + align:start position:0% +solve in navigation of knowing where am +i and how do i get from here to there + + align:start position:0% +i and how do i get from here to there + + + align:start position:0% +i and how do i get from here to there +include multiple components in terms of + + align:start position:0% +include multiple components in terms of + + + align:start position:0% +include multiple components in terms of +where am i the first the first piece is + + align:start position:0% +where am i the first the first piece is + + + align:start position:0% +where am i the first the first piece is +recognizing a specific place you know + + align:start position:0% +recognizing a specific place you know + + + align:start position:0% +recognizing a specific place you know +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so you might open your eyes and say okay + + align:start position:0% +so you might open your eyes and say okay + + + align:start position:0% +so you might open your eyes and say okay +this is my living room i know this + + align:start position:0% +this is my living room i know this + + + align:start position:0% +this is my living room i know this +particular place + + align:start position:0% +particular place + + + align:start position:0% +particular place +okay + + align:start position:0% +okay + + + align:start position:0% +okay +but as i just pointed out even if the + + align:start position:0% +but as i just pointed out even if the + + + align:start position:0% +but as i just pointed out even if the +place is unfamiliar + + align:start position:0% +place is unfamiliar + + + align:start position:0% +place is unfamiliar +we can get a sense of what kind of place + + align:start position:0% +we can get a sense of what kind of place + + + align:start position:0% +we can get a sense of what kind of place +this is right am i in an urban + + align:start position:0% +this is right am i in an urban + + + align:start position:0% +this is right am i in an urban +environment a natural environment a + + align:start position:0% +environment a natural environment a + + + align:start position:0% +environment a natural environment a +living room a bathroom where am + + align:start position:0% +living room a bathroom where am + + + align:start position:0% +living room a bathroom where am +i a third aspect of where am i a third + + align:start position:0% +i a third aspect of where am i a third + + + align:start position:0% +i a third aspect of where am i a third +way that we might answer that question + + align:start position:0% +way that we might answer that question + + + align:start position:0% +way that we might answer that question +is something about the geometry of the + + align:start position:0% +is something about the geometry of the + + + align:start position:0% +is something about the geometry of the +environment we're in + + align:start position:0% +environment we're in + + + align:start position:0% +environment we're in +so try this right now close your eyes + + align:start position:0% +so try this right now close your eyes + + + align:start position:0% +so try this right now close your eyes +okay now think about how far the wall is + + align:start position:0% +okay now think about how far the wall is + + + align:start position:0% +okay now think about how far the wall is +in front of you don't open your eyes + + align:start position:0% +in front of you don't open your eyes + + + align:start position:0% +in front of you don't open your eyes +just think about how far away it is how + + align:start position:0% +just think about how far away it is how + + + align:start position:0% +just think about how far away it is how +far away the left wall is and the right + + align:start position:0% +far away the left wall is and the right + + + align:start position:0% +far away the left wall is and the right +wall is and how about the wall behind + + align:start position:0% +wall is and how about the wall behind + + + align:start position:0% +wall is and how about the wall behind +you don't open your eyes how far back is + + align:start position:0% +you don't open your eyes how far back is + + + align:start position:0% +you don't open your eyes how far back is +the wall behind you from where you are + + align:start position:0% +the wall behind you from where you are + + + align:start position:0% +the wall behind you from where you are +right now + + align:start position:0% +right now + + + align:start position:0% +right now +okay you can open your eyes it's not + + align:start position:0% +okay you can open your eyes it's not + + + align:start position:0% +okay you can open your eyes it's not +rocket science i just wanted you to + + align:start position:0% +rocket science i just wanted you to + + + align:start position:0% +rocket science i just wanted you to +intuit that even though you're + + align:start position:0% +intuit that even though you're + + + align:start position:0% +intuit that even though you're +presumably riveted by this lecture and + + align:start position:0% +presumably riveted by this lecture and + + + align:start position:0% +presumably riveted by this lecture and +thinking only about navigation you sort + + align:start position:0% +thinking only about navigation you sort + + + align:start position:0% +thinking only about navigation you sort +of have a kind of situational awareness + + align:start position:0% +of have a kind of situational awareness + + + align:start position:0% +of have a kind of situational awareness +of the spatial layout of the space + + align:start position:0% +of the spatial layout of the space + + + align:start position:0% +of the spatial layout of the space +you're in + + align:start position:0% +you're in + + + align:start position:0% +you're in +so + + align:start position:0% +so + + + align:start position:0% +so +you might have a sense of okay i'm in a + + align:start position:0% +you might have a sense of okay i'm in a + + + align:start position:0% +you might have a sense of okay i'm in a +space like this and i'm over here in it + + align:start position:0% +space like this and i'm over here in it + + + align:start position:0% +space like this and i'm over here in it +right + + align:start position:0% +right + + + align:start position:0% +right +and we'll talk more about that exact + + align:start position:0% +and we'll talk more about that exact + + + align:start position:0% +and we'll talk more about that exact +kind of awareness of your position + + align:start position:0% +kind of awareness of your position + + + align:start position:0% +kind of awareness of your position +relative to the spatial layout of your + + align:start position:0% +relative to the spatial layout of your + + + align:start position:0% +relative to the spatial layout of your +immediate environment it's something + + align:start position:0% +immediate environment it's something + + + align:start position:0% +immediate environment it's something +that's very important in navigation + + align:start position:0% +that's very important in navigation + + + align:start position:0% +that's very important in navigation +and another part of that is you might + + align:start position:0% +and another part of that is you might + + + align:start position:0% +and another part of that is you might +think how would i get out of here if i'm + + align:start position:0% +think how would i get out of here if i'm + + + align:start position:0% +think how would i get out of here if i'm +seriously bored by the lecture or for + + align:start position:0% +seriously bored by the lecture or for + + + align:start position:0% +seriously bored by the lecture or for +any other reason i urgently need to get + + align:start position:0% +any other reason i urgently need to get + + + align:start position:0% +any other reason i urgently need to get +out of here you probably know exactly + + align:start position:0% +out of here you probably know exactly + + + align:start position:0% +out of here you probably know exactly +where the doors are in this space it's + + align:start position:0% +where the doors are in this space it's + + + align:start position:0% +where the doors are in this space it's +just part of those one of those things + + align:start position:0% +just part of those one of those things + + + align:start position:0% +just part of those one of those things +that we + + align:start position:0% +that we + + + align:start position:0% +that we +keep track of okay + + align:start position:0% +keep track of okay + + + align:start position:0% +keep track of okay +okay so those are aspects of where am i + + align:start position:0% +okay so those are aspects of where am i + + + align:start position:0% +okay so those are aspects of where am i +in this place + + align:start position:0% +in this place + + + align:start position:0% +in this place +what are the things we need to know to + + align:start position:0% +what are the things we need to know to + + + align:start position:0% +what are the things we need to know to +know how we would get from here to + + align:start position:0% +know how we would get from here to + + + align:start position:0% +know how we would get from here to +someplace else + + align:start position:0% +someplace else + + + align:start position:0% +someplace else +okay well the simplest way to navigate + + align:start position:0% +okay well the simplest way to navigate + + + align:start position:0% +okay well the simplest way to navigate +to another location another goal is + + align:start position:0% +to another location another goal is + + + align:start position:0% +to another location another goal is +called beaconing and this is the case + + align:start position:0% +called beaconing and this is the case + + + align:start position:0% +called beaconing and this is the case +where you can directly see or hear your + + align:start position:0% +where you can directly see or hear your + + + align:start position:0% +where you can directly see or hear your +target location so you're sailing in the + + align:start position:0% +target location so you're sailing in the + + + align:start position:0% +target location so you're sailing in the +fog you can't see a damn thing but you + + align:start position:0% +fog you can't see a damn thing but you + + + align:start position:0% +fog you can't see a damn thing but you +hear the fog horn over there and you + + align:start position:0% +hear the fog horn over there and you + + + align:start position:0% +hear the fog horn over there and you +know you're sailing to that point so you + + align:start position:0% +know you're sailing to that point so you + + + align:start position:0% +know you're sailing to that point so you +just go toward the sound + + align:start position:0% +just go toward the sound + + + align:start position:0% +just go toward the sound +nice and simple you don't need any + + align:start position:0% +nice and simple you don't need any + + + align:start position:0% +nice and simple you don't need any +broader map of anything else you just + + align:start position:0% +broader map of anything else you just + + + align:start position:0% +broader map of anything else you just +hear it and head toward it + + align:start position:0% + + + + align:start position:0% + +or + + align:start position:0% +or + + + align:start position:0% +or +if you see this + + align:start position:0% +if you see this + + + align:start position:0% +if you see this +and your goal is to get to the green + + align:start position:0% +and your goal is to get to the green + + + align:start position:0% +and your goal is to get to the green +building + + align:start position:0% +building + + + align:start position:0% +building +well you know there's a green building + + align:start position:0% +well you know there's a green building + + + align:start position:0% +well you know there's a green building +and you just head that way now you're + + align:start position:0% +and you just head that way now you're + + + align:start position:0% +and you just head that way now you're +gonna have to like go around a little + + align:start position:0% +gonna have to like go around a little + + + align:start position:0% +gonna have to like go around a little +bit to get around those obstacles but + + align:start position:0% +bit to get around those obstacles but + + + align:start position:0% +bit to get around those obstacles but +you know where to head because you can + + align:start position:0% +you know where to head because you can + + + align:start position:0% +you know where to head because you can +see your target directly okay these are + + align:start position:0% +see your target directly okay these are + + + align:start position:0% +see your target directly okay these are +cases where you don't need a broader + + align:start position:0% +cases where you don't need a broader + + + align:start position:0% +cases where you don't need a broader +long-term knowledge of the whole + + align:start position:0% +long-term knowledge of the whole + + + align:start position:0% +long-term knowledge of the whole +environment if you can see your target + + align:start position:0% +environment if you can see your target + + + align:start position:0% +environment if you can see your target +you just go straight for it okay so + + align:start position:0% +you just go straight for it okay so + + + align:start position:0% +you just go straight for it okay so +that's beaconing + + align:start position:0% +that's beaconing + + + align:start position:0% +that's beaconing +simplest kind of a to b + + align:start position:0% +simplest kind of a to b + + + align:start position:0% +simplest kind of a to b +um and it requires no mental map no kind + + align:start position:0% +um and it requires no mental map no kind + + + align:start position:0% +um and it requires no mental map no kind +of internal model of the whole world + + align:start position:0% +of internal model of the whole world + + + align:start position:0% +of internal model of the whole world +you're navigating in + + align:start position:0% +you're navigating in + + + align:start position:0% +you're navigating in +but if you can't see the place you want + + align:start position:0% +but if you can't see the place you want + + + align:start position:0% +but if you can't see the place you want +to go + + align:start position:0% +to go + + + align:start position:0% +to go +then you need some kind of mental map of + + align:start position:0% +then you need some kind of mental map of + + + align:start position:0% +then you need some kind of mental map of +the world so what do we mean by a mental + + align:start position:0% +the world so what do we mean by a mental + + + align:start position:0% +the world so what do we mean by a mental +map of the world + + align:start position:0% +map of the world + + + align:start position:0% +map of the world +well this idea was first articulated in + + align:start position:0% +well this idea was first articulated in + + + align:start position:0% +well this idea was first articulated in +a classic experiment way back in the + + align:start position:0% +a classic experiment way back in the + + + align:start position:0% +a classic experiment way back in the +1940s + + align:start position:0% +1940s + + + align:start position:0% +1940s +so this was actually one of the original + + align:start position:0% +so this was actually one of the original + + + align:start position:0% +so this was actually one of the original +experiments that launched the cognitive + + align:start position:0% +experiments that launched the cognitive + + + align:start position:0% +experiments that launched the cognitive +revolution when we emerged from the the + + align:start position:0% +revolution when we emerged from the the + + + align:start position:0% +revolution when we emerged from the the +scourge of behaviorism uh to realize it + + align:start position:0% +scourge of behaviorism uh to realize it + + + align:start position:0% +scourge of behaviorism uh to realize it +was actually okay and indeed of the + + align:start position:0% +was actually okay and indeed of the + + + align:start position:0% +was actually okay and indeed of the +essence to talk about what's going on in + + align:start position:0% +essence to talk about what's going on in + + + align:start position:0% +essence to talk about what's going on in +the mind + + align:start position:0% +the mind + + + align:start position:0% +the mind +and a really influential study that + + align:start position:0% +and a really influential study that + + + align:start position:0% +and a really influential study that +launched the cognitive revolution + + align:start position:0% +launched the cognitive revolution + + + align:start position:0% +launched the cognitive revolution +by tolman + + align:start position:0% +by tolman + + + align:start position:0% +by tolman +was done on rats and it went like this + + align:start position:0% +was done on rats and it went like this + + + align:start position:0% +was done on rats and it went like this +he trained rats he put them down in this + + align:start position:0% +he trained rats he put them down in this + + + align:start position:0% +he trained rats he put them down in this +area and they had to learn that there + + align:start position:0% +area and they had to learn that there + + + align:start position:0% +area and they had to learn that there +would be full + + align:start position:0% +would be full + + + align:start position:0% +would be full +food out there at the goal and so they + + align:start position:0% +food out there at the goal and so they + + + align:start position:0% +food out there at the goal and so they +just have to make the series of left and + + align:start position:0% +just have to make the series of left and + + + align:start position:0% +just have to make the series of left and +right turns to find the food okay so you + + align:start position:0% +right turns to find the food okay so you + + + align:start position:0% +right turns to find the food okay so you +train them on that for a while until + + align:start position:0% +train them on that for a while until + + + align:start position:0% +train them on that for a while until +they're really good at it + + align:start position:0% +they're really good at it + + + align:start position:0% +they're really good at it +and then you put the rats in this + + align:start position:0% +and then you put the rats in this + + + align:start position:0% +and then you put the rats in this +environment + + align:start position:0% +environment + + + align:start position:0% +environment +okay + + align:start position:0% +okay + + + align:start position:0% +okay +now + + align:start position:0% +now + + + align:start position:0% +now +the environment is similar except + + align:start position:0% +the environment is similar except + + + align:start position:0% +the environment is similar except +there's multiple paths + + align:start position:0% +there's multiple paths + + + align:start position:0% +there's multiple paths +one that seems analogous to the old + + align:start position:0% +one that seems analogous to the old + + + align:start position:0% +one that seems analogous to the old +route + + align:start position:0% +route + + + align:start position:0% +route +so what do the rats do in this situation + + align:start position:0% +so what do the rats do in this situation + + + align:start position:0% +so what do the rats do in this situation +they run down here + + align:start position:0% +they run down here + + + align:start position:0% +they run down here +they run into a wall and they realize + + align:start position:0% +they run into a wall and they realize + + + align:start position:0% +they run into a wall and they realize +okay that's not going to work okay + + align:start position:0% +okay that's not going to work okay + + + align:start position:0% +okay that's not going to work okay +nothing no surprises yet + + align:start position:0% +nothing no surprises yet + + + align:start position:0% +nothing no surprises yet +but then the rats immediately come back + + align:start position:0% +but then the rats immediately come back + + + align:start position:0% +but then the rats immediately come back +out and they go straight out that way + + align:start position:0% + + + + align:start position:0% + +what does that tell you + + align:start position:0% +what does that tell you + + + align:start position:0% +what does that tell you +what do they learn + + align:start position:0% +what do they learn + + + align:start position:0% +what do they learn +did they learn a series of like go + + align:start position:0% +did they learn a series of like go + + + align:start position:0% +did they learn a series of like go +straight and then left and then right + + align:start position:0% +straight and then left and then right + + + align:start position:0% +straight and then left and then right +and then right and then go for a long + + align:start position:0% +and then right and then go for a long + + + align:start position:0% +and then right and then go for a long +ways + + align:start position:0% +ways + + + align:start position:0% +ways +no that wouldn't work over here + + align:start position:0% +no that wouldn't work over here + + + align:start position:0% +no that wouldn't work over here +they learned something much more + + align:start position:0% +they learned something much more + + + align:start position:0% +they learned something much more +interesting even though they were only + + align:start position:0% +interesting even though they were only + + + align:start position:0% +interesting even though they were only +being trained on this task here they + + align:start position:0% +being trained on this task here they + + + align:start position:0% +being trained on this task here they +learned some much more interesting thing + + align:start position:0% +learned some much more interesting thing + + + align:start position:0% +learned some much more interesting thing +about the kind of vector average of all + + align:start position:0% +about the kind of vector average of all + + + align:start position:0% +about the kind of vector average of all +of those turns + + align:start position:0% +of those turns + + + align:start position:0% +of those turns +everybody get this it's really simple + + align:start position:0% +everybody get this it's really simple + + + align:start position:0% +everybody get this it's really simple +but really deep + + align:start position:0% +but really deep + + + align:start position:0% +but really deep +okay so from this tolman and others + + align:start position:0% +okay so from this tolman and others + + + align:start position:0% +okay so from this tolman and others +started talking about cognitive maps + + align:start position:0% +started talking about cognitive maps + + + align:start position:0% +started talking about cognitive maps +whatever it is you have to have learned + + align:start position:0% +whatever it is you have to have learned + + + align:start position:0% +whatever it is you have to have learned +in a situation like this so you can + + align:start position:0% +in a situation like this so you can + + + align:start position:0% +in a situation like this so you can +abstract the general direction + + align:start position:0% +abstract the general direction + + + align:start position:0% +abstract the general direction +okay we don't just learn specific roots + + align:start position:0% +okay we don't just learn specific roots + + + align:start position:0% +okay we don't just learn specific roots +as a series of + + align:start position:0% +as a series of + + + align:start position:0% +as a series of +stimulus and responses okay so there + + align:start position:0% +stimulus and responses okay so there + + + align:start position:0% +stimulus and responses okay so there +must be some kind of map in your head to + + align:start position:0% +must be some kind of map in your head to + + + align:start position:0% +must be some kind of map in your head to +be able to do this + + align:start position:0% +be able to do this + + + align:start position:0% +be able to do this +and rats have that + + align:start position:0% +and rats have that + + + align:start position:0% +and rats have that +and so do you + + align:start position:0% +and so do you + + + align:start position:0% +and so do you +so let's consider this question right + + align:start position:0% +so let's consider this question right + + + align:start position:0% +so let's consider this question right +now where am i where are + + align:start position:0% +now where am i where are + + + align:start position:0% +now where am i where are +you to answer that question to yourself + + align:start position:0% +you to answer that question to yourself + + + align:start position:0% +you to answer that question to yourself +there's something like this in your head + + align:start position:0% +there's something like this in your head + + + align:start position:0% +there's something like this in your head +and it probably doesn't look exactly + + align:start position:0% +and it probably doesn't look exactly + + + align:start position:0% +and it probably doesn't look exactly +like that in your head but there's some + + align:start position:0% +like that in your head but there's some + + + align:start position:0% +like that in your head but there's some +version of this information + + align:start position:0% +version of this information + + + align:start position:0% +version of this information +that's in your head + + align:start position:0% +that's in your head + + + align:start position:0% +that's in your head +that you're using when you answer the + + align:start position:0% +that you're using when you answer the + + + align:start position:0% +that you're using when you answer the +question of where you are + + align:start position:0% +question of where you are + + + align:start position:0% +question of where you are +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so + + align:start position:0% +so + + + align:start position:0% +so +um and you have some way to say in that + + align:start position:0% +um and you have some way to say in that + + + align:start position:0% +um and you have some way to say in that +map of the world i know not just what + + align:start position:0% +map of the world i know not just what + + + align:start position:0% +map of the world i know not just what +the mit campus looks like and how it's + + align:start position:0% +the mit campus looks like and how it's + + + align:start position:0% +the mit campus looks like and how it's +arranged but i know where i am in it + + align:start position:0% +arranged but i know where i am in it + + + align:start position:0% +arranged but i know where i am in it +okay + + align:start position:0% + + + + align:start position:0% + +now if you want to know how to get + + align:start position:0% +now if you want to know how to get + + + align:start position:0% +now if you want to know how to get +somewhere else like suppose you're + + align:start position:0% +somewhere else like suppose you're + + + align:start position:0% +somewhere else like suppose you're +hungry and you want to go over to the + + align:start position:0% +hungry and you want to go over to the + + + align:start position:0% +hungry and you want to go over to the +stata cafeteria over there + + align:start position:0% +stata cafeteria over there + + + align:start position:0% +stata cafeteria over there +what else do you need to know besides + + align:start position:0% +what else do you need to know besides + + + align:start position:0% +what else do you need to know besides +knowledge of the map of your environment + + align:start position:0% +knowledge of the map of your environment + + + align:start position:0% +knowledge of the map of your environment +and where you are in it what else do you + + align:start position:0% +and where you are in it what else do you + + + align:start position:0% +and where you are in it what else do you +need to know + + align:start position:0% + + + + align:start position:0% + +you know + + align:start position:0% +you know + + + align:start position:0% +you know +you have this map you know where you are + + align:start position:0% +you have this map you know where you are + + + align:start position:0% +you have this map you know where you are +and you know where your goal is now you + + align:start position:0% +and you know where your goal is now you + + + align:start position:0% +and you know where your goal is now you +have to plan how to get over there what + + align:start position:0% +have to plan how to get over there what + + + align:start position:0% +have to plan how to get over there what +else do you need to know + + align:start position:0% +else do you need to know + + + align:start position:0% +else do you need to know +yeah you have to know which parts are + + align:start position:0% +yeah you have to know which parts are + + + align:start position:0% +yeah you have to know which parts are +like paths and which parts are buildings + + align:start position:0% +like paths and which parts are buildings + + + align:start position:0% +like paths and which parts are buildings +yes exactly where can you go in there + + align:start position:0% +yes exactly where can you go in there + + + align:start position:0% +yes exactly where can you go in there +actually where can you physically get + + align:start position:0% +actually where can you physically get + + + align:start position:0% +actually where can you physically get +through like actually our vector is + + align:start position:0% +through like actually our vector is + + + align:start position:0% +through like actually our vector is +right over there but you can't go that + + align:start position:0% +right over there but you can't go that + + + align:start position:0% +right over there but you can't go that +way because you can't go through that + + align:start position:0% +way because you can't go through that + + + align:start position:0% +way because you can't go through that +glass even though you can see through it + + align:start position:0% +glass even though you can see through it + + + align:start position:0% +glass even though you can see through it +right so knowledge of physical barriers + + align:start position:0% +right so knowledge of physical barriers + + + align:start position:0% +right so knowledge of physical barriers +and what what's an actual path and what + + align:start position:0% +and what what's an actual path and what + + + align:start position:0% +and what what's an actual path and what +isn't is crucial what else do you need + + align:start position:0% +isn't is crucial what else do you need + + + align:start position:0% +isn't is crucial what else do you need +to know + + align:start position:0% + + + + align:start position:0% + +suppose we had a robot in this room + + align:start position:0% +suppose we had a robot in this room + + + align:start position:0% +suppose we had a robot in this room +sitting + + align:start position:0% +sitting + + + align:start position:0% +sitting +right here facing the front of room like + + align:start position:0% +right here facing the front of room like + + + align:start position:0% +right here facing the front of room like +you guys and we're programming the robot + + align:start position:0% +you guys and we're programming the robot + + + align:start position:0% +you guys and we're programming the robot +on how to get over there what are other + + align:start position:0% +on how to get over there what are other + + + align:start position:0% +on how to get over there what are other +things we'd have to tell that robot to + + align:start position:0% +things we'd have to tell that robot to + + + align:start position:0% +things we'd have to tell that robot to +get it to plan + + align:start position:0% +get it to plan + + + align:start position:0% +get it to plan +how to get over to the stata cafeteria + + align:start position:0% + + + + align:start position:0% + +yeah things to watch out for like cars + + align:start position:0% +yeah things to watch out for like cars + + + align:start position:0% +yeah things to watch out for like cars +and traffic absolutely we'd have to know + + align:start position:0% +and traffic absolutely we'd have to know + + + align:start position:0% +and traffic absolutely we'd have to know +about obstacles like moving obstacles + + align:start position:0% +about obstacles like moving obstacles + + + align:start position:0% +about obstacles like moving obstacles +not just fixed ones absolutely what else + + align:start position:0% +not just fixed ones absolutely what else + + + align:start position:0% +not just fixed ones absolutely what else +yeah an issue or your addition yes he + + align:start position:0% +yeah an issue or your addition yes he + + + align:start position:0% +yeah an issue or your addition yes he +has to know which way he's headed + + align:start position:0% +has to know which way he's headed + + + align:start position:0% +has to know which way he's headed +right you're going to give this robot + + align:start position:0% +right you're going to give this robot + + + align:start position:0% +right you're going to give this robot +instructions on which way to go it + + align:start position:0% +instructions on which way to go it + + + align:start position:0% +instructions on which way to go it +matters a whole lot if the robot is + + align:start position:0% +matters a whole lot if the robot is + + + align:start position:0% +matters a whole lot if the robot is +starting like this + + align:start position:0% +starting like this + + + align:start position:0% +starting like this +or starting like that the instructions + + align:start position:0% +or starting like that the instructions + + + align:start position:0% +or starting like that the instructions +are different in the two cases and + + align:start position:0% +are different in the two cases and + + + align:start position:0% +are different in the two cases and +likewise for you guys to plan a route + + align:start position:0% +likewise for you guys to plan a route + + + align:start position:0% +likewise for you guys to plan a route +you need to know which way you're + + align:start position:0% +you need to know which way you're + + + align:start position:0% +you need to know which way you're +heading + + align:start position:0% +heading + + + align:start position:0% +heading +okay + + align:start position:0% +okay + + + align:start position:0% +okay +if you guys ever been in in manhattan + + align:start position:0% +if you guys ever been in in manhattan + + + align:start position:0% +if you guys ever been in in manhattan +and you come up from the subway and you + + align:start position:0% +and you come up from the subway and you + + + align:start position:0% +and you come up from the subway and you +see the streets going like this and you + + align:start position:0% +see the streets going like this and you + + + align:start position:0% +see the streets going like this and you +know it's north south and you don't know + + align:start position:0% +know it's north south and you don't know + + + align:start position:0% +know it's north south and you don't know +if you're heading south or north right + + align:start position:0% +if you're heading south or north right + + + align:start position:0% +if you're heading south or north right +really common thing okay you need to + + align:start position:0% +really common thing okay you need to + + + align:start position:0% +really common thing okay you need to +it's not enough to know i'm at the + + align:start position:0% +it's not enough to know i'm at the + + + align:start position:0% +it's not enough to know i'm at the +junction of 5th and 22nd you need to + + align:start position:0% +junction of 5th and 22nd you need to + + + align:start position:0% +junction of 5th and 22nd you need to +know am i facing south or north + + align:start position:0% +know am i facing south or north + + + align:start position:0% +know am i facing south or north +otherwise you can't figure out which way + + align:start position:0% +otherwise you can't figure out which way + + + align:start position:0% +otherwise you can't figure out which way +to go + + align:start position:0% +to go + + + align:start position:0% +to go +that's called heading direction okay + + align:start position:0% +that's called heading direction okay + + + align:start position:0% +that's called heading direction okay +um + + align:start position:0% +um + + + align:start position:0% +um +okay we just did all that okay you need + + align:start position:0% +okay we just did all that okay you need + + + align:start position:0% +okay we just did all that okay you need +to know your current heading + + align:start position:0% +to know your current heading + + + align:start position:0% +to know your current heading +okay you also need to know the direction + + align:start position:0% +okay you also need to know the direction + + + align:start position:0% +okay you also need to know the direction +of your goal in order to plan a route to + + align:start position:0% +of your goal in order to plan a route to + + + align:start position:0% +of your goal in order to plan a route to +it + + align:start position:0% +it + + + align:start position:0% +it +okay so in this kind of taxonomy of all + + align:start position:0% +okay so in this kind of taxonomy of all + + + align:start position:0% +okay so in this kind of taxonomy of all +the things you need to know to navigate + + align:start position:0% +the things you need to know to navigate + + + align:start position:0% +the things you need to know to navigate +uh we've just added that if you're gonna + + align:start position:0% +uh we've just added that if you're gonna + + + align:start position:0% +uh we've just added that if you're gonna +navigate in your known environment you + + align:start position:0% +navigate in your known environment you + + + align:start position:0% +navigate in your known environment you +need to know where not just where you + + align:start position:0% +need to know where not just where you + + + align:start position:0% +need to know where not just where you +are in it + + align:start position:0% +are in it + + + align:start position:0% +are in it +but which way you are facing in that + + align:start position:0% +but which way you are facing in that + + + align:start position:0% +but which way you are facing in that +mental map + + align:start position:0% +mental map + + + align:start position:0% +mental map +okay and we also talked about this + + align:start position:0% +okay and we also talked about this + + + align:start position:0% +okay and we also talked about this +business of what routes are possible + + align:start position:0% +business of what routes are possible + + + align:start position:0% +business of what routes are possible +from here how do we move around + + align:start position:0% +from here how do we move around + + + align:start position:0% +from here how do we move around +obstacles + + align:start position:0% +obstacles + + + align:start position:0% +obstacles +uh where are the doors uh where the + + align:start position:0% +uh where are the doors uh where the + + + align:start position:0% +uh where are the doors uh where the +hazards like cars + + align:start position:0% +hazards like cars + + + align:start position:0% +hazards like cars +etc a final thing you need to know + + align:start position:0% +etc a final thing you need to know + + + align:start position:0% +etc a final thing you need to know +is that even if you have a good system + + align:start position:0% +is that even if you have a good system + + + align:start position:0% +is that even if you have a good system +for all of these other bits it's still + + align:start position:0% +for all of these other bits it's still + + + align:start position:0% +for all of these other bits it's still +possible to get lost in all kinds of + + align:start position:0% +possible to get lost in all kinds of + + + align:start position:0% +possible to get lost in all kinds of +ways you lose track you get confused you + + align:start position:0% +ways you lose track you get confused you + + + align:start position:0% +ways you lose track you get confused you +get lost + + align:start position:0% +get lost + + + align:start position:0% +get lost +so we also need a way to reorient + + align:start position:0% +so we also need a way to reorient + + + align:start position:0% +so we also need a way to reorient +ourselves when we're lost and we'll talk + + align:start position:0% +ourselves when we're lost and we'll talk + + + align:start position:0% +ourselves when we're lost and we'll talk +a lot about that in the next lecture + + align:start position:0% +a lot about that in the next lecture + + + align:start position:0% +a lot about that in the next lecture +okay so this is just common sense we're + + align:start position:0% +okay so this is just common sense we're + + + align:start position:0% +okay so this is just common sense we're +doing a kind of low-tech version of mar + + align:start position:0% +doing a kind of low-tech version of mar + + + align:start position:0% +doing a kind of low-tech version of mar +computational theory for navigation like + + align:start position:0% +computational theory for navigation like + + + align:start position:0% +computational theory for navigation like +what are the things that we would need + + align:start position:0% +what are the things that we would need + + + align:start position:0% +what are the things that we would need +to know or that a robot would need to + + align:start position:0% +to know or that a robot would need to + + + align:start position:0% +to know or that a robot would need to +know to be able to navigate + + align:start position:0% +know to be able to navigate + + + align:start position:0% +know to be able to navigate +okay just thinking about the nature of + + align:start position:0% +okay just thinking about the nature of + + + align:start position:0% +okay just thinking about the nature of +the problem + + align:start position:0% +the problem + + + align:start position:0% +the problem +all right + + align:start position:0% +all right + + + align:start position:0% +all right +so that's what we need uh what's the + + align:start position:0% +so that's what we need uh what's the + + + align:start position:0% +so that's what we need uh what's the +neural basis of all of this + + align:start position:0% +neural basis of all of this + + + align:start position:0% +neural basis of all of this +all right + + align:start position:0% +all right + + + align:start position:0% +all right +so i'm going to start right in with the + + align:start position:0% +so i'm going to start right in with the + + + align:start position:0% +so i'm going to start right in with the +parahippocampal place area not to imply + + align:start position:0% +parahippocampal place area not to imply + + + align:start position:0% +parahippocampal place area not to imply +it is the total neural neural basis of + + align:start position:0% +it is the total neural neural basis of + + + align:start position:0% +it is the total neural neural basis of +this whole thing it's just one little + + align:start position:0% +this whole thing it's just one little + + + align:start position:0% +this whole thing it's just one little +piece of a much bigger puzzle but we'll + + align:start position:0% +piece of a much bigger puzzle but we'll + + + align:start position:0% +piece of a much bigger puzzle but we'll +start in there because it's nice and + + align:start position:0% +start in there because it's nice and + + + align:start position:0% +start in there because it's nice and +concrete okay + + align:start position:0% +concrete okay + + + align:start position:0% +concrete okay +all right so this story starts oh god + + align:start position:0% +all right so this story starts oh god + + + align:start position:0% +all right so this story starts oh god +about 20 years ago uh i think i + + align:start position:0% +about 20 years ago uh i think i + + + align:start position:0% +about 20 years ago uh i think i +mentioned some of this in the first + + align:start position:0% +mentioned some of this in the first + + + align:start position:0% +mentioned some of this in the first +class when i talked about the story of + + align:start position:0% +class when i talked about the story of + + + align:start position:0% +class when i talked about the story of +bob and i talked about russell epstein + + align:start position:0% +bob and i talked about russell epstein + + + align:start position:0% +bob and i talked about russell epstein +who was in my postdoc + + align:start position:0% +who was in my postdoc + + + align:start position:0% +who was in my postdoc +and it was doing nice behavioral + + align:start position:0% +and it was doing nice behavioral + + + align:start position:0% +and it was doing nice behavioral +experiments and thought it was trashy + + align:start position:0% +experiments and thought it was trashy + + + align:start position:0% +experiments and thought it was trashy +and cheap to mess around with brain + + align:start position:0% +and cheap to mess around with brain + + + align:start position:0% +and cheap to mess around with brain +imaging and he was going to have none of + + align:start position:0% +imaging and he was going to have none of + + + align:start position:0% +imaging and he was going to have none of +it until i said russell just do one + + align:start position:0% +it until i said russell just do one + + + align:start position:0% +it until i said russell just do one +experiment scan subject looking at + + align:start position:0% +experiment scan subject looking at + + + align:start position:0% +experiment scan subject looking at +scenes i know it's kind of stupid but + + align:start position:0% +scenes i know it's kind of stupid but + + + align:start position:0% +scenes i know it's kind of stupid but +just do it then you'll have a slide for + + align:start position:0% +just do it then you'll have a slide for + + + align:start position:0% +just do it then you'll have a slide for +your job talk + + align:start position:0% +your job talk + + + align:start position:0% +your job talk +and he scans subjects looking at scenes + + align:start position:0% +and he scans subjects looking at scenes + + + align:start position:0% +and he scans subjects looking at scenes +and looking at objects and here is one + + align:start position:0% +and looking at objects and here is one + + + align:start position:0% +and looking at objects and here is one +of those early subjects probably me i + + align:start position:0% +of those early subjects probably me i + + + align:start position:0% +of those early subjects probably me i +don't remember + + align:start position:0% +don't remember + + + align:start position:0% +don't remember +with a bunch of vertical slices through + + align:start position:0% +with a bunch of vertical slices through + + + align:start position:0% +with a bunch of vertical slices through +the brain near the back of the brain + + align:start position:0% +the brain near the back of the brain + + + align:start position:0% +the brain near the back of the brain +down there moving forward as we go up to + + align:start position:0% +down there moving forward as we go up to + + + align:start position:0% +down there moving forward as we go up to +here everybody oriented + + align:start position:0% +here everybody oriented + + + align:start position:0% +here everybody oriented +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so sorry it's not showing up very well + + align:start position:0% +so sorry it's not showing up very well + + + align:start position:0% +so sorry it's not showing up very well +in this lighting but there's a little + + align:start position:0% +in this lighting but there's a little + + + align:start position:0% +in this lighting but there's a little +bilateral region right in the middle + + align:start position:0% +bilateral region right in the middle + + + align:start position:0% +bilateral region right in the middle +there that shows a stronger response + + align:start position:0% +there that shows a stronger response + + + align:start position:0% +there that shows a stronger response +when people look at pictures of scenes + + align:start position:0% +when people look at pictures of scenes + + + align:start position:0% +when people look at pictures of scenes +than when they look at pictures of + + align:start position:0% +than when they look at pictures of + + + align:start position:0% +than when they look at pictures of +objects + + align:start position:0% +objects + + + align:start position:0% +objects +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so + + align:start position:0% +so + + + align:start position:0% +so +we didn't we hadn't predicted this yeah + + align:start position:0% + + + + align:start position:0% + +yeah yeah pink yeah pink is yeah all the + + align:start position:0% +yeah yeah pink yeah pink is yeah all the + + + align:start position:0% +yeah yeah pink yeah pink is yeah all the +colors are um there's significance maps + + align:start position:0% +colors are um there's significance maps + + + align:start position:0% +colors are um there's significance maps +or p levels right so pink is higher than + + align:start position:0% +or p levels right so pink is higher than + + + align:start position:0% +or p levels right so pink is higher than +blue but you know blue is borderline + + align:start position:0% +blue but you know blue is borderline + + + align:start position:0% +blue but you know blue is borderline +significant + + align:start position:0% +significant + + + align:start position:0% +significant +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so this was kind of dopey we didn't + + align:start position:0% +so this was kind of dopey we didn't + + + align:start position:0% +so this was kind of dopey we didn't +actually predict it for any deep reason + + align:start position:0% +actually predict it for any deep reason + + + align:start position:0% +actually predict it for any deep reason +we hadn't been thinking about theories + + align:start position:0% +we hadn't been thinking about theories + + + align:start position:0% +we hadn't been thinking about theories +of navigation or anything like that it + + align:start position:0% +of navigation or anything like that it + + + align:start position:0% +of navigation or anything like that it +was just one of those dumb experiments + + align:start position:0% +was just one of those dumb experiments + + + align:start position:0% +was just one of those dumb experiments +where we found something and we followed + + align:start position:0% +where we found something and we followed + + + align:start position:0% +where we found something and we followed +the data so we found this and it's like + + align:start position:0% +the data so we found this and it's like + + + align:start position:0% +the data so we found this and it's like +okay let's try some other subjects + + align:start position:0% +okay let's try some other subjects + + + align:start position:0% +okay let's try some other subjects +so here are the first nine subjects we + + align:start position:0% +so here are the first nine subjects we + + + align:start position:0% +so here are the first nine subjects we +scanned every single subject had that + + align:start position:0% +scanned every single subject had that + + + align:start position:0% +scanned every single subject had that +kind of signature response in exactly + + align:start position:0% +kind of signature response in exactly + + + align:start position:0% +kind of signature response in exactly +the same place + + align:start position:0% +the same place + + + align:start position:0% +the same place +okay in a part of the brain called + + align:start position:0% +okay in a part of the brain called + + + align:start position:0% +okay in a part of the brain called +parahippocampal cortex + + align:start position:0% +parahippocampal cortex + + + align:start position:0% +parahippocampal cortex +okay so this is very systematic and + + align:start position:0% +okay so this is very systematic and + + + align:start position:0% +okay so this is very systematic and +there's lots of ways to make progress in + + align:start position:0% +there's lots of ways to make progress in + + + align:start position:0% +there's lots of ways to make progress in +science one way is to have a big theory + + align:start position:0% +science one way is to have a big theory + + + align:start position:0% +science one way is to have a big theory +and use it to motivate + + align:start position:0% +and use it to motivate + + + align:start position:0% +and use it to motivate +brilliant elegantly designed experiments + + align:start position:0% +brilliant elegantly designed experiments + + + align:start position:0% +brilliant elegantly designed experiments +and another is you just see something + + align:start position:0% +and another is you just see something + + + align:start position:0% +and another is you just see something +salient and robust that you didn't + + align:start position:0% +salient and robust that you didn't + + + align:start position:0% +salient and robust that you didn't +predict and you follow your nose and try + + align:start position:0% +predict and you follow your nose and try + + + align:start position:0% +predict and you follow your nose and try +to figure it out so that's what we did + + align:start position:0% +to figure it out so that's what we did + + + align:start position:0% +to figure it out so that's what we did +in this case it's like okay what the + + align:start position:0% +in this case it's like okay what the + + + align:start position:0% +in this case it's like okay what the +hell is that + + align:start position:0% +hell is that + + + align:start position:0% +hell is that +all right + + align:start position:0% +all right + + + align:start position:0% +all right +so um + + align:start position:0% +so um + + + align:start position:0% +so um +if you think about we eventually called + + align:start position:0% +if you think about we eventually called + + + align:start position:0% +if you think about we eventually called +it the para campbell place area after a + + align:start position:0% +it the para campbell place area after a + + + align:start position:0% +it the para campbell place area after a +little more work + + align:start position:0% +little more work + + + align:start position:0% +little more work +if you think about what we have so far + + align:start position:0% +if you think about what we have so far + + + align:start position:0% +if you think about what we have so far +we've scanned people looking at pictures + + align:start position:0% +we've scanned people looking at pictures + + + align:start position:0% +we've scanned people looking at pictures +like this and pictures like that and + + align:start position:0% +like this and pictures like that and + + + align:start position:0% +like this and pictures like that and +what we've shown is that little patch of + + align:start position:0% +what we've shown is that little patch of + + + align:start position:0% +what we've shown is that little patch of +brain responds a bunch more to these + + align:start position:0% +brain responds a bunch more to these + + + align:start position:0% +brain responds a bunch more to these +than those + + align:start position:0% +than those + + + align:start position:0% +than those +so my first question is is that a + + align:start position:0% +so my first question is is that a + + + align:start position:0% +so my first question is is that a +minimal pair + + align:start position:0% + + + + align:start position:0% + +talia's had a minimal pair sorry i'm + + align:start position:0% +talia's had a minimal pair sorry i'm + + + align:start position:0% +talia's had a minimal pair sorry i'm +like + + align:start position:0% +like + + + align:start position:0% +like +boys + + align:start position:0% +boys + + + align:start position:0% +boys +sorry simple simple simple we're + + align:start position:0% +sorry simple simple simple we're + + + align:start position:0% +sorry simple simple simple we're +contrasting this with that + + align:start position:0% +contrasting this with that + + + align:start position:0% +contrasting this with that +um can you remind me what i'm going to + + align:start position:0% +um can you remind me what i'm going to + + + align:start position:0% +um can you remind me what i'm going to +do okay minimal pair is this thing we + + align:start position:0% +do okay minimal pair is this thing we + + + align:start position:0% +do okay minimal pair is this thing we +aspire towards in experimental design + + align:start position:0% +aspire towards in experimental design + + + align:start position:0% +aspire towards in experimental design +where we have two conditions that are + + align:start position:0% +where we have two conditions that are + + + align:start position:0% +where we have two conditions that are +identical except for one little thing + + align:start position:0% +identical except for one little thing + + + align:start position:0% +identical except for one little thing +we're manipulating + + align:start position:0% +we're manipulating + + + align:start position:0% +we're manipulating +i + + align:start position:0% +i + + + align:start position:0% +i +don't i don't really think it's a + + align:start position:0% +don't i don't really think it's a + + + align:start position:0% +don't i don't really think it's a +minimal pair but i'm not really sure + + align:start position:0% +minimal pair but i'm not really sure + + + align:start position:0% +minimal pair but i'm not really sure +like + + align:start position:0% +like + + + align:start position:0% +like +well i even told you what we were + + align:start position:0% +well i even told you what we were + + + align:start position:0% +well i even told you what we were +designing to manipulate but + + align:start position:0% +designing to manipulate but + + + align:start position:0% +designing to manipulate but +there seems to be like too many + + align:start position:0% +there seems to be like too many + + + align:start position:0% +there seems to be like too many +differences between the living room and + + align:start position:0% +differences between the living room and + + + align:start position:0% +differences between the living room and +like + + align:start position:0% +like + + + align:start position:0% +like +it's ludicrous right i mean it's a + + align:start position:0% +it's ludicrous right i mean it's a + + + align:start position:0% +it's ludicrous right i mean it's a +million differences here right so we + + align:start position:0% +million differences here right so we + + + align:start position:0% +million differences here right so we +don't know that we have anything yet + + align:start position:0% +don't know that we have anything yet + + + align:start position:0% +don't know that we have anything yet +there's all kinds of uninteresting + + align:start position:0% +there's all kinds of uninteresting + + + align:start position:0% +there's all kinds of uninteresting +accounts of the systematic activation in + + align:start position:0% +accounts of the systematic activation in + + + align:start position:0% +accounts of the systematic activation in +that part of the brain right so just to + + align:start position:0% +that part of the brain right so just to + + + align:start position:0% +that part of the brain right so just to +list a few that you've probably already + + align:start position:0% +list a few that you've probably already + + + align:start position:0% +list a few that you've probably already +noticed + + align:start position:0% +noticed + + + align:start position:0% +noticed +these things have rich high level + + align:start position:0% +these things have rich high level + + + align:start position:0% +these things have rich high level +meaning and complexity right so you + + align:start position:0% +meaning and complexity right so you + + + align:start position:0% +meaning and complexity right so you +could think about living rooms or where + + align:start position:0% +could think about living rooms or where + + + align:start position:0% +could think about living rooms or where +you might sit or you know somebody's + + align:start position:0% +you might sit or you know somebody's + + + align:start position:0% +you might sit or you know somebody's +aesthetic + + align:start position:0% +aesthetic + + + align:start position:0% +aesthetic +you know home design or you know god + + align:start position:0% +you know home design or you know god + + + align:start position:0% +you know home design or you know god +there's all kinds of stuff to think + + align:start position:0% +there's all kinds of stuff to think + + + align:start position:0% +there's all kinds of stuff to think +about there + + align:start position:0% +about there + + + align:start position:0% +about there +much more than just okay it's a blender + + align:start position:0% +much more than just okay it's a blender + + + align:start position:0% +much more than just okay it's a blender +right so there's just just complexity in + + align:start position:0% +right so there's just just complexity in + + + align:start position:0% +right so there's just just complexity in +every possible way + + align:start position:0% +every possible way + + + align:start position:0% +every possible way +there are also + + align:start position:0% +there are also + + + align:start position:0% +there are also +lots of objects present here + + align:start position:0% +lots of objects present here + + + align:start position:0% +lots of objects present here +and only a single object over there so + + align:start position:0% +and only a single object over there so + + + align:start position:0% +and only a single object over there so +maybe that region it just represents + + align:start position:0% +maybe that region it just represents + + + align:start position:0% +maybe that region it just represents +objects and if you have more objects you + + align:start position:0% +objects and if you have more objects you + + + align:start position:0% +objects and if you have more objects you +get a higher signal right + + align:start position:0% +get a higher signal right + + + align:start position:0% +get a higher signal right +there's another possibility + + align:start position:0% +there's another possibility + + + align:start position:0% +there's another possibility +and that is that these images depict + + align:start position:0% +and that is that these images depict + + + align:start position:0% +and that is that these images depict +spatial layout and that one does not + + align:start position:0% +spatial layout and that one does not + + + align:start position:0% +spatial layout and that one does not +okay so you have some sense of the walls + + align:start position:0% +okay so you have some sense of the walls + + + align:start position:0% +okay so you have some sense of the walls +and the floor and like the layout of the + + align:start position:0% +and the floor and like the layout of the + + + align:start position:0% +and the floor and like the layout of the +local environment here that you don't + + align:start position:0% +local environment here that you don't + + + align:start position:0% +local environment here that you don't +have over there + + align:start position:0% +have over there + + + align:start position:0% +have over there +all right and we could probably list a + + align:start position:0% +all right and we could probably list a + + + align:start position:0% +all right and we could probably list a +million other things okay that's a very + + align:start position:0% +million other things okay that's a very + + + align:start position:0% +million other things okay that's a very +very sloppy contrast + + align:start position:0% +very sloppy contrast + + + align:start position:0% +very sloppy contrast +okay so how are we going to ask which of + + align:start position:0% +okay so how are we going to ask which of + + + align:start position:0% +okay so how are we going to ask which of +these things might be driving the + + align:start position:0% +these things might be driving the + + + align:start position:0% +these things might be driving the +response of that region + + align:start position:0% +response of that region + + + align:start position:0% +response of that region +well + + align:start position:0% +well + + + align:start position:0% +well +a natural thing to do is just + + align:start position:0% +a natural thing to do is just + + + align:start position:0% +a natural thing to do is just +deconstruct the stimuli + + align:start position:0% +deconstruct the stimuli + + + align:start position:0% +deconstruct the stimuli +so here's what we did uh this is + + align:start position:0% +so here's what we did uh this is + + + align:start position:0% +so here's what we did uh this is +actually way back 20 years ago there + + align:start position:0% +actually way back 20 years ago there + + + align:start position:0% +actually way back 20 years ago there +were better methods at the time but i + + align:start position:0% +were better methods at the time but i + + + align:start position:0% +were better methods at the time but i +didn't know them so i actually drove + + align:start position:0% +didn't know them so i actually drove + + + align:start position:0% +didn't know them so i actually drove +around cambridge photographs my friends + + align:start position:0% +around cambridge photographs my friends + + + align:start position:0% +around cambridge photographs my friends +apartments left the camera on the same + + align:start position:0% +apartments left the camera on the same + + + align:start position:0% +apartments left the camera on the same +tripod moved all the furniture out of + + align:start position:0% +tripod moved all the furniture out of + + + align:start position:0% +tripod moved all the furniture out of +the way and photographed the space again + + align:start position:0% +the way and photographed the space again + + + align:start position:0% +the way and photographed the space again +i know + + align:start position:0% + + + + align:start position:0% + +and then these we probably cut out with + + align:start position:0% +and then these we probably cut out with + + + align:start position:0% +and then these we probably cut out with +some + + align:start position:0% +some + + + align:start position:0% +some +horrific version of adobe photoshop that + + align:start position:0% +horrific version of adobe photoshop that + + + align:start position:0% +horrific version of adobe photoshop that +existed 20 years ago + + align:start position:0% +existed 20 years ago + + + align:start position:0% +existed 20 years ago +anyway we deconstructed the scenes into + + align:start position:0% +anyway we deconstructed the scenes into + + + align:start position:0% +anyway we deconstructed the scenes into +their component objects and the bare + + align:start position:0% +their component objects and the bare + + + align:start position:0% +their component objects and the bare +spatial layout + + align:start position:0% +spatial layout + + + align:start position:0% +spatial layout +okay everybody get the logic here just + + align:start position:0% +okay everybody get the logic here just + + + align:start position:0% +okay everybody get the logic here just +to try to make a big cut in this + + align:start position:0% +to try to make a big cut in this + + + align:start position:0% +to try to make a big cut in this +hypothesis space of what might be + + align:start position:0% +hypothesis space of what might be + + + align:start position:0% +hypothesis space of what might be +driving that region + + align:start position:0% +driving that region + + + align:start position:0% +driving that region +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so what do we predict that the ppa will + + align:start position:0% +so what do we predict that the ppa will + + + align:start position:0% +so what do we predict that the ppa will +resp how how strongly will it respond + + align:start position:0% +resp how how strongly will it respond + + + align:start position:0% +resp how how strongly will it respond +um + + align:start position:0% +um + + + align:start position:0% +um +oops + + align:start position:0% +oops + + + align:start position:0% +oops +how strongly will it respond if these + + align:start position:0% +how strongly will it respond if these + + + align:start position:0% +how strongly will it respond if these +two things are true if it's a complexity + + align:start position:0% +two things are true if it's a complexity + + + align:start position:0% +two things are true if it's a complexity +or multiplicity of objects that's + + align:start position:0% +or multiplicity of objects that's + + + align:start position:0% +or multiplicity of objects that's +driving it what do you predict we will + + align:start position:0% +driving it what do you predict we will + + + align:start position:0% +driving it what do you predict we will +see over there we already know you get a + + align:start position:0% +see over there we already know you get a + + + align:start position:0% +see over there we already know you get a +high response here what do we get over + + align:start position:0% +high response here what do we get over + + + align:start position:0% +high response here what do we get over +there + + align:start position:0% + + + + align:start position:0% + +yeah probably + + align:start position:0% +yeah probably + + + align:start position:0% +yeah probably +yeah we'll respond more to this than + + align:start position:0% +yeah we'll respond more to this than + + + align:start position:0% +yeah we'll respond more to this than +that + + align:start position:0% +that + + + align:start position:0% +that +right it's really simple-minded right + + align:start position:0% +right it's really simple-minded right + + + align:start position:0% +right it's really simple-minded right +if ins if instead it responds more to + + align:start position:0% +if ins if instead it responds more to + + + align:start position:0% +if ins if instead it responds more to +the spatial layout + + align:start position:0% +the spatial layout + + + align:start position:0% +the spatial layout +what do we predict + + align:start position:0% + + + + align:start position:0% + +the is + + align:start position:0% +the is + + + align:start position:0% +the is +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +and that seems like a weird hypothesis + + align:start position:0% +and that seems like a weird hypothesis + + + align:start position:0% +and that seems like a weird hypothesis +because these are really boring there's + + align:start position:0% +because these are really boring there's + + + align:start position:0% +because these are really boring there's +kind of nothing going on here and + + align:start position:0% +kind of nothing going on here and + + + align:start position:0% +kind of nothing going on here and +there's just lots of stuff going on here + + align:start position:0% +there's just lots of stuff going on here + + + align:start position:0% +there's just lots of stuff going on here +i mean it's not riveting but it's a + + align:start position:0% +i mean it's not riveting but it's a + + + align:start position:0% +i mean it's not riveting but it's a +whole much + + align:start position:0% +whole much + + + align:start position:0% +whole much +whole lot more interesting to look at + + align:start position:0% +whole lot more interesting to look at + + + align:start position:0% +whole lot more interesting to look at +these than those believe me i got + + align:start position:0% +these than those believe me i got + + + align:start position:0% +these than those believe me i got +scanned for hours and hours looking at + + align:start position:0% +scanned for hours and hours looking at + + + align:start position:0% +scanned for hours and hours looking at +these things and whenever the empty + + align:start position:0% +these things and whenever the empty + + + align:start position:0% +these things and whenever the empty +rooms came on i was like oh my god i'm + + align:start position:0% +rooms came on i was like oh my god i'm + + + align:start position:0% +rooms came on i was like oh my god i'm +just so bored right there's just nothing + + align:start position:0% +just so bored right there's just nothing + + + align:start position:0% +just so bored right there's just nothing +here whereas here at least there's stuff + + align:start position:0% +here whereas here at least there's stuff + + + align:start position:0% +here whereas here at least there's stuff +right + + align:start position:0% +right + + + align:start position:0% +right +but that's not what the ppa thinks + + align:start position:0% +but that's not what the ppa thinks + + + align:start position:0% +but that's not what the ppa thinks +what the pva does oops + + align:start position:0% +what the pva does oops + + + align:start position:0% +what the pva does oops +oops we just did the localizer okay + + align:start position:0% +oops we just did the localizer okay + + + align:start position:0% +oops we just did the localizer okay +it responds like this this is percent + + align:start position:0% +it responds like this this is percent + + + align:start position:0% +it responds like this this is percent +signal change a measure of magnitude of + + align:start position:0% +signal change a measure of magnitude of + + + align:start position:0% +signal change a measure of magnitude of +response to the full scenes + + align:start position:0% +response to the full scenes + + + align:start position:0% +response to the full scenes +way down less than half the response to + + align:start position:0% +way down less than half the response to + + + align:start position:0% +way down less than half the response to +all those objects and almost the same + + align:start position:0% +all those objects and almost the same + + + align:start position:0% +all those objects and almost the same +response as the original scene + + align:start position:0% +response as the original scene + + + align:start position:0% +response as the original scene +when all you have is a bare spatial + + align:start position:0% +when all you have is a bare spatial + + + align:start position:0% +when all you have is a bare spatial +layout + + align:start position:0% + + + + align:start position:0% + +pretty surprising isn't it + + align:start position:0% +pretty surprising isn't it + + + align:start position:0% +pretty surprising isn't it +we were blown away we're like what what + + align:start position:0% + + + + align:start position:0% + +but can you see how even this really + + align:start position:0% +but can you see how even this really + + + align:start position:0% +but can you see how even this really +simple-minded experiment enables us to + + align:start position:0% +simple-minded experiment enables us to + + + align:start position:0% +simple-minded experiment enables us to +just pretty much rule out that whole + + align:start position:0% +just pretty much rule out that whole + + + align:start position:0% +just pretty much rule out that whole +space of hypotheses it's not about the + + align:start position:0% +space of hypotheses it's not about the + + + align:start position:0% +space of hypotheses it's not about the +richness or interest or multiplicity of + + align:start position:0% +richness or interest or multiplicity of + + + align:start position:0% +richness or interest or multiplicity of +objects + + align:start position:0% +objects + + + align:start position:0% +objects +it's something much more like spatial + + align:start position:0% +it's something much more like spatial + + + align:start position:0% +it's something much more like spatial +layout because that's kind of all there + + align:start position:0% +layout because that's kind of all there + + + align:start position:0% +layout because that's kind of all there +is in those empty rooms + + align:start position:0% +is in those empty rooms + + + align:start position:0% +is in those empty rooms +i mean it could be something like you + + align:start position:0% +i mean it could be something like you + + + align:start position:0% +i mean it could be something like you +know the texture of wood floors or + + align:start position:0% +know the texture of wood floors or + + + align:start position:0% +know the texture of wood floors or +something weird like that + + align:start position:0% +something weird like that + + + align:start position:0% +something weird like that +but one's first guess is it's something + + align:start position:0% +but one's first guess is it's something + + + align:start position:0% +but one's first guess is it's something +about spatial layout does this make + + align:start position:0% +about spatial layout does this make + + + align:start position:0% +about spatial layout does this make +sense it's just a way to take a + + align:start position:0% +sense it's just a way to take a + + + align:start position:0% +sense it's just a way to take a +a big sloppy contrast and try to + + align:start position:0% +a big sloppy contrast and try to + + + align:start position:0% +a big sloppy contrast and try to +formulate initial hypotheses and knock + + align:start position:0% +formulate initial hypotheses and knock + + + align:start position:0% +formulate initial hypotheses and knock +out a whole big space of hypotheses yes + + align:start position:0% +out a whole big space of hypotheses yes + + + align:start position:0% +out a whole big space of hypotheses yes +is it alana yeah yeah + + align:start position:0% +is it alana yeah yeah + + + align:start position:0% +is it alana yeah yeah +i'm sorry i might have missed your + + align:start position:0% +i'm sorry i might have missed your + + + align:start position:0% +i'm sorry i might have missed your +original design + + align:start position:0% +original design + + + align:start position:0% +original design +looking at the empty room + + align:start position:0% + + + + align:start position:0% + +ah good question i skipped over all of + + align:start position:0% +ah good question i skipped over all of + + + align:start position:0% +ah good question i skipped over all of +that + + align:start position:0% +that + + + align:start position:0% +that +uh we didn't + + align:start position:0% +uh we didn't + + + align:start position:0% +uh we didn't +we did yes that's true we did mush them + + align:start position:0% +we did yes that's true we did mush them + + + align:start position:0% +we did yes that's true we did mush them +all together and one could worry about + + align:start position:0% +all together and one could worry about + + + align:start position:0% +all together and one could worry about +that + + align:start position:0% +that + + + align:start position:0% +that +that when you see this you remember that + + align:start position:0% +that when you see this you remember that + + + align:start position:0% +that when you see this you remember that +that's a version of this + + align:start position:0% +that's a version of this + + + align:start position:0% +that's a version of this +right + + align:start position:0% +right + + + align:start position:0% +right +absolutely + + align:start position:0% +absolutely + + + align:start position:0% +absolutely +absolutely + + align:start position:0% +absolutely + + + align:start position:0% +absolutely +um + + align:start position:0% +um + + + align:start position:0% +um +and so maybe yes + + align:start position:0% +and so maybe yes + + + align:start position:0% +and so maybe yes +um nonetheless if what you were doing + + align:start position:0% +um nonetheless if what you were doing + + + align:start position:0% +um nonetheless if what you were doing +that's absolutely true but if what you + + align:start position:0% +that's absolutely true but if what you + + + align:start position:0% +that's absolutely true but if what you +were doing here + + align:start position:0% +were doing here + + + align:start position:0% +were doing here +is kind of mentally recalling this + + align:start position:0% +is kind of mentally recalling this + + + align:start position:0% +is kind of mentally recalling this +right then why couldn't you also do that + + align:start position:0% +right then why couldn't you also do that + + + align:start position:0% +right then why couldn't you also do that +here + + align:start position:0% +here + + + align:start position:0% +here +maybe you could + + align:start position:0% +maybe you could + + + align:start position:0% +maybe you could +you might argue that this is more + + align:start position:0% +you might argue that this is more + + + align:start position:0% +you might argue that this is more +evocative of that than this is but it's + + align:start position:0% +evocative of that than this is but it's + + + align:start position:0% +evocative of that than this is but it's +also got lots of relevant information + + align:start position:0% +also got lots of relevant information + + + align:start position:0% +also got lots of relevant information +okay yeah jimmy you + + align:start position:0% +okay yeah jimmy you + + + align:start position:0% +okay yeah jimmy you +guys the furniture do you guys try + + align:start position:0% +guys the furniture do you guys try + + + align:start position:0% +guys the furniture do you guys try +placing them in the same exact position + + align:start position:0% +placing them in the same exact position + + + align:start position:0% +placing them in the same exact position +as the scene and seeing if that we did + + align:start position:0% +as the scene and seeing if that we did + + + align:start position:0% +as the scene and seeing if that we did +both versions for exactly the reasons + + align:start position:0% +both versions for exactly the reasons + + + align:start position:0% +both versions for exactly the reasons +you guys are pointing out uh and it + + align:start position:0% +you guys are pointing out uh and it + + + align:start position:0% +you guys are pointing out uh and it +didn't make a difference + + align:start position:0% +didn't make a difference + + + align:start position:0% +didn't make a difference +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +yeah uh sorry coolly uh maybe did you + + align:start position:0% +yeah uh sorry coolly uh maybe did you + + + align:start position:0% +yeah uh sorry coolly uh maybe did you +turn for if the if they were just like + + align:start position:0% +turn for if the if they were just like + + + align:start position:0% +turn for if the if they were just like +responding to that there's like + + align:start position:0% +responding to that there's like + + + align:start position:0% +responding to that there's like +more + + align:start position:0% +more + + + align:start position:0% +more +stuff + + align:start position:0% +stuff + + + align:start position:0% +stuff +like in the empty room + + align:start position:0% +like in the empty room + + + align:start position:0% +like in the empty room +there's more background but there's did + + align:start position:0% +there's more background but there's did + + + align:start position:0% +there's more background but there's did +more background totally you're + + align:start position:0% +more background totally you're + + + align:start position:0% +more background totally you're +absolutely right this has taken us + + align:start position:0% +absolutely right this has taken us + + + align:start position:0% +absolutely right this has taken us +pretty far but it's still pretty sloppy + + align:start position:0% +pretty far but it's still pretty sloppy + + + align:start position:0% +pretty far but it's still pretty sloppy +this stuff goes all the way out to the + + align:start position:0% +this stuff goes all the way out to the + + + align:start position:0% +this stuff goes all the way out to the +edge of the frame and here there's lots + + align:start position:0% +edge of the frame and here there's lots + + + align:start position:0% +edge of the frame and here there's lots +of empty space is that what you're + + align:start position:0% +of empty space is that what you're + + + align:start position:0% +of empty space is that what you're +getting at + + align:start position:0% +getting at + + + align:start position:0% +getting at +absolutely i took out those slides + + align:start position:0% +absolutely i took out those slides + + + align:start position:0% +absolutely i took out those slides +because i felt i didn't want to spend + + align:start position:0% +because i felt i didn't want to spend + + + align:start position:0% +because i felt i didn't want to spend +the entire lecture doing millions of + + align:start position:0% +the entire lecture doing millions of + + + align:start position:0% +the entire lecture doing millions of +control conditions on the ppa i thought + + align:start position:0% +control conditions on the ppa i thought + + + align:start position:0% +control conditions on the ppa i thought +you'd get bored but actually another + + align:start position:0% +you'd get bored but actually another + + + align:start position:0% +you'd get bored but actually another +version + + align:start position:0% +version + + + align:start position:0% +version +that we did was we then + + align:start position:0% +that we did was we then + + + align:start position:0% +that we did was we then +took all of these conditions and we + + align:start position:0% +took all of these conditions and we + + + align:start position:0% +took all of these conditions and we +chopped them into little bits and + + align:start position:0% +chopped them into little bits and + + + align:start position:0% +chopped them into little bits and +rearranged the bits + + align:start position:0% +rearranged the bits + + + align:start position:0% +rearranged the bits +so that you have much more coverage of + + align:start position:0% +so that you have much more coverage of + + + align:start position:0% +so that you have much more coverage of +stuff when in the chopped up scenes than + + align:start position:0% +stuff when in the chopped up scenes than + + + align:start position:0% +stuff when in the chopped up scenes than +the chopped up + + align:start position:0% +the chopped up + + + align:start position:0% +the chopped up +uh objects + + align:start position:0% +uh objects + + + align:start position:0% +uh objects +and it in the chopped up versions it + + align:start position:0% +and it in the chopped up versions it + + + align:start position:0% +and it in the chopped up versions it +doesn't respond differently at all so + + align:start position:0% +doesn't respond differently at all so + + + align:start position:0% +doesn't respond differently at all so +it's not the amount of total spatial + + align:start position:0% +it's not the amount of total spatial + + + align:start position:0% +it's not the amount of total spatial +coverage it's the actual something more + + align:start position:0% +coverage it's the actual something more + + + align:start position:0% +coverage it's the actual something more +like the depiction of space + + align:start position:0% +like the depiction of space + + + align:start position:0% +like the depiction of space +was there a question over there yeah i + + align:start position:0% +was there a question over there yeah i + + + align:start position:0% +was there a question over there yeah i +was wondering if there would be any + + align:start position:0% +was wondering if there would be any + + + align:start position:0% +was wondering if there would be any +difference between shooting images as 2d + + align:start position:0% +difference between shooting images as 2d + + + align:start position:0% +difference between shooting images as 2d +for the 3d scene and actually being + + align:start position:0% +for the 3d scene and actually being + + + align:start position:0% +for the 3d scene and actually being +there to see the treatment + + align:start position:0% +there to see the treatment + + + align:start position:0% +there to see the treatment +totally totally it's a real challenge + + align:start position:0% +totally totally it's a real challenge + + + align:start position:0% +totally totally it's a real challenge +with navigation navigation is you know + + align:start position:0% +with navigation navigation is you know + + + align:start position:0% +with navigation navigation is you know +very much about being there and moving + + align:start position:0% +very much about being there and moving + + + align:start position:0% +very much about being there and moving +around in the space + + align:start position:0% +around in the space + + + align:start position:0% +around in the space +and this is just a pretty rudimentary + + align:start position:0% +and this is just a pretty rudimentary + + + align:start position:0% +and this is just a pretty rudimentary +thing where you're lying in the scanner + + align:start position:0% +thing where you're lying in the scanner + + + align:start position:0% +thing where you're lying in the scanner +and these images are just flashing + + align:start position:0% +and these images are just flashing + + + align:start position:0% +and these images are just flashing +flashing on and you're doing some simple + + align:start position:0% +flashing on and you're doing some simple + + + align:start position:0% +flashing on and you're doing some simple +tasks like pressing a button when + + align:start position:0% +tasks like pressing a button when + + + align:start position:0% +tasks like pressing a button when +consecutive images are identical it's + + align:start position:0% +consecutive images are identical it's + + + align:start position:0% +consecutive images are identical it's +not like moving around in the real world + + align:start position:0% +not like moving around in the real world + + + align:start position:0% +not like moving around in the real world +you don't think you're actually there + + align:start position:0% +you don't think you're actually there + + + align:start position:0% +you don't think you're actually there +but here's where video games and vr come + + align:start position:0% +but here's where video games and vr come + + + align:start position:0% +but here's where video games and vr come +in + + align:start position:0% +in + + + align:start position:0% +in +because actually you know they produce a + + align:start position:0% +because actually you know they produce a + + + align:start position:0% +because actually you know they produce a +pretty powerful simulation of knowing + + align:start position:0% +pretty powerful simulation of knowing + + + align:start position:0% +pretty powerful simulation of knowing +your environment feeling you're in a + + align:start position:0% +your environment feeling you're in a + + + align:start position:0% +your environment feeling you're in a +place in it and so lots of studies have + + align:start position:0% +place in it and so lots of studies have + + + align:start position:0% +place in it and so lots of studies have +used those methods to + + align:start position:0% +used those methods to + + + align:start position:0% +used those methods to +give something closer to the actual + + align:start position:0% +give something closer to the actual + + + align:start position:0% +give something closer to the actual +experience of navigation + + align:start position:0% +experience of navigation + + + align:start position:0% +experience of navigation +okay + + align:start position:0% +okay + + + align:start position:0% +okay +um + + align:start position:0% +um + + + align:start position:0% +um +so + + align:start position:0% +so + + + align:start position:0% +so +so where are we so far we've said the + + align:start position:0% +so where are we so far we've said the + + + align:start position:0% +so where are we so far we've said the +ppa seems to be involved in recognizing + + align:start position:0% +ppa seems to be involved in recognizing + + + align:start position:0% +ppa seems to be involved in recognizing +a particular scene so it so this just + + align:start position:0% +a particular scene so it so this just + + + align:start position:0% +a particular scene so it so this just +says it responds to scenes and something + + align:start position:0% +says it responds to scenes and something + + + align:start position:0% +says it responds to scenes and something +about spatial layout maybe + + align:start position:0% +about spatial layout maybe + + + align:start position:0% +about spatial layout maybe +does it care + + align:start position:0% +does it care + + + align:start position:0% +does it care +about that particular scene + + align:start position:0% +about that particular scene + + + align:start position:0% +about that particular scene +or something do you have to recognize + + align:start position:0% +or something do you have to recognize + + + align:start position:0% +or something do you have to recognize +that particular scene to be able to use + + align:start position:0% +that particular scene to be able to use + + + align:start position:0% +that particular scene to be able to use +the information + + align:start position:0% +the information + + + align:start position:0% +the information +now our subjects mostly didn't know + + align:start position:0% +now our subjects mostly didn't know + + + align:start position:0% +now our subjects mostly didn't know +those particular scenes but we wanted to + + align:start position:0% +those particular scenes but we wanted to + + + align:start position:0% +those particular scenes but we wanted to +do a tighter contrast asking if + + align:start position:0% +do a tighter contrast asking if + + + align:start position:0% +do a tighter contrast asking if +knowledge of the particular scene + + align:start position:0% +knowledge of the particular scene + + + align:start position:0% +knowledge of the particular scene +matters + + align:start position:0% +matters + + + align:start position:0% +matters +so what we did was we took a bunch of + + align:start position:0% +so what we did was we took a bunch of + + + align:start position:0% +so what we did was we took a bunch of +pictures around the mit campus and we + + align:start position:0% +pictures around the mit campus and we + + + align:start position:0% +pictures around the mit campus and we +took a bunch of pictures around the + + align:start position:0% +took a bunch of pictures around the + + + align:start position:0% +took a bunch of pictures around the +tufts campus and we scanned mit students + + align:start position:0% +tufts campus and we scanned mit students + + + align:start position:0% +tufts campus and we scanned mit students +looking at mit pictures versus tufts + + align:start position:0% +looking at mit pictures versus tufts + + + align:start position:0% +looking at mit pictures versus tufts +pictures + + align:start position:0% +pictures + + + align:start position:0% +pictures +and then what else do we do + + align:start position:0% + + + + align:start position:0% + +yeah why + + align:start position:0% +yeah why + + + align:start position:0% +yeah why +oh just to make sure that uh it's not + + align:start position:0% +oh just to make sure that uh it's not + + + align:start position:0% +oh just to make sure that uh it's not +all about the weird architecture + + align:start position:0% +all about the weird architecture + + + align:start position:0% +all about the weird architecture +exactly exactly so this is called + + align:start position:0% +exactly exactly so this is called + + + align:start position:0% +exactly exactly so this is called +counter yes who's weird architecture i + + align:start position:0% +counter yes who's weird architecture i + + + align:start position:0% +counter yes who's weird architecture i +think ours is weirder um + + align:start position:0% +think ours is weirder um + + + align:start position:0% +think ours is weirder um +so it's not just about the particular + + align:start position:0% +so it's not just about the particular + + + align:start position:0% +so it's not just about the particular +scenes or the particular subjects so + + align:start position:0% +scenes or the particular subjects so + + + align:start position:0% +scenes or the particular subjects so +everybody get how with that + + align:start position:0% +everybody get how with that + + + align:start position:0% +everybody get how with that +counterbalance design you can really + + align:start position:0% +counterbalance design you can really + + + align:start position:0% +counterbalance design you can really +pull out the essence of familiarity + + align:start position:0% +pull out the essence of familiarity + + + align:start position:0% +pull out the essence of familiarity +itself unconfounded from the particular + + align:start position:0% +itself unconfounded from the particular + + + align:start position:0% +itself unconfounded from the particular +images + + align:start position:0% +images + + + align:start position:0% +images +okay so when we did that + + align:start position:0% +okay so when we did that + + + align:start position:0% +okay so when we did that +we found a very similar response + + align:start position:0% +we found a very similar response + + + align:start position:0% +we found a very similar response +magnitude in the ppa for the + + align:start position:0% +magnitude in the ppa for the + + + align:start position:0% +magnitude in the ppa for the +tough students and for the familiar and + + align:start position:0% +tough students and for the familiar and + + + align:start position:0% +tough students and for the familiar and +unfamiliar scenes okay + + align:start position:0% +unfamiliar scenes okay + + + align:start position:0% +unfamiliar scenes okay +really really didn't make much + + align:start position:0% +really really didn't make much + + + align:start position:0% +really really didn't make much +difference + + align:start position:0% +difference + + + align:start position:0% +difference +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +uh taking a step back so we started with + + align:start position:0% +uh taking a step back so we started with + + + align:start position:0% +uh taking a step back so we started with +the wrong question of navigation yeah + + align:start position:0% +the wrong question of navigation yeah + + + align:start position:0% +the wrong question of navigation yeah +and it involving all these different + + align:start position:0% +and it involving all these different + + + align:start position:0% +and it involving all these different +components + + align:start position:0% +components + + + align:start position:0% +components +uh i just want the place where this + + align:start position:0% +uh i just want the place where this + + + align:start position:0% +uh i just want the place where this +we're getting there we're getting there + + align:start position:0% +we're getting there we're getting there + + + align:start position:0% +we're getting there we're getting there +there won't be like a perfect answer + + align:start position:0% +there won't be like a perfect answer + + + align:start position:0% +there won't be like a perfect answer +we're not going to end up with that + + align:start position:0% +we're not going to end up with that + + + align:start position:0% +we're not going to end up with that +slide with the exact brain region of + + align:start position:0% +slide with the exact brain region of + + + align:start position:0% +slide with the exact brain region of +each of those things uh we'll get some + + align:start position:0% +each of those things uh we'll get some + + + align:start position:0% +each of those things uh we'll get some +gisty vague senses of what this is + + align:start position:0% +gisty vague senses of what this is + + + align:start position:0% +gisty vague senses of what this is +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +okay so this tells us it's not about + + align:start position:0% +okay so this tells us it's not about + + + align:start position:0% +okay so this tells us it's not about +it + + align:start position:0% +it + + + align:start position:0% +it +it's whatever you do whatever the ppa is + + align:start position:0% +it's whatever you do whatever the ppa is + + + align:start position:0% +it's whatever you do whatever the ppa is +responding to in a scene it's not + + align:start position:0% +responding to in a scene it's not + + + align:start position:0% +responding to in a scene it's not +something that hinges on knowing that + + align:start position:0% +something that hinges on knowing that + + + align:start position:0% +something that hinges on knowing that +exact scene so it can't be something + + align:start position:0% +exact scene so it can't be something + + + align:start position:0% +exact scene so it can't be something +like okay if i was here and i wanted to + + align:start position:0% +like okay if i was here and i wanted to + + + align:start position:0% +like okay if i was here and i wanted to +get coffee what would my route from this + + align:start position:0% +get coffee what would my route from this + + + align:start position:0% +get coffee what would my route from this +location be given my knowledge of the + + align:start position:0% +location be given my knowledge of the + + + align:start position:0% +location be given my knowledge of the +environment because otherwise we + + align:start position:0% +environment because otherwise we + + + align:start position:0% +environment because otherwise we +wouldn't get this result so whatever it + + align:start position:0% +wouldn't get this result so whatever it + + + align:start position:0% +wouldn't get this result so whatever it +is it's something more immediate and + + align:start position:0% +is it's something more immediate and + + + align:start position:0% +is it's something more immediate and +perceptual to do with just seeing this + + align:start position:0% +perceptual to do with just seeing this + + + align:start position:0% +perceptual to do with just seeing this +place + + align:start position:0% +place + + + align:start position:0% +place +okay + + align:start position:0% +okay + + + align:start position:0% +okay +all right + + align:start position:0% +all right + + + align:start position:0% +all right +all right so where are we + + align:start position:0% +all right so where are we + + + align:start position:0% +all right so where are we +we've said that there's this region that + + align:start position:0% +we've said that there's this region that + + + align:start position:0% +we've said that there's this region that +responds more to scenes and objects + + align:start position:0% +responds more to scenes and objects + + + align:start position:0% +responds more to scenes and objects +that when all the objects are removed + + align:start position:0% +that when all the objects are removed + + + align:start position:0% +that when all the objects are removed +from the scenes the response you know + + align:start position:0% +from the scenes the response you know + + + align:start position:0% +from the scenes the response you know +barely drops okay + + align:start position:0% +barely drops okay + + + align:start position:0% +barely drops okay +and its response is pretty much the same + + align:start position:0% +and its response is pretty much the same + + + align:start position:0% +and its response is pretty much the same +for familiar and unfamiliar scenes + + align:start position:0% +for familiar and unfamiliar scenes + + + align:start position:0% +for familiar and unfamiliar scenes +so all of that suggests that it's + + align:start position:0% +so all of that suggests that it's + + + align:start position:0% +so all of that suggests that it's +involved in something like perceiving + + align:start position:0% +involved in something like perceiving + + + align:start position:0% +involved in something like perceiving +the shape of space around you + + align:start position:0% +the shape of space around you + + + align:start position:0% +the shape of space around you +it doesn't nail it yet but it + + align:start position:0% +it doesn't nail it yet but it + + + align:start position:0% +it doesn't nail it yet but it +kind of pushes you towards that + + align:start position:0% +kind of pushes you towards that + + + align:start position:0% +kind of pushes you towards that +hypothesis yeah was there a question + + align:start position:0% +hypothesis yeah was there a question + + + align:start position:0% +hypothesis yeah was there a question +here a second ago oh no okay + + align:start position:0% +here a second ago oh no okay + + + align:start position:0% +here a second ago oh no okay +experiment no + + align:start position:0% +experiment no + + + align:start position:0% +experiment no +is it activating you look at it back + + align:start position:0% +is it activating you look at it back + + + align:start position:0% +is it activating you look at it back +oh great question uh not very much + + align:start position:0% +oh great question uh not very much + + + align:start position:0% +oh great question uh not very much +okay + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% +um + + + align:start position:0% +um +yeah if you take pictures of places from + + align:start position:0% +yeah if you take pictures of places from + + + align:start position:0% +yeah if you take pictures of places from +above versus this kind of view you get a + + align:start position:0% +above versus this kind of view you get a + + + align:start position:0% +above versus this kind of view you get a +response in this kind of view but not + + align:start position:0% +response in this kind of view but not + + + align:start position:0% +response in this kind of view but not +above + + align:start position:0% +above + + + align:start position:0% +above +yeah + + align:start position:0% + + + + align:start position:0% + +very telling yeah + + align:start position:0% +very telling yeah + + + align:start position:0% +very telling yeah +okay so i'm going to skip we're not + + align:start position:0% +okay so i'm going to skip we're not + + + align:start position:0% +okay so i'm going to skip we're not +going to do like you know the 30 other + + align:start position:0% +going to do like you know the 30 other + + + align:start position:0% +going to do like you know the 30 other +experiments we're going to skip to the + + align:start position:0% +experiments we're going to skip to the + + + align:start position:0% +experiments we're going to skip to the +general picture that here's the ppa and + + align:start position:0% +general picture that here's the ppa and + + + align:start position:0% +general picture that here's the ppa and +four subjects in this very stereotype + + align:start position:0% +four subjects in this very stereotype + + + align:start position:0% +four subjects in this very stereotype +location and here are some of the many + + align:start position:0% +location and here are some of the many + + + align:start position:0% +location and here are some of the many +conditions we've tested it's not just + + align:start position:0% +conditions we've tested it's not just + + + align:start position:0% +conditions we've tested it's not just +you know abstract maps like this they + + align:start position:0% +you know abstract maps like this they + + + align:start position:0% +you know abstract maps like this they +don't produce a strong response oh this + + align:start position:0% +don't produce a strong response oh this + + + align:start position:0% +don't produce a strong response oh this +is an answer to cooley's question way + + align:start position:0% +is an answer to cooley's question way + + + align:start position:0% +is an answer to cooley's question way +back here's the scrambled up scene much + + align:start position:0% +back here's the scrambled up scene much + + + align:start position:0% +back here's the scrambled up scene much +lower response so it's not just coverage + + align:start position:0% +lower response so it's not just coverage + + + align:start position:0% +lower response so it's not just coverage +of visual junk right + + align:start position:0% +of visual junk right + + + align:start position:0% +of visual junk right +and + + align:start position:0% +and + + + align:start position:0% +and +it responds pretty strongly to scenes + + align:start position:0% +it responds pretty strongly to scenes + + + align:start position:0% +it responds pretty strongly to scenes +made out of legos compared to objects + + align:start position:0% +made out of legos compared to objects + + + align:start position:0% +made out of legos compared to objects +made out of legos and various other + + align:start position:0% +made out of legos and various other + + + align:start position:0% +made out of legos and various other +silly things + + align:start position:0% +silly things + + + align:start position:0% +silly things +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so all of that seems to suggest that + + align:start position:0% +so all of that seems to suggest that + + + align:start position:0% +so all of that seems to suggest that +it's processing something like the shape + + align:start position:0% +it's processing something like the shape + + + align:start position:0% +it's processing something like the shape +or geometry of space around you visible + + align:start position:0% +or geometry of space around you visible + + + align:start position:0% +or geometry of space around you visible +space in your immediate environment + + align:start position:0% +space in your immediate environment + + + align:start position:0% +space in your immediate environment +okay + + align:start position:0% +okay + + + align:start position:0% +okay +nonetheless + + align:start position:0% +nonetheless + + + align:start position:0% +nonetheless +there's always push back + + align:start position:0% +there's always push back + + + align:start position:0% +there's always push back +and there's push back on multiple fronts + + align:start position:0% +and there's push back on multiple fronts + + + align:start position:0% +and there's push back on multiple fronts +and there should be that's proper + + align:start position:0% +and there should be that's proper + + + align:start position:0% +and there should be that's proper +science + + align:start position:0% +science + + + align:start position:0% +science +so one of the lines of pushback + + align:start position:0% +so one of the lines of pushback + + + align:start position:0% +so one of the lines of pushback +was this paper by nasser at all + + align:start position:0% +was this paper by nasser at all + + + align:start position:0% +was this paper by nasser at all +that i didn't assign i signed you the + + align:start position:0% +that i didn't assign i signed you the + + + align:start position:0% +that i didn't assign i signed you the +response to it anyway what nostradal did + + align:start position:0% +response to it anyway what nostradal did + + + align:start position:0% +response to it anyway what nostradal did +was scan people looking at + + align:start position:0% +was scan people looking at + + + align:start position:0% +was scan people looking at +rectilinear things like cubes and + + align:start position:0% +rectilinear things like cubes and + + + align:start position:0% +rectilinear things like cubes and +pyramids versus curvilinear roundy + + align:start position:0% +pyramids versus curvilinear roundy + + + align:start position:0% +pyramids versus curvilinear roundy +things like cones and spheres + + align:start position:0% +things like cones and spheres + + + align:start position:0% +things like cones and spheres +and what they showed is that ppa + + align:start position:0% +and what they showed is that ppa + + + align:start position:0% +and what they showed is that ppa +responds more to the rectilinear than + + align:start position:0% +responds more to the rectilinear than + + + align:start position:0% +responds more to the rectilinear than +the curvilinear shapes + + align:start position:0% +the curvilinear shapes + + + align:start position:0% +the curvilinear shapes +okay + + align:start position:0% +okay + + + align:start position:0% +okay +okay that's the first thing + + align:start position:0% +okay that's the first thing + + + align:start position:0% +okay that's the first thing +and so then they argue that + + align:start position:0% +and so then they argue that + + + align:start position:0% +and so then they argue that +in general scenes have more rectilinear + + align:start position:0% +in general scenes have more rectilinear + + + align:start position:0% +in general scenes have more rectilinear +structure than curvilinear structure and + + align:start position:0% +structure than curvilinear structure and + + + align:start position:0% +structure than curvilinear structure and +they did a bunch of math to make that + + align:start position:0% +they did a bunch of math to make that + + + align:start position:0% +they did a bunch of math to make that +case + + align:start position:0% +case + + + align:start position:0% +case +and so + + align:start position:0% +and so + + + align:start position:0% +and so +they they argue + + align:start position:0% +they they argue + + + align:start position:0% +they they argue +that maybe the apparent scene + + align:start position:0% +that maybe the apparent scene + + + align:start position:0% +that maybe the apparent scene +selectivity of the ppa is due to a what + + align:start position:0% +selectivity of the ppa is due to a what + + + align:start position:0% +selectivity of the ppa is due to a what +of scenes with rectilinearity + + align:start position:0% + + + + align:start position:0% + +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +yes exactly a confound this is exactly + + align:start position:0% +yes exactly a confound this is exactly + + + align:start position:0% +yes exactly a confound this is exactly +what a confound is something else that + + align:start position:0% +what a confound is something else that + + + align:start position:0% +what a confound is something else that +co-varies with the manipulation you care + + align:start position:0% +co-varies with the manipulation you care + + + align:start position:0% +co-varies with the manipulation you care +about that gives you an alternative + + align:start position:0% +about that gives you an alternative + + + align:start position:0% +about that gives you an alternative +account namely okay it's not seeing + + align:start position:0% +account namely okay it's not seeing + + + align:start position:0% +account namely okay it's not seeing +selectivity it's just rectilinearity i + + align:start position:0% +selectivity it's just rectilinearity i + + + align:start position:0% +selectivity it's just rectilinearity i +mean that might be interesting to other + + align:start position:0% +mean that might be interesting to other + + + align:start position:0% +mean that might be interesting to other +people but it would make it not very + + align:start position:0% +people but it would make it not very + + + align:start position:0% +people but it would make it not very +relevant to navigation and much less + + align:start position:0% +relevant to navigation and much less + + + align:start position:0% +relevant to navigation and much less +interesting to me at least right okay + + align:start position:0% +interesting to me at least right okay + + + align:start position:0% +interesting to me at least right okay +so that's an important criticism + + align:start position:0% +so that's an important criticism + + + align:start position:0% +so that's an important criticism +and so then the brian at all paper that + + align:start position:0% +and so then the brian at all paper that + + + align:start position:0% +and so then the brian at all paper that +you guys read starts from there and says + + align:start position:0% +you guys read starts from there and says + + + align:start position:0% +you guys read starts from there and says +okay let's take that seriously let's + + align:start position:0% +okay let's take that seriously let's + + + align:start position:0% +okay let's take that seriously let's +find out + + align:start position:0% +find out + + + align:start position:0% +find out +and so + + align:start position:0% +and so + + + align:start position:0% +and so +um + + align:start position:0% +um + + + align:start position:0% +um +you guys should have read all of this + + align:start position:0% +you guys should have read all of this + + + align:start position:0% +you guys should have read all of this +but just to remind you they have a nice + + align:start position:0% +but just to remind you they have a nice + + + align:start position:0% +but just to remind you they have a nice +little two by two design remember we + + align:start position:0% +little two by two design remember we + + + align:start position:0% +little two by two design remember we +talked about two by two designs where + + align:start position:0% +talked about two by two designs where + + + align:start position:0% +talked about two by two designs where +they manipulate whether the image has a + + align:start position:0% +they manipulate whether the image has a + + + align:start position:0% +they manipulate whether the image has a +lot of rectilinear structure or less + + align:start position:0% +lot of rectilinear structure or less + + + align:start position:0% +lot of rectilinear structure or less +rectilinear structure and whether the + + align:start position:0% +rectilinear structure and whether the + + + align:start position:0% +rectilinear structure and whether the +image is a place or a face + + align:start position:0% +image is a place or a face + + + align:start position:0% +image is a place or a face +okay um + + align:start position:0% +okay um + + + align:start position:0% +okay um +and what they find in the ppa is the + + align:start position:0% +and what they find in the ppa is the + + + align:start position:0% +and what they find in the ppa is the +same response to these + + align:start position:0% +same response to these + + + align:start position:0% +same response to these +and it's higher to the scenes than the + + align:start position:0% +and it's higher to the scenes than the + + + align:start position:0% +and it's higher to the scenes than the +faces + + align:start position:0% +faces + + + align:start position:0% +faces +uh and rectilinearity didn't matter + + align:start position:0% +uh and rectilinearity didn't matter + + + align:start position:0% +uh and rectilinearity didn't matter +for the scenes okay so evidently even + + align:start position:0% +for the scenes okay so evidently even + + + align:start position:0% +for the scenes okay so evidently even +though it does matter with these + + align:start position:0% +though it does matter with these + + + align:start position:0% +though it does matter with these +abstract shapes in actual scenes it + + align:start position:0% +abstract shapes in actual scenes it + + + align:start position:0% +abstract shapes in actual scenes it +doesn't seem and faces it doesn't seem + + align:start position:0% +doesn't seem and faces it doesn't seem + + + align:start position:0% +doesn't seem and faces it doesn't seem +to be doing much it's not accounting for + + align:start position:0% +to be doing much it's not accounting for + + + align:start position:0% +to be doing much it's not accounting for +this difference + + align:start position:0% +this difference + + + align:start position:0% +this difference +okay everybody get that + + align:start position:0% +okay everybody get that + + + align:start position:0% +okay everybody get that +um + + align:start position:0% +um + + + align:start position:0% +um +okay let's talk about this graph + + align:start position:0% +okay let's talk about this graph + + + align:start position:0% +okay let's talk about this graph +are there main effects or interactions + + align:start position:0% +are there main effects or interactions + + + align:start position:0% +are there main effects or interactions +here and what are those main effects or + + align:start position:0% +here and what are those main effects or + + + align:start position:0% +here and what are those main effects or +interactions + + align:start position:0% + + + + align:start position:0% + +yes fully there's immediate scenes yeah + + align:start position:0% +yes fully there's immediate scenes yeah + + + align:start position:0% +yes fully there's immediate scenes yeah +of category scene versus face yeah + + align:start position:0% +of category scene versus face yeah + + + align:start position:0% +of category scene versus face yeah +anything else + + align:start position:0% + + + + align:start position:0% + +that was the first thing + + align:start position:0% +that was the first thing + + + align:start position:0% +that was the first thing +in + + align:start position:0% + + + + align:start position:0% + +oh + + align:start position:0% +oh + + + align:start position:0% +oh +wait this here these are scenes and + + align:start position:0% +wait this here these are scenes and + + + align:start position:0% +wait this here these are scenes and +those are phases + + align:start position:0% +those are phases + + + align:start position:0% +those are phases +okay and i'm sorry and this is the code + + align:start position:0% +okay and i'm sorry and this is the code + + + align:start position:0% +okay and i'm sorry and this is the code +here these are rectilinear versus + + align:start position:0% +here these are rectilinear versus + + + align:start position:0% +here these are rectilinear versus +curvilinear + + align:start position:0% + + + + align:start position:0% + +just one main effect or is there an + + align:start position:0% +just one main effect or is there an + + + align:start position:0% +just one main effect or is there an +interaction or another main effect + + align:start position:0% +interaction or another main effect + + + align:start position:0% +interaction or another main effect +no just one main effect okay + + align:start position:0% +no just one main effect okay + + + align:start position:0% +no just one main effect okay +right these guys are higher than those + + align:start position:0% +right these guys are higher than those + + + align:start position:0% +right these guys are higher than those +guys that's it + + align:start position:0% +guys that's it + + + align:start position:0% +guys that's it +okay so that just tells you there's + + align:start position:0% +okay so that just tells you there's + + + align:start position:0% +okay so that just tells you there's +nothing else going on in these data + + align:start position:0% +nothing else going on in these data + + + align:start position:0% +nothing else going on in these data +other than seeing selectivity + + align:start position:0% +other than seeing selectivity + + + align:start position:0% +other than seeing selectivity +okay rectilinearity doesn't interact + + align:start position:0% +okay rectilinearity doesn't interact + + + align:start position:0% +okay rectilinearity doesn't interact +with or modify scene selectivity and it + + align:start position:0% +with or modify scene selectivity and it + + + align:start position:0% +with or modify scene selectivity and it +doesn't have a separate effect + + align:start position:0% +doesn't have a separate effect + + + align:start position:0% +doesn't have a separate effect +okay + + align:start position:0% +okay + + + align:start position:0% +okay +nonetheless + + align:start position:0% +nonetheless + + + align:start position:0% +nonetheless +as we've been arguing with all the whole + + align:start position:0% +as we've been arguing with all the whole + + + align:start position:0% +as we've been arguing with all the whole +hacks be rigmarole does the fact that + + align:start position:0% +hacks be rigmarole does the fact that + + + align:start position:0% +hacks be rigmarole does the fact that +there's no + + align:start position:0% +there's no + + + align:start position:0% +there's no +main effect of rectilinearity in here + + align:start position:0% +main effect of rectilinearity in here + + + align:start position:0% +main effect of rectilinearity in here +mean that the ppa doesn't have + + align:start position:0% +mean that the ppa doesn't have + + + align:start position:0% +mean that the ppa doesn't have +information about rectilinearity + + align:start position:0% + + + + align:start position:0% + +no josh why + + align:start position:0% +no josh why + + + align:start position:0% +no josh why +i mean there's still a tiny amount that + + align:start position:0% +i mean there's still a tiny amount that + + + align:start position:0% +i mean there's still a tiny amount that +could that could be enough + + align:start position:0% +could that could be enough + + + align:start position:0% +could that could be enough +this is not the right experiment that's + + align:start position:0% +this is not the right experiment that's + + + align:start position:0% +this is not the right experiment that's +right this is a big well it's a right + + align:start position:0% +right this is a big well it's a right + + + align:start position:0% +right this is a big well it's a right +experiment but not the right analysis + + align:start position:0% +experiment but not the right analysis + + + align:start position:0% +experiment but not the right analysis +right it's the big average responses are + + align:start position:0% +right it's the big average responses are + + + align:start position:0% +right it's the big average responses are +the same but maybe the patterns are + + align:start position:0% +the same but maybe the patterns are + + + align:start position:0% +the same but maybe the patterns are +different okay that wouldn't directly + + align:start position:0% +different okay that wouldn't directly + + + align:start position:0% +different okay that wouldn't directly +engage with us but we want to know is + + align:start position:0% +engage with us but we want to know is + + + align:start position:0% +engage with us but we want to know is +there information in there about + + align:start position:0% +there information in there about + + + align:start position:0% +there information in there about +rectilinearity + + align:start position:0% +rectilinearity + + + align:start position:0% +rectilinearity +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so how would we find out + + align:start position:0% +so how would we find out + + + align:start position:0% +so how would we find out +so this was your assignment and i think + + align:start position:0% +so this was your assignment and i think + + + align:start position:0% +so this was your assignment and i think +most people got it right but in case + + align:start position:0% +most people got it right but in case + + + align:start position:0% +most people got it right but in case +anybody missed it + + align:start position:0% +anybody missed it + + + align:start position:0% +anybody missed it +we were zooming in on these this figure + + align:start position:0% +we were zooming in on these this figure + + + align:start position:0% +we were zooming in on these this figure +four here so again this is just the same + + align:start position:0% +four here so again this is just the same + + + align:start position:0% +four here so again this is just the same +basic design of experiment two + + align:start position:0% +basic design of experiment two + + + align:start position:0% +basic design of experiment two +and now let's consider what's going on + + align:start position:0% +and now let's consider what's going on + + + align:start position:0% +and now let's consider what's going on +here so you guys read the paper and you + + align:start position:0% +here so you guys read the paper and you + + + align:start position:0% +here so you guys read the paper and you +understood what was going on here what's + + align:start position:0% +understood what was going on here what's + + + align:start position:0% +understood what was going on here what's +represented in that cell right there + + align:start position:0% +represented in that cell right there + + + align:start position:0% +represented in that cell right there +what is the point of this diagram what + + align:start position:0% +what is the point of this diagram what + + + align:start position:0% +what is the point of this diagram what +are they doing here and what does that + + align:start position:0% +are they doing here and what does that + + + align:start position:0% +are they doing here and what does that +cell mean in that matrix + + align:start position:0% + + + + align:start position:0% + +you can't understand the paper without + + align:start position:0% +you can't understand the paper without + + + align:start position:0% +you can't understand the paper without +knowing that + + align:start position:0% +knowing that + + + align:start position:0% +knowing that +is it ali + + align:start position:0% +is it ali + + + align:start position:0% +is it ali +no sorry + + align:start position:0% +no sorry + + + align:start position:0% +no sorry +what's your name + + align:start position:0% +what's your name + + + align:start position:0% +what's your name +sharon i've only asked you like six + + align:start position:0% +sharon i've only asked you like six + + + align:start position:0% +sharon i've only asked you like six +times yeah go ahead + + align:start position:0% +times yeah go ahead + + + align:start position:0% +times yeah go ahead +so + + align:start position:0% +so + + + align:start position:0% +so +they want to see whether + + align:start position:0% +they want to see whether + + + align:start position:0% +they want to see whether +the + + align:start position:0% +the + + + align:start position:0% +the +activation patterns can better + + align:start position:0% +activation patterns can better + + + align:start position:0% +activation patterns can better +discriminate between + + align:start position:0% +discriminate between + + + align:start position:0% +discriminate between +rectilinearity of the same category of + + align:start position:0% +rectilinearity of the same category of + + + align:start position:0% +rectilinearity of the same category of +things or between categories of things + + align:start position:0% +things or between categories of things + + + align:start position:0% +things or between categories of things +with the same rectilinearity so they um + + align:start position:0% +with the same rectilinearity so they um + + + align:start position:0% +with the same rectilinearity so they um +the first thing i said is + + align:start position:0% +the first thing i said is + + + align:start position:0% +the first thing i said is +to the + + align:start position:0% +to the + + + align:start position:0% +to the +uh + + align:start position:0% +uh + + + align:start position:0% +uh +left and the second one is the right + + align:start position:0% +left and the second one is the right + + + align:start position:0% +left and the second one is the right +and they + + align:start position:0% +and they + + + align:start position:0% +and they +sorry wait here and here no the right + + align:start position:0% +sorry wait here and here no the right + + + align:start position:0% +sorry wait here and here no the right +side yeah so this part that part is + + align:start position:0% +side yeah so this part that part is + + + align:start position:0% +side yeah so this part that part is +discriminating between um + + align:start position:0% +discriminating between um + + + align:start position:0% +discriminating between um +vertical linearity and that side is + + align:start position:0% +vertical linearity and that side is + + + align:start position:0% +vertical linearity and that side is +distributing between categories + + align:start position:0% +distributing between categories + + + align:start position:0% +distributing between categories +and they take the differences of + + align:start position:0% +and they take the differences of + + + align:start position:0% +and they take the differences of +well not the difference if they take + + align:start position:0% +well not the difference if they take + + + align:start position:0% +well not the difference if they take +the + + align:start position:0% +the + + + align:start position:0% +the +how well it can distinguish between each + + align:start position:0% +how well it can distinguish between each + + + align:start position:0% +how well it can distinguish between each +of those categories and plug them down + + align:start position:0% +of those categories and plug them down + + + align:start position:0% +of those categories and plug them down +there + + align:start position:0% +there + + + align:start position:0% +there +right okay + + align:start position:0% +right okay + + + align:start position:0% +right okay +that's exactly right so this is how well + + align:start position:0% +that's exactly right so this is how well + + + align:start position:0% +that's exactly right so this is how well +it can discriminate plotted down here + + align:start position:0% +it can discriminate plotted down here + + + align:start position:0% +it can discriminate plotted down here +but based on an analysis that follows + + align:start position:0% +but based on an analysis that follows + + + align:start position:0% +but based on an analysis that follows +this scheme + + align:start position:0% +this scheme + + + align:start position:0% +this scheme +so what does that cell in there + + align:start position:0% +so what does that cell in there + + + align:start position:0% +so what does that cell in there +represent + + align:start position:0% +represent + + + align:start position:0% +represent +that dark green cell what do they + + align:start position:0% +that dark green cell what do they + + + align:start position:0% +that dark green cell what do they +what is the number that's going to be + + align:start position:0% +what is the number that's going to be + + + align:start position:0% +what is the number that's going to be +calculated from the data corresponding + + align:start position:0% +calculated from the data corresponding + + + align:start position:0% +calculated from the data corresponding +to that cell + + align:start position:0% + + + + align:start position:0% + +similarities of uh saying that + + align:start position:0% +similarities of uh saying that + + + align:start position:0% +similarities of uh saying that +continuity + + align:start position:0% +continuity + + + align:start position:0% +continuity +exactly exactly so just as if you want + + align:start position:0% +exactly exactly so just as if you want + + + align:start position:0% +exactly exactly so just as if you want +to distinguish chairs from cars or + + align:start position:0% +to distinguish chairs from cars or + + + align:start position:0% +to distinguish chairs from cars or +something else if you want to know is + + align:start position:0% +something else if you want to know is + + + align:start position:0% +something else if you want to know is +there information about rectilinearity + + align:start position:0% +there information about rectilinearity + + + align:start position:0% +there information about rectilinearity +in there + + align:start position:0% +in there + + + align:start position:0% +in there +you take these two cases which are the + + align:start position:0% +you take these two cases which are the + + + align:start position:0% +you take these two cases which are the +same in rectilinearity both high + + align:start position:0% +same in rectilinearity both high + + + align:start position:0% +same in rectilinearity both high +rectilinear both low rectilinear + + align:start position:0% +rectilinear both low rectilinear + + + align:start position:0% +rectilinear both low rectilinear +for run one and run two and that's the + + align:start position:0% +for run one and run two and that's the + + + align:start position:0% +for run one and run two and that's the +correlation between run and one 2 for + + align:start position:0% +correlation between run and one 2 for + + + align:start position:0% +correlation between run and one 2 for +those cells + + align:start position:0% +those cells + + + align:start position:0% +those cells +that's the within rectilinearity case + + align:start position:0% +that's the within rectilinearity case + + + align:start position:0% +that's the within rectilinearity case +right and if there's information about + + align:start position:0% +right and if there's information about + + + align:start position:0% +right and if there's information about +rectilinearity the prediction is those + + align:start position:0% +rectilinearity the prediction is those + + + align:start position:0% +rectilinearity the prediction is those +within correlations are higher than the + + align:start position:0% +within correlations are higher than the + + + align:start position:0% +within correlations are higher than the +between correlations + + align:start position:0% +between correlations + + + align:start position:0% +between correlations +just as we argued a bit back with you + + align:start position:0% +just as we argued a bit back with you + + + align:start position:0% +just as we argued a bit back with you +know beaches and cities and everything + + align:start position:0% +know beaches and cities and everything + + + align:start position:0% +know beaches and cities and everything +else okay same argument this is just + + align:start position:0% +else okay same argument this is just + + + align:start position:0% +else okay same argument this is just +presenting the data in terms of run one + + align:start position:0% +presenting the data in terms of run one + + + align:start position:0% +presenting the data in terms of run one +and run two and which cells do we grab + + align:start position:0% +and run two and which cells do we grab + + + align:start position:0% +and run two and which cells do we grab +to do this computation + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so + + align:start position:0% +so + + + align:start position:0% +so +um so each of the cells in there for + + align:start position:0% +um so each of the cells in there for + + + align:start position:0% +um so each of the cells in there for +each of the cells we're going to + + align:start position:0% +each of the cells we're going to + + + align:start position:0% +each of the cells we're going to +calculate an r value of how similar + + align:start position:0% +calculate an r value of how similar + + + align:start position:0% +calculate an r value of how similar +those patterns are + + align:start position:0% +those patterns are + + + align:start position:0% +those patterns are +okay + + align:start position:0% +okay + + + align:start position:0% +okay +pattern and + + align:start position:0% +pattern and + + + align:start position:0% +pattern and +you know a pattern for rectilinear + + align:start position:0% +you know a pattern for rectilinear + + + align:start position:0% +you know a pattern for rectilinear +scenes in run and run two a pattern for + + align:start position:0% +scenes in run and run two a pattern for + + + align:start position:0% +scenes in run and run two a pattern for +rectilinear scenes in run one this cell + + align:start position:0% +rectilinear scenes in run one this cell + + + align:start position:0% +rectilinear scenes in run one this cell +is the correlation between those two + + align:start position:0% +is the correlation between those two + + + align:start position:0% +is the correlation between those two +patterns how stable is that pattern + + align:start position:0% +patterns how stable is that pattern + + + align:start position:0% +patterns how stable is that pattern +across repeated measures + + align:start position:0% +across repeated measures + + + align:start position:0% +across repeated measures +okay + + align:start position:0% +okay + + + align:start position:0% +okay +all right so that's what that r value is + + align:start position:0% +all right so that's what that r value is + + + align:start position:0% +all right so that's what that r value is +the two darker blue scare + + align:start position:0% +the two darker blue scare + + + align:start position:0% +the two darker blue scare +squares here + + align:start position:0% +squares here + + + align:start position:0% +squares here +are the r values + + align:start position:0% +are the r values + + + align:start position:0% +are the r values +for stimuli that differ in + + align:start position:0% +for stimuli that differ in + + + align:start position:0% +for stimuli that differ in +rectilinearity + + align:start position:0% +rectilinearity + + + align:start position:0% +rectilinearity +and remember that the essence of the hex + + align:start position:0% +and remember that the essence of the hex + + + align:start position:0% +and remember that the essence of the hex +b style pattern analysis + + align:start position:0% +b style pattern analysis + + + align:start position:0% +b style pattern analysis +is to + + align:start position:0% +is to + + + align:start position:0% +is to +see if the within correlations are + + align:start position:0% +see if the within correlations are + + + align:start position:0% +see if the within correlations are +higher than the between correlations + + align:start position:0% +higher than the between correlations + + + align:start position:0% +higher than the between correlations +in this case the within correlations are + + align:start position:0% +in this case the within correlations are + + + align:start position:0% +in this case the within correlations are +within rectilinearity versus between + + align:start position:0% +within rectilinearity versus between + + + align:start position:0% +within rectilinearity versus between +rectilinearity + + align:start position:0% +rectilinearity + + + align:start position:0% +rectilinearity +okay + + align:start position:0% + + + + align:start position:0% + +all right + + align:start position:0% +all right + + + align:start position:0% +all right +and so then they calculate all those + + align:start position:0% +and so then they calculate all those + + + align:start position:0% +and so then they calculate all those +correlation differences and they plot + + align:start position:0% +correlation differences and they plot + + + align:start position:0% +correlation differences and they plot +them as discriminate discrimination + + align:start position:0% +them as discriminate discrimination + + + align:start position:0% +them as discriminate discrimination +abilities + + align:start position:0% +abilities + + + align:start position:0% +abilities +and so + + align:start position:0% +and so + + + align:start position:0% +and so +what this is showing us here is that + + align:start position:0% +what this is showing us here is that + + + align:start position:0% +what this is showing us here is that +actually the ppa doesn't have any + + align:start position:0% +actually the ppa doesn't have any + + + align:start position:0% +actually the ppa doesn't have any +information in its pattern of response + + align:start position:0% +information in its pattern of response + + + align:start position:0% +information in its pattern of response +about the rectilinearity of the scene + + align:start position:0% +about the rectilinearity of the scene + + + align:start position:0% +about the rectilinearity of the scene +however if we take the same data + + align:start position:0% +however if we take the same data + + + align:start position:0% +however if we take the same data +and now choose within category versus + + align:start position:0% +and now choose within category versus + + + align:start position:0% +and now choose within category versus +between category + + align:start position:0% +between category + + + align:start position:0% +between category +ignoring rectilinearity and we get the + + align:start position:0% +ignoring rectilinearity and we get the + + + align:start position:0% +ignoring rectilinearity and we get the +same kind of um + + align:start position:0% +same kind of um + + + align:start position:0% +same kind of um +selectivity + + align:start position:0% +selectivity + + + align:start position:0% +selectivity +correlation difference within versus + + align:start position:0% +correlation difference within versus + + + align:start position:0% +correlation difference within versus +between for category there's heaps of + + align:start position:0% +between for category there's heaps of + + + align:start position:0% +between for category there's heaps of +information about category + + align:start position:0% +information about category + + + align:start position:0% +information about category +does that make sense + + align:start position:0% +does that make sense + + + align:start position:0% +does that make sense +okay again if you're fuzzy about this + + align:start position:0% +okay again if you're fuzzy about this + + + align:start position:0% +okay again if you're fuzzy about this +look back on that slide i have lots of + + align:start position:0% +look back on that slide i have lots of + + + align:start position:0% +look back on that slide i have lots of +suggestions for how to unfuzzy yourself + + align:start position:0% +suggestions for how to unfuzzy yourself + + + align:start position:0% +suggestions for how to unfuzzy yourself +on it okay + + align:start position:0% +on it okay + + + align:start position:0% +on it okay +all right so + + align:start position:0% +all right so + + + align:start position:0% +all right so +into room summary pba responds more to + + align:start position:0% +into room summary pba responds more to + + + align:start position:0% +into room summary pba responds more to +scenes and objects + + align:start position:0% +scenes and objects + + + align:start position:0% +scenes and objects +it seems to like spatial layout in + + align:start position:0% +it seems to like spatial layout in + + + align:start position:0% +it seems to like spatial layout in +particular it does respond more to boxes + + align:start position:0% +particular it does respond more to boxes + + + align:start position:0% +particular it does respond more to boxes +and circles but that rectilinearity bias + + align:start position:0% +and circles but that rectilinearity bias + + + align:start position:0% +and circles but that rectilinearity bias +can't account for scene selectivity + + align:start position:0% +can't account for scene selectivity + + + align:start position:0% +can't account for scene selectivity +that's all very nice + + align:start position:0% +that's all very nice + + + align:start position:0% +that's all very nice +but what is a whole other kind of + + align:start position:0% +but what is a whole other kind of + + + align:start position:0% +but what is a whole other kind of +fundamental question we haven't yet + + align:start position:0% +fundamental question we haven't yet + + + align:start position:0% +fundamental question we haven't yet +asked about the ppa + + align:start position:0% + + + + align:start position:0% + +so we've been messing around with + + align:start position:0% +so we've been messing around with + + + align:start position:0% +so we've been messing around with +functional mri measuring magnitudes of + + align:start position:0% +functional mri measuring magnitudes of + + + align:start position:0% +functional mri measuring magnitudes of +response trying to test these kind of + + align:start position:0% +response trying to test these kind of + + + align:start position:0% +response trying to test these kind of +vague + + align:start position:0% +vague + + + align:start position:0% +vague +uh + + align:start position:0% +uh + + + align:start position:0% +uh +you know general hypotheses about what + + align:start position:0% +you know general hypotheses about what + + + align:start position:0% +you know general hypotheses about what +it might be responding to yes + + align:start position:0% +it might be responding to yes + + + align:start position:0% +it might be responding to yes +yes what what particular causation + + align:start position:0% + + + + align:start position:0% + +i guess like how it's in scenes + + align:start position:0% +i guess like how it's in scenes + + + align:start position:0% +i guess like how it's in scenes +like how + + align:start position:0% +like how + + + align:start position:0% +like how +the pva liquid will work place in person + + align:start position:0% +the pva liquid will work place in person + + + align:start position:0% +the pva liquid will work place in person +exactly exactly again we can test the + + align:start position:0% +exactly exactly again we can test the + + + align:start position:0% +exactly exactly again we can test the +causal role of a stimulus on the ppa all + + align:start position:0% +causal role of a stimulus on the ppa all + + + align:start position:0% +causal role of a stimulus on the ppa all +of the stuff i talked about did that + + align:start position:0% +of the stuff i talked about did that + + + align:start position:0% +of the stuff i talked about did that +manipulate the stimulus find different + + align:start position:0% +manipulate the stimulus find different + + + align:start position:0% +manipulate the stimulus find different +ppa responses but what we haven't done + + align:start position:0% +ppa responses but what we haven't done + + + align:start position:0% +ppa responses but what we haven't done +yet is ask + + align:start position:0% +yet is ask + + + align:start position:0% +yet is ask +what is a relation the causal + + align:start position:0% +what is a relation the causal + + + align:start position:0% +what is a relation the causal +relationship if any between activity in + + align:start position:0% +relationship if any between activity in + + + align:start position:0% +relationship if any between activity in +the ppa and perception of scenes or + + align:start position:0% +the ppa and perception of scenes or + + + align:start position:0% +the ppa and perception of scenes or +navigation okay + + align:start position:0% +navigation okay + + + align:start position:0% +navigation okay +so so far this is all just suggestive we + + align:start position:0% +so so far this is all just suggestive we + + + align:start position:0% +so so far this is all just suggestive we +have no causal evidence for its role in + + align:start position:0% +have no causal evidence for its role in + + + align:start position:0% +have no causal evidence for its role in +navigation + + align:start position:0% +navigation + + + align:start position:0% +navigation +right or perception + + align:start position:0% +right or perception + + + align:start position:0% +right or perception +all right so let's get some + + align:start position:0% +all right so let's get some + + + align:start position:0% +all right so let's get some +i'll show you a few examples + + align:start position:0% +i'll show you a few examples + + + align:start position:0% +i'll show you a few examples +um so one as you guys have learned by + + align:start position:0% +um so one as you guys have learned by + + + align:start position:0% +um so one as you guys have learned by +now is these rare cases where there's + + align:start position:0% +now is these rare cases where there's + + + align:start position:0% +now is these rare cases where there's +direct electrical stimulation of a + + align:start position:0% +direct electrical stimulation of a + + + align:start position:0% +direct electrical stimulation of a +region and there's one patient in whom + + align:start position:0% +region and there's one patient in whom + + + align:start position:0% +region and there's one patient in whom +this is reported this patient again is + + align:start position:0% +this is reported this patient again is + + + align:start position:0% +this is reported this patient again is +being mapped out before neurosurgery + + align:start position:0% +being mapped out before neurosurgery + + + align:start position:0% +being mapped out before neurosurgery +there's + + align:start position:0% +there's + + + align:start position:0% +there's +they did functional mri in the patient + + align:start position:0% +they did functional mri in the patient + + + align:start position:0% +they did functional mri in the patient +first this is his functional mri + + align:start position:0% +first this is his functional mri + + + align:start position:0% +first this is his functional mri +response to i think houses versus + + align:start position:0% +response to i think houses versus + + + align:start position:0% +response to i think houses versus +objects houses are not as strong + + align:start position:0% +objects houses are not as strong + + + align:start position:0% +objects houses are not as strong +an activator as scenes for the ppa but + + align:start position:0% +an activator as scenes for the ppa but + + + align:start position:0% +an activator as scenes for the ppa but +they're pretty good ppa responds much + + align:start position:0% +they're pretty good ppa responds much + + + align:start position:0% +they're pretty good ppa responds much +more to houses than other objects and so + + align:start position:0% +more to houses than other objects and so + + + align:start position:0% +more to houses than other objects and so +that's a nice activation map showing the + + align:start position:0% +that's a nice activation map showing the + + + align:start position:0% +that's a nice activation map showing the +ppa and those little circles are where + + align:start position:0% +ppa and those little circles are where + + + align:start position:0% +ppa and those little circles are where +the electrodes are little black circles + + align:start position:0% +the electrodes are little black circles + + + align:start position:0% +the electrodes are little black circles +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so um so they know they're in the ppa + + align:start position:0% +so um so they know they're in the ppa + + + align:start position:0% +so um so they know they're in the ppa +because they did functional mri first to + + align:start position:0% +because they did functional mri first to + + + align:start position:0% +because they did functional mri first to +localize that region now those + + align:start position:0% +localize that region now those + + + align:start position:0% +localize that region now those +electrodes are sitting there + + align:start position:0% +electrodes are sitting there + + + align:start position:0% +electrodes are sitting there +and so first thing we do is record or + + align:start position:0% +and so first thing we do is record or + + + align:start position:0% +and so first thing we do is record or +the first thing they did is record + + align:start position:0% +the first thing they did is record + + + align:start position:0% +the first thing they did is record +responses they flash up a bunch of + + align:start position:0% +responses they flash up a bunch of + + + align:start position:0% +responses they flash up a bunch of +different kind of images and they + + align:start position:0% +different kind of images and they + + + align:start position:0% +different kind of images and they +measure the response in those electrodes + + align:start position:0% +measure the response in those electrodes + + + align:start position:0% +measure the response in those electrodes +and so what you see is in those + + align:start position:0% +and so what you see is in those + + + align:start position:0% +and so what you see is in those +electrodes right over there one two + + align:start position:0% +electrodes right over there one two + + + align:start position:0% +electrodes right over there one two +three that correspond to the ppa + + align:start position:0% +three that correspond to the ppa + + + align:start position:0% +three that correspond to the ppa +you see a higher response to house + + align:start position:0% +you see a higher response to house + + + align:start position:0% +you see a higher response to house +images than to any of the other images + + align:start position:0% +images than to any of the other images + + + align:start position:0% +images than to any of the other images +and you see the time course here over a + + align:start position:0% +and you see the time course here over a + + + align:start position:0% +and you see the time course here over a +few seconds + + align:start position:0% +few seconds + + + align:start position:0% +few seconds +okay everybody clear this is not causal + + align:start position:0% +okay everybody clear this is not causal + + + align:start position:0% +okay everybody clear this is not causal +evidence yet it's just amazing direct + + align:start position:0% +evidence yet it's just amazing direct + + + align:start position:0% +evidence yet it's just amazing direct +intracranial recordings from the ppa + + align:start position:0% +intracranial recordings from the ppa + + + align:start position:0% +intracranial recordings from the ppa +i think the only time this was ever done + + align:start position:0% +i think the only time this was ever done + + + align:start position:0% +i think the only time this was ever done +because it's pretty rare to have the + + align:start position:0% +because it's pretty rare to have the + + + align:start position:0% +because it's pretty rare to have the +electrodes right there in a patient + + align:start position:0% +electrodes right there in a patient + + + align:start position:0% +electrodes right there in a patient +who's willing to look at your silly + + align:start position:0% +who's willing to look at your silly + + + align:start position:0% +who's willing to look at your silly +pictures and all of that right + + align:start position:0% +pictures and all of that right + + + align:start position:0% +pictures and all of that right +okay + + align:start position:0% +okay + + + align:start position:0% +okay +but now + + align:start position:0% +but now + + + align:start position:0% +but now +what happens when they stimulate there + + align:start position:0% +what happens when they stimulate there + + + align:start position:0% +what happens when they stimulate there +okay so let's look at what happens when + + align:start position:0% +okay so let's look at what happens when + + + align:start position:0% +okay so let's look at what happens when +they stimulate + + align:start position:0% +they stimulate + + + align:start position:0% +they stimulate +um on these sites um + + align:start position:0% +um on these sites um + + + align:start position:0% +um on these sites um +four and three that are off to the side + + align:start position:0% +four and three that are off to the side + + + align:start position:0% +four and three that are off to the side +of the scene selectivity and this is + + align:start position:0% +of the scene selectivity and this is + + + align:start position:0% +of the scene selectivity and this is +just a dialogue we don't have a video + + align:start position:0% +just a dialogue we don't have a video + + + align:start position:0% +just a dialogue we don't have a video +unfortunately the videos are more fun + + align:start position:0% +unfortunately the videos are more fun + + + align:start position:0% +unfortunately the videos are more fun +but it's just a dialogue between the + + align:start position:0% +but it's just a dialogue between the + + + align:start position:0% +but it's just a dialogue between the +neurologist and the patient + + align:start position:0% +neurologist and the patient + + + align:start position:0% +neurologist and the patient +and the neurologist electrically + + align:start position:0% +and the neurologist electrically + + + align:start position:0% +and the neurologist electrically +stimulates that region + + align:start position:0% +stimulates that region + + + align:start position:0% +stimulates that region +and + + align:start position:0% +and + + + align:start position:0% +and +and says did you see anything there + + align:start position:0% +and says did you see anything there + + + align:start position:0% +and says did you see anything there +patient says i don't know i started + + align:start position:0% +patient says i don't know i started + + + align:start position:0% +patient says i don't know i started +feeling something i don't know it's + + align:start position:0% +feeling something i don't know it's + + + align:start position:0% +feeling something i don't know it's +probably just me oh no it's not you + + align:start position:0% +probably just me oh no it's not you + + + align:start position:0% +probably just me oh no it's not you +and then they stimulate again anything + + align:start position:0% +and then they stimulate again anything + + + align:start position:0% +and then they stimulate again anything +there no anything here no okay so that's + + align:start position:0% +there no anything here no okay so that's + + + align:start position:0% +there no anything here no okay so that's +right next to the side of the scene + + align:start position:0% +right next to the side of the scene + + + align:start position:0% +right next to the side of the scene +selective electrodes right next door a + + align:start position:0% +selective electrodes right next door a + + + align:start position:0% +selective electrodes right next door a +few millimeters away + + align:start position:0% +few millimeters away + + + align:start position:0% +few millimeters away +then they move uh their stimulator over + + align:start position:0% +then they move uh their stimulator over + + + align:start position:0% +then they move uh their stimulator over +here they don't move anything they just + + align:start position:0% +here they don't move anything they just + + + align:start position:0% +here they don't move anything they just +control where they're going to stimulate + + align:start position:0% +control where they're going to stimulate + + + align:start position:0% +control where they're going to stimulate +patient of course has no idea + + align:start position:0% +patient of course has no idea + + + align:start position:0% +patient of course has no idea +neurologist says anything here do you + + align:start position:0% +neurologist says anything here do you + + + align:start position:0% +neurologist says anything here do you +see anything + + align:start position:0% +see anything + + + align:start position:0% +see anything +feel anything + + align:start position:0% +feel anything + + + align:start position:0% +feel anything +patient says yeah i feel like he looks + + align:start position:0% +patient says yeah i feel like he looks + + + align:start position:0% +patient says yeah i feel like he looks +perplexed + + align:start position:0% +perplexed + + + align:start position:0% +perplexed +puts hand to forehead + + align:start position:0% +puts hand to forehead + + + align:start position:0% +puts hand to forehead +i feel like i saw like + + align:start position:0% +i feel like i saw like + + + align:start position:0% +i feel like i saw like +some other site we were at the train + + align:start position:0% +some other site we were at the train + + + align:start position:0% +some other site we were at the train +station + + align:start position:0% +station + + + align:start position:0% +station +neurologist cleverly says so it feels + + align:start position:0% +neurologist cleverly says so it feels + + + align:start position:0% +neurologist cleverly says so it feels +like you're at a train station + + align:start position:0% +like you're at a train station + + + align:start position:0% +like you're at a train station +patient says yeah + + align:start position:0% +patient says yeah + + + align:start position:0% +patient says yeah +outside the train station neurologist + + align:start position:0% +outside the train station neurologist + + + align:start position:0% +outside the train station neurologist +let me know if you get any sensation + + align:start position:0% +let me know if you get any sensation + + + align:start position:0% +let me know if you get any sensation +like that again + + align:start position:0% +like that again + + + align:start position:0% +like that again +it stimulates do you feel anything here + + align:start position:0% +it stimulates do you feel anything here + + + align:start position:0% +it stimulates do you feel anything here +no + + align:start position:0% +no + + + align:start position:0% +no +um + + align:start position:0% +um + + + align:start position:0% +um +and he does it again do you see the um + + align:start position:0% +and he does it again do you see the um + + + align:start position:0% +and he does it again do you see the um +do you see the the train station or did + + align:start position:0% +do you see the the train station or did + + + align:start position:0% +do you see the the train station or did +it oh did you see the train station or + + align:start position:0% +it oh did you see the train station or + + + align:start position:0% +it oh did you see the train station or +did it feel like you were at the train + + align:start position:0% +did it feel like you were at the train + + + align:start position:0% +did it feel like you were at the train +station + + align:start position:0% +station + + + align:start position:0% +station +patient i saw it + + align:start position:0% +patient i saw it + + + align:start position:0% +patient i saw it +right these are very sparse precious + + align:start position:0% +right these are very sparse precious + + + align:start position:0% +right these are very sparse precious +data but that's so telling it's not that + + align:start position:0% +data but that's so telling it's not that + + + align:start position:0% +data but that's so telling it's not that +he knew he was at the train station + + align:start position:0% +he knew he was at the train station + + + align:start position:0% +he knew he was at the train station +abstractly he saw it okay + + align:start position:0% +abstractly he saw it okay + + + align:start position:0% +abstractly he saw it okay +so then they stimulate again right on + + align:start position:0% +so then they stimulate again right on + + + align:start position:0% +so then they stimulate again right on +those + + align:start position:0% +those + + + align:start position:0% +those +scene selective regions the patient says + + align:start position:0% +scene selective regions the patient says + + + align:start position:0% +scene selective regions the patient says +again i saw almost like i don't know + + align:start position:0% +again i saw almost like i don't know + + + align:start position:0% +again i saw almost like i don't know +like i saw it was very brief neurologist + + align:start position:0% +like i saw it was very brief neurologist + + + align:start position:0% +like i saw it was very brief neurologist +says i'm going to show it to you one + + align:start position:0% +says i'm going to show it to you one + + + align:start position:0% +says i'm going to show it to you one +more time really what he means is i'm + + align:start position:0% +more time really what he means is i'm + + + align:start position:0% +more time really what he means is i'm +going to stimulate you in the same place + + align:start position:0% +going to stimulate you in the same place + + + align:start position:0% +going to stimulate you in the same place +one more time see if you can describe it + + align:start position:0% +one more time see if you can describe it + + + align:start position:0% +one more time see if you can describe it +any further um + + align:start position:0% +any further um + + + align:start position:0% +any further um +i'm going to give you one last time what + + align:start position:0% +i'm going to give you one last time what + + + align:start position:0% +i'm going to give you one last time what +do you think + + align:start position:0% +do you think + + + align:start position:0% +do you think +i don't really know what to make of it + + align:start position:0% +i don't really know what to make of it + + + align:start position:0% +i don't really know what to make of it +but i saw like another staircase + + align:start position:0% +but i saw like another staircase + + + align:start position:0% +but i saw like another staircase +the rest i couldn't make out + + align:start position:0% +the rest i couldn't make out + + + align:start position:0% +the rest i couldn't make out +but i saw a closet space but not this + + align:start position:0% +but i saw a closet space but not this + + + align:start position:0% +but i saw a closet space but not this +one he points to a closet door in the + + align:start position:0% +one he points to a closet door in the + + + align:start position:0% +one he points to a closet door in the +room + + align:start position:0% +room + + + align:start position:0% +room +that one was stuffed and it was blue + + align:start position:0% +that one was stuffed and it was blue + + + align:start position:0% +that one was stuffed and it was blue +have you seen it before it's a + + align:start position:0% +have you seen it before it's a + + + align:start position:0% +have you seen it before it's a +neurologist have you seen it before at + + align:start position:0% +neurologist have you seen it before at + + + align:start position:0% +neurologist have you seen it before at +some point in your life you think yeah i + + align:start position:0% +some point in your life you think yeah i + + + align:start position:0% +some point in your life you think yeah i +mean when i saw the train station + + align:start position:0% +mean when i saw the train station + + + align:start position:0% +mean when i saw the train station +train station you've been at yeah et + + align:start position:0% +train station you've been at yeah et + + + align:start position:0% +train station you've been at yeah et +cetera et cetera + + align:start position:0% +cetera et cetera + + + align:start position:0% +cetera et cetera +so + + align:start position:0% +so + + + align:start position:0% +so +it's not a lot of data but it's very + + align:start position:0% +it's not a lot of data but it's very + + + align:start position:0% +it's not a lot of data but it's very +compelling right what is the patient + + align:start position:0% +compelling right what is the patient + + + align:start position:0% +compelling right what is the patient +describing + + align:start position:0% +describing + + + align:start position:0% +describing +places that he's in that he sees + + align:start position:0% +places that he's in that he sees + + + align:start position:0% +places that he's in that he sees +and then he describes this closet space + + align:start position:0% +and then he describes this closet space + + + align:start position:0% +and then he describes this closet space +and its colors interestingly color + + align:start position:0% +and its colors interestingly color + + + align:start position:0% +and its colors interestingly color +regions are right next to scene region + + align:start position:0% +regions are right next to scene region + + + align:start position:0% +regions are right next to scene region +so that's kind of cool too + + align:start position:0% +so that's kind of cool too + + + align:start position:0% +so that's kind of cool too +right + + align:start position:0% +right + + + align:start position:0% +right +so + + align:start position:0% +so + + + align:start position:0% +so +it's causal evidence it's sparse ideally + + align:start position:0% +it's causal evidence it's sparse ideally + + + align:start position:0% +it's causal evidence it's sparse ideally +we'd like more in science but + + align:start position:0% +we'd like more in science but + + + align:start position:0% +we'd like more in science but +it's pretty cool + + align:start position:0% +it's pretty cool + + + align:start position:0% +it's pretty cool +yeah and all this far the patient is + + align:start position:0% +yeah and all this far the patient is + + + align:start position:0% +yeah and all this far the patient is +just staring at a bank + + align:start position:0% +just staring at a bank + + + align:start position:0% +just staring at a bank +you know i actually forget in the paper + + align:start position:0% +you know i actually forget in the paper + + + align:start position:0% +you know i actually forget in the paper +i've got to go look that up i forget + + align:start position:0% +i've got to go look that up i forget + + + align:start position:0% +i've got to go look that up i forget +exactly what the patient was doing + + align:start position:0% +exactly what the patient was doing + + + align:start position:0% +exactly what the patient was doing +whether i think he's just in the room + + align:start position:0% +whether i think he's just in the room + + + align:start position:0% +whether i think he's just in the room +looking out + + align:start position:0% +looking out + + + align:start position:0% +looking out +usually they don't control it that much + + align:start position:0% +usually they don't control it that much + + + align:start position:0% +usually they don't control it that much +because it's done kind of for clinical + + align:start position:0% +because it's done kind of for clinical + + + align:start position:0% +because it's done kind of for clinical +reasons and the patient is in their + + align:start position:0% +reasons and the patient is in their + + + align:start position:0% +reasons and the patient is in their +hospital bed and they're just + + align:start position:0% +hospital bed and they're just + + + align:start position:0% +hospital bed and they're just +stimulating so he's probably just + + align:start position:0% +stimulating so he's probably just + + + align:start position:0% +stimulating so he's probably just +looking out at the space he's in in fact + + align:start position:0% +looking out at the space he's in in fact + + + align:start position:0% +looking out at the space he's in in fact +he must have been because at one point + + align:start position:0% +he must have been because at one point + + + align:start position:0% +he must have been because at one point +he says a closet not like that one over + + align:start position:0% +he says a closet not like that one over + + + align:start position:0% +he says a closet not like that one over +there so if he was staring at a blank + + align:start position:0% +there so if he was staring at a blank + + + align:start position:0% +there so if he was staring at a blank +thing he was also + + align:start position:0% +thing he was also + + + align:start position:0% +thing he was also +looking out at his room + + align:start position:0% +looking out at his room + + + align:start position:0% +looking out at his room +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so + + align:start position:0% +so + + + align:start position:0% +so +yeah so + + align:start position:0% +yeah so + + + align:start position:0% +yeah so +this may be a little bit off topic you + + align:start position:0% +this may be a little bit off topic you + + + align:start position:0% +this may be a little bit off topic you +said the region of color perception is + + align:start position:0% +said the region of color perception is + + + align:start position:0% +said the region of color perception is +very close to this + + align:start position:0% +very close to this + + + align:start position:0% +very close to this +is there any relationship between like + + align:start position:0% +is there any relationship between like + + + align:start position:0% +is there any relationship between like +functional proximity and + + align:start position:0% +functional proximity and + + + align:start position:0% +functional proximity and +that's a great question nobody in the + + align:start position:0% +that's a great question nobody in the + + + align:start position:0% +that's a great question nobody in the +field has an answer to this people often + + align:start position:0% +field has an answer to this people often + + + align:start position:0% +field has an answer to this people often +make hay about the proximity of two + + align:start position:0% +make hay about the proximity of two + + + align:start position:0% +make hay about the proximity of two +regions like oh there's some deep link + + align:start position:0% +regions like oh there's some deep link + + + align:start position:0% +regions like oh there's some deep link +because this thing is next to that thing + + align:start position:0% +because this thing is next to that thing + + + align:start position:0% +because this thing is next to that thing +uh you know the body selective region is + + align:start position:0% +uh you know the body selective region is + + + align:start position:0% +uh you know the body selective region is +right next to and in fact slightly + + align:start position:0% +right next to and in fact slightly + + + align:start position:0% +right next to and in fact slightly +overlapping with uh area mt that + + align:start position:0% +overlapping with uh area mt that + + + align:start position:0% +overlapping with uh area mt that +responds to motion it's like oh bodies + + align:start position:0% +responds to motion it's like oh bodies + + + align:start position:0% +responds to motion it's like oh bodies +you know faces move and cars move too so + + align:start position:0% +you know faces move and cars move too so + + + align:start position:0% +you know faces move and cars move too so +you know like i don't know it's + + align:start position:0% +you know like i don't know it's + + + align:start position:0% +you know like i don't know it's +tantalizing it feels like it ought to + + align:start position:0% +tantalizing it feels like it ought to + + + align:start position:0% +tantalizing it feels like it ought to +mean something and people often talk + + align:start position:0% +mean something and people often talk + + + align:start position:0% +mean something and people often talk +about you know talk as if it does and + + align:start position:0% +about you know talk as if it does and + + + align:start position:0% +about you know talk as if it does and +maybe it does but nobody's really put + + align:start position:0% +maybe it does but nobody's really put + + + align:start position:0% +maybe it does but nobody's really put +their finger on what exactly it would + + align:start position:0% +their finger on what exactly it would + + + align:start position:0% +their finger on what exactly it would +mean + + align:start position:0% + + + + align:start position:0% + +but it's useful right so when when rosa + + align:start position:0% +but it's useful right so when when rosa + + + align:start position:0% +but it's useful right so when when rosa +lay for souza who you met in the color + + align:start position:0% +lay for souza who you met in the color + + + align:start position:0% +lay for souza who you met in the color +demo + + align:start position:0% +demo + + + align:start position:0% +demo +and i showed that in + + align:start position:0% +and i showed that in + + + align:start position:0% +and i showed that in +in humans you get face color and place + + align:start position:0% +in humans you get face color and place + + + align:start position:0% +in humans you get face color and place +regions right next to each other in that + + align:start position:0% +regions right next to each other in that + + + align:start position:0% +regions right next to each other in that +order that was really cool because rosa + + align:start position:0% +order that was really cool because rosa + + + align:start position:0% +order that was really cool because rosa +had previously shown that in monkeys + + align:start position:0% +had previously shown that in monkeys + + + align:start position:0% +had previously shown that in monkeys +in the monkey brain it goes face color + + align:start position:0% +in the monkey brain it goes face color + + + align:start position:0% +in the monkey brain it goes face color +place in exactly the same order + + align:start position:0% +place in exactly the same order + + + align:start position:0% +place in exactly the same order +and so we thought okay that's really + + align:start position:0% +and so we thought okay that's really + + + align:start position:0% +and so we thought okay that's really +interesting that suggests common + + align:start position:0% +interesting that suggests common + + + align:start position:0% +interesting that suggests common +inheritance because that's so weird and + + align:start position:0% +inheritance because that's so weird and + + + align:start position:0% +inheritance because that's so weird and +arbitrary why would it be the same so it + + align:start position:0% +arbitrary why would it be the same so it + + + align:start position:0% +arbitrary why would it be the same so it +can be useful in ways like that + + align:start position:0% +can be useful in ways like that + + + align:start position:0% +can be useful in ways like that +at least + + align:start position:0% +at least + + + align:start position:0% +at least +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so we just went through all of this so + + align:start position:0% +so we just went through all of this so + + + align:start position:0% +so we just went through all of this so +how does this go beyond what we knew + + align:start position:0% +how does this go beyond what we knew + + + align:start position:0% +how does this go beyond what we knew +from functional mri + + align:start position:0% +from functional mri + + + align:start position:0% +from functional mri +i'm insulting your intelligence you know + + align:start position:0% +i'm insulting your intelligence you know + + + align:start position:0% +i'm insulting your intelligence you know +the answer to this it goes beyond it + + align:start position:0% +the answer to this it goes beyond it + + + align:start position:0% +the answer to this it goes beyond it +because it tells you it implies that + + align:start position:0% +because it tells you it implies that + + + align:start position:0% +because it tells you it implies that +there's a causal role of that region in + + align:start position:0% +there's a causal role of that region in + + + align:start position:0% +there's a causal role of that region in +place perception some aspect of + + align:start position:0% +place perception some aspect of + + + align:start position:0% +place perception some aspect of +seeing a place okay + + align:start position:0% +seeing a place okay + + + align:start position:0% +seeing a place okay +now all of this about the ppa i just + + align:start position:0% +now all of this about the ppa i just + + + align:start position:0% +now all of this about the ppa i just +started in there because it's nice and + + align:start position:0% +started in there because it's nice and + + + align:start position:0% +started in there because it's nice and +concrete and easy to think about but no + + align:start position:0% +concrete and easy to think about but no + + + align:start position:0% +concrete and easy to think about but no +complex mental process happens in just + + align:start position:0% +complex mental process happens in just + + + align:start position:0% +complex mental process happens in just +one brain region nothing is ever like + + align:start position:0% +one brain region nothing is ever like + + + align:start position:0% +one brain region nothing is ever like +that + + align:start position:0% +that + + + align:start position:0% +that +uh and likewise scene perception and + + align:start position:0% +uh and likewise scene perception and + + + align:start position:0% +uh and likewise scene perception and +navigation is part of a much broader set + + align:start position:0% +navigation is part of a much broader set + + + align:start position:0% +navigation is part of a much broader set +of regions so if you do a contrast scan + + align:start position:0% +of regions so if you do a contrast scan + + + align:start position:0% +of regions so if you do a contrast scan +people looking at scenes versus objects + + align:start position:0% +people looking at scenes versus objects + + + align:start position:0% +people looking at scenes versus objects +you'll see not just the ppa in here + + align:start position:0% +you'll see not just the ppa in here + + + align:start position:0% +you'll see not just the ppa in here +again this is a folded up brain and this + + align:start position:0% +again this is a folded up brain and this + + + align:start position:0% +again this is a folded up brain and this +is the mathematically unfolded version + + align:start position:0% +is the mathematically unfolded version + + + align:start position:0% +is the mathematically unfolded version +so you can see the whole cortex dark + + align:start position:0% +so you can see the whole cortex dark + + + align:start position:0% +so you can see the whole cortex dark +bits are the bits that were that used to + + align:start position:0% +bits are the bits that were that used to + + + align:start position:0% +bits are the bits that were that used to +be inside a sulcus until it was + + align:start position:0% +be inside a sulcus until it was + + + align:start position:0% +be inside a sulcus until it was +mathematically unfolded + + align:start position:0% +mathematically unfolded + + + align:start position:0% +mathematically unfolded +so there's the ppa kind of hiding up in + + align:start position:0% +so there's the ppa kind of hiding up in + + + align:start position:0% +so there's the ppa kind of hiding up in +that sulcus and when you unfold it you + + align:start position:0% +that sulcus and when you unfold it you + + + align:start position:0% +that sulcus and when you unfold it you +see this nice big huge region okay + + align:start position:0% +see this nice big huge region okay + + + align:start position:0% +see this nice big huge region okay +but you also see all these other regions + + align:start position:0% +but you also see all these other regions + + + align:start position:0% +but you also see all these other regions +okay now there's a bunch of terminology + + align:start position:0% +okay now there's a bunch of terminology + + + align:start position:0% +okay now there's a bunch of terminology +and i don't panic i don't think you + + align:start position:0% +and i don't panic i don't think you + + + align:start position:0% +and i don't panic i don't think you +should memorize everything about each + + align:start position:0% +should memorize everything about each + + + align:start position:0% +should memorize everything about each +region you should know that there's + + align:start position:0% +region you should know that there's + + + align:start position:0% +region you should know that there's +multiple scene regions you should know + + align:start position:0% +multiple scene regions you should know + + + align:start position:0% +multiple scene regions you should know +some of the kinds of ways you tease + + align:start position:0% +some of the kinds of ways you tease + + + align:start position:0% +some of the kinds of ways you tease +apart the functions and some of the + + align:start position:0% +apart the functions and some of the + + + align:start position:0% +apart the functions and some of the +functions that have been + + align:start position:0% +functions that have been + + + align:start position:0% +functions that have been +tested and how they're tested but you + + align:start position:0% +tested and how they're tested but you + + + align:start position:0% +tested and how they're tested but you +don't need to memorize every last detail + + align:start position:0% +don't need to memorize every last detail + + + align:start position:0% +don't need to memorize every last detail +okay + + align:start position:0% +okay + + + align:start position:0% +okay +because it's going to get a little hairy + + align:start position:0% +because it's going to get a little hairy + + + align:start position:0% +because it's going to get a little hairy +okay so here's a second scene region + + align:start position:0% +okay so here's a second scene region + + + align:start position:0% +okay so here's a second scene region +right there + + align:start position:0% +right there + + + align:start position:0% +right there +called retrosplenial cortex or rsc + + align:start position:0% +called retrosplenial cortex or rsc + + + align:start position:0% +called retrosplenial cortex or rsc +and uh actually russell epstein and i + + align:start position:0% +and uh actually russell epstein and i + + + align:start position:0% +and uh actually russell epstein and i +saw that activation in the very very + + align:start position:0% +saw that activation in the very very + + + align:start position:0% +saw that activation in the very very +first experiments we did in the 1990s + + align:start position:0% +first experiments we did in the 1990s + + + align:start position:0% +first experiments we did in the 1990s +but we really didn't know what we were + + align:start position:0% +but we really didn't know what we were + + + align:start position:0% +but we really didn't know what we were +doing back then and we knew that this is + + align:start position:0% +doing back then and we knew that this is + + + align:start position:0% +doing back then and we knew that this is +right near the calcarine sulcus + + align:start position:0% +right near the calcarine sulcus + + + align:start position:0% +right near the calcarine sulcus +remind me what happens in the calculus + + align:start position:0% +remind me what happens in the calculus + + + align:start position:0% +remind me what happens in the calculus +sulcus what functional region lives in + + align:start position:0% +sulcus what functional region lives in + + + align:start position:0% +sulcus what functional region lives in +the calcren sulcus + + align:start position:0% + + + + align:start position:0% + +it's just a weird little fact but it's + + align:start position:0% +it's just a weird little fact but it's + + + align:start position:0% +it's just a weird little fact but it's +kind of an important one + + align:start position:0% +kind of an important one + + + align:start position:0% +kind of an important one +that we mentioned weeks ago + + align:start position:0% +that we mentioned weeks ago + + + align:start position:0% +that we mentioned weeks ago +v1 primary visual cortex + + align:start position:0% +v1 primary visual cortex + + + align:start position:0% +v1 primary visual cortex +that's where primary visual cortex lives + + align:start position:0% +that's where primary visual cortex lives + + + align:start position:0% +that's where primary visual cortex lives +and remember primary visual cortex + + align:start position:0% +and remember primary visual cortex + + + align:start position:0% +and remember primary visual cortex +has a map of retinotopic space with + + align:start position:0% +has a map of retinotopic space with + + + align:start position:0% +has a map of retinotopic space with +next-door bits of primary visual cortex + + align:start position:0% +next-door bits of primary visual cortex + + + align:start position:0% +next-door bits of primary visual cortex +responding to next-door bits of space + + align:start position:0% +responding to next-door bits of space + + + align:start position:0% +responding to next-door bits of space +and in fact that map has the center of + + align:start position:0% +and in fact that map has the center of + + + align:start position:0% +and in fact that map has the center of +gaze out here and the periphery out + + align:start position:0% +gaze out here and the periphery out + + + align:start position:0% +gaze out here and the periphery out +there + + align:start position:0% +there + + + align:start position:0% +there +so when russell and i first saw that + + align:start position:0% +so when russell and i first saw that + + + align:start position:0% +so when russell and i first saw that +activation we had the same worry that + + align:start position:0% +activation we had the same worry that + + + align:start position:0% +activation we had the same worry that +quilley mentioned a while back and that + + align:start position:0% +quilley mentioned a while back and that + + + align:start position:0% +quilley mentioned a while back and that +is the scenes are sticking out there's + + align:start position:0% +is the scenes are sticking out there's + + + align:start position:0% +is the scenes are sticking out there's +stuff everywhere the objects there isn't + + align:start position:0% +stuff everywhere the objects there isn't + + + align:start position:0% +stuff everywhere the objects there isn't +that much sticking out and we thought oh + + align:start position:0% +that much sticking out and we thought oh + + + align:start position:0% +that much sticking out and we thought oh +that's just peripheral retina topic + + align:start position:0% +that's just peripheral retina topic + + + align:start position:0% +that's just peripheral retina topic +cortex but it's not it's right next to + + align:start position:0% +cortex but it's not it's right next to + + + align:start position:0% +cortex but it's not it's right next to +there and it's a totally different thing + + align:start position:0% +there and it's a totally different thing + + + align:start position:0% +there and it's a totally different thing +and it turns out to be extremely + + align:start position:0% +and it turns out to be extremely + + + align:start position:0% +and it turns out to be extremely +interesting + + align:start position:0% +interesting + + + align:start position:0% +interesting +you don't need to know all that it's + + align:start position:0% +you don't need to know all that it's + + + align:start position:0% +you don't need to know all that it's +just silly little history + + align:start position:0% +just silly little history + + + align:start position:0% +just silly little history +okay there's a third region up there + + align:start position:0% +okay there's a third region up there + + + align:start position:0% +okay there's a third region up there +that's on the outer surface out there + + align:start position:0% +that's on the outer surface out there + + + align:start position:0% +that's on the outer surface out there +um that used to be called tos and now is + + align:start position:0% +um that used to be called tos and now is + + + align:start position:0% +um that used to be called tos and now is +now called opa i'm sorry about that you + + align:start position:0% +now called opa i'm sorry about that you + + + align:start position:0% +now called opa i'm sorry about that you +don't need to remember this know that + + align:start position:0% +don't need to remember this know that + + + align:start position:0% +don't need to remember this know that +there's not there are at least three + + align:start position:0% +there's not there are at least three + + + align:start position:0% +there's not there are at least three +regions + + align:start position:0% +regions + + + align:start position:0% +regions +um + + align:start position:0% +um + + + align:start position:0% +um +what but t os opa is interesting because + + align:start position:0% +what but t os opa is interesting because + + + align:start position:0% +what but t os opa is interesting because +there's a method we can apply + + align:start position:0% +there's a method we can apply + + + align:start position:0% +there's a method we can apply +to it that we can't apply to the others + + align:start position:0% +to it that we can't apply to the others + + + align:start position:0% +to it that we can't apply to the others +what would that method be + + align:start position:0% + + + + align:start position:0% + +yeah tms it's right out on the surface + + align:start position:0% +yeah tms it's right out on the surface + + + align:start position:0% +yeah tms it's right out on the surface +you just stick the coil there and go zap + + align:start position:0% +you just stick the coil there and go zap + + + align:start position:0% +you just stick the coil there and go zap +so of course + + align:start position:0% +so of course + + + align:start position:0% +so of course +we've done a lot of that okay you can't + + align:start position:0% +we've done a lot of that okay you can't + + + align:start position:0% +we've done a lot of that okay you can't +get the coil into the ppa or rsc it's + + align:start position:0% +get the coil into the ppa or rsc it's + + + align:start position:0% +get the coil into the ppa or rsc it's +too medial + + align:start position:0% +too medial + + + align:start position:0% +too medial +all right + + align:start position:0% +all right + + + align:start position:0% +all right +okay and there's another region that + + align:start position:0% +okay and there's another region that + + + align:start position:0% +okay and there's another region that +we'll talk about more next time called + + align:start position:0% +we'll talk about more next time called + + + align:start position:0% +we'll talk about more next time called +the hippocampus you saw the hippocampus + + align:start position:0% +the hippocampus you saw the hippocampus + + + align:start position:0% +the hippocampus you saw the hippocampus +when ann graybill spent all that time + + align:start position:0% +when ann graybill spent all that time + + + align:start position:0% +when ann graybill spent all that time +digging in the temporal lobe to find + + align:start position:0% +digging in the temporal lobe to find + + + align:start position:0% +digging in the temporal lobe to find +that bumpy little dentite gyrus + + align:start position:0% +that bumpy little dentite gyrus + + + align:start position:0% +that bumpy little dentite gyrus +approximately right in there + + align:start position:0% +approximately right in there + + + align:start position:0% +approximately right in there +and so all of these and probably other + + align:start position:0% +and so all of these and probably other + + + align:start position:0% +and so all of these and probably other +regions but these are the core elements + + align:start position:0% +regions but these are the core elements + + + align:start position:0% +regions but these are the core elements +of the + + align:start position:0% +of the + + + align:start position:0% +of the +of the scene selective regions that are + + align:start position:0% +of the scene selective regions that are + + + align:start position:0% +of the scene selective regions that are +implicated in different aspects of + + align:start position:0% +implicated in different aspects of + + + align:start position:0% +implicated in different aspects of +navigation + + align:start position:0% +navigation + + + align:start position:0% +navigation +okay so when you have + + align:start position:0% +okay so when you have + + + align:start position:0% +okay so when you have +multiple regions that seem to be part of + + align:start position:0% +multiple regions that seem to be part of + + + align:start position:0% +multiple regions that seem to be part of +a system that's an opportunity + + align:start position:0% +a system that's an opportunity + + + align:start position:0% +a system that's an opportunity +because now we have the possibility that + + align:start position:0% +because now we have the possibility that + + + align:start position:0% +because now we have the possibility that +maybe we could figure out different + + align:start position:0% +maybe we could figure out different + + + align:start position:0% +maybe we could figure out different +functions for different regions and then + + align:start position:0% +functions for different regions and then + + + align:start position:0% +functions for different regions and then +maybe that would really tell us more + + align:start position:0% +maybe that would really tell us more + + + align:start position:0% +maybe that would really tell us more +than just okay scenes and navigation end + + align:start position:0% +than just okay scenes and navigation end + + + align:start position:0% +than just okay scenes and navigation end +of story it's kind of rude of entry + + align:start position:0% +of story it's kind of rude of entry + + + align:start position:0% +of story it's kind of rude of entry +right it'll be nice if different aspects + + align:start position:0% +right it'll be nice if different aspects + + + align:start position:0% +right it'll be nice if different aspects +of the navigation story + + align:start position:0% +of the navigation story + + + align:start position:0% +of the navigation story +engage different parts of the system + + align:start position:0% +engage different parts of the system + + + align:start position:0% +engage different parts of the system +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so really what we want to know is how + + align:start position:0% +so really what we want to know is how + + + align:start position:0% +so really what we want to know is how +does each of these regions help us + + align:start position:0% +does each of these regions help us + + + align:start position:0% +does each of these regions help us +navigate and see scenes + + align:start position:0% +navigate and see scenes + + + align:start position:0% +navigate and see scenes +and i'm not going to answer that fully + + align:start position:0% +and i'm not going to answer that fully + + + align:start position:0% +and i'm not going to answer that fully +we're still what the the field is still + + align:start position:0% +we're still what the the field is still + + + align:start position:0% +we're still what the the field is still +trying to understand all of this but + + align:start position:0% +trying to understand all of this but + + + align:start position:0% +trying to understand all of this but +i'll give you a few tantalizing little + + align:start position:0% +i'll give you a few tantalizing little + + + align:start position:0% +i'll give you a few tantalizing little +snippets okay + + align:start position:0% +snippets okay + + + align:start position:0% +snippets okay +so let's take retrosplenial cortex right + + align:start position:0% +so let's take retrosplenial cortex right + + + align:start position:0% +so let's take retrosplenial cortex right +here + + align:start position:0% +here + + + align:start position:0% +here +so um richard so this is first the + + align:start position:0% +so um richard so this is first the + + + align:start position:0% +so um richard so this is first the +response of the ppa right there in + + align:start position:0% +response of the ppa right there in + + + align:start position:0% +response of the ppa right there in +retrospective cortex which is just + + align:start position:0% +retrospective cortex which is just + + + align:start position:0% +retrospective cortex which is just +behind it + + align:start position:0% +behind it + + + align:start position:0% +behind it +this is just its mean response to a + + align:start position:0% +this is just its mean response to a + + + align:start position:0% +this is just its mean response to a +bunch of different kinds of stimuli + + align:start position:0% +bunch of different kinds of stimuli + + + align:start position:0% +bunch of different kinds of stimuli +showing the you that it likes landscapes + + align:start position:0% +showing the you that it likes landscapes + + + align:start position:0% +showing the you that it likes landscapes +and cityscapes scenes more than a bunch + + align:start position:0% +and cityscapes scenes more than a bunch + + + align:start position:0% +and cityscapes scenes more than a bunch +of other categories of objects and + + align:start position:0% +of other categories of objects and + + + align:start position:0% +of other categories of objects and +that's true of both the ppa and rsc + + align:start position:0% +that's true of both the ppa and rsc + + + align:start position:0% +that's true of both the ppa and rsc +okay no surprises here they're both + + align:start position:0% +okay no surprises here they're both + + + align:start position:0% +okay no surprises here they're both +somewhat seen selective + + align:start position:0% +somewhat seen selective + + + align:start position:0% +somewhat seen selective +okay + + align:start position:0% +okay + + + align:start position:0% +okay +but then in a whole bunch of other + + align:start position:0% +but then in a whole bunch of other + + + align:start position:0% +but then in a whole bunch of other +studies + + align:start position:0% +studies + + + align:start position:0% +studies +summarized in this graph here + + align:start position:0% +summarized in this graph here + + + align:start position:0% +summarized in this graph here +russell epstein and his colleagues + + align:start position:0% +russell epstein and his colleagues + + + align:start position:0% +russell epstein and his colleagues +had subjects engage in different tasks + + align:start position:0% +had subjects engage in different tasks + + + align:start position:0% +had subjects engage in different tasks +while they were looking at scenes in + + align:start position:0% +while they were looking at scenes in + + + align:start position:0% +while they were looking at scenes in +some tasks they had to say where they + + align:start position:0% +some tasks they had to say where they + + + align:start position:0% +some tasks they had to say where they +were + + align:start position:0% +were + + + align:start position:0% +were +he's at u pen and he showed his subjects + + align:start position:0% +he's at u pen and he showed his subjects + + + align:start position:0% +he's at u pen and he showed his subjects +pictures of the eupan campus and they + + align:start position:0% +pictures of the eupan campus and they + + + align:start position:0% +pictures of the eupan campus and they +had to answer all kinds of questions + + align:start position:0% +had to answer all kinds of questions + + + align:start position:0% +had to answer all kinds of questions +about + + align:start position:0% +about + + + align:start position:0% +about +what part of campus they were where they + + align:start position:0% +what part of campus they were where they + + + align:start position:0% +what part of campus they were where they +were in on campus and also about which + + align:start position:0% +were in on campus and also about which + + + align:start position:0% +were in on campus and also about which +way they were facing given the view of + + align:start position:0% +way they were facing given the view of + + + align:start position:0% +way they were facing given the view of +the campus they were looking at + + align:start position:0% +the campus they were looking at + + + align:start position:0% +the campus they were looking at +okay + + align:start position:0% +okay + + + align:start position:0% +okay +then he also showed people familiar + + align:start position:0% +then he also showed people familiar + + + align:start position:0% +then he also showed people familiar +scenes and unfamiliar scenes much like + + align:start position:0% +scenes and unfamiliar scenes much like + + + align:start position:0% +scenes and unfamiliar scenes much like +we did with our tough study + + align:start position:0% +we did with our tough study + + + align:start position:0% +we did with our tough study +and he had object controls + + align:start position:0% +and he had object controls + + + align:start position:0% +and he had object controls +and you can see the ppa doesn't care + + align:start position:0% +and you can see the ppa doesn't care + + + align:start position:0% +and you can see the ppa doesn't care +about any of that doesn't care really if + + align:start position:0% +about any of that doesn't care really if + + + align:start position:0% +about any of that doesn't care really if +they're familiar or unfamiliar doesn't + + align:start position:0% +they're familiar or unfamiliar doesn't + + + align:start position:0% +they're familiar or unfamiliar doesn't +care what task you're doing on the scene + + align:start position:0% +care what task you're doing on the scene + + + align:start position:0% +care what task you're doing on the scene +you're looking at a scene it's just + + align:start position:0% +you're looking at a scene it's just + + + align:start position:0% +you're looking at a scene it's just +going + + align:start position:0% +going + + + align:start position:0% +going +okay so we we didn't really tease of + + align:start position:0% +okay so we we didn't really tease of + + + align:start position:0% +okay so we we didn't really tease of +heart functions there + + align:start position:0% +heart functions there + + + align:start position:0% +heart functions there +but + + align:start position:0% +but + + + align:start position:0% +but +rsc responds differently in these + + align:start position:0% +rsc responds differently in these + + + align:start position:0% +rsc responds differently in these +conditions + + align:start position:0% +conditions + + + align:start position:0% +conditions +it's more um + + align:start position:0% +it's more um + + + align:start position:0% +it's more um +it's engaged in both the location task + + align:start position:0% +it's engaged in both the location task + + + align:start position:0% +it's engaged in both the location task +and the orientation task + + align:start position:0% +and the orientation task + + + align:start position:0% +and the orientation task +um it's um it doesn't oh it responds + + align:start position:0% +um it's um it doesn't oh it responds + + + align:start position:0% +um it's um it doesn't oh it responds +substantially more + + align:start position:0% +substantially more + + + align:start position:0% +substantially more +when you look at images of a familiar + + align:start position:0% +when you look at images of a familiar + + + align:start position:0% +when you look at images of a familiar +place than an unfamiliar place so this + + align:start position:0% +place than an unfamiliar place so this + + + align:start position:0% +place than an unfamiliar place so this +is the first time we've seen that in the + + align:start position:0% +is the first time we've seen that in the + + + align:start position:0% +is the first time we've seen that in the +scene network and so now think about all + + align:start position:0% +scene network and so now think about all + + + align:start position:0% +scene network and so now think about all +the things you can do when you're + + align:start position:0% +the things you can do when you're + + + align:start position:0% +the things you can do when you're +looking at a picture of a scene and you + + align:start position:0% +looking at a picture of a scene and you + + + align:start position:0% +looking at a picture of a scene and you +know that place + + align:start position:0% +know that place + + + align:start position:0% +know that place +you have memories of having been there + + align:start position:0% +you have memories of having been there + + + align:start position:0% +you have memories of having been there +you can think about you know what you + + align:start position:0% +you can think about you know what you + + + align:start position:0% +you can think about you know what you +might do if you were there how you would + + align:start position:0% +might do if you were there how you would + + + align:start position:0% +might do if you were there how you would +get from there to some place else all of + + align:start position:0% +get from there to some place else all of + + + align:start position:0% +get from there to some place else all of +those things are possible things that + + align:start position:0% +those things are possible things that + + + align:start position:0% +those things are possible things that +might be driving + + align:start position:0% +might be driving + + + align:start position:0% +might be driving +rsc + + align:start position:0% + + + + align:start position:0% + +another thing that might be driving rsc + + align:start position:0% +another thing that might be driving rsc + + + align:start position:0% +another thing that might be driving rsc +is that if you're looking at a picture + + align:start position:0% +is that if you're looking at a picture + + + align:start position:0% +is that if you're looking at a picture +of a familiar place + + align:start position:0% +of a familiar place + + + align:start position:0% +of a familiar place +you orient yourself with respect to the + + align:start position:0% +you orient yourself with respect to the + + + align:start position:0% +you orient yourself with respect to the +broader environment that that view is + + align:start position:0% +broader environment that that view is + + + align:start position:0% +broader environment that that view is +part of + + align:start position:0% +part of + + + align:start position:0% +part of +right so when i showed you that picture + + align:start position:0% +right so when i showed you that picture + + + align:start position:0% +right so when i showed you that picture +of the front of stata you immediately + + align:start position:0% +of the front of stata you immediately + + + align:start position:0% +of the front of stata you immediately +imagine oh like i'm out on vassar street + + align:start position:0% +imagine oh like i'm out on vassar street + + + align:start position:0% +imagine oh like i'm out on vassar street +facing that way roughly + + align:start position:0% +facing that way roughly + + + align:start position:0% +facing that way roughly +northwest i think + + align:start position:0% +northwest i think + + + align:start position:0% +northwest i think +okay + + align:start position:0% +okay + + + align:start position:0% +okay +if you look at a picture of a scene you + + align:start position:0% +if you look at a picture of a scene you + + + align:start position:0% +if you look at a picture of a scene you +don't know that scene it doesn't tell + + align:start position:0% +don't know that scene it doesn't tell + + + align:start position:0% +don't know that scene it doesn't tell +you anything about your broader heading + + align:start position:0% +you anything about your broader heading + + + align:start position:0% +you anything about your broader heading +in the in the broader world okay so all + + align:start position:0% +in the in the broader world okay so all + + + align:start position:0% +in the in the broader world okay so all +of those are things that + + align:start position:0% +of those are things that + + + align:start position:0% +of those are things that +the rsc + + align:start position:0% +the rsc + + + align:start position:0% +the rsc +its function seems to depend on knowing + + align:start position:0% +its function seems to depend on knowing + + + align:start position:0% +its function seems to depend on knowing +that place + + align:start position:0% +that place + + + align:start position:0% +that place +okay + + align:start position:0% + + + + align:start position:0% + +perhaps the most telling case comes from + + align:start position:0% +perhaps the most telling case comes from + + + align:start position:0% +perhaps the most telling case comes from +a patient who had damage in + + align:start position:0% +a patient who had damage in + + + align:start position:0% +a patient who had damage in +retrosplenial cortex + + align:start position:0% +retrosplenial cortex + + + align:start position:0% +retrosplenial cortex +and the description in the paper of this + + align:start position:0% +and the description in the paper of this + + + align:start position:0% +and the description in the paper of this +says that this patient + + align:start position:0% +says that this patient + + + align:start position:0% +says that this patient +could recognize buildings and the and + + align:start position:0% +could recognize buildings and the and + + + align:start position:0% +could recognize buildings and the and +the landmarks and therefore understand + + align:start position:0% +the landmarks and therefore understand + + + align:start position:0% +the landmarks and therefore understand +where he was + + align:start position:0% +where he was + + + align:start position:0% +where he was +okay so lots is intact can recognize + + align:start position:0% +okay so lots is intact can recognize + + + align:start position:0% +okay so lots is intact can recognize +scenes and know where he is + + align:start position:0% +scenes and know where he is + + + align:start position:0% +scenes and know where he is +but the landmarks he recognized did not + + align:start position:0% +but the landmarks he recognized did not + + + align:start position:0% +but the landmarks he recognized did not +provoke directional information about + + align:start position:0% +provoke directional information about + + + align:start position:0% +provoke directional information about +any other places with respect to those + + align:start position:0% +any other places with respect to those + + + align:start position:0% +any other places with respect to those +landmarks + + align:start position:0% +landmarks + + + align:start position:0% +landmarks +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so this person can look at a picture and + + align:start position:0% +so this person can look at a picture and + + + align:start position:0% +so this person can look at a picture and +say yeah i know that place you know + + align:start position:0% +say yeah i know that place you know + + + align:start position:0% +say yeah i know that place you know +that's the front of my house + + align:start position:0% +that's the front of my house + + + align:start position:0% +that's the front of my house +but then if you say you know in which + + align:start position:0% +but then if you say you know in which + + + align:start position:0% +but then if you say you know in which +direction is you know a coffee shop two + + align:start position:0% +direction is you know a coffee shop two + + + align:start position:0% +direction is you know a coffee shop two +blocks away + + align:start position:0% +blocks away + + + align:start position:0% +blocks away +he doesn't know which way it is from + + align:start position:0% +he doesn't know which way it is from + + + align:start position:0% +he doesn't know which way it is from +there + + align:start position:0% +there + + + align:start position:0% +there +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so um this should sound familiar + + align:start position:0% +so um this should sound familiar + + + align:start position:0% +so um this should sound familiar +this is my guess of the bit that my + + align:start position:0% +this is my guess of the bit that my + + + align:start position:0% +this is my guess of the bit that my +friend bob + + align:start position:0% +friend bob + + + align:start position:0% +friend bob +got messed up + + align:start position:0% +got messed up + + + align:start position:0% +got messed up +yeah this is exactly his description he + + align:start position:0% +yeah this is exactly his description he + + + align:start position:0% +yeah this is exactly his description he +could recognize places but it wouldn't + + align:start position:0% +could recognize places but it wouldn't + + + align:start position:0% +could recognize places but it wouldn't +tell him how to get from there to + + align:start position:0% +tell him how to get from there to + + + align:start position:0% +tell him how to get from there to +somewhere else + + align:start position:0% +somewhere else + + + align:start position:0% +somewhere else +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and so the best current guess about + + align:start position:0% +and so the best current guess about + + + align:start position:0% +and so the best current guess about +retrospinal cortex is it is involved in + + align:start position:0% +retrospinal cortex is it is involved in + + + align:start position:0% +retrospinal cortex is it is involved in +you know anchoring where you are you + + align:start position:0% +you know anchoring where you are you + + + align:start position:0% +you know anchoring where you are you +have this mental map of the world + + align:start position:0% +have this mental map of the world + + + align:start position:0% +have this mental map of the world +and you have a scene and you're trying + + align:start position:0% +and you have a scene and you're trying + + + align:start position:0% +and you have a scene and you're trying +to put them together given that i see + + align:start position:0% +to put them together given that i see + + + align:start position:0% +to put them together given that i see +this + + align:start position:0% +this + + + align:start position:0% +this +where am i on the map and which way am i + + align:start position:0% +where am i on the map and which way am i + + + align:start position:0% +where am i on the map and which way am i +heading in that map + + align:start position:0% +heading in that map + + + align:start position:0% +heading in that map +okay + + align:start position:0% +okay + + + align:start position:0% +okay +again think about the problem you face + + align:start position:0% +again think about the problem you face + + + align:start position:0% +again think about the problem you face +when you emerge from the subway in + + align:start position:0% +when you emerge from the subway in + + + align:start position:0% +when you emerge from the subway in +manhattan right like you look around + + align:start position:0% +manhattan right like you look around + + + align:start position:0% +manhattan right like you look around +where am i and which way am i heading + + align:start position:0% +where am i and which way am i heading + + + align:start position:0% +where am i and which way am i heading +that's what you need retrospective + + align:start position:0% +that's what you need retrospective + + + align:start position:0% +that's what you need retrospective +cortex for + + align:start position:0% +cortex for + + + align:start position:0% +cortex for +okay + + align:start position:0% + + + + align:start position:0% + +all right how about this tos thing i'll + + align:start position:0% +all right how about this tos thing i'll + + + align:start position:0% +all right how about this tos thing i'll +give you there's lots of studies of it + + align:start position:0% +give you there's lots of studies of it + + + align:start position:0% +give you there's lots of studies of it +i'll give you just one little offering + + align:start position:0% +i'll give you just one little offering + + + align:start position:0% +i'll give you just one little offering +okay so + + align:start position:0% +okay so + + + align:start position:0% +okay so +this is a + + align:start position:0% +this is a + + + align:start position:0% +this is a +causal investigation because as we + + align:start position:0% +causal investigation because as we + + + align:start position:0% +causal investigation because as we +discussed tos is out on the lateral + + align:start position:0% +discussed tos is out on the lateral + + + align:start position:0% +discussed tos is out on the lateral +surface so we can zap it and so of + + align:start position:0% +surface so we can zap it and so of + + + align:start position:0% +surface so we can zap it and so of +course we do + + align:start position:0% +course we do + + + align:start position:0% +course we do +and so in this study + + align:start position:0% +and so in this study + + + align:start position:0% +and so in this study +we were asking + + align:start position:0% +we were asking + + + align:start position:0% +we were asking +whether tos is involved in perceiving + + align:start position:0% +whether tos is involved in perceiving + + + align:start position:0% +whether tos is involved in perceiving +the structure of space around you + + align:start position:0% +the structure of space around you + + + align:start position:0% +the structure of space around you +so we took scenes like this from cad + + align:start position:0% +so we took scenes like this from cad + + + align:start position:0% +so we took scenes like this from cad +programs and we just varied them + + align:start position:0% +programs and we just varied them + + + align:start position:0% +programs and we just varied them +slightly so for example the position of + + align:start position:0% +slightly so for example the position of + + + align:start position:0% +slightly so for example the position of +this wall moves around + + align:start position:0% +this wall moves around + + + align:start position:0% +this wall moves around +the aspect ratio the height of the + + align:start position:0% +the aspect ratio the height of the + + + align:start position:0% +the aspect ratio the height of the +ceiling moves around and we make this + + align:start position:0% +ceiling moves around and we make this + + + align:start position:0% +ceiling moves around and we make this +subtle morph space of different versions + + align:start position:0% +subtle morph space of different versions + + + align:start position:0% +subtle morph space of different versions +of this image + + align:start position:0% +of this image + + + align:start position:0% +of this image +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and then for control condition we do the + + align:start position:0% +and then for control condition we do the + + + align:start position:0% +and then for control condition we do the +same with faces we morph between this + + align:start position:0% +same with faces we morph between this + + + align:start position:0% +same with faces we morph between this +guy and that guy who make a whole + + align:start position:0% +guy and that guy who make a whole + + + align:start position:0% +guy and that guy who make a whole +spectrum in between + + align:start position:0% +spectrum in between + + + align:start position:0% +spectrum in between +and then in the task what we do is + + align:start position:0% +and then in the task what we do is + + + align:start position:0% +and then in the task what we do is +here's one trial + + align:start position:0% +here's one trial + + + align:start position:0% +here's one trial +one of the scenes or faces comes on + + align:start position:0% +one of the scenes or faces comes on + + + align:start position:0% +one of the scenes or faces comes on +uh briefly and then shortly thereafter + + align:start position:0% +uh briefly and then shortly thereafter + + + align:start position:0% +uh briefly and then shortly thereafter +you get a choice of two and you have to + + align:start position:0% +you get a choice of two and you have to + + + align:start position:0% +you get a choice of two and you have to +say which of these matches that one + + align:start position:0% +say which of these matches that one + + + align:start position:0% +say which of these matches that one +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and then what we do is we zap people + + align:start position:0% +and then what we do is we zap people + + + align:start position:0% +and then what we do is we zap people +right after we present this stimulus + + align:start position:0% +right after we present this stimulus + + + align:start position:0% +right after we present this stimulus +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and so the idea is this is as close as + + align:start position:0% +and so the idea is this is as close as + + + align:start position:0% +and so the idea is this is as close as +we can get to a pretty pure perceptual + + align:start position:0% +we can get to a pretty pure perceptual + + + align:start position:0% +we can get to a pretty pure perceptual +task how well can you see the shape of + + align:start position:0% +task how well can you see the shape of + + + align:start position:0% +task how well can you see the shape of +that environment or the shape of that + + align:start position:0% +that environment or the shape of that + + + align:start position:0% +that environment or the shape of that +face + + align:start position:0% +face + + + align:start position:0% +face +okay you don't have to remember it for + + align:start position:0% +okay you don't have to remember it for + + + align:start position:0% +okay you don't have to remember it for +more than a few hundred milliseconds so + + align:start position:0% +more than a few hundred milliseconds so + + + align:start position:0% +more than a few hundred milliseconds so +it's really more of a perception task + + align:start position:0% +it's really more of a perception task + + + align:start position:0% +it's really more of a perception task +than a memory task okay and what we + + align:start position:0% +than a memory task okay and what we + + + align:start position:0% +than a memory task okay and what we +measure is we actually + + align:start position:0% +measure is we actually + + + align:start position:0% +measure is we actually +um + + align:start position:0% +um + + + align:start position:0% +um +muck with how different these two images + + align:start position:0% +muck with how different these two images + + + align:start position:0% +muck with how different these two images +are in each trial and measure how far + + align:start position:0% +are in each trial and measure how far + + + align:start position:0% +are in each trial and measure how far +apart they have to be in morph space for + + align:start position:0% +apart they have to be in morph space for + + + align:start position:0% +apart they have to be in morph space for +you to be about 75 percent correct okay + + align:start position:0% +you to be about 75 percent correct okay + + + align:start position:0% +you to be about 75 percent correct okay +that's a kind of + + align:start position:0% +that's a kind of + + + align:start position:0% +that's a kind of +standard psychophysical measure the + + align:start position:0% +standard psychophysical measure the + + + align:start position:0% +standard psychophysical measure the +details don't matter but our dependent + + align:start position:0% +details don't matter but our dependent + + + align:start position:0% +details don't matter but our dependent +measure is how different did the stimuli + + align:start position:0% +measure is how different did the stimuli + + + align:start position:0% +measure is how different did the stimuli +have to be for you to discriminate them + + align:start position:0% +have to be for you to discriminate them + + + align:start position:0% +have to be for you to discriminate them +as a function of what do you get whether + + align:start position:0% +as a function of what do you get whether + + + align:start position:0% +as a function of what do you get whether +you're getting zapped in tos or not + + align:start position:0% +you're getting zapped in tos or not + + + align:start position:0% +you're getting zapped in tos or not +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and so here are the data + + align:start position:0% +and so here are the data + + + align:start position:0% +and so here are the data +so let's take the case where you're + + align:start position:0% +so let's take the case where you're + + + align:start position:0% +so let's take the case where you're +doing the scene task here + + align:start position:0% +doing the scene task here + + + align:start position:0% +doing the scene task here +what this threshold is is again how + + align:start position:0% +what this threshold is is again how + + + align:start position:0% +what this threshold is is again how +different the stimuli need to be for you + + align:start position:0% +different the stimuli need to be for you + + + align:start position:0% +different the stimuli need to be for you +to discriminate them so the higher the + + align:start position:0% +to discriminate them so the higher the + + + align:start position:0% +to discriminate them so the higher the +bar + + align:start position:0% +bar + + + align:start position:0% +bar +the worse performance okay they have to + + align:start position:0% +the worse performance okay they have to + + + align:start position:0% +the worse performance okay they have to +be really different or you can't tell + + align:start position:0% +be really different or you can't tell + + + align:start position:0% +be really different or you can't tell +them apart + + align:start position:0% +them apart + + + align:start position:0% +them apart +and so what you see is + + align:start position:0% +and so what you see is + + + align:start position:0% +and so what you see is +when you zap + + align:start position:0% +when you zap + + + align:start position:0% +when you zap +opa + + align:start position:0% +opa + + + align:start position:0% +opa +that lateral scene selective region + + align:start position:0% +that lateral scene selective region + + + align:start position:0% +that lateral scene selective region +discrimination + + align:start position:0% +discrimination + + + align:start position:0% +discrimination +threshold goes up a bit that means you + + align:start position:0% +threshold goes up a bit that means you + + + align:start position:0% +threshold goes up a bit that means you +get worse at the discrimination the + + align:start position:0% +get worse at the discrimination the + + + align:start position:0% +get worse at the discrimination the +stimuli need to be more different + + align:start position:0% +stimuli need to be more different + + + align:start position:0% +stimuli need to be more different +compared to zapping the top of your head + + align:start position:0% +compared to zapping the top of your head + + + align:start position:0% +compared to zapping the top of your head +okay remember you always want to control + + align:start position:0% +okay remember you always want to control + + + align:start position:0% +okay remember you always want to control +condition and there's no perfect control + + align:start position:0% +condition and there's no perfect control + + + align:start position:0% +condition and there's no perfect control +condition because it feels differently + + align:start position:0% +condition because it feels differently + + + align:start position:0% +condition because it feels differently +to be zapped in different places but + + align:start position:0% +to be zapped in different places but + + + align:start position:0% +to be zapped in different places but +getting zapped up here is a + + align:start position:0% +getting zapped up here is a + + + align:start position:0% +getting zapped up here is a +you know + + align:start position:0% +you know + + + align:start position:0% +you know +better than nothing control + + align:start position:0% +better than nothing control + + + align:start position:0% +better than nothing control +and then here's the occipital face area + + align:start position:0% +and then here's the occipital face area + + + align:start position:0% +and then here's the occipital face area +that's the lateral face region we talked + + align:start position:0% +that's the lateral face region we talked + + + align:start position:0% +that's the lateral face region we talked +about before when i showed you another + + align:start position:0% +about before when i showed you another + + + align:start position:0% +about before when i showed you another +tms study basically whenever there's + + align:start position:0% +tms study basically whenever there's + + + align:start position:0% +tms study basically whenever there's +anything lateral we zap it because we + + align:start position:0% +anything lateral we zap it because we + + + align:start position:0% +anything lateral we zap it because we +can't + + align:start position:0% +can't + + + align:start position:0% +can't +and see it's not affected here + + align:start position:0% +and see it's not affected here + + + align:start position:0% +and see it's not affected here +zapping the occipital face area does not + + align:start position:0% +zapping the occipital face area does not + + + align:start position:0% +zapping the occipital face area does not +mess up your ability to discriminate the + + align:start position:0% +mess up your ability to discriminate the + + + align:start position:0% +mess up your ability to discriminate the +scenes + + align:start position:0% +scenes + + + align:start position:0% +scenes +however + + align:start position:0% +however + + + align:start position:0% +however +in the face task we see the opposite + + align:start position:0% +in the face task we see the opposite + + + align:start position:0% +in the face task we see the opposite +pattern for the face task + + align:start position:0% +pattern for the face task + + + align:start position:0% +pattern for the face task +zapping + + align:start position:0% +zapping + + + align:start position:0% +zapping +the occipital place area doesn't do + + align:start position:0% +the occipital place area doesn't do + + + align:start position:0% +the occipital place area doesn't do +anything compared to zapping the top of + + align:start position:0% +anything compared to zapping the top of + + + align:start position:0% +anything compared to zapping the top of +your head but zapping the face area does + + align:start position:0% +your head but zapping the face area does + + + align:start position:0% +your head but zapping the face area does +this is a double dissociation + + align:start position:0% +this is a double dissociation + + + align:start position:0% +this is a double dissociation +okay if we just had + + align:start position:0% +okay if we just had + + + align:start position:0% +okay if we just had +if we just had the scene task and be + + align:start position:0% +if we just had the scene task and be + + + align:start position:0% +if we just had the scene task and be +like yeah maybe + + align:start position:0% +like yeah maybe + + + align:start position:0% +like yeah maybe +who knows + + align:start position:0% +who knows + + + align:start position:0% +who knows +maybe + + align:start position:0% +maybe + + + align:start position:0% +maybe +maybe who knows why but you know it's + + align:start position:0% +maybe who knows why but you know it's + + + align:start position:0% +maybe who knows why but you know it's +not very strong but when you have these + + align:start position:0% +not very strong but when you have these + + + align:start position:0% +not very strong but when you have these +opposite things then we really have much + + align:start position:0% +opposite things then we really have much + + + align:start position:0% +opposite things then we really have much +more + + align:start position:0% +more + + + align:start position:0% +more +um strong evidence that these two + + align:start position:0% +um strong evidence that these two + + + align:start position:0% +um strong evidence that these two +regions have different functions from + + align:start position:0% +regions have different functions from + + + align:start position:0% +regions have different functions from +each other + + align:start position:0% +each other + + + align:start position:0% +each other +okay everybody get that this is a double + + align:start position:0% +okay everybody get that this is a double + + + align:start position:0% +okay everybody get that this is a double +dissociation in the same sense of when + + align:start position:0% +dissociation in the same sense of when + + + align:start position:0% +dissociation in the same sense of when +you have one patient with damage in one + + align:start position:0% +you have one patient with damage in one + + + align:start position:0% +you have one patient with damage in one +location and another patient with damage + + align:start position:0% +location and another patient with damage + + + align:start position:0% +location and another patient with damage +in another location and they have + + align:start position:0% +in another location and they have + + + align:start position:0% +in another location and they have +opposite patterns of deficit then we're + + align:start position:0% +opposite patterns of deficit then we're + + + align:start position:0% +opposite patterns of deficit then we're +really kind of in business then we can + + align:start position:0% +really kind of in business then we can + + + align:start position:0% +really kind of in business then we can +draw strong inferences + + align:start position:0% +draw strong inferences + + + align:start position:0% +draw strong inferences +okay + + align:start position:0% +okay + + + align:start position:0% +okay +all right so we just said all of that + + align:start position:0% +all right so we just said all of that + + + align:start position:0% +all right so we just said all of that +okay so that's just a little snippet + + align:start position:0% +okay so that's just a little snippet + + + align:start position:0% +okay so that's just a little snippet +these and other data suggest that that + + align:start position:0% +these and other data suggest that that + + + align:start position:0% +these and other data suggest that that +region + + align:start position:0% +region + + + align:start position:0% +region +um is strongly active when you look at + + align:start position:0% +um is strongly active when you look at + + + align:start position:0% +um is strongly active when you look at +scenes uh and it seems to be involved in + + align:start position:0% +scenes uh and it seems to be involved in + + + align:start position:0% +scenes uh and it seems to be involved in +something like perceiving you know + + align:start position:0% +something like perceiving you know + + + align:start position:0% +something like perceiving you know +directly online perceiving the structure + + align:start position:0% +directly online perceiving the structure + + + align:start position:0% +directly online perceiving the structure +of the space in front of you + + align:start position:0% +of the space in front of you + + + align:start position:0% +of the space in front of you +okay + + align:start position:0% + + + + align:start position:0% + +all right um so + + align:start position:0% +all right um so + + + align:start position:0% +all right um so +um + + align:start position:0% +um + + + align:start position:0% +um +yeah we already did retrosplenial cortex + + align:start position:0% +yeah we already did retrosplenial cortex + + + align:start position:0% +yeah we already did retrosplenial cortex +and next time we'll talk about the + + align:start position:0% +and next time we'll talk about the + + + align:start position:0% +and next time we'll talk about the +hippocampus in there and its role + + align:start position:0% +hippocampus in there and its role + + + align:start position:0% +hippocampus in there and its role +in the whole navigation thing + + align:start position:0% +in the whole navigation thing + + + align:start position:0% +in the whole navigation thing +now since i + + align:start position:0% +now since i + + + align:start position:0% +now since i +have + + align:start position:0% + + + + align:start position:0% + +ended early + + align:start position:0% +ended early + + + align:start position:0% +ended early +a rare event i actually put together a + + align:start position:0% +a rare event i actually put together a + + + align:start position:0% +a rare event i actually put together a +whole other piece of this lecture and i + + align:start position:0% +whole other piece of this lecture and i + + + align:start position:0% +whole other piece of this lecture and i +thought no don't always have a part you + + align:start position:0% +thought no don't always have a part you + + + align:start position:0% +thought no don't always have a part you +don't get to + + align:start position:0% +don't get to + + + align:start position:0% +don't get to +but then it turns out + + align:start position:0% +but then it turns out + + + align:start position:0% +but then it turns out +maybe we do get to it + + align:start position:0% +maybe we do get to it + + + align:start position:0% +maybe we do get to it +um + + align:start position:0% +um + + + align:start position:0% +um +okay we're gonna we're gonna go over + + align:start position:0% +okay we're gonna we're gonna go over + + + align:start position:0% +okay we're gonna we're gonna go over +this more later but we're going to start + + align:start position:0% +this more later but we're going to start + + + align:start position:0% +this more later but we're going to start +with this + + align:start position:0% +with this + + + align:start position:0% +with this +business right here so anybody have + + align:start position:0% +business right here so anybody have + + + align:start position:0% +business right here so anybody have +questions about the stuff so far + + align:start position:0% +questions about the stuff so far + + + align:start position:0% +questions about the stuff so far +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so i've spent a lot of time talking + + align:start position:0% +so i've spent a lot of time talking + + + align:start position:0% +so i've spent a lot of time talking +about multiple voxel pattern analysis + + align:start position:0% +about multiple voxel pattern analysis + + + align:start position:0% +about multiple voxel pattern analysis +because it's the only method i've + + align:start position:0% +because it's the only method i've + + + align:start position:0% +because it's the only method i've +mentioned so far that enables us to go + + align:start position:0% +mentioned so far that enables us to go + + + align:start position:0% +mentioned so far that enables us to go +beyond the business of saying + + align:start position:0% +beyond the business of saying + + + align:start position:0% +beyond the business of saying +how strongly do the neurons fire in this + + align:start position:0% +how strongly do the neurons fire in this + + + align:start position:0% +how strongly do the neurons fire in this +region to the more interesting question + + align:start position:0% +region to the more interesting question + + + align:start position:0% +region to the more interesting question +of what information is contained in this + + align:start position:0% +of what information is contained in this + + + align:start position:0% +of what information is contained in this +region okay + + align:start position:0% +region okay + + + align:start position:0% +region okay +but i also ended the last lecture with + + align:start position:0% +but i also ended the last lecture with + + + align:start position:0% +but i also ended the last lecture with +this kind of depressive note + + align:start position:0% +this kind of depressive note + + + align:start position:0% +this kind of depressive note +that you can't see much with mvpa + + align:start position:0% +that you can't see much with mvpa + + + align:start position:0% +that you can't see much with mvpa +applied to face patches + + align:start position:0% +applied to face patches + + + align:start position:0% +applied to face patches +even when we know there's information in + + align:start position:0% +even when we know there's information in + + + align:start position:0% +even when we know there's information in +there with electrophysiology data + + align:start position:0% +there with electrophysiology data + + + align:start position:0% +there with electrophysiology data +remember i showed you that monkey study + + align:start position:0% +remember i showed you that monkey study + + + align:start position:0% +remember i showed you that monkey study +where they tried mvpa in the face + + align:start position:0% +where they tried mvpa in the face + + + align:start position:0% +where they tried mvpa in the face +patches and monkeys and they couldn't + + align:start position:0% +patches and monkeys and they couldn't + + + align:start position:0% +patches and monkeys and they couldn't +kind of read out a damn thing + + align:start position:0% +kind of read out a damn thing + + + align:start position:0% +kind of read out a damn thing +and then they try mvpa on individual + + align:start position:0% +and then they try mvpa on individual + + + align:start position:0% +and then they try mvpa on individual +neural responses of the same region and + + align:start position:0% +neural responses of the same region and + + + align:start position:0% +neural responses of the same region and +they can read out all kinds of + + align:start position:0% +they can read out all kinds of + + + align:start position:0% +they can read out all kinds of +information and that tells you the + + align:start position:0% +information and that tells you the + + + align:start position:0% +information and that tells you the +information is there and we just can't + + align:start position:0% +information is there and we just can't + + + align:start position:0% +information is there and we just can't +always see it with mvpa now today you've + + align:start position:0% +always see it with mvpa now today you've + + + align:start position:0% +always see it with mvpa now today you've +seen cases where you can see stuff with + + align:start position:0% +seen cases where you can see stuff with + + + align:start position:0% +seen cases where you can see stuff with +mvpa in the scene region so sometimes it + + align:start position:0% +mvpa in the scene region so sometimes it + + + align:start position:0% +mvpa in the scene region so sometimes it +works sometimes it doesn't + + align:start position:0% +works sometimes it doesn't + + + align:start position:0% +works sometimes it doesn't +and when it doesn't work we're left in + + align:start position:0% +and when it doesn't work we're left in + + + align:start position:0% +and when it doesn't work we're left in +this unsatisfying situation that we + + align:start position:0% +this unsatisfying situation that we + + + align:start position:0% +this unsatisfying situation that we +don't know if the information isn't + + align:start position:0% +don't know if the information isn't + + + align:start position:0% +don't know if the information isn't +there + + align:start position:0% +there + + + align:start position:0% +there +or if the neurons are just so scrambled + + align:start position:0% +or if the neurons are just so scrambled + + + align:start position:0% +or if the neurons are just so scrambled +together + + align:start position:0% +together + + + align:start position:0% +together +that we just don't we can't see the um + + align:start position:0% +that we just don't we can't see the um + + + align:start position:0% +that we just don't we can't see the um +see the different patterns + + align:start position:0% +see the different patterns + + + align:start position:0% +see the different patterns +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so bottom line we need another method + + align:start position:0% +so bottom line we need another method + + + align:start position:0% +so bottom line we need another method +mvpa is a whole lot better than nothing + + align:start position:0% +mvpa is a whole lot better than nothing + + + align:start position:0% +mvpa is a whole lot better than nothing +but we want to be able to ask is there + + align:start position:0% +but we want to be able to ask is there + + + align:start position:0% +but we want to be able to ask is there +information present in this region + + align:start position:0% +information present in this region + + + align:start position:0% +information present in this region +even when we think the relevant neurons + + align:start position:0% +even when we think the relevant neurons + + + align:start position:0% +even when we think the relevant neurons +are all spatially intermingled + + align:start position:0% +are all spatially intermingled + + + align:start position:0% +are all spatially intermingled +okay so let me just do a little bit of + + align:start position:0% +okay so let me just do a little bit of + + + align:start position:0% +okay so let me just do a little bit of +this and then we'll continue later okay + + align:start position:0% +this and then we'll continue later okay + + + align:start position:0% +this and then we'll continue later okay +so goal we want to this is this new + + align:start position:0% +so goal we want to this is this new + + + align:start position:0% +so goal we want to this is this new +method is called + + align:start position:0% +method is called + + + align:start position:0% +method is called +event related functional mri adaptation + + align:start position:0% +event related functional mri adaptation + + + align:start position:0% +event related functional mri adaptation +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and we use it when we want to know if + + align:start position:0% +and we use it when we want to know if + + + align:start position:0% +and we use it when we want to know if +neural populations in a particular + + align:start position:0% +neural populations in a particular + + + align:start position:0% +neural populations in a particular +region can discriminate between two + + align:start position:0% +region can discriminate between two + + + align:start position:0% +region can discriminate between two +stimuli or two stimulus classes + + align:start position:0% +stimuli or two stimulus classes + + + align:start position:0% +stimuli or two stimulus classes +so for example + + align:start position:0% +so for example + + + align:start position:0% +so for example +do neurons in the ffa distinguish + + align:start position:0% +do neurons in the ffa distinguish + + + align:start position:0% +do neurons in the ffa distinguish +between this image + + align:start position:0% +between this image + + + align:start position:0% +between this image +and that image + + align:start position:0% +and that image + + + align:start position:0% +and that image +okay so if we want to know that + + align:start position:0% +okay so if we want to know that + + + align:start position:0% +okay so if we want to know that +we could measure the functional mri + + align:start position:0% +we could measure the functional mri + + + align:start position:0% +we could measure the functional mri +response in the ffa and find this would + + align:start position:0% +response in the ffa and find this would + + + align:start position:0% +response in the ffa and find this would +be an event related response similar + + align:start position:0% +be an event related response similar + + + align:start position:0% +be an event related response similar +responses to the two + + align:start position:0% +responses to the two + + + align:start position:0% +responses to the two +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and as i just mentioned + + align:start position:0% +and as i just mentioned + + + align:start position:0% +and as i just mentioned +that wouldn't mean that there isn't + + align:start position:0% +that wouldn't mean that there isn't + + + align:start position:0% +that wouldn't mean that there isn't +information + + align:start position:0% +information + + + align:start position:0% +information +in the ffa that discriminates that it + + align:start position:0% +in the ffa that discriminates that it + + + align:start position:0% +in the ffa that discriminates that it +just says they have the same mean + + align:start position:0% +just says they have the same mean + + + align:start position:0% +just says they have the same mean +response everybody get that + + align:start position:0% +response everybody get that + + + align:start position:0% +response everybody get that +okay + + align:start position:0% +okay + + + align:start position:0% +okay +now + + align:start position:0% +now + + + align:start position:0% +now +if we zoom in and think about what might + + align:start position:0% +if we zoom in and think about what might + + + align:start position:0% +if we zoom in and think about what might +neurons be doing + + align:start position:0% +neurons be doing + + + align:start position:0% +neurons be doing +it's still possible even with the same + + align:start position:0% +it's still possible even with the same + + + align:start position:0% +it's still possible even with the same +mean response that neurons could be + + align:start position:0% +mean response that neurons could be + + + align:start position:0% +mean response that neurons could be +organized like this with some of them + + align:start position:0% +organized like this with some of them + + + align:start position:0% +organized like this with some of them +responding only to this image and some + + align:start position:0% +responding only to this image and some + + + align:start position:0% +responding only to this image and some +of them responding only to that image + + align:start position:0% +of them responding only to that image + + + align:start position:0% +of them responding only to that image +but it's also possible that all of the + + align:start position:0% +but it's also possible that all of the + + + align:start position:0% +but it's also possible that all of the +neurons respond equally to both + + align:start position:0% +neurons respond equally to both + + + align:start position:0% +neurons respond equally to both +and we kind of desperately need to know + + align:start position:0% +and we kind of desperately need to know + + + align:start position:0% +and we kind of desperately need to know +i mean not in this case this is a toy + + align:start position:0% +i mean not in this case this is a toy + + + align:start position:0% +i mean not in this case this is a toy +example obviously but we often when + + align:start position:0% +example obviously but we often when + + + align:start position:0% +example obviously but we often when +we're trying to understand a region of + + align:start position:0% +we're trying to understand a region of + + + align:start position:0% +we're trying to understand a region of +the brain we need to know which + + align:start position:0% +the brain we need to know which + + + align:start position:0% +the brain we need to know which +situation we're in + + align:start position:0% +situation we're in + + + align:start position:0% +situation we're in +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so + + align:start position:0% +so + + + align:start position:0% +so +that neural population can discriminate + + align:start position:0% +that neural population can discriminate + + + align:start position:0% +that neural population can discriminate +these two and that one can't + + align:start position:0% +these two and that one can't + + + align:start position:0% +these two and that one can't +okay + + align:start position:0% +okay + + + align:start position:0% +okay +how are we going to tell which is true + + align:start position:0% +how are we going to tell which is true + + + align:start position:0% +how are we going to tell which is true +well we talked before about multiple + + align:start position:0% +well we talked before about multiple + + + align:start position:0% +well we talked before about multiple +voxel pattern analysis but as i just + + align:start position:0% +voxel pattern analysis but as i just + + + align:start position:0% +voxel pattern analysis but as i just +said it only works + + align:start position:0% +said it only works + + + align:start position:0% +said it only works +when the neurons are spatially clustered + + align:start position:0% +when the neurons are spatially clustered + + + align:start position:0% +when the neurons are spatially clustered +on the scale of voxels + + align:start position:0% +on the scale of voxels + + + align:start position:0% +on the scale of voxels +okay so + + align:start position:0% +okay so + + + align:start position:0% +okay so +imagine you have these situations here + + align:start position:0% +imagine you have these situations here + + + align:start position:0% +imagine you have these situations here +this is getting more and more of a toy + + align:start position:0% +this is getting more and more of a toy + + + align:start position:0% +this is getting more and more of a toy +example but just to give you the idea + + align:start position:0% +example but just to give you the idea + + + align:start position:0% +example but just to give you the idea +suppose where those neural populations + + align:start position:0% +suppose where those neural populations + + + align:start position:0% +suppose where those neural populations +land with respect to voxels is like this + + align:start position:0% +land with respect to voxels is like this + + + align:start position:0% +land with respect to voxels is like this +so if each of these is a voxel in the + + align:start position:0% +so if each of these is a voxel in the + + + align:start position:0% +so if each of these is a voxel in the +brain a little say two by two by three + + align:start position:0% +brain a little say two by two by three + + + align:start position:0% +brain a little say two by two by three +millimeter chunk of brain that we're + + align:start position:0% +millimeter chunk of brain that we're + + + align:start position:0% +millimeter chunk of brain that we're +getting an mri signal from + + align:start position:0% +getting an mri signal from + + + align:start position:0% +getting an mri signal from +if you have the different neural + + align:start position:0% +if you have the different neural + + + align:start position:0% +if you have the different neural +populations spatially segregated enough + + align:start position:0% +populations spatially segregated enough + + + align:start position:0% +populations spatially segregated enough +that they mostly land in different + + align:start position:0% +that they mostly land in different + + + align:start position:0% +that they mostly land in different +voxels + + align:start position:0% +voxels + + + align:start position:0% +voxels +then mvpa might work here + + align:start position:0% +then mvpa might work here + + + align:start position:0% +then mvpa might work here +is that intuitive do you guys all see + + align:start position:0% +is that intuitive do you guys all see + + + align:start position:0% +is that intuitive do you guys all see +that then we get a different pattern in + + align:start position:0% +that then we get a different pattern in + + + align:start position:0% +that then we get a different pattern in +these voxels + + align:start position:0% +these voxels + + + align:start position:0% +these voxels +for looking at those two different + + align:start position:0% +for looking at those two different + + + align:start position:0% +for looking at those two different +images + + align:start position:0% +images + + + align:start position:0% +images +but even if we have + + align:start position:0% +but even if we have + + + align:start position:0% +but even if we have +the situation here which is kind of + + align:start position:0% +the situation here which is kind of + + + align:start position:0% +the situation here which is kind of +informationally the same if they're + + align:start position:0% +informationally the same if they're + + + align:start position:0% +informationally the same if they're +spatially scrambled + + align:start position:0% +spatially scrambled + + + align:start position:0% +spatially scrambled +so that they're in roughly equal + + align:start position:0% +so that they're in roughly equal + + + align:start position:0% +so that they're in roughly equal +proportion in each voxel mvpa won't work + + align:start position:0% +proportion in each voxel mvpa won't work + + + align:start position:0% +proportion in each voxel mvpa won't work +does that make sense + + align:start position:0% +does that make sense + + + align:start position:0% +does that make sense +and so that's when we need this other + + align:start position:0% +and so that's when we need this other + + + align:start position:0% +and so that's when we need this other +method called functional memory + + align:start position:0% +method called functional memory + + + align:start position:0% +method called functional memory +adaptation + + align:start position:0% +adaptation + + + align:start position:0% +adaptation +makes sense + + align:start position:0% +makes sense + + + align:start position:0% +makes sense +okay i'm going to go one minute over + + align:start position:0% +okay i'm going to go one minute over + + + align:start position:0% +okay i'm going to go one minute over +probably + + align:start position:0% +probably + + + align:start position:0% +probably +okay so the point of functional mri + + align:start position:0% +okay so the point of functional mri + + + align:start position:0% +okay so the point of functional mri +adaptation is it can work even when + + align:start position:0% +adaptation is it can work even when + + + align:start position:0% +adaptation is it can work even when +there's no spatial clustering of the + + align:start position:0% +there's no spatial clustering of the + + + align:start position:0% +there's no spatial clustering of the +relevant neural populations on the scale + + align:start position:0% +relevant neural populations on the scale + + + align:start position:0% +relevant neural populations on the scale +of voxels so let me go through it + + align:start position:0% +of voxels so let me go through it + + + align:start position:0% +of voxels so let me go through it +quickly and we'll come back to it later + + align:start position:0% +quickly and we'll come back to it later + + + align:start position:0% +quickly and we'll come back to it later +so here's how it goes the basic idea is + + align:start position:0% +so here's how it goes the basic idea is + + + align:start position:0% +so here's how it goes the basic idea is +any measure that's sensitive to the + + align:start position:0% +any measure that's sensitive to the + + + align:start position:0% +any measure that's sensitive to the +sameness versus difference between two + + align:start position:0% +sameness versus difference between two + + + align:start position:0% +sameness versus difference between two +stimuli + + align:start position:0% +stimuli + + + align:start position:0% +stimuli +can reveal what that system takes to be + + align:start position:0% +can reveal what that system takes to be + + + align:start position:0% +can reveal what that system takes to be +same or different + + align:start position:0% +same or different + + + align:start position:0% +same or different +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so for example if a brain region + + align:start position:0% +so for example if a brain region + + + align:start position:0% +so for example if a brain region +discriminates between two similar + + align:start position:0% +discriminates between two similar + + + align:start position:0% +discriminates between two similar +stimuli like these + + align:start position:0% +stimuli like these + + + align:start position:0% +stimuli like these +then + + align:start position:0% +then + + + align:start position:0% +then +if we measure the functional mri + + align:start position:0% +if we measure the functional mri + + + align:start position:0% +if we measure the functional mri +response in that region to same versus + + align:start position:0% +response in that region to same versus + + + align:start position:0% +response in that region to same versus +different trials + + align:start position:0% +different trials + + + align:start position:0% +different trials +okay so this would be a different trial + + align:start position:0% +okay so this would be a different trial + + + align:start position:0% +okay so this would be a different trial +you present + + align:start position:0% +you present + + + align:start position:0% +you present +trump and then the chimp back to back + + align:start position:0% +trump and then the chimp back to back + + + align:start position:0% +trump and then the chimp back to back +that's one trial + + align:start position:0% +that's one trial + + + align:start position:0% +that's one trial +compared to a same trial chimp and then + + align:start position:0% +compared to a same trial chimp and then + + + align:start position:0% +compared to a same trial chimp and then +chimp + + align:start position:0% +chimp + + + align:start position:0% +chimp +and of course we counter balance + + align:start position:0% +and of course we counter balance + + + align:start position:0% +and of course we counter balance +everything so we also do chimp and then + + align:start position:0% +everything so we also do chimp and then + + + align:start position:0% +everything so we also do chimp and then +trump in another different case and then + + align:start position:0% +trump in another different case and then + + + align:start position:0% +trump in another different case and then +trump and then trump in another same + + align:start position:0% +trump and then trump in another same + + + align:start position:0% +trump and then trump in another same +case right + + align:start position:0% +case right + + + align:start position:0% +case right +if we find + + align:start position:0% +if we find + + + align:start position:0% +if we find +that the neural response is higher when + + align:start position:0% +that the neural response is higher when + + + align:start position:0% +that the neural response is higher when +the two stimuli are different than when + + align:start position:0% +the two stimuli are different than when + + + align:start position:0% +the two stimuli are different than when +they're the same + + align:start position:0% +they're the same + + + align:start position:0% +they're the same +then + + align:start position:0% +then + + + align:start position:0% +then +we know that that region has neurons + + align:start position:0% +we know that that region has neurons + + + align:start position:0% +we know that that region has neurons +that respond differentially to the two + + align:start position:0% +that respond differentially to the two + + + align:start position:0% +that respond differentially to the two +okay so remember we started with a case + + align:start position:0% +okay so remember we started with a case + + + align:start position:0% +okay so remember we started with a case +where the mean response is the same + + align:start position:0% +where the mean response is the same + + + align:start position:0% +where the mean response is the same +to this image in this image if you just + + align:start position:0% +to this image in this image if you just + + + align:start position:0% +to this image in this image if you just +measure them along + + align:start position:0% +measure them along + + + align:start position:0% +measure them along +but now we want to know are + + align:start position:0% +but now we want to know are + + + align:start position:0% +but now we want to know are +do we really have neurons that respond + + align:start position:0% +do we really have neurons that respond + + + align:start position:0% +do we really have neurons that respond +differentially so we're using the fact + + align:start position:0% +differentially so we're using the fact + + + align:start position:0% +differentially so we're using the fact +that neurons are like people and muscles + + align:start position:0% +that neurons are like people and muscles + + + align:start position:0% +that neurons are like people and muscles +if you keep doing the same thing to them + + align:start position:0% +if you keep doing the same thing to them + + + align:start position:0% +if you keep doing the same thing to them +they get bored + + align:start position:0% +they get bored + + + align:start position:0% +they get bored +been there done that okay + + align:start position:0% +been there done that okay + + + align:start position:0% +been there done that okay +so you present this back to back you get + + align:start position:0% +so you present this back to back you get + + + align:start position:0% +so you present this back to back you get +a lower response than if you present + + align:start position:0% +a lower response than if you present + + + align:start position:0% +a lower response than if you present +this and then this + + align:start position:0% +this and then this + + + align:start position:0% +this and then this +okay that's called functional mri + + align:start position:0% +okay that's called functional mri + + + align:start position:0% +okay that's called functional mri +adaptation it's like that waterfall mta + + align:start position:0% +adaptation it's like that waterfall mta + + + align:start position:0% +adaptation it's like that waterfall mta +adaptation we talked about before but + + align:start position:0% +adaptation we talked about before but + + + align:start position:0% +adaptation we talked about before but +just crammed into a fine time scale + + align:start position:0% +just crammed into a fine time scale + + + align:start position:0% +just crammed into a fine time scale +okay and so then if you do that you can + + align:start position:0% +okay and so then if you do that you can + + + align:start position:0% +okay and so then if you do that you can +ask what a region thinks is the same + + align:start position:0% +ask what a region thinks is the same + + + align:start position:0% +ask what a region thinks is the same +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so then we could ask okay what about + + align:start position:0% +so then we could ask okay what about + + + align:start position:0% +so then we could ask okay what about +these two images + + align:start position:0% +these two images + + + align:start position:0% +these two images +does it think those are the same + + align:start position:0% +does it think those are the same + + + align:start position:0% +does it think those are the same +and if we find a response like that what + + align:start position:0% +and if we find a response like that what + + + align:start position:0% +and if we find a response like that what +have we learned so if these two respond + + align:start position:0% +have we learned so if these two respond + + + align:start position:0% +have we learned so if these two respond +like that what have we learned + + align:start position:0% +like that what have we learned + + + align:start position:0% +like that what have we learned +about a region that shows this is all + + align:start position:0% +about a region that shows this is all + + + align:start position:0% +about a region that shows this is all +fake data obviously but if we saw that + + align:start position:0% +fake data obviously but if we saw that + + + align:start position:0% +fake data obviously but if we saw that +what have we learned + + align:start position:0% +what have we learned + + + align:start position:0% +what have we learned +and then i'll let you go + + align:start position:0% +and then i'll let you go + + + align:start position:0% +and then i'll let you go +as soon as i get a nice answer to this + + align:start position:0% + + + + align:start position:0% + +um so if it's the same between two + + align:start position:0% +um so if it's the same between two + + + align:start position:0% +um so if it's the same between two +pictures of the same stimuli that means + + align:start position:0% +pictures of the same stimuli that means + + + align:start position:0% +pictures of the same stimuli that means +that it's activated like it can + + align:start position:0% +that it's activated like it can + + + align:start position:0% +that it's activated like it can +discriminate but if it were um + + align:start position:0% +discriminate but if it were um + + + align:start position:0% +discriminate but if it were um +if the yellow line had the same degree + + align:start position:0% +if the yellow line had the same degree + + + align:start position:0% +if the yellow line had the same degree +as the red you would just be reacting to + + align:start position:0% +as the red you would just be reacting to + + + align:start position:0% +as the red you would just be reacting to +different pictures + + align:start position:0% +different pictures + + + align:start position:0% +different pictures +i totally get that it's probably right + + align:start position:0% +i totally get that it's probably right + + + align:start position:0% +i totally get that it's probably right +but totally get it + + align:start position:0% +but totally get it + + + align:start position:0% +but totally get it +key point just because i don't want to + + align:start position:0% +key point just because i don't want to + + + align:start position:0% +key point just because i don't want to +torture you guys and go way over but key + + align:start position:0% +torture you guys and go way over but key + + + align:start position:0% +torture you guys and go way over but key +point is + + align:start position:0% +point is + + + align:start position:0% +point is +it's + + align:start position:0% +it's + + + align:start position:0% +it's +the same response is the lower response + + align:start position:0% +the same response is the lower response + + + align:start position:0% +the same response is the lower response +we tell that with this case when we + + align:start position:0% +we tell that with this case when we + + + align:start position:0% +we tell that with this case when we +actually give it a same one so same is + + align:start position:0% +actually give it a same one so same is + + + align:start position:0% +actually give it a same one so same is +lower than different that's just how + + align:start position:0% +lower than different that's just how + + + align:start position:0% +lower than different that's just how +this method works + + align:start position:0% +this method works + + + align:start position:0% +this method works +then we're basically asking does that + + align:start position:0% +then we're basically asking does that + + + align:start position:0% +then we're basically asking does that +count as the same to this brain region + + align:start position:0% +count as the same to this brain region + + + align:start position:0% +count as the same to this brain region +and we're finding yes it does + + align:start position:0% +and we're finding yes it does + + + align:start position:0% +and we're finding yes it does +that tells us that those neurons are + + align:start position:0% +that tells us that those neurons are + + + align:start position:0% +that tells us that those neurons are +invariant to all kinds of things + + align:start position:0% +invariant to all kinds of things + + + align:start position:0% +invariant to all kinds of things +viewpoint facial expression + + align:start position:0% +viewpoint facial expression + + + align:start position:0% +viewpoint facial expression +you know when he last dyed his hair you + + align:start position:0% +you know when he last dyed his hair you + + + align:start position:0% +you know when he last dyed his hair you +know who the hell knows all these other + + align:start position:0% +know who the hell knows all these other + + + align:start position:0% +know who the hell knows all these other +things right + + align:start position:0% + + + + align:start position:0% + +so we'll talk more about this but the + + align:start position:0% +so we'll talk more about this but the + + + align:start position:0% +so we'll talk more about this but the +idea is now we have another method in + + align:start position:0% +idea is now we have another method in + + + align:start position:0% +idea is now we have another method in +addition to mvpa that can start to tell + + align:start position:0% +addition to mvpa that can start to tell + + + align:start position:0% +addition to mvpa that can start to tell +us what neurons are actually + + align:start position:0% +us what neurons are actually + + + align:start position:0% +us what neurons are actually +discriminating okay sorry to go over + + align:start position:0% + + + + align:start position:0% + +you \ No newline at end of file diff --git a/MuqLI4otMIQ.txt b/MuqLI4otMIQ.txt new file mode 100644 index 0000000000000000000000000000000000000000..c056e1a5314b7c131befdc86250213d370265453 --- /dev/null +++ b/MuqLI4otMIQ.txt @@ -0,0 +1,1531 @@ +align:start position:0% + +we will now work with a geometric random + + align:start position:0% +we will now work with a geometric random + + + align:start position:0% +we will now work with a geometric random +variable and put to use our + + align:start position:0% +variable and put to use our + + + align:start position:0% +variable and put to use our +understanding of conditional pmfs and + + align:start position:0% +understanding of conditional pmfs and + + + align:start position:0% +understanding of conditional pmfs and +conditional expectations remember that a + + align:start position:0% +conditional expectations remember that a + + + align:start position:0% +conditional expectations remember that a +geometric random variable corresponds to + + align:start position:0% +geometric random variable corresponds to + + + align:start position:0% +geometric random variable corresponds to +the number of independent coin tosses + + align:start position:0% +the number of independent coin tosses + + + align:start position:0% +the number of independent coin tosses +until the first head occurs and here P + + align:start position:0% +until the first head occurs and here P + + + align:start position:0% +until the first head occurs and here P +is a parameter that describes the coin + + align:start position:0% +is a parameter that describes the coin + + + align:start position:0% +is a parameter that describes the coin +it is the probability of heads at each + + align:start position:0% +it is the probability of heads at each + + + align:start position:0% +it is the probability of heads at each +coin toss we have already seen the + + align:start position:0% +coin toss we have already seen the + + + align:start position:0% +coin toss we have already seen the +formula for the geometric PMF and the + + align:start position:0% +formula for the geometric PMF and the + + + align:start position:0% +formula for the geometric PMF and the +corresponding plot we will now add one + + align:start position:0% +corresponding plot we will now add one + + + align:start position:0% +corresponding plot we will now add one +very important property which is usually + + align:start position:0% +very important property which is usually + + + align:start position:0% +very important property which is usually +called memorylessness ultimately this + + align:start position:0% +called memorylessness ultimately this + + + align:start position:0% +called memorylessness ultimately this +property has to do with the fact that + + align:start position:0% +property has to do with the fact that + + + align:start position:0% +property has to do with the fact that +independent coin tosses do not have any + + align:start position:0% +independent coin tosses do not have any + + + align:start position:0% +independent coin tosses do not have any +memory past coin tosses do not affect + + align:start position:0% +memory past coin tosses do not affect + + + align:start position:0% +memory past coin tosses do not affect +future coin tosses so consider a coin + + align:start position:0% +future coin tosses so consider a coin + + + align:start position:0% +future coin tosses so consider a coin +tossing experiment with independent + + align:start position:0% +tossing experiment with independent + + + align:start position:0% +tossing experiment with independent +tosses and let X be the number of tosses + + align:start position:0% +tosses and let X be the number of tosses + + + align:start position:0% +tosses and let X be the number of tosses +until the first heads and X is geometric + + align:start position:0% +until the first heads and X is geometric + + + align:start position:0% +until the first heads and X is geometric +with parameter P suppose that you show + + align:start position:0% +with parameter P suppose that you show + + + align:start position:0% +with parameter P suppose that you show +up a little after the experiment has + + align:start position:0% +up a little after the experiment has + + + align:start position:0% +up a little after the experiment has +started and you are told that there were + + align:start position:0% +started and you are told that there were + + + align:start position:0% +started and you are told that there were +so far just 1 coin toss and that this + + align:start position:0% +so far just 1 coin toss and that this + + + align:start position:0% +so far just 1 coin toss and that this +coin toss resulted in tails now you have + + align:start position:0% +coin toss resulted in tails now you have + + + align:start position:0% +coin toss resulted in tails now you have +to take over and carry out the remaining + + align:start position:0% +to take over and carry out the remaining + + + align:start position:0% +to take over and carry out the remaining +tosses until heads are observed what + + align:start position:0% +tosses until heads are observed what + + + align:start position:0% +tosses until heads are observed what +should your model be about the future + + align:start position:0% +should your model be about the future + + + align:start position:0% +should your model be about the future +well you will be making independent coin + + align:start position:0% +well you will be making independent coin + + + align:start position:0% +well you will be making independent coin +tosses until the first heads so the + + align:start position:0% +tosses until the first heads so the + + + align:start position:0% +tosses until the first heads so the +number of such tosses will be a random + + align:start position:0% +number of such tosses will be a random + + + align:start position:0% +number of such tosses will be a random +variable which is geometric with + + align:start position:0% +variable which is geometric with + + + align:start position:0% +variable which is geometric with +parameter P so this duration as far as + + align:start position:0% +parameter P so this duration as far as + + + align:start position:0% +parameter P so this duration as far as +you are concerned is geometric with + + align:start position:0% +you are concerned is geometric with + + + align:start position:0% +you are concerned is geometric with +parameter P therefore the number of + + align:start position:0% +parameter P therefore the number of + + + align:start position:0% +parameter P therefore the number of +remaining coin tosses starting from here + + align:start position:0% +remaining coin tosses starting from here + + + align:start position:0% +remaining coin tosses starting from here +given that the first toss was tails has + + align:start position:0% +given that the first toss was tails has + + + align:start position:0% +given that the first toss was tails has +the same geometric distribution as the + + align:start position:0% +the same geometric distribution as the + + + align:start position:0% +the same geometric distribution as the +original random variable X this is the + + align:start position:0% +original random variable X this is the + + + align:start position:0% +original random variable X this is the +memorylessness property + + align:start position:0% +memorylessness property + + + align:start position:0% +memorylessness property +now since X is the total number of coin + + align:start position:0% +now since X is the total number of coin + + + align:start position:0% +now since X is the total number of coin +tosses and since your coin tosses were + + align:start position:0% +tosses and since your coin tosses were + + + align:start position:0% +tosses and since your coin tosses were +all of them except for the first one the + + align:start position:0% +all of them except for the first one the + + + align:start position:0% +all of them except for the first one the +random variable that you are concerned + + align:start position:0% +random variable that you are concerned + + + align:start position:0% +random variable that you are concerned +with is X minus 1 and so the geometric + + align:start position:0% +with is X minus 1 and so the geometric + + + align:start position:0% +with is X minus 1 and so the geometric +distribution that you are seeing here is + + align:start position:0% +distribution that you are seeing here is + + + align:start position:0% +distribution that you are seeing here is +the conditional distribution of X minus + + align:start position:0% +the conditional distribution of X minus + + + align:start position:0% +the conditional distribution of X minus +1 given that the first toss resulted in + + align:start position:0% +1 given that the first toss resulted in + + + align:start position:0% +1 given that the first toss resulted in +tails which is the same as the event + + align:start position:0% +tails which is the same as the event + + + align:start position:0% +tails which is the same as the event +that X is strictly larger than 1 so the + + align:start position:0% +that X is strictly larger than 1 so the + + + align:start position:0% +that X is strictly larger than 1 so the +statement that we have been making is + + align:start position:0% +statement that we have been making is + + + align:start position:0% +statement that we have been making is +the following in more mathematical + + align:start position:0% +the following in more mathematical + + + align:start position:0% +the following in more mathematical +language that conditioned on X being + + align:start position:0% +language that conditioned on X being + + + align:start position:0% +language that conditioned on X being +larger than 1 the random variable X + + align:start position:0% +larger than 1 the random variable X + + + align:start position:0% +larger than 1 the random variable X +minus 1 which is the remaining number of + + align:start position:0% +minus 1 which is the remaining number of + + + align:start position:0% +minus 1 which is the remaining number of +coin tosses has a geometric distribution + + align:start position:0% +coin tosses has a geometric distribution + + + align:start position:0% +coin tosses has a geometric distribution +with parameter P let us now give a more + + align:start position:0% +with parameter P let us now give a more + + + align:start position:0% +with parameter P let us now give a more +precise mathematical arguments but first + + align:start position:0% +precise mathematical arguments but first + + + align:start position:0% +precise mathematical arguments but first +for a special case let us look at the + + align:start position:0% +for a special case let us look at the + + + align:start position:0% +for a special case let us look at the +conditional probabilities for the random + + align:start position:0% +conditional probabilities for the random + + + align:start position:0% +conditional probabilities for the random +variable X minus 1 and calculate for + + align:start position:0% +variable X minus 1 and calculate for + + + align:start position:0% +variable X minus 1 and calculate for +example the conditional probability that + + align:start position:0% +example the conditional probability that + + + align:start position:0% +example the conditional probability that +X minus 1 is equal to 3 given that X is + + align:start position:0% +X minus 1 is equal to 3 given that X is + + + align:start position:0% +X minus 1 is equal to 3 given that X is +larger than 1 which is the same as + + align:start position:0% +larger than 1 which is the same as + + + align:start position:0% +larger than 1 which is the same as +saying that the first toss resulted in + + align:start position:0% +saying that the first toss resulted in + + + align:start position:0% +saying that the first toss resulted in +tails now the first toss resulted in + + align:start position:0% +tails now the first toss resulted in + + + align:start position:0% +tails now the first toss resulted in +tails this is the probability that you + + align:start position:0% +tails this is the probability that you + + + align:start position:0% +tails this is the probability that you +will need 3 more tosses until you + + align:start position:0% +will need 3 more tosses until you + + + align:start position:0% +will need 3 more tosses until you +observe heads needing three more tosses + + align:start position:0% +observe heads needing three more tosses + + + align:start position:0% +observe heads needing three more tosses +until you observe heads is the event + + align:start position:0% +until you observe heads is the event + + + align:start position:0% +until you observe heads is the event +that you had tails in the second toss + + align:start position:0% +that you had tails in the second toss + + + align:start position:0% +that you had tails in the second toss +tails in the third tours and heads in + + align:start position:0% +tails in the third tours and heads in + + + align:start position:0% +tails in the third tours and heads in +the fourth dose and all that is + + align:start position:0% +the fourth dose and all that is + + + align:start position:0% +the fourth dose and all that is +conditioned on the first toss having + + align:start position:0% +conditioned on the first toss having + + + align:start position:0% +conditioned on the first toss having +resulted in tails + + align:start position:0% +resulted in tails + + + align:start position:0% +resulted in tails +however the different coin tosses are + + align:start position:0% +however the different coin tosses are + + + align:start position:0% +however the different coin tosses are +independent so the conditional + + align:start position:0% +independent so the conditional + + + align:start position:0% +independent so the conditional +probabilities given the event that the + + align:start position:0% +probabilities given the event that the + + + align:start position:0% +probabilities given the event that the +first toss was tails should be the same + + align:start position:0% +first toss was tails should be the same + + + align:start position:0% +first toss was tails should be the same +as the unconditional probabilities + + align:start position:0% +as the unconditional probabilities + + + align:start position:0% +as the unconditional probabilities +first toss does not change our beliefs + + align:start position:0% +first toss does not change our beliefs + + + align:start position:0% +first toss does not change our beliefs +about the probabilities associated with + + align:start position:0% +about the probabilities associated with + + + align:start position:0% +about the probabilities associated with +the remaining tosses now this + + align:start position:0% +the remaining tosses now this + + + align:start position:0% +the remaining tosses now this +unconditional probability is easy to + + align:start position:0% +unconditional probability is easy to + + + align:start position:0% +unconditional probability is easy to +calculate it is 1 minus P squared + + align:start position:0% +calculate it is 1 minus P squared + + + align:start position:0% +calculate it is 1 minus P squared +because we have two tails in a row times + + align:start position:0% +because we have two tails in a row times + + + align:start position:0% +because we have two tails in a row times +P now we observe that this quantity here + + align:start position:0% +P now we observe that this quantity here + + + align:start position:0% +P now we observe that this quantity here +is the probability that a geometric + + align:start position:0% +is the probability that a geometric + + + align:start position:0% +is the probability that a geometric +random variable takes the value of 3 + + align:start position:0% +random variable takes the value of 3 + + + align:start position:0% +random variable takes the value of 3 +here what have we calculated we have + + align:start position:0% +here what have we calculated we have + + + align:start position:0% +here what have we calculated we have +calculated the PMF of the random + + align:start position:0% +calculated the PMF of the random + + + align:start position:0% +calculated the PMF of the random +variable X minus 1 in a conditional + + align:start position:0% +variable X minus 1 in a conditional + + + align:start position:0% +variable X minus 1 in a conditional +universe where X is larger than 1 and we + + align:start position:0% +universe where X is larger than 1 and we + + + align:start position:0% +universe where X is larger than 1 and we +evaluated it for a value of 3 the + + align:start position:0% +evaluated it for a value of 3 the + + + align:start position:0% +evaluated it for a value of 3 the +probability that our random variable X + + align:start position:0% +probability that our random variable X + + + align:start position:0% +probability that our random variable X +minus 1 takes the value of 3 so what we + + align:start position:0% +minus 1 takes the value of 3 so what we + + + align:start position:0% +minus 1 takes the value of 3 so what we +have shown is that this conditional PMF + + align:start position:0% +have shown is that this conditional PMF + + + align:start position:0% +have shown is that this conditional PMF +is the same as the unconditional PMF now + + align:start position:0% +is the same as the unconditional PMF now + + + align:start position:0% +is the same as the unconditional PMF now +there is nothing special about the + + align:start position:0% +there is nothing special about the + + + align:start position:0% +there is nothing special about the +number 3 you can generalize this + + align:start position:0% +number 3 you can generalize this + + + align:start position:0% +number 3 you can generalize this +argument and establish that the + + align:start position:0% +argument and establish that the + + + align:start position:0% +argument and establish that the +conditional probability of X minus 1 + + align:start position:0% +conditional probability of X minus 1 + + + align:start position:0% +conditional probability of X minus 1 +given that X is strictly larger than 1 + + align:start position:0% +given that X is strictly larger than 1 + + + align:start position:0% +given that X is strictly larger than 1 +for any particular K is the same as the + + align:start position:0% +for any particular K is the same as the + + + align:start position:0% +for any particular K is the same as the +corresponding probability for the random + + align:start position:0% +corresponding probability for the random + + + align:start position:0% +corresponding probability for the random +variable X which is the t-one given by + + align:start position:0% +variable X which is the t-one given by + + + align:start position:0% +variable X which is the t-one given by +the geometric PMF finally there is + + align:start position:0% +the geometric PMF finally there is + + + align:start position:0% +the geometric PMF finally there is +nothing special about the value of 1 + + align:start position:0% +nothing special about the value of 1 + + + align:start position:0% +nothing special about the value of 1 +that we are using here in fact we can + + align:start position:0% +that we are using here in fact we can + + + align:start position:0% +that we are using here in fact we can +generalize and argue as follows suppose + + align:start position:0% +generalize and argue as follows suppose + + + align:start position:0% +generalize and argue as follows suppose +that I tell you that X is strictly + + align:start position:0% +that I tell you that X is strictly + + + align:start position:0% +that I tell you that X is strictly +larger than n that is the first n tosses + + align:start position:0% +larger than n that is the first n tosses + + + align:start position:0% +larger than n that is the first n tosses +resulted in tails once more + + align:start position:0% +resulted in tails once more + + + align:start position:0% +resulted in tails once more +these past tosses were wasted but have + + align:start position:0% +these past tosses were wasted but have + + + align:start position:0% +these past tosses were wasted but have +no effect on the future so the + + align:start position:0% +no effect on the future so the + + + align:start position:0% +no effect on the future so the +conditional PMF of the remaining number + + align:start position:0% +conditional PMF of the remaining number + + + align:start position:0% +conditional PMF of the remaining number +of tosses should be again the same + + align:start position:0% +of tosses should be again the same + + + align:start position:0% +of tosses should be again the same +therefore the statement were making is + + align:start position:0% +therefore the statement were making is + + + align:start position:0% +therefore the statement were making is +that this geometric PMF will also be the + + align:start position:0% +that this geometric PMF will also be the + + + align:start position:0% +that this geometric PMF will also be the +PMF of X minus n given that X is + + align:start position:0% +PMF of X minus n given that X is + + + align:start position:0% +PMF of X minus n given that X is +strictly larger than n and this will be + + align:start position:0% +strictly larger than n and this will be + + + align:start position:0% +strictly larger than n and this will be +true no matter what argument we plug in + + align:start position:0% +true no matter what argument we plug in + + + align:start position:0% +true no matter what argument we plug in +into the PMF + + align:start position:0% +into the PMF + + + align:start position:0% +into the PMF +we will now exploit the memorylessness + + align:start position:0% +we will now exploit the memorylessness + + + align:start position:0% +we will now exploit the memorylessness +property of the geometric PMF and use it + + align:start position:0% +property of the geometric PMF and use it + + + align:start position:0% +property of the geometric PMF and use it +together with the total expectation + + align:start position:0% +together with the total expectation + + + align:start position:0% +together with the total expectation +theorem to calculate the mean or + + align:start position:0% +theorem to calculate the mean or + + + align:start position:0% +theorem to calculate the mean or +expectation of the geometric PMF if we + + align:start position:0% +expectation of the geometric PMF if we + + + align:start position:0% +expectation of the geometric PMF if we +wanted to calculate the expected value + + align:start position:0% +wanted to calculate the expected value + + + align:start position:0% +wanted to calculate the expected value +of a geometric using the definition of + + align:start position:0% +of a geometric using the definition of + + + align:start position:0% +of a geometric using the definition of +the expectation we would have to + + align:start position:0% +the expectation we would have to + + + align:start position:0% +the expectation we would have to +calculate this infinite sum here which + + align:start position:0% +calculate this infinite sum here which + + + align:start position:0% +calculate this infinite sum here which +is quite difficult instead we're going + + align:start position:0% +is quite difficult instead we're going + + + align:start position:0% +is quite difficult instead we're going +to use a certain trick the trick is the + + align:start position:0% +to use a certain trick the trick is the + + + align:start position:0% +to use a certain trick the trick is the +following to break down the expected + + align:start position:0% +following to break down the expected + + + align:start position:0% +following to break down the expected +value calculation into two different + + align:start position:0% +value calculation into two different + + + align:start position:0% +value calculation into two different +scenarios under one scenario we obtain + + align:start position:0% +scenarios under one scenario we obtain + + + align:start position:0% +scenarios under one scenario we obtain +heads in the first tours and in that + + align:start position:0% +heads in the first tours and in that + + + align:start position:0% +heads in the first tours and in that +case the random variable X the number of + + align:start position:0% +case the random variable X the number of + + + align:start position:0% +case the random variable X the number of +tosses until the first head is equal to + + align:start position:0% +tosses until the first head is equal to + + + align:start position:0% +tosses until the first head is equal to +1 and this scenario occurs with + + align:start position:0% +1 and this scenario occurs with + + + align:start position:0% +1 and this scenario occurs with +probability P and we have another + + align:start position:0% +probability P and we have another + + + align:start position:0% +probability P and we have another +scenario with probability 1 minus P + + align:start position:0% +scenario with probability 1 minus P + + + align:start position:0% +scenario with probability 1 minus P +where we obtain tails in the first toss + + align:start position:0% +where we obtain tails in the first toss + + + align:start position:0% +where we obtain tails in the first toss +and in that case a random variable is + + align:start position:0% +and in that case a random variable is + + + align:start position:0% +and in that case a random variable is +strictly larger than 1 now the expected + + align:start position:0% +strictly larger than 1 now the expected + + + align:start position:0% +strictly larger than 1 now the expected +value of x consists of two pieces we + + align:start position:0% +value of x consists of two pieces we + + + align:start position:0% +value of x consists of two pieces we +have a first toss no matter what and + + align:start position:0% +have a first toss no matter what and + + + align:start position:0% +have a first toss no matter what and +then we have the number of remaining + + align:start position:0% +then we have the number of remaining + + + align:start position:0% +then we have the number of remaining +tosses which is X minus 1 so this is + + align:start position:0% +tosses which is X minus 1 so this is + + + align:start position:0% +tosses which is X minus 1 so this is +true by linearity of expectations now + + align:start position:0% +true by linearity of expectations now + + + align:start position:0% +true by linearity of expectations now +the expected value of X minus 1 consists + + align:start position:0% +the expected value of X minus 1 consists + + + align:start position:0% +the expected value of X minus 1 consists +of two pieces using the total + + align:start position:0% +of two pieces using the total + + + align:start position:0% +of two pieces using the total +expectation theorem the probability of + + align:start position:0% +expectation theorem the probability of + + + align:start position:0% +expectation theorem the probability of +the first scenario times the expected + + align:start position:0% +the first scenario times the expected + + + align:start position:0% +the first scenario times the expected +value of X minus 1 given that X is equal + + align:start position:0% +value of X minus 1 given that X is equal + + + align:start position:0% +value of X minus 1 given that X is equal +to 1 plus 1 minus P the probability of + + align:start position:0% +to 1 plus 1 minus P the probability of + + + align:start position:0% +to 1 plus 1 minus P the probability of +the second scenario times the expected + + align:start position:0% +the second scenario times the expected + + + align:start position:0% +the second scenario times the expected +value of X minus 1 given that X is + + align:start position:0% +value of X minus 1 given that X is + + + align:start position:0% +value of X minus 1 given that X is +bigger than 1 + + align:start position:0% + + + + align:start position:0% + +now this term here is zero + + align:start position:0% +now this term here is zero + + + align:start position:0% +now this term here is zero +why if I tell you that X is equal to one + + align:start position:0% +why if I tell you that X is equal to one + + + align:start position:0% +why if I tell you that X is equal to one +then you are certain that X minus one is + + align:start position:0% +then you are certain that X minus one is + + + align:start position:0% +then you are certain that X minus one is +equal to 0 so this term gives a zero + + align:start position:0% +equal to 0 so this term gives a zero + + + align:start position:0% +equal to 0 so this term gives a zero +contribution how about the next term we + + align:start position:0% +contribution how about the next term we + + + align:start position:0% +contribution how about the next term we +have a 1 minus P here times this + + align:start position:0% +have a 1 minus P here times this + + + align:start position:0% +have a 1 minus P here times this +expected value now this random variable + + align:start position:0% +expected value now this random variable + + + align:start position:0% +expected value now this random variable +conditioned on this event has the same + + align:start position:0% +conditioned on this event has the same + + + align:start position:0% +conditioned on this event has the same +distribution as an ordinary + + align:start position:0% +distribution as an ordinary + + + align:start position:0% +distribution as an ordinary +unconditioned geometric random variable + + align:start position:0% +unconditioned geometric random variable + + + align:start position:0% +unconditioned geometric random variable +so this expectation here must be the + + align:start position:0% +so this expectation here must be the + + + align:start position:0% +so this expectation here must be the +same as the expectation of an ordinary + + align:start position:0% +same as the expectation of an ordinary + + + align:start position:0% +same as the expectation of an ordinary +unconditioned geometric random variable + + align:start position:0% +unconditioned geometric random variable + + + align:start position:0% +unconditioned geometric random variable +and this gives us an equality both sides + + align:start position:0% +and this gives us an equality both sides + + + align:start position:0% +and this gives us an equality both sides +involve the expected value of x but we + + align:start position:0% +involve the expected value of x but we + + + align:start position:0% +involve the expected value of x but we +can solve this equation for the expected + + align:start position:0% +can solve this equation for the expected + + + align:start position:0% +can solve this equation for the expected +value and we obtain the end result that + + align:start position:0% +value and we obtain the end result that + + + align:start position:0% +value and we obtain the end result that +the expected value is 1 over P by the + + align:start position:0% +the expected value is 1 over P by the + + + align:start position:0% +the expected value is 1 over P by the +way this answer makes intuitive sense if + + align:start position:0% +way this answer makes intuitive sense if + + + align:start position:0% +way this answer makes intuitive sense if +P is small this means that the odds of + + align:start position:0% +P is small this means that the odds of + + + align:start position:0% +P is small this means that the odds of +seeing heads is small then in that case + + align:start position:0% +seeing heads is small then in that case + + + align:start position:0% +seeing heads is small then in that case +we need to wait longer and longer until + + align:start position:0% +we need to wait longer and longer until + + + align:start position:0% +we need to wait longer and longer until +we see heads for the first time setting + + align:start position:0% +we see heads for the first time setting + + + align:start position:0% +we see heads for the first time setting +aside the specific form of the answer + + align:start position:0% +aside the specific form of the answer + + + align:start position:0% +aside the specific form of the answer +that we found what we have just done + + align:start position:0% +that we found what we have just done + + + align:start position:0% +that we found what we have just done +actually illustrates that fairly + + align:start position:0% +actually illustrates that fairly + + + align:start position:0% +actually illustrates that fairly +difficult calculations can become very + + align:start position:0% +difficult calculations can become very + + + align:start position:0% +difficult calculations can become very +simple if one breaks down a model or a + + align:start position:0% +simple if one breaks down a model or a + + + align:start position:0% +simple if one breaks down a model or a +problem in a clever way this is going to + + align:start position:0% +problem in a clever way this is going to + + + align:start position:0% +problem in a clever way this is going to +be a recurrent theme throughout this + + align:start position:0% +be a recurrent theme throughout this + + + align:start position:0% +be a recurrent theme throughout this +class \ No newline at end of file diff --git a/N-67gRDE3UQ.txt b/N-67gRDE3UQ.txt new file mode 100644 index 0000000000000000000000000000000000000000..f30eaf611e52c9b46aaef15f0d6dcd836165201b --- /dev/null +++ b/N-67gRDE3UQ.txt @@ -0,0 +1,14939 @@ +align:start position:0% + +foreign + + align:start position:0% + + + + align:start position:0% + +to examining empirical things + + align:start position:0% +to examining empirical things + + + align:start position:0% +to examining empirical things +you guys have read my paper I'm going to + + align:start position:0% +you guys have read my paper I'm going to + + + align:start position:0% +you guys have read my paper I'm going to +talk a bit about that and I'm going to + + align:start position:0% +talk a bit about that and I'm going to + + + align:start position:0% +talk a bit about that and I'm going to +talk also about it on on Monday so some + + align:start position:0% +talk also about it on on Monday so some + + + align:start position:0% +talk also about it on on Monday so some +of the questions that you had many of + + align:start position:0% +of the questions that you had many of + + + align:start position:0% +of the questions that you had many of +the questions comments you had were on + + align:start position:0% +the questions comments you had were on + + + align:start position:0% +the questions comments you had were on +the returns to education piece and those + + align:start position:0% +the returns to education piece and those + + + align:start position:0% +the returns to education piece and those +we'll discuss we'll discuss on Monday + + align:start position:0% +we'll discuss we'll discuss on Monday + + + align:start position:0% +we'll discuss we'll discuss on Monday +but there are a number of things that + + align:start position:0% +but there are a number of things that + + + align:start position:0% +but there are a number of things that +come up that should uh that should be + + align:start position:0% +come up that should uh that should be + + + align:start position:0% +come up that should uh that should be +able to address today + + align:start position:0% +able to address today + + + align:start position:0% +able to address today +so if you remember we we ended up last + + align:start position:0% +so if you remember we we ended up last + + + align:start position:0% +so if you remember we we ended up last +time by saying oh we at some point uh + + align:start position:0% +time by saying oh we at some point uh + + + align:start position:0% +time by saying oh we at some point uh +alas um on Monday we had this equation + + align:start position:0% +alas um on Monday we had this equation + + + align:start position:0% +alas um on Monday we had this equation +that the level of Education chosen by a + + align:start position:0% +that the level of Education chosen by a + + + align:start position:0% +that the level of Education chosen by a +family for their kids is going to be a + + align:start position:0% +family for their kids is going to be a + + + align:start position:0% +family for their kids is going to be a +function of the costs of Education the + + align:start position:0% +function of the costs of Education the + + + align:start position:0% +function of the costs of Education the +marginal cost for them of acquiring one + + align:start position:0% +marginal cost for them of acquiring one + + + align:start position:0% +marginal cost for them of acquiring one +more unit of human capital and of the + + align:start position:0% +more unit of human capital and of the + + + align:start position:0% +more unit of human capital and of the +returns to education both the immediate + + align:start position:0% +returns to education both the immediate + + + align:start position:0% +returns to education both the immediate +financial return in the form of wages as + + align:start position:0% +financial return in the form of wages as + + + align:start position:0% +financial return in the form of wages as +well as + + align:start position:0% +well as + + + align:start position:0% +well as +the human how is it it's going to + + align:start position:0% +the human how is it it's going to + + + align:start position:0% +the human how is it it's going to +acquire the human capital of the Next + + align:start position:0% +acquire the human capital of the Next + + + align:start position:0% +acquire the human capital of the Next +Generation so this is these are all + + align:start position:0% +Generation so this is these are all + + + align:start position:0% +Generation so this is these are all +things that people have been looked at + + align:start position:0% +things that people have been looked at + + + align:start position:0% +things that people have been looked at +I've looked at + + align:start position:0% +I've looked at + + + align:start position:0% +I've looked at +uh so we should expect people to respond + + align:start position:0% +uh so we should expect people to respond + + + align:start position:0% +uh so we should expect people to respond +both to costs and benefits + + align:start position:0% +both to costs and benefits + + + align:start position:0% +both to costs and benefits +so the cost piece seems relatively + + align:start position:0% +so the cost piece seems relatively + + + align:start position:0% +so the cost piece seems relatively +straightforward uh one would look for a + + align:start position:0% +straightforward uh one would look for a + + + align:start position:0% +straightforward uh one would look for a +setting where cost to education director + + align:start position:0% +setting where cost to education director + + + align:start position:0% +setting where cost to education director +in in direct went down and then look at + + align:start position:0% +in in direct went down and then look at + + + align:start position:0% +in in direct went down and then look at +and look at whether people respond by + + align:start position:0% +and look at whether people respond by + + + align:start position:0% +and look at whether people respond by +educating their kids more + + align:start position:0% +educating their kids more + + + align:start position:0% +educating their kids more +and then the benefits is whether people + + align:start position:0% +and then the benefits is whether people + + + align:start position:0% +and then the benefits is whether people +respond to returns to education that + + align:start position:0% +respond to returns to education that + + + align:start position:0% +respond to returns to education that +might be a little bit more + + align:start position:0% +might be a little bit more + + + align:start position:0% +might be a little bit more +tricky and we are going to do a bit of + + align:start position:0% +tricky and we are going to do a bit of + + + align:start position:0% +tricky and we are going to do a bit of +that + + align:start position:0% +that + + + align:start position:0% +that +both the actual benefits and the + + align:start position:0% +both the actual benefits and the + + + align:start position:0% +both the actual benefits and the +perceived benefits which of course is in + + align:start position:0% +perceived benefits which of course is in + + + align:start position:0% +perceived benefits which of course is in +this equation implicitly something we + + align:start position:0% +this equation implicitly something we + + + align:start position:0% +this equation implicitly something we +hardly discussed but just a little bit + + align:start position:0% +hardly discussed but just a little bit + + + align:start position:0% +hardly discussed but just a little bit +last time is whether the perceived + + align:start position:0% +last time is whether the perceived + + + align:start position:0% +last time is whether the perceived +benefits are the same as the real + + align:start position:0% +benefits are the same as the real + + + align:start position:0% +benefits are the same as the real +benefits + + align:start position:0% +benefits + + + align:start position:0% +benefits +so let's start with the customers that's + + align:start position:0% +so let's start with the customers that's + + + align:start position:0% +so let's start with the customers that's +sort of the straightforward piece + + align:start position:0% +sort of the straightforward piece + + + align:start position:0% +sort of the straightforward piece +so there are a number of papers that + + align:start position:0% +so there are a number of papers that + + + align:start position:0% +so there are a number of papers that +look at the reaction to the direct cost + + align:start position:0% +look at the reaction to the direct cost + + + align:start position:0% +look at the reaction to the direct cost +of education so + + align:start position:0% +of education so + + + align:start position:0% +of education so +um + + align:start position:0% +um + + + align:start position:0% +um +in particular but this is a bit of a + + align:start position:0% +in particular but this is a bit of a + + + align:start position:0% +in particular but this is a bit of a +biased review of the literature because + + align:start position:0% +biased review of the literature because + + + align:start position:0% +biased review of the literature because +it has mostly my papers but I have a + + align:start position:0% +it has mostly my papers but I have a + + + align:start position:0% +it has mostly my papers but I have a +paper with Pascal in Japan Michael + + align:start position:0% +paper with Pascal in Japan Michael + + + align:start position:0% +paper with Pascal in Japan Michael +camera where we provide the school + + align:start position:0% +camera where we provide the school + + + align:start position:0% +camera where we provide the school +uniforms + + align:start position:0% +uniforms + + + align:start position:0% +uniforms +for kids in you know entering grade + + align:start position:0% +for kids in you know entering grade + + + align:start position:0% +for kids in you know entering grade +seven or grade uh grade six or seven or + + align:start position:0% +seven or grade uh grade six or seven or + + + align:start position:0% +seven or grade uh grade six or seven or +eight + + align:start position:0% +eight + + + align:start position:0% +eight +and we found pretty large effect there + + align:start position:0% +and we found pretty large effect there + + + align:start position:0% +and we found pretty large effect there +we then have a literature that we'll + + align:start position:0% +we then have a literature that we'll + + + align:start position:0% +we then have a literature that we'll +discuss in much more detail we have a + + align:start position:0% +discuss in much more detail we have a + + + align:start position:0% +discuss in much more detail we have a +paper on the secondary school to + + align:start position:0% +paper on the secondary school to + + + align:start position:0% +paper on the secondary school to +education which are much larger than the + + align:start position:0% +education which are much larger than the + + + align:start position:0% +education which are much larger than the +school uniform uh which which we'll + + align:start position:0% +school uniform uh which which we'll + + + align:start position:0% +school uniform uh which which we'll +discuss in the detail on Monday and + + align:start position:0% +discuss in the detail on Monday and + + + align:start position:0% +discuss in the detail on Monday and +you're gonna read uh which again show + + align:start position:0% +you're gonna read uh which again show + + + align:start position:0% +you're gonna read uh which again show +pretty large impact + + align:start position:0% +pretty large impact + + + align:start position:0% +pretty large impact +in a sense what is and Michael as other + + align:start position:0% +in a sense what is and Michael as other + + + align:start position:0% +in a sense what is and Michael as other +people with other people on various form + + align:start position:0% +people with other people on various form + + + align:start position:0% +people with other people on various form +of scholarships for schools + + align:start position:0% +of scholarships for schools + + + align:start position:0% +of scholarships for schools +um + + align:start position:0% +um + + + align:start position:0% +um +so this literature is interesting I + + align:start position:0% +so this literature is interesting I + + + align:start position:0% +so this literature is interesting I +don't I in particular the uniform + + align:start position:0% +don't I in particular the uniform + + + align:start position:0% +don't I in particular the uniform +literature because on the one hand you + + align:start position:0% +literature because on the one hand you + + + align:start position:0% +literature because on the one hand you +you think uh effect impact of paying for + + align:start position:0% +you think uh effect impact of paying for + + + align:start position:0% +you think uh effect impact of paying for +uniform on on schooling + + align:start position:0% +uniform on on schooling + + + align:start position:0% +uniform on on schooling +so that would suggest that people are + + align:start position:0% +so that would suggest that people are + + + align:start position:0% +so that would suggest that people are +you know appropriately responding to + + align:start position:0% +you know appropriately responding to + + + align:start position:0% +you know appropriately responding to +cost + + align:start position:0% +cost + + + align:start position:0% +cost +on the other hand these impacts are + + align:start position:0% +on the other hand these impacts are + + + align:start position:0% +on the other hand these impacts are +really large + + align:start position:0% +really large + + + align:start position:0% +really large +uh really really large so you get for + + align:start position:0% +uh really really large so you get for + + + align:start position:0% +uh really really large so you get for +example in our uniform paper you get + + align:start position:0% +example in our uniform paper you get + + + align:start position:0% +example in our uniform paper you get +reduction in in Dropout of a few + + align:start position:0% +reduction in in Dropout of a few + + + align:start position:0% +reduction in in Dropout of a few +percentage points and the cost of a + + align:start position:0% +percentage points and the cost of a + + + align:start position:0% +percentage points and the cost of a +school uniform is is five dollars or so + + align:start position:0% +school uniform is is five dollars or so + + + align:start position:0% +school uniform is is five dollars or so +so with even for a Kenyan family is not + + align:start position:0% +so with even for a Kenyan family is not + + + align:start position:0% +so with even for a Kenyan family is not +that big + + align:start position:0% +that big + + + align:start position:0% +that big +so that is + + align:start position:0% +so that is + + + align:start position:0% +so that is +at this on the one hand you get the + + align:start position:0% +at this on the one hand you get the + + + align:start position:0% +at this on the one hand you get the +magnitude right on the other hand it is + + align:start position:0% +magnitude right on the other hand it is + + + align:start position:0% +magnitude right on the other hand it is +not really I would say a Vindication of + + align:start position:0% +not really I would say a Vindication of + + + align:start position:0% +not really I would say a Vindication of +this model because the impacts are too + + align:start position:0% +this model because the impacts are too + + + align:start position:0% +this model because the impacts are too +large + + align:start position:0% +large + + + align:start position:0% +large +in the sense that it if it if if the + + align:start position:0% +in the sense that it if it if if the + + + align:start position:0% +in the sense that it if it if if the +only reason why the cost to education + + align:start position:0% +only reason why the cost to education + + + align:start position:0% +only reason why the cost to education +enter is you're comparing them to the + + align:start position:0% +enter is you're comparing them to the + + + align:start position:0% +enter is you're comparing them to the +interest rate then clearly uh I know to + + align:start position:0% +interest rate then clearly uh I know to + + + align:start position:0% +interest rate then clearly uh I know to +into the the benefits and appropriately + + align:start position:0% +into the the benefits and appropriately + + + align:start position:0% +into the the benefits and appropriately +discounted by the interest rate then + + align:start position:0% +discounted by the interest rate then + + + align:start position:0% +discounted by the interest rate then +that seems way too large + + align:start position:0% +that seems way too large + + + align:start position:0% +that seems way too large +either indicating huge credit constraint + + align:start position:0% +either indicating huge credit constraint + + + align:start position:0% +either indicating huge credit constraint +that they can't even fight five dollars + + align:start position:0% +that they can't even fight five dollars + + + align:start position:0% +that they can't even fight five dollars +or something else is is going on + + align:start position:0% + + + + align:start position:0% + +why did you think about + + align:start position:0% +why did you think about + + + align:start position:0% +why did you think about +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +mustard + + align:start position:0% +mustard + + + align:start position:0% +mustard +everybody says it's a big deal like + + align:start position:0% +everybody says it's a big deal like + + + align:start position:0% +everybody says it's a big deal like +everybody says it's a big deal in fact + + align:start position:0% +everybody says it's a big deal in fact + + + align:start position:0% +everybody says it's a big deal in fact +we got to uniform we this is a paper + + align:start position:0% +we got to uniform we this is a paper + + + align:start position:0% +we got to uniform we this is a paper +where we looked at the + + align:start position:0% +where we looked at the + + + align:start position:0% +where we looked at the +HIV uh we looked at we we were very + + align:start position:0% +HIV uh we looked at we we were very + + + align:start position:0% +HIV uh we looked at we we were very +interested in in testing the impact of + + align:start position:0% +interested in in testing the impact of + + + align:start position:0% +interested in in testing the impact of +the government HIV uh school um + + align:start position:0% +the government HIV uh school um + + + align:start position:0% +the government HIV uh school um +intervention so the government in Kenya + + align:start position:0% +intervention so the government in Kenya + + + align:start position:0% +intervention so the government in Kenya +was introducing a new program for HIV + + align:start position:0% +was introducing a new program for HIV + + + align:start position:0% +was introducing a new program for HIV +um + + align:start position:0% +um + + + align:start position:0% +um +which we actually were reasonably + + align:start position:0% +which we actually were reasonably + + + align:start position:0% +which we actually were reasonably +skeptical about this is called the ABCD + + align:start position:0% +skeptical about this is called the ABCD + + + align:start position:0% +skeptical about this is called the ABCD +strategy which was followed at the time + + align:start position:0% +strategy which was followed at the time + + + align:start position:0% +strategy which was followed at the time +by most country in East Africa + + align:start position:0% +by most country in East Africa + + + align:start position:0% +by most country in East Africa +that stands for abstain be careful use a + + align:start position:0% +that stands for abstain be careful use a + + + align:start position:0% +that stands for abstain be careful use a +condom or you die + + align:start position:0% +condom or you die + + + align:start position:0% +condom or you die +um that was relatively uh kind of + + align:start position:0% +um that was relatively uh kind of + + + align:start position:0% +um that was relatively uh kind of +fear-mongering among in this orders who + + align:start position:0% +fear-mongering among in this orders who + + + align:start position:0% +fear-mongering among in this orders who +abstain is the best be faithful user + + align:start position:0% +abstain is the best be faithful user + + + align:start position:0% +abstain is the best be faithful user +condom or you die so this was a an + + align:start position:0% +condom or you die so this was a an + + + align:start position:0% +condom or you die so this was a an +example of what's called a risk of + + align:start position:0% +example of what's called a risk of + + + align:start position:0% +example of what's called a risk of +avoiding all risk risk avoidance + + align:start position:0% +avoiding all risk risk avoidance + + + align:start position:0% +avoiding all risk risk avoidance +strategy as opposed to risk mitigation + + align:start position:0% +strategy as opposed to risk mitigation + + + align:start position:0% +strategy as opposed to risk mitigation +strategy + + align:start position:0% +strategy + + + align:start position:0% +strategy +so this program was introduced among + + align:start position:0% +so this program was introduced among + + + align:start position:0% +so this program was introduced among +upper Primary School students this is + + align:start position:0% +upper Primary School students this is + + + align:start position:0% +upper Primary School students this is +grade six to eight uh in Kenya we were + + align:start position:0% +grade six to eight uh in Kenya we were + + + align:start position:0% +grade six to eight uh in Kenya we were +they were interested in evaluating and + + align:start position:0% +they were interested in evaluating and + + + align:start position:0% +they were interested in evaluating and +we were interested in evaluating it but + + align:start position:0% +we were interested in evaluating it but + + + align:start position:0% +we were interested in evaluating it but +at the same time we were quite skeptical + + align:start position:0% +at the same time we were quite skeptical + + + align:start position:0% +at the same time we were quite skeptical +and we wanted to compare that with the + + align:start position:0% +and we wanted to compare that with the + + + align:start position:0% +and we wanted to compare that with the +strategy that is just keeping girls in + + align:start position:0% +strategy that is just keeping girls in + + + align:start position:0% +strategy that is just keeping girls in +school + + align:start position:0% +school + + + align:start position:0% +school +as a direct protective uh measure as + + align:start position:0% +as a direct protective uh measure as + + + align:start position:0% +as a direct protective uh measure as +opposed to trying to teach them + + align:start position:0% +opposed to trying to teach them + + + align:start position:0% +opposed to trying to teach them +something on HIV when they're in school + + align:start position:0% +something on HIV when they're in school + + + align:start position:0% +something on HIV when they're in school +so we wanted to have that + + align:start position:0% +so we wanted to have that + + + align:start position:0% +so we wanted to have that +and um it was pretty obvious to us that + + align:start position:0% +and um it was pretty obvious to us that + + + align:start position:0% +and um it was pretty obvious to us that +for for kids that age the uniform is a + + align:start position:0% +for for kids that age the uniform is a + + + align:start position:0% +for for kids that age the uniform is a +big constraint they cannot go to school + + align:start position:0% +big constraint they cannot go to school + + + align:start position:0% +big constraint they cannot go to school +without the uniform the school send them + + align:start position:0% +without the uniform the school send them + + + align:start position:0% +without the uniform the school send them +back without the uniform primaries + + align:start position:0% +back without the uniform primaries + + + align:start position:0% +back without the uniform primaries +initially when we started the project + + align:start position:0% +initially when we started the project + + + align:start position:0% +initially when we started the project +conceiving of the project there were + + align:start position:0% +conceiving of the project there were + + + align:start position:0% +conceiving of the project there were +school fees so we were going to pay for + + align:start position:0% +school fees so we were going to pay for + + + align:start position:0% +school fees so we were going to pay for +the school fee and the school fee went + + align:start position:0% +the school fee and the school fee went + + + align:start position:0% +the school fee and the school fee went +to West so we uh but we realized that + + align:start position:0% +to West so we uh but we realized that + + + align:start position:0% +to West so we uh but we realized that +the uniform were still a barrier so + + align:start position:0% +the uniform were still a barrier so + + + align:start position:0% +the uniform were still a barrier so +that's why we did the program even + + align:start position:0% +that's why we did the program even + + + align:start position:0% +that's why we did the program even +though + + align:start position:0% +though + + + align:start position:0% +though +if you think about it from the comfort + + align:start position:0% +if you think about it from the comfort + + + align:start position:0% +if you think about it from the comfort +of your office people shouldn't really + + align:start position:0% +of your office people shouldn't really + + + align:start position:0% +of your office people shouldn't really +be responsive to the cost of to the + + align:start position:0% +be responsive to the cost of to the + + + align:start position:0% +be responsive to the cost of to the +presence of the uniform but as it turns + + align:start position:0% +presence of the uniform but as it turns + + + align:start position:0% +presence of the uniform but as it turns +out they are + + align:start position:0% +out they are + + + align:start position:0% +out they are +so that's kind of how we came to to that + + align:start position:0% +so that's kind of how we came to to that + + + align:start position:0% +so that's kind of how we came to to that +it was less of + + align:start position:0% +it was less of + + + align:start position:0% +it was less of +and the results are pretty interesting + + align:start position:0% +and the results are pretty interesting + + + align:start position:0% +and the results are pretty interesting +in the sense that keeping just + + align:start position:0% +in the sense that keeping just + + + align:start position:0% +in the sense that keeping just +going keeping kids in school keeping + + align:start position:0% +going keeping kids in school keeping + + + align:start position:0% +going keeping kids in school keeping +girls in school does reduce HIV that + + align:start position:0% +girls in school does reduce HIV that + + + align:start position:0% +girls in school does reduce HIV that +program doesn't work + + align:start position:0% +program doesn't work + + + align:start position:0% +program doesn't work +and in fact that program endures the + + align:start position:0% +and in fact that program endures the + + + align:start position:0% +and in fact that program endures the +effect of the of keeping girls in school + + align:start position:0% +effect of the of keeping girls in school + + + align:start position:0% +effect of the of keeping girls in school +um so it is better to just pay for the + + align:start position:0% +um so it is better to just pay for the + + + align:start position:0% +um so it is better to just pay for the +uniform and do nothing else that's worse + + align:start position:0% +uniform and do nothing else that's worse + + + align:start position:0% +uniform and do nothing else that's worse +that it is worse than trying to teach + + align:start position:0% +that it is worse than trying to teach + + + align:start position:0% +that it is worse than trying to teach +them the ABCD program while they're in + + align:start position:0% +them the ABCD program while they're in + + + align:start position:0% +them the ABCD program while they're in +school + + align:start position:0% +school + + + align:start position:0% +school +for instance that we probably will get + + align:start position:0% +for instance that we probably will get + + + align:start position:0% +for instance that we probably will get +into when we talk more about health so + + align:start position:0% +into when we talk more about health so + + + align:start position:0% +into when we talk more about health so +that's that's how this this came about + + align:start position:0% +that's that's how this this came about + + + align:start position:0% +that's that's how this this came about +so this is like something that everybody + + align:start position:0% +so this is like something that everybody + + + align:start position:0% +so this is like something that everybody +talks about the school uniform even + + align:start position:0% +talks about the school uniform even + + + align:start position:0% +talks about the school uniform even +though + + align:start position:0% +though + + + align:start position:0% +though +this is not consistent with this model + + align:start position:0% +this is not consistent with this model + + + align:start position:0% +this is not consistent with this model +uh but that's probably a failure of the + + align:start position:0% +uh but that's probably a failure of the + + + align:start position:0% +uh but that's probably a failure of the +model as opposed to a failure of + + align:start position:0% +model as opposed to a failure of + + + align:start position:0% +model as opposed to a failure of +people's thinking + + align:start position:0% +people's thinking + + + align:start position:0% +people's thinking +so that's the first set of costs so I + + align:start position:0% +so that's the first set of costs so I + + + align:start position:0% +so that's the first set of costs so I +would say just as a Vindication of this + + align:start position:0% +would say just as a Vindication of this + + + align:start position:0% +would say just as a Vindication of this +model + + align:start position:0% +model + + + align:start position:0% +model +it's not very uh it's a bit half up + + align:start position:0% +it's not very uh it's a bit half up + + + align:start position:0% +it's not very uh it's a bit half up +because on the one hand you see people + + align:start position:0% +because on the one hand you see people + + + align:start position:0% +because on the one hand you see people +responded to cost on the other and + + align:start position:0% +responded to cost on the other and + + + align:start position:0% +responded to cost on the other and +they're way too responsive + + align:start position:0% +they're way too responsive + + + align:start position:0% +they're way too responsive +then there are the indirect costs which + + align:start position:0% +then there are the indirect costs which + + + align:start position:0% +then there are the indirect costs which +is the opportunity cost of being in + + align:start position:0% +is the opportunity cost of being in + + + align:start position:0% +is the opportunity cost of being in +schools while you're in school you you + + align:start position:0% +schools while you're in school you you + + + align:start position:0% +schools while you're in school you you +don't make money for the family + + align:start position:0% +don't make money for the family + + + align:start position:0% +don't make money for the family +and it is believed in particular for + + align:start position:0% +and it is believed in particular for + + + align:start position:0% +and it is believed in particular for +slightly older students middle school + + align:start position:0% +slightly older students middle school + + + align:start position:0% +slightly older students middle school +high school that it it's prevents some + + align:start position:0% +high school that it it's prevents some + + + align:start position:0% +high school that it it's prevents some +kids from being in school and this is + + align:start position:0% +kids from being in school and this is + + + align:start position:0% +kids from being in school and this is +one of the motivation of conditional + + align:start position:0% +one of the motivation of conditional + + + align:start position:0% +one of the motivation of conditional +cash transfer programs which were + + align:start position:0% +cash transfer programs which were + + + align:start position:0% +cash transfer programs which were +introduced initially in Latin America + + align:start position:0% +introduced initially in Latin America + + + align:start position:0% +introduced initially in Latin America +which has a comp which has a component + + align:start position:0% +which has a comp which has a component + + + align:start position:0% +which has a comp which has a component +that is a conditional on sending kids to + + align:start position:0% +that is a conditional on sending kids to + + + align:start position:0% +that is a conditional on sending kids to +school and the idea is that that's + + align:start position:0% +school and the idea is that that's + + + align:start position:0% +school and the idea is that that's +actually a fair amount of money that + + align:start position:0% +actually a fair amount of money that + + + align:start position:0% +actually a fair amount of money that +people get from the condition cash + + align:start position:0% +people get from the condition cash + + + align:start position:0% +people get from the condition cash +transfer + + align:start position:0% +transfer + + + align:start position:0% +transfer +and it generates so as long as your kids + + align:start position:0% +and it generates so as long as your kids + + + align:start position:0% +and it generates so as long as your kids +Goes to School regularly and it's not + + align:start position:0% +Goes to School regularly and it's not + + + align:start position:0% +Goes to School regularly and it's not +absent too much it's enroll in an absent + + align:start position:0% +absent too much it's enroll in an absent + + + align:start position:0% +absent too much it's enroll in an absent +too much you get a transfer monthly + + align:start position:0% +too much you get a transfer monthly + + + align:start position:0% +too much you get a transfer monthly +so that sort of compensate for not + + align:start position:0% +so that sort of compensate for not + + + align:start position:0% +so that sort of compensate for not +having + + align:start position:0% +having + + + align:start position:0% +having +for not having the uh their earnings if + + align:start position:0% +for not having the uh their earnings if + + + align:start position:0% +for not having the uh their earnings if +they worked on the market or on a farm + + align:start position:0% +they worked on the market or on a farm + + + align:start position:0% +they worked on the market or on a farm +or something like that so that's sort of + + align:start position:0% +or something like that so that's sort of + + + align:start position:0% +or something like that so that's sort of +that's also a way of manipulating the + + align:start position:0% +that's also a way of manipulating the + + + align:start position:0% +that's also a way of manipulating the +cost to education by creating a benefit + + align:start position:0% +cost to education by creating a benefit + + + align:start position:0% +cost to education by creating a benefit +that of sets an existing cost + + align:start position:0% +that of sets an existing cost + + + align:start position:0% +that of sets an existing cost +so that's a form of uh in in the cash + + align:start position:0% +so that's a form of uh in in the cash + + + align:start position:0% +so that's a form of uh in in the cash +transfer + + align:start position:0% +transfer + + + align:start position:0% +transfer +um + + align:start position:0% +um + + + align:start position:0% +um +there again I would say the results the + + align:start position:0% +there again I would say the results the + + + align:start position:0% +there again I would say the results the +evidence to want you know + + align:start position:0% +evidence to want you know + + + align:start position:0% +evidence to want you know +in favor of this model and relatively is + + align:start position:0% +in favor of this model and relatively is + + + align:start position:0% +in favor of this model and relatively is +is mixed because on the one hand people + + align:start position:0% +is mixed because on the one hand people + + + align:start position:0% +is mixed because on the one hand people +are very responsive to conditional cash + + align:start position:0% +are very responsive to conditional cash + + + align:start position:0% +are very responsive to conditional cash +transfer you do uh they are now been + + align:start position:0% +transfer you do uh they are now been + + + align:start position:0% +transfer you do uh they are now been +evaluating in in dozens of countries + + align:start position:0% +evaluating in in dozens of countries + + + align:start position:0% +evaluating in in dozens of countries +starting with the evaluation in Mexico + + align:start position:0% +starting with the evaluation in Mexico + + + align:start position:0% +starting with the evaluation in Mexico +which was one of the first big prominent + + align:start position:0% +which was one of the first big prominent + + + align:start position:0% +which was one of the first big prominent +City in development + + align:start position:0% +City in development + + + align:start position:0% +City in development +it was kind of replicated in lots of + + align:start position:0% +it was kind of replicated in lots of + + + align:start position:0% +it was kind of replicated in lots of +countries and + + align:start position:0% +countries and + + + align:start position:0% +countries and +maybe bizarrely enough because the first + + align:start position:0% +maybe bizarrely enough because the first + + + align:start position:0% +maybe bizarrely enough because the first +one was done with an experiment + + align:start position:0% +one was done with an experiment + + + align:start position:0% +one was done with an experiment +everybody so they had to have their + + align:start position:0% +everybody so they had to have their + + + align:start position:0% +everybody so they had to have their +experiment too so it was experimented in + + align:start position:0% +experiment too so it was experimented in + + + align:start position:0% +experiment too so it was experimented in +many many many different places + + align:start position:0% +many many many different places + + + align:start position:0% +many many many different places +and in and you tend to always find uh + + align:start position:0% +and in and you tend to always find uh + + + align:start position:0% +and in and you tend to always find uh +impact on education particularly uh for + + align:start position:0% +impact on education particularly uh for + + + align:start position:0% +impact on education particularly uh for +these older kids + + align:start position:0% +these older kids + + + align:start position:0% +these older kids +so that would be good you know that sort + + align:start position:0% +so that would be good you know that sort + + + align:start position:0% +so that would be good you know that sort +of people respond to the cost of + + align:start position:0% +of people respond to the cost of + + + align:start position:0% +of people respond to the cost of +Education + + align:start position:0% +Education + + + align:start position:0% +Education +however + + align:start position:0% +however + + + align:start position:0% +however +they also response when the when the + + align:start position:0% +they also response when the when the + + + align:start position:0% +they also response when the when the +cash transfer are unconditional + + align:start position:0% +cash transfer are unconditional + + + align:start position:0% +cash transfer are unconditional +and there again remember in our model an + + align:start position:0% +and there again remember in our model an + + + align:start position:0% +and there again remember in our model an +easier just a little lump sum transfer + + align:start position:0% +easier just a little lump sum transfer + + + align:start position:0% +easier just a little lump sum transfer +shouldn't have an impact + + align:start position:0% +shouldn't have an impact + + + align:start position:0% +shouldn't have an impact +well you could say maybe it's credit + + align:start position:0% +well you could say maybe it's credit + + + align:start position:0% +well you could say maybe it's credit +constraint or something like that but + + align:start position:0% +constraint or something like that but + + + align:start position:0% +constraint or something like that but +um + + align:start position:0% + + + + align:start position:0% + +it's certainly not directly uh a + + align:start position:0% +it's certainly not directly uh a + + + align:start position:0% +it's certainly not directly uh a +response to the cost to education so + + align:start position:0% +response to the cost to education so + + + align:start position:0% +response to the cost to education so +people are just about + + align:start position:0% +people are just about + + + align:start position:0% +people are just about +in some studies you find them somewhat + + align:start position:0% +in some studies you find them somewhat + + + align:start position:0% +in some studies you find them somewhat +more responsive to conditional cash + + align:start position:0% +more responsive to conditional cash + + + align:start position:0% +more responsive to conditional cash +transfer in many studies there is no + + align:start position:0% +transfer in many studies there is no + + + align:start position:0% +transfer in many studies there is no +difference so we did one in Morocco for + + align:start position:0% +difference so we did one in Morocco for + + + align:start position:0% +difference so we did one in Morocco for +example where we found + + align:start position:0% +example where we found + + + align:start position:0% +example where we found +that conditional and unconditional + + align:start position:0% +that conditional and unconditional + + + align:start position:0% +that conditional and unconditional +transfer are more or less equivalent + + align:start position:0% +transfer are more or less equivalent + + + align:start position:0% +transfer are more or less equivalent +with unconditional cash transfer + + align:start position:0% +with unconditional cash transfer + + + align:start position:0% +with unconditional cash transfer +possibly a little more effective + + align:start position:0% +possibly a little more effective + + + align:start position:0% +possibly a little more effective +actually that the conditional cash + + align:start position:0% +actually that the conditional cash + + + align:start position:0% +actually that the conditional cash +transfer + + align:start position:0% +transfer + + + align:start position:0% +transfer +so again that's kind of mixed while + + align:start position:0% +so again that's kind of mixed while + + + align:start position:0% +so again that's kind of mixed while +people respond to things that are meant + + align:start position:0% +people respond to things that are meant + + + align:start position:0% +people respond to things that are meant +to send them to school maybe meant to + + align:start position:0% +to send them to school maybe meant to + + + align:start position:0% +to send them to school maybe meant to +reduce the the cost but they seem to do + + align:start position:0% +reduce the the cost but they seem to do + + + align:start position:0% +reduce the the cost but they seem to do +that even though + + align:start position:0% +that even though + + + align:start position:0% +that even though +the transfer is not directly affected to + + align:start position:0% +the transfer is not directly affected to + + + align:start position:0% +the transfer is not directly affected to +the cost + + align:start position:0% +the cost + + + align:start position:0% +the cost +and then of course there is another form + + align:start position:0% +and then of course there is another form + + + align:start position:0% +and then of course there is another form +of indirect indirect reducing the + + align:start position:0% +of indirect indirect reducing the + + + align:start position:0% +of indirect indirect reducing the +indirect cost is is reducing the + + align:start position:0% +indirect cost is is reducing the + + + align:start position:0% +indirect cost is is reducing the +distance to school + + align:start position:0% +distance to school + + + align:start position:0% +distance to school +so someone asked you know how do you + + align:start position:0% +so someone asked you know how do you + + + align:start position:0% +so someone asked you know how do you +think about this intervention the school + + align:start position:0% +think about this intervention the school + + + align:start position:0% +think about this intervention the school +construction intervention and one very + + align:start position:0% +construction intervention and one very + + + align:start position:0% +construction intervention and one very +natural way to think about is you reduce + + align:start position:0% +natural way to think about is you reduce + + + align:start position:0% +natural way to think about is you reduce +the cost of going to school by making + + align:start position:0% +the cost of going to school by making + + + align:start position:0% +the cost of going to school by making +the school very nearby so it's much + + align:start position:0% +the school very nearby so it's much + + + align:start position:0% +the school very nearby so it's much +easier to to go there for the child and + + align:start position:0% +easier to to go there for the child and + + + align:start position:0% +easier to to go there for the child and +for the parents + + align:start position:0% +for the parents + + + align:start position:0% +for the parents +uh so that's that's the that's the idea + + align:start position:0% +uh so that's that's the that's the idea + + + align:start position:0% +uh so that's that's the that's the idea +of of the of my paper on Indonesia so + + align:start position:0% +of of the of my paper on Indonesia so + + + align:start position:0% +of of the of my paper on Indonesia so +someone asked how I came up about uh + + align:start position:0% +someone asked how I came up about uh + + + align:start position:0% +someone asked how I came up about uh +with with this idea + + align:start position:0% +with with this idea + + + align:start position:0% +with with this idea +um so maybe that's relevant second years + + align:start position:0% +um so maybe that's relevant second years + + + align:start position:0% +um so maybe that's relevant second years +I've already had said me that because I + + align:start position:0% +I've already had said me that because I + + + align:start position:0% +I've already had said me that because I +I mentioned it in the in the paper + + align:start position:0% +I mentioned it in the in the paper + + + align:start position:0% +I mentioned it in the in the paper +writing class but that turned out to be + + align:start position:0% +writing class but that turned out to be + + + align:start position:0% +writing class but that turned out to be +my job market paper although I didn't + + align:start position:0% +my job market paper although I didn't + + + align:start position:0% +my job market paper although I didn't +know it was going to be my job market + + align:start position:0% +know it was going to be my job market + + + align:start position:0% +know it was going to be my job market +paper + + align:start position:0% +paper + + + align:start position:0% +paper +uh but I was sitting in development and + + align:start position:0% +uh but I was sitting in development and + + + align:start position:0% +uh but I was sitting in development and +ending in labor and in labor we only + + align:start position:0% +ending in labor and in labor we only + + + align:start position:0% +ending in labor and in labor we only +talked about instrumenting for education + + align:start position:0% +talked about instrumenting for education + + + align:start position:0% +talked about instrumenting for education +and saying it's so important to + + align:start position:0% +and saying it's so important to + + + align:start position:0% +and saying it's so important to +instrument for Education because there + + align:start position:0% +instrument for Education because there + + + align:start position:0% +instrument for Education because there +might be ability by us people who are + + align:start position:0% +might be ability by us people who are + + + align:start position:0% +might be ability by us people who are +more likely to to go to school are also + + align:start position:0% +more likely to to go to school are also + + + align:start position:0% +more likely to to go to school are also +maybe more competent in various ways and + + align:start position:0% +maybe more competent in various ways and + + + align:start position:0% +maybe more competent in various ways and +therefore they'll earn more money anyway + + align:start position:0% +therefore they'll earn more money anyway + + + align:start position:0% +therefore they'll earn more money anyway +even if they don't go to school right so + + align:start position:0% +even if they don't go to school right so + + + align:start position:0% +even if they don't go to school right so +that's the ability bias + + align:start position:0% +that's the ability bias + + + align:start position:0% +that's the ability bias +I thought well in development that seems + + align:start position:0% +I thought well in development that seems + + + align:start position:0% +I thought well in development that seems +worse because it's not just your ability + + align:start position:0% +worse because it's not just your ability + + + align:start position:0% +worse because it's not just your ability +best that in fact we doesn't seem to + + align:start position:0% +best that in fact we doesn't seem to + + + align:start position:0% +best that in fact we doesn't seem to +really be there in rich countries + + align:start position:0% +really be there in rich countries + + + align:start position:0% +really be there in rich countries +you don't seem to have uh + + align:start position:0% +you don't seem to have uh + + + align:start position:0% +you don't seem to have uh +to change the return to education much + + align:start position:0% +to change the return to education much + + + align:start position:0% +to change the return to education much +when you control for this election best + + align:start position:0% +when you control for this election best + + + align:start position:0% +when you control for this election best +but I thought probably in development + + align:start position:0% +but I thought probably in development + + + align:start position:0% +but I thought probably in development +things would be quite different because + + align:start position:0% +things would be quite different because + + + align:start position:0% +things would be quite different because +there are many reasons why kids would go + + align:start position:0% +there are many reasons why kids would go + + + align:start position:0% +there are many reasons why kids would go +to school like in particular the + + align:start position:0% +to school like in particular the + + + align:start position:0% +to school like in particular the +connections of their parents the money + + align:start position:0% +connections of their parents the money + + + align:start position:0% +connections of their parents the money +of their parents that might be related + + align:start position:0% +of their parents that might be related + + + align:start position:0% +of their parents that might be related +with someone's ability to uh to get a + + align:start position:0% +with someone's ability to uh to get a + + + align:start position:0% +with someone's ability to uh to get a +job later + + align:start position:0% +job later + + + align:start position:0% +job later +so I thought the ability bias would have + + align:start position:0% +so I thought the ability bias would have + + + align:start position:0% +so I thought the ability bias would have +to be larger + + align:start position:0% + + + + align:start position:0% + +and then I was very surprised that there + + align:start position:0% +and then I was very surprised that there + + + align:start position:0% +and then I was very surprised that there +was no study using instrumental viable + + align:start position:0% +was no study using instrumental viable + + + align:start position:0% +was no study using instrumental viable +in development + + align:start position:0% +in development + + + align:start position:0% +in development +so I thought someone should hide to + + align:start position:0% +so I thought someone should hide to + + + align:start position:0% +so I thought someone should hide to +study and I was trying to think about + + align:start position:0% +study and I was trying to think about + + + align:start position:0% +study and I was trying to think about +what would be a good instrument and + + align:start position:0% +what would be a good instrument and + + + align:start position:0% +what would be a good instrument and +thinking about distance to school being + + align:start position:0% +thinking about distance to school being + + + align:start position:0% +thinking about distance to school being +a good instrument + + align:start position:0% +a good instrument + + + align:start position:0% +a good instrument +but then thinking well that's not going + + align:start position:0% +but then thinking well that's not going + + + align:start position:0% +but then thinking well that's not going +to work because if people are closer to + + align:start position:0% +to work because if people are closer to + + + align:start position:0% +to work because if people are closer to +school I probably are in more urban + + align:start position:0% +school I probably are in more urban + + + align:start position:0% +school I probably are in more urban +setting + + align:start position:0% +setting + + + align:start position:0% +setting +to what you really need is a change in + + align:start position:0% +to what you really need is a change in + + + align:start position:0% +to what you really need is a change in +the distance to school + + align:start position:0% +the distance to school + + + align:start position:0% +the distance to school +well where would that come from + + align:start position:0% +well where would that come from + + + align:start position:0% +well where would that come from +well if a country started building a lot + + align:start position:0% +well if a country started building a lot + + + align:start position:0% +well if a country started building a lot +of schools that would reduce the + + align:start position:0% +of schools that would reduce the + + + align:start position:0% +of schools that would reduce the +distance to school + + align:start position:0% +distance to school + + + align:start position:0% +distance to school +is there a country that has built a lot + + align:start position:0% +is there a country that has built a lot + + + align:start position:0% +is there a country that has built a lot +of schools + + align:start position:0% +of schools + + + align:start position:0% +of schools +and so I in the back of my mind I was + + align:start position:0% +and so I in the back of my mind I was + + + align:start position:0% +and so I in the back of my mind I was +looking for that country which had built + + align:start position:0% +looking for that country which had built + + + align:start position:0% +looking for that country which had built +a lot of schools now separately we had + + align:start position:0% +a lot of schools now separately we had + + + align:start position:0% +a lot of schools now separately we had +at the time we didn't have a second year + + align:start position:0% +at the time we didn't have a second year + + + align:start position:0% +at the time we didn't have a second year +people but we had to write an + + align:start position:0% +people but we had to write an + + + align:start position:0% +people but we had to write an +econometrics paper and I had written my + + align:start position:0% +econometrics paper and I had written my + + + align:start position:0% +econometrics paper and I had written my +own Indonesia because there was a good + + align:start position:0% +own Indonesia because there was a good + + + align:start position:0% +own Indonesia because there was a good +data set that a lot of people used to do + + align:start position:0% +data set that a lot of people used to do + + + align:start position:0% +data set that a lot of people used to do +any number of things called the + + align:start position:0% +any number of things called the + + + align:start position:0% +any number of things called the +Indonesia Family Life survey + + align:start position:0% +Indonesia Family Life survey + + + align:start position:0% +Indonesia Family Life survey +so kind of kind of started with + + align:start position:0% +so kind of kind of started with + + + align:start position:0% +so kind of kind of started with +Indonesia and I went to the library and + + align:start position:0% +Indonesia and I went to the library and + + + align:start position:0% +Indonesia and I went to the library and +they have all the World Bank reports one + + align:start position:0% +they have all the World Bank reports one + + + align:start position:0% +they have all the World Bank reports one +of you found this report that I found + + align:start position:0% +of you found this report that I found + + + align:start position:0% +of you found this report that I found +1989 report that but they have a bunch + + align:start position:0% +1989 report that but they have a bunch + + + align:start position:0% +1989 report that but they have a bunch +on all of the countries and what they + + align:start position:0% +on all of the countries and what they + + + align:start position:0% +on all of the countries and what they +are doing every year and I thought let + + align:start position:0% +are doing every year and I thought let + + + align:start position:0% +are doing every year and I thought let +me start with Indonesia since there is + + align:start position:0% +me start with Indonesia since there is + + + align:start position:0% +me start with Indonesia since there is +this data set we already know + + align:start position:0% +this data set we already know + + + align:start position:0% +this data set we already know +and then I uh I found that + + align:start position:0% +and then I uh I found that + + + align:start position:0% +and then I uh I found that +I said that's great that's a lot of + + align:start position:0% +I said that's great that's a lot of + + + align:start position:0% +I said that's great that's a lot of +schools that should reduce the number of + + align:start position:0% +schools that should reduce the number of + + + align:start position:0% +schools that should reduce the number of +of schools a lot so let me uh let me see + + align:start position:0% +of schools a lot so let me uh let me see + + + align:start position:0% +of schools a lot so let me uh let me see +whether I can do something uh with that + + align:start position:0% +whether I can do something uh with that + + + align:start position:0% +whether I can do something uh with that +and then I quickly realized that so + + align:start position:0% +and then I quickly realized that so + + + align:start position:0% +and then I quickly realized that so +first of all I had to fund a number of + + align:start position:0% +first of all I had to fund a number of + + + align:start position:0% +first of all I had to fund a number of +schools + + align:start position:0% +schools + + + align:start position:0% +schools +and I had to find a large data set + + align:start position:0% +and I had to find a large data set + + + align:start position:0% +and I had to find a large data set +I figured that such loves it as it + + align:start position:0% +I figured that such loves it as it + + + align:start position:0% +I figured that such loves it as it +exists + + align:start position:0% +exists + + + align:start position:0% +exists +maybe from that same report that they + + align:start position:0% +maybe from that same report that they + + + align:start position:0% +maybe from that same report that they +were using it this kind of large census + + align:start position:0% +were using it this kind of large census + + + align:start position:0% +were using it this kind of large census +and intercances survey so I knew that + + align:start position:0% +and intercances survey so I knew that + + + align:start position:0% +and intercances survey so I knew that +this data set existed I didn't know + + align:start position:0% +this data set existed I didn't know + + + align:start position:0% +this data set existed I didn't know +that the number the data on the number + + align:start position:0% +that the number the data on the number + + + align:start position:0% +that the number the data on the number +of school existed + + align:start position:0% +of school existed + + + align:start position:0% +of school existed +but I thought probably it somewhere has + + align:start position:0% +but I thought probably it somewhere has + + + align:start position:0% +but I thought probably it somewhere has +to be in some library in Indonesia + + align:start position:0% +to be in some library in Indonesia + + + align:start position:0% +to be in some library in Indonesia +so I went to Indonesia + + align:start position:0% +so I went to Indonesia + + + align:start position:0% +so I went to Indonesia +during the summer + + align:start position:0% +during the summer + + + align:start position:0% +during the summer +and I + + align:start position:0% +and I + + + align:start position:0% +and I +hunted for the data which I knew existed + + align:start position:0% +hunted for the data which I knew existed + + + align:start position:0% +hunted for the data which I knew existed +that's the outcome leader I had to go to + + align:start position:0% +that's the outcome leader I had to go to + + + align:start position:0% +that's the outcome leader I had to go to +the statistical office to find it + + align:start position:0% +the statistical office to find it + + + align:start position:0% +the statistical office to find it +um + + align:start position:0% +um + + + align:start position:0% +um +I think you know I so I I know I paid + + align:start position:0% +I think you know I so I I know I paid + + + align:start position:0% +I think you know I so I I know I paid +some money to someone and they gave me + + align:start position:0% +some money to someone and they gave me + + + align:start position:0% +some money to someone and they gave me +the data and I + + align:start position:0% +the data and I + + + align:start position:0% +the data and I +and I didn't poop too much like + + align:start position:0% +and I didn't poop too much like + + + align:start position:0% +and I didn't poop too much like +but that happened now it's much easier + + align:start position:0% +but that happened now it's much easier + + + align:start position:0% +but that happened now it's much easier +the data since then the data from + + align:start position:0% +the data since then the data from + + + align:start position:0% +the data since then the data from +Indonesia is very very easily available + + align:start position:0% +Indonesia is very very easily available + + + align:start position:0% +Indonesia is very very easily available +uh + + align:start position:0% +uh + + + align:start position:0% +uh +Australian National agency front gave + + align:start position:0% +Australian National agency front gave + + + align:start position:0% +Australian National agency front gave +them a lot of detail to make their data + + align:start position:0% +them a lot of detail to make their data + + + align:start position:0% +them a lot of detail to make their data +available + + align:start position:0% +available + + + align:start position:0% +available +and then I went to the library I knew + + align:start position:0% +and then I went to the library I knew + + + align:start position:0% +and then I went to the library I knew +who had implemented this program there + + align:start position:0% +who had implemented this program there + + + align:start position:0% +who had implemented this program there +was a plan the planning department I + + align:start position:0% +was a plan the planning department I + + + align:start position:0% +was a plan the planning department I +went to the library of the planning + + align:start position:0% +went to the library of the planning + + + align:start position:0% +went to the library of the planning +department I asked them would you have + + align:start position:0% +department I asked them would you have + + + align:start position:0% +department I asked them would you have +just did and they gave me like books + + align:start position:0% +just did and they gave me like books + + + align:start position:0% +just did and they gave me like books +which showed the number of the number of + + align:start position:0% +which showed the number of the number of + + + align:start position:0% +which showed the number of the number of +schools that were built in the year the + + align:start position:0% +schools that were built in the year the + + + align:start position:0% +schools that were built in the year the +the plan of the schools Etc + + align:start position:0% +the plan of the schools Etc + + + align:start position:0% +the plan of the schools Etc +I made some photocopier and I was done + + align:start position:0% +I made some photocopier and I was done + + + align:start position:0% +I made some photocopier and I was done +and then I had two more weeks to spend + + align:start position:0% +and then I had two more weeks to spend + + + align:start position:0% +and then I had two more weeks to spend +Indonesia and I got very bored that was + + align:start position:0% +Indonesia and I got very bored that was + + + align:start position:0% +Indonesia and I got very bored that was +the uh the the end of that so that's how + + align:start position:0% +the uh the the end of that so that's how + + + align:start position:0% +the uh the the end of that so that's how +I came to to that everything lined up + + align:start position:0% +I came to to that everything lined up + + + align:start position:0% +I came to to that everything lined up +quite nicely it doesn't have you know + + align:start position:0% +quite nicely it doesn't have you know + + + align:start position:0% +quite nicely it doesn't have you know +it's not always + + align:start position:0% +it's not always + + + align:start position:0% +it's not always +um like that you know there is any + + align:start position:0% +um like that you know there is any + + + align:start position:0% +um like that you know there is any +number of places where this project + + align:start position:0% +number of places where this project + + + align:start position:0% +number of places where this project +could have collapsed but in this + + align:start position:0% +could have collapsed but in this + + + align:start position:0% +could have collapsed but in this +instance like I was lucky at every step + + align:start position:0% +instance like I was lucky at every step + + + align:start position:0% +instance like I was lucky at every step +interestingly I was initially interested + + align:start position:0% +interestingly I was initially interested + + + align:start position:0% +interestingly I was initially interested +um + + align:start position:0% +um + + + align:start position:0% +um +so I had no idea how good an idea it was + + align:start position:0% +so I had no idea how good an idea it was + + + align:start position:0% +so I had no idea how good an idea it was +I just so you know this is I was I gave + + align:start position:0% +I just so you know this is I was I gave + + + align:start position:0% +I just so you know this is I was I gave +this advice to someone yesterday and I + + align:start position:0% +this advice to someone yesterday and I + + + align:start position:0% +this advice to someone yesterday and I +think it's good advice that + + align:start position:0% +think it's good advice that + + + align:start position:0% +think it's good advice that +it's very hard when you start working on + + align:start position:0% +it's very hard when you start working on + + + align:start position:0% +it's very hard when you start working on +on a research project to think about + + align:start position:0% +on a research project to think about + + + align:start position:0% +on a research project to think about +whether that's gonna be a A plus + + align:start position:0% +whether that's gonna be a A plus + + + align:start position:0% +whether that's gonna be a A plus +contribution or a B minus contribution + + align:start position:0% +contribution or a B minus contribution + + + align:start position:0% +contribution or a B minus contribution +or no contribution at all uh it's hard + + align:start position:0% +or no contribution at all uh it's hard + + + align:start position:0% +or no contribution at all uh it's hard +for you and it's even hard for people to + + align:start position:0% +for you and it's even hard for people to + + + align:start position:0% +for you and it's even hard for people to +talk to you + + align:start position:0% +talk to you + + + align:start position:0% +talk to you +so I think the best guy that I have + + align:start position:0% +so I think the best guy that I have + + + align:start position:0% +so I think the best guy that I have +found is to hide the people that I wish + + align:start position:0% +found is to hide the people that I wish + + + align:start position:0% +found is to hide the people that I wish +I had read I want to write the people + + align:start position:0% +I had read I want to write the people + + + align:start position:0% +I had read I want to write the people +that I wish to read + + align:start position:0% +that I wish to read + + + align:start position:0% +that I wish to read +and then you know that at least one + + align:start position:0% +and then you know that at least one + + + align:start position:0% +and then you know that at least one +person will like it and a pretty + + align:start position:0% +person will like it and a pretty + + + align:start position:0% +person will like it and a pretty +important person because that's yourself + + align:start position:0% +important person because that's yourself + + + align:start position:0% +important person because that's yourself +and you're going to spend a lot of time + + align:start position:0% +and you're going to spend a lot of time + + + align:start position:0% +and you're going to spend a lot of time +with that paper and the rest sort of + + align:start position:0% +with that paper and the rest sort of + + + align:start position:0% +with that paper and the rest sort of +walks itself out and I just had no idea + + align:start position:0% +walks itself out and I just had no idea + + + align:start position:0% +walks itself out and I just had no idea +that in and of itself doing all of this + + align:start position:0% +that in and of itself doing all of this + + + align:start position:0% +that in and of itself doing all of this +step was so key it seemed to me very + + align:start position:0% +step was so key it seemed to me very + + + align:start position:0% +step was so key it seemed to me very +easy I thought of it as a + + align:start position:0% +easy I thought of it as a + + + align:start position:0% +easy I thought of it as a +scales like doing skills to take a + + align:start position:0% +scales like doing skills to take a + + + align:start position:0% +scales like doing skills to take a +strategy that is very very well + + align:start position:0% +strategy that is very very well + + + align:start position:0% +strategy that is very very well +established somewhere and transpose it + + align:start position:0% +established somewhere and transpose it + + + align:start position:0% +established somewhere and transpose it +to another context + + align:start position:0% +to another context + + + align:start position:0% +to another context +and in fact in my mind it would it was + + align:start position:0% +and in fact in my mind it would it was + + + align:start position:0% +and in fact in my mind it would it was +gonna help me think about non-parametric + + align:start position:0% +gonna help me think about non-parametric + + + align:start position:0% +gonna help me think about non-parametric +returns to education I had read a paper + + align:start position:0% +returns to education I had read a paper + + + align:start position:0% +returns to education I had read a paper +which was very uh new at the time by + + align:start position:0% +which was very uh new at the time by + + + align:start position:0% +which was very uh new at the time by +Whitney newey about + + align:start position:0% +Whitney newey about + + + align:start position:0% +Whitney newey about +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +estimating non-parametric + + align:start position:0% +estimating non-parametric + + + align:start position:0% +estimating non-parametric +system with triangular + + align:start position:0% +system with triangular + + + align:start position:0% +system with triangular +with this type of situation where you + + align:start position:0% +with this type of situation where you + + + align:start position:0% +with this type of situation where you +have an instrument for for the + + align:start position:0% +have an instrument for for the + + + align:start position:0% +have an instrument for for the +environment so I thought that's where + + align:start position:0% +environment so I thought that's where + + + align:start position:0% +environment so I thought that's where +I'm going to get and at least that's + + align:start position:0% +I'm going to get and at least that's + + + align:start position:0% +I'm going to get and at least that's +going to be something new now it turned + + align:start position:0% +going to be something new now it turned + + + align:start position:0% +going to be something new now it turned +out + + align:start position:0% +out + + + align:start position:0% +out +for reason we're going to discussed very + + align:start position:0% +for reason we're going to discussed very + + + align:start position:0% +for reason we're going to discussed very +soon or if not today or on Monday that + + align:start position:0% +soon or if not today or on Monday that + + + align:start position:0% +soon or if not today or on Monday that +it was completely inappropriate to do + + align:start position:0% +it was completely inappropriate to do + + + align:start position:0% +it was completely inappropriate to do +that + + align:start position:0% +that + + + align:start position:0% +that +and I not only that but I could have + + align:start position:0% +and I not only that but I could have + + + align:start position:0% +and I not only that but I could have +entreated it from the beginning that if + + align:start position:0% +entreated it from the beginning that if + + + align:start position:0% +entreated it from the beginning that if +I had an instrument that affected people + + align:start position:0% +I had an instrument that affected people + + + align:start position:0% +I had an instrument that affected people +going to Primary School I was not going + + align:start position:0% +going to Primary School I was not going + + + align:start position:0% +going to Primary School I was not going +to be able to use it to us to to + + align:start position:0% +to be able to use it to us to to + + + align:start position:0% +to be able to use it to us to to +extrapolate to the entire distribution + + align:start position:0% +extrapolate to the entire distribution + + + align:start position:0% +extrapolate to the entire distribution +of the returns across the entire + + align:start position:0% +of the returns across the entire + + + align:start position:0% +of the returns across the entire +education Spectrum so I had thought + + align:start position:0% +education Spectrum so I had thought + + + align:start position:0% +education Spectrum so I had thought +about it I would have realized this was + + align:start position:0% +about it I would have realized this was + + + align:start position:0% +about it I would have realized this was +not this part of the project couldn't + + align:start position:0% +not this part of the project couldn't + + + align:start position:0% +not this part of the project couldn't +get done but it turned out that even + + align:start position:0% +get done but it turned out that even + + + align:start position:0% +get done but it turned out that even +without this part of the project that + + align:start position:0% +without this part of the project that + + + align:start position:0% +without this part of the project that +that was a good paper or at least a + + align:start position:0% +that was a good paper or at least a + + + align:start position:0% +that was a good paper or at least a +um understood to be a good people or got + + align:start position:0% +um understood to be a good people or got + + + align:start position:0% +um understood to be a good people or got +me a job and and so on and so forth uh + + align:start position:0% +me a job and and so on and so forth uh + + + align:start position:0% +me a job and and so on and so forth uh +so I'd like to say that it's hard to + + align:start position:0% +so I'd like to say that it's hard to + + + align:start position:0% +so I'd like to say that it's hard to +you know + + align:start position:0% +you know + + + align:start position:0% +you know +it's kind of it was a nice project + + align:start position:0% +it's kind of it was a nice project + + + align:start position:0% +it's kind of it was a nice project +because + + align:start position:0% +because + + + align:start position:0% +because +the steps were so clear + + align:start position:0% +the steps were so clear + + + align:start position:0% +the steps were so clear +to me and then you know I was lucky to + + align:start position:0% +to me and then you know I was lucky to + + + align:start position:0% +to me and then you know I was lucky to +get them done I was not stopped by the + + align:start position:0% +get them done I was not stopped by the + + + align:start position:0% +get them done I was not stopped by the +fact that I didn't know if I would find + + align:start position:0% +fact that I didn't know if I would find + + + align:start position:0% +fact that I didn't know if I would find +the data I would take some risk and then + + align:start position:0% +the data I would take some risk and then + + + align:start position:0% +the data I would take some risk and then +uh + + align:start position:0% +uh + + + align:start position:0% +uh +even though the steps we have to clear + + align:start position:0% +even though the steps we have to clear + + + align:start position:0% +even though the steps we have to clear +it was simple at the time it was + + align:start position:0% +it was simple at the time it was + + + align:start position:0% +it was simple at the time it was +sufficient now of course everything + + align:start position:0% +sufficient now of course everything + + + align:start position:0% +sufficient now of course everything +needs to have more bells and results but + + align:start position:0% +needs to have more bells and results but + + + align:start position:0% +needs to have more bells and results but +um + + align:start position:0% +um + + + align:start position:0% +um +I think the general principle of not + + align:start position:0% +I think the general principle of not + + + align:start position:0% +I think the general principle of not +being + + align:start position:0% +being + + + align:start position:0% +being +discouraged in advanced but this is too + + align:start position:0% +discouraged in advanced but this is too + + + align:start position:0% +discouraged in advanced but this is too +easy or this is too obvious still hold + + align:start position:0% +easy or this is too obvious still hold + + + align:start position:0% +easy or this is too obvious still hold +so that's for the autobiography of + + align:start position:0% +so that's for the autobiography of + + + align:start position:0% +so that's for the autobiography of +related to this paper + + align:start position:0% +related to this paper + + + align:start position:0% +related to this paper +so it's a difference in difference we + + align:start position:0% +so it's a difference in difference we + + + align:start position:0% +so it's a difference in difference we +are going to see a lot of that you are + + align:start position:0% +are going to see a lot of that you are + + + align:start position:0% +are going to see a lot of that you are +going to see a lot of that in your + + align:start position:0% +going to see a lot of that in your + + + align:start position:0% +going to see a lot of that in your +career if you're an empirical person at + + align:start position:0% +career if you're an empirical person at + + + align:start position:0% +career if you're an empirical person at +some point you'll probably estimate some + + align:start position:0% +some point you'll probably estimate some + + + align:start position:0% +some point you'll probably estimate some +version of an event study graph or a + + align:start position:0% +version of an event study graph or a + + + align:start position:0% +version of an event study graph or a +different different div + + align:start position:0% +different different div + + + align:start position:0% +different different div +um + + align:start position:0% +um + + + align:start position:0% +um +um it's you know in the simpler setting + + align:start position:0% +um it's you know in the simpler setting + + + align:start position:0% +um it's you know in the simpler setting +it's a pretty straightforward you have + + align:start position:0% +it's a pretty straightforward you have + + + align:start position:0% +it's a pretty straightforward you have +two groups and then two periods + + align:start position:0% + + + + align:start position:0% + +um and then the group gets treated in + + align:start position:0% +um and then the group gets treated in + + + align:start position:0% +um and then the group gets treated in +the post period and not in the + + align:start position:0% +the post period and not in the + + + align:start position:0% +the post period and not in the +pre-period and your identification + + align:start position:0% +pre-period and your identification + + + align:start position:0% +pre-period and your identification +assumption can be written in this way + + align:start position:0% +assumption can be written in this way + + + align:start position:0% +assumption can be written in this way +which is if you think of it in terms of + + align:start position:0% +which is if you think of it in terms of + + + align:start position:0% +which is if you think of it in terms of +your potential outcome untreated + + align:start position:0% +your potential outcome untreated + + + align:start position:0% +your potential outcome untreated +uh it's a function possibly you know + + align:start position:0% +uh it's a function possibly you know + + + align:start position:0% +uh it's a function possibly you know +very flexible function where of You Know + + align:start position:0% +very flexible function where of You Know + + + align:start position:0% +very flexible function where of You Know +Anything could happen with respect to + + align:start position:0% +Anything could happen with respect to + + + align:start position:0% +Anything could happen with respect to +the group + + align:start position:0% +the group + + + align:start position:0% +the group +it could be related to the to the group + + align:start position:0% +it could be related to the to the group + + + align:start position:0% +it could be related to the to the group +to the time period but but what's not + + align:start position:0% +to the time period but but what's not + + + align:start position:0% +to the time period but but what's not +there that's going to help you for + + align:start position:0% +there that's going to help you for + + + align:start position:0% +there that's going to help you for +identification help us for + + align:start position:0% +identification help us for + + + align:start position:0% +identification help us for +identification + + align:start position:0% + + + + align:start position:0% + +what did I purposefully you meet from + + align:start position:0% +what did I purposefully you meet from + + + align:start position:0% +what did I purposefully you meet from +this + + align:start position:0% +this + + + align:start position:0% +this +equation that determines yes the + + align:start position:0% +equation that determines yes the + + + align:start position:0% +equation that determines yes the +interaction between belonging to the + + align:start position:0% +interaction between belonging to the + + + align:start position:0% +interaction between belonging to the +group and exactly so we assume that uh + + align:start position:0% +group and exactly so we assume that uh + + + align:start position:0% +group and exactly so we assume that uh +you know maybe people who are younger + + align:start position:0% +you know maybe people who are younger + + + align:start position:0% +you know maybe people who are younger +will get more education because they are + + align:start position:0% +will get more education because they are + + + align:start position:0% +will get more education because they are +younger countries is richer + + align:start position:0% +younger countries is richer + + + align:start position:0% +younger countries is richer +people who are in some region will get + + align:start position:0% +people who are in some region will get + + + align:start position:0% +people who are in some region will get +more education than others but there is + + align:start position:0% +more education than others but there is + + + align:start position:0% +more education than others but there is +no the younger people in the place that + + align:start position:0% +no the younger people in the place that + + + align:start position:0% +no the younger people in the place that +are more educated would not otherwise + + align:start position:0% +are more educated would not otherwise + + + align:start position:0% +are more educated would not otherwise +have been even more even less + + align:start position:0% +have been even more even less + + + align:start position:0% +have been even more even less +so that's the Assumption we're making + + align:start position:0% +so that's the Assumption we're making + + + align:start position:0% +so that's the Assumption we're making +and that's the key identification + + align:start position:0% +and that's the key identification + + + align:start position:0% +and that's the key identification +assumption and in a lot of difference in + + align:start position:0% +assumption and in a lot of difference in + + + align:start position:0% +assumption and in a lot of difference in +different application + + align:start position:0% +different application + + + align:start position:0% +different application +the trick is going to uh both justify + + align:start position:0% +the trick is going to uh both justify + + + align:start position:0% +the trick is going to uh both justify +this assumption from a priori principle + + align:start position:0% +this assumption from a priori principle + + + align:start position:0% +this assumption from a priori principle +and kind of gather as much evidence as + + align:start position:0% +and kind of gather as much evidence as + + + align:start position:0% +and kind of gather as much evidence as +possible at the assumption is in fact + + align:start position:0% +possible at the assumption is in fact + + + align:start position:0% +possible at the assumption is in fact +real + + align:start position:0% +real + + + align:start position:0% +real +once we have that then we are in good + + align:start position:0% +once we have that then we are in good + + + align:start position:0% +once we have that then we are in good +shape so if if again if we have two + + align:start position:0% +shape so if if again if we have two + + + align:start position:0% +shape so if if again if we have two +groups to period + + align:start position:0% +groups to period + + + align:start position:0% +groups to period +then the different deep estimator is + + align:start position:0% +then the different deep estimator is + + + align:start position:0% +then the different deep estimator is +simply out of the object that we are + + align:start position:0% +simply out of the object that we are + + + align:start position:0% +simply out of the object that we are +trying to to estimate is the the + + align:start position:0% +trying to to estimate is the the + + + align:start position:0% +trying to to estimate is the the +difference in mean uh + + align:start position:0% +difference in mean uh + + + align:start position:0% +difference in mean uh +between pre and post and pre for the + + align:start position:0% +between pre and post and pre for the + + + align:start position:0% +between pre and post and pre for the +treated group minus the same thing for + + align:start position:0% +treated group minus the same thing for + + + align:start position:0% +treated group minus the same thing for +the control group and add the + + align:start position:0% +the control group and add the + + + align:start position:0% +the control group and add the +identification assumption that I laid + + align:start position:0% +identification assumption that I laid + + + align:start position:0% +identification assumption that I laid +down that's going to give you uh the the + + align:start position:0% +down that's going to give you uh the the + + + align:start position:0% +down that's going to give you uh the the +impact the average impact of the program + + align:start position:0% +impact the average impact of the program + + + align:start position:0% +impact the average impact of the program +of course we don't have this thing so we + + align:start position:0% +of course we don't have this thing so we + + + align:start position:0% +of course we don't have this thing so we +will place them by population averages + + align:start position:0% +will place them by population averages + + + align:start position:0% +will place them by population averages +uh in in our or by sample averages + + align:start position:0% +uh in in our or by sample averages + + + align:start position:0% +uh in in our or by sample averages +and uh the the different estimator is + + align:start position:0% +and uh the the different estimator is + + + align:start position:0% +and uh the the different estimator is +now going to be used to be had there is + + align:start position:0% +now going to be used to be had there is + + + align:start position:0% +now going to be used to be had there is +going to be the average uh treated + + align:start position:0% +going to be the average uh treated + + + align:start position:0% +going to be the average uh treated +treated compost minus treated good P + + align:start position:0% +treated compost minus treated good P + + + align:start position:0% +treated compost minus treated good P +minus control code post minus control + + align:start position:0% +minus control code post minus control + + + align:start position:0% +minus control code post minus control +group + + align:start position:0% + + + + align:start position:0% + +I would like you to uh to do three lines + + align:start position:0% +I would like you to uh to do three lines + + + align:start position:0% +I would like you to uh to do three lines +of algebra when you go home ah + + align:start position:0% +of algebra when you go home ah + + + align:start position:0% +of algebra when you go home ah +which will convince you that + + align:start position:0% +which will convince you that + + + align:start position:0% +which will convince you that +this uh and this is numerically + + align:start position:0% +this uh and this is numerically + + + align:start position:0% +this uh and this is numerically +equivalent + + align:start position:0% +equivalent + + + align:start position:0% +equivalent +to estimating an OLS regression + + align:start position:0% +to estimating an OLS regression + + + align:start position:0% +to estimating an OLS regression +on a group a treated dummy a constant + + align:start position:0% +on a group a treated dummy a constant + + + align:start position:0% +on a group a treated dummy a constant +treated dummy + + align:start position:0% +treated dummy + + + align:start position:0% +treated dummy +a post dummy and the interaction of the + + align:start position:0% +a post dummy and the interaction of the + + + align:start position:0% +a post dummy and the interaction of the +two + + align:start position:0% +two + + + align:start position:0% +two +okay + + align:start position:0% +okay + + + align:start position:0% +okay +with undergraduates I make the + + align:start position:0% +with undergraduates I make the + + + align:start position:0% +with undergraduates I make the +calculations + + align:start position:0% +calculations + + + align:start position:0% +calculations +but I'm going to assume that you can + + align:start position:0% +but I'm going to assume that you can + + + align:start position:0% +but I'm going to assume that you can +make it that's the from the OLS Formula + + align:start position:0% +make it that's the from the OLS Formula + + + align:start position:0% +make it that's the from the OLS Formula +so it takes + + align:start position:0% +so it takes + + + align:start position:0% +so it takes +lines of algebra but it's interesting + + align:start position:0% +lines of algebra but it's interesting + + + align:start position:0% +lines of algebra but it's interesting +it's you know it's good to have in mind + + align:start position:0% +it's you know it's good to have in mind + + + align:start position:0% +it's you know it's good to have in mind +you really need to know and sometimes we + + align:start position:0% +you really need to know and sometimes we + + + align:start position:0% +you really need to know and sometimes we +ask this question in the exam and not + + align:start position:0% +ask this question in the exam and not + + + align:start position:0% +ask this question in the exam and not +everybody gets it uh you really need to + + align:start position:0% +everybody gets it uh you really need to + + + align:start position:0% +everybody gets it uh you really need to +know what this is this is the difference + + align:start position:0% +know what this is this is the difference + + + align:start position:0% +know what this is this is the difference +between + + align:start position:0% + + + + align:start position:0% + +beta1 this is the difference between + + align:start position:0% +beta1 this is the difference between + + + align:start position:0% +beta1 this is the difference between +um treated and controlled in the + + align:start position:0% +um treated and controlled in the + + + align:start position:0% +um treated and controlled in the +pre-period + + align:start position:0% +pre-period + + + align:start position:0% +pre-period +numerically + + align:start position:0% +numerically + + + align:start position:0% +numerically +and this is the difference + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +this is something + + align:start position:0% + + + + align:start position:0% + +one needs to know in life because you + + align:start position:0% +one needs to know in life because you + + + align:start position:0% +one needs to know in life because you +get to + + align:start position:0% +get to + + + align:start position:0% +get to +so in our setting uh + + align:start position:0% +so in our setting uh + + + align:start position:0% +so in our setting uh +we have a relatively Swift School + + align:start position:0% +we have a relatively Swift School + + + align:start position:0% +we have a relatively Swift School +construction building program financed + + align:start position:0% +construction building program financed + + + align:start position:0% +construction building program financed +by the album in 1973 so someone asked + + align:start position:0% +by the album in 1973 so someone asked + + + align:start position:0% +by the album in 1973 so someone asked +how it came about that they decided to + + align:start position:0% +how it came about that they decided to + + + align:start position:0% +how it came about that they decided to +use their oil money to do that what's + + align:start position:0% +use their oil money to do that what's + + + align:start position:0% +use their oil money to do that what's +the political economy of that + + align:start position:0% +the political economy of that + + + align:start position:0% +the political economy of that +so the political economy of that is the + + align:start position:0% +so the political economy of that is the + + + align:start position:0% +so the political economy of that is the +suato came to power after a pretty + + align:start position:0% +suato came to power after a pretty + + + align:start position:0% +suato came to power after a pretty +bloody Civil War + + align:start position:0% +bloody Civil War + + + align:start position:0% +bloody Civil War +millions of Communists were killed uh + + align:start position:0% +millions of Communists were killed uh + + + align:start position:0% +millions of Communists were killed uh +the country was not in good shape + + align:start position:0% +the country was not in good shape + + + align:start position:0% +the country was not in good shape +um either politically economically when + + align:start position:0% +um either politically economically when + + + align:start position:0% +um either politically economically when +he took and Consolidated power + + align:start position:0% +he took and Consolidated power + + + align:start position:0% +he took and Consolidated power +and his view for fixing that was to try + + align:start position:0% +and his view for fixing that was to try + + + align:start position:0% +and his view for fixing that was to try +and create a national identity + + align:start position:0% +and create a national identity + + + align:start position:0% +and create a national identity +which was uniform for the whole country + + align:start position:0% +which was uniform for the whole country + + + align:start position:0% +which was uniform for the whole country +and to do that it sort of invented a + + align:start position:0% +and to do that it sort of invented a + + + align:start position:0% +and to do that it sort of invented a +whole ideology called the pankasilla uh + + align:start position:0% +whole ideology called the pankasilla uh + + + align:start position:0% +whole ideology called the pankasilla uh +really promoted the Bahasa Indonesia + + align:start position:0% +really promoted the Bahasa Indonesia + + + align:start position:0% +really promoted the Bahasa Indonesia +language which interestingly is the + + align:start position:0% +language which interestingly is the + + + align:start position:0% +language which interestingly is the +language of no one in particular it's a + + align:start position:0% +language of no one in particular it's a + + + align:start position:0% +language of no one in particular it's a +group it's a Trader language that's not + + align:start position:0% +group it's a Trader language that's not + + + align:start position:0% +group it's a Trader language that's not +spoken was not spoken in particular by + + align:start position:0% +spoken was not spoken in particular by + + + align:start position:0% +spoken was not spoken in particular by +the main ethnic group and he thought + + align:start position:0% +the main ethnic group and he thought + + + align:start position:0% +the main ethnic group and he thought +schools would be a good way to diffuse + + align:start position:0% +schools would be a good way to diffuse + + + align:start position:0% +schools would be a good way to diffuse +that ideology and to diffuse the + + align:start position:0% +that ideology and to diffuse the + + + align:start position:0% +that ideology and to diffuse the +language and therefore to create a sense + + align:start position:0% +language and therefore to create a sense + + + align:start position:0% +language and therefore to create a sense +of national Unity after what they had + + align:start position:0% +of national Unity after what they had + + + align:start position:0% +of national Unity after what they had +experienced + + align:start position:0% +experienced + + + align:start position:0% +experienced +and before that the Indonesian is an oil + + align:start position:0% +and before that the Indonesian is an oil + + + align:start position:0% +and before that the Indonesian is an oil +producing contribute before that the the + + align:start position:0% +producing contribute before that the the + + + align:start position:0% +producing contribute before that the the +oil proceeds used to go to the places + + align:start position:0% +oil proceeds used to go to the places + + + align:start position:0% +oil proceeds used to go to the places +that produce the oil + + align:start position:0% +that produce the oil + + + align:start position:0% +that produce the oil +and another thing that he thought that + + align:start position:0% +and another thing that he thought that + + + align:start position:0% +and another thing that he thought that +he would consolidate both his power and + + align:start position:0% +he would consolidate both his power and + + + align:start position:0% +he would consolidate both his power and +the whole place was to use this proceed + + align:start position:0% +the whole place was to use this proceed + + + align:start position:0% +the whole place was to use this proceed +in a more Equitable way + + align:start position:0% +in a more Equitable way + + + align:start position:0% +in a more Equitable way +so he decided that all of the money from + + align:start position:0% +so he decided that all of the money from + + + align:start position:0% +so he decided that all of the money from +the oil had to be redistributed by the + + align:start position:0% +the oil had to be redistributed by the + + + align:start position:0% +the oil had to be redistributed by the +center in Social programs + + align:start position:0% +center in Social programs + + + align:start position:0% +center in Social programs +and one of Andy School construction + + align:start position:0% +and one of Andy School construction + + + align:start position:0% +and one of Andy School construction +programs + + align:start position:0% +programs + + + align:start position:0% +programs +impressed in presidential instruction by + + align:start position:0% +impressed in presidential instruction by + + + align:start position:0% +impressed in presidential instruction by +Presidential instruction + + align:start position:0% +Presidential instruction + + + align:start position:0% +Presidential instruction +so the impressed the education the + + align:start position:0% +so the impressed the education the + + + align:start position:0% +so the impressed the education the +primary school program was the first of + + align:start position:0% +primary school program was the first of + + + align:start position:0% +primary school program was the first of +those then there was a water and + + align:start position:0% +those then there was a water and + + + align:start position:0% +those then there was a water and +sanitation program + + align:start position:0% +sanitation program + + + align:start position:0% +sanitation program +so the but when they started it was very + + align:start position:0% +so the but when they started it was very + + + align:start position:0% +so the but when they started it was very +small because they started to the first + + align:start position:0% +small because they started to the first + + + align:start position:0% +small because they started to the first +year of this is was 1972 and then the + + align:start position:0% +year of this is was 1972 and then the + + + align:start position:0% +year of this is was 1972 and then the +oil boom came in and it became I think + + align:start position:0% +oil boom came in and it became I think + + + align:start position:0% +oil boom came in and it became I think +much bigger than what they had + + align:start position:0% +much bigger than what they had + + + align:start position:0% +much bigger than what they had +anticipated + + align:start position:0% +anticipated + + + align:start position:0% +anticipated +and I kind of stuck with it both in + + align:start position:0% +and I kind of stuck with it both in + + + align:start position:0% +and I kind of stuck with it both in +terms of how to allocate the rules how + + align:start position:0% +terms of how to allocate the rules how + + + align:start position:0% +terms of how to allocate the rules how +to allocate the schools and to continue + + align:start position:0% +to allocate the schools and to continue + + + align:start position:0% +to allocate the schools and to continue +using uh our money for to this purpose + + align:start position:0% +using uh our money for to this purpose + + + align:start position:0% +using uh our money for to this purpose +so it's very different to Brazil for + + align:start position:0% +so it's very different to Brazil for + + + align:start position:0% +so it's very different to Brazil for +example where the old money is being + + align:start position:0% +example where the old money is being + + + align:start position:0% +example where the old money is being +spent in the provinces that extracted or + + align:start position:0% +spent in the provinces that extracted or + + + align:start position:0% +spent in the provinces that extracted or +in fact a lot of the oil is in the sea + + align:start position:0% +in fact a lot of the oil is in the sea + + + align:start position:0% +in fact a lot of the oil is in the sea +so it's extracted it's used in the + + align:start position:0% +so it's extracted it's used in the + + + align:start position:0% +so it's extracted it's used in the +provinces that are in line to the Sea + + align:start position:0% +provinces that are in line to the Sea + + + align:start position:0% +provinces that are in line to the Sea +and and that money there is a whole + + align:start position:0% +and and that money there is a whole + + + align:start position:0% +and and that money there is a whole +literature showing that that money is + + align:start position:0% +literature showing that that money is + + + align:start position:0% +literature showing that that money is +not very well spent by those places + + align:start position:0% +not very well spent by those places + + + align:start position:0% +not very well spent by those places +so that's the political economy of that + + align:start position:0% +so that's the political economy of that + + + align:start position:0% +so that's the political economy of that +uh + + align:start position:0% +uh + + + align:start position:0% +uh +then they decided that they were going + + align:start position:0% +then they decided that they were going + + + align:start position:0% +then they decided that they were going +to to allocate the schools because the + + align:start position:0% +to to allocate the schools because the + + + align:start position:0% +to to allocate the schools because the +objective was to get to 85 enrollment + + align:start position:0% +objective was to get to 85 enrollment + + + align:start position:0% +objective was to get to 85 enrollment +everywhere so they were going to + + align:start position:0% +everywhere so they were going to + + + align:start position:0% +everywhere so they were going to +allocate the school as a function of the + + align:start position:0% +allocate the school as a function of the + + + align:start position:0% +allocate the school as a function of the +difference between 85 percent and + + align:start position:0% +difference between 85 percent and + + + align:start position:0% +difference between 85 percent and +wherever the school the place was + + align:start position:0% +wherever the school the place was + + + align:start position:0% +wherever the school the place was +they had their census in 1971 so they + + align:start position:0% +they had their census in 1971 so they + + + align:start position:0% +they had their census in 1971 so they +were using basically use that to say + + align:start position:0% +were using basically use that to say + + + align:start position:0% +were using basically use that to say +to basically linear increase to 85 + + align:start position:0% +to basically linear increase to 85 + + + align:start position:0% +to basically linear increase to 85 +percent and in principally should have + + align:start position:0% +percent and in principally should have + + + align:start position:0% +percent and in principally should have +stuck at 85 percent that's another thing + + align:start position:0% +stuck at 85 percent that's another thing + + + align:start position:0% +stuck at 85 percent that's another thing +that I tried to use and didn't use to + + align:start position:0% +that I tried to use and didn't use to + + + align:start position:0% +that I tried to use and didn't use to +see whether after 85 percent it should + + align:start position:0% +see whether after 85 percent it should + + + align:start position:0% +see whether after 85 percent it should +have flattened and so one could use that + + align:start position:0% +have flattened and so one could use that + + + align:start position:0% +have flattened and so one could use that +for her + + align:start position:0% +for her + + + align:start position:0% +for her +neater identification but it didn't + + align:start position:0% +neater identification but it didn't + + + align:start position:0% +neater identification but it didn't +quite it wasn't it was too smooth so it + + align:start position:0% +quite it wasn't it was too smooth so it + + + align:start position:0% +quite it wasn't it was too smooth so it +didn't work + + align:start position:0% +didn't work + + + align:start position:0% +didn't work +so with that just it depends on the free + + align:start position:0% +so with that just it depends on the free + + + align:start position:0% +so with that just it depends on the free +campaign enrollment that gives me my + + align:start position:0% +campaign enrollment that gives me my + + + align:start position:0% +campaign enrollment that gives me my +difference in difference + + align:start position:0% +difference in difference + + + align:start position:0% +difference in difference +so I'm going to define a group of of + + align:start position:0% +so I'm going to define a group of of + + + align:start position:0% +so I'm going to define a group of of +treated people which are the young guys + + align:start position:0% +treated people which are the young guys + + + align:start position:0% +treated people which are the young guys +and then treated in control region + + align:start position:0% + + + + align:start position:0% + +um to start with we can say well let's + + align:start position:0% +um to start with we can say well let's + + + align:start position:0% +um to start with we can say well let's +say we look above the median + + align:start position:0% +say we look above the median + + + align:start position:0% +say we look above the median +and then we can do a simple definitive + + align:start position:0% +and then we can do a simple definitive + + + align:start position:0% +and then we can do a simple definitive +for year of education so this is these + + align:start position:0% +for year of education so this is these + + + align:start position:0% +for year of education so this is these +are a sample average for the high uh in + + align:start position:0% +are a sample average for the high uh in + + + align:start position:0% +are a sample average for the high uh in +program intensity and the young people + + align:start position:0% +program intensity and the young people + + + align:start position:0% +program intensity and the young people +higher program intensity and the old + + align:start position:0% +higher program intensity and the old + + + align:start position:0% +higher program intensity and the old +people the first thing we notice among + + align:start position:0% +people the first thing we notice among + + + align:start position:0% +people the first thing we notice among +the old people there was a education + + align:start position:0% +the old people there was a education + + + align:start position:0% +the old people there was a education +levels this is years of education + + align:start position:0% +levels this is years of education + + + align:start position:0% +levels this is years of education +attained by adults who were kids during + + align:start position:0% +attained by adults who were kids during + + + align:start position:0% +attained by adults who were kids during +this period is lower in the high + + align:start position:0% +this period is lower in the high + + + align:start position:0% +this period is lower in the high +intensity region that makes sense right + + align:start position:0% +intensity region that makes sense right + + + align:start position:0% +intensity region that makes sense right +because the + + align:start position:0% +because the + + + align:start position:0% +because the +because they were putting more schools + + align:start position:0% +because they were putting more schools + + + align:start position:0% +because they were putting more schools +in places that had less education to + + align:start position:0% +in places that had less education to + + + align:start position:0% +in places that had less education to +start with + + align:start position:0% +start with + + + align:start position:0% +start with +and they are still lower in for the + + align:start position:0% +and they are still lower in for the + + + align:start position:0% +and they are still lower in for the +young kids but less so + + align:start position:0% +young kids but less so + + + align:start position:0% +young kids but less so +so the difference is + + align:start position:0% +so the difference is + + + align:start position:0% +so the difference is +the difference is positive + + align:start position:0% +the difference is positive + + + align:start position:0% +the difference is positive +um although it's you know it's + + align:start position:0% +um although it's you know it's + + + align:start position:0% +um although it's you know it's +insignificant + + align:start position:0% +insignificant + + + align:start position:0% +insignificant +so this is illustrative but it's not + + align:start position:0% +so this is illustrative but it's not + + + align:start position:0% +so this is illustrative but it's not +very precise + + align:start position:0% + + + + align:start position:0% + +so that's that's good so then now we can + + align:start position:0% +so that's that's good so then now we can + + + align:start position:0% +so that's that's good so then now we can +look at uh + + align:start position:0% +look at uh + + + align:start position:0% +look at uh +we can be a bit concerned that in even + + align:start position:0% +we can be a bit concerned that in even + + + align:start position:0% +we can be a bit concerned that in even +in the absence of the program + + align:start position:0% +in the absence of the program + + + align:start position:0% +in the absence of the program +the young cohort would have converted + + align:start position:0% +the young cohort would have converted + + + align:start position:0% +the young cohort would have converted +maybe to the to the old cohorts because + + align:start position:0% +maybe to the to the old cohorts because + + + align:start position:0% +maybe to the to the old cohorts because +my + + align:start position:0% +my + + + align:start position:0% +my +go back to our basic model things + + align:start position:0% +go back to our basic model things + + + align:start position:0% +go back to our basic model things +convert and there should be one steady + + align:start position:0% +convert and there should be one steady + + + align:start position:0% +convert and there should be one steady +state to where everybody is going and + + align:start position:0% +state to where everybody is going and + + + align:start position:0% +state to where everybody is going and +it's within the country so we would + + align:start position:0% +it's within the country so we would + + + align:start position:0% +it's within the country so we would +expect conversions anyway so am I just + + align:start position:0% +expect conversions anyway so am I just + + + align:start position:0% +expect conversions anyway so am I just +capturing that + + align:start position:0% +capturing that + + + align:start position:0% +capturing that +so one easy way to do that is to compare + + align:start position:0% +so one easy way to do that is to compare + + + align:start position:0% +so one easy way to do that is to compare +the old to the very old + + align:start position:0% +the old to the very old + + + align:start position:0% +the old to the very old +um and uh + + align:start position:0% +um and uh + + + align:start position:0% +um and uh +we can do that with that kind of control + + align:start position:0% +we can do that with that kind of control + + + align:start position:0% +we can do that with that kind of control +experiment + + align:start position:0% +experiment + + + align:start position:0% +experiment +and there we can see that at least + + align:start position:0% +and there we can see that at least + + + align:start position:0% +and there we can see that at least +before it seems to be that the trend + + align:start position:0% +before it seems to be that the trend + + + align:start position:0% +before it seems to be that the trend +were in fact parallel between the two + + align:start position:0% +were in fact parallel between the two + + + align:start position:0% +were in fact parallel between the two +places + + align:start position:0% +places + + + align:start position:0% +places +so that's that's uh encouraging the the + + align:start position:0% +so that's that's uh encouraging the the + + + align:start position:0% +so that's that's uh encouraging the the +old and these are already my old and + + align:start position:0% +old and these are already my old and + + + align:start position:0% +old and these are already my old and +this is my very old and if I had done + + align:start position:0% +this is my very old and if I had done + + + align:start position:0% +this is my very old and if I had done +the differently for them I would have + + align:start position:0% +the differently for them I would have + + + align:start position:0% +the differently for them I would have +found a much smaller number + + align:start position:0% +found a much smaller number + + + align:start position:0% +found a much smaller number +and so that's + + align:start position:0% +and so that's + + + align:start position:0% +and so that's +goes in the right direction + + align:start position:0% +goes in the right direction + + + align:start position:0% +goes in the right direction +now this is all this is quite good and + + align:start position:0% +now this is all this is quite good and + + + align:start position:0% +now this is all this is quite good and +we can do better than that and that's + + align:start position:0% +we can do better than that and that's + + + align:start position:0% +we can do better than that and that's +where we have uh you know first of all + + align:start position:0% +where we have uh you know first of all + + + align:start position:0% +where we have uh you know first of all +we have many groups + + align:start position:0% +we have many groups + + + align:start position:0% +we have many groups +uh so in some places they built one + + align:start position:0% +uh so in some places they built one + + + align:start position:0% +uh so in some places they built one +school where thousand kids and two + + align:start position:0% +school where thousand kids and two + + + align:start position:0% +school where thousand kids and two +schools per thousand kids and 100 School + + align:start position:0% +schools per thousand kids and 100 School + + + align:start position:0% +schools per thousand kids and 100 School +per thousand kids or you know it doesn't + + align:start position:0% +per thousand kids or you know it doesn't + + + align:start position:0% +per thousand kids or you know it doesn't +go till 100 but so we could think of + + align:start position:0% +go till 100 but so we could think of + + + align:start position:0% +go till 100 but so we could think of +several treatments + + align:start position:0% +several treatments + + + align:start position:0% +several treatments +so in our in our case you could have one + + align:start position:0% +so in our in our case you could have one + + + align:start position:0% +so in our in our case you could have one +two three if you have not very many or + + align:start position:0% +two three if you have not very many or + + + align:start position:0% +two three if you have not very many or +you could have in our case we can say + + align:start position:0% +you could have in our case we can say + + + align:start position:0% +you could have in our case we can say +this is something discreet + + align:start position:0% +this is something discreet + + + align:start position:0% +this is something discreet +uh and I'm going to replace my uh simple + + align:start position:0% +uh and I'm going to replace my uh simple + + + align:start position:0% +uh and I'm going to replace my uh simple +defend div by by the clear regression + + align:start position:0% +defend div by by the clear regression + + + align:start position:0% +defend div by by the clear regression +uh pre and post on the number of + + align:start position:0% +uh pre and post on the number of + + + align:start position:0% +uh pre and post on the number of +Education differences + + align:start position:0% +Education differences + + + align:start position:0% +Education differences +on the + + align:start position:0% +on the + + + align:start position:0% +on the +um + + align:start position:0% +um + + + align:start position:0% +um +on the number of kids that were built + + align:start position:0% +on the number of kids that were built + + + align:start position:0% +on the number of kids that were built +so again if I had only two cohorts and I + + align:start position:0% +so again if I had only two cohorts and I + + + align:start position:0% +so again if I had only two cohorts and I +only relaxed that it gives me a + + align:start position:0% + + + + align:start position:0% + +I'm now need to control I need to put + + align:start position:0% +I'm now need to control I need to put + + + align:start position:0% +I'm now need to control I need to put +region fixed effect + + align:start position:0% +region fixed effect + + + align:start position:0% +region fixed effect +so that's control for any differences uh + + align:start position:0% +so that's control for any differences uh + + + align:start position:0% +so that's control for any differences uh +and then I'm going to assume here I make + + align:start position:0% +and then I'm going to assume here I make + + + align:start position:0% +and then I'm going to assume here I make +the assumption that the effect is linear + + align:start position:0% +the assumption that the effect is linear + + + align:start position:0% +the assumption that the effect is linear +in a number of school + + align:start position:0% +in a number of school + + + align:start position:0% +in a number of school +uh so I'm + + align:start position:0% + + + + align:start position:0% + +regressing on an interaction not anymore + + align:start position:0% +regressing on an interaction not anymore + + + align:start position:0% +regressing on an interaction not anymore +on a treated dummy but on a number of + + align:start position:0% +on a treated dummy but on a number of + + + align:start position:0% +on a treated dummy but on a number of +school per thousand kids dummy + + align:start position:0% + + + + align:start position:0% + +and that gives me this regression again + + align:start position:0% +and that gives me this regression again + + + align:start position:0% +and that gives me this regression again +that I can do by comparing + + align:start position:0% +that I can do by comparing + + + align:start position:0% +that I can do by comparing +uh just the young to the old + + align:start position:0% +uh just the young to the old + + + align:start position:0% +uh just the young to the old +and so now this is interpret is saying + + align:start position:0% +and so now this is interpret is saying + + + align:start position:0% +and so now this is interpret is saying +that in the places that + + align:start position:0% +that in the places that + + + align:start position:0% +that in the places that +that got one more school for each extra + + align:start position:0% +that got one more school for each extra + + + align:start position:0% +that got one more school for each extra +School per thousand kids + + align:start position:0% +School per thousand kids + + + align:start position:0% +School per thousand kids +the increase in education between The + + align:start position:0% +the increase in education between The + + + align:start position:0% +the increase in education between The +Young and the old court is 0.12 years + + align:start position:0% +Young and the old court is 0.12 years + + + align:start position:0% +Young and the old court is 0.12 years +faster + + align:start position:0% + + + + align:start position:0% + +does that make sense + + align:start position:0% +does that make sense + + + align:start position:0% +does that make sense +so this is how we + + align:start position:0% +so this is how we + + + align:start position:0% +so this is how we +we read that that's the regression + + align:start position:0% +we read that that's the regression + + + align:start position:0% +we read that that's the regression +we you can you could have read data you + + align:start position:0% +we you can you could have read data you + + + align:start position:0% +we you can you could have read data you +could have run that as a regression of + + align:start position:0% +could have run that as a regression of + + + align:start position:0% +could have run that as a regression of +the difference between The Young and the + + align:start position:0% +the difference between The Young and the + + + align:start position:0% +the difference between The Young and the +old on the number of schools per capita + + align:start position:0% +old on the number of schools per capita + + + align:start position:0% +old on the number of schools per capita +that were built in the region of birth + + align:start position:0% +that were built in the region of birth + + + align:start position:0% +that were built in the region of birth +of + + align:start position:0% +of + + + align:start position:0% +of +controlling for any differences between + + align:start position:0% +controlling for any differences between + + + align:start position:0% +controlling for any differences between +the region + + align:start position:0% +the region + + + align:start position:0% +the region +and we can do the same the same + + align:start position:0% +and we can do the same the same + + + align:start position:0% +and we can do the same the same +experiment between the + + align:start position:0% +experiment between the + + + align:start position:0% +experiment between the +between the the the old and super and + + align:start position:0% +between the the the old and super and + + + align:start position:0% +between the the the old and super and +the super old + + align:start position:0% +the super old + + + align:start position:0% +the super old +and + + align:start position:0% +and + + + align:start position:0% +and +um + + align:start position:0% +um + + + align:start position:0% +um +things are now much more precise + + align:start position:0% +things are now much more precise + + + align:start position:0% +things are now much more precise +although they are too precise for + + align:start position:0% +although they are too precise for + + + align:start position:0% +although they are too precise for +residents that in that I will come in a + + align:start position:0% +residents that in that I will come in a + + + align:start position:0% +residents that in that I will come in a +minute uh my standard errors are + + align:start position:0% +minute uh my standard errors are + + + align:start position:0% +minute uh my standard errors are +completely off in that paper + + align:start position:0% +completely off in that paper + + + align:start position:0% +completely off in that paper +um + + align:start position:0% +um + + + align:start position:0% +um +I I didn't know but I didn't know any + + align:start position:0% +I I didn't know but I didn't know any + + + align:start position:0% +I I didn't know but I didn't know any +better but I now do know so I'll do so + + align:start position:0% +better but I now do know so I'll do so + + + align:start position:0% +better but I now do know so I'll do so +this is another half of for reason I'll + + align:start position:0% +this is another half of for reason I'll + + + align:start position:0% +this is another half of for reason I'll +discuss in a bit but at least it seems + + align:start position:0% +discuss in a bit but at least it seems + + + align:start position:0% +discuss in a bit but at least it seems +quite a bit more precise oh a lot more + + align:start position:0% +quite a bit more precise oh a lot more + + + align:start position:0% +quite a bit more precise oh a lot more +questions + + align:start position:0% +questions + + + align:start position:0% +questions +so that's good it looks like every + + align:start position:0% +so that's good it looks like every + + + align:start position:0% +so that's good it looks like every +thousand schools increase the number of + + align:start position:0% +thousand schools increase the number of + + + align:start position:0% +thousand schools increase the number of +year by by around 12 years and now we + + align:start position:0% +year by by around 12 years and now we + + + align:start position:0% +year by by around 12 years and now we +can do + + align:start position:0% +can do + + + align:start position:0% +can do +the we can use the fact that in fact we + + align:start position:0% +the we can use the fact that in fact we + + + align:start position:0% +the we can use the fact that in fact we +have many cohorts and also that perhaps + + align:start position:0% +have many cohorts and also that perhaps + + + align:start position:0% +have many cohorts and also that perhaps +we have a prediction + + align:start position:0% +we have a prediction + + + align:start position:0% +we have a prediction +so instead of controlling first of all + + align:start position:0% +so instead of controlling first of all + + + align:start position:0% +so instead of controlling first of all +instead of controlling for for just the + + align:start position:0% +instead of controlling for for just the + + + align:start position:0% +instead of controlling for for just the +post I could control for + + align:start position:0% +post I could control for + + + align:start position:0% +post I could control for +uh one the meter area that's not going + + align:start position:0% +uh one the meter area that's not going + + + align:start position:0% +uh one the meter area that's not going +to change anything + + align:start position:0% +to change anything + + + align:start position:0% +to change anything +but more interestingly + + align:start position:0% +but more interestingly + + + align:start position:0% +but more interestingly +I could instead of having just an + + align:start position:0% +I could instead of having just an + + + align:start position:0% +I could instead of having just an +interaction for post and and the number + + align:start position:0% +interaction for post and and the number + + + align:start position:0% +interaction for post and and the number +of schools I'm going to now + + align:start position:0% +of schools I'm going to now + + + align:start position:0% +of schools I'm going to now +control I'm going to have an interaction + + align:start position:0% +control I'm going to have an interaction + + + align:start position:0% +control I'm going to have an interaction +for every year dummy + + align:start position:0% +for every year dummy + + + align:start position:0% +for every year dummy +and uh and the number of schools + + align:start position:0% +and uh and the number of schools + + + align:start position:0% +and uh and the number of schools +which you can think to this the way this + + align:start position:0% +which you can think to this the way this + + + align:start position:0% +which you can think to this the way this +is written which starts at from the + + align:start position:0% +is written which starts at from the + + + align:start position:0% +is written which starts at from the +absolutely uh youngest people oldest + + align:start position:0% +absolutely uh youngest people oldest + + + align:start position:0% +absolutely uh youngest people oldest +people until the very end you can think + + align:start position:0% +people until the very end you can think + + + align:start position:0% +people until the very end you can think +of running a series of different diff + + align:start position:0% +of running a series of different diff + + + align:start position:0% +of running a series of different diff +where every time you're comparing other + + align:start position:0% +where every time you're comparing other + + + align:start position:0% +where every time you're comparing other +people born in 19 I think the oldest + + align:start position:0% +people born in 19 I think the oldest + + + align:start position:0% +people born in 19 I think the oldest +people are born + + align:start position:0% +people are born + + + align:start position:0% +people are born +1950 or something + + align:start position:0% +1950 or something + + + align:start position:0% +1950 or something +you compare them to people who are born + + align:start position:0% +you compare them to people who are born + + + align:start position:0% +you compare them to people who are born +you do a different diff between the 51 + + align:start position:0% +you do a different diff between the 51 + + + align:start position:0% +you do a different diff between the 51 +core to 50. the difference between 51 + + align:start position:0% +core to 50. the difference between 51 + + + align:start position:0% +core to 50. the difference between 51 +and 50. + + align:start position:0% +and 50. + + + align:start position:0% +and 50. +I regressed on the number of schools + + align:start position:0% +I regressed on the number of schools + + + align:start position:0% +I regressed on the number of schools +that were built and then the difference + + align:start position:0% +that were built and then the difference + + + align:start position:0% +that were built and then the difference +between 52 and 50 on the number of + + align:start position:0% +between 52 and 50 on the number of + + + align:start position:0% +between 52 and 50 on the number of +schools that were built etc etc + + align:start position:0% +schools that were built etc etc + + + align:start position:0% +schools that were built etc etc +and that builds you your + + align:start position:0% +and that builds you your + + + align:start position:0% +and that builds you your +so this first one is just Twitter and + + align:start position:0% +so this first one is just Twitter and + + + align:start position:0% +so this first one is just Twitter and +the second one is combined with the + + align:start position:0% +the second one is combined with the + + + align:start position:0% +the second one is combined with the +treatment of schools and that gives you + + align:start position:0% +treatment of schools and that gives you + + + align:start position:0% +treatment of schools and that gives you +this typical event study graph + + align:start position:0% +this typical event study graph + + + align:start position:0% +this typical event study graph +uh + + align:start position:0% +uh + + + align:start position:0% +uh +so this is the one for education + + align:start position:0% +so this is the one for education + + + align:start position:0% +so this is the one for education +where you know I started here at zero + + align:start position:0% +where you know I started here at zero + + + align:start position:0% +where you know I started here at zero +for 24 for the oldest for the oldest + + align:start position:0% +for 24 for the oldest for the oldest + + + align:start position:0% +for 24 for the oldest for the oldest +people + + align:start position:0% +people + + + align:start position:0% +people +and so this is a different diff + + align:start position:0% +and so this is a different diff + + + align:start position:0% +and so this is a different diff +um sort of the continuous definitive for + + align:start position:0% +um sort of the continuous definitive for + + + align:start position:0% +um sort of the continuous definitive for +the 23 + + align:start position:0% +the 23 + + + align:start position:0% +the 23 +for the 22 Etc this is one regression + + align:start position:0% +for the 22 Etc this is one regression + + + align:start position:0% +for the 22 Etc this is one regression +but this is each of this dot compares to + + align:start position:0% +but this is each of this dot compares to + + + align:start position:0% +but this is each of this dot compares to +to the oldest people + + align:start position:0% +to the oldest people + + + align:start position:0% +to the oldest people +and I do have a prediction that there + + align:start position:0% +and I do have a prediction that there + + + align:start position:0% +and I do have a prediction that there +was what wasn't any school built that + + align:start position:0% +was what wasn't any school built that + + + align:start position:0% +was what wasn't any school built that +these guys could go to if they are older + + align:start position:0% +these guys could go to if they are older + + + align:start position:0% +these guys could go to if they are older +than 12 in 1974 so I shouldn't see all + + align:start position:0% +than 12 in 1974 so I shouldn't see all + + + align:start position:0% +than 12 in 1974 so I shouldn't see all +of these guys should be zero and then as + + align:start position:0% +of these guys should be zero and then as + + + align:start position:0% +of these guys should be zero and then as +schools more schools get built and + + align:start position:0% +schools more schools get built and + + + align:start position:0% +schools more schools get built and +people are younger so they they get to + + align:start position:0% +people are younger so they they get to + + + align:start position:0% +people are younger so they they get to +enjoy them for a longer period of time + + align:start position:0% +enjoy them for a longer period of time + + + align:start position:0% +enjoy them for a longer period of time +the the prediction is that the treatment + + align:start position:0% +the the prediction is that the treatment + + + align:start position:0% +the the prediction is that the treatment +should + + align:start position:0% +should + + + align:start position:0% +should +the treatment effect should increase + + align:start position:0% +the treatment effect should increase + + + align:start position:0% +the treatment effect should increase +so at that time + + align:start position:0% +so at that time + + + align:start position:0% +so at that time +I think people really like that graph + + align:start position:0% +I think people really like that graph + + + align:start position:0% +I think people really like that graph +since then they have become very very + + align:start position:0% +since then they have become very very + + + align:start position:0% +since then they have become very very +very + + align:start position:0% +very + + + align:start position:0% +very +common and fashionable and important so + + align:start position:0% +common and fashionable and important so + + + align:start position:0% +common and fashionable and important so +I'll uh and so this graph has a lot of + + align:start position:0% +I'll uh and so this graph has a lot of + + + align:start position:0% +I'll uh and so this graph has a lot of +issues it's not funny it's not the way + + align:start position:0% +issues it's not funny it's not the way + + + align:start position:0% +issues it's not funny it's not the way +that one would construct such a graph + + align:start position:0% +that one would construct such a graph + + + align:start position:0% +that one would construct such a graph +today and I'll show you all of the + + align:start position:0% +today and I'll show you all of the + + + align:start position:0% +today and I'll show you all of the +things what need to add + + align:start position:0% +things what need to add + + + align:start position:0% +things what need to add +but at this time I you know I I it was + + align:start position:0% +but at this time I you know I I it was + + + align:start position:0% +but at this time I you know I I it was +kind of pretty satisfying that if you + + align:start position:0% +kind of pretty satisfying that if you + + + align:start position:0% +kind of pretty satisfying that if you +eyeball this looks like a straight line + + align:start position:0% +eyeball this looks like a straight line + + + align:start position:0% +eyeball this looks like a straight line +this looks like an increasing line + + align:start position:0% +this looks like an increasing line + + + align:start position:0% +this looks like an increasing line +and that's what we would expect so + + align:start position:0% +and that's what we would expect so + + + align:start position:0% +and that's what we would expect so +that's on College + + align:start position:0% + + + + align:start position:0% + +once we have uh found this we can say + + align:start position:0% +once we have uh found this we can say + + + align:start position:0% +once we have uh found this we can say +well now that I have convinced myself + + align:start position:0% +well now that I have convinced myself + + + align:start position:0% +well now that I have convinced myself +that this is in fact zero + + align:start position:0% +that this is in fact zero + + + align:start position:0% +that this is in fact zero +I can impose it which gives me a large + + align:start position:0% +I can impose it which gives me a large + + + align:start position:0% +I can impose it which gives me a large +control cohort and now I can construct + + align:start position:0% +control cohort and now I can construct + + + align:start position:0% +control cohort and now I can construct +my defend if all with respect to the + + align:start position:0% +my defend if all with respect to the + + + align:start position:0% +my defend if all with respect to the +control cohort so all of this is going + + align:start position:0% +control cohort so all of this is going + + + align:start position:0% +control cohort so all of this is going +to be normalized + + align:start position:0% +to be normalized + + + align:start position:0% +to be normalized +now my nose is having Zero Effect + + align:start position:0% +now my nose is having Zero Effect + + + align:start position:0% +now my nose is having Zero Effect +compared to uh to them + + align:start position:0% +compared to uh to them + + + align:start position:0% +compared to uh to them +and then this is going to be compared to + + align:start position:0% +and then this is going to be compared to + + + align:start position:0% +and then this is going to be compared to +the entire group so someone asked why + + align:start position:0% +the entire group so someone asked why + + + align:start position:0% +the entire group so someone asked why +would you do that well you you do that + + align:start position:0% +would you do that well you you do that + + + align:start position:0% +would you do that well you you do that +because you get much more precise result + + align:start position:0% +because you get much more precise result + + + align:start position:0% +because you get much more precise result +if you have a control group that's much + + align:start position:0% +if you have a control group that's much + + + align:start position:0% +if you have a control group that's much +fat much larger + + align:start position:0% +fat much larger + + + align:start position:0% +fat much larger +um + + align:start position:0% +um + + + align:start position:0% +um +and oh + + align:start position:0% + + + + align:start position:0% + +so that's what I did in that table uh + + align:start position:0% +so that's what I did in that table uh + + + align:start position:0% +so that's what I did in that table uh +where I still I estimate + + align:start position:0% +where I still I estimate + + + align:start position:0% +where I still I estimate +that's what's done here we are here + + align:start position:0% +that's what's done here we are here + + + align:start position:0% +that's what's done here we are here +running aggression with only a 10 meal + + align:start position:0% +running aggression with only a 10 meal + + + align:start position:0% +running aggression with only a 10 meal +or 11 dummies which are all the people + + align:start position:0% +or 11 dummies which are all the people + + + align:start position:0% +or 11 dummies which are all the people +treated and there are various treatment + + align:start position:0% +treated and there are various treatment + + + align:start position:0% +treated and there are various treatment +effects as they each + + align:start position:0% + + + + align:start position:0% + +uh and then once we've done it for wages + + align:start position:0% +uh and then once we've done it for wages + + + align:start position:0% +uh and then once we've done it for wages +we can also for Education we can also do + + align:start position:0% +we can also for Education we can also do + + + align:start position:0% +we can also for Education we can also do +it for wages which will lead to what + + align:start position:0% +it for wages which will lead to what + + + align:start position:0% +it for wages which will lead to what +we'll discuss next time for the + + align:start position:0% +we'll discuss next time for the + + + align:start position:0% +we'll discuss next time for the +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so that's all nice uh this is a very + + align:start position:0% +so that's all nice uh this is a very + + + align:start position:0% +so that's all nice uh this is a very +typical example of a different div + + align:start position:0% +typical example of a different div + + + align:start position:0% +typical example of a different div +two-way fixed effect that have become + + align:start position:0% +two-way fixed effect that have become + + + align:start position:0% +two-way fixed effect that have become +super popular in applied economics and + + align:start position:0% +super popular in applied economics and + + + align:start position:0% +super popular in applied economics and +you're gonna keep seeing them this one + + align:start position:0% +you're gonna keep seeing them this one + + + align:start position:0% +you're gonna keep seeing them this one +is a simple one because everyone got + + align:start position:0% +is a simple one because everyone got + + + align:start position:0% +is a simple one because everyone got +treated at the same time + + align:start position:0% +treated at the same time + + + align:start position:0% +treated at the same time +the only kind of complication is that + + align:start position:0% +the only kind of complication is that + + + align:start position:0% +the only kind of complication is that +the the effect that the treatment is + + align:start position:0% +the the effect that the treatment is + + + align:start position:0% +the the effect that the treatment is +introduced progressively + + align:start position:0% +introduced progressively + + + align:start position:0% +introduced progressively +so we would not expect + + align:start position:0% +so we would not expect + + + align:start position:0% +so we would not expect +no effect and then a program effect + + align:start position:0% +no effect and then a program effect + + + align:start position:0% +no effect and then a program effect +because we expect the treatment itself + + align:start position:0% +because we expect the treatment itself + + + align:start position:0% +because we expect the treatment itself +the intensity keeps increasing so the + + align:start position:0% +the intensity keeps increasing so the + + + align:start position:0% +the intensity keeps increasing so the +impact should also keep increasing + + align:start position:0% +impact should also keep increasing + + + align:start position:0% +impact should also keep increasing +there are also many cases where states + + align:start position:0% +there are also many cases where states + + + align:start position:0% +there are also many cases where states +are adopting policies in a staggered + + align:start position:0% +are adopting policies in a staggered + + + align:start position:0% +are adopting policies in a staggered +fashion or regions are adopting a policy + + align:start position:0% +fashion or regions are adopting a policy + + + align:start position:0% +fashion or regions are adopting a policy +in a staggered fashion so for example + + align:start position:0% +in a staggered fashion so for example + + + align:start position:0% +in a staggered fashion so for example +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +you could have a a you know changes the + + align:start position:0% +you could have a a you know changes the + + + align:start position:0% +you could have a a you know changes the +minimum minimum wage laws that one State + + align:start position:0% +minimum minimum wage laws that one State + + + align:start position:0% +minimum minimum wage laws that one State +uh a post and then another one and then + + align:start position:0% +uh a post and then another one and then + + + align:start position:0% +uh a post and then another one and then +another one and another one and then you + + align:start position:0% +another one and another one and then you + + + align:start position:0% +another one and another one and then you +have you you can also compare even in + + align:start position:0% +have you you can also compare even in + + + align:start position:0% +have you you can also compare even in +these settings even if everyone + + align:start position:0% +these settings even if everyone + + + align:start position:0% +these settings even if everyone +eventually adopts you can still estimate + + align:start position:0% +eventually adopts you can still estimate + + + align:start position:0% +eventually adopts you can still estimate +the impact of the policy by comparing + + align:start position:0% +the impact of the policy by comparing + + + align:start position:0% +the impact of the policy by comparing +for example people who haven't adopted + + align:start position:0% +for example people who haven't adopted + + + align:start position:0% +for example people who haven't adopted +yet that people to people who + + align:start position:0% +yet that people to people who + + + align:start position:0% +yet that people to people who +to people who have already adopted and + + align:start position:0% +to people who have already adopted and + + + align:start position:0% +to people who have already adopted and +that group keeps changing over time + + align:start position:0% +that group keeps changing over time + + + align:start position:0% +that group keeps changing over time +so in this setting so that's called the + + align:start position:0% +so in this setting so that's called the + + + align:start position:0% +so in this setting so that's called the +staggered the staggered design this is a + + align:start position:0% +staggered the staggered design this is a + + + align:start position:0% +staggered the staggered design this is a +one time one shot the policy starts + + align:start position:0% +one time one shot the policy starts + + + align:start position:0% +one time one shot the policy starts +that's those examples are staggered + + align:start position:0% +that's those examples are staggered + + + align:start position:0% +that's those examples are staggered +design and there is a whole literature + + align:start position:0% +design and there is a whole literature + + + align:start position:0% +design and there is a whole literature +for how to do these things right a first + + align:start position:0% +for how to do these things right a first + + + align:start position:0% +for how to do these things right a first +thing we staggered design is that you + + align:start position:0% +thing we staggered design is that you + + + align:start position:0% +thing we staggered design is that you +you want to to uh um + + align:start position:0% +you want to to uh um + + + align:start position:0% +you want to to uh um +put them in the right place you want to + + align:start position:0% +put them in the right place you want to + + + align:start position:0% +put them in the right place you want to +relabel them such that zero is the + + align:start position:0% +relabel them such that zero is the + + + align:start position:0% +relabel them such that zero is the +beginning of the + + align:start position:0% +beginning of the + + + align:start position:0% +beginning of the +of time is that you know it's a time + + align:start position:0% +of time is that you know it's a time + + + align:start position:0% +of time is that you know it's a time +where a particular State introduces the + + align:start position:0% +where a particular State introduces the + + + align:start position:0% +where a particular State introduces the +the policy and everything is + + align:start position:0% +the policy and everything is + + + align:start position:0% +the policy and everything is +you will draw your event study graph + + align:start position:0% +you will draw your event study graph + + + align:start position:0% +you will draw your event study graph +not in calendar time + + align:start position:0% +not in calendar time + + + align:start position:0% +not in calendar time +but in a + + align:start position:0% +but in a + + + align:start position:0% +but in a +pre and push the event time + + align:start position:0% +pre and push the event time + + + align:start position:0% +pre and push the event time +event being the policies being adopted + + align:start position:0% +event being the policies being adopted + + + align:start position:0% +event being the policies being adopted +in a particular place does that make + + align:start position:0% +in a particular place does that make + + + align:start position:0% +in a particular place does that make +sense + + align:start position:0% +sense + + + align:start position:0% +sense +I mentioned that because I'm going to + + align:start position:0% +I mentioned that because I'm going to + + + align:start position:0% +I mentioned that because I'm going to +show you an event studies graph before + + align:start position:0% +show you an event studies graph before + + + align:start position:0% +show you an event studies graph before +I'm going to understand what it means + + align:start position:0% +I'm going to understand what it means + + + align:start position:0% +I'm going to understand what it means +when the policies are staggered + + align:start position:0% +when the policies are staggered + + + align:start position:0% +when the policies are staggered +so there is an active literature on how + + align:start position:0% +so there is an active literature on how + + + align:start position:0% +so there is an active literature on how +to do it right which means that this + + align:start position:0% +to do it right which means that this + + + align:start position:0% +to do it right which means that this +paper is you know + + align:start position:0% +paper is you know + + + align:start position:0% +paper is you know +not right anymore fortunately it's the + + align:start position:0% +not right anymore fortunately it's the + + + align:start position:0% +not right anymore fortunately it's the +finding you are still mostly right but + + align:start position:0% +finding you are still mostly right but + + + align:start position:0% +finding you are still mostly right but +uh + + align:start position:0% +uh + + + align:start position:0% +uh +there is a lot of things you would do + + align:start position:0% +there is a lot of things you would do + + + align:start position:0% +there is a lot of things you would do +differently first of all is the standard + + align:start position:0% +differently first of all is the standard + + + align:start position:0% +differently first of all is the standard +error + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% +um + + + align:start position:0% +um +so we discussed at some point very + + align:start position:0% +so we discussed at some point very + + + align:start position:0% +so we discussed at some point very +briefly the idea of clustering standard + + align:start position:0% +briefly the idea of clustering standard + + + align:start position:0% +briefly the idea of clustering standard +errors so at the minimum + + align:start position:0% +errors so at the minimum + + + align:start position:0% +errors so at the minimum +how would you cluster the standard there + + align:start position:0% +how would you cluster the standard there + + + align:start position:0% +how would you cluster the standard there +are in a in a different div program like + + align:start position:0% +are in a in a different div program like + + + align:start position:0% +are in a in a different div program like +this one where you have individual + + align:start position:0% +this one where you have individual + + + align:start position:0% +this one where you have individual +detail but the pro the treatment the + + align:start position:0% +detail but the pro the treatment the + + + align:start position:0% +detail but the pro the treatment the +program is allocated at the district + + align:start position:0% +program is allocated at the district + + + align:start position:0% +program is allocated at the district +level + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +at the minimum you want to Cluster the + + align:start position:0% +at the minimum you want to Cluster the + + + align:start position:0% +at the minimum you want to Cluster the +districts of caboopa 10 times here + + align:start position:0% +districts of caboopa 10 times here + + + align:start position:0% +districts of caboopa 10 times here +and that because that's where you know + + align:start position:0% +and that because that's where you know + + + align:start position:0% +and that because that's where you know +everyone + + align:start position:0% +everyone + + + align:start position:0% +everyone +in a particular District in a particular + + align:start position:0% +in a particular District in a particular + + + align:start position:0% +in a particular District in a particular +year is has the same number of schools + + align:start position:0% +year is has the same number of schools + + + align:start position:0% +year is has the same number of schools +so that's one + + align:start position:0% +so that's one + + + align:start position:0% +so that's one +which is not done in that people but + + align:start position:0% +which is not done in that people but + + + align:start position:0% +which is not done in that people but +it's easy to do it doesn't change much + + align:start position:0% +it's easy to do it doesn't change much + + + align:start position:0% +it's easy to do it doesn't change much +but could have you know if the outcomes + + align:start position:0% +but could have you know if the outcomes + + + align:start position:0% +but could have you know if the outcomes +between people in a given District here + + align:start position:0% +between people in a given District here + + + align:start position:0% +between people in a given District here +were called + + align:start position:0% +were called + + + align:start position:0% +were called +then uh you need to then there is one + + align:start position:0% +then uh you need to then there is one + + + align:start position:0% +then uh you need to then there is one +more worry + + align:start position:0% +more worry + + + align:start position:0% +more worry +which is that + + align:start position:0% +which is that + + + align:start position:0% +which is that +suppose that instead of having annual + + align:start position:0% +suppose that instead of having annual + + + align:start position:0% +suppose that instead of having annual +data in fact I I think in that data set + + align:start position:0% +data in fact I I think in that data set + + + align:start position:0% +data in fact I I think in that data set +I have people uh exact uh birth date + + align:start position:0% + + + + align:start position:0% + +so I aggregated it by year of birth + + align:start position:0% +so I aggregated it by year of birth + + + align:start position:0% +so I aggregated it by year of birth +but in truth you know people's months of + + align:start position:0% +but in truth you know people's months of + + + align:start position:0% +but in truth you know people's months of +birth also affected the + + align:start position:0% +birth also affected the + + + align:start position:0% +birth also affected the +so + + align:start position:0% +so + + + align:start position:0% +so +instead of + + align:start position:0% +instead of + + + align:start position:0% +instead of +aggregating instead of having a great + + align:start position:0% +aggregating instead of having a great + + + align:start position:0% +aggregating instead of having a great +aggregating the data running the + + align:start position:0% +aggregating the data running the + + + align:start position:0% +aggregating the data running the +regression at the district time here + + align:start position:0% +regression at the district time here + + + align:start position:0% +regression at the district time here +level I could have said let me run it at + + align:start position:0% +level I could have said let me run it at + + + align:start position:0% +level I could have said let me run it at +the district 10 months + + align:start position:0% +the district 10 months + + + align:start position:0% +the district 10 months +right why not it should be more + + align:start position:0% +right why not it should be more + + + align:start position:0% +right why not it should be more +precisely going to give you more data + + align:start position:0% + + + + align:start position:0% + +um and suppose that I you know very + + align:start position:0% +um and suppose that I you know very + + + align:start position:0% +um and suppose that I you know very +seriously cluster my standard there are + + align:start position:0% +seriously cluster my standard there are + + + align:start position:0% +seriously cluster my standard there are +at the district a month + + align:start position:0% +at the district a month + + + align:start position:0% +at the district a month +suddenly I have many more clusters than + + align:start position:0% +suddenly I have many more clusters than + + + align:start position:0% +suddenly I have many more clusters than +in District time here so I'm going to + + align:start position:0% +in District time here so I'm going to + + + align:start position:0% +in District time here so I'm going to +get results that should be much more + + align:start position:0% +get results that should be much more + + + align:start position:0% +get results that should be much more +precise does that sound right + + align:start position:0% + + + + align:start position:0% + +could move further I could say well I'm + + align:start position:0% +could move further I could say well I'm + + + align:start position:0% +could move further I could say well I'm +going to aggregate at the district time + + align:start position:0% +going to aggregate at the district time + + + align:start position:0% +going to aggregate at the district time +day of birth + + align:start position:0% +day of birth + + + align:start position:0% +day of birth +probably I'm back to you know very small + + align:start position:0% +probably I'm back to you know very small + + + align:start position:0% +probably I'm back to you know very small +clusters now a lot of very small + + align:start position:0% +clusters now a lot of very small + + + align:start position:0% +clusters now a lot of very small +clusters should become very precise + + align:start position:0% +clusters should become very precise + + + align:start position:0% +clusters should become very precise +uh should I want to do that + + align:start position:0% + + + + align:start position:0% + +what sounds + + align:start position:0% +what sounds + + + align:start position:0% +what sounds +but + + align:start position:0% + + + + align:start position:0% + +yes + + align:start position:0% +yes + + + align:start position:0% +yes +um you eventually run out of Freedom + + align:start position:0% +um you eventually run out of Freedom + + + align:start position:0% +um you eventually run out of Freedom +degrees with degrees of freedom I don't + + align:start position:0% +degrees with degrees of freedom I don't + + + align:start position:0% +degrees with degrees of freedom I don't +know because I'm not running I'm still + + align:start position:0% +know because I'm not running I'm still + + + align:start position:0% +know because I'm not running I'm still +running exactly the same regression so + + align:start position:0% +running exactly the same regression so + + + align:start position:0% +running exactly the same regression so +in term of the number of or I'm going to + + align:start position:0% +in term of the number of or I'm going to + + + align:start position:0% +in term of the number of or I'm going to +have more dummies for a day of birth and + + align:start position:0% +have more dummies for a day of birth and + + + align:start position:0% +have more dummies for a day of birth and +but that's not a new problem because I + + align:start position:0% +but that's not a new problem because I + + + align:start position:0% +but that's not a new problem because I +also have a lot of observations not have + + align:start position:0% +also have a lot of observations not have + + + align:start position:0% +also have a lot of observations not have +treated and control people inside the + + align:start position:0% +treated and control people inside the + + + align:start position:0% +treated and control people inside the +same cluster yeah I could have very + + align:start position:0% +same cluster yeah I could have very + + + align:start position:0% +same cluster yeah I could have very +small clusters but that's fine I'm going + + align:start position:0% +small clusters but that's fine I'm going + + + align:start position:0% +small clusters but that's fine I'm going +to have the smaller cluster the better + + align:start position:0% +to have the smaller cluster the better + + + align:start position:0% +to have the smaller cluster the better +per se + + align:start position:0% +per se + + + align:start position:0% +per se +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +exactly it sounds a bit like a + + align:start position:0% +exactly it sounds a bit like a + + + align:start position:0% +exactly it sounds a bit like a +manufacturing data I'm not manufacturing + + align:start position:0% +manufacturing data I'm not manufacturing + + + align:start position:0% +manufacturing data I'm not manufacturing +detail because the number of + + align:start position:0% +detail because the number of + + + align:start position:0% +detail because the number of +observations will be the same but I'm + + align:start position:0% +observations will be the same but I'm + + + align:start position:0% +observations will be the same but I'm +reducing the cluster size we agreed that + + align:start position:0% +reducing the cluster size we agreed that + + + align:start position:0% +reducing the cluster size we agreed that +I needed to Cluster the level of the + + align:start position:0% +I needed to Cluster the level of the + + + align:start position:0% +I needed to Cluster the level of the +unit of the treatment and we said well + + align:start position:0% +unit of the treatment and we said well + + + align:start position:0% +unit of the treatment and we said well +that's about that year time district and + + align:start position:0% +that's about that year time district and + + + align:start position:0% +that's about that year time district and +then now I'm making it well year times + + align:start position:0% +then now I'm making it well year times + + + align:start position:0% +then now I'm making it well year times +months time this trick so I have more + + align:start position:0% +months time this trick so I have more + + + align:start position:0% +months time this trick so I have more +cluster basically more effective + + align:start position:0% +cluster basically more effective + + + align:start position:0% +cluster basically more effective +observation + + align:start position:0% +observation + + + align:start position:0% +observation +sounds like a + + align:start position:0% +sounds like a + + + align:start position:0% +sounds like a +I'm creating precision + + align:start position:0% +I'm creating precision + + + align:start position:0% +I'm creating precision +that seems too good to be true and the + + align:start position:0% +that seems too good to be true and the + + + align:start position:0% +that seems too good to be true and the +issue is that + + align:start position:0% +issue is that + + + align:start position:0% +issue is that +the treatment is very correlated by your + + align:start position:0% +the treatment is very correlated by your + + + align:start position:0% +the treatment is very correlated by your +year of birth + + align:start position:0% +year of birth + + + align:start position:0% +year of birth +in particular someone born in February + + align:start position:0% +in particular someone born in February + + + align:start position:0% +in particular someone born in February +or March is treated almost the same + + align:start position:0% +or March is treated almost the same + + + align:start position:0% +or March is treated almost the same +right their level of treatment is almost + + align:start position:0% +right their level of treatment is almost + + + align:start position:0% +right their level of treatment is almost +the same + + align:start position:0% +the same + + + align:start position:0% +the same +so + + align:start position:0% + + + + align:start position:0% + +that would in and of itself be fine + + align:start position:0% +that would in and of itself be fine + + + align:start position:0% +that would in and of itself be fine +except that their outcomes might also be + + align:start position:0% +except that their outcomes might also be + + + align:start position:0% +except that their outcomes might also be +correlated because they are in the state + + align:start position:0% +correlated because they are in the state + + + align:start position:0% +correlated because they are in the state +you know they are in a labor market + + align:start position:0% +you know they are in a labor market + + + align:start position:0% +you know they are in a labor market +roughly at the same time Etc so yeah + + align:start position:0% +roughly at the same time Etc so yeah + + + align:start position:0% +roughly at the same time Etc so yeah +what if it's I guess it's a similar + + align:start position:0% +what if it's I guess it's a similar + + + align:start position:0% +what if it's I guess it's a similar +scenario what if we observe multiple + + align:start position:0% +scenario what if we observe multiple + + + align:start position:0% +scenario what if we observe multiple +observations of the same person yeah + + align:start position:0% +observations of the same person yeah + + + align:start position:0% +observations of the same person yeah +likewise if we observe multiple + + align:start position:0% +likewise if we observe multiple + + + align:start position:0% +likewise if we observe multiple +observation of the same person we + + align:start position:0% +observation of the same person we + + + align:start position:0% +observation of the same person we +wouldn't want to treat them as + + align:start position:0% +wouldn't want to treat them as + + + align:start position:0% +wouldn't want to treat them as +individual observations + + align:start position:0% +individual observations + + + align:start position:0% +individual observations +exactly so the question in that case we + + align:start position:0% +exactly so the question in that case we + + + align:start position:0% +exactly so the question in that case we +would cluster by individual we would say + + align:start position:0% +would cluster by individual we would say + + + align:start position:0% +would cluster by individual we would say +you know they all come from the same + + align:start position:0% +you know they all come from the same + + + align:start position:0% +you know they all come from the same +person we would either make an + + align:start position:0% +person we would either make an + + + align:start position:0% +person we would either make an +assumption about how what the time + + align:start position:0% +assumption about how what the time + + + align:start position:0% +assumption about how what the time +series of this error is + + align:start position:0% +series of this error is + + + align:start position:0% +series of this error is +or we would just cluster by individuals + + align:start position:0% +or we would just cluster by individuals + + + align:start position:0% +or we would just cluster by individuals +saying I'm acknowledging that a rule + + align:start position:0% +saying I'm acknowledging that a rule + + + align:start position:0% +saying I'm acknowledging that a rule +coming from the same individually are + + align:start position:0% +coming from the same individually are + + + align:start position:0% +coming from the same individually are +not independent observation therefore I + + align:start position:0% +not independent observation therefore I + + + align:start position:0% +not independent observation therefore I +need to take that into account in my + + align:start position:0% +need to take that into account in my + + + align:start position:0% +need to take that into account in my +standard level similarly for people who + + align:start position:0% +standard level similarly for people who + + + align:start position:0% +standard level similarly for people who +live in the same district here we say + + align:start position:0% +live in the same district here we say + + + align:start position:0% +live in the same district here we say +well I live together they do a lot of + + align:start position:0% +well I live together they do a lot of + + + align:start position:0% +well I live together they do a lot of +thing in common + + align:start position:0% +thing in common + + + align:start position:0% +thing in common +we need to Cluster at that level because + + align:start position:0% +we need to Cluster at that level because + + + align:start position:0% +we need to Cluster at that level because +the treatment is also clustered at that + + align:start position:0% +the treatment is also clustered at that + + + align:start position:0% +the treatment is also clustered at that +level + + align:start position:0% +level + + + align:start position:0% +level +and then similarly as you both are + + align:start position:0% +and then similarly as you both are + + + align:start position:0% +and then similarly as you both are +getting to + + align:start position:0% +getting to + + + align:start position:0% +getting to +um people who are + + align:start position:0% + + + + align:start position:0% + +living in in who are from the same year + + align:start position:0% +living in in who are from the same year + + + align:start position:0% +living in in who are from the same year +of birth or similar years of very + + align:start position:0% +of birth or similar years of very + + + align:start position:0% +of birth or similar years of very +similar months of birth I've experienced + + align:start position:0% +similar months of birth I've experienced + + + align:start position:0% +similar months of birth I've experienced +similar education condition labor market + + align:start position:0% +similar education condition labor market + + + align:start position:0% +similar education condition labor market +condition the outcomes likely to be + + align:start position:0% +condition the outcomes likely to be + + + align:start position:0% +condition the outcomes likely to be +correlated and their treatment is very + + align:start position:0% +correlated and their treatment is very + + + align:start position:0% +correlated and their treatment is very +polluted in fact with defend if it's + + align:start position:0% +polluted in fact with defend if it's + + + align:start position:0% +polluted in fact with defend if it's +really extreme because once someone is + + align:start position:0% +really extreme because once someone is + + + align:start position:0% +really extreme because once someone is +treated they're still treated forever + + align:start position:0% +treated they're still treated forever + + + align:start position:0% +treated they're still treated forever +and therefore there is a mechanical very + + align:start position:0% +and therefore there is a mechanical very + + + align:start position:0% +and therefore there is a mechanical very +strong correlation between treatment + + align:start position:0% +strong correlation between treatment + + + align:start position:0% +strong correlation between treatment +status of people who are who are born in + + align:start position:0% +status of people who are who are born in + + + align:start position:0% +status of people who are who are born in +in related years + + align:start position:0% +in related years + + + align:start position:0% +in related years +because it's not it doesn't go off on + + align:start position:0% +because it's not it doesn't go off on + + + align:start position:0% +because it's not it doesn't go off on +and off therefore we need to take that + + align:start position:0% +and off therefore we need to take that + + + align:start position:0% +and off therefore we need to take that +serial correlation over time into + + align:start position:0% +serial correlation over time into + + + align:start position:0% +serial correlation over time into +account the simplest way is to do + + align:start position:0% +account the simplest way is to do + + + align:start position:0% +account the simplest way is to do +exactly what you're saying which is + + align:start position:0% +exactly what you're saying which is + + + align:start position:0% +exactly what you're saying which is +instead of clustering at the district + + align:start position:0% +instead of clustering at the district + + + align:start position:0% +instead of clustering at the district +times here level we are going to + + align:start position:0% +times here level we are going to + + + align:start position:0% +times here level we are going to +District we're going to Cluster at the + + align:start position:0% +District we're going to Cluster at the + + + align:start position:0% +District we're going to Cluster at the +district level + + align:start position:0% +district level + + + align:start position:0% +district level +to take into account the Coalition in + + align:start position:0% +to take into account the Coalition in + + + align:start position:0% +to take into account the Coalition in +the outcomes of people who live in the + + align:start position:0% +the outcomes of people who live in the + + + align:start position:0% +the outcomes of people who live in the +same district in abundant different here + + align:start position:0% +same district in abundant different here + + + align:start position:0% +same district in abundant different here +the clustering so the condition is not + + align:start position:0% +the clustering so the condition is not + + + align:start position:0% +the clustering so the condition is not +one and but the clustering let you know + + align:start position:0% +one and but the clustering let you know + + + align:start position:0% +one and but the clustering let you know +we let the data figure out roughly what + + align:start position:0% +we let the data figure out roughly what + + + align:start position:0% +we let the data figure out roughly what +it is unless we have very few clusters + + align:start position:0% +it is unless we have very few clusters + + + align:start position:0% +it is unless we have very few clusters +in which case you start you need to do + + align:start position:0% +in which case you start you need to do + + + align:start position:0% +in which case you start you need to do +other things yeah and if you have data + + align:start position:0% +other things yeah and if you have data + + + align:start position:0% +other things yeah and if you have data +like monthly data of the construction of + + align:start position:0% +like monthly data of the construction of + + + align:start position:0% +like monthly data of the construction of +schools would it make sense to have + + align:start position:0% +schools would it make sense to have + + + align:start position:0% +schools would it make sense to have +clusters that depend on the time as well + + align:start position:0% +clusters that depend on the time as well + + + align:start position:0% +clusters that depend on the time as well +yes you could you could do that you + + align:start position:0% +yes you could you could do that you + + + align:start position:0% +yes you could you could do that you +could say if you had monthly data on + + align:start position:0% +could say if you had monthly data on + + + align:start position:0% +could say if you had monthly data on +school construction you would have your + + align:start position:0% +school construction you would have your + + + align:start position:0% +school construction you would have your +treatment defined and a month time place + + align:start position:0% +treatment defined and a month time place + + + align:start position:0% +treatment defined and a month time place +but then you would also want to Cluster + + align:start position:0% +but then you would also want to Cluster + + + align:start position:0% +but then you would also want to Cluster +the place level because for sure there + + align:start position:0% +the place level because for sure there + + + align:start position:0% +the place level because for sure there +is a lot of photo correlation in the + + align:start position:0% +is a lot of photo correlation in the + + + align:start position:0% +is a lot of photo correlation in the +number of schools constructed because it + + align:start position:0% +number of schools constructed because it + + + align:start position:0% +number of schools constructed because it +keeps going up it doesn't go down and + + align:start position:0% +keeps going up it doesn't go down and + + + align:start position:0% +keeps going up it doesn't go down and +the outcomes might also be correlated + + align:start position:0% +the outcomes might also be correlated + + + align:start position:0% +the outcomes might also be correlated +for people in similar times + + align:start position:0% +for people in similar times + + + align:start position:0% +for people in similar times +so that's the first thing we have to do + + align:start position:0% +so that's the first thing we have to do + + + align:start position:0% +so that's the first thing we have to do +that is we've known yeah put it also I + + align:start position:0% +that is we've known yeah put it also I + + + align:start position:0% +that is we've known yeah put it also I +mean this would still be I think you + + align:start position:0% +mean this would still be I think you + + + align:start position:0% +mean this would still be I think you +would still have our approach that you + + align:start position:0% +would still have our approach that you + + + align:start position:0% +would still have our approach that you +can handle once you considering the + + align:start position:0% +can handle once you considering the + + + align:start position:0% +can handle once you considering the +district level but would it be like + + align:start position:0% +district level but would it be like + + + align:start position:0% +district level but would it be like +slightly more promoting calendar year to + + align:start position:0% +slightly more promoting calendar year to + + + align:start position:0% +slightly more promoting calendar year to +use like uh school year so you're + + align:start position:0% +use like uh school year so you're + + + align:start position:0% +use like uh school year so you're +getting much closer Born Into the same + + align:start position:0% +getting much closer Born Into the same + + + align:start position:0% +getting much closer Born Into the same +uh school year yeah you could have a bit + + align:start position:0% +uh school year yeah you could have a bit + + + align:start position:0% +uh school year yeah you could have a bit +more Precision that maybe if you and you + + align:start position:0% +more Precision that maybe if you and you + + + align:start position:0% +more Precision that maybe if you and you +you could you could try playing with + + align:start position:0% +you could you could try playing with + + + align:start position:0% +you could you could try playing with +that I do think the + + align:start position:0% +that I do think the + + + align:start position:0% +that I do think the +calendar + + align:start position:0% + + + + align:start position:0% + +in this particular instance but I'm not + + align:start position:0% +in this particular instance but I'm not + + + align:start position:0% +in this particular instance but I'm not +positive yes but that so that doesn't + + align:start position:0% +positive yes but that so that doesn't + + + align:start position:0% +positive yes but that so that doesn't +that's not about it's not just another + + align:start position:0% +that's not about it's not just another + + + align:start position:0% +that's not about it's not just another +problem it's uh Define your treatment in + + align:start position:0% +problem it's uh Define your treatment in + + + align:start position:0% +problem it's uh Define your treatment in +a more precise way so you're going + + align:start position:0% +a more precise way so you're going + + + align:start position:0% +a more precise way so you're going +that's going to give you more precision + + align:start position:0% +that's going to give you more precision + + + align:start position:0% +that's going to give you more precision +uh that is going to be reflected in your + + align:start position:0% +uh that is going to be reflected in your + + + align:start position:0% +uh that is going to be reflected in your +scenario + + align:start position:0% +scenario + + + align:start position:0% +scenario +so first thing + + align:start position:0% +so first thing + + + align:start position:0% +so first thing +that I didn't do that I now know you + + align:start position:0% +that I didn't do that I now know you + + + align:start position:0% +that I didn't do that I now know you +have to Cluster at the at the district + + align:start position:0% +have to Cluster at the at the district + + + align:start position:0% +have to Cluster at the at the district +level and when you do that actually the + + align:start position:0% +level and when you do that actually the + + + align:start position:0% +level and when you do that actually the +the estimates are less because you still + + align:start position:0% +the estimates are less because you still + + + align:start position:0% +the estimates are less because you still +have a significant impact on education + + align:start position:0% +have a significant impact on education + + + align:start position:0% +have a significant impact on education +but the the impact on wages are a bit uh + + align:start position:0% +but the the impact on wages are a bit uh + + + align:start position:0% +but the the impact on wages are a bit uh +I'll be dicey + + align:start position:0% + + + + align:start position:0% + +then you have this uh a series of series + + align:start position:0% +then you have this uh a series of series + + + align:start position:0% +then you have this uh a series of series +of people that are much more recent that + + align:start position:0% +of people that are much more recent that + + + align:start position:0% +of people that are much more recent that +you're going to see in the you're going + + align:start position:0% +you're going to see in the you're going + + + align:start position:0% +you're going to see in the you're going +to see more investigation and in the in + + align:start position:0% +to see more investigation and in the in + + + align:start position:0% +to see more investigation and in the in +the Forum set but I'm going to make the + + align:start position:0% +the Forum set but I'm going to make the + + + align:start position:0% +the Forum set but I'm going to make the +list for you these are my understanding + + align:start position:0% +list for you these are my understanding + + + align:start position:0% +list for you these are my understanding +of the people that needs to be read now + + align:start position:0% +of the people that needs to be read now + + + align:start position:0% +of the people that needs to be read now +if you're interested in doing ever doing + + align:start position:0% +if you're interested in doing ever doing + + + align:start position:0% +if you're interested in doing ever doing +an event study or difference in + + align:start position:0% +an event study or difference in + + + align:start position:0% +an event study or difference in +difference in your life + + align:start position:0% +difference in your life + + + align:start position:0% +difference in your life +one is the good vacant point which makes + + align:start position:0% +one is the good vacant point which makes + + + align:start position:0% +one is the good vacant point which makes +this point of uh stacking the data + + align:start position:0% +this point of uh stacking the data + + + align:start position:0% +this point of uh stacking the data +appropriately if the event is staggered + + align:start position:0% +appropriately if the event is staggered + + + align:start position:0% +appropriately if the event is staggered +uh one is so this idea that it's a bit + + align:start position:0% +uh one is so this idea that it's a bit + + + align:start position:0% +uh one is so this idea that it's a bit +loose that oh there is there a pre-trend + + align:start position:0% +loose that oh there is there a pre-trend + + + align:start position:0% +loose that oh there is there a pre-trend +that everybody is testing + + align:start position:0% +that everybody is testing + + + align:start position:0% +that everybody is testing +uh that takes this paper uh takes that + + align:start position:0% +uh that takes this paper uh takes that + + + align:start position:0% +uh that takes this paper uh takes that +idea more seriously in saying first of + + align:start position:0% +idea more seriously in saying first of + + + align:start position:0% +idea more seriously in saying first of +all how would I test for Patron second + + align:start position:0% +all how would I test for Patron second + + + align:start position:0% +all how would I test for Patron second +of all + + align:start position:0% +of all + + + align:start position:0% +of all +you could not reject the patron but they + + align:start position:0% +you could not reject the patron but they + + + align:start position:0% +you could not reject the patron but they +are there anywhere so we we should + + align:start position:0% +are there anywhere so we we should + + + align:start position:0% +are there anywhere so we we should +control for them anyways so it gives you + + align:start position:0% +control for them anyways so it gives you + + + align:start position:0% +control for them anyways so it gives you +some tips for controlling for any + + align:start position:0% +some tips for controlling for any + + + align:start position:0% +some tips for controlling for any +pre-trends + + align:start position:0% +pre-trends + + + align:start position:0% +pre-trends +um + + align:start position:0% +um + + + align:start position:0% +um +this paper is great I'm gonna show you + + align:start position:0% +this paper is great I'm gonna show you + + + align:start position:0% +this paper is great I'm gonna show you +two graph from this paper but it's + + align:start position:0% +two graph from this paper but it's + + + align:start position:0% +two graph from this paper but it's +fantastic that's in your I think + + align:start position:0% +fantastic that's in your I think + + + align:start position:0% +fantastic that's in your I think +eventually probably every everything you + + align:start position:0% +eventually probably every everything you + + + align:start position:0% +eventually probably every everything you +need to know in is in here I'm willing + + align:start position:0% +need to know in is in here I'm willing + + + align:start position:0% +need to know in is in here I'm willing +to bet that that becomes the standard + + align:start position:0% +to bet that that becomes the standard + + + align:start position:0% +to bet that that becomes the standard +and everybody else is forgotten it's a + + align:start position:0% +and everybody else is forgotten it's a + + + align:start position:0% +and everybody else is forgotten it's a +review paper on how to do an event study + + align:start position:0% +review paper on how to do an event study + + + align:start position:0% +review paper on how to do an event study +graph as well as how to control for her + + align:start position:0% +graph as well as how to control for her + + + align:start position:0% +graph as well as how to control for her +for the pre-trend uh and I'll show you + + align:start position:0% +for the pre-trend uh and I'll show you + + + align:start position:0% +for the pre-trend uh and I'll show you +their event study graph we can compare + + align:start position:0% +their event study graph we can compare + + + align:start position:0% +their event study graph we can compare +it to mine + + align:start position:0% +it to mine + + + align:start position:0% +it to mine +but it's a review + + align:start position:0% +but it's a review + + + align:start position:0% +but it's a review +for the annual review or something like + + align:start position:0% +for the annual review or something like + + + align:start position:0% +for the annual review or something like +that so it's very pedagric here it's + + align:start position:0% +that so it's very pedagric here it's + + + align:start position:0% +that so it's very pedagric here it's +well done and there are stata codes to + + align:start position:0% +well done and there are stata codes to + + + align:start position:0% +well done and there are stata codes to +it so my sense is it's your One-Stop + + align:start position:0% +it so my sense is it's your One-Stop + + + align:start position:0% +it so my sense is it's your One-Stop +shop I just found out about it recently + + align:start position:0% +shop I just found out about it recently + + + align:start position:0% +shop I just found out about it recently +otherwise it would be in the in the + + align:start position:0% +otherwise it would be in the in the + + + align:start position:0% +otherwise it would be in the in the +syllabus with three stars + + align:start position:0% +syllabus with three stars + + + align:start position:0% +syllabus with three stars +uh then another issue you might get into + + align:start position:0% +uh then another issue you might get into + + + align:start position:0% +uh then another issue you might get into +is when if the treatment effect are + + align:start position:0% +is when if the treatment effect are + + + align:start position:0% +is when if the treatment effect are +heterogeneous + + align:start position:0% +heterogeneous + + + align:start position:0% +heterogeneous +um + + align:start position:0% +um + + + align:start position:0% +um +then uh what you get from just a simple + + align:start position:0% +then uh what you get from just a simple + + + align:start position:0% +then uh what you get from just a simple +difference in difference in the stack + + align:start position:0% +difference in difference in the stack + + + align:start position:0% +difference in difference in the stack +design is the weighted effect of all the + + align:start position:0% +design is the weighted effect of all the + + + align:start position:0% +design is the weighted effect of all the +treatment effects + + align:start position:0% +treatment effects + + + align:start position:0% +treatment effects +and usually that's fine but if you're + + align:start position:0% +and usually that's fine but if you're + + + align:start position:0% +and usually that's fine but if you're +unlucky some weights could be negative + + align:start position:0% +unlucky some weights could be negative + + + align:start position:0% +unlucky some weights could be negative +in which case you're a bit screwed so + + align:start position:0% +in which case you're a bit screwed so + + + align:start position:0% +in which case you're a bit screwed so +there is some work uh to correct for + + align:start position:0% +there is some work uh to correct for + + + align:start position:0% +there is some work uh to correct for +that construct the right standard there + + align:start position:0% +that construct the right standard there + + + align:start position:0% +that construct the right standard there +are + + align:start position:0% +are + + + align:start position:0% +are +um it's an issue uh probably to check I + + align:start position:0% +um it's an issue uh probably to check I + + + align:start position:0% +um it's an issue uh probably to check I +would in my sense probably less of a + + align:start position:0% +would in my sense probably less of a + + + align:start position:0% +would in my sense probably less of a +central issue than than doing that + + align:start position:0% +central issue than than doing that + + + align:start position:0% +central issue than than doing that +properly so here is their sort of + + align:start position:0% +properly so here is their sort of + + + align:start position:0% +properly so here is their sort of +after all of the suggestions have been + + align:start position:0% +after all of the suggestions have been + + + align:start position:0% +after all of the suggestions have been +implemented + + align:start position:0% +implemented + + + align:start position:0% +implemented +um so maybe you don't even need to read + + align:start position:0% +um so maybe you don't even need to read + + + align:start position:0% +um so maybe you don't even need to read +the paper you can refer to this very + + align:start position:0% +the paper you can refer to this very + + + align:start position:0% +the paper you can refer to this very +year + + align:start position:0% +year + + + align:start position:0% +year +neat summary of it I do think you should + + align:start position:0% +neat summary of it I do think you should + + + align:start position:0% +neat summary of it I do think you should +read the paper but what do we need to do + + align:start position:0% +read the paper but what do we need to do + + + align:start position:0% +read the paper but what do we need to do +well this is our Advanced study so it's + + align:start position:0% +well this is our Advanced study so it's + + + align:start position:0% +well this is our Advanced study so it's +zero is the point in our case in my my + + align:start position:0% +zero is the point in our case in my my + + + align:start position:0% +zero is the point in our case in my my +case it would be uh 12 in 1974 would be + + align:start position:0% +case it would be uh 12 in 1974 would be + + + align:start position:0% +case it would be uh 12 in 1974 would be +my zero + + align:start position:0% +my zero + + + align:start position:0% +my zero +so what did I do wrong so first of all + + align:start position:0% +so what did I do wrong so first of all + + + align:start position:0% +so what did I do wrong so first of all +let's suggests that it is better to + + align:start position:0% +let's suggests that it is better to + + + align:start position:0% +let's suggests that it is better to +normalize the year before I normalized + + align:start position:0% +normalize the year before I normalized + + + align:start position:0% +normalize the year before I normalized +here at the beginning of my period but + + align:start position:0% +here at the beginning of my period but + + + align:start position:0% +here at the beginning of my period but +of course that doesn't make much sense + + align:start position:0% +of course that doesn't make much sense + + + align:start position:0% +of course that doesn't make much sense +you would want to normalize the year + + align:start position:0% +you would want to normalize the year + + + align:start position:0% +you would want to normalize the year +before the study so I should have used + + align:start position:0% +before the study so I should have used + + + align:start position:0% +before the study so I should have used +as my omitted category people who were + + align:start position:0% +as my omitted category people who were + + + align:start position:0% +as my omitted category people who were +11 in 1972 so you normalize at at -1 + + align:start position:0% +11 in 1972 so you normalize at at -1 + + + align:start position:0% +11 in 1972 so you normalize at at -1 +then I have no confidence interval in + + align:start position:0% +then I have no confidence interval in + + + align:start position:0% +then I have no confidence interval in +any of my graphs actually some of them + + align:start position:0% +any of my graphs actually some of them + + + align:start position:0% +any of my graphs actually some of them +have but not too much so you should have + + align:start position:0% +have but not too much so you should have + + + align:start position:0% +have but not too much so you should have +the confidence interval that everybody + + align:start position:0% +the confidence interval that everybody + + + align:start position:0% +the confidence interval that everybody +is now doing what they suggest adding as + + align:start position:0% +is now doing what they suggest adding as + + + align:start position:0% +is now doing what they suggest adding as +well are these longer this longer + + align:start position:0% +well are these longer this longer + + + align:start position:0% +well are these longer this longer +confidence interval which is a uniform + + align:start position:0% +confidence interval which is a uniform + + + align:start position:0% +confidence interval which is a uniform +confidence band so it takes into account + + align:start position:0% +confidence band so it takes into account + + + align:start position:0% +confidence band so it takes into account +the fact that you are not just testing + + align:start position:0% +the fact that you are not just testing + + + align:start position:0% +the fact that you are not just testing +one by one by one but you are testing + + align:start position:0% +one by one by one but you are testing + + + align:start position:0% +one by one by one but you are testing +all of them + + align:start position:0% +all of them + + + align:start position:0% +all of them +so the standard they are a bit wider + + align:start position:0% +so the standard they are a bit wider + + + align:start position:0% +so the standard they are a bit wider +then here they put the average of all + + align:start position:0% +then here they put the average of all + + + align:start position:0% +then here they put the average of all +these points so it's basically the + + align:start position:0% +these points so it's basically the + + + align:start position:0% +these points so it's basically the +average of your outcome in the it's + + align:start position:0% +average of your outcome in the it's + + + align:start position:0% +average of your outcome in the it's +normalized as zero in the regression but + + align:start position:0% +normalized as zero in the regression but + + + align:start position:0% +normalized as zero in the regression but +it it's not zero of course there is so + + align:start position:0% +it it's not zero of course there is so + + + align:start position:0% +it it's not zero of course there is so +it's an average of your outcome in the + + align:start position:0% +it's an average of your outcome in the + + + align:start position:0% +it's an average of your outcome in the +pre-period so it gives you a sense of + + align:start position:0% +pre-period so it gives you a sense of + + + align:start position:0% +pre-period so it gives you a sense of +magnitude and how the how the magnitude + + align:start position:0% +magnitude and how the how the magnitude + + + align:start position:0% +magnitude and how the how the magnitude +of the point estimated compare + + align:start position:0% +of the point estimated compare + + + align:start position:0% +of the point estimated compare +um + + align:start position:0% +um + + + align:start position:0% +um +what else do they propose they propose + + align:start position:0% +what else do they propose they propose + + + align:start position:0% +what else do they propose they propose +also to uh to plot what you think is the + + align:start position:0% +also to uh to plot what you think is the + + + align:start position:0% +also to uh to plot what you think is the +more restricted model so in this case + + align:start position:0% +more restricted model so in this case + + + align:start position:0% +more restricted model so in this case +the Assumption was that there is an + + align:start position:0% +the Assumption was that there is an + + + align:start position:0% +the Assumption was that there is an +effect there you know there is a + + align:start position:0% +effect there you know there is a + + + align:start position:0% +effect there you know there is a +prepared and then there is + + align:start position:0% +prepared and then there is + + + align:start position:0% +prepared and then there is +an impact so that's the restricted model + + align:start position:0% +an impact so that's the restricted model + + + align:start position:0% +an impact so that's the restricted model +so you can see you know the extent to + + align:start position:0% +so you can see you know the extent to + + + align:start position:0% +so you can see you know the extent to +which there is deviation from that + + align:start position:0% +which there is deviation from that + + + align:start position:0% +which there is deviation from that +restricted model in my case I would have + + align:start position:0% +restricted model in my case I would have + + + align:start position:0% +restricted model in my case I would have +built I would have drawn this + + align:start position:0% +built I would have drawn this + + + align:start position:0% +built I would have drawn this +or in fact I could have drawn something + + align:start position:0% +or in fact I could have drawn something + + + align:start position:0% +or in fact I could have drawn something +somewhere at some point in the paper I + + align:start position:0% +somewhere at some point in the paper I + + + align:start position:0% +somewhere at some point in the paper I +had drawn the number of school built + + align:start position:0% +had drawn the number of school built + + + align:start position:0% +had drawn the number of school built +so you could build you could construct + + align:start position:0% +so you could build you could construct + + + align:start position:0% +so you could build you could construct +for every child how many years of + + align:start position:0% +for every child how many years of + + + align:start position:0% +for every child how many years of +effective school they would enjoy + + align:start position:0% +effective school they would enjoy + + + align:start position:0% +effective school they would enjoy +and that would be your restricted + + align:start position:0% +and that would be your restricted + + + align:start position:0% +and that would be your restricted +effectively effective were only + + align:start position:0% +effectively effective were only + + + align:start position:0% +effectively effective were only +proportional to the number of school + + align:start position:0% +proportional to the number of school + + + align:start position:0% +proportional to the number of school +multiplied by the number of years you + + align:start position:0% +multiplied by the number of years you + + + align:start position:0% +multiplied by the number of years you +have to enjoy so you could compare it to + + align:start position:0% +have to enjoy so you could compare it to + + + align:start position:0% +have to enjoy so you could compare it to +the the shape of the coefficient that + + align:start position:0% +the the shape of the coefficient that + + + align:start position:0% +the the shape of the coefficient that +makes it easier for the reader to do + + align:start position:0% +makes it easier for the reader to do + + + align:start position:0% +makes it easier for the reader to do +that + + align:start position:0% +that + + + align:start position:0% +that +finally you could introduce you could + + align:start position:0% +finally you could introduce you could + + + align:start position:0% +finally you could introduce you could +put in the legend of the graph + + align:start position:0% +put in the legend of the graph + + + align:start position:0% +put in the legend of the graph +so here the the what they suggesting the + + align:start position:0% +so here the the what they suggesting the + + + align:start position:0% +so here the the what they suggesting the +people but for some reason it's not here + + align:start position:0% +people but for some reason it's not here + + + align:start position:0% +people but for some reason it's not here +it's a p-value of all these guys being + + align:start position:0% +it's a p-value of all these guys being + + + align:start position:0% +it's a p-value of all these guys being +negative + + align:start position:0% +negative + + + align:start position:0% +negative +so here you would not be able to reject + + align:start position:0% +so here you would not be able to reject + + + align:start position:0% +so here you would not be able to reject +I think they are nice and negative so a + + align:start position:0% +I think they are nice and negative so a + + + align:start position:0% +I think they are nice and negative so a +value test of all these things being + + align:start position:0% +value test of all these things being + + + align:start position:0% +value test of all these things being +negative so that's the test a formal + + align:start position:0% +negative so that's the test a formal + + + align:start position:0% +negative so that's the test a formal +test of so it being zero formal test of + + align:start position:0% +test of so it being zero formal test of + + + align:start position:0% +test of so it being zero formal test of +of uh zero quick hand + + align:start position:0% +of uh zero quick hand + + + align:start position:0% +of uh zero quick hand +and then a formal test of the + + align:start position:0% +and then a formal test of the + + + align:start position:0% +and then a formal test of the +restricting model in this case the + + align:start position:0% +restricting model in this case the + + + align:start position:0% +restricting model in this case the +restricted model is that the treatment + + align:start position:0% +restricted model is that the treatment + + + align:start position:0% +restricted model is that the treatment +effect is constant once it starts and + + align:start position:0% +effect is constant once it starts and + + + align:start position:0% +effect is constant once it starts and +here you can see that it looks like it's + + align:start position:0% +here you can see that it looks like it's + + + align:start position:0% +here you can see that it looks like it's +not and in fact they introduce here the + + align:start position:0% +not and in fact they introduce here the + + + align:start position:0% +not and in fact they introduce here the +test for a constant effect post and are + + align:start position:0% +test for a constant effect post and are + + + align:start position:0% +test for a constant effect post and are +rejected so that's in the + + align:start position:0% +rejected so that's in the + + + align:start position:0% +rejected so that's in the +that you can put that in the + + align:start position:0% +that you can put that in the + + + align:start position:0% +that you can put that in the +in The Legend So I put both the + + align:start position:0% +in The Legend So I put both the + + + align:start position:0% +in The Legend So I put both the +pre-trend and the constant treatment + + align:start position:0% +pre-trend and the constant treatment + + + align:start position:0% +pre-trend and the constant treatment +effect + + align:start position:0% +effect + + + align:start position:0% +effect +but for some reason on this graph they + + align:start position:0% +but for some reason on this graph they + + + align:start position:0% +but for some reason on this graph they +only have them + + align:start position:0% +only have them + + + align:start position:0% +only have them +so that's your state-of-the-art event + + align:start position:0% +so that's your state-of-the-art event + + + align:start position:0% +so that's your state-of-the-art event +study graph + + align:start position:0% +study graph + + + align:start position:0% +study graph +if you're a second year students you're + + align:start position:0% +if you're a second year students you're + + + align:start position:0% +if you're a second year students you're +fighting your heart + + align:start position:0% +fighting your heart + + + align:start position:0% +fighting your heart +Johan check on your paper you want + + align:start position:0% +Johan check on your paper you want + + + align:start position:0% +Johan check on your paper you want +and you have to you are planning on an + + align:start position:0% +and you have to you are planning on an + + + align:start position:0% +and you have to you are planning on an +event study graph it needs to looks like + + align:start position:0% +event study graph it needs to looks like + + + align:start position:0% +event study graph it needs to looks like +that + + align:start position:0% +that + + + align:start position:0% +that +and that's another suggestion they have + + align:start position:0% +and that's another suggestion they have + + + align:start position:0% +and that's another suggestion they have +is to uh to plot kind of the the the + + align:start position:0% +is to uh to plot kind of the the the + + + align:start position:0% +is to uh to plot kind of the the the +least Wiggly + + align:start position:0% +least Wiggly + + + align:start position:0% +least Wiggly +line + + align:start position:0% +line + + + align:start position:0% +line +uh that that fits all the points in the + + align:start position:0% +uh that that fits all the points in the + + + align:start position:0% +uh that that fits all the points in the +graph + + align:start position:0% +graph + + + align:start position:0% +graph +so here are the least wiggly line that + + align:start position:0% +so here are the least wiggly line that + + + align:start position:0% +so here are the least wiggly line that +fits all the point in the graph is a + + align:start position:0% +fits all the point in the graph is a + + + align:start position:0% +fits all the point in the graph is a +straight line + + align:start position:0% +straight line + + + align:start position:0% +straight line +so that basically is a way to tell you + + align:start position:0% +so that basically is a way to tell you + + + align:start position:0% +so that basically is a way to tell you +it doesn't fit it doesn't it does it + + align:start position:0% +it doesn't fit it doesn't it does it + + + align:start position:0% +it doesn't fit it doesn't it does it +looks like this is all pre-tran + + align:start position:0% +looks like this is all pre-tran + + + align:start position:0% +looks like this is all pre-tran +uh and here this one the least weekly + + align:start position:0% +uh and here this one the least weekly + + + align:start position:0% +uh and here this one the least weekly +line possible it's quite wiggly so seems + + align:start position:0% +line possible it's quite wiggly so seems + + + align:start position:0% +line possible it's quite wiggly so seems +very unlikely that this is + + align:start position:0% +very unlikely that this is + + + align:start position:0% +very unlikely that this is +due to + + align:start position:0% +due to + + + align:start position:0% +due to +some other thing that is moving in this + + align:start position:0% +some other thing that is moving in this + + + align:start position:0% +some other thing that is moving in this +funny way so in our case in the case of + + align:start position:0% +funny way so in our case in the case of + + + align:start position:0% +funny way so in our case in the case of +the impress program the least weekly + + align:start position:0% +the impress program the least weekly + + + align:start position:0% +the impress program the least weekly +line that fits all the point would + + align:start position:0% +line that fits all the point would + + + align:start position:0% +line that fits all the point would +probably be have been nice and like that + + align:start position:0% +probably be have been nice and like that + + + align:start position:0% +probably be have been nice and like that +and therefore quite unlikely to be + + align:start position:0% +and therefore quite unlikely to be + + + align:start position:0% +and therefore quite unlikely to be +explainable by something else but it's a + + align:start position:0% +explainable by something else but it's a + + + align:start position:0% +explainable by something else but it's a +way of making these argument in uh Less + + align:start position:0% +way of making these argument in uh Less + + + align:start position:0% +way of making these argument in uh Less +in impressionistic way + + align:start position:0% + + + + align:start position:0% + +so that's the kind of state of the art + + align:start position:0% +so that's the kind of state of the art + + + align:start position:0% +so that's the kind of state of the art +of difference in difference + + align:start position:0% +of difference in difference + + + align:start position:0% +of difference in difference +any question on that + + align:start position:0% + + + + align:start position:0% + +I thought it would be a good good + + align:start position:0% +I thought it would be a good good + + + align:start position:0% +I thought it would be a good good +occasion to put all of this on slides + + align:start position:0% +occasion to put all of this on slides + + + align:start position:0% +occasion to put all of this on slides +and you'll have a convenient way to + + align:start position:0% +and you'll have a convenient way to + + + align:start position:0% +and you'll have a convenient way to +refer to them later + + align:start position:0% +refer to them later + + + align:start position:0% +refer to them later +um + + align:start position:0% + + + + align:start position:0% + +so that's also what you know what I have + + align:start position:0% +so that's also what you know what I have + + + align:start position:0% +so that's also what you know what I have +to say also on substance in terms of + + align:start position:0% +to say also on substance in terms of + + + align:start position:0% +to say also on substance in terms of +what concerns the people's reaction to + + align:start position:0% +what concerns the people's reaction to + + + align:start position:0% +what concerns the people's reaction to +the cost of Education I will go back to + + align:start position:0% +the cost of Education I will go back to + + + align:start position:0% +the cost of Education I will go back to +this paper so many people have asked + + align:start position:0% +this paper so many people have asked + + + align:start position:0% +this paper so many people have asked +about General equilibrium effect and + + align:start position:0% +about General equilibrium effect and + + + align:start position:0% +about General equilibrium effect and +I'll get back to uh + + align:start position:0% +I'll get back to uh + + + align:start position:0% +I'll get back to uh +I get back to to that when we this last + + align:start position:0% +I get back to to that when we this last + + + align:start position:0% +I get back to to that when we this last +time next time actually did write a + + align:start position:0% +time next time actually did write a + + + align:start position:0% +time next time actually did write a +paper about it so I have a paper that + + align:start position:0% +paper about it so I have a paper that + + + align:start position:0% +paper about it so I have a paper that +looks at uh + + align:start position:0% +looks at uh + + + align:start position:0% +looks at uh +the the impact of the school + + align:start position:0% +the the impact of the school + + + align:start position:0% +the the impact of the school +construction on people who were not + + align:start position:0% +construction on people who were not + + + align:start position:0% +construction on people who were not +affected by the school construction to + + align:start position:0% +affected by the school construction to + + + align:start position:0% +affected by the school construction to +get at the to get the equilibrium effect + + align:start position:0% +get at the to get the equilibrium effect + + + align:start position:0% +get at the to get the equilibrium effect +uh let me spend the last uh 10 minutes + + align:start position:0% +uh let me spend the last uh 10 minutes + + + align:start position:0% +uh let me spend the last uh 10 minutes +we have 10 15 minutes we have thinking + + align:start position:0% +we have 10 15 minutes we have thinking + + + align:start position:0% +we have 10 15 minutes we have thinking +about the other aspects of what what + + align:start position:0% +about the other aspects of what what + + + align:start position:0% +about the other aspects of what what +else enters in the in in the education + + align:start position:0% +else enters in the in in the education + + + align:start position:0% +else enters in the in in the education +production function what people seem to + + align:start position:0% +production function what people seem to + + + align:start position:0% +production function what people seem to +be responding to + + align:start position:0% +be responding to + + + align:start position:0% +be responding to +so one very nice feature of a very kind + + align:start position:0% +so one very nice feature of a very kind + + + align:start position:0% +so one very nice feature of a very kind +of specific feature of this model is + + align:start position:0% +of specific feature of this model is + + + align:start position:0% +of specific feature of this model is +people should respond to the perceived + + align:start position:0% +people should respond to the perceived + + + align:start position:0% +people should respond to the perceived +return to education + + align:start position:0% +return to education + + + align:start position:0% +return to education +so how how one would go about testing + + align:start position:0% +so how how one would go about testing + + + align:start position:0% +so how how one would go about testing +that + + align:start position:0% +that + + + align:start position:0% +that +so Rob Jensen first exploited the fact + + align:start position:0% +so Rob Jensen first exploited the fact + + + align:start position:0% +so Rob Jensen first exploited the fact +that people make mistakes on what they + + align:start position:0% +that people make mistakes on what they + + + align:start position:0% +that people make mistakes on what they +think they return to educational and + + align:start position:0% +think they return to educational and + + + align:start position:0% +think they return to educational and +therefore you can just tell them the + + align:start position:0% +therefore you can just tell them the + + + align:start position:0% +therefore you can just tell them the +truth and by telling them the truths you + + align:start position:0% +truth and by telling them the truths you + + + align:start position:0% +truth and by telling them the truths you +are affecting their uh their perceived + + align:start position:0% +are affecting their uh their perceived + + + align:start position:0% +are affecting their uh their perceived +return and you you could see whether + + align:start position:0% +return and you you could see whether + + + align:start position:0% +return and you you could see whether +therefore they react by by + + align:start position:0% +therefore they react by by + + + align:start position:0% +therefore they react by by +going to school more + + align:start position:0% +going to school more + + + align:start position:0% +going to school more +uh so he did this project in the + + align:start position:0% +uh so he did this project in the + + + align:start position:0% +uh so he did this project in the +Dominican Republic + + align:start position:0% +Dominican Republic + + + align:start position:0% +Dominican Republic +where the completion rate for high + + align:start position:0% +where the completion rate for high + + + align:start position:0% +where the completion rate for high +school is low + + align:start position:0% +school is low + + + align:start position:0% +school is low +and his first went to the students and + + align:start position:0% +and his first went to the students and + + + align:start position:0% +and his first went to the students and +asked them + + align:start position:0% +asked them + + + align:start position:0% +asked them +um their view of returning to education + + align:start position:0% +um their view of returning to education + + + align:start position:0% +um their view of returning to education +by + + align:start position:0% +by + + + align:start position:0% +by +comparing by asking them to say how much + + align:start position:0% +comparing by asking them to say how much + + + align:start position:0% +comparing by asking them to say how much +someone is + + align:start position:0% +someone is + + + align:start position:0% +someone is +for those who have complete Primary + + align:start position:0% +for those who have complete Primary + + + align:start position:0% +for those who have complete Primary +School versus those who have completed + + align:start position:0% +School versus those who have completed + + + align:start position:0% +School versus those who have completed +High School what's the difference + + align:start position:0% +High School what's the difference + + + align:start position:0% +High School what's the difference +uh by the way where what's the + + align:start position:0% +uh by the way where what's the + + + align:start position:0% +uh by the way where what's the +so + + align:start position:0% +so + + + align:start position:0% +so +let me finish that and then I'll ask you + + align:start position:0% +let me finish that and then I'll ask you + + + align:start position:0% +let me finish that and then I'll ask you +at Baseline the people seem to be people + + align:start position:0% +at Baseline the people seem to be people + + + align:start position:0% +at Baseline the people seem to be people +here seem to be underestimating the + + align:start position:0% +here seem to be underestimating the + + + align:start position:0% +here seem to be underestimating the +return to education + + align:start position:0% +return to education + + + align:start position:0% +return to education +which by the way is really not a + + align:start position:0% +which by the way is really not a + + + align:start position:0% +which by the way is really not a +generalized finding in my experience + + align:start position:0% +generalized finding in my experience + + + align:start position:0% +generalized finding in my experience +people widely overestimate the returns + + align:start position:0% +people widely overestimate the returns + + + align:start position:0% +people widely overestimate the returns +to education but it's two secondary + + align:start position:0% +to education but it's two secondary + + + align:start position:0% +to education but it's two secondary +education but in this instance they were + + align:start position:0% +education but in this instance they were + + + align:start position:0% +education but in this instance they were +underestimating them + + align:start position:0% +underestimating them + + + align:start position:0% +underestimating them +um + + align:start position:0% +um + + + align:start position:0% +um +that's what that you would get on your + + align:start position:0% +that's what that you would get on your + + + align:start position:0% +that's what that you would get on your +10 increase from uh moving from the 8th + + align:start position:0% +10 increase from uh moving from the 8th + + + align:start position:0% +10 increase from uh moving from the 8th +to the 12th when when in fact it's much + + align:start position:0% +to the 12th when when in fact it's much + + + align:start position:0% +to the 12th when when in fact it's much +bigger than that but then what they did + + align:start position:0% +bigger than that but then what they did + + + align:start position:0% +bigger than that but then what they did +is that they told them the truth + + align:start position:0% +is that they told them the truth + + + align:start position:0% +is that they told them the truth +in some schools + + align:start position:0% +in some schools + + + align:start position:0% +in some schools +so the mean Syrian return are more like + + align:start position:0% +so the mean Syrian return are more like + + + align:start position:0% +so the mean Syrian return are more like +10 percent per year so 40 for going from + + align:start position:0% +10 percent per year so 40 for going from + + + align:start position:0% +10 percent per year so 40 for going from +eighth grade to high school + + align:start position:0% +eighth grade to high school + + + align:start position:0% +eighth grade to high school +and then after some time they compared + + align:start position:0% +and then after some time they compared + + + align:start position:0% +and then after some time they compared +who stays in school but possible they + + align:start position:0% +who stays in school but possible they + + + align:start position:0% +who stays in school but possible they +show that they update their beliefs and + + align:start position:0% +show that they update their beliefs and + + + align:start position:0% +show that they update their beliefs and +I'll show you that in a minute and then + + align:start position:0% +I'll show you that in a minute and then + + + align:start position:0% +I'll show you that in a minute and then +they investigate the impact on education + + align:start position:0% +they investigate the impact on education + + + align:start position:0% +they investigate the impact on education +so before I go further what's the issue + + align:start position:0% +so before I go further what's the issue + + + align:start position:0% +so before I go further what's the issue +is doing that + + align:start position:0% + + + + align:start position:0% + +are in fact even with asking them in + + align:start position:0% +are in fact even with asking them in + + + align:start position:0% +are in fact even with asking them in +this way the difference they thought + + align:start position:0% +this way the difference they thought + + + align:start position:0% +this way the difference they thought +between in the income of someone who has + + align:start position:0% +between in the income of someone who has + + + align:start position:0% +between in the income of someone who has +completed versus not completed + + align:start position:0% + + + + align:start position:0% + +what is potential concern in doing this + + align:start position:0% +what is potential concern in doing this + + + align:start position:0% +what is potential concern in doing this +exercise yeah + + align:start position:0% +exercise yeah + + + align:start position:0% +exercise yeah +[Music] + + align:start position:0% + + + + align:start position:0% + +yeah they might not understand what that + + align:start position:0% +yeah they might not understand what that + + + align:start position:0% +yeah they might not understand what that +means and in some sense + + align:start position:0% + + + + align:start position:0% + +depending on how the question was asked + + align:start position:0% +depending on how the question was asked + + + align:start position:0% +depending on how the question was asked +it's kind of clear if it's like the + + align:start position:0% +it's kind of clear if it's like the + + + align:start position:0% +it's kind of clear if it's like the +return for like an individual who + + align:start position:0% +return for like an individual who + + + align:start position:0% +return for like an individual who +chooses to to build 13 Congress holders + + align:start position:0% +chooses to to build 13 Congress holders + + + align:start position:0% +chooses to to build 13 Congress holders +meeting her a bit like also getting into + + align:start position:0% +meeting her a bit like also getting into + + + align:start position:0% +meeting her a bit like also getting into +accountability + + align:start position:0% +accountability + + + align:start position:0% +accountability +yes exactly exactly and in what is given + + align:start position:0% +yes exactly exactly and in what is given + + + align:start position:0% +yes exactly exactly and in what is given +to them is is full of the ability by us + + align:start position:0% +to them is is full of the ability by us + + + align:start position:0% +to them is is full of the ability by us +potentially or the selection by for many + + align:start position:0% +potentially or the selection by for many + + + align:start position:0% +potentially or the selection by for many +kind + + align:start position:0% +kind + + + align:start position:0% +kind +uh you're telling them the difference + + align:start position:0% +uh you're telling them the difference + + + align:start position:0% +uh you're telling them the difference +between learning of someone who has + + align:start position:0% +between learning of someone who has + + + align:start position:0% +between learning of someone who has +completed and not completed education + + align:start position:0% +completed and not completed education + + + align:start position:0% +completed and not completed education +that's not the returns to education + + align:start position:0% +that's not the returns to education + + + align:start position:0% +that's not the returns to education +that's not the causal effect of + + align:start position:0% +that's not the causal effect of + + + align:start position:0% +that's not the causal effect of +Education + + align:start position:0% +Education + + + align:start position:0% +Education +so potentially I'm lying to people which + + align:start position:0% +so potentially I'm lying to people which + + + align:start position:0% +so potentially I'm lying to people which +is a bit problematic + + align:start position:0% +is a bit problematic + + + align:start position:0% +is a bit problematic +or not lying but giving them an + + align:start position:0% +or not lying but giving them an + + + align:start position:0% +or not lying but giving them an +information that's not + + align:start position:0% +information that's not + + + align:start position:0% +information that's not +accurate it's not accurate for the + + align:start position:0% +accurate it's not accurate for the + + + align:start position:0% +accurate it's not accurate for the +average it might and then the other kind + + align:start position:0% +average it might and then the other kind + + + align:start position:0% +average it might and then the other kind +of part of your answer is that it's not + + align:start position:0% +of part of your answer is that it's not + + + align:start position:0% +of part of your answer is that it's not +even the you know it's about an + + align:start position:0% +even the you know it's about an + + + align:start position:0% +even the you know it's about an +individual it's not necessarily the + + align:start position:0% +individual it's not necessarily the + + + align:start position:0% +individual it's not necessarily the +relevant information for any particular + + align:start position:0% +relevant information for any particular + + + align:start position:0% +relevant information for any particular +individual which of course you don't + + align:start position:0% +individual which of course you don't + + + align:start position:0% +individual which of course you don't +know + + align:start position:0% +know + + + align:start position:0% +know +so that's a little bit of a dicey + + align:start position:0% +so that's a little bit of a dicey + + + align:start position:0% +so that's a little bit of a dicey +project but again maybe you didn't know + + align:start position:0% +project but again maybe you didn't know + + + align:start position:0% +project but again maybe you didn't know +until you know this is this might be + + align:start position:0% +until you know this is this might be + + + align:start position:0% +until you know this is this might be +2020 hindsight + + align:start position:0% +2020 hindsight + + + align:start position:0% +2020 hindsight +but uh that's certainly something that + + align:start position:0% +but uh that's certainly something that + + + align:start position:0% +but uh that's certainly something that +people uh criticized they do find an + + align:start position:0% +people uh criticized they do find an + + + align:start position:0% +people uh criticized they do find an +impact uh on education they find that + + align:start position:0% +impact uh on education they find that + + + align:start position:0% +impact uh on education they find that +people generally update their belief uh + + align:start position:0% +people generally update their belief uh + + + align:start position:0% +people generally update their belief uh +positively and they find an average + + align:start position:0% +positively and they find an average + + + align:start position:0% +positively and they find an average +impact on educational let me show you + + align:start position:0% +impact on educational let me show you + + + align:start position:0% +impact on educational let me show you +the table + + align:start position:0% + + + + align:start position:0% + +have increased on average these + + align:start position:0% +have increased on average these + + + align:start position:0% +have increased on average these +treatments regress foreign + + align:start position:0% + + + + align:start position:0% + +and then uh so this is the average + + align:start position:0% +and then uh so this is the average + + + align:start position:0% +and then uh so this is the average +effect on perceived return and then the + + align:start position:0% +effect on perceived return and then the + + + align:start position:0% +effect on perceived return and then the +average effect on various things without + + align:start position:0% +average effect on various things without + + + align:start position:0% +average effect on various things without +a return whether the uh they finished + + align:start position:0% +a return whether the uh they finished + + + align:start position:0% +a return whether the uh they finished +the years of schooling and then they + + align:start position:0% +the years of schooling and then they + + + align:start position:0% +the years of schooling and then they +actually find larger effect for the for + + align:start position:0% +actually find larger effect for the for + + + align:start position:0% +actually find larger effect for the for +for the rich household and the poor + + align:start position:0% +for the rich household and the poor + + + align:start position:0% +for the rich household and the poor +household possibly because in addition + + align:start position:0% +household possibly because in addition + + + align:start position:0% +household possibly because in addition +people you know there are also maybe + + align:start position:0% +people you know there are also maybe + + + align:start position:0% +people you know there are also maybe +constrained people can't do it + + align:start position:0% +constrained people can't do it + + + align:start position:0% +constrained people can't do it +immediately so return is not the only + + align:start position:0% +immediately so return is not the only + + + align:start position:0% +immediately so return is not the only +thing that entered the decision + + align:start position:0% +thing that entered the decision + + + align:start position:0% +thing that entered the decision +so um + + align:start position:0% +so um + + + align:start position:0% +so um +if you had to run this regression having + + align:start position:0% +if you had to run this regression having + + + align:start position:0% +if you had to run this regression having +done this experiment if you had to run + + align:start position:0% +done this experiment if you had to run + + + align:start position:0% +done this experiment if you had to run +this regression would you run it this + + align:start position:0% +this regression would you run it this + + + align:start position:0% +this regression would you run it this +way or would there be another way to run + + align:start position:0% +way or would there be another way to run + + + align:start position:0% +way or would there be another way to run +it that would make more sense + + align:start position:0% + + + + align:start position:0% + +exactly so at the minimum you should + + align:start position:0% +exactly so at the minimum you should + + + align:start position:0% +exactly so at the minimum you should +think that the treatment + + align:start position:0% +think that the treatment + + + align:start position:0% +think that the treatment +treatment doesn't have a monotonous + + align:start position:0% +treatment doesn't have a monotonous + + + align:start position:0% +treatment doesn't have a monotonous +effect on these other things because + + align:start position:0% +effect on these other things because + + + align:start position:0% +effect on these other things because +some people + + align:start position:0% +some people + + + align:start position:0% +some people +even though on average people were + + align:start position:0% +even though on average people were + + + align:start position:0% +even though on average people were +underestimating it is likely that some + + align:start position:0% +underestimating it is likely that some + + + align:start position:0% +underestimating it is likely that some +people were overestimating and some + + align:start position:0% +people were overestimating and some + + + align:start position:0% +people were overestimating and some +people were underestimating + + align:start position:0% +people were underestimating + + + align:start position:0% +people were underestimating +so at the minimum when you are doing + + align:start position:0% +so at the minimum when you are doing + + + align:start position:0% +so at the minimum when you are doing +this kind of device in treatment and you + + align:start position:0% +this kind of device in treatment and you + + + align:start position:0% +this kind of device in treatment and you +know they have become popular we are + + align:start position:0% +know they have become popular we are + + + align:start position:0% +know they have become popular we are +going to see other examples of that you + + align:start position:0% +going to see other examples of that you + + + align:start position:0% +going to see other examples of that you +should + + align:start position:0% +should + + + align:start position:0% +should +look at you should separate the sample + + align:start position:0% +look at you should separate the sample + + + align:start position:0% +look at you should separate the sample +by the people whose prior you're moving + + align:start position:0% +by the people whose prior you're moving + + + align:start position:0% +by the people whose prior you're moving +up to the people who hire you moving + + align:start position:0% +up to the people who hire you moving + + + align:start position:0% +up to the people who hire you moving +down because you would expect the effect + + align:start position:0% +down because you would expect the effect + + + align:start position:0% +down because you would expect the effect +to go in opposite direction + + align:start position:0% +to go in opposite direction + + + align:start position:0% +to go in opposite direction +well that's just a note of + + align:start position:0% +well that's just a note of + + + align:start position:0% +well that's just a note of +how one could have done that + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +uh given so this paper was criticized + + align:start position:0% +uh given so this paper was criticized + + + align:start position:0% +uh given so this paper was criticized +for what I'm telling you which is that + + align:start position:0% +for what I'm telling you which is that + + + align:start position:0% +for what I'm telling you which is that +basically you're telling people some + + align:start position:0% +basically you're telling people some + + + align:start position:0% +basically you're telling people some +junk that's a little bit uh troubling + + align:start position:0% +junk that's a little bit uh troubling + + + align:start position:0% +junk that's a little bit uh troubling +maybe we shouldn't do that + + align:start position:0% +maybe we shouldn't do that + + + align:start position:0% +maybe we shouldn't do that +um and then there are other people that + + align:start position:0% +um and then there are other people that + + + align:start position:0% +um and then there are other people that +are trying to use people that are trying + + align:start position:0% +are trying to use people that are trying + + + align:start position:0% +are trying to use people that are trying +to use the the real data data from The + + align:start position:0% +to use the the real data data from The + + + align:start position:0% +to use the the real data data from The +Real World to look at the the how people + + align:start position:0% +Real World to look at the the how people + + + align:start position:0% +Real World to look at the the how people +respond to the return to education + + align:start position:0% +respond to the return to education + + + align:start position:0% +respond to the return to education +and older people uh by Foster and + + align:start position:0% +and older people uh by Foster and + + + align:start position:0% +and older people uh by Foster and +rodents flag uh in the ER quite nice + + align:start position:0% +rodents flag uh in the ER quite nice + + + align:start position:0% +rodents flag uh in the ER quite nice +looks at the impact of high yielding + + align:start position:0% +looks at the impact of high yielding + + + align:start position:0% +looks at the impact of high yielding +variety + + align:start position:0% +variety + + + align:start position:0% +variety +and argue that high yielding variety + + align:start position:0% +and argue that high yielding variety + + + align:start position:0% +and argue that high yielding variety +grain has a large impact on returns to + + align:start position:0% +grain has a large impact on returns to + + + align:start position:0% +grain has a large impact on returns to +education because basically you need to + + align:start position:0% +education because basically you need to + + + align:start position:0% +education because basically you need to +be able to read the package and + + align:start position:0% +be able to read the package and + + + align:start position:0% +be able to read the package and +understand what it is and then have some + + align:start position:0% +understand what it is and then have some + + + align:start position:0% +understand what it is and then have some +suggesting evidence that the return to + + align:start position:0% +suggesting evidence that the return to + + + align:start position:0% +suggesting evidence that the return to +high yielding variety is very low for + + align:start position:0% +high yielding variety is very low for + + + align:start position:0% +high yielding variety is very low for +people who are not educated and very + + align:start position:0% +people who are not educated and very + + + align:start position:0% +people who are not educated and very +high for people who are educated so the + + align:start position:0% +high for people who are educated so the + + + align:start position:0% +high for people who are educated so the +introduction + + align:start position:0% +introduction + + + align:start position:0% +introduction +which is a bit sequential as well of + + align:start position:0% +which is a bit sequential as well of + + + align:start position:0% +which is a bit sequential as well of +high yielding variety across Villages + + align:start position:0% +high yielding variety across Villages + + + align:start position:0% +high yielding variety across Villages +has different impact as increases the + + align:start position:0% +has different impact as increases the + + + align:start position:0% +has different impact as increases the +return to education + + align:start position:0% +return to education + + + align:start position:0% +return to education +so that's the first thing that they say + + align:start position:0% +so that's the first thing that they say + + + align:start position:0% +so that's the first thing that they say +and then as a result when you see high + + align:start position:0% +and then as a result when you see high + + + align:start position:0% +and then as a result when you see high +yielding variety + + align:start position:0% +yielding variety + + + align:start position:0% +yielding variety +being introduced that should increase + + align:start position:0% +being introduced that should increase + + + align:start position:0% +being introduced that should increase +people uh educating their kids + + align:start position:0% +people uh educating their kids + + + align:start position:0% +people uh educating their kids +because the return to education have now + + align:start position:0% +because the return to education have now + + + align:start position:0% +because the return to education have now +gone up + + align:start position:0% +gone up + + + align:start position:0% +gone up +and they find that now one issue with + + align:start position:0% +and they find that now one issue with + + + align:start position:0% +and they find that now one issue with +that exercise is that at the same time + + align:start position:0% +that exercise is that at the same time + + + align:start position:0% +that exercise is that at the same time +that it increased the return to + + align:start position:0% +that it increased the return to + + + align:start position:0% +that it increased the return to +education and it should increase + + align:start position:0% +education and it should increase + + + align:start position:0% +education and it should increase +people's income + + align:start position:0% +people's income + + + align:start position:0% +people's income +and we've seen that in you know a richer + + align:start position:0% +and we've seen that in you know a richer + + + align:start position:0% +and we've seen that in you know a richer +model of the world income effect would + + align:start position:0% +model of the world income effect would + + + align:start position:0% +model of the world income effect would +also increase + + align:start position:0% +also increase + + + align:start position:0% +also increase +education in and of itself that's not an + + align:start position:0% +education in and of itself that's not an + + + align:start position:0% +education in and of itself that's not an +issue for them because they don't + + align:start position:0% +issue for them because they don't + + + align:start position:0% +issue for them because they don't +believe in income effect so you know the + + align:start position:0% +believe in income effect so you know the + + + align:start position:0% +believe in income effect so you know the +only thing that could possibly have + + align:start position:0% +only thing that could possibly have + + + align:start position:0% +only thing that could possibly have +happened is um is um is the response to + + align:start position:0% +happened is um is um is the response to + + + align:start position:0% +happened is um is um is the response to +return to education but one could be + + align:start position:0% +return to education but one could be + + + align:start position:0% +return to education but one could be +worried about that + + align:start position:0% +worried about that + + + align:start position:0% +worried about that +two more recent people that have which + + align:start position:0% +two more recent people that have which + + + align:start position:0% +two more recent people that have which +are on the same uh which have the same + + align:start position:0% +are on the same uh which have the same + + + align:start position:0% +are on the same uh which have the same +those two papers have a little bit the + + align:start position:0% +those two papers have a little bit the + + + align:start position:0% +those two papers have a little bit the +same mechanism at hand is a David Atkin + + align:start position:0% +same mechanism at hand is a David Atkin + + + align:start position:0% +same mechanism at hand is a David Atkin +paper and a Sarah Hernandez I was a + + align:start position:0% +paper and a Sarah Hernandez I was a + + + align:start position:0% +paper and a Sarah Hernandez I was a +graduate student Here and Now teaches at + + align:start position:0% +graduate student Here and Now teaches at + + + align:start position:0% +graduate student Here and Now teaches at +Northwestern + + align:start position:0% +Northwestern + + + align:start position:0% +Northwestern +uh they look at export jobs and Export + + align:start position:0% +uh they look at export jobs and Export + + + align:start position:0% +uh they look at export jobs and Export +jobs coming from the government sector + + align:start position:0% +jobs coming from the government sector + + + align:start position:0% +jobs coming from the government sector +mostly in Mexico and the flower sector + + align:start position:0% +mostly in Mexico and the flower sector + + + align:start position:0% +mostly in Mexico and the flower sector +in Colombia + + align:start position:0% +in Colombia + + + align:start position:0% +in Colombia +and they show that when these jobs are + + align:start position:0% +and they show that when these jobs are + + + align:start position:0% +and they show that when these jobs are +introduced it leads to dropouts of girls + + align:start position:0% +introduced it leads to dropouts of girls + + + align:start position:0% +introduced it leads to dropouts of girls +despite the fact that people are richer + + align:start position:0% +despite the fact that people are richer + + + align:start position:0% +despite the fact that people are richer +which they explained by by the fact that + + align:start position:0% +which they explained by by the fact that + + + align:start position:0% +which they explained by by the fact that +the return to education are now lower + + align:start position:0% +the return to education are now lower + + + align:start position:0% +the return to education are now lower +because you don't need to be educated to + + align:start position:0% +because you don't need to be educated to + + + align:start position:0% +because you don't need to be educated to +get any of these jobs so you can get a + + align:start position:0% +get any of these jobs so you can get a + + + align:start position:0% +get any of these jobs so you can get a +good job working in a garment Factory or + + align:start position:0% +good job working in a garment Factory or + + + align:start position:0% +good job working in a garment Factory or +you can get a good job working in a + + align:start position:0% +you can get a good job working in a + + + align:start position:0% +you can get a good job working in a +flower sector without education so + + align:start position:0% +flower sector without education so + + + align:start position:0% +flower sector without education so +people dropped out + + align:start position:0% +people dropped out + + + align:start position:0% +people dropped out +in the example of David they got + + align:start position:0% +in the example of David they got + + + align:start position:0% +in the example of David they got +schooled for it because then the sector + + align:start position:0% +schooled for it because then the sector + + + align:start position:0% +schooled for it because then the sector +disappeared and they found themselves + + align:start position:0% +disappeared and they found themselves + + + align:start position:0% +disappeared and they found themselves +without jobs and without an education + + align:start position:0% +without jobs and without an education + + + align:start position:0% +without jobs and without an education +uh that the full story of that paper but + + align:start position:0% +uh that the full story of that paper but + + + align:start position:0% +uh that the full story of that paper but +so the advantage Advantage the the + + align:start position:0% +so the advantage Advantage the the + + + align:start position:0% +so the advantage Advantage the the +advantage of that example is that the + + align:start position:0% +advantage of that example is that the + + + align:start position:0% +advantage of that example is that the +return to rejection go down at the same + + align:start position:0% +return to rejection go down at the same + + + align:start position:0% +return to rejection go down at the same +time as the income go up so we don't + + align:start position:0% +time as the income go up so we don't + + + align:start position:0% +time as the income go up so we don't +have the the income effect and the + + align:start position:0% +have the the income effect and the + + + align:start position:0% +have the the income effect and the +substitution effect going in in the same + + align:start position:0% +substitution effect going in in the same + + + align:start position:0% +substitution effect going in in the same +direction so if we find education + + align:start position:0% +direction so if we find education + + + align:start position:0% +direction so if we find education +dropping it's + + align:start position:0% +dropping it's + + + align:start position:0% +dropping it's +you know it seems likely that it's + + align:start position:0% +you know it seems likely that it's + + + align:start position:0% +you know it seems likely that it's +because of that + + align:start position:0% +because of that + + + align:start position:0% +because of that +but then Jensen went back like one step + + align:start position:0% +but then Jensen went back like one step + + + align:start position:0% +but then Jensen went back like one step +further and said well you know you + + align:start position:0% +further and said well you know you + + + align:start position:0% +further and said well you know you +didn't like my uh changing the belief so + + align:start position:0% +didn't like my uh changing the belief so + + + align:start position:0% +didn't like my uh changing the belief so +I'm gonna change the return + + align:start position:0% + + + + align:start position:0% + +um that seems like ambitious to say are + + align:start position:0% +um that seems like ambitious to say are + + + align:start position:0% +um that seems like ambitious to say are +you able to change the return to + + align:start position:0% +you able to change the return to + + + align:start position:0% +you able to change the return to +education and he had a great great idea + + align:start position:0% +education and he had a great great idea + + + align:start position:0% +education and he had a great great idea +uh which is to participate in a + + align:start position:0% +uh which is to participate in a + + + align:start position:0% +uh which is to participate in a +recruiting campaign for call centers uh + + align:start position:0% +recruiting campaign for call centers uh + + + align:start position:0% +recruiting campaign for call centers uh +you know these type of things when you + + align:start position:0% +you know these type of things when you + + + align:start position:0% +you know these type of things when you +call for your computer and typically + + align:start position:0% +call for your computer and typically + + + align:start position:0% +call for your computer and typically +it's a nice young person from + + align:start position:0% +it's a nice young person from + + + align:start position:0% +it's a nice young person from +uh suburb of the universe suburb is + + align:start position:0% +uh suburb of the universe suburb is + + + align:start position:0% +uh suburb of the universe suburb is +intended in a very broad sense who is + + align:start position:0% +intended in a very broad sense who is + + + align:start position:0% +intended in a very broad sense who is +answering the phone + + align:start position:0% +answering the phone + + + align:start position:0% +answering the phone +um so early on they were really uh + + align:start position:0% +um so early on they were really uh + + + align:start position:0% +um so early on they were really uh +recruiting Muslim Gorgan very close to + + align:start position:0% +recruiting Muslim Gorgan very close to + + + align:start position:0% +recruiting Muslim Gorgan very close to +Delhi and then + + align:start position:0% +Delhi and then + + + align:start position:0% +Delhi and then +they started extending and he worked he + + align:start position:0% +they started extending and he worked he + + + align:start position:0% +they started extending and he worked he +worked with them at the beginning of + + align:start position:0% +worked with them at the beginning of + + + align:start position:0% +worked with them at the beginning of +expansion to kind of lead them to + + align:start position:0% +expansion to kind of lead them to + + + align:start position:0% +expansion to kind of lead them to +Villages where they had never been + + align:start position:0% +Villages where they had never been + + + align:start position:0% +Villages where they had never been +in haryana or in up so basically a + + align:start position:0% +in haryana or in up so basically a + + + align:start position:0% +in haryana or in up so basically a +broader sector around up + + align:start position:0% + + + + align:start position:0% + +um it connects the the the the + + align:start position:0% +um it connects the the the the + + + align:start position:0% +um it connects the the the the +BPO the ecosystem back office processing + + align:start position:0% +BPO the ecosystem back office processing + + + align:start position:0% +BPO the ecosystem back office processing +operation with with the Villagers + + align:start position:0% +operation with with the Villagers + + + align:start position:0% +operation with with the Villagers +someone goes to the Village advertises + + align:start position:0% +someone goes to the Village advertises + + + align:start position:0% +someone goes to the Village advertises +the possibility + + align:start position:0% +the possibility + + + align:start position:0% +the possibility +uh and then + + align:start position:0% +uh and then + + + align:start position:0% +uh and then +um sees what what happens so some girls + + align:start position:0% +um sees what what happens so some girls + + + align:start position:0% +um sees what what happens so some girls +who were at the right age and had the + + align:start position:0% +who were at the right age and had the + + + align:start position:0% +who were at the right age and had the +right education which is secondary + + align:start position:0% +right education which is secondary + + + align:start position:0% +right education which is secondary +education with some English went + + align:start position:0% +education with some English went + + + align:start position:0% +education with some English went +uh and he's interested in what happened + + align:start position:0% +uh and he's interested in what happened + + + align:start position:0% +uh and he's interested in what happened +to the younger girls uh + + align:start position:0% +to the younger girls uh + + + align:start position:0% +to the younger girls uh +who could not go yet they were little + + align:start position:0% +who could not go yet they were little + + + align:start position:0% +who could not go yet they were little +and they're more likely to stay in + + align:start position:0% +and they're more likely to stay in + + + align:start position:0% +and they're more likely to stay in +school + + align:start position:0% +school + + + align:start position:0% +school +so what he finds is that + + align:start position:0% +so what he finds is that + + + align:start position:0% +so what he finds is that +women are indeed a younger women are + + align:start position:0% +women are indeed a younger women are + + + align:start position:0% +women are indeed a younger women are +indeed more likely to be working in a + + align:start position:0% +indeed more likely to be working in a + + + align:start position:0% +indeed more likely to be working in a +BPO so that's that's good there was no + + align:start position:0% +BPO so that's that's good there was no + + + align:start position:0% +BPO so that's that's good there was no +such effect for men + + align:start position:0% +such effect for men + + + align:start position:0% +such effect for men +ah + + align:start position:0% +ah + + + align:start position:0% +ah +and that both younger and both this + + align:start position:0% +and that both younger and both this + + + align:start position:0% +and that both younger and both this +woman but also the younger woman + + align:start position:0% +woman but also the younger woman + + + align:start position:0% +woman but also the younger woman +the girls were more likely to be uh in + + align:start position:0% +the girls were more likely to be uh in + + + align:start position:0% +the girls were more likely to be uh in +school + + align:start position:0% +school + + + align:start position:0% +school +and even the even younger are better fed + + align:start position:0% + + + + align:start position:0% + +so basically the parents the story is + + align:start position:0% +so basically the parents the story is + + + align:start position:0% +so basically the parents the story is +parents realized that there is more + + align:start position:0% +parents realized that there is more + + + align:start position:0% +parents realized that there is more +returns to girls in general they become + + align:start position:0% +returns to girls in general they become + + + align:start position:0% +returns to girls in general they become +more valuable in general and in + + align:start position:0% +more valuable in general and in + + + align:start position:0% +more valuable in general and in +particular more valuable if they are + + align:start position:0% +particular more valuable if they are + + + align:start position:0% +particular more valuable if they are +educated so the return to education for + + align:start position:0% +educated so the return to education for + + + align:start position:0% +educated so the return to education for +women have gone up and they start + + align:start position:0% +women have gone up and they start + + + align:start position:0% +women have gone up and they start +educating them more + + align:start position:0% +educating them more + + + align:start position:0% +educating them more +so interestingly there is no effect for + + align:start position:0% +so interestingly there is no effect for + + + align:start position:0% +so interestingly there is no effect for +men it's not discussed much in these + + align:start position:0% +men it's not discussed much in these + + + align:start position:0% +men it's not discussed much in these +people but I have another paper where + + align:start position:0% +people but I have another paper where + + + align:start position:0% +people but I have another paper where +they separate the boys between people + + align:start position:0% +they separate the boys between people + + + align:start position:0% +they separate the boys between people +who at Baseline were described to be the + + align:start position:0% +who at Baseline were described to be the + + + align:start position:0% +who at Baseline were described to be the +one who are going to take care of the + + align:start position:0% +one who are going to take care of the + + + align:start position:0% +one who are going to take care of the +family farm so usually the oldest Boy + + align:start position:0% +family farm so usually the oldest Boy + + + align:start position:0% +family farm so usually the oldest Boy +versus the younger boy and when they + + align:start position:0% +versus the younger boy and when they + + + align:start position:0% +versus the younger boy and when they +separate that they find that actually + + align:start position:0% +separate that they find that actually + + + align:start position:0% +separate that they find that actually +when the BPO recruitment started for the + + align:start position:0% +when the BPO recruitment started for the + + + align:start position:0% +when the BPO recruitment started for the +boys who are supposed to work in the + + align:start position:0% +boys who are supposed to work in the + + + align:start position:0% +boys who are supposed to work in the +Family Farm + + align:start position:0% +Family Farm + + + align:start position:0% +Family Farm +the education went down + + align:start position:0% +the education went down + + + align:start position:0% +the education went down +and for other boys it's more like girls + + align:start position:0% +and for other boys it's more like girls + + + align:start position:0% +and for other boys it's more like girls +and so the idea there is that you're + + align:start position:0% +and so the idea there is that you're + + + align:start position:0% +and so the idea there is that you're +very scared to have returned to + + align:start position:0% +very scared to have returned to + + + align:start position:0% +very scared to have returned to +education go up for the boys because you + + align:start position:0% +education go up for the boys because you + + + align:start position:0% +education go up for the boys because you +don't want them to leave because someone + + align:start position:0% +don't want them to leave because someone + + + align:start position:0% +don't want them to leave because someone +needs to stay + + align:start position:0% +needs to stay + + + align:start position:0% +needs to stay +to take care of you and to take care of + + align:start position:0% +to take care of you and to take care of + + + align:start position:0% +to take care of you and to take care of +the farm and therefore you're going to + + align:start position:0% +the farm and therefore you're going to + + + align:start position:0% +the farm and therefore you're going to +surprise education so that they don't + + align:start position:0% +surprise education so that they don't + + + align:start position:0% +surprise education so that they don't +you know hear the return to education + + align:start position:0% +you know hear the return to education + + + align:start position:0% +you know hear the return to education +for you are a negative from the point of + + align:start position:0% +for you are a negative from the point of + + + align:start position:0% +for you are a negative from the point of +view of the parents so that leads a + + align:start position:0% +view of the parents so that leads a + + + align:start position:0% +view of the parents so that leads a +little bit to the conversation we had + + align:start position:0% +little bit to the conversation we had + + + align:start position:0% +little bit to the conversation we had +with uh and others about the contract + + align:start position:0% +with uh and others about the contract + + + align:start position:0% +with uh and others about the contract +between the family + + align:start position:0% +between the family + + + align:start position:0% +between the family +as if you cannot contract to get the + + align:start position:0% +as if you cannot contract to get the + + + align:start position:0% +as if you cannot contract to get the +money back from your board and you are + + align:start position:0% +money back from your board and you are + + + align:start position:0% +money back from your board and you are +not sending them + + align:start position:0% +not sending them + + + align:start position:0% +not sending them +um + + align:start position:0% + + + + align:start position:0% + +okay so there are there are two other + + align:start position:0% +okay so there are there are two other + + + align:start position:0% +okay so there are there are two other +things that I wanted to do that I didn't + + align:start position:0% +things that I wanted to do that I didn't + + + align:start position:0% +things that I wanted to do that I didn't +have time to do one of them I'll do + + align:start position:0% +have time to do one of them I'll do + + + align:start position:0% +have time to do one of them I'll do +later uh the when we talk about the + + align:start position:0% +later uh the when we talk about the + + + align:start position:0% +later uh the when we talk about the +family that's fine we can we can take + + align:start position:0% +family that's fine we can we can take + + + align:start position:0% +family that's fine we can we can take +that that's the Rebecca Addison Ross + + align:start position:0% +that that's the Rebecca Addison Ross + + + align:start position:0% +that that's the Rebecca Addison Ross +paper about the fact that parents have + + align:start position:0% +paper about the fact that parents have + + + align:start position:0% +paper about the fact that parents have +no idea what their kids are up to + + align:start position:0% +no idea what their kids are up to + + + align:start position:0% +no idea what their kids are up to +but this one I want to briefly uh + + align:start position:0% +but this one I want to briefly uh + + + align:start position:0% +but this one I want to briefly uh +mention + + align:start position:0% +mention + + + align:start position:0% +mention +it's a paper by uh simaja Sandra and + + align:start position:0% +it's a paper by uh simaja Sandra and + + + align:start position:0% +it's a paper by uh simaja Sandra and +Adriana erasmune + + align:start position:0% +Adriana erasmune + + + align:start position:0% +Adriana erasmune +who is looking at another returned way + + align:start position:0% +who is looking at another returned way + + + align:start position:0% +who is looking at another returned way +of affecting the return to education or + + align:start position:0% +of affecting the return to education or + + + align:start position:0% +of affecting the return to education or +the where returns are affecting is + + align:start position:0% +the where returns are affecting is + + + align:start position:0% +the where returns are affecting is +simply the fact that how long are you + + align:start position:0% +simply the fact that how long are you + + + align:start position:0% +simply the fact that how long are you +going to live + + align:start position:0% +going to live + + + align:start position:0% +going to live +so if you expect to live for a very + + align:start position:0% +so if you expect to live for a very + + + align:start position:0% +so if you expect to live for a very +short period of time then your education + + align:start position:0% +short period of time then your education + + + align:start position:0% +short period of time then your education +is not very worth it or if you expect + + align:start position:0% +is not very worth it or if you expect + + + align:start position:0% +is not very worth it or if you expect +your girl to leave for a very short time + + align:start position:0% +your girl to leave for a very short time + + + align:start position:0% +your girl to leave for a very short time +because she's going to die in childbirth + + align:start position:0% +because she's going to die in childbirth + + + align:start position:0% +because she's going to die in childbirth +anywhere then you know she's not going + + align:start position:0% +anywhere then you know she's not going + + + align:start position:0% +anywhere then you know she's not going +to experience the return for a very + + align:start position:0% +to experience the return for a very + + + align:start position:0% +to experience the return for a very +short time so that's a very Economist + + align:start position:0% +short time so that's a very Economist + + + align:start position:0% +short time so that's a very Economist +Economist way to think but uh + + align:start position:0% +Economist way to think but uh + + + align:start position:0% +Economist way to think but uh +it is quite interesting that it works + + align:start position:0% +it is quite interesting that it works + + + align:start position:0% +it is quite interesting that it works +here so what they are looking for to + + align:start position:0% +here so what they are looking for to + + + align:start position:0% +here so what they are looking for to +know whether people so in principle + + align:start position:0% +know whether people so in principle + + + align:start position:0% +know whether people so in principle +implication of this model is that if + + align:start position:0% +implication of this model is that if + + + align:start position:0% +implication of this model is that if +people expect to live longer they should + + align:start position:0% +people expect to live longer they should + + + align:start position:0% +people expect to live longer they should +or expect their daughters to to live + + align:start position:0% +or expect their daughters to to live + + + align:start position:0% +or expect their daughters to to live +longer they should really educate them + + align:start position:0% +longer they should really educate them + + + align:start position:0% +longer they should really educate them +more because they're going to enjoy the + + align:start position:0% +more because they're going to enjoy the + + + align:start position:0% +more because they're going to enjoy the +return of this education over a longer + + align:start position:0% +return of this education over a longer + + + align:start position:0% +return of this education over a longer +time period + + align:start position:0% +time period + + + align:start position:0% +time period +so you'll know you need an instrument + + align:start position:0% +so you'll know you need an instrument + + + align:start position:0% +so you'll know you need an instrument +that affects the number of years someone + + align:start position:0% +that affects the number of years someone + + + align:start position:0% +that affects the number of years someone +can expect to live without affecting + + align:start position:0% +can expect to live without affecting + + + align:start position:0% +can expect to live without affecting +anything else like the skill premium or + + align:start position:0% +anything else like the skill premium or + + + align:start position:0% +anything else like the skill premium or +the low uh or the low skill wage which + + align:start position:0% +the low uh or the low skill wage which + + + align:start position:0% +the low uh or the low skill wage which +seems like a very hard problem + + align:start position:0% +seems like a very hard problem + + + align:start position:0% +seems like a very hard problem +and what they find is to is uh in Sri + + align:start position:0% +and what they find is to is uh in Sri + + + align:start position:0% +and what they find is to is uh in Sri +Lanka a program that introduces + + align:start position:0% +Lanka a program that introduces + + + align:start position:0% +Lanka a program that introduces +ambulance uh in in all the villages + + align:start position:0% +ambulance uh in in all the villages + + + align:start position:0% +ambulance uh in in all the villages +and when they did that + + align:start position:0% +and when they did that + + + align:start position:0% +and when they did that +uh infant mortality collapsed + + align:start position:0% +uh infant mortality collapsed + + + align:start position:0% +uh infant mortality collapsed +and I did that infant mortality + + align:start position:0% +and I did that infant mortality + + + align:start position:0% +and I did that infant mortality +collapsed and in particular the drop in + + align:start position:0% +collapsed and in particular the drop in + + + align:start position:0% +collapsed and in particular the drop in +infant mortality was much larger and + + align:start position:0% +infant mortality was much larger and + + + align:start position:0% +infant mortality was much larger and +places where infant maternity was very + + align:start position:0% +places where infant maternity was very + + + align:start position:0% +places where infant maternity was very +high so basically putting the ambulance + + align:start position:0% +high so basically putting the ambulance + + + align:start position:0% +high so basically putting the ambulance +flattened out the infant mortality curve + + align:start position:0% +flattened out the infant mortality curve + + + align:start position:0% +flattened out the infant mortality curve +leading to huge decline in infant + + align:start position:0% +leading to huge decline in infant + + + align:start position:0% +leading to huge decline in infant +mortality in places that were you know + + align:start position:0% +mortality in places that were you know + + + align:start position:0% +mortality in places that were you know +really far from the hospital and people + + align:start position:0% +really far from the hospital and people + + + align:start position:0% +really far from the hospital and people +couldn't get to the hospital so the + + align:start position:0% +couldn't get to the hospital so the + + + align:start position:0% +couldn't get to the hospital so the +ambulance kind of eliminated + + align:start position:0% +ambulance kind of eliminated + + + align:start position:0% +ambulance kind of eliminated +so now they use that in saying well that + + align:start position:0% +so now they use that in saying well that + + + align:start position:0% +so now they use that in saying well that +affects that affects the the life + + align:start position:0% +affects that affects the the life + + + align:start position:0% +affects that affects the the life +expectancy of the woman but not the men + + align:start position:0% +expectancy of the woman but not the men + + + align:start position:0% +expectancy of the woman but not the men +so now I'm going to use basically the + + align:start position:0% +so now I'm going to use basically the + + + align:start position:0% +so now I'm going to use basically the +pre ambulance maternal mortality rate as + + align:start position:0% +pre ambulance maternal mortality rate as + + + align:start position:0% +pre ambulance maternal mortality rate as +an instrument for the decline in + + align:start position:0% +an instrument for the decline in + + + align:start position:0% +an instrument for the decline in +maternal mortality rate over the period + + align:start position:0% +maternal mortality rate over the period + + + align:start position:0% +maternal mortality rate over the period +to see whether people seem to respond by + + align:start position:0% +to see whether people seem to respond by + + + align:start position:0% +to see whether people seem to respond by +by educating their their girls more + + align:start position:0% +by educating their their girls more + + + align:start position:0% +by educating their their girls more +relative to the boy + + align:start position:0% +relative to the boy + + + align:start position:0% +relative to the boy +so now what we have here is a triple + + align:start position:0% +so now what we have here is a triple + + + align:start position:0% +so now what we have here is a triple +different specification + + align:start position:0% +different specification + + + align:start position:0% +different specification +and I just write down put the + + align:start position:0% +and I just write down put the + + + align:start position:0% +and I just write down put the +specification down + + align:start position:0% +specification down + + + align:start position:0% +specification down +where we have we can have a fixed effect + + align:start position:0% +where we have we can have a fixed effect + + + align:start position:0% +where we have we can have a fixed effect +we can have two effects effect whichever + + align:start position:0% +we can have two effects effect whichever + + + align:start position:0% +we can have two effects effect whichever +way District uh year District time here + + align:start position:0% +way District uh year District time here + + + align:start position:0% +way District uh year District time here +and + + align:start position:0% +and + + + align:start position:0% +and +um gender time district and gender time + + align:start position:0% +um gender time district and gender time + + + align:start position:0% +um gender time district and gender time +year so all of the double interaction + + align:start position:0% +year so all of the double interaction + + + align:start position:0% +year so all of the double interaction +can be there because what we are going + + align:start position:0% +can be there because what we are going + + + align:start position:0% +can be there because what we are going +to use is maternal mortality + + align:start position:0% +to use is maternal mortality + + + align:start position:0% +to use is maternal mortality +in a particular year like the time when + + align:start position:0% +in a particular year like the time when + + + align:start position:0% +in a particular year like the time when +they were on the you know when the + + align:start position:0% +they were on the you know when the + + + align:start position:0% +they were on the you know when the +parents could observe it times the + + align:start position:0% +parents could observe it times the + + + align:start position:0% +parents could observe it times the +female the + + align:start position:0% +female the + + + align:start position:0% +female the +and I find the uh they find that more + + align:start position:0% +and I find the uh they find that more + + + align:start position:0% +and I find the uh they find that more +maternal mortality less education + + align:start position:0% + + + + align:start position:0% + +so using just that + + align:start position:0% +so using just that + + + align:start position:0% +so using just that +they find that more maternal mortality + + align:start position:0% +they find that more maternal mortality + + + align:start position:0% +they find that more maternal mortality +leads to less education so that's kind + + align:start position:0% +leads to less education so that's kind + + + align:start position:0% +leads to less education so that's kind +of a nice paper because I think many + + align:start position:0% +of a nice paper because I think many + + + align:start position:0% +of a nice paper because I think many +people were kind of entreating that + + align:start position:0% +people were kind of entreating that + + + align:start position:0% +people were kind of entreating that +something like that might be going on + + align:start position:0% +something like that might be going on + + + align:start position:0% +something like that might be going on +but since everything is usually + + align:start position:0% +but since everything is usually + + + align:start position:0% +but since everything is usually +correlated with everything it's very + + align:start position:0% +correlated with everything it's very + + + align:start position:0% +correlated with everything it's very +hard to test and it's like ambulance + + align:start position:0% +hard to test and it's like ambulance + + + align:start position:0% +hard to test and it's like ambulance +program that was that had such a massive + + align:start position:0% +program that was that had such a massive + + + align:start position:0% +program that was that had such a massive +effect on maternal material mortality + + align:start position:0% +effect on maternal material mortality + + + align:start position:0% +effect on maternal material mortality +reduction gave them a chance to to test + + align:start position:0% +reduction gave them a chance to to test + + + align:start position:0% +reduction gave them a chance to to test +the idea + + align:start position:0% +the idea + + + align:start position:0% +the idea +right so sorry uh so we're done for + + align:start position:0% +right so sorry uh so we're done for + + + align:start position:0% +right so sorry uh so we're done for +today sorry again for uh + + align:start position:0% +today sorry again for uh + + + align:start position:0% +today sorry again for uh +slow start and uh on Monday we'll + + align:start position:0% +slow start and uh on Monday we'll + + + align:start position:0% +slow start and uh on Monday we'll +continue talking about the Indonesia + + align:start position:0% +continue talking about the Indonesia + + + align:start position:0% +continue talking about the Indonesia +paper but we'll talk about this + + align:start position:0% +paper but we'll talk about this + + + align:start position:0% +paper but we'll talk about this +estimating the return to education we + + align:start position:0% +estimating the return to education we + + + align:start position:0% +estimating the return to education we +also talk about the Ghana paper which + + align:start position:0% +also talk about the Ghana paper which + + + align:start position:0% +also talk about the Ghana paper which +I'm asking you to read as you go along + + align:start position:0% +I'm asking you to read as you go along + + + align:start position:0% +I'm asking you to read as you go along +which is another + + align:start position:0% +which is another + + + align:start position:0% +which is another +take at estimating return to education + + align:start position:0% +take at estimating return to education + + + align:start position:0% +take at estimating return to education +or impact of Education \ No newline at end of file diff --git a/NcPUI7aPFhA.txt b/NcPUI7aPFhA.txt new file mode 100644 index 0000000000000000000000000000000000000000..5a3600d998a710693fc14db460861d75094be1be --- /dev/null +++ b/NcPUI7aPFhA.txt @@ -0,0 +1,6219 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT OpenCourseWare continue to + + align:start position:0% +will help MIT OpenCourseWare continue to + + + align:start position:0% +will help MIT OpenCourseWare continue to +offer high quality educational resources + + align:start position:0% +offer high quality educational resources + + + align:start position:0% +offer high quality educational resources +for free + + align:start position:0% +for free + + + align:start position:0% +for free +to make a donation or to view additional + + align:start position:0% +to make a donation or to view additional + + + align:start position:0% +to make a donation or to view additional +materials from hundreds of MIT courses + + align:start position:0% +materials from hundreds of MIT courses + + + align:start position:0% +materials from hundreds of MIT courses +visit MIT opencourseware at ocw.mit.edu + + align:start position:0% + + + + align:start position:0% + +okay so this big MIT I just came from a + + align:start position:0% +okay so this big MIT I just came from a + + + align:start position:0% +okay so this big MIT I just came from a +faculty terrific faculty member Andy low + + align:start position:0% +faculty terrific faculty member Andy low + + + align:start position:0% +faculty terrific faculty member Andy low +in in the Sloan School and I have to + + align:start position:0% +in in the Sloan School and I have to + + + align:start position:0% +in in the Sloan School and I have to +tell you what he told us and then I had + + align:start position:0% +tell you what he told us and then I had + + + align:start position:0% +tell you what he told us and then I had +I had to leave before he could explain + + align:start position:0% +I had to leave before he could explain + + + align:start position:0% +I had to leave before he could explain +why it's true but this is like an + + align:start position:0% +why it's true but this is like an + + + align:start position:0% +why it's true but this is like an +amazing fact which I don't want to + + align:start position:0% +amazing fact which I don't want to + + + align:start position:0% +amazing fact which I don't want to +forget so here you go this is everything + + align:start position:0% +forget so here you go this is everything + + + align:start position:0% +forget so here you go this is everything +will be on that board so it's it's it's + + align:start position:0% +will be on that board so it's it's it's + + + align:start position:0% +will be on that board so it's it's it's +an observation about us or other people + + align:start position:0% +an observation about us or other people + + + align:start position:0% +an observation about us or other people +maybe not us but so suppose you have a + + align:start position:0% +maybe not us but so suppose you have a + + + align:start position:0% +maybe not us but so suppose you have a +biased coin maybe you don't the people + + align:start position:0% +biased coin maybe you don't the people + + + align:start position:0% +biased coin maybe you don't the people +playing this game don't know but it's + + align:start position:0% +playing this game don't know but it's + + + align:start position:0% +playing this game don't know but it's +75% likely to produce heads 25% likely + + align:start position:0% +75% likely to produce heads 25% likely + + + align:start position:0% +75% likely to produce heads 25% likely +to produce tails and then the player has + + align:start position:0% +to produce tails and then the player has + + + align:start position:0% +to produce tails and then the player has +to guess for one flip after another + + align:start position:0% +to guess for one flip after another + + + align:start position:0% +to guess for one flip after another +heads or tails and you get a dollar if + + align:start position:0% +heads or tails and you get a dollar if + + + align:start position:0% +heads or tails and you get a dollar if +you're right you pay a dollar if you're + + align:start position:0% +you're right you pay a dollar if you're + + + align:start position:0% +you're right you pay a dollar if you're +wrong so you just want to get as many + + align:start position:0% +wrong so you just want to get as many + + + align:start position:0% +wrong so you just want to get as many +right choices as possible from this coin + + align:start position:0% +right choices as possible from this coin + + + align:start position:0% +right choices as possible from this coin +flip that continues so what should you + + align:start position:0% +flip that continues so what should you + + + align:start position:0% +flip that continues so what should you +do well what I guess I hope we would do + + align:start position:0% +do well what I guess I hope we would do + + + align:start position:0% +do well what I guess I hope we would do +is we would not know what the + + align:start position:0% +is we would not know what the + + + align:start position:0% +is we would not know what the +probabilities were so we would guess + + align:start position:0% +probabilities were so we would guess + + + align:start position:0% +probabilities were so we would guess +maybe heads the first time tails the + + align:start position:0% +maybe heads the first time tails the + + + align:start position:0% +maybe heads the first time tails the +second time heads to the third time and + + align:start position:0% +second time heads to the third time and + + + align:start position:0% +second time heads to the third time and +so on but the actual result would be + + align:start position:0% +so on but the actual result would be + + + align:start position:0% +so on but the actual result would be +mostly heads + + align:start position:0% +mostly heads + + + align:start position:0% +mostly heads +so we would learn at some point that + + align:start position:0% +so we would learn at some point that + + + align:start position:0% +so we would learn at some point that +maybe maybe not quite as soon as that we + + align:start position:0% +maybe maybe not quite as soon as that we + + + align:start position:0% +maybe maybe not quite as soon as that we +would eventually learn that we should + + align:start position:0% +would eventually learn that we should + + + align:start position:0% +would eventually learn that we should +keep guessing heads right and then we + + align:start position:0% +keep guessing heads right and then we + + + align:start position:0% +keep guessing heads right and then we +would be that would be our optimal + + align:start position:0% +would be that would be our optimal + + + align:start position:0% +would be that would be our optimal +strategy to guess heads all the time but + + align:start position:0% +strategy to guess heads all the time but + + + align:start position:0% +strategy to guess heads all the time but +what do people actually do they do start + + align:start position:0% +what do people actually do they do start + + + align:start position:0% +what do people actually do they do start +like this same way and then they're + + align:start position:0% +like this same way and then they're + + + align:start position:0% +like this same way and then they're +beginning to learn that heads is more + + align:start position:0% +beginning to learn that heads is more + + + align:start position:0% +beginning to learn that heads is more +common so maybe they do more heads than + + align:start position:0% +common so maybe they do more heads than + + + align:start position:0% +common so maybe they do more heads than +tails but sometimes tails is right and + + align:start position:0% +tails but sometimes tails is right and + + + align:start position:0% +tails but sometimes tails is right and +then after a little while they maybe see + + align:start position:0% +then after a little while they maybe see + + + align:start position:0% +then after a little while they maybe see +that it's yeah or they're just well + + align:start position:0% +that it's yeah or they're just well + + + align:start position:0% +that it's yeah or they're just well +maybe they're not counting they're just + + align:start position:0% +maybe they're not counting they're just + + + align:start position:0% +maybe they're not counting they're just +like operating like ordinary people + + align:start position:0% +like operating like ordinary people + + + align:start position:0% +like operating like ordinary people +and what do ordinary people actually do + + align:start position:0% +and what do ordinary people actually do + + + align:start position:0% +and what do ordinary people actually do +in the long run you would say guess + + align:start position:0% +in the long run you would say guess + + + align:start position:0% +in the long run you would say guess +heads every time right but they don't in + + align:start position:0% +heads every time right but they don't in + + + align:start position:0% +heads every time right but they don't in +the long run people and maybe animals + + align:start position:0% +the long run people and maybe animals + + + align:start position:0% +the long run people and maybe animals +and whatever guess heads three-quarters + + align:start position:0% +and whatever guess heads three-quarters + + + align:start position:0% +and whatever guess heads three-quarters +of the time and tails one quarter at a + + align:start position:0% +of the time and tails one quarter at a + + + align:start position:0% +of the time and tails one quarter at a +time isn't that unbelievable they're + + align:start position:0% +time isn't that unbelievable they're + + + align:start position:0% +time isn't that unbelievable they're +guessing tails a quarter of the time + + align:start position:0% +guessing tails a quarter of the time + + + align:start position:0% +guessing tails a quarter of the time +when the odds are never changing anyway + + align:start position:0% +when the odds are never changing anyway + + + align:start position:0% +when the odds are never changing anyway +that's that's something that economists + + align:start position:0% +that's that's something that economists + + + align:start position:0% +that's that's something that economists +and and other people have to explain and + + align:start position:0% +and and other people have to explain and + + + align:start position:0% +and and other people have to explain and +if I had been able to stay another hour + + align:start position:0% +if I had been able to stay another hour + + + align:start position:0% +if I had been able to stay another hour +I could tell you about the explanation + + align:start position:0% +I could tell you about the explanation + + + align:start position:0% +I could tell you about the explanation +but anyway that's that's I I see I've + + align:start position:0% +but anyway that's that's I I see I've + + + align:start position:0% +but anyway that's that's I I see I've +written that on a board that I have no + + align:start position:0% +written that on a board that I have no + + + align:start position:0% +written that on a board that I have no +way to bury so it's gonna be there and + + align:start position:0% +way to bury so it's gonna be there and + + + align:start position:0% +way to bury so it's gonna be there and +it's not the subject of 1806 five but + + align:start position:0% +it's not the subject of 1806 five but + + + align:start position:0% +it's not the subject of 1806 five but +it's kind of amazing right so there's + + align:start position:0% +it's kind of amazing right so there's + + + align:start position:0% +it's kind of amazing right so there's +good math problems everywhere okay can I + + align:start position:0% +good math problems everywhere okay can I + + + align:start position:0% +good math problems everywhere okay can I +just leave you with what I know and and + + align:start position:0% +just leave you with what I know and and + + + align:start position:0% +just leave you with what I know and and +if I learn more I'll come back to that + + align:start position:0% +if I learn more I'll come back to that + + + align:start position:0% +if I learn more I'll come back to that +question okay + + align:start position:0% +question okay + + + align:start position:0% +question okay +please turn attention this way right + + align:start position:0% +please turn attention this way right + + + align:start position:0% +please turn attention this way right +Norm's a little a few words on norms + + align:start position:0% +Norm's a little a few words on norms + + + align:start position:0% +Norm's a little a few words on norms +just like that should be a word in your + + align:start position:0% +just like that should be a word in your + + + align:start position:0% +just like that should be a word in your +language and so you should know what it + + align:start position:0% +language and so you should know what it + + + align:start position:0% +language and so you should know what it +mean and you should know they're a few + + align:start position:0% +mean and you should know they're a few + + + align:start position:0% +mean and you should know they're a few +of the important norms again a norm is a + + align:start position:0% +of the important norms again a norm is a + + + align:start position:0% +of the important norms again a norm is a +way to measure the size of a vector or + + align:start position:0% +way to measure the size of a vector or + + + align:start position:0% +way to measure the size of a vector or +the size of a matrix or the size of a + + align:start position:0% +the size of a matrix or the size of a + + + align:start position:0% +the size of a matrix or the size of a +tensor whatever we have or a function + + align:start position:0% +tensor whatever we have or a function + + + align:start position:0% +tensor whatever we have or a function +very important the norm would be a + + align:start position:0% +very important the norm would be a + + + align:start position:0% +very important the norm would be a +function like sine X from zero to PI + + align:start position:0% +function like sine X from zero to PI + + + align:start position:0% +function like sine X from zero to PI +what would be the size of that function + + align:start position:0% +what would be the size of that function + + + align:start position:0% +what would be the size of that function +well if it was two sine x the size would + + align:start position:0% +well if it was two sine x the size would + + + align:start position:0% +well if it was two sine x the size would +be twice as much so the norm should + + align:start position:0% +be twice as much so the norm should + + + align:start position:0% +be twice as much so the norm should +reflect that but so yesterday or + + align:start position:0% +reflect that but so yesterday or + + + align:start position:0% +reflect that but so yesterday or +Wednesday I told you the so there P + + align:start position:0% +Wednesday I told you the so there P + + + align:start position:0% +Wednesday I told you the so there P +equals to 1 actually infinity and then + + align:start position:0% +equals to 1 actually infinity and then + + + align:start position:0% +equals to 1 actually infinity and then +I'm gonna put in the zero norm with a + + align:start position:0% +I'm gonna put in the zero norm with a + + + align:start position:0% +I'm gonna put in the zero norm with a +question mark because you'll see it's + + align:start position:0% +question mark because you'll see it's + + + align:start position:0% +question mark because you'll see it's +that it has a problem but let me just + + align:start position:0% +that it has a problem but let me just + + + align:start position:0% +that it has a problem but let me just +recall from last time so these are the P + + align:start position:0% +recall from last time so these are the P + + + align:start position:0% +recall from last time so these are the P +equal to two is the usual sum of squares + + align:start position:0% +equal to two is the usual sum of squares + + + align:start position:0% +equal to two is the usual sum of squares +square root usual length of a vector P + + align:start position:0% +square root usual length of a vector P + + + align:start position:0% +square root usual length of a vector P +equal one is this very important norm so + + align:start position:0% +equal one is this very important norm so + + + align:start position:0% +equal one is this very important norm so +a we call that the l1 norm and we'll see + + align:start position:0% +a we call that the l1 norm and we'll see + + + align:start position:0% +a we call that the l1 norm and we'll see +a lot of that that really I mentioned + + align:start position:0% +a lot of that that really I mentioned + + + align:start position:0% +a lot of that that really I mentioned +that it plays a very significant part + + align:start position:0% +that it plays a very significant part + + + align:start position:0% +that it plays a very significant part +now in compress sensing it really was a + + align:start position:0% +now in compress sensing it really was a + + + align:start position:0% +now in compress sensing it really was a +bombshell in signal processing to + + align:start position:0% +bombshell in signal processing to + + + align:start position:0% +bombshell in signal processing to +discover and in other fields to to + + align:start position:0% +discover and in other fields to to + + + align:start position:0% +discover and in other fields to to +discover that some things really work + + align:start position:0% +discover that some things really work + + + align:start position:0% +discover that some things really work +well work best in the l1 norm the + + align:start position:0% +well work best in the l1 norm the + + + align:start position:0% +well work best in the l1 norm the +maximum norm has a natural part to play + + align:start position:0% +maximum norm has a natural part to play + + + align:start position:0% +maximum norm has a natural part to play +and we'll see that or its matrix analog + + align:start position:0% +and we'll see that or its matrix analog + + + align:start position:0% +and we'll see that or its matrix analog +so I didn't mention the l0 norm all this + + align:start position:0% +so I didn't mention the l0 norm all this + + + align:start position:0% +so I didn't mention the l0 norm all this +LP business so the LP norm + + align:start position:0% +LP business so the LP norm + + + align:start position:0% +LP business so the LP norm +or for any P is you take the piece power + + align:start position:0% + + + + align:start position:0% + +to the piece power up here P was 2 and + + align:start position:0% +to the piece power up here P was 2 and + + + align:start position:0% +to the piece power up here P was 2 and +your take the piece root so maybe I + + align:start position:0% +your take the piece root so maybe I + + + align:start position:0% +your take the piece root so maybe I +should write it to the one over P that's + + align:start position:0% +should write it to the one over P that's + + + align:start position:0% +should write it to the one over P that's +then that way + + align:start position:0% +then that way + + + align:start position:0% +then that way +taking piece powers and piece roots we + + align:start position:0% +taking piece powers and piece roots we + + + align:start position:0% +taking piece powers and piece roots we +do get the norm of two V has a factor + + align:start position:0% +do get the norm of two V has a factor + + + align:start position:0% +do get the norm of two V has a factor +two compared to the norm of V so P equal + + align:start position:0% +two compared to the norm of V so P equal + + + align:start position:0% +two compared to the norm of V so P equal +to 2 you see that we've got it right + + align:start position:0% +to 2 you see that we've got it right + + + align:start position:0% +to 2 you see that we've got it right +there P equal one you see it here + + align:start position:0% +there P equal one you see it here + + + align:start position:0% +there P equal one you see it here +because it's just just sum of the + + align:start position:0% +because it's just just sum of the + + + align:start position:0% +because it's just just sum of the +absolute values people infinity if I if + + align:start position:0% +absolute values people infinity if I if + + + align:start position:0% +absolute values people infinity if I if +I move P up and up and up it will pick + + align:start position:0% +I move P up and up and up it will pick + + + align:start position:0% +I move P up and up and up it will pick +out you know as I increase P whichever + + align:start position:0% +out you know as I increase P whichever + + + align:start position:0% +out you know as I increase P whichever +one is biggest is going to just take + + align:start position:0% +one is biggest is going to just take + + + align:start position:0% +one is biggest is going to just take +over and that's why you get to max norm + + align:start position:0% +over and that's why you get to max norm + + + align:start position:0% +over and that's why you get to max norm +now there's zero norm where I'm using + + align:start position:0% +now there's zero norm where I'm using + + + align:start position:0% +now there's zero norm where I'm using +that word like improperly as you'll see + + align:start position:0% +that word like improperly as you'll see + + + align:start position:0% +that word like improperly as you'll see +because if so what is the 0 norm it's + + align:start position:0% +because if so what is the 0 norm it's + + + align:start position:0% +because if so what is the 0 norm it's +the so so it's the number of non-zeros + + align:start position:0% +the so so it's the number of non-zeros + + + align:start position:0% +the so so it's the number of non-zeros +of nonzero components its it it's the + + align:start position:0% +of nonzero components its it it's the + + + align:start position:0% +of nonzero components its it it's the +thing that you'd like to know about in + + align:start position:0% +thing that you'd like to know about in + + + align:start position:0% +thing that you'd like to know about in +question of sparsity does the is there + + align:start position:0% +question of sparsity does the is there + + + align:start position:0% +question of sparsity does the is there +just one nonzero component or there 11 + + align:start position:0% +just one nonzero component or there 11 + + + align:start position:0% +just one nonzero component or there 11 +are there 101 like what that you might + + align:start position:0% +are there 101 like what that you might + + + align:start position:0% +are there 101 like what that you might +want to minimize that because sparse + + align:start position:0% +want to minimize that because sparse + + + align:start position:0% +want to minimize that because sparse +vectors and sparse matrices are much + + align:start position:0% +vectors and sparse matrices are much + + + align:start position:0% +vectors and sparse matrices are much +faster to compute with you've got good + + align:start position:0% +faster to compute with you've got good + + + align:start position:0% +faster to compute with you've got good +stuff but now i claim that's not a norm + + align:start position:0% +stuff but now i claim that's not a norm + + + align:start position:0% +stuff but now i claim that's not a norm +in the number of 0 nonzero components + + align:start position:0% +in the number of 0 nonzero components + + + align:start position:0% +in the number of 0 nonzero components +because what's the norm of to how does + + align:start position:0% +because what's the norm of to how does + + + align:start position:0% +because what's the norm of to how does +the norm of 2v compare with the norm of + + align:start position:0% +the norm of 2v compare with the norm of + + + align:start position:0% +the norm of 2v compare with the norm of +V the 0 norm it would be the same to V + + align:start position:0% +V the 0 norm it would be the same to V + + + align:start position:0% +V the 0 norm it would be the same to V +has the same number of non-zeros as + + align:start position:0% +has the same number of non-zeros as + + + align:start position:0% +has the same number of non-zeros as +so it violates the rule for a norm so I + + align:start position:0% +so it violates the rule for a norm so I + + + align:start position:0% +so it violates the rule for a norm so I +think with these norms and all the peas + + align:start position:0% +think with these norms and all the peas + + + align:start position:0% +think with these norms and all the peas +in between so actually the the math + + align:start position:0% +in between so actually the the math + + + align:start position:0% +in between so actually the the math +papers are full of let P be between 1 + + align:start position:0% +papers are full of let P be between 1 + + + align:start position:0% +papers are full of let P be between 1 +and infinity and because that's the + + align:start position:0% +and infinity and because that's the + + + align:start position:0% +and infinity and because that's the +range where you do have a proper norm as + + align:start position:0% +range where you do have a proper norm as + + + align:start position:0% +range where you do have a proper norm as +we will see I think the good thing to do + + align:start position:0% +we will see I think the good thing to do + + + align:start position:0% +we will see I think the good thing to do +with these norms is to have a picture in + + align:start position:0% +with these norms is to have a picture in + + + align:start position:0% +with these norms is to have a picture in +your mind the geometry of a norm is real + + align:start position:0% +your mind the geometry of a norm is real + + + align:start position:0% +your mind the geometry of a norm is real +is good so the picture I'm gonna suggest + + align:start position:0% +is good so the picture I'm gonna suggest + + + align:start position:0% +is good so the picture I'm gonna suggest +is plot all the vectors let's say in 2d + + align:start position:0% +is plot all the vectors let's say in 2d + + + align:start position:0% +is plot all the vectors let's say in 2d +so two dimensional space or two so I + + align:start position:0% +so two dimensional space or two so I + + + align:start position:0% +so two dimensional space or two so I +want to plot then the vectors they have + + align:start position:0% +want to plot then the vectors they have + + + align:start position:0% +want to plot then the vectors they have +V equal one in these different norms so + + align:start position:0% +V equal one in these different norms so + + + align:start position:0% +V equal one in these different norms so +let me ask you what so here's 2d space + + align:start position:0% +let me ask you what so here's 2d space + + + align:start position:0% +let me ask you what so here's 2d space +r2 and now I want to plot all the + + align:start position:0% +r2 and now I want to plot all the + + + align:start position:0% +r2 and now I want to plot all the +vectors that have the ordinary l2 + + align:start position:0% +vectors that have the ordinary l2 + + + align:start position:0% +vectors that have the ordinary l2 +lengths equal one so what does that + + align:start position:0% +lengths equal one so what does that + + + align:start position:0% +lengths equal one so what does that +picture look like I just think a picture + + align:start position:0% +picture look like I just think a picture + + + align:start position:0% +picture look like I just think a picture +is really worth something it's a circle + + align:start position:0% +is really worth something it's a circle + + + align:start position:0% +is really worth something it's a circle +thanks it's a circle it's a circle this + + align:start position:0% +thanks it's a circle it's a circle this + + + align:start position:0% +thanks it's a circle it's a circle this +circle is that's the equation of course + + align:start position:0% +circle is that's the equation of course + + + align:start position:0% +circle is that's the equation of course +v1 squared plus v2 squared 1 so that I + + align:start position:0% +v1 squared plus v2 squared 1 so that I + + + align:start position:0% +v1 squared plus v2 squared 1 so that I +would call that the unit ball for the + + align:start position:0% +would call that the unit ball for the + + + align:start position:0% +would call that the unit ball for the +norm or whatever is is a circle okay now + + align:start position:0% +norm or whatever is is a circle okay now + + + align:start position:0% +norm or whatever is is a circle okay now +now here comes more interesting what + + align:start position:0% +now here comes more interesting what + + + align:start position:0% +now here comes more interesting what +about in the l1 so again tell me how to + + align:start position:0% +about in the l1 so again tell me how to + + + align:start position:0% +about in the l1 so again tell me how to +plot all the points that have V 1 plus V + + align:start position:0% +plot all the points that have V 1 plus V + + + align:start position:0% +plot all the points that have V 1 plus V +2 equal 1 what what what's the boundary + + align:start position:0% +2 equal 1 what what what's the boundary + + + align:start position:0% +2 equal 1 what what what's the boundary +gonna look like now it's gonna be let's + + align:start position:0% +gonna look like now it's gonna be let's + + + align:start position:0% +gonna look like now it's gonna be let's +see well I can put in a certain number + + align:start position:0% +see well I can put in a certain number + + + align:start position:0% +see well I can put in a certain number +of points there one and there one and + + align:start position:0% +of points there one and there one and + + + align:start position:0% +of points there one and there one and +there at minus one and there + + align:start position:0% +there at minus one and there + + + align:start position:0% +there at minus one and there +this one there was that would be the + + align:start position:0% +this one there was that would be the + + + align:start position:0% +this one there was that would be the +vector that would reflect the vector 1 0 + + align:start position:0% +vector that would reflect the vector 1 0 + + + align:start position:0% +vector that would reflect the vector 1 0 +and this would reflect the vector 0 + + align:start position:0% +and this would reflect the vector 0 + + + align:start position:0% +and this would reflect the vector 0 +minus 1 so yeah ok so those are like + + align:start position:0% +minus 1 so yeah ok so those are like + + + align:start position:0% +minus 1 so yeah ok so those are like +four points easy to plot easy to see + + align:start position:0% +four points easy to plot easy to see + + + align:start position:0% +four points easy to plot easy to see +that the l1 norm but what's the full + + align:start position:0% +that the l1 norm but what's the full + + + align:start position:0% +that the l1 norm but what's the full +what so what's the rest of the boundary + + align:start position:0% +what so what's the rest of the boundary + + + align:start position:0% +what so what's the rest of the boundary +here it's a diamond good it's a diamond + + align:start position:0% +here it's a diamond good it's a diamond + + + align:start position:0% +here it's a diamond good it's a diamond +it's we have linear set equal to one up + + align:start position:0% +it's we have linear set equal to one up + + + align:start position:0% +it's we have linear set equal to one up +here in the positive quadrant + + align:start position:0% +here in the positive quadrant + + + align:start position:0% +here in the positive quadrant +it's just V 1 plus V 2 equal 1 in the + + align:start position:0% +it's just V 1 plus V 2 equal 1 in the + + + align:start position:0% +it's just V 1 plus V 2 equal 1 in the +graph of that is a straight line so all + + align:start position:0% +graph of that is a straight line so all + + + align:start position:0% +graph of that is a straight line so all +these guys this is all the points with V + + align:start position:0% +these guys this is all the points with V + + + align:start position:0% +these guys this is all the points with V +1 plus V 2 equal 1 and over here and + + align:start position:0% +1 plus V 2 equal 1 and over here and + + + align:start position:0% +1 plus V 2 equal 1 and over here and +over here and over here so the unit ball + + align:start position:0% +over here and over here so the unit ball + + + align:start position:0% +over here and over here so the unit ball +in the l1 norm is a diamond and that's a + + align:start position:0% +in the l1 norm is a diamond and that's a + + + align:start position:0% +in the l1 norm is a diamond and that's a +very important picture it reflects in a + + align:start position:0% +very important picture it reflects in a + + + align:start position:0% +very important picture it reflects in a +simple very simple way something + + align:start position:0% +simple very simple way something + + + align:start position:0% +simple very simple way something +important about the l1 norm and the + + align:start position:0% +important about the l1 norm and the + + + align:start position:0% +important about the l1 norm and the +reason it's just exploded him in + + align:start position:0% +reason it's just exploded him in + + + align:start position:0% +reason it's just exploded him in +importance let me continue though what + + align:start position:0% +importance let me continue though what + + + align:start position:0% +importance let me continue though what +about the max norm the Max or V infinity + + align:start position:0% +about the max norm the Max or V infinity + + + align:start position:0% +about the max norm the Max or V infinity +what so again let me plot these guys + + align:start position:0% +what so again let me plot these guys + + + align:start position:0% +what so again let me plot these guys +these guys are certainly gonna be in it + + align:start position:0% +these guys are certainly gonna be in it + + + align:start position:0% +these guys are certainly gonna be in it +again they're zero + + align:start position:0% +again they're zero + + + align:start position:0% +again they're zero +you know the plus or minus I and plus or + + align:start position:0% +you know the plus or minus I and plus or + + + align:start position:0% +you know the plus or minus I and plus or +minus J that are good friends what's the + + align:start position:0% +minus J that are good friends what's the + + + align:start position:0% +minus J that are good friends what's the +rest of the boundary look like now now + + align:start position:0% +rest of the boundary look like now now + + + align:start position:0% +rest of the boundary look like now now +this is this means max so what what are + + align:start position:0% +this is this means max so what what are + + + align:start position:0% +this is this means max so what what are +the rest of the points you see it does + + align:start position:0% +the rest of the points you see it does + + + align:start position:0% +the rest of the points you see it does +take a little thought but then you get + + align:start position:0% +take a little thought but then you get + + + align:start position:0% +take a little thought but then you get +it and you don't for forget it ok so + + align:start position:0% +it and you don't for forget it ok so + + + align:start position:0% +it and you don't for forget it ok so +what's what's up I'm looking so suppose + + align:start position:0% +what's what's up I'm looking so suppose + + + align:start position:0% +what's what's up I'm looking so suppose +the maximum is V one + + align:start position:0% +the maximum is V one + + + align:start position:0% +the maximum is V one +I think you're gonna go I I think it's + + align:start position:0% +I think you're gonna go I I think it's + + + align:start position:0% +I think you're gonna go I I think it's +gonna look like that out - out - one + + align:start position:0% +gonna look like that out - out - one + + + align:start position:0% +gonna look like that out - out - one +zero and up to zero one and up here the + + align:start position:0% +zero and up to zero one and up here the + + + align:start position:0% +zero and up to zero one and up here the +vector would be one one point for + + align:start position:0% +vector would be one one point for + + + align:start position:0% +vector would be one one point for +something so the maximum would be one is + + align:start position:0% +something so the maximum would be one is + + + align:start position:0% +something so the maximum would be one is +that okay so so so somehow what really + + align:start position:0% +that okay so so so somehow what really + + + align:start position:0% +that okay so so so somehow what really +sees as you change this number P you + + align:start position:0% +sees as you change this number P you + + + align:start position:0% +sees as you change this number P you +start with people one or daimond and it + + align:start position:0% +start with people one or daimond and it + + + align:start position:0% +start with people one or daimond and it +kind of swells out to be a circle at P + + align:start position:0% +kind of swells out to be a circle at P + + + align:start position:0% +kind of swells out to be a circle at P +equal to 2 and then it kind of keeps + + align:start position:0% +equal to 2 and then it kind of keeps + + + align:start position:0% +equal to 2 and then it kind of keeps +swelling to be a square at P equal + + align:start position:0% +swelling to be a square at P equal + + + align:start position:0% +swelling to be a square at P equal +infinity that's a that's a interesting + + align:start position:0% +infinity that's a that's a interesting + + + align:start position:0% +infinity that's a that's a interesting +thing and yeah now what's the problem + + align:start position:0% +thing and yeah now what's the problem + + + align:start position:0% +thing and yeah now what's the problem +with the 0 norm where are the points + + align:start position:0% +with the 0 norm where are the points + + + align:start position:0% +with the 0 norm where are the points +with one non zero so so so I'm plotting + + align:start position:0% +with one non zero so so so I'm plotting + + + align:start position:0% +with one non zero so so so I'm plotting +ball where are the where the where are + + align:start position:0% +ball where are the where the where are + + + align:start position:0% +ball where are the where the where are +the vectors in this thing that have one + + align:start position:0% +the vectors in this thing that have one + + + align:start position:0% +the vectors in this thing that have one +non-zero not not zero nonzero so that + + align:start position:0% +non-zero not not zero nonzero so that + + + align:start position:0% +non-zero not not zero nonzero so that +that's not included and but I but so + + align:start position:0% +that's not included and but I but so + + + align:start position:0% +that's not included and but I but so +what do I have + + align:start position:0% +what do I have + + + align:start position:0% +what do I have +I'm not allowed the vector one-third + + align:start position:0% +I'm not allowed the vector one-third + + + align:start position:0% +I'm not allowed the vector one-third +two-thirds because that has two non + + align:start position:0% +two-thirds because that has two non + + + align:start position:0% +two-thirds because that has two non +zeros so where are the points with only + + align:start position:0% +zeros so where are the points with only + + + align:start position:0% +zeros so where are the points with only +one nonzero yeah on the axes yeah that + + align:start position:0% +one nonzero yeah on the axes yeah that + + + align:start position:0% +one nonzero yeah on the axes yeah that +does tell you so he can be there and + + align:start position:0% +does tell you so he can be there and + + + align:start position:0% +does tell you so he can be there and +there okay without guy and of course so + + align:start position:0% +there okay without guy and of course so + + + align:start position:0% +there okay without guy and of course so +is just keep going out so it totally + + align:start position:0% +is just keep going out so it totally + + + align:start position:0% +is just keep going out so it totally +violates the you know so maybe the point + + align:start position:0% +violates the you know so maybe the point + + + align:start position:0% +violates the you know so maybe the point +that I should make about these figures + + align:start position:0% +that I should make about these figures + + + align:start position:0% +that I should make about these figures +so so like what's happening when I go + + align:start position:0% +so so like what's happening when I go + + + align:start position:0% +so so like what's happening when I go +down to zero I'm served it really that + + align:start position:0% +down to zero I'm served it really that + + + align:start position:0% +down to zero I'm served it really that +finger should be on the other end right + + align:start position:0% +finger should be on the other end right + + + align:start position:0% +finger should be on the other end right +oh no shoot this guy's in the middle + + align:start position:0% +oh no shoot this guy's in the middle + + + align:start position:0% +oh no shoot this guy's in the middle +this is a badly drawn finger l2 is kind + + align:start position:0% +this is a badly drawn finger l2 is kind + + + align:start position:0% +this is a badly drawn finger l2 is kind +of a center guy l1 is the at one end el + + align:start position:0% +of a center guy l1 is the at one end el + + + align:start position:0% +of a center guy l1 is the at one end el +infinities at the other end and this one + + align:start position:0% +infinities at the other end and this one + + + align:start position:0% +infinities at the other end and this one +has gone off and the left there the the + + align:start position:0% +has gone off and the left there the the + + + align:start position:0% +has gone off and the left there the the +diamond has yeah what's happened here as + + align:start position:0% +diamond has yeah what's happened here as + + + align:start position:0% +diamond has yeah what's happened here as +that one goes down towards zero none of + + align:start position:0% +that one goes down towards zero none of + + + align:start position:0% +that one goes down towards zero none of +these will be okay these these these + + align:start position:0% +these will be okay these these these + + + align:start position:0% +these will be okay these these these +balls will or these sets will lose + + align:start position:0% +balls will or these sets will lose + + + align:start position:0% +balls will or these sets will lose +weight yeah so they'll always have these + + align:start position:0% +weight yeah so they'll always have these + + + align:start position:0% +weight yeah so they'll always have these +points in but they'll be like this and + + align:start position:0% +points in but they'll be like this and + + + align:start position:0% +points in but they'll be like this and +then like this and then finally in the + + align:start position:0% +then like this and then finally in the + + + align:start position:0% +then like this and then finally in the +in the unacceptable limit but none of + + align:start position:0% +in the unacceptable limit but none of + + + align:start position:0% +in the unacceptable limit but none of +those this was not any good either this + + align:start position:0% +those this was not any good either this + + + align:start position:0% +those this was not any good either this +this was for P equal half let's say sort + + align:start position:0% +this was for P equal half let's say sort + + + align:start position:0% +this was for P equal half let's say sort +of uh that's a P equal to happen that's + + align:start position:0% +of uh that's a P equal to happen that's + + + align:start position:0% +of uh that's a P equal to happen that's +not a good norm yeah so maybe the thing + + align:start position:0% +not a good norm yeah so maybe the thing + + + align:start position:0% +not a good norm yeah so maybe the thing +you so there's a property of the circle + + align:start position:0% +you so there's a property of the circle + + + align:start position:0% +you so there's a property of the circle +the diamond and the square which is a + + align:start position:0% +the diamond and the square which is a + + + align:start position:0% +the diamond and the square which is a +nice math property of those of those + + align:start position:0% +nice math property of those of those + + + align:start position:0% +nice math property of those of those +three sets and is not possessed by this + + align:start position:0% +three sets and is not possessed by this + + + align:start position:0% +three sets and is not possessed by this +as this thing loses weight I lose the + + align:start position:0% +as this thing loses weight I lose the + + + align:start position:0% +as this thing loses weight I lose the +property and then of course that's + + align:start position:0% +property and then of course that's + + + align:start position:0% +property and then of course that's +totally lost over there do you know what + + align:start position:0% +totally lost over there do you know what + + + align:start position:0% +totally lost over there do you know what +that property would be what what it's + + align:start position:0% +that property would be what what it's + + + align:start position:0% +that property would be what what it's +for you concave convex convex I would + + align:start position:0% +for you concave convex convex I would + + + align:start position:0% +for you concave convex convex I would +say convex this is true norm has convex + + align:start position:0% +say convex this is true norm has convex + + + align:start position:0% +say convex this is true norm has convex +uni-ball maybe maybe for ball I'm taking + + align:start position:0% +uni-ball maybe maybe for ball I'm taking + + + align:start position:0% +uni-ball maybe maybe for ball I'm taking +all of these yeah so I'm allowing the + + align:start position:0% +all of these yeah so I'm allowing the + + + align:start position:0% +all of these yeah so I'm allowing the +insides of these shapes so this is not a + + align:start position:0% +insides of these shapes so this is not a + + + align:start position:0% +insides of these shapes so this is not a +convex set that set which I shouldn't + + align:start position:0% +convex set that set which I shouldn't + + + align:start position:0% +convex set that set which I shouldn't +so not not convex would be this one with + + align:start position:0% + + + + align:start position:0% + +and that reflects the fact that the oh + + align:start position:0% +and that reflects the fact that the oh + + + align:start position:0% +and that reflects the fact that the oh +the rules for a norm are broken the + + align:start position:0% +the rules for a norm are broken the + + + align:start position:0% +the rules for a norm are broken the +triangle inequality is probably broken + + align:start position:0% +triangle inequality is probably broken + + + align:start position:0% +triangle inequality is probably broken +and that yep I think that's sort of like + + align:start position:0% +and that yep I think that's sort of like + + + align:start position:0% +and that yep I think that's sort of like +worth remembering and then one more norm + + align:start position:0% +worth remembering and then one more norm + + + align:start position:0% +worth remembering and then one more norm +that's natural to think about is so s as + + align:start position:0% +that's natural to think about is so s as + + + align:start position:0% +that's natural to think about is so s as +in the Piazza question s does always + + align:start position:0% +in the Piazza question s does always + + + align:start position:0% +in the Piazza question s does always +represent a symmetric matrix in 1806 + + align:start position:0% +represent a symmetric matrix in 1806 + + + align:start position:0% +represent a symmetric matrix in 1806 +five and now I'm gonna ask my norm is + + align:start position:0% +five and now I'm gonna ask my norm is + + + align:start position:0% +five and now I'm gonna ask my norm is +going to be so I'm gonna call it the s + + align:start position:0% +going to be so I'm gonna call it the s + + + align:start position:0% +going to be so I'm gonna call it the s +norm so asses up actually it's a + + align:start position:0% +norm so asses up actually it's a + + + align:start position:0% +norm so asses up actually it's a +positive definite symmetric matrix F is + + align:start position:0% +positive definite symmetric matrix F is + + + align:start position:0% +positive definite symmetric matrix F is +a positive definite symmetric matrix and + + align:start position:0% +a positive definite symmetric matrix and + + + align:start position:0% +a positive definite symmetric matrix and +what do I do + + align:start position:0% +what do I do + + + align:start position:0% +what do I do +I'll take V transpose AV s V sorry okay + + align:start position:0% +I'll take V transpose AV s V sorry okay + + + align:start position:0% +I'll take V transpose AV s V sorry okay +what's our word for that the energy + + align:start position:0% +what's our word for that the energy + + + align:start position:0% +what's our word for that the energy +that's the energy in the vector V and + + align:start position:0% +that's the energy in the vector V and + + + align:start position:0% +that's the energy in the vector V and +I'll take the square root so that I so + + align:start position:0% +I'll take the square root so that I so + + + align:start position:0% +I'll take the square root so that I so +that I now have the lengths of two if I + + align:start position:0% +that I now have the lengths of two if I + + + align:start position:0% +that I now have the lengths of two if I +double V from V 2 to V then I get a 2 + + align:start position:0% +double V from V 2 to V then I get a 2 + + + align:start position:0% +double V from V 2 to V then I get a 2 +here and a 2 here and when I take this + + align:start position:0% +here and a 2 here and when I take this + + + align:start position:0% +here and a 2 here and when I take this +square root I get a overall two and + + align:start position:0% +square root I get a overall two and + + + align:start position:0% +square root I get a overall two and +that's what I want I want the norm to + + align:start position:0% +that's what I want I want the norm to + + + align:start position:0% +that's what I want I want the norm to +grow linearly with the two or three or + + align:start position:0% +grow linearly with the two or three or + + + align:start position:0% +grow linearly with the two or three or +whatever I multiply by but what is the + + align:start position:0% +whatever I multiply by but what is the + + + align:start position:0% +whatever I multiply by but what is the +shape of this thing so what is the + + align:start position:0% +shape of this thing so what is the + + + align:start position:0% +shape of this thing so what is the +what is the shape I'm gonna get a + + align:start position:0% +what is the shape I'm gonna get a + + + align:start position:0% +what is the shape I'm gonna get a +picture like that so what is the shape + + align:start position:0% +picture like that so what is the shape + + + align:start position:0% +picture like that so what is the shape +of V transpose s V equal one less or + + align:start position:0% +of V transpose s V equal one less or + + + align:start position:0% +of V transpose s V equal one less or +equal one if s is a positive symmetric + + align:start position:0% +equal one if s is a positive symmetric + + + align:start position:0% +equal one if s is a positive symmetric +positive letters tell us I'm claiming + + align:start position:0% +positive letters tell us I'm claiming + + + align:start position:0% +positive letters tell us I'm claiming +that we get a bunch of norms when do we + + align:start position:0% +that we get a bunch of norms when do we + + + align:start position:0% +that we get a bunch of norms when do we +get the l2 norm what what matrix s would + + align:start position:0% +get the l2 norm what what matrix s would + + + align:start position:0% +get the l2 norm what what matrix s would +this give us the l2 norm the identity + + align:start position:0% +this give us the l2 norm the identity + + + align:start position:0% +this give us the l2 norm the identity +certainly now what's going to happen if + + align:start position:0% +certainly now what's going to happen if + + + align:start position:0% +certainly now what's going to happen if +I use some different matrix s this + + align:start position:0% +I use some different matrix s this + + + align:start position:0% +I use some different matrix s this +circle is going to change shape I'm + + align:start position:0% +circle is going to change shape I'm + + + align:start position:0% +circle is going to change shape I'm +gonna have a different norm depending on + + align:start position:0% +gonna have a different norm depending on + + + align:start position:0% +gonna have a different norm depending on +s and a typical case would be s equal to + + align:start position:0% +s and a typical case would be s equal to + + + align:start position:0% +s and a typical case would be s equal to +3 that's a positive definite symmetric + + align:start position:0% +3 that's a positive definite symmetric + + + align:start position:0% +3 that's a positive definite symmetric +matrix and this this now I would be + + align:start position:0% +matrix and this this now I would be + + + align:start position:0% +matrix and this this now I would be +drawing the graph of 2 V 1 squared plus + + align:start position:0% +drawing the graph of 2 V 1 squared plus + + + align:start position:0% +drawing the graph of 2 V 1 squared plus +3 V 2 squared that would be the energy + + align:start position:0% +3 V 2 squared that would be the energy + + + align:start position:0% +3 V 2 squared that would be the energy +right equal one and I just want you to + + align:start position:0% +right equal one and I just want you to + + + align:start position:0% +right equal one and I just want you to +tell me what shape that is so that's a + + align:start position:0% +tell me what shape that is so that's a + + + align:start position:0% +tell me what shape that is so that's a +perfectly good norm that you could check + + align:start position:0% +perfectly good norm that you could check + + + align:start position:0% +perfectly good norm that you could check +all its properties they all come out + + align:start position:0% +all its properties they all come out + + + align:start position:0% +all its properties they all come out +easily but I get a new picture a new + + align:start position:0% +easily but I get a new picture a new + + + align:start position:0% +easily but I get a new picture a new +norm that's kind of adjustable you could + + align:start position:0% +norm that's kind of adjustable you could + + + align:start position:0% +norm that's kind of adjustable you could +say it's a weighted norm weights mean + + align:start position:0% +say it's a weighted norm weights mean + + + align:start position:0% +say it's a weighted norm weights mean +that you kind of have picked some + + align:start position:0% +that you kind of have picked some + + + align:start position:0% +that you kind of have picked some +numbers sort of appropriate to the + + align:start position:0% +numbers sort of appropriate to the + + + align:start position:0% +numbers sort of appropriate to the +particular problem well suppose those + + align:start position:0% +particular problem well suppose those + + + align:start position:0% +particular problem well suppose those +numbers are 2 and 3 what shape is the + + align:start position:0% +numbers are 2 and 3 what shape is the + + + align:start position:0% +numbers are 2 and 3 what shape is the +unit ball in this s norm it's in ellipse + + align:start position:0% +unit ball in this s norm it's in ellipse + + + align:start position:0% +unit ball in this s norm it's in ellipse +right it's an ellipse and I guess it + + align:start position:0% +right it's an ellipse and I guess it + + + align:start position:0% +right it's an ellipse and I guess it +will actually be so the larger number 3 + + align:start position:0% +will actually be so the larger number 3 + + + align:start position:0% +will actually be so the larger number 3 +well will mean you can't go as far as + + align:start position:0% +well will mean you can't go as far as + + + align:start position:0% +well will mean you can't go as far as +a smaller number - I think it would + + align:start position:0% +a smaller number - I think it would + + + align:start position:0% +a smaller number - I think it would +probably be an ellipse like this and the + + align:start position:0% +probably be an ellipse like this and the + + + align:start position:0% +probably be an ellipse like this and the +axes axis lengths of the ellipse would + + align:start position:0% +axes axis lengths of the ellipse would + + + align:start position:0% +axes axis lengths of the ellipse would +probably have something to do with it - + + align:start position:0% +probably have something to do with it - + + + align:start position:0% +probably have something to do with it - +in the three okay so that's just now you + + align:start position:0% +in the three okay so that's just now you + + + align:start position:0% +in the three okay so that's just now you +know really all the vector norms that + + align:start position:0% +know really all the vector norms that + + + align:start position:0% +know really all the vector norms that +are sort of natural to use these come up + + align:start position:0% +are sort of natural to use these come up + + + align:start position:0% +are sort of natural to use these come up +in a natural way they're all as we said + + align:start position:0% +in a natural way they're all as we said + + + align:start position:0% +in a natural way they're all as we said +the identity matrix brings us back to + + align:start position:0% +the identity matrix brings us back to + + + align:start position:0% +the identity matrix brings us back to +the two norm so these are all sort of + + align:start position:0% +the two norm so these are all sort of + + + align:start position:0% +the two norm so these are all sort of +variations on the two norm + + align:start position:0% +variations on the two norm + + + align:start position:0% +variations on the two norm +these are variations as P runs from 1 up + + align:start position:0% +these are variations as P runs from 1 up + + + align:start position:0% +these are variations as P runs from 1 up +to 2 onto infinity and is not allowed to + + align:start position:0% +to 2 onto infinity and is not allowed to + + + align:start position:0% +to 2 onto infinity and is not allowed to +go below 1 okay that's norms and then + + align:start position:0% +go below 1 okay that's norms and then + + + align:start position:0% +go below 1 okay that's norms and then +maybe you can actually see from this + + align:start position:0% +maybe you can actually see from this + + + align:start position:0% +maybe you can actually see from this +picture here's our like somewhat hokey + + align:start position:0% + + + + align:start position:0% + +idea of why it is that this norm + + align:start position:0% +idea of why it is that this norm + + + align:start position:0% +idea of why it is that this norm +minimizing the so minimizing there or in + + align:start position:0% +minimizing the so minimizing there or in + + + align:start position:0% +minimizing the so minimizing there or in +this norm so what do I mean by that here + + align:start position:0% +this norm so what do I mean by that here + + + align:start position:0% +this norm so what do I mean by that here +would be a typical problem minimize + + align:start position:0% + + + + align:start position:0% + +subject to ax equal B the l1 oh sorry + + align:start position:0% +subject to ax equal B the l1 oh sorry + + + align:start position:0% +subject to ax equal B the l1 oh sorry +I'm using X now yeah one norm of the l1 + + align:start position:0% +I'm using X now yeah one norm of the l1 + + + align:start position:0% +I'm using X now yeah one norm of the l1 +norm of X so that would be an important + + align:start position:0% +norm of X so that would be an important + + + align:start position:0% +norm of X so that would be an important +problem actually it has a name people + + align:start position:0% +problem actually it has a name people + + + align:start position:0% +problem actually it has a name people +have spent a lot of time thinking of a + + align:start position:0% +have spent a lot of time thinking of a + + + align:start position:0% +have spent a lot of time thinking of a +fast way to solve it it's almost like + + align:start position:0% +fast way to solve it it's almost like + + + align:start position:0% +fast way to solve it it's almost like +least squares what would what would make + + align:start position:0% +least squares what would what would make + + + align:start position:0% +least squares what would what would make +it more like these squares would be + + align:start position:0% +it more like these squares would be + + + align:start position:0% +it more like these squares would be +change that to two yeah yeah can I just + + align:start position:0% +change that to two yeah yeah can I just + + + align:start position:0% +change that to two yeah yeah can I just +sort of like sketch without making a big + + align:start position:0% +sort of like sketch without making a big + + + align:start position:0% +sort of like sketch without making a big +argument here the difference between L + + align:start position:0% +argument here the difference between L + + + align:start position:0% +argument here the difference between L +equal 1 or + + align:start position:0% +equal 1 or + + + align:start position:0% +equal 1 or +to here yeah just I'll just draw a + + align:start position:0% +to here yeah just I'll just draw a + + + align:start position:0% +to here yeah just I'll just draw a +picture now erase this ellipse but you + + align:start position:0% +picture now erase this ellipse but you + + + align:start position:0% +picture now erase this ellipse but you +won't forget okay so this this is our + + align:start position:0% +won't forget okay so this this is our + + + align:start position:0% +won't forget okay so this this is our +problem l with l1 it has a famous name + + align:start position:0% +problem l with l1 it has a famous name + + + align:start position:0% +problem l with l1 it has a famous name +basis pursuit + + align:start position:0% +basis pursuit + + + align:start position:0% +basis pursuit +well famous to people who work in + + align:start position:0% +well famous to people who work in + + + align:start position:0% +well famous to people who work in +optimization for l2 it has an important + + align:start position:0% +optimization for l2 it has an important + + + align:start position:0% +optimization for l2 it has an important +name well it's sort of like these + + align:start position:0% +name well it's sort of like these + + + align:start position:0% +name well it's sort of like these +squares Ridge regression all sorts of + + align:start position:0% +squares Ridge regression all sorts of + + + align:start position:0% +squares Ridge regression all sorts of +the this is like a beautiful model + + align:start position:0% +the this is like a beautiful model + + + align:start position:0% +the this is like a beautiful model +problem among all solutions to ax + + align:start position:0% +problem among all solutions to ax + + + align:start position:0% +problem among all solutions to ax +suppose this is just one equation like + + align:start position:0% +suppose this is just one equation like + + + align:start position:0% +suppose this is just one equation like +c1 x1 plus c2 x2 equals some right side + + align:start position:0% +c1 x1 plus c2 x2 equals some right side + + + align:start position:0% +c1 x1 plus c2 x2 equals some right side +B so the X's the constraint says that + + align:start position:0% +B so the X's the constraint says that + + + align:start position:0% +B so the X's the constraint says that +the vectors X have to be on a line + + align:start position:0% +the vectors X have to be on a line + + + align:start position:0% +the vectors X have to be on a line +there's suppose that's a graph of that + + align:start position:0% +there's suppose that's a graph of that + + + align:start position:0% +there's suppose that's a graph of that +line so as among all these X's which one + + align:start position:0% +line so as among all these X's which one + + + align:start position:0% +line so as among all these X's which one +yeah I never realizing what is what I'm + + align:start position:0% +yeah I never realizing what is what I'm + + + align:start position:0% +yeah I never realizing what is what I'm +gonna say is gonna be smart okay I mean + + align:start position:0% +gonna say is gonna be smart okay I mean + + + align:start position:0% +gonna say is gonna be smart okay I mean +not it's gonna be nice not gonna be + + align:start position:0% +not it's gonna be nice not gonna be + + + align:start position:0% +not it's gonna be nice not gonna be +difficult + + align:start position:0% +difficult + + + align:start position:0% +difficult +let's do the one we know best l2 so + + align:start position:0% +let's do the one we know best l2 so + + + align:start position:0% +let's do the one we know best l2 so +here's a picture of the line let me let + + align:start position:0% +here's a picture of the line let me let + + + align:start position:0% +here's a picture of the line let me let +me make it a little more tilted so so + + align:start position:0% +me make it a little more tilted so so + + + align:start position:0% +me make it a little more tilted so so +you yeah yeah yeah like like two three + + align:start position:0% +you yeah yeah yeah like like two three + + + align:start position:0% +you yeah yeah yeah like like two three +okay where this is the XY plane here's X + + align:start position:0% +okay where this is the XY plane here's X + + + align:start position:0% +okay where this is the XY plane here's X +1 there's X 2 here are the pair of the + + align:start position:0% +1 there's X 2 here are the pair of the + + + align:start position:0% +1 there's X 2 here are the pair of the +points that satisfy my condition which + + align:start position:0% +points that satisfy my condition which + + + align:start position:0% +points that satisfy my condition which +one minimizes which point on that line + + align:start position:0% +one minimizes which point on that line + + + align:start position:0% +one minimizes which point on that line +minimizes has the smallest l2 norm which + + align:start position:0% +minimizes has the smallest l2 norm which + + + align:start position:0% +minimizes has the smallest l2 norm which +point on the line has the smallest l2 + + align:start position:0% +point on the line has the smallest l2 + + + align:start position:0% +point on the line has the smallest l2 +norm yeah you're drawing the right + + align:start position:0% +norm yeah you're drawing the right + + + align:start position:0% +norm yeah you're drawing the right +figure with your hands the smallest l2 + + align:start position:0% +figure with your hands the smallest l2 + + + align:start position:0% +figure with your hands the smallest l2 +norm L to remember is just how far out + + align:start position:0% +norm L to remember is just how far out + + + align:start position:0% +norm L to remember is just how far out +you go + + align:start position:0% +you go + + + align:start position:0% +you go +it's it's + + align:start position:0% +it's it's + + + align:start position:0% +it's it's +circular here so it doesn't matter what + + align:start position:0% +circular here so it doesn't matter what + + + align:start position:0% +circular here so it doesn't matter what +direction they all giving the same l + + align:start position:0% +direction they all giving the same l + + + align:start position:0% +direction they all giving the same l +2-norm it's just how far so we're + + align:start position:0% +2-norm it's just how far so we're + + + align:start position:0% +2-norm it's just how far so we're +looking for the closest point on the + + align:start position:0% +looking for the closest point on the + + + align:start position:0% +looking for the closest point on the +line because we don't want to go any + + align:start position:0% +line because we don't want to go any + + + align:start position:0% +line because we don't want to go any +further we want to go a minimum distance + + align:start position:0% +further we want to go a minimum distance + + + align:start position:0% +further we want to go a minimum distance +with two now so if so where's the point + + align:start position:0% +with two now so if so where's the point + + + align:start position:0% +with two now so if so where's the point +at minimum distance yeah it's just show + + align:start position:0% +at minimum distance yeah it's just show + + + align:start position:0% +at minimum distance yeah it's just show +me again once more with hands or + + align:start position:0% +me again once more with hands or + + + align:start position:0% +me again once more with hands or +whatever it'll be that I didn't want + + align:start position:0% +whatever it'll be that I didn't want + + + align:start position:0% +whatever it'll be that I didn't want +45-degree angles there I'm gonna erase + + align:start position:0% +45-degree angles there I'm gonna erase + + + align:start position:0% +45-degree angles there I'm gonna erase +it again and really this time I'm gonna + + align:start position:0% +it again and really this time I'm gonna + + + align:start position:0% +it again and really this time I'm gonna +get angles that are not 45 all right + + align:start position:0% +get angles that are not 45 all right + + + align:start position:0% +get angles that are not 45 all right +brilliant got it okay that's my line + + align:start position:0% +brilliant got it okay that's my line + + + align:start position:0% +brilliant got it okay that's my line +okay and what's the nearest point in the + + align:start position:0% +okay and what's the nearest point in the + + + align:start position:0% +okay and what's the nearest point in the +l2 norm + + align:start position:0% +l2 norm + + + align:start position:0% +l2 norm +here's the winner in l2 right the + + align:start position:0% +here's the winner in l2 right the + + + align:start position:0% +here's the winner in l2 right the +nearest point everybody sees that + + align:start position:0% +nearest point everybody sees that + + + align:start position:0% +nearest point everybody sees that +picture so that's the that's you know + + align:start position:0% +picture so that's the that's you know + + + align:start position:0% +picture so that's the that's you know +that's a basic picture for for + + align:start position:0% +that's a basic picture for for + + + align:start position:0% +that's a basic picture for for +minimizing something with a constraint + + align:start position:0% +minimizing something with a constraint + + + align:start position:0% +minimizing something with a constraint +which is the fundamental problem of + + align:start position:0% +which is the fundamental problem of + + + align:start position:0% +which is the fundamental problem of +optimization of neural nets of + + align:start position:0% +optimization of neural nets of + + + align:start position:0% +optimization of neural nets of +everything really of life well I'm + + align:start position:0% +everything really of life well I'm + + + align:start position:0% +everything really of life well I'm +philosophical so okay that's that's but + + align:start position:0% +philosophical so okay that's that's but + + + align:start position:0% +philosophical so okay that's that's but +of course it always mean the question + + align:start position:0% +of course it always mean the question + + + align:start position:0% +of course it always mean the question +always is and maybe it's true in life to + + align:start position:0% +always is and maybe it's true in life to + + + align:start position:0% +always is and maybe it's true in life to +which norm are you using okay now count + + align:start position:0% +which norm are you using okay now count + + + align:start position:0% +which norm are you using okay now count +and show with yourself that was the + + align:start position:0% +and show with yourself that was the + + + align:start position:0% +and show with yourself that was the +minimum in l2 that's the shortest + + align:start position:0% +minimum in l2 that's the shortest + + + align:start position:0% +minimum in l2 that's the shortest +distance where a distance means what we + + align:start position:0% +distance where a distance means what we + + + align:start position:0% +distance where a distance means what we +usually think of it as meaning but now + + align:start position:0% +usually think of it as meaning but now + + + align:start position:0% +usually think of it as meaning but now +let's go for the l1 norm which point on + + align:start position:0% +let's go for the l1 norm which point on + + + align:start position:0% +let's go for the l1 norm which point on +the line has the smallest l1 norm so now + + align:start position:0% +the line has the smallest l1 norm so now + + + align:start position:0% +the line has the smallest l1 norm so now +I'm going to add the two so if this is + + align:start position:0% +I'm going to add the two so if this is + + + align:start position:0% +I'm going to add the two so if this is +some point a this is some point a zero + + align:start position:0% +some point a this is some point a zero + + + align:start position:0% +some point a this is some point a zero +and this is some point zero B right + + align:start position:0% +and this is some point zero B right + + + align:start position:0% +and this is some point zero B right +there + + align:start position:0% +there + + + align:start position:0% +there +so those two points are obviously + + align:start position:0% +so those two points are obviously + + + align:start position:0% +so those two points are obviously +important and that point we could figure + + align:start position:0% +important and that point we could figure + + + align:start position:0% +important and that point we could figure +out the formula for + + align:start position:0% +out the formula for + + + align:start position:0% +out the formula for +because it's we we know what the + + align:start position:0% +because it's we we know what the + + + align:start position:0% +because it's we we know what the +geometry is but I've just put those two + + align:start position:0% +geometry is but I've just put those two + + + align:start position:0% +geometry is but I've just put those two +points in so did I get a zero B yeah + + align:start position:0% +points in so did I get a zero B yeah + + + align:start position:0% +points in so did I get a zero B yeah +that's a zero well so let me just ask + + align:start position:0% +that's a zero well so let me just ask + + + align:start position:0% +that's a zero well so let me just ask +you that question + + align:start position:0% +you that question + + + align:start position:0% +you that question +what point on that line has the smallest + + align:start position:0% +what point on that line has the smallest + + + align:start position:0% +what point on that line has the smallest +l1 norm which has the smallest l1 norm + + align:start position:0% + + + + align:start position:0% + +somebody said it just say it a little + + align:start position:0% +somebody said it just say it a little + + + align:start position:0% +somebody said it just say it a little +louder so that you're wrong + + align:start position:0% +louder so that you're wrong + + + align:start position:0% +louder so that you're wrong +tape forever zero B this point that's + + align:start position:0% +tape forever zero B this point that's + + + align:start position:0% +tape forever zero B this point that's +the winner + + align:start position:0% +the winner + + + align:start position:0% +the winner +this is the l1 winner and this was the + + align:start position:0% +this is the l1 winner and this was the + + + align:start position:0% +this is the l1 winner and this was the +l2 the winner and notice what I said + + align:start position:0% +l2 the winner and notice what I said + + + align:start position:0% +l2 the winner and notice what I said +earlier and I didn't see it coming but + + align:start position:0% +earlier and I didn't see it coming but + + + align:start position:0% +earlier and I didn't see it coming but +now I realize this is a finger to put in + + align:start position:0% +now I realize this is a finger to put in + + + align:start position:0% +now I realize this is a finger to put in +the notes the winner has the most zeroes + + align:start position:0% +the notes the winner has the most zeroes + + + align:start position:0% +the notes the winner has the most zeroes +it's the sparse vector it's got a zero + + align:start position:0% +it's the sparse vector it's got a zero + + + align:start position:0% +it's the sparse vector it's got a zero +well out of two components it didn't + + align:start position:0% +well out of two components it didn't + + + align:start position:0% +well out of two components it didn't +have much freedom but it has a zero + + align:start position:0% +have much freedom but it has a zero + + + align:start position:0% +have much freedom but it has a zero +component + + align:start position:0% +component + + + align:start position:0% +component +it sits on the on the on the axes it's + + align:start position:0% +it sits on the on the on the axes it's + + + align:start position:0% +it sits on the on the on the axes it's +the things on the axes that have the + + align:start position:0% +the things on the axes that have the + + + align:start position:0% +the things on the axes that have the +smallest number of components so so yes + + align:start position:0% +smallest number of components so so yes + + + align:start position:0% +smallest number of components so so yes +so this is the picture in l2 in in two + + align:start position:0% +so this is the picture in l2 in in two + + + align:start position:0% +so this is the picture in l2 in in two +sorry the picture in two dimensions so + + align:start position:0% +sorry the picture in two dimensions so + + + align:start position:0% +sorry the picture in two dimensions so +I'm in 2d and you can see that the + + align:start position:0% +I'm in 2d and you can see that the + + + align:start position:0% +I'm in 2d and you can see that the +winner is has a zero component yeah yeah + + align:start position:0% +winner is has a zero component yeah yeah + + + align:start position:0% +winner is has a zero component yeah yeah +and and that's a fact that extends into + + align:start position:0% +and and that's a fact that extends into + + + align:start position:0% +and and that's a fact that extends into +higher dimensions too and that makes the + + align:start position:0% +higher dimensions too and that makes the + + + align:start position:0% +higher dimensions too and that makes the +l1 norm special as I've said yeah is + + align:start position:0% +l1 norm special as I've said yeah is + + + align:start position:0% +l1 norm special as I've said yeah is +there more to say about that example + + align:start position:0% +there more to say about that example + + + align:start position:0% +there more to say about that example +that's for a simple 2d question that + + align:start position:0% +that's for a simple 2d question that + + + align:start position:0% +that's for a simple 2d question that +really makes the point that the l1 + + align:start position:0% +really makes the point that the l1 + + + align:start position:0% +really makes the point that the l1 +winner is there it's not further you + + align:start position:0% +winner is there it's not further you + + + align:start position:0% +winner is there it's not further you +don't go further up the line right + + align:start position:0% +don't go further up the line right + + + align:start position:0% +don't go further up the line right +because because then you're then you + + align:start position:0% +because because then you're then you + + + align:start position:0% +because because then you're then you +have even that's bad in all ways when + + align:start position:0% +have even that's bad in all ways when + + + align:start position:0% +have even that's bad in all ways when +you go up further you're you're adding + + align:start position:0% +you go up further you're you're adding + + + align:start position:0% +you go up further you're you're adding +some nonzero + + align:start position:0% +some nonzero + + + align:start position:0% +some nonzero +first component and you're increasing + + align:start position:0% +first component and you're increasing + + + align:start position:0% +first component and you're increasing +the non zero over second component so + + align:start position:0% +the non zero over second component so + + + align:start position:0% +the non zero over second component so +your that's a bad idea + + align:start position:0% +your that's a bad idea + + + align:start position:0% +your that's a bad idea +that's a bad idea this is this is the + + align:start position:0% +that's a bad idea this is this is the + + + align:start position:0% +that's a bad idea this is this is the +winner and in a way here's the picture + + align:start position:0% +winner and in a way here's the picture + + + align:start position:0% +winner and in a way here's the picture +yeah oh yeah I should prepare these + + align:start position:0% +yeah oh yeah I should prepare these + + + align:start position:0% +yeah oh yeah I should prepare these +lectures but this one's coming out all + + align:start position:0% +lectures but this one's coming out all + + + align:start position:0% +lectures but this one's coming out all +right anyway so this so the picture + + align:start position:0% +right anyway so this so the picture + + + align:start position:0% +right anyway so this so the picture +there is the nearest ball it's at that + + align:start position:0% +there is the nearest ball it's at that + + + align:start position:0% +there is the nearest ball it's at that +point and what is it can you see that so + + align:start position:0% +point and what is it can you see that so + + + align:start position:0% +point and what is it can you see that so +that star is outside the circle this is + + align:start position:0% +that star is outside the circle this is + + + align:start position:0% +that star is outside the circle this is +the l1 winner so and that's the nearest + + align:start position:0% +the l1 winner so and that's the nearest + + + align:start position:0% +the l1 winner so and that's the nearest +that's the that's is the blow-up of the + + align:start position:0% +that's the that's is the blow-up of the + + + align:start position:0% +that's the that's is the blow-up of the +l1 norm until it hits that's the point + + align:start position:0% +l1 norm until it hits that's the point + + + align:start position:0% +l1 norm until it hits that's the point +where the l1 norm hit do you see it just + + align:start position:0% +where the l1 norm hit do you see it just + + + align:start position:0% +where the l1 norm hit do you see it just +give it a little thought that that + + align:start position:0% +give it a little thought that that + + + align:start position:0% +give it a little thought that that +another another geometric way to see the + + align:start position:0% +another another geometric way to see the + + + align:start position:0% +another another geometric way to see the +answer to this problem is you started + + align:start position:0% +answer to this problem is you started + + + align:start position:0% +answer to this problem is you started +the origin then you blow up a norm until + + align:start position:0% +the origin then you blow up a norm until + + + align:start position:0% +the origin then you blow up a norm until +you get a point on the line that + + align:start position:0% +you get a point on the line that + + + align:start position:0% +you get a point on the line that +satisfies your constraint and because + + align:start position:0% +satisfies your constraint and because + + + align:start position:0% +satisfies your constraint and because +you were blowing up a norm when it hits + + align:start position:0% +you were blowing up a norm when it hits + + + align:start position:0% +you were blowing up a norm when it hits +first that's the smallest blow-up + + align:start position:0% +first that's the smallest blow-up + + + align:start position:0% +first that's the smallest blow-up +possible + + align:start position:0% +possible + + + align:start position:0% +possible +that's the mint that's the guy that + + align:start position:0% +that's the mint that's the guy that + + + align:start position:0% +that's the mint that's the guy that +minimizes ya just think about that + + align:start position:0% +minimizes ya just think about that + + + align:start position:0% +minimizes ya just think about that +picture and I'll draw it better + + align:start position:0% +picture and I'll draw it better + + + align:start position:0% +picture and I'll draw it better +somewhere - well that's vector norms and + + align:start position:0% +somewhere - well that's vector norms and + + + align:start position:0% +somewhere - well that's vector norms and +then I introduced some matrix norms and + + align:start position:0% +then I introduced some matrix norms and + + + align:start position:0% +then I introduced some matrix norms and +let me just say a word about those + + align:start position:0% + + + + align:start position:0% + +okay word about matrix norm so so the + + align:start position:0% +okay word about matrix norm so so the + + + align:start position:0% +okay word about matrix norm so so the +matrix norms were the so so now I have a + + align:start position:0% +matrix norms were the so so now I have a + + + align:start position:0% +matrix norms were the so so now I have a +matrix a and I want to define those same + + align:start position:0% +matrix a and I want to define those same + + + align:start position:0% +matrix a and I want to define those same +three norms again for a matrix and this + + align:start position:0% +three norms again for a matrix and this + + + align:start position:0% +three norms again for a matrix and this +was two norm and what was the two norm + + align:start position:0% +was two norm and what was the two norm + + + align:start position:0% +was two norm and what was the two norm +of a matrix well it was Sigma one turned + + align:start position:0% +of a matrix well it was Sigma one turned + + + align:start position:0% +of a matrix well it was Sigma one turned +out to be so what that doesn't define it + + align:start position:0% +out to be so what that doesn't define it + + + align:start position:0% +out to be so what that doesn't define it +or it could to find it just say okay the + + align:start position:0% +or it could to find it just say okay the + + + align:start position:0% +or it could to find it just say okay the +largest singular value is the two norm + + align:start position:0% +largest singular value is the two norm + + + align:start position:0% +largest singular value is the two norm +of the matrix but actually it comes from + + align:start position:0% +of the matrix but actually it comes from + + + align:start position:0% +of the matrix but actually it comes from +somewhere so I want to speak about this + + align:start position:0% +somewhere so I want to speak about this + + + align:start position:0% +somewhere so I want to speak about this +one first the tomb norm so so so it's + + align:start position:0% +one first the tomb norm so so so it's + + + align:start position:0% +one first the tomb norm so so so it's +the two norm of a matrix and one way to + + align:start position:0% +the two norm of a matrix and one way to + + + align:start position:0% +the two norm of a matrix and one way to +see the two norm of a matrix is to + + align:start position:0% +see the two norm of a matrix is to + + + align:start position:0% +see the two norm of a matrix is to +connected to the 2 norm of vectors I'd + + align:start position:0% +connected to the 2 norm of vectors I'd + + + align:start position:0% +connected to the 2 norm of vectors I'd +like to connect the two norm of matrices + + align:start position:0% +like to connect the two norm of matrices + + + align:start position:0% +like to connect the two norm of matrices +to the two norm of vectors and how shall + + align:start position:0% +to the two norm of vectors and how shall + + + align:start position:0% +to the two norm of vectors and how shall +I do that I think I'm going to look at + + align:start position:0% +I do that I think I'm going to look at + + + align:start position:0% +I do that I think I'm going to look at +the 2 norm of AX over the two norm of X + + align:start position:0% +the 2 norm of AX over the two norm of X + + + align:start position:0% +the 2 norm of AX over the two norm of X +so in a way to me that that ratio is + + align:start position:0% +so in a way to me that that ratio is + + + align:start position:0% +so in a way to me that that ratio is +like the blow up factor if a was 7 times + + align:start position:0% +like the blow up factor if a was 7 times + + + align:start position:0% +like the blow up factor if a was 7 times +the identity to take an easy case if a + + align:start position:0% +the identity to take an easy case if a + + + align:start position:0% +the identity to take an easy case if a +is 7 times the identity what would that + + align:start position:0% +is 7 times the identity what would that + + + align:start position:0% +is 7 times the identity what would that +ratio be yeah 7 if a is if a is 7 I this + + align:start position:0% +ratio be yeah 7 if a is if a is 7 I this + + + align:start position:0% +ratio be yeah 7 if a is if a is 7 I this +this will be 7 X and this will be X and + + align:start position:0% +this will be 7 X and this will be X and + + + align:start position:0% +this will be 7 X and this will be X and +norms the factor 7 comes out so that + + align:start position:0% +norms the factor 7 comes out so that + + + align:start position:0% +norms the factor 7 comes out so that +ratio will be 7 okay + + align:start position:0% +ratio will be 7 okay + + + align:start position:0% +ratio will be 7 okay +for me the norm is take that's the + + align:start position:0% +for me the norm is take that's the + + + align:start position:0% +for me the norm is take that's the +blow-up factor when so here here's my + + align:start position:0% +blow-up factor when so here here's my + + + align:start position:0% +blow-up factor when so here here's my +here's the idea of a matrix norm now I'm + + align:start position:0% +here's the idea of a matrix norm now I'm + + + align:start position:0% +here's the idea of a matrix norm now I'm +doing matrix matrix norm from vector + + align:start position:0% +doing matrix matrix norm from vector + + + align:start position:0% +doing matrix matrix norm from vector +norm and the answer will be maximum the + + align:start position:0% +norm and the answer will be maximum the + + + align:start position:0% +norm and the answer will be maximum the +maximum of this ratio I call that ratio + + align:start position:0% +maximum of this ratio I call that ratio + + + align:start position:0% +maximum of this ratio I call that ratio +of the blow up vector that's just a + + align:start position:0% +of the blow up vector that's just a + + + align:start position:0% +of the blow up vector that's just a +made-up name the maximum over all X's + + align:start position:0% +made-up name the maximum over all X's + + + align:start position:0% +made-up name the maximum over all X's +all the I look to see which vector gets + + align:start position:0% +all the I look to see which vector gets + + + align:start position:0% +all the I look to see which vector gets +blown up the most and that is the norm + + align:start position:0% +blown up the most and that is the norm + + + align:start position:0% +blown up the most and that is the norm +of the matrix + + align:start position:0% +of the matrix + + + align:start position:0% +of the matrix +I know I've I've settled on norms of + + align:start position:0% +I know I've I've settled on norms of + + + align:start position:0% +I know I've I've settled on norms of +vectors that's that's done upstairs + + align:start position:0% +vectors that's that's done upstairs + + + align:start position:0% +vectors that's that's done upstairs +there now I'm looking at norms of + + align:start position:0% +there now I'm looking at norms of + + + align:start position:0% +there now I'm looking at norms of +matrices and this is one way to get a + + align:start position:0% +matrices and this is one way to get a + + + align:start position:0% +matrices and this is one way to get a +good norm of a matrix that kind of comes + + align:start position:0% +good norm of a matrix that kind of comes + + + align:start position:0% +good norm of a matrix that kind of comes +from the two norm so there would be + + align:start position:0% +from the two norm so there would be + + + align:start position:0% +from the two norm so there would be +other norms for matrices coming from + + align:start position:0% +other norms for matrices coming from + + + align:start position:0% +other norms for matrices coming from +other vector norms and those we haven't + + align:start position:0% +other vector norms and those we haven't + + + align:start position:0% +other vector norms and those we haven't +seen but the two norm is this is a very + + align:start position:0% +seen but the two norm is this is a very + + + align:start position:0% +seen but the two norm is this is a very +important one so what is the maximum + + align:start position:0% +important one so what is the maximum + + + align:start position:0% +important one so what is the maximum +value of this of that ratio for a matrix + + align:start position:0% +value of this of that ratio for a matrix + + + align:start position:0% +value of this of that ratio for a matrix +a the claim is that it's Sigma 1 what a + + align:start position:0% +a the claim is that it's Sigma 1 what a + + + align:start position:0% +a the claim is that it's Sigma 1 what a +big equality there now can we see why is + + align:start position:0% +big equality there now can we see why is + + + align:start position:0% +big equality there now can we see why is +why is Sigma 1 the answer to this + + align:start position:0% +why is Sigma 1 the answer to this + + + align:start position:0% +why is Sigma 1 the answer to this +problem I can see a couple of ways to + + align:start position:0% +problem I can see a couple of ways to + + + align:start position:0% +problem I can see a couple of ways to +think about that but that's a very + + align:start position:0% +think about that but that's a very + + + align:start position:0% +think about that but that's a very +important fact in fact this is a way to + + align:start position:0% + + + + align:start position:0% + +discover what Sigma 1 is without all the + + align:start position:0% +discover what Sigma 1 is without all the + + + align:start position:0% +discover what Sigma 1 is without all the +other Sigma's if I look for the X that + + align:start position:0% +other Sigma's if I look for the X that + + + align:start position:0% +other Sigma's if I look for the X that +has the biggest blow-up factor and by + + align:start position:0% +has the biggest blow-up factor and by + + + align:start position:0% +has the biggest blow-up factor and by +the way which X will it be which X will + + align:start position:0% +the way which X will it be which X will + + + align:start position:0% +the way which X will it be which X will +win the max competition here and be + + align:start position:0% +win the max competition here and be + + + align:start position:0% +win the max competition here and be +Sigma 1 times as long + + align:start position:0% +Sigma 1 times as long + + + align:start position:0% +Sigma 1 times as long +Raja's as the the ratio will be Sigma 1 + + align:start position:0% +Raja's as the the ratio will be Sigma 1 + + + align:start position:0% +Raja's as the the ratio will be Sigma 1 +that'll be Sigma 1 when is this thing + + align:start position:0% +that'll be Sigma 1 when is this thing + + + align:start position:0% +that'll be Sigma 1 when is this thing +Sigma 1 times as large as that for which + + align:start position:0% +Sigma 1 times as large as that for which + + + align:start position:0% +Sigma 1 times as large as that for which +X naught for an eigenvector if X was an + + align:start position:0% +X naught for an eigenvector if X was an + + + align:start position:0% +X naught for an eigenvector if X was an +eigenvector what would that ratio be + + align:start position:0% +eigenvector what would that ratio be + + + align:start position:0% +eigenvector what would that ratio be +lambda but if a is not a symmetric + + align:start position:0% +lambda but if a is not a symmetric + + + align:start position:0% +lambda but if a is not a symmetric +matrix + + align:start position:0% +matrix + + + align:start position:0% +matrix +maybe the eigenvectors don't tell you + + align:start position:0% +maybe the eigenvectors don't tell you + + + align:start position:0% +maybe the eigenvectors don't tell you +the the waiter the exact way to go what + + align:start position:0% +the the waiter the exact way to go what + + + align:start position:0% +the the waiter the exact way to go what +so what vector view would you now guess + + align:start position:0% +so what vector view would you now guess + + + align:start position:0% +so what vector view would you now guess +it's not an eigenvector it is a singular + + align:start position:0% +it's not an eigenvector it is a singular + + + align:start position:0% +it's not an eigenvector it is a singular +vector and which singular vectors are + + align:start position:0% +vector and which singular vectors are + + + align:start position:0% +vector and which singular vectors are +probably going to be you v1 + + align:start position:0% +probably going to be you v1 + + + align:start position:0% +probably going to be you v1 +yeah V one makes sense winner so the + + align:start position:0% +yeah V one makes sense winner so the + + + align:start position:0% +yeah V one makes sense winner so the +winner of this competition is X equal V + + align:start position:0% +winner of this competition is X equal V + + + align:start position:0% +winner of this competition is X equal V +1 the first the first right singular + + align:start position:0% +1 the first the first right singular + + + align:start position:0% +1 the first the first right singular +vector and we better be able to check + + align:start position:0% +vector and we better be able to check + + + align:start position:0% +vector and we better be able to check +that so again this maximization problem + + align:start position:0% +that so again this maximization problem + + + align:start position:0% +that so again this maximization problem +the answer tells you is in terms of the + + align:start position:0% +the answer tells you is in terms of the + + + align:start position:0% +the answer tells you is in terms of the +singular vectors so that's a way to find + + align:start position:0% +singular vectors so that's a way to find + + + align:start position:0% +singular vectors so that's a way to find +this first singular vector without + + align:start position:0% +this first singular vector without + + + align:start position:0% +this first singular vector without +finding them all and let's just plug in + + align:start position:0% +finding them all and let's just plug in + + + align:start position:0% +finding them all and let's just plug in +the first thing of their vector and see + + align:start position:0% +the first thing of their vector and see + + + align:start position:0% +the first thing of their vector and see +that the ratio is see what it see that + + align:start position:0% +that the ratio is see what it see that + + + align:start position:0% +that the ratio is see what it see that +the ratio is Sigma 1 so now let me plug + + align:start position:0% +the ratio is Sigma 1 so now let me plug + + + align:start position:0% +the ratio is Sigma 1 so now let me plug +it in so so what do I have I want a V 1 + + align:start position:0% +it in so so what do I have I want a V 1 + + + align:start position:0% +it in so so what do I have I want a V 1 +over length of V 1 okay and I'm hoping + + align:start position:0% +over length of V 1 okay and I'm hoping + + + align:start position:0% +over length of V 1 okay and I'm hoping +to get that answer well what's the bout + + align:start position:0% +to get that answer well what's the bout + + + align:start position:0% +to get that answer well what's the bout +of the denominator here the length of V + + align:start position:0% +of the denominator here the length of V + + + align:start position:0% +of the denominator here the length of V +1 is what no big deal there that's one + + align:start position:0% +1 is what no big deal there that's one + + + align:start position:0% +1 is what no big deal there that's one +what what's the length of the of the top + + align:start position:0% +what what's the length of the of the top + + + align:start position:0% +what what's the length of the of the top +one so so + + align:start position:0% +one so so + + + align:start position:0% +one so so +is a v1 now what is a v1 if v1 is the + + align:start position:0% +is a v1 now what is a v1 if v1 is the + + + align:start position:0% +is a v1 now what is a v1 if v1 is the +first singular first right singular + + align:start position:0% +first singular first right singular + + + align:start position:0% +first singular first right singular +vector then a v1 is Sigma 1 times u1 + + align:start position:0% +vector then a v1 is Sigma 1 times u1 + + + align:start position:0% +vector then a v1 is Sigma 1 times u1 +remember the singular vector deals were + + align:start position:0% +remember the singular vector deals were + + + align:start position:0% +remember the singular vector deals were +AV equals Sigma u AV k equals sigma k UK + + align:start position:0% +AV equals Sigma u AV k equals sigma k UK + + + align:start position:0% +AV equals Sigma u AV k equals sigma k UK +remember that so they're not + + align:start position:0% +remember that so they're not + + + align:start position:0% +remember that so they're not +eigenvectors their singular vectors so + + align:start position:0% +eigenvectors their singular vectors so + + + align:start position:0% +eigenvectors their singular vectors so +that's that is a v1 is the length of + + align:start position:0% +that's that is a v1 is the length of + + + align:start position:0% +that's that is a v1 is the length of +sigma 1 u 1 and it's divided by 1 and of + + align:start position:0% +sigma 1 u 1 and it's divided by 1 and of + + + align:start position:0% +sigma 1 u 1 and it's divided by 1 and of +course u 1 is also a unit vector so I + + align:start position:0% +course u 1 is also a unit vector so I + + + align:start position:0% +course u 1 is also a unit vector so I +just get signal okay so that's another + + align:start position:0% +just get signal okay so that's another + + + align:start position:0% +just get signal okay so that's another +way to say that you can find Sigma 1 by + + align:start position:0% +way to say that you can find Sigma 1 by + + + align:start position:0% +way to say that you can find Sigma 1 by +solving this maximum problem and you get + + align:start position:0% +solving this maximum problem and you get + + + align:start position:0% +solving this maximum problem and you get +that Sigma 1 ok and I could get other + + align:start position:0% +that Sigma 1 ok and I could get other + + + align:start position:0% +that Sigma 1 ok and I could get other +norms matrix norms by by maximizing that + + align:start position:0% +norms matrix norms by by maximizing that + + + align:start position:0% +norms matrix norms by by maximizing that +blow up factor in that vector norm I + + align:start position:0% +blow up factor in that vector norm I + + + align:start position:0% +blow up factor in that vector norm I +won't do that now just to keep control + + align:start position:0% +won't do that now just to keep control + + + align:start position:0% +won't do that now just to keep control +of what we've got now what were the what + + align:start position:0% +of what we've got now what were the what + + + align:start position:0% +of what we've got now what were the what +was the next matrix norm that came in + + align:start position:0% +was the next matrix norm that came in + + + align:start position:0% +was the next matrix norm that came in +last time very very important one for + + align:start position:0% +last time very very important one for + + + align:start position:0% +last time very very important one for +deep learning and neural nets somehow + + align:start position:0% +deep learning and neural nets somehow + + + align:start position:0% +deep learning and neural nets somehow +it's a little simpler than this guy and + + align:start position:0% +it's a little simpler than this guy and + + + align:start position:0% +it's a little simpler than this guy and +what's the what was that matrix norm + + align:start position:0% +what's the what was that matrix norm + + + align:start position:0% +what's the what was that matrix norm +what letter whose name goes here + + align:start position:0% + + + + align:start position:0% + +Frobenius so capital F for Frobenius and + + align:start position:0% +Frobenius so capital F for Frobenius and + + + align:start position:0% +Frobenius so capital F for Frobenius and +that and what was that that was the + + align:start position:0% +that and what was that that was the + + + align:start position:0% +that and what was that that was the +square root of the sum of the all the + + align:start position:0% +square root of the sum of the all the + + + align:start position:0% +square root of the sum of the all the +add up add all the a IJ squares for all + + align:start position:0% +add up add all the a IJ squares for all + + + align:start position:0% +add up add all the a IJ squares for all +over the matrix and then takes a square + + align:start position:0% +over the matrix and then takes a square + + + align:start position:0% +over the matrix and then takes a square +root and then somebody asked a good + + align:start position:0% +root and then somebody asked a good + + + align:start position:0% +root and then somebody asked a good +question after class on Wednesday what + + align:start position:0% +question after class on Wednesday what + + + align:start position:0% +question after class on Wednesday what +has that got to do with the Sigma's + + align:start position:0% +has that got to do with the Sigma's + + + align:start position:0% +has that got to do with the Sigma's +because I my disappoint was that these + + align:start position:0% +because I my disappoint was that these + + + align:start position:0% +because I my disappoint was that these +dorms are the guys that go with the + + align:start position:0% +dorms are the guys that go with the + + + align:start position:0% +dorms are the guys that go with the +Sigma's that does that have nice + + align:start position:0% +Sigma's that does that have nice + + + align:start position:0% +Sigma's that does that have nice +formulas for the Sigma's and here it is + + align:start position:0% +formulas for the Sigma's and here it is + + + align:start position:0% +formulas for the Sigma's and here it is +it's the square root of the sum of the + + align:start position:0% +it's the square root of the sum of the + + + align:start position:0% +it's the square root of the sum of the +squares of all the signals yes sorry let + + align:start position:0% +squares of all the signals yes sorry let + + + align:start position:0% +squares of all the signals yes sorry let +me write Frobenius again but this + + align:start position:0% +me write Frobenius again but this + + + align:start position:0% +me write Frobenius again but this +notation with an F is now pretty + + align:start position:0% +notation with an F is now pretty + + + align:start position:0% +notation with an F is now pretty +standard and we should be able to see + + align:start position:0% +standard and we should be able to see + + + align:start position:0% +standard and we should be able to see +why that number is the same as that + + align:start position:0% +why that number is the same as that + + + align:start position:0% +why that number is the same as that +number yeah I could I could give you a + + align:start position:0% +number yeah I could I could give you a + + + align:start position:0% +number yeah I could I could give you a +reason or I couldn't put it on the + + align:start position:0% +reason or I couldn't put it on the + + + align:start position:0% +reason or I couldn't put it on the +problem set yeah I think it better on + + align:start position:0% +problem set yeah I think it better on + + + align:start position:0% +problem set yeah I think it better on +the problem set because first of all + + align:start position:0% +the problem set because first of all + + + align:start position:0% +the problem set because first of all +I'll get off the hook right away and + + align:start position:0% +I'll get off the hook right away and + + + align:start position:0% +I'll get off the hook right away and +secondly this connection between in + + align:start position:0% +secondly this connection between in + + + align:start position:0% +secondly this connection between in +Probie Nia so it's like a beautiful fact + + align:start position:0% +Probie Nia so it's like a beautiful fact + + + align:start position:0% +Probie Nia so it's like a beautiful fact +about Frobenius norm that you add up all + + align:start position:0% +about Frobenius norm that you add up all + + + align:start position:0% +about Frobenius norm that you add up all +the Sigma Squared's as M times n of them + + align:start position:0% +the Sigma Squared's as M times n of them + + + align:start position:0% +the Sigma Squared's as M times n of them +because it's a all filled matrix or you + + align:start position:0% +because it's a all filled matrix or you + + + align:start position:0% +because it's a all filled matrix or you +add up so another way to say it is we + + align:start position:0% +add up so another way to say it is we + + + align:start position:0% +add up so another way to say it is we +haven't written down the SVD today's a + + align:start position:0% +haven't written down the SVD today's a + + + align:start position:0% +haven't written down the SVD today's a +whoyou Sigma V transpose and the point + + align:start position:0% +whoyou Sigma V transpose and the point + + + align:start position:0% +whoyou Sigma V transpose and the point +is that for the Frobenius norm actually + + align:start position:0% +is that for the Frobenius norm actually + + + align:start position:0% +is that for the Frobenius norm actually +for all these norms I can change you it + + align:start position:0% +for all these norms I can change you it + + + align:start position:0% +for all these norms I can change you it +doesn't change the norm so I can make + + align:start position:0% +doesn't change the norm so I can make + + + align:start position:0% +doesn't change the norm so I can make +you the identity it's you as we all know + + align:start position:0% +you the identity it's you as we all know + + + align:start position:0% +you the identity it's you as we all know +is an orthogonal matrix and what I'm + + align:start position:0% +is an orthogonal matrix and what I'm + + + align:start position:0% +is an orthogonal matrix and what I'm +saying is orthogonal matrix you doesn't + + align:start position:0% +saying is orthogonal matrix you doesn't + + + align:start position:0% +saying is orthogonal matrix you doesn't +change any of these particular norms so + + align:start position:0% +change any of these particular norms so + + + align:start position:0% +change any of these particular norms so +suppose it was the identity same here + + align:start position:0% +suppose it was the identity same here + + + align:start position:0% +suppose it was the identity same here +that could be the identity without + + align:start position:0% +that could be the identity without + + + align:start position:0% +that could be the identity without +changing the norm so we're down to the + + align:start position:0% +changing the norm so we're down to the + + + align:start position:0% +changing the norm so we're down to the +norm of the the Frobenius so what's the + + align:start position:0% +norm of the the Frobenius so what's the + + + align:start position:0% +norm of the the Frobenius so what's the +Frobenius norm + + align:start position:0% +Frobenius norm + + + align:start position:0% +Frobenius norm +of that guy what's the Probie Gnaeus + + align:start position:0% +of that guy what's the Probie Gnaeus + + + align:start position:0% +of that guy what's the Probie Gnaeus +norm of that diagonal matrix well you're + + align:start position:0% +norm of that diagonal matrix well you're + + + align:start position:0% +norm of that diagonal matrix well you're +supposed to add up the squares of all + + align:start position:0% +supposed to add up the squares of all + + + align:start position:0% +supposed to add up the squares of all +the numbers in the matrix and what do + + align:start position:0% +the numbers in the matrix and what do + + + align:start position:0% +the numbers in the matrix and what do +you get you get that right so that's why + + align:start position:0% +you get you get that right so that's why + + + align:start position:0% +you get you get that right so that's why +this is the same as this because the + + align:start position:0% +this is the same as this because the + + + align:start position:0% +this is the same as this because the +orthogonal guy there on the orthogonal + + align:start position:0% +orthogonal guy there on the orthogonal + + + align:start position:0% +orthogonal guy there on the orthogonal +guy there make no difference in the norm + + align:start position:0% +guy there make no difference in the norm + + + align:start position:0% +guy there make no difference in the norm +but that takes checking right yeah but + + align:start position:0% +but that takes checking right yeah but + + + align:start position:0% +but that takes checking right yeah but +that's another way to see why the + + align:start position:0% +that's another way to see why the + + + align:start position:0% +that's another way to see why the +provenience norm gives this and then + + align:start position:0% +provenience norm gives this and then + + + align:start position:0% +provenience norm gives this and then +finally this was the nuclear norm and + + align:start position:0% +finally this was the nuclear norm and + + + align:start position:0% +finally this was the nuclear norm and +actually just before the my lunch + + align:start position:0% +actually just before the my lunch + + + align:start position:0% +actually just before the my lunch +lecture on the subject of probably about + + align:start position:0% +lecture on the subject of probably about + + + align:start position:0% +lecture on the subject of probably about +a learning morning the lunch lecture was + + align:start position:0% +a learning morning the lunch lecture was + + + align:start position:0% +a learning morning the lunch lecture was +about this crazy way that humans behave + + align:start position:0% +about this crazy way that humans behave + + + align:start position:0% +about this crazy way that humans behave +not us but other humans other actually + + align:start position:0% +not us but other humans other actually + + + align:start position:0% +not us but other humans other actually +well take that out of the tape yeah okay + + align:start position:0% +well take that out of the tape yeah okay + + + align:start position:0% +well take that out of the tape yeah okay +anyway that was that lecture well before + + align:start position:0% +anyway that was that lecture well before + + + align:start position:0% +anyway that was that lecture well before +that was a lecture for an hour plus + + align:start position:0% +that was a lecture for an hour plus + + + align:start position:0% +that was a lecture for an hour plus +about deep learning by somebody who + + align:start position:0% +about deep learning by somebody who + + + align:start position:0% +about deep learning by somebody who +really really has begun to understand + + align:start position:0% +really really has begun to understand + + + align:start position:0% +really really has begun to understand +what is happening inside how does that + + align:start position:0% +what is happening inside how does that + + + align:start position:0% +what is happening inside how does that +gradient descent optimization algorithm + + align:start position:0% +gradient descent optimization algorithm + + + align:start position:0% +gradient descent optimization algorithm +pick out what what does it pick out as + + align:start position:0% +pick out what what does it pick out as + + + align:start position:0% +pick out what what does it pick out as +that as as the thing it learns it's + + align:start position:0% +that as as the thing it learns it's + + + align:start position:0% +that as as the thing it learns it's +gonna be the you know our goal in in + + align:start position:0% +gonna be the you know our goal in in + + + align:start position:0% +gonna be the you know our goal in in +this course we're not there yet but his + + align:start position:0% +this course we're not there yet but his + + + align:start position:0% +this course we're not there yet but his +conjecture is that that yeah so it's a + + align:start position:0% +conjecture is that that yeah so it's a + + + align:start position:0% +conjecture is that that yeah so it's a +conjecture he doesn't have our proof + + align:start position:0% +conjecture he doesn't have our proof + + + align:start position:0% +conjecture he doesn't have our proof +he's got proofs of some nice cases where + + align:start position:0% +he's got proofs of some nice cases where + + + align:start position:0% +he's got proofs of some nice cases where +things commute but he hasn't got the + + align:start position:0% +things commute but he hasn't got the + + + align:start position:0% +things commute but he hasn't got the +whole thing yet but it's pretty terrific + + align:start position:0% +whole thing yet but it's pretty terrific + + + align:start position:0% +whole thing yet but it's pretty terrific +work so this this was professor cerebro + + align:start position:0% + + + + align:start position:0% + +in Chicago so he just announced his + + align:start position:0% +in Chicago so he just announced his + + + align:start position:0% +in Chicago so he just announced his +conjecture and his conjecture is that in + + align:start position:0% +conjecture and his conjecture is that in + + + align:start position:0% +conjecture and his conjecture is that in +a model case the deep learning that + + align:start position:0% +a model case the deep learning that + + + align:start position:0% +a model case the deep learning that +we'll learn about with a gradient + + align:start position:0% +we'll learn about with a gradient + + + align:start position:0% +we'll learn about with a gradient +descent that we'll learn about to find + + align:start position:0% +descent that we'll learn about to find + + + align:start position:0% +descent that we'll learn about to find +the best weights that the point is that + + align:start position:0% +the best weights that the point is that + + + align:start position:0% +the best weights that the point is that +they're you know typical deep learning + + align:start position:0% +they're you know typical deep learning + + + align:start position:0% +they're you know typical deep learning +problem these days there are many more + + align:start position:0% +problem these days there are many more + + + align:start position:0% +problem these days there are many more +ways than samples and so there are a lot + + align:start position:0% +ways than samples and so there are a lot + + + align:start position:0% +ways than samples and so there are a lot +of possible minima + + align:start position:0% +of possible minima + + + align:start position:0% +of possible minima +many different weights give the same + + align:start position:0% +many different weights give the same + + + align:start position:0% +many different weights give the same +minimum loss because there are so many + + align:start position:0% +minimum loss because there are so many + + + align:start position:0% +minimum loss because there are so many +weights it's the problem is like too + + align:start position:0% +weights it's the problem is like too + + + align:start position:0% +weights it's the problem is like too +many variables but it turns out to be a + + align:start position:0% +many variables but it turns out to be a + + + align:start position:0% +many variables but it turns out to be a +very very good thing that's part of the + + align:start position:0% +very very good thing that's part of the + + + align:start position:0% +very very good thing that's part of the +success and the he believes that in a + + align:start position:0% +success and the he believes that in a + + + align:start position:0% +success and the he believes that in a +model situation that the optimization by + + align:start position:0% +model situation that the optimization by + + + align:start position:0% +model situation that the optimization by +gradient descent picks out the weights + + align:start position:0% +gradient descent picks out the weights + + + align:start position:0% +gradient descent picks out the weights +that minimize the nuclear norm so this + + align:start position:0% +that minimize the nuclear norm so this + + + align:start position:0% +that minimize the nuclear norm so this +would be a norm of a lot of weights and + + align:start position:0% +would be a norm of a lot of weights and + + + align:start position:0% +would be a norm of a lot of weights and +he thinks that's where the system goes + + align:start position:0% +he thinks that's where the system goes + + + align:start position:0% +he thinks that's where the system goes +will see this this was comes up in + + align:start position:0% +will see this this was comes up in + + + align:start position:0% +will see this this was comes up in +compressed sensing as I mentioned last + + align:start position:0% +compressed sensing as I mentioned last + + + align:start position:0% +compressed sensing as I mentioned last +time so this but now I have to remember + + align:start position:0% +time so this but now I have to remember + + + align:start position:0% +time so this but now I have to remember +what was what was the definition well do + + align:start position:0% +what was what was the definition well do + + + align:start position:0% +what was what was the definition well do +you remember what the nuclear norm was + + align:start position:0% +you remember what the nuclear norm was + + + align:start position:0% +you remember what the nuclear norm was +it's also his he often used he used a + + align:start position:0% +it's also his he often used he used a + + + align:start position:0% +it's also his he often used he used a +little star instead of an end I'll put + + align:start position:0% +little star instead of an end I'll put + + + align:start position:0% +little star instead of an end I'll put +that in the notes other people call it + + align:start position:0% +that in the notes other people call it + + + align:start position:0% +that in the notes other people call it +the trace norm that's but I think this + + align:start position:0% +the trace norm that's but I think this + + + align:start position:0% +the trace norm that's but I think this +end kind of gives it a name notation you + + align:start position:0% +end kind of gives it a name notation you + + + align:start position:0% +end kind of gives it a name notation you +can remember so let's call it the + + align:start position:0% +can remember so let's call it the + + + align:start position:0% +can remember so let's call it the +nuclear norm do you remember what that + + align:start position:0% +nuclear norm do you remember what that + + + align:start position:0% +nuclear norm do you remember what that +one was + + align:start position:0% +one was + + + align:start position:0% +one was +it was yes somebody's singing it right + + align:start position:0% +it was yes somebody's singing it right + + + align:start position:0% +it was yes somebody's singing it right +add the Sigma's yeah just the sum of the + + align:start position:0% +add the Sigma's yeah just the sum of the + + + align:start position:0% +add the Sigma's yeah just the sum of the +signals like you know one norm yeah this + + align:start position:0% +signals like you know one norm yeah this + + + align:start position:0% +signals like you know one norm yeah this +is natural sort of l1 type of norm for + + align:start position:0% +is natural sort of l1 type of norm for + + + align:start position:0% +is natural sort of l1 type of norm for +matrices + + align:start position:0% +matrices + + + align:start position:0% +matrices +it's the l1 norm you have that Sigma + + align:start position:0% +it's the l1 norm you have that Sigma + + + align:start position:0% +it's the l1 norm you have that Sigma +vector this would be the l2 norm of the + + align:start position:0% +vector this would be the l2 norm of the + + + align:start position:0% +vector this would be the l2 norm of the +Sigma factor that would be the L + + align:start position:0% +Sigma factor that would be the L + + + align:start position:0% +Sigma factor that would be the L +infinity norm notice that the vector + + align:start position:0% +infinity norm notice that the vector + + + align:start position:0% +infinity norm notice that the vector +numbers infinity to 1 gets changed + + align:start position:0% +numbers infinity to 1 gets changed + + + align:start position:0% +numbers infinity to 1 gets changed +around 2 when you look at the matrix + + align:start position:0% +around 2 when you look at the matrix + + + align:start position:0% +around 2 when you look at the matrix +well so that's an exciting idea and it + + align:start position:0% +well so that's an exciting idea and it + + + align:start position:0% +well so that's an exciting idea and it +remains to be proved people are + + align:start position:0% +remains to be proved people are + + + align:start position:0% +remains to be proved people are +experimenting to see does it say is it + + align:start position:0% +experimenting to see does it say is it + + + align:start position:0% +experimenting to see does it say is it +true + + align:start position:0% +true + + + align:start position:0% +true +yep so that's a future yes okay so + + align:start position:0% +yep so that's a future yes okay so + + + align:start position:0% +yep so that's a future yes okay so +that's today we've talked about norms + + align:start position:0% +that's today we've talked about norms + + + align:start position:0% +that's today we've talked about norms +and this section of the notes will be + + align:start position:0% +and this section of the notes will be + + + align:start position:0% +and this section of the notes will be +all about norms we've taken a big leap + + align:start position:0% +all about norms we've taken a big leap + + + align:start position:0% +all about norms we've taken a big leap +in to comment about deep learning and + + align:start position:0% + + + + align:start position:0% + +this is what I want to say the most and + + align:start position:0% +this is what I want to say the most and + + + align:start position:0% +this is what I want to say the most and +I say it to every class I teach at the + + align:start position:0% +I say it to every class I teach at the + + + align:start position:0% +I say it to every class I teach at the +near the start of the semester my + + align:start position:0% +near the start of the semester my + + + align:start position:0% +near the start of the semester my +feeling about what my job is is to teach + + align:start position:0% +feeling about what my job is is to teach + + + align:start position:0% +feeling about what my job is is to teach +you things or to join you join with you + + align:start position:0% +you things or to join you join with you + + + align:start position:0% +you things or to join you join with you +in learning things as has happened today + + align:start position:0% +in learning things as has happened today + + + align:start position:0% +in learning things as has happened today +it's not to grade you I don't spend any + + align:start position:0% +it's not to grade you I don't spend any + + + align:start position:0% +it's not to grade you I don't spend any +time like like losing sleep y'all should + + align:start position:0% +time like like losing sleep y'all should + + + align:start position:0% +time like like losing sleep y'all should +should that person take up one point or + + align:start position:0% +should that person take up one point or + + + align:start position:0% +should that person take up one point or +epsilon penalty for for turning it in + + align:start position:0% +epsilon penalty for for turning it in + + + align:start position:0% +epsilon penalty for for turning it in +for minutes late + + align:start position:0% +for minutes late + + + align:start position:0% +for minutes late +hello with that right we've got a lot to + + align:start position:0% +hello with that right we've got a lot to + + + align:start position:0% +hello with that right we've got a lot to +do here and so anyway we'll get on with + + align:start position:0% +do here and so anyway we'll get on with + + + align:start position:0% +do here and so anyway we'll get on with +a job so homework three coming up and we + + align:start position:0% +a job so homework three coming up and we + + + align:start position:0% +a job so homework three coming up and we +be using the notes that you already have + + align:start position:0% +be using the notes that you already have + + + align:start position:0% +be using the notes that you already have +posted in stellar four for those + + align:start position:0% +posted in stellar four for those + + + align:start position:0% +posted in stellar four for those +sections eight and nine and so on and + + align:start position:0% +sections eight and nine and so on and + + + align:start position:0% +sections eight and nine and so on and +we'll keep going on Monday okay see you + + align:start position:0% +we'll keep going on Monday okay see you + + + align:start position:0% +we'll keep going on Monday okay see you +Monday and have a great weekend + + align:start position:0% + + + + align:start position:0% + +you \ No newline at end of file diff --git a/O3hI9FdxFOM.txt b/O3hI9FdxFOM.txt new file mode 100644 index 0000000000000000000000000000000000000000..fae17fa871da531efce94c521d63bc457097f3dd --- /dev/null +++ b/O3hI9FdxFOM.txt @@ -0,0 +1,13639 @@ +align:start position:0% + +good + + align:start position:0% + + + + align:start position:0% + +morning looks like uh 9:30 is getting + + align:start position:0% +morning looks like uh 9:30 is getting + + + align:start position:0% +morning looks like uh 9:30 is getting +earlier and earlier for everyone hello + + align:start position:0% +earlier and earlier for everyone hello + + + align:start position:0% +earlier and earlier for everyone hello +to all the people watching at + + align:start position:0% + + + + align:start position:0% + +home I I think there should be a + + align:start position:0% +home I I think there should be a + + + align:start position:0% +home I I think there should be a +requirement that if you're watching the + + align:start position:0% +requirement that if you're watching the + + + align:start position:0% +requirement that if you're watching the +video you can only watch it 9:30 to 11: + + align:start position:0% +video you can only watch it 9:30 to 11: + + + align:start position:0% +video you can only watch it 9:30 to 11: +on + + align:start position:0% +on + + + align:start position:0% +on +somay that just to or at least start + + align:start position:0% +somay that just to or at least start + + + align:start position:0% +somay that just to or at least start +watching + + align:start position:0% +watching + + + align:start position:0% +watching +that just so you can all feel our our + + align:start position:0% +that just so you can all feel our our + + + align:start position:0% +that just so you can all feel our our +warnings um today we're going to talk + + align:start position:0% +warnings um today we're going to talk + + + align:start position:0% +warnings um today we're going to talk +about balance search trees now we've + + align:start position:0% +about balance search trees now we've + + + align:start position:0% +about balance search trees now we've +hinted at this for a while um our goal + + align:start position:0% +hinted at this for a while um our goal + + + align:start position:0% +hinted at this for a while um our goal +today is to get a search tree data + + align:start position:0% +today is to get a search tree data + + + align:start position:0% +today is to get a search tree data +structure so we can insert delete and + + align:start position:0% +structure so we can insert delete and + + + align:start position:0% +structure so we can insert delete and +search all in log n time per operation + + align:start position:0% +search all in log n time per operation + + + align:start position:0% +search all in log n time per operation +so we want a tree that's guaranteed to + + align:start position:0% +so we want a tree that's guaranteed to + + + align:start position:0% +so we want a tree that's guaranteed to +be log n in + + align:start position:0% +be log n in + + + align:start position:0% +be log n in +height so uh that's a balanced search + + align:start position:0% +height so uh that's a balanced search + + + align:start position:0% +height so uh that's a balanced search +tree data structure + + align:start position:0% + + + + align:start position:0% + +we want a data structure that can + + align:start position:0% +we want a data structure that can + + + align:start position:0% +we want a data structure that can +maintain a dynamic set of n elements in + + align:start position:0% +maintain a dynamic set of n elements in + + + align:start position:0% +maintain a dynamic set of n elements in +log n time PR operation + + align:start position:0% + + + + align:start position:0% + +so we'll say using a tree of height + + align:start position:0% +so we'll say using a tree of height + + + align:start position:0% +so we'll say using a tree of height +order log + + align:start position:0% + + + + align:start position:0% + +n now uh if you look very closely we + + align:start position:0% +n now uh if you look very closely we + + + align:start position:0% +n now uh if you look very closely we +haven't actually defined what a search + + align:start position:0% +haven't actually defined what a search + + + align:start position:0% +haven't actually defined what a search +tree data structure is we've defined + + align:start position:0% +tree data structure is we've defined + + + align:start position:0% +tree data structure is we've defined +what a binary search tree data structure + + align:start position:0% +what a binary search tree data structure + + + align:start position:0% +what a binary search tree data structure +is and that's one particular kind and + + align:start position:0% +is and that's one particular kind and + + + align:start position:0% +is and that's one particular kind and +that's what we'll be focusing on today + + align:start position:0% +that's what we'll be focusing on today + + + align:start position:0% +that's what we'll be focusing on today +in recitation on Friday we'll look at uh + + align:start position:0% +in recitation on Friday we'll look at uh + + + align:start position:0% +in recitation on Friday we'll look at uh +or you will look cat balance search + + align:start position:0% +or you will look cat balance search + + + align:start position:0% +or you will look cat balance search +trees that are not necessarily binary + + align:start position:0% +trees that are not necessarily binary + + + align:start position:0% +trees that are not necessarily binary +they can have each node can have a + + align:start position:0% +they can have each node can have a + + + align:start position:0% +they can have each node can have a +constant number of children not just two + + align:start position:0% +constant number of children not just two + + + align:start position:0% +constant number of children not just two +okay so I'm defining this generally + + align:start position:0% +okay so I'm defining this generally + + + align:start position:0% +okay so I'm defining this generally +you'll actually see what a search tree + + align:start position:0% +you'll actually see what a search tree + + + align:start position:0% +you'll actually see what a search tree +is in the general case later on today + + align:start position:0% +is in the general case later on today + + + align:start position:0% +is in the general case later on today +we'll just be focusing on the binary + + align:start position:0% +we'll just be focusing on the binary + + + align:start position:0% +we'll just be focusing on the binary +case so I won't Define this + + align:start position:0% +case so I won't Define this + + + align:start position:0% +case so I won't Define this +yet there are a lot of different balance + + align:start position:0% +yet there are a lot of different balance + + + align:start position:0% +yet there are a lot of different balance +search tree data + + align:start position:0% + + + + align:start position:0% + +structures so these are the main ones + + align:start position:0% +structures so these are the main ones + + + align:start position:0% +structures so these are the main ones +that I know of the first one was AVL + + align:start position:0% +that I know of the first one was AVL + + + align:start position:0% +that I know of the first one was AVL +trees this was invented in + + align:start position:0% +trees this was invented in + + + align:start position:0% +trees this was invented in +1962 so that was the beginning of fast + + align:start position:0% +1962 so that was the beginning of fast + + + align:start position:0% +1962 so that was the beginning of fast +data + + align:start position:0% + + + + align:start position:0% + +structures the next three sort of come + + align:start position:0% +structures the next three sort of come + + + align:start position:0% +structures the next three sort of come +together and this is what you'll cover + + align:start position:0% +together and this is what you'll cover + + + align:start position:0% +together and this is what you'll cover +in + + align:start position:0% + + + + align:start position:0% + +recitation this week so uh these are + + align:start position:0% +recitation this week so uh these are + + + align:start position:0% +recitation this week so uh these are +non-binary trees instead of binary we + + align:start position:0% +non-binary trees instead of binary we + + + align:start position:0% +non-binary trees instead of binary we +have have maybe binary and tertiary or + + align:start position:0% +have have maybe binary and tertiary or + + + align:start position:0% +have have maybe binary and tertiary or +binary or tertiary or + + align:start position:0% +binary or tertiary or + + + align:start position:0% +binary or tertiary or +cautionary uh or a general constant + + align:start position:0% +cautionary uh or a general constant + + + align:start position:0% +cautionary uh or a general constant +degree + + align:start position:0% +degree + + + align:start position:0% +degree +B uh so that's another way you can get + + align:start position:0% +B uh so that's another way you can get + + + align:start position:0% +B uh so that's another way you can get +balance two three trees were are the + + align:start position:0% +balance two three trees were are the + + + align:start position:0% +balance two three trees were are the +second trees to be invented they were + + align:start position:0% +second trees to be invented they were + + + align:start position:0% +second trees to be invented they were +invented in + + align:start position:0% +invented in + + + align:start position:0% +invented in +1970 by + + align:start position:0% +1970 by + + + align:start position:0% +1970 by +hopcraft uh the trees we'll cover today + + align:start position:0% +hopcraft uh the trees we'll cover today + + + align:start position:0% +hopcraft uh the trees we'll cover today +are called red black + + align:start position:0% +are called red black + + + align:start position:0% +are called red black +trees these are binary search trees + + align:start position:0% +trees these are binary search trees + + + align:start position:0% +trees these are binary search trees +[Music] + + align:start position:0% + + + + align:start position:0% + +and of guaranteed logarithmic + + align:start position:0% +and of guaranteed logarithmic + + + align:start position:0% +and of guaranteed logarithmic +height um then there's some + + align:start position:0% + + + + align:start position:0% + +others so skip lists are ones that we'll + + align:start position:0% +others so skip lists are ones that we'll + + + align:start position:0% +others so skip lists are ones that we'll +cover next + + align:start position:0% + + + + align:start position:0% + +week it's not exactly a tree but it's + + align:start position:0% +week it's not exactly a tree but it's + + + align:start position:0% +week it's not exactly a tree but it's +more or less a tree and one that you'll + + align:start position:0% +more or less a tree and one that you'll + + + align:start position:0% +more or less a tree and one that you'll +see on your problem set this + + align:start position:0% +see on your problem set this + + + align:start position:0% +see on your problem set this +week are + + align:start position:0% +week are + + + align:start position:0% +week are +treps uh + + align:start position:0% +treps uh + + + align:start position:0% +treps uh +which I won't talk too much about here + + align:start position:0% +which I won't talk too much about here + + + align:start position:0% +which I won't talk too much about here +but they're in some sense easier to get + + align:start position:0% +but they're in some sense easier to get + + + align:start position:0% +but they're in some sense easier to get +because they essentially just rely on + + align:start position:0% +because they essentially just rely on + + + align:start position:0% +because they essentially just rely on +the material from last + + align:start position:0% +the material from last + + + align:start position:0% +the material from last +Monday right so on Monday we saw that if + + align:start position:0% +Monday right so on Monday we saw that if + + + align:start position:0% +Monday right so on Monday we saw that if +we just randomly built a binary search + + align:start position:0% +we just randomly built a binary search + + + align:start position:0% +we just randomly built a binary search +tree it's going to have log and height + + align:start position:0% +tree it's going to have log and height + + + align:start position:0% +tree it's going to have log and height +most of the time in expectation so uh + + align:start position:0% +most of the time in expectation so uh + + + align:start position:0% +most of the time in expectation so uh +treeps are a way to make that Dynamic so + + align:start position:0% +treeps are a way to make that Dynamic so + + + align:start position:0% +treeps are a way to make that Dynamic so +that instead of just having a static set + + align:start position:0% +that instead of just having a static set + + + align:start position:0% +that instead of just having a static set +of n items you can insert and delete + + align:start position:0% +of n items you can insert and delete + + + align:start position:0% +of n items you can insert and delete +into those items and still effectively + + align:start position:0% +into those items and still effectively + + + align:start position:0% +into those items and still effectively +randomly prute them and put them in a + + align:start position:0% +randomly prute them and put them in a + + + align:start position:0% +randomly prute them and put them in a +tree + + align:start position:0% +tree + + + align:start position:0% +tree +so in some sense that's the easiest it's + + align:start position:0% +so in some sense that's the easiest it's + + + align:start position:0% +so in some sense that's the easiest it's +also the most one of the most recent + + align:start position:0% +also the most one of the most recent + + + align:start position:0% +also the most one of the most recent +search tree data structures that was + + align:start position:0% +search tree data structures that was + + + align:start position:0% +search tree data structures that was +invented in + + align:start position:0% +invented in + + + align:start position:0% +invented in +1996 by a couple of + + align:start position:0% +1996 by a couple of + + + align:start position:0% +1996 by a couple of +geometers Ryman cidel and Aragon so + + align:start position:0% +geometers Ryman cidel and Aragon so + + + align:start position:0% +geometers Ryman cidel and Aragon so +those are just some search for data + + align:start position:0% +those are just some search for data + + + align:start position:0% +those are just some search for data +structures the only ones we will not + + align:start position:0% +structures the only ones we will not + + + align:start position:0% +structures the only ones we will not +cover in this class are a trees um + + align:start position:0% +cover in this class are a trees um + + + align:start position:0% +cover in this class are a trees um +they're not too hard if you're + + align:start position:0% +they're not too hard if you're + + + align:start position:0% +they're not too hard if you're +interested you should read about them + + align:start position:0% +interested you should read about them + + + align:start position:0% +interested you should read about them +because they're + + align:start position:0% +because they're + + + align:start position:0% +because they're +fun I think they're a problem in in the + + align:start position:0% +fun I think they're a problem in in the + + + align:start position:0% +fun I think they're a problem in in the +textbook okay but today we're going to + + align:start position:0% +textbook okay but today we're going to + + + align:start position:0% +textbook okay but today we're going to +focus on red black + + align:start position:0% + + + + align:start position:0% + +trees + + align:start position:0% +trees + + + align:start position:0% +trees +which it's a fairly simple + + align:start position:0% + + + + align:start position:0% + +idea red black trees and it's a + + align:start position:0% +idea red black trees and it's a + + + align:start position:0% +idea red black trees and it's a +particular way of guaranteeing this + + align:start position:0% +particular way of guaranteeing this + + + align:start position:0% +particular way of guaranteeing this +logarithmic height so that all the + + align:start position:0% +logarithmic height so that all the + + + align:start position:0% +logarithmic height so that all the +operations can be supported in log end + + align:start position:0% +operations can be supported in log end + + + align:start position:0% +operations can be supported in log end +time + + align:start position:0% +time + + + align:start position:0% +time +so they're binary search + + align:start position:0% + + + + align:start position:0% + +trees + + align:start position:0% + + + + align:start position:0% + +and they have a little bit of extra + + align:start position:0% +and they have a little bit of extra + + + align:start position:0% +and they have a little bit of extra +information in each node called the + + align:start position:0% +information in each node called the + + + align:start position:0% +information in each node called the +color field + + align:start position:0% + + + + align:start position:0% + +and there's several properties that a + + align:start position:0% +and there's several properties that a + + + align:start position:0% +and there's several properties that a +tree with color field has to spec has to + + align:start position:0% +tree with color field has to spec has to + + + align:start position:0% +tree with color field has to spec has to +satisfy in order to be called the red + + align:start position:0% +satisfy in order to be called the red + + + align:start position:0% +satisfy in order to be called the red +black tree these are called the red + + align:start position:0% +black tree these are called the red + + + align:start position:0% +black tree these are called the red +black + + align:start position:0% +black + + + align:start position:0% +black +properties and this will take a little + + align:start position:0% +properties and this will take a little + + + align:start position:0% +properties and this will take a little +bit a little bit of time to write down + + align:start position:0% +bit a little bit of time to write down + + + align:start position:0% +bit a little bit of time to write down +but it's all pretty + + align:start position:0% +but it's all pretty + + + align:start position:0% +but it's all pretty +simple so once I write them down I'll + + align:start position:0% +simple so once I write them down I'll + + + align:start position:0% +simple so once I write them down I'll +say what they really mean there's four + + align:start position:0% + + + + align:start position:0% + +properties the first one's pretty simple + + align:start position:0% +properties the first one's pretty simple + + + align:start position:0% +properties the first one's pretty simple +every node is + + align:start position:0% +every node is + + + align:start position:0% +every node is +either red or black that's the hence the + + align:start position:0% +either red or black that's the hence the + + + align:start position:0% +either red or black that's the hence the +name of red black + + align:start position:0% + + + + align:start position:0% + +trees so the color field is just a + + align:start position:0% +trees so the color field is just a + + + align:start position:0% +trees so the color field is just a +single bit specifying red or black and + + align:start position:0% +single bit specifying red or black and + + + align:start position:0% +single bit specifying red or black and +red nodes I'm going to denote by a + + align:start position:0% +red nodes I'm going to denote by a + + + align:start position:0% +red nodes I'm going to denote by a +double circle CU I don't have colored + + align:start position:0% +double circle CU I don't have colored + + + align:start position:0% +double circle CU I don't have colored +chalk here and black nodes will be a + + align:start position:0% +chalk here and black nodes will be a + + + align:start position:0% +chalk here and black nodes will be a +single Circle and you probably don't + + align:start position:0% +single Circle and you probably don't + + + align:start position:0% +single Circle and you probably don't +have colored pens either so save us some + + align:start position:0% +have colored pens either so save us some + + + align:start position:0% +have colored pens either so save us some +grief + + align:start position:0% +grief + + + align:start position:0% +grief +um red is double circle black is single + + align:start position:0% +um red is double circle black is single + + + align:start position:0% +um red is double circle black is single +Circle and we sort of prefer black nodes + + align:start position:0% +Circle and we sort of prefer black nodes + + + align:start position:0% +Circle and we sort of prefer black nodes +in some sense red nodes are a pain as + + align:start position:0% +in some sense red nodes are a pain as + + + align:start position:0% +in some sense red nodes are a pain as +we'll + + align:start position:0% +we'll + + + align:start position:0% +we'll +see okay second + + align:start position:0% +see okay second + + + align:start position:0% +see okay second +property is that the + + align:start position:0% +property is that the + + + align:start position:0% +property is that the +root and the + + align:start position:0% +root and the + + + align:start position:0% +root and the +leaves are all + + align:start position:0% + + + + align:start position:0% + +black and uh I'm going to pull a little + + align:start position:0% +black and uh I'm going to pull a little + + + align:start position:0% +black and uh I'm going to pull a little +trick here or uh treat binary searches a + + align:start position:0% +trick here or uh treat binary searches a + + + align:start position:0% +trick here or uh treat binary searches a +little bit differently than we have in + + align:start position:0% +little bit differently than we have in + + + align:start position:0% +little bit differently than we have in +the past um normally you think of a tree + + align:start position:0% +the past um normally you think of a tree + + + align:start position:0% +the past um normally you think of a tree +as a bunch of nodes each node could have + + align:start position:0% +as a bunch of nodes each node could have + + + align:start position:0% +as a bunch of nodes each node could have +zero or one or two children something + + align:start position:0% +zero or one or two children something + + + align:start position:0% +zero or one or two children something +like this I'm going to imagine appending + + align:start position:0% +like this I'm going to imagine appending + + + align:start position:0% +like this I'm going to imagine appending +every place where a node does not have a + + align:start position:0% +every place where a node does not have a + + + align:start position:0% +every place where a node does not have a +child I'm going to put a little dot here + + align:start position:0% +child I'm going to put a little dot here + + + align:start position:0% +child I'm going to put a little dot here +an external node which I I call a leaf + + align:start position:0% +an external node which I I call a leaf + + + align:start position:0% +an external node which I I call a leaf +so normally leaves would have been these + + align:start position:0% +so normally leaves would have been these + + + align:start position:0% +so normally leaves would have been these +items I'm just going to add to every + + align:start position:0% +items I'm just going to add to every + + + align:start position:0% +items I'm just going to add to every +absent uh child pointer a new leaf and + + align:start position:0% +absent uh child pointer a new leaf and + + + align:start position:0% +absent uh child pointer a new leaf and +these will be my leaves these are really + + align:start position:0% +these will be my leaves these are really + + + align:start position:0% +these will be my leaves these are really +the nil pointers from each of these + + align:start position:0% +the nil pointers from each of these + + + align:start position:0% +the nil pointers from each of these +nodes so now every internal node has + + align:start position:0% +nodes so now every internal node has + + + align:start position:0% +nodes so now every internal node has +exactly two children and every leaf has + + align:start position:0% +exactly two children and every leaf has + + + align:start position:0% +exactly two children and every leaf has +zero children okay so these are the noes + + align:start position:0% +zero children okay so these are the noes + + + align:start position:0% +zero children okay so these are the noes +I'm referring to these guys are black + + align:start position:0% +I'm referring to these guys are black + + + align:start position:0% +I'm referring to these guys are black +and this guy is + + align:start position:0% +and this guy is + + + align:start position:0% +and this guy is +black according to rule + + align:start position:0% +black according to rule + + + align:start position:0% +black according to rule +two now the properties get a little bit + + align:start position:0% +two now the properties get a little bit + + + align:start position:0% +two now the properties get a little bit +more + + align:start position:0% + + + + align:start position:0% + +interesting the parent of every red node + + align:start position:0% +interesting the parent of every red node + + + align:start position:0% +interesting the parent of every red node +is + + align:start position:0% + + + + align:start position:0% + +black so whenever I have a red node its + + align:start position:0% +black so whenever I have a red node its + + + align:start position:0% +black so whenever I have a red node its +parent has to be black a single + + align:start position:0% + + + + align:start position:0% + +Circle okay so in other words if you + + align:start position:0% +Circle okay so in other words if you + + + align:start position:0% +Circle okay so in other words if you +look at a path in the tree you can never + + align:start position:0% +look at a path in the tree you can never + + + align:start position:0% +look at a path in the tree you can never +have two red nodes consecutive has to be + + align:start position:0% +have two red nodes consecutive has to be + + + align:start position:0% +have two red nodes consecutive has to be +can at most alternate red black red + + align:start position:0% +can at most alternate red black red + + + align:start position:0% +can at most alternate red black red +black you can have several black nodes + + align:start position:0% +black you can have several black nodes + + + align:start position:0% +black you can have several black nodes +consecutive but never two red nodes + + align:start position:0% +consecutive but never two red nodes + + + align:start position:0% +consecutive but never two red nodes +okay and then one more + + align:start position:0% +okay and then one more + + + align:start position:0% +okay and then one more +rule says a little bit more about such + + align:start position:0% + + + + align:start position:0% + +paths so if we take a simple path + + align:start position:0% +paths so if we take a simple path + + + align:start position:0% +paths so if we take a simple path +meaning it doesn't repeat any + + align:start position:0% +meaning it doesn't repeat any + + + align:start position:0% +meaning it doesn't repeat any +vertices from a node X to a descendant + + align:start position:0% +vertices from a node X to a descendant + + + align:start position:0% +vertices from a node X to a descendant +leaf + + align:start position:0% + + + + align:start position:0% + +of + + align:start position:0% + + + + align:start position:0% + +X all such pads to all descendant leaves + + align:start position:0% +X all such pads to all descendant leaves + + + align:start position:0% +X all such pads to all descendant leaves +have the same number of black nodes on + + align:start position:0% + + + + align:start position:0% + +them so let me draw a picture we have + + align:start position:0% +them so let me draw a picture we have + + + align:start position:0% +them so let me draw a picture we have +some tree we have some node X in the + + align:start position:0% +some tree we have some node X in the + + + align:start position:0% +some tree we have some node X in the +tree and I'm looking at all the paths + + align:start position:0% +tree and I'm looking at all the paths + + + align:start position:0% +tree and I'm looking at all the paths +from X down to some descendant Leaf down + + align:start position:0% +from X down to some descendant Leaf down + + + align:start position:0% +from X down to some descendant Leaf down +here the bottom of the tree all of these + + align:start position:0% +here the bottom of the tree all of these + + + align:start position:0% +here the bottom of the tree all of these +paths should have the same number of + + align:start position:0% +paths should have the same number of + + + align:start position:0% +paths should have the same number of +black nodes so here I'll draw that each + + align:start position:0% +black nodes so here I'll draw that each + + + align:start position:0% +black nodes so here I'll draw that each +one + + align:start position:0% +one + + + align:start position:0% +one +has uh four black nodes the leaf and + + align:start position:0% +has uh four black nodes the leaf and + + + align:start position:0% +has uh four black nodes the leaf and +three above + + align:start position:0% + + + + align:start position:0% + +it we know that these from property + + align:start position:0% +it we know that these from property + + + align:start position:0% +it we know that these from property +three these nodes don't have at most + + align:start position:0% +three these nodes don't have at most + + + align:start position:0% +three these nodes don't have at most +half of the nodes are red because + + align:start position:0% +half of the nodes are red because + + + align:start position:0% +half of the nodes are red because +whenever I have a red node the parent + + align:start position:0% +whenever I have a red node the parent + + + align:start position:0% +whenever I have a red node the parent +must be black um but I want all of these + + align:start position:0% +must be black um but I want all of these + + + align:start position:0% +must be black um but I want all of these +paths have exactly the same number of + + align:start position:0% +paths have exactly the same number of + + + align:start position:0% +paths have exactly the same number of +black nodes one subtlety here is that + + align:start position:0% +black nodes one subtlety here is that + + + align:start position:0% +black nodes one subtlety here is that +the black height I didn't really leave + + align:start position:0% +the black height I didn't really leave + + + align:start position:0% +the black height I didn't really leave +room so I'll write it over + + align:start position:0% + + + + align:start position:0% + +here this should be the same for all + + align:start position:0% +here this should be the same for all + + + align:start position:0% +here this should be the same for all +paths but in particular the count I'm + + align:start position:0% +paths but in particular the count I'm + + + align:start position:0% +paths but in particular the count I'm +interested in does not include x itself + + align:start position:0% + + + + align:start position:0% + +okay so if x is black I'm only calling + + align:start position:0% +okay so if x is black I'm only calling + + + align:start position:0% +okay so if x is black I'm only calling +the black height so the black height of + + align:start position:0% +the black height so the black height of + + + align:start position:0% +the black height so the black height of +X is this count four and even if x is + + align:start position:0% +X is this count four and even if x is + + + align:start position:0% +X is this count four and even if x is +black I'll the black height is four so + + align:start position:0% +black I'll the black height is four so + + + align:start position:0% +black I'll the black height is four so +these are just some Minor Details to get + + align:start position:0% +these are just some Minor Details to get + + + align:start position:0% +these are just some Minor Details to get +all of the algorithms a bit clean so + + align:start position:0% +all of the algorithms a bit clean so + + + align:start position:0% +all of the algorithms a bit clean so +let's look at an example of a red black + + align:start position:0% + + + + align:start position:0% + +tree so um yeah I'll show you an example + + align:start position:0% +tree so um yeah I'll show you an example + + + align:start position:0% +tree so um yeah I'll show you an example +then I'll say why we care about these + + align:start position:0% +then I'll say why we care about these + + + align:start position:0% +then I'll say why we care about these +properties + + align:start position:0% + + + + align:start position:0% + +okay so this tree has several properties + + align:start position:0% +okay so this tree has several properties + + + align:start position:0% +okay so this tree has several properties +the first thing is that it's a binary + + align:start position:0% +the first thing is that it's a binary + + + align:start position:0% +the first thing is that it's a binary +search tree okay so you can check an in + + align:start position:0% +search tree okay so you can check an in + + + align:start position:0% +search tree okay so you can check an in +order traversal should give these + + align:start position:0% +order traversal should give these + + + align:start position:0% +order traversal should give these +numbers in sorted order 3 7 8 10 11 18 + + align:start position:0% +numbers in sorted order 3 7 8 10 11 18 + + + align:start position:0% +numbers in sorted order 3 7 8 10 11 18 +22 26 so it's a valid binary search tree + + align:start position:0% +22 26 so it's a valid binary search tree + + + align:start position:0% +22 26 so it's a valid binary search tree +we've appended these leaves with no keys + + align:start position:0% +we've appended these leaves with no keys + + + align:start position:0% +we've appended these leaves with no keys +in them they're just hanging around + + align:start position:0% +in them they're just hanging around + + + align:start position:0% +in them they're just hanging around +those are the nil pointers so each of + + align:start position:0% +those are the nil pointers so each of + + + align:start position:0% +those are the nil pointers so each of +these you can call + + align:start position:0% +these you can call + + + align:start position:0% +these you can call +nil uh they're all just marked there + + align:start position:0% +nil uh they're all just marked there + + + align:start position:0% +nil uh they're all just marked there +wherever there's an absent + + align:start position:0% +wherever there's an absent + + + align:start position:0% +wherever there's an absent +child and then I've double circled some + + align:start position:0% +child and then I've double circled some + + + align:start position:0% +child and then I've double circled some +of the nodes to color them red okay if I + + align:start position:0% +of the nodes to color them red okay if I + + + align:start position:0% +of the nodes to color them red okay if I +didn't the black Heights wouldn't match + + align:start position:0% +didn't the black Heights wouldn't match + + + align:start position:0% +didn't the black Heights wouldn't match +up so have to be a little bit careful + + align:start position:0% +up so have to be a little bit careful + + + align:start position:0% +up so have to be a little bit careful +from every node we'd like to measure uh + + align:start position:0% +from every node we'd like to measure uh + + + align:start position:0% +from every node we'd like to measure uh +the number of black nodes from that node + + align:start position:0% +the number of black nodes from that node + + + align:start position:0% +the number of black nodes from that node +down to to any descendant Leaf so for + + align:start position:0% +down to to any descendant Leaf so for + + + align:start position:0% +down to to any descendant Leaf so for +example the nil pointers their black + + align:start position:0% +example the nil pointers their black + + + align:start position:0% +example the nil pointers their black +height is zero good that's always the + + align:start position:0% +height is zero good that's always the + + + align:start position:0% +height is zero good that's always the +answer so these guys all have black + + align:start position:0% +answer so these guys all have black + + + align:start position:0% +answer so these guys all have black +height zero I'll just uh represent that + + align:start position:0% +height zero I'll just uh represent that + + + align:start position:0% +height zero I'll just uh represent that +here black height equals + + align:start position:0% +here black height equals + + + align:start position:0% +here black height equals +zero okay what's the black height of + + align:start position:0% + + + + align:start position:0% + +three zero not not quite cuz these nodes + + align:start position:0% +three zero not not quite cuz these nodes + + + align:start position:0% +three zero not not quite cuz these nodes +are black so the black height is + + align:start position:0% +are black so the black height is + + + align:start position:0% +are black so the black height is +one okay you're right that we don't + + align:start position:0% +one okay you're right that we don't + + + align:start position:0% +one okay you're right that we don't +count three even though it's black uh we + + align:start position:0% +count three even though it's black uh we + + + align:start position:0% +count three even though it's black uh we +it's not included in the count but the + + align:start position:0% +it's not included in the count but the + + + align:start position:0% +it's not included in the count but the +leaves count and you there's only two + + align:start position:0% +leaves count and you there's only two + + + align:start position:0% +leaves count and you there's only two +paths here and they each have the same + + align:start position:0% +paths here and they each have the same + + + align:start position:0% +paths here and they each have the same +number of black nodes as they should uh + + align:start position:0% +number of black nodes as they should uh + + + align:start position:0% +number of black nodes as they should uh +over here let's say eight also has black + + align:start position:0% +over here let's say eight also has black + + + align:start position:0% +over here let's say eight also has black +height one even though it's + + align:start position:0% + + + + align:start position:0% + +red okay same with + + align:start position:0% +red okay same with + + + align:start position:0% +red okay same with +11 same with + + align:start position:0% +11 same with + + + align:start position:0% +11 same with +26 each of them only has two paths each + + align:start position:0% +26 each of them only has two paths each + + + align:start position:0% +26 each of them only has two paths each +of them has each path has one black note + + align:start position:0% +of them has each path has one black note + + + align:start position:0% +of them has each path has one black note +on it uh 10 + + align:start position:0% +on it uh 10 + + + align:start position:0% +on it uh 10 +what's the black + + align:start position:0% +what's the black + + + align:start position:0% +what's the black +height still one + + align:start position:0% +height still one + + + align:start position:0% +height still one +good cuz we don't count 10 at there's + + align:start position:0% +good cuz we don't count 10 at there's + + + align:start position:0% +good cuz we don't count 10 at there's +now four paths to leaves each of them + + align:start position:0% +now four paths to leaves each of them + + + align:start position:0% +now four paths to leaves each of them +contains exactly one black node plus the + + align:start position:0% +contains exactly one black node plus the + + + align:start position:0% +contains exactly one black node plus the +root which we don't count 22 same thing + + align:start position:0% +root which we don't count 22 same thing + + + align:start position:0% +root which we don't count 22 same thing +hopefully okay this is getting a little + + align:start position:0% +hopefully okay this is getting a little + + + align:start position:0% +hopefully okay this is getting a little +more interesting there's one path here + + align:start position:0% +more interesting there's one path here + + + align:start position:0% +more interesting there's one path here +which has one black node there's other + + align:start position:0% +which has one black node there's other + + + align:start position:0% +which has one black node there's other +paths here which are longer but they + + align:start position:0% +paths here which are longer but they + + + align:start position:0% +paths here which are longer but they +still only have one black node so if we + + align:start position:0% +still only have one black node so if we + + + align:start position:0% +still only have one black node so if we +just sort of ignore the red nodes all + + align:start position:0% +just sort of ignore the red nodes all + + + align:start position:0% +just sort of ignore the red nodes all +these pads have the same length Okay 18 + + align:start position:0% +these pads have the same length Okay 18 + + + align:start position:0% +these pads have the same length Okay 18 +should be bigger hopefully black height + + align:start position:0% +should be bigger hopefully black height + + + align:start position:0% +should be bigger hopefully black height +of + + align:start position:0% +of + + + align:start position:0% +of +two because each of these paths now has + + align:start position:0% +two because each of these paths now has + + + align:start position:0% +two because each of these paths now has +one black note here one black note in + + align:start position:0% +one black note here one black note in + + + align:start position:0% +one black note here one black note in +the leaves or one black note here and + + align:start position:0% +the leaves or one black note here and + + + align:start position:0% +the leaves or one black note here and +one black note in the leaves and finally + + align:start position:0% +one black note in the leaves and finally + + + align:start position:0% +one black note in the leaves and finally +the root should have a black height + + align:start position:0% +the root should have a black height + + + align:start position:0% +the root should have a black height +of two easier to see over here I guess + + align:start position:0% +of two easier to see over here I guess + + + align:start position:0% +of two easier to see over here I guess +each of these pths has two black nodes + + align:start position:0% +each of these pths has two black nodes + + + align:start position:0% +each of these pths has two black nodes +same over + + align:start position:0% +same over + + + align:start position:0% +same over +here okay um + + align:start position:0% +here okay um + + + align:start position:0% +here okay um +so that's just hopefully these + + align:start position:0% +so that's just hopefully these + + + align:start position:0% +so that's just hopefully these +properties make sense we didn't check + + align:start position:0% +properties make sense we didn't check + + + align:start position:0% +properties make sense we didn't check +all of them every red node has a black + + align:start position:0% +all of them every red node has a black + + + align:start position:0% +all of them every red node has a black +parent you look at all of these paths um + + align:start position:0% +parent you look at all of these paths um + + + align:start position:0% +parent you look at all of these paths um +we sort of alternate red black at most + + align:start position:0% +we sort of alternate red black at most + + + align:start position:0% +we sort of alternate red black at most +or we have just a bunch of blacks but we + + align:start position:0% +or we have just a bunch of blacks but we + + + align:start position:0% +or we have just a bunch of blacks but we +never repeat Two Reds in a row uh the + + align:start position:0% +never repeat Two Reds in a row uh the + + + align:start position:0% +never repeat Two Reds in a row uh the +root and the leaves are black that we + + align:start position:0% +root and the leaves are black that we + + + align:start position:0% +root and the leaves are black that we +used pretty much by definition every + + align:start position:0% +used pretty much by definition every + + + align:start position:0% +used pretty much by definition every +note is red or black okay that's + + align:start position:0% +note is red or black okay that's + + + align:start position:0% +note is red or black okay that's +easy um this is a particular set of + + align:start position:0% +easy um this is a particular set of + + + align:start position:0% +easy um this is a particular set of +properties that may seem a bit arbitrary + + align:start position:0% +properties that may seem a bit arbitrary + + + align:start position:0% +properties that may seem a bit arbitrary +at this point they will make sense a lot + + align:start position:0% +at this point they will make sense a lot + + + align:start position:0% +at this point they will make sense a lot +more sense as we see what consequences + + align:start position:0% +more sense as we see what consequences + + + align:start position:0% +more sense as we see what consequences +they have but there are a couple of + + align:start position:0% +they have but there are a couple of + + + align:start position:0% +they have but there are a couple of +goals that we're trying to achieve here + + align:start position:0% +goals that we're trying to achieve here + + + align:start position:0% +goals that we're trying to achieve here +one is that these properties should + + align:start position:0% +one is that these properties should + + + align:start position:0% +one is that these properties should +force the tree to have logarithmic + + align:start position:0% +force the tree to have logarithmic + + + align:start position:0% +force the tree to have logarithmic +height order log and height and they do + + align:start position:0% +height order log and height and they do + + + align:start position:0% +height order log and height and they do +although that's probably not obvious at + + align:start position:0% +although that's probably not obvious at + + + align:start position:0% +although that's probably not obvious at +this point it follows mainly from this + + align:start position:0% +this point it follows mainly from this + + + align:start position:0% +this point it follows mainly from this +prop uh from property well from all the + + align:start position:0% +prop uh from property well from all the + + + align:start position:0% +prop uh from property well from all the +properties three and four are the main + + align:start position:0% +properties three and four are the main + + + align:start position:0% +properties three and four are the main +ones but you pretty much need all of + + align:start position:0% +ones but you pretty much need all of + + + align:start position:0% +ones but you pretty much need all of +them the other thing the other uh desire + + align:start position:0% +them the other thing the other uh desire + + + align:start position:0% +them the other thing the other uh desire +we have from these properties is that + + align:start position:0% +we have from these properties is that + + + align:start position:0% +we have from these properties is that +they're somehow easy to maintain okay I + + align:start position:0% +they're somehow easy to maintain okay I + + + align:start position:0% +they're somehow easy to maintain okay I +can create a tree in the beginning that + + align:start position:0% +can create a tree in the beginning that + + + align:start position:0% +can create a tree in the beginning that +has this property for example I could + + align:start position:0% +has this property for example I could + + + align:start position:0% +has this property for example I could +make I have to be a little bit careful + + align:start position:0% +make I have to be a little bit careful + + + align:start position:0% +make I have to be a little bit careful +but I could make certainly if I take a + + align:start position:0% +but I could make certainly if I take a + + + align:start position:0% +but I could make certainly if I take a +perfectly balanced binary tree and make + + align:start position:0% +perfectly balanced binary tree and make + + + align:start position:0% +perfectly balanced binary tree and make +all of the nodes black it will satisfy + + align:start position:0% +all of the nodes black it will satisfy + + + align:start position:0% +all of the nodes black it will satisfy +those + + align:start position:0% +those + + + align:start position:0% +those +properties okay this is a red black + + align:start position:0% + + + + align:start position:0% + +tree okay so it's not too hard to make + + align:start position:0% +tree okay so it's not too hard to make + + + align:start position:0% +tree okay so it's not too hard to make +these properties hold just from the + + align:start position:0% +these properties hold just from the + + + align:start position:0% +these properties hold just from the +beginning + + align:start position:0% +beginning + + + align:start position:0% +beginning +the tricky part is to maintain them when + + align:start position:0% +the tricky part is to maintain them when + + + align:start position:0% +the tricky part is to maintain them when +I insert a node into this tree and + + align:start position:0% +I insert a node into this tree and + + + align:start position:0% +I insert a node into this tree and +delete a node from this tree I want to + + align:start position:0% +delete a node from this tree I want to + + + align:start position:0% +delete a node from this tree I want to +guarant I want to make it not too hard + + align:start position:0% +guarant I want to make it not too hard + + + align:start position:0% +guarant I want to make it not too hard +in login time I've got to be able to + + align:start position:0% +in login time I've got to be able to + + + align:start position:0% +in login time I've got to be able to +restore all these + + align:start position:0% +restore all these + + + align:start position:0% +restore all these +properties okay that will be the hardest + + align:start position:0% +properties okay that will be the hardest + + + align:start position:0% +properties okay that will be the hardest +part the first thing we'll do is prove + + align:start position:0% +part the first thing we'll do is prove + + + align:start position:0% +part the first thing we'll do is prove +that these properties imply that the + + align:start position:0% +that these properties imply that the + + + align:start position:0% +that these properties imply that the +tree has to have height order Logan + + align:start position:0% +tree has to have height order Logan + + + align:start position:0% +tree has to have height order Logan +therefore all searches and queries on + + align:start position:0% +therefore all searches and queries on + + + align:start position:0% +therefore all searches and queries on +that data structure will run fast then + + align:start position:0% +that data structure will run fast then + + + align:start position:0% +that data structure will run fast then +the hard part will be to make sure these + + align:start position:0% +the hard part will be to make sure these + + + align:start position:0% +the hard part will be to make sure these +properties stay true if they initially + + align:start position:0% +properties stay true if they initially + + + align:start position:0% +properties stay true if they initially +held true when we make changes to the + + align:start position:0% + + + + align:start position:0% + +tree + + align:start position:0% + + + + align:start position:0% + +so let's look at the height of a red + + align:start position:0% +so let's look at the height of a red + + + align:start position:0% +so let's look at the height of a red +black tree + + align:start position:0% + + + + align:start position:0% + +and from this we'll start to see why + + align:start position:0% +and from this we'll start to see why + + + align:start position:0% +and from this we'll start to see why +these why where these properties come + + align:start position:0% +these why where these properties come + + + align:start position:0% +these why where these properties come +from why we chose these properties + + align:start position:0% + + + + align:start position:0% + +so the claim is that a height of a red + + align:start position:0% +so the claim is that a height of a red + + + align:start position:0% +so the claim is that a height of a red +black tree with n keys so I'm not saying + + align:start position:0% +black tree with n keys so I'm not saying + + + align:start position:0% +black tree with n keys so I'm not saying +nodes here because I really only want to + + align:start position:0% +nodes here because I really only want to + + + align:start position:0% +nodes here because I really only want to +count the internal nodes not these extra + + align:start position:0% +count the internal nodes not these extra + + + align:start position:0% +count the internal nodes not these extra +leaves that we've added has height at + + align:start position:0% +leaves that we've added has height at + + + align:start position:0% +leaves that we've added has height at +most 2 * log of n plus one so order log + + align:start position:0% + + + + align:start position:0% + +n but we have a pretty precise bound of + + align:start position:0% +n but we have a pretty precise bound of + + + align:start position:0% +n but we have a pretty precise bound of +factor of + + align:start position:0% +factor of + + + align:start position:0% +factor of +two there's a proof of this in the + + align:start position:0% +two there's a proof of this in the + + + align:start position:0% +two there's a proof of this in the +textbook uh by induction and you should + + align:start position:0% +textbook uh by induction and you should + + + align:start position:0% +textbook uh by induction and you should +read + + align:start position:0% +read + + + align:start position:0% +read +that what I'm going to give is more of a + + align:start position:0% +that what I'm going to give is more of a + + + align:start position:0% +that what I'm going to give is more of a +proof + + align:start position:0% + + + + align:start position:0% + +sketch you should read the proof by + + align:start position:0% +sketch you should read the proof by + + + align:start position:0% +sketch you should read the proof by +induction because all the practice you + + align:start position:0% +induction because all the practice you + + + align:start position:0% +induction because all the practice you +can get with proof by induction is good + + align:start position:0% +can get with proof by induction is good + + + align:start position:0% +can get with proof by induction is good +the proof sketch on the other hand gives + + align:start position:0% +the proof sketch on the other hand gives + + + align:start position:0% +the proof sketch on the other hand gives +a lot more intuition of what's going on + + align:start position:0% +a lot more intuition of what's going on + + + align:start position:0% +a lot more intuition of what's going on +with red red black trees and connects up + + align:start position:0% +with red red black trees and connects up + + + align:start position:0% +with red red black trees and connects up +with recitation on Friday so let me tell + + align:start position:0% +with recitation on Friday so let me tell + + + align:start position:0% +with recitation on Friday so let me tell +you that + + align:start position:0% +you that + + + align:start position:0% +you that +instead um I'm going to leave that board + + align:start position:0% +instead um I'm going to leave that board + + + align:start position:0% +instead um I'm going to leave that board +blank and go over + + align:start position:0% + + + + align:start position:0% + +here so + + align:start position:0% +here so + + + align:start position:0% +here so +uh the first thing I'm going to do this + + align:start position:0% +uh the first thing I'm going to do this + + + align:start position:0% +uh the first thing I'm going to do this +is sort of I'm going to manipulate this + + align:start position:0% +is sort of I'm going to manipulate this + + + align:start position:0% +is sort of I'm going to manipulate this +tree until it looks like something that + + align:start position:0% +tree until it looks like something that + + + align:start position:0% +tree until it looks like something that +I know the first thing I'm or the the + + align:start position:0% +I know the first thing I'm or the the + + + align:start position:0% +I know the first thing I'm or the the +main change I'm going to + + align:start position:0% +main change I'm going to + + + align:start position:0% +main change I'm going to +make is to merge each red node into its + + align:start position:0% +make is to merge each red node into its + + + align:start position:0% +make is to merge each red node into its +parent and we know that the parent of a + + align:start position:0% +parent and we know that the parent of a + + + align:start position:0% +parent and we know that the parent of a +red node must be + + align:start position:0% + + + + align:start position:0% + +black so merge each red Noe into its + + align:start position:0% +black so merge each red Noe into its + + + align:start position:0% +black so merge each red Noe into its +black + + align:start position:0% +black + + + align:start position:0% +black +parent so let's look at that here so I'm + + align:start position:0% +parent so let's look at that here so I'm + + + align:start position:0% +parent so let's look at that here so I'm +going to take this red node merge it + + align:start position:0% +going to take this red node merge it + + + align:start position:0% +going to take this red node merge it +into its parent take this red node merge + + align:start position:0% +into its parent take this red node merge + + + align:start position:0% +into its parent take this red node merge +it into its parent and so on there's one + + align:start position:0% +it into its parent and so on there's one + + + align:start position:0% +it into its parent and so on there's one +up there which I can't reach but I'm + + align:start position:0% +up there which I can't reach but I'm + + + align:start position:0% +up there which I can't reach but I'm +going to redraw this picture now so + + align:start position:0% +going to redraw this picture now so + + + align:start position:0% +going to redraw this picture now so +seven so the top node now becomes in + + align:start position:0% +seven so the top node now becomes in + + + align:start position:0% +seven so the top node now becomes in +some sense seven and + + align:start position:0% +some sense seven and + + + align:start position:0% +some sense seven and +18 they got merged together but no one + + align:start position:0% +18 they got merged together but no one + + + align:start position:0% +18 they got merged together but no one +else joined them then on the left we + + align:start position:0% +else joined them then on the left we + + + align:start position:0% +else joined them then on the left we +have + + align:start position:0% +have + + + align:start position:0% +have +three okay nothing join that and there's + + align:start position:0% +three okay nothing join that and there's + + + align:start position:0% +three okay nothing join that and there's +some leaves as + + align:start position:0% +some leaves as + + + align:start position:0% +some leaves as +usual now if you look at maybe I'm going + + align:start position:0% +usual now if you look at maybe I'm going + + + align:start position:0% +usual now if you look at maybe I'm going +to have to draw + + align:start position:0% +to have to draw + + + align:start position:0% +to have to draw +[Music] + + align:start position:0% + + + + align:start position:0% + +this heard that sound + + align:start position:0% +this heard that sound + + + align:start position:0% +this heard that sound +before so I'm merging these nodes + + align:start position:0% +before so I'm merging these nodes + + + align:start position:0% +before so I'm merging these nodes +together and I'm merging all of these + + align:start position:0% +together and I'm merging all of these + + + align:start position:0% +together and I'm merging all of these +nodes together because each of these red + + align:start position:0% +nodes together because each of these red + + + align:start position:0% +nodes together because each of these red +nodes merges into that black node and + + align:start position:0% +nodes merges into that black node and + + + align:start position:0% +nodes merges into that black node and +I'm merging these two no no together so + + align:start position:0% +I'm merging these two no no together so + + + align:start position:0% +I'm merging these two no no together so +I'm putting this red node into that + + align:start position:0% +I'm putting this red node into that + + + align:start position:0% +I'm putting this red node into that +black node so now you can see from the + + align:start position:0% +black node so now you can see from the + + + align:start position:0% +black node so now you can see from the +root which is now + + align:start position:0% +root which is now + + + align:start position:0% +root which is now +7/18 there are three children hanging + + align:start position:0% +7/18 there are three children hanging + + + align:start position:0% +7/18 there are three children hanging +off okay so in that picture I'd like to + + align:start position:0% +off okay so in that picture I'd like to + + + align:start position:0% +off okay so in that picture I'd like to +draw that + + align:start position:0% +draw that + + + align:start position:0% +draw that +fact assuming I can get this board back + + align:start position:0% +fact assuming I can get this board back + + + align:start position:0% +fact assuming I can get this board back +down + + align:start position:0% +down + + + align:start position:0% +down +good + + align:start position:0% +good + + + align:start position:0% +good +so between 7 and 18 I have this + + align:start position:0% +so between 7 and 18 I have this + + + align:start position:0% +so between 7 and 18 I have this +conglomerate node uh 8 10 + + align:start position:0% +conglomerate node uh 8 10 + + + align:start position:0% +conglomerate node uh 8 10 +11 and there are four leaves hanging off + + align:start position:0% +11 and there are four leaves hanging off + + + align:start position:0% +11 and there are four leaves hanging off +of that + + align:start position:0% + + + + align:start position:0% + +note and off to the right after 18 I + + align:start position:0% +note and off to the right after 18 I + + + align:start position:0% +note and off to the right after 18 I +have a conglomerate node + + align:start position:0% + + + + align:start position:0% + +2226 and there are three leaves hanging + + align:start position:0% +2226 and there are three leaves hanging + + + align:start position:0% +2226 and there are three leaves hanging +off of + + align:start position:0% + + + + align:start position:0% + +there + + align:start position:0% +there + + + align:start position:0% +there +okay kind of a weird tree because we we + + align:start position:0% +okay kind of a weird tree because we we + + + align:start position:0% +okay kind of a weird tree because we we +dealt mainly with binary trees so far + + align:start position:0% +dealt mainly with binary trees so far + + + align:start position:0% +dealt mainly with binary trees so far +but this is a foreshadowing of what will + + align:start position:0% +but this is a foreshadowing of what will + + + align:start position:0% +but this is a foreshadowing of what will +come on Friday this is something called + + align:start position:0% +come on Friday this is something called + + + align:start position:0% +come on Friday this is something called +A 234 + + align:start position:0% + + + + align:start position:0% + +tree and he guesses why it's called A + + align:start position:0% +tree and he guesses why it's called A + + + align:start position:0% +tree and he guesses why it's called A + + align:start position:0% + + + + align:start position:0% + +tree you can have two three or four kids + + align:start position:0% +tree you can have two three or four kids + + + align:start position:0% +tree you can have two three or four kids +every node can have two three or four + + align:start position:0% +every node can have two three or four + + + align:start position:0% +every node can have two three or four +kids yeah except the leaves they have + + align:start position:0% +kids yeah except the leaves they have + + + align:start position:0% +kids yeah except the leaves they have +zero okay there's another nice property + + align:start position:0% +zero okay there's another nice property + + + align:start position:0% +zero okay there's another nice property +of two three four + + align:start position:0% +of two three four + + + align:start position:0% +of two three four +trees maybe hinted to that so there's + + align:start position:0% +trees maybe hinted to that so there's + + + align:start position:0% +trees maybe hinted to that so there's +really no control over whether you have + + align:start position:0% +really no control over whether you have + + + align:start position:0% +really no control over whether you have +uh two children or three children or + + align:start position:0% +uh two children or three children or + + + align:start position:0% +uh two children or three children or +four children but there's another nice + + align:start position:0% + + + + align:start position:0% + +property + + align:start position:0% +property + + + align:start position:0% +property +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +bottom all of your children have the + + align:start position:0% +bottom all of your children have the + + + align:start position:0% +bottom all of your children have the +same depth all of the all of the leaves + + align:start position:0% +same depth all of the all of the leaves + + + align:start position:0% +same depth all of the all of the leaves +have the same depth exactly all of these + + align:start position:0% +have the same depth exactly all of these + + + align:start position:0% +have the same depth exactly all of these +guys have the same depth in the tree why + + align:start position:0% +guys have the same depth in the tree why + + + align:start position:0% +guys have the same depth in the tree why +is that because of property + + align:start position:0% +is that because of property + + + align:start position:0% +is that because of property +four okay un Friday you'll see just how + + align:start position:0% +four okay un Friday you'll see just how + + + align:start position:0% +four okay un Friday you'll see just how +to maintain that property but out of + + align:start position:0% +to maintain that property but out of + + + align:start position:0% +to maintain that property but out of +this transformation we get that all of + + align:start position:0% +this transformation we get that all of + + + align:start position:0% +this transformation we get that all of +the leaves have the same depth because + + align:start position:0% +the leaves have the same depth because + + + align:start position:0% +the leaves have the same depth because +their depth now or let's say their + + align:start position:0% +their depth now or let's say their + + + align:start position:0% +their depth now or let's say their +height in the tree is their black height + + align:start position:0% +height in the tree is their black height + + + align:start position:0% +height in the tree is their black height +the the depth of these leaves will be + + align:start position:0% +the the depth of these leaves will be + + + align:start position:0% +the the depth of these leaves will be +the black height of the + + align:start position:0% +the black height of the + + + align:start position:0% +the black height of the +root okay because we sort we're erasing + + align:start position:0% +root okay because we sort we're erasing + + + align:start position:0% +root okay because we sort we're erasing +all the red nodes and we said if we look + + align:start position:0% +all the red nodes and we said if we look + + + align:start position:0% +all the red nodes and we said if we look +at a path and we ignore all the red + + align:start position:0% +at a path and we ignore all the red + + + align:start position:0% +at a path and we ignore all the red +nodes then the number of black nodes + + align:start position:0% +nodes then the number of black nodes + + + align:start position:0% +nodes then the number of black nodes +along that path is the same now we're + + align:start position:0% +along that path is the same now we're + + + align:start position:0% +along that path is the same now we're +basically just leaving all the black + + align:start position:0% +basically just leaving all the black + + + align:start position:0% +basically just leaving all the black +nodes and so along all these paths we + + align:start position:0% +nodes and so along all these paths we + + + align:start position:0% +nodes and so along all these paths we +have the same number of black nodes and + + align:start position:0% +have the same number of black nodes and + + + align:start position:0% +have the same number of black nodes and +therefore every leaf will have the same + + align:start position:0% +therefore every leaf will have the same + + + align:start position:0% +therefore every leaf will have the same +depth let me write down some of these + + align:start position:0% +depth let me write down some of these + + + align:start position:0% +depth let me write down some of these +properties so + + align:start position:0% +properties so + + + align:start position:0% +properties so +every internal + + align:start position:0% + + + + align:start position:0% + +node has between two and four + + align:start position:0% + + + + align:start position:0% + +children and + + align:start position:0% +children and + + + align:start position:0% +children and +and every leaf has the same + + align:start position:0% + + + + align:start position:0% + +depth + + align:start position:0% +depth + + + align:start position:0% +depth +namely the black height of the + + align:start position:0% + + + + align:start position:0% + +root this is by property four + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so this is telling us a lot so + + align:start position:0% +so this is telling us a lot so + + + align:start position:0% +so this is telling us a lot so +essentially what this transformation is + + align:start position:0% +essentially what this transformation is + + + align:start position:0% +essentially what this transformation is +doing is ignoring the red nodes and then + + align:start position:0% +doing is ignoring the red nodes and then + + + align:start position:0% +doing is ignoring the red nodes and then +if you just focus on the black nodes + + align:start position:0% +if you just focus on the black nodes + + + align:start position:0% +if you just focus on the black nodes +height equals black height and then + + align:start position:0% +height equals black height and then + + + align:start position:0% +height equals black height and then +black height is telling us that all the + + align:start position:0% +black height is telling us that all the + + + align:start position:0% +black height is telling us that all the +root to leaf paths have the same length + + align:start position:0% +root to leaf paths have the same length + + + align:start position:0% +root to leaf paths have the same length +therefore all these nodes are at the + + align:start position:0% +therefore all these nodes are at the + + + align:start position:0% +therefore all these nodes are at the +same + + align:start position:0% +same + + + align:start position:0% +same +level having leaves at the same level is + + align:start position:0% +level having leaves at the same level is + + + align:start position:0% +level having leaves at the same level is +a good thing because it means your tree + + align:start position:0% +a good thing because it means your tree + + + align:start position:0% +a good thing because it means your tree +is pretty much balanced if you have a + + align:start position:0% +is pretty much balanced if you have a + + + align:start position:0% +is pretty much balanced if you have a +tree where all the nodes are branching + + align:start position:0% +tree where all the nodes are branching + + + align:start position:0% +tree where all the nodes are branching +uh so they all have at least two + + align:start position:0% +uh so they all have at least two + + + align:start position:0% +uh so they all have at least two +children and all the leaves are at the + + align:start position:0% +children and all the leaves are at the + + + align:start position:0% +children and all the leaves are at the +same level that's pretty balanced okay + + align:start position:0% +same level that's pretty balanced okay + + + align:start position:0% +same level that's pretty balanced okay +we'll prove some form of that + + align:start position:0% +we'll prove some form of that + + + align:start position:0% +we'll prove some form of that +now uh I'm going to call the height of + + align:start position:0% +now uh I'm going to call the height of + + + align:start position:0% +now uh I'm going to call the height of +this tree H + + align:start position:0% +this tree H + + + align:start position:0% +this tree H +Prime the height of the original tree is + + align:start position:0% +Prime the height of the original tree is + + + align:start position:0% +Prime the height of the original tree is +H that's what we want to bound + + align:start position:0% +H that's what we want to bound + + + align:start position:0% +H that's what we want to bound +here so the first thing is to bound H + + align:start position:0% +here so the first thing is to bound H + + + align:start position:0% +here so the first thing is to bound H +Prime and then we want to relate H and H + + align:start position:0% +Prime and then we want to relate H and H + + + align:start position:0% +Prime and then we want to relate H and H +Prime + + align:start position:0% + + + + align:start position:0% + +okay so first question is how many + + align:start position:0% +okay so first question is how many + + + align:start position:0% +okay so first question is how many +leaves are there in this tree and it + + align:start position:0% +leaves are there in this tree and it + + + align:start position:0% +leaves are there in this tree and it +doesn't really matter which tree I'm + + align:start position:0% +doesn't really matter which tree I'm + + + align:start position:0% +doesn't really matter which tree I'm +looking at because I didn't do anything + + align:start position:0% +looking at because I didn't do anything + + + align:start position:0% +looking at because I didn't do anything +to the leaves all the leaves are black + + align:start position:0% +to the leaves all the leaves are black + + + align:start position:0% +to the leaves all the leaves are black +so the leaves didn't change how many + + align:start position:0% +so the leaves didn't change how many + + + align:start position:0% +so the leaves didn't change how many +leaves are there in this tree and + + align:start position:0% +leaves are there in this tree and + + + align:start position:0% +leaves are there in this tree and +therefore in this + + align:start position:0% +therefore in this + + + align:start position:0% +therefore in this +tree sorry nine nine indeed there are + + align:start position:0% +tree sorry nine nine indeed there are + + + align:start position:0% +tree sorry nine nine indeed there are +nine but I meant in general sorry this + + align:start position:0% +nine but I meant in general sorry this + + + align:start position:0% +nine but I meant in general sorry this +example there are nine how many keys are + + align:start position:0% +example there are nine how many keys are + + + align:start position:0% +example there are nine how many keys are +there eight so in + + align:start position:0% +there eight so in + + + align:start position:0% +there eight so in +general how do you write nine as a + + align:start position:0% +general how do you write nine as a + + + align:start position:0% +general how do you write nine as a +function of + + align:start position:0% + + + + align:start position:0% + +eight for large values of nine or + + align:start position:0% + + + + align:start position:0% + +eight sorry plus one plus one good + + align:start position:0% +eight sorry plus one plus one good + + + align:start position:0% +eight sorry plus one plus one good +correct answer by + + align:start position:0% +correct answer by + + + align:start position:0% +correct answer by +guessing n + one okay why is it n+1 + + align:start position:0% +guessing n + one okay why is it n+1 + + + align:start position:0% +guessing n + one okay why is it n+1 +because whenever we have let's look at + + align:start position:0% +because whenever we have let's look at + + + align:start position:0% +because whenever we have let's look at +the binary tree case where we sort of + + align:start position:0% +the binary tree case where we sort of + + + align:start position:0% +the binary tree case where we sort of +understand what's going + + align:start position:0% +understand what's going + + + align:start position:0% +understand what's going +on wherever you have a a key there are + + align:start position:0% +on wherever you have a a key there are + + + align:start position:0% +on wherever you have a a key there are +two + + align:start position:0% +two + + + align:start position:0% +two +branches and that's not a very good + + align:start position:0% +branches and that's not a very good + + + align:start position:0% +branches and that's not a very good +argument okay but we have what what is + + align:start position:0% +argument okay but we have what what is + + + align:start position:0% +argument okay but we have what what is +here called a branching binary tree + + align:start position:0% +here called a branching binary tree + + + align:start position:0% +here called a branching binary tree +every internal node has exactly two + + align:start position:0% +every internal node has exactly two + + + align:start position:0% +every internal node has exactly two +children and we're counting the number + + align:start position:0% +children and we're counting the number + + + align:start position:0% +children and we're counting the number +of leaves that you get from that process + + align:start position:0% +of leaves that you get from that process + + + align:start position:0% +of leaves that you get from that process +in terms of the number of internal nodes + + align:start position:0% +in terms of the number of internal nodes + + + align:start position:0% +in terms of the number of internal nodes +the number of leaves in a tree a + + align:start position:0% +the number of leaves in a tree a + + + align:start position:0% +the number of leaves in a tree a +branching tree is always one plus the + + align:start position:0% +branching tree is always one plus the + + + align:start position:0% +branching tree is always one plus the +number of internal nodes you should know + + align:start position:0% +number of internal nodes you should know + + + align:start position:0% +number of internal nodes you should know +that you can prove it by + + align:start position:0% +that you can prove it by + + + align:start position:0% +that you can prove it by +induction okay so the number of leaves + + align:start position:0% +induction okay so the number of leaves + + + align:start position:0% +induction okay so the number of leaves +is n plus one it doesn't hold if you + + align:start position:0% +is n plus one it doesn't hold if you + + + align:start position:0% +is n plus one it doesn't hold if you +have a single child holds if every + + align:start position:0% +have a single child holds if every + + + align:start position:0% +have a single child holds if every +internal node + + align:start position:0% +internal node + + + align:start position:0% +internal node +has uh branching factor of + + align:start position:0% + + + + align:start position:0% + +two okay this is in either + + align:start position:0% + + + + align:start position:0% + +tree and now we want to pull out some + + align:start position:0% +tree and now we want to pull out some + + + align:start position:0% +tree and now we want to pull out some +relation between the number of leaves + + align:start position:0% +relation between the number of leaves + + + align:start position:0% +relation between the number of leaves +and the height of a + + align:start position:0% +and the height of a + + + align:start position:0% +and the height of a +tree so what's a good relation to use + + align:start position:0% +tree so what's a good relation to use + + + align:start position:0% +tree so what's a good relation to use +here we know exactly how many leaves + + align:start position:0% +here we know exactly how many leaves + + + align:start position:0% +here we know exactly how many leaves +there are that will somehow connect us + + align:start position:0% +there are that will somehow connect us + + + align:start position:0% +there are that will somehow connect us +to n what we care about is the height + + align:start position:0% +to n what we care about is the height + + + align:start position:0% +to n what we care about is the height +and let's look at the height of this + + align:start position:0% + + + + align:start position:0% + +tree so if I have a 2 three4 tree of + + align:start position:0% +tree so if I have a 2 three4 tree of + + + align:start position:0% +tree so if I have a 2 three4 tree of +height H Prime how many leaves could it + + align:start position:0% +height H Prime how many leaves could it + + + align:start position:0% +height H Prime how many leaves could it +have what's the minimum and maximum + + align:start position:0% +have what's the minimum and maximum + + + align:start position:0% +have what's the minimum and maximum +number of leaves it could + + align:start position:0% +number of leaves it could + + + align:start position:0% +number of leaves it could +have 2 to the H to four to the H or H + + align:start position:0% +have 2 to the H to four to the H or H + + + align:start position:0% +have 2 to the H to four to the H or H +Prime + + align:start position:0% +Prime + + + align:start position:0% +Prime +so we also know in the 234 + + align:start position:0% + + + + align:start position:0% + +tree the number of + + align:start position:0% +tree the number of + + + align:start position:0% +tree the number of +leaves has to be between four to the H + + align:start position:0% +leaves has to be between four to the H + + + align:start position:0% +leaves has to be between four to the H +Prime because at most I could Branch + + align:start position:0% +Prime because at most I could Branch + + + align:start position:0% +Prime because at most I could Branch +four ways in each node and it's at least + + align:start position:0% +four ways in each node and it's at least + + + align:start position:0% +four ways in each node and it's at least +2 to the H Prime because I know that + + align:start position:0% +2 to the H Prime because I know that + + + align:start position:0% +2 to the H Prime because I know that +every node branches at least two ways + + align:start position:0% +every node branches at least two ways + + + align:start position:0% +every node branches at least two ways +that's + + align:start position:0% +that's + + + align:start position:0% +that's +key so I only care about one of these I + + align:start position:0% +key so I only care about one of these I + + + align:start position:0% +key so I only care about one of these I +think this one + + align:start position:0% +think this one + + + align:start position:0% +think this one +so I get that 2 the H Prime is at most n + + align:start position:0% +so I get that 2 the H Prime is at most n + + + align:start position:0% +so I get that 2 the H Prime is at most n ++ 1 because the number of leaves is n+1 + + align:start position:0% ++ 1 because the number of leaves is n+1 + + + align:start position:0% ++ 1 because the number of leaves is n+1 +we know that exactly so we rewrite we + + align:start position:0% +we know that exactly so we rewrite we + + + align:start position:0% +we know that exactly so we rewrite we +take logs of both sides this says H1 is + + align:start position:0% +take logs of both sides this says H1 is + + + align:start position:0% +take logs of both sides this says H1 is +at most log of n + + + align:start position:0% +at most log of n + + + + align:start position:0% +at most log of n + +one so we have a nice balanced tree this + + align:start position:0% +one so we have a nice balanced tree this + + + align:start position:0% +one so we have a nice balanced tree this +should be intuitive if I had every node + + align:start position:0% +should be intuitive if I had every node + + + align:start position:0% +should be intuitive if I had every node +branching two ways and all the leaves at + + align:start position:0% +branching two ways and all the leaves at + + + align:start position:0% +branching two ways and all the leaves at +the same level that's a perfect tree + + align:start position:0% +the same level that's a perfect tree + + + align:start position:0% +the same level that's a perfect tree +should be exact + + align:start position:0% +should be exact + + + align:start position:0% +should be exact +log base 2 of n plus1 it turns out not + + align:start position:0% +log base 2 of n plus1 it turns out not + + + align:start position:0% +log base 2 of n plus1 it turns out not +quite n that should be the height of the + + align:start position:0% +quite n that should be the height of the + + + align:start position:0% +quite n that should be the height of the +tree here I might have even more + + align:start position:0% +tree here I might have even more + + + align:start position:0% +tree here I might have even more +branching which is making things even + + align:start position:0% +branching which is making things even + + + align:start position:0% +branching which is making things even +shallower in some sense so I get more + + align:start position:0% +shallower in some sense so I get more + + + align:start position:0% +shallower in some sense so I get more +leaves out of the same height but that's + + align:start position:0% +leaves out of the same height but that's + + + align:start position:0% +leaves out of the same height but that's +only better for me that will only + + align:start position:0% +only better for me that will only + + + align:start position:0% +only better for me that will only +decrease the height in terms of the + + align:start position:0% +decrease the height in terms of the + + + align:start position:0% +decrease the height in terms of the +number of leaves n plus one here was the + + align:start position:0% +number of leaves n plus one here was the + + + align:start position:0% +number of leaves n plus one here was the +the number of leaves so + + align:start position:0% +the number of leaves so + + + align:start position:0% +the number of leaves so +cool that's an easy upper bound on the + + align:start position:0% +cool that's an easy upper bound on the + + + align:start position:0% +cool that's an easy upper bound on the +height of this tree now what we really + + align:start position:0% +height of this tree now what we really + + + align:start position:0% +height of this tree now what we really +care about is the height of this tree so + + align:start position:0% +care about is the height of this tree so + + + align:start position:0% +care about is the height of this tree so +we want to relate H and H Prime any + + align:start position:0% +we want to relate H and H Prime any + + + align:start position:0% +we want to relate H and H Prime any +suggestions on how we might do + + align:start position:0% +suggestions on how we might do + + + align:start position:0% +suggestions on how we might do +that how do we know that the height of + + align:start position:0% +that how do we know that the height of + + + align:start position:0% +that how do we know that the height of +this reduced tree is not too much + + align:start position:0% +this reduced tree is not too much + + + align:start position:0% +this reduced tree is not too much +smaller than this one we know that this + + align:start position:0% +smaller than this one we know that this + + + align:start position:0% +smaller than this one we know that this +one is at most log n we want this one to + + align:start position:0% +one is at most log n we want this one to + + + align:start position:0% +one is at most log n we want this one to +be at most to log n plus + + align:start position:0% +be at most to log n plus + + + align:start position:0% +be at most to log n plus +one we know the answer we said the + + align:start position:0% +one we know the answer we said the + + + align:start position:0% +one we know the answer we said the +theorem + + align:start position:0% + + + + align:start position:0% + +sorry right so property 3 tells us that + + align:start position:0% +sorry right so property 3 tells us that + + + align:start position:0% +sorry right so property 3 tells us that +we can only have one one red node for + + align:start position:0% +we can only have one one red node for + + + align:start position:0% +we can only have one one red node for +every black one we can at most alternate + + align:start position:0% +every black one we can at most alternate + + + align:start position:0% +every black one we can at most alternate +red and black so if we look at one of + + align:start position:0% +red and black so if we look at one of + + + align:start position:0% +red and black so if we look at one of +these paths that goes from a root to the + + align:start position:0% +these paths that goes from a root to the + + + align:start position:0% +these paths that goes from a root to the +to a leaf the root to a leaf the number + + align:start position:0% +to a leaf the root to a leaf the number + + + align:start position:0% +to a leaf the root to a leaf the number +of red nodes can be at most half the + + align:start position:0% +of red nodes can be at most half the + + + align:start position:0% +of red nodes can be at most half the +length of the path and that's that's if + + align:start position:0% +length of the path and that's that's if + + + align:start position:0% +length of the path and that's that's if +we take the max overall paths that's the + + align:start position:0% +we take the max overall paths that's the + + + align:start position:0% +we take the max overall paths that's the +height of the tree so we know that H is + + align:start position:0% +height of the tree so we know that H is + + + align:start position:0% +height of the tree so we know that H is +at most 2 * H + + align:start position:0% +at most 2 * H + + + align:start position:0% +at most 2 * H +prime or maybe it's easier to think of H + + align:start position:0% +prime or maybe it's easier to think of H + + + align:start position:0% +prime or maybe it's easier to think of H +Prime is at least a half H so me I got + + align:start position:0% +Prime is at least a half H so me I got + + + align:start position:0% +Prime is at least a half H so me I got +that right uh + + align:start position:0% +that right uh + + + align:start position:0% +that right uh +because at most a half of the nodes on + + align:start position:0% +because at most a half of the nodes on + + + align:start position:0% +because at most a half of the nodes on +any root to Leaf + + align:start position:0% + + + + align:start position:0% + +path are + + align:start position:0% +path are + + + align:start position:0% +path are +red so at least half of them have to be + + align:start position:0% +red so at least half of them have to be + + + align:start position:0% +red so at least half of them have to be +black and all the black nodes are + + align:start position:0% +black and all the black nodes are + + + align:start position:0% +black and all the black nodes are +captured in this picture because we only + + align:start position:0% +captured in this picture because we only + + + align:start position:0% +captured in this picture because we only +threw away the red nodes so we have this + + align:start position:0% +threw away the red nodes so we have this + + + align:start position:0% +threw away the red nodes so we have this +relation and therefore H is at most 2 * + + align:start position:0% +relation and therefore H is at most 2 * + + + align:start position:0% +relation and therefore H is at most 2 * +log n + + align:start position:0% + + + + align:start position:0% + ++1 okay pretty easy but have to remember + + align:start position:0% ++1 okay pretty easy but have to remember + + + align:start position:0% ++1 okay pretty easy but have to remember +this tree has to be balanced and that + + align:start position:0% +this tree has to be balanced and that + + + align:start position:0% +this tree has to be balanced and that +they're not too far away from each other + + align:start position:0% +they're not too far away from each other + + + align:start position:0% +they're not too far away from each other +okay so in Friday Friday's recitation + + align:start position:0% +okay so in Friday Friday's recitation + + + align:start position:0% +okay so in Friday Friday's recitation +you'll see how to manipulate trees of + + align:start position:0% +you'll see how to manipulate trees of + + + align:start position:0% +you'll see how to manipulate trees of +this form there's a cool way to do it + + align:start position:0% +this form there's a cool way to do it + + + align:start position:0% +this form there's a cool way to do it +that's 234 trees today we're going to + + align:start position:0% +that's 234 trees today we're going to + + + align:start position:0% +that's 234 trees today we're going to +see how to manipulate trees in this form + + align:start position:0% +see how to manipulate trees in this form + + + align:start position:0% +see how to manipulate trees in this form +as red black trees and you'll see + + align:start position:0% +as red black trees and you'll see + + + align:start position:0% +as red black trees and you'll see +today's lecture and you'll see Friday's + + align:start position:0% +today's lecture and you'll see Friday's + + + align:start position:0% +today's lecture and you'll see Friday's +recitation and they won't really seem to + + align:start position:0% +recitation and they won't really seem to + + + align:start position:0% +recitation and they won't really seem to +relate at all but they're the same just + + align:start position:0% +relate at all but they're the same just + + + align:start position:0% +relate at all but they're the same just +a bit + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +hidden + + align:start position:0% + + + + align:start position:0% + +okay so this is good news we now know + + align:start position:0% +okay so this is good news we now know + + + align:start position:0% +okay so this is good news we now know +that all red black trees are balanced so + + align:start position:0% +that all red black trees are balanced so + + + align:start position:0% +that all red black trees are balanced so +as long as we can make sure that our + + align:start position:0% +as long as we can make sure that our + + + align:start position:0% +as long as we can make sure that our +tree stays a red black + + align:start position:0% +tree stays a red black + + + align:start position:0% +tree stays a red black +tree uh we'll be okay + + align:start position:0% +tree uh we'll be okay + + + align:start position:0% +tree uh we'll be okay +will be okay in the sense that the + + align:start position:0% +will be okay in the sense that the + + + align:start position:0% +will be okay in the sense that the +height is always log n and + + align:start position:0% +height is always log n and + + + align:start position:0% +height is always log n and +therefore uh + + align:start position:0% + + + + align:start position:0% + +queries in a red black tree so queries + + align:start position:0% +queries in a red black tree so queries + + + align:start position:0% +queries in a red black tree so queries +are things like search find a given key + + align:start position:0% +are things like search find a given key + + + align:start position:0% +are things like search find a given key +uh find the minimum find the + + align:start position:0% +uh find the minimum find the + + + align:start position:0% +uh find the minimum find the +maximum find the + + align:start position:0% +maximum find the + + + align:start position:0% +maximum find the +successor find the predecessor these are + + align:start position:0% +successor find the predecessor these are + + + align:start position:0% +successor find the predecessor these are +all queries that we know how to support + + align:start position:0% +all queries that we know how to support + + + align:start position:0% +all queries that we know how to support +in a in a binary search tree + + align:start position:0% +in a in a binary search tree + + + align:start position:0% +in a in a binary search tree +and we know how to do them in order + + align:start position:0% +and we know how to do them in order + + + align:start position:0% +and we know how to do them in order +height + + align:start position:0% + + + + align:start position:0% + +time and the height here is log n so we + + align:start position:0% +time and the height here is log n so we + + + align:start position:0% +time and the height here is log n so we +know that all of these operations take + + align:start position:0% +know that all of these operations take + + + align:start position:0% +know that all of these operations take +order log + + align:start position:0% + + + + align:start position:0% + +n in a red black + + align:start position:0% + + + + align:start position:0% + +tree okay + + align:start position:0% + + + + align:start position:0% + +so queries are easy we're done with + + align:start position:0% +so queries are easy we're done with + + + align:start position:0% +so queries are easy we're done with +queries just be just from balance not a + + align:start position:0% +queries just be just from balance not a + + + align:start position:0% +queries just be just from balance not a +surprise we know that balance is good + + align:start position:0% +surprise we know that balance is good + + + align:start position:0% +surprise we know that balance is good +the hard part for us will be to do + + align:start position:0% +the hard part for us will be to do + + + align:start position:0% +the hard part for us will be to do +updates + + align:start position:0% + + + + align:start position:0% + +and in this context updates means insert + + align:start position:0% +and in this context updates means insert + + + align:start position:0% +and in this context updates means insert +and + + align:start position:0% + + + + align:start position:0% + +delete in general in a data structure we + + align:start position:0% +delete in general in a data structure we + + + align:start position:0% +delete in general in a data structure we +talk about queries that which ask ask + + align:start position:0% +talk about queries that which ask ask + + + align:start position:0% +talk about queries that which ask ask +questions about the data in the + + align:start position:0% +questions about the data in the + + + align:start position:0% +questions about the data in the +structure and updates which modify the + + align:start position:0% +structure and updates which modify the + + + align:start position:0% +structure and updates which modify the +data in the structure and most of the + + align:start position:0% +data in the structure and most of the + + + align:start position:0% +data in the structure and most of the +time here we're always thinking about + + align:start position:0% +time here we're always thinking about + + + align:start position:0% +time here we're always thinking about +Dynamic sets so you can change the + + align:start position:0% +Dynamic sets so you can change the + + + align:start position:0% +Dynamic sets so you can change the +dynamic set by adding or deleting an + + align:start position:0% +dynamic set by adding or deleting an + + + align:start position:0% +dynamic set by adding or deleting an +element you can ask all sorts of + + align:start position:0% +element you can ask all sorts of + + + align:start position:0% +element you can ask all sorts of +questions in priority cues there were + + align:start position:0% +questions in priority cues there were + + + align:start position:0% +questions in priority cues there were +other updates like delete men + + align:start position:0% +other updates like delete men + + + align:start position:0% +other updates like delete men +here we have find men but no we could + + align:start position:0% +here we have find men but no we could + + + align:start position:0% +here we have find men but no we could +then delete it okay but typically these + + align:start position:0% +then delete it okay but typically these + + + align:start position:0% +then delete it okay but typically these +are the operations we care about and + + align:start position:0% +are the operations we care about and + + + align:start position:0% +are the operations we care about and +we'll talk about updates to include both + + align:start position:0% +we'll talk about updates to include both + + + align:start position:0% +we'll talk about updates to include both +of these and queries to include all of + + align:start position:0% +of these and queries to include all of + + + align:start position:0% +of these and queries to include all of +these or whatever happens to be relevant + + align:start position:0% +these or whatever happens to be relevant + + + align:start position:0% +these or whatever happens to be relevant +in problem sets especially you'll see + + align:start position:0% +in problem sets especially you'll see + + + align:start position:0% +in problem sets especially you'll see +all sorts of different queries that you + + align:start position:0% +all sorts of different queries that you + + + align:start position:0% +all sorts of different queries that you +can + + align:start position:0% + + + + align:start position:0% + +support okay so how do we support + + align:start position:0% +support okay so how do we support + + + align:start position:0% +support okay so how do we support +updates well we have binary search tree + + align:start position:0% +updates well we have binary search tree + + + align:start position:0% +updates well we have binary search tree +insert which we call tree insert we have + + align:start position:0% +insert which we call tree insert we have + + + align:start position:0% +insert which we call tree insert we have +we have binary search tree delete tree + + align:start position:0% +we have binary search tree delete tree + + + align:start position:0% +we have binary search tree delete tree +delete uh they will preserve the binary + + align:start position:0% +delete uh they will preserve the binary + + + align:start position:0% +delete uh they will preserve the binary +search tree property but we know they + + align:start position:0% +search tree property but we know they + + + align:start position:0% +search tree property but we know they +don't necessarily preserve balance you + + align:start position:0% +don't necessarily preserve balance you + + + align:start position:0% +don't necessarily preserve balance you +can insert a bunch of nodes just keep + + align:start position:0% +can insert a bunch of nodes just keep + + + align:start position:0% +can insert a bunch of nodes just keep +adding new minimum elements and you'll + + align:start position:0% +adding new minimum elements and you'll + + + align:start position:0% +adding new minimum elements and you'll +get a really long path off the end so + + align:start position:0% +get a really long path off the end so + + + align:start position:0% +get a really long path off the end so +presumably they do not preserve the red + + align:start position:0% +presumably they do not preserve the red + + + align:start position:0% +presumably they do not preserve the red +black properties because we know red + + align:start position:0% +black properties because we know red + + + align:start position:0% +black properties because we know red +black implies balanced in particular + + align:start position:0% +black implies balanced in particular + + + align:start position:0% +black implies balanced in particular +they won't satisfy property one which + + align:start position:0% +they won't satisfy property one which + + + align:start position:0% +they won't satisfy property one which +I've erased which is every node is red + + align:start position:0% +I've erased which is every node is red + + + align:start position:0% +I've erased which is every node is red +or black it'll add a node and not assign + + align:start position:0% +or black it'll add a node and not assign + + + align:start position:0% +or black it'll add a node and not assign +it a color so we've got to assign it a + + align:start position:0% +it a color so we've got to assign it a + + + align:start position:0% +it a color so we've got to assign it a +color + + align:start position:0% +color + + + align:start position:0% +color +and as soon as we do that we'll probably + + align:start position:0% +and as soon as we do that we'll probably + + + align:start position:0% +and as soon as we do that we'll probably +violate some other property and then we + + align:start position:0% +violate some other property and then we + + + align:start position:0% +violate some other property and then we +have to fix that property and so on so + + align:start position:0% +have to fix that property and so on so + + + align:start position:0% +have to fix that property and so on so +it's a bit tricky but you play around + + align:start position:0% +it's a bit tricky but you play around + + + align:start position:0% +it's a bit tricky but you play around +with it and it's not too + + align:start position:0% +with it and it's not too + + + align:start position:0% +with it and it's not too +hard okay + + align:start position:0% +hard okay + + + align:start position:0% +hard okay +so updates must modify the + + align:start position:0% + + + + align:start position:0% + +tree and they're going to do it in to + + align:start position:0% +tree and they're going to do it in to + + + align:start position:0% +tree and they're going to do it in to +preserve the red black properties + + align:start position:0% +preserve the red black properties + + + align:start position:0% +preserve the red black properties +they're going to do it in three + + align:start position:0% +they're going to do it in three + + + align:start position:0% +they're going to do it in three +different kinds of + + align:start position:0% +different kinds of + + + align:start position:0% +different kinds of +modifications the first thing we will + + align:start position:0% +modifications the first thing we will + + + align:start position:0% +modifications the first thing we will +indeed do is just use the BST operation + + align:start position:0% +indeed do is just use the BST operation + + + align:start position:0% +indeed do is just use the BST operation +tree insert or tree delete that's + + align:start position:0% +tree insert or tree delete that's + + + align:start position:0% +tree insert or tree delete that's +something we know how to do let's just + + align:start position:0% +something we know how to do let's just + + + align:start position:0% +something we know how to do let's just +do + + align:start position:0% +do + + + align:start position:0% +do +it we're going to have to change the + + align:start position:0% +it we're going to have to change the + + + align:start position:0% +it we're going to have to change the +colors of some of the nodes in + + align:start position:0% +colors of some of the nodes in + + + align:start position:0% +colors of some of the nodes in +particular the one that we insert better + + align:start position:0% +particular the one that we insert better + + + align:start position:0% +particular the one that we insert better +be colored somehow and in general if we + + align:start position:0% +be colored somehow and in general if we + + + align:start position:0% +be colored somehow and in general if we +just rip out a node we're going to have + + align:start position:0% +just rip out a node we're going to have + + + align:start position:0% +just rip out a node we're going to have +to recolor + + align:start position:0% +to recolor + + + align:start position:0% +to recolor +it recolor some uh nearby nodes + + align:start position:0% +it recolor some uh nearby nodes + + + align:start position:0% +it recolor some uh nearby nodes +there's one other kind of operation + + align:start position:0% +there's one other kind of operation + + + align:start position:0% +there's one other kind of operation +we're going to do so recoloring just + + align:start position:0% +we're going to do so recoloring just + + + align:start position:0% +we're going to do so recoloring just +means set to red or + + align:start position:0% +means set to red or + + + align:start position:0% +means set to red or +black the other thing you might do is + + align:start position:0% +black the other thing you might do is + + + align:start position:0% +black the other thing you might do is +rearrange the tree change the pointers + + align:start position:0% +rearrange the tree change the pointers + + + align:start position:0% +rearrange the tree change the pointers +change the links from one node to + + align:start position:0% +change the links from one node to + + + align:start position:0% +change the links from one node to +another and we're going to do that in a + + align:start position:0% +another and we're going to do that in a + + + align:start position:0% +another and we're going to do that in a +very structured way and this is one of + + align:start position:0% +very structured way and this is one of + + + align:start position:0% +very structured way and this is one of +the main reasons that uh red black trees + + align:start position:0% +the main reasons that uh red black trees + + + align:start position:0% +the main reasons that uh red black trees +are interesting the kinds of changes + + align:start position:0% +are interesting the kinds of changes + + + align:start position:0% +are interesting the kinds of changes +they make are very simple and they also + + align:start position:0% +they make are very simple and they also + + + align:start position:0% +they make are very simple and they also +don't make very many of them so they're + + align:start position:0% +don't make very many of them so they're + + + align:start position:0% +don't make very many of them so they're +called rotations + + align:start position:0% +called rotations + + + align:start position:0% +called rotations +so here's a + + align:start position:0% + + + + align:start position:0% + +rotation okay this is a way of gener + + align:start position:0% +rotation okay this is a way of gener + + + align:start position:0% +rotation okay this is a way of gener +drawing a generic part of the a tree we + + align:start position:0% +drawing a generic part of the a tree we + + + align:start position:0% +drawing a generic part of the a tree we +have two nodes A and B there's some sub + + align:start position:0% +have two nodes A and B there's some sub + + + align:start position:0% +have two nodes A and B there's some sub +trees hanging off which we draw as + + align:start position:0% +trees hanging off which we draw as + + + align:start position:0% +trees hanging off which we draw as +triangles we don't know how big they are + + align:start position:0% +triangles we don't know how big they are + + + align:start position:0% +triangles we don't know how big they are +we know they better all have the same + + align:start position:0% +we know they better all have the same + + + align:start position:0% +we know they better all have the same +black height if it's red black tree but + + align:start position:0% +black height if it's red black tree but + + + align:start position:0% +black height if it's red black tree but +in general it just looks like this + + align:start position:0% +in general it just looks like this + + + align:start position:0% +in general it just looks like this +there's some parent and there's some + + align:start position:0% +there's some parent and there's some + + + align:start position:0% +there's some parent and there's some +rest of the tree out here which we don't + + align:start position:0% +rest of the tree out here which we don't + + + align:start position:0% +rest of the tree out here which we don't +draw I'll give these sub trees names + + align:start position:0% +draw I'll give these sub trees names + + + align:start position:0% +draw I'll give these sub trees names +Greek names Alpha Beta + + align:start position:0% +Greek names Alpha Beta + + + align:start position:0% +Greek names Alpha Beta +gamma and I'll Define the Operation + + align:start position:0% +gamma and I'll Define the Operation + + + align:start position:0% +gamma and I'll Define the Operation +right + + align:start position:0% +right + + + align:start position:0% +right +rotate of + + align:start position:0% +rotate of + + + align:start position:0% +rotate of +B so in general if I have a node B I + + align:start position:0% +B so in general if I have a node B I + + + align:start position:0% +B so in general if I have a node B I +look at it and I want to do a right + + align:start position:0% +look at it and I want to do a right + + + align:start position:0% +look at it and I want to do a right +rotation I look at its left child and + + align:start position:0% +rotation I look at its left child and + + + align:start position:0% +rotation I look at its left child and +draw this picture all the sub trees of + + align:start position:0% +draw this picture all the sub trees of + + + align:start position:0% +draw this picture all the sub trees of +those two nodes + + align:start position:0% +those two nodes + + + align:start position:0% +those two nodes +and I create this + + align:start position:0% + + + + align:start position:0% + +tree so all I've done is turn this Edge + + align:start position:0% +tree so all I've done is turn this Edge + + + align:start position:0% +tree so all I've done is turn this Edge +90° the parent what was the parent of B + + align:start position:0% +90° the parent what was the parent of B + + + align:start position:0% +90° the parent what was the parent of B +is now the parent of a a is now the new + + align:start position:0% +is now the parent of a a is now the new + + + align:start position:0% +is now the parent of a a is now the new +parent of B the sub trees rearranged + + align:start position:0% +parent of B the sub trees rearranged + + + align:start position:0% +parent of B the sub trees rearranged +before they were both subt trees of + + align:start position:0% +before they were both subt trees of + + + align:start position:0% +before they were both subt trees of +these two are sub trees of a and Gamma + + align:start position:0% +these two are sub trees of a and Gamma + + + align:start position:0% +these two are sub trees of a and Gamma +was a sub tree of B gamma is still a + + align:start position:0% +was a sub tree of B gamma is still a + + + align:start position:0% +was a sub tree of B gamma is still a +subt tree of B and Alpha is still a subt + + align:start position:0% +subt tree of B and Alpha is still a subt + + + align:start position:0% +subt tree of B and Alpha is still a subt +tree of a but beta switched to being a + + align:start position:0% +tree of a but beta switched to being a + + + align:start position:0% +tree of a but beta switched to being a +sub tree of B okay the main thing we + + align:start position:0% +sub tree of B okay the main thing we + + + align:start position:0% +sub tree of B okay the main thing we +want to check here is that this + + align:start position:0% +want to check here is that this + + + align:start position:0% +want to check here is that this +operation + + align:start position:0% +operation + + + align:start position:0% +operation +preserves the binary search tree + + align:start position:0% + + + + align:start position:0% + +property remember the binary search tree + + align:start position:0% +property remember the binary search tree + + + align:start position:0% +property remember the binary search tree +property says that all the elements in + + align:start position:0% +property says that all the elements in + + + align:start position:0% +property says that all the elements in +the left sub tree of a node are less + + align:start position:0% +the left sub tree of a node are less + + + align:start position:0% +the left sub tree of a node are less +than or equal to the node and all the + + align:start position:0% +than or equal to the node and all the + + + align:start position:0% +than or equal to the node and all the +elements in the right sub tree are + + align:start position:0% +elements in the right sub tree are + + + align:start position:0% +elements in the right sub tree are +greater than or equal to that value so + + align:start position:0% +greater than or equal to that value so + + + align:start position:0% +greater than or equal to that value so +in particular if we take some node + + align:start position:0% +in particular if we take some node + + + align:start position:0% +in particular if we take some node +little a in Alpha little B in beta and + + align:start position:0% +little a in Alpha little B in beta and + + + align:start position:0% +little a in Alpha little B in beta and +little C in gamma then a is less than or + + align:start position:0% +little C in gamma then a is less than or + + + align:start position:0% +little C in gamma then a is less than or +equal to Capital a is less than equal to + + align:start position:0% +equal to Capital a is less than equal to + + + align:start position:0% +equal to Capital a is less than equal to +Little B is less than equal to capital B + + align:start position:0% +Little B is less than equal to capital B + + + align:start position:0% +Little B is less than equal to capital B +it's less than or equal to little + + align:start position:0% +it's less than or equal to little + + + align:start position:0% +it's less than or equal to little +C okay and that this is the condition + + align:start position:0% +C okay and that this is the condition + + + align:start position:0% +C okay and that this is the condition +condition both on the left side and on + + align:start position:0% +condition both on the left side and on + + + align:start position:0% +condition both on the left side and on +the right side CU Alpha is less is left + + align:start position:0% +the right side CU Alpha is less is left + + + align:start position:0% +the right side CU Alpha is less is left +of everything beta is in between a and b + + align:start position:0% +of everything beta is in between a and b + + + align:start position:0% +of everything beta is in between a and b +and Gamma is after B the same thing is + + align:start position:0% +and Gamma is after B the same thing is + + + align:start position:0% +and Gamma is after B the same thing is +true over here beta is still supposed to + + align:start position:0% +true over here beta is still supposed to + + + align:start position:0% +true over here beta is still supposed to +be all the nodes that come between + + align:start position:0% +be all the nodes that come between + + + align:start position:0% +be all the nodes that come between +capital A and capital B so this is this + + align:start position:0% +capital A and capital B so this is this + + + align:start position:0% +capital A and capital B so this is this +is good we can definitely do this + + align:start position:0% +is good we can definitely do this + + + align:start position:0% +is good we can definitely do this +operation still have a binary search + + align:start position:0% +operation still have a binary search + + + align:start position:0% +operation still have a binary search +tree and we're going to use rotations in + + align:start position:0% +tree and we're going to use rotations in + + + align:start position:0% +tree and we're going to use rotations in +a particularly careful way to make sure + + align:start position:0% +a particularly careful way to make sure + + + align:start position:0% +a particularly careful way to make sure +that we maintain all of these properties + + align:start position:0% +that we maintain all of these properties + + + align:start position:0% +that we maintain all of these properties +that's the hard part but rotations will + + align:start position:0% +that's the hard part but rotations will + + + align:start position:0% +that's the hard part but rotations will +be our key this was the right rotate + + align:start position:0% +be our key this was the right rotate + + + align:start position:0% +be our key this was the right rotate +operation the reverse operation is left + + align:start position:0% + + + + align:start position:0% + +rotate so this is left rotate of + + align:start position:0% +rotate so this is left rotate of + + + align:start position:0% +rotate so this is left rotate of +a in general of the two nodes that are + + align:start position:0% +a in general of the two nodes that are + + + align:start position:0% +a in general of the two nodes that are +involved we list the top one says right + + align:start position:0% +involved we list the top one says right + + + align:start position:0% +involved we list the top one says right +rotate of B will give you this left + + align:start position:0% +rotate of B will give you this left + + + align:start position:0% +rotate of B will give you this left +rotate of a will give you this so these + + align:start position:0% +rotate of a will give you this so these + + + align:start position:0% +rotate of a will give you this so these +are reversible + + align:start position:0% + + + + align:start position:0% + +operations which feels good uh the other + + align:start position:0% +operations which feels good uh the other + + + align:start position:0% +operations which feels good uh the other +thing is that they only take constant + + align:start position:0% +thing is that they only take constant + + + align:start position:0% +thing is that they only take constant +time + + align:start position:0% +time + + + align:start position:0% +time +these are constant time + + align:start position:0% +these are constant time + + + align:start position:0% +these are constant time +operations because we're only changing a + + align:start position:0% +operations because we're only changing a + + + align:start position:0% +operations because we're only changing a +constant number of pointers as long as + + align:start position:0% +constant number of pointers as long as + + + align:start position:0% +constant number of pointers as long as +you know the node B that you're + + align:start position:0% +you know the node B that you're + + + align:start position:0% +you know the node B that you're +interested in you set the left pointer + + align:start position:0% +interested in you set the left pointer + + + align:start position:0% +interested in you set the left pointer +of B to be you want it to be beta so you + + align:start position:0% +of B to be you want it to be beta so you + + + align:start position:0% +of B to be you want it to be beta so you +set left of B to be right of a and so on + + align:start position:0% +set left of B to be right of a and so on + + + align:start position:0% +set left of B to be right of a and so on +and so on you make a constant number of + + align:start position:0% +and so on you make a constant number of + + + align:start position:0% +and so on you make a constant number of +those changes you update the parents as + + align:start position:0% +those changes you update the parents as + + + align:start position:0% +those changes you update the parents as +well it's only a constant number of + + align:start position:0% +well it's only a constant number of + + + align:start position:0% +well it's only a constant number of +links that are changing so constant + + align:start position:0% +links that are changing so constant + + + align:start position:0% +links that are changing so constant +number of assignments you need to + + align:start position:0% +number of assignments you need to + + + align:start position:0% +number of assignments you need to +do okay you've probably seen rotations + + align:start position:0% +do okay you've probably seen rotations + + + align:start position:0% +do okay you've probably seen rotations +before but we're going to use + + align:start position:0% + + + + align:start position:0% + +them in a complicated + + align:start position:0% + + + + align:start position:0% + +way so let's look at how to do + + align:start position:0% + + + + align:start position:0% + +insertion we'll see it three times in + + align:start position:0% +insertion we'll see it three times in + + + align:start position:0% +insertion we'll see it three times in +some sense + + align:start position:0% + + + + align:start position:0% + +first I'll tell you the basic idea which + + align:start position:0% +first I'll tell you the basic idea which + + + align:start position:0% +first I'll tell you the basic idea which +is pretty simple mentioned some of it + + align:start position:0% +is pretty simple mentioned some of it + + + align:start position:0% +is pretty simple mentioned some of it +already then we'll do it on an example + + align:start position:0% +already then we'll do it on an example + + + align:start position:0% +already then we'll do it on an example +feel it in our bones and then we'll give + + align:start position:0% +feel it in our bones and then we'll give + + + align:start position:0% +feel it in our bones and then we'll give +the pseudo + + align:start position:0% +the pseudo + + + align:start position:0% +the pseudo +code so that you could go home and + + align:start position:0% +code so that you could go home and + + + align:start position:0% +code so that you could go home and +implement it if you + + align:start position:0% +implement it if you + + + align:start position:0% +implement it if you +wanted okay this is I should say red + + align:start position:0% +wanted okay this is I should say red + + + align:start position:0% +wanted okay this is I should say red +black insert which in the book is called + + align:start position:0% +black insert which in the book is called + + + align:start position:0% +black insert which in the book is called +RB + + align:start position:0% +RB + + + align:start position:0% +RB +insert not for root beer but for red + + align:start position:0% +insert not for root beer but for red + + + align:start position:0% +insert not for root beer but for red +black + + align:start position:0% + + + + align:start position:0% + +okay so the first thing we're going to + + align:start position:0% +okay so the first thing we're going to + + + align:start position:0% +okay so the first thing we're going to +do as I said is binary search tree + + align:start position:0% +do as I said is binary search tree + + + align:start position:0% +do as I said is binary search tree +insert that node so X now becomes a new + + align:start position:0% +insert that node so X now becomes a new + + + align:start position:0% +insert that node so X now becomes a new +Leaf we search for X wherever it's + + align:start position:0% +Leaf we search for X wherever it's + + + align:start position:0% +Leaf we search for X wherever it's +supposed to go we create a new shouldn't + + align:start position:0% +supposed to go we create a new shouldn't + + + align:start position:0% +supposed to go we create a new shouldn't +call it a leaf now it's now uh a node + + align:start position:0% +call it a leaf now it's now uh a node + + + align:start position:0% +call it a leaf now it's now uh a node +hanging off it's an internal node + + align:start position:0% +hanging off it's an internal node + + + align:start position:0% +hanging off it's an internal node +hanging off one of the original nodes + + align:start position:0% +hanging off one of the original nodes + + + align:start position:0% +hanging off one of the original nodes +maybe we added it right here it now gets + + align:start position:0% +maybe we added it right here it now gets + + + align:start position:0% +maybe we added it right here it now gets +two new leaves hanging off of + + align:start position:0% +two new leaves hanging off of + + + align:start position:0% +two new leaves hanging off of +it has no internal + + align:start position:0% +it has no internal + + + align:start position:0% +it has no internal +children and we get to pick a color for + + align:start position:0% +children and we get to pick a color for + + + align:start position:0% +children and we get to pick a color for +it and + + align:start position:0% +it and + + + align:start position:0% +it and +we will pick the color + + align:start position:0% +we will pick the color + + + align:start position:0% +we will pick the color +red okay why red we definitely have to + + align:start position:0% +red okay why red we definitely have to + + + align:start position:0% +red okay why red we definitely have to +pick one of two colors we could flip a + + align:start position:0% +pick one of two colors we could flip a + + + align:start position:0% +pick one of two colors we could flip a +coin that might work but it's going to + + align:start position:0% +coin that might work but it's going to + + + align:start position:0% +coin that might work but it's going to +make our job even Messier + + align:start position:0% +make our job even Messier + + + align:start position:0% +make our job even Messier +so we're adding a new node okay it's not + + align:start position:0% +so we're adding a new node okay it's not + + + align:start position:0% +so we're adding a new node okay it's not +a root or a leaf presumably so we don't + + align:start position:0% +a root or a leaf presumably so we don't + + + align:start position:0% +a root or a leaf presumably so we don't +really need it to be Black by property + + align:start position:0% +really need it to be Black by property + + + align:start position:0% +really need it to be Black by property +two property three every red node has a + + align:start position:0% +two property three every red node has a + + + align:start position:0% +two property three every red node has a +black parent that might be a problem so + + align:start position:0% +black parent that might be a problem so + + + align:start position:0% +black parent that might be a problem so +problem is if it's parent is + + align:start position:0% +problem is if it's parent is + + + align:start position:0% +problem is if it's parent is +red then we violate Property + + align:start position:0% + + + + align:start position:0% + +2 parent might be + + align:start position:0% + + + + align:start position:0% + +red property three + + align:start position:0% + + + + align:start position:0% + +sorry okay the good news is that + + align:start position:0% +sorry okay the good news is that + + + align:start position:0% +sorry okay the good news is that +property four is still true because + + align:start position:0% +property four is still true because + + + align:start position:0% +property four is still true because +property four is just counting numbers + + align:start position:0% +property four is just counting numbers + + + align:start position:0% +property four is just counting numbers +of black nodes down various paths that's + + align:start position:0% +of black nodes down various paths that's + + + align:start position:0% +of black nodes down various paths that's +really the hard property to maintain if + + align:start position:0% +really the hard property to maintain if + + + align:start position:0% +really the hard property to maintain if +we just add a new red node none of the + + align:start position:0% +we just add a new red node none of the + + + align:start position:0% +we just add a new red node none of the +black Heights change none of the number + + align:start position:0% +black Heights change none of the number + + + align:start position:0% +black Heights change none of the number +of black nodes along a path changes so + + align:start position:0% +of black nodes along a path changes so + + + align:start position:0% +of black nodes along a path changes so +this still has to hold the only thing we + + align:start position:0% +this still has to hold the only thing we + + + align:start position:0% +this still has to hold the only thing we +can violate is property 3 that's + + align:start position:0% +can violate is property 3 that's + + + align:start position:0% +can violate is property 3 that's +reasonable we know we've got to violate + + align:start position:0% +reasonable we know we've got to violate + + + align:start position:0% +reasonable we know we've got to violate +something at at the beginning just we + + align:start position:0% +something at at the beginning just we + + + align:start position:0% +something at at the beginning just we +can't just do a binary search tree + + align:start position:0% +can't just do a binary search tree + + + align:start position:0% +can't just do a binary search tree +insert + + align:start position:0% +insert + + + align:start position:0% +insert +okay so let's give it a + + align:start position:0% +okay so let's give it a + + + align:start position:0% +okay so let's give it a +try on this tree + + align:start position:0% + + + + align:start position:0% + +uh I should say what we're how we're + + align:start position:0% +uh I should say what we're how we're + + + align:start position:0% +uh I should say what we're how we're +going to fix + + align:start position:0% +going to fix + + + align:start position:0% +going to fix +this how do we fix uh property + + align:start position:0% +this how do we fix uh property + + + align:start position:0% +this how do we fix uh property +three we're going to move the violation + + align:start position:0% +three we're going to move the violation + + + align:start position:0% +three we're going to move the violation +of + + align:start position:0% +of + + + align:start position:0% +of +three up the + + align:start position:0% + + + + align:start position:0% + +tree so we're going to start at node X + + align:start position:0% +tree so we're going to start at node X + + + align:start position:0% +tree so we're going to start at node X +and move up towards the + + align:start position:0% +and move up towards the + + + align:start position:0% +and move up towards the +root + + align:start position:0% +root + + + align:start position:0% +root +um this is via recoloring only thing + + align:start position:0% +um this is via recoloring only thing + + + align:start position:0% +um this is via recoloring only thing +initially we'll do is recoloring until + + align:start position:0% +initially we'll do is recoloring until + + + align:start position:0% +initially we'll do is recoloring until +we get to some + + align:start position:0% + + + + align:start position:0% + +point where we can fix the violation + + align:start position:0% +point where we can fix the violation + + + align:start position:0% +point where we can fix the violation +using a + + align:start position:0% + + + + align:start position:0% + +rotation and probably also + + align:start position:0% + + + + align:start position:0% + +recoloring okay so let's see this + + align:start position:0% +recoloring okay so let's see this + + + align:start position:0% +recoloring okay so let's see this +algorithm in + + align:start position:0% +algorithm in + + + align:start position:0% +algorithm in +action um I want to copy this tree and + + align:start position:0% +action um I want to copy this tree and + + + align:start position:0% +action um I want to copy this tree and +you're going to have to copy it too so + + align:start position:0% +you're going to have to copy it too so + + + align:start position:0% +you're going to have to copy it too so +I'll just redraw it instead of modifying + + align:start position:0% +I'll just redraw it instead of modifying + + + align:start position:0% +I'll just redraw it instead of modifying +that + + align:start position:0% + + + + align:start position:0% + +diagram so we have this nice red black + + align:start position:0% +diagram so we have this nice red black + + + align:start position:0% +diagram so we have this nice red black +tree and we'll try inserting a new value + + align:start position:0% +tree and we'll try inserting a new value + + + align:start position:0% +tree and we'll try inserting a new value +of + + align:start position:0% + + + + align:start position:0% + +15 22 is + + align:start position:0% + + + + align:start position:0% + +black 22 is the New + + align:start position:0% + + + + align:start position:0% + +Black okay that should be the same tree + + align:start position:0% +Black okay that should be the same tree + + + align:start position:0% +Black okay that should be the same tree +so now I'm I'm choosing the number 15 to + + align:start position:0% +so now I'm I'm choosing the number 15 to + + + align:start position:0% +so now I'm I'm choosing the number 15 to +insert because that will show a fairly + + align:start position:0% +insert because that will show a fairly + + + align:start position:0% +insert because that will show a fairly +interesting insertion sometimes + + align:start position:0% +interesting insertion sometimes + + + align:start position:0% +interesting insertion sometimes +insertion doesn't take very much work we + + align:start position:0% +insertion doesn't take very much work we + + + align:start position:0% +insertion doesn't take very much work we +just do a rotation and we're done um + + align:start position:0% +just do a rotation and we're done um + + + align:start position:0% +just do a rotation and we're done um +here I'd like to look at + + align:start position:0% +here I'd like to look at + + + align:start position:0% +here I'd like to look at +a an interesting case so we insert 15 15 + + align:start position:0% +a an interesting case so we insert 15 15 + + + align:start position:0% +a an interesting case so we insert 15 15 +is bigger than seven it's less than 18 + + align:start position:0% +is bigger than seven it's less than 18 + + + align:start position:0% +is bigger than seven it's less than 18 +it's bigger than 10 it's bigger than 11 + + align:start position:0% +it's bigger than 10 it's bigger than 11 + + + align:start position:0% +it's bigger than 10 it's bigger than 11 +so 15 goes + + align:start position:0% +so 15 goes + + + align:start position:0% +so 15 goes +here so we add a new red node of 15 and + + align:start position:0% +here so we add a new red node of 15 and + + + align:start position:0% +here so we add a new red node of 15 and +it has two black leaves hanging off of + + align:start position:0% +it has two black leaves hanging off of + + + align:start position:0% +it has two black leaves hanging off of +it replaced one black Leaf now we have + + align:start position:0% +it replaced one black Leaf now we have + + + align:start position:0% +it replaced one black Leaf now we have +two okay + + align:start position:0% + + + + align:start position:0% + +now we violate property three because we + + align:start position:0% +now we violate property three because we + + + align:start position:0% +now we violate property three because we +added a new red child of a red node so + + align:start position:0% +added a new red child of a red node so + + + align:start position:0% +added a new red child of a red node so +now we have two consecutive red nodes in + + align:start position:0% +now we have two consecutive red nodes in + + + align:start position:0% +now we have two consecutive red nodes in +a root to Leaf path we'd like to make + + align:start position:0% +a root to Leaf path we'd like to make + + + align:start position:0% +a root to Leaf path we'd like to make +this black but that would screw up the + + align:start position:0% +this black but that would screw up the + + + align:start position:0% +this black but that would screw up the +black Heights because now this node + + align:start position:0% +black Heights because now this node + + + align:start position:0% +black Heights because now this node +would have one black node over here and + + align:start position:0% +would have one black node over here and + + + align:start position:0% +would have one black node over here and +two black nodes down this path so that's + + align:start position:0% +two black nodes down this path so that's + + + align:start position:0% +two black nodes down this path so that's +not + + align:start position:0% +not + + + align:start position:0% +not +good what can we do well let's try to + + align:start position:0% +good what can we do well let's try to + + + align:start position:0% +good what can we do well let's try to +recolor um + + align:start position:0% + + + + align:start position:0% + +recolor + + align:start position:0% +recolor + + + align:start position:0% +recolor +yes this it's always uh takes a little + + align:start position:0% +yes this it's always uh takes a little + + + align:start position:0% +yes this it's always uh takes a little +while to remember + + align:start position:0% +while to remember + + + align:start position:0% +while to remember +so our fix is going to be to recolor and + + align:start position:0% +so our fix is going to be to recolor and + + + align:start position:0% +so our fix is going to be to recolor and +the first thing that struck me which + + align:start position:0% +the first thing that struck me which + + + align:start position:0% +the first thing that struck me which +doesn't work is we try to recolor around + + align:start position:0% +doesn't work is we try to recolor around + + + align:start position:0% +doesn't work is we try to recolor around +here it doesn't look so good cuz you + + align:start position:0% +here it doesn't look so good cuz you + + + align:start position:0% +here it doesn't look so good cuz you +know we've got red stuff down here but + + align:start position:0% +know we've got red stuff down here but + + + align:start position:0% +know we've got red stuff down here but +we've got a black note over here so we + + align:start position:0% +we've got a black note over here so we + + + align:start position:0% +we've got a black note over here so we +can't make this one red and this one + + align:start position:0% +can't make this one red and this one + + + align:start position:0% +can't make this one red and this one +black it wouldn't quite work uh if we + + align:start position:0% +black it wouldn't quite work uh if we + + + align:start position:0% +black it wouldn't quite work uh if we +look up a little higher at the + + align:start position:0% +look up a little higher at the + + + align:start position:0% +look up a little higher at the +grandparent of 15 up here we have a + + align:start position:0% +grandparent of 15 up here we have a + + + align:start position:0% +grandparent of 15 up here we have a +black node here and two red children + + align:start position:0% +black node here and two red children + + + align:start position:0% +black node here and two red children +that's actually pretty good news because + + align:start position:0% +that's actually pretty good news because + + + align:start position:0% +that's actually pretty good news because +we could instead make that two black + + align:start position:0% +we could instead make that two black + + + align:start position:0% +we could instead make that two black +children and a red parent okay locally + + align:start position:0% +children and a red parent okay locally + + + align:start position:0% +children and a red parent okay locally +that's going to be fine it's not going + + align:start position:0% +that's going to be fine it's not going + + + align:start position:0% +that's going to be fine it's not going +to change any black Heights because uh + + align:start position:0% +to change any black Heights because uh + + + align:start position:0% +to change any black Heights because uh +any path that went through these nodes + + align:start position:0% +any path that went through these nodes + + + align:start position:0% +any path that went through these nodes +before will still go through the same + + align:start position:0% +before will still go through the same + + + align:start position:0% +before will still go through the same +number of black nodes instead of going + + align:start position:0% +number of black nodes instead of going + + + align:start position:0% +number of black nodes instead of going +through a black node always here it will + + align:start position:0% +through a black node always here it will + + + align:start position:0% +through a black node always here it will +go through a black node either here or + + align:start position:0% +go through a black node either here or + + + align:start position:0% +go through a black node either here or +here CU paths always go down to the + + align:start position:0% +here CU paths always go down to the + + + align:start position:0% +here CU paths always go down to the +leaves so that's what we're going to do + + align:start position:0% +leaves so that's what we're going to do + + + align:start position:0% +leaves so that's what we're going to do +recolor these + + align:start position:0% +recolor these + + + align:start position:0% +recolor these +guys and we'll get 10 which is red we'll + + align:start position:0% +guys and we'll get 10 which is red we'll + + + align:start position:0% +guys and we'll get 10 which is red we'll +get eight which is black 11 which is + + align:start position:0% +get eight which is black 11 which is + + + align:start position:0% +get eight which is black 11 which is +black and these things don't change + + align:start position:0% +black and these things don't change + + + align:start position:0% +black and these things don't change +everything else doesn't change we're + + align:start position:0% +everything else doesn't change we're + + + align:start position:0% +everything else doesn't change we're +going to leave 15 red it's no longer in + + align:start position:0% +going to leave 15 red it's no longer in + + + align:start position:0% +going to leave 15 red it's no longer in +violation 15 is great cuz now it's + + align:start position:0% +violation 15 is great cuz now it's + + + align:start position:0% +violation 15 is great cuz now it's +parent is black we now have a new + + align:start position:0% +parent is black we now have a new + + + align:start position:0% +parent is black we now have a new +violation up here with with + + align:start position:0% +violation up here with with + + + align:start position:0% +violation up here with with +18 18 is also + + align:start position:0% +18 18 is also + + + align:start position:0% +18 18 is also +red that's the only violation we have in + + align:start position:0% +red that's the only violation we have in + + + align:start position:0% +red that's the only violation we have in +general we'll have at most one violation + + align:start position:0% +general we'll have at most one violation + + + align:start position:0% +general we'll have at most one violation +at any time till we fix it and we'll + + align:start position:0% +at any time till we fix it and we'll + + + align:start position:0% +at any time till we fix it and we'll +have zero + + align:start position:0% + + + + align:start position:0% + +violations + + align:start position:0% +violations + + + align:start position:0% +violations +okay so now we have a violation between + + align:start position:0% +okay so now we have a violation between + + + align:start position:0% +okay so now we have a violation between +10 and 18 + + align:start position:0% + + + + align:start position:0% + +somehow always counterintuitive to me I + + align:start position:0% +somehow always counterintuitive to me I + + + align:start position:0% +somehow always counterintuitive to me I +have to look at the cheat sheet again + + align:start position:0% +have to look at the cheat sheet again + + + align:start position:0% +have to look at the cheat sheet again +all + + align:start position:0% +all + + + align:start position:0% +all +right + + align:start position:0% +right + + + align:start position:0% +right +really no okay good I was going to say + + align:start position:0% +really no okay good I was going to say + + + align:start position:0% +really no okay good I was going to say +we can't recolor anymore good I'm not + + align:start position:0% +we can't recolor anymore good I'm not + + + align:start position:0% +we can't recolor anymore good I'm not +that bad so what we'd like to do is + + align:start position:0% +that bad so what we'd like to do is + + + align:start position:0% +that bad so what we'd like to do is +again look at the grandparent of 10 + + align:start position:0% +again look at the grandparent of 10 + + + align:start position:0% +again look at the grandparent of 10 +which is now seven the root of the tree + + align:start position:0% +which is now seven the root of the tree + + + align:start position:0% +which is now seven the root of the tree +it is black but it one of its children + + align:start position:0% +it is black but it one of its children + + + align:start position:0% +it is black but it one of its children +is black the other is red so we can't + + align:start position:0% +is black the other is red so we can't + + + align:start position:0% +is black the other is red so we can't +play the same game of taking the + + align:start position:0% +play the same game of taking the + + + align:start position:0% +play the same game of taking the +Blackness of and moving it down to the + + align:start position:0% +Blackness of and moving it down to the + + + align:start position:0% +Blackness of and moving it down to the +two children never mind that the Root's + + align:start position:0% +two children never mind that the Root's + + + align:start position:0% +two children never mind that the Root's +supposed to stay black we'll ignore that + + align:start position:0% +supposed to stay black we'll ignore that + + + align:start position:0% +supposed to stay black we'll ignore that +property for now we can't make these two + + align:start position:0% +property for now we can't make these two + + + align:start position:0% +property for now we can't make these two +black and make this one red because then + + align:start position:0% +black and make this one red because then + + + align:start position:0% +black and make this one red because then +we'd get an imbalance this one was + + align:start position:0% +we'd get an imbalance this one was + + + align:start position:0% +we'd get an imbalance this one was +already black so now paths going down + + align:start position:0% +already black so now paths going down + + + align:start position:0% +already black so now paths going down +here will have one fewer black node then + + align:start position:0% +here will have one fewer black node then + + + align:start position:0% +here will have one fewer black node then +paths going down here so we can't just + + align:start position:0% +paths going down here so we can't just + + + align:start position:0% +paths going down here so we can't just +recolor seven in its children so instead + + align:start position:0% +recolor seven in its children so instead + + + align:start position:0% +recolor seven in its children so instead +we've got to do a rotation we better be + + align:start position:0% +we've got to do a rotation we better be + + + align:start position:0% +we've got to do a rotation we better be +near the end so what I will do is rotate + + align:start position:0% +near the end so what I will do is rotate + + + align:start position:0% +near the end so what I will do is rotate +this Edge I'm going to rotate eight to + + align:start position:0% +this Edge I'm going to rotate eight to + + + align:start position:0% +this Edge I'm going to rotate eight to +to the + + align:start position:0% +to the + + + align:start position:0% +to the +right so that's the next + + align:start position:0% +right so that's the next + + + align:start position:0% +right so that's the next +operation + + align:start position:0% + + + + align:start position:0% + +rotate right of 18 + + align:start position:0% + + + + align:start position:0% + +there'll be one more operation after + + align:start position:0% +there'll be one more operation after + + + align:start position:0% +there'll be one more operation after +this so we rotate right 18 so the root + + align:start position:0% +this so we rotate right 18 so the root + + + align:start position:0% +this so we rotate right 18 so the root +stays the same 7 three it's + + align:start position:0% +stays the same 7 three it's + + + align:start position:0% +stays the same 7 three it's +children now the right child of seven is + + align:start position:0% +children now the right child of seven is + + + align:start position:0% +children now the right child of seven is +no longer 18 is now + + align:start position:0% +no longer 18 is now + + + align:start position:0% +no longer 18 is now +10 18 becomes the right child of + + align:start position:0% +10 18 becomes the right child of + + + align:start position:0% +10 18 becomes the right child of +10 okay we have eight over + + align:start position:0% +10 okay we have eight over + + + align:start position:0% +10 okay we have eight over +here with its two children + + align:start position:0% +here with its two children + + + align:start position:0% +here with its two children +11 and 15 that sub tree fits in between + + align:start position:0% +11 and 15 that sub tree fits in between + + + align:start position:0% +11 and 15 that sub tree fits in between +10 and 18 so it goes + + align:start position:0% + + + + align:start position:0% + +here 11 and + + align:start position:0% + + + + align:start position:0% + +15 and then there's the right subtree + + align:start position:0% +15 and then there's the right subtree + + + align:start position:0% +15 and then there's the right subtree +everything to the right of 18 that goes + + align:start position:0% +everything to the right of 18 that goes + + + align:start position:0% +everything to the right of 18 that goes +over here + + align:start position:0% +over here + + + align:start position:0% +over here +22 and + + align:start position:0% + + + + align:start position:0% + +26 and hopefully I'm not changing any + + align:start position:0% +26 and hopefully I'm not changing any + + + align:start position:0% +26 and hopefully I'm not changing any +colors during that + + align:start position:0% +colors during that + + + align:start position:0% +colors during that +operation if I did let me know okay + + align:start position:0% +operation if I did let me know okay + + + align:start position:0% +operation if I did let me know okay +looks good so I still have this + + align:start position:0% +looks good so I still have this + + + align:start position:0% +looks good so I still have this +violation still in trouble between 10 + + align:start position:0% +violation still in trouble between 10 + + + align:start position:0% +violation still in trouble between 10 +and 18 but I've made this straighter + + align:start position:0% +and 18 but I've made this straighter + + + align:start position:0% +and 18 but I've made this straighter +okay that's what we want to do it turns + + align:start position:0% +okay that's what we want to do it turns + + + align:start position:0% +okay that's what we want to do it turns +out is make the connection between 18 + + align:start position:0% +out is make the connection between 18 + + + align:start position:0% +out is make the connection between 18 +The Violator and its grandparent a + + align:start position:0% +The Violator and its grandparent a + + + align:start position:0% +The Violator and its grandparent a +straight connection two rights or two + + align:start position:0% +straight connection two rights or two + + + align:start position:0% +straight connection two rights or two +lefts here we had a zigzag right left + + align:start position:0% +lefts here we had a zigzag right left + + + align:start position:0% +lefts here we had a zigzag right left +like to make it straight okay it doesn't + + align:start position:0% +like to make it straight okay it doesn't + + + align:start position:0% +like to make it straight okay it doesn't +look like a much more balanced tree than + + align:start position:0% +look like a much more balanced tree than + + + align:start position:0% +look like a much more balanced tree than +this one in fact it looks a little worse + + align:start position:0% +this one in fact it looks a little worse + + + align:start position:0% +this one in fact it looks a little worse +but what we can do is now rotate these + + align:start position:0% +but what we can do is now rotate these + + + align:start position:0% +but what we can do is now rotate these +guys or rather rotate this Edge I'm + + align:start position:0% +guys or rather rotate this Edge I'm + + + align:start position:0% +guys or rather rotate this Edge I'm +going to rotate seven to the left make + + align:start position:0% +going to rotate seven to the left make + + + align:start position:0% +going to rotate seven to the left make +10 the root and then things will start + + align:start position:0% +10 the root and then things will start + + + align:start position:0% +10 the root and then things will start +to look + + align:start position:0% + + + + align:start position:0% + +balanced this is a rotate + + align:start position:0% + + + + align:start position:0% + +left of + + align:start position:0% +left of + + + align:start position:0% +left of +seven and I'm also going to do some + + align:start position:0% +seven and I'm also going to do some + + + align:start position:0% +seven and I'm also going to do some +recoloring + + align:start position:0% +recoloring + + + align:start position:0% +recoloring +at the same time just to save me drawing + + align:start position:0% +at the same time just to save me drawing + + + align:start position:0% +at the same time just to save me drawing +one more picture because the root has to + + align:start position:0% +one more picture because the root has to + + + align:start position:0% +one more picture because the root has to +be black I'm going to make 10 black + + align:start position:0% +be black I'm going to make 10 black + + + align:start position:0% +be black I'm going to make 10 black +immediately I'll make seven red that's + + align:start position:0% +immediately I'll make seven red that's + + + align:start position:0% +immediately I'll make seven red that's +the change and then the rest is just a + + align:start position:0% + + + + align:start position:0% + +rotation so we have 18 over here think I + + align:start position:0% +rotation so we have 18 over here think I + + + align:start position:0% +rotation so we have 18 over here think I +actually have to rotate in order to keep + + align:start position:0% +actually have to rotate in order to keep + + + align:start position:0% +actually have to rotate in order to keep +some red Blackness here + + align:start position:0% + + + + align:start position:0% + +eight comes be between seven and 10 so + + align:start position:0% +eight comes be between seven and 10 so + + + align:start position:0% +eight comes be between seven and 10 so +it goes + + align:start position:0% + + + + align:start position:0% + +here 11 goes between 10 and 18 so it + + align:start position:0% +here 11 goes between 10 and 18 so it + + + align:start position:0% +here 11 goes between 10 and 18 so it +goes + + align:start position:0% + + + + align:start position:0% + +here 22 and 26 come after 18 + + align:start position:0% + + + + align:start position:0% + +okay now if I'm lucky I should satisfy + + align:start position:0% +okay now if I'm lucky I should satisfy + + + align:start position:0% +okay now if I'm lucky I should satisfy +all the properties that I want every + + align:start position:0% +all the properties that I want every + + + align:start position:0% +all the properties that I want every +node is red or black uh every red node + + align:start position:0% +node is red or black uh every red node + + + align:start position:0% +node is red or black uh every red node +has a black child this is the last place + + align:start position:0% +has a black child this is the last place + + + align:start position:0% +has a black child this is the last place +we changed red nodes have black children + + align:start position:0% +we changed red nodes have black children + + + align:start position:0% +we changed red nodes have black children +and all the black Heights should be well + + align:start position:0% +and all the black Heights should be well + + + align:start position:0% +and all the black Heights should be well +defined for for every node the number of + + align:start position:0% +defined for for every node the number of + + + align:start position:0% +defined for for every node the number of +uh black nodes along any root any node + + align:start position:0% +uh black nodes along any root any node + + + align:start position:0% +uh black nodes along any root any node +to Leaf path is the + + align:start position:0% +to Leaf path is the + + + align:start position:0% +to Leaf path is the +same and you check that was true before + + align:start position:0% +same and you check that was true before + + + align:start position:0% +same and you check that was true before +and I did a little bit of trickery with + + align:start position:0% +and I did a little bit of trickery with + + + align:start position:0% +and I did a little bit of trickery with +the recoloring here but it's still true + + align:start position:0% +the recoloring here but it's still true + + + align:start position:0% +the recoloring here but it's still true +okay and you can check that just locally + + align:start position:0% +okay and you can check that just locally + + + align:start position:0% +okay and you can check that just locally +around this rotation okay we'll do that + + align:start position:0% +around this rotation okay we'll do that + + + align:start position:0% +around this rotation okay we'll do that +in a little bit for now it's just an + + align:start position:0% +in a little bit for now it's just an + + + align:start position:0% +in a little bit for now it's just an +example it's not probably not terribly + + align:start position:0% +example it's not probably not terribly + + + align:start position:0% +example it's not probably not terribly +clear where these recoloring and + + align:start position:0% +clear where these recoloring and + + + align:start position:0% +clear where these recoloring and +rotations come from necessarily but it + + align:start position:0% +rotations come from necessarily but it + + + align:start position:0% +rotations come from necessarily but it +worked that at least convinces you that + + align:start position:0% +worked that at least convinces you that + + + align:start position:0% +worked that at least convinces you that +it it's + + align:start position:0% +it it's + + + align:start position:0% +it it's +possible and now we'll give a general + + align:start position:0% +possible and now we'll give a general + + + align:start position:0% +possible and now we'll give a general +algorithm for doing it any questions + + align:start position:0% +algorithm for doing it any questions + + + align:start position:0% +algorithm for doing it any questions +before we go + + align:start position:0% + + + + align:start position:0% + +on + + align:start position:0% +on + + + align:start position:0% +on +so it's not exactly uh + + align:start position:0% +so it's not exactly uh + + + align:start position:0% +so it's not exactly uh +I mean just writing down the algorithm + + align:start position:0% +I mean just writing down the algorithm + + + align:start position:0% +I mean just writing down the algorithm +is not terribly + + align:start position:0% +is not terribly + + + align:start position:0% +is not terribly +intuitive it's red black trees are the + + align:start position:0% +intuitive it's red black trees are the + + + align:start position:0% +intuitive it's red black trees are the +sort of thing where you play around a + + align:start position:0% +sort of thing where you play around a + + + align:start position:0% +sort of thing where you play around a +bit you you say okay I'm going to just + + align:start position:0% +bit you you say okay I'm going to just + + + align:start position:0% +bit you you say okay I'm going to just +think about recoloring and rotations + + align:start position:0% +think about recoloring and rotations + + + align:start position:0% +think about recoloring and rotations +let's restrict myself to those + + align:start position:0% +let's restrict myself to those + + + align:start position:0% +let's restrict myself to those +operations what could I do well I try to + + align:start position:0% +operations what could I do well I try to + + + align:start position:0% +operations what could I do well I try to +recolor if that works great pushes the + + align:start position:0% +recolor if that works great pushes the + + + align:start position:0% +recolor if that works great pushes the +problem up higher and there's only log n + + align:start position:0% +problem up higher and there's only log n + + + align:start position:0% +problem up higher and there's only log n +levels order order log n levels so + + align:start position:0% +levels order order log n levels so + + + align:start position:0% +levels order order log n levels so +that's going to take order log and time + + align:start position:0% +that's going to take order log and time + + + align:start position:0% +that's going to take order log and time +at some point I'll get stuck I can't + + align:start position:0% +at some point I'll get stuck I can't + + + align:start position:0% +at some point I'll get stuck I can't +recolor anymore then it turns out a + + align:start position:0% +recolor anymore then it turns out a + + + align:start position:0% +recolor anymore then it turns out a +couple of rotations will do it always + + align:start position:0% +couple of rotations will do it always + + + align:start position:0% +couple of rotations will do it always +two rotations will + + align:start position:0% +two rotations will + + + align:start position:0% +two rotations will +suffice and you just play with it and + + align:start position:0% +suffice and you just play with it and + + + align:start position:0% +suffice and you just play with it and +and that turns out to + + align:start position:0% +and that turns out to + + + align:start position:0% +and that turns out to +work and here's + + align:start position:0% + + + + align:start position:0% + +how Okay so let's suppose we have a a + + align:start position:0% +how Okay so let's suppose we have a a + + + align:start position:0% +how Okay so let's suppose we have a a +red black tree and an value X we want to + + align:start position:0% +red black tree and an value X we want to + + + align:start position:0% +red black tree and an value X we want to +insert here's the algorithm first we + + align:start position:0% +insert here's the algorithm first we + + + align:start position:0% +insert here's the algorithm first we +insert it into the + + align:start position:0% +insert it into the + + + align:start position:0% +insert it into the +BST so that we know + + align:start position:0% + + + + align:start position:0% + +then we color the node red and here I'm + + align:start position:0% +then we color the node red and here I'm + + + align:start position:0% +then we color the node red and here I'm +going to use a slightly more precise + + align:start position:0% +going to use a slightly more precise + + + align:start position:0% +going to use a slightly more precise +notation color is a field of + + align:start position:0% + + + + align:start position:0% + +X and now we're going to walk our way up + + align:start position:0% +X and now we're going to walk our way up + + + align:start position:0% +X and now we're going to walk our way up +the tree with a Y Loop until we get to + + align:start position:0% +the tree with a Y Loop until we get to + + + align:start position:0% +the tree with a Y Loop until we get to +the + + align:start position:0% +the + + + align:start position:0% +the +root + + align:start position:0% +root + + + align:start position:0% +root +or until we reach a black + + align:start position:0% + + + + align:start position:0% + +node so so in general X initially is + + align:start position:0% +node so so in general X initially is + + + align:start position:0% +node so so in general X initially is +going to be the element that we inserted + + align:start position:0% +going to be the element that we inserted + + + align:start position:0% +going to be the element that we inserted +but we're going to move X up the tree if + + align:start position:0% +but we're going to move X up the tree if + + + align:start position:0% +but we're going to move X up the tree if +ever we find that X is a black node + + align:start position:0% +ever we find that X is a black node + + + align:start position:0% +ever we find that X is a black node +we're happy because maybe it's parent is + + align:start position:0% +we're happy because maybe it's parent is + + + align:start position:0% +we're happy because maybe it's parent is +red maybe it isn't I don't care black + + align:start position:0% +red maybe it isn't I don't care black + + + align:start position:0% +red maybe it isn't I don't care black +nodes can have arbitrarily colored + + align:start position:0% +nodes can have arbitrarily colored + + + align:start position:0% +nodes can have arbitrarily colored +parents it's red nodes that we worry + + align:start position:0% +parents it's red nodes that we worry + + + align:start position:0% +parents it's red nodes that we worry +about and so if x is red we have to keep + + align:start position:0% +about and so if x is red we have to keep + + + align:start position:0% +about and so if x is red we have to keep +doing this + + align:start position:0% +doing this + + + align:start position:0% +doing this +Loop uh of course just wrote the wrong + + align:start position:0% +Loop uh of course just wrote the wrong + + + align:start position:0% +Loop uh of course just wrote the wrong +one while the color is red we're going + + align:start position:0% +one while the color is red we're going + + + align:start position:0% +one while the color is red we're going +to keep doing this + + align:start position:0% + + + + align:start position:0% + +so there are three + + align:start position:0% +so there are three + + + align:start position:0% +so there are three +cases well or six depending on how you + + align:start position:0% +cases well or six depending on how you + + + align:start position:0% +cases well or six depending on how you +count that's what makes this a little + + align:start position:0% +count that's what makes this a little + + + align:start position:0% +count that's what makes this a little +bit tricky to + + align:start position:0% + + + + align:start position:0% + +memorize okay but there are some + + align:start position:0% +memorize okay but there are some + + + align:start position:0% +memorize okay but there are some +symmetric uh situations let me draw + + align:start position:0% +symmetric uh situations let me draw + + + align:start position:0% +symmetric uh situations let me draw +them what we care about I've argued is + + align:start position:0% +them what we care about I've argued is + + + align:start position:0% +them what we care about I've argued is +between X and it's grandparent so I'm + + align:start position:0% +between X and it's grandparent so I'm + + + align:start position:0% +between X and it's grandparent so I'm +using p of X here to denote parent of X + + align:start position:0% +using p of X here to denote parent of X + + + align:start position:0% +using p of X here to denote parent of X +just because it's shorter so P of P of X + + align:start position:0% +just because it's shorter so P of P of X + + + align:start position:0% +just because it's shorter so P of P of X +is X is + + align:start position:0% +is X is + + + align:start position:0% +is X is +grandparent left of P of P of X is the + + align:start position:0% +grandparent left of P of P of X is the + + + align:start position:0% +grandparent left of P of P of X is the +left child so what I'm interested in is + + align:start position:0% +left child so what I'm interested in is + + + align:start position:0% +left child so what I'm interested in is +I look at X and if I don't assign any + + align:start position:0% +I look at X and if I don't assign any + + + align:start position:0% +I look at X and if I don't assign any +directions you know X is the child of + + align:start position:0% +directions you know X is the child of + + + align:start position:0% +directions you know X is the child of +some P of X + + align:start position:0% +some P of X + + + align:start position:0% +some P of X +and P of X is the parent of is the child + + align:start position:0% +and P of X is the parent of is the child + + + align:start position:0% +and P of X is the parent of is the child +of the grandparent P of P of X now these + + align:start position:0% +of the grandparent P of P of X now these + + + align:start position:0% +of the grandparent P of P of X now these +edges aren't vertical they're either + + align:start position:0% +edges aren't vertical they're either + + + align:start position:0% +edges aren't vertical they're either +left or right and I care about which one + + align:start position:0% +left or right and I care about which one + + + align:start position:0% +left or right and I care about which one +in particular I'm looking at whether the + + align:start position:0% +in particular I'm looking at whether the + + + align:start position:0% +in particular I'm looking at whether the +parent is the left child of of the + + align:start position:0% +parent is the left child of of the + + + align:start position:0% +parent is the left child of of the +grandparent so I want to know does it + + align:start position:0% +grandparent so I want to know does it + + + align:start position:0% +grandparent so I want to know does it +look + + align:start position:0% + + + + align:start position:0% + +like + + align:start position:0% +like + + + align:start position:0% +like +this okay and I don't know whether X is + + align:start position:0% +this okay and I don't know whether X is + + + align:start position:0% +this okay and I don't know whether X is +to the left or to the right of the + + align:start position:0% +to the left or to the right of the + + + align:start position:0% +to the left or to the right of the +parent but is parent of X the left child + + align:start position:0% +parent but is parent of X the left child + + + align:start position:0% +parent but is parent of X the left child +of P of P of X or is it the right + + align:start position:0% +of P of P of X or is it the right + + + align:start position:0% +of P of P of X or is it the right +child and these two cases are totally + + align:start position:0% +child and these two cases are totally + + + align:start position:0% +child and these two cases are totally +symmetric but I need to assume it's one + + align:start position:0% +symmetric but I need to assume it's one + + + align:start position:0% +symmetric but I need to assume it's one +way or the other other otherwise I can't + + align:start position:0% +way or the other other otherwise I can't + + + align:start position:0% +way or the other other otherwise I can't +draw the + + align:start position:0% + + + + align:start position:0% + +pictures Okay so this will be let's call + + align:start position:0% +pictures Okay so this will be let's call + + + align:start position:0% +pictures Okay so this will be let's call +it category a and this is category B and + + align:start position:0% +it category a and this is category B and + + + align:start position:0% +it category a and this is category B and +I'm going to tell you what to do in + + align:start position:0% +I'm going to tell you what to do in + + + align:start position:0% +I'm going to tell you what to do in +category a and category B is symmetric + + align:start position:0% +category a and category B is symmetric + + + align:start position:0% +category a and category B is symmetric +you just flip left and right okay so + + align:start position:0% +you just flip left and right okay so + + + align:start position:0% +you just flip left and right okay so +this this is + + align:start position:0% + + + + align:start position:0% + +a So within category a there are three + + align:start position:0% +a So within category a there are three + + + align:start position:0% +a So within category a there are three +cases and within category B there's the + + align:start position:0% +cases and within category B there's the + + + align:start position:0% +cases and within category B there's the +same three cases just + + align:start position:0% +same three cases just + + + align:start position:0% +same three cases just +reversed so what we're going to do is + + align:start position:0% +reversed so what we're going to do is + + + align:start position:0% +reversed so what we're going to do is +look at the other child of the + + align:start position:0% + + + + align:start position:0% + +grandparent this is one reason why we + + align:start position:0% +grandparent this is one reason why we + + + align:start position:0% +grandparent this is one reason why we +sort of need to know which way we're + + align:start position:0% +sort of need to know which way we're + + + align:start position:0% +sort of need to know which way we're +looking um if the parent of X is the + + align:start position:0% +looking um if the parent of X is the + + + align:start position:0% +looking um if the parent of X is the +left child of the grandparent we're + + align:start position:0% +left child of the grandparent we're + + + align:start position:0% +left child of the grandparent we're +going to look at the other child of the + + align:start position:0% +going to look at the other child of the + + + align:start position:0% +going to look at the other child of the +grandparent which would be the right + + align:start position:0% +grandparent which would be the right + + + align:start position:0% +grandparent which would be the right +child of the grandparent call that node + + align:start position:0% +child of the grandparent call that node + + + align:start position:0% +child of the grandparent call that node +y this is also known as the uncle or the + + align:start position:0% +y this is also known as the uncle or the + + + align:start position:0% +y this is also known as the uncle or the +aunt of X depending on whether Y is male + + align:start position:0% +aunt of X depending on whether Y is male + + + align:start position:0% +aunt of X depending on whether Y is male +or + + align:start position:0% +or + + + align:start position:0% +or +female okay so this is Uncle or Aunt + + align:start position:0% +female okay so this is Uncle or Aunt + + + align:start position:0% +female okay so this is Uncle or Aunt +unfortunately in English there is no + + align:start position:0% +unfortunately in English there is no + + + align:start position:0% +unfortunately in English there is no +gender-free version of this as far as I + + align:start position:0% +gender-free version of this as far as I + + + align:start position:0% +gender-free version of this as far as I +know with parent child but no uncle aunt + + align:start position:0% +know with parent child but no uncle aunt + + + align:start position:0% +know with parent child but no uncle aunt +I'm sure we could come up with + + align:start position:0% +I'm sure we could come up with + + + align:start position:0% +I'm sure we could come up with +one I'm not going to try it's going to + + align:start position:0% +one I'm not going to try it's going to + + + align:start position:0% +one I'm not going to try it's going to +sound + + align:start position:0% +sound + + + align:start position:0% +sound +bad um all right so why do I care about + + align:start position:0% +bad um all right so why do I care about + + + align:start position:0% +bad um all right so why do I care about +why because I want to see if I can do + + align:start position:0% +why because I want to see if I can do + + + align:start position:0% +why because I want to see if I can do +this recoloring step the recoloring idea + + align:start position:0% +this recoloring step the recoloring idea + + + align:start position:0% +this recoloring step the recoloring idea +was well the grandparent is let's say + + align:start position:0% +was well the grandparent is let's say + + + align:start position:0% +was well the grandparent is let's say +it's black if I can push the Blackness + + align:start position:0% +it's black if I can push the Blackness + + + align:start position:0% +it's black if I can push the Blackness +of the parent of the grandparent down + + align:start position:0% +of the parent of the grandparent down + + + align:start position:0% +of the parent of the grandparent down +into the two + + align:start position:0% +into the two + + + align:start position:0% +into the two +children then if both of these are red + + align:start position:0% +children then if both of these are red + + + align:start position:0% +children then if both of these are red +in other words then I'd be happy then I + + align:start position:0% +in other words then I'd be happy then I + + + align:start position:0% +in other words then I'd be happy then I +push the problem up this guy's Now red + + align:start position:0% +push the problem up this guy's Now red + + + align:start position:0% +push the problem up this guy's Now red +this guy's black so these two are all + + align:start position:0% +this guy's black so these two are all + + + align:start position:0% +this guy's black so these two are all +right this one may violate the + + align:start position:0% +right this one may violate the + + + align:start position:0% +right this one may violate the +great-grandparent but we'll just keep + + align:start position:0% +great-grandparent but we'll just keep + + + align:start position:0% +great-grandparent but we'll just keep +going up and that will be fine so if + + align:start position:0% +going up and that will be fine so if + + + align:start position:0% +going up and that will be fine so if +we're lucky Y is red then we can just do + + align:start position:0% + + + + align:start position:0% + +recoloring so if the color of + + align:start position:0% +recoloring so if the color of + + + align:start position:0% +recoloring so if the color of +Y is + + align:start position:0% + + + + align:start position:0% + +red + + align:start position:0% +red + + + align:start position:0% +red +then we will recolor and I'm going to + + align:start position:0% +then we will recolor and I'm going to + + + align:start position:0% +then we will recolor and I'm going to +defer this to a picture called case + + align:start position:0% +defer this to a picture called case + + + align:start position:0% +defer this to a picture called case +one okay let me first tell you how the + + align:start position:0% +one okay let me first tell you how the + + + align:start position:0% +one okay let me first tell you how the +cases break up and then we'll see how + + align:start position:0% +cases break up and then we'll see how + + + align:start position:0% +cases break up and then we'll see how +they + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% + + + + align:start position:0% + +work so if we're not in case one so this + + align:start position:0% +work so if we're not in case one so this + + + align:start position:0% +work so if we're not in case one so this +else should be aligned with that + + align:start position:0% +else should be aligned with that + + + align:start position:0% +else should be aligned with that +then then we're either in case two or + + align:start position:0% +then then we're either in case two or + + + align:start position:0% +then then we're either in case two or +three so here's the + + align:start position:0% +three so here's the + + + align:start position:0% +three so here's the +the + + align:start position:0% + + + + align:start position:0% + +dichotomy it turns out we've actually + + align:start position:0% +dichotomy it turns out we've actually + + + align:start position:0% +dichotomy it turns out we've actually +seen all of the cases maybe not a versus + + align:start position:0% +seen all of the cases maybe not a versus + + + align:start position:0% +seen all of the cases maybe not a versus +B but we've seen the case in the very + + align:start position:0% +B but we've seen the case in the very + + + align:start position:0% +B but we've seen the case in the very +beginning where we just recolored that's + + align:start position:0% +beginning where we just recolored that's + + + align:start position:0% +beginning where we just recolored that's +case one the next thing we saw is what + + align:start position:0% +case one the next thing we saw is what + + + align:start position:0% +case one the next thing we saw is what +well it was kind of annoying that the + + align:start position:0% +well it was kind of annoying that the + + + align:start position:0% +well it was kind of annoying that the +grandparent and 10 so seven and 10 were + + align:start position:0% +grandparent and 10 so seven and 10 were + + + align:start position:0% +grandparent and 10 so seven and 10 were +not straight they were zigzagged so case + + align:start position:0% +not straight they were zigzagged so case + + + align:start position:0% +not straight they were zigzagged so case +two is when they're + + align:start position:0% +two is when they're + + + align:start position:0% +two is when they're +zigzagged turns out that's + + align:start position:0% +zigzagged turns out that's + + + align:start position:0% +zigzagged turns out that's +uh if x is the right of the you know if + + align:start position:0% +uh if x is the right of the you know if + + + align:start position:0% +uh if x is the right of the you know if +x is the right child of its parent and + + align:start position:0% +x is the right child of its parent and + + + align:start position:0% +x is the right child of its parent and +the parent is the left child of the + + align:start position:0% +the parent is the left child of the + + + align:start position:0% +the parent is the left child of the +grandparent that's what we've assumed so + + align:start position:0% +grandparent that's what we've assumed so + + + align:start position:0% +grandparent that's what we've assumed so +far that is case + + align:start position:0% + + + + align:start position:0% + +two okay the other case is that X is the + + align:start position:0% +two okay the other case is that X is the + + + align:start position:0% +two okay the other case is that X is the +left child of its parent so then we have + + align:start position:0% +left child of its parent so then we have + + + align:start position:0% +left child of its parent so then we have +a left chain X parent of X grandparent + + align:start position:0% +a left chain X parent of X grandparent + + + align:start position:0% +a left chain X parent of X grandparent +of X that is case three + + align:start position:0% + + + + align:start position:0% + +okay I did not write else here because + + align:start position:0% +okay I did not write else here because + + + align:start position:0% +okay I did not write else here because +what case two does is it reduces to case + + align:start position:0% +what case two does is it reduces to case + + + align:start position:0% +what case two does is it reduces to case +three so in case two we're going to do + + align:start position:0% +three so in case two we're going to do + + + align:start position:0% +three so in case two we're going to do +the stuff that's here and then we're + + align:start position:0% +the stuff that's here and then we're + + + align:start position:0% +the stuff that's here and then we're +going to do the stuff here we're in case + + align:start position:0% +going to do the stuff here we're in case + + + align:start position:0% +going to do the stuff here we're in case +three we just do the stuff here we're in + + align:start position:0% +three we just do the stuff here we're in + + + align:start position:0% +three we just do the stuff here we're in +case one we just do the stuff + + align:start position:0% +case one we just do the stuff + + + align:start position:0% +case one we just do the stuff +here and then that finishes the three + + align:start position:0% +here and then that finishes the three + + + align:start position:0% +here and then that finishes the three +cases on the a side then up back to this + + align:start position:0% +cases on the a side then up back to this + + + align:start position:0% +cases on the a side then up back to this +if uh we say else this is case b + + align:start position:0% + + + + align:start position:0% + +um which is the same as + + align:start position:0% + + + + align:start position:0% + +a but reversing the Notions of left and + + align:start position:0% + + + + align:start position:0% + +right okay in the + + align:start position:0% +right okay in the + + + align:start position:0% +right okay in the +natural natural way every time we write + + align:start position:0% +natural natural way every time we write + + + align:start position:0% +natural natural way every time we write +left of something we instead write right + + align:start position:0% +left of something we instead write right + + + align:start position:0% +left of something we instead write right +of something and vice versa so this is + + align:start position:0% +of something and vice versa so this is + + + align:start position:0% +of something and vice versa so this is +really just flipping everything over + + align:start position:0% +really just flipping everything over + + + align:start position:0% +really just flipping everything over +we'll just focus on case on + + align:start position:0% +we'll just focus on case on + + + align:start position:0% +we'll just focus on case on +category a and let's see what we do in + + align:start position:0% +category a and let's see what we do in + + + align:start position:0% +category a and let's see what we do in +each of the three cases we've seen it in + + align:start position:0% +each of the three cases we've seen it in + + + align:start position:0% +each of the three cases we've seen it in +an example but let's do it + + align:start position:0% + + + + align:start position:0% + +generically let's do it + + align:start position:0% + + + + align:start position:0% + +here um oh there's sorry there's a + + align:start position:0% +here um oh there's sorry there's a + + + align:start position:0% +here um oh there's sorry there's a +little there's one more line to the + + align:start position:0% +little there's one more line to the + + + align:start position:0% +little there's one more line to the +algorithm I should say so aligned with + + align:start position:0% +algorithm I should say so aligned with + + + align:start position:0% +algorithm I should say so aligned with +here we color the root there's a chance + + align:start position:0% +here we color the root there's a chance + + + align:start position:0% +here we color the root there's a chance +when you do all of this the root becomes + + align:start position:0% +when you do all of this the root becomes + + + align:start position:0% +when you do all of this the root becomes +red we always want the root to be black + + align:start position:0% +red we always want the root to be black + + + align:start position:0% +red we always want the root to be black +if it's red we set it to Black at the + + align:start position:0% +if it's red we set it to Black at the + + + align:start position:0% +if it's red we set it to Black at the +very end of the + + align:start position:0% +very end of the + + + align:start position:0% +very end of the +algorithm + + align:start position:0% +algorithm + + + align:start position:0% +algorithm +um this does not change the black height + + align:start position:0% +um this does not change the black height + + + align:start position:0% +um this does not change the black height +property everything will still be fine + + align:start position:0% +property everything will still be fine + + + align:start position:0% +property everything will still be fine +because there's I mean every path either + + align:start position:0% +because there's I mean every path either + + + align:start position:0% +because there's I mean every path either +goes to the root or it doesn't every X + + align:start position:0% +goes to the root or it doesn't every X + + + align:start position:0% +goes to the root or it doesn't every X +to Leaf path so changing the root from + + align:start position:0% +to Leaf path so changing the root from + + + align:start position:0% +to Leaf path so changing the root from +red to Black is no problem it will + + align:start position:0% +red to Black is no problem it will + + + align:start position:0% +red to Black is no problem it will +increase the black Heights of everyone + + align:start position:0% +increase the black Heights of everyone + + + align:start position:0% +increase the black Heights of everyone +but they'll all stay uh all the paths + + align:start position:0% +but they'll all stay uh all the paths + + + align:start position:0% +but they'll all stay uh all the paths +will still have the same value just + + align:start position:0% +will still have the same value just + + + align:start position:0% +will still have the same value just +it'll be one + + align:start position:0% + + + + align:start position:0% + +larger so let's look at the three + + align:start position:0% + + + + align:start position:0% + +cases and I'm going to use some notation + + align:start position:0% +cases and I'm going to use some notation + + + align:start position:0% +cases and I'm going to use some notation +remember we had triangles in order to + + align:start position:0% +remember we had triangles in order to + + + align:start position:0% +remember we had triangles in order to +denote uh arbitrary sub trees when we + + align:start position:0% +denote uh arbitrary sub trees when we + + + align:start position:0% +denote uh arbitrary sub trees when we +defined a rotation I'm going to use + + align:start position:0% +defined a rotation I'm going to use + + + align:start position:0% +defined a rotation I'm going to use +triangle with a DOT on top to say that + + align:start position:0% +triangle with a DOT on top to say that + + + align:start position:0% +triangle with a DOT on top to say that +um + + align:start position:0% +um + + + align:start position:0% +um +this no this subtree has a black + + align:start position:0% +this no this subtree has a black + + + align:start position:0% +this no this subtree has a black +root so this when I fill something white + + align:start position:0% +root so this when I fill something white + + + align:start position:0% +root so this when I fill something white +it means black because I'm on a black + + align:start position:0% +it means black because I'm on a black + + + align:start position:0% +it means black because I'm on a black +board + + align:start position:0% +board + + + align:start position:0% +board +sorry okay + + align:start position:0% + + + + align:start position:0% + +and and I also have the property that + + align:start position:0% +and and I also have the property that + + + align:start position:0% +and and I also have the property that +each of these + + align:start position:0% +each of these + + + align:start position:0% +each of these +triangles have the same black height + + align:start position:0% + + + + align:start position:0% + +so this will let me make sure that the + + align:start position:0% +so this will let me make sure that the + + + align:start position:0% +so this will let me make sure that the +black height property property four is + + align:start position:0% +black height property property four is + + + align:start position:0% +black height property property four is +being + + align:start position:0% +being + + + align:start position:0% +being +preserved so let me just show you case + + align:start position:0% +preserved so let me just show you case + + + align:start position:0% +preserved so let me just show you case +one we always want to make sure property + + align:start position:0% +one we always want to make sure property + + + align:start position:0% +one we always want to make sure property +4 is preserved because it's really hard + + align:start position:0% +4 is preserved because it's really hard + + + align:start position:0% +4 is preserved because it's really hard +to get that back it's essentially the + + align:start position:0% +to get that back it's essentially the + + + align:start position:0% +to get that back it's essentially the +balance of the + + align:start position:0% +balance of the + + + align:start position:0% +balance of the +tree so let's suppose we have some nod C + + align:start position:0% +tree so let's suppose we have some nod C + + + align:start position:0% +tree so let's suppose we have some nod C +left child a right child + + align:start position:0% +left child a right child + + + align:start position:0% +left child a right child +B and some sub trees hanging off those + + align:start position:0% +B and some sub trees hanging off those + + + align:start position:0% +B and some sub trees hanging off those +guys and all of those sub trees have the + + align:start position:0% +guys and all of those sub trees have the + + + align:start position:0% +guys and all of those sub trees have the +same black + + align:start position:0% +same black + + + align:start position:0% +same black +height so in other words these things + + align:start position:0% +height so in other words these things + + + align:start position:0% +height so in other words these things +are all at the same + + align:start position:0% + + + + align:start position:0% + +level okay this uh is not quite what I + + align:start position:0% +level okay this uh is not quite what I + + + align:start position:0% +level okay this uh is not quite what I +wanted + + align:start position:0% +wanted + + + align:start position:0% +wanted +sorry I also so I'm considering this is + + align:start position:0% +sorry I also so I'm considering this is + + + align:start position:0% +sorry I also so I'm considering this is +node x x is red and his parent is red + + align:start position:0% +node x x is red and his parent is red + + + align:start position:0% +node x x is red and his parent is red +therefore we need to fix something we + + align:start position:0% +therefore we need to fix something we + + + align:start position:0% +therefore we need to fix something we +look at the node Y which is over here + + align:start position:0% +look at the node Y which is over here + + + align:start position:0% +look at the node Y which is over here +and I'll call it the key is D the node + + align:start position:0% +and I'll call it the key is D the node + + + align:start position:0% +and I'll call it the key is D the node +is called + + align:start position:0% +is called + + + align:start position:0% +is called +y okay it has sub trees hanging off as + + align:start position:0% +y okay it has sub trees hanging off as + + + align:start position:0% +y okay it has sub trees hanging off as +well all with the same black height so + + align:start position:0% +well all with the same black height so + + + align:start position:0% +well all with the same black height so +that will be true if if all of these + + align:start position:0% +that will be true if if all of these + + + align:start position:0% +that will be true if if all of these +nodes are red then all of these nodes + + align:start position:0% +nodes are red then all of these nodes + + + align:start position:0% +nodes are red then all of these nodes +have the same black height and therefore + + align:start position:0% +have the same black height and therefore + + + align:start position:0% +have the same black height and therefore +all of the child sub trees which have + + align:start position:0% +all of the child sub trees which have + + + align:start position:0% +all of the child sub trees which have +black roots all have to have the same + + align:start position:0% +black roots all have to have the same + + + align:start position:0% +black roots all have to have the same +black height as well okay so we're sort + + align:start position:0% +black height as well okay so we're sort + + + align:start position:0% +black height as well okay so we're sort +of looking at a big chunk of red + + align:start position:0% +of looking at a big chunk of red + + + align:start position:0% +of looking at a big chunk of red +children a red children's subtree of a + + align:start position:0% +children a red children's subtree of a + + + align:start position:0% +children a red children's subtree of a +black node looking at all all the stuff + + align:start position:0% +black node looking at all all the stuff + + + align:start position:0% +black node looking at all all the stuff +that happens to be red in case one y is + + align:start position:0% +that happens to be red in case one y is + + + align:start position:0% +that happens to be red in case one y is +red so it participates so a way to think + + align:start position:0% +red so it participates so a way to think + + + align:start position:0% +red so it participates so a way to think +of this is if we converted into the 2 + + align:start position:0% +of this is if we converted into the 2 + + + align:start position:0% +of this is if we converted into the 2 +three4 tree or tried to we would merge + + align:start position:0% +three4 tree or tried to we would merge + + + align:start position:0% +three4 tree or tried to we would merge +all of this stuff into one node that's + + align:start position:0% +all of this stuff into one node that's + + + align:start position:0% +all of this stuff into one node that's +essentially what we're doing here this + + align:start position:0% +essentially what we're doing here this + + + align:start position:0% +essentially what we're doing here this +is not a 234 tree though we now have + + align:start position:0% +is not a 234 tree though we now have + + + align:start position:0% +is not a 234 tree though we now have +five children which is bad this is why + + align:start position:0% +five children which is bad this is why + + + align:start position:0% +five children which is bad this is why +we want to fix + + align:start position:0% +we want to fix + + + align:start position:0% +we want to fix +it so we're going to + + align:start position:0% +it so we're going to + + + align:start position:0% +it so we're going to +recolor in case one + + align:start position:0% +recolor in case one + + + align:start position:0% +recolor in case one +and we're going to take C instead of + + align:start position:0% +and we're going to take C instead of + + + align:start position:0% +and we're going to take C instead of +making C black and a and d red we're + + align:start position:0% +making C black and a and d red we're + + + align:start position:0% +making C black and a and d red we're +going to make a and D black and C + + align:start position:0% + + + + align:start position:0% + +red so C is red a is + + align:start position:0% +red so C is red a is + + + align:start position:0% +red so C is red a is +black d is + + align:start position:0% +black d is + + + align:start position:0% +black d is +black + + align:start position:0% +black + + + align:start position:0% +black +and the subtes are the same B is the + + align:start position:0% +and the subtes are the same B is the + + + align:start position:0% +and the subtes are the same B is the +same still + + align:start position:0% + + + + align:start position:0% + +red okay now we need to check that we + + align:start position:0% +red okay now we need to check that we + + + align:start position:0% +red okay now we need to check that we +Preserve property four that all of the + + align:start position:0% +Preserve property four that all of the + + + align:start position:0% +Preserve property four that all of the +paths have the same number of black + + align:start position:0% +paths have the same number of black + + + align:start position:0% +paths have the same number of black +nodes that follows because we know we + + align:start position:0% +nodes that follows because we know we + + + align:start position:0% +nodes that follows because we know we +didn't touch these sub trees they all + + align:start position:0% +didn't touch these sub trees they all + + + align:start position:0% +didn't touch these sub trees they all +have the same black height and uh if you + + align:start position:0% +have the same black height and uh if you + + + align:start position:0% +have the same black height and uh if you +look at any path like all the paths from + + align:start position:0% +look at any path like all the paths from + + + align:start position:0% +look at any path like all the paths from +a are going to have that black height + + align:start position:0% +a are going to have that black height + + + align:start position:0% +a are going to have that black height +all the paths from C are going to have + + align:start position:0% +all the paths from C are going to have + + + align:start position:0% +all the paths from C are going to have +that black height plus one because + + align:start position:0% +that black height plus one because + + + align:start position:0% +that black height plus one because +there's a black node in all the left + + align:start position:0% +there's a black node in all the left + + + align:start position:0% +there's a black node in all the left +paths and there's a black node in all + + align:start position:0% +paths and there's a black node in all + + + align:start position:0% +paths and there's a black node in all +the right paths so all the black Heights + + align:start position:0% +the right paths so all the black Heights + + + align:start position:0% +the right paths so all the black Heights +all the black lengths are the same so + + align:start position:0% +all the black lengths are the same so + + + align:start position:0% +all the black lengths are the same so +this preserves property 4 and it fixes + + align:start position:0% +this preserves property 4 and it fixes + + + align:start position:0% +this preserves property 4 and it fixes +property three locally cuz B used to + + align:start position:0% +property three locally cuz B used to + + + align:start position:0% +property three locally cuz B used to +violate a now B uh does not violate + + align:start position:0% +violate a now B uh does not violate + + + align:start position:0% +violate a now B uh does not violate +anything C now might have to might be + + align:start position:0% +anything C now might have to might be + + + align:start position:0% +anything C now might have to might be +violated so what we're going to do is + + align:start position:0% +violated so what we're going to do is + + + align:start position:0% +violated so what we're going to do is +set X our new value of x will be C so it + + align:start position:0% +set X our new value of x will be C so it + + + align:start position:0% +set X our new value of x will be C so it +used to be B we move it up a couple + + align:start position:0% +used to be B we move it up a couple + + + align:start position:0% +used to be B we move it up a couple +levels or in the original tree yeah we + + align:start position:0% +levels or in the original tree yeah we + + + align:start position:0% +levels or in the original tree yeah we +also move it up a couple levels so we're + + align:start position:0% +also move it up a couple levels so we're + + + align:start position:0% +also move it up a couple levels so we're +making progress up the tree and then we + + align:start position:0% +making progress up the tree and then we + + + align:start position:0% +making progress up the tree and then we +continue this + + align:start position:0% +continue this + + + align:start position:0% +continue this +Loop that's case one recolor go up C May + + align:start position:0% +Loop that's case one recolor go up C May + + + align:start position:0% +Loop that's case one recolor go up C May +violate its parent in which case we have + + align:start position:0% +violate its parent in which case we have + + + align:start position:0% +violate its parent in which case we have +to recurse so we're recursing in some + + align:start position:0% +to recurse so we're recursing in some + + + align:start position:0% +to recurse so we're recursing in some +sense or continuing on + + align:start position:0% + + + + align:start position:0% + +C so now let's look at case two + + align:start position:0% + + + + align:start position:0% + +so I'm still in some sense defining this + + align:start position:0% +so I'm still in some sense defining this + + + align:start position:0% +so I'm still in some sense defining this +algorithm by picture this is some nice + + align:start position:0% +algorithm by picture this is some nice + + + align:start position:0% +algorithm by picture this is some nice +graphical programming language + + align:start position:0% + + + + align:start position:0% + +so let's draw case + + align:start position:0% + + + + align:start position:0% + +two + + align:start position:0% +two + + + align:start position:0% +two +um yeah I forgot to mention something + + align:start position:0% +um yeah I forgot to mention something + + + align:start position:0% +um yeah I forgot to mention something +about case one + + align:start position:0% +about case one + + + align:start position:0% +about case one +so I I drew some things here I uh what + + align:start position:0% +so I I drew some things here I uh what + + + align:start position:0% +so I I drew some things here I uh what +what do I actually know is true so let's + + align:start position:0% +what do I actually know is true so let's + + + align:start position:0% +what do I actually know is true so let's +go let's look at the algorithm which + + align:start position:0% +go let's look at the algorithm which + + + align:start position:0% +go let's look at the algorithm which +I've now reversed but um we are assuming + + align:start position:0% +I've now reversed but um we are assuming + + + align:start position:0% +I've now reversed but um we are assuming +that we're in category a in other words + + align:start position:0% +that we're in category a in other words + + + align:start position:0% +that we're in category a in other words +the parent is the left child of the + + align:start position:0% +the parent is the left child of the + + + align:start position:0% +the parent is the left child of the +grandparent so a is the left child of C + + align:start position:0% +grandparent so a is the left child of C + + + align:start position:0% +grandparent so a is the left child of C +that much I knew therefore Y is the + + align:start position:0% +that much I knew therefore Y is the + + + align:start position:0% +that much I knew therefore Y is the +right child + + align:start position:0% +right child + + + align:start position:0% +right child +D is the right child of C I didn't + + align:start position:0% +D is the right child of C I didn't + + + align:start position:0% +D is the right child of C I didn't +actually know whether B was the right + + align:start position:0% +actually know whether B was the right + + + align:start position:0% +actually know whether B was the right +child or the left child it didn't matter + + align:start position:0% +child or the left child it didn't matter + + + align:start position:0% +child or the left child it didn't matter +in case one it doesn't matter okay so I + + align:start position:0% +in case one it doesn't matter okay so I + + + align:start position:0% +in case one it doesn't matter okay so I +should have said um the children of a + + align:start position:0% +should have said um the children of a + + + align:start position:0% +should have said um the children of a +may be + + align:start position:0% +may be + + + align:start position:0% +may be +reversed but it's just the same + + align:start position:0% + + + + align:start position:0% + +picture okay I thought of this because + + align:start position:0% +picture okay I thought of this because + + + align:start position:0% +picture okay I thought of this because +in case two we care so case one we + + align:start position:0% +in case two we care so case one we + + + align:start position:0% +in case two we care so case one we +didn't really care in case two we say + + align:start position:0% +didn't really care in case two we say + + + align:start position:0% +didn't really care in case two we say +well uh case two is up there is X the + + align:start position:0% +well uh case two is up there is X the + + + align:start position:0% +well uh case two is up there is X the +right child of the parent or the left + + align:start position:0% +right child of the parent or the left + + + align:start position:0% +right child of the parent or the left +child if it's the right child we're in + + align:start position:0% +child if it's the right child we're in + + + align:start position:0% +child if it's the right child we're in +case two so now I really know that X + + align:start position:0% +case two so now I really know that X + + + align:start position:0% +case two so now I really know that X +here is which is B is the right child of + + align:start position:0% +here is which is B is the right child of + + + align:start position:0% +here is which is B is the right child of +a before I didn't know I didn't care now + + align:start position:0% +a before I didn't know I didn't care now + + + align:start position:0% +a before I didn't know I didn't care now +I'm assuming that it's this way okay Y + + align:start position:0% +I'm assuming that it's this way okay Y + + + align:start position:0% +I'm assuming that it's this way okay Y +is still over + + align:start position:0% +is still over + + + align:start position:0% +is still over +here and now we know that Y is black + + align:start position:0% +here and now we know that Y is black + + + align:start position:0% +here and now we know that Y is black +so y over here is a black node so now if + + align:start position:0% +so y over here is a black node so now if + + + align:start position:0% +so y over here is a black node so now if +I did the contraction trick all of these + + align:start position:0% +I did the contraction trick all of these + + + align:start position:0% +I did the contraction trick all of these +nodes a b and c would conglomerate into + + align:start position:0% +nodes a b and c would conglomerate into + + + align:start position:0% +nodes a b and c would conglomerate into +one I only have four children that + + align:start position:0% +one I only have four children that + + + align:start position:0% +one I only have four children that +actually looks pretty good why would not + + align:start position:0% +actually looks pretty good why would not + + + align:start position:0% +actually looks pretty good why would not +be involved because it's + + align:start position:0% +be involved because it's + + + align:start position:0% +be involved because it's +black + + align:start position:0% +black + + + align:start position:0% +black +okay so in this case we're going to do a + + align:start position:0% +okay so in this case we're going to do a + + + align:start position:0% +okay so in this case we're going to do a +left + + align:start position:0% + + + + align:start position:0% + +rotation on a + + align:start position:0% + + + + align:start position:0% + +so we take this Edge we turn it 90° what + + align:start position:0% +so we take this Edge we turn it 90° what + + + align:start position:0% +so we take this Edge we turn it 90° what +we get is a on the left B on the right + + align:start position:0% +we get is a on the left B on the right + + + align:start position:0% +we get is a on the left B on the right +still should preserve the in order + + align:start position:0% +still should preserve the in order + + + align:start position:0% +still should preserve the in order +traversal C up top still we have the Y + + align:start position:0% +traversal C up top still we have the Y + + + align:start position:0% +traversal C up top still we have the Y +sub tree hanging off as + + align:start position:0% +sub tree hanging off as + + + align:start position:0% +sub tree hanging off as +before uh we have one of the sub trees + + align:start position:0% +before uh we have one of the sub trees + + + align:start position:0% +before uh we have one of the sub trees +one of the other three sub trees hanging + + align:start position:0% +one of the other three sub trees hanging + + + align:start position:0% +one of the other three sub trees hanging +off B and the other two now hang off a + + align:start position:0% +off B and the other two now hang off a + + + align:start position:0% +off B and the other two now hang off a +so this was just a generic rotation + + align:start position:0% +so this was just a generic rotation + + + align:start position:0% +so this was just a generic rotation +picture applied to this + + align:start position:0% +picture applied to this + + + align:start position:0% +picture applied to this +Edge okay what that does is before we + + align:start position:0% +Edge okay what that does is before we + + + align:start position:0% +Edge okay what that does is before we +had a zigzag between X and its + + align:start position:0% +had a zigzag between X and its + + + align:start position:0% +had a zigzag between X and its +grandparent now we have a zig Zig we + + align:start position:0% +grandparent now we have a zig Zig we + + + align:start position:0% +grandparent now we have a zig Zig we +have a straight path between X so X is + + align:start position:0% +have a straight path between X so X is + + + align:start position:0% +have a straight path between X so X is +still down here I'm not changing X in + + align:start position:0% +still down here I'm not changing X in + + + align:start position:0% +still down here I'm not changing X in +this case because uh after I do case two + + align:start position:0% +this case because uh after I do case two + + + align:start position:0% +this case because uh after I do case two +I immediately do case three so this is + + align:start position:0% +I immediately do case three so this is + + + align:start position:0% +I immediately do case three so this is +what case three will look like and now I + + align:start position:0% +what case three will look like and now I + + + align:start position:0% +what case three will look like and now I +continue on to case three + + align:start position:0% + + + + align:start position:0% + +so finally here's case three and this + + align:start position:0% +so finally here's case three and this + + + align:start position:0% +so finally here's case three and this +will finally complete the insertion + + align:start position:0% +will finally complete the insertion + + + align:start position:0% +will finally complete the insertion +algorithm we have a black node C we have + + align:start position:0% +algorithm we have a black node C we have + + + align:start position:0% +algorithm we have a black node C we have +a red left child from C we have a red + + align:start position:0% +a red left child from C we have a red + + + align:start position:0% +a red left child from C we have a red +left grandchild which is + + align:start position:0% +left grandchild which is + + + align:start position:0% +left grandchild which is +X and then we have these black subt + + align:start position:0% +X and then we have these black subt + + + align:start position:0% +X and then we have these black subt +trees all of the same black height + + align:start position:0% +trees all of the same black height + + + align:start position:0% +trees all of the same black height +hanging off + + align:start position:0% + + + + align:start position:0% + +okay which is exactly what we had at the + + align:start position:0% +okay which is exactly what we had at the + + + align:start position:0% +okay which is exactly what we had at the +end of case two so that definitely + + align:start position:0% +end of case two so that definitely + + + align:start position:0% +end of case two so that definitely +connects over and remember this is the + + align:start position:0% +connects over and remember this is the + + + align:start position:0% +connects over and remember this is the +only case left in category a category a + + align:start position:0% +only case left in category a category a + + + align:start position:0% +only case left in category a category a +we assumed that b was the you know the + + align:start position:0% +we assumed that b was the you know the + + + align:start position:0% +we assumed that b was the you know the +parent of X was the left child of the + + align:start position:0% +parent of X was the left child of the + + + align:start position:0% +parent of X was the left child of the +grandparent here c um so we know that we + + align:start position:0% +grandparent here c um so we know that we + + + align:start position:0% +grandparent here c um so we know that we +already did the case when y over here is + + align:start position:0% +already did the case when y over here is + + + align:start position:0% +already did the case when y over here is +red that was case one so we're assuming + + align:start position:0% +red that was case one so we're assuming + + + align:start position:0% +red that was case one so we're assuming +Y is black now we look at whether X was + + align:start position:0% +Y is black now we look at whether X was + + + align:start position:0% +Y is black now we look at whether X was +the left child or the right child if it + + align:start position:0% +the left child or the right child if it + + + align:start position:0% +the left child or the right child if it +was the right child we made it into the + + align:start position:0% +was the right child we made it into the + + + align:start position:0% +was the right child we made it into the +left child uh X actually did change here + + align:start position:0% +left child uh X actually did change here + + + align:start position:0% +left child uh X actually did change here +before X was B now X is + + align:start position:0% +before X was B now X is + + + align:start position:0% +before X was B now X is +a okay and then case three finally is + + align:start position:0% +a okay and then case three finally is + + + align:start position:0% +a okay and then case three finally is +when X is the left child of the parent + + align:start position:0% +when X is the left child of the parent + + + align:start position:0% +when X is the left child of the parent +who is the left child of the grandparent + + align:start position:0% +who is the left child of the grandparent + + + align:start position:0% +who is the left child of the grandparent +this is the last case we have to worry + + align:start position:0% + + + + align:start position:0% + +about + + align:start position:0% + + + + align:start position:0% + +and what we do is another rot rotation + + align:start position:0% +and what we do is another rot rotation + + + align:start position:0% +and what we do is another rot rotation +just like the last rotation we did in + + align:start position:0% +just like the last rotation we did in + + + align:start position:0% +just like the last rotation we did in +the + + align:start position:0% +the + + + align:start position:0% +the +example that was case + + align:start position:0% +example that was case + + + align:start position:0% +example that was case +three so we're going to do a right + + align:start position:0% +three so we're going to do a right + + + align:start position:0% +three so we're going to do a right +rotate in this + + align:start position:0% + + + + align:start position:0% + +case + + align:start position:0% +case + + + align:start position:0% +case +of + + align:start position:0% +of + + + align:start position:0% +of +c and we're going to + + align:start position:0% + + + + align:start position:0% + +recolor + + align:start position:0% + + + + align:start position:0% + +Okay so + + align:start position:0% + + + + align:start position:0% + +what do we get well B now becomes the + + align:start position:0% +what do we get well B now becomes the + + + align:start position:0% +what do we get well B now becomes the +root and I'm going to make it black okay + + align:start position:0% +root and I'm going to make it black okay + + + align:start position:0% +root and I'm going to make it black okay +remember this this is the root of the + + align:start position:0% +remember this this is the root of the + + + align:start position:0% +remember this this is the root of the +sub tree there's other stuff hanging off + + align:start position:0% +sub tree there's other stuff hanging off + + + align:start position:0% +sub tree there's other stuff hanging off +here I really should have drawn extra + + align:start position:0% +here I really should have drawn extra + + + align:start position:0% +here I really should have drawn extra +parents in all of these pictures + + align:start position:0% +parents in all of these pictures + + + align:start position:0% +parents in all of these pictures +somewhere in the middle of the tree + + align:start position:0% +somewhere in the middle of the tree + + + align:start position:0% +somewhere in the middle of the tree +don't know where could be a rightward + + align:start position:0% +don't know where could be a rightward + + + align:start position:0% +don't know where could be a rightward +branch could be a leftward branch we + + align:start position:0% +branch could be a leftward branch we + + + align:start position:0% +branch could be a leftward branch we +don't know C becomes the child of B and + + align:start position:0% +don't know C becomes the child of B and + + + align:start position:0% +don't know C becomes the child of B and +I'm going to make it a red child a + + align:start position:0% +I'm going to make it a red child a + + + align:start position:0% +I'm going to make it a red child a +becomes a child of b as it was before + + align:start position:0% +becomes a child of b as it was before + + + align:start position:0% +becomes a child of b as it was before +keep it red + + align:start position:0% + + + + align:start position:0% + +and everything else just hangs + + align:start position:0% +and everything else just hangs + + + align:start position:0% +and everything else just hangs +off so there were + + align:start position:0% +off so there were + + + align:start position:0% +off so there were +four subtes all with the same black + + align:start position:0% +four subtes all with the same black + + + align:start position:0% +four subtes all with the same black +height and in particular this last one + + align:start position:0% +height and in particular this last one + + + align:start position:0% +height and in particular this last one +had y but we don't particularly care + + align:start position:0% +had y but we don't particularly care + + + align:start position:0% +had y but we don't particularly care +about y + + align:start position:0% +about y + + + align:start position:0% +about y +anymore now we're in really good shape + + align:start position:0% +anymore now we're in really good shape + + + align:start position:0% +anymore now we're in really good shape +because we should have no more + + align:start position:0% +because we should have no more + + + align:start position:0% +because we should have no more +violations okay before we had a + + align:start position:0% +violations okay before we had a + + + align:start position:0% +violations okay before we had a +violation between X and its parent A and + + align:start position:0% +violation between X and its parent A and + + + align:start position:0% +violation between X and its parent A and +B those aren't even uh well A and B have + + align:start position:0% +B those aren't even uh well A and B have + + + align:start position:0% +B those aren't even uh well A and B have +still have a parent child relation but B + + align:start position:0% +still have a parent child relation but B + + + align:start position:0% +still have a parent child relation but B +is now black so and B is black so we + + align:start position:0% +is now black so and B is black so we + + + align:start position:0% +is now black so and B is black so we +don't care what its parent looks like + + align:start position:0% +don't care what its parent looks like + + + align:start position:0% +don't care what its parent looks like +could be red or black both are fine + + align:start position:0% +could be red or black both are fine + + + align:start position:0% +could be red or black both are fine +we're no longer violating property 3 we + + align:start position:0% +we're no longer violating property 3 we + + + align:start position:0% +we're no longer violating property 3 we +should be done in this + + align:start position:0% +should be done in this + + + align:start position:0% +should be done in this +case see property 3 is now + + align:start position:0% + + + + align:start position:0% + +true if you want you can say well X + + align:start position:0% +true if you want you can say well X + + + align:start position:0% +true if you want you can say well X +becomes this node and then the loop says + + align:start position:0% +becomes this node and then the loop says + + + align:start position:0% +becomes this node and then the loop says +oh X is no longer red therefore I'm done + + align:start position:0% +oh X is no longer red therefore I'm done + + + align:start position:0% +oh X is no longer red therefore I'm done +we also need to check that property 4 is + + align:start position:0% +we also need to check that property 4 is + + + align:start position:0% +we also need to check that property 4 is +preserved during this process again it's + + align:start position:0% +preserved during this process again it's + + + align:start position:0% +preserved during this process again it's +not hard because of the 234 tree + + align:start position:0% +not hard because of the 234 tree + + + align:start position:0% +not hard because of the 234 tree +transformation if I contract all the red + + align:start position:0% +transformation if I contract all the red + + + align:start position:0% +transformation if I contract all the red +things into their parents um everything + + align:start position:0% +things into their parents um everything + + + align:start position:0% +things into their parents um everything +else has a constant I mean every path in + + align:start position:0% +else has a constant I mean every path in + + + align:start position:0% +else has a constant I mean every path in +that tree and look has the same length + + align:start position:0% +that tree and look has the same length + + + align:start position:0% +that tree and look has the same length +because they have the same black length + + align:start position:0% +because they have the same black length + + + align:start position:0% +because they have the same black length +and over here that will still be true + + align:start position:0% +and over here that will still be true + + + align:start position:0% +and over here that will still be true +we're doing it's a little bit trickier + + align:start position:0% +we're doing it's a little bit trickier + + + align:start position:0% +we're doing it's a little bit trickier +here because we're recoloring at the + + align:start position:0% +here because we're recoloring at the + + + align:start position:0% +here because we're recoloring at the +same time but if you look at a path that + + align:start position:0% +same time but if you look at a path that + + + align:start position:0% +same time but if you look at a path that +comes through this tree it used to go + + align:start position:0% +comes through this tree it used to go + + + align:start position:0% +comes through this tree it used to go +through a black node C and then maybe + + align:start position:0% +through a black node C and then maybe + + + align:start position:0% +through a black node C and then maybe +some red stuff but I don't care and then + + align:start position:0% +some red stuff but I don't care and then + + + align:start position:0% +some red stuff but I don't care and then +it went through these trees which all + + align:start position:0% +it went through these trees which all + + + align:start position:0% +it went through these trees which all +have the same black height so they're + + align:start position:0% +have the same black height so they're + + + align:start position:0% +have the same black height so they're +all the same now you come in and you go + + align:start position:0% +all the same now you come in and you go + + + align:start position:0% +all the same now you come in and you go +through a black node called B and then + + align:start position:0% +through a black node called B and then + + + align:start position:0% +through a black node called B and then +you go through some red nodes doesn't + + align:start position:0% +you go through some red nodes doesn't + + + align:start position:0% +you go through some red nodes doesn't +really matter but all the trees that you + + align:start position:0% +really matter but all the trees that you + + + align:start position:0% +really matter but all the trees that you +go through down here have the same black + + align:start position:0% +go through down here have the same black + + + align:start position:0% +go through down here have the same black +height so every path through this tree + + align:start position:0% +height so every path through this tree + + + align:start position:0% +height so every path through this tree +will have the same black length Okay if + + align:start position:0% +will have the same black length Okay if + + + align:start position:0% +will have the same black length Okay if +it starts from the same + + align:start position:0% +it starts from the same + + + align:start position:0% +it starts from the same +node so we preserve property 4 we fix + + align:start position:0% +node so we preserve property 4 we fix + + + align:start position:0% +node so we preserve property 4 we fix +property three that is the insertion + + align:start position:0% +property three that is the insertion + + + align:start position:0% +property three that is the insertion +algorithm + + align:start position:0% +algorithm + + + align:start position:0% +algorithm +it's pretty + + align:start position:0% +it's pretty + + + align:start position:0% +it's pretty +long um this is something you'll + + align:start position:0% +long um this is something you'll + + + align:start position:0% +long um this is something you'll +probably just have to memorize it you've + + align:start position:0% +probably just have to memorize it you've + + + align:start position:0% +probably just have to memorize it you've +try a few examples is not so hard we can + + align:start position:0% +try a few examples is not so hard we can + + + align:start position:0% +try a few examples is not so hard we can +see that all the things we did in this + + align:start position:0% +see that all the things we did in this + + + align:start position:0% +see that all the things we did in this +example were the three cases the first + + align:start position:0% +example were the three cases the first + + + align:start position:0% +example were the three cases the first +step which unfortunately I had to erase + + align:start position:0% +step which unfortunately I had to erase + + + align:start position:0% +step which unfortunately I had to erase +for space uh all we did was recolor we + + align:start position:0% +for space uh all we did was recolor we + + + align:start position:0% +for space uh all we did was recolor we +recolored 10 and 8 and 11 that was a + + align:start position:0% +recolored 10 and 8 and 11 that was a + + + align:start position:0% +recolored 10 and 8 and 11 that was a +case one 10 was the grandparent of + + align:start position:0% +case one 10 was the grandparent of + + + align:start position:0% +case one 10 was the grandparent of +15 then we did then we looked at 10 10 + + align:start position:0% +15 then we did then we looked at 10 10 + + + align:start position:0% +15 then we did then we looked at 10 10 +was the Violator it was a zigzag case + + align:start position:0% +was the Violator it was a zigzag case + + + align:start position:0% +was the Violator it was a zigzag case +relative to its grandparent so we did a + + align:start position:0% +relative to its grandparent so we did a + + + align:start position:0% +relative to its grandparent so we did a +right rotation to fix that took this + + align:start position:0% +right rotation to fix that took this + + + align:start position:0% +right rotation to fix that took this +Edge and turned it so that 10 became + + align:start position:0% +Edge and turned it so that 10 became + + + align:start position:0% +Edge and turned it so that 10 became +next to seven that's the picture on the + + align:start position:0% +next to seven that's the picture on the + + + align:start position:0% +next to seven that's the picture on the +top then 18 which is the new violator + + align:start position:0% +top then 18 which is the new violator + + + align:start position:0% +top then 18 which is the new violator +with its grandparent is a zig Zig it's + + align:start position:0% +with its grandparent is a zig Zig it's + + + align:start position:0% +with its grandparent is a zig Zig it's +they're both going in the same + + align:start position:0% +they're both going in the same + + + align:start position:0% +they're both going in the same +direction and now we do one more + + align:start position:0% +direction and now we do one more + + + align:start position:0% +direction and now we do one more +rotation to fix that that's that's + + align:start position:0% +rotation to fix that that's that's + + + align:start position:0% +rotation to fix that that's that's +really the only thing you have to + + align:start position:0% +really the only thing you have to + + + align:start position:0% +really the only thing you have to +remember recolor your grandparent if you + + align:start position:0% +remember recolor your grandparent if you + + + align:start position:0% +remember recolor your grandparent if you +can otherwise make it Zig Zig and then + + align:start position:0% +can otherwise make it Zig Zig and then + + + align:start position:0% +can otherwise make it Zig Zig and then +do one more one last rotation and + + align:start position:0% +do one more one last rotation and + + + align:start position:0% +do one more one last rotation and +recolor and that will work I mean if you + + align:start position:0% +recolor and that will work I mean if you + + + align:start position:0% +recolor and that will work I mean if you +remember that you can figure out the + + align:start position:0% +remember that you can figure out the + + + align:start position:0% +remember that you can figure out the +rest on any particular example we rotate + + align:start position:0% +rest on any particular example we rotate + + + align:start position:0% +rest on any particular example we rotate +10 over that better be black because in + + align:start position:0% +10 over that better be black because in + + + align:start position:0% +10 over that better be black because in +this case it's becoming the root but + + align:start position:0% +this case it's becoming the root but + + + align:start position:0% +this case it's becoming the root but +we'll make it black no matter what + + align:start position:0% +we'll make it black no matter what + + + align:start position:0% +we'll make it black no matter what +happens because there has to be one + + align:start position:0% +happens because there has to be one + + + align:start position:0% +happens because there has to be one +black node there um if we didn't recolor + + align:start position:0% +black node there um if we didn't recolor + + + align:start position:0% +black node there um if we didn't recolor +at the same time we would violate + + align:start position:0% +at the same time we would violate + + + align:start position:0% +at the same time we would violate +property + + align:start position:0% +property + + + align:start position:0% +property + + align:start position:0% + + + align:start position:0% +um why don't I draw That Just for kicks + + align:start position:0% +um why don't I draw That Just for kicks + + + align:start position:0% +um why don't I draw That Just for kicks +and because I have a couple + + align:start position:0% +and because I have a couple + + + align:start position:0% +and because I have a couple +minutes so if we just did the rotation + + align:start position:0% +minutes so if we just did the rotation + + + align:start position:0% +minutes so if we just did the rotation +here + + align:start position:0% +here + + + align:start position:0% +here +so I say not the + + align:start position:0% +so I say not the + + + align:start position:0% +so I say not the +following we take b b is red this will + + align:start position:0% +following we take b b is red this will + + + align:start position:0% +following we take b b is red this will +give some intuition of why the algorithm + + align:start position:0% +give some intuition of why the algorithm + + + align:start position:0% +give some intuition of why the algorithm +was this way and not some other way um + + align:start position:0% +was this way and not some other way um + + + align:start position:0% +was this way and not some other way um +and C is black that's what we would have + + align:start position:0% +and C is black that's what we would have + + + align:start position:0% +and C is black that's what we would have +gotten if we just rotated this tree + + align:start position:0% +gotten if we just rotated this tree + + + align:start position:0% +gotten if we just rotated this tree +rotated b or rotated C to the right so + + align:start position:0% +rotated b or rotated C to the right so + + + align:start position:0% +rotated b or rotated C to the right so +these sub trees hang off in the same way + + align:start position:0% +these sub trees hang off in the same way + + + align:start position:0% +these sub trees hang off in the same way +sub trees look great because they all + + align:start position:0% +sub trees look great because they all + + + align:start position:0% +sub trees look great because they all +have the same black height but you see + + align:start position:0% +have the same black height but you see + + + align:start position:0% +have the same black height but you see +there's a problem if we look at all the + + align:start position:0% +there's a problem if we look at all the + + + align:start position:0% +there's a problem if we look at all the +paths starting from B and going down to + + align:start position:0% +paths starting from B and going down to + + + align:start position:0% +paths starting from B and going down to +a leaf on the left they H the number of + + align:start position:0% +a leaf on the left they H the number of + + + align:start position:0% +a leaf on the left they H the number of +black nodes is whatever the black height + + align:start position:0% +black nodes is whatever the black height + + + align:start position:0% +black nodes is whatever the black height +is over + + align:start position:0% +is over + + + align:start position:0% +is over +here label that black height um whereas + + align:start position:0% +here label that black height um whereas + + + align:start position:0% +here label that black height um whereas +all the paths on the right will be that + + align:start position:0% +all the paths on the right will be that + + + align:start position:0% +all the paths on the right will be that +black height plus one because C is black + + align:start position:0% +black height plus one because C is black + + + align:start position:0% +black height plus one because C is black +so now we violated property + + align:start position:0% + + + + align:start position:0% + +four so we don't do this in case three + + align:start position:0% +four so we don't do this in case three + + + align:start position:0% +four so we don't do this in case three +we we after we do the rotation we also + + align:start position:0% +we we after we do the rotation we also + + + align:start position:0% +we we after we do the rotation we also +do a recoloring so we get this in other + + align:start position:0% +do a recoloring so we get this in other + + + align:start position:0% +do a recoloring so we get this in other +words we're putting the black node at + + align:start position:0% +words we're putting the black node at + + + align:start position:0% +words we're putting the black node at +the top cuz then every path has to go + + align:start position:0% +the top cuz then every path has to go + + + align:start position:0% +the top cuz then every path has to go +through that node whereas over here some + + align:start position:0% +through that node whereas over here some + + + align:start position:0% +through that node whereas over here some +of the noes went through C some of them + + align:start position:0% +of the noes went through C some of them + + + align:start position:0% +of the noes went through C some of them +went through a so this is + + align:start position:0% +went through a so this is + + + align:start position:0% +went through a so this is +bad right also we would have violated + + align:start position:0% +bad right also we would have violated + + + align:start position:0% +bad right also we would have violated +property three but the really bad thing + + align:start position:0% +property three but the really bad thing + + + align:start position:0% +property three but the really bad thing +is we're violating property 4 over + + align:start position:0% +is we're violating property 4 over + + + align:start position:0% +is we're violating property 4 over +here okay let me sum up a little bit + + align:start position:0% + + + + align:start position:0% + +so we've seen if we insert into a red + + align:start position:0% +so we've seen if we insert into a red + + + align:start position:0% +so we've seen if we insert into a red +black tree we can keep it a red black + + align:start position:0% + + + + align:start position:0% + +tree so RB + + align:start position:0% + + + + align:start position:0% + +insert adds x to the + + align:start position:0% + + + + align:start position:0% + +set to the dynamic set that we're trying + + align:start position:0% +set to the dynamic set that we're trying + + + align:start position:0% +set to the dynamic set that we're trying +to maintain and + + align:start position:0% +to maintain and + + + align:start position:0% +to maintain and +preserves red blackness + + align:start position:0% + + + + align:start position:0% + +so keeps the tree a red black tree which + + align:start position:0% +so keeps the tree a red black tree which + + + align:start position:0% +so keeps the tree a red black tree which +is good because that means we know then + + align:start position:0% +is good because that means we know then + + + align:start position:0% +is good because that means we know then +that it keeps logarithmic height + + align:start position:0% +that it keeps logarithmic height + + + align:start position:0% +that it keeps logarithmic height +therefore all queries and red black + + align:start position:0% +therefore all queries and red black + + + align:start position:0% +therefore all queries and red black +trees will keep taking logarithmic time + + align:start position:0% +trees will keep taking logarithmic time + + + align:start position:0% +trees will keep taking logarithmic time +how long does red black insert + + align:start position:0% + + + + align:start position:0% + +take we know we're aiming for and for + + align:start position:0% +take we know we're aiming for and for + + + align:start position:0% +take we know we're aiming for and for +log n time per + + align:start position:0% +log n time per + + + align:start position:0% +log n time per +operation I'm not going to prove that + + align:start position:0% +operation I'm not going to prove that + + + align:start position:0% +operation I'm not going to prove that +formally but it should be pretty + + align:start position:0% +formally but it should be pretty + + + align:start position:0% +formally but it should be pretty +intuitive so cases two and three sorry + + align:start position:0% +intuitive so cases two and three sorry + + + align:start position:0% +intuitive so cases two and three sorry +pointing it the wrong place cases two + + align:start position:0% +pointing it the wrong place cases two + + + align:start position:0% +pointing it the wrong place cases two +and three are terminal when we do case + + align:start position:0% +and three are terminal when we do case + + + align:start position:0% +and three are terminal when we do case +three we're done when we do case two + + align:start position:0% +three we're done when we do case two + + + align:start position:0% +three we're done when we do case two +we're about to do case three and then + + align:start position:0% +we're about to do case three and then + + + align:start position:0% +we're about to do case three and then +we're done okay so the only thing we + + align:start position:0% +we're done okay so the only thing we + + + align:start position:0% +we're done okay so the only thing we +really have to count is case one because + + align:start position:0% +really have to count is case one because + + + align:start position:0% +really have to count is case one because +each of these operations you know + + align:start position:0% +each of these operations you know + + + align:start position:0% +each of these operations you know +recoloring rotation they all take + + align:start position:0% +recoloring rotation they all take + + + align:start position:0% +recoloring rotation they all take +constant time so it's a matter of how + + align:start position:0% +constant time so it's a matter of how + + + align:start position:0% +constant time so it's a matter of how +many are + + align:start position:0% +many are + + + align:start position:0% +many are +there uh case one does some recoloring + + align:start position:0% +there uh case one does some recoloring + + + align:start position:0% +there uh case one does some recoloring +doesn't change the tree at all + + align:start position:0% +doesn't change the tree at all + + + align:start position:0% +doesn't change the tree at all +and moves X up by two levels we know + + align:start position:0% +and moves X up by two levels we know + + + align:start position:0% +and moves X up by two levels we know +that the height of the tree is at most 2 + + align:start position:0% +that the height of the tree is at most 2 + + + align:start position:0% +that the height of the tree is at most 2 +log n + 1 so the number of case ones is + + align:start position:0% +log n + 1 so the number of case ones is + + + align:start position:0% +log n + 1 so the number of case ones is +at most log n + + + align:start position:0% +at most log n + + + + align:start position:0% +at most log n + +one okay so the number of case ones um + + align:start position:0% +one okay so the number of case ones um + + + align:start position:0% +one okay so the number of case ones um +it's at most log + + align:start position:0% + + + + align:start position:0% + +n so those take log n time and then the + + align:start position:0% +n so those take log n time and then the + + + align:start position:0% +n so those take log n time and then the +number of case twos and threes is at + + align:start position:0% +number of case twos and threes is at + + + align:start position:0% +number of case twos and threes is at +most one for one of these + + align:start position:0% +most one for one of these + + + align:start position:0% +most one for one of these +calls well together twos and threes is + + align:start position:0% +calls well together twos and threes is + + + align:start position:0% +calls well together twos and threes is +at most + + align:start position:0% +at most + + + align:start position:0% +at most +two okay so log n time cool uh the other + + align:start position:0% +two okay so log n time cool uh the other + + + align:start position:0% +two okay so log n time cool uh the other +thing that's interesting about red black + + align:start position:0% +thing that's interesting about red black + + + align:start position:0% +thing that's interesting about red black +insertion is that it only makes uh order + + align:start position:0% +insertion is that it only makes uh order + + + align:start position:0% +insertion is that it only makes uh order +one + + align:start position:0% +one + + + align:start position:0% +one +rotations so most of the changes are + + align:start position:0% + + + + align:start position:0% + +recoloring um the all case one just does + + align:start position:0% +recoloring um the all case one just does + + + align:start position:0% +recoloring um the all case one just does +recoloring no rotations case two maybe + + align:start position:0% +recoloring no rotations case two maybe + + + align:start position:0% +recoloring no rotations case two maybe +does one rotation case three does one + + align:start position:0% +does one rotation case three does one + + + align:start position:0% +does one rotation case three does one +rotation if you happen to be in those + + align:start position:0% +rotation if you happen to be in those + + + align:start position:0% +rotation if you happen to be in those +cases + + align:start position:0% +cases + + + align:start position:0% +cases +so the number of rotations is at most + + align:start position:0% +so the number of rotations is at most + + + align:start position:0% +so the number of rotations is at most +two it's either one or two in an + + align:start position:0% +two it's either one or two in an + + + align:start position:0% +two it's either one or two in an +insertion it's kind of nice because uh + + align:start position:0% +insertion it's kind of nice because uh + + + align:start position:0% +insertion it's kind of nice because uh +rotating a tree is a bit more annoying + + align:start position:0% +rotating a tree is a bit more annoying + + + align:start position:0% +rotating a tree is a bit more annoying +than + + align:start position:0% +than + + + align:start position:0% +than +uh than recoloring a tree why because if + + align:start position:0% +uh than recoloring a tree why because if + + + align:start position:0% +uh than recoloring a tree why because if +you have say uh a data structure you + + align:start position:0% +you have say uh a data structure you + + + align:start position:0% +you have say uh a data structure you +have a search tree you know presumably + + align:start position:0% +have a search tree you know presumably + + + align:start position:0% +have a search tree you know presumably +people are using the search tree for + + align:start position:0% +people are using the search tree for + + + align:start position:0% +people are using the search tree for +something they're like making queries + + align:start position:0% +something they're like making queries + + + align:start position:0% +something they're like making queries +for example this search tree represents + + align:start position:0% +for example this search tree represents + + + align:start position:0% +for example this search tree represents +I don't know all the documents matching + + align:start position:0% +I don't know all the documents matching + + + align:start position:0% +I don't know all the documents matching +the word computer in Google okay we got + + align:start position:0% +the word computer in Google okay we got + + + align:start position:0% +the word computer in Google okay we got +a Google t-shirt up here so let's use a + + align:start position:0% +a Google t-shirt up here so let's use a + + + align:start position:0% +a Google t-shirt up here so let's use a +Google reference you have this search + + align:start position:0% +Google reference you have this search + + + align:start position:0% +Google reference you have this search +Tree stores all the things containing + + align:start position:0% +Tree stores all the things containing + + + align:start position:0% +Tree stores all the things containing +the word Google you'd like to search + + align:start position:0% +the word Google you'd like to search + + + align:start position:0% +the word Google you'd like to search +maybe for the ones that were modified + + align:start position:0% +maybe for the ones that were modified + + + align:start position:0% +maybe for the ones that were modified +after a certain date or whatever it is + + align:start position:0% +after a certain date or whatever it is + + + align:start position:0% +after a certain date or whatever it is +you want to do so you're doing some + + align:start position:0% +you want to do so you're doing some + + + align:start position:0% +you want to do so you're doing some +queries on this tree and people are + + align:start position:0% +queries on this tree and people are + + + align:start position:0% +queries on this tree and people are +pummeling Google like crazy with queries + + align:start position:0% +pummeling Google like crazy with queries + + + align:start position:0% +pummeling Google like crazy with queries +you know they get a zillion in a second + + align:start position:0% +you know they get a zillion in a second + + + align:start position:0% +you know they get a zillion in a second +don't quote me on that the number may + + align:start position:0% +don't quote me on that the number may + + + align:start position:0% +don't quote me on that the number may +not be accurate it's a zillion but um + + align:start position:0% +not be accurate it's a zillion but um + + + align:start position:0% +not be accurate it's a zillion but um +people are making searches all the time + + align:start position:0% +people are making searches all the time + + + align:start position:0% +people are making searches all the time +if you recolor the tree people can still + + align:start position:0% +if you recolor the tree people can still + + + align:start position:0% +if you recolor the tree people can still +make searches that's just a little bit + + align:start position:0% +make searches that's just a little bit + + + align:start position:0% +make searches that's just a little bit +you're flipping I don't care in a search + + align:start position:0% +you're flipping I don't care in a search + + + align:start position:0% +you're flipping I don't care in a search +whether a note is red or black because I + + align:start position:0% +whether a note is red or black because I + + + align:start position:0% +whether a note is red or black because I +know it will have logarithmic height so + + align:start position:0% +know it will have logarithmic height so + + + align:start position:0% +know it will have logarithmic height so +you can come along and make your + + align:start position:0% +you can come along and make your + + + align:start position:0% +you can come along and make your +occasional updates as you as your + + align:start position:0% +occasional updates as you as your + + + align:start position:0% +occasional updates as you as your +crawler surfs the webs and finds changes + + align:start position:0% +crawler surfs the webs and finds changes + + + align:start position:0% +crawler surfs the webs and finds changes +and recoloring is great rotation is a + + align:start position:0% +and recoloring is great rotation is a + + + align:start position:0% +and recoloring is great rotation is a +bit expensive because you have to lock + + align:start position:0% +bit expensive because you have to lock + + + align:start position:0% +bit expensive because you have to lock +those nodes make sure no one touches + + align:start position:0% +those nodes make sure no one touches + + + align:start position:0% +those nodes make sure no one touches +them for the duration that you rotate + + align:start position:0% +them for the duration that you rotate + + + align:start position:0% +them for the duration that you rotate +them and then unlock them so it's nice + + align:start position:0% +them and then unlock them so it's nice + + + align:start position:0% +them and then unlock them so it's nice +that the number of rotations is small + + align:start position:0% +that the number of rotations is small + + + align:start position:0% +that the number of rotations is small +really small just two whereas the time + + align:start position:0% +really small just two whereas the time + + + align:start position:0% +really small just two whereas the time +has to be log n because we're inserting + + align:start position:0% +has to be log n because we're inserting + + + align:start position:0% +has to be log n because we're inserting +into a sorted list essentially so + + align:start position:0% +into a sorted list essentially so + + + align:start position:0% +into a sorted list essentially so +there's an N logn lower if we do n + + align:start position:0% +there's an N logn lower if we do n + + + align:start position:0% +there's an N logn lower if we do n +insertions okay deletion I'm not going + + align:start position:0% +insertions okay deletion I'm not going + + + align:start position:0% +insertions okay deletion I'm not going +to cover here you should read it in the + + align:start position:0% +to cover here you should read it in the + + + align:start position:0% +to cover here you should read it in the +book it's a little bit more complicated + + align:start position:0% +book it's a little bit more complicated + + + align:start position:0% +book it's a little bit more complicated +but the same ideas it gets the same + + align:start position:0% +but the same ideas it gets the same + + + align:start position:0% +but the same ideas it gets the same +bounds log and time order one + + align:start position:0% +bounds log and time order one + + + align:start position:0% +bounds log and time order one +rotations so check it out that's red + + align:start position:0% +rotations so check it out that's red + + + align:start position:0% +rotations so check it out that's red +black trees now you can maintain data in + + align:start position:0% +black trees now you can maintain data in + + + align:start position:0% +black trees now you can maintain data in +login time per operation + + align:start position:0% +login time per operation + + + align:start position:0% +login time per operation +cool we'll now see three ways to do it \ No newline at end of file diff --git a/OMFpHmfC1pY.txt b/OMFpHmfC1pY.txt new file mode 100644 index 0000000000000000000000000000000000000000..91c2cd171170854da0716eab9211b37427a4e0e6 --- /dev/null +++ b/OMFpHmfC1pY.txt @@ -0,0 +1,9611 @@ +align:start position:0% + +today + + align:start position:0% +today + + + align:start position:0% +today +we are talking about + + align:start position:0% +we are talking about + + + align:start position:0% +we are talking about +bonding between molecules + + align:start position:0% +bonding between molecules + + + align:start position:0% +bonding between molecules +now we have talked a lot about bonding + + align:start position:0% +now we have talked a lot about bonding + + + align:start position:0% +now we have talked a lot about bonding +within molecules + + align:start position:0% +within molecules + + + align:start position:0% +within molecules +right and that got us to saying things + + align:start position:0% +right and that got us to saying things + + + align:start position:0% +right and that got us to saying things +like well you can use electronegativity + + align:start position:0% +like well you can use electronegativity + + + align:start position:0% +like well you can use electronegativity +for example and say + + align:start position:0% +for example and say + + + align:start position:0% +for example and say +i got an ionic bond all right + + align:start position:0% +i got an ionic bond all right + + + align:start position:0% +i got an ionic bond all right +or i've got a nonpolar covalent bond or + + align:start position:0% +or i've got a nonpolar covalent bond or + + + align:start position:0% +or i've got a nonpolar covalent bond or +i've got a polar covalent bond but today + + align:start position:0% +i've got a polar covalent bond but today + + + align:start position:0% +i've got a polar covalent bond but today +what we're gonna do is talk about how + + align:start position:0% +what we're gonna do is talk about how + + + align:start position:0% +what we're gonna do is talk about how +these molecules how these molecules + + align:start position:0% +these molecules how these molecules + + + align:start position:0% +these molecules how these molecules +bond together what sorts of interactions + + align:start position:0% +bond together what sorts of interactions + + + align:start position:0% +bond together what sorts of interactions +can they have + + align:start position:0% +can they have + + + align:start position:0% +can they have +and those are really important right so + + align:start position:0% +and those are really important right so + + + align:start position:0% +and those are really important right so +so that's going to be the topic now if + + align:start position:0% +so that's going to be the topic now if + + + align:start position:0% +so that's going to be the topic now if +we just get started with what we know + + align:start position:0% +we just get started with what we know + + + align:start position:0% +we just get started with what we know +what's up there right well there's ionic + + align:start position:0% +what's up there right well there's ionic + + + align:start position:0% +what's up there right well there's ionic +so let's say + + align:start position:0% +so let's say + + + align:start position:0% +so let's say +i'm going to i'm going to fill this in + + align:start position:0% +i'm going to i'm going to fill this in + + + align:start position:0% +i'm going to i'm going to fill this in +bond + + align:start position:0% +bond + + + align:start position:0% +bond +a model you'll see what i mean i'm going + + align:start position:0% +a model you'll see what i mean i'm going + + + align:start position:0% +a model you'll see what i mean i'm going +to draw a little cartoon the + + align:start position:0% +to draw a little cartoon the + + + align:start position:0% +to draw a little cartoon the +attraction how it's attracted uh the + + align:start position:0% +attraction how it's attracted uh the + + + align:start position:0% +attraction how it's attracted uh the +energy range + + align:start position:0% +energy range + + + align:start position:0% +energy range +and an example right so for ionic bond + + align:start position:0% +and an example right so for ionic bond + + + align:start position:0% +and an example right so for ionic bond +we got ionic ionic + + align:start position:0% +we got ionic ionic + + + align:start position:0% +we got ionic ionic +okay and here we go watch this plus + + align:start position:0% +okay and here we go watch this plus + + + align:start position:0% +okay and here we go watch this plus +and minus there's my model + + align:start position:0% +and minus there's my model + + + align:start position:0% +and minus there's my model +okay and the attraction here well we'll + + align:start position:0% +okay and the attraction here well we'll + + + align:start position:0% +okay and the attraction here well we'll +get a little specific it's a cation + + align:start position:0% +get a little specific it's a cation + + + align:start position:0% +get a little specific it's a cation +and an anion and we know that that's + + align:start position:0% +and an anion and we know that that's + + + align:start position:0% +and an anion and we know that that's +gonna go like coulomb's law right so the + + align:start position:0% +gonna go like coulomb's law right so the + + + align:start position:0% +gonna go like coulomb's law right so the +attraction the energy + + align:start position:0% +attraction the energy + + + align:start position:0% +attraction the energy +not the force the energy will go like + + align:start position:0% +not the force the energy will go like + + + align:start position:0% +not the force the energy will go like +one over r + + align:start position:0% +one over r + + + align:start position:0% +one over r +roughly uh now what is the energy well + + align:start position:0% +roughly uh now what is the energy well + + + align:start position:0% +roughly uh now what is the energy well +the energy is pretty wide ranging it's + + align:start position:0% +the energy is pretty wide ranging it's + + + align:start position:0% +the energy is pretty wide ranging it's +i'm gonna do this in in kilojoules per + + align:start position:0% +i'm gonna do this in in kilojoules per + + + align:start position:0% +i'm gonna do this in in kilojoules per +mole since those are the units i have + + align:start position:0% +mole since those are the units i have + + + align:start position:0% +mole since those are the units i have +i'll write that in a second and + + align:start position:0% +i'll write that in a second and + + + align:start position:0% +i'll write that in a second and +an ionic bond can have lots and lots of + + align:start position:0% +an ionic bond can have lots and lots of + + + align:start position:0% +an ionic bond can have lots and lots of +range in here and it typically can be + + align:start position:0% +range in here and it typically can be + + + align:start position:0% +range in here and it typically can be +very strong + + align:start position:0% +very strong + + + align:start position:0% +very strong +something we've already talked about an + + align:start position:0% +something we've already talked about an + + + align:start position:0% +something we've already talked about an +example would be sodium chloride + + align:start position:0% +example would be sodium chloride + + + align:start position:0% +example would be sodium chloride +it's right there let's put the units + + align:start position:0% +it's right there let's put the units + + + align:start position:0% +it's right there let's put the units +here + + align:start position:0% +here + + + align:start position:0% +here +the energy units are in i'm going to + + align:start position:0% +the energy units are in i'm going to + + + align:start position:0% +the energy units are in i'm going to +write it here + + align:start position:0% +write it here + + + align:start position:0% +write it here +kilojoules per mole + + align:start position:0% +kilojoules per mole + + + align:start position:0% +kilojoules per mole +okay now in a covalent bond so covalent + + align:start position:0% +okay now in a covalent bond so covalent + + + align:start position:0% +okay now in a covalent bond so covalent +would be here + + align:start position:0% +would be here + + + align:start position:0% +would be here +okay so in a covalent bond remember + + align:start position:0% +okay so in a covalent bond remember + + + align:start position:0% +okay so in a covalent bond remember +we've got something very different we've + + align:start position:0% +we've got something very different we've + + + align:start position:0% +we've got something very different we've +got this carrying and sharing kind of + + align:start position:0% +got this carrying and sharing kind of + + + align:start position:0% +got this carrying and sharing kind of +thing + + align:start position:0% +thing + + + align:start position:0% +thing +and we've got maybe two atoms right two + + align:start position:0% +and we've got maybe two atoms right two + + + align:start position:0% +and we've got maybe two atoms right two +atoms like this + + align:start position:0% +atoms like this + + + align:start position:0% +atoms like this +and then the charge is sort of you know + + align:start position:0% +and then the charge is sort of you know + + + align:start position:0% +and then the charge is sort of you know +the negative charge is sort of floating + + align:start position:0% +the negative charge is sort of floating + + + align:start position:0% +the negative charge is sort of floating +around and sharing + + align:start position:0% +around and sharing + + + align:start position:0% +around and sharing +those two centers like in h2 + + align:start position:0% +those two centers like in h2 + + + align:start position:0% +those two centers like in h2 +or cl2 i'm going to use cl so let's keep + + align:start position:0% +or cl2 i'm going to use cl so let's keep + + + align:start position:0% +or cl2 i'm going to use cl so let's keep +using cl + + align:start position:0% +using cl + + + align:start position:0% +using cl +right that would also be an example of a + + align:start position:0% +right that would also be an example of a + + + align:start position:0% +right that would also be an example of a +covalent bond + + align:start position:0% +covalent bond + + + align:start position:0% +covalent bond +and the energy range there is also quite + + align:start position:0% +and the energy range there is also quite + + + align:start position:0% +and the energy range there is also quite +large 150 + + align:start position:0% +large 150 + + + align:start position:0% +large 150 +to 1100 are the numbers i got the + + align:start position:0% +to 1100 are the numbers i got the + + + align:start position:0% +to 1100 are the numbers i got the +attraction is shared electrons + + align:start position:0% +attraction is shared electrons + + + align:start position:0% +attraction is shared electrons +shared pair + + align:start position:0% +shared pair + + + align:start position:0% +shared pair +of electrons and + + align:start position:0% +of electrons and + + + align:start position:0% +of electrons and +i'm not putting an r dependence because + + align:start position:0% +i'm not putting an r dependence because + + + align:start position:0% +i'm not putting an r dependence because +for a covalent bond it's complicated + + align:start position:0% +for a covalent bond it's complicated + + + align:start position:0% +for a covalent bond it's complicated +it's complicated there's no it is it is + + align:start position:0% +it's complicated there's no it is it is + + + align:start position:0% +it's complicated there's no it is it is +it's a complicated but it's a very nice + + align:start position:0% +it's a complicated but it's a very nice + + + align:start position:0% +it's a complicated but it's a very nice +happy relationship but it's a + + align:start position:0% +happy relationship but it's a + + + align:start position:0% +happy relationship but it's a +complicated r + + align:start position:0% +complicated r + + + align:start position:0% +complicated r +dependence so you can't simplify it like + + align:start position:0% +dependence so you can't simplify it like + + + align:start position:0% +dependence so you can't simplify it like +you can + + align:start position:0% +you can + + + align:start position:0% +you can +with a one over r or like some of the + + align:start position:0% +with a one over r or like some of the + + + align:start position:0% +with a one over r or like some of the +other interactions we'll talk about + + align:start position:0% +other interactions we'll talk about + + + align:start position:0% +other interactions we'll talk about +today + + align:start position:0% +today + + + align:start position:0% +today +okay one over r not for covalent + + align:start position:0% +okay one over r not for covalent + + + align:start position:0% +okay one over r not for covalent +all right now that's where we've been um + + align:start position:0% + + + + align:start position:0% + +here we go here we go look at this + + align:start position:0% +here we go here we go look at this + + + align:start position:0% +here we go here we go look at this +i'm not i'm just getting started because + + align:start position:0% +i'm not i'm just getting started because + + + align:start position:0% +i'm not i'm just getting started because +the thing is + + align:start position:0% +the thing is + + + align:start position:0% +the thing is +now we got to talk about how these + + align:start position:0% +now we got to talk about how these + + + align:start position:0% +now we got to talk about how these +molecules can talk to each other + + align:start position:0% +molecules can talk to each other + + + align:start position:0% +molecules can talk to each other +and there's a variety of ways what i + + align:start position:0% +and there's a variety of ways what i + + + align:start position:0% +and there's a variety of ways what i +want to focus on + + align:start position:0% +want to focus on + + + align:start position:0% +want to focus on +first is this thing here that's that + + align:start position:0% +first is this thing here that's that + + + align:start position:0% +first is this thing here that's that +polar covalent bond + + align:start position:0% +polar covalent bond + + + align:start position:0% +polar covalent bond +that we've already talked about so we've + + align:start position:0% +that we've already talked about so we've + + + align:start position:0% +that we've already talked about so we've +already got a grounding for it right + + align:start position:0% +already got a grounding for it right + + + align:start position:0% +already got a grounding for it right +but i want to remind you of what happens + + align:start position:0% +but i want to remind you of what happens + + + align:start position:0% +but i want to remind you of what happens +right so if i have + + align:start position:0% +right so if i have + + + align:start position:0% +right so if i have +let's keep with hcl if i have hcl + + align:start position:0% +let's keep with hcl if i have hcl + + + align:start position:0% +let's keep with hcl if i have hcl +that's a nice version of a polar + + align:start position:0% +that's a nice version of a polar + + + align:start position:0% +that's a nice version of a polar +covalent bond + + align:start position:0% +covalent bond + + + align:start position:0% +covalent bond +and remember what happens there is you + + align:start position:0% +and remember what happens there is you + + + align:start position:0% +and remember what happens there is you +you got + + align:start position:0% +you got + + + align:start position:0% +you got +a sharing but sort of unfair right so + + align:start position:0% +a sharing but sort of unfair right so + + + align:start position:0% +a sharing but sort of unfair right so +one of the atoms took a little more + + align:start position:0% +one of the atoms took a little more + + + align:start position:0% +one of the atoms took a little more +of the charge and so sometimes we + + align:start position:0% +of the charge and so sometimes we + + + align:start position:0% +of the charge and so sometimes we +you know represent that with like a more + + align:start position:0% +you know represent that with like a more + + + align:start position:0% +you know represent that with like a more +of the cloud + + align:start position:0% +of the cloud + + + align:start position:0% +of the cloud +right on one side than the other but + + align:start position:0% +right on one side than the other but + + + align:start position:0% +right on one side than the other but +it's still a covalent bond + + align:start position:0% +it's still a covalent bond + + + align:start position:0% +it's still a covalent bond +yeah but the thing is that and and so + + align:start position:0% +yeah but the thing is that and and so + + + align:start position:0% +yeah but the thing is that and and so +what you're left with like in this case + + align:start position:0% +what you're left with like in this case + + + align:start position:0% +what you're left with like in this case +is some positive charge on the hydrogen + + align:start position:0% +is some positive charge on the hydrogen + + + align:start position:0% +is some positive charge on the hydrogen +atom + + align:start position:0% +atom + + + align:start position:0% +atom +and some negative charge on the chlorine + + align:start position:0% +and some negative charge on the chlorine + + + align:start position:0% +and some negative charge on the chlorine +atom and we did this already we used + + align:start position:0% +atom and we did this already we used + + + align:start position:0% +atom and we did this already we used +these symbols + + align:start position:0% +these symbols + + + align:start position:0% +these symbols +and we also talked about how that leads + + align:start position:0% +and we also talked about how that leads + + + align:start position:0% +and we also talked about how that leads +you to + + align:start position:0% +you to + + + align:start position:0% +you to +a dipole moment + + align:start position:0% + + + + align:start position:0% + +now what is a dipole well a dipole is + + align:start position:0% +now what is a dipole well a dipole is + + + align:start position:0% +now what is a dipole well a dipole is +just + + align:start position:0% +just + + + align:start position:0% +just +the is is just the the description of + + align:start position:0% +the is is just the the description of + + + align:start position:0% +the is is just the the description of +what you have in this case where you've + + align:start position:0% +what you have in this case where you've + + + align:start position:0% +what you have in this case where you've +got + + align:start position:0% +got + + + align:start position:0% +got +two charges of opposite signs + + align:start position:0% +two charges of opposite signs + + + align:start position:0% +two charges of opposite signs +separated by some distance okay + + align:start position:0% +separated by some distance okay + + + align:start position:0% +separated by some distance okay +two charges those aren't full charges + + align:start position:0% +two charges those aren't full charges + + + align:start position:0% +two charges those aren't full charges +those are partial charges + + align:start position:0% +those are partial charges + + + align:start position:0% +those are partial charges +right they're separated by some distance + + align:start position:0% +right they're separated by some distance + + + align:start position:0% +right they're separated by some distance +the distance between these two atoms + + align:start position:0% +the distance between these two atoms + + + align:start position:0% +the distance between these two atoms +and you get a dipole moment and it has a + + align:start position:0% +and you get a dipole moment and it has a + + + align:start position:0% +and you get a dipole moment and it has a +magnitude + + align:start position:0% +magnitude + + + align:start position:0% +magnitude +and a direction and remember + + align:start position:0% +and a direction and remember + + + align:start position:0% +and a direction and remember +just so that just to remind you i did + + align:start position:0% +just so that just to remind you i did + + + align:start position:0% +just so that just to remind you i did +share this with you in a previous + + align:start position:0% +share this with you in a previous + + + align:start position:0% +share this with you in a previous +lecture but you know mu + + align:start position:0% +lecture but you know mu + + + align:start position:0% +lecture but you know mu +equals the charge times the distance + + align:start position:0% +equals the charge times the distance + + + align:start position:0% +equals the charge times the distance +between the charge + + align:start position:0% +between the charge + + + align:start position:0% +between the charge +right so that would be like the charge + + align:start position:0% +right so that would be like the charge + + + align:start position:0% +right so that would be like the charge +would be the deltas here and the + + align:start position:0% +would be the deltas here and the + + + align:start position:0% +would be the deltas here and the +distance between them + + align:start position:0% +distance between them + + + align:start position:0% +distance between them +right would be this right r um and i + + align:start position:0% +right would be this right r um and i + + + align:start position:0% +right would be this right r um and i +also and now remember the units are in + + align:start position:0% +also and now remember the units are in + + + align:start position:0% +also and now remember the units are in +dubai + + align:start position:0% +dubai + + + align:start position:0% +dubai +so for this molecule for here + + align:start position:0% +so for this molecule for here + + + align:start position:0% +so for this molecule for here +mu is around 1.8 + + align:start position:0% +mu is around 1.8 + + + align:start position:0% +mu is around 1.8 +d and 1 d + + align:start position:0% +d and 1 d + + + align:start position:0% +d and 1 d +is equal to 3.3 + + align:start position:0% +is equal to 3.3 + + + align:start position:0% +is equal to 3.3 +times 10 to the minus 30th + + align:start position:0% +times 10 to the minus 30th + + + align:start position:0% +times 10 to the minus 30th +coulomb meters those are the units + + align:start position:0% +coulomb meters those are the units + + + align:start position:0% +coulomb meters those are the units +charge times distance charge times + + align:start position:0% +charge times distance charge times + + + align:start position:0% +charge times distance charge times +distance right + + align:start position:0% +distance right + + + align:start position:0% +distance right +okay 3.3 times to the minus thirds + + align:start position:0% +okay 3.3 times to the minus thirds + + + align:start position:0% +okay 3.3 times to the minus thirds +coolants per meter is a dubai + + align:start position:0% +coolants per meter is a dubai + + + align:start position:0% +coolants per meter is a dubai +and again just to remind you because we + + align:start position:0% +and again just to remind you because we + + + align:start position:0% +and again just to remind you because we +did talk about this when we talked about + + align:start position:0% +did talk about this when we talked about + + + align:start position:0% +did talk about this when we talked about +polar covalent bonds + + align:start position:0% +polar covalent bonds + + + align:start position:0% +polar covalent bonds +the dipole moment of these molecules + + align:start position:0% +the dipole moment of these molecules + + + align:start position:0% +the dipole moment of these molecules +tends to range + + align:start position:0% +tends to range + + + align:start position:0% +tends to range +from zero right there + + align:start position:0% +from zero right there + + + align:start position:0% +from zero right there +right no dipole to 10 or so + + align:start position:0% +right no dipole to 10 or so + + + align:start position:0% +right no dipole to 10 or so +11. right device + + align:start position:0% +11. right device + + + align:start position:0% +11. right device +now why is this important well because + + align:start position:0% +now why is this important well because + + + align:start position:0% +now why is this important well because +if you + + align:start position:0% +if you + + + align:start position:0% +if you +if you now think well what would happen + + align:start position:0% +if you now think well what would happen + + + align:start position:0% +if you now think well what would happen +what would happen if i brought another + + align:start position:0% +what would happen if i brought another + + + align:start position:0% +what would happen if i brought another +charge + + align:start position:0% +charge + + + align:start position:0% +charge +up to the dipole what would happen right + + align:start position:0% +up to the dipole what would happen right + + + align:start position:0% +up to the dipole what would happen right +let's say that i bring a positive charge + + align:start position:0% +let's say that i bring a positive charge + + + align:start position:0% +let's say that i bring a positive charge +let's say that i have + + align:start position:0% +let's say that i have + + + align:start position:0% +let's say that i have +that i'm a sodium and i've lost that + + align:start position:0% +that i'm a sodium and i've lost that + + + align:start position:0% +that i'm a sodium and i've lost that +outer electron which we know is pretty + + align:start position:0% +outer electron which we know is pretty + + + align:start position:0% +outer electron which we know is pretty +easy to lose + + align:start position:0% +easy to lose + + + align:start position:0% +easy to lose +if you're sodium right so i'm positively + + align:start position:0% +if you're sodium right so i'm positively + + + align:start position:0% +if you're sodium right so i'm positively +charged + + align:start position:0% +charged + + + align:start position:0% +charged +and i'm coming along and i see this + + align:start position:0% +and i'm coming along and i see this + + + align:start position:0% +and i'm coming along and i see this +dipole well it turns out + + align:start position:0% +dipole well it turns out + + + align:start position:0% +dipole well it turns out +that as you can imagine i'm going to be + + align:start position:0% +that as you can imagine i'm going to be + + + align:start position:0% +that as you can imagine i'm going to be +attracted to that negative charge + + align:start position:0% +attracted to that negative charge + + + align:start position:0% +attracted to that negative charge +right so this molecule is going to + + align:start position:0% +right so this molecule is going to + + + align:start position:0% +right so this molecule is going to +orient + + align:start position:0% +orient + + + align:start position:0% +orient +in such a way that that i can actually + + align:start position:0% +in such a way that that i can actually + + + align:start position:0% +in such a way that that i can actually +bond bond to the to the molecule + + align:start position:0% +bond bond to the to the molecule + + + align:start position:0% +bond bond to the to the molecule +and and be attracted to the dipole of + + align:start position:0% +and and be attracted to the dipole of + + + align:start position:0% +and and be attracted to the dipole of +the molecule so that is actually another + + align:start position:0% +the molecule so that is actually another + + + align:start position:0% +the molecule so that is actually another +type of bond + + align:start position:0% +type of bond + + + align:start position:0% +type of bond +right and we'll call that ion + + align:start position:0% +right and we'll call that ion + + + align:start position:0% +right and we'll call that ion +dipole it's an ion dipole bond + + align:start position:0% +dipole it's an ion dipole bond + + + align:start position:0% +dipole it's an ion dipole bond +okay let's do this so that i + + align:start position:0% +okay let's do this so that i + + + align:start position:0% +okay let's do this so that i +stay within the lines + + align:start position:0% +stay within the lines + + + align:start position:0% +stay within the lines +all right now okay so what does that + + align:start position:0% +all right now okay so what does that + + + align:start position:0% +all right now okay so what does that +look like well we just said + + align:start position:0% +look like well we just said + + + align:start position:0% +look like well we just said +it's a charge i'm taking a single charge + + align:start position:0% +it's a charge i'm taking a single charge + + + align:start position:0% +it's a charge i'm taking a single charge +and i'm bringing it to this thing that + + align:start position:0% +and i'm bringing it to this thing that + + + align:start position:0% +and i'm bringing it to this thing that +has a shift of the charge within it + + align:start position:0% +has a shift of the charge within it + + + align:start position:0% +has a shift of the charge within it +that led to these two partial charges so + + align:start position:0% +that led to these two partial charges so + + + align:start position:0% +that led to these two partial charges so +as you as you can imagine it's going to + + align:start position:0% +as you as you can imagine it's going to + + + align:start position:0% +as you as you can imagine it's going to +want to orient + + align:start position:0% +want to orient + + + align:start position:0% +want to orient +to form a bond right so let's draw it + + align:start position:0% +to form a bond right so let's draw it + + + align:start position:0% +to form a bond right so let's draw it +that way right so maybe + + align:start position:0% +that way right so maybe + + + align:start position:0% +that way right so maybe +if i were to take hcl maybe i would have + + align:start position:0% +if i were to take hcl maybe i would have + + + align:start position:0% +if i were to take hcl maybe i would have +sort of like a + + align:start position:0% +sort of like a + + + align:start position:0% +sort of like a +you know a cloud like that right + + align:start position:0% +you know a cloud like that right + + + align:start position:0% +you know a cloud like that right +where it had its minus and it's plus + + align:start position:0% +where it had its minus and it's plus + + + align:start position:0% +where it had its minus and it's plus +there + + align:start position:0% +there + + + align:start position:0% +there +okay why did i i don't know why i used + + align:start position:0% +okay why did i i don't know why i used + + + align:start position:0% +okay why did i i don't know why i used +dashed lines but there you go + + align:start position:0% +dashed lines but there you go + + + align:start position:0% +dashed lines but there you go +and so and so you can see that that is + + align:start position:0% +and so and so you can see that that is + + + align:start position:0% +and so and so you can see that that is +what i wanted to put is the dashed line + + align:start position:0% +what i wanted to put is the dashed line + + + align:start position:0% +what i wanted to put is the dashed line +for the bond itself + + align:start position:0% +for the bond itself + + + align:start position:0% +for the bond itself +give myself a little space right + + align:start position:0% +give myself a little space right + + + align:start position:0% +give myself a little space right +that's the bond we're talking about + + align:start position:0% +that's the bond we're talking about + + + align:start position:0% +that's the bond we're talking about +that's the bomb we're talking now it + + align:start position:0% +that's the bomb we're talking now it + + + align:start position:0% +that's the bomb we're talking now it +turns out that this + + align:start position:0% +turns out that this + + + align:start position:0% +turns out that this +is an important type of interaction + + align:start position:0% +is an important type of interaction + + + align:start position:0% +is an important type of interaction +between molecules and ions + + align:start position:0% +between molecules and ions + + + align:start position:0% +between molecules and ions +it's an ion dipole interaction and it + + align:start position:0% +it's an ion dipole interaction and it + + + align:start position:0% +it's an ion dipole interaction and it +has a range + + align:start position:0% +has a range + + + align:start position:0% +has a range +i wrote it down it has a range + + align:start position:0% +i wrote it down it has a range + + + align:start position:0% +i wrote it down it has a range +of uh 40 to + + align:start position:0% +of uh 40 to + + + align:start position:0% +of uh 40 to +600 huge range + + align:start position:0% +600 huge range + + + align:start position:0% +600 huge range +40 to 600 and the the kind of attraction + + align:start position:0% +40 to 600 and the the kind of attraction + + + align:start position:0% +40 to 600 and the the kind of attraction +is really + + align:start position:0% +is really + + + align:start position:0% +is really +not describable in any other way than + + align:start position:0% +not describable in any other way than + + + align:start position:0% +not describable in any other way than +what we just described it's an ion and a + + align:start position:0% +what we just described it's an ion and a + + + align:start position:0% +what we just described it's an ion and a +dipole + + align:start position:0% +dipole + + + align:start position:0% +dipole +and it goes as one over r squared + + align:start position:0% +and it goes as one over r squared + + + align:start position:0% +and it goes as one over r squared +if you look at the separation the + + align:start position:0% +if you look at the separation the + + + align:start position:0% +if you look at the separation the +distance between these + + align:start position:0% +distance between these + + + align:start position:0% +distance between these +right that distance the dependence + + align:start position:0% +right that distance the dependence + + + align:start position:0% +right that distance the dependence +on the energy on the bond energy will go + + align:start position:0% +on the energy on the bond energy will go + + + align:start position:0% +on the energy on the bond energy will go +like that distance + + align:start position:0% +like that distance + + + align:start position:0% +like that distance +like one over that distance squared now + + align:start position:0% +like one over that distance squared now + + + align:start position:0% +like one over that distance squared now +these dependencies you can get from + + align:start position:0% +these dependencies you can get from + + + align:start position:0% +these dependencies you can get from +from fairly simple electrostatics okay i + + align:start position:0% +from fairly simple electrostatics okay i + + + align:start position:0% +from fairly simple electrostatics okay i +won't derive any of it i'm telling you + + align:start position:0% +won't derive any of it i'm telling you + + + align:start position:0% +won't derive any of it i'm telling you +what it is + + align:start position:0% +what it is + + + align:start position:0% +what it is +okay good okay so an ion tuple now an + + align:start position:0% +okay good okay so an ion tuple now an + + + align:start position:0% +okay good okay so an ion tuple now an +example of that would be + + align:start position:0% +example of that would be + + + align:start position:0% +example of that would be +the system that i just drew right so + + align:start position:0% +the system that i just drew right so + + + align:start position:0% +the system that i just drew right so +n a plus + + align:start position:0% +n a plus + + + align:start position:0% +n a plus +and h cl + + align:start position:0% +and h cl + + + align:start position:0% +and h cl +okay good that's a different kind of + + align:start position:0% +okay good that's a different kind of + + + align:start position:0% +okay good that's a different kind of +bond but see + + align:start position:0% +bond but see + + + align:start position:0% +bond but see +now i could also have two dipoles and i + + align:start position:0% +now i could also have two dipoles and i + + + align:start position:0% +now i could also have two dipoles and i +got a picture for that + + align:start position:0% +got a picture for that + + + align:start position:0% +got a picture for that +well what happened so here's a dipole + + align:start position:0% +well what happened so here's a dipole + + + align:start position:0% +well what happened so here's a dipole +there's my hcl dipole there it is with + + align:start position:0% +there's my hcl dipole there it is with + + + align:start position:0% +there's my hcl dipole there it is with +the negative + + align:start position:0% +the negative + + + align:start position:0% +the negative +partial charge and a positive partial + + align:start position:0% +partial charge and a positive partial + + + align:start position:0% +partial charge and a positive partial +charge and it's also color coded + + align:start position:0% +charge and it's also color coded + + + align:start position:0% +charge and it's also color coded +right okay so that's cool and there they + + align:start position:0% +right okay so that's cool and there they + + + align:start position:0% +right okay so that's cool and there they +are just floating along + + align:start position:0% +are just floating along + + + align:start position:0% +are just floating along +and i put an electric field on and i put + + align:start position:0% +and i put an electric field on and i put + + + align:start position:0% +and i put an electric field on and i put +an electric field on + + align:start position:0% +an electric field on + + + align:start position:0% +an electric field on +and and you can see that with the + + align:start position:0% +and and you can see that with the + + + align:start position:0% +and and you can see that with the +electric field so there's my positive + + align:start position:0% +electric field so there's my positive + + + align:start position:0% +electric field so there's my positive +plate my negative plate they're going to + + align:start position:0% +plate my negative plate they're going to + + + align:start position:0% +plate my negative plate they're going to +try to align + + align:start position:0% +try to align + + + align:start position:0% +try to align +right these dipoles mean that they're + + align:start position:0% +right these dipoles mean that they're + + + align:start position:0% +right these dipoles mean that they're +going to align with the field + + align:start position:0% +going to align with the field + + + align:start position:0% +going to align with the field +they're going to align with the field so + + align:start position:0% +they're going to align with the field so + + + align:start position:0% +they're going to align with the field so +all of those positive + + align:start position:0% +all of those positive + + + align:start position:0% +all of those positive +edges are going to try to turn and face + + align:start position:0% +edges are going to try to turn and face + + + align:start position:0% +edges are going to try to turn and face +the negative one and all those + + align:start position:0% +the negative one and all those + + + align:start position:0% +the negative one and all those +negative ones are going to turn and face + + align:start position:0% +negative ones are going to turn and face + + + align:start position:0% +negative ones are going to turn and face +the positive one + + align:start position:0% +the positive one + + + align:start position:0% +the positive one +um and that's exactly what we just did + + align:start position:0% +um and that's exactly what we just did + + + align:start position:0% +um and that's exactly what we just did +with this ion + + align:start position:0% +with this ion + + + align:start position:0% +with this ion +we basically did the same thing here + + align:start position:0% +we basically did the same thing here + + + align:start position:0% +we basically did the same thing here +that's what the ion did + + align:start position:0% +that's what the ion did + + + align:start position:0% +that's what the ion did +okay that's what the ion did it said hey + + align:start position:0% +okay that's what the ion did it said hey + + + align:start position:0% +okay that's what the ion did it said hey +come and face me and let's form a bond + + align:start position:0% +come and face me and let's form a bond + + + align:start position:0% +come and face me and let's form a bond +but but these these can also be + + align:start position:0% +but but these these can also be + + + align:start position:0% +but but these these can also be +attracted to each other + + align:start position:0% +attracted to each other + + + align:start position:0% +attracted to each other +right and so i've got a picture there so + + align:start position:0% +right and so i've got a picture there so + + + align:start position:0% +right and so i've got a picture there so +you can see like if i have a dipole and + + align:start position:0% +you can see like if i have a dipole and + + + align:start position:0% +you can see like if i have a dipole and +another dipole so this is not an + + align:start position:0% +another dipole so this is not an + + + align:start position:0% +another dipole so this is not an +external field and it's not an ion it's + + align:start position:0% +external field and it's not an ion it's + + + align:start position:0% +external field and it's not an ion it's +two dipoles + + align:start position:0% +two dipoles + + + align:start position:0% +two dipoles +two hcl molecules right well they each + + align:start position:0% +two hcl molecules right well they each + + + align:start position:0% +two hcl molecules right well they each +have a plus charge and a minus charge + + align:start position:0% +have a plus charge and a minus charge + + + align:start position:0% +have a plus charge and a minus charge +they each have a plus charge in the + + align:start position:0% +they each have a plus charge in the + + + align:start position:0% +they each have a plus charge in the +minus charge and a partial charge + + align:start position:0% +minus charge and a partial charge + + + align:start position:0% +minus charge and a partial charge +right polar covalent and you can see + + align:start position:0% +right polar covalent and you can see + + + align:start position:0% +right polar covalent and you can see +that those could line up actually in + + align:start position:0% +that those could line up actually in + + + align:start position:0% +that those could line up actually in +different ways to form + + align:start position:0% +different ways to form + + + align:start position:0% +different ways to form +attraction and they could also repel + + align:start position:0% +attraction and they could also repel + + + align:start position:0% +attraction and they could also repel +right but overall when they get together + + align:start position:0% +right but overall when they get together + + + align:start position:0% +right but overall when they get together +or when two of them get together they're + + align:start position:0% +or when two of them get together they're + + + align:start position:0% +or when two of them get together they're +going to find a way to attract because + + align:start position:0% +going to find a way to attract because + + + align:start position:0% +going to find a way to attract because +they can + + align:start position:0% +they can + + + align:start position:0% +they can +because they can't and so that is + + align:start position:0% +because they can't and so that is + + + align:start position:0% +because they can't and so that is +another kind of + + align:start position:0% +another kind of + + + align:start position:0% +another kind of +intermolecular attraction and it's + + align:start position:0% +intermolecular attraction and it's + + + align:start position:0% +intermolecular attraction and it's +called a dipole-dipole + + align:start position:0% +called a dipole-dipole + + + align:start position:0% +called a dipole-dipole +dipole dipole + + align:start position:0% +dipole dipole + + + align:start position:0% +dipole dipole +but let's draw this oh it's + + align:start position:0% + + + + align:start position:0% + +and if we do that we have + + align:start position:0% +and if we do that we have + + + align:start position:0% +and if we do that we have +uh let's see i'm going to try to draw + + align:start position:0% +uh let's see i'm going to try to draw + + + align:start position:0% +uh let's see i'm going to try to draw +this + + align:start position:0% +this + + + align:start position:0% +this +so i've got one dipole i'm going to + + align:start position:0% +so i've got one dipole i'm going to + + + align:start position:0% +so i've got one dipole i'm going to +stick to that picture + + align:start position:0% +stick to that picture + + + align:start position:0% +stick to that picture +i'm going to stick to this picture but + + align:start position:0% +i'm going to stick to this picture but + + + align:start position:0% +i'm going to stick to this picture but +it's the same as this picture + + align:start position:0% +it's the same as this picture + + + align:start position:0% +it's the same as this picture +right where i'm actually using the kind + + align:start position:0% +right where i'm actually using the kind + + + align:start position:0% +right where i'm actually using the kind +of shape here + + align:start position:0% +of shape here + + + align:start position:0% +of shape here +to show you that more charge has gone + + align:start position:0% +to show you that more charge has gone + + + align:start position:0% +to show you that more charge has gone +over to one side + + align:start position:0% +over to one side + + + align:start position:0% +over to one side +okay so let's go back to here right and + + align:start position:0% +okay so let's go back to here right and + + + align:start position:0% +okay so let's go back to here right and +so but if that happens + + align:start position:0% +so but if that happens + + + align:start position:0% +so but if that happens +then i've got minus and plus thank you + + align:start position:0% +then i've got minus and plus thank you + + + align:start position:0% +then i've got minus and plus thank you +okay and then i'm going to have another + + align:start position:0% +okay and then i'm going to have another + + + align:start position:0% +okay and then i'm going to have another +another one's going to want to line up + + align:start position:0% +another one's going to want to line up + + + align:start position:0% +another one's going to want to line up +like this + + align:start position:0% +like this + + + align:start position:0% +like this +oh did i do that right yeah and this is + + align:start position:0% +oh did i do that right yeah and this is + + + align:start position:0% +oh did i do that right yeah and this is +my + + align:start position:0% +my + + + align:start position:0% +my +this is the bond this dashed line here + + align:start position:0% +this is the bond this dashed line here + + + align:start position:0% +this is the bond this dashed line here +is the kind of bond that we're talking + + align:start position:0% +is the kind of bond that we're talking + + + align:start position:0% +is the kind of bond that we're talking +about + + align:start position:0% +about + + + align:start position:0% +about +yeah those are almost sort of asymmetric + + align:start position:0% +yeah those are almost sort of asymmetric + + + align:start position:0% +yeah those are almost sort of asymmetric +okay now goes in tight now that's a + + align:start position:0% +okay now goes in tight now that's a + + + align:start position:0% +okay now goes in tight now that's a +dipole dipole we don't really have a + + align:start position:0% +dipole dipole we don't really have a + + + align:start position:0% +dipole dipole we don't really have a +better way of calling that either + + align:start position:0% +better way of calling that either + + + align:start position:0% +better way of calling that either +they're dipole + + align:start position:0% +they're dipole + + + align:start position:0% +they're dipole +uh charges interacting with dipole + + align:start position:0% +uh charges interacting with dipole + + + align:start position:0% +uh charges interacting with dipole +charges and that's going to give you a + + align:start position:0% +charges and that's going to give you a + + + align:start position:0% +charges and that's going to give you a +one over + + align:start position:0% +one over + + + align:start position:0% +one over +r cubed dependence and then you know if + + align:start position:0% +r cubed dependence and then you know if + + + align:start position:0% +r cubed dependence and then you know if +you've taken some basic e + + align:start position:0% +you've taken some basic e + + + align:start position:0% +you've taken some basic e +m or if you do you'll learn this right + + align:start position:0% +m or if you do you'll learn this right + + + align:start position:0% +m or if you do you'll learn this right +you'll learn how to derive these + + align:start position:0% +you'll learn how to derive these + + + align:start position:0% +you'll learn how to derive these +these distance dependencies so i've got + + align:start position:0% +these distance dependencies so i've got + + + align:start position:0% +these distance dependencies so i've got +two dipoles + + align:start position:0% +two dipoles + + + align:start position:0% +two dipoles +right because there are two molecules + + align:start position:0% +right because there are two molecules + + + align:start position:0% +right because there are two molecules +that have + + align:start position:0% +that have + + + align:start position:0% +that have +not it's not a non-polar it's a polar + + align:start position:0% +not it's not a non-polar it's a polar + + + align:start position:0% +not it's not a non-polar it's a polar +covalent bond + + align:start position:0% +covalent bond + + + align:start position:0% +covalent bond +and those are attracted to each other in + + align:start position:0% +and those are attracted to each other in + + + align:start position:0% +and those are attracted to each other in +this way and the range of that bonding + + align:start position:0% +this way and the range of that bonding + + + align:start position:0% +this way and the range of that bonding +strength for two dipoles + + align:start position:0% +strength for two dipoles + + + align:start position:0% +strength for two dipoles +is 5 to 25 so it's a lot less + + align:start position:0% +is 5 to 25 so it's a lot less + + + align:start position:0% +is 5 to 25 so it's a lot less +right and let's well if you had + + align:start position:0% +right and let's well if you had + + + align:start position:0% +right and let's well if you had +hcl and hcl that would be an example + + align:start position:0% +hcl and hcl that would be an example + + + align:start position:0% +hcl and hcl that would be an example +no now instead of an ion i'm putting two + + align:start position:0% +no now instead of an ion i'm putting two + + + align:start position:0% +no now instead of an ion i'm putting two +polar molecules in + + align:start position:0% +polar molecules in + + + align:start position:0% +polar molecules in +right so but this could happen + + align:start position:0% +right so but this could happen + + + align:start position:0% +right so but this could happen +this could happen um from + + align:start position:0% +this could happen um from + + + align:start position:0% +this could happen um from +an atom from a molecule to a molecule it + + align:start position:0% +an atom from a molecule to a molecule it + + + align:start position:0% +an atom from a molecule to a molecule it +could happen from + + align:start position:0% +could happen from + + + align:start position:0% +could happen from +an atom to a molecule you it could + + align:start position:0% +an atom to a molecule you it could + + + align:start position:0% +an atom to a molecule you it could +happen from a molecule + + align:start position:0% +happen from a molecule + + + align:start position:0% +happen from a molecule +to an atom so so + + align:start position:0% +to an atom so so + + + align:start position:0% +to an atom so so +for for example you know i could have um + + align:start position:0% +for for example you know i could have um + + + align:start position:0% +for for example you know i could have um +if i have hcl and + + align:start position:0% +if i have hcl and + + + align:start position:0% +if i have hcl and +this has more charge has gone + + align:start position:0% +this has more charge has gone + + + align:start position:0% +this has more charge has gone +to the you know to the chlorine side + + align:start position:0% +to the you know to the chlorine side + + + align:start position:0% +to the you know to the chlorine side +right so this has my delta plus this is + + align:start position:0% +right so this has my delta plus this is + + + align:start position:0% +right so this has my delta plus this is +what i wrote over on the other side + + align:start position:0% +what i wrote over on the other side + + + align:start position:0% +what i wrote over on the other side +that's my delta minus + + align:start position:0% +that's my delta minus + + + align:start position:0% +that's my delta minus +and if i have just a single atom i'm + + align:start position:0% +and if i have just a single atom i'm + + + align:start position:0% +and if i have just a single atom i'm +going to put a xenon atom here + + align:start position:0% +going to put a xenon atom here + + + align:start position:0% +going to put a xenon atom here +well it's just sitting around happily + + align:start position:0% +well it's just sitting around happily + + + align:start position:0% +well it's just sitting around happily +you know + + align:start position:0% +you know + + + align:start position:0% +you know +minding its own business and what's + + align:start position:0% +minding its own business and what's + + + align:start position:0% +minding its own business and what's +gonna happen to that + + align:start position:0% +gonna happen to that + + + align:start position:0% +gonna happen to that +right what's gonna happen to that well + + align:start position:0% +right what's gonna happen to that well + + + align:start position:0% +right what's gonna happen to that well +see if if this comes up to + + align:start position:0% +see if if this comes up to + + + align:start position:0% +see if if this comes up to +an atom that wasn't that didn't have a + + align:start position:0% +an atom that wasn't that didn't have a + + + align:start position:0% +an atom that wasn't that didn't have a +dipole + + align:start position:0% +dipole + + + align:start position:0% +dipole +it still has feelings it still has + + align:start position:0% +it still has feelings it still has + + + align:start position:0% +it still has feelings it still has +feelings + + align:start position:0% +feelings + + + align:start position:0% +feelings +why because electrons have feelings + + align:start position:0% +why because electrons have feelings + + + align:start position:0% +why because electrons have feelings +that's why because it has electrons + + align:start position:0% +that's why because it has electrons + + + align:start position:0% +that's why because it has electrons +so those electrons are in there and it + + align:start position:0% +so those electrons are in there and it + + + align:start position:0% +so those electrons are in there and it +doesn't have a dipole + + align:start position:0% +doesn't have a dipole + + + align:start position:0% +doesn't have a dipole +but that's okay because those electrons + + align:start position:0% +but that's okay because those electrons + + + align:start position:0% +but that's okay because those electrons +still can feel + + align:start position:0% +still can feel + + + align:start position:0% +still can feel +they can feel the dipole of this + + align:start position:0% +they can feel the dipole of this + + + align:start position:0% +they can feel the dipole of this +they can feel the dipole of this + + align:start position:0% +they can feel the dipole of this + + + align:start position:0% +they can feel the dipole of this +molecule + + align:start position:0% + + + + align:start position:0% + +and when they feel that dipole they + + align:start position:0% +and when they feel that dipole they + + + align:start position:0% +and when they feel that dipole they +react to it + + align:start position:0% +react to it + + + align:start position:0% +react to it +they react to it right so there's a + + align:start position:0% +they react to it right so there's a + + + align:start position:0% +they react to it right so there's a +whole nother thing that can happen by + + align:start position:0% +whole nother thing that can happen by + + + align:start position:0% +whole nother thing that can happen by +the way it could happen + + align:start position:0% +the way it could happen + + + align:start position:0% +the way it could happen +oh that could it could happen with a + + align:start position:0% +oh that could it could happen with a + + + align:start position:0% +oh that could it could happen with a +sodium atom + + align:start position:0% +sodium atom + + + align:start position:0% +sodium atom +and a plus also is a charge + + align:start position:0% +and a plus also is a charge + + + align:start position:0% +and a plus also is a charge +that that this happy go lucky xena it + + align:start position:0% +that that this happy go lucky xena it + + + align:start position:0% +that that this happy go lucky xena it +doesn't it doesn't know what's coming + + align:start position:0% +doesn't it doesn't know what's coming + + + align:start position:0% +doesn't it doesn't know what's coming +but it's got electrons that feel charge + + align:start position:0% +but it's got electrons that feel charge + + + align:start position:0% +but it's got electrons that feel charge +and so you bring a charge to it and + + align:start position:0% +and so you bring a charge to it and + + + align:start position:0% +and so you bring a charge to it and +they're going to react to it + + align:start position:0% +they're going to react to it + + + align:start position:0% +they're going to react to it +they're going to react to it whether + + align:start position:0% +they're going to react to it whether + + + align:start position:0% +they're going to react to it whether +it's a single charge + + align:start position:0% +it's a single charge + + + align:start position:0% +it's a single charge +or whether it's a dipole these are + + align:start position:0% +or whether it's a dipole these are + + + align:start position:0% +or whether it's a dipole these are +charges + + align:start position:0% +charges + + + align:start position:0% +charges +they're going to change the charge + + align:start position:0% +they're going to change the charge + + + align:start position:0% +they're going to change the charge +around that + + align:start position:0% +around that + + + align:start position:0% +around that +atom now there's another name for that + + align:start position:0% +atom now there's another name for that + + + align:start position:0% +atom now there's another name for that +and and that leads to another kind of + + align:start position:0% +and and that leads to another kind of + + + align:start position:0% +and and that leads to another kind of +bond + + align:start position:0% +bond + + + align:start position:0% +bond +actually leads to another kind of bond + + align:start position:0% +actually leads to another kind of bond + + + align:start position:0% +actually leads to another kind of bond +let's see so i'm going to just + + align:start position:0% +let's see so i'm going to just + + + align:start position:0% +let's see so i'm going to just +let me draw the cartoon i really want to + + align:start position:0% +let me draw the cartoon i really want to + + + align:start position:0% +let me draw the cartoon i really want to +make sure you understand this + + align:start position:0% +make sure you understand this + + + align:start position:0% +make sure you understand this +because this sent sets up the next kind + + align:start position:0% +because this sent sets up the next kind + + + align:start position:0% +because this sent sets up the next kind +of bonding + + align:start position:0% +of bonding + + + align:start position:0% +of bonding +and so let's suppose i take a sodium + + align:start position:0% +and so let's suppose i take a sodium + + + align:start position:0% +and so let's suppose i take a sodium +atom + + align:start position:0% +atom + + + align:start position:0% +atom +and i'll use h2 h gazentite + + align:start position:0% +and i'll use h2 h gazentite + + + align:start position:0% +and i'll use h2 h gazentite +h i could have been a single atom it + + align:start position:0% +h i could have been a single atom it + + + align:start position:0% +h i could have been a single atom it +could have been a it could be a nonpolar + + align:start position:0% +could have been a it could be a nonpolar + + + align:start position:0% +could have been a it could be a nonpolar +molecule + + align:start position:0% +molecule + + + align:start position:0% +molecule +right so this is what this looks like + + align:start position:0% +right so this is what this looks like + + + align:start position:0% +right so this is what this looks like +and now this this is going to + + align:start position:0% +and now this this is going to + + + align:start position:0% +and now this this is going to +these are kind of walking along happily + + align:start position:0% +these are kind of walking along happily + + + align:start position:0% +these are kind of walking along happily +and then they see each other + + align:start position:0% +and then they see each other + + + align:start position:0% +and then they see each other +and all of a sudden this is going to + + align:start position:0% +and all of a sudden this is going to + + + align:start position:0% +and all of a sudden this is going to +induce a shift of the charge around + + align:start position:0% +induce a shift of the charge around + + + align:start position:0% +induce a shift of the charge around +those + + align:start position:0% +those + + + align:start position:0% +those +around that h2 molecule so what you're + + align:start position:0% +around that h2 molecule so what you're + + + align:start position:0% +around that h2 molecule so what you're +going to see is now + + align:start position:0% +going to see is now + + + align:start position:0% +going to see is now +more which way is it going to go + + align:start position:0% +more which way is it going to go + + + align:start position:0% +more which way is it going to go +which should have the bigger side the + + align:start position:0% +which should have the bigger side the + + + align:start position:0% +which should have the bigger side the +more charge right yeah here because + + align:start position:0% +more charge right yeah here because + + + align:start position:0% +more charge right yeah here because +that's positive and electrons are + + align:start position:0% +that's positive and electrons are + + + align:start position:0% +that's positive and electrons are +negative so now + + align:start position:0% +negative so now + + + align:start position:0% +negative so now +it's going to look like this now + + align:start position:0% +it's going to look like this now + + + align:start position:0% +it's going to look like this now +that was not a dipole it is not a + + align:start position:0% +that was not a dipole it is not a + + + align:start position:0% +that was not a dipole it is not a +molecule with a dipole + + align:start position:0% +molecule with a dipole + + + align:start position:0% +molecule with a dipole +but it's an induced dipole induced + + align:start position:0% +but it's an induced dipole induced + + + align:start position:0% +but it's an induced dipole induced +dipole because of feelings + + align:start position:0% +dipole because of feelings + + + align:start position:0% +dipole because of feelings +it comes down to feelings well that has + + align:start position:0% +it comes down to feelings well that has + + + align:start position:0% +it comes down to feelings well that has +a name + + align:start position:0% +a name + + + align:start position:0% +a name +right that's ion that one right there is + + align:start position:0% +right that's ion that one right there is + + + align:start position:0% +right that's ion that one right there is +ion + + align:start position:0% +ion + + + align:start position:0% +ion +induced see if i can fit it all here + + align:start position:0% +induced see if i can fit it all here + + + align:start position:0% +induced see if i can fit it all here +induced + + align:start position:0% +induced + + + align:start position:0% +induced +dipole ion induced dipole and i'm going + + align:start position:0% +dipole ion induced dipole and i'm going + + + align:start position:0% +dipole ion induced dipole and i'm going +to try to draw this now let's see + + align:start position:0% +to try to draw this now let's see + + + align:start position:0% +to try to draw this now let's see +okay hang on uh + + align:start position:0% +okay hang on uh + + + align:start position:0% +okay hang on uh +okay so the ion induced dipole + + align:start position:0% +okay so the ion induced dipole + + + align:start position:0% +okay so the ion induced dipole +i'm going to have a plus charge here and + + align:start position:0% +i'm going to have a plus charge here and + + + align:start position:0% +i'm going to have a plus charge here and +here's what i'm going to do i'm going to + + align:start position:0% +here's what i'm going to do i'm going to + + + align:start position:0% +here's what i'm going to do i'm going to +draw the + + align:start position:0% +draw the + + + align:start position:0% +draw the +original shape as what it was + + align:start position:0% + + + + align:start position:0% + +oh boy here we go that's what it was + + align:start position:0% +oh boy here we go that's what it was + + + align:start position:0% +oh boy here we go that's what it was +but then it got induced + + align:start position:0% + + + + align:start position:0% + +okay it got induced and so then once + + align:start position:0% +okay it got induced and so then once + + + align:start position:0% +okay it got induced and so then once +it's induced you've got like a minus + + align:start position:0% +it's induced you've got like a minus + + + align:start position:0% +it's induced you've got like a minus +and a plus happens + + align:start position:0% +and a plus happens + + + align:start position:0% +and a plus happens +all the time it happens all the time + + align:start position:0% +all the time it happens all the time + + + align:start position:0% +all the time it happens all the time +now um the the way that we'll we'll talk + + align:start position:0% +now um the the way that we'll we'll talk + + + align:start position:0% +now um the the way that we'll we'll talk +about this in a little bit of a + + align:start position:0% +about this in a little bit of a + + + align:start position:0% +about this in a little bit of a +different way because + + align:start position:0% +different way because + + + align:start position:0% +different way because +this attraction is between an ion by the + + align:start position:0% +this attraction is between an ion by the + + + align:start position:0% +this attraction is between an ion by the +way an ion just means an atom + + align:start position:0% +way an ion just means an atom + + + align:start position:0% +way an ion just means an atom +or something lost to charge right or has + + align:start position:0% +or something lost to charge right or has + + + align:start position:0% +or something lost to charge right or has +a charge plus or binos + + align:start position:0% +a charge plus or binos + + + align:start position:0% +a charge plus or binos +remember cation anion + + align:start position:0% +remember cation anion + + + align:start position:0% +remember cation anion +but the ion in this case is interacting + + align:start position:0% +but the ion in this case is interacting + + + align:start position:0% +but the ion in this case is interacting +with + + align:start position:0% +with + + + align:start position:0% +with +what is called a polarizable + + align:start position:0% +what is called a polarizable + + + align:start position:0% +what is called a polarizable +polarizable + + align:start position:0% +polarizable + + + align:start position:0% +polarizable +electron cloud now the electron cloud is + + align:start position:0% +electron cloud now the electron cloud is + + + align:start position:0% +electron cloud now the electron cloud is +nothing new we got + + align:start position:0% +nothing new we got + + + align:start position:0% +nothing new we got +we we got electron cloud nailed we know + + align:start position:0% +we we got electron cloud nailed we know + + + align:start position:0% +we we got electron cloud nailed we know +about electron cloud + + align:start position:0% +about electron cloud + + + align:start position:0% +about electron cloud +right because those are orbitals + + align:start position:0% +right because those are orbitals + + + align:start position:0% +right because those are orbitals +but what is this thing called + + align:start position:0% +but what is this thing called + + + align:start position:0% +but what is this thing called +polarizable right polarizable and that's + + align:start position:0% +polarizable right polarizable and that's + + + align:start position:0% +polarizable right polarizable and that's +a very important term so i'm going to + + align:start position:0% +a very important term so i'm going to + + + align:start position:0% +a very important term so i'm going to +write down + + align:start position:0% +write down + + + align:start position:0% +write down +its definition + + align:start position:0% + + + + align:start position:0% + +because you can imagine that if + + align:start position:0% +because you can imagine that if + + + align:start position:0% +because you can imagine that if +if i have a way of being attracted to a + + align:start position:0% +if i have a way of being attracted to a + + + align:start position:0% +if i have a way of being attracted to a +nonpolar molecule + + align:start position:0% +nonpolar molecule + + + align:start position:0% +nonpolar molecule +by shifting its charge by shifting its + + align:start position:0% +by shifting its charge by shifting its + + + align:start position:0% +by shifting its charge by shifting its +cloud + + align:start position:0% +cloud + + + align:start position:0% +cloud +then how easy was that how much could i + + align:start position:0% +then how easy was that how much could i + + + align:start position:0% +then how easy was that how much could i +shift it + + align:start position:0% +shift it + + + align:start position:0% +shift it +you can tell that that's going to affect + + align:start position:0% +you can tell that that's going to affect + + + align:start position:0% +you can tell that that's going to affect +the bond strength by the way which + + align:start position:0% +the bond strength by the way which + + + align:start position:0% +the bond strength by the way which +is let's see 3 to 15 + + align:start position:0% +is let's see 3 to 15 + + + align:start position:0% +is let's see 3 to 15 +and has a 1 over r to the 4th + + align:start position:0% +and has a 1 over r to the 4th + + + align:start position:0% +and has a 1 over r to the 4th +dependence and let's give us + + align:start position:0% +dependence and let's give us + + + align:start position:0% +dependence and let's give us +let's give the example that i gave there + + align:start position:0% +let's give the example that i gave there + + + align:start position:0% +let's give the example that i gave there +n a plus + + align:start position:0% +n a plus + + + align:start position:0% +n a plus +and h h + + align:start position:0% +and h h + + + align:start position:0% +and h h +okay nonpolar molecule again it could + + align:start position:0% +okay nonpolar molecule again it could + + + align:start position:0% +okay nonpolar molecule again it could +have been an atom + + align:start position:0% +have been an atom + + + align:start position:0% +have been an atom +but it could have been a nonpolar + + align:start position:0% +but it could have been a nonpolar + + + align:start position:0% +but it could have been a nonpolar +molecule + + align:start position:0% +molecule + + + align:start position:0% +molecule +yeah no polarizable polarizability + + align:start position:0% +yeah no polarizable polarizability + + + align:start position:0% +yeah no polarizable polarizability +is a very important concept + + align:start position:0% +is a very important concept + + + align:start position:0% +is a very important concept +polarizability + + align:start position:0% + + + + align:start position:0% + +is the measure + + align:start position:0% +is the measure + + + align:start position:0% +is the measure +because then tight of how + + align:start position:0% +because then tight of how + + + align:start position:0% +because then tight of how +easy + + align:start position:0% + + + + align:start position:0% + +it is to temporarily + + align:start position:0% + + + + align:start position:0% + +temporarily distort + + align:start position:0% + + + + align:start position:0% + +the electron distribution + + align:start position:0% + + + + align:start position:0% + +that is a very important concept + + align:start position:0% +that is a very important concept + + + align:start position:0% +that is a very important concept +for these types of bonds and for a lot + + align:start position:0% +for these types of bonds and for a lot + + + align:start position:0% +for these types of bonds and for a lot +of other properties and of course for + + align:start position:0% +of other properties and of course for + + + align:start position:0% +of other properties and of course for +life in general + + align:start position:0% +life in general + + + align:start position:0% +life in general +how polarizable are my electrons i need + + align:start position:0% +how polarizable are my electrons i need + + + align:start position:0% +how polarizable are my electrons i need +to know + + align:start position:0% + + + + align:start position:0% + +are they just willing to deform from + + align:start position:0% +are they just willing to deform from + + + align:start position:0% +are they just willing to deform from +their their happy orbitals + + align:start position:0% +their their happy orbitals + + + align:start position:0% +their their happy orbitals +temporarily temporarily because + + align:start position:0% +temporarily temporarily because + + + align:start position:0% +temporarily temporarily because +if they were going to deform permanently + + align:start position:0% +if they were going to deform permanently + + + align:start position:0% +if they were going to deform permanently +then you'd have a dipole a permanent + + align:start position:0% +then you'd have a dipole a permanent + + + align:start position:0% +then you'd have a dipole a permanent +dipole + + align:start position:0% +dipole + + + align:start position:0% +dipole +these are induced dipoles okay + + align:start position:0% +these are induced dipoles okay + + + align:start position:0% +these are induced dipoles okay +that's important okay + + align:start position:0% +that's important okay + + + align:start position:0% +that's important okay +now now okay good so that's an + + align:start position:0% +now now okay good so that's an + + + align:start position:0% +now now okay good so that's an +ion-induced dipole now + + align:start position:0% +ion-induced dipole now + + + align:start position:0% +ion-induced dipole now +you could also imagine you know this + + align:start position:0% +you could also imagine you know this + + + align:start position:0% +you could also imagine you know this +could have easily been + + align:start position:0% +could have easily been + + + align:start position:0% +could have easily been +a dipole over here it didn't have to be + + align:start position:0% +a dipole over here it didn't have to be + + + align:start position:0% +a dipole over here it didn't have to be +an ion + + align:start position:0% +an ion + + + align:start position:0% +an ion +it could have been a dipole i could have + + align:start position:0% +it could have been a dipole i could have + + + align:start position:0% +it could have been a dipole i could have +had a dipole here that came up to a + + align:start position:0% +had a dipole here that came up to a + + + align:start position:0% +had a dipole here that came up to a +nonpolar molecule or an atom + + align:start position:0% +nonpolar molecule or an atom + + + align:start position:0% +nonpolar molecule or an atom +right and it could have uh it could have + + align:start position:0% +right and it could have uh it could have + + + align:start position:0% +right and it could have uh it could have +induced the same shift in the charge + + align:start position:0% +induced the same shift in the charge + + + align:start position:0% +induced the same shift in the charge +density which then allows me to be + + align:start position:0% +density which then allows me to be + + + align:start position:0% +density which then allows me to be +attracted + + align:start position:0% +attracted + + + align:start position:0% +attracted +because there's a little bit of a + + align:start position:0% +because there's a little bit of a + + + align:start position:0% +because there's a little bit of a +fluctuation of negative charge there + + align:start position:0% +fluctuation of negative charge there + + + align:start position:0% +fluctuation of negative charge there +right let's draw so if i were to + + align:start position:0% +right let's draw so if i were to + + + align:start position:0% +right let's draw so if i were to +oh so + + align:start position:0% +oh so + + + align:start position:0% +oh so +see the thing is we've been talking + + align:start position:0% +see the thing is we've been talking + + + align:start position:0% +see the thing is we've been talking +about dimers + + align:start position:0% +about dimers + + + align:start position:0% +about dimers +but you could talk about what is the + + align:start position:0% +but you could talk about what is the + + + align:start position:0% +but you could talk about what is the +dipole of something + + align:start position:0% +dipole of something + + + align:start position:0% +dipole of something +more than a dimer right so this is polar + + align:start position:0% +more than a dimer right so this is polar + + + align:start position:0% +more than a dimer right so this is polar +what about these other things + + align:start position:0% +what about these other things + + + align:start position:0% +what about these other things +right so if i look at molecules + + align:start position:0% +right so if i look at molecules + + + align:start position:0% +right so if i look at molecules +right that are polar it's not just about + + align:start position:0% +right that are polar it's not just about + + + align:start position:0% +right that are polar it's not just about +hcl + + align:start position:0% +hcl + + + align:start position:0% +hcl +right which is that first one up there + + align:start position:0% +right which is that first one up there + + + align:start position:0% +right which is that first one up there +but that's kind of + + align:start position:0% +but that's kind of + + + align:start position:0% +but that's kind of +the obvious case but what about ccl4 + + align:start position:0% +the obvious case but what about ccl4 + + + align:start position:0% +the obvious case but what about ccl4 +what if i take a carbon atom + + align:start position:0% +what if i take a carbon atom + + + align:start position:0% +what if i take a carbon atom +and i put four chlorines those are all + + align:start position:0% +and i put four chlorines those are all + + + align:start position:0% +and i put four chlorines those are all +polar bonds and you can see while it's + + align:start position:0% +polar bonds and you can see while it's + + + align:start position:0% +polar bonds and you can see while it's +hard to see but they've drawn in the + + align:start position:0% +hard to see but they've drawn in the + + + align:start position:0% +hard to see but they've drawn in the +dipole moment + + align:start position:0% +dipole moment + + + align:start position:0% +dipole moment +you've lost some charge from the carbon + + align:start position:0% +you've lost some charge from the carbon + + + align:start position:0% +you've lost some charge from the carbon +it's gone out to the chlorine atom + + align:start position:0% +it's gone out to the chlorine atom + + + align:start position:0% +it's gone out to the chlorine atom +there's a dipole moment within each bond + + align:start position:0% +there's a dipole moment within each bond + + + align:start position:0% +there's a dipole moment within each bond +but but now here's + + align:start position:0% +but but now here's + + + align:start position:0% +but but now here's +where vesper comes in because + + align:start position:0% +where vesper comes in because + + + align:start position:0% +where vesper comes in because +you know these are going to be + + align:start position:0% +you know these are going to be + + + align:start position:0% +you know these are going to be +tetrahedrally + + align:start position:0% +tetrahedrally + + + align:start position:0% +tetrahedrally +uh distributed and fully canceling out + + align:start position:0% +uh distributed and fully canceling out + + + align:start position:0% +uh distributed and fully canceling out +so it's like you've got all these kind + + align:start position:0% +so it's like you've got all these kind + + + align:start position:0% +so it's like you've got all these kind +of electrostatic things going on + + align:start position:0% +of electrostatic things going on + + + align:start position:0% +of electrostatic things going on +that all cancel out so this molecule is + + align:start position:0% +that all cancel out so this molecule is + + + align:start position:0% +that all cancel out so this molecule is +not a polar molecule + + align:start position:0% +not a polar molecule + + + align:start position:0% +not a polar molecule +right on the other hand molecules like + + align:start position:0% +right on the other hand molecules like + + + align:start position:0% +right on the other hand molecules like +nh3 + + align:start position:0% +nh3 + + + align:start position:0% +nh3 +or ch3cl right now this is going to be + + align:start position:0% +or ch3cl right now this is going to be + + + align:start position:0% +or ch3cl right now this is going to be +polar because + + align:start position:0% +polar because + + + align:start position:0% +polar because +these dipoles do not cancel out within + + align:start position:0% +these dipoles do not cancel out within + + + align:start position:0% +these dipoles do not cancel out within +the molecule so you can kind of use this + + align:start position:0% +the molecule so you can kind of use this + + + align:start position:0% +the molecule so you can kind of use this +thinking there's bf3 + + align:start position:0% +thinking there's bf3 + + + align:start position:0% +thinking there's bf3 +trigonal planar right all going to can + + align:start position:0% +trigonal planar right all going to can + + + align:start position:0% +trigonal planar right all going to can +all those dipoles cancel + + align:start position:0% +all those dipoles cancel + + + align:start position:0% +all those dipoles cancel +it's a non-polar molecule + + align:start position:0% +it's a non-polar molecule + + + align:start position:0% +it's a non-polar molecule +but if you take a classic example which + + align:start position:0% +but if you take a classic example which + + + align:start position:0% +but if you take a classic example which +we'll come back to + + align:start position:0% +we'll come back to + + + align:start position:0% +we'll come back to +of say water as a polar exam a polar + + align:start position:0% +of say water as a polar exam a polar + + + align:start position:0% +of say water as a polar exam a polar +molecule + + align:start position:0% +molecule + + + align:start position:0% +molecule +i could do the same thing right i can + + align:start position:0% +i could do the same thing right i can + + + align:start position:0% +i could do the same thing right i can +take water + + align:start position:0% +take water + + + align:start position:0% +take water +which is oxygen hydrogen hydrogen and + + align:start position:0% +which is oxygen hydrogen hydrogen and + + + align:start position:0% +which is oxygen hydrogen hydrogen and +you see you got delta plus there + + align:start position:0% +you see you got delta plus there + + + align:start position:0% +you see you got delta plus there +delta plus there and you got some minus + + align:start position:0% +delta plus there and you got some minus + + + align:start position:0% +delta plus there and you got some minus +there right + + align:start position:0% +there right + + + align:start position:0% +there right +now use it there's a dipole moment + + align:start position:0% +now use it there's a dipole moment + + + align:start position:0% +now use it there's a dipole moment +there's a dipole moment + + align:start position:0% +there's a dipole moment + + + align:start position:0% +there's a dipole moment +but they and so part of it cancels but + + align:start position:0% +but they and so part of it cancels but + + + align:start position:0% +but they and so part of it cancels but +not all of it so there is a dipole + + align:start position:0% +not all of it so there is a dipole + + + align:start position:0% +not all of it so there is a dipole +moment for the + + align:start position:0% +moment for the + + + align:start position:0% +moment for the +net water molecule the net dipole is + + align:start position:0% +net water molecule the net dipole is + + + align:start position:0% +net water molecule the net dipole is +what matters + + align:start position:0% +what matters + + + align:start position:0% +what matters +to determine if a molecule is polar or + + align:start position:0% +to determine if a molecule is polar or + + + align:start position:0% +to determine if a molecule is polar or +not right so there's a net dipole + + align:start position:0% +not right so there's a net dipole + + + align:start position:0% +not right so there's a net dipole +net dipole when you sum them all up and + + align:start position:0% +net dipole when you sum them all up and + + + align:start position:0% +net dipole when you sum them all up and +that's what's going to determine + + align:start position:0% +that's what's going to determine + + + align:start position:0% +that's what's going to determine +if this can come along to that xenon + + align:start position:0% +if this can come along to that xenon + + + align:start position:0% +if this can come along to that xenon +atom right + + align:start position:0% +atom right + + + align:start position:0% +atom right +and so here's my xenon atom just sitting + + align:start position:0% +and so here's my xenon atom just sitting + + + align:start position:0% +and so here's my xenon atom just sitting +there + + align:start position:0% +there + + + align:start position:0% +there +doing nothing and now when water comes + + align:start position:0% +doing nothing and now when water comes + + + align:start position:0% +doing nothing and now when water comes +up to xenon + + align:start position:0% +up to xenon + + + align:start position:0% +up to xenon +what's going to happen well what's going + + align:start position:0% +what's going to happen well what's going + + + align:start position:0% +what's going to happen well what's going +to happen is i've got my water molecule + + align:start position:0% +to happen is i've got my water molecule + + + align:start position:0% +to happen is i've got my water molecule +my water molecule my delta minus + + align:start position:0% +my water molecule my delta minus + + + align:start position:0% +my water molecule my delta minus +my delta plus my delta plus and because + + align:start position:0% +my delta plus my delta plus and because + + + align:start position:0% +my delta plus my delta plus and because +it's + + align:start position:0% +it's + + + align:start position:0% +it's +got a net dipole it's going to deform + + align:start position:0% +got a net dipole it's going to deform + + + align:start position:0% +got a net dipole it's going to deform +the atom right and so i'm going to have + + align:start position:0% +the atom right and so i'm going to have + + + align:start position:0% +the atom right and so i'm going to have +let's see make sure i draw this right so + + align:start position:0% +let's see make sure i draw this right so + + + align:start position:0% +let's see make sure i draw this right so +it's going to look kind of like this + + align:start position:0% + + + + align:start position:0% + +delta minus delta plus + + align:start position:0% +delta minus delta plus + + + align:start position:0% +delta minus delta plus +and that allows a water molecule to bond + + align:start position:0% +and that allows a water molecule to bond + + + align:start position:0% +and that allows a water molecule to bond +to a xenon + + align:start position:0% +to a xenon + + + align:start position:0% +to a xenon +atom it is bonding it is bonding + + align:start position:0% +atom it is bonding it is bonding + + + align:start position:0% +atom it is bonding it is bonding +with another bond which is very similar + + align:start position:0% +with another bond which is very similar + + + align:start position:0% +with another bond which is very similar +to the one i just wrote + + align:start position:0% +to the one i just wrote + + + align:start position:0% +to the one i just wrote +goes in tight but it is a dipole + + align:start position:0% +goes in tight but it is a dipole + + + align:start position:0% +goes in tight but it is a dipole +induced not ion it is a dipole + + align:start position:0% +induced not ion it is a dipole + + + align:start position:0% +induced not ion it is a dipole +induced dipole + + align:start position:0% +induced dipole + + + align:start position:0% +induced dipole +you see that because now i didn't have + + align:start position:0% +you see that because now i didn't have + + + align:start position:0% +you see that because now i didn't have +an ion i had a water molecule that had + + align:start position:0% +an ion i had a water molecule that had + + + align:start position:0% +an ion i had a water molecule that had +a dipole moment so now i've got my + + align:start position:0% +a dipole moment so now i've got my + + + align:start position:0% +a dipole moment so now i've got my +dipole induced dipole and that's going + + align:start position:0% +dipole induced dipole and that's going + + + align:start position:0% +dipole induced dipole and that's going +to look + + align:start position:0% +to look + + + align:start position:0% +to look +oh let's draw it let's see so i got my + + align:start position:0% +oh let's draw it let's see so i got my + + + align:start position:0% +oh let's draw it let's see so i got my +dipole-induced dipole so we're going to + + align:start position:0% +dipole-induced dipole so we're going to + + + align:start position:0% +dipole-induced dipole so we're going to +go + + align:start position:0% +go + + + align:start position:0% +go +kind of oh boy there we go + + align:start position:0% +kind of oh boy there we go + + + align:start position:0% +kind of oh boy there we go +okay minus plus + + align:start position:0% +okay minus plus + + + align:start position:0% +okay minus plus +and then we're gonna now that might be + + align:start position:0% +and then we're gonna now that might be + + + align:start position:0% +and then we're gonna now that might be +uh the dipole of say the water molecule + + align:start position:0% +uh the dipole of say the water molecule + + + align:start position:0% +uh the dipole of say the water molecule +or something like that and then i've got + + align:start position:0% +or something like that and then i've got + + + align:start position:0% +or something like that and then i've got +us another thing that was + + align:start position:0% +us another thing that was + + + align:start position:0% +us another thing that was +didn't have a dipole but it got induced + + align:start position:0% +didn't have a dipole but it got induced + + + align:start position:0% +didn't have a dipole but it got induced +to have one + + align:start position:0% +to have one + + + align:start position:0% +to have one +okay oh boy i went out of the lines + + align:start position:0% +okay oh boy i went out of the lines + + + align:start position:0% +okay oh boy i went out of the lines +ah i was so careful but you can't + + align:start position:0% +ah i was so careful but you can't + + + align:start position:0% +ah i was so careful but you can't +you can't hold chemistry back uh-uh + + align:start position:0% +you can't hold chemistry back uh-uh + + + align:start position:0% +you can't hold chemistry back uh-uh +no way no way + + align:start position:0% + + + + align:start position:0% + +okay delta plus delta minus + + align:start position:0% +okay delta plus delta minus + + + align:start position:0% +okay delta plus delta minus +it's induced that's what that means + + align:start position:0% +it's induced that's what that means + + + align:start position:0% +it's induced that's what that means +right + + align:start position:0% +right + + + align:start position:0% +right +now it turns out that this has an even + + align:start position:0% +now it turns out that this has an even + + + align:start position:0% +now it turns out that this has an even +weaker + + align:start position:0% +weaker + + + align:start position:0% +weaker +um so this would be a dipole let's just + + align:start position:0% +um so this would be a dipole let's just + + + align:start position:0% +um so this would be a dipole let's just +write let's finish this up + + align:start position:0% +write let's finish this up + + + align:start position:0% +write let's finish this up +dipole interacting with the polarizable + + align:start position:0% + + + + align:start position:0% + +electron cloud and the value of this + + align:start position:0% +electron cloud and the value of this + + + align:start position:0% +electron cloud and the value of this +is even lower range two to ten + + align:start position:0% +is even lower range two to ten + + + align:start position:0% +is even lower range two to ten +and the dependence is one over r to the + + align:start position:0% +and the dependence is one over r to the + + + align:start position:0% +and the dependence is one over r to the +sixth + + align:start position:0% +sixth + + + align:start position:0% +sixth +and the example let's do let's go back + + align:start position:0% +and the example let's do let's go back + + + align:start position:0% +and the example let's do let's go back +to hcl + + align:start position:0% +to hcl + + + align:start position:0% +to hcl +hcl there's my dipole coming in + + align:start position:0% +hcl there's my dipole coming in + + + align:start position:0% +hcl there's my dipole coming in +on clcl i like that because it's got + + align:start position:0% +on clcl i like that because it's got + + + align:start position:0% +on clcl i like that because it's got +three cls + + align:start position:0% +three cls + + + align:start position:0% +three cls +why not that's a non-polar molecule + + align:start position:0% +why not that's a non-polar molecule + + + align:start position:0% +why not that's a non-polar molecule +that's a that's a dipole that + + align:start position:0% +that's a that's a dipole that + + + align:start position:0% +that's a that's a dipole that +induces a dipole in this by shifting its + + align:start position:0% +induces a dipole in this by shifting its + + + align:start position:0% +induces a dipole in this by shifting its +polarizable electrons around + + align:start position:0% +polarizable electrons around + + + align:start position:0% +polarizable electrons around +right and and then it allows there to be + + align:start position:0% +right and and then it allows there to be + + + align:start position:0% +right and and then it allows there to be +a little bit of attraction + + align:start position:0% +a little bit of attraction + + + align:start position:0% +a little bit of attraction +maybe you might be saying but that's so + + align:start position:0% +maybe you might be saying but that's so + + + align:start position:0% +maybe you might be saying but that's so +little we'll get to that in a second + + align:start position:0% +little we'll get to that in a second + + + align:start position:0% +little we'll get to that in a second +that's not so little that's actually not + + align:start position:0% +that's not so little that's actually not + + + align:start position:0% +that's not so little that's actually not +so little when you got a lot of it + + align:start position:0% +so little when you got a lot of it + + + align:start position:0% +so little when you got a lot of it +okay okay dipole interaction now it + + align:start position:0% +okay okay dipole interaction now it + + + align:start position:0% +okay okay dipole interaction now it +turns out + + align:start position:0% +turns out + + + align:start position:0% +turns out +that even and this + + align:start position:0% +that even and this + + + align:start position:0% +that even and this +is what's mind-blowing you knew this was + + align:start position:0% +is what's mind-blowing you knew this was + + + align:start position:0% +is what's mind-blowing you knew this was +coming this moment today was going to + + align:start position:0% +coming this moment today was going to + + + align:start position:0% +coming this moment today was going to +come + + align:start position:0% +come + + + align:start position:0% +come +i can have an interaction + + align:start position:0% + + + + align:start position:0% + +without any dipole to start with + + align:start position:0% +without any dipole to start with + + + align:start position:0% +without any dipole to start with +it's true i can take two nonpolar + + align:start position:0% +it's true i can take two nonpolar + + + align:start position:0% +it's true i can take two nonpolar +covalent bonds + + align:start position:0% +covalent bonds + + + align:start position:0% +covalent bonds +two nonpolar covalent molecules h2 and + + align:start position:0% +two nonpolar covalent molecules h2 and + + + align:start position:0% +two nonpolar covalent molecules h2 and +h2 + + align:start position:0% +h2 + + + align:start position:0% +h2 +and they are attracted to each other + + align:start position:0% +and they are attracted to each other + + + align:start position:0% +and they are attracted to each other +how is that possible well it's what + + align:start position:0% +how is that possible well it's what + + + align:start position:0% +how is that possible well it's what +explains this + + align:start position:0% +explains this + + + align:start position:0% +explains this +i mean we know why does helium argon and + + align:start position:0% +i mean we know why does helium argon and + + + align:start position:0% +i mean we know why does helium argon and +xena why do these have different boiling + + align:start position:0% +xena why do these have different boiling + + + align:start position:0% +xena why do these have different boiling +points + + align:start position:0% +points + + + align:start position:0% +points +by the way the boiling point of these + + align:start position:0% +by the way the boiling point of these + + + align:start position:0% +by the way the boiling point of these +right so these can be made into liquids + + align:start position:0% +right so these can be made into liquids + + + align:start position:0% +right so these can be made into liquids +and you can boil them right + + align:start position:0% +and you can boil them right + + + align:start position:0% +and you can boil them right +uh is really different and it's a + + align:start position:0% +uh is really different and it's a + + + align:start position:0% +uh is really different and it's a +measure of how strongly + + align:start position:0% +measure of how strongly + + + align:start position:0% +measure of how strongly +they're bonded together right so this is + + align:start position:0% +they're bonded together right so this is + + + align:start position:0% +they're bonded together right so this is +a direct + + align:start position:0% +a direct + + + align:start position:0% +a direct +kind of way of thinking about of + + align:start position:0% +kind of way of thinking about of + + + align:start position:0% +kind of way of thinking about of +measuring something that's related to + + align:start position:0% +measuring something that's related to + + + align:start position:0% +measuring something that's related to +the bond strength so why do these + + align:start position:0% +the bond strength so why do these + + + align:start position:0% +the bond strength so why do these +atoms they're all just atoms + + align:start position:0% +atoms they're all just atoms + + + align:start position:0% +atoms they're all just atoms +you know they're all just like this + + align:start position:0% +you know they're all just like this + + + align:start position:0% +you know they're all just like this +they're not + + align:start position:0% +they're not + + + align:start position:0% +they're not +they don't have this this dipole right + + align:start position:0% +they don't have this this dipole right + + + align:start position:0% +they don't have this this dipole right +they're non-polar they're just atoms + + align:start position:0% +they're non-polar they're just atoms + + + align:start position:0% +they're non-polar they're just atoms +sitting there with their nice symmetric + + align:start position:0% +sitting there with their nice symmetric + + + align:start position:0% +sitting there with their nice symmetric +charge clouds + + align:start position:0% +charge clouds + + + align:start position:0% +charge clouds +how is it that they can be attracted to + + align:start position:0% +how is it that they can be attracted to + + + align:start position:0% +how is it that they can be attracted to +each other in the first place and how is + + align:start position:0% +each other in the first place and how is + + + align:start position:0% +each other in the first place and how is +it that they can have such a strong + + align:start position:0% +it that they can have such a strong + + + align:start position:0% +it that they can have such a strong +trend and that has to do with another + + align:start position:0% +trend and that has to do with another + + + align:start position:0% +trend and that has to do with another +kind of force + + align:start position:0% +kind of force + + + align:start position:0% +kind of force +and um and there's a picture so here's + + align:start position:0% +and um and there's a picture so here's + + + align:start position:0% +and um and there's a picture so here's +two examples + + align:start position:0% +two examples + + + align:start position:0% +two examples +there's two helium atoms so that's the + + align:start position:0% +there's two helium atoms so that's the + + + align:start position:0% +there's two helium atoms so that's the +first one in this list boiling point + + align:start position:0% +first one in this list boiling point + + + align:start position:0% +first one in this list boiling point +minus 269 degrees celsius is pretty cold + + align:start position:0% +minus 269 degrees celsius is pretty cold + + + align:start position:0% +minus 269 degrees celsius is pretty cold +and there's two non-polar molecules h2 + + align:start position:0% +and there's two non-polar molecules h2 + + + align:start position:0% +and there's two non-polar molecules h2 +what happens + + align:start position:0% +what happens + + + align:start position:0% +what happens +is that you get fluctuations you get + + align:start position:0% +is that you get fluctuations you get + + + align:start position:0% +is that you get fluctuations you get +fluctuations + + align:start position:0% +fluctuations + + + align:start position:0% +fluctuations +and and what i mean by that is that just + + align:start position:0% +and and what i mean by that is that just + + + align:start position:0% +and and what i mean by that is that just +randomly literally randomly right + + align:start position:0% +randomly literally randomly right + + + align:start position:0% +randomly literally randomly right +because of collisions or thermal uh + + align:start position:0% +because of collisions or thermal uh + + + align:start position:0% +because of collisions or thermal uh +energy randomly + + align:start position:0% +energy randomly + + + align:start position:0% +energy randomly +one of those could form a dipole + + align:start position:0% +one of those could form a dipole + + + align:start position:0% +one of those could form a dipole +was that i didn't mean it it wasn't my + + align:start position:0% +was that i didn't mean it it wasn't my + + + align:start position:0% +was that i didn't mean it it wasn't my +happy place but it happened + + align:start position:0% +happy place but it happened + + + align:start position:0% +happy place but it happened +now if it happens and and your charge + + align:start position:0% +now if it happens and and your charge + + + align:start position:0% +now if it happens and and your charge +kind of goes to one side + + align:start position:0% +kind of goes to one side + + + align:start position:0% +kind of goes to one side +even if it's just for a split second + + align:start position:0% +even if it's just for a split second + + + align:start position:0% +even if it's just for a split second +that's a dipole that then if you're near + + align:start position:0% +that's a dipole that then if you're near + + + align:start position:0% +that's a dipole that then if you're near +another atom + + align:start position:0% +another atom + + + align:start position:0% +another atom +can induce a dipole and we know that if + + align:start position:0% +can induce a dipole and we know that if + + + align:start position:0% +can induce a dipole and we know that if +we can induce a dipole if we're here + + align:start position:0% +we can induce a dipole if we're here + + + align:start position:0% +we can induce a dipole if we're here +if we're at this stage we've already got + + align:start position:0% +if we're at this stage we've already got + + + align:start position:0% +if we're at this stage we've already got +that covered we already know that i can + + align:start position:0% +that covered we already know that i can + + + align:start position:0% +that covered we already know that i can +induce another dipole if i'm charged + + align:start position:0% +induce another dipole if i'm charged + + + align:start position:0% +induce another dipole if i'm charged +right and so what happens is you get + + align:start position:0% +right and so what happens is you get + + + align:start position:0% +right and so what happens is you get +this kind of fluctuation + + align:start position:0% +this kind of fluctuation + + + align:start position:0% +this kind of fluctuation +that leads literally to a bond + + align:start position:0% +that leads literally to a bond + + + align:start position:0% +that leads literally to a bond +it leads to a bond right + + align:start position:0% +it leads to a bond right + + + align:start position:0% +it leads to a bond right +and that is called london dispersion + + align:start position:0% +and that is called london dispersion + + + align:start position:0% +and that is called london dispersion +that's called the london + + align:start position:0% +that's called the london + + + align:start position:0% +that's called the london +force and the london dispersion is the + + align:start position:0% +force and the london dispersion is the + + + align:start position:0% +force and the london dispersion is the +name of + + align:start position:0% +name of + + + align:start position:0% +name of +the kind of bonding you have let me just + + align:start position:0% +the kind of bonding you have let me just + + + align:start position:0% +the kind of bonding you have let me just +make sure + + align:start position:0% +make sure + + + align:start position:0% +make sure +okay london + + align:start position:0% + + + + align:start position:0% + +dispersion + + align:start position:0% + + + + align:start position:0% + +notice + + align:start position:0% +notice + + + align:start position:0% +notice +notice there's room for one more it's + + align:start position:0% +notice there's room for one more it's + + + align:start position:0% +notice there's room for one more it's +coming there's more + + align:start position:0% +coming there's more + + + align:start position:0% +coming there's more +we're not done we are not done + + align:start position:0% +we're not done we are not done + + + align:start position:0% +we're not done we are not done +i can literally take two nonpolar two + + align:start position:0% +i can literally take two nonpolar two + + + align:start position:0% +i can literally take two nonpolar two +nonpolar atoms or molecules + + align:start position:0% +nonpolar atoms or molecules + + + align:start position:0% +nonpolar atoms or molecules +and i can find a way for them to be + + align:start position:0% +and i can find a way for them to be + + + align:start position:0% +and i can find a way for them to be +attracted + + align:start position:0% +attracted + + + align:start position:0% +attracted +and the way it happens is thermal + + align:start position:0% +and the way it happens is thermal + + + align:start position:0% +and the way it happens is thermal +fluctuations + + align:start position:0% +fluctuations + + + align:start position:0% +fluctuations +this is such an important force and it's + + align:start position:0% +this is such an important force and it's + + + align:start position:0% +this is such an important force and it's +such a strange one + + align:start position:0% + + + + align:start position:0% + +that i want to write down what it is + + align:start position:0% +that i want to write down what it is + + + align:start position:0% +that i want to write down what it is +it's that + + align:start position:0% +it's that + + + align:start position:0% +it's that +non-polar we've been talking about polar + + align:start position:0% +non-polar we've been talking about polar + + + align:start position:0% +non-polar we've been talking about polar +and charges but + + align:start position:0% +and charges but + + + align:start position:0% +and charges but +nonpolar molecules are + + align:start position:0% +nonpolar molecules are + + + align:start position:0% +nonpolar molecules are +attracted by fluctuations + + align:start position:0% + + + + align:start position:0% + +fluctuations i should say + + align:start position:0% +fluctuations i should say + + + align:start position:0% +fluctuations i should say +by dipole fluctuations that's really + + align:start position:0% +by dipole fluctuations that's really + + + align:start position:0% +by dipole fluctuations that's really +what's happening + + align:start position:0% +what's happening + + + align:start position:0% +what's happening +right by dipole flux so so one of them + + align:start position:0% +right by dipole flux so so one of them + + + align:start position:0% +right by dipole flux so so one of them +gets a little shift and it's + + align:start position:0% +gets a little shift and it's + + + align:start position:0% +gets a little shift and it's +there's a dipole and then that dipole if + + align:start position:0% +there's a dipole and then that dipole if + + + align:start position:0% +there's a dipole and then that dipole if +there's another one around can induce + + align:start position:0% +there's another one around can induce + + + align:start position:0% +there's another one around can induce +a shift and then there can be a bond and + + align:start position:0% +a shift and then there can be a bond and + + + align:start position:0% +a shift and then there can be a bond and +now + + align:start position:0% +now + + + align:start position:0% +now +um this gets back to something very + + align:start position:0% +um this gets back to something very + + + align:start position:0% +um this gets back to something very +important + + align:start position:0% +important + + + align:start position:0% +important +which is that + + align:start position:0% +which is that + + + align:start position:0% +which is that +you can imagine how + + align:start position:0% +you can imagine how + + + align:start position:0% +you can imagine how +easy was it for temperature how easy was + + align:start position:0% +easy was it for temperature how easy was + + + align:start position:0% +easy was it for temperature how easy was +it + + align:start position:0% +it + + + align:start position:0% +it +to create that shift right well + + align:start position:0% +to create that shift right well + + + align:start position:0% +to create that shift right well +that's gonna have to do with your + + align:start position:0% +that's gonna have to do with your + + + align:start position:0% +that's gonna have to do with your +polarizability + + align:start position:0% +polarizability + + + align:start position:0% +polarizability +okay and now what okay so what what is + + align:start position:0% +okay and now what okay so what what is + + + align:start position:0% +okay and now what okay so what what is +it that has to do with polarizability + + align:start position:0% +it that has to do with polarizability + + + align:start position:0% +it that has to do with polarizability +right well if um i do have a board here + + align:start position:0% +right well if um i do have a board here + + + align:start position:0% +right well if um i do have a board here +ha okay + + align:start position:0% + + + + align:start position:0% + +you can you can already imagine if i go + + align:start position:0% +you can you can already imagine if i go + + + align:start position:0% +you can you can already imagine if i go +back to this list here + + align:start position:0% +back to this list here + + + align:start position:0% +back to this list here +now if i go from helium to argon what + + align:start position:0% +now if i go from helium to argon what + + + align:start position:0% +now if i go from helium to argon what +have i done i've gone down + + align:start position:0% +have i done i've gone down + + + align:start position:0% +have i done i've gone down +in the periodic table and we've already + + align:start position:0% +in the periodic table and we've already + + + align:start position:0% +in the periodic table and we've already +talked about this those electrons + + align:start position:0% +talked about this those electrons + + + align:start position:0% +talked about this those electrons +that are going to do the shifting to + + align:start position:0% +that are going to do the shifting to + + + align:start position:0% +that are going to do the shifting to +cause the fluctuation + + align:start position:0% +cause the fluctuation + + + align:start position:0% +cause the fluctuation +those electrons are more loosely bound + + align:start position:0% +those electrons are more loosely bound + + + align:start position:0% +those electrons are more loosely bound +right they're further out they're more + + align:start position:0% +right they're further out they're more + + + align:start position:0% +right they're further out they're more +loosely bound + + align:start position:0% +loosely bound + + + align:start position:0% +loosely bound +we've already talked about this we + + align:start position:0% +we've already talked about this we + + + align:start position:0% +we've already talked about this we +looked at this in a lot of ways right + + align:start position:0% +looked at this in a lot of ways right + + + align:start position:0% +looked at this in a lot of ways right +whether it's radius or ionization energy + + align:start position:0% +whether it's radius or ionization energy + + + align:start position:0% +whether it's radius or ionization energy +those are if they're more loosely bound + + align:start position:0% +those are if they're more loosely bound + + + align:start position:0% +those are if they're more loosely bound +then they're easier to shift around i'm + + align:start position:0% +then they're easier to shift around i'm + + + align:start position:0% +then they're easier to shift around i'm +not taking them out + + align:start position:0% +not taking them out + + + align:start position:0% +not taking them out +all right i'm not taking them out but + + align:start position:0% +all right i'm not taking them out but + + + align:start position:0% +all right i'm not taking them out but +i'm moving them that's what london + + align:start position:0% +i'm moving them that's what london + + + align:start position:0% +i'm moving them that's what london +is right i got to fluctuate it so you + + align:start position:0% +is right i got to fluctuate it so you + + + align:start position:0% +is right i got to fluctuate it so you +can imagine now why + + align:start position:0% +can imagine now why + + + align:start position:0% +can imagine now why +if it's heavier and those electrons are + + align:start position:0% +if it's heavier and those electrons are + + + align:start position:0% +if it's heavier and those electrons are +further out they're more polarizable + + align:start position:0% +further out they're more polarizable + + + align:start position:0% +further out they're more polarizable +right so let's write that down right so + + align:start position:0% +right so let's write that down right so + + + align:start position:0% +right so let's write that down right so +the london + + align:start position:0% +the london + + + align:start position:0% +the london +so we're going to get a stronger + + align:start position:0% +so we're going to get a stronger + + + align:start position:0% +so we're going to get a stronger +stronger london + + align:start position:0% +stronger london + + + align:start position:0% +stronger london +two reasons one + + align:start position:0% + + + + align:start position:0% + +heavier atom + + align:start position:0% +heavier atom + + + align:start position:0% +heavier atom +which really in this case right it's + + align:start position:0% +which really in this case right it's + + + align:start position:0% +which really in this case right it's +heavier but it really just means more + + align:start position:0% +heavier but it really just means more + + + align:start position:0% +heavier but it really just means more +polarizable + + align:start position:0% +polarizable + + + align:start position:0% +polarizable +if it's more polarizable that's the key + + align:start position:0% +if it's more polarizable that's the key + + + align:start position:0% +if it's more polarizable that's the key +that's the chemistry key more + + align:start position:0% +that's the chemistry key more + + + align:start position:0% +that's the chemistry key more +polarizable + + align:start position:0% +polarizable + + + align:start position:0% +polarizable +more polarizable electron cloud write it + + align:start position:0% +more polarizable electron cloud write it + + + align:start position:0% +more polarizable electron cloud write it +all out but the other thing that you can + + align:start position:0% +all out but the other thing that you can + + + align:start position:0% +all out but the other thing that you can +imagine with london + + align:start position:0% +imagine with london + + + align:start position:0% +imagine with london +right so that explains that trend the + + align:start position:0% +right so that explains that trend the + + + align:start position:0% +right so that explains that trend the +other thing that you can imagine with + + align:start position:0% +other thing that you can imagine with + + + align:start position:0% +other thing that you can imagine with +london is that + + align:start position:0% +london is that + + + align:start position:0% +london is that +these these uh interactions these + + align:start position:0% +these these uh interactions these + + + align:start position:0% +these these uh interactions these +fluctuations they're happening + + align:start position:0% +fluctuations they're happening + + + align:start position:0% +fluctuations they're happening +all over the place and the more contact + + align:start position:0% +all over the place and the more contact + + + align:start position:0% +all over the place and the more contact +i have the more places in a molecule i + + align:start position:0% +i have the more places in a molecule i + + + align:start position:0% +i have the more places in a molecule i +have + + align:start position:0% +have + + + align:start position:0% +have +to induce this to have this fluctuation + + align:start position:0% +to induce this to have this fluctuation + + + align:start position:0% +to induce this to have this fluctuation +happen the stronger these forces could + + align:start position:0% +happen the stronger these forces could + + + align:start position:0% +happen the stronger these forces could +be + + align:start position:0% +be + + + align:start position:0% +be +and this is exactly what we see look at + + align:start position:0% +and this is exactly what we see look at + + + align:start position:0% +and this is exactly what we see look at +this trend methane + + align:start position:0% +this trend methane + + + align:start position:0% +this trend methane +ethane propane and butane all i've done + + align:start position:0% +ethane propane and butane all i've done + + + align:start position:0% +ethane propane and butane all i've done +is i've added another carbon atom oh + + align:start position:0% +is i've added another carbon atom oh + + + align:start position:0% +is i've added another carbon atom oh +we're going to get to these + + align:start position:0% +we're going to get to these + + + align:start position:0% +we're going to get to these +we'll talk a little bit about orgo later + + align:start position:0% +we'll talk a little bit about orgo later + + + align:start position:0% +we'll talk a little bit about orgo later +but for now + + align:start position:0% +but for now + + + align:start position:0% +but for now +look at the boiling points of those + + align:start position:0% +look at the boiling points of those + + + align:start position:0% +look at the boiling points of those +again boiling point being a proxy + + align:start position:0% +again boiling point being a proxy + + + align:start position:0% +again boiling point being a proxy +for the bonding strength what bond could + + align:start position:0% +for the bonding strength what bond could + + + align:start position:0% +for the bonding strength what bond could +they have + + align:start position:0% +they have + + + align:start position:0% +they have +none of those only this + + align:start position:0% +none of those only this + + + align:start position:0% +none of those only this +huh i got excited only london + + align:start position:0% +huh i got excited only london + + + align:start position:0% +huh i got excited only london +because look they're non-polar molecules + + align:start position:0% +because look they're non-polar molecules + + + align:start position:0% +because look they're non-polar molecules +they got no charge on them this is the + + align:start position:0% +they got no charge on them this is the + + + align:start position:0% +they got no charge on them this is the +only way they can talk to each other + + align:start position:0% +only way they can talk to each other + + + align:start position:0% +only way they can talk to each other +but look at how much they talk to each + + align:start position:0% +but look at how much they talk to each + + + align:start position:0% +but look at how much they talk to each +other now why because of the second + + align:start position:0% +other now why because of the second + + + align:start position:0% +other now why because of the second +thing right which is that + + align:start position:0% +thing right which is that + + + align:start position:0% +thing right which is that +the greater the surface the greater the + + align:start position:0% +the greater the surface the greater the + + + align:start position:0% +the greater the surface the greater the +surface + + align:start position:0% +surface + + + align:start position:0% +surface +you can have more the more surface you + + align:start position:0% +you can have more the more surface you + + + align:start position:0% +you can have more the more surface you +have + + align:start position:0% +have + + + align:start position:0% +have +the greater surface + + align:start position:0% + + + + align:start position:0% + +more contact area more contact area + + align:start position:0% + + + + align:start position:0% + +and that's how this bond that's how this + + align:start position:0% +and that's how this bond that's how this + + + align:start position:0% +and that's how this bond that's how this +thing works + + align:start position:0% +thing works + + + align:start position:0% +thing works +because you can have you know as as long + + align:start position:0% +because you can have you know as as long + + + align:start position:0% +because you can have you know as as long +as i've got + + align:start position:0% +as i've got + + + align:start position:0% +as i've got +more surfaces seeing each other then + + align:start position:0% +more surfaces seeing each other then + + + align:start position:0% +more surfaces seeing each other then +there can be more fluctuations + + align:start position:0% +there can be more fluctuations + + + align:start position:0% +there can be more fluctuations +right that are happening that then + + align:start position:0% +right that are happening that then + + + align:start position:0% +right that are happening that then +induce the other one to have a + + align:start position:0% +induce the other one to have a + + + align:start position:0% +induce the other one to have a +fluctuation + + align:start position:0% +fluctuation + + + align:start position:0% +fluctuation +that then create a little moment of + + align:start position:0% +that then create a little moment of + + + align:start position:0% +that then create a little moment of +bonding + + align:start position:0% +bonding + + + align:start position:0% +bonding +that dramatically changes the properties + + align:start position:0% +that dramatically changes the properties + + + align:start position:0% +that dramatically changes the properties +and look at this this is a little bit + + align:start position:0% +and look at this this is a little bit + + + align:start position:0% +and look at this this is a little bit +small but + + align:start position:0% +small but + + + align:start position:0% +small but +you know these are the so let's you know + + align:start position:0% +you know these are the so let's you know + + + align:start position:0% +you know these are the so let's you know +go all the way right ch4 + + align:start position:0% +go all the way right ch4 + + + align:start position:0% +go all the way right ch4 +c2a okay let's go all the way and look + + align:start position:0% +c2a okay let's go all the way and look + + + align:start position:0% +c2a okay let's go all the way and look +at this it determines + + align:start position:0% +at this it determines + + + align:start position:0% +at this it determines +when you have a gas at room temperature + + align:start position:0% +when you have a gas at room temperature + + + align:start position:0% +when you have a gas at room temperature +or when you have a liquid + + align:start position:0% +or when you have a liquid + + + align:start position:0% +or when you have a liquid +at room temperature boy is that + + align:start position:0% +at room temperature boy is that + + + align:start position:0% +at room temperature boy is that +important for how we + + align:start position:0% +important for how we + + + align:start position:0% +important for how we +use these molecules right boy is that + + align:start position:0% +use these molecules right boy is that + + + align:start position:0% +use these molecules right boy is that +important + + align:start position:0% +important + + + align:start position:0% +important +it's all london there's no other option + + align:start position:0% +it's all london there's no other option + + + align:start position:0% +it's all london there's no other option +right but that's what's dictating this + + align:start position:0% +right but that's what's dictating this + + + align:start position:0% +right but that's what's dictating this +trend but it's even more + + align:start position:0% +trend but it's even more + + + align:start position:0% +trend but it's even more +mind-blowing than that because look at + + align:start position:0% +mind-blowing than that because look at + + + align:start position:0% +mind-blowing than that because look at +this this is one + + align:start position:0% +this this is one + + + align:start position:0% +this this is one +molecule that's identical + + align:start position:0% +molecule that's identical + + + align:start position:0% +molecule that's identical +this is c5 this is the five atoms of + + align:start position:0% +this is c5 this is the five atoms of + + + align:start position:0% +this is c5 this is the five atoms of +carbon + + align:start position:0% +carbon + + + align:start position:0% +carbon +and pentane same exact grams per mole + + align:start position:0% +and pentane same exact grams per mole + + + align:start position:0% +and pentane same exact grams per mole +because it's the same chemical formula + + align:start position:0% +because it's the same chemical formula + + + align:start position:0% +because it's the same chemical formula +but look here + + align:start position:0% +but look here + + + align:start position:0% +but look here +36.1 degrees c is the boiling point here + + align:start position:0% +36.1 degrees c is the boiling point here + + + align:start position:0% +36.1 degrees c is the boiling point here +it's 9.5 + + align:start position:0% +it's 9.5 + + + align:start position:0% +it's 9.5 +why it's all this this is not the ground + + align:start position:0% +why it's all this this is not the ground + + + align:start position:0% +why it's all this this is not the ground +state + + align:start position:0% +state + + + align:start position:0% +state +this is the most stable structure is + + align:start position:0% +this is the most stable structure is + + + align:start position:0% +this is the most stable structure is +here but there is a version that's + + align:start position:0% +here but there is a version that's + + + align:start position:0% +here but there is a version that's +called neopentane + + align:start position:0% +called neopentane + + + align:start position:0% +called neopentane +it's like a nickname for it there's a + + align:start position:0% +it's like a nickname for it there's a + + + align:start position:0% +it's like a nickname for it there's a +version of it that you can make + + align:start position:0% +version of it that you can make + + + align:start position:0% +version of it that you can make +that has a different shape and because + + align:start position:0% +that has a different shape and because + + + align:start position:0% +that has a different shape and because +this shape cannot come into contact with + + align:start position:0% +this shape cannot come into contact with + + + align:start position:0% +this shape cannot come into contact with +itself look at this + + align:start position:0% +itself look at this + + + align:start position:0% +itself look at this +you can see it from the red line it's + + align:start position:0% +you can see it from the red line it's + + + align:start position:0% +you can see it from the red line it's +coming into contact with itself + + align:start position:0% +coming into contact with itself + + + align:start position:0% +coming into contact with itself +in the liquid or gas it can't have as + + align:start position:0% +in the liquid or gas it can't have as + + + align:start position:0% +in the liquid or gas it can't have as +much london + + align:start position:0% +much london + + + align:start position:0% +much london +forces london potential so it cannot + + align:start position:0% +forces london potential so it cannot + + + align:start position:0% +forces london potential so it cannot +bind as strongly and therefore the + + align:start position:0% +bind as strongly and therefore the + + + align:start position:0% +bind as strongly and therefore the +boiling point is a lot lower + + align:start position:0% +boiling point is a lot lower + + + align:start position:0% +boiling point is a lot lower +right this is a lot lower now + + align:start position:0% +right this is a lot lower now + + + align:start position:0% +right this is a lot lower now +there's a little bit of naming confusion + + align:start position:0% +there's a little bit of naming confusion + + + align:start position:0% +there's a little bit of naming confusion +i want to clear this up oh boy + + align:start position:0% +i want to clear this up oh boy + + + align:start position:0% +i want to clear this up oh boy +nowhere to go here so i'm going to get + + align:start position:0% +nowhere to go here so i'm going to get + + + align:start position:0% +nowhere to go here so i'm going to get +rid of london for a sec + + align:start position:0% +rid of london for a sec + + + align:start position:0% +rid of london for a sec +and i want to make something very clear + + align:start position:0% +and i want to make something very clear + + + align:start position:0% +and i want to make something very clear +that there's another word that's used + + align:start position:0% +that there's another word that's used + + + align:start position:0% +that there's another word that's used +which is called van der waals okay now + + align:start position:0% +which is called van der waals okay now + + + align:start position:0% +which is called van der waals okay now +this ability of a fluctuation to happen + + align:start position:0% +this ability of a fluctuation to happen + + + align:start position:0% +this ability of a fluctuation to happen +which then induces a fluctuation that + + align:start position:0% +which then induces a fluctuation that + + + align:start position:0% +which then induces a fluctuation that +can happen no matter + + align:start position:0% +can happen no matter + + + align:start position:0% +can happen no matter +what molecule you have it can happen and + + align:start position:0% +what molecule you have it can happen and + + + align:start position:0% +what molecule you have it can happen and +it does + + align:start position:0% +it does + + + align:start position:0% +it does +it's always there right so all molecules + + align:start position:0% +it's always there right so all molecules + + + align:start position:0% +it's always there right so all molecules +all molecules + + align:start position:0% + + + + align:start position:0% + +whether they're polar or nonpolar polar + + align:start position:0% +whether they're polar or nonpolar polar + + + align:start position:0% +whether they're polar or nonpolar polar +or nonpolar + + align:start position:0% + + + + align:start position:0% + +all molecules are attracted + + align:start position:0% +all molecules are attracted + + + align:start position:0% +all molecules are attracted +by london + + align:start position:0% + + + + align:start position:0% + +plus any other attractive forces + + align:start position:0% +plus any other attractive forces + + + align:start position:0% +plus any other attractive forces +any other attractive forces present + + align:start position:0% + + + + align:start position:0% + +force is present okay so that's so + + align:start position:0% +force is present okay so that's so + + + align:start position:0% +force is present okay so that's so +london is always there + + align:start position:0% +london is always there + + + align:start position:0% +london is always there +now people interchangeably + + align:start position:0% +now people interchangeably + + + align:start position:0% +now people interchangeably +use the term vanderballs + + align:start position:0% + + + + align:start position:0% + +and what van der waals encompasses + + align:start position:0% +and what van der waals encompasses + + + align:start position:0% +and what van der waals encompasses +is more than london + + align:start position:0% +is more than london + + + align:start position:0% +is more than london +so vanderballs which you will sometimes + + align:start position:0% +so vanderballs which you will sometimes + + + align:start position:0% +so vanderballs which you will sometimes +see in textbooks + + align:start position:0% +see in textbooks + + + align:start position:0% +see in textbooks +is the van der waals force + + align:start position:0% + + + + align:start position:0% + +okay so that is any + + align:start position:0% + + + + align:start position:0% + +or all added + + align:start position:0% +or all added + + + align:start position:0% +or all added +together this is the combination of + + align:start position:0% +together this is the combination of + + + align:start position:0% +together this is the combination of +these weak forces + + align:start position:0% +these weak forces + + + align:start position:0% +these weak forces +of dipole dipole + + align:start position:0% +of dipole dipole + + + align:start position:0% +of dipole dipole +dipole dipole + + align:start position:0% +dipole dipole + + + align:start position:0% +dipole dipole +let's see dipole + + align:start position:0% + + + + align:start position:0% + +induced dipole + + align:start position:0% +induced dipole + + + align:start position:0% +induced dipole +and london + + align:start position:0% + + + + align:start position:0% + +those taken together those taken + + align:start position:0% +those taken together those taken + + + align:start position:0% +those taken together those taken +together + + align:start position:0% +together + + + align:start position:0% +together +you will sometimes see referred to as + + align:start position:0% +you will sometimes see referred to as + + + align:start position:0% +you will sometimes see referred to as +van der waals forces + + align:start position:0% +van der waals forces + + + align:start position:0% +van der waals forces +or weak forces but we know more than + + align:start position:0% +or weak forces but we know more than + + + align:start position:0% +or weak forces but we know more than +that + + align:start position:0% +that + + + align:start position:0% +that +we know the distinction + + align:start position:0% +we know the distinction + + + align:start position:0% +we know the distinction +we know that london started like this + + align:start position:0% +we know that london started like this + + + align:start position:0% +we know that london started like this +and then went like this + + align:start position:0% + + + + align:start position:0% + +ah really bad goes in tight + + align:start position:0% +ah really bad goes in tight + + + align:start position:0% +ah really bad goes in tight +right we know that it started with + + align:start position:0% +right we know that it started with + + + align:start position:0% +right we know that it started with +non-polar and that there's a difference + + align:start position:0% +non-polar and that there's a difference + + + align:start position:0% +non-polar and that there's a difference +and so this is + + align:start position:0% +and so this is + + + align:start position:0% +and so this is +all about the polarizable electron cloud + + align:start position:0% +all about the polarizable electron cloud + + + align:start position:0% +all about the polarizable electron cloud +polarizable electron cloud that's all + + align:start position:0% +polarizable electron cloud that's all + + + align:start position:0% +polarizable electron cloud that's all +you got + + align:start position:0% + + + + align:start position:0% + +right and this can be really small 0.5 + + align:start position:0% +right and this can be really small 0.5 + + + align:start position:0% +right and this can be really small 0.5 +to 40. oh yeah let's just keep with + + align:start position:0% +to 40. oh yeah let's just keep with + + + align:start position:0% +to 40. oh yeah let's just keep with +chlorine two + + align:start position:0% +chlorine two + + + align:start position:0% +chlorine two +chlorine two two non-polar molecules + + align:start position:0% +chlorine two two non-polar molecules + + + align:start position:0% +chlorine two two non-polar molecules +london dispersion and this also has a + + align:start position:0% +london dispersion and this also has a + + + align:start position:0% +london dispersion and this also has a +dependence of + + align:start position:0% +dependence of + + + align:start position:0% +dependence of +in terms of the distance of one over r + + align:start position:0% +in terms of the distance of one over r + + + align:start position:0% +in terms of the distance of one over r +to the sixth now in case you think + + align:start position:0% +to the sixth now in case you think + + + align:start position:0% +to the sixth now in case you think +that's small + + align:start position:0% +that's small + + + align:start position:0% +that's small +i wanna show you a little video of why + + align:start position:0% +i wanna show you a little video of why + + + align:start position:0% +i wanna show you a little video of why +this matters so + + align:start position:0% +this matters so + + + align:start position:0% +this matters so +weak forces now weak forces are really + + align:start position:0% +weak forces now weak forces are really + + + align:start position:0% +weak forces now weak forces are really +strong we know this + + align:start position:0% +strong we know this + + + align:start position:0% +strong we know this +because of mission impossible we know + + align:start position:0% +because of mission impossible we know + + + align:start position:0% +because of mission impossible we know +this + + align:start position:0% +this + + + align:start position:0% +this +also because of our own students there + + align:start position:0% +also because of our own students there + + + align:start position:0% +also because of our own students there +was one of my former students rory + + align:start position:0% +was one of my former students rory + + + align:start position:0% +was one of my former students rory +and he won all sorts of prizes because + + align:start position:0% +and he won all sorts of prizes because + + + align:start position:0% +and he won all sorts of prizes because +he was trying to be like a gecko + + align:start position:0% +he was trying to be like a gecko + + + align:start position:0% +he was trying to be like a gecko +and so he made gloves that were like + + align:start position:0% +and so he made gloves that were like + + + align:start position:0% +and so he made gloves that were like +gecko gloves and much to the delight + + align:start position:0% +gecko gloves and much to the delight + + + align:start position:0% +gecko gloves and much to the delight +of the facilities people at mit he + + align:start position:0% +of the facilities people at mit he + + + align:start position:0% +of the facilities people at mit he +actually climbed + + align:start position:0% +actually climbed + + + align:start position:0% +actually climbed +one of the buildings using these his + + align:start position:0% +one of the buildings using these his + + + align:start position:0% +one of the buildings using these his +gloves + + align:start position:0% +gloves + + + align:start position:0% +gloves +in case you are wondering it wasn't + + align:start position:0% +in case you are wondering it wasn't + + + align:start position:0% +in case you are wondering it wasn't +actually their delight + + align:start position:0% +actually their delight + + + align:start position:0% +actually their delight +um but uh but it really cool stuff so + + align:start position:0% +um but uh but it really cool stuff so + + + align:start position:0% +um but uh but it really cool stuff so +let me show you just this is like a 30 + + align:start position:0% +let me show you just this is like a 30 + + + align:start position:0% +let me show you just this is like a 30 +second video + + align:start position:0% +second video + + + align:start position:0% +second video +he found the answer in the sheer number + + align:start position:0% +he found the answer in the sheer number + + + align:start position:0% +he found the answer in the sheer number +and design + + align:start position:0% +and design + + + align:start position:0% +and design +of the hairs on the gecko's feet + + align:start position:0% +of the hairs on the gecko's feet + + + align:start position:0% +of the hairs on the gecko's feet +geckos have millions of microscopic + + align:start position:0% +geckos have millions of microscopic + + + align:start position:0% +geckos have millions of microscopic +hairs on their toes + + align:start position:0% +hairs on their toes + + + align:start position:0% +hairs on their toes +of course we can't see this with our + + align:start position:0% +of course we can't see this with our + + + align:start position:0% +of course we can't see this with our +naked eye because each hair is only one + + align:start position:0% +naked eye because each hair is only one + + + align:start position:0% +naked eye because each hair is only one +tenth the size of a human hair + + align:start position:0% +tenth the size of a human hair + + + align:start position:0% +tenth the size of a human hair +and each of those hairs branch down to + + align:start position:0% +and each of those hairs branch down to + + + align:start position:0% +and each of those hairs branch down to +billions of little split ends + + align:start position:0% +billions of little split ends + + + align:start position:0% +billions of little split ends +and they can make such close contact + + align:start position:0% +and they can make such close contact + + + align:start position:0% +and they can make such close contact +with the surface that + + align:start position:0% +with the surface that + + + align:start position:0% +with the surface that +weak intermolecular forces can begin to + + align:start position:0% +weak intermolecular forces can begin to + + + align:start position:0% +weak intermolecular forces can begin to +add up to something really strong + + align:start position:0% + + + + align:start position:0% + +turns out geckos exploit something + + align:start position:0% +turns out geckos exploit something + + + align:start position:0% +turns out geckos exploit something +called the van der waals force + + align:start position:0% +called the van der waals force + + + align:start position:0% +called the van der waals force +no london london if you think of an atom + + align:start position:0% +no london london if you think of an atom + + + align:start position:0% +no london london if you think of an atom +as a dancing couple + + align:start position:0% +as a dancing couple + + + align:start position:0% +as a dancing couple +when you bring two atoms into very close + + align:start position:0% +when you bring two atoms into very close + + + align:start position:0% +when you bring two atoms into very close +contact + + align:start position:0% +contact + + + align:start position:0% +contact +part of one atom can get attracted to + + align:start position:0% +part of one atom can get attracted to + + + align:start position:0% +part of one atom can get attracted to +part of the other + + align:start position:0% +part of the other + + + align:start position:0% +part of the other +that very weak bond is the van der waals + + align:start position:0% +that very weak bond is the van der waals + + + align:start position:0% +that very weak bond is the van der waals +force + + align:start position:0% +force + + + align:start position:0% +force +and it sticks atoms together proximity + + align:start position:0% +and it sticks atoms together proximity + + + align:start position:0% +and it sticks atoms together proximity +is the key + + align:start position:0% +is the key + + + align:start position:0% +is the key +but bringing two materials that near + + align:start position:0% +but bringing two materials that near + + + align:start position:0% +but bringing two materials that near +each other is harder than you'd think + + align:start position:0% +each other is harder than you'd think + + + align:start position:0% +each other is harder than you'd think +all right now obviously + + align:start position:0% +all right now obviously + + + align:start position:0% +all right now obviously +that got me very excited when i saw that + + align:start position:0% +that got me very excited when i saw that + + + align:start position:0% +that got me very excited when i saw that +um + + align:start position:0% +um + + + align:start position:0% +um +because that is how i see atoms and that + + align:start position:0% +because that is how i see atoms and that + + + align:start position:0% +because that is how i see atoms and that +is how i see electrons and i saw this + + align:start position:0% +is how i see electrons and i saw this + + + align:start position:0% +is how i see electrons and i saw this +and i almost fell over + + align:start position:0% +and i almost fell over + + + align:start position:0% +and i almost fell over +and uh and of course i've played it and + + align:start position:0% +and uh and of course i've played it and + + + align:start position:0% +and uh and of course i've played it and +i know all those moves i would suggest + + align:start position:0% +i know all those moves i would suggest + + + align:start position:0% +i know all those moves i would suggest +you guys + + align:start position:0% +you guys + + + align:start position:0% +you guys +it's a friday there's some good moves in + + align:start position:0% +it's a friday there's some good moves in + + + align:start position:0% +it's a friday there's some good moves in +there + + align:start position:0% +there + + + align:start position:0% +there +there's some good moves in there and you + + align:start position:0% +there's some good moves in there and you + + + align:start position:0% +there's some good moves in there and you +can take this on your phone and just + + align:start position:0% +can take this on your phone and just + + + align:start position:0% +can take this on your phone and just +kind of work it out at the club + + align:start position:0% +kind of work it out at the club + + + align:start position:0% +kind of work it out at the club +um and speaking of the club there's one + + align:start position:0% +um and speaking of the club there's one + + + align:start position:0% +um and speaking of the club there's one +more thing i got to teach you + + align:start position:0% +more thing i got to teach you + + + align:start position:0% +more thing i got to teach you +because it's that last line it's that + + align:start position:0% +because it's that last line it's that + + + align:start position:0% +because it's that last line it's that +last line + + align:start position:0% +last line + + + align:start position:0% +last line +um see um if you go along a trend + + align:start position:0% +um see um if you go along a trend + + + align:start position:0% +um see um if you go along a trend +like methane silane germany right these + + align:start position:0% +like methane silane germany right these + + + align:start position:0% +like methane silane germany right these +are all attract these are non-polar + + align:start position:0% +are all attract these are non-polar + + + align:start position:0% +are all attract these are non-polar +molecules + + align:start position:0% +molecules + + + align:start position:0% +molecules +they're all attracted uh to each other + + align:start position:0% +they're all attracted uh to each other + + + align:start position:0% +they're all attracted uh to each other +by these van der waals and you can see + + align:start position:0% +by these van der waals and you can see + + + align:start position:0% +by these van der waals and you can see +that + + align:start position:0% +that + + + align:start position:0% +that +the boiling point remember our proxy for + + align:start position:0% +the boiling point remember our proxy for + + + align:start position:0% +the boiling point remember our proxy for +the force the the bonding strength + + align:start position:0% +the force the the bonding strength + + + align:start position:0% +the force the the bonding strength +is going up that's what you'd expect + + align:start position:0% +is going up that's what you'd expect + + + align:start position:0% +is going up that's what you'd expect +that's because these are getting larger + + align:start position:0% +that's because these are getting larger + + + align:start position:0% +that's because these are getting larger +and they're going to be + + align:start position:0% +and they're going to be + + + align:start position:0% +and they're going to be +more polarizable electrons yeah but look + + align:start position:0% +more polarizable electrons yeah but look + + + align:start position:0% +more polarizable electrons yeah but look +at what happens + + align:start position:0% +at what happens + + + align:start position:0% +at what happens +as you go to other molecules this is the + + align:start position:0% +as you go to other molecules this is the + + + align:start position:0% +as you go to other molecules this is the +expected trend + + align:start position:0% +expected trend + + + align:start position:0% +expected trend +until you get here right nh3hf + + align:start position:0% +until you get here right nh3hf + + + align:start position:0% +until you get here right nh3hf +and that is because of one last type of + + align:start position:0% +and that is because of one last type of + + + align:start position:0% +and that is because of one last type of +bond that is because + + align:start position:0% +bond that is because + + + align:start position:0% +bond that is because +of something called a hydrogen bond it's + + align:start position:0% +of something called a hydrogen bond it's + + + align:start position:0% +of something called a hydrogen bond it's +a very unique + + align:start position:0% +a very unique + + + align:start position:0% +a very unique +uh kind of bond and so a hydrogen bond + + align:start position:0% +uh kind of bond and so a hydrogen bond + + + align:start position:0% +uh kind of bond and so a hydrogen bond +is our last intermolecular bond in + + align:start position:0% +is our last intermolecular bond in + + + align:start position:0% +is our last intermolecular bond in +hydrogen bond + + align:start position:0% + + + + align:start position:0% + +right and it's a very particular kind of + + align:start position:0% +right and it's a very particular kind of + + + align:start position:0% +right and it's a very particular kind of +bond and it has to do with something + + align:start position:0% +bond and it has to do with something + + + align:start position:0% +bond and it has to do with something +very particular that hydrogen does + + align:start position:0% +very particular that hydrogen does + + + align:start position:0% +very particular that hydrogen does +look at those boiling points look at the + + align:start position:0% +look at those boiling points look at the + + + align:start position:0% +look at those boiling points look at the +change i mean + + align:start position:0% +change i mean + + + align:start position:0% +change i mean +h2o is h2o because of the hydrogen bond + + align:start position:0% +h2o is h2o because of the hydrogen bond + + + align:start position:0% +h2o is h2o because of the hydrogen bond +right earth's operating conditions + + align:start position:0% +right earth's operating conditions + + + align:start position:0% +right earth's operating conditions +uh are luckily right here but this is + + align:start position:0% +uh are luckily right here but this is + + + align:start position:0% +uh are luckily right here but this is +only + + align:start position:0% +only + + + align:start position:0% +only +good because of hydrogen bonds that it's + + align:start position:0% +good because of hydrogen bonds that it's + + + align:start position:0% +good because of hydrogen bonds that it's +all the way up here and not all the way + + align:start position:0% +all the way up here and not all the way + + + align:start position:0% +all the way up here and not all the way +down there + + align:start position:0% +down there + + + align:start position:0% +down there +yeah so hydrogen bonds are unique this + + align:start position:0% +yeah so hydrogen bonds are unique this + + + align:start position:0% +yeah so hydrogen bonds are unique this +is the electro negativity scale + + align:start position:0% +is the electro negativity scale + + + align:start position:0% +is the electro negativity scale +and there's something very important + + align:start position:0% +and there's something very important + + + align:start position:0% +and there's something very important +that happens for those three elements + + align:start position:0% +that happens for those three elements + + + align:start position:0% +that happens for those three elements +for those three elements those are the + + align:start position:0% +for those three elements those are the + + + align:start position:0% +for those three elements those are the +three elements that are in this trend + + align:start position:0% +three elements that are in this trend + + + align:start position:0% +three elements that are in this trend +those are the three elements see + + align:start position:0% +those are the three elements see + + + align:start position:0% +those are the three elements see +nitrogen chlorine and oxygen + + align:start position:0% +nitrogen chlorine and oxygen + + + align:start position:0% +nitrogen chlorine and oxygen +those are the three elements here and + + align:start position:0% +those are the three elements here and + + + align:start position:0% +those are the three elements here and +what's important about them is that they + + align:start position:0% +what's important about them is that they + + + align:start position:0% +what's important about them is that they +have such a huge electronegativity + + align:start position:0% +have such a huge electronegativity + + + align:start position:0% +have such a huge electronegativity +and so in a hydrogen bond what's going + + align:start position:0% +and so in a hydrogen bond what's going + + + align:start position:0% +and so in a hydrogen bond what's going +to happen + + align:start position:0% +to happen + + + align:start position:0% +to happen +what's going to happen in a hydrogen + + align:start position:0% +what's going to happen in a hydrogen + + + align:start position:0% +what's going to happen in a hydrogen +bond is they're really going to pull a + + align:start position:0% +bond is they're really going to pull a + + + align:start position:0% +bond is they're really going to pull a +lot of charge + + align:start position:0% +lot of charge + + + align:start position:0% +lot of charge +from the hydrogen so if you have + + align:start position:0% +from the hydrogen so if you have + + + align:start position:0% +from the hydrogen so if you have +so you have a very high positive charge + + align:start position:0% +so you have a very high positive charge + + + align:start position:0% +so you have a very high positive charge +on the hydrogen but there's something + + align:start position:0% +on the hydrogen but there's something + + + align:start position:0% +on the hydrogen but there's something +else that happens + + align:start position:0% +else that happens + + + align:start position:0% +else that happens +for hydrogen bonding to occur you see + + align:start position:0% +for hydrogen bonding to occur you see + + + align:start position:0% +for hydrogen bonding to occur you see +it's the + + align:start position:0% +it's the + + + align:start position:0% +it's the +h with say fluorine + + align:start position:0% +h with say fluorine + + + align:start position:0% +h with say fluorine +and you have a delta plus and a delta + + align:start position:0% +and you have a delta plus and a delta + + + align:start position:0% +and you have a delta plus and a delta +minus and this is high + + align:start position:0% +minus and this is high + + + align:start position:0% +minus and this is high +this is very high right but you also + + align:start position:0% +this is very high right but you also + + + align:start position:0% +this is very high right but you also +have + + align:start position:0% +have + + + align:start position:0% +have +a lone pair somewhere you've also got a + + align:start position:0% +a lone pair somewhere you've also got a + + + align:start position:0% +a lone pair somewhere you've also got a +lone pair + + align:start position:0% +lone pair + + + align:start position:0% +lone pair +where we know that we have that on the + + align:start position:0% +where we know that we have that on the + + + align:start position:0% +where we know that we have that on the +flurry right + + align:start position:0% +flurry right + + + align:start position:0% +flurry right +we know that and we got those too and + + align:start position:0% +we know that and we got those too and + + + align:start position:0% +we know that and we got those too and +the bond that a hydrogen bond + + align:start position:0% +the bond that a hydrogen bond + + + align:start position:0% +the bond that a hydrogen bond +represents is the fact that i've done + + align:start position:0% +represents is the fact that i've done + + + align:start position:0% +represents is the fact that i've done +two things with this same molecule + + align:start position:0% +two things with this same molecule + + + align:start position:0% +two things with this same molecule +i've taken a lot of charge off of + + align:start position:0% +i've taken a lot of charge off of + + + align:start position:0% +i've taken a lot of charge off of +hydrogen and created a very strong + + align:start position:0% +hydrogen and created a very strong + + + align:start position:0% +hydrogen and created a very strong +delta plus on the hydrogen but i've also + + align:start position:0% +delta plus on the hydrogen but i've also + + + align:start position:0% +delta plus on the hydrogen but i've also +got a lone pair somewhere + + align:start position:0% +got a lone pair somewhere + + + align:start position:0% +got a lone pair somewhere +that that can bond to and when i have + + align:start position:0% +that that can bond to and when i have + + + align:start position:0% +that that can bond to and when i have +those two things + + align:start position:0% +those two things + + + align:start position:0% +those two things +which i really have for these three + + align:start position:0% +which i really have for these three + + + align:start position:0% +which i really have for these three +elements right when i have those two + + align:start position:0% +elements right when i have those two + + + align:start position:0% +elements right when i have those two +things + + align:start position:0% +things + + + align:start position:0% +things +i can make this very special kind of + + align:start position:0% +i can make this very special kind of + + + align:start position:0% +i can make this very special kind of +bond + + align:start position:0% +bond + + + align:start position:0% +bond +now um this is what it looks like right + + align:start position:0% +now um this is what it looks like right + + + align:start position:0% +now um this is what it looks like right +so there's there's a hi + + align:start position:0% +so there's there's a hi + + + align:start position:0% +so there's there's a hi +there's an h2o molecule and i want to + + align:start position:0% +there's an h2o molecule and i want to + + + align:start position:0% +there's an h2o molecule and i want to +make a point here + + align:start position:0% +make a point here + + + align:start position:0% +make a point here +right there's the covalent bond between + + align:start position:0% +right there's the covalent bond between + + + align:start position:0% +right there's the covalent bond between +the oxygen and the hydrogen + + align:start position:0% +the oxygen and the hydrogen + + + align:start position:0% +the oxygen and the hydrogen +there's the delta plus and there's that + + align:start position:0% +there's the delta plus and there's that + + + align:start position:0% +there's the delta plus and there's that +hydrogen bond right there + + align:start position:0% + + + + align:start position:0% + +there okay hydrogen bond that forms + + align:start position:0% +there okay hydrogen bond that forms + + + align:start position:0% +there okay hydrogen bond that forms +between the delta + + align:start position:0% +between the delta + + + align:start position:0% +between the delta +plus and the lone pair now you can see + + align:start position:0% +plus and the lone pair now you can see + + + align:start position:0% +plus and the lone pair now you can see +why water is so special + + align:start position:0% +why water is so special + + + align:start position:0% +why water is so special +you can see because unlike nh3 or hf + + align:start position:0% +you can see because unlike nh3 or hf + + + align:start position:0% +you can see because unlike nh3 or hf +you see why water had the biggest kick + + align:start position:0% +you see why water had the biggest kick + + + align:start position:0% +you see why water had the biggest kick +up + + align:start position:0% +up + + + align:start position:0% +up +from what would be expected because + + align:start position:0% +from what would be expected because + + + align:start position:0% +from what would be expected because +unlike nhh + + align:start position:0% +unlike nhh + + + align:start position:0% +unlike nhh +you have exactly the right balance + + align:start position:0% +you have exactly the right balance + + + align:start position:0% +you have exactly the right balance +i've created two of these very strong + + align:start position:0% +i've created two of these very strong + + + align:start position:0% +i've created two of these very strong +delta pluses and i've got two + + align:start position:0% +delta pluses and i've got two + + + align:start position:0% +delta pluses and i've got two +lone pairs and it all works out there's + + align:start position:0% +lone pairs and it all works out there's + + + align:start position:0% +lone pairs and it all works out there's +no extra lone pairs like here + + align:start position:0% +no extra lone pairs like here + + + align:start position:0% +no extra lone pairs like here +i've got these extra lone pairs right + + align:start position:0% +i've got these extra lone pairs right + + + align:start position:0% +i've got these extra lone pairs right +that don't don't there aren't enough + + align:start position:0% +that don't don't there aren't enough + + + align:start position:0% +that don't don't there aren't enough +moles you know each molecule only has + + align:start position:0% +moles you know each molecule only has + + + align:start position:0% +moles you know each molecule only has +one hydrogen here it's two and two + + align:start position:0% +one hydrogen here it's two and two + + + align:start position:0% +one hydrogen here it's two and two +that's why water is so special + + align:start position:0% +that's why water is so special + + + align:start position:0% +that's why water is so special +this bond is so important i know you've + + align:start position:0% +this bond is so important i know you've + + + align:start position:0% +this bond is so important i know you've +probably heard about it for water but + + align:start position:0% +probably heard about it for water but + + + align:start position:0% +probably heard about it for water but +here's my + + align:start position:0% +here's my + + + align:start position:0% +here's my +uh the example i want to give you for + + align:start position:0% +uh the example i want to give you for + + + align:start position:0% +uh the example i want to give you for +the club because some of you + + align:start position:0% +the club because some of you + + + align:start position:0% +the club because some of you +might be able to drink ethanol only if + + align:start position:0% +might be able to drink ethanol only if + + + align:start position:0% +might be able to drink ethanol only if +you're + + align:start position:0% +you're + + + align:start position:0% +you're +at the right age please of course + + align:start position:0% +at the right age please of course + + + align:start position:0% +at the right age please of course +um this is the but this is what's in + + align:start position:0% +um this is the but this is what's in + + + align:start position:0% +um this is the but this is what's in +alcohol right this is the ethanol + + align:start position:0% +alcohol right this is the ethanol + + + align:start position:0% +alcohol right this is the ethanol +molecule + + align:start position:0% +molecule + + + align:start position:0% +molecule +and it has a boiling point of 78.5 + + align:start position:0% +and it has a boiling point of 78.5 + + + align:start position:0% +and it has a boiling point of 78.5 +degrees again + + align:start position:0% +degrees again + + + align:start position:0% +degrees again +that tells you something about the bond + + align:start position:0% +that tells you something about the bond + + + align:start position:0% +that tells you something about the bond +strength of this molecule to another + + align:start position:0% +strength of this molecule to another + + + align:start position:0% +strength of this molecule to another +molecule + + align:start position:0% +molecule + + + align:start position:0% +molecule +but look at this that's an oxygen with a + + align:start position:0% +but look at this that's an oxygen with a + + + align:start position:0% +but look at this that's an oxygen with a +hydrogen + + align:start position:0% +hydrogen + + + align:start position:0% +hydrogen +this took a lot of charge from the + + align:start position:0% +this took a lot of charge from the + + + align:start position:0% +this took a lot of charge from the +hydrogen right so you got a strong delta + + align:start position:0% +hydrogen right so you got a strong delta + + + align:start position:0% +hydrogen right so you got a strong delta +plus but you've got those two lone pairs + + align:start position:0% +plus but you've got those two lone pairs + + + align:start position:0% +plus but you've got those two lone pairs +there + + align:start position:0% +there + + + align:start position:0% +there +ready to bond to the other ethanol + + align:start position:0% +ready to bond to the other ethanol + + + align:start position:0% +ready to bond to the other ethanol +molecule but look at what happens + + align:start position:0% +molecule but look at what happens + + + align:start position:0% +molecule but look at what happens +methoxy methane is a gas at room + + align:start position:0% +methoxy methane is a gas at room + + + align:start position:0% +methoxy methane is a gas at room +temperature + + align:start position:0% +temperature + + + align:start position:0% +temperature +it's boiled off it's the exact same + + align:start position:0% +it's boiled off it's the exact same + + + align:start position:0% +it's boiled off it's the exact same +chemical formula + + align:start position:0% +chemical formula + + + align:start position:0% +chemical formula +it's the exact same chemical formula all + + align:start position:0% +it's the exact same chemical formula all + + + align:start position:0% +it's the exact same chemical formula all +i've done is shift the oxygen in + + align:start position:0% +i've done is shift the oxygen in + + + align:start position:0% +i've done is shift the oxygen in +and so now there's no hydrogen that's + + align:start position:0% +and so now there's no hydrogen that's + + + align:start position:0% +and so now there's no hydrogen that's +that's had that big of a delta on it + + align:start position:0% +that's had that big of a delta on it + + + align:start position:0% +that's had that big of a delta on it +so it cannot hydrogen bond it can we can + + align:start position:0% +so it cannot hydrogen bond it can we can + + + align:start position:0% +so it cannot hydrogen bond it can we can +london + + align:start position:0% +london + + + align:start position:0% +london +you know but it can't hydrogen it can't + + align:start position:0% +you know but it can't hydrogen it can't + + + align:start position:0% +you know but it can't hydrogen it can't +because the oxygen has the lone pairs + + align:start position:0% +because the oxygen has the lone pairs + + + align:start position:0% +because the oxygen has the lone pairs +but there's no hydrogens + + align:start position:0% +but there's no hydrogens + + + align:start position:0% +but there's no hydrogens +that have that strong of a delta so when + + align:start position:0% +that have that strong of a delta so when + + + align:start position:0% +that have that strong of a delta so when +you're at the club tonight trying out + + align:start position:0% +you're at the club tonight trying out + + + align:start position:0% +you're at the club tonight trying out +those moves + + align:start position:0% +those moves + + + align:start position:0% +those moves +go up to somebody and say it's a really + + align:start position:0% +go up to somebody and say it's a really + + + align:start position:0% +go up to somebody and say it's a really +good thing that's not + + align:start position:0% +good thing that's not + + + align:start position:0% +good thing that's not +methoxymethane isn't it really good + + align:start position:0% +methoxymethane isn't it really good + + + align:start position:0% +methoxymethane isn't it really good +thing + + align:start position:0% +thing + + + align:start position:0% +thing +and tell them about hydrogen bonds have + + align:start position:0% +and tell them about hydrogen bonds have + + + align:start position:0% +and tell them about hydrogen bonds have +a great weekend + + align:start position:0% + + + + align:start position:0% + +you \ No newline at end of file diff --git a/PFfv1JnQB8Q.txt b/PFfv1JnQB8Q.txt new file mode 100644 index 0000000000000000000000000000000000000000..7f08e75fae2e3bc0692e73c28b3aa979056577e0 --- /dev/null +++ b/PFfv1JnQB8Q.txt @@ -0,0 +1,14898 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +to view additional materials from + + align:start position:0% +to view additional materials from + + + align:start position:0% +to view additional materials from +hundreds of MIT courses visit MIT open + + align:start position:0% +hundreds of MIT courses visit MIT open + + + align:start position:0% +hundreds of MIT courses visit MIT open +courseware at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu all right today we start a + + align:start position:0% +ocw.mit.edu all right today we start a + + + align:start position:0% +ocw.mit.edu all right today we start a +new section of NP Ness uh I think + + align:start position:0% +new section of NP Ness uh I think + + + align:start position:0% +new section of NP Ness uh I think +there'll just be one lecture about + + align:start position:0% +there'll just be one lecture about + + + align:start position:0% +there'll just be one lecture about +hamiltonicity + + align:start position:0% +hamiltonicity + + + align:start position:0% +hamiltonicity +so uh hamiltonian cycle and + + align:start position:0% +so uh hamiltonian cycle and + + + align:start position:0% +so uh hamiltonian cycle and +path we've talked about these briefly + + align:start position:0% +path we've talked about these briefly + + + align:start position:0% +path we've talked about these briefly +but uh cycle is just a uh cycle visiting + + align:start position:0% +but uh cycle is just a uh cycle visiting + + + align:start position:0% +but uh cycle is just a uh cycle visiting +every vertex exactly + + align:start position:0% + + + + align:start position:0% + +once and usually + + align:start position:0% +once and usually + + + align:start position:0% +once and usually +uh when you talk about a graph being + + align:start position:0% +uh when you talk about a graph being + + + align:start position:0% +uh when you talk about a graph being +hamiltonian you mean that there's a + + align:start position:0% +hamiltonian you mean that there's a + + + align:start position:0% +hamiltonian you mean that there's a +hamiltonian cycle also called a + + align:start position:0% +hamiltonian cycle also called a + + + align:start position:0% +hamiltonian cycle also called a +hamiltonian tour or hamiltonian circuit + + align:start position:0% +hamiltonian tour or hamiltonian circuit + + + align:start position:0% +hamiltonian tour or hamiltonian circuit +uh all mean the same thing uh and then + + align:start position:0% +uh all mean the same thing uh and then + + + align:start position:0% +uh all mean the same thing uh and then +there's hamiltonian path another problem + + align:start position:0% +there's hamiltonian path another problem + + + align:start position:0% +there's hamiltonian path another problem +we have looked at before uh and same + + align:start position:0% +we have looked at before uh and same + + + align:start position:0% +we have looked at before uh and same +thing but path that visits every vertex + + align:start position:0% +thing but path that visits every vertex + + + align:start position:0% +thing but path that visits every vertex +exactly want these are pretty much the + + align:start position:0% +exactly want these are pretty much the + + + align:start position:0% +exactly want these are pretty much the +same problem but different versions are + + align:start position:0% +same problem but different versions are + + + align:start position:0% +same problem but different versions are +useful in different settings um in case + + align:start position:0% +useful in different settings um in case + + + align:start position:0% +useful in different settings um in case +you're curious where this comes from it + + align:start position:0% +you're curious where this comes from it + + + align:start position:0% +you're curious where this comes from it +comes from this game uh introduced by + + align:start position:0% +comes from this game uh introduced by + + + align:start position:0% +comes from this game uh introduced by +Hamilton in 18 1957 he was the royal + + align:start position:0% +Hamilton in 18 1957 he was the royal + + + align:start position:0% +Hamilton in 18 1957 he was the royal +astronomer of Ireland uh back then but + + align:start position:0% +astronomer of Ireland uh back then but + + + align:start position:0% +astronomer of Ireland uh back then but +he had fun with uh games as well so here + + align:start position:0% +he had fun with uh games as well so here + + + align:start position:0% +he had fun with uh games as well so here +you have something like the graph of a + + align:start position:0% +you have something like the graph of a + + + align:start position:0% +you have something like the graph of a +doc aedin The Duel is an icosahedron + + align:start position:0% +doc aedin The Duel is an icosahedron + + + align:start position:0% +doc aedin The Duel is an icosahedron +hence the name and you want to find a + + align:start position:0% +hence the name and you want to find a + + + align:start position:0% +hence the name and you want to find a +hamiltonian circuit through it or there + + align:start position:0% +hamiltonian circuit through it or there + + + align:start position:0% +hamiltonian circuit through it or there +actually a two-player game where one + + align:start position:0% +actually a two-player game where one + + + align:start position:0% +actually a two-player game where one +person chooses a subset of the graph the + + align:start position:0% +person chooses a subset of the graph the + + + align:start position:0% +person chooses a subset of the graph the +other one tries to find hamiltonian + + align:start position:0% +other one tries to find hamiltonian + + + align:start position:0% +other one tries to find hamiltonian +circuit in that + + align:start position:0% +circuit in that + + + align:start position:0% +circuit in that +subset uh so that's where hamiltonicity + + align:start position:0% +subset uh so that's where hamiltonicity + + + align:start position:0% +subset uh so that's where hamiltonicity +comes from + + align:start position:0% +comes from + + + align:start position:0% +comes from +uh but for us today it is a nice MP + + align:start position:0% +uh but for us today it is a nice MP + + + align:start position:0% +uh but for us today it is a nice MP +complete problem we've actually seen one + + align:start position:0% +complete problem we've actually seen one + + + align:start position:0% +complete problem we've actually seen one +proof that uh planer Max degree 4 I + + align:start position:0% +proof that uh planer Max degree 4 I + + + align:start position:0% +proof that uh planer Max degree 4 I +think uh hamiltonicity is hard I think + + align:start position:0% +think uh hamiltonicity is hard I think + + + align:start position:0% +think uh hamiltonicity is hard I think +uh that was in the planer sat discussion + + align:start position:0% +uh that was in the planer sat discussion + + + align:start position:0% +uh that was in the planer sat discussion +and this is the original paper that does + + align:start position:0% +and this is the original paper that does + + + align:start position:0% +and this is the original paper that does +planer 3at and there was this proof uh I + + align:start position:0% +planer 3at and there was this proof uh I + + + align:start position:0% +planer 3at and there was this proof uh I +guess it's not actually Max degree 4 + + align:start position:0% +guess it's not actually Max degree 4 + + + align:start position:0% +guess it's not actually Max degree 4 +it's probably Max degree 6 or something + + align:start position:0% +it's probably Max degree 6 or something + + + align:start position:0% +it's probably Max degree 6 or something +uh you could get direct uh we argued the + + align:start position:0% +uh you could get direct uh we argued the + + + align:start position:0% +uh you could get direct uh we argued the +directed case this proof apparently + + align:start position:0% +directed case this proof apparently + + + align:start position:0% +directed case this proof apparently +works for the undirected case we'll get + + align:start position:0% +works for the undirected case we'll get + + + align:start position:0% +works for the undirected case we'll get +a an even stronger result here uh in + + align:start position:0% +a an even stronger result here uh in + + + align:start position:0% +a an even stronger result here uh in +general uh the problem is empty + + align:start position:0% + + + + align:start position:0% + +complete and a lot of different special + + align:start position:0% +complete and a lot of different special + + + align:start position:0% +complete and a lot of different special +cases such as the one we saw uh for + + align:start position:0% +cases such as the one we saw uh for + + + align:start position:0% +cases such as the one we saw uh for +example if you're looking for a path and + + align:start position:0% +example if you're looking for a path and + + + align:start position:0% +example if you're looking for a path and +you're giv given uh the two end + + align:start position:0% +you're giv given uh the two end + + + align:start position:0% +you're giv given uh the two end +points so normally you say is there a + + align:start position:0% +points so normally you say is there a + + + align:start position:0% +points so normally you say is there a +hamiltonian path or is there a + + align:start position:0% +hamiltonian path or is there a + + + align:start position:0% +hamiltonian path or is there a +hamiltonian cycle those are both hard in + + align:start position:0% +hamiltonian cycle those are both hard in + + + align:start position:0% +hamiltonian cycle those are both hard in +general graphs but if I give you a graph + + align:start position:0% +general graphs but if I give you a graph + + + align:start position:0% +general graphs but if I give you a graph +and I give you two nodes s& T and I want + + align:start position:0% +and I give you two nodes s& T and I want + + + align:start position:0% +and I give you two nodes s& T and I want +to know is there uh so here's the graph + + align:start position:0% +to know is there uh so here's the graph + + + align:start position:0% +to know is there uh so here's the graph +here's S and T I want to know is there a + + align:start position:0% +here's S and T I want to know is there a + + + align:start position:0% +here's S and T I want to know is there a +path that starts at s ends at t uh this + + align:start position:0% +path that starts at s ends at t uh this + + + align:start position:0% +path that starts at s ends at t uh this +is NP hard by reduction from hamiltonian + + align:start position:0% +is NP hard by reduction from hamiltonian + + + align:start position:0% +is NP hard by reduction from hamiltonian +cycle tell me what to do + + align:start position:0% +cycle tell me what to do + + + align:start position:0% +cycle tell me what to do +you add a new node which has connection + + align:start position:0% +you add a new node which has connection + + + align:start position:0% +you add a new node which has connection +to S&T and nothing else add a new node + + align:start position:0% +to S&T and nothing else add a new node + + + align:start position:0% +to S&T and nothing else add a new node +connected to S&T and nothing else yeah + + align:start position:0% +connected to S&T and nothing else yeah + + + align:start position:0% +connected to S&T and nothing else yeah +so we'll add this new node x connect to + + align:start position:0% +so we'll add this new node x connect to + + + align:start position:0% +so we'll add this new node x connect to +S&T what's interesting about adding a + + align:start position:0% +S&T what's interesting about adding a + + + align:start position:0% +S&T what's interesting about adding a +degree 2 node is you know it has I mean + + align:start position:0% +degree 2 node is you know it has I mean + + + align:start position:0% +degree 2 node is you know it has I mean +has to be in the cycle so you know that + + align:start position:0% +has to be in the cycle so you know that + + + align:start position:0% +has to be in the cycle so you know that +these two edges have to be in the + + align:start position:0% +these two edges have to be in the + + + align:start position:0% +these two edges have to be in the +cycle also if it's directed you can + + align:start position:0% +cycle also if it's directed you can + + + align:start position:0% +cycle also if it's directed you can +direct those two so it's not + + align:start position:0% +direct those two so it's not + + + align:start position:0% +direct those two so it's not +directed uh all these are going to be + + align:start position:0% +directed uh all these are going to be + + + align:start position:0% +directed uh all these are going to be +undirected + + align:start position:0% + + + + align:start position:0% + +this would preserve directedness if you + + align:start position:0% +this would preserve directedness if you + + + align:start position:0% +this would preserve directedness if you +wanted it but yeah so uh there you go so + + align:start position:0% +wanted it but yeah so uh there you go so + + + align:start position:0% +wanted it but yeah so uh there you go so +if hamiltonian Cycle's hard then + + align:start position:0% +if hamiltonian Cycle's hard then + + + align:start position:0% +if hamiltonian Cycle's hard then +hamiltonian path given to end points is + + align:start position:0% +hamiltonian path given to end points is + + + align:start position:0% +hamiltonian path given to end points is +hard easy warmup um it's also EMP + + align:start position:0% +hard easy warmup um it's also EMP + + + align:start position:0% +hard easy warmup um it's also EMP +complete for + + align:start position:0% +complete for + + + align:start position:0% +complete for +planer three + + align:start position:0% + + + + align:start position:0% + +regular three connected + + align:start position:0% + + + + align:start position:0% + +graphs where every face has degree at + + align:start position:0% +graphs where every face has degree at + + + align:start position:0% +graphs where every face has degree at +least five but bother writing that down + + align:start position:0% +least five but bother writing that down + + + align:start position:0% +least five but bother writing that down +uh it's NP hard for bipar + + align:start position:0% +uh it's NP hard for bipar + + + align:start position:0% +uh it's NP hard for bipar +graphs these are all various + + align:start position:0% +graphs these are all various + + + align:start position:0% +graphs these are all various +results uh proved in the + + align:start position:0% +results uh proved in the + + + align:start position:0% +results uh proved in the +70s uh it's going be hard for squares of + + align:start position:0% + + + + align:start position:0% + +graphs squares of graphs is interesting + + align:start position:0% +graphs squares of graphs is interesting + + + align:start position:0% +graphs squares of graphs is interesting +this is whenever you have a length two + + align:start position:0% +this is whenever you have a length two + + + align:start position:0% +this is whenever you have a length two +path you add an edge that's a square uh + + align:start position:0% +path you add an edge that's a square uh + + + align:start position:0% +path you add an edge that's a square uh +that's still + + align:start position:0% +that's still + + + align:start position:0% +that's still +hard um another fun problem is Computing + + align:start position:0% +hard um another fun problem is Computing + + + align:start position:0% +hard um another fun problem is Computing +a hamiltonian cycle given a hamiltonian + + align:start position:0% +a hamiltonian cycle given a hamiltonian + + + align:start position:0% +a hamiltonian cycle given a hamiltonian +path is also + + align:start position:0% + + + + align:start position:0% + +hard on the other hand some variations + + align:start position:0% +hard on the other hand some variations + + + align:start position:0% +hard on the other hand some variations +are easy so you have to be a little bit + + align:start position:0% +are easy so you have to be a little bit + + + align:start position:0% +are easy so you have to be a little bit +careful uh there are a lot of papers + + align:start position:0% +careful uh there are a lot of papers + + + align:start position:0% +careful uh there are a lot of papers +about various Gra s that are always + + align:start position:0% +about various Gra s that are always + + + align:start position:0% +about various Gra s that are always +hamiltonian and usually when they're + + align:start position:0% +hamiltonian and usually when they're + + + align:start position:0% +hamiltonian and usually when they're +always hamiltonian there's a good + + align:start position:0% +always hamiltonian there's a good + + + align:start position:0% +always hamiltonian there's a good +algorithm to find them here are just a + + align:start position:0% +algorithm to find them here are just a + + + align:start position:0% +algorithm to find them here are just a +couple of examples one is cubes of + + align:start position:0% +couple of examples one is cubes of + + + align:start position:0% +couple of examples one is cubes of +graphs so if you take all length three + + align:start position:0% +graphs so if you take all length three + + + align:start position:0% +graphs so if you take all length three +paths and connect them by an edge or + + align:start position:0% +paths and connect them by an edge or + + + align:start position:0% +paths and connect them by an edge or +maybe length less than or equal to three + + align:start position:0% +maybe length less than or equal to three + + + align:start position:0% +maybe length less than or equal to three +not sure exactly that's easy all such + + align:start position:0% +not sure exactly that's easy all such + + + align:start position:0% +not sure exactly that's easy all such +graphs are hamiltonian whereas squares + + align:start position:0% +graphs are hamiltonian whereas squares + + + align:start position:0% +graphs are hamiltonian whereas squares +it's still hard so that's kind of a + + align:start position:0% +it's still hard so that's kind of a + + + align:start position:0% +it's still hard so that's kind of a +limit and the other one here is planer + + align:start position:0% +limit and the other one here is planer + + + align:start position:0% +limit and the other one here is planer +three connector graphs is MP complete uh + + align:start position:0% +three connector graphs is MP complete uh + + + align:start position:0% +three connector graphs is MP complete uh +planer for connected graphs is + + align:start position:0% + + + + align:start position:0% + +polinomial this is a TTS theorem one of + + align:start position:0% +polinomial this is a TTS theorem one of + + + align:start position:0% +polinomial this is a TTS theorem one of +many TTS theorems uh all such graphs are + + align:start position:0% +many TTS theorems uh all such graphs are + + + align:start position:0% +many TTS theorems uh all such graphs are +hamiltonian so those are a few cases to + + align:start position:0% +hamiltonian so those are a few cases to + + + align:start position:0% +hamiltonian so those are a few cases to +to worry about we will see some more + + align:start position:0% +to worry about we will see some more + + + align:start position:0% +to worry about we will see some more +today and we're going to these are + + align:start position:0% +today and we're going to these are + + + align:start position:0% +today and we're going to these are +relatively simple uh we're going to + + align:start position:0% +relatively simple uh we're going to + + + align:start position:0% +relatively simple uh we're going to +prove even stricter versions of this + + align:start position:0% +prove even stricter versions of this + + + align:start position:0% +prove even stricter versions of this +problem and be complete but this starts + + align:start position:0% +problem and be complete but this starts + + + align:start position:0% +problem and be complete but this starts +to give you the flavor of what's + + align:start position:0% +to give you the flavor of what's + + + align:start position:0% +to give you the flavor of what's +there uh so in fact the first one we + + align:start position:0% +there uh so in fact the first one we + + + align:start position:0% +there uh so in fact the first one we +will + + align:start position:0% + + + + align:start position:0% + +prove + + align:start position:0% + + + + align:start position:0% + +is this may seem a little weird because + + align:start position:0% +is this may seem a little weird because + + + align:start position:0% +is this may seem a little weird because +I wanted to do undirected but we're + + align:start position:0% +I wanted to do undirected but we're + + + align:start position:0% +I wanted to do undirected but we're +going to make it undirected in a moment + + align:start position:0% +going to make it undirected in a moment + + + align:start position:0% +going to make it undirected in a moment +we're going to do a series of + + align:start position:0% +we're going to do a series of + + + align:start position:0% +we're going to do a series of +reductions first one we'll do is planer + + align:start position:0% +reductions first one we'll do is planer + + + align:start position:0% +reductions first one we'll do is planer +Max degree + + align:start position:0% +Max degree + + + align:start position:0% +Max degree +three + + align:start position:0% + + + + align:start position:0% + +graphs okay so this will be um a + + align:start position:0% +graphs okay so this will be um a + + + align:start position:0% +graphs okay so this will be um a +reduction from threat so the general + + align:start position:0% +reduction from threat so the general + + + align:start position:0% +reduction from threat so the general +idea and you please wait why you should + + align:start position:0% +idea and you please wait why you should + + + align:start position:0% +idea and you please wait why you should +care about this problem we're going to + + align:start position:0% +care about this problem we're going to + + + align:start position:0% +care about this problem we're going to +reduce it to another more interesting + + align:start position:0% +reduce it to another more interesting + + + align:start position:0% +reduce it to another more interesting +version of hamiltonicity uh but here's + + align:start position:0% +version of hamiltonicity uh but here's + + + align:start position:0% +version of hamiltonicity uh but here's +one way to represent threat has + + align:start position:0% +one way to represent threat has + + + align:start position:0% +one way to represent threat has +hamiltonicity another way similar to the + + align:start position:0% +hamiltonicity another way similar to the + + + align:start position:0% +hamiltonicity another way similar to the +one we did before uh we've got Clauses + + align:start position:0% +one we did before uh we've got Clauses + + + align:start position:0% +one we did before uh we've got Clauses +here over on the left here some of the + + align:start position:0% +here over on the left here some of the + + + align:start position:0% +here over on the left here some of the +Clauses have size two but they works for + + align:start position:0% +Clauses have size two but they works for + + + align:start position:0% +Clauses have size two but they works for +the three case uh here we have the + + align:start position:0% +the three case uh here we have the + + + align:start position:0% +the three case uh here we have the +variables and the the key uh concept + + align:start position:0% +variables and the the key uh concept + + + align:start position:0% +variables and the the key uh concept +here is this notation this is notation + + align:start position:0% +here is this notation this is notation + + + align:start position:0% +here is this notation this is notation +shorthand for a more complicated Gadget + + align:start position:0% +shorthand for a more complicated Gadget + + + align:start position:0% +shorthand for a more complicated Gadget +um which is to say that these two things + + align:start position:0% +um which is to say that these two things + + + align:start position:0% +um which is to say that these two things +should not be both chosen this is an + + align:start position:0% +should not be both chosen this is an + + + align:start position:0% +should not be both chosen this is an +exclusive or uh in fact exactly one of + + align:start position:0% +exclusive or uh in fact exactly one of + + + align:start position:0% +exclusive or uh in fact exactly one of +them should be chosen so that forces X1 + + align:start position:0% +them should be chosen so that forces X1 + + + align:start position:0% +them should be chosen so that forces X1 +to be the opposite of + + align:start position:0% +to be the opposite of + + + align:start position:0% +to be the opposite of +X1 bar and it also lets you duplicate + + align:start position:0% +X1 bar and it also lets you duplicate + + + align:start position:0% +X1 bar and it also lets you duplicate +things so here we get multiple copies of + + align:start position:0% +things so here we get multiple copies of + + + align:start position:0% +things so here we get multiple copies of +the variable you keep doing that several + + align:start position:0% +the variable you keep doing that several + + + align:start position:0% +the variable you keep doing that several +times you get many copies of variable + + align:start position:0% +times you get many copies of variable + + + align:start position:0% +times you get many copies of variable +and its complement and then we're also + + align:start position:0% +and its complement and then we're also + + + align:start position:0% +and its complement and then we're also +going to use some connections like this + + align:start position:0% +going to use some connections like this + + + align:start position:0% +going to use some connections like this +we're going to need a crossover Gadget + + align:start position:0% +we're going to need a crossover Gadget + + + align:start position:0% +we're going to need a crossover Gadget +uh but this will say that uh you well so + + align:start position:0% +uh but this will say that uh you well so + + + align:start position:0% +uh but this will say that uh you well so +this is going to be some clause which uh + + align:start position:0% +this is going to be some clause which uh + + + align:start position:0% +this is going to be some clause which uh +it's not literally as drawn again this + + align:start position:0% +it's not literally as drawn again this + + + align:start position:0% +it's not literally as drawn again this +is notation for a gadget that force is + + align:start position:0% +is notation for a gadget that force is + + + align:start position:0% +is notation for a gadget that force is +going to force at least one of these to + + align:start position:0% +going to force at least one of these to + + + align:start position:0% +going to force at least one of these to +be uh traversable + + align:start position:0% +be uh traversable + + + align:start position:0% +be uh traversable +okay so that overall should represent + + align:start position:0% +okay so that overall should represent + + + align:start position:0% +okay so that overall should represent +thre set we need a clause Gadget we need + + align:start position:0% +thre set we need a clause Gadget we need + + + align:start position:0% +thre set we need a clause Gadget we need +this exclusive or so that we can split + + align:start position:0% +this exclusive or so that we can split + + + align:start position:0% +this exclusive or so that we can split +duplicate things overall the cycle is + + align:start position:0% +duplicate things overall the cycle is + + + align:start position:0% +duplicate things overall the cycle is +going to do this so it's going to visit + + align:start position:0% +going to do this so it's going to visit + + + align:start position:0% +going to do this so it's going to visit +all the variables in order then all the + + align:start position:0% +all the variables in order then all the + + + align:start position:0% +all the variables in order then all the +Clauses in order uh so we don't we can't + + align:start position:0% +Clauses in order uh so we don't we can't + + + align:start position:0% +Clauses in order uh so we don't we can't +get anything interesting out of + + align:start position:0% +get anything interesting out of + + + align:start position:0% +get anything interesting out of +planarity because that graphs with these + + align:start position:0% +planarity because that graphs with these + + + align:start position:0% +planarity because that graphs with these +connections is not going to be planer so + + align:start position:0% +connections is not going to be planer so + + + align:start position:0% +connections is not going to be planer so +we'll need a crossover and those are the + + align:start position:0% +we'll need a crossover and those are the + + + align:start position:0% +we'll need a crossover and those are the +three gadgets we need yeah why we use + + align:start position:0% +three gadgets we need yeah why we use + + + align:start position:0% +three gadgets we need yeah why we use +the exclusive to connect + + align:start position:0% +the exclusive to connect + + + align:start position:0% +the exclusive to connect +variables uh so the idea is here there's + + align:start position:0% +variables uh so the idea is here there's + + + align:start position:0% +variables uh so the idea is here there's +a choice do I choose this Edge or this + + align:start position:0% +a choice do I choose this Edge or this + + + align:start position:0% +a choice do I choose this Edge or this +Edge in the hamiltonian cycle and I want + + align:start position:0% +Edge in the hamiltonian cycle and I want + + + align:start position:0% +Edge in the hamiltonian cycle and I want +the choice for this copy of X1 to be the + + align:start position:0% +the choice for this copy of X1 to be the + + + align:start position:0% +the choice for this copy of X1 to be the +same as for that copy of X1 so the + + align:start position:0% +same as for that copy of X1 so the + + + align:start position:0% +same as for that copy of X1 so the +exclusive or forces each instance of X1 + + align:start position:0% +exclusive or forces each instance of X1 + + + align:start position:0% +exclusive or forces each instance of X1 +to be the same in general if there's K + + align:start position:0% +to be the same in general if there's K + + + align:start position:0% +to be the same in general if there's K +instances you'd have K of these connect + + align:start position:0% +instances you'd have K of these connect + + + align:start position:0% +instances you'd have K of these connect +that use the same Gadget to connect it + + align:start position:0% +that use the same Gadget to connect it + + + align:start position:0% +that use the same Gadget to connect it +to the instance inside the Clause + + align:start position:0% +to the instance inside the Clause + + + align:start position:0% +to the instance inside the Clause +uh I guess the the the issue the reason + + align:start position:0% +uh I guess the the the issue the reason + + + align:start position:0% +uh I guess the the the issue the reason +why we need two copies here is that you + + align:start position:0% +why we need two copies here is that you + + + align:start position:0% +why we need two copies here is that you +can't we'll see you can't have two XR + + align:start position:0% +can't we'll see you can't have two XR + + + align:start position:0% +can't we'll see you can't have two XR +gadgets going to the same place so it + + align:start position:0% +gadgets going to the same place so it + + + align:start position:0% +gadgets going to the same place so it +will be clear once we've seen the XR + + align:start position:0% +will be clear once we've seen the XR + + + align:start position:0% +will be clear once we've seen the XR +Gadget we want two distinct copies so + + align:start position:0% +Gadget we want two distinct copies so + + + align:start position:0% +Gadget we want two distinct copies so +that these two things can point to + + align:start position:0% +that these two things can point to + + + align:start position:0% +that these two things can point to +different copies of X1 that's why we're + + align:start position:0% +different copies of X1 that's why we're + + + align:start position:0% +different copies of X1 that's why we're +making a copy like that does that make + + align:start position:0% +making a copy like that does that make + + + align:start position:0% +making a copy like that does that make +sense okay next + + align:start position:0% +sense okay next + + + align:start position:0% +sense okay next +slide uh actually same slide I should + + align:start position:0% +slide uh actually same slide I should + + + align:start position:0% +slide uh actually same slide I should +just show them uh so here is maybe let's + + align:start position:0% +just show them uh so here is maybe let's + + + align:start position:0% +just show them uh so here is maybe let's +start with the XR Gadget because the + + align:start position:0% +start with the XR Gadget because the + + + align:start position:0% +start with the XR Gadget because the +Clause Clause doesn't actually use it + + align:start position:0% +Clause Clause doesn't actually use it + + + align:start position:0% +Clause Clause doesn't actually use it +but uh so the our Gadget is if we have + + align:start position:0% +but uh so the our Gadget is if we have + + + align:start position:0% +but uh so the our Gadget is if we have +two edges of opposite direction relative + + align:start position:0% +two edges of opposite direction relative + + + align:start position:0% +two edges of opposite direction relative +to the way we're being connected uh I + + align:start position:0% +to the way we're being connected uh I + + + align:start position:0% +to the way we're being connected uh I +think it also works in the other way + + align:start position:0% +think it also works in the other way + + + align:start position:0% +think it also works in the other way +because these are now these are also + + align:start position:0% +because these are now these are also + + + align:start position:0% +because these are now these are also +opposite if you redraw it this way uh + + align:start position:0% +opposite if you redraw it this way uh + + + align:start position:0% +opposite if you redraw it this way uh +we're just going to have this picture uh + + align:start position:0% +we're just going to have this picture uh + + + align:start position:0% +we're just going to have this picture uh +which can be traversed either this guy + + align:start position:0% +which can be traversed either this guy + + + align:start position:0% +which can be traversed either this guy +can come in here we're really using + + align:start position:0% +can come in here we're really using + + + align:start position:0% +can come in here we're really using +direction directionality of the graph + + align:start position:0% +direction directionality of the graph + + + align:start position:0% +direction directionality of the graph +you can Traverse the top Edge or you can + + align:start position:0% +you can Traverse the top Edge or you can + + + align:start position:0% +you can Traverse the top Edge or you can +Traverse the bottom Edge and the the + + align:start position:0% +Traverse the bottom Edge and the the + + + align:start position:0% +Traverse the bottom Edge and the the +opposite direction um but you can't you + + align:start position:0% +opposite direction um but you can't you + + + align:start position:0% +opposite direction um but you can't you +can't just turn around because then + + align:start position:0% +can't just turn around because then + + + align:start position:0% +can't just turn around because then +these vertices would be uncovered uh and + + align:start position:0% +these vertices would be uncovered uh and + + + align:start position:0% +these vertices would be uncovered uh and +if as soon as you've gone this far uh + + align:start position:0% +if as soon as you've gone this far uh + + + align:start position:0% +if as soon as you've gone this far uh +you can't come back this way so once you + + align:start position:0% +you can't come back this way so once you + + + align:start position:0% +you can't come back this way so once you +enter here you're forced to leave there + + align:start position:0% +enter here you're forced to leave there + + + align:start position:0% +enter here you're forced to leave there +once you enter here you're forced to + + align:start position:0% +once you enter here you're forced to + + + align:start position:0% +once you enter here you're forced to +leave there if you want to cover + + align:start position:0% +leave there if you want to cover + + + align:start position:0% +leave there if you want to cover +everything so that's an exclusive or and + + align:start position:0% +everything so that's an exclusive or and + + + align:start position:0% +everything so that's an exclusive or and +at least one of those better + + align:start position:0% +at least one of those better + + + align:start position:0% +at least one of those better +happen so that is what happens over + + align:start position:0% +happen so that is what happens over + + + align:start position:0% +happen so that is what happens over +there and also what we'll end up being + + align:start position:0% +there and also what we'll end up being + + + align:start position:0% +there and also what we'll end up being +doing here except we also need the + + align:start position:0% +doing here except we also need the + + + align:start position:0% +doing here except we also need the +crossing case on the other hand for the + + align:start position:0% +crossing case on the other hand for the + + + align:start position:0% +crossing case on the other hand for the +claw + + align:start position:0% +claw + + + align:start position:0% +claw +the idea + + align:start position:0% +the idea + + + align:start position:0% +the idea +is uh basically there's a cycle over + + align:start position:0% +is uh basically there's a cycle over + + + align:start position:0% +is uh basically there's a cycle over +here which is fine but somehow that + + align:start position:0% +here which is fine but somehow that + + + align:start position:0% +here which is fine but somehow that +cycle for that Clause uh has to be + + align:start position:0% +cycle for that Clause uh has to be + + + align:start position:0% +cycle for that Clause uh has to be +connected into the big cycle that we've + + align:start position:0% +connected into the big cycle that we've + + + align:start position:0% +connected into the big cycle that we've +drawn already and at least one of the + + align:start position:0% +drawn already and at least one of the + + + align:start position:0% +drawn already and at least one of the +variables needs to connect to that so um + + align:start position:0% +variables needs to connect to that so um + + + align:start position:0% +variables needs to connect to that so um +the idea is we can uh come up here uh so + + align:start position:0% +the idea is we can uh come up here uh so + + + align:start position:0% +the idea is we can uh come up here uh so +also these vertices need to be + + align:start position:0% +also these vertices need to be + + + align:start position:0% +also these vertices need to be +covered uh so we can come up here go + + align:start position:0% +covered uh so we can come up here go + + + align:start position:0% +covered uh so we can come up here go +over here loop + + align:start position:0% +over here loop + + + align:start position:0% +over here loop +around uh and be happy and then we've + + align:start position:0% +around uh and be happy and then we've + + + align:start position:0% +around uh and be happy and then we've +we've grabbed the entire + + align:start position:0% +we've grabbed the entire + + + align:start position:0% +we've grabbed the entire +cycle um also when we've grabbed this + + align:start position:0% +cycle um also when we've grabbed this + + + align:start position:0% +cycle um also when we've grabbed this +cycle we can + + align:start position:0% + + + + align:start position:0% + +also we can also grab these + + align:start position:0% +also we can also grab these + + + align:start position:0% +also we can also grab these +vertices right all of + + align:start position:0% +vertices right all of + + + align:start position:0% +vertices right all of +them that's only going to be possible if + + align:start position:0% +them that's only going to be possible if + + + align:start position:0% +them that's only going to be possible if +this is + + align:start position:0% +this is + + + align:start position:0% +this is +possible so uh in the outer side + + align:start position:0% +possible so uh in the outer side + + + align:start position:0% +possible so uh in the outer side +uh we we can't go here and then up here + + align:start position:0% +uh we we can't go here and then up here + + + align:start position:0% +uh we we can't go here and then up here +we can go here over here that's also + + align:start position:0% +we can go here over here that's also + + + align:start position:0% +we can go here over here that's also +fine okay uh good I see so the the issue + + align:start position:0% +fine okay uh good I see so the the issue + + + align:start position:0% +fine okay uh good I see so the the issue +is so these are actually flexible these + + align:start position:0% +is so these are actually flexible these + + + align:start position:0% +is so these are actually flexible these +guys can be covered basically from the + + align:start position:0% +guys can be covered basically from the + + + align:start position:0% +guys can be covered basically from the +right side or from the left side either + + align:start position:0% +right side or from the left side either + + + align:start position:0% +right side or from the left side either +way so it doesn't matter whether you + + align:start position:0% +way so it doesn't matter whether you + + + align:start position:0% +way so it doesn't matter whether you +take this path or this + + align:start position:0% +take this path or this + + + align:start position:0% +take this path or this +path but uh at least one of them has at + + align:start position:0% +path but uh at least one of them has at + + + align:start position:0% +path but uh at least one of them has at +least one of these uh sort of pairs of + + align:start position:0% +least one of these uh sort of pairs of + + + align:start position:0% +least one of these uh sort of pairs of +edges as they're drawn over here you + + align:start position:0% +edges as they're drawn over here you + + + align:start position:0% +edges as they're drawn over here you +need to be able to choose the left + + align:start position:0% +need to be able to choose the left + + + align:start position:0% +need to be able to choose the left +choice and therefore get the big + + align:start position:0% +choice and therefore get the big + + + align:start position:0% +choice and therefore get the big +cycle and the the issue with that is + + align:start position:0% +cycle and the the issue with that is + + + align:start position:0% +cycle and the the issue with that is +because you have this X or it's an + + align:start position:0% +because you have this X or it's an + + + align:start position:0% +because you have this X or it's an +exclusive or Le exactly one of those two + + align:start position:0% +exclusive or Le exactly one of those two + + + align:start position:0% +exclusive or Le exactly one of those two +things must be true so in some cases + + align:start position:0% +things must be true so in some cases + + + align:start position:0% +things must be true so in some cases +you'll be forced to choose the right + + align:start position:0% +you'll be forced to choose the right + + + align:start position:0% +you'll be forced to choose the right +thing if this one if this variable chose + + align:start position:0% +thing if this one if this variable chose + + + align:start position:0% +thing if this one if this variable chose +the right path then this one will also + + align:start position:0% +the right path then this one will also + + + align:start position:0% +the right path then this one will also +have to choose the right path because of + + align:start position:0% +have to choose the right path because of + + + align:start position:0% +have to choose the right path because of +this exclusive ore uh and preventing you + + align:start position:0% +this exclusive ore uh and preventing you + + + align:start position:0% +this exclusive ore uh and preventing you +from grabbing the cycle you're fine in + + align:start position:0% +from grabbing the cycle you're fine in + + + align:start position:0% +from grabbing the cycle you're fine in +this Clause if at least one of them you + + align:start position:0% +this Clause if at least one of them you + + + align:start position:0% +this Clause if at least one of them you +choose the left path uh in fact this if + + align:start position:0% +choose the left path uh in fact this if + + + align:start position:0% +choose the left path uh in fact this if +you look very closely there are some + + align:start position:0% +you look very closely there are some + + + align:start position:0% +you look very closely there are some +bold edges indicating which ones got + + align:start position:0% +bold edges indicating which ones got + + + align:start position:0% +bold edges indicating which ones got +chosen here so here three of them were + + align:start position:0% +chosen here so here three of them were + + + align:start position:0% +chosen here so here three of them were +on two of them were on the right one of + + align:start position:0% +on two of them were on the right one of + + + align:start position:0% +on two of them were on the right one of +them was on the left for this clause in + + align:start position:0% +them was on the left for this clause in + + + align:start position:0% +them was on the left for this clause in +general at Le if at least one of them's + + align:start position:0% +general at Le if at least one of them's + + + align:start position:0% +general at Le if at least one of them's +on the left you're okay for the + + align:start position:0% +on the left you're okay for the + + + align:start position:0% +on the left you're okay for the +Clause clear at a high level now this + + align:start position:0% +Clause clear at a high level now this + + + align:start position:0% +Clause clear at a high level now this +would work fine if we didn't care about + + align:start position:0% +would work fine if we didn't care about + + + align:start position:0% +would work fine if we didn't care about +planarity uh but I want planer directed + + align:start position:0% +planarity uh but I want planer directed + + + align:start position:0% +planarity uh but I want planer directed +Max degree 3 at this point we should be + + align:start position:0% +Max degree 3 at this point we should be + + + align:start position:0% +Max degree 3 at this point we should be +directed Max degree 3 so the the that's + + align:start position:0% +directed Max degree 3 so the the that's + + + align:start position:0% +directed Max degree 3 so the the that's +an improvement from last last time terms + + align:start position:0% +an improvement from last last time terms + + + align:start position:0% +an improvement from last last time terms +of + + align:start position:0% +of + + + align:start position:0% +of +degrees uh and then there's this fun + + align:start position:0% +degrees uh and then there's this fun + + + align:start position:0% +degrees uh and then there's this fun +figure for the crossover so in general + + align:start position:0% +figure for the crossover so in general + + + align:start position:0% +figure for the crossover so in general +that's just a repetition of what our + + align:start position:0% +that's just a repetition of what our + + + align:start position:0% +that's just a repetition of what our +exor Gadget was now we have Crossing + + align:start position:0% +exor Gadget was now we have Crossing + + + align:start position:0% +exor Gadget was now we have Crossing +xover we have Crossing xor constraints + + align:start position:0% +xover we have Crossing xor constraints + + + align:start position:0% +xover we have Crossing xor constraints +so here's a typical example let's say we + + align:start position:0% +so here's a typical example let's say we + + + align:start position:0% +so here's a typical example let's say we +have this exor trying to go from there + + align:start position:0% +have this exor trying to go from there + + + align:start position:0% +have this exor trying to go from there +to there and it crosses these other + + align:start position:0% +to there and it crosses these other + + + align:start position:0% +to there and it crosses these other +exors uh so what we're going to do is + + align:start position:0% +exors uh so what we're going to do is + + + align:start position:0% +exors uh so what we're going to do is +build something like that gadget for the + + align:start position:0% +build something like that gadget for the + + + align:start position:0% +build something like that gadget for the +for the vertical connection with this + + align:start position:0% +for the vertical connection with this + + + align:start position:0% +for the vertical connection with this +and this and this and this and we + + align:start position:0% +and this and this and this and we + + + align:start position:0% +and this and this and this and we +duplicate these edges that doesn't help + + align:start position:0% +duplicate these edges that doesn't help + + + align:start position:0% +duplicate these edges that doesn't help +you from I mean it's the same as that + + align:start position:0% +you from I mean it's the same as that + + + align:start position:0% +you from I mean it's the same as that +picture just happen to duplicate them + + align:start position:0% +picture just happen to duplicate them + + + align:start position:0% +picture just happen to duplicate them +the reason we do that is we're going to + + align:start position:0% +the reason we do that is we're going to + + + align:start position:0% +the reason we do that is we're going to +put xor across like this and this forces + + align:start position:0% +put xor across like this and this forces + + + align:start position:0% +put xor across like this and this forces +um an alternation right so if this is in + + align:start position:0% +um an alternation right so if this is in + + + align:start position:0% +um an alternation right so if this is in +then this must be out so this must be in + + align:start position:0% +then this must be out so this must be in + + + align:start position:0% +then this must be out so this must be in +so this must be out so this must be in + + align:start position:0% +so this must be out so this must be in + + + align:start position:0% +so this must be out so this must be in +and so on all the way through and so + + align:start position:0% +and so on all the way through and so + + + align:start position:0% +and so on all the way through and so +that forces an exor between this Edge + + align:start position:0% +that forces an exor between this Edge + + + align:start position:0% +that forces an exor between this Edge +and that + + align:start position:0% +and that + + + align:start position:0% +and that +edge + + align:start position:0% +edge + + + align:start position:0% +edge +cool so that is the crossing X over X or + + align:start position:0% +cool so that is the crossing X over X or + + + align:start position:0% +cool so that is the crossing X over X or +Gadget which you plug into all of these + + align:start position:0% +Gadget which you plug into all of these + + + align:start position:0% +Gadget which you plug into all of these +pictures and you end up with planer + + align:start position:0% +pictures and you end up with planer + + + align:start position:0% +pictures and you end up with planer +directed Max degree 3 all right so far + + align:start position:0% +directed Max degree 3 all right so far + + + align:start position:0% +directed Max degree 3 all right so far +so + + align:start position:0% +so + + + align:start position:0% +so +good + + align:start position:0% +good + + + align:start position:0% +good +next I have a goal I'm still not going + + align:start position:0% +next I have a goal I'm still not going + + + align:start position:0% +next I have a goal I'm still not going +to tell you the goal uh where + + align:start position:0% +to tell you the goal uh where + + + align:start position:0% +to tell you the goal uh where +uh next one is going to be planer + + align:start position:0% + + + + align:start position:0% + +bipartite uh Max degree + + align:start position:0% + + + + align:start position:0% + + + align:start position:0% + + + + align:start position:0% + +graphs uh + + align:start position:0% + + + + align:start position:0% + +undirected this is going to be one of + + align:start position:0% +undirected this is going to be one of + + + align:start position:0% +undirected this is going to be one of +our simplest reductions ever there it is + + align:start position:0% +our simplest reductions ever there it is + + + align:start position:0% +our simplest reductions ever there it is +uh so the cool thing about ma degree 3 + + align:start position:0% +uh so the cool thing about ma degree 3 + + + align:start position:0% +uh so the cool thing about ma degree 3 +directed uh I mean there are few cases + + align:start position:0% +directed uh I mean there are few cases + + + align:start position:0% +directed uh I mean there are few cases +you can exclude you can't have three + + align:start position:0% +you can exclude you can't have three + + + align:start position:0% +you can exclude you can't have three +incoming edges you can't have three + + align:start position:0% +incoming edges you can't have three + + + align:start position:0% +incoming edges you can't have three +outgoing edges be pretty hard to have a + + align:start position:0% +outgoing edges be pretty hard to have a + + + align:start position:0% +outgoing edges be pretty hard to have a +cycle that includes such vertices uh so + + align:start position:0% +cycle that includes such vertices uh so + + + align:start position:0% +cycle that includes such vertices uh so +you could have degree 2 vertices but um + + align:start position:0% +you could have degree 2 vertices but um + + + align:start position:0% +you could have degree 2 vertices but um +I don't think we even had any uh did I + + align:start position:0% +I don't think we even had any uh did I + + + align:start position:0% +I don't think we even had any uh did I +say do we have degree 3 uh degree 2 in + + align:start position:0% +say do we have degree 3 uh degree 2 in + + + align:start position:0% +say do we have degree 3 uh degree 2 in +this + + align:start position:0% +this + + + align:start position:0% +this +picture probably not I mean if we did we + + align:start position:0% +picture probably not I mean if we did we + + + align:start position:0% +picture probably not I mean if we did we +could double The Edge or something so + + align:start position:0% +could double The Edge or something so + + + align:start position:0% +could double The Edge or something so +that was probably actually planer + + align:start position:0% +that was probably actually planer + + + align:start position:0% +that was probably actually planer +directed three regular okay but now + + align:start position:0% +directed three regular okay but now + + + align:start position:0% +directed three regular okay but now +undirected but you can basically have + + align:start position:0% +undirected but you can basically have + + + align:start position:0% +undirected but you can basically have +two edges in one out or one Edge in and + + align:start position:0% +two edges in one out or one Edge in and + + + align:start position:0% +two edges in one out or one Edge in and +two + + align:start position:0% +two + + + align:start position:0% +two +out uh and we're going to repr we're + + align:start position:0% +out uh and we're going to repr we're + + + align:start position:0% +out uh and we're going to repr we're +going to convert that so the interesting + + align:start position:0% +going to convert that so the interesting + + + align:start position:0% +going to convert that so the interesting +thing here you have to visit this vertex + + align:start position:0% +thing here you have to visit this vertex + + + align:start position:0% +thing here you have to visit this vertex +which means you have to visit this + + align:start position:0% +which means you have to visit this + + + align:start position:0% +which means you have to visit this +Edge right in any hamiltonian cycle + + align:start position:0% +Edge right in any hamiltonian cycle + + + align:start position:0% +Edge right in any hamiltonian cycle +because once you come here you've got to + + align:start position:0% +because once you come here you've got to + + + align:start position:0% +because once you come here you've got to +leave on that edge similarly you have to + + align:start position:0% +leave on that edge similarly you have to + + + align:start position:0% +leave on that edge similarly you have to +visit this Edge you can tell that just + + align:start position:0% +visit this Edge you can tell that just + + + align:start position:0% +visit this Edge you can tell that just +from this picture so we call these + + align:start position:0% +from this picture so we call these + + + align:start position:0% +from this picture so we call these +forced edges + + align:start position:0% +forced edges + + + align:start position:0% +forced edges +and we can kind of represent that by + + align:start position:0% +and we can kind of represent that by + + + align:start position:0% +and we can kind of represent that by +adding a Vertex there says hey you've + + align:start position:0% +adding a Vertex there says hey you've + + + align:start position:0% +adding a Vertex there says hey you've +got to visit that edge so you're going + + align:start position:0% +got to visit that edge so you're going + + + align:start position:0% +got to visit that edge so you're going +to visit it by that little path there + + align:start position:0% +to visit it by that little path there + + + align:start position:0% +to visit it by that little path there +okay and now things are + + align:start position:0% +okay and now things are + + + align:start position:0% +okay and now things are +bipartite uh and the bipar tiess is + + align:start position:0% +bipartite uh and the bipar tiess is + + + align:start position:0% +bipartite uh and the bipar tiess is +essentially forcing the directionality + + align:start position:0% +essentially forcing the directionality + + + align:start position:0% +essentially forcing the directionality +as well so let's say when you come into + + align:start position:0% +as well so let's say when you come into + + + align:start position:0% +as well so let's say when you come into +a vertex and you're blue uh so that + + align:start position:0% +a vertex and you're blue uh so that + + + align:start position:0% +a vertex and you're blue uh so that +means these guys have had to have been + + align:start position:0% +means these guys have had to have been + + + align:start position:0% +means these guys have had to have been +red uh you're leaving whenever you leave + + align:start position:0% +red uh you're leaving whenever you leave + + + align:start position:0% +red uh you're leaving whenever you leave +you first visit a red vertex and then go + + align:start position:0% +you first visit a red vertex and then go + + + align:start position:0% +you first visit a red vertex and then go +so here you're coming in again as blue + + align:start position:0% +so here you're coming in again as blue + + + align:start position:0% +so here you're coming in again as blue +and then uh before you leave you turn + + align:start position:0% +and then uh before you leave you turn + + + align:start position:0% +and then uh before you leave you turn +red and so you will alternate always + + align:start position:0% +red and so you will alternate always + + + align:start position:0% +red and so you will alternate always +because you've satisfied directionality + + align:start position:0% +because you've satisfied directionality + + + align:start position:0% +because you've satisfied directionality +over here I mean the the outgoing edge + + align:start position:0% +over here I mean the the outgoing edge + + + align:start position:0% +over here I mean the the outgoing edge +here becomes an incoming Edge to the + + align:start position:0% +here becomes an incoming Edge to the + + + align:start position:0% +here becomes an incoming Edge to the +next vertex that means you'll be going + + align:start position:0% +next vertex that means you'll be going + + + align:start position:0% +next vertex that means you'll be going +into a blue vertex either because it's + + align:start position:0% +into a blue vertex either because it's + + + align:start position:0% +into a blue vertex either because it's +like this or like + + align:start position:0% +like this or like + + + align:start position:0% +like this or like +that okay and you + + align:start position:0% +that okay and you + + + align:start position:0% +that okay and you +are uh effectively forcing + + align:start position:0% +are uh effectively forcing + + + align:start position:0% +are uh effectively forcing +directionality um + + align:start position:0% +directionality um + + + align:start position:0% +directionality um +um I mean everything could be + + align:start position:0% +um I mean everything could be + + + align:start position:0% +um I mean everything could be +reversed but + + align:start position:0% +reversed but + + + align:start position:0% +reversed but +uh yeah because you're always coming + + align:start position:0% +uh yeah because you're always coming + + + align:start position:0% +uh yeah because you're always coming +into a blue vertex and leaving on a red + + align:start position:0% +into a blue vertex and leaving on a red + + + align:start position:0% +into a blue vertex and leaving on a red +that forces you to be going from the the + + align:start position:0% +that forces you to be going from the the + + + align:start position:0% +that forces you to be going from the the +tail of a of an arrow to the head of an + + align:start position:0% +tail of a of an arrow to the head of an + + + align:start position:0% +tail of a of an arrow to the head of an +of an arrow so same thing by symmetry + + align:start position:0% +of an arrow so same thing by symmetry + + + align:start position:0% +of an arrow so same thing by symmetry +okay so these problems are actually + + align:start position:0% +okay so these problems are actually + + + align:start position:0% +okay so these problems are actually +really close to each other and it's sort + + align:start position:0% +really close to each other and it's sort + + + align:start position:0% +really close to each other and it's sort +of uh these were done in different + + align:start position:0% +of uh these were done in different + + + align:start position:0% +of uh these were done in different +papers but uh this was an older one and + + align:start position:0% +papers but uh this was an older one and + + + align:start position:0% +papers but uh this was an older one and +then this problem was introduced for + + align:start position:0% +then this problem was introduced for + + + align:start position:0% +then this problem was introduced for +another + + align:start position:0% +another + + + align:start position:0% +another +reason which is grid + + align:start position:0% +reason which is grid + + + align:start position:0% +reason which is grid +graphs this is where I really want to + + align:start position:0% + + + + align:start position:0% + +go so the idea with the grid graph is uh + + align:start position:0% +go so the idea with the grid graph is uh + + + align:start position:0% +go so the idea with the grid graph is uh +you let's say have a set of + + align:start position:0% + + + + align:start position:0% + +points on the Square lattice + + align:start position:0% + + + + align:start position:0% + +and then you're going to have an edge + + align:start position:0% +and then you're going to have an edge + + + align:start position:0% +and then you're going to have an edge +whenever you have two points at unit + + align:start position:0% + + + + align:start position:0% + +distance so let me draw an + + align:start position:0% +distance so let me draw an + + + align:start position:0% +distance so let me draw an +example cheat and have some examples + + align:start position:0% +example cheat and have some examples + + + align:start position:0% +example cheat and have some examples +drawn for me uh this is in a much more + + align:start position:0% +drawn for me uh this is in a much more + + + align:start position:0% +drawn for me uh this is in a much more +recent paper but it's some nice pictures + + align:start position:0% +recent paper but it's some nice pictures + + + align:start position:0% +recent paper but it's some nice pictures +so uh we're just choosing a set of + + align:start position:0% +so uh we're just choosing a set of + + + align:start position:0% +so uh we're just choosing a set of +points in the sare grid and then + + align:start position:0% +points in the sare grid and then + + + align:start position:0% +points in the sare grid and then +whenever we have two points that are + + align:start position:0% +whenever we have two points that are + + + align:start position:0% +whenever we have two points that are +unit distance apart you're forced to + + align:start position:0% +unit distance apart you're forced to + + + align:start position:0% +unit distance apart you're forced to +have an edge there you can't say there's + + align:start position:0% +have an edge there you can't say there's + + + align:start position:0% +have an edge there you can't say there's +no Edge that would be a subgraph of a + + align:start position:0% +no Edge that would be a subgraph of a + + + align:start position:0% +no Edge that would be a subgraph of a +grid graph uh but for example when this + + align:start position:0% +grid graph uh but for example when this + + + align:start position:0% +grid graph uh but for example when this +point is absent you don't get any + + align:start position:0% +point is absent you don't get any + + + align:start position:0% +point is absent you don't get any +connections through + + align:start position:0% +connections through + + + align:start position:0% +connections through +here uh so these are all examples of + + align:start position:0% +here uh so these are all examples of + + + align:start position:0% +here uh so these are all examples of +grid + + align:start position:0% +grid + + + align:start position:0% +grid +graphs okay um now there's one special + + align:start position:0% +graphs okay um now there's one special + + + align:start position:0% +graphs okay um now there's one special +case or in general we we distinguish U + + align:start position:0% +case or in general we we distinguish U + + + align:start position:0% +case or in general we we distinguish U +there's sort of three types of Faces in + + align:start position:0% +there's sort of three types of Faces in + + + align:start position:0% +there's sort of three types of Faces in +such a planer graph there's what you + + align:start position:0% +such a planer graph there's what you + + + align:start position:0% +such a planer graph there's what you +might call pixels little one by one + + align:start position:0% +might call pixels little one by one + + + align:start position:0% +might call pixels little one by one +squares there's uh the outside face and + + align:start position:0% +squares there's uh the outside face and + + + align:start position:0% +squares there's uh the outside face and +then there's everything else which we + + align:start position:0% +then there's everything else which we + + + align:start position:0% +then there's everything else which we +call holes so any non length four um + + align:start position:0% +call holes so any non length four um + + + align:start position:0% +call holes so any non length four um +face we call a hole if there are no + + align:start position:0% +face we call a hole if there are no + + + align:start position:0% +face we call a hole if there are no +holes we call it a solid grid + + align:start position:0% +holes we call it a solid grid + + + align:start position:0% +holes we call it a solid grid +graph um this is interesting + + align:start position:0% +graph um this is interesting + + + align:start position:0% +graph um this is interesting +because solid grid graphs you can solve + + align:start position:0% +because solid grid graphs you can solve + + + align:start position:0% +because solid grid graphs you can solve +hamiltonicity and polinomial time it's + + align:start position:0% +hamiltonicity and polinomial time it's + + + align:start position:0% +hamiltonicity and polinomial time it's +not always possible but there is a + + align:start position:0% +not always possible but there is a + + + align:start position:0% +not always possible but there is a +polinomial time algorithm for solving + + align:start position:0% +polinomial time algorithm for solving + + + align:start position:0% +polinomial time algorithm for solving +the solid grid graph Case by umans and + + align:start position:0% +the solid grid graph Case by umans and + + + align:start position:0% +the solid grid graph Case by umans and +lenhard 97 it's very complicated + + align:start position:0% +lenhard 97 it's very complicated + + + align:start position:0% +lenhard 97 it's very complicated +algorithm luckily this is a hardness + + align:start position:0% +algorithm luckily this is a hardness + + + align:start position:0% +algorithm luckily this is a hardness +proof class so I don't have to cover it + + align:start position:0% +proof class so I don't have to cover it + + + align:start position:0% +proof class so I don't have to cover it +um I'm going to focus on the hardness + + align:start position:0% +um I'm going to focus on the hardness + + + align:start position:0% +um I'm going to focus on the hardness +when you allow + + align:start position:0% + + + + align:start position:0% + +holes okay + + align:start position:0% +holes okay + + + align:start position:0% +holes okay +so this is where things get fun we are + + align:start position:0% +so this is where things get fun we are + + + align:start position:0% +so this is where things get fun we are +going to + + align:start position:0% +going to + + + align:start position:0% +going to +reduce so we did a reduction from here + + align:start position:0% +reduce so we did a reduction from here + + + align:start position:0% +reduce so we did a reduction from here +to here we're going to do reduction from + + align:start position:0% +to here we're going to do reduction from + + + align:start position:0% +to here we're going to do reduction from +here to here so we're going to suppose + + align:start position:0% +here to here so we're going to suppose + + + align:start position:0% +here to here so we're going to suppose +that we want to solve hamiltonicity in + + align:start position:0% +that we want to solve hamiltonicity in + + + align:start position:0% +that we want to solve hamiltonicity in +planer by partite Max degree 3 graphs + + align:start position:0% +planer by partite Max degree 3 graphs + + + align:start position:0% +planer by partite Max degree 3 graphs +and we're going to convert such a planer + + align:start position:0% +and we're going to convert such a planer + + + align:start position:0% +and we're going to convert such a planer +bipartite Max degree 3 graph into uh a + + align:start position:0% +bipartite Max degree 3 graph into uh a + + + align:start position:0% +bipartite Max degree 3 graph into uh a +grid graph that acts the + + align:start position:0% + + + + align:start position:0% + +same + + align:start position:0% +same + + + align:start position:0% +same +so + + align:start position:0% +so + + + align:start position:0% +so +um the first step is to draw the graph + + align:start position:0% +um the first step is to draw the graph + + + align:start position:0% +um the first step is to draw the graph +on a grd okay that's pretty pretty + + align:start position:0% +on a grd okay that's pretty pretty + + + align:start position:0% +on a grd okay that's pretty pretty +obvious + + align:start position:0% +obvious + + + align:start position:0% +obvious +um so here here's an example of what we + + align:start position:0% +um so here here's an example of what we + + + align:start position:0% +um so here here's an example of what we +want to do and then this is a picture of + + align:start position:0% +want to do and then this is a picture of + + + align:start position:0% +want to do and then this is a picture of +how to do it suppose you have a + + align:start position:0% +how to do it suppose you have a + + + align:start position:0% +how to do it suppose you have a +bipartite planer graph it's not obvious + + align:start position:0% +bipartite planer graph it's not obvious + + + align:start position:0% +bipartite planer graph it's not obvious +this is planer but it's obvious that + + align:start position:0% +this is planer but it's obvious that + + + align:start position:0% +this is planer but it's obvious that +it's bipartite it happens to be planer + + align:start position:0% +it's bipartite it happens to be planer + + + align:start position:0% +it's bipartite it happens to be planer +it's Max degree 3 and we want the + + align:start position:0% +it's Max degree 3 and we want the + + + align:start position:0% +it's Max degree 3 and we want the +vertices are labeled the X eyes and the + + align:start position:0% +vertices are labeled the X eyes and the + + + align:start position:0% +vertices are labeled the X eyes and the +Y eyes and you can see the corresponding + + align:start position:0% +Y eyes and you can see the corresponding + + + align:start position:0% +Y eyes and you can see the corresponding +labeling here so not all of the grid + + align:start position:0% +labeling here so not all of the grid + + + align:start position:0% +labeling here so not all of the grid +dots are going to be labeled some of + + align:start position:0% +dots are going to be labeled some of + + + align:start position:0% +dots are going to be labeled some of +them are just auxiliary in order to + + align:start position:0% +them are just auxiliary in order to + + + align:start position:0% +them are just auxiliary in order to +connect two vertices we're going to have + + align:start position:0% +connect two vertices we're going to have + + + align:start position:0% +connect two vertices we're going to have +to draw paths orthogonal paths on the + + align:start position:0% +to draw paths orthogonal paths on the + + + align:start position:0% +to draw paths orthogonal paths on the +grid + + align:start position:0% +grid + + + align:start position:0% +grid +uh but the key thing I want is that uh + + align:start position:0% +uh but the key thing I want is that uh + + + align:start position:0% +uh but the key thing I want is that uh +the square grid has a two coloring + + align:start position:0% +the square grid has a two coloring + + + align:start position:0% +the square grid has a two coloring +inherently and I want that two coloring + + align:start position:0% +inherently and I want that two coloring + + + align:start position:0% +inherently and I want that two coloring +to match this two coloring okay that's + + align:start position:0% +to match this two coloring okay that's + + + align:start position:0% +to match this two coloring okay that's +what I would call a parody preserving + + align:start position:0% +what I would call a parody preserving + + + align:start position:0% +what I would call a parody preserving +embedding of the + + align:start position:0% +embedding of the + + + align:start position:0% +embedding of the +graph uh how uh and you can see in this + + align:start position:0% +graph uh how uh and you can see in this + + + align:start position:0% +graph uh how uh and you can see in this +example the three x eyes are white and + + align:start position:0% +example the three x eyes are white and + + + align:start position:0% +example the three x eyes are white and +the three y eyes are black and if you + + align:start position:0% +the three y eyes are black and if you + + + align:start position:0% +the three y eyes are black and if you +check all the edges they should + + align:start position:0% +check all the edges they should + + + align:start position:0% +check all the edges they should +correspond just ignore the dash lines + + align:start position:0% +correspond just ignore the dash lines + + + align:start position:0% +correspond just ignore the dash lines +that's to show you the grid underlying + + align:start position:0% +that's to show you the grid underlying + + + align:start position:0% +that's to show you the grid underlying +uh so this is a valid embedding how do + + align:start position:0% +uh so this is a valid embedding how do + + + align:start position:0% +uh so this is a valid embedding how do +we do it well we just take any embedding + + align:start position:0% +we do it well we just take any embedding + + + align:start position:0% +we do it well we just take any embedding +in in the grid uh it's well known that + + align:start position:0% +in in the grid uh it's well known that + + + align:start position:0% +in in the grid uh it's well known that +if you have a Max deegree 4 graph you + + align:start position:0% +if you have a Max deegree 4 graph you + + + align:start position:0% +if you have a Max deegree 4 graph you +can draw it in the grid without + + align:start position:0% +can draw it in the grid without + + + align:start position:0% +can draw it in the grid without +Crossings and each Edge is some + + align:start position:0% +Crossings and each Edge is some + + + align:start position:0% +Crossings and each Edge is some +orthogonal + + align:start position:0% +orthogonal + + + align:start position:0% +orthogonal +polyline + + align:start position:0% +polyline + + + align:start position:0% +polyline +uh I won't prove that here and then um + + align:start position:0% +uh I won't prove that here and then um + + + align:start position:0% +uh I won't prove that here and then um +suppose the parody is wrong for some + + align:start position:0% +suppose the parody is wrong for some + + + align:start position:0% +suppose the parody is wrong for some +vertex suppose you draw a Vertex V and + + align:start position:0% +vertex suppose you draw a Vertex V and + + + align:start position:0% +vertex suppose you draw a Vertex V and +it happens to be black but you want it + + align:start position:0% +it happens to be black but you want it + + + align:start position:0% +it happens to be black but you want it +to be white then I'm just going to shift + + align:start position:0% +to be white then I'm just going to shift + + + align:start position:0% +to be white then I'm just going to shift +it over by one and do these kinds of + + align:start position:0% +it over by one and do these kinds of + + + align:start position:0% +it over by one and do these kinds of +Wiggles and that's it so you uh scale + + align:start position:0% +Wiggles and that's it so you uh scale + + + align:start position:0% +Wiggles and that's it so you uh scale +everything by a factor of three and + + align:start position:0% +everything by a factor of three and + + + align:start position:0% +everything by a factor of three and +you'll have room to do those Wiggles uh + + align:start position:0% +you'll have room to do those Wiggles uh + + + align:start position:0% +you'll have room to do those Wiggles uh +so you take an arbitrary orthogonal grid + + align:start position:0% +so you take an arbitrary orthogonal grid + + + align:start position:0% +so you take an arbitrary orthogonal grid +drawing and then uh add The Wiggles and + + align:start position:0% +drawing and then uh add The Wiggles and + + + align:start position:0% +drawing and then uh add The Wiggles and +you get whenever things are in the wrong + + align:start position:0% +you get whenever things are in the wrong + + + align:start position:0% +you get whenever things are in the wrong +parody and now every vertex will be in + + align:start position:0% +parody and now every vertex will be in + + + align:start position:0% +parody and now every vertex will be in +the correct parody okay that will be + + align:start position:0% +the correct parody okay that will be + + + align:start position:0% +the correct parody okay that will be +crucial for the + + align:start position:0% +crucial for the + + + align:start position:0% +crucial for the +reduction so at this point we've got an + + align:start position:0% +reduction so at this point we've got an + + + align:start position:0% +reduction so at this point we've got an +orthogonal sorry we've got an orthogonal + + align:start position:0% +orthogonal sorry we've got an orthogonal + + + align:start position:0% +orthogonal sorry we've got an orthogonal +parody preserving drawing of our given + + align:start position:0% +parody preserving drawing of our given + + + align:start position:0% +parody preserving drawing of our given +bipartite planer Max degree 3 graph and + + align:start position:0% +bipartite planer Max degree 3 graph and + + + align:start position:0% +bipartite planer Max degree 3 graph and +uh the issue is there sort of two types + + align:start position:0% +uh the issue is there sort of two types + + + align:start position:0% +uh the issue is there sort of two types +of vertices here there's the ones that + + align:start position:0% +of vertices here there's the ones that + + + align:start position:0% +of vertices here there's the ones that +we really need to visit and then there's + + align:start position:0% +we really need to visit and then there's + + + align:start position:0% +we really need to visit and then there's +these other vertices which are + + align:start position:0% +these other vertices which are + + + align:start position:0% +these other vertices which are +representing edges we don't need to + + align:start position:0% +representing edges we don't need to + + + align:start position:0% +representing edges we don't need to +visit every Edge that's the or tour + + align:start position:0% +visit every Edge that's the or tour + + + align:start position:0% +visit every Edge that's the or tour +problem hamiltonian tour we just need to + + align:start position:0% +problem hamiltonian tour we just need to + + + align:start position:0% +problem hamiltonian tour we just need to +visit every vertex which are the labeled + + align:start position:0% +visit every vertex which are the labeled + + + align:start position:0% +visit every vertex which are the labeled +dots over + + align:start position:0% +dots over + + + align:start position:0% +dots over +here so this is where things get + + align:start position:0% +here so this is where things get + + + align:start position:0% +here so this is where things get +fun uh here is a key Gadget before we + + align:start position:0% +fun uh here is a key Gadget before we + + + align:start position:0% +fun uh here is a key Gadget before we +see the overall + + align:start position:0% +see the overall + + + align:start position:0% +see the overall +architecture uh these are called + + align:start position:0% +architecture uh these are called + + + align:start position:0% +architecture uh these are called +tentacles in the original paper I'm + + align:start position:0% +tentacles in the original paper I'm + + + align:start position:0% +tentacles in the original paper I'm +calling them Edge gadgets because + + align:start position:0% +calling them Edge gadgets because + + + align:start position:0% +calling them Edge gadgets because +they're just simulating a single edge of + + align:start position:0% +they're just simulating a single edge of + + + align:start position:0% +they're just simulating a single edge of +the original graph but tentacles is + + align:start position:0% +the original graph but tentacles is + + + align:start position:0% +the original graph but tentacles is +cooler whichever you prefer uh so uh I + + align:start position:0% +cooler whichever you prefer uh so uh I + + + align:start position:0% +cooler whichever you prefer uh so uh I +mean these are the dots that haven't all + + align:start position:0% +mean these are the dots that haven't all + + + align:start position:0% +mean these are the dots that haven't all +been drawn explicitly here uh and so + + align:start position:0% +been drawn explicitly here uh and so + + + align:start position:0% +been drawn explicitly here uh and so +it's just like a 2xn sort of corridor + + align:start position:0% +it's just like a 2xn sort of corridor + + + align:start position:0% +it's just like a 2xn sort of corridor +the base version would be this uh but + + align:start position:0% +the base version would be this uh but + + + align:start position:0% +the base version would be this uh but +the if you want to have turns which + + align:start position:0% +the if you want to have turns which + + + align:start position:0% +the if you want to have turns which +we're going to need 90° turns it looks + + align:start position:0% +we're going to need 90° turns it looks + + + align:start position:0% +we're going to need 90° turns it looks +more like + + align:start position:0% +more like + + + align:start position:0% +more like +this and there's basically two ways to + + align:start position:0% +this and there's basically two ways to + + + align:start position:0% +this and there's basically two ways to +cover this sort of three ways but the + + align:start position:0% +cover this sort of three ways but the + + + align:start position:0% +cover this sort of three ways but the +way parody will work out there will only + + align:start position:0% +way parody will work out there will only + + + align:start position:0% +way parody will work out there will only +be two ways that we care about this is + + align:start position:0% +be two ways that we care about this is + + + align:start position:0% +be two ways that we care about this is +not a variable Gadget okay it's it looks + + align:start position:0% +not a variable Gadget okay it's it looks + + + align:start position:0% +not a variable Gadget okay it's it looks +like kind of maybe a variable Gadget but + + align:start position:0% +like kind of maybe a variable Gadget but + + + align:start position:0% +like kind of maybe a variable Gadget but +that's not how we're using it uh so one + + align:start position:0% +that's not how we're using it uh so one + + + align:start position:0% +that's not how we're using it uh so one +way you can visit this gadget is to + + align:start position:0% +way you can visit this gadget is to + + + align:start position:0% +way you can visit this gadget is to +zigzag like this we've seen this in + + align:start position:0% +zigzag like this we've seen this in + + + align:start position:0% +zigzag like this we've seen this in +pretty much all of our hamiltonicity + + align:start position:0% +pretty much all of our hamiltonicity + + + align:start position:0% +pretty much all of our hamiltonicity +planer hamiltonicity proof so that's the + + align:start position:0% +planer hamiltonicity proof so that's the + + + align:start position:0% +planer hamiltonicity proof so that's the +core idea is the same uh you could start + + align:start position:0% +core idea is the same uh you could start + + + align:start position:0% +core idea is the same uh you could start +at a and end at C or you could start at + + align:start position:0% +at a and end at C or you could start at + + + align:start position:0% +at a and end at C or you could start at +b and end at D and that's true in this + + align:start position:0% +b and end at D and that's true in this + + + align:start position:0% +b and end at D and that's true in this +version as well once you start + + align:start position:0% +version as well once you start + + + align:start position:0% +version as well once you start +alternating you're forced to alternate + + align:start position:0% +alternating you're forced to alternate + + + align:start position:0% +alternating you're forced to alternate +all the way through so you could imagine + + align:start position:0% +all the way through so you could imagine + + + align:start position:0% +all the way through so you could imagine +using that for a wire but we're not + + align:start position:0% +using that for a wire but we're not + + + align:start position:0% +using that for a wire but we're not +going to use the two alternations by + + align:start position:0% +going to use the two alternations by + + + align:start position:0% +going to use the two alternations by +parody we'll be forced to do it one way + + align:start position:0% +parody we'll be forced to do it one way + + + align:start position:0% +parody we'll be forced to do it one way +or the other we'll be told whether we're + + align:start position:0% +or the other we'll be told whether we're + + + align:start position:0% +or the other we'll be told whether we're +starting or ending at one of + + align:start position:0% +starting or ending at one of + + + align:start position:0% +starting or ending at one of +them uh I think well it won't matter but + + align:start position:0% +them uh I think well it won't matter but + + + align:start position:0% +them uh I think well it won't matter but +there's this other way you could visit + + align:start position:0% +there's this other way you could visit + + + align:start position:0% +there's this other way you could visit +which is to just go all the way down and + + align:start position:0% +which is to just go all the way down and + + + align:start position:0% +which is to just go all the way down and +then come all the way + + align:start position:0% +then come all the way + + + align:start position:0% +then come all the way +back okay uh this is going to correspond + + align:start position:0% +back okay uh this is going to correspond + + + align:start position:0% +back okay uh this is going to correspond +to an edge that is in the hamiltonian + + align:start position:0% +to an edge that is in the hamiltonian + + + align:start position:0% +to an edge that is in the hamiltonian +cycle because I want to start at some + + align:start position:0% +cycle because I want to start at some + + + align:start position:0% +cycle because I want to start at some +vertex up here and I want end at some + + align:start position:0% +vertex up here and I want end at some + + + align:start position:0% +vertex up here and I want end at some +vertex down here if I follow the edge + + align:start position:0% +vertex down here if I follow the edge + + + align:start position:0% +vertex down here if I follow the edge +this is going to correspond to an edge + + align:start position:0% +this is going to correspond to an edge + + + align:start position:0% +this is going to correspond to an edge +that we don't + + align:start position:0% +that we don't + + + align:start position:0% +that we don't +use right because um at this vertex I I + + align:start position:0% +use right because um at this vertex I I + + + align:start position:0% +use right because um at this vertex I I +still need to cover these vertices + + align:start position:0% +still need to cover these vertices + + + align:start position:0% +still need to cover these vertices +somehow but I don't want that to really + + align:start position:0% +somehow but I don't want that to really + + + align:start position:0% +somehow but I don't want that to really +matter I want this Edge to be coverable + + align:start position:0% +matter I want this Edge to be coverable + + + align:start position:0% +matter I want this Edge to be coverable +for free and so the idea is as I visit + + align:start position:0% +for free and so the idea is as I visit + + + align:start position:0% +for free and so the idea is as I visit +this vertex we're just going to ZIP down + + align:start position:0% +this vertex we're just going to ZIP down + + + align:start position:0% +this vertex we're just going to ZIP down +here zip back up and all these vertices + + align:start position:0% +here zip back up and all these vertices + + + align:start position:0% +here zip back up and all these vertices +get visited uh for free okay it's not + + align:start position:0% +get visited uh for free okay it's not + + + align:start position:0% +get visited uh for free okay it's not +really part of the + + align:start position:0% +really part of the + + + align:start position:0% +really part of the +tour let me show you in some more detail + + align:start position:0% +tour let me show you in some more detail + + + align:start position:0% +tour let me show you in some more detail +uh here's what a Vertex looks like + + align:start position:0% +uh here's what a Vertex looks like + + + align:start position:0% +uh here's what a Vertex looks like +vertex is just going to be a 3X3 grid of + + align:start position:0% +vertex is just going to be a 3X3 grid of + + + align:start position:0% +vertex is just going to be a 3X3 grid of +dots uh now remember there are two kinds + + align:start position:0% +dots uh now remember there are two kinds + + + align:start position:0% +dots uh now remember there are two kinds +of vertices there's the ones that were + + align:start position:0% +of vertices there's the ones that were + + + align:start position:0% +of vertices there's the ones that were +um so again we're expanding everything + + align:start position:0% +um so again we're expanding everything + + + align:start position:0% +um so again we're expanding everything +for this to work out there the vertices + + align:start position:0% +for this to work out there the vertices + + + align:start position:0% +for this to work out there the vertices +that were originally White and the + + align:start position:0% +that were originally White and the + + + align:start position:0% +that were originally White and the +vertices that were originally black + + align:start position:0% +vertices that were originally black + + + align:start position:0% +vertices that were originally black +doesn't matter which is which but + + align:start position:0% +doesn't matter which is which but + + + align:start position:0% +doesn't matter which is which but +there's two classes of vertices and + + align:start position:0% +there's two classes of vertices and + + + align:start position:0% +there's two classes of vertices and +we're going to attach the edge + + align:start position:0% +we're going to attach the edge + + + align:start position:0% +we're going to attach the edge +gadgets which were these 2xn kind of + + align:start position:0% +gadgets which were these 2xn kind of + + + align:start position:0% +gadgets which were these 2xn kind of +things uh so here this is all Edge + + align:start position:0% +things uh so here this is all Edge + + + align:start position:0% +things uh so here this is all Edge +Gadget here we're going to attach it to + + align:start position:0% +Gadget here we're going to attach it to + + + align:start position:0% +Gadget here we're going to attach it to +a Vertex that's white in this sort of + + align:start position:0% +a Vertex that's white in this sort of + + + align:start position:0% +a Vertex that's white in this sort of +flush uh length two connection so here + + align:start position:0% +flush uh length two connection so here + + + align:start position:0% +flush uh length two connection so here +this is the variable up here this 3x3 + + align:start position:0% +this is the variable up here this 3x3 + + + align:start position:0% +this is the variable up here this 3x3 +thing and here we're add we're having + + align:start position:0% +thing and here we're add we're having + + + align:start position:0% +thing and here we're add we're having +two edges connecting to the The Edge + + align:start position:0% +two edges connecting to the The Edge + + + align:start position:0% +two edges connecting to the The Edge +gadget for the black vertices we're only + + align:start position:0% +gadget for the black vertices we're only + + + align:start position:0% +gadget for the black vertices we're only +going to have a single edge connecting + + align:start position:0% +going to have a single edge connecting + + + align:start position:0% +going to have a single edge connecting +them this is called a pin + + align:start position:0% +them this is called a pin + + + align:start position:0% +them this is called a pin +connection uh between the wire Gadget or + + align:start position:0% +connection uh between the wire Gadget or + + + align:start position:0% +connection uh between the wire Gadget or +the tentacle and the 3X3 down + + align:start position:0% +the tentacle and the 3X3 down + + + align:start position:0% +the tentacle and the 3X3 down +here okay + + align:start position:0% +here okay + + + align:start position:0% +here okay +y uh + + align:start position:0% +y uh + + + align:start position:0% +y uh +cuz um so here let's consider two + + align:start position:0% +cuz um so here let's consider two + + + align:start position:0% +cuz um so here let's consider two +vertices that are attached by an edge uh + + align:start position:0% +vertices that are attached by an edge uh + + + align:start position:0% +vertices that are attached by an edge uh +so they have opposite parity On's I've + + align:start position:0% +so they have opposite parity On's I've + + + align:start position:0% +so they have opposite parity On's I've +forgotten which is which this is white + + align:start position:0% +forgotten which is which this is white + + + align:start position:0% +forgotten which is which this is white +and this is black I think uh here we + + align:start position:0% +and this is black I think uh here we + + + align:start position:0% +and this is black I think uh here we +have the pin connection here we have the + + align:start position:0% +have the pin connection here we have the + + + align:start position:0% +have the pin connection here we have the +length two connection uh and the idea is + + align:start position:0% +length two connection uh and the idea is + + + align:start position:0% +length two connection uh and the idea is +there's exactly two ways to Traverse + + align:start position:0% +there's exactly two ways to Traverse + + + align:start position:0% +there's exactly two ways to Traverse +this Edge as we saw but now you can see + + align:start position:0% +this Edge as we saw but now you can see + + + align:start position:0% +this Edge as we saw but now you can see +the connections let me put it that way + + align:start position:0% +the connections let me put it that way + + + align:start position:0% +the connections let me put it that way +so the idea is well maybe you choose to + + align:start position:0% +so the idea is well maybe you choose to + + + align:start position:0% +so the idea is well maybe you choose to +use that edge in the cycle and so I want + + align:start position:0% +use that edge in the cycle and so I want + + + align:start position:0% +use that edge in the cycle and so I want +to be able to just Traverse it + + align:start position:0% +to be able to just Traverse it + + + align:start position:0% +to be able to just Traverse it +everything is good and so here I know + + align:start position:0% +everything is good and so here I know + + + align:start position:0% +everything is good and so here I know +that I'm entering at this point which + + align:start position:0% +that I'm entering at this point which + + + align:start position:0% +that I'm entering at this point which +means I know they'll have to be exiting + + align:start position:0% +means I know they'll have to be exiting + + + align:start position:0% +means I know they'll have to be exiting +here so the parodies are forced that + + align:start position:0% +here so the parodies are forced that + + + align:start position:0% +here so the parodies are forced that +case the zigzag parody is + + align:start position:0% +case the zigzag parody is + + + align:start position:0% +case the zigzag parody is +forced the other possibility uh because + + align:start position:0% +forced the other possibility uh because + + + align:start position:0% +forced the other possibility uh because +there's only one connection here you + + align:start position:0% +there's only one connection here you + + + align:start position:0% +there's only one connection here you +couldn't Traverse this way and then come + + align:start position:0% +couldn't Traverse this way and then come + + + align:start position:0% +couldn't Traverse this way and then come +back uh but from this side you could + + align:start position:0% +back uh but from this side you could + + + align:start position:0% +back uh but from this side you could +Traverse and then come back and it + + align:start position:0% +Traverse and then come back and it + + + align:start position:0% +Traverse and then come back and it +doesn't touch the ver Tex at all so the + + align:start position:0% +doesn't touch the ver Tex at all so the + + + align:start position:0% +doesn't touch the ver Tex at all so the +idea is you could ignore this Edge + + align:start position:0% +idea is you could ignore this Edge + + + align:start position:0% +idea is you could ignore this Edge +entirely and it gets covered for free + + align:start position:0% +entirely and it gets covered for free + + + align:start position:0% +entirely and it gets covered for free +provided once you erase this this Edge + + align:start position:0% +provided once you erase this this Edge + + + align:start position:0% +provided once you erase this this Edge +is in the hamiltonian tour and at this + + align:start position:0% +is in the hamiltonian tour and at this + + + align:start position:0% +is in the hamiltonian tour and at this +point I should mention the what all this + + align:start position:0% +point I should mention the what all this + + + align:start position:0% +point I should mention the what all this +labeling means on the vertex Gadget the + + align:start position:0% +labeling means on the vertex Gadget the + + + align:start position:0% +labeling means on the vertex Gadget the +idea is for this vertex if you start at + + align:start position:0% +idea is for this vertex if you start at + + + align:start position:0% +idea is for this vertex if you start at +any of the pis any of the Four + + align:start position:0% +any of the pis any of the Four + + + align:start position:0% +any of the pis any of the Four +Corners any of the private investigators + + align:start position:0% +Corners any of the private investigators + + + align:start position:0% +Corners any of the private investigators +then uh you can end at any other Pi PJ + + align:start position:0% +then uh you can end at any other Pi PJ + + + align:start position:0% +then uh you can end at any other Pi PJ +um in such a way that you visit all + + align:start position:0% +um in such a way that you visit all + + + align:start position:0% +um in such a way that you visit all +three of the + + align:start position:0% + + + + align:start position:0% + +Eis there are four of them there are + + align:start position:0% +Eis there are four of them there are + + + align:start position:0% +Eis there are four of them there are +four of them EI EO EI EO no okay um so + + align:start position:0% +four of them EI EO EI EO no okay um so + + + align:start position:0% +four of them EI EO EI EO no okay um so +you so me skip the to the point you can + + align:start position:0% +you so me skip the to the point you can + + + align:start position:0% +you so me skip the to the point you can +start at Pi end at PJ and visit all the + + align:start position:0% +start at Pi end at PJ and visit all the + + + align:start position:0% +start at Pi end at PJ and visit all the +vertices and all of the E all the e case + + align:start position:0% +vertices and all of the E all the e case + + + align:start position:0% +vertices and all of the E all the e case +Okay so for example if I want to go from + + align:start position:0% +Okay so for example if I want to go from + + + align:start position:0% +Okay so for example if I want to go from +here to here I can go like this + + align:start position:0% +here to here I can go like this + + + align:start position:0% +here to here I can go like this +visited all the edges if I want to go + + align:start position:0% +visited all the edges if I want to go + + + align:start position:0% +visited all the edges if I want to go +from here to here I can go like this + + align:start position:0% +from here to here I can go like this + + + align:start position:0% +from here to here I can go like this +visited all the vertices visited all the + + align:start position:0% +visited all the vertices visited all the + + + align:start position:0% +visited all the vertices visited all the +e so that's good because each of these e + + align:start position:0% +e so that's good because each of these e + + + align:start position:0% +e so that's good because each of these e +e is potentially attached to some to an + + align:start position:0% +e is potentially attached to some to an + + + align:start position:0% +e is potentially attached to some to an +edge Gadget and we might want to visit + + align:start position:0% +edge Gadget and we might want to visit + + + align:start position:0% +edge Gadget and we might want to visit +all of the things out there and come + + align:start position:0% +all of the things out there and come + + + align:start position:0% +all of the things out there and come +back + + align:start position:0% +back + + + align:start position:0% +back +okay so you see the the kind of the key + + align:start position:0% +okay so you see the the kind of the key + + + align:start position:0% +okay so you see the the kind of the key +thing uh the reason why we only want a + + align:start position:0% +thing uh the reason why we only want a + + + align:start position:0% +thing uh the reason why we only want a +pin connection here here is if we had a + + align:start position:0% +pin connection here here is if we had a + + + align:start position:0% +pin connection here here is if we had a +a a full connection with with two edges + + align:start position:0% +a a full connection with with two edges + + + align:start position:0% +a a full connection with with two edges +you might imagine that you come out here + + align:start position:0% +you might imagine that you come out here + + + align:start position:0% +you might imagine that you come out here +do something eventually do other stuff + + align:start position:0% +do something eventually do other stuff + + + align:start position:0% +do something eventually do other stuff +and then come back on this path but + + align:start position:0% +and then come back on this path but + + + align:start position:0% +and then come back on this path but +because we have a pin connection always + + align:start position:0% +because we have a pin connection always + + + align:start position:0% +because we have a pin connection always +on one of the two sides uh you can't you + + align:start position:0% +on one of the two sides uh you can't you + + + align:start position:0% +on one of the two sides uh you can't you +can't have two separate traversal paths + + align:start position:0% +can't have two separate traversal paths + + + align:start position:0% +can't have two separate traversal paths +you as soon as you get here you have to + + align:start position:0% +you as soon as you get here you have to + + + align:start position:0% +you as soon as you get here you have to +turn back around if you went this way + + align:start position:0% +turn back around if you went this way + + + align:start position:0% +turn back around if you went this way +then this guy would never be visitable + + align:start position:0% +then this guy would never be visitable + + + align:start position:0% +then this guy would never be visitable +in a + + align:start position:0% +in a + + + align:start position:0% +in a +cycle okay so that's the key thing this + + align:start position:0% +cycle okay so that's the key thing this + + + align:start position:0% +cycle okay so that's the key thing this +was one of the E and so the idea is you + + align:start position:0% +was one of the E and so the idea is you + + + align:start position:0% +was one of the E and so the idea is you +can completely forget about this path + + align:start position:0% +can completely forget about this path + + + align:start position:0% +can completely forget about this path +you can just think about going from one + + align:start position:0% +you can just think about going from one + + + align:start position:0% +you can just think about going from one +of these white vertices to another in + + align:start position:0% +of these white vertices to another in + + + align:start position:0% +of these white vertices to another in +general it's going to correspond to uh + + align:start position:0% +general it's going to correspond to uh + + + align:start position:0% +general it's going to correspond to uh +which Edge gadgets that vertex Gadget is + + align:start position:0% +which Edge gadgets that vertex Gadget is + + + align:start position:0% +which Edge gadgets that vertex Gadget is +connected + + align:start position:0% +connected + + + align:start position:0% +connected +to uh and yeah so you can go from one + + align:start position:0% +to uh and yeah so you can go from one + + + align:start position:0% +to uh and yeah so you can go from one +vertex to another you will visit this + + align:start position:0% +vertex to another you will visit this + + + align:start position:0% +vertex to another you will visit this +Edge and so you can add in this part if + + align:start position:0% +Edge and so you can add in this part if + + + align:start position:0% +Edge and so you can add in this part if +you don't use the edge if you do use the + + align:start position:0% +you don't use the edge if you do use the + + + align:start position:0% +you don't use the edge if you do use the +edge then this you'll be starting from + + align:start position:0% +edge then this you'll be starting from + + + align:start position:0% +edge then this you'll be starting from +one of these white vertices and you want + + align:start position:0% +one of these white vertices and you want + + + align:start position:0% +one of these white vertices and you want +to go to this one and then you'll follow + + align:start position:0% +to go to this one and then you'll follow + + + align:start position:0% +to go to this one and then you'll follow +this path and then you get to this + + align:start position:0% +this path and then you get to this + + + align:start position:0% +this path and then you get to this +vertex and you go from one of these + + align:start position:0% +vertex and you go from one of these + + + align:start position:0% +vertex and you go from one of these +black vertices to one one of the other + + align:start position:0% +black vertices to one one of the other + + + align:start position:0% +black vertices to one one of the other +four corners and so on question should + + align:start position:0% +four corners and so on question should + + + align:start position:0% +four corners and so on question should +that line of three white dots should the + + align:start position:0% +that line of three white dots should the + + + align:start position:0% +that line of three white dots should the +middle one be in yes this should be + + align:start position:0% +middle one be in yes this should be + + + align:start position:0% +middle one be in yes this should be +black it's not my fault it could be the + + align:start position:0% +black it's not my fault it could be the + + + align:start position:0% +black it's not my fault it could be the +scanner or it could be there's a this is + + align:start position:0% +scanner or it could be there's a this is + + + align:start position:0% +scanner or it could be there's a this is +a handdrawn figure as you might guess so + + align:start position:0% +a handdrawn figure as you might guess so + + + align:start position:0% +a handdrawn figure as you might guess so +yeah that should be black everything + + align:start position:0% +yeah that should be black everything + + + align:start position:0% +yeah that should be black everything +should alternate so you see there's uh + + align:start position:0% +should alternate so you see there's uh + + + align:start position:0% +should alternate so you see there's uh +you can tell the parity of the vertex + + align:start position:0% +you can tell the parity of the vertex + + + align:start position:0% +you can tell the parity of the vertex +based on the par the color of the + + align:start position:0% +based on the par the color of the + + + align:start position:0% +based on the par the color of the +corners any other + + align:start position:0% +corners any other + + + align:start position:0% +corners any other +questions about that proof + + align:start position:0% +questions about that proof + + + align:start position:0% +questions about that proof +okay um so this is pretty cool and I + + align:start position:0% +okay um so this is pretty cool and I + + + align:start position:0% +okay um so this is pretty cool and I +would say hamiltonicity in Grid graphs + + align:start position:0% +would say hamiltonicity in Grid graphs + + + align:start position:0% +would say hamiltonicity in Grid graphs +is used a lot for as a base problem for + + align:start position:0% +is used a lot for as a base problem for + + + align:start position:0% +is used a lot for as a base problem for +reductions in computational Geometry uh + + align:start position:0% +reductions in computational Geometry uh + + + align:start position:0% +reductions in computational Geometry uh +especially tour like problems and you + + align:start position:0% +especially tour like problems and you + + + align:start position:0% +especially tour like problems and you +you'll notice the theme uh every + + align:start position:0% +you'll notice the theme uh every + + + align:start position:0% +you'll notice the theme uh every +reduction so far except the very first + + align:start position:0% +reduction so far except the very first + + + align:start position:0% +reduction so far except the very first +one I guess was from one type of + + align:start position:0% +one I guess was from one type of + + + align:start position:0% +one I guess was from one type of +hamiltonian circuit to another type of + + align:start position:0% +hamiltonian circuit to another type of + + + align:start position:0% +hamiltonian circuit to another type of +hamiltonian circuit and this tends to be + + align:start position:0% +hamiltonian circuit and this tends to be + + + align:start position:0% +hamiltonian circuit and this tends to be +common that you can work within + + align:start position:0% +common that you can work within + + + align:start position:0% +common that you can work within +hamiltonian circuit and mod your graph + + align:start position:0% +hamiltonian circuit and mod your graph + + + align:start position:0% +hamiltonian circuit and mod your graph +in all sorts of ways to get to a very + + align:start position:0% +in all sorts of ways to get to a very + + + align:start position:0% +in all sorts of ways to get to a very +simplified version of hamiltonian + + align:start position:0% +simplified version of hamiltonian + + + align:start position:0% +simplified version of hamiltonian +circuit and that's cool and so you get a + + align:start position:0% +circuit and that's cool and so you get a + + + align:start position:0% +circuit and that's cool and so you get a +lot of mileage just within the + + align:start position:0% +lot of mileage just within the + + + align:start position:0% +lot of mileage just within the +hamiltonian Circuit Family + + align:start position:0% +hamiltonian Circuit Family + + + align:start position:0% +hamiltonian Circuit Family +um cool let me give you a couple of + + align:start position:0% +um cool let me give you a couple of + + + align:start position:0% +um cool let me give you a couple of +applications right off the bat what uh + + align:start position:0% +applications right off the bat what uh + + + align:start position:0% +applications right off the bat what uh +this is going back a little bit but are + + align:start position:0% +this is going back a little bit but are + + + align:start position:0% +this is going back a little bit but are +there any sort of natural families of + + align:start position:0% +there any sort of natural families of + + + align:start position:0% +there any sort of natural families of +graphs for which finding a hamiltonian + + align:start position:0% +graphs for which finding a hamiltonian + + + align:start position:0% +graphs for which finding a hamiltonian +path is strictly easier than finding a + + align:start position:0% +path is strictly easier than finding a + + + align:start position:0% +path is strictly easier than finding a +circle uh + + align:start position:0% +circle uh + + + align:start position:0% +circle uh +I think the only this problem would be + + align:start position:0% +I think the only this problem would be + + + align:start position:0% +I think the only this problem would be +easy find a hamiltonian path given a + + align:start position:0% +easy find a hamiltonian path given a + + + align:start position:0% +easy find a hamiltonian path given a +hamiltonian path but um I'm not aware of + + align:start position:0% +hamiltonian path but um I'm not aware of + + + align:start position:0% +hamiltonian path but um I'm not aware of +any other problems where one is where + + align:start position:0% +any other problems where one is where + + + align:start position:0% +any other problems where one is where +hamiltonian path is easier than cycle um + + align:start position:0% +hamiltonian path is easier than cycle um + + + align:start position:0% +hamiltonian path is easier than cycle um +I mean in general you can reduce one to + + align:start position:0% +I mean in general you can reduce one to + + + align:start position:0% +I mean in general you can reduce one to +the other somehow it's maybe a little + + align:start position:0% +the other somehow it's maybe a little + + + align:start position:0% +the other somehow it's maybe a little +tricky without the two given end points + + align:start position:0% +tricky without the two given end points + + + align:start position:0% +tricky without the two given end points +uh and if you have lots of structure + + align:start position:0% +uh and if you have lots of structure + + + align:start position:0% +uh and if you have lots of structure +like planarity and three regularity uh + + align:start position:0% +like planarity and three regularity uh + + + align:start position:0% +like planarity and three regularity uh +it's not so clear but definitely + + align:start position:0% +it's not so clear but definitely + + + align:start position:0% +it's not so clear but definitely +Hamilton Plum path is still hard in this + + align:start position:0% +Hamilton Plum path is still hard in this + + + align:start position:0% +Hamilton Plum path is still hard in this +problem I think one easy way to do that + + align:start position:0% +problem I think one easy way to do that + + + align:start position:0% +problem I think one easy way to do that +is uh to just do the same chain of + + align:start position:0% +is uh to just do the same chain of + + + align:start position:0% +is uh to just do the same chain of +reductions but start with hiltonium path + + align:start position:0% +reductions but start with hiltonium path + + + align:start position:0% +reductions but start with hiltonium path +instead of cycle and follow through and + + align:start position:0% +instead of cycle and follow through and + + + align:start position:0% +instead of cycle and follow through and +pretty much every step should still be + + align:start position:0% +pretty much every step should still be + + + align:start position:0% +pretty much every step should still be +path-based + + align:start position:0% +path-based + + + align:start position:0% +path-based +so uh that's actually useful we'll want + + align:start position:0% +so uh that's actually useful we'll want + + + align:start position:0% +so uh that's actually useful we'll want +hamiltonian path and grid graphs also at + + align:start position:0% +hamiltonian path and grid graphs also at + + + align:start position:0% +hamiltonian path and grid graphs also at +some point but what I showed was + + align:start position:0% +some point but what I showed was + + + align:start position:0% +some point but what I showed was +hamiltonian cycle yeah so pretty much + + align:start position:0% +hamiltonian cycle yeah so pretty much + + + align:start position:0% +hamiltonian cycle yeah so pretty much +everywhere they seem to be the same but + + align:start position:0% +everywhere they seem to be the same but + + + align:start position:0% +everywhere they seem to be the same but +it'd be cool to find an example where + + align:start position:0% +it'd be cool to find an example where + + + align:start position:0% +it'd be cool to find an example where +they have different complexity + + align:start position:0% +they have different complexity + + + align:start position:0% +they have different complexity +okay uh so here's another + + align:start position:0% +okay uh so here's another + + + align:start position:0% +okay uh so here's another +problem ukan + + align:start position:0% + + + + align:start position:0% + +tsp uh traveling salesman problem you're + + align:start position:0% +tsp uh traveling salesman problem you're + + + align:start position:0% +tsp uh traveling salesman problem you're +given a set of points in the + + align:start position:0% +given a set of points in the + + + align:start position:0% +given a set of points in the +plane better not make it too big because + + align:start position:0% +plane better not make it too big because + + + align:start position:0% +plane better not make it too big because +this is n hard um and I want to find a + + align:start position:0% +this is n hard um and I want to find a + + + align:start position:0% +this is n hard um and I want to find a +tour it visits every point exactly once + + align:start position:0% +tour it visits every point exactly once + + + align:start position:0% +tour it visits every point exactly once +and has minimum total length ukan length + + align:start position:0% +and has minimum total length ukan length + + + align:start position:0% +and has minimum total length ukan length +so it's the usual notion of + + align:start position:0% +so it's the usual notion of + + + align:start position:0% +so it's the usual notion of +length uh I claim this is NP hard now + + align:start position:0% +length uh I claim this is NP hard now + + + align:start position:0% +length uh I claim this is NP hard now +this is a little scary most of the + + align:start position:0% +this is a little scary most of the + + + align:start position:0% +this is a little scary most of the +problems we've been working with are + + align:start position:0% +problems we've been working with are + + + align:start position:0% +problems we've been working with are +very discreet I mean the output here is + + align:start position:0% +very discreet I mean the output here is + + + align:start position:0% +very discreet I mean the output here is +sort of discret you choose a permutation + + align:start position:0% +sort of discret you choose a permutation + + + align:start position:0% +sort of discret you choose a permutation +on the points uh but there's sort of it + + align:start position:0% +on the points uh but there's sort of it + + + align:start position:0% +on the points uh but there's sort of it +feels like there's almost no control + + align:start position:0% +feels like there's almost no control + + + align:start position:0% +feels like there's almost no control +here I mean how would I construct + + align:start position:0% +here I mean how would I construct + + + align:start position:0% +here I mean how would I construct +localized gadgets when I can just jump + + align:start position:0% +localized gadgets when I can just jump + + + align:start position:0% +localized gadgets when I can just jump +from any point to any other point at any + + align:start position:0% +from any point to any other point at any + + + align:start position:0% +from any point to any other point at any +time as long as that point hasn't + + align:start position:0% +time as long as that point hasn't + + + align:start position:0% +time as long as that point hasn't +already been + + align:start position:0% +already been + + + align:start position:0% +already been +used but it's really easy to prove this + + align:start position:0% +used but it's really easy to prove this + + + align:start position:0% +used but it's really easy to prove this +is NP hard given what we just did oh I + + align:start position:0% +is NP hard given what we just did oh I + + + align:start position:0% +is NP hard given what we just did oh I +should say um here's a a full worked out + + align:start position:0% +should say um here's a a full worked out + + + align:start position:0% +should say um here's a a full worked out +example so this is what I should be + + align:start position:0% +example so this is what I should be + + + align:start position:0% +example so this is what I should be +pointing at this was the parity + + align:start position:0% +pointing at this was the parity + + + align:start position:0% +pointing at this was the parity +preserving uh graph that we uh Drew + + align:start position:0% +preserving uh graph that we uh Drew + + + align:start position:0% +preserving uh graph that we uh Drew +before and this is what you get in the + + align:start position:0% +before and this is what you get in the + + + align:start position:0% +before and this is what you get in the +reduction uh along with an actual + + align:start position:0% +reduction uh along with an actual + + + align:start position:0% +reduction uh along with an actual +solution which is the one drawn in + + align:start position:0% +solution which is the one drawn in + + + align:start position:0% +solution which is the one drawn in +Orange + + align:start position:0% +Orange + + + align:start position:0% +Orange +here uh so you can see you can read that + + align:start position:0% +here uh so you can see you can read that + + + align:start position:0% +here uh so you can see you can read that +off because wherever you see zigzags + + align:start position:0% +off because wherever you see zigzags + + + align:start position:0% +off because wherever you see zigzags +that's where you're using the path here + + align:start position:0% +that's where you're using the path here + + + align:start position:0% +that's where you're using the path here +so these correspond and then this + + align:start position:0% +so these correspond and then this + + + align:start position:0% +so these correspond and then this +corresponds right and then up and over + + align:start position:0% +corresponds right and then up and over + + + align:start position:0% +corresponds right and then up and over +and then the the unused edges the the + + align:start position:0% +and then the the unused edges the the + + + align:start position:0% +and then the the unused edges the the +not orange ones that's where we get + + align:start position:0% +not orange ones that's where we get + + + align:start position:0% +not orange ones that's where we get +these kinds of Loops uh starting from + + align:start position:0% +these kinds of Loops uh starting from + + + align:start position:0% +these kinds of Loops uh starting from +the uh vertices of one parody I guess + + align:start position:0% +the uh vertices of one parody I guess + + + align:start position:0% +the uh vertices of one parody I guess +the white ones and then going to the + + align:start position:0% +the white ones and then going to the + + + align:start position:0% +the white ones and then going to the +black ones and turning around at the pin + + align:start position:0% +black ones and turning around at the pin + + + align:start position:0% +black ones and turning around at the pin +joint cool so uh given that this is hard + + align:start position:0% +joint cool so uh given that this is hard + + + align:start position:0% +joint cool so uh given that this is hard +why is this hard + + align:start position:0% + + + + align:start position:0% + +uh so the decision problem let's say is + + align:start position:0% +uh so the decision problem let's say is + + + align:start position:0% +uh so the decision problem let's say is +I give you a set of points I give you + + align:start position:0% +I give you a set of points I give you + + + align:start position:0% +I give you a set of points I give you +the length the desired length of the + + align:start position:0% +the length the desired length of the + + + align:start position:0% +the length the desired length of the +tour I want to know is there a tour + + align:start position:0% +tour I want to know is there a tour + + + align:start position:0% +tour I want to know is there a tour +visits every point exactly once and has + + align:start position:0% +visits every point exactly once and has + + + align:start position:0% +visits every point exactly once and has +length at most that given + + align:start position:0% +length at most that given + + + align:start position:0% +length at most that given +length right so if you look at uh some + + align:start position:0% +length right so if you look at uh some + + + align:start position:0% +length right so if you look at uh some +grid craft it'll have some number of + + align:start position:0% +grid craft it'll have some number of + + + align:start position:0% +grid craft it'll have some number of +nodes which means the tour would have to + + align:start position:0% +nodes which means the tour would have to + + + align:start position:0% +nodes which means the tour would have to +necessarily have if you just choose + + align:start position:0% +necessarily have if you just choose + + + align:start position:0% +necessarily have if you just choose +those points the T would necessarily + + align:start position:0% +those points the T would necessarily + + + align:start position:0% +those points the T would necessarily +have at least exactly that + + align:start position:0% +have at least exactly that + + + align:start position:0% +have at least exactly that +edges and each Edge would have to have + + align:start position:0% +edges and each Edge would have to have + + + align:start position:0% +edges and each Edge would have to have +length at least one because the Clos + + align:start position:0% +length at least one because the Clos + + + align:start position:0% +length at least one because the Clos +pair of points is uh one apart Y and so + + align:start position:0% +pair of points is uh one apart Y and so + + + align:start position:0% +pair of points is uh one apart Y and so +if you just count the number of points + + align:start position:0% +if you just count the number of points + + + align:start position:0% +if you just count the number of points +and say that that's the desired uh + + align:start position:0% +and say that that's the desired uh + + + align:start position:0% +and say that that's the desired uh +length of your tour then you can only do + + align:start position:0% +length of your tour then you can only do + + + align:start position:0% +length of your tour then you can only do +that if you can get through this by + + align:start position:0% +that if you can get through this by + + + align:start position:0% +that if you can get through this by +following only edges that are length + + align:start position:0% +following only edges that are length + + + align:start position:0% +following only edges that are length +exactly so we're going to reduce from + + align:start position:0% +exactly so we're going to reduce from + + + align:start position:0% +exactly so we're going to reduce from +this + + align:start position:0% +this + + + align:start position:0% +this +problem given such a grid graph the + + align:start position:0% +problem given such a grid graph the + + + align:start position:0% +problem given such a grid graph the +reduction just looks at the vertices + + align:start position:0% +reduction just looks at the vertices + + + align:start position:0% +reduction just looks at the vertices +throws away the edges that is our input + + align:start position:0% +throws away the edges that is our input + + + align:start position:0% +throws away the edges that is our input +those points are the input to tsp then + + align:start position:0% +those points are the input to tsp then + + + align:start position:0% +those points are the input to tsp then +the claim is that every tour let's say + + align:start position:0% +the claim is that every tour let's say + + + align:start position:0% +the claim is that every tour let's say +there are end points in this picture + + align:start position:0% +there are end points in this picture + + + align:start position:0% +there are end points in this picture +every tour has to have length at least n + + align:start position:0% +every tour has to have length at least n + + + align:start position:0% +every tour has to have length at least n +as you said because they're end points + + align:start position:0% +as you said because they're end points + + + align:start position:0% +as you said because they're end points +the total number of edges is n in a + + align:start position:0% +the total number of edges is n in a + + + align:start position:0% +the total number of edges is n in a +cycle hamiltonian cycle and uh every + + align:start position:0% +cycle hamiltonian cycle and uh every + + + align:start position:0% +cycle hamiltonian cycle and uh every +Edge must have length at least one + + align:start position:0% +Edge must have length at least one + + + align:start position:0% +Edge must have length at least one +because that's the nearest pair uh and + + align:start position:0% +because that's the nearest pair uh and + + + align:start position:0% +because that's the nearest pair uh and +so that's a lower bound and then on the + + align:start position:0% +so that's a lower bound and then on the + + + align:start position:0% +so that's a lower bound and then on the +other hand if there is a tour uh that + + align:start position:0% +other hand if there is a tour uh that + + + align:start position:0% +other hand if there is a tour uh that +has length only n then it must actually + + align:start position:0% +has length only n then it must actually + + + align:start position:0% +has length only n then it must actually +be a hamian cycle in this graph because + + align:start position:0% +be a hamian cycle in this graph because + + + align:start position:0% +be a hamian cycle in this graph because +that you're then you're only using edges + + align:start position:0% +that you're then you're only using edges + + + align:start position:0% +that you're then you're only using edges +that exist in the grid graph so it's + + align:start position:0% +that exist in the grid graph so it's + + + align:start position:0% +that exist in the grid graph so it's +really the same problem ukian tsp really + + align:start position:0% +really the same problem ukian tsp really + + + align:start position:0% +really the same problem ukian tsp really +is a special case of + + align:start position:0% +is a special case of + + + align:start position:0% +is a special case of +this + + align:start position:0% +this + + + align:start position:0% +this +uh which is + + align:start position:0% +uh which is + + + align:start position:0% +uh which is +cool this problem was proved hard much + + align:start position:0% +cool this problem was proved hard much + + + align:start position:0% +cool this problem was proved hard much +earlier uh + + align:start position:0% +earlier uh + + + align:start position:0% +earlier uh +anity and grid + + align:start position:0% + + + + align:start position:0% + +graphs but here's now a nice simple + + align:start position:0% +graphs but here's now a nice simple + + + align:start position:0% +graphs but here's now a nice simple +proof using what we + + align:start position:0% +proof using what we + + + align:start position:0% +proof using what we +know uh I'll tell you more reasons uh in + + align:start position:0% +know uh I'll tell you more reasons uh in + + + align:start position:0% +know uh I'll tell you more reasons uh in +a little bit but I have one more at this + + align:start position:0% +a little bit but I have one more at this + + + align:start position:0% +a little bit but I have one more at this +point which is platform + + align:start position:0% + + + + align:start position:0% + +games I don't have a Graphic because + + align:start position:0% +games I don't have a Graphic because + + + align:start position:0% +games I don't have a Graphic because +there there's so many games that could + + align:start position:0% +there there's so many games that could + + + align:start position:0% +there there's so many games that could +apply here uh Super Mario Brothers among + + align:start position:0% +apply here uh Super Mario Brothers among + + + align:start position:0% +apply here uh Super Mario Brothers among +them suppose you have uh a little dude + + align:start position:0% +them suppose you have uh a little dude + + + align:start position:0% +them suppose you have uh a little dude +who can walk around and you've got some + + align:start position:0% +who can walk around and you've got some + + + align:start position:0% +who can walk around and you've got some +kind of coins I don't know how to draw + + align:start position:0% +kind of coins I don't know how to draw + + + align:start position:0% +kind of coins I don't know how to draw +coins those look like eyeballs but + + align:start position:0% +coins those look like eyeballs but + + + align:start position:0% +coins those look like eyeballs but +anyway uh you've got a bunch of coins + + align:start position:0% +anyway uh you've got a bunch of coins + + + align:start position:0% +anyway uh you've got a bunch of coins +which you want to collect and let's say + + align:start position:0% +which you want to collect and let's say + + + align:start position:0% +which you want to collect and let's say +uh and you have some way that you can + + align:start position:0% +uh and you have some way that you can + + + align:start position:0% +uh and you have some way that you can +walk around if you're top down game then + + align:start position:0% +walk around if you're top down game then + + + align:start position:0% +walk around if you're top down game then +that's pretty much the entire reduction + + align:start position:0% +that's pretty much the entire reduction + + + align:start position:0% +that's pretty much the entire reduction +um and then also you have a + + align:start position:0% +um and then also you have a + + + align:start position:0% +um and then also you have a +timer so timer plus + + align:start position:0% + + + + align:start position:0% + +Collectibles bubles or + + align:start position:0% +Collectibles bubles or + + + align:start position:0% +Collectibles bubles or +ibles say ubbles + + align:start position:0% +ibles say ubbles + + + align:start position:0% +ibles say ubbles +um + + align:start position:0% +um + + + align:start position:0% +um +and uh any such game is NP hard at least + + align:start position:0% +and uh any such game is NP hard at least + + + align:start position:0% +and uh any such game is NP hard at least +uh because if you want to get all of + + align:start position:0% +uh because if you want to get all of + + + align:start position:0% +uh because if you want to get all of +these coins that's like vertices you + + align:start position:0% +these coins that's like vertices you + + + align:start position:0% +these coins that's like vertices you +need to visit and if it's say a top down + + align:start position:0% +need to visit and if it's say a top down + + + align:start position:0% +need to visit and if it's say a top down +game you're you're walking in a grid + + align:start position:0% +game you're you're walking in a grid + + + align:start position:0% +game you're you're walking in a grid +graph the time limit will prevent us + + align:start position:0% +graph the time limit will prevent us + + + align:start position:0% +graph the time limit will prevent us +from going out into the Whit space + + align:start position:0% +from going out into the Whit space + + + align:start position:0% +from going out into the Whit space +because there's no coins there and so if + + align:start position:0% +because there's no coins there and so if + + + align:start position:0% +because there's no coins there and so if +the time limit is exactly the number of + + align:start position:0% +the time limit is exactly the number of + + + align:start position:0% +the time limit is exactly the number of +coins in every step you make you have to + + align:start position:0% +coins in every step you make you have to + + + align:start position:0% +coins in every step you make you have to +get a coin then uh that will force you + + align:start position:0% +get a coin then uh that will force you + + + align:start position:0% +get a coin then uh that will force you +to only follow these the edges in the + + align:start position:0% +to only follow these the edges in the + + + align:start position:0% +to only follow these the edges in the +grid graph can't go out + + align:start position:0% +grid graph can't go out + + + align:start position:0% +grid graph can't go out +here no obstacles needed um and you + + align:start position:0% +here no obstacles needed um and you + + + align:start position:0% +here no obstacles needed um and you +understand that in the real game of + + align:start position:0% +understand that in the real game of + + + align:start position:0% +understand that in the real game of +course there might be stuff happening + + align:start position:0% +course there might be stuff happening + + + align:start position:0% +course there might be stuff happening +here you know maybe there's a ladder so + + align:start position:0% +here you know maybe there's a ladder so + + + align:start position:0% +here you know maybe there's a ladder so +you can go up here and it's uh you just + + align:start position:0% +you can go up here and it's uh you just + + + align:start position:0% +you can go up here and it's uh you just +have to set up all of these traversal + + align:start position:0% +have to set up all of these traversal + + + align:start position:0% +have to set up all of these traversal +lengths to take the same amount of time + + align:start position:0% +lengths to take the same amount of time + + + align:start position:0% +lengths to take the same amount of time +in under optimal play and then you can + + align:start position:0% +in under optimal play and then you can + + + align:start position:0% +in under optimal play and then you can +simulate a ton of video games in this + + align:start position:0% +simulate a ton of video games in this + + + align:start position:0% +simulate a ton of video games in this +way okay this is a result this is in fun + + align:start position:0% +way okay this is a result this is in fun + + + align:start position:0% +way okay this is a result this is in fun +2010 by + + align:start position:0% +2010 by + + + align:start position:0% +2010 by +foric okay so some reasons why you care + + align:start position:0% +foric okay so some reasons why you care + + + align:start position:0% +foric okay so some reasons why you care +a lot of games map naturally onto grids + + align:start position:0% +a lot of games map naturally onto grids + + + align:start position:0% +a lot of games map naturally onto grids +uh a lot of real problems map onto can + + align:start position:0% +uh a lot of real problems map onto can + + + align:start position:0% +uh a lot of real problems map onto can +map onto + + align:start position:0% +map onto + + + align:start position:0% +map onto +grids uh but in general grids will be + + align:start position:0% +grids uh but in general grids will be + + + align:start position:0% +grids uh but in general grids will be +very + + align:start position:0% +very + + + align:start position:0% +very +helpful uh so uh next problem I want to + + align:start position:0% +helpful uh so uh next problem I want to + + + align:start position:0% +helpful uh so uh next problem I want to +solve is by solve I mean show hard as + + align:start position:0% +solve is by solve I mean show hard as + + + align:start position:0% +solve is by solve I mean show hard as +usual um let's say + + align:start position:0% +usual um let's say + + + align:start position:0% +usual um let's say +Max + + align:start position:0% +Max + + + align:start position:0% +Max +degree 3 + + align:start position:0% +degree 3 + + + align:start position:0% +degree 3 +grid + + align:start position:0% + + + + align:start position:0% + +graphs I don't have a great motiv well I + + align:start position:0% +graphs I don't have a great motiv well I + + + align:start position:0% +graphs I don't have a great motiv well I +have a motivation for this um there + + align:start position:0% +have a motivation for this um there + + + align:start position:0% +have a motivation for this um there +probably others that I'm not aware of I + + align:start position:0% +probably others that I'm not aware of I + + + align:start position:0% +probably others that I'm not aware of I +hadn't didn't actually know about this + + align:start position:0% +hadn't didn't actually know about this + + + align:start position:0% +hadn't didn't actually know about this +result until recently it's pretty cool + + align:start position:0% +result until recently it's pretty cool + + + align:start position:0% +result until recently it's pretty cool +uh if you look at this reduction there + + align:start position:0% +uh if you look at this reduction there + + + align:start position:0% +uh if you look at this reduction there +are some vertices that I mean here we're + + align:start position:0% +are some vertices that I mean here we're + + + align:start position:0% +are some vertices that I mean here we're +drawing the cycle but some vertices have + + align:start position:0% +drawing the cycle but some vertices have + + + align:start position:0% +drawing the cycle but some vertices have +degree four of course every grid graph + + align:start position:0% +degree four of course every grid graph + + + align:start position:0% +degree four of course every grid graph +is Max degree four uh and Max degree 2 + + align:start position:0% +is Max degree four uh and Max degree 2 + + + align:start position:0% +is Max degree four uh and Max degree 2 +is pretty easy to solve hamiltonicity so + + align:start position:0% +is pretty easy to solve hamiltonicity so + + + align:start position:0% +is pretty easy to solve hamiltonicity so +uh what's left is Max degree 3 so + + align:start position:0% +uh what's left is Max degree 3 so + + + align:start position:0% +uh what's left is Max degree 3 so +natural question in between is can you + + align:start position:0% +natural question in between is can you + + + align:start position:0% +natural question in between is can you +do Max degree 3 grid graphs claim is + + align:start position:0% +do Max degree 3 grid graphs claim is + + + align:start position:0% +do Max degree 3 grid graphs claim is +that is also hard and it's going to be + + align:start position:0% +that is also hard and it's going to be + + + align:start position:0% +that is also hard and it's going to be +basically the same proof but we're going + + align:start position:0% +basically the same proof but we're going + + + align:start position:0% +basically the same proof but we're going +to change all the gadgets well most of + + align:start position:0% +to change all the gadgets well most of + + + align:start position:0% +to change all the gadgets well most of +them uh and so this is by there's one + + align:start position:0% +them uh and so this is by there's one + + + align:start position:0% +them uh and so this is by there's one +shared author this was e Papa Demetrio + + align:start position:0% + + + + align:start position:0% + +Ander um and then this is purion and + + align:start position:0% +Ander um and then this is purion and + + + align:start position:0% +Ander um and then this is purion and +vasani uh a couple years later so uh the + + align:start position:0% +vasani uh a couple years later so uh the + + + align:start position:0% +vasani uh a couple years later so uh the +this is actually very similar to the + + align:start position:0% +this is actually very similar to the + + + align:start position:0% +this is actually very similar to the +edge Gadget we saw before here's the old + + align:start position:0% +edge Gadget we saw before here's the old + + + align:start position:0% +edge Gadget we saw before here's the old +Edge Gadget and the turns see before + + align:start position:0% +Edge Gadget and the turns see before + + + align:start position:0% +Edge Gadget and the turns see before +when we had a turn we had a degree four + + align:start position:0% +when we had a turn we had a degree four + + + align:start position:0% +when we had a turn we had a degree four +vertex I want to get rid of that and I'm + + align:start position:0% +vertex I want to get rid of that and I'm + + + align:start position:0% +vertex I want to get rid of that and I'm +going to get rid of it by just sort of + + align:start position:0% +going to get rid of it by just sort of + + + align:start position:0% +going to get rid of it by just sort of +shifting these things apart and blowing + + align:start position:0% +shifting these things apart and blowing + + + align:start position:0% +shifting these things apart and blowing +up this circle this cycle uh so I end up + + align:start position:0% +up this circle this cycle uh so I end up + + + align:start position:0% +up this circle this cycle uh so I end up +with a bigger cycle here I end up with + + align:start position:0% +with a bigger cycle here I end up with + + + align:start position:0% +with a bigger cycle here I end up with +an edge connection there but effectively + + align:start position:0% +an edge connection there but effectively + + + align:start position:0% +an edge connection there but effectively +it's the same kind of topology um if + + align:start position:0% +it's the same kind of topology um if + + + align:start position:0% +it's the same kind of topology um if +you're coming in and + + align:start position:0% +you're coming in and + + + align:start position:0% +you're coming in and +alternating uh + + align:start position:0% +alternating uh + + + align:start position:0% +alternating uh +uh I guess you have to get the parody + + align:start position:0% +uh I guess you have to get the parody + + + align:start position:0% +uh I guess you have to get the parody +right if you're coming in from this side + + align:start position:0% +right if you're coming in from this side + + + align:start position:0% +right if you're coming in from this side +and you're alternating then you can come + + align:start position:0% +and you're alternating then you can come + + + align:start position:0% +and you're alternating then you can come +around and visit like that and + + align:start position:0% +around and visit like that and + + + align:start position:0% +around and visit like that and +everything is okay back and + + align:start position:0% +everything is okay back and + + + align:start position:0% +everything is okay back and +forth cool that it's drawn right over + + align:start position:0% +forth cool that it's drawn right over + + + align:start position:0% +forth cool that it's drawn right over +here that's the zigzag path the return + + align:start position:0% +here that's the zigzag path the return + + + align:start position:0% +here that's the zigzag path the return +path is just as before and so we can use + + align:start position:0% +path is just as before and so we can use + + + align:start position:0% +path is just as before and so we can use +this Edge Gadget exactly as we did + + align:start position:0% +this Edge Gadget exactly as we did + + + align:start position:0% +this Edge Gadget exactly as we did +before uh but now it's Max degree 3 + + align:start position:0% +before uh but now it's Max degree 3 + + + align:start position:0% +before uh but now it's Max degree 3 +everywhere so that's easy in general + + align:start position:0% +everywhere so that's easy in general + + + align:start position:0% +everywhere so that's easy in general +using this trick that if we have uh here + + align:start position:0% +using this trick that if we have uh here + + + align:start position:0% +using this trick that if we have uh here +we had a corner uh with a vertex on it + + align:start position:0% +we had a corner uh with a vertex on it + + + align:start position:0% +we had a corner uh with a vertex on it +you can turn that into a longer path + + align:start position:0% +you can turn that into a longer path + + + align:start position:0% +you can turn that into a longer path +with various vertices on it that will + + align:start position:0% +with various vertices on it that will + + + align:start position:0% +with various vertices on it that will +act the same from a hamiltonicity + + align:start position:0% +act the same from a hamiltonicity + + + align:start position:0% +act the same from a hamiltonicity +perspective so that's the key thing + + align:start position:0% +perspective so that's the key thing + + + align:start position:0% +perspective so that's the key thing +we're doing and then uh then we're just + + align:start position:0% +we're doing and then uh then we're just + + + align:start position:0% +we're doing and then uh then we're just +it's a matter of putting things to fit + + align:start position:0% +it's a matter of putting things to fit + + + align:start position:0% +it's a matter of putting things to fit +on the + + align:start position:0% +on the + + + align:start position:0% +on the +grid okay so that's first change now the + + align:start position:0% +grid okay so that's first change now the + + + align:start position:0% +grid okay so that's first change now the +second change is going to be a little + + align:start position:0% +second change is going to be a little + + + align:start position:0% +second change is going to be a little +bit more drastic a little weirder uh the + + align:start position:0% +bit more drastic a little weirder uh the + + + align:start position:0% +bit more drastic a little weirder uh the +vertex Gadget used to be this 3x3 thing + + align:start position:0% +vertex Gadget used to be this 3x3 thing + + + align:start position:0% +vertex Gadget used to be this 3x3 thing +very hard to get rid of that vertex of + + align:start position:0% +very hard to get rid of that vertex of + + + align:start position:0% +very hard to get rid of that vertex of +degree 4 in the center uh well if you + + align:start position:0% +degree 4 in the center uh well if you + + + align:start position:0% +degree 4 in the center uh well if you +did that you would be left with a little + + align:start position:0% +did that you would be left with a little + + + align:start position:0% +did that you would be left with a little +square an empty square and uh we're + + align:start position:0% +square an empty square and uh we're + + + align:start position:0% +square an empty square and uh we're +going to need two of those so this is + + align:start position:0% +going to need two of those so this is + + + align:start position:0% +going to need two of those so this is +the dumbbell picture used in many + + align:start position:0% +the dumbbell picture used in many + + + align:start position:0% +the dumbbell picture used in many +theoretical results so we have uh two of + + align:start position:0% +theoretical results so we have uh two of + + + align:start position:0% +theoretical results so we have uh two of +these ver these squares we're going to + + align:start position:0% +these ver these squares we're going to + + + align:start position:0% +these ver these squares we're going to +separate them by a fairly long path of + + align:start position:0% +separate them by a fairly long path of + + + align:start position:0% +separate them by a fairly long path of +the right + + align:start position:0% +the right + + + align:start position:0% +the right +par and the idea is uh you can have up + + align:start position:0% +par and the idea is uh you can have up + + + align:start position:0% +par and the idea is uh you can have up +to two connections over here to edges + + align:start position:0% +to two connections over here to edges + + + align:start position:0% +to two connections over here to edges +and up to two connections over here for + + align:start position:0% +and up to two connections over here for + + + align:start position:0% +and up to two connections over here for +edges and here's a typical connections + + align:start position:0% +edges and here's a typical connections + + + align:start position:0% +edges and here's a typical connections +are going to look just like we had + + align:start position:0% +are going to look just like we had + + + align:start position:0% +are going to look just like we had +before um but it's not going to quite + + align:start position:0% +before um but it's not going to quite + + + align:start position:0% +before um but it's not going to quite +all be like this so it used to be we + + align:start position:0% +all be like this so it used to be we + + + align:start position:0% +all be like this so it used to be we +could have a full Edge connection or we + + align:start position:0% +could have a full Edge connection or we + + + align:start position:0% +could have a full Edge connection or we +can have a pin + + align:start position:0% +can have a pin + + + align:start position:0% +can have a pin +connection as before uh it's just the + + align:start position:0% +connection as before uh it's just the + + + align:start position:0% +connection as before uh it's just the +when this Edge turns it's going to use + + align:start position:0% +when this Edge turns it's going to use + + + align:start position:0% +when this Edge turns it's going to use +the weirder turn Gadget so we just the + + align:start position:0% +the weirder turn Gadget so we just the + + + align:start position:0% +the weirder turn Gadget so we just the +the the edges look basically the same as + + align:start position:0% +the the edges look basically the same as + + + align:start position:0% +the the edges look basically the same as +just the turns that we changed in the + + align:start position:0% +just the turns that we changed in the + + + align:start position:0% +just the turns that we changed in the +last + + align:start position:0% +last + + + align:start position:0% +last +slide okay uh this almost Works uh but I + + align:start position:0% +slide okay uh this almost Works uh but I + + + align:start position:0% +slide okay uh this almost Works uh but I +have to specify some details + + align:start position:0% +have to specify some details + + + align:start position:0% +have to specify some details +so for example uh let's easy case degree + + align:start position:0% +so for example uh let's easy case degree + + + align:start position:0% +so for example uh let's easy case degree +2 vertex suppose the original graph has + + align:start position:0% +2 vertex suppose the original graph has + + + align:start position:0% +2 vertex suppose the original graph has +a degree 2 vertex we had that in our + + align:start position:0% +a degree 2 vertex we had that in our + + + align:start position:0% +a degree 2 vertex we had that in our +reductions uh because in fact every + + align:start position:0% +reductions uh because in fact every + + + align:start position:0% +reductions uh because in fact every +other vertex pretty much was degree 2 + + align:start position:0% +other vertex pretty much was degree 2 + + + align:start position:0% +other vertex pretty much was degree 2 +when if you track all of these things uh + + align:start position:0% +when if you track all of these things uh + + + align:start position:0% +when if you track all of these things uh +when we went from the directed case to + + align:start position:0% +when we went from the directed case to + + + align:start position:0% +when we went from the directed case to +the bipartite case we added in lots of + + align:start position:0% +the bipartite case we added in lots of + + + align:start position:0% +the bipartite case we added in lots of +vertices lots of degree 2 vertices so if + + align:start position:0% +vertices lots of degree 2 vertices so if + + + align:start position:0% +vertices lots of degree 2 vertices so if +we want to simulate a degree 2 vertex uh + + align:start position:0% +we want to simulate a degree 2 vertex uh + + + align:start position:0% +we want to simulate a degree 2 vertex uh +we will just have one of the edges + + align:start position:0% +we will just have one of the edges + + + align:start position:0% +we will just have one of the edges +attaching up here and one of the edges + + align:start position:0% +attaching up here and one of the edges + + + align:start position:0% +attaching up here and one of the edges +attaching down here and again up in this + + align:start position:0% +attaching down here and again up in this + + + align:start position:0% +attaching down here and again up in this +in this picture it's one on the left + + align:start position:0% +in this picture it's one on the left + + + align:start position:0% +in this picture it's one on the left +side one on the right side and again we + + align:start position:0% +side one on the right side and again we + + + align:start position:0% +side one on the right side and again we +have this feature that if we start at + + align:start position:0% +have this feature that if we start at + + + align:start position:0% +have this feature that if we start at +any of the pis we can get to uh one of + + align:start position:0% +any of the pis we can get to uh one of + + + align:start position:0% +any of the pis we can get to uh one of +the PJs by visiting all the uh EI + + align:start position:0% +the PJs by visiting all the uh EI + + + align:start position:0% +the PJs by visiting all the uh EI +edges okay so for example if we start + + align:start position:0% +edges okay so for example if we start + + + align:start position:0% +edges okay so for example if we start +here we go like this over here and we + + align:start position:0% +here we go like this over here and we + + + align:start position:0% +here we go like this over here and we +have a choice we can either go like this + + align:start position:0% +have a choice we can either go like this + + + align:start position:0% +have a choice we can either go like this +and end It P3 or go like this and end it + + align:start position:0% +and end It P3 or go like this and end it + + + align:start position:0% +and end It P3 or go like this and end it +P4 we visited all the + + align:start position:0% +P4 we visited all the + + + align:start position:0% +P4 we visited all the +e but we can't start at P1 and end at P2 + + align:start position:0% +e but we can't start at P1 and end at P2 + + + align:start position:0% +e but we can't start at P1 and end at P2 +if we want to visit everything right + + align:start position:0% +if we want to visit everything right + + + align:start position:0% +if we want to visit everything right +start at P1 if you go out there you're + + align:start position:0% +start at P1 if you go out there you're + + + align:start position:0% +start at P1 if you go out there you're +you can never come back if you come + + align:start position:0% +you can never come back if you come + + + align:start position:0% +you can never come back if you come +around here you've already visited P2 so + + align:start position:0% +around here you've already visited P2 so + + + align:start position:0% +around here you've already visited P2 so +we cannot start an end on the left side + + align:start position:0% +we cannot start an end on the left side + + + align:start position:0% +we cannot start an end on the left side +we cannot start an end on the right side + + align:start position:0% +we cannot start an end on the right side + + + align:start position:0% +we cannot start an end on the right side +so for a degree 2 vertex that's fine we + + align:start position:0% +so for a degree 2 vertex that's fine we + + + align:start position:0% +so for a degree 2 vertex that's fine we +just put one of the connections on one + + align:start position:0% +just put one of the connections on one + + + align:start position:0% +just put one of the connections on one +side one on the other and you know we'll + + align:start position:0% +side one on the other and you know we'll + + + align:start position:0% +side one on the other and you know we'll +come in visit everything come out and + + align:start position:0% +come in visit everything come out and + + + align:start position:0% +come in visit everything come out and +because we visit all the Eis we can do + + align:start position:0% +because we visit all the Eis we can do + + + align:start position:0% +because we visit all the Eis we can do +this kind of uh traversal every time + + align:start position:0% +this kind of uh traversal every time + + + align:start position:0% +this kind of uh traversal every time +now for degree 3 vertex this is a little + + align:start position:0% +now for degree 3 vertex this is a little + + + align:start position:0% +now for degree 3 vertex this is a little +bit Troublesome um + + align:start position:0% + + + + align:start position:0% + +remember our + + align:start position:0% + + + + align:start position:0% + +picture uh What do degree through + + align:start position:0% +picture uh What do degree through + + + align:start position:0% +picture uh What do degree through +vertices look like if you follow through + + align:start position:0% +vertices look like if you follow through + + + align:start position:0% +vertices look like if you follow through +the chain of reductions we had this case + + align:start position:0% +the chain of reductions we had this case + + + align:start position:0% +the chain of reductions we had this case +and we + + align:start position:0% +and we + + + align:start position:0% +and we +had this case and this one we converted + + align:start position:0% +had this case and this one we converted + + + align:start position:0% +had this case and this one we converted +into + + align:start position:0% +into + + + align:start position:0% +into +that and this one we converted + + align:start position:0% + + + + align:start position:0% + +into that I + + align:start position:0% +into that I + + + align:start position:0% +into that I +think y uh because this was a forced + + align:start position:0% +think y uh because this was a forced + + + align:start position:0% +think y uh because this was a forced +Edge this was a forced Edge and so we + + align:start position:0% +Edge this was a forced Edge and so we + + + align:start position:0% +Edge this was a forced Edge and so we +added a DOT to represent that so good + + align:start position:0% +added a DOT to represent that so good + + + align:start position:0% +added a DOT to represent that so good +news is every time we have a degree 3 + + align:start position:0% +news is every time we have a degree 3 + + + align:start position:0% +news is every time we have a degree 3 +vertex in this uh in the starting graph + + align:start position:0% +vertex in this uh in the starting graph + + + align:start position:0% +vertex in this uh in the starting graph +one of the edges is forced one of the + + align:start position:0% +one of the edges is forced one of the + + + align:start position:0% +one of the edges is forced one of the +three edges is forced so it's really a + + align:start position:0% +three edges is forced so it's really a + + + align:start position:0% +three edges is forced so it's really a +choice between do you take this one or + + align:start position:0% +choice between do you take this one or + + + align:start position:0% +choice between do you take this one or +do you take this one I mean that's of + + align:start position:0% +do you take this one I mean that's of + + + align:start position:0% +do you take this one I mean that's of +course what we had over + + align:start position:0% +course what we had over + + + align:start position:0% +course what we had over +here so what we're going to do is take + + align:start position:0% +here so what we're going to do is take + + + align:start position:0% +here so what we're going to do is take +these two edges which are exclusively + + align:start position:0% +these two edges which are exclusively + + + align:start position:0% +these two edges which are exclusively +ored together right I choose exactly one + + align:start position:0% +ored together right I choose exactly one + + + align:start position:0% +ored together right I choose exactly one +of these uh we're going to put that on + + align:start position:0% +of these uh we're going to put that on + + + align:start position:0% +of these uh we're going to put that on +one side so that one of them will go up + + align:start position:0% +one side so that one of them will go up + + + align:start position:0% +one side so that one of them will go up +here one of them will go down + + align:start position:0% +here one of them will go down + + + align:start position:0% +here one of them will go down +here and then the forced Edge we'll put + + align:start position:0% +here and then the forced Edge we'll put + + + align:start position:0% +here and then the forced Edge we'll put +over on the other side forc edge is + + align:start position:0% +over on the other side forc edge is + + + align:start position:0% +over on the other side forc edge is +always chosen so that means we'll come + + align:start position:0% +always chosen so that means we'll come + + + align:start position:0% +always chosen so that means we'll come +in on either P1 or P2 or leave on P1 or + + align:start position:0% +in on either P1 or P2 or leave on P1 or + + + align:start position:0% +in on either P1 or P2 or leave on P1 or +P2 depending on which of those two cases + + align:start position:0% +P2 depending on which of those two cases + + + align:start position:0% +P2 depending on which of those two cases +we're in and then uh we will leave or + + align:start position:0% +we're in and then uh we will leave or + + + align:start position:0% +we're in and then uh we will leave or +enter from P3 or P4 According to which + + align:start position:0% +enter from P3 or P4 According to which + + + align:start position:0% +enter from P3 or P4 According to which +of the two edges you + + align:start position:0% +of the two edges you + + + align:start position:0% +of the two edges you +choose happy no I'm understanding that + + align:start position:0% +choose happy no I'm understanding that + + + align:start position:0% +choose happy no I'm understanding that +we're actually reducing from a sub + + align:start position:0% +we're actually reducing from a sub + + + align:start position:0% +we're actually reducing from a sub +problem with cleanar bipar x 33 graphs + + align:start position:0% +problem with cleanar bipar x 33 graphs + + + align:start position:0% +problem with cleanar bipar x 33 graphs +in that every vertex is connected to at + + align:start position:0% +in that every vertex is connected to at + + + align:start position:0% +in that every vertex is connected to at +least one degre 2 + + align:start position:0% +least one degre 2 + + + align:start position:0% +least one degre 2 +vertex yeah uh + + align:start position:0% +vertex yeah uh + + + align:start position:0% +vertex yeah uh +right so we could say at this point in + + align:start position:0% +right so we could say at this point in + + + align:start position:0% +right so we could say at this point in +fact it's planer by partite Max degree 3 + + align:start position:0% +fact it's planer by partite Max degree 3 + + + align:start position:0% +fact it's planer by partite Max degree 3 +graphs where every degree 3 vertex is + + align:start position:0% +graphs where every degree 3 vertex is + + + align:start position:0% +graphs where every degree 3 vertex is +adjacent to at least to exactly one or + + align:start position:0% +adjacent to at least to exactly one or + + + align:start position:0% +adjacent to at least to exactly one or +no at least one degree 2 vertex uh and + + align:start position:0% +no at least one degree 2 vertex uh and + + + align:start position:0% +no at least one degree 2 vertex uh and +then we can carry that condition through + + align:start position:0% +then we can carry that condition through + + + align:start position:0% +then we can carry that condition through +all the reductions and that would make + + align:start position:0% +all the reductions and that would make + + + align:start position:0% +all the reductions and that would make +this an actual reduction or you can + + align:start position:0% +this an actual reduction or you can + + + align:start position:0% +this an actual reduction or you can +think of this as a reduction going from + + align:start position:0% +think of this as a reduction going from + + + align:start position:0% +think of this as a reduction going from +here just copying all the details yeah + + align:start position:0% + + + + align:start position:0% + +other + + align:start position:0% + + + + align:start position:0% + +questions okay uh I'm a little confused + + align:start position:0% +questions okay uh I'm a little confused + + + align:start position:0% +questions okay uh I'm a little confused +because there's one more Gadget but I + + align:start position:0% +because there's one more Gadget but I + + + align:start position:0% +because there's one more Gadget but I +didn't seem to use that Gadget so um + + align:start position:0% +didn't seem to use that Gadget so um + + + align:start position:0% +didn't seem to use that Gadget so um +this is a so I'm not not sure whether + + align:start position:0% +this is a so I'm not not sure whether + + + align:start position:0% +this is a so I'm not not sure whether +this is necessary uh but here's another + + align:start position:0% +this is necessary uh but here's another + + + align:start position:0% +this is necessary uh but here's another +thing you can do uh which they were + + align:start position:0% +thing you can do uh which they were + + + align:start position:0% +thing you can do uh which they were +using for the forced edges you can have + + align:start position:0% +using for the forced edges you can have + + + align:start position:0% +using for the forced edges you can have +one wire uh sorry this is the picture + + align:start position:0% +one wire uh sorry this is the picture + + + align:start position:0% +one wire uh sorry this is the picture +you can have one Edge Gadget that + + align:start position:0% +you can have one Edge Gadget that + + + align:start position:0% +you can have one Edge Gadget that +attaches to both ends of the dumbbell so + + align:start position:0% +attaches to both ends of the dumbbell so + + + align:start position:0% +attaches to both ends of the dumbbell so +then you have a choice whether you end + + align:start position:0% +then you have a choice whether you end + + + align:start position:0% +then you have a choice whether you end +up connecting that edge to the bottom of + + align:start position:0% +up connecting that edge to the bottom of + + + align:start position:0% +up connecting that edge to the bottom of +the dumbbell or to the top of the + + align:start position:0% +the dumbbell or to the top of the + + + align:start position:0% +the dumbbell or to the top of the +dumbbell uh sorry this is connecting to + + align:start position:0% +dumbbell uh sorry this is connecting to + + + align:start position:0% +dumbbell uh sorry this is connecting to +the top and this is connecting to the + + align:start position:0% +the top and this is connecting to the + + + align:start position:0% +the top and this is connecting to the +bottom the dumbbell so that's another + + align:start position:0% +bottom the dumbbell so that's another + + + align:start position:0% +bottom the dumbbell so that's another +way to do the same kind of degree 3 + + align:start position:0% +way to do the same kind of degree 3 + + + align:start position:0% +way to do the same kind of degree 3 +vertex you could have uh this guy coming + + align:start position:0% +vertex you could have uh this guy coming + + + align:start position:0% +vertex you could have uh this guy coming +in this is the forced Edge so and the + + align:start position:0% +in this is the forced Edge so and the + + + align:start position:0% +in this is the forced Edge so and the +forc edge has to come to this vertex uh + + align:start position:0% +forc edge has to come to this vertex uh + + + align:start position:0% +forc edge has to come to this vertex uh +you get a Cho so whether you start up + + align:start position:0% +you get a Cho so whether you start up + + + align:start position:0% +you get a Cho so whether you start up +here and then leave along this nonforced + + align:start position:0% +here and then leave along this nonforced + + + align:start position:0% +here and then leave along this nonforced +Edge or you first Traverse down this way + + align:start position:0% +Edge or you first Traverse down this way + + + align:start position:0% +Edge or you first Traverse down this way +and then leave along this nonforced + + align:start position:0% +and then leave along this nonforced + + + align:start position:0% +and then leave along this nonforced +Edge so that's another way to do it but + + align:start position:0% +Edge so that's another way to do it but + + + align:start position:0% +Edge so that's another way to do it but +I it seems just as good as the way I + + align:start position:0% +I it seems just as good as the way I + + + align:start position:0% +I it seems just as good as the way I +described which was to put forced Edge + + align:start position:0% +described which was to put forced Edge + + + align:start position:0% +described which was to put forced Edge +only on one side and then the other two + + align:start position:0% +only on one side and then the other two + + + align:start position:0% +only on one side and then the other two +guys on the other side unless there's a + + align:start position:0% +guys on the other side unless there's a + + + align:start position:0% +guys on the other side unless there's a +par issue it could be that the you know + + align:start position:0% +par issue it could be that the you know + + + align:start position:0% +par issue it could be that the you know +this connection and this connection uh + + align:start position:0% +this connection and this connection uh + + + align:start position:0% +this connection and this connection uh +have the opposite opposite + + align:start position:0% +have the opposite opposite + + + align:start position:0% +have the opposite opposite +parities which is not good because we + + align:start position:0% +parities which is not good because we + + + align:start position:0% +parities which is not good because we +want the two + + align:start position:0% +want the two + + + align:start position:0% +want the two +connections um uh in this case both of + + align:start position:0% +connections um uh in this case both of + + + align:start position:0% +connections um uh in this case both of +these are going to be + + align:start position:0% +these are going to be + + + align:start position:0% +these are going to be +white and in this case both of these are + + align:start position:0% +white and in this case both of these are + + + align:start position:0% +white and in this case both of these are +going to be black so the two non-forced + + align:start position:0% +going to be black so the two non-forced + + + align:start position:0% +going to be black so the two non-forced +edges connect to vertices of the same + + align:start position:0% +edges connect to vertices of the same + + + align:start position:0% +edges connect to vertices of the same +color and I think if you try to attach + + align:start position:0% +color and I think if you try to attach + + + align:start position:0% +color and I think if you try to attach +one of them over here and one of them + + align:start position:0% +one of them over here and one of them + + + align:start position:0% +one of them over here and one of them +over here on a variable they will have + + align:start position:0% +over here on a variable they will have + + + align:start position:0% +over here on a variable they will have +the wrong colors they have opposite + + align:start position:0% +the wrong colors they have opposite + + + align:start position:0% +the wrong colors they have opposite +colors I think that's why you need this + + align:start position:0% +colors I think that's why you need this + + + align:start position:0% +colors I think that's why you need this +gadget CU now the this left connection + + align:start position:0% +gadget CU now the this left connection + + + align:start position:0% +gadget CU now the this left connection +and this other left connection will have + + align:start position:0% +and this other left connection will have + + + align:start position:0% +and this other left connection will have +the same par because this count is odd I + + align:start position:0% +the same par because this count is odd I + + + align:start position:0% +the same par because this count is odd I +think so I think that's why you need it + + align:start position:0% +think so I think that's why you need it + + + align:start position:0% +think so I think that's why you need it +and that preserves parity so it's a bit + + align:start position:0% +and that preserves parity so it's a bit + + + align:start position:0% +and that preserves parity so it's a bit +subtle you have to be careful all the + + align:start position:0% +subtle you have to be careful all the + + + align:start position:0% +subtle you have to be careful all the +connections preserve + + align:start position:0% +connections preserve + + + align:start position:0% +connections preserve +parity + + align:start position:0% +parity + + + align:start position:0% +parity +cool so that was Max degree 3 grid + + align:start position:0% +cool so that was Max degree 3 grid + + + align:start position:0% +cool so that was Max degree 3 grid +graphs any other + + align:start position:0% + + + + align:start position:0% + +questions um here is one one motivation + + align:start position:0% +questions um here is one one motivation + + + align:start position:0% +questions um here is one one motivation +that's from this Papa Demetri vasani + + align:start position:0% +that's from this Papa Demetri vasani + + + align:start position:0% +that's from this Papa Demetri vasani +paper for this + + align:start position:0% + + + + align:start position:0% + +problem related to ukian traveling + + align:start position:0% +problem related to ukian traveling + + + align:start position:0% +problem related to ukian traveling +salesman problem + + align:start position:0% + + + + align:start position:0% + +is this notion of degree bounded minimum + + align:start position:0% +is this notion of degree bounded minimum + + + align:start position:0% +is this notion of degree bounded minimum +spanning tree minimum spanning tree + + align:start position:0% +spanning tree minimum spanning tree + + + align:start position:0% +spanning tree minimum spanning tree +normally is a polinomial problem where + + align:start position:0% +normally is a polinomial problem where + + + align:start position:0% +normally is a polinomial problem where +you're given some graph you want to find + + align:start position:0% +you're given some graph you want to find + + + align:start position:0% +you're given some graph you want to find +a spanning tree you know tree that + + align:start position:0% +a spanning tree you know tree that + + + align:start position:0% +a spanning tree you know tree that +visits all the the vertices but it can + + align:start position:0% +visits all the the vertices but it can + + + align:start position:0% +visits all the the vertices but it can +be uh a tree instead of just a path and + + align:start position:0% +be uh a tree instead of just a path and + + + align:start position:0% +be uh a tree instead of just a path and +it's minimum and that it has minimum + + align:start position:0% +it's minimum and that it has minimum + + + align:start position:0% +it's minimum and that it has minimum +total length of all the edges so that's + + align:start position:0% +total length of all the edges so that's + + + align:start position:0% +total length of all the edges so that's +a polinomial problem uh if I say well I + + align:start position:0% +a polinomial problem uh if I say well I + + + align:start position:0% +a polinomial problem uh if I say well I +want a minimum spanning tree where all + + align:start position:0% +want a minimum spanning tree where all + + + align:start position:0% +want a minimum spanning tree where all +of the uh vertices in the tree have Max + + align:start position:0% +of the uh vertices in the tree have Max + + + align:start position:0% +of the uh vertices in the tree have Max +degree two that is hamiltonian path or I + + align:start position:0% +degree two that is hamiltonian path or I + + + align:start position:0% +degree two that is hamiltonian path or I +guess really traveling salesman problem + + align:start position:0% +guess really traveling salesman problem + + + align:start position:0% +guess really traveling salesman problem +so we already proved uh ukian Max degree + + align:start position:0% +so we already proved uh ukian Max degree + + + align:start position:0% +so we already proved uh ukian Max degree +2 uh minimum spanning tree is hard what + + align:start position:0% +2 uh minimum spanning tree is hard what + + + align:start position:0% +2 uh minimum spanning tree is hard what +about Max degree 3 does that somehow + + align:start position:0% +about Max degree 3 does that somehow + + + align:start position:0% +about Max degree 3 does that somehow +does the branching make it easier and + + align:start position:0% +does the branching make it easier and + + + align:start position:0% +does the branching make it easier and +the answer is no you start from this + + align:start position:0% +the answer is no you start from this + + + align:start position:0% +the answer is no you start from this +problem and the cool thing about a Max + + align:start position:0% +problem and the cool thing about a Max + + + align:start position:0% +problem and the cool thing about a Max +degree 3 grid graph is if you look at + + align:start position:0% +degree 3 grid graph is if you look at + + + align:start position:0% +degree 3 grid graph is if you look at +any point + + align:start position:0% +any point + + + align:start position:0% +any point +at most three of its neighboring uh + + align:start position:0% +at most three of its neighboring uh + + + align:start position:0% +at most three of its neighboring uh +spots are actual vertices one of them + + align:start position:0% +spots are actual vertices one of them + + + align:start position:0% +spots are actual vertices one of them +has to be absent in Max degree 3 so what + + align:start position:0% +has to be absent in Max degree 3 so what + + + align:start position:0% +has to be absent in Max degree 3 so what +I'm going to do is add a point really + + align:start position:0% +I'm going to do is add a point really + + + align:start position:0% +I'm going to do is add a point really +close to that + + align:start position:0% +close to that + + + align:start position:0% +close to that +one and now uh you can show in any + + align:start position:0% +one and now uh you can show in any + + + align:start position:0% +one and now uh you can show in any +minimum spaning tree these guys must be + + align:start position:0% +minimum spaning tree these guys must be + + + align:start position:0% +minimum spaning tree these guys must be +connected and uh this one basically has + + align:start position:0% +connected and uh this one basically has + + + align:start position:0% +connected and uh this one basically has +to be a leaf because everything else is + + align:start position:0% +to be a leaf because everything else is + + + align:start position:0% +to be a leaf because everything else is +quite far away I mean at at most you + + align:start position:0% +quite far away I mean at at most you + + + align:start position:0% +quite far away I mean at at most you +have have these guys + + align:start position:0% +have have these guys + + + align:start position:0% +have have these guys +occupied you know that this is + + align:start position:0% +occupied you know that this is + + + align:start position:0% +occupied you know that this is +completely absent so I add this point + + align:start position:0% +completely absent so I add this point + + + align:start position:0% +completely absent so I add this point +I'm going to have to connect this uh it + + align:start position:0% +I'm going to have to connect this uh it + + + align:start position:0% +I'm going to have to connect this uh it +won't be able to connect any other way + + align:start position:0% +won't be able to connect any other way + + + align:start position:0% +won't be able to connect any other way +if I'm if I'm using the shortest + + align:start position:0% +if I'm if I'm using the shortest + + + align:start position:0% +if I'm if I'm using the shortest +possible length and so at that point you + + align:start position:0% +possible length and so at that point you + + + align:start position:0% +possible length and so at that point you +know if this has degree three there's + + align:start position:0% +know if this has degree three there's + + + align:start position:0% +know if this has degree three there's +only two uh incident edges left and so + + align:start position:0% +only two uh incident edges left and so + + + align:start position:0% +only two uh incident edges left and so +it's hamiltonian path again in the grid + + align:start position:0% +it's hamiltonian path again in the grid + + + align:start position:0% +it's hamiltonian path again in the grid +graph so this is why they were motivated + + align:start position:0% +graph so this is why they were motivated + + + align:start position:0% +graph so this is why they were motivated +uh to Define Max degree 3 grid graphs + + align:start position:0% +uh to Define Max degree 3 grid graphs + + + align:start position:0% +uh to Define Max degree 3 grid graphs +and prove that hard + + align:start position:0% + + + + align:start position:0% + +cool some more + + align:start position:0% +cool some more + + + align:start position:0% +cool some more +geometry all right uh so for a long time + + align:start position:0% +geometry all right uh so for a long time + + + align:start position:0% +geometry all right uh so for a long time +you know this is all done in the 80s all + + align:start position:0% +you know this is all done in the 80s all + + + align:start position:0% +you know this is all done in the 80s all +the grid graph stuff uh we only had + + align:start position:0% +the grid graph stuff uh we only had + + + align:start position:0% +the grid graph stuff uh we only had +Square + + align:start position:0% +Square + + + align:start position:0% +Square +grids uh we couldn't afford triangles + + align:start position:0% +grids uh we couldn't afford triangles + + + align:start position:0% +grids uh we couldn't afford triangles +back in the day so uh but recently uh + + align:start position:0% +back in the day so uh but recently uh + + + align:start position:0% +back in the day so uh but recently uh +people started to think about triangular + + align:start position:0% +people started to think about triangular + + + align:start position:0% +people started to think about triangular +grids and hex grids those are the only + + align:start position:0% +grids and hex grids those are the only + + + align:start position:0% +grids and hex grids those are the only +tiling regular Eng gon uh so you can + + align:start position:0% +tiling regular Eng gon uh so you can + + + align:start position:0% +tiling regular Eng gon uh so you can +Define the same kind of thing a + + align:start position:0% +Define the same kind of thing a + + + align:start position:0% +Define the same kind of thing a +triangular grid graph a hexagonal grid + + align:start position:0% +triangular grid graph a hexagonal grid + + + align:start position:0% +triangular grid graph a hexagonal grid +graph again you take a set of points in + + align:start position:0% +graph again you take a set of points in + + + align:start position:0% +graph again you take a set of points in +the Triangular lattice or the hex + + align:start position:0% +the Triangular lattice or the hex + + + align:start position:0% +the Triangular lattice or the hex +lattice is the hex actually a lattice + + align:start position:0% +lattice is the hex actually a lattice + + + align:start position:0% +lattice is the hex actually a lattice +well anyway you know what I mean the hex + + align:start position:0% +well anyway you know what I mean the hex + + + align:start position:0% +well anyway you know what I mean the hex +grid um and you um connect any two + + align:start position:0% +grid um and you um connect any two + + + align:start position:0% +grid um and you um connect any two +points when they're unit distance + + align:start position:0% +points when they're unit distance + + + align:start position:0% +points when they're unit distance +apart where that's defined to be one and + + align:start position:0% +apart where that's defined to be one and + + + align:start position:0% +apart where that's defined to be one and +one okay so again we have the notion of + + align:start position:0% +one okay so again we have the notion of + + + align:start position:0% +one okay so again we have the notion of +solid triangular or hex good graphs when + + align:start position:0% +solid triangular or hex good graphs when + + + align:start position:0% +solid triangular or hex good graphs when +there are no holes again we can + + align:start position:0% +there are no holes again we can + + + align:start position:0% +there are no holes again we can +characterize the pixels they're not + + align:start position:0% +characterize the pixels they're not + + + align:start position:0% +characterize the pixels they're not +really pixel hexel and trickles I don't + + align:start position:0% +really pixel hexel and trickles I don't + + + align:start position:0% +really pixel hexel and trickles I don't +know in the paper they're all just + + align:start position:0% +know in the paper they're all just + + + align:start position:0% +know in the paper they're all just +called pixels there's those types of + + align:start position:0% +called pixels there's those types of + + + align:start position:0% +called pixels there's those types of +faces there's the outside face and then + + align:start position:0% +faces there's the outside face and then + + + align:start position:0% +faces there's the outside face and then +there's the whole + + align:start position:0% +there's the whole + + + align:start position:0% +there's the whole +faces h o e not w h o e okay uh cool um + + align:start position:0% +faces h o e not w h o e okay uh cool um + + + align:start position:0% +faces h o e not w h o e okay uh cool um +they they Define some other terms which + + align:start position:0% +they they Define some other terms which + + + align:start position:0% +they they Define some other terms which +I will get + + align:start position:0% + + + + align:start position:0% + +to let me tell you what's known about + + align:start position:0% +to let me tell you what's known about + + + align:start position:0% +to let me tell you what's known about +out all of these + + align:start position:0% + + + + align:start position:0% + +problems so first thing so these + + align:start position:0% + + + + align:start position:0% + +are other grid graphs + + align:start position:0% + + + + align:start position:0% + +so uh first thing that's known is that + + align:start position:0% +so uh first thing that's known is that + + + align:start position:0% +so uh first thing that's known is that +if you have a solid grid graph + + align:start position:0% +if you have a solid grid graph + + + align:start position:0% +if you have a solid grid graph +uh then the Triangular case is also + + align:start position:0% +uh then the Triangular case is also + + + align:start position:0% +uh then the Triangular case is also +polom so I mentioned solid Square grid + + align:start position:0% +polom so I mentioned solid Square grid + + + align:start position:0% +polom so I mentioned solid Square grid +graphs are easy to solve hamiltonicity + + align:start position:0% +graphs are easy to solve hamiltonicity + + + align:start position:0% +graphs are easy to solve hamiltonicity +in turns out solid triangular grid + + align:start position:0% +in turns out solid triangular grid + + + align:start position:0% +in turns out solid triangular grid +graphs are also easy to solve uh grid + + align:start position:0% +graphs are also easy to solve uh grid + + + align:start position:0% +graphs are also easy to solve uh grid +graphs solve hamiltonicity in almost all + + align:start position:0% +graphs solve hamiltonicity in almost all + + + align:start position:0% +graphs solve hamiltonicity in almost all +of them are hamiltonian certain sense as + + align:start position:0% +of them are hamiltonian certain sense as + + + align:start position:0% +of them are hamiltonian certain sense as +long as you check for some basic things + + align:start position:0% +long as you check for some basic things + + + align:start position:0% +long as you check for some basic things +you shouldn't have uh but hex is + + align:start position:0% +you shouldn't have uh but hex is + + + align:start position:0% +you shouldn't have uh but hex is +open so there's actually a ton of nice + + align:start position:0% +open so there's actually a ton of nice + + + align:start position:0% +open so there's actually a ton of nice +open problem + + align:start position:0% +open problem + + + align:start position:0% +open problem +still uh next + + align:start position:0% + + + + align:start position:0% + +case is called super thin + + align:start position:0% + + + + align:start position:0% + +so what is super thin um super thin + + align:start position:0% +so what is super thin um super thin + + + align:start position:0% +so what is super thin um super thin +means uh there are no + + align:start position:0% +means uh there are no + + + align:start position:0% +means uh there are no +pixels every face is either a hole or + + align:start position:0% +pixels every face is either a hole or + + + align:start position:0% +pixels every face is either a hole or +the outside face okay I don't have an + + align:start position:0% +the outside face okay I don't have an + + + align:start position:0% +the outside face okay I don't have an +example here but this kind of connection + + align:start position:0% +example here but this kind of connection + + + align:start position:0% +example here but this kind of connection +is what you would have in super thin + + align:start position:0% +is what you would have in super thin + + + align:start position:0% +is what you would have in super thin +graphs so you've got uh a whole face + + align:start position:0% +graphs so you've got uh a whole face + + + align:start position:0% +graphs so you've got uh a whole face +here A whole face there uh you shouldn't + + align:start position:0% +here A whole face there uh you shouldn't + + + align:start position:0% +here A whole face there uh you shouldn't +have any of these pixels to be super + + align:start position:0% +have any of these pixels to be super + + + align:start position:0% +have any of these pixels to be super +thin that case turns out to be polom for + + align:start position:0% +thin that case turns out to be polom for + + + align:start position:0% +thin that case turns out to be polom for +squares and hex's open for triangles all + + align:start position:0% +squares and hex's open for triangles all + + + align:start position:0% +squares and hex's open for triangles all +right next + + align:start position:0% +right next + + + align:start position:0% +right next +case is called + + align:start position:0% + + + + align:start position:0% + +thin WR the + + align:start position:0% +thin WR the + + + align:start position:0% +thin WR the +implies in the thin case uh both the + + align:start position:0% +implies in the thin case uh both the + + + align:start position:0% +implies in the thin case uh both the +triangle and the square problems are + + align:start position:0% +triangle and the square problems are + + + align:start position:0% +triangle and the square problems are +empty hard hex's are open what does thin + + align:start position:0% +empty hard hex's are open what does thin + + + align:start position:0% +empty hard hex's are open what does thin +mean thin means every vertex is on the + + align:start position:0% +mean thin means every vertex is on the + + + align:start position:0% +mean thin means every vertex is on the +boundary + + align:start position:0% +boundary + + + align:start position:0% +boundary +okay so super thin is something like + + align:start position:0% +okay so super thin is something like + + + align:start position:0% +okay so super thin is something like +every Edge is on the boundary thin is + + align:start position:0% +every Edge is on the boundary thin is + + + align:start position:0% +every Edge is on the boundary thin is +that every vertex is on the boundary so + + align:start position:0% +that every vertex is on the boundary so + + + align:start position:0% +that every vertex is on the boundary so +for example this part here is thin the + + align:start position:0% +for example this part here is thin the + + + align:start position:0% +for example this part here is thin the +boundar is actually drawn in bold here + + align:start position:0% +boundar is actually drawn in bold here + + + align:start position:0% +boundar is actually drawn in bold here +so if if every vertex has bold edges + + align:start position:0% +so if if every vertex has bold edges + + + align:start position:0% +so if if every vertex has bold edges +incident to it then we call that thin so + + align:start position:0% +incident to it then we call that thin so + + + align:start position:0% +incident to it then we call that thin so +it's a little bit thicker than super + + align:start position:0% +it's a little bit thicker than super + + + align:start position:0% +it's a little bit thicker than super +thin uh so uh it's maybe it's also + + align:start position:0% +thin uh so uh it's maybe it's also + + + align:start position:0% +thin uh so uh it's maybe it's also +easier to think in the duel if you if + + align:start position:0% +easier to think in the duel if you if + + + align:start position:0% +easier to think in the duel if you if +you care to if you draw a Vertex for + + align:start position:0% +you care to if you draw a Vertex for + + + align:start position:0% +you care to if you draw a Vertex for +every pixel in the super thin case there + + align:start position:0% +every pixel in the super thin case there + + + align:start position:0% +every pixel in the super thin case there +are no vertices in the duel in the thin + + align:start position:0% +are no vertices in the duel in the thin + + + align:start position:0% +are no vertices in the duel in the thin +case uh The Duel is super + + align:start position:0% +case uh The Duel is super + + + align:start position:0% +case uh The Duel is super +thin I don't know if that's easier to + + align:start position:0% +thin I don't know if that's easier to + + + align:start position:0% +thin I don't know if that's easier to +think about uh but these cases are + + align:start position:0% +think about uh but these cases are + + + align:start position:0% +think about uh but these cases are +actually hard at least in two out of the + + align:start position:0% +actually hard at least in two out of the + + + align:start position:0% +actually hard at least in two out of the +three pictures one of them we have + + align:start position:0% +three pictures one of them we have + + + align:start position:0% +three pictures one of them we have +already proved + + align:start position:0% +already proved + + + align:start position:0% +already proved +um if you have a Max degree 3 grid graph + + align:start position:0% +um if you have a Max degree 3 grid graph + + + align:start position:0% +um if you have a Max degree 3 grid graph +uh it's degree Max degree is three then + + align:start position:0% +uh it's degree Max degree is three then + + + align:start position:0% +uh it's degree Max degree is three then +it it must be on the boundary because of + + align:start position:0% +it it must be on the boundary because of + + + align:start position:0% +it it must be on the boundary because of +that absent pixel so so we already + + align:start position:0% +that absent pixel so so we already + + + align:start position:0% +that absent pixel so so we already +showed the thin case for squares is hard + + align:start position:0% +showed the thin case for squares is hard + + + align:start position:0% +showed the thin case for squares is hard +Max degree 3 implies uh thin for squares + + align:start position:0% +Max degree 3 implies uh thin for squares + + + align:start position:0% +Max degree 3 implies uh thin for squares +and uh so you might ask what about + + align:start position:0% +and uh so you might ask what about + + + align:start position:0% +and uh so you might ask what about +triangles okay so triangles is so + + align:start position:0% +triangles okay so triangles is so + + + align:start position:0% +triangles okay so triangles is so +finally we get to an actual proof um + + align:start position:0% +finally we get to an actual proof um + + + align:start position:0% +finally we get to an actual proof um +it's going to be the same kind of thing + + align:start position:0% +it's going to be the same kind of thing + + + align:start position:0% +it's going to be the same kind of thing +I'll skip this detail but this is the uh + + align:start position:0% +I'll skip this detail but this is the uh + + + align:start position:0% +I'll skip this detail but this is the uh +planer embedding part so you again we're + + align:start position:0% +planer embedding part so you again we're + + + align:start position:0% +planer embedding part so you again we're +going to reduce from bipartite Max to + + align:start position:0% +going to reduce from bipartite Max to + + + align:start position:0% +going to reduce from bipartite Max to +degre 3 planer hamiltonicity as we did + + align:start position:0% +degre 3 planer hamiltonicity as we did + + + align:start position:0% +degre 3 planer hamiltonicity as we did +before and then we're going to draw it + + align:start position:0% +before and then we're going to draw it + + + align:start position:0% +before and then we're going to draw it +in the plane in some kind of parody + + align:start position:0% +in the plane in some kind of parody + + + align:start position:0% +in the plane in some kind of parody +preserving sense with uh edges routed on + + align:start position:0% +preserving sense with uh edges routed on + + + align:start position:0% +preserving sense with uh edges routed on +the Triangular + + align:start position:0% +the Triangular + + + align:start position:0% +the Triangular +grid okay that's not + + align:start position:0% +grid okay that's not + + + align:start position:0% +grid okay that's not +hard then we have uh very similar + + align:start position:0% +hard then we have uh very similar + + + align:start position:0% +hard then we have uh very similar +looking gadgets although in this case a + + align:start position:0% +looking gadgets although in this case a + + + align:start position:0% +looking gadgets although in this case a +Vertex uh can just be a little triangle + + align:start position:0% +Vertex uh can just be a little triangle + + + align:start position:0% +Vertex uh can just be a little triangle +of dots uh The Edge gadg is going to + + align:start position:0% +of dots uh The Edge gadg is going to + + + align:start position:0% +of dots uh The Edge gadg is going to +look pretty similar it's like a ladder + + align:start position:0% +look pretty similar it's like a ladder + + + align:start position:0% +look pretty similar it's like a ladder +but now the ladder has funny rungs on it + + align:start position:0% +but now the ladder has funny rungs on it + + + align:start position:0% +but now the ladder has funny rungs on it +uh turns are just what you would + + align:start position:0% +uh turns are just what you would + + + align:start position:0% +uh turns are just what you would +expect uh notice we get degree five + + align:start position:0% +expect uh notice we get degree five + + + align:start position:0% +expect uh notice we get degree five +here uh but otherwise things are the + + align:start position:0% +here uh but otherwise things are the + + + align:start position:0% +here uh but otherwise things are the +same you can Traverse either in the loop + + align:start position:0% +same you can Traverse either in the loop + + + align:start position:0% +same you can Traverse either in the loop +back configuration when you have this + + align:start position:0% +back configuration when you have this + + + align:start position:0% +back configuration when you have this +pin joint there you'll be forced to turn + + align:start position:0% +pin joint there you'll be forced to turn + + + align:start position:0% +pin joint there you'll be forced to turn +around there or you do or you zigzag all + + align:start position:0% +around there or you do or you zigzag all + + + align:start position:0% +around there or you do or you zigzag all +the way through and then that's used for + + align:start position:0% +the way through and then that's used for + + + align:start position:0% +the way through and then that's used for +present edges so these are the edges you + + align:start position:0% +present edges so these are the edges you + + + align:start position:0% +present edges so these are the edges you +don't use in the hamiltonan these are + + align:start position:0% +don't use in the hamiltonan these are + + + align:start position:0% +don't use in the hamiltonan these are +edges you do use and there are two types + + align:start position:0% +edges you do use and there are two types + + + align:start position:0% +edges you do use and there are two types +of vertices there's the ones uh of one + + align:start position:0% +of vertices there's the ones uh of one + + + align:start position:0% +of vertices there's the ones uh of one +parody where you always meet here you're + + align:start position:0% +parody where you always meet here you're + + + align:start position:0% +parody where you always meet here you're +kind of meeting with three edges but + + align:start position:0% +kind of meeting with three edges but + + + align:start position:0% +kind of meeting with three edges but +you're kind of meeting on a whole Edge + + align:start position:0% +you're kind of meeting on a whole Edge + + + align:start position:0% +you're kind of meeting on a whole Edge +like that and from here you have the + + align:start position:0% +like that and from here you have the + + + align:start position:0% +like that and from here you have the +choice whether you do this or do this + + align:start position:0% +choice whether you do this or do this + + + align:start position:0% +choice whether you do this or do this +two of them will be zigzags one of them + + align:start position:0% +two of them will be zigzags one of them + + + align:start position:0% +two of them will be zigzags one of them +will be uh double back and then there's + + align:start position:0% +will be uh double back and then there's + + + align:start position:0% +will be uh double back and then there's +the other parody class where you only + + align:start position:0% +the other parody class where you only + + + align:start position:0% +the other parody class where you only +have pin joints these are again just + + align:start position:0% +have pin joints these are again just + + + align:start position:0% +have pin joints these are again just +connected by single edges so they act + + align:start position:0% +connected by single edges so they act + + + align:start position:0% +connected by single edges so they act +just like like we had before okay so + + align:start position:0% +just like like we had before okay so + + + align:start position:0% +just like like we had before okay so +pretty much the same reduction but with + + align:start position:0% +pretty much the same reduction but with + + + align:start position:0% +pretty much the same reduction but with +different in some ways this is an even + + align:start position:0% +different in some ways this is an even + + + align:start position:0% +different in some ways this is an even +easier reduction I + + align:start position:0% +easier reduction I + + + align:start position:0% +easier reduction I +think uh cool now that was Max degree + + align:start position:0% +think uh cool now that was Max degree + + + align:start position:0% +think uh cool now that was Max degree +five what about Max degree 4 so here we + + align:start position:0% +five what about Max degree 4 so here we + + + align:start position:0% +five what about Max degree 4 so here we +had degree 5 vertex there if we kind of + + align:start position:0% +had degree 5 vertex there if we kind of + + + align:start position:0% +had degree 5 vertex there if we kind of +do our same trick of spreading them + + align:start position:0% +do our same trick of spreading them + + + align:start position:0% +do our same trick of spreading them +around you end up with degree four at + + align:start position:0% +around you end up with degree four at + + + align:start position:0% +around you end up with degree four at +most and it Act the same and + + align:start position:0% +most and it Act the same and + + + align:start position:0% +most and it Act the same and +the uh vertices we going to explode into + + align:start position:0% +the uh vertices we going to explode into + + + align:start position:0% +the uh vertices we going to explode into +a + + align:start position:0% +a + + + align:start position:0% +a +hexagon and it + + align:start position:0% +hexagon and it + + + align:start position:0% +hexagon and it +works okay so + + align:start position:0% +works okay so + + + align:start position:0% +works okay so +uh I should + + align:start position:0% + + + + align:start position:0% + +say Max degree + + align:start position:0% + + + + align:start position:0% + +4 triangle is NP + + align:start position:0% +4 triangle is NP + + + align:start position:0% +4 triangle is NP +hard this red should also be thin + + align:start position:0% +hard this red should also be thin + + + align:start position:0% +hard this red should also be thin +previous one may have also been thin but + + align:start position:0% +previous one may have also been thin but + + + align:start position:0% +previous one may have also been thin but +uh again all of the vertices are on the + + align:start position:0% +uh again all of the vertices are on the + + + align:start position:0% +uh again all of the vertices are on the +boundary so this is the thin triangle is + + align:start position:0% +boundary so this is the thin triangle is + + + align:start position:0% +boundary so this is the thin triangle is +hard Max degree four triangle is hard we + + align:start position:0% +hard Max degree four triangle is hard we + + + align:start position:0% +hard Max degree four triangle is hard we +did this one so we've done all the + + align:start position:0% +did this one so we've done all the + + + align:start position:0% +did this one so we've done all the +hardness + + align:start position:0% +hardness + + + align:start position:0% +hardness +proofs okay that will cease to be the + + align:start position:0% +proofs okay that will cease to be the + + + align:start position:0% +proofs okay that will cease to be the +case in a moment uh okay + + align:start position:0% +case in a moment uh okay + + + align:start position:0% +case in a moment uh okay +here's one more thing Max so what about + + align:start position:0% +here's one more thing Max so what about + + + align:start position:0% +here's one more thing Max so what about +hex grids is there any I hav't mention + + align:start position:0% +hex grids is there any I hav't mention + + + align:start position:0% +hex grids is there any I hav't mention +any hardness for hex grids yet uh and + + align:start position:0% +any hardness for hex grids yet uh and + + + align:start position:0% +any hardness for hex grids yet uh and +one thing we know is Max degree 3 + + align:start position:0% +one thing we know is Max degree 3 + + + align:start position:0% +one thing we know is Max degree 3 +already knew squares but also + + align:start position:0% + + + + align:start position:0% + +hexagons are NP hard now this is not so + + align:start position:0% +hexagons are NP hard now this is not so + + + align:start position:0% +hexagons are NP hard now this is not so +impressive uh every vertex in HEX grid + + align:start position:0% +impressive uh every vertex in HEX grid + + + align:start position:0% +impressive uh every vertex in HEX grid +has a degree at most three but you can't + + align:start position:0% +has a degree at most three but you can't + + + align:start position:0% +has a degree at most three but you can't +hope for two so that's the best you can + + align:start position:0% +hope for two so that's the best you can + + + align:start position:0% +hope for two so that's the best you can +hope for Max degree characterization + + align:start position:0% +hope for Max degree characterization + + + align:start position:0% +hope for Max degree characterization +with respect to hex grid okay uh this + + align:start position:0% +with respect to hex grid okay uh this + + + align:start position:0% +with respect to hex grid okay uh this +proof is tricky + + align:start position:0% + + + + align:start position:0% + +um maybe uh before I go there let me + + align:start position:0% +um maybe uh before I go there let me + + + align:start position:0% +um maybe uh before I go there let me +just mention one other result so this is + + align:start position:0% +just mention one other result so this is + + + align:start position:0% +just mention one other result so this is +delayed one other thing is uh one other + + align:start position:0% +delayed one other thing is uh one other + + + align:start position:0% +delayed one other thing is uh one other +notion you can think about for a grid + + align:start position:0% +notion you can think about for a grid + + + align:start position:0% +notion you can think about for a grid +graphs is called polygonal grid graphs + + align:start position:0% +graphs is called polygonal grid graphs + + + align:start position:0% +graphs is called polygonal grid graphs +and that's what's supposed to be + + align:start position:0% +and that's what's supposed to be + + + align:start position:0% +and that's what's supposed to be +Illustrated here polygonal is kind of + + align:start position:0% +Illustrated here polygonal is kind of + + + align:start position:0% +Illustrated here polygonal is kind of +the opposite of super thin so super thin + + align:start position:0% +the opposite of super thin so super thin + + + align:start position:0% +the opposite of super thin so super thin +we had an an edge that had uh non pixel + + align:start position:0% +we had an an edge that had uh non pixel + + + align:start position:0% +we had an an edge that had uh non pixel +on both + + align:start position:0% +on both + + + align:start position:0% +on both +sides in polygonal every Edge has a + + align:start position:0% +sides in polygonal every Edge has a + + + align:start position:0% +sides in polygonal every Edge has a +pixel on at least one of the two sides + + align:start position:0% +pixel on at least one of the two sides + + + align:start position:0% +pixel on at least one of the two sides +okay so you never have you never have an + + align:start position:0% +okay so you never have you never have an + + + align:start position:0% +okay so you never have you never have an +edge between two holes or a hole on the + + align:start position:0% +edge between two holes or a hole on the + + + align:start position:0% +edge between two holes or a hole on the +outside face that's the polygonal + + align:start position:0% +outside face that's the polygonal + + + align:start position:0% +outside face that's the polygonal +situation uh and so that's something you + + align:start position:0% +situation uh and so that's something you + + + align:start position:0% +situation uh and so that's something you +might assume it's sort of like saying + + align:start position:0% +might assume it's sort of like saying + + + align:start position:0% +might assume it's sort of like saying +you had a polygon and then you sort of + + align:start position:0% +you had a polygon and then you sort of + + + align:start position:0% +you had a polygon and then you sort of +took the interior of the polygon whereas + + align:start position:0% +took the interior of the polygon whereas + + + align:start position:0% +took the interior of the polygon whereas +here this was not really a polygon + + align:start position:0% +here this was not really a polygon + + + align:start position:0% +here this was not really a polygon +because it's like there was a doubled + + align:start position:0% +because it's like there was a doubled + + + align:start position:0% +because it's like there was a doubled +Edge there or something that's not + + align:start position:0% +Edge there or something that's not + + + align:start position:0% +Edge there or something that's not +really a nice picture so polygonal is + + align:start position:0% +really a nice picture so polygonal is + + + align:start position:0% +really a nice picture so polygonal is +something you might hope for in in the + + align:start position:0% +something you might hope for in in the + + + align:start position:0% +something you might hope for in in the +Practical applications which we will get + + align:start position:0% +Practical applications which we will get + + + align:start position:0% +Practical applications which we will get +to + + align:start position:0% +to + + + align:start position:0% +to +soon funny thing is uh for polygonal + + align:start position:0% +soon funny thing is uh for polygonal + + + align:start position:0% +soon funny thing is uh for polygonal +triangular grid graphs the problem is + + align:start position:0% +triangular grid graphs the problem is + + + align:start position:0% +triangular grid graphs the problem is +polinomial and for + + align:start position:0% +polinomial and for + + + align:start position:0% +polinomial and for +polygonal uh hex grid graphs the problem + + align:start position:0% +polygonal uh hex grid graphs the problem + + + align:start position:0% +polygonal uh hex grid graphs the problem +is NP + + align:start position:0% +is NP + + + align:start position:0% +is NP +hard and for polygonal Square grid + + align:start position:0% +hard and for polygonal Square grid + + + align:start position:0% +hard and for polygonal Square grid +graphs we don't + + align:start position:0% +graphs we don't + + + align:start position:0% +graphs we don't +know so another open problem + + align:start position:0% +know so another open problem + + + align:start position:0% +know so another open problem +okay I I won't prove this I think again + + align:start position:0% +okay I I won't prove this I think again + + + align:start position:0% +okay I I won't prove this I think again +this is almost always feasible there's + + align:start position:0% +this is almost always feasible there's + + + align:start position:0% +this is almost always feasible there's +almost always a hamiltonian path uh for + + align:start position:0% +almost always a hamiltonian path uh for + + + align:start position:0% +almost always a hamiltonian path uh for +this I'm guessing it follows from the + + align:start position:0% +this I'm guessing it follows from the + + + align:start position:0% +this I'm guessing it follows from the +same proof but uh let's go into this + + align:start position:0% +same proof but uh let's go into this + + + align:start position:0% +same proof but uh let's go into this +this proof Max degree well hex grid + + align:start position:0% +this proof Max degree well hex grid + + + align:start position:0% +this proof Max degree well hex grid +hardness again there's a drawing step + + align:start position:0% +hardness again there's a drawing step + + + align:start position:0% +hardness again there's a drawing step +you're given some bipartite Max degree 3 + + align:start position:0% +you're given some bipartite Max degree 3 + + + align:start position:0% +you're given some bipartite Max degree 3 +graph uh and bipartite planer Max degree + + align:start position:0% +graph uh and bipartite planer Max degree + + + align:start position:0% +graph uh and bipartite planer Max degree +3 graph uh and then we're going to draw + + align:start position:0% +3 graph uh and then we're going to draw + + + align:start position:0% +3 graph uh and then we're going to draw +it on the hex grid um in this case we're + + align:start position:0% +it on the hex grid um in this case we're + + + align:start position:0% +it on the hex grid um in this case we're +going to represent variables by sort of + + align:start position:0% +going to represent variables by sort of + + + align:start position:0% +going to represent variables by sort of +horizontal + + align:start position:0% +horizontal + + + align:start position:0% +horizontal +strips uh just because that's what is a + + align:start position:0% +strips uh just because that's what is a + + + align:start position:0% +strips uh just because that's what is a +little bit easier to do so it turns out + + align:start position:0% +little bit easier to do so it turns out + + + align:start position:0% +little bit easier to do so it turns out +uh I think turns are really annoying on + + align:start position:0% +uh I think turns are really annoying on + + + align:start position:0% +uh I think turns are really annoying on +the hex Grid it's hard to do a turn so + + align:start position:0% +the hex Grid it's hard to do a turn so + + + align:start position:0% +the hex Grid it's hard to do a turn so +uh we're going to focus our turn + + align:start position:0% +uh we're going to focus our turn + + + align:start position:0% +uh we're going to focus our turn +attention Within These Little rectangles + + align:start position:0% +attention Within These Little rectangles + + + align:start position:0% +attention Within These Little rectangles +and turns out you can draw everything in + + align:start position:0% +and turns out you can draw everything in + + + align:start position:0% +and turns out you can draw everything in +such a way that all of the edges are + + align:start position:0% +such a way that all of the edges are + + + align:start position:0% +such a way that all of the edges are +straight lines straight line segments if + + align:start position:0% +straight lines straight line segments if + + + align:start position:0% +straight lines straight line segments if +if you grow the vertices to be these + + align:start position:0% +if you grow the vertices to be these + + + align:start position:0% +if you grow the vertices to be these +longer horizontal things okay so believe + + align:start position:0% +longer horizontal things okay so believe + + + align:start position:0% +longer horizontal things okay so believe +believe + + align:start position:0% +believe + + + align:start position:0% +believe +that uh + + align:start position:0% +that uh + + + align:start position:0% +that uh +then main idea is is a very similar kind + + align:start position:0% +then main idea is is a very similar kind + + + align:start position:0% +then main idea is is a very similar kind +of thing uh in general they in this case + + align:start position:0% +of thing uh in general they in this case + + + align:start position:0% +of thing uh in general they in this case +they're going to draw the pictures and + + align:start position:0% +they're going to draw the pictures and + + + align:start position:0% +they're going to draw the pictures and +they're going to draw all of the forced + + align:start position:0% +they're going to draw all of the forced + + + align:start position:0% +they're going to draw all of the forced +edges that must be in there uh and here + + align:start position:0% +edges that must be in there uh and here + + + align:start position:0% +edges that must be in there uh and here +they haven't drawn the part in the + + align:start position:0% +they haven't drawn the part in the + + + align:start position:0% +they haven't drawn the part in the +middle there's two ways to fill it in + + align:start position:0% +middle there's two ways to fill it in + + + align:start position:0% +middle there's two ways to fill it in +essentially you could zigzag back and + + align:start position:0% +essentially you could zigzag back and + + + align:start position:0% +essentially you could zigzag back and +forth just like before or you could go + + align:start position:0% +forth just like before or you could go + + + align:start position:0% +forth just like before or you could go +there and come back just like before so + + align:start position:0% +there and come back just like before so + + + align:start position:0% +there and come back just like before so +Edge Gadget looks pretty + + align:start position:0% + + + + align:start position:0% + +reasonable uh these are some more + + align:start position:0% +reasonable uh these are some more + + + align:start position:0% +reasonable uh these are some more +gadgets uh these are like subroutines + + align:start position:0% +gadgets uh these are like subroutines + + + align:start position:0% +gadgets uh these are like subroutines +they're going to use uh they're named + + align:start position:0% +they're going to use uh they're named + + + align:start position:0% +they're going to use uh they're named +and they have color patterns to give you + + align:start position:0% +and they have color patterns to give you + + + align:start position:0% +and they have color patterns to give you +a sense this is going to be the center + + align:start position:0% +a sense this is going to be the center + + + align:start position:0% +a sense this is going to be the center +of a + + align:start position:0% +of a + + + align:start position:0% +of a +Vertex uh and there's a few different + + align:start position:0% +Vertex uh and there's a few different + + + align:start position:0% +Vertex uh and there's a few different +things you could do with that uh this is + + align:start position:0% +things you could do with that uh this is + + + align:start position:0% +things you could do with that uh this is +some kind of turn Gadget that's what I + + align:start position:0% +some kind of turn Gadget that's what I + + + align:start position:0% +some kind of turn Gadget that's what I +called it they call it uh something a + + align:start position:0% +called it they call it uh something a + + + align:start position:0% +called it they call it uh something a +little different I think a rosette but + + align:start position:0% +little different I think a rosette but + + + align:start position:0% +little different I think a rosette but +uh you can sort of zigzag + + align:start position:0% +uh you can sort of zigzag + + + align:start position:0% +uh you can sort of zigzag +or you can kind of go there and double + + align:start position:0% +or you can kind of go there and double + + + align:start position:0% +or you can kind of go there and double +back but you end up with different + + align:start position:0% +back but you end up with different + + + align:start position:0% +back but you end up with different +orientations at the ends this is what + + align:start position:0% +orientations at the ends this is what + + + align:start position:0% +orientations at the ends this is what +they call a U-turn um again these edges + + align:start position:0% +they call a U-turn um again these edges + + + align:start position:0% +they call a U-turn um again these edges +are forced you can either use it as a + + align:start position:0% +are forced you can either use it as a + + + align:start position:0% +are forced you can either use it as a +zigzag or they could both kind of cancel + + align:start position:0% +zigzag or they could both kind of cancel + + + align:start position:0% +zigzag or they could both kind of cancel +each other out sort of don't don't meet + + align:start position:0% +each other out sort of don't don't meet + + + align:start position:0% +each other out sort of don't don't meet +each other so you get different kind of + + align:start position:0% +each other so you get different kind of + + + align:start position:0% +each other so you get different kind of +connectivity okay with that in mind here + + align:start position:0% +connectivity okay with that in mind here + + + align:start position:0% +connectivity okay with that in mind here +is all the vertex + + align:start position:0% +is all the vertex + + + align:start position:0% +is all the vertex +gadgets uh so I I I I don't know all the + + align:start position:0% +gadgets uh so I I I I don't know all the + + + align:start position:0% +gadgets uh so I I I I don't know all the +details here + + align:start position:0% +details here + + + align:start position:0% +details here +um I think there's a lot of uh cases + + align:start position:0% +um I think there's a lot of uh cases + + + align:start position:0% +um I think there's a lot of uh cases +because of the different ways things + + align:start position:0% +because of the different ways things + + + align:start position:0% +because of the different ways things +could be connected you could have like + + align:start position:0% +could be connected you could have like + + + align:start position:0% +could be connected you could have like +one on top of the notice the dash things + + align:start position:0% +one on top of the notice the dash things + + + align:start position:0% +one on top of the notice the dash things +are the rectangles that I had before + + align:start position:0% +are the rectangles that I had before + + + align:start position:0% +are the rectangles that I had before +normally they'd be really spread out uh + + align:start position:0% +normally they'd be really spread out uh + + + align:start position:0% +normally they'd be really spread out uh +so maybe you have two on the bottom one + + align:start position:0% +so maybe you have two on the bottom one + + + align:start position:0% +so maybe you have two on the bottom one +on the top here we have two on the top + + align:start position:0% +on the top here we have two on the top + + + align:start position:0% +on the top here we have two on the top +one on the bottom and they could be + + align:start position:0% +one on the bottom and they could be + + + align:start position:0% +one on the bottom and they could be +oriented like this or oriented like that + + align:start position:0% +oriented like this or oriented like that + + + align:start position:0% +oriented like this or oriented like that +so there's a lot of different cases as a + + align:start position:0% +so there's a lot of different cases as a + + + align:start position:0% +so there's a lot of different cases as a +result the the core part in the middle + + align:start position:0% +result the the core part in the middle + + + align:start position:0% +result the the core part in the middle +is the same it's pretty much like the + + align:start position:0% +is the same it's pretty much like the + + + align:start position:0% +is the same it's pretty much like the +examples we had before + + align:start position:0% +examples we had before + + + align:start position:0% +examples we had before +of + + align:start position:0% +of + + + align:start position:0% +of +uh essentially like a little 3x3 Square + + align:start position:0% +uh essentially like a little 3x3 Square + + + align:start position:0% +uh essentially like a little 3x3 Square +for the square case or a little triangle + + align:start position:0% +for the square case or a little triangle + + + align:start position:0% +for the square case or a little triangle +in the Triangle case little bit bigger + + align:start position:0% +in the Triangle case little bit bigger + + + align:start position:0% +in the Triangle case little bit bigger +in a hex it's basically a cycle with an + + align:start position:0% +in a hex it's basically a cycle with an + + + align:start position:0% +in a hex it's basically a cycle with an +extra dot in the middle um but then + + align:start position:0% +extra dot in the middle um but then + + + align:start position:0% +extra dot in the middle um but then +there's this is this was a U-turn Gadget + + align:start position:0% +there's this is this was a U-turn Gadget + + + align:start position:0% +there's this is this was a U-turn Gadget +so if something was coming up here uh + + align:start position:0% +so if something was coming up here uh + + + align:start position:0% +so if something was coming up here uh +you could just sort of turn back around + + align:start position:0% +you could just sort of turn back around + + + align:start position:0% +you could just sort of turn back around +if you don't want to use the edge uh I + + align:start position:0% +if you don't want to use the edge uh I + + + align:start position:0% +if you don't want to use the edge uh I +think these are prob well yeah so + + align:start position:0% +think these are prob well yeah so + + + align:start position:0% +think these are prob well yeah so +there's probably also two parody classes + + align:start position:0% +there's probably also two parody classes + + + align:start position:0% +there's probably also two parody classes +uh there's these turn gadgets + + align:start position:0% +uh there's these turn gadgets + + + align:start position:0% +uh there's these turn gadgets +and it + + align:start position:0% +and it + + + align:start position:0% +and it +works okay so but it's + + align:start position:0% + + + + align:start position:0% + +complicated I think that's I all I'll + + align:start position:0% +complicated I think that's I all I'll + + + align:start position:0% +complicated I think that's I all I'll +say about various grid graphs yeah I + + align:start position:0% +say about various grid graphs yeah I + + + align:start position:0% +say about various grid graphs yeah I +think you said that thin hexagonal grids + + align:start position:0% +think you said that thin hexagonal grids + + + align:start position:0% +think you said that thin hexagonal grids +were open so th means the vertex every + + align:start position:0% +were open so th means the vertex every + + + align:start position:0% +were open so th means the vertex every +vertex on the + + align:start position:0% +vertex on the + + + align:start position:0% +vertex on the +boundary nebor right no that's it's not + + align:start position:0% +boundary nebor right no that's it's not + + + align:start position:0% +boundary nebor right no that's it's not +necessarily the same so if you have hex + + align:start position:0% +necessarily the same so if you have hex + + + align:start position:0% +necessarily the same so if you have hex +grid I mean this could still be a + + align:start position:0% +grid I mean this could still be a + + + align:start position:0% +grid I mean this could still be a +boundary cycle and you still have degree + + align:start position:0% +boundary cycle and you still have degree + + + align:start position:0% +boundary cycle and you still have degree +3 vertex X something like this part is + + align:start position:0% +3 vertex X something like this part is + + + align:start position:0% +3 vertex X something like this part is +thin I'm guessing you could complete + + align:start position:0% +thin I'm guessing you could complete + + + align:start position:0% +thin I'm guessing you could complete +that so they're probably very special so + + align:start position:0% +that so they're probably very special so + + + align:start position:0% +that so they're probably very special so +I could imagine the thin hex grids are a + + align:start position:0% +I could imagine the thin hex grids are a + + + align:start position:0% +I could imagine the thin hex grids are a +polinomial but it's not known okay uh + + align:start position:0% +polinomial but it's not known okay uh + + + align:start position:0% +polinomial but it's not known okay uh +one more picture this is an actual + + align:start position:0% +one more picture this is an actual + + + align:start position:0% +one more picture this is an actual +explicitly constructed example from that + + align:start position:0% +explicitly constructed example from that + + + align:start position:0% +explicitly constructed example from that +graph to this uh crazy gadgets but now + + align:start position:0% +graph to this uh crazy gadgets but now + + + align:start position:0% +graph to this uh crazy gadgets but now +you can see a little better what the + + align:start position:0% +you can see a little better what the + + + align:start position:0% +you can see a little better what the +rectangles look like if you want to + + align:start position:0% +rectangles look like if you want to + + + align:start position:0% +rectangles look like if you want to +stretch something out you just make + + align:start position:0% +stretch something out you just make + + + align:start position:0% +stretch something out you just make +there's always horizontal wires that you + + align:start position:0% +there's always horizontal wires that you + + + align:start position:0% +there's always horizontal wires that you +can stretch out and I keep them wires + + align:start position:0% +can stretch out and I keep them wires + + + align:start position:0% +can stretch out and I keep them wires +there's horizontal pieces of edge + + align:start position:0% +there's horizontal pieces of edge + + + align:start position:0% +there's horizontal pieces of edge +gadgets that you can just stretch out uh + + align:start position:0% +gadgets that you can just stretch out uh + + + align:start position:0% +gadgets that you can just stretch out uh +so that you end up firing and hitting + + align:start position:0% +so that you end up firing and hitting + + + align:start position:0% +so that you end up firing and hitting +the the next vertex which is this + + align:start position:0% +the the next vertex which is this + + + align:start position:0% +the the next vertex which is this +rectangle and when you spread out the + + align:start position:0% +rectangle and when you spread out the + + + align:start position:0% +rectangle and when you spread out the +rectangles you have to stretch out these + + align:start position:0% +rectangles you have to stretch out these + + + align:start position:0% +rectangles you have to stretch out these +diagonal + + align:start position:0% +diagonal + + + align:start position:0% +diagonal +shots cool that was hex grid graphs why + + align:start position:0% +shots cool that was hex grid graphs why + + + align:start position:0% +shots cool that was hex grid graphs why +do we care about hex grid graphs so much + + align:start position:0% +do we care about hex grid graphs so much + + + align:start position:0% +do we care about hex grid graphs so much +because Settlers of + + align:start position:0% +because Settlers of + + + align:start position:0% +because Settlers of +Katan and various other board games that + + align:start position:0% +Katan and various other board games that + + + align:start position:0% +Katan and various other board games that +have a hex grid um now has anyone here + + align:start position:0% +have a hex grid um now has anyone here + + + align:start position:0% +have a hex grid um now has anyone here +not played of Katon okay a few um Bas + + align:start position:0% +not played of Katon okay a few um Bas + + + align:start position:0% +not played of Katon okay a few um Bas +there there's there's a whole game to it + + align:start position:0% +there there's there's a whole game to it + + + align:start position:0% +there there's there's a whole game to it +but uh + + align:start position:0% +but uh + + + align:start position:0% +but uh +what what I'm going to focus on is uh + + align:start position:0% +what what I'm going to focus on is uh + + + align:start position:0% +what what I'm going to focus on is uh +this card it's called longest + + align:start position:0% +this card it's called longest + + + align:start position:0% +this card it's called longest +road so um in general you're + + align:start position:0% +road so um in general you're + + + align:start position:0% +road so um in general you're +constructing cities don't worry about + + align:start position:0% +constructing cities don't worry about + + + align:start position:0% +constructing cities don't worry about +cities uh but you're constructing these + + align:start position:0% +cities uh but you're constructing these + + + align:start position:0% +cities uh but you're constructing these +Road segments they are edges on the hex + + align:start position:0% +Road segments they are edges on the hex + + + align:start position:0% +Road segments they are edges on the hex +grid and longest road says that you get + + align:start position:0% +grid and longest road says that you get + + + align:start position:0% +grid and longest road says that you get +two points two victory points if you + + align:start position:0% +two points two victory points if you + + + align:start position:0% +two points two victory points if you +have the longest Road meaning the + + align:start position:0% +have the longest Road meaning the + + + align:start position:0% +have the longest Road meaning the +longest path that can be formed using + + align:start position:0% +longest path that can be formed using + + + align:start position:0% +longest path that can be formed using +edges of your color versus edges of + + align:start position:0% +edges of your color versus edges of + + + align:start position:0% +edges of your color versus edges of +anyone else's color then you get two + + align:start position:0% +anyone else's color then you get two + + + align:start position:0% +anyone else's color then you get two +points so here's the idea uh for + + align:start position:0% +points so here's the idea uh for + + + align:start position:0% +points so here's the idea uh for +Settlers of Katan has Randomness and + + align:start position:0% +Settlers of Katan has Randomness and + + + align:start position:0% +Settlers of Katan has Randomness and +stuff like that but again if we look at + + align:start position:0% +stuff like that but again if we look at + + + align:start position:0% +stuff like that but again if we look at +a mate in one problem uh that that goes + + align:start position:0% +a mate in one problem uh that that goes + + + align:start position:0% +a mate in one problem uh that that goes +out the window it's just can I win in + + align:start position:0% +out the window it's just can I win in + + + align:start position:0% +out the window it's just can I win in +this one move there's no Randomness to + + align:start position:0% +this one move there's no Randomness to + + + align:start position:0% +this one move there's no Randomness to +that uh let's suppose you have tons of + + align:start position:0% +that uh let's suppose you have tons of + + + align:start position:0% +that uh let's suppose you have tons of +resources this is what you need to build + + align:start position:0% +resources this is what you need to build + + + align:start position:0% +resources this is what you need to build +a road and inconveniently your opponents + + align:start position:0% +a road and inconveniently your opponents + + + align:start position:0% +a road and inconveniently your opponents +have built cities and things in all of + + align:start position:0% +have built cities and things in all of + + + align:start position:0% +have built cities and things in all of +these white spots + + align:start position:0% +these white spots + + + align:start position:0% +these white spots +so you're not allowed to build roads + + align:start position:0% +so you're not allowed to build roads + + + align:start position:0% +so you're not allowed to build roads +there that's just part of the rules uh + + align:start position:0% +there that's just part of the rules uh + + + align:start position:0% +there that's just part of the rules uh +so that's the opponents form obstacles + + align:start position:0% +so that's the opponents form obstacles + + + align:start position:0% +so that's the opponents form obstacles +and then uh because you have infinite + + align:start position:0% +and then uh because you have infinite + + + align:start position:0% +and then uh because you have infinite +cache you can basically build the entire + + align:start position:0% +cache you can basically build the entire + + + align:start position:0% +cache you can basically build the entire +grid graph here and then to figure out + + align:start position:0% +grid graph here and then to figure out + + + align:start position:0% +grid graph here and then to figure out +whether there's a really long road + + align:start position:0% +whether there's a really long road + + + align:start position:0% +whether there's a really long road +namely uh a road length n where n is the + + align:start position:0% +namely uh a road length n where n is the + + + align:start position:0% +namely uh a road length n where n is the +number of pixels that were not occupied + + align:start position:0% +number of pixels that were not occupied + + + align:start position:0% +number of pixels that were not occupied +by opponents number of dots that are not + + align:start position:0% +by opponents number of dots that are not + + + align:start position:0% +by opponents number of dots that are not +occupied by opponents uh is MP + + align:start position:0% +occupied by opponents uh is MP + + + align:start position:0% +occupied by opponents uh is MP +complete cool and your opponent has a a + + align:start position:0% +complete cool and your opponent has a a + + + align:start position:0% +complete cool and your opponent has a a +slightly shorter road so you really have + + align:start position:0% +slightly shorter road so you really have + + + align:start position:0% +slightly shorter road so you really have +to distinguish uh whether you've uh + + align:start position:0% +to distinguish uh whether you've uh + + + align:start position:0% +to distinguish uh whether you've uh +whether you have the longest road in + + align:start position:0% +whether you have the longest road in + + + align:start position:0% +whether you have the longest road in +fact I like to say Main in zero is MP + + align:start position:0% +fact I like to say Main in zero is MP + + + align:start position:0% +fact I like to say Main in zero is MP +complete deciding whether you've already + + align:start position:0% +complete deciding whether you've already + + + align:start position:0% +complete deciding whether you've already +won the game is MP complete right now + + align:start position:0% +won the game is MP complete right now + + + align:start position:0% +won the game is MP complete right now +you don't even need cash it's just I + + align:start position:0% +you don't even need cash it's just I + + + align:start position:0% +you don't even need cash it's just I +give you a configuration do you have the + + align:start position:0% +give you a configuration do you have the + + + align:start position:0% +give you a configuration do you have the +longest road is empty hard so it's the + + align:start position:0% +longest road is empty hard so it's the + + + align:start position:0% +longest road is empty hard so it's the +only main zero hardness result I know of + + align:start position:0% +only main zero hardness result I know of + + + align:start position:0% +only main zero hardness result I know of +maybe we can find + + align:start position:0% +maybe we can find + + + align:start position:0% +maybe we can find +more okay so that's why hex grids are + + align:start position:0% +more okay so that's why hex grids are + + + align:start position:0% +more okay so that's why hex grids are +cool + + align:start position:0% +cool + + + align:start position:0% +cool +let's do some more games uh here's + + align:start position:0% +let's do some more games uh here's + + + align:start position:0% +let's do some more games uh here's +another Nick puzzle slitherlink their + + align:start position:0% +another Nick puzzle slitherlink their + + + align:start position:0% +another Nick puzzle slitherlink their +more famous ones uh so you're given a + + align:start position:0% +more famous ones uh so you're given a + + + align:start position:0% +more famous ones uh so you're given a +grid of squares each square is either + + align:start position:0% +grid of squares each square is either + + + align:start position:0% +grid of squares each square is either +blank meaning no constraint or there's a + + align:start position:0% +blank meaning no constraint or there's a + + + align:start position:0% +blank meaning no constraint or there's a +number saying there should be exactly + + align:start position:0% +number saying there should be exactly + + + align:start position:0% +number saying there should be exactly +two edges among those four and there + + align:start position:0% +two edges among those four and there + + + align:start position:0% +two edges among those four and there +should be exactly three edges among + + align:start position:0% +should be exactly three edges among + + + align:start position:0% +should be exactly three edges among +those four your goal is to find a cycle + + align:start position:0% +those four your goal is to find a cycle + + + align:start position:0% +those four your goal is to find a cycle +not hamiltonian but just a cycle it + + align:start position:0% +not hamiltonian but just a cycle it + + + align:start position:0% +not hamiltonian but just a cycle it +doesn't visit all the dots uh that + + align:start position:0% +doesn't visit all the dots uh that + + + align:start position:0% +doesn't visit all the dots uh that +satisfies that neighboring constraint so + + align:start position:0% +satisfies that neighboring constraint so + + + align:start position:0% +satisfies that neighboring constraint so +here there were exactly two here there + + align:start position:0% +here there were exactly two here there + + + align:start position:0% +here there were exactly two here there +exactly three uh edges in your + + align:start position:0% +exactly three uh edges in your + + + align:start position:0% +exactly three uh edges in your +cycle okay this is the very first puzzle + + align:start position:0% +cycle okay this is the very first puzzle + + + align:start position:0% +cycle okay this is the very first puzzle +on the website again there are books of + + align:start position:0% +on the website again there are books of + + + align:start position:0% +on the website again there are books of +slitherlink puzzles and here is uh a + + align:start position:0% +slitherlink puzzles and here is uh a + + + align:start position:0% +slitherlink puzzles and here is uh a +little over Overkill of hardness proof + + align:start position:0% +little over Overkill of hardness proof + + + align:start position:0% +little over Overkill of hardness proof +but in one slide uh so this is a + + align:start position:0% +but in one slide uh so this is a + + + align:start position:0% +but in one slide uh so this is a +reduction from hamiltonicity + + align:start position:0% +reduction from hamiltonicity + + + align:start position:0% +reduction from hamiltonicity +in planer graphs so you take any planer + + align:start position:0% +in planer graphs so you take any planer + + + align:start position:0% +in planer graphs so you take any planer +graph and draw it in the grid this is + + align:start position:0% +graph and draw it in the grid this is + + + align:start position:0% +graph and draw it in the grid this is +one of the very first steps we did + + align:start position:0% +one of the very first steps we did + + + align:start position:0% +one of the very first steps we did +today um and then if you do that there + + align:start position:0% +today um and then if you do that there + + + align:start position:0% +today um and then if you do that there +are two types of vertices there's the + + align:start position:0% +are two types of vertices there's the + + + align:start position:0% +are two types of vertices there's the +ones you have to visit and there's the + + align:start position:0% +ones you have to visit and there's the + + + align:start position:0% +ones you have to visit and there's the +ones you don't have to visit now we know + + align:start position:0% +ones you don't have to visit now we know + + + align:start position:0% +ones you don't have to visit now we know +grid graphs are hard so we could + + align:start position:0% +grid graphs are hard so we could + + + align:start position:0% +grid graphs are hard so we could +actually assume all of the vertices have + + align:start position:0% +actually assume all of the vertices have + + + align:start position:0% +actually assume all of the vertices have +to be visited but uh for whatever reason + + align:start position:0% +to be visited but uh for whatever reason + + + align:start position:0% +to be visited but uh for whatever reason +this proof did not do that probably at + + align:start position:0% +this proof did not do that probably at + + + align:start position:0% +this proof did not do that probably at +that this was back in 2000 so at that + + align:start position:0% +that this was back in 2000 so at that + + + align:start position:0% +that this was back in 2000 so at that +point maybe it was not so well + + align:start position:0% +point maybe it was not so well + + + align:start position:0% +point maybe it was not so well +known uh but these days grid graph + + align:start position:0% +known uh but these days grid graph + + + align:start position:0% +known uh but these days grid graph +Hamilton is used a lot but probably not + + align:start position:0% +Hamilton is used a lot but probably not + + + align:start position:0% +Hamilton is used a lot but probably not +so much then uh so anyway there's this + + align:start position:0% +so much then uh so anyway there's this + + + align:start position:0% +so much then uh so anyway there's this +gadget which is uh you can do whatever + + align:start position:0% +gadget which is uh you can do whatever + + + align:start position:0% +gadget which is uh you can do whatever +you want basically uh these are the + + align:start position:0% +you want basically uh these are the + + + align:start position:0% +you want basically uh these are the +vertices that don't need to be visited + + align:start position:0% +vertices that don't need to be visited + + + align:start position:0% +vertices that don't need to be visited +the key Gadget is this one so let's + + align:start position:0% +the key Gadget is this one so let's + + + align:start position:0% +the key Gadget is this one so let's +focus our attention here we have these + + align:start position:0% +focus our attention here we have these + + + align:start position:0% +focus our attention here we have these +ones which means the cycle must come + + align:start position:0% +ones which means the cycle must come + + + align:start position:0% +ones which means the cycle must come +here and so collectively these are going + + align:start position:0% +here and so collectively these are going + + + align:start position:0% +here and so collectively these are going +to form hamiltonian cycle constraints + + align:start position:0% +to form hamiltonian cycle constraints + + + align:start position:0% +to form hamiltonian cycle constraints +you're building a cycle and you have to + + align:start position:0% +you're building a cycle and you have to + + + align:start position:0% +you're building a cycle and you have to +visit these ones now it turns out no + + align:start position:0% +visit these ones now it turns out no + + + align:start position:0% +visit these ones now it turns out no +matter which end you come in and which + + align:start position:0% +matter which end you come in and which + + + align:start position:0% +matter which end you come in and which +end you leave you can visit all of the + + align:start position:0% +end you leave you can visit all of the + + + align:start position:0% +end you leave you can visit all of the +ones you can be adjacent to all of the + + align:start position:0% +ones you can be adjacent to all of the + + + align:start position:0% +ones you can be adjacent to all of the +ones so with different turns are going + + align:start position:0% +ones so with different turns are going + + + align:start position:0% +ones so with different turns are going +straight and so if there is a + + align:start position:0% +straight and so if there is a + + + align:start position:0% +straight and so if there is a +hamiltonian cycle you'll be able to + + align:start position:0% +hamiltonian cycle you'll be able to + + + align:start position:0% +hamiltonian cycle you'll be able to +visit all the + + align:start position:0% +visit all the + + + align:start position:0% +visit all the +ones and conversely if you can visit all + + align:start position:0% +ones and conversely if you can visit all + + + align:start position:0% +ones and conversely if you can visit all +the ones that must be a hamiltonian + + align:start position:0% +the ones that must be a hamiltonian + + + align:start position:0% +the ones that must be a hamiltonian +cycle the one extra thing we need to say + + align:start position:0% +cycle the one extra thing we need to say + + + align:start position:0% +cycle the one extra thing we need to say +uh if you just glue these gadgets + + align:start position:0% +uh if you just glue these gadgets + + + align:start position:0% +uh if you just glue these gadgets +together then there's no uh you can go + + align:start position:0% +together then there's no uh you can go + + + align:start position:0% +together then there's no uh you can go +from anywhere to anywhere uh so you just + + align:start position:0% +from anywhere to anywhere uh so you just + + + align:start position:0% +from anywhere to anywhere uh so you just +add in some zeros here if you don't want + + align:start position:0% +add in some zeros here if you don't want + + + align:start position:0% +add in some zeros here if you don't want +there to be a connection from left to + + align:start position:0% +there to be a connection from left to + + + align:start position:0% +there to be a connection from left to +right so you can use that to delineate + + align:start position:0% +right so you can use that to delineate + + + align:start position:0% +right so you can use that to delineate +the boundary so this could actually do a + + align:start position:0% +the boundary so this could actually do a + + + align:start position:0% +the boundary so this could actually do a +subgraph of a grid graph even more + + align:start position:0% +subgraph of a grid graph even more + + + align:start position:0% +subgraph of a grid graph even more +special uh or you leave it clear if + + align:start position:0% +special uh or you leave it clear if + + + align:start position:0% +special uh or you leave it clear if +there's an edge so you get a picture + + align:start position:0% +there's an edge so you get a picture + + + align:start position:0% +there's an edge so you get a picture +like this in this case they're using + + align:start position:0% +like this in this case they're using + + + align:start position:0% +like this in this case they're using +these bunch of zeros to say well you you + + align:start position:0% +these bunch of zeros to say well you you + + + align:start position:0% +these bunch of zeros to say well you you +don't have to visit these pixels uh + + align:start position:0% +don't have to visit these pixels uh + + + align:start position:0% +don't have to visit these pixels uh +because they're just simulating a big + + align:start position:0% +because they're just simulating a big + + + align:start position:0% +because they're just simulating a big +Edge but we already have infrastructure + + align:start position:0% +Edge but we already have infrastructure + + + align:start position:0% +Edge but we already have infrastructure +to simulate edges we don't really need + + align:start position:0% +to simulate edges we don't really need + + + align:start position:0% +to simulate edges we don't really need +that okay so that's really easy + + align:start position:0% +that okay so that's really easy + + + align:start position:0% +that okay so that's really easy +proof uh I would say in general what you + + align:start position:0% +proof uh I would say in general what you + + + align:start position:0% +proof uh I would say in general what you +have to be careful about here is that + + align:start position:0% +have to be careful about here is that + + + align:start position:0% +have to be careful about here is that +edges are free because in hamiltonian + + align:start position:0% +edges are free because in hamiltonian + + + align:start position:0% +edges are free because in hamiltonian +cycle you're not supposed to pay for the + + align:start position:0% +cycle you're not supposed to pay for the + + + align:start position:0% +cycle you're not supposed to pay for the +edges you just have to visit every + + align:start position:0% +edges you just have to visit every + + + align:start position:0% +edges you just have to visit every +vertex uh but that's really easy in this + + align:start position:0% +vertex uh but that's really easy in this + + + align:start position:0% +vertex uh but that's really easy in this +kind of setup uh another Nick puzzle uh + + align:start position:0% +kind of setup uh another Nick puzzle uh + + + align:start position:0% +kind of setup uh another Nick puzzle uh +Hashi kako uh bridge building you have a + + align:start position:0% +Hashi kako uh bridge building you have a + + + align:start position:0% +Hashi kako uh bridge building you have a +bunch of dots in the plane each dot has + + align:start position:0% +bunch of dots in the plane each dot has + + + align:start position:0% +bunch of dots in the plane each dot has +a number on it uh specifying a degree + + align:start position:0% +a number on it uh specifying a degree + + + align:start position:0% +a number on it uh specifying a degree +request and your goal is to make a + + align:start position:0% +request and your goal is to make a + + + align:start position:0% +request and your goal is to make a +connected + + align:start position:0% +connected + + + align:start position:0% +connected +structure uh it looks like it's usually + + align:start position:0% +structure uh it looks like it's usually + + + align:start position:0% +structure uh it looks like it's usually +a tree but that's not part of the + + align:start position:0% +a tree but that's not part of the + + + align:start position:0% +a tree but that's not part of the +constraints uh where every vertex has + + align:start position:0% +constraints uh where every vertex has + + + align:start position:0% +constraints uh where every vertex has +that degree you can use multiple edges + + align:start position:0% +that degree you can use multiple edges + + + align:start position:0% +that degree you can use multiple edges +you can build multiple Bridges between + + align:start position:0% +you can build multiple Bridges between + + + align:start position:0% +you can build multiple Bridges between +the same two cities uh and so there's + + align:start position:0% +the same two cities uh and so there's + + + align:start position:0% +the same two cities uh and so there's +four here incident to that eight + + align:start position:0% +four here incident to that eight + + + align:start position:0% +four here incident to that eight +incident to that and everything's + + align:start position:0% +incident to that and everything's + + + align:start position:0% +incident to that and everything's +orthogonal you can only build horizontal + + align:start position:0% +orthogonal you can only build horizontal + + + align:start position:0% +orthogonal you can only build horizontal +vertical you can't build a bridge like + + align:start position:0% +vertical you can't build a bridge like + + + align:start position:0% +vertical you can't build a bridge like +this hard to make not allowed to make + + align:start position:0% +this hard to make not allowed to make + + + align:start position:0% +this hard to make not allowed to make +turns yeah think the standard posing you + + align:start position:0% +turns yeah think the standard posing you + + + align:start position:0% +turns yeah think the standard posing you +only get two parallel edges per pair ah + + align:start position:0% +only get two parallel edges per pair ah + + + align:start position:0% +only get two parallel edges per pair ah +and okay so also standard is that Max uh + + align:start position:0% +and okay so also standard is that Max uh + + + align:start position:0% +and okay so also standard is that Max uh +double edge no Triple Edge thank you I + + align:start position:0% +double edge no Triple Edge thank you I + + + align:start position:0% +double edge no Triple Edge thank you I +obviously haven't actually played um it + + align:start position:0% +obviously haven't actually played um it + + + align:start position:0% +obviously haven't actually played um it +won't matter in this reduction so here + + align:start position:0% +won't matter in this reduction so here + + + align:start position:0% +won't matter in this reduction so here +we are reducing from Hamilton in Grid + + align:start position:0% +we are reducing from Hamilton in Grid + + + align:start position:0% +we are reducing from Hamilton in Grid +graphs so these are edges that we might + + align:start position:0% +graphs so these are edges that we might + + + align:start position:0% +graphs so these are edges that we might +want to allow uh in general we're going + + align:start position:0% +want to allow uh in general we're going + + + align:start position:0% +want to allow uh in general we're going +to use these little ones to delineate + + align:start position:0% +to use these little ones to delineate + + + align:start position:0% +to use these little ones to delineate +the boundary it's just the same kind of + + align:start position:0% +the boundary it's just the same kind of + + + align:start position:0% +the boundary it's just the same kind of +trick we use uh here with ukian degree 3 + + align:start position:0% +trick we use uh here with ukian degree 3 + + + align:start position:0% +trick we use uh here with ukian degree 3 +MST we added the little dot just off to + + align:start position:0% +MST we added the little dot just off to + + + align:start position:0% +MST we added the little dot just off to +the side uh there it's not a metric + + align:start position:0% +the side uh there it's not a metric + + + align:start position:0% +the side uh there it's not a metric +problem here so we're just adding it one + + align:start position:0% +problem here so we're just adding it one + + + align:start position:0% +problem here so we're just adding it one +unit over that delineates the boundary + + align:start position:0% +unit over that delineates the boundary + + + align:start position:0% +unit over that delineates the boundary +that basically is forced to connect into + + align:start position:0% +that basically is forced to connect into + + + align:start position:0% +that basically is forced to connect into +the only uh neighbor you if you tried to + + align:start position:0% +the only uh neighbor you if you tried to + + + align:start position:0% +the only uh neighbor you if you tried to +do this kind of connection you'd end up + + align:start position:0% +do this kind of connection you'd end up + + + align:start position:0% +do this kind of connection you'd end up +being disconnected you just get sing + + align:start position:0% +being disconnected you just get sing + + + align:start position:0% +being disconnected you just get sing +single edge there because ones will only + + align:start position:0% +single edge there because ones will only + + + align:start position:0% +single edge there because ones will only +face ones so uh sorry the other + + align:start position:0% +face ones so uh sorry the other + + + align:start position:0% +face ones so uh sorry the other +constraint is uh you're not allowed of + + align:start position:0% +constraint is uh you're not allowed of + + + align:start position:0% +constraint is uh you're not allowed of +Crossing + + align:start position:0% +Crossing + + + align:start position:0% +Crossing +Bridges uh that won't matter here uh so + + align:start position:0% +Bridges uh that won't matter here uh so + + + align:start position:0% +Bridges uh that won't matter here uh so +we delineate the boundary at the ones + + align:start position:0% +we delineate the boundary at the ones + + + align:start position:0% +we delineate the boundary at the ones +and then every other vertex is going to + + align:start position:0% +and then every other vertex is going to + + + align:start position:0% +and then every other vertex is going to +have value two plus the number of + + align:start position:0% +have value two plus the number of + + + align:start position:0% +have value two plus the number of +boundary edges incident to it so here it + + align:start position:0% +boundary edges incident to it so here it + + + align:start position:0% +boundary edges incident to it so here it +happens to be four here it happens to be + + align:start position:0% +happens to be four here it happens to be + + + align:start position:0% +happens to be four here it happens to be +three so I could have gone like this + + align:start position:0% +three so I could have gone like this + + + align:start position:0% +three so I could have gone like this +that would have been fine but in this + + align:start position:0% +that would have been fine but in this + + + align:start position:0% +that would have been fine but in this +cycle I happened to go around that + + align:start position:0% +cycle I happened to go around that + + + align:start position:0% +cycle I happened to go around that +way okay that's representing this cycle + + align:start position:0% +way okay that's representing this cycle + + + align:start position:0% +way okay that's representing this cycle +so again very easy this shows you how + + align:start position:0% +so again very easy this shows you how + + + align:start position:0% +so again very easy this shows you how +useful it is once you have grid graphs + + align:start position:0% +useful it is once you have grid graphs + + + align:start position:0% +useful it is once you have grid graphs +you can do any problem on any grid + + align:start position:0% +you can do any problem on any grid + + + align:start position:0% +you can do any problem on any grid +pretty much that has any kind of tour + + align:start position:0% +pretty much that has any kind of tour + + + align:start position:0% +pretty much that has any kind of tour +like thing uh that will be hard using + + align:start position:0% +like thing uh that will be hard using + + + align:start position:0% +like thing uh that will be hard using +these reductions so that's why we + + align:start position:0% + + + + align:start position:0% + +care all right uh here's some practical + + align:start position:0% +care all right uh here's some practical + + + align:start position:0% +care all right uh here's some practical +motivation well I have a game here but + + align:start position:0% +motivation well I have a game here but + + + align:start position:0% +motivation well I have a game here but +suppose you're mowing your lawn and so + + align:start position:0% +suppose you're mowing your lawn and so + + + align:start position:0% +suppose you're mowing your lawn and so +usually a lawnmower has a circular + + align:start position:0% +usually a lawnmower has a circular + + + align:start position:0% +usually a lawnmower has a circular +cutting tool but uh in this game it + + align:start position:0% +cutting tool but uh in this game it + + + align:start position:0% +cutting tool but uh in this game it +happens to be a square cutting tool it's + + align:start position:0% +happens to be a square cutting tool it's + + + align:start position:0% +happens to be a square cutting tool it's +basically the same and you have some + + align:start position:0% +basically the same and you have some + + + align:start position:0% +basically the same and you have some +polygon with holes that you want to uh + + align:start position:0% +polygon with holes that you want to uh + + + align:start position:0% +polygon with holes that you want to uh +mow uh there's actually two versions of + + align:start position:0% +mow uh there's actually two versions of + + + align:start position:0% +mow uh there's actually two versions of +the + + align:start position:0% +the + + + align:start position:0% +the +problem + + align:start position:0% + + + + align:start position:0% + +uh and they were introduced by Aran Fe + + align:start position:0% +uh and they were introduced by Aran Fe + + + align:start position:0% +uh and they were introduced by Aran Fe +and Mitchell 2000 uh one's called lawn + + align:start position:0% +and Mitchell 2000 uh one's called lawn + + + align:start position:0% +and Mitchell 2000 uh one's called lawn +mowing + + align:start position:0% + + + + align:start position:0% + +so lawn mowing you're given a a polygon + + align:start position:0% +so lawn mowing you're given a a polygon + + + align:start position:0% +so lawn mowing you're given a a polygon +you you have to visit let's say if we're + + align:start position:0% +you you have to visit let's say if we're + + + align:start position:0% +you you have to visit let's say if we're +using a square cutter you have to visit + + align:start position:0% +using a square cutter you have to visit + + + align:start position:0% +using a square cutter you have to visit +every pixel of the polygon you have to + + align:start position:0% +every pixel of the polygon you have to + + + align:start position:0% +every pixel of the polygon you have to +visit the entire you're moving a square + + align:start position:0% +visit the entire you're moving a square + + + align:start position:0% +visit the entire you're moving a square +unit square around you've got to visit + + align:start position:0% +unit square around you've got to visit + + + align:start position:0% +unit square around you've got to visit +everything to cut the entire lawn but + + align:start position:0% +everything to cut the entire lawn but + + + align:start position:0% +everything to cut the entire lawn but +you're also allowed to leave the polygon + + align:start position:0% +you're also allowed to leave the polygon + + + align:start position:0% +you're also allowed to leave the polygon +because would for lawnmower you can go + + align:start position:0% +because would for lawnmower you can go + + + align:start position:0% +because would for lawnmower you can go +outside the grass you can go onto the + + align:start position:0% +outside the grass you can go onto the + + + align:start position:0% +outside the grass you can go onto the +pavement most lawnmowers that doesn't + + align:start position:0% +pavement most lawnmowers that doesn't + + + align:start position:0% +pavement most lawnmowers that doesn't +break it so that's called lawn mowing uh + + align:start position:0% +break it so that's called lawn mowing uh + + + align:start position:0% +break it so that's called lawn mowing uh +you can go outside if you want + + align:start position:0% + + + + align:start position:0% + +and the other problem is called + + align:start position:0% + + + + align:start position:0% + +milling and with Milling you can't go + + align:start position:0% + + + + align:start position:0% + +outside okay that video game is probably + + align:start position:0% +outside okay that video game is probably + + + align:start position:0% +outside okay that video game is probably +some hybrid between these two problems + + align:start position:0% +some hybrid between these two problems + + + align:start position:0% +some hybrid between these two problems +but both problems have been considered a + + align:start position:0% +but both problems have been considered a + + + align:start position:0% +but both problems have been considered a +lot especially from an approximation + + align:start position:0% +lot especially from an approximation + + + align:start position:0% +lot especially from an approximation +standpoint uh but just from a uh there + + align:start position:0% +standpoint uh but just from a uh there + + + align:start position:0% +standpoint uh but just from a uh there +are lots of situations where this kind + + align:start position:0% +are lots of situations where this kind + + + align:start position:0% +are lots of situations where this kind +of problem comes up suppose you're laser + + align:start position:0% +of problem comes up suppose you're laser + + + align:start position:0% +of problem comes up suppose you're laser +cutting uh this is one of the first + + align:start position:0% +cutting uh this is one of the first + + + align:start position:0% +cutting uh this is one of the first +laser cutter projects we did with George + + align:start position:0% +laser cutter projects we did with George + + + align:start position:0% +laser cutter projects we did with George +Hart back in 2003 + + align:start position:0% +Hart back in 2003 + + + align:start position:0% +Hart back in 2003 +um where cutting out these double + + align:start position:0% +um where cutting out these double + + + align:start position:0% +um where cutting out these double +two-headed salamanders like that and + + align:start position:0% +two-headed salamanders like that and + + + align:start position:0% +two-headed salamanders like that and +then assembling them if you've ever been + + align:start position:0% +then assembling them if you've ever been + + + align:start position:0% +then assembling them if you've ever been +to G6 in sta it's hanging there uh so + + align:start position:0% +to G6 in sta it's hanging there uh so + + + align:start position:0% +to G6 in sta it's hanging there uh so +you can think of this laser cutting + + align:start position:0% +you can think of this laser cutting + + + align:start position:0% +you can think of this laser cutting +problem is you have a lot of dots and + + align:start position:0% +problem is you have a lot of dots and + + + align:start position:0% +problem is you have a lot of dots and +you have to cut them all um that is + + align:start position:0% +you have to cut them all um that is + + + align:start position:0% +you have to cut them all um that is +pretty literally what happens to the + + align:start position:0% +pretty literally what happens to the + + + align:start position:0% +pretty literally what happens to the +laser cutter is pulsing with little dots + + align:start position:0% +laser cutter is pulsing with little dots + + + align:start position:0% +laser cutter is pulsing with little dots +um and in this case it looks pretty + + align:start position:0% +um and in this case it looks pretty + + + align:start position:0% +um and in this case it looks pretty +clear how to connect them together but + + align:start position:0% +clear how to connect them together but + + + align:start position:0% +clear how to connect them together but +uh if you're cutting many salamanders + + align:start position:0% +uh if you're cutting many salamanders + + + align:start position:0% +uh if you're cutting many salamanders +out of one sheet and you think of the + + align:start position:0% +out of one sheet and you think of the + + + align:start position:0% +out of one sheet and you think of the +salamanders is pretty small uh that's + + align:start position:0% +salamanders is pretty small uh that's + + + align:start position:0% +salamanders is pretty small uh that's +like a tsp problem or or really a + + align:start position:0% +like a tsp problem or or really a + + + align:start position:0% +like a tsp problem or or really a +Milling problem you have to visit all + + align:start position:0% +Milling problem you have to visit all + + + align:start position:0% +Milling problem you have to visit all +these things uh using the shortest uh + + align:start position:0% +these things uh using the shortest uh + + + align:start position:0% +these things uh using the shortest uh +it's really a lawn mowing problem so you + + align:start position:0% +it's really a lawn mowing problem so you + + + align:start position:0% +it's really a lawn mowing problem so you +can turn off the laser and you can move + + align:start position:0% +can turn off the laser and you can move + + + align:start position:0% +can turn off the laser and you can move +around to somewhere else that you don't + + align:start position:0% +around to somewhere else that you don't + + + align:start position:0% +around to somewhere else that you don't +want to + + align:start position:0% +want to + + + align:start position:0% +want to +visit uh 3D printing is like a lawn + + align:start position:0% +visit uh 3D printing is like a lawn + + + align:start position:0% +visit uh 3D printing is like a lawn +mowing problem in each layer so 3D + + align:start position:0% +mowing problem in each layer so 3D + + + align:start position:0% +mowing problem in each layer so 3D +printing is done by printing each layer + + align:start position:0% +printing is done by printing each layer + + + align:start position:0% +printing is done by printing each layer +and then stacking them up one at a time + + align:start position:0% +and then stacking them up one at a time + + + align:start position:0% +and then stacking them up one at a time +so in each layer you have to deposit + + align:start position:0% +so in each layer you have to deposit + + + align:start position:0% +so in each layer you have to deposit +material in fdm say we're additive + + align:start position:0% +material in fdm say we're additive + + + align:start position:0% +material in fdm say we're additive +printing uh you have to deposit material + + align:start position:0% +printing uh you have to deposit material + + + align:start position:0% +printing uh you have to deposit material +uh if you're doing laser curing same + + align:start position:0% +uh if you're doing laser curing same + + + align:start position:0% +uh if you're doing laser curing same +kind of thing how do you move the laser + + align:start position:0% +kind of thing how do you move the laser + + + align:start position:0% +kind of thing how do you move the laser +with the shortest amount of work uh it's + + align:start position:0% +with the shortest amount of work uh it's + + + align:start position:0% +with the shortest amount of work uh it's +called Milling I don't have an image for + + align:start position:0% +called Milling I don't have an image for + + + align:start position:0% +called Milling I don't have an image for +this because if you're doing NC Milling + + align:start position:0% +this because if you're doing NC Milling + + + align:start position:0% +this because if you're doing NC Milling +you have a drill and you're moving the + + align:start position:0% +you have a drill and you're moving the + + + align:start position:0% +you have a drill and you're moving the +drill around to cut out some shape you + + align:start position:0% +drill around to cut out some shape you + + + align:start position:0% +drill around to cut out some shape you +uh or to cut a + + align:start position:0% +uh or to cut a + + + align:start position:0% +uh or to cut a +region + + align:start position:0% +region + + + align:start position:0% +region +um you there you're not allowed to go + + align:start position:0% +um you there you're not allowed to go + + + align:start position:0% +um you there you're not allowed to go +outside the shape you want to cut + + align:start position:0% +outside the shape you want to cut + + + align:start position:0% +outside the shape you want to cut +because if you go outside you cut too + + align:start position:0% +because if you go outside you cut too + + + align:start position:0% +because if you go outside you cut too +much and you don't want to have to pay + + align:start position:0% +much and you don't want to have to pay + + + align:start position:0% +much and you don't want to have to pay +to retract there are other versions of + + align:start position:0% +to retract there are other versions of + + + align:start position:0% +to retract there are other versions of +the problem where you can retract the + + align:start position:0% +the problem where you can retract the + + + align:start position:0% +the problem where you can retract the +cut bit and so on uh so um of course we + + align:start position:0% +cut bit and so on uh so um of course we + + + align:start position:0% +cut bit and so on uh so um of course we +proved Milling is hard that is exactly + + align:start position:0% +proved Milling is hard that is exactly + + + align:start position:0% +proved Milling is hard that is exactly +the Hamilton see and grid graphs if + + align:start position:0% +the Hamilton see and grid graphs if + + + align:start position:0% +the Hamilton see and grid graphs if +you're not allowed to leave the region + + align:start position:0% +you're not allowed to leave the region + + + align:start position:0% +you're not allowed to leave the region +of course that also shows lawn mowing is + + align:start position:0% +of course that also shows lawn mowing is + + + align:start position:0% +of course that also shows lawn mowing is +hard because you never want to go + + align:start position:0% +hard because you never want to go + + + align:start position:0% +hard because you never want to go +outside the region one fun result is + + align:start position:0% +outside the region one fun result is + + + align:start position:0% +outside the region one fun result is +lawn mowing is hard even when you have + + align:start position:0% +lawn mowing is hard even when you have + + + align:start position:0% +lawn mowing is hard even when you have +no holes in your region so if you cut + + align:start position:0% +no holes in your region so if you cut + + + align:start position:0% +no holes in your region so if you cut +these little slits from a lawn mowing + + align:start position:0% +these little slits from a lawn mowing + + + align:start position:0% +these little slits from a lawn mowing +perspective it basically makes no + + align:start position:0% +perspective it basically makes no + + + align:start position:0% +perspective it basically makes no +difference because you can still go over + + align:start position:0% +difference because you can still go over + + + align:start position:0% +difference because you can still go over +it uh and it doesn't really save you + + align:start position:0% +it uh and it doesn't really save you + + + align:start position:0% +it uh and it doesn't really save you +anything to not have to cut that so + + align:start position:0% +anything to not have to cut that so + + + align:start position:0% +anything to not have to cut that so +lawnmowing is hard even without + + align:start position:0% +lawnmowing is hard even without + + + align:start position:0% +lawnmowing is hard even without +holes + + align:start position:0% +holes + + + align:start position:0% +holes +uh cool I have one more problem do you + + align:start position:0% +uh cool I have one more problem do you + + + align:start position:0% +uh cool I have one more problem do you +want to see + + align:start position:0% +want to see + + + align:start position:0% +want to see +it okay uh so here's uh sorry a brief + + align:start position:0% +it okay uh so here's uh sorry a brief + + + align:start position:0% +it okay uh so here's uh sorry a brief +warmup suppose you have a grid graph you + + align:start position:0% +warmup suppose you have a grid graph you + + + align:start position:0% +warmup suppose you have a grid graph you +rotate at 45° you can represent each of + + align:start position:0% +rotate at 45° you can represent each of + + + align:start position:0% +rotate at 45° you can represent each of +these vertices as a vertical segment if + + align:start position:0% +these vertices as a vertical segment if + + + align:start position:0% +these vertices as a vertical segment if +they're black parody or horizontal + + align:start position:0% +they're black parody or horizontal + + + align:start position:0% +they're black parody or horizontal +segment if they're white parody such + + align:start position:0% +segment if they're white parody such + + + align:start position:0% +segment if they're white parody such +that segments intersect if and only if + + align:start position:0% +that segments intersect if and only if + + + align:start position:0% +that segments intersect if and only if +there's an edge joining okay so these + + align:start position:0% +there's an edge joining okay so these + + + align:start position:0% +there's an edge joining okay so these +are unit orthogonal segments this is + + align:start position:0% +are unit orthogonal segments this is + + + align:start position:0% +are unit orthogonal segments this is +called an intersection graph where you + + align:start position:0% +called an intersection graph where you + + + align:start position:0% +called an intersection graph where you +the vertices are the objects and the + + align:start position:0% +the vertices are the objects and the + + + align:start position:0% +the vertices are the objects and the +edges are whether things + + align:start position:0% +edges are whether things + + + align:start position:0% +edges are whether things +intersect okay that I need that so + + align:start position:0% +intersect okay that I need that so + + + align:start position:0% +intersect okay that I need that so +hamiltonicity in these graphs is + + align:start position:0% +hamiltonicity in these graphs is + + + align:start position:0% +hamiltonicity in these graphs is +hard uh here's a problem called minimum + + align:start position:0% +hard uh here's a problem called minimum + + + align:start position:0% +hard uh here's a problem called minimum +turn Milling so a big issue for 3D + + align:start position:0% +turn Milling so a big issue for 3D + + + align:start position:0% +turn Milling so a big issue for 3D +printing uh for Milling usually when + + align:start position:0% +printing uh for Milling usually when + + + align:start position:0% +printing uh for Milling usually when +you're when you're cutting or you're + + align:start position:0% +you're when you're cutting or you're + + + align:start position:0% +you're when you're cutting or you're +depositing material you can move really + + align:start position:0% +depositing material you can move really + + + align:start position:0% +depositing material you can move really +fast in a straight line + + align:start position:0% +fast in a straight line + + + align:start position:0% +fast in a straight line +but when you need to make a turn you + + align:start position:0% +but when you need to make a turn you + + + align:start position:0% +but when you need to make a turn you +have to basically come to a stop and + + align:start position:0% +have to basically come to a stop and + + + align:start position:0% +have to basically come to a stop and +then speed up again so suppose you have + + align:start position:0% +then speed up again so suppose you have + + + align:start position:0% +then speed up again so suppose you have +infinite + + align:start position:0% +infinite + + + align:start position:0% +infinite +acceleration uh so to speak or close to + + align:start position:0% +acceleration uh so to speak or close to + + + align:start position:0% +acceleration uh so to speak or close to +infinite acceleration so once you're + + align:start position:0% +infinite acceleration so once you're + + + align:start position:0% +infinite acceleration so once you're +going straight you can go arbitrarily + + align:start position:0% +going straight you can go arbitrarily + + + align:start position:0% +going straight you can go arbitrarily +far for the same cost and what you + + align:start position:0% +far for the same cost and what you + + + align:start position:0% +far for the same cost and what you +really pay for is the slowing down and + + align:start position:0% +really pay for is the slowing down and + + + align:start position:0% +really pay for is the slowing down and +speeding back up at every corner so then + + align:start position:0% +speeding back up at every corner so then + + + align:start position:0% +speeding back up at every corner so then +you want to minimize the number of turns + + align:start position:0% +you want to minimize the number of turns + + + align:start position:0% +you want to minimize the number of turns +not the length this is one of my first + + align:start position:0% +not the length this is one of my first + + + align:start position:0% +not the length this is one of my first +hardness proofs that it was not about + + align:start position:0% +hardness proofs that it was not about + + + align:start position:0% +hardness proofs that it was not about +puzzles um I think the original paper + + align:start position:0% +puzzles um I think the original paper + + + align:start position:0% +puzzles um I think the original paper +was 2,000 then Journal version 2005 uh + + align:start position:0% +was 2,000 then Journal version 2005 uh + + + align:start position:0% +was 2,000 then Journal version 2005 uh +so suppose you have one of these + + align:start position:0% +so suppose you have one of these + + + align:start position:0% +so suppose you have one of these +rectangle intersection graphs what we're + + align:start position:0% +rectangle intersection graphs what we're + + + align:start position:0% +rectangle intersection graphs what we're +going to do is explode it replace each + + align:start position:0% +going to do is explode it replace each + + + align:start position:0% +going to do is explode it replace each +of these things with a a cycle and then + + align:start position:0% +of these things with a a cycle and then + + + align:start position:0% +of these things with a a cycle and then +thicken that cycle this is + + align:start position:0% +thicken that cycle this is + + + align:start position:0% +thicken that cycle this is +a thin grid graph not super thin maybe + + align:start position:0% +a thin grid graph not super thin maybe + + + align:start position:0% +a thin grid graph not super thin maybe +maybe super thin uh here it's super thin + + align:start position:0% +maybe super thin uh here it's super thin + + + align:start position:0% +maybe super thin uh here it's super thin +and here it's you have a little square + + align:start position:0% +and here it's you have a little square + + + align:start position:0% +and here it's you have a little square +that you're cutting with so each of + + align:start position:0% +that you're cutting with so each of + + + align:start position:0% +that you're cutting with so each of +these things you have to make four turns + + align:start position:0% +these things you have to make four turns + + + align:start position:0% +these things you have to make four turns +okay then also to go from one of these + + align:start position:0% +okay then also to go from one of these + + + align:start position:0% +okay then also to go from one of these +to one of these to go from one vertex to + + align:start position:0% +to one of these to go from one vertex to + + + align:start position:0% +to one of these to go from one vertex to +the next you need a turn so generally + + align:start position:0% +the next you need a turn so generally + + + align:start position:0% +the next you need a turn so generally +you're going to need five n turns in + + align:start position:0% +you're going to need five n turns in + + + align:start position:0% +you're going to need five n turns in +order to visit n of these original + + align:start position:0% +order to visit n of these original + + + align:start position:0% +order to visit n of these original +segments and you can do that if and only + + align:start position:0% +segments and you can do that if and only + + + align:start position:0% +segments and you can do that if and only +if there's a hamiltonian cycle in the + + align:start position:0% +if there's a hamiltonian cycle in the + + + align:start position:0% +if there's a hamiltonian cycle in the +original graph which was this picture uh + + align:start position:0% +original graph which was this picture uh + + + align:start position:0% +original graph which was this picture uh +basically if you come in one position uh + + align:start position:0% +basically if you come in one position uh + + + align:start position:0% +basically if you come in one position uh +so here's a uh cycle you're trying to or + + align:start position:0% +so here's a uh cycle you're trying to or + + + align:start position:0% +so here's a uh cycle you're trying to or +one of these um rectangles you want to + + align:start position:0% +one of these um rectangles you want to + + + align:start position:0% +one of these um rectangles you want to +visit you come in one place and you know + + align:start position:0% +visit you come in one place and you know + + + align:start position:0% +visit you come in one place and you know +you want leave on some other place so + + align:start position:0% +you want leave on some other place so + + + align:start position:0% +you want leave on some other place so +you double this Edge you're going to cut + + align:start position:0% +you double this Edge you're going to cut + + + align:start position:0% +you double this Edge you're going to cut +it twice that's allowed in this model + + align:start position:0% +it twice that's allowed in this model + + + align:start position:0% +it twice that's allowed in this model +and then you loop around and the number + + align:start position:0% +and then you loop around and the number + + + align:start position:0% +and then you loop around and the number +of turns here is exactly one to come in + + align:start position:0% +of turns here is exactly one to come in + + + align:start position:0% +of turns here is exactly one to come in +four to go around and then one to come + + align:start position:0% +four to go around and then one to come + + + align:start position:0% +four to go around and then one to come +out in general it's one per Edge in the + + align:start position:0% +out in general it's one per Edge in the + + + align:start position:0% +out in general it's one per Edge in the +cycle and four per vertex in the cycle + + align:start position:0% +cycle and four per vertex in the cycle + + + align:start position:0% +cycle and four per vertex in the cycle +so again uh hamiltonicity gives us what + + align:start position:0% +so again uh hamiltonicity gives us what + + + align:start position:0% +so again uh hamiltonicity gives us what +we want even when we're minimizing + + align:start position:0% +we want even when we're minimizing + + + align:start position:0% +we want even when we're minimizing +number of turns we can simulate that by + + align:start position:0% +number of turns we can simulate that by + + + align:start position:0% +number of turns we can simulate that by +counting vertices as turns basically + + align:start position:0% +counting vertices as turns basically + + + align:start position:0% +counting vertices as turns basically +and that's it for hamity \ No newline at end of file diff --git a/Q8p2q9GFBMk.txt b/Q8p2q9GFBMk.txt new file mode 100644 index 0000000000000000000000000000000000000000..50bc13e4d9b4c3dd2a6a5ab78202e77ed0b7ed98 --- /dev/null +++ b/Q8p2q9GFBMk.txt @@ -0,0 +1,7283 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +view additional materials from hundreds + + align:start position:0% +view additional materials from hundreds + + + align:start position:0% +view additional materials from hundreds +of MIT courses visit MIT open courseware + + align:start position:0% +of MIT courses visit MIT open courseware + + + align:start position:0% +of MIT courses visit MIT open courseware +at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu maybe a few of you were + + align:start position:0% +ocw.mit.edu maybe a few of you were + + + align:start position:0% +ocw.mit.edu maybe a few of you were +expecting a quiz today but I actually + + align:start position:0% +expecting a quiz today but I actually + + + align:start position:0% +expecting a quiz today but I actually +said on class on Friday that I wouldn't + + align:start position:0% +said on class on Friday that I wouldn't + + + align:start position:0% +said on class on Friday that I wouldn't +give the quiz this week + + align:start position:0% + + + + align:start position:0% + +so uh sticking with + + align:start position:0% +so uh sticking with + + + align:start position:0% +so uh sticking with +that I'm not giving it it was to be on + + align:start position:0% +that I'm not giving it it was to be on + + + align:start position:0% +that I'm not giving it it was to be on +the Wilson notes but + + align:start position:0% +the Wilson notes but + + + align:start position:0% +the Wilson notes but +uh I don't well if we can fit it in + + align:start position:0% +uh I don't well if we can fit it in + + + align:start position:0% +uh I don't well if we can fit it in +later we might but I want you to focus + + align:start position:0% +later we might but I want you to focus + + + align:start position:0% +later we might but I want you to focus +on your + + align:start position:0% + + + + align:start position:0% + +projects because the reading is not very + + align:start position:0% +projects because the reading is not very + + + align:start position:0% +projects because the reading is not very +heavy this + + align:start position:0% +heavy this + + + align:start position:0% +heavy this +week first is his chapter on cultural + + align:start position:0% +week first is his chapter on cultural + + + align:start position:0% +week first is his chapter on cultural +determinism so we'll talk about that + + align:start position:0% +determinism so we'll talk about that + + + align:start position:0% +determinism so we'll talk about that +today + + align:start position:0% +today + + + align:start position:0% +today +and then the remaining + + align:start position:0% +and then the remaining + + + align:start position:0% +and then the remaining +matters on Friday and + + align:start position:0% + + + + align:start position:0% + +Monday sorry the left projector the the + + align:start position:0% +Monday sorry the left projector the the + + + align:start position:0% +Monday sorry the left projector the the +bulb won't come + + align:start position:0% +bulb won't come + + + align:start position:0% +bulb won't come +on at least not from + + align:start position:0% + + + + align:start position:0% + +here this is + + align:start position:0% + + + + align:start position:0% + +how Alcock starts this chapter on + + align:start position:0% +how Alcock starts this chapter on + + + align:start position:0% +how Alcock starts this chapter on +cultural determin is in he quotes this + + align:start position:0% +cultural determin is in he quotes this + + + align:start position:0% +cultural determin is in he quotes this +soci sociology + + align:start position:0% +soci sociology + + + align:start position:0% +soci sociology +book human biology does nothing to + + align:start position:0% +book human biology does nothing to + + + align:start position:0% +book human biology does nothing to +structure human + + align:start position:0% +structure human + + + align:start position:0% +structure human +society and that's common + + align:start position:0% +society and that's common + + + align:start position:0% +society and that's common +um belief among sociologists and + + align:start position:0% +um belief among sociologists and + + + align:start position:0% +um belief among sociologists and +cultural anthropologists as we shall + + align:start position:0% +cultural anthropologists as we shall + + + align:start position:0% +cultural anthropologists as we shall +see they don't like social biology + + align:start position:0% +see they don't like social biology + + + align:start position:0% +see they don't like social biology +and some of that is still true U the + + align:start position:0% +and some of that is still true U the + + + align:start position:0% +and some of that is still true U the +arguments + + align:start position:0% +arguments + + + align:start position:0% +arguments +I think are more against biology in + + align:start position:0% +I think are more against biology in + + + align:start position:0% +I think are more against biology in +general if when it concerns Evolution + + align:start position:0% +general if when it concerns Evolution + + + align:start position:0% +general if when it concerns Evolution +applied to human + + align:start position:0% + + + + align:start position:0% + +beings + + align:start position:0% +beings + + + align:start position:0% +beings +Dennis in 95 called it Darwin's + + align:start position:0% +Dennis in 95 called it Darwin's + + + align:start position:0% +Dennis in 95 called it Darwin's +dangerous + + align:start position:0% + + + + align:start position:0% + +idea it's not just due to + + align:start position:0% +idea it's not just due to + + + align:start position:0% +idea it's not just due to +interpretations that are common among + + align:start position:0% +interpretations that are common among + + + align:start position:0% +interpretations that are common among +followers of religions it's + + align:start position:0% +followers of religions it's + + + align:start position:0% +followers of religions it's +uh also Al found in + + align:start position:0% +uh also Al found in + + + align:start position:0% +uh also Al found in +Academia in these groups and I mentioned + + align:start position:0% +Academia in these groups and I mentioned + + + align:start position:0% +Academia in these groups and I mentioned +and then Educators as + + align:start position:0% +and then Educators as + + + align:start position:0% +and then Educators as +well but there's certain errors that are + + align:start position:0% +well but there's certain errors that are + + + align:start position:0% +well but there's certain errors that are +repeated in their statements and one is + + align:start position:0% +repeated in their statements and one is + + + align:start position:0% +repeated in their statements and one is +you could say the error of the false + + align:start position:0% +you could say the error of the false + + + align:start position:0% +you could say the error of the false +dichotomy so what is the + + align:start position:0% +dichotomy so what is the + + + align:start position:0% +dichotomy so what is the +dichotomy that they're they're saying + + align:start position:0% +dichotomy that they're they're saying + + + align:start position:0% +dichotomy that they're they're saying +they favor one side not the other side + + align:start position:0% +they favor one side not the other side + + + align:start position:0% +they favor one side not the other side +the either culture or + + align:start position:0% +the either culture or + + + align:start position:0% +the either culture or +biology either learned or innate either + + align:start position:0% +biology either learned or innate either + + + align:start position:0% +biology either learned or innate either +nature or nurture we've talked about + + align:start position:0% +nature or nurture we've talked about + + + align:start position:0% +nature or nurture we've talked about +this before it's actually always both + + align:start position:0% +this before it's actually always both + + + align:start position:0% +this before it's actually always both +the same is true for culture biolog uh + + align:start position:0% +the same is true for culture biolog uh + + + align:start position:0% +the same is true for culture biolog uh +evolutionary influences and cultural + + align:start position:0% +evolutionary influences and cultural + + + align:start position:0% +evolutionary influences and cultural +influences on human behavior it's just a + + align:start position:0% +influences on human behavior it's just a + + + align:start position:0% +influences on human behavior it's just a +nature nurture + + align:start position:0% +nature nurture + + + align:start position:0% +nature nurture +issue they + + align:start position:0% +issue they + + + align:start position:0% +issue they +also confuse approximate and + + align:start position:0% +also confuse approximate and + + + align:start position:0% +also confuse approximate and +evolutionary or ultimate hypotheses + + align:start position:0% +evolutionary or ultimate hypotheses + + + align:start position:0% +evolutionary or ultimate hypotheses +that's also very common in their + + align:start position:0% + + + + align:start position:0% + +statements + + align:start position:0% +statements + + + align:start position:0% +statements +uh Alcock tells the story of Frank Boaz + + align:start position:0% +uh Alcock tells the story of Frank Boaz + + + align:start position:0% +uh Alcock tells the story of Frank Boaz +and his students Boaz + + align:start position:0% +and his students Boaz + + + align:start position:0% +and his students Boaz +was very well known as a he calls him + + align:start position:0% +was very well known as a he calls him + + + align:start position:0% +was very well known as a he calls him +the first modern cultural Anthropologist + + align:start position:0% +the first modern cultural Anthropologist + + + align:start position:0% +the first modern cultural Anthropologist +of + + align:start position:0% +of + + + align:start position:0% +of +note and he + + align:start position:0% +note and he + + + align:start position:0% +note and he +asserted what he his belief in the + + align:start position:0% +asserted what he his belief in the + + + align:start position:0% +asserted what he his belief in the +autonomy of culture from biology + + align:start position:0% +autonomy of culture from biology + + + align:start position:0% +autonomy of culture from biology +thereby according to elcock bringing the + + align:start position:0% +thereby according to elcock bringing the + + + align:start position:0% +thereby according to elcock bringing the +study of human behavior from + + align:start position:0% +study of human behavior from + + + align:start position:0% +study of human behavior from +evolutionary + + align:start position:0% +evolutionary + + + align:start position:0% +evolutionary +biology which had become admittedly + + align:start position:0% +biology which had become admittedly + + + align:start position:0% +biology which had become admittedly +tainted + + align:start position:0% +tainted + + + align:start position:0% +tainted +by many people who Associated it with + + align:start position:0% +by many people who Associated it with + + + align:start position:0% +by many people who Associated it with +racism social Darwinism and + + align:start position:0% + + + + align:start position:0% + +Eugenics they were used as you know from + + align:start position:0% +Eugenics they were used as you know from + + + align:start position:0% +Eugenics they were used as you know from +Reading earlier in the book used by + + align:start position:0% +Reading earlier in the book used by + + + align:start position:0% +Reading earlier in the book used by +critics of socio biology + + align:start position:0% + + + + align:start position:0% + +so Boaz in + + align:start position:0% +so Boaz in + + + align:start position:0% +so Boaz in +his at least according to his students + + align:start position:0% +his at least according to his students + + + align:start position:0% +his at least according to his students +uh uh promoted this idea that the + + align:start position:0% +uh uh promoted this idea that the + + + align:start position:0% +uh uh promoted this idea that the +cultural practices are Limitless in + + align:start position:0% +cultural practices are Limitless in + + + align:start position:0% +cultural practices are Limitless in +essentially arbitrary in nature and one + + align:start position:0% +essentially arbitrary in nature and one + + + align:start position:0% +essentially arbitrary in nature and one +of those students became very well known + + align:start position:0% +of those students became very well known + + + align:start position:0% +of those students became very well known +Margaret me I remember meeting a friend + + align:start position:0% +Margaret me I remember meeting a friend + + + align:start position:0% +Margaret me I remember meeting a friend +of mine in high + + align:start position:0% +of mine in high + + + align:start position:0% +of mine in high +school a girl who had mapped out her + + align:start position:0% +school a girl who had mapped out her + + + align:start position:0% +school a girl who had mapped out her +career based on the career of Margaret + + align:start position:0% +career based on the career of Margaret + + + align:start position:0% +career based on the career of Margaret +me she was going to become a cultural + + align:start position:0% +me she was going to become a cultural + + + align:start position:0% +me she was going to become a cultural +Anthropologist she was going to travel + + align:start position:0% +Anthropologist she was going to travel + + + align:start position:0% +Anthropologist she was going to travel +give lectures get paid for them and so + + align:start position:0% +give lectures get paid for them and so + + + align:start position:0% +give lectures get paid for them and so +on and so forth just like Margaret + + align:start position:0% +on and so forth just like Margaret + + + align:start position:0% +on and so forth just like Margaret +me + + align:start position:0% +me + + + align:start position:0% +me +uh I don't know what how that turned out + + align:start position:0% +uh I don't know what how that turned out + + + align:start position:0% +uh I don't know what how that turned out +but anyway this this was the book this + + align:start position:0% +but anyway this this was the book this + + + align:start position:0% +but anyway this this was the book this +was the book she Margaret me wrote this + + align:start position:0% +was the book she Margaret me wrote this + + + align:start position:0% +was the book she Margaret me wrote this +book entitled coming of age in Samoa was + + align:start position:0% +book entitled coming of age in Samoa was + + + align:start position:0% +book entitled coming of age in Samoa was +written in 28 or published in 28 + + align:start position:0% +written in 28 or published in 28 + + + align:start position:0% +written in 28 or published in 28 +was very widely quoted it certainly was + + align:start position:0% +was very widely quoted it certainly was + + + align:start position:0% +was very widely quoted it certainly was +well known up to about 1975 and I think + + align:start position:0% +well known up to about 1975 and I think + + + align:start position:0% +well known up to about 1975 and I think +it's declined somewhat since then and + + align:start position:0% +it's declined somewhat since then and + + + align:start position:0% +it's declined somewhat since then and +there are good reasons for that so let's + + align:start position:0% +there are good reasons for that so let's + + + align:start position:0% +there are good reasons for that so let's +look at why would people be interested + + align:start position:0% +look at why would people be interested + + + align:start position:0% +look at why would people be interested +in + + align:start position:0% +in + + + align:start position:0% +in +somoa because she claimed that the + + align:start position:0% +somoa because she claimed that the + + + align:start position:0% +somoa because she claimed that the +society there was very different from + + align:start position:0% +society there was very different from + + + align:start position:0% +society there was very different from +American + + align:start position:0% +American + + + align:start position:0% +American +society she said they + + align:start position:0% + + + + align:start position:0% + +were sexually free there was no conflict + + align:start position:0% +were sexually free there was no conflict + + + align:start position:0% +were sexually free there was no conflict +between kids and parents they were + + align:start position:0% +between kids and parents they were + + + align:start position:0% +between kids and parents they were +allowed to do whatever they wanted there + + align:start position:0% +allowed to do whatever they wanted there + + + align:start position:0% +allowed to do whatever they wanted there +was no rape and so on and so forth and + + align:start position:0% +was no rape and so on and so forth and + + + align:start position:0% +was no rape and so on and so forth and +one of these ID idilic + + align:start position:0% +one of these ID idilic + + + align:start position:0% +one of these ID idilic +societies + + align:start position:0% +societies + + + align:start position:0% +societies +well Derek + + align:start position:0% +well Derek + + + align:start position:0% +well Derek +Freeman went there and did she was only + + align:start position:0% +Freeman went there and did she was only + + + align:start position:0% +Freeman went there and did she was only +there for 12 + + align:start position:0% +there for 12 + + + align:start position:0% +there for 12 +weeks and interviewed a group of young + + align:start position:0% +weeks and interviewed a group of young + + + align:start position:0% +weeks and interviewed a group of young +women there that was the she quickly + + align:start position:0% +women there that was the she quickly + + + align:start position:0% +women there that was the she quickly +learned + + align:start position:0% +learned + + + align:start position:0% +learned +enough of the language she could + + align:start position:0% +enough of the language she could + + + align:start position:0% +enough of the language she could +communicate with + + align:start position:0% +communicate with + + + align:start position:0% +communicate with +them but that was the extent of her + + align:start position:0% +them but that was the extent of her + + + align:start position:0% +them but that was the extent of her +actual study + + align:start position:0% +actual study + + + align:start position:0% +actual study +well Derek Freeman went there much later + + align:start position:0% +well Derek Freeman went there much later + + + align:start position:0% +well Derek Freeman went there much later +and it led to a book in 1983 he he spent + + align:start position:0% +and it led to a book in 1983 he he spent + + + align:start position:0% +and it led to a book in 1983 he he spent +I don't remember how long but it was a + + align:start position:0% +I don't remember how long but it was a + + + align:start position:0% +I don't remember how long but it was a +couple of years I think uh and he wrote + + align:start position:0% +couple of years I think uh and he wrote + + + align:start position:0% +couple of years I think uh and he wrote +a book in 1983 very critical of me so + + align:start position:0% +a book in 1983 very critical of me so + + + align:start position:0% +a book in 1983 very critical of me so +let's just go through Margaret me's + + align:start position:0% +let's just go through Margaret me's + + + align:start position:0% +let's just go through Margaret me's +claims that turned out to be much too + + align:start position:0% +claims that turned out to be much too + + + align:start position:0% +claims that turned out to be much too +extreme so we want to know how did she + + align:start position:0% +extreme so we want to know how did she + + + align:start position:0% +extreme so we want to know how did she +come to believe those claims why did she + + align:start position:0% +come to believe those claims why did she + + + align:start position:0% +come to believe those claims why did she +make errors + + align:start position:0% +make errors + + + align:start position:0% +make errors +uh and we've already talked about Frank + + align:start position:0% +uh and we've already talked about Frank + + + align:start position:0% +uh and we've already talked about Frank +Boaz and what he believed and she was + + align:start position:0% +Boaz and what he believed and she was + + + align:start position:0% +Boaz and what he believed and she was +his student and she promoted those ideas + + align:start position:0% +his student and she promoted those ideas + + + align:start position:0% +his student and she promoted those ideas +in this + + align:start position:0% + + + + align:start position:0% + +book she claimed that Samoa Samoan + + align:start position:0% +book she claimed that Samoa Samoan + + + align:start position:0% +book she claimed that Samoa Samoan +Society is very + + align:start position:0% +Society is very + + + align:start position:0% +Society is very +different from our society having very + + align:start position:0% +different from our society having very + + + align:start position:0% +different from our society having very +relaxed attitudes towards premarital sex + + align:start position:0% +relaxed attitudes towards premarital sex + + + align:start position:0% +relaxed attitudes towards premarital sex +by young women uh and that used to be + + align:start position:0% +by young women uh and that used to be + + + align:start position:0% +by young women uh and that used to be +much stricter U at the time she wrote + + align:start position:0% +much stricter U at the time she wrote + + + align:start position:0% +much stricter U at the time she wrote +that book Far stricter than than it is + + align:start position:0% +that book Far stricter than than it is + + + align:start position:0% +that book Far stricter than than it is +now in modern American + + align:start position:0% +now in modern American + + + align:start position:0% +now in modern American +society he also claimed an absence of + + align:start position:0% +society he also claimed an absence of + + + align:start position:0% +society he also claimed an absence of +rape freedom from emotional turbulence + + align:start position:0% +rape freedom from emotional turbulence + + + align:start position:0% +rape freedom from emotional turbulence +during adolescence and remember these + + align:start position:0% +during adolescence and remember these + + + align:start position:0% +during adolescence and remember these +were adolescent girls who was + + align:start position:0% + + + + align:start position:0% + +interviewing so this is what she had + + align:start position:0% +interviewing so this is what she had + + + align:start position:0% +interviewing so this is what she had +done she at age + + align:start position:0% +done she at age + + + align:start position:0% +done she at age +23 because of being told by another + + align:start position:0% +23 because of being told by another + + + align:start position:0% +23 because of being told by another +cultural Anthropologist about Samo and + + align:start position:0% +cultural Anthropologist about Samo and + + + align:start position:0% +cultural Anthropologist about Samo and +Society she wanted to verify what they + + align:start position:0% +Society she wanted to verify what they + + + align:start position:0% +Society she wanted to verify what they +were + + align:start position:0% +were + + + align:start position:0% +were +believing + + align:start position:0% +believing + + + align:start position:0% +believing +uh so she based the study on + + align:start position:0% +uh so she based the study on + + + align:start position:0% +uh so she based the study on +interviewing 25 young + + align:start position:0% +interviewing 25 young + + + align:start position:0% +interviewing 25 young +women now those 25 women many of them + + align:start position:0% +women now those 25 women many of them + + + align:start position:0% +women now those 25 women many of them +most of them were still alive when Derek + + align:start position:0% +most of them were still alive when Derek + + + align:start position:0% +most of them were still alive when Derek +Freeman went there so he talked to the + + align:start position:0% +Freeman went there so he talked to the + + + align:start position:0% +Freeman went there so he talked to the +very same women when they were much + + align:start position:0% +very same women when they were much + + + align:start position:0% +very same women when they were much +older + + align:start position:0% + + + + align:start position:0% + +and as Freeman describes she didn't stay + + align:start position:0% +and as Freeman describes she didn't stay + + + align:start position:0% +and as Freeman describes she didn't stay +in Soma for really extensive + + align:start position:0% +in Soma for really extensive + + + align:start position:0% +in Soma for really extensive +observations she just believed what the + + align:start position:0% +observations she just believed what the + + + align:start position:0% +observations she just believed what the +girls told her and they were often + + align:start position:0% +girls told her and they were often + + + align:start position:0% +girls told her and they were often +kidding + + align:start position:0% +kidding + + + align:start position:0% +kidding +her she heard what she wanted to hear + + align:start position:0% +her she heard what she wanted to hear + + + align:start position:0% +her she heard what she wanted to hear +she didn't wasn't critical in her + + align:start position:0% + + + + align:start position:0% + +method and this belief of + + align:start position:0% +method and this belief of + + + align:start position:0% +method and this belief of +Boaz uh is what she wanted to promote + + align:start position:0% + + + + align:start position:0% + +they're certainly the same issues faced + + align:start position:0% +they're certainly the same issues faced + + + align:start position:0% +they're certainly the same issues faced +by + + align:start position:0% +by + + + align:start position:0% +by +sociobiologists since then when they + + align:start position:0% +sociobiologists since then when they + + + align:start position:0% +sociobiologists since then when they +have applied the ideas and methods to + + align:start position:0% +have applied the ideas and methods to + + + align:start position:0% +have applied the ideas and methods to +human that's what got EO Wilson we say + + align:start position:0% +human that's what got EO Wilson we say + + + align:start position:0% +human that's what got EO Wilson we say +in such + + align:start position:0% + + + + align:start position:0% + +trouble he was in trouble because he put + + align:start position:0% +trouble he was in trouble because he put + + + align:start position:0% +trouble he was in trouble because he put +a chapter on human society and the very + + align:start position:0% +a chapter on human society and the very + + + align:start position:0% +a chapter on human society and the very +last chapter of the book applying + + align:start position:0% +last chapter of the book applying + + + align:start position:0% +last chapter of the book applying +sociobiology ideas to Human + + align:start position:0% +sociobiology ideas to Human + + + align:start position:0% +sociobiology ideas to Human +to + + align:start position:0% +to + + + align:start position:0% +to +humans the I mean the bulk of the book + + align:start position:0% +humans the I mean the bulk of the book + + + align:start position:0% +humans the I mean the bulk of the book +is about animal + + align:start position:0% +is about animal + + + align:start position:0% +is about animal +behavior animal social behavior in + + align:start position:0% +behavior animal social behavior in + + + align:start position:0% +behavior animal social behavior in +particular so this is how I would + + align:start position:0% +particular so this is how I would + + + align:start position:0% +particular so this is how I would +summarize it all she tried to do a + + align:start position:0% +summarize it all she tried to do a + + + align:start position:0% +summarize it all she tried to do a +scientific study she was young + + align:start position:0% +scientific study she was young + + + align:start position:0% +scientific study she was young +inexperienced 23 years old she made big + + align:start position:0% +inexperienced 23 years old she made big + + + align:start position:0% +inexperienced 23 years old she made big +mistakes but her book became very + + align:start position:0% +mistakes but her book became very + + + align:start position:0% +mistakes but her book became very +popular and had a wide influence despite + + align:start position:0% +popular and had a wide influence despite + + + align:start position:0% +popular and had a wide influence despite +those + + align:start position:0% +those + + + align:start position:0% +those +erors and they didn't really be the + + align:start position:0% +erors and they didn't really be the + + + align:start position:0% +erors and they didn't really be the +erors didn't really become well known + + align:start position:0% +erors didn't really become well known + + + align:start position:0% +erors didn't really become well known +until and I don't think they're well + + align:start position:0% +until and I don't think they're well + + + align:start position:0% +until and I don't think they're well +known now except among + + align:start position:0% +known now except among + + + align:start position:0% +known now except among +academics U and that took many + + align:start position:0% + + + + align:start position:0% + +years + + align:start position:0% +years + + + align:start position:0% +years +so if we they obviously these cultural + + align:start position:0% +so if we they obviously these cultural + + + align:start position:0% +so if we they obviously these cultural +anthropologists had a blank slate view + + align:start position:0% +anthropologists had a blank slate view + + + align:start position:0% +anthropologists had a blank slate view +of human + + align:start position:0% +of human + + + align:start position:0% +of human +nature and we have we've talked about + + align:start position:0% +nature and we have we've talked about + + + align:start position:0% +nature and we have we've talked about +that conflicts with sociobiological + + align:start position:0% +that conflicts with sociobiological + + + align:start position:0% +that conflicts with sociobiological +views but what do Blank Slate views of + + align:start position:0% +views but what do Blank Slate views of + + + align:start position:0% +views but what do Blank Slate views of +human nature actually predict about + + align:start position:0% +human nature actually predict about + + + align:start position:0% +human nature actually predict about +social structure and + + align:start position:0% + + + + align:start position:0% + +practices and as we summarize that just + + align:start position:0% +practices and as we summarize that just + + + align:start position:0% +practices and as we summarize that just +note that it's it's + + align:start position:0% +note that it's it's + + + align:start position:0% +note that it's it's +easy to make these ideas believable + + align:start position:0% +easy to make these ideas believable + + + align:start position:0% +easy to make these ideas believable +about humans but not for Animals it's + + align:start position:0% +about humans but not for Animals it's + + + align:start position:0% +about humans but not for Animals it's +much more hard to make these predictions + + align:start position:0% +much more hard to make these predictions + + + align:start position:0% +much more hard to make these predictions +about + + align:start position:0% +about + + + align:start position:0% +about +animals + + align:start position:0% + + + + align:start position:0% + +there's two new things here about this + + align:start position:0% +there's two new things here about this + + + align:start position:0% +there's two new things here about this +whole discussion one is G's claim that + + align:start position:0% +whole discussion one is G's claim that + + + align:start position:0% +whole discussion one is G's claim that +uh bi he he was criticized by + + align:start position:0% +uh bi he he was criticized by + + + align:start position:0% +uh bi he he was criticized by +sociobiologists for talking so much + + align:start position:0% +sociobiologists for talking so much + + + align:start position:0% +sociobiologists for talking so much +about biological determinism that he + + align:start position:0% +about biological determinism that he + + + align:start position:0% +about biological determinism that he +changed it to biological + + align:start position:0% +changed it to biological + + + align:start position:0% +changed it to biological +potentiality so he claimed that a human + + align:start position:0% +potentiality so he claimed that a human + + + align:start position:0% +potentiality so he claimed that a human +has a brain capable of a full range of + + align:start position:0% +has a brain capable of a full range of + + + align:start position:0% +has a brain capable of a full range of +human behaviors and predisposed towards + + align:start position:0% +human behaviors and predisposed towards + + + align:start position:0% +human behaviors and predisposed towards +none + + align:start position:0% +none + + + align:start position:0% +none +he made that he was a biologist an + + align:start position:0% +he made that he was a biologist an + + + align:start position:0% +he made that he was a biologist an +evolutionary biologist writing regularly + + align:start position:0% +evolutionary biologist writing regularly + + + align:start position:0% +evolutionary biologist writing regularly +in the magazine natural history and he + + align:start position:0% +in the magazine natural history and he + + + align:start position:0% +in the magazine natural history and he +was very well + + align:start position:0% +was very well + + + align:start position:0% +was very well +known and he sort of becomes a Whipping + + align:start position:0% +known and he sort of becomes a Whipping + + + align:start position:0% +known and he sort of becomes a Whipping +Boy in alcock's + + align:start position:0% + + + + align:start position:0% + +book The problem is there was a lack of + + align:start position:0% +book The problem is there was a lack of + + + align:start position:0% +book The problem is there was a lack of +rigorous tests of the predictions of + + align:start position:0% +rigorous tests of the predictions of + + + align:start position:0% +rigorous tests of the predictions of +cultural + + align:start position:0% +cultural + + + align:start position:0% +cultural +determinism and + + align:start position:0% +determinism and + + + align:start position:0% +determinism and +elcock tries to suggest some predictions + + align:start position:0% +elcock tries to suggest some predictions + + + align:start position:0% +elcock tries to suggest some predictions +that the critic should be testing and + + align:start position:0% +that the critic should be testing and + + + align:start position:0% +that the critic should be testing and +given you where he does + + align:start position:0% +given you where he does + + + align:start position:0% +given you where he does +that he basically says human behavior + + align:start position:0% +that he basically says human behavior + + + align:start position:0% +that he basically says human behavior +should differ greatly and arbitrarily + + align:start position:0% +should differ greatly and arbitrarily + + + align:start position:0% +should differ greatly and arbitrarily +from society to society and he gives + + align:start position:0% +from society to society and he gives + + + align:start position:0% +from society to society and he gives +examples of that do you think that's + + align:start position:0% +examples of that do you think that's + + + align:start position:0% +examples of that do you think that's +true should societies differ + + align:start position:0% +true should societies differ + + + align:start position:0% +true should societies differ +arbitrarily well there got to be some + + align:start position:0% +arbitrarily well there got to be some + + + align:start position:0% +arbitrarily well there got to be some +constraints right but they claim there's + + align:start position:0% +constraints right but they claim there's + + + align:start position:0% +constraints right but they claim there's +no inheritance of + + align:start position:0% +no inheritance of + + + align:start position:0% +no inheritance of +behavior in humans only in animals or at + + align:start position:0% +behavior in humans only in animals or at + + + align:start position:0% +behavior in humans only in animals or at +least not you know when you start + + align:start position:0% +least not you know when you start + + + align:start position:0% +least not you know when you start +thinking about it does that mean they + + align:start position:0% +thinking about it does that mean they + + + align:start position:0% +thinking about it does that mean they +don't believe that we inherit the + + align:start position:0% +don't believe that we inherit the + + + align:start position:0% +don't believe that we inherit the +ability to + + align:start position:0% +ability to + + + align:start position:0% +ability to +walk I don't think + + align:start position:0% +walk I don't think + + + align:start position:0% +walk I don't think +so but actually most of them do believe + + align:start position:0% +so but actually most of them do believe + + + align:start position:0% +so but actually most of them do believe +we have to learn to + + align:start position:0% +we have to learn to + + + align:start position:0% +we have to learn to +walk as I pointed out a number of + + align:start position:0% +walk as I pointed out a number of + + + align:start position:0% +walk as I pointed out a number of +times even though it's actually a fixed + + align:start position:0% +times even though it's actually a fixed + + + align:start position:0% +times even though it's actually a fixed +action + + align:start position:0% +action + + + align:start position:0% +action +pattern uh as many other things are in + + align:start position:0% +pattern uh as many other things are in + + + align:start position:0% +pattern uh as many other things are in +human as well as in animal + + align:start position:0% + + + + align:start position:0% + +behavior so elcock tries to apply that + + align:start position:0% +behavior so elcock tries to apply that + + + align:start position:0% +behavior so elcock tries to apply that +and and uh I think it's pretty + + align:start position:0% +and and uh I think it's pretty + + + align:start position:0% +and and uh I think it's pretty +interesting when you actually make the + + align:start position:0% +interesting when you actually make the + + + align:start position:0% +interesting when you actually make the +predictions and you look from society to + + align:start position:0% +predictions and you look from society to + + + align:start position:0% +predictions and you look from society to +society and you find out that they + + align:start position:0% +society and you find out that they + + + align:start position:0% +society and you find out that they +don't there are wide differences but + + align:start position:0% +don't there are wide differences but + + + align:start position:0% +don't there are wide differences but +they don't they're not arbitrary random + + align:start position:0% +they don't they're not arbitrary random + + + align:start position:0% +they don't they're not arbitrary random +differences at + + align:start position:0% +differences at + + + align:start position:0% +differences at +all so read that and you will see + + align:start position:0% +all so read that and you will see + + + align:start position:0% +all so read that and you will see +exactly what I'm talking about I'm not + + align:start position:0% +exactly what I'm talking about I'm not + + + align:start position:0% +exactly what I'm talking about I'm not +going to go over them now it's very + + align:start position:0% +going to go over them now it's very + + + align:start position:0% +going to go over them now it's very +clear in alcock's book and uh you should + + align:start position:0% +clear in alcock's book and uh you should + + + align:start position:0% +clear in alcock's book and uh you should +be familiar with you know how difficult + + align:start position:0% +be familiar with you know how difficult + + + align:start position:0% +be familiar with you know how difficult +those predictions + + align:start position:0% +those predictions + + + align:start position:0% +those predictions +are + + align:start position:0% +are + + + align:start position:0% +are +to to to + + align:start position:0% +to to to + + + align:start position:0% +to to to +test I'm sorry they're not difficult to + + align:start position:0% +test I'm sorry they're not difficult to + + + align:start position:0% +test I'm sorry they're not difficult to +test they're difficult to verify any of + + align:start position:0% +test they're difficult to verify any of + + + align:start position:0% +test they're difficult to verify any of +them + + align:start position:0% +them + + + align:start position:0% +them +okay although we might not want to say + + align:start position:0% +okay although we might not want to say + + + align:start position:0% +okay although we might not want to say +there is completely arbitrary I don't + + align:start position:0% +there is completely arbitrary I don't + + + align:start position:0% +there is completely arbitrary I don't +know if any of them would claim that but + + align:start position:0% +know if any of them would claim that but + + + align:start position:0% +know if any of them would claim that but +the way they talk maybe it's partly in + + align:start position:0% +the way they talk maybe it's partly in + + + align:start position:0% +the way they talk maybe it's partly in +their the strength of their the vehement + + align:start position:0% +their the strength of their the vehement + + + align:start position:0% +their the strength of their the vehement +of their opposition to sociobiology that + + align:start position:0% +of their opposition to sociobiology that + + + align:start position:0% +of their opposition to sociobiology that +they make these strong claims + + align:start position:0% + + + + align:start position:0% + +but all + + align:start position:0% +but all + + + align:start position:0% +but all +right let's talk about male female + + align:start position:0% +right let's talk about male female + + + align:start position:0% +right let's talk about male female +attraction because this is something + + align:start position:0% +attraction because this is something + + + align:start position:0% +attraction because this is something +that sociobiologists have dealt with and + + align:start position:0% +that sociobiologists have dealt with and + + + align:start position:0% +that sociobiologists have dealt with and +dealt with it as you know in many + + align:start position:0% +dealt with it as you know in many + + + align:start position:0% +dealt with it as you know in many +animals we've talked about sexual + + align:start position:0% +animals we've talked about sexual + + + align:start position:0% +animals we've talked about sexual +selection we've shown examples of it + + align:start position:0% +selection we've shown examples of it + + + align:start position:0% +selection we've shown examples of it +from especially bird + + align:start position:0% +from especially bird + + + align:start position:0% +from especially bird +Behavior Uh there's a whole program on + + align:start position:0% +Behavior Uh there's a whole program on + + + align:start position:0% +Behavior Uh there's a whole program on +WGBH on love in animals and many many + + align:start position:0% +WGBH on love in animals and many many + + + align:start position:0% +WGBH on love in animals and many many +examples not just from + + align:start position:0% +examples not just from + + + align:start position:0% +examples not just from +Birds uh about things males will do to + + align:start position:0% +Birds uh about things males will do to + + + align:start position:0% +Birds uh about things males will do to +be chosen by females and a little bit on + + align:start position:0% +be chosen by females and a little bit on + + + align:start position:0% +be chosen by females and a little bit on +the other side though it's often it's + + align:start position:0% +the other side though it's often it's + + + align:start position:0% +the other side though it's often it's +more on that than on the uh mailmate + + align:start position:0% + + + + align:start position:0% + +choice I just want you to know when we + + align:start position:0% +choice I just want you to know when we + + + align:start position:0% +choice I just want you to know when we +go over this it's not what's + + align:start position:0% +go over this it's not what's + + + align:start position:0% +go over this it's not what's +fashionable that matches What Men + + align:start position:0% +fashionable that matches What Men + + + align:start position:0% +fashionable that matches What Men +actually prefer in a + + align:start position:0% +actually prefer in a + + + align:start position:0% +actually prefer in a +mate and yet what men actually prefer is + + align:start position:0% +mate and yet what men actually prefer is + + + align:start position:0% +mate and yet what men actually prefer is +the only thing of real interest to + + align:start position:0% +the only thing of real interest to + + + align:start position:0% +the only thing of real interest to +sociobiologist not what they say not + + align:start position:0% +sociobiologist not what they say not + + + align:start position:0% +sociobiologist not what they say not +what modern fashion dictates and so + + align:start position:0% +what modern fashion dictates and so + + + align:start position:0% +what modern fashion dictates and so +forth as a very easy example of that + + align:start position:0% +forth as a very easy example of that + + + align:start position:0% +forth as a very easy example of that +look at the difference + + align:start position:0% +look at the difference + + + align:start position:0% +look at the difference +between women that are pictured in + + align:start position:0% +between women that are pictured in + + + align:start position:0% +between women that are pictured in +fashion magazines and women that are + + align:start position:0% +fashion magazines and women that are + + + align:start position:0% +fashion magazines and women that are +pictured in the male pinup magazines or + + align:start position:0% +pictured in the male pinup magazines or + + + align:start position:0% +pictured in the male pinup magazines or +whatever you want to call + + align:start position:0% +whatever you want to call + + + align:start position:0% +whatever you want to call +them big + + align:start position:0% + + + + align:start position:0% + +differences okay + + align:start position:0% +differences okay + + + align:start position:0% +differences okay +uh + + align:start position:0% +uh + + + align:start position:0% +uh +also we should note that there are + + align:start position:0% +also we should note that there are + + + align:start position:0% +also we should note that there are +societal differences for example in the + + align:start position:0% +societal differences for example in the + + + align:start position:0% +societal differences for example in the +poorer Society + + align:start position:0% +poorer Society + + + align:start position:0% +poorer Society +women that are heavier that is a higher + + align:start position:0% +women that are heavier that is a higher + + + align:start position:0% +women that are heavier that is a higher +body mass index and we'll talk about + + align:start position:0% +body mass index and we'll talk about + + + align:start position:0% +body mass index and we'll talk about +that in a minute U the higher body mass + + align:start position:0% +that in a minute U the higher body mass + + + align:start position:0% +that in a minute U the higher body mass +index May indicate greater wealth and + + align:start position:0% +index May indicate greater wealth and + + + align:start position:0% +index May indicate greater wealth and +therefore be + + align:start position:0% +therefore be + + + align:start position:0% +therefore be +attractive when I first went to India I + + align:start position:0% +attractive when I first went to India I + + + align:start position:0% +attractive when I first went to India I +realized that at least at uh doesn't + + align:start position:0% +realized that at least at uh doesn't + + + align:start position:0% +realized that at least at uh doesn't +apply so much to + + align:start position:0% +apply so much to + + + align:start position:0% +apply so much to +the the very wealthy in India but if you + + align:start position:0% +the the very wealthy in India but if you + + + align:start position:0% +the the very wealthy in India but if you +deal with the bulk of the people + + align:start position:0% +deal with the bulk of the people + + + align:start position:0% +deal with the bulk of the people +um women that are heavier are often + + align:start position:0% +um women that are heavier are often + + + align:start position:0% +um women that are heavier are often +preferred uh because it indicates that + + align:start position:0% +preferred uh because it indicates that + + + align:start position:0% +preferred uh because it indicates that +they must have more + + align:start position:0% +they must have more + + + align:start position:0% +they must have more +resources you think that would apply + + align:start position:0% +resources you think that would apply + + + align:start position:0% +resources you think that would apply +even more to men men be heavier but they + + align:start position:0% +even more to men men be heavier but they + + + align:start position:0% +even more to men men be heavier but they +always talk about the + + align:start position:0% +always talk about the + + + align:start position:0% +always talk about the +women all + + align:start position:0% + + + + align:start position:0% + +right in Alcock this one I we'll take a + + align:start position:0% +right in Alcock this one I we'll take a + + + align:start position:0% +right in Alcock this one I we'll take a +look at since I didn't actually copy the + + align:start position:0% +look at since I didn't actually copy the + + + align:start position:0% +look at since I didn't actually copy the +table for the sleds but many of you have + + align:start position:0% +table for the sleds but many of you have + + + align:start position:0% +table for the sleds but many of you have +looked at it if you've read this chapter + + align:start position:0% +looked at it if you've read this chapter + + + align:start position:0% +looked at it if you've read this chapter +table 71 that's on page 138 he goes + + align:start position:0% +table 71 that's on page 138 he goes + + + align:start position:0% +table 71 that's on page 138 he goes +through attributes in women that men + + align:start position:0% +through attributes in women that men + + + align:start position:0% +through attributes in women that men +find attractive and what is their + + align:start position:0% +find attractive and what is their + + + align:start position:0% +find attractive and what is their +meaning what is their signal value what + + align:start position:0% +meaning what is their signal value what + + + align:start position:0% +meaning what is their signal value what +is that + + align:start position:0% +is that + + + align:start position:0% +is that +property of a woman's body + + align:start position:0% +property of a woman's body + + + align:start position:0% +property of a woman's body +signal and he says all the attributes + + align:start position:0% +signal and he says all the attributes + + + align:start position:0% +signal and he says all the attributes +listed indicate Health fertility sexual + + align:start position:0% +listed indicate Health fertility sexual + + + align:start position:0% +listed indicate Health fertility sexual +maturity and youth okay they're all + + align:start position:0% +maturity and youth okay they're all + + + align:start position:0% +maturity and youth okay they're all +together predictors of Lifetime + + align:start position:0% +together predictors of Lifetime + + + align:start position:0% +together predictors of Lifetime +reproductive potential and you must keep + + align:start position:0% +reproductive potential and you must keep + + + align:start position:0% +reproductive potential and you must keep +in mind when you look at these things + + align:start position:0% +in mind when you look at these things + + + align:start position:0% +in mind when you look at these things +that there's always a range there's + + align:start position:0% +that there's always a range there's + + + align:start position:0% +that there's always a range there's +always exceptions to the general rule + + align:start position:0% +always exceptions to the general rule + + + align:start position:0% +always exceptions to the general rule +sociobiological hypotheses are not about + + align:start position:0% +sociobiological hypotheses are not about + + + align:start position:0% +sociobiological hypotheses are not about +always and they're not disproved by + + align:start position:0% + + + + align:start position:0% + +sometimes so this first attribute is + + align:start position:0% +sometimes so this first attribute is + + + align:start position:0% +sometimes so this first attribute is +smoothed unblemished skin indicates + + align:start position:0% +smoothed unblemished skin indicates + + + align:start position:0% +smoothed unblemished skin indicates +youthfulness and good health + + align:start position:0% +youthfulness and good health + + + align:start position:0% +youthfulness and good health +and he lists he gives references for + + align:start position:0% +and he lists he gives references for + + + align:start position:0% +and he lists he gives references for +studies of that that have been done + + align:start position:0% +studies of that that have been done + + + align:start position:0% +studies of that that have been done +symmetrical faces and limbs indicates + + align:start position:0% +symmetrical faces and limbs indicates + + + align:start position:0% +symmetrical faces and limbs indicates +developmental stability good genes good + + align:start position:0% +developmental stability good genes good + + + align:start position:0% +developmental stability good genes good +nutritional experience during + + align:start position:0% +nutritional experience during + + + align:start position:0% +nutritional experience during +development then one he calls facial + + align:start position:0% +development then one he calls facial + + + align:start position:0% +development then one he calls facial +averageness Optimum optim indicates + + align:start position:0% +averageness Optimum optim indicates + + + align:start position:0% +averageness Optimum optim indicates +Optimum normal + + align:start position:0% +Optimum normal + + + align:start position:0% +Optimum normal +development and resistance to + + align:start position:0% +development and resistance to + + + align:start position:0% +development and resistance to +parasites + + align:start position:0% +parasites + + + align:start position:0% +parasites +prominent you know you don't think much + + align:start position:0% +prominent you know you don't think much + + + align:start position:0% +prominent you know you don't think much +we don't have that much trouble with + + align:start position:0% +we don't have that much trouble with + + + align:start position:0% +we don't have that much trouble with +parasites and but it's big problems for + + align:start position:0% +parasites and but it's big problems for + + + align:start position:0% +parasites and but it's big problems for +many groups humans groups and certainly + + align:start position:0% +many groups humans groups and certainly + + + align:start position:0% +many groups humans groups and certainly +was in our + + align:start position:0% +was in our + + + align:start position:0% +was in our +Evolution prominent cheekbones indicate + + align:start position:0% +Evolution prominent cheekbones indicate + + + align:start position:0% +Evolution prominent cheekbones indicate +sexual maturity cheekbones of mature + + align:start position:0% +sexual maturity cheekbones of mature + + + align:start position:0% +sexual maturity cheekbones of mature +women are quite different than when they + + align:start position:0% +women are quite different than when they + + + align:start position:0% +women are quite different than when they +were + + align:start position:0% +were + + + align:start position:0% +were +younger small chin small nose large eyes + + align:start position:0% +younger small chin small nose large eyes + + + align:start position:0% +younger small chin small nose large eyes +full lips indicates high estrogen levels + + align:start position:0% +full lips indicates high estrogen levels + + + align:start position:0% +full lips indicates high estrogen levels +during development and + + align:start position:0% +during development and + + + align:start position:0% +during development and +muths waste to hip ratio of + + align:start position:0% + + + + align:start position:0% + +0.7 indicates current high estrogen + + align:start position:0% +0.7 indicates current high estrogen + + + align:start position:0% +0.7 indicates current high estrogen +levels ample fat reserves in good health + + align:start position:0% +levels ample fat reserves in good health + + + align:start position:0% +levels ample fat reserves in good health +higher probability of becoming pregnant + + align:start position:0% +higher probability of becoming pregnant + + + align:start position:0% +higher probability of becoming pregnant +lower probability of early + + align:start position:0% + + + + align:start position:0% + +mortality there's been many studies of + + align:start position:0% +mortality there's been many studies of + + + align:start position:0% +mortality there's been many studies of +that and arguments about + + align:start position:0% +that and arguments about + + + align:start position:0% +that and arguments about +it but the average in what men prefer + + align:start position:0% +it but the average in what men prefer + + + align:start position:0% +it but the average in what men prefer +always comes out to be about 0.7 + + align:start position:0% + + + + align:start position:0% + +okay I remember reading one of the very + + align:start position:0% +okay I remember reading one of the very + + + align:start position:0% +okay I remember reading one of the very +early studies of that it was done by a + + align:start position:0% +early studies of that it was done by a + + + align:start position:0% +early studies of that it was done by a +woman from India uh very nice study + + align:start position:0% +woman from India uh very nice study + + + align:start position:0% +woman from India uh very nice study +where she made this whole science into a + + align:start position:0% +where she made this whole science into a + + + align:start position:0% +where she made this whole science into a +quantitative + + align:start position:0% +quantitative + + + align:start position:0% +quantitative +science large firm symmetrical breasts + + align:start position:0% +science large firm symmetrical breasts + + + align:start position:0% +science large firm symmetrical breasts +indicates developmental stability + + align:start position:0% +indicates developmental stability + + + align:start position:0% +indicates developmental stability +youthfulness and immune system + + align:start position:0% +youthfulness and immune system + + + align:start position:0% +youthfulness and immune system +competence in a body mass + + align:start position:0% +competence in a body mass + + + align:start position:0% +competence in a body mass +index in his table he says 20 to 24 the + + align:start position:0% +index in his table he says 20 to 24 the + + + align:start position:0% +index in his table he says 20 to 24 the +preferred range is actually 17 to 24 + + align:start position:0% +preferred range is actually 17 to 24 + + + align:start position:0% +preferred range is actually 17 to 24 +indicates high fertility and low + + align:start position:0% +indicates high fertility and low + + + align:start position:0% +indicates high fertility and low +mortality rates and you notice that is a + + align:start position:0% +mortality rates and you notice that is a + + + align:start position:0% +mortality rates and you notice that is a +big range 17 to + + align:start position:0% +big range 17 to + + + align:start position:0% +big range 17 to +24 um we'll talk a little more about + + align:start position:0% +24 um we'll talk a little more about + + + align:start position:0% +24 um we'll talk a little more about +this body mass + + align:start position:0% +this body mass + + + align:start position:0% +this body mass +index but + + align:start position:0% +index but + + + align:start position:0% +index but +uh right here I put I pulled a table out + + align:start position:0% +uh right here I put I pulled a table out + + + align:start position:0% +uh right here I put I pulled a table out +of + + align:start position:0% +of + + + align:start position:0% +of +Wikipedia + + align:start position:0% + + + + align:start position:0% + +uh + + align:start position:0% + + + + align:start position:0% + +I point out here at the top there's + + align:start position:0% +I point out here at the top there's + + + align:start position:0% +I point out here at the top there's +variability in measures of the relative + + align:start position:0% +variability in measures of the relative + + + align:start position:0% +variability in measures of the relative +importance + + align:start position:0% +importance + + + align:start position:0% +importance +of different factors especially in these + + align:start position:0% +of different factors especially in these + + + align:start position:0% +of different factors especially in these +two body mass index and the waist to hip + + align:start position:0% +two body mass index and the waist to hip + + + align:start position:0% +two body mass index and the waist to hip +ratio so we'll talk a little more about + + align:start position:0% +ratio so we'll talk a little more about + + + align:start position:0% +ratio so we'll talk a little more about +that but and he these are the class + + align:start position:0% +that but and he these are the class + + + align:start position:0% +that but and he these are the class +usual + + align:start position:0% +usual + + + align:start position:0% +usual +classifications from severely + + align:start position:0% +classifications from severely + + + align:start position:0% +classifications from severely +underweight and underweight to normal + + align:start position:0% +underweight and underweight to normal + + + align:start position:0% +underweight and underweight to normal +and then over and notice the normal + + align:start position:0% +and then over and notice the normal + + + align:start position:0% +and then over and notice the normal +ranges pretty big 185 to 25 how do you + + align:start position:0% +ranges pretty big 185 to 25 how do you + + + align:start position:0% +ranges pretty big 185 to 25 how do you +compute your body mass index since you + + align:start position:0% +compute your body mass index since you + + + align:start position:0% +compute your body mass index since you +Mar all be curious what your body mass + + align:start position:0% +Mar all be curious what your body mass + + + align:start position:0% +Mar all be curious what your body mass +is okay well notice it's it's in + + align:start position:0% +is okay well notice it's it's in + + + align:start position:0% +is okay well notice it's it's in +kilograms per meter squared meter of + + align:start position:0% +kilograms per meter squared meter of + + + align:start position:0% +kilograms per meter squared meter of +height + + align:start position:0% +height + + + align:start position:0% +height +okay so you have to convert your weight + + align:start position:0% +okay so you have to convert your weight + + + align:start position:0% +okay so you have to convert your weight +in pounds to kilogram to get this + + align:start position:0% +in pounds to kilogram to get this + + + align:start position:0% +in pounds to kilogram to get this +measure con convert your height + + align:start position:0% +measure con convert your height + + + align:start position:0% +measure con convert your height +to + + align:start position:0% +to + + + align:start position:0% +to +uh to + + align:start position:0% +uh to + + + align:start position:0% +uh to +meters and then you come out with these + + align:start position:0% +meters and then you come out with these + + + align:start position:0% +meters and then you come out with these +numbers you know and most of you I'm + + align:start position:0% +numbers you know and most of you I'm + + + align:start position:0% +numbers you know and most of you I'm +sure will fall in this range 18 and half + + align:start position:0% +sure will fall in this range 18 and half + + + align:start position:0% +sure will fall in this range 18 and half +to + + align:start position:0% + + + + align:start position:0% + +25 and yes I'm not underweight I'm + + align:start position:0% +25 and yes I'm not underweight I'm + + + align:start position:0% +25 and yes I'm not underweight I'm +actually in this range I'm at the low + + align:start position:0% +actually in this range I'm at the low + + + align:start position:0% +actually in this range I'm at the low +end okay and + + align:start position:0% +end okay and + + + align:start position:0% +end okay and +U and then notice all these categories + + align:start position:0% +U and then notice all these categories + + + align:start position:0% +U and then notice all these categories +for being over overweight overweight + + align:start position:0% +for being over overweight overweight + + + align:start position:0% +for being over overweight overweight +obese class one obese class 2 severely + + align:start position:0% +obese class one obese class 2 severely + + + align:start position:0% +obese class one obese class 2 severely +obese morbidly obese super obese and + + align:start position:0% +obese morbidly obese super obese and + + + align:start position:0% +obese morbidly obese super obese and +Hyper + + align:start position:0% +Hyper + + + align:start position:0% +Hyper +obese and notice these are the + + align:start position:0% +obese and notice these are the + + + align:start position:0% +obese and notice these are the +weights + + align:start position:0% +weights + + + align:start position:0% +weights +of someone + + align:start position:0% +of someone + + + align:start position:0% +of someone +with that's U 5' 11 1.8 + + align:start position:0% +with that's U 5' 11 1.8 + + + align:start position:0% +with that's U 5' 11 1.8 +m okay so if they're + + align:start position:0% +m okay so if they're + + + align:start position:0% +m okay so if they're +5'11 okay very tall woman + + align:start position:0% +5'11 okay very tall woman + + + align:start position:0% +5'11 okay very tall woman +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +an average man these are the weights + + align:start position:0% +an average man these are the weights + + + align:start position:0% +an average man these are the weights +they have to be to have that body mass + + align:start position:0% +they have to be to have that body mass + + + align:start position:0% +they have to be to have that body mass +index and the males always prefer as I + + align:start position:0% +index and the males always prefer as I + + + align:start position:0% +index and the males always prefer as I +pointed out before 17 to + + align:start position:0% +pointed out before 17 to + + + align:start position:0% +pointed out before 17 to +24 okay so they + + align:start position:0% +24 okay so they + + + align:start position:0% +24 okay so they +prefer women to be from at the top end + + align:start position:0% +prefer women to be from at the top end + + + align:start position:0% +prefer women to be from at the top end +of the underweight range uh to near the + + align:start position:0% +of the underweight range uh to near the + + + align:start position:0% +of the underweight range uh to near the +top of + + align:start position:0% +top of + + + align:start position:0% +top of +normal + + align:start position:0% + + + + align:start position:0% + +okay so then he cites this British study + + align:start position:0% +okay so then he cites this British study + + + align:start position:0% +okay so then he cites this British study +1998 of preferences shown by British + + align:start position:0% +1998 of preferences shown by British + + + align:start position:0% +1998 of preferences shown by British +male + + align:start position:0% +male + + + align:start position:0% +male +undergraduates this is the title Optimum + + align:start position:0% +undergraduates this is the title Optimum + + + align:start position:0% +undergraduates this is the title Optimum +body mass index and maximum sexual + + align:start position:0% + + + + align:start position:0% + +attractiveness and they claim and this + + align:start position:0% +attractiveness and they claim and this + + + align:start position:0% +attractiveness and they claim and this +is shows you the controversy because + + align:start position:0% +is shows you the controversy because + + + align:start position:0% +is shows you the controversy because +there's been many studies of waste to + + align:start position:0% +there's been many studies of waste to + + + align:start position:0% +there's been many studies of waste to +hip ratios the big factor for + + align:start position:0% +hip ratios the big factor for + + + align:start position:0% +hip ratios the big factor for +attractiveness they found that the BMI + + align:start position:0% +attractiveness they found that the BMI + + + align:start position:0% +attractiveness they found that the BMI +was a much better predictable in the + + align:start position:0% +was a much better predictable in the + + + align:start position:0% +was a much better predictable in the +ways to hip + + align:start position:0% +ways to hip + + + align:start position:0% +ways to hip +ratio even though other studies haven't + + align:start position:0% +ratio even though other studies haven't + + + align:start position:0% +ratio even though other studies haven't +shown such a difference in fact the + + align:start position:0% +shown such a difference in fact the + + + align:start position:0% +shown such a difference in fact the +ratio's been often been reported to be + + align:start position:0% +ratio's been often been reported to be + + + align:start position:0% +ratio's been often been reported to be +the most important so I'm going to go + + align:start position:0% +the most important so I'm going to go + + + align:start position:0% +the most important so I'm going to go +through one of those interesting studies + + align:start position:0% +through one of those interesting studies + + + align:start position:0% +through one of those interesting studies +next I think both factors there's plenty + + align:start position:0% +next I think both factors there's plenty + + + align:start position:0% +next I think both factors there's plenty +of evidence that both factors are + + align:start position:0% +of evidence that both factors are + + + align:start position:0% +of evidence that both factors are +important but in their study the the + + align:start position:0% +important but in their study the the + + + align:start position:0% +important but in their study the the +range was 17 to + + align:start position:0% +range was 17 to + + + align:start position:0% +range was 17 to +24 uh and I point out the numbers there + + align:start position:0% +24 uh and I point out the numbers there + + + align:start position:0% +24 uh and I point out the numbers there +for both those both those type of + + align:start position:0% +for both those both those type of + + + align:start position:0% +for both those both those type of +values but there are + + align:start position:0% +values but there are + + + align:start position:0% +values but there are +exceptions and one is this the group of + + align:start position:0% +exceptions and one is this the group of + + + align:start position:0% +exceptions and one is this the group of +yomi okay South American + + align:start position:0% +yomi okay South American + + + align:start position:0% +yomi okay South American +tribe U was found that they tend to + + align:start position:0% +tribe U was found that they tend to + + + align:start position:0% +tribe U was found that they tend to +prefer females with a figure that's + + align:start position:0% +prefer females with a figure that's + + + align:start position:0% +prefer females with a figure that's +heavier with a larger waste to hip + + align:start position:0% +heavier with a larger waste to hip + + + align:start position:0% +heavier with a larger waste to hip +ratio than pre than what is preferred by + + align:start position:0% +ratio than pre than what is preferred by + + + align:start position:0% +ratio than pre than what is preferred by +most men and and most in what we call + + align:start position:0% +most men and and most in what we call + + + align:start position:0% +most men and and most in what we call +Advanced + + align:start position:0% +Advanced + + + align:start position:0% +Advanced +cultures Advanced technically + + align:start position:0% +cultures Advanced technically + + + align:start position:0% +cultures Advanced technically +educationally so forth okay + + align:start position:0% +educationally so forth okay + + + align:start position:0% +educationally so forth okay +and I didn't bring the pictures they + + align:start position:0% +and I didn't bring the pictures they + + + align:start position:0% +and I didn't bring the pictures they +show silhouettes of the kind of women + + align:start position:0% +show silhouettes of the kind of women + + + align:start position:0% +show silhouettes of the kind of women +they they were basically these men in + + align:start position:0% +they they were basically these men in + + + align:start position:0% +they they were basically these men in +the test were shown little drawings of + + align:start position:0% +the test were shown little drawings of + + + align:start position:0% +the test were shown little drawings of +women uh sort of front view mostly front + + align:start position:0% +women uh sort of front view mostly front + + + align:start position:0% +women uh sort of front view mostly front +view so you can see their shape and they + + align:start position:0% +view so you can see their shape and they + + + align:start position:0% +view so you can see their shape and they +chose the heavy slightly heavier than + + align:start position:0% +chose the heavy slightly heavier than + + + align:start position:0% +chose the heavy slightly heavier than +the what people in USA or Europe would + + align:start position:0% +the what people in USA or Europe would + + + align:start position:0% +the what people in USA or Europe would +choose So He suggests I think his + + align:start position:0% +choose So He suggests I think his + + + align:start position:0% +choose So He suggests I think his +argument it's a little bit fuzzy but it + + align:start position:0% +argument it's a little bit fuzzy but it + + + align:start position:0% +argument it's a little bit fuzzy but it +and it hasn't been fully tested + + align:start position:0% +and it hasn't been fully tested + + + align:start position:0% +and it hasn't been fully tested +but he points out that obesity was all + + align:start position:0% +but he points out that obesity was all + + + align:start position:0% +but he points out that obesity was all +but impossible in pre-colonial Amar + + align:start position:0% +but impossible in pre-colonial Amar + + + align:start position:0% +but impossible in pre-colonial Amar +Indian groups these were American an + + align:start position:0% +Indian groups these were American an + + + align:start position:0% +Indian groups these were American an +American Indian group in South America + + align:start position:0% +American Indian group in South America + + + align:start position:0% +American Indian group in South America +uh being underweight was probably more + + align:start position:0% +uh being underweight was probably more + + + align:start position:0% +uh being underweight was probably more +common and if a woman was slightly + + align:start position:0% +common and if a woman was slightly + + + align:start position:0% +common and if a woman was slightly +overweight + + align:start position:0% +overweight + + + align:start position:0% +overweight +He suggests that there was a greater + + align:start position:0% +He suggests that there was a greater + + + align:start position:0% +He suggests that there was a greater +probability of her being + + align:start position:0% +probability of her being + + + align:start position:0% +probability of her being +fertile and also the probability would + + align:start position:0% +fertile and also the probability would + + + align:start position:0% +fertile and also the probability would +be greater that she doesn't have a + + align:start position:0% +be greater that she doesn't have a + + + align:start position:0% +be greater that she doesn't have a +problem with parasites which are common + + align:start position:0% +problem with parasites which are common + + + align:start position:0% +problem with parasites which are common +down in + + align:start position:0% +down in + + + align:start position:0% +down in +there uh and with their living + + align:start position:0% +there uh and with their living + + + align:start position:0% +there uh and with their living +style and of course that suggestion + + align:start position:0% +style and of course that suggestion + + + align:start position:0% +style and of course that suggestion +should apply to other groups that should + + align:start position:0% +should apply to other groups that should + + + align:start position:0% +should apply to other groups that should +be more + + align:start position:0% +be more + + + align:start position:0% +be more +tested + + align:start position:0% + + + + align:start position:0% + +uh and it should at least be true for + + align:start position:0% +uh and it should at least be true for + + + align:start position:0% +uh and it should at least be true for +groups that have been isolated from + + align:start position:0% +groups that have been isolated from + + + align:start position:0% +groups that have been isolated from +Modern + + align:start position:0% + + + + align:start position:0% + +societies we don't know he's probably + + align:start position:0% +societies we don't know he's probably + + + align:start position:0% +societies we don't know he's probably +right about this but you know you need + + align:start position:0% +right about this but you know you need + + + align:start position:0% +right about this but you know you need +to test any of these + + align:start position:0% +to test any of these + + + align:start position:0% +to test any of these +ideas and but you could also just say + + align:start position:0% +ideas and but you could also just say + + + align:start position:0% +ideas and but you could also just say +well okay one one exception doesn't + + align:start position:0% +well okay one one exception doesn't + + + align:start position:0% +well okay one one exception doesn't +disprove the general finding and even + + align:start position:0% +disprove the general finding and even + + + align:start position:0% +disprove the general finding and even +though that's true when you get a + + align:start position:0% +though that's true when you get a + + + align:start position:0% +though that's true when you get a +consistent finding like that in one + + align:start position:0% +consistent finding like that in one + + + align:start position:0% +consistent finding like that in one +Society there's got to be some reason + + align:start position:0% +Society there's got to be some reason + + + align:start position:0% +Society there's got to be some reason +for it and so it's worthy of more + + align:start position:0% +for it and so it's worthy of more + + + align:start position:0% +for it and so it's worthy of more +investigation + + align:start position:0% +investigation + + + align:start position:0% +investigation +but not just with the yomi but with + + align:start position:0% +but not just with the yomi but with + + + align:start position:0% +but not just with the yomi but with +other groups where similar conditions + + align:start position:0% + + + + align:start position:0% + +apply okay now this is a + + align:start position:0% +apply okay now this is a + + + align:start position:0% +apply okay now this is a +study uh where they paid attention to + + align:start position:0% +study uh where they paid attention to + + + align:start position:0% +study uh where they paid attention to +both of these + + align:start position:0% +both of these + + + align:start position:0% +both of these +measures this is the article male + + align:start position:0% +measures this is the article male + + + align:start position:0% +measures this is the article male +preferences for female waist to hip + + align:start position:0% +preferences for female waist to hip + + + align:start position:0% +preferences for female waist to hip +ratio and body mass index in the + + align:start position:0% +ratio and body mass index in the + + + align:start position:0% +ratio and body mass index in the +highlands of Papua New + + align:start position:0% + + + + align:start position:0% + +Guinea + + align:start position:0% +Guinea + + + align:start position:0% +Guinea +it was published in the American Journal + + align:start position:0% +it was published in the American Journal + + + align:start position:0% +it was published in the American Journal +of physical anthropology a few years + + align:start position:0% + + + + align:start position:0% + +ago they were using 100 men in three + + align:start position:0% +ago they were using 100 men in three + + + align:start position:0% +ago they were using 100 men in three +villages in this remote + + align:start position:0% +villages in this remote + + + align:start position:0% +villages in this remote +region they were asked to judge + + align:start position:0% +region they were asked to judge + + + align:start position:0% +region they were asked to judge +attractiveness of women who had + + align:start position:0% +attractiveness of women who had + + + align:start position:0% +attractiveness of women who had +undergone micrograph surgery to reduce + + align:start position:0% +undergone micrograph surgery to reduce + + + align:start position:0% +undergone micrograph surgery to reduce +their waste to hip ratio they'd + + align:start position:0% +their waste to hip ratio they'd + + + align:start position:0% +their waste to hip ratio they'd +undergone a kind of plastic + + align:start position:0% +undergone a kind of plastic + + + align:start position:0% +undergone a kind of plastic +surgery + + align:start position:0% +surgery + + + align:start position:0% +surgery +so what they do is they take the fatty + + align:start position:0% +so what they do is they take the fatty + + + align:start position:0% +so what they do is they take the fatty +tissue the adapost tissue from the waist + + align:start position:0% +tissue the adapost tissue from the waist + + + align:start position:0% +tissue the adapost tissue from the waist +and reshape the buttocks with it so the + + align:start position:0% +and reshape the buttocks with it so the + + + align:start position:0% +and reshape the buttocks with it so the +weight the average weight anyway of + + align:start position:0% +weight the average weight anyway of + + + align:start position:0% +weight the average weight anyway of +these women doesn't change + + align:start position:0% +these women doesn't change + + + align:start position:0% +these women doesn't change +much but their shape + + align:start position:0% + + + + align:start position:0% + +changes they get more of an hourglass + + align:start position:0% +changes they get more of an hourglass + + + align:start position:0% +changes they get more of an hourglass +figure and the men consistently chose + + align:start position:0% +figure and the men consistently chose + + + align:start position:0% +figure and the men consistently chose +postoperative photographs as being more + + align:start position:0% +postoperative photographs as being more + + + align:start position:0% +postoperative photographs as being more +attractive than pre-operative + + align:start position:0% +attractive than pre-operative + + + align:start position:0% +attractive than pre-operative +photographs of the same women + + align:start position:0% + + + + align:start position:0% + +and it didn't seem to be the body mass + + align:start position:0% +and it didn't seem to be the body mass + + + align:start position:0% +and it didn't seem to be the body mass +index that made a difference these These + + align:start position:0% +index that made a difference these These + + + align:start position:0% +index that made a difference these These +are the actual numbers from the study so + + align:start position:0% +are the actual numbers from the study so + + + align:start position:0% +are the actual numbers from the study so +and + + align:start position:0% +and + + + align:start position:0% +and +uh the were they did it twice these are + + align:start position:0% +uh the were they did it twice these are + + + align:start position:0% +uh the were they did it twice these are +the two groups of women undergoing this + + align:start position:0% +the two groups of women undergoing this + + + align:start position:0% +the two groups of women undergoing this +surgery uh this is these + + align:start position:0% +surgery uh this is these + + + align:start position:0% +surgery uh this is these +are G gives the patients uh ethnicity + + align:start position:0% +are G gives the patients uh ethnicity + + + align:start position:0% +are G gives the patients uh ethnicity +and you can see that + + align:start position:0% + + + + align:start position:0% + +varied + + align:start position:0% +varied + + + align:start position:0% +varied +and the in this group + + align:start position:0% + + + + align:start position:0% + +uh you can see that the body mass index + + align:start position:0% +uh you can see that the body mass index + + + align:start position:0% +uh you can see that the body mass index +was not change one group they were + + align:start position:0% +was not change one group they were + + + align:start position:0% +was not change one group they were +changing more the other one group + + align:start position:0% +changing more the other one group + + + align:start position:0% +changing more the other one group +actually went up a little bit the other + + align:start position:0% +actually went up a little bit the other + + + align:start position:0% +actually went up a little bit the other +group went down a little bit the body + + align:start position:0% +group went down a little bit the body + + + align:start position:0% +group went down a little bit the body +mass index but the waste hip ratios that + + align:start position:0% +mass index but the waste hip ratios that + + + align:start position:0% +mass index but the waste hip ratios that +you can see would + + align:start position:0% +you can see would + + + align:start position:0% +you can see would +consistently uh + + align:start position:0% + + + + align:start position:0% + +reduced + + align:start position:0% + + + + align:start position:0% + +all right so that was the data they had + + align:start position:0% +all right so that was the data they had + + + align:start position:0% +all right so that was the data they had +and they the men were tested on + + align:start position:0% +and they the men were tested on + + + align:start position:0% +and they the men were tested on +photographs these were the the nature of + + align:start position:0% +photographs these were the the nature of + + + align:start position:0% +photographs these were the the nature of +the photographs so here's a preop here's + + align:start position:0% +the photographs so here's a preop here's + + + align:start position:0% +the photographs so here's a preop here's +postop and this is the oblike view preop + + align:start position:0% +postop and this is the oblike view preop + + + align:start position:0% +postop and this is the oblike view preop +and postop so it shows what the surgeons + + align:start position:0% +and postop so it shows what the surgeons + + + align:start position:0% +and postop so it shows what the surgeons +were doing and these are the + + align:start position:0% + + + + align:start position:0% + +preferences much greater preference for + + align:start position:0% +preferences much greater preference for + + + align:start position:0% +preferences much greater preference for +the postoperative C ly for that + + align:start position:0% +the postoperative C ly for that + + + align:start position:0% +the postoperative C ly for that +view so that was one study that because + + align:start position:0% +view so that was one study that because + + + align:start position:0% +view so that was one study that because +they were the very same women involved + + align:start position:0% +they were the very same women involved + + + align:start position:0% +they were the very same women involved +the only thing that was changing in an + + align:start position:0% +the only thing that was changing in an + + + align:start position:0% +the only thing that was changing in an +obvious way was simply that that shape + + align:start position:0% +obvious way was simply that that shape + + + align:start position:0% +obvious way was simply that that shape +that affected their wayist to hip ratio + + align:start position:0% +that affected their wayist to hip ratio + + + align:start position:0% +that affected their wayist to hip ratio +the body mass index um when it did go + + align:start position:0% +the body mass index um when it did go + + + align:start position:0% +the body mass index um when it did go +down didn't seem to make any difference + + align:start position:0% +down didn't seem to make any difference + + + align:start position:0% +down didn't seem to make any difference +in that particular + + align:start position:0% + + + + align:start position:0% + +study so what about reference is shown + + align:start position:0% +study so what about reference is shown + + + align:start position:0% +study so what about reference is shown +by females choosing mates this has been + + align:start position:0% +by females choosing mates this has been + + + align:start position:0% +by females choosing mates this has been +studied also and as we know + + align:start position:0% +studied also and as we know + + + align:start position:0% +studied also and as we know +from uh when we were talking about + + align:start position:0% +from uh when we were talking about + + + align:start position:0% +from uh when we were talking about +Scott's + + align:start position:0% +Scott's + + + align:start position:0% +Scott's +chapters that females tend to make their + + align:start position:0% +chapters that females tend to make their + + + align:start position:0% +chapters that females tend to make their +decisions by different kinds of + + align:start position:0% +decisions by different kinds of + + + align:start position:0% +decisions by different kinds of +means + + align:start position:0% +means + + + align:start position:0% +means +uh it doesn't mean that physical + + align:start position:0% +uh it doesn't mean that physical + + + align:start position:0% +uh it doesn't mean that physical +attractiveness does not make some + + align:start position:0% +attractiveness does not make some + + + align:start position:0% +attractiveness does not make some +difference but it is often not as nearly + + align:start position:0% +difference but it is often not as nearly + + + align:start position:0% +difference but it is often not as nearly +as important for a woman as it is for a + + align:start position:0% +as important for a woman as it is for a + + + align:start position:0% +as important for a woman as it is for a +man and there's reasons evolutionary + + align:start position:0% +man and there's reasons evolutionary + + + align:start position:0% +man and there's reasons evolutionary +reasons for that + + align:start position:0% +reasons for that + + + align:start position:0% +reasons for that +women + + align:start position:0% +women + + + align:start position:0% +women +prefer resource + + align:start position:0% + + + + align:start position:0% + +potential and so You' predict that well + + align:start position:0% +potential and so You' predict that well + + + align:start position:0% +potential and so You' predict that well +they might prer like older men more + + align:start position:0% +they might prer like older men more + + + align:start position:0% +they might prer like older men more +likely to have more + + align:start position:0% +likely to have more + + + align:start position:0% +likely to have more +resources uh they more likely to produce + + align:start position:0% +resources uh they more likely to produce + + + align:start position:0% +resources uh they more likely to produce +preer rich men and so forth uh men with + + align:start position:0% +preer rich men and so forth uh men with + + + align:start position:0% +preer rich men and so forth uh men with +property most men at the age when these + + align:start position:0% +property most men at the age when these + + + align:start position:0% +property most men at the age when these +choices are made don't actually have + + align:start position:0% +choices are made don't actually have + + + align:start position:0% +choices are made don't actually have +property in our society but + + align:start position:0% +property in our society but + + + align:start position:0% +property in our society but +but anyway that's how I would expect + + align:start position:0% +but anyway that's how I would expect + + + align:start position:0% +but anyway that's how I would expect +them to differ and this is if you look + + align:start position:0% +them to differ and this is if you look + + + align:start position:0% +them to differ and this is if you look +at + + align:start position:0% + + + + align:start position:0% + +uh the term maximum reproductive + + align:start position:0% +uh the term maximum reproductive + + + align:start position:0% +uh the term maximum reproductive +potential just has a different a + + align:start position:0% +potential just has a different a + + + align:start position:0% +potential just has a different a +different meaning for women and men and + + align:start position:0% +different meaning for women and men and + + + align:start position:0% +different meaning for women and men and +this is the difference in age + + align:start position:0% +this is the difference in age + + + align:start position:0% +this is the difference in age +preferences uh the mean age this this is + + align:start position:0% +preferences uh the mean age this this is + + + align:start position:0% +preferences uh the mean age this this is +the age + + align:start position:0% +the age + + + align:start position:0% +the age +difference + + align:start position:0% +difference + + + align:start position:0% +difference +uh male greater than + + align:start position:0% +uh male greater than + + + align:start position:0% +uh male greater than +female it's only these to the left of + + align:start position:0% +female it's only these to the left of + + + align:start position:0% +female it's only these to the left of +that vertical line there where + + align:start position:0% +that vertical line there where + + + align:start position:0% +that vertical line there where +the in actual marriages the male uh is + + align:start position:0% +the in actual marriages the male uh is + + + align:start position:0% +the in actual marriages the male uh is +younger than the female these are all + + align:start position:0% +younger than the female these are all + + + align:start position:0% +younger than the female these are all +the ones where the male is older and + + align:start position:0% +the ones where the male is older and + + + align:start position:0% +the ones where the male is older and +note that the peak is roughly 3 + + align:start position:0% +note that the peak is roughly 3 + + + align:start position:0% +note that the peak is roughly 3 +years that's consistent finding in these + + align:start position:0% +years that's consistent finding in these + + + align:start position:0% +years that's consistent finding in these +studies but no notice also a huge range + + align:start position:0% +studies but no notice also a huge range + + + align:start position:0% +studies but no notice also a huge range +okay it goes up of course some women + + align:start position:0% +okay it goes up of course some women + + + align:start position:0% +okay it goes up of course some women +will marry a man that's more than twice + + align:start position:0% +will marry a man that's more than twice + + + align:start position:0% +will marry a man that's more than twice +their age and this does occur so it's + + align:start position:0% +their age and this does occur so it's + + + align:start position:0% +their age and this does occur so it's +all that kind of data is on this this + + align:start position:0% +all that kind of data is on this this + + + align:start position:0% +all that kind of data is on this this +type of curve but you can see it's a + + align:start position:0% +type of curve but you can see it's a + + + align:start position:0% +type of curve but you can see it's a +small small percentage + + align:start position:0% +small small percentage + + + align:start position:0% +small small percentage +there so it's explained by just it's + + align:start position:0% +there so it's explained by just it's + + + align:start position:0% +there so it's explained by just it's +it's predicted by this expectation that + + align:start position:0% +it's predicted by this expectation that + + + align:start position:0% +it's predicted by this expectation that +women are looking more for potential or + + align:start position:0% +women are looking more for potential or + + + align:start position:0% +women are looking more for potential or +actual + + align:start position:0% +actual + + + align:start position:0% +actual +resources all right + + align:start position:0% + + + + align:start position:0% + +humans also have this tendency to stay + + align:start position:0% +humans also have this tendency to stay + + + align:start position:0% +humans also have this tendency to stay +and act within + + align:start position:0% +and act within + + + align:start position:0% +and act within +groups and different groups May compete + + align:start position:0% +groups and different groups May compete + + + align:start position:0% +groups and different groups May compete +with each other sometimes + + align:start position:0% + + + + align:start position:0% + +violently remember the story of Romeo + + align:start position:0% +violently remember the story of Romeo + + + align:start position:0% +violently remember the story of Romeo +and + + align:start position:0% +and + + + align:start position:0% +and +Juliet so uh + + align:start position:0% +Juliet so uh + + + align:start position:0% +Juliet so uh +I I want to try to specify a list of + + align:start position:0% +I I want to try to specify a list of + + + align:start position:0% +I I want to try to specify a list of +evolutionary fit winess benefits of + + align:start position:0% +evolutionary fit winess benefits of + + + align:start position:0% +evolutionary fit winess benefits of +these groupism + + align:start position:0% +these groupism + + + align:start position:0% +these groupism +feelings why do we like to measure to to + + align:start position:0% +feelings why do we like to measure to to + + + align:start position:0% +feelings why do we like to measure to to +choose someone within our group + + align:start position:0% +choose someone within our group + + + align:start position:0% +choose someone within our group +especially if think of earlier Society + + align:start position:0% +especially if think of earlier Society + + + align:start position:0% +especially if think of earlier Society +during our + + align:start position:0% +during our + + + align:start position:0% +during our +Evolution okay and these are the things + + align:start position:0% +Evolution okay and these are the things + + + align:start position:0% +Evolution okay and these are the things +I could come up + + align:start position:0% +I could come up + + + align:start position:0% +I could come up +with higher probability of finding a + + align:start position:0% +with higher probability of finding a + + + align:start position:0% +with higher probability of finding a +mate + + align:start position:0% +mate + + + align:start position:0% +mate +okay higher probability of rescue and + + align:start position:0% +okay higher probability of rescue and + + + align:start position:0% +okay higher probability of rescue and +survival if you lit the stay within that + + align:start position:0% +survival if you lit the stay within that + + + align:start position:0% +survival if you lit the stay within that +group higher probability of better + + align:start position:0% +group higher probability of better + + + align:start position:0% +group higher probability of better +defense against + + align:start position:0% +defense against + + + align:start position:0% +defense against +predators if there's a predator people + + align:start position:0% +predators if there's a predator people + + + align:start position:0% +predators if there's a predator people +in the same + + align:start position:0% +in the same + + + align:start position:0% +in the same +group get together help each other not + + align:start position:0% +group get together help each other not + + + align:start position:0% +group get together help each other not +as likely to help the + + align:start position:0% +as likely to help the + + + align:start position:0% +as likely to help the +outsider higher probability of better + + align:start position:0% +outsider higher probability of better + + + align:start position:0% +outsider higher probability of better +defense against hostile human + + align:start position:0% +defense against hostile human + + + align:start position:0% +defense against hostile human +groups advantages in food acquisition + + align:start position:0% +groups advantages in food acquisition + + + align:start position:0% +groups advantages in food acquisition +Gathering hunting with sharing and + + align:start position:0% +Gathering hunting with sharing and + + + align:start position:0% +Gathering hunting with sharing and +specialization these are all advantages + + align:start position:0% +specialization these are all advantages + + + align:start position:0% +specialization these are all advantages +of being in a group help in child + + align:start position:0% +of being in a group help in child + + + align:start position:0% +of being in a group help in child +rearing and + + align:start position:0% + + + + align:start position:0% + +education and advantages in learning + + align:start position:0% +education and advantages in learning + + + align:start position:0% +education and advantages in learning +from older more experienced group + + align:start position:0% +from older more experienced group + + + align:start position:0% +from older more experienced group +members much more like it's much easier + + align:start position:0% +members much more like it's much easier + + + align:start position:0% +members much more like it's much easier +that's within your group and someone + + align:start position:0% +that's within your group and someone + + + align:start position:0% +that's within your group and someone +from another + + align:start position:0% +from another + + + align:start position:0% +from another +group of course now we formalized + + align:start position:0% +group of course now we formalized + + + align:start position:0% +group of course now we formalized +education so much we cross these + + align:start position:0% +education so much we cross these + + + align:start position:0% +education so much we cross these +boundaries all the time it's not but at + + align:start position:0% +boundaries all the time it's not but at + + + align:start position:0% +boundaries all the time it's not but at +least during our Evolution these are + + align:start position:0% +least during our Evolution these are + + + align:start position:0% +least during our Evolution these are +probably all + + align:start position:0% +probably all + + + align:start position:0% +probably all +uh probably all would be + + align:start position:0% +uh probably all would be + + + align:start position:0% +uh probably all would be +true which would simply explain why + + align:start position:0% +true which would simply explain why + + + align:start position:0% +true which would simply explain why +we've evolved these kinds of + + align:start position:0% + + + + align:start position:0% + +feelings okay then we get to his + + align:start position:0% +feelings okay then we get to his + + + align:start position:0% +feelings okay then we get to his +appendix + + align:start position:0% +appendix + + + align:start position:0% +appendix +questions + + align:start position:0% + + + + align:start position:0% + +uh about the biological basis for + + align:start position:0% +uh about the biological basis for + + + align:start position:0% +uh about the biological basis for +reciprocity among humans the claim is it + + align:start position:0% +reciprocity among humans the claim is it + + + align:start position:0% +reciprocity among humans the claim is it +remains unproven General self and here + + align:start position:0% +remains unproven General self and here + + + align:start position:0% +remains unproven General self and here +the statement is that General + + align:start position:0% +the statement is that General + + + align:start position:0% +the statement is that General +self-interest and an ability to see + + align:start position:0% +self-interest and an ability to see + + + align:start position:0% +self-interest and an ability to see +beyond the short term may be all that's + + align:start position:0% +beyond the short term may be all that's + + + align:start position:0% +beyond the short term may be all that's +required to generate such Behavior so + + align:start position:0% +required to generate such Behavior so + + + align:start position:0% +required to generate such Behavior so +what's the misunderstanding in that kind + + align:start position:0% +what's the misunderstanding in that kind + + + align:start position:0% +what's the misunderstanding in that kind +of statement is very simple they can use + + align:start position:0% +of statement is very simple they can use + + + align:start position:0% +of statement is very simple they can use +approximate and ultimate issues you know + + align:start position:0% +approximate and ultimate issues you know + + + align:start position:0% +approximate and ultimate issues you know +you as we know from before you have to + + align:start position:0% +you as we know from before you have to + + + align:start position:0% +you as we know from before you have to +deal with those things separately + + align:start position:0% +deal with those things separately + + + align:start position:0% +deal with those things separately +understand that there are separate kinds + + align:start position:0% +understand that there are separate kinds + + + align:start position:0% +understand that there are separate kinds +of qu of + + align:start position:0% +of qu of + + + align:start position:0% +of qu of +issues uh + + align:start position:0% +issues uh + + + align:start position:0% +issues uh +what about the idea of languages + + align:start position:0% +what about the idea of languages + + + align:start position:0% +what about the idea of languages +languages vary greatly among human + + align:start position:0% +languages vary greatly among human + + + align:start position:0% +languages vary greatly among human +sociey so if someone claims that this + + align:start position:0% +sociey so if someone claims that this + + + align:start position:0% +sociey so if someone claims that this +fact clearly demonstrates the greater + + align:start position:0% +fact clearly demonstrates the greater + + + align:start position:0% +fact clearly demonstrates the greater +importance of culture than biology in + + align:start position:0% +importance of culture than biology in + + + align:start position:0% +importance of culture than biology in +the control of human behavior how do a + + align:start position:0% +the control of human behavior how do a + + + align:start position:0% +the control of human behavior how do a +sociobiologist deal with that very + + align:start position:0% +sociobiologist deal with that very + + + align:start position:0% +sociobiologist deal with that very +simply the important issue is language + + align:start position:0% +simply the important issue is language + + + align:start position:0% +simply the important issue is language +versus no language not the details of a + + align:start position:0% +versus no language not the details of a + + + align:start position:0% +versus no language not the details of a +particular language that's where chsky + + align:start position:0% +particular language that's where chsky + + + align:start position:0% +particular language that's where chsky +made great contribution pointing out the + + align:start position:0% +made great contribution pointing out the + + + align:start position:0% +made great contribution pointing out the +the form of grammar that's the same one + + align:start position:0% +the form of grammar that's the same one + + + align:start position:0% +the form of grammar that's the same one +language after another after + + align:start position:0% + + + + align:start position:0% + +another so we're born with an innate + + align:start position:0% +another so we're born with an innate + + + align:start position:0% +another so we're born with an innate +ability to learn any language that's + + align:start position:0% +ability to learn any language that's + + + align:start position:0% +ability to learn any language that's +what we + + align:start position:0% + + + + align:start position:0% + +inherit and here's one of Steph j + + align:start position:0% +inherit and here's one of Steph j + + + align:start position:0% +inherit and here's one of Steph j +gr's u statements men are not programmed + + align:start position:0% +gr's u statements men are not programmed + + + align:start position:0% +gr's u statements men are not programmed +by genes to maximize matings nor are + + align:start position:0% +by genes to maximize matings nor are + + + align:start position:0% +by genes to maximize matings nor are +women devoted to monogamy by un + + align:start position:0% +women devoted to monogamy by un + + + align:start position:0% +women devoted to monogamy by un +inalterable nature we can speak only of + + align:start position:0% +inalterable nature we can speak only of + + + align:start position:0% +inalterable nature we can speak only of +capacities not requirements or even + + align:start position:0% +capacities not requirements or even + + + align:start position:0% +capacities not requirements or even +determining propensities therefore our + + align:start position:0% +determining propensities therefore our + + + align:start position:0% +determining propensities therefore our +biology does not make us do + + align:start position:0% +biology does not make us do + + + align:start position:0% +biology does not make us do +it so how do you deal with that kind of + + align:start position:0% +it so how do you deal with that kind of + + + align:start position:0% +it so how do you deal with that kind of +criticism + + align:start position:0% + + + + align:start position:0% + +sociobiology he's pitting culture + + align:start position:0% +sociobiology he's pitting culture + + + align:start position:0% +sociobiology he's pitting culture +against biology culture versus biology + + align:start position:0% +against biology culture versus biology + + + align:start position:0% +against biology culture versus biology +is it's not an either or matter at + + align:start position:0% +is it's not an either or matter at + + + align:start position:0% +is it's not an either or matter at +all as we pointed out both are always + + align:start position:0% + + + + align:start position:0% + +involved okay now this is an + + align:start position:0% +involved okay now this is an + + + align:start position:0% +involved okay now this is an +interesting this is a critique of Alcock + + align:start position:0% +interesting this is a critique of Alcock + + + align:start position:0% +interesting this is a critique of Alcock +in the final paragraph of chapter 7 he + + align:start position:0% +in the final paragraph of chapter 7 he + + + align:start position:0% +in the final paragraph of chapter 7 he +sums up his conclusions about the + + align:start position:0% +sums up his conclusions about the + + + align:start position:0% +sums up his conclusions about the +unlikely philosophy that goul needs and + + align:start position:0% +unlikely philosophy that goul needs and + + + align:start position:0% +unlikely philosophy that goul needs and +many social scientists and some + + align:start position:0% +many social scientists and some + + + align:start position:0% +many social scientists and some +feminists would have a accept largely on + + align:start position:0% +feminists would have a accept largely on + + + align:start position:0% +feminists would have a accept largely on +ideological grounds but then he suddenly + + align:start position:0% +ideological grounds but then he suddenly + + + align:start position:0% +ideological grounds but then he suddenly +shifts the argument and listen to what + + align:start position:0% +shifts the argument and listen to what + + + align:start position:0% +shifts the argument and listen to what +he + + align:start position:0% +he + + + align:start position:0% +he +says that this position has any residual + + align:start position:0% +says that this position has any residual + + + align:start position:0% +says that this position has any residual +credibility can be attributed largely to + + align:start position:0% +credibility can be attributed largely to + + + align:start position:0% +credibility can be attributed largely to +the power of wishful thinking that some + + align:start position:0% +the power of wishful thinking that some + + + align:start position:0% +the power of wishful thinking that some +special meaning occurs to human + + align:start position:0% +special meaning occurs to human + + + align:start position:0% +special meaning occurs to human +existence and this is this is a quote + + align:start position:0% +existence and this is this is a quote + + + align:start position:0% +existence and this is this is a quote +now it is not easy to accept that + + align:start position:0% +now it is not easy to accept that + + + align:start position:0% +now it is not easy to accept that +evolution is a meaningless tale told by + + align:start position:0% +evolution is a meaningless tale told by + + + align:start position:0% +evolution is a meaningless tale told by +an idiot + + align:start position:0% +an idiot + + + align:start position:0% +an idiot +his conclusion is then stated indeed + + align:start position:0% +his conclusion is then stated indeed + + + align:start position:0% +his conclusion is then stated indeed +most people find it hard to believe that + + align:start position:0% +most people find it hard to believe that + + + align:start position:0% +most people find it hard to believe that +blind evolutionary processes have + + align:start position:0% +blind evolutionary processes have + + + align:start position:0% +blind evolutionary processes have +created us a creature whose unconscious + + align:start position:0% +created us a creature whose unconscious + + + align:start position:0% +created us a creature whose unconscious +ultimate goal is no different from that + + align:start position:0% +ultimate goal is no different from that + + + align:start position:0% +ultimate goal is no different from that +of the slime mold the arvar the pine + + align:start position:0% +of the slime mold the arvar the pine + + + align:start position:0% +of the slime mold the arvar the pine +tree and the + + align:start position:0% +tree and the + + + align:start position:0% +tree and the +earthworm although this point is + + align:start position:0% +earthworm although this point is + + + align:start position:0% +earthworm although this point is +evitably U evidently unpalatable it is + + align:start position:0% +evitably U evidently unpalatable it is + + + align:start position:0% +evitably U evidently unpalatable it is +true + + align:start position:0% +true + + + align:start position:0% +true +nevertheless so my criticism of alock + + align:start position:0% +nevertheless so my criticism of alock + + + align:start position:0% +nevertheless so my criticism of alock +here is just that it's very narrow + + align:start position:0% +here is just that it's very narrow + + + align:start position:0% +here is just that it's very narrow +definition of what you mean by an + + align:start position:0% +definition of what you mean by an + + + align:start position:0% +definition of what you mean by an +ultimate + + align:start position:0% + + + + align:start position:0% + +goal there's a the ultimate reason we + + align:start position:0% +goal there's a the ultimate reason we + + + align:start position:0% +goal there's a the ultimate reason we +evolve this way is certainly this very + + align:start position:0% +evolve this way is certainly this very + + + align:start position:0% +evolve this way is certainly this very +simple rule + + align:start position:0% +simple rule + + + align:start position:0% +simple rule +of + + align:start position:0% +of + + + align:start position:0% +of +maximizing genetic + + align:start position:0% +maximizing genetic + + + align:start position:0% +maximizing genetic +fitness so is it really a meaningless + + align:start position:0% +fitness so is it really a meaningless + + + align:start position:0% +fitness so is it really a meaningless +tale told by an idot + + align:start position:0% +tale told by an idot + + + align:start position:0% +tale told by an idot +idiot in my view what is really + + align:start position:0% +idiot in my view what is really + + + align:start position:0% +idiot in my view what is really +incredible and amazing is that the + + align:start position:0% +incredible and amazing is that the + + + align:start position:0% +incredible and amazing is that the +simple and repeated process of genetic + + align:start position:0% +simple and repeated process of genetic + + + align:start position:0% +simple and repeated process of genetic +spread and change following the + + align:start position:0% +spread and change following the + + + align:start position:0% +spread and change following the +biological law of natural selection has + + align:start position:0% +biological law of natural selection has + + + align:start position:0% +biological law of natural selection has +led to such complex creatures with such + + align:start position:0% +led to such complex creatures with such + + + align:start position:0% +led to such complex creatures with such +cognitive capacities with such an + + align:start position:0% +cognitive capacities with such an + + + align:start position:0% +cognitive capacities with such an +ability to ponder the nature of the + + align:start position:0% +ability to ponder the nature of the + + + align:start position:0% +ability to ponder the nature of the +world and its beings and beyond that I + + align:start position:0% +world and its beings and beyond that I + + + align:start position:0% +world and its beings and beyond that I +would add that conscious + + align:start position:0% +would add that conscious + + + align:start position:0% +would add that conscious +beings the sociobiologists the + + align:start position:0% +beings the sociobiologists the + + + align:start position:0% +beings the sociobiologists the +evolutionists have no explanation for + + align:start position:0% +evolutionists have no explanation for + + + align:start position:0% +evolutionists have no explanation for +even existence of + + align:start position:0% +even existence of + + + align:start position:0% +even existence of +Consciousness it's outside their Realm + + align:start position:0% +Consciousness it's outside their Realm + + + align:start position:0% +Consciousness it's outside their Realm +as I pointed out + + align:start position:0% +as I pointed out + + + align:start position:0% +as I pointed out +before okay here's a final topic we have + + align:start position:0% +before okay here's a final topic we have + + + align:start position:0% +before okay here's a final topic we have +four + + align:start position:0% +four + + + align:start position:0% +four +minutes romantic + + align:start position:0% +minutes romantic + + + align:start position:0% +minutes romantic +love is the phenomenon of romantic love + + align:start position:0% +love is the phenomenon of romantic love + + + align:start position:0% +love is the phenomenon of romantic love +the falling in love experience an + + align:start position:0% +the falling in love experience an + + + align:start position:0% +the falling in love experience an +invention of medieval Court life as has + + align:start position:0% +invention of medieval Court life as has + + + align:start position:0% +invention of medieval Court life as has +been repeatedly + + align:start position:0% +been repeatedly + + + align:start position:0% +been repeatedly +asserted in in the in literature and and + + align:start position:0% +asserted in in the in literature and and + + + align:start position:0% +asserted in in the in literature and and +it it's a very popular belief after it + + align:start position:0% +it it's a very popular belief after it + + + align:start position:0% +it it's a very popular belief after it +was first + + align:start position:0% +was first + + + align:start position:0% +was first +propose does it only occur in certain + + align:start position:0% +propose does it only occur in certain + + + align:start position:0% +propose does it only occur in certain +cultures so I want to State a sociu a + + align:start position:0% +cultures so I want to State a sociu a + + + align:start position:0% +cultures so I want to State a sociu a +biological hypothesis concerning its + + align:start position:0% +biological hypothesis concerning its + + + align:start position:0% +biological hypothesis concerning its +Origins because you're working on + + align:start position:0% +Origins because you're working on + + + align:start position:0% +Origins because you're working on +another homework on your topics I'm not + + align:start position:0% +another homework on your topics I'm not + + + align:start position:0% +another homework on your topics I'm not +going to give this as a homework I'm + + align:start position:0% +going to give this as a homework I'm + + + align:start position:0% +going to give this as a homework I'm +going to give you what I would say about + + align:start position:0% +going to give you what I would say about + + + align:start position:0% +going to give you what I would say about +it uh first of + + align:start position:0% + + + + align:start position:0% + +all I would say that the idea was in + + align:start position:0% +all I would say that the idea was in + + + align:start position:0% +all I would say that the idea was in +invented by people who could not accept + + align:start position:0% +invented by people who could not accept + + + align:start position:0% +invented by people who could not accept +the role of innate motivations in humans + + align:start position:0% +the role of innate motivations in humans + + + align:start position:0% +the role of innate motivations in humans +at all and there are many people like + + align:start position:0% +at all and there are many people like + + + align:start position:0% +at all and there are many people like +that okay does it occur only in certain + + align:start position:0% +that okay does it occur only in certain + + + align:start position:0% +that okay does it occur only in certain +cultures it appears to occur in all + + align:start position:0% +cultures it appears to occur in all + + + align:start position:0% +cultures it appears to occur in all +cultures to some degree and there are + + align:start position:0% +cultures to some degree and there are + + + align:start position:0% +cultures to some degree and there are +many cultures that have + + align:start position:0% +many cultures that have + + + align:start position:0% +many cultures that have +um marriages that + + align:start position:0% + + + + align:start position:0% + +are made by the basically deci all the + + align:start position:0% +are made by the basically deci all the + + + align:start position:0% +are made by the basically deci all the +decisions are by the parents and the + + align:start position:0% +decisions are by the parents and the + + + align:start position:0% +decisions are by the parents and the +relatives but even in those + + align:start position:0% +relatives but even in those + + + align:start position:0% +relatives but even in those +cultures they they end up having to + + align:start position:0% +cultures they they end up having to + + + align:start position:0% +cultures they they end up having to +separate well this was an arranged + + align:start position:0% +separate well this was an arranged + + + align:start position:0% +separate well this was an arranged +marriage and that is a love marriage + + align:start position:0% +marriage and that is a love marriage + + + align:start position:0% +marriage and that is a love marriage +they separate them okay and you find + + align:start position:0% +they separate them okay and you find + + + align:start position:0% +they separate them okay and you find +that in all these + + align:start position:0% +that in all these + + + align:start position:0% +that in all these +cultures + + align:start position:0% +cultures + + + align:start position:0% +cultures +uh it's because falling in love still + + align:start position:0% + + + + align:start position:0% + +happens fortunately in societies where + + align:start position:0% +happens fortunately in societies where + + + align:start position:0% +happens fortunately in societies where +the marriages are decided by parents + + align:start position:0% +the marriages are decided by parents + + + align:start position:0% +the marriages are decided by parents +they often work out better when + + align:start position:0% +they often work out better when + + + align:start position:0% +they often work out better when +marriages here where the + + align:start position:0% +marriages here where the + + + align:start position:0% +marriages here where the +rate of divorce is now greater than + + align:start position:0% + + + + align:start position:0% + +50% but let's State a sociobiological + + align:start position:0% +50% but let's State a sociobiological + + + align:start position:0% +50% but let's State a sociobiological +hypothesis about the + + align:start position:0% +hypothesis about the + + + align:start position:0% +hypothesis about the +origins of that feeling it's clearly + + align:start position:0% +origins of that feeling it's clearly + + + align:start position:0% +origins of that feeling it's clearly +instinctive when it if you haven't + + align:start position:0% +instinctive when it if you haven't + + + align:start position:0% +instinctive when it if you haven't +experienced + + align:start position:0% +experienced + + + align:start position:0% +experienced +it uh you will realize when it does + + align:start position:0% +it uh you will realize when it does + + + align:start position:0% +it uh you will realize when it does +occur that you're it's in innate + + align:start position:0% +occur that you're it's in innate + + + align:start position:0% +occur that you're it's in innate +something's happening to you + + align:start position:0% +something's happening to you + + + align:start position:0% +something's happening to you +okay does it occur only in young people + + align:start position:0% +okay does it occur only in young people + + + align:start position:0% +okay does it occur only in young people +no are prominent leaders in the + + align:start position:0% +no are prominent leaders in the + + + align:start position:0% +no are prominent leaders in the +community exempt there's plenty of + + align:start position:0% +community exempt there's plenty of + + + align:start position:0% +community exempt there's plenty of +examples in the news where that's not + + align:start position:0% +examples in the news where that's not + + + align:start position:0% +examples in the news where that's not +true uh if it is evolved as a human + + align:start position:0% +true uh if it is evolved as a human + + + align:start position:0% +true uh if it is evolved as a human +fixed action pattern it's got to be + + align:start position:0% +fixed action pattern it's got to be + + + align:start position:0% +fixed action pattern it's got to be +adaptive in a sociobiological + + align:start position:0% +adaptive in a sociobiological + + + align:start position:0% +adaptive in a sociobiological +sense like many evolved Tendencies it + + align:start position:0% +sense like many evolved Tendencies it + + + align:start position:0% +sense like many evolved Tendencies it +can produce conflicts not only in the + + align:start position:0% +can produce conflicts not only in the + + + align:start position:0% +can produce conflicts not only in the +society but within the individual and + + align:start position:0% +society but within the individual and + + + align:start position:0% +society but within the individual and +this can cause what we call cognitive + + align:start position:0% +this can cause what we call cognitive + + + align:start position:0% +this can cause what we call cognitive +dissonance which the individual will + + align:start position:0% +dissonance which the individual will + + + align:start position:0% +dissonance which the individual will +struggle to resolve in one way or the + + align:start position:0% +struggle to resolve in one way or the + + + align:start position:0% +struggle to resolve in one way or the +other okay so consider why it it must + + align:start position:0% +other okay so consider why it it must + + + align:start position:0% +other okay so consider why it it must +have had to evolve in early human + + align:start position:0% +have had to evolve in early human + + + align:start position:0% +have had to evolve in early human +groups think of the close bonds acquired + + align:start position:0% +groups think of the close bonds acquired + + + align:start position:0% +groups think of the close bonds acquired +in growing up in an extended + + align:start position:0% +in growing up in an extended + + + align:start position:0% +in growing up in an extended +family within which there + + align:start position:0% +family within which there + + + align:start position:0% +family within which there +were very bad consequences of inbreeding + + align:start position:0% +were very bad consequences of inbreeding + + + align:start position:0% +were very bad consequences of inbreeding +it was necessary for genetic fitness to + + align:start position:0% +it was necessary for genetic fitness to + + + align:start position:0% +it was necessary for genetic fitness to +have a motivation that could occur in + + align:start position:0% +have a motivation that could occur in + + + align:start position:0% +have a motivation that could occur in +strength after sexual maturity strong + + align:start position:0% +strength after sexual maturity strong + + + align:start position:0% +strength after sexual maturity strong +enough to cause a young person to leave + + align:start position:0% +enough to cause a young person to leave + + + align:start position:0% +enough to cause a young person to leave +his natal + + align:start position:0% +his natal + + + align:start position:0% +his natal +GOP and the result was what + + align:start position:0% +GOP and the result was what + + + align:start position:0% +GOP and the result was what +we they call often call Roaming In + + align:start position:0% +we they call often call Roaming In + + + align:start position:0% +we they call often call Roaming In +Search of a mate a very common tradition + + align:start position:0% +Search of a mate a very common tradition + + + align:start position:0% +Search of a mate a very common tradition +usually the male but not always just the + + align:start position:0% +usually the male but not always just the + + + align:start position:0% +usually the male but not always just the +male will go off in search of a mate he + + align:start position:0% +male will go off in search of a mate he + + + align:start position:0% +male will go off in search of a mate he +leaves home till he finds a woman he can + + align:start position:0% +leaves home till he finds a woman he can + + + align:start position:0% +leaves home till he finds a woman he can +fall + + align:start position:0% +fall + + + align:start position:0% +fall +for you also have secret Liaisons + + align:start position:0% +for you also have secret Liaisons + + + align:start position:0% +for you also have secret Liaisons +eloping all the other characteristics of + + align:start position:0% +eloping all the other characteristics of + + + align:start position:0% +eloping all the other characteristics of +the falling in love phenomenon including + + align:start position:0% +the falling in love phenomenon including + + + align:start position:0% +the falling in love phenomenon including +behaving stupidly and irrationally + + align:start position:0% +behaving stupidly and irrationally + + + align:start position:0% +behaving stupidly and irrationally +disregarding long-established habits and + + align:start position:0% +disregarding long-established habits and + + + align:start position:0% +disregarding long-established habits and +okay it has a biological reason + + align:start position:0% +okay it has a biological reason + + + align:start position:0% +okay it has a biological reason +okay and then I'll let you just read + + align:start position:0% +okay and then I'll let you just read + + + align:start position:0% +okay and then I'll let you just read +these I put a few summaries of recent + + align:start position:0% +these I put a few summaries of recent + + + align:start position:0% +these I put a few summaries of recent +research and they're very very easy to + + align:start position:0% +research and they're very very easy to + + + align:start position:0% +research and they're very very easy to +find \ No newline at end of file diff --git a/QCGJVKaCDuI.txt b/QCGJVKaCDuI.txt new file mode 100644 index 0000000000000000000000000000000000000000..ae01710cd22074dc78ac14bac14b1391f6a459f0 --- /dev/null +++ b/QCGJVKaCDuI.txt @@ -0,0 +1,419 @@ +align:start position:0% + +hello and welcome back to recitation I'd + + align:start position:0% +hello and welcome back to recitation I'd + + + align:start position:0% +hello and welcome back to recitation I'd +like to uh work on a problem with you + + align:start position:0% +like to uh work on a problem with you + + + align:start position:0% +like to uh work on a problem with you +which is to compute the volume of a + + align:start position:0% +which is to compute the volume of a + + + align:start position:0% +which is to compute the volume of a +parallel pipid using 3x3 determinants so + + align:start position:0% +parallel pipid using 3x3 determinants so + + + align:start position:0% +parallel pipid using 3x3 determinants so +here we've got the parallel pipid drawn + + align:start position:0% +here we've got the parallel pipid drawn + + + align:start position:0% +here we've got the parallel pipid drawn +it has one of its vertices is at the + + align:start position:0% +it has one of its vertices is at the + + + align:start position:0% +it has one of its vertices is at the +origin 0000 0 and the other three edges + + align:start position:0% +origin 0000 0 and the other three edges + + + align:start position:0% +origin 0000 0 and the other three edges +are given to us uh with these + + align:start position:0% +are given to us uh with these + + + align:start position:0% +are given to us uh with these +coordinates here so why don't you take + + align:start position:0% +coordinates here so why don't you take + + + align:start position:0% +coordinates here so why don't you take +some time to work out this problem pause + + align:start position:0% +some time to work out this problem pause + + + align:start position:0% +some time to work out this problem pause +the video and check back with me and + + align:start position:0% +the video and check back with me and + + + align:start position:0% +the video and check back with me and +I'll show you how I solved + + align:start position:0% + + + + align:start position:0% + +it okay welcome back let's get started + + align:start position:0% + + + + align:start position:0% + +so uh the first thing that we uh need to + + align:start position:0% +so uh the first thing that we uh need to + + + align:start position:0% +so uh the first thing that we uh need to +do is we need to remember that Computing + + align:start position:0% +do is we need to remember that Computing + + + align:start position:0% +do is we need to remember that Computing +volumes of parallel pipids is the same + + align:start position:0% +volumes of parallel pipids is the same + + + align:start position:0% +volumes of parallel pipids is the same +thing as Computing 3x3 determinants so + + align:start position:0% +thing as Computing 3x3 determinants so + + + align:start position:0% +thing as Computing 3x3 determinants so +the + + align:start position:0% + + + + align:start position:0% + +volume is just equal to the determinant + + align:start position:0% +volume is just equal to the determinant + + + align:start position:0% +volume is just equal to the determinant +uh which is built out of the vectors uh + + align:start position:0% +uh which is built out of the vectors uh + + + align:start position:0% +uh which is built out of the vectors uh +the row vectors determining the edges so + + align:start position:0% +the row vectors determining the edges so + + + align:start position:0% +the row vectors determining the edges so +we + + align:start position:0% + + + + align:start position:0% + +have well that's almost true um this + + align:start position:0% +have well that's almost true um this + + + align:start position:0% +have well that's almost true um this +determinant will be uh either a positive + + align:start position:0% +determinant will be uh either a positive + + + align:start position:0% +determinant will be uh either a positive +or A negative number and we always want + + align:start position:0% +or A negative number and we always want + + + align:start position:0% +or A negative number and we always want +to take the positive number so I'm going + + align:start position:0% +to take the positive number so I'm going + + + align:start position:0% +to take the positive number so I'm going +to write plus or minus here and we'll + + align:start position:0% +to write plus or minus here and we'll + + + align:start position:0% +to write plus or minus here and we'll +have to remember at the end that we want + + align:start position:0% +have to remember at the end that we want + + + align:start position:0% +have to remember at the end that we want +a positive number so we can compute this + + align:start position:0% +a positive number so we can compute this + + + align:start position:0% +a positive number so we can compute this +determinant using lass expansion as we + + align:start position:0% +determinant using lass expansion as we + + + align:start position:0% +determinant using lass expansion as we +did in the last + + align:start position:0% +did in the last + + + align:start position:0% +did in the last +video so for lla expansion we take the + + align:start position:0% +video so for lla expansion we take the + + + align:start position:0% +video so for lla expansion we take the +we can do lass expansion on the first + + align:start position:0% +we can do lass expansion on the first + + + align:start position:0% +we can do lass expansion on the first +row and that will again be nice because + + align:start position:0% +row and that will again be nice because + + + align:start position:0% +row and that will again be nice because +uh this zero here will make our + + align:start position:0% +uh this zero here will make our + + + align:start position:0% +uh this zero here will make our +computation simpler and so remember + + align:start position:0% +computation simpler and so remember + + + align:start position:0% +computation simpler and so remember +remember what we do is we take the first + + align:start position:0% +remember what we do is we take the first + + + align:start position:0% +remember what we do is we take the first +entry in the row and then we need to + + align:start position:0% +entry in the row and then we need to + + + align:start position:0% +entry in the row and then we need to +multiply by the minor that we get by + + align:start position:0% +multiply by the minor that we get by + + + align:start position:0% +multiply by the minor that we get by +covering up that row and that column so + + align:start position:0% +covering up that row and that column so + + + align:start position:0% +covering up that row and that column so +we have this this little 2x two + + align:start position:0% +we have this this little 2x two + + + align:start position:0% +we have this this little 2x two +determinant which looks like minus + + align:start position:0% + + + + align:start position:0% + +one and now we need to + + align:start position:0% +one and now we need to + + + align:start position:0% +one and now we need to +subtract uh the next entry in the row + + align:start position:0% +subtract uh the next entry in the row + + + align:start position:0% +subtract uh the next entry in the row +times uh its minor which is now this + + align:start position:0% +times uh its minor which is now this + + + align:start position:0% +times uh its minor which is now this +Matrix 1 1 0 + + align:start position:0% + + + + align:start position:0% + +1 so take that determinant we get 1 uh + + align:start position:0% +1 so take that determinant we get 1 uh + + + align:start position:0% +1 so take that determinant we get 1 uh +minus 0 so Al together we get one so + + align:start position:0% +minus 0 so Al together we get one so + + + align:start position:0% +minus 0 so Al together we get one so +what that tells us is that our uh our uh + + align:start position:0% +what that tells us is that our uh our uh + + + align:start position:0% +what that tells us is that our uh our uh +determinant is uh Min + + align:start position:0% + + + + align:start position:0% + +-4 but then that tells us that our + + align:start position:0% + + + + align:start position:0% + +volume + + align:start position:0% +volume + + + align:start position:0% +volume +is+ 4 and I'll leave it at that \ No newline at end of file diff --git a/QCo-RtfLzyc.txt b/QCo-RtfLzyc.txt new file mode 100644 index 0000000000000000000000000000000000000000..f0eb0f202b035543105f24603bde3466d8a5eabc --- /dev/null +++ b/QCo-RtfLzyc.txt @@ -0,0 +1,241 @@ +For some applications, data naturally comes +in vector or matrix form. + +For example, a vector of digitized samples +representing an audio waveform over time, + +or a matrix of pixel colors in a 2D image +from a camera. + +When processing that data, it's common to +perform the same sequence of operations on + +each data element. + +The example code shown here is computing a +vector sum, where each component of one vector + +is added to the corresponding component of +another vector. + +By replicating the datapath portion of our +CPU, we can design special-purpose vector + +processors capable of performing the same +operation on many data elements in parallel. + +Here we see that the register file and ALU +have been replicated and the control signals + +from decoding the current instruction are +shared by all the datapaths. + +Data is fetched from memory in big blocks +(very much like fetching a cache line) and + +the specified register in each datapath is +loaded with one of the words from the block. + +Similarly each datapath can contribute a word +to be stored as a contiguous block in main + +memory. + +In such machines, the width of the data buses +to and from main memory is many words wide, + +so a single memory access provides data for +all the datapaths in parallel. + +Executing a single instruction on a machine +with N datapaths is equivalent to executing + +N instructions on a conventional machine with +a single datapath. + +The result achieves a lot of parallelism without +the complexities of out-of-order superscalar + +execution. + +Suppose we had a vector processor with 16 +datapaths. + +Let's compare its performance on a vector-sum +operation to that of a conventional pipelined + +Beta processor. + +Here's the Beta code, carefully organized +to avoid any data hazards during execution. + +There are 9 instructions in the loop, taking +10 cycles to execute if we count the NOP introduced + +into the pipeline when the BNE at the end +of the loop is taken. + +It takes 160 cycles to sum all 16 elements +assuming no additional cycles are required + +due to cache misses. + +And here's the corresponding code for a vector +processor where we've assumed constant-sized + +16-element vectors. + +Note that "V" registers refer to a particular +location in the register file associated with + +each datapath, while the "R" registers are +the conventional Beta registers used for address + +computations, etc. + +It would only take 4 cycles for the vector +processor to complete the desired operations, + +a speed-up of 40. + +This example shows the best-possible speed-up. + +The key to a good speed-up is our ability +to "vectorize" the code and take advantage + +of all the datapaths operating in parallel. + +This isn't possible for every application, +but for tasks like audio or video encoding + +and decoding, and all sorts of digital signal +processing, vectorization is very doable. + +Memory operations enjoy a similar performance +improvement since the access overhead is amortized + +over large blocks of data. + +You might wonder if it's possible to efficiently +perform data-dependent operations on a vector + +processor. + +Data-dependent operations appear as conditional +statements on conventional machines, where + +the body of the statement is executed if the +condition is true. + +If testing and branching is under the control +of the single-instruction execution engine, + +how can we take advantage of the parallel +datapaths? + +The trick is provide each datapath with a +local predicate flag. + +Use a vectorized compare instruction (CMPLT.V) +to perform the a[i] < b[i] comparisons in + +parallel and remember the result locally in +each datapath's predicate flag. + +Then extend the vector ISA to include "predicated +instructions" which check the local predicate + +to see if they should execute or do nothing. + +In this example, ADDC.V.iftrue only performs +the ADDC on the local data if the local predicate + +flag is true. + +Instruction predication is also used in many +non-vector architectures to avoid the execution-time + +penalties associated with mis-predicted conditional +branches. + +They are particularly useful for simple arithmetic +and boolean operations (i.e., very short instruction + +sequences) that should be executed only if +a condition is met. + +The x86 ISA includes a conditional move instruction, +and in the 32-bit ARM ISA almost all instructions + +can be conditionally executed. + +The power of vector processors comes from +having 1 instruction initiate N parallel operations + +on N pairs of operands. + +Most modern CPUs incorporate vector extensions +that operate in parallel on 8-, 16-, 32- or + +64-bit operands organized as blocks of 128-, +256-, or 512-bit data. + +Often all that's needed is some simple additional +logic on an ALU designed to process full-width + +operands. + +The parallelism is baked into the vector program, +not discovered on-the-fly by the instruction + +dispatch and execution machinery. + +Writing the specialized vector programs is +a worthwhile investment for certain library + +functions which see a lot use in processing +today's information streams with their heavy + +use of images, and A/V material. + +Perhaps the best example of architectures +with many datapaths operating in parallel + +are the graphics processing units (GPUs) found +in almost all computer graphics systems. + +GPU datapaths are typically specialized for +32- and 64-bit floating point operations found + +in the algorithms needed to display in real-time +a 3D scene represented as billions of triangular + +patches as a 2D image on the computer screen. + +Coordinate transformation, pixel shading and +antialiasing, texture mapping, etc., are examples + +of "embarrassingly parallel" computations +where the parallelism comes from having to + +perform the same computation independently +on millions of different data objects. + +Similar problems can be found in the fields +of bioinformatics, big data processing, neural + +net emulation used in deep machine learning, +and so on. + +Increasingly, GPUs are used in many interesting +scientific and engineering calculations and + +not just as graphics engines. + +Data-level parallelism provides significant +performance improvements in a variety of useful + +situations. + +So current and future ISAs will almost certainly +include support for vector operations. \ No newline at end of file diff --git a/RDvMzWDzZkc.txt b/RDvMzWDzZkc.txt new file mode 100644 index 0000000000000000000000000000000000000000..b936c143ef6c3e28cb6f524bdb1dfe79e99cb007 --- /dev/null +++ b/RDvMzWDzZkc.txt @@ -0,0 +1,13131 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT OpenCourseWare continue to + + align:start position:0% +will help MIT OpenCourseWare continue to + + + align:start position:0% +will help MIT OpenCourseWare continue to +offer high quality educational resources + + align:start position:0% +offer high quality educational resources + + + align:start position:0% +offer high quality educational resources +for free + + align:start position:0% +for free + + + align:start position:0% +for free +to make a donation or to view additional + + align:start position:0% +to make a donation or to view additional + + + align:start position:0% +to make a donation or to view additional +materials from hundreds of MIT courses + + align:start position:0% +materials from hundreds of MIT courses + + + align:start position:0% +materials from hundreds of MIT courses +visit MIT opencourseware at ocw.mit.edu + + align:start position:0% + + + + align:start position:0% + +let me just introduce myself and then + + align:start position:0% +let me just introduce myself and then + + + align:start position:0% +let me just introduce myself and then +maybe you all can introduce yourself + + align:start position:0% +maybe you all can introduce yourself + + + align:start position:0% +maybe you all can introduce yourself +yourselves to me and to each other so + + align:start position:0% +yourselves to me and to each other so + + + align:start position:0% +yourselves to me and to each other so +I'm bill bond villian and for the last + + align:start position:0% +I'm bill bond villian and for the last + + + align:start position:0% +I'm bill bond villian and for the last +11 years I have been director of mi + + align:start position:0% +11 years I have been director of mi + + + align:start position:0% +11 years I have been director of mi +t--'s Washington DC office and I've + + align:start position:0% +t--'s Washington DC office and I've + + + align:start position:0% +t--'s Washington DC office and I've +taught at Georgetown University of + + align:start position:0% +taught at Georgetown University of + + + align:start position:0% +taught at Georgetown University of +course on science and tech policy for + + align:start position:0% +course on science and tech policy for + + + align:start position:0% +course on science and tech policy for +about 12 years and I teach different + + align:start position:0% +about 12 years and I teach different + + + align:start position:0% +about 12 years and I teach different +course on energy technology policy at + + align:start position:0% +course on energy technology policy at + + + align:start position:0% +course on energy technology policy at +Johns Hopkins sighs so I'm on the edge + + align:start position:0% +Johns Hopkins sighs so I'm on the edge + + + align:start position:0% +Johns Hopkins sighs so I'm on the edge +I'm faculty at Georgetown and Hopkins + + align:start position:0% +I'm faculty at Georgetown and Hopkins + + + align:start position:0% +I'm faculty at Georgetown and Hopkins +ice and after 11 years of being director + + align:start position:0% +ice and after 11 years of being director + + + align:start position:0% +ice and after 11 years of being director +the Washington office I've stepped down + + align:start position:0% +the Washington office I've stepped down + + + align:start position:0% +the Washington office I've stepped down +from that job so I'm now a lecturer up + + align:start position:0% +from that job so I'm now a lecturer up + + + align:start position:0% +from that job so I'm now a lecturer up +here and I've got a an attachment to mi + + align:start position:0% +here and I've got a an attachment to mi + + + align:start position:0% +here and I've got a an attachment to mi +t--'s Industrial Policy Center which is + + align:start position:0% +t--'s Industrial Policy Center which is + + + align:start position:0% +t--'s Industrial Policy Center which is +one of its policy centers and I'm + + align:start position:0% +one of its policy centers and I'm + + + align:start position:0% +one of its policy centers and I'm +finishing my third book actually just + + align:start position:0% +finishing my third book actually just + + + align:start position:0% +finishing my third book actually just +now at MIT press on advanced + + align:start position:0% +now at MIT press on advanced + + + align:start position:0% +now at MIT press on advanced +manufacturing so you're gonna hear more + + align:start position:0% +manufacturing so you're gonna hear more + + + align:start position:0% +manufacturing so you're gonna hear more +than your share about manufacturing for + + align:start position:0% +than your share about manufacturing for + + + align:start position:0% +than your share about manufacturing for +this all over you're stuck with those + + align:start position:0% +this all over you're stuck with those + + + align:start position:0% +this all over you're stuck with those +realities and you know I had a kind of a + + align:start position:0% +realities and you know I had a kind of a + + + align:start position:0% +realities and you know I had a kind of a +background in I was in the executive + + align:start position:0% +background in I was in the executive + + + align:start position:0% +background in I was in the executive +branch as a child and I was a Deputy + + align:start position:0% +branch as a child and I was a Deputy + + + align:start position:0% +branch as a child and I was a Deputy +Assistant Secretary of Transportation of + + align:start position:0% +Assistant Secretary of Transportation of + + + align:start position:0% +Assistant Secretary of Transportation of +my youth long before any of you were + + align:start position:0% +my youth long before any of you were + + + align:start position:0% +my youth long before any of you were +born and got to really engage in the + + align:start position:0% +born and got to really engage in the + + + align:start position:0% +born and got to really engage in the +development of major legislation that + + align:start position:0% +development of major legislation that + + + align:start position:0% +development of major legislation that +deregulated most of the big + + align:start position:0% +deregulated most of the big + + + align:start position:0% +deregulated most of the big +transportation sectors so aviation + + align:start position:0% +transportation sectors so aviation + + + align:start position:0% +transportation sectors so aviation +trucking and railroads and then did a + + align:start position:0% +trucking and railroads and then did a + + + align:start position:0% +trucking and railroads and then did a +lot of work on Surface Transportation + + align:start position:0% +lot of work on Surface Transportation + + + align:start position:0% +lot of work on Surface Transportation +then practice law because I've been + + align:start position:0% +then practice law because I've been + + + align:start position:0% +then practice law because I've been +trained as a lawyer so practice law for + + align:start position:0% +trained as a lawyer so practice law for + + + align:start position:0% +trained as a lawyer so practice law for +a decade and then somebody I knew and + + align:start position:0% +a decade and then somebody I knew and + + + align:start position:0% +a decade and then somebody I knew and +had worked with at an earlier stage + + align:start position:0% +had worked with at an earlier stage + + + align:start position:0% +had worked with at an earlier stage +became US senators so I got one of those + + align:start position:0% +became US senators so I got one of those + + + align:start position:0% +became US senators so I got one of those +proverbial Washington phone calls you + + align:start position:0% +proverbial Washington phone calls you + + + align:start position:0% +proverbial Washington phone calls you +know why don't you come up and we'll + + align:start position:0% +know why don't you come up and we'll + + + align:start position:0% +know why don't you come up and we'll +talk bill and that conversation lasted + + align:start position:0% +talk bill and that conversation lasted + + + align:start position:0% +talk bill and that conversation lasted +for over 15 years so I couldn't resist + + align:start position:0% +for over 15 years so I couldn't resist + + + align:start position:0% +for over 15 years so I couldn't resist +staying up there it was much too + + align:start position:0% +staying up there it was much too + + + align:start position:0% +staying up there it was much too +interesting and fun so had a long + + align:start position:0% +interesting and fun so had a long + + + align:start position:0% +interesting and fun so had a long +we're working in the US Senate and + + align:start position:0% +we're working in the US Senate and + + + align:start position:0% +we're working in the US Senate and +worked on lots of legislation but + + align:start position:0% +worked on lots of legislation but + + + align:start position:0% +worked on lots of legislation but +including a lot of work on innovation + + align:start position:0% +including a lot of work on innovation + + + align:start position:0% +including a lot of work on innovation +policy and science policy and R&D policy + + align:start position:0% +policy and science policy and R&D policy + + + align:start position:0% +policy and science policy and R&D policy +so that's kind of where I got my + + align:start position:0% +so that's kind of where I got my + + + align:start position:0% +so that's kind of where I got my +training in this territory it was very + + align:start position:0% +training in this territory it was very + + + align:start position:0% +training in this territory it was very +much learning by doing and then 11 years + + align:start position:0% +much learning by doing and then 11 years + + + align:start position:0% +much learning by doing and then 11 years +ago I went to MIT to run their + + align:start position:0% +ago I went to MIT to run their + + + align:start position:0% +ago I went to MIT to run their +Washington office which has been a great + + align:start position:0% +Washington office which has been a great + + + align:start position:0% +Washington office which has been a great +joy so anyway that's kind of and then I + + align:start position:0% +joy so anyway that's kind of and then I + + + align:start position:0% +joy so anyway that's kind of and then I +just as I said just stepped down so from + + align:start position:0% +just as I said just stepped down so from + + + align:start position:0% +just as I said just stepped down so from +that very activist kind of job to this + + align:start position:0% +that very activist kind of job to this + + + align:start position:0% +that very activist kind of job to this +life of leisurely MIT faculty you know + + align:start position:0% +life of leisurely MIT faculty you know + + + align:start position:0% +life of leisurely MIT faculty you know +supposedly I'm quasi retired I doubt it + + align:start position:0% +supposedly I'm quasi retired I doubt it + + + align:start position:0% +supposedly I'm quasi retired I doubt it +but in anyway that's my background let + + align:start position:0% +but in anyway that's my background let + + + align:start position:0% +but in anyway that's my background let +me let me just say a few things about + + align:start position:0% +me let me just say a few things about + + + align:start position:0% +me let me just say a few things about +how this course is going to work you + + align:start position:0% +how this course is going to work you + + + align:start position:0% +how this course is going to work you +know we know from a lot of studies and + + align:start position:0% +know we know from a lot of studies and + + + align:start position:0% +know we know from a lot of studies and +MIT s online crowd is now doing about + + align:start position:0% +MIT s online crowd is now doing about + + + align:start position:0% +MIT s online crowd is now doing about +learning science that the talking head + + align:start position:0% +learning science that the talking head + + + align:start position:0% +learning science that the talking head +is not an efficient way to learn so we + + align:start position:0% +is not an efficient way to learn so we + + + align:start position:0% +is not an efficient way to learn so we +really need you all participating in a + + align:start position:0% +really need you all participating in a + + + align:start position:0% +really need you all participating in a +class and coming into the discussions so + + align:start position:0% +class and coming into the discussions so + + + align:start position:0% +class and coming into the discussions so +to further that and you saw my email + + align:start position:0% +to further that and you saw my email + + + align:start position:0% +to further that and you saw my email +kind of introducing the course and + + align:start position:0% +kind of introducing the course and + + + align:start position:0% +kind of introducing the course and +you've seen the discussion the syllabus + + align:start position:0% +you've seen the discussion the syllabus + + + align:start position:0% +you've seen the discussion the syllabus +those of you who haven't been able to + + align:start position:0% +those of you who haven't been able to + + + align:start position:0% +those of you who haven't been able to +get online yet let's stick around for + + align:start position:0% +get online yet let's stick around for + + + align:start position:0% +get online yet let's stick around for +after class let's make sure you get + + align:start position:0% +after class let's make sure you get + + + align:start position:0% +after class let's make sure you get +registered and get access to the online + + align:start position:0% +registered and get access to the online + + + align:start position:0% +registered and get access to the online +materials in the background materials so + + align:start position:0% +materials in the background materials so + + + align:start position:0% +materials in the background materials so +let's talk for a few minutes after class + + align:start position:0% +let's talk for a few minutes after class + + + align:start position:0% +let's talk for a few minutes after class +but essentially we're going to use a + + align:start position:0% +but essentially we're going to use a + + + align:start position:0% +but essentially we're going to use a +discussion leader system and what that + + align:start position:0% +discussion leader system and what that + + + align:start position:0% +discussion leader system and what that +means is that we'll all have you know + + align:start position:0% +means is that we'll all have you know + + + align:start position:0% +means is that we'll all have you know +five readings or so for each class and + + align:start position:0% +five readings or so for each class and + + + align:start position:0% +five readings or so for each class and +I'm gonna ask all of you to do those + + align:start position:0% +I'm gonna ask all of you to do those + + + align:start position:0% +I'm gonna ask all of you to do those +readings and then do a short doesn't + + align:start position:0% +readings and then do a short doesn't + + + align:start position:0% +readings and then do a short doesn't +need me more than a page it shouldn't + + align:start position:0% +need me more than a page it shouldn't + + + align:start position:0% +need me more than a page it shouldn't +really be more than a page and a half + + align:start position:0% +really be more than a page and a half + + + align:start position:0% +really be more than a page and a half +some key bullet points on the key + + align:start position:0% +some key bullet points on the key + + + align:start position:0% +some key bullet points on the key +findings that you drew from those + + align:start position:0% +findings that you drew from those + + + align:start position:0% +findings that you drew from those +readings and a couple of questions right + + align:start position:0% +readings and a couple of questions right + + + align:start position:0% +readings and a couple of questions right +so that kind of gets all of you thinking + + align:start position:0% +so that kind of gets all of you thinking + + + align:start position:0% +so that kind of gets all of you thinking +about the readings on the way in and + + align:start position:0% +about the readings on the way in and + + + align:start position:0% +about the readings on the way in and +some cute questions you've got about the + + align:start position:0% +some cute questions you've got about the + + + align:start position:0% +some cute questions you've got about the +so that you can help own the class right + + align:start position:0% +so that you can help own the class right + + + align:start position:0% +so that you can help own the class right +because it only works if you all own it + + align:start position:0% +because it only works if you all own it + + + align:start position:0% +because it only works if you all own it +and then in turn will do this discussion + + align:start position:0% +and then in turn will do this discussion + + + align:start position:0% +and then in turn will do this discussion +leader thing so each week I'll ask a + + align:start position:0% +leader thing so each week I'll ask a + + + align:start position:0% +leader thing so each week I'll ask a +couple of you to be leaders of the Q&A + + align:start position:0% +couple of you to be leaders of the Q&A + + + align:start position:0% +couple of you to be leaders of the Q&A +part of the class so here's here's how + + align:start position:0% +part of the class so here's here's how + + + align:start position:0% +part of the class so here's here's how +it will work so I'll talk about any + + align:start position:0% +it will work so I'll talk about any + + + align:start position:0% +it will work so I'll talk about any +given reading for maybe 10 minutes maybe + + align:start position:0% +given reading for maybe 10 minutes maybe + + + align:start position:0% +given reading for maybe 10 minutes maybe +a little more than that right and then + + align:start position:0% +a little more than that right and then + + + align:start position:0% +a little more than that right and then +I'm going to turn it over to the + + align:start position:0% +I'm going to turn it over to the + + + align:start position:0% +I'm going to turn it over to the +discussion leader to kind of bring you + + align:start position:0% +discussion leader to kind of bring you + + + align:start position:0% +discussion leader to kind of bring you +all into the review of the reading right + + align:start position:0% +all into the review of the reading right + + + align:start position:0% +all into the review of the reading right +so that you get to participate in this + + align:start position:0% +so that you get to participate in this + + + align:start position:0% +so that you get to participate in this +and get you get your thoughts out on the + + align:start position:0% +and get you get your thoughts out on the + + + align:start position:0% +and get you get your thoughts out on the +table and importantly in terms of your + + align:start position:0% +table and importantly in terms of your + + + align:start position:0% +table and importantly in terms of your +learning process you're thinking you're + + align:start position:0% +learning process you're thinking you're + + + align:start position:0% +learning process you're thinking you're +learning you're speaking all of those + + align:start position:0% +learning you're speaking all of those + + + align:start position:0% +learning you're speaking all of those +are key to the learning process one + + align:start position:0% +are key to the learning process one + + + align:start position:0% +are key to the learning process one +thing which we know from MIT is online + + align:start position:0% +thing which we know from MIT is online + + + align:start position:0% +thing which we know from MIT is online +classes and the learning science that's + + align:start position:0% +classes and the learning science that's + + + align:start position:0% +classes and the learning science that's +work that's been going with them is that + + align:start position:0% +work that's been going with them is that + + + align:start position:0% +work that's been going with them is that +the human memory fades after more than + + align:start position:0% +the human memory fades after more than + + + align:start position:0% +the human memory fades after more than +ten minutes of the talking head I mean + + align:start position:0% +ten minutes of the talking head I mean + + + align:start position:0% +ten minutes of the talking head I mean +it is just not rememberable right and + + align:start position:0% +it is just not rememberable right and + + + align:start position:0% +it is just not rememberable right and +it's very important to change settings + + align:start position:0% +it's very important to change settings + + + align:start position:0% +it's very important to change settings +after that so we're gonna change + + align:start position:0% +after that so we're gonna change + + + align:start position:0% +after that so we're gonna change +settings and it's going to be you and + + align:start position:0% +settings and it's going to be you and + + + align:start position:0% +settings and it's going to be you and +you all are gonna kind of lead the next + + align:start position:0% +you all are gonna kind of lead the next + + + align:start position:0% +you all are gonna kind of lead the next +phase and then we'll go to the next + + align:start position:0% +phase and then we'll go to the next + + + align:start position:0% +phase and then we'll go to the next +reading after we talked about the + + align:start position:0% +reading after we talked about the + + + align:start position:0% +reading after we talked about the +initial one for awhile we'll go to the + + align:start position:0% +initial one for awhile we'll go to the + + + align:start position:0% +initial one for awhile we'll go to the +next reading and follow this pattern + + align:start position:0% +next reading and follow this pattern + + + align:start position:0% +next reading and follow this pattern +through and then I will always try to + + align:start position:0% +through and then I will always try to + + + align:start position:0% +through and then I will always try to +summarize either at the beginning of the + + align:start position:0% +summarize either at the beginning of the + + + align:start position:0% +summarize either at the beginning of the +end of the class where we are because we + + align:start position:0% +end of the class where we are because we + + + align:start position:0% +end of the class where we are because we +also know that repetition is key to + + align:start position:0% +also know that repetition is key to + + + align:start position:0% +also know that repetition is key to +learning too so just a few elementary + + align:start position:0% +learning too so just a few elementary + + + align:start position:0% +learning too so just a few elementary +points about learning science there + + align:start position:0% +points about learning science there + + + align:start position:0% +points about learning science there +really is actually some design here the + + align:start position:0% +really is actually some design here the + + + align:start position:0% +really is actually some design here the +discussion leader stuff is going to be + + align:start position:0% +discussion leader stuff is going to be + + + align:start position:0% +discussion leader stuff is going to be +very informal this is going to be very + + align:start position:0% +very informal this is going to be very + + + align:start position:0% +very informal this is going to be very +relaxed I don't want you to be concerned + + align:start position:0% +relaxed I don't want you to be concerned + + + align:start position:0% +relaxed I don't want you to be concerned +about have to do fancy presentations + + align:start position:0% +about have to do fancy presentations + + + align:start position:0% +about have to do fancy presentations +just you know speak for a few minutes + + align:start position:0% +just you know speak for a few minutes + + + align:start position:0% +just you know speak for a few minutes +about some key things that you found + + align:start position:0% +about some key things that you found + + + align:start position:0% +about some key things that you found +about the particular reading and then + + align:start position:0% +about the particular reading and then + + + align:start position:0% +about the particular reading and then +try and draw out your classmates now + + align:start position:0% +try and draw out your classmates now + + + align:start position:0% +try and draw out your classmates now +you'll get there one-pagers their + + align:start position:0% +you'll get there one-pagers their + + + align:start position:0% +you'll get there one-pagers their +reading summaries in advance they'll get + + align:start position:0% +reading summaries in advance they'll get + + + align:start position:0% +reading summaries in advance they'll get +you cut through those the day in advance + + align:start position:0% +you cut through those the day in advance + + + align:start position:0% +you cut through those the day in advance +I'll get a copy to write so I'm going to + + align:start position:0% +I'll get a copy to write so I'm going to + + + align:start position:0% +I'll get a copy to write so I'm going to +set up a rough discussion leader agenda + + align:start position:0% +set up a rough discussion leader agenda + + + align:start position:0% +set up a rough discussion leader agenda +for the first few classes and then we'll + + align:start position:0% +for the first few classes and then we'll + + + align:start position:0% +for the first few classes and then we'll +formalize it for the whole class but + + align:start position:0% +formalize it for the whole class but + + + align:start position:0% +formalize it for the whole class but +all of you will be discussion leaders + + align:start position:0% +all of you will be discussion leaders + + + align:start position:0% +all of you will be discussion leaders +probably at least a couple of times but + + align:start position:0% +probably at least a couple of times but + + + align:start position:0% +probably at least a couple of times but +again it's very relaxed it's very + + align:start position:0% +again it's very relaxed it's very + + + align:start position:0% +again it's very relaxed it's very +informal and you know we're just gonna + + align:start position:0% +informal and you know we're just gonna + + + align:start position:0% +informal and you know we're just gonna +be sitting around the table and I want + + align:start position:0% +be sitting around the table and I want + + + align:start position:0% +be sitting around the table and I want +you to kind of really work to bring your + + align:start position:0% +you to kind of really work to bring your + + + align:start position:0% +you to kind of really work to bring your +classmates you know into the into the + + align:start position:0% +classmates you know into the into the + + + align:start position:0% +classmates you know into the into the +talking so questions about this let me + + align:start position:0% +talking so questions about this let me + + + align:start position:0% +talking so questions about this let me +talk about where this class is going to + + align:start position:0% +talk about where this class is going to + + + align:start position:0% +talk about where this class is going to +go so you get a sense of the pieces that + + align:start position:0% +go so you get a sense of the pieces that + + + align:start position:0% +go so you get a sense of the pieces that +lie ahead so the first couple of classes + + align:start position:0% +lie ahead so the first couple of classes + + + align:start position:0% +lie ahead so the first couple of classes +are really introductory and you know + + align:start position:0% +are really introductory and you know + + + align:start position:0% +are really introductory and you know +today's class as those of you were able + + align:start position:0% +today's class as those of you were able + + + align:start position:0% +today's class as those of you were able +to get to the site saw is really about + + align:start position:0% +to get to the site saw is really about + + + align:start position:0% +to get to the site saw is really about +economic growth theory + + align:start position:0% +economic growth theory + + + align:start position:0% +economic growth theory +all right so innovation growth theory + + align:start position:0% +all right so innovation growth theory + + + align:start position:0% +all right so innovation growth theory +and that's foundational in other words + + align:start position:0% +and that's foundational in other words + + + align:start position:0% +and that's foundational in other words +why do we what are the pillars on which + + align:start position:0% +why do we what are the pillars on which + + + align:start position:0% +why do we what are the pillars on which +studying innovation rests clearly the + + align:start position:0% +studying innovation rests clearly the + + + align:start position:0% +studying innovation rests clearly the +economic justification is one of the + + align:start position:0% +economic justification is one of the + + + align:start position:0% +economic justification is one of the +absolute central and probably the + + align:start position:0% +absolute central and probably the + + + align:start position:0% +absolute central and probably the +critical one so what does innovation + + align:start position:0% +critical one so what does innovation + + + align:start position:0% +critical one so what does innovation +growth policy how does it think how is + + align:start position:0% +growth policy how does it think how is + + + align:start position:0% +growth policy how does it think how is +it organized and we're going to be + + align:start position:0% +it organized and we're going to be + + + align:start position:0% +it organized and we're going to be +reading two very famous growth + + align:start position:0% +reading two very famous growth + + + align:start position:0% +reading two very famous growth +economists and talking about them three + + align:start position:0% +economists and talking about them three + + + align:start position:0% +economists and talking about them three +actually and kind of trying to put + + align:start position:0% +actually and kind of trying to put + + + align:start position:0% +actually and kind of trying to put +together what the basics of growth + + align:start position:0% +together what the basics of growth + + + align:start position:0% +together what the basics of growth +theory so that we understand that it can + + align:start position:0% +theory so that we understand that it can + + + align:start position:0% +theory so that we understand that it can +use that then the second class moves + + align:start position:0% +use that then the second class moves + + + align:start position:0% +use that then the second class moves +into kind of a second part of growth + + align:start position:0% +into kind of a second part of growth + + + align:start position:0% +into kind of a second part of growth +theory and we could call this innovation + + align:start position:0% +theory and we could call this innovation + + + align:start position:0% +theory and we could call this innovation +systems in other words innovation occurs + + align:start position:0% + + + + align:start position:0% + +in a system and you have to understand + + align:start position:0% +in a system and you have to understand + + + align:start position:0% +in a system and you have to understand +the elements of that system so we're + + align:start position:0% +the elements of that system so we're + + + align:start position:0% +the elements of that system so we're +going to talk about that systems + + align:start position:0% +going to talk about that systems + + + align:start position:0% +going to talk about that systems +approach in next week's class and then + + align:start position:0% +approach in next week's class and then + + + align:start position:0% +approach in next week's class and then +I'll give you two kind of key tools to + + align:start position:0% +I'll give you two kind of key tools to + + + align:start position:0% +I'll give you two kind of key tools to +work with + + align:start position:0% +work with + + + align:start position:0% +work with +in other words based on the first couple + + align:start position:0% +in other words based on the first couple + + + align:start position:0% +in other words based on the first couple +of classes you're going to be able to + + align:start position:0% +of classes you're going to be able to + + + align:start position:0% +of classes you're going to be able to +look at another country at a state at a + + align:start position:0% +look at another country at a state at a + + + align:start position:0% +look at another country at a state at a +region and you're going to be able to + + align:start position:0% +region and you're going to be able to + + + align:start position:0% +region and you're going to be able to +see how you can evaluate + + align:start position:0% + + + + align:start position:0% + +that areas innovation system what are + + align:start position:0% +that areas innovation system what are + + + align:start position:0% +that areas innovation system what are +the factors you'd you look for what are + + align:start position:0% +the factors you'd you look for what are + + + align:start position:0% +the factors you'd you look for what are +the capabilities that you look for how + + align:start position:0% +the capabilities that you look for how + + + align:start position:0% +the capabilities that you look for how +do you assess them and then in + + align:start position:0% +do you assess them and then in + + + align:start position:0% +do you assess them and then in +particular at the end of next week's + + align:start position:0% +particular at the end of next week's + + + align:start position:0% +particular at the end of next week's +class how do you look at them as a + + align:start position:0% +class how do you look at them as a + + + align:start position:0% +class how do you look at them as a +system and then we'll take that + + align:start position:0% +system and then we'll take that + + + align:start position:0% +system and then we'll take that +framework and we're going to apply that + + align:start position:0% +framework and we're going to apply that + + + align:start position:0% +framework and we're going to apply that +framework and add pieces to it through + + align:start position:0% +framework and add pieces to it through + + + align:start position:0% +framework and add pieces to it through +the rest of the class so the next two + + align:start position:0% +the rest of the class so the next two + + + align:start position:0% +the rest of the class so the next two +classes are really about manufacturing + + align:start position:0% +classes are really about manufacturing + + + align:start position:0% +classes are really about manufacturing +so just in case you got the idea that + + align:start position:0% +so just in case you got the idea that + + + align:start position:0% +so just in case you got the idea that +this is just policy esoterica we're + + align:start position:0% +this is just policy esoterica we're + + + align:start position:0% +this is just policy esoterica we're +gonna have a very real dive and do some + + align:start position:0% +gonna have a very real dive and do some + + + align:start position:0% +gonna have a very real dive and do some +very real problems that are frankly at + + align:start position:0% +very real problems that are frankly at + + + align:start position:0% +very real problems that are frankly at +the heart of the political disruption + + align:start position:0% +the heart of the political disruption + + + align:start position:0% +the heart of the political disruption +that's going on now in the United States + + align:start position:0% +that's going on now in the United States + + + align:start position:0% +that's going on now in the United States +and elsewhere so we're gonna do two + + align:start position:0% +and elsewhere so we're gonna do two + + + align:start position:0% +and elsewhere so we're gonna do two +classes on that right so a deep very + + align:start position:0% +classes on that right so a deep very + + + align:start position:0% +classes on that right so a deep very +practical very real dive into a really + + align:start position:0% +practical very real dive into a really + + + align:start position:0% +practical very real dive into a really +important and very current innovation + + align:start position:0% +important and very current innovation + + + align:start position:0% +important and very current innovation +system problem and then we're gonna go + + align:start position:0% +system problem and then we're gonna go + + + align:start position:0% +system problem and then we're gonna go +back and pick up some pieces we started + + align:start position:0% +back and pick up some pieces we started + + + align:start position:0% +back and pick up some pieces we started +with at the first couple of classes so + + align:start position:0% +with at the first couple of classes so + + + align:start position:0% +with at the first couple of classes so +we're going to look hard at the u.s. + + align:start position:0% +we're going to look hard at the u.s. + + + align:start position:0% +we're going to look hard at the u.s. +innovation system particularly the + + align:start position:0% +innovation system particularly the + + + align:start position:0% +innovation system particularly the +federal pieces of it right the federal + + align:start position:0% +federal pieces of it right the federal + + + align:start position:0% +federal pieces of it right the federal +R&D agencies and organizations that are + + align:start position:0% +R&D agencies and organizations that are + + + align:start position:0% +R&D agencies and organizations that are +part of the u.s. innovation system + + align:start position:0% +part of the u.s. innovation system + + + align:start position:0% +part of the u.s. innovation system +research and development okay + + align:start position:0% +research and development okay + + + align:start position:0% +research and development okay +don't hesitate to ask questions by the + + align:start position:0% +don't hesitate to ask questions by the + + + align:start position:0% +don't hesitate to ask questions by the +way please you know bring those forward + + align:start position:0% +way please you know bring those forward + + + align:start position:0% +way please you know bring those forward +so we'll look at the research and + + align:start position:0% +so we'll look at the research and + + + align:start position:0% +so we'll look at the research and +development system it's done it's + + align:start position:0% +development system it's done it's + + + align:start position:0% +development system it's done it's +daunting + + align:start position:0% +daunting + + + align:start position:0% +daunting +Steff that is easier okay + + align:start position:0% +Steff that is easier okay + + + align:start position:0% +Steff that is easier okay +thanks Steph and you know where did it + + align:start position:0% +thanks Steph and you know where did it + + + align:start position:0% +thanks Steph and you know where did it +come from how does it think how is it + + align:start position:0% +come from how does it think how is it + + + align:start position:0% +come from how does it think how is it +organized what are its origins because + + align:start position:0% +organized what are its origins because + + + align:start position:0% +organized what are its origins because +worried MIT I'll give you a lot of + + align:start position:0% +worried MIT I'll give you a lot of + + + align:start position:0% +worried MIT I'll give you a lot of +insider and mighty stuff because MIT + + align:start position:0% +insider and mighty stuff because MIT + + + align:start position:0% +insider and mighty stuff because MIT +historically was involved in a lot of + + align:start position:0% +historically was involved in a lot of + + + align:start position:0% +historically was involved in a lot of +this so you'll collect some good MIT + + align:start position:0% +this so you'll collect some good MIT + + + align:start position:0% +this so you'll collect some good MIT +stories + + align:start position:0% +stories + + + align:start position:0% +stories +I hope particularly in that class but + + align:start position:0% +I hope particularly in that class but + + + align:start position:0% +I hope particularly in that class but +you know MIT greats like veneer Bush and + + align:start position:0% +you know MIT greats like veneer Bush and + + + align:start position:0% +you know MIT greats like veneer Bush and +Alfred Loomis will come up in that class + + align:start position:0% +Alfred Loomis will come up in that class + + + align:start position:0% +Alfred Loomis will come up in that class +then in the sixth class we're going to + + align:start position:0% +then in the sixth class we're going to + + + align:start position:0% +then in the sixth class we're going to +talk about kind of the major policy + + align:start position:0% +talk about kind of the major policy + + + align:start position:0% +talk about kind of the major policy +focus + + align:start position:0% +focus + + + align:start position:0% +focus +in science technology policy which is + + align:start position:0% +in science technology policy which is + + + align:start position:0% +in science technology policy which is +called the valley of death how do you + + align:start position:0% +called the valley of death how do you + + + align:start position:0% +called the valley of death how do you +get from the research side over to later + + align:start position:0% +get from the research side over to later + + + align:start position:0% +get from the research side over to later +stage development right and that's been + + align:start position:0% +stage development right and that's been + + + align:start position:0% +stage development right and that's been +the major policy emphasis in the u.s. + + align:start position:0% +the major policy emphasis in the u.s. + + + align:start position:0% +the major policy emphasis in the u.s. +system is a big chasm there a valley + + align:start position:0% +system is a big chasm there a valley + + + align:start position:0% +system is a big chasm there a valley +building the bridging mechanisms across + + align:start position:0% +building the bridging mechanisms across + + + align:start position:0% +building the bridging mechanisms across +it's been a big policy preoccupation so + + align:start position:0% +it's been a big policy preoccupation so + + + align:start position:0% +it's been a big policy preoccupation so +we'll dive into that literature and we + + align:start position:0% +we'll dive into that literature and we + + + align:start position:0% +we'll dive into that literature and we +will also look at the fact that the + + align:start position:0% +will also look at the fact that the + + + align:start position:0% +will also look at the fact that the +United States actually runs to + + align:start position:0% +United States actually runs to + + + align:start position:0% +United States actually runs to +innovation systems so we run the + + align:start position:0% +innovation systems so we run the + + + align:start position:0% +innovation systems so we run the +innovation system probably most of you + + align:start position:0% +innovation system probably most of you + + + align:start position:0% +innovation system probably most of you +are familiar with places like NSF right + + align:start position:0% +are familiar with places like NSF right + + + align:start position:0% +are familiar with places like NSF right +the Office of Science at the Department + + align:start position:0% +the Office of Science at the Department + + + align:start position:0% +the Office of Science at the Department +of Energy NIH right so that's the kind + + align:start position:0% +of Energy NIH right so that's the kind + + + align:start position:0% +of Energy NIH right so that's the kind +of civilian side but then there's a + + align:start position:0% +of civilian side but then there's a + + + align:start position:0% +of civilian side but then there's a +whole defense innovation system that + + align:start position:0% +whole defense innovation system that + + + align:start position:0% +whole defense innovation system that +it's organized very differently Lilly is + + align:start position:0% +it's organized very differently Lilly is + + + align:start position:0% +it's organized very differently Lilly is +not in our head because we spent time on + + align:start position:0% +not in our head because we spent time on + + + align:start position:0% +not in our head because we spent time on +this in the first class so we'll talk + + align:start position:0% +this in the first class so we'll talk + + + align:start position:0% +this in the first class so we'll talk +about that system too and kind of how + + align:start position:0% +about that system too and kind of how + + + align:start position:0% +about that system too and kind of how +that works and then all up until class + + align:start position:0% +that works and then all up until class + + + align:start position:0% +that works and then all up until class +seven we've been talking about + + align:start position:0% +seven we've been talking about + + + align:start position:0% +seven we've been talking about +innovation as though it's has to do with + + align:start position:0% +innovation as though it's has to do with + + + align:start position:0% +innovation as though it's has to do with +institutions but people innovate not + + align:start position:0% +institutions but people innovate not + + + align:start position:0% +institutions but people innovate not +institutions so innovation is owned by + + align:start position:0% +institutions so innovation is owned by + + + align:start position:0% +institutions so innovation is owned by +people it occurs in a very face-to-face + + align:start position:0% +people it occurs in a very face-to-face + + + align:start position:0% +people it occurs in a very face-to-face +environment right + + align:start position:0% +environment right + + + align:start position:0% +environment right +you can't just understand innovation by + + align:start position:0% +you can't just understand innovation by + + + align:start position:0% +you can't just understand innovation by +understanding the institutions that are + + align:start position:0% +understanding the institutions that are + + + align:start position:0% +understanding the institutions that are +sticking their hands into it in the end + + align:start position:0% +sticking their hands into it in the end + + + align:start position:0% +sticking their hands into it in the end +it's a people system and how do people + + align:start position:0% +it's a people system and how do people + + + align:start position:0% +it's a people system and how do people +what does innovation look like when + + align:start position:0% +what does innovation look like when + + + align:start position:0% +what does innovation look like when +people are running it at the + + align:start position:0% +people are running it at the + + + align:start position:0% +people are running it at the +face-to-face level and it turns out + + align:start position:0% +face-to-face level and it turns out + + + align:start position:0% +face-to-face level and it turns out +there's literature on this there's some + + align:start position:0% +there's literature on this there's some + + + align:start position:0% +there's literature on this there's some +rules that innovation groups tend to + + align:start position:0% +rules that innovation groups tend to + + + align:start position:0% +rules that innovation groups tend to +follow when they're undertaking their + + align:start position:0% +follow when they're undertaking their + + + align:start position:0% +follow when they're undertaking their +process of trying to get to a + + align:start position:0% +process of trying to get to a + + + align:start position:0% +process of trying to get to a +breakthrough so we'll look at the + + align:start position:0% +breakthrough so we'll look at the + + + align:start position:0% +breakthrough so we'll look at the +organization of innovation systems at + + align:start position:0% +organization of innovation systems at + + + align:start position:0% +organization of innovation systems at +the face-to-face level as well as the + + align:start position:0% +the face-to-face level as well as the + + + align:start position:0% +the face-to-face level as well as the +institutional level and that class you + + align:start position:0% +institutional level and that class you + + + align:start position:0% +institutional level and that class you +all will own because I'm gonna have you + + align:start position:0% +all will own because I'm gonna have you + + + align:start position:0% +all will own because I'm gonna have you +all present a group of you on great + + align:start position:0% +all present a group of you on great + + + align:start position:0% +all present a group of you on great +innovation groups and then we've got the + + align:start position:0% +innovation groups and then we've got the + + + align:start position:0% +innovation groups and then we've got the +foundations all set and we're gonna + + align:start position:0% +foundations all set and we're gonna + + + align:start position:0% +foundations all set and we're gonna +start to look at particular segments so + + align:start position:0% +start to look at particular segments so + + + align:start position:0% +start to look at particular segments so +we'll take a deep dive into DARPA the + + align:start position:0% +we'll take a deep dive into DARPA the + + + align:start position:0% +we'll take a deep dive into DARPA the +Defense Advanced Research + + align:start position:0% +Defense Advanced Research + + + align:start position:0% +Defense Advanced Research +Church agency and its innovation model + + align:start position:0% +Church agency and its innovation model + + + align:start position:0% +Church agency and its innovation model +so that'll be kind of a case study we're + + align:start position:0% +so that'll be kind of a case study we're + + + align:start position:0% +so that'll be kind of a case study we're +gonna take a close look at at energy + + align:start position:0% +gonna take a close look at at energy + + + align:start position:0% +gonna take a close look at at energy +technology and here Martha will help us + + align:start position:0% +technology and here Martha will help us + + + align:start position:0% +technology and here Martha will help us +get through the class cuz she'll know + + align:start position:0% +get through the class cuz she'll know + + + align:start position:0% +get through the class cuz she'll know +much more than me and we're gonna look + + align:start position:0% +much more than me and we're gonna look + + + align:start position:0% +much more than me and we're gonna look +very closely at the life science + + align:start position:0% +very closely at the life science + + + align:start position:0% +very closely at the life science +innovation system that on the federal + + align:start position:0% +innovation system that on the federal + + + align:start position:0% +innovation system that on the federal +side is led by the National Institutes + + align:start position:0% +side is led by the National Institutes + + + align:start position:0% +side is led by the National Institutes +of Health and some of the big challenges + + align:start position:0% +of Health and some of the big challenges + + + align:start position:0% +of Health and some of the big challenges +in that system we're gonna develop an + + align:start position:0% +in that system we're gonna develop an + + + align:start position:0% +in that system we're gonna develop an +idea of how do legacy sectors innovate + + align:start position:0% +idea of how do legacy sectors innovate + + + align:start position:0% +idea of how do legacy sectors innovate +right because you know the computing + + align:start position:0% +right because you know the computing + + + align:start position:0% +right because you know the computing +revolution was brought about by a new + + align:start position:0% +revolution was brought about by a new + + + align:start position:0% +revolution was brought about by a new +frontier creating a new frontier + + align:start position:0% +frontier creating a new frontier + + + align:start position:0% +frontier creating a new frontier +territory and innovation but most of the + + align:start position:0% +territory and innovation but most of the + + + align:start position:0% +territory and innovation but most of the +economy more than 80% is owned by these + + align:start position:0% +economy more than 80% is owned by these + + + align:start position:0% +economy more than 80% is owned by these +established sectors and it's much harder + + align:start position:0% +established sectors and it's much harder + + + align:start position:0% +established sectors and it's much harder +to bring innovation into those sectors + + align:start position:0% +to bring innovation into those sectors + + + align:start position:0% +to bring innovation into those sectors +so energy is like the poster child for + + align:start position:0% +so energy is like the poster child for + + + align:start position:0% +so energy is like the poster child for +that problem and we'll take a real look + + align:start position:0% +that problem and we'll take a real look + + + align:start position:0% +that problem and we'll take a real look +at that and then at the close the class + + align:start position:0% +at that and then at the close the class + + + align:start position:0% +at that and then at the close the class +we're gonna do a couple of I think more + + align:start position:0% +we're gonna do a couple of I think more + + + align:start position:0% +we're gonna do a couple of I think more +fun and interesting you know out of the + + align:start position:0% +fun and interesting you know out of the + + + align:start position:0% +fun and interesting you know out of the +blue categories so we're gonna look at + + align:start position:0% +blue categories so we're gonna look at + + + align:start position:0% +blue categories so we're gonna look at +the talent base and science and + + align:start position:0% +the talent base and science and + + + align:start position:0% +the talent base and science and +technology education and all the + + align:start position:0% +technology education and all the + + + align:start position:0% +technology education and all the +challenge is embedded in that developing + + align:start position:0% +challenge is embedded in that developing + + + align:start position:0% +challenge is embedded in that developing +as strong as in detail at base and then + + align:start position:0% +as strong as in detail at base and then + + + align:start position:0% +as strong as in detail at base and then +we're gonna take a look at what we could + + align:start position:0% +we're gonna take a look at what we could + + + align:start position:0% +we're gonna take a look at what we could +call the future of work so are you gonna + + align:start position:0% +call the future of work so are you gonna + + + align:start position:0% +call the future of work so are you gonna +have any jobs right are you gonna be + + align:start position:0% +have any jobs right are you gonna be + + + align:start position:0% +have any jobs right are you gonna be +displaced by MIT developed robotics + + align:start position:0% +displaced by MIT developed robotics + + + align:start position:0% +displaced by MIT developed robotics +right that will be you aren't don't + + align:start position:0% +right that will be you aren't don't + + + align:start position:0% +right that will be you aren't don't +worry but that'll be one of the + + align:start position:0% +worry but that'll be one of the + + + align:start position:0% +worry but that'll be one of the +challenges that we're going to look at + + align:start position:0% +challenges that we're going to look at + + + align:start position:0% +challenges that we're going to look at +now tell me your name so I get to know + + align:start position:0% +now tell me your name so I get to know + + + align:start position:0% +now tell me your name so I get to know +everybody + + align:start position:0% + + + + align:start position:0% + +okay Martina you know we'll look at I + + align:start position:0% +okay Martina you know we'll look at I + + + align:start position:0% +okay Martina you know we'll look at I +tell you who will look at will look at + + align:start position:0% +tell you who will look at will look at + + + align:start position:0% +tell you who will look at will look at +the kind of techno dystopia movement + + align:start position:0% +the kind of techno dystopia movement + + + align:start position:0% +the kind of techno dystopia movement +which Erik Brynjolfsson and Andrew + + align:start position:0% +which Erik Brynjolfsson and Andrew + + + align:start position:0% +which Erik Brynjolfsson and Andrew +McAfee at Sloan have been doing a lot of + + align:start position:0% +McAfee at Sloan have been doing a lot of + + + align:start position:0% +McAfee at Sloan have been doing a lot of +work on and that's you know IT is going + + align:start position:0% +work on and that's you know IT is going + + + align:start position:0% +work on and that's you know IT is going +to replace + + align:start position:0% +to replace + + + align:start position:0% +to replace +a lot of work theory we're gonna look at + + align:start position:0% +a lot of work theory we're gonna look at + + + align:start position:0% +a lot of work theory we're gonna look at +David otter + + align:start position:0% +David otter + + + align:start position:0% +David otter +who's a wonderful MIT economist and + + align:start position:0% +who's a wonderful MIT economist and + + + align:start position:0% +who's a wonderful MIT economist and +we'll read several things from David but + + align:start position:0% +we'll read several things from David but + + + align:start position:0% +we'll read several things from David but +he's looking at all kinds of an economic + + align:start position:0% +he's looking at all kinds of an economic + + + align:start position:0% +he's looking at all kinds of an economic +effects on job creation including from + + align:start position:0% +effects on job creation including from + + + align:start position:0% +effects on job creation including from +manufacturing and you know we're gonna + + align:start position:0% +manufacturing and you know we're gonna + + + align:start position:0% +manufacturing and you know we're gonna +look at some studies that try to take a + + align:start position:0% +look at some studies that try to take a + + + align:start position:0% +look at some studies that try to take a +deep dive into you know how much work is + + align:start position:0% +deep dive into you know how much work is + + + align:start position:0% +deep dive into you know how much work is +actually gonna be displaced right and + + align:start position:0% +actually gonna be displaced right and + + + align:start position:0% +actually gonna be displaced right and +there's a fairly interesting new OECD + + align:start position:0% +there's a fairly interesting new OECD + + + align:start position:0% +there's a fairly interesting new OECD +study that came out this summer that + + align:start position:0% +study that came out this summer that + + + align:start position:0% +study that came out this summer that +indicates it's not going to be that bad + + align:start position:0% +indicates it's not going to be that bad + + + align:start position:0% +indicates it's not going to be that bad +so we're gonna look at all these kinds + + align:start position:0% +so we're gonna look at all these kinds + + + align:start position:0% +so we're gonna look at all these kinds +of issues and kind of play them out but + + align:start position:0% +of issues and kind of play them out but + + + align:start position:0% +of issues and kind of play them out but +I think it'll be you know particularly + + align:start position:0% +I think it'll be you know particularly + + + align:start position:0% +I think it'll be you know particularly +interesting and a kind of challenging + + align:start position:0% +interesting and a kind of challenging + + + align:start position:0% +interesting and a kind of challenging +session one more thing we'll do as David + + align:start position:0% +session one more thing we'll do as David + + + align:start position:0% +session one more thing we'll do as David +Mindell who's teaches at STS who is a + + align:start position:0% +Mindell who's teaches at STS who is a + + + align:start position:0% +Mindell who's teaches at STS who is a +wonderful technology historian but also + + align:start position:0% +wonderful technology historian but also + + + align:start position:0% +wonderful technology historian but also +a terrific engineer so David is on leave + + align:start position:0% +a terrific engineer so David is on leave + + + align:start position:0% +a terrific engineer so David is on leave +from MIT this semester because he's + + align:start position:0% +from MIT this semester because he's + + + align:start position:0% +from MIT this semester because he's +doing his robotics startup but he has a + + align:start position:0% +doing his robotics startup but he has a + + + align:start position:0% +doing his robotics startup but he has a +book called our robots ourselves + + align:start position:0% +book called our robots ourselves + + + align:start position:0% +book called our robots ourselves +and he takes a really deep look if + + align:start position:0% +and he takes a really deep look if + + + align:start position:0% +and he takes a really deep look if +robotics in a way is the most + + align:start position:0% +robotics in a way is the most + + + align:start position:0% +robotics in a way is the most +threatening entry to human work what + + align:start position:0% +threatening entry to human work what + + + align:start position:0% +threatening entry to human work what +does that actually look like right what + + align:start position:0% +does that actually look like right what + + + align:start position:0% +does that actually look like right what +is actually going on and he comes up + + align:start position:0% +is actually going on and he comes up + + + align:start position:0% +is actually going on and he comes up +with a thesis that's much more about + + align:start position:0% +with a thesis that's much more about + + + align:start position:0% +with a thesis that's much more about +assistive robotics and Co bot X then + + align:start position:0% +assistive robotics and Co bot X then + + + align:start position:0% +assistive robotics and Co bot X then +about people displacement so we'll look + + align:start position:0% +about people displacement so we'll look + + + align:start position:0% +about people displacement so we'll look +at all this stuff and try and lay it out + + align:start position:0% +at all this stuff and try and lay it out + + + align:start position:0% +at all this stuff and try and lay it out +anything anything so far questions so + + align:start position:0% +anything anything so far questions so + + + align:start position:0% +anything anything so far questions so +far yeah so we're gonna do snapshots on + + align:start position:0% +far yeah so we're gonna do snapshots on + + + align:start position:0% +far yeah so we're gonna do snapshots on +international issues kind of throughout + + align:start position:0% +international issues kind of throughout + + + align:start position:0% +international issues kind of throughout +so the basic focus will be in the US but + + align:start position:0% +so the basic focus will be in the US but + + + align:start position:0% +so the basic focus will be in the US but +Matt coming back to your question + + align:start position:0% +Matt coming back to your question + + + align:start position:0% +Matt coming back to your question +there'll be a lot of underlying + + align:start position:0% +there'll be a lot of underlying + + + align:start position:0% +there'll be a lot of underlying +questions about how economic growth + + align:start position:0% +questions about how economic growth + + + align:start position:0% +questions about how economic growth +innovation based growth works that's + + align:start position:0% +innovation based growth works that's + + + align:start position:0% +innovation based growth works that's +going to have a lot more applicability + + align:start position:0% +going to have a lot more applicability + + + align:start position:0% +going to have a lot more applicability +worldwide including the development of + + align:start position:0% +worldwide including the development of + + + align:start position:0% +worldwide including the development of +developing world so you're gonna get a + + align:start position:0% +developing world so you're gonna get a + + + align:start position:0% +developing world so you're gonna get a +toolset that will enable you + + align:start position:0% +toolset that will enable you + + + align:start position:0% +toolset that will enable you +to look at innovation much more broadly + + align:start position:0% +to look at innovation much more broadly + + + align:start position:0% +to look at innovation much more broadly +than just the US you're gonna pick up a + + align:start position:0% +than just the US you're gonna pick up a + + + align:start position:0% +than just the US you're gonna pick up a +lot of pieces about the US but it's a + + align:start position:0% +lot of pieces about the US but it's a + + + align:start position:0% +lot of pieces about the US but it's a +much broader toolset than that which I + + align:start position:0% +much broader toolset than that which I + + + align:start position:0% +much broader toolset than that which I +think you'll be able to apply and we'll + + align:start position:0% +think you'll be able to apply and we'll + + + align:start position:0% +think you'll be able to apply and we'll +have a number of readings that will pull + + align:start position:0% +have a number of readings that will pull + + + align:start position:0% +have a number of readings that will pull +us into the international issues what + + align:start position:0% +us into the international issues what + + + align:start position:0% +us into the international issues what +else our team I'm always open to current + + align:start position:0% +else our team I'm always open to current + + + align:start position:0% +else our team I'm always open to current +events so when we talk about + + align:start position:0% +events so when we talk about + + + align:start position:0% +events so when we talk about +manufacturing I'll try and give you a + + align:start position:0% +manufacturing I'll try and give you a + + + align:start position:0% +manufacturing I'll try and give you a +backdrop on some of that so that's + + align:start position:0% +backdrop on some of that so that's + + + align:start position:0% +backdrop on some of that so that's +that's the third class and you know it's + + align:start position:0% +that's the third class and you know it's + + + align:start position:0% +that's the third class and you know it's +been a lot of social disruption in the + + align:start position:0% +been a lot of social disruption in the + + + align:start position:0% +been a lot of social disruption in the +US and we'll try and through a reading + + align:start position:0% +US and we'll try and through a reading + + + align:start position:0% +US and we'll try and through a reading +but we'll talk about David autor and + + align:start position:0% +but we'll talk about David autor and + + + align:start position:0% +but we'll talk about David autor and +some of his work and findings in that + + align:start position:0% +some of his work and findings in that + + + align:start position:0% +some of his work and findings in that +area in particular and there'll be a lot + + align:start position:0% +area in particular and there'll be a lot + + + align:start position:0% +area in particular and there'll be a lot +of stories developing as the year goes + + align:start position:0% +of stories developing as the year goes + + + align:start position:0% +of stories developing as the year goes +on I know anything else to start yeah + + align:start position:0% +on I know anything else to start yeah + + + align:start position:0% +on I know anything else to start yeah +fleshie Rasheed right yeah it's good you + + align:start position:0% +fleshie Rasheed right yeah it's good you + + + align:start position:0% +fleshie Rasheed right yeah it's good you +bet you bet none of this stuff is locked + + align:start position:0% +bet you bet none of this stuff is locked + + + align:start position:0% +bet you bet none of this stuff is locked +in stone you know I hope all of you will + + align:start position:0% +in stone you know I hope all of you will + + + align:start position:0% +in stone you know I hope all of you will +do startups at some point in your career + + align:start position:0% +do startups at some point in your career + + + align:start position:0% +do startups at some point in your career +I hope all of you will be involved in + + align:start position:0% +I hope all of you will be involved in + + + align:start position:0% +I hope all of you will be involved in +innovation policy and issues and part of + + align:start position:0% +innovation policy and issues and part of + + + align:start position:0% +innovation policy and issues and part of +the tool set you're going to get is how + + align:start position:0% +the tool set you're going to get is how + + + align:start position:0% +the tool set you're going to get is how +to think about those innovation systems + + align:start position:0% +to think about those innovation systems + + + align:start position:0% +to think about those innovation systems +and how to think about organizing them + + align:start position:0% +and how to think about organizing them + + + align:start position:0% +and how to think about organizing them +in an optimal way if anything that's the + + align:start position:0% +in an optimal way if anything that's the + + + align:start position:0% +in an optimal way if anything that's the +key thing I won't want to convey in this + + align:start position:0% +key thing I won't want to convey in this + + + align:start position:0% +key thing I won't want to convey in this +course so then when you're running this + + align:start position:0% +course so then when you're running this + + + align:start position:0% +course so then when you're running this +country you got a you got an agenda + + align:start position:0% +country you got a you got an agenda + + + align:start position:0% +country you got a you got an agenda +ready to go anything else + + align:start position:0% + + + + align:start position:0% + +alright so I'm gonna do more talking in + + align:start position:0% +alright so I'm gonna do more talking in + + + align:start position:0% +alright so I'm gonna do more talking in +this class I'll do less talking in + + align:start position:0% +this class I'll do less talking in + + + align:start position:0% +this class I'll do less talking in +future classes hold me to that but let + + align:start position:0% +future classes hold me to that but let + + + align:start position:0% +future classes hold me to that but let +me kind of summarize what we're gonna + + align:start position:0% +me kind of summarize what we're gonna + + + align:start position:0% +me kind of summarize what we're gonna +see in today's class so we're gonna talk + + align:start position:0% +see in today's class so we're gonna talk + + + align:start position:0% +see in today's class so we're gonna talk +about Robert Solow and his contribution + + align:start position:0% +about Robert Solow and his contribution + + + align:start position:0% +about Robert Solow and his contribution +is to think about a critical factor in + + align:start position:0% +is to think about a critical factor in + + + align:start position:0% +is to think about a critical factor in +innovation right a direct innovation + + align:start position:0% +innovation right a direct innovation + + + align:start position:0% +innovation right a direct innovation +factor which he refers to as + + align:start position:0% +factor which he refers to as + + + align:start position:0% +factor which he refers to as +technological and related innovation so + + align:start position:0% +technological and related innovation so + + + align:start position:0% +technological and related innovation so +that's a term that I want you all to + + align:start position:0% +that's a term that I want you all to + + + align:start position:0% +that's a term that I want you all to +recall technological and related + + align:start position:0% +recall technological and related + + + align:start position:0% +recall technological and related +innovation we're gonna use that a lot + + align:start position:0% +innovation we're gonna use that a lot + + + align:start position:0% +innovation we're gonna use that a lot +and we'll talk in a minute about what it + + align:start position:0% +and we'll talk in a minute about what it + + + align:start position:0% +and we'll talk in a minute about what it +means and then we're gonna talk about + + align:start position:0% +means and then we're gonna talk about + + + align:start position:0% +means and then we're gonna talk about +another great growth economist Paul + + align:start position:0% +another great growth economist Paul + + + align:start position:0% +another great growth economist Paul +Romer he was in MIT for about a year and + + align:start position:0% +Romer he was in MIT for about a year and + + + align:start position:0% +Romer he was in MIT for about a year and +then ran out he's a character and we'll + + align:start position:0% +then ran out he's a character and we'll + + + align:start position:0% +then ran out he's a character and we'll +talk about him too but he comes up with + + align:start position:0% +talk about him too but he comes up with + + + align:start position:0% +talk about him too but he comes up with +our second direct innovation factor + + align:start position:0% +our second direct innovation factor + + + align:start position:0% +our second direct innovation factor +human capital engaged in research and + + align:start position:0% +human capital engaged in research and + + + align:start position:0% +human capital engaged in research and +we'll talk about what that means and + + align:start position:0% +we'll talk about what that means and + + + align:start position:0% +we'll talk about what that means and +then third do these factors actually + + align:start position:0% +then third do these factors actually + + + align:start position:0% +then third do these factors actually +make sense + + align:start position:0% +make sense + + + align:start position:0% +make sense +so Dale Jorgenson is a Harvard economics + + align:start position:0% +so Dale Jorgenson is a Harvard economics + + + align:start position:0% +so Dale Jorgenson is a Harvard economics +professor of note another great growth + + align:start position:0% +professor of note another great growth + + + align:start position:0% +professor of note another great growth +economist then he takes a deep dive into + + align:start position:0% +economist then he takes a deep dive into + + + align:start position:0% +economist then he takes a deep dive into +the IT revolution of the 90s and the + + align:start position:0% +the IT revolution of the 90s and the + + + align:start position:0% +the IT revolution of the 90s and the +period leading up to that and he + + align:start position:0% +period leading up to that and he + + + align:start position:0% +period leading up to that and he +essentially concludes yeah this was + + align:start position:0% +essentially concludes yeah this was + + + align:start position:0% +essentially concludes yeah this was +technological driven innovation based + + align:start position:0% +technological driven innovation based + + + align:start position:0% +technological driven innovation based +growth it drove a huge growth in the + + align:start position:0% +growth it drove a huge growth in the + + + align:start position:0% +growth it drove a huge growth in the +economy and then we'll have fun with a + + align:start position:0% +economy and then we'll have fun with a + + + align:start position:0% +economy and then we'll have fun with a +little study by Merrill Lynch which is + + align:start position:0% +little study by Merrill Lynch which is + + + align:start position:0% +little study by Merrill Lynch which is +an investor's look at innovation and how + + align:start position:0% +an investor's look at innovation and how + + + align:start position:0% +an investor's look at innovation and how +do investors think about investing in + + align:start position:0% +do investors think about investing in + + + align:start position:0% +do investors think about investing in +innovation and then we'll look at some I + + align:start position:0% +innovation and then we'll look at some I + + + align:start position:0% +innovation and then we'll look at some I +asked you all to look at NSF indicators + + align:start position:0% +asked you all to look at NSF indicators + + + align:start position:0% +asked you all to look at NSF indicators +I'll explain what that is in a bit but + + align:start position:0% +I'll explain what that is in a bit but + + + align:start position:0% +I'll explain what that is in a bit but +we'll look at some ways of looking at + + align:start position:0% +we'll look at some ways of looking at + + + align:start position:0% +we'll look at some ways of looking at +those two facing innovation factors the + + align:start position:0% +those two facing innovation factors the + + + align:start position:0% +those two facing innovation factors the +technology R&D factor the talent factor + + align:start position:0% +technology R&D factor the talent factor + + + align:start position:0% +technology R&D factor the talent factor +and where do those if you look at those + + align:start position:0% +and where do those if you look at those + + + align:start position:0% +and where do those if you look at those +what do those look like in the US so + + align:start position:0% +what do those look like in the US so + + + align:start position:0% +what do those look like in the US so +part one here is you know the + + align:start position:0% +part one here is you know the + + + align:start position:0% +part one here is you know the +kind of fundamental factors of + + align:start position:0% +kind of fundamental factors of + + + align:start position:0% +kind of fundamental factors of +innovation but let me get some general + + align:start position:0% +innovation but let me get some general + + + align:start position:0% +innovation but let me get some general +terms on the table and I will post by + + align:start position:0% +terms on the table and I will post by + + + align:start position:0% +terms on the table and I will post by +the way the lectures after on the + + align:start position:0% +the way the lectures after on the + + + align:start position:0% +the way the lectures after on the +stellar website so you all have access + + align:start position:0% +stellar website so you all have access + + + align:start position:0% +stellar website so you all have access +to them but there's some terms that will + + align:start position:0% +to them but there's some terms that will + + + align:start position:0% +to them but there's some terms that will +recur here and you no need to memorize + + align:start position:0% +recur here and you no need to memorize + + + align:start position:0% +recur here and you no need to memorize +them now but they'll be you know posted + + align:start position:0% +them now but they'll be you know posted + + + align:start position:0% +them now but they'll be you know posted +today or tomorrow so science science + + align:start position:0% +today or tomorrow so science science + + + align:start position:0% +today or tomorrow so science science +evolved as a way of understanding the + + align:start position:0% +evolved as a way of understanding the + + + align:start position:0% +evolved as a way of understanding the +natural world it came out of natural + + align:start position:0% +natural world it came out of natural + + + align:start position:0% +natural world it came out of natural +philosophy it's an 18th 19th century + + align:start position:0% +philosophy it's an 18th 19th century + + + align:start position:0% +philosophy it's an 18th 19th century +kind of conceptual framework it is + + align:start position:0% +kind of conceptual framework it is + + + align:start position:0% +kind of conceptual framework it is +observational at heart it observes the + + align:start position:0% +observational at heart it observes the + + + align:start position:0% +observational at heart it observes the +natural world and attempts to understand + + align:start position:0% +natural world and attempts to understand + + + align:start position:0% +natural world and attempts to understand +how it's put together and it's organized + + align:start position:0% +how it's put together and it's organized + + + align:start position:0% +how it's put together and it's organized +around discovery about that natural + + align:start position:0% +around discovery about that natural + + + align:start position:0% +around discovery about that natural +world and it's order technology is + + align:start position:0% +world and it's order technology is + + + align:start position:0% +world and it's order technology is +really different it is a system to + + align:start position:0% +really different it is a system to + + + align:start position:0% +really different it is a system to +organize scientific and technical + + align:start position:0% +organize scientific and technical + + + align:start position:0% +organize scientific and technical +knowledge to go after a more practical + + align:start position:0% +knowledge to go after a more practical + + + align:start position:0% +knowledge to go after a more practical +purpose and the system's includes the + + align:start position:0% +purpose and the system's includes the + + + align:start position:0% +purpose and the system's includes the +technical advance plus models to + + align:start position:0% +technical advance plus models to + + + align:start position:0% +technical advance plus models to +implement that advance so you move from + + align:start position:0% +implement that advance so you move from + + + align:start position:0% +implement that advance so you move from +observation to implementation right and + + align:start position:0% +observation to implementation right and + + + align:start position:0% +observation to implementation right and +this is obviously the historical + + align:start position:0% +this is obviously the historical + + + align:start position:0% +this is obviously the historical +boundary between science and engineering + + align:start position:0% +boundary between science and engineering + + + align:start position:0% +boundary between science and engineering +right and research another term we'll + + align:start position:0% +right and research another term we'll + + + align:start position:0% +right and research another term we'll +use constantly means increasing the + + align:start position:0% +use constantly means increasing the + + + align:start position:0% +use constantly means increasing the +scientific or technical knowledge or + + align:start position:0% +scientific or technical knowledge or + + + align:start position:0% +scientific or technical knowledge or +both right so research can pursue either + + align:start position:0% +both right so research can pursue either + + + align:start position:0% +both right so research can pursue either +of these historic ends or both + + align:start position:0% +of these historic ends or both + + + align:start position:0% +of these historic ends or both +simultaneously invention is about + + align:start position:0% +simultaneously invention is about + + + align:start position:0% +simultaneously invention is about +applying research knowledge to create a + + align:start position:0% +applying research knowledge to create a + + + align:start position:0% +applying research knowledge to create a +practical idea or device in a vention is + + align:start position:0% +practical idea or device in a vention is + + + align:start position:0% +practical idea or device in a vention is +really different than innovation right + + align:start position:0% +really different than innovation right + + + align:start position:0% +really different than innovation right +innovation is built on scientific + + align:start position:0% +innovation is built on scientific + + + align:start position:0% +innovation is built on scientific +discovery and on breakthrough invention + + align:start position:0% +discovery and on breakthrough invention + + + align:start position:0% +discovery and on breakthrough invention +or inventions + + align:start position:0% +or inventions + + + align:start position:0% +or inventions +but it is the system of research + + align:start position:0% +but it is the system of research + + + align:start position:0% +but it is the system of research +invention development that uses both + + align:start position:0% +invention development that uses both + + + align:start position:0% +invention development that uses both +scientific background scientific + + align:start position:0% +scientific background scientific + + + align:start position:0% +scientific background scientific +knowledge and technology knowledge to + + align:start position:0% +knowledge and technology knowledge to + + + align:start position:0% +knowledge and technology knowledge to +lead to the implementation and + + align:start position:0% +lead to the implementation and + + + align:start position:0% +lead to the implementation and +widespread applicability of you know a + + align:start position:0% +widespread applicability of you know a + + + align:start position:0% +widespread applicability of you know a +technology area right so typically in + + align:start position:0% +technology area right so typically in + + + align:start position:0% +technology area right so typically in +our society that means commercialization + + align:start position:0% +our society that means commercialization + + + align:start position:0% +our society that means commercialization +so this class is about this right that's + + align:start position:0% +so this class is about this right that's + + + align:start position:0% +so this class is about this right that's +the stage we're most focused on but + + align:start position:0% +the stage we're most focused on but + + + align:start position:0% +the stage we're most focused on but +remember all the input above that that + + align:start position:0% +remember all the input above that that + + + align:start position:0% +remember all the input above that that +goes into this now an innovation system + + align:start position:0% +goes into this now an innovation system + + + align:start position:0% +goes into this now an innovation system +we talked about this briefly before is + + align:start position:0% +we talked about this briefly before is + + + align:start position:0% +we talked about this briefly before is +the ecosystem for developing innovation + + align:start position:0% +the ecosystem for developing innovation + + + align:start position:0% +the ecosystem for developing innovation +and as we discussed briefly it operates + + align:start position:0% +and as we discussed briefly it operates + + + align:start position:0% +and as we discussed briefly it operates +at at least two levels it operates at + + align:start position:0% +at at least two levels it operates at + + + align:start position:0% +at at least two levels it operates at +the institutional level of supporting + + align:start position:0% +the institutional level of supporting + + + align:start position:0% +the institutional level of supporting +the development of the inventions and + + align:start position:0% +the development of the inventions and + + + align:start position:0% +the development of the inventions and +discovery that go into innovation but it + + align:start position:0% +discovery that go into innovation but it + + + align:start position:0% +discovery that go into innovation but it +also operates at the personal + + align:start position:0% +also operates at the personal + + + align:start position:0% +also operates at the personal +face-to-face level right because in the + + align:start position:0% +face-to-face level right because in the + + + align:start position:0% +face-to-face level right because in the +end people you all innovate not some + + align:start position:0% +end people you all innovate not some + + + align:start position:0% +end people you all innovate not some +fancy institution innovation wave theory + + align:start position:0% +fancy institution innovation wave theory + + + align:start position:0% +fancy institution innovation wave theory +okay and economics this is called Condry + + align:start position:0% +okay and economics this is called Condry + + + align:start position:0% +okay and economics this is called Condry +F theory and we'll talk more about this + + align:start position:0% +F theory and we'll talk more about this + + + align:start position:0% +F theory and we'll talk more about this +you know as the class goes on but let me + + align:start position:0% +you know as the class goes on but let me + + + align:start position:0% +you know as the class goes on but let me +just give you a kind of a snapshot on + + align:start position:0% +just give you a kind of a snapshot on + + + align:start position:0% +just give you a kind of a snapshot on +what I'm talking about innovation tends + + align:start position:0% +what I'm talking about innovation tends + + + align:start position:0% +what I'm talking about innovation tends +to come in a wave and in your lifetime + + align:start position:0% +to come in a wave and in your lifetime + + + align:start position:0% +to come in a wave and in your lifetime +the big wave has been the IT revolution + + align:start position:0% +the big wave has been the IT revolution + + + align:start position:0% +the big wave has been the IT revolution +right if we if we were born in 1800 well + + align:start position:0% +right if we if we were born in 1800 well + + + align:start position:0% +right if we if we were born in 1800 well +roads right would be like a big + + align:start position:0% +roads right would be like a big + + + align:start position:0% +roads right would be like a big +innovation wave early Telegraph based + + align:start position:0% +innovation wave early Telegraph based + + + align:start position:0% +innovation wave early Telegraph based +communication would be a big innovation + + align:start position:0% +communication would be a big innovation + + + align:start position:0% +communication would be a big innovation +wave right electricity would be a big + + align:start position:0% +wave right electricity would be a big + + + align:start position:0% +wave right electricity would be a big +innovation with right and you tend to + + align:start position:0% +innovation with right and you tend to + + + align:start position:0% +innovation with right and you tend to +have a core technology advance you pile + + align:start position:0% +have a core technology advance you pile + + + align:start position:0% +have a core technology advance you pile +on applications and it begins to move + + align:start position:0% +on applications and it begins to move + + + align:start position:0% +on applications and it begins to move +through an entire society and in effect + + align:start position:0% +through an entire society and in effect + + + align:start position:0% +through an entire society and in effect +the whole society and to some extent the + + align:start position:0% +the whole society and to some extent the + + + align:start position:0% +the whole society and to some extent the +technology drives the nature of the + + align:start position:0% +technology drives the nature of the + + + align:start position:0% +technology drives the nature of the +society so that's what Karl Marx + + align:start position:0% +society so that's what Karl Marx + + + align:start position:0% +society so that's what Karl Marx +believed that's called determinism right + + align:start position:0% +believed that's called determinism right + + + align:start position:0% +believed that's called determinism right +that the technology plays a determinist + + align:start position:0% +that the technology plays a determinist + + + align:start position:0% +that the technology plays a determinist +stick role in the organization of + + align:start position:0% +stick role in the organization of + + + align:start position:0% +stick role in the organization of +society so it's big it is very big it's + + align:start position:0% +society so it's big it is very big it's + + + align:start position:0% +society so it's big it is very big it's +not just a pile of new technology stuff + + align:start position:0% +not just a pile of new technology stuff + + + align:start position:0% +not just a pile of new technology stuff +it is fundamentally changing the way in + + align:start position:0% +it is fundamentally changing the way in + + + align:start position:0% +it is fundamentally changing the way in +which the society is organized as well + + align:start position:0% +which the society is organized as well + + + align:start position:0% +which the society is organized as well +so that's also part of these innovation + + align:start position:0% +so that's also part of these innovation + + + align:start position:0% +so that's also part of these innovation +ways okay so a wave hits an economy + + align:start position:0% +ways okay so a wave hits an economy + + + align:start position:0% +ways okay so a wave hits an economy +takes a long time to grow eventually it + + align:start position:0% +takes a long time to grow eventually it + + + align:start position:0% +takes a long time to grow eventually it +scales up and affects a good part of the + + align:start position:0% +scales up and affects a good part of the + + + align:start position:0% +scales up and affects a good part of the +economy in any given time eventually you + + align:start position:0% +economy in any given time eventually you + + + align:start position:0% +economy in any given time eventually you +run out of the technology menu and it + + align:start position:0% +run out of the technology menu and it + + + align:start position:0% +run out of the technology menu and it +stabilizes right but it doesn't + + align:start position:0% +stabilizes right but it doesn't + + + align:start position:0% +stabilizes right but it doesn't +disappear it creates a new plateau in + + align:start position:0% +disappear it creates a new plateau in + + + align:start position:0% +disappear it creates a new plateau in +your economy and then you do another + + align:start position:0% +your economy and then you do another + + + align:start position:0% +your economy and then you do another +wave yeah let me see if there's I know + + align:start position:0% +wave yeah let me see if there's I know + + + align:start position:0% +wave yeah let me see if there's I know +is there any chalk down at that end + + align:start position:0% +is there any chalk down at that end + + + align:start position:0% +is there any chalk down at that end +Martha I don't see any it's all right oh + + align:start position:0% +Martha I don't see any it's all right oh + + + align:start position:0% +Martha I don't see any it's all right oh +there is great we'll come back to this + + align:start position:0% +there is great we'll come back to this + + + align:start position:0% +there is great we'll come back to this +but it's an important enough idea so + + align:start position:0% +but it's an important enough idea so + + + align:start position:0% +but it's an important enough idea so +there's a slow build-up and then there's + + align:start position:0% +there's a slow build-up and then there's + + + align:start position:0% +there's a slow build-up and then there's +a rapid buildup then there's a bubble + + align:start position:0% +a rapid buildup then there's a bubble + + + align:start position:0% +a rapid buildup then there's a bubble +then there's slower scaling and then + + align:start position:0% +then there's slower scaling and then + + + align:start position:0% +then there's slower scaling and then +eventually you reach technological + + align:start position:0% +eventually you reach technological + + + align:start position:0% +eventually you reach technological +maturity right sort of three scales this + + align:start position:0% +maturity right sort of three scales this + + + align:start position:0% +maturity right sort of three scales this +is where the bubble is right so the IT + + align:start position:0% +is where the bubble is right so the IT + + + align:start position:0% +is where the bubble is right so the IT +wave right somebody I don't know where + + align:start position:0% +wave right somebody I don't know where + + + align:start position:0% +wave right somebody I don't know where +this starts maybe it starts with Babbage + + align:start position:0% +this starts maybe it starts with Babbage + + + align:start position:0% +this starts maybe it starts with Babbage +in the 19th century right but let's + + align:start position:0% +in the 19th century right but let's + + + align:start position:0% +in the 19th century right but let's +start it with the anti computers at the + + align:start position:0% +start it with the anti computers at the + + + align:start position:0% +start it with the anti computers at the +end of lowered to 1945-46 right slow + + align:start position:0% +end of lowered to 1945-46 right slow + + + align:start position:0% +end of lowered to 1945-46 right slow +scale-up then you hit the 1990s and then + + align:start position:0% +scale-up then you hit the 1990s and then + + + align:start position:0% +scale-up then you hit the 1990s and then +you have very rapid scale up right and + + align:start position:0% +you have very rapid scale up right and + + + align:start position:0% +you have very rapid scale up right and +you've probably had some sense for what + + align:start position:0% +you've probably had some sense for what + + + align:start position:0% +you've probably had some sense for what +that era was like but it was a period of + + align:start position:0% +that era was like but it was a period of + + + align:start position:0% +that era was like but it was a period of +remarkably big growth rise big increase + + align:start position:0% +remarkably big growth rise big increase + + + align:start position:0% +remarkably big growth rise big increase +in GDP growth rate accompanied and + + align:start position:0% +in GDP growth rate accompanied and + + + align:start position:0% +in GDP growth rate accompanied and +driven by a big gain in productivity + + align:start position:0% +driven by a big gain in productivity + + + align:start position:0% +driven by a big gain in productivity +we'll come back to that term in a bit + + align:start position:0% +we'll come back to that term in a bit + + + align:start position:0% +we'll come back to that term in a bit +too + + align:start position:0% +too + + + align:start position:0% +too +then there's always a bubble right so if + + align:start position:0% +then there's always a bubble right so if + + + align:start position:0% +then there's always a bubble right so if +you all are investing in innovation + + align:start position:0% +you all are investing in innovation + + + align:start position:0% +you all are investing in innovation +waves right if you go into the financial + + align:start position:0% +waves right if you go into the financial + + + align:start position:0% +waves right if you go into the financial +sector and you're investing in + + align:start position:0% +sector and you're investing in + + + align:start position:0% +sector and you're investing in +innovation ways trying to ride them you + + align:start position:0% +innovation ways trying to ride them you + + + align:start position:0% +innovation ways trying to ride them you +want to start about here ride it all the + + align:start position:0% +want to start about here ride it all the + + + align:start position:0% +want to start about here ride it all the +way up but never forget that there's + + align:start position:0% +way up but never forget that there's + + + align:start position:0% +way up but never forget that there's +going to be a bubble there is always a + + align:start position:0% +going to be a bubble there is always a + + + align:start position:0% +going to be a bubble there is always a +bubble in every innovation wave so far + + align:start position:0% +bubble in every innovation wave so far + + + align:start position:0% +bubble in every innovation wave so far +there's always been a bubble so in the + + align:start position:0% +there's always been a bubble so in the + + + align:start position:0% +there's always been a bubble so in the +IT revolution that was the dot-com bust + + align:start position:0% +IT revolution that was the dot-com bust + + + align:start position:0% +IT revolution that was the dot-com bust +of 2001 right and then we're in a long + + align:start position:0% +of 2001 right and then we're in a long + + + align:start position:0% +of 2001 right and then we're in a long +period of continued technological + + align:start position:0% +period of continued technological + + + align:start position:0% +period of continued technological +advance but not at the rate of the 1990s + + align:start position:0% +advance but not at the rate of the 1990s + + + align:start position:0% +advance but not at the rate of the 1990s +growth period right and you can think + + align:start position:0% +growth period right and you can think + + + align:start position:0% +growth period right and you can think +about different generations of companies + + align:start position:0% +about different generations of companies + + + align:start position:0% +about different generations of companies +that come along and play different roles + + align:start position:0% +that come along and play different roles + + + align:start position:0% +that come along and play different roles +here and then it's some day and IT may + + align:start position:0% +here and then it's some day and IT may + + + align:start position:0% +here and then it's some day and IT may +be different but some day will reach a + + align:start position:0% +be different but some day will reach a + + + align:start position:0% +be different but some day will reach a +certain amount of technological maturity + + align:start position:0% +certain amount of technological maturity + + + align:start position:0% +certain amount of technological maturity +and the growth rate will stabilize and + + align:start position:0% +and the growth rate will stabilize and + + + align:start position:0% +and the growth rate will stabilize and +then we'll do something else right so + + align:start position:0% +then we'll do something else right so + + + align:start position:0% +then we'll do something else right so +that's kind of what a wave looks like + + align:start position:0% +that's kind of what a wave looks like + + + align:start position:0% +that's kind of what a wave looks like +and again you build into your economy a + + align:start position:0% +and again you build into your economy a + + + align:start position:0% +and again you build into your economy a +series of mesas or plateaus which don't + + align:start position:0% +series of mesas or plateaus which don't + + + align:start position:0% +series of mesas or plateaus which don't +disappear you just go on to the next + + align:start position:0% +disappear you just go on to the next + + + align:start position:0% +disappear you just go on to the next +innovation way this is the way economies + + align:start position:0% +innovation way this is the way economies + + + align:start position:0% +innovation way this is the way economies +grow right through these innovation + + align:start position:0% +grow right through these innovation + + + align:start position:0% +grow right through these innovation +waves so it's a pretty important concept + + align:start position:0% +waves so it's a pretty important concept + + + align:start position:0% +waves so it's a pretty important concept +and if you can get your technology + + align:start position:0% +and if you can get your technology + + + align:start position:0% +and if you can get your technology +advanced into an innovation wave then it + + align:start position:0% +advanced into an innovation wave then it + + + align:start position:0% +advanced into an innovation wave then it +kind of goes on autopilot right and all + + align:start position:0% +kind of goes on autopilot right and all + + + align:start position:0% +kind of goes on autopilot right and all +these things start to occur so that's + + align:start position:0% +these things start to occur so that's + + + align:start position:0% +these things start to occur so that's +where desperately trying to do for + + align:start position:0% +where desperately trying to do for + + + align:start position:0% +where desperately trying to do for +energy we're trying to get it scaled up + + align:start position:0% +energy we're trying to get it scaled up + + + align:start position:0% +energy we're trying to get it scaled up +enough so that it can take off go on + + align:start position:0% +enough so that it can take off go on + + + align:start position:0% +enough so that it can take off go on +autopilot and just kind of happen yeah + + align:start position:0% +autopilot and just kind of happen yeah + + + align:start position:0% +autopilot and just kind of happen yeah +it wipes out lots of the dot-com + + align:start position:0% +it wipes out lots of the dot-com + + + align:start position:0% +it wipes out lots of the dot-com +startups right they die right and only + + align:start position:0% +startups right they die right and only + + + align:start position:0% +startups right they die right and only +the stronger companies with more solid + + align:start position:0% +the stronger companies with more solid + + + align:start position:0% +the stronger companies with more solid +and during models survive right so + + align:start position:0% +and during models survive right so + + + align:start position:0% +and during models survive right so +always anticipate the bubble and get out + + align:start position:0% +always anticipate the bubble and get out + + + align:start position:0% +always anticipate the bubble and get out +in time that's the key + + align:start position:0% + + + + align:start position:0% + +these have a different perspective they + + align:start position:0% +these have a different perspective they + + + align:start position:0% +these have a different perspective they +seen as two bucks they see as one baby + + align:start position:0% +seen as two bucks they see as one baby + + + align:start position:0% +seen as two bucks they see as one baby +bump so for the 90s it was like it cost + + align:start position:0% +bump so for the 90s it was like it cost + + + align:start position:0% +bump so for the 90s it was like it cost +you like $70,000 to buy servers so like + + align:start position:0% +you like $70,000 to buy servers so like + + + align:start position:0% +you like $70,000 to buy servers so like +a lot of capital start and so people get + + align:start position:0% +a lot of capital start and so people get + + + align:start position:0% +a lot of capital start and so people get +really really excited and then they + + align:start position:0% +really really excited and then they + + + align:start position:0% +really really excited and then they +people keep innovating right and you can + + align:start position:0% +people keep innovating right and you can + + + align:start position:0% +people keep innovating right and you can +look at this as a couple of months but + + align:start position:0% +look at this as a couple of months but + + + align:start position:0% +look at this as a couple of months but +not quite in the way Martine that you're + + align:start position:0% +not quite in the way Martine that you're + + + align:start position:0% +not quite in the way Martine that you're +describing but you could look at this + + align:start position:0% +describing but you could look at this + + + align:start position:0% +describing but you could look at this +rise and then this phase that's kind of + + align:start position:0% +rise and then this phase that's kind of + + + align:start position:0% +rise and then this phase that's kind of +two different pieces too so that's + + align:start position:0% +two different pieces too so that's + + + align:start position:0% +two different pieces too so that's +another way of looking at this rapid + + align:start position:0% +another way of looking at this rapid + + + align:start position:0% +another way of looking at this rapid +growth more stable growth with different + + align:start position:0% +growth more stable growth with different + + + align:start position:0% +growth more stable growth with different +firms typically involved in the two + + align:start position:0% +firms typically involved in the two + + + align:start position:0% +firms typically involved in the two +we're gonna do we're gonna dig into this + + align:start position:0% +we're gonna do we're gonna dig into this + + + align:start position:0% +we're gonna do we're gonna dig into this +right so but go ahead you're getting + + align:start position:0% +right so but go ahead you're getting + + + align:start position:0% +right so but go ahead you're getting +rich right a lot of people are getting + + align:start position:0% +rich right a lot of people are getting + + + align:start position:0% +rich right a lot of people are getting +rich right that's the key indicator in + + align:start position:0% +rich right that's the key indicator in + + + align:start position:0% +rich right that's the key indicator in +the IT revolution everybody got a lot + + align:start position:0% +the IT revolution everybody got a lot + + + align:start position:0% +the IT revolution everybody got a lot +better off so all quintiles of the + + align:start position:0% +better off so all quintiles of the + + + align:start position:0% +better off so all quintiles of the +society ended up with a significant game + + align:start position:0% +society ended up with a significant game + + + align:start position:0% +society ended up with a significant game +you know the upper-middle class as usual + + align:start position:0% +you know the upper-middle class as usual + + + align:start position:0% +you know the upper-middle class as usual +gets the biggest game but everybody went + + align:start position:0% +gets the biggest game but everybody went + + + align:start position:0% +gets the biggest game but everybody went +up in that time period + + align:start position:0% + + + + align:start position:0% + +I'm stealing mail and thunder from later + + align:start position:0% +I'm stealing mail and thunder from later + + + align:start position:0% +I'm stealing mail and thunder from later +in the class but I actually will deal + + align:start position:0% +in the class but I actually will deal + + + align:start position:0% +in the class but I actually will deal +with some of this when we talk about + + align:start position:0% +with some of this when we talk about + + + align:start position:0% +with some of this when we talk about +Jorgenson we'll get into productivity + + align:start position:0% +Jorgenson we'll get into productivity + + + align:start position:0% +Jorgenson we'll get into productivity +and GDP growth so make me come back to + + align:start position:0% +and GDP growth so make me come back to + + + align:start position:0% +and GDP growth so make me come back to +this all right so we got through + + align:start position:0% +this all right so we got through + + + align:start position:0% +this all right so we got through +innovation weighs more or less with more + + align:start position:0% +innovation weighs more or less with more + + + align:start position:0% +innovation weighs more or less with more +to come and then we talked earlier about + + align:start position:0% +to come and then we talked earlier about + + + align:start position:0% +to come and then we talked earlier about +this valley of death concept right the + + align:start position:0% +this valley of death concept right the + + + align:start position:0% +this valley of death concept right the +gap between research and later stage + + align:start position:0% +gap between research and later stage + + + align:start position:0% +gap between research and later stage +development that has been the main focus + + align:start position:0% +development that has been the main focus + + + align:start position:0% +development that has been the main focus +of public policy in the innovation field + + align:start position:0% +of public policy in the innovation field + + + align:start position:0% +of public policy in the innovation field +one of the things about this class is + + align:start position:0% +one of the things about this class is + + + align:start position:0% +one of the things about this class is +that you're gonna realize this is only + + align:start position:0% +that you're gonna realize this is only + + + align:start position:0% +that you're gonna realize this is only +one part of a much more complicated in + + align:start position:0% +one part of a much more complicated in + + + align:start position:0% +one part of a much more complicated in +Richards stories so we're gonna be + + align:start position:0% +Richards stories so we're gonna be + + + align:start position:0% +Richards stories so we're gonna be +telling a lot of stories in addition to + + align:start position:0% +telling a lot of stories in addition to + + + align:start position:0% +telling a lot of stories in addition to +this story but that's one of the stories + + align:start position:0% +this story but that's one of the stories + + + align:start position:0% +this story but that's one of the stories +we're gonna tell + + align:start position:0% +we're gonna tell + + + align:start position:0% +we're gonna tell +so any further questions about this I + + align:start position:0% + + + + align:start position:0% + +just wanted to get some basic vocabulary + + align:start position:0% +just wanted to get some basic vocabulary + + + align:start position:0% +just wanted to get some basic vocabulary +kind of out on the table let me say a + + align:start position:0% +kind of out on the table let me say a + + + align:start position:0% +kind of out on the table let me say a +few more introductory things the + + align:start position:0% +few more introductory things the + + + align:start position:0% +few more introductory things the +relationship between science and + + align:start position:0% +relationship between science and + + + align:start position:0% +relationship between science and +technology really before the mid 19th + + align:start position:0% +technology really before the mid 19th + + + align:start position:0% +technology really before the mid 19th +century technology was wasn't really + + align:start position:0% +century technology was wasn't really + + + align:start position:0% +century technology was wasn't really +based on science it was based in a way + + align:start position:0% +based on science it was based in a way + + + align:start position:0% +based on science it was based in a way +on tinkering and that's not to say that + + align:start position:0% +on tinkering and that's not to say that + + + align:start position:0% +on tinkering and that's not to say that +science didn't enter at some critical + + align:start position:0% +science didn't enter at some critical + + + align:start position:0% +science didn't enter at some critical +stages it does but the initial invention + + align:start position:0% +stages it does but the initial invention + + + align:start position:0% +stages it does but the initial invention +moments our technology types fiddling + + align:start position:0% +moments our technology types fiddling + + + align:start position:0% +moments our technology types fiddling +around in the 19th century in late 18th + + align:start position:0% +around in the 19th century in late 18th + + + align:start position:0% +around in the 19th century in late 18th +century equivalent of a garage right so + + align:start position:0% +century equivalent of a garage right so + + + align:start position:0% +century equivalent of a garage right so +science is not far enough along to be + + align:start position:0% +science is not far enough along to be + + + align:start position:0% +science is not far enough along to be +able to give birth to technology for at + + align:start position:0% +able to give birth to technology for at + + + align:start position:0% +able to give birth to technology for at +least a large part of the 19th century + + align:start position:0% +least a large part of the 19th century + + + align:start position:0% +least a large part of the 19th century +but now we're in an era where basic + + align:start position:0% +but now we're in an era where basic + + + align:start position:0% +but now we're in an era where basic +science definitely can give rise to + + align:start position:0% +science definitely can give rise to + + + align:start position:0% +science definitely can give rise to +technology now somebody a friend I know + + align:start position:0% +technology now somebody a friend I know + + + align:start position:0% +technology now somebody a friend I know +pretty well named Lee Buchanan it was a + + align:start position:0% +pretty well named Lee Buchanan it was a + + + align:start position:0% +pretty well named Lee Buchanan it was a +former deputy director of DARPA would + + align:start position:0% +former deputy director of DARPA would + + + align:start position:0% +former deputy director of DARPA would +always insist that yeah that's all fine + + align:start position:0% +always insist that yeah that's all fine + + + align:start position:0% +always insist that yeah that's all fine +but I'm running DARPA and I get nothing + + align:start position:0% +but I'm running DARPA and I get nothing + + + align:start position:0% +but I'm running DARPA and I get nothing +out of basic science I could drop all + + align:start position:0% +out of basic science I could drop all + + + align:start position:0% +out of basic science I could drop all +that funding I never miss it he + + align:start position:0% +that funding I never miss it he + + + align:start position:0% +that funding I never miss it he +explained to me one day so you know I + + align:start position:0% +explained to me one day so you know I + + + align:start position:0% +explained to me one day so you know I +think he's wrong but you should know + + align:start position:0% +think he's wrong but you should know + + + align:start position:0% +think he's wrong but you should know +there's a debate about this including in + + align:start position:0% +there's a debate about this including in + + + align:start position:0% +there's a debate about this including in +our most famous advanced technology + + align:start position:0% +our most famous advanced technology + + + align:start position:0% +our most famous advanced technology +agency but I think in the end the + + align:start position:0% +agency but I think in the end the + + + align:start position:0% +agency but I think in the end the +evidence is strong that science can now + + align:start position:0% +evidence is strong that science can now + + + align:start position:0% +evidence is strong that science can now +give rise to technology but keep in mind + + align:start position:0% +give rise to technology but keep in mind + + + align:start position:0% +give rise to technology but keep in mind +that technology still gives rise to + + align:start position:0% +that technology still gives rise to + + + align:start position:0% +that technology still gives rise to +science and we'll talk about what that + + align:start position:0% +science and we'll talk about what that + + + align:start position:0% +science and we'll talk about what that +means in a bit now here's our first MIT + + align:start position:0% +means in a bit now here's our first MIT + + + align:start position:0% +means in a bit now here's our first MIT +great forgive the MIT centric focus here + + align:start position:0% +great forgive the MIT centric focus here + + + align:start position:0% +great forgive the MIT centric focus here +for our colleagues from other + + align:start position:0% +for our colleagues from other + + + align:start position:0% +for our colleagues from other +institutions you'll have to bear with me + + align:start position:0% +institutions you'll have to bear with me + + + align:start position:0% +institutions you'll have to bear with me +Robert Solow won the Nobel Prize in + + align:start position:0% +Robert Solow won the Nobel Prize in + + + align:start position:0% +Robert Solow won the Nobel Prize in +Economics in 1980 + + align:start position:0% +Economics in 1980 + + + align:start position:0% +Economics in 1980 +for essentially developing growth + + align:start position:0% +for essentially developing growth + + + align:start position:0% +for essentially developing growth +economics I mean he created an entire + + align:start position:0% +economics I mean he created an entire + + + align:start position:0% +economics I mean he created an entire +field of economics and he's a just a + + align:start position:0% +field of economics and he's a just a + + + align:start position:0% +field of economics and he's a just a +wonderful human being he's still around + + align:start position:0% +wonderful human being he's still around + + + align:start position:0% +wonderful human being he's still around +if you ever get a chance to meet him or + + align:start position:0% +if you ever get a chance to meet him or + + + align:start position:0% +if you ever get a chance to meet him or +listen to him don't miss it it's one of + + align:start position:0% +listen to him don't miss it it's one of + + + align:start position:0% +listen to him don't miss it it's one of +the greats + + align:start position:0% +the greats + + + align:start position:0% +the greats +forget the Nobel Prize the really + + align:start position:0% +forget the Nobel Prize the really + + + align:start position:0% +forget the Nobel Prize the really +important prize is the President's Medal + + align:start position:0% +important prize is the President's Medal + + + align:start position:0% +important prize is the President's Medal +of Technology right + + align:start position:0% +of Technology right + + + align:start position:0% +of Technology right +the only economist who's ever won the + + align:start position:0% +the only economist who's ever won the + + + align:start position:0% +the only economist who's ever won the +President's Medal of Technology there is + + align:start position:0% +President's Medal of Technology there is + + + align:start position:0% +President's Medal of Technology there is +getting it from Clinton it's really + + align:start position:0% +getting it from Clinton it's really + + + align:start position:0% +getting it from Clinton it's really +unusual his work is so important in its + + align:start position:0% +unusual his work is so important in its + + + align:start position:0% +unusual his work is so important in its +implications for technology development + + align:start position:0% +implications for technology development + + + align:start position:0% +implications for technology development +that he gets the technology prize too + + align:start position:0% +that he gets the technology prize too + + + align:start position:0% +that he gets the technology prize too +from the president I can't tell you what + + align:start position:0% +from the president I can't tell you what + + + align:start position:0% +from the president I can't tell you what +a nice person he is + + align:start position:0% +a nice person he is + + + align:start position:0% +a nice person he is +I once watched him testify in front of + + align:start position:0% +I once watched him testify in front of + + + align:start position:0% +I once watched him testify in front of +the House Science Committee and you know + + align:start position:0% +the House Science Committee and you know + + + align:start position:0% +the House Science Committee and you know +it was like you know God has entered the + + align:start position:0% +it was like you know God has entered the + + + align:start position:0% +it was like you know God has entered the +room solos come into the room + + align:start position:0% +room solos come into the room + + + align:start position:0% +room solos come into the room +and the committee all knew that + + align:start position:0% +and the committee all knew that + + + align:start position:0% +and the committee all knew that +innovation base growth theory comes from + + align:start position:0% +innovation base growth theory comes from + + + align:start position:0% +innovation base growth theory comes from +this guy and you know they were just + + align:start position:0% +this guy and you know they were just + + + align:start position:0% +this guy and you know they were just +incredibly complimentary and the + + align:start position:0% + + + + align:start position:0% + +congressman who was like the number two + + align:start position:0% +congressman who was like the number two + + + align:start position:0% +congressman who was like the number two +or three and the committee server + + align:start position:0% +or three and the committee server + + + align:start position:0% +or three and the committee server +question he was fairly early and she + + align:start position:0% +question he was fairly early and she + + + align:start position:0% +question he was fairly early and she +turned to him and said you know doctor + + align:start position:0% +turned to him and said you know doctor + + + align:start position:0% +turned to him and said you know doctor +you know for the purpose of this hearing + + align:start position:0% +you know for the purpose of this hearing + + + align:start position:0% +you know for the purpose of this hearing +you know what what what should we call + + align:start position:0% +you know what what what should we call + + + align:start position:0% +you know what what what should we call +you noblest you know what terms should + + align:start position:0% +you noblest you know what terms should + + + align:start position:0% +you noblest you know what terms should +we use for you and he kind of leans back + + align:start position:0% +we use for you and he kind of leans back + + + align:start position:0% +we use for you and he kind of leans back +and he says well you know I was a tech + + align:start position:0% +and he says well you know I was a tech + + + align:start position:0% +and he says well you know I was a tech +sergeant in the army + + align:start position:0% +sergeant in the army + + + align:start position:0% +sergeant in the army +and during the Korean War and I really + + align:start position:0% +and during the Korean War and I really + + + align:start position:0% +and during the Korean War and I really +came to like the title Sarge so maybe he + + align:start position:0% +came to like the title Sarge so maybe he + + + align:start position:0% +came to like the title Sarge so maybe he +could call me Sarge and there's this you + + align:start position:0% +could call me Sarge and there's this you + + + align:start position:0% +could call me Sarge and there's this you +know fancy congressional you know + + align:start position:0% +know fancy congressional you know + + + align:start position:0% +know fancy congressional you know +committee calling Robert Solow Sarge for + + align:start position:0% +committee calling Robert Solow Sarge for + + + align:start position:0% +committee calling Robert Solow Sarge for +the rest of the hearing was absolutely + + align:start position:0% +the rest of the hearing was absolutely + + + align:start position:0% +the rest of the hearing was absolutely +just they he had them eating out of his + + align:start position:0% +just they he had them eating out of his + + + align:start position:0% +just they he had them eating out of his +hands he was just funny and charming and + + align:start position:0% +hands he was just funny and charming and + + + align:start position:0% +hands he was just funny and charming and +incredibly thoughtful all at the same + + align:start position:0% +incredibly thoughtful all at the same + + + align:start position:0% +incredibly thoughtful all at the same +time so he's quite an amazing figure + + align:start position:0% + + + + align:start position:0% + +he wins the Nobel Prize for essentially + + align:start position:0% +he wins the Nobel Prize for essentially + + + align:start position:0% +he wins the Nobel Prize for essentially +blowing up a large part of classical + + align:start position:0% +blowing up a large part of classical + + + align:start position:0% +blowing up a large part of classical +economics and the problem with classical + + align:start position:0% +economics and the problem with classical + + + align:start position:0% +economics and the problem with classical +economics and look I asked you to read + + align:start position:0% +economics and look I asked you to read + + + align:start position:0% +economics and look I asked you to read +this and it's his Nobel Prize talks so + + align:start position:0% +this and it's his Nobel Prize talks so + + + align:start position:0% +this and it's his Nobel Prize talks so +it's for economics writing it's fairly + + align:start position:0% +it's for economics writing it's fairly + + + align:start position:0% +it's for economics writing it's fairly +accessible but even then it's not simple + + align:start position:0% +accessible but even then it's not simple + + + align:start position:0% +accessible but even then it's not simple +when if you all haven't if you're going + + align:start position:0% +when if you all haven't if you're going + + + align:start position:0% +when if you all haven't if you're going +to be reading it and I'm gonna ask + + align:start position:0% +to be reading it and I'm gonna ask + + + align:start position:0% +to be reading it and I'm gonna ask +everybody who hasn't done the readings + + align:start position:0% +everybody who hasn't done the readings + + + align:start position:0% +everybody who hasn't done the readings +yet for this class because I know it's + + align:start position:0% +yet for this class because I know it's + + + align:start position:0% +yet for this class because I know it's +your first time with access to the + + align:start position:0% +your first time with access to the + + + align:start position:0% +your first time with access to the +stellar site but just blow by the + + align:start position:0% +stellar site but just blow by the + + + align:start position:0% +stellar site but just blow by the +economics formulation period just blow + + align:start position:0% +economics formulation period just blow + + + align:start position:0% +economics formulation period just blow +by the econometrics just get the basic + + align:start position:0% +by the econometrics just get the basic + + + align:start position:0% +by the econometrics just get the basic +ideas down for both solo and for Romer + + align:start position:0% +ideas down for both solo and for Romer + + + align:start position:0% +ideas down for both solo and for Romer +particular Romer when it's a + + align:start position:0% +particular Romer when it's a + + + align:start position:0% +particular Romer when it's a +particularly complicated reading for + + align:start position:0% +particularly complicated reading for + + + align:start position:0% +particularly complicated reading for +those of you who have not studied + + align:start position:0% +those of you who have not studied + + + align:start position:0% +those of you who have not studied +economics but he goes after classical + + align:start position:0% +economics but he goes after classical + + + align:start position:0% +economics but he goes after classical +economic theory and just to summarize in + + align:start position:0% +economic theory and just to summarize in + + + align:start position:0% +economic theory and just to summarize in +a simpler way than is really fair to + + align:start position:0% +a simpler way than is really fair to + + + align:start position:0% +a simpler way than is really fair to +classical economics classical economics + + align:start position:0% +classical economics classical economics + + + align:start position:0% +classical economics classical economics +asked when an economy is capable of + + align:start position:0% +asked when an economy is capable of + + + align:start position:0% +asked when an economy is capable of +steady economic growth and they never + + align:start position:0% +steady economic growth and they never + + + align:start position:0% +steady economic growth and they never +came up with a good answer they the + + align:start position:0% +came up with a good answer they the + + + align:start position:0% +came up with a good answer they the +formulation was when the national + + align:start position:0% +formulation was when the national + + + align:start position:0% +formulation was when the national +savings rate which means income saved in + + align:start position:0% +savings rate which means income saved in + + + align:start position:0% +savings rate which means income saved in +the economy equals the capital supply + + align:start position:0% +the economy equals the capital supply + + + align:start position:0% +the economy equals the capital supply +capital output ratio and the rate of + + align:start position:0% +capital output ratio and the rate of + + + align:start position:0% +capital output ratio and the rate of +labor force growth that's labor supply + + align:start position:0% +labor force growth that's labor supply + + + align:start position:0% +labor force growth that's labor supply +right then you get growth that was the + + align:start position:0% +right then you get growth that was the + + + align:start position:0% +right then you get growth that was the +theory right so let me simplify that + + align:start position:0% +theory right so let me simplify that + + + align:start position:0% +theory right so let me simplify that +even more + + align:start position:0% +even more + + + align:start position:0% +even more +essentially they've got two factors + + align:start position:0% +essentially they've got two factors + + + align:start position:0% +essentially they've got two factors +Capital supply and labor supply and it's + + align:start position:0% +Capital supply and labor supply and it's + + + align:start position:0% +Capital supply and labor supply and it's +not capitalist and part like all the + + align:start position:0% +not capitalist and part like all the + + + align:start position:0% +not capitalist and part like all the +money it's capitalist like plant + + align:start position:0% +money it's capitalist like plant + + + align:start position:0% +money it's capitalist like plant +equipment as well as resources that's + + align:start position:0% +equipment as well as resources that's + + + align:start position:0% +equipment as well as resources that's +available and labor supply includes not + + align:start position:0% +available and labor supply includes not + + + align:start position:0% +available and labor supply includes not +just you know the number of workers but + + align:start position:0% +just you know the number of workers but + + + align:start position:0% +just you know the number of workers but +education health systems and the + + align:start position:0% +education health systems and the + + + align:start position:0% +education health systems and the +supporting systems for that too so it's + + align:start position:0% +supporting systems for that too so it's + + + align:start position:0% +supporting systems for that too so it's +these are bigger concepts so essentially + + align:start position:0% +these are bigger concepts so essentially + + + align:start position:0% +these are bigger concepts so essentially +their theory was that these are the + + align:start position:0% +their theory was that these are the + + + align:start position:0% +their theory was that these are the +contributing factors capital supply and + + align:start position:0% +contributing factors capital supply and + + + align:start position:0% +contributing factors capital supply and +labor supply and when you get those in + + align:start position:0% +labor supply and when you get those in + + + align:start position:0% +labor supply and when you get those in +the right balance supported by your + + align:start position:0% +the right balance supported by your + + + align:start position:0% +the right balance supported by your +national saving rate which is + + align:start position:0% +national saving rate which is + + + align:start position:0% +national saving rate which is +essentially + + align:start position:0% +essentially + + + align:start position:0% +essentially +the funder of those systems then you + + align:start position:0% +the funder of those systems then you + + + align:start position:0% +the funder of those systems then you +will get economic growth it's a static + + align:start position:0% +will get economic growth it's a static + + + align:start position:0% +will get economic growth it's a static +view okay it's an equilibrium system and + + align:start position:0% +view okay it's an equilibrium system and + + + align:start position:0% +view okay it's an equilibrium system and +these factors have to be in the right + + align:start position:0% +these factors have to be in the right + + + align:start position:0% +these factors have to be in the right +balance they constantly tend to throw + + align:start position:0% +balance they constantly tend to throw + + + align:start position:0% +balance they constantly tend to throw +each other off for growth to occur so + + align:start position:0% +each other off for growth to occur so + + + align:start position:0% +each other off for growth to occur so +you explain a business cycle from this I + + align:start position:0% +you explain a business cycle from this I + + + align:start position:0% +you explain a business cycle from this I +mean not really but that's what it + + align:start position:0% +mean not really but that's what it + + + align:start position:0% +mean not really but that's what it +attempts to do and capitalism becomes + + align:start position:0% +attempts to do and capitalism becomes + + + align:start position:0% +attempts to do and capitalism becomes +just periods of alternating you know + + align:start position:0% +just periods of alternating you know + + + align:start position:0% +just periods of alternating you know +improvement and gain and decline right + + align:start position:0% +improvement and gain and decline right + + + align:start position:0% +improvement and gain and decline right +so it's a business cycle kind of + + align:start position:0% +so it's a business cycle kind of + + + align:start position:0% +so it's a business cycle kind of +explanation we're seeing unemployment + + align:start position:0% +explanation we're seeing unemployment + + + align:start position:0% +explanation we're seeing unemployment +and then labor shortages right + + align:start position:0% +and then labor shortages right + + + align:start position:0% +and then labor shortages right +everything is throwing each other + + align:start position:0% +everything is throwing each other + + + align:start position:0% +everything is throwing each other +overtime out of balance it is not a + + align:start position:0% +overtime out of balance it is not a + + + align:start position:0% +overtime out of balance it is not a +dynamic model I should explain that + + align:start position:0% +dynamic model I should explain that + + + align:start position:0% +dynamic model I should explain that +classical economics you know it + + align:start position:0% +classical economics you know it + + + align:start position:0% +classical economics you know it +basically starts with Adam Smith and + + align:start position:0% +basically starts with Adam Smith and + + + align:start position:0% +basically starts with Adam Smith and +lasts until really the post-war - period + + align:start position:0% +lasts until really the post-war - period + + + align:start position:0% +lasts until really the post-war - period +and the problem with economics that was + + align:start position:0% +and the problem with economics that was + + + align:start position:0% +and the problem with economics that was +so frustrating to economists as well as + + align:start position:0% +so frustrating to economists as well as + + + align:start position:0% +so frustrating to economists as well as +policymakers was that it wasn't it + + align:start position:0% +policymakers was that it wasn't it + + + align:start position:0% +policymakers was that it wasn't it +didn't really have a foundational set of + + align:start position:0% +didn't really have a foundational set of + + + align:start position:0% +didn't really have a foundational set of +operating and working assumptions that + + align:start position:0% +operating and working assumptions that + + + align:start position:0% +operating and working assumptions that +were reliable it didn't have a reliable + + align:start position:0% +were reliable it didn't have a reliable + + + align:start position:0% +were reliable it didn't have a reliable +base so if you had you know 15 of you + + align:start position:0% +base so if you had you know 15 of you + + + align:start position:0% +base so if you had you know 15 of you +were economists sitting around trying to + + align:start position:0% +were economists sitting around trying to + + + align:start position:0% +were economists sitting around trying to +explain to me a policymaker + + align:start position:0% +explain to me a policymaker + + + align:start position:0% +explain to me a policymaker +how come there was a Great Depression + + align:start position:0% +how come there was a Great Depression + + + align:start position:0% +how come there was a Great Depression +you would have at least thirty ideas on + + align:start position:0% +you would have at least thirty ideas on + + + align:start position:0% +you would have at least thirty ideas on +the table right it wasn't really + + align:start position:0% +the table right it wasn't really + + + align:start position:0% +the table right it wasn't really +terribly helpful to me right there were + + align:start position:0% +terribly helpful to me right there were + + + align:start position:0% +terribly helpful to me right there were +just too many variables so social + + align:start position:0% +just too many variables so social + + + align:start position:0% +just too many variables so social +science in the course of war - saw what + + align:start position:0% +science in the course of war - saw what + + + align:start position:0% +science in the course of war - saw what +physics did right I'm staring in our to + + align:start position:0% +physics did right I'm staring in our to + + + align:start position:0% +physics did right I'm staring in our to +physics guys here oh there's more + + align:start position:0% +physics guys here oh there's more + + + align:start position:0% +physics guys here oh there's more +several physics those physics in that + + align:start position:0% +several physics those physics in that + + + align:start position:0% +several physics those physics in that +pre-warp one or two period attempts to + + align:start position:0% +pre-warp one or two period attempts to + + + align:start position:0% +pre-warp one or two period attempts to +get down to basic known scientifically + + align:start position:0% +get down to basic known scientifically + + + align:start position:0% +get down to basic known scientifically +established you know currents + + align:start position:0% +established you know currents + + + align:start position:0% +established you know currents +of fact that can be demonstrated and + + align:start position:0% +of fact that can be demonstrated and + + + align:start position:0% +of fact that can be demonstrated and +known so that's the whole particle + + align:start position:0% +known so that's the whole particle + + + align:start position:0% +known so that's the whole particle +physics endeavor right we're gonna weed + + align:start position:0% +physics endeavor right we're gonna weed + + + align:start position:0% +physics endeavor right we're gonna weed +out extraneous stuff get down to a + + align:start position:0% +out extraneous stuff get down to a + + + align:start position:0% +out extraneous stuff get down to a +fairly small subset of stuff that we + + align:start position:0% +fairly small subset of stuff that we + + + align:start position:0% +fairly small subset of stuff that we +really know and then work with those is + + align:start position:0% +really know and then work with those is + + + align:start position:0% +really know and then work with those is +building blocks so all of the social + + align:start position:0% +building blocks so all of the social + + + align:start position:0% +building blocks so all of the social +sciences watch what happens to physics + + align:start position:0% +sciences watch what happens to physics + + + align:start position:0% +sciences watch what happens to physics +in that pre-world War two period and + + align:start position:0% +in that pre-world War two period and + + + align:start position:0% +in that pre-world War two period and +that World War two period we're + + align:start position:0% +that World War two period we're + + + align:start position:0% +that World War two period we're +eventually things like nuclear weapons + + align:start position:0% +eventually things like nuclear weapons + + + align:start position:0% +eventually things like nuclear weapons +and power come about and they think gee + + align:start position:0% +and power come about and they think gee + + + align:start position:0% +and power come about and they think gee +maybe they're onto something maybe + + align:start position:0% +maybe they're onto something maybe + + + align:start position:0% +maybe they're onto something maybe +that's a practice that we ought to do + + align:start position:0% +that's a practice that we ought to do + + + align:start position:0% +that's a practice that we ought to do +can we get down to a relatively small + + align:start position:0% +can we get down to a relatively small + + + align:start position:0% +can we get down to a relatively small +number of known variables and in effect + + align:start position:0% +number of known variables and in effect + + + align:start position:0% +number of known variables and in effect +create a known system here that's much + + align:start position:0% +create a known system here that's much + + + align:start position:0% +create a known system here that's much +more reliable than the kind of pre-war + + align:start position:0% +more reliable than the kind of pre-war + + + align:start position:0% +more reliable than the kind of pre-war +to guesswork in economics that everybody + + align:start position:0% +to guesswork in economics that everybody + + + align:start position:0% +to guesswork in economics that everybody +would be working from a similar kind of + + align:start position:0% +would be working from a similar kind of + + + align:start position:0% +would be working from a similar kind of +problem set so that's the enterprise + + align:start position:0% +problem set so that's the enterprise + + + align:start position:0% +problem set so that's the enterprise +solo is a neoclassical economist so he's + + align:start position:0% +solo is a neoclassical economist so he's + + + align:start position:0% +solo is a neoclassical economist so he's +post classical economics he's Troy which + + align:start position:0% +post classical economics he's Troy which + + + align:start position:0% +post classical economics he's Troy which +Paul Samuelson here is you know one of + + align:start position:0% +Paul Samuelson here is you know one of + + + align:start position:0% +Paul Samuelson here is you know one of +the tiny handful of great leaders of + + align:start position:0% +the tiny handful of great leaders of + + + align:start position:0% +the tiny handful of great leaders of +that tries to get economics down to a + + align:start position:0% +that tries to get economics down to a + + + align:start position:0% +that tries to get economics down to a +subset of known factors and known + + align:start position:0% +subset of known factors and known + + + align:start position:0% +subset of known factors and known +realities that can be demonstrated + + align:start position:0% +realities that can be demonstrated + + + align:start position:0% +realities that can be demonstrated +mathlab met and mathematically proven so + + align:start position:0% +mathlab met and mathematically proven so + + + align:start position:0% +mathlab met and mathematically proven so +that's what neoclassical economics is up + + align:start position:0% +that's what neoclassical economics is up + + + align:start position:0% +that's what neoclassical economics is up +against that's what they're trying to do + + align:start position:0% +against that's what they're trying to do + + + align:start position:0% +against that's what they're trying to do +solo is a neoclassical economist and he + + align:start position:0% +solo is a neoclassical economist and he + + + align:start position:0% +solo is a neoclassical economist and he +is working through this problem of + + align:start position:0% +is working through this problem of + + + align:start position:0% +is working through this problem of +growth so you know we had what 150 200 + + align:start position:0% +growth so you know we had what 150 200 + + + align:start position:0% +growth so you know we had what 150 200 +years worth of economics and they didn't + + align:start position:0% +years worth of economics and they didn't + + + align:start position:0% +years worth of economics and they didn't +have a viable growth theory I mean + + align:start position:0% +have a viable growth theory I mean + + + align:start position:0% +have a viable growth theory I mean +what's with this right so fortunately + + align:start position:0% +what's with this right so fortunately + + + align:start position:0% +what's with this right so fortunately +solo comes along and he forms one and he + + align:start position:0% +solo comes along and he forms one and he + + + align:start position:0% +solo comes along and he forms one and he +said the story told by these classical + + align:start position:0% +said the story told by these classical + + + align:start position:0% +said the story told by these classical +models felt wrong and he noted that and + + align:start position:0% +models felt wrong and he noted that and + + + align:start position:0% +models felt wrong and he noted that and +one of the classical economists Harry + + align:start position:0% +one of the classical economists Harry + + + align:start position:0% +one of the classical economists Harry +there was a hint of and generalizations + + align:start position:0% +there was a hint of and generalizations + + + align:start position:0% +there was a hint of and generalizations +about not the proneural behavior and he + + align:start position:0% +about not the proneural behavior and he + + + align:start position:0% +about not the proneural behavior and he +decided that he could think about + + align:start position:0% +decided that he could think about + + + align:start position:0% +decided that he could think about +replacing the capital and labour output + + align:start position:0% +replacing the capital and labour output + + + align:start position:0% +replacing the capital and labour output +with a richer and more realistic + + align:start position:0% +with a richer and more realistic + + + align:start position:0% +with a richer and more realistic +representation of technology + + align:start position:0% + + + + align:start position:0% + +which would be a new theory of + + align:start position:0% +which would be a new theory of + + + align:start position:0% +which would be a new theory of +production not just an assessment of + + align:start position:0% +production not just an assessment of + + + align:start position:0% +production not just an assessment of +output levels that's the key thought + + align:start position:0% +output levels that's the key thought + + + align:start position:0% +output levels that's the key thought +pattern here so it's not that capital + + align:start position:0% +pattern here so it's not that capital + + + align:start position:0% +pattern here so it's not that capital +supply and labor supply aren't important + + align:start position:0% +supply and labor supply aren't important + + + align:start position:0% +supply and labor supply aren't important +right they remain important factors but + + align:start position:0% +right they remain important factors but + + + align:start position:0% +right they remain important factors but +they are not close to as important as + + align:start position:0% +they are not close to as important as + + + align:start position:0% +they are not close to as important as +this more realistic representation of + + align:start position:0% +this more realistic representation of + + + align:start position:0% +this more realistic representation of +technology which we also calls as I said + + align:start position:0% +technology which we also calls as I said + + + align:start position:0% +technology which we also calls as I said +earlier technological and related + + align:start position:0% +earlier technological and related + + + align:start position:0% +earlier technological and related +innovation so it's not just the + + align:start position:0% +innovation so it's not just the + + + align:start position:0% +innovation so it's not just the +technology right it includes that bundle + + align:start position:0% +technology right it includes that bundle + + + align:start position:0% +technology right it includes that bundle +of stuff around the technology like + + align:start position:0% +of stuff around the technology like + + + align:start position:0% +of stuff around the technology like +process and business models that enable + + align:start position:0% +process and business models that enable + + + align:start position:0% +process and business models that enable +it okay but in the end it's + + align:start position:0% +it okay but in the end it's + + + align:start position:0% +it okay but in the end it's +technology-based innovation that becomes + + align:start position:0% +technology-based innovation that becomes + + + align:start position:0% +technology-based innovation that becomes +the heart of economic growth and soullow + + align:start position:0% +the heart of economic growth and soullow + + + align:start position:0% +the heart of economic growth and soullow +does a 50-year review of the US economy + + align:start position:0% +does a 50-year review of the US economy + + + align:start position:0% +does a 50-year review of the US economy +and he concludes that in that 50 year + + align:start position:0% +and he concludes that in that 50 year + + + align:start position:0% +and he concludes that in that 50 year +time period technological and related + + align:start position:0% +time period technological and related + + + align:start position:0% +time period technological and related +innovation is the dominant causative + + align:start position:0% +innovation is the dominant causative + + + align:start position:0% +innovation is the dominant causative +factor of US economic growth to the tune + + align:start position:0% +factor of US economic growth to the tune + + + align:start position:0% +factor of US economic growth to the tune +of about two thirds so in that range + + align:start position:0% +of about two thirds so in that range + + + align:start position:0% +of about two thirds so in that range +somewhere between 50% and higher we may + + align:start position:0% +somewhere between 50% and higher we may + + + align:start position:0% +somewhere between 50% and higher we may +be on the higher end of that now in this + + align:start position:0% +be on the higher end of that now in this + + + align:start position:0% +be on the higher end of that now in this +era they were in now and that's his + + align:start position:0% +era they were in now and that's his + + + align:start position:0% +era they were in now and that's his +that's his key breakthrough so capital + + align:start position:0% +that's his key breakthrough so capital + + + align:start position:0% +that's his key breakthrough so capital +supply and labor supply are significant + + align:start position:0% +supply and labor supply are significant + + + align:start position:0% +supply and labor supply are significant +but they're down in the teens now he + + align:start position:0% +but they're down in the teens now he + + + align:start position:0% +but they're down in the teens now he +acknowledges that the rate of growth is + + align:start position:0% +acknowledges that the rate of growth is + + + align:start position:0% +acknowledges that the rate of growth is +going to depend upon the investment rate + + align:start position:0% +going to depend upon the investment rate + + + align:start position:0% +going to depend upon the investment rate +because that'll be effective that help + + align:start position:0% +because that'll be effective that help + + + align:start position:0% +because that'll be effective that help +drives it so capital supplier is still + + align:start position:0% +drives it so capital supplier is still + + + align:start position:0% +drives it so capital supplier is still +significant but old growth theory + + align:start position:0% +significant but old growth theory + + + align:start position:0% +significant but old growth theory +classical growth theory is mechanical it + + align:start position:0% +classical growth theory is mechanical it + + + align:start position:0% +classical growth theory is mechanical it +is an equilibrium system it's constantly + + align:start position:0% +is an equilibrium system it's constantly + + + align:start position:0% +is an equilibrium system it's constantly +going in and out of balance hence those + + align:start position:0% +going in and out of balance hence those + + + align:start position:0% +going in and out of balance hence those +business cycles the great thing about + + align:start position:0% +business cycles the great thing about + + + align:start position:0% +business cycles the great thing about +what solo comes up with is that he + + align:start position:0% +what solo comes up with is that he + + + align:start position:0% +what solo comes up with is that he +brings a dynamic factor into + + align:start position:0% +brings a dynamic factor into + + + align:start position:0% +brings a dynamic factor into +understanding growth + + align:start position:0% + + + + align:start position:0% + +I'll skip some of this this can be very + + align:start position:0% +I'll skip some of this this can be very + + + align:start position:0% +I'll skip some of this this can be very +good news okay so economics goes from + + align:start position:0% +good news okay so economics goes from + + + align:start position:0% +good news okay so economics goes from +like this kind of dark and dismal + + align:start position:0% +like this kind of dark and dismal + + + align:start position:0% +like this kind of dark and dismal +science to a way in which a society can + + align:start position:0% +science to a way in which a society can + + + align:start position:0% +science to a way in which a society can +grow right and increase its well-being + + align:start position:0% +grow right and increase its well-being + + + align:start position:0% +grow right and increase its well-being +by introducing more technological and + + align:start position:0% +by introducing more technological and + + + align:start position:0% +by introducing more technological and +related innovation that's you know + + align:start position:0% +related innovation that's you know + + + align:start position:0% +related innovation that's you know +profoundly good news it gets us out of + + align:start position:0% +profoundly good news it gets us out of + + + align:start position:0% +profoundly good news it gets us out of +this old equilibrium system this old + + align:start position:0% +this old equilibrium system this old + + + align:start position:0% +this old equilibrium system this old +dismal science one two what if you can + + align:start position:0% +dismal science one two what if you can + + + align:start position:0% +dismal science one two what if you can +get it going what can be a dynamic + + align:start position:0% +get it going what can be a dynamic + + + align:start position:0% +get it going what can be a dynamic +pattern and improve societal well-being + + align:start position:0% +pattern and improve societal well-being + + + align:start position:0% +pattern and improve societal well-being +we can see these technological + + align:start position:0% +we can see these technological + + + align:start position:0% +we can see these technological +innovations and the way they change + + align:start position:0% +innovations and the way they change + + + align:start position:0% +innovations and the way they change +society in the past right so we think + + align:start position:0% +society in the past right so we think + + + align:start position:0% +society in the past right so we think +about what the 19th century looks like + + align:start position:0% +about what the 19th century looks like + + + align:start position:0% +about what the 19th century looks like +and I mentioned some of these before but + + align:start position:0% +and I mentioned some of these before but + + + align:start position:0% +and I mentioned some of these before but +you know canals and railroads and + + align:start position:0% +you know canals and railroads and + + + align:start position:0% +you know canals and railroads and +electricity and the Telegraph and the + + align:start position:0% +electricity and the Telegraph and the + + + align:start position:0% +electricity and the Telegraph and the +telephone and more recent times + + align:start position:0% +telephone and more recent times + + + align:start position:0% +telephone and more recent times +aerospace and computing and the Internet + + align:start position:0% +aerospace and computing and the Internet + + + align:start position:0% +aerospace and computing and the Internet +these are all growth transformers right + + align:start position:0% +these are all growth transformers right + + + align:start position:0% +these are all growth transformers right +and you've seen a couple of these you've + + align:start position:0% +and you've seen a couple of these you've + + + align:start position:0% +and you've seen a couple of these you've +seen the IT revolution in your lifetime + + align:start position:0% +seen the IT revolution in your lifetime + + + align:start position:0% +seen the IT revolution in your lifetime +and you've seen a smaller scale but + + align:start position:0% +and you've seen a smaller scale but + + + align:start position:0% +and you've seen a smaller scale but +still significant biotech revolution + + align:start position:0% +still significant biotech revolution + + + align:start position:0% +still significant biotech revolution +right which is still both of what you're + + align:start position:0% +right which is still both of what you're + + + align:start position:0% +right which is still both of what you're +still playing out so you can get a feel + + align:start position:0% +still playing out so you can get a feel + + + align:start position:0% +still playing out so you can get a feel +for what these things look like we kind + + align:start position:0% +for what these things look like we kind + + + align:start position:0% +for what these things look like we kind +of know they're real + + align:start position:0% +of know they're real + + + align:start position:0% +of know they're real +right this is not just some solo + + align:start position:0% +right this is not just some solo + + + align:start position:0% +right this is not just some solo +construct we feel these because we see + + align:start position:0% +construct we feel these because we see + + + align:start position:0% +construct we feel these because we see +them around us so what's the pattern so + + align:start position:0% +them around us so what's the pattern so + + + align:start position:0% +them around us so what's the pattern so +there's a core technology advance that + + align:start position:0% +there's a core technology advance that + + + align:start position:0% +there's a core technology advance that +yields opportunities for new + + align:start position:0% +yields opportunities for new + + + align:start position:0% +yields opportunities for new +applications which can pile on to that + + align:start position:0% +applications which can pile on to that + + + align:start position:0% +applications which can pile on to that +core technology advanced and then that + + align:start position:0% +core technology advanced and then that + + + align:start position:0% +core technology advanced and then that +in turn can become big enough that it + + align:start position:0% +in turn can become big enough that it + + + align:start position:0% +in turn can become big enough that it +enters society at scale right and we + + align:start position:0% +enters society at scale right and we + + + align:start position:0% +enters society at scale right and we +also the IT revolution spreading into + + align:start position:0% +also the IT revolution spreading into + + + align:start position:0% +also the IT revolution spreading into +different parts of the economy and then + + align:start position:0% +different parts of the economy and then + + + align:start position:0% +different parts of the economy and then +that can yield productivity gain so + + align:start position:0% +that can yield productivity gain so + + + align:start position:0% +that can yield productivity gain so +productivity gains for you non + + align:start position:0% +productivity gains for you non + + + align:start position:0% +productivity gains for you non +economists are when you're producing + + align:start position:0% +economists are when you're producing + + + align:start position:0% +economists are when you're producing +more with less labor input so more for + + align:start position:0% +more with less labor input so more for + + + align:start position:0% +more with less labor input so more for +less + + align:start position:0% +less + + + align:start position:0% +less +right workers spend less time on the + + align:start position:0% +right workers spend less time on the + + + align:start position:0% +right workers spend less time on the +production stage and they produce more + + align:start position:0% +production stage and they produce more + + + align:start position:0% +production stage and they produce more +right so those are the efficiencies that + + align:start position:0% +right so those are the efficiencies that + + + align:start position:0% +right so those are the efficiencies that +come out of technology enable these + + align:start position:0% +come out of technology enable these + + + align:start position:0% +come out of technology enable these +productivity gains the productivity + + align:start position:0% +productivity gains the productivity + + + align:start position:0% +productivity gains the productivity +gains that is a real gain in the society + + align:start position:0% +gains that is a real gain in the society + + + align:start position:0% +gains that is a real gain in the society +right that creates real wealth because + + align:start position:0% +right that creates real wealth because + + + align:start position:0% +right that creates real wealth because +you're producing more with less so + + align:start position:0% +you're producing more with less so + + + align:start position:0% +you're producing more with less so +there's a real game and then depending + + align:start position:0% +there's a real game and then depending + + + align:start position:0% +there's a real game and then depending +on how your societies organized you can + + align:start position:0% +on how your societies organized you can + + + align:start position:0% +on how your societies organized you can +distribute that wealth and the society + + align:start position:0% +distribute that wealth and the society + + + align:start position:0% +distribute that wealth and the society +can move ahead so that's what we saw + + align:start position:0% +can move ahead so that's what we saw + + + align:start position:0% +can move ahead so that's what we saw +happening in that amazing 1990s period + + align:start position:0% +happening in that amazing 1990s period + + + align:start position:0% +happening in that amazing 1990s period +right and we'll talk about Jorgenson and + + align:start position:0% +right and we'll talk about Jorgenson and + + + align:start position:0% +right and we'll talk about Jorgenson and +the pictures of that in a minute + + align:start position:0% +the pictures of that in a minute + + + align:start position:0% +the pictures of that in a minute +follow me you with me so great we're out + + align:start position:0% +follow me you with me so great we're out + + + align:start position:0% +follow me you with me so great we're out +of the dismal science there's really + + align:start position:0% +of the dismal science there's really + + + align:start position:0% +of the dismal science there's really +good news here you can do this + + align:start position:0% +good news here you can do this + + + align:start position:0% +good news here you can do this +innovation stuff and grow your society + + align:start position:0% +innovation stuff and grow your society + + + align:start position:0% +innovation stuff and grow your society +grow your economy and grow SAS Lydell + + align:start position:0% +grow your economy and grow SAS Lydell + + + align:start position:0% +grow your economy and grow SAS Lydell +well Bing right that's the good news the + + align:start position:0% +well Bing right that's the good news the + + + align:start position:0% +well Bing right that's the good news the +bad news is how the heck do you do that + + align:start position:0% +bad news is how the heck do you do that + + + align:start position:0% +bad news is how the heck do you do that +how do you do that and that's what this + + align:start position:0% +how do you do that and that's what this + + + align:start position:0% +how do you do that and that's what this +course is about how do you do that for a + + align:start position:0% +course is about how do you do that for a + + + align:start position:0% +course is about how do you do that for a +long time + + align:start position:0% +long time + + + align:start position:0% +long time +economists thought that this + + align:start position:0% +economists thought that this + + + align:start position:0% +economists thought that this +technological and unrelated innovation + + align:start position:0% +technological and unrelated innovation + + + align:start position:0% +technological and unrelated innovation +stuff was the way in which rich nations + + align:start position:0% +stuff was the way in which rich nations + + + align:start position:0% +stuff was the way in which rich nations +got much richer and that's pretty much + + align:start position:0% +got much richer and that's pretty much + + + align:start position:0% +got much richer and that's pretty much +the way it looked for a long period of + + align:start position:0% +the way it looked for a long period of + + + align:start position:0% +the way it looked for a long period of +time but then funny things started + + align:start position:0% +time but then funny things started + + + align:start position:0% +time but then funny things started +happening right countries like Korea + + align:start position:0% +happening right countries like Korea + + + align:start position:0% +happening right countries like Korea +Taiwan but then really importantly India + + align:start position:0% +Taiwan but then really importantly India + + + align:start position:0% +Taiwan but then really importantly India +and China hit on aspects of a + + align:start position:0% +and China hit on aspects of a + + + align:start position:0% +and China hit on aspects of a +technological based innovation model and + + align:start position:0% +technological based innovation model and + + + align:start position:0% +technological based innovation model and +began to significantly grow the middle + + align:start position:0% +began to significantly grow the middle + + + align:start position:0% +began to significantly grow the middle +classes in their society so we now know + + align:start position:0% +classes in their society so we now know + + + align:start position:0% +classes in their society so we now know +this is not only Malthus view this is + + align:start position:0% +this is not only Malthus view this is + + + align:start position:0% +this is not only Malthus view this is +not only a model for developed countries + + align:start position:0% +not only a model for developed countries + + + align:start position:0% +not only a model for developed countries +this is a developing country model - + + align:start position:0% +this is a developing country model - + + + align:start position:0% +this is a developing country model - +this is really important right + + align:start position:0% +this is really important right + + + align:start position:0% +this is really important right +so technological progress is key capital + + align:start position:0% +so technological progress is key capital + + + align:start position:0% +so technological progress is key capital +is a supporting role but still important + + align:start position:0% +is a supporting role but still important + + + align:start position:0% +is a supporting role but still important +right labor supply is a supporting role + + align:start position:0% +right labor supply is a supporting role + + + align:start position:0% +right labor supply is a supporting role +if it's still important and solo brings + + align:start position:0% +if it's still important and solo brings + + + align:start position:0% +if it's still important and solo brings +us this whole new set of ideas but then + + align:start position:0% +us this whole new set of ideas but then + + + align:start position:0% +us this whole new set of ideas but then +he runs into a problem because remember + + align:start position:0% +he runs into a problem because remember + + + align:start position:0% +he runs into a problem because remember +he's a neoclassical economist he wants + + align:start position:0% +he's a neoclassical economist he wants + + + align:start position:0% +he's a neoclassical economist he wants +to get down to a small number of + + align:start position:0% +to get down to a small number of + + + align:start position:0% +to get down to a small number of +variables that you really know right + + align:start position:0% +variables that you really know right + + + align:start position:0% +variables that you really know right +good luck with trying to understand an + + align:start position:0% +good luck with trying to understand an + + + align:start position:0% +good luck with trying to understand an +innovation system based upon + + align:start position:0% +innovation system based upon + + + align:start position:0% +innovation system based upon +mathematically proven small numbers of + + align:start position:0% +mathematically proven small numbers of + + + align:start position:0% +mathematically proven small numbers of +variables it is much too rich and + + align:start position:0% +variables it is much too rich and + + + align:start position:0% +variables it is much too rich and +complex system you can't put an + + align:start position:0% +complex system you can't put an + + + align:start position:0% +complex system you can't put an +innovation system in to supply and + + align:start position:0% +innovation system in to supply and + + + align:start position:0% +innovation system in to supply and +demand curves so Sola sees the power of + + align:start position:0% +demand curves so Sola sees the power of + + + align:start position:0% +demand curves so Sola sees the power of +technological advance but he doesn't see + + align:start position:0% +technological advance but he doesn't see + + + align:start position:0% +technological advance but he doesn't see +how to measure it + + align:start position:0% +how to measure it + + + align:start position:0% +how to measure it +so we can't put it into his neoclassical + + align:start position:0% +so we can't put it into his neoclassical + + + align:start position:0% +so we can't put it into his neoclassical +economic model so he treats + + align:start position:0% +economic model so he treats + + + align:start position:0% +economic model so he treats +technological innovation as exogenous + + align:start position:0% +technological innovation as exogenous + + + align:start position:0% +technological innovation as exogenous +outside of the economic analytical + + align:start position:0% +outside of the economic analytical + + + align:start position:0% +outside of the economic analytical +modeling process that he's involved in + + align:start position:0% +modeling process that he's involved in + + + align:start position:0% +modeling process that he's involved in +that's pretty amazing right when you + + align:start position:0% +that's pretty amazing right when you + + + align:start position:0% +that's pretty amazing right when you +think about it the guy figures out the + + align:start position:0% +think about it the guy figures out the + + + align:start position:0% +think about it the guy figures out the +dominant causative factor of growth + + align:start position:0% +dominant causative factor of growth + + + align:start position:0% +dominant causative factor of growth +which is needless to say a pretty + + align:start position:0% +which is needless to say a pretty + + + align:start position:0% +which is needless to say a pretty +important thing in economics and then he + + align:start position:0% +important thing in economics and then he + + + align:start position:0% +important thing in economics and then he +can't play with it right because it's + + align:start position:0% +can't play with it right because it's + + + align:start position:0% +can't play with it right because it's +outside his system so that brings us to + + align:start position:0% +outside his system so that brings us to + + + align:start position:0% +outside his system so that brings us to +this character and this is Paul Romer + + align:start position:0% +this character and this is Paul Romer + + + align:start position:0% +this character and this is Paul Romer +and you can see you know very California + + align:start position:0% +and you can see you know very California + + + align:start position:0% +and you can see you know very California +right and he's got that laid book laid + + align:start position:0% +right and he's got that laid book laid + + + align:start position:0% +right and he's got that laid book laid +back kind of relaxed look in his eyes + + align:start position:0% +back kind of relaxed look in his eyes + + + align:start position:0% +back kind of relaxed look in his eyes +and he's he is a remarkable figure he is + + align:start position:0% +and he's he is a remarkable figure he is + + + align:start position:0% +and he's he is a remarkable figure he is +a maverick trouble maker + + align:start position:0% + + + + align:start position:0% + +you know I got to know him by actually + + align:start position:0% +you know I got to know him by actually + + + align:start position:0% +you know I got to know him by actually +working on some legislation with him + + align:start position:0% +working on some legislation with him + + + align:start position:0% +working on some legislation with him +back when I was working in the Senate + + align:start position:0% +back when I was working in the Senate + + + align:start position:0% +back when I was working in the Senate +and you know we knew we needed to + + align:start position:0% +and you know we knew we needed to + + + align:start position:0% +and you know we knew we needed to +improve the STEM education science and + + align:start position:0% +improve the STEM education science and + + + align:start position:0% +improve the STEM education science and +technology work base that was going to + + align:start position:0% +technology work base that was going to + + + align:start position:0% +technology work base that was going to +be pretty important for reasons I'll + + align:start position:0% +be pretty important for reasons I'll + + + align:start position:0% +be pretty important for reasons I'll +explain in a minute and how would you do + + align:start position:0% +explain in a minute and how would you do + + + align:start position:0% +explain in a minute and how would you do +that right so I'm a Senate staffer I'm + + align:start position:0% +that right so I'm a Senate staffer I'm + + + align:start position:0% +that right so I'm a Senate staffer I'm +thinking gee were already spending you + + align:start position:0% +thinking gee were already spending you + + + align:start position:0% +thinking gee were already spending you +know X billions of dollars on + + align:start position:0% +know X billions of dollars on + + + align:start position:0% +know X billions of dollars on +fellowships for you guys and you know + + align:start position:0% +fellowships for you guys and you know + + + align:start position:0% +fellowships for you guys and you know +then we're gonna have to find billions + + align:start position:0% +then we're gonna have to find billions + + + align:start position:0% +then we're gonna have to find billions +more and increase the number and expand + + align:start position:0% +more and increase the number and expand + + + align:start position:0% +more and increase the number and expand +the base and it's gonna be incredibly + + align:start position:0% +the base and it's gonna be incredibly + + + align:start position:0% +the base and it's gonna be incredibly +costly and I never get this past so you + + align:start position:0% +costly and I never get this past so you + + + align:start position:0% +costly and I never get this past so you +know rumor is thinking about all this + + align:start position:0% +know rumor is thinking about all this + + + align:start position:0% +know rumor is thinking about all this +stuff and writing about it and we'll + + align:start position:0% +stuff and writing about it and we'll + + + align:start position:0% +stuff and writing about it and we'll +read something else of his late in the + + align:start position:0% +read something else of his late in the + + + align:start position:0% +read something else of his late in the +class but sit down with him and I said + + align:start position:0% +class but sit down with him and I said + + + align:start position:0% +class but sit down with him and I said +bill none of you know you're not + + align:start position:0% +bill none of you know you're not + + + align:start position:0% +bill none of you know you're not +thinking about this right said think + + align:start position:0% +thinking about this right said think + + + align:start position:0% +thinking about this right said think +like an economist said you don't have to + + align:start position:0% +like an economist said you don't have to + + + align:start position:0% +like an economist said you don't have to +subsidize everything he just bribed the + + align:start position:0% +subsidize everything he just bribed the + + + align:start position:0% +subsidize everything he just bribed the +gatekeepers right that was his phrase + + align:start position:0% +gatekeepers right that was his phrase + + + align:start position:0% +gatekeepers right that was his phrase +and his point was you don't have to + + align:start position:0% +and his point was you don't have to + + + align:start position:0% +and his point was you don't have to +throw a huge amount of money and build + + align:start position:0% +throw a huge amount of money and build + + + align:start position:0% +throw a huge amount of money and build +up all kinds of programmatic elements + + align:start position:0% +up all kinds of programmatic elements + + + align:start position:0% +up all kinds of programmatic elements +you just figure out who's not doing + + align:start position:0% +you just figure out who's not doing + + + align:start position:0% +you just figure out who's not doing +their job and expanding the number of + + align:start position:0% +their job and expanding the number of + + + align:start position:0% +their job and expanding the number of +scientists and engineers studying at + + align:start position:0% +scientists and engineers studying at + + + align:start position:0% +scientists and engineers studying at +universities and you bribed them to + + align:start position:0% +universities and you bribed them to + + + align:start position:0% +universities and you bribed them to +change their ways that's the way you do + + align:start position:0% +change their ways that's the way you do + + + align:start position:0% +change their ways that's the way you do +it right much cheaper and sure enough we + + align:start position:0% +it right much cheaper and sure enough we + + + align:start position:0% +it right much cheaper and sure enough we +fashioned legislation and eventually get + + align:start position:0% +fashioned legislation and eventually get + + + align:start position:0% +fashioned legislation and eventually get +it passed I'm not sure it changed all + + align:start position:0% +it passed I'm not sure it changed all + + + align:start position:0% +it passed I'm not sure it changed all +that much but it was a fun exercise + + align:start position:0% +that much but it was a fun exercise + + + align:start position:0% +that much but it was a fun exercise +working with him because he definitely + + align:start position:0% +working with him because he definitely + + + align:start position:0% +working with him because he definitely +has this maverick troublemaking + + align:start position:0% +has this maverick troublemaking + + + align:start position:0% +has this maverick troublemaking +perspective at one point in his career + + align:start position:0% +perspective at one point in his career + + + align:start position:0% +perspective at one point in his career +at Stanford he he realizes the + + align:start position:0% +at Stanford he he realizes the + + + align:start position:0% +at Stanford he he realizes the +incredible inefficiency of economics + + align:start position:0% +incredible inefficiency of economics + + + align:start position:0% +incredible inefficiency of economics +education that his students just aren't + + align:start position:0% +education that his students just aren't + + + align:start position:0% +education that his students just aren't +getting the big ideas by listening to + + align:start position:0% +getting the big ideas by listening to + + + align:start position:0% +getting the big ideas by listening to +lectures and reading textbooks it's just + + align:start position:0% +lectures and reading textbooks it's just + + + align:start position:0% +lectures and reading textbooks it's just +not happening so he walks out of + + align:start position:0% +not happening so he walks out of + + + align:start position:0% +not happening so he walks out of +Stanford and sets up his own economics + + align:start position:0% +Stanford and sets up his own economics + + + align:start position:0% +Stanford and sets up his own economics +textbook company which is anti textbook + + align:start position:0% +textbook company which is anti textbook + + + align:start position:0% +textbook company which is anti textbook +right and essentially develops a whole + + align:start position:0% +right and essentially develops a whole + + + align:start position:0% +right and essentially develops a whole +set of modules of learn + + align:start position:0% +set of modules of learn + + + align:start position:0% +set of modules of learn +by doing exercises and problem sets and + + align:start position:0% +by doing exercises and problem sets and + + + align:start position:0% +by doing exercises and problem sets and +online elements right and so you don't + + align:start position:0% +online elements right and so you don't + + + align:start position:0% +online elements right and so you don't +get a textbook yeah you get something + + align:start position:0% +get a textbook yeah you get something + + + align:start position:0% +get a textbook yeah you get something +with the textbook but you get all kinds + + align:start position:0% +with the textbook but you get all kinds + + + align:start position:0% +with the textbook but you get all kinds +of online pieces that you do constantly + + align:start position:0% +of online pieces that you do constantly + + + align:start position:0% +of online pieces that you do constantly +and getting through this so he + + align:start position:0% +and getting through this so he + + + align:start position:0% +and getting through this so he +completely blew up the whole economics + + align:start position:0% +completely blew up the whole economics + + + align:start position:0% +completely blew up the whole economics +textbook industry and has forced an + + align:start position:0% +textbook industry and has forced an + + + align:start position:0% +textbook industry and has forced an +absolutely fundamental reform and then + + align:start position:0% +absolutely fundamental reform and then + + + align:start position:0% +absolutely fundamental reform and then +he went out and proved yes my new system + + align:start position:0% +he went out and proved yes my new system + + + align:start position:0% +he went out and proved yes my new system +here works better than Paul Samuelson's + + align:start position:0% +here works better than Paul Samuelson's + + + align:start position:0% +here works better than Paul Samuelson's +and everybody else's textbooks because + + align:start position:0% +and everybody else's textbooks because + + + align:start position:0% +and everybody else's textbooks because +people are absorbing the core ideas and + + align:start position:0% +people are absorbing the core ideas and + + + align:start position:0% +people are absorbing the core ideas and +be able to work with them much more + + align:start position:0% +be able to work with them much more + + + align:start position:0% +be able to work with them much more +efficiently it's a whole learning by + + align:start position:0% +efficiently it's a whole learning by + + + align:start position:0% +efficiently it's a whole learning by +doing problem-based learning set that he + + align:start position:0% +doing problem-based learning set that he + + + align:start position:0% +doing problem-based learning set that he +brings in economics so you know he just + + align:start position:0% +brings in economics so you know he just + + + align:start position:0% +brings in economics so you know he just +walks out of his economics job at + + align:start position:0% +walks out of his economics job at + + + align:start position:0% +walks out of his economics job at +Stanford and does this for four years so + + align:start position:0% +Stanford and does this for four years so + + + align:start position:0% +Stanford and does this for four years so +he's and now he's on the latest of his + + align:start position:0% +he's and now he's on the latest of his + + + align:start position:0% +he's and now he's on the latest of his +exercises which is he's walked out if he + + align:start position:0% +exercises which is he's walked out if he + + + align:start position:0% +exercises which is he's walked out if he +went to NYU a few years ago to work on + + align:start position:0% +went to NYU a few years ago to work on + + + align:start position:0% +went to NYU a few years ago to work on +sort of cluster development theory and + + align:start position:0% +sort of cluster development theory and + + + align:start position:0% +sort of cluster development theory and +cities in metropolitan areas and growth + + align:start position:0% +cities in metropolitan areas and growth + + + align:start position:0% +cities in metropolitan areas and growth +but then he left that so he's now chief + + align:start position:0% +but then he left that so he's now chief + + + align:start position:0% +but then he left that so he's now chief +economist for the World Bank and look + + align:start position:0% +economist for the World Bank and look + + + align:start position:0% +economist for the World Bank and look +out right this there's gonna be trouble + + align:start position:0% +out right this there's gonna be trouble + + + align:start position:0% +out right this there's gonna be trouble +ahead here he's gonna he's gonna change + + align:start position:0% +ahead here he's gonna he's gonna change + + + align:start position:0% +ahead here he's gonna he's gonna change +that place I'm confident but let's talk + + align:start position:0% +that place I'm confident but let's talk + + + align:start position:0% +that place I'm confident but let's talk +about the ideas that he brings to our + + align:start position:0% +about the ideas that he brings to our + + + align:start position:0% +about the ideas that he brings to our +problem this past summer I think that's + + align:start position:0% +problem this past summer I think that's + + + align:start position:0% +problem this past summer I think that's +when he started I haven't seen him since + + align:start position:0% +when he started I haven't seen him since + + + align:start position:0% +when he started I haven't seen him since +he started but sure enough one thing he + + align:start position:0% +he started but sure enough one thing he + + + align:start position:0% +he started but sure enough one thing he +does he writes this attack on economists + + align:start position:0% +does he writes this attack on economists + + + align:start position:0% +does he writes this attack on economists +saying they're completely in love with + + align:start position:0% +saying they're completely in love with + + + align:start position:0% +saying they're completely in love with +you know metrics and mathematics and + + align:start position:0% +you know metrics and mathematics and + + + align:start position:0% +you know metrics and mathematics and +it's not gonna get him anywhere these + + align:start position:0% +it's not gonna get him anywhere these + + + align:start position:0% +it's not gonna get him anywhere these +systems are too complex and it's just an + + align:start position:0% +systems are too complex and it's just an + + + align:start position:0% +systems are too complex and it's just an +assault on the profession because this + + align:start position:0% +assault on the profession because this + + + align:start position:0% +assault on the profession because this +is a profession like all professions it + + align:start position:0% +is a profession like all professions it + + + align:start position:0% +is a profession like all professions it +doesn't attack itself right this that's + + align:start position:0% +doesn't attack itself right this that's + + + align:start position:0% +doesn't attack itself right this that's +not polite right so Romer just you know + + align:start position:0% +not polite right so Romer just you know + + + align:start position:0% +not polite right so Romer just you know +lifts the veil of trouble and it's quite + + align:start position:0% +lifts the veil of trouble and it's quite + + + align:start position:0% +lifts the veil of trouble and it's quite +a piece it hasn't formally been + + align:start position:0% +a piece it hasn't formally been + + + align:start position:0% +a piece it hasn't formally been +published how much or any journal darest + + align:start position:0% +published how much or any journal darest + + + align:start position:0% +published how much or any journal darest +publish it but it's it's definitely + + align:start position:0% +publish it but it's it's definitely + + + align:start position:0% +publish it but it's it's definitely +circulating around I'll try and find it + + align:start position:0% +circulating around I'll try and find it + + + align:start position:0% +circulating around I'll try and find it +for you because it's a fun read it's + + align:start position:0% +for you because it's a fun read it's + + + align:start position:0% +for you because it's a fun read it's +really something + + align:start position:0% +really something + + + align:start position:0% +really something +anyway that's Romer and Romer is on this + + align:start position:0% +anyway that's Romer and Romer is on this + + + align:start position:0% +anyway that's Romer and Romer is on this +project his his famous 1990 piece which + + align:start position:0% +project his his famous 1990 piece which + + + align:start position:0% +project his his famous 1990 piece which +frankly probably should win him the + + align:start position:0% +frankly probably should win him the + + + align:start position:0% +frankly probably should win him the +Nobel Prize in Economics but he's such a + + align:start position:0% +Nobel Prize in Economics but he's such a + + + align:start position:0% +Nobel Prize in Economics but he's such a +troublemaker that it probably won't is + + align:start position:0% +troublemaker that it probably won't is + + + align:start position:0% +troublemaker that it probably won't is +called endogenous + + align:start position:0% +called endogenous + + + align:start position:0% +called endogenous +logical change so he's trying to reverse + + align:start position:0% +logical change so he's trying to reverse + + + align:start position:0% +logical change so he's trying to reverse +solos exogenous change and make it go + + align:start position:0% +solos exogenous change and make it go + + + align:start position:0% +solos exogenous change and make it go +back get these ideas of economic growth + + align:start position:0% +back get these ideas of economic growth + + + align:start position:0% +back get these ideas of economic growth +back into an economics thinking + + align:start position:0% +back into an economics thinking + + + align:start position:0% +back into an economics thinking +framework that's his project here right + + align:start position:0% +framework that's his project here right + + + align:start position:0% +framework that's his project here right +and he starts on this pathway so he + + align:start position:0% +and he starts on this pathway so he + + + align:start position:0% +and he starts on this pathway so he +agrees I mean let me just summarize the + + align:start position:0% +agrees I mean let me just summarize the + + + align:start position:0% +agrees I mean let me just summarize the +basic points he agrees was so low that + + align:start position:0% +basic points he agrees was so low that + + + align:start position:0% +basic points he agrees was so low that +growth is driven by technological change + + align:start position:0% +growth is driven by technological change + + + align:start position:0% +growth is driven by technological change +and then he argues that that in turn is + + align:start position:0% +and then he argues that that in turn is + + + align:start position:0% +and then he argues that that in turn is +driven by researchers who he describes + + align:start position:0% +driven by researchers who he describes + + + align:start position:0% +driven by researchers who he describes +as economic agents profit maximizing + + align:start position:0% +as economic agents profit maximizing + + + align:start position:0% +as economic agents profit maximizing +agents and then he looks at how + + align:start position:0% +agents and then he looks at how + + + align:start position:0% +agents and then he looks at how +technology isn't really a conventional + + align:start position:0% +technology isn't really a conventional + + + align:start position:0% +technology isn't really a conventional +good in the normal sense of economic + + align:start position:0% +good in the normal sense of economic + + + align:start position:0% +good in the normal sense of economic +goods but it has its own set of unique + + align:start position:0% +goods but it has its own set of unique + + + align:start position:0% +goods but it has its own set of unique +properties that make it really quite + + align:start position:0% +properties that make it really quite + + + align:start position:0% +properties that make it really quite +different but most important for us he + + align:start position:0% +different but most important for us he + + + align:start position:0% +different but most important for us he +looks at when he calls human capital + + align:start position:0% +looks at when he calls human capital + + + align:start position:0% +looks at when he calls human capital +engaged in research in other words you + + align:start position:0% +engaged in research in other words you + + + align:start position:0% +engaged in research in other words you +don't just have to do R&D to loosely + + align:start position:0% +don't just have to do R&D to loosely + + + align:start position:0% +don't just have to do R&D to loosely +summarize so long you've got to have a + + align:start position:0% +summarize so long you've got to have a + + + align:start position:0% +summarize so long you've got to have a +talent base doing that R&D this whole + + align:start position:0% +talent base doing that R&D this whole + + + align:start position:0% +talent base doing that R&D this whole +project is to take all these concepts + + align:start position:0% +project is to take all these concepts + + + align:start position:0% +project is to take all these concepts +and move them into an endogenous theory + + align:start position:0% +and move them into an endogenous theory + + + align:start position:0% +and move them into an endogenous theory +of of growth so his growth model is + + align:start position:0% +of of growth so his growth model is + + + align:start position:0% +of of growth so his growth model is +similar to you know two solos he's + + align:start position:0% +similar to you know two solos he's + + + align:start position:0% +similar to you know two solos he's +picking up on solos work you know he + + align:start position:0% +picking up on solos work you know he + + + align:start position:0% +picking up on solos work you know he +sees that technological change is the + + align:start position:0% +sees that technological change is the + + + align:start position:0% +sees that technological change is the +heart of economic growth as we've + + align:start position:0% +heart of economic growth as we've + + + align:start position:0% +heart of economic growth as we've +discussed he sees that technological + + align:start position:0% +discussed he sees that technological + + + align:start position:0% +discussed he sees that technological +change occurs in turn in a large part + + align:start position:0% +change occurs in turn in a large part + + + align:start position:0% +change occurs in turn in a large part +because of people responding to market + + align:start position:0% +because of people responding to market + + + align:start position:0% +because of people responding to market +incentives again he's trying to get this + + align:start position:0% +incentives again he's trying to get this + + + align:start position:0% +incentives again he's trying to get this +into economic thinking and this + + align:start position:0% +into economic thinking and this + + + align:start position:0% +into economic thinking and this +technological knowledge which is + + align:start position:0% +technological knowledge which is + + + align:start position:0% +technological knowledge which is +instructions for working with materials + + align:start position:0% +instructions for working with materials + + + align:start position:0% +instructions for working with materials +is inherently different from other + + align:start position:0% +is inherently different from other + + + align:start position:0% +is inherently different from other +economic models so developing a new and + + align:start position:0% +economic models so developing a new and + + + align:start position:0% +economic models so developing a new and +better set of instructions he argues is + + align:start position:0% +better set of instructions he argues is + + + align:start position:0% +better set of instructions he argues is +a can be treated as a fixed cost in + + align:start position:0% +a can be treated as a fixed cost in + + + align:start position:0% +a can be treated as a fixed cost in +economic terms and it's therefore a + + align:start position:0% +economic terms and it's therefore a + + + align:start position:0% +economic terms and it's therefore a +defining characteristic economics + + align:start position:0% +defining characteristic economics + + + align:start position:0% +defining characteristic economics +characteristic of innovation so just for + + align:start position:0% +characteristic of innovation so just for + + + align:start position:0% +characteristic of innovation so just for +an example right I mean there's article + + align:start position:0% +an example right I mean there's article + + + align:start position:0% +an example right I mean there's article +is richer than this but I'll just cite a + + align:start position:0% +is richer than this but I'll just cite a + + + align:start position:0% +is richer than this but I'll just cite a +few examples of what he + + align:start position:0% +few examples of what he + + + align:start position:0% +few examples of what he +trying to think about a rival good is + + align:start position:0% +trying to think about a rival good is + + + align:start position:0% +trying to think about a rival good is +property that if used by one person or + + align:start position:0% +property that if used by one person or + + + align:start position:0% +property that if used by one person or +firm precludes use by another and a non + + align:start position:0% +firm precludes use by another and a non + + + align:start position:0% +firm precludes use by another and a non +rival good is a kind of property that if + + align:start position:0% +rival good is a kind of property that if + + + align:start position:0% +rival good is a kind of property that if +used by one person or firm in no way + + align:start position:0% +used by one person or firm in no way + + + align:start position:0% +used by one person or firm in no way +limits the use by the others so + + align:start position:0% +limits the use by the others so + + + align:start position:0% +limits the use by the others so +technology he argues is naturally + + align:start position:0% +technology he argues is naturally + + + align:start position:0% +technology he argues is naturally +non-rival right because it can be + + align:start position:0% +non-rival right because it can be + + + align:start position:0% +non-rival right because it can be +readily shared and adopted by others in + + align:start position:0% +readily shared and adopted by others in + + + align:start position:0% +readily shared and adopted by others in +other words once you see this thing and + + align:start position:0% +other words once you see this thing and + + + align:start position:0% +other words once you see this thing and +understand how it works then you can + + align:start position:0% +understand how it works then you can + + + align:start position:0% +understand how it works then you can +make your own version of it right but + + align:start position:0% +make your own version of it right but + + + align:start position:0% +make your own version of it right but +there's obviously an how would you get + + align:start position:0% +there's obviously an how would you get + + + align:start position:0% +there's obviously an how would you get +rich off this if it's completely non + + align:start position:0% +rich off this if it's completely non + + + align:start position:0% +rich off this if it's completely non +rival so capitalists move to make it + + align:start position:0% +rival so capitalists move to make it + + + align:start position:0% +rival so capitalists move to make it +excludable right where the owner of the + + align:start position:0% +excludable right where the owner of the + + + align:start position:0% +excludable right where the owner of the +good Steve Jobs and his crew try to + + align:start position:0% +good Steve Jobs and his crew try to + + + align:start position:0% +good Steve Jobs and his crew try to +prevent others from using it through for + + align:start position:0% +prevent others from using it through for + + + align:start position:0% +prevent others from using it through for +example through trade secret serve + + align:start position:0% +example through trade secret serve + + + align:start position:0% +example through trade secret serve +patents right so technology can be made + + align:start position:0% +patents right so technology can be made + + + align:start position:0% +patents right so technology can be made +partially excludable but in the end + + align:start position:0% +partially excludable but in the end + + + align:start position:0% +partially excludable but in the end +technology has these remember this term + + align:start position:0% +technology has these remember this term + + + align:start position:0% +technology has these remember this term +spillover features knowledge spillover + + align:start position:0% +spillover features knowledge spillover + + + align:start position:0% +spillover features knowledge spillover +features that make it pretty accessible + + align:start position:0% +features that make it pretty accessible + + + align:start position:0% +features that make it pretty accessible +because you get to see the technology + + align:start position:0% +because you get to see the technology + + + align:start position:0% +because you get to see the technology +and you can derive ideas about how its + + align:start position:0% +and you can derive ideas about how its + + + align:start position:0% +and you can derive ideas about how its +put together so technology is unlike any + + align:start position:0% +put together so technology is unlike any + + + align:start position:0% +put together so technology is unlike any +other kind of economic good because it + + align:start position:0% +other kind of economic good because it + + + align:start position:0% +other kind of economic good because it +can be both excludable and + + align:start position:0% +can be both excludable and + + + align:start position:0% +can be both excludable and +non-excludable rival and nonrival right + + align:start position:0% +non-excludable rival and nonrival right + + + align:start position:0% +non-excludable rival and nonrival right +it's not like anything else it's not + + align:start position:0% +it's not like anything else it's not + + + align:start position:0% +it's not like anything else it's not +like owning a farm right and you are mad + + align:start position:0% +like owning a farm right and you are mad + + + align:start position:0% +like owning a farm right and you are mad +max' good technology in general so he's + + align:start position:0% +max' good technology in general so he's + + + align:start position:0% +max' good technology in general so he's +developing a broader way of looking at + + align:start position:0% +developing a broader way of looking at + + + align:start position:0% +developing a broader way of looking at +this whole category all right so that's + + align:start position:0% +this whole category all right so that's + + + align:start position:0% +this whole category all right so that's +one I core idea let's try and develop + + align:start position:0% +one I core idea let's try and develop + + + align:start position:0% +one I core idea let's try and develop +theories of economics that by which we + + align:start position:0% +theories of economics that by which we + + + align:start position:0% +theories of economics that by which we +can better describe what technology is + + align:start position:0% +can better describe what technology is + + + align:start position:0% +can better describe what technology is +since it's so key to growth but his + + align:start position:0% +since it's so key to growth but his + + + align:start position:0% +since it's so key to growth but his +really important contribution is around + + align:start position:0% +really important contribution is around + + + align:start position:0% +really important contribution is around +the role of human capital and that's + + align:start position:0% +the role of human capital and that's + + + align:start position:0% +the role of human capital and that's +what I want you to really remember today + + align:start position:0% + + + + align:start position:0% + +not gonna explain this so it's Rome + + align:start position:0% +not gonna explain this so it's Rome + + + align:start position:0% +not gonna explain this so it's Rome +right whatever it is 200 right it's + + align:start position:0% +right whatever it is 200 right it's + + + align:start position:0% +right whatever it is 200 right it's +wrong and Romans they're terrific + + align:start position:0% +wrong and Romans they're terrific + + + align:start position:0% +wrong and Romans they're terrific +engineers they figured out these amazing + + align:start position:0% +engineers they figured out these amazing + + + align:start position:0% +engineers they figured out these amazing +roads right and they stuck them around + + align:start position:0% +roads right and they stuck them around + + + align:start position:0% +roads right and they stuck them around +all over Europe and that's a technology + + align:start position:0% +all over Europe and that's a technology + + + align:start position:0% +all over Europe and that's a technology +advanced and it improves communication + + align:start position:0% +advanced and it improves communication + + + align:start position:0% +advanced and it improves communication +systems and transports so it carries + + align:start position:0% +systems and transports so it carries + + + align:start position:0% +systems and transports so it carries +with it its technological advance that + + align:start position:0% +with it its technological advance that + + + align:start position:0% +with it its technological advance that +carries with it some game now the width + + align:start position:0% +carries with it some game now the width + + + align:start position:0% +carries with it some game now the width +of the Roman Road is the defining + + align:start position:0% +of the Roman Road is the defining + + + align:start position:0% +of the Roman Road is the defining +characteristic of the width of railroads + + align:start position:0% +characteristic of the width of railroads + + + align:start position:0% +characteristic of the width of railroads +right that's the width that's the + + align:start position:0% +right that's the width that's the + + + align:start position:0% +right that's the width that's the +distance between the rail rails is + + align:start position:0% +distance between the rail rails is + + + align:start position:0% +distance between the rail rails is +defined by the Roman Road distances + + align:start position:0% +defined by the Roman Road distances + + + align:start position:0% +defined by the Roman Road distances +interestingly enough the Romans had a + + align:start position:0% +interestingly enough the Romans had a + + + align:start position:0% +interestingly enough the Romans had a +very primitive kind of toy steam engine + + align:start position:0% +very primitive kind of toy steam engine + + + align:start position:0% +very primitive kind of toy steam engine +that Roman kids would play with and you + + align:start position:0% +that Roman kids would play with and you + + + align:start position:0% +that Roman kids would play with and you +know it had an axle and had this you + + align:start position:0% +know it had an axle and had this you + + + align:start position:0% +know it had an axle and had this you +know little you heated up with a candle + + align:start position:0% +know little you heated up with a candle + + + align:start position:0% +know little you heated up with a candle +or something and then this little thing + + align:start position:0% +or something and then this little thing + + + align:start position:0% +or something and then this little thing +would spin around puffing away because + + align:start position:0% +would spin around puffing away because + + + align:start position:0% +would spin around puffing away because +it would you know water would boil and + + align:start position:0% +it would you know water would boil and + + + align:start position:0% +it would you know water would boil and +so forth and would sort of spin around + + align:start position:0% +so forth and would sort of spin around + + + align:start position:0% +so forth and would sort of spin around +Romer would say that the reason why + + align:start position:0% +Romer would say that the reason why + + + align:start position:0% +Romer would say that the reason why +Romans didn't take the step of putting + + align:start position:0% +Romans didn't take the step of putting + + + align:start position:0% +Romans didn't take the step of putting +rails on their roads and sticking the + + align:start position:0% +rails on their roads and sticking the + + + align:start position:0% +rails on their roads and sticking the +steam engines on the rails was that they + + align:start position:0% +steam engines on the rails was that they + + + align:start position:0% +steam engines on the rails was that they +did not have enough human capital + + align:start position:0% +did not have enough human capital + + + align:start position:0% +did not have enough human capital +engaged in research in other words they + + align:start position:0% +engaged in research in other words they + + + align:start position:0% +engaged in research in other words they +didn't have a big enough group of people + + align:start position:0% +didn't have a big enough group of people + + + align:start position:0% +didn't have a big enough group of people +that were talented and well-educated + + align:start position:0% +that were talented and well-educated + + + align:start position:0% +that were talented and well-educated +that were figuring out how to move this + + align:start position:0% +that were figuring out how to move this + + + align:start position:0% +that were figuring out how to move this +toy steam system to an actual technology + + align:start position:0% +toy steam system to an actual technology + + + align:start position:0% +toy steam system to an actual technology +advanced you know moving through the + + align:start position:0% +advanced you know moving through the + + + align:start position:0% +advanced you know moving through the +innovation and invention and innovation + + align:start position:0% +innovation and invention and innovation + + + align:start position:0% +innovation and invention and innovation +stages so the human human capital + + align:start position:0% +stages so the human human capital + + + align:start position:0% +stages so the human human capital +engaged in research would have been was + + align:start position:0% +engaged in research would have been was + + + align:start position:0% +engaged in research would have been was +the critical determinant factor about + + align:start position:0% +the critical determinant factor about + + + align:start position:0% +the critical determinant factor about +why they didn't put these pieces + + align:start position:0% +why they didn't put these pieces + + + align:start position:0% +why they didn't put these pieces +together right so it's not just doing a + + align:start position:0% +together right so it's not just doing a + + + align:start position:0% +together right so it's not just doing a +bunch of research + + align:start position:0% +bunch of research + + + align:start position:0% +bunch of research +you've got to have the talent base doing + + align:start position:0% +you've got to have the talent base doing + + + align:start position:0% +you've got to have the talent base doing +that research and that that will be a + + align:start position:0% +that research and that that will be a + + + align:start position:0% +that research and that that will be a +determining factor in whether or not + + align:start position:0% +determining factor in whether or not + + + align:start position:0% +determining factor in whether or not +you're going to get to the stage of + + align:start position:0% +you're going to get to the stage of + + + align:start position:0% +you're going to get to the stage of +technological advance so you follow me + + align:start position:0% +technological advance so you follow me + + + align:start position:0% +technological advance so you follow me +so it's again that phrasing is human + + align:start position:0% +so it's again that phrasing is human + + + align:start position:0% +so it's again that phrasing is human +capital engagement research if you lack + + align:start position:0% +capital engagement research if you lack + + + align:start position:0% +capital engagement research if you lack +human capital engaged in research you + + align:start position:0% +human capital engaged in research you + + + align:start position:0% +human capital engaged in research you +get economic stagnation all right let's + + align:start position:0% +get economic stagnation all right let's + + + align:start position:0% +get economic stagnation all right let's +do another picture medieval Europe right + + align:start position:0% +do another picture medieval Europe right + + + align:start position:0% +do another picture medieval Europe right +let's face it there's no human capital + + align:start position:0% +let's face it there's no human capital + + + align:start position:0% +let's face it there's no human capital +engagement research maybe a few + + align:start position:0% +engagement research maybe a few + + + align:start position:0% +engagement research maybe a few +alchemists you know poking around in + + align:start position:0% +alchemists you know poking around in + + + align:start position:0% +alchemists you know poking around in +dungeons right that's it all right so + + align:start position:0% +dungeons right that's it all right so + + + align:start position:0% +dungeons right that's it all right so +what is their economic growth in + + align:start position:0% +what is their economic growth in + + + align:start position:0% +what is their economic growth in +medieval Europe not really right I mean + + align:start position:0% +medieval Europe not really right I mean + + + align:start position:0% +medieval Europe not really right I mean +they learn something about castle + + align:start position:0% +they learn something about castle + + + align:start position:0% +they learn something about castle +building but a lot of that came from the + + align:start position:0% +building but a lot of that came from the + + + align:start position:0% +building but a lot of that came from the +Romans anyway economic growth basically + + align:start position:0% +Romans anyway economic growth basically + + + align:start position:0% +Romans anyway economic growth basically +consisted of you know hiring a + + align:start position:0% +consisted of you know hiring a + + + align:start position:0% +consisted of you know hiring a +motorcycle gang and you know putting on + + align:start position:0% +motorcycle gang and you know putting on + + + align:start position:0% +motorcycle gang and you know putting on +a horses and riding over to the next + + align:start position:0% +a horses and riding over to the next + + + align:start position:0% +a horses and riding over to the next +guy's castle and looting the place + + align:start position:0% +guy's castle and looting the place + + + align:start position:0% +guy's castle and looting the place +that's how you got gained right that was + + align:start position:0% +that's how you got gained right that was + + + align:start position:0% +that's how you got gained right that was +the economic growth model it was + + align:start position:0% +the economic growth model it was + + + align:start position:0% +the economic growth model it was +stealing right it was like piracy right + + align:start position:0% +stealing right it was like piracy right + + + align:start position:0% +stealing right it was like piracy right +there was no economic growth model so + + align:start position:0% +there was no economic growth model so + + + align:start position:0% +there was no economic growth model so +it's not until the Industrial Revolution + + align:start position:0% +it's not until the Industrial Revolution + + + align:start position:0% +it's not until the Industrial Revolution +that you get a significant amount of + + align:start position:0% +that you get a significant amount of + + + align:start position:0% +that you get a significant amount of +human capital engaged in research that's + + align:start position:0% +human capital engaged in research that's + + + align:start position:0% +human capital engaged in research that's +going to be able to nurture these + + align:start position:0% +going to be able to nurture these + + + align:start position:0% +going to be able to nurture these +technology advances so we know we have + + align:start position:0% +technology advances so we know we have + + + align:start position:0% +technology advances so we know we have +our second innovation factor now the + + align:start position:0% +our second innovation factor now the + + + align:start position:0% +our second innovation factor now the +first factor solo and again I'm + + align:start position:0% +first factor solo and again I'm + + + align:start position:0% +first factor solo and again I'm +summarizing here you got to do R&D right + + align:start position:0% +summarizing here you got to do R&D right + + + align:start position:0% +summarizing here you got to do R&D right +technological and related innovation you + + align:start position:0% +technological and related innovation you + + + align:start position:0% +technological and related innovation you +got to do some R&D Romer second factor + + align:start position:0% +got to do some R&D Romer second factor + + + align:start position:0% +got to do some R&D Romer second factor +human capital engagement research you + + align:start position:0% +human capital engagement research you + + + align:start position:0% +human capital engagement research you +kind of have the talent base behind that + + align:start position:0% +kind of have the talent base behind that + + + align:start position:0% +kind of have the talent base behind that +or indecent behind that technological + + align:start position:0% +or indecent behind that technological + + + align:start position:0% +or indecent behind that technological +advance is going to be the talent base + + align:start position:0% +advance is going to be the talent base + + + align:start position:0% +advance is going to be the talent base +so that gives us two factors and you + + align:start position:0% +so that gives us two factors and you + + + align:start position:0% +so that gives us two factors and you +guys can now look at any country or a + + align:start position:0% +guys can now look at any country or a + + + align:start position:0% +guys can now look at any country or a +society or region and you can now say oh + + align:start position:0% +society or region and you can now say oh + + + align:start position:0% +society or region and you can now say oh +I can start to look at that I can look + + align:start position:0% +I can start to look at that I can look + + + align:start position:0% +I can start to look at that I can look +at hey are they doing + + align:start position:0% +at hey are they doing + + + align:start position:0% +at hey are they doing +a bunch of R&D and to what's their + + align:start position:0% +a bunch of R&D and to what's their + + + align:start position:0% +a bunch of R&D and to what's their +talent base like right Romer develops + + align:start position:0% +talent base like right Romer develops + + + align:start position:0% +talent base like right Romer develops +something that he calls prospector + + align:start position:0% +something that he calls prospector + + + align:start position:0% +something that he calls prospector +theory now that's not in this reading + + align:start position:0% +theory now that's not in this reading + + + align:start position:0% +theory now that's not in this reading +since some of us somewhat later work but + + align:start position:0% +since some of us somewhat later work but + + + align:start position:0% +since some of us somewhat later work but +it's a really it's an intriguing idea + + align:start position:0% +it's a really it's an intriguing idea + + + align:start position:0% +it's a really it's an intriguing idea +and it's very simple and straightforward + + align:start position:0% +and it's very simple and straightforward + + + align:start position:0% +and it's very simple and straightforward +but it'll help you in making these + + align:start position:0% +but it'll help you in making these + + + align:start position:0% +but it'll help you in making these +assessments so Romer looks at the + + align:start position:0% +assessments so Romer looks at the + + + align:start position:0% +assessments so Romer looks at the +chemical engineering industry in Europe + + align:start position:0% +chemical engineering industry in Europe + + + align:start position:0% +chemical engineering industry in Europe +in the late 1800s and he notices that + + align:start position:0% +in the late 1800s and he notices that + + + align:start position:0% +in the late 1800s and he notices that +there are two countries that dominate + + align:start position:0% +there are two countries that dominate + + + align:start position:0% +there are two countries that dominate +these early chemical industries Germany + + align:start position:0% +these early chemical industries Germany + + + align:start position:0% +these early chemical industries Germany +and Britain they have the big emerging + + align:start position:0% +and Britain they have the big emerging + + + align:start position:0% +and Britain they have the big emerging +chemical industries and other countries + + align:start position:0% +chemical industries and other countries + + + align:start position:0% +chemical industries and other countries +are doing stuff in this area they don't + + align:start position:0% +are doing stuff in this area they don't + + + align:start position:0% +are doing stuff in this area they don't +have anything like what Germany and + + align:start position:0% +have anything like what Germany and + + + align:start position:0% +have anything like what Germany and +Britain are up to stemming looks behind + + align:start position:0% +Britain are up to stemming looks behind + + + align:start position:0% +Britain are up to stemming looks behind +those industries and finds that both + + align:start position:0% +those industries and finds that both + + + align:start position:0% +those industries and finds that both +Germany and Britain have very strong + + align:start position:0% +Germany and Britain have very strong + + + align:start position:0% +Germany and Britain have very strong +education systems for chemical engineers + + align:start position:0% +education systems for chemical engineers + + + align:start position:0% +education systems for chemical engineers +so they are creating a talent base that + + align:start position:0% +so they are creating a talent base that + + + align:start position:0% +so they are creating a talent base that +enables the advances that they are + + align:start position:0% +enables the advances that they are + + + align:start position:0% +enables the advances that they are +making in in chemical engineering so the + + align:start position:0% +making in in chemical engineering so the + + + align:start position:0% +making in in chemical engineering so the +idea is you got a field of prospectors + + align:start position:0% +idea is you got a field of prospectors + + + align:start position:0% +idea is you got a field of prospectors +so let's take it back to the origin of + + align:start position:0% +so let's take it back to the origin of + + + align:start position:0% +so let's take it back to the origin of +the idea so it's the California Gold + + align:start position:0% +the idea so it's the California Gold + + + align:start position:0% +the idea so it's the California Gold +Rush and it's 1848 it's not 18-49 yet + + align:start position:0% +Rush and it's 1848 it's not 18-49 yet + + + align:start position:0% +Rush and it's 1848 it's not 18-49 yet +right it's 1848 and you've got you know + + align:start position:0% +right it's 1848 and you've got you know + + + align:start position:0% +right it's 1848 and you've got you know +five or six people hanging around the + + align:start position:0% +five or six people hanging around the + + + align:start position:0% +five or six people hanging around the +Sacramento River occasionally sticking a + + align:start position:0% +Sacramento River occasionally sticking a + + + align:start position:0% +Sacramento River occasionally sticking a +pan into the river + + align:start position:0% +pan into the river + + + align:start position:0% +pan into the river +alright then a year later 18-49 + + align:start position:0% +alright then a year later 18-49 + + + align:start position:0% +alright then a year later 18-49 +you've got 250,000 people sticking pans + + align:start position:0% +you've got 250,000 people sticking pans + + + align:start position:0% +you've got 250,000 people sticking pans +into the Sacramento River and every + + align:start position:0% +into the Sacramento River and every + + + align:start position:0% +into the Sacramento River and every +trace of bowls you know part of that + + align:start position:0% +trace of bowls you know part of that + + + align:start position:0% +trace of bowls you know part of that +river system up every Creek what do you + + align:start position:0% +river system up every Creek what do you + + + align:start position:0% +river system up every Creek what do you +think you find more gold with 250,000 + + align:start position:0% +think you find more gold with 250,000 + + + align:start position:0% +think you find more gold with 250,000 +people you bet + + align:start position:0% +people you bet + + + align:start position:0% +people you bet +right staggering amount of gold gets + + align:start position:0% +right staggering amount of gold gets + + + align:start position:0% +right staggering amount of gold gets +down that's prospector Theory + + align:start position:0% +down that's prospector Theory + + + align:start position:0% +down that's prospector Theory +in other words and it's a little more + + align:start position:0% +in other words and it's a little more + + + align:start position:0% +in other words and it's a little more +sophisticated than that but you're gonna + + align:start position:0% +sophisticated than that but you're gonna + + + align:start position:0% +sophisticated than that but you're gonna +find more gold if you've got more + + align:start position:0% +find more gold if you've got more + + + align:start position:0% +find more gold if you've got more +prospectors on the problem now you have + + align:start position:0% +prospectors on the problem now you have + + + align:start position:0% +prospectors on the problem now you have +to train those prospectors it can't be + + align:start position:0% +to train those prospectors it can't be + + + align:start position:0% +to train those prospectors it can't be +totally amateur hour it's much better if + + align:start position:0% +totally amateur hour it's much better if + + + align:start position:0% +totally amateur hour it's much better if +you have trained sophisticated + + align:start position:0% +you have trained sophisticated + + + align:start position:0% +you have trained sophisticated +prospectors like Britain in German + + align:start position:0% +prospectors like Britain in German + + + align:start position:0% +prospectors like Britain in German +Britain and Germany did with the + + align:start position:0% +Britain and Germany did with the + + + align:start position:0% +Britain and Germany did with the +chemical engineering sector so you need + + align:start position:0% +chemical engineering sector so you need + + + align:start position:0% +chemical engineering sector so you need +that human capital engaged in the + + align:start position:0% +that human capital engaged in the + + + align:start position:0% +that human capital engaged in the +research system if the human capital is + + align:start position:0% +research system if the human capital is + + + align:start position:0% +research system if the human capital is +driving cabs it doesn't do any good + + align:start position:0% +driving cabs it doesn't do any good + + + align:start position:0% +driving cabs it doesn't do any good +you've got to have that human capital + + align:start position:0% +you've got to have that human capital + + + align:start position:0% +you've got to have that human capital +engaged in that system of research so + + align:start position:0% +engaged in that system of research so + + + align:start position:0% +engaged in that system of research so +you can then now make a further + + align:start position:0% +you can then now make a further + + + align:start position:0% +you can then now make a further +extrapolation on what roamers thinking + + align:start position:0% +extrapolation on what roamers thinking + + + align:start position:0% +extrapolation on what roamers thinking +about right you have a way now of + + align:start position:0% +about right you have a way now of + + + align:start position:0% +about right you have a way now of +looking at fundamental strengths of + + align:start position:0% +looking at fundamental strengths of + + + align:start position:0% +looking at fundamental strengths of +innovation system its R&D system and the + + align:start position:0% +innovation system its R&D system and the + + + align:start position:0% +innovation system its R&D system and the +talent in that system + + align:start position:0% + + + + align:start position:0% + +questions + + align:start position:0% + + + + align:start position:0% + +two weeks don't disappear you include + + align:start position:0% +two weeks don't disappear you include + + + align:start position:0% +two weeks don't disappear you include +questions of include really good and + + align:start position:0% +questions of include really good and + + + align:start position:0% +questions of include really good and +timely point so if Romer is right and + + align:start position:0% +timely point so if Romer is right and + + + align:start position:0% +timely point so if Romer is right and +you want a large number of well-trained + + align:start position:0% +you want a large number of well-trained + + + align:start position:0% +you want a large number of well-trained +prospectors and you're fencing off + + align:start position:0% +prospectors and you're fencing off + + + align:start position:0% +prospectors and you're fencing off +significant parts you society from that + + align:start position:0% +significant parts you society from that + + + align:start position:0% +significant parts you society from that +prospector pool you're doing something + + align:start position:0% +prospector pool you're doing something + + + align:start position:0% +prospector pool you're doing something +really stupid right just fundamental + + align:start position:0% +really stupid right just fundamental + + + align:start position:0% +really stupid right just fundamental +isn't that that's how simple and + + align:start position:0% +isn't that that's how simple and + + + align:start position:0% +isn't that that's how simple and +straightforward prospector theory is + + align:start position:0% +straightforward prospector theory is + + + align:start position:0% +straightforward prospector theory is +right that's why what's been happening + + align:start position:0% +right that's why what's been happening + + + align:start position:0% +right that's why what's been happening +over the last few weeks makes me so + + align:start position:0% +over the last few weeks makes me so + + + align:start position:0% +over the last few weeks makes me so +nervous because the u.s. developed an + + align:start position:0% +nervous because the u.s. developed an + + + align:start position:0% +nervous because the u.s. developed an +innovation system that worked on + + align:start position:0% +innovation system that worked on + + + align:start position:0% +innovation system that worked on +encouraging talent from everywhere to + + align:start position:0% +encouraging talent from everywhere to + + + align:start position:0% +encouraging talent from everywhere to +come here and it's a huge innovation + + align:start position:0% +come here and it's a huge innovation + + + align:start position:0% +come here and it's a huge innovation +advantage right it's huge in other words + + align:start position:0% +advantage right it's huge in other words + + + align:start position:0% +advantage right it's huge in other words +if you're running an innovation system + + align:start position:0% +if you're running an innovation system + + + align:start position:0% +if you're running an innovation system +and sucking in talent from everywhere to + + align:start position:0% +and sucking in talent from everywhere to + + + align:start position:0% +and sucking in talent from everywhere to +help field it right to help staff it + + align:start position:0% +help field it right to help staff it + + + align:start position:0% +help field it right to help staff it +that's really interesting compared to + + align:start position:0% +that's really interesting compared to + + + align:start position:0% +that's really interesting compared to +running an innovation system where you + + align:start position:0% +running an innovation system where you + + + align:start position:0% +running an innovation system where you +put fences around your borders not very + + align:start position:0% +put fences around your borders not very + + + align:start position:0% +put fences around your borders not very +smart + + align:start position:0% +smart + + + align:start position:0% +smart +that's why 400 tech companies have + + align:start position:0% +that's why 400 tech companies have + + + align:start position:0% +that's why 400 tech companies have +joined the amicus brief in the case + + align:start position:0% +joined the amicus brief in the case + + + align:start position:0% +joined the amicus brief in the case +that's being argued today right because + + align:start position:0% +that's being argued today right because + + + align:start position:0% +that's being argued today right because +they understand this so there is a huge + + align:start position:0% +they understand this so there is a huge + + + align:start position:0% +they understand this so there is a huge +inclusion piece to this fundamental idea + + align:start position:0% +inclusion piece to this fundamental idea + + + align:start position:0% +inclusion piece to this fundamental idea +Russia yeah I don't think we're there + + align:start position:0% +Russia yeah I don't think we're there + + + align:start position:0% +Russia yeah I don't think we're there +yet that's it's always an important + + align:start position:0% +yet that's it's always an important + + + align:start position:0% +yet that's it's always an important +question does a society have too much + + align:start position:0% +question does a society have too much + + + align:start position:0% +question does a society have too much +innovation going on right and I think + + align:start position:0% +innovation going on right and I think + + + align:start position:0% +innovation going on right and I think +we're not remotely close to that I don't + + align:start position:0% +we're not remotely close to that I don't + + + align:start position:0% +we're not remotely close to that I don't +think we're close to that right in other + + align:start position:0% +think we're close to that right in other + + + align:start position:0% +think we're close to that right in other +words we've got if technological and + + align:start position:0% +words we've got if technological and + + + align:start position:0% +words we've got if technological and +related innovation is the key driver for + + align:start position:0% +related innovation is the key driver for + + + align:start position:0% +related innovation is the key driver for +growth and we've got you know 2% growth + + align:start position:0% +growth and we've got you know 2% growth + + + align:start position:0% +growth and we've got you know 2% growth +at the moment maybe improving the + + align:start position:0% +at the moment maybe improving the + + + align:start position:0% +at the moment maybe improving the +innovation system might be a way to + + align:start position:0% +innovation system might be a way to + + + align:start position:0% +innovation system might be a way to +improve our growth rate therefore one + + align:start position:0% +improve our growth rate therefore one + + + align:start position:0% +improve our growth rate therefore one +way of looking at that is to get more + + align:start position:0% +way of looking at that is to get more + + + align:start position:0% +way of looking at that is to get more +prospectors on the problem right so I + + align:start position:0% +prospectors on the problem right so I + + + align:start position:0% +prospectors on the problem right so I +mean that's a simple-minded idea but the + + align:start position:0% +mean that's a simple-minded idea but the + + + align:start position:0% +mean that's a simple-minded idea but the +prospector theory is pretty + + align:start position:0% +prospector theory is pretty + + + align:start position:0% +prospector theory is pretty +straightforward + + align:start position:0% + + + + align:start position:0% + +it's supposed to be didn't have too many + + align:start position:0% +it's supposed to be didn't have too many + + + align:start position:0% +it's supposed to be didn't have too many +Vikings + + align:start position:0% +Vikings + + + align:start position:0% +Vikings +I think we're just so far away from this + + align:start position:0% +I think we're just so far away from this + + + align:start position:0% +I think we're just so far away from this +that we it's it's not really worthy of + + align:start position:0% +that we it's it's not really worthy of + + + align:start position:0% +that we it's it's not really worthy of +thought I mean look periodically in the + + align:start position:0% +thought I mean look periodically in the + + + align:start position:0% +thought I mean look periodically in the +science community there's panic about + + align:start position:0% +science community there's panic about + + + align:start position:0% +science community there's panic about +heavens we've trained too many + + align:start position:0% +heavens we've trained too many + + + align:start position:0% +heavens we've trained too many +physicists right they're only going to + + align:start position:0% +physicists right they're only going to + + + align:start position:0% +physicists right they're only going to +be able to drive cabs right that we're + + align:start position:0% +be able to drive cabs right that we're + + + align:start position:0% +be able to drive cabs right that we're +over we're in an oversupply situation + + align:start position:0% +over we're in an oversupply situation + + + align:start position:0% +over we're in an oversupply situation +and every once in a while you get you + + align:start position:0% +and every once in a while you get you + + + align:start position:0% +and every once in a while you get you +know cycles that frankly largely + + align:start position:0% +know cycles that frankly largely + + + align:start position:0% +know cycles that frankly largely +resemble the business cycles that tell + + align:start position:0% +resemble the business cycles that tell + + + align:start position:0% +resemble the business cycles that tell +us that we're at those were we may be at + + align:start position:0% +us that we're at those were we may be at + + + align:start position:0% +us that we're at those were we may be at +those stages and panic hits the science + + align:start position:0% +those stages and panic hits the science + + + align:start position:0% +those stages and panic hits the science +community that we're over we're training + + align:start position:0% +community that we're over we're training + + + align:start position:0% +community that we're over we're training +too many numbers but if we go back and + + align:start position:0% +too many numbers but if we go back and + + + align:start position:0% +too many numbers but if we go back and +think about what we've been learning + + align:start position:0% +think about what we've been learning + + + align:start position:0% +think about what we've been learning +here which is that technological and + + align:start position:0% +here which is that technological and + + + align:start position:0% +here which is that technological and +related innovation is a dynamic factor + + align:start position:0% +related innovation is a dynamic factor + + + align:start position:0% +related innovation is a dynamic factor +in your society in your economy right it + + align:start position:0% +in your society in your economy right it + + + align:start position:0% +in your society in your economy right it +is core to the way in which you grow + + align:start position:0% +is core to the way in which you grow + + + align:start position:0% +is core to the way in which you grow +then the talent base is a dynamic factor + + align:start position:0% +then the talent base is a dynamic factor + + + align:start position:0% +then the talent base is a dynamic factor +too and you don't want to restrict a + + align:start position:0% +too and you don't want to restrict a + + + align:start position:0% +too and you don't want to restrict a +dynamic factor because you're gonna + + align:start position:0% +dynamic factor because you're gonna + + + align:start position:0% +dynamic factor because you're gonna +limit your dynamism right don't shut + + align:start position:0% +limit your dynamism right don't shut + + + align:start position:0% +limit your dynamism right don't shut +down dynamic factors let them thrive the + + align:start position:0% +down dynamic factors let them thrive the + + + align:start position:0% +down dynamic factors let them thrive the +key here is not the problem science has + + align:start position:0% +key here is not the problem science has + + + align:start position:0% +key here is not the problem science has +it's not able to extrapolate to a larger + + align:start position:0% +it's not able to extrapolate to a larger + + + align:start position:0% +it's not able to extrapolate to a larger +use of its talent base right just + + align:start position:0% +use of its talent base right just + + + align:start position:0% +use of its talent base right just +because there may not be enough jobs in + + align:start position:0% +because there may not be enough jobs in + + + align:start position:0% +because there may not be enough jobs in +formal academia for all of the + + align:start position:0% +formal academia for all of the + + + align:start position:0% +formal academia for all of the +scientists we're training doesn't mean + + align:start position:0% +scientists we're training doesn't mean + + + align:start position:0% +scientists we're training doesn't mean +that there aren't really important + + align:start position:0% +that there aren't really important + + + align:start position:0% +that there aren't really important +functions and roles they can play + + align:start position:0% +functions and roles they can play + + + align:start position:0% +functions and roles they can play +elsewhere right so two-thirds of US + + align:start position:0% +elsewhere right so two-thirds of US + + + align:start position:0% +elsewhere right so two-thirds of US +scientists and engineers are employed by + + align:start position:0% +scientists and engineers are employed by + + + align:start position:0% +scientists and engineers are employed by +manufacturing industries right that's + + align:start position:0% +manufacturing industries right that's + + + align:start position:0% +manufacturing industries right that's +where actually most of the jobs are + + align:start position:0% +where actually most of the jobs are + + + align:start position:0% +where actually most of the jobs are +right not in the Academy and yet the + + align:start position:0% +right not in the Academy and yet the + + + align:start position:0% +right not in the Academy and yet the +scientific community views it as oh it's + + align:start position:0% +scientific community views it as oh it's + + + align:start position:0% +scientific community views it as oh it's +the Academy and that's where the + + align:start position:0% +the Academy and that's where the + + + align:start position:0% +the Academy and that's where the +oversupply problem is but maybe the key + + align:start position:0% +oversupply problem is but maybe the key + + + align:start position:0% +oversupply problem is but maybe the key +here is equipping that talent base with + + align:start position:0% +here is equipping that talent base with + + + align:start position:0% +here is equipping that talent base with +a whole new set of tools that enable + + align:start position:0% +a whole new set of tools that enable + + + align:start position:0% +a whole new set of tools that enable +them to play a broader role than simply + + align:start position:0% +them to play a broader role than simply + + + align:start position:0% +them to play a broader role than simply +supporting an academy right maybe that + + align:start position:0% +supporting an academy right maybe that + + + align:start position:0% +supporting an academy right maybe that +would be a smarter talent based + + align:start position:0% +would be a smarter talent based + + + align:start position:0% +would be a smarter talent based +trainings idea right + + align:start position:0% +trainings idea right + + + align:start position:0% +trainings idea right +maybe you give him you know + + align:start position:0% +maybe you give him you know + + + align:start position:0% +maybe you give him you know +entrepreneurship classes so they can + + align:start position:0% +entrepreneurship classes so they can + + + align:start position:0% +entrepreneurship classes so they can +think about starting their own startups + + align:start position:0% +think about starting their own startups + + + align:start position:0% +think about starting their own startups +maybe they get business miners right so + + align:start position:0% +maybe they get business miners right so + + + align:start position:0% +maybe they get business miners right so +they can do startup stuff maybe they get + + align:start position:0% +they can do startup stuff maybe they get + + + align:start position:0% +they can do startup stuff maybe they get +other kinds of training that gives them + + align:start position:0% +other kinds of training that gives them + + + align:start position:0% +other kinds of training that gives them +additional skill sets in addition to + + align:start position:0% +additional skill sets in addition to + + + align:start position:0% +additional skill sets in addition to +kind of classical research skill sets I + + align:start position:0% +kind of classical research skill sets I + + + align:start position:0% +kind of classical research skill sets I +think that would probably be a better + + align:start position:0% +think that would probably be a better + + + align:start position:0% +think that would probably be a better +answer than attempting to restrict the + + align:start position:0% +answer than attempting to restrict the + + + align:start position:0% +answer than attempting to restrict the +supply the historical US growth rate is + + align:start position:0% +supply the historical US growth rate is + + + align:start position:0% +supply the historical US growth rate is +3% that's starting to look pretty good + + align:start position:0% +3% that's starting to look pretty good + + + align:start position:0% +3% that's starting to look pretty good +cuz we haven't been there for quite some + + align:start position:0% +cuz we haven't been there for quite some + + + align:start position:0% +cuz we haven't been there for quite some +time it makes a big difference you all + + align:start position:0% +time it makes a big difference you all + + + align:start position:0% +time it makes a big difference you all +probably don't remember this too well + + align:start position:0% +probably don't remember this too well + + + align:start position:0% +probably don't remember this too well +but the dynamic quality and feel of the + + align:start position:0% +but the dynamic quality and feel of the + + + align:start position:0% +but the dynamic quality and feel of the +US economy in the 1990s was very + + align:start position:0% +US economy in the 1990s was very + + + align:start position:0% +US economy in the 1990s was very +different the sense of opportunity that + + align:start position:0% +different the sense of opportunity that + + + align:start position:0% +different the sense of opportunity that +was there was very powerful and it was + + align:start position:0% +was there was very powerful and it was + + + align:start position:0% +was there was very powerful and it was +pretty pervasive about society and if + + align:start position:0% +pretty pervasive about society and if + + + align:start position:0% +pretty pervasive about society and if +technological and related innovation + + align:start position:0% +technological and related innovation + + + align:start position:0% +technological and related innovation +tries growth and it's key to our growth + + align:start position:0% +tries growth and it's key to our growth + + + align:start position:0% +tries growth and it's key to our growth +rate then we the task is not how do you + + align:start position:0% +rate then we the task is not how do you + + + align:start position:0% +rate then we the task is not how do you +shut that down but how do you get back + + align:start position:0% +shut that down but how do you get back + + + align:start position:0% +shut that down but how do you get back +to a higher level growth rate I'd argue + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +yeah I mean it's an interesting idea + + align:start position:0% +yeah I mean it's an interesting idea + + + align:start position:0% +yeah I mean it's an interesting idea +right and I do think that we do have too + + align:start position:0% +right and I do think that we do have too + + + align:start position:0% +right and I do think that we do have too +many empty kitchens at this point right + + align:start position:0% +many empty kitchens at this point right + + + align:start position:0% +many empty kitchens at this point right +that needs staffing up frankly they need + + align:start position:0% +that needs staffing up frankly they need + + + align:start position:0% +that needs staffing up frankly they need +a path to growth and you know getting to + + align:start position:0% +a path to growth and you know getting to + + + align:start position:0% +a path to growth and you know getting to +fourth generation nuclear power I mean + + align:start position:0% +fourth generation nuclear power I mean + + + align:start position:0% +fourth generation nuclear power I mean +that's you know that's an absolute core + + align:start position:0% +that's you know that's an absolute core + + + align:start position:0% +that's you know that's an absolute core +climate strategy in my view but I think + + align:start position:0% +climate strategy in my view but I think + + + align:start position:0% +climate strategy in my view but I think +it's increasingly widespread at MIT + + align:start position:0% +it's increasingly widespread at MIT + + + align:start position:0% +it's increasingly widespread at MIT +right and we're not staffing that + + align:start position:0% +right and we're not staffing that + + + align:start position:0% +right and we're not staffing that +revolution up in Romer's terms I'm not + + align:start position:0% +revolution up in Romer's terms I'm not + + + align:start position:0% +revolution up in Romer's terms I'm not +putting enough prospectors on the + + align:start position:0% +putting enough prospectors on the + + + align:start position:0% +putting enough prospectors on the +problem it's increasingly hard to + + align:start position:0% +problem it's increasingly hard to + + + align:start position:0% +problem it's increasingly hard to +organize startups that do something + + align:start position:0% +organize startups that do something + + + align:start position:0% +organize startups that do something +other than software in biotech because + + align:start position:0% +other than software in biotech because + + + align:start position:0% +other than software in biotech because +venture capital is just doing too well + + align:start position:0% +venture capital is just doing too well + + + align:start position:0% +venture capital is just doing too well +with those models and look there's + + align:start position:0% +with those models and look there's + + + align:start position:0% +with those models and look there's +nothing wrong with software in biotech + + align:start position:0% +nothing wrong with software in biotech + + + align:start position:0% +nothing wrong with software in biotech +it's you know it's important stuff so + + align:start position:0% +it's you know it's important stuff so + + + align:start position:0% +it's you know it's important stuff so +it's nothing wrong with what they're + + align:start position:0% +it's nothing wrong with what they're + + + align:start position:0% +it's nothing wrong with what they're +doing but we are not funding other + + align:start position:0% +doing but we are not funding other + + + align:start position:0% +doing but we are not funding other +technology sectors so we don't have a + + align:start position:0% +technology sectors so we don't have a + + + align:start position:0% +technology sectors so we don't have a +broad-based approach on technology + + align:start position:0% +broad-based approach on technology + + + align:start position:0% +broad-based approach on technology +advance so your metaphor Marteen of some + + align:start position:0% +advance so your metaphor Marteen of some + + + align:start position:0% +advance so your metaphor Marteen of some +empty kitchens we're emptying our + + align:start position:0% +empty kitchens we're emptying our + + + align:start position:0% +empty kitchens we're emptying our +kitchens on quote hard technologies + + align:start position:0% +kitchens on quote hard technologies + + + align:start position:0% +kitchens on quote hard technologies +where you'd have to manufacture + + align:start position:0% +where you'd have to manufacture + + + align:start position:0% +where you'd have to manufacture +something because the scale-up process + + align:start position:0% +something because the scale-up process + + + align:start position:0% +something because the scale-up process +is much harder for that financing system + + align:start position:0% +is much harder for that financing system + + + align:start position:0% +is much harder for that financing system +to muster then scaling up you know a + + align:start position:0% +to muster then scaling up you know a + + + align:start position:0% +to muster then scaling up you know a +software startup where it's + + align:start position:0% +software startup where it's + + + align:start position:0% +software startup where it's +infrastructures in the cloud and doesn't + + align:start position:0% +infrastructures in the cloud and doesn't + + + align:start position:0% +infrastructures in the cloud and doesn't +cost anything and can stale scale up + + align:start position:0% +cost anything and can stale scale up + + + align:start position:0% +cost anything and can stale scale up +very quickly with very limited amounts + + align:start position:0% +very quickly with very limited amounts + + + align:start position:0% +very quickly with very limited amounts +of capital it's much more complicated to + + align:start position:0% +of capital it's much more complicated to + + + align:start position:0% +of capital it's much more complicated to +stand up a new energy technology it's a + + align:start position:0% +stand up a new energy technology it's a + + + align:start position:0% +stand up a new energy technology it's a +longer term project than some more + + align:start position:0% +longer term project than some more + + + align:start position:0% +longer term project than some more +expensive scalar process so we're not + + align:start position:0% +expensive scalar process so we're not + + + align:start position:0% +expensive scalar process so we're not +doing those so we've got a gap and we'll + + align:start position:0% +doing those so we've got a gap and we'll + + + align:start position:0% +doing those so we've got a gap and we'll +talk about this in the next class in the + + align:start position:0% +talk about this in the next class in the + + + align:start position:0% +talk about this in the next class in the +innovation system that's yielding a + + align:start position:0% +innovation system that's yielding a + + + align:start position:0% +innovation system that's yielding a +bunch of empty kitchens around our + + align:start position:0% +bunch of empty kitchens around our + + + align:start position:0% +bunch of empty kitchens around our +economy whereas I'd argue what we want + + align:start position:0% +economy whereas I'd argue what we want + + + align:start position:0% +economy whereas I'd argue what we want +to do is fill those kitchens up but + + align:start position:0% +to do is fill those kitchens up but + + + align:start position:0% +to do is fill those kitchens up but +they've got to have a pathway to success + + align:start position:0% +they've got to have a pathway to success + + + align:start position:0% +they've got to have a pathway to success +as part of that that you follow me said + + align:start position:0% +as part of that that you follow me said + + + align:start position:0% +as part of that that you follow me said +add up is that what you're after Tara + + align:start position:0% + + + + align:start position:0% + +they're going up the kitchen set no + + align:start position:0% +they're going up the kitchen set no + + + align:start position:0% +they're going up the kitchen set no +one's going to right now right and look + + align:start position:0% +one's going to right now right and look + + + align:start position:0% +one's going to right now right and look +if we could get energy onto the wave + + align:start position:0% +if we could get energy onto the wave + + + align:start position:0% +if we could get energy onto the wave +right it would make all the difference + + align:start position:0% +right it would make all the difference + + + align:start position:0% +right it would make all the difference +we could do it right so if we could + + align:start position:0% +we could do it right so if we could + + + align:start position:0% +we could do it right so if we could +manage to get it into this phase and + + align:start position:0% +manage to get it into this phase and + + + align:start position:0% +manage to get it into this phase and +we're not we're strolling the build-up + + align:start position:0% +we're not we're strolling the build-up + + + align:start position:0% +we're not we're strolling the build-up +phase but if we could get here that gets + + align:start position:0% +phase but if we could get here that gets + + + align:start position:0% +phase but if we could get here that gets +to be really interesting yeah max I + + align:start position:0% +to be really interesting yeah max I + + + align:start position:0% +to be really interesting yeah max I +follow fusion a lot because MIT has been + + align:start position:0% +follow fusion a lot because MIT has been + + + align:start position:0% +follow fusion a lot because MIT has been +so involved in this so it's been one of + + align:start position:0% +so involved in this so it's been one of + + + align:start position:0% +so involved in this so it's been one of +my more fun adventures in recent years + + align:start position:0% +my more fun adventures in recent years + + + align:start position:0% +my more fun adventures in recent years +is working with your fusion team on some + + align:start position:0% +is working with your fusion team on some + + + align:start position:0% +is working with your fusion team on some +of these issues but you're right that + + align:start position:0% +of these issues but you're right that + + + align:start position:0% +of these issues but you're right that +technological advances that could + + align:start position:0% +technological advances that could + + + align:start position:0% +technological advances that could +actually scale this thing actually now I + + align:start position:0% +actually scale this thing actually now I + + + align:start position:0% +actually scale this thing actually now I +think for the first time is great + + align:start position:0% +think for the first time is great + + + align:start position:0% +think for the first time is great +concern to me exciting yeah you to find + + align:start position:0% +concern to me exciting yeah you to find + + + align:start position:0% +concern to me exciting yeah you to find +you you're right on a whole series of + + align:start position:0% +you you're right on a whole series of + + + align:start position:0% +you you're right on a whole series of +big important problems that we need to + + align:start position:0% +big important problems that we need to + + + align:start position:0% +big important problems that we need to +keep bringing into this class discussion + + align:start position:0% +keep bringing into this class discussion + + + align:start position:0% +keep bringing into this class discussion +and you know creating a culture around + + align:start position:0% +and you know creating a culture around + + + align:start position:0% +and you know creating a culture around +science and creating culture around + + align:start position:0% +science and creating culture around + + + align:start position:0% +science and creating culture around +technology development a culture around + + align:start position:0% +technology development a culture around + + + align:start position:0% +technology development a culture around +entrepreneurship and a culture around + + align:start position:0% +entrepreneurship and a culture around + + + align:start position:0% +entrepreneurship and a culture around +startups those turned out to be fairly + + align:start position:0% +startups those turned out to be fairly + + + align:start position:0% +startups those turned out to be fairly +key it's hard for economics that's + + align:start position:0% +key it's hard for economics that's + + + align:start position:0% +key it's hard for economics that's +trying to do mathematical modeling to + + align:start position:0% +trying to do mathematical modeling to + + + align:start position:0% +trying to do mathematical modeling to +capture these cultural historical issues + + align:start position:0% +capture these cultural historical issues + + + align:start position:0% +capture these cultural historical issues +but they're there and you know part of + + align:start position:0% +but they're there and you know part of + + + align:start position:0% +but they're there and you know part of +what makes innovation systems Theory so + + align:start position:0% +what makes innovation systems Theory so + + + align:start position:0% +what makes innovation systems Theory so +interesting is just the sheer complexity + + align:start position:0% +interesting is just the sheer complexity + + + align:start position:0% +interesting is just the sheer complexity +of that system and the number of + + align:start position:0% +of that system and the number of + + + align:start position:0% +of that system and the number of +variables operating there and you're + + align:start position:0% +variables operating there and you're + + + align:start position:0% +variables operating there and you're +right on an important point + + align:start position:0% + + + + align:start position:0% + +understanding the historical context for + + align:start position:0% +understanding the historical context for + + + align:start position:0% +understanding the historical context for +example turns out to be pretty key when + + align:start position:0% +example turns out to be pretty key when + + + align:start position:0% +example turns out to be pretty key when +you look at innovation systems in + + align:start position:0% +you look at innovation systems in + + + align:start position:0% +you look at innovation systems in +different regions of the world right + + align:start position:0% +different regions of the world right + + + align:start position:0% +different regions of the world right +different regions have different ways of + + align:start position:0% +different regions have different ways of + + + align:start position:0% +different regions have different ways of +organizing innovation systems the + + align:start position:0% +organizing innovation systems the + + + align:start position:0% +organizing innovation systems the +innovation system that got organized in + + align:start position:0% +innovation system that got organized in + + + align:start position:0% +innovation system that got organized in +Japan coming out of the second world war + + align:start position:0% +Japan coming out of the second world war + + + align:start position:0% +Japan coming out of the second world war +it's a very different innovation system + + align:start position:0% +it's a very different innovation system + + + align:start position:0% +it's a very different innovation system +than the u.s. organized and we'll try + + align:start position:0% +than the u.s. organized and we'll try + + + align:start position:0% +than the u.s. organized and we'll try +and talk about some of that actually in + + align:start position:0% +and talk about some of that actually in + + + align:start position:0% +and talk about some of that actually in +the next class but keep bringing us back + + align:start position:0% +the next class but keep bringing us back + + + align:start position:0% +the next class but keep bringing us back +to these two these cultural factors + + align:start position:0% +to these two these cultural factors + + + align:start position:0% +to these two these cultural factors +Thank You Martha you've got a question + + align:start position:0% + + + + align:start position:0% + +what have been useful right right right + + align:start position:0% +what have been useful right right right + + + align:start position:0% +what have been useful right right right +and there's you know I mean in a society + + align:start position:0% +and there's you know I mean in a society + + + align:start position:0% +and there's you know I mean in a society +there in the end there is no substitute + + align:start position:0% +there in the end there is no substitute + + + align:start position:0% +there in the end there is no substitute +for leadership right you really need a + + align:start position:0% +for leadership right you really need a + + + align:start position:0% +for leadership right you really need a +big dose of that as well and you know we + + align:start position:0% +big dose of that as well and you know we + + + align:start position:0% +big dose of that as well and you know we +will talk more about innovation systems + + align:start position:0% +will talk more about innovation systems + + + align:start position:0% +will talk more about innovation systems +and how can you nurture change agents + + align:start position:0% +and how can you nurture change agents + + + align:start position:0% +and how can you nurture change agents +particularly for innovation in these + + align:start position:0% +particularly for innovation in these + + + align:start position:0% +particularly for innovation in these +legacy established complex sectors like + + align:start position:0% +legacy established complex sectors like + + + align:start position:0% +legacy established complex sectors like +energy how can you introduce change + + align:start position:0% +energy how can you introduce change + + + align:start position:0% +energy how can you introduce change +agents and what tool sets can they use + + align:start position:0% +agents and what tool sets can they use + + + align:start position:0% +agents and what tool sets can they use +to actually drive change so we'll talk + + align:start position:0% +to actually drive change so we'll talk + + + align:start position:0% +to actually drive change so we'll talk +about that particularly in the energy + + align:start position:0% +about that particularly in the energy + + + align:start position:0% +about that particularly in the energy +class but it's relevant to many others + + align:start position:0% + + + + align:start position:0% + +you \ No newline at end of file diff --git a/RgScJ20EnW8.txt b/RgScJ20EnW8.txt new file mode 100644 index 0000000000000000000000000000000000000000..23ec601994954003fa5aa463cd69e15f2d46b0a9 --- /dev/null +++ b/RgScJ20EnW8.txt @@ -0,0 +1,3866 @@ +The following +content is provided + +under a Creative +Commons license. + +Your support will help MIT +OpenCourseWare continue + +to offer high-quality +educational resources for free. + +To make a donation, or to +view additional materials + +from hundreds of MIT courses, +visit MIT OpenCourseWare + +at ocw.mit.edu. + +PROFESSOR: OK, in that case, +let's begin in our usual way + +by going through a review +of last time's lecture. + +Last time, we talked +really about two + +calculational problems. + +One was the calculation of +the age of the universe, + +taking into account a +universe model which + +has matter, radiation, +vacuum energy, and curvature. + +And we got the general formula. + +And then for the same type +of cosmological model, + +we also calculated how +one finds the brightness + +of a distant source-- +the energy flux in terms + +of the redshift of that source. + +So first, the age of the +universe calculation-- + +that really just depends on the +first-order Friedman equation, + +which I've rewritten here. + +We put three terms +on the right hand + +side for the mass density-- a +matter term, a radiation term, + +and a vacuum energy term. + +And we know-- and this is +the important ingredient-- + +we know how each depend +on the scale factor. + +Non-relativistic +matter falls off like 1 + +over the cube of +the scale factor. + +Radiation falls off like +1 over the fourth power + +of the scale factor. + +And vacuum energy +is just constant. + +Next step that we did was just +to rewrite this equation, where + +we put in the explicit +time dependence + +in the form of this x +which is the ratio of a + +of t to the present value of +the scale factor-- a of t 0. + +And furthermore, we +expressed the matter density + +in terms of the present +contribution to omega. + +And rewriting equation in that +language, it takes that form. + +And then, I pulled a fast one. + +I said we could also +write this last term + +to look pretty much +like the others. + +It just is a constant that +falls off like 1 over a squared. + +So if you define +omega sub k 0, which + +is exactly what you need to +make this look like that, + +and in terms of omega +sub k 0, all four terms + +have the same characteristic. + +They're just a constant +times a power of x. + +So this is, then, the rewriting +of the Friedman equation one + +more time, just using this +new definition of how we're + +going to treat the +curvature of the universe. + +And simply by looking +at this formula + +and applying it +to x equals 1, you + +can see that that +becomes then 1 is + +equal to the sum +of these omegas. + +And that can be thought +of as a clearer, perhaps, + +definition of what +omega sub k 0 is. + +It's just 1 minus all of the +other contributions to omega. + +So it's how much the actual +mass density of the universe + +differs from the +critical density. + +Then once we have +this equation, which + +is the equation +which tells us what + +x dot is as a function of x, +we could just rewrite that + +by bringing dt to one +side of the equation + +and dx to the other and +integrating both sides. + +And that leads to +our final result. + +The age of the universe is +simply given by that integral. + +And this is a very +neat expression + +for the age of the +universe in terms + +of the present value of +the Hubble expansion rate + +and each contribution to omega +in terms of its present value. + +And you just plug those +into this formula. + +In general, you have to do +the integral numerically, + +because the integral's +a little too complicated + +to have an analytic expression. + +And that will give you +the age of universe + +for any model that +meets this description. + +So any questions about that +calculation before we go on? + +OK, very good. + +The next calculation +we did last time + +was the calculation of +radiation flux versus redshift. + +And this is exactly +what the astronomers + +were measuring in 1998 +when they concluded + +that the universe +was accelerating. + +They were looking at distant +supernova type 1a explosions. + +They made the assumption +that all supernova type + +1a explosions have the same +intrinsic power output. + +That's based roughly on +observation and guesswork. + +There's not really a +good theory for it, + +so it's mostly a matter of being +consistent with observations. + +But then they could +calculate for any given model + +in terms of these different +omegas what you expect in terms + +of received radiation as +a function of redshift. + +And they compared their +data with the models-- + +and I'll show you +that data shortly-- + +and found that the +models only fit + +if one had a significant +component of vacuum + +energy causing +universe to accelerate. + +So to do the calculation, we +need a metric for the universe. + +And I considered only +the closed universe case. + +There's also the flat +case and the open case, + +which are similar. + +And you'll actually be asked to +do those on the homework set. + +So the metric for +a closed universe + +can be written this +way, where sine psi is + +the square root of k +times r, to relate it + +to the other way-- the more +standard way-- of writing + +the Robertson Walker metric. + +But for our purposes +for this calculation, + +it's easiest to do it +this way, because we're + +going to be interested in +radio trajectories of photons. + +And this metric simplifies +the radial direction + +as much as it can be. + +It's just d psi squared. + +Oh, it's the +computer that froze. + +You never know with Windows. + +I think we're in business now. + +Back to where we were. + +We have the metric. + +Now what we want to do +is imagine a light source + +being received by a detector. + +And we put the light +source in the center + +of our coordinate system. + +We put the detector at some +distance corresponding to psi + +equals psi sub D, where psi is +our radial coordinate and psi + +sub D is the radial +coordinate of the detector. + +We imagine a whole sphere +with the same radius + +as the detector, +because we expect + +the source to be +spherically symmetric. + +And therefore, the light +emitted by the source + +will be uniformly +spread over that sphere. + +And that will allow us to +calculate how much of it + +will hit the detector. + +The fraction +hitting the detector + +will just be the area +of the detector divided + +by the area of the sphere. + +The area of the detector +is whatever it is. + +We call it capital A. +The area of the sphere + +is 4 pi times the +radius of the sphere. + +And the radius of the sphere +in physical coordinates + +is the scale factor squared +times the sine squared + +of psi sub D, coming +from the metric. + +It's the radius that appears +in the angular part that + +counts, because it's the angles +that we're integrating over + +to get the area of the sphere. + +So the radius is +just a tilde squared + +times sine squared is +the radius squared. + +Then we also need to +remember something + +we've said a number of times +previously in this class, which + +is that when the photons +travel from the source + +to the detector, their +intensity is suppressed + +by two powers of 1 plus z, +two powers of the redshift. + +And one of those +factors in 1 plus z + +comes from redshifting +each photon. + +The frequency of each +photon is redshifted, + +and that means that the energy +of each photon is redshifted-- + +goes down by a +factor of 1 plus z. + +But in addition, the rate +of arrival of the photons + +is essentially a clock +which is also time dilated. + +So the rate of arrival of the +photons as seen by the observer + +is suppressed by another +factor of 1 plus z. + +So putting all that together, +the received energy flux, + +which is the power received +divided by the area, + +is just the power emitted by +the source divided by 4 pi. + +We get this factor +of 1 plus z squared, + +due to what we just discussed. + +And then the a squared of +t sine squared psi sub D. + +So it's just the total +power times that fraction + +that we receive times the two +factors of 1 over 1 plus z. + +And this then is essentially +the final answer, + +except we want to know how to +evaluate a tilde squared of t 0 + +and sine squared of psi +sub D in terms of things + +that we more directly measure. + +So to do that, a +tilde of t 0 turns out + +to be easy, because +it really is just + +related by the definition of +omega sub k 0 to omega sub k 0. + +So this formula is +just a rewriting + +of the definition +of omega sub k 0. + +To figure out what +psi is, we want + +to integrate along +the line of sight + +to be able to figure +out the time of emission + +in terms of psi. + +And that time of +emission could then + +be related to the redshift, +because the redshift is just + +the ratio of the scale factors +between reception and emission. + +So we look first at the metric. + +And say we're +going to be looking + +at null geodesics in +the radial direction. + +And null means ds +squared equals 0, + +and that's minus c +squared dt squared + +plus a tilde squared of +t times d psi squared. + +And that implies +immediately that the psi dt + +is just equal to the speed +of light divided by a tilde. + +And then we can get +the total increment + +in psi between the source +and us by integrating + +between the time of +emission-- the time + +of the source-- to the +present time-- t sub 0. + +And then it's just a matter +of changing variables + +to express the variable +of integration. + +Instead of st, we could express +it as z-- the redshift itself. + +And that brings in a factor of +h, because h is a dot over a. + +And I showed the +manipulations last time, + +but it brings in a factor of h. + +But we know what h is +as a function of z. + +It comes from the +Friedman equation. + +And that then gives us an +expression for psi of z sub + +s as an integral over z. + +And writing in what h of +z is and what a tilde of z + +is from that expression, +the expression for psi of z + +becomes the equation +that's boxed. + +Just a matter of algebraic +substitutions involving + +the Friedman equation, which +determines what h of z is. + +And then putting +everything together, + +J is just given by this +expression, where all I've done + +is to substitute the +expression for a tilde of c 0. + +And sine squared +psi is still here, + +but it gets evaluated +according to that formula. + +And putting these together, +we have a complete calculation + +of the received radiation +flux as a function + +of cosmological parameters-- +the omegas and the h 0-- + +and the redshift of the source. + +And that's the end +of the calculation. + +And that's where we +finished last time. + +So any questions about +that calculation? + +OK, fine. + +In that case, moving on, the +next thing I wanted to show you + +was some real data. + +So here are some real data +from one of those two teams + +that made the original +announcements in 1998. + +This is from the High-Z +Supernova Search Team. + +And I should write some +definitions on the blackboard. + +The vertical axis there +is essentially brightness. + +But you wouldn't expect the +astronomers to just call + +it brightness, because they +like to use fancier words. + +So they write it as +little m minus capital + +M-- measured in magnitudes, +they put in parentheses. + +And little m minus +capital M has the name, + +it's called the +distance modulus, + +meaning it's a way of +measuring distance. + +They think of brightness as +a way of measuring distance, + +which indeed is what +it's being used for. + +And it's defined as +5 times the logarithm + +base 10 of d sub L +over 1 megaparsec, + +which means the luminosity +distance-- I'll define this + +in more detail in +a second-- d sub L + +is the luminosity distance-- +distance as inferred + +from the luminosity. + +And they're measuring +it in megaparsecs + +and taking the +logarithm base 10. + +And then, by convention, +there's an offset here of 25. + +Why not? + +So this is the definition +of the distance modulus. + +And d sub L is defined by +the relationship of what + +J would be in a flat +Euclidean universe + +if you were receiving +that luminosity. + +So J is equal to +the actual power + +output of the source divided +by 4 pi d sub L squared. + +This defines d sub L. So +d sub L is the distance + +that that source would have +to be at in a static Euclidean + +universe for you to see +it with the brightness + +that you actually see. + +This, I guess, completes +the definitions, + +but we can put these together. + +And m minus M is then +equal to minus 5/2 + +times the logarithm +base 10 of 4 pi J times + +1 megaparsec squared, +divided by the actual power + +output of the source, and +then, of course, plus 25. + +So this relates this +distance modulus + +to the energy flux and the power +output of the original source. + +There's also on this +slide the acronym MLCS. + +MLCS stand for multi-color +light curve shape. + +And what that refers to is the +High-Z Supernova Search Team + +invented a method of +compensating, to some extent, + +for small variations +in the actual power + +output of the +supernovae type 1a. + +Instead of assuming +that they all + +have exactly the +same brightness, + +they discovered by looking at +nearby supernovae of this type + +that there's a correlation +between the absolute brightness + +of the supernovae and the +shape of the light curve-- + +that is, light versus time. + +So they were careful to +measure the light versus time + +for the supernovae that +they used in this study. + +And they used that as a way +of applying a small correction + +to what they interpreted +as the intrinsic brightness + +of each supernova. + +And the results +are these points. + +[INAUDIBLE] the top +are the raw points, + +and three different curves +for three different models. + +And they characterize the +models in the same way + +we would-- in terms of different +contributions to omega. + +So the top model is the +cosmological constant dominated + +model, where omega +sub lambda, which + +is what we've been calling +omega sub vac is 0.76. + +And it's a flat model, +so 0.24 for omega matter. + +And radiation is ignorable. + +They compared that with the +middle model of these three, + +which was a model that +had no vacuum energy, + +and omega matter of 0.2. + +That was essentially +the dominant model + +at the time, the belief that +the universe was open then + +had about a critical +density of 1/5 or 1/4. + +And then they also +compared it with a model + +where omega was 1-- entirely of +matter with no vacuum energy. + +And that was this +dashed curve, which + +is the lower of +these three curves. + +And when the data +is just plotted, + +it's a little hard to see +how much difference there + +is between the three curves. + +So they re-plotted the data, +plotting the middle curve + +as a straight line +by construction. + +And then they plotted +deviations from that line. + +And they did that for both +the theoretical curves + +and the data. + +And in this magnified +picture, you + +can see a little bit better +that this top curve fits + +things the best. + +And that's what they call +the lambda CDM model. + +It corresponds to +omega m equals 0.24. + +Omega lambda equals 0.76. + +So it's the model with +a cosmological constant, + +with a vacuum energy. + +And lambda CDM stands for +lambda and cold, dark matter. + +And cold, dark +matter is just what + +we've been calling +non-relativistic matter. + +So the claim is that these data +points, even though there's + +a fair amount of scatter, +fit the top curve much, + +much better than they +fit the middle curve + +or the bottom curve. + +And statistically, that's true. + +It really is a much better +fit, even though by eye, it's + +not that clear what's going on. + +I think by eye it looks clear +that the top one fits it better + +than others, but +it's not that clear + +how important the difference is. + +But nonetheless, the astronomers +were thoroughly convinced + +that this was a real effect. + +There was considerable +discussion + +about possible +systematic errors. + +And I guess next, I'll say +a few words about that. + +First of all, I +should maybe just + +clarify a little bit +better what's being seen. + +What's being seen is that for +a given redshift, this curve, + +which basically shows brightness +in a funny, funny way, where + +dimmer is upward, larger +values of little m minus M-- + +there's a minus sign +in this formula-- + +means a dimmer galaxy, one +that looks further away. + +And basically, when astronomers +see this, they think distance. + +So larger values +means further away. + +So what's being seen is that +these distant supernovae + +are a little bit +dimmer than what + +you would expect in either +of the other two models, + +either of the models that +do not have vacuum energy. + +And the amount by +which they're dimmer + +is a few tenths of a magnitude. + +And each tenth of a magnitude +corresponds to about 10% + +in brightness. + +So what they're saying is that +these distant if supernovae, + +if we assume they +really fit this curve, + +are 20% to 30% +dimmer than you would + +have expected in other models. + +It might be worth saying a +little bit about why dimmer + +is the right sign to correspond +to acceleration, which + +is by no means totally +obvious, I don't think. + +So we're plotting-- + +AUDIENCE: What year is this? + +PROFESSOR: What year? + +This was old data that +was published in 1998. + +It has gotten better. + +Now it's much more +unambiguous that this works. + +So this is distance as +inferred by brightness. + +So this is basically +what's being plotted. + +If one thinks about a +fixed z in which way + +that you go-- up or down-- +I find that totally cryptic. + +I don't really parse that +very well in my own head. + +But it's much clearer if you +think about the other way. + +You could think about a +galaxy-- or a supernova + +in this case-- at a +fixed distance, and ask, + +suppose I compare different +models-- ones that accelerate + +and models that +don't accelerate. + +So if we fix the distance +and say, what would we + +expect for the +redshift of a given + +galaxy, in an accelerating +model versus a non-accelerating + +model-- remember, the +redshift is basically + +a measure of the +velocity, or at least it's + +strongly influenced by the +velocity of the object. + +So if the universe +is accelerating, + +it means that the universe was +expanding slower in the past + +than you would have +thought otherwise. + +It's speeded up to reach +its present expansion rate. + +So an accelerating +universe is a universe + +that was expanding +slower in the past. + +And slower in the past means +that a galaxy at a given + +distance would have +been moving slower, + +and hence would have +had a lower value of z. + +So the effect of acceleration +for a given distance-- we'll + +fix the distance-- should be +to move the line that way, + +towards lower z. + +And by moving the dot that way, +it puts it above the curve. + +So it's the same as +shifting things up, + +which is the more +natural way of describing + +what's seen in the graph. + +The points are higher +than the curve. + +So the bottom line, though, +is that what they're saying + +is distant supernovae are +20%, 30% dimmer than you + +might have thought. + +And from that, they want to +infer that the universe is + +accelerating, which is a +rather dramatic conclusion. + +So naturally, you +want to ask, are there + +other things that can cause +supernovae to look dimmer? + +And of course, there +are other things + +that can cause +supernovae to look dimmer + +than you might have thought. + +And there are two +main ideas that + +were discussed at the time. + +One of them is just plain dust. + +If you're looking at something +through a dusty atmosphere, + +it looks dimmer than +it would otherwise. + +And that is a +genuine possibility + +that was strongly considered. + +The arguments against +dust were mainly twofold. + +The first is that +dust very rarely + +absorbs uniformly +across the spectrum. + +Dust usually-- depending on +the size of the dust grains-- + +absorbs more blue +light than red light, + +leaving more red +light coming through. + +So the effect of seeing +something through dust + +is normally to cause +it to look more red. + +And this reddening was not seen. + +The spectrum of the light +from the existing supernovae + +was analyzed very carefully. + +And the spectrum +of the distant ones + +looked just like the spectrum of +the nearby ones-- appropriately + +redshifted, of course, but +otherwise not distorted + +in any way. + +There was no sign +of this reddening. + +Now, it's possible to have +what the astronomers refer + +to as gray dust, which is by +definition dust that absorbs + +uniformly across the spectrum +of what you're looking at. + +But the grains have +to be unusually large. + +And nobody was ever +able to figure out + +a source for dust +grains of that sort. + +So based partly on +theoretical grounds + +and partly on what +nobody has ever found, + +there's no evidence +for dust grains + +that would possibly +cause dimming + +that would look this way, +that would be dimming + +that was uniform +across the spectrum. + +Yes? + +AUDIENCE: How do you +tell the difference + +between reddened light from +dust and redshifted light? + +PROFESSOR: OK, how do +you tell the difference + +between reddened light from +dust and plain old redshift? + +The difference is that the +plain old redshift uniformly + +shifts everything +by the same factor. + +So the whole spectrum is +just moved down uniformly + +towards the red. + +This reddening +effect really means + +that the blue part +of the spectrum + +is depressed relative +to the red part. + +So the shape of the +spectrum is changed. + +So one argument is that +we don't see reddening, + +and we don't know any way to +make dust that would be gray. + +The second argument is that +if dust was a major factor, + +presumably most of the +dust that would be relevant + +would be dust in the same galaxy +as the supernova explosion + +itself, because there's +not that much dust + +in intergalactic space. + +And if dust in the galaxy of the +supernova itself were relevant, + +then-- let me draw a +little picture here. + +So if dust in what's +called the host + +galaxy-- the galaxy which +has the supernova in it-- + +then you would have +a picture where + +there would be a ball of +dust filling the galaxy. + +And the supernova that you're +looking at might be there, + +or it might be there. + +And let's say we're +looking from over here. + +So depending on where the +supernova was in the galaxy, + +we would see very different +amounts of intervening dust. + +And if dust were +causing this dimming, + +it would mean we would be +seeing a significant scatter + +in the amount of dimming +depending on where + +the supernova happened +to be in its host galaxy. + +And that spread was not seen. + +The spread that one +sees in that curve + +could be measured and calibrated +against known uncertainties + +in the brightness of +supernovae and then + +the detection apparatus. + +And the spread that +was seen was just what + +you expect without any +additional spread associated + +with a dusty galaxy +acting as the host. + +So no evidence for the +spread of brightnesses + +that would be expected +from a dusty host. + +Another item that +was considered-- + +these are the main +arguments against dust-- + +another argument +that was considered, + +another possible source of +dimming, is galactic evolution. + +And there, the main effect +that people worried about + +was the production of +heavy chemical elements + +during the life of a galaxy. + +As you've certainly learned +about from your reading-- + +I don't know if we've talked +about it in class or not-- + +the early universe was essential +all hydrogen and helium. + +Heavier elements were +made later in stars + +that produce +supernovae explosions. + +And these supernovae +explosions gradually + +cause galaxies to become +more and more enriched + +with heavy elements. + +And by heavy, I mean +anything heavier than helium. + +And that could +affect, in principle, + +the behavior of +supernovae explosions. + +So the evidence +against that was simply + +that every other +characteristic that astronomers + +could measure of +these supernovae + +in the distant +galaxies looked exactly + +like what was seen +for nearby galaxies. + +So no evidence for any +kind of evolution was seen. + +And there are many +properties you + +could measure that are +independent of distance, + +like the shape of the +spectrum and things like that, + +and the pattern of the +light curve versus time. + +So all those characteristics +that astronomers can measure + +seem to be exactly the same +for the very distant supernovae + +which happened +billions of years ago, + +and the more nearby ones +that happened recently. + +And furthermore, +among the nearby ones, + +there's a big spread of +abundances of heavy chemical + +elements, just because +different galaxies + +have had different histories. + +So among the nearby +ones, you could + +look for is there +an effect caused + +by the relative abundance +of heavy elements, + +and astronomers didn't find any. + +So there was no sign +that galactic evolution + +could be playing a role +here, even though one + +does need to worry about it. + +So the point is that +distant supernovae 1a + +look like nearby ones. + +I'll call that a in my outline. + +And b is that among the nearby +1a's, heavy element abundance + +had no perceptible effect. + +So the dominant opinion +gradually shifted, + +and now I think it's almost 100% +that this acceleration is real. + +The acceleration, by +the way, is further + +confirmed by measurements +of fluctuations + +in the cosmic background +radiation measurements that + +have been done by some +ground-based experiments, + +and also the satellite +experiments of WMAP + +and now Planck, which +measure the anisotropies-- + +the ripples-- in the cosmic +background radiation. + +It's hard to see what +those ripples would + +have to do with the +amount of vacuum energy. + +But it does turn out-- and +we'll talk more about this + +a little bit later-- +that we really + +do have a detailed theory +of what makes these ripples. + +We can calculate what the +spectrum of those ripples + +should look like. + +And the calculations +depend on parameters + +which include the +amount of vacuum energy. + +And in order to +make things work, + +one does have to put +in essentially exactly + +the same amount of vacuum +energy as has been detected + +in these supernova +1a observations. + +So everything fits +together very tightly. + +And I think now, just about +everybody is convinced + +that the universe +really is accelerating. + +The acceleration +could, in principle, + +have at least two different +causes that we can talk about. + +One is vacuum energy, which is +the one that I'm focusing on, + +which is the +simplest explanation. + +The other possibility that is +discussed in the literature + +is something called +quintessence, + +which is a made-up word. + +And what it refers +to is the possibility + +that the acceleration +of the universe today + +could be caused by a mechanism +which is really in principle + +exactly the same as what +we talk about for inflation + +in the early universe and +will be talking about later. + +Specifically, there could be +a slowly evolving scalar field + +which is essentially uniform +throughout the universe, + +and changing slowly with time so +it looks like it's a constant. + +And it could be the energy +density of that scalar field + +that is looking to us as +if it were vacuum energy. + +But that's the +minority point of view. + +And that introduces +extra parameters + +that don't seem to be necessary. + +But it's up for grabs. + +Nobody really knows. + +OK, any questions about +what we just talked about? + +In that case, let me go +on to my next topic, which + +is I want to talk +a little bit more + +about the physics +of vacuum energy. + +What is it that we +understand about it, + +and why is it that +most physicists say + +it's the least understood +issue in physics? + +We really don't +understand vacuum energy, + +even though we do understand +why it might be nonzero. + +Where we're totally at a loss +is trying to make any sense out + +of the value of the energy +density that is actually + +observed. + +So where does vacuum energy come +from in a quantum field theory? + +There are basically, I would +say, three contributions. + +Maybe I should say in +quantum field theory. + +The other context in which +this might be discussed + +would be string theory. + +I may or may not say +something about string theory, + +but I won't say much. + +But in quantum field +theory, there are basically, + +I think, three contributions. + +The first is the +easiest to understand, + +which is quantum fluctuations +in bosonic fields, + +where the best +example is the photon, + +or the electromagnetic field. + +Now, in a classical +vacuum, e and b-- the + +the electric and +magnetic fields-- + +would just be 0, because that's +the lowest possible energy + +density. + +But just as you are +probably aware that + +there's an uncertainty principle +in quantum mechanics which + +tells you that the momentum and +position of a particle cannot + +be well-defined +at the same time, + +it is also true that e and +b cannot be well-defined + +at the same time. + +So the uncertainty principles +applied to the field theory + +imply that e and b cannot +just be 0 and stay 0. + +E and b are constantly +fluctuating. + +And that means +that there's energy + +associated with +those fluctuations. + +And the mathematics of it is +actually incredibly simple. + +If one imagines the +fields inside a box, + +to be able to at least +avoid the infinity of space, + +the fields inside a +box could be described + +in terms of standing waves, +where each standing wave is + +either a half wavelength or +a full wavelength across. + +And by the way, you'll be doing +a homework problem on this. + +And each standing +wave has the physics + +of a harmonic oscillator. + +It oscillates sinusoidally +with time, the wave. + +And when one works out +the mathematics, and even + +the quantum mechanics, +it's exactly the same + +as a harmonic oscillator. + +So each standing wave +has a zero-point energy. + +You may know that the zero-point +energy of a harmonic oscillator + +is not 0, but it's 1/2 h +bar omega, or 1/2 h nu, + +depending on whether you're +using nu or omega to describe + +the frequency of the oscillator. + +So each standing wave +contributes 1/2 h bar omega. + +And then the problem is how +many standing waves are there? + +And the answer is, there's +an infinite number of them, + +because there's no limit to how +short the wavelength can be. + +So there's no limit to +how many ups and downs you + +can have in your +standing wave from one + +end of the box to the next. + +So the answer you +get is infinite. + +It diverges. + +Now, the fact that it +diverges at short distances + +can be used as an excuse for +getting the problem wrong. + +Obviously, it's wrong. + +The answer's not infinite. + +But we have an excuse, +because we certainly + +know there are wavelengths +that are short enough + +that we don't understand the +physics at those length scales + +anymore. + +We're basing everything on +extrapolating from wavelengths + +that we can actually +measure in the laboratory. + +So one could +imagine that there's + +some wavelength beyond which +everything we're saying here + +is nonsense, and we don't have +to keep adding up 1/2 h bar + +omega anymore, +because the arguments + +that justify the 1/2 h +bar omega no longer apply. + +So we can use that as a +cutoff for the calculation. + +And a typical +cutoff-- by typical, I + +mean typical in arguments +that physicists talk about, so + +typical in physics speak. + +So a cutoff that's +often invoked here + +is the Planck scale, +which is the square root + +of h bar times G +divided by c cubed. + +And that has units +of length, and it's + +equal to about 1.6 times 10 +to the minus 33 centimeters. + +And what makes the +scale significant + +is it's the scale at which we +expect the effects of quantum + +gravity to start +to be important. + +And we know that +this quantum field + +theory that we're +talking about does not + +include the effects of gravity. + +And we don't really +even know how + +to modify it so that it would +include the effects of gravity. + +So the quantum +effects of gravity + +are still something +of a mystery. + +So it makes sense to +cut the theory off, + +if not earlier, at least +at the Planck scale. + +Yes? + +AUDIENCE: So I would imagine +what we're doing, in order + +to say that we have a standing +wave, we have to have a box. + +And then in order to realize +the fact that the universe may + +be large, you just take the +limit as the box gets large. + +But is it really OK to do that? + +I mean, to treat +an infinite system + +as the limit of a finite system? + +PROFESSOR: OK, the +question is-- what + +we're going to be +doing here is I + +talked about putting the +standing waves in a box. + +And then at the end, we're +going to take the limit + +as the box gets +bigger and bigger. + +And the question is, is +that really a valid way + +of treating the infinite space? + +And the answer is, +in this case, it is. + +I'm not sure how solid +an argument I can make. + +Certainly what one does +find is what you'd expect, + +that as you make the +box bigger and bigger, + +the energy that you get is +proportional to the size + +of the box. + +So you're calculating +an energy density. + +And probably the most precise +thing I can say at the moment + +is that if it were not true, +if the answer you got really + +depended on the way in which +the space was infinite, + +then you'd be learning something +about the infinite universe + +by doing an experiment +in the lab, which + +is a little far-fetched. + +That is, if you do an +experiment in a lab, + +it really doesn't +tell you anything + +about whether the universe +is infinite or turns back + +on itself and is closed. + +And calculations +certainly do show + +that you get the +same-- you could do, + +for example, a closed +universe without a box. + +And you get the +same energy density, + +as long as the universe was +big, as we're getting this way. + +So I think there's a pretty +solid calculational evidence + +that what you get does +not depend on the box. + +Yes? + +AUDIENCE: Going +off that question, + +do we use the maximum +size of our box + +as the size of our +observable universe, then? + +PROFESSOR: OK, the +question is, what do we + +use as the maximum +size of the box? + +Is it the size of the +observable universe? + +The answer really is +that what you find + +is that you get an energy +density that's independent + +of the size of the box, +as long as the box is big. + +And it's that energy density +that we're looking for. + +We don't claim to know anything +about the total energy. + +And we don't really +need to know anything + +about the total energy. + +Everything that we formulated +here in terms of energy + +densities. + +Now, the catch is, that +if one puts in this cutoff + +and takes into account only +the energies of 1/2 h bar + +omega going up to this cutoff +and stopping there-- or down + +to the cutoff if one's thinking +of length as the measure-- + +you could then ask, do +we get an energy density + +that's in any way close to +what the astronomers tell us + +the vacuum energy actually is? + +And the answer is +emphatically no. + +We don't get anything close. + +We're in fact off by about +120 orders of magnitude, + +which even in cosmology is +a significant embarrassment, + +which is why physicists consider +this question of the vacuum + +energy density to be such +an incredible mystery. + +We really have no +idea how to get + +a number as small +as what we observe. + +Let us go on to talk +about other contributions, + +because they are certainly +important in the way we + +think about things. + +So far I have number one, right? + +So next comes two. + +And that is the quantum +fluctuations of Fermi fields, + +where the best-known example +here is the electron. + +Now, in quantum field +theory, I should point out + +that all particles are described +by fields, not just the photon. + +The electron is described +by a field also. + +It's called the electron field. + +And because the electron is +a fermion and not a boson, + +the electron field has +somewhat different properties + +than bosonic fields, +reflecting the fact + +that the fermions themselves +obey the exclusion principle. + +It turns out that +for fermions, there + +are also quantum fluctuations. + +They're also of order +1/2 h bar omega. + +But actually, it's a +little bit different. + +They're in some sense h +bar omega and not 1/2. + +But what's peculiar is that +for electrons, the contribution + +is negative. + +And the origin of this +negativity I think + +has a fairly simple +explanations, + +although the explanation is +not ever given, actually. + +The exploration that's used +in quantum field theory books + +involves looking at +equation 47 and seeing + +that there's an +anticommutator there. + +And because the +fields anticommute, + +there's a minus sign. + +And that means the +energy is negative. + +And that is basically the way +it's described in textbooks. + +That certainly says +where the minus sign + +appears in which equation. + +But I don't think it's +really an explanation of what + +the minus sign is talking about. + +But I think there is an +explanation of what the minus + +sign is talking about, which +goes back to the old picture + +that Dirac himself +introduced when he first + +invented the Dirac equation. + +When Dirac first invented +the Dirac equation, + +he was trying to +interpret it more or less + +in the same language as +the Schrodinger equation. + +We don't quite do that anymore. + +But in doing that, +Dirac discovered + +that his Dirac +equation, which was + +the natural relativistic +generalization + +of the Schrodinger equation +to a particle which + +has spin 1/2, which I'm not sure +how Dirac knew it had spin 1/2, + +but in any case, +it's the equation + +for a particle of spin 1/2. + +And what he found was that if +you just look at the energy + +the spectrum that the +equation itself gives you, + +it's symmetric about 0. + +So if we plot energy going this +way, if there's a state here, + +there's also a state +there at negative energy. + +And if there's a +state there, there's + +another state there, +exactly opposite it. + +It's completely +symmetric up and down. + +Now, the interpretation +that Dirac gave to that + +was not that there are a lot of +ways of making negative energy. + +He realized that the +vacuum is by definition + +the state of lowest +possible energy. + +And if you can lower the +energy by adding a particle + +to these negative +energy states, that + +would mean that there'd be a +way of lowering the energy, + +and the state would +not be the vacuum. + +So the vacuum, Dirac +proposed, is the state + +in which all of these negative +energy levels are filled. + +And the action of putting +all these x's on the picture + +is often called +filling the Dirac sea. + +S-E-A-- sea, where sea refers +to this ocean of negative energy + +states, which is infinite. + +It just keeps going down. + +You can imagine filling all of +them to describe the vacuum. + +Then if you ask what is +the physics after you've + +done that-- what are +the possible excitations + +of the vacuum, what +states does this theory + +contain other than the vacuum? + +And the answer is that +there could be occupations + +of these positive energy states, +and those are called electrons. + +It's also possible +to remove-- if you + +put in the right +amount of energy-- + +one of the negative energy +states, which is filled, + +but we could take away +the particle that's there. + +And the absence of a +particle there-- a hole + +in the negative energy +sea-- is a positron. + +So electrons are there. + +The e plus is a hole +in the Dirac sea. + +Now, the difficulty +with this picture, + +and the reason why it's +not often use these days, + +is that it makes it +look like there's + +an intrinsic difference between +electrons and positrons. + +Nonetheless, Dirac +was perfectly aware + +that when you went +through the math, + +they were completely symmetric. + +The fact that you +described it this way + +is just really a feature +of your description, + +but it doesn't make any +measurable difference. + +So a positron really is just a +perfect image of an electron, + +but with the opposite +charge, with otherwise + +all the same +physical properties. + +And there's ways +of describing it + +where you don't make this +distinction between particles + +and holes. + +But the particle hole way +is I think the easiest + +way of understanding where the +negative energy is coming from. + +The negative energy came by +saying that the energy was 0 + +before we filled +any of these levels. + +And as you fill the +negative energy sea, + +you're lowering +energy all the time. + +And it's that contribution +which makes up + +the infinite negative +contribution coming + +from the Fermi fields. + +And the algebra is +certainly exactly right. + +The energy that +people write down + +for the negative energy +of the Fermi fields-- + +what they get by anticommuting +two operators in equation 37-- + +is exactly the +expression you get + +for what it takes to +fill the Dirac sea. + +Yes? + +AUDIENCE: Are we +pretty confident + +that the smallness +of the vacuum energy + +can't come from cancellations +between the bosonic + +and the Fermi fields? + +PROFESSOR: OK, the question +is, are we confident that + +the cancellation cannot come +from the cancellations between + +the Fermi fields and +the bosonic fields. + +No, we're all confident that +it cannot come from that. + +it very likely does +come from that. + +But we are confident that we +have no idea why that happens. + +And therefore, +it's a big mystery. + +Certainly our ignorance +allows for any answer. + +Because we have a positive +infinite contribution, + +we're just going to cut +off and make it large. + +And we're going to have a +negative contribution, which + +we're going to cut off and +make it large in magnitude + +but negative. + +And then we're +going to add them, + +and we have no idea +what we're going to get. + +But the fact that +we get something + +that gets incredibly close to +0, and not something that's + +at all the same magnitude as the +pieces you're adding together-- + +the positive piece or +the negative piece-- + +means there's something going +on that we don't understand. + +There's a cancellation that's +happening that we cannot + +explain. + +Now, I should maybe +add that there's + +one context where we would +expect a cancellation. + +And that is, there +are theories that + +are what are called +supersymmetric, + +which have a perfect symmetry +between bosons and fermions, + +which would relate the +positive energy from the photon + +to the infinite negative energy +you would get from particles + +called photinos, which would +be the supersymmetric partner + +of the photons-- a +spin 1/2 particle + +that's a mirror +image of a photon + +but has a fermionic character. + +So in an exactly +supersymmetric theory, + +you would get an +exact cancellation + +between the positive and +the negative contributions. + +And the answer has to be 0 in an +exactly supersymmetric theory. + +However, the world is clearly +not exactly supersymmetric. + +This photino has +never been seen. + +And there'd be a particle +called the selectron, which + +would be the scalar partner +of the electron, which + +also has not been seen. + +And every known +particle would have + +a partner, which +has not been seen. + +There are no supersymmetric +pairs which are known. + +So supersymmetry is +still a possibility + +as a broken symmetry of nature. + +And a lot of people think-- for +pretty good reasons, I thin-- + +that it's very likely +that the world does + +have an underlying +supersymmetry. + +But as long as the +supersymmetry is broken, + +it no longer guarantees +this cancellation. + +And you could estimate +what the mismatch is. + +And it does make things +a little bit better here. + +If we just take this +Planck scale cutoff, + +we miss an energy density by a +factor of about 10 to the 120. + +If we apply +supersymmetry and make + +an estimate of what the +supersymmetry breaking scale is + +and what effect that has on the +mismatch of these calculations, + +then it gets reduced. + +Instead of being 120 order +of magnitude problems, + +it's got a 50 order of +magnitude problem, which + +is a lot better, +but not good enough. + +Now, I do want to mention +a third contribution here + +for completeness. + +The third one is +likely be finite, + +so it's not as problematic +as the other two. + +AUDIENCE: [INAUDIBLE] + +PROFESSOR: Same thing. + +Planck scale. + +AUDIENCE: Oh, OK. + +PROFESSOR: The +third contribution + +is that some fields +are believed to have + +nonzero values in the vacuum. + +And the famous example of +that is the Higgs field, + +for which the particle +associated with the Higgs + +was discovered a +year ago at CERN, + +after over 50 years +of looking for it. + +And the Higgs field is +maybe the only field + +that's part of the +standard model that + +has a nonzero expectation value, +a nonzero value in the vacuum. + +But in more +sophisticated theories + +like grand unified +theories, there + +are many more fields that have +nonzero values in the vacuum. + +So that's a likely extension +of our standard model + +of particle physics. + +So the bottom line is that it's +easy for particle physicists + +to understand why the vacuum +energy should be nonzero, + +but damned hard to have any +idea of why it has the value + +that it has. + +We'll talk maybe at +the end of the course + +about the possibility that +the value of the vacuum energy + +density is, quote, +"anthropically selected." + +That is one possible +explanation, + +which maybe shows how +desperate physicists + +are to look for an +explanation here. + +One possible explanation +begins with ideas + +from string theory, where +string theory tells us + +that there isn't just +one kind of vacuum, + +but in fact, a huge number +of different types of vacuum, + +perhaps 10 to the 500. + +And that would +mean that if there + +were sort of random values for +these infinite numbers that + +get cut off, that get cut +off with different values-- + +and there are other ways +of looking at the vacuum + +energy in string +theories-- you'd + +expect coming out +of string theory + +that the typical vacuum energy +would be about the same as what + +you get when you +cut off the quantum + +fluctuations of the +electromagnetic field + +at the Planck scale. + +That is, the typical +vacuum energy coming out + +of a string theory would be +at the Planck scale, which + +is this huge number +compared to what we observe. + +But string theory +would be predict + +that there would be a spread +of numbers going essentially + +from plus the Planck scale +to minus the Planck scale, + +with everything in between. + +There'd be a tiny fraction +of those vacua that + +would have a very small vacuum +energy like what we observe. + +That's what you'd expect +from string theory-- + +a large number, but a tiny +fraction of vacua that + +would be in that integral. + +And then the only +problem would be + +to explain why we might likely +be living in such an unusually + +small fraction of the set +of all possible vacuums. + +And the answer to +that that's discussed + +is that it may be +anthropically selected. + +That is, life may only +form when the vacuum + +energy is incredibly small. + +And that is not built +entirely from whole cloth. + +There is some +physics behind that. + +We know that this vacuum energy +affects the Friedman equation, + +which means it affects the +expansion rate of the universe. + +So if we had a Planck +scale vacuum energy, + +that would cause the +universe to essentially blow + +apart at the time scale of the +Planck scale, which is about 10 + +to the minus 40 +something seconds, + +due to the huge repulsion +that would be created + +by that positive vacuum energy. + +And conversely, if there +was a huge negative vacuum + +energy on the order +of the Planck scale, + +the universe would just +implode on a time scale + +of order of the +Planck scale-- 10 + +to the minus 40 +something seconds. + +So assuming that life takes +billions of years to evolve + +and assuming nothing +else about life, + +one can conclude that +life can only exist + +in the very narrow band +of possible vacuum energy + +densities which are +incredibly small, like the one + +that we're living in. + +So it could be that we're +here only because there + +isn't any life anyplace else. + +So all living things see a very, +very small value of this vacuum + +energy density, even though +if you plunk yourself down + +at a random place +in this multiverse, + +you'd be likely to see +a vacuum energy that's + +near the Planck scale. + +OK, I'm done talking +about this for now. + +Any further questions about +it before we leave the topic? + +I had suggested that we go +on to talk about problems + +with the conventional +big bang model, + +but, there is actually +something else I wanted to do. + +I don't know how long +it will take exactly, + +but I have a little historical +interlude to talk about here. + +We've been talking about +the Friedman equations + +and how they're modified by the +cosmological constant, which + +of course is an item that was +very dear to Einstein's heart. + +So I'd like to tell +you a little history + +story about Albert Einstein +and Alexander Friedman, + +which I think is +very interesting. + +The punchline of the story is +that Einstein made pretty much + +of a fool out of +himself on this. + +And the reason why I like +the story is maybe twofold. + +One is, I find it +very comforting + +to know that even perhaps the +greatest physicist of all time + +can make dumb mistakes +just like the rest of us + +make dumb mistakes. + +I think that's a very comforting +thing to keep in mind. + +And the other moral +of the story is, + +I think, the +importance of trying + +to be open-minded about +issues in physics. + +Einstein was very much convinced +that the universe was static, + +and so convinced that, +in fact, he really made + +stupid mistakes trying to +defend his static universe. + +So this will be a story +of such a mistake. + +So those are the two people. + +Friedman was a Russian natural-- +he was really a meteorologist. + +They didn't really have that +many theoretical physicists + +back in those days. + +But as a meteorologist, +he was an expert + +in solving partial +differential equations, + +and got himself interested +in general relativity, which + +was a new theory at this point. + +And in 1922, he published +an actual physics paper, + +I think the first physics +paper he ever published, + +and one of two. + +He wrote basically two papers +about the Friedman equations-- + +one for closed universes, +and one for open universes. + +So the first of those +papers was published + +in June 29, 1922 in the premier +physics journal of the day-- + +the Zeitschrift fur +Physik, a German journal. + +And almost immediately-- +or a few months later, + +when Einstein noticed +this article-- + +Einstein submitted a comment +about the article claiming + +that the article was +entirely wrong, just + +mathematically wrong. + +And the article was titled +"Remark on the Work of A. + +Friedmann 'On the Curvature +of Space' " by A. Einstein, + +Berlin, received +September 18, 1922. + +Looking at these dates-- +the original article + +was received in June +1922, and Einstein + +was responding by September +18, a few months later. + +And this is a translation, +which comes from a book called + +Cosmological Constants, +which is basically + +a book of famous +articles in cosmology, + +like Friedman's, and all +these original articles. + +It's a great book if you +can still get a copy of it. + +It's no doubt out of print. + +It was written by Jeremy +Bernstein and Gary Feinberg. + +And I'm taking the +translation from there, + +because this was +written in German. + +I don't know German. + +"The works cited contains +a result concerning + +a non-stationary world +which seems suspect to me. + +Indeed, those +solutions do not appear + +compatible with the +field equations." + +And I guess A is the label +of the field equations + +as they appeared in +Friedman's paper. + +"From the field equation, +it follows necessarily + +that the divergence of the +matter tensor Tik vanishes." + +That is, energy +momentum is conserved + +as a four-vector quantity. + +"This along with ansatzes C and +D"-- equations from the paper-- + +leads, according to Einstein, +to an equation which we can all + +recognize the meaning of-- the +partial of rho with respect + +to x sub 4-- time-- is 0. + +Einstein convinced himself +that the equations of general + +relativity led to the conclusion +that rho cannot change with + +time. + +And he then goes on to +say "which together with 8 + +implies that the world radius +R"-- that's the scale factor. + +That's what we call a of +t-- "is constant in time. + +The significance of +the work, therefore, + +is to demonstrate +this constancy." + +All Friedman does +once you correct + +his equations, +according to Einstein, + +was prove that the only +cosmological solution is rho + +equals a constant, which was +Einstein's static solution. + +This was entirely wrong-- no +basis whatever in mathematics. + +But it took a while +before Einstein + +got himself straightened out. + +And he did actually +publish this. + +The sequence of events was, June +29, Friedman submits his paper. + +September 18, Einstein submits +his rebuttal to the paper. + +Friedman didn't learn about this +until the following December. + +Friedman had a friend who played +a key role in this story-- Yrui + +Krutkov, who was visiting +in Berlin during this time. + +And Friedman actually +learned from Krutkov + +that Einstein had +submitted a rebuttal. + +So Friedman apparently was able +to track it down and read it. + +And he wrote a detailed +letter to Einstein + +explaining to Einstein +what he got wrong, + +which is a gutsy thing +to do, but Friedman + +was right in this case. + +But Einstein was traveling and +actually never read the letter, + +at least not until much later. + +Then the following May, +Krutkov and Einstein + +are both at a conference in +Leiden, a conference that they + +were both attending, which was +a farewell lecture by Lorentz, + +who was retiring at that time. + +So they met and started +talking, and continued talking. + +And we know most about it +from a series of letters + +that Krutkov wrote to his +sister back in Saint Petersburg. + +And according to those +letters-- and I'm now + +quoting from a rather lovely +book called Alexander A. + +Friedmann-- The Man who +Made the Universe Expand, + +by Tropp, Frenkel, and Chernin. + +Krutkov wrote to his sister +that on Monday, May 7, + +1923, "I was reading, +together with Einstein, + +Friedman's article in the +Zeitschrift fur Physik. + +And then on May 18, he +wrote, "I defeated Einstein + +in the argument about Friedmann. + +Petrograd's honor is saved!" + +Petrograd is what we now +call Saint Petersburg, + +and where they were all from-- +that is, Friedman and Krutkov. + +And then shortly +after that, on May 31, + +Einstein submitted a +retraction of his refutation + +of Friedman's paper. + +And the retraction +is-- again, I'm + +quoting from Cosmological +Constant, which + +translates all these +nice papers into English. + +Einstein wrote, very briefly, +"I have in an earlier note + +criticized the cited +work-- Friedmann 1922. + +My objection rested +however, as Mr. Krutkov + +off in person and a +letter from Mr. Friedmann + +convinced me, on a +calculational error. + +I am convinced that +Mr. Friedmann's results + +are both correct and clarifying. + +They show that in addition +to the static solution + +to the field +equations, there are + +time varying solutions with a +spatially symmetric structure." + +Anyway, the expanding universe +that we now talk about. + +Einstein did have to +admit, ultimately, + +that algebra is algebra, and you +can't really futz with algebra. + +And the Einstein equations +do not imply that rho cannot + +change with time, and +that Friedman was right. + +There's an interesting twist +on this retraction letter. + +This is just a photo of +Einstein at this time period, + +and Krutkov. + +There's an interesting twist +on the retraction letter, which + +is that the original +draft still exists. + +I forget what museum it's in. + +But it's quoted in +another marvelous book + +about this history +called The Invented + +Universe, by Pierre Kerzberg. + +And I Xeroxed this +from the book. + +And this is the original draft. + +And notice there +are some cross-outs. + +And the last cross-out, which +followed this explanation + +that there is this expanding +solution-- in Einstein's + +original draft, he wrote +but then crossed out + +"a physical significance can +hardly be ascribed to them." + +So his initial instinct, +even after having + +been convinced that these +were a valid solution + +to the equations, was to say +that they couldn't possibly + +be physical, because +they're not physical. + +The universe is static. + +But somehow, before +he submitted it, + +he did realize that +there wasn't actually + +any solid logic +behind that reasoning. + +So logic did prevail, and +he decided that he really + +had no right to say +that the solution has + +no physical significance, which +is a good thing, because now, + +of course, it is the +solution that we consider + +physically significant-- the +expanding solution of Friedman. + +So [INAUDIBLE] is +a mystery, I think. + +OK, we have just a couple +minutes left in the class. + +So I think that is +nearly enough time for me + +to at least introduce what +I want to talk about next. + +What we'll be talking about next +time-- and I'll just introduce + +it now-- are a set of +two problems associated + +with the conventional +big bang theory. + +And by the conventional +bang big bang theory, + +I mean basically the theory +we've been talking about, + +but in particular, +the big bang theory + +without inflation, which we +will be talking about later. + +But so far, we've been talking +about the big bang theory + +without inflation. + +And the two problems +that we'll talk about + +are called the horizon +or horizon homogeneity + +problem, and the +flatness problem. + +Both of these are +problems connected + +with the initial conditions +necessary to make the model + +work. + +So this horizon +homogeneity problem + +is a problem about +trying to understand + +the uniformity of the observed +universe, which we've just + +put in as part of our +initial conditions. + +The model that we've +constructed was just completely + +homogeneous and isotropic +from start to present. + +The evidence for the +uniformity of the universe + +shows up most strongly, +as I think we said before, + +in the cosmic background +radiation, which + +can be measured to +fantastic precision. + +And this radiation is known to +be uniform in all directions + +to an accuracy of +one part in 100,000, + +which is really a phenomenal +level of accuracy. + +Now, what makes this +hard to understand + +in the conventional +big bang theory is + +that if instead +of just putting it + +in as an assumption about +the initial conditions, + +you try to get it out +of any kind of dynamics, + +that turns out to be impossible. + +And in particular, a calculation +that we'll do next time + +is we'll imagine +tracing back photons + +from the cosmic background +radiation arriving at the Earth + +today from two opposite +directions in the sky. + +Now, the phenomenology is +that those photons come + +with exactly the same +temperature to an accuracy + +of one part in +100,000, and that's + +what we're trying to explain. + +Now, we all do know +that systems do + +come to a uniform temperature. + +If you heated the air +in this room in a corner + +and then let the +room stand, the heat + +would scatter +throughout the room, + +and the room would come +to a uniform temperature. + +If you take a hot slice +of pizza out of the oven, + +it gets cool, as +everybody knows. + +So there is this +so-called zeroth law + +of thermodynamics which +says that everything tends + +to come to a +uniform temperature. + +And it's a fair question to +ask, can we perhaps explain + +the uniformity of the +universe by invoking + +this zeroth law +of thermodynamcs? + +Maybe the universe +just had time to come + +to a uniform temperature. + +But one can see immediately +when one looks at details + +that that's not the case. + +Within the context of +our conventional model + +of cosmology, the +universe definitely + +did not have time to come +to a uniform temperature. + +And the easiest way +to drive that home + +will be a calculation that we +will do first thing next time, + +which is that we will +trace back photons coming + +from opposite +directions in the sky + +and ask, what would +it take for them + +to have been set equal +to the same temperature + +when they were first emitted? + +And what we'll find is +that when we trace them + +back to their emission sources, +that those emissions took place + +at two points which were +separated from each other + +by about 50 horizon distances. + +So assuming that physical +influences are limited + +by the speed of +light-- and according + +to everything that we know about +the laws of physics, that's + +true-- there is no way that the +emission of that photon coming + +from that direction could +have had any causal connection + +with the emission +of the photon coming + +from the other direction. + +So if the uniformity +had to be set up + +by physical processes +that happened + +after the initial singularity, +there's just no way + +that that emission could +have known anything + +about what was +going on over there, + +and no way they could have +arranged to be emitting photons + +at the same energy +at the same time. + +Now, everything +does work if you're + +willing to just assume that +everything started at uniform. + +But if you're not +willing to assume that, + +and want to try to derive the +uniformity of the universe + +as a dynamical +consequence of processes + +in the early +universe, there's just + +no way to do it in the +conventional big bang + +theory because of this +causality argument. + +And later, we'll see that +inflation gets around that. + +Yes? + +AUDIENCE: How do we know +that the homogeneity wasn't + +just created when the +universe was smaller, + +in such a way that the +speed of light limit + +wouldn't be violated, and +that it would just maintain + +[INAUDIBLE]? + +PROFESSOR: OK, the +question is, how do we + +know that the uniformity +wasn't established when + +the universe was very small, +and then the speed of light + +might not have to be violated? + +Well, the point is +that if the dynamics is + +the conventional big bang +model, what we'll show + +is that there's +not really enough. + +No matter how early you +imagine it happening, + +it still is 50 horizon +distances apart. + +And there's no way that those +points could've communicated, + +no matter how close +you come to t equals 0. + +Now, you are of course +free to assuming anything + +you want about the +singularity at t equals 0. + +So if you want to just assume +that somehow the singularity + +homogenized +everything, that's OK. + +But there's no theory behind it. + +That's just speculation. + +But it is satisfactory +speculation. + +There's nothing it contradicts. + +But the beauty of inflation +is that it does, in fact, + +provide a dynamical explanation +for how this uniformity could + +have been created, which, +at least to many people, + +is better than just +speculating that somehow it + +happened in the singularity. + +OK, I think that's it for now. + +I will tell you about +the other problem + +we'll talk about +next time next time. + +And I will see you +all next Tuesday. \ No newline at end of file diff --git a/TTArY7ojshU.txt b/TTArY7ojshU.txt new file mode 100644 index 0000000000000000000000000000000000000000..8abcd86745aad556b41293ac0e5be358dbe5a103 --- /dev/null +++ b/TTArY7ojshU.txt @@ -0,0 +1,13872 @@ +align:start position:0% + +okay everyone let's get started uh + + align:start position:0% +okay everyone let's get started uh + + + align:start position:0% +okay everyone let's get started uh +welcome back um to uh theory of + + align:start position:0% +welcome back um to uh theory of + + + align:start position:0% +welcome back um to uh theory of +computation lecture number + + align:start position:0% +computation lecture number + + + align:start position:0% +computation lecture number +six um + + align:start position:0% +six um + + + align:start position:0% +six um +so we have + + align:start position:0% +so we have + + + align:start position:0% +so we have +been + + align:start position:0% +been + + + align:start position:0% +been +um looking + + align:start position:0% +um looking + + + align:start position:0% +um looking +at a number of different models of + + align:start position:0% +at a number of different models of + + + align:start position:0% +at a number of different models of +computation and um last lecture actually + + align:start position:0% +computation and um last lecture actually + + + align:start position:0% +computation and um last lecture actually +was an important one for us because we + + align:start position:0% +was an important one for us because we + + + align:start position:0% +was an important one for us because we +shifted gears um from our restricted + + align:start position:0% +shifted gears um from our restricted + + + align:start position:0% +shifted gears um from our restricted +model + + align:start position:0% +model + + + align:start position:0% +model +um finite autometer push down autometer + + align:start position:0% +um finite autometer push down autometer + + + align:start position:0% +um finite autometer push down autometer +and their + + align:start position:0% +and their + + + align:start position:0% +and their +Associated um generative models regular + + align:start position:0% +Associated um generative models regular + + + align:start position:0% +Associated um generative models regular +expressions and uh and context free + + align:start position:0% +expressions and uh and context free + + + align:start position:0% +expressions and uh and context free +grammars to touring machines which are + + align:start position:0% +grammars to touring machines which are + + + align:start position:0% +grammars to touring machines which are +going to be the model that we're going + + align:start position:0% +going to be the model that we're going + + + align:start position:0% +going to be the model that we're going +to which is the model that we're going + + align:start position:0% +to which is the model that we're going + + + align:start position:0% +to which is the model that we're going +to be sticking with for the rest of the + + align:start position:0% +to be sticking with for the rest of the + + + align:start position:0% +to be sticking with for the rest of the +semester because that's going to be our + + align:start position:0% +semester because that's going to be our + + + align:start position:0% +semester because that's going to be our +model as we're going to argue today for + + align:start position:0% +model as we're going to argue today for + + + align:start position:0% +model as we're going to argue today for +a general purpose + + align:start position:0% +a general purpose + + + align:start position:0% +a general purpose +computer so in a sense everything we've + + align:start position:0% +computer so in a sense everything we've + + + align:start position:0% +computer so in a sense everything we've +been doing up till now has or up until + + align:start position:0% +been doing up till now has or up until + + + align:start position:0% +been doing up till now has or up until +that point has been kind of a warm-up um + + align:start position:0% +that point has been kind of a warm-up um + + + align:start position:0% +that point has been kind of a warm-up um +but it's been um nevertheless has gotten + + align:start position:0% +but it's been um nevertheless has gotten + + + align:start position:0% +but it's been um nevertheless has gotten +chance for us to introduce some + + align:start position:0% +chance for us to introduce some + + + align:start position:0% +chance for us to introduce some +important Concepts uh that are um used + + align:start position:0% +important Concepts uh that are um used + + + align:start position:0% +important Concepts uh that are um used +in practice and also will serve as good + + align:start position:0% +in practice and also will serve as good + + + align:start position:0% +in practice and also will serve as good +examples for us moving forward and also + + align:start position:0% +examples for us moving forward and also + + + align:start position:0% +examples for us moving forward and also +just to get our you know get kind of um + + align:start position:0% +just to get our you know get kind of um + + + align:start position:0% +just to get our you know get kind of um +uh you know in in a sense on the same + + align:start position:0% +uh you know in in a sense on the same + + + align:start position:0% +uh you know in in a sense on the same +page uh + + align:start position:0% +page uh + + + align:start position:0% +page uh +so um what we're going to be doing today + + align:start position:0% +so um what we're going to be doing today + + + align:start position:0% +so um what we're going to be doing today +is um uh + + align:start position:0% +is um uh + + + align:start position:0% +is um uh +uh looking at the touring Machine model + + align:start position:0% +uh looking at the touring Machine model + + + align:start position:0% +uh looking at the touring Machine model +in a little bit more depth um one can + + align:start position:0% +in a little bit more depth um one can + + + align:start position:0% +in a little bit more depth um one can +Define touring machines in all sorts of + + align:start position:0% +Define touring machines in all sorts of + + + align:start position:0% +Define touring machines in all sorts of +different ways but it's going to turn + + align:start position:0% +different ways but it's going to turn + + + align:start position:0% +different ways but it's going to turn +out not to matter because all of those + + align:start position:0% +out not to matter because all of those + + + align:start position:0% +out not to matter because all of those +different ways are going to be + + align:start position:0% +different ways are going to be + + + align:start position:0% +different ways are going to be +equivalent to one another and so we are + + align:start position:0% +equivalent to one another and so we are + + + align:start position:0% +equivalent to one another and so we are +going to uh stick with the very simplest + + align:start position:0% +going to uh stick with the very simplest + + + align:start position:0% +going to uh stick with the very simplest +version the one we've already defined + + align:start position:0% +version the one we've already defined + + + align:start position:0% +version the one we've already defined +namely this uh the simple one tape + + align:start position:0% +namely this uh the simple one tape + + + align:start position:0% +namely this uh the simple one tape +turing machine but um where going to + + align:start position:0% +turing machine but um where going to + + + align:start position:0% +turing machine but um where going to +basically justify that by looking at + + align:start position:0% +basically justify that by looking at + + + align:start position:0% +basically justify that by looking at +some of these other models and proving + + align:start position:0% +some of these other models and proving + + + align:start position:0% +some of these other models and proving +equivalent so uh we can we look of at + + align:start position:0% +equivalent so uh we can we look of at + + + align:start position:0% +equivalent so uh we can we look of at +multi-tape touring machines we'll look + + align:start position:0% +multi-tape touring machines we'll look + + + align:start position:0% +multi-tape touring machines we'll look +at non-deterministic touring machines + + align:start position:0% +at non-deterministic touring machines + + + align:start position:0% +at non-deterministic touring machines +and we'll look at another model which is + + align:start position:0% +and we'll look at another model which is + + + align:start position:0% +and we'll look at another model which is +slightly different but is still based on + + align:start position:0% +slightly different but is still based on + + + align:start position:0% +slightly different but is still based on +tour machines called an + + align:start position:0% +tour machines called an + + + align:start position:0% +tour machines called an +enumerator and we'll show that those all + + align:start position:0% +enumerator and we'll show that those all + + + align:start position:0% +enumerator and we'll show that those all +in the end um give you the same class of + + align:start position:0% +in the end um give you the same class of + + + align:start position:0% +in the end um give you the same class of +languages and so in that sense they're + + align:start position:0% +languages and so in that sense they're + + + align:start position:0% +languages and so in that sense they're +all equivalent to one another and that's + + align:start position:0% +all equivalent to one another and that's + + + align:start position:0% +all equivalent to one another and that's +going to be serve as a kind of a + + align:start position:0% +going to be serve as a kind of a + + + align:start position:0% +going to be serve as a kind of a +motivator um kind of to in a sense + + align:start position:0% +motivator um kind of to in a sense + + + align:start position:0% +motivator um kind of to in a sense +recapitulate some of the history of the + + align:start position:0% +recapitulate some of the history of the + + + align:start position:0% +recapitulate some of the history of the +subject um and going to lead to our um + + align:start position:0% +subject um and going to lead to our um + + + align:start position:0% +subject um and going to lead to our um +discussion of what's called The Church + + align:start position:0% +discussion of what's called The Church + + + align:start position:0% +discussion of what's called The Church +Turing thesis so we will uh I'll get to + + align:start position:0% +Turing thesis so we will uh I'll get to + + + align:start position:0% +Turing thesis so we will uh I'll get to +that in due course um and we'll also + + align:start position:0% +that in due course um and we'll also + + + align:start position:0% +that in due course um and we'll also +talk about uh some notation + + align:start position:0% +talk about uh some notation + + + align:start position:0% +talk about uh some notation +for um languages and notations for + + align:start position:0% +for um languages and notations for + + + align:start position:0% +for um languages and notations for +touring machines and for coding objects + + align:start position:0% +touring machines and for coding objects + + + align:start position:0% +touring machines and for coding objects +to feed into touring machines as input + + align:start position:0% +to feed into touring machines as input + + + align:start position:0% +to feed into touring machines as input +but we'll get to that shortly as well uh + + align:start position:0% +but we'll get to that shortly as well uh + + + align:start position:0% +but we'll get to that shortly as well uh +so let's move on then we will um next um + + align:start position:0% +so let's move on then we will um next um + + + align:start position:0% +so let's move on then we will um next um +go into uh a little review of what we + + align:start position:0% +go into uh a little review of what we + + + align:start position:0% +go into uh a little review of what we +did with with for touring machines and + + align:start position:0% +did with with for touring machines and + + + align:start position:0% +did with with for touring machines and +um just want to make sure we're all + + align:start position:0% +um just want to make sure we're all + + + align:start position:0% +um just want to make sure we're all +together on that it's a very important + + align:start position:0% +together on that it's a very important + + + align:start position:0% +together on that it's a very important +concept for us this term so the turing + + align:start position:0% +concept for us this term so the turing + + + align:start position:0% +concept for us this term so the turing +machine model looks like there's going + + align:start position:0% +machine model looks like there's going + + + align:start position:0% +machine model looks like there's going +to be this finite control there's a tape + + align:start position:0% +to be this finite control there's a tape + + + align:start position:0% +to be this finite control there's a tape +with a head that can read and write on + + align:start position:0% +with a head that can read and write on + + + align:start position:0% +with a head that can read and write on +the tape can move in both directions the + + align:start position:0% +the tape can move in both directions the + + + align:start position:0% +the tape can move in both directions the +tape is infinite to the to to one side + + align:start position:0% +tape is infinite to the to to one side + + + align:start position:0% +tape is infinite to the to to one side +and so on as I've mentioned last time + + align:start position:0% +and so on as I've mentioned last time + + + align:start position:0% +and so on as I've mentioned last time +um the output of the touring machine is + + align:start position:0% +um the output of the touring machine is + + + align:start position:0% +um the output of the touring machine is +either going to be a halt accepting or + + align:start position:0% +either going to be a halt accepting or + + + align:start position:0% +either going to be a halt accepting or +rejecting or Loop that the machine may + + align:start position:0% +rejecting or Loop that the machine may + + + align:start position:0% +rejecting or Loop that the machine may +run forever with three possible outcomes + + align:start position:0% +run forever with three possible outcomes + + + align:start position:0% +run forever with three possible outcomes +for any particular input the machine May + + align:start position:0% +for any particular input the machine May + + + align:start position:0% +for any particular input the machine May +accept that input by entering Q accept + + align:start position:0% +accept that input by entering Q accept + + + align:start position:0% +accept that input by entering Q accept +May Halt and reject by entering Q reject + + align:start position:0% +May Halt and reject by entering Q reject + + + align:start position:0% +May Halt and reject by entering Q reject +and it might reject by looping which + + align:start position:0% +and it might reject by looping which + + + align:start position:0% +and it might reject by looping which +means it just never gets to the accept + + align:start position:0% +means it just never gets to the accept + + + align:start position:0% +means it just never gets to the accept +state or the uh it never gets to any + + align:start position:0% +state or the uh it never gets to any + + + align:start position:0% +state or the uh it never gets to any +halting state it just goes forever but + + align:start position:0% +halting state it just goes forever but + + + align:start position:0% +halting state it just goes forever but +we still consider that to be rejecting + + align:start position:0% +we still consider that to be rejecting + + + align:start position:0% +we still consider that to be rejecting +the input just it's rejecting by + + align:start position:0% +the input just it's rejecting by + + + align:start position:0% +the input just it's rejecting by +looping okay um and as we defined last + + align:start position:0% +looping okay um and as we defined last + + + align:start position:0% +looping okay um and as we defined last +time a language is touring recognizable + + align:start position:0% +time a language is touring recognizable + + + align:start position:0% +time a language is touring recognizable +as or as we typically write T + + align:start position:0% +as or as we typically write T + + + align:start position:0% +as or as we typically write T +recognizable if it's the language of + + align:start position:0% +recognizable if it's the language of + + + align:start position:0% +recognizable if it's the language of +some touring machine the collection of + + align:start position:0% +some touring machine the collection of + + + align:start position:0% +some touring machine the collection of +accepted strings from that touring + + align:start position:0% +accepted strings from that touring + + + align:start position:0% +accepted strings from that touring +machine again just as before machine May + + align:start position:0% +machine again just as before machine May + + + align:start position:0% +machine again just as before machine May +accept zero strings one string many + + align:start position:0% +accept zero strings one string many + + + align:start position:0% +accept zero strings one string many +strings but it always has one language + + align:start position:0% +strings but it always has one language + + + align:start position:0% +strings but it always has one language +um the collection of all accepted + + align:start position:0% +um the collection of all accepted + + + align:start position:0% +um the collection of all accepted +strings um now if you have a decider + + align:start position:0% +strings um now if you have a decider + + + align:start position:0% +strings um now if you have a decider +which is a machine that never Loops + + align:start position:0% +which is a machine that never Loops + + + align:start position:0% +which is a machine that never Loops +which always halts on every input then + + align:start position:0% +which always halts on every input then + + + align:start position:0% +which always halts on every input then +we say its language is a decidable + + align:start position:0% +we say its language is a decidable + + + align:start position:0% +we say its language is a decidable +language so we'll say a language is + + align:start position:0% +language so we'll say a language is + + + align:start position:0% +language so we'll say a language is +turning decidable or simply decidable if + + align:start position:0% +turning decidable or simply decidable if + + + align:start position:0% +turning decidable or simply decidable if +it's the language of some + + align:start position:0% +it's the language of some + + + align:start position:0% +it's the language of some +decider which is a touring machine that + + align:start position:0% +decider which is a touring machine that + + + align:start position:0% +decider which is a touring machine that +always hals on all + + align:start position:0% +always hals on all + + + align:start position:0% +always hals on all +inputs so we have those two distinct + + align:start position:0% +inputs so we have those two distinct + + + align:start position:0% +inputs so we have those two distinct +Notions touring recognizable languages + + align:start position:0% +Notions touring recognizable languages + + + align:start position:0% +Notions touring recognizable languages +and touring decidable + + align:start position:0% +and touring decidable + + + align:start position:0% +and touring decidable +languages + + align:start position:0% +languages + + + align:start position:0% +languages +um now as we're going to argue this + + align:start position:0% +um now as we're going to argue this + + + align:start position:0% +um now as we're going to argue this +lecture touring machines are going to be + + align:start position:0% +lecture touring machines are going to be + + + align:start position:0% +lecture touring machines are going to be +our model of a general general purpose + + align:start position:0% +our model of a general general purpose + + + align:start position:0% +our model of a general general purpose +computer so that's the way we're going + + align:start position:0% +computer so that's the way we're going + + + align:start position:0% +computer so that's the way we're going +to think of computers as touring + + align:start position:0% +to think of computers as touring + + + align:start position:0% +to think of computers as touring +machines + + align:start position:0% +machines + + + align:start position:0% +machines +um and um why touring machines why + + align:start position:0% +um and um why touring machines why + + + align:start position:0% +um and um why touring machines why +didn't we pick something else well the + + align:start position:0% +didn't we pick something else well the + + + align:start position:0% +didn't we pick something else well the +fact is it doesn't matter and that's + + align:start position:0% +fact is it doesn't matter and that's + + + align:start position:0% +fact is it doesn't matter and that's +going to be the point of this lecture um + + align:start position:0% +going to be the point of this lecture um + + + align:start position:0% +going to be the point of this lecture um +all reasonable models of general purpose + + align:start position:0% +all reasonable models of general purpose + + + align:start position:0% +all reasonable models of general purpose +computation um you know unrestricted um + + align:start position:0% +computation um you know unrestricted um + + + align:start position:0% +computation um you know unrestricted um +computation in the sense of not limited + + align:start position:0% +computation in the sense of not limited + + + align:start position:0% +computation in the sense of not limited +memory um are all going to be are all + + align:start position:0% +memory um are all going to be are all + + + align:start position:0% +memory um are all going to be are all +have been shown um all the models that + + align:start position:0% +have been shown um all the models that + + + align:start position:0% +have been shown um all the models that +we've ever encountered have all been + + align:start position:0% +we've ever encountered have all been + + + align:start position:0% +we've ever encountered have all been +shown to be equivalent to one another um + + align:start position:0% +shown to be equivalent to one another um + + + align:start position:0% +shown to be equivalent to one another um +and so you you're free to pick anyone + + align:start position:0% +and so you you're free to pick anyone + + + align:start position:0% +and so you you're free to pick anyone +you like and so for this course we going + + align:start position:0% +you like and so for this course we going + + + align:start position:0% +you like and so for this course we going +to pick touring machines because they're + + align:start position:0% +to pick touring machines because they're + + + align:start position:0% +to pick touring machines because they're +very simple to argue about + + align:start position:0% +very simple to argue about + + + align:start position:0% +very simple to argue about +mathematically and also they have a sort + + align:start position:0% +mathematically and also they have a sort + + + align:start position:0% +mathematically and also they have a sort +of a some element of + + align:start position:0% +of a some element of + + + align:start position:0% +of a some element of +familiarity in that you know they're + + align:start position:0% +familiarity in that you know they're + + + align:start position:0% +familiarity in that you know they're +they they feel like um you You Well they + + align:start position:0% +they they feel like um you You Well they + + + align:start position:0% +they they feel like um you You Well they +um they're more familiar than some of + + align:start position:0% +um they're more familiar than some of + + + align:start position:0% +um they're more familiar than some of +the other models that have been proposed + + align:start position:0% +the other models that have been proposed + + + align:start position:0% +the other models that have been proposed +that are out there um you know such as + + align:start position:0% +that are out there um you know such as + + + align:start position:0% +that are out there um you know such as +you know re rewriting systems Lambda + + align:start position:0% +you know re rewriting systems Lambda + + + align:start position:0% +you know re rewriting systems Lambda +calculus and so on Turing machines Feel + + align:start position:0% +calculus and so on Turing machines Feel + + + align:start position:0% +calculus and so on Turing machines Feel +Like A Primitive kind of computer and + + align:start position:0% +Like A Primitive kind of computer and + + + align:start position:0% +Like A Primitive kind of computer and +that sense they have a certain + + align:start position:0% +that sense they have a certain + + + align:start position:0% +that sense they have a certain +familiarity okay um so let's start + + align:start position:0% +familiarity okay um so let's start + + + align:start position:0% +familiarity okay um so let's start +talking about variations on the touring + + align:start position:0% +talking about variations on the touring + + + align:start position:0% +talking about variations on the touring +Machine model and we're going to argue + + align:start position:0% +Machine model and we're going to argue + + + align:start position:0% +Machine model and we're going to argue +that it doesn't make it doesn't make any + + align:start position:0% +that it doesn't make it doesn't make any + + + align:start position:0% +that it doesn't make it doesn't make any +difference + + align:start position:0% +difference + + + align:start position:0% +difference +um and then where this is going to be + + align:start position:0% +um and then where this is going to be + + + align:start position:0% +um and then where this is going to be +kind of a precursor to a discussion of a + + align:start position:0% +kind of a precursor to a discussion of a + + + align:start position:0% +kind of a precursor to a discussion of a +bit of the history of the subject that + + align:start position:0% +bit of the history of the subject that + + + align:start position:0% +bit of the history of the subject that +we going and get to in the second half + + align:start position:0% +we going and get to in the second half + + + align:start position:0% +we going and get to in the second half +of the lecture so um a multi-tape + + align:start position:0% +of the lecture so um a multi-tape + + + align:start position:0% +of the lecture so um a multi-tape +turning machine is a turning machine as + + align:start position:0% +turning machine is a turning machine as + + + align:start position:0% +turning machine is a turning machine as +you might imagine that has more than one + + align:start position:0% +you might imagine that has more than one + + + align:start position:0% +you might imagine that has more than one +well it has one or possibly more tapes + + align:start position:0% +well it has one or possibly more tapes + + + align:start position:0% +well it has one or possibly more tapes +so a single tape touring machine would + + align:start position:0% +so a single tape touring machine would + + + align:start position:0% +so a single tape touring machine would +be a + + align:start position:0% +be a + + + align:start position:0% +be a +special version of a multitape turing + + align:start position:0% +special version of a multitape turing + + + align:start position:0% +special version of a multitape turing +machine that's okay uh but you might + + align:start position:0% +machine that's okay uh but you might + + + align:start position:0% +machine that's okay uh but you might +have more than one tape um as I've shown + + align:start position:0% +have more than one tape um as I've shown + + + align:start position:0% +have more than one tape um as I've shown +in this + + align:start position:0% +in this + + + align:start position:0% +in this +diagram now uh how do we actually use a + + align:start position:0% +diagram now uh how do we actually use a + + + align:start position:0% +diagram now uh how do we actually use a +multi-tape touring machine well you + + align:start position:0% +multi-tape touring machine well you + + + align:start position:0% +multi-tape touring machine well you +present the in and we're going to see + + align:start position:0% +present the in and we're going to see + + + align:start position:0% +present the in and we're going to see +these coming up for convenience + + align:start position:0% +these coming up for convenience + + + align:start position:0% +these coming up for convenience +sometimes it's it's it's nice to be + + align:start position:0% +sometimes it's it's it's nice to be + + + align:start position:0% +sometimes it's it's it's nice to be +working with multiple tapes uh so we're + + align:start position:0% +working with multiple tapes uh so we're + + + align:start position:0% +working with multiple tapes uh so we're +going to see these later on in the + + align:start position:0% +going to see these later on in the + + + align:start position:0% +going to see these later on in the +semester a couple of times as well + + align:start position:0% +semester a couple of times as well + + + align:start position:0% +semester a couple of times as well +but for now um you know we'll we're + + align:start position:0% +but for now um you know we'll we're + + + align:start position:0% +but for now um you know we'll we're +setting the model up so that the input + + align:start position:0% +setting the model up so that the input + + + align:start position:0% +setting the model up so that the input +is going to be presented on a special + + align:start position:0% +is going to be presented on a special + + + align:start position:0% +is going to be presented on a special +input tape um so that's where the input + + align:start position:0% +input tape um so that's where the input + + + align:start position:0% +input tape um so that's where the input +appears and it's going to be followed by + + align:start position:0% +appears and it's going to be followed by + + + align:start position:0% +appears and it's going to be followed by +blanks just as we had before and now we + + align:start position:0% +blanks just as we had before and now we + + + align:start position:0% +blanks just as we had before and now we +have these potentially other tapes + + align:start position:0% +have these potentially other tapes + + + align:start position:0% +have these potentially other tapes +possibly other tapes which are we call + + align:start position:0% +possibly other tapes which are we call + + + align:start position:0% +possibly other tapes which are we call +them work tapes where the machine can uh + + align:start position:0% +them work tapes where the machine can uh + + + align:start position:0% +them work tapes where the machine can uh +write other stuff as it wishes and those + + align:start position:0% +write other stuff as it wishes and those + + + align:start position:0% +write other stuff as it wishes and those +tapes are going to be initially blank uh + + align:start position:0% +tapes are going to be initially blank uh + + + align:start position:0% +tapes are going to be initially blank uh +so just all blanks on + + align:start position:0% +so just all blanks on + + + align:start position:0% +so just all blanks on +them all of the tapes are going to be + + align:start position:0% +them all of the tapes are going to be + + + align:start position:0% +them all of the tapes are going to be +read and write so you can write on the + + align:start position:0% +read and write so you can write on the + + + align:start position:0% +read and write so you can write on the +input tape obviously you can read on + + align:start position:0% +input tape obviously you can read on + + + align:start position:0% +input tape obviously you can read on +from the input tape and you can read and + + align:start position:0% +from the input tape and you can read and + + + align:start position:0% +from the input tape and you can read and +write on the other tapes as + + align:start position:0% +write on the other tapes as + + + align:start position:0% +write on the other tapes as +well um so what we want to First + + align:start position:0% +well um so what we want to First + + + align:start position:0% +well um so what we want to First +establish that by having these + + align:start position:0% +establish that by having these + + + align:start position:0% +establish that by having these +additional tapes you don't get + + align:start position:0% +additional tapes you don't get + + + align:start position:0% +additional tapes you don't get +additional power for the machine in the + + align:start position:0% +additional power for the machine in the + + + align:start position:0% +additional power for the machine in the +sense that you're not going to + + align:start position:0% +sense that you're not going to + + + align:start position:0% +sense that you're not going to +have um uh you won't have + + align:start position:0% +have um uh you won't have + + + align:start position:0% +have um uh you won't have +additional uh um languages that you can + + align:start position:0% +additional uh um languages that you can + + + align:start position:0% +additional uh um languages that you can +recognize by virtue of having these + + align:start position:0% +recognize by virtue of having these + + + align:start position:0% +recognize by virtue of having these +additional tapes me you you could + + align:start position:0% +additional tapes me you you could + + + align:start position:0% +additional tapes me you you could +imagine that having more tapes will + + align:start position:0% +imagine that having more tapes will + + + align:start position:0% +imagine that having more tapes will +allow you to do more things um you know + + align:start position:0% +allow you to do more things um you know + + + align:start position:0% +allow you to do more things um you know +for example if you have a push down + + align:start position:0% +for example if you have a push down + + + align:start position:0% +for example if you have a push down +automaton with two stacks you can do + + align:start position:0% +automaton with two stacks you can do + + + align:start position:0% +automaton with two stacks you can do +more languages than you can with one + + align:start position:0% +more languages than you can with one + + + align:start position:0% +more languages than you can with one +stack so it's conceivable that by having + + align:start position:0% +stack so it's conceivable that by having + + + align:start position:0% +stack so it's conceivable that by having +more tapes you can do more languages + + align:start position:0% +more tapes you can do more languages + + + align:start position:0% +more tapes you can do more languages +than you could with one with one + + align:start position:0% +than you could with one with one + + + align:start position:0% +than you could with one with one +tape but in fact that's not the case one + + align:start position:0% +tape but in fact that's not the case one + + + align:start position:0% +tape but in fact that's not the case one +one tape is as good as having many tapes + + align:start position:0% +one tape is as good as having many tapes + + + align:start position:0% +one tape is as good as having many tapes +uh and we're going to prove that you + + align:start position:0% +uh and we're going to prove that you + + + align:start position:0% +uh and we're going to prove that you +know uh we're going to quickly sketch + + align:start position:0% +know uh we're going to quickly sketch + + + align:start position:0% +know uh we're going to quickly sketch +through the proof of that fact um so uh + + align:start position:0% +through the proof of that fact um so uh + + + align:start position:0% +through the proof of that fact um so uh +the theorem is that a touring machine a + + align:start position:0% +the theorem is that a touring machine a + + + align:start position:0% +the theorem is that a touring machine a +language is touring recognizable and + + align:start position:0% +language is touring recognizable and + + + align:start position:0% +language is touring recognizable and +when we say touring recognizable for now + + align:start position:0% +when we say touring recognizable for now + + + align:start position:0% +when we say touring recognizable for now +we mean just with one tape um so um + + align:start position:0% +we mean just with one tape um so um + + + align:start position:0% +we mean just with one tape um so um +that's the way we've defined it so a + + align:start position:0% +that's the way we've defined it so a + + + align:start position:0% +that's the way we've defined it so a +language is touring recognizable if and + + align:start position:0% +language is touring recognizable if and + + + align:start position:0% +language is touring recognizable if and +only if some multi-tape touring machine + + align:start position:0% +only if some multi-tape touring machine + + + align:start position:0% +only if some multi-tape touring machine +recognizes that language + + align:start position:0% +recognizes that language + + + align:start position:0% +recognizes that language +okay so really that another way of + + align:start position:0% +okay so really that another way of + + + align:start position:0% +okay so really that another way of +saying that is um if you have a language + + align:start position:0% +saying that is um if you have a language + + + align:start position:0% +saying that is um if you have a language +that you can do with a single tape you + + align:start position:0% +that you can do with a single tape you + + + align:start position:0% +that you can do with a single tape you +can do it with a multi-tape and vice + + align:start position:0% +can do it with a multi-tape and vice + + + align:start position:0% +can do it with a multi-tape and vice +versa so One Direction of that is + + align:start position:0% +versa so One Direction of that is + + + align:start position:0% +versa so One Direction of that is +immediate because a single tape touring + + align:start position:0% +immediate because a single tape touring + + + align:start position:0% +immediate because a single tape touring +machine is already a multi-tape touring + + align:start position:0% +machine is already a multi-tape touring + + + align:start position:0% +machine is already a multi-tape touring +machine that just happens to have one + + align:start position:0% +machine that just happens to have one + + + align:start position:0% +machine that just happens to have one +tape uh so the forward direction of that + + align:start position:0% +tape uh so the forward direction of that + + + align:start position:0% +tape uh so the forward direction of that +is is um there's nothing to say that's + + align:start position:0% +is is um there's nothing to say that's + + + align:start position:0% +is is um there's nothing to say that's +just immediately true um but if we want + + align:start position:0% +just immediately true um but if we want + + + align:start position:0% +just immediately true um but if we want +to prove the reverse then we're going to + + align:start position:0% +to prove the reverse then we're going to + + + align:start position:0% +to prove the reverse then we're going to +have to do some work um and the work is + + align:start position:0% +have to do some work um and the work is + + + align:start position:0% +have to do some work um and the work is +going to be showing how do you convert a + + align:start position:0% +going to be showing how do you convert a + + + align:start position:0% +going to be showing how do you convert a +multi-tape touring machine to a single + + align:start position:0% +multi-tape touring machine to a single + + + align:start position:0% +multi-tape touring machine to a single +tape touring machine so if we have + + align:start position:0% +tape touring machine so if we have + + + align:start position:0% +tape touring machine so if we have +something that's recognized by a + + align:start position:0% +something that's recognized by a + + + align:start position:0% +something that's recognized by a +multi-tape touring machine it's still + + align:start position:0% +multi-tape touring machine it's still + + + align:start position:0% +multi-tape touring machine it's still +touring recognizable and what that means + + align:start position:0% +touring recognizable and what that means + + + align:start position:0% +touring recognizable and what that means +is you can do it with a single tape + + align:start position:0% +is you can do it with a single tape + + + align:start position:0% +is you can do it with a single tape +touring machine so we have to show how + + align:start position:0% +touring machine so we have to show how + + + align:start position:0% +touring machine so we have to show how +to do the + + align:start position:0% +to do the + + + align:start position:0% +to do the +conversion and I'll kind of you know I + + align:start position:0% +conversion and I'll kind of you know I + + + align:start position:0% +conversion and I'll kind of you know I +I'll I I'll show you that I think in a + + align:start position:0% +I'll I I'll show you that I think in a + + + align:start position:0% +I'll I I'll show you that I think in a +convincing way but you know without + + align:start position:0% +convincing way but you know without + + + align:start position:0% +convincing way but you know without +getting into too much detail um so + + align:start position:0% +getting into too much detail um so + + + align:start position:0% +getting into too much detail um so +here's an image of a multi-tape touring + + align:start position:0% +here's an image of a multi-tape touring + + + align:start position:0% +here's an image of a multi-tape touring +machine in during the course of its + + align:start position:0% +machine in during the course of its + + + align:start position:0% +machine in during the course of its +input so it has already we've already + + align:start position:0% +input so it has already we've already + + + align:start position:0% +input so it has already we've already +started it off um you know initially it + + align:start position:0% +started it off um you know initially it + + + align:start position:0% +started it off um you know initially it +starts off with the um other tapes the + + align:start position:0% +starts off with the um other tapes the + + + align:start position:0% +starts off with the um other tapes the +work tapes being all blank but now it's + + align:start position:0% +work tapes being all blank but now it's + + + align:start position:0% +work tapes being all blank but now it's +processed for a while and you know the + + align:start position:0% +processed for a while and you know the + + + align:start position:0% +processed for a while and you know the +head on the input tape is now has moved + + align:start position:0% +head on the input tape is now has moved + + + align:start position:0% +head on the input tape is now has moved +off from its starting position at the + + align:start position:0% +off from its starting position at the + + + align:start position:0% +off from its starting position at the +left end it's somewhere in the middle + + align:start position:0% +left end it's somewhere in the middle + + + align:start position:0% +left end it's somewhere in the middle +it's written stuff on the other + + align:start position:0% +it's written stuff on the other + + + align:start position:0% +it's written stuff on the other +tapes and what we want to is show how to + + align:start position:0% +tapes and what we want to is show how to + + + align:start position:0% +tapes and what we want to is show how to +represent that same + + align:start position:0% +represent that same + + + align:start position:0% +represent that same +information on a single tape touring + + align:start position:0% +information on a single tape touring + + + align:start position:0% +information on a single tape touring +machine in a way which allows the single + + align:start position:0% +machine in a way which allows the single + + + align:start position:0% +machine in a way which allows the single +tape touring machine to carry out the + + align:start position:0% +tape touring machine to carry out the + + + align:start position:0% +tape touring machine to carry out the +steps of the multi-tape touring machine + + align:start position:0% +steps of the multi-tape touring machine + + + align:start position:0% +steps of the multi-tape touring machine +but using only its single tape by virtue + + align:start position:0% +but using only its single tape by virtue + + + align:start position:0% +but using only its single tape by virtue +of some kind of a data structure which + + align:start position:0% +of some kind of a data structure which + + + align:start position:0% +of some kind of a data structure which +allows for the simulation to to go + + align:start position:0% +allows for the simulation to to go + + + align:start position:0% +allows for the simulation to to go +forward okay so how is the simul the + + align:start position:0% +forward okay so how is the simul the + + + align:start position:0% +forward okay so how is the simul the +single tape touring machine going to be + + align:start position:0% +single tape touring machine going to be + + + align:start position:0% +single tape touring machine going to be +simulating going to be carrying out the + + align:start position:0% +simulating going to be carrying out the + + + align:start position:0% +simulating going to be carrying out the +the the same effect of having these + + align:start position:0% +the the same effect of having these + + + align:start position:0% +the the same effect of having these +multiple types on the multi-tape touring + + align:start position:0% +multiple types on the multi-tape touring + + + align:start position:0% +multiple types on the multi-tape touring +machine so here's a picture of the + + align:start position:0% +machine so here's a picture of the + + + align:start position:0% +machine so here's a picture of the +single tape touring machine it just has + + align:start position:0% +single tape touring machine it just has + + + align:start position:0% +single tape touring machine it just has +one + + align:start position:0% +one + + + align:start position:0% +one +tape by the way I should mention that + + align:start position:0% +tape by the way I should mention that + + + align:start position:0% +tape by the way I should mention that +all of the tapes are infinite to the + + align:start position:0% +all of the tapes are infinite to the + + + align:start position:0% +all of the tapes are infinite to the +right um in the multi-tape touring + + align:start position:0% +right um in the multi-tape touring + + + align:start position:0% +right um in the multi-tape touring +machine just as we had for the single + + align:start position:0% +machine just as we had for the single + + + align:start position:0% +machine just as we had for the single +tape touring machine and now uh with + + align:start position:0% +tape touring machine and now uh with + + + align:start position:0% +tape touring machine and now uh with +this uh single tape turning machine it's + + align:start position:0% +this uh single tape turning machine it's + + + align:start position:0% +this uh single tape turning machine it's +going to represent the information that + + align:start position:0% +going to represent the information that + + + align:start position:0% +going to represent the information that +was on that's present on these multiple + + align:start position:0% +was on that's present on these multiple + + + align:start position:0% +was on that's present on these multiple +tapes but using only the single tape and + + align:start position:0% +tapes but using only the single tape and + + + align:start position:0% +tapes but using only the single tape and +the way I'm choosing to do that is going + + align:start position:0% +the way I'm choosing to do that is going + + + align:start position:0% +the way I'm choosing to do that is going +to be particularly simple um I'm going + + align:start position:0% +to be particularly simple um I'm going + + + align:start position:0% +to be particularly simple um I'm going +to just divide up so here I'm saying it + + align:start position:0% +to just divide up so here I'm saying it + + + align:start position:0% +to just divide up so here I'm saying it +in words uh it's going to simulate in by + + align:start position:0% +in words uh it's going to simulate in by + + + align:start position:0% +in words uh it's going to simulate in by +storing the contents of the multitape on + + align:start position:0% +storing the contents of the multitape on + + + align:start position:0% +storing the contents of the multitape on +the single tape in separate blocks so + + align:start position:0% +the single tape in separate blocks so + + + align:start position:0% +the single tape in separate blocks so +I'm basically going to divide up the + + align:start position:0% +I'm basically going to divide up the + + + align:start position:0% +I'm basically going to divide up the +single tape uh touring machines tape + + align:start position:0% +single tape uh touring machines tape + + + align:start position:0% +single tape uh touring machines tape +into separate regions where each one of + + align:start position:0% +into separate regions where each one of + + + align:start position:0% +into separate regions where each one of +those regions is going to have the + + align:start position:0% +those regions is going to have the + + + align:start position:0% +those regions is going to have the +information that was on one of the + + align:start position:0% +information that was on one of the + + + align:start position:0% +information that was on one of the +tapes in the um multi-tape + + align:start position:0% +tapes in the um multi-tape + + + align:start position:0% +tapes in the um multi-tape +machine so for example here is on the + + align:start position:0% +machine so for example here is on the + + + align:start position:0% +machine so for example here is on the +first tape it's got a a BBA well that's + + align:start position:0% +first tape it's got a a BBA well that's + + + align:start position:0% +first tape it's got a a BBA well that's +going to appear here in that first block + + align:start position:0% +going to appear here in that first block + + + align:start position:0% +going to appear here in that first block +on the single tape turning machine + + align:start position:0% +on the single tape turning machine + + + align:start position:0% +on the single tape turning machine +okay sort of seeing it float down to + + align:start position:0% +okay sort of seeing it float down to + + + align:start position:0% +okay sort of seeing it float down to +suggest that it's coming from this + + align:start position:0% +suggest that it's coming from this + + + align:start position:0% +suggest that it's coming from this +multi-tape touring machine but that's + + align:start position:0% +multi-tape touring machine but that's + + + align:start position:0% +multi-tape touring machine but that's +really been developed by the simulation + + align:start position:0% +really been developed by the simulation + + + align:start position:0% +really been developed by the simulation +that the single tape touring machine has + + align:start position:0% +that the single tape touring machine has + + + align:start position:0% +that the single tape touring machine has +obviously the single tape turning + + align:start position:0% +obviously the single tape turning + + + align:start position:0% +obviously the single tape turning +machine doesn't have any direct access + + align:start position:0% +machine doesn't have any direct access + + + align:start position:0% +machine doesn't have any direct access +to the multitape machine but it's going + + align:start position:0% +to the multitape machine but it's going + + + align:start position:0% +to the multitape machine but it's going +to be + + align:start position:0% +to be + + + align:start position:0% +to be +simulating so this is how we're showing + + align:start position:0% +simulating so this is how we're showing + + + align:start position:0% +simulating so this is how we're showing +the data is being stored on the single + + align:start position:0% +the data is being stored on the single + + + align:start position:0% +the data is being stored on the single +tape machine's tape so in the second + + align:start position:0% +tape machine's tape so in the second + + + align:start position:0% +tape machine's tape so in the second +Block it's going to have the contents of + + align:start position:0% +Block it's going to have the contents of + + + align:start position:0% +Block it's going to have the contents of +the second uh tape of the touring + + align:start position:0% +the second uh tape of the touring + + + align:start position:0% +the second uh tape of the touring +multitape + + align:start position:0% +multitape + + + align:start position:0% +multitape +machine and the uh the final um uh + + align:start position:0% +machine and the uh the final um uh + + + align:start position:0% +machine and the uh the final um uh +region of the single tapes the final + + align:start position:0% +region of the single tapes the final + + + align:start position:0% +region of the single tapes the final +block so-called of the single tapes tape + + align:start position:0% +block so-called of the single tapes tape + + + align:start position:0% +block so-called of the single tapes tape +is going to have single tape machine's + + align:start position:0% +is going to have single tape machine's + + + align:start position:0% +is going to have single tape machine's +tape is going to have the the rest of + + align:start position:0% +tape is going to have the the rest of + + + align:start position:0% +tape is going to have the the rest of +the + + align:start position:0% +the + + + align:start position:0% +the +um the contents of the last tape of of M + + align:start position:0% +um the contents of the last tape of of M + + + align:start position:0% +um the contents of the last tape of of M +and then it's going to be followed by + + align:start position:0% +and then it's going to be followed by + + + align:start position:0% +and then it's going to be followed by +the same infinitely many blanks that + + align:start position:0% +the same infinitely many blanks that + + + align:start position:0% +the same infinitely many blanks that +each of these um uh tapes are going to + + align:start position:0% +each of these um uh tapes are going to + + + align:start position:0% +each of these um uh tapes are going to +have uh following the portion that they + + align:start position:0% +have uh following the portion that they + + + align:start position:0% +have uh following the portion that they +may have written during the course of + + align:start position:0% +may have written during the course of + + + align:start position:0% +may have written during the course of +their + + align:start position:0% +their + + + align:start position:0% +their +computation okay um so that's what the + + align:start position:0% +computation okay um so that's what the + + + align:start position:0% +computation okay um so that's what the +single tape touring machine's tape is + + align:start position:0% +single tape touring machine's tape is + + + align:start position:0% +single tape touring machine's tape is +going to look like during the course of + + align:start position:0% +going to look like during the course of + + + align:start position:0% +going to look like during the course of +its computation it's going to have the + + align:start position:0% +its computation it's going to have the + + + align:start position:0% +its computation it's going to have the +information represented in these blocks + + align:start position:0% +information represented in these blocks + + + align:start position:0% +information represented in these blocks +capturing all of the information that + + align:start position:0% +capturing all of the information that + + + align:start position:0% +capturing all of the information that +the multi-tape touring machine has in a + + align:start position:0% +the multi-tape touring machine has in a + + + align:start position:0% +the multi-tape touring machine has in a +perhaps somewhat less convenient way + + align:start position:0% +perhaps somewhat less convenient way + + + align:start position:0% +perhaps somewhat less convenient way +because the multi-tape touring machine + + align:start position:0% +because the multi-tape touring machine + + + align:start position:0% +because the multi-tape touring machine +you know we didn't really make this + + align:start position:0% +you know we didn't really make this + + + align:start position:0% +you know we didn't really make this +explicit and in part because it doesn't + + align:start position:0% +explicit and in part because it doesn't + + + align:start position:0% +explicit and in part because it doesn't +really matter we didn't say exactly how + + align:start position:0% +really matter we didn't say exactly how + + + align:start position:0% +really matter we didn't say exactly how +the multi-tape touring machine operates + + align:start position:0% +the multi-tape touring machine operates + + + align:start position:0% +the multi-tape touring machine operates +what I have in mind is that the + + align:start position:0% +what I have in mind is that the + + + align:start position:0% +what I have in mind is that the +multi-tape touring machine can read and + + align:start position:0% +multi-tape touring machine can read and + + + align:start position:0% +multi-tape touring machine can read and +move all of its heads from all of its + + align:start position:0% +move all of its heads from all of its + + + align:start position:0% +move all of its heads from all of its +heads in one step + + align:start position:0% +heads in one step + + + align:start position:0% +heads in one step +so in a single step of the multitape + + align:start position:0% +so in a single step of the multitape + + + align:start position:0% +so in a single step of the multitape +machine it can it can obtain the + + align:start position:0% +machine it can it can obtain the + + + align:start position:0% +machine it can it can obtain the +information that's underneath each of + + align:start position:0% +information that's underneath each of + + + align:start position:0% +information that's underneath each of +its heads feed that into its transition + + align:start position:0% +its heads feed that into its transition + + + align:start position:0% +its heads feed that into its transition +function and then together with the + + align:start position:0% +function and then together with the + + + align:start position:0% +function and then together with the +state of the multitape machine decide + + align:start position:0% +state of the multitape machine decide + + + align:start position:0% +state of the multitape machine decide +how to change each of those locations + + align:start position:0% +how to change each of those locations + + + align:start position:0% +how to change each of those locations +and then how to move each one of those + + align:start position:0% +and then how to move each one of those + + + align:start position:0% +and then how to move each one of those +heads so it's kind of operating on all + + align:start position:0% +heads so it's kind of operating on all + + + align:start position:0% +heads so it's kind of operating on all +of the tapes in + + align:start position:0% + + + + align:start position:0% + +parallel okay so now uh how how does the + + align:start position:0% +parallel okay so now uh how how does the + + + align:start position:0% +parallel okay so now uh how how does the +actual steps of the simulation of the + + align:start position:0% +actual steps of the simulation of the + + + align:start position:0% +actual steps of the simulation of the +single tape you know by the single tape + + align:start position:0% +single tape you know by the single tape + + + align:start position:0% +single tape you know by the single tape +um machine had as a go so first of + + align:start position:0% +um machine had as a go so first of + + + align:start position:0% +um machine had as a go so first of +all besides storing the contents of each + + align:start position:0% +all besides storing the contents of each + + + align:start position:0% +all besides storing the contents of each +of the tapes in in s's single + + align:start position:0% +of the tapes in in s's single + + + align:start position:0% +of the tapes in in s's single +tape there's some additional information + + align:start position:0% +tape there's some additional information + + + align:start position:0% +tape there's some additional information +that it needs to record + + align:start position:0% +that it needs to record + + + align:start position:0% +that it needs to record +namely um M has a head for each one of + + align:start position:0% +namely um M has a head for each one of + + + align:start position:0% +namely um M has a head for each one of +its tapes + + align:start position:0% +its tapes + + + align:start position:0% +its tapes +but s has just a single + + align:start position:0% +but s has just a single + + + align:start position:0% +but s has just a single +head and each of M's heads could be in + + align:start position:0% +head and each of M's heads could be in + + + align:start position:0% +head and each of M's heads could be in +some different location you know in this + + align:start position:0% +some different location you know in this + + + align:start position:0% +some different location you know in this +case as I've shown it on the first tape + + align:start position:0% +case as I've shown it on the first tape + + + align:start position:0% +case as I've shown it on the first tape +it's headed in location three on the + + align:start position:0% +it's headed in location three on the + + + align:start position:0% +it's headed in location three on the +second tape it's in location two on the + + align:start position:0% +second tape it's in location two on the + + + align:start position:0% +second tape it's in location two on the +third tape it's on location on the last + + align:start position:0% +third tape it's on location on the last + + + align:start position:0% +third tape it's on location on the last +tape it's in location one uh so where + + align:start position:0% +tape it's in location one uh so where + + + align:start position:0% +tape it's in location one uh so where +were we we were simulating the + + align:start position:0% +were we we were simulating the + + + align:start position:0% +were we we were simulating the +multi-tape touring machine with the + + align:start position:0% +multi-tape touring machine with the + + + align:start position:0% +multi-tape touring machine with the +single tape touring machine and we had + + align:start position:0% +single tape touring machine and we had + + + align:start position:0% +single tape touring machine and we had +to keep track of where the heads are + + align:start position:0% +to keep track of where the heads are + + + align:start position:0% +to keep track of where the heads are +um and so we're going to do that by + + align:start position:0% +um and so we're going to do that by + + + align:start position:0% +um and so we're going to do that by +writing the locations on those + + align:start position:0% +writing the locations on those + + + align:start position:0% +writing the locations on those +blocks okay so we're going to have a + + align:start position:0% +blocks okay so we're going to have a + + + align:start position:0% +blocks okay so we're going to have a +special dot as I've shown here to + + align:start position:0% +special dot as I've shown here to + + + align:start position:0% +special dot as I've shown here to +represent the location of the head in + + align:start position:0% +represent the location of the head in + + + align:start position:0% +represent the location of the head in +that very first block so the head's on + + align:start position:0% +that very first block so the head's on + + + align:start position:0% +that very first block so the head's on +the B I'm going to dot the B and I'm + + align:start position:0% +the B I'm going to dot the B and I'm + + + align:start position:0% +the B I'm going to dot the B and I'm +going to do the same thing for the + + align:start position:0% +going to do the same thing for the + + + align:start position:0% +going to do the same thing for the +locations of the others um + + align:start position:0% +locations of the others um + + + align:start position:0% +locations of the others um +heads and how am I getting that effect + + align:start position:0% +heads and how am I getting that effect + + + align:start position:0% +heads and how am I getting that effect +well we've had seen something like that + + align:start position:0% +well we've had seen something like that + + + align:start position:0% +well we've had seen something like that +before where we just expand the tape + + align:start position:0% +before where we just expand the tape + + + align:start position:0% +before where we just expand the tape +alphabet of s to allow for these dotted + + align:start position:0% +alphabet of s to allow for these dotted + + + align:start position:0% +alphabet of s to allow for these dotted +symbols as well as the uh irregular + + align:start position:0% +symbols as well as the uh irregular + + + align:start position:0% +symbols as well as the uh irregular +symbols we also have expanded it to + + align:start position:0% +symbols we also have expanded it to + + + align:start position:0% +symbols we also have expanded it to +include the the limiter markers that + + align:start position:0% +include the the limiter markers that + + + align:start position:0% +include the the limiter markers that +separate the blocks one one another + + align:start position:0% +separate the blocks one one another + + + align:start position:0% +separate the blocks one one another +which I'm writing as a pound sign um so + + align:start position:0% +which I'm writing as a pound sign um so + + + align:start position:0% +which I'm writing as a pound sign um so +we can just get that effect simply by + + align:start position:0% +we can just get that effect simply by + + + align:start position:0% +we can just get that effect simply by +expanding the tape alphabet of s okay a + + align:start position:0% +expanding the tape alphabet of s okay a + + + align:start position:0% +expanding the tape alphabet of s okay a +few more details of s that are just + + align:start position:0% +few more details of s that are just + + + align:start position:0% +few more details of s that are just +worth looking at just to make sure we're + + align:start position:0% +worth looking at just to make sure we're + + + align:start position:0% +worth looking at just to make sure we're +kind of all understanding what's + + align:start position:0% +kind of all understanding what's + + + align:start position:0% +kind of all understanding what's +happening so for every time M takes one + + align:start position:0% +happening so for every time M takes one + + + align:start position:0% +happening so for every time M takes one +step s has actually a lot of work to do + + align:start position:0% +step s has actually a lot of work to do + + + align:start position:0% +step s has actually a lot of work to do +because one step of M it can move all of + + align:start position:0% +because one step of M it can move all of + + + align:start position:0% +because one step of M it can move all of +those read read and move all of those + + align:start position:0% +those read read and move all of those + + + align:start position:0% +those read read and move all of those +heads all at one shot s has to scan the + + align:start position:0% +heads all at one shot s has to scan the + + + align:start position:0% +heads all at one shot s has to scan the +entire tape to see what those what's + + align:start position:0% +entire tape to see what those what's + + + align:start position:0% +entire tape to see what those what's +underneath those in effect virtual heads + + align:start position:0% +underneath those in effect virtual heads + + + align:start position:0% +underneath those in effect virtual heads +which are the locations of the dotted + + align:start position:0% +which are the locations of the dotted + + + align:start position:0% +which are the locations of the dotted +symbols it has to see what's underneath + + align:start position:0% +symbols it has to see what's underneath + + + align:start position:0% +symbols it has to see what's underneath +each one of those + + align:start position:0% +each one of those + + + align:start position:0% +each one of those +heads um uh to see how to update the + + align:start position:0% +heads um uh to see how to update the + + + align:start position:0% +heads um uh to see how to update the +transition you know update its state to + + align:start position:0% +transition you know update its state to + + + align:start position:0% +transition you know update its state to +the next state and then it has to scan + + align:start position:0% +the next state and then it has to scan + + + align:start position:0% +the next state and then it has to scan +again to um change the the location + + align:start position:0% +again to um change the the location + + + align:start position:0% +again to um change the the location +change the contents of those of those + + align:start position:0% +change the contents of those of those + + + align:start position:0% +change the contents of those of those +tape locations and also to move the head + + align:start position:0% +tape locations and also to move the head + + + align:start position:0% +tape locations and also to move the head +left or right by moving the effectively + + align:start position:0% +left or right by moving the effectively + + + align:start position:0% +left or right by moving the effectively +now moving the dot left or right so + + align:start position:0% +now moving the dot left or right so + + + align:start position:0% +now moving the dot left or right so +that's pretty straightforward + + align:start position:0% +that's pretty straightforward + + + align:start position:0% +that's pretty straightforward +uh uh there's one application that can + + align:start position:0% +uh uh there's one application that can + + + align:start position:0% +uh uh there's one application that can +occur however um which is that what + + align:start position:0% +occur however um which is that what + + + align:start position:0% +occur however um which is that what +happens if um on one of the tapes let's + + align:start position:0% +happens if um on one of the tapes let's + + + align:start position:0% +happens if um on one of the tapes let's +say m starts using writing more content + + align:start position:0% +say m starts using writing more content + + + align:start position:0% +say m starts using writing more content +then you have room in that + + align:start position:0% +then you have room in that + + + align:start position:0% +then you have room in that +block uh to store that + + align:start position:0% +block uh to store that + + + align:start position:0% +block uh to store that +information you know so if M like moves + + align:start position:0% +information you know so if M like moves + + + align:start position:0% +information you know so if M like moves +it has one1 suppose M you know after a + + align:start position:0% +it has one1 suppose M you know after a + + + align:start position:0% +it has one1 suppose M you know after a +few steps moves its head into the + + align:start position:0% +few steps moves its head into the + + + align:start position:0% +few steps moves its head into the +original blank portion of the tape and + + align:start position:0% +original blank portion of the tape and + + + align:start position:0% +original blank portion of the tape and +writes another symbol there we we have + + align:start position:0% +writes another symbol there we we have + + + align:start position:0% +writes another symbol there we we have +to put that symbol somewhere because we + + align:start position:0% +to put that symbol somewhere because we + + + align:start position:0% +to put that symbol somewhere because we +have to record all that information and + + align:start position:0% +have to record all that information and + + + align:start position:0% +have to record all that information and +the block is like full so what do we do + + align:start position:0% +the block is like full so what do we do + + + align:start position:0% +the block is like full so what do we do +well in that case s goes to like a + + align:start position:0% +well in that case s goes to like a + + + align:start position:0% +well in that case s goes to like a +little interrupt routine and + + align:start position:0% +little interrupt routine and + + + align:start position:0% +little interrupt routine and +uh moves shifts all of the symbols um to + + align:start position:0% +uh moves shifts all of the symbols um to + + + align:start position:0% +uh moves shifts all of the symbols um to +the right one place to make open up um a + + align:start position:0% +the right one place to make open up um a + + + align:start position:0% +the right one place to make open up um a +location here where it can write a new + + align:start position:0% +location here where it can write a new + + + align:start position:0% +location here where it can write a new +symbol for uh carrying continuing the + + align:start position:0% +symbol for uh carrying continuing the + + + align:start position:0% +symbol for uh carrying continuing the +simulation so with that in mind uh s can + + align:start position:0% +simulation so with that in mind uh s can + + + align:start position:0% +simulation so with that in mind uh s can +maintain the current contents of each of + + align:start position:0% +maintain the current contents of each of + + + align:start position:0% +maintain the current contents of each of +M's tapes and um let me just note that + + align:start position:0% +M's tapes and um let me just note that + + + align:start position:0% +M's tapes and um let me just note that +here shift to add room is + + align:start position:0% +here shift to add room is + + + align:start position:0% +here shift to add room is +needed and that's all that happens in + + align:start position:0% +needed and that's all that happens in + + + align:start position:0% +needed and that's all that happens in +this during the course of the simulation + + align:start position:0% +this during the course of the simulation + + + align:start position:0% +this during the course of the simulation +okay and if of course if S as it's + + align:start position:0% +okay and if of course if S as it's + + + align:start position:0% +okay and if of course if S as it's +simulating m observes that M comes to an + + align:start position:0% +simulating m observes that M comes to an + + + align:start position:0% +simulating m observes that M comes to an +accept or rejects + + align:start position:0% +accept or rejects + + + align:start position:0% +accept or rejects +uh s should do the + + align:start position:0% +uh s should do the + + + align:start position:0% +uh s should do the +same okay so that that's our description + + align:start position:0% +same okay so that that's our description + + + align:start position:0% +same okay so that that's our description +of how the simulation of the the single + + align:start position:0% +of how the simulation of the the single + + + align:start position:0% +of how the simulation of the the single +tape simulation of the multi-tape + + align:start position:0% +tape simulation of the multi-tape + + + align:start position:0% +tape simulation of the multi-tape +machine works right okay let's turn to + + align:start position:0% +machine works right okay let's turn to + + + align:start position:0% +machine works right okay let's turn to +non-deterministic machines + + align:start position:0% +non-deterministic machines + + + align:start position:0% +non-deterministic machines +now if you remember for find out and I + + align:start position:0% +now if you remember for find out and I + + + align:start position:0% +now if you remember for find out and I +hope you do for find out atoma we had + + align:start position:0% +hope you do for find out atoma we had + + + align:start position:0% +hope you do for find out atoma we had +equivalence between non-deterministic + + align:start position:0% +equivalence between non-deterministic + + + align:start position:0% +equivalence between non-deterministic +and + + align:start position:0% +and + + + align:start position:0% +and +deterministic um find autometer for push + + align:start position:0% +deterministic um find autometer for push + + + align:start position:0% +deterministic um find autometer for push +down autometer we did not have + + align:start position:0% +down autometer we did not have + + + align:start position:0% +down autometer we did not have +equivalence we didn't prove that but we + + align:start position:0% +equivalence we didn't prove that but we + + + align:start position:0% +equivalence we didn't prove that but we +just stated it as a fact there are + + align:start position:0% +just stated it as a fact there are + + + align:start position:0% +just stated it as a fact there are +certain languages that you can do with + + align:start position:0% +certain languages that you can do with + + + align:start position:0% +certain languages that you can do with +non-deterministic push down autometer + + align:start position:0% +non-deterministic push down autometer + + + align:start position:0% +non-deterministic push down autometer +which is the model we typically hold as + + align:start position:0% +which is the model we typically hold as + + + align:start position:0% +which is the model we typically hold as +our standard so that some things you can + + align:start position:0% +our standard so that some things you can + + + align:start position:0% +our standard so that some things you can +do with non-deterministic push down + + align:start position:0% +do with non-deterministic push down + + + align:start position:0% +do with non-deterministic push down +automa that you cannot do with + + align:start position:0% +automa that you cannot do with + + + align:start position:0% +automa that you cannot do with +deterministic push down autom um you + + align:start position:0% +deterministic push down autom um you + + + align:start position:0% +deterministic push down autom um you +really need the non-determinism they're + + align:start position:0% +really need the non-determinism they're + + + align:start position:0% +really need the non-determinism they're +not not equivalent for Turing machines + + align:start position:0% +not not equivalent for Turing machines + + + align:start position:0% +not not equivalent for Turing machines +uh we're going to get the equivalents + + align:start position:0% +uh we're going to get the equivalents + + + align:start position:0% +uh we're going to get the equivalents +back so we show that anything you can do + + align:start position:0% +back so we show that anything you can do + + + align:start position:0% +back so we show that anything you can do +with a non-deterministic touring machine + + align:start position:0% +with a non-deterministic touring machine + + + align:start position:0% +with a non-deterministic touring machine +in terms of language recognition you can + + align:start position:0% +in terms of language recognition you can + + + align:start position:0% +in terms of language recognition you can +also do with a deterministic turning + + align:start position:0% +also do with a deterministic turning + + + align:start position:0% +also do with a deterministic turning +machine so remember we kind of mentioned + + align:start position:0% +machine so remember we kind of mentioned + + + align:start position:0% +machine so remember we kind of mentioned +this briefly last time the + + align:start position:0% +this briefly last time the + + + align:start position:0% +this briefly last time the +non-deterministic turning machine looks + + align:start position:0% +non-deterministic turning machine looks + + + align:start position:0% +non-deterministic turning machine looks +exactly like a deterministic turning + + align:start position:0% +exactly like a deterministic turning + + + align:start position:0% +exactly like a deterministic turning +machine except for the transition + + align:start position:0% +machine except for the transition + + + align:start position:0% +machine except for the transition +function where we have this power set + + align:start position:0% +function where we have this power set + + + align:start position:0% +function where we have this power set +which allows for multiple different + + align:start position:0% +which allows for multiple different + + + align:start position:0% +which allows for multiple different +outcomes at a given step instead of just + + align:start position:0% +outcomes at a given step instead of just + + + align:start position:0% +outcomes at a given step instead of just +a single outcome that you would have in + + align:start position:0% +a single outcome that you would have in + + + align:start position:0% +a single outcome that you would have in +a deterministic uh machine so we + + align:start position:0% +a deterministic uh machine so we + + + align:start position:0% +a deterministic uh machine so we +represent that with this power set here + + align:start position:0% +represent that with this power set here + + + align:start position:0% +represent that with this power set here +um uh applied to the possibilities that + + align:start position:0% +um uh applied to the possibilities that + + + align:start position:0% +um uh applied to the possibilities that +um the machine would have as the um next + + align:start position:0% +um the machine would have as the um next + + + align:start position:0% +um the machine would have as the um next +uh Next + + align:start position:0% +uh Next + + + align:start position:0% +uh Next +Step okay um so now we're going to prove + + align:start position:0% +Step okay um so now we're going to prove + + + align:start position:0% +Step okay um so now we're going to prove +a very similar theorem that a is touring + + align:start position:0% +a very similar theorem that a is touring + + + align:start position:0% +a very similar theorem that a is touring +recognizable by an ordinary one tape + + align:start position:0% +recognizable by an ordinary one tape + + + align:start position:0% +recognizable by an ordinary one tape +touring machine that kind of goes + + align:start position:0% +touring machine that kind of goes + + + align:start position:0% +touring machine that kind of goes +without saying so that's we how we + + align:start position:0% +without saying so that's we how we + + + align:start position:0% +without saying so that's we how we +defined it a is touring recognizable if + + align:start position:0% +defined it a is touring recognizable if + + + align:start position:0% +defined it a is touring recognizable if +and only if some non-deterministic + + align:start position:0% +and only if some non-deterministic + + + align:start position:0% +and only if some non-deterministic +touring machine recognizes that + + align:start position:0% +touring machine recognizes that + + + align:start position:0% +touring machine recognizes that +language + + align:start position:0% +language + + + align:start position:0% +language +okay um again remember we're using + + align:start position:0% +okay um again remember we're using + + + align:start position:0% +okay um again remember we're using +non-determinism in the way we always do + + align:start position:0% +non-determinism in the way we always do + + + align:start position:0% +non-determinism in the way we always do +namely that uh a non-deterministic + + align:start position:0% +namely that uh a non-deterministic + + + align:start position:0% +namely that uh a non-deterministic +machine accepts if there is some Branch + + align:start position:0% +machine accepts if there is some Branch + + + align:start position:0% +machine accepts if there is some Branch +or some thread of it's not computation + + align:start position:0% +or some thread of it's not computation + + + align:start position:0% +or some thread of it's not computation +ends up at an accept other branches + + align:start position:0% +ends up at an accept other branches + + + align:start position:0% +ends up at an accept other branches +might go forever or might reject part + + align:start position:0% +might go forever or might reject part + + + align:start position:0% +might go forever or might reject part +way part of the way through um but + + align:start position:0% +way part of the way through um but + + + align:start position:0% +way part of the way through um but +acceptance always overrules them if any + + align:start position:0% +acceptance always overrules them if any + + + align:start position:0% +acceptance always overrules them if any +branch accepts that's how + + align:start position:0% +branch accepts that's how + + + align:start position:0% +branch accepts that's how +non-determinism works for us okay so + + align:start position:0% +non-determinism works for us okay so + + + align:start position:0% +non-determinism works for us okay so +now the forward direction of this is + + align:start position:0% +now the forward direction of this is + + + align:start position:0% +now the forward direction of this is +again just like before immediate because + + align:start position:0% +again just like before immediate because + + + align:start position:0% +again just like before immediate because +a deterministic turing machine is a + + align:start position:0% +a deterministic turing machine is a + + + align:start position:0% +a deterministic turing machine is a +special kind of non-deterministic turing + + align:start position:0% +special kind of non-deterministic turing + + + align:start position:0% +special kind of non-deterministic turing +machine which never branches U + + align:start position:0% +machine which never branches U + + + align:start position:0% +machine which never branches U +non-deterministically on any of its + + align:start position:0% +non-deterministically on any of its + + + align:start position:0% +non-deterministically on any of its +steps um so that forward direction is + + align:start position:0% +steps um so that forward direction is + + + align:start position:0% +steps um so that forward direction is +immediate the backwards definition is + + align:start position:0% +immediate the backwards definition is + + + align:start position:0% +immediate the backwards definition is +where we're going to have to do some + + align:start position:0% +where we're going to have to do some + + + align:start position:0% +where we're going to have to do some +work converting our non-deterministic + + align:start position:0% +work converting our non-deterministic + + + align:start position:0% +work converting our non-deterministic +turning machine to a deterministic + + align:start position:0% +turning machine to a deterministic + + + align:start position:0% +turning machine to a deterministic +turning machine and we'll do so as + + align:start position:0% +turning machine and we'll do so as + + + align:start position:0% +turning machine and we'll do so as +follows we'll take a non-deterministic + + align:start position:0% +follows we'll take a non-deterministic + + + align:start position:0% +follows we'll take a non-deterministic +turning machine uh here's our picture + + align:start position:0% +turning machine uh here's our picture + + + align:start position:0% +turning machine uh here's our picture +and we're going to now um imagine its + + align:start position:0% +and we're going to now um imagine its + + + align:start position:0% +and we're going to now um imagine its +computation in terms of a tree um and so + + align:start position:0% +computation in terms of a tree um and so + + + align:start position:0% +computation in terms of a tree um and so +here the non-deterministic computation + + align:start position:0% +here the non-deterministic computation + + + align:start position:0% +here the non-deterministic computation +tree for n on some input W so n for + + align:start position:0% +tree for n on some input W so n for + + + align:start position:0% +tree for n on some input W so n for +non-deterministic + + align:start position:0% +non-deterministic + + + align:start position:0% +non-deterministic +uh here is the tree um somewhere down + + align:start position:0% +uh here is the tree um somewhere down + + + align:start position:0% +uh here is the tree um somewhere down +here it might end up accepting and as I + + align:start position:0% +here it might end up accepting and as I + + + align:start position:0% +here it might end up accepting and as I +mentioned that is going to be uh + + align:start position:0% +mentioned that is going to be uh + + + align:start position:0% +mentioned that is going to be uh +defining the overall computation to be + + align:start position:0% +defining the overall computation to be + + + align:start position:0% +defining the overall computation to be +accepting if there is some place here + + align:start position:0% +accepting if there is some place here + + + align:start position:0% +accepting if there is some place here +that's accepting and the only way it can + + align:start position:0% +that's accepting and the only way it can + + + align:start position:0% +that's accepting and the only way it can +be non-accepting computation if there is + + align:start position:0% +be non-accepting computation if there is + + + align:start position:0% +be non-accepting computation if there is +no accept that occurs anywhere + + align:start position:0% +no accept that occurs anywhere + + + align:start position:0% +no accept that occurs anywhere +and somehow if you're going to convert + + align:start position:0% +and somehow if you're going to convert + + + align:start position:0% +and somehow if you're going to convert +this non- deterministic machine to a + + align:start position:0% +this non- deterministic machine to a + + + align:start position:0% +this non- deterministic machine to a +deterministic machine the deterministic + + align:start position:0% +deterministic machine the deterministic + + + align:start position:0% +deterministic machine the deterministic +machine is going to have to get that + + align:start position:0% +machine is going to have to get that + + + align:start position:0% +machine is going to have to get that +same effect though it only has determin + + align:start position:0% +same effect though it only has determin + + + align:start position:0% +same effect though it only has determin +you know doesn't have the + + align:start position:0% +you know doesn't have the + + + align:start position:0% +you know doesn't have the +non-determinism so how does it manage + + align:start position:0% +non-determinism so how does it manage + + + align:start position:0% +non-determinism so how does it manage +that well it's really going to be + + align:start position:0% +that well it's really going to be + + + align:start position:0% +that well it's really going to be +carrying out the simulation you know um + + align:start position:0% +carrying out the simulation you know um + + + align:start position:0% +carrying out the simulation you know um +kind of as you would imagine doing it + + align:start position:0% +kind of as you would imagine doing it + + + align:start position:0% +kind of as you would imagine doing it +yourself if you were told you had to + + align:start position:0% +yourself if you were told you had to + + + align:start position:0% +yourself if you were told you had to +simulate a non-deterministic turing + + align:start position:0% +simulate a non-deterministic turing + + + align:start position:0% +simulate a non-deterministic turing +machine which is you're going to search + + align:start position:0% +machine which is you're going to search + + + align:start position:0% +machine which is you're going to search +that tree of possibility ities looking + + align:start position:0% +that tree of possibility ities looking + + + align:start position:0% +that tree of possibility ities looking +to see if you find and accept if you do + + align:start position:0% +to see if you find and accept if you do + + + align:start position:0% +to see if you find and accept if you do +then you accept if you if you don't well + + align:start position:0% +then you accept if you if you don't well + + + align:start position:0% +then you accept if you if you don't well +maybe you'll go forever or maybe you'll + + align:start position:0% +maybe you'll go forever or maybe you'll + + + align:start position:0% +maybe you'll go forever or maybe you'll +manage to search the entire tree and + + align:start position:0% +manage to search the entire tree and + + + align:start position:0% +manage to search the entire tree and +then you will um say no I accept uh no I + + align:start position:0% +then you will um say no I accept uh no I + + + align:start position:0% +then you will um say no I accept uh no I +reject um okay so let's just see again + + align:start position:0% +reject um okay so let's just see again + + + align:start position:0% +reject um okay so let's just see again +what the data structure of that + + align:start position:0% +what the data structure of that + + + align:start position:0% +what the data structure of that +deterministic machine's tape is going to + + align:start position:0% +deterministic machine's tape is going to + + + align:start position:0% +deterministic machine's tape is going to +look like um so the way this simulation + + align:start position:0% +look like um so the way this simulation + + + align:start position:0% +look like um so the way this simulation +is going to carry out and and you know + + align:start position:0% +is going to carry out and and you know + + + align:start position:0% +is going to carry out and and you know +you could program this in a of different + + align:start position:0% +you could program this in a of different + + + align:start position:0% +you could program this in a of different +ways and in fact the textbook has a + + align:start position:0% +ways and in fact the textbook has a + + + align:start position:0% +ways and in fact the textbook has a +somewhat different simulation but I + + align:start position:0% +somewhat different simulation but I + + + align:start position:0% +somewhat different simulation but I +think this one here is uh lends itself a + + align:start position:0% +think this one here is uh lends itself a + + + align:start position:0% +think this one here is uh lends itself a +little bit better um and maybe it's a + + align:start position:0% +little bit better um and maybe it's a + + + align:start position:0% +little bit better um and maybe it's a +little simpler for description um in + + align:start position:0% +little simpler for description um in + + + align:start position:0% +little simpler for description um in +this in this setting uh but there's lots + + align:start position:0% +this in this setting uh but there's lots + + + align:start position:0% +this in this setting uh but there's lots +of different ways of improving these + + align:start position:0% +of different ways of improving these + + + align:start position:0% +of different ways of improving these +things um so we're g to m is going to + + align:start position:0% +things um so we're g to m is going to + + + align:start position:0% +things um so we're g to m is going to +simulate n kind of a little bit similar + + align:start position:0% +simulate n kind of a little bit similar + + + align:start position:0% +simulate n kind of a little bit similar +to the previous uh simulation it's going + + align:start position:0% +to the previous uh simulation it's going + + + align:start position:0% +to the previous uh simulation it's going +to break the tape up into + + align:start position:0% +to break the tape up into + + + align:start position:0% +to break the tape up into +blocks and it's going to now store in + + align:start position:0% +blocks and it's going to now store in + + + align:start position:0% +blocks and it's going to now store in +each + + align:start position:0% +each + + + align:start position:0% +each +block um a different thread at a + + align:start position:0% +block um a different thread at a + + + align:start position:0% +block um a different thread at a +particular point in time of n's + + align:start position:0% +particular point in time of n's + + + align:start position:0% +particular point in time of n's +computation so you imagine where m is + + align:start position:0% +computation so you imagine where m is + + + align:start position:0% +computation so you imagine where m is +going to be simulating n sort + + align:start position:0% +going to be simulating n sort + + + align:start position:0% +going to be simulating n sort +of um doing the same + + align:start position:0% +of um doing the same + + + align:start position:0% +of um doing the same +parallelism but doing the getting the + + align:start position:0% +parallelism but doing the getting the + + + align:start position:0% +parallelism but doing the getting the +effect of the parallelism not through + + align:start position:0% +effect of the parallelism not through + + + align:start position:0% +effect of the parallelism not through +the non-determinism but by maintaining + + align:start position:0% +the non-determinism but by maintaining + + + align:start position:0% +the non-determinism but by maintaining +cop C of each of the threads on its tape + + align:start position:0% +cop C of each of the threads on its tape + + + align:start position:0% +cop C of each of the threads on its tape +and then updating them + + align:start position:0% +and then updating them + + + align:start position:0% +and then updating them +accordingly so the idea is I think not + + align:start position:0% +accordingly so the idea is I think not + + + align:start position:0% +accordingly so the idea is I think not +not too complicated + + align:start position:0% +not too complicated + + + align:start position:0% +not too complicated +um so let's just see some of the some of + + align:start position:0% +um so let's just see some of the some of + + + align:start position:0% +um so let's just see some of the some of +the details here so here here populating + + align:start position:0% +the details here so here here populating + + + align:start position:0% +the details here so here here populating +those blocks with the contents of um + + align:start position:0% +those blocks with the contents of um + + + align:start position:0% +those blocks with the contents of um +ends tape on different threads at at a s + + align:start position:0% +ends tape on different threads at at a s + + + align:start position:0% +ends tape on different threads at at a s +you know maybe that corresponds to um + + align:start position:0% +you know maybe that corresponds to um + + + align:start position:0% +you know maybe that corresponds to um +ends tape you know after the fifth step + + align:start position:0% +ends tape you know after the fifth step + + + align:start position:0% +ends tape you know after the fifth step +of end + + align:start position:0% +of end + + + align:start position:0% +of end +um you know on each of those threads you + + align:start position:0% +um you know on each of those threads you + + + align:start position:0% +um you know on each of those threads you +have these three possibilities let's say + + align:start position:0% +have these three possibilities let's say + + + align:start position:0% +have these three possibilities let's say +written down as three different + + align:start position:0% + + + + align:start position:0% + +blocks um now + + align:start position:0% +blocks um now + + + align:start position:0% +blocks um now +uh remember in the case of the + + align:start position:0% +uh remember in the case of the + + + align:start position:0% +uh remember in the case of the +multi-tape simulation we needed to + + align:start position:0% +multi-tape simulation we needed to + + + align:start position:0% +multi-tape simulation we needed to +record some extra inform extra + + align:start position:0% +record some extra inform extra + + + align:start position:0% +record some extra inform extra +information in particular we had to + + align:start position:0% +information in particular we had to + + + align:start position:0% +information in particular we had to +record the location of the heads by + + align:start position:0% +record the location of the heads by + + + align:start position:0% +record the location of the heads by +using those dotted symbols we're going + + align:start position:0% +using those dotted symbols we're going + + + align:start position:0% +using those dotted symbols we're going +to do that again because each one of + + align:start position:0% +to do that again because each one of + + + align:start position:0% +to do that again because each one of +these threads might have their head in + + align:start position:0% +these threads might have their head in + + + align:start position:0% +these threads might have their head in +some different location but we're going + + align:start position:0% +some different location but we're going + + + align:start position:0% +some different location but we're going +to have to do more but let actually so + + align:start position:0% +to have to do more but let actually so + + + align:start position:0% +to have to do more but let actually so +let's do one one thing at a time we're + + align:start position:0% +let's do one one thing at a time we're + + + align:start position:0% +let's do one one thing at a time we're +going to store the head + + align:start position:0% +going to store the head + + + align:start position:0% +going to store the head +location here they are all written down + + align:start position:0% +location here they are all written down + + + align:start position:0% +location here they are all written down +as dotted symbols but now there's + + align:start position:0% +as dotted symbols but now there's + + + align:start position:0% +as dotted symbols but now there's +something that goes further because in + + align:start position:0% +something that goes further because in + + + align:start position:0% +something that goes further because in +the multi-tape + + align:start position:0% +the multi-tape + + + align:start position:0% +the multi-tape +case there was one Global + + align:start position:0% +case there was one Global + + + align:start position:0% +case there was one Global +state that the multi-tape machine was in + + align:start position:0% +state that the multi-tape machine was in + + + align:start position:0% +state that the multi-tape machine was in +of course at any given time it's just + + align:start position:0% +of course at any given time it's just + + + align:start position:0% +of course at any given time it's just +one has one finite control it's in one + + align:start position:0% +one has one finite control it's in one + + + align:start position:0% +one has one finite control it's in one +state um and + + align:start position:0% +state um and + + + align:start position:0% +state um and +uh but but but in the case of the + + align:start position:0% +uh but but but in the case of the + + + align:start position:0% +uh but but but in the case of the +non-deterministic machine that we're + + align:start position:0% +non-deterministic machine that we're + + + align:start position:0% +non-deterministic machine that we're +simulating now each thread can be in a + + align:start position:0% +simulating now each thread can be in a + + + align:start position:0% +simulating now each thread can be in a +different + + align:start position:0% +different + + + align:start position:0% +different +state um so whereas before we could keep + + align:start position:0% +state um so whereas before we could keep + + + align:start position:0% +state um so whereas before we could keep +track of the multi tapes tur the + + align:start position:0% +track of the multi tapes tur the + + + align:start position:0% +track of the multi tapes tur the +multitape machine State inside the + + align:start position:0% +multitape machine State inside the + + + align:start position:0% +multitape machine State inside the +single tape machine's finite control now + + align:start position:0% +single tape machine's finite control now + + + align:start position:0% +single tape machine's finite control now +there could be many many different + + align:start position:0% +there could be many many different + + + align:start position:0% +there could be many many different +states to keep track of so you won't be + + align:start position:0% +states to keep track of so you won't be + + + align:start position:0% +states to keep track of so you won't be +able to store that in a finite control + + align:start position:0% +able to store that in a finite control + + + align:start position:0% +able to store that in a finite control +anymore because there could be some huge + + align:start position:0% +anymore because there could be some huge + + + align:start position:0% +anymore because there could be some huge +number of threads active at any given + + align:start position:0% +number of threads active at any given + + + align:start position:0% +number of threads active at any given +stage and some of them can be in one + + align:start position:0% +stage and some of them can be in one + + + align:start position:0% +stage and some of them can be in one +state others can be in different state + + align:start position:0% +state others can be in different state + + + align:start position:0% +state others can be in different state +and you know how do you keep track of + + align:start position:0% +and you know how do you keep track of + + + align:start position:0% +and you know how do you keep track of +all that so we're going to have to use + + align:start position:0% +all that so we're going to have to use + + + align:start position:0% +all that so we're going to have to use +the tape we're going to actually write + + align:start position:0% +the tape we're going to actually write + + + align:start position:0% +the tape we're going to actually write +down which state a given thread is in on + + align:start position:0% +down which state a given thread is in on + + + align:start position:0% +down which state a given thread is in on +that block and we'll do that I'll show + + align:start position:0% +that block and we'll do that I'll show + + + align:start position:0% +that block and we'll do that I'll show +it like this um so writing down the + + align:start position:0% +it like this um so writing down the + + + align:start position:0% +it like this um so writing down the +state of each in the + + align:start position:0% +state of each in the + + + align:start position:0% +state of each in the +block by writing down symbols which + + align:start position:0% +block by writing down symbols which + + + align:start position:0% +block by writing down symbols which +correspond to those uh + + align:start position:0% +correspond to those uh + + + align:start position:0% +correspond to those uh +States so we're actually in a sense + + align:start position:0% +States so we're actually in a sense + + + align:start position:0% +States so we're actually in a sense +writing the state down right on top of + + align:start position:0% +writing the state down right on top of + + + align:start position:0% +writing the state down right on top of +the block using symbols that correspond + + align:start position:0% +the block using symbols that correspond + + + align:start position:0% +the block using symbols that correspond +to those States so again we're doing + + align:start position:0% +to those States so again we're doing + + + align:start position:0% +to those States so again we're doing +getting that effect by increasing the + + align:start position:0% +getting that effect by increasing the + + + align:start position:0% +getting that effect by increasing the +tape alphabet of M to + + align:start position:0% +tape alphabet of M to + + + align:start position:0% +tape alphabet of M to +include um symbols that correspond to + + align:start position:0% +include um symbols that correspond to + + + align:start position:0% +include um symbols that correspond to +each of its + + align:start position:0% +each of its + + + align:start position:0% +each of its +states and we're going to write those + + align:start position:0% +states and we're going to write those + + + align:start position:0% +states and we're going to write those +symbols down so here's the symbol for + + align:start position:0% +symbols down so here's the symbol for + + + align:start position:0% +symbols down so here's the symbol for +State Q8 that says well one of that very + + align:start position:0% +State Q8 that says well one of that very + + + align:start position:0% +State Q8 that says well one of that very +first thread of n's computation is in + + align:start position:0% +first thread of n's computation is in + + + align:start position:0% +first thread of n's computation is in +state Q8 it's in this third position of + + align:start position:0% +state Q8 it's in this third position of + + + align:start position:0% +state Q8 it's in this third position of +its t um on its tape uh the head is on + + align:start position:0% +its t um on its tape uh the head is on + + + align:start position:0% +its t um on its tape uh the head is on +the third position there and the tape + + align:start position:0% +the third position there and the tape + + + align:start position:0% +the third position there and the tape +contents is + + align:start position:0% +contents is + + + align:start position:0% +contents is +aaba that's how we represent that thread + + align:start position:0% +aaba that's how we represent that thread + + + align:start position:0% +aaba that's how we represent that thread +of the + + align:start position:0% +of the + + + align:start position:0% +of the +computation um including the + + align:start position:0% +computation um including the + + + align:start position:0% +computation um including the +state okay now um so am is going to + + align:start position:0% +state okay now um so am is going to + + + align:start position:0% +state okay now um so am is going to +carry out that step by step maintaining + + align:start position:0% +carry out that step by step maintaining + + + align:start position:0% +carry out that step by step maintaining +that information on its tape they're + + align:start position:0% +that information on its tape they're + + + align:start position:0% +that information on its tape they're +again similar to before there might be + + align:start position:0% +again similar to before there might be + + + align:start position:0% +again similar to before there might be +some special situations arising so for + + align:start position:0% +some special situations arising so for + + + align:start position:0% +some special situations arising so for +example n is not non-deterministic so a + + align:start position:0% +example n is not non-deterministic so a + + + align:start position:0% +example n is not non-deterministic so a +rad might Fork into uh two threads what + + align:start position:0% +rad might Fork into uh two threads what + + + align:start position:0% +rad might Fork into uh two threads what +do we do then um well sort of + + align:start position:0% +do we do then um well sort of + + + align:start position:0% +do we do then um well sort of +the you know the reasonable thing if + + align:start position:0% +the you know the reasonable thing if + + + align:start position:0% +the you know the reasonable thing if +there's a forking thread M then copies + + align:start position:0% +there's a forking thread M then copies + + + align:start position:0% +there's a forking thread M then copies +that block makes two copies of the block + + align:start position:0% +that block makes two copies of the block + + + align:start position:0% +that block makes two copies of the block +to correspond to the two or however many + + align:start position:0% +to correspond to the two or however many + + + align:start position:0% +to correspond to the two or however many +copies you need to correspond to the + + align:start position:0% +copies you need to correspond to the + + + align:start position:0% +copies you need to correspond to the +possibilities that um that that thread + + align:start position:0% +possibilities that um that that thread + + + align:start position:0% +possibilities that um that that thread +is branching into so you want to + + align:start position:0% +is branching into so you want to + + + align:start position:0% +is branching into so you want to +represent them all on different blocks + + align:start position:0% +represent them all on different blocks + + + align:start position:0% +represent them all on different blocks +of M's tape + + align:start position:0% +of M's tape + + + align:start position:0% +of M's tape +all right um and then if M ever finds + + align:start position:0% +all right um and then if M ever finds + + + align:start position:0% +all right um and then if M ever finds +out that on one of the threads it's + + align:start position:0% +out that on one of the threads it's + + + align:start position:0% +out that on one of the threads it's +entering the accept state it can just + + align:start position:0% +entering the accept state it can just + + + align:start position:0% +entering the accept state it can just +shut down the whole computation at that + + align:start position:0% +shut down the whole computation at that + + + align:start position:0% +shut down the whole computation at that +point and say + + align:start position:0% + + + + align:start position:0% + +accept Okay so perhaps a little + + align:start position:0% +accept Okay so perhaps a little + + + align:start position:0% +accept Okay so perhaps a little +elaborate but I think conceptually + + align:start position:0% +elaborate but I think conceptually + + + align:start position:0% +elaborate but I think conceptually +hopefully um not too bad um now uh uh + + align:start position:0% +hopefully um not too bad um now uh uh + + + align:start position:0% +hopefully um not too bad um now uh uh +let's move on then to talk about uh + + align:start position:0% +let's move on then to talk about uh + + + align:start position:0% +let's move on then to talk about uh +somewhat of a different uh looking well + + align:start position:0% +somewhat of a different uh looking well + + + align:start position:0% +somewhat of a different uh looking well +sort of a different model in a way um uh + + align:start position:0% +sort of a different model in a way um uh + + + align:start position:0% +sort of a different model in a way um uh +which has some historical significance + + align:start position:0% +which has some historical significance + + + align:start position:0% +which has some historical significance +and sometimes is a helpful way to look + + align:start position:0% +and sometimes is a helpful way to look + + + align:start position:0% +and sometimes is a helpful way to look +at uh touring recognizability and you + + align:start position:0% +at uh touring recognizability and you + + + align:start position:0% +at uh touring recognizability and you +and incidentally you have a homework + + align:start position:0% +and incidentally you have a homework + + + align:start position:0% +and incidentally you have a homework +problem uh on this um model called an + + align:start position:0% +problem uh on this um model called an + + + align:start position:0% +problem uh on this um model called an +enumerator or Turing + + align:start position:0% +enumerator or Turing + + + align:start position:0% +enumerator or Turing +enumerator um + + align:start position:0% +enumerator um + + + align:start position:0% +enumerator um +so uh here uh it's going to operate some + + align:start position:0% +so uh here uh it's going to operate some + + + align:start position:0% +so uh here uh it's going to operate some +much differently um first of all we're + + align:start position:0% +much differently um first of all we're + + + align:start position:0% +much differently um first of all we're +going to enhance the touring Machine + + align:start position:0% +going to enhance the touring Machine + + + align:start position:0% +going to enhance the touring Machine +model it's going to now have just a + + align:start position:0% +model it's going to now have just a + + + align:start position:0% +model it's going to now have just a +single tape but it's going to also have + + align:start position:0% +single tape but it's going to also have + + + align:start position:0% +single tape but it's going to also have +a + + align:start position:0% +a + + + align:start position:0% +a +printer okay so we're now adding in this + + align:start position:0% +printer okay so we're now adding in this + + + align:start position:0% +printer okay so we're now adding in this +new device into the touring machine + + align:start position:0% +new device into the touring machine + + + align:start position:0% +new device into the touring machine +called the printer um and + + align:start position:0% +called the printer um and + + + align:start position:0% +called the printer um and +um the touring machine has uh tape as + + align:start position:0% +um the touring machine has uh tape as + + + align:start position:0% +um the touring machine has uh tape as +before except we never provide any input + + align:start position:0% +before except we never provide any input + + + align:start position:0% +before except we never provide any input +to the machine + + align:start position:0% +to the machine + + + align:start position:0% +to the machine +um the tape always starts out fully + + align:start position:0% +um the tape always starts out fully + + + align:start position:0% +um the tape always starts out fully +blank it's only used for reading and + + align:start position:0% +blank it's only used for reading and + + + align:start position:0% +blank it's only used for reading and +writing uh only used for for like the + + align:start position:0% +writing uh only used for for like the + + + align:start position:0% +writing uh only used for for like the +keeping TR for uh for for work um it's + + align:start position:0% +keeping TR for uh for for work um it's + + + align:start position:0% +keeping TR for uh for for work um it's +not where you present the input so how + + align:start position:0% +not where you present the input so how + + + align:start position:0% +not where you present the input so how +do you talk about the language of the + + align:start position:0% +do you talk about the language of the + + + align:start position:0% +do you talk about the language of the +machine well what the way you work this + + align:start position:0% +machine well what the way you work this + + + align:start position:0% +machine well what the way you work this +machine is you take this enumerator uh + + align:start position:0% +machine is you take this enumerator uh + + + align:start position:0% +machine is you take this enumerator uh +it's a deterministic Mach with a printer + + align:start position:0% +it's a deterministic Mach with a printer + + + align:start position:0% +it's a deterministic Mach with a printer +as I mentioned you start it off in blank + + align:start position:0% +as I mentioned you start it off in blank + + + align:start position:0% +as I mentioned you start it off in blank +tape and it you it runs and runs and + + align:start position:0% +tape and it you it runs and runs and + + + align:start position:0% +tape and it you it runs and runs and +runs and periodically it can print a + + align:start position:0% +runs and periodically it can print a + + + align:start position:0% +runs and periodically it can print a +string Under some sort of program + + align:start position:0% +string Under some sort of program + + + align:start position:0% +string Under some sort of program +control which I'm not going to spell out + + align:start position:0% +control which I'm not going to spell out + + + align:start position:0% +control which I'm not going to spell out +for you but you can imagine you might + + align:start position:0% +for you but you can imagine you might + + + align:start position:0% +for you but you can imagine you might +have to define the machine in such a way + + align:start position:0% +have to define the machine in such a way + + + align:start position:0% +have to define the machine in such a way +that when it goes into a certain print + + align:start position:0% +that when it goes into a certain print + + + align:start position:0% +that when it goes into a certain print +state so we're not going to set that all + + align:start position:0% +state so we're not going to set that all + + + align:start position:0% +state so we're not going to set that all +up then whatever string is in a certain + + align:start position:0% +up then whatever string is in a certain + + + align:start position:0% +up then whatever string is in a certain +region of the tape maybe from the the + + align:start position:0% +region of the tape maybe from the the + + + align:start position:0% +region of the tape maybe from the the +start point up to the head location that + + align:start position:0% +start point up to the head location that + + + align:start position:0% +start point up to the head location that +gets printed out on the printer and then + + align:start position:0% +gets printed out on the printer and then + + + align:start position:0% +gets printed out on the printer and then +it can print out other strings in due + + align:start position:0% +it can print out other strings in due + + + align:start position:0% +it can print out other strings in due +course and so periodically you think of + + align:start position:0% +course and so periodically you think of + + + align:start position:0% +course and so periodically you think of +this printer as printing out a string um + + align:start position:0% +this printer as printing out a string um + + + align:start position:0% +this printer as printing out a string um +under the control of the uh the turing + + align:start position:0% +under the control of the uh the turing + + + align:start position:0% +under the control of the uh the turing +machine enumerator um and so these print + + align:start position:0% +machine enumerator um and so these print + + + align:start position:0% +machine enumerator um and so these print +strings these strings it could print out + + align:start position:0% +strings these strings it could print out + + + align:start position:0% +strings these strings it could print out +W1 W2 they + + align:start position:0% +W1 W2 they + + + align:start position:0% +W1 W2 they +appear and uh the machine might possibly + + align:start position:0% +appear and uh the machine might possibly + + + align:start position:0% +appear and uh the machine might possibly +go forever and print infinitely many + + align:start position:0% +go forever and print infinitely many + + + align:start position:0% +go forever and print infinitely many +strings or it might uh go forever and + + align:start position:0% +strings or it might uh go forever and + + + align:start position:0% +strings or it might uh go forever and +only print finally many strings or it + + align:start position:0% +only print finally many strings or it + + + align:start position:0% +only print finally many strings or it +might stop after a while by entering a a + + align:start position:0% +might stop after a while by entering a a + + + align:start position:0% +might stop after a while by entering a a +halting state accepting and rejecting is + + align:start position:0% +halting state accepting and rejecting is + + + align:start position:0% +halting state accepting and rejecting is +irrelevant but enters a halting state + + align:start position:0% +irrelevant but enters a halting state + + + align:start position:0% +irrelevant but enters a halting state +and then U the number the strings that + + align:start position:0% +and then U the number the strings that + + + align:start position:0% +and then U the number the strings that +it's printed out the finitely many + + align:start position:0% +it's printed out the finitely many + + + align:start position:0% +it's printed out the finitely many +strings are printed out or just that's + + align:start position:0% +strings are printed out or just that's + + + align:start position:0% +strings are printed out or just that's +the output of the machine now the + + align:start position:0% +the output of the machine now the + + + align:start position:0% +the output of the machine now the +language of the machine is the + + align:start position:0% +language of the machine is the + + + align:start position:0% +language of the machine is the +collection of all strings that it ever + + align:start position:0% +collection of all strings that it ever + + + align:start position:0% +collection of all strings that it ever +prints + + align:start position:0% + + + + align:start position:0% + +out so we're defining language in a + + align:start position:0% +out so we're defining language in a + + + align:start position:0% +out so we're defining language in a +somewhat different way here it's not the + + align:start position:0% +somewhat different way here it's not the + + + align:start position:0% +somewhat different way here it's not the +strings that it accepts it's the strings + + align:start position:0% +strings that it accepts it's the strings + + + align:start position:0% +strings that it accepts it's the strings +that it + + align:start position:0% +that it + + + align:start position:0% +that it +prints so we think of this mean Sheen + + align:start position:0% +prints so we think of this mean Sheen + + + align:start position:0% +prints so we think of this mean Sheen +almost a little bit analogous to like + + align:start position:0% +almost a little bit analogous to like + + + align:start position:0% +almost a little bit analogous to like +the regular expression or the grammar in + + align:start position:0% +the regular expression or the grammar in + + + align:start position:0% +the regular expression or the grammar in +the sense that it's a generative model + + align:start position:0% +the sense that it's a generative model + + + align:start position:0% +the sense that it's a generative model +it produces the language rather than + + align:start position:0% +it produces the language rather than + + + align:start position:0% +it produces the language rather than +accepts the strings in the + + align:start position:0% + + + + align:start position:0% + +language so it's not really a recognizer + + align:start position:0% +language so it's not really a recognizer + + + align:start position:0% +language so it's not really a recognizer +it's a generator and the language of the + + align:start position:0% +it's a generator and the language of the + + + align:start position:0% +it's a generator and the language of the +machine as I'm writing over here for + + align:start position:0% +machine as I'm writing over here for + + + align:start position:0% +machine as I'm writing over here for +enumerator here we say that its language + + align:start position:0% +enumerator here we say that its language + + + align:start position:0% +enumerator here we say that its language +is a collection of strings at it + + align:start position:0% +is a collection of strings at it + + + align:start position:0% +is a collection of strings at it +prints okay now we will show that a + + align:start position:0% +prints okay now we will show that a + + + align:start position:0% +prints okay now we will show that a +language is touring recognizable in the + + align:start position:0% +language is touring recognizable in the + + + align:start position:0% +language is touring recognizable in the +previous sense you know you recognized + + align:start position:0% +previous sense you know you recognized + + + align:start position:0% +previous sense you know you recognized +by some ordinary touring machine if only + + align:start position:0% +by some ordinary touring machine if only + + + align:start position:0% +by some ordinary touring machine if only +if it's the language of some + + align:start position:0% +if it's the language of some + + + align:start position:0% +if it's the language of some +enumerate and actually this is kind of a + + align:start position:0% +enumerate and actually this is kind of a + + + align:start position:0% +enumerate and actually this is kind of a +little bit of an interesting proof uh + + align:start position:0% +little bit of an interesting proof uh + + + align:start position:0% +little bit of an interesting proof uh +you have to do some work it's an if and + + align:start position:0% +you have to do some work it's an if and + + + align:start position:0% +you have to do some work it's an if and +only if now neither direction is + + align:start position:0% +only if now neither direction is + + + align:start position:0% +only if now neither direction is +immediate you're going to have to do + + align:start position:0% +immediate you're going to have to do + + + align:start position:0% +immediate you're going to have to do +some work uh in both directions One + + align:start position:0% +some work uh in both directions One + + + align:start position:0% +some work uh in both directions One +Direction is a little harder then the + + align:start position:0% +Direction is a little harder then the + + + align:start position:0% +Direction is a little harder then the +other will start off with the easier + + align:start position:0% +other will start off with the easier + + + align:start position:0% +other will start off with the easier +Direction let's say we have an + + align:start position:0% +Direction let's say we have an + + + align:start position:0% +Direction let's say we have an +enumerator + + align:start position:0% + + + + align:start position:0% + +hope you hopefully you got this concept + + align:start position:0% +hope you hopefully you got this concept + + + align:start position:0% +hope you hopefully you got this concept +of this touring machine which + + align:start position:0% +of this touring machine which + + + align:start position:0% +of this touring machine which +periodically P prints strings when + + align:start position:0% +periodically P prints strings when + + + align:start position:0% +periodically P prints strings when +you've started it off on the empty tape + + align:start position:0% +you've started it off on the empty tape + + + align:start position:0% +you've started it off on the empty tape +um uh so now what I'm going to construct + + align:start position:0% +um uh so now what I'm going to construct + + + align:start position:0% +um uh so now what I'm going to construct +for you um is the touring machine + + align:start position:0% +for you um is the touring machine + + + align:start position:0% +for you um is the touring machine +recognizer defined from the enumerator + + align:start position:0% +recognizer defined from the enumerator + + + align:start position:0% +recognizer defined from the enumerator +so this recognizer is going to be + + align:start position:0% +so this recognizer is going to be + + + align:start position:0% +so this recognizer is going to be +simulating the + + align:start position:0% +simulating the + + + align:start position:0% +simulating the +enumerator um so it's basically the + + align:start position:0% +enumerator um so it's basically the + + + align:start position:0% +enumerator um so it's basically the +recognizer you're going to launch the + + align:start position:0% +recognizer you're going to launch the + + + align:start position:0% +recognizer you're going to launch the +enumerator it's going to start off + + align:start position:0% +enumerator it's going to start off + + + align:start position:0% +enumerator it's going to start off +simulating it + + align:start position:0% +simulating it + + + align:start position:0% +simulating it +um now if you want if it's convenient we + + align:start position:0% +um now if you want if it's convenient we + + + align:start position:0% +um now if you want if it's convenient we +we could use several tapes we can use + + align:start position:0% +we could use several tapes we can use + + + align:start position:0% +we could use several tapes we can use +one tape to simulate the recognizer and + + align:start position:0% +one tape to simulate the recognizer and + + + align:start position:0% +one tape to simulate the recognizer and +you have other tapes available for + + align:start position:0% +you have other tapes available for + + + align:start position:0% +you have other tapes available for +convenience if you want because we + + align:start position:0% +convenience if you want because we + + + align:start position:0% +convenience if you want because we +already showed multi-tape and single + + align:start position:0% +already showed multi-tape and single + + + align:start position:0% +already showed multi-tape and single +tape are equivalent so if you want to + + align:start position:0% +tape are equivalent so if you want to + + + align:start position:0% +tape are equivalent so if you want to +think of M as having multiple tapes it's + + align:start position:0% +think of M as having multiple tapes it's + + + align:start position:0% +think of M as having multiple tapes it's +not going to really be that important + + align:start position:0% +not going to really be that important + + + align:start position:0% +not going to really be that important +relevant to my conversation um but + + align:start position:0% +relevant to my conversation um but + + + align:start position:0% +relevant to my conversation um but +you're going to simulate e starting on + + align:start position:0% +you're going to simulate e starting on + + + align:start position:0% +you're going to simulate e starting on +the blank input as you're supposed to + + align:start position:0% +the blank input as you're supposed to + + + align:start position:0% +the blank input as you're supposed to +and then you're going to see whenever e + + align:start position:0% +and then you're going to see whenever e + + + align:start position:0% +and then you're going to see whenever e +prints an X you're going to see if x is + + align:start position:0% +prints an X you're going to see if x is + + + align:start position:0% +prints an X you're going to see if x is +the same as the input to the + + align:start position:0% +the same as the input to the + + + align:start position:0% +the same as the input to the +recognizer you you get the idea so we + + align:start position:0% +recognizer you you get the idea so we + + + align:start position:0% +recognizer you you get the idea so we +have a recognizer it has an input string + + align:start position:0% +have a recognizer it has an input string + + + align:start position:0% +have a recognizer it has an input string +maybe like one + + align:start position:0% +maybe like one + + + align:start position:0% +maybe like one +one01 and I want to know I want to + + align:start position:0% +one01 and I want to know I want to + + + align:start position:0% +one01 and I want to know I want to +accept that string if it's one of the + + align:start position:0% +accept that string if it's one of the + + + align:start position:0% +accept that string if it's one of the +strings that the enumerator e prints out + + align:start position:0% +strings that the enumerator e prints out + + + align:start position:0% +strings that the enumerator e prints out +because that's what the recognizer do + + align:start position:0% +because that's what the recognizer do + + + align:start position:0% +because that's what the recognizer do +it's supposed to accept all the strings + + align:start position:0% +it's supposed to accept all the strings + + + align:start position:0% +it's supposed to accept all the strings +that the enumerator prints out so I got + + align:start position:0% +that the enumerator prints out so I got + + + align:start position:0% +that the enumerator prints out so I got +this one one 01 what do I do I launch I + + align:start position:0% +this one one 01 what do I do I launch I + + + align:start position:0% +this one one 01 what do I do I launch I +fire up that numerator I get it going + + align:start position:0% +fire up that numerator I get it going + + + align:start position:0% +fire up that numerator I get it going +and I start watching the strings that + + align:start position:0% +and I start watching the strings that + + + align:start position:0% +and I start watching the strings that +prints out comparing them with my input + + align:start position:0% +prints out comparing them with my input + + + align:start position:0% +prints out comparing them with my input +string + + align:start position:0% +string + + + align:start position:0% +string +1101 if I ever see it print out a + + align:start position:0% +1101 if I ever see it print out a + + + align:start position:0% +1101 if I ever see it print out a + + align:start position:0% + + + align:start position:0% +great I I know I can accept because I + + align:start position:0% +great I I know I can accept because I + + + align:start position:0% +great I I know I can accept because I +know it's in the enumerator + + align:start position:0% +know it's in the enumerator + + + align:start position:0% +know it's in the enumerator +language but if I compare and compare + + align:start position:0% +language but if I compare and compare + + + align:start position:0% +language but if I compare and compare +and compare I never see uh the + + align:start position:0% +and compare I never see uh the + + + align:start position:0% +and compare I never see uh the +enumerator ever printing out uh my input + + align:start position:0% +enumerator ever printing out uh my input + + + align:start position:0% +enumerator ever printing out uh my input +string 1101 uh well I just keep + + align:start position:0% +string 1101 uh well I just keep + + + align:start position:0% +string 1101 uh well I just keep +simulating e if e holds well then I can + + align:start position:0% +simulating e if e holds well then I can + + + align:start position:0% +simulating e if e holds well then I can +hold and reject um if I've never seen + + align:start position:0% +hold and reject um if I've never seen + + + align:start position:0% +hold and reject um if I've never seen +that string coming out as an output um + + align:start position:0% +that string coming out as an output um + + + align:start position:0% +that string coming out as an output um +if e doesn't hold well I'm just not + + align:start position:0% +if e doesn't hold well I'm just not + + + align:start position:0% +if e doesn't hold well I'm just not +going to holdt either I'm going to go + + align:start position:0% +going to holdt either I'm going to go + + + align:start position:0% +going to holdt either I'm going to go +forever but then I'm going to be + + align:start position:0% +forever but then I'm going to be + + + align:start position:0% +forever but then I'm going to be +rejecting my input by + + align:start position:0% +rejecting my input by + + + align:start position:0% +rejecting my input by +looping okay so that's the proof of + + align:start position:0% +looping okay so that's the proof of + + + align:start position:0% +looping okay so that's the proof of +converting in this uh backward Direction + + align:start position:0% +converting in this uh backward Direction + + + align:start position:0% +converting in this uh backward Direction +which is the easier Direction now let's + + align:start position:0% +which is the easier Direction now let's + + + align:start position:0% +which is the easier Direction now let's +look at the forward Direction which has + + align:start position:0% +look at the forward Direction which has + + + align:start position:0% +look at the forward Direction which has +a certain wrinkle that in it that we're + + align:start position:0% +a certain wrinkle that in it that we're + + + align:start position:0% +a certain wrinkle that in it that we're +going to have to get + + align:start position:0% +going to have to get + + + align:start position:0% +going to have to get +to so now we're going to be building our + + align:start position:0% +to so now we're going to be building our + + + align:start position:0% +to so now we're going to be building our +enumerator to simulate our + + align:start position:0% +enumerator to simulate our + + + align:start position:0% +enumerator to simulate our +recognizer okay and the way we'll do + + align:start position:0% +recognizer okay and the way we'll do + + + align:start position:0% +recognizer okay and the way we'll do +that is the enumerator has to print out + + align:start position:0% +that is the enumerator has to print out + + + align:start position:0% +that is the enumerator has to print out +all of the strings that the recognizer + + align:start position:0% +all of the strings that the recognizer + + + align:start position:0% +all of the strings that the recognizer +would ever + + align:start position:0% +would ever + + + align:start position:0% +would ever +accept so you can to do the obvious + + align:start position:0% +accept so you can to do the obvious + + + align:start position:0% +accept so you can to do the obvious +thing you're going to take the + + align:start position:0% +thing you're going to take the + + + align:start position:0% +thing you're going to take the +enumerator is going to start simulating + + align:start position:0% +enumerator is going to start simulating + + + align:start position:0% +enumerator is going to start simulating +the recognizer M on all possible strings + + align:start position:0% +the recognizer M on all possible strings + + + align:start position:0% +the recognizer M on all possible strings +sort of you know one by one using doing + + align:start position:0% +sort of you know one by one using doing + + + align:start position:0% +sort of you know one by one using doing +them in parallel taking turns you never + + align:start position:0% +them in parallel taking turns you never + + + align:start position:0% +them in parallel taking turns you never +not you know we um maybe we didn't make + + align:start position:0% +not you know we um maybe we didn't make + + + align:start position:0% +not you know we um maybe we didn't make +this so explicit but you don't have you + + align:start position:0% +this so explicit but you don't have you + + + align:start position:0% +this so explicit but you don't have you +know you can sort of time share among + + align:start position:0% +know you can sort of time share among + + + align:start position:0% +know you can sort of time share among +several different possibilities you run + + align:start position:0% +several different possibilities you run + + + align:start position:0% +several different possibilities you run +you know sort of like having different + + align:start position:0% +you know sort of like having different + + + align:start position:0% +you know sort of like having different +blocks uh for the machine diff you're + + align:start position:0% +blocks uh for the machine diff you're + + + align:start position:0% +blocks uh for the machine diff you're +going to run + + align:start position:0% +going to run + + + align:start position:0% +going to run +um uh the enumerator is going to run the + + align:start position:0% +um uh the enumerator is going to run the + + + align:start position:0% +um uh the enumerator is going to run the +recognizer on um it's you know well + + align:start position:0% +recognizer on um it's you know well + + + align:start position:0% +recognizer on um it's you know well +let's just say it does it sequentially + + align:start position:0% +let's just say it does it sequentially + + + align:start position:0% +let's just say it does it sequentially +it runs it on the empty string it runs + + align:start position:0% +it runs it on the empty string it runs + + + align:start position:0% +it runs it on the empty string it runs +it on the string zero it runs it on the + + align:start position:0% +it on the string zero it runs it on the + + + align:start position:0% +it on the string zero it runs it on the +string one one runs it on the string 0 0 + + align:start position:0% +string one one runs it on the string 0 0 + + + align:start position:0% +string one one runs it on the string 0 0 +these are all the possible strings in + + align:start position:0% +these are all the possible strings in + + + align:start position:0% +these are all the possible strings in +Sigma star you you run on all of them + + align:start position:0% +Sigma star you you run on all of them + + + align:start position:0% +Sigma star you you run on all of them +and uh whenever the + + align:start position:0% +and uh whenever the + + + align:start position:0% +and uh whenever the +enumerator + + align:start position:0% +enumerator + + + align:start position:0% +enumerator +uh uh + + align:start position:0% +uh uh + + + align:start position:0% +uh uh +oh this is wrong + + align:start position:0% +oh this is wrong + + + align:start position:0% +oh this is wrong +whenever + + align:start position:0% + + + + align:start position:0% + +um so whenever + + align:start position:0% + + + + align:start position:0% + +uh M + + align:start position:0% + + + + align:start position:0% + +accepts then print I can't right very + + align:start position:0% +accepts then print I can't right very + + + align:start position:0% +accepts then print I can't right very +well + + align:start position:0% +well + + + align:start position:0% +well +print + + align:start position:0% + + + + align:start position:0% + +W um wi + + align:start position:0% + + + + align:start position:0% + +oops okay so I'm going just say it in + + align:start position:0% +oops okay so I'm going just say it in + + + align:start position:0% +oops okay so I'm going just say it in +words you're going to simulate Emma on + + align:start position:0% +words you're going to simulate Emma on + + + align:start position:0% +words you're going to simulate Emma on +hwi whenever you notice and accepting wi + + align:start position:0% +hwi whenever you notice and accepting wi + + + align:start position:0% +hwi whenever you notice and accepting wi +you just print out + + align:start position:0% +you just print out + + + align:start position:0% +you just print out +wi um because you want to print out all + + align:start position:0% +wi um because you want to print out all + + + align:start position:0% +wi um because you want to print out all +of the strings that M + + align:start position:0% +of the strings that M + + + align:start position:0% +of the strings that M +accepts now what H the pro there is a + + align:start position:0% +accepts now what H the pro there is a + + + align:start position:0% +accepts now what H the pro there is a +problem here so hopefully you're not + + align:start position:0% +problem here so hopefully you're not + + + align:start position:0% +problem here so hopefully you're not +confused by this typo + + align:start position:0% +confused by this typo + + + align:start position:0% +confused by this typo +um uh doing it sequentially like I just + + align:start position:0% +um uh doing it sequentially like I just + + + align:start position:0% +um uh doing it sequentially like I just +described doesn't quite work so let me + + align:start position:0% +described doesn't quite work so let me + + + align:start position:0% +described doesn't quite work so let me +just back that up here doing it + + align:start position:0% +just back that up here doing it + + + align:start position:0% +just back that up here doing it +sequentially doesn't quite work because + + align:start position:0% +sequentially doesn't quite work because + + + align:start position:0% +sequentially doesn't quite work because +Emma might get stuck looping on one of + + align:start position:0% +Emma might get stuck looping on one of + + + align:start position:0% +Emma might get stuck looping on one of +the wi like you know maybe when I feed W + + align:start position:0% +the wi like you know maybe when I feed W + + + align:start position:0% +the wi like you know maybe when I feed W +zero into W into m m goes + + align:start position:0% +zero into W into m m goes + + + align:start position:0% +zero into W into m m goes +forever because m is rejecting the Zero + + align:start position:0% +forever because m is rejecting the Zero + + + align:start position:0% +forever because m is rejecting the Zero +by looping but maybe it also accepts one + + align:start position:0% +by looping but maybe it also accepts one + + + align:start position:0% +by looping but maybe it also accepts one +this next string in the list the string + + align:start position:0% +this next string in the list the string + + + align:start position:0% +this next string in the list the string +one I'll never get to one by just + + align:start position:0% +one I'll never get to one by just + + + align:start position:0% +one I'll never get to one by just +feeding the strings into m one by one + + align:start position:0% +feeding the strings into m one by one + + + align:start position:0% +feeding the strings into m one by one +like this what I really have to do is + + align:start position:0% +like this what I really have to do is + + + align:start position:0% +like this what I really have to do is +run all of the strings in m in + + align:start position:0% +run all of the strings in m in + + + align:start position:0% +run all of the strings in m in +parallel and the way I'm going to + + align:start position:0% +parallel and the way I'm going to + + + align:start position:0% +parallel and the way I'm going to +indicate that is I'm going to simulate M + + align:start position:0% +indicate that is I'm going to simulate M + + + align:start position:0% +indicate that is I'm going to simulate M +on W1 to Wi for I steps for each + + align:start position:0% +on W1 to Wi for I steps for each + + + align:start position:0% +on W1 to Wi for I steps for each +possible I so I'm going to run + + align:start position:0% +possible I so I'm going to run + + + align:start position:0% +possible I so I'm going to run +M + + align:start position:0% +M + + + align:start position:0% +M +on uh more and more strings for more and + + align:start position:0% +on uh more and more strings for more and + + + align:start position:0% +on uh more and more strings for more and +more + + align:start position:0% + + + + align:start position:0% + +steps okay until and every time I notice + + align:start position:0% +steps okay until and every time I notice + + + align:start position:0% +steps okay until and every time I notice +an mxf something I print it + + align:start position:0% + + + + align:start position:0% + +out + + align:start position:0% +out + + + align:start position:0% +out +um uh + + align:start position:0% +um uh + + + align:start position:0% +um uh +so I will fix this in the um version of + + align:start position:0% +so I will fix this in the um version of + + + align:start position:0% +so I will fix this in the um version of +the uh file that I um published on the + + align:start position:0% +the uh file that I um published on the + + + align:start position:0% +the uh file that I um published on the +website so if you're still not getting + + align:start position:0% +website so if you're still not getting + + + align:start position:0% +website so if you're still not getting +it you can look there um uh but just to + + align:start position:0% +it you can look there um uh but just to + + + align:start position:0% +it you can look there um uh but just to +make things even worse I have a check in + + align:start position:0% +make things even worse I have a check in + + + align:start position:0% +make things even worse I have a check in +which is going to be about this one + + align:start position:0% +which is going to be about this one + + + align:start position:0% +which is going to be about this one +little Point here um so I got a question + + align:start position:0% +little Point here um so I got a question + + + align:start position:0% +little Point here um so I got a question +where do we get the wi strings the wi + + align:start position:0% +where do we get the wi strings the wi + + + align:start position:0% +where do we get the wi strings the wi +strings are simply the list of all + + align:start position:0% +strings are simply the list of all + + + align:start position:0% +strings are simply the list of all +strings in Sigma + + align:start position:0% +strings in Sigma + + + align:start position:0% +strings in Sigma +star so we can under program control + + align:start position:0% +star so we can under program control + + + align:start position:0% +star so we can under program control +we can make M go through every possible + + align:start position:0% +we can make M go through every possible + + + align:start position:0% +we can make M go through every possible +string like if you had an odometer + + align:start position:0% +string like if you had an odometer + + + align:start position:0% +string like if you had an odometer +you're going to first get to the empty + + align:start position:0% +you're going to first get to the empty + + + align:start position:0% +you're going to first get to the empty +string then you go to the string zero + + align:start position:0% +string then you go to the string zero + + + align:start position:0% +string then you go to the string zero +then the string one you can write a + + align:start position:0% +then the string one you can write a + + + align:start position:0% +then the string one you can write a +program which is going to do that um uh + + align:start position:0% +program which is going to do that um uh + + + align:start position:0% +program which is going to do that um uh +and the touring machine can simil write + + align:start position:0% +and the touring machine can simil write + + + align:start position:0% +and the touring machine can simil write +write code to do that um to get to each + + align:start position:0% +write code to do that um to get to each + + + align:start position:0% +write code to do that um to get to each +possible string one by one and then + + align:start position:0% +possible string one by one and then + + + align:start position:0% +possible string one by one and then +that's what the um enumerator is doing + + align:start position:0% +that's what the um enumerator is doing + + + align:start position:0% +that's what the um enumerator is doing +it's obtaining each of those strings and + + align:start position:0% +it's obtaining each of those strings and + + + align:start position:0% +it's obtaining each of those strings and +then feeding them into M seeing what M + + align:start position:0% +then feeding them into M seeing what M + + + align:start position:0% +then feeding them into M seeing what M +does + + align:start position:0% +does + + + align:start position:0% +does +what I'm trying to get at here is that + + align:start position:0% +what I'm trying to get at here is that + + + align:start position:0% +what I'm trying to get at here is that +it's not good to feed them in run M to + + align:start position:0% +it's not good to feed them in run M to + + + align:start position:0% +it's not good to feed them in run M to +completion on each one before we go into + + align:start position:0% +completion on each one before we go into + + + align:start position:0% +completion on each one before we go into +the next one you really kind of have to + + align:start position:0% +the next one you really kind of have to + + + align:start position:0% +the next one you really kind of have to +do them all in + + align:start position:0% +do them all in + + + align:start position:0% +do them all in +parallel uh um to avoid the problem of + + align:start position:0% +parallel uh um to avoid the problem of + + + align:start position:0% +parallel uh um to avoid the problem of +getting stuck on one string that m is + + align:start position:0% +getting stuck on one string that m is + + + align:start position:0% +getting stuck on one string that m is +looping on um all right so uh this is + + align:start position:0% +looping on um all right so uh this is + + + align:start position:0% +looping on um all right so uh this is +relevant to your homework in fact if I + + align:start position:0% +relevant to your homework in fact if I + + + align:start position:0% +relevant to your homework in fact if I +convert M to an + + align:start position:0% +convert M to an + + + align:start position:0% +convert M to an +enumerator um in this way + + align:start position:0% +enumerator um in this way + + + align:start position:0% +enumerator um in this way +does that enumerator always print the + + align:start position:0% +does that enumerator always print the + + + align:start position:0% +does that enumerator always print the +strings out in string order string order + + align:start position:0% +strings out in string order string order + + + align:start position:0% +strings out in string order string order +is this order here um having them uh the + + align:start position:0% +is this order here um having them uh the + + + align:start position:0% +is this order here um having them uh the +having the shorter strings coming up + + align:start position:0% +having the shorter strings coming up + + + align:start position:0% +having the shorter strings coming up +before the longer strings and within + + align:start position:0% +before the longer strings and within + + + align:start position:0% +before the longer strings and within +strings of a certain length just doing + + align:start position:0% +strings of a certain length just doing + + + align:start position:0% +strings of a certain length just doing +them in lexic graphic + + align:start position:0% +them in lexic graphic + + + align:start position:0% +them in lexic graphic +order um uh so um hopefully you follow + + align:start position:0% +order um uh so um hopefully you follow + + + align:start position:0% +order um uh so um hopefully you follow +that but since you're you know these are + + align:start position:0% +that but since you're you know these are + + + align:start position:0% +that but since you're you know these are +not uh correctness is that doesn't + + align:start position:0% +not uh correctness is that doesn't + + + align:start position:0% +not uh correctness is that doesn't +matter uh for us let me launch that pull + + align:start position:0% +matter uh for us let me launch that pull + + + align:start position:0% +matter uh for us let me launch that pull +let's I'll see how confused how random + + align:start position:0% +let's I'll see how confused how random + + + align:start position:0% +let's I'll see how confused how random +the answer is here + + align:start position:0% + + + + align:start position:0% + +uh so a fair amount of confusion if + + align:start position:0% +uh so a fair amount of confusion if + + + align:start position:0% +uh so a fair amount of confusion if +you're confused obviously you're in good + + align:start position:0% +you're confused obviously you're in good + + + align:start position:0% +you're confused obviously you're in good +company there um okay about to shut this + + align:start position:0% +company there um okay about to shut this + + + align:start position:0% +company there um okay about to shut this +down uh five seconds to + + align:start position:0% +down uh five seconds to + + + align:start position:0% +down uh five seconds to +go okay ending in + + align:start position:0% +go okay ending in + + + align:start position:0% +go okay ending in +now + + align:start position:0% +now + + + align:start position:0% +now +uh all right so the correct answer as + + align:start position:0% +uh all right so the correct answer as + + + align:start position:0% +uh all right so the correct answer as +the majority of you did get is in fact + + align:start position:0% +the majority of you did get is in fact + + + align:start position:0% +the majority of you did get is in fact +that the order is not going to be uh + + align:start position:0% +that the order is not going to be uh + + + align:start position:0% +that the order is not going to be uh +respected here when e uh prints things + + align:start position:0% +respected here when e uh prints things + + + align:start position:0% +respected here when e uh prints things +out it might print out some things later + + align:start position:0% +out it might print out some things later + + + align:start position:0% +out it might print out some things later +in the order before earlier things in + + align:start position:0% +in the order before earlier things in + + + align:start position:0% +in the order before earlier things in +the order what's going to control how um + + align:start position:0% +the order what's going to control how um + + + align:start position:0% +the order what's going to control how um +when m is going to print it out it + + align:start position:0% +when m is going to print it out it + + + align:start position:0% +when m is going to print it out it +really is if M accepts some strings more + + align:start position:0% +really is if M accepts some strings more + + + align:start position:0% +really is if M accepts some strings more +quickly in fewer + + align:start position:0% +quickly in fewer + + + align:start position:0% +quickly in fewer +steps then e might end up printing out + + align:start position:0% +steps then e might end up printing out + + + align:start position:0% +steps then e might end up printing out +though that string earlier in the + + align:start position:0% +though that string earlier in the + + + align:start position:0% +though that string earlier in the +list um than some other string that + + align:start position:0% +list um than some other string that + + + align:start position:0% +list um than some other string that +might be a shorter + + align:start position:0% +might be a shorter + + + align:start position:0% +might be a shorter +string um + + align:start position:0% +string um + + + align:start position:0% +string um +because uh the order in which e is going + + align:start position:0% +because uh the order in which e is going + + + align:start position:0% +because uh the order in which e is going +going to now identify that m is is + + align:start position:0% +going to now identify that m is is + + + align:start position:0% +going to now identify that m is is +accepting those strings is is the um + + align:start position:0% +accepting those strings is is the um + + + align:start position:0% +accepting those strings is is the um +depends upon the speed with which m is + + align:start position:0% +depends upon the speed with which m is + + + align:start position:0% +depends upon the speed with which m is +do actually doing the + + align:start position:0% +do actually doing the + + + align:start position:0% +do actually doing the +accepting so you have to um this is + + align:start position:0% +accepting so you have to um this is + + + align:start position:0% +accepting so you have to um this is +relevant to one of your homeworks + + align:start position:0% +relevant to one of your homeworks + + + align:start position:0% +relevant to one of your homeworks +because if uh what you're going to be at + + align:start position:0% +because if uh what you're going to be at + + + align:start position:0% +because if uh what you're going to be at +to show is that if you start with a + + align:start position:0% +to show is that if you start with a + + + align:start position:0% +to show is that if you start with a +decidable language instead of a + + align:start position:0% +decidable language instead of a + + + align:start position:0% +decidable language instead of a +recognizable language then you can make + + align:start position:0% +recognizable language then you can make + + + align:start position:0% +recognizable language then you can make +an then then you can make an enumerator + + align:start position:0% +an then then you can make an enumerator + + + align:start position:0% +an then then you can make an enumerator +which always prints out things in order + + align:start position:0% +which always prints out things in order + + + align:start position:0% +which always prints out things in order +in the string + + align:start position:0% +in the string + + + align:start position:0% +in the string +order okay and um and vice versa so if + + align:start position:0% +order okay and um and vice versa so if + + + align:start position:0% +order okay and um and vice versa so if +you have and if you have a string which + + align:start position:0% +you have and if you have a string which + + + align:start position:0% +you have and if you have a string which +a numerator which prints things out in + + align:start position:0% +a numerator which prints things out in + + + align:start position:0% +a numerator which prints things out in +string order then the language is + + align:start position:0% +string order then the language is + + + align:start position:0% +string order then the language is +decidable okay so you need to think + + align:start position:0% +decidable okay so you need to think + + + align:start position:0% +decidable okay so you need to think +about + + align:start position:0% +about + + + align:start position:0% +about +that uh One Direction is a fairly simple + + align:start position:0% +that uh One Direction is a fairly simple + + + align:start position:0% +that uh One Direction is a fairly simple +modification of what I just showed um + + align:start position:0% +modification of what I just showed um + + + align:start position:0% +modification of what I just showed um +the other direction is a little bit of + + align:start position:0% +the other direction is a little bit of + + + align:start position:0% +the other direction is a little bit of +more work um so um anyway why don't we + + align:start position:0% +more work um so um anyway why don't we + + + align:start position:0% +more work um so um anyway why don't we +uh uh take our little coffee break here + + align:start position:0% +uh uh take our little coffee break here + + + align:start position:0% +uh uh take our little coffee break here +uh okay so that's an interesting + + align:start position:0% +uh okay so that's an interesting + + + align:start position:0% +uh okay so that's an interesting +question so one question is if there's + + align:start position:0% +question so one question is if there's + + + align:start position:0% +question so one question is if there's +because you know we Sigma has an + + align:start position:0% +because you know we Sigma has an + + + align:start position:0% +because you know we Sigma has an +infinite Sigma star is + + align:start position:0% +infinite Sigma star is + + + align:start position:0% +infinite Sigma star is +infinite um uh if I understand this + + align:start position:0% +infinite um uh if I understand this + + + align:start position:0% +infinite um uh if I understand this +question quite correctly which says you + + align:start position:0% +question quite correctly which says you + + + align:start position:0% +question quite correctly which says you +know it's an infinite number of strings + + align:start position:0% +know it's an infinite number of strings + + + align:start position:0% +know it's an infinite number of strings +here uh how H how does the machine even + + align:start position:0% +here uh how H how does the machine even + + + align:start position:0% +here uh how H how does the machine even +get started because it has to go through + + align:start position:0% +get started because it has to go through + + + align:start position:0% +get started because it has to go through +and enumerate all of it no it's not + + align:start position:0% +and enumerate all of it no it's not + + + align:start position:0% +and enumerate all of it no it's not +first writing down all of those strings + + align:start position:0% +first writing down all of those strings + + + align:start position:0% +first writing down all of those strings +um because yeah you can't write down an + + align:start position:0% +um because yeah you can't write down an + + + align:start position:0% +um because yeah you can't write down an +you can't do this infinite step of + + align:start position:0% +you can't do this infinite step of + + + align:start position:0% +you can't do this infinite step of +writing down all the strings what I had + + align:start position:0% +writing down all the strings what I had + + + align:start position:0% +writing down all the strings what I had +in mind is you're going to take each + + align:start position:0% +in mind is you're going to take each + + + align:start position:0% +in mind is you're going to take each +string in turn first you're going to + + align:start position:0% +string in turn first you're going to + + + align:start position:0% +string in turn first you're going to +take the first string on the list uh of + + align:start position:0% +take the first string on the list uh of + + + align:start position:0% +take the first string on the list uh of +Sigma star run M uh on that string and + + align:start position:0% +Sigma star run M uh on that string and + + + align:start position:0% +Sigma star run M uh on that string and +then the next string in Sigma star run + + align:start position:0% +then the next string in Sigma star run + + + align:start position:0% +then the next string in Sigma star run +it on that string and so on string after + + align:start position:0% +it on that string and so on string after + + + align:start position:0% +it on that string and so on string after +string um and so you're never going to + + align:start position:0% +string um and so you're never going to + + + align:start position:0% +string um and so you're never going to +have infinitely many strings to deal + + align:start position:0% +have infinitely many strings to deal + + + align:start position:0% +have infinitely many strings to deal +with it's just going to be more and more + + align:start position:0% +with it's just going to be more and more + + + align:start position:0% +with it's just going to be more and more +strings as you're going along and uh the + + align:start position:0% +strings as you're going along and uh the + + + align:start position:0% +strings as you're going along and uh the +question I was trying to get at is + + align:start position:0% +question I was trying to get at is + + + align:start position:0% +question I was trying to get at is +whether you're going + + align:start position:0% +whether you're going + + + align:start position:0% +whether you're going +to run each one to compl completion + + align:start position:0% +to run each one to compl completion + + + align:start position:0% +to run each one to compl completion +before you get to the next one or you're + + align:start position:0% +before you get to the next one or you're + + + align:start position:0% +before you get to the next one or you're +going to kind of try to do them all in + + align:start position:0% +going to kind of try to do them all in + + + align:start position:0% +going to kind of try to do them all in +parallel which is what you need to do uh + + align:start position:0% +parallel which is what you need to do uh + + + align:start position:0% +parallel which is what you need to do uh +for to prove this uh this there um won't + + align:start position:0% +for to prove this uh this there um won't + + + align:start position:0% +for to prove this uh this there um won't +there be infinitely many W yes so there + + align:start position:0% +there be infinitely many W yes so there + + + align:start position:0% +there be infinitely many W yes so there +are a similar question infinitely many W + + align:start position:0% +are a similar question infinitely many W + + + align:start position:0% +are a similar question infinitely many W +there are infinitely many W but you know + + align:start position:0% +there are infinitely many W but you know + + + align:start position:0% +there are infinitely many W but you know +it's just an infinite Loop that we're in + + align:start position:0% +it's just an infinite Loop that we're in + + + align:start position:0% +it's just an infinite Loop that we're in +one by one you're taking care of more + + align:start position:0% +one by one you're taking care of more + + + align:start position:0% +one by one you're taking care of more +and more uh wi as you're going um + + align:start position:0% +and more uh wi as you're going um + + + align:start position:0% +and more uh wi as you're going um +uh let's see + + align:start position:0% +uh let's see + + + align:start position:0% +uh let's see +here yes so e is another question is are + + align:start position:0% +here yes so e is another question is are + + + align:start position:0% +here yes so e is another question is are +we running it all all the strings in + + align:start position:0% +we running it all all the strings in + + + align:start position:0% +we running it all all the strings in +parallel yes we are running things all + + align:start position:0% +parallel yes we are running things all + + + align:start position:0% +parallel yes we are running things all +all on running all of the strings in + + align:start position:0% +all on running all of the strings in + + + align:start position:0% +all on running all of the strings in +parallel but you know it's running them + + align:start position:0% +parallel but you know it's running them + + + align:start position:0% +parallel but you know it's running them +in parallel but um these + + align:start position:0% +in parallel but um these + + + align:start position:0% +in parallel but um these +are + + align:start position:0% +are + + + align:start position:0% +are +um uh you know it's we're not defining a + + align:start position:0% +um uh you know it's we're not defining a + + + align:start position:0% +um uh you know it's we're not defining a +parallel touring machine it's running + + align:start position:0% +parallel touring machine it's running + + + align:start position:0% +parallel touring machine it's running +them in parallel using time sharing you + + align:start position:0% +them in parallel using time sharing you + + + align:start position:0% +them in parallel using time sharing you +know it runs a little bit in this block + + align:start position:0% +know it runs a little bit in this block + + + align:start position:0% +know it runs a little bit in this block +runs a little bit in that block and then + + align:start position:0% +runs a little bit in that block and then + + + align:start position:0% +runs a little bit in that block and then +another block and sort of shifts around + + align:start position:0% +another block and sort of shifts around + + + align:start position:0% +another block and sort of shifts around +and sort of does a few steps of each and + + align:start position:0% +and sort of does a few steps of each and + + + align:start position:0% +and sort of does a few steps of each and +that's how it's getting the effect of + + align:start position:0% +that's how it's getting the effect of + + + align:start position:0% +that's how it's getting the effect of +the + + align:start position:0% +the + + + align:start position:0% +the +parallelism + + align:start position:0% + + + + align:start position:0% + +um uh + + align:start position:0% +um uh + + + align:start position:0% +um uh +uh + + align:start position:0% +uh + + + align:start position:0% +uh +okay + + align:start position:0% + + + + align:start position:0% + +um question is would the enumerator + + align:start position:0% +um question is would the enumerator + + + align:start position:0% +um question is would the enumerator +essentially have a print tape and a work + + align:start position:0% +essentially have a print tape and a work + + + align:start position:0% +essentially have a print tape and a work +tape yeah you could think of it as + + align:start position:0% +tape yeah you could think of it as + + + align:start position:0% +tape yeah you could think of it as +having a print tape you know however you + + align:start position:0% +having a print tape you know however you + + + align:start position:0% +having a print tape you know however you +want to formalize it it's it it doesn't + + align:start position:0% +want to formalize it it's it it doesn't + + + align:start position:0% +want to formalize it it's it it doesn't +matter I mean I'm being a little + + align:start position:0% +matter I mean I'm being a little + + + align:start position:0% +matter I mean I'm being a little +Whimsical with attaching it to a picture + + align:start position:0% +Whimsical with attaching it to a picture + + + align:start position:0% +Whimsical with attaching it to a picture +of + + align:start position:0% +of + + + align:start position:0% +of +a a real printer but yeah it just you + + align:start position:0% +a a real printer but yeah it just you + + + align:start position:0% +a a real printer but yeah it just you +think conceptually can a print tape + + align:start position:0% +think conceptually can a print tape + + + align:start position:0% +think conceptually can a print tape +however you like to to think about it + + align:start position:0% +however you like to to think about it + + + align:start position:0% +however you like to to think about it +it's fine um um how can we directly say + + align:start position:0% +it's fine um um how can we directly say + + + align:start position:0% +it's fine um um how can we directly say +that without knowing the program of the + + align:start position:0% +that without knowing the program of the + + + align:start position:0% +that without knowing the program of the +printer + + align:start position:0% +printer + + + align:start position:0% +printer +uh the printer is just there's no we + + align:start position:0% +uh the printer is just there's no we + + + align:start position:0% +uh the printer is just there's no we +don't have to get into the code the + + align:start position:0% +don't have to get into the code the + + + align:start position:0% +don't have to get into the code the +structure of the printer the printer is + + align:start position:0% +structure of the printer the printer is + + + align:start position:0% +structure of the printer the printer is +just uh something where you say print a + + align:start position:0% +just uh something where you say print a + + + align:start position:0% +just uh something where you say print a +string and a and a string comes out + + align:start position:0% +string and a and a string comes out + + + align:start position:0% +string and a and a string comes out +that's all we know about the printer and + + align:start position:0% +that's all we know about the printer and + + + align:start position:0% +that's all we know about the printer and +that's all we need to know um so there's + + align:start position:0% +that's all we need to know um so there's + + + align:start position:0% +that's all we need to know um so there's +no program for the printer uh sorry if I + + align:start position:0% +no program for the printer uh sorry if I + + + align:start position:0% +no program for the printer uh sorry if I +not understanding your question your + + align:start position:0% +not understanding your question your + + + align:start position:0% +not understanding your question your +question but the question literally says + + align:start position:0% +question but the question literally says + + + align:start position:0% +question but the question literally says +how can we say that without knowing the + + align:start position:0% +how can we say that without knowing the + + + align:start position:0% +how can we say that without knowing the +program of the printer + + align:start position:0% +program of the printer + + + align:start position:0% +program of the printer +um so if the machine is decidable why + + align:start position:0% +um so if the machine is decidable why + + + align:start position:0% +um so if the machine is decidable why +does it have to print all strings in + + align:start position:0% +does it have to print all strings in + + + align:start position:0% +does it have to print all strings in +order for example if one string is + + align:start position:0% +order for example if one string is + + + align:start position:0% +order for example if one string is +shorter and it can it be decided + + align:start position:0% +shorter and it can it be decided + + + align:start position:0% +shorter and it can it be decided +later we well yeah if the uh the reason + + align:start position:0% +later we well yeah if the uh the reason + + + align:start position:0% +later we well yeah if the uh the reason +why we want uh so the question is if the + + align:start position:0% +why we want uh so the question is if the + + + align:start position:0% +why we want uh so the question is if the +machine is decidable why why does it + + align:start position:0% +machine is decidable why why does it + + + align:start position:0% +machine is decidable why why does it +have to print all strings in + + align:start position:0% +have to print all strings in + + + align:start position:0% +have to print all strings in +order uh because that's what I'm asking + + align:start position:0% +order uh because that's what I'm asking + + + align:start position:0% +order uh because that's what I'm asking +you to do in the problem that's what the + + align:start position:0% +you to do in the problem that's what the + + + align:start position:0% +you to do in the problem that's what the +if you read the problem I think it's + + align:start position:0% +if you read the problem I think it's + + + align:start position:0% +if you read the problem I think it's +number five on the pet that's what I'm + + align:start position:0% +number five on the pet that's what I'm + + + align:start position:0% +number five on the pet that's what I'm +asking you to do that's why you have to + + align:start position:0% +asking you to do that's why you have to + + + align:start position:0% +asking you to do that's why you have to +print it in order uh otherwise you + + align:start position:0% +print it in order uh otherwise you + + + align:start position:0% +print it in order uh otherwise you +wouldn't have to worry about printing in + + align:start position:0% +wouldn't have to worry about printing in + + + align:start position:0% +wouldn't have to worry about printing in +order it's just because I'm asking you + + align:start position:0% +order it's just because I'm asking you + + + align:start position:0% +order it's just because I'm asking you +to um okay so I think we're at a time + + align:start position:0% +to um okay so I think we're at a time + + + align:start position:0% +to um okay so I think we're at a time +let's um let us move back into um our + + align:start position:0% +let's um let us move back into um our + + + align:start position:0% +let's um let us move back into um our +our material um um okay second half + + align:start position:0% +our material um um okay second half + + + align:start position:0% +our material um um okay second half +Church Turing + + align:start position:0% +Church Turing + + + align:start position:0% +Church Turing +thesis um so Church uh this is going + + align:start position:0% +thesis um so Church uh this is going + + + align:start position:0% +thesis um so Church uh this is going +back into the bit of the history of the + + align:start position:0% +back into the bit of the history of the + + + align:start position:0% +back into the bit of the history of the +subject back to the 1930s + + align:start position:0% +subject back to the 1930s + + + align:start position:0% +subject back to the 1930s +um back then people were uh interested + + align:start position:0% +um back then people were uh interested + + + align:start position:0% +um back then people were uh interested +in formulating the notion of what do we + + align:start position:0% +in formulating the notion of what do we + + + align:start position:0% +in formulating the notion of what do we +mean by algorithm they didn't even call + + align:start position:0% +mean by algorithm they didn't even call + + + align:start position:0% +mean by algorithm they didn't even call +it algorithm um and those they call it + + align:start position:0% +it algorithm um and those they call it + + + align:start position:0% +it algorithm um and those they call it +some people call it procedure some + + align:start position:0% +some people call it procedure some + + + align:start position:0% +some people call it procedure some +people call it effective procedure um + + align:start position:0% +people call it effective procedure um + + + align:start position:0% +people call it effective procedure um +some people call it um uh effective + + align:start position:0% +some people call it um uh effective + + + align:start position:0% +some people call it um uh effective +calculation um but you know people had + + align:start position:0% +calculation um but you know people had + + + align:start position:0% +calculation um but you know people had +in their minds mathematicians have been + + align:start position:0% +in their minds mathematicians have been + + + align:start position:0% +in their minds mathematicians have been +dealing for centuries thousands of years + + align:start position:0% +dealing for centuries thousands of years + + + align:start position:0% +dealing for centuries thousands of years +with procedures for doing things that's + + align:start position:0% +with procedures for doing things that's + + + align:start position:0% +with procedures for doing things that's +a very natural thing and mathematical + + align:start position:0% +a very natural thing and mathematical + + + align:start position:0% +a very natural thing and mathematical +logicians in particular church and + + align:start position:0% +logicians in particular church and + + + align:start position:0% +logicians in particular church and +Turing uh Turing is somebody you surely + + align:start position:0% +Turing uh Turing is somebody you surely + + + align:start position:0% +Turing uh Turing is somebody you surely +obviously have heard of church maybe not + + align:start position:0% +obviously have heard of church maybe not + + + align:start position:0% +obviously have heard of church maybe not +um uh church was touring's thesis + + align:start position:0% +um uh church was touring's thesis + + + align:start position:0% +um uh church was touring's thesis +advisor in fact um and they both were + + align:start position:0% +advisor in fact um and they both were + + + align:start position:0% +advisor in fact um and they both were +coming out of the uh mathematical logic + + align:start position:0% +coming out of the uh mathematical logic + + + align:start position:0% +coming out of the uh mathematical logic +field of mathematics and uh using trying + + align:start position:0% +field of mathematics and uh using trying + + + align:start position:0% +field of mathematics and uh using trying +to use mathematical logic to formalize + + align:start position:0% +to use mathematical logic to formalize + + + align:start position:0% +to use mathematical logic to formalize +this intuitive notion of what we have + + align:start position:0% +this intuitive notion of what we have + + + align:start position:0% +this intuitive notion of what we have +had for for centuries about what a what + + align:start position:0% +had for for centuries about what a what + + + align:start position:0% +had for for centuries about what a what +a procedure is what is it what what is + + align:start position:0% +a procedure is what is it what what is + + + align:start position:0% +a procedure is what is it what what is +what is an algorithm + + align:start position:0% +what is an algorithm + + + align:start position:0% +what is an algorithm +U and um back in those days you know + + align:start position:0% +U and um back in those days you know + + + align:start position:0% +U and um back in those days you know +they came up with different ways of of + + align:start position:0% +they came up with different ways of of + + + align:start position:0% +they came up with different ways of of +formalizing it um uh so you know here we + + align:start position:0% +formalizing it um uh so you know here we + + + align:start position:0% +formalizing it um uh so you know here we +had this notion of algorithm which is + + align:start position:0% +had this notion of algorithm which is + + + align:start position:0% +had this notion of algorithm which is +kind of intuitive concept + + align:start position:0% +kind of intuitive concept + + + align:start position:0% +kind of intuitive concept +touring proposed touring machine as a + + align:start position:0% +touring proposed touring machine as a + + + align:start position:0% +touring proposed touring machine as a +way of capturing that in a formal way + + align:start position:0% +way of capturing that in a formal way + + + align:start position:0% +way of capturing that in a formal way +for mathematically precise way other + + align:start position:0% +for mathematically precise way other + + + align:start position:0% +for mathematically precise way other +people came up with other ways of doing + + align:start position:0% +people came up with other ways of doing + + + align:start position:0% +people came up with other ways of doing +it + + align:start position:0% +it + + + align:start position:0% +it +um and back then it wasn't obvious that + + align:start position:0% +um and back then it wasn't obvious that + + + align:start position:0% +um and back then it wasn't obvious that +all of those different formulations + + align:start position:0% +all of those different formulations + + + align:start position:0% +all of those different formulations +would end up giving you equivalent + + align:start position:0% +would end up giving you equivalent + + + align:start position:0% +would end up giving you equivalent +Concepts equivalent Notions um and in + + align:start position:0% +Concepts equivalent Notions um and in + + + align:start position:0% +Concepts equivalent Notions um and in +fact they proved in Fairly elaborate + + align:start position:0% +fact they proved in Fairly elaborate + + + align:start position:0% +fact they proved in Fairly elaborate +detail that the different methods that + + align:start position:0% +detail that the different methods that + + + align:start position:0% +detail that the different methods that +people came up with it was the Lambda + + align:start position:0% +people came up with it was the Lambda + + + align:start position:0% +people came up with it was the Lambda +calculus there was rewriting systems + + align:start position:0% +calculus there was rewriting systems + + + align:start position:0% +calculus there was rewriting systems +there were several methods that were + + align:start position:0% +there were several methods that were + + + align:start position:0% +there were several methods that were +proposed for formalizing this notion and + + align:start position:0% +proposed for formalizing this notion and + + + align:start position:0% +proposed for formalizing this notion and +they all turned out to be equivalent to + + align:start position:0% +they all turned out to be equivalent to + + + align:start position:0% +they all turned out to be equivalent to +one another um in today that seems kind + + align:start position:0% +one another um in today that seems kind + + + align:start position:0% +one another um in today that seems kind +of obvious even though I went through + + align:start position:0% +of obvious even though I went through + + + align:start position:0% +of obvious even though I went through +some effort to prove that uh just to + + align:start position:0% +some effort to prove that uh just to + + + align:start position:0% +some effort to prove that uh just to +give you a feeling for how those things + + align:start position:0% +give you a feeling for how those things + + + align:start position:0% +give you a feeling for how those things +uh go you know that you know if you have + + align:start position:0% +uh go you know that you know if you have + + + align:start position:0% +uh go you know that you know if you have +programs if you have Pascal and Java say + + align:start position:0% +programs if you have Pascal and Java say + + + align:start position:0% +programs if you have Pascal and Java say +and thinking about what you can do + + align:start position:0% +and thinking about what you can do + + + align:start position:0% +and thinking about what you can do +mathematically in in those I'm not + + align:start position:0% +mathematically in in those I'm not + + + align:start position:0% +mathematically in in those I'm not +talking about their ability to inter + + align:start position:0% +talking about their ability to inter + + + align:start position:0% +talking about their ability to inter +face with you know windows and so on but + + align:start position:0% +face with you know windows and so on but + + + align:start position:0% +face with you know windows and so on but +just the mathematical + + align:start position:0% +just the mathematical + + + align:start position:0% +just the mathematical +capabilities the capability of doing + + align:start position:0% +capabilities the capability of doing + + + align:start position:0% +capabilities the capability of doing +mathematical calculations or functions + + align:start position:0% +mathematical calculations or functions + + + align:start position:0% +mathematical calculations or functions +with a a pascal program or a Java + + align:start position:0% +with a a pascal program or a Java + + + align:start position:0% +with a a pascal program or a Java +program you know it would be absurd to + + align:start position:0% +program you know it would be absurd to + + + align:start position:0% +program you know it would be absurd to +think there's some program that you can + + align:start position:0% +think there's some program that you can + + + align:start position:0% +think there's some program that you can +write in Java that you can't write in + + align:start position:0% +write in Java that you can't write in + + + align:start position:0% +write in Java that you can't write in +Pascal um or python + + align:start position:0% +Pascal um or python + + + align:start position:0% +Pascal um or python +uh uh and the reason is we know you can + + align:start position:0% +uh uh and the reason is we know you can + + + align:start position:0% +uh uh and the reason is we know you can +compile python into Java and you can + + align:start position:0% +compile python into Java and you can + + + align:start position:0% +compile python into Java and you can +compile Java back into python that tells + + align:start position:0% +compile Java back into python that tells + + + align:start position:0% +compile Java back into python that tells +you that the two systems of two + + align:start position:0% +you that the two systems of two + + + align:start position:0% +you that the two systems of two +programming languages are equivalent in + + align:start position:0% +programming languages are equivalent in + + + align:start position:0% +programming languages are equivalent in +power um that wasn't obvious that from + + align:start position:0% +power um that wasn't obvious that from + + + align:start position:0% +power um that wasn't obvious that from +the get-go to these folks so they um + + align:start position:0% +the get-go to these folks so they um + + + align:start position:0% +the get-go to these folks so they um +observed that uh all of the different + + align:start position:0% +observed that uh all of the different + + + align:start position:0% +observed that uh all of the different +efforts they came at formalizing + + align:start position:0% +efforts they came at formalizing + + + align:start position:0% +efforts they came at formalizing +algorithm all were equivalent to one + + align:start position:0% +algorithm all were equivalent to one + + + align:start position:0% +algorithm all were equivalent to one +another that was that that was a kind of + + align:start position:0% +another that was that that was a kind of + + + align:start position:0% +another that was that that was a kind of +a breakthrough moment when they realized + + align:start position:0% +a breakthrough moment when they realized + + + align:start position:0% +a breakthrough moment when they realized +that they're all that not all the ways + + align:start position:0% +that they're all that not all the ways + + + align:start position:0% +that they're all that not all the ways +that they've come up with and once they + + align:start position:0% +that they've come up with and once they + + + align:start position:0% +that they've come up with and once they +got the idea they realize all reasonable + + align:start position:0% +got the idea they realize all reasonable + + + align:start position:0% +got the idea they realize all reasonable +ways of doing it are always going to be + + align:start position:0% +ways of doing it are always going to be + + + align:start position:0% +ways of doing it are always going to be +equivalent um and so that suggested that + + align:start position:0% +equivalent um and so that suggested that + + + align:start position:0% +equivalent um and so that suggested that +they've really captured this notion of + + align:start position:0% +they've really captured this notion of + + + align:start position:0% +they've really captured this notion of +algorithm by any one of those methods + + align:start position:0% +algorithm by any one of those methods + + + align:start position:0% +algorithm by any one of those methods +say a touring machine and that's what + + align:start position:0% +say a touring machine and that's what + + + align:start position:0% +say a touring machine and that's what +they took you can't prove that because + + align:start position:0% +they took you can't prove that because + + + align:start position:0% +they took you can't prove that because +algorithms are an intuitive notion but + + align:start position:0% +algorithms are an intuitive notion but + + + align:start position:0% +algorithms are an intuitive notion but +the fact that we're able to capture that + + align:start position:0% +the fact that we're able to capture that + + + align:start position:0% +the fact that we're able to capture that +in a formal way that's what we call + + align:start position:0% +in a formal way that's what we call + + + align:start position:0% +in a formal way that's what we call +today the church touring + + align:start position:0% +today the church touring + + + align:start position:0% +today the church touring +thesis okay um so um that is uh um so + + align:start position:0% +thesis okay um so um that is uh um so + + + align:start position:0% +thesis okay um so um that is uh um so +any of these methods um uh capture the + + align:start position:0% +any of these methods um uh capture the + + + align:start position:0% +any of these methods um uh capture the +notion of algorithm as we + + align:start position:0% +notion of algorithm as we + + + align:start position:0% +notion of algorithm as we +described and that has had a big impact + + align:start position:0% +described and that has had a big impact + + + align:start position:0% +described and that has had a big impact +on mathematics uh so now I just want + + align:start position:0% +on mathematics uh so now I just want + + + align:start position:0% +on mathematics uh so now I just want +to just give me one second + + align:start position:0% +to just give me one second + + + align:start position:0% +to just give me one second +here all right here's a checkin on this + + align:start position:0% +here all right here's a checkin on this + + + align:start position:0% +here all right here's a checkin on this +one um so you know Alan Turing so here + + align:start position:0% +one um so you know Alan Turing so here + + + align:start position:0% +one um so you know Alan Turing so here +are some facts which may or may not be + + align:start position:0% +are some facts which may or may not be + + + align:start position:0% +are some facts which may or may not be +true about Allen tur um so uh now you + + align:start position:0% +true about Allen tur um so uh now you + + + align:start position:0% +true about Allen tur um so uh now you +get to pick all of the ones that apply + + align:start position:0% +get to pick all of the ones that apply + + + align:start position:0% +get to pick all of the ones that apply +um based on your knowledge obviously + + align:start position:0% +um based on your knowledge obviously + + + align:start position:0% +um based on your knowledge obviously +this is + + align:start position:0% +this is + + + align:start position:0% +this is +not uh something this is more for fun + + align:start position:0% +not uh something this is more for fun + + + align:start position:0% +not uh something this is more for fun +but um or historical interest um but + + align:start position:0% +but um or historical interest um but + + + align:start position:0% +but um or historical interest um but +here is uh let's launch that poll see + + align:start position:0% +here is uh let's launch that poll see + + + align:start position:0% +here is uh let's launch that poll see +what how much you know about uh Mr + + align:start position:0% +what how much you know about uh Mr + + + align:start position:0% +what how much you know about uh Mr +Turing + + align:start position:0% + + + + align:start position:0% + +um check all that + + align:start position:0% + + + + align:start position:0% + +apply okay almost done please + + align:start position:0% +apply okay almost done please + + + align:start position:0% +apply okay almost done please +please let's wrap it up I think that's + + align:start position:0% +please let's wrap it up I think that's + + + align:start position:0% +please let's wrap it up I think that's +everybody okay two seconds please get + + align:start position:0% +everybody okay two seconds please get + + + align:start position:0% +everybody okay two seconds please get +credit for doing this and polling in + + align:start position:0% +credit for doing this and polling in + + + align:start position:0% +credit for doing this and polling in +fact it's kind of interesting here + + align:start position:0% +fact it's kind of interesting here + + + align:start position:0% +fact it's kind of interesting here +uh + + align:start position:0% +uh + + + align:start position:0% +uh +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +um + + align:start position:0% +um + + + align:start position:0% +um +uh you all do know that he was a code + + align:start position:0% +uh you all do know that he was a code + + + align:start position:0% +uh you all do know that he was a code +breaker uh he was a um worked uh in fact + + align:start position:0% +breaker uh he was a um worked uh in fact + + + align:start position:0% +breaker uh he was a um worked uh in fact +did was part of a team I think led the + + align:start position:0% +did was part of a team I think led the + + + align:start position:0% +did was part of a team I think led the +team which broke the the German code um + + align:start position:0% +team which broke the the German code um + + + align:start position:0% +team which broke the the German code um +during World War II you know the Turing + + align:start position:0% +during World War II you know the Turing + + + align:start position:0% +during World War II you know the Turing +test is a famous uh thing for how do you + + align:start position:0% +test is a famous uh thing for how do you + + + align:start position:0% +test is a famous uh thing for how do you +characterize when you have an + + align:start position:0% +characterize when you have an + + + align:start position:0% +characterize when you have an +intelligent machine um so he definitely + + align:start position:0% +intelligent machine um so he definitely + + + align:start position:0% +intelligent machine um so he definitely +worked in AI he worked in biology as + + align:start position:0% +worked in AI he worked in biology as + + + align:start position:0% +worked in AI he worked in biology as +well um he has a paper that less well + + align:start position:0% +well um he has a paper that less well + + + align:start position:0% +well um he has a paper that less well +known to computer scientists but if you + + align:start position:0% +known to computer scientists but if you + + + align:start position:0% +known to computer scientists but if you +look him up um on Wikipedia where I get + + align:start position:0% +look him up um on Wikipedia where I get + + + align:start position:0% +look him up um on Wikipedia where I get +all my information + + align:start position:0% +all my information + + + align:start position:0% +all my information +uh he actually and I knew this anyway uh + + align:start position:0% +uh he actually and I knew this anyway uh + + + align:start position:0% +uh he actually and I knew this anyway uh +he has a very famous paper an + + align:start position:0% +he has a very famous paper an + + + align:start position:0% +he has a very famous paper an +influential paper on how + + align:start position:0% +influential paper on how + + + align:start position:0% +influential paper on how +um for example spots arise on um on + + align:start position:0% +um for example spots arise on um on + + + align:start position:0% +um for example spots arise on um on +tiger on on leopards and stripes on + + align:start position:0% +tiger on on leopards and stripes on + + + align:start position:0% +tiger on on leopards and stripes on +tigers and so on um gave a kind of + + align:start position:0% +tigers and so on um gave a kind of + + + align:start position:0% +tigers and so on um gave a kind of +mathematical model for that which + + align:start position:0% +mathematical model for that which + + + align:start position:0% +mathematical model for that which +actually proves actually is uh quite + + align:start position:0% +actually proves actually is uh quite + + + align:start position:0% +actually proves actually is uh quite +does capture things in an accurate way + + align:start position:0% +does capture things in an accurate way + + + align:start position:0% +does capture things in an accurate way +uh as as was shown subsequent to that uh + + align:start position:0% +uh as as was shown subsequent to that uh + + + align:start position:0% +uh as as was shown subsequent to that uh +was imprisoned for being gay in fact as + + align:start position:0% +was imprisoned for being gay in fact as + + + align:start position:0% +was imprisoned for being gay in fact as +far as I know from his history he was + + align:start position:0% +far as I know from his history he was + + + align:start position:0% +far as I know from his history he was +not imprisoned for being gay um he was + + align:start position:0% +not imprisoned for being gay um he was + + + align:start position:0% +not imprisoned for being gay um he was +convicted of being gay um and was given + + align:start position:0% +convicted of being gay um and was given + + + align:start position:0% +convicted of being gay um and was given +a choice to go to prison or to take + + align:start position:0% +a choice to go to prison or to take + + + align:start position:0% +a choice to go to prison or to take +chemicals to + + align:start position:0% +chemicals to + + + align:start position:0% +chemicals to +cure him from being gay and he opted not + + align:start position:0% +cure him from being gay and he opted not + + + align:start position:0% +cure him from being gay and he opted not +to go to prison and take the + + align:start position:0% +to go to prison and take the + + + align:start position:0% +to go to prison and take the +chemicals uh and sadly he committed + + align:start position:0% +chemicals uh and sadly he committed + + + align:start position:0% +chemicals uh and sadly he committed +suicide um two years after that so um he + + align:start position:0% +suicide um two years after that so um he + + + align:start position:0% +suicide um two years after that so um he +was + + align:start position:0% +was + + + align:start position:0% +was +um treated very treated very badly by uh + + align:start position:0% +um treated very treated very badly by uh + + + align:start position:0% +um treated very treated very badly by uh +the British society and British + + align:start position:0% +the British society and British + + + align:start position:0% +the British society and British +government uh despite having the great + + align:start position:0% +government uh despite having the great + + + align:start position:0% +government uh despite having the great +work that he had done um + + align:start position:0% +work that he had done um + + + align:start position:0% +work that he had done um +and um you might think that he has been + + align:start position:0% +and um you might think that he has been + + + align:start position:0% +and um you might think that he has been +honored by appearing on a British bank + + align:start position:0% +honored by appearing on a British bank + + + align:start position:0% +honored by appearing on a British bank +note that's also not true um uh but the + + align:start position:0% +note that's also not true um uh but the + + + align:start position:0% +note that's also not true um uh but the +good news is he's not uh currently on a + + align:start position:0% +good news is he's not uh currently on a + + + align:start position:0% +good news is he's not uh currently on a +British bank note but he's going to be + + align:start position:0% +British bank note but he's going to be + + + align:start position:0% +British bank note but he's going to be +on a British bank note starting next + + align:start position:0% +on a British bank note starting next + + + align:start position:0% +on a British bank note starting next +year um so that is uh um so that's uh + + align:start position:0% +year um so that is uh um so that's uh + + + align:start position:0% +year um so that is uh um so that's uh +you know along with um Winston Churchill + + align:start position:0% +you know along with um Winston Churchill + + + align:start position:0% +you know along with um Winston Churchill +and a number of other notable Brits he's + + align:start position:0% +and a number of other notable Brits he's + + + align:start position:0% +and a number of other notable Brits he's +going to be on the the 50 pound b Bank + + align:start position:0% + + + + align:start position:0% + +okay um so let us continue + + align:start position:0% +okay um so let us continue + + + align:start position:0% +okay um so let us continue +um so as I mentioned uh the church + + align:start position:0% +um so as I mentioned uh the church + + + align:start position:0% +um so as I mentioned uh the church +string thesis is important for + + align:start position:0% +string thesis is important for + + + align:start position:0% +string thesis is important for +mathematics um and it has to do with + + align:start position:0% +mathematics um and it has to do with + + + align:start position:0% +mathematics um and it has to do with +these Hilbert problems I don't know how + + align:start position:0% +these Hilbert problems I don't know how + + + align:start position:0% +these Hilbert problems I don't know how +many of you have encountered that David + + align:start position:0% +many of you have encountered that David + + + align:start position:0% +many of you have encountered that David +Hilbert was widely considered to be the + + align:start position:0% +Hilbert was widely considered to be the + + + align:start position:0% +Hilbert was widely considered to be the +perhaps the greatest mathematician of + + align:start position:0% +perhaps the greatest mathematician of + + + align:start position:0% +perhaps the greatest mathematician of +his day um and um you know every four + + align:start position:0% +his day um and um you know every four + + + align:start position:0% +his day um and um you know every four +years mathematicians get together for an + + align:start position:0% +years mathematicians get together for an + + + align:start position:0% +years mathematicians get together for an +international Congress called the + + align:start position:0% +international Congress called the + + + align:start position:0% +international Congress called the +international Congress of mathematicians + + align:start position:0% +international Congress of mathematicians + + + align:start position:0% +international Congress of mathematicians +it was you know even that's been going + + align:start position:0% +it was you know even that's been going + + + align:start position:0% +it was you know even that's been going +on for over a hundred years and he was + + align:start position:0% +on for over a hundred years and he was + + + align:start position:0% +on for over a hundred years and he was +invited to the + + align:start position:0% +invited to the + + + align:start position:0% +invited to the +1900 uh meeting to give a talk about + + align:start position:0% +1900 uh meeting to give a talk about + + + align:start position:0% +1900 uh meeting to give a talk about +anything he wanted and what he decided + + align:start position:0% +anything he wanted and what he decided + + + align:start position:0% +anything he wanted and what he decided +to do in during that presentation is + + align:start position:0% +to do in during that presentation is + + + align:start position:0% +to do in during that presentation is +give it is present + + align:start position:0% +give it is present + + + align:start position:0% +give it is present +23 uh + + align:start position:0% +23 uh + + + align:start position:0% +23 uh +problems that would be a challenge for + + align:start position:0% +problems that would be a challenge for + + + align:start position:0% +problems that would be a challenge for +mathematicians for the coming + + align:start position:0% + + + + align:start position:0% + +Century um and um uh you know we're + + align:start position:0% +Century um and um uh you know we're + + + align:start position:0% +Century um and um uh you know we're +running a little short on time so I'm + + align:start position:0% +running a little short on time so I'm + + + align:start position:0% +running a little short on time so I'm +not going to go into them some of these + + align:start position:0% +not going to go into them some of these + + + align:start position:0% +not going to go into them some of these +we'll talk about later uh but the 10th + + align:start position:0% +we'll talk about later uh but the 10th + + + align:start position:0% +we'll talk about later uh but the 10th +problem here is about algorithms the + + align:start position:0% +problem here is about algorithms the + + + align:start position:0% +problem here is about algorithms the +10th problem on Hilbert's list of called + + align:start position:0% +10th problem on Hilbert's list of called + + + align:start position:0% +10th problem on Hilbert's list of called +called Hilbert's 10th problem is a + + align:start position:0% +called Hilbert's 10th problem is a + + + align:start position:0% +called Hilbert's 10th problem is a +problem about algorithms and it says + + align:start position:0% +problem about algorithms and it says + + + align:start position:0% +problem about algorithms and it says +give an algorithm for solving what are + + align:start position:0% +give an algorithm for solving what are + + + align:start position:0% +give an algorithm for solving what are +called di Fantine + + align:start position:0% +called di Fantine + + + align:start position:0% +called di Fantine +equations um he didn't call it an + + align:start position:0% +equations um he didn't call it an + + + align:start position:0% +equations um he didn't call it an +algorithm he call it some uh you know + + align:start position:0% +algorithm he call it some uh you know + + + align:start position:0% +algorithm he call it some uh you know +finite procedure or something like that + + align:start position:0% +finite procedure or something like that + + + align:start position:0% +finite procedure or something like that +but you know you what are diophantine + + align:start position:0% +but you know you what are diophantine + + + align:start position:0% +but you know you what are diophantine +equations I'm glad you asked + + align:start position:0% +equations I'm glad you asked + + + align:start position:0% +equations I'm glad you asked +uh Dian equations uh what are they well + + align:start position:0% +uh Dian equations uh what are they well + + + align:start position:0% +uh Dian equations uh what are they well +they're very simple they're just + + align:start position:0% +they're very simple they're just + + + align:start position:0% +they're very simple they're just +polinomial equations like you know does + + align:start position:0% +polinomial equations like you know does + + + align:start position:0% +polinomial equations like you know does +this polinomial equal some constant for + + align:start position:0% +this polinomial equal some constant for + + + align:start position:0% +this polinomial equal some constant for +example um but where you're looking for + + align:start position:0% +example um but where you're looking for + + + align:start position:0% +example um but where you're looking for +the solutions you know the polinomial + + align:start position:0% +the solutions you know the polinomial + + + align:start position:0% +the solutions you know the polinomial +are variables you're looking for the + + align:start position:0% +are variables you're looking for the + + + align:start position:0% +are variables you're looking for the +solutions but you're only allowing the + + align:start position:0% +solutions but you're only allowing the + + + align:start position:0% +solutions but you're only allowing the +solutions to be + + align:start position:0% +solutions to be + + + align:start position:0% +solutions to be +integers so here's an example um so I + + align:start position:0% +integers so here's an example um so I + + + align:start position:0% +integers so here's an example um so I +give you this polinomial um here I'm + + align:start position:0% +give you this polinomial um here I'm + + + align:start position:0% +give you this polinomial um here I'm +setting it equal to seven and I want to + + align:start position:0% +setting it equal to seven and I want to + + + align:start position:0% +setting it equal to seven and I want to +solve that equation + + align:start position:0% +solve that equation + + + align:start position:0% +solve that equation +so it has these three variables X Y and + + align:start position:0% +so it has these three variables X Y and + + + align:start position:0% +so it has these three variables X Y and +Z so you have to find a solution there + + align:start position:0% +Z so you have to find a solution there + + + align:start position:0% +Z so you have to find a solution there +but I'm only going to allow you to have + + align:start position:0% +but I'm only going to allow you to have + + + align:start position:0% +but I'm only going to allow you to have +plugin Z integers and in fact there is a + + align:start position:0% +plugin Z integers and in fact there is a + + + align:start position:0% +plugin Z integers and in fact there is a +solution in integers one two and minus + + align:start position:0% +solution in integers one two and minus + + + align:start position:0% +solution in integers one two and minus +two if you plug it in you'll see it + + align:start position:0% +two if you plug it in you'll see it + + + align:start position:0% +two if you plug it in you'll see it +works all right um now the general + + align:start position:0% +works all right um now the general + + + align:start position:0% +works all right um now the general +problem that Hilbert was addressing is + + align:start position:0% +problem that Hilbert was addressing is + + + align:start position:0% +problem that Hilbert was addressing is +suppose I give you a + + align:start position:0% +suppose I give you a + + + align:start position:0% +suppose I give you a +polinomial um let's say it set it it set + + align:start position:0% +polinomial um let's say it set it it set + + + align:start position:0% +polinomial um let's say it set it it set +to zero so we're looking for roots of + + align:start position:0% +to zero so we're looking for roots of + + + align:start position:0% +to zero so we're looking for roots of +the polinomial but just some polinomial + + align:start position:0% +the polinomial but just some polinomial + + + align:start position:0% +the polinomial but just some polinomial +equation you can always put it in this + + align:start position:0% +equation you can always put it in this + + + align:start position:0% +equation you can always put it in this +form and I want to know uh does it have + + align:start position:0% +form and I want to know uh does it have + + + align:start position:0% +form and I want to know uh does it have +a solution in + + align:start position:0% +a solution in + + + align:start position:0% +a solution in +integers um and what I want what I'm + + align:start position:0% +integers um and what I want what I'm + + + align:start position:0% +integers um and what I want what I'm +looking for is a procedure which will + + align:start position:0% +looking for is a procedure which will + + + align:start position:0% +looking for is a procedure which will +tell me yes or no I want to know um give + + align:start position:0% +tell me yes or no I want to know um give + + + align:start position:0% +tell me yes or no I want to know um give +an algorithm to answer that question for + + align:start position:0% +an algorithm to answer that question for + + + align:start position:0% +an algorithm to answer that question for +a given polinomial or the or using the + + align:start position:0% +a given polinomial or the or using the + + + align:start position:0% +a given polinomial or the or using the +language of this course defining this in + + align:start position:0% +language of this course defining this in + + + align:start position:0% +language of this course defining this in +terms of a + + align:start position:0% +terms of a + + + align:start position:0% +terms of a +language uh decide this language give a + + align:start position:0% +language uh decide this language give a + + + align:start position:0% +language uh decide this language give a +give a turing machine which will decide + + align:start position:0% +give a turing machine which will decide + + + align:start position:0% +give a turing machine which will decide +yes or no for any given polinomial yes + + align:start position:0% +yes or no for any given polinomial yes + + + align:start position:0% +yes or no for any given polinomial yes +there is a solution in integers no there + + align:start position:0% +there is a solution in integers no there + + + align:start position:0% +there is a solution in integers no there +is no solution in + + align:start position:0% +is no solution in + + + align:start position:0% +is no solution in +okay and um uh that is a um uh um uh + + align:start position:0% +okay and um uh that is a um uh um uh + + + align:start position:0% +okay and um uh that is a um uh um uh +that that was what um Hilbert asked in + + align:start position:0% +that that was what um Hilbert asked in + + + align:start position:0% +that that was what um Hilbert asked in +his 10th problem given algorithm now as + + align:start position:0% +his 10th problem given algorithm now as + + + align:start position:0% +his 10th problem given algorithm now as +we know now took um 70 years to get the + + align:start position:0% +we know now took um 70 years to get the + + + align:start position:0% +we know now took um 70 years to get the +answer that um uh that there is no such + + align:start position:0% +answer that um uh that there is no such + + + align:start position:0% +answer that um uh that there is no such +algorithm it's an undecidable problem + + align:start position:0% +algorithm it's an undecidable problem + + + align:start position:0% +algorithm it's an undecidable problem +and we'll talk about that a little bit + + align:start position:0% +and we'll talk about that a little bit + + + align:start position:0% +and we'll talk about that a little bit +later in the term but um there is D is + + align:start position:0% +later in the term but um there is D is + + + align:start position:0% +later in the term but um there is D is +not a decidable + + align:start position:0% +not a decidable + + + align:start position:0% +not a decidable +language now um there was no hope of + + align:start position:0% +language now um there was no hope of + + + align:start position:0% +language now um there was no hope of +coming up with that answer in 1900 or + + align:start position:0% +coming up with that answer in 1900 or + + + align:start position:0% +coming up with that answer in 1900 or +even in + + align:start position:0% +even in + + + align:start position:0% +even in +1910 because we didn't have a formal + + align:start position:0% +1910 because we didn't have a formal + + + align:start position:0% +1910 because we didn't have a formal +idea of what an algorithm is that had to + + align:start position:0% +idea of what an algorithm is that had to + + + align:start position:0% +idea of what an algorithm is that had to +wait until the church Turing thesis told + + align:start position:0% +wait until the church Turing thesis told + + + align:start position:0% +wait until the church Turing thesis told +us that algorithms really are touring + + align:start position:0% +us that algorithms really are touring + + + align:start position:0% +us that algorithms really are touring +machines that there is a formal way of + + align:start position:0% +machines that there is a formal way of + + + align:start position:0% +machines that there is a formal way of +saying what an algorithm is + + align:start position:0% +saying what an algorithm is + + + align:start position:0% +saying what an algorithm is +and once you had that notion then you + + align:start position:0% +and once you had that notion then you + + + align:start position:0% +and once you had that notion then you +could prove that there is no touring + + align:start position:0% +could prove that there is no touring + + + align:start position:0% +could prove that there is no touring +machine but before that you had only + + align:start position:0% +machine but before that you had only + + + align:start position:0% +machine but before that you had only +this vague notion intuitive notion of + + align:start position:0% +this vague notion intuitive notion of + + + align:start position:0% +this vague notion intuitive notion of +what an algorithm is and so there was no + + align:start position:0% +what an algorithm is and so there was no + + + align:start position:0% +what an algorithm is and so there was no +hope of ever answering that because the + + align:start position:0% +hope of ever answering that because the + + + align:start position:0% +hope of ever answering that because the +in fact the answer is there is no such + + align:start position:0% +in fact the answer is there is no such + + + align:start position:0% +in fact the answer is there is no such +algorithm okay now um I'll give this as + + align:start position:0% +algorithm okay now um I'll give this as + + + align:start position:0% +algorithm okay now um I'll give this as +a little exercise to you we're a little + + align:start position:0% +a little exercise to you we're a little + + + align:start position:0% +a little exercise to you we're a little +bit running short on time but this + + align:start position:0% +bit running short on time but this + + + align:start position:0% +bit running short on time but this +language D is in fact a recognizable + + align:start position:0% +language D is in fact a recognizable + + + align:start position:0% +language D is in fact a recognizable +language so I would suggest you think + + align:start position:0% +language so I would suggest you think + + + align:start position:0% +language so I would suggest you think +about that offline um but basically you + + align:start position:0% +about that offline um but basically you + + + align:start position:0% +about that offline um but basically you +know you can try plugging in different + + align:start position:0% +know you can try plugging in different + + + align:start position:0% +know you can try plugging in different +values for these variables and if you + + align:start position:0% +values for these variables and if you + + + align:start position:0% +values for these variables and if you +ever find a you know the um that it + + align:start position:0% +ever find a you know the um that it + + + align:start position:0% +ever find a you know the um that it +evaluates a zero then you can accept but + + align:start position:0% +evaluates a zero then you can accept but + + + align:start position:0% +evaluates a zero then you can accept but +otherwise you just have to keep going + + align:start position:0% +otherwise you just have to keep going + + + align:start position:0% +otherwise you just have to keep going +and looking so showing recognizability + + align:start position:0% +and looking so showing recognizability + + + align:start position:0% +and looking so showing recognizability +is very simple but decidability is + + align:start position:0% +is very simple but decidability is + + + align:start position:0% +is very simple but decidability is +false okay now let's talk a little bit + + align:start position:0% +false okay now let's talk a little bit + + + align:start position:0% +false okay now let's talk a little bit +about encodings for touring machines um + + align:start position:0% +about encodings for touring machines um + + + align:start position:0% +about encodings for touring machines um +so uh we're going to be working + + align:start position:0% +so uh we're going to be working + + + align:start position:0% +so uh we're going to be working +encodings and touring machines so we're + + align:start position:0% +encodings and touring machines so we're + + + align:start position:0% +encodings and touring machines so we're +now going to be working with um uh + + align:start position:0% +now going to be working with um uh + + + align:start position:0% +now going to be working with um uh +touring machines going forward um we're + + align:start position:0% +touring machines going forward um we're + + + align:start position:0% +touring machines going forward um we're +going as I you know we're going + + align:start position:0% +going as I you know we're going + + + align:start position:0% +going as I you know we're going +to the input to those touring machines + + align:start position:0% +to the input to those touring machines + + + align:start position:0% +to the input to those touring machines +might be pols Might Be Strings they + + align:start position:0% +might be pols Might Be Strings they + + + align:start position:0% +might be pols Might Be Strings they +might be other things too we might want + + align:start position:0% +might be other things too we might want + + + align:start position:0% +might be other things too we might want +to feed autometer into the tourning + + align:start position:0% +to feed autometer into the tourning + + + align:start position:0% +to feed autometer into the tourning +machines so the touring machine can + + align:start position:0% +machines so the touring machine can + + + align:start position:0% +machines so the touring machine can +answer questions about the autometer + + align:start position:0% +answer questions about the autometer + + + align:start position:0% +answer questions about the autometer +well don't forget touring machines take + + align:start position:0% +well don't forget touring machines take + + + align:start position:0% +well don't forget touring machines take +as their input just strings so we have + + align:start position:0% +as their input just strings so we have + + + align:start position:0% +as their input just strings so we have +to think about how we're going to + + align:start position:0% +to think about how we're going to + + + align:start position:0% +to think about how we're going to +represent something more comp licated + + align:start position:0% +represent something more comp licated + + + align:start position:0% +represent something more comp licated +like an automaton as a string and I'm + + align:start position:0% +like an automaton as a string and I'm + + + align:start position:0% +like an automaton as a string and I'm +not going to get into the details of + + align:start position:0% +not going to get into the details of + + + align:start position:0% +not going to get into the details of +that you could spell it out in detail um + + align:start position:0% +that you could spell it out in detail um + + + align:start position:0% +that you could spell it out in detail um +but I think that's not too interesting + + align:start position:0% +but I think that's not too interesting + + + align:start position:0% +but I think that's not too interesting +to get into that we're just going to + + align:start position:0% +to get into that we're just going to + + + align:start position:0% +to get into that we're just going to +develop a notation that says if you have + + align:start position:0% +develop a notation that says if you have + + + align:start position:0% +develop a notation that says if you have +some object o it could be a polinomial + + align:start position:0% +some object o it could be a polinomial + + + align:start position:0% +some object o it could be a polinomial +it could be an automaton it could be a + + align:start position:0% +it could be an automaton it could be a + + + align:start position:0% +it could be an automaton it could be a +graph it could be whatever you're + + align:start position:0% +graph it could be whatever you're + + + align:start position:0% +graph it could be whatever you're +working with a table um I'm going to + + align:start position:0% +working with a table um I'm going to + + + align:start position:0% +working with a table um I'm going to +write that o in these brackets to mean + + align:start position:0% +write that o in these brackets to mean + + + align:start position:0% +write that o in these brackets to mean +an encoding of that object into a string + + align:start position:0% +an encoding of that object into a string + + + align:start position:0% +an encoding of that object into a string +and then you can feed the string into + + align:start position:0% +and then you can feed the string into + + + align:start position:0% +and then you can feed the string into +the touring + + align:start position:0% +the touring + + + align:start position:0% +the touring +machine okay um uh so that's how we're + + align:start position:0% +machine okay um uh so that's how we're + + + align:start position:0% +machine okay um uh so that's how we're +going to be thinking of presenting + + align:start position:0% +going to be thinking of presenting + + + align:start position:0% +going to be thinking of presenting +touring machines with more complicated + + align:start position:0% +touring machines with more complicated + + + align:start position:0% +touring machines with more complicated +objects and strings as input because + + align:start position:0% +objects and strings as input because + + + align:start position:0% +objects and strings as input because +we're just going to represent them as + + align:start position:0% +we're just going to represent them as + + + align:start position:0% +we're just going to represent them as +strings using some ways in which I'm + + align:start position:0% +strings using some ways in which I'm + + + align:start position:0% +strings using some ways in which I'm +sure you're all familiar and that's how + + align:start position:0% +sure you're all familiar and that's how + + + align:start position:0% +sure you're all familiar and that's how +you deal with representing stuff when + + align:start position:0% +you deal with representing stuff when + + + align:start position:0% +you deal with representing stuff when +you're you know have write your programs + + align:start position:0% +you're you know have write your programs + + + align:start position:0% +you're you know have write your programs +anyway um but just to make it formal and + + align:start position:0% +anyway um but just to make it formal and + + + align:start position:0% +anyway um but just to make it formal and +that's the way we're going to write it + + align:start position:0% +that's the way we're going to write it + + + align:start position:0% +that's the way we're going to write it +down in these brackets and if you have a + + align:start position:0% +down in these brackets and if you have a + + + align:start position:0% +down in these brackets and if you have a +list of several objects that you want to + + align:start position:0% +list of several objects that you want to + + + align:start position:0% +list of several objects that you want to +present together um to a touring machine + + align:start position:0% +present together um to a touring machine + + + align:start position:0% +present together um to a touring machine +we'll just write them together within + + align:start position:0% +we'll just write them together within + + + align:start position:0% +we'll just write them together within +brackets like this um now for writing + + align:start position:0% +brackets like this um now for writing + + + align:start position:0% +brackets like this um now for writing +touring machines + + align:start position:0% +touring machines + + + align:start position:0% +touring machines +down we're going to going forward going + + align:start position:0% +down we're going to going forward going + + + align:start position:0% +down we're going to going forward going +to be using high level English + + align:start position:0% +to be using high level English + + + align:start position:0% +to be using high level English +descriptions um we're not going to be + + align:start position:0% +descriptions um we're not going to be + + + align:start position:0% +descriptions um we're not going to be +worrying about managing the te like the + + align:start position:0% +worrying about managing the te like the + + + align:start position:0% +worrying about managing the te like the +stuff we've been doing up till now I'm + + align:start position:0% +stuff we've been doing up till now I'm + + + align:start position:0% +stuff we've been doing up till now I'm +not going to ask you to do it we're not + + align:start position:0% +not going to ask you to do it we're not + + + align:start position:0% +not going to ask you to do it we're not +going to do that anymore and I'm not + + align:start position:0% +going to do that anymore and I'm not + + + align:start position:0% +going to do that anymore and I'm not +going to ask you to do it managing where + + align:start position:0% +going to ask you to do it managing where + + + align:start position:0% +going to ask you to do it managing where +stuff goes on the tapes and all that + + align:start position:0% +stuff goes on the tapes and all that + + + align:start position:0% +stuff goes on the tapes and all that +stuff that's too low level um because + + align:start position:0% +stuff that's too low level um because + + + align:start position:0% +stuff that's too low level um because +really now that we have the church + + align:start position:0% +really now that we have the church + + + align:start position:0% +really now that we have the church +touring thesis we really interested in + + align:start position:0% +touring thesis we really interested in + + + align:start position:0% +touring thesis we really interested in +talking about algorithms we're not that + + align:start position:0% +talking about algorithms we're not that + + + align:start position:0% +talking about algorithms we're not that +interested talk talking about touring + + align:start position:0% +interested talk talking about touring + + + align:start position:0% +interested talk talking about touring +machines per se We Men algorithms um and + + align:start position:0% +machines per se We Men algorithms um and + + + align:start position:0% +machines per se We Men algorithms um and +what the power of computation is so um + + align:start position:0% +what the power of computation is so um + + + align:start position:0% +what the power of computation is so um +we're going to only be talking about + + align:start position:0% +we're going to only be talking about + + + align:start position:0% +we're going to only be talking about +touring machines now in a high higher + + align:start position:0% +touring machines now in a high higher + + + align:start position:0% +touring machines now in a high higher +level way and only when we need to prove + + align:start position:0% +level way and only when we need to prove + + + align:start position:0% +level way and only when we need to prove +something about uh capabilities we're + + align:start position:0% +something about uh capabilities we're + + + align:start position:0% +something about uh capabilities we're +going to come back to touring machines + + align:start position:0% +going to come back to touring machines + + + align:start position:0% +going to come back to touring machines +I'm going to be proving things you know + + align:start position:0% +I'm going to be proving things you know + + + align:start position:0% +I'm going to be proving things you know +about their limitations and so on so our + + align:start position:0% +about their limitations and so on so our + + + align:start position:0% +about their limitations and so on so our +notation for running touring machines is + + align:start position:0% +notation for running touring machines is + + + align:start position:0% +notation for running touring machines is +going to + + align:start position:0% +going to + + + align:start position:0% +going to +be basically going to put the touring + + align:start position:0% +be basically going to put the touring + + + align:start position:0% +be basically going to put the touring +machine inside these quotation marks and + + align:start position:0% +machine inside these quotation marks and + + + align:start position:0% +machine inside these quotation marks and +we're going to know + + align:start position:0% +we're going to know + + + align:start position:0% +we're going to know +that we could if in principle write out + + align:start position:0% +that we could if in principle write out + + + align:start position:0% +that we could if in principle write out +the touring machine in a precise way in + + align:start position:0% +the touring machine in a precise way in + + + align:start position:0% +the touring machine in a precise way in +terms of states and transition function + + align:start position:0% +terms of states and transition function + + + align:start position:0% +terms of states and transition function +and so on but we'll never actually go + + align:start position:0% +and so on but we'll never actually go + + + align:start position:0% +and so on but we'll never actually go +ahead and do that lengthy + + align:start position:0% +ahead and do that lengthy + + + align:start position:0% +ahead and do that lengthy +exercise um so quick check in + + align:start position:0% +exercise um so quick check in + + + align:start position:0% +exercise um so quick check in +here so one of the features well okay + + align:start position:0% +here so one of the features well okay + + + align:start position:0% +here so one of the features well okay +let me not give this away so if X and Y + + align:start position:0% +let me not give this away so if X and Y + + + align:start position:0% +let me not give this away so if X and Y +are + + align:start position:0% +are + + + align:start position:0% +are +strings you know I want to now have a + + align:start position:0% +strings you know I want to now have a + + + align:start position:0% +strings you know I want to now have a +way of presenting two strings as a + + align:start position:0% +way of presenting two strings as a + + + align:start position:0% +way of presenting two strings as a +single string as input to my machine + + align:start position:0% +single string as input to my machine + + + align:start position:0% +single string as input to my machine +because it's I always think of my + + align:start position:0% +because it's I always think of my + + + align:start position:0% +because it's I always think of my +machine is getting a single + + align:start position:0% +machine is getting a single + + + align:start position:0% +machine is getting a single +input so would you suggest one way of + + align:start position:0% +input so would you suggest one way of + + + align:start position:0% +input so would you suggest one way of +combining two strings into one which we + + align:start position:0% +combining two strings into one which we + + + align:start position:0% +combining two strings into one which we +would be a good encoding is just to + + align:start position:0% +would be a good encoding is just to + + + align:start position:0% +would be a good encoding is just to +concatenate those two strings + + align:start position:0% +concatenate those two strings + + + align:start position:0% +concatenate those two strings +together it's would it be that would + + align:start position:0% +together it's would it be that would + + + align:start position:0% +together it's would it be that would +would that be the way you would do it is + + align:start position:0% +would that be the way you would do it is + + + align:start position:0% +would that be the way you would do it is +that a good way to do it or or not such + + align:start position:0% +that a good way to do it or or not such + + + align:start position:0% +that a good way to do it or or not such +a good way to do it um so let's + + align:start position:0% +a good way to do it um so let's + + + align:start position:0% +a good way to do it um so let's +uh um let's see here + + align:start position:0% +uh um let's see here + + + align:start position:0% +uh um let's see here +I can get to that + + align:start position:0% + + + + align:start position:0% + +next and think of what you would want to + + align:start position:0% +next and think of what you would want to + + + align:start position:0% +next and think of what you would want to +have happened in a good + + align:start position:0% + + + + align:start position:0% + +encoding + + align:start position:0% +encoding + + + align:start position:0% +encoding +okay ready set + + align:start position:0% +okay ready set + + + align:start position:0% +okay ready set +sold uh share + + align:start position:0% +sold uh share + + + align:start position:0% +sold uh share +results yeah I think most of you got the + + align:start position:0% +results yeah I think most of you got the + + + align:start position:0% +results yeah I think most of you got the +idea that this is not a good way of + + align:start position:0% +idea that this is not a good way of + + + align:start position:0% +idea that this is not a good way of +combining two strings into one um + + align:start position:0% +combining two strings into one um + + + align:start position:0% +combining two strings into one um +because the problem is it's kind of + + align:start position:0% +because the problem is it's kind of + + + align:start position:0% +because the problem is it's kind of +ambiguous in a sense + + align:start position:0% +ambiguous in a sense + + + align:start position:0% +ambiguous in a sense +you know that you could if you combine + + align:start position:0% +you know that you could if you combine + + + align:start position:0% +you know that you could if you combine +two strings this way what's what's + + align:start position:0% +two strings this way what's what's + + + align:start position:0% +two strings this way what's what's +important in an encoding is that the + + align:start position:0% +important in an encoding is that the + + + align:start position:0% +important in an encoding is that the +machine when it gets the encoding it can + + align:start position:0% +machine when it gets the encoding it can + + + align:start position:0% +machine when it gets the encoding it can +decode them back into the original + + align:start position:0% +decode them back into the original + + + align:start position:0% +decode them back into the original +objects and if you're just going to be + + align:start position:0% +objects and if you're just going to be + + + align:start position:0% +objects and if you're just going to be +sticking the two strings together you + + align:start position:0% +sticking the two strings together you + + + align:start position:0% +sticking the two strings together you +don't know where one string ends and the + + align:start position:0% +don't know where one string ends and the + + + align:start position:0% +don't know where one string ends and the +next string begins and so it's not going + + align:start position:0% +next string begins and so it's not going + + + align:start position:0% +next string begins and so it's not going +to be a good way of combining things you + + align:start position:0% +to be a good way of combining things you + + + align:start position:0% +to be a good way of combining things you +you should F find a little bit more + + align:start position:0% +you should F find a little bit more + + + align:start position:0% +you should F find a little bit more +clever way of either introducing another + + align:start position:0% +clever way of either introducing another + + + align:start position:0% +clever way of either introducing another +symbol or doing something a little bit + + align:start position:0% +symbol or doing something a little bit + + + align:start position:0% +symbol or doing something a little bit +more sophisticated which allow you to be + + align:start position:0% +more sophisticated which allow you to be + + + align:start position:0% +more sophisticated which allow you to be +a ble to do the decoding as well as the + + align:start position:0% +a ble to do the decoding as well as the + + + align:start position:0% +a ble to do the decoding as well as the +encoding in a unique + + align:start position:0% +encoding in a unique + + + align:start position:0% +encoding in a unique +way okay so uh getting back to that + + align:start position:0% +way okay so uh getting back to that + + + align:start position:0% +way okay so uh getting back to that +notation for turing machine so here is + + align:start position:0% +notation for turing machine so here is + + + align:start position:0% +notation for turing machine so here is +the machine we've already seen once + + align:start position:0% +the machine we've already seen once + + + align:start position:0% +the machine we've already seen once +before uh for a to the k b to the K C to + + align:start position:0% +before uh for a to the k b to the K C to + + + align:start position:0% +before uh for a to the k b to the K C to +the K I would write it now more simply + + align:start position:0% +the K I would write it now more simply + + + align:start position:0% +the K I would write it now more simply +than managing all of the tapes that we + + align:start position:0% +than managing all of the tapes that we + + + align:start position:0% +than managing all of the tapes that we +had the first time around which we did + + align:start position:0% +had the first time around which we did + + + align:start position:0% +had the first time around which we did +last lecture I would just say given an + + align:start position:0% +last lecture I would just say given an + + + align:start position:0% +last lecture I would just say given an +input W check if W is of the right form + + align:start position:0% +input W check if W is of the right form + + + align:start position:0% +input W check if W is of the right form +with the things in the right order + + align:start position:0% +with the things in the right order + + + align:start position:0% +with the things in the right order +reject if it's not count the number of + + align:start position:0% +reject if it's not count the number of + + + align:start position:0% +reject if it's not count the number of +A's BS and C's and W except if all the + + align:start position:0% +A's BS and C's and W except if all the + + + align:start position:0% +A's BS and C's and W except if all the +counts are equal and reject if not we're + + align:start position:0% +counts are equal and reject if not we're + + + align:start position:0% +counts are equal and reject if not we're +not going to be that's going to be good + + align:start position:0% +not going to be that's going to be good + + + align:start position:0% +not going to be that's going to be good +enough to be writing things at that + + align:start position:0% +enough to be writing things at that + + + align:start position:0% +enough to be writing things at that +higher level when you're going to be + + align:start position:0% +higher level when you're going to be + + + align:start position:0% +higher level when you're going to be +writing your algorithm descriptions you + + align:start position:0% +writing your algorithm descriptions you + + + align:start position:0% +writing your algorithm descriptions you +just have to make sure that whatever + + align:start position:0% +just have to make sure that whatever + + + align:start position:0% +just have to make sure that whatever +you're doing you can Implement um you + + align:start position:0% +you're doing you can Implement um you + + + align:start position:0% +you're doing you can Implement um you +know you you can't make uh you don't you + + align:start position:0% +know you you can't make uh you don't you + + + align:start position:0% +know you you can't make uh you don't you +you don't want to be doing tests which + + align:start position:0% +you don't want to be doing tests which + + + align:start position:0% +you don't want to be doing tests which +are impossible or doing infinite + + align:start position:0% +are impossible or doing infinite + + + align:start position:0% +are impossible or doing infinite +infinitely much work in one stage that's + + align:start position:0% +infinitely much work in one stage that's + + + align:start position:0% +infinitely much work in one stage that's +not good um but as long as it's clear + + align:start position:0% +not good um but as long as it's clear + + + align:start position:0% +not good um but as long as it's clear +that what you doing has doing only a + + align:start position:0% +that what you doing has doing only a + + + align:start position:0% +that what you doing has doing only a +finite amount of work in every stage and + + align:start position:0% +finite amount of work in every stage and + + + align:start position:0% +finite amount of work in every stage and +it's something that you could really + + align:start position:0% +it's something that you could really + + + align:start position:0% +it's something that you could really +Implement you can write it at a high in + + align:start position:0% +Implement you can write it at a high in + + + align:start position:0% +Implement you can write it at a high in +a high level um okay I wanted to spend a + + align:start position:0% +a high level um okay I wanted to spend a + + + align:start position:0% +a high level um okay I wanted to spend a +few minutes talking about problem set + + align:start position:0% +few minutes talking about problem set + + + align:start position:0% +few minutes talking about problem set +two but we a little bit running out of + + align:start position:0% +two but we a little bit running out of + + + align:start position:0% +two but we a little bit running out of +time here um uh in particular there was + + align:start position:0% +time here um uh in particular there was + + + align:start position:0% +time here um uh in particular there was +this problem number five where you show + + align:start position:0% +this problem number five where you show + + + align:start position:0% +this problem number five where you show +that language of touring recognizable if + + align:start position:0% +that language of touring recognizable if + + + align:start position:0% +that language of touring recognizable if +and only if there's a decidable D um + + align:start position:0% +and only if there's a decidable D um + + + align:start position:0% +and only if there's a decidable D um +where C is touring recognizable where D + + align:start position:0% +where C is touring recognizable where D + + + align:start position:0% +where C is touring recognizable where D +is now collection of pairs we got some + + align:start position:0% +is now collection of pairs we got some + + + align:start position:0% +is now collection of pairs we got some +questions about the notation which I've + + align:start position:0% +questions about the notation which I've + + + align:start position:0% +questions about the notation which I've +hope hopefully answered now so um + + align:start position:0% +hope hopefully answered now so um + + + align:start position:0% +hope hopefully answered now so um +C uh is a set of x's such that there + + align:start position:0% +C uh is a set of x's such that there + + + align:start position:0% +C uh is a set of x's such that there +exists a string you can pair it with so + + align:start position:0% +exists a string you can pair it with so + + + align:start position:0% +exists a string you can pair it with so +that the string X Y is in + + align:start position:0% +that the string X Y is in + + + align:start position:0% +that the string X Y is in +D um let me try to give you a picture of + + align:start position:0% +D um let me try to give you a picture of + + + align:start position:0% +D um let me try to give you a picture of +that uh + + align:start position:0% +that uh + + + align:start position:0% +that uh +um so I'm going to think of d as a + + align:start position:0% +um so I'm going to think of d as a + + + align:start position:0% +um so I'm going to think of d as a +collection of pairs of strings and it + + align:start position:0% +collection of pairs of strings and it + + + align:start position:0% +collection of pairs of strings and it +might be helpful to think of D kind of + + align:start position:0% +might be helpful to think of D kind of + + + align:start position:0% +might be helpful to think of D kind of +you know on the axes here so if we have + + align:start position:0% +you know on the axes here so if we have + + + align:start position:0% +you know on the axes here so if we have +a pair of strings XY which I have not + + align:start position:0% +a pair of strings XY which I have not + + + align:start position:0% +a pair of strings XY which I have not +yet packaged into a single string I'm + + align:start position:0% +yet packaged into a single string I'm + + + align:start position:0% +yet packaged into a single string I'm +thinking of them as a pair of two + + align:start position:0% +thinking of them as a pair of two + + + align:start position:0% +thinking of them as a pair of two +objects at this moment uh think of d as + + align:start position:0% +objects at this moment uh think of d as + + + align:start position:0% +objects at this moment uh think of d as +so you know Ju Just the X part is just + + align:start position:0% +so you know Ju Just the X part is just + + + align:start position:0% +so you know Ju Just the X part is just +below here on the x-axis um D you might + + align:start position:0% +below here on the x-axis um D you might + + + align:start position:0% +below here on the x-axis um D you might +want to think just conceptually want to + + align:start position:0% +want to think just conceptually want to + + + align:start position:0% +want to think just conceptually want to +think of it as a collection of pairs so + + align:start position:0% +think of it as a collection of pairs so + + + align:start position:0% +think of it as a collection of pairs so +it's like a subset of all of these pairs + + align:start position:0% +it's like a subset of all of these pairs + + + align:start position:0% +it's like a subset of all of these pairs +and C + + align:start position:0% +and C + + + align:start position:0% +and C +is all of the the X's that correspond to + + align:start position:0% +is all of the the X's that correspond to + + + align:start position:0% +is all of the the X's that correspond to +any pair in here um sometimes we call + + align:start position:0% +any pair in here um sometimes we call + + + align:start position:0% +any pair in here um sometimes we call +that the projection because it's all the + + align:start position:0% +that the projection because it's all the + + + align:start position:0% +that the projection because it's all the +things that are below or the shadow if + + align:start position:0% +things that are below or the shadow if + + + align:start position:0% +things that are below or the shadow if +you had a light sitting up here it's all + + align:start position:0% +you had a light sitting up here it's all + + + align:start position:0% +you had a light sitting up here it's all +the things that are kind of underneath a + + align:start position:0% +the things that are kind of underneath a + + + align:start position:0% +the things that are kind of underneath a +D um so I've written C here kind of a + + align:start position:0% +D um so I've written C here kind of a + + + align:start position:0% +D um so I've written C here kind of a +little thicker if you can see that so + + align:start position:0% +little thicker if you can see that so + + + align:start position:0% +little thicker if you can see that so +that's the C language and + + align:start position:0% +that's the C language and + + + align:start position:0% +that's the C language and +um what you're going to what there's two + + align:start position:0% +um what you're going to what there's two + + + align:start position:0% +um what you're going to what there's two +directions here one is a lot easier than + + align:start position:0% +directions here one is a lot easier than + + + align:start position:0% +directions here one is a lot easier than +the other if I give you a decidable + + align:start position:0% +the other if I give you a decidable + + + align:start position:0% +the other if I give you a decidable +d and I want to test whether something's + + align:start position:0% +d and I want to test whether something's + + + align:start position:0% +d and I want to test whether something's +in C so I give you an X I want to know + + align:start position:0% +in C so I give you an X I want to know + + + align:start position:0% +in C so I give you an X I want to know +is it is x in + + align:start position:0% +is it is x in + + + align:start position:0% +is it is x in +C well you now have to test is there + + align:start position:0% +C well you now have to test is there + + + align:start position:0% +C well you now have to test is there +some y that I can pair with X where the + + align:start position:0% +some y that I can pair with X where the + + + align:start position:0% +some y that I can pair with X where the +pair is in + + align:start position:0% +pair is in + + + align:start position:0% +pair is in +D um so you know you can start looking + + align:start position:0% +D um so you know you can start looking + + + align:start position:0% +D um so you know you can start looking +for that y if you ever find one you know + + align:start position:0% +for that y if you ever find one you know + + + align:start position:0% +for that y if you ever find one you know +that X is in C there are infinitely many + + align:start position:0% +that X is in C there are infinitely many + + + align:start position:0% +that X is in C there are infinitely many +y to to look for but don't forget you + + align:start position:0% +y to to look for but don't forget you + + + align:start position:0% +y to to look for but don't forget you +know you're only looking for a + + align:start position:0% +know you're only looking for a + + + align:start position:0% +know you're only looking for a +recognizer for + + align:start position:0% +recognizer for + + + align:start position:0% +recognizer for +C so you know on the rejecting side + + align:start position:0% +C so you know on the rejecting side + + + align:start position:0% +C so you know on the rejecting side +you're allowed to go forever so I I'm + + align:start position:0% +you're allowed to go forever so I I'm + + + align:start position:0% +you're allowed to go forever so I I'm +kind of giving you a way to think about + + align:start position:0% +kind of giving you a way to think about + + + align:start position:0% +kind of giving you a way to think about +the easy Direction the hard Direction um + + align:start position:0% +the easy Direction the hard Direction um + + + align:start position:0% +the easy Direction the hard Direction um +you need to think about um how are you + + align:start position:0% +you need to think about um how are you + + + align:start position:0% +you need to think about um how are you +going to come up with that decidable + + align:start position:0% +going to come up with that decidable + + + align:start position:0% +going to come up with that decidable +date if I give you C you have to find a + + align:start position:0% +date if I give you C you have to find a + + + align:start position:0% +date if I give you C you have to find a +decidable d and now you're you're + + align:start position:0% +decidable d and now you're you're + + + align:start position:0% +decidable d and now you're you're +bringing something down lower you're + + align:start position:0% +bringing something down lower you're + + + align:start position:0% +bringing something down lower you're +starting with a recognizing recognizable + + align:start position:0% +starting with a recognizing recognizable + + + align:start position:0% +starting with a recognizing recognizable +language and a decidable language which + + align:start position:0% +language and a decidable language which + + + align:start position:0% +language and a decidable language which +is going to sort of be counterpart to + + align:start position:0% +is going to sort of be counterpart to + + + align:start position:0% +is going to sort of be counterpart to +that in a sense is a simpler language + + align:start position:0% +that in a sense is a simpler language + + + align:start position:0% +that in a sense is a simpler language +and the way it becomes simpler is that Y + + align:start position:0% +and the way it becomes simpler is that Y + + + align:start position:0% +and the way it becomes simpler is that Y +is going to help you determine whether X + + align:start position:0% +is going to help you determine whether X + + + align:start position:0% +is going to help you determine whether X +is in + + align:start position:0% +is in + + + align:start position:0% +is in +C um and I guess the thing that you + + align:start position:0% +C um and I guess the thing that you + + + align:start position:0% +C um and I guess the thing that you +should I'll leave you with is and maybe + + align:start position:0% +should I'll leave you with is and maybe + + + align:start position:0% +should I'll leave you with is and maybe +we can talk about this a little bit more + + align:start position:0% +we can talk about this a little bit more + + + align:start position:0% +we can talk about this a little bit more +uh on Tuesday I'll I'll try to leave it + + align:start position:0% +uh on Tuesday I'll I'll try to leave it + + + align:start position:0% +uh on Tuesday I'll I'll try to leave it +a little bit more time + + align:start position:0% +a little bit more time + + + align:start position:0% +a little bit more time +uh if you want to test if something's in + + align:start position:0% +uh if you want to test if something's in + + + align:start position:0% +uh if you want to test if something's in +c x is in C but I don't want to let you + + align:start position:0% +c x is in C but I don't want to let you + + + align:start position:0% +c x is in C but I don't want to let you +go forever anymore because I want to be + + align:start position:0% +go forever anymore because I want to be + + + align:start position:0% +go forever anymore because I want to be +a decidable language and I'm going to + + align:start position:0% +a decidable language and I'm going to + + + align:start position:0% +a decidable language and I'm going to +use y to help you what information would + + align:start position:0% +use y to help you what information would + + + align:start position:0% +use y to help you what information would +help you guarantee you get the right + + align:start position:0% +help you guarantee you get the right + + + align:start position:0% +help you guarantee you get the right +answer for X being in C um but that you + + align:start position:0% +answer for X being in C um but that you + + + align:start position:0% +answer for X being in C um but that you +would um have to be sure you're getting + + align:start position:0% +would um have to be sure you're getting + + + align:start position:0% +would um have to be sure you're getting +the right answer so it's you know why + + align:start position:0% +the right answer so it's you know why + + + align:start position:0% +the right answer so it's you know why +could just be the answer but then you + + align:start position:0% +could just be the answer but then you + + + align:start position:0% +could just be the answer but then you +know you don't know that that's you you + + align:start position:0% +know you don't know that that's you you + + + align:start position:0% +know you don't know that that's you you +have to be convinced that you have the + + align:start position:0% +have to be convinced that you have the + + + align:start position:0% +have to be convinced that you have the +right answer you know why just saying + + align:start position:0% +right answer you know why just saying + + + align:start position:0% +right answer you know why just saying +what it is I mean you could why could + + align:start position:0% +what it is I mean you could why could + + + align:start position:0% +what it is I mean you could why could +say it that X is in D even when it's not + + align:start position:0% +say it that X is in D even when it's not + + + align:start position:0% +say it that X is in D even when it's not +true X is in C even when it's not true + + align:start position:0% +true X is in C even when it's not true + + + align:start position:0% +true X is in C even when it's not true +but so what information would allow you + + align:start position:0% +but so what information would allow you + + + align:start position:0% +but so what information would allow you +to check that X is in C what would be + + align:start position:0% +to check that X is in C what would be + + + align:start position:0% +to check that X is in C what would be +helpful information to check the x's and + + align:start position:0% +helpful information to check the x's and + + + align:start position:0% +helpful information to check the x's and +C where you would avoid ever having to + + align:start position:0% +C where you would avoid ever having to + + + align:start position:0% +C where you would avoid ever having to +go + + align:start position:0% +go + + + align:start position:0% +go +forever little bit too rushed here to + + align:start position:0% +forever little bit too rushed here to + + + align:start position:0% +forever little bit too rushed here to +for that to be helpful anyway let's just + + align:start position:0% +for that to be helpful anyway let's just + + + align:start position:0% +for that to be helpful anyway let's just +uh conclude what we've done um just + + align:start position:0% +uh conclude what we've done um just + + + align:start position:0% +uh conclude what we've done um just +brief summary here + + align:start position:0% +brief summary here + + + align:start position:0% +brief summary here +um and I I I don't want to + + align:start position:0% +um and I I I don't want to + + + align:start position:0% +um and I I I don't want to +uh um keep you in keep you over time so + + align:start position:0% +uh um keep you in keep you over time so + + + align:start position:0% +uh um keep you in keep you over time so +I'll just leave this up on the board um + + align:start position:0% +I'll just leave this up on the board um + + + align:start position:0% +I'll just leave this up on the board um +I will uh + + align:start position:0% +I will uh + + + align:start position:0% +I will uh +um uh see if there's any so what the + + align:start position:0% +um uh see if there's any so what the + + + align:start position:0% +um uh see if there's any so what the +lecture is over uh and you can take off + + align:start position:0% +lecture is over uh and you can take off + + + align:start position:0% +lecture is over uh and you can take off +as you wish um I will stick around for a + + align:start position:0% +as you wish um I will stick around for a + + + align:start position:0% +as you wish um I will stick around for a +couple of minutes I have another meeting + + align:start position:0% +couple of minutes I have another meeting + + + align:start position:0% +couple of minutes I have another meeting +soon um but I'll answer try to answer + + align:start position:0% +soon um but I'll answer try to answer + + + align:start position:0% +soon um but I'll answer try to answer +some + + align:start position:0% +some + + + align:start position:0% +some +chats uh + + align:start position:0% + + + + align:start position:0% + +all right um people are commenting about + + align:start position:0% +all right um people are commenting about + + + align:start position:0% +all right um people are commenting about +this movie about touring the imitation + + align:start position:0% +this movie about touring the imitation + + + align:start position:0% +this movie about touring the imitation +game uh you know if you haven't seen + + align:start position:0% +game uh you know if you haven't seen + + + align:start position:0% +game uh you know if you haven't seen +that I recommend it + + align:start position:0% +that I recommend it + + + align:start position:0% +that I recommend it +um um and + + align:start position:0% +um um and + + + align:start position:0% +um um and +uh is it a good idea to make y to be + + align:start position:0% +uh is it a good idea to make y to be + + + align:start position:0% +uh is it a good idea to make y to be +equal to the repeated Loop stram H I'm + + align:start position:0% +equal to the repeated Loop stram H I'm + + + align:start position:0% +equal to the repeated Loop stram H I'm +not sure about that uh thank you for the + + align:start position:0% +not sure about that uh thank you for the + + + align:start position:0% +not sure about that uh thank you for the +uh thank you everybody for sending your + + align:start position:0% +uh thank you everybody for sending your + + + align:start position:0% +uh thank you everybody for sending your +kind notes um + + align:start position:0% + + + + align:start position:0% + +is church Turing thesis the question is + + align:start position:0% +is church Turing thesis the question is + + + align:start position:0% +is church Turing thesis the question is +is it in the book yes it's in the book + + align:start position:0% +is it in the book yes it's in the book + + + align:start position:0% +is it in the book yes it's in the book +kind of similar to what I've already + + align:start position:0% +kind of similar to what I've already + + + align:start position:0% +kind of similar to what I've already +said but + + align:start position:0% +said but + + + align:start position:0% +said but +yes + + align:start position:0% + + + + align:start position:0% + +um okay this is a good question here um + + align:start position:0% +um okay this is a good question here um + + + align:start position:0% +um okay this is a good question here um +the church touring thesis somebody asked + + align:start position:0% +the church touring thesis somebody asked + + + align:start position:0% +the church touring thesis somebody asked +me is it proved in the book there's + + align:start position:0% +me is it proved in the book there's + + + align:start position:0% +me is it proved in the book there's +nothing to prove + + align:start position:0% +nothing to prove + + + align:start position:0% +nothing to prove +the church touring thesis is an + + align:start position:0% +the church touring thesis is an + + + align:start position:0% +the church touring thesis is an +equivalence between the intuitive and + + align:start position:0% +equivalence between the intuitive and + + + align:start position:0% +equivalence between the intuitive and +the formal you can't prove something + + align:start position:0% +the formal you can't prove something + + + align:start position:0% +the formal you can't prove something +like that um you can just make it's + + align:start position:0% +like that um you can just make it's + + + align:start position:0% +like that um you can just make it's +really in a sense a hypothesis that the + + align:start position:0% +really in a sense a hypothesis that the + + + align:start position:0% +really in a sense a hypothesis that the +only thing you'll ever be able to + + align:start position:0% +only thing you'll ever be able to + + + align:start position:0% +only thing you'll ever be able to +compute um is something that you can do + + align:start position:0% +compute um is something that you can do + + + align:start position:0% +compute um is something that you can do +with a touring machine um I mean that + + align:start position:0% +with a touring machine um I mean that + + + align:start position:0% +with a touring machine um I mean that +has something to do with the nature of + + align:start position:0% +has something to do with the nature of + + + align:start position:0% +has something to do with the nature of +the physical world and I'm sure I don't + + align:start position:0% +the physical world and I'm sure I don't + + + align:start position:0% +the physical world and I'm sure I don't +really think that's what people had in + + align:start position:0% +really think that's what people had in + + + align:start position:0% +really think that's what people had in +mind it's that you know the the kinds of + + align:start position:0% +mind it's that you know the the kinds of + + + align:start position:0% +mind it's that you know the the kinds of +things that we nor think of being able + + align:start position:0% +things that we nor think of being able + + + align:start position:0% +things that we nor think of being able +to do with a with a rest with a + + align:start position:0% +to do with a with a rest with a + + + align:start position:0% +to do with a with a rest with a +procedure mathematically is exactly the + + align:start position:0% +procedure mathematically is exactly the + + + align:start position:0% +procedure mathematically is exactly the +kinds of things that you can do with a + + align:start position:0% +kinds of things that you can do with a + + + align:start position:0% +kinds of things that you can do with a +touring machine + + align:start position:0% +touring machine + + + align:start position:0% +touring machine +um so somebody's pointing I will trying + + align:start position:0% +um so somebody's pointing I will trying + + + align:start position:0% +um so somebody's pointing I will trying +to be helpful here maybe these folks are + + align:start position:0% +to be helpful here maybe these folks are + + + align:start position:0% +to be helpful here maybe these folks are +asking about equivalence of various + + align:start position:0% +asking about equivalence of various + + + align:start position:0% +asking about equivalence of various +different computation models being + + align:start position:0% +different computation models being + + + align:start position:0% +different computation models being +proved in the book not the church during + + align:start position:0% +proved in the book not the church during + + + align:start position:0% +proved in the book not the church during +thesis itself well I mean that's the the + + align:start position:0% +thesis itself well I mean that's the the + + + align:start position:0% +thesis itself well I mean that's the the +things that we proved in lecture are + + align:start position:0% +things that we proved in lecture are + + + align:start position:0% +things that we proved in lecture are +also proved in the book um about the + + align:start position:0% +also proved in the book um about the + + + align:start position:0% +also proved in the book um about the +equivalent of single tape machines + + align:start position:0% +equivalent of single tape machines + + + align:start position:0% +equivalent of single tape machines +multi-tape machines non-deterministic + + align:start position:0% +multi-tape machines non-deterministic + + + align:start position:0% +multi-tape machines non-deterministic +machines um those are all proved in the + + align:start position:0% +machines um those are all proved in the + + + align:start position:0% +machines um those are all proved in the +book we don't those I mean there's lots + + align:start position:0% +book we don't those I mean there's lots + + + align:start position:0% +book we don't those I mean there's lots +of models out there so we could spend a + + align:start position:0% +of models out there so we could spend a + + + align:start position:0% +of models out there so we could spend a +lot of time proving equivalences um and + + align:start position:0% +lot of time proving equivalences um and + + + align:start position:0% +lot of time proving equivalences um and +there are books that do spend a lot of + + align:start position:0% +there are books that do spend a lot of + + + align:start position:0% +there are books that do spend a lot of +time proving equivalences but I + + align:start position:0% +time proving equivalences but I + + + align:start position:0% +time proving equivalences but I +think you know + + align:start position:0% +think you know + + + align:start position:0% +think you know +uh we yeah I think what we've given is + + align:start position:0% +uh we yeah I think what we've given is + + + align:start position:0% +uh we yeah I think what we've given is +probably enough + + align:start position:0% +probably enough + + + align:start position:0% +probably enough +um + + align:start position:0% +um + + + align:start position:0% +um +uh so somebody that's a good question if + + align:start position:0% +uh so somebody that's a good question if + + + align:start position:0% +uh so somebody that's a good question if +if you give an + + align:start position:0% +if you give an + + + align:start position:0% +if you give an +algorithm okay if you give an algorithm + + align:start position:0% +algorithm okay if you give an algorithm + + + align:start position:0% +algorithm okay if you give an algorithm +you don't need to give the actual + + align:start position:0% +you don't need to give the actual + + + align:start position:0% +you don't need to give the actual +machine uh going forward unless somebody + + align:start position:0% +machine uh going forward unless somebody + + + align:start position:0% +machine uh going forward unless somebody +unless you're explicitly asked to um uh + + align:start position:0% +unless you're explicitly asked to um uh + + + align:start position:0% +unless you're explicitly asked to um uh +but yes you don't you don't have to give + + align:start position:0% +but yes you don't you don't have to give + + + align:start position:0% +but yes you don't you don't have to give +um the states and transitions anymore + + align:start position:0% + + + + align:start position:0% + +um okay so it's a little after four I + + align:start position:0% +um okay so it's a little after four I + + + align:start position:0% +um okay so it's a little after four I +think we're going + + align:start position:0% +think we're going + + + align:start position:0% +think we're going +to I think I'm going to move on to my + + align:start position:0% +to I think I'm going to move on to my + + + align:start position:0% +to I think I'm going to move on to my +next meeting uh so I uh thank you for + + align:start position:0% +next meeting uh so I uh thank you for + + + align:start position:0% +next meeting uh so I uh thank you for +being here and I will see you um on + + align:start position:0% +being here and I will see you um on + + + align:start position:0% +being here and I will see you um on +Tuesday \ No newline at end of file diff --git a/Tpaw_dE9LyY.txt b/Tpaw_dE9LyY.txt new file mode 100644 index 0000000000000000000000000000000000000000..fa4004820d3accde79ff1080f86a36b98f62cf68 --- /dev/null +++ b/Tpaw_dE9LyY.txt @@ -0,0 +1,675 @@ +align:start position:0% + +I'm pleased to know that our colleagues + + align:start position:0% +I'm pleased to know that our colleagues + + + align:start position:0% +I'm pleased to know that our colleagues +at MIT are reaching out to people all + + align:start position:0% +at MIT are reaching out to people all + + + align:start position:0% +at MIT are reaching out to people all +over the world to engage them in this + + align:start position:0% +over the world to engage them in this + + + align:start position:0% +over the world to engage them in this +important discussion about the future of + + align:start position:0% +important discussion about the future of + + + align:start position:0% +important discussion about the future of +work we are launching our own future of + + align:start position:0% +work we are launching our own future of + + + align:start position:0% +work we are launching our own future of +work initiative here at the io and this + + align:start position:0% +work initiative here at the io and this + + + align:start position:0% +work initiative here at the io and this +course will fit very well with our + + align:start position:0% +course will fit very well with our + + + align:start position:0% +course will fit very well with our +initiative look I think that our future + + align:start position:0% +initiative look I think that our future + + + align:start position:0% +initiative look I think that our future +of work initiative responds to to two + + align:start position:0% +of work initiative responds to to two + + + align:start position:0% +of work initiative responds to to two +essential things one's got to do with + + align:start position:0% +essential things one's got to do with + + + align:start position:0% +essential things one's got to do with +need one's got to do with opportunity uh + + align:start position:0% +need one's got to do with opportunity uh + + + align:start position:0% +need one's got to do with opportunity uh +the need comes from the fact and we're + + align:start position:0% +the need comes from the fact and we're + + + align:start position:0% +the need comes from the fact and we're +all conscious of this in our everyday + + align:start position:0% +all conscious of this in our everyday + + + align:start position:0% +all conscious of this in our everyday +lives that there is massive change + + align:start position:0% +lives that there is massive change + + + align:start position:0% +lives that there is massive change +taking place in the world of work + + align:start position:0% +taking place in the world of work + + + align:start position:0% +taking place in the world of work +transformative change at a Pac and at a + + align:start position:0% +transformative change at a Pac and at a + + + align:start position:0% +transformative change at a Pac and at a +depth that we don't really have + + align:start position:0% +depth that we don't really have + + + align:start position:0% +depth that we don't really have +experience of in the past so we think + + align:start position:0% +experience of in the past so we think + + + align:start position:0% +experience of in the past so we think +that we need to study these big changes + + align:start position:0% +that we need to study these big changes + + + align:start position:0% +that we need to study these big changes +to understand them better as a way of + + align:start position:0% +to understand them better as a way of + + + align:start position:0% +to understand them better as a way of +working out what we should do about them + + align:start position:0% +working out what we should do about them + + + align:start position:0% +working out what we should do about them +uh in order order to make sure that the + + align:start position:0% +uh in order order to make sure that the + + + align:start position:0% +uh in order order to make sure that the +world of work responds to the ilo's + + align:start position:0% +world of work responds to the ilo's + + + align:start position:0% +world of work responds to the ilo's +ideas of social justice fairness at work + + align:start position:0% +ideas of social justice fairness at work + + + align:start position:0% +ideas of social justice fairness at work +and then there is the opportunity and + + align:start position:0% +and then there is the opportunity and + + + align:start position:0% +and then there is the opportunity and +the opportunity comes from the fact that + + align:start position:0% +the opportunity comes from the fact that + + + align:start position:0% +the opportunity comes from the fact that +in in three years time in + + align:start position:0% +in in three years time in + + + align:start position:0% +in in three years time in +2019 the io will celebrate its 100th + + align:start position:0% +2019 the io will celebrate its 100th + + + align:start position:0% +2019 the io will celebrate its 100th +birthday it's centinary so what better + + align:start position:0% +birthday it's centinary so what better + + + align:start position:0% +birthday it's centinary so what better +opportunity they don't come around that + + align:start position:0% +opportunity they don't come around that + + + align:start position:0% +opportunity they don't come around that +frequently what better opportunity than + + align:start position:0% +frequently what better opportunity than + + + align:start position:0% +frequently what better opportunity than +that to have this in-depth reflection + + align:start position:0% +that to have this in-depth reflection + + + align:start position:0% +that to have this in-depth reflection +about the direction that the world of + + align:start position:0% +about the direction that the world of + + + align:start position:0% +about the direction that the world of +work is taking and what we can can do to + + align:start position:0% +work is taking and what we can can do to + + + align:start position:0% +work is taking and what we can can do to +shape it to move it towards these ideals + + align:start position:0% +shape it to move it towards these ideals + + + align:start position:0% +shape it to move it towards these ideals +of social justice we are proposing uh to + + align:start position:0% +of social justice we are proposing uh to + + + align:start position:0% +of social justice we are proposing uh to +Our member states that they structure + + align:start position:0% +Our member states that they structure + + + align:start position:0% +Our member states that they structure +their National dialogues around four + + align:start position:0% +their National dialogues around four + + + align:start position:0% +their National dialogues around four +conversations and very quickly uh one is + + align:start position:0% +conversations and very quickly uh one is + + + align:start position:0% +conversations and very quickly uh one is +to do with work and Society sounds a bit + + align:start position:0% +to do with work and Society sounds a bit + + + align:start position:0% +to do with work and Society sounds a bit +philosophical but I think there are some + + align:start position:0% +philosophical but I think there are some + + + align:start position:0% +philosophical but I think there are some +really deep questions out there about + + align:start position:0% +really deep questions out there about + + + align:start position:0% +really deep questions out there about +what work means to each and every one of + + align:start position:0% +what work means to each and every one of + + + align:start position:0% +what work means to each and every one of +us in terms not only of earning our + + align:start position:0% +us in terms not only of earning our + + + align:start position:0% +us in terms not only of earning our +living but also of self-realization of + + align:start position:0% +living but also of self-realization of + + + align:start position:0% +living but also of self-realization of +our you know what our lives mean and and + + align:start position:0% +our you know what our lives mean and and + + + align:start position:0% +our you know what our lives mean and and +how we want to proceed with them + + align:start position:0% +how we want to proceed with them + + + align:start position:0% +how we want to proceed with them +secondly and it's the most frequently + + align:start position:0% +secondly and it's the most frequently + + + align:start position:0% +secondly and it's the most frequently +Asked question that I at least get about + + align:start position:0% +Asked question that I at least get about + + + align:start position:0% +Asked question that I at least get about +the future is decent work of Tomorrow + + align:start position:0% +the future is decent work of Tomorrow + + + align:start position:0% +the future is decent work of Tomorrow +the decent jobs of tomorrow where are + + align:start position:0% +the decent jobs of tomorrow where are + + + align:start position:0% +the decent jobs of tomorrow where are +those jobs coming from we're having to + + align:start position:0% +those jobs coming from we're having to + + + align:start position:0% +those jobs coming from we're having to +create 40 million jobs every year just + + align:start position:0% +create 40 million jobs every year just + + + align:start position:0% +create 40 million jobs every year just +to absorb the new people coming onto the + + align:start position:0% +to absorb the new people coming onto the + + + align:start position:0% +to absorb the new people coming onto the +labor markets uh and frankly we're not + + align:start position:0% +labor markets uh and frankly we're not + + + align:start position:0% +labor markets uh and frankly we're not +able to do it at the moment so we have + + align:start position:0% +able to do it at the moment so we have + + + align:start position:0% +able to do it at the moment so we have +to be able to discuss the nature and the + + align:start position:0% +to be able to discuss the nature and the + + + align:start position:0% +to be able to discuss the nature and the +origin of work in the future + + align:start position:0% +origin of work in the future + + + align:start position:0% +origin of work in the future +the third item is about the organization + + align:start position:0% +the third item is about the organization + + + align:start position:0% +the third item is about the organization +the organization of work and production + + align:start position:0% +the organization of work and production + + + align:start position:0% +the organization of work and production +you know we're seeing the digital + + align:start position:0% +you know we're seeing the digital + + + align:start position:0% +you know we're seeing the digital +economy take off we're seeing the way + + align:start position:0% +economy take off we're seeing the way + + + align:start position:0% +economy take off we're seeing the way +that the internet is mediating work in + + align:start position:0% +that the internet is mediating work in + + + align:start position:0% +that the internet is mediating work in +entirely new ways uh maybe the + + align:start position:0% +entirely new ways uh maybe the + + + align:start position:0% +entirely new ways uh maybe the +Enterprise is going to look very + + align:start position:0% +Enterprise is going to look very + + + align:start position:0% +Enterprise is going to look very +different in the future from what it + + align:start position:0% +different in the future from what it + + + align:start position:0% +different in the future from what it +looks like today we're seeing the + + align:start position:0% +looks like today we're seeing the + + + align:start position:0% +looks like today we're seeing the +fragmentation and globalization of + + align:start position:0% +fragmentation and globalization of + + + align:start position:0% +fragmentation and globalization of +production systems in Global Supply + + align:start position:0% +production systems in Global Supply + + + align:start position:0% +production systems in Global Supply +chains we need to understand what the + + align:start position:0% +chains we need to understand what the + + + align:start position:0% +chains we need to understand what the +full implications are of this new + + align:start position:0% +full implications are of this new + + + align:start position:0% +full implications are of this new +organization and Global division of + + align:start position:0% +organization and Global division of + + + align:start position:0% +organization and Global division of +labor and the fourth point and this is + + align:start position:0% +labor and the fourth point and this is + + + align:start position:0% +labor and the fourth point and this is +the culminating point of the of the + + align:start position:0% +the culminating point of the of the + + + align:start position:0% +the culminating point of the of the +whole thing we have to say well what are + + align:start position:0% +whole thing we have to say well what are + + + align:start position:0% +whole thing we have to say well what are +the consequences of these changes for + + align:start position:0% +the consequences of these changes for + + + align:start position:0% +the consequences of these changes for +the ilo's Mandate uh for social justice + + align:start position:0% +the ilo's Mandate uh for social justice + + + align:start position:0% +the ilo's Mandate uh for social justice +how can we shape manage all of these + + align:start position:0% +how can we shape manage all of these + + + align:start position:0% +how can we shape manage all of these +changes so that we keep the world moving + + align:start position:0% +changes so that we keep the world moving + + + align:start position:0% +changes so that we keep the world moving +in this direction of social justice so + + align:start position:0% +in this direction of social justice so + + + align:start position:0% +in this direction of social justice so +let me end by encouraging everyone to + + align:start position:0% +let me end by encouraging everyone to + + + align:start position:0% +let me end by encouraging everyone to +join us in using the ideas and the + + align:start position:0% +join us in using the ideas and the + + + align:start position:0% +join us in using the ideas and the +information presented in this course to + + align:start position:0% +information presented in this course to + + + align:start position:0% +information presented in this course to +improve the future of work for people + + align:start position:0% +improve the future of work for people + + + align:start position:0% +improve the future of work for people +all around the world \ No newline at end of file diff --git a/UGiED1HPB08.txt b/UGiED1HPB08.txt new file mode 100644 index 0000000000000000000000000000000000000000..43f0daf047bf8dad950cbdb7f2c2ad93fdd4a63d --- /dev/null +++ b/UGiED1HPB08.txt @@ -0,0 +1,5907 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +view additional materials from hundreds + + align:start position:0% +view additional materials from hundreds + + + align:start position:0% +view additional materials from hundreds +of MIT courses visit mitop courseware at + + align:start position:0% +of MIT courses visit mitop courseware at + + + align:start position:0% +of MIT courses visit mitop courseware at +ocw.mit.edu + + align:start position:0% + + + + align:start position:0% + +hi today we tackle another facet of + + align:start position:0% +hi today we tackle another facet of + + + align:start position:0% +hi today we tackle another facet of +applications of complex numbers in our + + align:start position:0% +applications of complex numbers in our + + + align:start position:0% +applications of complex numbers in our +survey of our complex variable mini + + align:start position:0% +survey of our complex variable mini + + + align:start position:0% +survey of our complex variable mini +course and in particular what we're + + align:start position:0% +course and in particular what we're + + + align:start position:0% +course and in particular what we're +going to study today is the role of + + align:start position:0% +going to study today is the role of + + + align:start position:0% +going to study today is the role of +infinite series and sequences in complex + + align:start position:0% +infinite series and sequences in complex + + + align:start position:0% +infinite series and sequences in complex +numbers and I call today's lesson + + align:start position:0% +numbers and I call today's lesson + + + align:start position:0% +numbers and I call today's lesson +therefore sequences and series now among + + align:start position:0% +therefore sequences and series now among + + + align:start position:0% +therefore sequences and series now among +other things let's take a look at a p a + + align:start position:0% +other things let's take a look at a p a + + + align:start position:0% +other things let's take a look at a p a +purely pedagogical problem for example + + align:start position:0% +purely pedagogical problem for example + + + align:start position:0% +purely pedagogical problem for example +at this stage of the game notice that I + + align:start position:0% +at this stage of the game notice that I + + + align:start position:0% +at this stage of the game notice that I +can't even talk meaningfully about what + + align:start position:0% +can't even talk meaningfully about what + + + align:start position:0% +can't even talk meaningfully about what +I mean by e to the Z nor by what I mean + + align:start position:0% +I mean by e to the Z nor by what I mean + + + align:start position:0% +I mean by e to the Z nor by what I mean +by sinine Z I can not visualize Z as an + + align:start position:0% +by sinine Z I can not visualize Z as an + + + align:start position:0% +by sinine Z I can not visualize Z as an +angle because it may be imaginary I + + align:start position:0% +angle because it may be imaginary I + + + align:start position:0% +angle because it may be imaginary I +can't visualize it uh as a length in the + + align:start position:0% +can't visualize it uh as a length in the + + + align:start position:0% +can't visualize it uh as a length in the +traditional sense uh that we viewed + + align:start position:0% +traditional sense uh that we viewed + + + align:start position:0% +traditional sense uh that we viewed +functions from real variables into uh + + align:start position:0% +functions from real variables into uh + + + align:start position:0% +functions from real variables into uh +real + + align:start position:0% +real + + + align:start position:0% +real +variables and the question that comes up + + align:start position:0% +variables and the question that comes up + + + align:start position:0% +variables and the question that comes up +is how could I Define e to the Z and sin + + align:start position:0% +is how could I Define e to the Z and sin + + + align:start position:0% +is how could I Define e to the Z and sin +Z in fact the cynic might say why would + + align:start position:0% +Z in fact the cynic might say why would + + + align:start position:0% +Z in fact the cynic might say why would +you want to Define e to the Z and sin Z + + align:start position:0% +you want to Define e to the Z and sin Z + + + align:start position:0% +you want to Define e to the Z and sin Z +Now one very cynical answer to the synic + + align:start position:0% +Now one very cynical answer to the synic + + + align:start position:0% +Now one very cynical answer to the synic +would simply be that one of the most + + align:start position:0% +would simply be that one of the most + + + align:start position:0% +would simply be that one of the most +practical reasons for knowing how to + + align:start position:0% +practical reasons for knowing how to + + + align:start position:0% +practical reasons for knowing how to +define e to the Z and sin Z is that they + + align:start position:0% +define e to the Z and sin Z is that they + + + align:start position:0% +define e to the Z and sin Z is that they +will be on the quiz at the end of this + + align:start position:0% +will be on the quiz at the end of this + + + align:start position:0% +will be on the quiz at the end of this +particular block but that's hardly a + + align:start position:0% +particular block but that's hardly a + + + align:start position:0% +particular block but that's hardly a +fair motivation I will go into this in + + align:start position:0% +fair motivation I will go into this in + + + align:start position:0% +fair motivation I will go into this in +more detail later in the lecture let me + + align:start position:0% +more detail later in the lecture let me + + + align:start position:0% +more detail later in the lecture let me +simply point out that every time we have + + align:start position:0% +simply point out that every time we have + + + align:start position:0% +simply point out that every time we have +an analytic function its real and + + align:start position:0% +an analytic function its real and + + + align:start position:0% +an analytic function its real and +imaginary Parts Define a conformal + + align:start position:0% +imaginary Parts Define a conformal + + + align:start position:0% +imaginary Parts Define a conformal +mapping and consequently every time we + + align:start position:0% +mapping and consequently every time we + + + align:start position:0% +mapping and consequently every time we +can meaningfully invent an analytic + + align:start position:0% +can meaningfully invent an analytic + + + align:start position:0% +can meaningfully invent an analytic +function we have automatically invented + + align:start position:0% +function we have automatically invented + + + align:start position:0% +function we have automatically invented +a new conformal mapping as I say we'll + + align:start position:0% +a new conformal mapping as I say we'll + + + align:start position:0% +a new conformal mapping as I say we'll +go into that in more detail as we go + + align:start position:0% +go into that in more detail as we go + + + align:start position:0% +go into that in more detail as we go +along but the question that now comes up + + align:start position:0% +along but the question that now comes up + + + align:start position:0% +along but the question that now comes up +is how can I define e to the Z how can I + + align:start position:0% +is how can I define e to the Z how can I + + + align:start position:0% +is how can I define e to the Z how can I +define s z Kos Z all of these things and + + align:start position:0% +define s z Kos Z all of these things and + + + align:start position:0% +define s z Kos Z all of these things and +one of the best ways of beginning is + + align:start position:0% +one of the best ways of beginning is + + + align:start position:0% +one of the best ways of beginning is +again again to emphasize something that + + align:start position:0% +again again to emphasize something that + + + align:start position:0% +again again to emphasize something that +we said in one of our earlier lectures + + align:start position:0% +we said in one of our earlier lectures + + + align:start position:0% +we said in one of our earlier lectures +on complex numbers that whatever + + align:start position:0% +on complex numbers that whatever + + + align:start position:0% +on complex numbers that whatever +definitions we invent we want to make + + align:start position:0% +definitions we invent we want to make + + + align:start position:0% +definitions we invent we want to make +sure that the new definition does not + + align:start position:0% +sure that the new definition does not + + + align:start position:0% +sure that the new definition does not +contradict the old one in other words + + align:start position:0% +contradict the old one in other words + + + align:start position:0% +contradict the old one in other words +whatever definition I give of e to the Z + + align:start position:0% +whatever definition I give of e to the Z + + + align:start position:0% +whatever definition I give of e to the Z +I want to make sure that if Z happens to + + align:start position:0% +I want to make sure that if Z happens to + + + align:start position:0% +I want to make sure that if Z happens to +be real if I replace Z by X that e to + + align:start position:0% +be real if I replace Z by X that e to + + + align:start position:0% +be real if I replace Z by X that e to +the X has the same meaning whether I + + align:start position:0% +the X has the same meaning whether I + + + align:start position:0% +the X has the same meaning whether I +view X as a real number or whether I + + align:start position:0% +view X as a real number or whether I + + + align:start position:0% +view X as a real number or whether I +view it as a complex number now now one + + align:start position:0% +view it as a complex number now now one + + + align:start position:0% +view it as a complex number now now one +of the standard ways of doing something + + align:start position:0% +of the standard ways of doing something + + + align:start position:0% +of the standard ways of doing something +like this is the following we in part + + align:start position:0% +like this is the following we in part + + + align:start position:0% +like this is the following we in part +one of our course had shown that the + + align:start position:0% +one of our course had shown that the + + + align:start position:0% +one of our course had shown that the +power series representation for e to the + + align:start position:0% +power series representation for e to the + + + align:start position:0% +power series representation for e to the +X was given by this infinite Series + + align:start position:0% +X was given by this infinite Series + + + align:start position:0% +X was given by this infinite Series +where this infinite series converged to + + align:start position:0% +where this infinite series converged to + + + align:start position:0% +where this infinite series converged to +e to the X for all real values of X now + + align:start position:0% +e to the X for all real values of X now + + + align:start position:0% +e to the X for all real values of X now +what we can therefore say is look at if + + align:start position:0% +what we can therefore say is look at if + + + align:start position:0% +what we can therefore say is look at if +I just verbatim every place I see an X + + align:start position:0% +I just verbatim every place I see an X + + + align:start position:0% +I just verbatim every place I see an X +replace that by a z and and now make up + + align:start position:0% +replace that by a z and and now make up + + + align:start position:0% +replace that by a z and and now make up +the definition that e to the Z will be + + align:start position:0% +the definition that e to the Z will be + + + align:start position:0% +the definition that e to the Z will be +summation n goes from 0 to Infinity Z to + + align:start position:0% +summation n goes from 0 to Infinity Z to + + + align:start position:0% +summation n goes from 0 to Infinity Z to +the N / n factorial then no matter what + + align:start position:0% +the N / n factorial then no matter what + + + align:start position:0% +the N / n factorial then no matter what +else happens I'm sure that my definition + + align:start position:0% +else happens I'm sure that my definition + + + align:start position:0% +else happens I'm sure that my definition +of e to the Z must agree with my + + align:start position:0% +of e to the Z must agree with my + + + align:start position:0% +of e to the Z must agree with my +definition of e to the X whenever Z and + + align:start position:0% +definition of e to the X whenever Z and + + + align:start position:0% +definition of e to the X whenever Z and +X are equal in other words whenever Z + + align:start position:0% +X are equal in other words whenever Z + + + align:start position:0% +X are equal in other words whenever Z +happens to denote a real number why is + + align:start position:0% +happens to denote a real number why is + + + align:start position:0% +happens to denote a real number why is +that the case because I got the new + + align:start position:0% +that the case because I got the new + + + align:start position:0% +that the case because I got the new +definition by lifting it from the old + + align:start position:0% +definition by lifting it from the old + + + align:start position:0% +definition by lifting it from the old +just replacing X by a z the question + + align:start position:0% +just replacing X by a z the question + + + align:start position:0% +just replacing X by a z the question +that comes up of course is what do you + + align:start position:0% +that comes up of course is what do you + + + align:start position:0% +that comes up of course is what do you +mean by this expression what do you mean + + align:start position:0% +mean by this expression what do you mean + + + align:start position:0% +mean by this expression what do you mean +by a series when you're dealing with + + align:start position:0% +by a series when you're dealing with + + + align:start position:0% +by a series when you're dealing with +complex numbers in particular what it + + align:start position:0% +complex numbers in particular what it + + + align:start position:0% +complex numbers in particular what it +means is is that given a sequence of + + align:start position:0% +means is is that given a sequence of + + + align:start position:0% +means is is that given a sequence of +complex numbers I must Define what I + + align:start position:0% +complex numbers I must Define what I + + + align:start position:0% +complex numbers I must Define what I +mean by a limit and then go through this + + align:start position:0% +mean by a limit and then go through this + + + align:start position:0% +mean by a limit and then go through this +idea of defining a series to be a + + align:start position:0% +idea of defining a series to be a + + + align:start position:0% +idea of defining a series to be a +sequence of partial sums and going + + align:start position:0% +sequence of partial sums and going + + + align:start position:0% +sequence of partial sums and going +through the same bit structurally that I + + align:start position:0% +through the same bit structurally that I + + + align:start position:0% +through the same bit structurally that I +went through in the real case + + align:start position:0% +went through in the real case + + + align:start position:0% +went through in the real case +now let's do something that I think is + + align:start position:0% +now let's do something that I think is + + + align:start position:0% +now let's do something that I think is +very interesting over here let's just + + align:start position:0% +very interesting over here let's just + + + align:start position:0% +very interesting over here let's just +write down what the diff the definition + + align:start position:0% +write down what the diff the definition + + + align:start position:0% +write down what the diff the definition +was for a limit of a sequence a subn to + + align:start position:0% +was for a limit of a sequence a subn to + + + align:start position:0% +was for a limit of a sequence a subn to +equal L as n went to Infinity what was + + align:start position:0% +equal L as n went to Infinity what was + + + align:start position:0% +equal L as n went to Infinity what was +that definition in the real case limit + + align:start position:0% +that definition in the real case limit + + + align:start position:0% +that definition in the real case limit +as n approaches Infinity a subn equals l + + align:start position:0% +as n approaches Infinity a subn equals l + + + align:start position:0% +as n approaches Infinity a subn equals l +means given any Epsilon greater than + + align:start position:0% +means given any Epsilon greater than + + + align:start position:0% +means given any Epsilon greater than +zero there exists a capital N such that + + align:start position:0% +zero there exists a capital N such that + + + align:start position:0% +zero there exists a capital N such that +whenever little n exceeds capital N the + + align:start position:0% +whenever little n exceeds capital N the + + + align:start position:0% +whenever little n exceeds capital N the +absolute value of a subn minus L is less + + align:start position:0% +absolute value of a subn minus L is less + + + align:start position:0% +absolute value of a subn minus L is less +than Epsilon I hope this is very + + align:start position:0% +than Epsilon I hope this is very + + + align:start position:0% +than Epsilon I hope this is very +familiar to you if not feel free to + + align:start position:0% +familiar to you if not feel free to + + + align:start position:0% +familiar to you if not feel free to +review it but here is the interesting + + align:start position:0% +review it but here is the interesting + + + align:start position:0% +review it but here is the interesting +point no place in here do I mention that + + align:start position:0% +point no place in here do I mention that + + + align:start position:0% +point no place in here do I mention that +as sa Ben and L have to be real numbers + + align:start position:0% +as sa Ben and L have to be real numbers + + + align:start position:0% +as sa Ben and L have to be real numbers +in other words when I made up this + + align:start position:0% +in other words when I made up this + + + align:start position:0% +in other words when I made up this +definition I assumed that they were but + + align:start position:0% +definition I assumed that they were but + + + align:start position:0% +definition I assumed that they were but +notice that no place in here in this + + align:start position:0% +notice that no place in here in this + + + align:start position:0% +notice that no place in here in this +definition do I say that Asen and L are + + align:start position:0% +definition do I say that Asen and L are + + + align:start position:0% +definition do I say that Asen and L are +real in fact where are the only places + + align:start position:0% +real in fact where are the only places + + + align:start position:0% +real in fact where are the only places +that I use realness that since Epsilon + + align:start position:0% +that I use realness that since Epsilon + + + align:start position:0% +that I use realness that since Epsilon +is real I would like to believe that no + + align:start position:0% +is real I would like to believe that no + + + align:start position:0% +is real I would like to believe that no +matter what Ace and LR that the + + align:start position:0% +matter what Ace and LR that the + + + align:start position:0% +matter what Ace and LR that the +magnitude the absolute value of a subn + + align:start position:0% +magnitude the absolute value of a subn + + + align:start position:0% +magnitude the absolute value of a subn +minus L must be less than Epsilon means + + align:start position:0% +minus L must be less than Epsilon means + + + align:start position:0% +minus L must be less than Epsilon means +that the magnitude of a subn minus L + + align:start position:0% +that the magnitude of a subn minus L + + + align:start position:0% +that the magnitude of a subn minus L +must be a real number among other things + + align:start position:0% +must be a real number among other things + + + align:start position:0% +must be a real number among other things +in fact preferably a positive real + + align:start position:0% +in fact preferably a positive real + + + align:start position:0% +in fact preferably a positive real +number notice that the magnitude of a + + align:start position:0% +number notice that the magnitude of a + + + align:start position:0% +number notice that the magnitude of a +complex number is still a non- negative + + align:start position:0% +complex number is still a non- negative + + + align:start position:0% +complex number is still a non- negative +real consequently even if a subn and L + + align:start position:0% +real consequently even if a subn and L + + + align:start position:0% +real consequently even if a subn and L +are complex this definition still holds + + align:start position:0% +are complex this definition still holds + + + align:start position:0% +are complex this definition still holds +and in fact the pictorial interpretation + + align:start position:0% +and in fact the pictorial interpretation + + + align:start position:0% +and in fact the pictorial interpretation +of the definition holds precisely the + + align:start position:0% +of the definition holds precisely the + + + align:start position:0% +of the definition holds precisely the +same as the did in the real case except + + align:start position:0% +same as the did in the real case except + + + align:start position:0% +same as the did in the real case except +that an Epsilon neighborhood of L is an + + align:start position:0% +that an Epsilon neighborhood of L is an + + + align:start position:0% +that an Epsilon neighborhood of L is an +interval in the real case and it's a + + align:start position:0% +interval in the real case and it's a + + + align:start position:0% +interval in the real case and it's a +circle a disc I shouldn't say a circle + + align:start position:0% +circle a disc I shouldn't say a circle + + + align:start position:0% +circle a disc I shouldn't say a circle +remember the circle is the circum the + + align:start position:0% +remember the circle is the circum the + + + align:start position:0% +remember the circle is the circum the +thing we call the circumference the dis + + align:start position:0% +thing we call the circumference the dis + + + align:start position:0% +thing we call the circumference the dis +is the inside of the circle the uh the + + align:start position:0% +is the inside of the circle the uh the + + + align:start position:0% +is the inside of the circle the uh the +neighborhood is a dis in the complex + + align:start position:0% +neighborhood is a dis in the complex + + + align:start position:0% +neighborhood is a dis in the complex +case namely notice that to say that the + + align:start position:0% +case namely notice that to say that the + + + align:start position:0% +case namely notice that to say that the +absolute value of a subn minus L is less + + align:start position:0% +absolute value of a subn minus L is less + + + align:start position:0% +absolute value of a subn minus L is less +than Epsilon still means that a subn is + + align:start position:0% +than Epsilon still means that a subn is + + + align:start position:0% +than Epsilon still means that a subn is +with an Epsilon of L the difference is + + align:start position:0% +with an Epsilon of L the difference is + + + align:start position:0% +with an Epsilon of L the difference is +that the domain of L is now the XY plane + + align:start position:0% +that the domain of L is now the XY plane + + + align:start position:0% +that the domain of L is now the XY plane +the Aon diagram so to be with an Epsilon + + align:start position:0% +the Aon diagram so to be with an Epsilon + + + align:start position:0% +the Aon diagram so to be with an Epsilon +of l i now take a circle centered at L + + align:start position:0% +of l i now take a circle centered at L + + + align:start position:0% +of l i now take a circle centered at L +with radius Epsilon and draw that Circle + + align:start position:0% +with radius Epsilon and draw that Circle + + + align:start position:0% +with radius Epsilon and draw that Circle +and what I'm saying is that if the limit + + align:start position:0% +and what I'm saying is that if the limit + + + align:start position:0% +and what I'm saying is that if the limit +of the sequence is L after a certain + + align:start position:0% +of the sequence is L after a certain + + + align:start position:0% +of the sequence is L after a certain +number of terms all the remaining terms + + align:start position:0% +number of terms all the remaining terms + + + align:start position:0% +number of terms all the remaining terms +are inside this circle in other words + + align:start position:0% +are inside this circle in other words + + + align:start position:0% +are inside this circle in other words +just as in the real case in the complex + + align:start position:0% +just as in the real case in the complex + + + align:start position:0% +just as in the real case in the complex +case the limit replaces an infinite + + align:start position:0% +case the limit replaces an infinite + + + align:start position:0% +case the limit replaces an infinite +number of points DOT uh numbers you see + + align:start position:0% +number of points DOT uh numbers you see + + + align:start position:0% +number of points DOT uh numbers you see +an infinite number of points by a finite + + align:start position:0% +an infinite number of points by a finite + + + align:start position:0% +an infinite number of points by a finite +number plus one dot in other words + + align:start position:0% +number plus one dot in other words + + + align:start position:0% +number plus one dot in other words +there's a bunch of numbers that may lie + + align:start position:0% +there's a bunch of numbers that may lie + + + align:start position:0% +there's a bunch of numbers that may lie +outside the circle but after a point + + align:start position:0% +outside the circle but after a point + + + align:start position:0% +outside the circle but after a point +after a certain term all of the + + align:start position:0% +after a certain term all of the + + + align:start position:0% +after a certain term all of the +remaining terms lie inside this + + align:start position:0% +remaining terms lie inside this + + + align:start position:0% +remaining terms lie inside this +particular dis and structurally you see + + align:start position:0% +particular dis and structurally you see + + + align:start position:0% +particular dis and structurally you see +that's exactly the same thing that + + align:start position:0% +that's exactly the same thing that + + + align:start position:0% +that's exactly the same thing that +happen in the real case consequently + + align:start position:0% +happen in the real case consequently + + + align:start position:0% +happen in the real case consequently +since the structural definition is the + + align:start position:0% +since the structural definition is the + + + align:start position:0% +since the structural definition is the +same since the geometric interpretation + + align:start position:0% +same since the geometric interpretation + + + align:start position:0% +same since the geometric interpretation +is the same except that diss have + + align:start position:0% +is the same except that diss have + + + align:start position:0% +is the same except that diss have +replaced + + align:start position:0% +replaced + + + align:start position:0% +replaced +intervals I would expect that all the + + align:start position:0% +intervals I would expect that all the + + + align:start position:0% +intervals I would expect that all the +limit theorems held just as in the real + + align:start position:0% +limit theorems held just as in the real + + + align:start position:0% +limit theorems held just as in the real +case and indeed they do and we'll talk + + align:start position:0% +case and indeed they do and we'll talk + + + align:start position:0% +case and indeed they do and we'll talk +about those in the exercises in a + + align:start position:0% +about those in the exercises in a + + + align:start position:0% +about those in the exercises in a +similar way though that we went from + + align:start position:0% +similar way though that we went from + + + align:start position:0% +similar way though that we went from +sequences to Series in the real case we + + align:start position:0% +sequences to Series in the real case we + + + align:start position:0% +sequences to Series in the real case we +can now do the same thing in the complex + + align:start position:0% +can now do the same thing in the complex + + + align:start position:0% +can now do the same thing in the complex +case namely suppose C1 C2 C3 ETC + + align:start position:0% +case namely suppose C1 C2 C3 ETC + + + align:start position:0% +case namely suppose C1 C2 C3 ETC +represent a sequence of complex numbers + + align:start position:0% +represent a sequence of complex numbers + + + align:start position:0% +represent a sequence of complex numbers +by the infinite sum n goes from 1 to + + align:start position:0% +by the infinite sum n goes from 1 to + + + align:start position:0% +by the infinite sum n goes from 1 to +Infinity C subn I simply mean the limit + + align:start position:0% +Infinity C subn I simply mean the limit + + + align:start position:0% +Infinity C subn I simply mean the limit +as n goes to Infinity C1 plus Etc CN + + align:start position:0% +as n goes to Infinity C1 plus Etc CN + + + align:start position:0% +as n goes to Infinity C1 plus Etc CN +noticing that this is what one number it + + align:start position:0% +noticing that this is what one number it + + + align:start position:0% +noticing that this is what one number it +depends on n and it's what you call the + + align:start position:0% +depends on n and it's what you call the + + + align:start position:0% +depends on n and it's what you call the +nth partial sum of the series that we've + + align:start position:0% +nth partial sum of the series that we've + + + align:start position:0% +nth partial sum of the series that we've +added up C1 through CN the next term + + align:start position:0% +added up C1 through CN the next term + + + align:start position:0% +added up C1 through CN the next term +would be obtained by adding on CN C subn + + align:start position:0% +would be obtained by adding on CN C subn + + + align:start position:0% +would be obtained by adding on CN C subn +plus 1 Etc but notice again the similar + + align:start position:0% +plus 1 Etc but notice again the similar + + + align:start position:0% +plus 1 Etc but notice again the similar +structure and consequently the usual + + align:start position:0% +structure and consequently the usual + + + align:start position:0% +structure and consequently the usual +theorems for series that apply to the + + align:start position:0% +theorems for series that apply to the + + + align:start position:0% +theorems for series that apply to the +real variable case apply to the complex + + align:start position:0% +real variable case apply to the complex + + + align:start position:0% +real variable case apply to the complex +variable case again what's the only + + align:start position:0% +variable case again what's the only + + + align:start position:0% +variable case again what's the only +difference the only difference will be + + align:start position:0% +difference the only difference will be + + + align:start position:0% +difference the only difference will be +that intervals of convergence will be + + align:start position:0% +that intervals of convergence will be + + + align:start position:0% +that intervals of convergence will be +replaced by diss or Circles of + + align:start position:0% +replaced by diss or Circles of + + + align:start position:0% +replaced by diss or Circles of +convergence in particular if we let s + + align:start position:0% +convergence in particular if we let s + + + align:start position:0% +convergence in particular if we let s +denote the set of all complex numberers + + align:start position:0% +denote the set of all complex numberers + + + align:start position:0% +denote the set of all complex numberers +Z for which the power series summation a + + align:start position:0% +Z for which the power series summation a + + + align:start position:0% +Z for which the power series summation a +n z to the N converges then just as in + + align:start position:0% +n z to the N converges then just as in + + + align:start position:0% +n z to the N converges then just as in +the real case one of three things must + + align:start position:0% +the real case one of three things must + + + align:start position:0% +the real case one of three things must +happen namely either s consists solely + + align:start position:0% +happen namely either s consists solely + + + align:start position:0% +happen namely either s consists solely +of zero see obviously if I replace Z by + + align:start position:0% +of zero see obviously if I replace Z by + + + align:start position:0% +of zero see obviously if I replace Z by +Zer this thing converges it's + + align:start position:0% +Zer this thing converges it's + + + align:start position:0% +Zer this thing converges it's +identically zero in fact or it may be + + align:start position:0% +identically zero in fact or it may be + + + align:start position:0% +identically zero in fact or it may be +such that these terms go to zero so + + align:start position:0% +such that these terms go to zero so + + + align:start position:0% +such that these terms go to zero so +rapidly that this will converge for all + + align:start position:0% +rapidly that this will converge for all + + + align:start position:0% +rapidly that this will converge for all +complex numb C in other words that the + + align:start position:0% +complex numb C in other words that the + + + align:start position:0% +complex numb C in other words that the +in that the set s can be all complex + + align:start position:0% +in that the set s can be all complex + + + align:start position:0% +in that the set s can be all complex +numbers usually you'll get something in + + align:start position:0% +numbers usually you'll get something in + + + align:start position:0% +numbers usually you'll get something in +between these two extremes and that's + + align:start position:0% +between these two extremes and that's + + + align:start position:0% +between these two extremes and that's +the case like just in the real case + + align:start position:0% +the case like just in the real case + + + align:start position:0% +the case like just in the real case +there exists a number capital r than + + align:start position:0% +there exists a number capital r than + + + align:start position:0% +there exists a number capital r than +zero such that the set s consists of all + + align:start position:0% +zero such that the set s consists of all + + + align:start position:0% +zero such that the set s consists of all +of those Z's such that the absolute + + align:start position:0% +of those Z's such that the absolute + + + align:start position:0% +of those Z's such that the absolute +value of Z is less than R and by the way + + align:start position:0% +value of Z is less than R and by the way + + + align:start position:0% +value of Z is less than R and by the way +what does this mean geometrically the + + align:start position:0% +what does this mean geometrically the + + + align:start position:0% +what does this mean geometrically the +absolute value of Z is the magnitude of + + align:start position:0% +absolute value of Z is the magnitude of + + + align:start position:0% +absolute value of Z is the magnitude of +Z that's the distance of Z from the + + align:start position:0% +Z that's the distance of Z from the + + + align:start position:0% +Z that's the distance of Z from the +origin this says that Z is within + + align:start position:0% +origin this says that Z is within + + + align:start position:0% +origin this says that Z is within +capital r of the origin that means + + align:start position:0% +capital r of the origin that means + + + align:start position:0% +capital r of the origin that means +you're inside the circle centered at the + + align:start position:0% +you're inside the circle centered at the + + + align:start position:0% +you're inside the circle centered at the +origin with radius r at any rate going + + align:start position:0% +origin with radius r at any rate going + + + align:start position:0% +origin with radius r at any rate going +on the convergence is both absolute and + + align:start position:0% +on the convergence is both absolute and + + + align:start position:0% +on the convergence is both absolute and +uniform in any interior disc in other + + align:start position:0% +uniform in any interior disc in other + + + align:start position:0% +uniform in any interior disc in other +words inside the disc absolute value of + + align:start position:0% +words inside the disc absolute value of + + + align:start position:0% +words inside the disc absolute value of +Z is less than or equal to little r + + align:start position:0% +Z is less than or equal to little r + + + align:start position:0% +Z is less than or equal to little r +where little r is less than capital r + + align:start position:0% +where little r is less than capital r + + + align:start position:0% +where little r is less than capital r +again in terms of a picture what we're + + align:start position:0% +again in terms of a picture what we're + + + align:start position:0% +again in terms of a picture what we're +saying is if the first two conditions + + align:start position:0% +saying is if the first two conditions + + + align:start position:0% +saying is if the first two conditions +don't hold given a power series at the + + align:start position:0% +don't hold given a power series at the + + + align:start position:0% +don't hold given a power series at the +origin I draw a circle I don't draw a + + align:start position:0% +origin I draw a circle I don't draw a + + + align:start position:0% +origin I draw a circle I don't draw a +circle what I'm saying is there exists a + + align:start position:0% +circle what I'm saying is there exists a + + + align:start position:0% +circle what I'm saying is there exists a +circle such that the power series will + + align:start position:0% +circle such that the power series will + + + align:start position:0% +circle such that the power series will +converge every place inside here it will + + align:start position:0% +converge every place inside here it will + + + align:start position:0% +converge every place inside here it will +diverge every place outside here and + + align:start position:0% +diverge every place outside here and + + + align:start position:0% +diverge every place outside here and +what happens on the boundary must be + + align:start position:0% +what happens on the boundary must be + + + align:start position:0% +what happens on the boundary must be +investigated separately again just as in + + align:start position:0% +investigated separately again just as in + + + align:start position:0% +investigated separately again just as in +the real case okay that's what the key + + align:start position:0% +the real case okay that's what the key + + + align:start position:0% +the real case okay that's what the key +theorem is and again you'll have time to + + align:start position:0% +theorem is and again you'll have time to + + + align:start position:0% +theorem is and again you'll have time to +reread this and to digest it in your + + align:start position:0% +reread this and to digest it in your + + + align:start position:0% +reread this and to digest it in your +leisure before you try the + + align:start position:0% +leisure before you try the + + + align:start position:0% +leisure before you try the +exercises now once we've defined what we + + align:start position:0% +exercises now once we've defined what we + + + align:start position:0% +exercises now once we've defined what we +mean by a power series and notice by the + + align:start position:0% +mean by a power series and notice by the + + + align:start position:0% +mean by a power series and notice by the +way that absolute convergence goes + + align:start position:0% +way that absolute convergence goes + + + align:start position:0% +way that absolute convergence goes +through word for word in the complex + + align:start position:0% +through word for word in the complex + + + align:start position:0% +through word for word in the complex +valued case because after all in terms + + align:start position:0% +valued case because after all in terms + + + align:start position:0% +valued case because after all in terms +of absolute convergence we look at + + align:start position:0% +of absolute convergence we look at + + + align:start position:0% +of absolute convergence we look at +absolute values and absolute values are + + align:start position:0% +absolute values and absolute values are + + + align:start position:0% +absolute values and absolute values are +non- negative reals regardless of + + align:start position:0% +non- negative reals regardless of + + + align:start position:0% +non- negative reals regardless of +whether the thing that we're looking at + + align:start position:0% +whether the thing that we're looking at + + + align:start position:0% +whether the thing that we're looking at +happen to be complex numbers or real + + align:start position:0% +happen to be complex numbers or real + + + align:start position:0% +happen to be complex numbers or real +numbers to begin with magnitudes are + + align:start position:0% +numbers to begin with magnitudes are + + + align:start position:0% +numbers to begin with magnitudes are +non- negative at any rate one can then + + align:start position:0% +non- negative at any rate one can then + + + align:start position:0% +non- negative at any rate one can then +show in precisely the same way that we + + align:start position:0% +show in precisely the same way that we + + + align:start position:0% +show in precisely the same way that we +did it in the real variable case that + + align:start position:0% +did it in the real variable case that + + + align:start position:0% +did it in the real variable case that +this particular power series see forget + + align:start position:0% +this particular power series see forget + + + align:start position:0% +this particular power series see forget +about this being e to the Z right now I + + align:start position:0% +about this being e to the Z right now I + + + align:start position:0% +about this being e to the Z right now I +make up this power series I use the + + align:start position:0% +make up this power series I use the + + + align:start position:0% +make up this power series I use the +ratio test and I can show by the ratio + + align:start position:0% +ratio test and I can show by the ratio + + + align:start position:0% +ratio test and I can show by the ratio +test that this series converges + + align:start position:0% +test that this series converges + + + align:start position:0% +test that this series converges +uniformly and absolutely for all real + + align:start position:0% +uniformly and absolutely for all real + + + align:start position:0% +uniformly and absolutely for all real +values of Z which I I'm sorry for all + + align:start position:0% +values of Z which I I'm sorry for all + + + align:start position:0% +values of Z which I I'm sorry for all +finite values of Z I don't mean real + + align:start position:0% +finite values of Z I don't mean real + + + align:start position:0% +finite values of Z I don't mean real +values I mean finite values Z does not + + align:start position:0% +values I mean finite values Z does not + + + align:start position:0% +values I mean finite values Z does not +have to be real okay now what I say is + + align:start position:0% +have to be real okay now what I say is + + + align:start position:0% +have to be real okay now what I say is +because this is uniformly convergent + + align:start position:0% +because this is uniformly convergent + + + align:start position:0% +because this is uniformly convergent +this power series behaves like a + + align:start position:0% +this power series behaves like a + + + align:start position:0% +this power series behaves like a +polinomial I can differentiate a term by + + align:start position:0% +polinomial I can differentiate a term by + + + align:start position:0% +polinomial I can differentiate a term by +term I can integrate a term by term Etc + + align:start position:0% +term I can integrate a term by term Etc + + + align:start position:0% +term I can integrate a term by term Etc +ET etc etc I'll now give this a name and + + align:start position:0% +ET etc etc I'll now give this a name and + + + align:start position:0% +ET etc etc I'll now give this a name and +being very very judicious what name do I + + align:start position:0% +being very very judicious what name do I + + + align:start position:0% +being very very judicious what name do I +pick I pick e to the Z because that's + + align:start position:0% +pick I pick e to the Z because that's + + + align:start position:0% +pick I pick e to the Z because that's +what motivated my inventing this + + align:start position:0% +what motivated my inventing this + + + align:start position:0% +what motivated my inventing this +function this series in the first place + + align:start position:0% +function this series in the first place + + + align:start position:0% +function this series in the first place +and what am I now sure of I'm sure of + + align:start position:0% +and what am I now sure of I'm sure of + + + align:start position:0% +and what am I now sure of I'm sure of +the fact that if I replace Z by X in + + align:start position:0% +the fact that if I replace Z by X in + + + align:start position:0% +the fact that if I replace Z by X in +other words if Z is real that this must + + align:start position:0% +other words if Z is real that this must + + + align:start position:0% +other words if Z is real that this must +still be the same as what e to the X was + + align:start position:0% +still be the same as what e to the X was + + + align:start position:0% +still be the same as what e to the X was +before and what's the best proof of that + + align:start position:0% +before and what's the best proof of that + + + align:start position:0% +before and what's the best proof of that +replace Z by x what you get is summation + + align:start position:0% +replace Z by x what you get is summation + + + align:start position:0% +replace Z by x what you get is summation +n goes from 0 To infinity x to the N / n + + align:start position:0% +n goes from 0 To infinity x to the N / n + + + align:start position:0% +n goes from 0 To infinity x to the N / n +factorial and we saw in part one of our + + align:start position:0% +factorial and we saw in part one of our + + + align:start position:0% +factorial and we saw in part one of our +course that that was precisely e to X + + align:start position:0% +course that that was precisely e to X + + + align:start position:0% +course that that was precisely e to X +well since exponentials May bother you a + + align:start position:0% +well since exponentials May bother you a + + + align:start position:0% +well since exponentials May bother you a +little bit more than SS and cosiness + + align:start position:0% +little bit more than SS and cosiness + + + align:start position:0% +little bit more than SS and cosiness +let's revisit the same problem in terms + + align:start position:0% +let's revisit the same problem in terms + + + align:start position:0% +let's revisit the same problem in terms +of s z what I do is is I Define sin Z to + + align:start position:0% +of s z what I do is is I Define sin Z to + + + align:start position:0% +of s z what I do is is I Define sin Z to +be this uniformly absolutely convergent + + align:start position:0% +be this uniformly absolutely convergent + + + align:start position:0% +be this uniformly absolutely convergent +power series see I use again using + + align:start position:0% +power series see I use again using + + + align:start position:0% +power series see I use again using +hindsight knowing that in the case of + + align:start position:0% +hindsight knowing that in the case of + + + align:start position:0% +hindsight knowing that in the case of +sinx this was the convergent power + + align:start position:0% +sinx this was the convergent power + + + align:start position:0% +sinx this was the convergent power +series I simply replace X by Z up + + align:start position:0% +series I simply replace X by Z up + + + align:start position:0% +series I simply replace X by Z up +here all right I replace X by z i now + + align:start position:0% +here all right I replace X by z i now + + + align:start position:0% +here all right I replace X by z i now +use the ratio test on this to show that + + align:start position:0% +use the ratio test on this to show that + + + align:start position:0% +use the ratio test on this to show that +this does converge for all finite Z in + + align:start position:0% +this does converge for all finite Z in + + + align:start position:0% +this does converge for all finite Z in +fact that's sort of redundant to do that + + align:start position:0% +fact that's sort of redundant to do that + + + align:start position:0% +fact that's sort of redundant to do that +I know Dar well that's going to happen + + align:start position:0% +I know Dar well that's going to happen + + + align:start position:0% +I know Dar well that's going to happen +because it happened here and + + align:start position:0% +because it happened here and + + + align:start position:0% +because it happened here and +structurally these are the same but I + + align:start position:0% +structurally these are the same but I + + + align:start position:0% +structurally these are the same but I +now then after showing that I say okay + + align:start position:0% +now then after showing that I say okay + + + align:start position:0% +now then after showing that I say okay +this converges for all Z let's give it a + + align:start position:0% +this converges for all Z let's give it a + + + align:start position:0% +this converges for all Z let's give it a +name I'll call it sin Z and what + + align:start position:0% +name I'll call it sin Z and what + + + align:start position:0% +name I'll call it sin Z and what +guarantee do I have that sin Z is the + + align:start position:0% +guarantee do I have that sin Z is the + + + align:start position:0% +guarantee do I have that sin Z is the +same as sin x whenever Z is real and + + align:start position:0% +same as sin x whenever Z is real and + + + align:start position:0% +same as sin x whenever Z is real and +again let me point out something notice + + align:start position:0% +again let me point out something notice + + + align:start position:0% +again let me point out something notice +in the real case we started knowing what + + align:start position:0% +in the real case we started knowing what + + + align:start position:0% +in the real case we started knowing what +sinx was but not knowing what its power + + align:start position:0% +sinx was but not knowing what its power + + + align:start position:0% +sinx was but not knowing what its power +series expansion was and we developed + + align:start position:0% +series expansion was and we developed + + + align:start position:0% +series expansion was and we developed +the power series expansion and by the + + align:start position:0% +the power series expansion and by the + + + align:start position:0% +the power series expansion and by the +way notice that when you want to compute + + align:start position:0% +way notice that when you want to compute + + + align:start position:0% +way notice that when you want to compute +sinx to any number of decimal places + + align:start position:0% +sinx to any number of decimal places + + + align:start position:0% +sinx to any number of decimal places +whether you doing it by hand or by the + + align:start position:0% +whether you doing it by hand or by the + + + align:start position:0% +whether you doing it by hand or by the +computer notice that it's the power + + align:start position:0% +computer notice that it's the power + + + align:start position:0% +computer notice that it's the power +series that you use you see and you + + align:start position:0% +series that you use you see and you + + + align:start position:0% +series that you use you see and you +you chop this off after a certain number + + align:start position:0% +you chop this off after a certain number + + + align:start position:0% +you chop this off after a certain number +of terms if you wish but one does use + + align:start position:0% +of terms if you wish but one does use + + + align:start position:0% +of terms if you wish but one does use +the power series idea what I am saying + + align:start position:0% +the power series idea what I am saying + + + align:start position:0% +the power series idea what I am saying +though is had I wish to from a purely + + align:start position:0% +though is had I wish to from a purely + + + align:start position:0% +though is had I wish to from a purely +pedagogical point of view I could have + + align:start position:0% +pedagogical point of view I could have + + + align:start position:0% +pedagogical point of view I could have +said look at let me now forget about + + align:start position:0% +said look at let me now forget about + + + align:start position:0% +said look at let me now forget about +this definition of sinx and Define sinx + + align:start position:0% +this definition of sinx and Define sinx + + + align:start position:0% +this definition of sinx and Define sinx +just by this particular power series + + align:start position:0% +just by this particular power series + + + align:start position:0% +just by this particular power series +that would have been artificial to do at + + align:start position:0% +that would have been artificial to do at + + + align:start position:0% +that would have been artificial to do at +that time what I'm saying now though is + + align:start position:0% +that time what I'm saying now though is + + + align:start position:0% +that time what I'm saying now though is +this start with sinx in the real case + + align:start position:0% +this start with sinx in the real case + + + align:start position:0% +this start with sinx in the real case +develop its convergent power series take + + align:start position:0% +develop its convergent power series take + + + align:start position:0% +develop its convergent power series take +that power series + + align:start position:0% +that power series + + + align:start position:0% +that power series +replace X by Z and Define that new + + align:start position:0% +replace X by Z and Define that new + + + align:start position:0% +replace X by Z and Define that new +complex power series to be what sin Z is + + align:start position:0% +complex power series to be what sin Z is + + + align:start position:0% +complex power series to be what sin Z is +and that gets the job done for you now + + align:start position:0% +and that gets the job done for you now + + + align:start position:0% +and that gets the job done for you now +the interesting thing is that one can + + align:start position:0% +the interesting thing is that one can + + + align:start position:0% +the interesting thing is that one can +now show that all of the trigonometric + + align:start position:0% +now show that all of the trigonometric + + + align:start position:0% +now show that all of the trigonometric +functions be they hyperbolic or circular + + align:start position:0% +functions be they hyperbolic or circular + + + align:start position:0% +functions be they hyperbolic or circular +functions are related to e to the Z well + + align:start position:0% +functions are related to e to the Z well + + + align:start position:0% +functions are related to e to the Z well +why that's interesting is not very + + align:start position:0% +why that's interesting is not very + + + align:start position:0% +why that's interesting is not very +important right now it's we'll mention + + align:start position:0% +important right now it's we'll mention + + + align:start position:0% +important right now it's we'll mention +that in more detail on other occasions + + align:start position:0% +that in more detail on other occasions + + + align:start position:0% +that in more detail on other occasions +hopefully but the idea is this by using + + align:start position:0% +hopefully but the idea is this by using + + + align:start position:0% +hopefully but the idea is this by using +the fact that these various series are + + align:start position:0% +the fact that these various series are + + + align:start position:0% +the fact that these various series are +absolutely and uniformly convergent so I + + align:start position:0% +absolutely and uniformly convergent so I + + + align:start position:0% +absolutely and uniformly convergent so I +can manipulate them term by term and + + align:start position:0% +can manipulate them term by term and + + + align:start position:0% +can manipulate them term by term and +these things are done in detail in the + + align:start position:0% +these things are done in detail in the + + + align:start position:0% +these things are done in detail in the +text and I will give you other ones to + + align:start position:0% +text and I will give you other ones to + + + align:start position:0% +text and I will give you other ones to +do for homework so that you get the + + align:start position:0% +do for homework so that you get the + + + align:start position:0% +do for homework so that you get the +drill on this one can show the very + + align:start position:0% +drill on this one can show the very + + + align:start position:0% +drill on this one can show the very +amazing result that e to the i z is + + align:start position:0% +amazing result that e to the i z is + + + align:start position:0% +amazing result that e to the i z is +cosine Z plus I sin z a very amazing + + align:start position:0% +cosine Z plus I sin z a very amazing + + + align:start position:0% +cosine Z plus I sin z a very amazing +result it relates the cosine and the + + align:start position:0% +result it relates the cosine and the + + + align:start position:0% +result it relates the cosine and the +sign to an exponential in fact to stress + + align:start position:0% +sign to an exponential in fact to stress + + + align:start position:0% +sign to an exponential in fact to stress +this from a different point of view if I + + align:start position:0% +this from a different point of view if I + + + align:start position:0% +this from a different point of view if I +take the special case that Z is real + + align:start position:0% +take the special case that Z is real + + + align:start position:0% +take the special case that Z is real +notice that this says what e to the iix + + align:start position:0% +notice that this says what e to the iix + + + align:start position:0% +notice that this says what e to the iix +see replace Z byx is cinx plus I + + align:start position:0% +see replace Z byx is cinx plus I + + + align:start position:0% +see replace Z byx is cinx plus I +sinx okay in particular what this then + + align:start position:0% +sinx okay in particular what this then + + + align:start position:0% +sinx okay in particular what this then +says is let's go back to the Aon diagram + + align:start position:0% +says is let's go back to the Aon diagram + + + align:start position:0% +says is let's go back to the Aon diagram +where we take the complex number view it + + align:start position:0% +where we take the complex number view it + + + align:start position:0% +where we take the complex number view it +in polar coordinates as R comma Theta + + align:start position:0% +in polar coordinates as R comma Theta + + + align:start position:0% +in polar coordinates as R comma Theta +which means what R cosine theta plus i r + + align:start position:0% +which means what R cosine theta plus i r + + + align:start position:0% +which means what R cosine theta plus i r +sin Theta factor out the R so R * cosine + + align:start position:0% +sin Theta factor out the R so R * cosine + + + align:start position:0% +sin Theta factor out the R so R * cosine +theta plus I sin Theta but cine theta + + align:start position:0% +theta plus I sin Theta but cine theta + + + align:start position:0% +theta plus I sin Theta but cine theta +plus I sin Theta is e to the I Theta and + + align:start position:0% +plus I sin Theta is e to the I Theta and + + + align:start position:0% +plus I sin Theta is e to the I Theta and +what that says is that if you really + + align:start position:0% +what that says is that if you really + + + align:start position:0% +what that says is that if you really +wanted a nice name for this R comma + + align:start position:0% +wanted a nice name for this R comma + + + align:start position:0% +wanted a nice name for this R comma +Theta does turn out in the language of + + align:start position:0% +Theta does turn out in the language of + + + align:start position:0% +Theta does turn out in the language of +polar coordinates using complex + + align:start position:0% +polar coordinates using complex + + + align:start position:0% +polar coordinates using complex +variables without cartisian reference is + + align:start position:0% +variables without cartisian reference is + + + align:start position:0% +variables without cartisian reference is +re e to the I Theta which by the way + + align:start position:0% +re e to the I Theta which by the way + + + align:start position:0% +re e to the I Theta which by the way +would explain very nicely why when you + + align:start position:0% +would explain very nicely why when you + + + align:start position:0% +would explain very nicely why when you +multiply complex numbers you multiply + + align:start position:0% +multiply complex numbers you multiply + + + align:start position:0% +multiply complex numbers you multiply +the magnitude and add the arguments + + align:start position:0% +the magnitude and add the arguments + + + align:start position:0% +the magnitude and add the arguments +namely notice that the magnitudes are + + align:start position:0% +namely notice that the magnitudes are + + + align:start position:0% +namely notice that the magnitudes are +these scal factors in front of the + + align:start position:0% +these scal factors in front of the + + + align:start position:0% +these scal factors in front of the +exponential the arguments occur as + + align:start position:0% +exponential the arguments occur as + + + align:start position:0% +exponential the arguments occur as +exponents and when you multiply two + + align:start position:0% +exponents and when you multiply two + + + align:start position:0% +exponents and when you multiply two +numbers to the base e you add the + + align:start position:0% +numbers to the base e you add the + + + align:start position:0% +numbers to the base e you add the +exponents in fact when you multiply + + align:start position:0% +exponents in fact when you multiply + + + align:start position:0% +exponents in fact when you multiply +numbers to any base you add the + + align:start position:0% +numbers to any base you add the + + + align:start position:0% +numbers to any base you add the +exponents and that's why you add the + + align:start position:0% +exponents and that's why you add the + + + align:start position:0% +exponents and that's why you add the +angles over here uh again a very + + align:start position:0% +angles over here uh again a very + + + align:start position:0% +angles over here uh again a very +interesting side which is worth + + align:start position:0% +interesting side which is worth + + + align:start position:0% +interesting side which is worth +absolutely nothing but I always I think + + align:start position:0% +absolutely nothing but I always I think + + + align:start position:0% +absolutely nothing but I always I think +it was the first thing that ever turned + + align:start position:0% +it was the first thing that ever turned + + + align:start position:0% +it was the first thing that ever turned +me on in mathematics that get my + + align:start position:0% +me on in mathematics that get my + + + align:start position:0% +me on in mathematics that get my +metaphysical mathematical dander up was + + align:start position:0% +metaphysical mathematical dander up was + + + align:start position:0% +metaphysical mathematical dander up was +if you replace X + + align:start position:0% +if you replace X + + + align:start position:0% +if you replace X +by pi over here see what does that mean + + align:start position:0% +by pi over here see what does that mean + + + align:start position:0% +by pi over here see what does that mean +if I replace X by pi the magnitude is + + align:start position:0% +if I replace X by pi the magnitude is + + + align:start position:0% +if I replace X by pi the magnitude is +one the angle is pi e to the I + + align:start position:0% +one the angle is pi e to the I + + + align:start position:0% +one the angle is pi e to the I +Pi e to the I + + align:start position:0% + + + + align:start position:0% + +Pi is just another way of writing minus + + align:start position:0% +Pi is just another way of writing minus + + + align:start position:0% +Pi is just another way of writing minus +one see what is e to the I Pi the + + align:start position:0% +one see what is e to the I Pi the + + + align:start position:0% +one see what is e to the I Pi the +argument is pi that means 180° the + + align:start position:0% +argument is pi that means 180° the + + + align:start position:0% +argument is pi that means 180° the +argument is one and the number which is + + align:start position:0% +argument is one and the number which is + + + align:start position:0% +argument is one and the number which is +one unit from the origin in the Aon + + align:start position:0% +one unit from the origin in the Aon + + + align:start position:0% +one unit from the origin in the Aon +diagram at an angle of 180° is the real + + align:start position:0% +diagram at an angle of 180° is the real + + + align:start position:0% +diagram at an angle of 180° is the real +number minus one and I've always been + + align:start position:0% +number minus one and I've always been + + + align:start position:0% +number minus one and I've always been +mystified by the three most remarkable + + align:start position:0% +mystified by the three most remarkable + + + align:start position:0% +mystified by the three most remarkable +numbers constants in mathematics seem to + + align:start position:0% +numbers constants in mathematics seem to + + + align:start position:0% +numbers constants in mathematics seem to +be EI I and pi and e to the I Pi turns + + align:start position:0% +be EI I and pi and e to the I Pi turns + + + align:start position:0% +be EI I and pi and e to the I Pi turns +out to be minus one I just mentioned + + align:start position:0% +out to be minus one I just mentioned + + + align:start position:0% +out to be minus one I just mentioned +this to show you how complicated things + + align:start position:0% +this to show you how complicated things + + + align:start position:0% +this to show you how complicated things +can get if you try to read too much + + align:start position:0% +can get if you try to read too much + + + align:start position:0% +can get if you try to read too much +meaning into things but don't worry + + align:start position:0% +meaning into things but don't worry + + + align:start position:0% +meaning into things but don't worry +about that right now I couldn't resist + + align:start position:0% +about that right now I couldn't resist + + + align:start position:0% +about that right now I couldn't resist +the comment what I would like to do + + align:start position:0% +the comment what I would like to do + + + align:start position:0% +the comment what I would like to do +though is to show you now how this is + + align:start position:0% +though is to show you now how this is + + + align:start position:0% +though is to show you now how this is +used to define other functions and get + + align:start position:0% +used to define other functions and get + + + align:start position:0% +used to define other functions and get +us other results among other things + + align:start position:0% +us other results among other things + + + align:start position:0% +us other results among other things +notice that the first bad thing that + + align:start position:0% +notice that the first bad thing that + + + align:start position:0% +notice that the first bad thing that +happens with the polar coordinate + + align:start position:0% +happens with the polar coordinate + + + align:start position:0% +happens with the polar coordinate +representation is if the complex number + + align:start position:0% +representation is if the complex number + + + align:start position:0% +representation is if the complex number +Z can be written as re e to the I Theta + + align:start position:0% +Z can be written as re e to the I Theta + + + align:start position:0% +Z can be written as re e to the I Theta +it can also be written as re e to the I + + align:start position:0% +it can also be written as re e to the I + + + align:start position:0% +it can also be written as re e to the I +Theta + 2 pi K because every time I + + align:start position:0% +Theta + 2 pi K because every time I + + + align:start position:0% +Theta + 2 pi K because every time I +change my angle by 2 pi or + + align:start position:0% +change my angle by 2 pi or + + + align:start position:0% +change my angle by 2 pi or +360° I come back to the same Point again + + align:start position:0% +360° I come back to the same Point again + + + align:start position:0% +360° I come back to the same Point again +at any rate forgetting about that + + align:start position:0% +at any rate forgetting about that + + + align:start position:0% +at any rate forgetting about that +problem for the time being notice how I + + align:start position:0% +problem for the time being notice how I + + + align:start position:0% +problem for the time being notice how I +can now Define a logarithm for a complex + + align:start position:0% +can now Define a logarithm for a complex + + + align:start position:0% +can now Define a logarithm for a complex +number in fact the logarithm will turn + + align:start position:0% +number in fact the logarithm will turn + + + align:start position:0% +number in fact the logarithm will turn +out to be the inverse of e to the Z the + + align:start position:0% +out to be the inverse of e to the Z the + + + align:start position:0% +out to be the inverse of e to the Z the +same as before but we won't worry about + + align:start position:0% +same as before but we won't worry about + + + align:start position:0% +same as before but we won't worry about +that here either let's see how we could + + align:start position:0% +that here either let's see how we could + + + align:start position:0% +that here either let's see how we could +Define log Z from this now we would like + + align:start position:0% +Define log Z from this now we would like + + + align:start position:0% +Define log Z from this now we would like +the log to have the usual logarithmic + + align:start position:0% +the log to have the usual logarithmic + + + align:start position:0% +the log to have the usual logarithmic +properties the log of a product should + + align:start position:0% +properties the log of a product should + + + align:start position:0% +properties the log of a product should +be the sum of the logi the the sum of + + align:start position:0% +be the sum of the logi the the sum of + + + align:start position:0% +be the sum of the logi the the sum of +the logs so log Z should be log R plus + + align:start position:0% +the logs so log Z should be log R plus + + + align:start position:0% +the logs so log Z should be log R plus +log e to the I Theta + 2 pi k now R is a + + align:start position:0% +log e to the I Theta + 2 pi k now R is a + + + align:start position:0% +log e to the I Theta + 2 pi k now R is a +positive real number we already know + + align:start position:0% +positive real number we already know + + + align:start position:0% +positive real number we already know +that the natural log applies there so + + align:start position:0% +that the natural log applies there so + + + align:start position:0% +that the natural log applies there so +the N so what we say is okay the log of + + align:start position:0% +the N so what we say is okay the log of + + + align:start position:0% +the N so what we say is okay the log of +R is just natural log R log e to + + align:start position:0% +R is just natural log R log e to + + + align:start position:0% +R is just natural log R log e to +anything the log and the E are inverse + + align:start position:0% +anything the log and the E are inverse + + + align:start position:0% +anything the log and the E are inverse +of one another so they should cancel and + + align:start position:0% +of one another so they should cancel and + + + align:start position:0% +of one another so they should cancel and +this should just be I Theta + 2 pi K in + + align:start position:0% +this should just be I Theta + 2 pi K in + + + align:start position:0% +this should just be I Theta + 2 pi K in +other words to find the log of the + + align:start position:0% +other words to find the log of the + + + align:start position:0% +other words to find the log of the +complex number Z you simply take the log + + align:start position:0% +complex number Z you simply take the log + + + align:start position:0% +complex number Z you simply take the log +of its magnitude and add on as the + + align:start position:0% +of its magnitude and add on as the + + + align:start position:0% +of its magnitude and add on as the +imaginary part what the argument + + align:start position:0% +imaginary part what the argument + + + align:start position:0% +imaginary part what the argument +noticing by the way that the argument is + + align:start position:0% +noticing by the way that the argument is + + + align:start position:0% +noticing by the way that the argument is +multivalued see log Z is multivalued + + align:start position:0% +multivalued see log Z is multivalued + + + align:start position:0% +multivalued see log Z is multivalued +consequently we must get into the idea + + align:start position:0% +consequently we must get into the idea + + + align:start position:0% +consequently we must get into the idea +of principal values and one usually + + align:start position:0% +of principal values and one usually + + + align:start position:0% +of principal values and one usually +assumes unless otherwise stated that the + + align:start position:0% +assumes unless otherwise stated that the + + + align:start position:0% +assumes unless otherwise stated that the +argument is at no greater than Pi but + + align:start position:0% +argument is at no greater than Pi but + + + align:start position:0% +argument is at no greater than Pi but +greater than minus Pi if we don't mean + + align:start position:0% +greater than minus Pi if we don't mean + + + align:start position:0% +greater than minus Pi if we don't mean +that we have to state that separately + + align:start position:0% +that we have to state that separately + + + align:start position:0% +that we have to state that separately +again we will drill on that in the + + align:start position:0% +again we will drill on that in the + + + align:start position:0% +again we will drill on that in the +exercises by the way another application + + align:start position:0% +exercises by the way another application + + + align:start position:0% +exercises by the way another application +that relates the hyperbolic functions to + + align:start position:0% +that relates the hyperbolic functions to + + + align:start position:0% +that relates the hyperbolic functions to +the tri metric to the circular functions + + align:start position:0% +the tri metric to the circular functions + + + align:start position:0% +the tri metric to the circular functions +notice that if we wanted to Define + + align:start position:0% +notice that if we wanted to Define + + + align:start position:0% +notice that if we wanted to Define +hyperbolic cosine of IX mimicking what + + align:start position:0% +hyperbolic cosine of IX mimicking what + + + align:start position:0% +hyperbolic cosine of IX mimicking what +happened in the real case this would be + + align:start position:0% +happened in the real case this would be + + + align:start position:0% +happened in the real case this would be +e to the IX plus e to minus IX over 2 we + + align:start position:0% +e to the IX plus e to minus IX over 2 we + + + align:start position:0% +e to the IX plus e to minus IX over 2 we +already saw that e to the IX was cinx + + + align:start position:0% +already saw that e to the IX was cinx + + + + align:start position:0% +already saw that e to the IX was cinx + +i sinx e to Theus IX is e to the I of - + + align:start position:0% +i sinx e to Theus IX is e to the I of - + + + align:start position:0% +i sinx e to Theus IX is e to the I of - +x that's cosine - x plus I sin - x by + + align:start position:0% +x that's cosine - x plus I sin - x by + + + align:start position:0% +x that's cosine - x plus I sin - x by +the way I hope that's clear to you when + + align:start position:0% +the way I hope that's clear to you when + + + align:start position:0% +the way I hope that's clear to you when +I say that e to the iix is cine X plus I + + align:start position:0% +I say that e to the iix is cine X plus I + + + align:start position:0% +I say that e to the iix is cine X plus I +sinx what I really mean is or even up + + align:start position:0% +sinx what I really mean is or even up + + + align:start position:0% +sinx what I really mean is or even up +here what I really mean is that e to the + + align:start position:0% +here what I really mean is that e to the + + + align:start position:0% +here what I really mean is that e to the +I anything is cosine of that anything + + align:start position:0% +I anything is cosine of that anything + + + align:start position:0% +I anything is cosine of that anything +plus I S of that anything in particular + + align:start position:0% +plus I S of that anything in particular + + + align:start position:0% +plus I S of that anything in particular +if I replace Z by minus X I get e to the + + align:start position:0% +if I replace Z by minus X I get e to the + + + align:start position:0% +if I replace Z by minus X I get e to the +i - x in other words- IX is cosine - x + + align:start position:0% +i - x in other words- IX is cosine - x + + + align:start position:0% +i - x in other words- IX is cosine - x +plus I sin - + + align:start position:0% +plus I sin - + + + align:start position:0% +plus I sin - +x okay and notice that cosine of - x + + align:start position:0% +x okay and notice that cosine of - x + + + align:start position:0% +x okay and notice that cosine of - x +equal cosine X X sin - x is- sin x these + + align:start position:0% +equal cosine X X sin - x is- sin x these + + + align:start position:0% +equal cosine X X sin - x is- sin x these +terms cancel this becomes 2 cosine x 2 + + align:start position:0% +terms cancel this becomes 2 cosine x 2 + + + align:start position:0% +terms cancel this becomes 2 cosine x 2 +cosine X ID 2 is cosine X and we have + + align:start position:0% +cosine X ID 2 is cosine X and we have + + + align:start position:0% +cosine X ID 2 is cosine X and we have +the rather amazing identity that K IX is + + align:start position:0% +the rather amazing identity that K IX is + + + align:start position:0% +the rather amazing identity that K IX is +cine X in other words a very interesting + + align:start position:0% +cine X in other words a very interesting + + + align:start position:0% +cine X in other words a very interesting +relationship between the hyperbolic and + + align:start position:0% +relationship between the hyperbolic and + + + align:start position:0% +relationship between the hyperbolic and +the circular functions and by the way + + align:start position:0% +the circular functions and by the way + + + align:start position:0% +the circular functions and by the way +this shouldn't be too + + align:start position:0% +this shouldn't be too + + + align:start position:0% +this shouldn't be too +surprising notice that the circular + + align:start position:0% +surprising notice that the circular + + + align:start position:0% +surprising notice that the circular +functions come from studying x² + + align:start position:0% +functions come from studying x² + + + align:start position:0% +functions come from studying x² ++ + + align:start position:0% ++ + + + align:start position:0% ++ +y^2 = 1 the hyperbolic functions come + + align:start position:0% +y^2 = 1 the hyperbolic functions come + + + align:start position:0% +y^2 = 1 the hyperbolic functions come +from studying x^2 - Y2 = 1 and x^2 - y^2 + + align:start position:0% +from studying x^2 - Y2 = 1 and x^2 - y^2 + + + align:start position:0% +from studying x^2 - Y2 = 1 and x^2 - y^2 +can be written as x^2 plus the quantity + + align:start position:0% +can be written as x^2 plus the quantity + + + align:start position:0% +can be written as x^2 plus the quantity +I y^2 so what would be a a hyperbola in + + align:start position:0% +I y^2 so what would be a a hyperbola in + + + align:start position:0% +I y^2 so what would be a a hyperbola in +the XY plane would be a circle in the x + + align:start position:0% +the XY plane would be a circle in the x + + + align:start position:0% +the XY plane would be a circle in the x +i y plane whatever that might be but + + align:start position:0% +i y plane whatever that might be but + + + align:start position:0% +i y plane whatever that might be but +again that's just in the form of an + + align:start position:0% +again that's just in the form of an + + + align:start position:0% +again that's just in the form of an +aside and now we'll come back to we mean + + align:start position:0% +aside and now we'll come back to we mean + + + align:start position:0% +aside and now we'll come back to we mean +by saying that we can use these new + + align:start position:0% +by saying that we can use these new + + + align:start position:0% +by saying that we can use these new +analytic functions to do conformal + + align:start position:0% +analytic functions to do conformal + + + align:start position:0% +analytic functions to do conformal +mappings let's come back to the question + + align:start position:0% +mappings let's come back to the question + + + align:start position:0% +mappings let's come back to the question +that we raised at the very beginning of + + align:start position:0% +that we raised at the very beginning of + + + align:start position:0% +that we raised at the very beginning of +our lecture about e to the + + align:start position:0% +our lecture about e to the + + + align:start position:0% +our lecture about e to the +Z certainly because Z is X+ i y e to the + + align:start position:0% +Z certainly because Z is X+ i y e to the + + + align:start position:0% +Z certainly because Z is X+ i y e to the +Z will be e to X Plus i y because of the + + align:start position:0% +Z will be e to X Plus i y because of the + + + align:start position:0% +Z will be e to X Plus i y because of the +properties that the exponential will + + align:start position:0% +properties that the exponential will + + + align:start position:0% +properties that the exponential will +have and by the way all of these + + align:start position:0% +have and by the way all of these + + + align:start position:0% +have and by the way all of these +exponential properties can be proven + + align:start position:0% +exponential properties can be proven + + + align:start position:0% +exponential properties can be proven +from the power series you see we don't + + align:start position:0% +from the power series you see we don't + + + align:start position:0% +from the power series you see we don't +need the real interpretation the power + + align:start position:0% +need the real interpretation the power + + + align:start position:0% +need the real interpretation the power +series will give us all the these + + align:start position:0% +series will give us all the these + + + align:start position:0% +series will give us all the these +results but again we'll drill on those + + align:start position:0% +results but again we'll drill on those + + + align:start position:0% +results but again we'll drill on those +in the exercises I just want to get the + + align:start position:0% +in the exercises I just want to get the + + + align:start position:0% +in the exercises I just want to get the +Highlights here this is e to x * e to + + align:start position:0% +Highlights here this is e to x * e to + + + align:start position:0% +Highlights here this is e to x * e to +the i y but notice here you see that Y + + align:start position:0% +the i y but notice here you see that Y + + + align:start position:0% +the i y but notice here you see that Y +is real and for even if it wasn't real + + align:start position:0% +is real and for even if it wasn't real + + + align:start position:0% +is real and for even if it wasn't real +it doesn't make any difference e to the + + align:start position:0% +it doesn't make any difference e to the + + + align:start position:0% +it doesn't make any difference e to the +i y is cosine y + I sin y multiplying + + align:start position:0% +i y is cosine y + I sin y multiplying + + + align:start position:0% +i y is cosine y + I sin y multiplying +this out e to the Z is e to x cosine y + + align:start position:0% +this out e to the Z is e to x cosine y + + + align:start position:0% +this out e to the Z is e to x cosine y +plus I E to X sin y the important thing + + align:start position:0% +plus I E to X sin y the important thing + + + align:start position:0% +plus I E to X sin y the important thing +being that because Y is real e to the x + + align:start position:0% +being that because Y is real e to the x + + + align:start position:0% +being that because Y is real e to the x +cosine y and e to X X sin y are both + + align:start position:0% +cosine y and e to X X sin y are both + + + align:start position:0% +cosine y and e to X X sin y are both +real and consequently if I let U denote + + align:start position:0% +real and consequently if I let U denote + + + align:start position:0% +real and consequently if I let U denote +the real part and V denote the imaginary + + align:start position:0% +the real part and V denote the imaginary + + + align:start position:0% +the real part and V denote the imaginary +part as usual what I have is that u = e + + align:start position:0% +part as usual what I have is that u = e + + + align:start position:0% +part as usual what I have is that u = e +to x cosine y v = e to X sin Y Must Be a + + align:start position:0% +to x cosine y v = e to X sin Y Must Be a + + + align:start position:0% +to x cosine y v = e to X sin Y Must Be a +Real conformal mapping why because the + + align:start position:0% +Real conformal mapping why because the + + + align:start position:0% +Real conformal mapping why because the +real and the imaginary Parts the real + + align:start position:0% +real and the imaginary Parts the real + + + align:start position:0% +real and the imaginary Parts the real +and the imaginary parts make up an + + align:start position:0% +and the imaginary parts make up an + + + align:start position:0% +and the imaginary parts make up an +analytic function how do I know this + + align:start position:0% +analytic function how do I know this + + + align:start position:0% +analytic function how do I know this +function is analytic because its power + + align:start position:0% +function is analytic because its power + + + align:start position:0% +function is analytic because its power +series exists and the fact that it's + + align:start position:0% +series exists and the fact that it's + + + align:start position:0% +series exists and the fact that it's +power series exists means that all the + + align:start position:0% +power series exists means that all the + + + align:start position:0% +power series exists means that all the +derivatives must exist now again I + + align:start position:0% +derivatives must exist now again I + + + align:start position:0% +derivatives must exist now again I +didn't write this in here but maybe it's + + align:start position:0% +didn't write this in here but maybe it's + + + align:start position:0% +didn't write this in here but maybe it's +a worthwhile asside to show you what + + align:start position:0% +a worthwhile asside to show you what + + + align:start position:0% +a worthwhile asside to show you what +this conformal mapping looks like for + + align:start position:0% +this conformal mapping looks like for + + + align:start position:0% +this conformal mapping looks like for +example notice that if I Square both + + align:start position:0% +example notice that if I Square both + + + align:start position:0% +example notice that if I Square both +sides of each equation here and add if I + + align:start position:0% +sides of each equation here and add if I + + + align:start position:0% +sides of each equation here and add if I +square and add what do I get on one side + + align:start position:0% +square and add what do I get on one side + + + align:start position:0% +square and add what do I get on one side +I get u^2 + v^2 on the other side I get + + align:start position:0% +I get u^2 + v^2 on the other side I get + + + align:start position:0% +I get u^2 + v^2 on the other side I get +e 2x cosine 2 y plus e 2x sin^2 y i I + + align:start position:0% +e 2x cosine 2 y plus e 2x sin^2 y i I + + + align:start position:0% +e 2x cosine 2 y plus e 2x sin^2 y i I +factor out e 2X and that gives me e 2x + + align:start position:0% +factor out e 2X and that gives me e 2x + + + align:start position:0% +factor out e 2X and that gives me e 2x +sin^2 y + cosine ^ 2 Y which is 1 so + + align:start position:0% +sin^2 y + cosine ^ 2 Y which is 1 so + + + align:start position:0% +sin^2 y + cosine ^ 2 Y which is 1 so +this is just U ^2 + v^2 is e 2x to + + align:start position:0% +this is just U ^2 + v^2 is e 2x to + + + align:start position:0% +this is just U ^2 + v^2 is e 2x to +eliminate X from the equations I can + + align:start position:0% +eliminate X from the equations I can + + + align:start position:0% +eliminate X from the equations I can +divide the Bottom by the top and I get + + align:start position:0% +divide the Bottom by the top and I get + + + align:start position:0% +divide the Bottom by the top and I get +that V over + + align:start position:0% +that V over + + + align:start position:0% +that V over +u v/ u is equal to tangent + + align:start position:0% +u v/ u is equal to tangent + + + align:start position:0% +u v/ u is equal to tangent +Y and by the way notice what this thing + + align:start position:0% +Y and by the way notice what this thing + + + align:start position:0% +Y and by the way notice what this thing +tells me this tells me see what are the + + align:start position:0% +tells me this tells me see what are the + + + align:start position:0% +tells me this tells me see what are the +uh basic lines in the XY plane that the + + align:start position:0% +uh basic lines in the XY plane that the + + + align:start position:0% +uh basic lines in the XY plane that the +lines x equal a constant y equals a + + align:start position:0% +lines x equal a constant y equals a + + + align:start position:0% +lines x equal a constant y equals a +constant notice that if x is a constant + + align:start position:0% +constant notice that if x is a constant + + + align:start position:0% +constant notice that if x is a constant +this says that U ^2 + v^2 = e to a + + align:start position:0% +this says that U ^2 + v^2 = e to a + + + align:start position:0% +this says that U ^2 + v^2 = e to a +constant power that's u^2 + v^2 is a + + align:start position:0% +constant power that's u^2 + v^2 is a + + + align:start position:0% +constant power that's u^2 + v^2 is a +constant that's a circle centered at the + + align:start position:0% +constant that's a circle centered at the + + + align:start position:0% +constant that's a circle centered at the +origin in other words the lines x equal + + align:start position:0% +origin in other words the lines x equal + + + align:start position:0% +origin in other words the lines x equal +a constant map into concentric circles + + align:start position:0% +a constant map into concentric circles + + + align:start position:0% +a constant map into concentric circles +on the other hand if Y is a constant + + align:start position:0% +on the other hand if Y is a constant + + + align:start position:0% +on the other hand if Y is a constant +this says that v/ U is a constant in the + + align:start position:0% +this says that v/ U is a constant in the + + + align:start position:0% +this says that v/ U is a constant in the +UV V plane v/ U is a constant is a + + align:start position:0% +UV V plane v/ U is a constant is a + + + align:start position:0% +UV V plane v/ U is a constant is a +straight line that goes through the + + align:start position:0% +straight line that goes through the + + + align:start position:0% +straight line that goes through the +origin see V is a constant times U now + + align:start position:0% +origin see V is a constant times U now + + + align:start position:0% +origin see V is a constant times U now +what that means pictorially let's see if + + align:start position:0% +what that means pictorially let's see if + + + align:start position:0% +what that means pictorially let's see if +I have some room to squeeze this in here + + align:start position:0% +I have some room to squeeze this in here + + + align:start position:0% +I have some room to squeeze this in here +what this means pictorially is that this + + align:start position:0% +what this means pictorially is that this + + + align:start position:0% +what this means pictorially is that this +kind of a + + align:start position:0% +kind of a + + + align:start position:0% +kind of a +network see in the XY + + align:start position:0% +network see in the XY + + + align:start position:0% +network see in the XY +plane this kind of a network in the XY + + align:start position:0% +plane this kind of a network in the XY + + + align:start position:0% +plane this kind of a network in the XY +plane is mapped into what this network + + align:start position:0% +plane is mapped into what this network + + + align:start position:0% +plane is mapped into what this network +is mapped into a what the vertical lines + + align:start position:0% +is mapped into a what the vertical lines + + + align:start position:0% +is mapped into a what the vertical lines +go into concentric circles and the + + align:start position:0% +go into concentric circles and the + + + align:start position:0% +go into concentric circles and the +horizontal lines go in into lines + + align:start position:0% +horizontal lines go in into lines + + + align:start position:0% +horizontal lines go in into lines +through the origin here and not + + align:start position:0% +through the origin here and not + + + align:start position:0% +through the origin here and not +okay notice by the way that every line + + align:start position:0% +okay notice by the way that every line + + + align:start position:0% +okay notice by the way that every line +through the origin meets The Circle at + + align:start position:0% +through the origin meets The Circle at + + + align:start position:0% +through the origin meets The Circle at +right + + align:start position:0% +right + + + align:start position:0% +right +angles notice that these lines were at + + align:start position:0% +angles notice that these lines were at + + + align:start position:0% +angles notice that these lines were at +right angles here notice the conformal + + align:start position:0% +right angles here notice the conformal + + + align:start position:0% +right angles here notice the conformal +property here in other words lines that + + align:start position:0% +property here in other words lines that + + + align:start position:0% +property here in other words lines that +meet at right angle in the XY plane must + + align:start position:0% +meet at right angle in the XY plane must + + + align:start position:0% +meet at right angle in the XY plane must +meet at right angles in the UV plane and + + align:start position:0% +meet at right angles in the UV plane and + + + align:start position:0% +meet at right angles in the UV plane and +let me separate this out from anything + + align:start position:0% +let me separate this out from anything + + + align:start position:0% +let me separate this out from anything +else that I've done so that we don't get + + align:start position:0% +else that I've done so that we don't get + + + align:start position:0% +else that I've done so that we don't get +too mixed up with this by the way one of + + align:start position:0% +too mixed up with this by the way one of + + + align:start position:0% +too mixed up with this by the way one of +the ways that this is used in + + align:start position:0% +the ways that this is used in + + + align:start position:0% +the ways that this is used in +application is with the inverse mapping + + align:start position:0% +application is with the inverse mapping + + + align:start position:0% +application is with the inverse mapping +that in certain cases where we have to + + align:start position:0% +that in certain cases where we have to + + + align:start position:0% +that in certain cases where we have to +deal with regions that have this kind of + + align:start position:0% +deal with regions that have this kind of + + + align:start position:0% +deal with regions that have this kind of +a + + align:start position:0% +a + + + align:start position:0% +a +shape we back map this region and what + + align:start position:0% +shape we back map this region and what + + + align:start position:0% +shape we back map this region and what +will it go into it'll go into a + + align:start position:0% +will it go into it'll go into a + + + align:start position:0% +will it go into it'll go into a +rectangle here and for example in + + align:start position:0% +rectangle here and for example in + + + align:start position:0% +rectangle here and for example in +solving Lassa equation it might be a lot + + align:start position:0% +solving Lassa equation it might be a lot + + + align:start position:0% +solving Lassa equation it might be a lot +easier to solve lass's equation on the + + align:start position:0% +easier to solve lass's equation on the + + + align:start position:0% +easier to solve lass's equation on the +boundary of a rectangle than on the + + align:start position:0% +boundary of a rectangle than on the + + + align:start position:0% +boundary of a rectangle than on the +boundary of a region of this particular + + align:start position:0% +boundary of a region of this particular + + + align:start position:0% +boundary of a region of this particular +type again I don't want to go into too + + align:start position:0% +type again I don't want to go into too + + + align:start position:0% +type again I don't want to go into too +much detail here because it obscures + + align:start position:0% +much detail here because it obscures + + + align:start position:0% +much detail here because it obscures +what the main overview is namely every + + align:start position:0% +what the main overview is namely every + + + align:start position:0% +what the main overview is namely every +time we invent an analytic function like + + align:start position:0% +time we invent an analytic function like + + + align:start position:0% +time we invent an analytic function like +e to the Z sin Z cos Z Etc we have + + align:start position:0% +e to the Z sin Z cos Z Etc we have + + + align:start position:0% +e to the Z sin Z cos Z Etc we have +invented a new conformal mapping where + + align:start position:0% +invented a new conformal mapping where + + + align:start position:0% +invented a new conformal mapping where +that conformal mapping will help us in a + + align:start position:0% +that conformal mapping will help us in a + + + align:start position:0% +that conformal mapping will help us in a +particular application or not depends on + + align:start position:0% +particular application or not depends on + + + align:start position:0% +particular application or not depends on +the application but what the meaning of + + align:start position:0% +the application but what the meaning of + + + align:start position:0% +the application but what the meaning of +it is is independent of any application + + align:start position:0% +it is is independent of any application + + + align:start position:0% +it is is independent of any application +okay now let's take one more important + + align:start position:0% +okay now let's take one more important + + + align:start position:0% +okay now let's take one more important +reason you see what I'm afraid of now is + + align:start position:0% +reason you see what I'm afraid of now is + + + align:start position:0% +reason you see what I'm afraid of now is +I'm giving you the impression that + + align:start position:0% +I'm giving you the impression that + + + align:start position:0% +I'm giving you the impression that +complex numbers have value only if + + align:start position:0% +complex numbers have value only if + + + align:start position:0% +complex numbers have value only if +you're doing conformal mappings you see + + align:start position:0% +you're doing conformal mappings you see + + + align:start position:0% +you're doing conformal mappings you see +con complex numbers give you a degree of + + align:start position:0% +con complex numbers give you a degree of + + + align:start position:0% +con complex numbers give you a degree of +Consciousness so to speak above the real + + align:start position:0% +Consciousness so to speak above the real + + + align:start position:0% +Consciousness so to speak above the real +numbers let me give you an example of + + align:start position:0% +numbers let me give you an example of + + + align:start position:0% +numbers let me give you an example of +another problem that used to hang me up + + align:start position:0% +another problem that used to hang me up + + + align:start position:0% +another problem that used to hang me up +when I was an undergraduate student + + align:start position:0% +when I was an undergraduate student + + + align:start position:0% +when I was an undergraduate student +learning calculus I'm going to apply + + align:start position:0% +learning calculus I'm going to apply + + + align:start position:0% +learning calculus I'm going to apply +complex Val results to real series now + + align:start position:0% +complex Val results to real series now + + + align:start position:0% +complex Val results to real series now +remember the geometric series 1/ 1 - U + + align:start position:0% +remember the geometric series 1/ 1 - U + + + align:start position:0% +remember the geometric series 1/ 1 - U +is 1 + U + U ^2 Etc in other words + + align:start position:0% +is 1 + U + U ^2 Etc in other words + + + align:start position:0% +is 1 + U + U ^2 Etc in other words +summation n goes from 0 to Infinity U + + align:start position:0% +summation n goes from 0 to Infinity U + + + align:start position:0% +summation n goes from 0 to Infinity U +the n and that converges for the + + align:start position:0% +the n and that converges for the + + + align:start position:0% +the n and that converges for the +absolute value of U less than one let's + + align:start position:0% +absolute value of U less than one let's + + + align:start position:0% +absolute value of U less than one let's +suppose now I replace U by - x^2 if I do + + align:start position:0% +suppose now I replace U by - x^2 if I do + + + align:start position:0% +suppose now I replace U by - x^2 if I do +that I get 1 over 1 + x^2 is 1 - x^2 + x + + align:start position:0% +that I get 1 over 1 + x^2 is 1 - x^2 + x + + + align:start position:0% +that I get 1 over 1 + x^2 is 1 - x^2 + x +4 - x 6 Etc in other words summation n + + align:start position:0% +4 - x 6 Etc in other words summation n + + + align:start position:0% +4 - x 6 Etc in other words summation n +goes from 0 to Infinity I want my signs + + align:start position:0% +goes from 0 to Infinity I want my signs + + + align:start position:0% +goes from 0 to Infinity I want my signs +to alternate with the first one being + + align:start position:0% +to alternate with the first one being + + + align:start position:0% +to alternate with the first one being +positive so I put in minus1 the n x the + + align:start position:0% +positive so I put in minus1 the n x the + + + align:start position:0% +positive so I put in minus1 the n x the +2 N and that converges for the absolute + + align:start position:0% +2 N and that converges for the absolute + + + align:start position:0% +2 N and that converges for the absolute +value of x less than one now let me just + + align:start position:0% +value of x less than one now let me just + + + align:start position:0% +value of x less than one now let me just +focus my attention on a question for you + + align:start position:0% +focus my attention on a question for you + + + align:start position:0% +focus my attention on a question for you +here and I'll come back to this I want + + align:start position:0% +here and I'll come back to this I want + + + align:start position:0% +here and I'll come back to this I want +to come back here in a second but the + + align:start position:0% +to come back here in a second but the + + + align:start position:0% +to come back here in a second but the +idea is what goes wrong when x equals + + align:start position:0% +idea is what goes wrong when x equals + + + align:start position:0% +idea is what goes wrong when x equals +plus or minus one you see let me show + + align:start position:0% +plus or minus one you see let me show + + + align:start position:0% +plus or minus one you see let me show +you what I mean by that when I saw this + + align:start position:0% +you what I mean by that when I saw this + + + align:start position:0% +you what I mean by that when I saw this +series for the first time and somebody + + align:start position:0% +series for the first time and somebody + + + align:start position:0% +series for the first time and somebody +says look at you got to be careful when + + align:start position:0% +says look at you got to be careful when + + + align:start position:0% +says look at you got to be careful when +the absolute value of U is equal to one + + align:start position:0% +the absolute value of U is equal to one + + + align:start position:0% +the absolute value of U is equal to one +that was be careful when U equals 1 or + + align:start position:0% +that was be careful when U equals 1 or + + + align:start position:0% +that was be careful when U equals 1 or +minus one well minus one didn't bother + + align:start position:0% +minus one well minus one didn't bother + + + align:start position:0% +minus one well minus one didn't bother +me that much but one I could see right + + align:start position:0% +me that much but one I could see right + + + align:start position:0% +me that much but one I could see right +away what went wrong namely When U is 1 + + align:start position:0% +away what went wrong namely When U is 1 + + + align:start position:0% +away what went wrong namely When U is 1 +here 1 over 1 minus U is 1 over Z which + + align:start position:0% +here 1 over 1 minus U is 1 over Z which + + + align:start position:0% +here 1 over 1 minus U is 1 over Z which +is undefined and I expect trouble over + + align:start position:0% +is undefined and I expect trouble over + + + align:start position:0% +is undefined and I expect trouble over +here on the other hand when the absolute + + align:start position:0% +here on the other hand when the absolute + + + align:start position:0% +here on the other hand when the absolute +value of x equals 1 here that means that + + align:start position:0% +value of x equals 1 here that means that + + + align:start position:0% +value of x equals 1 here that means that +x^2 is 1 I mean whether X is 1 or minus + + align:start position:0% +x^2 is 1 I mean whether X is 1 or minus + + + align:start position:0% +x^2 is 1 I mean whether X is 1 or minus +one x^2 is 1 look at nothing goes wrong + + align:start position:0% +one x^2 is 1 look at nothing goes wrong + + + align:start position:0% +one x^2 is 1 look at nothing goes wrong +over here 1/ 1 + x squ is perfectly well + + align:start position:0% +over here 1/ 1 + x squ is perfectly well + + + align:start position:0% +over here 1/ 1 + x squ is perfectly well +defined at the at xal 1 I would expect + + align:start position:0% +defined at the at xal 1 I would expect + + + align:start position:0% +defined at the at xal 1 I would expect +because my upbringing was such that I + + align:start position:0% +because my upbringing was such that I + + + align:start position:0% +because my upbringing was such that I +always thought that the bad points + + align:start position:0% +always thought that the bad points + + + align:start position:0% +always thought that the bad points +occurred where the denominator blew up + + align:start position:0% +occurred where the denominator blew up + + + align:start position:0% +occurred where the denominator blew up +but see this denominator never blows up + + align:start position:0% +but see this denominator never blows up + + + align:start position:0% +but see this denominator never blows up +because 1 + x^2 is always at least as + + align:start position:0% +because 1 + x^2 is always at least as + + + align:start position:0% +because 1 + x^2 is always at least as +big as + + align:start position:0% +big as + + + align:start position:0% +big as +one provided what of course that X is + + align:start position:0% +one provided what of course that X is + + + align:start position:0% +one provided what of course that X is +real because a square of a real number + + align:start position:0% +real because a square of a real number + + + align:start position:0% +real because a square of a real number +can't be negative that's the hint by the + + align:start position:0% +can't be negative that's the hint by the + + + align:start position:0% +can't be negative that's the hint by the +way the square of a complex number could + + align:start position:0% +way the square of a complex number could + + + align:start position:0% +way the square of a complex number could +certainly be negative + + align:start position:0% +certainly be negative + + + align:start position:0% +certainly be negative +and here's what I'm saying if I now take + + align:start position:0% +and here's what I'm saying if I now take + + + align:start position:0% +and here's what I'm saying if I now take +this real valued + + align:start position:0% +this real valued + + + align:start position:0% +this real valued +series and convert it to a complex + + align:start position:0% +series and convert it to a complex + + + align:start position:0% +series and convert it to a complex +valued series by replacing X by Z all + + align:start position:0% +valued series by replacing X by Z all + + + align:start position:0% +valued series by replacing X by Z all +right using the same ratio test Etc that + + align:start position:0% +right using the same ratio test Etc that + + + align:start position:0% +right using the same ratio test Etc that +we did before I can prove that this + + align:start position:0% +we did before I can prove that this + + + align:start position:0% +we did before I can prove that this +infinite Series this power series + + align:start position:0% +infinite Series this power series + + + align:start position:0% +infinite Series this power series +converges to one over 1 + z^ 2 provided + + align:start position:0% +converges to one over 1 + z^ 2 provided + + + align:start position:0% +converges to one over 1 + z^ 2 provided +the absolute value of Z is less than one + + align:start position:0% +the absolute value of Z is less than one + + + align:start position:0% +the absolute value of Z is less than one +now by the way what does it mean to say + + align:start position:0% +now by the way what does it mean to say + + + align:start position:0% +now by the way what does it mean to say +the absolute value of Z is less than one + + align:start position:0% +the absolute value of Z is less than one + + + align:start position:0% +the absolute value of Z is less than one +it means that Z is less than one unit + + align:start position:0% +it means that Z is less than one unit + + + align:start position:0% +it means that Z is less than one unit +from the origin It means that in the Aon + + align:start position:0% +from the origin It means that in the Aon + + + align:start position:0% +from the origin It means that in the Aon +diagram Z is inside the circle centered + + align:start position:0% +diagram Z is inside the circle centered + + + align:start position:0% +diagram Z is inside the circle centered +at the origin with radius equal to one + + align:start position:0% +at the origin with radius equal to one + + + align:start position:0% +at the origin with radius equal to one +but here's the key point when I look at + + align:start position:0% +but here's the key point when I look at + + + align:start position:0% +but here's the key point when I look at +this I'm not at all upset that something + + align:start position:0% +this I'm not at all upset that something + + + align:start position:0% +this I'm not at all upset that something +can go wrong on this circle namely 1 + + align:start position:0% +can go wrong on this circle namely 1 + + + align:start position:0% +can go wrong on this circle namely 1 +over 1 + z^2 factors into 1 / Z + I * Z + + align:start position:0% +over 1 + z^2 factors into 1 / Z + I * Z + + + align:start position:0% +over 1 + z^2 factors into 1 / Z + I * Z +minus I and certainly I am Leary of + + align:start position:0% +minus I and certainly I am Leary of + + + align:start position:0% +minus I and certainly I am Leary of +letting Z either equal minus I or I + + align:start position:0% +letting Z either equal minus I or I + + + align:start position:0% +letting Z either equal minus I or I +because it's going to make my + + align:start position:0% +because it's going to make my + + + align:start position:0% +because it's going to make my +denominator vanish and even in the + + align:start position:0% +denominator vanish and even in the + + + align:start position:0% +denominator vanish and even in the +complex numbers as you recall from our + + align:start position:0% +complex numbers as you recall from our + + + align:start position:0% +complex numbers as you recall from our +first lecture on complex numbers you + + align:start position:0% +first lecture on complex numbers you + + + align:start position:0% +first lecture on complex numbers you +cannot divide by zero in other words at + + align:start position:0% +cannot divide by zero in other words at + + + align:start position:0% +cannot divide by zero in other words at +a glance I recognize that Z equals plus + + align:start position:0% +a glance I recognize that Z equals plus + + + align:start position:0% +a glance I recognize that Z equals plus +or minus I is trouble in other words + + align:start position:0% +or minus I is trouble in other words + + + align:start position:0% +or minus I is trouble in other words +going to the agon diagram in this + + align:start position:0% +going to the agon diagram in this + + + align:start position:0% +going to the agon diagram in this +picture I know I'm in trouble at these + + align:start position:0% +picture I know I'm in trouble at these + + + align:start position:0% +picture I know I'm in trouble at these +two points on the circle absolute value + + align:start position:0% +two points on the circle absolute value + + + align:start position:0% +two points on the circle absolute value +of Z equals 1 remember this is a circle + + align:start position:0% +of Z equals 1 remember this is a circle + + + align:start position:0% +of Z equals 1 remember this is a circle +it's the locus of all points in the + + align:start position:0% +it's the locus of all points in the + + + align:start position:0% +it's the locus of all points in the +diagram one unit from the origin now + + align:start position:0% +diagram one unit from the origin now + + + align:start position:0% +diagram one unit from the origin now +remember what we said about the circle + + align:start position:0% +remember what we said about the circle + + + align:start position:0% +remember what we said about the circle +of convergence that that set s where the + + align:start position:0% +of convergence that that set s where the + + + align:start position:0% +of convergence that that set s where the +power series converges there is a circle + + align:start position:0% +power series converges there is a circle + + + align:start position:0% +power series converges there is a circle +such that inside the circle the thing + + align:start position:0% +such that inside the circle the thing + + + align:start position:0% +such that inside the circle the thing +always converges outside it always + + align:start position:0% +always converges outside it always + + + align:start position:0% +always converges outside it always +diverges consequently the fact that I + + align:start position:0% +diverges consequently the fact that I + + + align:start position:0% +diverges consequently the fact that I +have two bad spots over here tells me + + align:start position:0% +have two bad spots over here tells me + + + align:start position:0% +have two bad spots over here tells me +that I cannot go beyond this circle in + + align:start position:0% +that I cannot go beyond this circle in + + + align:start position:0% +that I cannot go beyond this circle in +talking about what happened with the + + align:start position:0% +talking about what happened with the + + + align:start position:0% +talking about what happened with the +power series expansion for 1 over 1+ z^2 + + align:start position:0% +power series expansion for 1 over 1+ z^2 + + + align:start position:0% +power series expansion for 1 over 1+ z^2 +notice that all I require is that + + align:start position:0% +notice that all I require is that + + + align:start position:0% +notice that all I require is that +something go wrong on the circle there + + align:start position:0% +something go wrong on the circle there + + + align:start position:0% +something go wrong on the circle there +are infinitely many points on this + + align:start position:0% +are infinitely many points on this + + + align:start position:0% +are infinitely many points on this +circle and the likelihood that the point + + align:start position:0% +circle and the likelihood that the point + + + align:start position:0% +circle and the likelihood that the point +at which things went bad happened to be + + align:start position:0% +at which things went bad happened to be + + + align:start position:0% +at which things went bad happened to be +at the point where the circle crossed + + align:start position:0% +at the point where the circle crossed + + + align:start position:0% +at the point where the circle crossed +the x-axis is particularly small in + + align:start position:0% +the x-axis is particularly small in + + + align:start position:0% +the x-axis is particularly small in +other words speaking from another point + + align:start position:0% +other words speaking from another point + + + align:start position:0% +other words speaking from another point +of view if I have the Good Fortune to be + + align:start position:0% +of view if I have the Good Fortune to be + + + align:start position:0% +of view if I have the Good Fortune to be +able to be standing in the complex + + align:start position:0% +able to be standing in the complex + + + align:start position:0% +able to be standing in the complex +number world looking down at this circle + + align:start position:0% +number world looking down at this circle + + + align:start position:0% +number world looking down at this circle +I see what went wrong if my perspective + + align:start position:0% +I see what went wrong if my perspective + + + align:start position:0% +I see what went wrong if my perspective +is limited to the xais I can't see + + align:start position:0% +is limited to the xais I can't see + + + align:start position:0% +is limited to the xais I can't see +anything that went wrong and I can't + + align:start position:0% +anything that went wrong and I can't + + + align:start position:0% +anything that went wrong and I can't +understand why I can't expand this + + align:start position:0% +understand why I can't expand this + + + align:start position:0% +understand why I can't expand this +circle further in other words the bad + + align:start position:0% +circle further in other words the bad + + + align:start position:0% +circle further in other words the bad +spots are on the magnitude of Z equals 1 + + align:start position:0% +spots are on the magnitude of Z equals 1 + + + align:start position:0% +spots are on the magnitude of Z equals 1 +but not at the point zal + + align:start position:0% +but not at the point zal + + + align:start position:0% +but not at the point zal +1 or zal minus one these were good + + align:start position:0% +1 or zal minus one these were good + + + align:start position:0% +1 or zal minus one these were good +points see these were good points these + + align:start position:0% +points see these were good points these + + + align:start position:0% +points see these were good points these +were the bad ones but all you needed was + + align:start position:0% +were the bad ones but all you needed was + + + align:start position:0% +were the bad ones but all you needed was +One Bad Apple to spoil the whole circle + + align:start position:0% +One Bad Apple to spoil the whole circle + + + align:start position:0% +One Bad Apple to spoil the whole circle +so to speak at any rate I think that's + + align:start position:0% +so to speak at any rate I think that's + + + align:start position:0% +so to speak at any rate I think that's +enough to make my point the point being + + align:start position:0% +enough to make my point the point being + + + align:start position:0% +enough to make my point the point being +that by studying complex series we do + + align:start position:0% +that by studying complex series we do + + + align:start position:0% +that by studying complex series we do +two things one is we get a larger hold + + align:start position:0% +two things one is we get a larger hold + + + align:start position:0% +two things one is we get a larger hold +on the set of analytic functions which + + align:start position:0% +on the set of analytic functions which + + + align:start position:0% +on the set of analytic functions which +help us in things like conformal + + align:start position:0% +help us in things like conformal + + + align:start position:0% +help us in things like conformal +mappings and other things which we + + align:start position:0% +mappings and other things which we + + + align:start position:0% +mappings and other things which we +haven't gone into and secondly it gives + + align:start position:0% +haven't gone into and secondly it gives + + + align:start position:0% +haven't gone into and secondly it gives +us A New Perspective at series involving + + align:start position:0% +us A New Perspective at series involving + + + align:start position:0% +us A New Perspective at series involving +real power series because we now have an + + align:start position:0% +real power series because we now have an + + + align:start position:0% +real power series because we now have an +extra Dimension from which to view the + + align:start position:0% +extra Dimension from which to view the + + + align:start position:0% +extra Dimension from which to view the +power series at any rate we'll talk + + align:start position:0% +power series at any rate we'll talk + + + align:start position:0% +power series at any rate we'll talk +about other aspects of complex variables + + align:start position:0% +about other aspects of complex variables + + + align:start position:0% +about other aspects of complex variables +namely integration next time for the + + align:start position:0% +namely integration next time for the + + + align:start position:0% +namely integration next time for the +time being do the exercises in this unit + + align:start position:0% +time being do the exercises in this unit + + + align:start position:0% +time being do the exercises in this unit +and until next time + + align:start position:0% + + + + align:start position:0% + +goodbye funding for the publication of + + align:start position:0% +goodbye funding for the publication of + + + align:start position:0% +goodbye funding for the publication of +this video was provided by the Gabriella + + align:start position:0% +this video was provided by the Gabriella + + + align:start position:0% +this video was provided by the Gabriella +and Paul rosenbom + + align:start position:0% +and Paul rosenbom + + + align:start position:0% +and Paul rosenbom +foundation help ocw continue to provide + + align:start position:0% +foundation help ocw continue to provide + + + align:start position:0% +foundation help ocw continue to provide +free and open access to MIT courses by + + align:start position:0% +free and open access to MIT courses by + + + align:start position:0% +free and open access to MIT courses by +making a donation at ocw.mit.edu/donate \ No newline at end of file diff --git a/UsGBIfjUK7U.txt b/UsGBIfjUK7U.txt new file mode 100644 index 0000000000000000000000000000000000000000..1cd4a48f73aad09ca085386aba9b01fdd8817c9c --- /dev/null +++ b/UsGBIfjUK7U.txt @@ -0,0 +1,3416 @@ +align:start position:0% + +hi welcome back to recitation you've + + align:start position:0% +hi welcome back to recitation you've + + + align:start position:0% +hi welcome back to recitation you've +been talking in class about partial + + align:start position:0% +been talking in class about partial + + + align:start position:0% +been talking in class about partial +fraction decomposition as a as a tool + + align:start position:0% +fraction decomposition as a as a tool + + + align:start position:0% +fraction decomposition as a as a tool +for integration so remember that the the + + align:start position:0% +for integration so remember that the the + + + align:start position:0% +for integration so remember that the the +point of partial fraction decomposition + + align:start position:0% +point of partial fraction decomposition + + + align:start position:0% +point of partial fraction decomposition +is that whenever you have a rational + + align:start position:0% +is that whenever you have a rational + + + align:start position:0% +is that whenever you have a rational +function that is one polinomial divided + + align:start position:0% +function that is one polinomial divided + + + align:start position:0% +function that is one polinomial divided +by another that in principle partial + + align:start position:0% +by another that in principle partial + + + align:start position:0% +by another that in principle partial +fraction decomposition lets you write + + align:start position:0% +fraction decomposition lets you write + + + align:start position:0% +fraction decomposition lets you write +any such expression as a sum of things + + align:start position:0% +any such expression as a sum of things + + + align:start position:0% +any such expression as a sum of things +Each of which is relatively easy to + + align:start position:0% +Each of which is relatively easy to + + + align:start position:0% +Each of which is relatively easy to +integrate so the the technique here is + + align:start position:0% +integrate so the the technique here is + + + align:start position:0% +integrate so the the technique here is +is purely algebraic um and then and then + + align:start position:0% +is purely algebraic um and then and then + + + align:start position:0% +is purely algebraic um and then and then +you just apply integral rules that we've + + align:start position:0% +you just apply integral rules that we've + + + align:start position:0% +you just apply integral rules that we've +already learned U so I have here four uh + + align:start position:0% +already learned U so I have here four uh + + + align:start position:0% +already learned U so I have here four uh +four rational functions for you and what + + align:start position:0% +four rational functions for you and what + + + align:start position:0% +four rational functions for you and what +I'd like you to do in each case is try + + align:start position:0% +I'd like you to do in each case is try + + + align:start position:0% +I'd like you to do in each case is try +to decompose it into the into the + + align:start position:0% +to decompose it into the into the + + + align:start position:0% +to decompose it into the into the +general form that Professor jarrison + + align:start position:0% +general form that Professor jarrison + + + align:start position:0% +general form that Professor jarrison +taught you um so don't I'm I'm not + + align:start position:0% +taught you um so don't I'm I'm not + + + align:start position:0% +taught you um so don't I'm I'm not +asking you to you know if if you like + + align:start position:0% +asking you to you know if if you like + + + align:start position:0% +asking you to you know if if you like +you're you're certainly welcome to go + + align:start position:0% +you're you're certainly welcome to go + + + align:start position:0% +you're you're certainly welcome to go +ahead and compute the the + + align:start position:0% +ahead and compute the the + + + align:start position:0% +ahead and compute the the +anti-derivatives after you do that but + + align:start position:0% +anti-derivatives after you do that but + + + align:start position:0% +anti-derivatives after you do that but +I'm not going to gonna do it for you or + + align:start position:0% +I'm not going to gonna do it for you or + + + align:start position:0% +I'm not going to gonna do it for you or +I'm I'm not gonna ask you to do it um so + + align:start position:0% +I'm I'm not gonna ask you to do it um so + + + align:start position:0% +I'm I'm not gonna ask you to do it um so +what I'd like you to do though is is is + + align:start position:0% +what I'd like you to do though is is is + + + align:start position:0% +what I'd like you to do though is is is +to for each of these four Expressions to + + align:start position:0% +to for each of these four Expressions to + + + align:start position:0% +to for each of these four Expressions to +to break it out into the into the form + + align:start position:0% +to break it out into the into the form + + + align:start position:0% +to break it out into the into the form +of the the partial fraction + + align:start position:0% +of the the partial fraction + + + align:start position:0% +of the the partial fraction +decomposition so why don't you take a + + align:start position:0% +decomposition so why don't you take a + + + align:start position:0% +decomposition so why don't you take a +few minutes to do that come back and you + + align:start position:0% +few minutes to do that come back and you + + + align:start position:0% +few minutes to do that come back and you +can check your work against + + align:start position:0% + + + + align:start position:0% + +mine all right welcome back hopefully + + align:start position:0% +mine all right welcome back hopefully + + + align:start position:0% +mine all right welcome back hopefully +you had some fun working on these uh + + align:start position:0% +you had some fun working on these uh + + + align:start position:0% +you had some fun working on these uh +they're they're a little bit tricky I + + align:start position:0% +they're they're a little bit tricky I + + + align:start position:0% +they're they're a little bit tricky I +think or I picked them to be a little + + align:start position:0% +think or I picked them to be a little + + + align:start position:0% +think or I picked them to be a little +bit tricky so let's let's go through + + align:start position:0% +bit tricky so let's let's go through + + + align:start position:0% +bit tricky so let's let's go through +them one by one I guess I'll I'll start + + align:start position:0% +them one by one I guess I'll I'll start + + + align:start position:0% +them one by one I guess I'll I'll start +with the first one + + align:start position:0% +with the first one + + + align:start position:0% +with the first one +um so for the first + + align:start position:0% +um so for the first + + + align:start position:0% +um so for the first +one I have + + align:start position:0% +one I have + + + align:start position:0% +one I have +X2 - 4x + + + align:start position:0% +X2 - 4x + + + + align:start position:0% +X2 - 4x + + + align:start position:0% + + + align:start position:0% +over x^2 - 8 x now the first thing to do + + align:start position:0% +over x^2 - 8 x now the first thing to do + + + align:start position:0% +over x^2 - 8 x now the first thing to do +when you start the partial fraction + + align:start position:0% +when you start the partial fraction + + + align:start position:0% +when you start the partial fraction +method is that you have to check that + + align:start position:0% +method is that you have to check that + + + align:start position:0% +method is that you have to check that +the degree + + align:start position:0% +the degree + + + align:start position:0% +the degree +of the numerator is smaller than the + + align:start position:0% +of the numerator is smaller than the + + + align:start position:0% +of the numerator is smaller than the +degree of the denominator now in this + + align:start position:0% +degree of the denominator now in this + + + align:start position:0% +degree of the denominator now in this +case that's not true the the it's the + + align:start position:0% +case that's not true the the it's the + + + align:start position:0% +case that's not true the the it's the +degree on top is two and the degree on + + align:start position:0% +degree on top is two and the degree on + + + align:start position:0% +degree on top is two and the degree on +bottom is two so we need to do long + + align:start position:0% +bottom is two so we need to do long + + + align:start position:0% +bottom is two so we need to do long +division or you know we need to do + + align:start position:0% +division or you know we need to do + + + align:start position:0% +division or you know we need to do +something well long division is the + + align:start position:0% +something well long division is the + + + align:start position:0% +something well long division is the +usual and and always usual way and + + align:start position:0% +usual and and always usual way and + + + align:start position:0% +usual and and always usual way and +always works in order to reduce the the + + align:start position:0% +always works in order to reduce the the + + + align:start position:0% +always works in order to reduce the the +degree of the top here so that so that + + align:start position:0% +degree of the top here so that so that + + + align:start position:0% +degree of the top here so that so that +it's smaller than the degree of the + + align:start position:0% +it's smaller than the degree of the + + + align:start position:0% +it's smaller than the degree of the +Bottom now I've I've done this ahead of + + align:start position:0% +Bottom now I've I've done this ahead of + + + align:start position:0% +Bottom now I've I've done this ahead of +time um and it's and it's not too hard + + align:start position:0% +time um and it's and it's not too hard + + + align:start position:0% +time um and it's and it's not too hard +to check that this is equal to 1 + + align:start position:0% +to check that this is equal to 1 + + + align:start position:0% +to check that this is equal to 1 ++ 4x + 4 + + align:start position:0% ++ 4x + 4 + + + align:start position:0% ++ 4x + 4 +over x^2 - 8X it's a relatively easy + + align:start position:0% +over x^2 - 8X it's a relatively easy + + + align:start position:0% +over x^2 - 8X it's a relatively easy +long division to do in any case um so + + align:start position:0% +long division to do in any case um so + + + align:start position:0% +long division to do in any case um so +okay so what we get after we do that + + align:start position:0% +okay so what we get after we do that + + + align:start position:0% +okay so what we get after we do that +process is we get something in front + + align:start position:0% +process is we get something in front + + + align:start position:0% +process is we get something in front +that's always a polom and that's good + + align:start position:0% +that's always a polom and that's good + + + align:start position:0% +that's always a polom and that's good +because remember our goal is to you know + + align:start position:0% +because remember our goal is to you know + + + align:start position:0% +because remember our goal is to you know +manipulate this into a form where we can + + align:start position:0% +manipulate this into a form where we can + + + align:start position:0% +manipulate this into a form where we can +integrate it and and polinomial are easy + + align:start position:0% +integrate it and and polinomial are easy + + + align:start position:0% +integrate it and and polinomial are easy +to integrate so then then we usually + + align:start position:0% +to integrate so then then we usually + + + align:start position:0% +to integrate so then then we usually +just forget about this for the time + + align:start position:0% +just forget about this for the time + + + align:start position:0% +just forget about this for the time +being and and what we want to do is + + align:start position:0% +being and and what we want to do is + + + align:start position:0% +being and and what we want to do is +partial fraction decompose the second + + align:start position:0% +partial fraction decompose the second + + + align:start position:0% +partial fraction decompose the second +part so to do that the first thing you + + align:start position:0% +part so to do that the first thing you + + + align:start position:0% +part so to do that the first thing you +need to do once you once you've got a + + align:start position:0% +need to do once you once you've got a + + + align:start position:0% +need to do once you once you've got a +smaller degree on top than downstairs is + + align:start position:0% +smaller degree on top than downstairs is + + + align:start position:0% +smaller degree on top than downstairs is +that you factor the the denominator so + + align:start position:0% +that you factor the the denominator so + + + align:start position:0% +that you factor the the denominator so +in this case I'm going to keep the one + + align:start position:0% +in this case I'm going to keep the one + + + align:start position:0% +in this case I'm going to keep the one +plus just so I can keep writing equals + + align:start position:0% +plus just so I can keep writing equals + + + align:start position:0% +plus just so I can keep writing equals +signs and be honest about it um but you + + align:start position:0% +signs and be honest about it um but you + + + align:start position:0% +signs and be honest about it um but you +know but but really our Focus now is + + align:start position:0% +know but but really our Focus now is + + + align:start position:0% +know but but really our Focus now is +just entirely on this on this second sum + + align:start position:0% +just entirely on this on this second sum + + + align:start position:0% +just entirely on this on this second sum +and so this is equal to 1 + + align:start position:0% +and so this is equal to 1 + + + align:start position:0% +and so this is equal to 1 ++ 4x + 4 is on top and okay so we need + + align:start position:0% ++ 4x + 4 is on top and okay so we need + + + align:start position:0% ++ 4x + 4 is on top and okay so we need +to factor the the denominator if + + align:start position:0% +to factor the the denominator if + + + align:start position:0% +to factor the the denominator if +possible and in this case that it that's + + align:start position:0% +possible and in this case that it that's + + + align:start position:0% +possible and in this case that it that's +that's not only possible it's it's + + align:start position:0% +that's not only possible it's it's + + + align:start position:0% +that's not only possible it's it's +pretty straightforward we can factor out + + align:start position:0% +pretty straightforward we can factor out + + + align:start position:0% +pretty straightforward we can factor out +an X from both terms and we see that the + + align:start position:0% +an X from both terms and we see that the + + + align:start position:0% +an X from both terms and we see that the +denominator is + + align:start position:0% +denominator is + + + align:start position:0% +denominator is +x * X whoops minus + + align:start position:0% + + + + align:start position:0% + +8 okay now in this case this is the the + + align:start position:0% +8 okay now in this case this is the the + + + align:start position:0% +8 okay now in this case this is the the +simplest situation for partial fraction + + align:start position:0% +simplest situation for partial fraction + + + align:start position:0% +simplest situation for partial fraction +decomposition we have the denominator is + + align:start position:0% +decomposition we have the denominator is + + + align:start position:0% +decomposition we have the denominator is +a product of distinct linear factors so + + align:start position:0% +a product of distinct linear factors so + + + align:start position:0% +a product of distinct linear factors so +when the denominator is a product of + + align:start position:0% +when the denominator is a product of + + + align:start position:0% +when the denominator is a product of +distinct linear factors what we get this + + align:start position:0% +distinct linear factors what we get this + + + align:start position:0% +distinct linear factors what we get this +is equal to what the partial fraction + + align:start position:0% +is equal to what the partial fraction + + + align:start position:0% +is equal to what the partial fraction +theorem tells us we can write is that + + align:start position:0% +theorem tells us we can write is that + + + align:start position:0% +theorem tells us we can write is that +this is equal + + align:start position:0% +this is equal + + + align:start position:0% +this is equal +to something some constant over the + + align:start position:0% +to something some constant over the + + + align:start position:0% +to something some constant over the +first Factor plus some constant over + + align:start position:0% +first Factor plus some constant over + + + align:start position:0% +first Factor plus some constant over +the the second Factor now if you if you + + align:start position:0% +the the second Factor now if you if you + + + align:start position:0% +the the second Factor now if you if you +had you know three factors then you + + align:start position:0% +had you know three factors then you + + + align:start position:0% +had you know three factors then you +would have three of these terms one for + + align:start position:0% +would have three of these terms one for + + + align:start position:0% +would have three of these terms one for +one for each factor if they were + + align:start position:0% +one for each factor if they were + + + align:start position:0% +one for each factor if they were +distinct linear factors so great okay + + align:start position:0% +distinct linear factors so great okay + + + align:start position:0% +distinct linear factors so great okay +now we can apply the the the coverup + + align:start position:0% +now we can apply the the the coverup + + + align:start position:0% +now we can apply the the the coverup +method that Professor jarrison taught us + + align:start position:0% +method that Professor jarrison taught us + + + align:start position:0% +method that Professor jarrison taught us +so again the one doesn't really matter + + align:start position:0% +so again the one doesn't really matter + + + align:start position:0% +so again the one doesn't really matter +here and you can just ignore it um so we + + align:start position:0% +here and you can just ignore it um so we + + + align:start position:0% +here and you can just ignore it um so we +have this is equal to this sum and we + + align:start position:0% +have this is equal to this sum and we + + + align:start position:0% +have this is equal to this sum and we +want to find the values of A and B that + + align:start position:0% +want to find the values of A and B that + + + align:start position:0% +want to find the values of A and B that +make this true and then once we have + + align:start position:0% +make this true and then once we have + + + align:start position:0% +make this true and then once we have +values of A and B that make this true + + align:start position:0% +values of A and B that make this true + + + align:start position:0% +values of A and B that make this true +the resulting expression will be all set + + align:start position:0% +the resulting expression will be all set + + + align:start position:0% +the resulting expression will be all set +to integrate right you this will just be + + align:start position:0% +to integrate right you this will just be + + + align:start position:0% +to integrate right you this will just be +easy it's just a polinomial in fact just + + align:start position:0% +easy it's just a polinomial in fact just + + + align:start position:0% +easy it's just a polinomial in fact just +a constant this is going to give us a + + align:start position:0% +a constant this is going to give us a + + + align:start position:0% +a constant this is going to give us a +logarithm and this is going to give us a + + align:start position:0% +logarithm and this is going to give us a + + + align:start position:0% +logarithm and this is going to give us a +logarithm so so once we find these + + align:start position:0% +logarithm so so once we find these + + + align:start position:0% +logarithm so so once we find these +constants A and B we're all set to + + align:start position:0% +constants A and B we're all set to + + + align:start position:0% +constants A and B we're all set to +integrate so okay so how does the cover + + align:start position:0% +integrate so okay so how does the cover + + + align:start position:0% +integrate so okay so how does the cover +up method work well so you cover + + align:start position:0% +up method work well so you cover + + + align:start position:0% +up method work well so you cover +up one of the factors in this case + + align:start position:0% +up one of the factors in this case + + + align:start position:0% +up one of the factors in this case +X and you cover up on the other side + + align:start position:0% +X and you cover up on the other side + + + align:start position:0% +X and you cover up on the other side +everything that doesn't have X in the + + align:start position:0% +everything that doesn't have X in the + + + align:start position:0% +everything that doesn't have X in the +denominator and also X and then you go + + align:start position:0% +denominator and also X and then you go + + + align:start position:0% +denominator and also X and then you go +back here and you plug in the + + align:start position:0% +back here and you plug in the + + + align:start position:0% +back here and you plug in the +appropriate value the you know the X + + align:start position:0% +appropriate value the you know the X + + + align:start position:0% +appropriate value the you know the X +minus whatever so in this case that's + + align:start position:0% +minus whatever so in this case that's + + + align:start position:0% +minus whatever so in this case that's +that's xal 0 and so over here you get 4 + + align:start position:0% +that's xal 0 and so over here you get 4 + + + align:start position:0% +that's xal 0 and so over here you get 4 +over - 8 so that gives us + + align:start position:0% +over - 8 so that gives us + + + align:start position:0% +over - 8 so that gives us +a is equal to 4 + + align:start position:0% +a is equal to 4 + + + align:start position:0% +a is equal to 4 +/ + + align:start position:0% +/ + + + align:start position:0% +/ +8 which is minus a half and now we can + + align:start position:0% +8 which is minus a half and now we can + + + align:start position:0% +8 which is minus a half and now we can +do the same thing with the x - 8 part so + + align:start position:0% +do the same thing with the x - 8 part so + + + align:start position:0% +do the same thing with the x - 8 part so +we cover up x - 8 we cover up everything + + align:start position:0% +we cover up x - 8 we cover up everything + + + align:start position:0% +we cover up x - 8 we cover up everything +that doesn't have an x - 8 in it so + + align:start position:0% +that doesn't have an x - 8 in it so + + + align:start position:0% +that doesn't have an x - 8 in it so +we've got on the right hand side we get + + align:start position:0% +we've got on the right hand side we get + + + align:start position:0% +we've got on the right hand side we get +B and on the left hand side we have have + + align:start position:0% +B and on the left hand side we have have + + + align:start position:0% +B and on the left hand side we have have +to plug in 8 here so we plug 4 * 8 + 4 + + align:start position:0% +to plug in 8 here so we plug 4 * 8 + 4 + + + align:start position:0% +to plug in 8 here so we plug 4 * 8 + 4 +which is 32 is 36 and divided by 8 so + + align:start position:0% +which is 32 is 36 and divided by 8 so + + + align:start position:0% +which is 32 is 36 and divided by 8 so +that's 36 divided 8 is 9 / + + align:start position:0% + + + + align:start position:0% + +2 so once you've got these values of A + + align:start position:0% +2 so once you've got these values of A + + + align:start position:0% +2 so once you've got these values of A +and B okay so so so our original + + align:start position:0% +and B okay so so so our original + + + align:start position:0% +and B okay so so so our original +expression now we substitute in these + + align:start position:0% +expression now we substitute in these + + + align:start position:0% +expression now we substitute in these +values of A and B then we know that this + + align:start position:0% +values of A and B then we know that this + + + align:start position:0% +values of A and B then we know that this +is a true equality and then the + + align:start position:0% +is a true equality and then the + + + align:start position:0% +is a true equality and then the +integration of this expression is just + + align:start position:0% +integration of this expression is just + + + align:start position:0% +integration of this expression is just +reduced completely to the integration of + + align:start position:0% +reduced completely to the integration of + + + align:start position:0% +reduced completely to the integration of +this easy to integrate expression okay + + align:start position:0% +this easy to integrate expression okay + + + align:start position:0% +this easy to integrate expression okay +and so this is the partial fraction + + align:start position:0% +and so this is the partial fraction + + + align:start position:0% +and so this is the partial fraction +decomposition here with with you know + + align:start position:0% +decomposition here with with you know + + + align:start position:0% +decomposition here with with you know +with a equals minus a half and b equals + + align:start position:0% +with a equals minus a half and b equals + + + align:start position:0% +with a equals minus a half and b equals +9 halfes so that's part A let's go on to + + align:start position:0% +9 halfes so that's part A let's go on to + + + align:start position:0% +9 halfes so that's part A let's go on to +Part + + align:start position:0% +Part + + + align:start position:0% +Part +B I have to remind myself what part B is + + align:start position:0% +B I have to remind myself what part B is + + + align:start position:0% +B I have to remind myself what part B is +ah okay so Part B is x^2 / x + 1 4th + + align:start position:0% + + + + align:start position:0% + +so in this case in the denominator we + + align:start position:0% +so in this case in the denominator we + + + align:start position:0% +so in this case in the denominator we +still have only linear factors but we + + align:start position:0% +still have only linear factors but we + + + align:start position:0% +still have only linear factors but we +have repeated factors and I mean this + + align:start position:0% +have repeated factors and I mean this + + + align:start position:0% +have repeated factors and I mean this +this is actually a particularly simple + + align:start position:0% +this is actually a particularly simple + + + align:start position:0% +this is actually a particularly simple +example where we have only one factor + + align:start position:0% +example where we have only one factor + + + align:start position:0% +example where we have only one factor +but it's repeated four times right + + align:start position:0% +but it's repeated four times right + + + align:start position:0% +but it's repeated four times right +fourth power so when you have that + + align:start position:0% +fourth power so when you have that + + + align:start position:0% +fourth power so when you have that +situation the partial fraction + + align:start position:0% +situation the partial fraction + + + align:start position:0% +situation the partial fraction +decomposition looks a little bit + + align:start position:0% +decomposition looks a little bit + + + align:start position:0% +decomposition looks a little bit +different and so what you get is that + + align:start position:0% +different and so what you get is that + + + align:start position:0% +different and so what you get is that +you have for every repeated power + + align:start position:0% +you have for every repeated power + + + align:start position:0% +you have for every repeated power +so for each this this one appears four + + align:start position:0% +so for each this this one appears four + + + align:start position:0% +so for each this this one appears four +times so you get four sum ANS on the + + align:start position:0% +times so you get four sum ANS on the + + + align:start position:0% +times so you get four sum ANS on the +right hand side with increasing powers + + align:start position:0% +right hand side with increasing powers + + + align:start position:0% +right hand side with increasing powers +of of this this linear Factor so with + + align:start position:0% +of of this this linear Factor so with + + + align:start position:0% +of of this this linear Factor so with +increasing powers of xus one so this is + + align:start position:0% +increasing powers of xus one so this is + + + align:start position:0% +increasing powers of xus one so this is +going to be a or sorry x + 1 um a over x + + align:start position:0% +going to be a or sorry x + 1 um a over x + + + align:start position:0% +going to be a or sorry x + 1 um a over x ++ 1 plus b over x + 1 + + align:start position:0% ++ 1 plus b over x + 1 + + + align:start position:0% ++ 1 plus b over x + 1 +squared plus + + align:start position:0% +squared plus + + + align:start position:0% +squared plus +C over x + 1 cubed plus + + align:start position:0% +C over x + 1 cubed plus + + + align:start position:0% +C over x + 1 cubed plus +d over x + 1 to the 4th now remember + + align:start position:0% +d over x + 1 to the 4th now remember + + + align:start position:0% +d over x + 1 to the 4th now remember +even though the degree here goes up in + + align:start position:0% +even though the degree here goes up in + + + align:start position:0% +even though the degree here goes up in +these in these later sums what stays on + + align:start position:0% +these in these later sums what stays on + + + align:start position:0% +these in these later sums what stays on +top is is the same it's it just stays a + + align:start position:0% +top is is the same it's it just stays a + + + align:start position:0% +top is is the same it's it just stays a +constant If This Were a quadratic Factor + + align:start position:0% +constant If This Were a quadratic Factor + + + align:start position:0% +constant If This Were a quadratic Factor +it would it would stay linear it doesn't + + align:start position:0% +it would it would stay linear it doesn't + + + align:start position:0% +it would it would stay linear it doesn't +it the top doesn't increase in degree + + align:start position:0% +it the top doesn't increase in degree + + + align:start position:0% +it the top doesn't increase in degree +when you do this um and a good a good + + align:start position:0% +when you do this um and a good a good + + + align:start position:0% +when you do this um and a good a good +simple way to check that you've you've + + align:start position:0% +simple way to check that you've you've + + + align:start position:0% +simple way to check that you've you've +got the right AB you know before you + + align:start position:0% +got the right AB you know before you + + + align:start position:0% +got the right AB you know before you +solve for the constant make sure you've + + align:start position:0% +solve for the constant make sure you've + + + align:start position:0% +solve for the constant make sure you've +got the right abstract decomposition is + + align:start position:0% +got the right abstract decomposition is + + + align:start position:0% +got the right abstract decomposition is +is to count the number of of these these + + align:start position:0% +is to count the number of of these these + + + align:start position:0% +is to count the number of of these these +constants that you're looking for it + + align:start position:0% +constants that you're looking for it + + + align:start position:0% +constants that you're looking for it +should be it should always match the the + + align:start position:0% +should be it should always match the the + + + align:start position:0% +should be it should always match the the +degree of the denominator over here so + + align:start position:0% +degree of the denominator over here so + + + align:start position:0% +degree of the denominator over here so +in this case the degree of the + + align:start position:0% +in this case the degree of the + + + align:start position:0% +in this case the degree of the +denominator is four and there are four + + align:start position:0% +denominator is four and there are four + + + align:start position:0% +denominator is four and there are four +constants so we've so so so that's a + + align:start position:0% +constants so we've so so so that's a + + + align:start position:0% +constants so we've so so so that's a +good way to check that that you set the + + align:start position:0% +good way to check that that you set the + + + align:start position:0% +good way to check that that you set the +problem up right okay so now um what do + + align:start position:0% +problem up right okay so now um what do + + + align:start position:0% +problem up right okay so now um what do +we do in this case well the coverup + + align:start position:0% +we do in this case well the coverup + + + align:start position:0% +we do in this case well the coverup +method works but it only works to find + + align:start position:0% +method works but it only works to find + + + align:start position:0% +method works but it only works to find +the the highest degree term right so we + + align:start position:0% +the the highest degree term right so we + + + align:start position:0% +the the highest degree term right so we +cover up x + 1 4th and we cover up + + align:start position:0% +cover up x + 1 4th and we cover up + + + align:start position:0% +cover up x + 1 4th and we cover up +everything with a smaller power of X+ + + align:start position:0% +everything with a smaller power of X+ + + + align:start position:0% +everything with a smaller power of X+ +one and then we plug in uh negative 1 + + align:start position:0% +one and then we plug in uh negative 1 + + + align:start position:0% +one and then we plug in uh negative 1 +right because we need X plus one to be + + align:start position:0% +right because we need X plus one to be + + + align:start position:0% +right because we need X plus one to be +to be zero so okay so over here we get + + align:start position:0% +to be zero so okay so over here we get + + + align:start position:0% +to be zero so okay so over here we get +netive 1^2 is 1 so we get right away + + align:start position:0% +netive 1^2 is 1 so we get right away + + + align:start position:0% +netive 1^2 is 1 so we get right away +that D is equal to + + align:start position:0% + + + + align:start position:0% + +one okay but that doesn't give us a b or + + align:start position:0% +one okay but that doesn't give us a b or + + + align:start position:0% +one okay but that doesn't give us a b or +c we can't get a b or c by the coverup + + align:start position:0% +c we can't get a b or c by the coverup + + + align:start position:0% +c we can't get a b or c by the coverup +method now there are couple different + + align:start position:0% +method now there are couple different + + + align:start position:0% +method now there are couple different +ways you can proceed at this + + align:start position:0% +ways you can proceed at this + + + align:start position:0% +ways you can proceed at this +point one thing you can do which is + + align:start position:0% +point one thing you can do which is + + + align:start position:0% +point one thing you can do which is +something that often Works um is you + + align:start position:0% +something that often Works um is you + + + align:start position:0% +something that often Works um is you +could uh plug in values well so this + + align:start position:0% +could uh plug in values well so this + + + align:start position:0% +could uh plug in values well so this +will always work I shouldn't say often + + align:start position:0% +will always work I shouldn't say often + + + align:start position:0% +will always work I shouldn't say often +works you can start plugging in other + + align:start position:0% +works you can start plugging in other + + + align:start position:0% +works you can start plugging in other +values for x and as you plug in other + + align:start position:0% +values for x and as you plug in other + + + align:start position:0% +values for x and as you plug in other +values for X what you'll see is that for + + align:start position:0% +values for X what you'll see is that for + + + align:start position:0% +values for X what you'll see is that for +every value you plug in you'll get a + + align:start position:0% +every value you plug in you'll get a + + + align:start position:0% +every value you plug in you'll get a +linear equation + + align:start position:0% +linear equation + + + align:start position:0% +linear equation +relating your variables a b c and + + align:start position:0% +relating your variables a b c and + + + align:start position:0% +relating your variables a b c and +whatever in this case that's all we've + + align:start position:0% +whatever in this case that's all we've + + + align:start position:0% +whatever in this case that's all we've +got left a b and c to each other and so + + align:start position:0% +got left a b and c to each other and so + + + align:start position:0% +got left a b and c to each other and so +if you plug in three different values of + + align:start position:0% +if you plug in three different values of + + + align:start position:0% +if you plug in three different values of +X say you'll get three different linear + + align:start position:0% +X say you'll get three different linear + + + align:start position:0% +X say you'll get three different linear +equations with three different variables + + align:start position:0% +equations with three different variables + + + align:start position:0% +equations with three different variables +and then you can solve them that's one + + align:start position:0% +and then you can solve them that's one + + + align:start position:0% +and then you can solve them that's one +thing you can do another thing you could + + align:start position:0% +thing you can do another thing you could + + + align:start position:0% +thing you can do another thing you could +do is you can multiply through by x + 1 + + align:start position:0% +do is you can multiply through by x + 1 + + + align:start position:0% +do is you can multiply through by x + 1 +4th so if you do that you'll have on the + + align:start position:0% +4th so if you do that you'll have on the + + + align:start position:0% +4th so if you do that you'll have on the +left you'll just have X squ and on the + + align:start position:0% +left you'll just have X squ and on the + + + align:start position:0% +left you'll just have X squ and on the +right you'll have well you have a * x + + + align:start position:0% +right you'll have well you have a * x + + + + align:start position:0% +right you'll have well you have a * x + +1 cubed plus b * x + 1^ 2 plus C * X+ 1 + + align:start position:0% +1 cubed plus b * x + 1^ 2 plus C * X+ 1 + + + align:start position:0% +1 cubed plus b * x + 1^ 2 plus C * X+ 1 +plus d and we already know that D is + + align:start position:0% +plus d and we already know that D is + + + align:start position:0% +plus d and we already know that D is +equal to one okay and so then for those + + align:start position:0% +equal to one okay and so then for those + + + align:start position:0% +equal to one okay and so then for those +two things to be equal they're equal as + + align:start position:0% +two things to be equal they're equal as + + + align:start position:0% +two things to be equal they're equal as +pols all their coefficients have to be + + align:start position:0% +pols all their coefficients have to be + + + align:start position:0% +pols all their coefficients have to be +equal so you can just look at the + + align:start position:0% +equal so you can just look at the + + + align:start position:0% +equal so you can just look at the +coefficients in that resulting + + align:start position:0% +coefficients in that resulting + + + align:start position:0% +coefficients in that resulting +expression and ask um you know which + + align:start position:0% +expression and ask um you know which + + + align:start position:0% +expression and ask um you know which +which + + align:start position:0% +which + + + align:start position:0% +which +coefficients uh sorry and you can you + + align:start position:0% +coefficients uh sorry and you can you + + + align:start position:0% +coefficients uh sorry and you can you +can set coefficients on the two sides + + align:start position:0% +can set coefficients on the two sides + + + align:start position:0% +can set coefficients on the two sides +equal if the two Pol are equal all their + + align:start position:0% +equal if the two Pol are equal all their + + + align:start position:0% +equal if the two Pol are equal all their +corresponding coefficients are equal so + + align:start position:0% +corresponding coefficients are equal so + + + align:start position:0% +corresponding coefficients are equal so +you could look you know at this side and + + align:start position:0% +you could look you know at this side and + + + align:start position:0% +you could look you know at this side and +you'll say oh okay so the coefficient of + + align:start position:0% +you'll say oh okay so the coefficient of + + + align:start position:0% +you'll say oh okay so the coefficient of +x cubed has to be the same as whatever + + align:start position:0% +x cubed has to be the same as whatever + + + align:start position:0% +x cubed has to be the same as whatever +the coefficient of x cubed over here is + + align:start position:0% +the coefficient of x cubed over here is + + + align:start position:0% +the coefficient of x cubed over here is +and the coefficient of x squ has to be + + align:start position:0% +and the coefficient of x squ has to be + + + align:start position:0% +and the coefficient of x squ has to be +the same as the coefficient of x squ and + + align:start position:0% +the same as the coefficient of x squ and + + + align:start position:0% +the same as the coefficient of x squ and +and so on so that's another way to + + align:start position:0% +and so on so that's another way to + + + align:start position:0% +and so on so that's another way to +proceed um + + align:start position:0% + + + + align:start position:0% + +a yeah all right th those are really + + align:start position:0% +a yeah all right th those are really + + + align:start position:0% +a yeah all right th those are really +your your two your two best options um I + + align:start position:0% +your your two your two best options um I + + + align:start position:0% +your your two your two best options um I +like I like to multiply through + + align:start position:0% +like I like to multiply through + + + align:start position:0% +like I like to multiply through +personally um so okay so so if I were to + + align:start position:0% +personally um so okay so so if I were to + + + align:start position:0% +personally um so okay so so if I were to +do that in this case on the left hand + + align:start position:0% +do that in this case on the left hand + + + align:start position:0% +do that in this case on the left hand +side I'd get x^2 = a * x + 1 cubed + B * + + align:start position:0% +side I'd get x^2 = a * x + 1 cubed + B * + + + align:start position:0% +side I'd get x^2 = a * x + 1 cubed + B * +x + 1 + + align:start position:0% +x + 1 + + + align:start position:0% +x + 1 +2 + + + align:start position:0% +2 + + + + align:start position:0% +2 + +C * x + 1 plus d except we already know + + align:start position:0% +C * x + 1 plus d except we already know + + + align:start position:0% +C * x + 1 plus d except we already know +that D is equal to one so I'm just going + + align:start position:0% +that D is equal to one so I'm just going + + + align:start position:0% +that D is equal to one so I'm just going +to write + one + + align:start position:0% + + + + align:start position:0% + +so okay so actually let me let me say + + align:start position:0% +so okay so actually let me let me say + + + align:start position:0% +so okay so actually let me let me say +that there there are other things you + + align:start position:0% +that there there are other things you + + + align:start position:0% +that there there are other things you +could do which is you could you could + + align:start position:0% +could do which is you could you could + + + align:start position:0% +could do which is you could you could +rearrange things and and simplify + + align:start position:0% +rearrange things and and simplify + + + align:start position:0% +rearrange things and and simplify +algebraically before plugging in values + + align:start position:0% +algebraically before plugging in values + + + align:start position:0% +algebraically before plugging in values +or before comparing coefficients um so + + align:start position:0% +or before comparing coefficients um so + + + align:start position:0% +or before comparing coefficients um so +let me give you one example of of each + + align:start position:0% +let me give you one example of of each + + + align:start position:0% +let me give you one example of of each +of those three possibilities so for + + align:start position:0% +of those three possibilities so for + + + align:start position:0% +of those three possibilities so for +example um one thing you can do is you + + align:start position:0% +example um one thing you can do is you + + + align:start position:0% +example um one thing you can do is you +can look at look at the highest degree + + align:start position:0% +can look at look at the highest degree + + + align:start position:0% +can look at look at the highest degree +coefficient so as professor jarrison + + align:start position:0% +coefficient so as professor jarrison + + + align:start position:0% +coefficient so as professor jarrison +said the easiest coefficients are + + align:start position:0% +said the easiest coefficients are + + + align:start position:0% +said the easiest coefficients are +usually the high order terms and and the + + align:start position:0% +usually the high order terms and and the + + + align:start position:0% +usually the high order terms and and the +low order terms so in this case the high + + align:start position:0% +low order terms so in this case the high + + + align:start position:0% +low order terms so in this case the high +order term would be that this is a third + + align:start position:0% +order term would be that this is a third + + + align:start position:0% +order term would be that this is a third +degree polinomial on the right hand side + + align:start position:0% +degree polinomial on the right hand side + + + align:start position:0% +degree polinomial on the right hand side +and it's a second degree polinomial on + + align:start position:0% +and it's a second degree polinomial on + + + align:start position:0% +and it's a second degree polinomial on +the left um so the the the highest order + + align:start position:0% +the left um so the the the highest order + + + align:start position:0% +the left um so the the the highest order +term here x cubed it just appears in + + align:start position:0% +term here x cubed it just appears in + + + align:start position:0% +term here x cubed it just appears in +this one place as coefficient a right + + align:start position:0% +this one place as coefficient a right + + + align:start position:0% +this one place as coefficient a right +this is ax cubed plus something time x s + + align:start position:0% +this is ax cubed plus something time x s + + + align:start position:0% +this is ax cubed plus something time x s +plus blah blah blah blah blah and over + + align:start position:0% +plus blah blah blah blah blah and over + + + align:start position:0% +plus blah blah blah blah blah and over +here we have no X + + align:start position:0% +here we have no X + + + align:start position:0% +here we have no X +cubes so you have X cubes here but no X + + align:start position:0% +cubes so you have X cubes here but no X + + + align:start position:0% +cubes so you have X cubes here but no X +cubes here that means the coefficient of + + align:start position:0% +cubes here that means the coefficient of + + + align:start position:0% +cubes here that means the coefficient of +x Cub here has to be zero so a has to be + + align:start position:0% +x Cub here has to be zero so a has to be + + + align:start position:0% +x Cub here has to be zero so a has to be +zero + + align:start position:0% + + + + align:start position:0% + +okay so a has to be equal to zero and + + align:start position:0% +okay so a has to be equal to zero and + + + align:start position:0% +okay so a has to be equal to zero and +that simplifies everything a little bit + + align:start position:0% +that simplifies everything a little bit + + + align:start position:0% +that simplifies everything a little bit +so now we get x^2 equal B * x + 1 2 + C + + align:start position:0% +so now we get x^2 equal B * x + 1 2 + C + + + align:start position:0% +so now we get x^2 equal B * x + 1 2 + C +* x + + + align:start position:0% +* x + + + + align:start position:0% +* x + +1 plus + + align:start position:0% +1 plus + + + align:start position:0% +1 plus +one now let me show you what I mean + + align:start position:0% +one now let me show you what I mean + + + align:start position:0% +one now let me show you what I mean +about + + align:start position:0% +about + + + align:start position:0% +about +algebraic uh manipulation this one if + + align:start position:0% +algebraic uh manipulation this one if + + + align:start position:0% +algebraic uh manipulation this one if +you wanted you could you could always + + align:start position:0% +you wanted you could you could always + + + align:start position:0% +you wanted you could you could always +just subtract it over to the other side + + align:start position:0% +just subtract it over to the other side + + + align:start position:0% +just subtract it over to the other side +right and so then you'll have on the + + align:start position:0% +right and so then you'll have on the + + + align:start position:0% +right and so then you'll have on the +left you'll have x^2 - 1 and x^2 - 1 you + + align:start position:0% +left you'll have x^2 - 1 and x^2 - 1 you + + + align:start position:0% +left you'll have x^2 - 1 and x^2 - 1 you +can write as x -1 * x + 1 + + align:start position:0% +can write as x -1 * x + 1 + + + align:start position:0% +can write as x -1 * x + 1 += B * x + 1^ 2 + C + + align:start position:0% += B * x + 1^ 2 + C + + + align:start position:0% += B * x + 1^ 2 + C +* x + one and now you could divide out + + align:start position:0% +* x + one and now you could divide out + + + align:start position:0% +* x + one and now you could divide out +by an X plus one everywhere it appears + + align:start position:0% +by an X plus one everywhere it appears + + + align:start position:0% +by an X plus one everywhere it appears +in all terms so you get x -1 = B * x + + + align:start position:0% +in all terms so you get x -1 = B * x + + + + align:start position:0% +in all terms so you get x -1 = B * x + +1 plus c + + align:start position:0% +1 plus c + + + align:start position:0% +1 plus c +and now what this does for you is is you + + align:start position:0% +and now what this does for you is is you + + + align:start position:0% +and now what this does for you is is you +sort of just reduced the degree + + align:start position:0% +sort of just reduced the degree + + + align:start position:0% +sort of just reduced the degree +everywhere and actually you you could + + align:start position:0% +everywhere and actually you you could + + + align:start position:0% +everywhere and actually you you could +you could substitute xals minus one + + align:start position:0% +you could substitute xals minus one + + + align:start position:0% +you could substitute xals minus one +again if you wanted to for example um + + align:start position:0% +again if you wanted to for example um + + + align:start position:0% +again if you wanted to for example um +and here so for example if you + + align:start position:0% +and here so for example if you + + + align:start position:0% +and here so for example if you +substitute xal minus one this that's + + align:start position:0% +substitute xal minus one this that's + + + align:start position:0% +substitute xal minus one this that's +that's the same as it's the same idea as + + align:start position:0% +that's the same as it's the same idea as + + + align:start position:0% +that's the same as it's the same idea as +what you do in the coverup method um + + align:start position:0% +what you do in the coverup method um + + + align:start position:0% +what you do in the coverup method um +this this B term will just die + + align:start position:0% +this this B term will just die + + + align:start position:0% +this this B term will just die +completely and you'll be left with + + align:start position:0% +completely and you'll be left with + + + align:start position:0% +completely and you'll be left with +negative -2 on the left so you get C I'm + + align:start position:0% +negative -2 on the left so you get C I'm + + + align:start position:0% +negative -2 on the left so you get C I'm +going to have to move over here sorry so + + align:start position:0% +going to have to move over here sorry so + + + align:start position:0% +going to have to move over here sorry so +C is equal to -2 then and also you can + + align:start position:0% +C is equal to -2 then and also you can + + + align:start position:0% +C is equal to -2 then and also you can +do the the the one thing I haven't done + + align:start position:0% +do the the the one thing I haven't done + + + align:start position:0% +do the the the one thing I haven't done +so far is this plugging in nice choices + + align:start position:0% +so far is this plugging in nice choices + + + align:start position:0% +so far is this plugging in nice choices +of values so another nice choice of + + align:start position:0% +of values so another nice choice of + + + align:start position:0% +of values so another nice choice of +value for x that we haven't used is xals + + align:start position:0% +value for x that we haven't used is xals + + + align:start position:0% +value for x that we haven't used is xals +0 so if you plug in xal 0 you get minus1 + + align:start position:0% +0 so if you plug in xal 0 you get minus1 + + + align:start position:0% +0 so if you plug in xal 0 you get minus1 += b + C so -1 = b + C and since we just + + align:start position:0% += b + C so -1 = b + C and since we just + + + align:start position:0% += b + C so -1 = b + C and since we just +found C that means that b is equal to + + align:start position:0% +found C that means that b is equal to + + + align:start position:0% +found C that means that b is equal to +1 all right + + align:start position:0% +1 all right + + + align:start position:0% +1 all right +so oh boy I'm using a lot of space + + align:start position:0% +so oh boy I'm using a lot of space + + + align:start position:0% +so oh boy I'm using a lot of space +aren't I all right right so in this case + + align:start position:0% +aren't I all right right so in this case + + + align:start position:0% +aren't I all right right so in this case +we've got our coefficients AAL 0 d = 1 + + align:start position:0% +we've got our coefficients AAL 0 d = 1 + + + align:start position:0% +we've got our coefficients AAL 0 d = 1 +Bal 1 Cal min-2 and that gives us the + + align:start position:0% +Bal 1 Cal min-2 and that gives us the + + + align:start position:0% +Bal 1 Cal min-2 and that gives us the +partial fraction + + align:start position:0% +partial fraction + + + align:start position:0% +partial fraction +decomposition um let's go back over here + + align:start position:0% +decomposition um let's go back over here + + + align:start position:0% +decomposition um let's go back over here +then and and look at question C so for C + + align:start position:0% +then and and look at question C so for C + + + align:start position:0% +then and and look at question C so for C +the question is what is the partial + + align:start position:0% +the question is what is the partial + + + align:start position:0% +the question is what is the partial +fraction decomposition of 2x + 2 divided + + align:start position:0% +fraction decomposition of 2x + 2 divided + + + align:start position:0% +fraction decomposition of 2x + 2 divided +the quantity 4x^2 + 1^ + + align:start position:0% +the quantity 4x^2 + 1^ + + + align:start position:0% +the quantity 4x^2 + 1^ +2 uh this one's really easy this one is + + align:start position:0% +2 uh this one's really easy this one is + + + align:start position:0% +2 uh this one's really easy this one is +n this is already partial fraction + + align:start position:0% +n this is already partial fraction + + + align:start position:0% +n this is already partial fraction +decomposed right when you when you when + + align:start position:0% +decomposed right when you when you when + + + align:start position:0% +decomposed right when you when you when +you have so so here we have an + + align:start position:0% +you have so so here we have an + + + align:start position:0% +you have so so here we have an +irreducible quadratic in the denominator + + align:start position:0% +irreducible quadratic in the denominator + + + align:start position:0% +irreducible quadratic in the denominator +you can't you can't Factor this any + + align:start position:0% +you can't you can't Factor this any + + + align:start position:0% +you can't you can't Factor this any +further than it's than it's gone it it + + align:start position:0% +further than it's than it's gone it it + + + align:start position:0% +further than it's than it's gone it it +also occurs to to a higher power so when + + align:start position:0% +also occurs to to a higher power so when + + + align:start position:0% +also occurs to to a higher power so when +you when you partial fraction decompose + + align:start position:0% +you when you partial fraction decompose + + + align:start position:0% +you when you partial fraction decompose +something like this you want something + + align:start position:0% +something like this you want something + + + align:start position:0% +something like this you want something +linear over 4x^2 + 1 plus something + + align:start position:0% +linear over 4x^2 + 1 plus something + + + align:start position:0% +linear over 4x^2 + 1 plus something +linear over 4x^2 + 1^ + + align:start position:0% +linear over 4x^2 + 1^ + + + align:start position:0% +linear over 4x^2 + 1^ +2 but we already have that right the the + + align:start position:0% +2 but we already have that right the the + + + align:start position:0% +2 but we already have that right the the +the the first linear part is zero and + + align:start position:0% +the the first linear part is zero and + + + align:start position:0% +the the first linear part is zero and +the second is is something linear over + + align:start position:0% +the second is is something linear over + + + align:start position:0% +the second is is something linear over +4x^2 + 1^2 so to integrate this it's + + align:start position:0% +4x^2 + 1^2 so to integrate this it's + + + align:start position:0% +4x^2 + 1^2 so to integrate this it's +already in a pretty good form now you're + + align:start position:0% +already in a pretty good form now you're + + + align:start position:0% +already in a pretty good form now you're +actually going to right if you wanted to + + align:start position:0% +actually going to right if you wanted to + + + align:start position:0% +actually going to right if you wanted to +integrate this you would you would split + + align:start position:0% +integrate this you would you would split + + + align:start position:0% +integrate this you would you would split +it into into two pieces one with the 2X + + align:start position:0% +it into into two pieces one with the 2X + + + align:start position:0% +it into into two pieces one with the 2X +and then one with the two and the first + + align:start position:0% +and then one with the two and the first + + + align:start position:0% +and then one with the two and the first +one you would just be a usual U + + align:start position:0% +one you would just be a usual U + + + align:start position:0% +one you would just be a usual U +substitution and the second one you + + align:start position:0% +substitution and the second one you + + + align:start position:0% +substitution and the second one you +would want some sort of trigonometric + + align:start position:0% +would want some sort of trigonometric + + + align:start position:0% +would want some sort of trigonometric +substitution um but but it but this one + + align:start position:0% +substitution um but but it but this one + + + align:start position:0% +substitution um but but it but this one +is already ready for for methods where + + align:start position:0% +is already ready for for methods where + + + align:start position:0% +is already ready for for methods where +already should be comfortable with okay + + align:start position:0% +already should be comfortable with okay + + + align:start position:0% +already should be comfortable with okay +so see that's that's easy it's done + + align:start position:0% +so see that's that's easy it's done + + + align:start position:0% +so see that's that's easy it's done +already I'll put a check mark there + + align:start position:0% +already I'll put a check mark there + + + align:start position:0% +already I'll put a check mark there +because that makes me happy okay and so + + align:start position:0% +because that makes me happy okay and so + + + align:start position:0% +because that makes me happy okay and so +for the all right for this last one um + + align:start position:0% +for the all right for this last one um + + + align:start position:0% +for the all right for this last one um +I'm I'm also not going to write this one + + align:start position:0% +I'm I'm also not going to write this one + + + align:start position:0% +I'm I'm also not going to write this one +out uh but the thing to notice here is + + align:start position:0% +out uh but the thing to notice here is + + + align:start position:0% +out uh but the thing to notice here is +that the way I wrote it this was really + + align:start position:0% +that the way I wrote it this was really + + + align:start position:0% +that the way I wrote it this was really +mean of me right I wrote it as x^2 minus + + align:start position:0% +mean of me right I wrote it as x^2 minus + + + align:start position:0% +mean of me right I wrote it as x^2 minus +1^ s so a natural instinct is say aha + + align:start position:0% +1^ s so a natural instinct is say aha + + + align:start position:0% +1^ s so a natural instinct is say aha +it's a quadratic repeated factor in the + + align:start position:0% +it's a quadratic repeated factor in the + + + align:start position:0% +it's a quadratic repeated factor in the +denominator right but but that but + + align:start position:0% +denominator right but but that but + + + align:start position:0% +denominator right but but that but +that's just because I was mean and I + + align:start position:0% +that's just because I was mean and I + + + align:start position:0% +that's just because I was mean and I +wrote it this way that's not actually + + align:start position:0% +wrote it this way that's not actually + + + align:start position:0% +wrote it this way that's not actually +what this is this this is not + + align:start position:0% +what this is this this is not + + + align:start position:0% +what this is this this is not +irreducible this factors you can + + align:start position:0% +irreducible this factors you can + + + align:start position:0% +irreducible this factors you can +rewrite let me let me come back over + + align:start position:0% +rewrite let me let me come back over + + + align:start position:0% +rewrite let me let me come back over +here so this is for question D so you + + align:start position:0% +here so this is for question D so you + + + align:start position:0% +here so this is for question D so you +can rewrite x^2 - one squared as x -1 2 + + align:start position:0% +can rewrite x^2 - one squared as x -1 2 + + + align:start position:0% +can rewrite x^2 - one squared as x -1 2 +* x + 1 squar you can you can Factor + + align:start position:0% +* x + 1 squar you can you can Factor + + + align:start position:0% +* x + 1 squar you can you can Factor +this x^2 - + + align:start position:0% +this x^2 - + + + align:start position:0% +this x^2 - +one um so when you factor this x -1 what + + align:start position:0% +one um so when you factor this x -1 what + + + align:start position:0% +one um so when you factor this x -1 what +you see is this isn't a problem that has + + align:start position:0% +you see is this isn't a problem that has + + + align:start position:0% +you see is this isn't a problem that has +one irreducible quadratic Factor + + align:start position:0% +one irreducible quadratic Factor + + + align:start position:0% +one irreducible quadratic Factor +appearing to the second power what it + + align:start position:0% +appearing to the second power what it + + + align:start position:0% +appearing to the second power what it +has is two linear factors each appearing + + align:start position:0% +has is two linear factors each appearing + + + align:start position:0% +has is two linear factors each appearing +to the second power so the partial + + align:start position:0% +to the second power so the partial + + + align:start position:0% +to the second power so the partial +fraction decomposition in this problem + + align:start position:0% +fraction decomposition in this problem + + + align:start position:0% +fraction decomposition in this problem +will be something like a over x + + align:start position:0% +will be something like a over x + + + align:start position:0% +will be something like a over x +-1 + B over x -1 2ar + C over x + 1 plus + + align:start position:0% +-1 + B over x -1 2ar + C over x + 1 plus + + + align:start position:0% +-1 + B over x -1 2ar + C over x + 1 plus +D + + align:start position:0% +D + + + align:start position:0% +D +over x + 1 + + align:start position:0% +over x + 1 + + + align:start position:0% +over x + 1 +2 that's what we you'll get when you + + align:start position:0% +2 that's what we you'll get when you + + + align:start position:0% +2 that's what we you'll get when you +when you apply partial fraction + + align:start position:0% +when you apply partial fraction + + + align:start position:0% +when you apply partial fraction +decomposition to this problem and then + + align:start position:0% +decomposition to this problem and then + + + align:start position:0% +decomposition to this problem and then +you have to solve for the for the + + align:start position:0% +you have to solve for the for the + + + align:start position:0% +you have to solve for the for the +coefficients a b c and d so I'm not + + align:start position:0% +coefficients a b c and d so I'm not + + + align:start position:0% +coefficients a b c and d so I'm not +going to write that out myself but I but + + align:start position:0% +going to write that out myself but I but + + + align:start position:0% +going to write that out myself but I but +I cleverly did it uh before before I + + align:start position:0% +I cleverly did it uh before before I + + + align:start position:0% +I cleverly did it uh before before I +came on camera so I can tell you what + + align:start position:0% +came on camera so I can tell you what + + + align:start position:0% +came on camera so I can tell you what +the answer is if if you want to check + + align:start position:0% +the answer is if if you want to check + + + align:start position:0% +the answer is if if you want to check +your work so here we have a is equal to + + align:start position:0% +your work so here we have a is equal to + + + align:start position:0% +your work so here we have a is equal to +zero B is equal + + align:start position:0% +zero B is equal + + + align:start position:0% +zero B is equal +1 C is equal to 1 and D is equal to + + align:start position:0% +1 C is equal to 1 and D is equal to + + + align:start position:0% +1 C is equal to 1 and D is equal to +minus 3 so that's for the I didn't write + + align:start position:0% +minus 3 so that's for the I didn't write + + + align:start position:0% +minus 3 so that's for the I didn't write +it over here that's for this particular + + align:start position:0% +it over here that's for this particular + + + align:start position:0% +it over here that's for this particular +numerator that we that we started with + + align:start position:0% +numerator that we that we started with + + + align:start position:0% +numerator that we that we started with +back over here the for so for this + + align:start position:0% +back over here the for so for this + + + align:start position:0% +back over here the for so for this +particular fraction if you if you carry + + align:start position:0% +particular fraction if you if you carry + + + align:start position:0% +particular fraction if you if you carry +out the partial fraction decomposition + + align:start position:0% +out the partial fraction decomposition + + + align:start position:0% +out the partial fraction decomposition +what you + + align:start position:0% +what you + + + align:start position:0% +what you +get is is right here so okay so those + + align:start position:0% +get is is right here so okay so those + + + align:start position:0% +get is is right here so okay so those +are that was a few more examples of the + + align:start position:0% +are that was a few more examples of the + + + align:start position:0% +are that was a few more examples of the +partial fraction decomposition um I hope + + align:start position:0% +partial fraction decomposition um I hope + + + align:start position:0% +partial fraction decomposition um I hope +hope you enjoyed them and I'm going to + + align:start position:0% +hope you enjoyed them and I'm going to + + + align:start position:0% +hope you enjoyed them and I'm going to +end there \ No newline at end of file diff --git a/UzMEzYQOFRA.txt b/UzMEzYQOFRA.txt new file mode 100644 index 0000000000000000000000000000000000000000..ba05c5251a4e70a9cfc93b40b2f9a7fc612be973 --- /dev/null +++ b/UzMEzYQOFRA.txt @@ -0,0 +1,8355 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT OpenCourseWare continue to + + align:start position:0% +will help MIT OpenCourseWare continue to + + + align:start position:0% +will help MIT OpenCourseWare continue to +offer high quality educational resources + + align:start position:0% +offer high quality educational resources + + + align:start position:0% +offer high quality educational resources +for free + + align:start position:0% +for free + + + align:start position:0% +for free +to make a donation or view additional + + align:start position:0% +to make a donation or view additional + + + align:start position:0% +to make a donation or view additional +materials from hundreds of MIT courses + + align:start position:0% +materials from hundreds of MIT courses + + + align:start position:0% +materials from hundreds of MIT courses +visit MIT opencourseware at ocw.mit.edu + + align:start position:0% + + + + align:start position:0% + +iron homeostasis and module six and then + + align:start position:0% +iron homeostasis and module six and then + + + align:start position:0% +iron homeostasis and module six and then +we're going to move on to module 7 and + + align:start position:0% +we're going to move on to module 7 and + + + align:start position:0% +we're going to move on to module 7 and +the readings have been posted and the + + align:start position:0% +the readings have been posted and the + + + align:start position:0% +the readings have been posted and the +PowerPoint has been posted for today's + + align:start position:0% +PowerPoint has been posted for today's + + + align:start position:0% +PowerPoint has been posted for today's +lecture as well okay so we were talking + + align:start position:0% +lecture as well okay so we were talking + + + align:start position:0% +lecture as well okay so we were talking +about last time peptidoglycan x' and + + align:start position:0% +about last time peptidoglycan x' and + + + align:start position:0% +about last time peptidoglycan x' and +gram-positive bacteria and they're + + align:start position:0% +gram-positive bacteria and they're + + + align:start position:0% +gram-positive bacteria and they're +actually quite thick depending on the + + align:start position:0% +actually quite thick depending on the + + + align:start position:0% +actually quite thick depending on the +organism and so what is the strategy + + align:start position:0% +organism and so what is the strategy + + + align:start position:0% +organism and so what is the strategy +nature uses to be able to pick up iron + + align:start position:0% +nature uses to be able to pick up iron + + + align:start position:0% +nature uses to be able to pick up iron +where you have WIC where you have a + + align:start position:0% +where you have WIC where you have a + + + align:start position:0% +where you have WIC where you have a +bacteria surrounded by this huge pet + + align:start position:0% +bacteria surrounded by this huge pet + + + align:start position:0% +bacteria surrounded by this huge pet +that okhla I can and the strategy and + + align:start position:0% +that okhla I can and the strategy and + + + align:start position:0% +that okhla I can and the strategy and +staph aureus that has evolved is they + + align:start position:0% +staph aureus that has evolved is they + + + align:start position:0% +staph aureus that has evolved is they +attach everything almost everything + + align:start position:0% +attach everything almost everything + + + align:start position:0% +attach everything almost everything +covalently to the peptidoglycan itself + + align:start position:0% +covalently to the peptidoglycan itself + + + align:start position:0% +covalently to the peptidoglycan itself +so at the end of the last lecture we + + align:start position:0% +so at the end of the last lecture we + + + align:start position:0% +so at the end of the last lecture we +were looking at we introduced you to the + + align:start position:0% +were looking at we introduced you to the + + + align:start position:0% +were looking at we introduced you to the +operon and staph aureus and there were + + align:start position:0% +operon and staph aureus and there were + + + align:start position:0% +operon and staph aureus and there were +proteins called sore cases which are + + align:start position:0% +proteins called sore cases which are + + + align:start position:0% +proteins called sore cases which are +transpeptidase is really basically and + + align:start position:0% +transpeptidase is really basically and + + + align:start position:0% +transpeptidase is really basically and +they have different sequence + + align:start position:0% +they have different sequence + + + align:start position:0% +they have different sequence +specificities and just go back one so + + align:start position:0% +specificities and just go back one so + + + align:start position:0% +specificities and just go back one so +where we were last time we have this + + align:start position:0% +where we were last time we have this + + + align:start position:0% +where we were last time we have this +operon and all of the proteins that are + + align:start position:0% +operon and all of the proteins that are + + + align:start position:0% +operon and all of the proteins that are +going to be involved in uptake of heme + + align:start position:0% +going to be involved in uptake of heme + + + align:start position:0% +going to be involved in uptake of heme +into the cell are called the isd + + align:start position:0% +into the cell are called the isd + + + align:start position:0% +into the cell are called the isd +proteins and so here's the operon and + + align:start position:0% +proteins and so here's the operon and + + + align:start position:0% +proteins and so here's the operon and +you could see that each part of this + + align:start position:0% +you could see that each part of this + + + align:start position:0% +you could see that each part of this +operon is activated by a fur box of fur + + align:start position:0% +operon is activated by a fur box of fur + + + align:start position:0% +operon is activated by a fur box of fur +boxes the transcriptional factor that + + align:start position:0% +boxes the transcriptional factor that + + + align:start position:0% +boxes the transcriptional factor that +turns off or on regulation at the + + align:start position:0% +turns off or on regulation at the + + + align:start position:0% +turns off or on regulation at the +transcriptional level by the presence or + + align:start position:0% +transcriptional level by the presence or + + + align:start position:0% +transcriptional level by the presence or +absence of iron which we're not going to + + align:start position:0% +absence of iron which we're not going to + + + align:start position:0% +absence of iron which we're not going to +talk about further and what I wanted to + + align:start position:0% +talk about further and what I wanted to + + + align:start position:0% +talk about further and what I wanted to +point out here before we move on is that + + align:start position:0% +point out here before we move on is that + + + align:start position:0% +point out here before we move on is that +all of the yellow anchors are proteins + + align:start position:0% +all of the yellow anchors are proteins + + + align:start position:0% +all of the yellow anchors are proteins +that are couch covalently by sort a they + + align:start position:0% +that are couch covalently by sort a they + + + align:start position:0% +that are couch covalently by sort a they +okay which has a defined zip code the + + align:start position:0% +okay which has a defined zip code the + + + align:start position:0% +okay which has a defined zip code the +blue in is d c has its own sort a sort + + align:start position:0% +blue in is d c has its own sort a sort + + + align:start position:0% +blue in is d c has its own sort a sort +a's b and is de is not attached + + align:start position:0% +a's b and is de is not attached + + + align:start position:0% +a's b and is de is not attached +covalently to the peptidoglycan but + + align:start position:0% +covalently to the peptidoglycan but + + + align:start position:0% +covalently to the peptidoglycan but +actually has membrane + + align:start position:0% +actually has membrane + + + align:start position:0% +actually has membrane +covalently to a lipid which is then + + align:start position:0% +covalently to a lipid which is then + + + align:start position:0% +covalently to a lipid which is then +inserted into the membrane which is the + + align:start position:0% +inserted into the membrane which is the + + + align:start position:0% +inserted into the membrane which is the +other strategy that's used in these + + align:start position:0% +other strategy that's used in these + + + align:start position:0% +other strategy that's used in these +systems and let me just point out you + + align:start position:0% +systems and let me just point out you + + + align:start position:0% +systems and let me just point out you +saw this I'm not going to spend much + + align:start position:0% +saw this I'm not going to spend much + + + align:start position:0% +saw this I'm not going to spend much +time on this today because you've + + align:start position:0% +time on this today because you've + + + align:start position:0% +time on this today because you've +already had a problem and your last + + align:start position:0% +already had a problem and your last + + + align:start position:0% +already had a problem and your last +problem was set on this but you have + + align:start position:0% +problem was set on this but you have + + + align:start position:0% +problem was set on this but you have +these little n domains and the neat + + align:start position:0% +these little n domains and the neat + + + align:start position:0% +these little n domains and the neat +domains which are 120 amino acid domains + + align:start position:0% +domains which are 120 amino acid domains + + + align:start position:0% +domains which are 120 amino acid domains +that allow you to pick up team and are + + align:start position:0% +that allow you to pick up team and are + + + align:start position:0% +that allow you to pick up team and are +involved and transfer of heme down a + + align:start position:0% +involved and transfer of heme down a + + + align:start position:0% +involved and transfer of heme down a +brach bucket for grade so what we're + + align:start position:0% +brach bucket for grade so what we're + + + align:start position:0% +brach bucket for grade so what we're +trying to do is attach these ISDN + + align:start position:0% +trying to do is attach these ISDN + + + align:start position:0% +trying to do is attach these ISDN +proteins to the peptidoglycan how it + + align:start position:0% +proteins to the peptidoglycan how it + + + align:start position:0% +proteins to the peptidoglycan how it +does that how they end up being + + align:start position:0% +does that how they end up being + + + align:start position:0% +does that how they end up being +organized how many there are is all an + + align:start position:0% +organized how many there are is all an + + + align:start position:0% +organized how many there are is all an +active area of research we don't really + + align:start position:0% +active area of research we don't really + + + align:start position:0% +active area of research we don't really +know that somebody might know it but + + align:start position:0% +know that somebody might know it but + + + align:start position:0% +know that somebody might know it but +it's not in the published literature and + + align:start position:0% +it's not in the published literature and + + + align:start position:0% +it's not in the published literature and +so the idea is again you can see all of + + align:start position:0% +so the idea is again you can see all of + + + align:start position:0% +so the idea is again you can see all of +these proteins in some way of tethered + + align:start position:0% +these proteins in some way of tethered + + + align:start position:0% +these proteins in some way of tethered +via usually a single trans membrane + + align:start position:0% +via usually a single trans membrane + + + align:start position:0% +via usually a single trans membrane +spanning region in the protein and + + align:start position:0% +spanning region in the protein and + + + align:start position:0% +spanning region in the protein and +here's one ISD protein here with a + + align:start position:0% +here's one ISD protein here with a + + + align:start position:0% +here's one ISD protein here with a +little zip code and it involves two + + align:start position:0% +little zip code and it involves two + + + align:start position:0% +little zip code and it involves two +sorties a which you've now seen over and + + align:start position:0% +sorties a which you've now seen over and + + + align:start position:0% +sorties a which you've now seen over and +over again happens to have a cysteine in + + align:start position:0% +over again happens to have a cysteine in + + + align:start position:0% +over again happens to have a cysteine in +its active site to go through a covalent + + align:start position:0% +its active site to go through a covalent + + + align:start position:0% +its active site to go through a covalent +bond formation and you're going to be + + align:start position:0% +bond formation and you're going to be + + + align:start position:0% +bond formation and you're going to be +cleaving one peptide bond and forming + + align:start position:0% +cleaving one peptide bond and forming + + + align:start position:0% +cleaving one peptide bond and forming +another peptide bond where have you seen + + align:start position:0% +another peptide bond where have you seen + + + align:start position:0% +another peptide bond where have you seen +that before + + align:start position:0% +that before + + + align:start position:0% +that before +that's how you did cross linking the + + align:start position:0% +that's how you did cross linking the + + + align:start position:0% +that's how you did cross linking the +transpeptidase it transpeptidase in + + align:start position:0% +transpeptidase it transpeptidase in + + + align:start position:0% +transpeptidase it transpeptidase in +reaction we talked about last time that + + align:start position:0% +reaction we talked about last time that + + + align:start position:0% +reaction we talked about last time that +allows you to form the bag and the bag + + align:start position:0% +allows you to form the bag and the bag + + + align:start position:0% +allows you to form the bag and the bag +of peptidoglycan x' becomes cross-linked + + align:start position:0% +of peptidoglycan x' becomes cross-linked + + + align:start position:0% +of peptidoglycan x' becomes cross-linked +and that's the key to survival of the + + align:start position:0% +and that's the key to survival of the + + + align:start position:0% +and that's the key to survival of the +organism and so you cleave this bond + + align:start position:0% +organism and so you cleave this bond + + + align:start position:0% +organism and so you cleave this bond +between t and g the specificity is + + align:start position:0% +between t and g the specificity is + + + align:start position:0% +between t and g the specificity is +understood and people in the Penta + + align:start position:0% +understood and people in the Penta + + + align:start position:0% +understood and people in the Penta +Lutece lab use sortase quite a bit but + + align:start position:0% +Lutece lab use sortase quite a bit but + + + align:start position:0% +Lutece lab use sortase quite a bit but +it has been engineered by the Luo lab to + + align:start position:0% +it has been engineered by the Luo lab to + + + align:start position:0% +it has been engineered by the Luo lab to +be more efficient as a catalyst so this + + align:start position:0% +be more efficient as a catalyst so this + + + align:start position:0% +be more efficient as a catalyst so this +is a natural catalyst you do a trance + + align:start position:0% +is a natural catalyst you do a trance + + + align:start position:0% +is a natural catalyst you do a trance +peptide pected asian reaction and then + + align:start position:0% +peptide pected asian reaction and then + + + align:start position:0% +peptide pected asian reaction and then +you have this is to me what's amazing + + align:start position:0% +you have this is to me what's amazing + + + align:start position:0% +you have this is to me what's amazing +you have this lipid 2 which is that c55 + + align:start position:0% +you have this lipid 2 which is that c55 + + + align:start position:0% +you have this lipid 2 which is that c55 +isoprene system with the pentacle I seen + + align:start position:0% +isoprene system with the pentacle I seen + + + align:start position:0% +isoprene system with the pentacle I seen +hanging + + align:start position:0% +hanging + + + align:start position:0% +hanging +the pentapeptide all of which is + + align:start position:0% +the pentapeptide all of which is + + + align:start position:0% +the pentapeptide all of which is +generated on the inside of the cell and + + align:start position:0% +generated on the inside of the cell and + + + align:start position:0% +generated on the inside of the cell and +gets transferred to the outside of the + + align:start position:0% +gets transferred to the outside of the + + + align:start position:0% +gets transferred to the outside of the +cell one then is set up to do peptide + + align:start position:0% +cell one then is set up to do peptide + + + align:start position:0% +cell one then is set up to do peptide +bond formation just like just like we + + align:start position:0% +bond formation just like just like we + + + align:start position:0% +bond formation just like just like we +saw with the transpeptidase reaction and + + align:start position:0% +saw with the transpeptidase reaction and + + + align:start position:0% +saw with the transpeptidase reaction and +so you end up with in this lipid lipid + + align:start position:0% +so you end up with in this lipid lipid + + + align:start position:0% +so you end up with in this lipid lipid +too attached to the ISDN protein okay + + align:start position:0% +too attached to the ISDN protein okay + + + align:start position:0% +too attached to the ISDN protein okay +and then that's taken the so this is the + + align:start position:0% +and then that's taken the so this is the + + + align:start position:0% +and then that's taken the so this is the +detailed chemistry that we just + + align:start position:0% +detailed chemistry that we just + + + align:start position:0% +detailed chemistry that we just +discussed and you can go through it + + align:start position:0% +discussed and you can go through it + + + align:start position:0% +discussed and you can go through it +again if you don't remember it but it's + + align:start position:0% +again if you don't remember it but it's + + + align:start position:0% +again if you don't remember it but it's +very similar to the things we've now + + align:start position:0% +very similar to the things we've now + + + align:start position:0% +very similar to the things we've now +seen many many times in this course so + + align:start position:0% +seen many many times in this course so + + + align:start position:0% +seen many many times in this course so +once you attach this what happens is it + + align:start position:0% +once you attach this what happens is it + + + align:start position:0% +once you attach this what happens is it +gets transferred the whole thing now + + align:start position:0% +gets transferred the whole thing now + + + align:start position:0% +gets transferred the whole thing now +gets transferred by the mechanism + + align:start position:0% +gets transferred by the mechanism + + + align:start position:0% +gets transferred by the mechanism +similar to forming the polymer but now + + align:start position:0% +similar to forming the polymer but now + + + align:start position:0% +similar to forming the polymer but now +you have the pentacle I seen with an + + align:start position:0% +you have the pentacle I seen with an + + + align:start position:0% +you have the pentacle I seen with an +ISDN protein attached as well and so you + + align:start position:0% +ISDN protein attached as well and so you + + + align:start position:0% +ISDN protein attached as well and so you +can see then this is the growing + + align:start position:0% + + + + align:start position:0% + +peptidoglycan with alternating units of + + align:start position:0% +peptidoglycan with alternating units of + + + align:start position:0% +peptidoglycan with alternating units of +an acetyl glucosamine and SAT Lee Remick + + align:start position:0% +an acetyl glucosamine and SAT Lee Remick + + + align:start position:0% +an acetyl glucosamine and SAT Lee Remick +acid we talked about last time and now + + align:start position:0% +acid we talked about last time and now + + + align:start position:0% +acid we talked about last time and now +we have the ISDN protein covalently + + align:start position:0% +we have the ISDN protein covalently + + + align:start position:0% +we have the ISDN protein covalently +attached so this is a pretty amazing + + align:start position:0% +attached so this is a pretty amazing + + + align:start position:0% +attached so this is a pretty amazing +strategy and you can imagine trying to + + align:start position:0% +strategy and you can imagine trying to + + + align:start position:0% +strategy and you can imagine trying to +study this under natural systems with + + align:start position:0% +study this under natural systems with + + + align:start position:0% +study this under natural systems with +everything attached is quite challenging + + align:start position:0% +everything attached is quite challenging + + + align:start position:0% +everything attached is quite challenging +and so the problem you had on the + + align:start position:0% +and so the problem you had on the + + + align:start position:0% +and so the problem you had on the +problem set what do they do they cut + + align:start position:0% +problem set what do they do they cut + + + align:start position:0% +problem set what do they do they cut +everything off and all you're looking at + + align:start position:0% +everything off and all you're looking at + + + align:start position:0% +everything off and all you're looking at +is a little piece of the protein not the + + align:start position:0% +is a little piece of the protein not the + + + align:start position:0% +is a little piece of the protein not the +whole protein anchored in this way with + + align:start position:0% +whole protein anchored in this way with + + + align:start position:0% +whole protein anchored in this way with +the right topology in the active site so + + align:start position:0% +the right topology in the active site so + + + align:start position:0% +the right topology in the active site so +to me even thinking about how you make a + + align:start position:0% +to me even thinking about how you make a + + + align:start position:0% +to me even thinking about how you make a +peptidoglycan that's 50 50 nanometers + + align:start position:0% +peptidoglycan that's 50 50 nanometers + + + align:start position:0% +peptidoglycan that's 50 50 nanometers +thick you know + + align:start position:0% +thick you know + + + align:start position:0% +thick you know +so you add things how does it construct + + align:start position:0% +so you add things how does it construct + + + align:start position:0% +so you add things how does it construct +yourself a cyclist around this system + + align:start position:0% +yourself a cyclist around this system + + + align:start position:0% +yourself a cyclist around this system +and build up I think nobody knows that + + align:start position:0% +and build up I think nobody knows that + + + align:start position:0% +and build up I think nobody knows that +and recent studies have been able to the + + align:start position:0% +and recent studies have been able to the + + + align:start position:0% +and recent studies have been able to the +first time to in staph.aureus + + align:start position:0% +first time to in staph.aureus + + + align:start position:0% +first time to in staph.aureus +reconstitute transpeptidase in and the + + align:start position:0% +reconstitute transpeptidase in and the + + + align:start position:0% +reconstitute transpeptidase in and the +glycosyl transferase reaction so maybe + + align:start position:0% +glycosyl transferase reaction so maybe + + + align:start position:0% +glycosyl transferase reaction so maybe +that with a sort of an imaging + + align:start position:0% +that with a sort of an imaging + + + align:start position:0% +that with a sort of an imaging +technology we have maybe in the next + + align:start position:0% +technology we have maybe in the next + + + align:start position:0% +technology we have maybe in the next +five or six years somebody + + align:start position:0% +five or six years somebody + + + align:start position:0% +five or six years somebody +we'll figure out how this amazing thing + + align:start position:0% +we'll figure out how this amazing thing + + + align:start position:0% +we'll figure out how this amazing thing +is organized so anyhow we were able to + + align:start position:0% +is organized so anyhow we were able to + + + align:start position:0% +is organized so anyhow we were able to +attach these things covalently and so + + align:start position:0% +attach these things covalently and so + + + align:start position:0% +attach these things covalently and so +here we are we've got these all all of + + align:start position:0% +here we are we've got these all all of + + + align:start position:0% +here we are we've got these all all of +these things anchored and then in your + + align:start position:0% +these things anchored and then in your + + + align:start position:0% +these things anchored and then in your +problem set and in the last part of this + + align:start position:0% +problem set and in the last part of this + + + align:start position:0% +problem set and in the last part of this +I just wanted to very briefly go through + + align:start position:0% +I just wanted to very briefly go through + + + align:start position:0% +I just wanted to very briefly go through +how are people trying to study how the + + align:start position:0% +how are people trying to study how the + + + align:start position:0% +how are people trying to study how the +heme that appear gets transferred and so + + align:start position:0% +heme that appear gets transferred and so + + + align:start position:0% +heme that appear gets transferred and so +this is a cartoon model and so we have + + align:start position:0% +this is a cartoon model and so we have + + + align:start position:0% +this is a cartoon model and so we have +hemoglobin we've been able to get we've + + align:start position:0% +hemoglobin we've been able to get we've + + + align:start position:0% +hemoglobin we've been able to get we've +been able to lyse red blood cells get + + align:start position:0% +been able to lyse red blood cells get + + + align:start position:0% +been able to lyse red blood cells get +the get hemoglobin to come out or have + + align:start position:0% +the get hemoglobin to come out or have + + + align:start position:0% +the get hemoglobin to come out or have +to get globin hemoglobin and now somehow + + align:start position:0% +to get globin hemoglobin and now somehow + + + align:start position:0% +to get globin hemoglobin and now somehow +you have to extract the heme and that's + + align:start position:0% +you have to extract the heme and that's + + + align:start position:0% +you have to extract the heme and that's +done by two proteins is B B and H and + + align:start position:0% +done by two proteins is B B and H and + + + align:start position:0% +done by two proteins is B B and H and +then we somehow have to get it to the + + align:start position:0% +then we somehow have to get it to the + + + align:start position:0% +then we somehow have to get it to the +plasma membrane and so the model is that + + align:start position:0% +plasma membrane and so the model is that + + + align:start position:0% +plasma membrane and so the model is that +this is transferred from IsdB through a + + align:start position:0% +this is transferred from IsdB through a + + + align:start position:0% +this is transferred from IsdB through a +neat domain okay so all of these + + align:start position:0% +neat domain okay so all of these + + + align:start position:0% +neat domain okay so all of these +transfers up to here are through these + + align:start position:0% +transfers up to here are through these + + + align:start position:0% +transfers up to here are through these +little domains that can bind him and we + + align:start position:0% +little domains that can bind him and we + + + align:start position:0% +little domains that can bind him and we +have a structure of it I'll briefly show + + align:start position:0% +have a structure of it I'll briefly show + + + align:start position:0% +have a structure of it I'll briefly show +you that and then the question is there + + align:start position:0% +you that and then the question is there + + + align:start position:0% +you that and then the question is there +in order if you get it out of is DB vs. + + align:start position:0% +in order if you get it out of is DB vs. + + + align:start position:0% +in order if you get it out of is DB vs. +is th is it transferred you know here we + + align:start position:0% +is th is it transferred you know here we + + + align:start position:0% +is th is it transferred you know here we +have a closer to this than B but is is C + + align:start position:0% +have a closer to this than B but is is C + + + align:start position:0% +have a closer to this than B but is is C +closer than a I mean what is the + + align:start position:0% +closer than a I mean what is the + + + align:start position:0% +closer than a I mean what is the +organization how many of these guys are + + align:start position:0% +organization how many of these guys are + + + align:start position:0% +organization how many of these guys are +there can they be transferred back and + + align:start position:0% +there can they be transferred back and + + + align:start position:0% +there can they be transferred back and +forth between the is das I mean there's + + align:start position:0% +forth between the is das I mean there's + + + align:start position:0% +forth between the is das I mean there's +a hundred questions you can ask and I + + align:start position:0% +a hundred questions you can ask and I + + + align:start position:0% +a hundred questions you can ask and I +think we don't know the answer to any of + + align:start position:0% +think we don't know the answer to any of + + + align:start position:0% +think we don't know the answer to any of +them and the methodology the problems + + align:start position:0% +them and the methodology the problems + + + align:start position:0% +them and the methodology the problems +that you looked at again they were + + align:start position:0% +that you looked at again they were + + + align:start position:0% +that you looked at again they were +looking at something that wasn't the + + align:start position:0% +looking at something that wasn't the + + + align:start position:0% +looking at something that wasn't the +intact system and the key to all of this + + align:start position:0% +intact system and the key to all of this + + + align:start position:0% +intact system and the key to all of this +of course is a kinetics and I think when + + align:start position:0% +of course is a kinetics and I think when + + + align:start position:0% +of course is a kinetics and I think when +you start taking apart the pieces so you + + align:start position:0% +you start taking apart the pieces so you + + + align:start position:0% +you start taking apart the pieces so you +have this piece and this piece and half + + align:start position:0% +have this piece and this piece and half + + + align:start position:0% +have this piece and this piece and half +the spinach is is missing then you have + + align:start position:0% +the spinach is is missing then you have + + + align:start position:0% +the spinach is is missing then you have +this issue of how do you design the + + align:start position:0% +this issue of how do you design the + + + align:start position:0% +this issue of how do you design the +experiment so you have the right + + align:start position:0% +experiment so you have the right + + + align:start position:0% +experiment so you have the right +concentrations so they meet + + align:start position:0% +concentrations so they meet + + + align:start position:0% +concentrations so they meet +um in an efficient facet fashion and so + + align:start position:0% +um in an efficient facet fashion and so + + + align:start position:0% +um in an efficient facet fashion and so +the kinetics of what you were looking at + + align:start position:0% +the kinetics of what you were looking at + + + align:start position:0% +the kinetics of what you were looking at +and your problems that are not realistic + + align:start position:0% +and your problems that are not realistic + + + align:start position:0% +and your problems that are not realistic +because things aren't covalently + + align:start position:0% +because things aren't covalently + + + align:start position:0% +because things aren't covalently +attached and so the question is does it + + align:start position:0% +attached and so the question is does it + + + align:start position:0% +attached and so the question is does it +really give you a good representation of + + align:start position:0% +really give you a good representation of + + + align:start position:0% +really give you a good representation of +what's going on in the intact system so + + align:start position:0% +what's going on in the intact system so + + + align:start position:0% +what's going on in the intact system so +the model has been from studies like the + + align:start position:0% +the model has been from studies like the + + + align:start position:0% +the model has been from studies like the +ones that you saw in your problem set + + align:start position:0% +ones that you saw in your problem set + + + align:start position:0% +ones that you saw in your problem set +that there is a pathway that this + + align:start position:0% +that there is a pathway that this + + + align:start position:0% +that there is a pathway that this +protein can extract the B and the H + + align:start position:0% +protein can extract the B and the H + + + align:start position:0% +protein can extract the B and the H +proteins can extract the heme it's + + align:start position:0% +proteins can extract the heme it's + + + align:start position:0% +proteins can extract the heme it's +transferred to the a protein and so here + + align:start position:0% +transferred to the a protein and so here + + + align:start position:0% +transferred to the a protein and so here +we have can it be transferred directly + + align:start position:0% +we have can it be transferred directly + + + align:start position:0% +we have can it be transferred directly +to the C protein or it doesn't need to + + align:start position:0% +to the C protein or it doesn't need to + + + align:start position:0% +to the C protein or it doesn't need to +go through the a protein so then you can + + align:start position:0% +go through the a protein so then you can + + + align:start position:0% +go through the a protein so then you can +start doing experiments like that you + + align:start position:0% +start doing experiments like that you + + + align:start position:0% +start doing experiments like that you +can take this protein and look for + + align:start position:0% +can take this protein and look for + + + align:start position:0% +can take this protein and look for +transfer to this protein or you can add + + align:start position:0% +transfer to this protein or you can add + + + align:start position:0% +transfer to this protein or you can add +in this protein and see if the rate if + + align:start position:0% +in this protein and see if the rate if + + + align:start position:0% +in this protein and see if the rate if +you set the experimental correctly + + align:start position:0% +you set the experimental correctly + + + align:start position:0% +you set the experimental correctly +increases you can also ask the question + + align:start position:0% +increases you can also ask the question + + + align:start position:0% +increases you can also ask the question +are these reactions stoichiometric or + + align:start position:0% +are these reactions stoichiometric or + + + align:start position:0% +are these reactions stoichiometric or +catalytic which was also asked in the + + align:start position:0% +catalytic which was also asked in the + + + align:start position:0% +catalytic which was also asked in the +problem set you were looking at if you + + align:start position:0% +problem set you were looking at if you + + + align:start position:0% +problem set you were looking at if you +if this if there is an order how fast is + + align:start position:0% +if this if there is an order how fast is + + + align:start position:0% +if this if there is an order how fast is +the transfer from here to here versus + + align:start position:0% +the transfer from here to here versus + + + align:start position:0% +the transfer from here to here versus +here to here and if it's really fast + + align:start position:0% +here to here and if it's really fast + + + align:start position:0% +here to here and if it's really fast +what can happen is you don't need + + align:start position:0% +what can happen is you don't need + + + align:start position:0% +what can happen is you don't need +stoichiometric amounts of this you can + + align:start position:0% +stoichiometric amounts of this you can + + + align:start position:0% +stoichiometric amounts of this you can +use small amounts of this to get the + + align:start position:0% +use small amounts of this to get the + + + align:start position:0% +use small amounts of this to get the +transfer to work and those are the kinds + + align:start position:0% +transfer to work and those are the kinds + + + align:start position:0% +transfer to work and those are the kinds +of questions that people are actually + + align:start position:0% +of questions that people are actually + + + align:start position:0% +of questions that people are actually +focused on so this is one model that + + align:start position:0% +focused on so this is one model that + + + align:start position:0% +focused on so this is one model that +came out are the types of studies that + + align:start position:0% +came out are the types of studies that + + + align:start position:0% +came out are the types of studies that +you guys had on your problem set and + + align:start position:0% +you guys had on your problem set and + + + align:start position:0% +you guys had on your problem set and +eventually you need to get down here to + + align:start position:0% +eventually you need to get down here to + + + align:start position:0% +eventually you need to get down here to +transfer this to the ATP A's which + + align:start position:0% +transfer this to the ATP A's which + + + align:start position:0% +transfer this to the ATP A's which +allows the heme to be transferred into + + align:start position:0% +allows the heme to be transferred into + + + align:start position:0% +allows the heme to be transferred into +the cytosol so these proteins are + + align:start position:0% +the cytosol so these proteins are + + + align:start position:0% +the cytosol so these proteins are +structurally distinct from this protein + + align:start position:0% +structurally distinct from this protein + + + align:start position:0% +structurally distinct from this protein +which is structurally distinct from that + + align:start position:0% +which is structurally distinct from that + + + align:start position:0% +which is structurally distinct from that +protein we have structures of always + + align:start position:0% +protein we have structures of always + + + align:start position:0% +protein we have structures of always +these things and they all do heme + + align:start position:0% +these things and they all do heme + + + align:start position:0% +these things and they all do heme +transfer I mean that's what their + + align:start position:0% +transfer I mean that's what their + + + align:start position:0% +transfer I mean that's what their +function actually is and so the details + + align:start position:0% +function actually is and so the details + + + align:start position:0% +function actually is and so the details +the molecular details of how the heme is + + align:start position:0% +the molecular details of how the heme is + + + align:start position:0% +the molecular details of how the heme is +transferred is a major focus of a lot of + + align:start position:0% +transferred is a major focus of a lot of + + + align:start position:0% +transferred is a major focus of a lot of +energy right now and so if you actually + + align:start position:0% +energy right now and so if you actually + + + align:start position:0% +energy right now and so if you actually +look at this + + align:start position:0% +look at this + + + align:start position:0% +look at this +I wanted to say a few things about how + + align:start position:0% +I wanted to say a few things about how + + + align:start position:0% +I wanted to say a few things about how +this happens and so one of the things + + align:start position:0% +this happens and so one of the things + + + align:start position:0% +this happens and so one of the things +that you need to think about so what are + + align:start position:0% +that you need to think about so what are + + + align:start position:0% +that you need to think about so what are +the methods to examine i SD team + + align:start position:0% +the methods to examine i SD team + + + align:start position:0% +the methods to examine i SD team +transfer and this is through these neat + + align:start position:0% +transfer and this is through these neat + + + align:start position:0% +transfer and this is through these neat +domains which I defined before and so + + align:start position:0% +domains which I defined before and so + + + align:start position:0% +domains which I defined before and so +one of the first things that people did + + align:start position:0% +one of the first things that people did + + + align:start position:0% +one of the first things that people did +was number one you need to you need to + + align:start position:0% +was number one you need to you need to + + + align:start position:0% +was number one you need to you need to +clone Express purify the the ISDN + + align:start position:0% +clone Express purify the the ISDN + + + align:start position:0% +clone Express purify the the ISDN +proteins and most of these studies have + + align:start position:0% +proteins and most of these studies have + + + align:start position:0% +proteins and most of these studies have +been done in pieces versus foam lengths + + align:start position:0% +been done in pieces versus foam lengths + + + align:start position:0% +been done in pieces versus foam lengths +okay and when you do so you could try to + + align:start position:0% +okay and when you do so you could try to + + + align:start position:0% +okay and when you do so you could try to +do the whole thing some of these things + + align:start position:0% +do the whole thing some of these things + + + align:start position:0% +do the whole thing some of these things +have three neat domains some have one + + align:start position:0% +have three neat domains some have one + + + align:start position:0% +have three neat domains some have one +neat domain if you look in those + + align:start position:0% +neat domain if you look in those + + + align:start position:0% +neat domain if you look in those +cartoons I gave you the number of neat + + align:start position:0% +cartoons I gave you the number of neat + + + align:start position:0% +cartoons I gave you the number of neat +domains are defined by sequences so you + + align:start position:0% +domains are defined by sequences so you + + + align:start position:0% +domains are defined by sequences so you +can study the full length thing or the + + align:start position:0% +can study the full length thing or the + + + align:start position:0% +can study the full length thing or the +other one and in fact I think in your + + align:start position:0% +other one and in fact I think in your + + + align:start position:0% +other one and in fact I think in your +problem said I can't remember but the + + align:start position:0% +problem said I can't remember but the + + + align:start position:0% +problem said I can't remember but the +problem said I think you actually you + + align:start position:0% +problem said I think you actually you + + + align:start position:0% +problem said I think you actually you +actually didn't expect was an experiment + + align:start position:0% +actually didn't expect was an experiment + + + align:start position:0% +actually didn't expect was an experiment +that you had one at one neat domain + + align:start position:0% +that you had one at one neat domain + + + align:start position:0% +that you had one at one neat domain +versus two and what was the differences + + align:start position:0% +versus two and what was the differences + + + align:start position:0% +versus two and what was the differences +in the transfer so you can make these + + align:start position:0% +in the transfer so you can make these + + + align:start position:0% +in the transfer so you can make these +things but when you make some hemas + + align:start position:0% +things but when you make some hemas + + + align:start position:0% +things but when you make some hemas +quite often because their bio synthetic + + align:start position:0% +quite often because their bio synthetic + + + align:start position:0% +quite often because their bio synthetic +machinery like there is to insert iron + + align:start position:0% +machinery like there is to insert iron + + + align:start position:0% +machinery like there is to insert iron +clusters biosynthetic on your clusters + + align:start position:0% +clusters biosynthetic on your clusters + + + align:start position:0% +clusters biosynthetic on your clusters +is also bio synthetic machinery to + + align:start position:0% +is also bio synthetic machinery to + + + align:start position:0% +is also bio synthetic machinery to +insert teams so it comes out these come + + align:start position:0% +insert teams so it comes out these come + + + align:start position:0% +insert teams so it comes out these come +out to be April ok so then what you need + + align:start position:0% +out to be April ok so then what you need + + + align:start position:0% +out to be April ok so then what you need +to do is you need to add a PO plus + + align:start position:0% + + + + align:start position:0% + +protoporphyrin 9 to get presumably hello + + align:start position:0% +protoporphyrin 9 to get presumably hello + + + align:start position:0% +protoporphyrin 9 to get presumably hello +ok + + align:start position:0% +ok + + + align:start position:0% +ok +holo whatever ISDN is + + align:start position:0% +holo whatever ISDN is + + + align:start position:0% +holo whatever ISDN is +and then you need to purify that you can + + align:start position:0% +and then you need to purify that you can + + + align:start position:0% +and then you need to purify that you can +get rid of any heme you don't have a + + align:start position:0% +get rid of any heme you don't have a + + + align:start position:0% +get rid of any heme you don't have a +bunch of heme floating around so it's an + + align:start position:0% +bunch of heme floating around so it's an + + + align:start position:0% +bunch of heme floating around so it's an +again yet another purification to look + + align:start position:0% +again yet another purification to look + + + align:start position:0% +again yet another purification to look +at all of this stuff that may or may not + + align:start position:0% +at all of this stuff that may or may not + + + align:start position:0% +at all of this stuff that may or may not +be easy and so then after you do that + + align:start position:0% +be easy and so then after you do that + + + align:start position:0% +be easy and so then after you do that +what you want to do is you need to + + align:start position:0% +what you want to do is you need to + + + align:start position:0% +what you want to do is you need to +characterize the spectra of the isd + + align:start position:0% +characterize the spectra of the isd + + + align:start position:0% +characterize the spectra of the isd +proteins loaded with him and so this is + + align:start position:0% +proteins loaded with him and so this is + + + align:start position:0% +proteins loaded with him and so this is +the key to the solution of the problem + + align:start position:0% +the key to the solution of the problem + + + align:start position:0% +the key to the solution of the problem +which is the same thing you saw in in + + align:start position:0% +which is the same thing you saw in in + + + align:start position:0% +which is the same thing you saw in in +your problem set but if you look at heme + + align:start position:0% +your problem set but if you look at heme + + + align:start position:0% +your problem set but if you look at heme +and I'll show you one set of data a + + align:start position:0% +and I'll show you one set of data a + + + align:start position:0% +and I'll show you one set of data a +different one from what you had in your + + align:start position:0% +different one from what you had in your + + + align:start position:0% +different one from what you had in your +problem set but heme you all know this + + align:start position:0% +problem set but heme you all know this + + + align:start position:0% +problem set but heme you all know this +from looking at hemoglobin when you + + align:start position:0% +from looking at hemoglobin when you + + + align:start position:0% +from looking at hemoglobin when you +bring your pick yourself and your + + align:start position:0% +bring your pick yourself and your + + + align:start position:0% +bring your pick yourself and your +bleeder thread or it's blue depending on + + align:start position:0% +bleeder thread or it's blue depending on + + + align:start position:0% +bleeder thread or it's blue depending on +the oxygenation state they have a very + + align:start position:0% +the oxygenation state they have a very + + + align:start position:0% +the oxygenation state they have a very +strong band called the sarey band at 400 + + align:start position:0% +strong band called the sarey band at 400 + + + align:start position:0% +strong band called the sarey band at 400 +nanometers okay about 100 okay and + + align:start position:0% +nanometers okay about 100 okay and + + + align:start position:0% +nanometers okay about 100 okay and +that's a key thing why do they like the + + align:start position:0% +that's a key thing why do they like the + + + align:start position:0% +that's a key thing why do they like the +Sylvania being because it has extremely + + align:start position:0% +Sylvania being because it has extremely + + + align:start position:0% +Sylvania being because it has extremely +high extinction coefficient I don't know + + align:start position:0% +high extinction coefficient I don't know + + + align:start position:0% +high extinction coefficient I don't know +what the number is but its extinction + + align:start position:0% +what the number is but its extinction + + + align:start position:0% +what the number is but its extinction +coefficient at 400 is approximately 10 + + align:start position:0% +coefficient at 400 is approximately 10 + + + align:start position:0% +coefficient at 400 is approximately 10 +to the fifth okay so it's easy to see + + align:start position:0% +to the fifth okay so it's easy to see + + + align:start position:0% +to the fifth okay so it's easy to see +that's why people have studied teams + + align:start position:0% +that's why people have studied teams + + + align:start position:0% +that's why people have studied teams +over the years because team is so much + + align:start position:0% +over the years because team is so much + + + align:start position:0% +over the years because team is so much +easier to see than any non heme iron + + align:start position:0% +easier to see than any non heme iron + + + align:start position:0% +easier to see than any non heme iron +systems and what you can see here what + + align:start position:0% +systems and what you can see here what + + + align:start position:0% +systems and what you can see here what +you're also turn out to be quite useful + + align:start position:0% +you're also turn out to be quite useful + + + align:start position:0% +you're also turn out to be quite useful +is these much weaker bands between 500 + + align:start position:0% +is these much weaker bands between 500 + + + align:start position:0% +is these much weaker bands between 500 +and 650 and those bands can also be used + + align:start position:0% +and 650 and those bands can also be used + + + align:start position:0% +and 650 and those bands can also be used +if you have enough sample to look at + + align:start position:0% +if you have enough sample to look at + + + align:start position:0% +if you have enough sample to look at +this and they're more distinct they're + + align:start position:0% +this and they're more distinct they're + + + align:start position:0% +this and they're more distinct they're +indicative of the coordination + + align:start position:0% +indicative of the coordination + + + align:start position:0% +indicative of the coordination +environment ahim whether it's whether + + align:start position:0% +environment ahim whether it's whether + + + align:start position:0% +environment ahim whether it's whether +it's hexa coordinated or whether it's + + align:start position:0% +it's hexa coordinated or whether it's + + + align:start position:0% +it's hexa coordinated or whether it's +Penta coordinate so all of this I'm not + + align:start position:0% +Penta coordinate so all of this I'm not + + + align:start position:0% +Penta coordinate so all of this I'm not +going to talk about the spectroscopy the + + align:start position:0% +going to talk about the spectroscopy the + + + align:start position:0% +going to talk about the spectroscopy the +spectroscopy of Hulme's has been + + align:start position:0% +spectroscopy of Hulme's has been + + + align:start position:0% +spectroscopy of Hulme's has been +extremely well studied and has extremely + + align:start position:0% +extremely well studied and has extremely + + + align:start position:0% +extremely well studied and has extremely +rich and so you need to do that you need + + align:start position:0% +rich and so you need to do that you need + + + align:start position:0% +rich and so you need to do that you need +to have your little proteins + + align:start position:0% +to have your little proteins + + + align:start position:0% +to have your little proteins +characterized and + + align:start position:0% +characterized and + + + align:start position:0% +characterized and +loaded with emu need to quantitate the + + align:start position:0% +loaded with emu need to quantitate the + + + align:start position:0% +loaded with emu need to quantitate the +amount of heme bones they want to make + + align:start position:0% +amount of heme bones they want to make + + + align:start position:0% +amount of heme bones they want to make +sure you don't have any free heme around + + align:start position:0% +sure you don't have any free heme around + + + align:start position:0% +sure you don't have any free heme around +which could interfere with all of your + + align:start position:0% +which could interfere with all of your + + + align:start position:0% +which could interfere with all of your +experiments and then you can ask the + + align:start position:0% +experiments and then you can ask the + + + align:start position:0% +experiments and then you can ask the +question you can start asking your + + align:start position:0% +question you can start asking your + + + align:start position:0% +question you can start asking your +questions once you've got that + + align:start position:0% +questions once you've got that + + + align:start position:0% +questions once you've got that +information if you start out with ISD a + + align:start position:0% +information if you start out with ISD a + + + align:start position:0% +information if you start out with ISD a +loaded with him does it gets transferred + + align:start position:0% +loaded with him does it gets transferred + + + align:start position:0% +loaded with him does it gets transferred +to is DC in the a po form okay and so + + align:start position:0% +to is DC in the a po form okay and so + + + align:start position:0% +to is DC in the a po form okay and so +how do you monitor this reaction anybody + + align:start position:0% +how do you monitor this reaction anybody + + + align:start position:0% +how do you monitor this reaction anybody +got any suggestions one way would be say + + align:start position:0% +got any suggestions one way would be say + + + align:start position:0% +got any suggestions one way would be say +one of the question that they're focused + + align:start position:0% +one of the question that they're focused + + + align:start position:0% +one of the question that they're focused +on here is does is da with a heme plus a + + align:start position:0% +on here is does is da with a heme plus a + + + align:start position:0% +on here is does is da with a heme plus a +PO is DC does it transfer the heme to + + align:start position:0% +PO is DC does it transfer the heme to + + + align:start position:0% +PO is DC does it transfer the heme to +give you a po i SG a + hm is DC and the + + align:start position:0% +give you a po i SG a + hm is DC and the + + + align:start position:0% +give you a po i SG a + hm is DC and the +question is what's the mechanism of this + + align:start position:0% +question is what's the mechanism of this + + + align:start position:0% +question is what's the mechanism of this +transfer so I just told you we have + + align:start position:0% +transfer so I just told you we have + + + align:start position:0% +transfer so I just told you we have +spectroscopy okay so I'm going to show + + align:start position:0% +spectroscopy okay so I'm going to show + + + align:start position:0% +spectroscopy okay so I'm going to show +you you could potentially do that that's + + align:start position:0% +you you could potentially do that that's + + + align:start position:0% +you you could potentially do that that's +not so easy to do but is there another + + align:start position:0% +not so easy to do but is there another + + + align:start position:0% +not so easy to do but is there another +method you can think of so we could + + align:start position:0% +method you can think of so we could + + + align:start position:0% +method you can think of so we could +monitor the reaction you need an assay + + align:start position:0% + + + + align:start position:0% + +okay and that's what you saw in your + + align:start position:0% +okay and that's what you saw in your + + + align:start position:0% +okay and that's what you saw in your +problem set so we can take advantage of + + align:start position:0% +problem set so we can take advantage of + + + align:start position:0% +problem set so we can take advantage of +the region of the saw a band or perhaps + + align:start position:0% +the region of the saw a band or perhaps + + + align:start position:0% +the region of the saw a band or perhaps +in the longer wavelength what other + + align:start position:0% +in the longer wavelength what other + + + align:start position:0% +in the longer wavelength what other +method might you be able to use to + + align:start position:0% +method might you be able to use to + + + align:start position:0% +method might you be able to use to +monitor this reaction that we've learned + + align:start position:0% +monitor this reaction that we've learned + + + align:start position:0% +monitor this reaction that we've learned +about recently in recitations which + + align:start position:0% +about recently in recitations which + + + align:start position:0% +about recently in recitations which +hasn't been used in the papers that + + align:start position:0% +hasn't been used in the papers that + + + align:start position:0% +hasn't been used in the papers that +you've read but actually has been used + + align:start position:0% +you've read but actually has been used + + + align:start position:0% +you've read but actually has been used +to study these systems + + align:start position:0% + + + + align:start position:0% + +yeah mass spec and so what people have + + align:start position:0% +yeah mass spec and so what people have + + + align:start position:0% +yeah mass spec and so what people have +done so you have to carry which what you + + align:start position:0% +done so you have to carry which what you + + + align:start position:0% +done so you have to carry which what you +will see is that if you look at the + + align:start position:0% +will see is that if you look at the + + + align:start position:0% +will see is that if you look at the +sizes of these things some have two neat + + align:start position:0% +sizes of these things some have two neat + + + align:start position:0% +sizes of these things some have two neat +domains want some have one the a PO also + + align:start position:0% +domains want some have one the a PO also + + + align:start position:0% +domains want some have one the a PO also +is distinct in size from the non a PO so + + align:start position:0% +is distinct in size from the non a PO so + + + align:start position:0% +is distinct in size from the non a PO so +theoretically if you do all of your + + align:start position:0% +theoretically if you do all of your + + + align:start position:0% +theoretically if you do all of your +homework you can use mass spec + + align:start position:0% +homework you can use mass spec + + + align:start position:0% +homework you can use mass spec +quantitatively to measure these + + align:start position:0% +quantitatively to measure these + + + align:start position:0% +quantitatively to measure these +reactions and a lot of people have + + align:start position:0% +reactions and a lot of people have + + + align:start position:0% +reactions and a lot of people have +recently gone to that that method + + align:start position:0% +recently gone to that that method + + + align:start position:0% +recently gone to that that method +because this method is challenging now + + align:start position:0% +because this method is challenging now + + + align:start position:0% +because this method is challenging now +again the caveat is so you always need + + align:start position:0% +again the caveat is so you always need + + + align:start position:0% +again the caveat is so you always need +to remember this is that all the ISD + + align:start position:0% +to remember this is that all the ISD + + + align:start position:0% +to remember this is that all the ISD +proteins are not covalently attached to + + align:start position:0% +proteins are not covalently attached to + + + align:start position:0% +proteins are not covalently attached to +the peptidoglycan okay so to me this + + align:start position:0% +the peptidoglycan okay so to me this + + + align:start position:0% +the peptidoglycan okay so to me this +immediately raises this issue of how do + + align:start position:0% +immediately raises this issue of how do + + + align:start position:0% +immediately raises this issue of how do +you decide how to do your experiments + + align:start position:0% +you decide how to do your experiments + + + align:start position:0% +you decide how to do your experiments +you know so how much do use micro molar + + align:start position:0% +you know so how much do use micro molar + + + align:start position:0% +you know so how much do use micro molar +do use do you use milli molar do you is + + align:start position:0% +do use do you use milli molar do you is + + + align:start position:0% +do use do you use milli molar do you is +it is it widely different depending on + + align:start position:0% +it is it widely different depending on + + + align:start position:0% +it is it widely different depending on +whether it's attached or not attached + + align:start position:0% +whether it's attached or not attached + + + align:start position:0% +whether it's attached or not attached +and all of that is going to affect the + + align:start position:0% +and all of that is going to affect the + + + align:start position:0% +and all of that is going to affect the +kinetics of this transfer so you can see + + align:start position:0% +kinetics of this transfer so you can see + + + align:start position:0% +kinetics of this transfer so you can see +transfer but what you really want is the + + align:start position:0% +transfer but what you really want is the + + + align:start position:0% +transfer but what you really want is the +rate constants for transfer so you have + + align:start position:0% +rate constants for transfer so you have + + + align:start position:0% +rate constants for transfer so you have +two questions is do you see transfer so + + align:start position:0% +two questions is do you see transfer so + + + align:start position:0% +two questions is do you see transfer so +that's the first question and so one + + align:start position:0% +that's the first question and so one + + + align:start position:0% +that's the first question and so one +could tell that by either of these two + + align:start position:0% +could tell that by either of these two + + + align:start position:0% +could tell that by either of these two +assays so you could use one and two and + + align:start position:0% +assays so you could use one and two and + + + align:start position:0% +assays so you could use one and two and +what you really want are the rate + + align:start position:0% +what you really want are the rate + + + align:start position:0% +what you really want are the rate +constants for transfer okay and the rate + + align:start position:0% +constants for transfer okay and the rate + + + align:start position:0% +constants for transfer okay and the rate +constants for transfer are dependent on + + align:start position:0% +constants for transfer are dependent on + + + align:start position:0% +constants for transfer are dependent on +the concentrations okay so how you set + + align:start position:0% +the concentrations okay so how you set + + + align:start position:0% +the concentrations okay so how you set +this up is something you've got to do a + + align:start position:0% +this up is something you've got to do a + + + align:start position:0% +this up is something you've got to do a +lot of messing around with and so if you + + align:start position:0% +lot of messing around with and so if you + + + align:start position:0% +lot of messing around with and so if you +look at this model you can ask the + + align:start position:0% +look at this model you can ask the + + + align:start position:0% +look at this model you can ask the +question how is this transfer occurred + + align:start position:0% +question how is this transfer occurred + + + align:start position:0% +question how is this transfer occurred +do you go through a ternary complex so + + align:start position:0% +do you go through a ternary complex so + + + align:start position:0% +do you go through a ternary complex so +does this form a complex with this and + + align:start position:0% +does this form a complex with this and + + + align:start position:0% +does this form a complex with this and +then the transfer occurs through the + + align:start position:0% +then the transfer occurs through the + + + align:start position:0% +then the transfer occurs through the +complex or you can ask a question does + + align:start position:0% +complex or you can ask a question does + + + align:start position:0% +complex or you can ask a question does +the Hien dissociate + + align:start position:0% +the Hien dissociate + + + align:start position:0% +the Hien dissociate +and then the heem get picked up so you + + align:start position:0% +and then the heem get picked up so you + + + align:start position:0% +and then the heem get picked up so you +can ask the question is what is the + + align:start position:0% +can ask the question is what is the + + + align:start position:0% +can ask the question is what is the +order of addition so you look and look + + align:start position:0% +order of addition so you look and look + + + align:start position:0% +order of addition so you look and look +at the mechanism of transfer and + + align:start position:0% + + + + align:start position:0% + +specifically the order of addition do + + align:start position:0% +specifically the order of addition do + + + align:start position:0% +specifically the order of addition do +you need the second protein there to see + + align:start position:0% +you need the second protein there to see + + + align:start position:0% +you need the second protein there to see +transfers so they've done a whole bunch + + align:start position:0% +transfers so they've done a whole bunch + + + align:start position:0% +transfers so they've done a whole bunch +of experiments like this I'll show you + + align:start position:0% +of experiments like this I'll show you + + + align:start position:0% +of experiments like this I'll show you +using I'll show you using the UM the + + align:start position:0% +using I'll show you using the UM the + + + align:start position:0% +using I'll show you using the UM the +sarey band what they they actually want + + align:start position:0% +sarey band what they they actually want + + + align:start position:0% +sarey band what they they actually want +it or in this particular reaction but + + align:start position:0% +it or in this particular reaction but + + + align:start position:0% +it or in this particular reaction but +they did a experiment where they just + + align:start position:0% +they did a experiment where they just + + + align:start position:0% +they did a experiment where they just +took is da is da loaded with him and + + align:start position:0% +took is da is da loaded with him and + + + align:start position:0% +took is da is da loaded with him and +asked the question does heme go in to + + align:start position:0% +asked the question does heme go in to + + + align:start position:0% +asked the question does heme go in to +solution okay so that's not a trivial + + align:start position:0% +solution okay so that's not a trivial + + + align:start position:0% +solution okay so that's not a trivial +experiment either because it can rebind + + align:start position:0% +experiment either because it can rebind + + + align:start position:0% +experiment either because it can rebind +it depends on the on rate and the off + + align:start position:0% +it depends on the on rate and the off + + + align:start position:0% +it depends on the on rate and the off +rate so you have to have a way of making + + align:start position:0% +rate so you have to have a way of making + + + align:start position:0% +rate so you have to have a way of making +sure that if it comes off you pull it to + + align:start position:0% +sure that if it comes off you pull it to + + + align:start position:0% +sure that if it comes off you pull it to +the right to be able to measure the rate + + align:start position:0% +the right to be able to measure the rate + + + align:start position:0% +the right to be able to measure the rate +constants so this whole problem is + + align:start position:0% +constants so this whole problem is + + + align:start position:0% +constants so this whole problem is +really associated with thinking about + + align:start position:0% +really associated with thinking about + + + align:start position:0% +really associated with thinking about +detailed kinetic models which I'm not + + align:start position:0% +detailed kinetic models which I'm not + + + align:start position:0% +detailed kinetic models which I'm not +gonna go into but if you look at the + + align:start position:0% +gonna go into but if you look at the + + + align:start position:0% +gonna go into but if you look at the +data that's what you need to think about + + align:start position:0% +data that's what you need to think about + + + align:start position:0% +data that's what you need to think about +to believe the data whether the data has + + align:start position:0% +to believe the data whether the data has + + + align:start position:0% +to believe the data whether the data has +been interpreted correctly that I'm very + + align:start position:0% +been interpreted correctly that I'm very + + + align:start position:0% +been interpreted correctly that I'm very +briefly going to show you need to derive + + align:start position:0% +briefly going to show you need to derive + + + align:start position:0% +briefly going to show you need to derive +the equations and look at what your + + align:start position:0% +the equations and look at what your + + + align:start position:0% +the equations and look at what your +expectations are are they consistent + + align:start position:0% +expectations are are they consistent + + + align:start position:0% +expectations are are they consistent +with a kinetic analysis of what's going + + align:start position:0% +with a kinetic analysis of what's going + + + align:start position:0% +with a kinetic analysis of what's going +on so here they see a rate constant so + + align:start position:0% +on so here they see a rate constant so + + + align:start position:0% +on so here they see a rate constant so +here they're just looking simply at this + + align:start position:0% +here they're just looking simply at this + + + align:start position:0% +here they're just looking simply at this +reaction does this go to i SD a a po + + + align:start position:0% +reaction does this go to i SD a a po + + + + align:start position:0% +reaction does this go to i SD a a po + +heme okay and if they look at that rate + + align:start position:0% +heme okay and if they look at that rate + + + align:start position:0% +heme okay and if they look at that rate +constant is 0.07 per second okay so it's + + align:start position:0% +constant is 0.07 per second okay so it's + + + align:start position:0% +constant is 0.07 per second okay so it's +really slow okay so then the question is + + align:start position:0% +really slow okay so then the question is + + + align:start position:0% +really slow okay so then the question is +is this transfer D does anybody remember + + align:start position:0% +is this transfer D does anybody remember + + + align:start position:0% +is this transfer D does anybody remember +what the rate constants were for + + align:start position:0% +what the rate constants were for + + + align:start position:0% +what the rate constants were for +transfer in the problem you worked at + + align:start position:0% +transfer in the problem you worked at + + + align:start position:0% +transfer in the problem you worked at +who is it seconds was it minutes did you + + align:start position:0% +who is it seconds was it minutes did you + + + align:start position:0% +who is it seconds was it minutes did you +think about it I don't remember what the + + align:start position:0% +think about it I don't remember what the + + + align:start position:0% +think about it I don't remember what the +numbers are at the top + + align:start position:0% +numbers are at the top + + + align:start position:0% +numbers are at the top +yeah so that's much faster than this and + + align:start position:0% +yeah so that's much faster than this and + + + align:start position:0% +yeah so that's much faster than this and +so this is a really low number but the + + align:start position:0% +so this is a really low number but the + + + align:start position:0% +so this is a really low number but the +question is how remember we're missing + + align:start position:0% +question is how remember we're missing + + + align:start position:0% +question is how remember we're missing +part of the whole system and so could be + + align:start position:0% +part of the whole system and so could be + + + align:start position:0% +part of the whole system and so could be +really low just because we don't have + + align:start position:0% +really low just because we don't have + + + align:start position:0% +really low just because we don't have +the system set up to be to mimic what we + + align:start position:0% +the system set up to be to mimic what we + + + align:start position:0% +the system set up to be to mimic what we +see in the native organism so that's the + + align:start position:0% +see in the native organism so that's the + + + align:start position:0% +see in the native organism so that's the +problem you always face and so if you + + align:start position:0% +problem you always face and so if you + + + align:start position:0% +problem you always face and so if you +look at the data here's what they're + + align:start position:0% +look at the data here's what they're + + + align:start position:0% +look at the data here's what they're +monitoring so here's the soiree band at + + align:start position:0% +monitoring so here's the soiree band at + + + align:start position:0% +monitoring so here's the soiree band at +400 and so you need to get a good + + align:start position:0% +400 and so you need to get a good + + + align:start position:0% +400 and so you need to get a good +spectrum and convince yourself you're + + align:start position:0% +spectrum and convince yourself you're + + + align:start position:0% +spectrum and convince yourself you're +looking at the stoichiometric loading so + + align:start position:0% +looking at the stoichiometric loading so + + + align:start position:0% +looking at the stoichiometric loading so +you need to know how much he may it's + + align:start position:0% +you need to know how much he may it's + + + align:start position:0% +you need to know how much he may it's +going to affect your absorption spectrum + + align:start position:0% +going to affect your absorption spectrum + + + align:start position:0% +going to affect your absorption spectrum +okay so you need to know how much is + + align:start position:0% +okay so you need to know how much is + + + align:start position:0% +okay so you need to know how much is +loaded and then you could do the + + align:start position:0% +loaded and then you could do the + + + align:start position:0% +loaded and then you could do the +experiment outlined over there and what + + align:start position:0% +experiment outlined over there and what + + + align:start position:0% +experiment outlined over there and what +they're monitoring is these small + + align:start position:0% +they're monitoring is these small + + + align:start position:0% +they're monitoring is these small +changes okay + + align:start position:0% +changes okay + + + align:start position:0% +changes okay +and so when they do that they come up + + align:start position:0% +and so when they do that they come up + + + align:start position:0% +and so when they do that they come up +with if you look at the analysis and + + align:start position:0% +with if you look at the analysis and + + + align:start position:0% +with if you look at the analysis and +I'll show you a few pieces of data they + + align:start position:0% +I'll show you a few pieces of data they + + + align:start position:0% +I'll show you a few pieces of data they +come up with them they favor the model + + align:start position:0% +come up with them they favor the model + + + align:start position:0% +come up with them they favor the model +associated with the kinetic analysis of + + align:start position:0% +associated with the kinetic analysis of + + + align:start position:0% +associated with the kinetic analysis of +all of their data that you form a + + align:start position:0% +all of their data that you form a + + + align:start position:0% +all of their data that you form a +tertiary complex sorry a binary complex + + align:start position:0% +tertiary complex sorry a binary complex + + + align:start position:0% +tertiary complex sorry a binary complex +of the two proteins and that the heme is + + align:start position:0% +of the two proteins and that the heme is + + + align:start position:0% +of the two proteins and that the heme is +transferred from one to the other and + + align:start position:0% +transferred from one to the other and + + + align:start position:0% +transferred from one to the other and +then the a PO is da dissociates okay so + + align:start position:0% +then the a PO is da dissociates okay so + + + align:start position:0% +then the a PO is da dissociates okay so +this is analogous to what you've seen + + align:start position:0% +this is analogous to what you've seen + + + align:start position:0% +this is analogous to what you've seen +and here's some data so they've done it + + align:start position:0% +and here's some data so they've done it + + + align:start position:0% +and here's some data so they've done it +with every single pair in this + + align:start position:0% +with every single pair in this + + + align:start position:0% +with every single pair in this +particular paper and what you can go do + + align:start position:0% +particular paper and what you can go do + + + align:start position:0% +particular paper and what you can go do +what you can do and they've done all the + + align:start position:0% +what you can do and they've done all the + + + align:start position:0% +what you can do and they've done all the +experiments the same way I've been able + + align:start position:0% +experiments the same way I've been able + + + align:start position:0% +experiments the same way I've been able +to see differences and so array bands + + align:start position:0% +to see differences and so array bands + + + align:start position:0% +to see differences and so array bands +these were all done with changes in the + + align:start position:0% +these were all done with changes in the + + + align:start position:0% +these were all done with changes in the +spectra the visible spectra but if you + + align:start position:0% +spectra the visible spectra but if you + + + align:start position:0% +spectra the visible spectra but if you +look at this for example from the + + align:start position:0% +look at this for example from the + + + align:start position:0% +look at this for example from the +transfer of the heme from met hemoglobin + + align:start position:0% +transfer of the heme from met hemoglobin + + + align:start position:0% +transfer of the heme from met hemoglobin +okay so that's the first step up here + + align:start position:0% +okay so that's the first step up here + + + align:start position:0% +okay so that's the first step up here +and you look at all the rate constants + + align:start position:0% +and you look at all the rate constants + + + align:start position:0% +and you look at all the rate constants +they measured they the fastest number is + + align:start position:0% +they measured they the fastest number is + + + align:start position:0% +they measured they the fastest number is +zero point three one per second okay so + + align:start position:0% +zero point three one per second okay so + + + align:start position:0% +zero point three one per second okay so +that's slow but you might expect it + + align:start position:0% +that's slow but you might expect it + + + align:start position:0% +that's slow but you might expect it +might not be so easy to extract the heme + + align:start position:0% +might not be so easy to extract the heme + + + align:start position:0% +might not be so easy to extract the heme +of hemoglobin okay so what you might + + align:start position:0% +of hemoglobin okay so what you might + + + align:start position:0% +of hemoglobin okay so what you might +expect this to be slow but again if you + + align:start position:0% +expect this to be slow but again if you + + + align:start position:0% +expect this to be slow but again if you +look here and this is the thing that + + align:start position:0% +look here and this is the thing that + + + align:start position:0% +look here and this is the thing that +I think hopefully some of you thought + + align:start position:0% +I think hopefully some of you thought + + + align:start position:0% +I think hopefully some of you thought +about if you look at the rate constants + + align:start position:0% +about if you look at the rate constants + + + align:start position:0% +about if you look at the rate constants +these reactions are all by molecular + + align:start position:0% +these reactions are all by molecular + + + align:start position:0% +these reactions are all by molecular +okay but what do they have up there they + + align:start position:0% +okay but what do they have up there they + + + align:start position:0% +okay but what do they have up there they +have first-order processes so that has + + align:start position:0% +have first-order processes so that has + + + align:start position:0% +have first-order processes so that has +got to be telling you something about + + align:start position:0% +got to be telling you something about + + + align:start position:0% +got to be telling you something about +the interaction let's compare whether + + align:start position:0% +the interaction let's compare whether + + + align:start position:0% +the interaction let's compare whether +this interaction is rapid and reversible + + align:start position:0% +this interaction is rapid and reversible + + + align:start position:0% +this interaction is rapid and reversible +okay and in the paper describing this + + align:start position:0% +okay and in the paper describing this + + + align:start position:0% +okay and in the paper describing this +work in detail and I give you the + + align:start position:0% +work in detail and I give you the + + + align:start position:0% +work in detail and I give you the +reference in the PowerPoint for those if + + align:start position:0% +reference in the PowerPoint for those if + + + align:start position:0% +reference in the PowerPoint for those if +you want to look at it you need to think + + align:start position:0% +you want to look at it you need to think + + + align:start position:0% +you want to look at it you need to think +about the kinetic analysis so when + + align:start position:0% +about the kinetic analysis so when + + + align:start position:0% +about the kinetic analysis so when +you're looking at rate constants you + + align:start position:0% +you're looking at rate constants you + + + align:start position:0% +you're looking at rate constants you +need to think about whether it's first + + align:start position:0% +need to think about whether it's first + + + align:start position:0% +need to think about whether it's first +or second order or somehow they have to + + align:start position:0% +or second order or somehow they have to + + + align:start position:0% +or second order or somehow they have to +get together if this is due when it + + align:start position:0% +get together if this is due when it + + + align:start position:0% +get together if this is due when it +happened rapid and reversible you still + + align:start position:0% +happened rapid and reversible you still + + + align:start position:0% +happened rapid and reversible you still +have a term for that equilibrium step + + align:start position:0% +have a term for that equilibrium step + + + align:start position:0% +have a term for that equilibrium step +but then you're looking at a first order + + align:start position:0% +but then you're looking at a first order + + + align:start position:0% +but then you're looking at a first order +process okay + + align:start position:0% +process okay + + + align:start position:0% +process okay +so if you look I'm not going to go + + align:start position:0% +so if you look I'm not going to go + + + align:start position:0% +so if you look I'm not going to go +through the whole thing but if you look + + align:start position:0% +through the whole thing but if you look + + + align:start position:0% +through the whole thing but if you look +at the transfer from hollo is DB so + + align:start position:0% +at the transfer from hollo is DB so + + + align:start position:0% +at the transfer from hollo is DB so +that's the second step it got the B got + + align:start position:0% +that's the second step it got the B got + + + align:start position:0% +that's the second step it got the B got +the heme out of the hemoglobin and then + + align:start position:0% +the heme out of the hemoglobin and then + + + align:start position:0% +the heme out of the hemoglobin and then +you can look at the transfer to all the + + align:start position:0% +you can look at the transfer to all the + + + align:start position:0% +you can look at the transfer to all the +other proteins you see that in this case + + align:start position:0% +other proteins you see that in this case + + + align:start position:0% +other proteins you see that in this case +one is 114 per second so that's a fast + + align:start position:0% +one is 114 per second so that's a fast + + + align:start position:0% +one is 114 per second so that's a fast +transfer okay so you can look down + + align:start position:0% +transfer okay so you can look down + + + align:start position:0% +transfer okay so you can look down +they've done every single one of these + + align:start position:0% +they've done every single one of these + + + align:start position:0% +they've done every single one of these +steps and they've also then also asked + + align:start position:0% +steps and they've also then also asked + + + align:start position:0% +steps and they've also then also asked +the question 10 these proteins have + + align:start position:0% +the question 10 these proteins have + + + align:start position:0% +the question 10 these proteins have +catalytically so then they put in a + + align:start position:0% +catalytically so then they put in a + + + align:start position:0% +catalytically so then they put in a +small amount of one and look at the rate + + align:start position:0% +small amount of one and look at the rate + + + align:start position:0% +small amount of one and look at the rate +constants in the presence of the absence + + align:start position:0% +constants in the presence of the absence + + + align:start position:0% +constants in the presence of the absence +of one and they conclude that these + + align:start position:0% +of one and they conclude that these + + + align:start position:0% +of one and they conclude that these +proteins can act catalytically as well + + align:start position:0% +proteins can act catalytically as well + + + align:start position:0% +proteins can act catalytically as well +so these are the kinds I don't want to + + align:start position:0% +so these are the kinds I don't want to + + + align:start position:0% +so these are the kinds I don't want to +spend a lot of time discussing this + + align:start position:0% +spend a lot of time discussing this + + + align:start position:0% +spend a lot of time discussing this +detailed set up because I think you + + align:start position:0% +detailed set up because I think you + + + align:start position:0% +detailed set up because I think you +still have to worry about being + + align:start position:0% +still have to worry about being + + + align:start position:0% +still have to worry about being +covalently attached to the peptidoglycan + + align:start position:0% +covalently attached to the peptidoglycan + + + align:start position:0% +covalently attached to the peptidoglycan +but these rate constants are pretty darn + + align:start position:0% +but these rate constants are pretty darn + + + align:start position:0% +but these rate constants are pretty darn +fast okay and so then the other thing + + align:start position:0% +fast okay and so then the other thing + + + align:start position:0% +fast okay and so then the other thing +that's interesting is why does it have + + align:start position:0% +that's interesting is why does it have + + + align:start position:0% +that's interesting is why does it have +an order does it have an order so if you + + align:start position:0% +an order does it have an order so if you + + + align:start position:0% +an order does it have an order so if you +were going to take B can I transfer it + + align:start position:0% +were going to take B can I transfer it + + + align:start position:0% +were going to take B can I transfer it +to C and what are the differences in the + + align:start position:0% +to C and what are the differences in the + + + align:start position:0% +to C and what are the differences in the +rate constants and here it's 114 versus + + align:start position:0% +rate constants and here it's 114 versus + + + align:start position:0% +rate constants and here it's 114 versus +15 okay so now the question is did they + + align:start position:0% +15 okay so now the question is did they + + + align:start position:0% +15 okay so now the question is did they +set up the experiment correctly you know + + align:start position:0% +set up the experiment correctly you know + + + align:start position:0% +set up the experiment correctly you know +they probably used all the same constant + + align:start position:0% +they probably used all the same constant + + + align:start position:0% +they probably used all the same constant +trations in the experiment but one might + + align:start position:0% +trations in the experiment but one might + + + align:start position:0% +trations in the experiment but one might +have an higher affinity than the other + + align:start position:0% +have an higher affinity than the other + + + align:start position:0% +have an higher affinity than the other +and so you need to take you need to + + align:start position:0% +and so you need to take you need to + + + align:start position:0% +and so you need to take you need to +think about all that stuff and if they + + align:start position:0% +think about all that stuff and if they + + + align:start position:0% +think about all that stuff and if they +thought about that correctly they really + + align:start position:0% +thought about that correctly they really + + + align:start position:0% +thought about that correctly they really +have learned something about the order + + align:start position:0% +have learned something about the order + + + align:start position:0% +have learned something about the order +of addition and the ability of these + + align:start position:0% +of addition and the ability of these + + + align:start position:0% +of addition and the ability of these +proteins to act catalytically so this is + + align:start position:0% +proteins to act catalytically so this is + + + align:start position:0% +proteins to act catalytically so this is +a way this is state-of-the-art right now + + align:start position:0% +a way this is state-of-the-art right now + + + align:start position:0% +a way this is state-of-the-art right now +the way people are studying this and + + align:start position:0% +the way people are studying this and + + + align:start position:0% +the way people are studying this and +this kinetic mod the kinetic data has + + align:start position:0% +this kinetic mod the kinetic data has + + + align:start position:0% +this kinetic mod the kinetic data has +allowed us to come up with that model I + + align:start position:0% +allowed us to come up with that model I + + + align:start position:0% +allowed us to come up with that model I +just showed you that there is an ordered + + align:start position:0% +just showed you that there is an ordered + + + align:start position:0% +just showed you that there is an ordered +way to transfer these systems and then I + + align:start position:0% +way to transfer these systems and then I + + + align:start position:0% +way to transfer these systems and then I +just want to say very briefly I just + + align:start position:0% +just want to say very briefly I just + + + align:start position:0% +just want to say very briefly I just +want to show you very briefly the + + align:start position:0% +want to show you very briefly the + + + align:start position:0% +want to show you very briefly the +structures of these and just show you + + align:start position:0% +structures of these and just show you + + + align:start position:0% +structures of these and just show you +with again where the state of the art is + + align:start position:0% +with again where the state of the art is + + + align:start position:0% +with again where the state of the art is +in this area all of these neat domains + + align:start position:0% +in this area all of these neat domains + + + align:start position:0% +in this area all of these neat domains +so neat domains are the heme binding + + align:start position:0% +so neat domains are the heme binding + + + align:start position:0% +so neat domains are the heme binding +domains 120 amino acids they're found in + + align:start position:0% +domains 120 amino acids they're found in + + + align:start position:0% +domains 120 amino acids they're found in +a b c and h they found in four different + + align:start position:0% +a b c and h they found in four different + + + align:start position:0% +a b c and h they found in four different +proteins okay they all this is + + align:start position:0% +proteins okay they all this is + + + align:start position:0% +proteins okay they all this is +superposition of all the neat domains + + align:start position:0% +superposition of all the neat domains + + + align:start position:0% +superposition of all the neat domains +you can see they all look alike okay + + align:start position:0% +you can see they all look alike okay + + + align:start position:0% +you can see they all look alike okay +furthermore if you go down here and you + + align:start position:0% +furthermore if you go down here and you + + + align:start position:0% +furthermore if you go down here and you +look at binding they all have a Penta + + align:start position:0% +look at binding they all have a Penta + + + align:start position:0% +look at binding they all have a Penta +coordinate heme with one axial again + + align:start position:0% +coordinate heme with one axial again + + + align:start position:0% +coordinate heme with one axial again +being a tyrosine the other one the top + + align:start position:0% +being a tyrosine the other one the top + + + align:start position:0% +being a tyrosine the other one the top +face is a PO and in this version of it + + align:start position:0% +face is a PO and in this version of it + + + align:start position:0% +face is a PO and in this version of it +so they also have a structure of two of + + align:start position:0% +so they also have a structure of two of + + + align:start position:0% +so they also have a structure of two of +these things bound together + + align:start position:0% +these things bound together + + + align:start position:0% +these things bound together +all right again these are little domains + + align:start position:0% +all right again these are little domains + + + align:start position:0% +all right again these are little domains +and so the question that you have to ask + + align:start position:0% +and so the question that you have to ask + + + align:start position:0% +and so the question that you have to ask +yourself which is this question of + + align:start position:0% +yourself which is this question of + + + align:start position:0% +yourself which is this question of +ligand rates of exchange of ligands how + + align:start position:0% +ligand rates of exchange of ligands how + + + align:start position:0% +ligand rates of exchange of ligands how +is this transferred do you have how how + + align:start position:0% +is this transferred do you have how how + + + align:start position:0% +is this transferred do you have how how +does this interface help this guy move + + align:start position:0% +does this interface help this guy move + + + align:start position:0% +does this interface help this guy move +from this protein to that protein and + + align:start position:0% +from this protein to that protein and + + + align:start position:0% +from this protein to that protein and +that's what people are focusing their + + align:start position:0% +that's what people are focusing their + + + align:start position:0% +that's what people are focusing their +energies on trying to think about the + + align:start position:0% +energies on trying to think about the + + + align:start position:0% +energies on trying to think about the +detailed structures to come up with a + + align:start position:0% +detailed structures to come up with a + + + align:start position:0% +detailed structures to come up with a +model for how this transfer occurs and + + align:start position:0% +model for how this transfer occurs and + + + align:start position:0% +model for how this transfer occurs and +I'll just show you this is a if you go + + align:start position:0% +I'll just show you this is a if you go + + + align:start position:0% +I'll just show you this is a if you go +all the way down you're going from C + + align:start position:0% +all the way down you're going from C + + + align:start position:0% +all the way down you're going from C +you're going to go from C to e e has a + + align:start position:0% +you're going to go from C to e e has a + + + align:start position:0% +you're going to go from C to e e has a +different structure so the mechanism of + + align:start position:0% +different structure so the mechanism of + + + align:start position:0% +different structure so the mechanism of +heat transfer is different people have a + + align:start position:0% +heat transfer is different people have a + + + align:start position:0% +heat transfer is different people have a +model for that you need to think about + + align:start position:0% +model for that you need to think about + + + align:start position:0% +model for that you need to think about +the details and now furthermore + + align:start position:0% +the details and now furthermore + + + align:start position:0% +the details and now furthermore +you can go from E to F all the way + + align:start position:0% +you can go from E to F all the way + + + align:start position:0% +you can go from E to F all the way +through the plasma membrane to the + + align:start position:0% +through the plasma membrane to the + + + align:start position:0% +through the plasma membrane to the +ATPase which then helped you get the + + align:start position:0% +ATPase which then helped you get the + + + align:start position:0% +ATPase which then helped you get the +heme provides the driving force getting + + align:start position:0% +heme provides the driving force getting + + + align:start position:0% +heme provides the driving force getting +him into the into the cytosol so we have + + align:start position:0% +him into the into the cytosol so we have + + + align:start position:0% +him into the into the cytosol so we have +a lot of structural data but what's + + align:start position:0% +a lot of structural data but what's + + + align:start position:0% +a lot of structural data but what's +disappointing I think from reading those + + align:start position:0% +disappointing I think from reading those + + + align:start position:0% +disappointing I think from reading those +papers which I have read is we still + + align:start position:0% +papers which I have read is we still + + + align:start position:0% +papers which I have read is we still +really don't have a good model for how + + align:start position:0% +really don't have a good model for how + + + align:start position:0% +really don't have a good model for how +these transfers actually work so this is + + align:start position:0% +these transfers actually work so this is + + + align:start position:0% +these transfers actually work so this is +an active area of research research and + + align:start position:0% +an active area of research research and + + + align:start position:0% +an active area of research research and +the people interested in the + + align:start position:0% +the people interested in the + + + align:start position:0% +the people interested in the +bioinorganic chemistry and how you get + + align:start position:0% +bioinorganic chemistry and how you get + + + align:start position:0% +bioinorganic chemistry and how you get +heme into cells okay so that is the end + + align:start position:0% +heme into cells okay so that is the end + + + align:start position:0% +heme into cells okay so that is the end +of module 6 I think we've learned a lot + + align:start position:0% +of module 6 I think we've learned a lot + + + align:start position:0% +of module 6 I think we've learned a lot +in the last few years about these + + align:start position:0% +in the last few years about these + + + align:start position:0% +in the last few years about these +proteins but as you can see we still + + align:start position:0% +proteins but as you can see we still + + + align:start position:0% +proteins but as you can see we still +have a long way to go in terms of + + align:start position:0% +have a long way to go in terms of + + + align:start position:0% +have a long way to go in terms of +molecular understanding okay and so the + + align:start position:0% +molecular understanding okay and so the + + + align:start position:0% +molecular understanding okay and so the +next module module cell 7 is going to be + + align:start position:0% +next module module cell 7 is going to be + + + align:start position:0% +next module module cell 7 is going to be +the shortest module and I'll give you an + + align:start position:0% +the shortest module and I'll give you an + + + align:start position:0% +the shortest module and I'll give you an +outline of what I'm going to be what I'm + + align:start position:0% +outline of what I'm going to be what I'm + + + align:start position:0% +outline of what I'm going to be what I'm +gonna be and then today's the first + + align:start position:0% +gonna be and then today's the first + + + align:start position:0% +gonna be and then today's the first +lecture is much longer than the second + + align:start position:0% +lecture is much longer than the second + + + align:start position:0% +lecture is much longer than the second +lecture and we'll see the second lecture + + align:start position:0% +lecture and we'll see the second lecture + + + align:start position:0% +lecture and we'll see the second lecture +is going to be focused a lot on what + + align:start position:0% +is going to be focused a lot on what + + + align:start position:0% +is going to be focused a lot on what +we're doing in recitation this week so + + align:start position:0% +we're doing in recitation this week so + + + align:start position:0% +we're doing in recitation this week so +if you notice maybe you you haven't but + + align:start position:0% +if you notice maybe you you haven't but + + + align:start position:0% +if you notice maybe you you haven't but +we posted the readings and one of the + + align:start position:0% +we posted the readings and one of the + + + align:start position:0% +we posted the readings and one of the +papers for the course this part of the + + align:start position:0% +papers for the course this part of the + + + align:start position:0% +papers for the course this part of the +course the lecture part of the course is + + align:start position:0% +course the lecture part of the course is + + + align:start position:0% +course the lecture part of the course is +a Carroll paper you're supposed to read + + align:start position:0% +a Carroll paper you're supposed to read + + + align:start position:0% +a Carroll paper you're supposed to read +for recitation so there's a lot of + + align:start position:0% +for recitation so there's a lot of + + + align:start position:0% +for recitation so there's a lot of +overlap and so the second lecture will + + align:start position:0% +overlap and so the second lecture will + + + align:start position:0% +overlap and so the second lecture will +be much shorter because we're going to + + align:start position:0% +be much shorter because we're going to + + + align:start position:0% +be much shorter because we're going to +draw on what we're doing in recitation + + align:start position:0% +draw on what we're doing in recitation + + + align:start position:0% +draw on what we're doing in recitation +actually today so okay so let me give + + align:start position:0% +actually today so okay so let me give + + + align:start position:0% +actually today so okay so let me give +you the outline so module 7 ok is a + + align:start position:0% +you the outline so module 7 ok is a + + + align:start position:0% +you the outline so module 7 ok is a +shortest and this is the required + + align:start position:0% +shortest and this is the required + + + align:start position:0% +shortest and this is the required +reading so we posted a review article by + + align:start position:0% +reading so we posted a review article by + + + align:start position:0% +reading so we posted a review article by +Winterbourne who in my opinion this area + + align:start position:0% +Winterbourne who in my opinion this area + + + align:start position:0% +Winterbourne who in my opinion this area +of rare reactive oxygen species and how + + align:start position:0% +of rare reactive oxygen species and how + + + align:start position:0% +of rare reactive oxygen species and how +romeo's to how you control reactive + + align:start position:0% +romeo's to how you control reactive + + + align:start position:0% +romeo's to how you control reactive +oxygen species I'm going to show + + align:start position:0% +oxygen species I'm going to show + + + align:start position:0% +oxygen species I'm going to show +they could be good they can be bad just + + align:start position:0% +they could be good they can be bad just + + + align:start position:0% +they could be good they can be bad just +like we saw with iron it's all a + + align:start position:0% +like we saw with iron it's all a + + + align:start position:0% +like we saw with iron it's all a +question of homeostasis the most cycles + + align:start position:0% +question of homeostasis the most cycles + + + align:start position:0% +question of homeostasis the most cycles +the most thoughtful discussions have + + align:start position:0% +the most thoughtful discussions have + + + align:start position:0% +the most thoughtful discussions have +been described by Winterbourne who is in + + align:start position:0% +been described by Winterbourne who is in + + + align:start position:0% +been described by Winterbourne who is in +New Zealand who really thinks about the + + align:start position:0% +New Zealand who really thinks about the + + + align:start position:0% +New Zealand who really thinks about the +kinetics of what's going on and I would + + align:start position:0% +kinetics of what's going on and I would + + + align:start position:0% +kinetics of what's going on and I would +argue you can't do anything in this + + align:start position:0% +argue you can't do anything in this + + + align:start position:0% +argue you can't do anything in this +field without thinking about kinetics + + align:start position:0% +field without thinking about kinetics + + + align:start position:0% +field without thinking about kinetics +which most people most MDS in this field + + align:start position:0% +which most people most MDS in this field + + + align:start position:0% +which most people most MDS in this field +don't think about it all okay so the + + align:start position:0% +don't think about it all okay so the + + + align:start position:0% +don't think about it all okay so the +literature is a mess okay and so but I + + align:start position:0% +literature is a mess okay and so but I + + + align:start position:0% +literature is a mess okay and so but I +think the last few years it's become + + align:start position:0% +think the last few years it's become + + + align:start position:0% +think the last few years it's become +it's become it's starting to get my + + align:start position:0% +it's become it's starting to get my + + + align:start position:0% +it's become it's starting to get my +money okay and I think it's an + + align:start position:0% +money okay and I think it's an + + + align:start position:0% +money okay and I think it's an +incredibly important area I guarantee + + align:start position:0% +incredibly important area I guarantee + + + align:start position:0% +incredibly important area I guarantee +you that that's true so unmod an + + align:start position:0% +you that that's true so unmod an + + + align:start position:0% +you that that's true so unmod an +incredibly important the area is going + + align:start position:0% +incredibly important the area is going + + + align:start position:0% +incredibly important the area is going +to be up to you guys but I think it's + + align:start position:0% +to be up to you guys but I think it's + + + align:start position:0% +to be up to you guys but I think it's +going to happen in the next five years + + align:start position:0% +going to happen in the next five years + + + align:start position:0% +going to happen in the next five years +or something I think we're gonna we've + + align:start position:0% +or something I think we're gonna we've + + + align:start position:0% +or something I think we're gonna we've +already learned a lot in the last couple + + align:start position:0% +already learned a lot in the last couple + + + align:start position:0% +already learned a lot in the last couple +of years so I'm gonna have an outline so + + align:start position:0% +of years so I'm gonna have an outline so + + + align:start position:0% +of years so I'm gonna have an outline so +we have that paper and then we have the + + align:start position:0% +we have that paper and then we have the + + + align:start position:0% +we have that paper and then we have the +Carroll paper that you guys hopefully + + align:start position:0% +Carroll paper that you guys hopefully + + + align:start position:0% +Carroll paper that you guys hopefully +have already looked at in some form all + + align:start position:0% +have already looked at in some form all + + + align:start position:0% +have already looked at in some form all +right so here I need to switch okay so + + align:start position:0% +right so here I need to switch okay so + + + align:start position:0% +right so here I need to switch okay so +where are we going and so we're gonna + + align:start position:0% +where are we going and so we're gonna + + + align:start position:0% +where are we going and so we're gonna +have a couple of lectures first of all + + align:start position:0% +have a couple of lectures first of all + + + align:start position:0% +have a couple of lectures first of all +what is our OS so our OS our reactive + + align:start position:0% +what is our OS so our OS our reactive + + + align:start position:0% +what is our OS so our OS our reactive +oxygen species + + align:start position:0% + + + + align:start position:0% + +okay so automatically they're a bunch of + + align:start position:0% +okay so automatically they're a bunch of + + + align:start position:0% +okay so automatically they're a bunch of +molecules that are reactive and so what + + align:start position:0% +molecules that are reactive and so what + + + align:start position:0% +molecules that are reactive and so what +you need to think about is what is + + align:start position:0% +you need to think about is what is + + + align:start position:0% +you need to think about is what is +reactive me okay so the first thing is + + align:start position:0% +reactive me okay so the first thing is + + + align:start position:0% +reactive me okay so the first thing is +we're going to identify them okay the + + align:start position:0% +we're going to identify them okay the + + + align:start position:0% +we're going to identify them okay the +second thing is we're going to look at + + align:start position:0% +second thing is we're going to look at + + + align:start position:0% +second thing is we're going to look at +the chemical reactivity and again the + + align:start position:0% +the chemical reactivity and again the + + + align:start position:0% +the chemical reactivity and again the +question of chemical reactivity can be + + align:start position:0% +question of chemical reactivity can be + + + align:start position:0% +question of chemical reactivity can be +quite complex but I'm going to give you + + align:start position:0% +quite complex but I'm going to give you + + + align:start position:0% +quite complex but I'm going to give you +my view of the chemical reactivity and + + align:start position:0% +my view of the chemical reactivity and + + + align:start position:0% +my view of the chemical reactivity and +what that view is based on and then + + align:start position:0% +what that view is based on and then + + + align:start position:0% +what that view is based on and then +we'll very briefly look at over since we + + align:start position:0% +we'll very briefly look at over since we + + + align:start position:0% +we'll very briefly look at over since we +move + + align:start position:0% +move + + + align:start position:0% +move +an anaerobic world whatever a billion + + align:start position:0% +an anaerobic world whatever a billion + + + align:start position:0% +an anaerobic world whatever a billion +years ago into anaerobic world like we + + align:start position:0% +years ago into anaerobic world like we + + + align:start position:0% +years ago into anaerobic world like we +learned from the last module the + + align:start position:0% +learned from the last module the + + + align:start position:0% +learned from the last module the +question is how do we defend ourselves + + align:start position:0% +question is how do we defend ourselves + + + align:start position:0% +question is how do we defend ourselves +against the presence of oxygen with + + align:start position:0% +against the presence of oxygen with + + + align:start position:0% +against the presence of oxygen with +reduced metals okay and that's the issue + + align:start position:0% +reduced metals okay and that's the issue + + + align:start position:0% +reduced metals okay and that's the issue +we raised last time so what are our + + align:start position:0% +we raised last time so what are our + + + align:start position:0% +we raised last time so what are our +defense mechanisms because we saw we had + + align:start position:0% +defense mechanisms because we saw we had + + + align:start position:0% +defense mechanisms because we saw we had +copper we had iron and now we have + + align:start position:0% +copper we had iron and now we have + + + align:start position:0% +copper we had iron and now we have +oxygen and we'll see that that can be a + + align:start position:0% +oxygen and we'll see that that can be a + + + align:start position:0% +oxygen and we'll see that that can be a +recipe for disaster and once you can + + align:start position:0% +recipe for disaster and once you can + + + align:start position:0% +recipe for disaster and once you can +figure out how to control all of that so + + align:start position:0% +figure out how to control all of that so + + + align:start position:0% +figure out how to control all of that so +again it's all homeostasis so that's the + + align:start position:0% +again it's all homeostasis so that's the + + + align:start position:0% +again it's all homeostasis so that's the +second that will be the first part of + + align:start position:0% +second that will be the first part of + + + align:start position:0% +second that will be the first part of +today's lecture then we're going to move + + align:start position:0% +today's lecture then we're going to move + + + align:start position:0% +today's lecture then we're going to move +into the question of the battle between + + align:start position:0% + + + + align:start position:0% + +bacteria or viruses or parasites in + + align:start position:0% +bacteria or viruses or parasites in + + + align:start position:0% +bacteria or viruses or parasites in +humans and what I'm going to talk about + + align:start position:0% +humans and what I'm going to talk about + + + align:start position:0% +humans and what I'm going to talk about +specifically is destruction of bacteria + + align:start position:0% +specifically is destruction of bacteria + + + align:start position:0% +specifically is destruction of bacteria +by neutrophils and we'll see that + + align:start position:0% +by neutrophils and we'll see that + + + align:start position:0% +by neutrophils and we'll see that +neutrophils are white blood cells and we + + align:start position:0% +neutrophils are white blood cells and we + + + align:start position:0% +neutrophils are white blood cells and we +will see that they're the first + + align:start position:0% +will see that they're the first + + + align:start position:0% +will see that they're the first +responders so if you have a bacteria and + + align:start position:0% +responders so if you have a bacteria and + + + align:start position:0% +responders so if you have a bacteria and +our blood stream the first guys they are + + align:start position:0% +our blood stream the first guys they are + + + align:start position:0% +our blood stream the first guys they are +the neutrophils and that's what we're + + align:start position:0% +the neutrophils and that's what we're + + + align:start position:0% +the neutrophils and that's what we're +gonna focus on okay so let me see + + align:start position:0% +gonna focus on okay so let me see + + + align:start position:0% +gonna focus on okay so let me see +alright I'll go over here + + align:start position:0% + + + + align:start position:0% + +okay so neutrophils are the first + + align:start position:0% +okay so neutrophils are the first + + + align:start position:0% +okay so neutrophils are the first +responders and all we know quite a bit + + align:start position:0% +responders and all we know quite a bit + + + align:start position:0% +responders and all we know quite a bit +about this and really what we're going + + align:start position:0% +about this and really what we're going + + + align:start position:0% +about this and really what we're going +to be focusing on and both today's + + align:start position:0% +to be focusing on and both today's + + + align:start position:0% +to be focusing on and both today's +lecture and in the next lecture is one + + align:start position:0% +lecture and in the next lecture is one + + + align:start position:0% +lecture and in the next lecture is one +prote the group of isozymes called knox + + align:start position:0% +prote the group of isozymes called knox + + + align:start position:0% +prote the group of isozymes called knox +proteins and o-x NADPH oxidase --is and + + align:start position:0% + + + + align:start position:0% + +okay we're going to talk about that + + align:start position:0% +okay we're going to talk about that + + + align:start position:0% +okay we're going to talk about that +particular protein and we're going to be + + align:start position:0% +particular protein and we're going to be + + + align:start position:0% +particular protein and we're going to be +specifically focused on Knox two and + + align:start position:0% +specifically focused on Knox two and + + + align:start position:0% +specifically focused on Knox two and +we'll see that Knox twos professional + + align:start position:0% +we'll see that Knox twos professional + + + align:start position:0% +we'll see that Knox twos professional +job we'll talk about that is to generate + + align:start position:0% +job we'll talk about that is to generate + + + align:start position:0% +job we'll talk about that is to generate +a reactive oxygen species superoxide + + align:start position:0% +a reactive oxygen species superoxide + + + align:start position:0% +a reactive oxygen species superoxide +which is then going to be used in some + + align:start position:0% +which is then going to be used in some + + + align:start position:0% +which is then going to be used in some +way to kill bacteria okay so we're gonna + + align:start position:0% +way to kill bacteria okay so we're gonna + + + align:start position:0% +way to kill bacteria okay so we're gonna +be talking about neutrophils we're going + + align:start position:0% +be talking about neutrophils we're going + + + align:start position:0% +be talking about neutrophils we're going +to be talking about the knox protein + + align:start position:0% +to be talking about the knox protein + + + align:start position:0% +to be talking about the knox protein +also if you've read the recitation paper + + align:start position:0% +also if you've read the recitation paper + + + align:start position:0% +also if you've read the recitation paper +for today what are we talking about in + + align:start position:0% +for today what are we talking about in + + + align:start position:0% +for today what are we talking about in +signaling that's oxygen-dependent the + + align:start position:0% +signaling that's oxygen-dependent the + + + align:start position:0% +signaling that's oxygen-dependent the +knox proteins so here we have bad we're + + align:start position:0% +knox proteins so here we have bad we're + + + align:start position:0% +knox proteins so here we have bad we're +killing the bacteria here we have good + + align:start position:0% +killing the bacteria here we have good + + + align:start position:0% +killing the bacteria here we have good +we're using the knox proteins for + + align:start position:0% +we're using the knox proteins for + + + align:start position:0% +we're using the knox proteins for +signaling so that's sort of the + + align:start position:0% +signaling so that's sort of the + + + align:start position:0% +signaling so that's sort of the +take-home message is homeostasis how do + + align:start position:0% +take-home message is homeostasis how do + + + align:start position:0% +take-home message is homeostasis how do +you control it for bad versus for good + + align:start position:0% +you control it for bad versus for good + + + align:start position:0% +you control it for bad versus for good +we've already seen that in the case of + + align:start position:0% +we've already seen that in the case of + + + align:start position:0% +we've already seen that in the case of +the iron systems so so the other protein + + align:start position:0% +the iron systems so so the other protein + + + align:start position:0% +the iron systems so so the other protein +we're gonna talk about today or probably + + align:start position:0% +we're gonna talk about today or probably + + + align:start position:0% +we're gonna talk about today or probably +won't get that far today how bad am i + + align:start position:0% +won't get that far today how bad am i + + + align:start position:0% +won't get that far today how bad am i +okay so we have another protein called + + align:start position:0% +okay so we have another protein called + + + align:start position:0% +okay so we have another protein called +milo peroxidase and we're gonna see that + + align:start position:0% +milo peroxidase and we're gonna see that + + + align:start position:0% +milo peroxidase and we're gonna see that +this so this guy is going to be involved + + align:start position:0% +this so this guy is going to be involved + + + align:start position:0% +this so this guy is going to be involved +with superoxide this guy is involved in + + align:start position:0% +with superoxide this guy is involved in + + + align:start position:0% +with superoxide this guy is involved in +the neutrophils Jenner with generating + + align:start position:0% +the neutrophils Jenner with generating + + + align:start position:0% +the neutrophils Jenner with generating +hypochlorous acid so these are the + + align:start position:0% +hypochlorous acid so these are the + + + align:start position:0% +hypochlorous acid so these are the +proteins and these proteins together + + align:start position:0% +proteins and these proteins together + + + align:start position:0% +proteins and these proteins together +I'll give you the model the current + + align:start position:0% +I'll give you the model the current + + + align:start position:0% +I'll give you the model the current +model but the current model I'm going to + + align:start position:0% +model but the current model I'm going to + + + align:start position:0% +model but the current model I'm going to +give you as much simpler than reality + + align:start position:0% +give you as much simpler than reality + + + align:start position:0% +give you as much simpler than reality +okay but those are the proteins we're + + align:start position:0% +okay but those are the proteins we're + + + align:start position:0% +okay but those are the proteins we're +going to + + align:start position:0% +going to + + + align:start position:0% +going to +focus on and those are two of the + + align:start position:0% +focus on and those are two of the + + + align:start position:0% +focus on and those are two of the +reactive species were going to be + + align:start position:0% +reactive species were going to be + + + align:start position:0% +reactive species were going to be +focusing on and then the second lecture + + align:start position:0% +focusing on and then the second lecture + + + align:start position:0% +focusing on and then the second lecture +goes back to the NOx to proteins and the + + align:start position:0% +goes back to the NOx to proteins and the + + + align:start position:0% +goes back to the NOx to proteins and the +question now of not killing but + + align:start position:0% +question now of not killing but + + + align:start position:0% +question now of not killing but +signaling and as we already saw in the + + align:start position:0% +signaling and as we already saw in the + + + align:start position:0% +signaling and as we already saw in the +last in the last recitation how are we + + align:start position:0% +last in the last recitation how are we + + + align:start position:0% +last in the last recitation how are we +sickening we were signaling by from a + + align:start position:0% +sickening we were signaling by from a + + + align:start position:0% +sickening we were signaling by from a +reaction of self fighter groups with + + align:start position:0% +reaction of self fighter groups with + + + align:start position:0% +reaction of self fighter groups with +hydrogen peroxide which can be generated + + align:start position:0% +hydrogen peroxide which can be generated + + + align:start position:0% +hydrogen peroxide which can be generated +from superoxide I'll show you how that + + align:start position:0% +from superoxide I'll show you how that + + + align:start position:0% +from superoxide I'll show you how that +happens + + align:start position:0% +happens + + + align:start position:0% +happens +so signaling and we're focusing on + + align:start position:0% +so signaling and we're focusing on + + + align:start position:0% +so signaling and we're focusing on +signaling by self-immolation which again + + align:start position:0% +signaling by self-immolation which again + + + align:start position:0% +signaling by self-immolation which again +is the topic of today's recitation of + + align:start position:0% +is the topic of today's recitation of + + + align:start position:0% +is the topic of today's recitation of +the epidermal growth factor receptor + + align:start position:0% +the epidermal growth factor receptor + + + align:start position:0% +the epidermal growth factor receptor +okay so that's what we're going okay and + + align:start position:0% +okay so that's what we're going okay and + + + align:start position:0% +okay so that's what we're going okay and +I'm going to give you that we're gonna + + align:start position:0% +I'm going to give you that we're gonna + + + align:start position:0% +I'm going to give you that we're gonna +follow this outline and I think you'll + + align:start position:0% +follow this outline and I think you'll + + + align:start position:0% +follow this outline and I think you'll +get a pretty good feeling for an + + align:start position:0% +get a pretty good feeling for an + + + align:start position:0% +get a pretty good feeling for an +overview of reactive oxygen species even + + align:start position:0% +overview of reactive oxygen species even + + + align:start position:0% +overview of reactive oxygen species even +though we're not going through it in a + + align:start position:0% +though we're not going through it in a + + + align:start position:0% +though we're not going through it in a +lot of details it's really complicated + + align:start position:0% +lot of details it's really complicated + + + align:start position:0% +lot of details it's really complicated +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so what I want to do before I get to + + align:start position:0% +so what I want to do before I get to + + + align:start position:0% +so what I want to do before I get to +this slide is give you the big picture + + align:start position:0% +this slide is give you the big picture + + + align:start position:0% +this slide is give you the big picture +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +okay so this is the take-home message so + + align:start position:0% +okay so this is the take-home message so + + + align:start position:0% +okay so this is the take-home message so +we have a big picture okay and so here + + align:start position:0% +we have a big picture okay and so here + + + align:start position:0% +we have a big picture okay and so here +we have cell okay and in this cell we + + align:start position:0% +we have cell okay and in this cell we + + + align:start position:0% +we have cell okay and in this cell we +have reactive oxygen species and there + + align:start position:0% +have reactive oxygen species and there + + + align:start position:0% +have reactive oxygen species and there +were also things called reactive + + align:start position:0% +were also things called reactive + + + align:start position:0% +were also things called reactive +nitrogen species and you'll see that in + + align:start position:0% +nitrogen species and you'll see that in + + + align:start position:0% +nitrogen species and you'll see that in +some of the slides in the PowerPoint + + align:start position:0% +some of the slides in the PowerPoint + + + align:start position:0% +some of the slides in the PowerPoint +presentation we're not going to talk + + align:start position:0% +presentation we're not going to talk + + + align:start position:0% +presentation we're not going to talk +about that chemistry it's interesting if + + align:start position:0% +about that chemistry it's interesting if + + + align:start position:0% +about that chemistry it's interesting if +I had an extra three or four lectures I + + align:start position:0% +I had an extra three or four lectures I + + + align:start position:0% +I had an extra three or four lectures I +would also be talking about that it's + + align:start position:0% +would also be talking about that it's + + + align:start position:0% +would also be talking about that it's +central it's as important as reactive + + align:start position:0% +central it's as important as reactive + + + align:start position:0% +central it's as important as reactive +oxygen species but I've decided to focus + + align:start position:0% +oxygen species but I've decided to focus + + + align:start position:0% +oxygen species but I've decided to focus +on that's what I've decided to focus on + + align:start position:0% +on that's what I've decided to focus on + + + align:start position:0% +on that's what I've decided to focus on +so we have hydroxide radical we have + + align:start position:0% +so we have hydroxide radical we have + + + align:start position:0% +so we have hydroxide radical we have +hydrogen peroxide + + align:start position:0% +hydrogen peroxide + + + align:start position:0% +hydrogen peroxide +we have superoxide and we have + + align:start position:0% +we have superoxide and we have + + + align:start position:0% +we have superoxide and we have +hypochlorous acid okay so these are the + + align:start position:0% +hypochlorous acid okay so these are the + + + align:start position:0% +hypochlorous acid okay so these are the +four species that we're gonna be focused + + align:start position:0% +four species that we're gonna be focused + + + align:start position:0% +four species that we're gonna be focused +on and you can already see that some of + + align:start position:0% +on and you can already see that some of + + + align:start position:0% +on and you can already see that some of +them are radical and some of them are + + align:start position:0% +them are radical and some of them are + + + align:start position:0% +them are radical and some of them are +not okay so reactive oxygen species + + align:start position:0% +not okay so reactive oxygen species + + + align:start position:0% +not okay so reactive oxygen species +doesn't mean they have a free radical + + align:start position:0% +doesn't mean they have a free radical + + + align:start position:0% +doesn't mean they have a free radical +they can do one electron or two electron + + align:start position:0% +they can do one electron or two electron + + + align:start position:0% +they can do one electron or two electron +chemistry and we'll talk briefly about + + align:start position:0% +chemistry and we'll talk briefly about + + + align:start position:0% +chemistry and we'll talk briefly about +that and so the question is where did + + align:start position:0% +that and so the question is where did + + + align:start position:0% +that and so the question is where did +these come from okay so remember we made + + align:start position:0% +these come from okay so remember we made + + + align:start position:0% +these come from okay so remember we made +a transition from an anaerobic to an + + align:start position:0% +a transition from an anaerobic to an + + + align:start position:0% +a transition from an anaerobic to an +aerobic world a billion years ago and + + align:start position:0% +aerobic world a billion years ago and + + + align:start position:0% +aerobic world a billion years ago and +during that process we have a + + align:start position:0% +during that process we have a + + + align:start position:0% +during that process we have a +respiratory chain in humans the + + align:start position:0% +respiratory chain in humans the + + + align:start position:0% +respiratory chain in humans the +respiratory chain is found in the + + align:start position:0% +respiratory chain is found in the + + + align:start position:0% +respiratory chain is found in the +mitochondria otherwise it's found in the + + align:start position:0% +mitochondria otherwise it's found in the + + + align:start position:0% +mitochondria otherwise it's found in the +plasma membrane so we have complexes 1 2 + + align:start position:0% +plasma membrane so we have complexes 1 2 + + + align:start position:0% +plasma membrane so we have complexes 1 2 +& 3 and these guys do chemistry their + + align:start position:0% +& 3 and these guys do chemistry their + + + align:start position:0% +& 3 and these guys do chemistry their +ultimate goal if you're in an oxygen + + align:start position:0% +ultimate goal if you're in an oxygen + + + align:start position:0% +ultimate goal if you're in an oxygen +oxygen dependent world is to reduce + + align:start position:0% +oxygen dependent world is to reduce + + + align:start position:0% +oxygen dependent world is to reduce +oxygen to water okay so this is a goal + + align:start position:0% +oxygen to water okay so this is a goal + + + align:start position:0% +oxygen to water okay so this is a goal +is oxygen to water although you all know + + align:start position:0% +is oxygen to water although you all know + + + align:start position:0% +is oxygen to water although you all know +in bacteria if there's no oxygen you + + align:start position:0% +in bacteria if there's no oxygen you + + + align:start position:0% +in bacteria if there's no oxygen you +have to have some other terminal + + align:start position:0% +have to have some other terminal + + + align:start position:0% +have to have some other terminal +electron acceptor and so what you get + + align:start position:0% +electron acceptor and so what you get + + + align:start position:0% +electron acceptor and so what you get +from these complexes is uncoupling okay + + align:start position:0% +from these complexes is uncoupling okay + + + align:start position:0% +from these complexes is uncoupling okay +so 100 percent of the time it doesn't do + + align:start position:0% +so 100 percent of the time it doesn't do + + + align:start position:0% +so 100 percent of the time it doesn't do +what you want it to do and so you have + + align:start position:0% +what you want it to do and so you have + + + align:start position:0% +what you want it to do and so you have +to you you get a side reactions that you + + align:start position:0% +to you you get a side reactions that you + + + align:start position:0% +to you you get a side reactions that you +have to deal with you know what I do + + align:start position:0% +have to deal with you know what I do + + + align:start position:0% +have to deal with you know what I do +with my chalk anyhow so you get + + align:start position:0% +with my chalk anyhow so you get + + + align:start position:0% +with my chalk anyhow so you get +uncoupling okay so that's one way if + + align:start position:0% +uncoupling okay so that's one way if + + + align:start position:0% +uncoupling okay so that's one way if +they're generated a second way that + + align:start position:0% +they're generated a second way that + + + align:start position:0% +they're generated a second way that +generated we've already been through we + + align:start position:0% +generated we've already been through we + + + align:start position:0% +generated we've already been through we +went from an anaerobic world to an + + align:start position:0% +went from an anaerobic world to an + + + align:start position:0% +went from an anaerobic world to an +aerobic world what do we have under + + align:start position:0% +aerobic world what do we have under + + + align:start position:0% +aerobic world what do we have under +those conditions we have iron and we + + align:start position:0% +those conditions we have iron and we + + + align:start position:0% +those conditions we have iron and we +have copper and again we have oxygen and + + align:start position:0% +have copper and again we have oxygen and + + + align:start position:0% +have copper and again we have oxygen and +so we can generate reactive oxygen + + align:start position:0% +so we can generate reactive oxygen + + + align:start position:0% +so we can generate reactive oxygen +species we've already talked about the + + align:start position:0% +species we've already talked about the + + + align:start position:0% +species we've already talked about the +fact that iron just isn't freely + + align:start position:0% +fact that iron just isn't freely + + + align:start position:0% +fact that iron just isn't freely +floating around inside the cell but if + + align:start position:0% +floating around inside the cell but if + + + align:start position:0% +floating around inside the cell but if +something happens + + align:start position:0% +something happens + + + align:start position:0% +something happens +and you have been balance in iron + + align:start position:0% +and you have been balance in iron + + + align:start position:0% +and you have been balance in iron +homeostasis it leads to imbalance in + + align:start position:0% +homeostasis it leads to imbalance in + + + align:start position:0% +homeostasis it leads to imbalance in +oxygen homeostasis and hopefully you + + align:start position:0% +oxygen homeostasis and hopefully you + + + align:start position:0% +oxygen homeostasis and hopefully you +remember that one of the proteins + + align:start position:0% +remember that one of the proteins + + + align:start position:0% +remember that one of the proteins +regulated by the iron responsive element + + align:start position:0% +regulated by the iron responsive element + + + align:start position:0% +regulated by the iron responsive element +iron responsive binding proteins was up + + align:start position:0% +iron responsive binding proteins was up + + + align:start position:0% +iron responsive binding proteins was up +the oxygen transcription oxygen sensing + + align:start position:0% +the oxygen transcription oxygen sensing + + + align:start position:0% +the oxygen transcription oxygen sensing +trans transcription factor another way + + align:start position:0% +trans transcription factor another way + + + align:start position:0% +trans transcription factor another way +that we get these things are from + + align:start position:0% +that we get these things are from + + + align:start position:0% +that we get these things are from +xenobiotics or environmental pollutants + + align:start position:0% + + + + align:start position:0% + +if you smoke which I guess people don't + + align:start position:0% +if you smoke which I guess people don't + + + align:start position:0% +if you smoke which I guess people don't +do but when I was in graduate school + + align:start position:0% +do but when I was in graduate school + + + align:start position:0% +do but when I was in graduate school +everybody smoked and they smoked in the + + align:start position:0% +everybody smoked and they smoked in the + + + align:start position:0% +everybody smoked and they smoked in the +lab anyhow you can say so pollutants can + + align:start position:0% +lab anyhow you can say so pollutants can + + + align:start position:0% +lab anyhow you can say so pollutants can +react generate reactive oxygen species + + align:start position:0% +react generate reactive oxygen species + + + align:start position:0% +react generate reactive oxygen species +okay so so that's how we get them what + + align:start position:0% +okay so so that's how we get them what + + + align:start position:0% +okay so so that's how we get them what +do we do with them okay so there's some + + align:start position:0% +do we do with them okay so there's some + + + align:start position:0% +do we do with them okay so there's some +important things that we can do with + + align:start position:0% +important things that we can do with + + + align:start position:0% +important things that we can do with +them so what are we gonna do with them + + align:start position:0% +them so what are we gonna do with them + + + align:start position:0% +them so what are we gonna do with them +so one of the things we can do is we + + align:start position:0% +so one of the things we can do is we + + + align:start position:0% +so one of the things we can do is we +have white blood cells and neutrophils + + align:start position:0% + + + + align:start position:0% + +and we kill bacteria or viruses or + + align:start position:0% +and we kill bacteria or viruses or + + + align:start position:0% +and we kill bacteria or viruses or +parasites okay so that's one of the good + + align:start position:0% +parasites okay so that's one of the good + + + align:start position:0% +parasites okay so that's one of the good +things we can do with them a second + + align:start position:0% +things we can do with them a second + + + align:start position:0% +things we can do with them a second +thing we're gonna do with them which is + + align:start position:0% +thing we're gonna do with them which is + + + align:start position:0% +thing we're gonna do with them which is +what we're focusing on is signaling and + + align:start position:0% +what we're focusing on is signaling and + + + align:start position:0% +what we're focusing on is signaling and +we'll see that while we are looking at + + align:start position:0% +we'll see that while we are looking at + + + align:start position:0% +we'll see that while we are looking at +signaling of growth factors or home + + align:start position:0% +signaling of growth factors or home + + + align:start position:0% +signaling of growth factors or home +hormones or cytokines which is good + + align:start position:0% +hormones or cytokines which is good + + + align:start position:0% +hormones or cytokines which is good +signaling we'll see that you can have + + align:start position:0% +signaling we'll see that you can have + + + align:start position:0% +signaling we'll see that you can have +all kinds of signaling okay so it's not + + align:start position:0% +all kinds of signaling okay so it's not + + + align:start position:0% +all kinds of signaling okay so it's not +limited to the one system we're going to + + align:start position:0% +limited to the one system we're going to + + + align:start position:0% +limited to the one system we're going to +be studying so it's very broadly defined + + align:start position:0% +be studying so it's very broadly defined + + + align:start position:0% +be studying so it's very broadly defined +this is a huge area of research right + + align:start position:0% +this is a huge area of research right + + + align:start position:0% +this is a huge area of research right +now people looking at this and the third + + align:start position:0% +now people looking at this and the third + + + align:start position:0% +now people looking at this and the third +thing that happens when this is + + align:start position:0% +thing that happens when this is + + + align:start position:0% +thing that happens when this is +completely out of control is you modify + + align:start position:0% +completely out of control is you modify + + + align:start position:0% +completely out of control is you modify +you damage all the macromolecules and so + + align:start position:0% +you damage all the macromolecules and so + + + align:start position:0% +you damage all the macromolecules and so +molecules inside the cell so you have + + align:start position:0% +molecules inside the cell so you have + + + align:start position:0% +molecules inside the cell so you have +extensive damage you can have extensive + + align:start position:0% +extensive damage you can have extensive + + + align:start position:0% +extensive damage you can have extensive +damage of you know DNA it's not writing + + align:start position:0% +damage of you know DNA it's not writing + + + align:start position:0% +damage of you know DNA it's not writing +very well proteins but it's not a little + + align:start position:0% +very well proteins but it's not a little + + + align:start position:0% +very well proteins but it's not a little +bit to that you have lipids lipids are + + align:start position:0% +bit to that you have lipids lipids are + + + align:start position:0% +bit to that you have lipids lipids are +modified by hydrogen peroxide and so + + align:start position:0% +modified by hydrogen peroxide and so + + + align:start position:0% +modified by hydrogen peroxide and so +that's the big picture that's where + + align:start position:0% +that's the big picture that's where + + + align:start position:0% +that's the big picture that's where +we're going we're focusing on these guys + + align:start position:0% +we're going we're focusing on these guys + + + align:start position:0% +we're going we're focusing on these guys +and we're focusing on good things that + + align:start position:0% +and we're focusing on good things that + + + align:start position:0% +and we're focusing on good things that +we're focusing on bad things and how do + + align:start position:0% +we're focusing on bad things and how do + + + align:start position:0% +we're focusing on bad things and how do +we control all of that okay okay so in + + align:start position:0% +we control all of that okay okay so in + + + align:start position:0% +we control all of that okay okay so in +the next what I want to do is show you + + align:start position:0% +the next what I want to do is show you + + + align:start position:0% +the next what I want to do is show you +why this is why I decided to talk about + + align:start position:0% +why this is why I decided to talk about + + + align:start position:0% +why this is why I decided to talk about +this I've always found this area + + align:start position:0% +this I've always found this area + + + align:start position:0% +this I've always found this area +fascinating um and I must say I've been + + align:start position:0% +fascinating um and I must say I've been + + + align:start position:0% +fascinating um and I must say I've been +going to meetings off and on for decades + + align:start position:0% +going to meetings off and on for decades + + + align:start position:0% +going to meetings off and on for decades +and I said up quit going because I lost + + align:start position:0% +and I said up quit going because I lost + + + align:start position:0% +and I said up quit going because I lost +information every time I went to a + + align:start position:0% +information every time I went to a + + + align:start position:0% +information every time I went to a +meeting because it was so confusing + + align:start position:0% +meeting because it was so confusing + + + align:start position:0% +meeting because it was so confusing +because everybody used different cell + + align:start position:0% +because everybody used different cell + + + align:start position:0% +because everybody used different cell +types and they have different kinds of + + align:start position:0% +types and they have different kinds of + + + align:start position:0% +types and they have different kinds of +assays and they didn't pay attention to + + align:start position:0% +assays and they didn't pay attention to + + + align:start position:0% +assays and they didn't pay attention to +what the assays were really telling them + + align:start position:0% +what the assays were really telling them + + + align:start position:0% +what the assays were really telling them +but now I think we're at the time when + + align:start position:0% +but now I think we're at the time when + + + align:start position:0% +but now I think we're at the time when +people really need the people are doing + + align:start position:0% +people really need the people are doing + + + align:start position:0% +people really need the people are doing +good experiments I think we've turned a + + align:start position:0% +good experiments I think we've turned a + + + align:start position:0% +good experiments I think we've turned a +corner and so one of the things that is + + align:start position:0% +corner and so one of the things that is + + + align:start position:0% +corner and so one of the things that is +been in the front pages of all the + + align:start position:0% +been in the front pages of all the + + + align:start position:0% +been in the front pages of all the +newspapers since 2007 it was we actually + + align:start position:0% +newspapers since 2007 it was we actually + + + align:start position:0% +newspapers since 2007 it was we actually +there was Jim Collins who was at Boston + + align:start position:0% +there was Jim Collins who was at Boston + + + align:start position:0% +there was Jim Collins who was at Boston +University had received a huge amount of + + align:start position:0% +University had received a huge amount of + + + align:start position:0% +University had received a huge amount of +press on a paper he published in 2007 + + align:start position:0% +press on a paper he published in 2007 + + + align:start position:0% +press on a paper he published in 2007 +and since that time has been extremely + + align:start position:0% +and since that time has been extremely + + + align:start position:0% +and since that time has been extremely +controversial and so I think you it + + align:start position:0% +controversial and so I think you it + + + align:start position:0% +controversial and so I think you it +brings up a lot of issues about again + + align:start position:0% +brings up a lot of issues about again + + + align:start position:0% +brings up a lot of issues about again +how you do controlled experiments so his + + align:start position:0% +how you do controlled experiments so his + + + align:start position:0% +how you do controlled experiments so his +observation his conclusions were from + + align:start position:0% +observation his conclusions were from + + + align:start position:0% +observation his conclusions were from +the experiments he published were very + + align:start position:0% +the experiments he published were very + + + align:start position:0% +the experiments he published were very +interesting so we just talked about + + align:start position:0% +interesting so we just talked about + + + align:start position:0% +interesting so we just talked about +antibiotics right what did they target + + align:start position:0% +antibiotics right what did they target + + + align:start position:0% +antibiotics right what did they target +they target cell walls we have + + align:start position:0% +they target cell walls we have + + + align:start position:0% +they target cell walls we have +penicillin vancomycin they can target + + align:start position:0% +penicillin vancomycin they can target + + + align:start position:0% +penicillin vancomycin they can target +the ribosome you saw that in the first + + align:start position:0% +the ribosome you saw that in the first + + + align:start position:0% +the ribosome you saw that in the first +part of the course you have amino + + align:start position:0% +part of the course you have amino + + + align:start position:0% +part of the course you have amino +glycosides they can target DNA + + align:start position:0% +glycosides they can target DNA + + + align:start position:0% +glycosides they can target DNA +replication so those are the three sort + + align:start position:0% +replication so those are the three sort + + + align:start position:0% +replication so those are the three sort +of major targets you have the clonal ins + + align:start position:0% +of major targets you have the clonal ins + + + align:start position:0% +of major targets you have the clonal ins +that do that + + align:start position:0% +that do that + + + align:start position:0% +that do that +his conclusion from the paper is that + + align:start position:0% +his conclusion from the paper is that + + + align:start position:0% +his conclusion from the paper is that +all of these things the mechanism of + + align:start position:0% +all of these things the mechanism of + + + align:start position:0% +all of these things the mechanism of +cell killed + + align:start position:0% +cell killed + + + align:start position:0% +cell killed +it's not involved with the primary + + align:start position:0% +it's not involved with the primary + + + align:start position:0% +it's not involved with the primary +targets at all but it's involved with a + + align:start position:0% +targets at all but it's involved with a + + + align:start position:0% +targets at all but it's involved with a +downstream target that somehow these + + align:start position:0% +downstream target that somehow these + + + align:start position:0% +downstream target that somehow these +guys undo oxygen homeostasis resulting + + align:start position:0% +guys undo oxygen homeostasis resulting + + + align:start position:0% +guys undo oxygen homeostasis resulting +in bad radicals reactive oxygen species + + align:start position:0% +in bad radicals reactive oxygen species + + + align:start position:0% +in bad radicals reactive oxygen species +that end up damaging macromolecules + + align:start position:0% +that end up damaging macromolecules + + + align:start position:0% +that end up damaging macromolecules +damaging the cell and resulting in + + align:start position:0% +damaging the cell and resulting in + + + align:start position:0% +damaging the cell and resulting in +bacterial cell death okay so that's the + + align:start position:0% +bacterial cell death okay so that's the + + + align:start position:0% +bacterial cell death okay so that's the +model this has been quite controversial + + align:start position:0% +model this has been quite controversial + + + align:start position:0% +model this has been quite controversial +I've given you some papers to read the + + align:start position:0% +I've given you some papers to read the + + + align:start position:0% +I've given you some papers to read the +latest paper was just published online + + align:start position:0% +latest paper was just published online + + + align:start position:0% +latest paper was just published online +saying reactive oxygen species play an + + align:start position:0% +saying reactive oxygen species play an + + + align:start position:0% +saying reactive oxygen species play an +important role in bacterial seidel + + align:start position:0% +important role in bacterial seidel + + + align:start position:0% +important role in bacterial seidel +activity of the Quinlan's that targets + + align:start position:0% +activity of the Quinlan's that targets + + + align:start position:0% +activity of the Quinlan's that targets +topoisomerase in DNA replication but + + align:start position:0% +topoisomerase in DNA replication but + + + align:start position:0% +topoisomerase in DNA replication but +we've had two articles published in + + align:start position:0% +we've had two articles published in + + + align:start position:0% +we've had two articles published in +science saying killing by bacterial + + align:start position:0% +science saying killing by bacterial + + + align:start position:0% +science saying killing by bacterial +antibiotics does not depend on reactive + + align:start position:0% +antibiotics does not depend on reactive + + + align:start position:0% +antibiotics does not depend on reactive +oxygen species so we've had quite + + align:start position:0% +oxygen species so we've had quite + + + align:start position:0% +oxygen species so we've had quite +inflammatory responses to this paper + + align:start position:0% +inflammatory responses to this paper + + + align:start position:0% +inflammatory responses to this paper +which I at one stage didn't believe + + align:start position:0% +which I at one stage didn't believe + + + align:start position:0% +which I at one stage didn't believe +anything that he did because I think if + + align:start position:0% +anything that he did because I think if + + + align:start position:0% +anything that he did because I think if +you look at the original a lot of the + + align:start position:0% +you look at the original a lot of the + + + align:start position:0% +you look at the original a lot of the +original experiments they use reagents + + align:start position:0% +original experiments they use reagents + + + align:start position:0% +original experiments they use reagents +that were completely non specific for + + align:start position:0% +that were completely non specific for + + + align:start position:0% +that were completely non specific for +what they thought they were okay but I + + align:start position:0% +what they thought they were okay but I + + + align:start position:0% +what they thought they were okay but I +think I am now I think his observations + + align:start position:0% +think I am now I think his observations + + + align:start position:0% +think I am now I think his observations +in fact were correct but not some of his + + align:start position:0% +in fact were correct but not some of his + + + align:start position:0% +in fact were correct but not some of his +observations were correct but the + + align:start position:0% +observations were correct but the + + + align:start position:0% +observations were correct but the +reasoning behind the observations has + + align:start position:0% +reasoning behind the observations has + + + align:start position:0% +reasoning behind the observations has +changed and I think there is something + + align:start position:0% +changed and I think there is something + + + align:start position:0% +changed and I think there is something +about this you do signaling up here and + + align:start position:0% +about this you do signaling up here and + + + align:start position:0% +about this you do signaling up here and +then where do you see something way down + + align:start position:0% +then where do you see something way down + + + align:start position:0% +then where do you see something way down +here because you trigger off a signaling + + align:start position:0% +here because you trigger off a signaling + + + align:start position:0% +here because you trigger off a signaling +cascade and that's the way the world + + align:start position:0% +cascade and that's the way the world + + + align:start position:0% +cascade and that's the way the world +works inside the cell so a second + + align:start position:0% +works inside the cell so a second + + + align:start position:0% +works inside the cell so a second +example of this which also received a + + align:start position:0% +example of this which also received a + + + align:start position:0% +example of this which also received a +lot of press this guy everybody know who + + align:start position:0% +lot of press this guy everybody know who + + + align:start position:0% +lot of press this guy everybody know who +this guy is you know the DNA guy the + + align:start position:0% +this guy is you know the DNA guy the + + + align:start position:0% +this guy is you know the DNA guy the +famous these Emil chauvinist pig but the + + align:start position:0% +famous these Emil chauvinist pig but the + + + align:start position:0% +famous these Emil chauvinist pig but the +DNA guys anyhow what he you know there's + + align:start position:0% +DNA guys anyhow what he you know there's + + + align:start position:0% +DNA guys anyhow what he you know there's +been a big fight our reactive oxygen + + align:start position:0% +been a big fight our reactive oxygen + + + align:start position:0% +been a big fight our reactive oxygen +species good or bad and fighting cancer + + align:start position:0% +species good or bad and fighting cancer + + + align:start position:0% +species good or bad and fighting cancer +so some people say again it's the + + align:start position:0% +so some people say again it's the + + + align:start position:0% +so some people say again it's the +reactive oxygen species that eventually + + align:start position:0% +reactive oxygen species that eventually + + + align:start position:0% +reactive oxygen species that eventually +kill the cancer cells again you do + + align:start position:0% +kill the cancer cells again you do + + + align:start position:0% +kill the cancer cells again you do +something up here you trigger off a set + + align:start position:0% +something up here you trigger off a set + + + align:start position:0% +something up here you trigger off a set +of events you generate a pathway that + + align:start position:0% +of events you generate a pathway that + + + align:start position:0% +of events you generate a pathway that +generates react about + + align:start position:0% +generates react about + + + align:start position:0% +generates react about +oxygen species that helps kill the tumor + + align:start position:0% +oxygen species that helps kill the tumor + + + align:start position:0% +oxygen species that helps kill the tumor +cells or do they stimulate growth + + align:start position:0% +cells or do they stimulate growth + + + align:start position:0% +cells or do they stimulate growth +reactive oxygen species stimulate growth + + align:start position:0% +reactive oxygen species stimulate growth + + + align:start position:0% +reactive oxygen species stimulate growth +or do they trigger apoptosis okay so + + align:start position:0% +or do they trigger apoptosis okay so + + + align:start position:0% +or do they trigger apoptosis okay so +people are still debating that and + + align:start position:0% +people are still debating that and + + + align:start position:0% +people are still debating that and +there's probably some truth in both of + + align:start position:0% +there's probably some truth in both of + + + align:start position:0% +there's probably some truth in both of +these statements depending on how you + + align:start position:0% +these statements depending on how you + + + align:start position:0% +these statements depending on how you +look at it anyhow that's just to get you + + align:start position:0% +look at it anyhow that's just to get you + + + align:start position:0% +look at it anyhow that's just to get you +thinking about the fact that this is an + + align:start position:0% +thinking about the fact that this is an + + + align:start position:0% +thinking about the fact that this is an +important area um that a lot of people + + align:start position:0% +important area um that a lot of people + + + align:start position:0% +important area um that a lot of people +are actually focusing energy on okay so + + align:start position:0% +are actually focusing energy on okay so + + + align:start position:0% +are actually focusing energy on okay so +what I want to do now is we've you've + + align:start position:0% +what I want to do now is we've you've + + + align:start position:0% +what I want to do now is we've you've +given a big overview what I want to do + + align:start position:0% +given a big overview what I want to do + + + align:start position:0% +given a big overview what I want to do +now is look at what are the species + + align:start position:0% +now is look at what are the species + + + align:start position:0% +now is look at what are the species +identification of the species and the + + align:start position:0% +identification of the species and the + + + align:start position:0% +identification of the species and the +species we're gonna be focusing on again + + align:start position:0% +species we're gonna be focusing on again + + + align:start position:0% +species we're gonna be focusing on again +or superoxide I write this down later + + align:start position:0% +or superoxide I write this down later + + + align:start position:0% +or superoxide I write this down later +hydrogen peroxide h2o2 hypochlorous acid + + align:start position:0% +hydrogen peroxide h2o2 hypochlorous acid + + + align:start position:0% +hydrogen peroxide h2o2 hypochlorous acid +and hydroxide radical okay so this is + + align:start position:0% +and hydroxide radical okay so this is + + + align:start position:0% +and hydroxide radical okay so this is +this is a scheme that was taken from a + + align:start position:0% +this is a scheme that was taken from a + + + align:start position:0% +this is a scheme that was taken from a +Winterbourne articles so it's in all of + + align:start position:0% +Winterbourne articles so it's in all of + + + align:start position:0% +Winterbourne articles so it's in all of +her papers I don't know if it's I don't + + align:start position:0% +her papers I don't know if it's I don't + + + align:start position:0% +her papers I don't know if it's I don't +know if it's the exact same scheme and + + align:start position:0% +know if it's the exact same scheme and + + + align:start position:0% +know if it's the exact same scheme and +the reading assignment but you'll see + + align:start position:0% +the reading assignment but you'll see + + + align:start position:0% +the reading assignment but you'll see +something similar and we're not a told + + align:start position:0% +something similar and we're not a told + + + align:start position:0% +something similar and we're not a told +you we're not going to talk about + + align:start position:0% +you we're not going to talk about + + + align:start position:0% +you we're not going to talk about +reactive oxygen species we're only + + align:start position:0% +reactive oxygen species we're only + + + align:start position:0% +reactive oxygen species we're only +focusing on reactive sorry reactive + + align:start position:0% +focusing on reactive sorry reactive + + + align:start position:0% +focusing on reactive sorry reactive +nitrogen species we're only focusing on + + align:start position:0% +nitrogen species we're only focusing on + + + align:start position:0% +nitrogen species we're only focusing on +reactive oxygen species but this gives + + align:start position:0% +reactive oxygen species but this gives + + + align:start position:0% +reactive oxygen species but this gives +you the big picture with both okay so + + align:start position:0% +you the big picture with both okay so + + + align:start position:0% +you the big picture with both okay so +where are we going to be focusing oxygen + + align:start position:0% +where are we going to be focusing oxygen + + + align:start position:0% +where are we going to be focusing oxygen +I picks up an electron and goes to + + align:start position:0% +I picks up an electron and goes to + + + align:start position:0% +I picks up an electron and goes to +superoxide superoxide and the presence + + align:start position:0% +superoxide superoxide and the presence + + + align:start position:0% +superoxide superoxide and the presence +of another electron and protons goes to + + align:start position:0% +of another electron and protons goes to + + + align:start position:0% +of another electron and protons goes to +hydrogen peroxide so we're going to be + + align:start position:0% +hydrogen peroxide so we're going to be + + + align:start position:0% +hydrogen peroxide so we're going to be +focusing here hydrogen peroxide in the + + align:start position:0% +focusing here hydrogen peroxide in the + + + align:start position:0% +focusing here hydrogen peroxide in the +presence of iron - okay if we want we've + + align:start position:0% +presence of iron - okay if we want we've + + + align:start position:0% +presence of iron - okay if we want we've +somehow screwed up our iron and we're in + + align:start position:0% +somehow screwed up our iron and we're in + + + align:start position:0% +somehow screwed up our iron and we're in +the reduced state generates hydroxide + + align:start position:0% +the reduced state generates hydroxide + + + align:start position:0% +the reduced state generates hydroxide +radical okay hydrogen peroxide with my + + align:start position:0% +radical okay hydrogen peroxide with my + + + align:start position:0% +radical okay hydrogen peroxide with my +low peroxidase in in the neutrophils + + align:start position:0% +low peroxidase in in the neutrophils + + + align:start position:0% +low peroxidase in in the neutrophils +forms hypochlorous acid and so at which + + align:start position:0% +forms hypochlorous acid and so at which + + + align:start position:0% +forms hypochlorous acid and so at which +eventually can chlorinate everything + + align:start position:0% +eventually can chlorinate everything + + + align:start position:0% +eventually can chlorinate everything +they chlorinate amino acids a chlorinate + + align:start position:0% +they chlorinate amino acids a chlorinate + + + align:start position:0% +they chlorinate amino acids a chlorinate +slippage + + align:start position:0% +slippage + + + align:start position:0% +slippage +and can result in extensive damage to + + align:start position:0% +and can result in extensive damage to + + + align:start position:0% +and can result in extensive damage to +whatever hypochlorous accident acid is + + align:start position:0% +whatever hypochlorous accident acid is + + + align:start position:0% +whatever hypochlorous accident acid is +adjacent to so this is what this is + + align:start position:0% +adjacent to so this is what this is + + + align:start position:0% +adjacent to so this is what this is +where we're gonna be focusing okay this + + align:start position:0% +where we're gonna be focusing okay this + + + align:start position:0% +where we're gonna be focusing okay this +part of the scheme those of you who has + + align:start position:0% +part of the scheme those of you who has + + + align:start position:0% +part of the scheme those of you who has +seen reactive nitrogen species can look + + align:start position:0% +seen reactive nitrogen species can look + + + align:start position:0% +seen reactive nitrogen species can look +at how that gets integrated into this + + align:start position:0% +at how that gets integrated into this + + + align:start position:0% +at how that gets integrated into this +big picture okay so I just want to write + + align:start position:0% +big picture okay so I just want to write + + + align:start position:0% +big picture okay so I just want to write +down one of these things I think it's + + align:start position:0% +down one of these things I think it's + + + align:start position:0% +down one of these things I think it's +important to think about ultimately + + align:start position:0% +important to think about ultimately + + + align:start position:0% +important to think about ultimately +we're doing chemistry this whoops I mean + + align:start position:0% +we're doing chemistry this whoops I mean + + + align:start position:0% +we're doing chemistry this whoops I mean +this is like it's terrible it's all of a + + align:start position:0% +this is like it's terrible it's all of a + + + align:start position:0% +this is like it's terrible it's all of a +sudden I look up I it's a good thing I + + align:start position:0% +sudden I look up I it's a good thing I + + + align:start position:0% +sudden I look up I it's a good thing I +looked up because I would have kept + + align:start position:0% +looked up because I would have kept + + + align:start position:0% +looked up because I would have kept +going anyhow sorry the time is over but + + align:start position:0% +going anyhow sorry the time is over but + + + align:start position:0% +going anyhow sorry the time is over but +next time we will come back and we will + + align:start position:0% +next time we will come back and we will + + + align:start position:0% +next time we will come back and we will +talk about what I outlined on the board + + align:start position:0% +talk about what I outlined on the board + + + align:start position:0% +talk about what I outlined on the board +and I didn't even digress today I'm just + + align:start position:0% + + + + align:start position:0% + +you \ No newline at end of file diff --git a/VieMadwoNNs.txt b/VieMadwoNNs.txt new file mode 100644 index 0000000000000000000000000000000000000000..c7797a2c0b4b1dcaaf96910f4fde3c2f8059537e --- /dev/null +++ b/VieMadwoNNs.txt @@ -0,0 +1,1395 @@ +align:start position:0% + +since you are enrolled in this course + + align:start position:0% +since you are enrolled in this course + + + align:start position:0% +since you are enrolled in this course +let's assume that you have decided on or + + align:start position:0% +let's assume that you have decided on or + + + align:start position:0% +let's assume that you have decided on or +perhaps are already engaged in a + + align:start position:0% +perhaps are already engaged in a + + + align:start position:0% +perhaps are already engaged in a +managerial or professional + + align:start position:0% +managerial or professional + + + align:start position:0% +managerial or professional +career and that you are developing or + + align:start position:0% +career and that you are developing or + + + align:start position:0% +career and that you are developing or +have already developed the Knowledge and + + align:start position:0% +have already developed the Knowledge and + + + align:start position:0% +have already developed the Knowledge and +Skills necessary to do the job that's + + align:start position:0% +Skills necessary to do the job that's + + + align:start position:0% +Skills necessary to do the job that's +great but don't stop there experts agree + + align:start position:0% +great but don't stop there experts agree + + + align:start position:0% +great but don't stop there experts agree +that it will take a special set of + + align:start position:0% +that it will take a special set of + + + align:start position:0% +that it will take a special set of +competencies to succeed in tomorrow's + + align:start position:0% +competencies to succeed in tomorrow's + + + align:start position:0% +competencies to succeed in tomorrow's +organizations which will be even more + + align:start position:0% +organizations which will be even more + + + align:start position:0% +organizations which will be even more +globalized digitized collaborative and + + align:start position:0% +globalized digitized collaborative and + + + align:start position:0% +globalized digitized collaborative and +agile than those we see + + align:start position:0% +agile than those we see + + + align:start position:0% +agile than those we see +today many have written on this topic + + align:start position:0% +today many have written on this topic + + + align:start position:0% +today many have written on this topic +one of the best sources we think is a + + align:start position:0% +one of the best sources we think is a + + + align:start position:0% +one of the best sources we think is a +small monograph published by The + + align:start position:0% +small monograph published by The + + + align:start position:0% +small monograph published by The +Institute of the future titled future of + + align:start position:0% +Institute of the future titled future of + + + align:start position:0% +Institute of the future titled future of +work skills 2020 + + align:start position:0% +work skills 2020 + + + align:start position:0% +work skills 2020 +here is a brief synopsis of the 10 + + align:start position:0% +here is a brief synopsis of the 10 + + + align:start position:0% +here is a brief synopsis of the 10 +competencies that the Institute suggests + + align:start position:0% +competencies that the Institute suggests + + + align:start position:0% +competencies that the Institute suggests +will be essential for your career + + align:start position:0% +will be essential for your career + + + align:start position:0% +will be essential for your career +success in the years + + align:start position:0% +success in the years + + + align:start position:0% +success in the years +ahead first relating to + + align:start position:0% +ahead first relating to + + + align:start position:0% +ahead first relating to +globalization The Institute stresses the + + align:start position:0% +globalization The Institute stresses the + + + align:start position:0% +globalization The Institute stresses the +need for cross-cultural competency which + + align:start position:0% +need for cross-cultural competency which + + + align:start position:0% +need for cross-cultural competency which +has a couple of key components one is + + align:start position:0% +has a couple of key components one is + + + align:start position:0% +has a couple of key components one is +the ability to work effectively with + + align:start position:0% +the ability to work effectively with + + + align:start position:0% +the ability to work effectively with +those from other cultures perhaps in + + align:start position:0% +those from other cultures perhaps in + + + align:start position:0% +those from other cultures perhaps in +teams made up of many different + + align:start position:0% +teams made up of many different + + + align:start position:0% +teams made up of many different +nationalities and the other is the + + align:start position:0% +nationalities and the other is the + + + align:start position:0% +nationalities and the other is the +ability to work effectively outside of + + align:start position:0% +ability to work effectively outside of + + + align:start position:0% +ability to work effectively outside of +your native land and while most business + + align:start position:0% +your native land and while most business + + + align:start position:0% +your native land and while most business +probably will continue to be conducted + + align:start position:0% +probably will continue to be conducted + + + align:start position:0% +probably will continue to be conducted +in English it certainly wouldn't hurt to + + align:start position:0% +in English it certainly wouldn't hurt to + + + align:start position:0% +in English it certainly wouldn't hurt to +have a familiarity with other languages + + align:start position:0% +have a familiarity with other languages + + + align:start position:0% +have a familiarity with other languages +as + + align:start position:0% +as + + + align:start position:0% +as +well turning to the circle label + + align:start position:0% +well turning to the circle label + + + align:start position:0% +well turning to the circle label +digitization we see that there are four + + align:start position:0% +digitization we see that there are four + + + align:start position:0% +digitization we see that there are four +key competencies involved one is sense + + align:start position:0% +key competencies involved one is sense + + + align:start position:0% +key competencies involved one is sense +making + + align:start position:0% +making + + + align:start position:0% +making +the future will be all about Mass data + + align:start position:0% +the future will be all about Mass data + + + align:start position:0% +the future will be all about Mass data +we will be even more inundated than we + + align:start position:0% +we will be even more inundated than we + + + align:start position:0% +we will be even more inundated than we +are now so it will be necessary to have + + align:start position:0% +are now so it will be necessary to have + + + align:start position:0% +are now so it will be necessary to have +the capacity to work through tons of + + align:start position:0% +the capacity to work through tons of + + + align:start position:0% +the capacity to work through tons of +information and see the big picture + + align:start position:0% +information and see the big picture + + + align:start position:0% +information and see the big picture +we'll have to be critical thinkers but + + align:start position:0% +we'll have to be critical thinkers but + + + align:start position:0% +we'll have to be critical thinkers but +we also have to keep in mind that + + align:start position:0% +we also have to keep in mind that + + + align:start position:0% +we also have to keep in mind that +technology isn't good for everything so + + align:start position:0% +technology isn't good for everything so + + + align:start position:0% +technology isn't good for everything so +we need to develop the capacity to + + align:start position:0% +we need to develop the capacity to + + + align:start position:0% +we need to develop the capacity to +decide when to rely on computers for + + align:start position:0% +decide when to rely on computers for + + + align:start position:0% +decide when to rely on computers for +assistance and answers and just as + + align:start position:0% +assistance and answers and just as + + + align:start position:0% +assistance and answers and just as +important when not + + align:start position:0% +important when not + + + align:start position:0% +important when not +to a second competency in this area is + + align:start position:0% +to a second competency in this area is + + + align:start position:0% +to a second competency in this area is +computational thinking this includes + + align:start position:0% +computational thinking this includes + + + align:start position:0% +computational thinking this includes +developing a basic understanding of + + align:start position:0% +developing a basic understanding of + + + align:start position:0% +developing a basic understanding of +computer programming and simulation + + align:start position:0% +computer programming and simulation + + + align:start position:0% +computer programming and simulation +modeling it doesn't mean that we all + + align:start position:0% +modeling it doesn't mean that we all + + + align:start position:0% +modeling it doesn't mean that we all +have to become computer geeks in the era + + align:start position:0% +have to become computer geeks in the era + + + align:start position:0% +have to become computer geeks in the era +of big data we can rely on specially + + align:start position:0% +of big data we can rely on specially + + + align:start position:0% +of big data we can rely on specially +trained data scientists to do the heavy + + align:start position:0% +trained data scientists to do the heavy + + + align:start position:0% +trained data scientists to do the heavy +lifting but the rest of us will need to + + align:start position:0% +lifting but the rest of us will need to + + + align:start position:0% +lifting but the rest of us will need to +know enough about what the experts are + + align:start position:0% +know enough about what the experts are + + + align:start position:0% +know enough about what the experts are +doing to be actively involved in the + + align:start position:0% +doing to be actively involved in the + + + align:start position:0% +doing to be actively involved in the +process in two ways one is on the front + + align:start position:0% +process in two ways one is on the front + + + align:start position:0% +process in two ways one is on the front +end to frame questions and problems in + + align:start position:0% +end to frame questions and problems in + + + align:start position:0% +end to frame questions and problems in +ways that the data scientist can analyze + + align:start position:0% +ways that the data scientist can analyze + + + align:start position:0% +ways that the data scientist can analyze +or model and two on the back end to be + + align:start position:0% +or model and two on the back end to be + + + align:start position:0% +or model and two on the back end to be +the ones who interpret the results and + + align:start position:0% +the ones who interpret the results and + + + align:start position:0% +the ones who interpret the results and +come up with value added answers and + + align:start position:0% +come up with value added answers and + + + align:start position:0% +come up with value added answers and +solutions third in this context there is + + align:start position:0% +solutions third in this context there is + + + align:start position:0% +solutions third in this context there is +the issue of new media literacy here the + + align:start position:0% +the issue of new media literacy here the + + + align:start position:0% +the issue of new media literacy here the +reference is to becoming expert in the + + align:start position:0% +reference is to becoming expert in the + + + align:start position:0% +reference is to becoming expert in the +use of social media tools internets + + align:start position:0% +use of social media tools internets + + + align:start position:0% +use of social media tools internets +blogs podcasts videos and so forth in + + align:start position:0% +blogs podcasts videos and so forth in + + + align:start position:0% +blogs podcasts videos and so forth in +the future many folks will be working + + align:start position:0% +the future many folks will be working + + + align:start position:0% +the future many folks will be working +remotely and will be called upon to + + align:start position:0% +remotely and will be called upon to + + + align:start position:0% +remotely and will be called upon to +create and share content through these + + align:start position:0% +create and share content through these + + + align:start position:0% +create and share content through these +Technologies and to do so in ways that + + align:start position:0% +Technologies and to do so in ways that + + + align:start position:0% +Technologies and to do so in ways that +not only help solve complex problems but + + align:start position:0% +not only help solve complex problems but + + + align:start position:0% +not only help solve complex problems but +also engage and persuade our colleagues + + align:start position:0% +also engage and persuade our colleagues + + + align:start position:0% +also engage and persuade our colleagues +and other important people such as + + align:start position:0% +and other important people such as + + + align:start position:0% +and other important people such as +customers and + + align:start position:0% +customers and + + + align:start position:0% +customers and +clients finally in this area is + + align:start position:0% +clients finally in this area is + + + align:start position:0% +clients finally in this area is +cognitive load Management in tomorrow's + + align:start position:0% +cognitive load Management in tomorrow's + + + align:start position:0% +cognitive load Management in tomorrow's +World it will be very easy to get + + align:start position:0% +World it will be very easy to get + + + align:start position:0% +World it will be very easy to get +overwhelmed by the mass of information + + align:start position:0% +overwhelmed by the mass of information + + + align:start position:0% +overwhelmed by the mass of information +that's bound to come our way we need to + + align:start position:0% +that's bound to come our way we need to + + + align:start position:0% +that's bound to come our way we need to +learn how to avoid this how to evaluate + + align:start position:0% +learn how to avoid this how to evaluate + + + align:start position:0% +learn how to avoid this how to evaluate +Rank and tag content so that we keep our + + align:start position:0% +Rank and tag content so that we keep our + + + align:start position:0% +Rank and tag content so that we keep our +eyes on what's really important and let + + align:start position:0% +eyes on what's really important and let + + + align:start position:0% +eyes on what's really important and let +the rest + + align:start position:0% +the rest + + + align:start position:0% +the rest +go some somewhat ironically computer + + align:start position:0% +go some somewhat ironically computer + + + align:start position:0% +go some somewhat ironically computer +programs are already available to help + + align:start position:0% +programs are already available to help + + + align:start position:0% +programs are already available to help +with this they have the ability to sense + + align:start position:0% +with this they have the ability to sense + + + align:start position:0% +with this they have the ability to sense +when we are becoming overloaded or tired + + align:start position:0% +when we are becoming overloaded or tired + + + align:start position:0% +when we are becoming overloaded or tired +and then to automatically intervene to + + align:start position:0% +and then to automatically intervene to + + + align:start position:0% +and then to automatically intervene to +slow down or simplify the flow of + + align:start position:0% +slow down or simplify the flow of + + + align:start position:0% +slow down or simplify the flow of +information we're + + align:start position:0% +information we're + + + align:start position:0% +information we're +getting third let's turn to the issue of + + align:start position:0% +getting third let's turn to the issue of + + + align:start position:0% +getting third let's turn to the issue of +collaboration one essential competency + + align:start position:0% +collaboration one essential competency + + + align:start position:0% +collaboration one essential competency +here is social + + align:start position:0% +here is social + + + align:start position:0% +here is social +intelligence this refers to the ability + + align:start position:0% +intelligence this refers to the ability + + + align:start position:0% +intelligence this refers to the ability +to connect with with others in an + + align:start position:0% +to connect with with others in an + + + align:start position:0% +to connect with with others in an +emotional and deeply personal way to + + align:start position:0% +emotional and deeply personal way to + + + align:start position:0% +emotional and deeply personal way to +quickly assess the feelings of others + + align:start position:0% +quickly assess the feelings of others + + + align:start position:0% +quickly assess the feelings of others +and then adapt our words tone and + + align:start position:0% +and then adapt our words tone and + + + align:start position:0% +and then adapt our words tone and +gestures accordingly everyone agrees + + align:start position:0% +gestures accordingly everyone agrees + + + align:start position:0% +gestures accordingly everyone agrees +that this is a uniquely human competency + + align:start position:0% +that this is a uniquely human competency + + + align:start position:0% +that this is a uniquely human competency +that so far at least gives us a leg up + + align:start position:0% +that so far at least gives us a leg up + + + align:start position:0% +that so far at least gives us a leg up +on + + align:start position:0% +on + + + align:start position:0% +on +robots further The Institute talks about + + align:start position:0% +robots further The Institute talks about + + + align:start position:0% +robots further The Institute talks about +virtual collaboration meaning the + + align:start position:0% +virtual collaboration meaning the + + + align:start position:0% +virtual collaboration meaning the +ability to work effectively with and + + align:start position:0% +ability to work effectively with and + + + align:start position:0% +ability to work effectively with and +eventually perhap perhaps lead teammates + + align:start position:0% +eventually perhap perhaps lead teammates + + + align:start position:0% +eventually perhap perhaps lead teammates +we may never meet or even see in person + + align:start position:0% +we may never meet or even see in person + + + align:start position:0% +we may never meet or even see in person +this involves becoming really good at + + align:start position:0% +this involves becoming really good at + + + align:start position:0% +this involves becoming really good at +turning in-house networks and New Media + + align:start position:0% +turning in-house networks and New Media + + + align:start position:0% +turning in-house networks and New Media +into what some call social water coolers + + align:start position:0% +into what some call social water coolers + + + align:start position:0% +into what some call social water coolers +important tools helping to enhance a + + align:start position:0% +important tools helping to enhance a + + + align:start position:0% +important tools helping to enhance a +sense of + + align:start position:0% +sense of + + + align:start position:0% +sense of +camaraderie and social presence among + + align:start position:0% +camaraderie and social presence among + + + align:start position:0% +camaraderie and social presence among +colleagues who are all over the + + align:start position:0% +colleagues who are all over the + + + align:start position:0% +colleagues who are all over the +map online Gamers already have a leg up + + align:start position:0% +map online Gamers already have a leg up + + + align:start position:0% +map online Gamers already have a leg up +on developing this competency + + align:start position:0% +on developing this competency + + + align:start position:0% +on developing this competency +since this is in large part what they + + align:start position:0% +since this is in large part what they + + + align:start position:0% +since this is in large part what they +are learning to + + align:start position:0% +are learning to + + + align:start position:0% +are learning to +do and finally let's consider agility + + align:start position:0% +do and finally let's consider agility + + + align:start position:0% +do and finally let's consider agility +which really is the capacity to be + + align:start position:0% +which really is the capacity to be + + + align:start position:0% +which really is the capacity to be +comfortable with change three + + align:start position:0% +comfortable with change three + + + align:start position:0% +comfortable with change three +competencies are stressed here one is + + align:start position:0% +competencies are stressed here one is + + + align:start position:0% +competencies are stressed here one is +novel and adaptive thinking in a world + + align:start position:0% +novel and adaptive thinking in a world + + + align:start position:0% +novel and adaptive thinking in a world +of Rapid change it is essential that we + + align:start position:0% +of Rapid change it is essential that we + + + align:start position:0% +of Rapid change it is essential that we +never let the tried and true get in the + + align:start position:0% +never let the tried and true get in the + + + align:start position:0% +never let the tried and true get in the +way of being open to new ways of doing + + align:start position:0% +way of being open to new ways of doing + + + align:start position:0% +way of being open to new ways of doing +things in the future all of us will be + + align:start position:0% +things in the future all of us will be + + + align:start position:0% +things in the future all of us will be +expected to keep our eyes on + + align:start position:0% +expected to keep our eyes on + + + align:start position:0% +expected to keep our eyes on +developments that are going on in the + + align:start position:0% +developments that are going on in the + + + align:start position:0% +developments that are going on in the +world so that we can anticipate upcoming + + align:start position:0% +world so that we can anticipate upcoming + + + align:start position:0% +world so that we can anticipate upcoming +challenges and most important be on the + + align:start position:0% +challenges and most important be on the + + + align:start position:0% +challenges and most important be on the +Leading Edge of developing unique and + + align:start position:0% +Leading Edge of developing unique and + + + align:start position:0% +Leading Edge of developing unique and +creative ideas and solutions to deal + + align:start position:0% +creative ideas and solutions to deal + + + align:start position:0% +creative ideas and solutions to deal +with these challenges in real + + align:start position:0% +with these challenges in real + + + align:start position:0% +with these challenges in real +time second The Institute talks about + + align:start position:0% +time second The Institute talks about + + + align:start position:0% +time second The Institute talks about +design mindset this is closely related + + align:start position:0% +design mindset this is closely related + + + align:start position:0% +design mindset this is closely related +to novel and adaptive thinking + + align:start position:0% +to novel and adaptive thinking + + + align:start position:0% +to novel and adaptive thinking +it refers to being super familiar with + + align:start position:0% +it refers to being super familiar with + + + align:start position:0% +it refers to being super familiar with +our work situation so that we can see + + align:start position:0% +our work situation so that we can see + + + align:start position:0% +our work situation so that we can see +when changes need to be made but even + + align:start position:0% +when changes need to be made but even + + + align:start position:0% +when changes need to be made but even +more important it refers to having the + + align:start position:0% +more important it refers to having the + + + align:start position:0% +more important it refers to having the +ability to make useful recommendations + + align:start position:0% +ability to make useful recommendations + + + align:start position:0% +ability to make useful recommendations +for redesigning the work environment as + + align:start position:0% +for redesigning the work environment as + + + align:start position:0% +for redesigning the work environment as +well as the processes and procedures + + align:start position:0% +well as the processes and procedures + + + align:start position:0% +well as the processes and procedures +being used to get the work + + align:start position:0% +being used to get the work + + + align:start position:0% +being used to get the work +done and then there is what the + + align:start position:0% +done and then there is what the + + + align:start position:0% +done and then there is what the +Institute calls transdisciplinarity + + align:start position:0% +Institute calls transdisciplinarity + + + align:start position:0% +Institute calls transdisciplinarity +which is a big word for a simple idea in + + align:start position:0% +which is a big word for a simple idea in + + + align:start position:0% +which is a big word for a simple idea in +the future the ideal worker will be + + align:start position:0% +the future the ideal worker will be + + + align:start position:0% +the future the ideal worker will be +t-shaped that is deeply expert in one or + + align:start position:0% +t-shaped that is deeply expert in one or + + + align:start position:0% +t-shaped that is deeply expert in one or +more disciplines which is the vertical + + align:start position:0% +more disciplines which is the vertical + + + align:start position:0% +more disciplines which is the vertical +part of the te but also knowledgeable + + align:start position:0% +part of the te but also knowledgeable + + + align:start position:0% +part of the te but also knowledgeable +about and comfortable with many other + + align:start position:0% +about and comfortable with many other + + + align:start position:0% +about and comfortable with many other +disciplines the horizontal part of the + + align:start position:0% +disciplines the horizontal part of the + + + align:start position:0% +disciplines the horizontal part of the +tea in other words once you're world + + align:start position:0% +tea in other words once you're world + + + align:start position:0% +tea in other words once you're world +class at one thing make sure you keep + + align:start position:0% +class at one thing make sure you keep + + + align:start position:0% +class at one thing make sure you keep +right on learning about a lot of other + + align:start position:0% +right on learning about a lot of other + + + align:start position:0% +right on learning about a lot of other +things success in the future will depend + + align:start position:0% +things success in the future will depend + + + align:start position:0% +things success in the future will depend +on our willingness and ability to keep + + align:start position:0% +on our willingness and ability to keep + + + align:start position:0% +on our willingness and ability to keep +growing and + + align:start position:0% +growing and + + + align:start position:0% +growing and +developing to become more Global in our + + align:start position:0% +developing to become more Global in our + + + align:start position:0% +developing to become more Global in our +thinking more comfortable with the + + align:start position:0% +thinking more comfortable with the + + + align:start position:0% +thinking more comfortable with the +digitization of everything ever better + + align:start position:0% +digitization of everything ever better + + + align:start position:0% +digitization of everything ever better +at collaborating with colleagues and + + align:start position:0% +at collaborating with colleagues and + + + align:start position:0% +at collaborating with colleagues and +others and above all staying deeply + + align:start position:0% +others and above all staying deeply + + + align:start position:0% +others and above all staying deeply +committed to being adaptive lifelong + + align:start position:0% +committed to being adaptive lifelong + + + align:start position:0% +committed to being adaptive lifelong +learners \ No newline at end of file diff --git a/WMDXIL3IvBg.txt b/WMDXIL3IvBg.txt new file mode 100644 index 0000000000000000000000000000000000000000..ccc95461407455582cbb7026ca58c4b71f6d2432 --- /dev/null +++ b/WMDXIL3IvBg.txt @@ -0,0 +1,12115 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +view additional materials from hundreds + + align:start position:0% +view additional materials from hundreds + + + align:start position:0% +view additional materials from hundreds +of MIT courses visit MIT opencourseware + + align:start position:0% +of MIT courses visit MIT opencourseware + + + align:start position:0% +of MIT courses visit MIT opencourseware +at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu I hope you're getting + + align:start position:0% +ocw.mit.edu I hope you're getting + + + align:start position:0% +ocw.mit.edu I hope you're getting +excited about the + + align:start position:0% +excited about the + + + align:start position:0% +excited about the +trip um so there are a few things that I + + align:start position:0% +trip um so there are a few things that I + + + align:start position:0% +trip um so there are a few things that I +managed to skip over last time one is + + align:start position:0% +managed to skip over last time one is + + + align:start position:0% +managed to skip over last time one is +solar cookers somehow got dropped from + + align:start position:0% +solar cookers somehow got dropped from + + + align:start position:0% +solar cookers somehow got dropped from +my presentation and they're kind of key + + align:start position:0% +my presentation and they're kind of key + + + align:start position:0% +my presentation and they're kind of key +part of cooking that I wanted to talk + + align:start position:0% +part of cooking that I wanted to talk + + + align:start position:0% +part of cooking that I wanted to talk +about um at least most of you guys have + + align:start position:0% +about um at least most of you guys have + + + align:start position:0% +about um at least most of you guys have +investigated a little bit on your own + + align:start position:0% +investigated a little bit on your own + + + align:start position:0% +investigated a little bit on your own +and then we also just talking about the + + align:start position:0% +and then we also just talking about the + + + align:start position:0% +and then we also just talking about the +energy to boil water so in terms of + + align:start position:0% +energy to boil water so in terms of + + + align:start position:0% +energy to boil water so in terms of +solar cookers there as uh groupo Phoenix + + align:start position:0% +solar cookers there as uh groupo Phoenix + + + align:start position:0% +solar cookers there as uh groupo Phoenix +mentioned there are three types so + + align:start position:0% +mentioned there are three types so + + + align:start position:0% +mentioned there are three types so +there's + + align:start position:0% +there's + + + align:start position:0% +there's +the concentrator par parabolic method + + align:start position:0% +the concentrator par parabolic method + + + align:start position:0% +the concentrator par parabolic method +where you have some sort of parabolic + + align:start position:0% +where you have some sort of parabolic + + + align:start position:0% +where you have some sort of parabolic +collector that's aiming the heat onto + + align:start position:0% +collector that's aiming the heat onto + + + align:start position:0% +collector that's aiming the heat onto +your cooking cook stove which is then + + align:start position:0% +your cooking cook stove which is then + + + align:start position:0% +your cooking cook stove which is then +heating up the material you have the box + + align:start position:0% +heating up the material you have the box + + + align:start position:0% +heating up the material you have the box +method which is using a greenhouse + + align:start position:0% +method which is using a greenhouse + + + align:start position:0% +method which is using a greenhouse +method um where you have a reflective + + align:start position:0% +method um where you have a reflective + + + align:start position:0% +method um where you have a reflective +device uh reflecting into the greenhouse + + align:start position:0% +device uh reflecting into the greenhouse + + + align:start position:0% +device uh reflecting into the greenhouse +and that's pretty much the design that + + align:start position:0% +and that's pretty much the design that + + + align:start position:0% +and that's pretty much the design that +um group of Phoenix uses I wouldn't call + + align:start position:0% +um group of Phoenix uses I wouldn't call + + + align:start position:0% +um group of Phoenix uses I wouldn't call +it a hybrid because the hybrid has both + + align:start position:0% +it a hybrid because the hybrid has both + + + align:start position:0% +it a hybrid because the hybrid has both +that Greenhouse but also uses some + + align:start position:0% +that Greenhouse but also uses some + + + align:start position:0% +that Greenhouse but also uses some +parabolic features to collect the energy + + align:start position:0% +parabolic features to collect the energy + + + align:start position:0% +parabolic features to collect the energy +um and you can see that the cost you can + + align:start position:0% +um and you can see that the cost you can + + + align:start position:0% +um and you can see that the cost you can +imagine the cost of these three devices + + align:start position:0% +imagine the cost of these three devices + + + align:start position:0% +imagine the cost of these three devices +shown varies and so you can get very + + align:start position:0% +shown varies and so you can get very + + + align:start position:0% +shown varies and so you can get very +inexpensive versions of all of these but + + align:start position:0% +inexpensive versions of all of these but + + + align:start position:0% +inexpensive versions of all of these but +the parabolic is definitely the hardest + + align:start position:0% +the parabolic is definitely the hardest + + + align:start position:0% +the parabolic is definitely the hardest +to get super cheap um and very expensive + + align:start position:0% +to get super cheap um and very expensive + + + align:start position:0% +to get super cheap um and very expensive +versions so I wanted to start by just um + + align:start position:0% +versions so I wanted to start by just um + + + align:start position:0% +versions so I wanted to start by just um +talking about what you think might be + + align:start position:0% +talking about what you think might be + + + align:start position:0% +talking about what you think might be +some pros and cons of solar cookers + + align:start position:0% + + + + align:start position:0% + +I a question yeah is the refle material + + align:start position:0% +I a question yeah is the refle material + + + align:start position:0% +I a question yeah is the refle material +that they use what is + + align:start position:0% + + + + align:start position:0% + +it just she metal + + align:start position:0% +it just she metal + + + align:start position:0% +it just she metal +or like aluminum foil so sheet metal is + + align:start position:0% +or like aluminum foil so sheet metal is + + + align:start position:0% +or like aluminum foil so sheet metal is +pretty + + align:start position:0% + + + + align:start position:0% + +uh yeah yeah it's hard to get a really + + align:start position:0% +uh yeah yeah it's hard to get a really + + + align:start position:0% +uh yeah yeah it's hard to get a really +good reflection off of it so I think + + align:start position:0% +good reflection off of it so I think + + + align:start position:0% +good reflection off of it so I think +I've seen some that are like basically + + align:start position:0% +I've seen some that are like basically + + + align:start position:0% +I've seen some that are like basically +mirrors so um is I think what that is um + + align:start position:0% +mirrors so um is I think what that is um + + + align:start position:0% +mirrors so um is I think what that is um +this + + align:start position:0% +this + + + align:start position:0% +this +is um like a plastic that's super shiny + + align:start position:0% +is um like a plastic that's super shiny + + + align:start position:0% +is um like a plastic that's super shiny +that's just laminated onto the cardboard + + align:start position:0% +that's just laminated onto the cardboard + + + align:start position:0% +that's just laminated onto the cardboard +so a whole range from expensive to + + align:start position:0% +so a whole range from expensive to + + + align:start position:0% +so a whole range from expensive to +non I have a question um so the one that + + align:start position:0% +non I have a question um so the one that + + + align:start position:0% +non I have a question um so the one that +uh is the concentrator where does what + + align:start position:0% +uh is the concentrator where does what + + + align:start position:0% +uh is the concentrator where does what +is it concentrating towards the box or + + align:start position:0% +is it concentrating towards the box or + + + align:start position:0% +is it concentrating towards the box or +towards no so this is an open pan so + + align:start position:0% +towards no so this is an open pan so + + + align:start position:0% +towards no so this is an open pan so +this just concentrating it on the + + align:start position:0% +this just concentrating it on the + + + align:start position:0% +this just concentrating it on the +pan so that these this is the difference + + align:start position:0% +pan so that these this is the difference + + + align:start position:0% +pan so that these this is the difference +the concentrator is is just you know + + align:start position:0% +the concentrator is is just you know + + + align:start position:0% +the concentrator is is just you know +shining a strong Ray of heat onto + + align:start position:0% +shining a strong Ray of heat onto + + + align:start position:0% +shining a strong Ray of heat onto +something mostly just not Electric solar + + align:start position:0% +something mostly just not Electric solar + + + align:start position:0% +something mostly just not Electric solar +cookers are very rarely electrical I've + + align:start position:0% +cookers are very rarely electrical I've + + + align:start position:0% +cookers are very rarely electrical I've +never seen one of we talking about was + + align:start position:0% +never seen one of we talking about was + + + align:start position:0% +never seen one of we talking about was +like having a bigger panel maybe each + + align:start position:0% +like having a bigger panel maybe each + + + align:start position:0% +like having a bigger panel maybe each +house Community where you can charge the + + align:start position:0% +house Community where you can charge the + + + align:start position:0% +house Community where you can charge the +cell phone and you can also um cook but + + align:start position:0% +cell phone and you can also um cook but + + + align:start position:0% +cell phone and you can also um cook but +then that would have that like we were + + align:start position:0% +then that would have that like we were + + + align:start position:0% +then that would have that like we were +thinking about like the panel outside on + + align:start position:0% +thinking about like the panel outside on + + + align:start position:0% +thinking about like the panel outside on +the roof + + align:start position:0% +the roof + + + align:start position:0% +the roof +collecting collecting the Rays + + align:start position:0% +collecting collecting the Rays + + + align:start position:0% +collecting collecting the Rays +collecting the like solar energy + + align:start position:0% +collecting the like solar energy + + + align:start position:0% +collecting the like solar energy +transferring it into like + + align:start position:0% +transferring it into like + + + align:start position:0% +transferring it into like +electrical energy and uh getting it to + + align:start position:0% +electrical energy and uh getting it to + + + align:start position:0% +electrical energy and uh getting it to +to the solar cooker and the so I think + + align:start position:0% +to the solar cooker and the so I think + + + align:start position:0% +to the solar cooker and the so I think +that would be a really good estimation + + align:start position:0% +that would be a really good estimation + + + align:start position:0% +that would be a really good estimation +exercise to figure out what it takes to + + align:start position:0% +exercise to figure out what it takes to + + + align:start position:0% +exercise to figure out what it takes to +make a solar cooker that's an electrical + + align:start position:0% +make a solar cooker that's an electrical + + + align:start position:0% +make a solar cooker that's an electrical +solar cooker um because do you remember + + align:start position:0% +solar cooker um because do you remember + + + align:start position:0% +solar cooker um because do you remember +how many watts a + + align:start position:0% +how many watts a + + + align:start position:0% +how many watts a +typical stove or oven + + align:start position:0% +typical stove or oven + + + align:start position:0% +typical stove or oven +is yeah + + align:start position:0% +is yeah + + + align:start position:0% +is yeah +and so like a typical like burner is + + align:start position:0% +and so like a typical like burner is + + + align:start position:0% +and so like a typical like burner is +1,000 to 1500 watts a typical oven is + + align:start position:0% +1,000 to 1500 watts a typical oven is + + + align:start position:0% +1,000 to 1500 watts a typical oven is +3,000 Watts so we're talking really + + align:start position:0% +3,000 Watts so we're talking really + + + align:start position:0% +3,000 Watts so we're talking really +different Scopes in terms of what a cell + + align:start position:0% +different Scopes in terms of what a cell + + + align:start position:0% +different Scopes in terms of what a cell +phone charger is and what cooking is + + align:start position:0% +phone charger is and what cooking is + + + align:start position:0% +phone charger is and what cooking is +needs to be and so um that's a high + + align:start position:0% +needs to be and so um that's a high + + + align:start position:0% +needs to be and so um that's a high +barrier to entry so you need to look + + align:start position:0% +barrier to entry so you need to look + + + align:start position:0% +barrier to entry so you need to look +into the viability of + + align:start position:0% + + + + align:start position:0% + +that okay so can we make a list of what + + align:start position:0% +that okay so can we make a list of what + + + align:start position:0% +that okay so can we make a list of what +you think are the bonuses of Sor cookers + + align:start position:0% +you think are the bonuses of Sor cookers + + + align:start position:0% +you think are the bonuses of Sor cookers +and what are some of the drawbacks Benji + + align:start position:0% +and what are some of the drawbacks Benji + + + align:start position:0% +and what are some of the drawbacks Benji +um it's free after you buy it yeah so + + align:start position:0% +um it's free after you buy it yeah so + + + align:start position:0% +um it's free after you buy it yeah so +it's free + + align:start position:0% + + + + align:start position:0% + +energy zero emissions y + + align:start position:0% + + + + align:start position:0% + +a con is that you might not be able to + + align:start position:0% +a con is that you might not be able to + + + align:start position:0% +a con is that you might not be able to +have it right outside your home like + + align:start position:0% +have it right outside your home like + + + align:start position:0% +have it right outside your home like +that girl standing in a river which is + + align:start position:0% +that girl standing in a river which is + + + align:start position:0% +that girl standing in a river which is +probably not + + align:start position:0% +probably not + + + align:start position:0% +probably not +outside um so + + align:start position:0% +outside um so + + + align:start position:0% +outside um so +uh how do we so it needs to be like it + + align:start position:0% +uh how do we so it needs to be like it + + + align:start position:0% +uh how do we so it needs to be like it +needs to be out to find a sunny location + + align:start position:0% + + + + align:start position:0% + +yeah it's depending on weather and time + + align:start position:0% +yeah it's depending on weather and time + + + align:start position:0% +yeah it's depending on weather and time +of day + + align:start position:0% + + + + align:start position:0% + +said um apart from the conator cookers + + align:start position:0% +said um apart from the conator cookers + + + align:start position:0% +said um apart from the conator cookers +they can't fry food yeah so your your + + align:start position:0% +they can't fry food yeah so your your + + + align:start position:0% +they can't fry food yeah so your your +your cooking options are limited + + align:start position:0% + + + + align:start position:0% + +so yeah you can absolutely fry food with + + align:start position:0% +so yeah you can absolutely fry food with + + + align:start position:0% +so yeah you can absolutely fry food with +the concentrator but it can be hard to + + align:start position:0% +the concentrator but it can be hard to + + + align:start position:0% +the concentrator but it can be hard to +get a low heat if you want a low heat in + + align:start position:0% +get a low heat if you want a low heat in + + + align:start position:0% +get a low heat if you want a low heat in +a + + align:start position:0% +a + + + align:start position:0% +a +concentrator Carter excuse me + + align:start position:0% +concentrator Carter excuse me + + + align:start position:0% +concentrator Carter excuse me +portability + + align:start position:0% +portability + + + align:start position:0% +portability +portability yeah so I'll put that in the + + align:start position:0% + + + + align:start position:0% + +middle well and there's a real guility + + align:start position:0% +middle well and there's a real guility + + + align:start position:0% +middle well and there's a real guility +would + + align:start position:0% +would + + + align:start position:0% +would +be uh but + + align:start position:0% +be uh but + + + align:start position:0% +be uh but +scale that you can move it around but + + align:start position:0% +scale that you can move it around but + + + align:start position:0% +scale that you can move it around but +only to a certain size well but you can + + align:start position:0% +only to a certain size well but you can + + + align:start position:0% +only to a certain size well but you can +see here so like this is a highly + + align:start position:0% +see here so like this is a highly + + + align:start position:0% +see here so like this is a highly +portable solar cooker that that parabell + + align:start position:0% +portable solar cooker that that parabell + + + align:start position:0% +portable solar cooker that that parabell +concentrator actually folds up into + + align:start position:0% +concentrator actually folds up into + + + align:start position:0% +concentrator actually folds up into +something that's not much bigger like + + align:start position:0% +something that's not much bigger like + + + align:start position:0% +something that's not much bigger like +it's significantly smaller than this so + + align:start position:0% +it's significantly smaller than this so + + + align:start position:0% +it's significantly smaller than this so +that is super portable whereas the + + align:start position:0% +that is super portable whereas the + + + align:start position:0% +that is super portable whereas the +concentr that concentrator is a fixed + + align:start position:0% +concentr that concentrator is a fixed + + + align:start position:0% +concentr that concentrator is a fixed +location so some are portable some are + + align:start position:0% +location so some are portable some are + + + align:start position:0% +location so some are portable some are +not um and then if they're portable that + + align:start position:0% +not um and then if they're portable that + + + align:start position:0% +not um and then if they're portable that +can be helpful but then it's limited by + + align:start position:0% +can be helpful but then it's limited by + + + align:start position:0% +can be helpful but then it's limited by +size so I think actually leaving it in + + align:start position:0% +size so I think actually leaving it in + + + align:start position:0% +size so I think actually leaving it in +the middle is + + align:start position:0% + + + + align:start position:0% + +reasonable + + align:start position:0% +reasonable + + + align:start position:0% +reasonable +c yeah + + align:start position:0% +c yeah + + + align:start position:0% +c yeah +um I don't know if that is TR any more + + align:start position:0% +um I don't know if that is TR any more + + + align:start position:0% +um I don't know if that is TR any more +true than it is for any + + align:start position:0% + + + + align:start position:0% + +stove any other thoughts + + align:start position:0% + + + + align:start position:0% + +yeah let me see + + align:start position:0% +yeah let me see + + + align:start position:0% +yeah let me see +obviously haveit + + align:start position:0% +obviously haveit + + + align:start position:0% +obviously haveit +impr yeah so no emissions which + + align:start position:0% +impr yeah so no emissions which + + + align:start position:0% +impr yeah so no emissions which +yields this better + + align:start position:0% + + + + align:start position:0% + +health there's also no preparation time + + align:start position:0% +health there's also no preparation time + + + align:start position:0% +health there's also no preparation time +like you don't need to collect fuel yeah + + align:start position:0% +like you don't need to collect fuel yeah + + + align:start position:0% +like you don't need to collect fuel yeah +so no no fuel + + align:start position:0% +so no no fuel + + + align:start position:0% +so no no fuel +collection which sort of links to that + + align:start position:0% +collection which sort of links to that + + + align:start position:0% +collection which sort of links to that +one so cuz it's either time or money + + align:start position:0% +one so cuz it's either time or money + + + align:start position:0% +one so cuz it's either time or money +generally Sid I guess our would be that + + align:start position:0% +generally Sid I guess our would be that + + + align:start position:0% +generally Sid I guess our would be that +you constantly like change the Angles + + align:start position:0% +you constantly like change the Angles + + + align:start position:0% +you constantly like change the Angles +and you're cooking for for a long period + + align:start position:0% +and you're cooking for for a long period + + + align:start position:0% +and you're cooking for for a long period +of time so + + align:start position:0% + + + + align:start position:0% + +um okay yeah + + align:start position:0% + + + + align:start position:0% + +Beni so if someone you know if someone + + align:start position:0% +Beni so if someone you know if someone + + + align:start position:0% +Beni so if someone you know if someone +wants to have I don't + + align:start position:0% +wants to have I don't + + + align:start position:0% +wants to have I don't +know you're not using + + align:start position:0% +know you're not using + + + align:start position:0% +know you're not using +any yep so because people do use their + + align:start position:0% +any yep so because people do use their + + + align:start position:0% +any yep so because people do use their +Fires for heating for mosquito + + align:start position:0% +Fires for heating for mosquito + + + align:start position:0% +Fires for heating for mosquito +control for light sometimes yeah + + align:start position:0% + + + + align:start position:0% + +okay super so I think that's a pretty + + align:start position:0% +okay super so I think that's a pretty + + + align:start position:0% +okay super so I think that's a pretty +good list to give you some background + + align:start position:0% +good list to give you some background + + + align:start position:0% +good list to give you some background +solar cookers were invented in the mid + + align:start position:0% +solar cookers were invented in the mid + + + align:start position:0% +solar cookers were invented in the mid +1700s so they've been around for a + + align:start position:0% +1700s so they've been around for a + + + align:start position:0% +1700s so they've been around for a +really long time and I think that + + align:start position:0% +really long time and I think that + + + align:start position:0% +really long time and I think that +is an indicator of how this is a great + + align:start position:0% +is an indicator of how this is a great + + + align:start position:0% +is an indicator of how this is a great +technology in some cases but isn't ever + + align:start position:0% +technology in some cases but isn't ever + + + align:start position:0% +technology in some cases but isn't ever +going to be the killer app that solves + + align:start position:0% +going to be the killer app that solves + + + align:start position:0% +going to be the killer app that solves +the world's cooking challenges uh + + align:start position:0% +the world's cooking challenges uh + + + align:start position:0% +the world's cooking challenges uh +because one would think if they been + + align:start position:0% +because one would think if they been + + + align:start position:0% +because one would think if they been +around since the 1700s that the + + align:start position:0% +around since the 1700s that the + + + align:start position:0% +around since the 1700s that the +refinement that takes it to killer app + + align:start position:0% +refinement that takes it to killer app + + + align:start position:0% +refinement that takes it to killer app +would have been developed already but + + align:start position:0% +would have been developed already but + + + align:start position:0% +would have been developed already but +the cons of it weather dependent it's + + align:start position:0% +the cons of it weather dependent it's + + + align:start position:0% +the cons of it weather dependent it's +time dependent you need to be in a sunny + + align:start position:0% +time dependent you need to be in a sunny + + + align:start position:0% +time dependent you need to be in a sunny +location you need to be outside are all + + align:start position:0% +location you need to be outside are all + + + align:start position:0% +location you need to be outside are all +really huge um so some of the challenges + + align:start position:0% +really huge um so some of the challenges + + + align:start position:0% +really huge um so some of the challenges +with the concentrators are the glare and + + align:start position:0% +with the concentrators are the glare and + + + align:start position:0% +with the concentrators are the glare and +just how hot it is so it's kind of hard + + align:start position:0% +just how hot it is so it's kind of hard + + + align:start position:0% +just how hot it is so it's kind of hard +to see cuz the um quality of the picture + + align:start position:0% +to see cuz the um quality of the picture + + + align:start position:0% +to see cuz the um quality of the picture +has gone down going through the + + align:start position:0% +has gone down going through the + + + align:start position:0% +has gone down going through the +projector but this woman is sort of + + align:start position:0% +projector but this woman is sort of + + + align:start position:0% +projector but this woman is sort of +grimac + + align:start position:0% +grimac + + + align:start position:0% +grimac +because it's so bright that it's + + align:start position:0% +because it's so bright that it's + + + align:start position:0% +because it's so bright that it's +actually hard to um to deal with and + + align:start position:0% +actually hard to um to deal with and + + + align:start position:0% +actually hard to um to deal with and +it's also + + align:start position:0% +it's also + + + align:start position:0% +it's also +um very hot where it is yeah is it + + align:start position:0% +um very hot where it is yeah is it + + + align:start position:0% +um very hot where it is yeah is it +dangerous yeah so the the concentrators + + align:start position:0% +dangerous yeah so the the concentrators + + + align:start position:0% +dangerous yeah so the the concentrators +in particular are dangerous and so + + align:start position:0% +in particular are dangerous and so + + + align:start position:0% +in particular are dangerous and so +people are really concerned especially + + align:start position:0% +people are really concerned especially + + + align:start position:0% +people are really concerned especially +with kids um you know it's getting not + + align:start position:0% +with kids um you know it's getting not + + + align:start position:0% +with kids um you know it's getting not +permanently but temporary blinded or + + align:start position:0% +permanently but temporary blinded or + + + align:start position:0% +permanently but temporary blinded or +burned um there's also issues that you + + align:start position:0% +burned um there's also issues that you + + + align:start position:0% +burned um there's also issues that you +can imagine how easy that would + + align:start position:0% +can imagine how easy that would + + + align:start position:0% +can imagine how easy that would +be voila + + align:start position:0% +be voila + + + align:start position:0% +be voila +so I have a really quick question for + + align:start position:0% +so I have a really quick question for + + + align:start position:0% +so I have a really quick question for +all of you anyone wearing shoes with + + align:start position:0% +all of you anyone wearing shoes with + + + align:start position:0% +all of you anyone wearing shoes with +laces can you please stand + + align:start position:0% + + + + align:start position:0% + +up and the rest of you just look around + + align:start position:0% +up and the rest of you just look around + + + align:start position:0% +up and the rest of you just look around +get a good look at + + align:start position:0% +get a good look at + + + align:start position:0% +get a good look at +uh who who has laces and who + + align:start position:0% +uh who who has laces and who + + + align:start position:0% +uh who who has laces and who +doesn't this thing clipped on here + + align:start position:0% + + + + align:start position:0% + +okay thank you guys you can sit + + align:start position:0% +okay thank you guys you can sit + + + align:start position:0% +okay thank you guys you can sit +down + + align:start position:0% +down + + + align:start position:0% +down +um so I I hate to break it to you like + + align:start position:0% +um so I I hate to break it to you like + + + align:start position:0% +um so I I hate to break it to you like +this um but you know I can see a lot of + + align:start position:0% +this um but you know I can see a lot of + + + align:start position:0% +this um but you know I can see a lot of +the way you tied your laces and a lot of + + align:start position:0% +the way you tied your laces and a lot of + + + align:start position:0% +the way you tied your laces and a lot of +you just use like the simple like bunny + + align:start position:0% +you just use like the simple like bunny + + + align:start position:0% +you just use like the simple like bunny +ears kind of knot you learned when you + + align:start position:0% +ears kind of knot you learned when you + + + align:start position:0% +ears kind of knot you learned when you +were like five or six you know which was + + align:start position:0% +were like five or six you know which was + + + align:start position:0% +were like five or six you know which was +great when you learned it and worked + + align:start position:0% +great when you learned it and worked + + + align:start position:0% +great when you learned it and worked +well um but honestly now it's kind of a + + align:start position:0% +well um but honestly now it's kind of a + + + align:start position:0% +well um but honestly now it's kind of a +dumb knot to + + align:start position:0% +dumb knot to + + + align:start position:0% +dumb knot to +use uh I you've been using your whole + + align:start position:0% +use uh I you've been using your whole + + + align:start position:0% +use uh I you've been using your whole +life but um you know I I can stand up + + align:start position:0% +life but um you know I I can stand up + + + align:start position:0% +life but um you know I I can stand up +here and tell you that because uh so I'm + + align:start position:0% +here and tell you that because uh so I'm + + + align:start position:0% +here and tell you that because uh so I'm +I'm a graduate student here mechanical + + align:start position:0% +I'm a graduate student here mechanical + + + align:start position:0% +I'm a graduate student here mechanical +engineering um which if you haven't + + align:start position:0% +engineering um which if you haven't + + + align:start position:0% +engineering um which if you haven't +heard is probably the best mechanical + + align:start position:0% +heard is probably the best mechanical + + + align:start position:0% +heard is probably the best mechanical +engineering department in the + + align:start position:0% +engineering department in the + + + align:start position:0% +engineering department in the +world um so you know I've learned all + + align:start position:0% +world um so you know I've learned all + + + align:start position:0% +world um so you know I've learned all +about design and like good designs and + + align:start position:0% +about design and like good designs and + + + align:start position:0% +about design and like good designs and +bad designs um and these bunny ear knots + + align:start position:0% +bad designs um and these bunny ear knots + + + align:start position:0% +bad designs um and these bunny ear knots +are are pretty bad + + align:start position:0% +are are pretty bad + + + align:start position:0% +are are pretty bad +designs um you know if you want we could + + align:start position:0% +designs um you know if you want we could + + + align:start position:0% +designs um you know if you want we could +sit here and analyze the stresses in + + align:start position:0% +sit here and analyze the stresses in + + + align:start position:0% +sit here and analyze the stresses in +them and and kind of of where are the + + align:start position:0% +them and and kind of of where are the + + + align:start position:0% +them and and kind of of where are the +equilibrium points and why does it stay + + align:start position:0% +equilibrium points and why does it stay + + + align:start position:0% +equilibrium points and why does it stay +tied and why does it always come untied + + align:start position:0% +tied and why does it always come untied + + + align:start position:0% +tied and why does it always come untied +um but you know the summary of all that + + align:start position:0% +um but you know the summary of all that + + + align:start position:0% +um but you know the summary of all that +is just it's a bad not and you guys + + align:start position:0% +is just it's a bad not and you guys + + + align:start position:0% +is just it's a bad not and you guys +should learn a new one uh but thankfully + + align:start position:0% +should learn a new one uh but thankfully + + + align:start position:0% +should learn a new one uh but thankfully +I'm I'm here and I'm going to go through + + align:start position:0% +I'm I'm here and I'm going to go through + + + align:start position:0% +I'm I'm here and I'm going to go through +and teach you how to tie it better or + + align:start position:0% + + + + align:start position:0% + +not okay so I'm going to kind of step + + align:start position:0% +not okay so I'm going to kind of step + + + align:start position:0% +not okay so I'm going to kind of step +out of that character and ask you just + + align:start position:0% +out of that character and ask you just + + + align:start position:0% +out of that character and ask you just +real quickly to share kind of thoughts + + align:start position:0% +real quickly to share kind of thoughts + + + align:start position:0% +real quickly to share kind of thoughts +or feelings of that experience and kind + + align:start position:0% +or feelings of that experience and kind + + + align:start position:0% +or feelings of that experience and kind +of what I said or what I did that made + + align:start position:0% +of what I said or what I did that made + + + align:start position:0% +of what I said or what I did that made +you think or feel the way you are now I + + align:start position:0% +you think or feel the way you are now I + + + align:start position:0% +you think or feel the way you are now I +don't actually + + align:start position:0% +don't actually + + + align:start position:0% +don't actually +use okay that + + align:start position:0% +use okay that + + + align:start position:0% +use okay that +work other anyone else yeah he whispered + + align:start position:0% +work other anyone else yeah he whispered + + + align:start position:0% +work other anyone else yeah he whispered +to me he's like I don't should have my + + align:start position:0% +to me he's like I don't should have my + + + align:start position:0% +to me he's like I don't should have my +shoes + + align:start position:0% + + + + align:start position:0% + +tied you pointed out the people who were + + align:start position:0% +tied you pointed out the people who were + + + align:start position:0% +tied you pointed out the people who were +doing it wrong which might make them + + align:start position:0% +doing it wrong which might make them + + + align:start position:0% +doing it wrong which might make them +feel bad though I don't think people + + align:start position:0% +feel bad though I don't think people + + + align:start position:0% +feel bad though I don't think people +here actually feel too bad about the way + + align:start position:0% +here actually feel too bad about the way + + + align:start position:0% +here actually feel too bad about the way +they tie their shoes + + align:start position:0% + + + + align:start position:0% + +yeah goe how you been say again how have + + align:start position:0% +yeah goe how you been say again how have + + + align:start position:0% +yeah goe how you been say again how have +you been D I've been well + + align:start position:0% +you been D I've been well + + + align:start position:0% +you been D I've been well +um so yeah + + align:start position:0% +um so yeah + + + align:start position:0% +um so yeah +so any other thoughts about how I came + + align:start position:0% +so any other thoughts about how I came + + + align:start position:0% +so any other thoughts about how I came +across I I obviously have this idea that + + align:start position:0% +across I I obviously have this idea that + + + align:start position:0% +across I I obviously have this idea that +I want to get you to learn how to tie + + align:start position:0% +I want to get you to learn how to tie + + + align:start position:0% +I want to get you to learn how to tie +your shoes differently do you think that + + align:start position:0% +your shoes differently do you think that + + + align:start position:0% +your shoes differently do you think that +was the best + + align:start position:0% +was the best + + + align:start position:0% +was the best +approach so it was good cuz you're + + align:start position:0% +approach so it was good cuz you're + + + align:start position:0% +approach so it was good cuz you're +really confident and so it was easy to + + align:start position:0% +really confident and so it was easy to + + + align:start position:0% +really confident and so it was easy to +listen to you and your kind of argument + + align:start position:0% +listen to you and your kind of argument + + + align:start position:0% +listen to you and your kind of argument +and the flow of your conversation was + + align:start position:0% +and the flow of your conversation was + + + align:start position:0% +and the flow of your conversation was +really easy to follow but + + align:start position:0% +really easy to follow but + + + align:start position:0% +really easy to follow but +also think you were overconfident for + + align:start position:0% +also think you were overconfident for + + + align:start position:0% +also think you were overconfident for +such a simple topic and in fact Al you + + align:start position:0% +such a simple topic and in fact Al you + + + align:start position:0% +such a simple topic and in fact Al you +brought uh the whole MIT thing I think + + align:start position:0% +brought uh the whole MIT thing I think + + + align:start position:0% +brought uh the whole MIT thing I think +for us it's good cuz we're all the MIT + + align:start position:0% +for us it's good cuz we're all the MIT + + + align:start position:0% +for us it's good cuz we're all the MIT +of course but I don't know how that + + align:start position:0% +of course but I don't know how that + + + align:start position:0% +of course but I don't know how that +would go with other people like so you + + align:start position:0% +would go with other people like so you + + + align:start position:0% +would go with other people like so you +think you're I don't know it seemed like + + align:start position:0% +think you're I don't know it seemed like + + + align:start position:0% +think you're I don't know it seemed like +you just you thought you were better + + align:start position:0% +you just you thought you were better + + + align:start position:0% +you just you thought you were better +than us cuz like arrogant exactly yeah I + + align:start position:0% +than us cuz like arrogant exactly yeah I + + + align:start position:0% +than us cuz like arrogant exactly yeah I +was trying to be + + align:start position:0% +was trying to be + + + align:start position:0% +was trying to be +um right I mean I also I assumed there's + + align:start position:0% +um right I mean I also I assumed there's + + + align:start position:0% +um right I mean I also I assumed there's +a problem right I assumed that you're + + align:start position:0% +a problem right I assumed that you're + + + align:start position:0% +a problem right I assumed that you're +not happy with the way you're tying your + + align:start position:0% +not happy with the way you're tying your + + + align:start position:0% +not happy with the way you're tying your +shoes right and it said have a better + + align:start position:0% +shoes right and it said have a better + + + align:start position:0% +shoes right and it said have a better +way um like you said I ostracized + + align:start position:0% +way um like you said I ostracized + + + align:start position:0% +way um like you said I ostracized +someone who tied their shoes differently + + align:start position:0% +someone who tied their shoes differently + + + align:start position:0% +someone who tied their shoes differently +um I didn't introduce myself at all I + + align:start position:0% +um I didn't introduce myself at all I + + + align:start position:0% +um I didn't introduce myself at all I +just kind of barged in here and said hey + + align:start position:0% +just kind of barged in here and said hey + + + align:start position:0% +just kind of barged in here and said hey +let me tell you about this right just + + align:start position:0% +let me tell you about this right just + + + align:start position:0% +let me tell you about this right just +the personal connection is a pretty + + align:start position:0% +the personal connection is a pretty + + + align:start position:0% +the personal connection is a pretty +important thing when you're working with + + align:start position:0% +important thing when you're working with + + + align:start position:0% +important thing when you're working with +people + + align:start position:0% +people + + + align:start position:0% +people +um you know also I didn't really ask any + + align:start position:0% +um you know also I didn't really ask any + + + align:start position:0% +um you know also I didn't really ask any +information from you other than could + + align:start position:0% +information from you other than could + + + align:start position:0% +information from you other than could +you stand up if you have shoes that tie + + align:start position:0% +you stand up if you have shoes that tie + + + align:start position:0% +you stand up if you have shoes that tie +with laces right there was no other + + align:start position:0% +with laces right there was no other + + + align:start position:0% +with laces right there was no other +exchange of information right and so if + + align:start position:0% +exchange of information right and so if + + + align:start position:0% +exchange of information right and so if +I'm coming in here and I'm trying to + + align:start position:0% +I'm coming in here and I'm trying to + + + align:start position:0% +I'm coming in here and I'm trying to +help you with what I assume is a problem + + align:start position:0% +help you with what I assume is a problem + + + align:start position:0% +help you with what I assume is a problem +you know it's good to interact and get + + align:start position:0% +you know it's good to interact and get + + + align:start position:0% +you know it's good to interact and get +some kind of information from you guys + + align:start position:0% +some kind of information from you guys + + + align:start position:0% +some kind of information from you guys +um and and also I kind of imposed my + + align:start position:0% +um and and also I kind of imposed my + + + align:start position:0% +um and and also I kind of imposed my +value of keeping shoes tied for a long + + align:start position:0% +value of keeping shoes tied for a long + + + align:start position:0% +value of keeping shoes tied for a long +time over what might be a value of ease + + align:start position:0% +time over what might be a value of ease + + + align:start position:0% +time over what might be a value of ease +to tie your shoe or ease to untie your + + align:start position:0% +to tie your shoe or ease to untie your + + + align:start position:0% +to tie your shoe or ease to untie your +shoe or just familiarity or the way the + + align:start position:0% +shoe or just familiarity or the way the + + + align:start position:0% +shoe or just familiarity or the way the +knot looks you like the way it looks so + + align:start position:0% +knot looks you like the way it looks so + + + align:start position:0% +knot looks you like the way it looks so +you're going to tie the bunny ears over + + align:start position:0% +you're going to tie the bunny ears over + + + align:start position:0% +you're going to tie the bunny ears over +some other not right so I kind of just + + align:start position:0% +some other not right so I kind of just + + + align:start position:0% +some other not right so I kind of just +assumed all these things and just put + + align:start position:0% +assumed all these things and just put + + + align:start position:0% +assumed all these things and just put +them on you and said hey here's a better + + align:start position:0% +them on you and said hey here's a better + + + align:start position:0% +them on you and said hey here's a better +way of doing + + align:start position:0% +way of doing + + + align:start position:0% +way of doing +it so I wanted to use it as a simple + + align:start position:0% +it so I wanted to use it as a simple + + + align:start position:0% +it so I wanted to use it as a simple +illustration of some circumstances you + + align:start position:0% +illustration of some circumstances you + + + align:start position:0% +illustration of some circumstances you +might find yourself in going to + + align:start position:0% +might find yourself in going to + + + align:start position:0% +might find yourself in going to +Nicaragua soon um when you're working + + align:start position:0% +Nicaragua soon um when you're working + + + align:start position:0% +Nicaragua soon um when you're working +with uh people there on the projects + + align:start position:0% +with uh people there on the projects + + + align:start position:0% +with uh people there on the projects +that you've you've been working on so + + align:start position:0% +that you've you've been working on so + + + align:start position:0% +that you've you've been working on so +far where you're going into an entirely + + align:start position:0% +far where you're going into an entirely + + + align:start position:0% +far where you're going into an entirely +different culture right working in + + align:start position:0% +different culture right working in + + + align:start position:0% +different culture right working in +communities where you really don't know + + align:start position:0% +communities where you really don't know + + + align:start position:0% +communities where you really don't know +how everything works um and it it'd be + + align:start position:0% +how everything works um and it it'd be + + + align:start position:0% +how everything works um and it it'd be +really easy to come across in these same + + align:start position:0% +really easy to come across in these same + + + align:start position:0% +really easy to come across in these same +kinds of ways um so I wanted to just + + align:start position:0% +kinds of ways um so I wanted to just + + + align:start position:0% +kinds of ways um so I wanted to just +take a minute if we can to divide up + + align:start position:0% +take a minute if we can to divide up + + + align:start position:0% +take a minute if we can to divide up +into the teams right you guys have been + + align:start position:0% +into the teams right you guys have been + + + align:start position:0% +into the teams right you guys have been +working in teams um and just talk about + + align:start position:0% +working in teams um and just talk about + + + align:start position:0% +working in teams um and just talk about +how you might approach a situation where + + align:start position:0% +how you might approach a situation where + + + align:start position:0% +how you might approach a situation where +you show up to a community you have a + + align:start position:0% +you show up to a community you have a + + + align:start position:0% +you show up to a community you have a +community partner and you know you have + + align:start position:0% +community partner and you know you have + + + align:start position:0% +community partner and you know you have +the project that you've been working on + + align:start position:0% +the project that you've been working on + + + align:start position:0% +the project that you've been working on +all + + align:start position:0% +all + + + align:start position:0% +all +term and um guess how would you go about + + align:start position:0% +term and um guess how would you go about + + + align:start position:0% +term and um guess how would you go about +approaching the situation where you just + + align:start position:0% +approaching the situation where you just + + + align:start position:0% +approaching the situation where you just +show up you get out of the van or you + + align:start position:0% +show up you get out of the van or you + + + align:start position:0% +show up you get out of the van or you +get off the back of the truck and you're + + align:start position:0% +get off the back of the truck and you're + + + align:start position:0% +get off the back of the truck and you're +all right you show up + + align:start position:0% +all right you show up + + + align:start position:0% +all right you show up +up what do you do how do you approach + + align:start position:0% +up what do you do how do you approach + + + align:start position:0% +up what do you do how do you approach +the the leaders that you interact with + + align:start position:0% +the the leaders that you interact with + + + align:start position:0% +the the leaders that you interact with +or just the the people there um and so I + + align:start position:0% +or just the the people there um and so I + + + align:start position:0% +or just the the people there um and so I +I remember last year we had about four + + align:start position:0% +I remember last year we had about four + + + align:start position:0% +I remember last year we had about four +teams or so this's three okay so three + + align:start position:0% +teams or so this's three okay so three + + + align:start position:0% +teams or so this's three okay so three +teams that actually works perfectly um + + align:start position:0% +teams that actually works perfectly um + + + align:start position:0% +teams that actually works perfectly um +and right before we do this I'll + + align:start position:0% +and right before we do this I'll + + + align:start position:0% +and right before we do this I'll +introduce myself a little more I'm Steve + + align:start position:0% +introduce myself a little more I'm Steve + + + align:start position:0% +introduce myself a little more I'm Steve +Ray I know some some of you I'm a PhD + + align:start position:0% +Ray I know some some of you I'm a PhD + + + align:start position:0% +Ray I know some some of you I'm a PhD +suud mechanical engineer here and helped + + align:start position:0% +suud mechanical engineer here and helped + + + align:start position:0% +suud mechanical engineer here and helped +out with DB energy last year uh but in + + align:start position:0% +out with DB energy last year uh but in + + + align:start position:0% +out with DB energy last year uh but in +order to graduate I need to spend a + + align:start position:0% +order to graduate I need to spend a + + + align:start position:0% +order to graduate I need to spend a +little more time on my dissert ation + + align:start position:0% +little more time on my dissert ation + + + align:start position:0% +little more time on my dissert ation +this year so I couldn't help out more + + align:start position:0% +this year so I couldn't help out more + + + align:start position:0% +this year so I couldn't help out more +than this um but yeah that's it I went + + align:start position:0% +than this um but yeah that's it I went + + + align:start position:0% +than this um but yeah that's it I went +to to nicod last year and it was a great + + align:start position:0% +to to nicod last year and it was a great + + + align:start position:0% +to to nicod last year and it was a great +time so you guys should be pumped you + + align:start position:0% +time so you guys should be pumped you + + + align:start position:0% +time so you guys should be pumped you +leave like Friday or Saturday Sunday + + align:start position:0% +leave like Friday or Saturday Sunday + + + align:start position:0% +leave like Friday or Saturday Sunday +Sunday Okay cool so let's just break up + + align:start position:0% +Sunday Okay cool so let's just break up + + + align:start position:0% +Sunday Okay cool so let's just break up +and then we can quickly talk about it + + align:start position:0% +and then we can quickly talk about it + + + align:start position:0% +and then we can quickly talk about it +and the three of us will kind of just + + align:start position:0% +and the three of us will kind of just + + + align:start position:0% +and the three of us will kind of just +help facilitate and help you guys think + + align:start position:0% +help facilitate and help you guys think + + + align:start position:0% +help facilitate and help you guys think +about how you could kind of approach + + align:start position:0% +about how you could kind of approach + + + align:start position:0% +about how you could kind of approach +this in a in a positive way I just want + + align:start position:0% +this in a in a positive way I just want + + + align:start position:0% +this in a in a positive way I just want +to mention that the twoo timeing I think + + align:start position:0% +to mention that the twoo timeing I think + + + align:start position:0% +to mention that the twoo timeing I think +it's very comparable to cooking so you + + align:start position:0% +it's very comparable to cooking so you + + + align:start position:0% +it's very comparable to cooking so you +guys have been cook chewing tin your + + align:start position:0% +guys have been cook chewing tin your + + + align:start position:0% +guys have been cook chewing tin your +shoes since kindergarten is and most + + align:start position:0% +shoes since kindergarten is and most + + + align:start position:0% +shoes since kindergarten is and most +people have been in the kitchen since + + align:start position:0% +people have been in the kitchen since + + + align:start position:0% +people have been in the kitchen since +before they could walk um and cooking + + align:start position:0% +before they could walk um and cooking + + + align:start position:0% +before they could walk um and cooking +you know from seven or8 years old and so + + align:start position:0% +you know from seven or8 years old and so + + + align:start position:0% +you know from seven or8 years old and so +coming in and saying you're cooking + + align:start position:0% +coming in and saying you're cooking + + + align:start position:0% +coming in and saying you're cooking +wrong um which is somewhat what some of + + align:start position:0% +wrong um which is somewhat what some of + + + align:start position:0% +wrong um which is somewhat what some of +us are saying you know hopefully not the + + align:start position:0% +us are saying you know hopefully not the + + + align:start position:0% +us are saying you know hopefully not the +EXP um but fundamentally suggesting + + align:start position:0% +EXP um but fundamentally suggesting + + + align:start position:0% +EXP um but fundamentally suggesting +changes is comparable that you know like + + align:start position:0% +changes is comparable that you know like + + + align:start position:0% +changes is comparable that you know like +it sounds ludicrous and what are you + + align:start position:0% +it sounds ludicrous and what are you + + + align:start position:0% +it sounds ludicrous and what are you +talking about + + align:start position:0% +talking about + + + align:start position:0% +talking about +yeah and sometimes if there's like a + + align:start position:0% +yeah and sometimes if there's like a + + + align:start position:0% +yeah and sometimes if there's like a +something that's relatively new you + + align:start position:0% +something that's relatively new you + + + align:start position:0% +something that's relatively new you +might not even be aware of the problems + + align:start position:0% +might not even be aware of the problems + + + align:start position:0% +might not even be aware of the problems +with it because you've just been doing + + align:start position:0% +with it because you've just been doing + + + align:start position:0% +with it because you've just been doing +it the same way the whole time um so if + + align:start position:0% +it the same way the whole time um so if + + + align:start position:0% +it the same way the whole time um so if +You observe something and they and you + + align:start position:0% +You observe something and they and you + + + align:start position:0% +You observe something and they and you +ask them you have any problems with this + + align:start position:0% +ask them you have any problems with this + + + align:start position:0% +ask them you have any problems with this +so things you can improve and they say h + + align:start position:0% +so things you can improve and they say h + + + align:start position:0% +so things you can improve and they say h +not really like it works pretty well and + + align:start position:0% +not really like it works pretty well and + + + align:start position:0% +not really like it works pretty well and +if you see things that are that you + + align:start position:0% +if you see things that are that you + + + align:start position:0% +if you see things that are that you +think could be improved you could ask + + align:start position:0% +think could be improved you could ask + + + align:start position:0% +think could be improved you could ask +them well you know what do you think + + align:start position:0% +them well you know what do you think + + + align:start position:0% +them well you know what do you think +about decreasing the time for this to to + + align:start position:0% +about decreasing the time for this to to + + + align:start position:0% +about decreasing the time for this to to +work by making this change or something + + align:start position:0% +work by making this change or something + + + align:start position:0% +work by making this change or something +like that where um you it might not be + + align:start position:0% +like that where um you it might not be + + + align:start position:0% +like that where um you it might not be +totally apparent but you can still ask + + align:start position:0% +totally apparent but you can still ask + + + align:start position:0% +totally apparent but you can still ask +him how they would view + + align:start position:0% +him how they would view + + + align:start position:0% +him how they would view +it but starting with what they see is + + align:start position:0% + + + + align:start position:0% + +huge really + + align:start position:0% + + + + align:start position:0% + +proud being cutting carefully there so + + align:start position:0% +proud being cutting carefully there so + + + align:start position:0% +proud being cutting carefully there so +that people be respecting what they've + + align:start position:0% +that people be respecting what they've + + + align:start position:0% +that people be respecting what they've +accomplished while providing + + align:start position:0% +accomplished while providing + + + align:start position:0% +accomplished while providing +positive ideas + + align:start position:0% + + + + align:start position:0% + +for thanks so I know that was kind of + + align:start position:0% +for thanks so I know that was kind of + + + align:start position:0% +for thanks so I know that was kind of +bizarre and weird but um for some of the + + align:start position:0% +bizarre and weird but um for some of the + + + align:start position:0% +bizarre and weird but um for some of the +communities they sort of walking in + + align:start position:0% +communities they sort of walking in + + + align:start position:0% +communities they sort of walking in +while they're going about their daily + + align:start position:0% +while they're going about their daily + + + align:start position:0% +while they're going about their daily +lives and getting completely interrupted + + align:start position:0% +lives and getting completely interrupted + + + align:start position:0% +lives and getting completely interrupted +so that you could talk to them um and so + + align:start position:0% +so that you could talk to them um and so + + + align:start position:0% +so that you could talk to them um and so +just thinking about how awkward and + + align:start position:0% +just thinking about how awkward and + + + align:start position:0% +just thinking about how awkward and +weird that felt and therefore what you + + align:start position:0% +weird that felt and therefore what you + + + align:start position:0% +weird that felt and therefore what you +can do that wasn't like what Steve did + + align:start position:0% +can do that wasn't like what Steve did + + + align:start position:0% +can do that wasn't like what Steve did +because he was definitely doing worst + + align:start position:0% +because he was definitely doing worst + + + align:start position:0% +because he was definitely doing worst +case scenario in order to minimize that + + align:start position:0% +case scenario in order to minimize that + + + align:start position:0% +case scenario in order to minimize that +awkwardness and weirdness + + align:start position:0% +awkwardness and weirdness + + + align:start position:0% +awkwardness and weirdness +um so back to solar + + align:start position:0% +um so back to solar + + + align:start position:0% +um so back to solar +cookers uh so yeah so we're talking + + align:start position:0% +cookers uh so yeah so we're talking + + + align:start position:0% +cookers uh so yeah so we're talking +about the concentrator it can be so hot + + align:start position:0% +about the concentrator it can be so hot + + + align:start position:0% +about the concentrator it can be so hot +as to be dangerous especially for kids + + align:start position:0% +as to be dangerous especially for kids + + + align:start position:0% +as to be dangerous especially for kids +but really for everyone um you can see + + align:start position:0% +but really for everyone um you can see + + + align:start position:0% +but really for everyone um you can see +that is a big wind catcher so they can + + align:start position:0% +that is a big wind catcher so they can + + + align:start position:0% +that is a big wind catcher so they can +blow over pretty easily that's actually + + align:start position:0% +blow over pretty easily that's actually + + + align:start position:0% +blow over pretty easily that's actually +an issue with the group of Phoenix uh + + align:start position:0% +an issue with the group of Phoenix uh + + + align:start position:0% +an issue with the group of Phoenix uh +silic cookers too because this panel is + + align:start position:0% +silic cookers too because this panel is + + + align:start position:0% +silic cookers too because this panel is +so big that it catches in the wind um + + align:start position:0% +so big that it catches in the wind um + + + align:start position:0% +so big that it catches in the wind um +and then you C it's there's also a risk + + align:start position:0% +and then you C it's there's also a risk + + + align:start position:0% +and then you C it's there's also a risk +of when you're stirring spilling food + + align:start position:0% +of when you're stirring spilling food + + + align:start position:0% +of when you're stirring spilling food +onto the reflector and then damaging the + + align:start position:0% +onto the reflector and then damaging the + + + align:start position:0% +onto the reflector and then damaging the +reflector and how well it works so + + align:start position:0% +reflector and how well it works so + + + align:start position:0% +reflector and how well it works so +there's some real drawbacks from the + + align:start position:0% +there's some real drawbacks from the + + + align:start position:0% +there's some real drawbacks from the +parabolic from the greenhouse um it's a + + align:start position:0% +parabolic from the greenhouse um it's a + + + align:start position:0% +parabolic from the greenhouse um it's a +lower temperature and so you can really + + align:start position:0% +lower temperature and so you can really + + + align:start position:0% +lower temperature and so you can really +only cook certain things um but there's + + align:start position:0% +only cook certain things um but there's + + + align:start position:0% +only cook certain things um but there's +no burning happening and you really + + align:start position:0% +no burning happening and you really + + + align:start position:0% +no burning happening and you really +don't need to pay much attention to it + + align:start position:0% +don't need to pay much attention to it + + + align:start position:0% +don't need to pay much attention to it +apart from adjusting the the angle to + + align:start position:0% +apart from adjusting the the angle to + + + align:start position:0% +apart from adjusting the the angle to +the sun + + align:start position:0% +the sun + + + align:start position:0% +the sun +um and then the combo has some of the + + align:start position:0% +um and then the combo has some of the + + + align:start position:0% +um and then the combo has some of the +pros and some of the cons of the + + align:start position:0% +pros and some of the cons of the + + + align:start position:0% +pros and some of the cons of the +others uh so we talked about the + + align:start position:0% +others uh so we talked about the + + + align:start position:0% +others uh so we talked about the +benefits are pretty um oh and the other + + align:start position:0% +benefits are pretty um oh and the other + + + align:start position:0% +benefits are pretty um oh and the other +thing here is like you really can't stir + + align:start position:0% +thing here is like you really can't stir + + + align:start position:0% +thing here is like you really can't stir +this right because as soon as you open + + align:start position:0% +this right because as soon as you open + + + align:start position:0% +this right because as soon as you open +it up uh you you're losing all your your + + align:start position:0% +it up uh you you're losing all your your + + + align:start position:0% +it up uh you you're losing all your your +heat and you have to start all over + + align:start position:0% +heat and you have to start all over + + + align:start position:0% +heat and you have to start all over +again so it's it's a challenging device + + align:start position:0% +again so it's it's a challenging device + + + align:start position:0% +again so it's it's a challenging device +the uh so boxes are made out of almost + + align:start position:0% +the uh so boxes are made out of almost + + + align:start position:0% +the uh so boxes are made out of almost +anything like I've seen plastic I've + + align:start position:0% +anything like I've seen plastic I've + + + align:start position:0% +anything like I've seen plastic I've +seen wood I've seen metal so yeah um so + + align:start position:0% +seen wood I've seen metal so yeah um so + + + align:start position:0% +seen wood I've seen metal so yeah um so +so some of the challenges that people + + align:start position:0% +so some of the challenges that people + + + align:start position:0% +so some of the challenges that people +can be frustrated about in addition so + + align:start position:0% +can be frustrated about in addition so + + + align:start position:0% +can be frustrated about in addition so +one is that you have to cook outdoors + + align:start position:0% +one is that you have to cook outdoors + + + align:start position:0% +one is that you have to cook outdoors +and so in cultures where cooking indoors + + align:start position:0% +and so in cultures where cooking indoors + + + align:start position:0% +and so in cultures where cooking indoors +is standard cooking Outdoors po poses a + + align:start position:0% +is standard cooking Outdoors po poses a + + + align:start position:0% +is standard cooking Outdoors po poses a +lot of challenges so one is just the + + align:start position:0% +lot of challenges so one is just the + + + align:start position:0% +lot of challenges so one is just the +need for privacy another is just risks + + align:start position:0% +need for privacy another is just risks + + + align:start position:0% +need for privacy another is just risks +of theft of either your food and or your + + align:start position:0% +of theft of either your food and or your + + + align:start position:0% +of theft of either your food and or your +cooker um and it's also for people who + + align:start position:0% +cooker um and it's also for people who + + + align:start position:0% +cooker um and it's also for people who +are used to cooking around a fire it's a + + align:start position:0% +are used to cooking around a fire it's a + + + align:start position:0% +are used to cooking around a fire it's a +little less social uh or can be and so + + align:start position:0% +little less social uh or can be and so + + + align:start position:0% +little less social uh or can be and so +that can be a flip side of frust ation + + align:start position:0% +that can be a flip side of frust ation + + + align:start position:0% +that can be a flip side of frust ation +um the super affordable ones like this + + align:start position:0% +um the super affordable ones like this + + + align:start position:0% +um the super affordable ones like this +one is made out of cardboard and so they + + align:start position:0% +one is made out of cardboard and so they + + + align:start position:0% +one is made out of cardboard and so they +don't last very long CU termites tend to + + align:start position:0% +don't last very long CU termites tend to + + + align:start position:0% +don't last very long CU termites tend to +eat them or other + + align:start position:0% +eat them or other + + + align:start position:0% +eat them or other +insects uh but they're very inexpensive + + align:start position:0% +insects uh but they're very inexpensive + + + align:start position:0% +insects uh but they're very inexpensive +um and then they use a plastic bag just + + align:start position:0% +um and then they use a plastic bag just + + + align:start position:0% +um and then they use a plastic bag just +as your cover for your greenhouse and + + align:start position:0% +as your cover for your greenhouse and + + + align:start position:0% +as your cover for your greenhouse and +again very inexpensive but pretty short + + align:start position:0% +again very inexpensive but pretty short + + + align:start position:0% +again very inexpensive but pretty short +life um and so then you have with all + + align:start position:0% +life um and so then you have with all + + + align:start position:0% +life um and so then you have with all +these things breaking down and you have + + align:start position:0% +these things breaking down and you have + + + align:start position:0% +these things breaking down and you have +a supply chain issue of you need to make + + align:start position:0% +a supply chain issue of you need to make + + + align:start position:0% +a supply chain issue of you need to make +sure that people are able to get + + align:start position:0% +sure that people are able to get + + + align:start position:0% +sure that people are able to get +Replacements um and able to afford + + align:start position:0% +Replacements um and able to afford + + + align:start position:0% +Replacements um and able to afford +replacement + + align:start position:0% +replacement + + + align:start position:0% +replacement +um the size often times uh I sort of + + align:start position:0% +um the size often times uh I sort of + + + align:start position:0% +um the size often times uh I sort of +gave you a hard time Carter about the + + align:start position:0% +gave you a hard time Carter about the + + + align:start position:0% +gave you a hard time Carter about the +size thing um but it's true that + + align:start position:0% +size thing um but it's true that + + + align:start position:0% +size thing um but it's true that +actually a lot of the times they're + + align:start position:0% +actually a lot of the times they're + + + align:start position:0% +actually a lot of the times they're +relatively small for how much they can + + align:start position:0% +relatively small for how much they can + + + align:start position:0% +relatively small for how much they can +cook and so you can't always cook for + + align:start position:0% +cook and so you can't always cook for + + + align:start position:0% +cook and so you can't always cook for +all of your family members that's + + align:start position:0% +all of your family members that's + + + align:start position:0% +all of your family members that's +frustrating there was an interesting + + align:start position:0% +frustrating there was an interesting + + + align:start position:0% +frustrating there was an interesting +sort of case study where solar cookers + + align:start position:0% +sort of case study where solar cookers + + + align:start position:0% +sort of case study where solar cookers +were brought uh to kakuma which is a + + align:start position:0% +were brought uh to kakuma which is a + + + align:start position:0% +were brought uh to kakuma which is a +Kenyon refugee camp for uh refugees from + + align:start position:0% +Kenyon refugee camp for uh refugees from + + + align:start position:0% +Kenyon refugee camp for uh refugees from +the Sudan and the solar cookers + + align:start position:0% +the Sudan and the solar cookers + + + align:start position:0% +the Sudan and the solar cookers +International gave away a bunch of + + align:start position:0% +International gave away a bunch of + + + align:start position:0% +International gave away a bunch of +cookers + + align:start position:0% +cookers + + + align:start position:0% +cookers +and they it was it actually this cooker + + align:start position:0% +and they it was it actually this cooker + + + align:start position:0% +and they it was it actually this cooker +right here and um so they people were + + align:start position:0% +right here and um so they people were + + + align:start position:0% +right here and um so they people were +getting their solar cookers for free and + + align:start position:0% +getting their solar cookers for free and + + + align:start position:0% +getting their solar cookers for free and +cooking was a huge issue in these + + align:start position:0% +cooking was a huge issue in these + + + align:start position:0% +cooking was a huge issue in these +refugee camps because women were having + + align:start position:0% +refugee camps because women were having + + + align:start position:0% +refugee camps because women were having +to leave the camp in order to get + + align:start position:0% +to leave the camp in order to get + + + align:start position:0% +to leave the camp in order to get +firewood and when they were they were + + align:start position:0% +firewood and when they were they were + + + align:start position:0% +firewood and when they were they were +regularly raped and so they needed an + + align:start position:0% +regularly raped and so they needed an + + + align:start position:0% +regularly raped and so they needed an +alternative um pretty sever severely + + align:start position:0% +alternative um pretty sever severely + + + align:start position:0% +alternative um pretty sever severely +because there was no safe option for + + align:start position:0% +because there was no safe option for + + + align:start position:0% +because there was no safe option for +cooking and they also were spending over + + align:start position:0% +cooking and they also were spending over + + + align:start position:0% +cooking and they also were spending over +50% of their income on firewood um if + + align:start position:0% +50% of their income on firewood um if + + + align:start position:0% +50% of their income on firewood um if +they were buying it uh so really + + align:start position:0% +they were buying it uh so really + + + align:start position:0% +they were buying it uh so really +outrageous and in the end what they + + align:start position:0% +outrageous and in the end what they + + + align:start position:0% +outrageous and in the end what they +found is that less than 20% of people + + align:start position:0% +found is that less than 20% of people + + + align:start position:0% +found is that less than 20% of people +ended up using the solar cookers more + + align:start position:0% +ended up using the solar cookers more + + + align:start position:0% +ended up using the solar cookers more +than one or two days per week so that's + + align:start position:0% +than one or two days per week so that's + + + align:start position:0% +than one or two days per week so that's +a pretty low rate of usage um for + + align:start position:0% +a pretty low rate of usage um for + + + align:start position:0% +a pretty low rate of usage um for +something when you're facing really + + align:start position:0% +something when you're facing really + + + align:start position:0% +something when you're facing really +severe costs either to your bodily + + align:start position:0% +severe costs either to your bodily + + + align:start position:0% +severe costs either to your bodily +well-being or your income um that severe + + align:start position:0% +well-being or your income um that severe + + + align:start position:0% +well-being or your income um that severe +so I think that speaks to the challenges + + align:start position:0% +so I think that speaks to the challenges + + + align:start position:0% +so I think that speaks to the challenges +of solar cooker adoption that um people + + align:start position:0% +of solar cooker adoption that um people + + + align:start position:0% +of solar cooker adoption that um people +don't love to use them + + align:start position:0% +don't love to use them + + + align:start position:0% +don't love to use them +was that just because they were not used + + align:start position:0% +was that just because they were not used + + + align:start position:0% +was that just because they were not used +to it or were there any major kind of + + align:start position:0% +to it or were there any major kind of + + + align:start position:0% +to it or were there any major kind of +design flaws that made them useless or + + align:start position:0% +design flaws that made them useless or + + + align:start position:0% +design flaws that made them useless or +well so people really don't like them + + align:start position:0% +well so people really don't like them + + + align:start position:0% +well so people really don't like them +like these cookers work um but all these + + align:start position:0% +like these cookers work um but all these + + + align:start position:0% +like these cookers work um but all these +real issues like you can only cook + + align:start position:0% +real issues like you can only cook + + + align:start position:0% +real issues like you can only cook +during Lun for lunch basically you can't + + align:start position:0% +during Lun for lunch basically you can't + + + align:start position:0% +during Lun for lunch basically you can't +cook for breakfast you can't cook for + + align:start position:0% +cook for breakfast you can't cook for + + + align:start position:0% +cook for breakfast you can't cook for +dinner um you can only cook C certain + + align:start position:0% +dinner um you can only cook C certain + + + align:start position:0% +dinner um you can only cook C certain +types of foods etc etc make them a + + align:start position:0% +types of foods etc etc make them a + + + align:start position:0% +types of foods etc etc make them a +really limit of limited value um so on + + align:start position:0% +really limit of limited value um so on + + + align:start position:0% +really limit of limited value um so on +the flip side uh at kakuma is that there + + align:start position:0% +the flip side uh at kakuma is that there + + + align:start position:0% +the flip side uh at kakuma is that there +were a bunch of single men there um who + + align:start position:0% +were a bunch of single men there um who + + + align:start position:0% +were a bunch of single men there um who +were separated from their families so + + align:start position:0% +were separated from their families so + + + align:start position:0% +were separated from their families so +normally um in the + + align:start position:0% +normally um in the + + + align:start position:0% +normally um in the +Sudan I am talking about Sudan yeah um + + align:start position:0% +Sudan I am talking about Sudan yeah um + + + align:start position:0% +Sudan I am talking about Sudan yeah um +in the Sudan um if you're a single guy + + align:start position:0% +in the Sudan um if you're a single guy + + + align:start position:0% +in the Sudan um if you're a single guy +your mom cooks for you and it's not + + align:start position:0% +your mom cooks for you and it's not + + + align:start position:0% +your mom cooks for you and it's not +normal for men to cook at all so either + + align:start position:0% +normal for men to cook at all so either + + + align:start position:0% +normal for men to cook at all so either +your wife or your mom is cooking for you + + align:start position:0% +your wife or your mom is cooking for you + + + align:start position:0% +your wife or your mom is cooking for you +and so these single men were separated + + align:start position:0% +and so these single men were separated + + + align:start position:0% +and so these single men were separated +from their mom so they didn't have + + align:start position:0% +from their mom so they didn't have + + + align:start position:0% +from their mom so they didn't have +anyone to cook with and it was really + + align:start position:0% +anyone to cook with and it was really + + + align:start position:0% +anyone to cook with and it was really +socially inappropriate for them to cook + + align:start position:0% +socially inappropriate for them to cook + + + align:start position:0% +socially inappropriate for them to cook +with wood and so they were actually the + + align:start position:0% +with wood and so they were actually the + + + align:start position:0% +with wood and so they were actually the +adopters who used the solar cookers + + align:start position:0% +adopters who used the solar cookers + + + align:start position:0% +adopters who used the solar cookers +because it was appropriate for them to + + align:start position:0% +because it was appropriate for them to + + + align:start position:0% +because it was appropriate for them to +use these because they're really not + + align:start position:0% +use these because they're really not + + + align:start position:0% +use these because they're really not +considered stoves the way uh firewood + + align:start position:0% +considered stoves the way uh firewood + + + align:start position:0% +considered stoves the way uh firewood +stove would be considered a stove so + + align:start position:0% +stove would be considered a stove so + + + align:start position:0% +stove would be considered a stove so +that was the success story was that when + + align:start position:0% +that was the success story was that when + + + align:start position:0% +that was the success story was that when +you needed a radically different um + + align:start position:0% +you needed a radically different um + + + align:start position:0% +you needed a radically different um +option it was it was relatively well + + align:start position:0% +option it was it was relatively well + + + align:start position:0% +option it was it was relatively well +adopted um so yeah so and the other + + align:start position:0% +adopted um so yeah so and the other + + + align:start position:0% +adopted um so yeah so and the other +aspect is + + align:start position:0% +aspect is + + + align:start position:0% +aspect is +that the in this Camp there was a food + + align:start position:0% +that the in this Camp there was a food + + + align:start position:0% +that the in this Camp there was a food +scarcity also which is unsurprising and + + align:start position:0% +scarcity also which is unsurprising and + + + align:start position:0% +scarcity also which is unsurprising and +so asking people to uh experiment with + + align:start position:0% +so asking people to uh experiment with + + + align:start position:0% +so asking people to uh experiment with +how they cook when they don't know if + + align:start position:0% +how they cook when they don't know if + + + align:start position:0% +how they cook when they don't know if +they have enough food is a huge um + + align:start position:0% +they have enough food is a huge um + + + align:start position:0% +they have enough food is a huge um +request best of people and so I think + + align:start position:0% +request best of people and so I think + + + align:start position:0% +request best of people and so I think +that's part of the reason for the lack + + align:start position:0% +that's part of the reason for the lack + + + align:start position:0% +that's part of the reason for the lack +of adoption was that I'm not willing to + + align:start position:0% +of adoption was that I'm not willing to + + + align:start position:0% +of adoption was that I'm not willing to +try this wacky stove because what if I + + align:start position:0% +try this wacky stove because what if I + + + align:start position:0% +try this wacky stove because what if I +ruin my food that means I don't eat + + align:start position:0% +ruin my food that means I don't eat + + + align:start position:0% +ruin my food that means I don't eat +today and I don't know when I'll be + + align:start position:0% +today and I don't know when I'll be + + + align:start position:0% +today and I don't know when I'll be +eating very much um so that was the the + + align:start position:0% +eating very much um so that was the the + + + align:start position:0% +eating very much um so that was the the +summer summary of solar cookers there + + align:start position:0% +summer summary of solar cookers there + + + align:start position:0% +summer summary of solar cookers there +any questions on solar + + align:start position:0% +any questions on solar + + + align:start position:0% +any questions on solar +cookers I'm sorry I dropped that over + + align:start position:0% +cookers I'm sorry I dropped that over + + + align:start position:0% +cookers I'm sorry I dropped that over +the charcoal lecture that or stove + + align:start position:0% +the charcoal lecture that or stove + + + align:start position:0% +the charcoal lecture that or stove +lecture that would have been the time to + + align:start position:0% +lecture that would have been the time to + + + align:start position:0% +lecture that would have been the time to +do it I don't know how it got lost okay + + align:start position:0% +do it I don't know how it got lost okay + + + align:start position:0% +do it I don't know how it got lost okay +so now we're finally going to talk about + + align:start position:0% +so now we're finally going to talk about + + + align:start position:0% +so now we're finally going to talk about +the trip + + align:start position:0% +the trip + + + align:start position:0% +the trip +a bit um sort of reverting back to what + + align:start position:0% +a bit um sort of reverting back to what + + + align:start position:0% +a bit um sort of reverting back to what +Steve was talking about this lectures a + + align:start position:0% +Steve was talking about this lectures a + + + align:start position:0% +Steve was talking about this lectures a +little bouncing around intentionally so + + align:start position:0% +little bouncing around intentionally so + + + align:start position:0% +little bouncing around intentionally so +that Steve could interrupt us um so uh + + align:start position:0% +that Steve could interrupt us um so uh + + + align:start position:0% +that Steve could interrupt us um so uh +the trip goals are number one to have + + align:start position:0% +the trip goals are number one to have + + + align:start position:0% +the trip goals are number one to have +some well identified well understood and + + align:start position:0% +some well identified well understood and + + + align:start position:0% +some well identified well understood and +well documented projects um ideally + + align:start position:0% +well documented projects um ideally + + + align:start position:0% +well documented projects um ideally +highly relevant to daab energy however + + align:start position:0% +highly relevant to daab energy however + + + align:start position:0% +highly relevant to daab energy however +if you find some that are not at all + + align:start position:0% +if you find some that are not at all + + + align:start position:0% +if you find some that are not at all +energy projects but are seem like + + align:start position:0% +energy projects but are seem like + + + align:start position:0% +energy projects but are seem like +interesting projects we can often take + + align:start position:0% +interesting projects we can often take + + + align:start position:0% +interesting projects we can often take +these projects and feed them into daab + + align:start position:0% +these projects and feed them into daab + + + align:start position:0% +these projects and feed them into daab +design or other daab classes so if you + + align:start position:0% +design or other daab classes so if you + + + align:start position:0% +design or other daab classes so if you +learn about some others feel free to + + align:start position:0% +learn about some others feel free to + + + align:start position:0% +learn about some others feel free to +document them it's really helpful to + + align:start position:0% +document them it's really helpful to + + + align:start position:0% +document them it's really helpful to +daab as a community to have those extra + + align:start position:0% +daab as a community to have those extra + + + align:start position:0% +daab as a community to have those extra +projects um and then we've talked about + + align:start position:0% +projects um and then we've talked about + + + align:start position:0% +projects um and then we've talked about +a few projects for you guys there may be + + align:start position:0% +a few projects for you guys there may be + + + align:start position:0% +a few projects for you guys there may be +others that come up that are either + + align:start position:0% +others that come up that are either + + + align:start position:0% +others that come up that are either +ideal for you to work on this semester + + align:start position:0% +ideal for you to work on this semester + + + align:start position:0% +ideal for you to work on this semester +and that's fine to change course like + + align:start position:0% +and that's fine to change course like + + + align:start position:0% +and that's fine to change course like +that and or for you to um for future + + align:start position:0% +that and or for you to um for future + + + align:start position:0% +that and or for you to um for future +generations of DB energy students to + + align:start position:0% +generations of DB energy students to + + + align:start position:0% +generations of DB energy students to +work on so please document any projects + + align:start position:0% +work on so please document any projects + + + align:start position:0% +work on so please document any projects +you come across um and I will be getting + + align:start position:0% +you come across um and I will be getting + + + align:start position:0% +you come across um and I will be getting +you on Friday the sheet of how to + + align:start position:0% +you on Friday the sheet of how to + + + align:start position:0% +you on Friday the sheet of how to +document so that you have a good sense + + align:start position:0% +document so that you have a good sense + + + align:start position:0% +document so that you have a good sense +of what information you need to gather + + align:start position:0% +of what information you need to gather + + + align:start position:0% +of what information you need to gather +but hopefully we're also getting that + + align:start position:0% +but hopefully we're also getting that + + + align:start position:0% +but hopefully we're also getting that +today um second is to really understand + + align:start position:0% +today um second is to really understand + + + align:start position:0% +today um second is to really understand +the communities are working in so you + + align:start position:0% +the communities are working in so you + + + align:start position:0% +the communities are working in so you +can do a good job of Designing with and + + align:start position:0% +can do a good job of Designing with and + + + align:start position:0% +can do a good job of Designing with and +for them um what are their needs what + + align:start position:0% +for them um what are their needs what + + + align:start position:0% +for them um what are their needs what +are their finances what is their health + + align:start position:0% +are their finances what is their health + + + align:start position:0% +are their finances what is their health +their education culture government um + + align:start position:0% +their education culture government um + + + align:start position:0% +their education culture government um +both you know less critically though + + align:start position:0% +both you know less critically though + + + align:start position:0% +both you know less critically though +some somewhat critically in terms of + + align:start position:0% +some somewhat critically in terms of + + + align:start position:0% +some somewhat critically in terms of +understanding when grids arrive the + + align:start position:0% +understanding when grids arrive the + + + align:start position:0% +understanding when grids arrive the +formal government but also like the + + align:start position:0% +formal government but also like the + + + align:start position:0% +formal government but also like the +informal Community government that + + align:start position:0% +informal Community government that + + + align:start position:0% +informal Community government that +exists um and along those lines formal + + align:start position:0% +exists um and along those lines formal + + + align:start position:0% +exists um and along those lines formal +informal leaders Lifestyles um work etc + + align:start position:0% +informal leaders Lifestyles um work etc + + + align:start position:0% +informal leaders Lifestyles um work etc +and then doing the charcoal trainings SL + + align:start position:0% +and then doing the charcoal trainings SL + + + align:start position:0% +and then doing the charcoal trainings SL +creative capacity building as + + align:start position:0% +creative capacity building as + + + align:start position:0% +creative capacity building as +appropriate so I want to talk a little + + align:start position:0% +appropriate so I want to talk a little + + + align:start position:0% +appropriate so I want to talk a little +bit about creative capacity building + + align:start position:0% +bit about creative capacity building + + + align:start position:0% +bit about creative capacity building +which is a term that Amy Smith coined + + align:start position:0% +which is a term that Amy Smith coined + + + align:start position:0% +which is a term that Amy Smith coined +for the way that she um hopes that all + + align:start position:0% +for the way that she um hopes that all + + + align:start position:0% +for the way that she um hopes that all +daab groups can work so I want to talk + + align:start position:0% +daab groups can work so I want to talk + + + align:start position:0% +daab groups can work so I want to talk +about what she did um at a refugee camp + + align:start position:0% +about what she did um at a refugee camp + + + align:start position:0% +about what she did um at a refugee camp +in Uganda as an example uh so this is a + + align:start position:0% +in Uganda as an example uh so this is a + + + align:start position:0% +in Uganda as an example uh so this is a +relief camp for refugees in Uganda it + + align:start position:0% +relief camp for refugees in Uganda it + + + align:start position:0% +relief camp for refugees in Uganda it +looks kind of picturesque but each one + + align:start position:0% +looks kind of picturesque but each one + + + align:start position:0% +looks kind of picturesque but each one +of those Huts uh is about 10 or 12 ft in + + align:start position:0% +of those Huts uh is about 10 or 12 ft in + + + align:start position:0% +of those Huts uh is about 10 or 12 ft in +diameter and houses 20 people generally + + align:start position:0% +diameter and houses 20 people generally + + + align:start position:0% +diameter and houses 20 people generally +and they've been living there for 20 to + + align:start position:0% +and they've been living there for 20 to + + + align:start position:0% +and they've been living there for 20 to +30 years um so there's plenty of people + + align:start position:0% +30 years um so there's plenty of people + + + align:start position:0% +30 years um so there's plenty of people +who have grown up in this refugee camp + + align:start position:0% +who have grown up in this refugee camp + + + align:start position:0% +who have grown up in this refugee camp +um it's their choice is to be there are + + align:start position:0% +um it's their choice is to be there are + + + align:start position:0% +um it's their choice is to be there are +to be completely unsafe if they're not + + align:start position:0% +to be completely unsafe if they're not + + + align:start position:0% +to be completely unsafe if they're not +in the refugee camp um either getting + + align:start position:0% +in the refugee camp um either getting + + + align:start position:0% +in the refugee camp um either getting +killed or getting um enlisted into the + + align:start position:0% +killed or getting um enlisted into the + + + align:start position:0% +killed or getting um enlisted into the +army um and because they're in a camp + + align:start position:0% +army um and because they're in a camp + + + align:start position:0% +army um and because they're in a camp +there's really no natural resources or + + align:start position:0% +there's really no natural resources or + + + align:start position:0% +there's really no natural resources or +ability to do work so there's a real + + align:start position:0% +ability to do work so there's a real + + + align:start position:0% +ability to do work so there's a real +culture of dependency um things are + + align:start position:0% +culture of dependency um things are + + + align:start position:0% +culture of dependency um things are +finally safe enough that this group of + + align:start position:0% +finally safe enough that this group of + + + align:start position:0% +finally safe enough that this group of +people is getting and it's about 100,000 + + align:start position:0% +people is getting and it's about 100,000 + + + align:start position:0% +people is getting and it's about 100,000 +people um group of people is getting + + align:start position:0% +people um group of people is getting + + + align:start position:0% +people um group of people is getting +ready to get repatriated back to um + + align:start position:0% +ready to get repatriated back to um + + + align:start position:0% +ready to get repatriated back to um +their original homes um but people have + + align:start position:0% +their original homes um but people have + + + align:start position:0% +their original homes um but people have +basically lived there their whole lives + + align:start position:0% +basically lived there their whole lives + + + align:start position:0% +basically lived there their whole lives +and so there's this culture of + + align:start position:0% +and so there's this culture of + + + align:start position:0% +and so there's this culture of +dependency how are we going to adjust + + align:start position:0% +dependency how are we going to adjust + + + align:start position:0% +dependency how are we going to adjust +back to home um they're used to a very + + align:start position:0% +back to home um they're used to a very + + + align:start position:0% +back to home um they're used to a very +centralized life in Camp um and + + align:start position:0% +centralized life in Camp um and + + + align:start position:0% +centralized life in Camp um and +adjusting back and especially the burden + + align:start position:0% +adjusting back and especially the burden + + + align:start position:0% +adjusting back and especially the burden +on the women going back is very high + + align:start position:0% +on the women going back is very high + + + align:start position:0% +on the women going back is very high +because all of a sudden they now have to + + align:start position:0% +because all of a sudden they now have to + + + align:start position:0% +because all of a sudden they now have to +be figuring out how to cook all the food + + align:start position:0% +be figuring out how to cook all the food + + + align:start position:0% +be figuring out how to cook all the food +get all the water get all the wood Etc + + align:start position:0% +get all the water get all the wood Etc + + + align:start position:0% +get all the water get all the wood Etc +um and there's been very little capacity + + align:start position:0% +um and there's been very little capacity + + + align:start position:0% +um and there's been very little capacity +building in this Camp up to now um so + + align:start position:0% +building in this Camp up to now um so + + + align:start position:0% +building in this Camp up to now um so +what Amy did when she was invited there + + align:start position:0% +what Amy did when she was invited there + + + align:start position:0% +what Amy did when she was invited there +um was initially do a technology + + align:start position:0% +um was initially do a technology + + + align:start position:0% +um was initially do a technology +demonstration with a sort of classic DB + + align:start position:0% +demonstration with a sort of classic DB + + + align:start position:0% +demonstration with a sort of classic DB +technology which is corn shellers and if + + align:start position:0% +technology which is corn shellers and if + + + align:start position:0% +technology which is corn shellers and if +you're curious about them they're on the + + align:start position:0% +you're curious about them they're on the + + + align:start position:0% +you're curious about them they're on the +back shelf back there so you can check + + align:start position:0% +back shelf back there so you can check + + + align:start position:0% +back shelf back there so you can check +them out but basically + + align:start position:0% + + + + align:start position:0% + +um the corn sheller uh people generally + + align:start position:0% +um the corn sheller uh people generally + + + align:start position:0% +um the corn sheller uh people generally +shell corn by hand it's really labor + + align:start position:0% +shell corn by hand it's really labor + + + align:start position:0% +shell corn by hand it's really labor +intensive and relatively painful to do + + align:start position:0% +intensive and relatively painful to do + + + align:start position:0% +intensive and relatively painful to do +because the corn is dry and it's really + + align:start position:0% +because the corn is dry and it's really + + + align:start position:0% +because the corn is dry and it's really +hard to get off um and so daab + + align:start position:0% +hard to get off um and so daab + + + align:start position:0% +hard to get off um and so daab +identified this injection molded corn + + align:start position:0% +identified this injection molded corn + + + align:start position:0% +identified this injection molded corn +sheller or something that could work in + + align:start position:0% +sheller or something that could work in + + + align:start position:0% +sheller or something that could work in +a lot of communities really well but + + align:start position:0% +a lot of communities really well but + + + align:start position:0% +a lot of communities really well but +it's really hard to injection mold at + + align:start position:0% +it's really hard to injection mold at + + + align:start position:0% +it's really hard to injection mold at +the community level it requires really + + align:start position:0% +the community level it requires really + + + align:start position:0% +the community level it requires really +high pressure and plastic neither of + + align:start position:0% +high pressure and plastic neither of + + + align:start position:0% +high pressure and plastic neither of +which are available and so daab + + align:start position:0% +which are available and so daab + + + align:start position:0% +which are available and so daab +developed two ways of making that corn + + align:start position:0% +developed two ways of making that corn + + + align:start position:0% +developed two ways of making that corn +sheller either by welding or by bending + + align:start position:0% +sheller either by welding or by bending + + + align:start position:0% +sheller either by welding or by bending +sheet metal that are really easy to make + + align:start position:0% +sheet metal that are really easy to make + + + align:start position:0% +sheet metal that are really easy to make +basically anywhere and allow people to + + align:start position:0% +basically anywhere and allow people to + + + align:start position:0% +basically anywhere and allow people to +Shell their own corn very quickly very + + align:start position:0% +Shell their own corn very quickly very + + + align:start position:0% +Shell their own corn very quickly very +affordable + + align:start position:0% +affordable + + + align:start position:0% +affordable +um and people really loved it so they + + align:start position:0% +um and people really loved it so they + + + align:start position:0% +um and people really loved it so they +they really excited um and so this is + + align:start position:0% +they really excited um and so this is + + + align:start position:0% +they really excited um and so this is +Kofi who traveled with Amy and is + + align:start position:0% +Kofi who traveled with Amy and is + + + align:start position:0% +Kofi who traveled with Amy and is +another DB staff member um they taught + + align:start position:0% +another DB staff member um they taught + + + align:start position:0% +another DB staff member um they taught +them how to make their own corn shellers + + align:start position:0% +them how to make their own corn shellers + + + align:start position:0% +them how to make their own corn shellers +and people were really pumped and so + + align:start position:0% +and people were really pumped and so + + + align:start position:0% +and people were really pumped and so +this was both just a tech transfer sort + + align:start position:0% +this was both just a tech transfer sort + + + align:start position:0% +this was both just a tech transfer sort +of like doing a charcoal demonstration + + align:start position:0% +of like doing a charcoal demonstration + + + align:start position:0% +of like doing a charcoal demonstration +I'm teaching you how to make these corn + + align:start position:0% +I'm teaching you how to make these corn + + + align:start position:0% +I'm teaching you how to make these corn +shellers and hopefully you can start + + align:start position:0% +shellers and hopefully you can start + + + align:start position:0% +shellers and hopefully you can start +making them for yourselves and using + + align:start position:0% +making them for yourselves and using + + + align:start position:0% +making them for yourselves and using +them awesome but also to start inspiring + + align:start position:0% +them awesome but also to start inspiring + + + align:start position:0% +them awesome but also to start inspiring +conversation about well what else do you + + align:start position:0% +conversation about well what else do you + + + align:start position:0% +conversation about well what else do you +need and how else could it be how could + + align:start position:0% +need and how else could it be how could + + + align:start position:0% +need and how else could it be how could +those needs be dress together um and so + + align:start position:0% +those needs be dress together um and so + + + align:start position:0% +those needs be dress together um and so +one of the projects that was discussed + + align:start position:0% +one of the projects that was discussed + + + align:start position:0% +one of the projects that was discussed +was uh grinding so grinding their corn + + align:start position:0% +was uh grinding so grinding their corn + + + align:start position:0% +was uh grinding so grinding their corn +this is a traditional grinding stone you + + align:start position:0% +this is a traditional grinding stone you + + + align:start position:0% +this is a traditional grinding stone you +can imagine how hard it is to use this + + align:start position:0% +can imagine how hard it is to use this + + + align:start position:0% +can imagine how hard it is to use this +Stone to successfully grind dried corn + + align:start position:0% +Stone to successfully grind dried corn + + + align:start position:0% +Stone to successfully grind dried corn +um how labor intensive it is and people + + align:start position:0% +um how labor intensive it is and people + + + align:start position:0% +um how labor intensive it is and people +found it uh they also or actually not + + align:start position:0% +found it uh they also or actually not + + + align:start position:0% +found it uh they also or actually not +corn excuse me they grind Sesame and + + align:start position:0% +corn excuse me they grind Sesame and + + + align:start position:0% +corn excuse me they grind Sesame and +groundnuts which are peanuts in it um + + align:start position:0% +groundnuts which are peanuts in it um + + + align:start position:0% +groundnuts which are peanuts in it um +and again it's very labor intensive so + + align:start position:0% +and again it's very labor intensive so + + + align:start position:0% +and again it's very labor intensive so +first so that was the issue posed was + + align:start position:0% +first so that was the issue posed was + + + align:start position:0% +first so that was the issue posed was +how do we grind our our uh Sesame and + + align:start position:0% +how do we grind our our uh Sesame and + + + align:start position:0% +how do we grind our our uh Sesame and +peanuts more easily and so first they + + align:start position:0% +peanuts more easily and so first they + + + align:start position:0% +peanuts more easily and so first they +looked at what the commercial method is + + align:start position:0% +looked at what the commercial method is + + + align:start position:0% +looked at what the commercial method is +in that area is a commercial grinder + + align:start position:0% +in that area is a commercial grinder + + + align:start position:0% +in that area is a commercial grinder +which requires diesel um and is totally + + align:start position:0% +which requires diesel um and is totally + + + align:start position:0% +which requires diesel um and is totally +unaffordable for this community so they + + align:start position:0% +unaffordable for this community so they + + + align:start position:0% +unaffordable for this community so they +said all right that's not going to work + + align:start position:0% +said all right that's not going to work + + + align:start position:0% +said all right that's not going to work +so let's design our own and so in a day + + align:start position:0% +so let's design our own and so in a day + + + align:start position:0% +so let's design our own and so in a day +they found a meat grinder and put + + align:start position:0% +they found a meat grinder and put + + + align:start position:0% +they found a meat grinder and put +together this really basic crappy + + align:start position:0% +together this really basic crappy + + + align:start position:0% +together this really basic crappy +prototype um and partly it was crappy + + align:start position:0% +prototype um and partly it was crappy + + + align:start position:0% +prototype um and partly it was crappy +because they had a day and partly was is + + align:start position:0% +because they had a day and partly was is + + + align:start position:0% +because they had a day and partly was is +cra happy intentionally because they + + align:start position:0% +cra happy intentionally because they + + + align:start position:0% +cra happy intentionally because they +built this with Community Partners um + + align:start position:0% +built this with Community Partners um + + + align:start position:0% +built this with Community Partners um +Amy and Kofi really took the lead but + + align:start position:0% +Amy and Kofi really took the lead but + + + align:start position:0% +Amy and Kofi really took the lead but +working very closely with the local + + align:start position:0% +working very closely with the local + + + align:start position:0% +working very closely with the local +Builders as well as the local people and + + align:start position:0% +Builders as well as the local people and + + + align:start position:0% +Builders as well as the local people and +so people got a really good sense of how + + align:start position:0% +so people got a really good sense of how + + + align:start position:0% +so people got a really good sense of how +one could develop this project really + + align:start position:0% +one could develop this project really + + + align:start position:0% +one could develop this project really +fast without the fancy MIT education + + align:start position:0% +fast without the fancy MIT education + + + align:start position:0% +fast without the fancy MIT education +that Amy brings to the table but just + + align:start position:0% +that Amy brings to the table but just + + + align:start position:0% +that Amy brings to the table but just +they got their head around oh this is + + align:start position:0% +they got their head around oh this is + + + align:start position:0% +they got their head around oh this is +how I could do this and got really + + align:start position:0% +how I could do this and got really + + + align:start position:0% +how I could do this and got really +excited and they also saw how relatively + + align:start position:0% +excited and they also saw how relatively + + + align:start position:0% +excited and they also saw how relatively +crappy this was and how there need to be + + align:start position:0% +crappy this was and how there need to be + + + align:start position:0% +crappy this was and how there need to be +improvements and so they started saying + + align:start position:0% +improvements and so they started saying + + + align:start position:0% +improvements and so they started saying +things like when I build mine I'm going + + align:start position:0% +things like when I build mine I'm going + + + align:start position:0% +things like when I build mine I'm going +to do this which is a really good + + align:start position:0% +to do this which is a really good + + + align:start position:0% +to do this which is a really good +indicator that they're now feeling + + align:start position:0% +indicator that they're now feeling + + + align:start position:0% +indicator that they're now feeling +empowered to build their own rather than + + align:start position:0% +empowered to build their own rather than + + + align:start position:0% +empowered to build their own rather than +when you come back and build me another + + align:start position:0% +when you come back and build me another + + + align:start position:0% +when you come back and build me another +one it's going to look like this right + + align:start position:0% +one it's going to look like this right + + + align:start position:0% +one it's going to look like this right +and that's that's the goal is right when + + align:start position:0% +and that's that's the goal is right when + + + align:start position:0% +and that's that's the goal is right when +I build mine rather than when you come + + align:start position:0% +I build mine rather than when you come + + + align:start position:0% +I build mine rather than when you come +back and Build Me Mine uh so people got + + align:start position:0% +back and Build Me Mine uh so people got + + + align:start position:0% +back and Build Me Mine uh so people got +really excited um and just tried it out + + align:start position:0% +really excited um and just tried it out + + + align:start position:0% +really excited um and just tried it out +um and it was a great + + align:start position:0% +um and it was a great + + + align:start position:0% +um and it was a great +outcome so uh this sort of experience + + align:start position:0% +outcome so uh this sort of experience + + + align:start position:0% +outcome so uh this sort of experience +helped Amy solidify her thinking about + + align:start position:0% +helped Amy solidify her thinking about + + + align:start position:0% +helped Amy solidify her thinking about +creative capacity building which is + + align:start position:0% +creative capacity building which is + + + align:start position:0% +creative capacity building which is +we're not there for just for Tex + + align:start position:0% +we're not there for just for Tex + + + align:start position:0% +we're not there for just for Tex +transfer we're not there just to + + align:start position:0% +transfer we're not there just to + + + align:start position:0% +transfer we're not there just to +identify problems and then come back to + + align:start position:0% +identify problems and then come back to + + + align:start position:0% +identify problems and then come back to +MIT and fix them but working with people + + align:start position:0% +MIT and fix them but working with people + + + align:start position:0% +MIT and fix them but working with people +side by side through all areas of the + + align:start position:0% +side by side through all areas of the + + + align:start position:0% +side by side through all areas of the +design process to help them develop + + align:start position:0% +design process to help them develop + + + align:start position:0% +design process to help them develop +their own solutions to problems and work + + align:start position:0% +their own solutions to problems and work + + + align:start position:0% +their own solutions to problems and work +together with them and the nature of a + + align:start position:0% +together with them and the nature of a + + + align:start position:0% +together with them and the nature of a +dlab trip going for a week and spring + + align:start position:0% +dlab trip going for a week and spring + + + align:start position:0% +dlab trip going for a week and spring +break is we can't fully achieve all of + + align:start position:0% +break is we can't fully achieve all of + + + align:start position:0% +break is we can't fully achieve all of +this but at least if we have this in + + align:start position:0% +this but at least if we have this in + + + align:start position:0% +this but at least if we have this in +mind we can achieve as much of it as + + align:start position:0% +mind we can achieve as much of it as + + + align:start position:0% +mind we can achieve as much of it as +possible um some of the amazing things + + align:start position:0% +possible um some of the amazing things + + + align:start position:0% +possible um some of the amazing things +that happened on this trip is that um + + align:start position:0% +that happened on this trip is that um + + + align:start position:0% +that happened on this trip is that um +the translator they were working with + + align:start position:0% +the translator they were working with + + + align:start position:0% +the translator they were working with +told them that they they were the first + + align:start position:0% +told them that they they were the first + + + align:start position:0% +told them that they they were the first +um foreigners that this Camp had ever + + align:start position:0% +um foreigners that this Camp had ever + + + align:start position:0% +um foreigners that this Camp had ever +seen who actually did work because most + + align:start position:0% +seen who actually did work because most + + + align:start position:0% +seen who actually did work because most +people who come to do relief work come + + align:start position:0% +people who come to do relief work come + + + align:start position:0% +people who come to do relief work come +with clipboards and do a lot of + + align:start position:0% +with clipboards and do a lot of + + + align:start position:0% +with clipboards and do a lot of +interviews and ask a lot of questions um + + align:start position:0% +interviews and ask a lot of questions um + + + align:start position:0% +interviews and ask a lot of questions um +this is not to attack all relief work + + align:start position:0% +this is not to attack all relief work + + + align:start position:0% +this is not to attack all relief work +right there's a lot of groly work that + + align:start position:0% +right there's a lot of groly work that + + + align:start position:0% +right there's a lot of groly work that +goes on but there's also a lot of + + align:start position:0% +goes on but there's also a lot of + + + align:start position:0% +goes on but there's also a lot of +clipboard question asking and there's a + + align:start position:0% +clipboard question asking and there's a + + + align:start position:0% +clipboard question asking and there's a +need for that but um actually having + + align:start position:0% +need for that but um actually having + + + align:start position:0% +need for that but um actually having +people come and do work and work side by + + align:start position:0% +people come and do work and work side by + + + align:start position:0% +people come and do work and work side by +side is pretty + + align:start position:0% +side is pretty + + + align:start position:0% +side is pretty +valuable so for example here's Kofi + + align:start position:0% +valuable so for example here's Kofi + + + align:start position:0% +valuable so for example here's Kofi +chopping wood for making fires because + + align:start position:0% +chopping wood for making fires because + + + align:start position:0% +chopping wood for making fires because +that's what needed to be done so he + + align:start position:0% +that's what needed to be done so he + + + align:start position:0% +that's what needed to be done so he +helped out doing it and that's the kind + + align:start position:0% +helped out doing it and that's the kind + + + align:start position:0% +helped out doing it and that's the kind +of thing that you might start to do when + + align:start position:0% +of thing that you might start to do when + + + align:start position:0% +of thing that you might start to do when +you're in your community next week um + + align:start position:0% +you're in your community next week um + + + align:start position:0% +you're in your community next week um +however you don't see a picture of Amy + + align:start position:0% +however you don't see a picture of Amy + + + align:start position:0% +however you don't see a picture of Amy +chopping wood but you do see a picture + + align:start position:0% +chopping wood but you do see a picture + + + align:start position:0% +chopping wood but you do see a picture +of Amy helping sweep up after their + + align:start position:0% +of Amy helping sweep up after their + + + align:start position:0% +of Amy helping sweep up after their +demonstration um and why is that well + + align:start position:0% +demonstration um and why is that well + + + align:start position:0% +demonstration um and why is that well +it's totally culturally inappropriate + + align:start position:0% +it's totally culturally inappropriate + + + align:start position:0% +it's totally culturally inappropriate +for Amy to chop wood this would be + + align:start position:0% +for Amy to chop wood this would be + + + align:start position:0% +for Amy to chop wood this would be +inappropriate for Kofi to help sweep up + + align:start position:0% +inappropriate for Kofi to help sweep up + + + align:start position:0% +inappropriate for Kofi to help sweep up +and so while it's great to break down + + align:start position:0% +and so while it's great to break down + + + align:start position:0% +and so while it's great to break down +gender barriers at some level you also + + align:start position:0% +gender barriers at some level you also + + + align:start position:0% +gender barriers at some level you also +need to be respectful and so Amy will + + align:start position:0% +need to be respectful and so Amy will + + + align:start position:0% +need to be respectful and so Amy will +happily chop firewood when given the + + align:start position:0% +happily chop firewood when given the + + + align:start position:0% +happily chop firewood when given the +opportunity but if it's totally + + align:start position:0% +opportunity but if it's totally + + + align:start position:0% +opportunity but if it's totally +inappropriate she won't and vice versa + + align:start position:0% +inappropriate she won't and vice versa + + + align:start position:0% +inappropriate she won't and vice versa +so it's a balancing act about helping + + align:start position:0% +so it's a balancing act about helping + + + align:start position:0% +so it's a balancing act about helping +people um but also being respectful of + + align:start position:0% +people um but also being respectful of + + + align:start position:0% +people um but also being respectful of +what's appropriate so it can be very + + align:start position:0% +what's appropriate so it can be very + + + align:start position:0% +what's appropriate so it can be very +easy in communities to let people just + + align:start position:0% +easy in communities to let people just + + + align:start position:0% +easy in communities to let people just +help you people will be really kind and + + align:start position:0% +help you people will be really kind and + + + align:start position:0% +help you people will be really kind and +gracious and serve you and it's really + + align:start position:0% +gracious and serve you and it's really + + + align:start position:0% +gracious and serve you and it's really +important to make sure that you're + + align:start position:0% +important to make sure that you're + + + align:start position:0% +important to make sure that you're +acting as a community member working + + align:start position:0% +acting as a community member working + + + align:start position:0% +acting as a community member working +rather than someone who's a visitor or + + align:start position:0% +rather than someone who's a visitor or + + + align:start position:0% +rather than someone who's a visitor or +guest even though you are um only being + + align:start position:0% +guest even though you are um only being + + + align:start position:0% +guest even though you are um only being +helped + + align:start position:0% +helped + + + align:start position:0% +helped +um and the general rule of thumb is that + + align:start position:0% +um and the general rule of thumb is that + + + align:start position:0% +um and the general rule of thumb is that +Amy likes to say is people are people so + + align:start position:0% +Amy likes to say is people are people so + + + align:start position:0% +Amy likes to say is people are people so +if you you would help someone out here + + align:start position:0% +if you you would help someone out here + + + align:start position:0% +if you you would help someone out here +doing something you should do it there + + align:start position:0% +doing something you should do it there + + + align:start position:0% +doing something you should do it there +um and vice versa if you'd be really + + align:start position:0% +um and vice versa if you'd be really + + + align:start position:0% +um and vice versa if you'd be really +uncomfortable helping X here then you + + align:start position:0% +uncomfortable helping X here then you + + + align:start position:0% +uncomfortable helping X here then you +don't need to be force yourself to be + + align:start position:0% +don't need to be force yourself to be + + + align:start position:0% +don't need to be force yourself to be +super uncomfortable there um some of the + + align:start position:0% +super uncomfortable there um some of the + + + align:start position:0% +super uncomfortable there um some of the +advantages of doing this sort of + + align:start position:0% +advantages of doing this sort of + + + align:start position:0% +advantages of doing this sort of +participatory work are it's efficient + + align:start position:0% +participatory work are it's efficient + + + align:start position:0% +participatory work are it's efficient +and that's a sort of deceptive thing to + + align:start position:0% +and that's a sort of deceptive thing to + + + align:start position:0% +and that's a sort of deceptive thing to +say it's efficient because it takes a + + align:start position:0% +say it's efficient because it takes a + + + align:start position:0% +say it's efficient because it takes a +long time and can be really frustrating + + align:start position:0% +long time and can be really frustrating + + + align:start position:0% +long time and can be really frustrating +however if you're delivering a product + + align:start position:0% +however if you're delivering a product + + + align:start position:0% +however if you're delivering a product +that no one actually needs or is excited + + align:start position:0% +that no one actually needs or is excited + + + align:start position:0% +that no one actually needs or is excited +about then there's a real loss of + + align:start position:0% +about then there's a real loss of + + + align:start position:0% +about then there's a real loss of +efficiency there by not working with + + align:start position:0% +efficiency there by not working with + + + align:start position:0% +efficiency there by not working with +them in the first place um and similarly + + align:start position:0% +them in the first place um and similarly + + + align:start position:0% +them in the first place um and similarly +it can be effective to really work with + + align:start position:0% +it can be effective to really work with + + + align:start position:0% +it can be effective to really work with +people and get something that's really + + align:start position:0% +people and get something that's really + + + align:start position:0% +people and get something that's really +valuable um it can help transition + + align:start position:0% +valuable um it can help transition + + + align:start position:0% +valuable um it can help transition +people to a level of self-reliance they + + align:start position:0% +people to a level of self-reliance they + + + align:start position:0% +people to a level of self-reliance they +didn't have previously and help um your + + align:start position:0% +didn't have previously and help um your + + + align:start position:0% +didn't have previously and help um your +projects and the work become sustainable + + align:start position:0% +projects and the work become sustainable + + + align:start position:0% +projects and the work become sustainable +um some of the disadvantages are it's + + align:start position:0% +um some of the disadvantages are it's + + + align:start position:0% +um some of the disadvantages are it's +slow it takes a long time um it requires + + align:start position:0% +slow it takes a long time um it requires + + + align:start position:0% +slow it takes a long time um it requires +a lot of human and material resources + + align:start position:0% +a lot of human and material resources + + + align:start position:0% +a lot of human and material resources +potentially there's a lot of + + align:start position:0% +potentially there's a lot of + + + align:start position:0% +potentially there's a lot of +unpredictability as most teams have + + align:start position:0% +unpredictability as most teams have + + + align:start position:0% +unpredictability as most teams have +already experienced and if you haven't + + align:start position:0% +already experienced and if you haven't + + + align:start position:0% +already experienced and if you haven't +you will experience um and you have to + + align:start position:0% +you will experience um and you have to + + + align:start position:0% +you will experience um and you have to +be able to just roll with that + + align:start position:0% +be able to just roll with that + + + align:start position:0% +be able to just roll with that +unpredictability rather than getting + + align:start position:0% +unpredictability rather than getting + + + align:start position:0% +unpredictability rather than getting +super frustrated by it I mean you will + + align:start position:0% +super frustrated by it I mean you will + + + align:start position:0% +super frustrated by it I mean you will +get super frustrated by it but not + + align:start position:0% +get super frustrated by it but not + + + align:start position:0% +get super frustrated by it but not +letting that frustration be the dominant + + align:start position:0% +letting that frustration be the dominant + + + align:start position:0% +letting that frustration be the dominant +experience um and then finally ex + + align:start position:0% +experience um and then finally ex + + + align:start position:0% +experience um and then finally ex +managing expectations both of not um + + align:start position:0% +managing expectations both of not um + + + align:start position:0% +managing expectations both of not um +getting your Community Partners thinking + + align:start position:0% +getting your Community Partners thinking + + + align:start position:0% +getting your Community Partners thinking +that you're going to do something + + align:start position:0% +that you're going to do something + + + align:start position:0% +that you're going to do something +magical that isn't actually Within in + + align:start position:0% +magical that isn't actually Within in + + + align:start position:0% +magical that isn't actually Within in +your power or vice versa you yourself + + align:start position:0% +your power or vice versa you yourself + + + align:start position:0% +your power or vice versa you yourself +thinking you're going to be doing + + align:start position:0% +thinking you're going to be doing + + + align:start position:0% +thinking you're going to be doing +something amazing that's actually not + + align:start position:0% +something amazing that's actually not + + + align:start position:0% +something amazing that's actually not +reasonable to expect in the time and + + align:start position:0% +reasonable to expect in the time and + + + align:start position:0% +reasonable to expect in the time and +with the resources you + + align:start position:0% +with the resources you + + + align:start position:0% +with the resources you +have + + align:start position:0% + + + + align:start position:0% + +uh so the typical design process is + + align:start position:0% +uh so the typical design process is + + + align:start position:0% +uh so the typical design process is +you're trying to go from a problem to + + align:start position:0% +you're trying to go from a problem to + + + align:start position:0% +you're trying to go from a problem to +solution and you generally go through + + align:start position:0% +solution and you generally go through + + + align:start position:0% +solution and you generally go through +generating ideas evaluating them + + align:start position:0% +generating ideas evaluating them + + + align:start position:0% +generating ideas evaluating them +designing in more detail actually + + align:start position:0% +designing in more detail actually + + + align:start position:0% +designing in more detail actually +building testing and evaluation it's not + + align:start position:0% +building testing and evaluation it's not + + + align:start position:0% +building testing and evaluation it's not +actually the L linear of course but + + align:start position:0% +actually the L linear of course but + + + align:start position:0% +actually the L linear of course but +that's the general idea and so + + align:start position:0% +that's the general idea and so + + + align:start position:0% +that's the general idea and so +traditionally + + align:start position:0% + + + + align:start position:0% + +um you would involve communities just at + + align:start position:0% +um you would involve communities just at + + + align:start position:0% +um you would involve communities just at +the end um and that's obviously not + + align:start position:0% +the end um and that's obviously not + + + align:start position:0% +the end um and that's obviously not +ideal for all the reasons we've talked + + align:start position:0% +ideal for all the reasons we've talked + + + align:start position:0% +ideal for all the reasons we've talked +about and so then hopefully you involve + + align:start position:0% +about and so then hopefully you involve + + + align:start position:0% +about and so then hopefully you involve +them in the beginning and the idea of + + align:start position:0% +them in the beginning and the idea of + + + align:start position:0% +them in the beginning and the idea of +co-creation is that you're involving + + align:start position:0% +co-creation is that you're involving + + + align:start position:0% +co-creation is that you're involving +your community throughout all stages and + + align:start position:0% +your community throughout all stages and + + + align:start position:0% +your community throughout all stages and +so one thing to talk about when you are + + align:start position:0% +so one thing to talk about when you are + + + align:start position:0% +so one thing to talk about when you are +there is all right I'm not going to be + + align:start position:0% +there is all right I'm not going to be + + + align:start position:0% +there is all right I'm not going to be +here for the next few weeks while I'm + + align:start position:0% +here for the next few weeks while I'm + + + align:start position:0% +here for the next few weeks while I'm +doing all these steps how can I stay + + align:start position:0% +doing all these steps how can I stay + + + align:start position:0% +doing all these steps how can I stay +connected with you what's the best way + + align:start position:0% +connected with you what's the best way + + + align:start position:0% +connected with you what's the best way +way to be in contact with you um so that + + align:start position:0% +way to be in contact with you um so that + + + align:start position:0% +way to be in contact with you um so that +you can involve your Community Partners + + align:start position:0% +you can involve your Community Partners + + + align:start position:0% +you can involve your Community Partners +as much as + + align:start position:0% + + + + align:start position:0% + +possible there any questions about all + + align:start position:0% + + + + align:start position:0% + +that yeah you like with the like we have + + align:start position:0% +that yeah you like with the like we have + + + align:start position:0% +that yeah you like with the like we have +Lindsay do you mean with the people + + align:start position:0% +Lindsay do you mean with the people + + + align:start position:0% +Lindsay do you mean with the people +there like with so everyone so Lindsay + + align:start position:0% +there like with so everyone so Lindsay + + + align:start position:0% +there like with so everyone so Lindsay +is both really useful as a goet um but + + align:start position:0% +is both really useful as a goet um but + + + align:start position:0% +is both really useful as a goet um but +she also can't answer all the questions + + align:start position:0% +she also can't answer all the questions + + + align:start position:0% +she also can't answer all the questions +that you are going to have um because L + + align:start position:0% +that you are going to have um because L + + + align:start position:0% +that you are going to have um because L +Lindsay is one of the organizers of + + align:start position:0% +Lindsay is one of the organizers of + + + align:start position:0% +Lindsay is one of the organizers of +group of Phoenix um and so Lindsay may + + align:start position:0% +group of Phoenix um and so Lindsay may + + + align:start position:0% +group of Phoenix um and so Lindsay may +be the person you need to use to get the + + align:start position:0% +be the person you need to use to get the + + + align:start position:0% +be the person you need to use to get the +answers from the women you're working + + align:start position:0% +answers from the women you're working + + + align:start position:0% +answers from the women you're working +with but you can't just rely on Lindsay + + align:start position:0% +with but you can't just rely on Lindsay + + + align:start position:0% +with but you can't just rely on Lindsay +um reasonably but she may be the best + + align:start position:0% +um reasonably but she may be the best + + + align:start position:0% +um reasonably but she may be the best +way to get + + align:start position:0% +way to get + + + align:start position:0% +way to get +information so speaking of information + + align:start position:0% +information so speaking of information + + + align:start position:0% +information so speaking of information +um I want to talk a little bit about + + align:start position:0% +um I want to talk a little bit about + + + align:start position:0% +um I want to talk a little bit about +what the barriers are to getting in good + + align:start position:0% +what the barriers are to getting in good + + + align:start position:0% +what the barriers are to getting in good +information and some of the methods so + + align:start position:0% +information and some of the methods so + + + align:start position:0% +information and some of the methods so +what makes getting good information hard + + align:start position:0% +what makes getting good information hard + + + align:start position:0% +what makes getting good information hard +and what would you do to get good + + align:start position:0% +and what would you do to get good + + + align:start position:0% +and what would you do to get good +information and by information I mean + + align:start position:0% +information and by information I mean + + + align:start position:0% +information and by information I mean +learning you know is this uh solar + + align:start position:0% +learning you know is this uh solar + + + align:start position:0% +learning you know is this uh solar +cooker design actually a good idea uh + + align:start position:0% +cooker design actually a good idea uh + + + align:start position:0% +cooker design actually a good idea uh +how often do you cook with the solar + + align:start position:0% +how often do you cook with the solar + + + align:start position:0% +how often do you cook with the solar +cooker etc etc so + + align:start position:0% +cooker etc etc so + + + align:start position:0% +cooker etc etc so +yeah language language + + align:start position:0% + + + + align:start position:0% + +yeah what else + + align:start position:0% + + + + align:start position:0% + +whichever reiteration of ask the + + align:start position:0% +whichever reiteration of ask the + + + align:start position:0% +whichever reiteration of ask the +question multiple times to make sure you + + align:start position:0% +question multiple times to make sure you + + + align:start position:0% +question multiple times to make sure you +get + + align:start position:0% +get + + + align:start position:0% +get +answer another way that would be + + align:start position:0% +answer another way that would be + + + align:start position:0% +answer another way that would be +physical experience firstand experience + + align:start position:0% +physical experience firstand experience + + + align:start position:0% +physical experience firstand experience +not firstand but + + align:start position:0% +not firstand but + + + align:start position:0% +not firstand but +just well I think both actually + + align:start position:0% + + + + align:start position:0% + +what + + align:start position:0% +what + + + align:start position:0% +what +else cultural + + align:start position:0% + + + + align:start position:0% + +yep + + align:start position:0% +yep + + + align:start position:0% +yep +that teaming + + align:start position:0% + + + + align:start position:0% + +I think sometimes you might run into + + align:start position:0% +I think sometimes you might run into + + + align:start position:0% +I think sometimes you might run into +like some people think one thing but + + align:start position:0% +like some people think one thing but + + + align:start position:0% +like some people think one thing but +some people think another so having to + + align:start position:0% +some people think another so having to + + + align:start position:0% +some people think another so having to +like figure out get an over El + + align:start position:0% + + + + align:start position:0% + +just yeah + + align:start position:0% +just yeah + + + align:start position:0% +just yeah +absolutely I think time is an issue + + align:start position:0% +absolutely I think time is an issue + + + align:start position:0% +absolutely I think time is an issue +since what we did for one week and we're + + align:start position:0% +since what we did for one week and we're + + + align:start position:0% +since what we did for one week and we're +all very ambitious we want to get the + + align:start position:0% +all very ambitious we want to get the + + + align:start position:0% +all very ambitious we want to get the +most out of it + + align:start position:0% +most out of it + + + align:start position:0% +most out of it +and maybe like we'll want to like kind + + align:start position:0% +and maybe like we'll want to like kind + + + align:start position:0% +and maybe like we'll want to like kind +of bypass small little things into them + + align:start position:0% +of bypass small little things into them + + + align:start position:0% +of bypass small little things into them +may make a big difference like + + align:start position:0% +may make a big difference like + + + align:start position:0% +may make a big difference like +introducing ourselves and making that + + align:start position:0% +introducing ourselves and making that + + + align:start position:0% +introducing ourselves and making that +establishing the personal contact that + + align:start position:0% +establishing the personal contact that + + + align:start position:0% +establishing the personal contact that +this guy didn't have yeah yeah you can + + align:start position:0% +this guy didn't have yeah yeah you can + + + align:start position:0% +this guy didn't have yeah yeah you can +get much better information from people + + align:start position:0% +get much better information from people + + + align:start position:0% +get much better information from people +if you actually spend the time to do the + + align:start position:0% +if you actually spend the time to do the + + + align:start position:0% +if you actually spend the time to do the +introductions and thankfully for you + + align:start position:0% +introductions and thankfully for you + + + align:start position:0% +introductions and thankfully for you +guys you're not in a community where + + align:start position:0% +guys you're not in a community where + + + align:start position:0% +guys you're not in a community where +it's traditional to spend like an hour + + align:start position:0% +it's traditional to spend like an hour + + + align:start position:0% +it's traditional to spend like an hour +doing the introd introductions and how + + align:start position:0% +doing the introd introductions and how + + + align:start position:0% +doing the introd introductions and how +is your family and this and that in + + align:start position:0% +is your family and this and that in + + + align:start position:0% +is your family and this and that in +Nicaragua at least in these areas is + + align:start position:0% +Nicaragua at least in these areas is + + + align:start position:0% +Nicaragua at least in these areas is +people are used to doing things a little + + align:start position:0% +people are used to doing things a little + + + align:start position:0% +people are used to doing things a little +more quickly but doing the Steve Ray + + align:start position:0% +more quickly but doing the Steve Ray + + + align:start position:0% +more quickly but doing the Steve Ray +approach not his approach but what he + + align:start position:0% +approach not his approach but what he + + + align:start position:0% +approach not his approach but what he +did of barging right in and being like + + align:start position:0% +did of barging right in and being like + + + align:start position:0% +did of barging right in and being like +oh let me see your shoelaces is probably + + align:start position:0% +oh let me see your shoelaces is probably + + + align:start position:0% +oh let me see your shoelaces is probably +not the best um spending the time to + + align:start position:0% +not the best um spending the time to + + + align:start position:0% +not the best um spending the time to +introduce yourself and get to know + + align:start position:0% +introduce yourself and get to know + + + align:start position:0% +introduce yourself and get to know +people a little bit it's definitely + + align:start position:0% +people a little bit it's definitely + + + align:start position:0% +people a little bit it's definitely +going to + + align:start position:0% + + + + align:start position:0% + +help okay + + align:start position:0% +help okay + + + align:start position:0% +help okay +so gender + + align:start position:0% + + + + align:start position:0% + +yep n doesn't have very much of like men + + align:start position:0% +yep n doesn't have very much of like men + + + align:start position:0% +yep n doesn't have very much of like men +over women kind of + + align:start position:0% +over women kind of + + + align:start position:0% +over women kind of +it depends who you talk to um but I + + align:start position:0% +it depends who you talk to um but I + + + align:start position:0% +it depends who you talk to um but I +would say it's not as Extreme as other + + align:start position:0% +would say it's not as Extreme as other + + + align:start position:0% +would say it's not as Extreme as other +places age going be a problem like are + + align:start position:0% +places age going be a problem like are + + + align:start position:0% +places age going be a problem like are +they going to have trouble respect + + align:start position:0% +they going to have trouble respect + + + align:start position:0% +they going to have trouble respect +people that are younger than them um I + + align:start position:0% +people that are younger than them um I + + + align:start position:0% +people that are younger than them um I +don't know it could be I didn't + + align:start position:0% +don't know it could be I didn't + + + align:start position:0% +don't know it could be I didn't +encounter it as a big issue but it's + + align:start position:0% +encounter it as a big issue but it's + + + align:start position:0% +encounter it as a big issue but it's +it's always a + + align:start position:0% + + + + align:start position:0% + +possibility so some of the issues I have + + align:start position:0% +possibility so some of the issues I have + + + align:start position:0% +possibility so some of the issues I have +encountered myself are so yes the + + align:start position:0% +encountered myself are so yes the + + + align:start position:0% +encountered myself are so yes the +language and some sometimes you deal + + align:start position:0% +language and some sometimes you deal + + + align:start position:0% +language and some sometimes you deal +with that with the translator whether + + align:start position:0% +with that with the translator whether + + + align:start position:0% +with that with the translator whether +it's someone on your team or someone on + + align:start position:0% +it's someone on your team or someone on + + + align:start position:0% +it's someone on your team or someone on +your in your community organization is + + align:start position:0% +your in your community organization is + + + align:start position:0% +your in your community organization is +helping um educational backgrounds are + + align:start position:0% +helping um educational backgrounds are + + + align:start position:0% +helping um educational backgrounds are +different cultural backgrounds are + + align:start position:0% +different cultural backgrounds are + + + align:start position:0% +different cultural backgrounds are +different people tell you what you want + + align:start position:0% +different people tell you what you want + + + align:start position:0% +different people tell you what you want +to hear what they think you want to hear + + align:start position:0% +to hear what they think you want to hear + + + align:start position:0% +to hear what they think you want to hear +as opposed to what you actually want to + + align:start position:0% +as opposed to what you actually want to + + + align:start position:0% +as opposed to what you actually want to +hear um and you may be easily talking to + + align:start position:0% +hear um and you may be easily talking to + + + align:start position:0% +hear um and you may be easily talking to +the wrong person so to get into those a + + align:start position:0% +the wrong person so to get into those a + + + align:start position:0% +the wrong person so to get into those a +little more so language obviously um is + + align:start position:0% +little more so language obviously um is + + + align:start position:0% +little more so language obviously um is +challenging and when you use a + + align:start position:0% +challenging and when you use a + + + align:start position:0% +challenging and when you use a +translator there's often times where you + + align:start position:0% +translator there's often times where you + + + align:start position:0% +translator there's often times where you +ask a question that you know Tak you 2 + + align:start position:0% +ask a question that you know Tak you 2 + + + align:start position:0% +ask a question that you know Tak you 2 +minutes to say and the translator asks a + + align:start position:0% +minutes to say and the translator asks a + + + align:start position:0% +minutes to say and the translator asks a +1 second question and then the person + + align:start position:0% +1 second question and then the person + + + align:start position:0% +1 second question and then the person +responds by talking for three minutes + + align:start position:0% +responds by talking for three minutes + + + align:start position:0% +responds by talking for three minutes +and the translator says + + align:start position:0% +and the translator says + + + align:start position:0% +and the translator says +yes um and that can be really + + align:start position:0% +yes um and that can be really + + + align:start position:0% +yes um and that can be really +frustrating and at the same time you're + + align:start position:0% +frustrating and at the same time you're + + + align:start position:0% +frustrating and at the same time you're +completely beholden to your translator + + align:start position:0% +completely beholden to your translator + + + align:start position:0% +completely beholden to your translator +so if you take them outside and yell at + + align:start position:0% +so if you take them outside and yell at + + + align:start position:0% +so if you take them outside and yell at +them I mean I don't think that's going + + align:start position:0% +them I mean I don't think that's going + + + align:start position:0% +them I mean I don't think that's going +to happen right but if that you know if + + align:start position:0% +to happen right but if that you know if + + + align:start position:0% +to happen right but if that you know if +you took a really pissed-off approach to + + align:start position:0% +you took a really pissed-off approach to + + + align:start position:0% +you took a really pissed-off approach to +this the effect would be um even worse + + align:start position:0% +this the effect would be um even worse + + + align:start position:0% +this the effect would be um even worse +response from your translation + + align:start position:0% +response from your translation + + + align:start position:0% +response from your translation +um educational backgrounds so what I + + align:start position:0% +um educational backgrounds so what I + + + align:start position:0% +um educational backgrounds so what I +mean by that is that most of us are + + align:start position:0% +mean by that is that most of us are + + + align:start position:0% +mean by that is that most of us are +pretty used to talking in watts in + + align:start position:0% +pretty used to talking in watts in + + + align:start position:0% +pretty used to talking in watts in +jewels in inches whatever in units and + + align:start position:0% +jewels in inches whatever in units and + + + align:start position:0% +jewels in inches whatever in units and +just with a math sense and if you + + align:start position:0% +just with a math sense and if you + + + align:start position:0% +just with a math sense and if you +haven't had a math education you may + + align:start position:0% +haven't had a math education you may + + + align:start position:0% +haven't had a math education you may +have a really intuitive understanding of + + align:start position:0% +have a really intuitive understanding of + + + align:start position:0% +have a really intuitive understanding of +all those Concepts but you don't + + align:start position:0% +all those Concepts but you don't + + + align:start position:0% +all those Concepts but you don't +actually have the language the same + + align:start position:0% +actually have the language the same + + + align:start position:0% +actually have the language the same +language um so it's not a Spanish versus + + align:start position:0% +language um so it's not a Spanish versus + + + align:start position:0% +language um so it's not a Spanish versus +English barrier it's a educational + + align:start position:0% +English barrier it's a educational + + + align:start position:0% +English barrier it's a educational +language barrier and so you are it's + + align:start position:0% +language barrier and so you are it's + + + align:start position:0% +language barrier and so you are it's +beholden on you when some you say well + + align:start position:0% +beholden on you when some you say well + + + align:start position:0% +beholden on you when some you say well +how long long is that expecting 3 in and + + align:start position:0% +how long long is that expecting 3 in and + + + align:start position:0% +how long long is that expecting 3 in and +someone you know answers like you know + + align:start position:0% +someone you know answers like you know + + + align:start position:0% +someone you know answers like you know +some other analogy figuring out how to + + align:start position:0% +some other analogy figuring out how to + + + align:start position:0% +some other analogy figuring out how to +translate that rather than saying well + + align:start position:0% +translate that rather than saying well + + + align:start position:0% +translate that rather than saying well +is that 6 in or 8 in right because + + align:start position:0% +is that 6 in or 8 in right because + + + align:start position:0% +is that 6 in or 8 in right because +that's not going to give you very useful + + align:start position:0% +that's not going to give you very useful + + + align:start position:0% +that's not going to give you very useful +information and they do + + align:start position:0% +information and they do + + + align:start position:0% +information and they do +cim I saw both really + + align:start position:0% +cim I saw both really + + + align:start position:0% +cim I saw both really +yeah um but a lot of it is without + + align:start position:0% +yeah um but a lot of it is without + + + align:start position:0% +yeah um but a lot of it is without +standard units too like a lot of people + + align:start position:0% +standard units too like a lot of people + + + align:start position:0% +standard units too like a lot of people +just aren't used to units and units of + + align:start position:0% +just aren't used to units and units of + + + align:start position:0% +just aren't used to units and units of +measure like um what you're used to um + + align:start position:0% +measure like um what you're used to um + + + align:start position:0% +measure like um what you're used to um +cultural background of course um and + + align:start position:0% +cultural background of course um and + + + align:start position:0% +cultural background of course um and +then telling you what you want to hear + + align:start position:0% +then telling you what you want to hear + + + align:start position:0% +then telling you what you want to hear +it's really common if you say so what do + + align:start position:0% +it's really common if you say so what do + + + align:start position:0% +it's really common if you say so what do +you think of my design right people be + + align:start position:0% +you think of my design right people be + + + align:start position:0% +you think of my design right people be +like oh it's great yeah we totally use + + align:start position:0% +like oh it's great yeah we totally use + + + align:start position:0% +like oh it's great yeah we totally use +that awesome love it yeah it's good mhm + + align:start position:0% +that awesome love it yeah it's good mhm + + + align:start position:0% +that awesome love it yeah it's good mhm +and unless you both ask your question + + align:start position:0% +and unless you both ask your question + + + align:start position:0% +and unless you both ask your question +more carefully and keep probing you'll + + align:start position:0% +more carefully and keep probing you'll + + + align:start position:0% +more carefully and keep probing you'll +never hear beyond that and it's really + + align:start position:0% +never hear beyond that and it's really + + + align:start position:0% +never hear beyond that and it's really +easy when you're proud of something to + + align:start position:0% +easy when you're proud of something to + + + align:start position:0% +easy when you're proud of something to +be like well they said do they love it + + align:start position:0% +be like well they said do they love it + + + align:start position:0% +be like well they said do they love it +awesome and so working through that is + + align:start position:0% +awesome and so working through that is + + + align:start position:0% +awesome and so working through that is +is important and then also talking to + + align:start position:0% +is important and then also talking to + + + align:start position:0% +is important and then also talking to +the wrong person so it can be really + + align:start position:0% +the wrong person so it can be really + + + align:start position:0% +the wrong person so it can be really +easy to ask all questions of Lindsay for + + align:start position:0% +easy to ask all questions of Lindsay for + + + align:start position:0% +easy to ask all questions of Lindsay for +example is the community or organizer + + align:start position:0% +example is the community or organizer + + + align:start position:0% +example is the community or organizer +and she speaks English Etc and she'll + + align:start position:0% +and she speaks English Etc and she'll + + + align:start position:0% +and she speaks English Etc and she'll +give you some really good insights but + + align:start position:0% +give you some really good insights but + + + align:start position:0% +give you some really good insights but +if you just talk to her you won't get + + align:start position:0% +if you just talk to her you won't get + + + align:start position:0% +if you just talk to her you won't get +the right information or you can + + align:start position:0% +the right information or you can + + + align:start position:0% +the right information or you can +interview someone about cooking habits + + align:start position:0% +interview someone about cooking habits + + + align:start position:0% +interview someone about cooking habits +and then if you forget to ask how often + + align:start position:0% +and then if you forget to ask how often + + + align:start position:0% +and then if you forget to ask how often +do you cook and find out actually they + + align:start position:0% +do you cook and find out actually they + + + align:start position:0% +do you cook and find out actually they +aren't the cook but they'll answer + + align:start position:0% +aren't the cook but they'll answer + + + align:start position:0% +aren't the cook but they'll answer +because you're asking these questions if + + align:start position:0% +because you're asking these questions if + + + align:start position:0% +because you're asking these questions if +you don't ask the right questions you're + + align:start position:0% +you don't ask the right questions you're + + + align:start position:0% +you don't ask the right questions you're +just never going to get the right + + align:start position:0% +just never going to get the right + + + align:start position:0% +just never going to get the right +information and there's classic examples + + align:start position:0% +information and there's classic examples + + + align:start position:0% +information and there's classic examples +of that in terms of talking to the male + + align:start position:0% +of that in terms of talking to the male + + + align:start position:0% +of that in terms of talking to the male +leaders in the community and never + + align:start position:0% +leaders in the community and never + + + align:start position:0% +leaders in the community and never +talking to the women in the community I + + align:start position:0% +talking to the women in the community I + + + align:start position:0% +talking to the women in the community I +think that'll be less of an issue for + + align:start position:0% +think that'll be less of an issue for + + + align:start position:0% +think that'll be less of an issue for +most of you guys given who you're + + align:start position:0% +most of you guys given who you're + + + align:start position:0% +most of you guys given who you're +working with but it's something to keep + + align:start position:0% +working with but it's something to keep + + + align:start position:0% +working with but it's something to keep +in + + align:start position:0% +in + + + align:start position:0% +in +mind so I sort of got to this and you + + align:start position:0% +mind so I sort of got to this and you + + + align:start position:0% +mind so I sort of got to this and you +got to it too so one some of the methods + + align:start position:0% +got to it too so one some of the methods + + + align:start position:0% +got to it too so one some of the methods +to manage this are asking the same + + align:start position:0% +to manage this are asking the same + + + align:start position:0% +to manage this are asking the same +person the same question in many + + align:start position:0% +person the same question in many + + + align:start position:0% +person the same question in many +different ways multiple times as well as + + align:start position:0% +different ways multiple times as well as + + + align:start position:0% +different ways multiple times as well as +asking different people the same + + align:start position:0% +asking different people the same + + + align:start position:0% +asking different people the same +question multiple times anticipating + + align:start position:0% +question multiple times anticipating + + + align:start position:0% +question multiple times anticipating +that you're going to get some variation + + align:start position:0% +that you're going to get some variation + + + align:start position:0% +that you're going to get some variation +another thing you can do is ask some + + align:start position:0% +another thing you can do is ask some + + + align:start position:0% +another thing you can do is ask some +questions that you kind of already know + + align:start position:0% +questions that you kind of already know + + + align:start position:0% +questions that you kind of already know +the answer to um if if you do so that + + align:start position:0% +the answer to um if if you do so that + + + align:start position:0% +the answer to um if if you do so that +you can get an indicator of how reliable + + align:start position:0% +you can get an indicator of how reliable + + + align:start position:0% +you can get an indicator of how reliable +this person is in terms of giving you + + align:start position:0% +this person is in terms of giving you + + + align:start position:0% +this person is in terms of giving you +useful information because some people + + align:start position:0% +useful information because some people + + + align:start position:0% +useful information because some people +are much more on the telling you what + + align:start position:0% +are much more on the telling you what + + + align:start position:0% +are much more on the telling you what +you want way they think you want to hear + + align:start position:0% +you want way they think you want to hear + + + align:start position:0% +you want way they think you want to hear +sigh than others and there's some Pro + + align:start position:0% +sigh than others and there's some Pro + + + align:start position:0% +sigh than others and there's some Pro +probing questions you might be able to + + align:start position:0% +probing questions you might be able to + + + align:start position:0% +probing questions you might be able to +develop that um can help you get around + + align:start position:0% +develop that um can help you get around + + + align:start position:0% +develop that um can help you get around +that um demonstrating an openness to + + align:start position:0% +that um demonstrating an openness to + + + align:start position:0% +that um demonstrating an openness to +criticism and that generally does not + + align:start position:0% +criticism and that generally does not + + + align:start position:0% +criticism and that generally does not +mean saying oh you won't offend me tell + + align:start position:0% +mean saying oh you won't offend me tell + + + align:start position:0% +mean saying oh you won't offend me tell +me whatever you want but can mean + + align:start position:0% +me whatever you want but can mean + + + align:start position:0% +me whatever you want but can mean +something like you know I've talked to + + align:start position:0% +something like you know I've talked to + + + align:start position:0% +something like you know I've talked to +some people who've criticized or you + + align:start position:0% +some people who've criticized or you + + + align:start position:0% +some people who've criticized or you +know have said they don't like this idea + + align:start position:0% +know have said they don't like this idea + + + align:start position:0% +know have said they don't like this idea +because of this you know is that + + align:start position:0% +because of this you know is that + + + align:start position:0% +because of this you know is that +something that you you think might be a + + align:start position:0% +something that you you think might be a + + + align:start position:0% +something that you you think might be a +problem too why or why not um and just + + align:start position:0% +problem too why or why not um and just + + + align:start position:0% +problem too why or why not um and just +repeatedly attacking yourself so that + + align:start position:0% +repeatedly attacking yourself so that + + + align:start position:0% +repeatedly attacking yourself so that +that you actually get some criticisms + + align:start position:0% +that you actually get some criticisms + + + align:start position:0% +that you actually get some criticisms +from them because as great as you all + + align:start position:0% +from them because as great as you all + + + align:start position:0% +from them because as great as you all +are I'm sure there's going to be some + + align:start position:0% +are I'm sure there's going to be some + + + align:start position:0% +are I'm sure there's going to be some +flaws in every approach and so getting + + align:start position:0% +flaws in every approach and so getting + + + align:start position:0% +flaws in every approach and so getting +to those flaws helps you get to a really + + align:start position:0% +to those flaws helps you get to a really + + + align:start position:0% +to those flaws helps you get to a really +great product faster um repeating + + align:start position:0% +great product faster um repeating + + + align:start position:0% +great product faster um repeating +answers back is sort of a classic method + + align:start position:0% +answers back is sort of a classic method + + + align:start position:0% +answers back is sort of a classic method +for making sure that there's + + align:start position:0% +for making sure that there's + + + align:start position:0% +for making sure that there's +understanding on both sides encouraging + + align:start position:0% +understanding on both sides encouraging + + + align:start position:0% +understanding on both sides encouraging +questions very explicitly saying you + + align:start position:0% +questions very explicitly saying you + + + align:start position:0% +questions very explicitly saying you +know what questions do you have for me + + align:start position:0% +know what questions do you have for me + + + align:start position:0% +know what questions do you have for me +what can I tell you um is pretty + + align:start position:0% +what can I tell you um is pretty + + + align:start position:0% +what can I tell you um is pretty +important uh verifying expertise so sort + + align:start position:0% +important uh verifying expertise so sort + + + align:start position:0% +important uh verifying expertise so sort +of as I mentioned with the wrong person + + align:start position:0% +of as I mentioned with the wrong person + + + align:start position:0% +of as I mentioned with the wrong person +if you talk to someone about cooking + + align:start position:0% +if you talk to someone about cooking + + + align:start position:0% +if you talk to someone about cooking +actually making sure that they cook + + align:start position:0% +actually making sure that they cook + + + align:start position:0% +actually making sure that they cook +would be a good good thing to do um and + + align:start position:0% +would be a good good thing to do um and + + + align:start position:0% +would be a good good thing to do um and +then finally dealing with the translator + + align:start position:0% +then finally dealing with the translator + + + align:start position:0% +then finally dealing with the translator +spending some time beforehand talking + + align:start position:0% +spending some time beforehand talking + + + align:start position:0% +spending some time beforehand talking +about what your goals are what your + + align:start position:0% +about what your goals are what your + + + align:start position:0% +about what your goals are what your +preferences are um because translators + + align:start position:0% +preferences are um because translators + + + align:start position:0% +preferences are um because translators +have choices in terms of do they give + + align:start position:0% +have choices in terms of do they give + + + align:start position:0% +have choices in terms of do they give +you the detailed response or do they + + align:start position:0% +you the detailed response or do they + + + align:start position:0% +you the detailed response or do they +just give you the yes and if you're on a + + align:start position:0% +just give you the yes and if you're on a + + + align:start position:0% +just give you the yes and if you're on a +time crunch you may just want the yes + + align:start position:0% +time crunch you may just want the yes + + + align:start position:0% +time crunch you may just want the yes +but if you have the time you probably + + align:start position:0% +but if you have the time you probably + + + align:start position:0% +but if you have the time you probably +want the detailed um answer with the + + align:start position:0% +want the detailed um answer with the + + + align:start position:0% +want the detailed um answer with the +subtleties even if it's more painful to + + align:start position:0% + + + + align:start position:0% + +translate so one of the challenges is + + align:start position:0% +translate so one of the challenges is + + + align:start position:0% +translate so one of the challenges is +when you're working on engineering + + align:start position:0% +when you're working on engineering + + + align:start position:0% +when you're working on engineering +projects is getting to the core problem + + align:start position:0% +projects is getting to the core problem + + + align:start position:0% +projects is getting to the core problem +um and that sort of ties in to the + + align:start position:0% +um and that sort of ties in to the + + + align:start position:0% +um and that sort of ties in to the +project spec specifications so someone + + align:start position:0% +project spec specifications so someone + + + align:start position:0% +project spec specifications so someone +will say I need a new stove instead of I + + align:start position:0% +will say I need a new stove instead of I + + + align:start position:0% +will say I need a new stove instead of I +need to not have such a smoky + + align:start position:0% +need to not have such a smoky + + + align:start position:0% +need to not have such a smoky +environment in my kitchen and you need + + align:start position:0% +environment in my kitchen and you need + + + align:start position:0% +environment in my kitchen and you need +to make sure you're asking the questions + + align:start position:0% +to make sure you're asking the questions + + + align:start position:0% +to make sure you're asking the questions +to get to smoking environment not new + + align:start position:0% +to get to smoking environment not new + + + align:start position:0% +to get to smoking environment not new +stove right and be really easy to + + align:start position:0% +stove right and be really easy to + + + align:start position:0% +stove right and be really easy to +specify that brand new stove without um + + align:start position:0% +specify that brand new stove without um + + + align:start position:0% +specify that brand new stove without um +getting uh the right and question + + align:start position:0% +getting uh the right and question + + + align:start position:0% +getting uh the right and question +answered which is the smoking + + align:start position:0% +answered which is the smoking + + + align:start position:0% +answered which is the smoking +environment so partly it's making sure + + align:start position:0% +environment so partly it's making sure + + + align:start position:0% +environment so partly it's making sure +that you're not letting them design for + + align:start position:0% +that you're not letting them design for + + + align:start position:0% +that you're not letting them design for +you which everyone does it's really hard + + align:start position:0% +you which everyone does it's really hard + + + align:start position:0% +you which everyone does it's really hard +to describe what you need in terms of + + align:start position:0% +to describe what you need in terms of + + + align:start position:0% +to describe what you need in terms of +specifications as you probably just + + align:start position:0% +specifications as you probably just + + + align:start position:0% +specifications as you probably just +found out um or saw in that 29 lecture I + + align:start position:0% +found out um or saw in that 29 lecture I + + + align:start position:0% +found out um or saw in that 29 lecture I +linked to when trying to describe a + + align:start position:0% +linked to when trying to describe a + + + align:start position:0% +linked to when trying to describe a +lemon or a piece of fruit um um as a + + align:start position:0% +lemon or a piece of fruit um um as a + + + align:start position:0% +lemon or a piece of fruit um um as a +project specification rather than I need + + align:start position:0% +project specification rather than I need + + + align:start position:0% +project specification rather than I need +a lemon right um that's much harder but + + align:start position:0% +a lemon right um that's much harder but + + + align:start position:0% +a lemon right um that's much harder but +that's what you this is actually the + + align:start position:0% +that's what you this is actually the + + + align:start position:0% +that's what you this is actually the +information you need to make a good + + align:start position:0% +information you need to make a good + + + align:start position:0% +information you need to make a good +design so that you're not going down the + + align:start position:0% +design so that you're not going down the + + + align:start position:0% +design so that you're not going down the +path of a design that may not actually + + align:start position:0% +path of a design that may not actually + + + align:start position:0% +path of a design that may not actually +match the real needs um because it's + + align:start position:0% +match the real needs um because it's + + + align:start position:0% +match the real needs um because it's +easier to think in products than in + + align:start position:0% + + + + align:start position:0% + +specifications uh so getting to the core + + align:start position:0% +specifications uh so getting to the core + + + align:start position:0% +specifications uh so getting to the core +problem some ways you can do that in + + align:start position:0% +problem some ways you can do that in + + + align:start position:0% +problem some ways you can do that in +addition to just being patient when + + align:start position:0% +addition to just being patient when + + + align:start position:0% +addition to just being patient when +people talk about what they want in + + align:start position:0% +people talk about what they want in + + + align:start position:0% +people talk about what they want in +terms of a product and then you + + align:start position:0% +terms of a product and then you + + + align:start position:0% +terms of a product and then you +translating back into the specifications + + align:start position:0% +translating back into the specifications + + + align:start position:0% +translating back into the specifications +is so tell me what would happen when you + + align:start position:0% +is so tell me what would happen when you + + + align:start position:0% +is so tell me what would happen when you +use this new thing tell me a story about + + align:start position:0% +use this new thing tell me a story about + + + align:start position:0% +use this new thing tell me a story about +what that would be like and have them + + align:start position:0% +what that would be like and have them + + + align:start position:0% +what that would be like and have them +sort of walk you through what life is + + align:start position:0% +sort of walk you through what life is + + + align:start position:0% +sort of walk you through what life is +like with this new Option um talk you + + align:start position:0% +like with this new Option um talk you + + + align:start position:0% +like with this new Option um talk you +know when you're trying to find out more + + align:start position:0% +know when you're trying to find out more + + + align:start position:0% +know when you're trying to find out more +about what those specifications are + + align:start position:0% +about what those specifications are + + + align:start position:0% +about what those specifications are +rather than saying how big should it be + + align:start position:0% +rather than saying how big should it be + + + align:start position:0% +rather than saying how big should it be +saying well how big is too big is 10et + + align:start position:0% +saying well how big is too big is 10et + + + align:start position:0% +saying well how big is too big is 10et +you know is is this big too big is this + + align:start position:0% +you know is is this big too big is this + + + align:start position:0% +you know is is this big too big is this +big too big and again I just said 10 ft + + align:start position:0% +big too big and again I just said 10 ft + + + align:start position:0% +big too big and again I just said 10 ft +and that's probably not what you want to + + align:start position:0% +and that's probably not what you want to + + + align:start position:0% +and that's probably not what you want to +say you want to use your hands to + + align:start position:0% +say you want to use your hands to + + + align:start position:0% +say you want to use your hands to +gesture or use some other things to + + align:start position:0% +gesture or use some other things to + + + align:start position:0% +gesture or use some other things to +compare because 10 ft even for us is a + + align:start position:0% +compare because 10 ft even for us is a + + + align:start position:0% +compare because 10 ft even for us is a +little hard to imagine exactly how big + + align:start position:0% +little hard to imagine exactly how big + + + align:start position:0% +little hard to imagine exactly how big +10t is and for someone who hasn't grown + + align:start position:0% +10t is and for someone who hasn't grown + + + align:start position:0% +10t is and for someone who hasn't grown +up using um rulers and tape measures Etc + + align:start position:0% +up using um rulers and tape measures Etc + + + align:start position:0% +up using um rulers and tape measures Etc +it's harder um and so I put big and + + align:start position:0% +it's harder um and so I put big and + + + align:start position:0% +it's harder um and so I put big and +small in parenthesis because it could be + + align:start position:0% +small in parenthesis because it could be + + + align:start position:0% +small in parenthesis because it could be +like how hot how cold how whatever all + + align:start position:0% +like how hot how cold how whatever all + + + align:start position:0% +like how hot how cold how whatever all +sorts of different things um challenge + + align:start position:0% +sorts of different things um challenge + + + align:start position:0% +sorts of different things um challenge +challenge their requests so like if they + + align:start position:0% +challenge their requests so like if they + + + align:start position:0% +challenge their requests so like if they +say oh no it has to be you know it can't + + align:start position:0% +say oh no it has to be you know it can't + + + align:start position:0% +say oh no it has to be you know it can't +be bigger than this say well what would + + align:start position:0% +be bigger than this say well what would + + + align:start position:0% +be bigger than this say well what would +happen if it was this big why would that + + align:start position:0% +happen if it was this big why would that + + + align:start position:0% +happen if it was this big why would that +be a bad thing so that you really + + align:start position:0% +be a bad thing so that you really + + + align:start position:0% +be a bad thing so that you really +understand what they're getting at um + + align:start position:0% +understand what they're getting at um + + + align:start position:0% +understand what they're getting at um +and then get getting feedback on your + + align:start position:0% +and then get getting feedback on your + + + align:start position:0% +and then get getting feedback on your +own ideas including ones that you know + + align:start position:0% +own ideas including ones that you know + + + align:start position:0% +own ideas including ones that you know +are problematic so showing them a design + + align:start position:0% +are problematic so showing them a design + + + align:start position:0% +are problematic so showing them a design +that you know has some issues and + + align:start position:0% +that you know has some issues and + + + align:start position:0% +that you know has some issues and +getting feedback on it trying to get + + align:start position:0% +getting feedback on it trying to get + + + align:start position:0% +getting feedback on it trying to get +them comfortable with criticizing um so + + align:start position:0% +them comfortable with criticizing um so + + + align:start position:0% +them comfortable with criticizing um so +that you can and then also listening to + + align:start position:0% +that you can and then also listening to + + + align:start position:0% +that you can and then also listening to +the way they're criticizing what they're + + align:start position:0% +the way they're criticizing what they're + + + align:start position:0% +the way they're criticizing what they're +C catching maybe open up some + + align:start position:0% +C catching maybe open up some + + + align:start position:0% +C catching maybe open up some +information for you um and then finally + + align:start position:0% +information for you um and then finally + + + align:start position:0% +information for you um and then finally +as you're engaged in these questions and + + align:start position:0% +as you're engaged in these questions and + + + align:start position:0% +as you're engaged in these questions and +conversations taking time mentally um to + + align:start position:0% +conversations taking time mentally um to + + + align:start position:0% +conversations taking time mentally um to +view what you know and sort of do a + + align:start position:0% +view what you know and sort of do a + + + align:start position:0% +view what you know and sort of do a +mental design process of writing down + + align:start position:0% +mental design process of writing down + + + align:start position:0% +mental design process of writing down +the specifications and being like okay I + + align:start position:0% +the specifications and being like okay I + + + align:start position:0% +the specifications and being like okay I +know these things what else don't I know + + align:start position:0% +know these things what else don't I know + + + align:start position:0% +know these things what else don't I know +so that you make sure to get to all the + + align:start position:0% +so that you make sure to get to all the + + + align:start position:0% +so that you make sure to get to all the +questions you need to ask and it's kind + + align:start position:0% +questions you need to ask and it's kind + + + align:start position:0% +questions you need to ask and it's kind +of hard and takes practice but you guys + + align:start position:0% +of hard and takes practice but you guys + + + align:start position:0% +of hard and takes practice but you guys +will uh do + + align:start position:0% +will uh do + + + align:start position:0% +will uh do +great so now + + align:start position:0% +great so now + + + align:start position:0% +great so now +um I'm G to save that till Friday + + align:start position:0% +um I'm G to save that till Friday + + + align:start position:0% +um I'm G to save that till Friday +because we're running out of + + align:start position:0% +because we're running out of + + + align:start position:0% +because we're running out of +time + + align:start position:0% +time + + + align:start position:0% +time +um so I just wanted to go over or maybe + + align:start position:0% +um so I just wanted to go over or maybe + + + align:start position:0% +um so I just wanted to go over or maybe +I'll get back to it if I have time um + + align:start position:0% +I'll get back to it if I have time um + + + align:start position:0% +I'll get back to it if I have time um +the packing list and trip uh advice + + align:start position:0% +the packing list and trip uh advice + + + align:start position:0% +the packing list and trip uh advice +which is all posted on Stellar but in + + align:start position:0% +which is all posted on Stellar but in + + + align:start position:0% +which is all posted on Stellar but in +case you haven't had a chance to read it + + align:start position:0% +case you haven't had a chance to read it + + + align:start position:0% +case you haven't had a chance to read it +I know they're kind of long um so some + + align:start position:0% +I know they're kind of long um so some + + + align:start position:0% +I know they're kind of long um so some +people were earlier asking me do I need + + align:start position:0% +people were earlier asking me do I need + + + align:start position:0% +people were earlier asking me do I need +to buy a new X um probably not so there + + align:start position:0% +to buy a new X um probably not so there + + + align:start position:0% +to buy a new X um probably not so there +might be one or two things you want to + + align:start position:0% +might be one or two things you want to + + + align:start position:0% +might be one or two things you want to +buy but generally the goal of daab is + + align:start position:0% +buy but generally the goal of daab is + + + align:start position:0% +buy but generally the goal of daab is +not to make yourself broke going to + + align:start position:0% +not to make yourself broke going to + + + align:start position:0% +not to make yourself broke going to +travel to a developing country um so + + align:start position:0% +travel to a developing country um so + + + align:start position:0% +travel to a developing country um so +very little needs to be bought new and + + align:start position:0% +very little needs to be bought new and + + + align:start position:0% +very little needs to be bought new and +pack lightly which is in direct + + align:start position:0% +pack lightly which is in direct + + + align:start position:0% +pack lightly which is in direct +contradiction to the two-page packing + + align:start position:0% +contradiction to the two-page packing + + + align:start position:0% +contradiction to the two-page packing +list that I provided you but basically + + align:start position:0% +list that I provided you but basically + + + align:start position:0% +list that I provided you but basically +that two-page packing list is the list + + align:start position:0% +that two-page packing list is the list + + + align:start position:0% +that two-page packing list is the list +of all things that someone at daab + + align:start position:0% +of all things that someone at daab + + + align:start position:0% +of all things that someone at daab +really likes bringing and so some people + + align:start position:0% +really likes bringing and so some people + + + align:start position:0% +really likes bringing and so some people +really value certain things other people + + align:start position:0% +really value certain things other people + + + align:start position:0% +really value certain things other people +bring value other things you sort of + + align:start position:0% +bring value other things you sort of + + + align:start position:0% +bring value other things you sort of +have to know yourself what are the + + align:start position:0% +have to know yourself what are the + + + align:start position:0% +have to know yourself what are the +objects that are going to be important + + align:start position:0% +objects that are going to be important + + + align:start position:0% +objects that are going to be important +for you to have and what are the ones + + align:start position:0% +for you to have and what are the ones + + + align:start position:0% +for you to have and what are the ones +that you can skip so there's just a + + align:start position:0% +that you can skip so there's just a + + + align:start position:0% +that you can skip so there's just a +couple that I have on that packing list + + align:start position:0% +couple that I have on that packing list + + + align:start position:0% +couple that I have on that packing list +that are in blue I didn't even put + + align:start position:0% +that are in blue I didn't even put + + + align:start position:0% +that are in blue I didn't even put +underwear in blue right just the ones + + align:start position:0% +underwear in blue right just the ones + + + align:start position:0% +underwear in blue right just the ones +like a flashlight that if you don't have + + align:start position:0% +like a flashlight that if you don't have + + + align:start position:0% +like a flashlight that if you don't have +it's going to be really hard for you to + + align:start position:0% +it's going to be really hard for you to + + + align:start position:0% +it's going to be really hard for you to +function so things like that you have to + + align:start position:0% +function so things like that you have to + + + align:start position:0% +function so things like that you have to +have everything else is sort of your + + align:start position:0% +have everything else is sort of your + + + align:start position:0% +have everything else is sort of your +call so if you don't have Tas you don't + + align:start position:0% +call so if you don't have Tas you don't + + + align:start position:0% +call so if you don't have Tas you don't +have boots you don't have whatever don't + + align:start position:0% +have boots you don't have whatever don't + + + align:start position:0% +have boots you don't have whatever don't +worry about it um don't go out and buy + + align:start position:0% +worry about it um don't go out and buy + + + align:start position:0% +worry about it um don't go out and buy +yourself a 200 pair of hiking boots um + + align:start position:0% +yourself a 200 pair of hiking boots um + + + align:start position:0% +yourself a 200 pair of hiking boots um +that you'll never wear again just for + + align:start position:0% +that you'll never wear again just for + + + align:start position:0% +that you'll never wear again just for +this trip that's not necessary um so + + align:start position:0% +this trip that's not necessary um so + + + align:start position:0% +this trip that's not necessary um so +pack lightly um with that being said it + + align:start position:0% +pack lightly um with that being said it + + + align:start position:0% +pack lightly um with that being said it +can be as cold as like 50° at night so + + align:start position:0% +can be as cold as like 50° at night so + + + align:start position:0% +can be as cold as like 50° at night so +you might want a light fleece or + + align:start position:0% +you might want a light fleece or + + + align:start position:0% +you might want a light fleece or +something like that and then in the + + align:start position:0% +something like that and then in the + + + align:start position:0% +something like that and then in the +middle of the day it's wicked hot and + + align:start position:0% +middle of the day it's wicked hot and + + + align:start position:0% +middle of the day it's wicked hot and +humid um relatively conservative dress + + align:start position:0% +humid um relatively conservative dress + + + align:start position:0% +humid um relatively conservative dress +again um for a lot of these things I'm + + align:start position:0% +again um for a lot of these things I'm + + + align:start position:0% +again um for a lot of these things I'm +asking you to be more conservative than + + align:start position:0% +asking you to be more conservative than + + + align:start position:0% +asking you to be more conservative than +you may see most people being not most + + align:start position:0% +you may see most people being not most + + + align:start position:0% +you may see most people being not most +but many people in Nicaragua being um + + align:start position:0% +but many people in Nicaragua being um + + + align:start position:0% +but many people in Nicaragua being um +because again we're representing MIT and + + align:start position:0% +because again we're representing MIT and + + + align:start position:0% +because again we're representing MIT and +daab and the Y yada and so we want to be + + align:start position:0% +daab and the Y yada and so we want to be + + + align:start position:0% +daab and the Y yada and so we want to be +respectful to the people who are on the + + align:start position:0% +respectful to the people who are on the + + + align:start position:0% +respectful to the people who are on the +conservative side in terms of dress Etc + + align:start position:0% +conservative side in terms of dress Etc + + + align:start position:0% +conservative side in terms of dress Etc +um toiletries so if you have any + + align:start position:0% +um toiletries so if you have any + + + align:start position:0% +um toiletries so if you have any +medications that you need to take you + + align:start position:0% +medications that you need to take you + + + align:start position:0% +medications that you need to take you +should take twice as many as you need + + align:start position:0% +should take twice as many as you need + + + align:start position:0% +should take twice as many as you need +and keep them in two separate places so + + align:start position:0% +and keep them in two separate places so + + + align:start position:0% +and keep them in two separate places so +that if a bag gets stolen or lost you + + align:start position:0% +that if a bag gets stolen or lost you + + + align:start position:0% +that if a bag gets stolen or lost you +have your meds um you definitely want to + + align:start position:0% +have your meds um you definitely want to + + + align:start position:0% +have your meds um you definitely want to +bring toilet paper or tissues or + + align:start position:0% +bring toilet paper or tissues or + + + align:start position:0% +bring toilet paper or tissues or +something like that you can use for + + align:start position:0% +something like that you can use for + + + align:start position:0% +something like that you can use for +toilet paper cuz not all places will + + align:start position:0% +toilet paper cuz not all places will + + + align:start position:0% +toilet paper cuz not all places will +have it um you won't be offered a towel + + align:start position:0% +have it um you won't be offered a towel + + + align:start position:0% +have it um you won't be offered a towel +so if you want to have a towel for + + align:start position:0% +so if you want to have a towel for + + + align:start position:0% +so if you want to have a towel for +showering which will be bucket showers + + align:start position:0% +showering which will be bucket showers + + + align:start position:0% +showering which will be bucket showers +um so taking a scoop of water from a + + align:start position:0% +um so taking a scoop of water from a + + + align:start position:0% +um so taking a scoop of water from a +bucket and pouring it on your head um + + align:start position:0% +bucket and pouring it on your head um + + + align:start position:0% +bucket and pouring it on your head um +you should bring one but I would bring a + + align:start position:0% +you should bring one but I would bring a + + + align:start position:0% +you should bring one but I would bring a +small one because they're pretty bulky + + align:start position:0% +small one because they're pretty bulky + + + align:start position:0% +small one because they're pretty bulky +um you'll definitely want bug repellent + + align:start position:0% +um you'll definitely want bug repellent + + + align:start position:0% +um you'll definitely want bug repellent +and sunscreen the sun is much stronger + + align:start position:0% +and sunscreen the sun is much stronger + + + align:start position:0% +and sunscreen the sun is much stronger +and um you will sunburn if you don't + + align:start position:0% +and um you will sunburn if you don't + + + align:start position:0% +and um you will sunburn if you don't +wear sunscreen if you're fair skinned um + + align:start position:0% +wear sunscreen if you're fair skinned um + + + align:start position:0% +wear sunscreen if you're fair skinned um +flashlight again is key having a photoc + + align:start position:0% +flashlight again is key having a photoc + + + align:start position:0% +flashlight again is key having a photoc +copy of your passport um bringing a + + align:start position:0% +copy of your passport um bringing a + + + align:start position:0% +copy of your passport um bringing a +notebook like I mentioned um and then + + align:start position:0% +notebook like I mentioned um and then + + + align:start position:0% +notebook like I mentioned um and then +nothing of value so you shouldn't be + + align:start position:0% +nothing of value so you shouldn't be + + + align:start position:0% +nothing of value so you shouldn't be +wearing your brass rats um you could + + align:start position:0% +wearing your brass rats um you could + + + align:start position:0% +wearing your brass rats um you could +skip earrings or wear really small + + align:start position:0% +skip earrings or wear really small + + + align:start position:0% +skip earrings or wear really small +subtle ones um cameras like a small + + align:start position:0% +subtle ones um cameras like a small + + + align:start position:0% +subtle ones um cameras like a small +junky point and shoot is fine but a dlsr + + align:start position:0% +junky point and shoot is fine but a dlsr + + + align:start position:0% +junky point and shoot is fine but a dlsr +is not ideal um again you'll see some + + align:start position:0% +is not ideal um again you'll see some + + + align:start position:0% +is not ideal um again you'll see some +people in Nicaragua with the lsrs but + + align:start position:0% +people in Nicaragua with the lsrs but + + + align:start position:0% +people in Nicaragua with the lsrs but +they're making the choice for themselves + + align:start position:0% +they're making the choice for themselves + + + align:start position:0% +they're making the choice for themselves +about having that and therefore bringing + + align:start position:0% +about having that and therefore bringing + + + align:start position:0% +about having that and therefore bringing +the potential crime associated with + + align:start position:0% +the potential crime associated with + + + align:start position:0% +the potential crime associated with +having a fancy device there and it's not + + align:start position:0% +having a fancy device there and it's not + + + align:start position:0% +having a fancy device there and it's not +fair for you to make that call for your + + align:start position:0% +fair for you to make that call for your + + + align:start position:0% +fair for you to make that call for your +entire team um on that camera yeah what + + align:start position:0% +entire team um on that camera yeah what + + + align:start position:0% +entire team um on that camera yeah what +kind of risk are you talking about like + + align:start position:0% +kind of risk are you talking about like + + + align:start position:0% +kind of risk are you talking about like +m is actually waterproof and shockproof + + align:start position:0% +m is actually waterproof and shockproof + + + align:start position:0% +m is actually waterproof and shockproof +or it theft + + align:start position:0% +or it theft + + + align:start position:0% +or it theft +theft so even if we so do you have a + + align:start position:0% +theft so even if we so do you have a + + + align:start position:0% +theft so even if we so do you have a +point do you have a waterproof sock + + align:start position:0% +point do you have a waterproof sock + + + align:start position:0% +point do you have a waterproof sock +prooof dlsr what's the dlsr there like + + align:start position:0% +prooof dlsr what's the dlsr there like + + + align:start position:0% +prooof dlsr what's the dlsr there like +the big no not the big one so a point + + align:start position:0% +the big no not the big one so a point + + + align:start position:0% +the big no not the big one so a point +shoot totally fine yeah yeah so this is + + align:start position:0% +shoot totally fine yeah yeah so this is + + + align:start position:0% +shoot totally fine yeah yeah so this is +what I'm saying so like a camera that's + + align:start position:0% +what I'm saying so like a camera that's + + + align:start position:0% +what I'm saying so like a camera that's +this size is fine a camera that's that + + align:start position:0% +this size is fine a camera that's that + + + align:start position:0% +this size is fine a camera that's that +size not + + align:start position:0% +size not + + + align:start position:0% +size not +fine is what I'm saying um ones that + + align:start position:0% +fine is what I'm saying um ones that + + + align:start position:0% +fine is what I'm saying um ones that +have like the switch out a lenses a dlsr + + align:start position:0% +have like the switch out a lenses a dlsr + + + align:start position:0% +have like the switch out a lenses a dlsr +you know fancy nice camera that's what + + align:start position:0% +you know fancy nice camera that's what + + + align:start position:0% +you know fancy nice camera that's what +I'm asking you not to take point and + + align:start position:0% +I'm asking you not to take point and + + + align:start position:0% +I'm asking you not to take point and +shoot you should totally take + + align:start position:0% +shoot you should totally take + + + align:start position:0% +shoot you should totally take +um and then yeah laptops um your team + + align:start position:0% +um and then yeah laptops um your team + + + align:start position:0% +um and then yeah laptops um your team +probably shouldn't bring any laptops if + + align:start position:0% +probably shouldn't bring any laptops if + + + align:start position:0% +probably shouldn't bring any laptops if +you need to you should bring one um but + + align:start position:0% +you need to you should bring one um but + + + align:start position:0% +you need to you should bring one um but +definitely not more than that um yeah do + + align:start position:0% +definitely not more than that um yeah do + + + align:start position:0% +definitely not more than that um yeah do +you recommend bringing more than one + + align:start position:0% +you recommend bringing more than one + + + align:start position:0% +you recommend bringing more than one +card for camera yes so I recommend + + align:start position:0% +card for camera yes so I recommend + + + align:start position:0% +card for camera yes so I recommend +bringing as much memory and battery + + align:start position:0% +bringing as much memory and battery + + + align:start position:0% +bringing as much memory and battery +charging capability as you can um both + + align:start position:0% +charging capability as you can um both + + + align:start position:0% +charging capability as you can um both +because you'll have limited access to + + align:start position:0% +because you'll have limited access to + + + align:start position:0% +because you'll have limited access to +electricity for battery charging and + + align:start position:0% +electricity for battery charging and + + + align:start position:0% +electricity for battery charging and +then you may be taking a lot of pictures + + align:start position:0% +then you may be taking a lot of pictures + + + align:start position:0% +then you may be taking a lot of pictures +and um you may not have a laptop and be + + align:start position:0% +and um you may not have a laptop and be + + + align:start position:0% +and um you may not have a laptop and be +able to download them until you get + + align:start position:0% + + + + align:start position:0% + +home I'm not sure why + + align:start position:0% + + + + align:start position:0% + +that's + + align:start position:0% +that's + + + align:start position:0% +that's +yeah um + + align:start position:0% +yeah um + + + align:start position:0% +yeah um +so the thing that's complicated is so + + align:start position:0% +so the thing that's complicated is so + + + align:start position:0% +so the thing that's complicated is so +every trip leader will have a cell phone + + align:start position:0% +every trip leader will have a cell phone + + + align:start position:0% +every trip leader will have a cell phone +with them so for emergencies there's a + + align:start position:0% +with them so for emergencies there's a + + + align:start position:0% +with them so for emergencies there's a +way to call the states or a way to call + + align:start position:0% +way to call the states or a way to call + + + align:start position:0% +way to call the states or a way to call +within your country or whatever you need + + align:start position:0% +within your country or whatever you need + + + align:start position:0% +within your country or whatever you need +um I can't see why you'd need a cell + + align:start position:0% +um I can't see why you'd need a cell + + + align:start position:0% +um I can't see why you'd need a cell +phone um like it might be nice to have + + align:start position:0% +phone um like it might be nice to have + + + align:start position:0% +phone um like it might be nice to have +during your layovers or whatever so you + + align:start position:0% +during your layovers or whatever so you + + + align:start position:0% +during your layovers or whatever so you +might want to bring it for that reason + + align:start position:0% +might want to bring it for that reason + + + align:start position:0% +might want to bring it for that reason +but if it's anything at all nice and I'm + + align:start position:0% +but if it's anything at all nice and I'm + + + align:start position:0% +but if it's anything at all nice and I'm +concluding like my junkie phone is nice + + align:start position:0% +concluding like my junkie phone is nice + + + align:start position:0% +concluding like my junkie phone is nice +um but anything that looks fancier than + + align:start position:0% +um but anything that looks fancier than + + + align:start position:0% +um but anything that looks fancier than +like flip phones that people had like 10 + + align:start position:0% +like flip phones that people had like 10 + + + align:start position:0% +like flip phones that people had like 10 +years ago um should never be visible in + + align:start position:0% +years ago um should never be visible in + + + align:start position:0% +years ago um should never be visible in +Nicaragua so if you're going to bring it + + align:start position:0% +Nicaragua so if you're going to bring it + + + align:start position:0% +Nicaragua so if you're going to bring it +pack it in the bottom of your bag you + + align:start position:0% +pack it in the bottom of your bag you + + + align:start position:0% +pack it in the bottom of your bag you +know as soon as you get to Miami um and + + align:start position:0% +know as soon as you get to Miami um and + + + align:start position:0% +know as soon as you get to Miami um and +leave it there um rather than taking it + + align:start position:0% +leave it there um rather than taking it + + + align:start position:0% +leave it there um rather than taking it +out so and again like you'll see a few + + align:start position:0% +out so and again like you'll see a few + + + align:start position:0% +out so and again like you'll see a few +people with iPhones but in Nicaragua but + + align:start position:0% +people with iPhones but in Nicaragua but + + + align:start position:0% +people with iPhones but in Nicaragua but +they're taking a risk and you shouldn't + + align:start position:0% +they're taking a risk and you shouldn't + + + align:start position:0% +they're taking a risk and you shouldn't +have yours out and about while you're + + align:start position:0% +have yours out and about while you're + + + align:start position:0% +have yours out and about while you're +there um but the one thing is that most + + align:start position:0% +there um but the one thing is that most + + + align:start position:0% +there um but the one thing is that most +of you are leaving super super early on + + align:start position:0% +of you are leaving super super early on + + + align:start position:0% +of you are leaving super super early on +Sunday so you do want to have your cell + + align:start position:0% +Sunday so you do want to have your cell + + + align:start position:0% +Sunday so you do want to have your cell +phone out that morning that middle of + + align:start position:0% +phone out that morning that middle of + + + align:start position:0% +phone out that morning that middle of +the night just to make sure you're awake + + align:start position:0% +the night just to make sure you're awake + + + align:start position:0% +the night just to make sure you're awake +um I don't know at 3:00 am like I feel + + align:start position:0% +um I don't know at 3:00 am like I feel + + + align:start position:0% +um I don't know at 3:00 am like I feel +like most of you probably won't even + + align:start position:0% +like most of you probably won't even + + + align:start position:0% +like most of you probably won't even +sleep right like I don't I don't go to + + align:start position:0% +sleep right like I don't I don't go to + + + align:start position:0% +sleep right like I don't I don't go to +sleep if I have to leave at 3: um but + + align:start position:0% +sleep if I have to leave at 3: um but + + + align:start position:0% +sleep if I have to leave at 3: um but +yeah we want to make sure you get there + + align:start position:0% +yeah we want to make sure you get there + + + align:start position:0% +yeah we want to make sure you get there +um so one other thing you want to bring + + align:start position:0% +um so one other thing you want to bring + + + align:start position:0% +um so one other thing you want to bring +is gifts for your Community Partners um + + align:start position:0% +is gifts for your Community Partners um + + + align:start position:0% +is gifts for your Community Partners um +and so some criteria for what makes a + + align:start position:0% +and so some criteria for what makes a + + + align:start position:0% +and so some criteria for what makes a +good gift is one that is not + + align:start position:0% +good gift is one that is not + + + align:start position:0% +good gift is one that is not +extravagantly over-the toop expensive + + align:start position:0% +extravagantly over-the toop expensive + + + align:start position:0% +extravagantly over-the toop expensive +because it can sort of set up + + align:start position:0% +because it can sort of set up + + + align:start position:0% +because it can sort of set up +a the disparity between wealth can be + + align:start position:0% +a the disparity between wealth can be + + + align:start position:0% +a the disparity between wealth can be +more um significant and make people feel + + align:start position:0% +more um significant and make people feel + + + align:start position:0% +more um significant and make people feel +uncomfortable um also you may well be on + + align:start position:0% +uncomfortable um also you may well be on + + + align:start position:0% +uncomfortable um also you may well be on +a budget and I don't want you to go + + align:start position:0% +a budget and I don't want you to go + + + align:start position:0% +a budget and I don't want you to go +broke buying gifts for your family um + + align:start position:0% +broke buying gifts for your family um + + + align:start position:0% +broke buying gifts for your family um +other things are will they actually use + + align:start position:0% +other things are will they actually use + + + align:start position:0% +other things are will they actually use +it will this just become some piece of + + align:start position:0% +it will this just become some piece of + + + align:start position:0% +it will this just become some piece of +trash that um adds trash to the + + align:start position:0% +trash that um adds trash to the + + + align:start position:0% +trash that um adds trash to the +community um in places where they're + + align:start position:0% +community um in places where they're + + + align:start position:0% +community um in places where they're +relatively pristine and we or not but we + + align:start position:0% +relatively pristine and we or not but we + + + align:start position:0% +relatively pristine and we or not but we +don't want to be adding to the trash + + align:start position:0% +don't want to be adding to the trash + + + align:start position:0% +don't want to be adding to the trash +load Etc um so daab has a few things + + align:start position:0% +load Etc um so daab has a few things + + + align:start position:0% +load Etc um so daab has a few things +that we um buy that are branded as daab + + align:start position:0% +that we um buy that are branded as daab + + + align:start position:0% +that we um buy that are branded as daab +objects that you can um buy from daab so + + align:start position:0% +objects that you can um buy from daab so + + + align:start position:0% +objects that you can um buy from daab so +gifts are not something that daab pays + + align:start position:0% +gifts are not something that daab pays + + + align:start position:0% +gifts are not something that daab pays +for it's something that you pay for as a + + align:start position:0% +for it's something that you pay for as a + + + align:start position:0% +for it's something that you pay for as a +team or an individual um because they're + + align:start position:0% +team or an individual um because they're + + + align:start position:0% +team or an individual um because they're +from you um and so it's up to you to + + align:start position:0% +from you um and so it's up to you to + + + align:start position:0% +from you um and so it's up to you to +decide how much but I think something is + + align:start position:0% +decide how much but I think something is + + + align:start position:0% +decide how much but I think something is +appropriate um so Sports bottles are $5 + + align:start position:0% +appropriate um so Sports bottles are $5 + + + align:start position:0% +appropriate um so Sports bottles are $5 +these hats maybe six or 8 um hats I + + align:start position:0% +these hats maybe six or 8 um hats I + + + align:start position:0% +these hats maybe six or 8 um hats I +think are a pretty good gift because + + align:start position:0% +think are a pretty good gift because + + + align:start position:0% +think are a pretty good gift because +people can wear them and they like them + + align:start position:0% +people can wear them and they like them + + + align:start position:0% +people can wear them and they like them +and a lot of people wear baseball caps + + align:start position:0% +and a lot of people wear baseball caps + + + align:start position:0% +and a lot of people wear baseball caps +um but don't bring them Red Sox caps cuz + + align:start position:0% +um but don't bring them Red Sox caps cuz + + + align:start position:0% +um but don't bring them Red Sox caps cuz +most them like + + align:start position:0% +most them like + + + align:start position:0% +most them like +Yankees and those are the only two teams + + align:start position:0% +Yankees and those are the only two teams + + + align:start position:0% +Yankees and those are the only two teams +that are basically known from what I saw + + align:start position:0% +that are basically known from what I saw + + + align:start position:0% +that are basically known from what I saw +um we also have these little flashlights + + align:start position:0% +um we also have these little flashlights + + + align:start position:0% +um we also have these little flashlights +um oh I think the battery is blocked so + + align:start position:0% +um oh I think the battery is blocked so + + + align:start position:0% +um oh I think the battery is blocked so +I can't turn it on but yeah um the the + + align:start position:0% +I can't turn it on but yeah um the the + + + align:start position:0% +I can't turn it on but yeah um the the +challenge with these flashlights it + + align:start position:0% +challenge with these flashlights it + + + align:start position:0% +challenge with these flashlights it +means the battery has to be replaced and + + align:start position:0% +means the battery has to be replaced and + + + align:start position:0% +means the battery has to be replaced and +things like that so it's a mixed bag um + + align:start position:0% +things like that so it's a mixed bag um + + + align:start position:0% +things like that so it's a mixed bag um +how valuable it is but they're they're + + align:start position:0% +how valuable it is but they're they're + + + align:start position:0% +how valuable it is but they're they're +fun um these little drawstring bags um + + align:start position:0% +fun um these little drawstring bags um + + + align:start position:0% +fun um these little drawstring bags um +which people like um I often bring + + align:start position:0% +which people like um I often bring + + + align:start position:0% +which people like um I often bring +chocolate to share with my like I'll + + align:start position:0% +chocolate to share with my like I'll + + + align:start position:0% +chocolate to share with my like I'll +bring a couple hats to bring for like + + align:start position:0% +bring a couple hats to bring for like + + + align:start position:0% +bring a couple hats to bring for like +someone like Lindsay or someone who's + + align:start position:0% +someone like Lindsay or someone who's + + + align:start position:0% +someone like Lindsay or someone who's +helping you a lot and then for the + + align:start position:0% +helping you a lot and then for the + + + align:start position:0% +helping you a lot and then for the +family just bring chocolate that you can + + align:start position:0% +family just bring chocolate that you can + + + align:start position:0% +family just bring chocolate that you can +share with them um Trader Joe sells + + align:start position:0% +share with them um Trader Joe sells + + + align:start position:0% +share with them um Trader Joe sells +pretty good pretty cheap chocolate that + + align:start position:0% +pretty good pretty cheap chocolate that + + + align:start position:0% +pretty good pretty cheap chocolate that +travels pretty well some chocolate melts + + align:start position:0% +travels pretty well some chocolate melts + + + align:start position:0% +travels pretty well some chocolate melts +really easily and that's not ideal for + + align:start position:0% +really easily and that's not ideal for + + + align:start position:0% +really easily and that's not ideal for +given how hot it is um but some of the + + align:start position:0% +given how hot it is um but some of the + + + align:start position:0% +given how hot it is um but some of the +nicer chocolate comes in like three + + align:start position:0% +nicer chocolate comes in like three + + + align:start position:0% +nicer chocolate comes in like three +packs for like two bucks um and just + + align:start position:0% +packs for like two bucks um and just + + + align:start position:0% +packs for like two bucks um and just +sharing that with your family it means + + align:start position:0% +sharing that with your family it means + + + align:start position:0% +sharing that with your family it means +something you can share with all the + + align:start position:0% +something you can share with all the + + + align:start position:0% +something you can share with all the +members um and is nice and is from your + + align:start position:0% +members um and is nice and is from your + + + align:start position:0% +members um and is nice and is from your +home country chocolate in Nicaragua in + + align:start position:0% +home country chocolate in Nicaragua in + + + align:start position:0% +home country chocolate in Nicaragua in +my opinion is far inferior to Chate in + + align:start position:0% +my opinion is far inferior to Chate in + + + align:start position:0% +my opinion is far inferior to Chate in +the states um and uh a lot of people I + + align:start position:0% +the states um and uh a lot of people I + + + align:start position:0% +the states um and uh a lot of people I +know agree um and so something like that + + align:start position:0% +know agree um and so something like that + + + align:start position:0% +know agree um and so something like that +is also appropriate so are there any + + align:start position:0% +is also appropriate so are there any + + + align:start position:0% +is also appropriate so are there any +questions on gifts want to get any of + + align:start position:0% +questions on gifts want to get any of + + + align:start position:0% +questions on gifts want to get any of +these um so I'm trying to leave a little + + align:start position:0% +these um so I'm trying to leave a little + + + align:start position:0% +these um so I'm trying to leave a little +time at the end of this class so that + + align:start position:0% +time at the end of this class so that + + + align:start position:0% +time at the end of this class so that +your team can make a list of all the + + align:start position:0% +your team can make a list of all the + + + align:start position:0% +your team can make a list of all the +things you need from daab and these gift + + align:start position:0% +things you need from daab and these gift + + + align:start position:0% +things you need from daab and these gift +things are among + + align:start position:0% +things are among + + + align:start position:0% +things are among +them um in terms of money that you might + + align:start position:0% +them um in terms of money that you might + + + align:start position:0% +them um in terms of money that you might +need uh so you should bring your Charlie + + align:start position:0% +need uh so you should bring your Charlie + + + align:start position:0% +need uh so you should bring your Charlie +card because you'll probably be coming + + align:start position:0% +card because you'll probably be coming + + + align:start position:0% +card because you'll probably be coming +back on the tea if not going there um + + align:start position:0% +back on the tea if not going there um + + + align:start position:0% +back on the tea if not going there um +there's an entry Visa cost to get into + + align:start position:0% +there's an entry Visa cost to get into + + + align:start position:0% +there's an entry Visa cost to get into +Nicaragua of $10 and if you just have a + + align:start position:0% +Nicaragua of $10 and if you just have a + + + align:start position:0% +Nicaragua of $10 and if you just have a +$10 bill on you it's nice to not have to + + align:start position:0% +$10 bill on you it's nice to not have to + + + align:start position:0% +$10 bill on you it's nice to not have to +deal with the Customs agent making + + align:start position:0% +deal with the Customs agent making + + + align:start position:0% +deal with the Customs agent making +change um if you're bringing cash so you + + align:start position:0% +change um if you're bringing cash so you + + + align:start position:0% +change um if you're bringing cash so you +may want some cash um for food that's + + align:start position:0% +may want some cash um for food that's + + + align:start position:0% +may want some cash um for food that's +not already prepaid um which you guys + + align:start position:0% +not already prepaid um which you guys + + + align:start position:0% +not already prepaid um which you guys +will reimburse us for after the trip or + + align:start position:0% +will reimburse us for after the trip or + + + align:start position:0% +will reimburse us for after the trip or +um for gifts for yourself to bring home + + align:start position:0% +um for gifts for yourself to bring home + + + align:start position:0% +um for gifts for yourself to bring home +to for yourself or family members um at + + align:start position:0% +to for yourself or family members um at + + + align:start position:0% +to for yourself or family members um at +the airport if not while you're + + align:start position:0% +the airport if not while you're + + + align:start position:0% +the airport if not while you're +traveling there'll be opportunities to + + align:start position:0% +traveling there'll be opportunities to + + + align:start position:0% +traveling there'll be opportunities to +do a little shopping um so you shouldn't + + align:start position:0% +do a little shopping um so you shouldn't + + + align:start position:0% +do a little shopping um so you shouldn't +bring anything bigger than a $20 bill um + + align:start position:0% +bring anything bigger than a $20 bill um + + + align:start position:0% +bring anything bigger than a $20 bill um +and smaller bills are nicer generally + + align:start position:0% +and smaller bills are nicer generally + + + align:start position:0% +and smaller bills are nicer generally +because it's hard for people to make + + align:start position:0% +because it's hard for people to make + + + align:start position:0% +because it's hard for people to make +change um but the Bills should be in + + align:start position:0% +change um but the Bills should be in + + + align:start position:0% +change um but the Bills should be in +decent condition if they're really ratty + + align:start position:0% +decent condition if they're really ratty + + + align:start position:0% +decent condition if they're really ratty +people won't take them um and then if + + align:start position:0% +people won't take them um and then if + + + align:start position:0% +people won't take them um and then if +you expect to be needing to use your + + align:start position:0% +you expect to be needing to use your + + + align:start position:0% +you expect to be needing to use your +bank or credit card debit card for + + align:start position:0% +bank or credit card debit card for + + + align:start position:0% +bank or credit card debit card for +either for general just getting money + + align:start position:0% +either for general just getting money + + + align:start position:0% +either for general just getting money +out of an ATM or for an emergency you + + align:start position:0% +out of an ATM or for an emergency you + + + align:start position:0% +out of an ATM or for an emergency you +should call them to warn them that + + align:start position:0% +should call them to warn them that + + + align:start position:0% +should call them to warn them that +you're traveling so that if you do need + + align:start position:0% +you're traveling so that if you do need + + + align:start position:0% +you're traveling so that if you do need +it you can CU usually they'll block any + + align:start position:0% +it you can CU usually they'll block any + + + align:start position:0% +it you can CU usually they'll block any +charges and unless youve told them ahead + + align:start position:0% +charges and unless youve told them ahead + + + align:start position:0% +charges and unless youve told them ahead +of + + align:start position:0% + + + + align:start position:0% + +time um some tips so you should assume + + align:start position:0% +time um some tips so you should assume + + + align:start position:0% +time um some tips so you should assume +that drinking water is unsafe um which + + align:start position:0% +that drinking water is unsafe um which + + + align:start position:0% +that drinking water is unsafe um which +means that any vegetables or fruits that + + align:start position:0% +means that any vegetables or fruits that + + + align:start position:0% +means that any vegetables or fruits that +aren't cooked are also unsafe because + + align:start position:0% +aren't cooked are also unsafe because + + + align:start position:0% +aren't cooked are also unsafe because +they were probably washed in that unsafe + + align:start position:0% +they were probably washed in that unsafe + + + align:start position:0% +they were probably washed in that unsafe +drinking water um so uh each team me + + align:start position:0% +drinking water um so uh each team me + + + align:start position:0% +drinking water um so uh each team me +team trip leader will have a water + + align:start position:0% +team trip leader will have a water + + + align:start position:0% +team trip leader will have a water +filter that you guys can use to filter + + align:start position:0% +filter that you guys can use to filter + + + align:start position:0% +filter that you guys can use to filter +your own water which means you really do + + align:start position:0% +your own water which means you really do + + + align:start position:0% +your own water which means you really do +want to bring a water bottle so that you + + align:start position:0% +want to bring a water bottle so that you + + + align:start position:0% +want to bring a water bottle so that you +can um clean have clean water in that + + align:start position:0% +can um clean have clean water in that + + + align:start position:0% +can um clean have clean water in that +water bottle um but this is definitely + + align:start position:0% +water bottle um but this is definitely + + + align:start position:0% +water bottle um but this is definitely +something to be cautious on so you stay + + align:start position:0% +something to be cautious on so you stay + + + align:start position:0% +something to be cautious on so you stay +healthy for the trip because it's such a + + align:start position:0% +healthy for the trip because it's such a + + + align:start position:0% +healthy for the trip because it's such a +short trip that if you get sick for a + + align:start position:0% +short trip that if you get sick for a + + + align:start position:0% +short trip that if you get sick for a +few days that's half your + + align:start position:0% +few days that's half your + + + align:start position:0% +few days that's half your +trip um NE nothing nothing expensive at + + align:start position:0% +trip um NE nothing nothing expensive at + + + align:start position:0% +trip um NE nothing nothing expensive at +least in site or brought so you know + + align:start position:0% +least in site or brought so you know + + + align:start position:0% +least in site or brought so you know +like a brass rat or nice jewelry or + + align:start position:0% +like a brass rat or nice jewelry or + + + align:start position:0% +like a brass rat or nice jewelry or +watch or whatever leave here if you need + + align:start position:0% +watch or whatever leave here if you need + + + align:start position:0% +watch or whatever leave here if you need +to bring that cell phone so you have it + + align:start position:0% +to bring that cell phone so you have it + + + align:start position:0% +to bring that cell phone so you have it +while you're in the states while you're + + align:start position:0% +while you're in the states while you're + + + align:start position:0% +while you're in the states while you're +traveling just keep it hidden in your + + align:start position:0% +traveling just keep it hidden in your + + + align:start position:0% +traveling just keep it hidden in your +bag so that um it's not brought + + align:start position:0% +bag so that um it's not brought + + + align:start position:0% +bag so that um it's not brought +attention to being brought attention to + + align:start position:0% +attention to being brought attention to + + + align:start position:0% +attention to being brought attention to +at all um you should always be travel in + + align:start position:0% +at all um you should always be travel in + + + align:start position:0% +at all um you should always be travel in +groups ideally um but especially at + + align:start position:0% +groups ideally um but especially at + + + align:start position:0% +groups ideally um but especially at +night um there's going to be some cases + + align:start position:0% +night um there's going to be some cases + + + align:start position:0% +night um there's going to be some cases +where that'll be tricky but um do your + + align:start position:0% +where that'll be tricky but um do your + + + align:start position:0% +where that'll be tricky but um do your +best to be as safe as possible um as I + + align:start position:0% +best to be as safe as possible um as I + + + align:start position:0% +best to be as safe as possible um as I +mentioned flexibility and Patience are + + align:start position:0% +mentioned flexibility and Patience are + + + align:start position:0% +mentioned flexibility and Patience are +really great assets to have um so just + + align:start position:0% +really great assets to have um so just + + + align:start position:0% +really great assets to have um so just +sort of go in not expecting to be as + + align:start position:0% +sort of go in not expecting to be as + + + align:start position:0% +sort of go in not expecting to be as +efficient or effective as you NE + + align:start position:0% +efficient or effective as you NE + + + align:start position:0% +efficient or effective as you NE +necessarily hoped and sort of expect + + align:start position:0% +necessarily hoped and sort of expect + + + align:start position:0% +necessarily hoped and sort of expect +that things are going to change at the + + align:start position:0% +that things are going to change at the + + + align:start position:0% +that things are going to change at the +last minute and that'll help make the + + align:start position:0% +last minute and that'll help make the + + + align:start position:0% +last minute and that'll help make the +trip more fun rather than frustrating um + + align:start position:0% +trip more fun rather than frustrating um + + + align:start position:0% +trip more fun rather than frustrating um +and then managing expectations with the + + align:start position:0% +and then managing expectations with the + + + align:start position:0% +and then managing expectations with the +Community Partners um it's really easy + + align:start position:0% +Community Partners um it's really easy + + + align:start position:0% +Community Partners um it's really easy +for Community Partners to be like when + + align:start position:0% +for Community Partners to be like when + + + align:start position:0% +for Community Partners to be like when +are you coming back and you're so pumped + + align:start position:0% +are you coming back and you're so pumped + + + align:start position:0% +are you coming back and you're so pumped +and you're having such a great time and + + align:start position:0% +and you're having such a great time and + + + align:start position:0% +and you're having such a great time and +you're like I'll be back this summer + + align:start position:0% +you're like I'll be back this summer + + + align:start position:0% +you're like I'll be back this summer +like not thinking about well actually I + + align:start position:0% +like not thinking about well actually I + + + align:start position:0% +like not thinking about well actually I +have that internship at whoever and I'm + + align:start position:0% +have that internship at whoever and I'm + + + align:start position:0% +have that internship at whoever and I'm +not going to be back this summer and may + + align:start position:0% +not going to be back this summer and may + + + align:start position:0% +not going to be back this summer and may +never be back and so you don't want to + + align:start position:0% +never be back and so you don't want to + + + align:start position:0% +never be back and so you don't want to +make any promises that you can't keep + + align:start position:0% +make any promises that you can't keep + + + align:start position:0% +make any promises that you can't keep +that's really important um because that + + align:start position:0% +that's really important um because that + + + align:start position:0% +that's really important um because that +can ruin our relationship with our + + align:start position:0% +can ruin our relationship with our + + + align:start position:0% +can ruin our relationship with our +Community + + align:start position:0% +Community + + + align:start position:0% +Community +Partners um so just a reminder a few of + + align:start position:0% +Partners um so just a reminder a few of + + + align:start position:0% +Partners um so just a reminder a few of +you still owe me at least some of these + + align:start position:0% +you still owe me at least some of these + + + align:start position:0% +you still owe me at least some of these +things and so please get them to me + + align:start position:0% +things and so please get them to me + + + align:start position:0% +things and so please get them to me +today or tell me why you can't and what + + align:start position:0% +today or tell me why you can't and what + + + align:start position:0% +today or tell me why you can't and what +you're going to do if you haven't + + align:start position:0% +you're going to do if you haven't + + + align:start position:0% +you're going to do if you haven't +already um and so for the remainder of + + align:start position:0% +already um and so for the remainder of + + + align:start position:0% +already um and so for the remainder of +the class um I need to do micro + + align:start position:0% +the class um I need to do micro + + + align:start position:0% +the class um I need to do micro +interviews with everyone who's traveling + + align:start position:0% +interviews with everyone who's traveling + + + align:start position:0% +interviews with everyone who's traveling +um it's just a daab thing that we do we + + align:start position:0% +um it's just a daab thing that we do we + + + align:start position:0% +um it's just a daab thing that we do we +just talk oneon-one really briefly + + align:start position:0% +just talk oneon-one really briefly + + + align:start position:0% +just talk oneon-one really briefly +um you may want to revise your plan a + + align:start position:0% +um you may want to revise your plan a + + + align:start position:0% +um you may want to revise your plan a +little bit based on feedback from the + + align:start position:0% +little bit based on feedback from the + + + align:start position:0% +little bit based on feedback from the +presentations um you probably want to + + align:start position:0% +presentations um you probably want to + + + align:start position:0% +presentations um you probably want to +talk in your group about how much + + align:start position:0% +talk in your group about how much + + + align:start position:0% +talk in your group about how much +checked luggage you're having versus + + align:start position:0% +checked luggage you're having versus + + + align:start position:0% +checked luggage you're having versus +carryon who's carrying what for any + + align:start position:0% +carryon who's carrying what for any + + + align:start position:0% +carryon who's carrying what for any +bulky items you have have things that + + align:start position:0% +bulky items you have have things that + + + align:start position:0% +bulky items you have have things that +you might need from daab I need you to + + align:start position:0% +you might need from daab I need you to + + + align:start position:0% +you might need from daab I need you to +tell me by the end of class today so you + + align:start position:0% +tell me by the end of class today so you + + + align:start position:0% +tell me by the end of class today so you +might need tools you might need cameras + + align:start position:0% +might need tools you might need cameras + + + align:start position:0% +might need tools you might need cameras +we have some that we can lend um + + align:start position:0% +we have some that we can lend um + + + align:start position:0% +we have some that we can lend um +mosquito Nets hammocks other it'd be + + align:start position:0% +mosquito Nets hammocks other it'd be + + + align:start position:0% +mosquito Nets hammocks other it'd be +nice if at least a few people have + + align:start position:0% +nice if at least a few people have + + + align:start position:0% +nice if at least a few people have +cameras so that um you can get different + + align:start position:0% +cameras so that um you can get different + + + align:start position:0% +cameras so that um you can get different +angles of shots when you're all taking + + align:start position:0% +angles of shots when you're all taking + + + align:start position:0% +angles of shots when you're all taking +pictures together and also um if one + + align:start position:0% +pictures together and also um if one + + + align:start position:0% +pictures together and also um if one +dies you're not unable to take pictures + + align:start position:0% +dies you're not unable to take pictures + + + align:start position:0% +dies you're not unable to take pictures +because pictures are really important + + align:start position:0% +because pictures are really important + + + align:start position:0% +because pictures are really important +for the projects um and then anything + + align:start position:0% +for the projects um and then anything + + + align:start position:0% +for the projects um and then anything +else you might need + + align:start position:0% +else you might need + + + align:start position:0% +else you might need +so are there any questions about all + + align:start position:0% + + + + align:start position:0% + +that okay cool \ No newline at end of file diff --git a/Wb34zGvpC3E.txt b/Wb34zGvpC3E.txt new file mode 100644 index 0000000000000000000000000000000000000000..d95e8ff13ada9dba8e247c1aa9b70da3dd9121fa --- /dev/null +++ b/Wb34zGvpC3E.txt @@ -0,0 +1,9024 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +to view additional materials from + + align:start position:0% +to view additional materials from + + + align:start position:0% +to view additional materials from +hundreds of MIT courses visit MIT open + + align:start position:0% +hundreds of MIT courses visit MIT open + + + align:start position:0% +hundreds of MIT courses visit MIT open +courseware at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu let's see a couple of + + align:start position:0% +ocw.mit.edu let's see a couple of + + + align:start position:0% +ocw.mit.edu let's see a couple of +announcements uh tomorrow there'll be a + + align:start position:0% +announcements uh tomorrow there'll be a + + + align:start position:0% +announcements uh tomorrow there'll be a +quiz 6 based on homework 6 just on the + + align:start position:0% +quiz 6 based on homework 6 just on the + + + align:start position:0% +quiz 6 based on homework 6 just on the +um crystallography there's a little bit + + align:start position:0% +um crystallography there's a little bit + + + align:start position:0% +um crystallography there's a little bit +at the end of homework six on X-rays and + + align:start position:0% +at the end of homework six on X-rays and + + + align:start position:0% +at the end of homework six on X-rays and +we will just start to talk about x-rays + + align:start position:0% +we will just start to talk about x-rays + + + align:start position:0% +we will just start to talk about x-rays +today so I think that uh we'll leave + + align:start position:0% +today so I think that uh we'll leave + + + align:start position:0% +today so I think that uh we'll leave +that out so just be based on + + align:start position:0% +that out so just be based on + + + align:start position:0% +that out so just be based on +crystallography um and I've asked the + + align:start position:0% +crystallography um and I've asked the + + + align:start position:0% +crystallography um and I've asked the +recitation instructors to administer the + + align:start position:0% +recitation instructors to administer the + + + align:start position:0% +recitation instructors to administer the +test at the end of the period so you can + + align:start position:0% +test at the end of the period so you can + + + align:start position:0% +test at the end of the period so you can +have some chance to ask uh + + align:start position:0% +have some chance to ask uh + + + align:start position:0% +have some chance to ask uh +questions um last day we talked about uh + + align:start position:0% +questions um last day we talked about uh + + + align:start position:0% +questions um last day we talked about uh +crystallography we were introduced to + + align:start position:0% +crystallography we were introduced to + + + align:start position:0% +crystallography we were introduced to +the seven Crystal systems and the 14 bra + + align:start position:0% +the seven Crystal systems and the 14 bra + + + align:start position:0% +the seven Crystal systems and the 14 bra +lates which are showing up on the uh + + align:start position:0% +lates which are showing up on the uh + + + align:start position:0% +lates which are showing up on the uh +slide taken from the lecture notes and + + align:start position:0% +slide taken from the lecture notes and + + + align:start position:0% +slide taken from the lecture notes and +we saw that if we wanted to describe the + + align:start position:0% +we saw that if we wanted to describe the + + + align:start position:0% +we saw that if we wanted to describe the +arrangement of atoms in a crystal we + + align:start position:0% +arrangement of atoms in a crystal we + + + align:start position:0% +arrangement of atoms in a crystal we +could do so by combining the notion of + + align:start position:0% +could do so by combining the notion of + + + align:start position:0% +could do so by combining the notion of +the brav latus of which there are 14 + + align:start position:0% +the brav latus of which there are 14 + + + align:start position:0% +the brav latus of which there are 14 +distinct types with a basis the basis + + align:start position:0% +distinct types with a basis the basis + + + align:start position:0% +distinct types with a basis the basis +could be a single atom could be a group + + align:start position:0% +could be a single atom could be a group + + + align:start position:0% +could be a single atom could be a group +of atoms could be an ion pair could be + + align:start position:0% +of atoms could be an ion pair could be + + + align:start position:0% +of atoms could be an ion pair could be +uh atom pair and uh we saw that got us + + align:start position:0% +uh atom pair and uh we saw that got us + + + align:start position:0% +uh atom pair and uh we saw that got us +through an elaborate set of uh crystals + + align:start position:0% +through an elaborate set of uh crystals + + + align:start position:0% +through an elaborate set of uh crystals +and then towards the end we focused on + + align:start position:0% +and then towards the end we focused on + + + align:start position:0% +and then towards the end we focused on +on cubic crystals because cubic crystals + + align:start position:0% +on cubic crystals because cubic crystals + + + align:start position:0% +on cubic crystals because cubic crystals +are representative of a large number of + + align:start position:0% +are representative of a large number of + + + align:start position:0% +are representative of a large number of +metals in the periodic table and it's + + align:start position:0% +metals in the periodic table and it's + + + align:start position:0% +metals in the periodic table and it's +much more tractable mathematically so + + align:start position:0% +much more tractable mathematically so + + + align:start position:0% +much more tractable mathematically so +we're going to focus on cubic crystals + + align:start position:0% +we're going to focus on cubic crystals + + + align:start position:0% +we're going to focus on cubic crystals +and I'm going to continue along with + + align:start position:0% +and I'm going to continue along with + + + align:start position:0% +and I'm going to continue along with +that today and in particular I want to + + align:start position:0% +that today and in particular I want to + + + align:start position:0% +that today and in particular I want to +start looking at uh notation and the + + align:start position:0% +start looking at uh notation and the + + + align:start position:0% +start looking at uh notation and the +reason I want to look at notation is I + + align:start position:0% +reason I want to look at notation is I + + + align:start position:0% +reason I want to look at notation is I +want to be able to define a point a line + + align:start position:0% +want to be able to define a point a line + + + align:start position:0% +want to be able to define a point a line +and a plane so that when we start + + align:start position:0% +and a plane so that when we start + + + align:start position:0% +and a plane so that when we start +characterizing crystals I can give you a + + align:start position:0% +characterizing crystals I can give you a + + + align:start position:0% +characterizing crystals I can give you a +mathematical notation that represents + + align:start position:0% +mathematical notation that represents + + + align:start position:0% +mathematical notation that represents +the face of the cube the body diagonal + + align:start position:0% +the face of the cube the body diagonal + + + align:start position:0% +the face of the cube the body diagonal +of the cube a line going on the body + + align:start position:0% +of the cube a line going on the body + + + align:start position:0% +of the cube a line going on the body +diagonal a line going along the edge + + align:start position:0% +diagonal a line going along the edge + + + align:start position:0% +diagonal a line going along the edge +instead of writing it in words I want to + + align:start position:0% +instead of writing it in words I want to + + + align:start position:0% +instead of writing it in words I want to +be able to do so mathematically and so + + align:start position:0% +be able to do so mathematically and so + + + align:start position:0% +be able to do so mathematically and so +for that we're going to turn to this + + align:start position:0% +for that we're going to turn to this + + + align:start position:0% +for that we're going to turn to this +handout which has the elements of + + align:start position:0% +handout which has the elements of + + + align:start position:0% +handout which has the elements of +crystallographic notation I'm going to + + align:start position:0% +crystallographic notation I'm going to + + + align:start position:0% +crystallographic notation I'm going to +quickly go through this I think last day + + align:start position:0% +quickly go through this I think last day + + + align:start position:0% +quickly go through this I think last day +we started talking about position so + + align:start position:0% +we started talking about position so + + + align:start position:0% +we started talking about position so +I've drawn a little uh sketch here this + + align:start position:0% +I've drawn a little uh sketch here this + + + align:start position:0% +I've drawn a little uh sketch here this +is the unit cell the unit cell is the + + align:start position:0% +is the unit cell the unit cell is the + + + align:start position:0% +is the unit cell the unit cell is the +cube because we're talking about a cubic + + align:start position:0% +cube because we're talking about a cubic + + + align:start position:0% +cube because we're talking about a cubic +system and this is just the lattice I + + align:start position:0% +system and this is just the lattice I + + + align:start position:0% +system and this is just the lattice I +haven't put atoms here okay so I'm just + + align:start position:0% +haven't put atoms here okay so I'm just + + + align:start position:0% +haven't put atoms here okay so I'm just +talking about lattice points in space + + align:start position:0% +talking about lattice points in space + + + align:start position:0% +talking about lattice points in space +and just to remind us a B and C are the + + align:start position:0% +and just to remind us a B and C are the + + + align:start position:0% +and just to remind us a B and C are the +unit vectors and in a cubic system a + + align:start position:0% +unit vectors and in a cubic system a + + + align:start position:0% +unit vectors and in a cubic system a +equal bals C and each of them is equal + + align:start position:0% +equal bals C and each of them is equal + + + align:start position:0% +equal bals C and each of them is equal +to a the lattice constant this is the + + align:start position:0% +to a the lattice constant this is the + + + align:start position:0% +to a the lattice constant this is the +lattice constant + + align:start position:0% +lattice constant + + + align:start position:0% +lattice constant +a and that's that's the dimension a the + + align:start position:0% +a and that's that's the dimension a the + + + align:start position:0% +a and that's that's the dimension a the +lattice constant and all angles are + + align:start position:0% +lattice constant and all angles are + + + align:start position:0% +lattice constant and all angles are +right angles so Alpha equals betaal g + + align:start position:0% +right angles so Alpha equals betaal g + + + align:start position:0% +right angles so Alpha equals betaal g +equals 90° so just to just to practice + + align:start position:0% +equals 90° so just to just to practice + + + align:start position:0% +equals 90° so just to just to practice +the origin as I've shown here the origin + + align:start position:0% +the origin as I've shown here the origin + + + align:start position:0% +the origin as I've shown here the origin +all we do is write 0 0 Z as you would in + + align:start position:0% +all we do is write 0 0 Z as you would in + + + align:start position:0% +all we do is write 0 0 Z as you would in +your math class but don't put + + align:start position:0% +your math class but don't put + + + align:start position:0% +your math class but don't put +parentheses around it because + + align:start position:0% +parentheses around it because + + + align:start position:0% +parentheses around it because +parentheses are reserved for planes + + align:start position:0% +parentheses are reserved for planes + + + align:start position:0% +parentheses are reserved for planes +we're going to use parentheses later on + + align:start position:0% +we're going to use parentheses later on + + + align:start position:0% +we're going to use parentheses later on +the crystallographers have their own + + align:start position:0% +the crystallographers have their own + + + align:start position:0% +the crystallographers have their own +notation okay so here's point a here's + + align:start position:0% +notation okay so here's point a here's + + + align:start position:0% +notation okay so here's point a here's +point a what do we see it's + + align:start position:0% +point a what do we see it's + + + align:start position:0% +point a what do we see it's +out uh it's on it's in the the YZ plane + + align:start position:0% +out uh it's on it's in the the YZ plane + + + align:start position:0% +out uh it's on it's in the the YZ plane +by the way I've chosen a um a set of + + align:start position:0% +by the way I've chosen a um a set of + + + align:start position:0% +by the way I've chosen a um a set of +coordinate axes that are in Conformity + + align:start position:0% +coordinate axes that are in Conformity + + + align:start position:0% +coordinate axes that are in Conformity +with the right hand rule I don't care + + align:start position:0% +with the right hand rule I don't care + + + align:start position:0% +with the right hand rule I don't care +which axis you choose to be X it doesn't + + align:start position:0% +which axis you choose to be X it doesn't + + + align:start position:0% +which axis you choose to be X it doesn't +matter I generally like to make Z + + align:start position:0% +matter I generally like to make Z + + + align:start position:0% +matter I generally like to make Z +vertical but I don't care as long as you + + align:start position:0% +vertical but I don't care as long as you + + + align:start position:0% +vertical but I don't care as long as you +use the right hand rule you need to + + align:start position:0% +use the right hand rule you need to + + + align:start position:0% +use the right hand rule you need to +observe the right hand rule because in + + align:start position:0% +observe the right hand rule because in + + + align:start position:0% +observe the right hand rule because in +physics you're going to find that there + + align:start position:0% +physics you're going to find that there + + + align:start position:0% +physics you're going to find that there +are certain Vector forces that are the + + align:start position:0% +are certain Vector forces that are the + + + align:start position:0% +are certain Vector forces that are the +product cross product and if you don't + + align:start position:0% +product cross product and if you don't + + + align:start position:0% +product cross product and if you don't +use the right-and rule convention you'll + + align:start position:0% +use the right-and rule convention you'll + + + align:start position:0% +use the right-and rule convention you'll +get things identically backwards so the + + align:start position:0% +get things identically backwards so the + + + align:start position:0% +get things identically backwards so the +thumb is your x axis y AIS z-axis + + align:start position:0% +thumb is your x axis y AIS z-axis + + + align:start position:0% +thumb is your x axis y AIS z-axis +however you want to do it so I've got + + align:start position:0% +however you want to do it so I've got + + + align:start position:0% +however you want to do it so I've got +the x-axis coming out of the board the y + + align:start position:0% +the x-axis coming out of the board the y + + + align:start position:0% +the x-axis coming out of the board the y +axis and the z-axis are in the plane of + + align:start position:0% +axis and the z-axis are in the plane of + + + align:start position:0% +axis and the z-axis are in the plane of +the board um so if we come here this + + align:start position:0% +the board um so if we come here this + + + align:start position:0% +the board um so if we come here this +point a is zero units out on the x axis + + align:start position:0% +point a is zero units out on the x axis + + + align:start position:0% +point a is zero units out on the x axis +it's one unit out on the y axis one unit + + align:start position:0% +it's one unit out on the y axis one unit + + + align:start position:0% +it's one unit out on the y axis one unit +up on z-axis so this would be 011 and B + + align:start position:0% +up on z-axis so this would be 011 and B + + + align:start position:0% +up on z-axis so this would be 011 and B +as I've drawn it looks like it's uh one + + align:start position:0% +as I've drawn it looks like it's uh one + + + align:start position:0% +as I've drawn it looks like it's uh one +unit out on the um x axis it's uh no + + align:start position:0% +unit out on the um x axis it's uh no + + + align:start position:0% +unit out on the um x axis it's uh no +units out on the y axis and a half a + + align:start position:0% +units out on the y axis and a half a + + + align:start position:0% +units out on the y axis and a half a +unit up on the z-axis so that's 1 z a + + align:start position:0% +unit up on the z-axis so that's 1 z a + + + align:start position:0% +unit up on the z-axis so that's 1 z a +half so that's that's about the last + + align:start position:0% +half so that's that's about the last + + + align:start position:0% +half so that's that's about the last +time I'm going to want to talk about + + align:start position:0% +time I'm going to want to talk about + + + align:start position:0% +time I'm going to want to talk about +these things it's more interesting to + + align:start position:0% +these things it's more interesting to + + + align:start position:0% +these things it's more interesting to +talk about lines so for lines I'm going + + align:start position:0% +talk about lines so for lines I'm going + + + align:start position:0% +talk about lines so for lines I'm going +to say let's just follow along the slide + + align:start position:0% +to say let's just follow along the slide + + + align:start position:0% +to say let's just follow along the slide +and the slide uh imitates what's going + + align:start position:0% +and the slide uh imitates what's going + + + align:start position:0% +and the slide uh imitates what's going +on here so let's see I've got a couple + + align:start position:0% +on here so let's see I've got a couple + + + align:start position:0% +on here so let's see I've got a couple +of them I want to try let's look at uh + + align:start position:0% +of them I want to try let's look at uh + + + align:start position:0% +of them I want to try let's look at uh +for starters OB we want to look at uh OB + + align:start position:0% +for starters OB we want to look at uh OB + + + align:start position:0% +for starters OB we want to look at uh OB +so I'm going to start at the origin and + + align:start position:0% +so I'm going to start at the origin and + + + align:start position:0% +so I'm going to start at the origin and +I'm going to come out to the point B and + + align:start position:0% +I'm going to come out to the point B and + + + align:start position:0% +I'm going to come out to the point B and +I've got a vector on this it's emanating + + align:start position:0% +I've got a vector on this it's emanating + + + align:start position:0% +I've got a vector on this it's emanating +from the origin out to B and what does + + align:start position:0% +from the origin out to B and what does + + + align:start position:0% +from the origin out to B and what does +it say to do it says Uh define a vector + + align:start position:0% +it say to do it says Uh define a vector + + + align:start position:0% +it say to do it says Uh define a vector +from origin of the point on the line + + align:start position:0% +from origin of the point on the line + + + align:start position:0% +from origin of the point on the line +choose the smallest set of integers andc + + align:start position:0% +choose the smallest set of integers andc + + + align:start position:0% +choose the smallest set of integers andc +no commas so I put the origin which + + align:start position:0% +no commas so I put the origin which + + + align:start position:0% +no commas so I put the origin which +conveniently here is the origin out to + + align:start position:0% +conveniently here is the origin out to + + + align:start position:0% +conveniently here is the origin out to +the point along that direction so the + + align:start position:0% +the point along that direction so the + + + align:start position:0% +the point along that direction so the +vector OB as written will go from there + + align:start position:0% +vector OB as written will go from there + + + align:start position:0% +vector OB as written will go from there +out to what is it goes to 1 z a half but + + align:start position:0% +out to what is it goes to 1 z a half but + + + align:start position:0% +out to what is it goes to 1 z a half but +then it says on + + align:start position:0% +then it says on + + + align:start position:0% +then it says on +uh let's see no commas and closing + + align:start position:0% +uh let's see no commas and closing + + + align:start position:0% +uh let's see no commas and closing +brackets and clear the fractions they + + align:start position:0% +brackets and clear the fractions they + + + align:start position:0% +brackets and clear the fractions they +don't like to have fractions when you're + + align:start position:0% +don't like to have fractions when you're + + + align:start position:0% +don't like to have fractions when you're +talking about lines so clear the + + align:start position:0% +talking about lines so clear the + + + align:start position:0% +talking about lines so clear the +fractions multiply through so then + + align:start position:0% +fractions multiply through so then + + + align:start position:0% +fractions multiply through so then +that'll just double it two 01 and you + + align:start position:0% +that'll just double it two 01 and you + + + align:start position:0% +that'll just double it two 01 and you +could say well what are they doing + + align:start position:0% +could say well what are they doing + + + align:start position:0% +could say well what are they doing +actually if you can imagine going out + + align:start position:0% +actually if you can imagine going out + + + align:start position:0% +actually if you can imagine going out +one more one more unit cell this line + + align:start position:0% +one more one more unit cell this line + + + align:start position:0% +one more one more unit cell this line +would actually go through the point 2011 + + align:start position:0% +would actually go through the point 2011 + + + align:start position:0% +would actually go through the point 2011 +so you're just looking at the projection + + align:start position:0% +so you're just looking at the projection + + + align:start position:0% +so you're just looking at the projection +along here you're just multiplying it + + align:start position:0% +along here you're just multiplying it + + + align:start position:0% +along here you're just multiplying it +and then it says no commas and enclosing + + align:start position:0% +and then it says no commas and enclosing + + + align:start position:0% +and then it says no commas and enclosing +brackets + + align:start position:0% +brackets + + + align:start position:0% +brackets +okay this is called a bracket these + + align:start position:0% +okay this is called a bracket these + + + align:start position:0% +okay this is called a bracket these +staple like things are called + + align:start position:0% +staple like things are called + + + align:start position:0% +staple like things are called +brackets so that's a direction the + + align:start position:0% +brackets so that's a direction the + + + align:start position:0% +brackets so that's a direction the +direction o let's do the uh let's see + + align:start position:0% +direction o let's do the uh let's see + + + align:start position:0% +direction o let's do the uh let's see +what's the other one we're going to do + + align:start position:0% +what's the other one we're going to do + + + align:start position:0% +what's the other one we're going to do +what is it AO + + align:start position:0% +what is it AO + + + align:start position:0% +what is it AO +AO all right so it says you have to move + + align:start position:0% +AO all right so it says you have to move + + + align:start position:0% +AO all right so it says you have to move +the origin to the base of the vector so + + align:start position:0% +the origin to the base of the vector so + + + align:start position:0% +the origin to the base of the vector so +if I want to do AO I have to I have to + + align:start position:0% +if I want to do AO I have to I have to + + + align:start position:0% +if I want to do AO I have to I have to +put the origin up here at the tail of + + align:start position:0% +put the origin up here at the tail of + + + align:start position:0% +put the origin up here at the tail of +the vector so if this is the origin I'm + + align:start position:0% +the vector so if this is the origin I'm + + + align:start position:0% +the vector so if this is the origin I'm +moving actually what I'm not moving + + align:start position:0% +moving actually what I'm not moving + + + align:start position:0% +moving actually what I'm not moving +anywhere in the x- axis but I'm moving + + align:start position:0% +anywhere in the x- axis but I'm moving + + + align:start position:0% +anywhere in the x- axis but I'm moving +minus one in the Y AIS and minus one in + + align:start position:0% +minus one in the Y AIS and minus one in + + + align:start position:0% +minus one in the Y AIS and minus one in +the z-axis in order to get this + + align:start position:0% +the z-axis in order to get this + + + align:start position:0% +the z-axis in order to get this +direction so I'm really going zero in + + align:start position:0% +direction so I'm really going zero in + + + align:start position:0% +direction so I'm really going zero in +the X I'm going minus one in the Y and + + align:start position:0% +the X I'm going minus one in the Y and + + + align:start position:0% +the X I'm going minus one in the Y and +minus one in the Z and you can see since + + align:start position:0% +minus one in the Z and you can see since + + + align:start position:0% +minus one in the Z and you can see since +we don't use commas putting minus signs + + align:start position:0% +we don't use commas putting minus signs + + + align:start position:0% +we don't use commas putting minus signs +would look cumbersome so in + + align:start position:0% +would look cumbersome so in + + + align:start position:0% +would look cumbersome so in +crystallographic notation the minus sign + + align:start position:0% +crystallographic notation the minus sign + + + align:start position:0% +crystallographic notation the minus sign +is represented as a macron a macron is a + + align:start position:0% +is represented as a macron a macron is a + + + align:start position:0% +is represented as a macron a macron is a +line over so this is z one bar one bar + + align:start position:0% +line over so this is z one bar one bar + + + align:start position:0% +line over so this is z one bar one bar +that's equal to minus one but in Crystal + + align:start position:0% +that's equal to minus one but in Crystal + + + align:start position:0% +that's equal to minus one but in Crystal +crystallographers use the term one bar + + align:start position:0% +crystallographers use the term one bar + + + align:start position:0% +crystallographers use the term one bar +so this is o one bar one bar for this + + align:start position:0% +so this is o one bar one bar for this + + + align:start position:0% +so this is o one bar one bar for this +line uh a down to origin so that's + + align:start position:0% +line uh a down to origin so that's + + + align:start position:0% +line uh a down to origin so that's +that's how that's done and then it says + + align:start position:0% +that's how that's done and then it says + + + align:start position:0% +that's how that's done and then it says +uh let's see we can denote an entire + + align:start position:0% +uh let's see we can denote an entire + + + align:start position:0% +uh let's see we can denote an entire +family of directions by carrots so let's + + align:start position:0% +family of directions by carrots so let's + + + align:start position:0% +family of directions by carrots so let's +do that if I want to suppose I wanted to + + align:start position:0% +do that if I want to suppose I wanted to + + + align:start position:0% +do that if I want to suppose I wanted to +say um what have I got up there all of + + align:start position:0% +say um what have I got up there all of + + + align:start position:0% +say um what have I got up there all of +the body diagonals well how would I get + + align:start position:0% +the body diagonals well how would I get + + + align:start position:0% +the body diagonals well how would I get +a body diagonal + + align:start position:0% +a body diagonal + + + align:start position:0% +a body diagonal +a body + + align:start position:0% + + + + align:start position:0% + +diagonal if this is the origin and I + + align:start position:0% +diagonal if this is the origin and I + + + align:start position:0% +diagonal if this is the origin and I +want to go up the body diagonal it would + + align:start position:0% +want to go up the body diagonal it would + + + align:start position:0% +want to go up the body diagonal it would +be out one unit out one unit out one + + align:start position:0% +be out one unit out one unit out one + + + align:start position:0% +be out one unit out one unit out one +unit so it would be 11 one one would be + + align:start position:0% +unit so it would be 11 one one would be + + + align:start position:0% +unit so it would be 11 one one would be +a body diagonal all right but suppose I + + align:start position:0% +a body diagonal all right but suppose I + + + align:start position:0% +a body diagonal all right but suppose I +want to say all body diagonals that's + + align:start position:0% +want to say all body diagonals that's + + + align:start position:0% +want to say all body diagonals that's +111 this direction one1 that direction I + + align:start position:0% +111 this direction one1 that direction I + + + align:start position:0% +111 this direction one1 that direction I +want to get this body diagonal I want to + + align:start position:0% +want to get this body diagonal I want to + + + align:start position:0% +want to get this body diagonal I want to +get that body diagonal how do I do that + + align:start position:0% +get that body diagonal how do I do that + + + align:start position:0% +get that body diagonal how do I do that +I can do that by putting carrots these + + align:start position:0% +I can do that by putting carrots these + + + align:start position:0% +I can do that by putting carrots these +are called carrots those of you who have + + align:start position:0% +are called carrots those of you who have + + + align:start position:0% +are called carrots those of you who have +done some editing and proof reading know + + align:start position:0% +done some editing and proof reading know + + + align:start position:0% +done some editing and proof reading know +these terms okay so carrots so this is + + align:start position:0% +these terms okay so carrots so this is + + + align:start position:0% +these terms okay so carrots so this is +all body + + align:start position:0% +all body + + + align:start position:0% +all body +diagonals this is all body + + align:start position:0% + + + + align:start position:0% + +diagonals we could do a few others while + + align:start position:0% +diagonals we could do a few others while + + + align:start position:0% +diagonals we could do a few others while +we're at it suppose I wanted to do uh + + align:start position:0% +we're at it suppose I wanted to do uh + + + align:start position:0% +we're at it suppose I wanted to do uh +all of the face + + align:start position:0% +all of the face + + + align:start position:0% +all of the face +diagonals all of the face diagonals like + + align:start position:0% +diagonals all of the face diagonals like + + + align:start position:0% +diagonals all of the face diagonals like +this like this and then over here like + + align:start position:0% +this like this and then over here like + + + align:start position:0% +this like this and then over here like +this like this well what's a face + + align:start position:0% +this like this well what's a face + + + align:start position:0% +this like this well what's a face +diagonal 0 1 0 1 1 right so all the face + + align:start position:0% +diagonal 0 1 0 1 1 right so all the face + + + align:start position:0% +diagonal 0 1 0 1 1 right so all the face +diagonals would be okay all face + + align:start position:0% + + + + align:start position:0% + +diagonals um what about all Cube edges + + align:start position:0% +diagonals um what about all Cube edges + + + align:start position:0% +diagonals um what about all Cube edges +what's a cube Edge Cube Edge could be + + align:start position:0% +what's a cube Edge Cube Edge could be + + + align:start position:0% +what's a cube Edge Cube Edge could be +this one 0 01 so this would be all + + align:start position:0% +this one 0 01 so this would be all + + + align:start position:0% +this one 0 01 so this would be all +Cube + + align:start position:0% +Cube + + + align:start position:0% +Cube +edges so what does it mean it means + + align:start position:0% +edges so what does it mean it means + + + align:start position:0% +edges so what does it mean it means +write this out in full so that's O + + align:start position:0% +write this out in full so that's O + + + align:start position:0% +write this out in full so that's O +pardon me + + align:start position:0% +pardon me + + + align:start position:0% +pardon me +o1 okay o1 bar + + align:start position:0% +o1 okay o1 bar + + + align:start position:0% +o1 okay o1 bar +R + + align:start position:0% +R + + + align:start position:0% +R +o10 see I'm using o for zero I'm I'm + + align:start position:0% +o10 see I'm using o for zero I'm I'm + + + align:start position:0% +o10 see I'm using o for zero I'm I'm +cluing you into crystallographers talk + + align:start position:0% +cluing you into crystallographers talk + + + align:start position:0% +cluing you into crystallographers talk +that's how they talk o in one bar so + + align:start position:0% +that's how they talk o in one bar so + + + align:start position:0% +that's how they talk o in one bar so +you're going to be really hip if you end + + align:start position:0% +you're going to be really hip if you end + + + align:start position:0% +you're going to be really hip if you end +up in an elevator with a bunch of + + align:start position:0% +up in an elevator with a bunch of + + + align:start position:0% +up in an elevator with a bunch of +crystallographers okay and there's two + + align:start position:0% +crystallographers okay and there's two + + + align:start position:0% +crystallographers okay and there's two +others here + + align:start position:0% +others here + + + align:start position:0% +others here +10 and one bar + + align:start position:0% +10 and one bar + + + align:start position:0% +10 and one bar +o well how many faces are there six how + + align:start position:0% +o well how many faces are there six how + + + align:start position:0% +o well how many faces are there six how +many face edges six and look just going + + align:start position:0% +many face edges six and look just going + + + align:start position:0% +many face edges six and look just going +through the permutations and + + align:start position:0% +through the permutations and + + + align:start position:0% +through the permutations and +combinations gives you exactly the + + align:start position:0% +combinations gives you exactly the + + + align:start position:0% +combinations gives you exactly the +number that you should have this is + + align:start position:0% +number that you should have this is + + + align:start position:0% +number that you should have this is +mathematics imitating reality that's + + align:start position:0% +mathematics imitating reality that's + + + align:start position:0% +mathematics imitating reality that's +good that's good and likewise here if + + align:start position:0% +good that's good and likewise here if + + + align:start position:0% +good that's good and likewise here if +you go through all the permutation + + align:start position:0% +you go through all the permutation + + + align:start position:0% +you go through all the permutation +combinations of 01 and one bar you'll + + align:start position:0% +combinations of 01 and one bar you'll + + + align:start position:0% +combinations of 01 and one bar you'll +end up with all of the possibilities for + + align:start position:0% +end up with all of the possibilities for + + + align:start position:0% +end up with all of the possibilities for +face diagonals all the possibility for + + align:start position:0% +face diagonals all the possibility for + + + align:start position:0% +face diagonals all the possibility for +body diagonals I think I've got a a + + align:start position:0% +body diagonals I think I've got a a + + + align:start position:0% +body diagonals I think I've got a a +cartoon here that shows there it is it + + align:start position:0% +cartoon here that shows there it is it + + + align:start position:0% +cartoon here that shows there it is it +shows all of the different uh diagonals + + align:start position:0% +shows all of the different uh diagonals + + + align:start position:0% +shows all of the different uh diagonals +that are possible when you mix one and + + align:start position:0% +that are possible when you mix one and + + + align:start position:0% +that are possible when you mix one and +one are okay that's good so that's so + + align:start position:0% +one are okay that's good so that's so + + + align:start position:0% +one are okay that's good so that's so +far so good that's pretty simple now + + align:start position:0% +far so good that's pretty simple now + + + align:start position:0% +far so good that's pretty simple now +let's look at planes let's look at + + align:start position:0% +let's look at planes let's look at + + + align:start position:0% +let's look at planes let's look at +planes for planes we use something + + align:start position:0% +planes for planes we use something + + + align:start position:0% +planes for planes we use something +called the Miller + + align:start position:0% +called the Miller + + + align:start position:0% +called the Miller +indices Miller indices for describing + + align:start position:0% +indices Miller indices for describing + + + align:start position:0% +indices Miller indices for describing +planes and they're named after the uh + + align:start position:0% +planes and they're named after the uh + + + align:start position:0% +planes and they're named after the uh +British minology + + align:start position:0% +British minology + + + align:start position:0% +British minology +williiam hallow Miller who back in the + + align:start position:0% +williiam hallow Miller who back in the + + + align:start position:0% +williiam hallow Miller who back in the +1830s gave us this uh means of + + align:start position:0% +1830s gave us this uh means of + + + align:start position:0% +1830s gave us this uh means of +describing a plane and I think I would + + align:start position:0% +describing a plane and I think I would + + + align:start position:0% +describing a plane and I think I would +rather than write it down just just + + align:start position:0% +rather than write it down just just + + + align:start position:0% +rather than write it down just just +follow along here because you got the + + align:start position:0% +follow along here because you got the + + + align:start position:0% +follow along here because you got the +notes in front of you you know from your + + align:start position:0% +notes in front of you you know from your + + + align:start position:0% +notes in front of you you know from your +math that the uh equation of a plane is + + align:start position:0% +math that the uh equation of a plane is + + + align:start position:0% +math that the uh equation of a plane is +X over a + y over B plus Z over Cal 1 + + align:start position:0% +X over a + y over B plus Z over Cal 1 + + + align:start position:0% +X over a + y over B plus Z over Cal 1 +and a B and C are the intercepts with + + align:start position:0% +and a B and C are the intercepts with + + + align:start position:0% +and a B and C are the intercepts with +the X Y and Z axis respectively so what + + align:start position:0% +the X Y and Z axis respectively so what + + + align:start position:0% +the X Y and Z axis respectively so what +what um what Miller did is he said let's + + align:start position:0% +what um what Miller did is he said let's + + + align:start position:0% +what um what Miller did is he said let's +let H be 1 over a k be one over B and + + align:start position:0% +let H be 1 over a k be one over B and + + + align:start position:0% +let H be 1 over a k be one over B and +Lal 1 / C so this becomes the equation + + align:start position:0% +Lal 1 / C so this becomes the equation + + + align:start position:0% +Lal 1 / C so this becomes the equation +of the plane HX + KY + LZ = one and now + + align:start position:0% +of the plane HX + KY + LZ = one and now + + + align:start position:0% +of the plane HX + KY + LZ = one and now +what you do is you take the h k and l + + align:start position:0% +what you do is you take the h k and l + + + align:start position:0% +what you do is you take the h k and l +and enclose those in parentheses so in + + align:start position:0% +and enclose those in parentheses so in + + + align:start position:0% +and enclose those in parentheses so in +other words he's taking the plane index + + align:start position:0% +other words he's taking the plane index + + + align:start position:0% +other words he's taking the plane index +to be the reciprocals of the intercepts + + align:start position:0% +to be the reciprocals of the intercepts + + + align:start position:0% +to be the reciprocals of the intercepts +with the three axes and you'll see why + + align:start position:0% +with the three axes and you'll see why + + + align:start position:0% +with the three axes and you'll see why +in a second you'll see why in a second + + align:start position:0% +in a second you'll see why in a second + + + align:start position:0% +in a second you'll see why in a second +why do it that way well because every + + align:start position:0% +why do it that way well because every + + + align:start position:0% +why do it that way well because every +once in a while something like this + + align:start position:0% +once in a while something like this + + + align:start position:0% +once in a while something like this +happens so here's a simple one just to + + align:start position:0% +happens so here's a simple one just to + + + align:start position:0% +happens so here's a simple one just to +get our feet wet so here A B and C are + + align:start position:0% +get our feet wet so here A B and C are + + + align:start position:0% +get our feet wet so here A B and C are +the unit vectors so this is the x axis + + align:start position:0% +the unit vectors so this is the x axis + + + align:start position:0% +the unit vectors so this is the x axis +in the same convention I've chosen X is + + align:start position:0% +in the same convention I've chosen X is + + + align:start position:0% +in the same convention I've chosen X is +coming out of the plane of the slide Y + + align:start position:0% +coming out of the plane of the slide Y + + + align:start position:0% +coming out of the plane of the slide Y +is moving to the right and Z is moving + + align:start position:0% +is moving to the right and Z is moving + + + align:start position:0% +is moving to the right and Z is moving +up okay so here's a plane that's shaded + + align:start position:0% +up okay so here's a plane that's shaded + + + align:start position:0% +up okay so here's a plane that's shaded +in and what do you see it cuts the x + + align:start position:0% +in and what do you see it cuts the x + + + align:start position:0% +in and what do you see it cuts the x +axis at xal plus a half it cuts the Y + + align:start position:0% +axis at xal plus a half it cuts the Y + + + align:start position:0% +axis at xal plus a half it cuts the Y +AIS at yal +1 and it never cuts the Z + + align:start position:0% +AIS at yal +1 and it never cuts the Z + + + align:start position:0% +AIS at yal +1 and it never cuts the Z +axis it's parallel to the Z axis so + + align:start position:0% +axis it's parallel to the Z axis so + + + align:start position:0% +axis it's parallel to the Z axis so +mathematically we would say the Z + + align:start position:0% +mathematically we would say the Z + + + align:start position:0% +mathematically we would say the Z +intercept is infinity and who wants to + + align:start position:0% +intercept is infinity and who wants to + + + align:start position:0% +intercept is infinity and who wants to +have Infinity so now you see the wisdom + + align:start position:0% +have Infinity so now you see the wisdom + + + align:start position:0% +have Infinity so now you see the wisdom +of of Miller Miller said let's describe + + align:start position:0% +of of Miller Miller said let's describe + + + align:start position:0% +of of Miller Miller said let's describe +this in terms of the reciprocals so + + align:start position:0% +this in terms of the reciprocals so + + + align:start position:0% +this in terms of the reciprocals so +what's the reciprocal of a half it's two + + align:start position:0% +what's the reciprocal of a half it's two + + + align:start position:0% +what's the reciprocal of a half it's two +what's the reciprocal of one it's one + + align:start position:0% +what's the reciprocal of one it's one + + + align:start position:0% +what's the reciprocal of one it's one +and what's the reciprocal of infinity + + align:start position:0% +and what's the reciprocal of infinity + + + align:start position:0% +and what's the reciprocal of infinity +zero so we can describe this plane as + + align:start position:0% +zero so we can describe this plane as + + + align:start position:0% +zero so we can describe this plane as +the 2 one0 + + align:start position:0% +the 2 one0 + + + align:start position:0% +the 2 one0 +plane whenever you see a zero whatever + + align:start position:0% +plane whenever you see a zero whatever + + + align:start position:0% +plane whenever you see a zero whatever +place the zero lies that means that + + align:start position:0% +place the zero lies that means that + + + align:start position:0% +place the zero lies that means that +plane is parallel to that axis so right + + align:start position:0% +plane is parallel to that axis so right + + + align:start position:0% +plane is parallel to that axis so right +away I can say that's a plane that's + + align:start position:0% +away I can say that's a plane that's + + + align:start position:0% +away I can say that's a plane that's +parallel to the z-axis it doesn't cross + + align:start position:0% +parallel to the z-axis it doesn't cross + + + align:start position:0% +parallel to the z-axis it doesn't cross +the z- axis so there it is so there's + + align:start position:0% +the z- axis so there it is so there's + + + align:start position:0% +the z- axis so there it is so there's +the uh formula you take the reciprocal + + align:start position:0% +the uh formula you take the reciprocal + + + align:start position:0% +the uh formula you take the reciprocal +of the intercepts put them side by side + + align:start position:0% +of the intercepts put them side by side + + + align:start position:0% +of the intercepts put them side by side +no commas and this is why we Sav the + + align:start position:0% +no commas and this is why we Sav the + + + align:start position:0% +no commas and this is why we Sav the +parentheses and that's why we don't put + + align:start position:0% +parentheses and that's why we don't put + + + align:start position:0% +parentheses and that's why we don't put +our uh position in parenthesis because + + align:start position:0% +our uh position in parenthesis because + + + align:start position:0% +our uh position in parenthesis because +we're saving parentheses for the plane + + align:start position:0% +we're saving parentheses for the plane + + + align:start position:0% +we're saving parentheses for the plane +oh let's do a few more this is W it's a + + align:start position:0% +oh let's do a few more this is W it's a + + + align:start position:0% +oh let's do a few more this is W it's a +lot of fun on a Monday see you're + + align:start position:0% +lot of fun on a Monday see you're + + + align:start position:0% +lot of fun on a Monday see you're +excited to be back in class and man + + align:start position:0% +excited to be back in class and man + + + align:start position:0% +excited to be back in class and man +there's a cool thing that happens when + + align:start position:0% +there's a cool thing that happens when + + + align:start position:0% +there's a cool thing that happens when +you use Miller indices you see what I + + align:start position:0% +you use Miller indices you see what I + + + align:start position:0% +you use Miller indices you see what I +just did I just drew a Direction and + + align:start position:0% +just did I just drew a Direction and + + + align:start position:0% +just did I just drew a Direction and +that direction is the 210 Direction and + + align:start position:0% +that direction is the 210 Direction and + + + align:start position:0% +that direction is the 210 Direction and +what do you notice about the position of + + align:start position:0% +what do you notice about the position of + + + align:start position:0% +what do you notice about the position of +210 versus the 210 plane when you write + + align:start position:0% +210 versus the 210 plane when you write + + + align:start position:0% +210 versus the 210 plane when you write +directions according to this formula and + + align:start position:0% +directions according to this formula and + + + align:start position:0% +directions according to this formula and +planes according to Miller indices the + + align:start position:0% +planes according to Miller indices the + + + align:start position:0% +planes according to Miller indices the +210 direction is perpendicular to the + + align:start position:0% +210 direction is perpendicular to the + + + align:start position:0% +210 direction is perpendicular to the + + align:start position:0% + + + align:start position:0% +plane 210 direction is perpendicular to + + align:start position:0% +plane 210 direction is perpendicular to + + + align:start position:0% +plane 210 direction is perpendicular to +the 210 plane let's do another one oh + + align:start position:0% +the 210 plane let's do another one oh + + + align:start position:0% +the 210 plane let's do another one oh +this is a good one this is uh this is a + + align:start position:0% +this is a good one this is uh this is a + + + align:start position:0% +this is a good one this is uh this is a +plane + + align:start position:0% +plane + + + align:start position:0% +plane +that cuts the Y AIS at y equal 1 it's + + align:start position:0% +that cuts the Y AIS at y equal 1 it's + + + align:start position:0% +that cuts the Y AIS at y equal 1 it's +parallel to the x-axis parallel to the + + align:start position:0% +parallel to the x-axis parallel to the + + + align:start position:0% +parallel to the x-axis parallel to the +z-axis never cuts the x or the + + align:start position:0% +z-axis never cuts the x or the + + + align:start position:0% +z-axis never cuts the x or the +z-axis so that's an 010 plane I mean you + + align:start position:0% +z-axis so that's an 010 plane I mean you + + + align:start position:0% +z-axis so that's an 010 plane I mean you +can do that in your head right so that's + + align:start position:0% +can do that in your head right so that's + + + align:start position:0% +can do that in your head right so that's +an 01 plane that's an o10 plane and so + + align:start position:0% +an 01 plane that's an o10 plane and so + + + align:start position:0% +an 01 plane that's an o10 plane and so +on and so forth here's an o2o plane why + + align:start position:0% +on and so forth here's an o2o plane why + + + align:start position:0% +on and so forth here's an o2o plane why +well because it cuts the y axis at y + + align:start position:0% +well because it cuts the y axis at y + + + align:start position:0% +well because it cuts the y axis at y +equals a half and take the reciprocal is + + align:start position:0% +equals a half and take the reciprocal is + + + align:start position:0% +equals a half and take the reciprocal is +two so o20 + + align:start position:0% +two so o20 + + + align:start position:0% +two so o20 +o2o and let's try again well there's 010 + + align:start position:0% +o2o and let's try again well there's 010 + + + align:start position:0% +o2o and let's try again well there's 010 +Direction and what do you know the o10 + + align:start position:0% +Direction and what do you know the o10 + + + align:start position:0% +Direction and what do you know the o10 +direction is normal to the o10 plane and + + align:start position:0% +direction is normal to the o10 plane and + + + align:start position:0% +direction is normal to the o10 plane and +o2o direction is normal to the o2o plane + + align:start position:0% +o2o direction is normal to the o2o plane + + + align:start position:0% +o2o direction is normal to the o2o plane +what do you know about the o10 direction + + align:start position:0% +what do you know about the o10 direction + + + align:start position:0% +what do you know about the o10 direction +the o2o direction they're the same + + align:start position:0% +the o2o direction they're the same + + + align:start position:0% +the o2o direction they're the same +direction o anything o is going to be + + align:start position:0% +direction o anything o is going to be + + + align:start position:0% +direction o anything o is going to be +along the y + + align:start position:0% + + + + align:start position:0% + +axis that's an o2o plane I could shift + + align:start position:0% +axis that's an o2o plane I could shift + + + align:start position:0% +axis that's an o2o plane I could shift +the origin to here couldn't I so then + + align:start position:0% +the origin to here couldn't I so then + + + align:start position:0% +the origin to here couldn't I so then +that would be an O2 plane and that would + + align:start position:0% +that would be an O2 plane and that would + + + align:start position:0% +that would be an O2 plane and that would +be an O2 + + align:start position:0% + + + + align:start position:0% + +plane well here's some more + + align:start position:0% +plane well here's some more + + + align:start position:0% +plane well here's some more +111 well look at this plane here it cuts + + align:start position:0% +111 well look at this plane here it cuts + + + align:start position:0% +111 well look at this plane here it cuts +the x axis at x equals 1 the y axis at y + + align:start position:0% +the x axis at x equals 1 the y axis at y + + + align:start position:0% +the x axis at x equals 1 the y axis at y +equals 1 the z-axis at Z equals 1 so + + align:start position:0% +equals 1 the z-axis at Z equals 1 so + + + align:start position:0% +equals 1 the z-axis at Z equals 1 so +shade that in that's the 111 plane but + + align:start position:0% +shade that in that's the 111 plane but + + + align:start position:0% +shade that in that's the 111 plane but +that's also a 111 plane we can keep + + align:start position:0% +that's also a 111 plane we can keep + + + align:start position:0% +that's also a 111 plane we can keep +Shifting the origin I don't know where + + align:start position:0% +Shifting the origin I don't know where + + + align:start position:0% +Shifting the origin I don't know where +the origin of the universe is so I can + + align:start position:0% +the origin of the universe is so I can + + + align:start position:0% +the origin of the universe is so I can +move this anywhere along + + align:start position:0% +move this anywhere along + + + align:start position:0% +move this anywhere along +now here's one here's backwards see this + + align:start position:0% +now here's one here's backwards see this + + + align:start position:0% +now here's one here's backwards see this +now is one one one bar because if I put + + align:start position:0% +now is one one one bar because if I put + + + align:start position:0% +now is one one one bar because if I put +the uh if I put the origin here I'm + + align:start position:0% +the uh if I put the origin here I'm + + + align:start position:0% +the uh if I put the origin here I'm +cutting the x- axis at + one I'm cutting + + align:start position:0% +cutting the x- axis at + one I'm cutting + + + align:start position:0% +cutting the x- axis at + one I'm cutting +the Y AIS at + one but I've got a + + align:start position:0% +the Y AIS at + one but I've got a + + + align:start position:0% +the Y AIS at + one but I've got a +negative tilt to this plane so the + + align:start position:0% +negative tilt to this plane so the + + + align:start position:0% +negative tilt to this plane so the +z-axis is being cut at minus one so + + align:start position:0% +z-axis is being cut at minus one so + + + align:start position:0% +z-axis is being cut at minus one so +again we try to use the minus sign uh + + align:start position:0% +again we try to use the minus sign uh + + + align:start position:0% +again we try to use the minus sign uh +avoid the minus sign rather and instead + + align:start position:0% +avoid the minus sign rather and instead + + + align:start position:0% +avoid the minus sign rather and instead +we put the macron over the number and in + + align:start position:0% +we put the macron over the number and in + + + align:start position:0% +we put the macron over the number and in +that way we give the uh minus indication + + align:start position:0% +that way we give the uh minus indication + + + align:start position:0% +that way we give the uh minus indication +on a number no par no commas in + + align:start position:0% +on a number no par no commas in + + + align:start position:0% +on a number no par no commas in +parentheses now let's do the test here's + + align:start position:0% +parentheses now let's do the test here's + + + align:start position:0% +parentheses now let's do the test here's +the 111 Direction and sure enough the + + align:start position:0% +the 111 Direction and sure enough the + + + align:start position:0% +the 111 Direction and sure enough the +111 Direction cuts the 111 plane + + align:start position:0% +111 Direction cuts the 111 plane + + + align:start position:0% +111 Direction cuts the 111 plane +normally let's try over here there's the + + align:start position:0% +normally let's try over here there's the + + + align:start position:0% +normally let's try over here there's the +111 bar Direction Boom cuts through the + + align:start position:0% +111 bar Direction Boom cuts through the + + + align:start position:0% +111 bar Direction Boom cuts through the +111 bar plane + + align:start position:0% +111 bar plane + + + align:start position:0% +111 bar plane +normally it's fantastic fantastic and we + + align:start position:0% +normally it's fantastic fantastic and we + + + align:start position:0% +normally it's fantastic fantastic and we +can do families we can do families of + + align:start position:0% +can do families we can do families of + + + align:start position:0% +can do families we can do families of +planes as well so let's look at families + + align:start position:0% +planes as well so let's look at families + + + align:start position:0% +planes as well so let's look at families +of planes what kind of families could we + + align:start position:0% +of planes what kind of families could we + + + align:start position:0% +of planes what kind of families could we +we could come up with if we want to do + + align:start position:0% +we could come up with if we want to do + + + align:start position:0% +we could come up with if we want to do +families families of planes with brace + + align:start position:0% +families families of planes with brace + + + align:start position:0% +families families of planes with brace +brackets + + align:start position:0% +brackets + + + align:start position:0% +brackets +right families of + + align:start position:0% + + + + align:start position:0% + +planes + + align:start position:0% +planes + + + align:start position:0% +planes +use + + align:start position:0% + + + + align:start position:0% + +braces so if I want to say all Cube + + align:start position:0% +braces so if I want to say all Cube + + + align:start position:0% +braces so if I want to say all Cube +faces all Cube faces that would be + + align:start position:0% +faces all Cube faces that would be + + + align:start position:0% +faces all Cube faces that would be +o1 because 010 we saw was the was + + align:start position:0% +o1 because 010 we saw was the was + + + align:start position:0% +o1 because 010 we saw was the was +parallel to the cuts the y axis parallel + + align:start position:0% +parallel to the cuts the y axis parallel + + + align:start position:0% +parallel to the cuts the y axis parallel +to the XZ plane so that's going to tell + + align:start position:0% +to the XZ plane so that's going to tell + + + align:start position:0% +to the XZ plane so that's going to tell +you to roll over 0 01 and one bar in + + align:start position:0% +you to roll over 0 01 and one bar in + + + align:start position:0% +you to roll over 0 01 and one bar in +this manner only instead of brackets + + align:start position:0% +this manner only instead of brackets + + + align:start position:0% +this manner only instead of brackets +you've got braces how many faces on a + + align:start position:0% +you've got braces how many faces on a + + + align:start position:0% +you've got braces how many faces on a +cube there's six how many combinations + + align:start position:0% +cube there's six how many combinations + + + align:start position:0% +cube there's six how many combinations +of zero one and one bar are there six so + + align:start position:0% +of zero one and one bar are there six so + + + align:start position:0% +of zero one and one bar are there six so +there you go and by the way one other + + align:start position:0% +there you go and by the way one other + + + align:start position:0% +there you go and by the way one other +thing if you want to be hip with the + + align:start position:0% +thing if you want to be hip with the + + + align:start position:0% +thing if you want to be hip with the +crystallographers this is one way of + + align:start position:0% +crystallographers this is one way of + + + align:start position:0% +crystallographers this is one way of +writing it another way of writing it is + + align:start position:0% +writing it another way of writing it is + + + align:start position:0% +writing it another way of writing it is +10 10 is equivalent to 1 but + + align:start position:0% +10 10 is equivalent to 1 but + + + align:start position:0% +10 10 is equivalent to 1 but +crystallographers like to put things in + + align:start position:0% +crystallographers like to put things in + + + align:start position:0% +crystallographers like to put things in +ascending order so the crystallographer + + align:start position:0% +ascending order so the crystallographer + + + align:start position:0% +ascending order so the crystallographer +would never write 10 crystallographer + + align:start position:0% +would never write 10 crystallographer + + + align:start position:0% +would never write 10 crystallographer +write o1 so that's that's cool Factor + + align:start position:0% +write o1 so that's that's cool Factor + + + align:start position:0% +write o1 so that's that's cool Factor +there if you want to get you you never + + align:start position:0% +there if you want to get you you never + + + align:start position:0% +there if you want to get you you never +know when you're going to meet a + + align:start position:0% +know when you're going to meet a + + + align:start position:0% +know when you're going to meet a +crystallographer on an elevator it could + + align:start position:0% +crystallographer on an elevator it could + + + align:start position:0% +crystallographer on an elevator it could +come in it could be the ice breaker + + align:start position:0% +come in it could be the ice breaker + + + align:start position:0% +come in it could be the ice breaker +because they might be shy you know okay + + align:start position:0% +because they might be shy you know okay + + + align:start position:0% +because they might be shy you know okay +and the last thing the last thing I want + + align:start position:0% +and the last thing the last thing I want + + + align:start position:0% +and the last thing the last thing I want +to do is talk about the distance + + align:start position:0% +to do is talk about the distance + + + align:start position:0% +to do is talk about the distance +calculation another virtue of using + + align:start position:0% +calculation another virtue of using + + + align:start position:0% +calculation another virtue of using +Miller indices I want to put this up + + align:start position:0% +Miller indices I want to put this up + + + align:start position:0% +Miller indices I want to put this up +here because it's it's on the handout + + align:start position:0% +here because it's it's on the handout + + + align:start position:0% +here because it's it's on the handout +but I want to make sure that it gets on + + align:start position:0% +but I want to make sure that it gets on + + + align:start position:0% +but I want to make sure that it gets on +the board the hkl plane is perpendicular + + align:start position:0% +the board the hkl plane is perpendicular + + + align:start position:0% +the board the hkl plane is perpendicular +to the + + align:start position:0% +to the + + + align:start position:0% +to the +hkl direction when we use such a + + align:start position:0% +hkl direction when we use such a + + + align:start position:0% +hkl direction when we use such a +notation and then I want to show let's + + align:start position:0% +notation and then I want to show let's + + + align:start position:0% +notation and then I want to show let's +go back to the previous slide uh go back + + align:start position:0% +go back to the previous slide uh go back + + + align:start position:0% +go back to the previous slide uh go back +two of them because it's easier to see + + align:start position:0% +two of them because it's easier to see + + + align:start position:0% +two of them because it's easier to see +here I want to calculate the distance + + align:start position:0% +here I want to calculate the distance + + + align:start position:0% +here I want to calculate the distance +between adjacent planes of the same + + align:start position:0% +between adjacent planes of the same + + + align:start position:0% +between adjacent planes of the same +index so we can calculate the distance + + align:start position:0% + + + + align:start position:0% + +the distance between adjacent + + align:start position:0% + + + + align:start position:0% + +planes between adjacent planes of the + + align:start position:0% +planes between adjacent planes of the + + + align:start position:0% +planes between adjacent planes of the +same + + align:start position:0% + + + + align:start position:0% + +index + + align:start position:0% +index + + + align:start position:0% +index +so what's the distance between two + + align:start position:0% +so what's the distance between two + + + align:start position:0% +so what's the distance between two +adjacent planes of some value hkl and + + align:start position:0% +adjacent planes of some value hkl and + + + align:start position:0% +adjacent planes of some value hkl and +that's given by the the + + align:start position:0% +that's given by the the + + + align:start position:0% +that's given by the the +following formula which again is a + + align:start position:0% +following formula which again is a + + + align:start position:0% +following formula which again is a +testimony to uh to Miller the the + + align:start position:0% +testimony to uh to Miller the the + + + align:start position:0% +testimony to uh to Miller the the +distance and I'm going to subscript it + + align:start position:0% +distance and I'm going to subscript it + + + align:start position:0% +distance and I'm going to subscript it +hkl because they're all the same index + + align:start position:0% +hkl because they're all the same index + + + align:start position:0% +hkl because they're all the same index +is given + + align:start position:0% +is given + + + align:start position:0% +is given +by a which is the lce constant divided + + align:start position:0% +by a which is the lce constant divided + + + align:start position:0% +by a which is the lce constant divided +by the square root of h^2 + K2 + + + align:start position:0% +by the square root of h^2 + K2 + + + + align:start position:0% +by the square root of h^2 + K2 + +L2 where a is the lattice + + align:start position:0% + + + + align:start position:0% + +constant okay so let's test it if hkl is + + align:start position:0% +constant okay so let's test it if hkl is + + + align:start position:0% +constant okay so let's test it if hkl is +010 well trivially that separation + + align:start position:0% +010 well trivially that separation + + + align:start position:0% +010 well trivially that separation +should be a the lattice constant and I + + align:start position:0% +should be a the lattice constant and I + + + align:start position:0% +should be a the lattice constant and I +think you can see that quite nicely up + + align:start position:0% +think you can see that quite nicely up + + + align:start position:0% +think you can see that quite nicely up +on the the screen here it's one lattice + + align:start position:0% +on the the screen here it's one lattice + + + align:start position:0% +on the the screen here it's one lattice +constant between successive o10 planes + + align:start position:0% +constant between successive o10 planes + + + align:start position:0% +constant between successive o10 planes +let's try it with o20 well it's going to + + align:start position:0% +let's try it with o20 well it's going to + + + align:start position:0% +let's try it with o20 well it's going to +be the square root of 2^2 which is a + + align:start position:0% +be the square root of 2^2 which is a + + + align:start position:0% +be the square root of 2^2 which is a +over two and sure enough what's the + + align:start position:0% +over two and sure enough what's the + + + align:start position:0% +over two and sure enough what's the +distance between o20 and the adjacent + + align:start position:0% +distance between o20 and the adjacent + + + align:start position:0% +distance between o20 and the adjacent +plane comparable to it it's a it's only + + align:start position:0% +plane comparable to it it's a it's only + + + align:start position:0% +plane comparable to it it's a it's only +half a lattice constant so in essence if + + align:start position:0% +half a lattice constant so in essence if + + + align:start position:0% +half a lattice constant so in essence if +you look here every o2o plane every o2o + + align:start position:0% +you look here every o2o plane every o2o + + + align:start position:0% +you look here every o2o plane every o2o +plane plane is only half a lattice + + align:start position:0% +plane plane is only half a lattice + + + align:start position:0% +plane plane is only half a lattice +constant away every 010 plane is a full + + align:start position:0% +constant away every 010 plane is a full + + + align:start position:0% +constant away every 010 plane is a full +lattice constant so what you're really + + align:start position:0% +lattice constant so what you're really + + + align:start position:0% +lattice constant so what you're really +seeing then is that the the distance d + + align:start position:0% +seeing then is that the the distance d + + + align:start position:0% +seeing then is that the the distance d +goes down the distance between planes + + align:start position:0% +goes down the distance between planes + + + align:start position:0% +goes down the distance between planes +goes down + + align:start position:0% +goes down + + + align:start position:0% +goes down +as the Miller index goes up and what's + + align:start position:0% +as the Miller index goes up and what's + + + align:start position:0% +as the Miller index goes up and what's +that what's the lowest Miller index the + + align:start position:0% +that what's the lowest Miller index the + + + align:start position:0% +that what's the lowest Miller index the +lowest Miller index is + + align:start position:0% +lowest Miller index is + + + align:start position:0% +lowest Miller index is +o1 lowest Miller index is o1 so that's a + + align:start position:0% +o1 lowest Miller index is o1 so that's a + + + align:start position:0% +o1 lowest Miller index is o1 so that's a +lattice constant that's the max maximum + + align:start position:0% +lattice constant that's the max maximum + + + align:start position:0% +lattice constant that's the max maximum +separation and I think you can see that + + align:start position:0% +separation and I think you can see that + + + align:start position:0% +separation and I think you can see that +as you move hkl to higher values what + + align:start position:0% +as you move hkl to higher values what + + + align:start position:0% +as you move hkl to higher values what +you're doing is you're cutting at a + + align:start position:0% +you're doing is you're cutting at a + + + align:start position:0% +you're doing is you're cutting at a +higher angular slice and as you cut for + + align:start position:0% +higher angular slice and as you cut for + + + align:start position:0% +higher angular slice and as you cut for +a higher angular slice the distance + + align:start position:0% +a higher angular slice the distance + + + align:start position:0% +a higher angular slice the distance +between successive planes is going to be + + align:start position:0% +between successive planes is going to be + + + align:start position:0% +between successive planes is going to be +reduced mathematically what's going on + + align:start position:0% +reduced mathematically what's going on + + + align:start position:0% +reduced mathematically what's going on +this is getting larger in the + + align:start position:0% +this is getting larger in the + + + align:start position:0% +this is getting larger in the +denominator this is remaining the same + + align:start position:0% +denominator this is remaining the same + + + align:start position:0% +denominator this is remaining the same +so that distance becomes closer and + + align:start position:0% +so that distance becomes closer and + + + align:start position:0% +so that distance becomes closer and +closer together and why am i showing you + + align:start position:0% +closer together and why am i showing you + + + align:start position:0% +closer together and why am i showing you +this because we're going to use it in + + align:start position:0% +this because we're going to use it in + + + align:start position:0% +this because we're going to use it in +the very next unit not three years from + + align:start position:0% +the very next unit not three years from + + + align:start position:0% +the very next unit not three years from +now we're going to use it in the next + + align:start position:0% +now we're going to use it in the next + + + align:start position:0% +now we're going to use it in the next +unit when we take this information and + + align:start position:0% +unit when we take this information and + + + align:start position:0% +unit when we take this information and +characterize crystals and we're going to + + align:start position:0% +characterize crystals and we're going to + + + align:start position:0% +characterize crystals and we're going to +characterize atomic structure by the use + + align:start position:0% +characterize atomic structure by the use + + + align:start position:0% +characterize atomic structure by the use +of something that is comparable in + + align:start position:0% +of something that is comparable in + + + align:start position:0% +of something that is comparable in +dimension right if we're going to + + align:start position:0% +dimension right if we're going to + + + align:start position:0% +dimension right if we're going to +measure the dimension of the human hair + + align:start position:0% +measure the dimension of the human hair + + + align:start position:0% +measure the dimension of the human hair +we're not going to use a yard stick what + + align:start position:0% +we're not going to use a yard stick what + + + align:start position:0% +we're not going to use a yard stick what +kind of numbers are we looking at for + + align:start position:0% +kind of numbers are we looking at for + + + align:start position:0% +kind of numbers are we looking at for +these distances we're looking at + + align:start position:0% +these distances we're looking at + + + align:start position:0% +these distances we're looking at +something down + + align:start position:0% +something down + + + align:start position:0% +something down +around some number of angstroms so we + + align:start position:0% +around some number of angstroms so we + + + align:start position:0% +around some number of angstroms so we +better find some tool that gives me + + align:start position:0% +better find some tool that gives me + + + align:start position:0% +better find some tool that gives me +units of some number of angrum and that + + align:start position:0% +units of some number of angrum and that + + + align:start position:0% +units of some number of angrum and that +tool will be x-rays x-rays so now let's + + align:start position:0% +tool will be x-rays x-rays so now let's + + + align:start position:0% +tool will be x-rays x-rays so now let's +look at + + align:start position:0% +look at + + + align:start position:0% +look at +characterization + + align:start position:0% +characterization + + + align:start position:0% +characterization +characterization of atomic + + align:start position:0% +characterization of atomic + + + align:start position:0% +characterization of atomic +structure by + + align:start position:0% + + + + align:start position:0% + +x-rays so today I want to talk about + + align:start position:0% +x-rays so today I want to talk about + + + align:start position:0% +x-rays so today I want to talk about +this the discovery of X-rays and the + + align:start position:0% +this the discovery of X-rays and the + + + align:start position:0% +this the discovery of X-rays and the +underlying physics and then next day + + align:start position:0% +underlying physics and then next day + + + align:start position:0% +underlying physics and then next day +we're going to look at applications so + + align:start position:0% +we're going to look at applications so + + + align:start position:0% +we're going to look at applications so +first of all what are X-rays x-rays are + + align:start position:0% +first of all what are X-rays x-rays are + + + align:start position:0% +first of all what are X-rays x-rays are +a form of electromagnetic + + align:start position:0% +a form of electromagnetic + + + align:start position:0% +a form of electromagnetic +radiation they're a form of + + align:start position:0% +radiation they're a form of + + + align:start position:0% +radiation they're a form of +electromagnetic + + align:start position:0% + + + + align:start position:0% + +radiation electromagnetic + + align:start position:0% +radiation electromagnetic + + + align:start position:0% +radiation electromagnetic +radiation so what's that mean that means + + align:start position:0% +radiation so what's that mean that means + + + align:start position:0% +radiation so what's that mean that means +all of these formulas apply eal H new + + align:start position:0% +all of these formulas apply eal H new + + + align:start position:0% +all of these formulas apply eal H new +equals HC over Lambda equal HC new bar + + align:start position:0% +equals HC over Lambda equal HC new bar + + + align:start position:0% +equals HC over Lambda equal HC new bar +that applies that applies + + align:start position:0% +that applies that applies + + + align:start position:0% +that applies that applies +and the special characteristic of x-rays + + align:start position:0% +and the special characteristic of x-rays + + + align:start position:0% +and the special characteristic of x-rays +is Lambda is very short and typically + + align:start position:0% +is Lambda is very short and typically + + + align:start position:0% +is Lambda is very short and typically +there's no hard rule on this but just in + + align:start position:0% +there's no hard rule on this but just in + + + align:start position:0% +there's no hard rule on this but just in +round numbers we're looking at between + + align:start position:0% +round numbers we're looking at between + + + align:start position:0% +round numbers we're looking at between +1/ 100th to 100 angstroms it's centered + + align:start position:0% +1/ 100th to 100 angstroms it's centered + + + align:start position:0% +1/ 100th to 100 angstroms it's centered +at about one angstrom where one angstrom + + align:start position:0% +at about one angstrom where one angstrom + + + align:start position:0% +at about one angstrom where one angstrom +is equal to 10us 10 meters I know it's + + align:start position:0% +is equal to 10us 10 meters I know it's + + + align:start position:0% +is equal to 10us 10 meters I know it's +not an SI unit and you know my aversion + + align:start position:0% +not an SI unit and you know my aversion + + + align:start position:0% +not an SI unit and you know my aversion +to the nanometer but I'll put it up here + + align:start position:0% +to the nanometer but I'll put it up here + + + align:start position:0% +to the nanometer but I'll put it up here +because I'm required by the + + align:start position:0% +because I'm required by the + + + align:start position:0% +because I'm required by the +international Union of pure and applied + + align:start position:0% +international Union of pure and applied + + + align:start position:0% +international Union of pure and applied +chemistry and the system international + + align:start position:0% +chemistry and the system international + + + align:start position:0% +chemistry and the system international +to put this cont temptable unit here but + + align:start position:0% +to put this cont temptable unit here but + + + align:start position:0% +to put this cont temptable unit here but +I love the angstrom so this is just my + + align:start position:0% +I love the angstrom so this is just my + + + align:start position:0% +I love the angstrom so this is just my +personal preference okay so let's let's + + align:start position:0% +personal preference okay so let's let's + + + align:start position:0% +personal preference okay so let's let's +plug in a value suppose we have one + + align:start position:0% +plug in a value suppose we have one + + + align:start position:0% +plug in a value suppose we have one +angstrom as the wavelength if I use HC + + align:start position:0% +angstrom as the wavelength if I use HC + + + align:start position:0% +angstrom as the wavelength if I use HC +over Lambda where Lambda equals 1 + + align:start position:0% +over Lambda where Lambda equals 1 + + + align:start position:0% +over Lambda where Lambda equals 1 +angstrom or 10us 10 m I end up with 12,4 + + align:start position:0% +angstrom or 10us 10 m I end up with 12,4 + + + align:start position:0% +angstrom or 10us 10 m I end up with 12,4 +00 electron volts per + + align:start position:0% +00 electron volts per + + + align:start position:0% +00 electron volts per +photon per photon 12,400 electron volts + + align:start position:0% +photon per photon 12,400 electron volts + + + align:start position:0% +photon per photon 12,400 electron volts +per photon and this is clearly going to + + align:start position:0% +per photon and this is clearly going to + + + align:start position:0% +per photon and this is clearly going to +be powerful radiation let's take a look + + align:start position:0% +be powerful radiation let's take a look + + + align:start position:0% +be powerful radiation let's take a look +here I pulled this out of the back of + + align:start position:0% +here I pulled this out of the back of + + + align:start position:0% +here I pulled this out of the back of +the text this has um ionization energies + + align:start position:0% +the text this has um ionization energies + + + align:start position:0% +the text this has um ionization energies +for the first uh Seven Elements so if + + align:start position:0% +for the first uh Seven Elements so if + + + align:start position:0% +for the first uh Seven Elements so if +you if you look here this is the in + + align:start position:0% +you if you look here this is the in + + + align:start position:0% +you if you look here this is the in +green I'm showing the first ionization + + align:start position:0% +green I'm showing the first ionization + + + align:start position:0% +green I'm showing the first ionization +energy and this is right off your + + align:start position:0% +energy and this is right off your + + + align:start position:0% +energy and this is right off your +periodic table right 13.6 electron volts + + align:start position:0% +periodic table right 13.6 electron volts + + + align:start position:0% +periodic table right 13.6 electron volts +I've rounded it to two significant + + align:start position:0% +I've rounded it to two significant + + + align:start position:0% +I've rounded it to two significant +figures so it's 13.6 for hydrogen it's + + align:start position:0% +figures so it's 13.6 for hydrogen it's + + + align:start position:0% +figures so it's 13.6 for hydrogen it's +25 for helium it's five um for lithium + + align:start position:0% +25 for helium it's five um for lithium + + + align:start position:0% +25 for helium it's five um for lithium +and so on so these are these are tiny + + align:start position:0% +and so on so these are these are tiny + + + align:start position:0% +and so on so these are these are tiny +tiny numbers these are electron volts + + align:start position:0% +tiny numbers these are electron volts + + + align:start position:0% +tiny numbers these are electron volts +all right now what we can do is look + + align:start position:0% +all right now what we can do is look + + + align:start position:0% +all right now what we can do is look +down this row this is this is the last + + align:start position:0% +down this row this is this is the last + + + align:start position:0% +down this row this is this is the last +electron to come off okay so the second + + align:start position:0% +electron to come off okay so the second + + + align:start position:0% +electron to come off okay so the second +ionization energy of helium is for a one + + align:start position:0% +ionization energy of helium is for a one + + + align:start position:0% +ionization energy of helium is for a one +electron atom right helium has two + + align:start position:0% +electron atom right helium has two + + + align:start position:0% +electron atom right helium has two +electrons if it loses one it only has + + align:start position:0% +electrons if it loses one it only has + + + align:start position:0% +electrons if it loses one it only has +one left so this is a one electron atom + + align:start position:0% +one left so this is a one electron atom + + + align:start position:0% +one left so this is a one electron atom +this is a one electron atom this is a + + align:start position:0% +this is a one electron atom this is a + + + align:start position:0% +this is a one electron atom this is a +one electron atom and look at the + + align:start position:0% +one electron atom and look at the + + + align:start position:0% +one electron atom and look at the +energies this is for the innermost + + align:start position:0% +energies this is for the innermost + + + align:start position:0% +energies this is for the innermost +electron well one electron atom that'll + + align:start position:0% +electron well one electron atom that'll + + + align:start position:0% +electron well one electron atom that'll +conform to the bore model and sure + + align:start position:0% +conform to the bore model and sure + + + align:start position:0% +conform to the bore model and sure +enough look at the ratios of these + + align:start position:0% +enough look at the ratios of these + + + align:start position:0% +enough look at the ratios of these +numbers these are determined by x-ray + + align:start position:0% +numbers these are determined by x-ray + + + align:start position:0% +numbers these are determined by x-ray +photo electron spectroscopy and roughly + + align:start position:0% +photo electron spectroscopy and roughly + + + align:start position:0% +photo electron spectroscopy and roughly +14 * 4 is 56 so there it is 1 to 4 to 9 + + align:start position:0% +14 * 4 is 56 so there it is 1 to 4 to 9 + + + align:start position:0% +14 * 4 is 56 so there it is 1 to 4 to 9 +to 16 and it's just a manifestation of + + align:start position:0% +to 16 and it's just a manifestation of + + + align:start position:0% +to 16 and it's just a manifestation of +what you've seen as the ground state + + align:start position:0% +what you've seen as the ground state + + + align:start position:0% +what you've seen as the ground state +energy in the bore model goes as the + + align:start position:0% +energy in the bore model goes as the + + + align:start position:0% +energy in the bore model goes as the +square of the atomic number so + + align:start position:0% +square of the atomic number so + + + align:start position:0% +square of the atomic number so +everything's making sense but what I + + align:start position:0% +everything's making sense but what I + + + align:start position:0% +everything's making sense but what I +draw your attention to is look this is + + align:start position:0% +draw your attention to is look this is + + + align:start position:0% +draw your attention to is look this is +the innermost held electron of nitrogen + + align:start position:0% +the innermost held electron of nitrogen + + + align:start position:0% +the innermost held electron of nitrogen +it's 668 electron volts and I've got + + align:start position:0% +it's 668 electron volts and I've got + + + align:start position:0% +it's 668 electron volts and I've got +12,400 this has enormous power this has + + align:start position:0% +12,400 this has enormous power this has + + + align:start position:0% +12,400 this has enormous power this has +the power to + + align:start position:0% +the power to + + + align:start position:0% +the power to +ionize ionize inner shell + + align:start position:0% +ionize ionize inner shell + + + align:start position:0% +ionize ionize inner shell +electrons this is like a bowling alley + + align:start position:0% +electrons this is like a bowling alley + + + align:start position:0% +electrons this is like a bowling alley +this is like a bowling alley and all the + + align:start position:0% +this is like a bowling alley and all the + + + align:start position:0% +this is like a bowling alley and all the +pins are going flying here this is + + align:start position:0% +pins are going flying here this is + + + align:start position:0% +pins are going flying here this is +incredible + + align:start position:0% +incredible + + + align:start position:0% +incredible +energy so what's the what's the + + align:start position:0% +energy so what's the what's the + + + align:start position:0% +energy so what's the what's the +underlying principles here well I think + + align:start position:0% +underlying principles here well I think + + + align:start position:0% +underlying principles here well I think +we have to start with a history lesson + + align:start position:0% +we have to start with a history lesson + + + align:start position:0% +we have to start with a history lesson +so we'll start with a history lesson + + align:start position:0% +so we'll start with a history lesson + + + align:start position:0% +so we'll start with a history lesson +we'll go back to November 8th 1895 it + + align:start position:0% +we'll go back to November 8th 1895 it + + + align:start position:0% +we'll go back to November 8th 1895 it +was a dark and stormy night really it + + align:start position:0% +was a dark and stormy night really it + + + align:start position:0% +was a dark and stormy night really it +was a dark and stormy night on November + + align:start position:0% +was a dark and stormy night on November + + + align:start position:0% +was a dark and stormy night on November +8th 189 95 in + + align:start position:0% +8th 189 95 in + + + align:start position:0% +8th 189 95 in +verburg verburg in + + align:start position:0% +verburg verburg in + + + align:start position:0% +verburg verburg in +Bavaria which is now part of Germany and + + align:start position:0% +Bavaria which is now part of Germany and + + + align:start position:0% +Bavaria which is now part of Germany and +there was a physics Professor there + + align:start position:0% +there was a physics Professor there + + + align:start position:0% +there was a physics Professor there +physics Professor there by the name of + + align:start position:0% +physics Professor there by the name of + + + align:start position:0% +physics Professor there by the name of +Willam + + align:start position:0% + + + + align:start position:0% + +renen William + + align:start position:0% +renen William + + + align:start position:0% +renen William +renin and he was doing research as many + + align:start position:0% +renin and he was doing research as many + + + align:start position:0% +renin and he was doing research as many +people were at that time on gas + + align:start position:0% +people were at that time on gas + + + align:start position:0% +people were at that time on gas +discharge tub we've seen gas discharge + + align:start position:0% +discharge tub we've seen gas discharge + + + align:start position:0% +discharge tub we've seen gas discharge +tubes a number of times in 3091 and + + align:start position:0% +tubes a number of times in 3091 and + + + align:start position:0% +tubes a number of times in 3091 and +renen was part of that army of + + align:start position:0% +renen was part of that army of + + + align:start position:0% +renen was part of that army of +researchers and what Ren's specialty was + + align:start position:0% +researchers and what Ren's specialty was + + + align:start position:0% +researchers and what Ren's specialty was +he was pursuing gas discharge spectral + + align:start position:0% +he was pursuing gas discharge spectral + + + align:start position:0% +he was pursuing gas discharge spectral +analysis under reduced + + align:start position:0% +analysis under reduced + + + align:start position:0% +analysis under reduced +pressure so he was pumping down with a + + align:start position:0% +pressure so he was pumping down with a + + + align:start position:0% +pressure so he was pumping down with a +vacuum pump to get the gas pressure very + + align:start position:0% +vacuum pump to get the gas pressure very + + + align:start position:0% +vacuum pump to get the gas pressure very +very low and very very high voltage + + align:start position:0% +very low and very very high voltage + + + align:start position:0% +very low and very very high voltage +that's what his take was he wanted to + + align:start position:0% +that's what his take was he wanted to + + + align:start position:0% +that's what his take was he wanted to +look at high voltage and very very low + + align:start position:0% +look at high voltage and very very low + + + align:start position:0% +look at high voltage and very very low +pressure pressure and let's take a look + + align:start position:0% +pressure pressure and let's take a look + + + align:start position:0% +pressure pressure and let's take a look +at what his his apparatus looked like um + + align:start position:0% +at what his his apparatus looked like um + + + align:start position:0% +at what his his apparatus looked like um +well we'll start with the the tube as + + align:start position:0% +well we'll start with the the tube as + + + align:start position:0% +well we'll start with the the tube as +you've seen many times we'll put a we'll + + align:start position:0% +you've seen many times we'll put a we'll + + + align:start position:0% +you've seen many times we'll put a we'll +put the cathode to the left we'll put + + align:start position:0% +put the cathode to the left we'll put + + + align:start position:0% +put the cathode to the left we'll put +the anode to the + + align:start position:0% +the anode to the + + + align:start position:0% +the anode to the +right and he had the laboratory on the + + align:start position:0% +right and he had the laboratory on the + + + align:start position:0% +right and he had the laboratory on the +second floor laboratory in the second + + align:start position:0% +second floor laboratory in the second + + + align:start position:0% +second floor laboratory in the second +floor his apartment was on the first + + align:start position:0% +floor his apartment was on the first + + + align:start position:0% +floor his apartment was on the first +floor and down in the basement he had a + + align:start position:0% +floor and down in the basement he had a + + + align:start position:0% +floor and down in the basement he had a +bunch of uh uh batteries chromic acid + + align:start position:0% +bunch of uh uh batteries chromic acid + + + align:start position:0% +bunch of uh uh batteries chromic acid +chromic acid in open beakers uh down in + + align:start position:0% +chromic acid in open beakers uh down in + + + align:start position:0% +chromic acid in open beakers uh down in +the basement so let's indicate that with + + align:start position:0% +the basement so let's indicate that with + + + align:start position:0% +the basement so let's indicate that with +the classical symbol and this altogether + + align:start position:0% +the classical symbol and this altogether + + + align:start position:0% +the classical symbol and this altogether +put out about 20 volts and then what he + + align:start position:0% +put out about 20 volts and then what he + + + align:start position:0% +put out about 20 volts and then what he +did is he was a professor of physics who + + align:start position:0% +did is he was a professor of physics who + + + align:start position:0% +did is he was a professor of physics who +understood some electrical engineering + + align:start position:0% +understood some electrical engineering + + + align:start position:0% +understood some electrical engineering +so he had a choke coil here so the choke + + align:start position:0% +so he had a choke coil here so the choke + + + align:start position:0% +so he had a choke coil here so the choke +coil would would take the the current + + align:start position:0% +coil would would take the the current + + + align:start position:0% +coil would would take the the current +store up and eight times a second eight + + align:start position:0% +store up and eight times a second eight + + + align:start position:0% +store up and eight times a second eight +times a second + + align:start position:0% +times a second + + + align:start position:0% +times a second +it would discharge and it would + + align:start position:0% +it would discharge and it would + + + align:start position:0% +it would discharge and it would +discharge at 35,000 volts so he could + + align:start position:0% +discharge at 35,000 volts so he could + + + align:start position:0% +discharge at 35,000 volts so he could +take 20 volts and up it to uh 35,000 by + + align:start position:0% +take 20 volts and up it to uh 35,000 by + + + align:start position:0% +take 20 volts and up it to uh 35,000 by +the use of this choke coil so eight + + align:start position:0% +the use of this choke coil so eight + + + align:start position:0% +the use of this choke coil so eight +times a second he had 35,000 volts + + align:start position:0% +times a second he had 35,000 volts + + + align:start position:0% +times a second he had 35,000 volts +coming off the cathode here so you've + + align:start position:0% +coming off the cathode here so you've + + + align:start position:0% +coming off the cathode here so you've +got Bam Bam Bam Bam but speed that up + + align:start position:0% +got Bam Bam Bam Bam but speed that up + + + align:start position:0% +got Bam Bam Bam Bam but speed that up +about eight times and that's what that's + + align:start position:0% +about eight times and that's what that's + + + align:start position:0% +about eight times and that's what that's +what's going on and so with 35,000 volts + + align:start position:0% +what's going on and so with 35,000 volts + + + align:start position:0% +what's going on and so with 35,000 volts +he launches electrons off the cathode + + align:start position:0% +he launches electrons off the cathode + + + align:start position:0% +he launches electrons off the cathode +and they go zooming across what is very + + align:start position:0% +and they go zooming across what is very + + + align:start position:0% +and they go zooming across what is very +very low pressure gas and crash into the + + align:start position:0% +very low pressure gas and crash into the + + + align:start position:0% +very low pressure gas and crash into the +anode and in the meantime to keep this + + align:start position:0% +anode and in the meantime to keep this + + + align:start position:0% +anode and in the meantime to keep this +thing dynamically at low pressure this + + align:start position:0% +thing dynamically at low pressure this + + + align:start position:0% +thing dynamically at low pressure this +goes to a vacuum + + align:start position:0% +goes to a vacuum + + + align:start position:0% +goes to a vacuum +pump vacuum pump to keep this thing + + align:start position:0% +pump vacuum pump to keep this thing + + + align:start position:0% +pump vacuum pump to keep this thing +pumped down as low as he + + align:start position:0% +pumped down as low as he + + + align:start position:0% +pumped down as low as he +can and he was measuring what was going + + align:start position:0% +can and he was measuring what was going + + + align:start position:0% +can and he was measuring what was going +on inside this gas tube and so he had a + + align:start position:0% +on inside this gas tube and so he had a + + + align:start position:0% +on inside this gas tube and so he had a +detector and his detector was over here + + align:start position:0% +detector and his detector was over here + + + align:start position:0% +detector and his detector was over here +the detector was off to the side and the + + align:start position:0% +the detector was off to the side and the + + + align:start position:0% +the detector was off to the side and the +detector consisted of of either a piece + + align:start position:0% +detector consisted of of either a piece + + + align:start position:0% +detector consisted of of either a piece +of cloth or a paper towel which had been + + align:start position:0% +of cloth or a paper towel which had been + + + align:start position:0% +of cloth or a paper towel which had been +painted with a a chemical that would + + align:start position:0% +painted with a a chemical that would + + + align:start position:0% +painted with a a chemical that would +glow when it was struck by something + + align:start position:0% +glow when it was struck by something + + + align:start position:0% +glow when it was struck by something +what would the something be it something + + align:start position:0% +what would the something be it something + + + align:start position:0% +what would the something be it something +would + + align:start position:0% +would + + + align:start position:0% +would +be electrons or photons that have an + + align:start position:0% +be electrons or photons that have an + + + align:start position:0% +be electrons or photons that have an +energy high enough to cause excitation + + align:start position:0% +energy high enough to cause excitation + + + align:start position:0% +energy high enough to cause excitation +of something in the paint and then + + align:start position:0% +of something in the paint and then + + + align:start position:0% +of something in the paint and then +reemission in the visible doesn't do any + + align:start position:0% +reemission in the visible doesn't do any + + + align:start position:0% +reemission in the visible doesn't do any +good to excite electrons in the detector + + align:start position:0% +good to excite electrons in the detector + + + align:start position:0% +good to excite electrons in the detector +to have them Reit outside the visible + + align:start position:0% +to have them Reit outside the visible + + + align:start position:0% +to have them Reit outside the visible +okay so that's what's going on so this + + align:start position:0% +okay so that's what's going on so this + + + align:start position:0% +okay so that's what's going on so this +is this was paper or + + align:start position:0% +is this was paper or + + + align:start position:0% +is this was paper or +cloth and it was painted with an aquous + + align:start position:0% +cloth and it was painted with an aquous + + + align:start position:0% +cloth and it was painted with an aquous +solution of + + align:start position:0% +solution of + + + align:start position:0% +solution of +barium platino + + align:start position:0% +barium platino + + + align:start position:0% +barium platino +cyanide yummy stuff barium platino + + align:start position:0% +cyanide yummy stuff barium platino + + + align:start position:0% +cyanide yummy stuff barium platino +cyanide which glows + + align:start position:0% +cyanide which glows + + + align:start position:0% +cyanide which glows +green it glows green when it's + + align:start position:0% +green it glows green when it's + + + align:start position:0% +green it glows green when it's +excited and uh this is called a + + align:start position:0% +excited and uh this is called a + + + align:start position:0% +excited and uh this is called a +scintillation screen scintillation + + align:start position:0% +scintillation screen scintillation + + + align:start position:0% +scintillation screen scintillation +screen comes from the Latin word for + + align:start position:0% +screen comes from the Latin word for + + + align:start position:0% +screen comes from the Latin word for +spark cintilla means spark in Latin so + + align:start position:0% +spark cintilla means spark in Latin so + + + align:start position:0% +spark cintilla means spark in Latin so +when the screen is struck by some form + + align:start position:0% +when the screen is struck by some form + + + align:start position:0% +when the screen is struck by some form +of energy uh it will glow and so he' had + + align:start position:0% +of energy uh it will glow and so he' had + + + align:start position:0% +of energy uh it will glow and so he' had +dinner and it was up in the up on the + + align:start position:0% +dinner and it was up in the up on the + + + align:start position:0% +dinner and it was up in the up on the +second floor cranking away after dinner + + align:start position:0% +second floor cranking away after dinner + + + align:start position:0% +second floor cranking away after dinner +and it was uh it was dark it was raining + + align:start position:0% +and it was uh it was dark it was raining + + + align:start position:0% +and it was uh it was dark it was raining +had the windows open and a street light + + align:start position:0% +had the windows open and a street light + + + align:start position:0% +had the windows open and a street light +was was coming in oh by the way renen + + align:start position:0% +was was coming in oh by the way renen + + + align:start position:0% +was was coming in oh by the way renen +suffered from daltonism he was red green + + align:start position:0% +suffered from daltonism he was red green + + + align:start position:0% +suffered from daltonism he was red green +colorblind and this was a green screen + + align:start position:0% +colorblind and this was a green screen + + + align:start position:0% +colorblind and this was a green screen +and and with 35,000 volts even at + + align:start position:0% +and and with 35,000 volts even at + + + align:start position:0% +and and with 35,000 volts even at +reduced pressure given the capacity of + + align:start position:0% +reduced pressure given the capacity of + + + align:start position:0% +reduced pressure given the capacity of +those days for vacuum pumps he still had + + align:start position:0% +those days for vacuum pumps he still had + + + align:start position:0% +those days for vacuum pumps he still had +a lot of glow from the the the tube so + + align:start position:0% +a lot of glow from the the the tube so + + + align:start position:0% +a lot of glow from the the the tube so +the tube is glowing um he's got a street + + align:start position:0% +the tube is glowing um he's got a street + + + align:start position:0% +the tube is glowing um he's got a street +light in the background so he decides to + + align:start position:0% +light in the background so he decides to + + + align:start position:0% +light in the background so he decides to +close the drapes and and uh take out the + + align:start position:0% +close the drapes and and uh take out the + + + align:start position:0% +close the drapes and and uh take out the +street light and then furthermore he + + align:start position:0% +street light and then furthermore he + + + align:start position:0% +street light and then furthermore he +decides to darken darken the the room so + + align:start position:0% +decides to darken darken the the room so + + + align:start position:0% +decides to darken darken the the room so +he he puts a cardboard box over the a + + align:start position:0% +he he puts a cardboard box over the a + + + align:start position:0% +he he puts a cardboard box over the a +tube so now the tube is enclosed in a + + align:start position:0% +tube so now the tube is enclosed in a + + + align:start position:0% +tube so now the tube is enclosed in a +cardboard box so it's it's not glowing + + align:start position:0% +cardboard box so it's it's not glowing + + + align:start position:0% +cardboard box so it's it's not glowing +visibly to him it's glowing inside the + + align:start position:0% +visibly to him it's glowing inside the + + + align:start position:0% +visibly to him it's glowing inside the +box and he continues to see + + align:start position:0% +box and he continues to see + + + align:start position:0% +box and he continues to see +scintillation continues to see things + + align:start position:0% +scintillation continues to see things + + + align:start position:0% +scintillation continues to see things +glowing so he says + + align:start position:0% +glowing so he says + + + align:start position:0% +glowing so he says +hm something that's something + + align:start position:0% +hm something that's something + + + align:start position:0% +hm something that's something +interesting the other thing that + + align:start position:0% +interesting the other thing that + + + align:start position:0% +interesting the other thing that +happened was kind of interesting his + + align:start position:0% +happened was kind of interesting his + + + align:start position:0% +happened was kind of interesting his +graduate student who had prepared some + + align:start position:0% +graduate student who had prepared some + + + align:start position:0% +graduate student who had prepared some +of the apparatus I guess he was + + align:start position:0% +of the apparatus I guess he was + + + align:start position:0% +of the apparatus I guess he was +practicing painting the scintillation + + align:start position:0% +practicing painting the scintillation + + + align:start position:0% +practicing painting the scintillation +screen so what the student had done was + + align:start position:0% +screen so what the student had done was + + + align:start position:0% +screen so what the student had done was +to uh paint the letter + + align:start position:0% +to uh paint the letter + + + align:start position:0% +to uh paint the letter +A on a paper towel and he left the paper + + align:start position:0% +A on a paper towel and he left the paper + + + align:start position:0% +A on a paper towel and he left the paper +towel on the lab bench so now rin's got + + align:start position:0% +towel on the lab bench so now rin's got + + + align:start position:0% +towel on the lab bench so now rin's got +the the tube enclosed in cardboard this + + align:start position:0% +the the tube enclosed in cardboard this + + + align:start position:0% +the the tube enclosed in cardboard this +thing's glowing he looks down he sees + + align:start position:0% +thing's glowing he looks down he sees + + + align:start position:0% +thing's glowing he looks down he sees +the letter A the letter a is glowing and + + align:start position:0% +the letter A the letter a is glowing and + + + align:start position:0% +the letter A the letter a is glowing and +he's going wait a minute this is crazy + + align:start position:0% +he's going wait a minute this is crazy + + + align:start position:0% +he's going wait a minute this is crazy +so he says all right so he takes a piece + + align:start position:0% +so he says all right so he takes a piece + + + align:start position:0% +so he says all right so he takes a piece +of black paper and he puts it here in + + align:start position:0% +of black paper and he puts it here in + + + align:start position:0% +of black paper and he puts it here in +between the tube and the screen and the + + align:start position:0% +between the tube and the screen and the + + + align:start position:0% +between the tube and the screen and the +screen continues to glow and then he + + align:start position:0% +screen continues to glow and then he + + + align:start position:0% +screen continues to glow and then he +says uh he takes out he had a deck of + + align:start position:0% +says uh he takes out he had a deck of + + + align:start position:0% +says uh he takes out he had a deck of +playing cards in his in his uh lab so + + align:start position:0% +playing cards in his in his uh lab so + + + align:start position:0% +playing cards in his in his uh lab so +don't laugh that's how mlay have + + align:start position:0% +don't laugh that's how mlay have + + + align:start position:0% +don't laugh that's how mlay have +discovered periodicity so so he takes a + + align:start position:0% +discovered periodicity so so he takes a + + + align:start position:0% +discovered periodicity so so he takes a +playing card he puts the playing card in + + align:start position:0% +playing card he puts the playing card in + + + align:start position:0% +playing card he puts the playing card in +front and the tube continues to glow and + + align:start position:0% +front and the tube continues to glow and + + + align:start position:0% +front and the tube continues to glow and +then he takes a book and he puts a book + + align:start position:0% +then he takes a book and he puts a book + + + align:start position:0% +then he takes a book and he puts a book +in between and the tube continues to + + align:start position:0% +in between and the tube continues to + + + align:start position:0% +in between and the tube continues to +Glow so he's getting wait a minute so + + align:start position:0% +Glow so he's getting wait a minute so + + + align:start position:0% +Glow so he's getting wait a minute so +then he grabs a piece of lead foil and + + align:start position:0% +then he grabs a piece of lead foil and + + + align:start position:0% +then he grabs a piece of lead foil and +he puts the lead foil in here and what + + align:start position:0% +he puts the lead foil in here and what + + + align:start position:0% +he puts the lead foil in here and what +happens is that where the lead foil is + + align:start position:0% +happens is that where the lead foil is + + + align:start position:0% +happens is that where the lead foil is +the screen is not glowing but then he + + align:start position:0% +the screen is not glowing but then he + + + align:start position:0% +the screen is not glowing but then he +sees the outline of the bones of his + + align:start position:0% +sees the outline of the bones of his + + + align:start position:0% +sees the outline of the bones of his +hand on the lead holding the lead + + align:start position:0% +hand on the lead holding the lead + + + align:start position:0% +hand on the lead holding the lead +foil so all of this stuff is going on + + align:start position:0% +foil so all of this stuff is going on + + + align:start position:0% +foil so all of this stuff is going on +and he just he just goes goes to town he + + align:start position:0% +and he just he just goes goes to town he + + + align:start position:0% +and he just he just goes goes to town he +says you know what I've got to I've got + + align:start position:0% +says you know what I've got to I've got + + + align:start position:0% +says you know what I've got to I've got +to this can't be electrons because + + align:start position:0% +to this can't be electrons because + + + align:start position:0% +to this can't be electrons because +electrons can't live in air they'll be + + align:start position:0% +electrons can't live in air they'll be + + + align:start position:0% +electrons can't live in air they'll be +stopped by air so he knew about radio + + align:start position:0% +stopped by air so he knew about radio + + + align:start position:0% +stopped by air so he knew about radio +waves from Herz and he said could this + + align:start position:0% +waves from Herz and he said could this + + + align:start position:0% +waves from Herz and he said could this +be some form of mysterious radiation + + align:start position:0% +be some form of mysterious radiation + + + align:start position:0% +be some form of mysterious radiation +that's capable and he was really afraid + + align:start position:0% +that's capable and he was really afraid + + + align:start position:0% +that's capable and he was really afraid +to say this a form of radiation that's + + align:start position:0% +to say this a form of radiation that's + + + align:start position:0% +to say this a form of radiation that's +capable of penetrating + + align:start position:0% +capable of penetrating + + + align:start position:0% +capable of penetrating +matter it's 1895 you're going to come + + align:start position:0% +matter it's 1895 you're going to come + + + align:start position:0% +matter it's 1895 you're going to come +out publicly and say I have a form of + + align:start position:0% +out publicly and say I have a form of + + + align:start position:0% +out publicly and say I have a form of +radiation that can penetrate matter so + + align:start position:0% +radiation that can penetrate matter so + + + align:start position:0% +radiation that can penetrate matter so +he gets a magnet out he moves a magnet + + align:start position:0% +he gets a magnet out he moves a magnet + + + align:start position:0% +he gets a magnet out he moves a magnet +it doesn't change so the stuff isn't + + align:start position:0% +it doesn't change so the stuff isn't + + + align:start position:0% +it doesn't change so the stuff isn't +sensitive to magnetic field but if he + + align:start position:0% +sensitive to magnetic field but if he + + + align:start position:0% +sensitive to magnetic field but if he +puts a magnet here of course he gets + + align:start position:0% +puts a magnet here of course he gets + + + align:start position:0% +puts a magnet here of course he gets +changes uh he can't see this stuff he + + align:start position:0% +changes uh he can't see this stuff he + + + align:start position:0% +changes uh he can't see this stuff he +can only see evidence of it it's + + align:start position:0% +can only see evidence of it it's + + + align:start position:0% +can only see evidence of it it's +mysterious it's mysterious so he calls + + align:start position:0% +mysterious it's mysterious so he calls + + + align:start position:0% +mysterious it's mysterious so he calls +it X the unknown quantity it's X + + align:start position:0% +it X the unknown quantity it's X + + + align:start position:0% +it X the unknown quantity it's X +radiation X radiation this is November + + align:start position:0% +radiation X radiation this is November + + + align:start position:0% +radiation X radiation this is November +8th + + align:start position:0% +8th + + + align:start position:0% +8th +1895 and to show you what a what a great + + align:start position:0% +1895 and to show you what a what a great + + + align:start position:0% +1895 and to show you what a what a great +scientist he was rather than rushing to + + align:start position:0% +scientist he was rather than rushing to + + + align:start position:0% +scientist he was rather than rushing to +publication he spends all of November + + align:start position:0% +publication he spends all of November + + + align:start position:0% +publication he spends all of November +and December repeating the experiment + + align:start position:0% +and December repeating the experiment + + + align:start position:0% +and December repeating the experiment +and trying it in different ways until + + align:start position:0% +and trying it in different ways until + + + align:start position:0% +and trying it in different ways until +he's convinced that the effect is real + + align:start position:0% +he's convinced that the effect is real + + + align:start position:0% +he's convinced that the effect is real +and then around Christmas time of 1895 + + align:start position:0% +and then around Christmas time of 1895 + + + align:start position:0% +and then around Christmas time of 1895 +he sends off a manuscript and it's + + align:start position:0% +he sends off a manuscript and it's + + + align:start position:0% +he sends off a manuscript and it's +published in the first week of January + + align:start position:0% +published in the first week of January + + + align:start position:0% +published in the first week of January +of + + align:start position:0% +of + + + align:start position:0% +of +1896 and it takes the World by storm + + align:start position:0% +1896 and it takes the World by storm + + + align:start position:0% +1896 and it takes the World by storm +he's announcing that there's a form of + + align:start position:0% +he's announcing that there's a form of + + + align:start position:0% +he's announcing that there's a form of +radiation that can penetrate matter and + + align:start position:0% +radiation that can penetrate matter and + + + align:start position:0% +radiation that can penetrate matter and +furthermore he's got an x-ray of a human + + align:start position:0% +furthermore he's got an x-ray of a human + + + align:start position:0% +furthermore he's got an x-ray of a human +hand you know this is the 1890s so PE + + align:start position:0% +hand you know this is the 1890s so PE + + + align:start position:0% +hand you know this is the 1890s so PE +people are you know very prude very + + align:start position:0% +people are you know very prude very + + + align:start position:0% +people are you know very prude very +private he's got a form of radiation + + align:start position:0% +private he's got a form of radiation + + + align:start position:0% +private he's got a form of radiation +that can look inside the human body this + + align:start position:0% +that can look inside the human body this + + + align:start position:0% +that can look inside the human body this +is really shocking + + align:start position:0% +is really shocking + + + align:start position:0% +is really shocking +stuff so already uh on January + + align:start position:0% +stuff so already uh on January + + + align:start position:0% +stuff so already uh on January +16th January 16th + + align:start position:0% +16th January 16th + + + align:start position:0% +16th January 16th +1896 was an article in New York Times + + align:start position:0% +1896 was an article in New York Times + + + align:start position:0% +1896 was an article in New York Times +article in New York Times about this + + align:start position:0% +article in New York Times about this + + + align:start position:0% +article in New York Times about this +stuff mysterious form of + + align:start position:0% +stuff mysterious form of + + + align:start position:0% +stuff mysterious form of +radiation well by the way you know he + + align:start position:0% +radiation well by the way you know he + + + align:start position:0% +radiation well by the way you know he +was doing his experiments how was he + + align:start position:0% +was doing his experiments how was he + + + align:start position:0% +was doing his experiments how was he +recording his results he was recording + + align:start position:0% +recording his results he was recording + + + align:start position:0% +recording his results he was recording +his results on photographic film and his + + align:start position:0% +his results on photographic film and his + + + align:start position:0% +his results on photographic film and his +photographic film was fogging he had his + + align:start position:0% +photographic film was fogging he had his + + + align:start position:0% +photographic film was fogging he had his +photographic film stored in a cabinet on + + align:start position:0% +photographic film stored in a cabinet on + + + align:start position:0% +photographic film stored in a cabinet on +the other side of the lab and half of + + align:start position:0% +the other side of the lab and half of + + + align:start position:0% +the other side of the lab and half of +the time he take the photographic film + + align:start position:0% +the time he take the photographic film + + + align:start position:0% +the time he take the photographic film +out and it was fogged so whatever this + + align:start position:0% +out and it was fogged so whatever this + + + align:start position:0% +out and it was fogged so whatever this +stuff is it's it's penetrating + + align:start position:0% +stuff is it's it's penetrating + + + align:start position:0% +stuff is it's it's penetrating +everything it's penetrating the doors of + + align:start position:0% +everything it's penetrating the doors of + + + align:start position:0% +everything it's penetrating the doors of +his file cabinet they weren't steel case + + align:start position:0% +his file cabinet they weren't steel case + + + align:start position:0% +his file cabinet they weren't steel case +they were probably wooden file cabinets + + align:start position:0% +they were probably wooden file cabinets + + + align:start position:0% +they were probably wooden file cabinets +right so widespread widespread + + align:start position:0% +right so widespread widespread + + + align:start position:0% +right so widespread widespread +adoption widespread adoption some of + + align:start position:0% +adoption widespread adoption some of + + + align:start position:0% +adoption widespread adoption some of +it + + align:start position:0% +it + + + align:start position:0% +it +silly uh what's some of the silly ones + + align:start position:0% +silly uh what's some of the silly ones + + + align:start position:0% +silly uh what's some of the silly ones +in London there was a manufacture + + align:start position:0% +in London there was a manufacture + + + align:start position:0% +in London there was a manufacture +announced remember this is prudish + + align:start position:0% +announced remember this is prudish + + + align:start position:0% +announced remember this is prudish +Victorian England that he could uh sell + + align:start position:0% +Victorian England that he could uh sell + + + align:start position:0% +Victorian England that he could uh sell +you X-ray proof ladies + + align:start position:0% + + + + align:start position:0% + +underwear in France there was no such + + align:start position:0% +underwear in France there was no such + + + align:start position:0% +underwear in France there was no such +thing the French don't care about such + + align:start position:0% +thing the French don't care about such + + + align:start position:0% +thing the French don't care about such +matters so instead this was uh remember + + align:start position:0% +matters so instead this was uh remember + + + align:start position:0% +matters so instead this was uh remember +the French uh deare had invented haly + + align:start position:0% +the French uh deare had invented haly + + + align:start position:0% +the French uh deare had invented haly +photography so someone in France offered + + align:start position:0% +photography so someone in France offered + + + align:start position:0% +photography so someone in France offered +to ex-ray the human soul this is very + + align:start position:0% +to ex-ray the human soul this is very + + + align:start position:0% +to ex-ray the human soul this is very +good um I'm ashamed to say what happened + + align:start position:0% +good um I'm ashamed to say what happened + + + align:start position:0% +good um I'm ashamed to say what happened +in the United States the New York uh + + align:start position:0% +in the United States the New York uh + + + align:start position:0% +in the United States the New York uh +City College of Physicians and surgeons + + align:start position:0% +City College of Physicians and surgeons + + + align:start position:0% +City College of Physicians and surgeons +announced that they would use x-ray to + + align:start position:0% +announced that they would use x-ray to + + + align:start position:0% +announced that they would use x-ray to +project um anatomical diagrams from + + align:start position:0% +project um anatomical diagrams from + + + align:start position:0% +project um anatomical diagrams from +textbooks onto the brains of medical + + align:start position:0% +textbooks onto the brains of medical + + + align:start position:0% +textbooks onto the brains of medical +students thereby creating and I quote an + + align:start position:0% +students thereby creating and I quote an + + + align:start position:0% +students thereby creating and I quote an +enduring + + align:start position:0% + + + + align:start position:0% + +impression in Iowa somebody offered to + + align:start position:0% +impression in Iowa somebody offered to + + + align:start position:0% +impression in Iowa somebody offered to +x-ray copper pennies and thereby turn + + align:start position:0% +x-ray copper pennies and thereby turn + + + align:start position:0% +x-ray copper pennies and thereby turn +them into gold so that's that's what + + align:start position:0% +them into gold so that's that's what + + + align:start position:0% +them into gold so that's that's what +happened but seriously what what really + + align:start position:0% +happened but seriously what what really + + + align:start position:0% +happened but seriously what what really +did happen very quickly was the use of + + align:start position:0% +did happen very quickly was the use of + + + align:start position:0% +did happen very quickly was the use of +x-rays as a diagnostic tool already in + + align:start position:0% +x-rays as a diagnostic tool already in + + + align:start position:0% +x-rays as a diagnostic tool already in +February of uh 1896 there was a Scottish + + align:start position:0% +February of uh 1896 there was a Scottish + + + align:start position:0% +February of uh 1896 there was a Scottish +physician who used X-rays and look it's + + align:start position:0% +physician who used X-rays and look it's + + + align:start position:0% +physician who used X-rays and look it's +simple it's just that you could do this + + align:start position:0% +simple it's just that you could do this + + + align:start position:0% +simple it's just that you could do this +in a high school I mean what is it you + + align:start position:0% +in a high school I mean what is it you + + + align:start position:0% +in a high school I mean what is it you +know it's just a gas discharge tube pair + + align:start position:0% +know it's just a gas discharge tube pair + + + align:start position:0% +know it's just a gas discharge tube pair +of electrodes with a feed through and + + align:start position:0% +of electrodes with a feed through and + + + align:start position:0% +of electrodes with a feed through and +you know he's got 35,000 volts I mean + + align:start position:0% +you know he's got 35,000 volts I mean + + + align:start position:0% +you know he's got 35,000 volts I mean +that's kind of stuff that comes off the + + align:start position:0% +that's kind of stuff that comes off the + + + align:start position:0% +that's kind of stuff that comes off the +chassis of your your television set this + + align:start position:0% +chassis of your your television set this + + + align:start position:0% +chassis of your your television set this +is trivial stuff know so people are + + align:start position:0% +is trivial stuff know so people are + + + align:start position:0% +is trivial stuff know so people are +putting these things everywhere they're + + align:start position:0% +putting these things everywhere they're + + + align:start position:0% +putting these things everywhere they're +sitting in offices an open view nobody + + align:start position:0% +sitting in offices an open view nobody + + + align:start position:0% +sitting in offices an open view nobody +knew so this physician uh had a + + align:start position:0% +knew so this physician uh had a + + + align:start position:0% +knew so this physician uh had a +seamstress come to him she was involved + + align:start position:0% +seamstress come to him she was involved + + + align:start position:0% +seamstress come to him she was involved +in an industrial accident in a mill uh a + + align:start position:0% +in an industrial accident in a mill uh a + + + align:start position:0% +in an industrial accident in a mill uh a +needle broke off in her hand now how + + align:start position:0% +needle broke off in her hand now how + + + align:start position:0% +needle broke off in her hand now how +would you find the needle in a hand you + + align:start position:0% +would you find the needle in a hand you + + + align:start position:0% +would you find the needle in a hand you +can't well x-ray they identifi the + + align:start position:0% +can't well x-ray they identifi the + + + align:start position:0% +can't well x-ray they identifi the +location of the needle performed the + + align:start position:0% +location of the needle performed the + + + align:start position:0% +location of the needle performed the +surgery Boom for dental applications it + + align:start position:0% +surgery Boom for dental applications it + + + align:start position:0% +surgery Boom for dental applications it +was immediately adopted they were + + align:start position:0% +was immediately adopted they were + + + align:start position:0% +was immediately adopted they were +already using it in 1899 as a form of + + align:start position:0% +already using it in 1899 as a form of + + + align:start position:0% +already using it in 1899 as a form of +treatment for + + align:start position:0% +treatment for + + + align:start position:0% +treatment for +cancer very interesting took over so + + align:start position:0% +cancer very interesting took over so + + + align:start position:0% +cancer very interesting took over so +what's the relative physics what's going + + align:start position:0% +what's the relative physics what's going + + + align:start position:0% +what's the relative physics what's going +on here so where do we have to go I said + + align:start position:0% +on here so where do we have to go I said + + + align:start position:0% +on here so where do we have to go I said +we have to look at the anode because + + align:start position:0% +we have to look at the anode because + + + align:start position:0% +we have to look at the anode because +that's where the electrons are crashing + + align:start position:0% +that's where the electrons are crashing + + + align:start position:0% +that's where the electrons are crashing +into that's the site of the Collision + + align:start position:0% +into that's the site of the Collision + + + align:start position:0% +into that's the site of the Collision +isn't it something's happening at that + + align:start position:0% +isn't it something's happening at that + + + align:start position:0% +isn't it something's happening at that +anode so let's look inside the anode and + + align:start position:0% +anode so let's look inside the anode and + + + align:start position:0% +anode so let's look inside the anode and +suppose it's copper what could we say + + align:start position:0% +suppose it's copper what could we say + + + align:start position:0% +suppose it's copper what could we say +about + + align:start position:0% +about + + + align:start position:0% +about +it the + + align:start position:0% +it the + + + align:start position:0% +it the +anode this is where the electron + + align:start position:0% +anode this is where the electron + + + align:start position:0% +anode this is where the electron +Collision that's the Maximum Impact + + align:start position:0% +Collision that's the Maximum Impact + + + align:start position:0% +Collision that's the Maximum Impact +isn't it so let's just see what might be + + align:start position:0% +isn't it so let's just see what might be + + + align:start position:0% +isn't it so let's just see what might be +going on I want to show you the power of + + align:start position:0% +going on I want to show you the power of + + + align:start position:0% +going on I want to show you the power of +estimation okay um how far how far down + + align:start position:0% +estimation okay um how far how far down + + + align:start position:0% +estimation okay um how far how far down +I've shown you that with nitrogen at + + align:start position:0% +I've shown you that with nitrogen at + + + align:start position:0% +I've shown you that with nitrogen at +668 uh electron volts to get to the + + align:start position:0% +668 uh electron volts to get to the + + + align:start position:0% +668 uh electron volts to get to the +inner shell electrons what about in The + + align:start position:0% +inner shell electrons what about in The + + + align:start position:0% +inner shell electrons what about in The +Case of the anode well um what's going + + align:start position:0% +Case of the anode well um what's going + + + align:start position:0% +Case of the anode well um what's going +on there well I can say what's the + + align:start position:0% +on there well I can say what's the + + + align:start position:0% +on there well I can say what's the +energy of the 1s electron in Copper 28 + + align:start position:0% +energy of the 1s electron in Copper 28 + + + align:start position:0% +energy of the 1s electron in Copper 28 +plus that's a one electron system okay + + align:start position:0% +plus that's a one electron system okay + + + align:start position:0% +plus that's a one electron system okay +and you know that in real copper with + + align:start position:0% +and you know that in real copper with + + + align:start position:0% +and you know that in real copper with +all of its electrons this value is going + + align:start position:0% +all of its electrons this value is going + + + align:start position:0% +all of its electrons this value is going +to be an overestimate because the + + align:start position:0% +to be an overestimate because the + + + align:start position:0% +to be an overestimate because the +presence of all the other electrons is + + align:start position:0% +presence of all the other electrons is + + + align:start position:0% +presence of all the other electrons is +going to sap some of the protonic uh + + align:start position:0% +going to sap some of the protonic uh + + + align:start position:0% +going to sap some of the protonic uh +culic Force so this will be a an upper + + align:start position:0% +culic Force so this will be a an upper + + + align:start position:0% +culic Force so this will be a an upper +bound of what that energy could be we + + align:start position:0% +bound of what that energy could be we + + + align:start position:0% +bound of what that energy could be we +know that's simply equal to the energy + + align:start position:0% +know that's simply equal to the energy + + + align:start position:0% +know that's simply equal to the energy +of the 1s in hydrogen right times + + align:start position:0% +of the 1s in hydrogen right times + + + align:start position:0% +of the 1s in hydrogen right times +z^2 so if I take 13.6 electron volts + + align:start position:0% +z^2 so if I take 13.6 electron volts + + + align:start position:0% +z^2 so if I take 13.6 electron volts +time + + align:start position:0% +time + + + align:start position:0% +time +29 squared I get + + align:start position:0% + + + + align:start position:0% + +114,000 electron volts which is still + + align:start position:0% +114,000 electron volts which is still + + + align:start position:0% +114,000 electron volts which is still +less than the 35,000 + + align:start position:0% +less than the 35,000 + + + align:start position:0% +less than the 35,000 +electron volts that renen had so renen + + align:start position:0% +electron volts that renen had so renen + + + align:start position:0% +electron volts that renen had so renen +is running a a huge bowling alley here + + align:start position:0% +is running a a huge bowling alley here + + + align:start position:0% +is running a a huge bowling alley here +he's able to knock out 1s electrons from + + align:start position:0% +he's able to knock out 1s electrons from + + + align:start position:0% +he's able to knock out 1s electrons from +copper and what happens when you knock + + align:start position:0% +copper and what happens when you knock + + + align:start position:0% +copper and what happens when you knock +out electrons intershell electrons + + align:start position:0% +out electrons intershell electrons + + + align:start position:0% +out electrons intershell electrons +what's the next thing that + + align:start position:0% +what's the next thing that + + + align:start position:0% +what's the next thing that +happens now let's look at an energy + + align:start position:0% +happens now let's look at an energy + + + align:start position:0% +happens now let's look at an energy +level diagram so let's let's suppose + + align:start position:0% +level diagram so let's let's suppose + + + align:start position:0% +level diagram so let's let's suppose +this is a the anode so this is the anode + + align:start position:0% +this is a the anode so this is the anode + + + align:start position:0% +this is a the anode so this is the anode +in the gas tube it's energy level + + align:start position:0% +in the gas tube it's energy level + + + align:start position:0% +in the gas tube it's energy level +diagram so this is going to be n equal + + align:start position:0% +diagram so this is going to be n equal + + + align:start position:0% +diagram so this is going to be n equal +infinity and we'll just do a few of them + + align:start position:0% +infinity and we'll just do a few of them + + + align:start position:0% +infinity and we'll just do a few of them +so this is n = 4 n = 3 Nal 2 and n + + align:start position:0% +so this is n = 4 n = 3 Nal 2 and n + + + align:start position:0% +so this is n = 4 n = 3 Nal 2 and n +equals 1 not to scale I'm trying to show + + align:start position:0% +equals 1 not to scale I'm trying to show + + + align:start position:0% +equals 1 not to scale I'm trying to show +that they're a little bit farther apart + + align:start position:0% +that they're a little bit farther apart + + + align:start position:0% +that they're a little bit farther apart +as you go lower and lower and so this is + + align:start position:0% +as you go lower and lower and so this is + + + align:start position:0% +as you go lower and lower and so this is +ground state energy E1 this is Nal 2 + + align:start position:0% +ground state energy E1 this is Nal 2 + + + align:start position:0% +ground state energy E1 this is Nal 2 +shell Nal 3 shell Nal 4 shell and out + + align:start position:0% +shell Nal 3 shell Nal 4 shell and out + + + align:start position:0% +shell Nal 3 shell Nal 4 shell and out +here it's zero isn't it and so what do I + + align:start position:0% +here it's zero isn't it and so what do I + + + align:start position:0% +here it's zero isn't it and so what do I +have I've got some instent electron that + + align:start position:0% +have I've got some instent electron that + + + align:start position:0% +have I've got some instent electron that +comes zooming in here zooming in here + + align:start position:0% +comes zooming in here zooming in here + + + align:start position:0% +comes zooming in here zooming in here +this is + + align:start position:0% +this is + + + align:start position:0% +this is +incident this is the one that's been + + align:start position:0% +incident this is the one that's been + + + align:start position:0% +incident this is the one that's been +accelerated right so the energy of this + + align:start position:0% +accelerated right so the energy of this + + + align:start position:0% +accelerated right so the energy of this +electron it's all kinetic and that's + + align:start position:0% +electron it's all kinetic and that's + + + align:start position:0% +electron it's all kinetic and that's +equal to product of the charge on the + + align:start position:0% +equal to product of the charge on the + + + align:start position:0% +equal to product of the charge on the +electron which is Elemental e times a + + align:start position:0% +electron which is Elemental e times a + + + align:start position:0% +electron which is Elemental e times a +plate voltage which is 35,000 volts + + align:start position:0% +plate voltage which is 35,000 volts + + + align:start position:0% +plate voltage which is 35,000 volts +that's how I get 35,000 electron volts + + align:start position:0% +that's how I get 35,000 electron volts + + + align:start position:0% +that's how I get 35,000 electron volts +is the energy and it can come in and + + align:start position:0% +is the energy and it can come in and + + + align:start position:0% +is the energy and it can come in and +we've just showing that it's got enough + + align:start position:0% +we've just showing that it's got enough + + + align:start position:0% +we've just showing that it's got enough +energy that it can even knock out an + + align:start position:0% +energy that it can even knock out an + + + align:start position:0% +energy that it can even knock out an +inner shell + + align:start position:0% +inner shell + + + align:start position:0% +inner shell +electron it can even dislodge an inner + + align:start position:0% +electron it can even dislodge an inner + + + align:start position:0% +electron it can even dislodge an inner +shell electron so let's see what would + + align:start position:0% +shell electron so let's see what would + + + align:start position:0% +shell electron so let's see what would +happen if that were the case it + + align:start position:0% +happen if that were the case it + + + align:start position:0% +happen if that were the case it +dislodges an inner shell electron what's + + align:start position:0% +dislodges an inner shell electron what's + + + align:start position:0% +dislodges an inner shell electron what's +the next thing well I've got a vacancy + + align:start position:0% +the next thing well I've got a vacancy + + + align:start position:0% +the next thing well I've got a vacancy +down here so what will happen well + + align:start position:0% +down here so what will happen well + + + align:start position:0% +down here so what will happen well +electron will fall from n equals 2 to n + + align:start position:0% +electron will fall from n equals 2 to n + + + align:start position:0% +electron will fall from n equals 2 to n +equals 1 and when it does + + align:start position:0% +equals 1 and when it does + + + align:start position:0% +equals 1 and when it does +so it gives off radiation it gives off + + align:start position:0% + + + + align:start position:0% + +radiation well if it falls from n equals + + align:start position:0% +radiation well if it falls from n equals + + + align:start position:0% +radiation well if it falls from n equals +2 Nal 1 there's a slim chance it might + + align:start position:0% +2 Nal 1 there's a slim chance it might + + + align:start position:0% +2 Nal 1 there's a slim chance it might +even fall from Nal 3 to Nal 1 or maybe + + align:start position:0% +even fall from Nal 3 to Nal 1 or maybe + + + align:start position:0% +even fall from Nal 3 to Nal 1 or maybe +even Nal 4 to Nal 1 well heck if it can + + align:start position:0% +even Nal 4 to Nal 1 well heck if it can + + + align:start position:0% +even Nal 4 to Nal 1 well heck if it can +go from two to one there's a vacancy in + + align:start position:0% +go from two to one there's a vacancy in + + + align:start position:0% +go from two to one there's a vacancy in +two so I might get 3 to two I might get + + align:start position:0% +two so I might get 3 to two I might get + + + align:start position:0% +two so I might get 3 to two I might get +four to two and you get the picture you + + align:start position:0% +four to two and you get the picture you + + + align:start position:0% +four to two and you get the picture you +get a whole Cascade here you get a whole + + align:start position:0% +get a whole Cascade here you get a whole + + + align:start position:0% +get a whole Cascade here you get a whole +Cascade each one of these gives off + + align:start position:0% +Cascade each one of these gives off + + + align:start position:0% +Cascade each one of these gives off +photons Photon emissions so you have you + + align:start position:0% +photons Photon emissions so you have you + + + align:start position:0% +photons Photon emissions so you have you +have + + align:start position:0% +have + + + align:start position:0% +have +expulsion expulsion + + align:start position:0% +expulsion expulsion + + + align:start position:0% +expulsion expulsion +of K + + align:start position:0% +of K + + + align:start position:0% +of K +shell all of the electrons but you can + + align:start position:0% +shell all of the electrons but you can + + + align:start position:0% +shell all of the electrons but you can +go all the way down to the kshell kshell + + align:start position:0% +go all the way down to the kshell kshell + + + align:start position:0% +go all the way down to the kshell kshell +electrons and then + + align:start position:0% + + + + align:start position:0% + +Cascade and accompanied by photo + + align:start position:0% +Cascade and accompanied by photo + + + align:start position:0% +Cascade and accompanied by photo +emission + + align:start position:0% +emission + + + align:start position:0% +emission +photoemission the difference is that + + align:start position:0% +photoemission the difference is that + + + align:start position:0% +photoemission the difference is that +instead of being in the visible or the + + align:start position:0% +instead of being in the visible or the + + + align:start position:0% +instead of being in the visible or the +infrared these energy levels are so + + align:start position:0% +infrared these energy levels are so + + + align:start position:0% +infrared these energy levels are so +so tightly bounded that this is in the X + + align:start position:0% +so tightly bounded that this is in the X + + + align:start position:0% +so tightly bounded that this is in the X +region of the spectrum this is in the X + + align:start position:0% +region of the spectrum this is in the X + + + align:start position:0% +region of the spectrum this is in the X +region of the spectrum and we have + + align:start position:0% +region of the spectrum and we have + + + align:start position:0% +region of the spectrum and we have +labels for these different uh for these + + align:start position:0% +labels for these different uh for these + + + align:start position:0% +labels for these different uh for these +different uh photons um and first of all + + align:start position:0% +different uh photons um and first of all + + + align:start position:0% +different uh photons um and first of all +you know that the spectroscopists don't + + align:start position:0% +you know that the spectroscopists don't + + + align:start position:0% +you know that the spectroscopists don't +like the numbers this is the chemist + + align:start position:0% +like the numbers this is the chemist + + + align:start position:0% +like the numbers this is the chemist +notation Nal 1 Nal 2 Nal 3 Nal 4 the + + align:start position:0% +notation Nal 1 Nal 2 Nal 3 Nal 4 the + + + align:start position:0% +notation Nal 1 Nal 2 Nal 3 Nal 4 the +spectroscopists call the ground state + + align:start position:0% +spectroscopists call the ground state + + + align:start position:0% +spectroscopists call the ground state +kshell this is mshell this is n shell + + align:start position:0% +kshell this is mshell this is n shell + + + align:start position:0% +kshell this is mshell this is n shell +okay I left out a letter in the alphabet + + align:start position:0% +okay I left out a letter in the alphabet + + + align:start position:0% +okay I left out a letter in the alphabet +k l L shell mshell n shell so we can + + align:start position:0% +k l L shell mshell n shell so we can + + + align:start position:0% +k l L shell mshell n shell so we can +label this as a photon that came from a + + align:start position:0% +label this as a photon that came from a + + + align:start position:0% +label this as a photon that came from a +Cascade down to the K shell and to + + align:start position:0% +Cascade down to the K shell and to + + + align:start position:0% +Cascade down to the K shell and to +distinguish this kshell electron from + + align:start position:0% +distinguish this kshell electron from + + + align:start position:0% +distinguish this kshell electron from +the kshell electron involving a + + align:start position:0% +the kshell electron involving a + + + align:start position:0% +the kshell electron involving a +transition from Nal 3 down to nals 1 we + + align:start position:0% +transition from Nal 3 down to nals 1 we + + + align:start position:0% +transition from Nal 3 down to nals 1 we +have a + + align:start position:0% +have a + + + align:start position:0% +have a +second indicator and that's the + + align:start position:0% +second indicator and that's the + + + align:start position:0% +second indicator and that's the +subscript Alpha so this means the + + align:start position:0% +subscript Alpha so this means the + + + align:start position:0% +subscript Alpha so this means the +Cascade + + align:start position:0% +Cascade + + + align:start position:0% +Cascade +Cascade down to + + align:start position:0% +Cascade down to + + + align:start position:0% +Cascade down to +kshell and the alpha + + align:start position:0% +kshell and the alpha + + + align:start position:0% +kshell and the alpha +represents how far the electron traveled + + align:start position:0% +represents how far the electron traveled + + + align:start position:0% +represents how far the electron traveled +okay + + align:start position:0% +okay + + + align:start position:0% +okay +from one shell away so that means from + + align:start position:0% +from one shell away so that means from + + + align:start position:0% +from one shell away so that means from +Nal 2 to Nal 1 this is a + + align:start position:0% +Nal 2 to Nal 1 this is a + + + align:start position:0% +Nal 2 to Nal 1 this is a +k beta + + align:start position:0% +k beta + + + align:start position:0% +k beta +Photon this is a k gamma photon so this + + align:start position:0% +Photon this is a k gamma photon so this + + + align:start position:0% +Photon this is a k gamma photon so this +is like a Lyman series all right this is + + align:start position:0% +is like a Lyman series all right this is + + + align:start position:0% +is like a Lyman series all right this is +like a Balmer series because it always + + align:start position:0% +like a Balmer series because it always + + + align:start position:0% +like a Balmer series because it always +ends at nals 2 Nal 3 to Nal 2 gives us a + + align:start position:0% +ends at nals 2 Nal 3 to Nal 2 gives us a + + + align:start position:0% +ends at nals 2 Nal 3 to Nal 2 gives us a +photon and that photon is going to be + + align:start position:0% +photon and that photon is going to be + + + align:start position:0% +photon and that photon is going to be +called L Alpha Nal 4 to Nal 2 will give + + align:start position:0% +called L Alpha Nal 4 to Nal 2 will give + + + align:start position:0% +called L Alpha Nal 4 to Nal 2 will give +us a photon and that's going to be + + align:start position:0% +us a photon and that's going to be + + + align:start position:0% +us a photon and that's going to be +called L beta so I'm going to get a + + align:start position:0% +called L beta so I'm going to get a + + + align:start position:0% +called L beta so I'm going to get a +whole Spectrum I'm going to get a whole + + align:start position:0% +whole Spectrum I'm going to get a whole + + + align:start position:0% +whole Spectrum I'm going to get a whole +Spectrum let's take a look at what that + + align:start position:0% +Spectrum let's take a look at what that + + + align:start position:0% +Spectrum let's take a look at what that +Spectrum might look like uh I could + + align:start position:0% +Spectrum might look like uh I could + + + align:start position:0% +Spectrum might look like uh I could +calculate any one of these I could say + + align:start position:0% +calculate any one of these I could say + + + align:start position:0% +calculate any one of these I could say +Lambda of copper K Alpha would equal + + align:start position:0% +Lambda of copper K Alpha would equal + + + align:start position:0% +Lambda of copper K Alpha would equal +what it's the same as you've seen before + + align:start position:0% +what it's the same as you've seen before + + + align:start position:0% +what it's the same as you've seen before +HC over what the + + align:start position:0% +HC over what the + + + align:start position:0% +HC over what the +energy of Nal 2 shell to energy of n + + align:start position:0% +energy of Nal 2 shell to energy of n + + + align:start position:0% +energy of Nal 2 shell to energy of n +equals 1 shell so what can we do we can + + align:start position:0% +equals 1 shell so what can we do we can + + + align:start position:0% +equals 1 shell so what can we do we can +measure this we know H and C we can + + align:start position:0% +measure this we know H and C we can + + + align:start position:0% +measure this we know H and C we can +calculate what those energy levels are + + align:start position:0% +calculate what those energy levels are + + + align:start position:0% +calculate what those energy levels are +right so let's plot this out I could + + align:start position:0% +right so let's plot this out I could + + + align:start position:0% +right so let's plot this out I could +make a plot of + + align:start position:0% + + + + align:start position:0% + +wavelength intensity and I will get an + + align:start position:0% +wavelength intensity and I will get an + + + align:start position:0% +wavelength intensity and I will get an +entire spectrum of lines I'll have first + + align:start position:0% +entire spectrum of lines I'll have first + + + align:start position:0% +entire spectrum of lines I'll have first +the this is high wavelength so that + + align:start position:0% +the this is high wavelength so that + + + align:start position:0% +the this is high wavelength so that +means energy is increasing from right to + + align:start position:0% +means energy is increasing from right to + + + align:start position:0% +means energy is increasing from right to +left so the highest energy is over here + + align:start position:0% +left so the highest energy is over here + + + align:start position:0% +left so the highest energy is over here +so what's the highest energy up there + + align:start position:0% +so what's the highest energy up there + + + align:start position:0% +so what's the highest energy up there +the highest energy looks like Nal 4 down + + align:start position:0% +the highest energy looks like Nal 4 down + + + align:start position:0% +the highest energy looks like Nal 4 down +to Nal 1 so that's going to be over here + + align:start position:0% +to Nal 1 so that's going to be over here + + + align:start position:0% +to Nal 1 so that's going to be over here +so this could be K gamma then K beta + + align:start position:0% + + + + align:start position:0% + +okay Alpha then the L lines are 3:2 4:2 + + align:start position:0% +okay Alpha then the L lines are 3:2 4:2 + + + align:start position:0% +okay Alpha then the L lines are 3:2 4:2 +so they're over here so this is L Alpha + + align:start position:0% +so they're over here so this is L Alpha + + + align:start position:0% +so they're over here so this is L Alpha +L beta and so on and these different + + align:start position:0% +L beta and so on and these different + + + align:start position:0% +L beta and so on and these different +wavelengths are associated with + + align:start position:0% +wavelengths are associated with + + + align:start position:0% +wavelengths are associated with +different + + align:start position:0% +different + + + align:start position:0% +different +energies and these different energies + + align:start position:0% +energies and these different energies + + + align:start position:0% +energies and these different energies +are associated with what they're + + align:start position:0% +are associated with what they're + + + align:start position:0% +are associated with what they're +associated with The + + align:start position:0% +associated with The + + + align:start position:0% +associated with The +Binding inside the atom inside the + + align:start position:0% +Binding inside the atom inside the + + + align:start position:0% +Binding inside the atom inside the +target + + align:start position:0% +target + + + align:start position:0% +target +so every target has its own number of + + align:start position:0% +so every target has its own number of + + + align:start position:0% +so every target has its own number of +protons its own number of electrons so + + align:start position:0% +protons its own number of electrons so + + + align:start position:0% +protons its own number of electrons so +this set of lines is characteristic of + + align:start position:0% +this set of lines is characteristic of + + + align:start position:0% +this set of lines is characteristic of +the + + align:start position:0% +the + + + align:start position:0% +the +target it's characteristic of the + + align:start position:0% +target it's characteristic of the + + + align:start position:0% +target it's characteristic of the +Target and I had to do a whole year of + + align:start position:0% +Target and I had to do a whole year of + + + align:start position:0% +Target and I had to do a whole year of +X-ray crystallography as a junior back + + align:start position:0% +X-ray crystallography as a junior back + + + align:start position:0% +X-ray crystallography as a junior back +at the University of Toronto we used + + align:start position:0% +at the University of Toronto we used + + + align:start position:0% +at the University of Toronto we used +copper as the target I will + + align:start position:0% +copper as the target I will + + + align:start position:0% +copper as the target I will +know on my deathbed that the wavelength + + align:start position:0% +know on my deathbed that the wavelength + + + align:start position:0% +know on my deathbed that the wavelength +of copper K Alpha is 1.54 + + align:start position:0% +of copper K Alpha is 1.54 + + + align:start position:0% +of copper K Alpha is 1.54 +18 angstroms okay so if I walk into the + + align:start position:0% +18 angstroms okay so if I walk into the + + + align:start position:0% +18 angstroms okay so if I walk into the +room and I see 1.54 one8 angstroms + + align:start position:0% +room and I see 1.54 one8 angstroms + + + align:start position:0% +room and I see 1.54 one8 angstroms +that's + + align:start position:0% +that's + + + align:start position:0% +that's +copper it comes from copper and any + + align:start position:0% +copper it comes from copper and any + + + align:start position:0% +copper it comes from copper and any +other element is going to give me a + + align:start position:0% +other element is going to give me a + + + align:start position:0% +other element is going to give me a +different set of lines so what I'm + + align:start position:0% +different set of lines so what I'm + + + align:start position:0% +different set of lines so what I'm +learning here is I have a way of + + align:start position:0% +learning here is I have a way of + + + align:start position:0% +learning here is I have a way of +identifying elements so this is now + + align:start position:0% +identifying elements so this is now + + + align:start position:0% +identifying elements so this is now +turning into something that could be a + + align:start position:0% +turning into something that could be a + + + align:start position:0% +turning into something that could be a +technique of chemical analysis and we'll + + align:start position:0% +technique of chemical analysis and we'll + + + align:start position:0% +technique of chemical analysis and we'll +return next day to see what else we can + + align:start position:0% +return next day to see what else we can + + + align:start position:0% +return next day to see what else we can +do with it uh so so uh just for the last + + align:start position:0% +do with it uh so so uh just for the last + + + align:start position:0% +do with it uh so so uh just for the last +five minutes I'm going to show you a + + align:start position:0% +five minutes I'm going to show you a + + + align:start position:0% +five minutes I'm going to show you a +little bit more about uh uh renen and + + align:start position:0% +little bit more about uh uh renen and + + + align:start position:0% +little bit more about uh uh renen and +his Discovery but I wanted to uh pay uh + + align:start position:0% +his Discovery but I wanted to uh pay uh + + + align:start position:0% +his Discovery but I wanted to uh pay uh +um just uh draw attention to our winner + + align:start position:0% +um just uh draw attention to our winner + + + align:start position:0% +um just uh draw attention to our winner +from Friday Who U was unable to attend + + align:start position:0% +from Friday Who U was unable to attend + + + align:start position:0% +from Friday Who U was unable to attend +the lecture and uh so I want to ask uh n + + align:start position:0% +the lecture and uh so I want to ask uh n + + + align:start position:0% +the lecture and uh so I want to ask uh n +Gabriel to stand and uh accept her uh + + align:start position:0% +Gabriel to stand and uh accept her uh + + + align:start position:0% +Gabriel to stand and uh accept her uh +acknowledgement for the fine job she did + + align:start position:0% +acknowledgement for the fine job she did + + + align:start position:0% +acknowledgement for the fine job she did +on the actinide uh thing and she's + + align:start position:0% +on the actinide uh thing and she's + + + align:start position:0% +on the actinide uh thing and she's +wearing her scarf why don't you come + + align:start position:0% +wearing her scarf why don't you come + + + align:start position:0% +wearing her scarf why don't you come +down and people can see you wearing the + + align:start position:0% +down and people can see you wearing the + + + align:start position:0% +down and people can see you wearing the +really super hot American Chemical + + align:start position:0% +really super hot American Chemical + + + align:start position:0% +really super hot American Chemical +Society + + align:start position:0% + + + + align:start position:0% + +scarf thank + + align:start position:0% +scarf thank + + + align:start position:0% +scarf thank +you good good now here's the dark and + + align:start position:0% +you good good now here's the dark and + + + align:start position:0% +you good good now here's the dark and +stormy night uh the following morning + + align:start position:0% +stormy night uh the following morning + + + align:start position:0% +stormy night uh the following morning +it's sunny this is Ren's laboratory on + + align:start position:0% +it's sunny this is Ren's laboratory on + + + align:start position:0% +it's sunny this is Ren's laboratory on +the second floor of his flat in bburg + + align:start position:0% +the second floor of his flat in bburg + + + align:start position:0% +the second floor of his flat in bburg +it's a museum today and you can see the + + align:start position:0% +it's a museum today and you can see the + + + align:start position:0% +it's a museum today and you can see the +tubes and the the lead wires going down + + align:start position:0% +tubes and the the lead wires going down + + + align:start position:0% +tubes and the the lead wires going down +to the basement and so on now hold it I + + align:start position:0% +to the basement and so on now hold it I + + + align:start position:0% +to the basement and so on now hold it I +don't I don't want a lot of noise you + + align:start position:0% +don't I don't want a lot of noise you + + + align:start position:0% +don't I don't want a lot of noise you +know + + align:start position:0% +know + + + align:start position:0% +know +just all right this is the first + + align:start position:0% +just all right this is the first + + + align:start position:0% +just all right this is the first +radiograph ever this is rin's wife + + align:start position:0% +radiograph ever this is rin's wife + + + align:start position:0% +radiograph ever this is rin's wife +Bera yes you know he noticed that there + + align:start position:0% +Bera yes you know he noticed that there + + + align:start position:0% +Bera yes you know he noticed that there +was a shadow with the lead but renin I + + align:start position:0% +was a shadow with the lead but renin I + + + align:start position:0% +was a shadow with the lead but renin I +mean he was smart I mean he was he was + + align:start position:0% +mean he was smart I mean he was he was + + + align:start position:0% +mean he was smart I mean he was he was +he had to share the glory so he said + + align:start position:0% +he had to share the glory so he said + + + align:start position:0% +he had to share the glory so he said +honey uh would you mind coming upstairs + + align:start position:0% +honey uh would you mind coming upstairs + + + align:start position:0% +honey uh would you mind coming upstairs +I'd like to take your picture and so + + align:start position:0% +I'd like to take your picture and so + + + align:start position:0% +I'd like to take your picture and so +Bertha put her hand in the path of the + + align:start position:0% +Bertha put her hand in the path of the + + + align:start position:0% +Bertha put her hand in the path of the +X-ray and for 15 full minutes uh waited + + align:start position:0% +X-ray and for 15 full minutes uh waited + + + align:start position:0% +X-ray and for 15 full minutes uh waited +while those x-rays uh went through you + + align:start position:0% +while those x-rays uh went through you + + + align:start position:0% +while those x-rays uh went through you +can see the ring on her finger and so on + + align:start position:0% +can see the ring on her finger and so on + + + align:start position:0% +can see the ring on her finger and so on +she endured in that 15 minutes uh + + align:start position:0% +she endured in that 15 minutes uh + + + align:start position:0% +she endured in that 15 minutes uh +greater than a lifetime dose of what we + + align:start position:0% +greater than a lifetime dose of what we + + + align:start position:0% +greater than a lifetime dose of what we +would consider safe today U people just + + align:start position:0% +would consider safe today U people just + + + align:start position:0% +would consider safe today U people just +didn't know anyways um this gave birth + + align:start position:0% +didn't know anyways um this gave birth + + + align:start position:0% +didn't know anyways um this gave birth +to Medical radiography and I would uh + + align:start position:0% +to Medical radiography and I would uh + + + align:start position:0% +to Medical radiography and I would uh +just out of curiosity like to know is is + + align:start position:0% +just out of curiosity like to know is is + + + align:start position:0% +just out of curiosity like to know is is +there there anybody in this room who's + + align:start position:0% +there there anybody in this room who's + + + align:start position:0% +there there anybody in this room who's +never had a medical or dental + + align:start position:0% + + + + align:start position:0% + +x-ray I see a very few I see a few hands + + align:start position:0% +x-ray I see a very few I see a few hands + + + align:start position:0% +x-ray I see a very few I see a few hands +few hands to you I say congratulations + + align:start position:0% +few hands to you I say congratulations + + + align:start position:0% +few hands to you I say congratulations +and I hope you keep up the good work um + + align:start position:0% +and I hope you keep up the good work um + + + align:start position:0% +and I hope you keep up the good work um +okay here's a second thing so we have we + + align:start position:0% +okay here's a second thing so we have we + + + align:start position:0% +okay here's a second thing so we have we +have radiography that came out of Ren's + + align:start position:0% +have radiography that came out of Ren's + + + align:start position:0% +have radiography that came out of Ren's +Discovery renen had a beam um a torsion + + align:start position:0% +Discovery renen had a beam um a torsion + + + align:start position:0% +Discovery renen had a beam um a torsion +balance okay you know like the Justice + + align:start position:0% +balance okay you know like the Justice + + + align:start position:0% +balance okay you know like the Justice +she's got the two scales so the one + + align:start position:0% +she's got the two scales so the one + + + align:start position:0% +she's got the two scales so the one +scale you put the unknown in the other + + align:start position:0% +scale you put the unknown in the other + + + align:start position:0% +scale you put the unknown in the other +scale you put the calibrated Mass so he + + align:start position:0% +scale you put the calibrated Mass so he + + + align:start position:0% +scale you put the calibrated Mass so he +had a set of brass weights here in a + + align:start position:0% +had a set of brass weights here in a + + + align:start position:0% +had a set of brass weights here in a +wooden box and he closed the wooden box + + align:start position:0% +wooden box and he closed the wooden box + + + align:start position:0% +wooden box and he closed the wooden box +and he irradiated the box with the + + align:start position:0% +and he irradiated the box with the + + + align:start position:0% +and he irradiated the box with the +x-rays and took this + + align:start position:0% +x-rays and took this + + + align:start position:0% +x-rays and took this +Photograph and what do you see you see + + align:start position:0% +Photograph and what do you see you see + + + align:start position:0% +Photograph and what do you see you see +that different materials have different + + align:start position:0% +that different materials have different + + + align:start position:0% +that different materials have different +electron + + align:start position:0% +electron + + + align:start position:0% +electron +densities and therefore the wood is + + align:start position:0% +densities and therefore the wood is + + + align:start position:0% +densities and therefore the wood is +transparent more or less to x-rays + + align:start position:0% +transparent more or less to x-rays + + + align:start position:0% +transparent more or less to x-rays +whereas the brass is less so so you have + + align:start position:0% +whereas the brass is less so so you have + + + align:start position:0% +whereas the brass is less so so you have +a differentiation you know the way we + + align:start position:0% +a differentiation you know the way we + + + align:start position:0% +a differentiation you know the way we +see things is by + + align:start position:0% +see things is by + + + align:start position:0% +see things is by +differentiation so here you have a + + align:start position:0% +differentiation so here you have a + + + align:start position:0% +differentiation so here you have a +differentiation so he could identify + + align:start position:0% +differentiation so he could identify + + + align:start position:0% +differentiation so he could identify +what was in the box when the box was + + align:start position:0% +what was in the box when the box was + + + align:start position:0% +what was in the box when the box was +closed so that gives rise + + align:start position:0% +closed so that gives rise + + + align:start position:0% +closed so that gives rise +to security technology every time you go + + align:start position:0% +to security technology every time you go + + + align:start position:0% +to security technology every time you go +to the airport you are subjected to this + + align:start position:0% +to the airport you are subjected to this + + + align:start position:0% +to the airport you are subjected to this +and it started with + + align:start position:0% + + + + align:start position:0% + +renen renen also had a + + align:start position:0% +renen renen also had a + + + align:start position:0% +renen renen also had a +gun it was a musket come on he wasn't + + align:start position:0% +gun it was a musket come on he wasn't + + + align:start position:0% +gun it was a musket come on he wasn't +wasn't holding up convenience stores + + align:start position:0% +wasn't holding up convenience stores + + + align:start position:0% +wasn't holding up convenience stores +what do you laughing you know he had a + + align:start position:0% +what do you laughing you know he had a + + + align:start position:0% +what do you laughing you know he had a +gun right he went hunting so he he took + + align:start position:0% +gun right he went hunting so he he took + + + align:start position:0% +gun right he went hunting so he he took +an X Raph of his + + align:start position:0% +an X Raph of his + + + align:start position:0% +an X Raph of his +gun and this is used today it gives + + align:start position:0% +gun and this is used today it gives + + + align:start position:0% +gun and this is used today it gives +birth to the technology of failure + + align:start position:0% +birth to the technology of failure + + + align:start position:0% +birth to the technology of failure +analysis in fact there are certain um + + align:start position:0% +analysis in fact there are certain um + + + align:start position:0% +analysis in fact there are certain um +types of + + align:start position:0% +types of + + + align:start position:0% +types of +weld typically involving very dangerous + + align:start position:0% +weld typically involving very dangerous + + + align:start position:0% +weld typically involving very dangerous +uh circumstances such as pressure + + align:start position:0% +uh circumstances such as pressure + + + align:start position:0% +uh circumstances such as pressure +vessels that are going to contain steam + + align:start position:0% +vessels that are going to contain steam + + + align:start position:0% +vessels that are going to contain steam +at very very high pressures the code is + + align:start position:0% +at very very high pressures the code is + + + align:start position:0% +at very very high pressures the code is +is that every inch of the welded seam + + align:start position:0% +is that every inch of the welded seam + + + align:start position:0% +is that every inch of the welded seam +must be inspected by X radiation in + + align:start position:0% +must be inspected by X radiation in + + + align:start position:0% +must be inspected by X radiation in +order to find what internal cracks + + align:start position:0% +order to find what internal cracks + + + align:start position:0% +order to find what internal cracks +because if there's a crack there's a + + align:start position:0% +because if there's a crack there's a + + + align:start position:0% +because if there's a crack there's a +difference in in electron density and so + + align:start position:0% +difference in in electron density and so + + + align:start position:0% +difference in in electron density and so +you'll see contrast in the X-ray + + align:start position:0% +you'll see contrast in the X-ray + + + align:start position:0% +you'll see contrast in the X-ray +photograph so from that experiment come + + align:start position:0% +photograph so from that experiment come + + + align:start position:0% +photograph so from that experiment come +three Technologies three + + align:start position:0% +three Technologies three + + + align:start position:0% +three Technologies three +Technologies and for his work + + align:start position:0% +Technologies and for his work + + + align:start position:0% +Technologies and for his work +renen was the recipient of the very + + align:start position:0% +renen was the recipient of the very + + + align:start position:0% +renen was the recipient of the very +first Nobel Prize in physics it was + + align:start position:0% +first Nobel Prize in physics it was + + + align:start position:0% +first Nobel Prize in physics it was +awarded in 1901 and he was the unanimous + + align:start position:0% +awarded in 1901 and he was the unanimous + + + align:start position:0% +awarded in 1901 and he was the unanimous +choice of the world physics Community + + align:start position:0% +choice of the world physics Community + + + align:start position:0% +choice of the world physics Community +for the for what he had done and you're + + align:start position:0% +for the for what he had done and you're + + + align:start position:0% +for the for what he had done and you're +going to see next day more that uh the + + align:start position:0% +going to see next day more that uh the + + + align:start position:0% +going to see next day more that uh the +the discovery of x-rays enabl but one + + align:start position:0% +the discovery of x-rays enabl but one + + + align:start position:0% +the discovery of x-rays enabl but one +last + + align:start position:0% +last + + + align:start position:0% +last +thing what a what a fine human being he + + align:start position:0% +thing what a what a fine human being he + + + align:start position:0% +thing what a what a fine human being he +was you know what he did with his + + align:start position:0% +was you know what he did with his + + + align:start position:0% +was you know what he did with his +winnings he donated them to the + + align:start position:0% +winnings he donated them to the + + + align:start position:0% +winnings he donated them to the +University of wburg to be made an + + align:start position:0% +University of wburg to be made an + + + align:start position:0% +University of wburg to be made an +endowment for student scholarships and + + align:start position:0% +endowment for student scholarships and + + + align:start position:0% +endowment for student scholarships and +to this day physics students at the + + align:start position:0% +to this day physics students at the + + + align:start position:0% +to this day physics students at the +University of verburg are recipience of + + align:start position:0% +University of verburg are recipience of + + + align:start position:0% +University of verburg are recipience of +scholarships that were endowed by renen + + align:start position:0% +scholarships that were endowed by renen + + + align:start position:0% +scholarships that were endowed by renen +with his Nobel Prize winnings in 1901 + + align:start position:0% +with his Nobel Prize winnings in 1901 + + + align:start position:0% +with his Nobel Prize winnings in 1901 +I'll see you on Wednesday \ No newline at end of file diff --git a/WbQYpeXWKHI.txt b/WbQYpeXWKHI.txt new file mode 100644 index 0000000000000000000000000000000000000000..8347df4e5af5db454f4e3f179d0bb747bb309746 --- /dev/null +++ b/WbQYpeXWKHI.txt @@ -0,0 +1,18771 @@ +align:start position:0% + +the following content is provided by MIT + + align:start position:0% +the following content is provided by MIT + + + align:start position:0% +the following content is provided by MIT +open courseware under a Creative Commons + + align:start position:0% +open courseware under a Creative Commons + + + align:start position:0% +open courseware under a Creative Commons +license additional information about our + + align:start position:0% +license additional information about our + + + align:start position:0% +license additional information about our +license and MIT open course Weare in + + align:start position:0% +license and MIT open course Weare in + + + align:start position:0% +license and MIT open course Weare in +general is available at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu okay good morning today the + + align:start position:0% +ocw.mit.edu okay good morning today the + + + align:start position:0% +ocw.mit.edu okay good morning today the +last day of our + + align:start position:0% +last day of our + + + align:start position:0% +last day of our +[Laughter] + + align:start position:0% +[Laughter] + + + align:start position:0% +[Laughter] +CSE we we do basically two two + + align:start position:0% +CSE we we do basically two two + + + align:start position:0% +CSE we we do basically two two +activities we will make again the + + align:start position:0% +activities we will make again the + + + align:start position:0% +activities we will make again the +exercise of critical moments reflection + + align:start position:0% +exercise of critical moments reflection + + + align:start position:0% +exercise of critical moments reflection +methodology that we made in the second + + align:start position:0% +methodology that we made in the second + + + align:start position:0% +methodology that we made in the second +day of the + + align:start position:0% +day of the + + + align:start position:0% +day of the +course and we will talk about the future + + align:start position:0% +course and we will talk about the future + + + align:start position:0% +course and we will talk about the future +of reflective practice in this new world + + align:start position:0% +of reflective practice in this new world + + + align:start position:0% +of reflective practice in this new world +that is + + align:start position:0% +that is + + + align:start position:0% +that is +emerging + + align:start position:0% + + + + align:start position:0% + +okay I will try to make you to remember + + align:start position:0% +okay I will try to make you to remember + + + align:start position:0% +okay I will try to make you to remember +to help you to remember the methodology + + align:start position:0% +to help you to remember the methodology + + + align:start position:0% +to help you to remember the methodology +the first step of the methodology is + + align:start position:0% +the first step of the methodology is + + + align:start position:0% +the first step of the methodology is +to formulate a question a question that + + align:start position:0% +to formulate a question a question that + + + align:start position:0% +to formulate a question a question that +will guide my mind in the analysis that + + align:start position:0% +will guide my mind in the analysis that + + + align:start position:0% +will guide my mind in the analysis that +I will be trying to to + + align:start position:0% +I will be trying to to + + + align:start position:0% +I will be trying to to +do and once we have the question we name + + align:start position:0% +do and once we have the question we name + + + align:start position:0% +do and once we have the question we name +it inquiring + + align:start position:0% +it inquiring + + + align:start position:0% +it inquiring +question we we step back to the + + align:start position:0% +question we we step back to the + + + align:start position:0% +question we we step back to the +experience trying to identify + + align:start position:0% + + + + align:start position:0% + +critical + + align:start position:0% +critical + + + align:start position:0% +critical +moments I will explain better what + + align:start position:0% +moments I will explain better what + + + align:start position:0% +moments I will explain better what +critical moments + + align:start position:0% +critical moments + + + align:start position:0% +critical moments +means and we will con reconstruct the + + align:start position:0% +means and we will con reconstruct the + + + align:start position:0% +means and we will con reconstruct the +experience through the critical moments + + align:start position:0% +experience through the critical moments + + + align:start position:0% +experience through the critical moments +and we will make an analysis of that + + align:start position:0% +and we will make an analysis of that + + + align:start position:0% +and we will make an analysis of that +okay + + align:start position:0% + + + + align:start position:0% + +so the first step is the inquiry + + align:start position:0% +so the first step is the inquiry + + + align:start position:0% +so the first step is the inquiry +question + + align:start position:0% + + + + align:start position:0% + +what you need to think about + + align:start position:0% +what you need to think about + + + align:start position:0% +what you need to think about +for defining your inquiry question is + + align:start position:0% +for defining your inquiry question is + + + align:start position:0% +for defining your inquiry question is +what + + align:start position:0% +what + + + align:start position:0% +what +questions if you had an answer + + align:start position:0% +questions if you had an answer + + + align:start position:0% +questions if you had an answer +to would help + + align:start position:0% +to would help + + + align:start position:0% +to would help +you to better apply reflective + + align:start position:0% +you to better apply reflective + + + align:start position:0% +you to better apply reflective +practice in your future + + align:start position:0% + + + + align:start position:0% + +activities okay + + align:start position:0% + + + + align:start position:0% + +the issue + + align:start position:0% + + + + align:start position:0% + +is reflective practice in my future + + align:start position:0% +is reflective practice in my future + + + align:start position:0% +is reflective practice in my future +activities how I can improve + + align:start position:0% +activities how I can improve + + + align:start position:0% +activities how I can improve +it and the question + + align:start position:0% +it and the question + + + align:start position:0% +it and the question +is what I need to answer for improving + + align:start position:0% +is what I need to answer for improving + + + align:start position:0% +is what I need to answer for improving +the application of reflective practice + + align:start position:0% +the application of reflective practice + + + align:start position:0% +the application of reflective practice +in my future activi + + align:start position:0% + + + + align:start position:0% + +this + + align:start position:0% + + + + align:start position:0% + +okay each one we formulate one question + + align:start position:0% +okay each one we formulate one question + + + align:start position:0% +okay each one we formulate one question +and we will collect as we did the second + + align:start position:0% +and we will collect as we did the second + + + align:start position:0% +and we will collect as we did the second +day of the course please write down what + + align:start position:0% +day of the course please write down what + + + align:start position:0% +day of the course please write down what +question you would like to + + align:start position:0% +question you would like to + + + align:start position:0% +question you would like to +to answer with the + + align:start position:0% +to answer with the + + + align:start position:0% +to answer with the +exercise about anything no about about + + align:start position:0% +exercise about anything no about about + + + align:start position:0% +exercise about anything no about about +anything that will help you to + + align:start position:0% +anything that will help you to + + + align:start position:0% +anything that will help you to +improve or to better apply reflective + + align:start position:0% +improve or to better apply reflective + + + align:start position:0% +improve or to better apply reflective +practice in your future + + align:start position:0% +practice in your future + + + align:start position:0% +practice in your future +activity + + align:start position:0% +activity + + + align:start position:0% +activity +okay thinking about your experience + + align:start position:0% +okay thinking about your experience + + + align:start position:0% +okay thinking about your experience +throughout the course what you would + + align:start position:0% +throughout the course what you would + + + align:start position:0% +throughout the course what you would +like to understand better for applying + + align:start position:0% +like to understand better for applying + + + align:start position:0% +like to understand better for applying +refle Ive + + align:start position:0% + + + + align:start position:0% + +practice okay go into your mind think on + + align:start position:0% +practice okay go into your mind think on + + + align:start position:0% +practice okay go into your mind think on +the challenges of applying reflective + + align:start position:0% +the challenges of applying reflective + + + align:start position:0% +the challenges of applying reflective +practice what you already know and what + + align:start position:0% +practice what you already know and what + + + align:start position:0% +practice what you already know and what +you are not so clear about and what + + align:start position:0% +you are not so clear about and what + + + align:start position:0% +you are not so clear about and what +question you would like to answer to + + align:start position:0% +question you would like to answer to + + + align:start position:0% +question you would like to answer to +have an answer okay + + align:start position:0% + + + + align:start position:0% + +she will come + + align:start position:0% +she will come + + + align:start position:0% +she will come +back see fore + + align:start position:0% + + + + align:start position:0% + +second + + align:start position:0% + + + + align:start position:0% + +we're thinking about the inquiry + + align:start position:0% +we're thinking about the inquiry + + + align:start position:0% +we're thinking about the inquiry +question yes okay + + align:start position:0% +question yes okay + + + align:start position:0% +question yes okay +yeah okay morning we have already begun + + align:start position:0% +yeah okay morning we have already begun + + + align:start position:0% +yeah okay morning we have already begun +we are trying to formulate an inquiry + + align:start position:0% +we are trying to formulate an inquiry + + + align:start position:0% +we are trying to formulate an inquiry +question for a reflection + + align:start position:0% +question for a reflection + + + align:start position:0% +question for a reflection +exercise + + align:start position:0% +exercise + + + align:start position:0% +exercise +okay where you will put in front of you + + align:start position:0% +okay where you will put in front of you + + + align:start position:0% +okay where you will put in front of you +for + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +speech + + align:start position:0% +speech + + + align:start position:0% +speech +foreign foreign speech + + align:start position:0% + + + + align:start position:0% + +now now let's begin + + align:start position:0% +now now let's begin + + + align:start position:0% +now now let's begin +[Music] + + align:start position:0% + + + + align:start position:0% + +okay okay let's begin + + align:start position:0% + + + + align:start position:0% + +your + + align:start position:0% +your + + + align:start position:0% +your +question um we had two do I just use one + + align:start position:0% +question um we had two do I just use one + + + align:start position:0% +question um we had two do I just use one +or okay one at a time my first thought + + align:start position:0% +or okay one at a time my first thought + + + align:start position:0% +or okay one at a time my first thought +was how to and this is what I thought I + + align:start position:0% +was how to and this is what I thought I + + + align:start position:0% +was how to and this is what I thought I +don't know what it means how to make + + align:start position:0% +don't know what it means how to make + + + align:start position:0% +don't know what it means how to make +reflective practice more practical okay + + align:start position:0% +reflective practice more practical okay + + + align:start position:0% +reflective practice more practical okay +how to make reflective practice more + + align:start position:0% +how to make reflective practice more + + + align:start position:0% +how to make reflective practice more +practical + + align:start position:0% + + + + align:start position:0% + +okay um how can I engage a community in + + align:start position:0% + + + + align:start position:0% + +learning from + + align:start position:0% +learning from + + + align:start position:0% +learning from +their + + align:start position:0% +their + + + align:start position:0% +their +organiz how + + align:start position:0% +organiz how + + + align:start position:0% +organiz how +can engage + + align:start position:0% +can engage + + + align:start position:0% +can engage +Community how can I best + + align:start position:0% + + + + align:start position:0% + +engage and learning and learning from + + align:start position:0% +engage and learning and learning from + + + align:start position:0% +engage and learning and learning from +their organiz + + align:start position:0% + + + + align:start position:0% + +Rel how can I use reflective practice + + align:start position:0% +Rel how can I use reflective practice + + + align:start position:0% +Rel how can I use reflective practice +skills + + align:start position:0% +skills + + + align:start position:0% +skills +in CL + + align:start position:0% + + + + align:start position:0% + +Rel to develop a close + + align:start position:0% +Rel to develop a close + + + align:start position:0% +Rel to develop a close +relation with the + + align:start position:0% +relation with the + + + align:start position:0% +relation with the +groups with the groups I am involved + + align:start position:0% +groups with the groups I am involved + + + align:start position:0% +groups with the groups I am involved +okay how can you apply with effective + + align:start position:0% +okay how can you apply with effective + + + align:start position:0% +okay how can you apply with effective +practice to Community + + align:start position:0% + + + + align:start position:0% + +Development how can we apply effective + + align:start position:0% +Development how can we apply effective + + + align:start position:0% +Development how can we apply effective +practice to Community Development to + + align:start position:0% +practice to Community Development to + + + align:start position:0% +practice to Community Development to +Community + + align:start position:0% + + + + align:start position:0% + +Development effective + + align:start position:0% + + + + align:start position:0% + +practice + + align:start position:0% +practice + + + align:start position:0% +practice +development um I'm not sure if I did + + align:start position:0% +development um I'm not sure if I did + + + align:start position:0% +development um I'm not sure if I did +this correctly okay I wrote down I + + align:start position:0% +this correctly okay I wrote down I + + + align:start position:0% +this correctly okay I wrote down I +understand the importance in respect of + + align:start position:0% +understand the importance in respect of + + + align:start position:0% +understand the importance in respect of +of individuals with disabilities in our + + align:start position:0% +of individuals with disabilities in our + + + align:start position:0% +of individuals with disabilities in our +workplaces members of the board of + + align:start position:0% +workplaces members of the board of + + + align:start position:0% +workplaces members of the board of +directors and participants in community + + align:start position:0% +directors and participants in community + + + align:start position:0% +directors and participants in community +organizations should I say it again yes + + align:start position:0% +organizations should I say it again yes + + + align:start position:0% +organizations should I say it again yes +okay question because this is an + + align:start position:0% +okay question because this is an + + + align:start position:0% +okay question because this is an +statement you need to formulate a + + align:start position:0% +statement you need to formulate a + + + align:start position:0% +statement you need to formulate a +question okay and then I wrote how do + + align:start position:0% +question okay and then I wrote how do + + + align:start position:0% +question okay and then I wrote how do +you educate people about the + + align:start position:0% +you educate people about the + + + align:start position:0% +you educate people about the +contributions of individuals with + + align:start position:0% +contributions of individuals with + + + align:start position:0% +contributions of individuals with +disabilities ensure their participation + + align:start position:0% +disabilities ensure their participation + + + align:start position:0% +disabilities ensure their participation +not so fast for en I wrote how do you + + align:start position:0% +not so fast for en I wrote how do you + + + align:start position:0% +not so fast for en I wrote how do you +educate people about the + + align:start position:0% + + + + align:start position:0% + +contributions can you synthesize a bit + + align:start position:0% +contributions can you synthesize a bit + + + align:start position:0% +contributions can you synthesize a bit +because we not be easy to okay can I + + align:start position:0% +because we not be easy to okay can I + + + align:start position:0% +because we not be easy to okay can I +think about it for a couple minutes + + align:start position:0% +think about it for a couple minutes + + + align:start position:0% +think about it for a couple minutes +while you're going around okay yes I + + align:start position:0% +while you're going around okay yes I + + + align:start position:0% +while you're going around okay yes I +wrote it too long maybe okay how to + + align:start position:0% +wrote it too long maybe okay how to + + + align:start position:0% +wrote it too long maybe okay how to +implement uh uh + + align:start position:0% +implement uh uh + + + align:start position:0% +implement uh uh +democracy uh on the reflection on the + + align:start position:0% +democracy uh on the reflection on the + + + align:start position:0% +democracy uh on the reflection on the +reflection PL yeah well + + align:start position:0% + + + + align:start position:0% + +democracy in into the reflection + + align:start position:0% +democracy in into the reflection + + + align:start position:0% +democracy in into the reflection +practice into the reflection of + + align:start position:0% +practice into the reflection of + + + align:start position:0% +practice into the reflection of +practice exercise more + + align:start position:0% +practice exercise more + + + align:start position:0% +practice exercise more +like what the difference how + + align:start position:0% +like what the difference how + + + align:start position:0% +like what the difference how +that how like democracy and + + align:start position:0% +that how like democracy and + + + align:start position:0% +that how like democracy and +reflection sometimes it's very confused + + align:start position:0% +reflection sometimes it's very confused + + + align:start position:0% +reflection sometimes it's very confused +with democracy is it can we can change + + align:start position:0% +with democracy is it can we can change + + + align:start position:0% +with democracy is it can we can change +the order should be how I can apply + + align:start position:0% +the order should be how I can apply + + + align:start position:0% +the order should be how I can apply +reflective practice in democracy okay on + + align:start position:0% +reflective practice in democracy okay on + + + align:start position:0% +reflective practice in democracy okay on +Democracy issues in democracy on the + + align:start position:0% +Democracy issues in democracy on the + + + align:start position:0% +Democracy issues in democracy on the +issues of + + align:start position:0% +issues of + + + align:start position:0% +issues of +democracy how we can Implement + + align:start position:0% +democracy how we can Implement + + + align:start position:0% +democracy how we can Implement +reflective + + align:start position:0% +reflective + + + align:start position:0% +reflective +practice to the issues of democracy okay + + align:start position:0% +practice to the issues of democracy okay + + + align:start position:0% +practice to the issues of democracy okay +thank + + align:start position:0% +thank + + + align:start position:0% +thank +you um I had three so I don't know I'll + + align:start position:0% +you um I had three so I don't know I'll + + + align:start position:0% +you um I had three so I don't know I'll +read what um what are the areas in which + + align:start position:0% +read what um what are the areas in which + + + align:start position:0% +read what um what are the areas in which +the group oh wait for + + align:start position:0% + + + + align:start position:0% + +uh what are the areas in which the group + + align:start position:0% +uh what are the areas in which the group + + + align:start position:0% +uh what are the areas in which the group +had the hardest time doing successfully + + align:start position:0% +had the hardest time doing successfully + + + align:start position:0% +had the hardest time doing successfully +and why how can we merge individual + + align:start position:0% +and why how can we merge individual + + + align:start position:0% +and why how can we merge individual +frames better and how can we more + + align:start position:0% +frames better and how can we more + + + align:start position:0% +frames better and how can we more +effectively become aware of our tcid + + align:start position:0% +effectively become aware of our tcid + + + align:start position:0% +effectively become aware of our tcid +assumptions so I don't know we could + + align:start position:0% +assumptions so I don't know we could + + + align:start position:0% +assumptions so I don't know we could +pick one out of + + align:start position:0% + + + + align:start position:0% + +those so what are the areas in which the + + align:start position:0% +those so what are the areas in which the + + + align:start position:0% +those so what are the areas in which the +group had + + align:start position:0% +group had + + + align:start position:0% +group had +difficulty uh + + align:start position:0% +difficulty uh + + + align:start position:0% +difficulty uh +a difficulty doing + + align:start position:0% + + + + align:start position:0% + +successfully and why or is that two + + align:start position:0% + + + + align:start position:0% + +questions + + align:start position:0% +questions + + + align:start position:0% +questions +okay um I was trying to figure out how + + align:start position:0% +okay um I was trying to figure out how + + + align:start position:0% +okay um I was trying to figure out how +to take this knowledge about reflective + + align:start position:0% +to take this knowledge about reflective + + + align:start position:0% +to take this knowledge about reflective +practice and implement it at an + + align:start position:0% +practice and implement it at an + + + align:start position:0% +practice and implement it at an +organizational how do I take the + + align:start position:0% +organizational how do I take the + + + align:start position:0% +organizational how do I take the +knowledge that I have and + + align:start position:0% +knowledge that I have and + + + align:start position:0% +knowledge that I have and +okay how to apply the knowledge about + + align:start position:0% +okay how to apply the knowledge about + + + align:start position:0% +okay how to apply the knowledge about +reflective practice in at a larger scale + + align:start position:0% +reflective practice in at a larger scale + + + align:start position:0% +reflective practice in at a larger scale +with either Community or organization or + + align:start position:0% +with either Community or organization or + + + align:start position:0% +with either Community or organization or +if I'm working in a group with a number + + align:start position:0% +if I'm working in a group with a number + + + align:start position:0% +if I'm working in a group with a number +of different people how do + + align:start position:0% +of different people how do + + + align:start position:0% +of different people how do +I if that's not already part of the + + align:start position:0% +I if that's not already part of the + + + align:start position:0% +I if that's not already part of the +process how do I bring that into the + + align:start position:0% +process how do I bring that into the + + + align:start position:0% +process how do I bring that into the +process + + align:start position:0% + + + + align:start position:0% + +MH that's this practice that allows your + + align:start position:0% +MH that's this practice that allows your + + + align:start position:0% +MH that's this practice that allows your +Escape okay you + + align:start position:0% +Escape okay you + + + align:start position:0% +Escape okay you +um is about how do we what steps + + align:start position:0% +um is about how do we what steps + + + align:start position:0% +um is about how do we what steps +necessary to make + + align:start position:0% + + + + align:start position:0% + +reflec how is it necessary for steps are + + align:start position:0% +reflec how is it necessary for steps are + + + align:start position:0% +reflec how is it necessary for steps are +necessary to make practice a habit a + + align:start position:0% +necessary to make practice a habit a + + + align:start position:0% +necessary to make practice a habit a +habit okay that it comes naturally + + align:start position:0% +habit okay that it comes naturally + + + align:start position:0% +habit okay that it comes naturally +okay + + align:start position:0% +okay + + + align:start position:0% +okay +okay to make effective practice + + align:start position:0% +okay to make effective practice + + + align:start position:0% +okay to make effective practice +habit + + align:start position:0% +habit + + + align:start position:0% +habit +okay + + align:start position:0% + + + + align:start position:0% + +natural um I think me I see like three + + align:start position:0% +natural um I think me I see like three + + + align:start position:0% +natural um I think me I see like three +of them up there that I would reiterate + + align:start position:0% +of them up there that I would reiterate + + + align:start position:0% +of them up there that I would reiterate +like Ezra's comment about how you you + + align:start position:0% +like Ezra's comment about how you you + + + align:start position:0% +like Ezra's comment about how you you +know integrate this into you know + + align:start position:0% +know integrate this into you know + + + align:start position:0% +know integrate this into you know +organizations that you work with in so I + + align:start position:0% +organizations that you work with in so I + + + align:start position:0% +organizations that you work with in so I +think that would be the biggest one for + + align:start position:0% +think that would be the biggest one for + + + align:start position:0% +think that would be the biggest one for +me okay this one + + align:start position:0% +me okay this one + + + align:start position:0% +me okay this one +okay now we need to select one of them + + align:start position:0% +okay now we need to select one of them + + + align:start position:0% +okay now we need to select one of them +oh as a grou as a group + + align:start position:0% + + + + align:start position:0% + +yes I yes Ed have you yeah I I made it a + + align:start position:0% +yes I yes Ed have you yeah I I made it a + + + align:start position:0% +yes I yes Ed have you yeah I I made it a +little shorter okay um this what I wrote + + align:start position:0% +little shorter okay um this what I wrote + + + align:start position:0% +little shorter okay um this what I wrote +I wrote how do I continue to include + + align:start position:0% +I wrote how do I continue to include + + + align:start position:0% +I wrote how do I continue to include +people with disabilities within + + align:start position:0% +people with disabilities within + + + align:start position:0% +people with disabilities within +Community organizations As + + align:start position:0% +Community organizations As + + + align:start position:0% +Community organizations As +Leaders yeah you want me say slowly how + + align:start position:0% +Leaders yeah you want me say slowly how + + + align:start position:0% +Leaders yeah you want me say slowly how +is that related to this yes the problem + + align:start position:0% +is that related to this yes the problem + + + align:start position:0% +is that related to this yes the problem +you you need a question that if you had + + align:start position:0% +you you need a question that if you had + + + align:start position:0% +you you need a question that if you had +an answer + + align:start position:0% +an answer + + + align:start position:0% +an answer +to it would help you apply reflective + + align:start position:0% +to it would help you apply reflective + + + align:start position:0% +to it would help you apply reflective +practice in your work in your future + + align:start position:0% +practice in your work in your future + + + align:start position:0% +practice in your work in your future +activities + + align:start position:0% + + + + align:start position:0% + +well I let me just say this maybe just + + align:start position:0% +well I let me just say this maybe just + + + align:start position:0% +well I let me just say this maybe just +say like I I've done a lot of work with + + align:start position:0% +say like I I've done a lot of work with + + + align:start position:0% +say like I I've done a lot of work with +including people with disabilities in my + + align:start position:0% +including people with disabilities in my + + + align:start position:0% +including people with disabilities in my +practice so I want to include more + + align:start position:0% +practice so I want to include more + + + align:start position:0% +practice so I want to include more +people with disabilities in + + align:start position:0% +people with disabilities in + + + align:start position:0% +people with disabilities in +organizations As Leaders because a lot + + align:start position:0% +organizations As Leaders because a lot + + + align:start position:0% +organizations As Leaders because a lot +of times they don't have equal + + align:start position:0% +of times they don't have equal + + + align:start position:0% +of times they don't have equal +opportunity you would like to apply + + align:start position:0% +opportunity you would like to apply + + + align:start position:0% +opportunity you would like to apply +reflective practice to this kind of + + align:start position:0% +reflective practice to this kind of + + + align:start position:0% +reflective practice to this kind of +issue yes okay or how to apply refective + + align:start position:0% +issue yes okay or how to apply refective + + + align:start position:0% +issue yes okay or how to apply refective +practice for including individuals with + + align:start position:0% +practice for including individuals with + + + align:start position:0% +practice for including individuals with +disabilities individuals with disability + + align:start position:0% +disabilities individuals with disability + + + align:start position:0% +disabilities individuals with disability +okay I'm think it's + + align:start position:0% + + + + align:start position:0% + +okay so do you do you see any here that + + align:start position:0% +okay so do you do you see any here that + + + align:start position:0% +okay so do you do you see any here that +can be combined that are similar that + + align:start position:0% +can be combined that are similar that + + + align:start position:0% +can be combined that are similar that +are the same let's look first for for + + align:start position:0% +are the same let's look first for for + + + align:start position:0% +are the same let's look first for for +any any questions that may + + align:start position:0% +any any questions that may + + + align:start position:0% +any any questions that may +be + + align:start position:0% + + + + align:start position:0% + +duplicates yes I think um the maybe make + + align:start position:0% +duplicates yes I think um the maybe make + + + align:start position:0% +duplicates yes I think um the maybe make +reflective practice more practical and + + align:start position:0% +reflective practice more practical and + + + align:start position:0% +reflective practice more practical and +making it a habit or + + align:start position:0% +making it a habit or + + + align:start position:0% +making it a habit or +similar okay okay + + align:start position:0% + + + + align:start position:0% + +I think they're actually a little + + align:start position:0% +I think they're actually a little + + + align:start position:0% +I think they're actually a little +different I they're related but I don't + + align:start position:0% +different I they're related but I don't + + + align:start position:0% +different I they're related but I don't +think they're the exact same question I + + align:start position:0% +think they're the exact same question I + + + align:start position:0% +think they're the exact same question I +mean practical means it's making it kind + + align:start position:0% +mean practical means it's making it kind + + + align:start position:0% +mean practical means it's making it kind +of convenient and simple or is making it + + align:start position:0% +of convenient and simple or is making it + + + align:start position:0% +of convenient and simple or is making it +a habit of sort of doing it + + align:start position:0% + + + + align:start position:0% + +consistently similar okay let's go do we + + align:start position:0% +consistently similar okay let's go do we + + + align:start position:0% +consistently similar okay let's go do we +find any any + + align:start position:0% + + + + align:start position:0% + +I go + + align:start position:0% +I go + + + align:start position:0% +I go +another + + align:start position:0% + + + + align:start position:0% + +question what were you saying + + align:start position:0% +question what were you saying + + + align:start position:0% +question what were you saying +cine I'm + + align:start position:0% +cine I'm + + + align:start position:0% +cine I'm +thinking see with i i + + align:start position:0% + + + + align:start position:0% + +MH f and g are like the same + + align:start position:0% + + + + align:start position:0% + +statement + + align:start position:0% + + + + align:start position:0% + +yeah if is the same G is a phrase of f + + align:start position:0% +yeah if is the same G is a phrase of f + + + align:start position:0% +yeah if is the same G is a phrase of f +you can eliminate + + align:start position:0% +you can eliminate + + + align:start position:0% +you can eliminate +F I think c and d c would kind of fall + + align:start position:0% +F I think c and d c would kind of fall + + + align:start position:0% +F I think c and d c would kind of fall +not no I'm sorry not c um B I think B + + align:start position:0% +not no I'm sorry not c um B I think B + + + align:start position:0% +not no I'm sorry not c um B I think B +and D are + + align:start position:0% + + + + align:start position:0% + +related how can I apply reflective + + align:start position:0% +related how can I apply reflective + + + align:start position:0% +related how can I apply reflective +practice to Community Development and + + align:start position:0% +practice to Community Development and + + + align:start position:0% +practice to Community Development and +how + + align:start position:0% +how + + + align:start position:0% +how +can can I engage a community in learning + + align:start position:0% +can can I engage a community in learning + + + align:start position:0% +can can I engage a community in learning +from their organizing work b b and + + align:start position:0% +from their organizing work b b and + + + align:start position:0% +from their organizing work b b and +yes and is more General than right + + align:start position:0% +yes and is more General than right + + + align:start position:0% +yes and is more General than right +exactly both of those could be a subset + + align:start position:0% +exactly both of those could be a subset + + + align:start position:0% +exactly both of those could be a subset +of I because they're types of + + align:start position:0% +of I because they're types of + + + align:start position:0% +of I because they're types of +organizations okay yeah appage do you + + align:start position:0% +organizations okay yeah appage do you + + + align:start position:0% +organizations okay yeah appage do you +see another kind + + align:start position:0% + + + + align:start position:0% + +of sort of like a topic + + align:start position:0% + + + + align:start position:0% + +area that's even more + + align:start position:0% + + + + align:start position:0% + +okay wish + + align:start position:0% +okay wish + + + align:start position:0% +okay wish +could a right now that we're kind of + + align:start position:0% +could a right now that we're kind of + + + align:start position:0% +could a right now that we're kind of +able to combine with + + align:start position:0% +able to combine with + + + align:start position:0% +able to combine with +J B and + + align:start position:0% +J B and + + + align:start position:0% +J B and +D with I anything with regards to H and + + align:start position:0% +D with I anything with regards to H and + + + align:start position:0% +D with I anything with regards to H and +G + + align:start position:0% +G + + + align:start position:0% +G +and + + align:start position:0% + + + + align:start position:0% + +see I think how can we apply the + + align:start position:0% +see I think how can we apply the + + + align:start position:0% +see I think how can we apply the +knowledge about practice at a larger + + align:start position:0% +knowledge about practice at a larger + + + align:start position:0% +knowledge about practice at a larger +scale and how can we Implement + + align:start position:0% +scale and how can we Implement + + + align:start position:0% +scale and how can we Implement +reflective practice to the issues of + + align:start position:0% +reflective practice to the issues of + + + align:start position:0% +reflective practice to the issues of +democracy + + align:start position:0% +democracy + + + align:start position:0% +democracy +Rel larg + + align:start position:0% +Rel larg + + + align:start position:0% +Rel larg +scale are related the question is that + + align:start position:0% +scale are related the question is that + + + align:start position:0% +scale are related the question is that +in G it's tost in specific issue and the + + align:start position:0% +in G it's tost in specific issue and the + + + align:start position:0% +in G it's tost in specific issue and the +other + + align:start position:0% +other + + + align:start position:0% +other +is to different kind of issues + + align:start position:0% +is to different kind of issues + + + align:start position:0% +is to different kind of issues +no that B and D were under + + align:start position:0% + + + + align:start position:0% + +I okay okay so if you were then to try + + align:start position:0% +I okay okay so if you were then to try + + + align:start position:0% +I okay okay so if you were then to try +if if you were then to try to combine A + + align:start position:0% +if if you were then to try to combine A + + + align:start position:0% +if if you were then to try to combine A +and J how would you combine it + + align:start position:0% + + + + align:start position:0% + +mean in One + + align:start position:0% + + + + align:start position:0% + +S how can we make reflective practice + + align:start position:0% +S how can we make reflective practice + + + align:start position:0% +S how can we make reflective practice +common + + align:start position:0% + + + + align:start position:0% + +practice mhm + + align:start position:0% + + + + align:start position:0% + +but then you don't include the Practical + + align:start position:0% +but then you don't include the Practical + + + align:start position:0% +but then you don't include the Practical +part + + align:start position:0% +part + + + align:start position:0% +part +right I guess it's somewhat impli what + + align:start position:0% +right I guess it's somewhat impli what + + + align:start position:0% +right I guess it's somewhat impli what +do you + + align:start position:0% +do you + + + align:start position:0% +do you +think more + + align:start position:0% +think more + + + align:start position:0% +think more +practical and natural how that okay is + + align:start position:0% +practical and natural how that okay is + + + align:start position:0% +practical and natural how that okay is +that good okay good all right yeah now + + align:start position:0% +that good okay good all right yeah now + + + align:start position:0% +that good okay good all right yeah now +this one here B andd how can we engage + + align:start position:0% +this one here B andd how can we engage + + + align:start position:0% +this one here B andd how can we engage +community in learning from their + + align:start position:0% +community in learning from their + + + align:start position:0% +community in learning from their +organizing work and how can we apply + + align:start position:0% +organizing work and how can we apply + + + align:start position:0% +organizing work and how can we apply +reflective practice to Community + + align:start position:0% + + + + align:start position:0% + +Development how do you prefer to and + + align:start position:0% +Development how do you prefer to and + + + align:start position:0% +Development how do you prefer to and +then you've got the element here of how + + align:start position:0% +then you've got the element here of how + + + align:start position:0% +then you've got the element here of how +to how to take reflective practice to a + + align:start position:0% +to how to take reflective practice to a + + + align:start position:0% +to how to take reflective practice to a +larger scale + + align:start position:0% + + + + align:start position:0% + +how can we apply we could to take the d + + align:start position:0% +how can we apply we could to take the d + + + align:start position:0% +how can we apply we could to take the d +as starting + + align:start position:0% + + + + align:start position:0% + +point or not I mean I don't know I have + + align:start position:0% +point or not I mean I don't know I have + + + align:start position:0% +point or not I mean I don't know I have +a question about where we're trying to + + align:start position:0% +a question about where we're trying to + + + align:start position:0% +a question about where we're trying to +get to maybe that's my question if if we + + align:start position:0% +get to maybe that's my question if if we + + + align:start position:0% +get to maybe that's my question if if we +could rephrase the questions in a way + + align:start position:0% +could rephrase the questions in a way + + + align:start position:0% +could rephrase the questions in a way +that integrate the interest of everybody + + align:start position:0% +that integrate the interest of everybody + + + align:start position:0% +that integrate the interest of everybody +no of the two persons who formate no no + + align:start position:0% +no of the two persons who formate no no + + + align:start position:0% +no of the two persons who formate no no +that's our that's our immediate step + + align:start position:0% +that's our that's our immediate step + + + align:start position:0% +that's our that's our immediate step +what's our second step after that we + + align:start position:0% +what's our second step after that we + + + align:start position:0% +what's our second step after that we +will s two or three of these two or + + align:start position:0% +will s two or three of these two or + + + align:start position:0% +will s two or three of these two or +three + + align:start position:0% + + + + align:start position:0% + +okay I think that there's a thing + + align:start position:0% +okay I think that there's a thing + + + align:start position:0% +okay I think that there's a thing +about I think that uh D could + + align:start position:0% +about I think that uh D could + + + align:start position:0% +about I think that uh D could +be + + align:start position:0% +be + + + align:start position:0% +be +the it could be the the general + + align:start position:0% +the it could be the the general + + + align:start position:0% +the it could be the the general +organizing could fall under D so it + + align:start position:0% +organizing could fall under D so it + + + align:start position:0% +organizing could fall under D so it +could be a natural Evolution from from + + align:start position:0% +could be a natural Evolution from from + + + align:start position:0% +could be a natural Evolution from from +Community Development rather so I guess + + align:start position:0% +Community Development rather so I guess + + + align:start position:0% +Community Development rather so I guess +I'm saying that + + align:start position:0% +I'm saying that + + + align:start position:0% +I'm saying that +um how can + + align:start position:0% +um how can + + + align:start position:0% +um how can +app + + align:start position:0% + + + + align:start position:0% + +engage how can we engage community in + + align:start position:0% +engage how can we engage community in + + + align:start position:0% +engage how can we engage community in +using refective practice for their + + align:start position:0% + + + + align:start position:0% + +development is it like a change from I + + align:start position:0% +development is it like a change from I + + + align:start position:0% +development is it like a change from I +to D to B like I is the least specific + + align:start position:0% +to D to B like I is the least specific + + + align:start position:0% +to D to B like I is the least specific +General D is Community Development is + + align:start position:0% +General D is Community Development is + + + align:start position:0% +General D is Community Development is +specific element development okay + + align:start position:0% +specific element development okay + + + align:start position:0% +specific element development okay +because I is so General I could see the + + align:start position:0% +because I is so General I could see the + + + align:start position:0% +because I is so General I could see the +AJ falling under ey my suggestion is + + align:start position:0% +AJ falling under ey my suggestion is + + + align:start position:0% +AJ falling under ey my suggestion is +please + + align:start position:0% +please + + + align:start position:0% +please +propose + + align:start position:0% +propose + + + align:start position:0% +propose +phrases + + align:start position:0% +phrases + + + align:start position:0% +phrases +okay did you say what you what you just + + align:start position:0% +okay did you say what you what you just + + + align:start position:0% +okay did you say what you what you just +said could you repeat what you just said + + align:start position:0% +said could you repeat what you just said + + + align:start position:0% +said could you repeat what you just said +in terms of combining them how can we + + align:start position:0% +in terms of combining them how can we + + + align:start position:0% +in terms of combining them how can we +engage communities in the in the use of + + align:start position:0% +engage communities in the in the use of + + + align:start position:0% +engage communities in the in the use of +reflective practice for their + + align:start position:0% +reflective practice for their + + + align:start position:0% +reflective practice for their +development + + align:start position:0% +development + + + align:start position:0% +development +yes + + align:start position:0% +yes + + + align:start position:0% +yes +okay + + align:start position:0% +okay + + + align:start position:0% +okay +okay so does that take in + + align:start position:0% +okay so does that take in + + + align:start position:0% +okay so does that take in +I does that cover + + align:start position:0% + + + + align:start position:0% + +I does that include I + + align:start position:0% +I does that include I + + + align:start position:0% +I does that include I +that no I I'm not trying + + align:start position:0% +that no I I'm not trying + + + align:start position:0% +that no I I'm not trying +to yes + + align:start position:0% +to yes + + + align:start position:0% +to yes +okay how can we engage communities to + + align:start position:0% +okay how can we engage communities to + + + align:start position:0% +okay how can we engage communities to +use effective practice for their + + align:start position:0% +use effective practice for their + + + align:start position:0% +use effective practice for their +development okay so can we put new new + + align:start position:0% +development okay so can we put new new + + + align:start position:0% +development okay so can we put new new +new letters for + + align:start position:0% + + + + align:start position:0% + +this + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +okay now please select + + align:start position:0% +okay now please select + + + align:start position:0% +okay now please select +two of these that you would like to to + + align:start position:0% +two of these that you would like to to + + + align:start position:0% +two of these that you would like to to +answer first silently no as + + align:start position:0% + + + + align:start position:0% + +always any two on the yes any + + align:start position:0% + + + + align:start position:0% + +two she's eliminating the question that + + align:start position:0% +two she's eliminating the question that + + + align:start position:0% +two she's eliminating the question that +are already + + align:start position:0% +are already + + + align:start position:0% +are already +reformulated what numbers did the top so + + align:start position:0% +reformulated what numbers did the top so + + + align:start position:0% +reformulated what numbers did the top so +I'm leaving I okay cuz we never yeah + + align:start position:0% +I'm leaving I okay cuz we never yeah + + + align:start position:0% +I'm leaving I okay cuz we never yeah +in + + align:start position:0% +in + + + align:start position:0% +in +okay + + align:start position:0% + + + + align:start position:0% + +okay can you repeat that c for me how to + + align:start position:0% +okay can you repeat that c for me how to + + + align:start position:0% +okay can you repeat that c for me how to +use effective + + align:start position:0% +use effective + + + align:start position:0% +use effective +practice skills to develop a closer + + align:start position:0% +practice skills to develop a closer + + + align:start position:0% +practice skills to develop a closer +relationship with the group I'm involved + + align:start position:0% +relationship with the group I'm involved + + + align:start position:0% +relationship with the group I'm involved +with + + align:start position:0% + + + + align:start position:0% + +okay let's + + align:start position:0% +okay let's + + + align:start position:0% +okay let's +me your + + align:start position:0% +me your + + + align:start position:0% +me your +letters which one I want to work on huh + + align:start position:0% +letters which one I want to work on huh + + + align:start position:0% +letters which one I want to work on huh +just one two two + + align:start position:0% +just one two two + + + align:start position:0% +just one two two +okay I or + + align:start position:0% + + + + align:start position:0% + +l i i + + align:start position:0% +l i i + + + align:start position:0% +l i i +okay + + align:start position:0% +okay + + + align:start position:0% +okay +you um l or l or + + align:start position:0% +you um l or l or + + + align:start position:0% +you um l or l or +l l l you can have another choice if you + + align:start position:0% + + + + align:start position:0% + +want I m I m I + + align:start position:0% + + + + align:start position:0% + +okay I wrote down mc + + align:start position:0% +okay I wrote down mc + + + align:start position:0% +okay I wrote down mc +mc + + align:start position:0% + + + + align:start position:0% + +CC okay I would say MC as well C and + + align:start position:0% +CC okay I would say MC as well C and + + + align:start position:0% +CC okay I would say MC as well C and +what m m okay H and I H and + + align:start position:0% + + + + align:start position:0% + +I gosh all + + align:start position:0% +I gosh all + + + align:start position:0% +I gosh all +right l i l and + + align:start position:0% +right l i l and + + + align:start position:0% +right l i l and +i l + + align:start position:0% + + + + align:start position:0% + +i m and I M and I I didn't realize M and + + align:start position:0% +i m and I M and I I didn't realize M and + + + align:start position:0% +i m and I M and I I didn't realize M and +I you um l and i l and i + + align:start position:0% + + + + align:start position:0% + +yes okay + + align:start position:0% +yes okay + + + align:start position:0% +yes okay +you okay so we + + align:start position:0% +you okay so we + + + align:start position:0% +you okay so we +have basically three questions + + align:start position:0% +have basically three questions + + + align:start position:0% +have basically three questions +no we can work with how we + + align:start position:0% +no we can work with how we + + + align:start position:0% +no we can work with how we +make common + + align:start position:0% +make common + + + align:start position:0% +make common +practice reflective practice a common + + align:start position:0% +practice reflective practice a common + + + align:start position:0% +practice reflective practice a common +practice to make it practical and + + align:start position:0% +practice to make it practical and + + + align:start position:0% +practice to make it practical and +natural natural no yes how we can engage + + align:start position:0% +natural natural no yes how we can engage + + + align:start position:0% +natural natural no yes how we can engage +communities to use reflective practice + + align:start position:0% +communities to use reflective practice + + + align:start position:0% +communities to use reflective practice +for their + + align:start position:0% +for their + + + align:start position:0% +for their +development and how do you + + align:start position:0% +development and how do you + + + align:start position:0% +development and how do you +do apply the knowledge about reflective + + align:start position:0% +do apply the knowledge about reflective + + + align:start position:0% +do apply the knowledge about reflective +practice at a larger scale + + align:start position:0% +practice at a larger scale + + + align:start position:0% +practice at a larger scale +okay we will write these questions in a + + align:start position:0% +okay we will write these questions in a + + + align:start position:0% +okay we will write these questions in a +sheet of + + align:start position:0% +sheet of + + + align:start position:0% +sheet of +paper + + align:start position:0% +paper + + + align:start position:0% +paper +and we we watch The Next + + align:start position:0% +and we we watch The Next + + + align:start position:0% +and we we watch The Next +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +Step the next step is + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +no try to remember the + + align:start position:0% +no try to remember the + + + align:start position:0% +no try to remember the +course okay + + align:start position:0% + + + + align:start position:0% + +and try + + align:start position:0% +and try + + + align:start position:0% +and try +to recover your critical + + align:start position:0% +to recover your critical + + + align:start position:0% +to recover your critical +moments are moments that you perceive as + + align:start position:0% +moments are moments that you perceive as + + + align:start position:0% +moments are moments that you perceive as +important because they have they + + align:start position:0% + + + + align:start position:0% + +was positive or negative + + align:start position:0% +was positive or negative + + + align:start position:0% +was positive or negative +because they was meaningful for you in a + + align:start position:0% +because they was meaningful for you in a + + + align:start position:0% +because they was meaningful for you in a +positive way or negative + + align:start position:0% + + + + align:start position:0% + +way not + + align:start position:0% + + + + align:start position:0% + +necessarily in the in the + + align:start position:0% +necessarily in the in the + + + align:start position:0% +necessarily in the in the +CSE but related to the C you may have a + + align:start position:0% +CSE but related to the C you may have a + + + align:start position:0% +CSE but related to the C you may have a +critical moment in your house thinking + + align:start position:0% +critical moment in your house thinking + + + align:start position:0% +critical moment in your house thinking +about the + + align:start position:0% +about the + + + align:start position:0% +about the +curse okay or trying to make a task for + + align:start position:0% +curse okay or trying to make a task for + + + align:start position:0% +curse okay or trying to make a task for +the + + align:start position:0% +the + + + align:start position:0% +the +course okay but should be critical + + align:start position:0% +course okay but should be critical + + + align:start position:0% +course okay but should be critical +moments of your learning + + align:start position:0% +moments of your learning + + + align:start position:0% +moments of your learning +process relative to the related to + + align:start position:0% +process relative to the related to + + + align:start position:0% +process relative to the related to +reflective reflective + + align:start position:0% +reflective reflective + + + align:start position:0% +reflective reflective +prce okay then we should come up with + + align:start position:0% +prce okay then we should come up with + + + align:start position:0% +prce okay then we should come up with +you need to write eight eight eight yes + + align:start position:0% +you need to write eight eight eight yes + + + align:start position:0% +you need to write eight eight eight yes +the you have a with eight + + align:start position:0% +the you have a with eight + + + align:start position:0% +the you have a with eight +and as you can see first of all you will + + align:start position:0% +and as you can see first of all you will + + + align:start position:0% +and as you can see first of all you will +write the name of the critical moment + + align:start position:0% +write the name of the critical moment + + + align:start position:0% +write the name of the critical moment +after that a brief phrase describing + + align:start position:0% + + + + align:start position:0% + +it and once you have all the critical + + align:start position:0% +it and once you have all the critical + + + align:start position:0% +it and once you have all the critical +moments already + + align:start position:0% +moments already + + + align:start position:0% +moments already +identified try to + + align:start position:0% +identified try to + + + align:start position:0% +identified try to +establish the level of importance for + + align:start position:0% +establish the level of importance for + + + align:start position:0% +establish the level of importance for +you let's work with two levels + + align:start position:0% +you let's work with two levels + + + align:start position:0% +you let's work with two levels +one and two and notice that on the Forum + + align:start position:0% +one and two and notice that on the Forum + + + align:start position:0% +one and two and notice that on the Forum +there's a for your + + align:start position:0% +there's a for your + + + align:start position:0% +there's a for your +name and what group you belong + + align:start position:0% +name and what group you belong + + + align:start position:0% +name and what group you belong +to we + + align:start position:0% +to we + + + align:start position:0% +to we +are just put a if you're an mCP student + + align:start position:0% +are just put a if you're an mCP student + + + align:start position:0% +are just put a if you're an mCP student +B if you're crcp affiliate and C if + + align:start position:0% +B if you're crcp affiliate and C if + + + align:start position:0% +B if you're crcp affiliate and C if +you're + + align:start position:0% +you're + + + align:start position:0% +you're +other + + align:start position:0% + + + + align:start position:0% + +okay and then are we + + align:start position:0% +okay and then are we + + + align:start position:0% +okay and then are we +same yeah the same thing the same thing + + align:start position:0% + + + + align:start position:0% + +okay the same + + align:start position:0% + + + + align:start position:0% + +thing there's two priority levels yes + + align:start position:0% +thing there's two priority levels yes + + + align:start position:0% +thing there's two priority levels yes +which is the highest you decide which + + align:start position:0% +which is the highest you decide which + + + align:start position:0% +which is the highest you decide which +one you think that are more meaningful + + align:start position:0% +one you think that are more meaningful + + + align:start position:0% +one you think that are more meaningful +for your process no is a one a higher or + + align:start position:0% +for your process no is a one a higher or + + + align:start position:0% +for your process no is a one a higher or +two a + + align:start position:0% +two a + + + align:start position:0% +two a +Higher One higher in terms of what + + align:start position:0% +Higher One higher in terms of what + + + align:start position:0% +Higher One higher in terms of what +importance for you personally + + align:start position:0% +importance for you personally + + + align:start position:0% +importance for you personally +what do you think + + align:start position:0% +what do you think + + + align:start position:0% +what do you think +that + + align:start position:0% +that + + + align:start position:0% +that +ER were more meaningful for you and one + + align:start position:0% +ER were more meaningful for you and one + + + align:start position:0% +ER were more meaningful for you and one +is high one is high + + align:start position:0% +is high one is high + + + align:start position:0% +is high one is high +okay Sebastian I have a question yes can + + align:start position:0% +okay Sebastian I have a question yes can + + + align:start position:0% +okay Sebastian I have a question yes can +it be connected to your your + + align:start position:0% +it be connected to your your + + + align:start position:0% +it be connected to your your +professional + + align:start position:0% +professional + + + align:start position:0% +professional +work talk what you learn from the class + + align:start position:0% +work talk what you learn from the class + + + align:start position:0% +work talk what you learn from the class +can it be applied to experiences in + + align:start position:0% +can it be applied to experiences in + + + align:start position:0% +can it be applied to experiences in +community organizing is that okay I'm + + align:start position:0% +community organizing is that okay I'm + + + align:start position:0% +community organizing is that okay I'm +not quite clear enough it myself + + align:start position:0% +not quite clear enough it myself + + + align:start position:0% +not quite clear enough it myself +the timeline is critical moments for + + align:start position:0% +the timeline is critical moments for + + + align:start position:0% +the timeline is critical moments for +your learning process related to + + align:start position:0% +your learning process related to + + + align:start position:0% +your learning process related to +reflective practice okay over the last + + align:start position:0% +reflective practice okay over the last + + + align:start position:0% +reflective practice okay over the last +two weeks last two weeks or as long as + + align:start position:0% +two weeks last two weeks or as long as + + + align:start position:0% +two weeks last two weeks or as long as +I've been here and the days you have + + align:start position:0% +I've been here and the days you have + + + align:start position:0% +I've been here and the days you have +been here I think okay okay + + align:start position:0% + + + + align:start position:0% + +okay and + + align:start position:0% + + + + align:start position:0% + +you + + align:start position:0% + + + + align:start position:0% + +write we have 10 days in the course okay + + align:start position:0% +write we have 10 days in the course okay + + + align:start position:0% +write we have 10 days in the course okay +day one day two 3 4 + + align:start position:0% + + + + align:start position:0% + +5 six for the + + align:start position:0% +5 six for the + + + align:start position:0% +5 six for the +weekend if you have some thing in the + + align:start position:0% +weekend if you have some thing in the + + + align:start position:0% +weekend if you have some thing in the +weekend okay okay + + align:start position:0% +weekend okay okay + + + align:start position:0% +weekend okay okay +7 8 9 10 and 11 + + align:start position:0% + + + + align:start position:0% + +10 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in the + + + align:start position:0% +you can go through your emotions in the +course okay critical moments are highly + + align:start position:0% +course okay critical moments are highly + + + align:start position:0% +course okay critical moments are highly +related with our how we were f + + align:start position:0% + + + + align:start position:0% + +speee + + align:start position:0% + + + + align:start position:0% + +foreign + + align:start position:0% +foreign + + + align:start position:0% +foreign +speee + + align:start position:0% +speee + + + align:start position:0% +speee +spee fo + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +I BR my + + align:start position:0% +I BR my + + + align:start position:0% +I BR my +daughter + + align:start position:0% + + + + align:start position:0% + +yes experience with + + align:start position:0% + + + + align:start position:0% + +English + + align:start 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it's clear just go + + + align:start position:0% +critical moment once it's clear just go +to the next one + + align:start position:0% + + + + align:start position:0% + +don't try to be to be + + align:start position:0% + + + + align:start position:0% + +precise you + + align:start position:0% + + + + align:start position:0% + +what it's a process of retrieving of our + + align:start position:0% +what it's a process of retrieving of our + + + align:start position:0% +what it's a process of retrieving of our +memory + + align:start position:0% + + + + align:start position:0% + +good + + align:start position:0% + + + + align:start position:0% + +need + + align:start position:0% + + + + align:start position:0% + +see be better + + align:start position:0% + + + + align:start position:0% + +we + + align:start position:0% +we + + + align:start position:0% +we +are privity level and then here here the + + align:start position:0% +are privity level and then here here the + + + align:start 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position:0% +critical Moments One critical moment in +each index card + + align:start position:0% +each index card + + + align:start position:0% +each index card +with big + + align:start position:0% +with big + + + align:start position:0% +with big +letters for helping us to read so here + + align:start position:0% +letters for helping us to read so here + + + align:start position:0% +letters for helping us to read so here +you have your new s mark + + align:start position:0% + + + + align:start position:0% + +no no + + align:start position:0% + + + + align:start position:0% + +here oh we were going to talk to you and + + align:start position:0% +here oh we were going to talk to you and + + + align:start position:0% +here oh we were going to talk to you and +ask you because you've been here + + align:start position:0% +ask you because you've been here + + + align:start position:0% +ask you because you've been here +days interesting for + + align:start position:0% +days interesting for 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and we have until 11 + + + align:start position:0% +seven so we 8 9 and we have until 11 +okay now six is + + align:start position:0% + + + + align:start position:0% + +weend remember EV has a + + align:start position:0% +weend remember EV has a + + + align:start position:0% +weend remember EV has a +date process may be + + align:start position:0% +date process may be + + + align:start position:0% +date process may be +longer but we are talking about + + align:start position:0% +longer but we are talking about + + + align:start position:0% +longer but we are talking about +events critical moments are + + align:start position:0% +events critical moments are + + + align:start position:0% +events critical moments are +moments not + + align:start position:0% +moments not + + + align:start position:0% +moments not +processes and now we from these eight we + + align:start position:0% +processes and now we from these eight we + + + align:start position:0% +processes and now we from these 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align:start position:0% +yet those of you who are ready no no no +we can wait everyone to finish + + align:start position:0% +we can wait everyone to finish + + + align:start position:0% +we can wait everyone to finish +okay + + align:start position:0% + + + + align:start position:0% + +what four four okay the form more + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +important have you finished we are just + + align:start position:0% +important have you finished we are just + + + align:start position:0% +important have you finished we are just +waiting for you put here I just + + align:start position:0% +waiting for you put here I just + + + align:start position:0% +waiting for you put here I just +yeah please at the + + align:start position:0% + + + + align:start position:0% + +back more beautiful with + + align:start position:0% + + + + align:start position:0% + +thisan just the title the title just the + + align:start position:0% +thisan just the title the title just the + + + align:start position:0% +thisan just the title the title just the +title of the event of what happened this + + align:start position:0% +title of the event of what happened this + + + align:start position:0% +title of the event of what happened this +day okay + + align:start position:0% +day okay + + + align:start position:0% +day okay +okay + + align:start position:0% +okay + + + align:start position:0% +okay +okay we I we know that some of you have + + align:start position:0% +okay we I we know that some of you have + + + align:start position:0% +okay we I we know that some of you have +already finished but we need to wait + + align:start position:0% +already finished but we need to wait + + + align:start position:0% +already finished but we need to wait +everyone to finish before to + + align:start position:0% +everyone to finish before to + + + align:start position:0% +everyone to finish before to +begin the next + + align:start position:0% + + + + align:start position:0% + +step and remember to to put the date of + + align:start position:0% +step and remember to to put the date of + + + align:start position:0% +step and remember to to put the date of +the event in this + + align:start position:0% +the event in this + + + align:start position:0% +the event in this +way in + + align:start position:0% + + + + align:start position:0% + +this if it was before the course you put + + align:start position:0% +this if it was before the course you put + + + align:start position:0% +this if it was before the course you put +zero if it was in the first week of the + + align:start position:0% +zero if it was in the first week of the + + + align:start position:0% +zero if it was in the first week of the +course 1 2 3 4 or five if it was in the + + align:start position:0% +course 1 2 3 4 or five if it was in the + + + align:start position:0% +course 1 2 3 4 or five if it was in the +weekend six and the other days of the + + align:start position:0% +weekend six and the other days of the + + + align:start position:0% +weekend six and the other days of the +course are 7 8 9 10 and 11 okay one + + align:start position:0% +course are 7 8 9 10 and 11 okay one + + + align:start position:0% +course are 7 8 9 10 and 11 okay one +number more than the day of the + + align:start position:0% +number more than the day of the + + + align:start position:0% +number more than the day of the +course okay + + align:start position:0% + + + + align:start position:0% + +okay and to maintain the number listen + + align:start position:0% +okay and to maintain the number listen + + + align:start position:0% +okay and to maintain the number listen +[Laughter] + + align:start position:0% +[Laughter] + + + align:start position:0% +[Laughter] +Le + + align:start position:0% +Le + + + align:start position:0% +Le +okay yeah + + align:start position:0% + + + + align:start position:0% + +you + + align:start position:0% + + + + align:start position:0% + +what Happ + + align:start position:0% +what Happ + + + align:start position:0% +what Happ +[Music] + + align:start position:0% + + + + align:start position:0% + +right okay + + align:start position:0% + + + + align:start position:0% + +okay you + + align:start position:0% + + + + align:start position:0% + +it's fore + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +yeah okay let's begin who wants to + + align:start position:0% +yeah okay let's begin who wants to + + + align:start position:0% +yeah okay let's begin who wants to +start the person who each person will + + align:start position:0% +start the person who each person will + + + align:start position:0% +start the person who each person will +come here and + + align:start position:0% +come here and + + + align:start position:0% +come here and +we put the kit come on it and + + align:start position:0% +we put the kit come on it and + + + align:start position:0% +we put the kit come on it and +before it read for us and put the + + align:start position:0% +before it read for us and put the + + + align:start position:0% +before it read for us and put the +critical moment if it's positive in the + + align:start position:0% +critical moment if it's positive in the + + + align:start position:0% +critical moment if it's positive in the +upper side negative at the down side + + align:start position:0% +upper side negative at the down side + + + align:start position:0% +upper side negative at the down side +like the + + align:start position:0% +like the + + + align:start position:0% +like the +the last day the first day can you what + + align:start position:0% +the last day the first day can you what + + + align:start position:0% +the last day the first day can you what +to begin okay can I I suggest you to + + align:start position:0% +to begin okay can I I suggest you to + + + align:start position:0% +to begin okay can I I suggest you to +take your four with you and begin to + + align:start position:0% + + + + align:start position:0% + +Yes um one positive was the exercise + + align:start position:0% +Yes um one positive was the exercise + + + align:start position:0% +Yes um one positive was the exercise +around reframing that the problem + + align:start position:0% +around reframing that the problem + + + align:start position:0% +around reframing that the problem +statement + + align:start position:0% + + + + align:start position:0% + +okay and then + + align:start position:0% +okay and then + + + align:start position:0% +okay and then +um I have to about the same exercise the + + align:start position:0% +um I have to about the same exercise the + + + align:start position:0% +um I have to about the same exercise the +whole reframing exercise + + align:start position:0% + + + + align:start position:0% + +uh and then the assumptions + + align:start position:0% +uh and then the assumptions + + + align:start position:0% +uh and then the assumptions +um this means + + align:start position:0% +um this means + + + align:start position:0% +um this means +the the awareness that was raised of how + + align:start position:0% +the the awareness that was raised of how + + + align:start position:0% +the the awareness that was raised of how +many assumptions I operate from and how + + align:start position:0% +many assumptions I operate from and how + + + align:start position:0% +many assumptions I operate from and how +hard it is to defend + + align:start position:0% + + + + align:start position:0% + +them and then the last one is um the + + align:start position:0% +them and then the last one is um the + + + align:start position:0% +them and then the last one is um the +mental modeling that we did of MIT and + + align:start position:0% +mental modeling that we did of MIT and + + + align:start position:0% +mental modeling that we did of MIT and +the realization of how I can see it + + align:start position:0% +the realization of how I can see it + + + align:start position:0% +the realization of how I can see it +being used to identify areas of conflict + + align:start position:0% +being used to identify areas of conflict + + + align:start position:0% +being used to identify areas of conflict +and agreement + + align:start position:0% +and agreement + + + align:start position:0% +and agreement +okay okay thank you that okay okay + + align:start position:0% +okay okay thank you that okay okay + + + align:start position:0% +okay okay thank you that okay okay +that's okay the this was Tuesday no no + + align:start position:0% +that's okay the this was Tuesday no no + + + align:start position:0% +that's okay the this was Tuesday no no +it the framing the original framing + + align:start position:0% +it the framing the original framing + + + align:start position:0% +it the framing the original framing +exercise was on Monday wasn't it Monday + + align:start position:0% +exercise was on Monday wasn't it Monday + + + align:start position:0% +exercise was on Monday wasn't it Monday +yeah yes okay okay yes yes correct the + + align:start position:0% +yeah yes okay okay yes yes correct the + + + align:start position:0% +yeah yes okay okay yes yes correct the +first exercise was framing okay the next + + align:start position:0% + + + + align:start position:0% + +one + + align:start position:0% + + + + align:start position:0% + +okay describing um mental models as + + align:start position:0% +okay describing um mental models as + + + align:start position:0% +okay describing um mental models as +possible + + align:start position:0% + + + + align:start position:0% + +and identifying features for framing I + + align:start position:0% +and identifying features for framing I + + + align:start position:0% +and identifying features for framing I +very + + align:start position:0% +very + + + align:start position:0% +very +critical day + + align:start position:0% + + + + align:start position:0% + +eight and using assumptions being + + align:start position:0% +eight and using assumptions being + + + align:start position:0% +eight and using assumptions being +careful for writing questions using + + align:start position:0% +careful for writing questions using + + + align:start position:0% +careful for writing questions using +assumptions and your own values that + + align:start position:0% +assumptions and your own values that + + + align:start position:0% +assumptions and your own values that +exercise was + + align:start position:0% + + + + align:start position:0% + +very okay thank you very + + align:start position:0% +very okay thank you very + + + align:start position:0% +very okay thank you very +much another person + + align:start position:0% + + + + align:start position:0% + +walk + + align:start position:0% + + + + align:start position:0% + +off day four um how stuck we are in our + + align:start position:0% +off day four um how stuck we are in our + + + align:start position:0% +off day four um how stuck we are in our +theories of or spoused and theories of + + align:start position:0% +theories of or spoused and theories of + + + align:start position:0% +theories of or spoused and theories of +action same day I had a so what + + align:start position:0% + + + + align:start position:0% + +moment + + align:start position:0% +moment + + + align:start position:0% +moment +um + + align:start position:0% +um + + + align:start position:0% +um +H where's the modeling one the modeling + + align:start position:0% +H where's the modeling one the modeling + + + align:start position:0% +H where's the modeling one the modeling +five + + align:start position:0% +five + + + align:start position:0% +five +I enjoyed MIT model and my moment of + + align:start position:0% +I enjoyed MIT model and my moment of + + + align:start position:0% +I enjoyed MIT model and my moment of +looking at an MIT model as if I were a + + align:start position:0% +looking at an MIT model as if I were a + + + align:start position:0% +looking at an MIT model as if I were a +squirrel or if I were a bird help me + + align:start position:0% +squirrel or if I were a bird help me + + + align:start position:0% +squirrel or if I were a bird help me +give me an AA + + align:start position:0% +give me an AA + + + align:start position:0% +give me an AA +moment you know it's weird that I was + + align:start position:0% +moment you know it's weird that I was + + + align:start position:0% +moment you know it's weird that I was +probably on something that morning um + + align:start position:0% +probably on something that morning um + + + align:start position:0% +probably on something that morning um +and then 10 I guess yesterday yesterday + + align:start position:0% +and then 10 I guess yesterday yesterday + + + align:start position:0% +and then 10 I guess yesterday yesterday +yes um how we can combine some + + align:start position:0% +yes um how we can combine some + + + align:start position:0% +yes um how we can combine some +creativity with rationality ah okay + + align:start position:0% +creativity with rationality ah okay + + + align:start position:0% +creativity with rationality ah okay +thank you + + align:start position:0% +thank you + + + align:start position:0% +thank you +who you + + align:start position:0% + + + + align:start position:0% + +Le's a + + align:start position:0% + + + + align:start position:0% + +tape okay my first one was um the + + align:start position:0% +tape okay my first one was um the + + + align:start position:0% +tape okay my first one was um the +reframing + + align:start position:0% +reframing + + + align:start position:0% +reframing +exercise um the reframing yep which day + + align:start position:0% +exercise um the reframing yep which day + + + align:start position:0% +exercise um the reframing yep which day +was that was day + + align:start position:0% +was that was day + + + align:start position:0% +was that was day +four that was yeah that was that and + + align:start position:0% +four that was yeah that was that and + + + align:start position:0% +four that was yeah that was that and +justice for all my issue was this + + align:start position:0% +justice for all my issue was this + + + align:start position:0% +justice for all my issue was this +exercise + + align:start position:0% +exercise + + + align:start position:0% +exercise +um day + + align:start position:0% +um day + + + align:start position:0% +um day +10 positive uh revisiting concepts with + + align:start position:0% +10 positive uh revisiting concepts with + + + align:start position:0% +10 positive uh revisiting concepts with +reframing a + + align:start position:0% + + + + align:start position:0% + +frame um day + + align:start position:0% + + + + align:start position:0% + +four um again well this is positive um + + align:start position:0% +four um again well this is positive um + + + align:start position:0% +four um again well this is positive um +day for yeah it was after going back and + + align:start position:0% +day for yeah it was after going back and + + + align:start position:0% +day for yeah it was after going back and +thinking about it um being able to + + align:start position:0% +thinking about it um being able to + + + align:start position:0% +thinking about it um being able to +separate the issue from the the purpose + + align:start position:0% +separate the issue from the the purpose + + + align:start position:0% +separate the issue from the the purpose +of the + + align:start position:0% +of the + + + align:start position:0% +of the +workshop um and day five mental + + align:start position:0% + + + + align:start position:0% + +models you know my actualization how I + + align:start position:0% +models you know my actualization how I + + + align:start position:0% +models you know my actualization how I +actually use + + align:start position:0% +actually use + + + align:start position:0% +actually use +MIT my RO here at MIT okay thank you + + align:start position:0% +MIT my RO here at MIT okay thank you + + + align:start position:0% +MIT my RO here at MIT okay thank you +very much I will try to move this + + align:start position:0% +very much I will try to move this + + + align:start position:0% +very much I will try to move this +for able to make + + align:start position:0% + + + + align:start position:0% + +the next + + align:start position:0% + + + + align:start position:0% + +one the first one about the mental + + align:start position:0% +one the first one about the mental + + + align:start position:0% +one the first one about the mental +models class um was actually never clear + + align:start position:0% +models class um was actually never clear + + + align:start position:0% +models class um was actually never clear +to me how you identify and build a + + align:start position:0% +to me how you identify and build a + + + align:start position:0% +to me how you identify and build a +mental + + align:start position:0% +mental + + + align:start position:0% +mental +model yes five + + align:start position:0% +model yes five + + + align:start position:0% +model yes five +for um the conceptualization + + align:start position:0% +for um the conceptualization + + + align:start position:0% +for um the conceptualization +class about related to the reframing it + + align:start position:0% +class about related to the reframing it + + + align:start position:0% +class about related to the reframing it +was + + align:start position:0% +was + + + align:start position:0% +was +actually was yesterday yesterday it was + + align:start position:0% +actually was yesterday yesterday it was + + + align:start position:0% +actually was yesterday yesterday it was +10 I think 10 right yes so it was + + align:start position:0% +10 I think 10 right yes so it was + + + align:start position:0% +10 I think 10 right yes so it was +positive + + align:start position:0% +positive + + + align:start position:0% +positive +um the reframing + + align:start position:0% + + + + align:start position:0% + +class the class the first Monday this + + align:start position:0% +class the class the first Monday this + + + align:start position:0% +class the class the first Monday this +this week Monday yes is actually very + + align:start position:0% +this week Monday yes is actually very + + + align:start position:0% +this week Monday yes is actually very +enlightening also POS the importance of + + align:start position:0% +enlightening also POS the importance of + + + align:start position:0% +enlightening also POS the importance of +refraining yes okay and then I thought + + align:start position:0% +refraining yes okay and then I thought + + + align:start position:0% +refraining yes okay and then I thought +there was not enough reflective dialogue + + align:start position:0% +there was not enough reflective dialogue + + + align:start position:0% +there was not enough reflective dialogue +related to mental + + align:start position:0% + + + + align:start position:0% + +models okay thank you very + + align:start position:0% +models okay thank you very + + + align:start position:0% +models okay thank you very +much + + align:start position:0% +much + + + align:start position:0% +much +okay please + + align:start position:0% +okay please + + + align:start position:0% +okay please +please + + align:start position:0% +please + + + align:start position:0% +please +uh no particular + + align:start position:0% +uh no particular + + + align:start position:0% +uh no particular +order + + align:start position:0% +order + + + align:start position:0% +order +um dissecting assumptions in the problem + + align:start position:0% +um dissecting assumptions in the problem + + + align:start position:0% +um dissecting assumptions in the problem +frame I thought was really helpful + + align:start position:0% +frame I thought was really helpful + + + align:start position:0% +frame I thought was really helpful +exercise um I also thought the framing + + align:start position:0% +exercise um I also thought the framing + + + align:start position:0% +exercise um I also thought the framing +the problem exercise was also very + + align:start position:0% + + + + align:start position:0% + +good no one else mentioned this so far + + align:start position:0% +good no one else mentioned this so far + + + align:start position:0% +good no one else mentioned this so far +but I thought was really + + align:start position:0% + + + + align:start position:0% + +cool help me help me get clear about + + align:start position:0% +cool help me help me get clear about + + + align:start position:0% +cool help me help me get clear about +type of knowledge and how think about + + align:start position:0% +type of knowledge and how think about + + + align:start position:0% +type of knowledge and how think about +issues and s the cycle + + align:start position:0% +issues and s the cycle + + + align:start position:0% +issues and s the cycle +okay yeah and uh I just like hearing + + align:start position:0% +okay yeah and uh I just like hearing + + + align:start position:0% +okay yeah and uh I just like hearing +about Sean's conception of reflective + + align:start position:0% +about Sean's conception of reflective + + + align:start position:0% +about Sean's conception of reflective +practice ah okay thank + + align:start position:0% + + + + align:start position:0% + +you um so none of mine were about the + + align:start position:0% +you um so none of mine were about the + + + align:start position:0% +you um so none of mine were about the +content or the uh exercises they were + + align:start position:0% +content or the uh exercises they were + + + align:start position:0% +content or the uh exercises they were +mostly about + + align:start position:0% +mostly about + + + align:start position:0% +mostly about +just um stuff that got me here and got + + align:start position:0% +just um stuff that got me here and got + + + align:start position:0% +just um stuff that got me here and got +me motivated to be here + + align:start position:0% +me motivated to be here + + + align:start position:0% +me motivated to be here +yes so the first + + align:start position:0% +yes so the first + + + align:start position:0% +yes so the first +um first thing was just seeing the + + align:start position:0% +um first thing was just seeing the + + + align:start position:0% +um first thing was just seeing the +poster of the David + + align:start position:0% +poster of the David + + + align:start position:0% +poster of the David +score remembering that this is something + + align:start position:0% +score remembering that this is something + + + align:start position:0% +score remembering that this is something +I was interested in and that I should + + align:start position:0% +I was interested in and that I should + + + align:start position:0% +I was interested in and that I should +get up in the + + align:start position:0% +get up in the + + + align:start position:0% +get up in the +[Laughter] + + align:start position:0% +[Laughter] + + + align:start position:0% +[Laughter] +morning none of + + align:start position:0% +morning none of + + + align:start position:0% +morning none of +the then the second thing of related was + + align:start position:0% +the then the second thing of related was + + + align:start position:0% +the then the second thing of related was +I was going to do this GIS course and I + + align:start position:0% +I was going to do this GIS course and I + + + align:start position:0% +I was going to do this GIS course and I +was like oh may have to do that too and + + align:start position:0% +was like oh may have to do that too and + + + align:start position:0% +was like oh may have to do that too and +well maybe I can kind of do both and + + align:start position:0% +well maybe I can kind of do both and + + + align:start position:0% +well maybe I can kind of do both and +well you know kind of do an hour of this + + align:start position:0% +well you know kind of do an hour of this + + + align:start position:0% +well you know kind of do an hour of this +and then run off the other class and do + + align:start position:0% +and then run off the other class and do + + + align:start position:0% +and then run off the other class and do +this crazy thing and I was like no this + + align:start position:0% +this crazy thing and I was like no this + + + align:start position:0% +this crazy thing and I was like no this +is more interesting I'm going to skip + + align:start position:0% +is more interesting I'm going to skip + + + align:start position:0% +is more interesting I'm going to skip +the G course this is more important I + + align:start position:0% +the G course this is more important I + + + align:start position:0% +the G course this is more important I +can G + + align:start position:0% +can G + + + align:start position:0% +can G +anytime um which continued throughout + + align:start position:0% +anytime um which continued throughout + + + align:start position:0% +anytime um which continued throughout +the week by the way to the first GIS + + align:start position:0% +the week by the way to the first GIS + + + align:start position:0% +the week by the way to the first GIS +course then there were a number of other + + align:start position:0% +course then there were a number of other + + + align:start position:0% +course then there were a number of other +things that I thought I was going to do + + align:start position:0% +things that I thought I was going to do + + + align:start position:0% +things that I thought I was going to do +instead of this class and then I ended + + align:start position:0% +instead of this class and then I ended + + + align:start position:0% +instead of this class and then I ended +up still coming to every class I was + + align:start position:0% +up still coming to every class I was + + + align:start position:0% +up still coming to every class I was +going to go to New York for a long + + align:start position:0% +going to go to New York for a long + + + align:start position:0% +going to go to New York for a long +weekend that didn't happen no different + + align:start position:0% +weekend that didn't happen no different + + + align:start position:0% +weekend that didn't happen no different +things so that was sort of the first + + align:start position:0% +things so that was sort of the first + + + align:start position:0% +things so that was sort of the first +seed of like well you know this is more + + align:start position:0% +seed of like well you know this is more + + + align:start position:0% +seed of like well you know this is more +important um was that okay uh + + align:start position:0% +important um was that okay uh + + + align:start position:0% +important um was that okay uh +then + + align:start position:0% +then + + + align:start position:0% +then +um uh Claudia and sebastio invited me to + + align:start position:0% +um uh Claudia and sebastio invited me to + + + align:start position:0% +um uh Claudia and sebastio invited me to +come and do the mental mapping exercise + + align:start position:0% +come and do the mental mapping exercise + + + align:start position:0% +come and do the mental mapping exercise +with before class yes and so I learned a + + align:start position:0% +with before class yes and so I learned a + + + align:start position:0% +with before class yes and so I learned a +lot about new ways of thinking about um + + align:start position:0% +lot about new ways of thinking about um + + + align:start position:0% +lot about new ways of thinking about um +cognitive mapping and I just really + + align:start position:0% +cognitive mapping and I just really + + + align:start position:0% +cognitive mapping and I just really +enjoyed that that was really helpful for + + align:start position:0% +enjoyed that that was really helpful for + + + align:start position:0% +enjoyed that that was really helpful for +me just going thinking my own thinking + + align:start position:0% +me just going thinking my own thinking + + + align:start position:0% +me just going thinking my own thinking +the work that I'm involved with and then + + align:start position:0% +the work that I'm involved with and then + + + align:start position:0% +the work that I'm involved with and then +um I met with you guys after class and + + align:start position:0% +um I met with you guys after class and + + + align:start position:0% +um I met with you guys after class and +that was really + + align:start position:0% +that was really + + + align:start position:0% +that was really +um got me excited about stuff on the + + align:start position:0% +um got me excited about stuff on the + + + align:start position:0% +um got me excited about stuff on the +same day okay + + align:start position:0% +same day okay + + + align:start position:0% +same day okay +so just for not + + align:start position:0% +so just for not + + + align:start position:0% +so just for not +block okay let + + align:start position:0% +block okay let + + + align:start position:0% +block okay let +let here we we assume that I connected + + align:start position:0% +let here we we assume that I connected + + + align:start position:0% +let here we we assume that I connected +with okay thank + + align:start position:0% + + + + align:start position:0% + +you so I'm really bad at remembering + + align:start position:0% +you so I'm really bad at remembering + + + align:start position:0% +you so I'm really bad at remembering +like what day it is + + align:start position:0% +like what day it is + + + align:start position:0% +like what day it is +so um you'll have to help me okay + + align:start position:0% +so um you'll have to help me okay + + + align:start position:0% +so um you'll have to help me okay +um I think it was day 10 learning that + + align:start position:0% +um I think it was day 10 learning that + + + align:start position:0% +um I think it was day 10 learning that +um the key is conceptual Innovation and + + align:start position:0% +um the key is conceptual Innovation and + + + align:start position:0% +um the key is conceptual Innovation and +not Technic day 10 day 10 conceptual + + align:start position:0% +not Technic day 10 day 10 conceptual + + + align:start position:0% +not Technic day 10 day 10 conceptual +Innovation and not and not technical + + align:start position:0% +Innovation and not and not technical + + + align:start position:0% +Innovation and not and not technical +Innovation yes + + align:start position:0% +Innovation yes + + + align:start position:0% +Innovation yes +okay um learning that lack of is not a + + align:start position:0% +okay um learning that lack of is not a + + + align:start position:0% +okay um learning that lack of is not a +way to State the + + align:start position:0% + + + + align:start position:0% + +problem + + align:start position:0% +problem + + + align:start position:0% +problem +the of + + align:start position:0% +the of + + + align:start position:0% +the of +money eight eight eight okay positive or + + align:start position:0% +money eight eight eight okay positive or + + + align:start position:0% +money eight eight eight okay positive or +negative + + align:start position:0% +negative + + + align:start position:0% +negative +it was it was positive and negative I + + align:start position:0% +it was it was positive and negative I + + + align:start position:0% +it was it was positive and negative I +was like oh okay it isn't you know so + + align:start position:0% +was like oh okay it isn't you know so + + + align:start position:0% +was like oh okay it isn't you know so +that was kind of negative CU I always + + align:start position:0% +that was kind of negative CU I always + + + align:start position:0% +that was kind of negative CU I always +just thought like I knew had a state of + + align:start position:0% +just thought like I knew had a state of + + + align:start position:0% +just thought like I knew had a state of +problem you + + align:start position:0% +problem you + + + align:start position:0% +problem you +know had a lot of lack of problem + + align:start position:0% +know had a lot of lack of problem + + + align:start position:0% +know had a lot of lack of problem +state but um but it was positive because + + align:start position:0% +state but um but it was positive because + + + align:start position:0% +state but um but it was positive because +now it forces me to think more you know + + align:start position:0% +now it forces me to think more you know + + + align:start position:0% +now it forces me to think more you know +when someone says what's the problem + + align:start position:0% +when someone says what's the problem + + + align:start position:0% +when someone says what's the problem +here now I have to think more so it was + + align:start position:0% +here now I have to think more so it was + + + align:start position:0% +here now I have to think more so it was +good kind + + align:start position:0% + + + + align:start position:0% + +of um and then I like when um Cesar was + + align:start position:0% +of um and then I like when um Cesar was + + + align:start position:0% +of um and then I like when um Cesar was +telling us the story about + + align:start position:0% +telling us the story about + + + align:start position:0% +telling us the story about +Framingham the + + align:start position:0% +Framingham the + + + align:start position:0% +Framingham the +first + + align:start position:0% + + + + align:start position:0% + +sevening about fing when told us the + + align:start position:0% +sevening about fing when told us the + + + align:start position:0% +sevening about fing when told us the +story 77 Monday 7 for he told the story + + align:start position:0% +story 77 Monday 7 for he told the story + + + align:start position:0% +story 77 Monday 7 for he told the story +for helping us to frame the situation of + + align:start position:0% +for helping us to frame the situation of + + + align:start position:0% +for helping us to frame the situation of +Framingham okay um you know I thought + + align:start position:0% +Framingham okay um you know I thought + + + align:start position:0% +Framingham okay um you know I thought +that was positive and negative like it + + align:start position:0% +that was positive and negative like it + + + align:start position:0% +that was positive and negative like it +was positive because I felt like I + + align:start position:0% +was positive because I felt like I + + + align:start position:0% +was positive because I felt like I +learned a lot about the situation and + + align:start position:0% +learned a lot about the situation and + + + align:start position:0% +learned a lot about the situation and +what went on and it was kind of negative + + align:start position:0% +what went on and it was kind of negative + + + align:start position:0% +what went on and it was kind of negative +cuz and I thought oh my gosh like these + + align:start position:0% +cuz and I thought oh my gosh like these + + + align:start position:0% +cuz and I thought oh my gosh like these +are some of the challenges and issues + + align:start position:0% +are some of the challenges and issues + + + align:start position:0% +are some of the challenges and issues +that I'm going to have to deal with like + + align:start position:0% +that I'm going to have to deal with like + + + align:start position:0% +that I'm going to have to deal with like +as a planner and + + align:start position:0% +as a planner and + + + align:start position:0% +as a planner and +so um and + + align:start position:0% +so um and + + + align:start position:0% +so um and +then the day um having the class disturb + + align:start position:0% +then the day um having the class disturb + + + align:start position:0% +then the day um having the class disturb +my assumptions when they question me on + + align:start position:0% +my assumptions when they question me on + + + align:start position:0% +my assumptions when they question me on +the race + + align:start position:0% + + + + align:start position:0% + +exercise great that was four four so + + align:start position:0% +exercise great that was four four so + + + align:start position:0% +exercise great that was four four so +that was actually it started off as a + + align:start position:0% +that was actually it started off as a + + + align:start position:0% +that was actually it started off as a +negative CU I was like what are you + + align:start position:0% +negative CU I was like what are you + + + align:start position:0% +negative CU I was like what are you +doing like why are you you know I I + + align:start position:0% +doing like why are you you know I I + + + align:start position:0% +doing like why are you you know I I +don't I didn't really understand yeah + + align:start position:0% +don't I didn't really understand yeah + + + align:start position:0% +don't I didn't really understand yeah +you know as yet like what really the + + align:start position:0% +you know as yet like what really the + + + align:start position:0% +you know as yet like what really the +point of it was and so you get kind of + + align:start position:0% +point of it was and so you get kind of + + + align:start position:0% +point of it was and so you get kind of +defensive and like you have to like + + align:start position:0% +defensive and like you have to like + + + align:start position:0% +defensive and like you have to like +defend what you're saying but I mean now + + align:start position:0% +defend what you're saying but I mean now + + + align:start position:0% +defend what you're saying but I mean now +I think it's positive because I realize + + align:start position:0% +I think it's positive because I realize + + + align:start position:0% +I think it's positive because I realize +like it was you know this whole process + + align:start position:0% +like it was you know this whole process + + + align:start position:0% +like it was you know this whole process +of just uncovering our assumptions which + + align:start position:0% +of just uncovering our assumptions which + + + align:start position:0% +of just uncovering our assumptions which +I now see is a good thing we don't have + + align:start position:0% +I now see is a good thing we don't have + + + align:start position:0% +I now see is a good thing we don't have +to hold on + + align:start position:0% +to hold on + + + align:start position:0% +to hold on +okay we are oh + + align:start position:0% +okay we are oh + + + align:start position:0% +okay we are oh +you but what I try to do in the back + + align:start position:0% +you but what I try to do in the back + + + align:start position:0% +you but what I try to do in the back +which you will see later I I don't know + + align:start position:0% +which you will see later I I don't know + + + align:start position:0% +which you will see later I I don't know +if I remember the + + align:start position:0% +if I remember the + + + align:start position:0% +if I remember the +days + + align:start position:0% +days + + + align:start position:0% +days +but first I start with reflex and PR + + align:start position:0% +but first I start with reflex and PR + + + align:start position:0% +but first I start with reflex and PR +because I was not I had one idea about + + align:start position:0% +because I was not I had one idea about + + + align:start position:0% +because I was not I had one idea about +it and then when I got here and started + + align:start position:0% +it and then when I got here and started + + + align:start position:0% +it and then when I got here and started +to see it I was like I had to completely + + align:start position:0% +to see it I was like I had to completely + + + align:start position:0% +to see it I was like I had to completely +change my way of thinking what + + align:start position:0% +change my way of thinking what + + + align:start position:0% +change my way of thinking what +reflecting practice of you was so the + + align:start position:0% +reflecting practice of you was so the + + + align:start position:0% +reflecting practice of you was so the +positive is on the + + align:start position:0% +positive is on the + + + align:start position:0% +positive is on the +top okay when did you realize that + + align:start position:0% +top okay when did you realize that + + + align:start position:0% +top okay when did you realize that +yesterday no I think was a process was + + align:start position:0% +yesterday no I think was a process was + + + align:start position:0% +yesterday no I think was a process was +throughout the course and I felt every I + + align:start position:0% +throughout the course and I felt every I + + + align:start position:0% +throughout the course and I felt every I +was learning different you know in the + + align:start position:0% +was learning different you know in the + + + align:start position:0% +was learning different you know in the +process and then on the back I put a + + align:start position:0% +process and then on the back I put a + + + align:start position:0% +process and then on the back I put a +little bit about what was happening + + align:start position:0% +little bit about what was happening + + + align:start position:0% +little bit about what was happening +around that time and my community from + + align:start position:0% +around that time and my community from + + + align:start position:0% +around that time and my community from +him is what was discussing that was + + align:start position:0% +him is what was discussing that was + + + align:start position:0% +him is what was discussing that was +making me thinking of that so you can + + align:start position:0% +making me thinking of that so you can + + + align:start position:0% +making me thinking of that so you can +see that later uh and then I found the + + align:start position:0% +see that later uh and then I found the + + + align:start position:0% +see that later uh and then I found the +frame and reframe the and of course the + + align:start position:0% +frame and reframe the and of course the + + + align:start position:0% +frame and reframe the and of course the +frame and reframe was really what helped + + align:start position:0% +frame and reframe was really what helped + + + align:start position:0% +frame and reframe was really what helped +me to see what the reflection practicing + + align:start position:0% +me to see what the reflection practicing + + + align:start position:0% +me to see what the reflection practicing +was wasse because to trying to do the + + align:start position:0% +was wasse because to trying to do the + + + align:start position:0% +was wasse because to trying to do the +frame and reframe was when I could + + align:start position:0% +frame and reframe was when I could + + + align:start position:0% +frame and reframe was when I could +better understand what reflection to was + + align:start position:0% +better understand what reflection to was + + + align:start position:0% +better understand what reflection to was +does that make sense to you yes which + + align:start position:0% +does that make sense to you yes which + + + align:start position:0% +does that make sense to you yes which +day the day when we we we did a refra I + + align:start position:0% +day the day when we we we did a refra I + + + align:start position:0% +day the day when we we we did a refra I +think was it started on Monday that + + align:start position:0% +think was it started on Monday that + + + align:start position:0% +think was it started on Monday that +would really get into small what day was + + align:start position:0% +would really get into small what day was + + + align:start position:0% +would really get into small what day was +that Monday is here this is Monday it's + + align:start position:0% +that Monday is here this is Monday it's + + + align:start position:0% +that Monday is here this is Monday it's +positive or negative it's positive okay + + align:start position:0% +positive or negative it's positive okay + + + align:start position:0% +positive or negative it's positive okay +let's put I'm a own + + align:start position:0% +let's put I'm a own + + + align:start position:0% +let's put I'm a own +positive okay but actually the framing + + align:start position:0% +positive okay but actually the framing + + + align:start position:0% +positive okay but actually the framing +for her was + + align:start position:0% +for her was + + + align:start position:0% +for her was +Tuesday she was a listen she put Framing + + align:start position:0% +Tuesday she was a listen she put Framing + + + align:start position:0% +Tuesday she was a listen she put Framing +and reframing you need to + + align:start position:0% +and reframing you need to + + + align:start position:0% +and reframing you need to +choose okay uh Tuesday right Tuesday + + align:start position:0% +choose okay uh Tuesday right Tuesday + + + align:start position:0% +choose okay uh Tuesday right Tuesday +Tuesday was the when I we could size we + + align:start position:0% +Tuesday was the when I we could size we + + + align:start position:0% +Tuesday was the when I we could size we +analyze we analyze the framewor the + + align:start position:0% +analyze we analyze the framewor the + + + align:start position:0% +analyze we analyze the framewor the +frame it was Tuesday and we discover how + + align:start position:0% +frame it was Tuesday and we discover how + + + align:start position:0% +frame it was Tuesday and we discover how +it was stated how if the assumptions + + align:start position:0% +it was stated how if the assumptions + + + align:start position:0% +it was stated how if the assumptions +really were MH and the question of the + + align:start position:0% +really were MH and the question of the + + + align:start position:0% +really were MH and the question of the +lack of mhm no so that's Tuesday right + + align:start position:0% +lack of mhm no so that's Tuesday right + + + align:start position:0% +lack of mhm no so that's Tuesday right +Tu + + align:start position:0% +Tu + + + align:start position:0% +Tu +here and then Wednesday was when when we + + align:start position:0% +here and then Wednesday was when when we + + + align:start position:0% +here and then Wednesday was when when we +were looking at + + align:start position:0% +were looking at + + + align:start position:0% +were looking at +how coherent the models the frames okay + + align:start position:0% +how coherent the models the frames okay + + + align:start position:0% +how coherent the models the frames okay +I think that was the mental models and + + align:start position:0% +I think that was the mental models and + + + align:start position:0% +I think that was the mental models and +dialogue that was less so the theories + + align:start position:0% +dialogue that was less so the theories + + + align:start position:0% +dialogue that was less so the theories +in the concept of the ideas I think I + + align:start position:0% +in the concept of the ideas I think I + + + align:start position:0% +in the concept of the ideas I think I +got when I understood the frame and + + align:start position:0% +got when I understood the frame and + + + align:start position:0% +got when I understood the frame and +reframe was when I really could see the + + align:start position:0% +reframe was when I really could see the + + + align:start position:0% +reframe was when I really could see the +concept of the ideas and things coming + + align:start position:0% +concept of the ideas and things coming + + + align:start position:0% +concept of the ideas and things coming +together and I and I I think I'm very + + align:start position:0% +together and I and I I think I'm very + + + align:start position:0% +together and I and I I think I'm very +visual because I was really using this + + align:start position:0% +visual because I was really using this + + + align:start position:0% +visual because I was really using this +models that was learning here is the + + align:start position:0% +models that was learning here is the + + + align:start position:0% +models that was learning here is the +work I was doing in but I put it in the + + align:start position:0% +work I was doing in but I put it in the + + + align:start position:0% +work I was doing in but I put it in the +back of here you can take a look and I + + align:start position:0% +back of here you can take a look and I + + + align:start position:0% +back of here you can take a look and I +think I had a better understand it was + + align:start position:0% +think I had a better understand it was + + + align:start position:0% +think I had a better understand it was +more positive than it was negative when + + align:start position:0% +more positive than it was negative when + + + align:start position:0% +more positive than it was negative when +I was watching when I was here thinking + + align:start position:0% +I was watching when I was here thinking + + + align:start position:0% +I was watching when I was here thinking +I didn't feel as positive when I had to + + align:start position:0% +I didn't feel as positive when I had to + + + align:start position:0% +I didn't feel as positive when I had to +implement in a community so that was on + + align:start position:0% +implement in a community so that was on + + + align:start position:0% +implement in a community so that was on +Thursday + + align:start position:0% +Thursday + + + align:start position:0% +Thursday +Thursday yes here this + + align:start position:0% + + + + align:start position:0% + +night + + align:start position:0% + + + + align:start position:0% + +okay and the ment Mar I think that was + + align:start position:0% +okay and the ment Mar I think that was + + + align:start position:0% +okay and the ment Mar I think that was +before the mental Mar and the difficult + + align:start position:0% +before the mental Mar and the difficult + + + align:start position:0% +before the mental Mar and the difficult +of the dialogue and to put in the St + + align:start position:0% +of the dialogue and to put in the St + + + align:start position:0% +of the dialogue and to put in the St +together that was very I really still + + align:start position:0% +together that was very I really still + + + align:start position:0% +together that was very I really still +not quite get that okay what is the + + align:start position:0% +not quite get that okay what is the + + + align:start position:0% +not quite get that okay what is the +mental model was I think that + + align:start position:0% +mental model was I think that + + + align:start position:0% +mental model was I think that +was five it's negative yeah okay okay + + align:start position:0% +was five it's negative yeah okay okay + + + align:start position:0% +was five it's negative yeah okay okay +thank you very much let's move it a bit + + align:start position:0% +thank you very much let's move it a bit + + + align:start position:0% +thank you very much let's move it a bit +for not to block the other one + + align:start position:0% +for not to block the other one + + + align:start position:0% +for not to block the other one +okay so we have here a brief description + + align:start position:0% +okay so we have here a brief description + + + align:start position:0% +okay so we have here a brief description +a very brief description of what + + align:start position:0% +a very brief description of what + + + align:start position:0% +a very brief description of what +happened + + align:start position:0% +happened + + + align:start position:0% +happened +what I would like to talk with you is + + align:start position:0% +what I would like to talk with you is + + + align:start position:0% +what I would like to talk with you is +can I sit + + align:start position:0% + + + + align:start position:0% + +here + + align:start position:0% +here + + + align:start position:0% +here +okay thank + + align:start position:0% +okay thank + + + align:start position:0% +okay thank +you because if I I'm there I will be + + align:start position:0% +you because if I I'm there I will be + + + align:start position:0% +you because if I I'm there I will be +blocking you okay let's + + align:start position:0% +blocking you okay let's + + + align:start position:0% +blocking you okay let's +see + + align:start position:0% + + + + align:start position:0% + +first + + align:start position:0% +first + + + align:start position:0% +first +ER we have the perceptions of all the + + align:start position:0% +ER we have the perceptions of all the + + + align:start position:0% +ER we have the perceptions of all the +participants during the course + + align:start position:0% +participants during the course + + + align:start position:0% +participants during the course +what are the + + align:start position:0% + + + + align:start position:0% + +main the mean find this what are you + + align:start position:0% +main the mean find this what are you + + + align:start position:0% +main the mean find this what are you +seeing in + + align:start position:0% +seeing in + + + align:start position:0% +seeing in +this what can you see in this group of + + align:start position:0% +this what can you see in this group of + + + align:start position:0% +this what can you see in this group of +critical + + align:start position:0% +critical + + + align:start position:0% +critical +moments yes it it seems like to me that + + align:start position:0% +moments yes it it seems like to me that + + + align:start position:0% +moments yes it it seems like to me that +uh people rated the the highest um + + align:start position:0% +uh people rated the the highest um + + + align:start position:0% +uh people rated the the highest um +things that + + align:start position:0% +things that + + + align:start position:0% +things that +were of particular relevance to them + + align:start position:0% +were of particular relevance to them + + + align:start position:0% +were of particular relevance to them +um in their work so like for me the + + align:start position:0% +um in their work so like for me the + + + align:start position:0% +um in their work so like for me the +mental mapping was really important just + + align:start position:0% +mental mapping was really important just + + + align:start position:0% +mental mapping was really important just +in terms of what I what I've been doing + + align:start position:0% +in terms of what I what I've been doing + + + align:start position:0% +in terms of what I what I've been doing +for my research and I think for a lot of + + align:start position:0% +for my research and I think for a lot of + + + align:start position:0% +for my research and I think for a lot of +people throughout the course I keep + + align:start position:0% +people throughout the course I keep + + + align:start position:0% +people throughout the course I keep +hearing that reframing is something that + + align:start position:0% +hearing that reframing is something that + + + align:start position:0% +hearing that reframing is something that +people are interested in and so it's not + + align:start position:0% +people are interested in and so it's not + + + align:start position:0% +people are interested in and so it's not +terribly surprising to me that a lot of + + align:start position:0% +terribly surprising to me that a lot of + + + align:start position:0% +terribly surprising to me that a lot of +people really congregated around the + + align:start position:0% +people really congregated around the + + + align:start position:0% +people really congregated around the +reframing exercise as being the most + + align:start position:0% +reframing exercise as being the most + + + align:start position:0% +reframing exercise as being the most +important part because it's something + + align:start position:0% +important part because it's something + + + align:start position:0% +important part because it's something +that they already felt was valuable and + + align:start position:0% +that they already felt was valuable and + + + align:start position:0% +that they already felt was valuable and +necessary for their work and I feel like + + align:start position:0% +necessary for their work and I feel like + + + align:start position:0% +necessary for their work and I feel like +the negative ones are largely when + + align:start position:0% +the negative ones are largely when + + + align:start position:0% +the negative ones are largely when +people weren't quite + + align:start position:0% +people weren't quite + + + align:start position:0% +people weren't quite +understanding why why to do the exercise + + align:start position:0% +understanding why why to do the exercise + + + align:start position:0% +understanding why why to do the exercise +or or what the concept was that they + + align:start position:0% +or or what the concept was that they + + + align:start position:0% +or or what the concept was that they +were supposed to be getting it's when + + align:start position:0% +were supposed to be getting it's when + + + align:start position:0% +were supposed to be getting it's when +there was some confusion or a sense of + + align:start position:0% +there was some confusion or a sense of + + + align:start position:0% +there was some confusion or a sense of +um that they weren't like they weren't + + align:start position:0% +um that they weren't like they weren't + + + align:start position:0% +um that they weren't like they weren't +getting the material perhaps but those + + align:start position:0% +getting the material perhaps but those + + + align:start position:0% +getting the material perhaps but those +seem like maybe a lot of the + + align:start position:0% +seem like maybe a lot of the + + + align:start position:0% +seem like maybe a lot of the +problems okay thank you another + + align:start position:0% + + + + align:start position:0% + +comment + + align:start position:0% +comment + + + align:start position:0% +comment +yes uh it seems like the turning point + + align:start position:0% +yes uh it seems like the turning point + + + align:start position:0% +yes uh it seems like the turning point +for people was the end of last week in + + align:start position:0% +for people was the end of last week in + + + align:start position:0% +for people was the end of last week in +the beginning of the second week because + + align:start position:0% +the beginning of the second week because + + + align:start position:0% +the beginning of the second week because +there's a lot of a lot of negative but + + align:start position:0% +there's a lot of a lot of negative but + + + align:start position:0% +there's a lot of a lot of negative but +also a lot of positive within that that + + align:start position:0% +also a lot of positive within that that + + + align:start position:0% +also a lot of positive within that that +frame of time between Friday and Monday + + align:start position:0% +frame of time between Friday and Monday + + + align:start position:0% +frame of time between Friday and Monday +I mean the beginning of the second week + + align:start position:0% +I mean the beginning of the second week + + + align:start position:0% +I mean the beginning of the second week +I think it's an + + align:start position:0% +I think it's an + + + align:start position:0% +I think it's an +important um + + align:start position:0% +important um + + + align:start position:0% +important um +mhm there there was an important change + + align:start position:0% +mhm there there was an important change + + + align:start position:0% +mhm there there was an important change +within people's identification of + + align:start position:0% +within people's identification of + + + align:start position:0% +within people's identification of +critical moments either if they are + + align:start position:0% +critical moments either if they are + + + align:start position:0% +critical moments either if they are +positive or negative mhm building on + + align:start position:0% +positive or negative mhm building on + + + align:start position:0% +positive or negative mhm building on +that point it seems like the first first + + align:start position:0% +that point it seems like the first first + + + align:start position:0% +that point it seems like the first first +couple of days people kind of maybe + + align:start position:0% +couple of days people kind of maybe + + + align:start position:0% +couple of days people kind of maybe +weren't getting it or everyone's kind of + + align:start position:0% +weren't getting it or everyone's kind of + + + align:start position:0% +weren't getting it or everyone's kind of +getting their feet wet slow sorry the + + align:start position:0% +getting their feet wet slow sorry the + + + align:start position:0% +getting their feet wet slow sorry the +first couple of days everyone sort of + + align:start position:0% +first couple of days everyone sort of + + + align:start position:0% +first couple of days everyone sort of +starting to get their feet wet and you + + align:start position:0% +starting to get their feet wet and you + + + align:start position:0% +starting to get their feet wet and you +know they're sort of just trying to + + align:start position:0% +know they're sort of just trying to + + + align:start position:0% +know they're sort of just trying to +figure stuff out and then we started to + + align:start position:0% +figure stuff out and then we started to + + + align:start position:0% +figure stuff out and then we started to +employ it on the fourth and fifth day + + align:start position:0% +employ it on the fourth and fifth day + + + align:start position:0% +employ it on the fourth and fifth day +and people sort of struggled with that + + align:start position:0% +and people sort of struggled with that + + + align:start position:0% +and people sort of struggled with that +and had a hard time so we had a mix of + + align:start position:0% +and had a hard time so we had a mix of + + + align:start position:0% +and had a hard time so we had a mix of +reactions but then in the second week + + align:start position:0% +reactions but then in the second week + + + align:start position:0% +reactions but then in the second week +maybe people started to come together + + align:start position:0% +maybe people started to come together + + + align:start position:0% +maybe people started to come together +and understand better and really kind of + + align:start position:0% +and understand better and really kind of + + + align:start position:0% +and understand better and really kind of +get it at a deeper Lev maybe which then + + align:start position:0% +get it at a deeper Lev maybe which then + + + align:start position:0% +get it at a deeper Lev maybe which then +made it make more sense okay thank + + align:start position:0% +made it make more sense okay thank + + + align:start position:0% +made it make more sense okay thank +you other + + align:start position:0% + + + + align:start position:0% + +comment if you want we can compare your + + align:start position:0% +comment if you want we can compare your + + + align:start position:0% +comment if you want we can compare your +own experience with the experience of + + align:start position:0% +own experience with the experience of + + + align:start position:0% +own experience with the experience of +the + + align:start position:0% + + + + align:start position:0% + +group you + + align:start position:0% +group you + + + align:start position:0% +group you +can talk about surprises you have + + align:start position:0% +can talk about surprises you have + + + align:start position:0% +can talk about surprises you have +looking + + align:start position:0% +looking + + + align:start position:0% +looking +this distribution of critical moments + + align:start position:0% + + + + align:start position:0% + +or question you have in our minds Esra I + + align:start position:0% +or question you have in our minds Esra I + + + align:start position:0% +or question you have in our minds Esra I +was just wondering how much um + + align:start position:0% +was just wondering how much um + + + align:start position:0% +was just wondering how much um +background of other things that are + + align:start position:0% +background of other things that are + + + align:start position:0% +background of other things that are +going on our lives that's where we put + + align:start position:0% +going on our lives that's where we put + + + align:start position:0% +going on our lives that's where we put +critical moments and how we we can talk + + align:start position:0% +critical moments and how we we can talk + + + align:start position:0% +critical moments and how we we can talk +about this later because it should open + + align:start position:0% +about this later because it should open + + + align:start position:0% +about this later because it should open +a new vein of conversation okay let's + + align:start position:0% +a new vein of conversation okay let's + + + align:start position:0% +a new vein of conversation okay let's +see just the course this + + align:start position:0% +see just the course this + + + align:start position:0% +see just the course this +moment how we live live the course yes + + align:start position:0% +moment how we live live the course yes + + + align:start position:0% +moment how we live live the course yes +Rec confirms what I had seen SE in the + + align:start position:0% +Rec confirms what I had seen SE in the + + + align:start position:0% +Rec confirms what I had seen SE in the +other critical moments exercise that we + + align:start position:0% +other critical moments exercise that we + + + align:start position:0% +other critical moments exercise that we +did and the one that was done at at care + + align:start position:0% +did and the one that was done at at care + + + align:start position:0% +did and the one that was done at at care +that the groups critical moments tend to + + align:start position:0% +that the groups critical moments tend to + + + align:start position:0% +that the groups critical moments tend to +Cluster in the same areas it's still + + align:start position:0% +Cluster in the same areas it's still + + + align:start position:0% +Cluster in the same areas it's still +interesting to me that you know working + + align:start position:0% +interesting to me that you know working + + + align:start position:0% +interesting to me that you know working +totally independently that it comes out + + align:start position:0% +totally independently that it comes out + + + align:start position:0% +totally independently that it comes out +that way and now it's it's still 100% of + + align:start position:0% +that way and now it's it's still 100% of + + + align:start position:0% +that way and now it's it's still 100% of +of the three little experiences I've + + align:start position:0% + + + + align:start position:0% + +had okay + + align:start position:0% + + + + align:start position:0% + +yes yes yes thank you about I agree with + + align:start position:0% +yes yes yes thank you about I agree with + + + align:start position:0% +yes yes yes thank you about I agree with +was Chris said we were just trying to + + align:start position:0% +was Chris said we were just trying to + + + align:start position:0% +was Chris said we were just trying to +understand what was going + + align:start position:0% +understand what was going + + + align:start position:0% +understand what was going +on I I think it also relates to when we + + align:start position:0% +on I I think it also relates to when we + + + align:start position:0% +on I I think it also relates to when we +began to do more + + align:start position:0% +began to do more + + + align:start position:0% +began to do more +involved + + align:start position:0% +involved + + + align:start position:0% +involved +um involving exercises where we all + + align:start position:0% +um involving exercises where we all + + + align:start position:0% +um involving exercises where we all +participated at a greater and had a + + align:start position:0% +participated at a greater and had a + + + align:start position:0% +participated at a greater and had a +little bit more indepth discussions + + align:start position:0% +little bit more indepth discussions + + + align:start position:0% +little bit more indepth discussions +about what we were doing it involved us + + align:start position:0% +about what we were doing it involved us + + + align:start position:0% +about what we were doing it involved us +more therefore my assumption would be + + align:start position:0% +more therefore my assumption would be + + + align:start position:0% +more therefore my assumption would be +that that what caused those to be a + + align:start position:0% +that that what caused those to be a + + + align:start position:0% +that that what caused those to be a +little bit more critical okay at the + + align:start position:0% +little bit more critical okay at the + + + align:start position:0% +little bit more critical okay at the +when at the outset I didn't feel very + + align:start position:0% +when at the outset I didn't feel very + + + align:start position:0% +when at the outset I didn't feel very +involved okay and I'm realizing that I + + align:start position:0% +involved okay and I'm realizing that I + + + align:start position:0% +involved okay and I'm realizing that I +made my my critical moments were more + + align:start position:0% +made my my critical moments were more + + + align:start position:0% +made my my critical moments were more +like aha positives but perhaps I should + + align:start position:0% +like aha positives but perhaps I should + + + align:start position:0% +like aha positives but perhaps I should +have put one that went the the whole + + align:start position:0% +have put one that went the the whole + + + align:start position:0% +have put one that went the the whole +length because I still felt that we + + align:start position:0% +length because I still felt that we + + + align:start position:0% +length because I still felt that we +missed opportunities to to do what we + + align:start position:0% +missed opportunities to to do what we + + + align:start position:0% +missed opportunities to to do what we +did yesterday and have a group + + align:start position:0% +did yesterday and have a group + + + align:start position:0% +did yesterday and have a group +discussion where others could say how it + + align:start position:0% +discussion where others could say how it + + + align:start position:0% +discussion where others could say how it +would how they were thinking about it in + + align:start position:0% +would how they were thinking about it in + + + align:start position:0% +would how they were thinking about it in +their own + + align:start position:0% + + + + align:start position:0% + +lives + + align:start position:0% +lives + + + align:start position:0% +lives +okay she + + align:start position:0% +okay she + + + align:start position:0% +okay she +after I totally agree with her is when + + align:start position:0% +after I totally agree with her is when + + + align:start position:0% +after I totally agree with her is when +we I agree with her because that + + align:start position:0% +we I agree with her because that + + + align:start position:0% +we I agree with her because that +particular time Friday was the first day + + align:start position:0% +particular time Friday was the first day + + + align:start position:0% +particular time Friday was the first day +and you had um breakout groups and we + + align:start position:0% +and you had um breakout groups and we + + + align:start position:0% +and you had um breakout groups and we +had a lot of discussion and a lot of + + align:start position:0% +had a lot of discussion and a lot of + + + align:start position:0% +had a lot of discussion and a lot of +interaction that Friday and Monday and I + + align:start position:0% +interaction that Friday and Monday and I + + + align:start position:0% +interaction that Friday and Monday and I +think that touched on that's what most + + align:start position:0% +think that touched on that's what most + + + align:start position:0% +think that touched on that's what most +of us really remember and I think um + + align:start position:0% +of us really remember and I think um + + + align:start position:0% +of us really remember and I think um +Tuesday we also had a break out we have + + align:start position:0% +Tuesday we also had a break out we have + + + align:start position:0% +Tuesday we also had a break out we have +groups exercises we all + + align:start position:0% +groups exercises we all + + + align:start position:0% +groups exercises we all +interacted back and shared deers and um + + align:start position:0% +interacted back and shared deers and um + + + align:start position:0% +interacted back and shared deers and um +I know that's what goes in the moment + + align:start position:0% +I know that's what goes in the moment + + + align:start position:0% +I know that's what goes in the moment +particular days okay thank you yes es uh + + align:start position:0% +particular days okay thank you yes es uh + + + align:start position:0% +particular days okay thank you yes es uh +I was just going to say that it seems + + align:start position:0% +I was just going to say that it seems + + + align:start position:0% +I was just going to say that it seems +like the days that people remember the + + align:start position:0% +like the days that people remember the + + + align:start position:0% +like the days that people remember the +most are also at least in my + + align:start position:0% +most are also at least in my + + + align:start position:0% +most are also at least in my +recollection of the two weeks those were + + align:start position:0% +recollection of the two weeks those were + + + align:start position:0% +recollection of the two weeks those were +the days where we really dug in deepest + + align:start position:0% +the days where we really dug in deepest + + + align:start position:0% +the days where we really dug in deepest +with the exercises and really tried + + align:start position:0% +with the exercises and really tried + + + align:start position:0% +with the exercises and really tried +tried to pull out the + + align:start position:0% +tried to pull out the + + + align:start position:0% +tried to pull out the +assumptions but what is interesting is + + align:start position:0% +assumptions but what is interesting is + + + align:start position:0% +assumptions but what is interesting is +that at the at the beginning when the + + align:start position:0% +that at the at the beginning when the + + + align:start position:0% +that at the at the beginning when the +exercise require by + + align:start position:0% +exercise require by + + + align:start position:0% +exercise require by +more involvement engagement of each one + + align:start position:0% +more involvement engagement of each one + + + align:start position:0% +more involvement engagement of each one +we have more negative critical moments + + align:start position:0% +we have more negative critical moments + + + align:start position:0% +we have more negative critical moments +no and after a + + align:start position:0% +no and after a + + + align:start position:0% +no and after a +while know people got + + align:start position:0% +while know people got + + + align:start position:0% +while know people got +to I think + + align:start position:0% +to I think + + + align:start position:0% +to I think +to control better their I think that + + align:start position:0% +to control better their I think that + + + align:start position:0% +to control better their I think that +also has to do with how people interact + + align:start position:0% +also has to do with how people interact + + + align:start position:0% +also has to do with how people interact +with each other within a group how they + + align:start position:0% +with each other within a group how they + + + align:start position:0% +with each other within a group how they +get to meet each other and be more + + align:start position:0% +get to meet each other and be more + + + align:start position:0% +get to meet each other and be more +comfortable with each other so there's a + + align:start position:0% +comfortable with each other so there's a + + + align:start position:0% +comfortable with each other so there's a +period of time where for the adapation + + align:start position:0% +period of time where for the adapation + + + align:start position:0% +period of time where for the adapation +process implicates positive and negative + + align:start position:0% +process implicates positive and negative + + + align:start position:0% +process implicates positive and negative +effects and that is a consequence of + + align:start position:0% +effects and that is a consequence of + + + align:start position:0% +effects and that is a consequence of +being more aware of the group and of the + + align:start position:0% +being more aware of the group and of the + + + align:start position:0% +being more aware of the group and of the +people and how they think and how you + + align:start position:0% +people and how they think and how you + + + align:start position:0% +people and how they think and how you +have to relate with + + align:start position:0% +have to relate with + + + align:start position:0% +have to relate with +them so I think that's why that can + + align:start position:0% +them so I think that's why that can + + + align:start position:0% +them so I think that's why that can +explain a lot about the negative + + align:start position:0% + + + + align:start position:0% + +also but the the critical moment that + + align:start position:0% +also but the the critical moment that + + + align:start position:0% +also but the the critical moment that +don't refer to + + align:start position:0% +don't refer to + + + align:start position:0% +don't refer to +group relation they refer to relation + + align:start position:0% +group relation they refer to relation + + + align:start position:0% +group relation they refer to relation +between the person and some issues of + + align:start position:0% +between the person and some issues of + + + align:start position:0% +between the person and some issues of +the course no no no because if + + align:start position:0% +the course no no no because if + + + align:start position:0% +the course no no no because if +you I + + align:start position:0% +you I + + + align:start position:0% +you I +mean if you know you're stuck you're + + align:start position:0% +mean if you know you're stuck you're + + + align:start position:0% +mean if you know you're stuck you're +feeling stuck in certain situations and + + align:start position:0% +feeling stuck in certain situations and + + + align:start position:0% +feeling stuck in certain situations and +it may be related to your inability to + + align:start position:0% +it may be related to your inability to + + + align:start position:0% +it may be related to your inability to +connect to the other people in your + + align:start position:0% +connect to the other people in your + + + align:start position:0% +connect to the other people in your +group with whom you're doing an exercise + + align:start position:0% +group with whom you're doing an exercise + + + align:start position:0% +group with whom you're doing an exercise +you + + align:start position:0% + + + + align:start position:0% + +know how comfortable you + + align:start position:0% +know how comfortable you + + + align:start position:0% +know how comfortable you +feel okay should be an explanation but + + align:start position:0% +feel okay should be an explanation but + + + align:start position:0% +feel okay should be an explanation but +not stated there in the words well yeah + + align:start position:0% +not stated there in the words well yeah + + + align:start position:0% +not stated there in the words well yeah +agreed + + align:start position:0% +agreed + + + align:start position:0% +agreed +that my + + align:start position:0% +that my + + + align:start position:0% +that my +reasons part of my + + align:start position:0% +reasons part of my + + + align:start position:0% +reasons part of my +reasons I I think that I began to have + + align:start position:0% +reasons I I think that I began to have + + + align:start position:0% +reasons I I think that I began to have +more positive more it is the group + + align:start position:0% +more positive more it is the group + + + align:start position:0% +more positive more it is the group +dynamic and and getting okay more you + + align:start position:0% +dynamic and and getting okay more you + + + align:start position:0% +dynamic and and getting okay more you +know when you look around the room you + + align:start position:0% +know when you look around the room you + + + align:start position:0% +know when you look around the room you +feel like I kind of know some of these + + align:start position:0% +feel like I kind of know some of these + + + align:start position:0% +feel like I kind of know some of these +okay you're right that it's not stated + + align:start position:0% +okay you're right that it's not stated + + + align:start position:0% +okay you're right that it's not stated +but that wasn't the question we were + + align:start position:0% +but that wasn't the question we were + + + align:start position:0% +but that wasn't the question we were +asked to express we were asked to + + align:start position:0% +asked to express we were asked to + + + align:start position:0% +asked to express we were asked to +express the critical moment not why it + + align:start position:0% +express the critical moment not why it + + + align:start position:0% +express the critical moment not why it +was a critical moment okay I think you + + align:start position:0% +was a critical moment okay I think you + + + align:start position:0% +was a critical moment okay I think you +express behind what yes it's behind the + + align:start position:0% +express behind what yes it's behind the + + + align:start position:0% +express behind what yes it's behind the +these critical moments we have the + + align:start position:0% +these critical moments we have the + + + align:start position:0% +these critical moments we have the +process of + + align:start position:0% +process of + + + align:start position:0% +process of +group dynamic dynamic okay well just + + align:start position:0% +group dynamic dynamic okay well just + + + align:start position:0% +group dynamic dynamic okay well just +like your your + + align:start position:0% +like your your + + + align:start position:0% +like your your +assumption that um that the first + + align:start position:0% +assumption that um that the first + + + align:start position:0% +assumption that um that the first +experience was the first time we let + + align:start position:0% +experience was the first time we let + + + align:start position:0% +experience was the first time we let +ourselves be uh vulnerable and and then + + align:start position:0% +ourselves be uh vulnerable and and then + + + align:start position:0% +ourselves be uh vulnerable and and then +it was it was better that's your + + align:start position:0% +it was it was better that's your + + + align:start position:0% +it was it was better that's your +assumption about why these were critical + + align:start position:0% +assumption about why these were critical + + + align:start position:0% +assumption about why these were critical +moments exactly it's not there it's not + + align:start position:0% +moments exactly it's not there it's not + + + align:start position:0% +moments exactly it's not there it's not +there we are assuming you are assuming I + + align:start position:0% +there we are assuming you are assuming I + + + align:start position:0% +there we are assuming you are assuming I +know + + align:start position:0% +know + + + align:start position:0% +know +you I haven't considered it if you want + + align:start position:0% +you I haven't considered it if you want + + + align:start position:0% +you I haven't considered it if you want +me to I can come up with with an + + align:start position:0% +me to I can come up with with an + + + align:start position:0% +me to I can come up with with an +assumption as + + align:start position:0% +assumption as + + + align:start position:0% +assumption as +well so good I I try to to read to + + align:start position:0% +well so good I I try to to read to + + + align:start position:0% +well so good I I try to to read to +interpret what people are telling me I + + align:start position:0% +interpret what people are telling me I + + + align:start position:0% +interpret what people are telling me I +have no opinion about this yet yes you + + align:start position:0% +have no opinion about this yet yes you + + + align:start position:0% +have no opinion about this yet yes you +created an opinion maybe but she she + + align:start position:0% +created an opinion maybe but she she + + + align:start position:0% +created an opinion maybe but she she +expressed that there was a group dynamic + + align:start position:0% +expressed that there was a group dynamic + + + align:start position:0% +expressed that there was a group dynamic +and jod also express it and Claudia also + + align:start position:0% +and jod also express it and Claudia also + + + align:start position:0% +and jod also express it and Claudia also +expressed the same feeling so + + align:start position:0% +expressed the same feeling so + + + align:start position:0% +expressed the same feeling so +I to it for me I have not opinion about + + align:start position:0% +I to it for me I have not opinion about + + + align:start position:0% +I to it for me I have not opinion about +this yet yeah okay + + align:start position:0% + + + + align:start position:0% + +Le yes she she has a question okay okay + + align:start position:0% +Le yes she she has a question okay okay + + + align:start position:0% +Le yes she she has a question okay okay +oh I was about to ask I here on the + + align:start position:0% +oh I was about to ask I here on the + + + align:start position:0% +oh I was about to ask I here on the +first 4 days is that the first day of + + align:start position:0% +first 4 days is that the first day of + + + align:start position:0% +first 4 days is that the first day of +exercise of + + align:start position:0% +exercise of + + + align:start position:0% +exercise of +exercises when was the first the first + + align:start position:0% +exercises when was the first the first + + + align:start position:0% +exercises when was the first the first +day was about learning and that was + + align:start position:0% +day was about learning and that was + + + align:start position:0% +day was about learning and that was +there was a group exercise there was a + + align:start position:0% +there was a group exercise there was a + + + align:start position:0% +there was a group exercise there was a +for every + + align:start position:0% +for every + + + align:start position:0% +for every +day yes yes all the days there were a + + align:start position:0% +day yes yes all the days there were a + + + align:start position:0% +day yes yes all the days there were a +group + + align:start position:0% +group + + + align:start position:0% +group +exercises + + align:start position:0% +exercises + + + align:start position:0% +exercises +okay I just going to say that and I'm + + align:start position:0% +okay I just going to say that and I'm + + + align:start position:0% +okay I just going to say that and I'm +I'm speaking strictly on my own behalf + + align:start position:0% +I'm speaking strictly on my own behalf + + + align:start position:0% +I'm speaking strictly on my own behalf +um for me emotional feel I think the the + + align:start position:0% +um for me emotional feel I think the the + + + align:start position:0% +um for me emotional feel I think the the +negative um leading up to Friday + + align:start position:0% +negative um leading up to Friday + + + align:start position:0% +negative um leading up to Friday +Thursday the fourth um I agree that we + + align:start position:0% +Thursday the fourth um I agree that we + + + align:start position:0% +Thursday the fourth um I agree that we +were kind of getting Concepts and + + align:start position:0% +were kind of getting Concepts and + + + align:start position:0% +were kind of getting Concepts and +understanding feeling you know trying to + + align:start position:0% +understanding feeling you know trying to + + + align:start position:0% +understanding feeling you know trying to +see where the work was going but for me + + align:start position:0% +see where the work was going but for me + + + align:start position:0% +see where the work was going but for me +on Thursday the exercise that was + + align:start position:0% +on Thursday the exercise that was + + + align:start position:0% +on Thursday the exercise that was +chosen really um it bubbled up a lot of + + align:start position:0% +chosen really um it bubbled up a lot of + + + align:start position:0% +chosen really um it bubbled up a lot of +emotions that come out certainly for me + + align:start position:0% +emotions that come out certainly for me + + + align:start position:0% +emotions that come out certainly for me +when you talk about issues of race and I + + align:start position:0% +when you talk about issues of race and I + + + align:start position:0% +when you talk about issues of race and I +think that that exercise that was + + align:start position:0% +think that that exercise that was + + + align:start position:0% +think that that exercise that was +chosen um made me go back and really + + align:start position:0% +chosen um made me go back and really + + + align:start position:0% +chosen um made me go back and really +look + + align:start position:0% +look + + + align:start position:0% +look +at how important how when you're trying + + align:start position:0% +at how important how when you're trying + + + align:start position:0% +at how important how when you're trying +to sort of articulate or um and not that + + align:start position:0% +to sort of articulate or um and not that + + + align:start position:0% +to sort of articulate or um and not that +you even have to own it but when you're + + align:start position:0% +you even have to own it but when you're + + + align:start position:0% +you even have to own it but when you're +trying to + + align:start position:0% +trying to + + + align:start position:0% +trying to +articulate um Concepts or get + + align:start position:0% + + + + align:start position:0% + +um theories across how difficult it is + + align:start position:0% +um theories across how difficult it is + + + align:start position:0% +um theories across how difficult it is +to use issues around race to convey that + + align:start position:0% +to use issues around race to convey that + + + align:start position:0% +to use issues around race to convey that +concept if you know what I mean and I + + align:start position:0% +concept if you know what I mean and I + + + align:start position:0% +concept if you know what I mean and I +think it it just it it really Disturbed + + align:start position:0% +think it it just it it really Disturbed + + + align:start position:0% +think it it just it it really Disturbed +me in a way that I had to really + + align:start position:0% +me in a way that I had to really + + + align:start position:0% +me in a way that I had to really +reconsider why am I here and so that's + + align:start position:0% +reconsider why am I here and so that's + + + align:start position:0% +reconsider why am I here and so that's +why I put negative and positive because + + align:start position:0% +why I put negative and positive because + + + align:start position:0% +why I put negative and positive because +I think that the whole notion of the + + align:start position:0% +I think that the whole notion of the + + + align:start position:0% +I think that the whole notion of the +concept you know the that we were + + align:start position:0% +concept you know the that we were + + + align:start position:0% +concept you know the that we were +talking about on that day + + align:start position:0% +talking about on that day + + + align:start position:0% +talking about on that day +was trying to understand framing or + + align:start position:0% +was trying to understand framing or + + + align:start position:0% +was trying to understand framing or +reframing theor and use theories and use + + align:start position:0% +reframing theor and use theories and use + + + align:start position:0% +reframing theor and use theories and use +and but because we're dealing with an + + align:start position:0% +and but because we're dealing with an + + + align:start position:0% +and but because we're dealing with an +issue that's so complex in this + + align:start position:0% +issue that's so complex in this + + + align:start position:0% +issue that's so complex in this +society and so emotional it just + + align:start position:0% +society and so emotional it just + + + align:start position:0% +society and so emotional it just +barricaded my ability to really get it + + align:start position:0% +barricaded my ability to really get it + + + align:start position:0% +barricaded my ability to really get it +and I had to go home and really think + + align:start position:0% +and I had to go home and really think + + + align:start position:0% +and I had to go home and really think +about it and really sort of understand + + align:start position:0% +about it and really sort of understand + + + align:start position:0% +about it and really sort of understand +that I had to separate the issue so I + + align:start position:0% +that I had to separate the issue so I + + + align:start position:0% +that I had to separate the issue so I +think it's by it certainly opened up + + align:start position:0% +think it's by it certainly opened up + + + align:start position:0% +think it's by it certainly opened up +my my mind and my openness to receiving + + align:start position:0% +my my mind and my openness to receiving + + + align:start position:0% +my my mind and my openness to receiving +the information and understanding what + + align:start position:0% +the information and understanding what + + + align:start position:0% +the information and understanding what +it was you're here to do what I'm here + + align:start position:0% +it was you're here to do what I'm here + + + align:start position:0% +it was you're here to do what I'm here +to do why I'm here + + align:start position:0% +to do why I'm here + + + align:start position:0% +to do why I'm here +so thank you please isn't that is that I + + align:start position:0% +so thank you please isn't that is that I + + + align:start position:0% +so thank you please isn't that is that I +kind of feel like is not a great + + align:start position:0% +kind of feel like is not a great + + + align:start position:0% +kind of feel like is not a great +exercise though to have I mean it's hard + + align:start position:0% +exercise though to have I mean it's hard + + + align:start position:0% +exercise though to have I mean it's hard +it's much harder to do it with race but + + align:start position:0% +it's much harder to do it with race but + + + align:start position:0% +it's much harder to do it with race but +to have that charge cuz I mean you know + + align:start position:0% +to have that charge cuz I mean you know + + + align:start position:0% +to have that charge cuz I mean you know +these are the situations that happen in + + align:start position:0% +these are the situations that happen in + + + align:start position:0% +these are the situations that happen in +the real world people get really charged + + align:start position:0% +the real world people get really charged + + + align:start position:0% +the real world people get really charged +about issues and you can't you can't + + align:start position:0% +about issues and you can't you can't + + + align:start position:0% +about issues and you can't you can't +just separate your emotions you know on + + align:start position:0% +just separate your emotions you know on + + + align:start position:0% +just separate your emotions you know on +something like race or I don't class + + align:start position:0% +something like race or I don't class + + + align:start position:0% +something like race or I don't class +issues or postwar I mean whatever the + + align:start position:0% +issues or postwar I mean whatever the + + + align:start position:0% +issues or postwar I mean whatever the +issue is you know I mean are you saying + + align:start position:0% +issue is you know I mean are you saying + + + align:start position:0% +issue is you know I mean are you saying +do you think it was good to have it so + + align:start position:0% +do you think it was good to have it so + + + align:start position:0% +do you think it was good to have it so +early you think it would have been + + align:start position:0% +early you think it would have been + + + align:start position:0% +early you think it would have been +better to have it later on or not at all + + align:start position:0% +better to have it later on or not at all + + + align:start position:0% +better to have it later on or not at all +I think it would be better not to have + + align:start position:0% +I think it would be better not to have + + + align:start position:0% +I think it would be better not to have +it at + + align:start position:0% +it at + + + align:start position:0% +it at +all for me I mean because the impact + + align:start position:0% +all for me I mean because the impact + + + align:start position:0% +all for me I mean because the impact +that it had on me was just not a + + align:start position:0% +that it had on me was just not a + + + align:start position:0% +that it had on me was just not a +positive impact and it it almost + + align:start position:0% +positive impact and it it almost + + + align:start position:0% +positive impact and it it almost +Disturbed me to the point where I didn't + + align:start position:0% +Disturbed me to the point where I didn't + + + align:start position:0% +Disturbed me to the point where I didn't +even want to + + align:start position:0% +even want to + + + align:start position:0% +even want to +come back and that was so ridiculous go + + align:start position:0% +come back and that was so ridiculous go + + + align:start position:0% +come back and that was so ridiculous go +back and really think about what that + + align:start position:0% +back and really think about what that + + + align:start position:0% +back and really think about what that +meant for me and I actually had a + + align:start position:0% +meant for me and I actually had a + + + align:start position:0% +meant for me and I actually had a +conversation with Caesar about it + + align:start position:0% +conversation with Caesar about it + + + align:start position:0% +conversation with Caesar about it +because I was just really so disturbed + + align:start position:0% +because I was just really so disturbed + + + align:start position:0% +because I was just really so disturbed +by the whole thing and it wasn't it + + align:start position:0% +by the whole thing and it wasn't it + + + align:start position:0% +by the whole thing and it wasn't it +wasn't anything anyone said it was just + + align:start position:0% +wasn't anything anyone said it was just + + + align:start position:0% +wasn't anything anyone said it was just +the circumstances of the world that + + align:start position:0% +the circumstances of the world that + + + align:start position:0% +the circumstances of the world that +we're living in and working in and + + align:start position:0% +we're living in and working in and + + + align:start position:0% +we're living in and working in and +trying to fight for justice um so it + + align:start position:0% +trying to fight for justice um so it + + + align:start position:0% +trying to fight for justice um so it +wasn't the class it was + + align:start position:0% +wasn't the class it was + + + align:start position:0% +wasn't the class it was +just you know I guess I was society and + + align:start position:0% +just you know I guess I was society and + + + align:start position:0% +just you know I guess I was society and +I it just really Disturbed my spirit so + + align:start position:0% +I it just really Disturbed my spirit so + + + align:start position:0% +I it just really Disturbed my spirit so +what made you tell us about this + + align:start position:0% +what made you tell us about this + + + align:start position:0% +what made you tell us about this +critical moment + + align:start position:0% + + + + align:start position:0% + +here what made you tell what what made + + align:start position:0% +here what made you tell what what made + + + align:start position:0% +here what made you tell what what made +me tell so you're telling us you know + + align:start position:0% +me tell so you're telling us you know + + + align:start position:0% +me tell so you're telling us you know +you're telling us about this like you + + align:start position:0% +you're telling us about this like you + + + align:start position:0% +you're telling us about this like you +being very disturbed that day but then + + align:start position:0% +being very disturbed that day but then + + + align:start position:0% +being very disturbed that day but then +something I think your conversation with + + align:start position:0% +something I think your conversation with + + + align:start position:0% +something I think your conversation with +Caesar all tell us about what happened + + align:start position:0% +Caesar all tell us about what happened + + + align:start position:0% +Caesar all tell us about what happened +here no it was a conversation with + + align:start position:0% +here no it was a conversation with + + + align:start position:0% +here no it was a conversation with +myself when I went home that night and + + align:start position:0% +myself when I went home that night and + + + align:start position:0% +myself when I went home that night and +then Contin with Caesar the following + + align:start position:0% +then Contin with Caesar the following + + + align:start position:0% +then Contin with Caesar the following +day really made + + align:start position:0% +day really made + + + align:start position:0% +day really made +me + + align:start position:0% +me + + + align:start position:0% +me +separate the purpose of while we're here + + align:start position:0% +separate the purpose of while we're here + + + align:start position:0% +separate the purpose of while we're here +and what value can come out of a process + + align:start position:0% +and what value can come out of a process + + + align:start position:0% +and what value can come out of a process +like this and giv some hope for working + + align:start position:0% +like this and giv some hope for working + + + align:start position:0% +like this and giv some hope for working +through hard issues that communities + + align:start position:0% +through hard issues that communities + + + align:start position:0% +through hard issues that communities +face with every day um I thought that + + align:start position:0% +face with every day um I thought that + + + align:start position:0% +face with every day um I thought that +this this process could maybe help + + align:start position:0% +this this process could maybe help + + + align:start position:0% +this this process could maybe help +others understand some of the + + align:start position:0% +others understand some of the + + + align:start position:0% +others understand some of the +complicated issues that we're deing with + + align:start position:0% +complicated issues that we're deing with + + + align:start position:0% +complicated issues that we're deing with +every day so I had to really dig deep + + align:start position:0% +every day so I had to really dig deep + + + align:start position:0% +every day so I had to really dig deep +and + + align:start position:0% +and + + + align:start position:0% +and +separate my emotions + + align:start position:0% +separate my emotions + + + align:start position:0% +separate my emotions +from the issue and the purpose and look + + align:start position:0% +from the issue and the purpose and look + + + align:start position:0% +from the issue and the purpose and look +at this this series of this class as an + + align:start position:0% +at this this series of this class as an + + + align:start position:0% +at this this series of this class as an +opportunity to perhaps use in my work to + + align:start position:0% +opportunity to perhaps use in my work to + + + align:start position:0% +opportunity to perhaps use in my work to +have others who are struggl the same + + align:start position:0% +have others who are struggl the same + + + align:start position:0% +have others who are struggl the same +issues race and class and all those + + align:start position:0% +issues race and class and all those + + + align:start position:0% +issues race and class and all those +things that the is that + + align:start position:0% +things that the is that + + + align:start position:0% +things that the is that +we okay thank you + + align:start position:0% +we okay thank you + + + align:start position:0% +we okay thank you +please oh no any other comment about + + align:start position:0% + + + + align:start position:0% + +this okay I just said one thing I was oh + + align:start position:0% +this okay I just said one thing I was oh + + + align:start position:0% +this okay I just said one thing I was oh +yes I thought when we did the Framingham + + align:start position:0% +yes I thought when we did the Framingham + + + align:start position:0% +yes I thought when we did the Framingham +when we heard c talk about the + + align:start position:0% +when we heard c talk about the + + + align:start position:0% +when we heard c talk about the +Framingham k no situation and then we + + align:start position:0% +Framingham k no situation and then we + + + align:start position:0% +Framingham k no situation and then we +did the problem solving together that + + align:start position:0% +did the problem solving together that + + + align:start position:0% +did the problem solving together that +was a very rich experience for me you + + align:start position:0% +was a very rich experience for me you + + + align:start position:0% +was a very rich experience for me you +know where we all contributed what we + + align:start position:0% +know where we all contributed what we + + + align:start position:0% +know where we all contributed what we +knew or heard or experienced our own + + align:start position:0% +knew or heard or experienced our own + + + align:start position:0% +knew or heard or experienced our own +practice I thought that was an excellent + + align:start position:0% +practice I thought that was an excellent + + + align:start position:0% +practice I thought that was an excellent +day particularly for + + align:start position:0% +day particularly for + + + align:start position:0% +day particularly for +me okay so um yes so the question um one + + align:start position:0% +me okay so um yes so the question um one + + + align:start position:0% +me okay so um yes so the question um one +of the questions that you guys picked + + align:start position:0% +of the questions that you guys picked + + + align:start position:0% +of the questions that you guys picked +today was how to make reflective + + align:start position:0% +today was how to make reflective + + + align:start position:0% +today was how to make reflective +practice common practice like more + + align:start position:0% +practice common practice like more + + + align:start position:0% +practice common practice like more +practical and natur + + align:start position:0% +practical and natur + + + align:start position:0% +practical and natur +for our for + + align:start position:0% +for our for + + + align:start position:0% +for our for +us if we were to do this whole + + align:start position:0% +us if we were to do this whole + + + align:start position:0% +us if we were to do this whole +methodology and finish we what we would + + align:start position:0% +methodology and finish we what we would + + + align:start position:0% +methodology and finish we what we would +do at this point is see which of these + + align:start position:0% +do at this point is see which of these + + + align:start position:0% +do at this point is see which of these +critical moments if we if we understood + + align:start position:0% +critical moments if we if we understood + + + align:start position:0% +critical moments if we if we understood +better if we could + + align:start position:0% +better if we could + + + align:start position:0% +better if we could +analyze in more depth we would begin to + + align:start position:0% +analyze in more depth we would begin to + + + align:start position:0% +analyze in more depth we would begin to +answer this + + align:start position:0% +answer this + + + align:start position:0% +answer this +question + + align:start position:0% + + + + align:start position:0% + +okay no + + align:start position:0% + + + + align:start position:0% + +looking at + + align:start position:0% +looking at + + + align:start position:0% +looking at +the yes looking at + + align:start position:0% + + + + align:start position:0% + +the no I'm describing the methodology as + + align:start position:0% +the no I'm describing the methodology as + + + align:start position:0% +the no I'm describing the methodology as +as it's not what we're going to do now + + align:start position:0% +as it's not what we're going to do now + + + align:start position:0% +as it's not what we're going to do now +as so I think it's important for you to + + align:start position:0% +as so I think it's important for you to + + + align:start position:0% +as so I think it's important for you to +know what it is so that you know that + + align:start position:0% +know what it is so that you know that + + + align:start position:0% +know what it is so that you know that +we're making a change okay so how it + + align:start position:0% +we're making a change okay so how it + + + align:start position:0% +we're making a change okay so how it +usually works is you look at all these + + align:start position:0% +usually works is you look at all these + + + align:start position:0% +usually works is you look at all these +critical moments and you begin to + + align:start position:0% +critical moments and you begin to + + + align:start position:0% +critical moments and you begin to +identify the ones that if you analyze in + + align:start position:0% +identify the ones that if you analyze in + + + align:start position:0% +identify the ones that if you analyze in +depth through storytelling you would be + + align:start position:0% +depth through storytelling you would be + + + align:start position:0% +depth through storytelling you would be +able to begin to answer this ingry + + align:start position:0% +able to begin to answer this ingry + + + align:start position:0% +able to begin to answer this ingry +question okay we're not going to do that + + align:start position:0% +question okay we're not going to do that + + + align:start position:0% +question okay we're not going to do that +what we're going to do is just in + + align:start position:0% +what we're going to do is just in + + + align:start position:0% +what we're going to do is just in +general if you look at the distribution + + align:start position:0% +general if you look at the distribution + + + align:start position:0% +general if you look at the distribution +of these critical moments and what we + + align:start position:0% +of these critical moments and what we + + + align:start position:0% +of these critical moments and what we +just discussed is there anything that + + align:start position:0% +just discussed is there anything that + + + align:start position:0% +just discussed is there anything that +comes to your mind that could help you + + align:start position:0% +comes to your mind that could help you + + + align:start position:0% +comes to your mind that could help you +begin to answer this question what ideas + + align:start position:0% +begin to answer this question what ideas + + + align:start position:0% +begin to answer this question what ideas +do + + align:start position:0% + + + + align:start position:0% + +you okay + + align:start position:0% + + + + align:start position:0% + +one question we have two questions no + + align:start position:0% +one question we have two questions no + + + align:start position:0% +one question we have two questions no +we're just going to focus because of + + align:start position:0% +we're just going to focus because of + + + align:start position:0% +we're just going to focus because of +time we're just going to focus on this + + align:start position:0% + + + + align:start position:0% + +question okay CL + + align:start position:0% +question okay CL + + + align:start position:0% +question okay CL +suggesting we're we're going to focus on + + align:start position:0% +suggesting we're we're going to focus on + + + align:start position:0% +suggesting we're we're going to focus on +this question of all the question + + align:start position:0% +this question of all the question + + + align:start position:0% +this question of all the question +questions okay if that's okay with you + + align:start position:0% +questions okay if that's okay with you + + + align:start position:0% +questions okay if that's okay with you +guys because of + + align:start position:0% + + + + align:start position:0% + +time okay how to + + align:start position:0% +time okay how to + + + align:start position:0% +time okay how to +make reflective practice common + + align:start position:0% +make reflective practice common + + + align:start position:0% +make reflective practice common +practice + + align:start position:0% +practice + + + align:start position:0% +practice +okay thinking about + + align:start position:0% + + + + align:start position:0% + +this thinking about your own experience + + align:start position:0% +this thinking about your own experience + + + align:start position:0% +this thinking about your own experience +and the experience that you saw from the + + align:start position:0% +and the experience that you saw from the + + + align:start position:0% +and the experience that you saw from the +other people + + align:start position:0% +other people + + + align:start position:0% +other people +these days you are try to learn + + align:start position:0% +these days you are try to learn + + + align:start position:0% +these days you are try to learn +reflective practice you are trying to + + align:start position:0% +reflective practice you are trying to + + + align:start position:0% +reflective practice you are trying to +apply reflective practice and now + + align:start position:0% +apply reflective practice and now + + + align:start position:0% +apply reflective practice and now +from this reconstruction we have made + + align:start position:0% +from this reconstruction we have made + + + align:start position:0% +from this reconstruction we have made +what you can find that should be useful + + align:start position:0% +what you can find that should be useful + + + align:start position:0% +what you can find that should be useful +for having ideas about how to make a + + align:start position:0% +for having ideas about how to make a + + + align:start position:0% +for having ideas about how to make a +common + + align:start position:0% +common + + + align:start position:0% +common +practice how to make ref reflective + + align:start position:0% +practice how to make ref reflective + + + align:start position:0% +practice how to make ref reflective +practice a common practice like more + + align:start position:0% +practice a common practice like more + + + align:start position:0% +practice a common practice like more +practical and natural yes there have + + align:start position:0% +practical and natural yes there have + + + align:start position:0% +practical and natural yes there have +been a lot of theories thrown out about + + align:start position:0% +been a lot of theories thrown out about + + + align:start position:0% +been a lot of theories thrown out about +why these clustered in a way that they + + align:start position:0% +why these clustered in a way that they + + + align:start position:0% +why these clustered in a way that they +did if we take the assumption that it's + + align:start position:0% +did if we take the assumption that it's + + + align:start position:0% +did if we take the assumption that it's +because uh your your analysis which I + + align:start position:0% +because uh your your analysis which I + + + align:start position:0% +because uh your your analysis which I +like about it was hard at the beginning + + align:start position:0% +like about it was hard at the beginning + + + align:start position:0% +like about it was hard at the beginning +for people to really analyze their + + align:start position:0% +for people to really analyze their + + + align:start position:0% +for people to really analyze their +assumptions and then as they gotten more + + align:start position:0% +assumptions and then as they gotten more + + + align:start position:0% +assumptions and then as they gotten more +and more practice they started to be + + align:start position:0% +and more practice they started to be + + + align:start position:0% +and more practice they started to be +more and more comfortable with being in + + align:start position:0% +more and more comfortable with being in + + + align:start position:0% +more and more comfortable with being in +that limbo land that you talking about + + align:start position:0% +that limbo land that you talking about + + + align:start position:0% +that limbo land that you talking about +not quite knowing where they stood in + + align:start position:0% +not quite knowing where they stood in + + + align:start position:0% +not quite knowing where they stood in +terms of their + + align:start position:0% +terms of their + + + align:start position:0% +terms of their +assumptions that when we're dealing with + + align:start position:0% +assumptions that when we're dealing with + + + align:start position:0% +assumptions that when we're dealing with +people out in the real world who haven't + + align:start position:0% +people out in the real world who haven't + + + align:start position:0% +people out in the real world who haven't +taken this 10day course we're going to + + align:start position:0% +taken this 10day course we're going to + + + align:start position:0% +taken this 10day course we're going to +get people who are not even at day four + + align:start position:0% +get people who are not even at day four + + + align:start position:0% +get people who are not even at day four +they're they're at day one okay and so + + align:start position:0% +they're they're at day one okay and so + + + align:start position:0% +they're they're at day one okay and so +not even if they're day zero even seen + + align:start position:0% +not even if they're day zero even seen + + + align:start position:0% +not even if they're day zero even seen +the post + + align:start position:0% + + + + align:start position:0% + +so the closest thing out of all of those + + align:start position:0% +so the closest thing out of all of those + + + align:start position:0% +so the closest thing out of all of those +days the closest thing that gets to day + + align:start position:0% +days the closest thing that gets to day + + + align:start position:0% +days the closest thing that gets to day +Zero is all these problems people had at + + align:start position:0% +Zero is all these problems people had at + + + align:start position:0% +Zero is all these problems people had at +day four and so I feel like if we + + align:start position:0% +day four and so I feel like if we + + + align:start position:0% +day four and so I feel like if we +analyzed what's going on with all those + + align:start position:0% +analyzed what's going on with all those + + + align:start position:0% +analyzed what's going on with all those +problems in day four we'd have a better + + align:start position:0% +problems in day four we'd have a better + + + align:start position:0% +problems in day four we'd have a better +sense of what problems we might + + align:start position:0% +sense of what problems we might + + + align:start position:0% +sense of what problems we might +encounter with others when we try and + + align:start position:0% +encounter with others when we try and + + + align:start position:0% +encounter with others when we try and +integrate this into our work and that + + align:start position:0% +integrate this into our work and that + + + align:start position:0% +integrate this into our work and that +might help us answer the question of how + + align:start position:0% +might help us answer the question of how + + + align:start position:0% +might help us answer the question of how +do we do it on a daily basis at least in + + align:start position:0% +do we do it on a daily basis at least in + + + align:start position:0% +do we do it on a daily basis at least in +terms but could you synthesize your idea + + align:start position:0% +terms but could you synthesize your idea + + + align:start position:0% +terms but could you synthesize your idea +in just one phrase one yes the idea that + + align:start position:0% +in just one phrase one yes the idea that + + + align:start position:0% +in just one phrase one yes the idea that +you think that make may help + + align:start position:0% + + + + align:start position:0% + +to + + align:start position:0% + + + + align:start position:0% + +why it gets a little bit back to Chris's + + align:start position:0% +why it gets a little bit back to Chris's + + + align:start position:0% +why it gets a little bit back to Chris's +question why people struggled with that + + align:start position:0% +question why people struggled with that + + + align:start position:0% +question why people struggled with that +exercise okay and if we could understand + + align:start position:0% +exercise okay and if we could understand + + + align:start position:0% +exercise okay and if we could understand +why then it struggled with that exercise + + align:start position:0% +why then it struggled with that exercise + + + align:start position:0% +why then it struggled with that exercise +we might be able to understand how we + + align:start position:0% +we might be able to understand how we + + + align:start position:0% +we might be able to understand how we +could okay practice in use this in our + + align:start position:0% +could okay practice in use this in our + + + align:start position:0% +could okay practice in use this in our +daily practice and it would also help + + align:start position:0% +daily practice and it would also help + + + align:start position:0% +daily practice and it would also help +address the question that I had about + + align:start position:0% +address the question that I had about + + + align:start position:0% +address the question that I had about +how do you bring this into a larger + + align:start position:0% +how do you bring this into a larger + + + align:start position:0% +how do you bring this into a larger +scale of working with other people and + + align:start position:0% +scale of working with other people and + + + align:start position:0% +scale of working with other people and +getting them to think in the same terms + + align:start position:0% +getting them to think in the same terms + + + align:start position:0% +getting them to think in the same terms +which I think + + align:start position:0% +which I think + + + align:start position:0% +which I think +also okay I think I think Chris's + + align:start position:0% +also okay I think I think Chris's + + + align:start position:0% +also okay I think I think Chris's +question how what what can we learn from + + align:start position:0% +question how what what can we learn from + + + align:start position:0% +question how what what can we learn from +analyzing the problems people had with + + align:start position:0% + + + + align:start position:0% + +exercise anyone have ideas about this + + align:start position:0% +exercise anyone have ideas about this + + + align:start position:0% +exercise anyone have ideas about this +question yes I I'm not sure if that even + + align:start position:0% +question yes I I'm not sure if that even + + + align:start position:0% +question yes I I'm not sure if that even +makes sense but I think based on what + + align:start position:0% +makes sense but I think based on what + + + align:start position:0% +makes sense but I think based on what +Lee had say and the impact of this + + align:start position:0% +Lee had say and the impact of this + + + align:start position:0% +Lee had say and the impact of this +exercise has caused on her and Bas off + + align:start position:0% +exercise has caused on her and Bas off + + + align:start position:0% +exercise has caused on her and Bas off +some of the experience I have and what + + align:start position:0% +some of the experience I have and what + + + align:start position:0% +some of the experience I have and what +you saying Ben sentence at the beginning + + align:start position:0% +you saying Ben sentence at the beginning + + + align:start position:0% +you saying Ben sentence at the beginning +it's so critical if you have to go in a + + align:start position:0% +it's so critical if you have to go in a + + + align:start position:0% +it's so critical if you have to go in a +community and you only have half an hour + + align:start position:0% +community and you only have half an hour + + + align:start position:0% +community and you only have half an hour +an hour to to bring an idea to bring a + + align:start position:0% +an hour to to bring an idea to bring a + + + align:start position:0% +an hour to to bring an idea to bring a +uh something that's going to touch many + + align:start position:0% +uh something that's going to touch many + + + align:start position:0% +uh something that's going to touch many +sensitive people there who might be the + + align:start position:0% +sensitive people there who might be the + + + align:start position:0% +sensitive people there who might be the +ones who make things happen how can you + + align:start position:0% +ones who make things happen how can you + + + align:start position:0% +ones who make things happen how can you +deal with that and I find that basic on + + align:start position:0% +deal with that and I find that basic on + + + align:start position:0% +deal with that and I find that basic on +what we see here is to be able to + + align:start position:0% +what we see here is to be able to + + + align:start position:0% +what we see here is to be able to +describe this kind of practice in a very + + align:start position:0% +describe this kind of practice in a very + + + align:start position:0% +describe this kind of practice in a very +small way when you come to a place when + + align:start position:0% +small way when you come to a place when + + + align:start position:0% +small way when you come to a place when +you're trying to identify is be able to + + align:start position:0% +you're trying to identify is be able to + + + align:start position:0% +you're trying to identify is be able to +be to have a dialogue and I think we go + + align:start position:0% +be to have a dialogue and I think we go + + + align:start position:0% +be to have a dialogue and I think we go +back to the dialogue of of bring this + + align:start position:0% +back to the dialogue of of bring this + + + align:start position:0% +back to the dialogue of of bring this +kind of understanding to whatever way + + align:start position:0% +kind of understanding to whatever way + + + align:start position:0% +kind of understanding to whatever way +you're going to work so you won't have + + align:start position:0% +you're going to work so you won't have + + + align:start position:0% +you're going to work so you won't have +reaction like that when people walk away + + align:start position:0% +reaction like that when people walk away + + + align:start position:0% +reaction like that when people walk away +because what you're trying where you're + + align:start position:0% +because what you're trying where you're + + + align:start position:0% +because what you're trying where you're +trying to get does that make sense okay + + align:start position:0% +trying to get does that make sense okay + + + align:start position:0% +trying to get does that make sense okay +thank you + + align:start position:0% +thank you + + + align:start position:0% +thank you +CIA she asked it first I + + align:start position:0% +CIA she asked it first I + + + align:start position:0% +CIA she asked it first I +said common practice implicates a + + align:start position:0% +said common practice implicates a + + + align:start position:0% +said common practice implicates a +certain maturity of group dynamics to + + align:start position:0% +certain maturity of group dynamics to + + + align:start position:0% +certain maturity of group dynamics to +happen Okay in terms of individual + + align:start position:0% +happen Okay in terms of individual + + + align:start position:0% +happen Okay in terms of individual +dynamic or individual dynamic in the + + align:start position:0% +dynamic or individual dynamic in the + + + align:start position:0% +dynamic or individual dynamic in the +relationship with the people that you + + align:start position:0% +relationship with the people that you + + + align:start position:0% +relationship with the people that you +are working with are the people that are + + align:start position:0% +are working with are the people that are + + + align:start position:0% +are working with are the people that are +part of the community that you intend to + + align:start position:0% +part of the community that you intend to + + + align:start position:0% +part of the community that you intend to +where you intend to + + align:start position:0% +where you intend to + + + align:start position:0% +where you intend to +implement the reflective practice or a + + align:start position:0% +implement the reflective practice or a + + + align:start position:0% +implement the reflective practice or a +culture of reflective practice it's not + + align:start position:0% +culture of reflective practice it's not + + + align:start position:0% +culture of reflective practice it's not +what I mean is it's just not something + + align:start position:0% +what I mean is it's just not something + + + align:start position:0% +what I mean is it's just not something +that happens in the first day it + + align:start position:0% +that happens in the first day it + + + align:start position:0% +that happens in the first day it +replicates certain process + + align:start position:0% +replicates certain process + + + align:start position:0% +replicates certain process +of familiarization with the groups the + + align:start position:0% +of familiarization with the groups the + + + align:start position:0% +of familiarization with the groups the +group of + + align:start position:0% +group of + + + align:start position:0% +group of +okay people need to feel comfortable + + align:start position:0% +okay people need to feel comfortable + + + align:start position:0% +okay people need to feel comfortable +with the others they need to trust each + + align:start position:0% +with the others they need to trust each + + + align:start position:0% +with the others they need to trust each +others things like that they need to + + align:start position:0% +others things like that they need to + + + align:start position:0% +others things like that they need to +construct some kind of relation among + + align:start position:0% +construct some kind of relation among + + + align:start position:0% +construct some kind of relation among +them for feel comfortable sharing this + + align:start position:0% +them for feel comfortable sharing this + + + align:start position:0% +them for feel comfortable sharing this +kind of + + align:start position:0% +kind of + + + align:start position:0% +kind of +effort okay Chris I I would almost + + align:start position:0% +effort okay Chris I I would almost + + + align:start position:0% +effort okay Chris I I would almost +phrase what you're saying like I agree + + align:start position:0% +phrase what you're saying like I agree + + + align:start position:0% +phrase what you're saying like I agree +with what you're saying I almost phrase + + align:start position:0% +with what you're saying I almost phrase + + + align:start position:0% +with what you're saying I almost phrase +it as Unity like you know it's like + + align:start position:0% +it as Unity like you know it's like + + + align:start position:0% +it as Unity like you know it's like +there's sort of a sense of shared Spirit + + align:start position:0% +there's sort of a sense of shared Spirit + + + align:start position:0% +there's sort of a sense of shared Spirit +or common like there's a common energy + + align:start position:0% +or common like there's a common energy + + + align:start position:0% +or common like there's a common energy +that sort of develops over time that you + + align:start position:0% +that sort of develops over time that you + + + align:start position:0% +that sort of develops over time that you +don't get in the first day and or two + + align:start position:0% +don't get in the first day and or two + + + align:start position:0% +don't get in the first day and or two +days the first two or 3 days which maybe + + align:start position:0% +days the first two or 3 days which maybe + + + align:start position:0% +days the first two or 3 days which maybe +you know I mean once you start working + + align:start position:0% +you know I mean once you start working + + + align:start position:0% +you know I mean once you start working +on stuff you know that tends to open up + + align:start position:0% +on stuff you know that tends to open up + + + align:start position:0% +on stuff you know that tends to open up +and I don't know so maybe maybe that' be + + align:start position:0% +and I don't know so maybe maybe that' be + + + align:start position:0% +and I don't know so maybe maybe that' be +it maybe I could ask a question which + + align:start position:0% +it maybe I could ask a question which + + + align:start position:0% +it maybe I could ask a question which +was what are the contextual conditions + + align:start position:0% +was what are the contextual conditions + + + align:start position:0% +was what are the contextual conditions +needed for I don't know reflective + + align:start position:0% +needed for I don't know reflective + + + align:start position:0% +needed for I don't know reflective +practice to work work well okay so we + + align:start position:0% +practice to work work well okay so we + + + align:start position:0% +practice to work work well okay so we +should put attention to the contextual + + align:start position:0% +should put attention to the contextual + + + align:start position:0% +should put attention to the contextual +conditions like maybe it doesn't work in + + align:start position:0% +conditions like maybe it doesn't work in + + + align:start position:0% +conditions like maybe it doesn't work in +the first two days making this process + + align:start position:0% +the first two days making this process + + + align:start position:0% +the first two days making this process +going + + align:start position:0% +going + + + align:start position:0% +going +forward that is a much better phrasing + + align:start position:0% +forward that is a much better phrasing + + + align:start position:0% +forward that is a much better phrasing +of what I intended to say + + align:start position:0% +of what I intended to say + + + align:start position:0% +of what I intended to say +actually about the context where you do + + align:start position:0% +actually about the context where you do + + + align:start position:0% +actually about the context where you do +it which I think is very important okay + + align:start position:0% +it which I think is very important okay + + + align:start position:0% +it which I think is very important okay +but what if you only have one + + align:start position:0% +but what if you only have one + + + align:start position:0% +but what if you only have one +day + + align:start position:0% + + + + align:start position:0% + +okay but we cannot we cannot solve this + + align:start position:0% +okay but we cannot we cannot solve this + + + align:start position:0% +okay but we cannot we cannot solve this +question this + + align:start position:0% +question this + + + align:start position:0% +question this +moment learning to ask the right + + align:start position:0% +moment learning to ask the right + + + align:start position:0% +moment learning to ask the right +questions learning to ask the right + + align:start position:0% +questions learning to ask the right + + + align:start position:0% +questions learning to ask the right +questions if we can learn how to ask the + + align:start position:0% +questions if we can learn how to ask the + + + align:start position:0% +questions if we can learn how to ask the +right + + align:start position:0% +right + + + align:start position:0% +right +questions yes okay great thank you very + + align:start position:0% +questions yes okay great thank you very + + + align:start position:0% +questions yes okay great thank you very +much yeah that's that's what because we + + align:start position:0% +much yeah that's that's what because we + + + align:start position:0% +much yeah that's that's what because we +can only control what we do do so if we + + align:start position:0% +can only control what we do do so if we + + + align:start position:0% +can only control what we do do so if we +if we have a problem to address in a + + align:start position:0% +if we have a problem to address in a + + + align:start position:0% +if we have a problem to address in a +community we're going we can only do we + + align:start position:0% +community we're going we can only do we + + + align:start position:0% +community we're going we can only do we +can only control our own approach so how + + align:start position:0% +can only control our own approach so how + + + align:start position:0% +can only control our own approach so how +do we make this common practice for + + align:start position:0% +do we make this common practice for + + + align:start position:0% +do we make this common practice for +us by asking the right questions how do + + align:start position:0% +us by asking the right questions how do + + + align:start position:0% +us by asking the right questions how do +we remember to ask the right questions + + align:start position:0% +we remember to ask the right questions + + + align:start position:0% +we remember to ask the right questions +to ourselves right yeah because I can't + + align:start position:0% +to ourselves right yeah because I can't + + + align:start position:0% +to ourselves right yeah because I can't +okay to think about going into community + + align:start position:0% +okay to think about going into community + + + align:start position:0% +okay to think about going into community +and get them all to do this is + + align:start position:0% +and get them all to do this is + + + align:start position:0% +and get them all to do this is +overwhelming for me right now cuz I my + + align:start position:0% +overwhelming for me right now cuz I my + + + align:start position:0% +overwhelming for me right now cuz I my +question was how do I make this a habit + + align:start position:0% +question was how do I make this a habit + + + align:start position:0% +question was how do I make this a habit +for me first you know if I can ask the + + align:start position:0% +for me first you know if I can ask the + + + align:start position:0% +for me first you know if I can ask the +right question maybe I can bring + + align:start position:0% +right question maybe I can bring + + + align:start position:0% +right question maybe I can bring +somebody on board with going into this + + align:start position:0% +somebody on board with going into this + + + align:start position:0% +somebody on board with going into this +whole process okay if I don't approach + + align:start position:0% +whole process okay if I don't approach + + + align:start position:0% +whole process okay if I don't approach +it you + + align:start position:0% +it you + + + align:start position:0% +it you +know okay so the the the capacity + + align:start position:0% +know okay so the the the capacity + + + align:start position:0% +know okay so the the the capacity +for asking the the right question is + + align:start position:0% +for asking the the right question is + + + align:start position:0% +for asking the the right question is +something that we make + + align:start position:0% +something that we make + + + align:start position:0% +something that we make +easier for one to reflect no to remember + + align:start position:0% +easier for one to reflect no to remember + + + align:start position:0% +easier for one to reflect no to remember +ask the right + + align:start position:0% +ask the right + + + align:start position:0% +ask the right +question okay and also to understand + + align:start position:0% +question okay and also to understand + + + align:start position:0% +question okay and also to understand +what is the yeah what is the right yeah + + align:start position:0% +what is the yeah what is the right yeah + + + align:start position:0% +what is the yeah what is the right yeah +how to ask the right question okay we + + align:start position:0% +how to ask the right question okay we + + + align:start position:0% +how to ask the right question okay we +have a new question here how to ask the + + align:start position:0% +have a new question here how to ask the + + + align:start position:0% +have a new question here how to ask the +right question but it's a good one we + + align:start position:0% +right question but it's a good one we + + + align:start position:0% +right question but it's a good one we +think should think about + + align:start position:0% +think should think about + + + align:start position:0% +think should think about +it that you you know the group that your + + align:start position:0% +it that you you know the group that your + + + align:start position:0% +it that you you know the group that your +work have some familiarity to the people + + align:start position:0% +work have some familiarity to the people + + + align:start position:0% +work have some familiarity to the people +you're working with um would that help + + align:start position:0% +you're working with um would that help + + + align:start position:0% +you're working with um would that help +you address them in a different way if + + align:start position:0% +you address them in a different way if + + + align:start position:0% +you address them in a different way if +you know the group have some idea the + + align:start position:0% +you know the group have some idea the + + + align:start position:0% +you know the group have some idea the +background of people that you're working + + align:start position:0% +background of people that you're working + + + align:start position:0% +background of people that you're working +with the the experience of scissor is + + align:start position:0% +with the the experience of scissor is + + + align:start position:0% +with the the experience of scissor is +that it's a almost a requirement people + + align:start position:0% +that it's a almost a requirement people + + + align:start position:0% +that it's a almost a requirement people +to share some kind of experience before + + align:start position:0% +to share some kind of experience before + + + align:start position:0% +to share some kind of experience before +for making the process as a group not + + align:start position:0% +for making the process as a group not + + + align:start position:0% +for making the process as a group not +necessarily + + align:start position:0% +necessarily + + + align:start position:0% +necessarily +for for working individually but for + + align:start position:0% +for for working individually but for + + + align:start position:0% +for for working individually but for +working as a group is required to share + + align:start position:0% +working as a group is required to share + + + align:start position:0% +working as a group is required to share +the same kind of experience or the same + + align:start position:0% +the same kind of experience or the same + + + align:start position:0% +the same kind of experience or the same +experience so I I think this if you + + align:start position:0% +experience so I I think this if you + + + align:start position:0% +experience so I I think this if you +think about this question how to make + + align:start position:0% +think about this question how to make + + + align:start position:0% +think about this question how to make +reflective practice common practice for + + align:start position:0% +reflective practice common practice for + + + align:start position:0% +reflective practice common practice for +ourselves from an individual level you + + align:start position:0% +ourselves from an individual level you + + + align:start position:0% +ourselves from an individual level you +know this what what nikisha and JY just + + align:start position:0% +know this what what nikisha and JY just + + + align:start position:0% +know this what what nikisha and JY just +mentioned really it's it's a learning + + align:start position:0% +mentioned really it's it's a learning + + + align:start position:0% +mentioned really it's it's a learning +from from this from what we've we see in + + align:start position:0% +from from this from what we've we see in + + + align:start position:0% +from from this from what we've we see in +these critical moments you know the + + align:start position:0% +these critical moments you know the + + + align:start position:0% +these critical moments you know the +questions some of these things help + + align:start position:0% +questions some of these things help + + + align:start position:0% +questions some of these things help +that's that's a lesson we get that's + + align:start position:0% +that's that's a lesson we get that's + + + align:start position:0% +that's that's a lesson we get that's +something we get that helps us begin to + + align:start position:0% +something we get that helps us begin to + + + align:start position:0% +something we get that helps us begin to +answer this question so try to focus on + + align:start position:0% +answer this question so try to focus on + + + align:start position:0% +answer this question so try to focus on +those types of + + align:start position:0% +those types of + + + align:start position:0% +those types of +things okay for name um and you said + + align:start position:0% +things okay for name um and you said + + + align:start position:0% +things okay for name um and you said +where we would where would we look um + + align:start position:0% +where we would where would we look um + + + align:start position:0% +where we would where would we look um +for these things and I think one of the + + align:start position:0% +for these things and I think one of the + + + align:start position:0% +for these things and I think one of the +of the things that I heard might Ezra + + align:start position:0% +of the things that I heard might Ezra + + + align:start position:0% +of the things that I heard might Ezra +who said it was um the critical moments + + align:start position:0% +who said it was um the critical moments + + + align:start position:0% +who said it was um the critical moments +were related to when the moment was + + align:start position:0% +were related to when the moment was + + + align:start position:0% +were related to when the moment was +relevant to the + + align:start position:0% +relevant to the + + + align:start position:0% +relevant to the +individual and so that's what I that's + + align:start position:0% +individual and so that's what I that's + + + align:start position:0% +individual and so that's what I that's +where I would + + align:start position:0% +where I would + + + align:start position:0% +where I would +look figure out how to + + align:start position:0% +look figure out how to + + + align:start position:0% +look figure out how to +make can you repeat please yeah that's + + align:start position:0% +make can you repeat please yeah that's + + + align:start position:0% +make can you repeat please yeah that's +um if we can you repeat please um you + + align:start position:0% +um if we can you repeat please um you + + + align:start position:0% +um if we can you repeat please um you +asked us where we would look yes to + + align:start position:0% +asked us where we would look yes to + + + align:start position:0% +asked us where we would look yes to +figure out how to make common practice + + align:start position:0% +figure out how to make common practice + + + align:start position:0% +figure out how to make common practice +more practical mhm uh I would look to + + align:start position:0% +more practical mhm uh I would look to + + + align:start position:0% +more practical mhm uh I would look to +moments of relevance for the + + align:start position:0% + + + + align:start position:0% + +individual okay any other idea + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +so you feel comfortable with this + + align:start position:0% + + + + align:start position:0% + +answers some other things come in mind + + align:start position:0% +answers some other things come in mind + + + align:start position:0% +answers some other things come in mind +for example X Esra had a question at the + + align:start position:0% + + + + align:start position:0% + +beginning remember should we come to + + align:start position:0% +beginning remember should we come to + + + align:start position:0% +beginning remember should we come to +class or not huh should he come to class + + align:start position:0% +class or not huh should he come to class + + + align:start position:0% +class or not huh should he come to class +or + + align:start position:0% +or + + + align:start position:0% +or +not okay I don't remember but you had a + + align:start position:0% +not okay I don't remember but you had a + + + align:start position:0% +not okay I don't remember but you had a +question I ask you wait for a moment + + align:start position:0% +question I ask you wait for a moment + + + align:start position:0% +question I ask you wait for a moment +because we are now trying to answer uh + + align:start position:0% +because we are now trying to answer uh + + + align:start position:0% +because we are now trying to answer uh +no it was about the the background the + + align:start position:0% +no it was about the the background the + + + align:start position:0% +no it was about the the background the +context of what's happening in our daily + + align:start position:0% +context of what's happening in our daily + + + align:start position:0% +context of what's happening in our daily +lives outside of class that affects + + align:start position:0% +lives outside of class that affects + + + align:start position:0% +lives outside of class that affects +where we + + align:start position:0% +where we + + + align:start position:0% +where we +the critical moments how we okay it's + + align:start position:0% +the critical moments how we okay it's + + + align:start position:0% +the critical moments how we okay it's +only about how how we Define the + + align:start position:0% +only about how how we Define the + + + align:start position:0% +only about how how we Define the +critical moments no it's about what we + + align:start position:0% +critical moments no it's about what we + + + align:start position:0% +critical moments no it's about what we +were what we're going through personally + + align:start position:0% +were what we're going through personally + + + align:start position:0% +were what we're going through personally +in our lives that may have impacted the + + align:start position:0% +in our lives that may have impacted the + + + align:start position:0% +in our lives that may have impacted the +yes IDE I I got it okay + + align:start position:0% +yes IDE I I got it okay + + + align:start position:0% +yes IDE I I got it okay +okay yes qu I had a thought on Rene's + + align:start position:0% +okay yes qu I had a thought on Rene's + + + align:start position:0% +okay yes qu I had a thought on Rene's +point which was maybe maybe we can't + + align:start position:0% +point which was maybe maybe we can't + + + align:start position:0% +point which was maybe maybe we can't +really go through the whole process of + + align:start position:0% +really go through the whole process of + + + align:start position:0% +really go through the whole process of +reflective practice quickly but is there + + align:start position:0% +reflective practice quickly but is there + + + align:start position:0% +reflective practice quickly but is there +a way convey the value of it quickly at + + align:start position:0% +a way convey the value of it quickly at + + + align:start position:0% +a way convey the value of it quickly at +least so at least people at least you + + align:start position:0% +least so at least people at least you + + + align:start position:0% +least so at least people at least you +get them hooked and like they kind of + + align:start position:0% +get them hooked and like they kind of + + + align:start position:0% +get them hooked and like they kind of +you know raises people's curiosity and + + align:start position:0% +you know raises people's curiosity and + + + align:start position:0% +you know raises people's curiosity and +say well H that's interesting maybe I'll + + align:start position:0% +say well H that's interesting maybe I'll + + + align:start position:0% +say well H that's interesting maybe I'll +stick it out for two days or whatever it + + align:start position:0% +stick it out for two days or whatever it + + + align:start position:0% +stick it out for two days or whatever it +takes to really start to get into it to + + align:start position:0% +takes to really start to get into it to + + + align:start position:0% +takes to really start to get into it to +the point where you can feel you can + + align:start position:0% +the point where you can feel you can + + + align:start position:0% +the point where you can feel you can +feel the value you know maybe like our + + align:start position:0% +feel the value you know maybe like our + + + align:start position:0% +feel the value you know maybe like our +day four period when you kind of you + + align:start position:0% +day four period when you kind of you + + + align:start position:0% +day four period when you kind of you +know really + + align:start position:0% +know really + + + align:start position:0% +know really +engage I don't know yeah I'm not sure + + align:start position:0% +engage I don't know yeah I'm not sure + + + align:start position:0% +engage I don't know yeah I'm not sure +how to do that but + + align:start position:0% + + + + align:start position:0% + +okay so I think that we + + align:start position:0% +okay so I think that we + + + align:start position:0% +okay so I think that we +have um it's related actually with the + + align:start position:0% +have um it's related actually with the + + + align:start position:0% +have um it's related actually with the +type of language that you use to + + align:start position:0% +type of language that you use to + + + align:start position:0% +type of language that you use to +communicate what is reflective practice + + align:start position:0% +communicate what is reflective practice + + + align:start position:0% +communicate what is reflective practice +my question is there a way to + + align:start position:0% +my question is there a way to + + + align:start position:0% +my question is there a way to +communicate in a different way that can + + align:start position:0% +communicate in a different way that can + + + align:start position:0% +communicate in a different way that can +attract more + + align:start position:0% +attract more + + + align:start position:0% +attract more +people to understand and to to + + align:start position:0% +people to understand and to to + + + align:start position:0% +people to understand and to to +understand and to make it a more common + + align:start position:0% +understand and to make it a more common + + + align:start position:0% +understand and to make it a more common +and useful thing in people's lives and + + align:start position:0% +and useful thing in people's lives and + + + align:start position:0% +and useful thing in people's lives and +not so much an abstract thinking about a + + align:start position:0% +not so much an abstract thinking about a + + + align:start position:0% +not so much an abstract thinking about a +situation and then you need to + + align:start position:0% +situation and then you need to + + + align:start position:0% +situation and then you need to +just thinking about the the way you + + align:start position:0% +just thinking about the the way you + + + align:start position:0% +just thinking about the the way you +communicate the way the way that you use + + align:start position:0% +communicate the way the way that you use + + + align:start position:0% +communicate the way the way that you use +to communicate what you want + + align:start position:0% +to communicate what you want + + + align:start position:0% +to communicate what you want +to develop at a common practice okay the + + align:start position:0% +to develop at a common practice okay the + + + align:start position:0% +to develop at a common practice okay the +vocabulary the kind of words are uses no + + align:start position:0% + + + + align:start position:0% + +okay not the vocabulary the mediums you + + align:start position:0% +okay not the vocabulary the mediums you + + + align:start position:0% +okay not the vocabulary the mediums you +use to + + align:start position:0% +use to + + + align:start position:0% +use to +address the + + align:start position:0% + + + + align:start position:0% + +the mediums you use it's not only the + + align:start position:0% +the mediums you use it's not only the + + + align:start position:0% +the mediums you use it's not only the +vocabulary it's how how you communicate + + align:start position:0% +vocabulary it's how how you communicate + + + align:start position:0% +vocabulary it's how how you communicate +if you communicate through workshops if + + align:start position:0% +if you communicate through workshops if + + + align:start position:0% +if you communicate through workshops if +you communicate through media + + align:start position:0% +you communicate through media + + + align:start position:0% +you communicate through media +um commun type of communication if you + + align:start position:0% +um commun type of communication if you + + + align:start position:0% +um commun type of communication if you +just what is what is + + align:start position:0% +just what is what is + + + align:start position:0% +just what is what is +the is the the channel the channel to + + align:start position:0% +the is the the channel the channel to + + + align:start position:0% +the is the the channel the channel to +get to people and okay what is the would + + align:start position:0% +get to people and okay what is the would + + + align:start position:0% +get to people and okay what is the would +that be models would that be the + + align:start position:0% +that be models would that be the + + + align:start position:0% +that be models would that be the +different models they use + + align:start position:0% +different models they use + + + align:start position:0% +different models they use +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +depending on the + + align:start position:0% +depending on the + + + align:start position:0% +depending on the +group we should be aware of that because + + align:start position:0% +group we should be aware of that because + + + align:start position:0% +group we should be aware of that because +different people prefer different ways + + align:start position:0% +different people prefer different ways + + + align:start position:0% +different people prefer different ways +of expressions in in media yes okay + + align:start position:0% +of expressions in in media yes okay + + + align:start position:0% +of expressions in in media yes okay +thank you very much the best one um I + + align:start position:0% +thank you very much the best one um I + + + align:start position:0% +thank you very much the best one um I +was just going to say that maybe one way + + align:start position:0% +was just going to say that maybe one way + + + align:start position:0% +was just going to say that maybe one way +to try to answer this question of how to + + align:start position:0% +to try to answer this question of how to + + + align:start position:0% +to try to answer this question of how to +make the practice more something that + + align:start position:0% +make the practice more something that + + + align:start position:0% +make the practice more something that +comes in your daily life would be to try + + align:start position:0% +comes in your daily life would be to try + + + align:start position:0% +comes in your daily life would be to try +and figure + + align:start position:0% +and figure + + + align:start position:0% +and figure +out which of the exercises or what of + + align:start position:0% +out which of the exercises or what of + + + align:start position:0% +out which of the exercises or what of +the exercises you found to be most + + align:start position:0% +the exercises you found to be most + + + align:start position:0% +the exercises you found to be most +valuable and start with trying to + + align:start position:0% +valuable and start with trying to + + + align:start position:0% +valuable and start with trying to +incorporate those kinds of things into + + align:start position:0% +incorporate those kinds of things into + + + align:start position:0% +incorporate those kinds of things into +your dat like which are the ones that + + align:start position:0% +your dat like which are the ones that + + + align:start position:0% +your dat like which are the ones that +you could do on on a regular + + align:start position:0% +you could do on on a regular + + + align:start position:0% +you could do on on a regular +basis that that would have the most the + + align:start position:0% +basis that that would have the most the + + + align:start position:0% +basis that that would have the most the +most impact + + align:start position:0% +most impact + + + align:start position:0% +most impact +on okay the actual + + align:start position:0% +on okay the actual + + + align:start position:0% +on okay the actual +exercises you are thinking about the + + align:start position:0% +exercises you are thinking about the + + + align:start position:0% +exercises you are thinking about the +exercise we made in the + + align:start position:0% + + + + align:start position:0% + +course like with framing or model + + align:start position:0% +course like with framing or model + + + align:start position:0% +course like with framing or model +models things like that and try to to + + align:start position:0% +models things like that and try to to + + + align:start position:0% +models things like that and try to to +use what we have learned with this + + align:start position:0% +use what we have learned with this + + + align:start position:0% +use what we have learned with this +exercise in Practical situation we are + + align:start position:0% +exercise in Practical situation we are + + + align:start position:0% +exercise in Practical situation we are +facing okay like which of those do you + + align:start position:0% +facing okay like which of those do you + + + align:start position:0% +facing okay like which of those do you +feel like you got the most value out of + + align:start position:0% +feel like you got the most value out of + + + align:start position:0% +feel like you got the most value out of +because each one is going to take you + + align:start position:0% +because each one is going to take you + + + align:start position:0% +because each one is going to take you +some time to do so which one did you + + align:start position:0% +some time to do so which one did you + + + align:start position:0% +some time to do so which one did you +feel like really gave you the most bank + + align:start position:0% +feel like really gave you the most bank + + + align:start position:0% +feel like really gave you the most bank +for your buck that you could then go and + + align:start position:0% +for your buck that you could then go and + + + align:start position:0% +for your buck that you could then go and +Implement okay great because this is the + + align:start position:0% +Implement okay great because this is the + + + align:start position:0% +Implement okay great because this is the +starting point no you need a starting + + align:start position:0% +starting point no you need a starting + + + align:start position:0% +starting point no you need a starting +point for improving your the use of + + align:start position:0% +point for improving your the use of + + + align:start position:0% +point for improving your the use of +refective practice not not the theory in + + align:start position:0% +refective practice not not the theory in + + + align:start position:0% +refective practice not not the theory in +general but one point where you began to + + align:start position:0% +general but one point where you began to + + + align:start position:0% +general but one point where you began to +practice this it's no okay thank you + + align:start position:0% +practice this it's no okay thank you + + + align:start position:0% +practice this it's no okay thank you +very much let's go for a break a very + + align:start position:0% +very much let's go for a break a very + + + align:start position:0% +very much let's go for a break a very +brief break because we need to make + + align:start position:0% +brief break because we need to make + + + align:start position:0% +brief break because we need to make +another exercise before to end the + + align:start position:0% +another exercise before to end the + + + align:start position:0% +another exercise before to end the +course okay so do we have how long five + + align:start position:0% +course okay so do we have how long five + + + align:start position:0% +course okay so do we have how long five +minutes please yeah really five minutes + + align:start position:0% + + + + align:start position:0% + +the + + align:start position:0% + + + + align:start position:0% + +the the + + align:start position:0% +the the + + + align:start position:0% +the the +purpose the + + align:start position:0% +purpose the + + + align:start position:0% +purpose the +purpose is not to give + + align:start position:0% +purpose is not to give + + + align:start position:0% +purpose is not to give +you + + align:start position:0% +you + + + align:start position:0% +you +a + + align:start position:0% +a + + + align:start position:0% +a +extensive vision of what is happening + + align:start position:0% +extensive vision of what is happening + + + align:start position:0% +extensive vision of what is happening +just try + + align:start position:0% +just try + + + align:start position:0% +just try +to to understand the context + + align:start position:0% + + + + align:start position:0% + +where 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+ + align:start position:0% +crowds it's about M exclusively in their +minds and not other people don't share + + align:start position:0% +minds and not other people don't share + + + align:start position:0% +minds and not other people don't share +this knowledge and combining all this to + + align:start position:0% +this knowledge and combining all this to + + + align:start position:0% +this knowledge and combining all this to +make + + align:start position:0% +make + + + align:start position:0% +make +decisions it's very interesting you can + + align:start position:0% +decisions it's very interesting you can + + + align:start position:0% +decisions it's very interesting you can +go into the + + align:start position:0% +go into the + + + align:start position:0% +go into the +I electronic Market to understand how it + + align:start position:0% +I electronic Market to understand how it + + + align:start position:0% +I electronic Market to understand how it +works okay it's like people 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the + + + align:start position:0% +conceptual Innovation is the +driver + + align:start position:0% +driver + + + align:start position:0% +driver +what's pulling the process forward + + align:start position:0% +what's pulling the process forward + + + align:start position:0% +what's pulling the process forward +is the capacity of combining a + + align:start position:0% +is the capacity of combining a + + + align:start position:0% +is the capacity of combining a +different different kinds of of + + align:start position:0% +different different kinds of of + + + align:start position:0% +different different kinds of of +Technologies and this combination is + + align:start position:0% +Technologies and this combination is + + + align:start position:0% +Technologies and this combination is +made + + align:start position:0% +made + + + align:start position:0% +made +in is made by + + align:start position:0% + + + + align:start position:0% + +the creation of New Concept of products + + 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Ary will be much more important + + align:start position:0% +after3 Ary will be much more important + + + align:start position:0% +after3 Ary will be much more important +in the future okay let's + + align:start position:0% + + + + align:start position:0% + +go new requirements of collaborative + + align:start position:0% +go new requirements of collaborative + + + align:start position:0% +go new requirements of collaborative +work Global and local issues are getting + + align:start position:0% +work Global and local issues are getting + + + align:start position:0% +work Global and local issues are getting +mixing new issues are + + align:start position:0% +mixing new issues are + + + align:start position:0% +mixing new issues are +emerging that not fit in any + + align:start position:0% +emerging that not fit in any + + + align:start position:0% +emerging that not fit in any +profession + + align:start position:0% +profession + + + align:start position:0% +profession +okay local 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+thank you +customers the 10 phases of + + align:start position:0% +customers the 10 phases of + + + align:start position:0% +customers the 10 phases of +innovation from + + align:start position:0% +innovation from + + + align:start position:0% +innovation from +id id Ido no + + align:start position:0% + + + + align:start position:0% + +yes in Spanish I say Ideo it's Tom + + align:start position:0% +yes in Spanish I say Ideo it's Tom + + + align:start position:0% +yes in Spanish I say Ideo it's Tom +Kelly the number one in innovation in + + align:start position:0% +Kelly the number one in innovation in + + + align:start position:0% +Kelly the number one in innovation in +the United States you can see that the + + align:start position:0% +the United States you can see that the + + + align:start position:0% +the United States you can see that the +way they think has a lot of the way we + + align:start position:0% +way they think has a lot of the way we + + + align:start position:0% +way they think has a lot of the way we +think in reflective practice + + align:start position:0% +think in reflective practice + + + align:start position:0% +think in reflective practice +okay how to combine ideas how to + + align:start position:0% +okay how to combine ideas how to + + + align:start position:0% +okay how to combine ideas how to +construct on partial + + align:start position:0% +construct on partial + + + align:start position:0% +construct on partial +ideas how to reinterpret the ideas that + + align:start position:0% +ideas how to reinterpret the ideas that + + + align:start position:0% +ideas how to reinterpret the ideas that +other people brought to make it to fit + + align:start position:0% +other people brought to make it to fit + + + align:start position:0% +other people brought to make it to fit +with my idea or how may I to reinterpret + + align:start position:0% +with my idea or how may I to reinterpret + + + align:start position:0% +with my idea or how may I to reinterpret +my idea to make it to fit with the + + align:start position:0% +my idea to make it to fit with the + + + align:start position:0% +my idea to make it to fit with the +others how to be flexible interacting + + align:start position:0% +others how to be flexible interacting + + + align:start position:0% +others how to be flexible interacting +professionally how to adapt mentally to + + align:start position:0% +professionally how to adapt mentally to + + + align:start position:0% +professionally how to adapt mentally to +the different situation that I am + + align:start position:0% +the different situation that I am + + + align:start position:0% +the different situation that I am +facing the other one is source of power + + align:start position:0% +facing the other one is source of power + + + align:start position:0% +facing the other one is source of power +is the most similar book I have read to + + align:start position:0% +is the most similar book I have read to + + + align:start position:0% +is the most similar book I have read to +the reflective + + align:start position:0% +the reflective + + + align:start position:0% +the reflective +practitioner it's about how people think + + align:start position:0% +practitioner it's about how people think + + + align:start position:0% +practitioner it's about how people think +think in + + align:start position:0% +think in + + + align:start position:0% +think in +action it's about the firefighters I + + align:start position:0% +action it's about the firefighters I + + + align:start position:0% +action it's about the firefighters I +showed the first day okay and the word + + align:start position:0% +showed the first day okay and the word + + + align:start position:0% +showed the first day okay and the word +is flat there is a part of the + + align:start position:0% +is flat there is a part of the + + + align:start position:0% +is flat there is a part of the +reflection of Thomas fredman dedicated + + align:start position:0% +reflection of Thomas fredman dedicated + + + align:start position:0% +reflection of Thomas fredman dedicated +to conceptual + + align:start position:0% +to conceptual + + + align:start position:0% +to conceptual +Innovation a whole new mind is about the + + align:start position:0% +Innovation a whole new mind is about the + + + align:start position:0% +Innovation a whole new mind is about the +role of + + align:start position:0% +role of + + + align:start position:0% +role of +concept in the process of create + + align:start position:0% +concept in the process of create + + + align:start position:0% +concept in the process of create +creation infotopia is the new + + align:start position:0% +creation infotopia is the new + + + align:start position:0% +creation infotopia is the new +environment that is emerging and how we + + align:start position:0% +environment that is emerging and how we + + + align:start position:0% +environment that is emerging and how we +need + + align:start position:0% +need + + + align:start position:0% +need +to to be aware of our the way we are + + align:start position:0% +to to be aware of our the way we are + + + align:start position:0% +to to be aware of our the way we are +framing the problems the way we are + + align:start position:0% +framing the problems the way we are + + + align:start position:0% +framing the problems the way we are +thinking about the situation for + + align:start position:0% +thinking about the situation for + + + align:start position:0% +thinking about the situation for +combining with other people and I am + + align:start position:0% +combining with other people and I am + + + align:start position:0% +combining with other people and I am +sure that we could have another examples + + align:start position:0% +sure that we could have another examples + + + align:start position:0% +sure that we could have another examples +of + + align:start position:0% +of + + + align:start position:0% +of +that + + align:start position:0% +that + + + align:start position:0% +that +my assumption + + align:start position:0% +my assumption + + + align:start position:0% +my assumption +hypothesis in this case because I am + + align:start position:0% +hypothesis in this case because I am + + + align:start position:0% +hypothesis in this case because I am +aware of that is that main idea many + + align:start position:0% +aware of that is that main idea many + + + align:start position:0% +aware of that is that main idea many +ideas of reflective practice are being + + align:start position:0% +ideas of reflective practice are being + + + align:start position:0% +ideas of reflective practice are being +used by these authors and they are find + + align:start position:0% +used by these authors and they are find + + + align:start position:0% +used by these authors and they are find +finding very very powerful for + + align:start position:0% +finding very very powerful for + + + align:start position:0% +finding very very powerful for +them okay so in spite of that reflective + + align:start position:0% +them okay so in spite of that reflective + + + align:start position:0% +them okay so in spite of that reflective +practice was developed in the 60s 70s + + align:start position:0% +practice was developed in the 60s 70s + + + align:start position:0% +practice was developed in the 60s 70s +and 80s its importance is growing in + + align:start position:0% +and 80s its importance is growing in + + + align:start position:0% +and 80s its importance is growing in +this + + align:start position:0% +this + + + align:start position:0% +this +Century okay yes are those other setting + + align:start position:0% +Century okay yes are those other setting + + + align:start position:0% +Century okay yes are those other setting +sh no no one + + align:start position:0% +sh no no one + + + align:start position:0% +sh no no one +SES but it doesn't matter because if you + + align:start position:0% +SES but it doesn't matter because if you + + + align:start position:0% +SES but it doesn't matter because if you +analyze the way they + + align:start position:0% +analyze the way they + + + align:start position:0% +analyze the way they +are presented their ideas you can find + + align:start position:0% +are presented their ideas you can find + + + align:start position:0% +are presented their ideas you can find +similarities but they they the people + + align:start position:0% +similarities but they they the people + + + align:start position:0% +similarities but they they the people +who sites Shan is the people who are + + align:start position:0% +who sites Shan is the people who are + + + align:start position:0% +who sites Shan is the people who are +dedicated to reflection methodology + + align:start position:0% +dedicated to reflection methodology + + + align:start position:0% +dedicated to reflection methodology +most of them because + + align:start position:0% +most of them because + + + align:start position:0% +most of them because +the the idea of reflective practice was + + align:start position:0% +the the idea of reflective practice was + + + align:start position:0% +the the idea of reflective practice was +interpreted as the practice of + + align:start position:0% +interpreted as the practice of + + + align:start position:0% +interpreted as the practice of +reflection that's not exactly the same + + align:start position:0% +reflection that's not exactly the same + + + align:start position:0% +reflection that's not exactly the same +it's just one part of reflective + + align:start position:0% +it's just one part of reflective + + + align:start position:0% +it's just one part of reflective +practice the practice of + + align:start position:0% +practice the practice of + + + align:start position:0% +practice the practice of +reflection okay the practice of + + align:start position:0% +reflection okay the practice of + + + align:start position:0% +reflection okay the practice of +reflection is the stepping back to one + + align:start position:0% +reflection is the stepping back to one + + + align:start position:0% +reflection is the stepping back to one +experience to retrieve knowledge and for + + align:start position:0% +experience to retrieve knowledge and for + + + align:start position:0% +experience to retrieve knowledge and for +for understanding better it's very + + align:start position:0% +for understanding better it's very + + + align:start position:0% +for understanding better it's very +useful for these two purpose and it's + + align:start position:0% +useful for these two purpose and it's + + + align:start position:0% +useful for these two purpose and it's +very useful to for learning to be a + + align:start position:0% +very useful to for learning to be a + + + align:start position:0% +very useful to for learning to be a +reflective practitioner to think in + + align:start position:0% +reflective practitioner to think in + + + align:start position:0% +reflective practitioner to think in +action to improve the way we think in + + align:start position:0% +action to improve the way we think in + + + align:start position:0% +action to improve the way we think in +action but the idea of Shan is basically + + align:start position:0% +action but the idea of Shan is basically + + + align:start position:0% +action but the idea of Shan is basically +this last phrase how to improve the way + + align:start position:0% +this last phrase how to improve the way + + + align:start position:0% +this last phrase how to improve the way +we think in + + align:start position:0% +we think in + + + align:start position:0% +we think in +action + + align:start position:0% +action + + + align:start position:0% +action +okay yeah and I have some question for + + align:start position:0% +okay yeah and I have some question for + + + align:start position:0% +okay yeah and I have some question for +you about this + + align:start position:0% + + + + align:start position:0% + +how many cards you may + + align:start position:0% +how many cards you may + + + align:start position:0% +how many cards you may +receive we we we need to simplify the + + align:start position:0% +receive we we we need to simplify the + + + align:start position:0% +receive we we we need to simplify the +exercise + + align:start position:0% + + + + align:start position:0% + +no yeah okay + + align:start position:0% + + + + align:start position:0% + +please each one of + + align:start position:0% +please each one of + + + align:start position:0% +please each one of +you with we have thought during the + + align:start position:0% +you with we have thought during the + + + align:start position:0% +you with we have thought during the +course combining with some of these + + align:start position:0% +course combining with some of these + + + align:start position:0% +course combining with some of these +ideas I + + align:start position:0% +ideas I + + + align:start position:0% +ideas I +presented + + align:start position:0% +presented + + + align:start position:0% +presented +each one will write three + + align:start position:0% +each one will write three + + + align:start position:0% +each one will write three +cards yes this course will required + + align:start position:0% +cards yes this course will required + + + align:start position:0% +cards yes this course will required +to to think hard until the last minute + + align:start position:0% + + + + align:start position:0% + +okay how do you see the + + align:start position:0% +okay how do you see the + + + align:start position:0% +okay how do you see the +future of this the ideas of this + + align:start position:0% +future of this the ideas of this + + + align:start position:0% +future of this the ideas of this +course in your practice or + + align:start position:0% +course in your practice or + + + align:start position:0% +course in your practice or +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +in + + align:start position:0% + + + + align:start position:0% + +yes in + + align:start position:0% +yes in + + + align:start position:0% +yes in +the this + + align:start position:0% + + + + align:start position:0% + +one to visual is the future of reflect + + align:start position:0% +one to visual is the future of reflect + + + align:start position:0% +one to visual is the future of reflect +of reflective + + align:start position:0% +of reflective + + + align:start position:0% +of reflective +practice what possibilities are open for + + align:start position:0% +practice what possibilities are open for + + + align:start position:0% +practice what possibilities are open for +reflective pract in this new environment + + align:start position:0% +reflective pract in this new environment + + + align:start position:0% +reflective pract in this new environment +it's + + align:start position:0% + + + + align:start position:0% + +okay okay what future do you see for the + + align:start position:0% +okay okay what future do you see for the + + + align:start position:0% +okay okay what future do you see for the +ideas this ideas developed that + + align:start position:0% +ideas this ideas developed that + + + align:start position:0% +ideas this ideas developed that +time okay three three cards + + align:start position:0% + + + + align:start position:0% + +please three you can put your name if + + align:start position:0% +please three you can put your name if + + + align:start position:0% +please three you can put your name if +you + + align:start position:0% +you + + + align:start position:0% +you +want okay but how you see the future of + + align:start position:0% +want okay but how you see the future of + + + align:start position:0% +want okay but how you see the future of +reflective practice + + align:start position:0% + + + + align:start position:0% + +with + + align:start 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position:0% +wrote connect your own own you can + + + align:start position:0% +wrote connect your own own you can +connect to your own practice as a + + align:start position:0% +connect to your own practice as a + + + align:start position:0% +connect to your own practice as a +reference okay okay but we are trying to + + align:start position:0% +reference okay okay but we are trying to + + + align:start position:0% +reference okay okay but we are trying to +to understand the future of of + + align:start position:0% +to understand the future of of + + + align:start position:0% +to understand the future of of +reflective practice in general okay the + + align:start position:0% +reflective practice in general okay the + + + align:start position:0% +reflective practice in general okay the +idea of this course okay okay + + align:start position:0% + + + + align:start position:0% + +please please you have five + + align:start position:0% +please please you have five + + + align:start position:0% +please please you have five +minutes yes you know that the production + + align:start position:0% +minutes yes you know that the production + + + align:start position:0% +minutes yes you know that the production +of ideas doesn't depend of + + align:start position:0% +of ideas doesn't depend of + + + align:start position:0% +of ideas doesn't depend of +time it's a great + + align:start position:0% +time it's a great + + + align:start position:0% +time it's a great +thing + + align:start position:0% + + + + align:start position:0% + +yes very fast they question is that we + + align:start position:0% +yes very fast they question is that we + + + align:start position:0% +yes very fast they question is that we +just don't pick them at the moment okay + + align:start position:0% +just don't pick them at the moment okay + + + align:start position:0% +just don't pick them at the moment okay +okay the first glance that + + align:start position:0% +okay the first glance that + + + align:start position:0% +okay the first glance that +you the first fragment of idea that pass + + align:start position:0% +you the first fragment of idea that pass + + + align:start position:0% +you the first fragment of idea that pass +through your mind just write okay just + + align:start position:0% +through your mind just write okay just + + + align:start position:0% +through your mind just write okay just +pick + + align:start position:0% +pick + + + align:start position:0% +pick +it don't s much because the first glance + + align:start position:0% +it don't s much because the first glance + + + align:start position:0% +it don't s much because the first glance +is the best idea most of the times okay + + align:start position:0% +is the best idea most of the times okay + + + align:start position:0% +is the best idea most of the times okay +yes yes for because the inconscious is + + align:start position:0% +yes yes for because the inconscious is + + + align:start position:0% +yes yes for because the inconscious is +very very powerful in these things in + + align:start position:0% +very very powerful in these things in + + + align:start position:0% +very very powerful in these things in +very fast + + align:start position:0% + + + + align:start position:0% + +okay the best way I find for doing this + + align:start position:0% +okay the best way I find for doing this + + + align:start position:0% +okay the best way I find for doing this +very fast is the first the first idea I + + align:start position:0% +very fast is the first the first idea I + + + align:start position:0% +very fast is the first the first idea I +just write it and just and after that I + + align:start position:0% +just write it and just and after that I + + + align:start position:0% +just write it and just and after that I +discard it if it was not it if it were + + align:start position:0% +discard it if it was not it if it were + + + align:start position:0% +discard it if it was not it if it were +not this idea what new idea should be so + + align:start position:0% +not this idea what new idea should be so + + + align:start position:0% +not this idea what new idea should be so +I put my mind blank again and a new idea + + align:start position:0% +I put my mind blank again and a new idea + + + align:start position:0% +I put my mind blank again and a new idea +comes + + align:start position:0% +comes + + + align:start position:0% +comes +up rapid prototyping mean huh rapid + + align:start position:0% +up rapid prototyping mean huh rapid + + + align:start position:0% +up rapid prototyping mean huh rapid +prototyping I don't know the the the + + align:start position:0% +prototyping I don't know the the the + + + align:start position:0% +prototyping I don't know the the the +name I is the the method I use in my + + align:start position:0% +name I is the the method I use in my + + + align:start position:0% +name I is the the method I use in my +workshops + + align:start 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yes + + + align:start position:0% +yes yes +okay La + + align:start position:0% +okay La + + + align:start position:0% +okay La +see lapis + + align:start position:0% + + + + align:start position:0% + +no okay + + align:start position:0% + + + + align:start position:0% + +yeah it's the only way you can produce + + align:start position:0% +yeah it's the only way you can produce + + + align:start position:0% +yeah it's the only way you can produce +100 ideas in one + + align:start position:0% +100 ideas in one + + + align:start position:0% +100 ideas in one +hour okay + + align:start position:0% +hour okay + + + align:start position:0% +hour okay +you you look + + align:start position:0% +you you look + + + align:start position:0% +you you look +at + + align:start position:0% + + + + align:start position:0% + +okay foree + + align:start position:0% + + + + align:start position:0% + +excuse + + align:start position:0% +excuse + + + align:start position:0% +excuse +me we had to stop it 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+ + + align:start position:0% +it no p no +P SC no P + + align:start position:0% +P SC no P + + + align:start position:0% +P SC no P +SC you have don't think just + + align:start position:0% + + + + align:start position:0% + +right I real the question I answering + + align:start position:0% +right I real the question I answering + + + align:start position:0% +right I real the question I answering +more is what what possibilities does + + align:start position:0% +more is what what possibilities does + + + align:start position:0% +more is what what possibilities does +reflective practice open in the + + align:start position:0% +reflective practice open in the + + + align:start position:0% +reflective practice open in the +environment is that okay + + align:start position:0% +environment is that okay + + + align:start position:0% +environment is that okay +okay yes + + align:start position:0% +okay yes + + + align:start position:0% +okay yes +I yes it's the same it's it's another + + align:start position:0% +I yes it's the same it's it's another + + + align:start position:0% +I yes it's the same it's it's another +door for looking at the same idea we + + align:start position:0% +door for looking at the same idea we + + + align:start position:0% +door for looking at the same idea we +were trying to to + + align:start position:0% +were trying to to + + + align:start position:0% +were trying to to +obser it's more reflective + + align:start position:0% +obser it's more reflective + + + align:start position:0% +obser it's more reflective +pring refective practices sort of okay + + align:start position:0% +pring refective practices sort of okay + + + align:start position:0% +pring refective practices sort of okay +but if it is the c it will it will be + + align:start position:0% +but if it is the c it will it will be + + + align:start position:0% +but if it is the c it will it will be +part of this reality and this part will + + align:start position:0% +part of this reality and this part will + + + align:start position:0% +part of this reality and this part will +be a new possibility for it okay yeah + + align:start position:0% +be a new possibility for it okay yeah + + + align:start position:0% +be a new possibility for it okay yeah +already + + align:start position:0% +already + + + align:start position:0% +already +Yes can + + align:start position:0% +Yes can + + + align:start position:0% +Yes can +we okay we we need to work + + align:start position:0% +we okay we we need to work + + + align:start position:0% +we okay we we need to work +very no we have not we have eight + + align:start position:0% +very no we have not we have eight + + + align:start position:0% +very no we have not we have eight +minutes okay we we'll + + align:start position:0% +minutes okay we we'll + + + align:start position:0% +minutes okay we we'll +finish 12 less 15 because you need to + + align:start position:0% +finish 12 less 15 because you need to + + + align:start position:0% +finish 12 less 15 because you need to +make the evaluation of the curse and we + + align:start position:0% +make the evaluation of the curse and we + + + align:start position:0% +make the evaluation of the curse and we +will not be here in the in the classroom + + align:start position:0% +will not be here in the in the classroom + + + align:start position:0% +will not be here in the in the classroom +as you are evaluating the course okay so + + align:start position:0% +as you are evaluating the course okay so + + + align:start position:0% +as you are evaluating the course okay so +we have only 8 minutes okay let's talk + + align:start position:0% +we have only 8 minutes okay let's talk + + + align:start position:0% +we have only 8 minutes okay let's talk +about + + align:start position:0% + + + + align:start position:0% + +that must faay with + + align:start position:0% +that must faay with + + + align:start position:0% +that must faay with +that yes can you move it + + align:start position:0% +that yes can you move it + + + align:start position:0% +that yes can you move it +okay okay + + align:start position:0% + + + + align:start position:0% + +let's you will give us your cards after + + align:start position:0% +let's you will give us your cards after + + + align:start position:0% +let's you will give us your cards after +okay but + + align:start position:0% +okay but + + + align:start position:0% +okay but +please the most important idea of the + + align:start position:0% +please the most important idea of the + + + align:start position:0% +please the most important idea of the +three + + align:start position:0% +three + + + align:start position:0% +three +cards please tell + + align:start position:0% +cards please tell + + + align:start position:0% +cards please tell +us one yes if you want you can talk + + align:start position:0% +us one yes if you want you can talk + + + align:start position:0% +us one yes if you want you can talk +about more than one but first one idea + + align:start position:0% +about more than one but first one idea + + + align:start position:0% +about more than one but first one idea +of the three + + align:start position:0% +of the three + + + align:start position:0% +of the three +we will work with the cars after the + + align:start position:0% +we will work with the cars after the + + + align:start position:0% +we will work with the cars after the +first I'm not clear what just share one + + align:start position:0% +first I'm not clear what just share one + + + align:start position:0% +first I'm not clear what just share one +of okay + + align:start position:0% + + + + align:start position:0% + +okay oh you're asking no no I don't no I + + align:start position:0% +okay oh you're asking no no I don't no I + + + align:start position:0% +okay oh you're asking no no I don't no I +I I I was looking at you because you we + + align:start position:0% +I I I was looking at you because you we + + + align:start position:0% +I I I was looking at you because you we +were trying to understand what I'm + + align:start position:0% +were trying to understand what I'm + + + align:start position:0% +were trying to understand what I'm +supposed to do okay and who wants to + + align:start position:0% +supposed to do okay and who wants to + + + align:start position:0% +supposed to do okay and who wants to +begin I'll begin okay um I think that um + + align:start position:0% +begin I'll begin okay um I think that um + + + align:start position:0% +begin I'll begin okay um I think that um +reflective practice can improve + + align:start position:0% +reflective practice can improve + + + align:start position:0% +reflective practice can improve +organizational institutional + + align:start position:0% +organizational institutional + + + align:start position:0% +organizational institutional +efficiency can improve organizational + + align:start position:0% +efficiency can improve organizational + + + align:start position:0% +efficiency can improve organizational +and institutional + + align:start position:0% +and institutional + + + align:start position:0% +and institutional +efficiency okay thank + + align:start position:0% +efficiency okay thank + + + align:start position:0% +efficiency okay thank +you it's similar to the kind of + + align:start position:0% +you it's similar to the kind of + + + align:start position:0% +you it's similar to the kind of +formulation you was thinking before + + align:start position:0% +formulation you was thinking before + + + align:start position:0% +formulation you was thinking before +okay is a possible to + + align:start position:0% + + + + align:start position:0% + +build can you um is a possible blueprint + + align:start position:0% +build can you um is a possible blueprint + + + align:start position:0% +build can you um is a possible blueprint +to be used for building the Str + + align:start position:0% +to be used for building the Str + + + align:start position:0% +to be used for building the Str +Community organization um a what + + align:start position:0% +Community organization um a what + + + align:start position:0% +Community organization um a what +community a strengthen strengthen okay + + align:start position:0% +community a strengthen strengthen okay + + + align:start position:0% +community a strengthen strengthen okay +great okay CIA + + align:start position:0% + + + + align:start position:0% + +um reflective reflective practice um + + align:start position:0% +um reflective reflective practice um + + + align:start position:0% +um reflective reflective practice um +would cause can cause or is + + align:start position:0% +would cause can cause or is + + + align:start position:0% +would cause can cause or is +causing an intermediate process of + + align:start position:0% +causing an intermediate process of + + + align:start position:0% +causing an intermediate process of +conflict of + + align:start position:0% +conflict of + + + align:start position:0% +conflict of +paradigms par paradig paradig okay + + align:start position:0% +paradigms par paradig paradig okay + + + align:start position:0% +paradigms par paradig paradig okay +paradig + + align:start position:0% + + + + align:start position:0% + +yes I wrote + + align:start position:0% +yes I wrote + + + align:start position:0% +yes I wrote +down to write to finish to write + + align:start position:0% +down to write to finish to write + + + align:start position:0% +down to write to finish to write +intermediate process mhm of conflict of + + align:start position:0% +intermediate process mhm of conflict of + + + align:start position:0% +intermediate process mhm of conflict of +paradigms I want to say that it's not + + align:start position:0% +paradigms I want to say that it's not + + + align:start position:0% +paradigms I want to say that it's not +it's not + + align:start position:0% +it's not + + + align:start position:0% +it's not +an it's not a process that will take + + align:start position:0% +an it's not a process that will take + + + align:start position:0% +an it's not a process that will take +forever it's it's + + align:start position:0% +forever it's it's + + + align:start position:0% +forever it's it's +a it's an intermediate process to get + + align:start position:0% +a it's an intermediate process to get + + + align:start position:0% +a it's an intermediate process to get +somewhere after + + align:start position:0% +somewhere after + + + align:start position:0% +somewhere after +I don't know if it's the right word that + + align:start position:0% +I don't know if it's the right word that + + + align:start position:0% +I don't know if it's the right word that +mean the right + + align:start position:0% +mean the right + + + align:start position:0% +mean the right +word + + align:start position:0% +word + + + align:start position:0% +word +intermediate inter + + align:start position:0% +intermediate inter + + + align:start position:0% +intermediate inter +mediate it's a process that has it's a + + align:start position:0% +mediate it's a process that has it's a + + + align:start position:0% +mediate it's a process that has it's a +it's a stage of development exactly + + align:start position:0% +it's a stage of development exactly + + + align:start position:0% +it's a stage of development exactly +exactly okay it's a how do you say that + + align:start position:0% +exactly okay it's a how do you say that + + + align:start position:0% +exactly okay it's a how do you say that +is that a word for that immedate intered + + align:start position:0% +is that a word for that immedate intered + + + align:start position:0% +is that a word for that immedate intered +intermediate stage intermediate stage + + align:start position:0% +intermediate stage intermediate stage + + + align:start position:0% +intermediate stage intermediate stage +intermediate stage yes it + + align:start position:0% +intermediate stage yes it + + + align:start position:0% +intermediate stage yes it +is towards what a change in + + align:start position:0% + + + + align:start position:0% + +paradig + + align:start position:0% + + + + align:start position:0% + +okay in par okay um I wrote down + + align:start position:0% +okay in par okay um I wrote down + + + align:start position:0% +okay in par okay um I wrote down +demystifying + + align:start position:0% +demystifying + + + align:start position:0% +demystifying +demystifying reflective practice in a + + align:start position:0% +demystifying reflective practice in a + + + align:start position:0% +demystifying reflective practice in a +community Through facilitation can + + align:start position:0% +community Through facilitation can + + + align:start position:0% +community Through facilitation can +result in collective decision + + align:start position:0% +result in collective decision + + + align:start position:0% +result in collective decision +making should I say it's slower no okay + + align:start position:0% +making should I say it's slower no okay + + + align:start position:0% +making should I say it's slower no okay +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +mhm + + align:start position:0% +mhm + + + align:start position:0% +mhm +Community dis mystifying effective + + align:start position:0% +Community dis mystifying effective + + + align:start position:0% +Community dis mystifying effective +practice in communities in a in a + + align:start position:0% +practice in communities in a in a + + + align:start position:0% +practice in communities in a in a +community Through facilitation resulting + + align:start position:0% +community Through facilitation resulting + + + align:start position:0% +community Through facilitation resulting +in collective decision + + align:start position:0% + + + + align:start position:0% + +making okay you I'm not done okay please + + align:start position:0% +making okay you I'm not done okay please + + + align:start position:0% +making okay you I'm not done okay please +uh reflective practice can change the + + align:start position:0% +uh reflective practice can change the + + + align:start position:0% +uh reflective practice can change the +way we sorry I wait + + align:start position:0% + + + + align:start position:0% + +for um reflective practice can change + + align:start position:0% +for um reflective practice can change + + + align:start position:0% +for um reflective practice can change +the way we think feel and act as we + + align:start position:0% +the way we think feel and act as we + + + align:start position:0% +the way we think feel and act as we +evolve through our lives into higher + + align:start position:0% + + + + align:start position:0% + +beings respective + + align:start position:0% + + + + align:start position:0% + +practice change the way we think feel + + align:start position:0% +practice change the way we think feel + + + align:start position:0% +practice change the way we think feel +and act think feel and act as we evolve + + align:start position:0% +and act think feel and act as we evolve + + + align:start position:0% +and act think feel and act as we evolve +through our lives as we evolve + + align:start position:0% +through our lives as we evolve + + + align:start position:0% +through our lives as we evolve +all life into higher + + align:start position:0% + + + + align:start position:0% + +beings okay thank you Esra uh so all + + align:start position:0% +beings okay thank you Esra uh so all + + + align:start position:0% +beings okay thank you Esra uh so all +three of mine were actually sort of one + + align:start position:0% + + + + align:start position:0% + +long so basically I was thinking that + + align:start position:0% +long so basically I was thinking that + + + align:start position:0% +long so basically I was thinking that +reflective practice could enable um + + align:start position:0% +reflective practice could enable um + + + align:start position:0% +reflective practice could enable um +conception of new uh hybrid + + align:start position:0% +conception of new uh hybrid + + + align:start position:0% +conception of new uh hybrid +interdisiplinary + + align:start position:0% +interdisiplinary + + + align:start position:0% +interdisiplinary +teams which would then also enable those + + align:start position:0% +teams which would then also enable those + + + align:start position:0% +teams which would then also enable those +hybrid teams to improve their + + align:start position:0% +hybrid teams to improve their + + + align:start position:0% +hybrid teams to improve their +effectiveness as they work + + align:start position:0% +effectiveness as they work + + + align:start position:0% +effectiveness as they work +together which would then enable the + + align:start position:0% +together which would then enable the + + + align:start position:0% +together which would then enable the +development of new conceptual + + align:start position:0% +development of new conceptual + + + align:start position:0% +development of new conceptual +Innovations enabling Solutions of + + align:start position:0% +Innovations enabling Solutions of + + + align:start position:0% +Innovations enabling Solutions of +intractable problems problems that were + + align:start position:0% +intractable problems problems that were + + + align:start position:0% +intractable problems problems that were +previously intract okay work better + + align:start position:0% +previously intract okay work better + + + align:start position:0% +previously intract okay work better +together and what else uh so enable the + + align:start position:0% +together and what else uh so enable the + + + align:start position:0% +together and what else uh so enable the +teams to come to come together and then + + align:start position:0% +teams to come to come together and then + + + align:start position:0% +teams to come to come together and then +to work better together so the creation + + align:start position:0% +to work better together so the creation + + + align:start position:0% +to work better together so the creation +of + + align:start position:0% +of + + + align:start position:0% +of +team and then uh getting them to work + + align:start position:0% +team and then uh getting them to work + + + align:start position:0% +team and then uh getting them to work +better once they're actually together + + align:start position:0% +better once they're actually together + + + align:start position:0% +better once they're actually together +and + + align:start position:0% +and + + + align:start position:0% +and +then uh which would then enable the + + align:start position:0% +then uh which would then enable the + + + align:start position:0% +then uh which would then enable the +development of new conceptual + + align:start position:0% + + + + align:start position:0% + +Innovations okay thank + + align:start position:0% +Innovations okay thank + + + align:start position:0% +Innovations okay thank +you um I + + align:start position:0% + + + + align:start position:0% + +put okay + + align:start position:0% + + + + align:start position:0% + +I put um reflective practice can help + + align:start position:0% +I put um reflective practice can help + + + align:start position:0% +I put um reflective practice can help +build + + align:start position:0% +build + + + align:start position:0% +build +consensus in a complex society where an + + align:start position:0% +consensus in a complex society where an + + + align:start position:0% +consensus in a complex society where an +increasing number of Interest must be + + align:start position:0% + + + + align:start position:0% + +balanced where there's an increasing + + align:start position:0% +balanced where there's an increasing + + + align:start position:0% +balanced where there's an increasing +where an increasing number of Interest + + align:start position:0% + + + + align:start position:0% + +really well one of my couple of my + + align:start position:0% +really well one of my couple of my + + + align:start position:0% +really well one of my couple of my +thoughts are already up there so I'll + + align:start position:0% +thoughts are already up there so I'll + + + align:start position:0% +thoughts are already up there so I'll +play Devil's Advocate and say that the + + align:start position:0% +play Devil's Advocate and say that the + + + align:start position:0% +play Devil's Advocate and say that the +new environment with the massive amount + + align:start position:0% +new environment with the massive amount + + + align:start position:0% +new environment with the massive amount +of information and the ability to share + + align:start position:0% +of information and the ability to share + + + align:start position:0% +of information and the ability to share +it so fast will make reflective practice + + align:start position:0% +it so fast will make reflective practice + + + align:start position:0% +it so fast will make reflective practice +ever more difficult + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +yeah + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +okay we make effective practice even + + align:start position:0% +okay we make effective practice even + + + align:start position:0% +okay we make effective practice even +more difficult + + align:start position:0% + + + + align:start position:0% + +okay no + + align:start position:0% +okay no + + + align:start position:0% +okay no +way the increasing amounts of you know + + align:start position:0% +way the increasing amounts of you know + + + align:start position:0% +way the increasing amounts of you know +information + + align:start position:0% +information + + + align:start position:0% +information +and like groups + + align:start position:0% + + + + align:start position:0% + +blogging yeah to answer the question of + + align:start position:0% +blogging yeah to answer the question of + + + align:start position:0% +blogging yeah to answer the question of +what possibilities are opening for + + align:start position:0% +what possibilities are opening for + + + align:start position:0% +what possibilities are opening for +reflective practice I think I think that + + align:start position:0% +reflective practice I think I think that + + + align:start position:0% +reflective practice I think I think that +um the new discoveries are challenging + + align:start position:0% +um the new discoveries are challenging + + + align:start position:0% +um the new discoveries are challenging +assumptions mhm so that opens + + align:start position:0% +assumptions mhm so that opens + + + align:start position:0% +assumptions mhm so that opens +opportunities for reflective practice + + align:start position:0% +opportunities for reflective practice + + + align:start position:0% +opportunities for reflective practice +mhm + + align:start position:0% +mhm + + + align:start position:0% +mhm +okay + + align:start position:0% +okay + + + align:start position:0% +okay +okay yes + + align:start position:0% +okay yes + + + align:start position:0% +okay yes +okay let's wait just a second + + align:start position:0% +okay let's wait just a second + + + align:start position:0% +okay let's wait just a second +for to finish to + + align:start position:0% + + + + align:start position:0% + +WR + + align:start position:0% +WR + + + align:start position:0% +WR +scoll + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +yeah yes she can she has space there to + + align:start position:0% +yeah yes she can she has space there to + + + align:start position:0% +yeah yes she can she has space there to +reflection prac we can find a common + + align:start position:0% +reflection prac we can find a common + + + align:start position:0% +reflection prac we can find a common +solution for local communities and + + align:start position:0% +solution for local communities and + + + align:start position:0% +solution for local communities and +Global problems through theory and + + align:start position:0% + + + + align:start position:0% + +practice + + align:start position:0% +practice + + + align:start position:0% +practice +Comm + + align:start position:0% +Comm + + + align:start position:0% +Comm +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +solutions + + align:start position:0% +solutions + + + align:start position:0% +solutions +for local + + align:start position:0% +for local + + + align:start position:0% +for local +problems + + align:start position:0% +problems + + + align:start position:0% +problems +problems okay okay thank you very much + + align:start position:0% +problems okay okay thank you very much + + + align:start position:0% +problems okay okay thank you very much +okay so these are the ideas you can + + align:start position:0% +okay so these are the ideas you can + + + align:start position:0% +okay so these are the ideas you can +visualize for the future of effective + + align:start position:0% + + + + align:start position:0% + +practice + + align:start position:0% +practice + + + align:start position:0% +practice +see + + align:start position:0% +see + + + align:start position:0% +see +okay my on view about that is + + align:start position:0% +okay my on view about that is + + + align:start position:0% +okay my on view about that is +that in the next time I think that + + align:start position:0% +that in the next time I think that + + + align:start position:0% +that in the next time I think that +people will recreate reflective practice + + align:start position:0% +people will recreate reflective practice + + + align:start position:0% +people will recreate reflective practice +in a way for to do it much more + + align:start position:0% +in a way for to do it much more + + + align:start position:0% +in a way for to do it much more +practical okay and Powerful + + align:start position:0% +practical okay and Powerful + + + align:start position:0% +practical okay and Powerful +for solving this kind of problems like + + align:start position:0% +for solving this kind of problems like + + + align:start position:0% +for solving this kind of problems like +conceptual + + align:start position:0% +conceptual + + + align:start position:0% +conceptual +Innovation ER + + align:start position:0% +Innovation ER + + + align:start position:0% +Innovation ER +different ER perspectives of different + + align:start position:0% +different ER perspectives of different + + + align:start position:0% +different ER perspectives of different +groups things like that I think that + + align:start position:0% +groups things like that I think that + + + align:start position:0% +groups things like that I think that +reflective practice will + + align:start position:0% +reflective practice will + + + align:start position:0% +reflective practice will +be recreated in the next years \ No newline at end of file diff --git a/WwBaQCy4jfk.txt b/WwBaQCy4jfk.txt new file mode 100644 index 0000000000000000000000000000000000000000..939a79153cd0f100b45899bddaebc30acd9999f4 --- /dev/null +++ b/WwBaQCy4jfk.txt @@ -0,0 +1,3280 @@ +align:start position:0% + +hi welcome back to recitation in lecture + + align:start position:0% +hi welcome back to recitation in lecture + + + align:start position:0% +hi welcome back to recitation in lecture +you've been learning about the + + align:start position:0% +you've been learning about the + + + align:start position:0% +you've been learning about the +Divergence Theorem also known as gauss's + + align:start position:0% +Divergence Theorem also known as gauss's + + + align:start position:0% +Divergence Theorem also known as gauss's +theorem and flux and all that good stuff + + align:start position:0% +theorem and flux and all that good stuff + + + align:start position:0% +theorem and flux and all that good stuff +so I have a a nice exercise on it for + + align:start position:0% +so I have a a nice exercise on it for + + + align:start position:0% +so I have a a nice exercise on it for +you here um so what I want is I want you + + align:start position:0% +you here um so what I want is I want you + + + align:start position:0% +you here um so what I want is I want you +to take F I want it to be the field + + align:start position:0% +to take F I want it to be the field + + + align:start position:0% +to take F I want it to be the field +whose components are X over row cubed y + + align:start position:0% +whose components are X over row cubed y + + + align:start position:0% +whose components are X over row cubed y +overow row cubed and Z over row cubed so + + align:start position:0% +overow row cubed and Z over row cubed so + + + align:start position:0% +overow row cubed and Z over row cubed so +here row is your usual Row from + + align:start position:0% +here row is your usual Row from + + + align:start position:0% +here row is your usual Row from +spherical coordinates row is equal to + + align:start position:0% +spherical coordinates row is equal to + + + align:start position:0% +spherical coordinates row is equal to +the otk of x^2 plus y^ S Plus z^2 um and + + align:start position:0% +the otk of x^2 plus y^ S Plus z^2 um and + + + align:start position:0% +the otk of x^2 plus y^ S Plus z^2 um and +I want s to be the surface of the Box + + align:start position:0% +I want s to be the surface of the Box + + + align:start position:0% +I want s to be the surface of the Box +whose vertices are plus or- 2 plus or -2 + + align:start position:0% +whose vertices are plus or- 2 plus or -2 + + + align:start position:0% +whose vertices are plus or- 2 plus or -2 +Plus or min-2 um so it's a a cubical box + + align:start position:0% +Plus or min-2 um so it's a a cubical box + + + align:start position:0% +Plus or min-2 um so it's a a cubical box +um so what I'd like you to do is first + + align:start position:0% +um so what I'd like you to do is first + + + align:start position:0% +um so what I'd like you to do is first +in part A I'd like you to show that the + + align:start position:0% +in part A I'd like you to show that the + + + align:start position:0% +in part A I'd like you to show that the +Divergence of f is zero wherever the + + align:start position:0% +Divergence of f is zero wherever the + + + align:start position:0% +Divergence of f is zero wherever the +field f is defined um in Part B what I'd + + align:start position:0% +field f is defined um in Part B what I'd + + + align:start position:0% +field f is defined um in Part B what I'd +like you to think about is whether we + + align:start position:0% +like you to think about is whether we + + + align:start position:0% +like you to think about is whether we +can conclude from that that the the the + + align:start position:0% +can conclude from that that the the the + + + align:start position:0% +can conclude from that that the the the +flux through the surface of s is equal + + align:start position:0% +flux through the surface of s is equal + + + align:start position:0% +flux through the surface of s is equal +to zero all right and in part + + align:start position:0% +to zero all right and in part + + + align:start position:0% +to zero all right and in part +three or C um what I'd like you to do is + + align:start position:0% +three or C um what I'd like you to do is + + + align:start position:0% +three or C um what I'd like you to do is +to use the extended version of gauss's + + align:start position:0% +to use the extended version of gauss's + + + align:start position:0% +to use the extended version of gauss's +theorem or the extended version of the + + align:start position:0% +theorem or the extended version of the + + + align:start position:0% +theorem or the extended version of the +Divergence Theorem um in order to to + + align:start position:0% +Divergence Theorem um in order to to + + + align:start position:0% +Divergence Theorem um in order to to +actually compute the flux through S by + + align:start position:0% +actually compute the flux through S by + + + align:start position:0% +actually compute the flux through S by +Computing an integral so uh why why + + align:start position:0% +Computing an integral so uh why why + + + align:start position:0% +Computing an integral so uh why why +don't you pause the video for a couple + + align:start position:0% +don't you pause the video for a couple + + + align:start position:0% +don't you pause the video for a couple +of minutes come back we can uh work jeez + + align:start position:0% +of minutes come back we can uh work jeez + + + align:start position:0% +of minutes come back we can uh work jeez +pause the video for a couple minutes + + align:start position:0% +pause the video for a couple minutes + + + align:start position:0% +pause the video for a couple minutes +work out this problem come back and we + + align:start position:0% +work out this problem come back and we + + + align:start position:0% +work out this problem come back and we +can work it out + + align:start position:0% + + + + align:start position:0% + +together hopefully you had some luck + + align:start position:0% +together hopefully you had some luck + + + align:start position:0% +together hopefully you had some luck +with this problem let's get started part + + align:start position:0% +with this problem let's get started part + + + align:start position:0% +with this problem let's get started part +A asks you to compute the Divergence of + + align:start position:0% +A asks you to compute the Divergence of + + + align:start position:0% +A asks you to compute the Divergence of +f so in order to compute that well we're + + align:start position:0% +f so in order to compute that well we're + + + align:start position:0% +f so in order to compute that well we're +going to need to take the partial + + align:start position:0% +going to need to take the partial + + + align:start position:0% +going to need to take the partial +derivatives of the components of F and + + align:start position:0% +derivatives of the components of F and + + + align:start position:0% +derivatives of the components of F and +in order to do that at some point I'm + + align:start position:0% +in order to do that at some point I'm + + + align:start position:0% +in order to do that at some point I'm +going to need to take a partial + + align:start position:0% +going to need to take a partial + + + align:start position:0% +going to need to take a partial +derivative of row so let me first + + align:start position:0% +derivative of row so let me first + + + align:start position:0% +derivative of row so let me first +compute the partial derivatives of row + + align:start position:0% +compute the partial derivatives of row + + + align:start position:0% +compute the partial derivatives of row +and that'll save me a tiny bit of work + + align:start position:0% +and that'll save me a tiny bit of work + + + align:start position:0% +and that'll save me a tiny bit of work +later so row is equal to the < TK of x^2 + + align:start position:0% +later so row is equal to the < TK of x^2 + + + align:start position:0% +later so row is equal to the < TK of x^2 ++ y^ 2 plus z^ + + align:start position:0% ++ y^ 2 plus z^ + + + align:start position:0% ++ y^ 2 plus z^ + + align:start position:0% + + + align:start position:0% +so partial + + align:start position:0% +so partial + + + align:start position:0% +so partial +row partial X well you just apply your + + align:start position:0% +row partial X well you just apply your + + + align:start position:0% +row partial X well you just apply your +usual chain rule here and I guess we get + + align:start position:0% +usual chain rule here and I guess we get + + + align:start position:0% +usual chain rule here and I guess we get +a half but then we get a two that + + align:start position:0% +a half but then we get a two that + + + align:start position:0% +a half but then we get a two that +cancels it so I think this works out to + + align:start position:0% +cancels it so I think this works out to + + + align:start position:0% +cancels it so I think this works out to +x / the < TK of x^2 + y^2 + z^2 so + + align:start position:0% +x / the < TK of x^2 + y^2 + z^2 so + + + align:start position:0% +x / the < TK of x^2 + y^2 + z^2 so +that's x / row all right and we're I'm + + align:start position:0% +that's x / row all right and we're I'm + + + align:start position:0% +that's x / row all right and we're I'm +just going to keep row around here + + align:start position:0% +just going to keep row around here + + + align:start position:0% +just going to keep row around here +because it you know because otherwise I + + align:start position:0% +because it you know because otherwise I + + + align:start position:0% +because it you know because otherwise I +have to write out the square root of x s + + align:start position:0% +have to write out the square root of x s + + + align:start position:0% +have to write out the square root of x s +plus y squ plus z s over and over again + + align:start position:0% +plus y squ plus z s over and over again + + + align:start position:0% +plus y squ plus z s over and over again +and this is going to save me um some + + align:start position:0% +and this is going to save me um some + + + align:start position:0% +and this is going to save me um some +effort and would save you some effort um + + align:start position:0% +effort and would save you some effort um + + + align:start position:0% +effort and would save you some effort um +as well so okay so row this is row so + + align:start position:0% +as well so okay so row this is row so + + + align:start position:0% +as well so okay so row this is row so +this is D DX um so the component of + + align:start position:0% +this is D DX um so the component of + + + align:start position:0% +this is D DX um so the component of +F that we want to take the partial of so + + align:start position:0% +F that we want to take the partial of so + + + align:start position:0% +F that we want to take the partial of so +we want to take the X partial of the + + align:start position:0% +we want to take the X partial of the + + + align:start position:0% +we want to take the X partial of the +first component of f so that's the X + + align:start position:0% +first component of f so that's the X + + + align:start position:0% +first component of f so that's the X +partial of X over row + + align:start position:0% +partial of X over row + + + align:start position:0% +partial of X over row +cubed okay and you just apply your usual + + align:start position:0% +cubed okay and you just apply your usual + + + align:start position:0% +cubed okay and you just apply your usual +quotient rule so what do we get we get + + align:start position:0% +quotient rule so what do we get we get + + + align:start position:0% +quotient rule so what do we get we get +the derivative of the top so that's row + + align:start position:0% +the derivative of the top so that's row + + + align:start position:0% +the derivative of the top so that's row +cubed minus okay so the top is x times + + align:start position:0% +cubed minus okay so the top is x times + + + align:start position:0% +cubed minus okay so the top is x times +the derivative of the bottom is going to + + align:start position:0% +the derivative of the bottom is going to + + + align:start position:0% +the derivative of the bottom is going to +be 3 row 2ar * X over row so that's + + align:start position:0% +be 3 row 2ar * X over row so that's + + + align:start position:0% +be 3 row 2ar * X over row so that's +three so we have an X so it's + + align:start position:0% +three so we have an X so it's + + + align:start position:0% +three so we have an X so it's +3x^2 row / the bottom squar which is row + + align:start position:0% +3x^2 row / the bottom squar which is row + + + align:start position:0% +3x^2 row / the bottom squar which is row +to the 6 and I guess there's a common + + align:start position:0% +to the 6 and I guess there's a common + + + align:start position:0% +to the 6 and I guess there's a common +factor of row everywhere that we can + + align:start position:0% +factor of row everywhere that we can + + + align:start position:0% +factor of row everywhere that we can +cancel out so this is equal to Row 2 - 3 + + align:start position:0% +cancel out so this is equal to Row 2 - 3 + + + align:start position:0% +cancel out so this is equal to Row 2 - 3 +x^2 / row to the 5th okay so that's the + + align:start position:0% +x^2 / row to the 5th okay so that's the + + + align:start position:0% +x^2 / row to the 5th okay so that's the +partial the X partial derivative of the + + align:start position:0% +partial the X partial derivative of the + + + align:start position:0% +partial the X partial derivative of the +first component of f now we need the Y + + align:start position:0% +first component of f now we need the Y + + + align:start position:0% +first component of f now we need the Y +partial derivative of the second + + align:start position:0% +partial derivative of the second + + + align:start position:0% +partial derivative of the second +component of F and the Z partial + + align:start position:0% +component of F and the Z partial + + + align:start position:0% +component of F and the Z partial +derivative of the third component of f + + align:start position:0% +derivative of the third component of f + + + align:start position:0% +derivative of the third component of f +but if you go and look back at what the + + align:start position:0% +but if you go and look back at what the + + + align:start position:0% +but if you go and look back at what the +formula for f was you see that this is a + + align:start position:0% +formula for f was you see that this is a + + + align:start position:0% +formula for f was you see that this is a +very very symmetric formula so in order + + align:start position:0% +very very symmetric formula so in order + + + align:start position:0% +very very symmetric formula so in order +to get from the first component to the + + align:start position:0% +to get from the first component to the + + + align:start position:0% +to get from the first component to the +second component we just change X to Y + + align:start position:0% +second component we just change X to Y + + + align:start position:0% +second component we just change X to Y +and to get from the second component to + + align:start position:0% +and to get from the second component to + + + align:start position:0% +and to get from the second component to +the third we just change y to Z because + + align:start position:0% +the third we just change y to Z because + + + align:start position:0% +the third we just change y to Z because +of course row is treats X Y and Z the + + align:start position:0% +of course row is treats X Y and Z the + + + align:start position:0% +of course row is treats X Y and Z the +same um so what does that mean well that + + align:start position:0% +same um so what does that mean well that + + + align:start position:0% +same um so what does that mean well that +means that the partial derivatives are + + align:start position:0% +means that the partial derivatives are + + + align:start position:0% +means that the partial derivatives are +easy to compute having computed this x + + align:start position:0% +easy to compute having computed this x + + + align:start position:0% +easy to compute having computed this x +partial derivative we also get um that + + align:start position:0% +partial derivative we also get um that + + + align:start position:0% +partial derivative we also get um that +partial + + align:start position:0% + + + + align:start position:0% + +uh over partial y of the second + + align:start position:0% +uh over partial y of the second + + + align:start position:0% +uh over partial y of the second +component which is y over row cubed is + + align:start position:0% +component which is y over row cubed is + + + align:start position:0% +component which is y over row cubed is +equal to Row 2 - 3 y^ 2 over row 5th and + + align:start position:0% +equal to Row 2 - 3 y^ 2 over row 5th and + + + align:start position:0% +equal to Row 2 - 3 y^ 2 over row 5th and +the last one we get partial over partial + + align:start position:0% +the last one we get partial over partial + + + align:start position:0% +the last one we get partial over partial +Z of Z over row + + align:start position:0% +Z of Z over row + + + align:start position:0% +Z of Z over row +cubed is equal to Row 2 minus sorry I'm + + align:start position:0% +cubed is equal to Row 2 minus sorry I'm + + + align:start position:0% +cubed is equal to Row 2 minus sorry I'm +getting a little cramped here 3 z^ 2 + + align:start position:0% +getting a little cramped here 3 z^ 2 + + + align:start position:0% +getting a little cramped here 3 z^ 2 +over row to the + + align:start position:0% +over row to the + + + align:start position:0% +over row to the +5th and so adding these up we get + + align:start position:0% +5th and so adding these up we get + + + align:start position:0% +5th and so adding these up we get +that div f is equal to well it's just + + align:start position:0% +that div f is equal to well it's just + + + align:start position:0% +that div f is equal to well it's just +equal to the sum of those three things + + align:start position:0% +equal to the sum of those three things + + + align:start position:0% +equal to the sum of those three things +so that's let's see what we've got we've + + align:start position:0% +so that's let's see what we've got we've + + + align:start position:0% +so that's let's see what we've got we've +got a three so the denominators are all + + align:start position:0% +got a three so the denominators are all + + + align:start position:0% +got a three so the denominators are all +row to the 5th and we've got 3 Row 2 - + + align:start position:0% +row to the 5th and we've got 3 Row 2 - + + + align:start position:0% +row to the 5th and we've got 3 Row 2 - +3x^ 2 - 3 y^ 2 - 3 Z 2 so this is equal + + align:start position:0% +3x^ 2 - 3 y^ 2 - 3 Z 2 so this is equal + + + align:start position:0% +3x^ 2 - 3 y^ 2 - 3 Z 2 so this is equal +to 3 Row 2 - 3 x^ 2 - 3 y^ 2 - 3 z^2 all + + align:start position:0% +to 3 Row 2 - 3 x^ 2 - 3 y^ 2 - 3 z^2 all + + + align:start position:0% +to 3 Row 2 - 3 x^ 2 - 3 y^ 2 - 3 z^2 all +over row to the 5th but of course Row 2 + + align:start position:0% +over row to the 5th but of course Row 2 + + + align:start position:0% +over row to the 5th but of course Row 2 +is x^2 + y^2 + z^2 so this numerator is + + align:start position:0% +is x^2 + y^2 + z^2 so this numerator is + + + align:start position:0% +is x^2 + y^2 + z^2 so this numerator is +just zero so this is equal to + + align:start position:0% +just zero so this is equal to + + + align:start position:0% +just zero so this is equal to +zero okay which is what we thought it + + align:start position:0% +zero okay which is what we thought it + + + align:start position:0% +zero okay which is what we thought it +should be all right good so so that's + + align:start position:0% +should be all right good so so that's + + + align:start position:0% +should be all right good so so that's +part A we just computed the partial + + align:start position:0% +part A we just computed the partial + + + align:start position:0% +part A we just computed the partial +derivatives of F and then added them + + align:start position:0% +derivatives of F and then added them + + + align:start position:0% +derivatives of F and then added them +together to get the Divergence and we we + + align:start position:0% +together to get the Divergence and we we + + + align:start position:0% +together to get the Divergence and we we +found that in fact yes the Divergence + + align:start position:0% +found that in fact yes the Divergence + + + align:start position:0% +found that in fact yes the Divergence +was equal to zero great so that's part A + + align:start position:0% +was equal to zero great so that's part A + + + align:start position:0% +was equal to zero great so that's part A +so let's go look at what part B was Part + + align:start position:0% +so let's go look at what part B was Part + + + align:start position:0% +so let's go look at what part B was Part +B asked can we conclude that the flux + + align:start position:0% +B asked can we conclude that the flux + + + align:start position:0% +B asked can we conclude that the flux +through the surface s is zero all right + + align:start position:0% +through the surface s is zero all right + + + align:start position:0% +through the surface s is zero all right +now remember what the Divergence Theorem + + align:start position:0% +now remember what the Divergence Theorem + + + align:start position:0% +now remember what the Divergence Theorem +says the Divergence Theorem says that + + align:start position:0% +says the Divergence Theorem says that + + + align:start position:0% +says the Divergence Theorem says that +the flux through a surface of a field is + + align:start position:0% +the flux through a surface of a field is + + + align:start position:0% +the flux through a surface of a field is +equal to the triple integral of the + + align:start position:0% +equal to the triple integral of the + + + align:start position:0% +equal to the triple integral of the +Divergence of that field over the + + align:start position:0% +Divergence of that field over the + + + align:start position:0% +Divergence of that field over the +interior provided the field is defined + + align:start position:0% +interior provided the field is defined + + + align:start position:0% +interior provided the field is defined +and differentiable and nice or whatever + + align:start position:0% +and differentiable and nice or whatever + + + align:start position:0% +and differentiable and nice or whatever +everywhere + + align:start position:0% +everywhere + + + align:start position:0% +everywhere +inside okay but this field has a problem + + align:start position:0% +inside okay but this field has a problem + + + align:start position:0% +inside okay but this field has a problem +almost everywhere this field is nicely + + align:start position:0% +almost everywhere this field is nicely + + + align:start position:0% +almost everywhere this field is nicely +behaved but at zero we have a real + + align:start position:0% +behaved but at zero we have a real + + + align:start position:0% +behaved but at zero we have a real +problem we're dividing by zero right so + + align:start position:0% +problem we're dividing by zero right so + + + align:start position:0% +problem we're dividing by zero right so +this field is not defined at zero so + + align:start position:0% +this field is not defined at zero so + + + align:start position:0% +this field is not defined at zero so +there's a single point in the middle of + + align:start position:0% +there's a single point in the middle of + + + align:start position:0% +there's a single point in the middle of +this Cube where this where this field + + align:start position:0% +this Cube where this where this field + + + align:start position:0% +this Cube where this where this field +behaves badly and that means we can't + + align:start position:0% +behaves badly and that means we can't + + + align:start position:0% +behaves badly and that means we can't +apply the Divergence Theorem inside this + + align:start position:0% +apply the Divergence Theorem inside this + + + align:start position:0% +apply the Divergence Theorem inside this +Cube so since we can't apply the + + align:start position:0% +Cube so since we can't apply the + + + align:start position:0% +Cube so since we can't apply the +Divergence Theorem we aren't allowed to + + align:start position:0% +Divergence Theorem we aren't allowed to + + + align:start position:0% +Divergence Theorem we aren't allowed to +conclude immediately + + align:start position:0% +conclude immediately + + + align:start position:0% +conclude immediately +that that the diver that the flux + + align:start position:0% +that that the diver that the flux + + + align:start position:0% +that that the diver that the flux +through this surface is zero okay so the + + align:start position:0% +through this surface is zero okay so the + + + align:start position:0% +through this surface is zero okay so the +answer is no we can't conclude that the + + align:start position:0% +answer is no we can't conclude that the + + + align:start position:0% +answer is no we can't conclude that the +flux through S is zero because one of + + align:start position:0% +flux through S is zero because one of + + + align:start position:0% +flux through S is zero because one of +the hypotheses of the Divergence Theorem + + align:start position:0% +the hypotheses of the Divergence Theorem + + + align:start position:0% +the hypotheses of the Divergence Theorem +isn't satisfied namely the field isn't + + align:start position:0% +isn't satisfied namely the field isn't + + + align:start position:0% +isn't satisfied namely the field isn't +defined everywhere inside the region or + + align:start position:0% +defined everywhere inside the region or + + + align:start position:0% +defined everywhere inside the region or +inside the surface um okay so so the + + align:start position:0% +inside the surface um okay so so the + + + align:start position:0% +inside the surface um okay so so the +answer to + + align:start position:0% + + + + align:start position:0% + +B is no okay I'm just going to write + + align:start position:0% +B is no okay I'm just going to write + + + align:start position:0% +B is no okay I'm just going to write +that but it's no because the hypotheses + + align:start position:0% +that but it's no because the hypotheses + + + align:start position:0% +that but it's no because the hypotheses +aren't satisfied ified okay so now let's + + align:start position:0% +aren't satisfied ified okay so now let's + + + align:start position:0% +aren't satisfied ified okay so now let's +look at Pro Part c um so part C suggests + + align:start position:0% +look at Pro Part c um so part C suggests + + + align:start position:0% +look at Pro Part c um so part C suggests +okay so we couldn't we can't conclude + + align:start position:0% +okay so we couldn't we can't conclude + + + align:start position:0% +okay so we couldn't we can't conclude +that that the flux is zero so okay so so + + align:start position:0% +that that the flux is zero so okay so so + + + align:start position:0% +that that the flux is zero so okay so so +we still want to know what the flux is + + align:start position:0% +we still want to know what the flux is + + + align:start position:0% +we still want to know what the flux is +right then that's still an interesting + + align:start position:0% +right then that's still an interesting + + + align:start position:0% +right then that's still an interesting +question so so part C suggests maybe you + + align:start position:0% +question so so part C suggests maybe you + + + align:start position:0% +question so so part C suggests maybe you +can still use the Divergence Theorem + + align:start position:0% +can still use the Divergence Theorem + + + align:start position:0% +can still use the Divergence Theorem +well now it's we're calling it Gus's + + align:start position:0% +well now it's we're calling it Gus's + + + align:start position:0% +well now it's we're calling it Gus's +theorem extended gauss's theorem to + + align:start position:0% +theorem extended gauss's theorem to + + + align:start position:0% +theorem extended gauss's theorem to +compute what this flux is so let's let's + + align:start position:0% +compute what this flux is so let's let's + + + align:start position:0% +compute what this flux is so let's let's +think about how we could do that so + + align:start position:0% +think about how we could do that so + + + align:start position:0% +think about how we could do that so +remember what extended Gus's theorem + + align:start position:0% +remember what extended Gus's theorem + + + align:start position:0% +remember what extended Gus's theorem +says or extended Divergence Theorem it's + + align:start position:0% +says or extended Divergence Theorem it's + + + align:start position:0% +says or extended Divergence Theorem it's +I'm I'm just going to I'm going to try + + align:start position:0% +I'm I'm just going to I'm going to try + + + align:start position:0% +I'm I'm just going to I'm going to try +and just say gauss's theorem from now on + + align:start position:0% +and just say gauss's theorem from now on + + + align:start position:0% +and just say gauss's theorem from now on +so I stop having to say both but I mean + + align:start position:0% +so I stop having to say both but I mean + + + align:start position:0% +so I stop having to say both but I mean +both I mean they're the same theorem + + align:start position:0% +both I mean they're the same theorem + + + align:start position:0% +both I mean they're the same theorem +right okay so so extended Gus's theorem + + align:start position:0% +right okay so so extended Gus's theorem + + + align:start position:0% +right okay so so extended Gus's theorem +what that says so so Gus's theorem says + + align:start position:0% +what that says so so Gus's theorem says + + + align:start position:0% +what that says so so Gus's theorem says +when you have a when you have a surface + + align:start position:0% +when you have a when you have a surface + + + align:start position:0% +when you have a when you have a surface +bounding a region the flux through the + + align:start position:0% +bounding a region the flux through the + + + align:start position:0% +bounding a region the flux through the +surface is equal to the triple integral + + align:start position:0% +surface is equal to the triple integral + + + align:start position:0% +surface is equal to the triple integral +of Divergence over the region provided + + align:start position:0% +of Divergence over the region provided + + + align:start position:0% +of Divergence over the region provided +everything is well defined and nice um + + align:start position:0% +everything is well defined and nice um + + + align:start position:0% +everything is well defined and nice um +Extended gauss's theorem says this is + + align:start position:0% +Extended gauss's theorem says this is + + + align:start position:0% +Extended gauss's theorem says this is +still true if your if your region has + + align:start position:0% +still true if your if your region has + + + align:start position:0% +still true if your if your region has +more than one boundary so for example if + + align:start position:0% +more than one boundary so for example if + + + align:start position:0% +more than one boundary so for example if +your region is is a is a hollow + + align:start position:0% +your region is is a is a hollow + + + align:start position:0% +your region is is a is a hollow +something so if it you know it's a + + align:start position:0% +something so if it you know it's a + + + align:start position:0% +something so if it you know it's a +spherical shell that has an outside + + align:start position:0% +spherical shell that has an outside + + + align:start position:0% +spherical shell that has an outside +sphere and an inside sphere then then + + align:start position:0% +sphere and an inside sphere then then + + + align:start position:0% +sphere and an inside sphere then then +extended gauss's theorem says okay so + + align:start position:0% +extended gauss's theorem says okay so + + + align:start position:0% +extended gauss's theorem says okay so +you do the same thing you take the + + align:start position:0% +you do the same thing you take the + + + align:start position:0% +you do the same thing you take the +triple integral of the Divergence over + + align:start position:0% +triple integral of the Divergence over + + + align:start position:0% +triple integral of the Divergence over +the solid region and then you take the + + align:start position:0% +the solid region and then you take the + + + align:start position:0% +the solid region and then you take the +flux but you add up the flux over all of + + align:start position:0% +flux but you add up the flux over all of + + + align:start position:0% +flux but you add up the flux over all of +the boundary pieces so you add up the + + align:start position:0% +the boundary pieces so you add up the + + + align:start position:0% +the boundary pieces so you add up the +flux over the the outside boundary + + align:start position:0% +flux over the the outside boundary + + + align:start position:0% +flux over the the outside boundary +surface and also if there is one through + + align:start position:0% +surface and also if there is one through + + + align:start position:0% +surface and also if there is one through +any other boundary surfaces okay so + + align:start position:0% +any other boundary surfaces okay so + + + align:start position:0% +any other boundary surfaces okay so +that's and and those two things are + + align:start position:0% +that's and and those two things are + + + align:start position:0% +that's and and those two things are +equal the so the flux the total flux + + align:start position:0% +equal the so the flux the total flux + + + align:start position:0% +equal the so the flux the total flux +through all of the boundary surfaces is + + align:start position:0% +through all of the boundary surfaces is + + + align:start position:0% +through all of the boundary surfaces is +equal to the integral of Divergence over + + align:start position:0% +equal to the integral of Divergence over + + + align:start position:0% +equal to the integral of Divergence over +the whole region bounded by those + + align:start position:0% +the whole region bounded by those + + + align:start position:0% +the whole region bounded by those +surfaces all right so how are we going + + align:start position:0% +surfaces all right so how are we going + + + align:start position:0% +surfaces all right so how are we going +to use this so we're trying to compute + + align:start position:0% +to use this so we're trying to compute + + + align:start position:0% +to use this so we're trying to compute +the the surface the integral of we're + + align:start position:0% +the the surface the integral of we're + + + align:start position:0% +the the surface the integral of we're +trying to compute the flux through a + + align:start position:0% +trying to compute the flux through a + + + align:start position:0% +trying to compute the flux through a +Surface by + + align:start position:0% +Surface by + + + align:start position:0% +Surface by +okay but we don't want to compute a + + align:start position:0% +okay but we don't want to compute a + + + align:start position:0% +okay but we don't want to compute a +double integral if we could if we can + + align:start position:0% +double integral if we could if we can + + + align:start position:0% +double integral if we could if we can +avoid it we don't want to compute the + + align:start position:0% +avoid it we don't want to compute the + + + align:start position:0% +avoid it we don't want to compute the +surface integral um so what we'd like to + + align:start position:0% +surface integral um so what we'd like to + + + align:start position:0% +surface integral um so what we'd like to +do is we'd like to find a convenient + + align:start position:0% +do is we'd like to find a convenient + + + align:start position:0% +do is we'd like to find a convenient +region over which to compute this this + + align:start position:0% +region over which to compute this this + + + align:start position:0% +region over which to compute this this +uh this integral to put us in a + + align:start position:0% +uh this integral to put us in a + + + align:start position:0% +uh this integral to put us in a +situation where we can apply extended + + align:start position:0% +situation where we can apply extended + + + align:start position:0% +situation where we can apply extended +gases theorem so we can't use just the + + align:start position:0% +gases theorem so we can't use just the + + + align:start position:0% +gases theorem so we can't use just the +inside of the cube so we want some other + + align:start position:0% +inside of the cube so we want some other + + + align:start position:0% +inside of the cube so we want some other +region so what we're going to do is + + align:start position:0% +region so what we're going to do is + + + align:start position:0% +region so what we're going to do is +we're going to walk over here and we're + + align:start position:0% +we're going to walk over here and we're + + + align:start position:0% +we're going to walk over here and we're +going to do one well I mean there are + + align:start position:0% +going to do one well I mean there are + + + align:start position:0% +going to do one well I mean there are +many possible things you could do but + + align:start position:0% +many possible things you could do but + + + align:start position:0% +many possible things you could do but +this is a nice one all right one thing + + align:start position:0% +this is a nice one all right one thing + + + align:start position:0% +this is a nice one all right one thing +you could do is you could take a big + + align:start position:0% +you could do is you could take a big + + + align:start position:0% +you could do is you could take a big +sphere take a big sphere so we've got + + align:start position:0% +sphere take a big sphere so we've got + + + align:start position:0% +sphere take a big sphere so we've got +our Cube here these you know this is the + + align:start position:0% +our Cube here these you know this is the + + + align:start position:0% +our Cube here these you know this is the +point 222 and this is the point 22 minus + + align:start position:0% +point 222 and this is the point 22 minus + + + align:start position:0% +point 222 and this is the point 22 minus +2 and so on um so we've taken a big + + align:start position:0% +2 and so on um so we've taken a big + + + align:start position:0% +2 and so on um so we've taken a big +sphere of radius R for some Big R um + + align:start position:0% +sphere of radius R for some Big R um + + + align:start position:0% +sphere of radius R for some Big R um +that contains this this uh our surface s + + align:start position:0% +that contains this this uh our surface s + + + align:start position:0% +that contains this this uh our surface s +that we're interested in that completely + + align:start position:0% +that we're interested in that completely + + + align:start position:0% +that we're interested in that completely +contains the cube okay so so why have we + + align:start position:0% +contains the cube okay so so why have we + + + align:start position:0% +contains the cube okay so so why have we +done that well extended gauss's theorem + + align:start position:0% + + + + align:start position:0% + +says okay so what does extended Gus's + + align:start position:0% +says okay so what does extended Gus's + + + align:start position:0% +says okay so what does extended Gus's +theorem say for the region between the + + align:start position:0% +theorem say for the region between the + + + align:start position:0% +theorem say for the region between the +sphere and this Cube all right so so our + + align:start position:0% +sphere and this Cube all right so so our + + + align:start position:0% +sphere and this Cube all right so so our +our cube is named s let's call our + + align:start position:0% +our cube is named s let's call our + + + align:start position:0% +our cube is named s let's call our +sphere + + align:start position:0% +sphere + + + align:start position:0% +sphere +S2 because why not um okay and let's + + align:start position:0% +S2 because why not um okay and let's + + + align:start position:0% +S2 because why not um okay and let's +call the solid region between them + + align:start position:0% + + + + align:start position:0% + +between the + + align:start position:0% +between the + + + align:start position:0% +between the +cube and sphere well we you know we just + + align:start position:0% +cube and sphere well we you know we just + + + align:start position:0% +cube and sphere well we you know we just +just for convenience let's give it a + + align:start position:0% +just for convenience let's give it a + + + align:start position:0% +just for convenience let's give it a +name so I don't know we often call solid + + align:start position:0% +name so I don't know we often call solid + + + align:start position:0% +name so I don't know we often call solid +regions D so let's call it D so that's + + align:start position:0% +regions D so let's call it D so that's + + + align:start position:0% +regions D so let's call it D so that's +this it's this spherical region but it + + align:start position:0% +this it's this spherical region but it + + + align:start position:0% +this it's this spherical region but it +has a cubical hole in the middle of it + + align:start position:0% +has a cubical hole in the middle of it + + + align:start position:0% +has a cubical hole in the middle of it +okay so what does extended gauss's + + align:start position:0% +okay so what does extended gauss's + + + align:start position:0% +okay so what does extended gauss's +theorem say so extended Gus's theorem + + align:start position:0% +theorem say so extended Gus's theorem + + + align:start position:0% +theorem say so extended Gus's theorem +says that the tripal triple + + align:start position:0% +says that the tripal triple + + + align:start position:0% +says that the tripal triple +integral over D of the Divergence of + + align:start position:0% +integral over D of the Divergence of + + + align:start position:0% +integral over D of the Divergence of +f + + align:start position:0% +f + + + align:start position:0% +f +DV is equal to it's equal to okay the + + align:start position:0% +DV is equal to it's equal to okay the + + + align:start position:0% +DV is equal to it's equal to okay the +sum of the fluxes through each of the + + align:start position:0% +sum of the fluxes through each of the + + + align:start position:0% +sum of the fluxes through each of the +surfaces but we for this we want the + + align:start position:0% +surfaces but we for this we want the + + + align:start position:0% +surfaces but we for this we want the +flux out of the solid region so what + + align:start position:0% +flux out of the solid region so what + + + align:start position:0% +flux out of the solid region so what +that means is so for the sphere the flux + + align:start position:0% +that means is so for the sphere the flux + + + align:start position:0% +that means is so for the sphere the flux +out of the inside of of the sphere is + + align:start position:0% +out of the inside of of the sphere is + + + align:start position:0% +out of the inside of of the sphere is +the flux out of the sphere so + + align:start position:0% +the flux out of the sphere so + + + align:start position:0% +the flux out of the sphere so +that's integral over + + align:start position:0% +that's integral over + + + align:start position:0% +that's integral over +S2 of + + align:start position:0% +S2 of + + + align:start position:0% +S2 of +f do + + align:start position:0% +f do + + + align:start position:0% +f do +n d surface area but for the cube the + + align:start position:0% +n d surface area but for the cube the + + + align:start position:0% +n d surface area but for the cube the +flux out of this region is the flux into + + align:start position:0% +flux out of this region is the flux into + + + align:start position:0% +flux out of this region is the flux into +the + + align:start position:0% +the + + + align:start position:0% +the +cube right you're out here you're living + + align:start position:0% +cube right you're out here you're living + + + align:start position:0% +cube right you're out here you're living +in a region outside the cube so when you + + align:start position:0% +in a region outside the cube so when you + + + align:start position:0% +in a region outside the cube so when you +leave that region you're going into the + + align:start position:0% +leave that region you're going into the + + + align:start position:0% +leave that region you're going into the +cube so this is the negative of the flux + + align:start position:0% +cube so this is the negative of the flux + + + align:start position:0% +cube so this is the negative of the flux +that we really want so this is + + align:start position:0% + + + + align:start position:0% + +minus the flux through the cube of + + align:start position:0% + + + + align:start position:0% + +FN with respect to surface area so + + align:start position:0% +FN with respect to surface area so + + + align:start position:0% +FN with respect to surface area so +remember the signs here are different + + align:start position:0% +remember the signs here are different + + + align:start position:0% +remember the signs here are different +because what I'm take I'm taking this + + align:start position:0% +because what I'm take I'm taking this + + + align:start position:0% +because what I'm take I'm taking this +normal to be the outward pointing normal + + align:start position:0% +normal to be the outward pointing normal + + + align:start position:0% +normal to be the outward pointing normal +to both surfaces the normal that points + + align:start position:0% +to both surfaces the normal that points + + + align:start position:0% +to both surfaces the normal that points +away from the origin but the normal + + align:start position:0% +away from the origin but the normal + + + align:start position:0% +away from the origin but the normal +pointing away from the + + align:start position:0% +pointing away from the + + + align:start position:0% +pointing away from the +origin at on the cube is the normal that + + align:start position:0% +origin at on the cube is the normal that + + + align:start position:0% +origin at on the cube is the normal that +points into the solid region instead of + + align:start position:0% +points into the solid region instead of + + + align:start position:0% +points into the solid region instead of +the normal that points out of the solid + + align:start position:0% +the normal that points out of the solid + + + align:start position:0% +the normal that points out of the solid +region so that's why this minus sign is + + align:start position:0% +region so that's why this minus sign is + + + align:start position:0% +region so that's why this minus sign is +here okay all right so what does this + + align:start position:0% +here okay all right so what does this + + + align:start position:0% +here okay all right so what does this +mean well we we've already computed in + + align:start position:0% +mean well we we've already computed in + + + align:start position:0% +mean well we we've already computed in +part A that the diver so first of all f + + align:start position:0% +part A that the diver so first of all f + + + align:start position:0% +part A that the diver so first of all f +is well defined everywhere in this + + align:start position:0% +is well defined everywhere in this + + + align:start position:0% +is well defined everywhere in this +region D the only place F was badly + + align:start position:0% +region D the only place F was badly + + + align:start position:0% +region D the only place F was badly +behaved was the origin and this region + + align:start position:0% +behaved was the origin and this region + + + align:start position:0% +behaved was the origin and this region +doesn't contain it which is why this + + align:start position:0% +doesn't contain it which is why this + + + align:start position:0% +doesn't contain it which is why this +trick works so we already computed that + + align:start position:0% +trick works so we already computed that + + + align:start position:0% +trick works so we already computed that +the Divergence of f is zero everywhere + + align:start position:0% +the Divergence of f is zero everywhere + + + align:start position:0% +the Divergence of f is zero everywhere +it's defined so it's zero on all of D + + align:start position:0% +it's defined so it's zero on all of D + + + align:start position:0% +it's defined so it's zero on all of D +and so this triple integral is just zero + + align:start position:0% +and so this triple integral is just zero + + + align:start position:0% +and so this triple integral is just zero +so if this triple integral is zero that + + align:start position:0% +so if this triple integral is zero that + + + align:start position:0% +so if this triple integral is zero that +means we can just add um this other or + + align:start position:0% +means we can just add um this other or + + + align:start position:0% +means we can just add um this other or +the thing that we're interested in to + + align:start position:0% +the thing that we're interested in to + + + align:start position:0% +the thing that we're interested in to +both sides and we get + + align:start position:0% + + + + align:start position:0% + +that the surface integral over the cube + + align:start position:0% +that the surface integral over the cube + + + align:start position:0% +that the surface integral over the cube +of f.n with respect to surface area is + + align:start position:0% +of f.n with respect to surface area is + + + align:start position:0% +of f.n with respect to surface area is +equal to the surface integral over the + + align:start position:0% +equal to the surface integral over the + + + align:start position:0% +equal to the surface integral over the +sphere of + + align:start position:0% +sphere of + + + align:start position:0% +sphere of +f.n with respect to surface area okay so + + align:start position:0% +f.n with respect to surface area okay so + + + align:start position:0% +f.n with respect to surface area okay so +all right so we've we've + + align:start position:0% +all right so we've we've + + + align:start position:0% +all right so we've we've +converted this uh our original integral + + align:start position:0% +converted this uh our original integral + + + align:start position:0% +converted this uh our original integral +our flux integral that we're interested + + align:start position:0% +our flux integral that we're interested + + + align:start position:0% +our flux integral that we're interested +in and we've found that it's equal to + + align:start position:0% +in and we've found that it's equal to + + + align:start position:0% +in and we've found that it's equal to +this separate uh flux integral over a + + align:start position:0% +this separate uh flux integral over a + + + align:start position:0% +this separate uh flux integral over a +different surface this time over a big + + align:start position:0% +different surface this time over a big + + + align:start position:0% +different surface this time over a big +sphere okay so that's that's nice um why + + align:start position:0% +sphere okay so that's that's nice um why + + + align:start position:0% +sphere okay so that's that's nice um why +do we want to do that well we want to do + + align:start position:0% +do we want to do that well we want to do + + + align:start position:0% +do we want to do that well we want to do +that because f is a really nicely + + align:start position:0% +that because f is a really nicely + + + align:start position:0% +that because f is a really nicely +behaved field with respect to a sphere f + + align:start position:0% +behaved field with respect to a sphere f + + + align:start position:0% +behaved field with respect to a sphere f +is a radial field so F do + + align:start position:0% +is a radial field so F do + + + align:start position:0% +is a radial field so F do +n is really easy to understand + + align:start position:0% +n is really easy to understand + + + align:start position:0% +n is really easy to understand +FN is just well N is a unit normal and F + + align:start position:0% +FN is just well N is a unit normal and F + + + align:start position:0% +FN is just well N is a unit normal and F +is a radial field so on a sphere the the + + align:start position:0% +is a radial field so on a sphere the the + + + align:start position:0% +is a radial field so on a sphere the the +normal is radial right it it's it's + + align:start position:0% +normal is radial right it it's it's + + + align:start position:0% +normal is radial right it it's it's +parallel to the position vector and F is + + align:start position:0% +parallel to the position vector and F is + + + align:start position:0% +parallel to the position vector and F is +radial so they're both pointing in + + align:start position:0% +radial so they're both pointing in + + + align:start position:0% +radial so they're both pointing in +exactly the same direction so when you + + align:start position:0% +exactly the same direction so when you + + + align:start position:0% +exactly the same direction so when you +take that dot product n is the unit + + align:start position:0% +take that dot product n is the unit + + + align:start position:0% +take that dot product n is the unit +Vector in the same direction as F so + + align:start position:0% +Vector in the same direction as F so + + + align:start position:0% +Vector in the same direction as F so +when you dot that with f you just get + + align:start position:0% +when you dot that with f you just get + + + align:start position:0% +when you dot that with f you just get +the length of f okay so so what does + + align:start position:0% +the length of f okay so so what does + + + align:start position:0% +the length of f okay so so what does +that mean that means over + + align:start position:0% +that mean that means over + + + align:start position:0% +that mean that means over +here this integrand is really easy to + + align:start position:0% +here this integrand is really easy to + + + align:start position:0% +here this integrand is really easy to +understand okay this + + align:start position:0% +understand okay this + + + align:start position:0% +understand okay this +integrand f.n on the sphere is just + + align:start position:0% +integrand f.n on the sphere is just + + + align:start position:0% +integrand f.n on the sphere is just +equal to the + + align:start position:0% +equal to the + + + align:start position:0% +equal to the +length of the vector F now what is the + + align:start position:0% +length of the vector F now what is the + + + align:start position:0% +length of the vector F now what is the +length of the vector F well we know what + + align:start position:0% +length of the vector F well we know what + + + align:start position:0% +length of the vector F well we know what +f is it's X over row cubed I hat plus y + + align:start position:0% +f is it's X over row cubed I hat plus y + + + align:start position:0% +f is it's X over row cubed I hat plus y +over row cubed J hat plus Z over row + + align:start position:0% +over row cubed J hat plus Z over row + + + align:start position:0% +over row cubed J hat plus Z over row +cubed K hat so okay so you compute the + + align:start position:0% +cubed K hat so okay so you compute the + + + align:start position:0% +cubed K hat so okay so you compute the +length of that vector and what do you + + align:start position:0% +length of that vector and what do you + + + align:start position:0% +length of that vector and what do you +get well it's exactly 1 over row squared + + align:start position:0% +get well it's exactly 1 over row squared + + + align:start position:0% +get well it's exactly 1 over row squared +okay and but we said that this is a + + align:start position:0% +okay and but we said that this is a + + + align:start position:0% +okay and but we said that this is a +sphere I guess I didn't write it down so + + align:start position:0% +sphere I guess I didn't write it down so + + + align:start position:0% +sphere I guess I didn't write it down so +this is a sphere let me write it down + + align:start position:0% +this is a sphere let me write it down + + + align:start position:0% +this is a sphere let me write it down +right here this is a sphere whose radius + + align:start position:0% +right here this is a sphere whose radius + + + align:start position:0% +right here this is a sphere whose radius +is Big R it doesn't really matter very + + align:start position:0% +is Big R it doesn't really matter very + + + align:start position:0% +is Big R it doesn't really matter very +much what what R we choose we just want + + align:start position:0% +much what what R we choose we just want + + + align:start position:0% +much what what R we choose we just want +it to be big enough so that it contains + + align:start position:0% +it to be big enough so that it contains + + + align:start position:0% +it to be big enough so that it contains +the whole Cube if you said this is a + + align:start position:0% +the whole Cube if you said this is a + + + align:start position:0% +the whole Cube if you said this is a +sphere of radius 10 that would + + align:start position:0% +sphere of radius 10 that would + + + align:start position:0% +sphere of radius 10 that would +completely do the trick that would be + + align:start position:0% +completely do the trick that would be + + + align:start position:0% +completely do the trick that would be +totally fine + + align:start position:0% +totally fine + + + align:start position:0% +totally fine +okay so the radius of the sphere is Big + + align:start position:0% +okay so the radius of the sphere is Big + + + align:start position:0% +okay so the radius of the sphere is Big +R so the length of the field we said + + align:start position:0% +R so the length of the field we said + + + align:start position:0% +R so the length of the field we said +back over here is 1 + + align:start position:0% +back over here is 1 + + + align:start position:0% +back over here is 1 +over R 2 the the length of the vector + + align:start position:0% +over R 2 the the length of the vector + + + align:start position:0% +over R 2 the the length of the vector +F so this integral this this flux + + align:start position:0% +F so this integral this this flux + + + align:start position:0% +F so this integral this this flux +integral then is the integral over the + + align:start position:0% +integral then is the integral over the + + + align:start position:0% +integral then is the integral over the +sphere S2 of a + + align:start position:0% + + + + align:start position:0% + +constant so it's the integral over the + + align:start position:0% +constant so it's the integral over the + + + align:start position:0% +constant so it's the integral over the +sphere of 1/ R 2 DS + + align:start position:0% +sphere of 1/ R 2 DS + + + align:start position:0% +sphere of 1/ R 2 DS +but when you integrate a constant over a + + align:start position:0% +but when you integrate a constant over a + + + align:start position:0% +but when you integrate a constant over a +surface what you get is just that + + align:start position:0% +surface what you get is just that + + + align:start position:0% +surface what you get is just that +constant times the surface area well + + align:start position:0% +constant times the surface area well + + + align:start position:0% +constant times the surface area well +what's the surface area this is a sphere + + align:start position:0% +what's the surface area this is a sphere + + + align:start position:0% +what's the surface area this is a sphere +it's easy to understand its surface area + + align:start position:0% +it's easy to understand its surface area + + + align:start position:0% +it's easy to understand its surface area +its surface area is + + align:start position:0% +its surface area is + + + align:start position:0% +its surface area is +4 piir 2 right so this is equal to the + + align:start position:0% +4 piir 2 right so this is equal to the + + + align:start position:0% +4 piir 2 right so this is equal to the +surface area so that's 4 pi r 2times + + align:start position:0% +surface area so that's 4 pi r 2times + + + align:start position:0% +surface area so that's 4 pi r 2times +whatever that constant was so the + + align:start position:0% +whatever that constant was so the + + + align:start position:0% +whatever that constant was so the +constant was 1 / R 2 and so the r squs + + align:start position:0% +constant was 1 / R 2 and so the r squs + + + align:start position:0% +constant was 1 / R 2 and so the r squs +cancel right this is why it didn't + + align:start position:0% +cancel right this is why it didn't + + + align:start position:0% +cancel right this is why it didn't +matter what R we chose because it's just + + align:start position:0% +matter what R we chose because it's just + + + align:start position:0% +matter what R we chose because it's just +going to cancel at the end + + align:start position:0% + + + + align:start position:0% + +anyhow okay so those cancel and we're + + align:start position:0% +anyhow okay so those cancel and we're + + + align:start position:0% +anyhow okay so those cancel and we're +left with 4 Pi so let's let's just + + align:start position:0% +left with 4 Pi so let's let's just + + + align:start position:0% +left with 4 Pi so let's let's just +quickly recap what we did in this part + + align:start position:0% +quickly recap what we did in this part + + + align:start position:0% +quickly recap what we did in this part +C we're looking to compute the flux over + + align:start position:0% +C we're looking to compute the flux over + + + align:start position:0% +C we're looking to compute the flux over +the cube but it's a kind of unpleasant + + align:start position:0% +the cube but it's a kind of unpleasant + + + align:start position:0% +the cube but it's a kind of unpleasant +integral we'd have to compute to to + + align:start position:0% +integral we'd have to compute to to + + + align:start position:0% +integral we'd have to compute to to +total up the fluxes over these various + + align:start position:0% +total up the fluxes over these various + + + align:start position:0% +total up the fluxes over these various +different faces and so on so instead we + + align:start position:0% +different faces and so on so instead we + + + align:start position:0% +different faces and so on so instead we +had this clever idea that will apply the + + align:start position:0% +had this clever idea that will apply the + + + align:start position:0% +had this clever idea that will apply the +Divergence Theorem to replace the cube + + align:start position:0% +Divergence Theorem to replace the cube + + + align:start position:0% +Divergence Theorem to replace the cube +with a more congenial surface so the + + align:start position:0% +with a more congenial surface so the + + + align:start position:0% +with a more congenial surface so the +surface we choose because this is a nice + + align:start position:0% +surface we choose because this is a nice + + + align:start position:0% +surface we choose because this is a nice +radial Vector fi field that's our main + + align:start position:0% +radial Vector fi field that's our main + + + align:start position:0% +radial Vector fi field that's our main +hint because there was you know a row + + align:start position:0% +hint because there was you know a row + + + align:start position:0% +hint because there was you know a row +involved in the problem if you will um + + align:start position:0% +involved in the problem if you will um + + + align:start position:0% +involved in the problem if you will um +so our this the surface that we choose + + align:start position:0% +so our this the surface that we choose + + + align:start position:0% +so our this the surface that we choose +is some big sphere and then we apply the + + align:start position:0% +is some big sphere and then we apply the + + + align:start position:0% +is some big sphere and then we apply the +the extended gausses theorem to the + + align:start position:0% +the extended gausses theorem to the + + + align:start position:0% +the extended gausses theorem to the +solid region between the cube and the + + align:start position:0% +solid region between the cube and the + + + align:start position:0% +solid region between the cube and the +sphere outside the cube but inside the + + align:start position:0% +sphere outside the cube but inside the + + + align:start position:0% +sphere outside the cube but inside the +sphere so because the Divergence of the + + align:start position:0% +sphere so because the Divergence of the + + + align:start position:0% +sphere so because the Divergence of the +field is + + align:start position:0% +field is + + + align:start position:0% +field is +zero the extended guses theorem tells us + + align:start position:0% +zero the extended guses theorem tells us + + + align:start position:0% +zero the extended guses theorem tells us +that the two fluxes the flux over the + + align:start position:0% +that the two fluxes the flux over the + + + align:start position:0% +that the two fluxes the flux over the +cube the flux out of the cube and the + + align:start position:0% +cube the flux out of the cube and the + + + align:start position:0% +cube the flux out of the cube and the +flux out of the sphere actually equal to + + align:start position:0% +flux out of the sphere actually equal to + + + align:start position:0% +flux out of the sphere actually equal to +each other but since the fluxes are + + align:start position:0% +each other but since the fluxes are + + + align:start position:0% +each other but since the fluxes are +actually equal to each other that means + + align:start position:0% +actually equal to each other that means + + + align:start position:0% +actually equal to each other that means +we can just in order to compute the flux + + align:start position:0% +we can just in order to compute the flux + + + align:start position:0% +we can just in order to compute the flux +out of the cube it's enough to compute + + align:start position:0% +out of the cube it's enough to compute + + + align:start position:0% +out of the cube it's enough to compute +the flux out of the sphere okay but + + align:start position:0% +the flux out of the sphere okay but + + + align:start position:0% +the flux out of the sphere okay but +Computing the flux out of the sphere is + + align:start position:0% +Computing the flux out of the sphere is + + + align:start position:0% +Computing the flux out of the sphere is +relatively easy because on the sphere + + align:start position:0% +relatively easy because on the sphere + + + align:start position:0% +relatively easy because on the sphere +the Grand f.n is just + + align:start position:0% +the Grand f.n is just + + + align:start position:0% +the Grand f.n is just +constant and so then we're integrating a + + align:start position:0% +constant and so then we're integrating a + + + align:start position:0% +constant and so then we're integrating a +surface a constant over the surface of a + + align:start position:0% +surface a constant over the surface of a + + + align:start position:0% +surface a constant over the surface of a +sphere and that just gives us the + + align:start position:0% +sphere and that just gives us the + + + align:start position:0% +sphere and that just gives us the +surface area of the sphere times that + + align:start position:0% +surface area of the sphere times that + + + align:start position:0% +surface area of the sphere times that +constant which is 4 Pi r^ 2 * 1 r^ 2 + + align:start position:0% +constant which is 4 Pi r^ 2 * 1 r^ 2 + + + align:start position:0% +constant which is 4 Pi r^ 2 * 1 r^ 2 +which is 4 Pi so the flux out of the + + align:start position:0% +which is 4 Pi so the flux out of the + + + align:start position:0% +which is 4 Pi so the flux out of the +cube then is also equal to 4 + + align:start position:0% +cube then is also equal to 4 + + + align:start position:0% +cube then is also equal to 4 +Pi I'll stop there \ No newline at end of file diff --git a/X3_SfVMyE3k.txt b/X3_SfVMyE3k.txt new file mode 100644 index 0000000000000000000000000000000000000000..3cf216afc33d897d5ae353228037c1e8cde24fad --- /dev/null +++ b/X3_SfVMyE3k.txt @@ -0,0 +1,3209 @@ +The following content is +provided under a Creative + +Commons license. + +Your support will help MIT +OpenCourseWare continue to + +offer high quality educational +resources for free. + +To make a donation or view +additional materials from + +hundreds of MIT courses, visit +MIT OpenCourseWare at + +ocw.mit.edu. + +PROFESSOR: I guess [OBSCURED] + +Let's get going. + +OK, should I introduce you? + +BRADLEY KUSZMAUL: If you want. + +I can introduce myself. + +PROFESSOR: We have Bradley +Kuszmaul who's been doing + +articles on Cilk? + +He's a very interesting +paralleling and also what you + +can say about the program It's +a very interesting project + +that coming for a while, and +there's a lot of interesting + +things he's developed, +and multi core + +becoming very important. + +BRADLEY KUSZMAUL: So how +many of you people have + +ever heard of Cilk? + +Have used it? + +So those of you who have +used it may find + +this talk old or whatever. + +So Cilk is a system that +runs on a shared-memory + +multiprocessor. + +So this is not like the system +you've been programming for + +this class. + +This kind of machine you have +processors, which each have + +cache and some sort of a network +and a bunch of memory + +and when the processors do +memory operations they are all + +on the same address space +and it's typically-- + +the memory system provides some +sort of coherence like + +strong consistency or maybe +released consistency. + +We're interested in the case +where the distance from + +processors to other processors +into a processors to memory + +may be nonuniform and so it's +important to use the cache + +well in this kind of machine +because you can't + +just ignore the cache. + +So sort of the technology that +I'm going to talk about for + +this kind of system +is called Cilk. + +Cilk is a C language and it does +dynamic multithreading + +and it has a provably +good runtime system. + +So I'll talk about what +those all mean. + +Cilk runs on shared-memory +machines like Suns and SGIs + +and well, you probably can't +find Alphaservers anymore. + +It runs on SMPs like that are +in everybody's laptops now. + +There's been several interesting +applications + +written in Cilk including virus +shell assembly, graphics + +rendering, n-body simulation. + +We did a bunch of chess programs +because they were + +sort of the raison +d'etre for Cilk. + +One of the features about Cilk +is that it automatically + +manages a lot of the +low-level issues. + +You don't have to do load +balancing, you don't have to + +write in protocols. + +You basically write programs +that look a lot more like the + +ordinary Cilk programs instead +of saying first I'm going to + +do this and then I'm going to +set this variable and then + +somebody else is going to read +that variable and that's a + +protocol and those are very +difficult to get right. + +AUDIENCE: [OBSCURED] + +BRADLEY KUSZMAUL: Yeah, +I'll mention that + +a little bit later. + +We had award-winning +chess player. + +So to explain what Cilk's about + +I'll talk about Fibonacci. + +Now Fibonacci, this is just to +review in case you don't know + +C. You all know C right? + +So Fibonacci is the function +that each number is the sum of + +the previous two Fibonacci +numbers. + +And this is an implementation +that basically does that + +computation directly. + +The Fibonacci of n if n is +less than 2, it's just n. + +So Fibonacci of zero +is zero, 1 is 1. + +2, the Fibonacci's-- + +well, then you have to do the +recursion, so you compute + +Fibonacci of n minus 1 and +Fibonacci of n minus 2 and sum + +them together and that's +Fibonacci of n. + +One observation about this +function is it's a really slow + +implementation of Fibonacci. + +You all know how to +do this faster? + +How fast can you do Fibonacci? + +You all know this, How +fast is this one? + +AUDIENCE: [OBSCURED]. + +BRADLEY KUSZMAUL: So for those +of you who don't know-- + +certainly know how to compute +Fibonacci in linear time just + +by keeping track of the +most recent two. + +1, 1, 2, 3, 5, you just do it. + +This is exponential time and +there's an algorithm that does + +it in logarithmic time. + +So this implementation is +doubly, exponentially bad. + +But it's good as a didactic +example because it's easy to + +understand. + +So to turn this into Cilk we +just add some key words and + +I'll talk about what the key +words are in a minute, but the + +key thing to understand about +this is if you delete the key + +words you have a C program and +Cilk programs have the + +property that one of the legal +semantics for the Cilk program + +is the C program that you get +by deleting the key words. + +Now there's other possible +semantics + +you could get because-- + +not for this function, this +function always produces the + +same answer because there's +no race conditions in it. + +But for programs that have +races you may have other + +semantics that the system +could provide. + +And so this kind of a language +extension where you can sort + +of delete the extensions and get +a correct implementation + +of the parallel program is +called a faithful extension. + +A lot of languages like OpenMP +have properties that if you + +had these directives and if +you delete them, it will + +change the semantics of your +program and so you have to be + +very careful. + +Now if you're careful about +programming OpenMP you can + +make it so that it's faithful, +that has this property. + +But that's not always +the case that it is. + +Sure. + +AUDIENCE: Is it built +on the different.. + +BRADLEY KUSZMAUL: C 77. + +No, C 89. + +AUDIENCE: OK, so there's +no presumption + +or any alias involved? + +It's assumed that +the [OBSCURED]. + +BRADLEY KUSZMAUL: So the +issue of restricted + +pointers, for example? + +AUDIENCE: Restricted pointers. + +BRADLEY KUSZMAUL: So Cilk +turns out to work + +with C 99 as well. + +AUDIENCE: But is the presumption +though for a + +pointer that it could alias? + +BRADLEY KUSZMAUL: The Cilk +compiler makes no assumptions + +about that. + +If you write a program +and the back end-- + +Cilk works and I'll talk about +this in a couple minutes. + +Cilk works by transforming +this into a C + +program that has-- + +when you run it on one processor +it's just the + +original C program in effect. + +And so if you have a dialect +of C that has restricted + +pointers and a compiler that-- + +PROFESSOR: You're taking +the assumptions that + +if you make a mistake-- + +BRADLEY KUSZMAUL: If you make a +mistake the language doens't + +stop you from making +the mistake. + +AUDIENCE: Well, but in C 89 +there's not a mistake. + +There's no assumption about +aliasing, right? + +It could alias. + +So if I said -- + +BRADLEY KUSZMAUL: Because of +the aliasing you write a + +program that has a race +condition in it, which is + +erroneous-- + +AUDIENCE: It would be valid? + +BRADLEY KUSZMAUL: No, +it'd still be valid. + +It would just have a race in +it and you would have a + +non-determinate result. + +PROFESSOR: It may not +do what you want. + +BRADLEY KUSZMAUL: It may not do +what you want, but one of + +the legal executions of that +parallel program is the + +original C program. + +AUDIENCE: So there's no extra. + +BRADLEY KUSZMAUL: At the sort +of level of doing analysis, + +Cilk doesn't do analysis. + +Cilk is a compiler that compiles +this language and the + +semantics are what they are, +which is you the spawn is + +its-- and I'll talk about +the semantics. + +The spawn means you can run the +function in parallel and + +if that doesn't give you the +same answer every time it's + +not the compilers fault. + +AUDIENCE: [OBSCURED] + +BRADLEY KUSZMAUL: Pardon? + +AUDIENCE: There has to be some +guarantee [OBSCURED]. + +[OBSCURED] + +PROFESSOR: How in a race +condition you get some + +[OBSCURED]. + +BRADLEY KUSZMAUL: One of the +legal things the Cilk system + +could do is just run this, +run that program. + +Now if you're running it on +multiple processors that's not + +what happens because the other +thing is there's some + +performance guarantees we get. + +So there's actually +parallelism. + +But on one processor in fact, +that's exactly what the + +execution does. + +So Cilk does dynamic +multithreading and this is + +different from p threads for +example where you have this + +very heavyweight thread that +costs tens of thousands of + +instructions to create. + +Cilk threads are really small, +so in this program there's a + +Cilk thread that runs basically +from when the fib + +starts to here and then-- + +I feel like there's a missing +slide in here. + +I didn't tell you about spawn. + +OK, well let me tell you about +spawn because what the spawn + +means is that this function +can run in parallel. + +That's very simple. + +What the sync means is that all +the functions that were + +spawned off in this function all +have to finish before this + +function can proceed. + +So in a normal execution of C, +when you call a function the + +parent stops. + +In Cilk the parent can keep +running, so while that's + +running the parent-- this can +spawn off this and then the + +sync happens and now the +parent has to stop. + +And this key word basically just +says that this function + +can be spawned. + +AUDIENCE: Is the sync in that +scope or the children scope? + +BRADLEY KUSZMAUL: The sync is +scoped within the function. + +So you could have a 4 loop +that spawned off a + +whole bunch of stuff. + +AUDIENCE: You could call the +function instead of moving + +some spawns, but +then [OBSCURED] + +in the sync. + +BRADLEY KUSZMAUL: There's an +explicit sync at the end of + +every function. + +So Cilk functions are strict. + +PROFESSOR: [NOISE] + +BRADLEY KUSZMAUL: You know, +there's children down inside + +here, but this function can't +return-- well, if I had + +omitted the sync and down in +some leaf the compiler puts + +one in before the function +returns. + +There's some languages that are +like this where somehow + +the intermediate function can go +away and then you can sync + +directly with your +grandparent. + +AUDIENCE: Otherwise +it would stop. + +BRADLEY KUSZMAUL: So this gives +you this dag, so you + +have this part of the program +that runs up to the first + +spawn and then part of the +program that runs between the + +spawns and the part of the +program that runs after-- + +well, after the last spawn to +the sync and then from there + +to the return. + +So I've got this drawing +that shows this + +function sort of running. + +So first the purple code runs +at it gets to the spawn, it + +spawns of this guy, but now the +second piece of code can + +start running. + +He does a spawn, so these two +are running in parallel. + +Meanwhile. + +This guy started that pff. + +This is a base case, so he's +going to not do anything. + +Just feels like there's +something + +missing in this slide. + +Oh well. + +Essentially now this +guy couldn't run + +going back to here. + +This part of the code couldn't +run until after sync so this + +thing's sitting here waiting. + +So when these guys finally +return then this can run. + +This guy's getting stuck here. + +He runs and he runs. + +These two return and the +value comes up here. + +And now basically the +function is done. + +One observation here is that +there's no mention of the + +number of processors +in this code. + +You haven't specified how +to schedule or how many + +processors. + +All you've specified is this +directed acyclic graph that + +unfolds dynamically and it's +up to us to schedule those + +onto the processors. + +So this code is processor +oblivious. + +It's oblivious to the number +of processors. + +PROFESSOR: But because we're +using the language we're + +probably have to create, write +as many spawns depending on-- + +BRADLEY KUSZMAUL: No, what you +do is you write as many spawns + +as you can. + +You expose all the parallelism +in your code. + +So you want this dag to have +millions of threads in it + +concurrently. + +And then it's up to us to +schedule that efficiently. + +So it's a different mindset +then, I have 4 processors, let + +me create 4 things to do. + +I have 4 processors, let me +create a million things to do. + +And then the Cilk scheduler +guarantees to give you-- you + +have 4 processors, I'll give +you 4 fold speed up. + +PROFESSOR: I guess what you'd +like to avoid is the mindset + +of the programmer has to change +or find the changing + +tuning the parameters +for the performance. + +BRADLEY KUSZMAUL: There's some +tuning that you do in order to + +make the leaf code. + +There's some overhead for +doing function calls. + +So it's small overhead. + +It turns out the cost +of the spawn is like + +three function calls. + +If you were actually trying to +make this code run faster you + +make the base case bigger and do +something, trying to speed + +things up a little bit with +the leaves of this call. + +So there's this call tree +and inside the call + +tree is this dag. + +So it supports C's rule +for pointers. + +For whatever dialect you have. +If you have a pointer to a + +stack and then you have a +pointer to the stack and then + +you call, you're allowed to use +that pointer in C. So in + +Cilk you are as well. + +If you have a parallel thing +going on where normally in C + +you would call A, then B +returns, then C and D. So C + +and D can refer to anything on +A, but C can't legally refer + +to something on B and the same +rule applies to Cilk. + +So we have a data structure that +implements this cactus + +stack is what it's called, after +the sugauro cactus-- + +the view of the imagery +there and it lets you + +support that rule. + +There's some advanced features +in Cilk that have to do with + +speculative execution and I'm +going to skip over those today + +because it turns out that sort +of 99% of the time you don't + +need this stuff. + +We have some debugger support, +so if you've written code that + +relied on some semantics that +maybe you didn't like when you + +went to the parallel world, +you'd like to find out. + +This is a tool that basically +takes a Cilk program and an + +input data set and it runs and +it tells you is there any + +schedule that I could have +chosen-- so it's that directed + +acyclic graph. + +So there's a whole bunch of +possible schedules I could + +have chosen. + +Is there any schedule that +changes the order of two + +concurrent memory operations +where one of them is right? + +So we call this the +non-determinator because it + +finds all the determinacy +races in your program. + +And Cilk guarantees-- the Cilk +race detector is guaranteed to + +find those. + +There's a lot of race detectors +where if the race + +doesn't actually occur you +have two things that are + +logically in parallel, but if +they don't actually run on + +different processors a lot of +race detectors out there in + +the world won't report +the race. + +So you get false negatives and +there's a bunch of false + +positives that show up. + +This basically only gives +you the real ones. + +AUDIENCE: That might be +indicatiors there might be + +still a data to arrays. + +BRADLEY KUSZMAUL: So this +doesn't analyze the program. + +It analyzes the execution. + +So it's not trying to solve some +MP complete problem or + +Turing complete problem. + +And so this reduces the problem +of finding data races + +to the situation that's just +like when you're trying to do + +code release and quality control +for serial programs. + +You write tests. + +If you don't test your program +you don't know what it does + +and that's the same +property here. + +If you do find some race someday +later then you can + +write a test for it and know +that you're testing to make + +sure that race didn't creep +back into your code. + +That's what you want out of a +software release strategy. + +AUDIENCE: [NOISE] + +BRADLEY KUSZMAUL: If you start +putting in sync than maybe the + +race goes away because +of that. + +But if just put in +instrumentation to try to + +figure out what's going, +it's still there. + +And the race detector sort of +says, this variable in this + +function, this variable in this +function, you look at it + +and say, how could +that happen? + +And finally you figured out and +you fix it and then you + +put it-- if you're trying to do +software release you build + +a regression test that will +verify that has that input. + +AUDIENCE: What if you have a +situation where the spawn + +graph falls into a terminal. + +So it's not a radius, but +monitoring spawn is there but + +it spawns a graph a +little bit deeper. + +BRADLEY KUSZMAUL: Yes. + +For example, our race detector +understands locks. + +So part of the rule is it +doesn't report a race if the + +two memory accesses-- + +if there was a lock that they +both held in common. + +Now you now you can write buggy +programs because you can + +essentially do the memory at +lock, you know, read the + +memory, unlock, lock, +write the memory. + +Now the interleave happens +and there's a race. + +So the assumption of this race +detector is that if you put + +locks in there that you've +sort of thought about. + +This is finding races that you +forgot about rather than races + +that you ostensibly +thought about. + +There are some races that +are actually correct. + +For example, in the chess +programs there's this big + +table that remembers all +the chess positions + +that have been seen. + +And if you don't get the right +answer out of the table it + +doesn't matter because you +search it again anyway. + +Not getting the right +answer means you + +don't get any answer. + +You look something up and it's +not there so you search again. + +If you just waited a little +longer maybe somebody else + +would have put the value +in, you could have + +saved a little work. + +And so in that case, well it +turns out to be there's no + +parallel way to do that. + +So I'm willing to tolerate that +race because that gives + +me performance and so you have +what we call fake locks, which + +are basically things that look +like lock calls, but they + +don't do anything except tell +the race detector, pretend + +there was a lock +held in common. + +Yeah? + +AUDIENCE: +[UNINTELLIGIBLE PHRASE] + +BRADLEY KUSZMAUL: If it says +there's no race it means that + +for every possible +scheduling that-- + +AUDIENCE: +[UNINTELLIGIBLE PHRASE]. + +BRADLEY KUSZMAUL: Well, +you have that dag. + +And imagine running it +on one processor. + +There's a lot of possible +orders in + +which to run the dag. + +And the rule is well, was there +a load in a store or a + +store in a store that switched +orders in some possible + +schedule and that's +the definition. + +AUDIENCE: So, in practice, +sorry, one of the [INAUDIBLE] + +techniques is loss. + +Assuming, dependent on the +processor, that you have + +atomic rights, we want to +deal with that data + +[UNINTELLIGIBLE] in +the background -- + +BRADLEY KUSZMAUL: Those +protocols are really hard to + +get right, but yes, it's +an important trick. + +AUDIENCE: Certainly +[INAUDIBLE]. + +BRADLEY KUSZMAUL: So to convince +the race detector not + +to complain you put fake +locks around it. + +You've programmed a +sophisticated algorithm it's + +up to you to get the +details right. + +The other property about this +race detector is that it's + +fast. It runs almost +in liear time. + +A lot of the race detectors that +you find out there run in + +quadratic time. + +So if you want to run a million +instructions it has to + +compare every instruction to +every other instruction. + +Turns out we don't +have to do that. + +We run in time, which is n times +alpha of n where alpha's + +the inverse Ackermann +function. + +Anybody remember that from +the union-find algorithm. + +It's got that graded So it's +like the almost linear time. + +We actually now have a linear +timed one that has performance + +advantages. + +So let me do a little +theory in practice. + +In Cilk we have some fundamental +complexity + +measures that we worry about. + +So we're interested in knowing +and being able to predict the + +runtime of a Cilk program +on P processors. + +So we want to know T sub p, +which is the execution time on + +P processors. + +That's the goal. + +What we've got to work with is +some directed acyclic graph + +that is for a particular input +set and if the program + +determines it and everything +else it's a well defined graph + +and we can come up with some +basic measures of this graph. + +So T sub 1 is the work of the +graph, which is the total time + +it would take to run that +graph on one processor. + +Or if you assume that these +things are all cost unit + +times, just the number +of nodes. + +So for this graph +what's the work? + +I heard teen, but something-- + +18? + +And the critical path +is the longest path. + +And if these nodes weren't unit +time you'd have to weight + +the things according +to actually how + +much time they run. + +So the critical path +here is what? + +9. + +So I think those are right. + +The lower bounds then that you +know is that you don't expect + +the runtime on P processes to be +faster than linear speedup. + +In this model that +doesn't happen. + +It turns out cache +does things. + +It's adding more than +just processors. + +You're adding more cache too. + +So all sorts of things or maybe +it means that there's a + +better algorithm you +should have used. + +So there's some funny things +that happen if you have bad + +algorithms and so forth. + +But in this model you can't have +more than linear speedup. + +You also can't get things done +faster than in linear time. + +This model assumes basically +that these costs of running + +these things are fixed and the +cache has the property that + +changing the order of execution +means that the + +actual costs of the nodes in +the graph change costs. + +So those are lower bounds and +the things that we want to + +know are speedups, so that's +T sub 1 over T sub p. + +And the parallelism of +the graph is T sub + +1 over T sub infinity. + +So the work over the critical +path and we've been calling + +this span sometimes lately. + +Some people call that depth. + +Span is easier to say than +critical path, depth has too + +many other meanings so +I kind of like span. + +So what's the parallelism +for this program? + +18/9. + +We said that T sub 1 was what? + +18. + +The infinity is 9. + +So on average and if you had +an infinite number of + +processors and you scheduled +this as greedy as you good, it + +would take you 9 steps to run +and you would you be doing 18 + +things worth of work. + +So on average there's +two things to do. + +You know, 1 plus 1 plus 1 plus +3 plus 4 plus 4 plus 1 plus 1 + +plus 1 divided by 9 +turns out to be 2. + +So the average parallelism or +just the parallelism of the + +program is T sub 1 over +T sub infinity. + +And this property is something +that's not dependent on the + +scheduler, it's a property +of the program. + +Doesn't depend on how many +processors you have. + +AUDIENCE: [OBSCURED] + +You're saying, you're calling +that the span now? + +Is that the one for +us [OBSCURED] + +BRADLEY KUSZMAUL: That's +too long to say. + +I might as well say critical +path length. + +Critical path length, longest +trace span is a mathematical + +sounding name. + +AUDIENCE: We just like +to steal terminology. + +BRADLEY KUSZMAUL: Well, yeah. + +So there's a theorem due to-- + +Graham and Brent said that +there's some schedule that can + +actually achieve the sum of +those two lower bounds. + +This linear speedup is one lower +bound of the runtime and + +the critical path +is the other. + +So there's some schedule that +basically achieves the sum of + +those and how does that +theorem work? + +Well, at each time +step either-- + +suppose we had 3 processors. + +Either there's at least 3 things +ready to run and so + +what you do is you do +a greedy schedule. + +You grab any 3 of them. + +If there's fewer than p things +to run, like here we have a + +situation where these +have all run. + +The green ones are +ready to go. + +Those are the only 2 that +are ready to go. + +So what do you do then +in a greedy schedule? + +You run them all. + +And the argument goes, well, how +many times steps could you + +execute 3 things? + +At most you could do it the work +divided by the number of + +processors times because +then after that you've + +used up all the work. + +Well how many times could you +execute less than p things? + +Well, every time you execute +less than p things you're + +reducing the length of the +remaining critical path. + +You can't do that more +than the span times. + +And so a greedy scheduler will +achieve some runtime which is + +within the sum of these 2. + +It's actually the sum +of these 2 minus 1. + +It turns out that there has to +be at least one node that's on + +both work and critical path. + +And so that means that you're +guaranteed to be within a + +factor of 2 of optimal with +a greedy schedule. + +And it turns out that if you +have a lot of parallelism + +compared to the number +processors, so if you have a + +graph that has a million fold +parallelism and a thousand + +fold processors Well, if this +is really small compared to + +the work, if you have a graph +with a million fold + +parallelism that means the +critical path is small. + +If you only had 1000 processors +that means this + +term's big. + +And that means that this term is +very close to this term, so + +essentially the corollary to +this is that you get linear + +speedup, perfect linear speed +asymptotically if you have + +fewer processors then you have +parallelism in your program. + +So the game here at this level +of understanding, I haven't + +told you how the scheduler +actually works-- is to write a + +program that's got a lot of +parallelism that you can get + +linear speedup. + +Well, the work-stealing +scheduler we actually use. + +The problem is the greedy +schedulers can be hard to + +compute-- especially if you +imagine having a million + +processors in a program with +a billion fold parallelism. + +Finding on every clock cycle, +finding something for each of + +the million guys to do is +conceptually difficult, so + +instead we have a work-stealing +scheduler. + +I'll talk about that +in a second. + +It achieves bounds which are +not quite as good as those. + +This bound is the same. + +It's the sum of two terms. One +is the linear speedup term, + +but instead of it being T sub +infinity it's big O of T sub + +infinity because you actually +have to do communication + +sometimes if the critical +path length is long. + +Basically, you can +sort of imagine. + +If you have a lot of things to +do, a lot of tasks and people + +to do it, it's easy to do that +in parallel if there's no + +interdependencies +among the tasks. + +But as soon as there's +dependencies you end up having + +to coordinate a lot and that +communication costs-- + +there's lots of lore about +adding programmers to a task + +and it slowing you down. + +Because basically communication +gets you. + +What we found empirically-- + +there's a theorem for this-- + +empirically the runtime is +actually still very close to + +the sum of those terms. Or maybe +it's those terms plus 2 + +times T sub infinity or +something like that. + +And again, we basically get +near-perfect speedup as long + +as the number of processors +is a lot less than the + +parallelism. + +Should be sort of a less +than less than. + +The compiler has the mode where +you basically can insert + +instrumentations. + +So you can run your program, +it'll tell you the critical + +path length. + +You can compute these numbers. + +Clear how to compute work, you +just sum up the runtime of all + +the threads. + +To compute the critical path +length, well you have to do + +some max's and stuff as you +go through the graph. + +And the average cost of a spawn +these days is about 3 on + +like a dual core pentium. + +Three times the cost +of a function call. + +And most of that cost actually +has to do with the memory + +barrier that we do at the spawn +because that machine + +doesn't have strong +consistencies. + +So you have to put this memory +barrier in and that just + +empties all the pipelines. + +It does better on like an SGI +machine, which has strong-- + +well, traditional. + +A MIPS machine that has strong +consistency actually does + +better for the cost +of that overhead. + +Let me talk a little +bit about chess. + +And we had a bunch of chess +programs. I wrote one in 1994, + +which placed third at the +International Computer Chess + +Championship and that was +running on a big connection + +machine CM5. + +I was one of the architects +of that machine, so + +it was double fun. + +We wrote another program that +placed second in '95 and that + +was running on an 1800 node +Paragon and that was a big + +computer back then. + +We built another program called +Cilk chess, which + +placed first in '96 running on +a relatively smaller machine. + +And then on a larger SGI origin +we ran some more and + +then at the World Computer Chess +Championship in 1999 we + +beat Deep Blue and +lost to a PC. + +And people don't realize this, +but at the time that Deep Blue + +beat Kasparov it was not the +World Computer Chess + +Champion, a PC was. + +So what? + +It's running a program. + +You know, there's this +head and a tape. + +I don't know what it did. + +So this was a program called +Fritz, which is a commercially + +available program. + +And those guys were very good, +the PC guys playing were very + +good at getting on sort +of the algorithm side. + +We got advantage +by brute force. + +And we also had some real chess +expertise on our team, + +but those guys were spending +full time on things like + +pruning away sub-searches that +they were convinced weren't + +going to pan out. + +Computer chess programs spend +most of their time looking at + +situations that any person would +look at and say, ah, + +blacks won. + +Why are you even looking +at this? + +And it keeps searching. + +It's like, well maybe there's +a way to get the queen. + +So computers are pretty +dumb at that. + +So basically these guys put a +lot more chess intelligence in + +and we also lost due to what-- +in this particular game, we + +were tied for first place and we +decided to do a runoff game + +to find out who would win and +we lost due to a classic + +horizon effect. + +So it turns out that we were +searching to depth 12 in the + +tree and Fritz was searching +to depth 11. + +Even with all these heuristics +and stuff they had in it, they + +were still not searching +as deeply as we were. + +But there was a move that was a +good move that looked OK at + +depth 11 and looked bad at depth +11 and at depth 13 it + +looked really good again. + +So they saw the move and made +it for the wrong reason, we + +saw the move and didn't make it +for the right reason, but + +it was wrong and the right +move-- if we'd been able to + +search a little deeper, we would +have seen that it was + +really the wrong thing to do. + +This happens all the +time in chess. + +There's a little randomness +in there. + +This horizon effect shows up +and again, it boils down to + +the programs are not +intelligent. + +A human would look at it and +say, eventually that knight's + +going to fall. + +But if the computer can't see +it with a search, you know? + +We plotted the speedup of star +Socrates, which was the first + +one on this funny graph. + +So this looks sort of like a +typical linear speedup graph. + +Sort of when you're down here +with few numbers processors + +you get good linear speedup +and eventually you stop + +getting linear speedup. + +That's sort of in broad +strokes what + +this graph looks like. + +But the axes are +kind of funny. + +The axes aren't the number of +processors and the speedup-- + +it's the number processors +divided by the parallelism of + +the program. + +And here is the speedup divided +by the parallelism of + +the program. + +And the reason we did that is +the each of these data points + +is a different program with +different work in span. + +If I'm trying to run a +particular problem on a bunch + +of different processors I can +just draw that curve and see + +what happens as get +more processors. + +I'm not getting any advantage +because I've got too many + +processors. + +I've exceeded the parallelism +of the program. + +But if I'm running, trying +to compare two different + +programs, how do I do that? + +Well, you can do that by +normalizing by the + +parallelism. + +So down in this domain the +number of processors is small + +compared to the average +parallelism and we get good + +linear speedups. + +And up in this the domain the +number of processors is large + +and it starts asymptoting to +the point where the speedup + +approaches the parallelism and +that's sort of what happened. + +You get some noise out here so +one of the things down here, + +it's nice and tight. + +And that's because we're in +that domain where the + +communication costs are +infrequently paid because + +there's lots of work to do. + +You don't have to communicate +very much. + +Up here there's a lot of +communication that happens and + +so the noise is showing +up more in the data. + +This curve here is the +T sub 1 over P plus T + +sub infinity curve. + +The T sub P equals T sub +infinity curve and that's the + +linear speedup curve +on this graph. + +So I think there's an important +lesson in this graph + +besides the data itself, which +is if you're careful about + +choosing the axes, you can take +a whole bunch of data + +that you couldn't see how to +plot it together and you can + +plot it together and get +something meaningful. + +So in my Ph.D. thesis I had +hundreds of little plots for + +each chess position and I didn't +figure out how-- it's + +like they all look +the same, right? + +But I didn't sort of figure out +that if I was careful I + +could actually make +them be the same. + +That happened after I +published my thesis. + +Oh, we could just +overlay them. + +Well, what's the normalization +that makes that work? + +So there's a speedup paradox +that happened. + +Pardon? + +AUDIENCE: [OBSCURED] + +BRADLEY KUSZMAUL: Yeah, OK. + +There was a speedup paradox that +happened while we were + +developing star Socrates. + +We were developing this for +512 processor connection + +machine that was at University +of Illinois, but we only had a + +smaller machine on which +to do our development. + +We had a 128 processor machine +at MIT and most days I could + +only get 32 processors +because the machine + +was in heavy demand. + +So we had this program +and it ran on 32 + +processors in 65 seconds. + +And one of the developers said, +here's a variation on + +the algorithm, it +changes the dag. + +It's a heuristic. + +It makes the program +run more efficient. + +Look, it runs in only 40 seconds +on 32 processors. + +And so is that a good idea? + +It sure seemed like a good idea, +but we were worried that + +we knew that the transformation +increased the + +critical path length of the +program, so we weren't sure it + +was a good idea. + +So we did some calculation. + +We measured the work +and the speedup. + +And so the work here-- + +these numbers have been cooked +a little bit to make the math + +easy, but the numbers-- + +this really did happen, but not +with these exact numbers. + +So we had a work which was 2048 +seconds and only 1 second + +of critical path. + +And over this new program had +only 1/2 as much work to do, + +but the critical path +length was longer. + +It was 8 seconds long. + +If you predict on 32 processors +what the runtime's + +going to be that formula +says well, 65 seconds. + +If you predict it on 32 +processors this-- well, it's + +40 seconds and that looks good, +but we were going to be + +running the tournament on 512 +processors where this term + +would start being less important +than this term. + +So this really did happen and +we actually went back and + +validated that these numbers +were right after we did the + +calculation and it allowed us to +do the engineering to make + +the right decision and not be +misled by something that + +looked good in the +test environment. + +We were able to predict what was +going to happen on the big + +machine without actually having +access to the big + +machine and that was +very important. + +Let me do some algorithms. You +guys probably have done some + +matrix multipliers over the +past 3 weeks, right? + +That's probably the only thing +you've been able to do would + +be my guess. + +So matrix multiplication +is this operation. + +I won't talk about it, but +you know what it is. + +In Cilk instead of doing the +standard triply nested loops + +you do divide and conquer. + +We don't parallelize loops we +parallelize function calls, so + +you want to express a +loops as recursion. + +So to multipliy two big matrices +you do a whole bunch + +of little matrix multiplications +of the + +sub-blocks and then you express +those little matrix + +multiplications themselves and +go off and recursively do + +smaller matrix multiplications. + +So this requires 8 +multiplications of matrices + +these of 1/2 the number of +rows and 1/2 the number + +columns an one edition at the +end where you add these two + +matrices together. + +That's the algorithm that we do, +it's the same total work + +as the standard one, but it's +just expressed recursively. + +So a matrix multiply is you +do these 8 multiplies. + +I had to create a temporary +variable, so the first four + +multiplies the A's and B's +into C. The second four + +multiply the A's and B's into +T and then I have to add T + +into C. So I do all those +spawns, do all the multiplies. + +I do a sync because I better not +start using the results on + +the multiplies and adding them +until the multiplies are done. + +AUDIENCE: Which four +do you add? + +BRADLEY KUSZMAUL: What? + +There's parallelism in add. + +Matrix addition. + +AUDIENCE: Yeah, but it doesn't +add spawn extent + +BRADLEY KUSZMAUL: Well, +we spawn off add. + +I don't understand-- + +[INTERPOSING VOICES] + +BRADLEY KUSZMAUL: So you have +to spawn Cilk functions even + +if you're only executing +one of them at a time. + +Cilk functions are spawned, +C functions are called. + +It's a decision that's built +into the language. + +It's not really a fundamental +decision. + +It's just that's the +way we did it. + +AUDIENCE: Why'd you choose to +have the key word then? + +That's just documentation +from the caller side? + +BRADLEY KUSZMAUL: Yeah, we found +we were less likely to + +make a mistake if we sort of +built it into the type system + +in this way. + +But I'm not convinced that this +is the best way to do + +this type system. + +AUDIENCE: Can the C functions +spawn a Cilk function. + +BRADLEY KUSZMAUL: No. + +You can only call spawn, spawn, +spawn, spawn then you + +can call C functions +at the leaves. + +It turns out you can actually +spawn Cilk functions if you're + +a little clever about-- there's +a mechanism for a Cilk + +system running in the background +and if you're + +running C you can +say OK, do this + +Cilk function in parallel. + +So we have that, but that's +not didactic. + +AUDIENCE: Sorry, I +have a question + +about the sync spawning. + +Is the sync actually doing a +whole wave or -- like, in the + +case of-- maybe not in the case +of the add here, but in + +plenty of other practical +functions you get inside the + +spawn function looking +at the tendencies of + +the parameters, right? + +Based on how those +were built from + +previous spawned funcitons. + +You can actually just start +processing so long as it's + +guaranteed that the results +are available before you + +actually read them. + +BRADLEY KUSZMAUL: So there's +this other style of expressing + +parallelism which you see +in some of the data flow + +languages where you say well, +I've computed this first + +multiply, why can't I get +started on the corresponding + +part of the addition. + +And it turns out that in those +models there's no performance + +guarantees. + +The real issue is you +run out of memory. + +It's a long topic, let's not +go into it, but there's a + +serious technical issue with +those programming models. + +We have very tight memory +bounds as well, so we + +simultaneously get these good +scheduling bounds and good + +memory bounds and if you are +doing that you could have sort + +of a really large number of +temporaries required and run + +out of memory. + +The data flow machine used to +have this number-- there was a + +student, Ken Traub, who was +working on Monsoon when Greg + +Papadapolous was here and he +came up with this term which + +we called Traub's constant, +which was how long the machine + +could be guaranteed to run +before it crashed from being + +out of memory. + +And that was-- well, he took +the rate at which it Kahn's + +divided by the amount of +memory and that was it. + +And many data flow programs had +that property that Monsoon + +could run for 40 seconds +and then after + +that you never knew. + +It might start crashing at any +moment, so everybody wrote + +short data flow programs. + +So one of the things you +actually do when you're + +implementing, when you're trying +to engineer this to go + +fast, is you course in the +base case, which I didn't + +describe up there. + +You don't just do a 1 by 1 +matrix multiplied down there + +at the leaves of +this recursion. + +Because then you're not using +the processor pipeline + +efficiently. + +You call the Intel Math Kernel +Library or something on an 8 + +by 8 matrix so that it really +gets the pipeline a + +chance to chug away. + +So analysis. + +This matrix addition operation-- +well, what's the + +work for matrix addition? + +Well the work to do a matrix +operation on n rows is well, + +you have to do 4 additions +of size n over 2. + +Plus there's order 1 work +here for the sync. + +And that recurrence has solution +order n squared. + +Well, that's not surprising. + +You have to add up 2 matrices +which are n by n. + +That's going to be n squared +so that's a good result. + +The critical path for this is +well, you have to do all of + +these in parallel. + +So whatever the critical path of +the longest one is, they're + +all the same so it's just the +critical path of the size n + +over 2 plus quarter 1, so the +critical path is order log n. + +For matrix multiplication, +sort of the reason I + +do this is I can. + +This is a model which I can +do this analysis, so + +I have to do it. + +But really, being able to do +this analysis is important + +when you're trying to make +things run faster. + +Matrix multiplication, well, +the work is I have to do 8 + +little matrix multiplies plus +I have to do the matrix add. + +The work has solution order n +cubed and everybody knows that + +there's order n cubed multiply +adds in a matrix multiplier, + +so that's not very surprising. + +The critical path is-- well, I +have to do a add so that takes + +log n, plus I have to do a +multiply on a matrix that's + +1/2 the size. + +So the critical path length of +the whole thing has solution + +order log squared n. + +So the total parallelism of +matrix multiplication is the + +work over the span, which is +n cubed over log squared n. + +So if you have a 1000 by 1000 +matrix that means your + +parallelism is close +to 10 million. + +There's a lot of parallelism +and in fact, we see perfect + +linear speedup on matrix +multiply because there's so + +much parallelism in it. + +It turns out that this stack +temporary that I created so + +that I could do these multiplies +all in parallel is + +actually costing me work because +I'm on a machine that + +has cache and I want to use +the cache effectively. + +So I really don't want to create +a whole big temporary + +matrix and blow my cache +out if I can avoid it. + +So I proposed the following +matrix multiply, which is I + +first do 4 of the matrix +multiplies into C1 then I do a + +sync and then I do the other +4 into C1 and another sync. + +And I forgot to do the add-- oh, +no those are multiply adds + +so they're multiplying +and adding in. + +And this saves space because it +doesn't need a temporary, + +but it increases the +critical path. + +So is that a good idea +about or a bad idea? + +Well, we can answer part of that +question with analysis. + +Saving space we know is going +to save something. + +What does it do to the work +in critical path? + +Well, the work is still the +same, it's n cubed because we + +didn't change the number of +flops that we're doing. + +But the critical +path has grown. + +Instead of doing 1 times a +matrix multiply, we have to do + +one and then sync and +then do another one. + +So it's 2 matrix multiplies of +1/2 the size plus the order 1 + +and that recurrence has solution +order n instead of + +order log squared n. + +So that sounds bad, we've made +the critical path longer. + +AUDIENCE: [OBSCURED] + +BRADLEY KUSZMAUL: What? + +Yeah. + +So parallelism is now order n +squared instead of n cubed + +over log squared n and for a +1000 by 1000 matrix that means + +you still have a million +fold parallelism. + +So for relatively modest sized +matrices you still have plenty + +of work to do this +optimization. + +So this is a good transformation +to do it. + +One of the advantages of Cilk +is that you can do this kind + +of You could say, let me +do an optimization. + +I can do an optimization in my +C code and I get to take + +advantage of it in +the Cilk code. + +I could do this kind of +optimization of trading work + +for parallelism. + +If I have a lot of work that +sometimes is a good idea. + +Ordinary matrix multiplication +just is really bad. + +Basically you can imagine +spawning off the n squared + +inner dot products here and + +computing them all in parallel. + +It has work n cubed +parallelism log n. + +I mean, critical path log n so +the parallelism's even better. + +It's n cubed over log n +instead of n squared. + +That looks better theoretically, +but it's really + +bad in practice because it has +such poor cache behavior. + +So we don't do that. + +I'll just briefly talk +about how it works. + +So Cilk does work-stealing. + +We had did double ended +queue-like decque. + +So at the bottom of the queue +is the stack where you push + +and pop things and the top is +something where you can pop + +things off if you want to. + +And so what's running is all +these processors are running + +each on their own stack. + +They're all running the +ordinary serial code. + +That's sort of the +basic situation. + +They're pretty much +running the serial + +code most of the time. + +So some processor runs. + +It pushes. + +Well, it doesn't spawn, +so what does it do? + +It pushes something onto its +stack because it's just a + +function call. + +And it does another couple more +spawns so things pop off. + +Somebody returns so +he pops his stack. + +So far everything's going on, +they're not communicating, + +they're completely independent +computations. + +This guy spawns and now +he's out of work. + +Now he has to do something. + +What he does is he goes and +picks another processor at + +random and he steals +the thing from the + +other end of the stack. + +So he's unlikely to conflict +because this guy's pushing and + +popping down here, but there's +a lock in there, thers's a + +little algorithm. + +A non-blocking algorithm +actually, it's not lock. + +And so he goes and he steals +something and come on, slide + +over there. + +Whoa. + +Yes, that's animation, right? + +That's the extent +of my animation. + +And then he starts +working away. + +And the theorem is that a +work-stealing scheduler like + +this gives expected running +time with high probability + +actually of T sub 1 over P +plus T sub infinity on P + +processors. + +And the pseudoproof is a little +bit like the proof for + +Brent's Theorem, +which is either + +you're working or stealing. + +If you're working well, that +goes against T sub 1 over P. + +You can't do that very much +or you run out of work. + +If you're stealing well, each +steal has a chance that it + +steals the thing that's +on the critical path. + +You may actually steal the wrong +thing, but you actually + +have a 1 in P chance that you're +the one who steals the + +thing that it's on the critical +path and then in + +which case the expected +number-- + +so you had this chance of +1 over P of reducing the + +critical path length by 1, so +after this many steals the + +critical path is all gone. + +So you can only do P times +T infinity steals. + +This high probability +it comes out. + +And that gives you +these bounds. + +OK, I'm not going to give +you all this stuff. + +Message passing sucks, +you know. + +You guys know. + +There's probably nothing +else in here. + +So basically the pitch here is +that you get some high level + +linguistics support for these +very fine-grained parallelism. + +It's an algorithmic programming +model so that + +means that you can do +engineering for performance. + +There's fairly easy conversion +of existing code, especially + +when you combine it with +the race detector. + +You've got this factorization +of the debugging problem and + +to debugging your serial code +is you run it with all the + +Cilk stuff turned off. + +You allied the program and make +sure your program works. + +Then you run it with the rate +detector to make sure you get + +the same answer in parallel +and then you're done. + +Applications in Cilk don't just +scale to large number of + +processors, they scale down +to small numbers, which is + +important if you only have +two processors or one. + +You don't suddenly want to pay +a factor of 10 to get off the + +ground, which happens +sometimes on + +clusters running MPI. + +You have to pay a big +overhead before + +you've made any progress. + +And one of the advantages for +example is that the number of + +processors might change +dynamically. + +In this model that's +OK because it's + +not part of the program. + +So you may have the operating +system reduce the number of + +actual worker threads that you +have doing that work-stealing + +and that can work. + +One of the bad things about +Cilk is that it doesn't + +support sort of data parallel +or program model kind of + +parallelism. + +You really have to think of +things as this divide and + +conquer kind of the world. + +And if you have trouble +expressing that-- + +situations where you're doing +Jacobi update and you very + +carefully put things on, had +each processor work on its + +local memory and then they only +have to communicate at + +the boundaries. + +That's difficult to do right +in Cilk because essentially + +every time you go around the +loop of I have all these + +things to do. + +All the work-stealing happens +randomly and it happens on a + +different processor. + +So it's not very good at that +sort of thing, although it + +turns out Jacobi update's not +a very good example for that + +because there are more +sophisticated algorithms that + +use cache effectively that you +can express in Cilk and I + +would have no idea how to no +say those in some of these + +sort of data parallel +languages. + +Using the cache efficiently is +really important on modern + +processors. + +PROFESSOR: Thank you. + +Questions? + +BRADLEY KUSZMAUL: You can +download Cilk, there's a bunch + +of contributors. + +Those are the Cilk worms +and you can download + +Cilk off our webpage. + +Just Google for Cilk +and you'll find it. + +It's a great language, +you'll love it. + +You'll love it much more than +what you've been doing. + +AUDIENCE: How does the Cilk +play with processor + +[OBSCURED]? + +BRADLEY KUSZMAUL: Well, you +have to have a language, a + +compiler that can +generate those. + +If you have an assembly command +or you have some other + +complier that can +generate those. + +So I just won the HPC challenge, +which is this + +challenge where everybody tries +to run parallel programs + +and argue that they +get productivity. + +For that there were some codes +like matrix multiply and LUD + +composition with pivoting. + +Basically at the leads of the +computation I call the Intel + +Math Kernel Library. + +Which in turn uses the +SSE instructions. + +You could do anything you can do +in C in the C parts of the + +code because Cilk compiler just +passes those through. + +So if you have some really +efficient pipeline code for + +doing something, up to +some point it made + +sense to use that. + +AUDIENCE: [OBSCURED] + +BRADLEY KUSZMAUL: So I ran +it on NASIS Columbia. + +So the benchmark consists of-- +well, there's 7 applications + +they have. 6 of which are +actually well-defined. + +One of them is this thing that +just measures network + +performance or something, +so it doesn't + +have any real semantics. + +There's 6 benchmarks. + +One of them is LUD composition, +one of them is + +DJEM matrix multiplication and +this FFT and 3 others. + +So I implemented all 6, nobody +else implemented all 6. + +It turns out that you had to +implement 3 in order to enter. + +Almost everybody implemented 3 +or 4, but I did all 6 which is + +part of why I won. + +So I could argue that in +a weeks work I just + +implemented-- + +AUDIENCE: What is [OBSCURED]? + +BRADLEY KUSZMAUL: So the prize +has two components. + +Performance and productivity or +elegance or something and + +it's completely whatever the +judges want that to be. + +So it was up to me as a +presenter to make the case + +that I was elegant. + +Because I had my performance +numbers, which were pretty + +good and it turned out that the +IBM entry for x10 did me + +more good than I did, I think. + +Because they got up there and +they compared the performance + +of x10 to their Cilk +implementation and their x10 + +thing was almost as +good as Cilk. + +So after that I think the judges +said they had to give + +me the prize. + +So basically, it went down to +supercomputing and each of us + +got 5 minutes to present and +there were 5 finalists. + +We did our presentation and +then they gave out the -- + +So they divided the prize three +ways: the people who got + +the absolute best performance, +which were some people running + +UPC and the people who had the +most elegance based on minimal + +number of lines of codes and +that was Cleve at -- + +what's his name? + +The Mathworks guy, MATLAB guy. + +Who said, look, matrix, +LUD composition. + +LU of P. It's very elegant, +but I don't think that it + +really sort of explains what +you have to do to solve the + +problems. So he won the prize +for most elegant and I got the + +prize for best combination, +which they then changed-- + +in the final citation for the +prize they said, most + +productivity. + +That was the prize. + +So I actually won the contest +because that was what the + +contest was supposed to be +was most productivity. + +But I only won 1/3 of the +prize money because they + +divided it three ways. + +PROFESSOR: Any other question? + +Thank you. + +BRADLEY KUSZMAUL: Thank you. + +PROFESSOR: We'll take a 5 minute +break and since you had + +guest lecturer I do +have [OBSCURED] \ No newline at end of file diff --git a/X4Y9n_c1ej8.txt b/X4Y9n_c1ej8.txt new file mode 100644 index 0000000000000000000000000000000000000000..3ef495a7e6be9c3008215f8dfbc58d12481c1a08 --- /dev/null +++ b/X4Y9n_c1ej8.txt @@ -0,0 +1,180 @@ +PROFESSOR: Hello, +welcome again to 8701. + +In this short video, I'll talk +about the books we are using + +and the literature we +are using in this class. + +So let's dive right into. + +There's a sequence +of textbooks I + +go back to when I prepare +the material for the class. + +You know, the one +which I use in order + +to derive the outline or +the schedule for the class + +is Introduction to High +Energy Physics by Perkins. + +But again, I use +material from a sequence + +of textbooks and reading +material for you guys as well. + +Nuclear physics is not +covered in Perkins, + +so we have here Samuel Wong's +book on Introductory Nuclear + +Physics. + +We spend about two weeks +talking about nuclear physics + +towards the second +part of the class. + +And a couple of basics, we talk +about the introductory material + +really in the sequence. + +A book I like a lot +is the Introduction + +to Elementary +Particles by Griffiths. + +And you see me using examples +out of that book a bit. + +Then on the nuclear physics +side there is Kenneth Krane. + +It's an MIT book +and a book which + +has been put together by +MIT faculty and research + +scientists. + +And then there's Techniques for +Nuclear and Particle Physics + +by Leo, which I like a lot. + +It's a little bit +of an older book, + +but it goes into some +of the technical details + +and material details which +are important to understand + +how we build detectors. + +And then a more recent book +is Modern Particle Physics + +by Mark Thomson. + +It dives right into particle +physics, the energy frontier. + +And it's really nice to read. + +It's a modern book. + +And it's easy to +read and comprehend. + +I recommend to have a look +at the review articles + +by the particle data group. + +They are really +concise articles which + +are for beginners or for +introductory level maybe + +a little bit +difficult. But as we + +go through the +material in this class, + +you should be able to take +those articles to review + +certain sections of this class. + +For example, QCD, or +electroweak interactions, + +the Higgs mechanism. + +And while you do +this, you also learn + +one of the latest results +and measurement in this area. + +I'll be posting a set of papers +as we go through the class. + +And you'll see in the +course organization + +that I'll ask you to +actually summarize + +some of those papers in +our recitation section. + +So those are going to be +important papers, for example, + +describing the +experiment which was used + +to measure parity violation, +or the paper on the Higgs + +discovery. + +That's it for literature. + +Please as always go ahead +and ask me questions. + +You know this. + +You know if you Google particle +physics or nuclear physics, + +you will find tons of +literature available + +on as many good books. + +And you might find +a different one + +from this listing which +suits your appetite + +for reading and learning. \ No newline at end of file diff --git a/XAt0dX5M-TA.txt b/XAt0dX5M-TA.txt new file mode 100644 index 0000000000000000000000000000000000000000..5c653d9cff078755d8e582c5899b29691d25fdc5 --- /dev/null +++ b/XAt0dX5M-TA.txt @@ -0,0 +1,1323 @@ +align:start position:0% + +welcome back to + + align:start position:0% +welcome back to + + + align:start position:0% +welcome back to +age 20 special relativity in this video + + align:start position:0% +age 20 special relativity in this video + + + align:start position:0% +age 20 special relativity in this video +we talk about galilean transformation so + + align:start position:0% +we talk about galilean transformation so + + + align:start position:0% +we talk about galilean transformation so +what is it you're going to do you want + + align:start position:0% +what is it you're going to do you want + + + align:start position:0% +what is it you're going to do you want +to describe our event p + + align:start position:0% +to describe our event p + + + align:start position:0% +to describe our event p +maybe professor cluj exploding + + align:start position:0% +maybe professor cluj exploding + + + align:start position:0% +maybe professor cluj exploding +um it's two different reference frame we + + align:start position:0% +um it's two different reference frame we + + + align:start position:0% +um it's two different reference frame we +can call one of the reference frame our + + align:start position:0% +can call one of the reference frame our + + + align:start position:0% +can call one of the reference frame our +laboratory frame + + align:start position:0% +laboratory frame + + + align:start position:0% +laboratory frame +maybe that's the frame in which + + align:start position:0% +maybe that's the frame in which + + + align:start position:0% +maybe that's the frame in which +professor clutter was stationary it has + + align:start position:0% +professor clutter was stationary it has + + + align:start position:0% +professor clutter was stationary it has +an origin and has axis x y and z + + align:start position:0% +an origin and has axis x y and z + + + align:start position:0% +an origin and has axis x y and z +and then we have a moving frame which is + + align:start position:0% +and then we have a moving frame which is + + + align:start position:0% +and then we have a moving frame which is +moving with a constant velocity + + align:start position:0% +moving with a constant velocity + + + align:start position:0% +moving with a constant velocity +with respect to the laboratory frame + + align:start position:0% +with respect to the laboratory frame + + + align:start position:0% +with respect to the laboratory frame +the origin is o prime the axes are x + + align:start position:0% +the origin is o prime the axes are x + + + align:start position:0% +the origin is o prime the axes are x +prime y prime and z prime + + align:start position:0% +prime y prime and z prime + + + align:start position:0% +prime y prime and z prime +all right so now what did we learn from + + align:start position:0% +all right so now what did we learn from + + + align:start position:0% +all right so now what did we learn from +this let's think about an example + + align:start position:0% + + + + align:start position:0% + +an example most of you have experienced + + align:start position:0% +an example most of you have experienced + + + align:start position:0% +an example most of you have experienced +before is the one where you sit in a + + align:start position:0% +before is the one where you sit in a + + + align:start position:0% +before is the one where you sit in a +train car and if it's not a train car it + + align:start position:0% +train car and if it's not a train car it + + + align:start position:0% +train car and if it's not a train car it +can be a + + align:start position:0% +can be a + + + align:start position:0% +can be a +car or a plane something which is moving + + align:start position:0% +car or a plane something which is moving + + + align:start position:0% +car or a plane something which is moving +with respect to earth + + align:start position:0% +with respect to earth + + + align:start position:0% +with respect to earth +if you look out of the window + + align:start position:0% +if you look out of the window + + + align:start position:0% +if you look out of the window +and you know the acceleration is very + + align:start position:0% +and you know the acceleration is very + + + align:start position:0% +and you know the acceleration is very +very minor + + align:start position:0% +very minor + + + align:start position:0% +very minor +it's often not clear whether or not the + + align:start position:0% +it's often not clear whether or not the + + + align:start position:0% +it's often not clear whether or not the +earth the train station or the train car + + align:start position:0% +earth the train station or the train car + + + align:start position:0% +earth the train station or the train car +is moving and so you have + + align:start position:0% +is moving and so you have + + + align:start position:0% +is moving and so you have +this this kind of + + align:start position:0% +this this kind of + + + align:start position:0% +this this kind of +weird feeling that you know i don't know + + align:start position:0% +weird feeling that you know i don't know + + + align:start position:0% +weird feeling that you know i don't know +if maybe the neighboring train started + + align:start position:0% +if maybe the neighboring train started + + + align:start position:0% +if maybe the neighboring train started +moving or i'm i'm moving um but what you + + align:start position:0% +moving or i'm i'm moving um but what you + + + align:start position:0% +moving or i'm i'm moving um but what you +want to do here is describe + + align:start position:0% +want to do here is describe + + + align:start position:0% +want to do here is describe +you sitting in the train car + + align:start position:0% +you sitting in the train car + + + align:start position:0% +you sitting in the train car +um you know reading a newspaper uh once + + align:start position:0% +um you know reading a newspaper uh once + + + align:start position:0% +um you know reading a newspaper uh once +with + + align:start position:0% +with + + + align:start position:0% +with +within your laboratory frame within the + + align:start position:0% +within your laboratory frame within the + + + align:start position:0% +within your laboratory frame within the +frame of the train and then you want to + + align:start position:0% +frame of the train and then you want to + + + align:start position:0% +frame of the train and then you want to +describe the very same events or + + align:start position:0% +describe the very same events or + + + align:start position:0% +describe the very same events or +sequence of events + + align:start position:0% +sequence of events + + + align:start position:0% +sequence of events +in + + align:start position:0% +in + + + align:start position:0% +in +the frame of the stationary train + + align:start position:0% +the frame of the stationary train + + + align:start position:0% +the frame of the stationary train +station + + align:start position:0% +station + + + align:start position:0% +station +all right let's look at a specific + + align:start position:0% +all right let's look at a specific + + + align:start position:0% +all right let's look at a specific +example + + align:start position:0% +example + + + align:start position:0% +example +here again our professor is exploding at + + align:start position:0% +here again our professor is exploding at + + + align:start position:0% +here again our professor is exploding at +a time + + align:start position:0% +a time + + + align:start position:0% +a time +tp + + align:start position:0% +tp + + + align:start position:0% +tp +at xp yp and zp + + align:start position:0% +at xp yp and zp + + + align:start position:0% +at xp yp and zp +to make this a little bit easier + + align:start position:0% +to make this a little bit easier + + + align:start position:0% +to make this a little bit easier +we define at time t equals zero the + + align:start position:0% +we define at time t equals zero the + + + align:start position:0% +we define at time t equals zero the +origin of the two frames coincide that + + align:start position:0% +origin of the two frames coincide that + + + align:start position:0% +origin of the two frames coincide that +just means that + + align:start position:0% +just means that + + + align:start position:0% +just means that +at the origin we have two clocks two + + align:start position:0% +at the origin we have two clocks two + + + align:start position:0% +at the origin we have two clocks two +watches and we make sure that they're + + align:start position:0% +watches and we make sure that they're + + + align:start position:0% +watches and we make sure that they're +synchronized + + align:start position:0% +synchronized + + + align:start position:0% +synchronized +right and then you know my watch stays + + align:start position:0% +right and then you know my watch stays + + + align:start position:0% +right and then you know my watch stays +with me and then there's a second watch + + align:start position:0% +with me and then there's a second watch + + + align:start position:0% +with me and then there's a second watch +maybe with you um + + align:start position:0% +maybe with you um + + + align:start position:0% +maybe with you um +which + + align:start position:0% +which + + + align:start position:0% +which +you know + + align:start position:0% +you know + + + align:start position:0% +you know +moves along and those are great watches + + align:start position:0% +moves along and those are great watches + + + align:start position:0% +moves along and those are great watches +they're synchronized + + align:start position:0% +they're synchronized + + + align:start position:0% +they're synchronized +you also want to simplify you can always + + align:start position:0% +you also want to simplify you can always + + + align:start position:0% +you also want to simplify you can always +define the + + align:start position:0% +define the + + + align:start position:0% +define the +direction of our coordinate system such + + align:start position:0% +direction of our coordinate system such + + + align:start position:0% +direction of our coordinate system such +that the velocity + + align:start position:0% +that the velocity + + + align:start position:0% +that the velocity +the relative velocity between the two + + align:start position:0% +the relative velocity between the two + + + align:start position:0% +the relative velocity between the two +reference frame is in one specific + + align:start position:0% +reference frame is in one specific + + + align:start position:0% +reference frame is in one specific +direction here i decided to use x i + + align:start position:0% +direction here i decided to use x i + + + align:start position:0% +direction here i decided to use x i +could have used y and z and i could + + align:start position:0% +could have used y and z and i could + + + align:start position:0% +could have used y and z and i could +rotate them + + align:start position:0% +rotate them + + + align:start position:0% +rotate them +rotate the coordinate systems or the + + align:start position:0% +rotate the coordinate systems or the + + + align:start position:0% +rotate the coordinate systems or the +relative movement of the coordinate + + align:start position:0% +relative movement of the coordinate + + + align:start position:0% +relative movement of the coordinate +systems in any way it's just a + + align:start position:0% +systems in any way it's just a + + + align:start position:0% +systems in any way it's just a +simplification here + + align:start position:0% +simplification here + + + align:start position:0% +simplification here +when i do that i can rewrite this event + + align:start position:0% +when i do that i can rewrite this event + + + align:start position:0% +when i do that i can rewrite this event +p + + align:start position:0% +p + + + align:start position:0% +p +in the s s + + align:start position:0% +in the s s + + + align:start position:0% +in the s s +prime frame through the s frame in the + + align:start position:0% +prime frame through the s frame in the + + + align:start position:0% +prime frame through the s frame in the +following way so for x we find + + align:start position:0% +following way so for x we find + + + align:start position:0% +following way so for x we find +that x p is given by x prime p is given + + align:start position:0% +that x p is given by x prime p is given + + + align:start position:0% +that x p is given by x prime p is given +by x p minus v the velocity relative + + align:start position:0% +by x p minus v the velocity relative + + + align:start position:0% +by x p minus v the velocity relative +velocity + + align:start position:0% +velocity + + + align:start position:0% +velocity +i could put a little label x here + + align:start position:0% +i could put a little label x here + + + align:start position:0% +i could put a little label x here +times t p + + align:start position:0% +times t p + + + align:start position:0% +times t p +and then for the y coordinates and the z + + align:start position:0% +and then for the y coordinates and the z + + + align:start position:0% +and then for the y coordinates and the z +coordinates there's no change + + align:start position:0% +coordinates there's no change + + + align:start position:0% +coordinates there's no change +for the time intuitively you say that + + align:start position:0% +for the time intuitively you say that + + + align:start position:0% +for the time intuitively you say that +just two watches they run with the same + + align:start position:0% +just two watches they run with the same + + + align:start position:0% +just two watches they run with the same +speed + + align:start position:0% +speed + + + align:start position:0% +speed +um meaning that the time in both frames + + align:start position:0% +um meaning that the time in both frames + + + align:start position:0% +um meaning that the time in both frames +for the same events are the same + + align:start position:0% +for the same events are the same + + + align:start position:0% +for the same events are the same +so now i'm asking you if you're watching + + align:start position:0% +so now i'm asking you if you're watching + + + align:start position:0% +so now i'm asking you if you're watching +this video + + align:start position:0% +this video + + + align:start position:0% +this video +um + + align:start position:0% +um + + + align:start position:0% +um +to find the velocity and acceleration it + + align:start position:0% +to find the velocity and acceleration it + + + align:start position:0% +to find the velocity and acceleration it +might be good to stop and just write + + align:start position:0% +might be good to stop and just write + + + align:start position:0% +might be good to stop and just write +this down + + align:start position:0% +this down + + + align:start position:0% +this down +so find the velocity and acceleration of + + align:start position:0% +so find the velocity and acceleration of + + + align:start position:0% +so find the velocity and acceleration of +the s prime of s prime expressed by the + + align:start position:0% +the s prime of s prime expressed by the + + + align:start position:0% +the s prime of s prime expressed by the +s coordinates let's try to do that + + align:start position:0% +s coordinates let's try to do that + + + align:start position:0% +s coordinates let's try to do that +so first we built the derivative + + align:start position:0% +so first we built the derivative + + + align:start position:0% +so first we built the derivative +dx prime dt prime which is our velocity + + align:start position:0% +dx prime dt prime which is our velocity + + + align:start position:0% +dx prime dt prime which is our velocity +that's the velocity of an object in my + + align:start position:0% +that's the velocity of an object in my + + + align:start position:0% +that's the velocity of an object in my +prime frame + + align:start position:0% +prime frame + + + align:start position:0% +prime frame +and that's given by d dt + + align:start position:0% +and that's given by d dt + + + align:start position:0% +and that's given by d dt +i can just + + align:start position:0% +i can just + + + align:start position:0% +i can just +do that here because the times are the + + align:start position:0% +do that here because the times are the + + + align:start position:0% +do that here because the times are the +same + + align:start position:0% +same + + + align:start position:0% +same +um + + align:start position:0% +um + + + align:start position:0% +um +times x minus vt + + align:start position:0% +times x minus vt + + + align:start position:0% +times x minus vt +that's + + align:start position:0% +that's + + + align:start position:0% +that's +x u x the velocity in my s frame minus v + + align:start position:0% +x u x the velocity in my s frame minus v + + + align:start position:0% +x u x the velocity in my s frame minus v +that's really what you expect you just + + align:start position:0% +that's really what you expect you just + + + align:start position:0% +that's really what you expect you just +subtract or add the velocities + + align:start position:0% +subtract or add the velocities + + + align:start position:0% +subtract or add the velocities +if i then build the acceleration i have + + align:start position:0% +if i then build the acceleration i have + + + align:start position:0% +if i then build the acceleration i have +to build the derivative of u x prime + + align:start position:0% +to build the derivative of u x prime + + + align:start position:0% +to build the derivative of u x prime +which is our acceleration + + align:start position:0% +which is our acceleration + + + align:start position:0% +which is our acceleration +in the prime frame + + align:start position:0% +in the prime frame + + + align:start position:0% +in the prime frame +um here again i just do this in x + + align:start position:0% +um here again i just do this in x + + + align:start position:0% +um here again i just do this in x +direction because the solution for the y + + align:start position:0% +direction because the solution for the y + + + align:start position:0% +direction because the solution for the y +direction and z direction by trivial so + + align:start position:0% +direction and z direction by trivial so + + + align:start position:0% +direction and z direction by trivial so +now i find d u x + + align:start position:0% +now i find d u x + + + align:start position:0% +now i find d u x +dt minus dv dt + + align:start position:0% +dt minus dv dt + + + align:start position:0% +dt minus dv dt +now the velocity as we defined between + + align:start position:0% +now the velocity as we defined between + + + align:start position:0% +now the velocity as we defined between +the two reference frame is constant + + align:start position:0% +the two reference frame is constant + + + align:start position:0% +the two reference frame is constant +therefore this is zero meaning that the + + align:start position:0% +therefore this is zero meaning that the + + + align:start position:0% +therefore this is zero meaning that the +velocity of the accelerations in the two + + align:start position:0% +velocity of the accelerations in the two + + + align:start position:0% +velocity of the accelerations in the two +frames are the same + + align:start position:0% +frames are the same + + + align:start position:0% +frames are the same +the accelerations are the same + + align:start position:0% +the accelerations are the same + + + align:start position:0% +the accelerations are the same +that means that + + align:start position:0% +that means that + + + align:start position:0% +that means that +the uh forces in the two frames are the + + align:start position:0% +the uh forces in the two frames are the + + + align:start position:0% +the uh forces in the two frames are the +same and that means that the forces + + align:start position:0% +same and that means that the forces + + + align:start position:0% +same and that means that the forces +or the accelerations are invariant they + + align:start position:0% +or the accelerations are invariant they + + + align:start position:0% +or the accelerations are invariant they +do not change + + align:start position:0% +do not change + + + align:start position:0% +do not change +based on the reference frame i use + + align:start position:0% +based on the reference frame i use + + + align:start position:0% +based on the reference frame i use +so now + + align:start position:0% +so now + + + align:start position:0% +so now +coming back to the example we discussed + + align:start position:0% +coming back to the example we discussed + + + align:start position:0% +coming back to the example we discussed +in our very first lecture + + align:start position:0% +in our very first lecture + + + align:start position:0% +in our very first lecture +uh your experiment in the train car + + align:start position:0% +uh your experiment in the train car + + + align:start position:0% +uh your experiment in the train car +as + + align:start position:0% + + + + align:start position:0% + +the velocity + + align:start position:0% +the velocity + + + align:start position:0% +the velocity +between those two frames + + align:start position:0% +between those two frames + + + align:start position:0% +between those two frames +the frame + + align:start position:0% +the frame + + + align:start position:0% +the frame +in your car + + align:start position:0% +in your car + + + align:start position:0% +in your car +or a second frame + + align:start position:0% +or a second frame + + + align:start position:0% +or a second frame +are constant there is no way to tell + + align:start position:0% +are constant there is no way to tell + + + align:start position:0% +are constant there is no way to tell +whether or not your train car is moving + + align:start position:0% +whether or not your train car is moving + + + align:start position:0% +whether or not your train car is moving +or not + + align:start position:0% +or not + + + align:start position:0% +or not +that is only true as long as the + + align:start position:0% +that is only true as long as the + + + align:start position:0% +that is only true as long as the +velocities are constant and and and + + align:start position:0% +velocities are constant and and and + + + align:start position:0% +velocities are constant and and and +unchanged constantly + + align:start position:0% +unchanged constantly + + + align:start position:0% +unchanged constantly +so in summary + + align:start position:0% +so in summary + + + align:start position:0% +so in summary +in newton's mechanics time + + align:start position:0% +in newton's mechanics time + + + align:start position:0% +in newton's mechanics time +and accelerations are invariant and + + align:start position:0% +and accelerations are invariant and + + + align:start position:0% +and accelerations are invariant and +therefore also the forces there is no + + align:start position:0% +therefore also the forces there is no + + + align:start position:0% +therefore also the forces there is no +inertial frame which is above another + + align:start position:0% +inertial frame which is above another + + + align:start position:0% +inertial frame which is above another +one + + align:start position:0% +one + + + align:start position:0% +one +so you can pick one or you can pick + + align:start position:0% +so you can pick one or you can pick + + + align:start position:0% +so you can pick one or you can pick +another one there is no difference in + + align:start position:0% +another one there is no difference in + + + align:start position:0% +another one there is no difference in +the descriptions of the physics between + + align:start position:0% +the descriptions of the physics between + + + align:start position:0% +the descriptions of the physics between +those two frames \ No newline at end of file diff --git a/Y9r9dO7KQj4.txt b/Y9r9dO7KQj4.txt new file mode 100644 index 0000000000000000000000000000000000000000..b31699f014d59dfbe0988a91a9acbdaac1908949 --- /dev/null +++ b/Y9r9dO7KQj4.txt @@ -0,0 +1,834 @@ +PROFESSOR: Hi. + +Today I'd like to talk to you +about some notable aspects of + +Python that you'll encounter in +the 6.01 software, as well + +as in the general sense when +working with Python. + +A lot of these little tidbits +of Python have some + +interesting history associated +with them, especially related + +to the history of computer +science. + +And also, I want to indicate +some things that tend to mess + +up, especially, first time +programmers, but also + +especially people that +are new to Python. + +First, I'd like to bring +us back to last week. + +We were talking about +object-oriented programming + +and inheritance. + +Object-oriented programming +is a programming paradigm. + +It's in the same category as +imperative programming or + +functional programming. + +And you might say I have a good +sense of the fact that in + +object-oriented programming, +everything is an object. + +But I don't really have a good +sense of what constitutes + +imperative programming or +functional programming. + +I'm going to focus on functional +programming right + +now, because it has more of a +historic root in the academic + +development of computer +science. + +Functional programming is like +object-oriented programming in + +that everything is a function. + +It refers to the idea that you +want to write as much of your + +code as possible in a purely +functional manner. + +And in particular, you're +looking for the ability to + +avoid things like side-effects +or enable many different kinds + +of evaluation. + +Those kinds of things are not +the subject of this course, + +but I think they're worth noting +to figure out why we're + +bothering learning about things +like lambdas and list + +comprehensions in +the first place. + +Speaking of which, the first +thing we need to talk about + +before we even talk about things +like lambdas and list + +comprehensions, is the concept +that in Python, + +everything is an object. + +But because functions are +first-class objects, we can + +also treat Python to a large +extent like a functional + +programming language. + +What do I mean when +I say functions + +are first class objects? + +I mean that a function +can be the return + +value of another function. + +I mean that the function can be +passed in as an argument to + +a function. + +And I mean that functions can be +assigned variable names and + +manipulated the same way that we +manipulate any other piece + +of data structure. + +This is important, because +if you want higher order + +functions or functions that +actually modify or use other + +functions as a part of you know, +whatever it is they do, + +then you need to be able to +interact with the function + +like it's any other object, +in part pass it in + +or return it out. + +Let's look at an example. + +So let's say I start off with a +very basic function, right? + +If you want to square some +sort of value, probably + +numeric in this case, then +all you have to do is + +multiply it by itself. + +Pretty simple. + +Good place to start. + +As a consequence of the idea +that functions are first class + +objects, I can write a function +that takes in a + +function as an argument and +then develops a return + +function that uses the +function that I + +passed in, on itself. + +So any arguments that I would +pass to someFunction, I would + +pass into someFunction, take +the return value of this + +function call, and then pass +that into someFunction again. + +That's what returnFunction +does. + +And down here, I return +returnFunction. + +Note that the object +type of this + +return value is a function. + +So once I have returnFunction, +I can actually pass it + +arguments, have them run through +someFunction, not once + +but twice, and then get out a +value that's of the return + +type of someFunction. + +Note that I made some +assumptions while + +writing this function. + +First, I've assumed that +someFunction returns out the + +same number of arguments, and +either accept an arbitrary + +number of arguments or accepts +the same number of arguments + +as it puts out. + +The other assumption that I've +made is that the data type + +that someFunction returns is +the same as the data types + +that someFunction accepts. + +Or the things that someFunction +does to its + +arguments can be done to +multiple kinds of arguments. + +But that's a whole different +argument. + +Right now, we're just focusing +on the fact that we pass in + +some arbitrary number of +arguments, call someFunction + +on it, call someFunction again +on the return value of this, + +and return that as something you +can do to whatever it is, + +someFunction operates on. + +OK. + +Let's review an example, because +I promise it'll be + +more clear. + +Let's say f is going to be the + +composition, a square on itself. + +If I do that, I end up with a +function that operates on an + +arbitrary number +of arguments-- + +that's not true. + +I end up with a copy of square +that takes in the same number + +of arguments as square +called on itself. + +So here a square is substituted +for someFunction. + +Here a square is called on +that call of square. + +And here is what f +is assigned to. + +So when I call f of +2, I'm going to + +substitute 2 in for args. + +I'm going to call +square on args. + +If I call square on +args, I get out 4. + +And if I call square on args +again, or if I call square of + +args where args is defined as +the return value of this, then + +I'm going to call square +on 4, I'll square 4, + +and I'll get 16. + +Take a second to type it into +IDLE, and make it make sense + +to yourself. + +All of this code +should compile. + +Mess around with the parameters, +if you're having + +trouble convincing yourself +that it does. + +Ok. + +Now I think we're ready +to talk about lambdas. + +If you can pass in functions as +arguments or return them as + +values or assign them to +variable names and just treat + +them like any other data type, +then you should be able to + +treat them as some sort +of raw value. + +And that's where lambdas +come in. + +Lambda is a key word in Python +that tells you you're about to + +use a function that you have not +given any sort of name or + +defined in any place in your +code or environment + +beforehand. + +You're just going to start +talking about something that + +you would like to do to a given +number of arguments, and + +then what you want +to return out. + +Lambda has roots in lambda +calculus which, if you're + +familiar with the history of +computer science, you've + +probably heard of. + +Now might be a good time to look +up lambda calculus, if + +you've never heard it before +or possibly Alonzo Church. + +But it's still available in code +today, which is really + +cool, and speaks to the +continuing power or at least + +recognition of importance of +functional programming. + +As I said before, the idea with +lambda is that you could + +write an anonymous function. + +Over here, in order to write a +function that's squared, I had + +to write out a define line. + +And because Python uses +indentation, because in + +Python, indentation carries +meaning, I'd have to enter and + +return over to a next line-- + +I'm actually not sure if +that's strictly true. + +I think you can do def +square x, return + +x, but I'm not positive. + +I've only seen it written +like this. + +And I think it's because in the +general sense, people try + +to respect things like +convention and + +readability in Python. + +If you're using lambda, people +already know that you want to + +describe a function +really quickly. + +Or you want to describe +function without + +assigning it any name. + +Therefore, the two most common +uses you'll see of lambda is + +when you want a really fast +function and you don't want to + +spend extra time or lines +writing out that function. + +It's pretty clear what +this is going to do. + +Or if, in a particular +sense, you need + +an anonymous function. + +You don't want to assign +a name or memory space + +associated with that function. + +Note instead of using square, +I can just write out this. + +So I saved two lines of +code defining square. + +And then I don't have to refer +back to some earlier part of + +the code in order to understand + +what this line does. + +Pretty cool. + +All right. + +So there's functions of +first class objects. + +There's lambda. + +Let's talk about how to +use lambdas on lists. + +In Python, you'll end up doing +a lot of list manipulation. + +One of the best uses of +anonymized functions in any + +functional programming language +is the ability to + +manipulate lists in a line. + +If I've defined just a pretty +straightforward list right + +here, I can use functions like +map filter and reduce to-- + +in one line-- + +take a list, apply a function to +every element in that list, + +and then return a copy of +the result of that list. + +I didn't have to write a +separate function to do the + +list handling. + +I didn't have to write a +separate function to multiply + +the list by two. + +And I've communicated what I'm +doing effectively to people + +that are used to functional +programming. + +So if you type this line in, +you should end up with a + +return in interactive mode of +every element in this list + +multiplied by two. + +Now's a good time to try. + +Once you've done that, I also +recommend looking at the + +original copied demolist. + +Note that this is unaltered. + +Map actually returned a new data +structure that represents + +performing this function +on this list. + +This becomes important later +when I explain aliasing, but I + +will do that in about +two minutes. + +If we want to get even more +elegant, we can use list + +comprehensions. + +List comprehensions-- + +if you ask somebody where list +comprehensions are from, + +they'll probably say Haskell, +because that is the most + +popular use of list +comprehensions, in terms of + +pure lazy functional +programming. + +But it actually goes back +further than that, and is in + +Small Talk, and then something +from the '60s. + +I can't remember the name +of it right now. + +They're really nice because +they borrow a syntactic + +approach from mathematicians. + +This looks a lot like +set notation. + +And when you read this, you +can probably tell that the + +list listComprehension is going +to describe a set of + +points from 1 to 4. + +But you accomplish that in +possibly one line of code. + +I've written it on three here +because I wanted to keep it in + +this space. + +But it's really concise. + +If you type this into IDLE, +you should see the kind of + +list that it returns, +and also what's + +listComprehension is now-- + +what now constitutes +listComprehension. + +You can use listComprehensions +with functions like map and + +filter and reduce. + +And, along with the anonymized +functions, all of these tools + +provide you with a lot of +functionality in a very short + +amount of space. + +It's also good to be able to +recognize what's going on when + +you see something like this +or something like this. + +Because you'll probably run into +it in, in particular, a + +lot with Lisp code, but also in +the artificial intelligence + +community in particular. + +Ok. + +We've talked about all that. + +Let's take a second to talk +about the fact that lists are + +actually mutable, and what that +means, and what things + +you have to be careful about if +you're going to be working + +with mutable objects. + +If you're new to programming, +or you're new to Python, + +you've probably already +worked with some of + +these data types, right? + +Any numbers, any strings, +any tuples, + +are going to be immutable. + +What that means is if you have +a variable and you have a + +second variable that has a +different assignment line + +associated with it-- right? + +I haven't assigned +g to h here. + +I've just signed g to "hello" +and h to "hello." + +If you look at the space in +memory that Python associates + +with both objects, they point +to the same place. + +This is the definition of +an immutable object. + +When g points to "hello" and h +points to "hello," they both + +point to the same place. + +If x points to 5 and y points to +5, they're both pointing to + +the same place. + +If you point x at 6, +it now points to a + +different memory address. + +This gets confounded +when you're talking + +about mutable objects. + +The problem with mutable objects +is that you select a + +memory space to contain the +object or memory ID in Python + +to contain the object. + +And then that object is +changed in place. + +You can use this to your +advantage but it can + +also mess with you. + +And here's how. + +Let's say I assigned +a to a small list. + +And I also assigned b to a. + +b and a now point at +the same place. + +If I manipulate b, and I'm-- + +excuse me-- still working with +an immutable object, or excuse + +me, if I'm still working with +a mutable object, the object + +in that memory address +has been altered. + +And b and a still point to +the same place in memory. + +So if I look at a, it's going to +look like b, which is going + +to look like 1, 2, 3, 4 -- + +which is not what I assigned +a to originally. + +Again, can be powerful, but you +have to keep it in mind. + +And it might start to mess with, +in particular, the 6.01 + +software when you're dealing +with state machines. + +In order to get around this, you +can create a copy of the + +list and then modify the copy. + +This is actually +what map does. + +If you want to do it, the +easiest way to do it on the + +first layer is to specify +the index into the + +list with no bounce. + +It'll copy the whole thing. + +There's also a Python library +copy or deep copy, if you want + +to copy lists of lists of +lists of lists of lists. + +And just to clarify, you'll note +that after you assign c + +to a copy of a, c and a occupy +different memory places. + +So if you modify c, a will +retain its original value. + +I think that's all the +notable things I have + +to say about Python. + +and gives us enough power to do +some really powerful list + +manipulation or array +manipulation, and covers what + +we want to say about functional +programming before + +we get into the notion +of state, which I'll + +talk about next time. \ No newline at end of file diff --git a/YS-o3X0tazU.txt b/YS-o3X0tazU.txt new file mode 100644 index 0000000000000000000000000000000000000000..bfd9657975a4b8a46d53267a2fb20f11be88ebb2 --- /dev/null +++ b/YS-o3X0tazU.txt @@ -0,0 +1,987 @@ +align:start position:0% + +okay very briefly I sports a project we + + align:start position:0% +okay very briefly I sports a project we + + + align:start position:0% +okay very briefly I sports a project we +are doing it the sensible City lab but + + align:start position:0% +are doing it the sensible City lab but + + + align:start position:0% +are doing it the sensible City lab but +let me tell you a couple words about + + align:start position:0% +let me tell you a couple words about + + + align:start position:0% +let me tell you a couple words about +sensible city lab it's a new research + + align:start position:0% +sensible city lab it's a new research + + + align:start position:0% +sensible city lab it's a new research +group here at MIT it's in between the + + align:start position:0% +group here at MIT it's in between the + + + align:start position:0% +group here at MIT it's in between the +media lab and urban tourism planning + + align:start position:0% +media lab and urban tourism planning + + + align:start position:0% +media lab and urban tourism planning +well what do we do there what we do is a + + align:start position:0% +well what do we do there what we do is a + + + align:start position:0% +well what do we do there what we do is a +look at this that's that's yesterday's + + align:start position:0% +look at this that's that's yesterday's + + + align:start position:0% +look at this that's that's yesterday's +wireless that's varco knees Cape Cod + + align:start position:0% +wireless that's varco knees Cape Cod + + + align:start position:0% +wireless that's varco knees Cape Cod +station look at all of that steel and + + align:start position:0% +station look at all of that steel and + + + align:start position:0% +station look at all of that steel and +engine and energy and the amount of + + align:start position:0% +engine and energy and the amount of + + + align:start position:0% +engine and energy and the amount of +effort just to transmit a few bits of + + align:start position:0% +effort just to transmit a few bits of + + + align:start position:0% +effort just to transmit a few bits of +information across the Atlantic now look + + align:start position:0% +information across the Atlantic now look + + + align:start position:0% +information across the Atlantic now look +at today's wireless it's more like this + + align:start position:0% +at today's wireless it's more like this + + + align:start position:0% +at today's wireless it's more like this +and you can actually transmit much more + + align:start position:0% +and you can actually transmit much more + + + align:start position:0% +and you can actually transmit much more +information using that and what we're + + align:start position:0% +information using that and what we're + + + align:start position:0% +information using that and what we're +doing is sort of we think in a creative + + align:start position:0% +doing is sort of we think in a creative + + + align:start position:0% +doing is sort of we think in a creative +way the interface between people mobile + + align:start position:0% +way the interface between people mobile + + + align:start position:0% +way the interface between people mobile +technology and the city now concerning I + + align:start position:0% +technology and the city now concerning I + + + align:start position:0% +technology and the city now concerning I +spots this project is based on the MIT + + align:start position:0% +spots this project is based on the MIT + + + align:start position:0% +spots this project is based on the MIT +campus that's what you see there so you + + align:start position:0% +campus that's what you see there so you + + + align:start position:0% +campus that's what you see there so you +most of you I'm sure familiar Bob stone + + align:start position:0% +most of you I'm sure familiar Bob stone + + + align:start position:0% +most of you I'm sure familiar Bob stone +MIT and the interesting thing is that if + + align:start position:0% +MIT and the interesting thing is that if + + + align:start position:0% +MIT and the interesting thing is that if +you talk to anybody at MIT they will + + align:start position:0% +you talk to anybody at MIT they will + + + align:start position:0% +you talk to anybody at MIT they will +tell you there's a big revolution + + align:start position:0% +tell you there's a big revolution + + + align:start position:0% +tell you there's a big revolution +happening and this revolution is in the + + align:start position:0% +happening and this revolution is in the + + + align:start position:0% +happening and this revolution is in the +way people live and work and it's + + align:start position:0% +way people live and work and it's + + + align:start position:0% +way people live and work and it's +brought by laptop computers and Wi-Fi so + + align:start position:0% +brought by laptop computers and Wi-Fi so + + + align:start position:0% +brought by laptop computers and Wi-Fi so +if you look at this this is how people + + align:start position:0% +if you look at this this is how people + + + align:start position:0% +if you look at this this is how people +used to work here and this is more like + + align:start position:0% +used to work here and this is more like + + + align:start position:0% +used to work here and this is more like +today now this is a bit biased as you + + align:start position:0% +today now this is a bit biased as you + + + align:start position:0% +today now this is a bit biased as you +see we we could find the worst possible + + align:start position:0% +see we we could find the worst possible + + + align:start position:0% +see we we could find the worst possible +image of a computer room dull boring no + + align:start position:0% +image of a computer room dull boring no + + + align:start position:0% +image of a computer room dull boring no +natural light and and this like a sunny + + align:start position:0% +natural light and and this like a sunny + + + align:start position:0% +natural light and and this like a sunny +day it's not like today but the thing is + + align:start position:0% +day it's not like today but the thing is + + + align:start position:0% +day it's not like today but the thing is +that there's a big change and what we + + align:start position:0% +that there's a big change and what we + + + align:start position:0% +that there's a big change and what we +are trying to do with I sports is try to + + align:start position:0% +are trying to do with I sports is try to + + + align:start position:0% +are trying to do with I sports is try to +define and see how the change is + + align:start position:0% +define and see how the change is + + + align:start position:0% +define and see how the change is +happening and quantify this by allowing + + align:start position:0% +happening and quantify this by allowing + + + align:start position:0% +happening and quantify this by allowing +people to locate themselves actually + + align:start position:0% +people to locate themselves actually + + + align:start position:0% +people to locate themselves actually +with a few meter accuracy using the + + align:start position:0% +with a few meter accuracy using the + + + align:start position:0% +with a few meter accuracy using the +Wi-Fi network and so it's a unique case + + align:start position:0% +Wi-Fi network and so it's a unique case + + + align:start position:0% +Wi-Fi network and so it's a unique case +study that you are starting to monitor + + align:start position:0% +study that you are starting to monitor + + + align:start position:0% +study that you are starting to monitor +where we got 20,000 people in the MIT + + align:start position:0% +where we got 20,000 people in the MIT + + + align:start position:0% +where we got 20,000 people in the MIT +campus a big chunk urban chunk with + + align:start position:0% +campus a big chunk urban chunk with + + + align:start position:0% +campus a big chunk urban chunk with +3,000 access points that's quite a bit + + align:start position:0% +3,000 access points that's quite a bit + + + align:start position:0% +3,000 access points that's quite a bit +if you think that cities like + + align:start position:0% +if you think that cities like + + + align:start position:0% +if you think that cities like +Philadelphia actually are planning to + + align:start position:0% +Philadelphia actually are planning to + + + align:start position:0% +Philadelphia actually are planning to +cover all of this + + align:start position:0% +cover all of this + + + align:start position:0% +cover all of this +with Wi-Fi in the can in the next couple + + align:start position:0% +with Wi-Fi in the can in the next couple + + + align:start position:0% +with Wi-Fi in the can in the next couple +of years and that's less than three + + align:start position:0% +of years and that's less than three + + + align:start position:0% +of years and that's less than three +thousand less than the number we have of + + align:start position:0% +thousand less than the number we have of + + + align:start position:0% +thousand less than the number we have of +access point this high density means + + align:start position:0% +access point this high density means + + + align:start position:0% +access point this high density means +that we can locate everybody with just a + + align:start position:0% +that we can locate everybody with just a + + + align:start position:0% +that we can locate everybody with just a +few meters accuracy this is just a map + + align:start position:0% +few meters accuracy this is just a map + + + align:start position:0% +few meters accuracy this is just a map +with some of the access points and + + align:start position:0% +with some of the access points and + + + align:start position:0% +with some of the access points and +actually i'll show you the two marks for + + align:start position:0% +actually i'll show you the two marks for + + + align:start position:0% +actually i'll show you the two marks for +for the project you'll see at the museum + + align:start position:0% + + + + align:start position:0% + +oops the first type of map is a map that + + align:start position:0% +oops the first type of map is a map that + + + align:start position:0% +oops the first type of map is a map that +shows you in real time the activity + + align:start position:0% +shows you in real time the activity + + + align:start position:0% +shows you in real time the activity +going on on the network and how many + + align:start position:0% +going on on the network and how many + + + align:start position:0% +going on on the network and how many +people are working in different parts of + + align:start position:0% +people are working in different parts of + + + align:start position:0% +people are working in different parts of +the campus so you get this type of map + + align:start position:0% +the campus so you get this type of map + + + align:start position:0% +the campus so you get this type of map +changing you don't see very well here + + align:start position:0% +changing you don't see very well here + + + align:start position:0% +changing you don't see very well here +but you see better the museum and the + + align:start position:0% +but you see better the museum and the + + + align:start position:0% +but you see better the museum and the +second map is this one that's like oops + + align:start position:0% + + + + align:start position:0% + +that's like the heartbeat of MIT now + + align:start position:0% +that's like the heartbeat of MIT now + + + align:start position:0% +that's like the heartbeat of MIT now +what you see here is total activity + + align:start position:0% +what you see here is total activity + + + align:start position:0% +what you see here is total activity +going on on the campus in real time and + + align:start position:0% +going on on the campus in real time and + + + align:start position:0% +going on on the campus in real time and +you see the past week so what you see + + align:start position:0% +you see the past week so what you see + + + align:start position:0% +you see the past week so what you see +here is all of MIT and that's actually a + + align:start position:0% +here is all of MIT and that's actually a + + + align:start position:0% +here is all of MIT and that's actually a +standard day you see people come in + + align:start position:0% +standard day you see people come in + + + align:start position:0% +standard day you see people come in +working nine to five and then actually + + align:start position:0% +working nine to five and then actually + + + align:start position:0% +working nine to five and then actually +students keeping them working quite late + + align:start position:0% +students keeping them working quite late + + + align:start position:0% +students keeping them working quite late +even even during iap and then you got a + + align:start position:0% +even even during iap and then you got a + + + align:start position:0% +even even during iap and then you got a +peek a peek and a minimum at 6am and + + align:start position:0% +peek a peek and a minimum at 6am and + + + align:start position:0% +peek a peek and a minimum at 6am and +then you got the next day it's + + align:start position:0% +then you got the next day it's + + + align:start position:0% +then you got the next day it's +interesting Friday Saturday and Sunday + + align:start position:0% +interesting Friday Saturday and Sunday + + + align:start position:0% +interesting Friday Saturday and Sunday +when most of the activity 925 activity + + align:start position:0% +when most of the activity 925 activity + + + align:start position:0% +when most of the activity 925 activity +disappears and actually you got just the + + align:start position:0% +disappears and actually you got just the + + + align:start position:0% +disappears and actually you got just the +remaining part of the curve happening + + align:start position:0% +remaining part of the curve happening + + + align:start position:0% +remaining part of the curve happening +activity is sweeping down in on friday + + align:start position:0% +activity is sweeping down in on friday + + + align:start position:0% +activity is sweeping down in on friday +evening people going out and on sunday + + align:start position:0% +evening people going out and on sunday + + + align:start position:0% +evening people going out and on sunday +when you're starting to panic again + + align:start position:0% +when you're starting to panic again + + + align:start position:0% +when you're starting to panic again +about monday in the next week then + + align:start position:0% +about monday in the next week then + + + align:start position:0% +about monday in the next week then +there's another peak and then what you + + align:start position:0% +there's another peak and then what you + + + align:start position:0% +there's another peak and then what you +see here you can do this in cui every + + align:start position:0% +see here you can do this in cui every + + + align:start position:0% +see here you can do this in cui every +room on the campus and what you see here + + align:start position:0% +room on the campus and what you see here + + + align:start position:0% +room on the campus and what you see here +for instance is this actual room and you + + align:start position:0% +for instance is this actual room and you + + + align:start position:0% +for instance is this actual room and you +see most of the week it was pretty no + + align:start position:0% +see most of the week it was pretty no + + + align:start position:0% +see most of the week it was pretty no +activity and look at today and today you + + align:start position:0% +activity and look at today and today you + + + align:start position:0% +activity and look at today and today you +can get that you get actually up to 25 + + align:start position:0% +can get that you get actually up to 25 + + + align:start position:0% +can get that you get actually up to 25 +users which is the number of laptop i + + align:start position:0% +users which is the number of laptop i + + + align:start position:0% +users which is the number of laptop i +counted + + align:start position:0% +counted + + + align:start position:0% +counted +accounted earlier today of people + + align:start position:0% +accounted earlier today of people + + + align:start position:0% +accounted earlier today of people +connected to the wireless internet here + + align:start position:0% +connected to the wireless internet here + + + align:start position:0% +connected to the wireless internet here +and you sit here that's today Monday it + + align:start position:0% +and you sit here that's today Monday it + + + align:start position:0% +and you sit here that's today Monday it +will appear in a minute anyway you see + + align:start position:0% +will appear in a minute anyway you see + + + align:start position:0% +will appear in a minute anyway you see +the demo at yeah here you see the spike + + align:start position:0% +the demo at yeah here you see the spike + + + align:start position:0% +the demo at yeah here you see the spike +today today's activity and you see the + + align:start position:0% +today today's activity and you see the + + + align:start position:0% +today today's activity and you see the +demo at the museum just a couple of just + + align:start position:0% +demo at the museum just a couple of just + + + align:start position:0% +demo at the museum just a couple of just +a couple of things about just to + + align:start position:0% +a couple of things about just to + + + align:start position:0% +a couple of things about just to +conclude another project we have is + + align:start position:0% +conclude another project we have is + + + align:start position:0% +conclude another project we have is +actually with with a soccer team being + + align:start position:0% +actually with with a soccer team being + + + align:start position:0% +actually with with a soccer team being +Italian I am very proud of this project + + align:start position:0% +Italian I am very proud of this project + + + align:start position:0% +Italian I am very proud of this project +and it's with AC Milan and he were + + align:start position:0% +and it's with AC Milan and he were + + + align:start position:0% +and it's with AC Milan and he were +tracking actually players with a couple + + align:start position:0% +tracking actually players with a couple + + + align:start position:0% +tracking actually players with a couple +of centimeter accuracy in real time and + + align:start position:0% +of centimeter accuracy in real time and + + + align:start position:0% +of centimeter accuracy in real time and +then developing artificial intelligence + + align:start position:0% +then developing artificial intelligence + + + align:start position:0% +then developing artificial intelligence +algorithms in order to study the + + align:start position:0% +algorithms in order to study the + + + align:start position:0% +algorithms in order to study the +movement and optimize strategy so we get + + align:start position:0% +movement and optimize strategy so we get + + + align:start position:0% +movement and optimize strategy so we get +this type of traces and then analyze + + align:start position:0% +this type of traces and then analyze + + + align:start position:0% +this type of traces and then analyze +them and then because a number of other + + align:start position:0% +them and then because a number of other + + + align:start position:0% +them and then because a number of other +projects really dealing with technology + + align:start position:0% +projects really dealing with technology + + + align:start position:0% +projects really dealing with technology +and space how technology in space + + align:start position:0% +and space how technology in space + + + align:start position:0% +and space how technology in space +interface we also started this is funded + + align:start position:0% +interface we also started this is funded + + + align:start position:0% +interface we also started this is funded +through a sensible City consortium + + align:start position:0% +through a sensible City consortium + + + align:start position:0% +through a sensible City consortium +that's sort of bringing together the + + align:start position:0% +that's sort of bringing together the + + + align:start position:0% +that's sort of bringing together the +different the key actors being part of + + align:start position:0% +different the key actors being part of + + + align:start position:0% +different the key actors being part of +this revolution from network operators + + align:start position:0% +this revolution from network operators + + + align:start position:0% +this revolution from network operators +hardware companies urban hardware and in + + align:start position:0% +hardware companies urban hardware and in + + + align:start position:0% +hardware companies urban hardware and in +public administration but that's it i + + align:start position:0% +public administration but that's it i + + + align:start position:0% +public administration but that's it i +think if you dry to have a chat will be + + align:start position:0% +think if you dry to have a chat will be + + + align:start position:0% +think if you dry to have a chat will be +at the museum thanks a lot \ No newline at end of file diff --git a/YzZUIYRCE38.txt b/YzZUIYRCE38.txt new file mode 100644 index 0000000000000000000000000000000000000000..a4aae501f207b2aaf4fc5e70624845bfe5d54697 --- /dev/null +++ b/YzZUIYRCE38.txt @@ -0,0 +1,7253 @@ +align:start position:0% + +okay uh cameras are rolling this is + + align:start position:0% +okay uh cameras are rolling this is + + + align:start position:0% +okay uh cameras are rolling this is +lecture + + align:start position:0% +lecture + + + align:start position:0% +lecture +14 starting a new + + align:start position:0% +14 starting a new + + + align:start position:0% +14 starting a new +chapter chapter about + + align:start position:0% +chapter chapter about + + + align:start position:0% +chapter chapter about +orthogonality what it means for vectors + + align:start position:0% +orthogonality what it means for vectors + + + align:start position:0% +orthogonality what it means for vectors +to be + + align:start position:0% +to be + + + align:start position:0% +to be +orthogonal what it means for subspaces + + align:start position:0% +orthogonal what it means for subspaces + + + align:start position:0% +orthogonal what it means for subspaces +to be orthogonal what it means for bases + + align:start position:0% +to be orthogonal what it means for bases + + + align:start position:0% +to be orthogonal what it means for bases +to be + + align:start position:0% +to be + + + align:start position:0% +to be +orthogonal so 90° this is a this is a 90 + + align:start position:0% +orthogonal so 90° this is a this is a 90 + + + align:start position:0% +orthogonal so 90° this is a this is a 90 +Dee + + align:start position:0% +Dee + + + align:start position:0% +Dee +chapter so what does it + + align:start position:0% +chapter so what does it + + + align:start position:0% +chapter so what does it +mean uh let me let me jump to + + align:start position:0% +mean uh let me let me jump to + + + align:start position:0% +mean uh let me let me jump to +subspaces because I've drawn here the + + align:start position:0% +subspaces because I've drawn here the + + + align:start position:0% +subspaces because I've drawn here the +big picture this is the this is the 1806 + + align:start position:0% +big picture this is the this is the 1806 + + + align:start position:0% +big picture this is the this is the 1806 +picture here and and uh hold it down + + align:start position:0% +picture here and and uh hold it down + + + align:start position:0% +picture here and and uh hold it down +guys uh so this is the picture and we + + align:start position:0% +guys uh so this is the picture and we + + + align:start position:0% +guys uh so this is the picture and we +know a lot about that picture already we + + align:start position:0% +know a lot about that picture already we + + + align:start position:0% +know a lot about that picture already we +know the dimension of every Subspace we + + align:start position:0% +know the dimension of every Subspace we + + + align:start position:0% +know the dimension of every Subspace we +know that these dimensions + + align:start position:0% +know that these dimensions + + + align:start position:0% +know that these dimensions +are R and N minus r we know that these + + align:start position:0% +are R and N minus r we know that these + + + align:start position:0% +are R and N minus r we know that these +dimensions are R and M minus + + align:start position:0% +dimensions are R and M minus + + + align:start position:0% +dimensions are R and M minus +r what we what I want to show now is + + align:start position:0% +r what we what I want to show now is + + + align:start position:0% +r what we what I want to show now is +what this figure is saying that the + + align:start position:0% +what this figure is saying that the + + + align:start position:0% +what this figure is saying that the +angle with the figure is like just my + + align:start position:0% +angle with the figure is like just my + + + align:start position:0% +angle with the figure is like just my +attempt to draw what I'm now going to + + align:start position:0% +attempt to draw what I'm now going to + + + align:start position:0% +attempt to draw what I'm now going to +say that the angle between these + + align:start position:0% +say that the angle between these + + + align:start position:0% +say that the angle between these +subspaces is + + align:start position:0% +subspaces is + + + align:start position:0% +subspaces is +90° and the angle between these + + align:start position:0% +90° and the angle between these + + + align:start position:0% +90° and the angle between these +subspaces is 90° now I have to say what + + align:start position:0% +subspaces is 90° now I have to say what + + + align:start position:0% +subspaces is 90° now I have to say what +does that mean what does it mean for + + align:start position:0% +does that mean what does it mean for + + + align:start position:0% +does that mean what does it mean for +subspaces to be orthogonal + + align:start position:0% +subspaces to be orthogonal + + + align:start position:0% +subspaces to be orthogonal +but I hope you appreciate + + align:start position:0% +but I hope you appreciate + + + align:start position:0% +but I hope you appreciate +the beauty of this + + align:start position:0% +the beauty of this + + + align:start position:0% +the beauty of this +picture that that those subspaces are + + align:start position:0% +picture that that those subspaces are + + + align:start position:0% +picture that that those subspaces are +going to come out to be + + align:start position:0% +going to come out to be + + + align:start position:0% +going to come out to be +orthogonal those two and also those two + + align:start position:0% +orthogonal those two and also those two + + + align:start position:0% +orthogonal those two and also those two +so that's like one + + align:start position:0% +so that's like one + + + align:start position:0% +so that's like one +point one important point to step + + align:start position:0% +point one important point to step + + + align:start position:0% +point one important point to step +forward in understanding those subspaces + + align:start position:0% +forward in understanding those subspaces + + + align:start position:0% +forward in understanding those subspaces +we knew what each Subspace was like we + + align:start position:0% +we knew what each Subspace was like we + + + align:start position:0% +we knew what each Subspace was like we +could compute bases for them now we know + + align:start position:0% +could compute bases for them now we know + + + align:start position:0% +could compute bases for them now we know +more or we will in a few + + align:start position:0% +more or we will in a few + + + align:start position:0% +more or we will in a few +minutes okay I have to say first of all + + align:start position:0% +minutes okay I have to say first of all + + + align:start position:0% +minutes okay I have to say first of all +what does it mean for two vectors to be + + align:start position:0% +what does it mean for two vectors to be + + + align:start position:0% +what does it mean for two vectors to be +orthogonal so let me start with + + align:start position:0% + + + + align:start position:0% + +that orthogonal + + align:start position:0% + + + + align:start position:0% + +vectors the word orthogonal is is just + + align:start position:0% +vectors the word orthogonal is is just + + + align:start position:0% +vectors the word orthogonal is is just +just another word for + + align:start position:0% +just another word for + + + align:start position:0% +just another word for +perpendicular it means that in N + + align:start position:0% +perpendicular it means that in N + + + align:start position:0% +perpendicular it means that in N +dimensional space the angle between + + align:start position:0% +dimensional space the angle between + + + align:start position:0% +dimensional space the angle between +those vectors is + + align:start position:0% +those vectors is + + + align:start position:0% +those vectors is +90° it means that they form a right + + align:start position:0% +90° it means that they form a right + + + align:start position:0% +90° it means that they form a right +triangle it even means that the going + + align:start position:0% +triangle it even means that the going + + + align:start position:0% +triangle it even means that the going +way back to the Greeks that this uh + + align:start position:0% +way back to the Greeks that this uh + + + align:start position:0% +way back to the Greeks that this uh +angle that this triangle a vector + + align:start position:0% +angle that this triangle a vector + + + align:start position:0% +angle that this triangle a vector +x a vector + + align:start position:0% +x a vector + + + align:start position:0% +x a vector +y and the vector x + y of course that'll + + align:start position:0% +y and the vector x + y of course that'll + + + align:start position:0% +y and the vector x + y of course that'll +be the + + align:start position:0% +be the + + + align:start position:0% +be the +hypotenuse so what was it the Greeks + + align:start position:0% +hypotenuse so what was it the Greeks + + + align:start position:0% +hypotenuse so what was it the Greeks +figured out and it's neat it's the fact + + align:start position:0% +figured out and it's neat it's the fact + + + align:start position:0% +figured out and it's neat it's the fact +that the so these are orthogonal this is + + align:start position:0% +that the so these are orthogonal this is + + + align:start position:0% +that the so these are orthogonal this is +a right angle if so so let me put the + + align:start position:0% +a right angle if so so let me put the + + + align:start position:0% +a right angle if so so let me put the +great name down + + align:start position:0% + + + + align:start position:0% + +Pythagoras I'm I'm looking for what am I + + align:start position:0% +Pythagoras I'm I'm looking for what am I + + + align:start position:0% +Pythagoras I'm I'm looking for what am I +looking for for I'm looking for the + + align:start position:0% +looking for for I'm looking for the + + + align:start position:0% +looking for for I'm looking for the +condition if you give me two vectors how + + align:start position:0% +condition if you give me two vectors how + + + align:start position:0% +condition if you give me two vectors how +do I know if they're + + align:start position:0% +do I know if they're + + + align:start position:0% +do I know if they're +orthogonal how can I tell two + + align:start position:0% +orthogonal how can I tell two + + + align:start position:0% +orthogonal how can I tell two +perpendicular vectors and actually you + + align:start position:0% +perpendicular vectors and actually you + + + align:start position:0% +perpendicular vectors and actually you +probably know the answer let me write + + align:start position:0% +probably know the answer let me write + + + align:start position:0% +probably know the answer let me write +the answer down orthogonal vectors + + align:start position:0% +the answer down orthogonal vectors + + + align:start position:0% +the answer down orthogonal vectors +what's the test for + + align:start position:0% +what's the test for + + + align:start position:0% +what's the test for +orthogonality I take the dotproduct + + align:start position:0% +orthogonality I take the dotproduct + + + align:start position:0% +orthogonality I take the dotproduct +which I tend to write as X transpose y + + align:start position:0% +which I tend to write as X transpose y + + + align:start position:0% +which I tend to write as X transpose y +because that's a row times a column and + + align:start position:0% +because that's a row times a column and + + + align:start position:0% +because that's a row times a column and +that matrix multiplication just gives me + + align:start position:0% +that matrix multiplication just gives me + + + align:start position:0% +that matrix multiplication just gives me +the right thing that X1 y1 plus X2 Y2 + + align:start position:0% +the right thing that X1 y1 plus X2 Y2 + + + align:start position:0% +the right thing that X1 y1 plus X2 Y2 +and so on so these vectors are + + align:start position:0% +and so on so these vectors are + + + align:start position:0% +and so on so these vectors are +orthogonal if + + align:start position:0% +orthogonal if + + + align:start position:0% +orthogonal if +this result X transpose Y + + align:start position:0% +this result X transpose Y + + + align:start position:0% +this result X transpose Y +is zero that's the test okay can I + + align:start position:0% +is zero that's the test okay can I + + + align:start position:0% +is zero that's the test okay can I +connect that to other things + + align:start position:0% +connect that to other things + + + align:start position:0% +connect that to other things +I mean it's like it's amazing it's it's + + align:start position:0% +I mean it's like it's amazing it's it's + + + align:start position:0% +I mean it's like it's amazing it's it's +just beautiful that here we have we're + + align:start position:0% +just beautiful that here we have we're + + + align:start position:0% +just beautiful that here we have we're +in N + + align:start position:0% +in N + + + align:start position:0% +in N +Dimensions we've got a couple of vectors + + align:start position:0% +Dimensions we've got a couple of vectors + + + align:start position:0% +Dimensions we've got a couple of vectors +we want to know the angle between them + + align:start position:0% +we want to know the angle between them + + + align:start position:0% +we want to know the angle between them +and the right thing to look at is the + + align:start position:0% +and the right thing to look at is the + + + align:start position:0% +and the right thing to look at is the +simplest thing you can imagine the dot + + align:start position:0% +simplest thing you can imagine the dot + + + align:start position:0% +simplest thing you can imagine the dot +product okay now why so I'm answering + + align:start position:0% +product okay now why so I'm answering + + + align:start position:0% +product okay now why so I'm answering +the question now why let's just some + + align:start position:0% +the question now why let's just some + + + align:start position:0% +the question now why let's just some +let's add some uh justification to this + + align:start position:0% +let's add some uh justification to this + + + align:start position:0% +let's add some uh justification to this +fact that that's the test okay so + + align:start position:0% +fact that that's the test okay so + + + align:start position:0% +fact that that's the test okay so +Pythagoras would say we've got a right + + align:start position:0% +Pythagoras would say we've got a right + + + align:start position:0% +Pythagoras would say we've got a right +triangle if that length squared plus + + align:start position:0% +triangle if that length squared plus + + + align:start position:0% +triangle if that length squared plus +that length squared equals that length + + align:start position:0% +that length squared equals that length + + + align:start position:0% +that length squared equals that length +squared okay can I write it as + + align:start position:0% +squared okay can I write it as + + + align:start position:0% +squared okay can I write it as +X2 + + + align:start position:0% +X2 + + + + align:start position:0% +X2 + +y^2 + + align:start position:0% +y^2 + + + align:start position:0% +y^2 += x + + + align:start position:0% += x + + + + align:start position:0% += x + +Y2 now don't please don't think that + + align:start position:0% +Y2 now don't please don't think that + + + align:start position:0% +Y2 now don't please don't think that +this is always + + align:start position:0% +this is always + + + align:start position:0% +this is always +true this is only going to be true in + + align:start position:0% +true this is only going to be true in + + + align:start position:0% +true this is only going to be true in +this it's going to be equivalent to + + align:start position:0% +this it's going to be equivalent to + + + align:start position:0% +this it's going to be equivalent to +orthogonality for other triangles of + + align:start position:0% +orthogonality for other triangles of + + + align:start position:0% +orthogonality for other triangles of +course it's not true for other triangles + + align:start position:0% +course it's not true for other triangles + + + align:start position:0% +course it's not true for other triangles +it's not but for a right triangle + + align:start position:0% +it's not but for a right triangle + + + align:start position:0% +it's not but for a right triangle +somehow that fact should connect to that + + align:start position:0% +somehow that fact should connect to that + + + align:start position:0% +somehow that fact should connect to that +fact can we just make that + + align:start position:0% + + + + align:start position:0% + +connection what's the connection between + + align:start position:0% +connection what's the connection between + + + align:start position:0% +connection what's the connection between +this test for orthogonality and this + + align:start position:0% +this test for orthogonality and this + + + align:start position:0% +this test for orthogonality and this +statement of orthogonality well I guess + + align:start position:0% +statement of orthogonality well I guess + + + align:start position:0% +statement of orthogonality well I guess +I have to say what is the length squared + + align:start position:0% +I have to say what is the length squared + + + align:start position:0% +I have to say what is the length squared +so let's continue on the board + + align:start position:0% +so let's continue on the board + + + align:start position:0% +so let's continue on the board +underneath with that equation give me + + align:start position:0% +underneath with that equation give me + + + align:start position:0% +underneath with that equation give me +another way to express the length + + align:start position:0% +another way to express the length + + + align:start position:0% +another way to express the length +squared of a + + align:start position:0% +squared of a + + + align:start position:0% +squared of a +vector let me just give you a vector the + + align:start position:0% +vector let me just give you a vector the + + + align:start position:0% +vector let me just give you a vector the +vector 1 two + + align:start position:0% +vector 1 two + + + align:start position:0% +vector 1 two +3 that's in three + + align:start position:0% +3 that's in three + + + align:start position:0% +3 that's in three +dimensions what is the length squared of + + align:start position:0% +dimensions what is the length squared of + + + align:start position:0% +dimensions what is the length squared of +the vector X equal 1 2 + + align:start position:0% +the vector X equal 1 2 + + + align:start position:0% +the vector X equal 1 2 +3 so how do you find the length + + align:start position:0% +3 so how do you find the length + + + align:start position:0% +3 so how do you find the length +squared well really you're just you want + + align:start position:0% +squared well really you're just you want + + + align:start position:0% +squared well really you're just you want +the length of that Vector that goes + + align:start position:0% +the length of that Vector that goes + + + align:start position:0% +the length of that Vector that goes +along one up two and out three and and + + align:start position:0% +along one up two and out three and and + + + align:start position:0% +along one up two and out three and and +we'll come come back to that right + + align:start position:0% +we'll come come back to that right + + + align:start position:0% +we'll come come back to that right +triangle stuff the length squared is + + align:start position:0% +triangle stuff the length squared is + + + align:start position:0% +triangle stuff the length squared is +this is + + align:start position:0% +this is + + + align:start position:0% +this is +exactly X transpose + + align:start position:0% + + + + align:start position:0% + +X whenever I d x transpose X I know I've + + align:start position:0% +X whenever I d x transpose X I know I've + + + align:start position:0% +X whenever I d x transpose X I know I've +got a number that's positive it's a + + align:start position:0% +got a number that's positive it's a + + + align:start position:0% +got a number that's positive it's a +length squared unless it unless X + + align:start position:0% +length squared unless it unless X + + + align:start position:0% +length squared unless it unless X +happens to be the zero Vector that's the + + align:start position:0% +happens to be the zero Vector that's the + + + align:start position:0% +happens to be the zero Vector that's the +one case where the length is + + align:start position:0% +one case where the length is + + + align:start position:0% +one case where the length is +zero so right this is just X1 2 plus X2 + + align:start position:0% +zero so right this is just X1 2 plus X2 + + + align:start position:0% +zero so right this is just X1 2 plus X2 +2ar plus so on plus xn^ 2 so one in the + + align:start position:0% +2ar plus so on plus xn^ 2 so one in the + + + align:start position:0% +2ar plus so on plus xn^ 2 so one in the +example I gave you what was the length + + align:start position:0% +example I gave you what was the length + + + align:start position:0% +example I gave you what was the length +squar of that Vector 1 2 + + align:start position:0% +squar of that Vector 1 2 + + + align:start position:0% +squar of that Vector 1 2 +3 so so you square those you get 1 4 and + + align:start position:0% +3 so so you square those you get 1 4 and + + + align:start position:0% +3 so so you square those you get 1 4 and +9 you add you get + + align:start position:0% +9 you add you get + + + align:start position:0% +9 you add you get +14 so the vector 1 2 3 has length + + align:start position:0% +14 so the vector 1 2 3 has length + + + align:start position:0% +14 so the vector 1 2 3 has length +14 so let me just let let me just put + + align:start position:0% +14 so let me just let let me just put + + + align:start position:0% +14 so let me just let let me just put +down a vector here uh let X be the + + align:start position:0% +down a vector here uh let X be the + + + align:start position:0% +down a vector here uh let X be the +vector one + + align:start position:0% + + + + align:start position:0% + +23 let me cook up a vector that's + + align:start position:0% +23 let me cook up a vector that's + + + align:start position:0% +23 let me cook up a vector that's +orthogonal to + + align:start position:0% + + + + align:start position:0% + +it so what's the vector that's + + align:start position:0% +it so what's the vector that's + + + align:start position:0% +it so what's the vector that's +orthogonal so write down here + + align:start position:0% +orthogonal so write down here + + + align:start position:0% +orthogonal so write down here +x^2 is 1 + 4 + 9 + + align:start position:0% +x^2 is 1 + 4 + 9 + + + align:start position:0% +x^2 is 1 + 4 + 9 +14 uh let me cook up a vector that's + + align:start position:0% +14 uh let me cook up a vector that's + + + align:start position:0% +14 uh let me cook up a vector that's +orthogonal to it we'll + + align:start position:0% + + + + align:start position:0% + +get right that that those two vectors + + align:start position:0% +get right that that those two vectors + + + align:start position:0% +get right that that those two vectors +are orthogonal the length of y^2 + + align:start position:0% + + + + align:start position:0% + +is + + align:start position:0% +is + + + align:start position:0% +is +5 and x + + + align:start position:0% +5 and x + + + + align:start position:0% +5 and x + +y is is 1 and two making three 2 and Min + + align:start position:0% +y is is 1 and two making three 2 and Min + + + align:start position:0% +y is is 1 and two making three 2 and Min +- one making 1 3 and zero making three + + align:start position:0% +- one making 1 3 and zero making three + + + align:start position:0% +- one making 1 3 and zero making three +and the length of this + + align:start position:0% +and the length of this + + + align:start position:0% +and the length of this +squared is 9 + 1 + 9 + + align:start position:0% +squared is 9 + 1 + 9 + + + align:start position:0% +squared is 9 + 1 + 9 +19 and sure + + align:start position:0% +19 and sure + + + align:start position:0% +19 and sure +enough I I haven't proved anything I'm + + align:start position:0% +enough I I haven't proved anything I'm + + + align:start position:0% +enough I I haven't proved anything I'm +just + + align:start position:0% +just + + + align:start position:0% +just +like check to see that my my my test X + + align:start position:0% +like check to see that my my my test X + + + align:start position:0% +like check to see that my my my test X +transpose y equal 0 which is true right + + align:start position:0% +transpose y equal 0 which is true right + + + align:start position:0% +transpose y equal 0 which is true right +everybody sees that X transpose Y is + + align:start position:0% +everybody sees that X transpose Y is + + + align:start position:0% +everybody sees that X transpose Y is +zero here that that's maybe the main + + align:start position:0% +zero here that that's maybe the main + + + align:start position:0% +zero here that that's maybe the main +point that you should get really quick + + align:start position:0% +point that you should get really quick + + + align:start position:0% +point that you should get really quick +at doing X transpose y so it's just this + + align:start position:0% +at doing X transpose y so it's just this + + + align:start position:0% +at doing X transpose y so it's just this +plus this plus this and that's zero and + + align:start position:0% +plus this plus this and that's zero and + + + align:start position:0% +plus this plus this and that's zero and +sure enough that clicks with uh 14 + 5 + + align:start position:0% +sure enough that clicks with uh 14 + 5 + + + align:start position:0% +sure enough that clicks with uh 14 + 5 +agreeing with 19 now let me just do that + + align:start position:0% +agreeing with 19 now let me just do that + + + align:start position:0% +agreeing with 19 now let me just do that +in + + align:start position:0% +in + + + align:start position:0% +in +letters so that's y transpose y + + align:start position:0% +letters so that's y transpose y + + + align:start position:0% +letters so that's y transpose y +Y and this is x + y transpose x + + + align:start position:0% +Y and this is x + y transpose x + + + + align:start position:0% +Y and this is x + y transpose x + +y okay so I'm looking again this isn't + + align:start position:0% +y okay so I'm looking again this isn't + + + align:start position:0% +y okay so I'm looking again this isn't +always true I repeat this is going to be + + align:start position:0% +always true I repeat this is going to be + + + align:start position:0% +always true I repeat this is going to be +true when we have a right + + align:start position:0% +true when we have a right + + + align:start position:0% +true when we have a right +angle and let's just well of course I'm + + align:start position:0% +angle and let's just well of course I'm + + + align:start position:0% +angle and let's just well of course I'm +just going to simplify this stuff here + + align:start position:0% +just going to simplify this stuff here + + + align:start position:0% +just going to simplify this stuff here +there's an X transpose X there and + + align:start position:0% +there's an X transpose X there and + + + align:start position:0% +there's an X transpose X there and +there's a y transpose y there + + align:start position:0% +there's a y transpose y there + + + align:start position:0% +there's a y transpose y there +and there's an X transpose + + align:start position:0% +and there's an X transpose + + + align:start position:0% +and there's an X transpose +Y and there's a y transpose + + align:start position:0% + + + + align:start position:0% + +X I knew I could do that simplification + + align:start position:0% +X I knew I could do that simplification + + + align:start position:0% +X I knew I could do that simplification +because I'm just doing matrix + + align:start position:0% +because I'm just doing matrix + + + align:start position:0% +because I'm just doing matrix +multiplication and I've just followed + + align:start position:0% +multiplication and I've just followed + + + align:start position:0% +multiplication and I've just followed +the rules okay so X transpose X is + + align:start position:0% +the rules okay so X transpose X is + + + align:start position:0% +the rules okay so X transpose X is +cancel y transpose y's cancel and what + + align:start position:0% +cancel y transpose y's cancel and what + + + align:start position:0% +cancel y transpose y's cancel and what +about these guys what can what can you + + align:start position:0% +about these guys what can what can you + + + align:start position:0% +about these guys what can what can you +tell me about + + align:start position:0% + + + + align:start position:0% + +the inner product of X with Y and the + + align:start position:0% +the inner product of X with Y and the + + + align:start position:0% +the inner product of X with Y and the +inner product of Y with + + align:start position:0% +inner product of Y with + + + align:start position:0% +inner product of Y with +X is there a + + align:start position:0% +X is there a + + + align:start position:0% +X is there a +difference I think if we while we're + + align:start position:0% +difference I think if we while we're + + + align:start position:0% +difference I think if we while we're +doing + + align:start position:0% + + + + align:start position:0% + +real vectors which is all we're doing + + align:start position:0% +real vectors which is all we're doing + + + align:start position:0% +real vectors which is all we're doing +now there isn't a difference there's no + + align:start position:0% +now there isn't a difference there's no + + + align:start position:0% +now there isn't a difference there's no +difference if I take X transpose y + + align:start position:0% +difference if I take X transpose y + + + align:start position:0% +difference if I take X transpose y +that'll give me zero if I took y + + align:start position:0% +that'll give me zero if I took y + + + align:start position:0% +that'll give me zero if I took y +transpose X I would have the same X1 y1 + + align:start position:0% +transpose X I would have the same X1 y1 + + + align:start position:0% +transpose X I would have the same X1 y1 +and X2 Y2 and X3 Y3 it would be the same + + align:start position:0% +and X2 Y2 and X3 Y3 it would be the same + + + align:start position:0% +and X2 Y2 and X3 Y3 it would be the same +so this is this is this is the same as + + align:start position:0% +so this is this is this is the same as + + + align:start position:0% +so this is this is this is the same as +that this is really I'll I'll knock that + + align:start position:0% +that this is really I'll I'll knock that + + + align:start position:0% +that this is really I'll I'll knock that +guy out and say two of + + align:start position:0% + + + + align:start position:0% + +these so actually that's the this this + + align:start position:0% +these so actually that's the this this + + + align:start position:0% +these so actually that's the this this +equation boiled down to this thing being + + align:start position:0% +equation boiled down to this thing being + + + align:start position:0% +equation boiled down to this thing being +zero right everything else cancelled and + + align:start position:0% +zero right everything else cancelled and + + + align:start position:0% +zero right everything else cancelled and +this equation boiled down to that one so + + align:start position:0% +this equation boiled down to that one so + + + align:start position:0% +this equation boiled down to that one so +that's really all I wanted + + align:start position:0% +that's really all I wanted + + + align:start position:0% +that's really all I wanted +I just wanted to check + + align:start position:0% +I just wanted to check + + + align:start position:0% +I just wanted to check +that + + align:start position:0% +that + + + align:start position:0% +that +Pythagoras for a right + + align:start position:0% +Pythagoras for a right + + + align:start position:0% +Pythagoras for a right +triangle led me to this of course I + + align:start position:0% +triangle led me to this of course I + + + align:start position:0% +triangle led me to this of course I +cancel the two now no problem to X + + align:start position:0% +cancel the two now no problem to X + + + align:start position:0% +cancel the two now no problem to X +transpose yal 0 as the + + align:start position:0% +transpose yal 0 as the + + + align:start position:0% +transpose yal 0 as the +test fair enough okay you knew it was + + align:start position:0% +test fair enough okay you knew it was + + + align:start position:0% +test fair enough okay you knew it was +coming the dotproduct of orthogonal + + align:start position:0% +coming the dotproduct of orthogonal + + + align:start position:0% +coming the dotproduct of orthogonal +vectors is zero it's just I just want to + + align:start position:0% +vectors is zero it's just I just want to + + + align:start position:0% +vectors is zero it's just I just want to +say that's really neat it comes that it + + align:start position:0% +say that's really neat it comes that it + + + align:start position:0% +say that's really neat it comes that it +comes out so well all + + align:start position:0% +comes out so well all + + + align:start position:0% +comes out so well all +right now what about so now I know if + + align:start position:0% +right now what about so now I know if + + + align:start position:0% +right now what about so now I know if +two vect what it means when two vectors + + align:start position:0% +two vect what it means when two vectors + + + align:start position:0% +two vect what it means when two vectors +are orthogonal by the way what about if + + align:start position:0% +are orthogonal by the way what about if + + + align:start position:0% +are orthogonal by the way what about if +one of these guys is the zero + + align:start position:0% +one of these guys is the zero + + + align:start position:0% +one of these guys is the zero +Vector suppose X is the zero vector and + + align:start position:0% +Vector suppose X is the zero vector and + + + align:start position:0% +Vector suppose X is the zero vector and +Y is + + align:start position:0% +Y is + + + align:start position:0% +Y is +whatever are they + + align:start position:0% +whatever are they + + + align:start position:0% +whatever are they +orthogonal + + align:start position:0% +orthogonal + + + align:start position:0% +orthogonal +sure in math the one thing about math is + + align:start position:0% +sure in math the one thing about math is + + + align:start position:0% +sure in math the one thing about math is +you're supposed to follow the + + align:start position:0% +you're supposed to follow the + + + align:start position:0% +you're supposed to follow the +rules so you're supposed to if if x is + + align:start position:0% +rules so you're supposed to if if x is + + + align:start position:0% +rules so you're supposed to if if x is +the zero Vector you're supposed to take + + align:start position:0% +the zero Vector you're supposed to take + + + align:start position:0% +the zero Vector you're supposed to take +the zero Vector dotted with Y and of + + align:start position:0% +the zero Vector dotted with Y and of + + + align:start position:0% +the zero Vector dotted with Y and of +course you get always get zero so just + + align:start position:0% +course you get always get zero so just + + + align:start position:0% +course you get always get zero so just +so we're all sure the zero Vector is + + align:start position:0% +so we're all sure the zero Vector is + + + align:start position:0% +so we're all sure the zero Vector is +orthogonal to + + align:start position:0% +orthogonal to + + + align:start position:0% +orthogonal to +everybody but what I want + + align:start position:0% +everybody but what I want + + + align:start position:0% +everybody but what I want +to what I now want + + align:start position:0% +to what I now want + + + align:start position:0% +to what I now want +to uh speak about about is + + align:start position:0% + + + + align:start position:0% + +subspaces what does it mean for me to + + align:start position:0% +subspaces what does it mean for me to + + + align:start position:0% +subspaces what does it mean for me to +say that some Subspace is orthogonal to + + align:start position:0% +say that some Subspace is orthogonal to + + + align:start position:0% +say that some Subspace is orthogonal to +some other + + align:start position:0% +some other + + + align:start position:0% +some other +Subspace so okay now I've got to write + + align:start position:0% +Subspace so okay now I've got to write + + + align:start position:0% +Subspace so okay now I've got to write +this down so because we're defining + + align:start position:0% +this down so because we're defining + + + align:start position:0% +this down so because we're defining +definition of + + align:start position:0% +definition of + + + align:start position:0% +definition of +Subspace + + align:start position:0% +Subspace + + + align:start position:0% +Subspace +s is orthogonal + + align:start position:0% +s is orthogonal + + + align:start position:0% +s is orthogonal +so + + align:start position:0% +so + + + align:start position:0% +so +to + + align:start position:0% +to + + + align:start position:0% +to +Subspace + + align:start position:0% +Subspace + + + align:start position:0% +Subspace +let's say + + align:start position:0% +let's say + + + align:start position:0% +let's say +t so I've got a couple of + + align:start position:0% + + + + align:start position:0% + +subspaces and what should it mean for + + align:start position:0% +subspaces and what should it mean for + + + align:start position:0% +subspaces and what should it mean for +those guys to be + + align:start position:0% +those guys to be + + + align:start position:0% +those guys to be +orthogonal it's just a n sort of what's + + align:start position:0% +orthogonal it's just a n sort of what's + + + align:start position:0% +orthogonal it's just a n sort of what's +the natural extension from orthogonal + + align:start position:0% +the natural extension from orthogonal + + + align:start position:0% +the natural extension from orthogonal +vectors to orthogonal + + align:start position:0% +vectors to orthogonal + + + align:start position:0% +vectors to orthogonal +subspaces well and in + + align:start position:0% + + + + align:start position:0% + +particular let's think of some + + align:start position:0% +particular let's think of some + + + align:start position:0% +particular let's think of some +orthogonal subspaces like like + + align:start position:0% +orthogonal subspaces like like + + + align:start position:0% +orthogonal subspaces like like +uh uh this + + align:start position:0% +uh uh this + + + align:start position:0% +uh uh this +wall let's say in three + + align:start position:0% +wall let's say in three + + + align:start position:0% +wall let's say in three +dimensions so the Blackboard extended to + + align:start position:0% +dimensions so the Blackboard extended to + + + align:start position:0% +dimensions so the Blackboard extended to +Infinity right is a is a Subspace a + + align:start position:0% +Infinity right is a is a Subspace a + + + align:start position:0% +Infinity right is a is a Subspace a +plane a two-dimensional + + align:start position:0% + + + + align:start position:0% + +Subspace it's a little bumpy but anyway + + align:start position:0% +Subspace it's a little bumpy but anyway + + + align:start position:0% +Subspace it's a little bumpy but anyway +it's a think of it as a + + align:start position:0% +it's a think of it as a + + + align:start position:0% +it's a think of it as a +Subspace um let me take the floor as + + align:start position:0% +Subspace um let me take the floor as + + + align:start position:0% +Subspace um let me take the floor as +another + + align:start position:0% +another + + + align:start position:0% +another +Subspace + + align:start position:0% + + + + align:start position:0% + +again it's not uh great Subspace MIT + + align:start position:0% +again it's not uh great Subspace MIT + + + align:start position:0% +again it's not uh great Subspace MIT +only Built it like so so but + + align:start position:0% +only Built it like so so but + + + align:start position:0% +only Built it like so so but +uh and I'll put the origin right here so + + align:start position:0% +uh and I'll put the origin right here so + + + align:start position:0% +uh and I'll put the origin right here so +the origin of the world is right + + align:start position:0% +the origin of the world is right + + + align:start position:0% +the origin of the world is right +there + + align:start position:0% + + + + align:start position:0% + +okay thereby giving linear algebra it's + + align:start position:0% +okay thereby giving linear algebra it's + + + align:start position:0% +okay thereby giving linear algebra it's +proper importance in in this okay so + + align:start position:0% +proper importance in in this okay so + + + align:start position:0% +proper importance in in this okay so +there's one Subspace there's another one + + align:start position:0% +there's one Subspace there's another one + + + align:start position:0% +there's one Subspace there's another one +the + + align:start position:0% +the + + + align:start position:0% +the +floor + + align:start position:0% +floor + + + align:start position:0% +floor +and are they + + align:start position:0% +and are they + + + align:start position:0% +and are they +orthogon what does it mean for two + + align:start position:0% +orthogon what does it mean for two + + + align:start position:0% +orthogon what does it mean for two +subspaces to be orthogonal and and in + + align:start position:0% +subspaces to be orthogonal and and in + + + align:start position:0% +subspaces to be orthogonal and and in +that special case are they orthogonal + + align:start position:0% +that special case are they orthogonal + + + align:start position:0% +that special case are they orthogonal +all right let let's finish this sentence + + align:start position:0% +all right let let's finish this sentence + + + align:start position:0% +all right let let's finish this sentence +what does it mean + + align:start position:0% + + + + align:start position:0% + +means we have to have to know what what + + align:start position:0% +means we have to have to know what what + + + align:start position:0% +means we have to have to know what what +we're talking about here so what would + + align:start position:0% +we're talking about here so what would + + + align:start position:0% +we're talking about here so what would +be a reasonable idea of + + align:start position:0% +be a reasonable idea of + + + align:start position:0% +be a reasonable idea of +orthography well let me put the right + + align:start position:0% +orthography well let me put the right + + + align:start position:0% +orthography well let me put the right +thing up it means that every Vector in + + align:start position:0% +thing up it means that every Vector in + + + align:start position:0% +thing up it means that every Vector in +s + + align:start position:0% +s + + + align:start position:0% +s +every + + align:start position:0% +every + + + align:start position:0% +every +Vector in + + align:start position:0% +Vector in + + + align:start position:0% +Vector in +S is + + align:start position:0% + + + + align:start position:0% + +orthogonal + + align:start position:0% + + + + align:start position:0% + +to to what am I going to say + + align:start position:0% +to to what am I going to say + + + align:start position:0% +to to what am I going to say +every Vector in + + align:start position:0% + + + + align:start position:0% + +P + + align:start position:0% +P + + + align:start position:0% +P +that that's a reasonable and it's a good + + align:start position:0% +that that's a reasonable and it's a good + + + align:start position:0% +that that's a reasonable and it's a good +and it's the right definition for two + + align:start position:0% +and it's the right definition for two + + + align:start position:0% +and it's the right definition for two +subspaces to be orthogonal but I just + + align:start position:0% +subspaces to be orthogonal but I just + + + align:start position:0% +subspaces to be orthogonal but I just +want you to see hey what does that + + align:start position:0% +want you to see hey what does that + + + align:start position:0% +want you to see hey what does that +mean so answer the question about the + + align:start position:0% +mean so answer the question about the + + + align:start position:0% +mean so answer the question about the +the Blackboard and the + + align:start position:0% +the Blackboard and the + + + align:start position:0% +the Blackboard and the +floor are those two subspaces they're + + align:start position:0% +floor are those two subspaces they're + + + align:start position:0% +floor are those two subspaces they're +they're two-dimensional right and we're + + align:start position:0% +they're two-dimensional right and we're + + + align:start position:0% +they're two-dimensional right and we're +in + + align:start position:0% +in + + + align:start position:0% +in +R3 it's like the XZ plane or something + + align:start position:0% +R3 it's like the XZ plane or something + + + align:start position:0% +R3 it's like the XZ plane or something +and the XY + + align:start position:0% + + + + align:start position:0% + +plane are they + + align:start position:0% +plane are they + + + align:start position:0% +plane are they +orthogonal is every Vector in the black + + align:start position:0% +orthogonal is every Vector in the black + + + align:start position:0% +orthogonal is every Vector in the black +board orthogonal to every Vector in the + + align:start position:0% +board orthogonal to every Vector in the + + + align:start position:0% +board orthogonal to every Vector in the +floor starting from the origin right + + align:start position:0% + + + + align:start position:0% + +there yes or no I could take a + + align:start position:0% +there yes or no I could take a + + + align:start position:0% +there yes or no I could take a +vote probably get some yeses and some + + align:start position:0% +vote probably get some yeses and some + + + align:start position:0% +vote probably get some yeses and some +NOS no is the answer they're not you can + + align:start position:0% +NOS no is the answer they're not you can + + + align:start position:0% +NOS no is the answer they're not you can +tell me a vector in the Blackboard and a + + align:start position:0% +tell me a vector in the Blackboard and a + + + align:start position:0% +tell me a vector in the Blackboard and a +vector in the floor that are not + + align:start position:0% + + + + align:start position:0% + +orthogonal uh which which well you can + + align:start position:0% +orthogonal uh which which well you can + + + align:start position:0% +orthogonal uh which which well you can +tell me quite a few I guess maybe like I + + align:start position:0% +tell me quite a few I guess maybe like I + + + align:start position:0% +tell me quite a few I guess maybe like I +could take some 45° guy in the + + align:start position:0% +could take some 45° guy in the + + + align:start position:0% +could take some 45° guy in the +Blackboard and some thing in the + + align:start position:0% +Blackboard and some thing in the + + + align:start position:0% +Blackboard and some thing in the +floor that that aren't at 90° right in + + align:start position:0% +floor that that aren't at 90° right in + + + align:start position:0% +floor that that aren't at 90° right in +fact even more you could tell me a + + align:start position:0% +fact even more you could tell me a + + + align:start position:0% +fact even more you could tell me a +vector that's in both the Blackboard + + align:start position:0% +vector that's in both the Blackboard + + + align:start position:0% +vector that's in both the Blackboard +plane and the floor plane so it's + + align:start position:0% +plane and the floor plane so it's + + + align:start position:0% +plane and the floor plane so it's +certainly not orthogonal to itself so + + align:start position:0% +certainly not orthogonal to itself so + + + align:start position:0% +certainly not orthogonal to itself so +for sure those two planes aren't + + align:start position:0% +for sure those two planes aren't + + + align:start position:0% +for sure those two planes aren't +orthog what would that be so what's a + + align:start position:0% +orthog what would that be so what's a + + + align:start position:0% +orthog what would that be so what's a +vector that's in the + + align:start position:0% +vector that's in the + + + align:start position:0% +vector that's in the +like in in both of those + + align:start position:0% +like in in both of those + + + align:start position:0% +like in in both of those +planes this this guy running along the + + align:start position:0% +planes this this guy running along the + + + align:start position:0% +planes this this guy running along the +crack there where the intersection the + + align:start position:0% +crack there where the intersection the + + + align:start position:0% +crack there where the intersection the +intersection a + + align:start position:0% +intersection a + + + align:start position:0% +intersection a +vector if two subspaces meet some Vector + + align:start position:0% +vector if two subspaces meet some Vector + + + align:start position:0% +vector if two subspaces meet some Vector +well then for sure they're not + + align:start position:0% +well then for sure they're not + + + align:start position:0% +well then for sure they're not +orthogonal + + align:start position:0% +orthogonal + + + align:start position:0% +orthogonal +because that Vector is in one and it's + + align:start position:0% +because that Vector is in one and it's + + + align:start position:0% +because that Vector is in one and it's +in the other and it's not orthogonal to + + align:start position:0% +in the other and it's not orthogonal to + + + align:start position:0% +in the other and it's not orthogonal to +itself unless it's zero so the only I + + align:start position:0% +itself unless it's zero so the only I + + + align:start position:0% +itself unless it's zero so the only I +mean so or + + align:start position:0% +mean so or + + + align:start position:0% +mean so or +oral if for me to say these two + + align:start position:0% +oral if for me to say these two + + + align:start position:0% +oral if for me to say these two +subspaces are orthogonal first of all + + align:start position:0% +subspaces are orthogonal first of all + + + align:start position:0% +subspaces are orthogonal first of all +I'm certainly saying that they don't + + align:start position:0% +I'm certainly saying that they don't + + + align:start position:0% +I'm certainly saying that they don't +intersect in + + align:start position:0% + + + + align:start position:0% + +any uh nonzero B but also I mean more + + align:start position:0% +any uh nonzero B but also I mean more + + + align:start position:0% +any uh nonzero B but also I mean more +than that just not intersecting isn't + + align:start position:0% +than that just not intersecting isn't + + + align:start position:0% +than that just not intersecting isn't +good enough so give me an + + align:start position:0% +good enough so give me an + + + align:start position:0% +good enough so give me an +example oh that's say in the + + align:start position:0% +example oh that's say in the + + + align:start position:0% +example oh that's say in the +plane oh what when do we have orthog + + align:start position:0% +plane oh what when do we have orthog + + + align:start position:0% +plane oh what when do we have orthog +subspaces in the plane yeah tell me in + + align:start position:0% +subspaces in the plane yeah tell me in + + + align:start position:0% +subspaces in the plane yeah tell me in +the plane so we don't there aren't that + + align:start position:0% +the plane so we don't there aren't that + + + align:start position:0% +the plane so we don't there aren't that +many different subspaces in the plane + + align:start position:0% +many different subspaces in the plane + + + align:start position:0% +many different subspaces in the plane +what what have we got in the plane as + + align:start position:0% +what what have we got in the plane as + + + align:start position:0% +what what have we got in the plane as +possible sub + + align:start position:0% +possible sub + + + align:start position:0% +possible sub +spaces the zero Vector real + + align:start position:0% +spaces the zero Vector real + + + align:start position:0% +spaces the zero Vector real +small uh aign through the + + align:start position:0% +small uh aign through the + + + align:start position:0% +small uh aign through the +origin or the whole + + align:start position:0% +origin or the whole + + + align:start position:0% +origin or the whole +plane okay now so when is a line through + + align:start position:0% +plane okay now so when is a line through + + + align:start position:0% +plane okay now so when is a line through +the origin orthogonal to the whole + + align:start position:0% +the origin orthogonal to the whole + + + align:start position:0% +the origin orthogonal to the whole +plane + + align:start position:0% +plane + + + align:start position:0% +plane +never right never when is a line through + + align:start position:0% +never right never when is a line through + + + align:start position:0% +never right never when is a line through +the origin orthogonal to the zero + + align:start position:0% + + + + align:start position:0% + +Subspace always right when is a line + + align:start position:0% +Subspace always right when is a line + + + align:start position:0% +Subspace always right when is a line +through the origin orthogonal to a a + + align:start position:0% +through the origin orthogonal to a a + + + align:start position:0% +through the origin orthogonal to a a +different line through the origin well + + align:start position:0% +different line through the origin well + + + align:start position:0% +different line through the origin well +that's the case that we all have a clear + + align:start position:0% +that's the case that we all have a clear + + + align:start position:0% +that's the case that we all have a clear +picture of they the two lines have to + + align:start position:0% +picture of they the two lines have to + + + align:start position:0% +picture of they the two lines have to +meet at 90° they have only the so that + + align:start position:0% +meet at 90° they have only the so that + + + align:start position:0% +meet at 90° they have only the so that +so that's like this simple case I'm + + align:start position:0% +so that's like this simple case I'm + + + align:start position:0% +so that's like this simple case I'm +talking about there's one Subspace + + align:start position:0% +talking about there's one Subspace + + + align:start position:0% +talking about there's one Subspace +there's the other Subspace they only + + align:start position:0% +there's the other Subspace they only + + + align:start position:0% +there's the other Subspace they only +meet at zero and they're orthog okay + + align:start position:0% +meet at zero and they're orthog okay + + + align:start position:0% +meet at zero and they're orthog okay +now so we now know what it means for two + + align:start position:0% +now so we now know what it means for two + + + align:start position:0% +now so we now know what it means for two +subspaces to be orthogonal and now I + + align:start position:0% +subspaces to be orthogonal and now I + + + align:start position:0% +subspaces to be orthogonal and now I +want to say that this is true for the + + align:start position:0% +want to say that this is true for the + + + align:start position:0% +want to say that this is true for the +row space and the null space okay so + + align:start position:0% +row space and the null space okay so + + + align:start position:0% +row space and the null space okay so +that's the that's the neat fact so row + + align:start position:0% + + + + align:start position:0% + +space is + + align:start position:0% + + + + align:start position:0% + +orthogonal to the null space now how did + + align:start position:0% +orthogonal to the null space now how did + + + align:start position:0% +orthogonal to the null space now how did +I come up with + + align:start position:0% + + + + align:start position:0% + +that but you see the like it's great + + align:start position:0% +that but you see the like it's great + + + align:start position:0% +that but you see the like it's great +that means that these that these + + align:start position:0% +that means that these that these + + + align:start position:0% +that means that these that these +subspaces are just the right things + + align:start position:0% +subspaces are just the right things + + + align:start position:0% +subspaces are just the right things +they're just cutting the cutting the + + align:start position:0% +they're just cutting the cutting the + + + align:start position:0% +they're just cutting the cutting the +whole Space up into two perpendicular + + align:start position:0% +whole Space up into two perpendicular + + + align:start position:0% +whole Space up into two perpendicular +subspaces Okay so + + align:start position:0% + + + + align:start position:0% + +why well what have I + + align:start position:0% +why well what have I + + + align:start position:0% +why well what have I +got to work with all I know is the null + + align:start position:0% +got to work with all I know is the null + + + align:start position:0% +got to work with all I know is the null +space the null space has vectors that + + align:start position:0% +space the null space has vectors that + + + align:start position:0% +space the null space has vectors that +solve a x = z so this is a this is a guy + + align:start position:0% +solve a x = z so this is a this is a guy + + + align:start position:0% +solve a x = z so this is a this is a guy +x x is in the null + + align:start position:0% +x x is in the null + + + align:start position:0% +x x is in the null +space then ax is + + align:start position:0% +space then ax is + + + align:start position:0% +space then ax is +zero so why + + align:start position:0% +zero so why + + + align:start position:0% +zero so why +is an orthogonal to the rows of + + align:start position:0% +is an orthogonal to the rows of + + + align:start position:0% +is an orthogonal to the rows of +a if I write down axal Z which is all I + + align:start position:0% +a if I write down axal Z which is all I + + + align:start position:0% +a if I write down axal Z which is all I +know about the null + + align:start position:0% +know about the null + + + align:start position:0% +know about the null +space + + align:start position:0% +space + + + align:start position:0% +space +then I guess I want you to see that + + align:start position:0% +then I guess I want you to see that + + + align:start position:0% +then I guess I want you to see that +that's telling me just that equation + + align:start position:0% +that's telling me just that equation + + + align:start position:0% +that's telling me just that equation +right there is telling + + align:start position:0% +right there is telling + + + align:start position:0% +right there is telling +me that the rows of a let me write it + + align:start position:0% +me that the rows of a let me write it + + + align:start position:0% +me that the rows of a let me write it +out there's Row one of + + align:start position:0% +out there's Row one of + + + align:start position:0% +out there's Row one of +a row + + align:start position:0% +a row + + + align:start position:0% +a row +two row M + + align:start position:0% +two row M + + + align:start position:0% +two row M +of a that that's a and it's multiplying + + align:start position:0% +of a that that's a and it's multiplying + + + align:start position:0% +of a that that's a and it's multiplying +X and it's + + align:start position:0% +X and it's + + + align:start position:0% +X and it's +producing + + align:start position:0% + + + + align:start position:0% + +zero okay written out that way you'll + + align:start position:0% +zero okay written out that way you'll + + + align:start position:0% +zero okay written out that way you'll +see + + align:start position:0% + + + + align:start position:0% + +it so I'm saying that a vector in the + + align:start position:0% +it so I'm saying that a vector in the + + + align:start position:0% +it so I'm saying that a vector in the +row space is perpendicular to this guy X + + align:start position:0% +row space is perpendicular to this guy X + + + align:start position:0% +row space is perpendicular to this guy X +in the null space and you see + + align:start position:0% +in the null space and you see + + + align:start position:0% +in the null space and you see +why because this equation equation is + + align:start position:0% +why because this equation equation is + + + align:start position:0% +why because this equation equation is +telling you that Row one of + + align:start position:0% +telling you that Row one of + + + align:start position:0% +telling you that Row one of +a multiplying that's a that's a DOT + + align:start position:0% +a multiplying that's a that's a DOT + + + align:start position:0% +a multiplying that's a that's a DOT +product right Row one away dot product + + align:start position:0% +product right Row one away dot product + + + align:start position:0% +product right Row one away dot product +with this x is producing this + + align:start position:0% +with this x is producing this + + + align:start position:0% +with this x is producing this +zero so X is orthogonal to the first + + align:start position:0% +zero so X is orthogonal to the first + + + align:start position:0% +zero so X is orthogonal to the first +row and to the second row row 2 of a x + + align:start position:0% +row and to the second row row 2 of a x + + + align:start position:0% +row and to the second row row 2 of a x +is giving that zero row M of a * X is + + align:start position:0% +is giving that zero row M of a * X is + + + align:start position:0% +is giving that zero row M of a * X is +giving that zero so X is the equation is + + align:start position:0% +giving that zero so X is the equation is + + + align:start position:0% +giving that zero so X is the equation is +telling me that X is orth to all the + + align:start position:0% +telling me that X is orth to all the + + + align:start position:0% +telling me that X is orth to all the +rows right it's just sitting there + + align:start position:0% +rows right it's just sitting there + + + align:start position:0% +rows right it's just sitting there +that's all we we it had to be sitting + + align:start position:0% +that's all we we it had to be sitting + + + align:start position:0% +that's all we we it had to be sitting +there because we didn't know anything + + align:start position:0% +there because we didn't know anything + + + align:start position:0% +there because we didn't know anything +more about the no space than this and + + align:start position:0% +more about the no space than this and + + + align:start position:0% +more about the no space than this and +now I guess to be + + align:start position:0% +now I guess to be + + + align:start position:0% +now I guess to be +totally complete here I've now checked + + align:start position:0% +totally complete here I've now checked + + + align:start position:0% +totally complete here I've now checked +that X is orthogonal to each separate + + align:start position:0% +that X is orthogonal to each separate + + + align:start position:0% +that X is orthogonal to each separate +row but what else strictly speaking do I + + align:start position:0% +row but what else strictly speaking do I + + + align:start position:0% +row but what else strictly speaking do I +have to + + align:start position:0% +have to + + + align:start position:0% +have to +do + + align:start position:0% +do + + + align:start position:0% +do +that that what to show that those + + align:start position:0% +that that what to show that those + + + align:start position:0% +that that what to show that those +subspaces are orthogonal I have to take + + align:start position:0% +subspaces are orthogonal I have to take + + + align:start position:0% +subspaces are orthogonal I have to take +this X in the null space and show that + + align:start position:0% +this X in the null space and show that + + + align:start position:0% +this X in the null space and show that +it's orthogonal to + + align:start position:0% +it's orthogonal to + + + align:start position:0% +it's orthogonal to +every Vector in the row space every + + align:start position:0% +every Vector in the row space every + + + align:start position:0% +every Vector in the row space every +Vector in the row space so what what + + align:start position:0% +Vector in the row space so what what + + + align:start position:0% +Vector in the row space so what what +else is in the row + + align:start position:0% +else is in the row + + + align:start position:0% +else is in the row +space the this row is in the row space + + align:start position:0% +space the this row is in the row space + + + align:start position:0% +space the this row is in the row space +that row is in the row space they + + align:start position:0% +that row is in the row space they + + + align:start position:0% +that row is in the row space they +they're all there but that's not the + + align:start position:0% +they're all there but that's not the + + + align:start position:0% +they're all there but that's not the +whole row space right we just have to + + align:start position:0% +whole row space right we just have to + + + align:start position:0% +whole row space right we just have to +like remember what does it mean what + + align:start position:0% +like remember what does it mean what + + + align:start position:0% +like remember what does it mean what +does that word space telling + + align:start position:0% + + + + align:start position:0% + +and what else is in the row + + align:start position:0% +and what else is in the row + + + align:start position:0% +and what else is in the row +space besides the + + align:start position:0% +space besides the + + + align:start position:0% +space besides the +rows all + + align:start position:0% +rows all + + + align:start position:0% +rows all +their + + align:start position:0% +their + + + align:start position:0% +their +combination so I really have to check + + align:start position:0% +combination so I really have to check + + + align:start position:0% +combination so I really have to check +that sure enough if x is perpendicular + + align:start position:0% +that sure enough if x is perpendicular + + + align:start position:0% +that sure enough if x is perpendicular +Row one row two all the all the + + align:start position:0% +Row one row two all the all the + + + align:start position:0% +Row one row two all the all the +different separate rows then also X is + + align:start position:0% +different separate rows then also X is + + + align:start position:0% +different separate rows then also X is +perpendicular to a combination of the + + align:start position:0% +perpendicular to a combination of the + + + align:start position:0% +perpendicular to a combination of the +rows and that's just matrix + + align:start position:0% +rows and that's just matrix + + + align:start position:0% +rows and that's just matrix +multiplication again you know I have + + align:start position:0% +multiplication again you know I have + + + align:start position:0% +multiplication again you know I have +Row + + align:start position:0% +Row + + + align:start position:0% +Row +one transpose X is + + align:start position:0% +one transpose X is + + + align:start position:0% +one transpose X is +zero so on row two transpose X is + + align:start position:0% + + + + align:start position:0% + +zero so I'm entitled to multiply that by + + align:start position:0% +zero so I'm entitled to multiply that by + + + align:start position:0% +zero so I'm entitled to multiply that by +some C1 this by some C2 I still have + + align:start position:0% +some C1 this by some C2 I still have + + + align:start position:0% +some C1 this by some C2 I still have +zeros I'm entitled to add so I have C1 + + align:start position:0% +zeros I'm entitled to add so I have C1 + + + align:start position:0% +zeros I'm entitled to add so I have C1 +Row one so so all this when I put that + + align:start position:0% +Row one so so all this when I put that + + + align:start position:0% +Row one so so all this when I put that +together + + align:start position:0% +together + + + align:start position:0% +together +that's big parentheses see C1 Row one + + align:start position:0% +that's big parentheses see C1 Row one + + + align:start position:0% +that's big parentheses see C1 Row one +plus C2 row2 and so on transpose X is + + align:start position:0% +plus C2 row2 and so on transpose X is + + + align:start position:0% +plus C2 row2 and so on transpose X is +zero right I just added the zeros and + + align:start position:0% +zero right I just added the zeros and + + + align:start position:0% +zero right I just added the zeros and +got zero and I just added these + + align:start position:0% +got zero and I just added these + + + align:start position:0% +got zero and I just added these +following the + + align:start position:0% + + + + align:start position:0% + +rules no no big deal the whole point was + + align:start position:0% +rules no no big deal the whole point was + + + align:start position:0% +rules no no big deal the whole point was +right sitting in that + + align:start position:0% +right sitting in that + + + align:start position:0% +right sitting in that +okay so if I come back to this figure + + align:start position:0% +okay so if I come back to this figure + + + align:start position:0% +okay so if I come back to this figure +now + + align:start position:0% +now + + + align:start position:0% +now +now I'm like a happier person cuz I have + + align:start position:0% +now I'm like a happier person cuz I have + + + align:start position:0% +now I'm like a happier person cuz I have +this uh the I now see how those + + align:start position:0% +this uh the I now see how those + + + align:start position:0% +this uh the I now see how those +subspaces are oriented and these + + align:start position:0% +subspaces are oriented and these + + + align:start position:0% +subspaces are oriented and these +subspaces are also oriented well + + align:start position:0% +subspaces are also oriented well + + + align:start position:0% +subspaces are also oriented well +actually why why is that + + align:start position:0% +actually why why is that + + + align:start position:0% +actually why why is that +orthogonality well it's the same + + align:start position:0% +orthogonality well it's the same + + + align:start position:0% +orthogonality well it's the same +statement for a transpose that that one + + align:start position:0% +statement for a transpose that that one + + + align:start position:0% +statement for a transpose that that one +was for a so I won't take time to prove + + align:start position:0% +was for a so I won't take time to prove + + + align:start position:0% +was for a so I won't take time to prove +it again because + + align:start position:0% +it again because + + + align:start position:0% +it again because +it's cuz we checked it for every Matrix + + align:start position:0% +it's cuz we checked it for every Matrix + + + align:start position:0% +it's cuz we checked it for every Matrix +and a transposes just as good a matrix + + align:start position:0% +and a transposes just as good a matrix + + + align:start position:0% +and a transposes just as good a matrix +as a so we're orthogonal over there so + + align:start position:0% +as a so we're orthogonal over there so + + + align:start position:0% +as a so we're orthogonal over there so +we really + + align:start position:0% +we really + + + align:start position:0% +we really +have carved up this these this this was + + align:start position:0% +have carved up this these this this was + + + align:start position:0% +have carved up this these this this was +like carving up M dimensional space into + + align:start position:0% +like carving up M dimensional space into + + + align:start position:0% +like carving up M dimensional space into +two + + align:start position:0% +two + + + align:start position:0% +two +subspaces and this one was carving Up N + + align:start position:0% +subspaces and this one was carving Up N + + + align:start position:0% +subspaces and this one was carving Up N +dimensional space + + align:start position:0% +dimensional space + + + align:start position:0% +dimensional space +into two + + align:start position:0% +into two + + + align:start position:0% +into two +subspaces + + align:start position:0% +subspaces + + + align:start position:0% +subspaces +and well one more thing here one more + + align:start position:0% +and well one more thing here one more + + + align:start position:0% +and well one more thing here one more +important + + align:start position:0% + + + + align:start position:0% + +thing let let me move into into into + + align:start position:0% +thing let let me move into into into + + + align:start position:0% +thing let let me move into into into +three + + align:start position:0% +three + + + align:start position:0% +three +dimensions tell me a couple of + + align:start position:0% +dimensions tell me a couple of + + + align:start position:0% +dimensions tell me a couple of +orthogonal + + align:start position:0% +orthogonal + + + align:start position:0% +orthogonal +subspaces in three + + align:start position:0% +subspaces in three + + + align:start position:0% +subspaces in three +dimensions that somehow don't carve up + + align:start position:0% +dimensions that somehow don't carve up + + + align:start position:0% +dimensions that somehow don't carve up +the whole Space stuff left + + align:start position:0% +the whole Space stuff left + + + align:start position:0% +the whole Space stuff left +there I'm thinking of a couple of + + align:start position:0% +there I'm thinking of a couple of + + + align:start position:0% +there I'm thinking of a couple of +orthogonal + + align:start position:0% +orthogonal + + + align:start position:0% +orthogonal +lines if I suppose I'm in three + + align:start position:0% +lines if I suppose I'm in three + + + align:start position:0% +lines if I suppose I'm in three +dimensions + + align:start position:0% +dimensions + + + align:start position:0% +dimensions +R3 and I have one line one + + align:start position:0% +R3 and I have one line one + + + align:start position:0% +R3 and I have one line one +onedimensional Subspace and a + + align:start position:0% +onedimensional Subspace and a + + + align:start position:0% +onedimensional Subspace and a +perpendicular one could those be the row + + align:start position:0% +perpendicular one could those be the row + + + align:start position:0% +perpendicular one could those be the row +space and the null + + align:start position:0% +space and the null + + + align:start position:0% +space and the null +space could those be the row space and + + align:start position:0% +space could those be the row space and + + + align:start position:0% +space could those be the row space and +the null space could I could I be in + + align:start position:0% +the null space could I could I be in + + + align:start position:0% +the null space could I could I be in +three + + align:start position:0% +three + + + align:start position:0% +three +dimensions + + align:start position:0% +dimensions + + + align:start position:0% +dimensions +and have a row space that's a line and a + + align:start position:0% +and have a row space that's a line and a + + + align:start position:0% +and have a row space that's a line and a +null space that's a + + align:start position:0% +null space that's a + + + align:start position:0% +null space that's a +line no why + + align:start position:0% +line no why + + + align:start position:0% +line no why +not because the dimensions aren't right + + align:start position:0% +not because the dimensions aren't right + + + align:start position:0% +not because the dimensions aren't right +right the dimensions are no good the the + + align:start position:0% +right the dimensions are no good the the + + + align:start position:0% +right the dimensions are no good the the +dimensions here R and N minus r they add + + align:start position:0% +dimensions here R and N minus r they add + + + align:start position:0% +dimensions here R and N minus r they add +up to three they add up to + + align:start position:0% +up to three they add up to + + + align:start position:0% +up to three they add up to +n if I take it's just if I just follow + + align:start position:0% +n if I take it's just if I just follow + + + align:start position:0% +n if I take it's just if I just follow +that + + align:start position:0% +that + + + align:start position:0% +that +example if if if + + align:start position:0% +example if if if + + + align:start position:0% +example if if if +if the row space is onedimensional + + align:start position:0% +if the row space is onedimensional + + + align:start position:0% +if the row space is onedimensional +suppose a is what's a good in I'm in R3 + + align:start position:0% +suppose a is what's a good in I'm in R3 + + + align:start position:0% +suppose a is what's a good in I'm in R3 +I want a one-dimensional row space let + + align:start position:0% +I want a one-dimensional row space let + + + align:start position:0% +I want a one-dimensional row space let +me take 1 25 2 + + align:start position:0% +me take 1 25 2 + + + align:start position:0% +me take 1 25 2 +41 what's the dimension of that row + + align:start position:0% + + + + align:start position:0% + +space + + align:start position:0% +space + + + align:start position:0% +space +one what's the dimension of the null + + align:start position:0% + + + + align:start position:0% + +space tell what's the null space look + + align:start position:0% +space tell what's the null space look + + + align:start position:0% +space tell what's the null space look +look like in that case the row space is + + align:start position:0% +look like in that case the row space is + + + align:start position:0% +look like in that case the row space is +a line right onedimensional it's just a + + align:start position:0% +a line right onedimensional it's just a + + + align:start position:0% +a line right onedimensional it's just a +line through + + align:start position:0% + + + + align:start position:0% + +125 geometrically what's the row space + + align:start position:0% +125 geometrically what's the row space + + + align:start position:0% +125 geometrically what's the row space +look + + align:start position:0% +look + + + align:start position:0% +look +like it's + + align:start position:0% +like it's + + + align:start position:0% +like it's +a what's its Dimension so so here our + + align:start position:0% +a what's its Dimension so so here our + + + align:start position:0% +a what's its Dimension so so here our +here n is + + align:start position:0% +here n is + + + align:start position:0% +here n is +three the rank is + + align:start position:0% +three the rank is + + + align:start position:0% +three the rank is +one so the dimension of the null space + + align:start position:0% +one so the dimension of the null space + + + align:start position:0% +one so the dimension of the null space +so I'm looking + + align:start position:0% +so I'm looking + + + align:start position:0% +so I'm looking +at this x X1 X2 X3 to give + + align:start position:0% + + + + align:start position:0% + +zero so the dimension of the null space + + align:start position:0% +zero so the dimension of the null space + + + align:start position:0% +zero so the dimension of the null space +is we all know is two right it's a plane + + align:start position:0% +is we all know is two right it's a plane + + + align:start position:0% +is we all know is two right it's a plane +and now actually we know we see better + + align:start position:0% +and now actually we know we see better + + + align:start position:0% +and now actually we know we see better +what plane is it what plane is + + align:start position:0% +what plane is it what plane is + + + align:start position:0% +what plane is it what plane is +it it's the plane that's perpendicular + + align:start position:0% +it it's the plane that's perpendicular + + + align:start position:0% +it it's the plane that's perpendicular +to when + + align:start position:0% +to when + + + align:start position:0% +to when +25 right we now see in fact the 2410 + + align:start position:0% +25 right we now see in fact the 2410 + + + align:start position:0% +25 right we now see in fact the 2410 +didn't actually have any effect at all I + + align:start position:0% +didn't actually have any effect at all I + + + align:start position:0% +didn't actually have any effect at all I +could have just ignored that that didn't + + align:start position:0% +could have just ignored that that didn't + + + align:start position:0% +could have just ignored that that didn't +change the row space or the null + + align:start position:0% +change the row space or the null + + + align:start position:0% +change the row space or the null +space I'll just make that one + + align:start position:0% +space I'll just make that one + + + align:start position:0% +space I'll just make that one +equation yeah okay sure that's that's + + align:start position:0% +equation yeah okay sure that's that's + + + align:start position:0% +equation yeah okay sure that's that's +the easiest to deal with one + + align:start position:0% +the easiest to deal with one + + + align:start position:0% +the easiest to deal with one +equation three + + align:start position:0% +equation three + + + align:start position:0% +equation three +unknowns and + + align:start position:0% +unknowns and + + + align:start position:0% +unknowns and +um + + align:start position:0% +um + + + align:start position:0% +um +I want to ask + + align:start position:0% +I want to ask + + + align:start position:0% +I want to ask +uh what's what does the equation give me + + align:start position:0% +uh what's what does the equation give me + + + align:start position:0% +uh what's what does the equation give me +it gives me the null + + align:start position:0% +it gives me the null + + + align:start position:0% +it gives me the null +space and you would have + + align:start position:0% +space and you would have + + + align:start position:0% +space and you would have +said back in September you would have + + align:start position:0% +said back in September you would have + + + align:start position:0% +said back in September you would have +said it gives you a plane and we're + + align:start position:0% +said it gives you a plane and we're + + + align:start position:0% +said it gives you a plane and we're +we're completely right and the plane it + + align:start position:0% +we're completely right and the plane it + + + align:start position:0% +we're completely right and the plane it +gives you the normal Vector you remember + + align:start position:0% +gives you the normal Vector you remember + + + align:start position:0% +gives you the normal Vector you remember +in calculus there was this D normal + + align:start position:0% +in calculus there was this D normal + + + align:start position:0% +in calculus there was this D normal +Vector called n well there it is + + align:start position:0% +Vector called n well there it is + + + align:start position:0% +Vector called n well there it is + + align:start position:0% + + + align:start position:0% +okay so + + align:start position:0% +okay so + + + align:start position:0% +okay so +uh that what what is the what's the + + align:start position:0% +uh that what what is the what's the + + + align:start position:0% +uh that what what is the what's the +point I want to make here I want to make + + align:start position:0% +point I want to make here I want to make + + + align:start position:0% +point I want to make here I want to make +I want to emphasize that not only are + + align:start position:0% +I want to emphasize that not only are + + + align:start position:0% +I want to emphasize that not only are +the let me write it in + + align:start position:0% + + + + align:start position:0% + +words so I want to write the null + + align:start position:0% + + + + align:start position:0% + +space and the row space + + align:start position:0% + + + + align:start position:0% + +are + + align:start position:0% + + + + align:start position:0% + +orthogonal that's that's this neat fact + + align:start position:0% +orthogonal that's that's this neat fact + + + align:start position:0% +orthogonal that's that's this neat fact +which we we've just checked from axal Z + + align:start position:0% +which we we've just checked from axal Z + + + align:start position:0% +which we we've just checked from axal Z +but now I want to say I want to say more + + align:start position:0% +but now I want to say I want to say more + + + align:start position:0% +but now I want to say I want to say more +because there's a little more that's + + align:start position:0% +because there's a little more that's + + + align:start position:0% +because there's a little more that's +true their Dimensions add to the whole + + align:start position:0% +true their Dimensions add to the whole + + + align:start position:0% +true their Dimensions add to the whole +Space so that's like a little extra + + align:start position:0% +Space so that's like a little extra + + + align:start position:0% +Space so that's like a little extra +information + + align:start position:0% +information + + + align:start position:0% +information +that it's not like I could I couldn't + + align:start position:0% +that it's not like I could I couldn't + + + align:start position:0% +that it's not like I could I couldn't +have a line and a line in three + + align:start position:0% +have a line and a line in three + + + align:start position:0% +have a line and a line in three +dimensions those those don't add up one + + align:start position:0% +dimensions those those don't add up one + + + align:start position:0% +dimensions those those don't add up one +and one don't add to three so I use the + + align:start position:0% +and one don't add to three so I use the + + + align:start position:0% +and one don't add to three so I use the +word orthogonal + + align:start position:0% + + + + align:start position:0% + +complement + + align:start position:0% +complement + + + align:start position:0% +complement +in RN and the idea of this word + + align:start position:0% +in RN and the idea of this word + + + align:start position:0% +in RN and the idea of this word +compliment is + + align:start position:0% +compliment is + + + align:start position:0% +compliment is +that the orthogonal complement of a row + + align:start position:0% +that the orthogonal complement of a row + + + align:start position:0% +that the orthogonal complement of a row +space contains not just some vectors + + align:start position:0% +space contains not just some vectors + + + align:start position:0% +space contains not just some vectors +that are orthogonal to it but all so so + + align:start position:0% +that are orthogonal to it but all so so + + + align:start position:0% +that are orthogonal to it but all so so +what does that mean that means that the + + align:start position:0% +what does that mean that means that the + + + align:start position:0% +what does that mean that means that the +null + + align:start position:0% +null + + + align:start position:0% +null +space contains + + align:start position:0% +space contains + + + align:start position:0% +space contains +all not just some but all + + align:start position:0% +all not just some but all + + + align:start position:0% +all not just some but all +vectors that are perpendicular to the + + align:start position:0% +vectors that are perpendicular to the + + + align:start position:0% +vectors that are perpendicular to the +row + + align:start position:0% +row + + + align:start position:0% +row +space + + align:start position:0% +space + + + align:start position:0% +space +okay + + align:start position:0% +okay + + + align:start position:0% +okay +really what I've done in this half of + + align:start position:0% +really what I've done in this half of + + + align:start position:0% +really what I've done in this half of +the + + align:start position:0% +the + + + align:start position:0% +the +lecture is + + align:start position:0% +lecture is + + + align:start position:0% +lecture is +just + + align:start position:0% +just + + + align:start position:0% +just +notice some of the nice geometry that + + align:start position:0% +notice some of the nice geometry that + + + align:start position:0% +notice some of the nice geometry that +that we didn't pick up before because we + + align:start position:0% +that we didn't pick up before because we + + + align:start position:0% +that we didn't pick up before because we +didn't discuss perpendicular vectors + + align:start position:0% +didn't discuss perpendicular vectors + + + align:start position:0% +didn't discuss perpendicular vectors +before but it was all sitting there and + + align:start position:0% +before but it was all sitting there and + + + align:start position:0% +before but it was all sitting there and +now we picked it up that these vectors + + align:start position:0% +now we picked it up that these vectors + + + align:start position:0% +now we picked it up that these vectors +are orthogonal complements and I guess I + + align:start position:0% +are orthogonal complements and I guess I + + + align:start position:0% +are orthogonal complements and I guess I +even call + + align:start position:0% +even call + + + align:start position:0% +even call +this part one of the fun FAL theorem of + + align:start position:0% +this part one of the fun FAL theorem of + + + align:start position:0% +this part one of the fun FAL theorem of +linear algebra the fundamental theorem + + align:start position:0% +linear algebra the fundamental theorem + + + align:start position:0% +linear algebra the fundamental theorem +of linear algebra is about these four + + align:start position:0% +of linear algebra is about these four + + + align:start position:0% +of linear algebra is about these four +subspaces so part one is about their + + align:start position:0% +subspaces so part one is about their + + + align:start position:0% +subspaces so part one is about their +Dimension maybe I should call it part + + align:start position:0% +Dimension maybe I should call it part + + + align:start position:0% +Dimension maybe I should call it part +two + + align:start position:0% +two + + + align:start position:0% +two +now their Dimensions we + + align:start position:0% +now their Dimensions we + + + align:start position:0% +now their Dimensions we +got now we're getting their + + align:start position:0% +got now we're getting their + + + align:start position:0% +got now we're getting their +orthogonality that's part + + align:start position:0% +orthogonality that's part + + + align:start position:0% +orthogonality that's part +two and part + + align:start position:0% +two and part + + + align:start position:0% +two and part +three will be about bases for orthogonal + + align:start position:0% +three will be about bases for orthogonal + + + align:start position:0% +three will be about bases for orthogonal +bases so that's uh coming up okay so I'm + + align:start position:0% +bases so that's uh coming up okay so I'm + + + align:start position:0% +bases so that's uh coming up okay so I'm +I'm + + align:start position:0% +I'm + + + align:start position:0% +I'm +uh I'm happy with that uh geometry right + + align:start position:0% +uh I'm happy with that uh geometry right + + + align:start position:0% +uh I'm happy with that uh geometry right +now + + align:start position:0% +now + + + align:start position:0% +now +okay okay now what's my next goal in + + align:start position:0% +okay okay now what's my next goal in + + + align:start position:0% +okay okay now what's my next goal in +this chapter here's the it's the main + + align:start position:0% +this chapter here's the it's the main + + + align:start position:0% +this chapter here's the it's the main +problem of the + + align:start position:0% +problem of the + + + align:start position:0% +problem of the +chapter the main problem of the chapter + + align:start position:0% +chapter the main problem of the chapter + + + align:start position:0% +chapter the main problem of the chapter +is so this is + + align:start position:0% +is so this is + + + align:start position:0% +is so this is +coming coming + + align:start position:0% + + + + align:start position:0% + +attraction this is this is the very last + + align:start position:0% +attraction this is this is the very last + + + align:start position:0% +attraction this is this is the very last +chapter that's about axal + + align:start position:0% + + + + align:start position:0% + +B I would like to solve that system of + + align:start position:0% +B I would like to solve that system of + + + align:start position:0% +B I would like to solve that system of +equations when there is no + + align:start position:0% + + + + align:start position:0% + +solution you may say what a ridiculous + + align:start position:0% +solution you may say what a ridiculous + + + align:start position:0% +solution you may say what a ridiculous +thing to do but but I have to say I it's + + align:start position:0% +thing to do but but I have to say I it's + + + align:start position:0% +thing to do but but I have to say I it's +done all the time in fact it has to be + + align:start position:0% +done all the time in fact it has to be + + + align:start position:0% +done all the time in fact it has to be +done you get so so the problem is + + align:start position:0% +done you get so so the problem is + + + align:start position:0% +done you get so so the problem is +solve as the best possible solve I'll + + align:start position:0% +solve as the best possible solve I'll + + + align:start position:0% +solve as the best possible solve I'll +put + + align:start position:0% + + + + align:start position:0% + +quote ax B + + align:start position:0% +quote ax B + + + align:start position:0% +quote ax B +when there + + align:start position:0% +when there + + + align:start position:0% +when there +is no + + align:start position:0% + + + + align:start position:0% + +solution and of course what does that + + align:start position:0% +solution and of course what does that + + + align:start position:0% +solution and of course what does that +mean b isn't in the in the column + + align:start position:0% +mean b isn't in the in the column + + + align:start position:0% +mean b isn't in the in the column +space and it's quite typical if this + + align:start position:0% +space and it's quite typical if this + + + align:start position:0% +space and it's quite typical if this +Matrix a is rectangular if I maybe I + + align:start position:0% +Matrix a is rectangular if I maybe I + + + align:start position:0% +Matrix a is rectangular if I maybe I +have M equations and that's bigger than + + align:start position:0% +have M equations and that's bigger than + + + align:start position:0% +have M equations and that's bigger than +the number of + + align:start position:0% +the number of + + + align:start position:0% +the number of +unknowns then for sure the + + align:start position:0% +unknowns then for sure the + + + align:start position:0% +unknowns then for sure the +rank is not M the rank couldn't be M now + + align:start position:0% +rank is not M the rank couldn't be M now + + + align:start position:0% +rank is not M the rank couldn't be M now +so there will be a lot of right hand + + align:start position:0% +so there will be a lot of right hand + + + align:start position:0% +so there will be a lot of right hand +sides with no solution + + align:start position:0% + + + + align:start position:0% + +but it here's an + + align:start position:0% +but it here's an + + + align:start position:0% +but it here's an +example some satellite is buzzing along + + align:start position:0% +example some satellite is buzzing along + + + align:start position:0% +example some satellite is buzzing along +you measure its + + align:start position:0% +you measure its + + + align:start position:0% +you measure its +position you make a th + + align:start position:0% +position you make a th + + + align:start position:0% +position you make a th +measurements so that gives you a th + + align:start position:0% +measurements so that gives you a th + + + align:start position:0% +measurements so that gives you a th +equations for the for the parameters + + align:start position:0% +equations for the for the parameters + + + align:start position:0% +equations for the for the parameters +that that that give the position but + + align:start position:0% +that that that give the position but + + + align:start position:0% +that that that give the position but +there aren't a thousand parameters it's + + align:start position:0% +there aren't a thousand parameters it's + + + align:start position:0% +there aren't a thousand parameters it's +just maybe + + align:start position:0% +just maybe + + + align:start position:0% +just maybe +six or you're measuring the you're doing + + align:start position:0% +six or you're measuring the you're doing + + + align:start position:0% +six or you're measuring the you're doing +question + + align:start position:0% +question + + + align:start position:0% +question +eres you're you're measuring uh uh + + align:start position:0% +eres you're you're measuring uh uh + + + align:start position:0% +eres you're you're measuring uh uh +resistances you're taking pulses you + + align:start position:0% +resistances you're taking pulses you + + + align:start position:0% +resistances you're taking pulses you +you're measuring somebody's pulse rate + + align:start position:0% +you're measuring somebody's pulse rate + + + align:start position:0% +you're measuring somebody's pulse rate +okay there's just one unknown the pulse + + align:start position:0% +okay there's just one unknown the pulse + + + align:start position:0% +okay there's just one unknown the pulse +rate so you measure it once okay fine + + align:start position:0% +rate so you measure it once okay fine + + + align:start position:0% +rate so you measure it once okay fine +but if you really want to know it you + + align:start position:0% +but if you really want to know it you + + + align:start position:0% +but if you really want to know it you +measure it multiple + + align:start position:0% +measure it multiple + + + align:start position:0% +measure it multiple +times but then the measurements have + + align:start position:0% +times but then the measurements have + + + align:start position:0% +times but then the measurements have +noise in them so there's the problem is + + align:start position:0% +noise in them so there's the problem is + + + align:start position:0% +noise in them so there's the problem is +that in many many problems we got too + + align:start position:0% +that in many many problems we got too + + + align:start position:0% +that in many many problems we got too +many equations and they've got noise in + + align:start position:0% +many equations and they've got noise in + + + align:start position:0% +many equations and they've got noise in +the right hand side so axal + + align:start position:0% +the right hand side so axal + + + align:start position:0% +the right hand side so axal +B I can't expect to solve it exactly + + align:start position:0% +B I can't expect to solve it exactly + + + align:start position:0% +B I can't expect to solve it exactly +right because I don't even know what the + + align:start position:0% +right because I don't even know what the + + + align:start position:0% +right because I don't even know what the +ER there's error there's there's a + + align:start position:0% +ER there's error there's there's a + + + align:start position:0% +ER there's error there's there's a +measurement mistake in B but there's + + align:start position:0% +measurement mistake in B but there's + + + align:start position:0% +measurement mistake in B but there's +information + + align:start position:0% +information + + + align:start position:0% +information +too there's a lot of information about X + + align:start position:0% +too there's a lot of information about X + + + align:start position:0% +too there's a lot of information about X +in there and what I want to do is like + + align:start position:0% +in there and what I want to do is like + + + align:start position:0% +in there and what I want to do is like +separate the noise the + + align:start position:0% +separate the noise the + + + align:start position:0% +separate the noise the +junk from the + + align:start position:0% +junk from the + + + align:start position:0% +junk from the +information and so this is a + + align:start position:0% +information and so this is a + + + align:start position:0% +information and so this is a +straightforward linear algebra problem + + align:start position:0% +straightforward linear algebra problem + + + align:start position:0% +straightforward linear algebra problem +how do I solve what's the best + + align:start position:0% +how do I solve what's the best + + + align:start position:0% +how do I solve what's the best +solution + + align:start position:0% +solution + + + align:start position:0% +solution +okay now let + + align:start position:0% +okay now let + + + align:start position:0% +okay now let +me um I I want to say so that's like + + align:start position:0% +me um I I want to say so that's like + + + align:start position:0% +me um I I want to say so that's like +describes the problem in a algebraic way + + align:start position:0% +describes the problem in a algebraic way + + + align:start position:0% +describes the problem in a algebraic way +I've got some equations + + align:start position:0% +I've got some equations + + + align:start position:0% +I've got some equations +I'm looking for the best solution well + + align:start position:0% +I'm looking for the best solution well + + + align:start position:0% +I'm looking for the best solution well +one way to find it is one one way sorry + + align:start position:0% +one way to find it is one one way sorry + + + align:start position:0% +one way to find it is one one way sorry +one way to find a solution is throw + + align:start position:0% + + + + align:start position:0% + +away equations until you've got a nice + + align:start position:0% +away equations until you've got a nice + + + align:start position:0% +away equations until you've got a nice +Square invertible system and solve + + align:start position:0% +Square invertible system and solve + + + align:start position:0% +Square invertible system and solve +that that's not + + align:start position:0% +that that's not + + + align:start position:0% +that that's not +satisfactory there's no reason in these + + align:start position:0% +satisfactory there's no reason in these + + + align:start position:0% +satisfactory there's no reason in these +measurements to say these measurements + + align:start position:0% +measurements to say these measurements + + + align:start position:0% +measurements to say these measurements +are perfect and these measurements are + + align:start position:0% +are perfect and these measurements are + + + align:start position:0% +are perfect and these measurements are +useless we want to use use all the + + align:start position:0% +useless we want to use use all the + + + align:start position:0% +useless we want to use use all the +measurements to get the best information + + align:start position:0% +measurements to get the best information + + + align:start position:0% +measurements to get the best information +to get the maximum information but how + + align:start position:0% +to get the maximum information but how + + + align:start position:0% +to get the maximum information but how +okay let me anticipate a matrix that's + + align:start position:0% +okay let me anticipate a matrix that's + + + align:start position:0% +okay let me anticipate a matrix that's +going to show up this a is typically + + align:start position:0% +going to show up this a is typically + + + align:start position:0% +going to show up this a is typically +rectangular but a matrix that shows up + + align:start position:0% +rectangular but a matrix that shows up + + + align:start position:0% +rectangular but a matrix that shows up +whenever you have and we've chapter 3 + + align:start position:0% +whenever you have and we've chapter 3 + + + align:start position:0% +whenever you have and we've chapter 3 +was all about rectangular + + align:start position:0% +was all about rectangular + + + align:start position:0% +was all about rectangular +maty and we know when this is solvable + + align:start position:0% +maty and we know when this is solvable + + + align:start position:0% +maty and we know when this is solvable +you could do elimination on it right but + + align:start position:0% +you could do elimination on it right but + + + align:start position:0% +you could do elimination on it right but +I'm thinking hey you do elimination and + + align:start position:0% +I'm thinking hey you do elimination and + + + align:start position:0% +I'm thinking hey you do elimination and +you get equation 0 equal other nonzeros + + align:start position:0% +you get equation 0 equal other nonzeros + + + align:start position:0% +you get equation 0 equal other nonzeros +I'm thinking we really elimination is + + align:start position:0% +I'm thinking we really elimination is + + + align:start position:0% +I'm thinking we really elimination is +going to + + align:start position:0% +going to + + + align:start position:0% +going to +fail so that's our question elimination + + align:start position:0% +fail so that's our question elimination + + + align:start position:0% +fail so that's our question elimination +will get us down to to will tell us if + + align:start position:0% +will get us down to to will tell us if + + + align:start position:0% +will get us down to to will tell us if +there is a solution or not but I'm now + + align:start position:0% +there is a solution or not but I'm now + + + align:start position:0% +there is a solution or not but I'm now +thinking + + align:start position:0% +thinking + + + align:start position:0% +thinking +not okay so what are we going to do all + + align:start position:0% +not okay so what are we going to do all + + + align:start position:0% +not okay so what are we going to do all +right I want to I want to tell you + + align:start position:0% +right I want to I want to tell you + + + align:start position:0% +right I want to I want to tell you +to jump ahead to The Matrix that will + + align:start position:0% +to jump ahead to The Matrix that will + + + align:start position:0% +to jump ahead to The Matrix that will +play a key role so this is the Matrix + + align:start position:0% +play a key role so this is the Matrix + + + align:start position:0% +play a key role so this is the Matrix +that you want to understand for this + + align:start position:0% +that you want to understand for this + + + align:start position:0% +that you want to understand for this +chapter 4 and it's the Matrix a + + align:start position:0% +chapter 4 and it's the Matrix a + + + align:start position:0% +chapter 4 and it's the Matrix a +transpose + + align:start position:0% + + + + align:start position:0% + +a + + align:start position:0% +a + + + align:start position:0% +a +what's tell me some things about that + + align:start position:0% +what's tell me some things about that + + + align:start position:0% +what's tell me some things about that +Matrix so a is this m byn Matrix + + align:start position:0% +Matrix so a is this m byn Matrix + + + align:start position:0% +Matrix so a is this m byn Matrix +rectangular but now I'm saying that the + + align:start position:0% +rectangular but now I'm saying that the + + + align:start position:0% +rectangular but now I'm saying that the +good Matrix that shows up in the end is + + align:start position:0% +good Matrix that shows up in the end is + + + align:start position:0% +good Matrix that shows up in the end is +a transpose a so tell me something about + + align:start position:0% +a transpose a so tell me something about + + + align:start position:0% +a transpose a so tell me something about +that is it yeah tell me what's the first + + align:start position:0% +that is it yeah tell me what's the first + + + align:start position:0% +that is it yeah tell me what's the first +thing you know about a + + align:start position:0% +thing you know about a + + + align:start position:0% +thing you know about a +transpose it's square right Square + + align:start position:0% +transpose it's square right Square + + + align:start position:0% +transpose it's square right Square +because this is M byn and this is n by m + + align:start position:0% +because this is M byn and this is n by m + + + align:start position:0% +because this is M byn and this is n by m +so this is the result is n byn good + + align:start position:0% +so this is the result is n byn good + + + align:start position:0% +so this is the result is n byn good +Square what + + align:start position:0% +Square what + + + align:start position:0% +Square what +else it's symmetric good it's + + align:start position:0% + + + + align:start position:0% + +symmetric cuz you remember how to do + + align:start position:0% +symmetric cuz you remember how to do + + + align:start position:0% +symmetric cuz you remember how to do +that if we transpose that + + align:start position:0% +that if we transpose that + + + align:start position:0% +that if we transpose that +Matrix let's transpose it a transpose a + + align:start position:0% +Matrix let's transpose it a transpose a + + + align:start position:0% +Matrix let's transpose it a transpose a +if I transpose it then that comes first + + align:start position:0% +if I transpose it then that comes first + + + align:start position:0% +if I transpose it then that comes first +transpose this comes + + align:start position:0% +transpose this comes + + + align:start position:0% +transpose this comes +second transpose + + align:start position:0% +second transpose + + + align:start position:0% +second transpose +and then transposing twice is leaves it + + align:start position:0% +and then transposing twice is leaves it + + + align:start position:0% +and then transposing twice is leaves it +brings it back to the same so it's + + align:start position:0% +brings it back to the same so it's + + + align:start position:0% +brings it back to the same so it's +aetric good + + align:start position:0% +aetric good + + + align:start position:0% +aetric good +now we now know how to ask more about a + + align:start position:0% +now we now know how to ask more about a + + + align:start position:0% +now we now know how to ask more about a +maker I'm interested + + align:start position:0% +maker I'm interested + + + align:start position:0% +maker I'm interested +in is it + + align:start position:0% +in is it + + + align:start position:0% +in is it +invertible if not what's its null + + align:start position:0% +invertible if not what's its null + + + align:start position:0% +invertible if not what's its null +space so I want to know about cuz cuz + + align:start position:0% +space so I want to know about cuz cuz + + + align:start position:0% +space so I want to know about cuz cuz +you're to see well let me let me + + align:start position:0% +you're to see well let me let me + + + align:start position:0% +you're to see well let me let me +even well I shouldn't do this but I will + + align:start position:0% +even well I shouldn't do this but I will + + + align:start position:0% +even well I shouldn't do this but I will +let me tell you what equation to + + align:start position:0% +let me tell you what equation to + + + align:start position:0% +let me tell you what equation to +solve when you can't solve that + + align:start position:0% +solve when you can't solve that + + + align:start position:0% +solve when you can't solve that +one the good equation comes from + + align:start position:0% +one the good equation comes from + + + align:start position:0% +one the good equation comes from +multiplying both sides by a + + align:start position:0% +multiplying both sides by a + + + align:start position:0% +multiplying both sides by a +transpose so the the the good equation + + align:start position:0% +transpose so the the the good equation + + + align:start position:0% +transpose so the the the good equation +that you get to is this one a transpose + + align:start position:0% +that you get to is this one a transpose + + + align:start position:0% +that you get to is this one a transpose +a x = a transpose + + align:start position:0% + + + + align:start position:0% + +B that will be the central equation in + + align:start position:0% +B that will be the central equation in + + + align:start position:0% +B that will be the central equation in +the + + align:start position:0% +the + + + align:start position:0% +the +chapter so I think why not tell it to + + align:start position:0% +chapter so I think why not tell it to + + + align:start position:0% +chapter so I think why not tell it to +why not admit it right away okay I have + + align:start position:0% +why not admit it right away okay I have + + + align:start position:0% +why not admit it right away okay I have +to I should really give + + align:start position:0% +to I should really give + + + align:start position:0% +to I should really give +x uh I I want to sort of indicate that + + align:start position:0% +x uh I I want to sort of indicate that + + + align:start position:0% +x uh I I want to sort of indicate that +this x isn't I mean this X + + align:start position:0% +this x isn't I mean this X + + + align:start position:0% +this x isn't I mean this X +was the solution to that equation if it + + align:start position:0% +was the solution to that equation if it + + + align:start position:0% +was the solution to that equation if it +existed but probably + + align:start position:0% +existed but probably + + + align:start position:0% +existed but probably +didn't now let me give this a different + + align:start position:0% +didn't now let me give this a different + + + align:start position:0% +didn't now let me give this a different +name X + + align:start position:0% +name X + + + align:start position:0% +name X +hat because I'm + + align:start position:0% +hat because I'm + + + align:start position:0% +hat because I'm +hoping this one will have a + + align:start position:0% +hoping this one will have a + + + align:start position:0% +hoping this one will have a +solution and I'm saying that it's my + + align:start position:0% +solution and I'm saying that it's my + + + align:start position:0% +solution and I'm saying that it's my +best + + align:start position:0% +best + + + align:start position:0% +best +solution I'll have to say what does best + + align:start position:0% +solution I'll have to say what does best + + + align:start position:0% +solution I'll have to say what does best +mean but that's going to be my my my + + align:start position:0% +mean but that's going to be my my my + + + align:start position:0% +mean but that's going to be my my my +plan I'm going to say that the best + + align:start position:0% +plan I'm going to say that the best + + + align:start position:0% +plan I'm going to say that the best +solution solves this equation so you see + + align:start position:0% +solution solves this equation so you see + + + align:start position:0% +solution solves this equation so you see +right away why I'm so interested in this + + align:start position:0% +right away why I'm so interested in this + + + align:start position:0% +right away why I'm so interested in this +Matrix a transpose a and in its + + align:start position:0% +Matrix a transpose a and in its + + + align:start position:0% +Matrix a transpose a and in its +invertibility okay now when is it + + align:start position:0% +invertibility okay now when is it + + + align:start position:0% +invertibility okay now when is it +invertible okay let me take a case let + + align:start position:0% +invertible okay let me take a case let + + + align:start position:0% +invertible okay let me take a case let +let me just do an example and then uh uh + + align:start position:0% +let me just do an example and then uh uh + + + align:start position:0% +let me just do an example and then uh uh +I I'll just pick a matrix + + align:start position:0% +I I'll just pick a matrix + + + align:start position:0% +I I'll just pick a matrix +here just so we see what a transpose a + + align:start position:0% +here just so we see what a transpose a + + + align:start position:0% +here just so we see what a transpose a +looks like so let me take a matrix a 1 1 + + align:start position:0% +looks like so let me take a matrix a 1 1 + + + align:start position:0% +looks like so let me take a matrix a 1 1 +1 1 2 five just to invent a matrix so + + align:start position:0% +1 1 2 five just to invent a matrix so + + + align:start position:0% +1 1 2 five just to invent a matrix so +there's a matrix + + align:start position:0% +there's a matrix + + + align:start position:0% +there's a matrix +a notice that it has Nal 3 rows and Nal + + align:start position:0% +a notice that it has Nal 3 rows and Nal + + + align:start position:0% +a notice that it has Nal 3 rows and Nal + + align:start position:0% + + + align:start position:0% +columns its rank + + align:start position:0% +columns its rank + + + align:start position:0% +columns its rank +is the rank of that Matrix + + align:start position:0% +is the rank of that Matrix + + + align:start position:0% +is the rank of that Matrix +is two right yeah The Columns are + + align:start position:0% +is two right yeah The Columns are + + + align:start position:0% +is two right yeah The Columns are +independent does ax equal B if I look at + + align:start position:0% +independent does ax equal B if I look at + + + align:start position:0% +independent does ax equal B if I look at +ax equal B so X is just X1 + + align:start position:0% +ax equal B so X is just X1 + + + align:start position:0% +ax equal B so X is just X1 +X2 and B is B1 B2 + + align:start position:0% + + + + align:start position:0% + +B3 do I expect to solve ax equal B what + + align:start position:0% +B3 do I expect to solve ax equal B what + + + align:start position:0% +B3 do I expect to solve ax equal B what +what's no way right I mean linear + + align:start position:0% +what's no way right I mean linear + + + align:start position:0% +what's no way right I mean linear +algebra is great but solving three + + align:start position:0% +algebra is great but solving three + + + align:start position:0% +algebra is great but solving three +equations with only two unknowns usually + + align:start position:0% +equations with only two unknowns usually + + + align:start position:0% +equations with only two unknowns usually +we can't do it we can only solve it if + + align:start position:0% +we can't do it we can only solve it if + + + align:start position:0% +we can't do it we can only solve it if +this Vector B is + + align:start position:0% + + + + align:start position:0% + +what I can solve that equation if that + + align:start position:0% +what I can solve that equation if that + + + align:start position:0% +what I can solve that equation if that +Vector B1 B2 B3 is in + + align:start position:0% +Vector B1 B2 B3 is in + + + align:start position:0% +Vector B1 B2 B3 is in +the column space if if it's a + + align:start position:0% +the column space if if it's a + + + align:start position:0% +the column space if if it's a +combination of those columns then fine + + align:start position:0% +combination of those columns then fine + + + align:start position:0% +combination of those columns then fine +but usually it won't be though the + + align:start position:0% +but usually it won't be though the + + + align:start position:0% +but usually it won't be though the +combinations just fill up a plane and + + align:start position:0% +combinations just fill up a plane and + + + align:start position:0% +combinations just fill up a plane and +most vectors aren't on that plane so + + align:start position:0% +most vectors aren't on that plane so + + + align:start position:0% +most vectors aren't on that plane so +what I'm saying is that I'm going to + + align:start position:0% +what I'm saying is that I'm going to + + + align:start position:0% +what I'm saying is that I'm going to +work with the Matrix a transpose a and I + + align:start position:0% +work with the Matrix a transpose a and I + + + align:start position:0% +work with the Matrix a transpose a and I +just want to figure out in this example + + align:start position:0% +just want to figure out in this example + + + align:start position:0% +just want to figure out in this example +what a transpose a + + align:start position:0% +what a transpose a + + + align:start position:0% +what a transpose a +is so it's 2 by two the first entry is a + + align:start position:0% +is so it's 2 by two the first entry is a + + + align:start position:0% +is so it's 2 by two the first entry is a +three the next entry is an eight this + + align:start position:0% +three the next entry is an eight this + + + align:start position:0% +three the next entry is an eight this +entry is + + align:start position:0% + + + + align:start position:0% + +a what's that + + align:start position:0% +a what's that + + + align:start position:0% +a what's that +entry eight for sure we knew it had to + + align:start position:0% +entry eight for sure we knew it had to + + + align:start position:0% +entry eight for sure we knew it had to +be and this entry is + + align:start position:0% +be and this entry is + + + align:start position:0% +be and this entry is +what that now getting out my trusting + + align:start position:0% +what that now getting out my trusting + + + align:start position:0% +what that now getting out my trusting +calculator 30 is that + + align:start position:0% +calculator 30 is that + + + align:start position:0% +calculator 30 is that +right 30 and is that Matrix invertible + + align:start position:0% +right 30 and is that Matrix invertible + + + align:start position:0% +right 30 and is that Matrix invertible +there's an a transpose + + align:start position:0% +there's an a transpose + + + align:start position:0% +there's an a transpose +a and it is invertible right 38 is not a + + align:start position:0% +a and it is invertible right 38 is not a + + + align:start position:0% +a and it is invertible right 38 is not a +multiple of 830 and and it's invertible + + align:start position:0% +multiple of 830 and and it's invertible + + + align:start position:0% +multiple of 830 and and it's invertible +and that's the normal that's what I + + align:start position:0% +and that's the normal that's what I + + + align:start position:0% +and that's the normal that's what I +expect so this is what I what I want to + + align:start position:0% +expect so this is what I what I want to + + + align:start position:0% +expect so this is what I what I want to +I want to show + + align:start position:0% +I want to show + + + align:start position:0% +I want to show +so here's the final here's the key point + + align:start position:0% +so here's the final here's the key point + + + align:start position:0% +so here's the final here's the key point +the null space of a transpose a it it + + align:start position:0% +the null space of a transpose a it it + + + align:start position:0% +the null space of a transpose a it it +it's not going to be always + + align:start position:0% + + + + align:start position:0% + +invertible tell me a matrix yeah now I + + align:start position:0% +invertible tell me a matrix yeah now I + + + align:start position:0% +invertible tell me a matrix yeah now I +have to I have to say that I can't say a + + align:start position:0% +have to I have to say that I can't say a + + + align:start position:0% +have to I have to say that I can't say a +transpose a is always invertible because + + align:start position:0% +transpose a is always invertible because + + + align:start position:0% +transpose a is always invertible because +that's asking too much I mean what could + + align:start position:0% +that's asking too much I mean what could + + + align:start position:0% +that's asking too much I mean what could +The Matrix a be for example so that a + + align:start position:0% +The Matrix a be for example so that a + + + align:start position:0% +The Matrix a be for example so that a +transpose a was not invertible + + align:start position:0% +transpose a was not invertible + + + align:start position:0% +transpose a was not invertible +well even could be the zero Matrix I + + align:start position:0% +well even could be the zero Matrix I + + + align:start position:0% +well even could be the zero Matrix I +mean that's like extreme case suppose I + + align:start position:0% +mean that's like extreme case suppose I + + + align:start position:0% +mean that's like extreme case suppose I +make this + + align:start position:0% +make this + + + align:start position:0% +make this +rank suppose I change to that + + align:start position:0% + + + + align:start position:0% + +a now I figure out a transpose a again + + align:start position:0% +a now I figure out a transpose a again + + + align:start position:0% +a now I figure out a transpose a again +and I get what do I + + align:start position:0% + + + + align:start position:0% + +get I Get + + align:start position:0% +get I Get + + + align:start position:0% +get I Get +Nine I get nine of course and here I + + align:start position:0% +Nine I get nine of course and here I + + + align:start position:0% +Nine I get nine of course and here I +get what's that + + align:start position:0% +get what's that + + + align:start position:0% +get what's that +entry + + align:start position:0% + + + + align:start position:0% + +27 and is that Matrix invertible + + align:start position:0% +27 and is that Matrix invertible + + + align:start position:0% +27 and is that Matrix invertible +no and why do I I I I knew it wouldn't + + align:start position:0% +no and why do I I I I knew it wouldn't + + + align:start position:0% +no and why do I I I I knew it wouldn't +be invertible anyway because this Matrix + + align:start position:0% +be invertible anyway because this Matrix + + + align:start position:0% +be invertible anyway because this Matrix +only has + + align:start position:0% +only has + + + align:start position:0% +only has +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +rank + + align:start position:0% +rank + + + align:start position:0% +rank +one and if I have a product of matrices + + align:start position:0% +one and if I have a product of matrices + + + align:start position:0% +one and if I have a product of matrices +of rank one the product is not going to + + align:start position:0% +of rank one the product is not going to + + + align:start position:0% +of rank one the product is not going to +have a rank bigger than + + align:start position:0% +have a rank bigger than + + + align:start position:0% +have a rank bigger than +one so I'm not surprised that the answer + + align:start position:0% +one so I'm not surprised that the answer + + + align:start position:0% +one so I'm not surprised that the answer +only has rank one and that's what + + align:start position:0% +only has rank one and that's what + + + align:start position:0% +only has rank one and that's what +I'm always happens that the rank of a + + align:start position:0% +I'm always happens that the rank of a + + + align:start position:0% +I'm always happens that the rank of a +transpose a comes out to equal the rank + + align:start position:0% +transpose a comes out to equal the rank + + + align:start position:0% +transpose a comes out to equal the rank +of + + align:start position:0% +of + + + align:start position:0% +of +a so uh yeah so the null space of a + + align:start position:0% +a so uh yeah so the null space of a + + + align:start position:0% +a so uh yeah so the null space of a +transpose a equals the null space of a + + align:start position:0% +transpose a equals the null space of a + + + align:start position:0% +transpose a equals the null space of a +the rank of a transpose + + align:start position:0% +the rank of a transpose + + + align:start position:0% +the rank of a transpose +a + + align:start position:0% +a + + + align:start position:0% +a +equals the rank of + + align:start position:0% + + + + align:start position:0% + +a so + + align:start position:0% +a so + + + align:start position:0% +a so +let's I I'll tell you in a as soon as I + + align:start position:0% +let's I I'll tell you in a as soon as I + + + align:start position:0% +let's I I'll tell you in a as soon as I +can why that's true but + + align:start position:0% + + + + align:start position:0% + +let's draw from that what the fact that + + align:start position:0% +let's draw from that what the fact that + + + align:start position:0% +let's draw from that what the fact that +I want this tells me that this Square + + align:start position:0% +I want this tells me that this Square + + + align:start position:0% +I want this tells me that this Square +symmetric Matrix is invertible if + + align:start position:0% +symmetric Matrix is invertible if + + + align:start position:0% +symmetric Matrix is invertible if +so here's my conclusion a transpose a is + + align:start position:0% + + + + align:start position:0% + +invertible if exactly when exactly + + align:start position:0% + + + + align:start position:0% + +if this null space is only got the zero + + align:start position:0% +if this null space is only got the zero + + + align:start position:0% +if this null space is only got the zero +back which means The Columns of a are + + align:start position:0% +back which means The Columns of a are + + + align:start position:0% +back which means The Columns of a are +independent so a transpose a is + + align:start position:0% +independent so a transpose a is + + + align:start position:0% +independent so a transpose a is +invertible exactly if a a + + align:start position:0% +invertible exactly if a a + + + align:start position:0% +invertible exactly if a a +has + + align:start position:0% +has + + + align:start position:0% +has +independent + + align:start position:0% + + + + align:start position:0% + +columns that's + + align:start position:0% +columns that's + + + align:start position:0% +columns that's +the that's the that's the the the fact + + align:start position:0% +the that's the that's the the the fact + + + align:start position:0% +the that's the that's the the the fact +that I need about a transpose a and then + + align:start position:0% +that I need about a transpose a and then + + + align:start position:0% +that I need about a transpose a and then +you'll see next + + align:start position:0% +you'll see next + + + align:start position:0% +you'll see next +time how a transpose a enters everything + + align:start position:0% +time how a transpose a enters everything + + + align:start position:0% +time how a transpose a enters everything +next next lecture is actually a crucial + + align:start position:0% +next next lecture is actually a crucial + + + align:start position:0% +next next lecture is actually a crucial +one here I'm preparing for it by getting + + align:start position:0% +one here I'm preparing for it by getting + + + align:start position:0% +one here I'm preparing for it by getting +us thinking about a transpose a and its + + align:start position:0% +us thinking about a transpose a and its + + + align:start position:0% +us thinking about a transpose a and its +rank is the same as the rank of a and we + + align:start position:0% +rank is the same as the rank of a and we + + + align:start position:0% +rank is the same as the rank of a and we +can decide when it's inverted okay so + + align:start position:0% +can decide when it's inverted okay so + + + align:start position:0% +can decide when it's inverted okay so +I'll see you + + align:start position:0% +I'll see you + + + align:start position:0% +I'll see you +Friday + + align:start position:0% + + + + align:start position:0% + +thanks \ No newline at end of file diff --git a/Zl92WCm30bU.txt b/Zl92WCm30bU.txt new file mode 100644 index 0000000000000000000000000000000000000000..015ea1d167885d53b5479657cf16c23b1bfd0688 --- /dev/null +++ b/Zl92WCm30bU.txt @@ -0,0 +1,10066 @@ +align:start position:0% + +all right uh let's continue our + + align:start position:0% +all right uh let's continue our + + + align:start position:0% +all right uh let's continue our +discussion of factor markets uh remember + + align:start position:0% +discussion of factor markets uh remember + + + align:start position:0% +discussion of factor markets uh remember +to set the stage we are now in the + + align:start position:0% +to set the stage we are now in the + + + align:start position:0% +to set the stage we are now in the +second half of the course talking about + + align:start position:0% +second half of the course talking about + + + align:start position:0% +second half of the course talking about +the various elements that underly the + + align:start position:0% +the various elements that underly the + + + align:start position:0% +the various elements that underly the +supply and demand model that we + + align:start position:0% +supply and demand model that we + + + align:start position:0% +supply and demand model that we +developed in the first half of the + + align:start position:0% +developed in the first half of the + + + align:start position:0% +developed in the first half of the +course and the first question we're + + align:start position:0% +course and the first question we're + + + align:start position:0% +course and the first question we're +tackling is where to W andr come from + + align:start position:0% +tackling is where to W andr come from + + + align:start position:0% +tackling is where to W andr come from +where do these prices that are the price + + align:start position:0% +where do these prices that are the price + + + align:start position:0% +where do these prices that are the price +of firm inputs where do they come from + + align:start position:0% +of firm inputs where do they come from + + + align:start position:0% +of firm inputs where do they come from +and they come of course from markets + + align:start position:0% +and they come of course from markets + + + align:start position:0% +and they come of course from markets +markets of demand and Supply markets + + align:start position:0% +markets of demand and Supply markets + + + align:start position:0% +markets of demand and Supply markets +four factors so let's start by doing the + + align:start position:0% +four factors so let's start by doing the + + + align:start position:0% +four factors so let's start by doing the +labor market + + align:start position:0% +labor market + + + align:start position:0% +labor market +equilibrium let's start by doing the + + align:start position:0% +equilibrium let's start by doing the + + + align:start position:0% +equilibrium let's start by doing the +labor market + + align:start position:0% +labor market + + + align:start position:0% +labor market +equilibrium and then we'll talk about + + align:start position:0% +equilibrium and then we'll talk about + + + align:start position:0% +equilibrium and then we'll talk about +what effect a minimum + + align:start position:0% +what effect a minimum + + + align:start position:0% +what effect a minimum +wage has in that + + align:start position:0% +wage has in that + + + align:start position:0% +wage has in that +equilibrium okay so let's look at figure + + align:start position:0% +equilibrium okay so let's look at figure + + + align:start position:0% +equilibrium okay so let's look at figure + + align:start position:0% + + + align:start position:0% +1 figure 161 puts together the labor + + align:start position:0% +1 figure 161 puts together the labor + + + align:start position:0% +1 figure 161 puts together the labor +market + + align:start position:0% +market + + + align:start position:0% +market +equilibrium we have a a demand + + align:start position:0% +equilibrium we have a a demand + + + align:start position:0% +equilibrium we have a a demand +curve the demand curve comes from firms + + align:start position:0% +curve the demand curve comes from firms + + + align:start position:0% +curve the demand curve comes from firms +because in Factor markets firms are now + + align:start position:0% +because in Factor markets firms are now + + + align:start position:0% +because in Factor markets firms are now +the demanders and people are the + + align:start position:0% +the demanders and people are the + + + align:start position:0% +the demanders and people are the +suppliers so we flipped the tables from + + align:start position:0% +suppliers so we flipped the tables from + + + align:start position:0% +suppliers so we flipped the tables from +a typical Market in a typical Market + + align:start position:0% +a typical Market in a typical Market + + + align:start position:0% +a typical Market in a typical Market +cons in a consumer goods Market I'm + + align:start position:0% +cons in a consumer goods Market I'm + + + align:start position:0% +cons in a consumer goods Market I'm +consumer goods Market firms Drive the + + align:start position:0% +consumer goods Market firms Drive the + + + align:start position:0% +consumer goods Market firms Drive the +supply curve and consumers Drive the + + align:start position:0% +supply curve and consumers Drive the + + + align:start position:0% +supply curve and consumers Drive the +demand curve that's no longer true true + + align:start position:0% +demand curve that's no longer true true + + + align:start position:0% +demand curve that's no longer true true +now firms Drive the domain curve and + + align:start position:0% +now firms Drive the domain curve and + + + align:start position:0% +now firms Drive the domain curve and +consumers Drive the supply curve so the + + align:start position:0% +consumers Drive the supply curve so the + + + align:start position:0% +consumers Drive the supply curve so the +domain curve comes from the marginal + + align:start position:0% +domain curve comes from the marginal + + + align:start position:0% +domain curve comes from the marginal +product of labor okay so we have uh a + + align:start position:0% +product of labor okay so we have uh a + + + align:start position:0% +product of labor okay so we have uh a +demand curve in labor market equilibrium + + align:start position:0% +demand curve in labor market equilibrium + + + align:start position:0% +demand curve in labor market equilibrium +here we're saying the demand curve is 70 + + align:start position:0% +here we're saying the demand curve is 70 + + + align:start position:0% +here we're saying the demand curve is 70 +minus + + align:start position:0% +minus + + + align:start position:0% +minus +W we're saying that as the wage goes up + + align:start position:0% +W we're saying that as the wage goes up + + + align:start position:0% +W we're saying that as the wage goes up +firms want fewer workers and we could + + align:start position:0% +firms want fewer workers and we could + + + align:start position:0% +firms want fewer workers and we could +see that from our earlier firm + + align:start position:0% +see that from our earlier firm + + + align:start position:0% +see that from our earlier firm +optimization okay but there's also + + align:start position:0% +optimization okay but there's also + + + align:start position:0% +optimization okay but there's also +supply curve now we talked about last + + align:start position:0% +supply curve now we talked about last + + + align:start position:0% +supply curve now we talked about last +time is the shape of the supply curve + + align:start position:0% +time is the shape of the supply curve + + + align:start position:0% +time is the shape of the supply curve +here is indeterminant and that's because + + align:start position:0% +here is indeterminant and that's because + + + align:start position:0% +here is indeterminant and that's because +income effects offset substitution + + align:start position:0% +income effects offset substitution + + + align:start position:0% +income effects offset substitution +effects when Leisure is a normal good + + align:start position:0% +effects when Leisure is a normal good + + + align:start position:0% +effects when Leisure is a normal good +okay that's the key lesson from last + + align:start position:0% +okay that's the key lesson from last + + + align:start position:0% +okay that's the key lesson from last +lecture is that even when Leisure a + + align:start position:0% +lecture is that even when Leisure a + + + align:start position:0% +lecture is that even when Leisure a +normal good income effects offset + + align:start position:0% +normal good income effects offset + + + align:start position:0% +normal good income effects offset +substitution effects so we don't know + + align:start position:0% +substitution effects so we don't know + + + align:start position:0% +substitution effects so we don't know +the shape of supply curve that said + + align:start position:0% +the shape of supply curve that said + + + align:start position:0% +the shape of supply curve that said +we're going to pretty much for the rest + + align:start position:0% +we're going to pretty much for the rest + + + align:start position:0% +we're going to pretty much for the rest +of the semester assume upward sloping + + align:start position:0% +of the semester assume upward sloping + + + align:start position:0% +of the semester assume upward sloping +labor Supply curves we're going to + + align:start position:0% +labor Supply curves we're going to + + + align:start position:0% +labor Supply curves we're going to +pretty much assume substitution effects + + align:start position:0% +pretty much assume substitution effects + + + align:start position:0% +pretty much assume substitution effects +offset income effects because they hell + + align:start position:0% +offset income effects because they hell + + + align:start position:0% +offset income effects because they hell +of a lot each to work with it's a mess + + align:start position:0% +of a lot each to work with it's a mess + + + align:start position:0% +of a lot each to work with it's a mess +when they both slope down so we're + + align:start position:0% +when they both slope down so we're + + + align:start position:0% +when they both slope down so we're +pretty much going to assume that + + align:start position:0% +pretty much going to assume that + + + align:start position:0% +pretty much going to assume that +substitution effects Dominate and the + + align:start position:0% +substitution effects Dominate and the + + + align:start position:0% +substitution effects Dominate and the +labor supply curve is upward sloping so + + align:start position:0% +labor supply curve is upward sloping so + + + align:start position:0% +labor supply curve is upward sloping so +here for example we have a labor supply + + align:start position:0% +here for example we have a labor supply + + + align:start position:0% +here for example we have a labor supply +curve um uh of the + + align:start position:0% +curve um uh of the + + + align:start position:0% +curve um uh of the +form uh that uh labor equals um uh wus + + align:start position:0% +form uh that uh labor equals um uh wus + + + align:start position:0% +form uh that uh labor equals um uh wus +10 so a higher wage leads to more labor + + align:start position:0% +10 so a higher wage leads to more labor + + + align:start position:0% +10 so a higher wage leads to more labor +Supply okay so this uh uh so a higher + + align:start position:0% +Supply okay so this uh uh so a higher + + + align:start position:0% +Supply okay so this uh uh so a higher +wage leads to more labor SL it should be + + align:start position:0% +wage leads to more labor SL it should be + + + align:start position:0% +wage leads to more labor SL it should be +L equal 70 so this is the demand curve + + align:start position:0% +L equal 70 so this is the demand curve + + + align:start position:0% +L equal 70 so this is the demand curve +the demand curve is L equal 70 minus W + + align:start position:0% +the demand curve is L equal 70 minus W + + + align:start position:0% +the demand curve is L equal 70 minus W +the supply curve is uh Lal wus 10 so to + + align:start position:0% +the supply curve is uh Lal wus 10 so to + + + align:start position:0% +the supply curve is uh Lal wus 10 so to +solve for equilibrium we simply set + + align:start position:0% +solve for equilibrium we simply set + + + align:start position:0% +solve for equilibrium we simply set +those equal we know how to do that now + + align:start position:0% +those equal we know how to do that now + + + align:start position:0% +those equal we know how to do that now +and you find the equilibrium is at 30 + + align:start position:0% +and you find the equilibrium is at 30 + + + align:start position:0% +and you find the equilibrium is at 30 +units of Labor with a wage of 40 that's + + align:start position:0% +units of Labor with a wage of 40 that's + + + align:start position:0% +units of Labor with a wage of 40 that's +the point at which firms are happy to + + align:start position:0% +the point at which firms are happy to + + + align:start position:0% +the point at which firms are happy to +hire workers and workers are happy to + + align:start position:0% +hire workers and workers are happy to + + + align:start position:0% +hire workers and workers are happy to +work so it's the same kind of + + align:start position:0% +work so it's the same kind of + + + align:start position:0% +work so it's the same kind of +equilibrium of goods markets + + align:start position:0% +equilibrium of goods markets + + + align:start position:0% +equilibrium of goods markets +now it's just in a factor market + + align:start position:0% +now it's just in a factor market + + + align:start position:0% +now it's just in a factor market +okay now let's ask what happens when we + + align:start position:0% +okay now let's ask what happens when we + + + align:start position:0% +okay now let's ask what happens when we +add a minimum + + align:start position:0% +add a minimum + + + align:start position:0% +add a minimum +wage what happens we add a minimum wage + + align:start position:0% +wage what happens we add a minimum wage + + + align:start position:0% +wage what happens we add a minimum wage +which is a standard labor market + + align:start position:0% +which is a standard labor market + + + align:start position:0% +which is a standard labor market +intervention all around the world okay + + align:start position:0% +intervention all around the world okay + + + align:start position:0% +intervention all around the world okay +some of you may even enjoyed minimum + + align:start position:0% +some of you may even enjoyed minimum + + + align:start position:0% +some of you may even enjoyed minimum +wage jobs at some point in your past + + align:start position:0% +wage jobs at some point in your past + + + align:start position:0% +wage jobs at some point in your past +lives or hopefully not in your future + + align:start position:0% +lives or hopefully not in your future + + + align:start position:0% +lives or hopefully not in your future +lives but some point in your past lives + + align:start position:0% +lives but some point in your past lives + + + align:start position:0% +lives but some point in your past lives +uh it's a common feature of the + + align:start position:0% +uh it's a common feature of the + + + align:start position:0% +uh it's a common feature of the +developed worlds have minimum wages the + + align:start position:0% +developed worlds have minimum wages the + + + align:start position:0% +developed worlds have minimum wages the +way minimum wage work is the government + + align:start position:0% +way minimum wage work is the government + + + align:start position:0% +way minimum wage work is the government +just sets a wage floor below which + + align:start position:0% +just sets a wage floor below which + + + align:start position:0% +just sets a wage floor below which +employers cannot pay their employees + + align:start position:0% +employers cannot pay their employees + + + align:start position:0% +employers cannot pay their employees +they set a wage floor so for example + + align:start position:0% +they set a wage floor so for example + + + align:start position:0% +they set a wage floor so for example +imagine the government came in and set a + + align:start position:0% +imagine the government came in and set a + + + align:start position:0% +imagine the government came in and set a +wage floor of 50 set a minimum wage of + + align:start position:0% +wage floor of 50 set a minimum wage of + + + align:start position:0% +wage floor of 50 set a minimum wage of +50 above the market equilibrium + + align:start position:0% +50 above the market equilibrium + + + align:start position:0% +50 above the market equilibrium +wage + + align:start position:0% +wage + + + align:start position:0% +wage +okay so the new equilibrium + + align:start position:0% +okay so the new equilibrium + + + align:start position:0% +okay so the new equilibrium +now is the new outcome the new market + + align:start position:0% +now is the new outcome the new market + + + align:start position:0% +now is the new outcome the new market +outcome is actually at 0 two + + align:start position:0% +outcome is actually at 0 two + + + align:start position:0% +outcome is actually at 0 two +why well because that higher wage firms + + align:start position:0% +why well because that higher wage firms + + + align:start position:0% +why well because that higher wage firms +want to hire fewer + + align:start position:0% +want to hire fewer + + + align:start position:0% +want to hire fewer +workers it doesn't matter what workers + + align:start position:0% +workers it doesn't matter what workers + + + align:start position:0% +workers it doesn't matter what workers +want there's no jobs for them so firms + + align:start position:0% +want there's no jobs for them so firms + + + align:start position:0% +want there's no jobs for them so firms +say fine if that higher wage I only want + + align:start position:0% +say fine if that higher wage I only want + + + align:start position:0% +say fine if that higher wage I only want + + align:start position:0% + + + align:start position:0% +workers workers say well gee at that + + align:start position:0% +workers workers say well gee at that + + + align:start position:0% +workers workers say well gee at that +higher wage I want to work actually uh I + + align:start position:0% +higher wage I want to work actually uh I + + + align:start position:0% +higher wage I want to work actually uh I +want to work much more than + + align:start position:0% +want to work much more than + + + align:start position:0% +want to work much more than +that okay um Andrew in the future uh + + align:start position:0% +that okay um Andrew in the future uh + + + align:start position:0% +that okay um Andrew in the future uh +diagram we should have the Y inter the x + + align:start position:0% +diagram we should have the Y inter the x + + + align:start position:0% +diagram we should have the Y inter the x +intercept for the excess Supply um they + + align:start position:0% +intercept for the excess Supply um they + + + align:start position:0% +intercept for the excess Supply um they +want to work much more than that so you + + align:start position:0% +want to work much more than that so you + + + align:start position:0% +want to work much more than that so you +end up with an excess supply of + + align:start position:0% +end up with an excess supply of + + + align:start position:0% +end up with an excess supply of +labor now when we talked about supply + + align:start position:0% +labor now when we talked about supply + + + align:start position:0% +labor now when we talked about supply +and demand equilibrium we talked about + + align:start position:0% +and demand equilibrium we talked about + + + align:start position:0% +and demand equilibrium we talked about +us how disequilibrium outcomes resolve + + align:start position:0% +us how disequilibrium outcomes resolve + + + align:start position:0% +us how disequilibrium outcomes resolve +themselves through Market adjustments + + align:start position:0% +themselves through Market adjustments + + + align:start position:0% +themselves through Market adjustments +well here this disequilibrium outcome + + align:start position:0% +well here this disequilibrium outcome + + + align:start position:0% +well here this disequilibrium outcome +cannot resolve itself the market can't + + align:start position:0% +cannot resolve itself the market can't + + + align:start position:0% +cannot resolve itself the market can't +adjust the Market's stuck because of the + + align:start position:0% +adjust the Market's stuck because of the + + + align:start position:0% +adjust the Market's stuck because of the +regulation so we end up in a situation + + align:start position:0% +regulation so we end up in a situation + + + align:start position:0% +regulation so we end up in a situation +we're out of equilibrium we have excess + + align:start position:0% +we're out of equilibrium we have excess + + + align:start position:0% +we're out of equilibrium we have excess +Supply okay in in in layman's terms we + + align:start position:0% +Supply okay in in in layman's terms we + + + align:start position:0% +Supply okay in in in layman's terms we +call that + + align:start position:0% +call that + + + align:start position:0% +call that +unemployment we end up with unemployment + + align:start position:0% +unemployment we end up with unemployment + + + align:start position:0% +unemployment we end up with unemployment +we end up with people who want to work + + align:start position:0% +we end up with people who want to work + + + align:start position:0% +we end up with people who want to work +but can't + + align:start position:0% +but can't + + + align:start position:0% +but can't +work okay and that causes an + + align:start position:0% +work okay and that causes an + + + align:start position:0% +work okay and that causes an +inefficiency or dead weight loss you see + + align:start position:0% +inefficiency or dead weight loss you see + + + align:start position:0% +inefficiency or dead weight loss you see +before the + + align:start position:0% +before the + + + align:start position:0% +before the +policy worker + + align:start position:0% +policy worker + + + align:start position:0% +policy worker +Surplus okay was um or I'm sorry firm + + align:start position:0% +Surplus okay was um or I'm sorry firm + + + align:start position:0% +Surplus okay was um or I'm sorry firm +Surplus I'm sorry for the policy firm + + align:start position:0% +Surplus I'm sorry for the policy firm + + + align:start position:0% +Surplus I'm sorry for the policy firm +Surplus cuz firms the consumers here was + + align:start position:0% +Surplus cuz firms the consumers here was + + + align:start position:0% +Surplus cuz firms the consumers here was +a plus b plus C that was the consumer + + align:start position:0% +a plus b plus C that was the consumer + + + align:start position:0% +a plus b plus C that was the consumer +surplus or in this case consumers are + + align:start position:0% +surplus or in this case consumers are + + + align:start position:0% +surplus or in this case consumers are +firms they really call that more the + + align:start position:0% +firms they really call that more the + + + align:start position:0% +firms they really call that more the +demander Surplus the supplier Surplus + + align:start position:0% +demander Surplus the supplier Surplus + + + align:start position:0% +demander Surplus the supplier Surplus +was D plus e with the minimum wage we've + + align:start position:0% +was D plus e with the minimum wage we've + + + align:start position:0% +was D plus e with the minimum wage we've +now transferred the area + + align:start position:0% +now transferred the area + + + align:start position:0% +now transferred the area +B from firms to workers so the firm + + align:start position:0% +B from firms to workers so the firm + + + align:start position:0% +B from firms to workers so the firm +Surplus this the demander Surplus has + + align:start position:0% +Surplus this the demander Surplus has + + + align:start position:0% +Surplus this the demander Surplus has +fallen all the way to + + align:start position:0% +fallen all the way to + + + align:start position:0% +fallen all the way to +a so we've transferred the area B but + + align:start position:0% +a so we've transferred the area B but + + + align:start position:0% +a so we've transferred the area B but +we've created in doing so a dead weight + + align:start position:0% +we've created in doing so a dead weight + + + align:start position:0% +we've created in doing so a dead weight +loss of C plus a + + align:start position:0% +loss of C plus a + + + align:start position:0% +loss of C plus a +standard kind of welfare analys we've + + align:start position:0% +standard kind of welfare analys we've + + + align:start position:0% +standard kind of welfare analys we've +done so several times before now okay so + + align:start position:0% +done so several times before now okay so + + + align:start position:0% +done so several times before now okay so +what we've done with this policy is + + align:start position:0% +what we've done with this policy is + + + align:start position:0% +what we've done with this policy is +we've transferred the area + + align:start position:0% +we've transferred the area + + + align:start position:0% +we've transferred the area +B from the demanders who are firms to + + align:start position:0% +B from the demanders who are firms to + + + align:start position:0% +B from the demanders who are firms to +the suppliers who are workers but in + + align:start position:0% +the suppliers who are workers but in + + + align:start position:0% +the suppliers who are workers but in +doing so we've created a deadweight loss + + align:start position:0% +doing so we've created a deadweight loss + + + align:start position:0% +doing so we've created a deadweight loss +C plus e why because those are trades + + align:start position:0% +C plus e why because those are trades + + + align:start position:0% +C plus e why because those are trades +that would be efficient to make they're + + align:start position:0% +that would be efficient to make they're + + + align:start position:0% +that would be efficient to make they're +not being made there are workers that + + align:start position:0% +not being made there are workers that + + + align:start position:0% +not being made there are workers that +would happily + + align:start position:0% +would happily + + + align:start position:0% +would happily +work at a wage below 50 and firms would + + align:start position:0% +work at a wage below 50 and firms would + + + align:start position:0% +work at a wage below 50 and firms would +be happy to H them at a wage below 50 + + align:start position:0% +be happy to H them at a wage below 50 + + + align:start position:0% +be happy to H them at a wage below 50 +but we're not letting that transaction + + align:start position:0% +but we're not letting that transaction + + + align:start position:0% +but we're not letting that transaction +happen that's wasted economic efficiency + + align:start position:0% +happen that's wasted economic efficiency + + + align:start position:0% +happen that's wasted economic efficiency +or dead weight + + align:start position:0% +or dead weight + + + align:start position:0% +or dead weight +loss this is the pretty standard an of + + align:start position:0% +loss this is the pretty standard an of + + + align:start position:0% +loss this is the pretty standard an of +minimum wage and this says that well + + align:start position:0% +minimum wage and this says that well + + + align:start position:0% +minimum wage and this says that well +look when you put a minimum wage you get + + align:start position:0% +look when you put a minimum wage you get + + + align:start position:0% +look when you put a minimum wage you get +a + + align:start position:0% +a + + + align:start position:0% +a +trade-off you get a transfer to workers + + align:start position:0% +trade-off you get a transfer to workers + + + align:start position:0% +trade-off you get a transfer to workers +which you may like but you create a dead + + align:start position:0% +which you may like but you create a dead + + + align:start position:0% +which you may like but you create a dead +weight loss because you create + + align:start position:0% +weight loss because you create + + + align:start position:0% +weight loss because you create +unemployment but actually starting about + + align:start position:0% +unemployment but actually starting about + + + align:start position:0% +unemployment but actually starting about +30 years ago research started finding + + align:start position:0% +30 years ago research started finding + + + align:start position:0% +30 years ago research started finding +that minimum wages didn't cause + + align:start position:0% +that minimum wages didn't cause + + + align:start position:0% +that minimum wages didn't cause +unemployment actually some research + + align:start position:0% +unemployment actually some research + + + align:start position:0% +unemployment actually some research +studies suggest you put a minimum wage + + align:start position:0% +studies suggest you put a minimum wage + + + align:start position:0% +studies suggest you put a minimum wage +employment goes + + align:start position:0% +employment goes + + + align:start position:0% +employment goes +up but certainly there was very little + + align:start position:0% +up but certainly there was very little + + + align:start position:0% +up but certainly there was very little +evidence that goes + + align:start position:0% +evidence that goes + + + align:start position:0% +evidence that goes +down this was quite striking because how + + align:start position:0% +down this was quite striking because how + + + align:start position:0% +down this was quite striking because how +could that happen now one way it could + + align:start position:0% +could that happen now one way it could + + + align:start position:0% +could that happen now one way it could +happen of course could be if the demand + + align:start position:0% +happen of course could be if the demand + + + align:start position:0% +happen of course could be if the demand +curve was perfectly + + align:start position:0% +curve was perfectly + + + align:start position:0% +curve was perfectly +inelastic then a minimum wage would not + + align:start position:0% +inelastic then a minimum wage would not + + + align:start position:0% +inelastic then a minimum wage would not +lower employment + + align:start position:0% +lower employment + + + align:start position:0% +lower employment +you can see that in this graph it's I + + align:start position:0% +you can see that in this graph it's I + + + align:start position:0% +you can see that in this graph it's I +haven't drawn this out but you see the + + align:start position:0% +haven't drawn this out but you see the + + + align:start position:0% +haven't drawn this out but you see the +162 imagine taking that blue line and + + align:start position:0% +162 imagine taking that blue line and + + + align:start position:0% +162 imagine taking that blue line and +making it vertical you'll see the + + align:start position:0% +making it vertical you'll see the + + + align:start position:0% +making it vertical you'll see the +minimum wage wouldn't cause unemployment + + align:start position:0% +minimum wage wouldn't cause unemployment + + + align:start position:0% +minimum wage wouldn't cause unemployment +so one thing that could be going on is + + align:start position:0% +so one thing that could be going on is + + + align:start position:0% +so one thing that could be going on is +demand could be perfectly in elastic but + + align:start position:0% +demand could be perfectly in elastic but + + + align:start position:0% +demand could be perfectly in elastic but +in fact there's lots of studies which + + align:start position:0% +in fact there's lots of studies which + + + align:start position:0% +in fact there's lots of studies which +say that's not true demand for labor is + + align:start position:0% +say that's not true demand for labor is + + + align:start position:0% +say that's not true demand for labor is +not perfectly in elastic so that can't + + align:start position:0% +not perfectly in elastic so that can't + + + align:start position:0% +not perfectly in elastic so that can't +be the explanation so we said an + + align:start position:0% +be the explanation so we said an + + + align:start position:0% +be the explanation so we said an +alternative explanation which is that + + align:start position:0% +alternative explanation which is that + + + align:start position:0% +alternative explanation which is that +just like Goods markets can be + + align:start position:0% +just like Goods markets can be + + + align:start position:0% +just like Goods markets can be +non-competitive labor markets can also + + align:start position:0% +non-competitive labor markets can also + + + align:start position:0% +non-competitive labor markets can also +be non-competitive + + align:start position:0% +be non-competitive + + + align:start position:0% +be non-competitive +and so we think the explanation is + + align:start position:0% +and so we think the explanation is + + + align:start position:0% +and so we think the explanation is +non-competitive labor + + align:start position:0% +non-competitive labor + + + align:start position:0% +non-competitive labor +markets okay so when we when we thought + + align:start position:0% +markets okay so when we when we thought + + + align:start position:0% +markets okay so when we when we thought +about firms selling Goods we said look + + align:start position:0% +about firms selling Goods we said look + + + align:start position:0% +about firms selling Goods we said look +at a competitive market firms face + + align:start position:0% +at a competitive market firms face + + + align:start position:0% +at a competitive market firms face +perfectly elastic demand any given firm + + align:start position:0% +perfectly elastic demand any given firm + + + align:start position:0% +perfectly elastic demand any given firm +faces perfectly elastic + + align:start position:0% +faces perfectly elastic + + + align:start position:0% +faces perfectly elastic +demand okay well + + align:start position:0% +demand okay well + + + align:start position:0% +demand okay well +likewise when we think about a firm + + align:start position:0% +likewise when we think about a firm + + + align:start position:0% +likewise when we think about a firm +hiring workers we think that in a we if + + align:start position:0% +hiring workers we think that in a we if + + + align:start position:0% +hiring workers we think that in a we if +labor markets are competitive + + align:start position:0% +labor markets are competitive + + + align:start position:0% +labor markets are competitive +any given firm faed a perfectly elastic + + align:start position:0% +any given firm faed a perfectly elastic + + + align:start position:0% +any given firm faed a perfectly elastic +supply curve think about the intuition + + align:start position:0% +supply curve think about the intuition + + + align:start position:0% +supply curve think about the intuition +the interest perfectly competitive + + align:start position:0% +the interest perfectly competitive + + + align:start position:0% +the interest perfectly competitive +market is look if I'm selling chachis + + align:start position:0% +market is look if I'm selling chachis + + + align:start position:0% +market is look if I'm selling chachis +next to the other guy selling + + align:start position:0% +next to the other guy selling + + + align:start position:0% +next to the other guy selling +chachis then I can't raise my price + + align:start position:0% +chachis then I can't raise my price + + + align:start position:0% +chachis then I can't raise my price +above or below his because if I raise it + + align:start position:0% +above or below his because if I raise it + + + align:start position:0% +above or below his because if I raise it +above I'll sell zero below I'll sell I + + align:start position:0% +above I'll sell zero below I'll sell I + + + align:start position:0% +above I'll sell zero below I'll sell I +won't I won't be able to meet + + align:start position:0% +won't I won't be able to meet + + + align:start position:0% +won't I won't be able to meet +demand well it's the same thing when + + align:start position:0% +demand well it's the same thing when + + + align:start position:0% +demand well it's the same thing when +hiring workers a perfectly competitive + + align:start position:0% +hiring workers a perfectly competitive + + + align:start position:0% +hiring workers a perfectly competitive +market imagine a perfectly competitive + + align:start position:0% +market imagine a perfectly competitive + + + align:start position:0% +market imagine a perfectly competitive +labor market which is fast food + + align:start position:0% +labor market which is fast food + + + align:start position:0% +labor market which is fast food +workers okay there's a bunch of fast + + align:start position:0% +workers okay there's a bunch of fast + + + align:start position:0% +workers okay there's a bunch of fast +food restaurants near each other if + + align:start position:0% +food restaurants near each other if + + + align:start position:0% +food restaurants near each other if +McDonald's pays 50 cents more than + + align:start position:0% +McDonald's pays 50 cents more than + + + align:start position:0% +McDonald's pays 50 cents more than +Burger King everyone leaves Burger King + + align:start position:0% +Burger King everyone leaves Burger King + + + align:start position:0% +Burger King everyone leaves Burger King +and works at McDonald's if Burger King + + align:start position:0% +and works at McDonald's if Burger King + + + align:start position:0% +and works at McDonald's if Burger King +pays 50 cents more than McDonald's vice + + align:start position:0% +pays 50 cents more than McDonald's vice + + + align:start position:0% +pays 50 cents more than McDonald's vice +versa so you have essentially each firm + + align:start position:0% +versa so you have essentially each firm + + + align:start position:0% +versa so you have essentially each firm +faces a flat supply curve because + + align:start position:0% +faces a flat supply curve because + + + align:start position:0% +faces a flat supply curve because +workers can just move it's an easy + + align:start position:0% +workers can just move it's an easy + + + align:start position:0% +workers can just move it's an easy +substitution between them just like it's + + align:start position:0% +substitution between them just like it's + + + align:start position:0% +substitution between them just like it's +EAS a substitute between statues of the + + align:start position:0% +EAS a substitute between statues of the + + + align:start position:0% +EAS a substitute between statues of the +eiel tower little mini statues it's easy + + align:start position:0% +eiel tower little mini statues it's easy + + + align:start position:0% +eiel tower little mini statues it's easy +substitute between working mcdonal and + + align:start position:0% +substitute between working mcdonal and + + + align:start position:0% +substitute between working mcdonal and +Burger King it's the same job and + + align:start position:0% +Burger King it's the same job and + + + align:start position:0% +Burger King it's the same job and +they're near each + + align:start position:0% +they're near each + + + align:start position:0% +they're near each +other okay however + + align:start position:0% +other okay however + + + align:start position:0% +other okay however +what we've realized is that may in fact + + align:start position:0% +what we've realized is that may in fact + + + align:start position:0% +what we've realized is that may in fact +not be + + align:start position:0% +not be + + + align:start position:0% +not be +true what if just like Goods markets can + + align:start position:0% +true what if just like Goods markets can + + + align:start position:0% +true what if just like Goods markets can +be + + align:start position:0% +be + + + align:start position:0% +be +non-competitive what if labor markets + + align:start position:0% +non-competitive what if labor markets + + + align:start position:0% +non-competitive what if labor markets +can be + + align:start position:0% +can be + + + align:start position:0% +can be +non-competitive remember the assumptions + + align:start position:0% +non-competitive remember the assumptions + + + align:start position:0% +non-competitive remember the assumptions +we required for a perfectly competitive + + align:start position:0% +we required for a perfectly competitive + + + align:start position:0% +we required for a perfectly competitive +Goods Market we required perfect + + align:start position:0% +Goods Market we required perfect + + + align:start position:0% +Goods Market we required perfect +information and no transaction costs and + + align:start position:0% +information and no transaction costs and + + + align:start position:0% +information and no transaction costs and +all Goods being the same well for a + + align:start position:0% +all Goods being the same well for a + + + align:start position:0% +all Goods being the same well for a +perfectly competitive labor market the + + align:start position:0% +perfectly competitive labor market the + + + align:start position:0% +perfectly competitive labor market the +same requirements are in place + + align:start position:0% +same requirements are in place + + + align:start position:0% +same requirements are in place +you need perfect + + align:start position:0% +you need perfect + + + align:start position:0% +you need perfect +information you need no transaction + + align:start position:0% +information you need no transaction + + + align:start position:0% +information you need no transaction +costs and all jobs to be the same well + + align:start position:0% +costs and all jobs to be the same well + + + align:start position:0% +costs and all jobs to be the same well +that's not true in particular the first + + align:start position:0% +that's not true in particular the first + + + align:start position:0% +that's not true in particular the first +isn't true we don't have perfect + + align:start position:0% +isn't true we don't have perfect + + + align:start position:0% +isn't true we don't have perfect +information because jobs don't always + + align:start position:0% +information because jobs don't always + + + align:start position:0% +information because jobs don't always +post their wages typically don't post + + align:start position:0% +post their wages typically don't post + + + align:start position:0% +post their wages typically don't post +their wages and typically you don't know + + align:start position:0% +their wages and typically you don't know + + + align:start position:0% +their wages and typically you don't know +what you can make in another + + align:start position:0% +what you can make in another + + + align:start position:0% +what you can make in another +firm okay once you don't know what you + + align:start position:0% +firm okay once you don't know what you + + + align:start position:0% +firm okay once you don't know what you +can make in another firm once it's + + align:start position:0% +can make in another firm once it's + + + align:start position:0% +can make in another firm once it's +costly to learn that that's a + + align:start position:0% +costly to learn that that's a + + + align:start position:0% +costly to learn that that's a +transaction cost that interferes + + align:start position:0% +transaction cost that interferes + + + align:start position:0% +transaction cost that interferes +okay that's one form of transaction + + align:start position:0% +okay that's one form of transaction + + + align:start position:0% +okay that's one form of transaction +costs that could interfere what we think + + align:start position:0% +costs that could interfere what we think + + + align:start position:0% +costs that could interfere what we think +is a fairly competitive + + align:start position:0% +is a fairly competitive + + + align:start position:0% +is a fairly competitive +market okay now let's go further let's + + align:start position:0% +market okay now let's go further let's + + + align:start position:0% +market okay now let's go further let's +think about the most extreme case which + + align:start position:0% +think about the most extreme case which + + + align:start position:0% +think about the most extreme case which +was the old mining towns we used to have + + align:start position:0% +was the old mining towns we used to have + + + align:start position:0% +was the old mining towns we used to have +in the West in the US in the US the way + + align:start position:0% +in the West in the US in the US the way + + + align:start position:0% +in the West in the US in the US the way +it work is you discovered gold you'd set + + align:start position:0% +it work is you discovered gold you'd set + + + align:start position:0% +it work is you discovered gold you'd set +up a town to around the gold mine and + + align:start position:0% +up a town to around the gold mine and + + + align:start position:0% +up a town to around the gold mine and +everyone in that town would work in the + + align:start position:0% +everyone in that town would work in the + + + align:start position:0% +everyone in that town would work in the +gold mine or they would work selling + + align:start position:0% +gold mine or they would work selling + + + align:start position:0% +gold mine or they would work selling +stuff to worked in the gold mine okay + + align:start position:0% +stuff to worked in the gold mine okay + + + align:start position:0% +stuff to worked in the gold mine okay +well in that case you definitely didn't + + align:start position:0% +well in that case you definitely didn't + + + align:start position:0% +well in that case you definitely didn't +face a competitive labor market because + + align:start position:0% +face a competitive labor market because + + + align:start position:0% +face a competitive labor market because +that was the only place to work there + + align:start position:0% +that was the only place to work there + + + align:start position:0% +that was the only place to work there +was one employer the gold + + align:start position:0% +was one employer the gold + + + align:start position:0% +was one employer the gold +mine and they had and if you want to + + align:start position:0% +mine and they had and if you want to + + + align:start position:0% +mine and they had and if you want to +work you had to work for that one + + align:start position:0% +work you had to work for that one + + + align:start position:0% +work you had to work for that one +employer so instead of the case of a + + align:start position:0% +employer so instead of the case of a + + + align:start position:0% +employer so instead of the case of a +monopoly we had a case of a + + align:start position:0% +monopoly we had a case of a + + + align:start position:0% +monopoly we had a case of a +monopsony a monopsony a + + align:start position:0% +monopsony a monopsony a + + + align:start position:0% +monopsony a monopsony a +monopoly is when only one firm sells the + + align:start position:0% +monopoly is when only one firm sells the + + + align:start position:0% +monopoly is when only one firm sells the +good a + + align:start position:0% +good a + + + align:start position:0% +good a +monopsony is when only one firm hires + + align:start position:0% +monopsony is when only one firm hires + + + align:start position:0% +monopsony is when only one firm hires +the workers + + align:start position:0% + + + + align:start position:0% + +okay let's suppose further let's just s + + align:start position:0% +okay let's suppose further let's just s + + + align:start position:0% +okay let's suppose further let's just s +is having a bunch of Gold Mine Workers + + align:start position:0% +is having a bunch of Gold Mine Workers + + + align:start position:0% +is having a bunch of Gold Mine Workers +let's suppose further that just as we + + align:start position:0% +let's suppose further that just as we + + + align:start position:0% +let's suppose further that just as we +assume initially the monopolies can't + + align:start position:0% +assume initially the monopolies can't + + + align:start position:0% +assume initially the monopolies can't +price + + align:start position:0% +price + + + align:start position:0% +price +discriminate let's assume monopsonies + + align:start position:0% +discriminate let's assume monopsonies + + + align:start position:0% +discriminate let's assume monopsonies +can't wage discriminate this is actually + + align:start position:0% +can't wage discriminate this is actually + + + align:start position:0% +can't wage discriminate this is actually +kind of a more reasonable assumption it + + align:start position:0% +kind of a more reasonable assumption it + + + align:start position:0% +kind of a more reasonable assumption it +was always sort of weird to say why + + align:start position:0% +was always sort of weird to say why + + + align:start position:0% +was always sort of weird to say why +could monopolis charge different people + + align:start position:0% +could monopolis charge different people + + + align:start position:0% +could monopolis charge different people +different prices it's a more reasonable + + align:start position:0% +different prices it's a more reasonable + + + align:start position:0% +different prices it's a more reasonable +sub to think firms can't pay similar + + align:start position:0% +sub to think firms can't pay similar + + + align:start position:0% +sub to think firms can't pay similar +worker different way wages they'd be + + align:start position:0% +worker different way wages they'd be + + + align:start position:0% +worker different way wages they'd be +pissed right it's sort of you know if if + + align:start position:0% +pissed right it's sort of you know if if + + + align:start position:0% +pissed right it's sort of you know if if +if you're paying two Works doing the + + align:start position:0% +if you're paying two Works doing the + + + align:start position:0% +if you're paying two Works doing the +same job different wages they're going + + align:start position:0% +same job different wages they're going + + + align:start position:0% +same job different wages they're going +to get upset people care about Equity + + align:start position:0% +to get upset people care about Equity + + + align:start position:0% +to get upset people care about Equity +it's sort of more reasonable think for + + align:start position:0% +it's sort of more reasonable think for + + + align:start position:0% +it's sort of more reasonable think for +the same job you sort of have to pay the + + align:start position:0% +the same job you sort of have to pay the + + + align:start position:0% +the same job you sort of have to pay the +same wage I think that's a much sort of + + align:start position:0% +same wage I think that's a much sort of + + + align:start position:0% +same wage I think that's a much sort of +more reasonable assumption than it is a + + align:start position:0% +more reasonable assumption than it is a + + + align:start position:0% +more reasonable assumption than it is a +monopoly + + align:start position:0% +monopoly + + + align:start position:0% +monopoly +case okay I mean you can pay managers + + align:start position:0% +case okay I mean you can pay managers + + + align:start position:0% +case okay I mean you can pay managers +more than M workers but it's sort of + + align:start position:0% +more than M workers but it's sort of + + + align:start position:0% +more than M workers but it's sort of +reasonable to think you kind of have to + + align:start position:0% +reasonable to think you kind of have to + + + align:start position:0% +reasonable to think you kind of have to +pay all the M workers the same + + align:start position:0% +pay all the M workers the same + + + align:start position:0% +pay all the M workers the same +thing what that means is that just as + + align:start position:0% +thing what that means is that just as + + + align:start position:0% +thing what that means is that just as +when you're a + + align:start position:0% +when you're a + + + align:start position:0% +when you're a +monopoly lowering your price might hurt + + align:start position:0% +monopoly lowering your price might hurt + + + align:start position:0% +monopoly lowering your price might hurt +your profits through the poisoning + + align:start position:0% +your profits through the poisoning + + + align:start position:0% +your profits through the poisoning +effect when your M + + align:start position:0% +effect when your M + + + align:start position:0% +effect when your M +monopsony raising the wage will hurt + + align:start position:0% +monopsony raising the wage will hurt + + + align:start position:0% +monopsony raising the wage will hurt +your profits through an equivalent + + align:start position:0% +your profits through an equivalent + + + align:start position:0% +your profits through an equivalent +poisoning + + align:start position:0% +poisoning + + + align:start position:0% +poisoning +effect so let's think about the firm's + + align:start position:0% +effect so let's think about the firm's + + + align:start position:0% +effect so let's think about the firm's +decision okay the firm wants to set the + + align:start position:0% +decision okay the firm wants to set the + + + align:start position:0% +decision okay the firm wants to set the +marginal cost of the next worker equal + + align:start position:0% +marginal cost of the next worker equal + + + align:start position:0% +marginal cost of the next worker equal +to the marginal benefit of the next + + align:start position:0% +to the marginal benefit of the next + + + align:start position:0% +to the marginal benefit of the next +worker okay what is the marginal + + align:start position:0% +worker okay what is the marginal + + + align:start position:0% +worker okay what is the marginal +benefit well the marginal benefit is + + align:start position:0% +benefit well the marginal benefit is + + + align:start position:0% +benefit well the marginal benefit is +still the marginal revenue product of + + align:start position:0% +still the marginal revenue product of + + + align:start position:0% +still the marginal revenue product of +labor that hasn't changed that's true + + align:start position:0% +labor that hasn't changed that's true + + + align:start position:0% +labor that hasn't changed that's true +regardless of the market the next worker + + align:start position:0% +regardless of the market the next worker + + + align:start position:0% +regardless of the market the next worker +produces the next marginal revenue + + align:start position:0% +produces the next marginal revenue + + + align:start position:0% +produces the next marginal revenue +produc the marginal product of labor + + align:start position:0% +produc the marginal product of labor + + + align:start position:0% +produc the marginal product of labor +what changes the marginal + + align:start position:0% +what changes the marginal + + + align:start position:0% +what changes the marginal +cost before the marginal cost was the + + align:start position:0% +cost before the marginal cost was the + + + align:start position:0% +cost before the marginal cost was the +wage in a perfectly competitive labor + + align:start position:0% +wage in a perfectly competitive labor + + + align:start position:0% +wage in a perfectly competitive labor +market I didn't say last time I was + + align:start position:0% +market I didn't say last time I was + + + align:start position:0% +market I didn't say last time I was +assuming that but I was in a perfectly + + align:start position:0% +assuming that but I was in a perfectly + + + align:start position:0% +assuming that but I was in a perfectly +competitive labor market the wage is the + + align:start position:0% +competitive labor market the wage is the + + + align:start position:0% +competitive labor market the wage is the +cost but in a monop market that's no + + align:start position:0% +cost but in a monop market that's no + + + align:start position:0% +cost but in a monop market that's no +longer true and to see that want to say + + align:start position:0% +longer true and to see that want to say + + + align:start position:0% +longer true and to see that want to say +what's the marginal cost the mar cost is + + align:start position:0% +what's the marginal cost the mar cost is + + + align:start position:0% +what's the marginal cost the mar cost is +the marginal expenditure to get another + + align:start position:0% +the marginal expenditure to get another + + + align:start position:0% +the marginal expenditure to get another +unit of + + align:start position:0% +unit of + + + align:start position:0% +unit of +Labor well what's the expenditure to get + + align:start position:0% +Labor well what's the expenditure to get + + + align:start position:0% +Labor well what's the expenditure to get +another unit of Labor your expenditure + + align:start position:0% +another unit of Labor your expenditure + + + align:start position:0% +another unit of Labor your expenditure +is your what's your total what's your + + align:start position:0% +is your what's your total what's your + + + align:start position:0% +is your what's your total what's your +total wage Bill I'm sorry what's your + + align:start position:0% +total wage Bill I'm sorry what's your + + + align:start position:0% +total wage Bill I'm sorry what's your +total wage bill it's the wage you pay by + + align:start position:0% +total wage bill it's the wage you pay by + + + align:start position:0% +total wage bill it's the wage you pay by +times the number of workers you have but + + align:start position:0% +times the number of workers you have but + + + align:start position:0% +times the number of workers you have but +the number of workers you have is a + + align:start position:0% +the number of workers you have is a + + + align:start position:0% +the number of workers you have is a +function of the wage you pay right the + + align:start position:0% +function of the wage you pay right the + + + align:start position:0% +function of the wage you pay right the +more you pay the more workers will kind + + align:start position:0% +more you pay the more workers will kind + + + align:start position:0% +more you pay the more workers will kind +of want to work with you so if we + + align:start position:0% +of want to work with you so if we + + + align:start position:0% +of want to work with you so if we +differentiate this and get marginal + + align:start position:0% +differentiate this and get marginal + + + align:start position:0% +differentiate this and get marginal +expenditure which is sort of the firm's + + align:start position:0% +expenditure which is sort of the firm's + + + align:start position:0% +expenditure which is sort of the firm's +marginal cost of hiring another unit of + + align:start position:0% +marginal cost of hiring another unit of + + + align:start position:0% +marginal cost of hiring another unit of +Labor the marginal + + align:start position:0% +Labor the marginal + + + align:start position:0% +Labor the marginal +expenditure is W plus DW DL time + + align:start position:0% + + + + align:start position:0% + +l in other + + align:start position:0% +l in other + + + align:start position:0% +l in other +words it's this term which is positive + + align:start position:0% +words it's this term which is positive + + + align:start position:0% +words it's this term which is positive +the marginal expenditure is the wage + + align:start position:0% +the marginal expenditure is the wage + + + align:start position:0% +the marginal expenditure is the wage +plus this second term which is how much + + align:start position:0% +plus this second term which is how much + + + align:start position:0% +plus this second term which is how much +do you have to raise the wage to get + + align:start position:0% +do you have to raise the wage to get + + + align:start position:0% +do you have to raise the wage to get +another worker + + align:start position:0% +another worker + + + align:start position:0% +another worker +it's a flip side of the poisoning effect + + align:start position:0% +it's a flip side of the poisoning effect + + + align:start position:0% +it's a flip side of the poisoning effect +the poisoning effect was as a monopolist + + align:start position:0% +the poisoning effect was as a monopolist + + + align:start position:0% +the poisoning effect was as a monopolist +if I want to sell one more unit I face a + + align:start position:0% +if I want to sell one more unit I face a + + + align:start position:0% +if I want to sell one more unit I face a +tradeoff I sell the additional unit + + align:start position:0% +tradeoff I sell the additional unit + + + align:start position:0% +tradeoff I sell the additional unit +that's good but I have to lower my price + + align:start position:0% +that's good but I have to lower my price + + + align:start position:0% +that's good but I have to lower my price +to sell it that's bad here if I want to + + align:start position:0% +to sell it that's bad here if I want to + + + align:start position:0% +to sell it that's bad here if I want to +hire one more unit of Labor there's an + + align:start position:0% +hire one more unit of Labor there's an + + + align:start position:0% +hire one more unit of Labor there's an +equivalent tradeoff I get one more + + align:start position:0% +equivalent tradeoff I get one more + + + align:start position:0% +equivalent tradeoff I get one more +worker that's + + align:start position:0% +worker that's + + + align:start position:0% +worker that's +good but I have to pay all my workers + + align:start position:0% +good but I have to pay all my workers + + + align:start position:0% +good but I have to pay all my workers +more to get him that's bad + + align:start position:0% +more to get him that's bad + + + align:start position:0% +more to get him that's bad +why because I can't wage + + align:start position:0% +why because I can't wage + + + align:start position:0% +why because I can't wage +discriminate and it sort of makes sense + + align:start position:0% +discriminate and it sort of makes sense + + + align:start position:0% +discriminate and it sort of makes sense +if I want to expand the number of it's I + + align:start position:0% +if I want to expand the number of it's I + + + align:start position:0% +if I want to expand the number of it's I +once again I think it's much more intive + + align:start position:0% +once again I think it's much more intive + + + align:start position:0% +once again I think it's much more intive +the Monopoly case if I want more workers + + align:start position:0% +the Monopoly case if I want more workers + + + align:start position:0% +the Monopoly case if I want more workers +I got to raise the + + align:start position:0% +I got to raise the + + + align:start position:0% +I got to raise the +wage okay why was this not an issue for + + align:start position:0% +wage okay why was this not an issue for + + + align:start position:0% +wage okay why was this not an issue for +the perfectly competitive firm it's not + + align:start position:0% +the perfectly competitive firm it's not + + + align:start position:0% +the perfectly competitive firm it's not +an issue firm because they faced a + + align:start position:0% +an issue firm because they faced a + + + align:start position:0% +an issue firm because they faced a +perfectly elastic firm labor supply + + align:start position:0% +perfectly elastic firm labor supply + + + align:start position:0% +perfectly elastic firm labor supply +curve workers were different McDonald's + + align:start position:0% +curve workers were different McDonald's + + + align:start position:0% +curve workers were different McDonald's +and Burger King so they could just go + + align:start position:0% +and Burger King so they could just go + + + align:start position:0% +and Burger King so they could just go +back and forth but a a monopsonist + + align:start position:0% +back and forth but a a monopsonist + + + align:start position:0% +back and forth but a a monopsonist +doesn't face that anymore they face the + + align:start position:0% +doesn't face that anymore they face the + + + align:start position:0% +doesn't face that anymore they face the +true market labor supply curve which is + + align:start position:0% +true market labor supply curve which is + + + align:start position:0% +true market labor supply curve which is +not perfectly elastic so to see this + + align:start position:0% +not perfectly elastic so to see this + + + align:start position:0% +not perfectly elastic so to see this +let's go to figure 164 so + + align:start position:0% +let's go to figure 164 so + + + align:start position:0% +let's go to figure 164 so +163 that's a perfectly competitive + + align:start position:0% +163 that's a perfectly competitive + + + align:start position:0% +163 that's a perfectly competitive +case the marginal benefit of hiring + + align:start position:0% +case the marginal benefit of hiring + + + align:start position:0% +case the marginal benefit of hiring +another worker is the marginal revenue + + align:start position:0% +another worker is the marginal revenue + + + align:start position:0% +another worker is the marginal revenue +product of labor 163 the marginal + + align:start position:0% +product of labor 163 the marginal + + + align:start position:0% +product of labor 163 the marginal +benefit the marginal revenue product of + + align:start position:0% +benefit the marginal revenue product of + + + align:start position:0% +benefit the marginal revenue product of +labor the marginal cost is expressed by + + align:start position:0% +labor the marginal cost is expressed by + + + align:start position:0% +labor the marginal cost is expressed by +the wage which is determined by a + + align:start position:0% +the wage which is determined by a + + + align:start position:0% +the wage which is determined by a +perfectly competitive + + align:start position:0% +perfectly competitive + + + align:start position:0% +perfectly competitive +market but 164 is a mopsy now we have + + align:start position:0% +market but 164 is a mopsy now we have + + + align:start position:0% +market but 164 is a mopsy now we have +the same marginal revenue product of + + align:start position:0% +the same marginal revenue product of + + + align:start position:0% +the same marginal revenue product of +labor which we defined as 70 minus L we + + align:start position:0% +labor which we defined as 70 minus L we + + + align:start position:0% +labor which we defined as 70 minus L we +use the same example did before 70 minus + + align:start position:0% +use the same example did before 70 minus + + + align:start position:0% +use the same example did before 70 minus +L uh well we're flipping this so the + + align:start position:0% +L uh well we're flipping this so the + + + align:start position:0% +L uh well we're flipping this so the +marginal so now we can write the + + align:start position:0% +marginal so now we can write the + + + align:start position:0% +marginal so now we can write the +marginal revenue product of labor curve + + align:start position:0% +marginal revenue product of labor curve + + + align:start position:0% +marginal revenue product of labor curve +as simply W equal 70 minus l so just + + align:start position:0% +as simply W equal 70 minus l so just + + + align:start position:0% +as simply W equal 70 minus l so just +inverting + + align:start position:0% + + + + align:start position:0% + +that okay that's that's the firm's + + align:start position:0% +that okay that's that's the firm's + + + align:start position:0% +that okay that's that's the firm's +demand curve or margin product of labor + + align:start position:0% +demand curve or margin product of labor + + + align:start position:0% +demand curve or margin product of labor +curve but what about its marginal + + align:start position:0% +curve but what about its marginal + + + align:start position:0% +curve but what about its marginal +expenditure curve well if you look at + + align:start position:0% +expenditure curve well if you look at + + + align:start position:0% +expenditure curve well if you look at +the supply curve the supply curve was w + + align:start position:0% +the supply curve the supply curve was w + + + align:start position:0% +the supply curve the supply curve was w += l + 10 right so we can now say expend + + align:start position:0% += l + 10 right so we can now say expend + + + align:start position:0% += l + 10 right so we can now say expend +the firm's expenditure + + align:start position:0% +the firm's expenditure + + + align:start position:0% +the firm's expenditure +function labor is W I'm sorry uh the + + align:start position:0% +function labor is W I'm sorry uh the + + + align:start position:0% +function labor is W I'm sorry uh the +firm's expenditure + + align:start position:0% +firm's expenditure + + + align:start position:0% +firm's expenditure +function is L time L + 10 that's its + + align:start position:0% +function is L time L + 10 that's its + + + align:start position:0% +function is L time L + 10 that's its +labor expenditures right stare at that + + align:start position:0% +labor expenditures right stare at that + + + align:start position:0% +labor expenditures right stare at that +for a minute the number of workers times + + align:start position:0% +for a minute the number of workers times + + + align:start position:0% +for a minute the number of workers times +the wage the wage comes from this + + align:start position:0% +the wage the wage comes from this + + + align:start position:0% +the wage the wage comes from this +equation differentiate that with respect + + align:start position:0% +equation differentiate that with respect + + + align:start position:0% +equation differentiate that with respect +to L and what do you + + align:start position:0% +to L and what do you + + + align:start position:0% +to L and what do you +get if you different if you differ + + align:start position:0% +get if you different if you differ + + + align:start position:0% +get if you different if you differ +respect to L you get that you get two + + align:start position:0% +respect to L you get that you get two + + + align:start position:0% +respect to L you get that you get two +you get uh 2 L + + + align:start position:0% +you get uh 2 L + + + + align:start position:0% +you get uh 2 L + +10 and that is the firm's marginal + + align:start position:0% +10 and that is the firm's marginal + + + align:start position:0% +10 and that is the firm's marginal +expenditure + + align:start position:0% +expenditure + + + align:start position:0% +expenditure +curve which is + + align:start position:0% +curve which is + + + align:start position:0% +curve which is +above the F the supply curve as you see + + align:start position:0% +above the F the supply curve as you see + + + align:start position:0% +above the F the supply curve as you see +in figure + + align:start position:0% +in figure + + + align:start position:0% +in figure +164 so what does a monopsonist do the + + align:start position:0% +164 so what does a monopsonist do the + + + align:start position:0% +164 so what does a monopsonist do the +monopsonist set + + align:start position:0% +monopsonist set + + + align:start position:0% +monopsonist set +goes to the point where marginal cost + + align:start position:0% +goes to the point where marginal cost + + + align:start position:0% +goes to the point where marginal cost +equals marginal benefits what's the + + align:start position:0% +equals marginal benefits what's the + + + align:start position:0% +equals marginal benefits what's the +marginal cost the marginal cost is the + + align:start position:0% +marginal cost the marginal cost is the + + + align:start position:0% +marginal cost the marginal cost is the +marginal expenditure curve what's the + + align:start position:0% +marginal expenditure curve what's the + + + align:start position:0% +marginal expenditure curve what's the +marginal benefit the marginal revenue + + align:start position:0% +marginal benefit the marginal revenue + + + align:start position:0% +marginal benefit the marginal revenue +product curve so it says I want to hire + + align:start position:0% +product curve so it says I want to hire + + + align:start position:0% +product curve so it says I want to hire + + align:start position:0% + + + align:start position:0% +workers not the 30 I was hiring in the + + align:start position:0% +workers not the 30 I was hiring in the + + + align:start position:0% +workers not the 30 I was hiring in the +market was competitive but + + align:start position:0% +market was competitive but + + + align:start position:0% +market was competitive but +20 what wage am I going to pay them well + + align:start position:0% +20 what wage am I going to pay them well + + + align:start position:0% +20 what wage am I going to pay them well +just like the monopolist needs to + + align:start position:0% +just like the monopolist needs to + + + align:start position:0% +just like the monopolist needs to +respect the demand curve the monopsonist + + align:start position:0% +respect the demand curve the monopsonist + + + align:start position:0% +respect the demand curve the monopsonist +needs to respect the supply curve so + + align:start position:0% +needs to respect the supply curve so + + + align:start position:0% +needs to respect the supply curve so +ways you can pay them when we read off + + align:start position:0% +ways you can pay them when we read off + + + align:start position:0% +ways you can pay them when we read off +the supply curve you're going to pay + + align:start position:0% +the supply curve you're going to pay + + + align:start position:0% +the supply curve you're going to pay +them 30 instead of + + align:start position:0% +them 30 instead of + + + align:start position:0% +them 30 instead of +40 so what's going on here you're hiring + + align:start position:0% +40 so what's going on here you're hiring + + + align:start position:0% +40 so what's going on here you're hiring +fewer workers at a lower + + align:start position:0% +fewer workers at a lower + + + align:start position:0% +fewer workers at a lower +wage than the equilibrium would dictate + + align:start position:0% +wage than the equilibrium would dictate + + + align:start position:0% +wage than the equilibrium would dictate +why because if you want more workers you + + align:start position:0% +why because if you want more workers you + + + align:start position:0% +why because if you want more workers you +got to raise the wage and that's not + + align:start position:0% +got to raise the wage and that's not + + + align:start position:0% +got to raise the wage and that's not +profitable so if you're if you're at the + + align:start position:0% +profitable so if you're if you're at the + + + align:start position:0% +profitable so if you're if you're at the +point where you're paying 30 to get 20 + + align:start position:0% +point where you're paying 30 to get 20 + + + align:start position:0% +point where you're paying 30 to get 20 +workers and from that point you want to + + align:start position:0% +workers and from that point you want to + + + align:start position:0% +workers and from that point you want to +hire more workers say well look you know + + align:start position:0% +hire more workers say well look you know + + + align:start position:0% +hire more workers say well look you know +even at that point it's you know I'm + + align:start position:0% +even at that point it's you know I'm + + + align:start position:0% +even at that point it's you know I'm +making money on the next + + align:start position:0% +making money on the next + + + align:start position:0% +making money on the next +worker but the problem is to hire that + + align:start position:0% +worker but the problem is to hire that + + + align:start position:0% +worker but the problem is to hire that +next work you have to pay higher wages + + align:start position:0% +next work you have to pay higher wages + + + align:start position:0% +next work you have to pay higher wages +to all your previous workers and it's + + align:start position:0% +to all your previous workers and it's + + + align:start position:0% +to all your previous workers and it's +not worth it this is a hard intuition + + align:start position:0% +not worth it this is a hard intuition + + + align:start position:0% +not worth it this is a hard intuition +but it's the flip side of the poisoning + + align:start position:0% +but it's the flip side of the poisoning + + + align:start position:0% +but it's the flip side of the poisoning +intuition so go back to your Monopoly + + align:start position:0% +intuition so go back to your Monopoly + + + align:start position:0% +intuition so go back to your Monopoly +case and work it through you'll see it's + + align:start position:0% +case and work it through you'll see it's + + + align:start position:0% +case and work it through you'll see it's +all just the + + align:start position:0% +all just the + + + align:start position:0% +all just the +opposite okay now while I need to teach + + align:start position:0% +opposite okay now while I need to teach + + + align:start position:0% +opposite okay now while I need to teach +you the math and the graphs because + + align:start position:0% +you the math and the graphs because + + + align:start position:0% +you the math and the graphs because +that's what we test you on the intuition + + align:start position:0% +that's what we test you on the intuition + + + align:start position:0% +that's what we test you on the intuition +here is actually pretty clear I think + + align:start position:0% +here is actually pretty clear I think + + + align:start position:0% +here is actually pretty clear I think +clearer than the Monopoly case just + + align:start position:0% +clearer than the Monopoly case just + + + align:start position:0% +clearer than the Monopoly case just +think about the intuition for a second + + align:start position:0% +think about the intuition for a second + + + align:start position:0% +think about the intuition for a second +think about me at + + align:start position:0% +think about me at + + + align:start position:0% +think about me at +MIT there's many universities I could + + align:start position:0% +MIT there's many universities I could + + + align:start position:0% +MIT there's many universities I could +work for okay I mean it sound arrogant + + align:start position:0% +work for okay I mean it sound arrogant + + + align:start position:0% +work for okay I mean it sound arrogant +but there's a lot of universities out + + align:start position:0% +but there's a lot of universities out + + + align:start position:0% +but there's a lot of universities out +there presumably some others would want + + align:start position:0% +there presumably some others would want + + + align:start position:0% +there presumably some others would want +to hire me + + align:start position:0% +to hire me + + + align:start position:0% +to hire me +okay yet MIT has monopsony power over me + + align:start position:0% +okay yet MIT has monopsony power over me + + + align:start position:0% +okay yet MIT has monopsony power over me +why what gives MIT monopsony power over + + align:start position:0% + + + + align:start position:0% + +me it's nothing nefarious think about + + align:start position:0% +me it's nothing nefarious think about + + + align:start position:0% +me it's nothing nefarious think about +typically any but any firm has Monopoly + + align:start position:0% +typically any but any firm has Monopoly + + + align:start position:0% +typically any but any firm has Monopoly +power over their employees + + align:start position:0% + + + + align:start position:0% + +why well + + align:start position:0% +why well + + + align:start position:0% +why well +yeah I don't know how much I get paid + + align:start position:0% +yeah I don't know how much I get paid + + + align:start position:0% +yeah I don't know how much I get paid +anywhere else that's one reason so + + align:start position:0% +anywhere else that's one reason so + + + align:start position:0% +anywhere else that's one reason so +there's an information + + align:start position:0% +there's an information + + + align:start position:0% +there's an information +reason what else now let's actually + + align:start position:0% +reason what else now let's actually + + + align:start position:0% +reason what else now let's actually +let's compare that actually I know how + + align:start position:0% +let's compare that actually I know how + + + align:start position:0% +let's compare that actually I know how +to get paid in California because + + align:start position:0% +to get paid in California because + + + align:start position:0% +to get paid in California because +California public schools have to make + + align:start position:0% +California public schools have to make + + + align:start position:0% +California public schools have to make +their wages public so let's say I could + + align:start position:0% +their wages public so let's say I could + + + align:start position:0% +their wages public so let's say I could +overcome that actually if you go online + + align:start position:0% +overcome that actually if you go online + + + align:start position:0% +overcome that actually if you go online +you want know when it's paid at a public + + align:start position:0% +you want know when it's paid at a public + + + align:start position:0% +you want know when it's paid at a public +university in America you can figure + + align:start position:0% +university in America you can figure + + + align:start position:0% +university in America you can figure +that out okay so let's say I could solve + + align:start position:0% +that out okay so let's say I could solve + + + align:start position:0% +that out okay so let's say I could solve +that problem but there's other reasons + + align:start position:0% +that problem but there's other reasons + + + align:start position:0% +that problem but there's other reasons +why MIT is monop power let's say if they + + align:start position:0% +why MIT is monop power let's say if they + + + align:start position:0% +why MIT is monop power let's say if they +mov to California + + align:start position:0% + + + + align:start position:0% + +yeah well I'm established I I have to + + align:start position:0% +yeah well I'm established I I have to + + + align:start position:0% +yeah well I'm established I I have to + move right like if I want to go + + align:start position:0% + move right like if I want to go + + + align:start position:0% + move right like if I want to go +to California I gotta move that sucks I + + align:start position:0% +to California I gotta move that sucks I + + + align:start position:0% +to California I gotta move that sucks I +gotta pack up the house I got to leave + + align:start position:0% +gotta pack up the house I got to leave + + + align:start position:0% +gotta pack up the house I got to leave +all my friends uh in particular my wife + + align:start position:0% +all my friends uh in particular my wife + + + align:start position:0% +all my friends uh in particular my wife +might have a job that she likes here my + + align:start position:0% +might have a job that she likes here my + + + align:start position:0% +might have a job that she likes here my +kids might like being in school here so + + align:start position:0% +kids might like being in school here so + + + align:start position:0% +kids might like being in school here so +there's a huge transaction cost + + align:start position:0% +there's a huge transaction cost + + + align:start position:0% +there's a huge transaction cost +transaction costs create monopsony power + + align:start position:0% +transaction costs create monopsony power + + + align:start position:0% +transaction costs create monopsony power +it's not a mining town me it's not a + + align:start position:0% +it's not a mining town me it's not a + + + align:start position:0% +it's not a mining town me it's not a +mining town but it still has Market + + align:start position:0% +mining town but it still has Market + + + align:start position:0% +mining town but it still has Market +power over me because of transaction + + align:start position:0% +power over me because of transaction + + + align:start position:0% +power over me because of transaction +costs do also the fact I like teaching + + align:start position:0% +costs do also the fact I like teaching + + + align:start position:0% +costs do also the fact I like teaching +MIT I've got my lecture set the to some + + align:start position:0% +MIT I've got my lecture set the to some + + + align:start position:0% +MIT I've got my lecture set the to some +other univers I have to dumb them down + + align:start position:0% +other univers I have to dumb them down + + + align:start position:0% +other univers I have to dumb them down +because the students aren't as smart as + + align:start position:0% +because the students aren't as smart as + + + align:start position:0% +because the students aren't as smart as +MIT I don't want to do that I've got I + + align:start position:0% +MIT I don't want to do that I've got I + + + align:start position:0% +MIT I don't want to do that I've got I +my office has a window view it's pretty + + align:start position:0% +my office has a window view it's pretty + + + align:start position:0% +my office has a window view it's pretty +awesome my window has an has a river + + align:start position:0% +awesome my window has an has a river + + + align:start position:0% +awesome my window has an has a river +view my office has a window view Jesus + + align:start position:0% +view my office has a window view Jesus + + + align:start position:0% +view my office has a window view Jesus +my my office has a Riverview through the + + align:start position:0% +my my office has a Riverview through the + + + align:start position:0% +my my office has a Riverview through the +window okay that's pretty awesome that' + + align:start position:0% +window okay that's pretty awesome that' + + + align:start position:0% +window okay that's pretty awesome that' +be hard to replicate a lot of other + + align:start position:0% +be hard to replicate a lot of other + + + align:start position:0% +be hard to replicate a lot of other +universities + + align:start position:0% +universities + + + align:start position:0% +universities +basically every job change in jobs comes + + align:start position:0% +basically every job change in jobs comes + + + align:start position:0% +basically every job change in jobs comes +with transaction costs transaction costs + + align:start position:0% +with transaction costs transaction costs + + + align:start position:0% +with transaction costs transaction costs +create monopsony power MIT does not have + + align:start position:0% +create monopsony power MIT does not have + + + align:start position:0% +create monopsony power MIT does not have +to pay me the market + + align:start position:0% +to pay me the market + + + align:start position:0% +to pay me the market +wage because of these transaction costs + + align:start position:0% +wage because of these transaction costs + + + align:start position:0% +wage because of these transaction costs +and because of information + + align:start position:0% +and because of information + + + align:start position:0% +and because of information +limitations okay so it's not crazy to + + align:start position:0% +limitations okay so it's not crazy to + + + align:start position:0% +limitations okay so it's not crazy to +think indeed we now think that basically + + align:start position:0% +think indeed we now think that basically + + + align:start position:0% +think indeed we now think that basically +monopsony is a better description of + + align:start position:0% +monopsony is a better description of + + + align:start position:0% +monopsony is a better description of +almost all labor markets than is perfect + + align:start position:0% +almost all labor markets than is perfect + + + align:start position:0% +almost all labor markets than is perfect +competition this is a real SE change in + + align:start position:0% +competition this is a real SE change in + + + align:start position:0% +competition this is a real SE change in +the last 20 years is a real sort of + + align:start position:0% +the last 20 years is a real sort of + + + align:start position:0% +the last 20 years is a real sort of +takeover the monop city model in labor + + align:start position:0% +takeover the monop city model in labor + + + align:start position:0% +takeover the monop city model in labor +economics that we think it's probably + + align:start position:0% +economics that we think it's probably + + + align:start position:0% +economics that we think it's probably +much more likely if firms have monopsony + + align:start position:0% +much more likely if firms have monopsony + + + align:start position:0% +much more likely if firms have monopsony +power than that they're perfectly + + align:start position:0% +power than that they're perfectly + + + align:start position:0% +power than that they're perfectly +competitive okay + + align:start position:0% + + + + align:start position:0% + +yeah in the new higher market so that's + + align:start position:0% +yeah in the new higher market so that's + + + align:start position:0% +yeah in the new higher market so that's +a great Point there's still the + + align:start position:0% +a great Point there's still the + + + align:start position:0% +a great Point there's still the +information issue which is I'd have to + + align:start position:0% +information issue which is I'd have to + + + align:start position:0% +information issue which is I'd have to +go and collect a bunch of offers but + + align:start position:0% +go and collect a bunch of offers but + + + align:start position:0% +go and collect a bunch of offers but +other than that you're right you would + + align:start position:0% +other than that you're right you would + + + align:start position:0% +other than that you're right you would +think and indeed if you look at salaries + + align:start position:0% +think and indeed if you look at salaries + + + align:start position:0% +think and indeed if you look at salaries +of + + align:start position:0% +of + + + align:start position:0% +of +academics new higher salaries if you + + align:start position:0% +academics new higher salaries if you + + + align:start position:0% +academics new higher salaries if you +look at Sal academics you can basically + + align:start position:0% +look at Sal academics you can basically + + + align:start position:0% +look at Sal academics you can basically +predict them pretty well based on two + + align:start position:0% +predict them pretty well based on two + + + align:start position:0% +predict them pretty well based on two +based on essentially when do they get + + align:start position:0% +based on essentially when do they get + + + align:start position:0% +based on essentially when do they get +their last offer so new higher salaries + + align:start position:0% +their last offer so new higher salaries + + + align:start position:0% +their last offer so new higher salaries +are pretty flat and you'll get raises + + align:start position:0% +are pretty flat and you'll get raises + + + align:start position:0% +are pretty flat and you'll get raises +when they get an offer from another + + align:start position:0% +when they get an offer from another + + + align:start position:0% +when they get an offer from another +University so basically MIT will + + align:start position:0% +University so basically MIT will + + + align:start position:0% +University so basically MIT will +underpay you until you get an offer from + + align:start position:0% +underpay you until you get an offer from + + + align:start position:0% +underpay you until you get an offer from +another University and then they'll then + + align:start position:0% +another University and then they'll then + + + align:start position:0% +another University and then they'll then +they'll because that reveals information + + align:start position:0% +they'll because that reveals information + + + align:start position:0% +they'll because that reveals information +and then MIT can then can then do that + + align:start position:0% +and then MIT can then can then do that + + + align:start position:0% +and then MIT can then can then do that +okay good question all right now what + + align:start position:0% +okay good question all right now what + + + align:start position:0% +okay good question all right now what +does this mean for the government well + + align:start position:0% +does this mean for the government well + + + align:start position:0% +does this mean for the government well +this means that there is scope for gains + + align:start position:0% +this means that there is scope for gains + + + align:start position:0% +this means that there is scope for gains +from regulation because look this + + align:start position:0% +from regulation because look this + + + align:start position:0% +from regulation because look this +monopis has created a dead weight loss + + align:start position:0% +monopis has created a dead weight loss + + + align:start position:0% +monopis has created a dead weight loss +look at the we we off have 30 workers so + + align:start position:0% +look at the we we off have 30 workers so + + + align:start position:0% +look at the we we off have 30 workers so +a deadweight loss triangle from only + + align:start position:0% +a deadweight loss triangle from only + + + align:start position:0% +a deadweight loss triangle from only +hiring 20 workers that says their scope + + align:start position:0% +hiring 20 workers that says their scope + + + align:start position:0% +hiring 20 workers that says their scope +for optimal regulation just like the + + align:start position:0% +for optimal regulation just like the + + + align:start position:0% +for optimal regulation just like the +scope to Optimal regulation of monop of + + align:start position:0% +scope to Optimal regulation of monop of + + + align:start position:0% +scope to Optimal regulation of monop of +monopolis and what would optimal + + align:start position:0% +monopolis and what would optimal + + + align:start position:0% +monopolis and what would optimal +regulation look like well it could look + + align:start position:0% +regulation look like well it could look + + + align:start position:0% +regulation look like well it could look +like a minimum wage so imagine if figure + + align:start position:0% +like a minimum wage so imagine if figure + + + align:start position:0% +like a minimum wage so imagine if figure +165 we set a minimum wage equal to the + + align:start position:0% +165 we set a minimum wage equal to the + + + align:start position:0% +165 we set a minimum wage equal to the +market + + align:start position:0% +market + + + align:start position:0% +market +wage well now think about the firm's + + align:start position:0% +wage well now think about the firm's + + + align:start position:0% +wage well now think about the firm's +decision for any workers to the left of + + align:start position:0% +decision for any workers to the left of + + + align:start position:0% +decision for any workers to the left of +LM there's no poisoning effect because + + align:start position:0% +LM there's no poisoning effect because + + + align:start position:0% +LM there's no poisoning effect because +they can't lower the wage so they might + + align:start position:0% +they can't lower the wage so they might + + + align:start position:0% +they can't lower the wage so they might +as well higher the competitive level + + align:start position:0% +as well higher the competitive level + + + align:start position:0% +as well higher the competitive level +what has the minimum wage just done it + + align:start position:0% +what has the minimum wage just done it + + + align:start position:0% +what has the minimum wage just done it +has raised + + align:start position:0% +has raised + + + align:start position:0% +has raised +employment so this is how you can get + + align:start position:0% +employment so this is how you can get + + + align:start position:0% +employment so this is how you can get +this weird result that a minimum wage + + align:start position:0% +this weird result that a minimum wage + + + align:start position:0% +this weird result that a minimum wage +can raise employment because what the + + align:start position:0% +can raise employment because what the + + + align:start position:0% +can raise employment because what the +minimum wage has done has essentially + + align:start position:0% +minimum wage has done has essentially + + + align:start position:0% +minimum wage has done has essentially +eroded monopsony power or eroded the + + align:start position:0% +eroded monopsony power or eroded the + + + align:start position:0% +eroded monopsony power or eroded the +negative effects of monopsony by getting + + align:start position:0% +negative effects of monopsony by getting + + + align:start position:0% +negative effects of monopsony by getting +rid of this poisoning effect by saying + + align:start position:0% +rid of this poisoning effect by saying + + + align:start position:0% +rid of this poisoning effect by saying +well firms might as well hire Elm the + + align:start position:0% +well firms might as well hire Elm the + + + align:start position:0% +well firms might as well hire Elm the +reason they were hiring lower than El + + align:start position:0% +reason they were hiring lower than El + + + align:start position:0% +reason they were hiring lower than El +comp before was because they could lower + + align:start position:0% +comp before was because they could lower + + + align:start position:0% +comp before was because they could lower +the wage but now they + + align:start position:0% +the wage but now they + + + align:start position:0% +the wage but now they +can't so that is how a minimum wage can + + align:start position:0% +can't so that is how a minimum wage can + + + align:start position:0% +can't so that is how a minimum wage can +raise employment now of course so in + + align:start position:0% +raise employment now of course so in + + + align:start position:0% +raise employment now of course so in +subsets you can get a win-win government + + align:start position:0% +subsets you can get a win-win government + + + align:start position:0% +subsets you can get a win-win government +policy you can transfer Surplus to + + align:start position:0% +policy you can transfer Surplus to + + + align:start position:0% +policy you can transfer Surplus to +Consumers and raise employment everybody + + align:start position:0% +Consumers and raise employment everybody + + + align:start position:0% +Consumers and raise employment everybody +wins and that's how government policy + + align:start position:0% +wins and that's how government policy + + + align:start position:0% +wins and that's how government policy +can make things better in imperfect Mark + + align:start position:0% +can make things better in imperfect Mark + + + align:start position:0% +can make things better in imperfect Mark +with market + + align:start position:0% +with market + + + align:start position:0% +with market +failures now of course that isn't + + align:start position:0% +failures now of course that isn't + + + align:start position:0% +failures now of course that isn't +necessarily + + align:start position:0% +necessarily + + + align:start position:0% +necessarily +true what would happen if you set the + + align:start position:0% +true what would happen if you set the + + + align:start position:0% +true what would happen if you set the +minimum wage well let me ask first what + + align:start position:0% +minimum wage well let me ask first what + + + align:start position:0% +minimum wage well let me ask first what +happen if you set the minimum wage too + + align:start position:0% +happen if you set the minimum wage too + + + align:start position:0% +happen if you set the minimum wage too +low what if you set the minimum wage + + align:start position:0% +low what if you set the minimum wage + + + align:start position:0% +low what if you set the minimum wage +below + + align:start position:0% +below + + + align:start position:0% +below +W1 what would happen if the government + + align:start position:0% +W1 what would happen if the government + + + align:start position:0% +W1 what would happen if the government +put a minimum wage in was below + + align:start position:0% +put a minimum wage in was below + + + align:start position:0% +put a minimum wage in was below +W1 yeah no effect very important the + + align:start position:0% +W1 yeah no effect very important the + + + align:start position:0% +W1 yeah no effect very important the +private Market will always get around + + align:start position:0% +private Market will always get around + + + align:start position:0% +private Market will always get around +government regulations if it can a + + align:start position:0% +government regulations if it can a + + + align:start position:0% +government regulations if it can a +government regulation that doesn't bind + + align:start position:0% +government regulation that doesn't bind + + + align:start position:0% +government regulation that doesn't bind +is no government regulation at all it + + align:start position:0% +is no government regulation at all it + + + align:start position:0% +is no government regulation at all it +sounds obvious but it's not it's + + align:start position:0% +sounds obvious but it's not it's + + + align:start position:0% +sounds obvious but it's not it's +important to remember the first thing + + align:start position:0% +important to remember the first thing + + + align:start position:0% +important to remember the first thing +after to go regulations is do they + + align:start position:0% +after to go regulations is do they + + + align:start position:0% +after to go regulations is do they +matter okay then basically as you think + + align:start position:0% +matter okay then basically as you think + + + align:start position:0% +matter okay then basically as you think +about any minimum wage between + + align:start position:0% +about any minimum wage between + + + align:start position:0% +about any minimum wage between +W1 and even past W comp they will + + align:start position:0% +W1 and even past W comp they will + + + align:start position:0% +W1 and even past W comp they will +actually improve welfare but as it gets + + align:start position:0% +actually improve welfare but as it gets + + + align:start position:0% +actually improve welfare but as it gets +high enough the minimum wage could + + align:start position:0% +high enough the minimum wage could + + + align:start position:0% +high enough the minimum wage could +actually and cause firms once the + + align:start position:0% +actually and cause firms once the + + + align:start position:0% +actually and cause firms once the +minimum wage gets above + + align:start position:0% +minimum wage gets above + + + align:start position:0% +minimum wage gets above +um the level on the marginal revenue + + align:start position:0% +um the level on the marginal revenue + + + align:start position:0% +um the level on the marginal revenue +product curve that corresponds to L1 so + + align:start position:0% +product curve that corresponds to L1 so + + + align:start position:0% +product curve that corresponds to L1 so +you see where the L1 dash line hits the + + align:start position:0% +you see where the L1 dash line hits the + + + align:start position:0% +you see where the L1 dash line hits the +marginal revenue product curve once the + + align:start position:0% +marginal revenue product curve once the + + + align:start position:0% +marginal revenue product curve once the +wage gets above that level then you're + + align:start position:0% +wage gets above that level then you're + + + align:start position:0% +wage gets above that level then you're +making things worse you end up hiring + + align:start position:0% +making things worse you end up hiring + + + align:start position:0% +making things worse you end up hiring +fewer workers then the monopus would + + align:start position:0% +fewer workers then the monopus would + + + align:start position:0% +fewer workers then the monopus would +hire so once again the way to think + + align:start position:0% +hire so once again the way to think + + + align:start position:0% +hire so once again the way to think +government regulation once again come + + align:start position:0% +government regulation once again come + + + align:start position:0% +government regulation once again come +take 1441 we'll spend all semester on + + align:start position:0% +take 1441 we'll spend all semester on + + + align:start position:0% +take 1441 we'll spend all semester on +this the way to think about it is the + + align:start position:0% +this the way to think about it is the + + + align:start position:0% +this the way to think about it is the +market knows best unless there's a + + align:start position:0% +market knows best unless there's a + + + align:start position:0% +market knows best unless there's a +market failure the market failure raises + + align:start position:0% +market failure the market failure raises + + + align:start position:0% +market failure the market failure raises +the PO potential for the government to + + align:start position:0% +the PO potential for the government to + + + align:start position:0% +the PO potential for the government to +improve things but doesn't prove + + align:start position:0% +improve things but doesn't prove + + + align:start position:0% +improve things but doesn't prove +government will Pro improve things it + + align:start position:0% +government will Pro improve things it + + + align:start position:0% +government will Pro improve things it +does not prove government will improve + + align:start position:0% +does not prove government will improve + + + align:start position:0% +does not prove government will improve +things you need to actually study and + + align:start position:0% +things you need to actually study and + + + align:start position:0% +things you need to actually study and +examine the government policy to see if + + align:start position:0% +examine the government policy to see if + + + align:start position:0% +examine the government policy to see if +it makes it better or worse for minimum + + align:start position:0% +it makes it better or worse for minimum + + + align:start position:0% +it makes it better or worse for minimum +wages basically the consensus now is for + + align:start position:0% +wages basically the consensus now is for + + + align:start position:0% +wages basically the consensus now is for +minimum wages in the range that minimum + + align:start position:0% +minimum wages in the range that minimum + + + align:start position:0% +minimum wages in the range that minimum +wages are set in America which is being + + align:start position:0% +wages are set in America which is being + + + align:start position:0% +wages are set in America which is being +probably about $8 and12 an hour okay + + align:start position:0% +probably about $8 and12 an hour okay + + + align:start position:0% +probably about $8 and12 an hour okay +where most minimum wages are we the + + align:start position:0% +where most minimum wages are we the + + + align:start position:0% +where most minimum wages are we the +consensus seems to be that they are a + + align:start position:0% +consensus seems to be that they are a + + + align:start position:0% +consensus seems to be that they are a +good thing that basically they can cause + + align:start position:0% +good thing that basically they can cause + + + align:start position:0% +good thing that basically they can cause +benefits to workers without actually + + align:start position:0% +benefits to workers without actually + + + align:start position:0% +benefits to workers without actually +reducing employment once you get above + + align:start position:0% +reducing employment once you get above + + + align:start position:0% +reducing employment once you get above +12 the evidence gets more mixed so we + + align:start position:0% +12 the evidence gets more mixed so we + + + align:start position:0% +12 the evidence gets more mixed so we +now are seeing a series of 15-hour wage + + align:start position:0% +now are seeing a series of 15-hour wage + + + align:start position:0% +now are seeing a series of 15-hour wage +dollar minimum wage including + + align:start position:0% +dollar minimum wage including + + + align:start position:0% +dollar minimum wage including +Massachusetts the evidence on those is a + + align:start position:0% +Massachusetts the evidence on those is a + + + align:start position:0% +Massachusetts the evidence on those is a +little more mixed we need a little more + + align:start position:0% +little more mixed we need a little more + + + align:start position:0% +little more mixed we need a little more +time to study but there's some level at + + align:start position:0% +time to study but there's some level at + + + align:start position:0% +time to study but there's some level at +which a minimum wage definitionally is + + align:start position:0% +which a minimum wage definitionally is + + + align:start position:0% +which a minimum wage definitionally is +high enough it will cause unemployment + + align:start position:0% +high enough it will cause unemployment + + + align:start position:0% +high enough it will cause unemployment +that doesn't mean minum wage is bad it + + align:start position:0% +that doesn't mean minum wage is bad it + + + align:start position:0% +that doesn't mean minum wage is bad it +just means at that point there's a + + align:start position:0% +just means at that point there's a + + + align:start position:0% +just means at that point there's a +trade-off so if you go back to figure 16 + + align:start position:0% +trade-off so if you go back to figure 16 + + + align:start position:0% +trade-off so if you go back to figure 16 +um + + align:start position:0% +um + + + align:start position:0% +um +two 162 does not imply we should not + + align:start position:0% +two 162 does not imply we should not + + + align:start position:0% +two 162 does not imply we should not +have minimum + + align:start position:0% +have minimum + + + align:start position:0% +have minimum +wage 162 just says there is a tradeoff + + align:start position:0% +wage 162 just says there is a tradeoff + + + align:start position:0% +wage 162 just says there is a tradeoff +you lose efficiency but you redistribute + + align:start position:0% +you lose efficiency but you redistribute + + + align:start position:0% +you lose efficiency but you redistribute +to + + align:start position:0% +to + + + align:start position:0% +to +workers okay in a standard model that's + + align:start position:0% +workers okay in a standard model that's + + + align:start position:0% +workers okay in a standard model that's +bad because we rate consumer and + + align:start position:0% +bad because we rate consumer and + + + align:start position:0% +bad because we rate consumer and +producer Surplus the same but in the + + align:start position:0% +producer Surplus the same but in the + + + align:start position:0% +producer Surplus the same but in the +real world it might not be we might + + align:start position:0% +real world it might not be we might + + + align:start position:0% +real world it might not be we might +value consumer surplus more than + + align:start position:0% +value consumer surplus more than + + + align:start position:0% +value consumer surplus more than +producer + + align:start position:0% +producer + + + align:start position:0% +producer +Surplus so the bottom line is the + + align:start position:0% +Surplus so the bottom line is the + + + align:start position:0% +Surplus so the bottom line is the +minimum wage isn't in no situation is it + + align:start position:0% +minimum wage isn't in no situation is it + + + align:start position:0% +minimum wage isn't in no situation is it +unambiguously bad it may actually be + + align:start position:0% +unambiguously bad it may actually be + + + align:start position:0% +unambiguously bad it may actually be +unambiguously good and depends on the + + align:start position:0% +unambiguously good and depends on the + + + align:start position:0% +unambiguously good and depends on the +structure of the labor + + align:start position:0% +structure of the labor + + + align:start position:0% +structure of the labor +market okay questions about + + align:start position:0% +market okay questions about + + + align:start position:0% +market okay questions about +that so once again the idea would be MIT + + align:start position:0% +that so once again the idea would be MIT + + + align:start position:0% +that so once again the idea would be MIT +is making excess money off me because I + + align:start position:0% +is making excess money off me because I + + + align:start position:0% +is making excess money off me because I +don't want to move if the government + + align:start position:0% +don't want to move if the government + + + align:start position:0% +don't want to move if the government +came in and raised my wages not too much + + align:start position:0% +came in and raised my wages not too much + + + align:start position:0% +came in and raised my wages not too much +that would make me better off and it + + align:start position:0% +that would make me better off and it + + + align:start position:0% +that would make me better off and it +would just come out of mit's profits it + + align:start position:0% +would just come out of mit's profits it + + + align:start position:0% +would just come out of mit's profits it +would just be a + + align:start position:0% +would just be a + + + align:start position:0% +would just be a +transfer but I'd be better off and they + + align:start position:0% +transfer but I'd be better off and they + + + align:start position:0% +transfer but I'd be better off and they +would they'd maybe because they pay + + align:start position:0% +would they'd maybe because they pay + + + align:start position:0% +would they'd maybe because they pay +higher wage they may hire another + + align:start position:0% +higher wage they may hire another + + + align:start position:0% +higher wage they may hire another +another professor okay and that would + + align:start position:0% +another professor okay and that would + + + align:start position:0% +another professor okay and that would +improve efficiency all right so with + + align:start position:0% +improve efficiency all right so with + + + align:start position:0% +improve efficiency all right so with +with monopsonist minimum wage is just + + align:start position:0% +with monopsonist minimum wage is just + + + align:start position:0% +with monopsonist minimum wage is just +induce efficient + + align:start position:0% +induce efficient + + + align:start position:0% +induce efficient +transfers now that's all I want to say + + align:start position:0% +transfers now that's all I want to say + + + align:start position:0% +transfers now that's all I want to say +about Labor markets I want to turn now + + align:start position:0% +about Labor markets I want to turn now + + + align:start position:0% +about Labor markets I want to turn now +to Capital markets which are a degree + + align:start position:0% +to Capital markets which are a degree + + + align:start position:0% +to Capital markets which are a degree +more complicated and therefore a degree + + align:start position:0% +more complicated and therefore a degree + + + align:start position:0% +more complicated and therefore a degree +more + + align:start position:0% + + + + align:start position:0% + +interesting the main reason they're + + align:start position:0% +interesting the main reason they're + + + align:start position:0% +interesting the main reason they're +complicated is that + + align:start position:0% +complicated is that + + + align:start position:0% +complicated is that +capital is not tangible the way labor is + + align:start position:0% +capital is not tangible the way labor is + + + align:start position:0% +capital is not tangible the way labor is +labor you feel it you've done it it's an + + align:start position:0% +labor you feel it you've done it it's an + + + align:start position:0% +labor you feel it you've done it it's an +hour of work you know what work is + + align:start position:0% +hour of work you know what work is + + + align:start position:0% +hour of work you know what work is +capital what is it it's machines it's + + align:start position:0% +capital what is it it's machines it's + + + align:start position:0% +capital what is it it's machines it's +buildings it's vague + + align:start position:0% +buildings it's vague + + + align:start position:0% +buildings it's vague +thing so we're going to Now define + + align:start position:0% +thing so we're going to Now define + + + align:start position:0% +thing so we're going to Now define +capital more + + align:start position:0% +capital more + + + align:start position:0% +capital more +specifically by think about where + + align:start position:0% +specifically by think about where + + + align:start position:0% +specifically by think about where +Capital comes + + align:start position:0% +Capital comes + + + align:start position:0% +Capital comes +from where does the money come from to + + align:start position:0% +from where does the money come from to + + + align:start position:0% +from where does the money come from to +buy machines to finally to invest what + + align:start position:0% +buy machines to finally to invest what + + + align:start position:0% +buy machines to finally to invest what +goes all the way back to our farming + + align:start position:0% +goes all the way back to our farming + + + align:start position:0% +goes all the way back to our farming +agricultural + + align:start position:0% +agricultural + + + align:start position:0% +agricultural +economy farmers every year face a + + align:start position:0% +economy farmers every year face a + + + align:start position:0% +economy farmers every year face a +decision are they going to + + align:start position:0% +decision are they going to + + + align:start position:0% +decision are they going to +consume all of their crop or are they + + align:start position:0% +consume all of their crop or are they + + + align:start position:0% +consume all of their crop or are they +going to save some of the some of it to + + align:start position:0% +going to save some of the some of it to + + + align:start position:0% +going to save some of the some of it to +plant to create next year's + + align:start position:0% +plant to create next year's + + + align:start position:0% +plant to create next year's +crop so farmers face a decision of + + align:start position:0% +crop so farmers face a decision of + + + align:start position:0% +crop so farmers face a decision of +diverting today's consumption to + + align:start position:0% +diverting today's consumption to + + + align:start position:0% +diverting today's consumption to +tomorrow's consumption or next year's + + align:start position:0% +tomorrow's consumption or next year's + + + align:start position:0% +tomorrow's consumption or next year's +consumption how much of today's + + align:start position:0% +consumption how much of today's + + + align:start position:0% +consumption how much of today's +consumption they want to give up how + + align:start position:0% +consumption they want to give up how + + + align:start position:0% +consumption they want to give up how +much less they want to eat this year to + + align:start position:0% +much less they want to eat this year to + + + align:start position:0% +much less they want to eat this year to +have more to eat next year and that + + align:start position:0% +have more to eat next year and that + + + align:start position:0% +have more to eat next year and that +determines how many seeds they want to + + align:start position:0% +determines how many seeds they want to + + + align:start position:0% +determines how many seeds they want to +set + + align:start position:0% +set + + + align:start position:0% +set +aside that's what capital + + align:start position:0% +aside that's what capital + + + align:start position:0% +aside that's what capital +is capital is + + align:start position:0% +is capital is + + + align:start position:0% +is capital is +essentially what you take from + + align:start position:0% +essentially what you take from + + + align:start position:0% +essentially what you take from +today to have in the future when you buy + + align:start position:0% +today to have in the future when you buy + + + align:start position:0% +today to have in the future when you buy +a machine you are spending money today + + align:start position:0% +a machine you are spending money today + + + align:start position:0% +a machine you are spending money today +to get the machine so over the next few + + align:start position:0% +to get the machine so over the next few + + + align:start position:0% +to get the machine so over the next few +years it produces stuff that's no + + align:start position:0% +years it produces stuff that's no + + + align:start position:0% +years it produces stuff that's no +different than saving your + + align:start position:0% +different than saving your + + + align:start position:0% +different than saving your +seeds Okay that's what capital is is + + align:start position:0% +seeds Okay that's what capital is is + + + align:start position:0% +seeds Okay that's what capital is is +essentially the diversion of current + + align:start position:0% +essentially the diversion of current + + + align:start position:0% +essentially the diversion of current +consumption towards future + + align:start position:0% +consumption towards future + + + align:start position:0% +consumption towards future +consumption now unlike the + + align:start position:0% +consumption now unlike the + + + align:start position:0% +consumption now unlike the +farmer firms today don't get the money + + align:start position:0% +farmer firms today don't get the money + + + align:start position:0% +farmer firms today don't get the money +necessarily from themselves like the + + align:start position:0% +necessarily from themselves like the + + + align:start position:0% +necessarily from themselves like the +farmers did firms get their capital in + + align:start position:0% +farmers did firms get their capital in + + + align:start position:0% +farmers did firms get their capital in +what's called a capital Market well I + + align:start position:0% +what's called a capital Market well I + + + align:start position:0% +what's called a capital Market well I +just wrote that there firms get their + + align:start position:0% +just wrote that there firms get their + + + align:start position:0% +just wrote that there firms get their +capital in a capital Market what is the + + align:start position:0% +capital in a capital Market what is the + + + align:start position:0% +capital in a capital Market what is the +capital Market well that's a market with + + align:start position:0% +capital Market well that's a market with + + + align:start position:0% +capital Market well that's a market with +his demand for + + align:start position:0% +his demand for + + + align:start position:0% +his demand for +Capital which comes from how much which + + align:start position:0% +Capital which comes from how much which + + + align:start position:0% +Capital which comes from how much which +I'll derve in a few minutes comes from + + align:start position:0% +I'll derve in a few minutes comes from + + + align:start position:0% +I'll derve in a few minutes comes from +how much firms value the capital and a + + align:start position:0% +how much firms value the capital and a + + + align:start position:0% +how much firms value the capital and a +supply of capital well where does supply + + align:start position:0% +supply of capital well where does supply + + + align:start position:0% +supply of capital well where does supply +of capital come from what is capital + + align:start position:0% +of capital come from what is capital + + + align:start position:0% +of capital come from what is capital +it's basically the money you + + align:start position:0% +it's basically the money you + + + align:start position:0% +it's basically the money you +use to invest in the future where does + + align:start position:0% +use to invest in the future where does + + + align:start position:0% +use to invest in the future where does +it come from it comes from us the supply + + align:start position:0% +it come from it comes from us the supply + + + align:start position:0% +it come from it comes from us the supply +of capital is + + align:start position:0% +of capital is + + + align:start position:0% +of capital is +savings so the money firms use to buy + + align:start position:0% +savings so the money firms use to buy + + + align:start position:0% +savings so the money firms use to buy +their machines they borrow from + + align:start position:0% +their machines they borrow from + + + align:start position:0% +their machines they borrow from +people and that is how the Capital + + align:start position:0% +people and that is how the Capital + + + align:start position:0% +people and that is how the Capital +Market works so we talk about Capital we + + align:start position:0% +Market works so we talk about Capital we + + + align:start position:0% +Market works so we talk about Capital we +really think of it fundamentally as + + align:start position:0% +really think of it fundamentally as + + + align:start position:0% +really think of it fundamentally as +Financial Capital don't think of it + + align:start position:0% +Financial Capital don't think of it + + + align:start position:0% +Financial Capital don't think of it +anymore as machines and buildings think + + align:start position:0% +anymore as machines and buildings think + + + align:start position:0% +anymore as machines and buildings think +of it as Financial Capital the money you + + align:start position:0% +of it as Financial Capital the money you + + + align:start position:0% +of it as Financial Capital the money you +want to + + align:start position:0% +want to + + + align:start position:0% +want to +invest to divert today's consumption + + align:start position:0% +invest to divert today's consumption + + + align:start position:0% +invest to divert today's consumption +Mars consumption it comes from the + + align:start position:0% +Mars consumption it comes from the + + + align:start position:0% +Mars consumption it comes from the +savings that we do which is our decision + + align:start position:0% +savings that we do which is our decision + + + align:start position:0% +savings that we do which is our decision +to divert today's consumption to + + align:start position:0% +to divert today's consumption to + + + align:start position:0% +to divert today's consumption to +tomorrow's + + align:start position:0% +tomorrow's + + + align:start position:0% +tomorrow's +consumption okay so just + + align:start position:0% +consumption okay so just + + + align:start position:0% +consumption okay so just +as work just as workers decide how hard + + align:start position:0% +as work just as workers decide how hard + + + align:start position:0% +as work just as workers decide how hard +to work and that drives the supply of + + align:start position:0% +to work and that drives the supply of + + + align:start position:0% +to work and that drives the supply of +labor people decide how much to save and + + align:start position:0% +labor people decide how much to save and + + + align:start position:0% +labor people decide how much to save and +that drives the supply of capital so + + align:start position:0% +that drives the supply of capital so + + + align:start position:0% +that drives the supply of capital so +let's see that in figure + + align:start position:0% +let's see that in figure + + + align:start position:0% +let's see that in figure +166 figure 166 is the capital market + + align:start position:0% +166 figure 166 is the capital market + + + align:start position:0% +166 figure 166 is the capital market +equilibrium the demand for + + align:start position:0% +equilibrium the demand for + + + align:start position:0% +equilibrium the demand for +Capital comes from the marginal revenue + + align:start position:0% +Capital comes from the marginal revenue + + + align:start position:0% +Capital comes from the marginal revenue +product of + + align:start position:0% +product of + + + align:start position:0% +product of +capital just like the demand for labor + + align:start position:0% +capital just like the demand for labor + + + align:start position:0% +capital just like the demand for labor +comes the margin Revenue product of + + align:start position:0% +comes the margin Revenue product of + + + align:start position:0% +comes the margin Revenue product of +labor the demand for Capital comes the + + align:start position:0% +labor the demand for Capital comes the + + + align:start position:0% +labor the demand for Capital comes the +margin Revenue product of capital + + align:start position:0% +margin Revenue product of capital + + + align:start position:0% +margin Revenue product of capital +how much will the next unit of capital + + align:start position:0% +how much will the next unit of capital + + + align:start position:0% +how much will the next unit of capital +the next unit of financial investment + + align:start position:0% +the next unit of financial investment + + + align:start position:0% +the next unit of financial investment +what will it yield in terms of the value + + align:start position:0% +what will it yield in terms of the value + + + align:start position:0% +what will it yield in terms of the value +of what I'll + + align:start position:0% +of what I'll + + + align:start position:0% +of what I'll +produce how much will the next machine + + align:start position:0% +produce how much will the next machine + + + align:start position:0% +produce how much will the next machine +increase the quantity of goods and what + + align:start position:0% +increase the quantity of goods and what + + + align:start position:0% +increase the quantity of goods and what +can I sell those goods for so the same + + align:start position:0% +can I sell those goods for so the same + + + align:start position:0% +can I sell those goods for so the same +logic that applies to labor applies to + + align:start position:0% +logic that applies to labor applies to + + + align:start position:0% +logic that applies to labor applies to +Capital the supply of capital comes from + + align:start position:0% +Capital the supply of capital comes from + + + align:start position:0% +Capital the supply of capital comes from +workers + + align:start position:0% +workers + + + align:start position:0% +workers +saving why do workers save they save + + align:start position:0% +saving why do workers save they save + + + align:start position:0% +saving why do workers save they save +because they can get a return to that + + align:start position:0% +because they can get a return to that + + + align:start position:0% +because they can get a return to that +saving in the form of + + align:start position:0% +saving in the form of + + + align:start position:0% +saving in the form of +Interest I is the rate of interest + + align:start position:0% +Interest I is the rate of interest + + + align:start position:0% +Interest I is the rate of interest +that's the return that workers get on + + align:start position:0% +that's the return that workers get on + + + align:start position:0% +that's the return that workers get on +their savings so in other words you + + align:start position:0% +their savings so in other words you + + + align:start position:0% +their savings so in other words you +could think of I the technical defition + + align:start position:0% +could think of I the technical defition + + + align:start position:0% +could think of I the technical defition +of the interest rate is the rate that + + align:start position:0% +of the interest rate is the rate that + + + align:start position:0% +of the interest rate is the rate that +firms have to pay you to get your + + align:start position:0% +firms have to pay you to get your + + + align:start position:0% +firms have to pay you to get your +money I is the rate that firms have to + + align:start position:0% +money I is the rate that firms have to + + + align:start position:0% +money I is the rate that firms have to +pay Savers to get them to + + align:start position:0% +pay Savers to get them to + + + align:start position:0% +pay Savers to get them to +save okay so for example if the interest + + align:start position:0% +save okay so for example if the interest + + + align:start position:0% +save okay so for example if the interest +rate is 10% + + align:start position:0% +rate is 10% + + + align:start position:0% +rate is 10% +then if a house if I want to borrow a + + align:start position:0% +then if a house if I want to borrow a + + + align:start position:0% +then if a house if I want to borrow a +dollar from a household this period I + + align:start position:0% +dollar from a household this period I + + + align:start position:0% +dollar from a household this period I +have to pay them back a11 next + + align:start position:0% +have to pay them back a11 next + + + align:start position:0% +have to pay them back a11 next +period let me by the way one + + align:start position:0% +period let me by the way one + + + align:start position:0% +period let me by the way one +parenthetical comment time is a very + + align:start position:0% +parenthetical comment time is a very + + + align:start position:0% +parenthetical comment time is a very +elastic Concept in this class man don't + + align:start position:0% +elastic Concept in this class man don't + + + align:start position:0% +elastic Concept in this class man don't +be uptight in your thinking like the + + align:start position:0% +be uptight in your thinking like the + + + align:start position:0% +be uptight in your thinking like the +dude says okay basically time sometimes + + align:start position:0% +dude says okay basically time sometimes + + + align:start position:0% +dude says okay basically time sometimes +I'll say today tomorrow sometimes I'll + + align:start position:0% +I'll say today tomorrow sometimes I'll + + + align:start position:0% +I'll say today tomorrow sometimes I'll +say this year next year it's all the + + align:start position:0% +say this year next year it's all the + + + align:start position:0% +say this year next year it's all the +same man just means period one versus + + align:start position:0% +same man just means period one versus + + + align:start position:0% +same man just means period one versus +period two so don't get too caught up in + + align:start position:0% +period two so don't get too caught up in + + + align:start position:0% +period two so don't get too caught up in +the words I use just think of this as + + align:start position:0% +the words I use just think of this as + + + align:start position:0% +the words I use just think of this as +period one versus period two + + align:start position:0% +period one versus period two + + + align:start position:0% +period one versus period two +okay that's that's the key and I'll try + + align:start position:0% +okay that's that's the key and I'll try + + + align:start position:0% +okay that's that's the key and I'll try +to use as much as I can but I say today + + align:start position:0% +to use as much as I can but I say today + + + align:start position:0% +to use as much as I can but I say today +tomorrow this year next year it's all + + align:start position:0% +tomorrow this year next year it's all + + + align:start position:0% +tomorrow this year next year it's all +the same thing okay so don't do too + + align:start position:0% +the same thing okay so don't do too + + + align:start position:0% +the same thing okay so don't do too +caught up on the + + align:start position:0% +caught up on the + + + align:start position:0% +caught up on the +terminology now basically the idea is + + align:start position:0% +terminology now basically the idea is + + + align:start position:0% +terminology now basically the idea is +that the Su demand curve is downward + + align:start position:0% +that the Su demand curve is downward + + + align:start position:0% +that the Su demand curve is downward +sloping as the interest rate + + align:start position:0% +sloping as the interest rate + + + align:start position:0% +sloping as the interest rate +Rises firms want less + + align:start position:0% +Rises firms want less + + + align:start position:0% +Rises firms want less +Capital because why because interest + + align:start position:0% +Capital because why because interest + + + align:start position:0% +Capital because why because interest +rate Rising means that the opportunity + + align:start position:0% +rate Rising means that the opportunity + + + align:start position:0% +rate Rising means that the opportunity +cost employing machine has gone up + + align:start position:0% +cost employing machine has gone up + + + align:start position:0% +cost employing machine has gone up +because what can you do instead with + + align:start position:0% +because what can you do instead with + + + align:start position:0% +because what can you do instead with +your money hire a + + align:start position:0% +your money hire a + + + align:start position:0% +your money hire a +worker so an up a a downward sloping + + align:start position:0% +worker so an up a a downward sloping + + + align:start position:0% +worker so an up a a downward sloping +demand curve for capital is basically + + align:start position:0% +demand curve for capital is basically + + + align:start position:0% +demand curve for capital is basically +the rate at which firms are going to + + align:start position:0% +the rate at which firms are going to + + + align:start position:0% +the rate at which firms are going to +trade off capital for labor as interest + + align:start position:0% +trade off capital for labor as interest + + + align:start position:0% +trade off capital for labor as interest +State goes up they'll say fewer machines + + align:start position:0% +State goes up they'll say fewer machines + + + align:start position:0% +State goes up they'll say fewer machines +more labor and St goes down they'll say + + align:start position:0% +more labor and St goes down they'll say + + + align:start position:0% +more labor and St goes down they'll say +less labor more + + align:start position:0% +less labor more + + + align:start position:0% +less labor more +machines the supply curve slopes up + + align:start position:0% +machines the supply curve slopes up + + + align:start position:0% +machines the supply curve slopes up +because basically the more you pay + + align:start position:0% +because basically the more you pay + + + align:start position:0% +because basically the more you pay +people to save the more they'll + + align:start position:0% +people to save the more they'll + + + align:start position:0% +people to save the more they'll +save okay now let me pause for a second + + align:start position:0% +save okay now let me pause for a second + + + align:start position:0% +save okay now let me pause for a second +we are we have a whole series of courses + + align:start position:0% +we are we have a whole series of courses + + + align:start position:0% +we are we have a whole series of courses +in course 15 about the about Finance I'm + + align:start position:0% +in course 15 about the about Finance I'm + + + align:start position:0% +in course 15 about the about Finance I'm +doing Finance in like a lecture and a + + align:start position:0% +doing Finance in like a lecture and a + + + align:start position:0% +doing Finance in like a lecture and a +half here okay and if you find this + + align:start position:0% +half here okay and if you find this + + + align:start position:0% +half here okay and if you find this +interesting you take 1541 1542 the whole + + align:start position:0% +interesting you take 1541 1542 the whole + + + align:start position:0% +interesting you take 1541 1542 the whole +series of course you take course 15 by + + align:start position:0% +series of course you take course 15 by + + + align:start position:0% +series of course you take course 15 by +the way since all of you should really + + align:start position:0% +the way since all of you should really + + + align:start position:0% +the way since all of you should really +go be econ Majors you get economics + + align:start position:0% +go be econ Majors you get economics + + + align:start position:0% +go be econ Majors you get economics +elective credit for a couple of those + + align:start position:0% +elective credit for a couple of those + + + align:start position:0% +elective credit for a couple of those +courses you can Eon major and take some + + align:start position:0% +courses you can Eon major and take some + + + align:start position:0% +courses you can Eon major and take some +course 15 courses if you want to learn + + align:start position:0% +course 15 courses if you want to learn + + + align:start position:0% +course 15 courses if you want to learn +more more about Finance okay so + + align:start position:0% +more more about Finance okay so + + + align:start position:0% +more more about Finance okay so +basically um but let's just talk about + + align:start position:0% +basically um but let's just talk about + + + align:start position:0% +basically um but let's just talk about +this weird thing I'm talking about what + + align:start position:0% +this weird thing I'm talking about what + + + align:start position:0% +this weird thing I'm talking about what +does it mean that people loan money to a + + align:start position:0% +does it mean that people loan money to a + + + align:start position:0% +does it mean that people loan money to a +firm because we don't really necess loan + + align:start position:0% +firm because we don't really necess loan + + + align:start position:0% +firm because we don't really necess loan +money to a firm in fact firms get their + + align:start position:0% +money to a firm in fact firms get their + + + align:start position:0% +money to a firm in fact firms get their +money from people in three different + + align:start position:0% +money from people in three different + + + align:start position:0% +money from people in three different +ways there's three different ways we can + + align:start position:0% +ways there's three different ways we can + + + align:start position:0% +ways there's three different ways we can +essentially transfer our money to + + align:start position:0% +essentially transfer our money to + + + align:start position:0% +essentially transfer our money to +firms one + + align:start position:0% +firms one + + + align:start position:0% +firms one +way is we could put it in the + + align:start position:0% +way is we could put it in the + + + align:start position:0% +way is we could put it in the +bank okay you put your money in the bank + + align:start position:0% +bank okay you put your money in the bank + + + align:start position:0% +bank okay you put your money in the bank +the bank pays you an interest rate + + align:start position:0% +the bank pays you an interest rate + + + align:start position:0% +the bank pays you an interest rate +firms then go to the bank and borrow the + + align:start position:0% +firms then go to the bank and borrow the + + + align:start position:0% +firms then go to the bank and borrow the +money from the bank so we're not direct + + align:start position:0% +money from the bank so we're not direct + + + align:start position:0% +money from the bank so we're not direct +leaving the money to the firms we're + + align:start position:0% +leaving the money to the firms we're + + + align:start position:0% +leaving the money to the firms we're +doing it through an through a financial + + align:start position:0% +doing it through an through a financial + + + align:start position:0% +doing it through an through a financial +intermediary which is the bank so the + + align:start position:0% +intermediary which is the bank so the + + + align:start position:0% +intermediary which is the bank so the +most common way people get money to + + align:start position:0% +most common way people get money to + + + align:start position:0% +most common way people get money to +firms is by having money in the bank you + + align:start position:0% +firms is by having money in the bank you + + + align:start position:0% +firms is by having money in the bank you +don't know that you just think you're + + align:start position:0% +don't know that you just think you're + + + align:start position:0% +don't know that you just think you're +got a bank account yielding whatever but + + align:start position:0% +got a bank account yielding whatever but + + + align:start position:0% +got a bank account yielding whatever but +that's what you're doing you're just + + align:start position:0% +that's what you're doing you're just + + + align:start position:0% +that's what you're doing you're just +giving money to + + align:start position:0% +giving money to + + + align:start position:0% +giving money to +firms the second way you can do it is + + align:start position:0% +firms the second way you can do it is + + + align:start position:0% +firms the second way you can do it is +you can actually directly loan the money + + align:start position:0% +you can actually directly loan the money + + + align:start position:0% +you can actually directly loan the money +to the firm by buying corporate + + align:start position:0% +to the firm by buying corporate + + + align:start position:0% +to the firm by buying corporate +bonds okay a corporate bond is literally + + align:start position:0% +bonds okay a corporate bond is literally + + + align:start position:0% +bonds okay a corporate bond is literally +a loan to a firm now typically most of + + align:start position:0% +a loan to a firm now typically most of + + + align:start position:0% +a loan to a firm now typically most of +us who aren't Super Rich won't buy a + + align:start position:0% +us who aren't Super Rich won't buy a + + + align:start position:0% +us who aren't Super Rich won't buy a +corporate bond will buy a financial + + align:start position:0% +corporate bond will buy a financial + + + align:start position:0% +corporate bond will buy a financial +instrument that holds corporate bonds + + align:start position:0% +instrument that holds corporate bonds + + + align:start position:0% +instrument that holds corporate bonds +okay so I have a Vanguard bond fund + + align:start position:0% +okay so I have a Vanguard bond fund + + + align:start position:0% +okay so I have a Vanguard bond fund +Vanguard is a company that holds + + align:start position:0% +Vanguard is a company that holds + + + align:start position:0% +Vanguard is a company that holds +financial instruments so I own a little + + align:start position:0% +financial instruments so I own a little + + + align:start position:0% +financial instruments so I own a little +piece of a lot of bonds okay bonds are + + align:start position:0% +piece of a lot of bonds okay bonds are + + + align:start position:0% +piece of a lot of bonds okay bonds are +like millions of dollars I'm not gonna + + align:start position:0% +like millions of dollars I'm not gonna + + + align:start position:0% +like millions of dollars I'm not gonna +own a bond but I own a little piece of a + + align:start position:0% +own a bond but I own a little piece of a + + + align:start position:0% +own a bond but I own a little piece of a +bunch of them okay so I'm sort of that's + + align:start position:0% +bunch of them okay so I'm sort of that's + + + align:start position:0% +bunch of them okay so I'm sort of that's +the way you directly loan to a firm and + + align:start position:0% +the way you directly loan to a firm and + + + align:start position:0% +the way you directly loan to a firm and +then finally you can buy stocks which is + + align:start position:0% +then finally you can buy stocks which is + + + align:start position:0% +then finally you can buy stocks which is +another way directly probably the most + + align:start position:0% +another way directly probably the most + + + align:start position:0% +another way directly probably the most +direct way to give money to a firm you + + align:start position:0% +direct way to give money to a firm you + + + align:start position:0% +direct way to give money to a firm you +can only buy a share in a firm you can + + align:start position:0% +can only buy a share in a firm you can + + + align:start position:0% +can only buy a share in a firm you can +go out tomorrow you can buy a share in + + align:start position:0% +go out tomorrow you can buy a share in + + + align:start position:0% +go out tomorrow you can buy a share in +apple you get a piece of paper that says + + align:start position:0% +apple you get a piece of paper that says + + + align:start position:0% +apple you get a piece of paper that says +you own a share of Apple okay you've + + align:start position:0% +you own a share of Apple okay you've + + + align:start position:0% +you own a share of Apple okay you've +given Apple your money what are they + + align:start position:0% +given Apple your money what are they + + + align:start position:0% +given Apple your money what are they +giving you back they're giving you back + + align:start position:0% +giving you back they're giving you back + + + align:start position:0% +giving you back they're giving you back +two + + align:start position:0% +two + + + align:start position:0% +two +things the first is they're giving you + + align:start position:0% +things the first is they're giving you + + + align:start position:0% +things the first is they're giving you +back the promise that their price of + + align:start position:0% +back the promise that their price of + + + align:start position:0% +back the promise that their price of +that stock will go up that if you buy + + align:start position:0% +that stock will go up that if you buy + + + align:start position:0% +that stock will go up that if you buy +what Apple stock let's say Apple stock + + align:start position:0% +what Apple stock let's say Apple stock + + + align:start position:0% +what Apple stock let's say Apple stock +today selling at 100 I don't know what + + align:start position:0% +today selling at 100 I don't know what + + + align:start position:0% +today selling at 100 I don't know what +selling at okay it's probably much more + + align:start position:0% +selling at okay it's probably much more + + + align:start position:0% +selling at okay it's probably much more +than that selling at a 100 if I buy for + + align:start position:0% +than that selling at a 100 if I buy for + + + align:start position:0% +than that selling at a 100 if I buy for +100 then what that means I give Apple + + align:start position:0% +100 then what that means I give Apple + + + align:start position:0% +100 then what that means I give Apple +$100 they give me a share why do I do + + align:start position:0% +$100 they give me a share why do I do + + + align:start position:0% +$100 they give me a share why do I do +that because I think in five years Apple + + align:start position:0% +that because I think in five years Apple + + + align:start position:0% +that because I think in five years Apple +will be worth + + align:start position:0% +will be worth + + + align:start position:0% +will be worth +150 and then I could sell that share to + + align:start position:0% +150 and then I could sell that share to + + + align:start position:0% +150 and then I could sell that share to +someone else and get my + + align:start position:0% +someone else and get my + + + align:start position:0% +someone else and get my +$50 okay in addition some old style + + align:start position:0% +$50 okay in addition some old style + + + align:start position:0% +$50 okay in addition some old style +firms not the new firms old style firms + + align:start position:0% +firms not the new firms old style firms + + + align:start position:0% +firms not the new firms old style firms +also sometimes will just send regular + + align:start position:0% +also sometimes will just send regular + + + align:start position:0% +also sometimes will just send regular +checks to people on their stock called + + align:start position:0% +checks to people on their stock called + + + align:start position:0% +checks to people on their stock called +dividends that happens less and less but + + align:start position:0% +dividends that happens less and less but + + + align:start position:0% +dividends that happens less and less but +basically so I can put my money in the + + align:start position:0% +basically so I can put my money in the + + + align:start position:0% +basically so I can put my money in the +bank the bank pays me Interest the fir + + align:start position:0% +bank the bank pays me Interest the fir + + + align:start position:0% +bank the bank pays me Interest the fir +them borrow from the bank I can buy a + + align:start position:0% +them borrow from the bank I can buy a + + + align:start position:0% +them borrow from the bank I can buy a +corporate bond the bond pays me Interest + + align:start position:0% +corporate bond the bond pays me Interest + + + align:start position:0% +corporate bond the bond pays me Interest +okay it's a Rec direct loan or I can buy + + align:start position:0% +okay it's a Rec direct loan or I can buy + + + align:start position:0% +okay it's a Rec direct loan or I can buy +stock in which case I give the money to + + align:start position:0% +stock in which case I give the money to + + + align:start position:0% +stock in which case I give the money to +the firm and they pay me back by getting + + align:start position:0% +the firm and they pay me back by getting + + + align:start position:0% +the firm and they pay me back by getting +more valuable or paying me a dividend + + align:start position:0% +more valuable or paying me a dividend + + + align:start position:0% +more valuable or paying me a dividend +and that's essentially how I transfer + + align:start position:0% +and that's essentially how I transfer + + + align:start position:0% +and that's essentially how I transfer +money to firms okay questions about + + align:start position:0% +money to firms okay questions about + + + align:start position:0% +money to firms okay questions about +that + + align:start position:0% +that + + + align:start position:0% +that +yeah interest + + align:start position:0% + + + + align:start position:0% + +rate you relate the interest rate to the + + align:start position:0% +rate you relate the interest rate to the + + + align:start position:0% +rate you relate the interest rate to the +slope I don't quite understand + + align:start position:0% + + + + align:start position:0% + +yeah yeah exactly there's a mathematical + + align:start position:0% +yeah yeah exactly there's a mathematical + + + align:start position:0% +yeah yeah exactly there's a mathematical +function uh essentially the demand curve + + align:start position:0% +function uh essentially the demand curve + + + align:start position:0% +function uh essentially the demand curve +will be a negative function of interest + + align:start position:0% +will be a negative function of interest + + + align:start position:0% +will be a negative function of interest +rates supply curve will be a positive + + align:start position:0% +rates supply curve will be a positive + + + align:start position:0% +rates supply curve will be a positive +function of interest rates there's a + + align:start position:0% +function of interest rates there's a + + + align:start position:0% +function of interest rates there's a +mathematical function just like other + + align:start position:0% +mathematical function just like other + + + align:start position:0% +mathematical function just like other +demand and Supply + + align:start position:0% +demand and Supply + + + align:start position:0% +demand and Supply +curves other + + align:start position:0% +curves other + + + align:start position:0% +curves other +questions okay so + + align:start position:0% +questions okay so + + + align:start position:0% +questions okay so +now let's come the demand part is sort + + align:start position:0% +now let's come the demand part is sort + + + align:start position:0% +now let's come the demand part is sort +of uninteresting we know how to drive + + align:start position:0% +of uninteresting we know how to drive + + + align:start position:0% +of uninteresting we know how to drive +this what you do is you take a + + align:start position:0% +this what you do is you take a + + + align:start position:0% +this what you do is you take a +production function you'd set up a you + + align:start position:0% +production function you'd set up a you + + + align:start position:0% +production function you'd set up a you +you would you would get a cost function + + align:start position:0% +you would you would get a cost function + + + align:start position:0% +you would you would get a cost function +you could solve for the marginal revenue + + align:start position:0% +you could solve for the marginal revenue + + + align:start position:0% +you could solve for the marginal revenue +product of capital okay you know how to + + align:start position:0% +product of capital okay you know how to + + + align:start position:0% +product of capital okay you know how to +do that the the supply side is more + + align:start position:0% +do that the the supply side is more + + + align:start position:0% +do that the the supply side is more +interesting and why is it more + + align:start position:0% +interesting and why is it more + + + align:start position:0% +interesting and why is it more +interesting because once again + + align:start position:0% +interesting because once again + + + align:start position:0% +interesting because once again +substitution income effects are going to + + align:start position:0% +substitution income effects are going to + + + align:start position:0% +substitution income effects are going to +mess things up just like they did for + + align:start position:0% +mess things up just like they did for + + + align:start position:0% +mess things up just like they did for +labor Supply they are going to do it for + + align:start position:0% +labor Supply they are going to do it for + + + align:start position:0% +labor Supply they are going to do it for +savings and they're going to do so in + + align:start position:0% +savings and they're going to do so in + + + align:start position:0% +savings and they're going to do so in +the framework of what we call + + align:start position:0% +the framework of what we call + + + align:start position:0% +the framework of what we call +intertemporal + + align:start position:0% + + + + align:start position:0% + +Choice which is your decision of how + + align:start position:0% +Choice which is your decision of how + + + align:start position:0% +Choice which is your decision of how +much do you consume and how much do you + + align:start position:0% +much do you consume and how much do you + + + align:start position:0% +much do you consume and how much do you +save so to do that let's go to figure + + align:start position:0% + + + + align:start position:0% + +16 figure + + align:start position:0% +16 figure + + + align:start position:0% +16 figure +167 and this diagram describes the + + align:start position:0% +167 and this diagram describes the + + + align:start position:0% +167 and this diagram describes the +person's decision of how much to + + align:start position:0% +person's decision of how much to + + + align:start position:0% +person's decision of how much to +save okay I'm just G this graphically in + + align:start position:0% +save okay I'm just G this graphically in + + + align:start position:0% +save okay I'm just G this graphically in +section you're going to do the + + align:start position:0% +section you're going to do the + + + align:start position:0% +section you're going to do the +math okay + + align:start position:0% +math okay + + + align:start position:0% +math okay +individuals have a utility fun function + + align:start position:0% +individuals have a utility fun function + + + align:start position:0% +individuals have a utility fun function +we talked about youtility function we + + align:start position:0% +we talked about youtility function we + + + align:start position:0% +we talked about youtility function we +choose between two goods we always do + + align:start position:0% +choose between two goods we always do + + + align:start position:0% +choose between two goods we always do +two element utility function make the + + align:start position:0% +two element utility function make the + + + align:start position:0% +two element utility function make the +math easy talk about choos two goods we + + align:start position:0% +math easy talk about choos two goods we + + + align:start position:0% +math easy talk about choos two goods we +talked about choos between consumption + + align:start position:0% +talked about choos between consumption + + + align:start position:0% +talked about choos between consumption +and Leisure now we're talking about + + align:start position:0% +and Leisure now we're talking about + + + align:start position:0% +and Leisure now we're talking about +choosing between consumption in Period + + align:start position:0% +choosing between consumption in Period + + + align:start position:0% +choosing between consumption in Period +one and consumption in Period + + align:start position:0% +one and consumption in Period + + + align:start position:0% +one and consumption in Period +two now the + + align:start position:0% +two now the + + + align:start position:0% +two now the +tradeoff instead of being + + align:start position:0% +tradeoff instead of being + + + align:start position:0% +tradeoff instead of being +between pizza and + + align:start position:0% +between pizza and + + + align:start position:0% +between pizza and +cookies or being + + align:start position:0% +cookies or being + + + align:start position:0% +cookies or being +between or being between work Leisure + + align:start position:0% +between or being between work Leisure + + + align:start position:0% +between or being between work Leisure +and and consumption now between be + + align:start position:0% +and and consumption now between be + + + align:start position:0% +and and consumption now between be +consuming today versus consuming + + align:start position:0% +consuming today versus consuming + + + align:start position:0% +consuming today versus consuming +tomorrow and we understand the trade-off + + align:start position:0% +tomorrow and we understand the trade-off + + + align:start position:0% +tomorrow and we understand the trade-off +the trade-off is that basically people + + align:start position:0% +the trade-off is that basically people + + + align:start position:0% +the trade-off is that basically people +are by and large + + align:start position:0% +are by and large + + + align:start position:0% +are by and large +impatient if you ask them would you + + align:start position:0% +impatient if you ask them would you + + + align:start position:0% +impatient if you ask them would you +rather something today or tomorrow + + align:start position:0% +rather something today or tomorrow + + + align:start position:0% +rather something today or tomorrow +they'd rather have it today okay there's + + align:start position:0% +they'd rather have it today okay there's + + + align:start position:0% +they'd rather have it today okay there's +the famous marshmallow test they do on + + align:start position:0% +the famous marshmallow test they do on + + + align:start position:0% +the famous marshmallow test they do on +little kids where they see if they'll + + align:start position:0% +little kids where they see if they'll + + + align:start position:0% +little kids where they see if they'll +wait to get a marshmallow Okay most kids + + align:start position:0% +wait to get a marshmallow Okay most kids + + + align:start position:0% +wait to get a marshmallow Okay most kids +don't humans are impatient okay we'll + + align:start position:0% +don't humans are impatient okay we'll + + + align:start position:0% +don't humans are impatient okay we'll +come back to that in a few lectures talk + + align:start position:0% +come back to that in a few lectures talk + + + align:start position:0% +come back to that in a few lectures talk +about how you model that but for now + + align:start position:0% +about how you model that but for now + + + align:start position:0% +about how you model that but for now +let's just say humans are impatient on + + align:start position:0% +let's just say humans are impatient on + + + align:start position:0% +let's just say humans are impatient on +the on the other hand humans need money + + align:start position:0% +the on the other hand humans need money + + + align:start position:0% +the on the other hand humans need money +in both periods so let's do a simple + + align:start position:0% +in both periods so let's do a simple + + + align:start position:0% +in both periods so let's do a simple +example imagine my income is $80,000 a + + align:start position:0% +example imagine my income is $80,000 a + + + align:start position:0% +example imagine my income is $80,000 a +year okay and imagine I I can save that + + align:start position:0% +year okay and imagine I I can save that + + + align:start position:0% +year okay and imagine I I can save that +money at 10% so Y is 80,000 and let's + + align:start position:0% +money at 10% so Y is 80,000 and let's + + + align:start position:0% +money at 10% so Y is 80,000 and let's +imagine I only earn the income well okay + + align:start position:0% +imagine I only earn the income well okay + + + align:start position:0% +imagine I only earn the income well okay +management income is 8,000 I can save + + align:start position:0% +management income is 8,000 I can save + + + align:start position:0% +management income is 8,000 I can save +that at 10% and next year I want to stay + + align:start position:0% +that at 10% and next year I want to stay + + + align:start position:0% +that at 10% and next year I want to stay +home take care of my + + align:start position:0% +home take care of my + + + align:start position:0% +home take care of my +kids I don't want to + + align:start position:0% +kids I don't want to + + + align:start position:0% +kids I don't want to +work so what that means my my income imp + + align:start position:0% +work so what that means my my income imp + + + align:start position:0% +work so what that means my my income imp +Peri period one will be 80,000 but my + + align:start position:0% +Peri period one will be 80,000 but my + + + align:start position:0% +Peri period one will be 80,000 but my +income in Period two will be + + align:start position:0% +income in Period two will be + + + align:start position:0% +income in Period two will be +zero guess more complicate income in + + align:start position:0% +zero guess more complicate income in + + + align:start position:0% +zero guess more complicate income in +Period two you'll see that in the + + align:start position:0% +Period two you'll see that in the + + + align:start position:0% +Period two you'll see that in the +problem set okay my Inc in Period two + + align:start position:0% +problem set okay my Inc in Period two + + + align:start position:0% +problem set okay my Inc in Period two +would be zero okay now my question is + + align:start position:0% +would be zero okay now my question is + + + align:start position:0% +would be zero okay now my question is +what do I do well you could see that in + + align:start position:0% +what do I do well you could see that in + + + align:start position:0% +what do I do well you could see that in +figure + + align:start position:0% +figure + + + align:start position:0% +figure +167 one option is figure 167 has my + + align:start position:0% +167 one option is figure 167 has my + + + align:start position:0% +167 one option is figure 167 has my +first period consumption on the xaxis my + + align:start position:0% +first period consumption on the xaxis my + + + align:start position:0% +first period consumption on the xaxis my +secondary consumption the y axis one + + align:start position:0% +secondary consumption the y axis one + + + align:start position:0% +secondary consumption the y axis one +option would be to consume everything in + + align:start position:0% +option would be to consume everything in + + + align:start position:0% +option would be to consume everything in +Year One + + align:start position:0% +Year One + + + align:start position:0% +Year One +and nothing in year two that's not very + + align:start position:0% +and nothing in year two that's not very + + + align:start position:0% +and nothing in year two that's not very +attractive the other oper consume + + align:start position:0% +attractive the other oper consume + + + align:start position:0% +attractive the other oper consume +nothing in year one in which case I + + align:start position:0% +nothing in year one in which case I + + + align:start position:0% +nothing in year one in which case I +would have 88,000 in year two why + + align:start position:0% +would have 88,000 in year two why + + + align:start position:0% +would have 88,000 in year two why +because I would save 80,000 on a 10% + + align:start position:0% +because I would save 80,000 on a 10% + + + align:start position:0% +because I would save 80,000 on a 10% +interest so what's the tradeoff the + + align:start position:0% +interest so what's the tradeoff the + + + align:start position:0% +interest so what's the tradeoff the +tradeoff is the interest + + align:start position:0% +tradeoff is the interest + + + align:start position:0% +tradeoff is the interest +rate right or in other words what is the + + align:start position:0% +rate right or in other words what is the + + + align:start position:0% +rate right or in other words what is the +price of First Period + + align:start position:0% +price of First Period + + + align:start position:0% +price of First Period +consumption the price of First Period + + align:start position:0% +consumption the price of First Period + + + align:start position:0% +consumption the price of First Period +consumption okay is minus + + align:start position:0% +consumption okay is minus + + + align:start position:0% +consumption okay is minus +okay the price for consumption is minus + + align:start position:0% +okay the price for consumption is minus + + + align:start position:0% +okay the price for consumption is minus +1 plus + + align:start position:0% +1 plus + + + align:start position:0% +1 plus +I okay the price for once again I assume + + align:start position:0% +I okay the price for once again I assume + + + align:start position:0% +I okay the price for once again I assume +all Goods have a price of one when I + + align:start position:0% +all Goods have a price of one when I + + + align:start position:0% +all Goods have a price of one when I +came to price of goods this is what is + + align:start position:0% +came to price of goods this is what is + + + align:start position:0% +came to price of goods this is what is +the relative price of First Period + + align:start position:0% +the relative price of First Period + + + align:start position:0% +the relative price of First Period +consumption okay so assume the price of + + align:start position:0% +consumption okay so assume the price of + + + align:start position:0% +consumption okay so assume the price of +consumption in Period one is one the + + align:start position:0% +consumption in Period one is one the + + + align:start position:0% +consumption in Period one is one the +price of consumption in Period two is + + align:start position:0% +price of consumption in Period two is + + + align:start position:0% +price of consumption in Period two is +one we're normalizing everything to make + + align:start position:0% +one we're normalizing everything to make + + + align:start position:0% +one we're normalizing everything to make +our math easy throwing prices out okay + + align:start position:0% +our math easy throwing prices out okay + + + align:start position:0% +our math easy throwing prices out okay +every it's just it's just we're thinking + + align:start position:0% +every it's just it's just we're thinking + + + align:start position:0% +every it's just it's just we're thinking +in terms of goods effectively here so + + align:start position:0% +in terms of goods effectively here so + + + align:start position:0% +in terms of goods effectively here so +what is the relative price of consuming + + align:start position:0% +what is the relative price of consuming + + + align:start position:0% +what is the relative price of consuming +in Period one minus 1 plus I why is that + + align:start position:0% +in Period one minus 1 plus I why is that + + + align:start position:0% +in Period one minus 1 plus I why is that +because for every dollar I consume in + + align:start position:0% +because for every dollar I consume in + + + align:start position:0% +because for every dollar I consume in +Period one I give up one plus I dollars + + align:start position:0% +Period one I give up one plus I dollars + + + align:start position:0% +Period one I give up one plus I dollars +in Period + + align:start position:0% +in Period + + + align:start position:0% +in Period +two that is the opportunity cost of + + align:start position:0% +two that is the opportunity cost of + + + align:start position:0% +two that is the opportunity cost of +first period consumption is not having + + align:start position:0% +first period consumption is not having + + + align:start position:0% +first period consumption is not having +second period consumption once again + + align:start position:0% +second period consumption once again + + + align:start position:0% +second period consumption once again +dismal + + align:start position:0% +dismal + + + align:start position:0% +dismal +science every time you eat something + + align:start position:0% +science every time you eat something + + + align:start position:0% +science every time you eat something +you're giving up the possibility of + + align:start position:0% +you're giving up the possibility of + + + align:start position:0% +you're giving up the possibility of +saving that money eating more next year + + align:start position:0% +saving that money eating more next year + + + align:start position:0% +saving that money eating more next year +okay just like there's a the price of + + align:start position:0% +okay just like there's a the price of + + + align:start position:0% +okay just like there's a the price of +leisures the wage the price of First + + align:start position:0% +leisures the wage the price of First + + + align:start position:0% +leisures the wage the price of First +Period consumption is minus one plus I + + align:start position:0% +Period consumption is minus one plus I + + + align:start position:0% +Period consumption is minus one plus I +or the interest rate the amount of money + + align:start position:0% +or the interest rate the amount of money + + + align:start position:0% +or the interest rate the amount of money +you could have the next + + align:start position:0% +you could have the next + + + align:start position:0% +you could have the next +year okay so basically that is the + + align:start position:0% +year okay so basically that is the + + + align:start position:0% +year okay so basically that is the +tradeoff that is representing the + + align:start position:0% +tradeoff that is representing the + + + align:start position:0% +tradeoff that is representing the +interal Choice problem that's + + align:start position:0% +interal Choice problem that's + + + align:start position:0% +interal Choice problem that's +represented by the slope of this budget + + align:start position:0% +represented by the slope of this budget + + + align:start position:0% +represented by the slope of this budget +constraint which is minus1 plus I or + + align:start position:0% +constraint which is minus1 plus I or + + + align:start position:0% +constraint which is minus1 plus I or +minus 1.1 in our example the slope of + + align:start position:0% +minus 1.1 in our example the slope of + + + align:start position:0% +minus 1.1 in our example the slope of +the budget create represents the + + align:start position:0% +the budget create represents the + + + align:start position:0% +the budget create represents the +opportunity cost of first period + + align:start position:0% +opportunity cost of first period + + + align:start position:0% +opportunity cost of first period +consumption in terms of second period + + align:start position:0% +consumption in terms of second period + + + align:start position:0% +consumption in terms of second period +consumption okay okay likewise I have + + align:start position:0% +consumption okay okay likewise I have + + + align:start position:0% +consumption okay okay likewise I have +some indifference curve I have some + + align:start position:0% +some indifference curve I have some + + + align:start position:0% +some indifference curve I have some +indifference curve which represents my + + align:start position:0% +indifference curve which represents my + + + align:start position:0% +indifference curve which represents my +preferences over first and second period + + align:start position:0% +preferences over first and second period + + + align:start position:0% +preferences over first and second period +consumption how impatient I am basically + + align:start position:0% +consumption how impatient I am basically + + + align:start position:0% +consumption how impatient I am basically +okay so think of the Indi curve + + align:start position:0% +okay so think of the Indi curve + + + align:start position:0% +okay so think of the Indi curve +basically being how impatient I am so + + align:start position:0% +basically being how impatient I am so + + + align:start position:0% +basically being how impatient I am so +like with all these optimization + + align:start position:0% +like with all these optimization + + + align:start position:0% +like with all these optimization +problems I know what to + + align:start position:0% +problems I know what to + + + align:start position:0% +problems I know what to +do okay I find the tangency between the + + align:start position:0% +do okay I find the tangency between the + + + align:start position:0% +do okay I find the tangency between the +indifference curve which is essentially + + align:start position:0% +indifference curve which is essentially + + + align:start position:0% +indifference curve which is essentially +my impatience period one and two and the + + align:start position:0% +my impatience period one and two and the + + + align:start position:0% +my impatience period one and two and the +budget constraint which is the market + + align:start position:0% +budget constraint which is the market + + + align:start position:0% +budget constraint which is the market +rate at which I can trade off + + align:start position:0% +rate at which I can trade off + + + align:start position:0% +rate at which I can trade off +consumption period one period two + + align:start position:0% +consumption period one period two + + + align:start position:0% +consumption period one period two +remember going all the way back to + + align:start position:0% +remember going all the way back to + + + align:start position:0% +remember going all the way back to +lecture one the idea of opportunity cost + + align:start position:0% +lecture one the idea of opportunity cost + + + align:start position:0% +lecture one the idea of opportunity cost +is kind of like the concept of + + align:start position:0% +is kind of like the concept of + + + align:start position:0% +is kind of like the concept of +alchemy where I'm not literally turning + + align:start position:0% +alchemy where I'm not literally turning + + + align:start position:0% +alchemy where I'm not literally turning +period one consumption into period two + + align:start position:0% +period one consumption into period two + + + align:start position:0% +period one consumption into period two +consumption physically but I'm + + align:start position:0% +consumption physically but I'm + + + align:start position:0% +consumption physically but I'm +effectively doing it through opportunity + + align:start position:0% +effectively doing it through opportunity + + + align:start position:0% +effectively doing it through opportunity +cost by not consuming in Period one you + + align:start position:0% +cost by not consuming in Period one you + + + align:start position:0% +cost by not consuming in Period one you +get more in Period two so it's + + align:start position:0% +get more in Period two so it's + + + align:start position:0% +get more in Period two so it's +essentially alchemy that happens through + + align:start position:0% +essentially alchemy that happens through + + + align:start position:0% +essentially alchemy that happens through +the concept of opportunity cost in this + + align:start position:0% +the concept of opportunity cost in this + + + align:start position:0% +the concept of opportunity cost in this +case it happens through saving in the + + align:start position:0% +case it happens through saving in the + + + align:start position:0% +case it happens through saving in the +bank by Saving in the bank I turn a + + align:start position:0% +bank by Saving in the bank I turn a + + + align:start position:0% +bank by Saving in the bank I turn a +dollar today into a1ar 10 tomorrow + + align:start position:0% +dollar today into a1ar 10 tomorrow + + + align:start position:0% +dollar today into a1ar 10 tomorrow +dollar period one into a dollar 10 in + + align:start position:0% +dollar period one into a dollar 10 in + + + align:start position:0% +dollar period one into a dollar 10 in +Period + + align:start position:0% +Period + + + align:start position:0% +Period +two okay and that's what's happening + + align:start position:0% +two okay and that's what's happening + + + align:start position:0% +two okay and that's what's happening +here so my optimal consumption in this + + align:start position:0% +here so my optimal consumption in this + + + align:start position:0% +here so my optimal consumption in this +case is C1 in Period one so what do I do + + align:start position:0% +case is C1 in Period one so what do I do + + + align:start position:0% +case is C1 in Period one so what do I do +I say well look given my impatience + + align:start position:0% +I say well look given my impatience + + + align:start position:0% +I say well look given my impatience +level I want to consume C1 in Period one + + align:start position:0% +level I want to consume C1 in Period one + + + align:start position:0% +level I want to consume C1 in Period one +in figure + + align:start position:0% +in figure + + + align:start position:0% +in figure +167 what that means I'm going to save + + align:start position:0% +167 what that means I'm going to save + + + align:start position:0% +167 what that means I'm going to save +80,000 minus + + align:start position:0% +80,000 minus + + + align:start position:0% +80,000 minus +C1 what does that mean my period two + + align:start position:0% +C1 what does that mean my period two + + + align:start position:0% +C1 what does that mean my period two +consumption is it means my period two + + align:start position:0% +consumption is it means my period two + + + align:start position:0% +consumption is it means my period two +consumption is going to be the amount I + + align:start position:0% +consumption is going to be the amount I + + + align:start position:0% +consumption is going to be the amount I +saved times one plus the interest + + align:start position:0% +saved times one plus the interest + + + align:start position:0% +saved times one plus the interest +rate so it's going to be 1 plus I times + + align:start position:0% +rate so it's going to be 1 plus I times + + + align:start position:0% +rate so it's going to be 1 plus I times +80,000 minus + + align:start position:0% +80,000 minus + + + align:start position:0% +80,000 minus +C + + align:start position:0% +C + + + align:start position:0% +C +C1 now once again let's remember the + + align:start position:0% +C1 now once again let's remember the + + + align:start position:0% +C1 now once again let's remember the +trick I've done here without mentioning + + align:start position:0% +trick I've done here without mentioning + + + align:start position:0% +trick I've done here without mentioning +it this lecture is supposed to be about + + align:start position:0% +it this lecture is supposed to be about + + + align:start position:0% +it this lecture is supposed to be about +savings that's the first time I've + + align:start position:0% +savings that's the first time I've + + + align:start position:0% +savings that's the first time I've +mentioned + + align:start position:0% +mentioned + + + align:start position:0% +mentioned +savings why because savings is a + + align:start position:0% +savings why because savings is a + + + align:start position:0% +savings why because savings is a +bad savings is something you just have + + align:start position:0% +bad savings is something you just have + + + align:start position:0% +bad savings is something you just have +to do to get consumption period too no + + align:start position:0% +to do to get consumption period too no + + + align:start position:0% +to do to get consumption period too no +one wants to save this one's even a + + align:start position:0% +one wants to save this one's even a + + + align:start position:0% +one wants to save this one's even a +little more realistic for you guys + + align:start position:0% +little more realistic for you guys + + + align:start position:0% +little more realistic for you guys +although you're probably probably still + + align:start position:0% +although you're probably probably still + + + align:start position:0% +although you're probably probably still +frugal people but basically the idea + + align:start position:0% +frugal people but basically the idea + + + align:start position:0% +frugal people but basically the idea +savings is not a good thing we don't + + align:start position:0% +savings is not a good thing we don't + + + align:start position:0% +savings is not a good thing we don't +have a model where people it's not a + + align:start position:0% +have a model where people it's not a + + + align:start position:0% +have a model where people it's not a +Scrooge McDuck model where people want + + align:start position:0% +Scrooge McDuck model where people want + + + align:start position:0% +Scrooge McDuck model where people want +to swim in their money okay savings is + + align:start position:0% +to swim in their money okay savings is + + + align:start position:0% +to swim in their money okay savings is +not a good thing savings is a is a + + align:start position:0% +not a good thing savings is a is a + + + align:start position:0% +not a good thing savings is a is a +necessary tool to get consumption from + + align:start position:0% +necessary tool to get consumption from + + + align:start position:0% +necessary tool to get consumption from +period one to period two it's a bad we + + align:start position:0% +period one to period two it's a bad we + + + align:start position:0% +period one to period two it's a bad we +don't model bads we model Goods so we + + align:start position:0% +don't model bads we model Goods so we + + + align:start position:0% +don't model bads we model Goods so we +don't model savings we model consumption + + align:start position:0% +don't model savings we model consumption + + + align:start position:0% +don't model savings we model consumption +and then we get savings as a residual + + align:start position:0% +and then we get savings as a residual + + + align:start position:0% +and then we get savings as a residual +so when you want to solve for savings + + align:start position:0% +so when you want to solve for savings + + + align:start position:0% +so when you want to solve for savings +you model consumption and you get + + align:start position:0% +you model consumption and you get + + + align:start position:0% +you model consumption and you get +savings as the residual just like when + + align:start position:0% +savings as the residual just like when + + + align:start position:0% +savings as the residual just like when +you want to model work you solve for + + align:start position:0% +you want to model work you solve for + + + align:start position:0% +you want to model work you solve for +leisure and get work as the + + align:start position:0% +leisure and get work as the + + + align:start position:0% +leisure and get work as the +residual now let's ask what happens when + + align:start position:0% +residual now let's ask what happens when + + + align:start position:0% +residual now let's ask what happens when +the interest rate goes up okay once + + align:start position:0% +the interest rate goes up okay once + + + align:start position:0% +the interest rate goes up okay once +again I'm sorry I don't have time for + + align:start position:0% +again I'm sorry I don't have time for + + + align:start position:0% +again I'm sorry I don't have time for +the math here but we'll do it in section + + align:start position:0% +the math here but we'll do it in section + + + align:start position:0% +the math here but we'll do it in section +on Friday let's ask what happens when + + align:start position:0% +on Friday let's ask what happens when + + + align:start position:0% +on Friday let's ask what happens when +the interest rate goes up will we move + + align:start position:0% +the interest rate goes up will we move + + + align:start position:0% +the interest rate goes up will we move +from bc1 to + + align:start position:0% +from bc1 to + + + align:start position:0% +from bc1 to +bc2 that has guess what two + + align:start position:0% +bc2 that has guess what two + + + align:start position:0% +bc2 that has guess what two +effects on the one hand you get the + + align:start position:0% +effects on the one hand you get the + + + align:start position:0% +effects on the one hand you get the +substitution + + align:start position:0% +substitution + + + align:start position:0% +substitution +effect the substitution effect is the + + align:start position:0% +effect the substitution effect is the + + + align:start position:0% +effect the substitution effect is the +price of First Period consumption has + + align:start position:0% +price of First Period consumption has + + + align:start position:0% +price of First Period consumption has +gone up so you want to do less of it + + align:start position:0% +gone up so you want to do less of it + + + align:start position:0% +gone up so you want to do less of it +focus on that remember I'm not talking + + align:start position:0% +focus on that remember I'm not talking + + + align:start position:0% +focus on that remember I'm not talking +about savings I'm not talking about + + align:start position:0% +about savings I'm not talking about + + + align:start position:0% +about savings I'm not talking about +second period consumption the subsid + + align:start position:0% +second period consumption the subsid + + + align:start position:0% +second period consumption the subsid +income effects are purely in terms of + + align:start position:0% +income effects are purely in terms of + + + align:start position:0% +income effects are purely in terms of +first period consumption C1 is what + + align:start position:0% +first period consumption C1 is what + + + align:start position:0% +first period consumption C1 is what +you're maximizing over here the price of + + align:start position:0% +you're maximizing over here the price of + + + align:start position:0% +you're maximizing over here the price of +First Period consumption is gone up why + + align:start position:0% +First Period consumption is gone up why + + + align:start position:0% +First Period consumption is gone up why +is it gone up because the opportunity + + align:start position:0% +is it gone up because the opportunity + + + align:start position:0% +is it gone up because the opportunity +cost's gone up you can have more in + + align:start position:0% +cost's gone up you can have more in + + + align:start position:0% +cost's gone up you can have more in +Period two by Saving more so the + + align:start position:0% +Period two by Saving more so the + + + align:start position:0% +Period two by Saving more so the +substitution effect necessarily says you + + align:start position:0% +substitution effect necessarily says you + + + align:start position:0% +substitution effect necessarily says you +have less period one + + align:start position:0% +have less period one + + + align:start position:0% +have less period one +consumption but what about the income + + align:start position:0% +consumption but what about the income + + + align:start position:0% +consumption but what about the income +effect well consumption in Period two is + + align:start position:0% +effect well consumption in Period two is + + + align:start position:0% +effect well consumption in Period two is +a normal + + align:start position:0% +a normal + + + align:start position:0% +a normal +good I'm sorry consumption sorry + + align:start position:0% +good I'm sorry consumption sorry + + + align:start position:0% +good I'm sorry consumption sorry +consumption period one is a normal good + + align:start position:0% +consumption period one is a normal good + + + align:start position:0% +consumption period one is a normal good +cons period one is a normal good and are + + align:start position:0% +cons period one is a normal good and are + + + align:start position:0% +cons period one is a normal good and are +you richer or + + align:start position:0% +you richer or + + + align:start position:0% +you richer or +poor if the rate goes + + align:start position:0% +poor if the rate goes + + + align:start position:0% +poor if the rate goes +up are you effectively richer or poor + + align:start position:0% +up are you effectively richer or poor + + + align:start position:0% +up are you effectively richer or poor +effectively go ahead you know richer + + align:start position:0% +effectively go ahead you know richer + + + align:start position:0% +effectively go ahead you know richer +you're effectively richer because every + + align:start position:0% +you're effectively richer because every + + + align:start position:0% +you're effectively richer because every +dollar of savings yields more + + align:start position:0% +dollar of savings yields more + + + align:start position:0% +dollar of savings yields more +money so the income effect says since + + align:start position:0% +money so the income effect says since + + + align:start position:0% +money so the income effect says since +you're richer you want more of + + align:start position:0% +you're richer you want more of + + + align:start position:0% +you're richer you want more of +everything what's one of the things you + + align:start position:0% +everything what's one of the things you + + + align:start position:0% +everything what's one of the things you +want more of + + align:start position:0% +want more of + + + align:start position:0% +want more of +C1 so the income effect goes the other + + align:start position:0% +C1 so the income effect goes the other + + + align:start position:0% +C1 so the income effect goes the other +way you get the same sort of GIF and + + align:start position:0% +way you get the same sort of GIF and + + + align:start position:0% +way you get the same sort of GIF and +good effects without + + align:start position:0% +good effects without + + + align:start position:0% +good effects without +weirdness so actually whether a higher + + align:start position:0% +weirdness so actually whether a higher + + + align:start position:0% +weirdness so actually whether a higher +interest rate raised or low and saving + + align:start position:0% +interest rate raised or low and saving + + + align:start position:0% +interest rate raised or low and saving +is ambiguous once again think of the + + align:start position:0% +is ambiguous once again think of the + + + align:start position:0% +is ambiguous once again think of the +intuition it's even easier intuition + + align:start position:0% +intuition it's even easier intuition + + + align:start position:0% +intuition it's even easier intuition +here you're a kid you want a bike the + + align:start position:0% +here you're a kid you want a bike the + + + align:start position:0% +here you're a kid you want a bike the +bike's going to cost 200 bucks you can + + align:start position:0% +bike's going to cost 200 bucks you can + + + align:start position:0% +bike's going to cost 200 bucks you can +earn 10 bucks an hour so you work 20 + + align:start position:0% +earn 10 bucks an hour so you work 20 + + + align:start position:0% +earn 10 bucks an hour so you work 20 +hours to get the bike then you quit well + + align:start position:0% +hours to get the bike then you quit well + + + align:start position:0% +hours to get the bike then you quit well +if you earn 15 bucks an hour you work + + align:start position:0% +if you earn 15 bucks an hour you work + + + align:start position:0% +if you earn 15 bucks an hour you work +few hours because all you want is the + + align:start position:0% +few hours because all you want is the + + + align:start position:0% +few hours because all you want is the +bike that would be a that would be a + + align:start position:0% +bike that would be a that would be a + + + align:start position:0% +bike that would be a that would be a +downward sloping supply curve in that + + align:start position:0% +downward sloping supply curve in that + + + align:start position:0% +downward sloping supply curve in that +case the interest rate rise would cause + + align:start position:0% +case the interest rate rise would cause + + + align:start position:0% +case the interest rate rise would cause +you I'm not working I'm sorry let me + + align:start position:0% +you I'm not working I'm sorry let me + + + align:start position:0% +you I'm not working I'm sorry let me +back up I did working going too fast + + align:start position:0% +back up I did working going too fast + + + align:start position:0% +back up I did working going too fast +here you want a bike it's 200 bucks so + + align:start position:0% +here you want a bike it's 200 bucks so + + + align:start position:0% +here you want a bike it's 200 bucks so +you got to save + + align:start position:0% +you got to save + + + align:start position:0% +you got to save +$200 um you got to save $200 so if the + + align:start position:0% +$200 um you got to save $200 so if the + + + align:start position:0% +$200 um you got to save $200 so if the +interest rate is + + align:start position:0% +interest rate is + + + align:start position:0% +interest rate is +% then you have to save say you know one + + align:start position:0% +% then you have to save say you know one + + + align:start position:0% +% then you have to save say you know one +you know uh you know 180 roughly this + + align:start position:0% +you know uh you know 180 roughly this + + + align:start position:0% +you know uh you know 180 roughly this +year okay to get the bike next year this + + align:start position:0% +year okay to get the bike next year this + + + align:start position:0% +year okay to get the bike next year this +rate 20% you'll have to save about 160 + + align:start position:0% +rate 20% you'll have to save about 160 + + + align:start position:0% +rate 20% you'll have to save about 160 +this year to get the bike next year okay + + align:start position:0% +this year to get the bike next year okay + + + align:start position:0% +this year to get the bike next year okay +that's a b forget my old example I was + + align:start position:0% +that's a b forget my old example I was + + + align:start position:0% +that's a b forget my old example I was +on labor so if you want the bike next + + align:start position:0% +on labor so if you want the bike next + + + align:start position:0% +on labor so if you want the bike next +year for 200 bucks and this rates 10% + + align:start position:0% +year for 200 bucks and this rates 10% + + + align:start position:0% +year for 200 bucks and this rates 10% +you got to save 180 but 20% you got to + + align:start position:0% +you got to save 180 but 20% you got to + + + align:start position:0% +you got to save 180 but 20% you got to +save 160 so you're actually savings goes + + align:start position:0% +save 160 so you're actually savings goes + + + align:start position:0% +save 160 so you're actually savings goes +down a higher interest rate causes + + align:start position:0% +down a higher interest rate causes + + + align:start position:0% +down a higher interest rate causes +savings to go down that would be a + + align:start position:0% +savings to go down that would be a + + + align:start position:0% +savings to go down that would be a +downward sloping supply curve so just + + align:start position:0% +downward sloping supply curve so just + + + align:start position:0% +downward sloping supply curve so just +like labor Supply we don't know which + + align:start position:0% +like labor Supply we don't know which + + + align:start position:0% +like labor Supply we don't know which +way the capital supply curve goes and + + align:start position:0% +way the capital supply curve goes and + + + align:start position:0% +way the capital supply curve goes and +here unfortunately like unfortunately + + align:start position:0% +here unfortunately like unfortunately + + + align:start position:0% +here unfortunately like unfortunately +unlike labor Supply we don't even have + + align:start position:0% +unlike labor Supply we don't even have + + + align:start position:0% +unlike labor Supply we don't even have +good evidence we pretty much know that + + align:start position:0% +good evidence we pretty much know that + + + align:start position:0% +good evidence we pretty much know that +labor Supply curves slope up but are + + align:start position:0% +labor Supply curves slope up but are + + + align:start position:0% +labor Supply curves slope up but are +almost + + align:start position:0% +almost + + + align:start position:0% +almost +vertical with with capital Supply curves + + align:start position:0% +vertical with with capital Supply curves + + + align:start position:0% +vertical with with capital Supply curves +we actually don't + + align:start position:0% +we actually don't + + + align:start position:0% +we actually don't +know it's a real empirical weakness in + + align:start position:0% +know it's a real empirical weakness in + + + align:start position:0% +know it's a real empirical weakness in +economics so we are going to go ahead + + align:start position:0% +economics so we are going to go ahead + + + align:start position:0% +economics so we are going to go ahead +and assume substitution effects Dominate + + align:start position:0% +and assume substitution effects Dominate + + + align:start position:0% +and assume substitution effects Dominate +and generally draw upward slope opening + + align:start position:0% +and generally draw upward slope opening + + + align:start position:0% +and generally draw upward slope opening +Capital Supply Curves in this course but + + align:start position:0% +Capital Supply Curves in this course but + + + align:start position:0% +Capital Supply Curves in this course but +unfortunately we don't really know what + + align:start position:0% +unfortunately we don't really know what + + + align:start position:0% +unfortunately we don't really know what +the capital supply curve looks like okay + + align:start position:0% +the capital supply curve looks like okay + + + align:start position:0% +the capital supply curve looks like okay +I will stop there and we'll come back uh + + align:start position:0% +I will stop there and we'll come back uh + + + align:start position:0% +I will stop there and we'll come back uh +next time and just continue discussing + + align:start position:0% +next time and just continue discussing + + + align:start position:0% +next time and just continue discussing +we'll discuss how you should invest your + + align:start position:0% +we'll discuss how you should invest your + + + align:start position:0% +we'll discuss how you should invest your +money so come back next time and learn + + align:start position:0% +money so come back next time and learn + + + align:start position:0% +money so come back next time and learn +how you should invest your money \ No newline at end of file diff --git a/_WwudFI6YRs.txt b/_WwudFI6YRs.txt new file mode 100644 index 0000000000000000000000000000000000000000..1381a9bfd92eeebbadf800f208658ef3c66e2c25 --- /dev/null +++ b/_WwudFI6YRs.txt @@ -0,0 +1,1547 @@ +align:start position:0% + +so I want to give to demystify a little + + align:start position:0% +so I want to give to demystify a little + + + align:start position:0% +so I want to give to demystify a little +this equations we sometimes use the + + align:start position:0% +this equations we sometimes use the + + + align:start position:0% +this equations we sometimes use the +basis to show everything that is + + align:start position:0% +basis to show everything that is + + + align:start position:0% +basis to show everything that is +happening so we have a good basis so + + align:start position:0% +happening so we have a good basis so + + + align:start position:0% +happening so we have a good basis so +let's look at it so how does it all look + + align:start position:0% + + + + align:start position:0% + +thus this look in an orthonormal basis + + align:start position:0% +thus this look in an orthonormal basis + + + align:start position:0% +thus this look in an orthonormal basis +so which basis well you have one h0 was + + align:start position:0% +so which basis well you have one h0 was + + + align:start position:0% +so which basis well you have one h0 was +supposed to be down so we'll call these + + align:start position:0% +supposed to be down so we'll call these + + + align:start position:0% +supposed to be down so we'll call these +states and these are the eigenstates of + + align:start position:0% +states and these are the eigenstates of + + + align:start position:0% +states and these are the eigenstates of +h0 will have e n we could put a 0 we + + align:start position:0% +h0 will have e n we could put a 0 we + + + align:start position:0% +h0 will have e n we could put a 0 we +used to have that 0 there but since + + align:start position:0% +used to have that 0 there but since + + + align:start position:0% +used to have that 0 there but since +we're never gonna try to solve this + + align:start position:0% +we're never gonna try to solve this + + + align:start position:0% +we're never gonna try to solve this +equation in a different way as time goes + + align:start position:0% +equation in a different way as time goes + + + align:start position:0% +equation in a different way as time goes +on we're not the time-dependent system I + + align:start position:0% +on we're not the time-dependent system I + + + align:start position:0% +on we're not the time-dependent system I +said you doesn't have energy eigenstates + + align:start position:0% +said you doesn't have energy eigenstates + + + align:start position:0% +said you doesn't have energy eigenstates +so a perturbation theory is not gonna be + + align:start position:0% +so a perturbation theory is not gonna be + + + align:start position:0% +so a perturbation theory is not gonna be +about perturbing this energy so I will + + align:start position:0% +about perturbing this energy so I will + + + align:start position:0% +about perturbing this energy so I will +erase it + + align:start position:0% +erase it + + + align:start position:0% +erase it +E and there will be no confusion that's + + align:start position:0% +E and there will be no confusion that's + + + align:start position:0% +E and there will be no confusion that's +never gonna change now I'm gonna write + + align:start position:0% +never gonna change now I'm gonna write + + + align:start position:0% +never gonna change now I'm gonna write +an equation that may seem a little + + align:start position:0% +an equation that may seem a little + + + align:start position:0% +an equation that may seem a little +strange we want to solve for this potato + + align:start position:0% +strange we want to solve for this potato + + + align:start position:0% +strange we want to solve for this potato +so let's write an answer for this side + + align:start position:0% +so let's write an answer for this side + + + align:start position:0% +so let's write an answer for this side +tilde of T is gonna be the following sum + + align:start position:0% +tilde of T is gonna be the following sum + + + align:start position:0% +tilde of T is gonna be the following sum +over n CN and + + align:start position:0% + + + + align:start position:0% + +if CNS are constant this is definitely + + align:start position:0% +if CNS are constant this is definitely + + + align:start position:0% +if CNS are constant this is definitely +not right these states must have some + + align:start position:0% +not right these states must have some + + + align:start position:0% +not right these states must have some +time dependence so at least I should put + + align:start position:0% +time dependence so at least I should put + + + align:start position:0% +time dependence so at least I should put +the time dependence here + + align:start position:0% +the time dependence here + + + align:start position:0% +the time dependence here +but even that this sounds a little wrong + + align:start position:0% +but even that this sounds a little wrong + + + align:start position:0% +but even that this sounds a little wrong +a priori you knew that in time + + align:start position:0% +a priori you knew that in time + + + align:start position:0% +a priori you knew that in time +independent problems you can always + + align:start position:0% +independent problems you can always + + + align:start position:0% +independent problems you can always +write a state as a superposition of your + + align:start position:0% +write a state as a superposition of your + + + align:start position:0% +write a state as a superposition of your +energy eigenstates so now this is the + + align:start position:0% +energy eigenstates so now this is the + + + align:start position:0% +energy eigenstates so now this is the +interacting picture we have not any more + + align:start position:0% +interacting picture we have not any more + + + align:start position:0% +interacting picture we have not any more +energy eigenstates in any sense + + align:start position:0% +energy eigenstates in any sense + + + align:start position:0% +energy eigenstates in any sense +can I write this does this make sense + + align:start position:0% +can I write this does this make sense + + + align:start position:0% +can I write this does this make sense +still well the answer is yes you can and + + align:start position:0% +still well the answer is yes you can and + + + align:start position:0% +still well the answer is yes you can and +the reason is that whatever you can say + + align:start position:0% +the reason is that whatever you can say + + + align:start position:0% +the reason is that whatever you can say +about this energy eigenstate they apply + + align:start position:0% +about this energy eigenstate they apply + + + align:start position:0% +about this energy eigenstate they apply +for early times they apply for late + + align:start position:0% +for early times they apply for late + + + align:start position:0% +for early times they apply for late +times they anyway exist there are a + + align:start position:0% +times they anyway exist there are a + + + align:start position:0% +times they anyway exist there are a +basis and what I said they are a basis + + align:start position:0% +basis and what I said they are a basis + + + align:start position:0% +basis and what I said they are a basis +so any wave function can be written in + + align:start position:0% +so any wave function can be written in + + + align:start position:0% +so any wave function can be written in +terms of them so if I look at side tilde + + align:start position:0% +terms of them so if I look at side tilde + + + align:start position:0% +terms of them so if I look at side tilde +time one second I should be able to find + + align:start position:0% +time one second I should be able to find + + + align:start position:0% +time one second I should be able to find +numbers that make this possible and if I + + align:start position:0% +numbers that make this possible and if I + + + align:start position:0% +numbers that make this possible and if I +look at it at two seconds I will find + + align:start position:0% +look at it at two seconds I will find + + + align:start position:0% +look at it at two seconds I will find +another set of numbers and make it + + align:start position:0% +another set of numbers and make it + + + align:start position:0% +another set of numbers and make it +possible so by the fact that I've + + align:start position:0% +possible so by the fact that I've + + + align:start position:0% +possible so by the fact that I've +included here a time dependence for the + + align:start position:0% +included here a time dependence for the + + + align:start position:0% +included here a time dependence for the +coefficients it is possible to write + + align:start position:0% +coefficients it is possible to write + + + align:start position:0% +coefficients it is possible to write +this these coefficients change in time + + align:start position:0% +this these coefficients change in time + + + align:start position:0% +this these coefficients change in time +in strange ways but that's our unknown + + align:start position:0% +in strange ways but that's our unknown + + + align:start position:0% +in strange ways but that's our unknown +if the if I knew how they change in time + + align:start position:0% +if the if I knew how they change in time + + + align:start position:0% +if the if I knew how they change in time +I would have solved the problem I don't + + align:start position:0% +I would have solved the problem I don't + + + align:start position:0% +I would have solved the problem I don't +know how they change in time but in + + align:start position:0% +know how they change in time but in + + + align:start position:0% +know how they change in time but in +general we will try to find for this + + align:start position:0% +general we will try to find for this + + + align:start position:0% +general we will try to find for this +coefficient so if you have side till + + align:start position:0% +coefficient so if you have side till + + + align:start position:0% +coefficient so if you have side till +that you know at the end of the day your + + align:start position:0% +that you know at the end of the day your + + + align:start position:0% +that you know at the end of the day your +goal is Phi of T so what is Phi of T + + align:start position:0% + + + + align:start position:0% + +sigh of tea from this blackboard is the + + align:start position:0% +sigh of tea from this blackboard is the + + + align:start position:0% +sigh of tea from this blackboard is the +action of this operator on-site ilda + + align:start position:0% +action of this operator on-site ilda + + + align:start position:0% +action of this operator on-site ilda +that operator moves through the + + align:start position:0% +that operator moves through the + + + align:start position:0% +that operator moves through the +constants and through the sum and with + + align:start position:0% +constants and through the sum and with + + + align:start position:0% +constants and through the sum and with +the n states eigenstates of H 0 this + + align:start position:0% +the n states eigenstates of H 0 this + + + align:start position:0% +the n states eigenstates of H 0 this +just gives me minus AI e n T over H bar + + align:start position:0% +just gives me minus AI e n T over H bar + + + align:start position:0% +just gives me minus AI e n T over H bar +and and this expansion should make you + + align:start position:0% +and and this expansion should make you + + + align:start position:0% +and and this expansion should make you +feel good you say ok here it is these + + align:start position:0% +feel good you say ok here it is these + + + align:start position:0% +feel good you say ok here it is these +are my states my state in the my + + align:start position:0% +are my states my state in the my + + + align:start position:0% +are my states my state in the my +time-dependent wave function let's say + + align:start position:0% +time-dependent wave function let's say + + + align:start position:0% +time-dependent wave function let's say +and it's given by this formula if I + + align:start position:0% +and it's given by this formula if I + + + align:start position:0% +and it's given by this formula if I +didn't have a delta H we know that + + align:start position:0% +didn't have a delta H we know that + + + align:start position:0% +didn't have a delta H we know that +without a delta h sy tilde is constant + + align:start position:0% +without a delta h sy tilde is constant + + + align:start position:0% +without a delta h sy tilde is constant +so the c ends would be constant if + + align:start position:0% +so the c ends would be constant if + + + align:start position:0% +so the c ends would be constant if +there's no Delta H and if the C ends are + + align:start position:0% +there's no Delta H and if the C ends are + + + align:start position:0% +there's no Delta H and if the C ends are +continent there's no Delta H that's + + align:start position:0% +continent there's no Delta H that's + + + align:start position:0% +continent there's no Delta H that's +exactly how energy eigenstates evolve in + + align:start position:0% +exactly how energy eigenstates evolve in + + + align:start position:0% +exactly how energy eigenstates evolve in +time they are evolving with the + + align:start position:0% +time they are evolving with the + + + align:start position:0% +time they are evolving with the +Exponential's of the action of H 0 so + + align:start position:0% +Exponential's of the action of H 0 so + + + align:start position:0% +Exponential's of the action of H 0 so +this is consistent with all you know if + + align:start position:0% +this is consistent with all you know if + + + align:start position:0% +this is consistent with all you know if +Delta H turns on the C ends are gonna + + align:start position:0% +Delta H turns on the C ends are gonna + + + align:start position:0% +Delta H turns on the C ends are gonna +choir time dependence and we will know + + align:start position:0% +choir time dependence and we will know + + + align:start position:0% +choir time dependence and we will know +what the state is doing so this is good + + align:start position:0% +what the state is doing so this is good + + + align:start position:0% +what the state is doing so this is good +so let's plug into the new Schrodinger + + align:start position:0% +so let's plug into the new Schrodinger + + + align:start position:0% +so let's plug into the new Schrodinger +equation this expansion and this is our + + align:start position:0% +equation this expansion and this is our + + + align:start position:0% +equation this expansion and this is our +new sir in your equation so what do we + + align:start position:0% +new sir in your equation so what do we + + + align:start position:0% +new sir in your equation so what do we +get I get IH bar D DT of this I'll write + + align:start position:0% +get I get IH bar D DT of this I'll write + + + align:start position:0% +get I get IH bar D DT of this I'll write +it here with a sum I'll change to letter + + align:start position:0% +it here with a sum I'll change to letter + + + align:start position:0% +it here with a sum I'll change to letter +m bc m + + align:start position:0% +m bc m + + + align:start position:0% +m bc m +are these dots C M of T dot for time + + align:start position:0% +are these dots C M of T dot for time + + + align:start position:0% +are these dots C M of T dot for time +derivative many time use dot so I'm + + align:start position:0% +derivative many time use dot so I'm + + + align:start position:0% +derivative many time use dot so I'm +taking the time derivative of tried + + align:start position:0% +taking the time derivative of tried + + + align:start position:0% +taking the time derivative of tried +tilde as in the Schrodinger equation I + + align:start position:0% +tilde as in the Schrodinger equation I + + + align:start position:0% +tilde as in the Schrodinger equation I +go here CM m and this is supposed to be + + align:start position:0% +go here CM m and this is supposed to be + + + align:start position:0% +go here CM m and this is supposed to be +equal to Delta H tilde times this same + + align:start position:0% +equal to Delta H tilde times this same + + + align:start position:0% +equal to Delta H tilde times this same +state so it's going to be sum over and C + + align:start position:0% +state so it's going to be sum over and C + + + align:start position:0% +state so it's going to be sum over and C +n of T Delta H tilde n so this is the + + align:start position:0% +n of T Delta H tilde n so this is the + + + align:start position:0% +n of T Delta H tilde n so this is the +Schrodinger equation for this state I'm + + align:start position:0% +Schrodinger equation for this state I'm + + + align:start position:0% +Schrodinger equation for this state I'm +we're now looking at the Schrodinger + + align:start position:0% +we're now looking at the Schrodinger + + + align:start position:0% +we're now looking at the Schrodinger +equation in a basis because that may be + + align:start position:0% +equation in a basis because that may be + + + align:start position:0% +equation in a basis because that may be +a good way to solve it + + align:start position:0% + + + + align:start position:0% + +well one way to solve it is to do in the + + align:start position:0% +well one way to solve it is to do in the + + + align:start position:0% +well one way to solve it is to do in the +right hand side a complete set introduce + + align:start position:0% +right hand side a complete set introduce + + + align:start position:0% +right hand side a complete set introduce +a complete sets of states so I'll put + + align:start position:0% +a complete sets of states so I'll put + + + align:start position:0% +a complete sets of states so I'll put +the sum over m m m and this whole sum + + align:start position:0% +the sum over m m m and this whole sum + + + align:start position:0% +the sum over m m m and this whole sum +over n C and of P Delta H and so this + + align:start position:0% +over n C and of P Delta H and so this + + + align:start position:0% +over n C and of P Delta H and so this +will be equal to sum over m the M is + + align:start position:0% +will be equal to sum over m the M is + + + align:start position:0% +will be equal to sum over m the M is +here and sum over n the bra can go all + + align:start position:0% +here and sum over n the bra can go all + + + align:start position:0% +here and sum over n the bra can go all +the way in and you write C n of T M + + align:start position:0% +the way in and you write C n of T M + + + align:start position:0% +the way in and you write C n of T M +Delta H + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so this is our Schrodinger equation + + align:start position:0% +so this is our Schrodinger equation + + + align:start position:0% +so this is our Schrodinger equation +still and now it's kind of in a nice way + + align:start position:0% +still and now it's kind of in a nice way + + + align:start position:0% +still and now it's kind of in a nice way +in which we have similar letters on both + + align:start position:0% +in which we have similar letters on both + + + align:start position:0% +in which we have similar letters on both +sides a little bit of notation of I'll + + align:start position:0% +sides a little bit of notation of I'll + + + align:start position:0% +sides a little bit of notation of I'll +call this Delta H tilde M and we've done + + align:start position:0% +call this Delta H tilde M and we've done + + + align:start position:0% +call this Delta H tilde M and we've done +that in perturbation theory many many + + align:start position:0% +that in perturbation theory many many + + + align:start position:0% +that in perturbation theory many many +times so what is our equation well + + align:start position:0% +times so what is our equation well + + + align:start position:0% +times so what is our equation well +compare terms with equal value of the + + align:start position:0% +compare terms with equal value of the + + + align:start position:0% +compare terms with equal value of the +function in front of the state M so we + + align:start position:0% +function in front of the state M so we + + + align:start position:0% +function in front of the state M so we +get IH bar C m dot of T is equal to the + + align:start position:0% +get IH bar C m dot of T is equal to the + + + align:start position:0% +get IH bar C m dot of T is equal to the +sum over n CN or Delta H MN c n of t + + align:start position:0% + + + + align:start position:0% + +that's it it's a nice-looking equation + + align:start position:0% +that's it it's a nice-looking equation + + + align:start position:0% +that's it it's a nice-looking equation +it's a couple set of differential + + align:start position:0% +it's a couple set of differential + + + align:start position:0% +it's a couple set of differential +equations for an infinite set of + + align:start position:0% +equations for an infinite set of + + + align:start position:0% +equations for an infinite set of +functions in which the derivatives are + + align:start position:0% +functions in which the derivatives are + + + align:start position:0% +functions in which the derivatives are +obtained in terms of the Hamiltonian + + align:start position:0% +obtained in terms of the Hamiltonian + + + align:start position:0% +obtained in terms of the Hamiltonian +matrix elements for the transition + + align:start position:0% +matrix elements for the transition + + + align:start position:0% +matrix elements for the transition +Hamiltonian for the perturbation times + + align:start position:0% +Hamiltonian for the perturbation times + + + align:start position:0% +Hamiltonian for the perturbation times +these functions they're a little more + + align:start position:0% +these functions they're a little more + + + align:start position:0% +these functions they're a little more +notation here in in the sense of just + + align:start position:0% +notation here in in the sense of just + + + align:start position:0% +notation here in in the sense of just +understanding the structure of that + + align:start position:0% +understanding the structure of that + + + align:start position:0% +understanding the structure of that +matrix element that's useful because in + + align:start position:0% +matrix element that's useful because in + + + align:start position:0% +matrix element that's useful because in +practice all the tilde things at the end + + align:start position:0% +practice all the tilde things at the end + + + align:start position:0% +practice all the tilde things at the end +of the day groups we don't want them we + + align:start position:0% +of the day groups we don't want them we + + + align:start position:0% +of the day groups we don't want them we +want the original ones things without + + align:start position:0% +want the original ones things without + + + align:start position:0% +want the original ones things without +tilde and we always look for them so + + align:start position:0% +tilde and we always look for them so + + + align:start position:0% +tilde and we always look for them so +what is this matrix element Delta H m + + align:start position:0% +what is this matrix element Delta H m + + + align:start position:0% +what is this matrix element Delta H m +and tilde is M Delta H tilde and but + + align:start position:0% +and tilde is M Delta H tilde and but + + + align:start position:0% +and tilde is M Delta H tilde and but +remember what Delta H tilde was you have + + align:start position:0% +remember what Delta H tilde was you have + + + align:start position:0% +remember what Delta H tilde was you have +it here so we have m e to the IH 0 T + + align:start position:0% +it here so we have m e to the IH 0 T + + + align:start position:0% +it here so we have m e to the IH 0 T +over H bar Delta H e to the minus I h 0 + + align:start position:0% +over H bar Delta H e to the minus I h 0 + + + align:start position:0% +over H bar Delta H e to the minus I h 0 +T over H bar and that's no problem + + align:start position:0% +T over H bar and that's no problem + + + align:start position:0% +T over H bar and that's no problem +everything is good here because those + + align:start position:0% +everything is good here because those + + + align:start position:0% +everything is good here because those +are eigenstates so we know how much you + + align:start position:0% +are eigenstates so we know how much you + + + align:start position:0% +are eigenstates so we know how much you +get by letting this act on that state + + align:start position:0% +get by letting this act on that state + + + align:start position:0% +get by letting this act on that state +and that other exponential act on the + + align:start position:0% +and that other exponential act on the + + + align:start position:0% +and that other exponential act on the +state on the right so what do we get e + + align:start position:0% +state on the right so what do we get e + + + align:start position:0% +state on the right so what do we get e +to the i e + + align:start position:0% +to the i e + + + align:start position:0% +to the i e +em T over H bar and from the other one + + align:start position:0% +em T over H bar and from the other one + + + align:start position:0% +em T over H bar and from the other one +e n P over H bar like this the two + + align:start position:0% +e n P over H bar like this the two + + + align:start position:0% +e n P over H bar like this the two +Exponential's give you that and then you + + align:start position:0% +Exponential's give you that and then you + + + align:start position:0% +Exponential's give you that and then you +have just Delta H your original + + align:start position:0% +have just Delta H your original + + + align:start position:0% +have just Delta H your original +perturbation between states of the + + align:start position:0% +perturbation between states of the + + + align:start position:0% +perturbation between states of the +Hamiltonian so you have here and M I'll + + align:start position:0% +Hamiltonian so you have here and M I'll + + + align:start position:0% +Hamiltonian so you have here and M I'll +write it this way Delta H and and just + + align:start position:0% +write it this way Delta H and and just + + + align:start position:0% +write it this way Delta H and and just +without the tilde which is M Delta H + + align:start position:0% + + + + align:start position:0% + +most people call this the frequency m + + align:start position:0% +most people call this the frequency m + + + align:start position:0% +most people call this the frequency m +and e over H bar is a frequency so + + align:start position:0% +and e over H bar is a frequency so + + + align:start position:0% +and e over H bar is a frequency so +harmonic oscillator reminds of you of + + align:start position:0% +harmonic oscillator reminds of you of + + + align:start position:0% +harmonic oscillator reminds of you of +that a equal H bar Omega and for easier + + align:start position:0% +that a equal H bar Omega and for easier + + + align:start position:0% +that a equal H bar Omega and for easier +writing you write an Omega M n so this + + align:start position:0% +writing you write an Omega M n so this + + + align:start position:0% +writing you write an Omega M n so this +becomes e to the I Omega m and T times + + align:start position:0% +becomes e to the I Omega m and T times + + + align:start position:0% +becomes e to the I Omega m and T times +Delta H M so this is kind of nice + + align:start position:0% +Delta H M so this is kind of nice + + + align:start position:0% +Delta H M so this is kind of nice +notation so this matrix elements there + + align:start position:0% +notation so this matrix elements there + + + align:start position:0% +notation so this matrix elements there +of not well I'll write again the + + align:start position:0% +of not well I'll write again the + + + align:start position:0% +of not well I'll write again the +equation I h-bar C m dot of T would be + + align:start position:0% +equation I h-bar C m dot of T would be + + + align:start position:0% +equation I h-bar C m dot of T would be +the sum over n of e to the I Omega m and + + align:start position:0% +the sum over n of e to the I Omega m and + + + align:start position:0% +the sum over n of e to the I Omega m and +T Delta H M and C n of K + + align:start position:0% + + + + align:start position:0% + +that same equation has been rewritten in + + align:start position:0% +that same equation has been rewritten in + + + align:start position:0% +that same equation has been rewritten in +the viewpoint of this where we simplify + + align:start position:0% +the viewpoint of this where we simplify + + + align:start position:0% +the viewpoint of this where we simplify +the tilde and we can refer everything to + + align:start position:0% +the tilde and we can refer everything to + + + align:start position:0% +the tilde and we can refer everything to +our original basis so in a sense of I + + align:start position:0% +our original basis so in a sense of I + + + align:start position:0% +our original basis so in a sense of I +think this should be mystify things + + align:start position:0% +think this should be mystify things + + + align:start position:0% +think this should be mystify things +what's the situation + + align:start position:0% +what's the situation + + + align:start position:0% +what's the situation +what has happened is that if you have a + + align:start position:0% +what has happened is that if you have a + + + align:start position:0% +what has happened is that if you have a +basis you write an answer for the wave + + align:start position:0% +basis you write an answer for the wave + + + align:start position:0% +basis you write an answer for the wave +function of this form and the + + align:start position:0% +function of this form and the + + + align:start position:0% +function of this form and the +coefficients are solutions of those + + align:start position:0% +coefficients are solutions of those + + + align:start position:0% +coefficients are solutions of those +differential equations so we've + + align:start position:0% +differential equations so we've + + + align:start position:0% +differential equations so we've +translated the problem to something + + align:start position:0% +translated the problem to something + + + align:start position:0% +translated the problem to something +doable if you have lots of resources a + + align:start position:0% +doable if you have lots of resources a + + + align:start position:0% +doable if you have lots of resources a +computer and you solve coupled + + align:start position:0% +computer and you solve coupled + + + align:start position:0% +computer and you solve coupled +time-dependent differential equations + + align:start position:0% +time-dependent differential equations + + + align:start position:0% +time-dependent differential equations +first order these are not partic well it + + align:start position:0% +first order these are not partic well it + + + align:start position:0% +first order these are not partic well it +all depends how difficult is the time + + align:start position:0% +all depends how difficult is the time + + + align:start position:0% +all depends how difficult is the time +dependence here the exponential is not + + align:start position:0% +dependence here the exponential is not + + + align:start position:0% +dependence here the exponential is not +bad this well it all depends but this + + align:start position:0% +bad this well it all depends but this + + + align:start position:0% +bad this well it all depends but this +can be solved numerically can be solved + + align:start position:0% +can be solved numerically can be solved + + + align:start position:0% +can be solved numerically can be solved +with many methods this has made the + + align:start position:0% +with many methods this has made the + + + align:start position:0% +with many methods this has made the +problem concrete and we're going to try + + align:start position:0% +problem concrete and we're going to try + + + align:start position:0% +problem concrete and we're going to try +to understand how to solve it in cases + + align:start position:0% +to understand how to solve it in cases + + + align:start position:0% +to understand how to solve it in cases +of interest \ No newline at end of file diff --git a/_uNWqE3LS1E.txt b/_uNWqE3LS1E.txt new file mode 100644 index 0000000000000000000000000000000000000000..4fae8deef63d6f2e018984bb244db1d3aa95fd41 --- /dev/null +++ b/_uNWqE3LS1E.txt @@ -0,0 +1,8131 @@ +align:start position:0% + +so in this final lecture I want to think + + align:start position:0% +so in this final lecture I want to think + + + align:start position:0% +so in this final lecture I want to think +on a bit uh sort of + + align:start position:0% +on a bit uh sort of + + + align:start position:0% +on a bit uh sort of +with an eye towards thinking about how + + align:start position:0% +with an eye towards thinking about how + + + align:start position:0% +with an eye towards thinking about how +one might actually make measurements + + align:start position:0% +one might actually make measurements + + + align:start position:0% +one might actually make measurements +that probe the nature of the black hole + + align:start position:0% +that probe the nature of the black hole + + + align:start position:0% +that probe the nature of the black hole +space times I discussed in the previous + + align:start position:0% +space times I discussed in the previous + + + align:start position:0% +space times I discussed in the previous +lecture I'm going to discuss motion in a + + align:start position:0% +lecture I'm going to discuss motion in a + + + align:start position:0% +lecture I'm going to discuss motion in a +black hole space-time we touched this we + + align:start position:0% +black hole space-time we touched this we + + + align:start position:0% +black hole space-time we touched this we +touched on this a little bit in the + + align:start position:0% +touched on this a little bit in the + + + align:start position:0% +touched on this a little bit in the +previous lecture where we discussed the + + align:start position:0% +previous lecture where we discussed the + + + align:start position:0% +previous lecture where we discussed the +motion of radial light rays okay we in + + align:start position:0% +motion of radial light rays okay we in + + + align:start position:0% +motion of radial light rays okay we in +fact used radial light rays as a as a + + align:start position:0% +fact used radial light rays as a as a + + + align:start position:0% +fact used radial light rays as a as a +critical tool for describing the + + align:start position:0% +critical tool for describing the + + + align:start position:0% +critical tool for describing the +property to the space-time we use that + + align:start position:0% +property to the space-time we use that + + + align:start position:0% +property to the space-time we use that +to help us understand the location of + + align:start position:0% +to help us understand the location of + + + align:start position:0% +to help us understand the location of +event horizons but I want to think a + + align:start position:0% +event horizons but I want to think a + + + align:start position:0% +event horizons but I want to think a +little bit more generally what it might + + align:start position:0% +little bit more generally what it might + + + align:start position:0% +little bit more generally what it might +look like if I have material orbiting in + + align:start position:0% +look like if I have material orbiting in + + + align:start position:0% +look like if I have material orbiting in +them in the vicinity of one of these + + align:start position:0% +them in the vicinity of one of these + + + align:start position:0% +them in the vicinity of one of these +black holes what if it's not light what + + align:start position:0% +black holes what if it's not light what + + + align:start position:0% +black holes what if it's not light what +if it's made out of matter and so what + + align:start position:0% +if it's made out of matter and so what + + + align:start position:0% +if it's made out of matter and so what +this is going to boil down to is + + align:start position:0% +this is going to boil down to is + + + align:start position:0% +this is going to boil down to is +understanding the behavior of judy's X + + align:start position:0% +understanding the behavior of judy's X + + + align:start position:0% +understanding the behavior of judy's X +in a black hole space-time and the naive + + align:start position:0% +in a black hole space-time and the naive + + + align:start position:0% +in a black hole space-time and the naive +approach to doing this is not wrong but + + align:start position:0% +approach to doing this is not wrong but + + + align:start position:0% +approach to doing this is not wrong but +naive what you do is you would just take + + align:start position:0% +naive what you do is you would just take + + + align:start position:0% +naive what you do is you would just take +the space-time okay take your Schwarz + + align:start position:0% +the space-time okay take your Schwarz + + + align:start position:0% +the space-time okay take your Schwarz +shield or take your Kerr space-time and + + align:start position:0% +shield or take your Kerr space-time and + + + align:start position:0% +shield or take your Kerr space-time and +turn a very large crank grind out all of + + align:start position:0% +turn a very large crank grind out all of + + + align:start position:0% +turn a very large crank grind out all of +the connection coefficients evaluate the + + align:start position:0% +the connection coefficients evaluate the + + + align:start position:0% +the connection coefficients evaluate the +judie tzuke equation integrate it up + + align:start position:0% +judie tzuke equation integrate it up + + + align:start position:0% +judie tzuke equation integrate it up +solve for the geodesics boom got + + align:start position:0% +solve for the geodesics boom got + + + align:start position:0% +solve for the geodesics boom got +yourself your motion okay and that is + + align:start position:0% +yourself your motion okay and that is + + + align:start position:0% +yourself your motion okay and that is +absolutely correct you can do that using + + align:start position:0% +absolutely correct you can do that using + + + align:start position:0% +absolutely correct you can do that using +your cur space-time or your + + align:start position:0% +your cur space-time or your + + + align:start position:0% +your cur space-time or your +Schwarzschild space-time in fact if you + + align:start position:0% +Schwarzschild space-time in fact if you + + + align:start position:0% +Schwarzschild space-time in fact if you +do that for you can get the connection + + align:start position:0% +do that for you can get the connection + + + align:start position:0% +do that for you can get the connection +coefficients describing this you know + + align:start position:0% +coefficients describing this you know + + + align:start position:0% +coefficients describing this you know +those are relatively easy to work out I + + align:start position:0% +those are relatively easy to work out I + + + align:start position:0% +those are relatively easy to work out I +think they are listed in Carroll and + + align:start position:0% +think they are listed in Carroll and + + + align:start position:0% +think they are listed in Carroll and +equation five point five three according + + align:start position:0% +equation five point five three according + + + align:start position:0% +equation five point five three according +to my notes that may just be for + + align:start position:0% +to my notes that may just be for + + + align:start position:0% +to my notes that may just be for +Schwartz Hill betting right they're all + + align:start position:0% +Schwartz Hill betting right they're all + + + align:start position:0% +Schwartz Hill betting right they're all +listed there and + + align:start position:0% +listed there and + + + align:start position:0% +listed there and +have a blast this approach is not wrong + + align:start position:0% +have a blast this approach is not wrong + + + align:start position:0% +have a blast this approach is not wrong +but my notes say but is not useful + + align:start position:0% +but my notes say but is not useful + + + align:start position:0% +but my notes say but is not useful +that's not really true I'll just say + + align:start position:0% +that's not really true I'll just say + + + align:start position:0% +that's not really true I'll just say +that there is a more useful approach to + + align:start position:0% +that there is a more useful approach to + + + align:start position:0% +that there is a more useful approach to +this a more fruitful approach is to + + align:start position:0% +this a more fruitful approach is to + + + align:start position:0% +this a more fruitful approach is to +exploit the fact that these are highly + + align:start position:0% +exploit the fact that these are highly + + + align:start position:0% +exploit the fact that these are highly +symmetric space times exploit the + + align:start position:0% +symmetric space times exploit the + + + align:start position:0% +symmetric space times exploit the +symmetries and the killing vectors and + + align:start position:0% +symmetries and the killing vectors and + + + align:start position:0% +symmetries and the killing vectors and +see how they can be used to reduce the + + align:start position:0% +see how they can be used to reduce the + + + align:start position:0% +see how they can be used to reduce the +number of degrees of freedom that you + + align:start position:0% +number of degrees of freedom that you + + + align:start position:0% +number of degrees of freedom that you +need to describe in this lecture I'm + + align:start position:0% +need to describe in this lecture I'm + + + align:start position:0% +need to describe in this lecture I'm +going to go through this in quite a bit + + align:start position:0% +going to go through this in quite a bit + + + align:start position:0% +going to go through this in quite a bit +of detail for Swart shield the concepts + + align:start position:0% +of detail for Swart shield the concepts + + + align:start position:0% +of detail for Swart shield the concepts +that I'm going to apply work for cur and + + align:start position:0% +that I'm going to apply work for cur and + + + align:start position:0% +that I'm going to apply work for cur and +for current Neuman as well okay + + align:start position:0% +for current Neuman as well okay + + + align:start position:0% +for current Neuman as well okay +Schwartz Hill is just a little easier to + + align:start position:0% +Schwartz Hill is just a little easier to + + + align:start position:0% +Schwartz Hill is just a little easier to +work with it's something that I can fit + + align:start position:0% +work with it's something that I can fit + + + align:start position:0% +work with it's something that I can fit +into a single lecture in particular one + + align:start position:0% +into a single lecture in particular one + + + align:start position:0% +into a single lecture in particular one +of the nice things about Schwartz Shield + + align:start position:0% +of the nice things about Schwartz Shield + + + align:start position:0% +of the nice things about Schwartz Shield +so let's go ahead and write down that + + align:start position:0% +so let's go ahead and write down that + + + align:start position:0% +so let's go ahead and write down that +space-time + + align:start position:0% + + + + align:start position:0% + +so one of the nice things about Schwartz + + align:start position:0% +so one of the nice things about Schwartz + + + align:start position:0% +so one of the nice things about Schwartz +Shield is it is spherically symmetric + + align:start position:0% + + + + align:start position:0% + +this means I can always rotate + + align:start position:0% +this means I can always rotate + + + align:start position:0% +this means I can always rotate +coordinates such that well let me think + + align:start position:0% +coordinates such that well let me think + + + align:start position:0% +coordinates such that well let me think +about which let's back up for a second + + align:start position:0% +about which let's back up for a second + + + align:start position:0% +about which let's back up for a second +imagine that I have some kind of a body + + align:start position:0% +imagine that I have some kind of a body + + + align:start position:0% +imagine that I have some kind of a body +orbiting a short shield black hole + + align:start position:0% +orbiting a short shield black hole + + + align:start position:0% +orbiting a short shield black hole +spherical symmetry tells me that there + + align:start position:0% +spherical symmetry tells me that there + + + align:start position:0% +spherical symmetry tells me that there +must be some notion of a conserved + + align:start position:0% +must be some notion of a conserved + + + align:start position:0% +must be some notion of a conserved +angular momentum such that that orbit + + align:start position:0% +angular momentum such that that orbit + + + align:start position:0% +angular momentum such that that orbit +always lies within a given plane put it + + align:start position:0% +always lies within a given plane put it + + + align:start position:0% +always lies within a given plane put it +another way because it is spherically + + align:start position:0% +another way because it is spherically + + + align:start position:0% +another way because it is spherically +symmetric there cannot exist a torque + + align:start position:0% + + + + align:start position:0% + +the black hole cannot exert a torque + + align:start position:0% + + + + align:start position:0% + +that changes the orientation of the + + align:start position:0% +that changes the orientation of the + + + align:start position:0% +that changes the orientation of the +orbital plane in particular because it + + align:start position:0% +orbital plane in particular because it + + + align:start position:0% +orbital plane in particular because it +is fairly symmetric there is no unique + + align:start position:0% +is fairly symmetric there is no unique + + + align:start position:0% +is fairly symmetric there is no unique +notion of an equator to this object and + + align:start position:0% +notion of an equator to this object and + + + align:start position:0% +notion of an equator to this object and +so you might as well define any orbits + + align:start position:0% +so you might as well define any orbits + + + align:start position:0% +so you might as well define any orbits +to live in the theta equals PI over 2 + + align:start position:0% +to live in the theta equals PI over 2 + + + align:start position:0% +to live in the theta equals PI over 2 +plane you can always rotate your + + align:start position:0% +plane you can always rotate your + + + align:start position:0% +plane you can always rotate your +coordinates + + align:start position:0% + + + + align:start position:0% + +to put any orbit in the state it equals + + align:start position:0% +to put any orbit in the state it equals + + + align:start position:0% +to put any orbit in the state it equals +PI over two plane it's actually a pretty + + align:start position:0% +PI over two plane it's actually a pretty + + + align:start position:0% +PI over two plane it's actually a pretty +simple exercise I won't do this but if + + align:start position:0% +simple exercise I won't do this but if + + + align:start position:0% +simple exercise I won't do this but if +you start with an orbit that is in the + + align:start position:0% +you start with an orbit that is in the + + + align:start position:0% +you start with an orbit that is in the +theta equals PI over two plane and it is + + align:start position:0% +theta equals PI over two plane and it is + + + align:start position:0% +theta equals PI over two plane and it is +moving such that its initial velocity + + align:start position:0% +moving such that its initial velocity + + + align:start position:0% +moving such that its initial velocity +would keep it in the state equals PI + + align:start position:0% +would keep it in the state equals PI + + + align:start position:0% +would keep it in the state equals PI +over two plane it's a very simple + + align:start position:0% +over two plane it's a very simple + + + align:start position:0% +over two plane it's a very simple +exercise using the judy's equation to + + align:start position:0% +exercise using the judy's equation to + + + align:start position:0% +exercise using the judy's equation to +show that it will always be in the Fit + + align:start position:0% +show that it will always be in the Fit + + + align:start position:0% +show that it will always be in the Fit +equals PI over two plane so spherical + + align:start position:0% +equals PI over two plane so spherical + + + align:start position:0% +equals PI over two plane so spherical +symmetry says you know what let's just + + align:start position:0% +symmetry says you know what let's just + + + align:start position:0% +symmetry says you know what let's just +forget about the theta degree of freedom + + align:start position:0% +forget about the theta degree of freedom + + + align:start position:0% +forget about the theta degree of freedom +I can always define my coordinates in + + align:start position:0% +I can always define my coordinates in + + + align:start position:0% +I can always define my coordinates in +such a way that it lives in the theta + + align:start position:0% +such a way that it lives in the theta + + + align:start position:0% +such a way that it lives in the theta +equals PI over two plane boom I have + + align:start position:0% +equals PI over two plane boom I have + + + align:start position:0% +equals PI over two plane boom I have +reduced my motion from in general being + + align:start position:0% +reduced my motion from in general being + + + align:start position:0% +reduced my motion from in general being +three spatial dimensions to two spatial + + align:start position:0% +three spatial dimensions to two spatial + + + align:start position:0% +three spatial dimensions to two spatial +dimensions that's another one the + + align:start position:0% +dimensions that's another one the + + + align:start position:0% +dimensions that's another one the +reasons why for pedagogical purposes + + align:start position:0% +reasons why for pedagogical purposes + + + align:start position:0% +reasons why for pedagogical purposes +it's nice to start with Schwartz shield + + align:start position:0% +it's nice to start with Schwartz shield + + + align:start position:0% +it's nice to start with Schwartz shield +for ker this is not the case okay Kerr + + align:start position:0% +for ker this is not the case okay Kerr + + + align:start position:0% +for ker this is not the case okay Kerr +is a little bit more complicated you + + align:start position:0% +is a little bit more complicated you + + + align:start position:0% +is a little bit more complicated you +have to treat the theta motion + + align:start position:0% +have to treat the theta motion + + + align:start position:0% +have to treat the theta motion +separately + + align:start position:0% +separately + + + align:start position:0% +separately +you cannot it's not symmetric and so you + + align:start position:0% +you cannot it's not symmetric and so you + + + align:start position:0% +you cannot it's not symmetric and so you +can't do that I have actually spent a + + align:start position:0% +can't do that I have actually spent a + + + align:start position:0% +can't do that I have actually spent a +tremendous amount of my career studying + + align:start position:0% +tremendous amount of my career studying + + + align:start position:0% +tremendous amount of my career studying +the orbits of objects around Kerr black + + align:start position:0% +the orbits of objects around Kerr black + + + align:start position:0% +the orbits of objects around Kerr black +holes and I do have to say that the + + align:start position:0% +holes and I do have to say that the + + + align:start position:0% +holes and I do have to say that the +additional complications that arise from + + align:start position:0% +additional complications that arise from + + + align:start position:0% +additional complications that arise from +this lack of cerissa T they're really + + align:start position:0% +this lack of cerissa T they're really + + + align:start position:0% +this lack of cerissa T they're really +beautiful okay there's an amazing amount + + align:start position:0% +beautiful okay there's an amazing amount + + + align:start position:0% +beautiful okay there's an amazing amount +of fun stuff you can do with it + + align:start position:0% +of fun stuff you can do with it + + + align:start position:0% +of fun stuff you can do with it +you know I mean it's it's there's a + + align:start position:0% +you know I mean it's it's there's a + + + align:start position:0% +you know I mean it's it's there's a +reason why I just keep coming back to + + align:start position:0% +reason why I just keep coming back to + + + align:start position:0% +reason why I just keep coming back to +this research problem and part of it is + + align:start position:0% +this research problem and part of it is + + + align:start position:0% +this research problem and part of it is +it's just bloody fun but if you're + + align:start position:0% +it's just bloody fun but if you're + + + align:start position:0% +it's just bloody fun but if you're +teaching this stuff for the first time + + align:start position:0% +teaching this stuff for the first time + + + align:start position:0% +teaching this stuff for the first time +it's not where you want to begin all + + align:start position:0% +it's not where you want to begin all + + + align:start position:0% +it's not where you want to begin all +right so Swart shield allows us to + + align:start position:0% +right so Swart shield allows us to + + + align:start position:0% +right so Swart shield allows us to +reduce it from a three-dimensional + + align:start position:0% +reduce it from a three-dimensional + + + align:start position:0% +reduce it from a three-dimensional +problem to a two-dimensional problem and + + align:start position:0% +problem to a two-dimensional problem and + + + align:start position:0% +problem to a two-dimensional problem and +Schwartz shield also has to killing + + align:start position:0% +Schwartz shield also has to killing + + + align:start position:0% +Schwartz shield also has to killing +vectors the time derivative of every + + align:start position:0% +vectors the time derivative of every + + + align:start position:0% +vectors the time derivative of every +metric component is equal to zero that + + align:start position:0% +metric component is equal to zero that + + + align:start position:0% +metric component is equal to zero that +means P downstairs T is constant + + align:start position:0% + + + + align:start position:0% + +so there is a time like killing vector + + align:start position:0% +so there is a time like killing vector + + + align:start position:0% +so there is a time like killing vector +so P downstairs T is constant everywhere + + align:start position:0% +so P downstairs T is constant everywhere + + + align:start position:0% +so P downstairs T is constant everywhere +along the orbit it means there exists a + + align:start position:0% +along the orbit it means there exists a + + + align:start position:0% +along the orbit it means there exists a +time like killing vector and so what we + + align:start position:0% +time like killing vector and so what we + + + align:start position:0% +time like killing vector and so what we +do is we associate this with the energy + + align:start position:0% +do is we associate this with the energy + + + align:start position:0% +do is we associate this with the energy +of the orbit we call this up to a minus + + align:start position:0% +of the orbit we call this up to a minus + + + align:start position:0% +of the orbit we call this up to a minus +sign and we choose that minus sign + + align:start position:0% +sign and we choose that minus sign + + + align:start position:0% +sign and we choose that minus sign +because if we imagine orbits a very very + + align:start position:0% +because if we imagine orbits a very very + + + align:start position:0% +because if we imagine orbits a very very +large radius the space time it's nearly + + align:start position:0% +large radius the space time it's nearly + + + align:start position:0% +large radius the space time it's nearly +flat and we want to sort of clear out + + align:start position:0% +flat and we want to sort of clear out + + + align:start position:0% +flat and we want to sort of clear out +the minus sign associates lowering our + + align:start position:0% +the minus sign associates lowering our + + + align:start position:0% +the minus sign associates lowering our +index here we're gonna call that + + align:start position:0% +index here we're gonna call that + + + align:start position:0% +index here we're gonna call that +constant negative of the energy of the + + align:start position:0% +constant negative of the energy of the + + + align:start position:0% +constant negative of the energy of the +orbit the space time is also independent + + align:start position:0% +orbit the space time is also independent + + + align:start position:0% +orbit the space time is also independent +of the angle Phi and so piece of Phi is + + align:start position:0% +of the angle Phi and so piece of Phi is + + + align:start position:0% +of the angle Phi and so piece of Phi is +a constant this means that the + + align:start position:0% +a constant this means that the + + + align:start position:0% +a constant this means that the +space-time has an axial killing factor + + align:start position:0% +space-time has an axial killing factor + + + align:start position:0% +space-time has an axial killing factor +something Associates motions around a + + align:start position:0% +something Associates motions around a + + + align:start position:0% +something Associates motions around a +symmetry axis so I'm gonna call this L + + align:start position:0% +symmetry axis so I'm gonna call this L + + + align:start position:0% +symmetry axis so I'm gonna call this L +well actually I will tend to call it L + + align:start position:0% +well actually I will tend to call it L + + + align:start position:0% +well actually I will tend to call it L +sub Z you can kind of think of this as + + align:start position:0% +sub Z you can kind of think of this as + + + align:start position:0% +sub Z you can kind of think of this as +after I have put everything in the state + + align:start position:0% +after I have put everything in the state + + + align:start position:0% +after I have put everything in the state +equals PI over 2 plane this is like an + + align:start position:0% +equals PI over 2 plane this is like an + + + align:start position:0% +equals PI over 2 plane this is like an +annual angular momentum on the angular + + align:start position:0% +annual angular momentum on the angular + + + align:start position:0% +annual angular momentum on the angular +momentum parallel to the axis normal to + + align:start position:0% +momentum parallel to the axis normal to + + + align:start position:0% +momentum parallel to the axis normal to +that plane I'm going to call that the + + align:start position:0% +that plane I'm going to call that the + + + align:start position:0% +that plane I'm going to call that the +z-axis + + align:start position:0% +z-axis + + + align:start position:0% +z-axis +it's worth noting that all three of + + align:start position:0% +it's worth noting that all three of + + + align:start position:0% +it's worth noting that all three of +these things are also true for Rison or + + align:start position:0% +these things are also true for Rison or + + + align:start position:0% +these things are also true for Rison or +Nordstrom black holes this one is not + + align:start position:0% +Nordstrom black holes this one is not + + + align:start position:0% +Nordstrom black holes this one is not +true for ker but these two are ok so + + align:start position:0% +true for ker but these two are ok so + + + align:start position:0% +true for ker but these two are ok so +although the details change many of the + + align:start position:0% +although the details change many of the + + + align:start position:0% +although the details change many of the +concepts will carry over when you look + + align:start position:0% +concepts will carry over when you look + + + align:start position:0% +concepts will carry over when you look +at different more complicated classes of + + align:start position:0% +at different more complicated classes of + + + align:start position:0% +at different more complicated classes of +black holes let's now think about the + + align:start position:0% +black holes let's now think about the + + + align:start position:0% +black holes let's now think about the +four momentum of the body moving in a + + align:start position:0% +four momentum of the body moving in a + + + align:start position:0% +four momentum of the body moving in a +swirl of space-time + + align:start position:0% + + + + align:start position:0% + +so let's say it's got a rest mass M then + + align:start position:0% +so let's say it's got a rest mass M then + + + align:start position:0% +so let's say it's got a rest mass M then +it will have three components remember I + + align:start position:0% +it will have three components remember I + + + align:start position:0% +it will have three components remember I +have put this thing in a plane where + + align:start position:0% +have put this thing in a plane where + + + align:start position:0% +have put this thing in a plane where +there is no theta motion it'll have + + align:start position:0% +there is no theta motion it'll have + + + align:start position:0% +there is no theta motion it'll have +three fate emotions describing its + + align:start position:0% +three fate emotions describing its + + + align:start position:0% +three fate emotions describing its +motion with respect to the time + + align:start position:0% +motion with respect to the time + + + align:start position:0% +motion with respect to the time +coordinate the radial coordinate and the + + align:start position:0% +coordinate the radial coordinate and the + + + align:start position:0% +coordinate the radial coordinate and the +actual coordinate Phi okay so before I + + align:start position:0% +actual coordinate Phi okay so before I + + + align:start position:0% +actual coordinate Phi okay so before I +do anything with this let's take + + align:start position:0% +do anything with this let's take + + + align:start position:0% +do anything with this let's take +advantage of the fact that we have these + + align:start position:0% +advantage of the fact that we have these + + + align:start position:0% +advantage of the fact that we have these +quantities that are constants so using + + align:start position:0% +quantities that are constants so using + + + align:start position:0% +quantities that are constants so using +the fact that P downstairs mu is what I + + align:start position:0% +the fact that P downstairs mu is what I + + + align:start position:0% +the fact that P downstairs mu is what I +get when I hit this guy that should be a + + align:start position:0% +get when I hit this guy that should be a + + + align:start position:0% +get when I hit this guy that should be a +new me this is what I get when I hit + + align:start position:0% +new me this is what I get when I hit + + + align:start position:0% +new me this is what I get when I hit +this guy with the metric I can write out + + align:start position:0% +this guy with the metric I can write out + + + align:start position:0% +this guy with the metric I can write out +P sub T and P sub Phi + + align:start position:0% +P sub T and P sub Phi + + + align:start position:0% +P sub T and P sub Phi +let's do that on another board well + + align:start position:0% +let's do that on another board well + + + align:start position:0% +let's do that on another board well +let's do piece of tea first + + align:start position:0% +let's do piece of tea first + + + align:start position:0% +let's do piece of tea first +so P sub T is going to be G tt piece of + + align:start position:0% + + + + align:start position:0% + +okay this is - there's an M from that + + align:start position:0% +okay this is - there's an M from that + + + align:start position:0% +okay this is - there's an M from that +minus sign from my metric okay and this + + align:start position:0% +minus sign from my metric okay and this + + + align:start position:0% +minus sign from my metric okay and this +whole thing I define as the negative + + align:start position:0% +whole thing I define as the negative + + + align:start position:0% +whole thing I define as the negative +energy E okay so that combination okay + + align:start position:0% +energy E okay so that combination okay + + + align:start position:0% +energy E okay so that combination okay +we're gonna we'll do something at the + + align:start position:0% +we're gonna we'll do something at the + + + align:start position:0% +we're gonna we'll do something at the +rest mass in just a moment + + align:start position:0% +rest mass in just a moment + + + align:start position:0% +rest mass in just a moment +but you should basically say that as + + align:start position:0% +but you should basically say that as + + + align:start position:0% +but you should basically say that as +look at this is saying that DT D tau + + align:start position:0% +look at this is saying that DT D tau + + + align:start position:0% +look at this is saying that DT D tau +which tells me about how the body moves + + align:start position:0% +which tells me about how the body moves + + + align:start position:0% +which tells me about how the body moves +the respects to the Schwarzschild time + + align:start position:0% +the respects to the Schwarzschild time + + + align:start position:0% +the respects to the Schwarzschild time +coordinate that component of four + + align:start position:0% +coordinate that component of four + + + align:start position:0% +coordinate that component of four +velocity times 1 minus 2 GM over R is a + + align:start position:0% +velocity times 1 minus 2 GM over R is a + + + align:start position:0% +velocity times 1 minus 2 GM over R is a +constant let's look at P downstairs so + + align:start position:0% +constant let's look at P downstairs so + + + align:start position:0% +constant let's look at P downstairs so +this is M R squared sine squared theta + + align:start position:0% +this is M R squared sine squared theta + + + align:start position:0% +this is M R squared sine squared theta +ah we've chosen our orbital plane 1 + + align:start position:0% +ah we've chosen our orbital plane 1 + + + align:start position:0% +ah we've chosen our orbital plane 1 +times D Phi D tau this is equal to the + + align:start position:0% +times D Phi D tau this is equal to the + + + align:start position:0% +times D Phi D tau this is equal to the +angular mentum L sub Z in my notes I + + align:start position:0% +angular mentum L sub Z in my notes I + + + align:start position:0% +angular mentum L sub Z in my notes I +might flip around a little bit between L + + align:start position:0% +might flip around a little bit between L + + + align:start position:0% +might flip around a little bit between L +sub Z and L so let's massage these a + + align:start position:0% +sub Z and L so let's massage these a + + + align:start position:0% +sub Z and L so let's massage these a +little bit more so I can take these two + + align:start position:0% +little bit more so I can take these two + + + align:start position:0% +little bit more so I can take these two +expressions and I can use them to write + + align:start position:0% +expressions and I can use them to write + + + align:start position:0% +expressions and I can use them to write +DT D tau and D Phi D tau in terms of + + align:start position:0% +DT D tau and D Phi D tau in terms of + + + align:start position:0% +DT D tau and D Phi D tau in terms of +these conserved quantities so DT D tau + + align:start position:0% +these conserved quantities so DT D tau + + + align:start position:0% +these conserved quantities so DT D tau +is equal to I'm gonna call it e hat + + align:start position:0% +is equal to I'm gonna call it e hat + + + align:start position:0% +is equal to I'm gonna call it e hat +divided by 1 minus 2 GM over R + + align:start position:0% +divided by 1 minus 2 GM over R + + + align:start position:0% +divided by 1 minus 2 GM over R +if I D tau it's going to be L Z hat over + + align:start position:0% +if I D tau it's going to be L Z hat over + + + align:start position:0% +if I D tau it's going to be L Z hat over +R squared and so these quantities with a + + align:start position:0% +R squared and so these quantities with a + + + align:start position:0% +R squared and so these quantities with a +hat are just the conserved values + + align:start position:0% +hat are just the conserved values + + + align:start position:0% +hat are just the conserved values +normalized to the rest mass okay + + align:start position:0% +normalized to the rest mass okay + + + align:start position:0% +normalized to the rest mass okay +they all are proportional to rest mass + + align:start position:0% +they all are proportional to rest mass + + + align:start position:0% +they all are proportional to rest mass +but it's actually if you want to know + + align:start position:0% +but it's actually if you want to know + + + align:start position:0% +but it's actually if you want to know +what the this is essentially telling me + + align:start position:0% +what the this is essentially telling me + + + align:start position:0% +what the this is essentially telling me +about how clocks on the orbit tick + + align:start position:0% +about how clocks on the orbit tick + + + align:start position:0% +about how clocks on the orbit tick +relative to Talk clocks that are + + align:start position:0% +relative to Talk clocks that are + + + align:start position:0% +relative to Talk clocks that are +infinitely far away and that can't + + align:start position:0% +infinitely far away and that can't + + + align:start position:0% +infinitely far away and that can't +depend on the mass of the orbiting + + align:start position:0% +depend on the mass of the orbiting + + + align:start position:0% +depend on the mass of the orbiting +object this is telling me about how this + + align:start position:0% +object this is telling me about how this + + + align:start position:0% +object this is telling me about how this +small body is moving according to the + + align:start position:0% +small body is moving according to the + + + align:start position:0% +small body is moving according to the +clock of the orbiting observer and again + + align:start position:0% +clock of the orbiting observer and again + + + align:start position:0% +clock of the orbiting observer and again +that can't depend on the mass of the + + align:start position:0% +that can't depend on the mass of the + + + align:start position:0% +that can't depend on the mass of the +object okay + + align:start position:0% +object okay + + + align:start position:0% +object okay +so that's kind of cool so I've now + + align:start position:0% +so that's kind of cool so I've now + + + align:start position:0% +so that's kind of cool so I've now +managed to relate three to be two of the + + align:start position:0% +managed to relate three to be two of the + + + align:start position:0% +managed to relate three to be two of the +three components of the four momentum + + align:start position:0% +three components of the four momentum + + + align:start position:0% +three components of the four momentum +two functions of our and quantities that + + align:start position:0% +two functions of our and quantities that + + + align:start position:0% +two functions of our and quantities that +are known to be constant that's good + + align:start position:0% +are known to be constant that's good + + + align:start position:0% +are known to be constant that's good +we have one more overall constraint we + + align:start position:0% +we have one more overall constraint we + + + align:start position:0% +we have one more overall constraint we +know that if I take P dot P I get + + align:start position:0% +know that if I take P dot P I get + + + align:start position:0% +know that if I take P dot P I get +negative of the rest mass squared so + + align:start position:0% +negative of the rest mass squared so + + + align:start position:0% +negative of the rest mass squared so +this + + align:start position:0% + + + + align:start position:0% + +okay notice every single term is + + align:start position:0% +okay notice every single term is + + + align:start position:0% +okay notice every single term is +proportional to M Squared so I can + + align:start position:0% +proportional to M Squared so I can + + + align:start position:0% +proportional to M Squared so I can +divide that out I can insert DT D tau I + + align:start position:0% +divide that out I can insert DT D tau I + + + align:start position:0% +divide that out I can insert DT D tau I +can replace for this e divided by this + + align:start position:0% +can replace for this e divided by this + + + align:start position:0% +can replace for this e divided by this +guy I can replace D Phi D tau by my LZ + + align:start position:0% +guy I can replace D Phi D tau by my LZ + + + align:start position:0% +guy I can replace D Phi D tau by my LZ +hat divided by R squared doing so + + align:start position:0% + + + + align:start position:0% + +manipulating a little bit I get + + align:start position:0% + + + + align:start position:0% + +get something like this and let me + + align:start position:0% +get something like this and let me + + + align:start position:0% +get something like this and let me +rearrange this a tiny bit + + align:start position:0% + + + + align:start position:0% + +alright I have managed to reduce this to + + align:start position:0% +alright I have managed to reduce this to + + + align:start position:0% +alright I have managed to reduce this to +a one-dimensional problem okay so going + + align:start position:0% +a one-dimensional problem okay so going + + + align:start position:0% +a one-dimensional problem okay so going +from that line over there basically all + + align:start position:0% +from that line over there basically all + + + align:start position:0% +from that line over there basically all +I did was insert the relationship + + align:start position:0% +I did was insert the relationship + + + align:start position:0% +I did was insert the relationship +between DT D TV talent II the Phoebe + + align:start position:0% +between DT D TV talent II the Phoebe + + + align:start position:0% +between DT D TV talent II the Phoebe +towel and L cleared out some overall + + align:start position:0% +towel and L cleared out some overall + + + align:start position:0% +towel and L cleared out some overall +factors of things like 1 minus 2 GM over + + align:start position:0% +factors of things like 1 minus 2 GM over + + + align:start position:0% +factors of things like 1 minus 2 GM over +R manipulate manipulate manipulate and + + align:start position:0% +R manipulate manipulate manipulate and + + + align:start position:0% +R manipulate manipulate manipulate and +what you finally get is this lovely + + align:start position:0% +what you finally get is this lovely + + + align:start position:0% +what you finally get is this lovely +equation here that tells you how the + + align:start position:0% +equation here that tells you how the + + + align:start position:0% +equation here that tells you how the +radial velocity the radial velocity + + align:start position:0% +radial velocity the radial velocity + + + align:start position:0% +radial velocity the radial velocity +respect to proper time how it depends as + + align:start position:0% +respect to proper time how it depends as + + + align:start position:0% +respect to proper time how it depends as +a function of R given the energy and the + + align:start position:0% +a function of R given the energy and the + + + align:start position:0% +a function of R given the energy and the +angular momentum I have written it in + + align:start position:0% +angular momentum I have written it in + + + align:start position:0% +angular momentum I have written it in +this form because the problem is very + + align:start position:0% +this form because the problem is very + + + align:start position:0% +this form because the problem is very +strikingly reminiscent to the Newtonian + + align:start position:0% +strikingly reminiscent to the Newtonian + + + align:start position:0% +strikingly reminiscent to the Newtonian +problem of understanding the motion of a + + align:start position:0% +problem of understanding the motion of a + + + align:start position:0% +problem of understanding the motion of a +particle in a 1 over R potential which + + align:start position:0% +particle in a 1 over R potential which + + + align:start position:0% +particle in a 1 over R potential which +we often described as having an + + align:start position:0% +we often described as having an + + + align:start position:0% +we often described as having an +effective potential that has a + + align:start position:0% +effective potential that has a + + + align:start position:0% +effective potential that has a +gravitational term Newton's gravity or + + align:start position:0% +gravitational term Newton's gravity or + + + align:start position:0% +gravitational term Newton's gravity or +if you're doing things like quantum + + align:start position:0% +if you're doing things like quantum + + + align:start position:0% +if you're doing things like quantum +mechanics the Coulomb potential and a + + align:start position:0% +mechanics the Coulomb potential and a + + + align:start position:0% +mechanics the Coulomb potential and a +Coulomb barrier associated with the + + align:start position:0% +Coulomb barrier associated with the + + + align:start position:0% +Coulomb barrier associated with the +angular momentum of an orbit so one way + + align:start position:0% +angular momentum of an orbit so one way + + + align:start position:0% +angular momentum of an orbit so one way +to approach what we've got now ok one + + align:start position:0% +to approach what we've got now ok one + + + align:start position:0% +to approach what we've got now ok one +thing that we could do is essentially + + align:start position:0% +thing that we could do is essentially + + + align:start position:0% +thing that we could do is essentially +just pick your energy and your LZ pick + + align:start position:0% +just pick your energy and your LZ pick + + + align:start position:0% +just pick your energy and your LZ pick +your energy in your angular momentum + + align:start position:0% +your energy in your angular momentum + + + align:start position:0% +your energy in your angular momentum +pick an initial position + + align:start position:0% + + + + align:start position:0% + +imagine you synchronize the clocks at T + + align:start position:0% +imagine you synchronize the clocks at T + + + align:start position:0% +imagine you synchronize the clocks at T +equals zero and then just integrate + + align:start position:0% + + + + align:start position:0% + +you've got your DRD tau given here don't + + align:start position:0% +you've got your DRD tau given here don't + + + align:start position:0% +you've got your DRD tau given here don't +forget you also have D Phi D tau and DT + + align:start position:0% +forget you also have D Phi D tau and DT + + + align:start position:0% +forget you also have D Phi D tau and DT +D tau related to the energy and like so + + align:start position:0% +D tau related to the energy and like so + + + align:start position:0% +D tau related to the energy and like so +boom to closed system you can always do + + align:start position:0% +boom to closed system you can always do + + + align:start position:0% +boom to closed system you can always do +just sort of a little numerical + + align:start position:0% +just sort of a little numerical + + + align:start position:0% +just sort of a little numerical +integration of this in a certain sense + + align:start position:0% +integration of this in a certain sense + + + align:start position:0% +integration of this in a certain sense +this completely specifies the problem + + align:start position:0% +this completely specifies the problem + + + align:start position:0% +this completely specifies the problem +there's so much more we can do in + + align:start position:0% +there's so much more we can do in + + + align:start position:0% +there's so much more we can do in +particular what we see is that all of + + align:start position:0% +particular what we see is that all of + + + align:start position:0% +particular what we see is that all of +the interesting behavior associate with + + align:start position:0% +the interesting behavior associate with + + + align:start position:0% +the interesting behavior associate with +this orbit is bound up in this function + + align:start position:0% +this orbit is bound up in this function + + + align:start position:0% +this orbit is bound up in this function +V effective so something that's really + + align:start position:0% +V effective so something that's really + + + align:start position:0% +V effective so something that's really +useful for us to do is to take a look at + + align:start position:0% +useful for us to do is to take a look at + + + align:start position:0% +useful for us to do is to take a look at +what this V effective looks like okay so + + align:start position:0% +what this V effective looks like okay so + + + align:start position:0% +what this V effective looks like okay so +suppose you are given a particular value + + align:start position:0% +suppose you are given a particular value + + + align:start position:0% +suppose you are given a particular value +for e hat and LZ hat and you plot V + + align:start position:0% +for e hat and LZ hat and you plot V + + + align:start position:0% +for e hat and LZ hat and you plot V +effective versus R + + align:start position:0% + + + + align:start position:0% + +well what you typically find is that + + align:start position:0% +well what you typically find is that + + + align:start position:0% +well what you typically find is that +it's got a behavior that looks kind of + + align:start position:0% +it's got a behavior that looks kind of + + + align:start position:0% +it's got a behavior that looks kind of +like this where this value right here is + + align:start position:0% + + + + align:start position:0% + +the effect of equal to one okay notice + + align:start position:0% +the effect of equal to one okay notice + + + align:start position:0% +the effect of equal to one okay notice +as R goes to infinity you get 1 times 1 + + align:start position:0% +as R goes to infinity you get 1 times 1 + + + align:start position:0% +as R goes to infinity you get 1 times 1 +so this asymptotes to 1 notice a hat + + align:start position:0% +so this asymptotes to 1 notice a hat + + + align:start position:0% +so this asymptotes to 1 notice a hat +squared has the same dimensions as V + + align:start position:0% +squared has the same dimensions as V + + + align:start position:0% +squared has the same dimensions as V +effective in fact in the unit choices + + align:start position:0% +effective in fact in the unit choices + + + align:start position:0% +effective in fact in the unit choices +I've used here they are both + + align:start position:0% +I've used here they are both + + + align:start position:0% +I've used here they are both +dimensionless so what we can do is plot + + align:start position:0% +dimensionless so what we can do is plot + + + align:start position:0% +dimensionless so what we can do is plot +let's imagine that we have what I'm + + align:start position:0% +let's imagine that we have what I'm + + + align:start position:0% +let's imagine that we have what I'm +gonna want to sketch this on a different + + align:start position:0% +gonna want to sketch this on a different + + + align:start position:0% +gonna want to sketch this on a different +board let me go over here so I'm gonna + + align:start position:0% +board let me go over here so I'm gonna + + + align:start position:0% +board let me go over here so I'm gonna +want to look at a couple of different + + align:start position:0% +want to look at a couple of different + + + align:start position:0% +want to look at a couple of different +values of the effective give me a couple + + align:start position:0% +values of the effective give me a couple + + + align:start position:0% +values of the effective give me a couple +of different values of e hat + + align:start position:0% + + + + align:start position:0% + +okay so here's an example this guy's + + align:start position:0% +okay so here's an example this guy's + + + align:start position:0% +okay so here's an example this guy's +putting up one so since he hat as I said + + align:start position:0% +putting up one so since he hat as I said + + + align:start position:0% +putting up one so since he hat as I said +has the same units as V effective let's + + align:start position:0% +has the same units as V effective let's + + + align:start position:0% +has the same units as V effective let's +plot them together so example one + + align:start position:0% +plot them together so example one + + + align:start position:0% +plot them together so example one +imagine if Yi hat lies right here okay + + align:start position:0% +imagine if Yi hat lies right here okay + + + align:start position:0% +imagine if Yi hat lies right here okay +let's call this P Hat 1 so this is some + + align:start position:0% +let's call this P Hat 1 so this is some + + + align:start position:0% +let's call this P Hat 1 so this is some +value that is greater than one what is + + align:start position:0% +value that is greater than one what is + + + align:start position:0% +value that is greater than one what is +the point of doing this well notice I'm + + align:start position:0% +the point of doing this well notice I'm + + + align:start position:0% +the point of doing this well notice I'm +gonna flip back and forth between these + + align:start position:0% +gonna flip back and forth between these + + + align:start position:0% +gonna flip back and forth between these +two middle boards here let's look at the + + align:start position:0% +two middle boards here let's look at the + + + align:start position:0% +two middle boards here let's look at the +equation that governs the radial motion + + align:start position:0% +equation that governs the radial motion + + + align:start position:0% +equation that governs the radial motion +of this body + + align:start position:0% + + + + align:start position:0% + +DRD Tao has to be a real number this has + + align:start position:0% +DRD Tao has to be a real number this has + + + align:start position:0% +DRD Tao has to be a real number this has +to be a real number so we have to have a + + align:start position:0% +to be a real number so we have to have a + + + align:start position:0% +to be a real number so we have to have a +hat squared greater than or equal to V + + align:start position:0% +hat squared greater than or equal to V + + + align:start position:0% +hat squared greater than or equal to V +effective in order for dr D tau to have + + align:start position:0% +effective in order for dr D tau to have + + + align:start position:0% +effective in order for dr D tau to have +a meaningful solution so let's look at + + align:start position:0% +a meaningful solution so let's look at + + + align:start position:0% +a meaningful solution so let's look at +my example here we have one t hat one is + + align:start position:0% +my example here we have one t hat one is + + + align:start position:0% +my example here we have one t hat one is +greater than my effective potential + + align:start position:0% +greater than my effective potential + + + align:start position:0% +greater than my effective potential +everywhere at all radii until I get down + + align:start position:0% +everywhere at all radii until I get down + + + align:start position:0% +everywhere at all radii until I get down +to here it's called that r1 so in this + + align:start position:0% +to here it's called that r1 so in this + + + align:start position:0% +to here it's called that r1 so in this +case DRD tell if I think about this + + align:start position:0% +case DRD tell if I think about this + + + align:start position:0% +case DRD tell if I think about this +thing so note that's a finds DRD tau + + align:start position:0% +thing so note that's a finds DRD tau + + + align:start position:0% +thing so note that's a finds DRD tau +squared right let's suppose we take the + + align:start position:0% +squared right let's suppose we take the + + + align:start position:0% +squared right let's suppose we take the +negative square root + + align:start position:0% +negative square root + + + align:start position:0% +negative square root +the our D tau is positive and inward + + align:start position:0% +the our D tau is positive and inward + + + align:start position:0% +the our D tau is positive and inward +it's negative negative and real negative + + align:start position:0% +it's negative negative and real negative + + + align:start position:0% +it's negative negative and real negative +and real negative and real negative and + + align:start position:0% +and real negative and real negative and + + + align:start position:0% +and real negative and real negative and +real negative in real boom it's zero can + + align:start position:0% +real negative in real boom it's zero can + + + align:start position:0% +real negative in real boom it's zero can +it go into here nu cannot go into there + + align:start position:0% +it go into here nu cannot go into there + + + align:start position:0% +it go into here nu cannot go into there +because their a hat squared is less + + align:start position:0% + + + + align:start position:0% + +sorry human squared inside here a hat + + align:start position:0% +sorry human squared inside here a hat + + + align:start position:0% +sorry human squared inside here a hat +squared is less than the effect of + + align:start position:0% +squared is less than the effect of + + + align:start position:0% +squared is less than the effect of +potential DRD tau is imaginary that + + align:start position:0% +potential DRD tau is imaginary that + + + align:start position:0% +potential DRD tau is imaginary that +doesn't make any sense the only option + + align:start position:0% +doesn't make any sense the only option + + + align:start position:0% +doesn't make any sense the only option +is for this guy to change sign and + + align:start position:0% +is for this guy to change sign and + + + align:start position:0% +is for this guy to change sign and +trundle right back out so e hat greater + + align:start position:0% +trundle right back out so e hat greater + + + align:start position:0% +trundle right back out so e hat greater +than one corresponds to a body that + + align:start position:0% +than one corresponds to a body that + + + align:start position:0% +than one corresponds to a body that +comes in + + align:start position:0% + + + + align:start position:0% + +from large radius turns around at the + + align:start position:0% +from large radius turns around at the + + + align:start position:0% +from large radius turns around at the +particular radius where he hat is the + + align:start position:0% +particular radius where he hat is the + + + align:start position:0% +particular radius where he hat is the +square root of the effect potential and + + align:start position:0% +square root of the effect potential and + + + align:start position:0% +square root of the effect potential and +then goes back out to infinity or back + + align:start position:0% +then goes back out to infinity or back + + + align:start position:0% +then goes back out to infinity or back +out to let's not say infinity goes back + + align:start position:0% +out to let's not say infinity goes back + + + align:start position:0% +out to let's not say infinity goes back +out to large radius okay + + align:start position:0% +out to large radius okay + + + align:start position:0% +out to large radius okay +in Newtonian gravity we would call this + + align:start position:0% +in Newtonian gravity we would call this + + + align:start position:0% +in Newtonian gravity we would call this +a hyperbolic orbit okay this corresponds + + align:start position:0% +a hyperbolic orbit okay this corresponds + + + align:start position:0% +a hyperbolic orbit okay this corresponds +to so remember when I did this I have + + align:start position:0% +to so remember when I did this I have + + + align:start position:0% +to so remember when I did this I have +not I'm not actually I'm only computing + + align:start position:0% +not I'm not actually I'm only computing + + + align:start position:0% +not I'm not actually I'm only computing +the radial motion I'm not looking at the + + align:start position:0% +the radial motion I'm not looking at the + + + align:start position:0% +the radial motion I'm not looking at the +fine motion so this actually when you + + align:start position:0% +fine motion so this actually when you + + + align:start position:0% +fine motion so this actually when you +when you look at both the radial motion + + align:start position:0% +when you look at both the radial motion + + + align:start position:0% +when you look at both the radial motion +in the Phi motion what you see is that + + align:start position:0% +in the Phi motion what you see is that + + + align:start position:0% +in the Phi motion what you see is that +this is a body that comes in and then + + align:start position:0% +this is a body that comes in and then + + + align:start position:0% +this is a body that comes in and then +sort of whips around that small radius + + align:start position:0% +sort of whips around that small radius + + + align:start position:0% +sort of whips around that small radius +and goes right back out let's look at + + align:start position:0% +and goes right back out let's look at + + + align:start position:0% +and goes right back out let's look at +example another example let's call this + + align:start position:0% +example another example let's call this + + + align:start position:0% +example another example let's call this +e to some value that is less than 1 okay + + align:start position:0% +e to some value that is less than 1 okay + + + align:start position:0% +e to some value that is less than 1 okay +well for a hat - it's a potential + + align:start position:0% + + + + align:start position:0% + +potential is underneath he had to + + align:start position:0% +potential is underneath he had to + + + align:start position:0% +potential is underneath he had to +squared only between these two radii + + align:start position:0% +squared only between these two radii + + + align:start position:0% +squared only between these two radii +which I will call R sub P in R sub a + + align:start position:0% + + + + align:start position:0% + +what we expect in this case is motion of + + align:start position:0% +what we expect in this case is motion of + + + align:start position:0% +what we expect in this case is motion of +this body essentially going back and + + align:start position:0% +this body essentially going back and + + + align:start position:0% +this body essentially going back and +forth and turning around at periastron + + align:start position:0% +forth and turning around at periastron + + + align:start position:0% +forth and turning around at periastron +and appo astron this is a relativistic + + align:start position:0% +and appo astron this is a relativistic + + + align:start position:0% +and appo astron this is a relativistic +generation relativistic generalization + + align:start position:0% +generation relativistic generalization + + + align:start position:0% +generation relativistic generalization +of an elliptical orbit okay in general + + align:start position:0% +of an elliptical orbit okay in general + + + align:start position:0% +of an elliptical orbit okay in general +activity they turn out generally not to + + align:start position:0% +activity they turn out generally not to + + + align:start position:0% +activity they turn out generally not to +be ellipses so we call this an eccentric + + align:start position:0% +be ellipses so we call this an eccentric + + + align:start position:0% +be ellipses so we call this an eccentric +orbit in the weak field limit if you + + align:start position:0% +orbit in the weak field limit if you + + + align:start position:0% +orbit in the weak field limit if you +imagine are being very very large it's + + align:start position:0% +imagine are being very very large it's + + + align:start position:0% +imagine are being very very large it's +not hard to show that the motion is + + align:start position:0% +not hard to show that the motion is + + + align:start position:0% +not hard to show that the motion is +nearly an ellipse but it's an ellipse + + align:start position:0% +nearly an ellipse but it's an ellipse + + + align:start position:0% +nearly an ellipse but it's an ellipse +whose long axis is slowly processing + + align:start position:0% +whose long axis is slowly processing + + + align:start position:0% +whose long axis is slowly processing +this actually leads to the famous + + align:start position:0% +this actually leads to the famous + + + align:start position:0% +this actually leads to the famous +perihelion precession of mercury that + + align:start position:0% +perihelion precession of mercury that + + + align:start position:0% +perihelion precession of mercury that +Einstein first calculated and this is an + + align:start position:0% +Einstein first calculated and this is an + + + align:start position:0% +Einstein first calculated and this is an +exercise that I am asking you to do on + + align:start position:0% +exercise that I am asking you to do on + + + align:start position:0% +exercise that I am asking you to do on +one of the final piece sets of this + + align:start position:0% +one of the final piece sets of this + + + align:start position:0% +one of the final piece sets of this +course using what I have set up here + + align:start position:0% +course using what I have set up here + + + align:start position:0% +course using what I have set up here +it's really not that difficult to do let + + align:start position:0% +it's really not that difficult to do let + + + align:start position:0% +it's really not that difficult to do let +me go to another board and note that one + + align:start position:0% +me go to another board and note that one + + + align:start position:0% +me go to another board and note that one +could imagine in energy such that the Rd + + align:start position:0% +could imagine in energy such that the Rd + + + align:start position:0% +could imagine in energy such that the Rd +tau is exactly zero + + align:start position:0% + + + + align:start position:0% + +so if you choose your energy so that you + + align:start position:0% +so if you choose your energy so that you + + + align:start position:0% +so if you choose your energy so that you +sit right here at the minimum of the + + align:start position:0% +sit right here at the minimum of the + + + align:start position:0% +sit right here at the minimum of the +potential I will label this as point s + + align:start position:0% + + + + align:start position:0% + +the energy that corresponds to exactly + + align:start position:0% +the energy that corresponds to exactly + + + align:start position:0% +the energy that corresponds to exactly +that point is what would be a that is + + align:start position:0% +that point is what would be a that is + + + align:start position:0% +that point is what would be a that is +there is a single point at which DRD tau + + align:start position:0% +there is a single point at which DRD tau + + + align:start position:0% +there is a single point at which DRD tau +equals zero anywhere away from that dr + + align:start position:0% +equals zero anywhere away from that dr + + + align:start position:0% +equals zero anywhere away from that dr +detail would be imaginary so that's not + + align:start position:0% +detail would be imaginary so that's not + + + align:start position:0% +detail would be imaginary so that's not +going to work + + align:start position:0% +going to work + + + align:start position:0% +going to work +but right at that point dr d tau equals + + align:start position:0% +but right at that point dr d tau equals + + + align:start position:0% +but right at that point dr d tau equals +zero and you get a circular orbit notice + + align:start position:0% +zero and you get a circular orbit notice + + + align:start position:0% +zero and you get a circular orbit notice +there's a second point in which that can + + align:start position:0% +there's a second point in which that can + + + align:start position:0% +there's a second point in which that can +happen let's call this point u perhaps + + align:start position:0% +happen let's call this point u perhaps + + + align:start position:0% +happen let's call this point u perhaps +you can guess why i called these points + + align:start position:0% +you can guess why i called these points + + + align:start position:0% +you can guess why i called these points +s and u if you imagine that you know you + + align:start position:0% +s and u if you imagine that you know you + + + align:start position:0% +s and u if you imagine that you know you +add a tiny amount of energy right here + + align:start position:0% +add a tiny amount of energy right here + + + align:start position:0% +add a tiny amount of energy right here +well it'll do is they'll execute small + + align:start position:0% +well it'll do is they'll execute small + + + align:start position:0% +well it'll do is they'll execute small +oscillations around the point s it'll + + align:start position:0% +oscillations around the point s it'll + + + align:start position:0% +oscillations around the point s it'll +sort of move it up to something that's + + align:start position:0% +sort of move it up to something that's + + + align:start position:0% +sort of move it up to something that's +similar to what I drew up there as e to + + align:start position:0% +similar to what I drew up there as e to + + + align:start position:0% +similar to what I drew up there as e to +but was a very small eccentricity so if + + align:start position:0% +but was a very small eccentricity so if + + + align:start position:0% +but was a very small eccentricity so if +I slightly disturb a circular orbit down + + align:start position:0% +I slightly disturb a circular orbit down + + + align:start position:0% +I slightly disturb a circular orbit down +here at s I essentially just oscillate + + align:start position:0% +here at s I essentially just oscillate + + + align:start position:0% +here at s I essentially just oscillate +in the vicinity of that circular orbit S + + align:start position:0% +in the vicinity of that circular orbit S + + + align:start position:0% +in the vicinity of that circular orbit S +stands for stable if I have an orbit up + + align:start position:0% +stands for stable if I have an orbit up + + + align:start position:0% +stands for stable if I have an orbit up +here at U and I very slightly perturb it + + align:start position:0% +here at U and I very slightly perturb it + + + align:start position:0% +here at U and I very slightly perturb it +well it'll either go in and eventually + + align:start position:0% +well it'll either go in and eventually + + + align:start position:0% +well it'll either go in and eventually +reach R equals 0 or it'll go out and + + align:start position:0% +reach R equals 0 or it'll go out and + + + align:start position:0% +reach R equals 0 or it'll go out and +then it's completely unbound and they'll + + align:start position:0% +then it's completely unbound and they'll + + + align:start position:0% +then it's completely unbound and they'll +just keep trundling all the way out + + align:start position:0% +just keep trundling all the way out + + + align:start position:0% +just keep trundling all the way out +essentially forever + + align:start position:0% +essentially forever + + + align:start position:0% +essentially forever +this guy is unstable stable orbits are + + align:start position:0% +this guy is unstable stable orbits are + + + align:start position:0% +this guy is unstable stable orbits are +particularly interesting and important + + align:start position:0% +particularly interesting and important + + + align:start position:0% +particularly interesting and important +so let's look at these look at these + + align:start position:0% +so let's look at these look at these + + + align:start position:0% +so let's look at these look at these +orbits and a little bit more care + + align:start position:0% + + + + align:start position:0% + +so the very definition of a circular + + align:start position:0% +so the very definition of a circular + + + align:start position:0% +so the very definition of a circular +orbit is that DRD tau equal to zero its + + align:start position:0% +orbit is that DRD tau equal to zero its + + + align:start position:0% +orbit is that DRD tau equal to zero its +radius does not change if DRD tau equals + + align:start position:0% +radius does not change if DRD tau equals + + + align:start position:0% +radius does not change if DRD tau equals +zero then it must have a hat equal the + + align:start position:0% +zero then it must have a hat equal the + + + align:start position:0% +zero then it must have a hat equal the +square root of the effective okay + + align:start position:0% +square root of the effective okay + + + align:start position:0% +square root of the effective okay +both of these orbits happen to live at + + align:start position:0% +both of these orbits happen to live at + + + align:start position:0% +both of these orbits happen to live at +either a minimum or a maximum of this + + align:start position:0% +either a minimum or a maximum of this + + + align:start position:0% +either a minimum or a maximum of this +potential curve so I'm going to require + + align:start position:0% + + + + align:start position:0% + +that the partial derivative of that + + align:start position:0% +that the partial derivative of that + + + align:start position:0% +that the partial derivative of that +potential with respect to R be equal to + + align:start position:0% +potential with respect to R be equal to + + + align:start position:0% +potential with respect to R be equal to +zero so let's take a look at this + + align:start position:0% +zero so let's take a look at this + + + align:start position:0% +zero so let's take a look at this +condition my effective potential is + + align:start position:0% +condition my effective potential is + + + align:start position:0% +condition my effective potential is +given up here do a little bit of algebra + + align:start position:0% +given up here do a little bit of algebra + + + align:start position:0% +given up here do a little bit of algebra +with this set this guy equal to zero + + align:start position:0% +with this set this guy equal to zero + + + align:start position:0% +with this set this guy equal to zero +what you'll find after your algebraic + + align:start position:0% +what you'll find after your algebraic + + + align:start position:0% +what you'll find after your algebraic +smoke clears is that you get this + + align:start position:0% +smoke clears is that you get this + + + align:start position:0% +smoke clears is that you get this +condition on the angular momentum + + align:start position:0% + + + + align:start position:0% + +notice as our gets really large oh shoot + + align:start position:0% + + + + align:start position:0% + +try that again + + align:start position:0% +try that again + + + align:start position:0% +try that again +notice as R gets really large that this + + align:start position:0% +notice as R gets really large that this + + + align:start position:0% +notice as R gets really large that this +asymptotes to plus or minus the square + + align:start position:0% +asymptotes to plus or minus the square + + + align:start position:0% +asymptotes to plus or minus the square +root of GM R that is indeed exactly what + + align:start position:0% +root of GM R that is indeed exactly what + + + align:start position:0% +root of GM R that is indeed exactly what +you get for the angular momentum of a + + align:start position:0% +you get for the angular momentum of a + + + align:start position:0% +you get for the angular momentum of a +circular Newtonian orbit okay so it's a + + align:start position:0% +circular Newtonian orbit okay so it's a + + + align:start position:0% +circular Newtonian orbit okay so it's a +nice sanity check it appears to be + + align:start position:0% +nice sanity check it appears to be + + + align:start position:0% +nice sanity check it appears to be +somewhat pathological and as R + + align:start position:0% +somewhat pathological and as R + + + align:start position:0% +somewhat pathological and as R +approaches 3 GM though hold that thought + + align:start position:0% + + + + align:start position:0% + +okay so now let's take that value of L + + align:start position:0% +okay so now let's take that value of L + + + align:start position:0% +okay so now let's take that value of L +plug it back into the potential and set + + align:start position:0% +plug it back into the potential and set + + + align:start position:0% +plug it back into the potential and set +e equal to the square root of that okay + + align:start position:0% +e equal to the square root of that okay + + + align:start position:0% +e equal to the square root of that okay +a little bit of algebra ensues and what + + align:start position:0% +a little bit of algebra ensues and what + + + align:start position:0% +a little bit of algebra ensues and what +you find set this equals 1 minus 2 GM + + align:start position:0% +you find set this equals 1 minus 2 GM + + + align:start position:0% +you find set this equals 1 minus 2 GM +over R over again that factor under a + + align:start position:0% +over R over again that factor under a + + + align:start position:0% +over R over again that factor under a +square root of 1 minus 3 GM over R again + + align:start position:0% +square root of 1 minus 3 GM over R again + + + align:start position:0% +square root of 1 minus 3 GM over R again +we sort of see something a little bit + + align:start position:0% +we sort of see something a little bit + + + align:start position:0% +we sort of see something a little bit +pathological happening as R goes to 3 GM + + align:start position:0% +pathological happening as R goes to 3 GM + + + align:start position:0% +pathological happening as R goes to 3 GM +let me make two comments about this so + + align:start position:0% +let me make two comments about this so + + + align:start position:0% +let me make two comments about this so +first of all notice that this energy it + + align:start position:0% +first of all notice that this energy it + + + align:start position:0% +first of all notice that this energy it +is smaller than what I can intuitively + + align:start position:0% + + + + align:start position:0% + +you can sort of imagine remember a hat + + align:start position:0% +you can sort of imagine remember a hat + + + align:start position:0% +you can sort of imagine remember a hat +is the energy per unit rest mass you can + + align:start position:0% +is the energy per unit rest mass you can + + + align:start position:0% +is the energy per unit rest mass you can +think of this as something like total + + align:start position:0% +think of this as something like total + + + align:start position:0% +think of this as something like total +energy over m so the or energy associate + + align:start position:0% +energy over m so the or energy associate + + + align:start position:0% +energy over m so the or energy associate +the orbiting body it's got a rest energy + + align:start position:0% +the orbiting body it's got a rest energy + + + align:start position:0% +the orbiting body it's got a rest energy +a kinetic energy and a potential energy + + align:start position:0% + + + + align:start position:0% + +divided by M swarn orbit to be bound + + align:start position:0% +divided by M swarn orbit to be bound + + + align:start position:0% +divided by M swarn orbit to be bound +it's a potential energy which is- must + + align:start position:0% +it's a potential energy which is- must + + + align:start position:0% +it's a potential energy which is- must +have larger magnitude than the kinetic + + align:start position:0% +have larger magnitude than the kinetic + + + align:start position:0% +have larger magnitude than the kinetic +energy okay so for a bound orbit a + + align:start position:0% +energy okay so for a bound orbit a + + + align:start position:0% +energy okay so for a bound orbit a +kinetic plus potential will be a + + align:start position:0% +kinetic plus potential will be a + + + align:start position:0% +kinetic plus potential will be a +negative quantity so the numerator is + + align:start position:0% +negative quantity so the numerator is + + + align:start position:0% +negative quantity so the numerator is +going to be something that when + + align:start position:0% +going to be something that when + + + align:start position:0% +going to be something that when +normalized to M is less than 1 so this + + align:start position:0% +normalized to M is less than 1 so this + + + align:start position:0% +normalized to M is less than 1 so this +is exactly what we expect student or + + align:start position:0% +is exactly what we expect student or + + + align:start position:0% +is exactly what we expect student or +'but notice also so if you take this + + align:start position:0% +'but notice also so if you take this + + + align:start position:0% +'but notice also so if you take this +formula and look at + + align:start position:0% +formula and look at + + + align:start position:0% +formula and look at +and the large our limit it goes to 1 + + align:start position:0% +and the large our limit it goes to 1 + + + align:start position:0% +and the large our limit it goes to 1 +minus GM over 2r this is in fact exactly + + align:start position:0% +minus GM over 2r this is in fact exactly + + + align:start position:0% +minus GM over 2r this is in fact exactly +what you get when you look at the energy + + align:start position:0% +what you get when you look at the energy + + + align:start position:0% +what you get when you look at the energy +per unit mass throwing in you know just + + align:start position:0% +per unit mass throwing in you know just + + + align:start position:0% +per unit mass throwing in you know just +sort of by hand a rest mass the minus GM + + align:start position:0% +sort of by hand a rest mass the minus GM + + + align:start position:0% +sort of by hand a rest mass the minus GM +over 2r exactly corresponds to kinetic + + align:start position:0% +over 2r exactly corresponds to kinetic + + + align:start position:0% +over 2r exactly corresponds to kinetic +plus potential for a Newtonian circular + + align:start position:0% +plus potential for a Newtonian circular + + + align:start position:0% +plus potential for a Newtonian circular +orbit so lots of stuff is hanging + + align:start position:0% +orbit so lots of stuff is hanging + + + align:start position:0% +orbit so lots of stuff is hanging +together nicely so we've just learned + + align:start position:0% +together nicely so we've just learned + + + align:start position:0% +together nicely so we've just learned +that we can characterize the energy and + + align:start position:0% +that we can characterize the energy and + + + align:start position:0% +that we can characterize the energy and +annual angular momentum of circular + + align:start position:0% +annual angular momentum of circular + + + align:start position:0% +annual angular momentum of circular +orbits around my black hole let's look + + align:start position:0% +orbits around my black hole let's look + + + align:start position:0% +orbits around my black hole let's look +at a couple other things associated this + + align:start position:0% +at a couple other things associated this + + + align:start position:0% +at a couple other things associated this +so these plots where I look at the + + align:start position:0% +so these plots where I look at the + + + align:start position:0% +so these plots where I look at the +radial motion in this effective + + align:start position:0% +radial motion in this effective + + + align:start position:0% +radial motion in this effective +potential as I mentioned a few moments + + align:start position:0% +potential as I mentioned a few moments + + + align:start position:0% +potential as I mentioned a few moments +ago there's additional sort of degrees + + align:start position:0% +ago there's additional sort of degrees + + + align:start position:0% +ago there's additional sort of degrees +of freedom in the motion that are being + + align:start position:0% +of freedom in the motion that are being + + + align:start position:0% +of freedom in the motion that are being +suppressed here right so this thing is + + align:start position:0% +suppressed here right so this thing is + + + align:start position:0% +suppressed here right so this thing is +also moving in in that plane it's + + align:start position:0% +also moving in in that plane it's + + + align:start position:0% +also moving in in that plane it's +whirling around with respect to Phi + + align:start position:0% +whirling around with respect to Phi + + + align:start position:0% +whirling around with respect to Phi +we've lost that information in the way + + align:start position:0% +we've lost that information in the way + + + align:start position:0% +we've lost that information in the way +we've drawn this here let's define Omega + + align:start position:0% +we've drawn this here let's define Omega + + + align:start position:0% +we've drawn this here let's define Omega +to be the angular velocity of this orbit + + align:start position:0% +to be the angular velocity of this orbit + + + align:start position:0% +to be the angular velocity of this orbit +as seen by a distant observer + + align:start position:0% + + + + align:start position:0% + +okay why am i doing it as seen by a + + align:start position:0% +okay why am i doing it as seen by a + + + align:start position:0% +okay why am i doing it as seen by a +distant observer well when things orbit + + align:start position:0% +distant observer well when things orbit + + + align:start position:0% +distant observer well when things orbit +there tends to be periodicity 'z that + + align:start position:0% +there tends to be periodicity 'z that + + + align:start position:0% +there tends to be periodicity 'z that +imprint themselves on observables it + + align:start position:0% +imprint themselves on observables it + + + align:start position:0% +imprint themselves on observables it +could be the period associate with the + + align:start position:0% +could be the period associate with the + + + align:start position:0% +could be the period associate with the +gravitational wave that rises out of + + align:start position:0% +gravitational wave that rises out of + + + align:start position:0% +gravitational wave that rises out of +this it could be the period associated + + align:start position:0% +this it could be the period associated + + + align:start position:0% +this it could be the period associated +with peaks and a light curve if this is + + align:start position:0% +with peaks and a light curve if this is + + + align:start position:0% +with peaks and a light curve if this is +a star orbiting around a black hole it + + align:start position:0% +a star orbiting around a black hole it + + + align:start position:0% +a star orbiting around a black hole it +could be oscillations in the x-ray flux + + align:start position:0% +could be oscillations in the x-ray flux + + + align:start position:0% +could be oscillations in the x-ray flux +if this is some kind of a lump in an + + align:start position:0% +if this is some kind of a lump in an + + + align:start position:0% +if this is some kind of a lump in an +accretion disk of material orbiting a + + align:start position:0% +accretion disk of material orbiting a + + + align:start position:0% +accretion disk of material orbiting a +black hole so if this is the angular + + align:start position:0% +black hole so if this is the angular + + + align:start position:0% +black hole so if this is the angular +velocity is seen by distant observers + + align:start position:0% +velocity is seen by distant observers + + + align:start position:0% +velocity is seen by distant observers +remember the time that distant observers + + align:start position:0% +remember the time that distant observers + + + align:start position:0% +remember the time that distant observers +use to the time in which the dissin + + align:start position:0% +use to the time in which the dissin + + + align:start position:0% +use to the time in which the dissin +observers clocks run is the Swart shield + + align:start position:0% +observers clocks run is the Swart shield + + + align:start position:0% +observers clocks run is the Swart shield +time T so this will be D Phi DT which I + + align:start position:0% +time T so this will be D Phi DT which I + + + align:start position:0% +time T so this will be D Phi DT which I +can write as D Phi D tau this is the + + align:start position:0% +can write as D Phi D tau this is the + + + align:start position:0% +can write as D Phi D tau this is the +angular velocity according to the orbit + + align:start position:0% +angular velocity according to the orbit + + + align:start position:0% +angular velocity according to the orbit +itself normalized to DT D tau now these + + align:start position:0% +itself normalized to DT D tau now these + + + align:start position:0% +itself normalized to DT D tau now these +are both quantities that are simply + + align:start position:0% +are both quantities that are simply + + + align:start position:0% +are both quantities that are simply +related to constants of the motion + + align:start position:0% +related to constants of the motion + + + align:start position:0% +related to constants of the motion +what I've got in the numerator here is L + + align:start position:0% +what I've got in the numerator here is L + + + align:start position:0% +what I've got in the numerator here is L +hat over R squared and what I've got in + + align:start position:0% +hat over R squared and what I've got in + + + align:start position:0% +hat over R squared and what I've got in +the denominator here is P hat over 1 - I + + align:start position:0% +the denominator here is P hat over 1 - I + + + align:start position:0% +the denominator here is P hat over 1 - I +dropped my G 1 - 2 GM over R so let's go + + align:start position:0% +dropped my G 1 - 2 GM over R so let's go + + + align:start position:0% +dropped my G 1 - 2 GM over R so let's go +ahead and take our solution here my hat + + align:start position:0% +ahead and take our solution here my hat + + + align:start position:0% +ahead and take our solution here my hat +is 1 - 2 GM over R divided by a square + + align:start position:0% +is 1 - 2 GM over R divided by a square + + + align:start position:0% +is 1 - 2 GM over R divided by a square +root of blah blah blah + + align:start position:0% +root of blah blah blah + + + align:start position:0% +root of blah blah blah +the 1 - 2 GM over R cancels my L hat is + + align:start position:0% +the 1 - 2 GM over R cancels my L hat is + + + align:start position:0% +the 1 - 2 GM over R cancels my L hat is +square root GM R divided by again that + + align:start position:0% +square root GM R divided by again that + + + align:start position:0% +square root GM R divided by again that +square root 1 - 3 GM over R notice the + + align:start position:0% +square root 1 - 3 GM over R notice the + + + align:start position:0% +square root 1 - 3 GM over R notice the +square root 1 - 3 GM over R factors all + + align:start position:0% +square root 1 - 3 GM over R factors all + + + align:start position:0% +square root 1 - 3 GM over R factors all +cancel so this becomes plus or minus + + align:start position:0% +cancel so this becomes plus or minus + + + align:start position:0% +cancel so this becomes plus or minus +one over R squared square root GMR looks + + align:start position:0% +one over R squared square root GMR looks + + + align:start position:0% +one over R squared square root GMR looks +like this plus and minus basically just + + align:start position:0% +like this plus and minus basically just + + + align:start position:0% +like this plus and minus basically just +cha respond to whether this motion sort + + align:start position:0% +cha respond to whether this motion sort + + + align:start position:0% +cha respond to whether this motion sort +of is going in the same sense as your + + align:start position:0% +of is going in the same sense as your + + + align:start position:0% +of is going in the same sense as your +Phi coordinate or in the opposite sense + + align:start position:0% +Phi coordinate or in the opposite sense + + + align:start position:0% +Phi coordinate or in the opposite sense +okay there's really no physics than that + + align:start position:0% +okay there's really no physics than that + + + align:start position:0% +okay there's really no physics than that +it's just comes along for the ride that + + align:start position:0% +it's just comes along for the ride that + + + align:start position:0% +it's just comes along for the ride that +both behave the same if you guys get + + align:start position:0% +both behave the same if you guys get + + + align:start position:0% +both behave the same if you guys get +interested in this and you do a similar + + align:start position:0% +interested in this and you do a similar + + + align:start position:0% +interested in this and you do a similar +calculation around a car black hole + + align:start position:0% +calculation around a car black hole + + + align:start position:0% +calculation around a car black hole +you'll find that your pro-grade solution + + align:start position:0% +you'll find that your pro-grade solution + + + align:start position:0% +you'll find that your pro-grade solution +gives you a different frequency than + + align:start position:0% +gives you a different frequency than + + + align:start position:0% +gives you a different frequency than +your a retrograde solution because of + + align:start position:0% +your a retrograde solution because of + + + align:start position:0% +your a retrograde solution because of +the fact that the dragging of inertial + + align:start position:0% +the fact that the dragging of inertial + + + align:start position:0% +the fact that the dragging of inertial +frames due to the spin of the black hole + + align:start position:0% +frames due to the spin of the black hole + + + align:start position:0% +frames due to the spin of the black hole +kind of breaks that symmetry so any + + align:start position:0% +kind of breaks that symmetry so any + + + align:start position:0% +kind of breaks that symmetry so any +which is interesting and well I'll make + + align:start position:0% +which is interesting and well I'll make + + + align:start position:0% +which is interesting and well I'll make +a comment about this in just a second + + align:start position:0% +a comment about this in just a second + + + align:start position:0% +a comment about this in just a second +which is kind of interesting and here's + + align:start position:0% +which is kind of interesting and here's + + + align:start position:0% +which is kind of interesting and here's +what I'll say sometimes people think + + align:start position:0% +what I'll say sometimes people think + + + align:start position:0% +what I'll say sometimes people think +this is more profound than it should be + + align:start position:0% +this is more profound than it should be + + + align:start position:0% +this is more profound than it should be +is this is in fact exactly the same + + align:start position:0% +is this is in fact exactly the same + + + align:start position:0% +is this is in fact exactly the same +frequency law that you get using + + align:start position:0% +frequency law that you get using + + + align:start position:0% +frequency law that you get using +Newtonian gravity this is actually + + align:start position:0% +Newtonian gravity this is actually + + + align:start position:0% +Newtonian gravity this is actually +exactly the same as Kepler's law + + align:start position:0% + + + + align:start position:0% + +that seems really really cool and it is + + align:start position:0% +that seems really really cool and it is + + + align:start position:0% +that seems really really cool and it is +it's actually really useful it makes it + + align:start position:0% +it's actually really useful it makes it + + + align:start position:0% +it's actually really useful it makes it +very easy to remember this ah but don't + + align:start position:0% +very easy to remember this ah but don't + + + align:start position:0% +very easy to remember this ah but don't +read too much into it okay it is more + + align:start position:0% +read too much into it okay it is more + + + align:start position:0% +read too much into it okay it is more +than anything it is a statement about a + + align:start position:0% +than anything it is a statement about a + + + align:start position:0% +than anything it is a statement about a +particular quality of this radial + + align:start position:0% +particular quality of this radial + + + align:start position:0% +particular quality of this radial +coordinate so remember and Newtonian + + align:start position:0% +coordinate so remember and Newtonian + + + align:start position:0% +coordinate so remember and Newtonian +gravity are tells me the distance + + align:start position:0% +gravity are tells me the distance + + + align:start position:0% +gravity are tells me the distance +between if I have an orbit at r1 and an + + align:start position:0% +between if I have an orbit at r1 and an + + + align:start position:0% +between if I have an orbit at r1 and an +orbit at r2 then I know that the + + align:start position:0% +orbit at r2 then I know that the + + + align:start position:0% +orbit at r2 then I know that the +distance between them is R two minus R + + align:start position:0% +distance between them is R two minus R + + + align:start position:0% +distance between them is R two minus R +one in the Schwarzschild space-time the + + align:start position:0% +one in the Schwarzschild space-time the + + + align:start position:0% +one in the Schwarzschild space-time the +distance between these two orbits is not + + align:start position:0% +distance between these two orbits is not + + + align:start position:0% +distance between these two orbits is not +r2 minus r1 however our two labels a + + align:start position:0% +r2 minus r1 however our two labels a + + + align:start position:0% +r2 minus r1 however our two labels a +sphere of surface area for pie r2 + + align:start position:0% +sphere of surface area for pie r2 + + + align:start position:0% +sphere of surface area for pie r2 +squared + r1 labels a sphere of surface + + align:start position:0% +squared + r1 labels a sphere of surface + + + align:start position:0% +squared + r1 labels a sphere of surface +area for pie r1 squared it's easy to + + align:start position:0% +area for pie r1 squared it's easy to + + + align:start position:0% +area for pie r1 squared it's easy to +also show that the circumference of the + + align:start position:0% +also show that the circumference of the + + + align:start position:0% +also show that the circumference of the +orbit at r2 is 2 PI R 2 the + + align:start position:0% +orbit at r2 is 2 PI R 2 the + + + align:start position:0% +orbit at r2 is 2 PI R 2 the +circumference of the orbit at r1 is 2 pi + + align:start position:0% +circumference of the orbit at r1 is 2 pi + + + align:start position:0% +circumference of the orbit at r1 is 2 pi +r1 that more than anything is why we end + + align:start position:0% +r1 that more than anything is why we end + + + align:start position:0% +r1 that more than anything is why we end +up reproducing Kepler's law here is that + + align:start position:0% +up reproducing Kepler's law here is that + + + align:start position:0% +up reproducing Kepler's law here is that +this aerial coordinate is nicely + + align:start position:0% +this aerial coordinate is nicely + + + align:start position:0% +this aerial coordinate is nicely +amenable to this interpretation so is + + align:start position:0% +amenable to this interpretation so is + + + align:start position:0% +amenable to this interpretation so is +this orbit so I described over here an + + align:start position:0% +this orbit so I described over here an + + + align:start position:0% +this orbit so I described over here an +orbit that is unstable in an orbit that + + align:start position:0% +orbit that is unstable in an orbit that + + + align:start position:0% +orbit that is unstable in an orbit that +is stable I have described how to + + align:start position:0% +is stable I have described how to + + + align:start position:0% +is stable I have described how to +compute if I want to find a circular + + align:start position:0% +compute if I want to find a circular + + + align:start position:0% +compute if I want to find a circular +orbit at a given radius those formulas + + align:start position:0% +orbit at a given radius those formulas + + + align:start position:0% +orbit at a given radius those formulas +that I derived over there on the right + + align:start position:0% +that I derived over there on the right + + + align:start position:0% +that I derived over there on the right +most blackboards they tell me what the + + align:start position:0% +most blackboards they tell me what the + + + align:start position:0% +most blackboards they tell me what the +energy and the annual annual momentum + + align:start position:0% +energy and the annual annual momentum + + + align:start position:0% +energy and the annual annual momentum +needs to be as a function of R is that + + align:start position:0% +needs to be as a function of R is that + + + align:start position:0% +needs to be as a function of R is that +orbit stable well if it is I can check + + align:start position:0% +orbit stable well if it is I can check + + + align:start position:0% +orbit stable well if it is I can check +that by computing the second derivative + + align:start position:0% +that by computing the second derivative + + + align:start position:0% +that by computing the second derivative +of my effective potential + + align:start position:0% + + + + align:start position:0% + +so my orbits are stable if the second + + align:start position:0% +so my orbits are stable if the second + + + align:start position:0% +so my orbits are stable if the second +derivative with respect to R is greater + + align:start position:0% +derivative with respect to R is greater + + + align:start position:0% +derivative with respect to R is greater +than zero unstable if this turns out to + + align:start position:0% +than zero unstable if this turns out to + + + align:start position:0% +than zero unstable if this turns out to +be negative let's look at the crossover + + align:start position:0% +be negative let's look at the crossover + + + align:start position:0% +be negative let's look at the crossover +point from one to the other what if + + align:start position:0% +point from one to the other what if + + + align:start position:0% +point from one to the other what if +there is a radius where in fact the + + align:start position:0% +there is a radius where in fact the + + + align:start position:0% +there is a radius where in fact the +stable and the unstable orbits coincide + + align:start position:0% +stable and the unstable orbits coincide + + + align:start position:0% +stable and the unstable orbits coincide +in fact what winds finds if you look at + + align:start position:0% +in fact what winds finds if you look at + + + align:start position:0% +in fact what winds finds if you look at +the effective potential you imagine just + + align:start position:0% +the effective potential you imagine just + + + align:start position:0% +the effective potential you imagine just +sort of playing with L sub Z okay so + + align:start position:0% +sort of playing with L sub Z okay so + + + align:start position:0% +sort of playing with L sub Z okay so +let's say we take that L sub C and we + + align:start position:0% +let's say we take that L sub C and we + + + align:start position:0% +let's say we take that L sub C and we +just explore it for lots of different + + align:start position:0% +just explore it for lots of different + + + align:start position:0% +just explore it for lots of different +radii of the orbits you find that as the + + align:start position:0% +radii of the orbits you find that as the + + + align:start position:0% +radii of the orbits you find that as the +orbits radius gets smaller and smaller + + align:start position:0% +orbits radius gets smaller and smaller + + + align:start position:0% +orbits radius gets smaller and smaller +your stable orbit tends to go up and + + align:start position:0% +your stable orbit tends to go up and + + + align:start position:0% +your stable orbit tends to go up and +this minimum sort of becomes flatter and + + align:start position:0% +this minimum sort of becomes flatter and + + + align:start position:0% +this minimum sort of becomes flatter and +your unstable orbits on it comes down + + align:start position:0% +your unstable orbits on it comes down + + + align:start position:0% +your unstable orbits on it comes down +they sort of approach one another there + + align:start position:0% +they sort of approach one another there + + + align:start position:0% +they sort of approach one another there +is a point just when they coincide they + + align:start position:0% +is a point just when they coincide they + + + align:start position:0% +is a point just when they coincide they +should have an effective on it my + + align:start position:0% +should have an effective on it my + + + align:start position:0% +should have an effective on it my +apologies + + align:start position:0% + + + + align:start position:0% + +right when they coincide this defines + + align:start position:0% +right when they coincide this defines + + + align:start position:0% +right when they coincide this defines +what we call the marginally stable orbit + + align:start position:0% + + + + align:start position:0% + +okay I may have put this on a problem + + align:start position:0% +okay I may have put this on a problem + + + align:start position:0% +okay I may have put this on a problem +set but it might be one of the ones I + + align:start position:0% +set but it might be one of the ones I + + + align:start position:0% +set but it might be one of the ones I +say to drop so I'm just gonna go ahead + + align:start position:0% +say to drop so I'm just gonna go ahead + + + align:start position:0% +say to drop so I'm just gonna go ahead +and do the analysis when you compute + + align:start position:0% +and do the analysis when you compute + + + align:start position:0% +and do the analysis when you compute +this bearing in mind that your angular + + align:start position:0% +this bearing in mind that your angular + + + align:start position:0% +this bearing in mind that your angular +momentum is a constant so take this + + align:start position:0% +momentum is a constant so take this + + + align:start position:0% +momentum is a constant so take this +substitute in now your solution for L + + align:start position:0% +substitute in now your solution for L + + + align:start position:0% +substitute in now your solution for L +sub Z which I've written down over there + + align:start position:0% + + + + align:start position:0% + +what you find is that the marginally + + align:start position:0% +what you find is that the marginally + + + align:start position:0% +what you find is that the marginally +stable orbit let's call it R sub M s it + + align:start position:0% +stable orbit let's call it R sub M s it + + + align:start position:0% +stable orbit let's call it R sub M s it +is located at a radius of 6 GM this is a + + align:start position:0% +is located at a radius of 6 GM this is a + + + align:start position:0% +is located at a radius of 6 GM this is a +profoundly new behavior that doesn't + + align:start position:0% +profoundly new behavior that doesn't + + + align:start position:0% +profoundly new behavior that doesn't +even come close to existing in Newtonian + + align:start position:0% +even come close to existing in Newtonian + + + align:start position:0% +even come close to existing in Newtonian +space lines doesn't come close to + + align:start position:0% +space lines doesn't come close to + + + align:start position:0% +space lines doesn't come close to +existing in Newtonian gravity excuse me + + align:start position:0% + + + + align:start position:0% + +the message I want you to understand is + + align:start position:0% +the message I want you to understand is + + + align:start position:0% +the message I want you to understand is +that what this tells us is that no + + align:start position:0% +that what this tells us is that no + + + align:start position:0% +that what this tells us is that no +stable circular orbits exists inside our + + align:start position:0% +stable circular orbits exists inside our + + + align:start position:0% +stable circular orbits exists inside our +equals + + align:start position:0% +equals + + + align:start position:0% +equals +6g so this is very very different + + align:start position:0% +6g so this is very very different + + + align:start position:0% +6g so this is very very different +behavior okay if I have and let's just + + align:start position:0% +behavior okay if I have and let's just + + + align:start position:0% +behavior okay if I have and let's just +say I have a very compact body but + + align:start position:0% +say I have a very compact body but + + + align:start position:0% +say I have a very compact body but +Newtonian gravity rules I can make + + align:start position:0% +Newtonian gravity rules I can make + + + align:start position:0% +Newtonian gravity rules I can make +circular orbits around it's basically go + + align:start position:0% +circular orbits around it's basically go + + + align:start position:0% +circular orbits around it's basically go +all the way down until they essentially + + align:start position:0% +all the way down until they essentially + + + align:start position:0% +all the way down until they essentially +touch the surface of that body and you + + align:start position:0% +touch the surface of that body and you + + + align:start position:0% +touch the surface of that body and you +might think based on this that you would + + align:start position:0% +might think based on this that you would + + + align:start position:0% +might think based on this that you would +want to make orbits that basically go + + align:start position:0% +want to make orbits that basically go + + + align:start position:0% +want to make orbits that basically go +all the way down that sort of kiss the + + align:start position:0% +all the way down that sort of kiss the + + + align:start position:0% +all the way down that sort of kiss the +edge of our equals to G M well this is + + align:start position:0% +edge of our equals to G M well this is + + + align:start position:0% +edge of our equals to G M well this is +telling you you can't do that when you + + align:start position:0% +telling you you can't do that when you + + + align:start position:0% +telling you you can't do that when you +get when you start trying to make orbits + + align:start position:0% +get when you start trying to make orbits + + + align:start position:0% +get when you start trying to make orbits +that go inside at least circulars that + + align:start position:0% +that go inside at least circulars that + + + align:start position:0% +that go inside at least circulars that +go inside 6gm they're not stable + + align:start position:0% +go inside 6gm they're not stable + + + align:start position:0% +go inside 6gm they're not stable +if someone sneezes on them they either + + align:start position:0% +if someone sneezes on them they either + + + align:start position:0% +if someone sneezes on them they either +are sort of blown out to infinity or + + align:start position:0% +are sort of blown out to infinity or + + + align:start position:0% +are sort of blown out to infinity or +they fall into the event horizon and in + + align:start position:0% +they fall into the event horizon and in + + + align:start position:0% +they fall into the event horizon and in +fact one of the consequences of this is + + align:start position:0% +fact one of the consequences of this is + + + align:start position:0% +fact one of the consequences of this is +that in Astrophysical systems we + + align:start position:0% +that in Astrophysical systems we + + + align:start position:0% +that in Astrophysical systems we +generically expect there to be kind of + + align:start position:0% +generically expect there to be kind of + + + align:start position:0% +generically expect there to be kind of +if you imagine material falling into a + + align:start position:0% +if you imagine material falling into a + + + align:start position:0% +if you imagine material falling into a +black hole imagine that there's like a + + align:start position:0% +black hole imagine that there's like a + + + align:start position:0% +black hole imagine that there's like a +star or something dumping gas into orbit + + align:start position:0% +star or something dumping gas into orbit + + + align:start position:0% +star or something dumping gas into orbit +around the black hole well it will tend + + align:start position:0% +around the black hole well it will tend + + + align:start position:0% +around the black hole well it will tend +to form a disk that orbits around this + + align:start position:0% +to form a disk that orbits around this + + + align:start position:0% +to form a disk that orbits around this +thing and the elements of the disk are + + align:start position:0% +thing and the elements of the disk are + + + align:start position:0% +thing and the elements of the disk are +always rubbing against each other and + + align:start position:0% +always rubbing against each other and + + + align:start position:0% +always rubbing against each other and +radiating that makes them get hot they + + align:start position:0% +radiating that makes them get hot they + + + align:start position:0% +radiating that makes them get hot they +lose energy because of this radiation + + align:start position:0% +lose energy because of this radiation + + + align:start position:0% +lose energy because of this radiation +and so they will very slowly sort of + + align:start position:0% +and so they will very slowly sort of + + + align:start position:0% +and so they will very slowly sort of +fall in but they make this kind of it's + + align:start position:0% +fall in but they make this kind of it's + + + align:start position:0% +fall in but they make this kind of it's +thought that in most cases that will + + align:start position:0% +thought that in most cases that will + + + align:start position:0% +thought that in most cases that will +make this kind of thick desk that fills + + align:start position:0% +make this kind of thick desk that fills + + + align:start position:0% +make this kind of thick desk that fills +much of the space-time surrounding the + + align:start position:0% +much of the space-time surrounding the + + + align:start position:0% +much of the space-time surrounding the +black hole but there'll be a hole in the + + align:start position:0% +black hole but there'll be a hole in the + + + align:start position:0% +black hole but there'll be a hole in the +center not just because the thing is a + + align:start position:0% +center not just because the thing is a + + + align:start position:0% +center not just because the thing is a +black hole okay I don't mean that kind + + align:start position:0% +black hole okay I don't mean that kind + + + align:start position:0% +black hole okay I don't mean that kind +of a hole though actually be something + + align:start position:0% +of a hole though actually be something + + + align:start position:0% +of a hole though actually be something +surrounding the black hole's event + + align:start position:0% +surrounding the black hole's event + + + align:start position:0% +surrounding the black hole's event +horizon because there are no stable + + align:start position:0% +horizon because there are no stable + + + align:start position:0% +horizon because there are no stable +circular orbits once the material comes + + align:start position:0% +circular orbits once the material comes + + + align:start position:0% +circular orbits once the material comes +in and hits this this particular radius + + align:start position:0% +in and hits this this particular radius + + + align:start position:0% +in and hits this this particular radius +6gm in the short Shield case it very + + align:start position:0% +6gm in the short Shield case it very + + + align:start position:0% +6gm in the short Shield case it very +rapidly falls in reach + + align:start position:0% +rapidly falls in reach + + + align:start position:0% +rapidly falls in reach +is the density of that material + + align:start position:0% +is the density of that material + + + align:start position:0% +is the density of that material +tremendously and you get this much + + align:start position:0% +tremendously and you get this much + + + align:start position:0% +tremendously and you get this much +thinner region of the disk where + + align:start position:0% +thinner region of the disk where + + + align:start position:0% +thinner region of the disk where +essentially things fall in practically + + align:start position:0% +essentially things fall in practically + + + align:start position:0% +essentially things fall in practically +instantly it shouldn't be noted that + + align:start position:0% +instantly it shouldn't be noted that + + + align:start position:0% +instantly it shouldn't be noted that +this 6gm is of course only four Schwartz + + align:start position:0% +this 6gm is of course only four Schwartz + + + align:start position:0% +this 6gm is of course only four Schwartz +yield if you talk about kur you actually + + align:start position:0% +yield if you talk about kur you actually + + + align:start position:0% +yield if you talk about kur you actually +have two different radii corresponding + + align:start position:0% +have two different radii corresponding + + + align:start position:0% +have two different radii corresponding +to material that goes around parallel to + + align:start position:0% +to material that goes around parallel to + + + align:start position:0% +to material that goes around parallel to +the black hole's spin a material that + + align:start position:0% +the black hole's spin a material that + + + align:start position:0% +the black hole's spin a material that +goes anti parallel to the black hole + + align:start position:0% +goes anti parallel to the black hole + + + align:start position:0% +goes anti parallel to the black hole +spin + + align:start position:0% +spin + + + align:start position:0% +spin +okay and it complicates things somewhat + + align:start position:0% +okay and it complicates things somewhat + + + align:start position:0% +okay and it complicates things somewhat +there's two different radii there the + + align:start position:0% +there's two different radii there the + + + align:start position:0% +there's two different radii there the +one that goes parallel tends to get a + + align:start position:0% +one that goes parallel tends to get a + + + align:start position:0% +one that goes parallel tends to get a +little bit closer + + align:start position:0% +little bit closer + + + align:start position:0% +little bit closer +well it's anti parallel tends to go out + + align:start position:0% +well it's anti parallel tends to go out + + + align:start position:0% +well it's anti parallel tends to go out +a little bit farther but the general + + align:start position:0% +a little bit farther but the general + + + align:start position:0% +a little bit farther but the general +prediction that there's an innermost + + align:start position:0% +prediction that there's an innermost + + + align:start position:0% +prediction that there's an innermost +orbit beyond which stable orbits do not + + align:start position:0% +orbit beyond which stable orbits do not + + + align:start position:0% +orbit beyond which stable orbits do not +exist that's robust and holds across the + + align:start position:0% +exist that's robust and holds across the + + + align:start position:0% +exist that's robust and holds across the +domain of black holes so let me conclude + + align:start position:0% +domain of black holes so let me conclude + + + align:start position:0% +domain of black holes so let me conclude +by talking about one final category of + + align:start position:0% +by talking about one final category of + + + align:start position:0% +by talking about one final category of +orbits photonic orbits + + align:start position:0% + + + + align:start position:0% + +so let's recall that when we were + + align:start position:0% +so let's recall that when we were + + + align:start position:0% +so let's recall that when we were +talking about null geodesics we + + align:start position:0% +talking about null geodesics we + + + align:start position:0% +talking about null geodesics we +parameterize them in such a way that D + + align:start position:0% +parameterize them in such a way that D + + + align:start position:0% +parameterize them in such a way that D +sort of the tangent to the world line + + align:start position:0% +sort of the tangent to the world line + + + align:start position:0% +sort of the tangent to the world line +has an affine parameter attached to it + + align:start position:0% + + + + align:start position:0% + +such that we can write P equals DX D + + align:start position:0% +such that we can write P equals DX D + + + align:start position:0% +such that we can write P equals DX D +lambda okay these guys are null so P key + + align:start position:0% +lambda okay these guys are null so P key + + + align:start position:0% +lambda okay these guys are null so P key +equals zero for the case of orbiting + + align:start position:0% +equals zero for the case of orbiting + + + align:start position:0% +equals zero for the case of orbiting +bodies that was equal to minus mass + + align:start position:0% +bodies that was equal to minus mass + + + align:start position:0% +bodies that was equal to minus mass +squared mass is zero here so we're gonna + + align:start position:0% +squared mass is zero here so we're gonna + + + align:start position:0% +squared mass is zero here so we're gonna +follow a very similar procedure okay the + + align:start position:0% +follow a very similar procedure okay the + + + align:start position:0% +follow a very similar procedure okay the +space-time is still time independent so + + align:start position:0% +space-time is still time independent so + + + align:start position:0% +space-time is still time independent so +there is still a notion of a conserved + + align:start position:0% +there is still a notion of a conserved + + + align:start position:0% +there is still a notion of a conserved +energy it is still actually symmetric so + + align:start position:0% +energy it is still actually symmetric so + + + align:start position:0% +energy it is still actually symmetric so +there is still a notion of axial angular + + align:start position:0% +there is still a notion of axial angular + + + align:start position:0% +there is still a notion of axial angular +momentum but because P dot P is zero now + + align:start position:0% +momentum but because P dot P is zero now + + + align:start position:0% +momentum but because P dot P is zero now +rather than minus M Squared when we go + + align:start position:0% +rather than minus M Squared when we go + + + align:start position:0% +rather than minus M Squared when we go +through the exercise of that sort of + + align:start position:0% +through the exercise of that sort of + + + align:start position:0% +through the exercise of that sort of +parallels what we did for our massive + + align:start position:0% +parallels what we did for our massive + + + align:start position:0% +parallels what we did for our massive +particle we're going to derive a + + align:start position:0% +particle we're going to derive a + + + align:start position:0% +particle we're going to derive a +different potential so let's go ahead + + align:start position:0% +different potential so let's go ahead + + + align:start position:0% +different potential so let's go ahead +and evaluate this guy again I get zero + + align:start position:0% +and evaluate this guy again I get zero + + + align:start position:0% +and evaluate this guy again I get zero +equals minus 1 minus 2 GM over R DT D + + align:start position:0% +equals minus 1 minus 2 GM over R DT D + + + align:start position:0% +equals minus 1 minus 2 GM over R DT D +lambda squared plus 1 minus 2 GM over r + + align:start position:0% +lambda squared plus 1 minus 2 GM over r + + + align:start position:0% +lambda squared plus 1 minus 2 GM over r +dr d lambda squared I'm still going to + + align:start position:0% +dr d lambda squared I'm still going to + + + align:start position:0% +dr d lambda squared I'm still going to +require this thing to be in the theta + + align:start position:0% +require this thing to be in the theta + + + align:start position:0% +require this thing to be in the theta +equals PI over 2 plane so let me know + + align:start position:0% +equals PI over 2 plane so let me know + + + align:start position:0% +equals PI over 2 plane so let me know +seda term and I've set Santa to PI over + + align:start position:0% +seda term and I've set Santa to PI over + + + align:start position:0% +seda term and I've set Santa to PI over +2 so my sine squared theta is just 1 + + align:start position:0% + + + + align:start position:0% + +do I get this I'll remind you that I can + + align:start position:0% +do I get this I'll remind you that I can + + + align:start position:0% +do I get this I'll remind you that I can +relate so that the the relationship + + align:start position:0% +relate so that the the relationship + + + align:start position:0% +relate so that the the relationship +between the time light complan of + + align:start position:0% +between the time light complan of + + + align:start position:0% +between the time light complan of +momentum and energy the actual component + + align:start position:0% +momentum and energy the actual component + + + align:start position:0% +momentum and energy the actual component +of momentum and yang momentum it's + + align:start position:0% +of momentum and yang momentum it's + + + align:start position:0% +of momentum and yang momentum it's +exactly the same as before there's no + + align:start position:0% +exactly the same as before there's no + + + align:start position:0% +exactly the same as before there's no +rest mass appearing and so now I find so + + align:start position:0% +rest mass appearing and so now I find so + + + align:start position:0% +rest mass appearing and so now I find so +my energy I don't put a hat on it it's + + align:start position:0% +my energy I don't put a hat on it it's + + + align:start position:0% +my energy I don't put a hat on it it's +not energy bringing it mass cuz there is + + align:start position:0% +not energy bringing it mass cuz there is + + + align:start position:0% +not energy bringing it mass cuz there is +no mass that looks like so and my L + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% + + + + align:start position:0% + +using them I can now derive an equation + + align:start position:0% +using them I can now derive an equation + + + align:start position:0% +using them I can now derive an equation +governing the radial motion of my light + + align:start position:0% +governing the radial motion of my light + + + align:start position:0% +governing the radial motion of my light +ray and sparing you the line or two of + + align:start position:0% +ray and sparing you the line or two of + + + align:start position:0% +ray and sparing you the line or two of +algebra it looks like this okay so kind + + align:start position:0% +algebra it looks like this okay so kind + + + align:start position:0% +algebra it looks like this okay so kind +of similar to what we had before if you + + align:start position:0% +of similar to what we had before if you + + + align:start position:0% +of similar to what we had before if you +look at it you'll see the term involving + + align:start position:0% +look at it you'll see the term involving + + + align:start position:0% +look at it you'll see the term involving +the angular momentum is a little bit + + align:start position:0% +the angular momentum is a little bit + + + align:start position:0% +the angular momentum is a little bit +different as you stare at this for a + + align:start position:0% +different as you stare at this for a + + + align:start position:0% +different as you stare at this for a +moment something should be disturbing + + align:start position:0% +moment something should be disturbing + + + align:start position:0% +moment something should be disturbing +you notice that the equation of motion + + align:start position:0% +you notice that the equation of motion + + + align:start position:0% +you notice that the equation of motion +appears to depend on the energy okay + + align:start position:0% +appears to depend on the energy okay + + + align:start position:0% +appears to depend on the energy okay +that should really bug you + + align:start position:0% +that should really bug you + + + align:start position:0% +that should really bug you +why should gamma rays and infrared + + align:start position:0% +why should gamma rays and infrared + + + align:start position:0% +why should gamma rays and infrared +radiation follow different trajectories + + align:start position:0% +radiation follow different trajectories + + + align:start position:0% +radiation follow different trajectories +okay as long as I am truly in a + + align:start position:0% +okay as long as I am truly in a + + + align:start position:0% +okay as long as I am truly in a +geometric optics limit + + align:start position:0% +geometric optics limit + + + align:start position:0% +geometric optics limit +I shouldn't okay now it is true that if + + align:start position:0% +I shouldn't okay now it is true that if + + + align:start position:0% +I shouldn't okay now it is true that if +you consider very long wavelength + + align:start position:0% +you consider very long wavelength + + + align:start position:0% +you consider very long wavelength +radiation you might need to worry about + + align:start position:0% +radiation you might need to worry about + + + align:start position:0% +radiation you might need to worry about +things you might need to solve the wave + + align:start position:0% +things you might need to solve the wave + + + align:start position:0% +things you might need to solve the wave +equation in the space-time but as long + + align:start position:0% +equation in the space-time but as long + + + align:start position:0% +equation in the space-time but as long +as the wave nature of this radiation is + + align:start position:0% +as the wave nature of this radiation is + + + align:start position:0% +as the wave nature of this radiation is +if the wavelength is small enough that + + align:start position:0% +if the wavelength is small enough that + + + align:start position:0% +if the wavelength is small enough that +it's negligible compared to to GM I + + align:start position:0% +it's negligible compared to to GM I + + + align:start position:0% +it's negligible compared to to GM I +shouldn't care what the energy is energy + + align:start position:0% +shouldn't care what the energy is energy + + + align:start position:0% +shouldn't care what the energy is energy +should not be influencing this okay and + + align:start position:0% +should not be influencing this okay and + + + align:start position:0% +should not be influencing this okay and +so what's going on is I need to repr + + align:start position:0% +so what's going on is I need to repr + + + align:start position:0% +so what's going on is I need to repr +amateur eyes this a little bit what I'm + + align:start position:0% +amateur eyes this a little bit what I'm + + + align:start position:0% +amateur eyes this a little bit what I'm +going to do to wash away my dependence + + align:start position:0% +going to do to wash away my dependence + + + align:start position:0% +going to do to wash away my dependence +on wash away my apparent dependence on + + align:start position:0% +on wash away my apparent dependence on + + + align:start position:0% +on wash away my apparent dependence on +the energy here is I'm going to redefine + + align:start position:0% +the energy here is I'm going to redefine + + + align:start position:0% +the energy here is I'm going to redefine +my affine parameter + + align:start position:0% + + + + align:start position:0% + +so let's take lambda 2 L divided by + + align:start position:0% +so let's take lambda 2 L divided by + + + align:start position:0% +so let's take lambda 2 L divided by +lambda and I am going to define B to be + + align:start position:0% +lambda and I am going to define B to be + + + align:start position:0% +lambda and I am going to define B to be +L divided by e this is a quantity that I + + align:start position:0% +L divided by e this is a quantity that I + + + align:start position:0% +L divided by e this is a quantity that I +will call the impact parameter and I'll + + align:start position:0% +will call the impact parameter and I'll + + + align:start position:0% +will call the impact parameter and I'll +describe why I'm calling it that in just + + align:start position:0% +describe why I'm calling it that in just + + + align:start position:0% +describe why I'm calling it that in just +a few minutes so I'm going to take this + + align:start position:0% +a few minutes so I'm going to take this + + + align:start position:0% +a few minutes so I'm going to take this +entire equation divide both sides by l + + align:start position:0% +entire equation divide both sides by l + + + align:start position:0% +entire equation divide both sides by l +squared and I get something that looks + + align:start position:0% +squared and I get something that looks + + + align:start position:0% +squared and I get something that looks +like this + + align:start position:0% + + + + align:start position:0% + +what I'm gonna do is say that the impact + + align:start position:0% +what I'm gonna do is say that the impact + + + align:start position:0% +what I'm gonna do is say that the impact +parameter B is what I can control + + align:start position:0% +parameter B is what I can control + + + align:start position:0% +parameter B is what I can control +it's the parameter that I like and + + align:start position:0% +it's the parameter that I like and + + + align:start position:0% +it's the parameter that I like and +control that defines the photon that I + + align:start position:0% +control that defines the photon that I + + + align:start position:0% +control that defines the photon that I +am studying here and everything after + + align:start position:0% +am studying here and everything after + + + align:start position:0% +am studying here and everything after +this this is my photon potential notice + + align:start position:0% +this this is my photon potential notice + + + align:start position:0% +this this is my photon potential notice +that the photon potential the photon + + align:start position:0% +that the photon potential the photon + + + align:start position:0% +that the photon potential the photon +potential has no free parameters in it + + align:start position:0% + + + + align:start position:0% + +if I plot this guy as a function of our + + align:start position:0% + + + + align:start position:0% + +kind it just looks like this okay + + align:start position:0% +kind it just looks like this okay + + + align:start position:0% +kind it just looks like this okay +two aspects of it are worth calling out + + align:start position:0% + + + + align:start position:0% + +this peak occurs at R equals three R + + align:start position:0% +this peak occurs at R equals three R + + + align:start position:0% +this peak occurs at R equals three R +equals 3 GM remember the way in which + + align:start position:0% +equals 3 GM remember the way in which + + + align:start position:0% +equals 3 GM remember the way in which +our energy still happen on the board + + align:start position:0% +our energy still happen on the board + + + align:start position:0% +our energy still happen on the board +here stings like the energy per unit + + align:start position:0% +here stings like the energy per unit + + + align:start position:0% +here stings like the energy per unit +mass and the angular mentum per unit + + align:start position:0% +mass and the angular mentum per unit + + + align:start position:0% +mass and the angular mentum per unit +mass all blew up when R equaled 3 GM 3 + + align:start position:0% +mass all blew up when R equaled 3 GM 3 + + + align:start position:0% +mass all blew up when R equaled 3 GM 3 +GM is showing up now when I look at the + + align:start position:0% +GM is showing up now when I look at the + + + align:start position:0% +GM is showing up now when I look at the +motion of radiation ok look at massless + + align:start position:0% +motion of radiation ok look at massless + + + align:start position:0% +motion of radiation ok look at massless +radiation corresponding to a massless + + align:start position:0% +radiation corresponding to a massless + + + align:start position:0% +radiation corresponding to a massless +particle so to speak if I look at the + + align:start position:0% +particle so to speak if I look at the + + + align:start position:0% +particle so to speak if I look at the +energy per unit mass and the mass goes + + align:start position:0% +energy per unit mass and the mass goes + + + align:start position:0% +energy per unit mass and the mass goes +to 0 I get infinity so the fact that I + + align:start position:0% +to 0 I get infinity so the fact that I + + + align:start position:0% +to 0 I get infinity so the fact that I +was actually seeing sort of things + + align:start position:0% +was actually seeing sort of things + + + align:start position:0% +was actually seeing sort of things +blowing up as R goes to 3 GM was kind of + + align:start position:0% +blowing up as R goes to 3 GM was kind of + + + align:start position:0% +blowing up as R goes to 3 GM was kind of +like the equations hinting to me in + + align:start position:0% +like the equations hinting to me in + + + align:start position:0% +like the equations hinting to me in +advance that there was a hidden solution + + align:start position:0% +advance that there was a hidden solution + + + align:start position:0% +advance that there was a hidden solution +correspond to radiation that could be + + align:start position:0% +correspond to radiation that could be + + + align:start position:0% +correspond to radiation that could be +regarded as a particular limit that they + + align:start position:0% +regarded as a particular limit that they + + + align:start position:0% +regarded as a particular limit that they +were sort of struggling to communicate + + align:start position:0% +were sort of struggling to communicate + + + align:start position:0% +were sort of struggling to communicate +to me the earth in which I want to note + + align:start position:0% +to me the earth in which I want to note + + + align:start position:0% +to me the earth in which I want to note +is that the potential the height of the + + align:start position:0% +is that the potential the height of the + + + align:start position:0% +is that the potential the height of the +potential right here + + align:start position:0% + + + + align:start position:0% + +it has a peak value of 1 over 27 G + + align:start position:0% +it has a peak value of 1 over 27 G + + + align:start position:0% +it has a peak value of 1 over 27 G +squared M Squared okay hold that thought + + align:start position:0% +squared M Squared okay hold that thought + + + align:start position:0% +squared M Squared okay hold that thought +for just a moment actually let me write + + align:start position:0% +for just a moment actually let me write + + + align:start position:0% +for just a moment actually let me write +it in a slightly different way this + + align:start position:0% +it in a slightly different way this + + + align:start position:0% +it in a slightly different way this +equals 1 over 3 root 3 G M squared so + + align:start position:0% +equals 1 over 3 root 3 G M squared so + + + align:start position:0% +equals 1 over 3 root 3 G M squared so +now to wrap this up I need to tell you + + align:start position:0% +now to wrap this up I need to tell you + + + align:start position:0% +now to wrap this up I need to tell you +what is really meant by this impact + + align:start position:0% +what is really meant by this impact + + + align:start position:0% +what is really meant by this impact +parameter + + align:start position:0% + + + + align:start position:0% + +so go back to freshman mechanics and + + align:start position:0% +so go back to freshman mechanics and + + + align:start position:0% +so go back to freshman mechanics and +impact parameter there is like let's say + + align:start position:0% +impact parameter there is like let's say + + + align:start position:0% +impact parameter there is like let's say +I have a problem where I am looking at I + + align:start position:0% + + + + align:start position:0% + +am looking at an object that is on an in + + align:start position:0% +am looking at an object that is on an in + + + align:start position:0% +am looking at an object that is on an in +fall trajectory there's a momentum P + + align:start position:0% +fall trajectory there's a momentum P + + + align:start position:0% +fall trajectory there's a momentum P +that is describing this and it's moving + + align:start position:0% +that is describing this and it's moving + + + align:start position:0% +that is describing this and it's moving +in such a way it's not moving on a + + align:start position:0% +in such a way it's not moving on a + + + align:start position:0% +in such a way it's not moving on a +radial trajectory all right it's + + align:start position:0% +radial trajectory all right it's + + + align:start position:0% +radial trajectory all right it's +actually moving in a sense that is a + + align:start position:0% +actually moving in a sense that is a + + + align:start position:0% +actually moving in a sense that is a +little bit off of true to the radial + + align:start position:0% +little bit off of true to the radial + + + align:start position:0% +little bit off of true to the radial +direction okay this guy actually has an + + align:start position:0% +direction okay this guy actually has an + + + align:start position:0% +direction okay this guy actually has an +angular momentum that is given by let's + + align:start position:0% +angular momentum that is given by let's + + + align:start position:0% +angular momentum that is given by let's +say that this is equal to PX this is be + + align:start position:0% +say that this is equal to PX this is be + + + align:start position:0% +say that this is equal to PX this is be +Y hat this guy's got an angular momentum + + align:start position:0% +Y hat this guy's got an angular momentum + + + align:start position:0% +Y hat this guy's got an angular momentum +a B cross P okay that's the impact + + align:start position:0% +a B cross P okay that's the impact + + + align:start position:0% +a B cross P okay that's the impact +parameter associated with this thing it + + align:start position:0% +parameter associated with this thing it + + + align:start position:0% +parameter associated with this thing it +sort of tells me about this the the + + align:start position:0% +sort of tells me about this the the + + + align:start position:0% +sort of tells me about this the the +offset of this momentum from being + + align:start position:0% +offset of this momentum from being + + + align:start position:0% +offset of this momentum from being +directly radial towards the center of + + align:start position:0% +directly radial towards the center of + + + align:start position:0% +directly radial towards the center of +this object + + align:start position:0% + + + + align:start position:0% + +well I'm going to use a similar notion + + align:start position:0% +well I'm going to use a similar notion + + + align:start position:0% +well I'm going to use a similar notion +to give me a geometric sense of what + + align:start position:0% +to give me a geometric sense of what + + + align:start position:0% +to give me a geometric sense of what +this impact parameter here means suppose + + align:start position:0% +this impact parameter here means suppose + + + align:start position:0% +this impact parameter here means suppose +here is my black hole this is a little + + align:start position:0% +here is my black hole this is a little + + + align:start position:0% +here is my black hole this is a little +circle of radius 2 g-m and I'm sitting + + align:start position:0% +circle of radius 2 g-m and I'm sitting + + + align:start position:0% +circle of radius 2 g-m and I'm sitting +where the heck out here safely far away + + align:start position:0% +where the heck out here safely far away + + + align:start position:0% +where the heck out here safely far away +from this thing + + align:start position:0% + + + + align:start position:0% + +and what I'm going to do is shoot light + + align:start position:0% +and what I'm going to do is shoot light + + + align:start position:0% +and what I'm going to do is shoot light +not quite radial what I'm going to do is + + align:start position:0% +not quite radial what I'm going to do is + + + align:start position:0% +not quite radial what I'm going to do is +I'm gonna have sort of an array of laser + + align:start position:0% +I'm gonna have sort of an array of laser + + + align:start position:0% +I'm gonna have sort of an array of laser +beams that kind of come up here and an + + align:start position:0% +beams that kind of come up here and an + + + align:start position:0% +beams that kind of come up here and an +array of laser beams and I'm gonna shoot + + align:start position:0% +array of laser beams and I'm gonna shoot + + + align:start position:0% +array of laser beams and I'm gonna shoot +them towards this this black hole okay + + align:start position:0% +them towards this this black hole okay + + + align:start position:0% +them towards this this black hole okay +and what I'm gonna do is I'm gonna + + align:start position:0% +and what I'm gonna do is I'm gonna + + + align:start position:0% +and what I'm gonna do is I'm gonna +offset the laser beams by a distance B + + align:start position:0% + + + + align:start position:0% + +and I'm gonna fire it straight towards + + align:start position:0% +and I'm gonna fire it straight towards + + + align:start position:0% +and I'm gonna fire it straight towards +this thing okay go through sort of a + + align:start position:0% +this thing okay go through sort of a + + + align:start position:0% +this thing okay go through sort of a +careful definition of what angular + + align:start position:0% +careful definition of what angular + + + align:start position:0% +careful definition of what angular +momentum means and you'll see that that + + align:start position:0% +momentum means and you'll see that that + + + align:start position:0% +momentum means and you'll see that that +definition of of impact parameter gives + + align:start position:0% +definition of of impact parameter gives + + + align:start position:0% +definition of of impact parameter gives +you a very nice sense of the energy + + align:start position:0% +you a very nice sense of the energy + + + align:start position:0% +you a very nice sense of the energy +associate with the trajectory of this + + align:start position:0% +associate with the trajectory of this + + + align:start position:0% +associate with the trajectory of this +beam and a notion of angular momentum + + align:start position:0% +beam and a notion of angular momentum + + + align:start position:0% +beam and a notion of angular momentum +associate with this okay so let's flip + + align:start position:0% +associate with this okay so let's flip + + + align:start position:0% +associate with this okay so let's flip +back and forth between a couple of + + align:start position:0% +back and forth between a couple of + + + align:start position:0% +back and forth between a couple of +different boards here there are three + + align:start position:0% +different boards here there are three + + + align:start position:0% +different boards here there are three +cases that are interesting + + align:start position:0% + + + + align:start position:0% + +suppose B is small particular suppose I + + align:start position:0% +suppose B is small particular suppose I + + + align:start position:0% +suppose B is small particular suppose I +have B less than three root three G M + + align:start position:0% +have B less than three root three G M + + + align:start position:0% +have B less than three root three G M +okay so I start over here let's take the + + align:start position:0% +okay so I start over here let's take the + + + align:start position:0% +okay so I start over here let's take the +limit would it be equal zero + + align:start position:0% +limit would it be equal zero + + + align:start position:0% +limit would it be equal zero +well if B equals zero this guy just goes + + align:start position:0% +well if B equals zero this guy just goes + + + align:start position:0% +well if B equals zero this guy just goes +zoom straight into the black hole as + + align:start position:0% +zoom straight into the black hole as + + + align:start position:0% +zoom straight into the black hole as +long as it is anything less than three + + align:start position:0% +long as it is anything less than three + + + align:start position:0% +long as it is anything less than three +root three GM what will happen is when I + + align:start position:0% +root three GM what will happen is when I + + + align:start position:0% +root three GM what will happen is when I +shoot this thing in it goes in and it + + align:start position:0% +shoot this thing in it goes in and it + + + align:start position:0% +shoot this thing in it goes in and it +bends perhaps but it ends up going into + + align:start position:0% +bends perhaps but it ends up going into + + + align:start position:0% +bends perhaps but it ends up going into +the black hole let's look at this in the + + align:start position:0% +the black hole let's look at this in the + + + align:start position:0% +the black hole let's look at this in the +context of the equation of motion the + + align:start position:0% +context of the equation of motion the + + + align:start position:0% +context of the equation of motion the +potential and the impact parameter if B + + align:start position:0% +potential and the impact parameter if B + + + align:start position:0% +potential and the impact parameter if B +is less than one over three root three + + align:start position:0% +is less than one over three root three + + + align:start position:0% +is less than one over three root three +GM then 1 over B squared will be higher + + align:start position:0% +GM then 1 over B squared will be higher + + + align:start position:0% +GM then 1 over B squared will be higher +than this peak and this thing is just + + align:start position:0% +than this peak and this thing is just + + + align:start position:0% +than this peak and this thing is just +gonna be it's gonna go right over the + + align:start position:0% +gonna be it's gonna go right over the + + + align:start position:0% +gonna be it's gonna go right over the +top of the peak and it shoots into small + + align:start position:0% +top of the peak and it shoots into small + + + align:start position:0% +top of the peak and it shoots into small +radius okay remember L and D are + + align:start position:0% +radius okay remember L and D are + + + align:start position:0% +radius okay remember L and D are +constants of the motion so that B is a + + align:start position:0% +constants of the motion so that B is a + + + align:start position:0% +constants of the motion so that B is a +parameter that defines this this light + + align:start position:0% +parameter that defines this this light + + + align:start position:0% +parameter that defines this this light +for the entire trajectory 1 over B + + align:start position:0% +for the entire trajectory 1 over B + + + align:start position:0% +for the entire trajectory 1 over B +squared it's less than V Foat everywhere + + align:start position:0% +squared it's less than V Foat everywhere + + + align:start position:0% +squared it's less than V Foat everywhere +sue B greater than beef V fo everywhere + + align:start position:0% +sue B greater than beef V fo everywhere + + + align:start position:0% +sue B greater than beef V fo everywhere +to run a crucial typo and as such it + + align:start position:0% +to run a crucial typo and as such it + + + align:start position:0% +to run a crucial typo and as such it +shoots the light rain goes right over + + align:start position:0% +shoots the light rain goes right over + + + align:start position:0% +shoots the light rain goes right over +the peak + + align:start position:0% + + + + align:start position:0% + +into the black hole eventually grinds up + + align:start position:0% +into the black hole eventually grinds up + + + align:start position:0% +into the black hole eventually grinds up +at R equals zero if B is greater than + + align:start position:0% + + + + align:start position:0% + +three root three GM then one over B + + align:start position:0% +three root three GM then one over B + + + align:start position:0% +three root three GM then one over B +squared is less than V float at the peak + + align:start position:0% + + + + align:start position:0% + +this corresponds in this drawing to a + + align:start position:0% +this corresponds in this drawing to a + + + align:start position:0% +this corresponds in this drawing to a +beam of light that follows a trajectory + + align:start position:0% +beam of light that follows a trajectory + + + align:start position:0% +beam of light that follows a trajectory +that kind of comes in here at this point + + align:start position:0% +that kind of comes in here at this point + + + align:start position:0% +that kind of comes in here at this point +DRD tau if we were to continue going to + + align:start position:0% +DRD tau if we were to continue going to + + + align:start position:0% +DRD tau if we were to continue going to +smaller radii it would become imaginary + + align:start position:0% +smaller radii it would become imaginary + + + align:start position:0% +smaller radii it would become imaginary +that's not allowed so it switches + + align:start position:0% +that's not allowed so it switches + + + align:start position:0% +that's not allowed so it switches +direction and work trundles right back + + align:start position:0% +direction and work trundles right back + + + align:start position:0% +direction and work trundles right back +out to infinity on this diagram that + + align:start position:0% +out to infinity on this diagram that + + + align:start position:0% +out to infinity on this diagram that +corresponds to a light ray that's + + align:start position:0% +corresponds to a light ray that's + + + align:start position:0% +corresponds to a light ray that's +perhaps out here and this guy comes in + + align:start position:0% +perhaps out here and this guy comes in + + + align:start position:0% +perhaps out here and this guy comes in +maybe gets bent by the gravity a little + + align:start position:0% +maybe gets bent by the gravity a little + + + align:start position:0% +maybe gets bent by the gravity a little +bit and then just you shoots back off to + + align:start position:0% +bit and then just you shoots back off to + + + align:start position:0% +bit and then just you shoots back off to +infinity + + align:start position:0% +infinity + + + align:start position:0% +infinity +the critical point B equals 3 GM right + + align:start position:0% +the critical point B equals 3 GM right + + + align:start position:0% +the critical point B equals 3 GM right +where the impact parameter hits the peak + + align:start position:0% + + + + align:start position:0% + +so what happens in this plot is this guy + + align:start position:0% +so what happens in this plot is this guy + + + align:start position:0% +so what happens in this plot is this guy +comes in + + align:start position:0% + + + + align:start position:0% + +hits the peak and just sits there + + align:start position:0% +hits the peak and just sits there + + + align:start position:0% +hits the peak and just sits there +forever + + align:start position:0% +forever + + + align:start position:0% +forever +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +you get a little bit more of a physical + + align:start position:0% +you get a little bit more of a physical + + + align:start position:0% +you get a little bit more of a physical +sense as to what's going on by thinking + + align:start position:0% +sense as to what's going on by thinking + + + align:start position:0% +sense as to what's going on by thinking +about it here this guy comes in pitch + + align:start position:0% +about it here this guy comes in pitch + + + align:start position:0% +about it here this guy comes in pitch +this and then just whirls around and + + align:start position:0% + + + + align:start position:0% + +lies on what we call the photon orbit + + align:start position:0% +lies on what we call the photon orbit + + + align:start position:0% +lies on what we call the photon orbit +what's the rate of that photon orbit R + + align:start position:0% +what's the rate of that photon orbit R + + + align:start position:0% +what's the rate of that photon orbit R +equals 3 GM now astrophysically a more + + align:start position:0% +equals 3 GM now astrophysically a more + + + align:start position:0% +equals 3 GM now astrophysically a more +interesting situation is imagine you had + + align:start position:0% +interesting situation is imagine you had + + + align:start position:0% +interesting situation is imagine you had +some source of light that dumps a lot of + + align:start position:0% +some source of light that dumps a lot of + + + align:start position:0% +some source of light that dumps a lot of +photons in the vicinity of a black hole + + align:start position:0% +photons in the vicinity of a black hole + + + align:start position:0% +photons in the vicinity of a black hole +some of those photons are going to tend + + align:start position:0% +some of those photons are going to tend + + + align:start position:0% +some of those photons are going to tend +to you know some of them are gonna go + + align:start position:0% +to you know some of them are gonna go + + + align:start position:0% +to you know some of them are gonna go +into the black hole some are gonna + + align:start position:0% +into the black hole some are gonna + + + align:start position:0% +into the black hole some are gonna +scatter a little bit and shoot off to + + align:start position:0% +scatter a little bit and shoot off to + + + align:start position:0% +scatter a little bit and shoot off to +infinity but if you imagine that there + + align:start position:0% +infinity but if you imagine that there + + + align:start position:0% +infinity but if you imagine that there +will be some population of them that + + align:start position:0% +will be some population of them that + + + align:start position:0% +will be some population of them that +gets stuck right on the R equals 3 GM + + align:start position:0% +gets stuck right on the R equals 3 GM + + + align:start position:0% +gets stuck right on the R equals 3 GM +orbit now that is an unstable orbit and + + align:start position:0% +orbit now that is an unstable orbit and + + + align:start position:0% +orbit now that is an unstable orbit and +in fact if you look at it what you find + + align:start position:0% +in fact if you look at it what you find + + + align:start position:0% +in fact if you look at it what you find +is that your typical typical photon is + + align:start position:0% +is that your typical typical photon is + + + align:start position:0% +is that your typical typical photon is +likely to whirl around a bunch of times + + align:start position:0% +likely to whirl around a bunch of times + + + align:start position:0% +likely to whirl around a bunch of times +and then you know if it's not precisely + + align:start position:0% +and then you know if it's not precisely + + + align:start position:0% +and then you know if it's not precisely +at 3 GM but it's 3.0 ooo-ooo-ooo-ooo 1 + + align:start position:0% +at 3 GM but it's 3.0 ooo-ooo-ooo-ooo 1 + + + align:start position:0% +at 3 GM but it's 3.0 ooo-ooo-ooo-ooo 1 +GM in a whirl around maybe 10 or 15 + + align:start position:0% +GM in a whirl around maybe 10 or 15 + + + align:start position:0% +GM in a whirl around maybe 10 or 15 +times and then it'll go off to infinity + + align:start position:0% +times and then it'll go off to infinity + + + align:start position:0% +times and then it'll go off to infinity +so we actually expect is if we have an + + align:start position:0% +so we actually expect is if we have an + + + align:start position:0% +so we actually expect is if we have an +object that is illuminated like this + + align:start position:0% +object that is illuminated like this + + + align:start position:0% +object that is illuminated like this +then we will actually see these things + + align:start position:0% +then we will actually see these things + + + align:start position:0% +then we will actually see these things +come out here and we will see it so bear + + align:start position:0% +come out here and we will see it so bear + + + align:start position:0% +come out here and we will see it so bear +in mind this is circularly this is + + align:start position:0% +in mind this is circularly this is + + + align:start position:0% +in mind this is circularly this is +symmetric so take this and rotate around + + align:start position:0% +symmetric so take this and rotate around + + + align:start position:0% +symmetric so take this and rotate around +a symmetry axis we expect to see a ring + + align:start position:0% + + + + align:start position:0% + +whose radius is twice the critical + + align:start position:0% +whose radius is twice the critical + + + align:start position:0% +whose radius is twice the critical +impact parameter so it would have a + + align:start position:0% +impact parameter so it would have a + + + align:start position:0% +impact parameter so it would have a +diameter + + align:start position:0% +diameter + + + align:start position:0% +diameter +of 6 root 3 GM it would be essentially a + + align:start position:0% +of 6 root 3 GM it would be essentially a + + + align:start position:0% +of 6 root 3 GM it would be essentially a +ring or a circle of radius 3 root 3 GM + + align:start position:0% +ring or a circle of radius 3 root 3 GM + + + align:start position:0% +ring or a circle of radius 3 root 3 GM +this is in fact what the event horizon + + align:start position:0% +this is in fact what the event horizon + + + align:start position:0% +this is in fact what the event horizon +telescope measured so last year when I + + align:start position:0% +telescope measured so last year when I + + + align:start position:0% +telescope measured so last year when I +was lecturing this class this was + + align:start position:0% +was lecturing this class this was + + + align:start position:0% +was lecturing this class this was +announced almost I mean they they timed + + align:start position:0% +announced almost I mean they they timed + + + align:start position:0% +announced almost I mean they they timed +it well they put a secrete time that to + + align:start position:0% +it well they put a secrete time that to + + + align:start position:0% +it well they put a secrete time that to +about 2 or 3 lectures before I I + + align:start position:0% +about 2 or 3 lectures before I I + + + align:start position:0% +about 2 or 3 lectures before I I +discussed this this aspect of black + + align:start position:0% +discussed this this aspect of black + + + align:start position:0% +discussed this this aspect of black +holes so that was thank you event + + align:start position:0% +holes so that was thank you event + + + align:start position:0% +holes so that was thank you event +horizon telescope that was very nice of + + align:start position:0% +horizon telescope that was very nice of + + + align:start position:0% +horizon telescope that was very nice of +them and you know of course we don't + + align:start position:0% +them and you know of course we don't + + + align:start position:0% +them and you know of course we don't +expect so Schwarzschild black holes are + + align:start position:0% +expect so Schwarzschild black holes are + + + align:start position:0% +expect so Schwarzschild black holes are +probably a mathematical curiosity + + align:start position:0% +probably a mathematical curiosity + + + align:start position:0% +probably a mathematical curiosity +objects in the real universe all rotate + + align:start position:0% +objects in the real universe all rotate + + + align:start position:0% +objects in the real universe all rotate +we expect curve to be the generic + + align:start position:0% +we expect curve to be the generic + + + align:start position:0% +we expect curve to be the generic +solution and so there's a fair amount of + + align:start position:0% +solution and so there's a fair amount of + + + align:start position:0% +solution and so there's a fair amount of +work that goes into how do you correct + + align:start position:0% +work that goes into how do you correct + + + align:start position:0% +work that goes into how do you correct +this to do so doing this for Schwartz + + align:start position:0% +this to do so doing this for Schwartz + + + align:start position:0% +this to do so doing this for Schwartz +shield is because of spherical symmetry + + align:start position:0% +shield is because of spherical symmetry + + + align:start position:0% +shield is because of spherical symmetry +it's beautiful and it's simple occurs a + + align:start position:0% +it's beautiful and it's simple occurs a + + + align:start position:0% +it's beautiful and it's simple occurs a +little bit more complicated but you know + + align:start position:0% +little bit more complicated but you know + + + align:start position:0% +little bit more complicated but you know +it's a problem that can be solved and a + + align:start position:0% +it's a problem that can be solved and a + + + align:start position:0% +it's a problem that can be solved and a +lot of very smart people spend a lot of + + align:start position:0% +lot of very smart people spend a lot of + + + align:start position:0% +lot of very smart people spend a lot of +time doing this to sort of map out what + + align:start position:0% +time doing this to sort of map out what + + + align:start position:0% +time doing this to sort of map out what +the shadow of the black hole looks like + + align:start position:0% +the shadow of the black hole looks like + + + align:start position:0% +the shadow of the black hole looks like +what this ring would look like in the + + align:start position:0% +what this ring would look like in the + + + align:start position:0% +what this ring would look like in the +case of light coming off of a of a + + align:start position:0% +case of light coming off of a of a + + + align:start position:0% +case of light coming off of a of a +spinning black hole so that's it this is + + align:start position:0% +spinning black hole so that's it this is + + + align:start position:0% +spinning black hole so that's it this is +all that I'm going to present for 8 962 + + align:start position:0% +all that I'm going to present for 8 962 + + + align:start position:0% +all that I'm going to present for 8 962 +in the spring of 2020 semester so to + + align:start position:0% +in the spring of 2020 semester so to + + + align:start position:0% +in the spring of 2020 semester so to +everyone as you are scattered around the + + align:start position:0% +everyone as you are scattered around the + + + align:start position:0% +everyone as you are scattered around the +world attempting to sort of stay + + align:start position:0% +world attempting to sort of stay + + + align:start position:0% +world attempting to sort of stay +connected to physics and your friends + + align:start position:0% +connected to physics and your friends + + + align:start position:0% +connected to physics and your friends +and your classwork I wish you good + + align:start position:0% +and your classwork I wish you good + + + align:start position:0% +and your classwork I wish you good +health + + align:start position:0% +health + + + align:start position:0% +health +and I hope to see you again at a time + + align:start position:0% +and I hope to see you again at a time + + + align:start position:0% +and I hope to see you again at a time +when the world is a little less crazy in + + align:start position:0% +when the world is a little less crazy in + + + align:start position:0% +when the world is a little less crazy in +the meantime enjoy a little beautiful + + align:start position:0% +the meantime enjoy a little beautiful + + + align:start position:0% +the meantime enjoy a little beautiful +black holes \ No newline at end of file diff --git a/aYg2je06Cpg.txt b/aYg2je06Cpg.txt new file mode 100644 index 0000000000000000000000000000000000000000..8ade99e70980570dcef6748d0670c6f7ac2ccb95 --- /dev/null +++ b/aYg2je06Cpg.txt @@ -0,0 +1,1131 @@ +align:start position:0% + +let us now discuss in some more detail + + align:start position:0% +let us now discuss in some more detail + + + align:start position:0% +let us now discuss in some more detail +what it takes to carry out Bayesian + + align:start position:0% +what it takes to carry out Bayesian + + + align:start position:0% +what it takes to carry out Bayesian +inference when both random variables are + + align:start position:0% +inference when both random variables are + + + align:start position:0% +inference when both random variables are +discrete the unknown parameter theta is + + align:start position:0% +discrete the unknown parameter theta is + + + align:start position:0% +discrete the unknown parameter theta is +a random variable that takes values in a + + align:start position:0% +a random variable that takes values in a + + + align:start position:0% +a random variable that takes values in a +discrete set and we can think of these + + align:start position:0% +discrete set and we can think of these + + + align:start position:0% +discrete set and we can think of these +values as alternative hypothesis in this + + align:start position:0% +values as alternative hypothesis in this + + + align:start position:0% +values as alternative hypothesis in this +case we know how to do inference we have + + align:start position:0% +case we know how to do inference we have + + + align:start position:0% +case we know how to do inference we have +in our hands the Bayes rule and we have + + align:start position:0% +in our hands the Bayes rule and we have + + + align:start position:0% +in our hands the Bayes rule and we have +seen plenty of examples so instead of + + align:start position:0% +seen plenty of examples so instead of + + + align:start position:0% +seen plenty of examples so instead of +going through one more example in detail + + align:start position:0% +going through one more example in detail + + + align:start position:0% +going through one more example in detail +let us assume that we have a model that + + align:start position:0% +let us assume that we have a model that + + + align:start position:0% +let us assume that we have a model that +we have observed the value of x and that + + align:start position:0% +we have observed the value of x and that + + + align:start position:0% +we have observed the value of x and that +we have already determined the + + align:start position:0% +we have already determined the + + + align:start position:0% +we have already determined the +conditional pmf of the random variable + + align:start position:0% +conditional pmf of the random variable + + + align:start position:0% +conditional pmf of the random variable +theta as a concrete example suppose that + + align:start position:0% +theta as a concrete example suppose that + + + align:start position:0% +theta as a concrete example suppose that +theta can take values 1 2 or 3 we have + + align:start position:0% +theta can take values 1 2 or 3 we have + + + align:start position:0% +theta can take values 1 2 or 3 we have +obtained our observation and the + + align:start position:0% +obtained our observation and the + + + align:start position:0% +obtained our observation and the +conditional pmf takes this form we could + + align:start position:0% +conditional pmf takes this form we could + + + align:start position:0% +conditional pmf takes this form we could +stop at this point or we could continue + + align:start position:0% +stop at this point or we could continue + + + align:start position:0% +stop at this point or we could continue +by asking for a specific estimate of + + align:start position:0% +by asking for a specific estimate of + + + align:start position:0% +by asking for a specific estimate of +theta our best guess as what theta is + + align:start position:0% +theta our best guess as what theta is + + + align:start position:0% +theta our best guess as what theta is +one way of coming up with an estimate is + + align:start position:0% +one way of coming up with an estimate is + + + align:start position:0% +one way of coming up with an estimate is +to use the maximum a posteriori + + align:start position:0% +to use the maximum a posteriori + + + align:start position:0% +to use the maximum a posteriori +probability rule which looks for that + + align:start position:0% +probability rule which looks for that + + + align:start position:0% +probability rule which looks for that +value of theta that has the largest + + align:start position:0% +value of theta that has the largest + + + align:start position:0% +value of theta that has the largest +posterior or conditional probability in + + align:start position:0% +posterior or conditional probability in + + + align:start position:0% +posterior or conditional probability in +this example it is this value so our + + align:start position:0% +this example it is this value so our + + + align:start position:0% +this example it is this value so our +estimate is going to be equal to 2 an + + align:start position:0% +estimate is going to be equal to 2 an + + + align:start position:0% +estimate is going to be equal to 2 an +alternative way of coming up with an + + align:start position:0% +alternative way of coming up with an + + + align:start position:0% +alternative way of coming up with an +estimate could be the LMS rule which + + align:start position:0% +estimate could be the LMS rule which + + + align:start position:0% +estimate could be the LMS rule which +calculates an estimate equal to the + + align:start position:0% +calculates an estimate equal to the + + + align:start position:0% +calculates an estimate equal to the +conditional expectation of the unknown + + align:start position:0% +conditional expectation of the unknown + + + align:start position:0% +conditional expectation of the unknown +parameter given the observation that we + + align:start position:0% +parameter given the observation that we + + + align:start position:0% +parameter given the observation that we +have made this is just the mean of this + + align:start position:0% +have made this is just the mean of this + + + align:start position:0% +have made this is just the mean of this +conditional distribution in this example + + align:start position:0% +conditional distribution in this example + + + align:start position:0% +conditional distribution in this example +it would fall somewhere around here and + + align:start position:0% +it would fall somewhere around here and + + + align:start position:0% +it would fall somewhere around here and +the numerical value as you can check is + + align:start position:0% +the numerical value as you can check is + + + align:start position:0% +the numerical value as you can check is +equal to 2 point 2 next we may be + + align:start position:0% +equal to 2 point 2 next we may be + + + align:start position:0% +equal to 2 point 2 next we may be +interested in how good a certain + + align:start position:0% +interested in how good a certain + + + align:start position:0% +interested in how good a certain +estimate is and for the case where we + + align:start position:0% +estimate is and for the case where we + + + align:start position:0% +estimate is and for the case where we +interpret the values of theta as + + align:start position:0% +interpret the values of theta as + + + align:start position:0% +interpret the values of theta as +hypotheses a relevant criterion is the + + align:start position:0% +hypotheses a relevant criterion is the + + + align:start position:0% +hypotheses a relevant criterion is the +probability of error in this case + + align:start position:0% +probability of error in this case + + + align:start position:0% +probability of error in this case +because we already have some data + + align:start position:0% +because we already have some data + + + align:start position:0% +because we already have some data +available in our + + align:start position:0% +available in our + + + align:start position:0% +available in our +and were called to make an estimate what + + align:start position:0% +and were called to make an estimate what + + + align:start position:0% +and were called to make an estimate what +we care about is the conditional + + align:start position:0% +we care about is the conditional + + + align:start position:0% +we care about is the conditional +probability given the information that + + align:start position:0% +probability given the information that + + + align:start position:0% +probability given the information that +we have that we're making an error + + align:start position:0% +we have that we're making an error + + + align:start position:0% +we have that we're making an error +making an error means the following we + + align:start position:0% +making an error means the following we + + + align:start position:0% +making an error means the following we +have the observation the value of the + + align:start position:0% +have the observation the value of the + + + align:start position:0% +have the observation the value of the +estimate has been determined it is now a + + align:start position:0% +estimate has been determined it is now a + + + align:start position:0% +estimate has been determined it is now a +number and that's why we write it with a + + align:start position:0% +number and that's why we write it with a + + + align:start position:0% +number and that's why we write it with a +lowercase theta hat but the parameter is + + align:start position:0% +lowercase theta hat but the parameter is + + + align:start position:0% +lowercase theta hat but the parameter is +still unknown we don't know what it is + + align:start position:0% +still unknown we don't know what it is + + + align:start position:0% +still unknown we don't know what it is +it is described by this distribution and + + align:start position:0% +it is described by this distribution and + + + align:start position:0% +it is described by this distribution and +there is a probability that it's going + + align:start position:0% +there is a probability that it's going + + + align:start position:0% +there is a probability that it's going +to be different from our estimate what + + align:start position:0% +to be different from our estimate what + + + align:start position:0% +to be different from our estimate what +is this probability it depends on how we + + align:start position:0% +is this probability it depends on how we + + + align:start position:0% +is this probability it depends on how we +construct the estimates if in this + + align:start position:0% +construct the estimates if in this + + + align:start position:0% +construct the estimates if in this +example we use the map rule and we make + + align:start position:0% +example we use the map rule and we make + + + align:start position:0% +example we use the map rule and we make +an estimate of to the risk probability + + align:start position:0% +an estimate of to the risk probability + + + align:start position:0% +an estimate of to the risk probability +point six that the true value of theta + + align:start position:0% +point six that the true value of theta + + + align:start position:0% +point six that the true value of theta +is also equal to 2 and we are fine but + + align:start position:0% +is also equal to 2 and we are fine but + + + align:start position:0% +is also equal to 2 and we are fine but +there is a remaining probability of 0.4 + + align:start position:0% +there is a remaining probability of 0.4 + + + align:start position:0% +there is a remaining probability of 0.4 +that the true value of theta is + + align:start position:0% +that the true value of theta is + + + align:start position:0% +that the true value of theta is +different than our estimate so there's + + align:start position:0% +different than our estimate so there's + + + align:start position:0% +different than our estimate so there's +probability point 4 of having made a + + align:start position:0% +probability point 4 of having made a + + + align:start position:0% +probability point 4 of having made a +mistake if instead of an estimate equal + + align:start position:0% +mistake if instead of an estimate equal + + + align:start position:0% +mistake if instead of an estimate equal +to 2 we had chosen an estimate equal to + + align:start position:0% +to 2 we had chosen an estimate equal to + + + align:start position:0% +to 2 we had chosen an estimate equal to +3 then the true parameter would be equal + + align:start position:0% +3 then the true parameter would be equal + + + align:start position:0% +3 then the true parameter would be equal +to our estimate with probability point 3 + + align:start position:0% +to our estimate with probability point 3 + + + align:start position:0% +to our estimate with probability point 3 +but we would have made an error with + + align:start position:0% +but we would have made an error with + + + align:start position:0% +but we would have made an error with +probability point 7 which would be a + + align:start position:0% +probability point 7 which would be a + + + align:start position:0% +probability point 7 which would be a +bigger probability of error more + + align:start position:0% +bigger probability of error more + + + align:start position:0% +bigger probability of error more +generally the probability of error of a + + align:start position:0% +generally the probability of error of a + + + align:start position:0% +generally the probability of error of a +particular estimate is the sum of the + + align:start position:0% +particular estimate is the sum of the + + + align:start position:0% +particular estimate is the sum of the +probabilities of the other values of + + align:start position:0% +probabilities of the other values of + + + align:start position:0% +probabilities of the other values of +theta and if we want to keep the + + align:start position:0% +theta and if we want to keep the + + + align:start position:0% +theta and if we want to keep the +probability of error small we want to + + align:start position:0% +probability of error small we want to + + + align:start position:0% +probability of error small we want to +keep the sum of the probabilities of the + + align:start position:0% +keep the sum of the probabilities of the + + + align:start position:0% +keep the sum of the probabilities of the +other values small which means we want + + align:start position:0% +other values small which means we want + + + align:start position:0% +other values small which means we want +to pick an estimate for which its own + + align:start position:0% +to pick an estimate for which its own + + + align:start position:0% +to pick an estimate for which its own +probability is large and so by that + + align:start position:0% +probability is large and so by that + + + align:start position:0% +probability is large and so by that +argument we see that the way to achieve + + align:start position:0% +argument we see that the way to achieve + + + align:start position:0% +argument we see that the way to achieve +the smallest possible probability of + + align:start position:0% +the smallest possible probability of + + + align:start position:0% +the smallest possible probability of +error is to employ the map rule and this + + align:start position:0% +error is to employ the map rule and this + + + align:start position:0% +error is to employ the map rule and this +is a very important property of the map + + align:start position:0% +is a very important property of the map + + + align:start position:0% +is a very important property of the map +rule now this is the conditional + + align:start position:0% +rule now this is the conditional + + + align:start position:0% +rule now this is the conditional +probability of error given that we + + align:start position:0% +probability of error given that we + + + align:start position:0% +probability of error given that we +already have data in our hands but more + + align:start position:0% +already have data in our hands but more + + + align:start position:0% +already have data in our hands but more +generally we may want to compare + + align:start position:0% +generally we may want to compare + + + align:start position:0% +generally we may want to compare +estimators or talk about their + + align:start position:0% +estimators or talk about their + + + align:start position:0% +estimators or talk about their +performance + + align:start position:0% +performance + + + align:start position:0% +performance +in terms of their overall probability of + + align:start position:0% +in terms of their overall probability of + + + align:start position:0% +in terms of their overall probability of +terror we're designing a decision-making + + align:start position:0% +terror we're designing a decision-making + + + align:start position:0% +terror we're designing a decision-making +system that's going to process data and + + align:start position:0% +system that's going to process data and + + + align:start position:0% +system that's going to process data and +making decisions in order to say how + + align:start position:0% +making decisions in order to say how + + + align:start position:0% +making decisions in order to say how +good our system is we want to say that + + align:start position:0% +good our system is we want to say that + + + align:start position:0% +good our system is we want to say that +overall whenever you use the system + + align:start position:0% +overall whenever you use the system + + + align:start position:0% +overall whenever you use the system +there's going to be some random + + align:start position:0% +there's going to be some random + + + align:start position:0% +there's going to be some random +parameter there's going to be some value + + align:start position:0% +parameter there's going to be some value + + + align:start position:0% +parameter there's going to be some value +of the estimate and we want to know + + align:start position:0% +of the estimate and we want to know + + + align:start position:0% +of the estimate and we want to know +what's the probability that these two + + align:start position:0% +what's the probability that these two + + + align:start position:0% +what's the probability that these two +will be different we can calculate this + + align:start position:0% +will be different we can calculate this + + + align:start position:0% +will be different we can calculate this +overall probability of error by using + + align:start position:0% +overall probability of error by using + + + align:start position:0% +overall probability of error by using +the total probability theorem and the + + align:start position:0% +the total probability theorem and the + + + align:start position:0% +the total probability theorem and the +conditional probabilities of error as + + align:start position:0% +conditional probabilities of error as + + + align:start position:0% +conditional probabilities of error as +follows we condition on the value of x + + align:start position:0% +follows we condition on the value of x + + + align:start position:0% +follows we condition on the value of x +for any possible value of x we have a + + align:start position:0% +for any possible value of x we have a + + + align:start position:0% +for any possible value of x we have a +conditional probability of Terror and + + align:start position:0% +conditional probability of Terror and + + + align:start position:0% +conditional probability of Terror and +then we take a weighted average of these + + align:start position:0% +then we take a weighted average of these + + + align:start position:0% +then we take a weighted average of these +conditional probabilities of error there + + align:start position:0% +conditional probabilities of error there + + + align:start position:0% +conditional probabilities of error there +is also an alternative way of using the + + align:start position:0% +is also an alternative way of using the + + + align:start position:0% +is also an alternative way of using the +total probability theorem which would be + + align:start position:0% +total probability theorem which would be + + + align:start position:0% +total probability theorem which would be +to first condition on theta and + + align:start position:0% +to first condition on theta and + + + align:start position:0% +to first condition on theta and +calculate the conditional probability of + + align:start position:0% +calculate the conditional probability of + + + align:start position:0% +calculate the conditional probability of +error for a given choice of this unknown + + align:start position:0% +error for a given choice of this unknown + + + align:start position:0% +error for a given choice of this unknown +parameter and both of these formulas can + + align:start position:0% +parameter and both of these formulas can + + + align:start position:0% +parameter and both of these formulas can +be used which one of the two is more + + align:start position:0% +be used which one of the two is more + + + align:start position:0% +be used which one of the two is more +convenient really depends on the + + align:start position:0% +convenient really depends on the + + + align:start position:0% +convenient really depends on the +specifics of the problem finally we + + align:start position:0% +specifics of the problem finally we + + + align:start position:0% +specifics of the problem finally we +would like to make an important + + align:start position:0% +would like to make an important + + + align:start position:0% +would like to make an important +observation we argued that for any + + align:start position:0% +observation we argued that for any + + + align:start position:0% +observation we argued that for any +particular choice of an observation the + + align:start position:0% +particular choice of an observation the + + + align:start position:0% +particular choice of an observation the +map rule achieves the smallest possible + + align:start position:0% +map rule achieves the smallest possible + + + align:start position:0% +map rule achieves the smallest possible +probability of error so under the map + + align:start position:0% +probability of error so under the map + + + align:start position:0% +probability of error so under the map +rule this term is as small as possible + + align:start position:0% +rule this term is as small as possible + + + align:start position:0% +rule this term is as small as possible +for any given value of the random + + align:start position:0% +for any given value of the random + + + align:start position:0% +for any given value of the random +variable capital X since each term of + + align:start position:0% +variable capital X since each term of + + + align:start position:0% +variable capital X since each term of +this sum is as small as possible under + + align:start position:0% +this sum is as small as possible under + + + align:start position:0% +this sum is as small as possible under +the map rule it means that the overall + + align:start position:0% +the map rule it means that the overall + + + align:start position:0% +the map rule it means that the overall +sum will also be as small as possible + + align:start position:0% +sum will also be as small as possible + + + align:start position:0% +sum will also be as small as possible +and this means that the overall + + align:start position:0% +and this means that the overall + + + align:start position:0% +and this means that the overall +probability of error is also smallest + + align:start position:0% +probability of error is also smallest + + + align:start position:0% +probability of error is also smallest +under the map + + align:start position:0% +under the map + + + align:start position:0% +under the map +in this sense the map rule is the + + align:start position:0% +in this sense the map rule is the + + + align:start position:0% +in this sense the map rule is the +optimal way of coming up with estimates + + align:start position:0% +optimal way of coming up with estimates + + + align:start position:0% +optimal way of coming up with estimates +in the hypothesis testing context where + + align:start position:0% +in the hypothesis testing context where + + + align:start position:0% +in the hypothesis testing context where +we want to minimize the probability of + + align:start position:0% +we want to minimize the probability of + + + align:start position:0% +we want to minimize the probability of +error \ No newline at end of file diff --git a/b7SDngGtNDs.txt b/b7SDngGtNDs.txt new file mode 100644 index 0000000000000000000000000000000000000000..378f9eee2db33dcb300504ab01cdfa82a4366ad2 --- /dev/null +++ b/b7SDngGtNDs.txt @@ -0,0 +1,521 @@ +The following content is +provided under a Creative + +Commons license. + +Your support will help MIT +OpenCourseWare continue to + +offer high-quality educational +resources for free. + +To make a donation or view +additional materials from + +hundreds of MIT courses, visit +MIT OpenCourseWare at + +ocw.mit.edu. + +Hi I'm Jocelyn and we're going +to go over fall 2009, the + +final exam, problem number 6. + +It says, the dipeptide shown +below is derived from alanine + +and serine. + +And I'll write up that +structure here. + +And we know it's a dipeptide +because we + +see that it has two-- + +what look like-- + +amine groups and two kind +of carboxyl groups. + +So that's an indicator that +we're dealing with a dipeptide + +not just one amino acid. + +Something to notice right off +the bat is that we're given + +the zwitterion form. + +We have the amine group at the +end here is protonated and the + +carboxylic group on the other +end is deprotonated. + +So moving to part 1. + +It asked us to indicate the +position of the peptide bond. + +Hopefully this is a pretty +straightforward task. + +We realize that the +dipeptide bond is + +what makes the dipeptide. + +It's the bond between the amine +group of one amino acid + +and the carboxyl group +of another. + +Right there. + +So circling that carbon nitrogen +bond would get you + +full credit on that part. + +Moving to part 2. + +We are asked to draw the +skeletal structure of each + +constituent amino acid as it +would be present in an aqueous + +solution of an extreme +basicity, i.e. pH + +greater than 12. + +So before even starting to write +we want to think about + +what extreme basicity means. + +Well it means that both our +amine group and our carboxylic + +acid group are going +to be deprotonated. + +So let's start with +alanine first. We + +have the central carbon. + +The amine group. + +And the carboxylic acid group. + +Now I just drew that +totally protonated. + +However we want to draw it +totally deprotonated because + +it's in basic solution. + +So I'm just going to erase +the extra hydrogens. + +And we have a deprotonated amine +group and a deprotonated + +carboxyl group. + +And that is what it would look +like in basic solution. + +Now serine is a little different +because you have a + +side group with functionality. + +It has not just carbon +and hydrogen. + +First drawing up the backbone +here, we have a central + +carbon, which has a methyl +alcohol group off of it. + +And attach the carboxylic +acid. + +And amine group on +the left here. + +So this one I drew as the +zwitterion, which would be in + +moderately or kind of neutral. + +It depends upon the +amino acid. + +But again we want to deprotonate +our amine group + +here because pH greater than 12 +will not have a protonated + +amine group. + +Now the question is, +what do we do with + +the side chain here? + +It has an H attached +to an oxygen. + +Does that come off in super +basic solution or not? + +A lot of students got +tripped up on this. + +An alcohol actually has +a pKa of about 16. + +And so it won't be deprotonated + +in an aqueous solution. + +Therefore we want to keep +this hydrogen on. + +It will not be-- + +this will not be a charged +oxygen in the basic solution + +that we were asked about. + +So now we are going to +move on to the second + +part of this problem. + +The second part asks us about +the tertiary structure of the + +length of protein +that is shown. + +I am not going to draw the whole +length of protein but + +we're going to-- + +at the four specified +locations-- + +we're going to indicate what +we would call the tertiary + +structure; or what functionality +is causing the + +tertiary structure. + +So looking at that +protein chain. + +Professor Sadoway has indicated +four different + +distinct parts of the chain. + +And the question is asking us, +at each of the four numbered + +positions name one chemical +change to the environment of + +the protein that would +destabilize the associated + +feature in the tertiary +structure. + +Explain the relevant chemistry +so it's asking us to say what + +can we do to disrupt that +tertiary structure? + +And the first thing we need to +do is figure out what the + +tertiary structure is. + +So if we look at number 1, we +see that it has two sulphur + +atoms connected together. + +So we call that a +disulfide bond. + +The second part, we see that we +have a phenyl group, so it + +has a very electron-deficient +hydrogen interacting with a + +deprotonated carboxyl +oxygen anion. + +And so we have a hydrogen bond +there and that's what's + +causing those amino acids +to be pulled together. + +So let's just say +hydrogen bond. + +At the third number we see +that we had a deprotonate + +carboxyl group and a protonated +amine group + +interacting. + +And that's not quite a hydrogen +bond but it's a + +negatively charged part of the +molecule interacting with the + +positively charged part of +a different molecule. + +And so we call that +electrostatic interaction. + +It's similar to a hydrogen +bond in that it's a + +intermolecular interaction +that's causing these molecules + +to move closer, preference +to be closer together. + +And now we come to +the fourth part. + +Which is hydrophobic +interactions. + +So we see that there +are a lot of just + +carbon hydrogen chains. + +No oxygen is around, no +amine groups around. + +Purely carbon and hydrogen. + +And because this is an aqueous +solution, those hydrophobic + +parts of the molecules will +preferentially go together and + +kind of make a little-- + +almost like an-- oil +droplet in water. + +They're trying to decrease the +amount that they experience + +the polarity of the water. + +And so the interactions +are hydrophobic. + +So now that we know what the +functionality at each of these + +points in the DNA structure are, +we can go back to what + +the question is actually asking +us, which is, how can + +we actually disrupt +these features. + +So the first one is the +disulfide bond. + +And in class Professor Sadoway +talked about how to disrupt + +the disulfide bond. + +And one of the ways +is to put extreme + +heat on to the protein. + +And that breaks the disulfide +bond and you can straighten + +out that portion of the DNA. + +This is how you straighten your +hair if it's curly or + +other types of things with +the disulfide bond. + +So heating the disulfide bond to +extreme heat will cause it + +to break and thus the protein +will lose that, that folding + +or whatever the disulfide bond +imparted to that portion of + +the protein. + +Now going on to number 2. + +We have hydrogen bonding. + +And we see that it's between a +alcohol group on a ring there + +and a carboxyl group. + +So one way to disrupt that +hydrogen bond is to make the + +carboxyl group no longer +deprotonated. + +So if we put back on the +hydrogen to that oxygen it + +will become less partially +negative. + +It will have a lower + +interaction with that hydrogen. + +And so we can say, to protonate +that carboxyl we + +want to make the solution +more acidic. + +So we can add acid. + +So the disulfide we're going +to heat, the hydrogen bond + +we're going to add acid. + +Looking at number 3 we +see that we have a + +electrostatic reaction. + +And so we want to not have that +electrostatic reaction. + +And one way to do that is to +make one of those entities not + +have a charge. + +So one way to do that would be +to reprotonate the carboxylic + +acid, just as we did in +the previous step. + +Or we could deprotonate +the amine group. + +And that would cause it to lose +its charge and thus the + +electrostatic interaction +would be weaker or gone. + +So to deprotonate the amine +group we should know that we + +want to add base. + +And the final part is, the +portion with hydrophilic + +interactions. + +And here we want to figure +out a way to make those + +hydrophobic portions of the +amino acids not hold as + +tightly together. + +And one thing we learned +about in class is + +something like soap. + +Something that has a hydrophobic +side and a + +hydrophilic side. + +And so if we put soap in with +this protein it can kind of + +stabilize the hydrophobic part +and make it stretch out a + +little bit more, not +ball up so tightly. + +So soap or detergent would be +a good answer for this one. + +And so for this question, as +long as you indicated the + +relevant chemistry, which is +specified what tertiary + +structure you were looking +at and how your suggested + +procedure would disrupt that +tertiary structure, that's + +what Professor Sadoway was +looking for and that would + +mean that you answered the +question completely. \ No newline at end of file diff --git a/cRsptYEK1G4.txt b/cRsptYEK1G4.txt new file mode 100644 index 0000000000000000000000000000000000000000..1cbd85bdeb57af351167e6a2b36f260a5981e952 --- /dev/null +++ b/cRsptYEK1G4.txt @@ -0,0 +1,1068 @@ +PROFESSOR: OK, earlier lecture +introduced the logarithm as + +the inverse function +to the exponential. + +And now it's time to do +calculus, find its derivative. + +And we spoke about other inverse +functions, and here is + +an important one: the inverse +sine function, or sometimes + +called the arc sine. + +We'll find its derivative, +too. + +OK, so what we're doing really +is sort of completing the list + +of important rules +for derivatives. + +We know about the derivative +of a sum. + +Just add the derivatives. + +f minus g, just subtract +the derivatives. + +We know the product rule and the +quotient rule, so that's + +add, subtract, multiply, +divide functions. + +And then very, very important is +the chain of functions, the + +chain rule. + +This is never to be mixed +up with that. + +You wouldn't do such a thing. + +And now we're adding +one more f inverse. + +That's today, the derivative +of the inverse. + +That will really complete +the rules. + +Out of simple functions like +exponential, sine and cosine, + +powers of x, this creates all +the rest of the functions that + +we typically use. + +OK, so let's start with the most +important of all: the f + +of x is e to the x. + +And then the inverse +function, we + +named the natural logarithm. + +And notice, remember how +I reversed the letters. + +Here, x is the input and y +is the output from the + +exponential function. + +So for the inverse function, +y is the input. + +I go backwards to x, and the +thing to remember, the one + +thing to remember, just tell +yourself x is the exponent. + +The logarithm is the exponent. + +OK, so a chain of functions +is coming here, and it's a + +perfectly terrific chain. + +This is the rule for +inverse functions. + +If I start with an x and I do +f of x, that gets me to y. + +And now I do the inverse +function, and it + +brings me back to x. + +So I really have a chain +of functions. + +The chain has a very +special result. + +And our situation is if we +know how to take the + +derivative of f, this ought to +tell us-- the chain rule-- + +how to take the derivative +of the + +inverse function, f inverse. + +Let me try it with this +all-important example. + +So which-- + +and notice also, chain +goes the other way. + +If I start with y, do the +inverse function, then + +I've reached x. + +Then f of x is y. + +Maybe before I take e to the +x, let me take the function + +that always is the +starting point. + +So practice is-- + +I'll call this example of-- + +just to remember how inverse +functions work-- + +linear functions. + +y equals ax plus b. + +That's f of x there. + +Linear. + +What's the inverse of that? + +Now the point about inverses +is I want to solve for x in + +terms of y. + +I want to get x by itself. + +So I move b to the +opposite side. + +So in the end, I want to +get x equals something. + +And how do I do that? + +I move b to the opposite side, +and then I still have ax, so I + +divide by a. + +Then I've got x by itself. + +This is the inverse. + +This is f inverse of y. + +Notice something about inverse +functions, that here we did-- + +this function f of x was +created in two steps. + +it was sort of a chain +in itself. + +The first step was +multiply by a. + +We multiply and then we add. + +What's inverse function do? + +The inverse function takes y. + +Subtracts b. + +So it does subtract first +to get y minus + +b, and then it divides. + +What's my point? + +My point is that if a function +is built in two steps, + +multiply and then add in this +nice case, the inverse + +function does the +inverse steps. + +Instead of multiplying +it divides. + +Instead of add, it subtracts. + +What it does though is +the opposite order. + +Notice the multiply was done +first, then the divide is + +last. The add was done second, +the subtract was done first. + +When you invert things, the +order-- well, you know it. + +It has to be that way. + +It's that way in life, right? + +If we're standing on the beach +and we walk to the water and + +then we swim to the dock, so +that's our function f of x + +from where we were to the dock, +then how do we get back? + +Well, wise to swim +first, right? + +You don't want to walk first. +From the dock, you swim back. + +So you swam one way at the +end, and then in the + +inverse, you swim-- + +oh, you get it. + +OK, so now I'm ready +for the real thing. + +I'll take one of those chains +and take its derivative. + +Let me take the first one. + +So the first one says that the +log of e to the x is x. + +That's-- + +The logarithm was defined +that way. + +That's what the log is. + +Let's take the derivative of +that equation, the derivative + +of both sides. + +We will be learning what's the +derivative of the log. + +That's what we don't know. + +So if I take the derivative, +well, on the right-hand side, + +I certainly get 1. + +On the left-hand side, this +is where it's interesting. + +So it's the chain rule. + +The log of something, so I +should take the derivative-- + +oh, I need a little more +space here, over here. + +The derivative of log +y, y is e to the x. + +Everybody's got that, right? + +So this is log y, and I'm taking +its derivative with + +respect to y. + +But then I have to, as the chain +rule tells me, take the + +derivative of what's inside. + +What's inside is e to the +x, so I have dy dx. + +So I put dy dx. + +And the derivative on the +right-hand side, the neat + +point here is that the +x-derivative of that is 1. + +OK, now I'm going to learn what +this is because I know + +what this is: the derivative +of dy dx, the derivative of + +the exponential. + +Well, now comes the most +important property that we use + +to construct this exponential. + +dy dx is e to the x. + +No problem, OK? + +And now, I'm going to divide +by it to get what I want-- + +almost. Almost, I say. + +Well, I've got the derivative +of log y here. + +Correct, but there's a +step to take still. + +I have to write-- + +I want a function of y. + +The log is a function of y. + +It's derivative is-- + +the answer is a function of y. + +So I have to go back +from x to y. + +But that's simple. + +e to the x is y. + +Oh! + +Look at this fantastic answer. + +The derivative of the log, the +thing we wanted, is 1 over y. + +Why do I say fantastic? + +Because out of the blue almost, +we've discovered the + +function log y, which has that +derivative 1 over y. + +And the point is this is +the minus 1 power. + +It's the only power that we +didn't produce earlier as a + +derivative. + +I have to make that point. + +You remember the very first +derivatives we knew were the + +derivatives of x to the +n-th, powers of x. + +Everybody knows that that's n +times x to the n minus 1. + +The derivative of every power +is one power below. + +With one exception. + +With one exception. + +If n is 0, so I have to +put except n equals 0. + +Well, it's true when n is 0, +so I don't mean the formula + +doesn't fail. + +What fails is when n is 0, this +right-hand side is 0, and + +I don't get the minus 1 power. + +No power of x produces the minus +1 power when I take the + +derivative. + +So that was like an open hole +in the list of derivatives. + +Nobody was giving the derivative +to be the minus 1 + +power when we were looking +at the powers of x. + +Well, here it showed up. + +Now, you'll say the +letter y's there. + +OK, that's the 25th letter +of the alphabet. + +I'm perfectly happy if you +prefer the 26th letter. + +You can write d log z dz equals +1/z if you want to. + +You can write, as you might +like to, d by dx. + +Use the 24th letter +of log x is 1/x. + +I'm perfectly OK for you to do +that, to write the x there, + +now after we got the formula. + +Up to this point, I really had +to keep x and y straight + +because I was beginning +from y is e to the x. + +That was my starting point. + +OK, so that keeping them +straight got me the derivative + +of log y as 1/y. + +End. + +Now, I'm totally happy if you +use any other letter. + +Use t if you have +things growing. + +And remember about the +logarithm now. + +We can see why it +grows so slowly. + +Because its slope is 1/y. + +Or let's look at this one, +because we're used to thinking + +of graphs with x +along the axis. + +And this is telling us that the +slope of the log curve-- + +the log curve is increasing, but +the slope is decreasing, + +getting smaller and smaller. + +As x gets very small, it's +just barely increasing. + +It does keep going on +up to infinity, + +but very, very slowly. + +And why is that? + +That's because the exponential +is going very, very quickly. + +And you remember that the one +graph is just the flip of the + +other graph, so if one is +climbing like mad, the other + +one is growing slowly. + +OK, that's the main facts, the +most important formula of + +today's lecture. + +I could-- + +do you feel like practice to +take the chain in the opposite + +direction just to see +what would happen? + +So what's the opposite +direction? + +I guess the opposite direction +is to start with-- + +which did I start with? + +I started with log of +e to the x is x. + +The opposite direction would be +to start with e to the log + +y is y, right? + +That's the same chain. + +That's the f inverse coming +before the f. + +What do I do? + +Take derivatives. + +Take the derivative +of everything, OK? + +So take the derivative, +the y-derivative. + +I get the nice thing. + +I mean, that's the fun part, +taking the derivative on the + +right-hand side. + +On the left side, a little more +work, but I know how to + +take the derivative of +e to the something. + +It's the chain rule. + +Of course it's the chain rule. + +We got a chain here. + +So the derivative of e to the +something, now you remember + +with the chain rule, is e to +that same something times the + +derivative of what's inside. + +The derivative and what's +inside is this guy: the + +derivative of log y dy. + +This is what we want to know, +the one we know, and what is e + +to the log y? + +It's sitting up there +on the line before. + +e to the log y is y. + +So this parenthesis is +just containing y. + +Bring it down. + +Set it under there, and +you have it again. + +The derivative of log y +dy is 1 over e to the + +log y, which is y. + +OK, we sort of have done more +about inverse functions than + +typical lectures might, but I +did it really because they're + +kind of not so simple. + +And yet, they're crucially +important in this situation of + +connecting exponential +with log. + +And by the way, I prefer to +start with exponential. + +The logic goes also just fine. + +In fact, some steps are a little +smoother if you start + +with a logarithm function, +define that somehow, and then + +take its inverse, which will +be the exponential. + +But for me, the exponential +is so all important. + +The logarithm is important, but +it's not in the league of + +e to the x. + +So I prefer to do it this +way to know e to the x. + +Now if you bear with me, +I'll do the other + +derivative for today. + +The other derivative +is this one. + +Can we do that? + +OK, so I want the derivative +of this arc sine + +function, all right? + +So I'm going to-- + +let me bring that. + +This side of the board is now +going to be x is the inverse + +sine of y, or it's often called +the arc sine of y. + +OK, good. + +All right. + +So again, I have a chain. + +I start with x. + +I create y. + +So y is sine x. + +So y is the sine of x, but +x is the arc sine of y. + +That's the chain. + +Start with a y. + +Do f inverse. + +Do f, and you got y +again, all right? + +Now, I'm interested in the +derivative, the derivative of + +this arc sine of y. + +I want the y-derivative. + +I'm just going to copy this +plan, but instead of e, I've + +got sines here. + +So take the y-derivative of both +sides, the y-derivative + +of both sides. + +Well, I always like that one. + +The y-derivative of this +is the chain rule. + +So I have the sine of some +inside function. + +So the derivative is the cosine +of that inside function + +times the derivative of the +inside function, which is the + +guy we want. + +OK, so I have to figure +out that thing. + +In other words, I guess I've +got to think a little bit + +about these inverse +trig functions. + +OK, so what's the story with +the inverse trig functions? + +The point will be this +is an angle. + +Ha! + +That's an angle. + +Let me draw the triangle. + +Here is my angle theta. + +Here is my sine theta. + +Here is my cos theta, and +everybody knows that now the + +hypotenuse is 1. + +So here is theta. + +OK, whoa! + +Wait a minute. + +I would love theta to +be the angle whose-- + +oh, maybe it is. + +This is the angle whose sine-- + +theta should be the angle +whose sine is y, right? + +OK, theta is the angle +whose sine is y. + +OK, let me make that happen. + +And now, tell me the other side +because I got to get a + +cosine in here somewhere. + +What is this side? + +Back to Pythagoras, the +most important fact + +about a right triangle. + +This side will be the +square root of-- + +this squared plus this squared +is 1, so this is the square + +root of 1 minus y squared. + +And that's the cosine. + +The cosine of this angle theta +is this guy divided by 1. + +We're there, and all I've used +pretty quickly was I popped up + +a triangle there. + +I named an angle theta. + +I took its sine to be y, and +I figured out what its + +cosine had to be. + +OK, so there's the theta. + +Its cosine has to be this, +and now I'm ready to + +write out the answer. + +I'm ready to write down +the answer there. + +That has a 1 equals-- + +the cosine of theta, that's this +times the derivative of + +the inverse sine. + +You see, I had to get this +expression into something-- + +I had to solve it for y. + +I had to figure out what +that quantity is as + +a function of y. + +And now I just put +this down below. + +So if I cross this out +and put it down here, + +I've got the answer. + +There is the derivative of the +arc sine function: 1 over the + +square root of 1 minus +y squared. + +OK, it's not as beautiful as +1/y, but it shows up in a lot + +of problems. As we said earlier, +sines and cosines are + +involved with repeated motion, +going around a circle, going + +up and down, going across +and back, in and out. + +And it will turn out that this +quantity, which is really + +coming from the Pythagoras, is +going to turn up, and we'll + +need to know that it's the +derivative of the arc sine. + +And may I just write down what's +the derivative of the + +arc cosine as long +as we're at it? + +And then I'm done. + +The derivative of the +arc cosine, well, + +you remember what-- + +what's the difference between +sines and cosines when we take + +derivatives? + +The cosine has a minus. + +So there'll be a minus 1 +over the square root + +of 1 minus y squared. + +That's sort of unexpected. + +This function has +this derivative. + +This function has the +same derivative but + +with a minus sign. + +That suggests that somehow if I +add those, yeah, let's just + +think about that for the +last minute here. + +That says that if I add sine +inverse y to cosine inverse y, + +their derivatives will cancel. + +So the derivative of that +sum of this one-- + +can I do a giant plus +sign there?-- + +is 0. + +The derivative of that plus the +derivative of that is a + +plus thing and a minus +thing, giving 0. + +So how could that be? + +Have you ever thought +about what functions + +have derivative 0? + +Well, actually, you have. +You know what + +functions have no slope. + +Constant functions. + +So I'm saying that it must +happen that the arc sine + +function plus the arc cosine +function is a constant. + +Then its derivative +is 0, and we are + +happy with our formulas. + +And actually, that's true. + +The arc sine function +gives me this angle. + +The arc cosine function +would give me-- + +shall I give that angle another +name like alpha? + +This one would be the theta. + +That one would be the alpha. + +And do you believe that in that +triangle theta plus alpha + +is a constant and therefore +has derivative 0? + +In fact, yes, you +know what it is. + +Theta plus alpha in a right +triangle, if I add that angle + +and that angle, I +get 90 degrees. + +A constant. + +Well, 90 degrees, but I +shouldn't allow myself to + +write that. + +I must write it in radians. + +A constant. + +OK, don't forget the great +result from today. + +We filled in the one power that +was missing, and we're + +ready to go. + +Thank you. + +NARRATOR: This has been +a production of MIT + +OpenCourseWare and +Gilbert Strang. + +Funding for this video was +provided by the Lord + +Foundation. + +To help OCW continue to provide +free and open access + +to MIT courses, please +make a donation at + +ocw.mit.edu/donate. \ No newline at end of file diff --git a/caonmXHGB60.txt b/caonmXHGB60.txt new file mode 100644 index 0000000000000000000000000000000000000000..d9c4a2954ec3324f66359b7d0ac6327d3240dca3 --- /dev/null +++ b/caonmXHGB60.txt @@ -0,0 +1,8267 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +to view additional materials from + + align:start position:0% +to view additional materials from + + + align:start position:0% +to view additional materials from +hundreds of MIT courses visit MIT open + + align:start position:0% +hundreds of MIT courses visit MIT open + + + align:start position:0% +hundreds of MIT courses visit MIT open +courseware at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu there were five types of + + align:start position:0% +ocw.mit.edu there were five types of + + + align:start position:0% +ocw.mit.edu there were five types of +problems we just did two + + align:start position:0% +problems we just did two + + + align:start position:0% +problems we just did two +and now I'm going to convince you that + + align:start position:0% +and now I'm going to convince you that + + + align:start position:0% +and now I'm going to convince you that +salt and water problems are in fact the + + align:start position:0% +salt and water problems are in fact the + + + align:start position:0% +salt and water problems are in fact the +same as weak acid weak based + + align:start position:0% +same as weak acid weak based + + + align:start position:0% +same as weak acid weak based +problems so we're going to move now to + + align:start position:0% +problems so we're going to move now to + + + align:start position:0% +problems so we're going to move now to +today's + + align:start position:0% + + + + align:start position:0% + +handout so the pH of a salt + + align:start position:0% + + + + align:start position:0% + +solution is determined by what made that + + align:start position:0% +solution is determined by what made that + + + align:start position:0% +solution is determined by what made that +salt so a salt is formed when you + + align:start position:0% +salt so a salt is formed when you + + + align:start position:0% +salt so a salt is formed when you +neutralize an acid with a base or a base + + align:start position:0% +neutralize an acid with a base or a base + + + align:start position:0% +neutralize an acid with a base or a base +with an + + align:start position:0% +with an + + + align:start position:0% +with an +acid and so depending on what acid and + + align:start position:0% +acid and so depending on what acid and + + + align:start position:0% +acid and so depending on what acid and +which base were used and mixed together + + align:start position:0% +which base were used and mixed together + + + align:start position:0% +which base were used and mixed together +the salt might have different a + + align:start position:0% +the salt might have different a + + + align:start position:0% +the salt might have different a +different pH so an example here if we + + align:start position:0% +different pH so an example here if we + + + align:start position:0% +different pH so an example here if we +had + + align:start position:0% +had + + + align:start position:0% +had +HCL and NaOH that's going to give our + + align:start position:0% +HCL and NaOH that's going to give our + + + align:start position:0% +HCL and NaOH that's going to give our +friend table salt NAC and + + align:start position:0% +friend table salt NAC and + + + align:start position:0% +friend table salt NAC and +water the pH of the salt in water is not + + align:start position:0% +water the pH of the salt in water is not + + + align:start position:0% +water the pH of the salt in water is not +always neutral in this case it would be + + align:start position:0% +always neutral in this case it would be + + + align:start position:0% +always neutral in this case it would be +but it's not always neutral it depends + + align:start position:0% +but it's not always neutral it depends + + + align:start position:0% +but it's not always neutral it depends +on the nature of the acid and the nature + + align:start position:0% +on the nature of the acid and the nature + + + align:start position:0% +on the nature of the acid and the nature +of the base that we're mixed together to + + align:start position:0% +of the base that we're mixed together to + + + align:start position:0% +of the base that we're mixed together to +form that salt so there's some + + align:start position:0% +form that salt so there's some + + + align:start position:0% +form that salt so there's some +rules to help you figure out whether + + align:start position:0% +rules to help you figure out whether + + + align:start position:0% +rules to help you figure out whether +something's going to be acidic or + + align:start position:0% +something's going to be acidic or + + + align:start position:0% +something's going to be acidic or +basic and if you have a salt that + + align:start position:0% +basic and if you have a salt that + + + align:start position:0% +basic and if you have a salt that +contains conjugate acids in ba conjugate + + align:start position:0% +contains conjugate acids in ba conjugate + + + align:start position:0% +contains conjugate acids in ba conjugate +acid of a weak base so it has a + + align:start position:0% +acid of a weak base so it has a + + + align:start position:0% +acid of a weak base so it has a +conjugate acid in it will produce an + + align:start position:0% +conjugate acid in it will produce an + + + align:start position:0% +conjugate acid in it will produce an +acidic + + align:start position:0% +acidic + + + align:start position:0% +acidic +solution and if you have a salt that has + + align:start position:0% +solution and if you have a salt that has + + + align:start position:0% +solution and if you have a salt that has +small highly charged metal cats like + + align:start position:0% +small highly charged metal cats like + + + align:start position:0% +small highly charged metal cats like +iron plus three that will also be + + align:start position:0% +iron plus three that will also be + + + align:start position:0% +iron plus three that will also be +acidic so we saw last time I had the + + align:start position:0% +acidic so we saw last time I had the + + + align:start position:0% +acidic so we saw last time I had the +medicine from prescription medicine for + + align:start position:0% +medicine from prescription medicine for + + + align:start position:0% +medicine from prescription medicine for +my daughter which was iron sulfate was + + align:start position:0% +my daughter which was iron sulfate was + + + align:start position:0% +my daughter which was iron sulfate was +highly + + align:start position:0% +highly + + + align:start position:0% +highly +acidic so note that periodic table group + + align:start position:0% +acidic so note that periodic table group + + + align:start position:0% +acidic so note that periodic table group +one and group two ions lithium plus 1 + + align:start position:0% +one and group two ions lithium plus 1 + + + align:start position:0% +one and group two ions lithium plus 1 +calcium plus two sodium + one um any + + align:start position:0% +calcium plus two sodium + one um any + + + align:start position:0% +calcium plus two sodium + one um any +these are all going to be + + align:start position:0% + + + + align:start position:0% + +neutral and in fact anything plus one + + align:start position:0% +neutral and in fact anything plus one + + + align:start position:0% +neutral and in fact anything plus one +neutral and then salts that can take + + align:start position:0% +neutral and then salts that can take + + + align:start position:0% +neutral and then salts that can take +conjugate bases of weak acids will + + align:start position:0% +conjugate bases of weak acids will + + + align:start position:0% +conjugate bases of weak acids will +produce basic solution so you're going + + align:start position:0% +produce basic solution so you're going + + + align:start position:0% +produce basic solution so you're going +to be asking yourself does this solution + + align:start position:0% +to be asking yourself does this solution + + + align:start position:0% +to be asking yourself does this solution +have a conjugate acid of a weak base + + align:start position:0% +have a conjugate acid of a weak base + + + align:start position:0% +have a conjugate acid of a weak base +does it have a conjugate base of a weak + + align:start position:0% +does it have a conjugate base of a weak + + + align:start position:0% +does it have a conjugate base of a weak +acid does it have have group one group + + align:start position:0% +acid does it have have group one group + + + align:start position:0% +acid does it have have group one group +two what's in there and then you can + + align:start position:0% +two what's in there and then you can + + + align:start position:0% +two what's in there and then you can +think about whether it's going to be + + align:start position:0% +think about whether it's going to be + + + align:start position:0% +think about whether it's going to be +acidic neutral or basic so let's look at + + align:start position:0% +acidic neutral or basic so let's look at + + + align:start position:0% +acidic neutral or basic so let's look at +some + + align:start position:0% +some + + + align:start position:0% +some +examples so we have a salt nh4 CL and we + + align:start position:0% +examples so we have a salt nh4 CL and we + + + align:start position:0% +examples so we have a salt nh4 CL and we +want to figure out is this going to + + align:start position:0% +want to figure out is this going to + + + align:start position:0% +want to figure out is this going to +produce an acidic solution a neutral + + align:start position:0% +produce an acidic solution a neutral + + + align:start position:0% +produce an acidic solution a neutral +solution or a basic solution so we need + + align:start position:0% +solution or a basic solution so we need + + + align:start position:0% +solution or a basic solution so we need +to think about what went into making + + align:start position:0% +to think about what went into making + + + align:start position:0% +to think about what went into making +this salt and we're going to break apart + + align:start position:0% +this salt and we're going to break apart + + + align:start position:0% +this salt and we're going to break apart +the salt and we're going to think about + + align:start position:0% +the salt and we're going to think about + + + align:start position:0% +the salt and we're going to think about +nh4 Plus and we're going to think about + + align:start position:0% +nh4 Plus and we're going to think about + + + align:start position:0% +nh4 Plus and we're going to think about +CL + + align:start position:0% +CL + + + align:start position:0% +CL +minus so let's think about + + align:start position:0% +minus so let's think about + + + align:start position:0% +minus so let's think about +nh4+ first and we're going to ask the + + align:start position:0% +nh4+ first and we're going to ask the + + + align:start position:0% +nh4+ first and we're going to ask the +question is nh4+ a conjugate acid of a + + align:start position:0% +question is nh4+ a conjugate acid of a + + + align:start position:0% +question is nh4+ a conjugate acid of a +weak base and therefore a weak acid + + align:start position:0% +weak base and therefore a weak acid + + + align:start position:0% +weak base and therefore a weak acid +itself one way to answer this question + + align:start position:0% +itself one way to answer this question + + + align:start position:0% +itself one way to answer this question +is to look up the KA for + + align:start position:0% +is to look up the KA for + + + align:start position:0% +is to look up the KA for +nh4+ which happens to be 5.6 * 10us 10 + + align:start position:0% +nh4+ which happens to be 5.6 * 10us 10 + + + align:start position:0% +nh4+ which happens to be 5.6 * 10us 10 +you could also ask about the weak base + + align:start position:0% +you could also ask about the weak base + + + align:start position:0% +you could also ask about the weak base +that it came from the weak base in this + + align:start position:0% +that it came from the weak base in this + + + align:start position:0% +that it came from the weak base in this +case its conjugate base is NH3 and ask + + align:start position:0% +case its conjugate base is NH3 and ask + + + align:start position:0% +case its conjugate base is NH3 and ask +if that's a weak base so if you have + + align:start position:0% +if that's a weak base so if you have + + + align:start position:0% +if that's a weak base so if you have +something that is a con is an acid here + + align:start position:0% +something that is a con is an acid here + + + align:start position:0% +something that is a con is an acid here +you can think about what the base would + + align:start position:0% +you can think about what the base would + + + align:start position:0% +you can think about what the base would +be by removing H+ if you remove H+ from + + align:start position:0% +be by removing H+ if you remove H+ from + + + align:start position:0% +be by removing H+ if you remove H+ from +nh4+ you get NH3 and you can say is NH3 + + align:start position:0% +nh4+ you get NH3 and you can say is NH3 + + + align:start position:0% +nh4+ you get NH3 and you can say is NH3 +a weak base and look up a KB in this + + align:start position:0% +a weak base and look up a KB in this + + + align:start position:0% +a weak base and look up a KB in this +case it's 1.8 * * 10us 5 so what do you + + align:start position:0% +case it's 1.8 * * 10us 5 so what do you + + + align:start position:0% +case it's 1.8 * * 10us 5 so what do you +do you think is this a is this a weak + + align:start position:0% +do you think is this a is this a weak + + + align:start position:0% +do you think is this a is this a weak +base and this a weak acid with those + + align:start position:0% + + + + align:start position:0% + +numbers what do you think is that a weak + + align:start position:0% +numbers what do you think is that a weak + + + align:start position:0% +numbers what do you think is that a weak +weak acid is that a strong acid no so + + align:start position:0% +weak acid is that a strong acid no so + + + align:start position:0% +weak acid is that a strong acid no so +it's a weak acid is this a weak base + + align:start position:0% +it's a weak acid is this a weak base + + + align:start position:0% +it's a weak acid is this a weak base +yeah so we can look also in this uh this + + align:start position:0% +yeah so we can look also in this uh this + + + align:start position:0% +yeah so we can look also in this uh this +chart down here and so NH3 is a + + align:start position:0% +chart down here and so NH3 is a + + + align:start position:0% +chart down here and so NH3 is a +moderately weak base and nh4 plus is a + + align:start position:0% +moderately weak base and nh4 plus is a + + + align:start position:0% +moderately weak base and nh4 plus is a +very weak base but it is I mean weak a + + align:start position:0% +very weak base but it is I mean weak a + + + align:start position:0% +very weak base but it is I mean weak a +very weak acid but it is a weak acid so + + align:start position:0% +very weak acid but it is a weak acid so + + + align:start position:0% +very weak acid but it is a weak acid so +we do have a conjugate acid of a weak + + align:start position:0% +we do have a conjugate acid of a weak + + + align:start position:0% +we do have a conjugate acid of a weak +base so it is acidic not super acidic + + align:start position:0% +base so it is acidic not super acidic + + + align:start position:0% +base so it is acidic not super acidic +but it is acidic and NH3 is a weak base + + align:start position:0% +but it is acidic and NH3 is a weak base + + + align:start position:0% +but it is acidic and NH3 is a weak base +and so we probably had NH3 as our base + + align:start position:0% +and so we probably had NH3 as our base + + + align:start position:0% +and so we probably had NH3 as our base +that was being added and it formed the + + align:start position:0% +that was being added and it formed the + + + align:start position:0% +that was being added and it formed the +conjugate acid in this so then this + + align:start position:0% +conjugate acid in this so then this + + + align:start position:0% +conjugate acid in this so then this +would produce an acidic solution because + + align:start position:0% +would produce an acidic solution because + + + align:start position:0% +would produce an acidic solution because +we have this conjugate acid that's + + align:start position:0% +we have this conjugate acid that's + + + align:start position:0% +we have this conjugate acid that's +formed so from this part just from the + + align:start position:0% +formed so from this part just from the + + + align:start position:0% +formed so from this part just from the +nh4+ it should be + + align:start position:0% +nh4+ it should be + + + align:start position:0% +nh4+ it should be +acidic and now we can consider CL minus + + align:start position:0% +acidic and now we can consider CL minus + + + align:start position:0% +acidic and now we can consider CL minus +so here we're asking the question is CL + + align:start position:0% +so here we're asking the question is CL + + + align:start position:0% +so here we're asking the question is CL +minus a conjugate base of a weak acid + + align:start position:0% +minus a conjugate base of a weak acid + + + align:start position:0% +minus a conjugate base of a weak acid +and therefore itself a weak base and if + + align:start position:0% +and therefore itself a weak base and if + + + align:start position:0% +and therefore itself a weak base and if +you tried to look up the KB of Cl minus + + align:start position:0% +you tried to look up the KB of Cl minus + + + align:start position:0% +you tried to look up the KB of Cl minus +you would not find it in any table but + + align:start position:0% +you would not find it in any table but + + + align:start position:0% +you would not find it in any table but +you could find in a table it's conjugate + + align:start position:0% +you could find in a table it's conjugate + + + align:start position:0% +you could find in a table it's conjugate +acid so if you add H+ to CL minus you + + align:start position:0% +acid so if you add H+ to CL minus you + + + align:start position:0% +acid so if you add H+ to CL minus you +get HCL and so you could look up a KA + + align:start position:0% +get HCL and so you could look up a KA + + + align:start position:0% +get HCL and so you could look up a KA +for that in a table and it's time 10 7 + + align:start position:0% +for that in a table and it's time 10 7 + + + align:start position:0% +for that in a table and it's time 10 7 +so is this a weak acid no it's a strong + + align:start position:0% +so is this a weak acid no it's a strong + + + align:start position:0% +so is this a weak acid no it's a strong +acid so it's not a weak acid it's a + + align:start position:0% +acid so it's not a weak acid it's a + + + align:start position:0% +acid so it's not a weak acid it's a +strong acid so is CL minus going to be + + align:start position:0% + + + + align:start position:0% + +basic no so it is not it is not going to + + align:start position:0% +basic no so it is not it is not going to + + + align:start position:0% +basic no so it is not it is not going to +be a um a basic solution if we look over + + align:start position:0% +be a um a basic solution if we look over + + + align:start position:0% +be a um a basic solution if we look over +here we see HCL is a strong acid and so + + align:start position:0% +here we see HCL is a strong acid and so + + + align:start position:0% +here we see HCL is a strong acid and so +its conjugate base is ineffective at its + + align:start position:0% +its conjugate base is ineffective at its + + + align:start position:0% +its conjugate base is ineffective at its +base it just doesn't work as a base at + + align:start position:0% +base it just doesn't work as a base at + + + align:start position:0% +base it just doesn't work as a base at +all so with a number of 10 to the 7th it + + align:start position:0% +all so with a number of 10 to the 7th it + + + align:start position:0% +all so with a number of 10 to the 7th it +really goes to completion it's a strong + + align:start position:0% +really goes to completion it's a strong + + + align:start position:0% +really goes to completion it's a strong +acid by our definition and so CL minus + + align:start position:0% +acid by our definition and so CL minus + + + align:start position:0% +acid by our definition and so CL minus +is not going to do anything to the + + align:start position:0% +is not going to do anything to the + + + align:start position:0% +is not going to do anything to the +solution it's not going to be useful as + + align:start position:0% +solution it's not going to be useful as + + + align:start position:0% +solution it's not going to be useful as +a weak base so this solution is going to + + align:start position:0% +a weak base so this solution is going to + + + align:start position:0% +a weak base so this solution is going to +be neutral or this the part of the + + align:start position:0% +be neutral or this the part of the + + + align:start position:0% +be neutral or this the part of the +solution due to CL minus will be neutral + + align:start position:0% +solution due to CL minus will be neutral + + + align:start position:0% +solution due to CL minus will be neutral +so here we have something that is acidic + + align:start position:0% +so here we have something that is acidic + + + align:start position:0% +so here we have something that is acidic +and something that's neutral and so + + align:start position:0% +and something that's neutral and so + + + align:start position:0% +and something that's neutral and so +overall the solution is + + align:start position:0% +overall the solution is + + + align:start position:0% +overall the solution is +acidic so you need to break down the two + + align:start position:0% +acidic so you need to break down the two + + + align:start position:0% +acidic so you need to break down the two +parts you had an acid and a base being + + align:start position:0% +parts you had an acid and a base being + + + align:start position:0% +parts you had an acid and a base being +mixed here we had HCL um mixed with um + + align:start position:0% +mixed here we had HCL um mixed with um + + + align:start position:0% +mixed here we had HCL um mixed with um +NH3 and formed this nh4 um CL salt and + + align:start position:0% +NH3 and formed this nh4 um CL salt and + + + align:start position:0% +NH3 and formed this nh4 um CL salt and +that's going to be acidic because HCL + + align:start position:0% +that's going to be acidic because HCL + + + align:start position:0% +that's going to be acidic because HCL +was a weak acid its conjugate is + + align:start position:0% +was a weak acid its conjugate is + + + align:start position:0% +was a weak acid its conjugate is +ineffective whereas NH3 was a weak base + + align:start position:0% +ineffective whereas NH3 was a weak base + + + align:start position:0% +ineffective whereas NH3 was a weak base +so it has a conjugate acid that's a weak + + align:start position:0% +so it has a conjugate acid that's a weak + + + align:start position:0% +so it has a conjugate acid that's a weak +acid a very weak acid but still a weak + + align:start position:0% +acid a very weak acid but still a weak + + + align:start position:0% +acid a very weak acid but still a weak +acid all right so that's how you think + + align:start position:0% +acid all right so that's how you think + + + align:start position:0% +acid all right so that's how you think +about these salt problems so they really + + align:start position:0% +about these salt problems so they really + + + align:start position:0% +about these salt problems so they really +break down to weak acid and weak base + + align:start position:0% +break down to weak acid and weak base + + + align:start position:0% +break down to weak acid and weak base +problems so why don't you give this one + + align:start position:0% +problems so why don't you give this one + + + align:start position:0% +problems so why don't you give this one +a + + align:start position:0% + + + + align:start position:0% + +try all right all right let's just do 10 + + align:start position:0% +try all right all right let's just do 10 + + + align:start position:0% +try all right all right let's just do 10 +more + + align:start position:0% + + + + align:start position:0% + +seconds that is correct all right let's + + align:start position:0% +seconds that is correct all right let's + + + align:start position:0% +seconds that is correct all right let's +look at why that's + + align:start position:0% + + + + align:start position:0% + +correct so it will produce a basic + + align:start position:0% +correct so it will produce a basic + + + align:start position:0% +correct so it will produce a basic +solution so we're going to break it down + + align:start position:0% +solution so we're going to break it down + + + align:start position:0% +solution so we're going to break it down +to to na+ that's one of the things in + + align:start position:0% +to to na+ that's one of the things in + + + align:start position:0% +to to na+ that's one of the things in +there and we ask is na+ a conjugate acid + + align:start position:0% +there and we ask is na+ a conjugate acid + + + align:start position:0% +there and we ask is na+ a conjugate acid +of a weak base is it going to be neutral + + align:start position:0% +of a weak base is it going to be neutral + + + align:start position:0% +of a weak base is it going to be neutral +acidic or basic and what's it going to + + align:start position:0% +acidic or basic and what's it going to + + + align:start position:0% +acidic or basic and what's it going to +be it's going to be neutral it is not a + + align:start position:0% +be it's going to be neutral it is not a + + + align:start position:0% +be it's going to be neutral it is not a +conjugate acid of a weak base it's group + + align:start position:0% +conjugate acid of a weak base it's group + + + align:start position:0% +conjugate acid of a weak base it's group +one it'll be + + align:start position:0% + + + + align:start position:0% + +neutral so this is not contributing to + + align:start position:0% +neutral so this is not contributing to + + + align:start position:0% +neutral so this is not contributing to +the + + align:start position:0% +the + + + align:start position:0% +the +pH so let's look at the second part and + + align:start position:0% +pH so let's look at the second part and + + + align:start position:0% +pH so let's look at the second part and +look at ch3 Co minus so we have this can + + align:start position:0% +look at ch3 Co minus so we have this can + + + align:start position:0% +look at ch3 Co minus so we have this can +be divided into na+ and + + align:start position:0% +be divided into na+ and + + + align:start position:0% +be divided into na+ and +h3c minus and then we ask is this a + + align:start position:0% +h3c minus and then we ask is this a + + + align:start position:0% +h3c minus and then we ask is this a +conjugate base of a weak acid or we + + align:start position:0% +conjugate base of a weak acid or we + + + align:start position:0% +conjugate base of a weak acid or we +could ask the other question is this + + align:start position:0% +could ask the other question is this + + + align:start position:0% +could ask the other question is this +over here a weak acid and the KA for + + align:start position:0% +over here a weak acid and the KA for + + + align:start position:0% +over here a weak acid and the KA for +that was given so is that a weak acid or + + align:start position:0% +that was given so is that a weak acid or + + + align:start position:0% +that was given so is that a weak acid or +a strong acid is it + + align:start position:0% +a strong acid is it + + + align:start position:0% +a strong acid is it +weak or strong weak yes so the answer is + + align:start position:0% +weak or strong weak yes so the answer is + + + align:start position:0% +weak or strong weak yes so the answer is +yes it's weak and so its conjugate base + + align:start position:0% +yes it's weak and so its conjugate base + + + align:start position:0% +yes it's weak and so its conjugate base +would also be a weak + + align:start position:0% +would also be a weak + + + align:start position:0% +would also be a weak +base and so therefore this will be + + align:start position:0% +base and so therefore this will be + + + align:start position:0% +base and so therefore this will be +acidic so sometimes you'll be given Ka + + align:start position:0% +acidic so sometimes you'll be given Ka + + + align:start position:0% +acidic so sometimes you'll be given Ka +sometimes you'll be given KBS if you're + + align:start position:0% +sometimes you'll be given KBS if you're + + + align:start position:0% +sometimes you'll be given KBS if you're +given either one of them you can answer + + align:start position:0% +given either one of them you can answer + + + align:start position:0% +given either one of them you can answer +the question if you want you can convert + + align:start position:0% +the question if you want you can convert + + + align:start position:0% +the question if you want you can convert +your Ka to your KB what would you use to + + align:start position:0% +your Ka to your KB what would you use to + + + align:start position:0% +your Ka to your KB what would you use to +convert Ka to + + align:start position:0% +convert Ka to + + + align:start position:0% +convert Ka to +KB KW right but just with one of these + + align:start position:0% +KB KW right but just with one of these + + + align:start position:0% +KB KW right but just with one of these +pieces of information you should be able + + align:start position:0% +pieces of information you should be able + + + align:start position:0% +pieces of information you should be able +to answer this + + align:start position:0% +to answer this + + + align:start position:0% +to answer this +question so let's just look at the + + align:start position:0% +question so let's just look at the + + + align:start position:0% +question so let's just look at the +general rule now you have a compound + + align:start position:0% +general rule now you have a compound + + + align:start position:0% +general rule now you have a compound +XY that can be broken up into + + align:start position:0% +XY that can be broken up into + + + align:start position:0% +XY that can be broken up into +X+ and you'll ask yourself is X+ a + + align:start position:0% +X+ and you'll ask yourself is X+ a + + + align:start position:0% +X+ and you'll ask yourself is X+ a +conjugate acid of a weak base if yes + + align:start position:0% +conjugate acid of a weak base if yes + + + align:start position:0% +conjugate acid of a weak base if yes +then the solution will be acidic if no + + align:start position:0% +then the solution will be acidic if no + + + align:start position:0% +then the solution will be acidic if no +it'll be + + align:start position:0% +it'll be + + + align:start position:0% +it'll be +neutral for y you have y minus is y + + align:start position:0% +neutral for y you have y minus is y + + + align:start position:0% +neutral for y you have y minus is y +minus a conjugate base of a weak acid if + + align:start position:0% +minus a conjugate base of a weak acid if + + + align:start position:0% +minus a conjugate base of a weak acid if +yes then it's going to be add some basic + + align:start position:0% +yes then it's going to be add some basic + + + align:start position:0% +yes then it's going to be add some basic +uh nature to this if no neutral and then + + align:start position:0% +uh nature to this if no neutral and then + + + align:start position:0% +uh nature to this if no neutral and then +overall you say if it's acidic plus + + align:start position:0% +overall you say if it's acidic plus + + + align:start position:0% +overall you say if it's acidic plus +neutral that's acidic basic plus neutral + + align:start position:0% +neutral that's acidic basic plus neutral + + + align:start position:0% +neutral that's acidic basic plus neutral +basic neutral plus neutral neutral and + + align:start position:0% +basic neutral plus neutral neutral and + + + align:start position:0% +basic neutral plus neutral neutral and +if I give you a question of something + + align:start position:0% +if I give you a question of something + + + align:start position:0% +if I give you a question of something +that is acidic and basic you can answer + + align:start position:0% +that is acidic and basic you can answer + + + align:start position:0% +that is acidic and basic you can answer +the question without doing math because + + align:start position:0% +the question without doing math because + + + align:start position:0% +the question without doing math because +it'll depend on the KA of one thing and + + align:start position:0% +it'll depend on the KA of one thing and + + + align:start position:0% +it'll depend on the KA of one thing and +the KB of the other thing and you'll + + align:start position:0% +the KB of the other thing and you'll + + + align:start position:0% +the KB of the other thing and you'll +have to see which ones a stronger acid + + align:start position:0% +have to see which ones a stronger acid + + + align:start position:0% +have to see which ones a stronger acid +and which one + + align:start position:0% +and which one + + + align:start position:0% +and which one +or a stronger base and so you can't just + + align:start position:0% +or a stronger base and so you can't just + + + align:start position:0% +or a stronger base and so you can't just +simply answer the question now you may + + align:start position:0% +simply answer the question now you may + + + align:start position:0% +simply answer the question now you may +note that I did mention that problem set + + align:start position:0% +note that I did mention that problem set + + + align:start position:0% +note that I did mention that problem set +7even is long it takes a long time to do + + align:start position:0% +7even is long it takes a long time to do + + + align:start position:0% +7even is long it takes a long time to do +these problems and so an exam writing a + + align:start position:0% +these problems and so an exam writing a + + + align:start position:0% +these problems and so an exam writing a +fair exam when the problems take a long + + align:start position:0% +fair exam when the problems take a long + + + align:start position:0% +fair exam when the problems take a long +time to do is hard but these are short + + align:start position:0% +time to do is hard but these are short + + + align:start position:0% +time to do is hard but these are short +little things I could ask you to predict + + align:start position:0% +little things I could ask you to predict + + + align:start position:0% +little things I could ask you to predict +the pH of salt by just thinking about + + align:start position:0% +the pH of salt by just thinking about + + + align:start position:0% +the pH of salt by just thinking about +things and looking up some KBS and some + + align:start position:0% +things and looking up some KBS and some + + + align:start position:0% +things and looking up some KBS and some +Ka so these are good short questions on + + align:start position:0% +Ka so these are good short questions on + + + align:start position:0% +Ka so these are good short questions on +the exam so I'm probably not going to + + align:start position:0% +the exam so I'm probably not going to + + + align:start position:0% +the exam so I'm probably not going to +give you one if it's supposed to be a + + align:start position:0% +give you one if it's supposed to be a + + + align:start position:0% +give you one if it's supposed to be a +short question that is an acid and a + + align:start position:0% +short question that is an acid and a + + + align:start position:0% +short question that is an acid and a +base mixed uh mixed together because + + align:start position:0% +base mixed uh mixed together because + + + align:start position:0% +base mixed uh mixed together because +then you'd have to do some math so uh + + align:start position:0% +then you'd have to do some math so uh + + + align:start position:0% +then you'd have to do some math so uh +keep that keep that in mind all right so + + align:start position:0% +keep that keep that in mind all right so + + + align:start position:0% +keep that keep that in mind all right so +salts salt and water problems are really + + align:start position:0% +salts salt and water problems are really + + + align:start position:0% +salts salt and water problems are really +just weak acid in water or weak base in + + align:start position:0% +just weak acid in water or weak base in + + + align:start position:0% +just weak acid in water or weak base in +water problems which you already know + + align:start position:0% +water problems which you already know + + + align:start position:0% +water problems which you already know +how to do so we're going to move on now + + align:start position:0% +how to do so we're going to move on now + + + align:start position:0% +how to do so we're going to move on now +to + + align:start position:0% + + + + align:start position:0% + +buffers + + align:start position:0% +buffers + + + align:start position:0% +buffers +buffers so a buffer is a solution that + + align:start position:0% +buffers so a buffer is a solution that + + + align:start position:0% +buffers so a buffer is a solution that +maintains + + align:start position:0% +maintains + + + align:start position:0% +maintains +approximately a constant pH there'll be + + align:start position:0% +approximately a constant pH there'll be + + + align:start position:0% +approximately a constant pH there'll be +a little range of pH that can change but + + align:start position:0% +a little range of pH that can change but + + + align:start position:0% +a little range of pH that can change but +the buffer tries to keep the pH constant + + align:start position:0% +the buffer tries to keep the pH constant + + + align:start position:0% +the buffer tries to keep the pH constant +you use a buffer to keep pH constant why + + align:start position:0% +you use a buffer to keep pH constant why + + + align:start position:0% +you use a buffer to keep pH constant why +is this important well buffers are are + + align:start position:0% +is this important well buffers are are + + + align:start position:0% +is this important well buffers are are +very important in biology we all work at + + align:start position:0% +very important in biology we all work at + + + align:start position:0% +very important in biology we all work at +a constant pH living things need to be + + align:start position:0% +a constant pH living things need to be + + + align:start position:0% +a constant pH living things need to be +at a constant pH but a lot of times + + align:start position:0% +at a constant pH but a lot of times + + + align:start position:0% +at a constant pH but a lot of times +chemical processes also need to be at a + + align:start position:0% +chemical processes also need to be at a + + + align:start position:0% +chemical processes also need to be at a +constant pH and here's just uh one + + align:start position:0% +constant pH and here's just uh one + + + align:start position:0% +constant pH and here's just uh one +example of why buffers are important um + + align:start position:0% +example of why buffers are important um + + + align:start position:0% +example of why buffers are important um +we're looking for alternative energy + + align:start position:0% +we're looking for alternative energy + + + align:start position:0% +we're looking for alternative energy +we're trying to develop Alternative + + align:start position:0% +we're trying to develop Alternative + + + align:start position:0% +we're trying to develop Alternative +Energy there's this idea of creating + + align:start position:0% +Energy there's this idea of creating + + + align:start position:0% +Energy there's this idea of creating +fuel cells that employ microbes these + + align:start position:0% +fuel cells that employ microbes these + + + align:start position:0% +fuel cells that employ microbes these +little uh red circles or microbes here + + align:start position:0% +little uh red circles or microbes here + + + align:start position:0% +little uh red circles or microbes here +there are microbes like um + + align:start position:0% +there are microbes like um + + + align:start position:0% +there are microbes like um +shanella that will live adhere to + + align:start position:0% +shanella that will live adhere to + + + align:start position:0% +shanella that will live adhere to +electrodes will live on a surfaces of + + align:start position:0% +electrodes will live on a surfaces of + + + align:start position:0% +electrodes will live on a surfaces of +electrodes metal electrodes and they + + align:start position:0% +electrodes metal electrodes and they + + + align:start position:0% +electrodes metal electrodes and they +will eat things like sugar and Organics + + align:start position:0% +will eat things like sugar and Organics + + + align:start position:0% +will eat things like sugar and Organics +and they will U respirate electrons into + + align:start position:0% +and they will U respirate electrons into + + + align:start position:0% +and they will U respirate electrons into +the metal electrodes so the electrons go + + align:start position:0% +the metal electrodes so the electrons go + + + align:start position:0% +the metal electrodes so the electrons go +in and you create an electric current + + align:start position:0% +in and you create an electric current + + + align:start position:0% +in and you create an electric current +and you can do uh have a fuel cell so + + align:start position:0% +and you can do uh have a fuel cell so + + + align:start position:0% +and you can do uh have a fuel cell so +it's a way of generating an electric + + align:start position:0% +it's a way of generating an electric + + + align:start position:0% +it's a way of generating an electric +current and then people have other ideas + + align:start position:0% +current and then people have other ideas + + + align:start position:0% +current and then people have other ideas +that some some microbes live in + + align:start position:0% +that some some microbes live in + + + align:start position:0% +that some some microbes live in +electrodes other microbes like moral + + align:start position:0% +electrodes other microbes like moral + + + align:start position:0% +electrodes other microbes like moral +thos um they live on carbon dioxide + + align:start position:0% +thos um they live on carbon dioxide + + + align:start position:0% +thos um they live on carbon dioxide +they convert carbon dioxide to things + + align:start position:0% +they convert carbon dioxide to things + + + align:start position:0% +they convert carbon dioxide to things +like acetyl COA which is a fuel so you + + align:start position:0% +like acetyl COA which is a fuel so you + + + align:start position:0% +like acetyl COA which is a fuel so you +throw those in there and then you like + + align:start position:0% +throw those in there and then you like + + + align:start position:0% +throw those in there and then you like +pump in CO2 and you make uh electric + + align:start position:0% +pump in CO2 and you make uh electric + + + align:start position:0% +pump in CO2 and you make uh electric +currents so there's a lot of great ideas + + align:start position:0% +currents so there's a lot of great ideas + + + align:start position:0% +currents so there's a lot of great ideas +of using microbes so some of my research + + align:start position:0% +of using microbes so some of my research + + + align:start position:0% +of using microbes so some of my research +relates to understanding the + + align:start position:0% +relates to understanding the + + + align:start position:0% +relates to understanding the +fundamentals of these Pathways and every + + align:start position:0% +fundamentals of these Pathways and every + + + align:start position:0% +fundamentals of these Pathways and every +once in a while I venture to hear one of + + align:start position:0% +once in a while I venture to hear one of + + + align:start position:0% +once in a while I venture to hear one of +these kind of um big energy talks about + + align:start position:0% +these kind of um big energy talks about + + + align:start position:0% +these kind of um big energy talks about +you know how is the development coming + + align:start position:0% +you know how is the development coming + + + align:start position:0% +you know how is the development coming +of these ideas and so I heard one talk + + align:start position:0% +of these ideas and so I heard one talk + + + align:start position:0% +of these ideas and so I heard one talk +and I I um was listening you I was I + + align:start position:0% +and I I um was listening you I was I + + + align:start position:0% +and I I um was listening you I was I +want you know you know is this really + + align:start position:0% +want you know you know is this really + + + align:start position:0% +want you know you know is this really +working are people getting this to work + + align:start position:0% +working are people getting this to work + + + align:start position:0% +working are people getting this to work +what's sort of the status and they + + align:start position:0% +what's sort of the status and they + + + align:start position:0% +what's sort of the status and they +talked about a lot of technical + + align:start position:0% +talked about a lot of technical + + + align:start position:0% +talked about a lot of technical +difficulties of getting it to work but + + align:start position:0% +difficulties of getting it to work but + + + align:start position:0% +difficulties of getting it to work but +they had discovered something amazing + + align:start position:0% +they had discovered something amazing + + + align:start position:0% +they had discovered something amazing +something that might really change the + + align:start position:0% +something that might really change the + + + align:start position:0% +something that might really change the +ability to do this and it turned out + + align:start position:0% +ability to do this and it turned out + + + align:start position:0% +ability to do this and it turned out +that when you're generating all this + + align:start position:0% +that when you're generating all this + + + align:start position:0% +that when you're generating all this +negative charge you need to have + + align:start position:0% +negative charge you need to have + + + align:start position:0% +negative charge you need to have +positive charge around like H+ for + + align:start position:0% +positive charge around like H+ for + + + align:start position:0% +positive charge around like H+ for +example and so you need to have protons + + align:start position:0% +example and so you need to have protons + + + align:start position:0% +example and so you need to have protons +but it mattered the concentration of + + align:start position:0% +but it mattered the concentration of + + + align:start position:0% +but it mattered the concentration of +those protons and they kind of had to be + + align:start position:0% +those protons and they kind of had to be + + + align:start position:0% +those protons and they kind of had to be +kept + + align:start position:0% +kept + + + align:start position:0% +kept +constant and they + + align:start position:0% +constant and they + + + align:start position:0% +constant and they +discovered buff + + align:start position:0% + + + + align:start position:0% + +ERS 50 minutes of my life this was a + + align:start position:0% +ERS 50 minutes of my life this was a + + + align:start position:0% +ERS 50 minutes of my life this was a +talk at MIT the person discovered + + align:start position:0% +talk at MIT the person discovered + + + align:start position:0% +talk at MIT the person discovered +buffers I just felt like writing a + + align:start position:0% +buffers I just felt like writing a + + + align:start position:0% +buffers I just felt like writing a +letter to Washington saying can I have + + align:start position:0% +letter to Washington saying can I have + + + align:start position:0% +letter to Washington saying can I have +their research dollars because I already + + align:start position:0% +their research dollars because I already + + + align:start position:0% +their research dollars because I already +know about buffers I don't need to do a + + align:start position:0% +know about buffers I don't need to do a + + + align:start position:0% +know about buffers I don't need to do a +big research project to discover that + + align:start position:0% +big research project to discover that + + + align:start position:0% +big research project to discover that +buffers keep things a constant pH and + + align:start position:0% +buffers keep things a constant pH and + + + align:start position:0% +buffers keep things a constant pH and +that when you're using living organisms + + align:start position:0% +that when you're using living organisms + + + align:start position:0% +that when you're using living organisms +and doing experiments and doing + + align:start position:0% +and doing experiments and doing + + + align:start position:0% +and doing experiments and doing +reactions pH matters I already knew that + + align:start position:0% +reactions pH matters I already knew that + + + align:start position:0% +reactions pH matters I already knew that +everyone who takes 5111 already knows + + align:start position:0% +everyone who takes 5111 already knows + + + align:start position:0% +everyone who takes 5111 already knows +that and so this is part of the reason + + align:start position:0% +that and so this is part of the reason + + + align:start position:0% +that and so this is part of the reason +I'm teaching you this because you're + + align:start position:0% +I'm teaching you this because you're + + + align:start position:0% +I'm teaching you this because you're +some of you will not go on and study + + align:start position:0% +some of you will not go on and study + + + align:start position:0% +some of you will not go on and study +chemistry you'll be doing engineering + + align:start position:0% +chemistry you'll be doing engineering + + + align:start position:0% +chemistry you'll be doing engineering +you'll be doing Alternative Energy + + align:start position:0% +you'll be doing Alternative Energy + + + align:start position:0% +you'll be doing Alternative Energy +you'll doing all sorts of things and you + + align:start position:0% +you'll doing all sorts of things and you + + + align:start position:0% +you'll doing all sorts of things and you +can be the person in the room that + + align:start position:0% +can be the person in the room that + + + align:start position:0% +can be the person in the room that +raises your hand and go it's called a + + align:start position:0% +raises your hand and go it's called a + + + align:start position:0% +raises your hand and go it's called a +buffer and that is going to change the + + align:start position:0% +buffer and that is going to change the + + + align:start position:0% +buffer and that is going to change the +speed of that research they're just like + + align:start position:0% +speed of that research they're just like + + + align:start position:0% +speed of that research they're just like +right away they're going to be using + + align:start position:0% +right away they're going to be using + + + align:start position:0% +right away they're going to be using +buffers and when you do problem set + + align:start position:0% +buffers and when you do problem set + + + align:start position:0% +buffers and when you do problem set +7even you're going to know how to make a + + align:start position:0% +7even you're going to know how to make a + + + align:start position:0% +7even you're going to know how to make a +buffer so you can not only raise your + + align:start position:0% +buffer so you can not only raise your + + + align:start position:0% +buffer so you can not only raise your +hand and say it's called a buffer you + + align:start position:0% +hand and say it's called a buffer you + + + align:start position:0% +hand and say it's called a buffer you +could tell people how to make a buffer + + align:start position:0% +could tell people how to make a buffer + + + align:start position:0% +could tell people how to make a buffer +to use in their experiments so this is + + align:start position:0% +to use in their experiments so this is + + + align:start position:0% +to use in their experiments so this is +why the material I'm teaching you is + + align:start position:0% +why the material I'm teaching you is + + + align:start position:0% +why the material I'm teaching you is +really important I go out there and I + + align:start position:0% +really important I go out there and I + + + align:start position:0% +really important I go out there and I +hear these talks of people who are + + align:start position:0% +hear these talks of people who are + + + align:start position:0% +hear these talks of people who are +trying to do these Innovative things but + + align:start position:0% +trying to do these Innovative things but + + + align:start position:0% +trying to do these Innovative things but +they're lacking fundamental chemistry + + align:start position:0% +they're lacking fundamental chemistry + + + align:start position:0% +they're lacking fundamental chemistry +knowledge that's hindering their ability + + align:start position:0% +knowledge that's hindering their ability + + + align:start position:0% +knowledge that's hindering their ability +to do it so I want all of you to have + + align:start position:0% +to do it so I want all of you to have + + + align:start position:0% +to do it so I want all of you to have +this knowledge whether you study + + align:start position:0% +this knowledge whether you study + + + align:start position:0% +this knowledge whether you study +chemistry anymore or not so that you can + + align:start position:0% +chemistry anymore or not so that you can + + + align:start position:0% +chemistry anymore or not so that you can +be the person who brings the basic + + align:start position:0% +be the person who brings the basic + + + align:start position:0% +be the person who brings the basic +chemical principles into the design + + align:start position:0% +chemical principles into the design + + + align:start position:0% +chemical principles into the design +process and I care a lot about + + align:start position:0% +process and I care a lot about + + + align:start position:0% +process and I care a lot about +Alternative Energy it's going to be + + align:start position:0% +Alternative Energy it's going to be + + + align:start position:0% +Alternative Energy it's going to be +super important in the future I care + + align:start position:0% +super important in the future I care + + + align:start position:0% +super important in the future I care +that we don't destroy our planet going + + align:start position:0% +that we don't destroy our planet going + + + align:start position:0% +that we don't destroy our planet going +after some forms of energy and these + + align:start position:0% +after some forms of energy and these + + + align:start position:0% +after some forms of energy and these +idea of using microbes is a great one + + align:start position:0% +idea of using microbes is a great one + + + align:start position:0% +idea of using microbes is a great one +but we just need people who know how to + + align:start position:0% +but we just need people who know how to + + + align:start position:0% +but we just need people who know how to +work with them to get it to to to go + + align:start position:0% +work with them to get it to to to go + + + align:start position:0% +work with them to get it to to to go +right all right so + + align:start position:0% +right all right so + + + align:start position:0% +right all right so +buffers what are buffers you got to know + + align:start position:0% +buffers what are buffers you got to know + + + align:start position:0% +buffers what are buffers you got to know +about + + align:start position:0% +about + + + align:start position:0% +about +buffers a buffer consists an acid buffer + + align:start position:0% +buffers a buffer consists an acid buffer + + + align:start position:0% +buffers a buffer consists an acid buffer +consists of a weak acid and its + + align:start position:0% +consists of a weak acid and its + + + align:start position:0% +consists of a weak acid and its +conjugate base they're often supplied as + + align:start position:0% +conjugate base they're often supplied as + + + align:start position:0% +conjugate base they're often supplied as +a salt which means you have a counter + + align:start position:0% +a salt which means you have a counter + + + align:start position:0% +a salt which means you have a counter +ion that comes with it like sodium Plus + + align:start position:0% +ion that comes with it like sodium Plus + + + align:start position:0% +ion that comes with it like sodium Plus +or CL minus and it buffers on the acidic + + align:start position:0% +or CL minus and it buffers on the acidic + + + align:start position:0% +or CL minus and it buffers on the acidic +side of + + align:start position:0% +side of + + + align:start position:0% +side of +neutral a base buffer or a basic buffer + + align:start position:0% +neutral a base buffer or a basic buffer + + + align:start position:0% +neutral a base buffer or a basic buffer +has a weak base and it's conjugate acid + + align:start position:0% +has a weak base and it's conjugate acid + + + align:start position:0% +has a weak base and it's conjugate acid +often supplied as a salt and it buffers + + align:start position:0% +often supplied as a salt and it buffers + + + align:start position:0% +often supplied as a salt and it buffers +on the basic side of neutral so the key + + align:start position:0% +on the basic side of neutral so the key + + + align:start position:0% +on the basic side of neutral so the key +to a buffer is that that it has a + + align:start position:0% +to a buffer is that that it has a + + + align:start position:0% +to a buffer is that that it has a +conjugate acid it has an ha but it also + + align:start position:0% +conjugate acid it has an ha but it also + + + align:start position:0% +conjugate acid it has an ha but it also +has the conjugate base it has a minus if + + align:start position:0% +has the conjugate base it has a minus if + + + align:start position:0% +has the conjugate base it has a minus if +it just has a ha it's a weak acid that's + + align:start position:0% +it just has a ha it's a weak acid that's + + + align:start position:0% +it just has a ha it's a weak acid that's +not a buffer that's a weak acid if you + + align:start position:0% +not a buffer that's a weak acid if you + + + align:start position:0% +not a buffer that's a weak acid if you +just have a + + align:start position:0% +just have a + + + align:start position:0% +just have a +minus you just have your base that's not + + align:start position:0% +minus you just have your base that's not + + + align:start position:0% +minus you just have your base that's not +a buffer you need to be both an acid and + + align:start position:0% +a buffer you need to be both an acid and + + + align:start position:0% +a buffer you need to be both an acid and +a base a base and an acid an acid and a + + align:start position:0% +a base a base and an acid an acid and a + + + align:start position:0% +a base a base and an acid an acid and a +base on exam people do buffer problems + + align:start position:0% +base on exam people do buffer problems + + + align:start position:0% +base on exam people do buffer problems +and they just have one they don't have + + align:start position:0% +and they just have one they don't have + + + align:start position:0% +and they just have one they don't have +the other that's not a buffer and I'm + + align:start position:0% +the other that's not a buffer and I'm + + + align:start position:0% +the other that's not a buffer and I'm +going to write on your little exam + + align:start position:0% +going to write on your little exam + + + align:start position:0% +going to write on your little exam +remember me twirling around the room it + + align:start position:0% +remember me twirling around the room it + + + align:start position:0% +remember me twirling around the room it +was an acid and a base I don't think you + + align:start position:0% +was an acid and a base I don't think you + + + align:start position:0% +was an acid and a base I don't think you +can never forget this this will be in + + align:start position:0% +can never forget this this will be in + + + align:start position:0% +can never forget this this will be in +your brain + + align:start position:0% +your brain + + + align:start position:0% +your brain +forever buffer has an acid and a + + align:start position:0% +forever buffer has an acid and a + + + align:start position:0% +forever buffer has an acid and a +conjugate base a conjugate base and a + + align:start position:0% +conjugate base a conjugate base and a + + + align:start position:0% +conjugate base a conjugate base and a +conjugate acid okay let's look at some + + align:start position:0% + + + + align:start position:0% + +examples so if you mix acetic + + align:start position:0% +examples so if you mix acetic + + + align:start position:0% +examples so if you mix acetic +acid and acetate salt it's conjugate + + align:start position:0% +acid and acetate salt it's conjugate + + + align:start position:0% +acid and acetate salt it's conjugate +buff conjugate base supplied in the form + + align:start position:0% +buff conjugate base supplied in the form + + + align:start position:0% +buff conjugate base supplied in the form +of a salt so here we have the acetic + + align:start position:0% +of a salt so here we have the acetic + + + align:start position:0% +of a salt so here we have the acetic +acid here we have the acetate the + + align:start position:0% +acid here we have the acetate the + + + align:start position:0% +acid here we have the acetate the +conjugate base often will be supplied + + align:start position:0% +conjugate base often will be supplied + + + align:start position:0% +conjugate base often will be supplied +there's probably going to be some na+ + + align:start position:0% +there's probably going to be some na+ + + + align:start position:0% +there's probably going to be some na+ +around and you get this dynamic + + align:start position:0% +around and you get this dynamic + + + align:start position:0% +around and you get this dynamic +equilibrium it goes forward it goes back + + align:start position:0% +equilibrium it goes forward it goes back + + + align:start position:0% +equilibrium it goes forward it goes back +it goes forward it goes + + align:start position:0% +it goes forward it goes + + + align:start position:0% +it goes forward it goes +back so when you have this if you added + + align:start position:0% +back so when you have this if you added + + + align:start position:0% +back so when you have this if you added +a strong acid to this solution you put + + align:start position:0% +a strong acid to this solution you put + + + align:start position:0% +a strong acid to this solution you put +in more acid into + + align:start position:0% +in more acid into + + + align:start position:0% +in more acid into +this and you had equal amounts of this + + align:start position:0% +this and you had equal amounts of this + + + align:start position:0% +this and you had equal amounts of this +and + + align:start position:0% +and + + + align:start position:0% +and +this then your conjugate base is going + + align:start position:0% +this then your conjugate base is going + + + align:start position:0% +this then your conjugate base is going +to react with the strong + + align:start position:0% +to react with the strong + + + align:start position:0% +to react with the strong +acid and you're going to go in the back + + align:start position:0% +acid and you're going to go in the back + + + align:start position:0% +acid and you're going to go in the back +Direction and you're going to neutralize + + align:start position:0% +Direction and you're going to neutralize + + + align:start position:0% +Direction and you're going to neutralize +that acid that was added and the pH + + align:start position:0% +that acid that was added and the pH + + + align:start position:0% +that acid that was added and the pH +should stay more or less the same if you + + align:start position:0% +should stay more or less the same if you + + + align:start position:0% +should stay more or less the same if you +did a good job making your buffer + + align:start position:0% +did a good job making your buffer + + + align:start position:0% +did a good job making your buffer +so the buffer can respond to the changes + + align:start position:0% +so the buffer can respond to the changes + + + align:start position:0% +so the buffer can respond to the changes +in PH by shifts in different directions + + align:start position:0% +in PH by shifts in different directions + + + align:start position:0% +in PH by shifts in different directions +to use up the extra added acid or the + + align:start position:0% +to use up the extra added acid or the + + + align:start position:0% +to use up the extra added acid or the +other way the extra added base so in + + align:start position:0% +other way the extra added base so in + + + align:start position:0% +other way the extra added base so in +this case the acid that's added is + + align:start position:0% +this case the acid that's added is + + + align:start position:0% +this case the acid that's added is +effectively removed and the pH stays the + + align:start position:0% +effectively removed and the pH stays the + + + align:start position:0% +effectively removed and the pH stays the +same so a buffer can respond to added + + align:start position:0% +same so a buffer can respond to added + + + align:start position:0% +same so a buffer can respond to added +acid a buffer can also respond to added + + align:start position:0% +acid a buffer can also respond to added + + + align:start position:0% +acid a buffer can also respond to added +base if you add a base a strong base or + + align:start position:0% +base if you add a base a strong base or + + + align:start position:0% +base if you add a base a strong base or +any kind of + + align:start position:0% +any kind of + + + align:start position:0% +any kind of +base and in this case hydroxide ion + + align:start position:0% +base and in this case hydroxide ion + + + align:start position:0% +base and in this case hydroxide ion +would then remove a proton from the weak + + align:start position:0% +would then remove a proton from the weak + + + align:start position:0% +would then remove a proton from the weak +acid from the acetic acid forming water + + align:start position:0% +acid from the acetic acid forming water + + + align:start position:0% +acid from the acetic acid forming water +and some more of the conjugate + + align:start position:0% +and some more of the conjugate + + + align:start position:0% +and some more of the conjugate +base and it's effectively removed as + + align:start position:0% +base and it's effectively removed as + + + align:start position:0% +base and it's effectively removed as +well and those o ions are effectively + + align:start position:0% +well and those o ions are effectively + + + align:start position:0% +well and those o ions are effectively +removed and again if you did a good job + + align:start position:0% +removed and again if you did a good job + + + align:start position:0% +removed and again if you did a good job +designing this buffer the pH should stay + + align:start position:0% +designing this buffer the pH should stay + + + align:start position:0% +designing this buffer the pH should stay +constant + + align:start position:0% +constant + + + align:start position:0% +constant +so that's why you need the conjugate + + align:start position:0% +so that's why you need the conjugate + + + align:start position:0% +so that's why you need the conjugate +acid and the conjugate base you need the + + align:start position:0% +acid and the conjugate base you need the + + + align:start position:0% +acid and the conjugate base you need the +acid to react with the base that's added + + align:start position:0% +acid to react with the base that's added + + + align:start position:0% +acid to react with the base that's added +and keep the pH constant you need the + + align:start position:0% +and keep the pH constant you need the + + + align:start position:0% +and keep the pH constant you need the +base to react with the acid that's added + + align:start position:0% +base to react with the acid that's added + + + align:start position:0% +base to react with the acid that's added +and keep the pH constant if you just + + align:start position:0% +and keep the pH constant if you just + + + align:start position:0% +and keep the pH constant if you just +have one it's not going to be a + + align:start position:0% +have one it's not going to be a + + + align:start position:0% +have one it's not going to be a +buffer all right so buffer action again + + align:start position:0% +buffer all right so buffer action again + + + align:start position:0% +buffer all right so buffer action again +weak acid transfers its protons it's H+ + + align:start position:0% +weak acid transfers its protons it's H+ + + + align:start position:0% +weak acid transfers its protons it's H+ +to O supplied by the base so here we + + align:start position:0% +to O supplied by the base so here we + + + align:start position:0% +to O supplied by the base so here we +have added we have added base and it's + + align:start position:0% +have added we have added base and it's + + + align:start position:0% +have added we have added base and it's +going to be reacted with the acid to be + + align:start position:0% +going to be reacted with the acid to be + + + align:start position:0% +going to be reacted with the acid to be +neutralized a conjugate um the conjugate + + align:start position:0% +neutralized a conjugate um the conjugate + + + align:start position:0% +neutralized a conjugate um the conjugate +base a minus can accept protons from an + + align:start position:0% +base a minus can accept protons from an + + + align:start position:0% +base a minus can accept protons from an +supplied acid if you add an acid it will + + align:start position:0% +supplied acid if you add an acid it will + + + align:start position:0% +supplied acid if you add an acid it will +take those and will neutralize the acid + + align:start position:0% +take those and will neutralize the acid + + + align:start position:0% +take those and will neutralize the acid +that's + + align:start position:0% + + + + align:start position:0% + +added so let's think about what type of + + align:start position:0% +added so let's think about what type of + + + align:start position:0% +added so let's think about what type of +acids and conjugate bases are going to + + align:start position:0% +acids and conjugate bases are going to + + + align:start position:0% +acids and conjugate bases are going to +work to make a good buffer a strong acid + + align:start position:0% +work to make a good buffer a strong acid + + + align:start position:0% +work to make a good buffer a strong acid +in its conjugate base Cas does not make + + align:start position:0% +in its conjugate base Cas does not make + + + align:start position:0% +in its conjugate base Cas does not make +a good buffer why don't you tell me why + + align:start position:0% + + + + align:start position:0% + +yep so + + align:start position:0% +yep so + + + align:start position:0% +yep so +67% so it's really about the fact that + + align:start position:0% +67% so it's really about the fact that + + + align:start position:0% +67% so it's really about the fact that +the conjugate base of a strong acid is + + align:start position:0% +the conjugate base of a strong acid is + + + align:start position:0% +the conjugate base of a strong acid is +really not a base at all it's + + align:start position:0% +really not a base at all it's + + + align:start position:0% +really not a base at all it's +ineffective as a base and that's why + + align:start position:0% +ineffective as a base and that's why + + + align:start position:0% +ineffective as a base and that's why +it's not going to work buffer solution + + align:start position:0% +it's not going to work buffer solution + + + align:start position:0% +it's not going to work buffer solution +has to be in a dynamic equilibrium you + + align:start position:0% +has to be in a dynamic equilibrium you + + + align:start position:0% +has to be in a dynamic equilibrium you +have to be able to push it both ways + + align:start position:0% +have to be able to push it both ways + + + align:start position:0% +have to be able to push it both ways +otherwise it's not going to work so a + + align:start position:0% +otherwise it's not going to work so a + + + align:start position:0% +otherwise it's not going to work so a +conjugate base of a strong acid is + + align:start position:0% +conjugate base of a strong acid is + + + align:start position:0% +conjugate base of a strong acid is +ineffective as a base and so if you add + + align:start position:0% +ineffective as a base and so if you add + + + align:start position:0% +ineffective as a base and so if you add +an acid it won't be neutralized and the + + align:start position:0% +an acid it won't be neutralized and the + + + align:start position:0% +an acid it won't be neutralized and the +pH will change so you need to have that + + align:start position:0% +pH will change so you need to have that + + + align:start position:0% +pH will change so you need to have that +conj something that works as a conjugate + + align:start position:0% +conj something that works as a conjugate + + + align:start position:0% +conj something that works as a conjugate +base something that's able to interact + + align:start position:0% +base something that's able to interact + + + align:start position:0% +base something that's able to interact +with the hydronium ion or the acid + + align:start position:0% +with the hydronium ion or the acid + + + align:start position:0% +with the hydronium ion or the acid +that's added and take its proton to + + align:start position:0% +that's added and take its proton to + + + align:start position:0% +that's added and take its proton to +neutralize it if this doesn't happen the + + align:start position:0% +neutralize it if this doesn't happen the + + + align:start position:0% +neutralize it if this doesn't happen the +pH will be affected so you need to have + + align:start position:0% +pH will be affected so you need to have + + + align:start position:0% +pH will be affected so you need to have +weak acids and weak bases in your + + align:start position:0% +weak acids and weak bases in your + + + align:start position:0% +weak acids and weak bases in your +buffers they could be moderately weak or + + align:start position:0% +buffers they could be moderately weak or + + + align:start position:0% +buffers they could be moderately weak or +very weak or whatever but they H you + + align:start position:0% +very weak or whatever but they H you + + + align:start position:0% +very weak or whatever but they H you +have to have a conjugate set that's + + align:start position:0% +have to have a conjugate set that's + + + align:start position:0% +have to have a conjugate set that's +going to be able to push push both + + align:start position:0% +going to be able to push push both + + + align:start position:0% +going to be able to push push both +directions where the acid can interact + + align:start position:0% +directions where the acid can interact + + + align:start position:0% +directions where the acid can interact +with the added base and the base can + + align:start position:0% +with the added base and the base can + + + align:start position:0% +with the added base and the base can +interact with the added acid all right + + align:start position:0% +interact with the added acid all right + + + align:start position:0% +interact with the added acid all right +so all of this is really the same for a + + align:start position:0% +so all of this is really the same for a + + + align:start position:0% +so all of this is really the same for a +basic um buffer so we can look at an + + align:start position:0% +basic um buffer so we can look at an + + + align:start position:0% +basic um buffer so we can look at an +example here of ammonia plus water going + + align:start position:0% +example here of ammonia plus water going + + + align:start position:0% +example here of ammonia plus water going +to ammonium ion and hydroxide ion and we + + align:start position:0% +to ammonium ion and hydroxide ion and we + + + align:start position:0% +to ammonium ion and hydroxide ion and we +can think about the same things when you + + align:start position:0% +can think about the same things when you + + + align:start position:0% +can think about the same things when you +add a strong acid the base will accept + + align:start position:0% +add a strong acid the base will accept + + + align:start position:0% +add a strong acid the base will accept +the protons and make more of your + + align:start position:0% +the protons and make more of your + + + align:start position:0% +the protons and make more of your +conjugate acid when a strong base is + + align:start position:0% +conjugate acid when a strong base is + + + align:start position:0% +conjugate acid when a strong base is +added the conjugate acid will donate its + + align:start position:0% +added the conjugate acid will donate its + + + align:start position:0% +added the conjugate acid will donate its +proton and it will form NH3 again that + + align:start position:0% +proton and it will form NH3 again that + + + align:start position:0% +proton and it will form NH3 again that +conjugate base and water and the pH will + + align:start position:0% +conjugate base and water and the pH will + + + align:start position:0% +conjugate base and water and the pH will +stay the same so it's a same idea the + + align:start position:0% +stay the same so it's a same idea the + + + align:start position:0% +stay the same so it's a same idea the +only real difference between an acidic + + align:start position:0% +only real difference between an acidic + + + align:start position:0% +only real difference between an acidic +buffer and a basic buffer is whether it + + align:start position:0% +buffer and a basic buffer is whether it + + + align:start position:0% +buffer and a basic buffer is whether it +phes in the acidic range or in the basic + + align:start position:0% +phes in the acidic range or in the basic + + + align:start position:0% +phes in the acidic range or in the basic +range but the buffers work the same way + + align:start position:0% +range but the buffers work the same way + + + align:start position:0% +range but the buffers work the same way +so I can redraw this picture + + align:start position:0% +so I can redraw this picture + + + align:start position:0% +so I can redraw this picture +um to have our different symbols on it + + align:start position:0% +um to have our different symbols on it + + + align:start position:0% +um to have our different symbols on it +but the idea is the same the weak base + + align:start position:0% +but the idea is the same the weak base + + + align:start position:0% +but the idea is the same the weak base +um will take the proton supplied by the + + align:start position:0% +um will take the proton supplied by the + + + align:start position:0% +um will take the proton supplied by the +acid and the conjugate acid + + align:start position:0% +acid and the conjugate acid + + + align:start position:0% +acid and the conjugate acid +bh+ is going to uh protonate the O minus + + align:start position:0% +bh+ is going to uh protonate the O minus + + + align:start position:0% +bh+ is going to uh protonate the O minus +and again keep the pH constant so the + + align:start position:0% +and again keep the pH constant so the + + + align:start position:0% +and again keep the pH constant so the +idea again of the buffer then is that a + + align:start position:0% +idea again of the buffer then is that a + + + align:start position:0% +idea again of the buffer then is that a +buffer is a mixture of weak conjugate + + align:start position:0% +buffer is a mixture of weak conjugate + + + align:start position:0% +buffer is a mixture of weak conjugate +acids and bases again they're weak + + align:start position:0% +acids and bases again they're weak + + + align:start position:0% +acids and bases again they're weak +because its partner needs to be + + align:start position:0% +because its partner needs to be + + + align:start position:0% +because its partner needs to be +effective as an acid or a base it can't + + align:start position:0% +effective as an acid or a base it can't + + + align:start position:0% +effective as an acid or a base it can't +be ineffective weak acidbase mixtures + + align:start position:0% +be ineffective weak acidbase mixtures + + + align:start position:0% +be ineffective weak acidbase mixtures +that stabilize pH by providing a source + + align:start position:0% +that stabilize pH by providing a source + + + align:start position:0% +that stabilize pH by providing a source +or a sync for protons it either adds + + align:start position:0% +or a sync for protons it either adds + + + align:start position:0% +or a sync for protons it either adds +protons or takes protons away it can + + align:start position:0% +protons or takes protons away it can + + + align:start position:0% +protons or takes protons away it can +respond to added acid it can respond to + + align:start position:0% +respond to added acid it can respond to + + + align:start position:0% +respond to added acid it can respond to +added + + align:start position:0% +added + + + align:start position:0% +added +base so again pH is important and + + align:start position:0% +base so again pH is important and + + + align:start position:0% +base so again pH is important and +buffering is + + align:start position:0% +buffering is + + + align:start position:0% +buffering is +important our body has its own buffer + + align:start position:0% +important our body has its own buffer + + + align:start position:0% +important our body has its own buffer +buffing system so we have carbonic acid + + align:start position:0% +buffing system so we have carbonic acid + + + align:start position:0% +buffing system so we have carbonic acid +and bicarbonate buffering agents in our + + align:start position:0% +and bicarbonate buffering agents in our + + + align:start position:0% +and bicarbonate buffering agents in our +blood and our blood has to be kept in + + align:start position:0% +blood and our blood has to be kept in + + + align:start position:0% +blood and our blood has to be kept in +this sort of neutral range over here if + + align:start position:0% +this sort of neutral range over here if + + + align:start position:0% +this sort of neutral range over here if +it gets to acidic um that is very + + align:start position:0% +it gets to acidic um that is very + + + align:start position:0% +it gets to acidic um that is very +unhealthy for us leading to some pretty + + align:start position:0% +unhealthy for us leading to some pretty + + + align:start position:0% +unhealthy for us leading to some pretty +severe symptoms um and too much leads to + + align:start position:0% +severe symptoms um and too much leads to + + + align:start position:0% +severe symptoms um and too much leads to +death if it's too basic that's really + + align:start position:0% +death if it's too basic that's really + + + align:start position:0% +death if it's too basic that's really +bad also we have death and notice these + + align:start position:0% +bad also we have death and notice these + + + align:start position:0% +bad also we have death and notice these +are not all that far away there are a + + align:start position:0% +are not all that far away there are a + + + align:start position:0% +are not all that far away there are a +number of different medical conditions + + align:start position:0% +number of different medical conditions + + + align:start position:0% +number of different medical conditions +that can affect the pH diabetes their + + align:start position:0% +that can affect the pH diabetes their + + + align:start position:0% +that can affect the pH diabetes their +metabolic diseases something else that + + align:start position:0% +metabolic diseases something else that + + + align:start position:0% +metabolic diseases something else that +is under your + + align:start position:0% +is under your + + + align:start position:0% +is under your +control hydration you need to drink + + align:start position:0% +control hydration you need to drink + + + align:start position:0% +control hydration you need to drink +enough water and as the weather gets + + align:start position:0% +enough water and as the weather gets + + + align:start position:0% +enough water and as the weather gets +colder in Boston people often stop + + align:start position:0% +colder in Boston people often stop + + + align:start position:0% +colder in Boston people often stop +drinking as much water or start drinking + + align:start position:0% +drinking as much water or start drinking + + + align:start position:0% +drinking as much water or start drinking +like hot beverages which don't hydrate + + align:start position:0% +like hot beverages which don't hydrate + + + align:start position:0% +like hot beverages which don't hydrate +as well so keep hydrated if you're not + + align:start position:0% +as well so keep hydrated if you're not + + + align:start position:0% +as well so keep hydrated if you're not +hydrated you can if it's gets really bad + + align:start position:0% +hydrated you can if it's gets really bad + + + align:start position:0% +hydrated you can if it's gets really bad +it can start affecting the pH of your + + align:start position:0% +it can start affecting the pH of your + + + align:start position:0% +it can start affecting the pH of your +blood which is really not good so + + align:start position:0% +blood which is really not good so + + + align:start position:0% +blood which is really not good so +buffering very + + align:start position:0% +buffering very + + + align:start position:0% +buffering very +important all right so let's do a sample + + align:start position:0% +important all right so let's do a sample + + + align:start position:0% +important all right so let's do a sample +buffer + + align:start position:0% +buffer + + + align:start position:0% +buffer +problem so sample buffer problem and + + align:start position:0% +problem so sample buffer problem and + + + align:start position:0% +problem so sample buffer problem and +this is important I actually know of at + + align:start position:0% +this is important I actually know of at + + + align:start position:0% +this is important I actually know of at +least one Professor that if you want to + + align:start position:0% +least one Professor that if you want to + + + align:start position:0% +least one Professor that if you want to +do a europ with them they'll come to + + align:start position:0% +do a europ with them they'll come to + + + align:start position:0% +do a europ with them they'll come to +their office and they're going to say + + align:start position:0% +their office and they're going to say + + + align:start position:0% +their office and they're going to say +all right write down how you would + + align:start position:0% +all right write down how you would + + + align:start position:0% +all right write down how you would +design a buffer for me and do those + + align:start position:0% +design a buffer for me and do those + + + align:start position:0% +design a buffer for me and do those +calculations so I can tell you later who + + align:start position:0% +calculations so I can tell you later who + + + align:start position:0% +calculations so I can tell you later who +that is maybe I won't I don't know but + + align:start position:0% +that is maybe I won't I don't know but + + + align:start position:0% +that is maybe I won't I don't know but +this is one of the tests that someone + + align:start position:0% +this is one of the tests that someone + + + align:start position:0% +this is one of the tests that someone +uses to see if they want you as a EUR + + align:start position:0% +uses to see if they want you as a EUR + + + align:start position:0% +uses to see if they want you as a EUR +up okay so here we have one mole of + + align:start position:0% +up okay so here we have one mole of + + + align:start position:0% +up okay so here we have one mole of +formic acid and 0.5 moles of the + + align:start position:0% +formic acid and 0.5 moles of the + + + align:start position:0% +formic acid and 0.5 moles of the +conjugate base supplied in the form of a + + align:start position:0% +conjugate base supplied in the form of a + + + align:start position:0% +conjugate base supplied in the form of a +salt with sodium ions and those are + + align:start position:0% +salt with sodium ions and those are + + + align:start position:0% +salt with sodium ions and those are +added to water and diluted to a total + + align:start position:0% +added to water and diluted to a total + + + align:start position:0% +added to water and diluted to a total +final concentration of one liter and + + align:start position:0% +final concentration of one liter and + + + align:start position:0% +final concentration of one liter and +you're given the uh Ka and told to + + align:start position:0% +you're given the uh Ka and told to + + + align:start position:0% +you're given the uh Ka and told to +calculate the pH so the first step is to + + align:start position:0% +calculate the pH so the first step is to + + + align:start position:0% +calculate the pH so the first step is to +write out the equation so we have um an + + align:start position:0% +write out the equation so we have um an + + + align:start position:0% +write out the equation so we have um an +acid in water going to hydronium ions + + align:start position:0% +acid in water going to hydronium ions + + + align:start position:0% +acid in water going to hydronium ions +and a conjugate base over here and we + + align:start position:0% +and a conjugate base over here and we + + + align:start position:0% +and a conjugate base over here and we +want to think about what's there now + + align:start position:0% +want to think about what's there now + + + align:start position:0% +want to think about what's there now +what's it and what's at + + align:start position:0% +what's it and what's at + + + align:start position:0% +what's it and what's at +equilibrium so initial marity change in + + align:start position:0% +equilibrium so initial marity change in + + + align:start position:0% +equilibrium so initial marity change in +marity and your equilibrium marity so + + align:start position:0% +marity and your equilibrium marity so + + + align:start position:0% +marity and your equilibrium marity so +it's important this word marity don't + + align:start position:0% +it's important this word marity don't + + + align:start position:0% +it's important this word marity don't +put put moles in here put marity in here + + align:start position:0% +put put moles in here put marity in here + + + align:start position:0% +put put moles in here put marity in here +but I made it really easy for you + + align:start position:0% +but I made it really easy for you + + + align:start position:0% +but I made it really easy for you +because we have one mole in one liter so + + align:start position:0% +because we have one mole in one liter so + + + align:start position:0% +because we have one mole in one liter so +the marity is one 0.5 moles in one liter + + align:start position:0% +the marity is one 0.5 moles in one liter + + + align:start position:0% +the marity is one 0.5 moles in one liter +the marity is + + align:start position:0% +the marity is + + + align:start position:0% +the marity is +0.5 and this is also really important + + align:start position:0% +0.5 and this is also really important + + + align:start position:0% +0.5 and this is also really important +you're so used to only putting things + + align:start position:0% +you're so used to only putting things + + + align:start position:0% +you're so used to only putting things +here when it's a buffer problem you got + + align:start position:0% +here when it's a buffer problem you got + + + align:start position:0% +here when it's a buffer problem you got +to put something here too so you're + + align:start position:0% +to put something here too so you're + + + align:start position:0% +to put something here too so you're +adding the acid with the conjugate base + + align:start position:0% +adding the acid with the conjugate base + + + align:start position:0% +adding the acid with the conjugate base +at the same time this is not zero + + align:start position:0% +at the same time this is not zero + + + align:start position:0% +at the same time this is not zero +this is + + align:start position:0% +this is + + + align:start position:0% +this is +0.5 so now as this dynamic equilibrium + + align:start position:0% +0.5 so now as this dynamic equilibrium + + + align:start position:0% +0.5 so now as this dynamic equilibrium +goes you're losing some of this and + + align:start position:0% +goes you're losing some of this and + + + align:start position:0% +goes you're losing some of this and +gaining some of + + align:start position:0% +gaining some of + + + align:start position:0% +gaining some of +these so at equilibrium we have 1 molar + + align:start position:0% +these so at equilibrium we have 1 molar + + + align:start position:0% +these so at equilibrium we have 1 molar +minus x x is our hydronium ion + + align:start position:0% +minus x x is our hydronium ion + + + align:start position:0% +minus x x is our hydronium ion +concentration which is what we want to + + align:start position:0% +concentration which is what we want to + + + align:start position:0% +concentration which is what we want to +know to calculate pH and our conjugate + + align:start position:0% +know to calculate pH and our conjugate + + + align:start position:0% +know to calculate pH and our conjugate +base our formate formate ion is .5 plus + + align:start position:0% +base our formate formate ion is .5 plus + + + align:start position:0% +base our formate formate ion is .5 plus +X we're given a k a and we've written + + align:start position:0% +X we're given a k a and we've written + + + align:start position:0% +X we're given a k a and we've written +this expression as a acid in water so we + + align:start position:0% +this expression as a acid in water so we + + + align:start position:0% +this expression as a acid in water so we +can use Ka the equilibrium constant is + + align:start position:0% +can use Ka the equilibrium constant is + + + align:start position:0% +can use Ka the equilibrium constant is +for the expression as written so we can + + align:start position:0% +for the expression as written so we can + + + align:start position:0% +for the expression as written so we can +put that in and we can uh + + align:start position:0% +put that in and we can uh + + + align:start position:0% +put that in and we can uh +Supply um the uh fill the rest out we + + align:start position:0% +Supply um the uh fill the rest out we + + + align:start position:0% +Supply um the uh fill the rest out we +have our products we have the + + align:start position:0% +have our products we have the + + + align:start position:0% +have our products we have the +concentration of hydronium ion times the + + align:start position:0% +concentration of hydronium ion times the + + + align:start position:0% +concentration of hydronium ion times the +concentration of formate ion the + + align:start position:0% +concentration of formate ion the + + + align:start position:0% +concentration of formate ion the +conjugate base over the concentration of + + align:start position:0% +conjugate base over the concentration of + + + align:start position:0% +conjugate base over the concentration of +our formic acid and again again water + + align:start position:0% +our formic acid and again again water + + + align:start position:0% +our formic acid and again again water +does not appear in the expression + + align:start position:0% +does not appear in the expression + + + align:start position:0% +does not appear in the expression +because it's the solvent hydronium ion + + align:start position:0% +because it's the solvent hydronium ion + + + align:start position:0% +because it's the solvent hydronium ion +concentration is X the conjugate base + + align:start position:0% +concentration is X the conjugate base + + + align:start position:0% +concentration is X the conjugate base +concentration is05 + x and the conjugate + + align:start position:0% +concentration is05 + x and the conjugate + + + align:start position:0% +concentration is05 + x and the conjugate +acid concentration is 1 - + + align:start position:0% +acid concentration is 1 - + + + align:start position:0% +acid concentration is 1 - +x so we can now try that assumption that + + align:start position:0% +x so we can now try that assumption that + + + align:start position:0% +x so we can now try that assumption that +X is small or we can use the quadratic + + align:start position:0% +X is small or we can use the quadratic + + + align:start position:0% +X is small or we can use the quadratic +equation but why don't you just uh try + + align:start position:0% +equation but why don't you just uh try + + + align:start position:0% +equation but why don't you just uh try +that assumption I'm going to take this + + align:start position:0% +that assumption I'm going to take this + + + align:start position:0% +that assumption I'm going to take this +expression if you haven't written it all + + align:start position:0% +expression if you haven't written it all + + + align:start position:0% +expression if you haven't written it all +down yet put it right up here and now + + align:start position:0% +down yet put it right up here and now + + + align:start position:0% +down yet put it right up here and now +with a clicker why don't you tell me if + + align:start position:0% +with a clicker why don't you tell me if + + + align:start position:0% +with a clicker why don't you tell me if +we use the approximation that X is small + + align:start position:0% +we use the approximation that X is small + + + align:start position:0% +we use the approximation that X is small +compared to 1 in 0.5 what does this + + align:start position:0% +compared to 1 in 0.5 what does this + + + align:start position:0% +compared to 1 in 0.5 what does this +simplify + + align:start position:0% + + + + align:start position:0% + +to all right 10 more seconds + + align:start position:0% + + + + align:start position:0% + +all right so 70 uh something percent yep + + align:start position:0% +all right so 70 uh something percent yep + + + align:start position:0% +all right so 70 uh something percent yep +so let's take a look at + + align:start position:0% +so let's take a look at + + + align:start position:0% +so let's take a look at +that so here we're making the assumption + + align:start position:0% +that so here we're making the assumption + + + align:start position:0% +that so here we're making the assumption +that X is small compared to 0.5 and + + align:start position:0% +that X is small compared to 0.5 and + + + align:start position:0% +that X is small compared to 0.5 and +compared to one so that means that we + + align:start position:0% +compared to one so that means that we + + + align:start position:0% +compared to one so that means that we +draw drop the plus X from the 0.5 term + + align:start position:0% +draw drop the plus X from the 0.5 term + + + align:start position:0% +draw drop the plus X from the 0.5 term +and drop the minus X from the one term + + align:start position:0% +and drop the minus X from the one term + + + align:start position:0% +and drop the minus X from the one term +so we're saying that these are going to + + align:start position:0% +so we're saying that these are going to + + + align:start position:0% +so we're saying that these are going to +be small enough that it's still going to + + align:start position:0% +be small enough that it's still going to + + + align:start position:0% +be small enough that it's still going to +be pretty much 05 and one and then we + + align:start position:0% +be pretty much 05 and one and then we + + + align:start position:0% +be pretty much 05 and one and then we +have to test that in a minute so if we + + align:start position:0% +have to test that in a minute so if we + + + align:start position:0% +have to test that in a minute so if we +use this we can calculate X and it comes + + align:start position:0% +use this we can calculate X and it comes + + + align:start position:0% +use this we can calculate X and it comes +out to 3.54 * + + align:start position:0% +out to 3.54 * + + + align:start position:0% +out to 3.54 * +10-4 and then we can check the + + align:start position:0% +10-4 and then we can check the + + + align:start position:0% +10-4 and then we can check the +Assumption and before you told me how to + + align:start position:0% +Assumption and before you told me how to + + + align:start position:0% +Assumption and before you told me how to +check assumptions um um and that was I + + align:start position:0% +check assumptions um um and that was I + + + align:start position:0% +check assumptions um um and that was I +take X and I'll divide it by 0.5 which + + align:start position:0% +take X and I'll divide it by 0.5 which + + + align:start position:0% +take X and I'll divide it by 0.5 which +is the smaller of these two um and Times + + align:start position:0% +is the smaller of these two um and Times + + + align:start position:0% +is the smaller of these two um and Times +by 100% And we get + + align:start position:0% +by 100% And we get + + + align:start position:0% +by 100% And we get +0.69% Which is less than 5% so the + + align:start position:0% +0.69% Which is less than 5% so the + + + align:start position:0% +0.69% Which is less than 5% so the +assumption is okay um and we don't have + + align:start position:0% +assumption is okay um and we don't have + + + align:start position:0% +assumption is okay um and we don't have +to check it against one because if the + + align:start position:0% +to check it against one because if the + + + align:start position:0% +to check it against one because if the +Assumption X is small compared to the + + align:start position:0% +Assumption X is small compared to the + + + align:start position:0% +Assumption X is small compared to the +smaller number is valid it'll also be + + align:start position:0% +smaller number is valid it'll also be + + + align:start position:0% +smaller number is valid it'll also be +valid for the bigger number so you only + + align:start position:0% +valid for the bigger number so you only + + + align:start position:0% +valid for the bigger number so you only +check it for the smaller number and then + + align:start position:0% +check it for the smaller number and then + + + align:start position:0% +check it for the smaller number and then +we can + + align:start position:0% +we can + + + align:start position:0% +we can +um solve so we have to think about we + + align:start position:0% +um solve so we have to think about we + + + align:start position:0% +um solve so we have to think about we +solve for x we're happy with X our + + align:start position:0% +solve for x we're happy with X our + + + align:start position:0% +solve for x we're happy with X our +assumption was okay but then we have to + + align:start position:0% +assumption was okay but then we have to + + + align:start position:0% +assumption was okay but then we have to +remember what x is and X is the + + align:start position:0% +remember what x is and X is the + + + align:start position:0% +remember what x is and X is the +hydronium ion + + align:start position:0% +hydronium ion + + + align:start position:0% +hydronium ion +concentration and you always want to + + align:start position:0% +concentration and you always want to + + + align:start position:0% +concentration and you always want to +make sure to think about this because if + + align:start position:0% +make sure to think about this because if + + + align:start position:0% +make sure to think about this because if +it's hydroxide ion that's different so + + align:start position:0% +it's hydroxide ion that's different so + + + align:start position:0% +it's hydroxide ion that's different so +we can calculate pH pH is minus log of + + align:start position:0% +we can calculate pH pH is minus log of + + + align:start position:0% +we can calculate pH pH is minus log of +3.54 * 10- 4 which is equal to pH of + + align:start position:0% +3.54 * 10- 4 which is equal to pH of + + + align:start position:0% +3.54 * 10- 4 which is equal to pH of +3.45 + + align:start position:0% +3.45 + + + align:start position:0% +3.45 +five and here we have two significant + + align:start position:0% +five and here we have two significant + + + align:start position:0% +five and here we have two significant +figures after the decimal point because + + align:start position:0% +figures after the decimal point because + + + align:start position:0% +figures after the decimal point because +the volume we had before only had two + + align:start position:0% +the volume we had before only had two + + + align:start position:0% +the volume we had before only had two +significant figures everything else had + + align:start position:0% +significant figures everything else had + + + align:start position:0% +significant figures everything else had +three but the volume was just 1.0 so + + align:start position:0% +three but the volume was just 1.0 so + + + align:start position:0% +three but the volume was just 1.0 so +that is our answer there all right so + + align:start position:0% +that is our answer there all right so + + + align:start position:0% +that is our answer there all right so +I'm going to um just briefly um start + + align:start position:0% +I'm going to um just briefly um start + + + align:start position:0% +I'm going to um just briefly um start +what happens well actually we'll do + + align:start position:0% +what happens well actually we'll do + + + align:start position:0% +what happens well actually we'll do +we'll do next this is how you would + + align:start position:0% +we'll do next this is how you would + + + align:start position:0% +we'll do next this is how you would +design the buffer for this next time + + align:start position:0% +design the buffer for this next time + + + align:start position:0% +design the buffer for this next time +we'll see what happens if we stress the + + align:start position:0% +we'll see what happens if we stress the + + + align:start position:0% +we'll see what happens if we stress the +buffer we designed + + align:start position:0% +buffer we designed + + + align:start position:0% +buffer we designed +by adding acid to it and see what the + + align:start position:0% +by adding acid to it and see what the + + + align:start position:0% +by adding acid to it and see what the +new result + + align:start position:0% +new result + + + align:start position:0% +new result +is all right so today we're going to + + align:start position:0% +is all right so today we're going to + + + align:start position:0% +is all right so today we're going to +finish uh lecture 22 so take out those + + align:start position:0% +finish uh lecture 22 so take out those + + + align:start position:0% +finish uh lecture 22 so take out those +lecture notes and uh on acids and bases + + align:start position:0% +lecture notes and uh on acids and bases + + + align:start position:0% +lecture notes and uh on acids and bases +and when we're done with that we'll just + + align:start position:0% +and when we're done with that we'll just + + + align:start position:0% +and when we're done with that we'll just +continue with acids and bases and we're + + align:start position:0% +continue with acids and bases and we're + + + align:start position:0% +continue with acids and bases and we're +going to continue with some acids and + + align:start position:0% +going to continue with some acids and + + + align:start position:0% +going to continue with some acids and +bases on Wednesday but we should finish + + align:start position:0% +bases on Wednesday but we should finish + + + align:start position:0% +bases on Wednesday but we should finish +on Wednesday and move on to oxidation + + align:start position:0% +on Wednesday and move on to oxidation + + + align:start position:0% +on Wednesday and move on to oxidation +reduction um and that will end exam 3 + + align:start position:0% +reduction um and that will end exam 3 + + + align:start position:0% +reduction um and that will end exam 3 +material so uh exam 3 is sneaking up on + + align:start position:0% +material so uh exam 3 is sneaking up on + + + align:start position:0% +material so uh exam 3 is sneaking up on +us and it'll have thermodynamics + + align:start position:0% +us and it'll have thermodynamics + + + align:start position:0% +us and it'll have thermodynamics +chemical equilibrium solubility and acid + + align:start position:0% + + + + align:start position:0% + +base all right so you should have + + align:start position:0% +base all right so you should have + + + align:start position:0% +base all right so you should have +already filled in your handout with all + + align:start position:0% +already filled in your handout with all + + + align:start position:0% +already filled in your handout with all +the information the parts that you uh + + align:start position:0% +the information the parts that you uh + + + align:start position:0% +the information the parts that you uh +we're filling in are uh in in bold here + + align:start position:0% +we're filling in are uh in in bold here + + + align:start position:0% +we're filling in are uh in in bold here +but I just want to remind you of what we + + align:start position:0% +but I just want to remind you of what we + + + align:start position:0% +but I just want to remind you of what we +were talking about so we had a sample + + align:start position:0% +were talking about so we had a sample + + + align:start position:0% +were talking about so we had a sample +buffer problem we had one mole of a + + align:start position:0% +buffer problem we had one mole of a + + + align:start position:0% +buffer problem we had one mole of a +conjugate acid and a half a mole of a + + align:start position:0% +conjugate acid and a half a mole of a + + + align:start position:0% +conjugate acid and a half a mole of a +con of its conjugate base supplied in + + align:start position:0% +con of its conjugate base supplied in + + + align:start position:0% +con of its conjugate base supplied in +the form of a salt were put in water and + + align:start position:0% +the form of a salt were put in water and + + + align:start position:0% +the form of a salt were put in water and +diluted to one to one liter so we + + align:start position:0% +diluted to one to one liter so we + + + align:start position:0% +diluted to one to one liter so we +calculated what um the hydronium ion + + align:start position:0% +calculated what um the hydronium ion + + + align:start position:0% +calculated what um the hydronium ion +concentration would be and therefore the + + align:start position:0% +concentration would be and therefore the + + + align:start position:0% +concentration would be and therefore the +pH using information that was given to + + align:start position:0% +pH using information that was given to + + + align:start position:0% +pH using information that was given to +us about the KA the acid ionization + + align:start position:0% +us about the KA the acid ionization + + + align:start position:0% +us about the KA the acid ionization +constant so um we got a pH of + + align:start position:0% +constant so um we got a pH of + + + align:start position:0% +constant so um we got a pH of +3.45 um someone asked me after class but + + align:start position:0% +3.45 um someone asked me after class but + + + align:start position:0% +3.45 um someone asked me after class but +isn't this conjugate base also reacting + + align:start position:0% +isn't this conjugate base also reacting + + + align:start position:0% +isn't this conjugate base also reacting +with water and forming some of this uh + + align:start position:0% +with water and forming some of this uh + + + align:start position:0% +with water and forming some of this uh +weak acid and the answer is yes um that + + align:start position:0% +weak acid and the answer is yes um that + + + align:start position:0% +weak acid and the answer is yes um that +we are writing this as a problem of acid + + align:start position:0% +we are writing this as a problem of acid + + + align:start position:0% +we are writing this as a problem of acid +in water because we can use the KA but + + align:start position:0% +in water because we can use the KA but + + + align:start position:0% +in water because we can use the KA but +we could have also written it the other + + align:start position:0% +we could have also written it the other + + + align:start position:0% +we could have also written it the other +way and written it and this is not in + + align:start position:0% +way and written it and this is not in + + + align:start position:0% +way and written it and this is not in +your notes but I just want to let you + + align:start position:0% +your notes but I just want to let you + + + align:start position:0% +your notes but I just want to let you +know um that the weak base in water + + align:start position:0% +know um that the weak base in water + + + align:start position:0% +know um that the weak base in water +could be written that way forming a + + align:start position:0% +could be written that way forming a + + + align:start position:0% +could be written that way forming a +conjugate acid and um hydroxide ions and + + align:start position:0% +conjugate acid and um hydroxide ions and + + + align:start position:0% +conjugate acid and um hydroxide ions and +so then it would be5 Min - x and 1 + x + + align:start position:0% +so then it would be5 Min - x and 1 + x + + + align:start position:0% +so then it would be5 Min - x and 1 + x +and x use KB then because it's a base in + + align:start position:0% +and x use KB then because it's a base in + + + align:start position:0% +and x use KB then because it's a base in +water to solve for x and calculate pH + + align:start position:0% +water to solve for x and calculate pH + + + align:start position:0% +water to solve for x and calculate pH +from p and if you try it you get + + align:start position:0% +from p and if you try it you get + + + align:start position:0% +from p and if you try it you get +3.45 so you can do these problems either + + align:start position:0% +3.45 so you can do these problems either + + + align:start position:0% +3.45 so you can do these problems either +way you can think about them as a weak + + align:start position:0% +way you can think about them as a weak + + + align:start position:0% +way you can think about them as a weak +base problem or a weak acid problem you + + align:start position:0% +base problem or a weak acid problem you + + + align:start position:0% +base problem or a weak acid problem you +just have to remember that there's if + + align:start position:0% +just have to remember that there's if + + + align:start position:0% +just have to remember that there's if +this is not zero when you start the uh + + align:start position:0% +this is not zero when you start the uh + + + align:start position:0% +this is not zero when you start the uh +the conjugate has some amount that's + + align:start position:0% +the conjugate has some amount that's + + + align:start position:0% +the conjugate has some amount that's +what makes it a good buffer so this can + + align:start position:0% +what makes it a good buffer so this can + + + align:start position:0% +what makes it a good buffer so this can +work either way but you also want to + + align:start position:0% +work either way but you also want to + + + align:start position:0% +work either way but you also want to +remember if you write it as an acid in + + align:start position:0% +remember if you write it as an acid in + + + align:start position:0% +remember if you write it as an acid in +water use Ka if you write it as a base + + align:start position:0% +water use Ka if you write it as a base + + + align:start position:0% +water use Ka if you write it as a base +in water use KB because those + + align:start position:0% +in water use KB because those + + + align:start position:0% +in water use KB because those +equilibrium constants are telling you + + align:start position:0% +equilibrium constants are telling you + + + align:start position:0% +equilibrium constants are telling you +about those ratios of the conjugate acid + + align:start position:0% +about those ratios of the conjugate acid + + + align:start position:0% +about those ratios of the conjugate acid +and the conjugate base at equilibrium So + + align:start position:0% +and the conjugate base at equilibrium So + + + align:start position:0% +and the conjugate base at equilibrium So +within the KA and the KB is information + + align:start position:0% +within the KA and the KB is information + + + align:start position:0% +within the KA and the KB is information +that you need about this Dynamic + + align:start position:0% +that you need about this Dynamic + + + align:start position:0% +that you need about this Dynamic +chemical equilibrium so both of these + + align:start position:0% +chemical equilibrium so both of these + + + align:start position:0% +chemical equilibrium so both of these +Ways work and by the end of sort of + + align:start position:0% +Ways work and by the end of sort of + + + align:start position:0% +Ways work and by the end of sort of +halfway through today's lecture you'll + + align:start position:0% +halfway through today's lecture you'll + + + align:start position:0% +halfway through today's lecture you'll +see yet another way to solve buffer + + align:start position:0% +see yet another way to solve buffer + + + align:start position:0% +see yet another way to solve buffer +problems and probably will be for most + + align:start position:0% +problems and probably will be for most + + + align:start position:0% +problems and probably will be for most +of you the preferred way to do it so + + align:start position:0% +of you the preferred way to do it so + + + align:start position:0% +of you the preferred way to do it so +there's a number of different ways which + + align:start position:0% +there's a number of different ways which + + + align:start position:0% +there's a number of different ways which +makes grading the exam lots of fun um + + align:start position:0% +makes grading the exam lots of fun um + + + align:start position:0% +makes grading the exam lots of fun um +and we have option one option two option + + align:start position:0% +and we have option one option two option + + + align:start position:0% +and we have option one option two option +three um to make sure that uh that that + + align:start position:0% +three um to make sure that uh that that + + + align:start position:0% +three um to make sure that uh that that +all the options are are possibly + + align:start position:0% +all the options are are possibly + + + align:start position:0% +all the options are are possibly +accounted for all right so the purpose + + align:start position:0% +accounted for all right so the purpose + + + align:start position:0% +accounted for all right so the purpose +of a buffer is to keep the pH pretty + + align:start position:0% +of a buffer is to keep the pH pretty + + + align:start position:0% +of a buffer is to keep the pH pretty +much constant so you can add a strong + + align:start position:0% +much constant so you can add a strong + + + align:start position:0% +much constant so you can add a strong +acid to it and the acid will be + + align:start position:0% +acid to it and the acid will be + + + align:start position:0% +acid to it and the acid will be +neutralized um keeping the pH const you + + align:start position:0% +neutralized um keeping the pH const you + + + align:start position:0% +neutralized um keeping the pH const you +can add a strong base to it and the base + + align:start position:0% +can add a strong base to it and the base + + + align:start position:0% +can add a strong base to it and the base +will be neutralized keeping the pH + + align:start position:0% +will be neutralized keeping the pH + + + align:start position:0% +will be neutralized keeping the pH +pretty constant so what you want in a + + align:start position:0% +pretty constant so what you want in a + + + align:start position:0% +pretty constant so what you want in a +buffer is to have a weak acid conjugate + + align:start position:0% +buffer is to have a weak acid conjugate + + + align:start position:0% +buffer is to have a weak acid conjugate +base pairing that allows it to be a + + align:start position:0% +base pairing that allows it to be a + + + align:start position:0% +base pairing that allows it to be a +source or sync for a strong acid or a + + align:start position:0% +source or sync for a strong acid or a + + + align:start position:0% +source or sync for a strong acid or a +strong base to keep the pH constant so + + align:start position:0% +strong base to keep the pH constant so + + + align:start position:0% +strong base to keep the pH constant so +now in this problem we're asked to + + align:start position:0% +now in this problem we're asked to + + + align:start position:0% +now in this problem we're asked to +calculate what would happen to the pH if + + align:start position:0% +calculate what would happen to the pH if + + + align:start position:0% +calculate what would happen to the pH if +0.1 moles of a strong acid had been + + align:start position:0% +0.1 moles of a strong acid had been + + + align:start position:0% +0.1 moles of a strong acid had been +included in our one um liter + + align:start position:0% +included in our one um liter + + + align:start position:0% +included in our one um liter +solution and and because 0.1 moles of + + align:start position:0% +solution and and because 0.1 moles of + + + align:start position:0% +solution and and because 0.1 moles of +our strong acid would react with equal + + align:start position:0% +our strong acid would react with equal + + + align:start position:0% +our strong acid would react with equal +number of moles of that conjugate base + + align:start position:0% +number of moles of that conjugate base + + + align:start position:0% +number of moles of that conjugate base +that's what the conjugate base does in a + + align:start position:0% +that's what the conjugate base does in a + + + align:start position:0% +that's what the conjugate base does in a +buffer it reacts with a strong acid that + + align:start position:0% +buffer it reacts with a strong acid that + + + align:start position:0% +buffer it reacts with a strong acid that +is supplied and it will form equal moles + + align:start position:0% +is supplied and it will form equal moles + + + align:start position:0% +is supplied and it will form equal moles +then of the uh the conjugate its + + align:start position:0% +then of the uh the conjugate its + + + align:start position:0% +then of the uh the conjugate its +conjugate acid so we have to do some + + align:start position:0% +conjugate acid so we have to do some + + + align:start position:0% +conjugate acid so we have to do some +subtraction so for the conjugate acid we + + align:start position:0% +subtraction so for the conjugate acid we + + + align:start position:0% +subtraction so for the conjugate acid we +had .5 moles and um and or sorry for the + + align:start position:0% +had .5 moles and um and or sorry for the + + + align:start position:0% +had .5 moles and um and or sorry for the +for the conjugate base we had 0. five + + align:start position:0% +for the conjugate base we had 0. five + + + align:start position:0% +for the conjugate base we had 0. five +moles we used up one of that 0 one of + + align:start position:0% +moles we used up one of that 0 one of + + + align:start position:0% +moles we used up one of that 0 one of +that reacting with a strong acid and we + + align:start position:0% +that reacting with a strong acid and we + + + align:start position:0% +that reacting with a strong acid and we +have 04 left so we have a new + + align:start position:0% +have 04 left so we have a new + + + align:start position:0% +have 04 left so we have a new +concentration for our conjugate + + align:start position:0% +concentration for our conjugate + + + align:start position:0% +concentration for our conjugate +base4 / 1 keep the mass + + align:start position:0% +base4 / 1 keep the mass + + + align:start position:0% +base4 / 1 keep the mass +simple4 + + align:start position:0% +simple4 + + + align:start position:0% +simple4 +molar so for our conjugate acid we had + + align:start position:0% +molar so for our conjugate acid we had + + + align:start position:0% +molar so for our conjugate acid we had +one mole to begin with but we formed 0.1 + + align:start position:0% +one mole to begin with but we formed 0.1 + + + align:start position:0% +one mole to begin with but we formed 0.1 +more + + align:start position:0% +more + + + align:start position:0% +more +when that strong acid was added so now + + align:start position:0% +when that strong acid was added so now + + + align:start position:0% +when that strong acid was added so now +we have 1.1 moles and a new + + align:start position:0% +we have 1.1 moles and a new + + + align:start position:0% +we have 1.1 moles and a new +marity so now we have to go back and we + + align:start position:0% +marity so now we have to go back and we + + + align:start position:0% +marity so now we have to go back and we +can use this expression again and + + align:start position:0% +can use this expression again and + + + align:start position:0% +can use this expression again and +determine what x is now what the + + align:start position:0% +determine what x is now what the + + + align:start position:0% +determine what x is now what the +hydronium ion concentration is now using + + align:start position:0% +hydronium ion concentration is now using + + + align:start position:0% +hydronium ion concentration is now using +Ka so why don't you tell me how um I + + align:start position:0% +Ka so why don't you tell me how um I + + + align:start position:0% +Ka so why don't you tell me how um I +would solve this what is the correct + + align:start position:0% +would solve this what is the correct + + + align:start position:0% +would solve this what is the correct +expression for KA and you can fill in + + align:start position:0% +expression for KA and you can fill in + + + align:start position:0% +expression for KA and you can fill in +your little table as you do it + + align:start position:0% + + + + align:start position:0% + +all right let's just do 10 more + + align:start position:0% + + + + align:start position:0% + +seconds all right so so let's just uh + + align:start position:0% +seconds all right so so let's just uh + + + align:start position:0% +seconds all right so so let's just uh +fill in that table if you haven't + + align:start position:0% +fill in that table if you haven't + + + align:start position:0% +fill in that table if you haven't +already so here now we can write this as + + align:start position:0% +already so here now we can write this as + + + align:start position:0% +already so here now we can write this as +an acid and water problem again again + + align:start position:0% +an acid and water problem again again + + + align:start position:0% +an acid and water problem again again +you could have done the base and water + + align:start position:0% +you could have done the base and water + + + align:start position:0% +you could have done the base and water +and use KB um but we'll just do it the + + align:start position:0% +and use KB um but we'll just do it the + + + align:start position:0% +and use KB um but we'll just do it the +same way we did before so we have our + + align:start position:0% +same way we did before so we have our + + + align:start position:0% +same way we did before so we have our +acid + + align:start position:0% +acid + + + align:start position:0% +acid +1.1 molar now remember this is marity so + + align:start position:0% +1.1 molar now remember this is marity so + + + align:start position:0% +1.1 molar now remember this is marity so +you don't want to put moles in here you + + align:start position:0% +you don't want to put moles in here you + + + align:start position:0% +you don't want to put moles in here you +want to put a concentration and some of + + align:start position:0% +want to put a concentration and some of + + + align:start position:0% +want to put a concentration and some of +that will be minus X then we have our + + align:start position:0% +that will be minus X then we have our + + + align:start position:0% +that will be minus X then we have our +044 plus X we can fill out the KA the KA + + align:start position:0% +044 plus X we can fill out the KA the KA + + + align:start position:0% +044 plus X we can fill out the KA the KA +again weak acid and water problem we + + align:start position:0% +again weak acid and water problem we + + + align:start position:0% +again weak acid and water problem we +have products hydronium ion over our our + + align:start position:0% +have products hydronium ion over our our + + + align:start position:0% +have products hydronium ion over our our +times our conjugate base over our + + align:start position:0% +times our conjugate base over our + + + align:start position:0% +times our conjugate base over our +conjugate acid equals 4 + x * X these + + align:start position:0% +conjugate acid equals 4 + x * X these + + + align:start position:0% +conjugate acid equals 4 + x * X these +two and 1.1 minus X on the + + align:start position:0% +two and 1.1 minus X on the + + + align:start position:0% +two and 1.1 minus X on the +bottom so you can always solve then for + + align:start position:0% +bottom so you can always solve then for + + + align:start position:0% +bottom so you can always solve then for +X which will tell you about the pH by + + align:start position:0% +X which will tell you about the pH by + + + align:start position:0% +X which will tell you about the pH by +using the KA and you just have to + + align:start position:0% +using the KA and you just have to + + + align:start position:0% +using the KA and you just have to +remember marity and remember these are + + align:start position:0% +remember marity and remember these are + + + align:start position:0% +remember marity and remember these are +the new marity after the reaction has + + align:start position:0% +the new marity after the reaction has + + + align:start position:0% +the new marity after the reaction has +occurred all right so we can use the um + + align:start position:0% +occurred all right so we can use the um + + + align:start position:0% +occurred all right so we can use the um +the approximation that X is small + + align:start position:0% +the approximation that X is small + + + align:start position:0% +the approximation that X is small +compared to 1.1 and4 to simplify this or + + align:start position:0% +compared to 1.1 and4 to simplify this or + + + align:start position:0% +compared to 1.1 and4 to simplify this or +we could use the quadratic equation if + + align:start position:0% +we could use the quadratic equation if + + + align:start position:0% +we could use the quadratic equation if +we simplify it we calculate X as 4.87 * + + align:start position:0% +we simplify it we calculate X as 4.87 * + + + align:start position:0% +we simplify it we calculate X as 4.87 * +10-4 and remember again that the + + align:start position:0% +10-4 and remember again that the + + + align:start position:0% +10-4 and remember again that the +approximation is you get rid of the plus + + align:start position:0% +approximation is you get rid of the plus + + + align:start position:0% +approximation is you get rid of the plus +X and Theus X + + align:start position:0% +X and Theus X + + + align:start position:0% +X and Theus X +here and then you have to check it with + + align:start position:0% +here and then you have to check it with + + + align:start position:0% +here and then you have to check it with +the 5% rule if you did that if you use + + align:start position:0% +the 5% rule if you did that if you use + + + align:start position:0% +the 5% rule if you did that if you use +the quadratic you don't have to check + + align:start position:0% +the quadratic you don't have to check + + + align:start position:0% +the quadratic you don't have to check +but if you use the 5% rule then you're + + align:start position:0% +but if you use the 5% rule then you're + + + align:start position:0% +but if you use the 5% rule then you're +asking is this number 4.87 * 10us 4 um + + align:start position:0% +asking is this number 4.87 * 10us 4 um + + + align:start position:0% +asking is this number 4.87 * 10us 4 um +within 5% of the smaller value which is + + align:start position:0% +within 5% of the smaller value which is + + + align:start position:0% +within 5% of the smaller value which is +04 and it is here it's + + align:start position:0% +04 and it is here it's + + + align:start position:0% +04 and it is here it's +0.12% so the assumption is okay that's + + align:start position:0% +0.12% so the assumption is okay that's + + + align:start position:0% +0.12% so the assumption is okay that's +less than 5% X is small and then we can + + align:start position:0% +less than 5% X is small and then we can + + + align:start position:0% +less than 5% X is small and then we can +solve um for for the pH so pH is minus + + align:start position:0% +solve um for for the pH so pH is minus + + + align:start position:0% +solve um for for the pH so pH is minus +log of the hydronium ion concentration + + align:start position:0% +log of the hydronium ion concentration + + + align:start position:0% +log of the hydronium ion concentration +which here is + + align:start position:0% +which here is + + + align:start position:0% +which here is +3.31 this only is two significant + + align:start position:0% +3.31 this only is two significant + + + align:start position:0% +3.31 this only is two significant +figures after the decimal because if you + + align:start position:0% +figures after the decimal because if you + + + align:start position:0% +figures after the decimal because if you +remember back on the other page the + + align:start position:0% +remember back on the other page the + + + align:start position:0% +remember back on the other page the +volume only had two so actually all + + align:start position:0% +volume only had two so actually all + + + align:start position:0% +volume only had two so actually all +these numbers here really just have two + + align:start position:0% +these numbers here really just have two + + + align:start position:0% +these numbers here really just have two +significant figures um we carried an + + align:start position:0% +significant figures um we carried an + + + align:start position:0% +significant figures um we carried an +extra um but it really just had two all + + align:start position:0% +extra um but it really just had two all + + + align:start position:0% +extra um but it really just had two all +right so our buffer was pretty good so + + align:start position:0% +right so our buffer was pretty good so + + + align:start position:0% +right so our buffer was pretty good so +we added 0.1 moles of a very strong acid + + align:start position:0% +we added 0.1 moles of a very strong acid + + + align:start position:0% +we added 0.1 moles of a very strong acid +and we only changed the pH we only + + align:start position:0% +and we only changed the pH we only + + + align:start position:0% +and we only changed the pH we only +lowered it from 3.45 to + + align:start position:0% +lowered it from 3.45 to + + + align:start position:0% +lowered it from 3.45 to +3.31 so that was a pretty good buffer + + align:start position:0% +3.31 so that was a pretty good buffer + + + align:start position:0% +3.31 so that was a pretty good buffer +that we had that we had uh designed + + align:start position:0% +that we had that we had uh designed + + + align:start position:0% +that we had that we had uh designed +there all right so that is how you do um + + align:start position:0% +there all right so that is how you do um + + + align:start position:0% +there all right so that is how you do um +a buffer problem and there are other + + align:start position:0% +a buffer problem and there are other + + + align:start position:0% +a buffer problem and there are other +kindes of things that you can be asked + + align:start position:0% +kindes of things that you can be asked + + + align:start position:0% +kindes of things that you can be asked +about with buffers um in particular you + + align:start position:0% +about with buffers um in particular you + + + align:start position:0% +about with buffers um in particular you +can also often be asked uh to design a + + align:start position:0% +can also often be asked uh to design a + + + align:start position:0% +can also often be asked uh to design a +buffer and when you design a buffer you + + align:start position:0% +buffer and when you design a buffer you + + + align:start position:0% +buffer and when you design a buffer you +must consider the following things the + + align:start position:0% +must consider the following things the + + + align:start position:0% +must consider the following things the +ratio of your conjugate acidbase pair + + align:start position:0% +ratio of your conjugate acidbase pair + + + align:start position:0% +ratio of your conjugate acidbase pair +and that they should also be weak + + align:start position:0% +and that they should also be weak + + + align:start position:0% +and that they should also be weak +conjugate acid based pairs the + + align:start position:0% +conjugate acid based pairs the + + + align:start position:0% +conjugate acid based pairs the +pka and the pH okay so here comes a + + align:start position:0% + + + + align:start position:0% + +derivation so here is our expression + + align:start position:0% +derivation so here is our expression + + + align:start position:0% +derivation so here is our expression +that should be familiar to you at this + + align:start position:0% +that should be familiar to you at this + + + align:start position:0% +that should be familiar to you at this +point for a weak acid ha in water going + + align:start position:0% +point for a weak acid ha in water going + + + align:start position:0% +point for a weak acid ha in water going +to hydronium ions and our conjugate base + + align:start position:0% +to hydronium ions and our conjugate base + + + align:start position:0% +to hydronium ions and our conjugate base +A minus it should also be familiar to + + align:start position:0% +A minus it should also be familiar to + + + align:start position:0% +A minus it should also be familiar to +you that you can write the um + + align:start position:0% +you that you can write the um + + + align:start position:0% +you that you can write the um +equilibrium expression for this acid in + + align:start position:0% +equilibrium expression for this acid in + + + align:start position:0% +equilibrium expression for this acid in +water as hydronium ion concentration + + align:start position:0% +water as hydronium ion concentration + + + align:start position:0% +water as hydronium ion concentration +times the concentration of the conjugate + + align:start position:0% +times the concentration of the conjugate + + + align:start position:0% +times the concentration of the conjugate +base over the concentration of the + + align:start position:0% +base over the concentration of the + + + align:start position:0% +base over the concentration of the +conjugate acid water which is our + + align:start position:0% +conjugate acid water which is our + + + align:start position:0% +conjugate acid water which is our +solvent doesn't appear in the + + align:start position:0% +solvent doesn't appear in the + + + align:start position:0% +solvent doesn't appear in the +expression we can rearrange this + + align:start position:0% +expression we can rearrange this + + + align:start position:0% +expression we can rearrange this +expression now and solve for hydronium + + align:start position:0% +expression now and solve for hydronium + + + align:start position:0% +expression now and solve for hydronium +ion + + align:start position:0% +ion + + + align:start position:0% +ion +concentrations we can take the log of + + align:start position:0% +concentrations we can take the log of + + + align:start position:0% +concentrations we can take the log of +both sides and get this log of hydronium + + align:start position:0% +both sides and get this log of hydronium + + + align:start position:0% +both sides and get this log of hydronium +concentration log of Ka plus log of ha + + align:start position:0% +concentration log of Ka plus log of ha + + + align:start position:0% +concentration log of Ka plus log of ha +over a minus multiply by negative to get + + align:start position:0% +over a minus multiply by negative to get + + + align:start position:0% +over a minus multiply by negative to get +this and so we have minus minus minus + + align:start position:0% +this and so we have minus minus minus + + + align:start position:0% +this and so we have minus minus minus +and minus the log of the hydronium ion + + align:start position:0% +and minus the log of the hydronium ion + + + align:start position:0% +and minus the log of the hydronium ion +concentration is what PH minus log of Ka + + align:start position:0% +concentration is what PH minus log of Ka + + + align:start position:0% +concentration is what PH minus log of Ka +is PKA and this is the same as that so + + align:start position:0% +is PKA and this is the same as that so + + + align:start position:0% +is PKA and this is the same as that so +that gives us this expression that pH + + align:start position:0% +that gives us this expression that pH + + + align:start position:0% +that gives us this expression that pH +equals PKA minus + + align:start position:0% +equals PKA minus + + + align:start position:0% +equals PKA minus +um the log of ha over a minus now it's + + align:start position:0% +um the log of ha over a minus now it's + + + align:start position:0% +um the log of ha over a minus now it's +important to point out that these are + + align:start position:0% +important to point out that these are + + + align:start position:0% +important to point out that these are +equilibrium concentrations of ha and a + + align:start position:0% +equilibrium concentrations of ha and a + + + align:start position:0% +equilibrium concentrations of ha and a +minus because we derived this expression + + align:start position:0% +minus because we derived this expression + + + align:start position:0% +minus because we derived this expression +from Ka and that's an equilibrium + + align:start position:0% +from Ka and that's an equilibrium + + + align:start position:0% +from Ka and that's an equilibrium +constant so these are equilibrium + + align:start position:0% +constant so these are equilibrium + + + align:start position:0% +constant so these are equilibrium +expressions and that makes this + + align:start position:0% +expressions and that makes this + + + align:start position:0% +expressions and that makes this +particular expression slightly less + + align:start position:0% +particular expression slightly less + + + align:start position:0% +particular expression slightly less +useful because we often don't want to + + align:start position:0% +useful because we often don't want to + + + align:start position:0% +useful because we often don't want to +have to calculate the equilibrium + + align:start position:0% +have to calculate the equilibrium + + + align:start position:0% +have to calculate the equilibrium +concentration we know how much we added + + align:start position:0% +concentration we know how much we added + + + align:start position:0% +concentration we know how much we added +and so we often want to use initial + + align:start position:0% +and so we often want to use initial + + + align:start position:0% +and so we often want to use initial +concentrations but we can consider + + align:start position:0% +concentrations but we can consider + + + align:start position:0% +concentrations but we can consider +whether the initial concentrations are + + align:start position:0% +whether the initial concentrations are + + + align:start position:0% +whether the initial concentrations are +actually pretty similar to the + + align:start position:0% +actually pretty similar to the + + + align:start position:0% +actually pretty similar to the +equilibrium concentrations I.E that X is + + align:start position:0% +equilibrium concentrations I.E that X is + + + align:start position:0% +equilibrium concentrations I.E that X is +small less than 5% so we know that a + + align:start position:0% +small less than 5% so we know that a + + + align:start position:0% +small less than 5% so we know that a +weak acid typically only loses a + + align:start position:0% +weak acid typically only loses a + + + align:start position:0% +weak acid typically only loses a +fraction of its protons hence the + + align:start position:0% +fraction of its protons hence the + + + align:start position:0% +fraction of its protons hence the +definition of weak acid weak acid in + + align:start position:0% +definition of weak acid weak acid in + + + align:start position:0% +definition of weak acid weak acid in +water doesn't ionize that much and a + + align:start position:0% +water doesn't ionize that much and a + + + align:start position:0% +water doesn't ionize that much and a +weak base typically only accepts a + + align:start position:0% +weak base typically only accepts a + + + align:start position:0% +weak base typically only accepts a +fraction of the protons that it could if + + align:start position:0% +fraction of the protons that it could if + + + align:start position:0% +fraction of the protons that it could if +it's a weak base so the initial + + align:start position:0% +it's a weak base so the initial + + + align:start position:0% +it's a weak base so the initial +concentration is often approximately + + align:start position:0% +concentration is often approximately + + + align:start position:0% +concentration is often approximately +equal to the equilibrium concentration + + align:start position:0% +equal to the equilibrium concentration + + + align:start position:0% +equal to the equilibrium concentration +and that's what we've been finding in a + + align:start position:0% +and that's what we've been finding in a + + + align:start position:0% +and that's what we've been finding in a +lot of these problems we find that the + + align:start position:0% +lot of these problems we find that the + + + align:start position:0% +lot of these problems we find that the +5% rule works pretty well it's usually + + align:start position:0% +5% rule works pretty well it's usually + + + align:start position:0% +5% rule works pretty well it's usually +less than 5% X is usually less than 5% + + align:start position:0% +less than 5% X is usually less than 5% + + + align:start position:0% +less than 5% X is usually less than 5% +of the initial concentration we had of + + align:start position:0% +of the initial concentration we had of + + + align:start position:0% +of the initial concentration we had of +ha or a minus and so therefore we can + + align:start position:0% +ha or a minus and so therefore we can + + + align:start position:0% +ha or a minus and so therefore we can +say that the pH is in fact approximately + + align:start position:0% +say that the pH is in fact approximately + + + align:start position:0% +say that the pH is in fact approximately +equal to the pka minus the log of the + + align:start position:0% +equal to the pka minus the log of the + + + align:start position:0% +equal to the pka minus the log of the +initial concentration of your ha over + + align:start position:0% +initial concentration of your ha over + + + align:start position:0% +initial concentration of your ha over +your initial concentration of a minus + + align:start position:0% +your initial concentration of a minus + + + align:start position:0% +your initial concentration of a minus +and this expression is known as the + + align:start position:0% +and this expression is known as the + + + align:start position:0% +and this expression is known as the +Henderson hosbach um equation and so + + align:start position:0% +Henderson hosbach um equation and so + + + align:start position:0% +Henderson hosbach um equation and so +this equation is only valid + + align:start position:0% +this equation is only valid + + + align:start position:0% +this equation is only valid +when your hydronium ion concentration is + + align:start position:0% +when your hydronium ion concentration is + + + align:start position:0% +when your hydronium ion concentration is +small compared to ha and a minus I.E + + align:start position:0% +small compared to ha and a minus I.E + + + align:start position:0% +small compared to ha and a minus I.E +less than 5% so this 5% rule + + align:start position:0% +less than 5% so this 5% rule + + + align:start position:0% +less than 5% so this 5% rule +must apply to use the Henderson hosbach + + align:start position:0% +must apply to use the Henderson hosbach + + + align:start position:0% +must apply to use the Henderson hosbach +equation the Henderson hosbach equation + + align:start position:0% +equation the Henderson hosbach equation + + + align:start position:0% +equation the Henderson hosbach equation +is a great equation to use for buffer + + align:start position:0% +is a great equation to use for buffer + + + align:start position:0% +is a great equation to use for buffer +problems and so we've showed you a + + align:start position:0% +problems and so we've showed you a + + + align:start position:0% +problems and so we've showed you a +couple different ways of doing buffer + + align:start position:0% +couple different ways of doing buffer + + + align:start position:0% +couple different ways of doing buffer +problems this is the final way I'm going + + align:start position:0% +problems this is the final way I'm going + + + align:start position:0% +problems this is the final way I'm going +to show you using the Henderson hoselock + + align:start position:0% +to show you using the Henderson hoselock + + + align:start position:0% +to show you using the Henderson hoselock +equation but you can only use it if x is + + align:start position:0% +equation but you can only use it if x is + + + align:start position:0% +equation but you can only use it if x is +small but most of the time x is going to + + align:start position:0% +small but most of the time x is going to + + + align:start position:0% +small but most of the time x is going to +be small because buffers are only + + align:start position:0% +be small because buffers are only + + + align:start position:0% +be small because buffers are only +buffers when you have a weak acid with a + + align:start position:0% +buffers when you have a weak acid with a + + + align:start position:0% +buffers when you have a weak acid with a +conjugate weak base + + align:start position:0% +conjugate weak base + + + align:start position:0% +conjugate weak base +and when you're talking about weak acids + + align:start position:0% +and when you're talking about weak acids + + + align:start position:0% +and when you're talking about weak acids +and bases X is small they don't ionize + + align:start position:0% +and bases X is small they don't ionize + + + align:start position:0% +and bases X is small they don't ionize +that much and importantly and I'll + + align:start position:0% +that much and importantly and I'll + + + align:start position:0% +that much and importantly and I'll +emphasize this this equation only works + + align:start position:0% +emphasize this this equation only works + + + align:start position:0% +emphasize this this equation only works +for buffers don't apply it for a just a + + align:start position:0% +for buffers don't apply it for a just a + + + align:start position:0% +for buffers don't apply it for a just a +regular weak acid in water or a weak + + align:start position:0% +regular weak acid in water or a weak + + + align:start position:0% +regular weak acid in water or a weak +base in water a strong acid in water a + + align:start position:0% +base in water a strong acid in water a + + + align:start position:0% +base in water a strong acid in water a +strong base in water it only applies for + + align:start position:0% +strong base in water it only applies for + + + align:start position:0% +strong base in water it only applies for +buffers buffers + + align:start position:0% +buffers buffers + + + align:start position:0% +buffers buffers +buffers now I know that MIT students + + align:start position:0% +buffers now I know that MIT students + + + align:start position:0% +buffers now I know that MIT students +love equations and they love doing math + + align:start position:0% +love equations and they love doing math + + + align:start position:0% +love equations and they love doing math +and so they try to apply this equation + + align:start position:0% +and so they try to apply this equation + + + align:start position:0% +and so they try to apply this equation +to every type of acidbase problem don't + + align:start position:0% +to every type of acidbase problem don't + + + align:start position:0% +to every type of acidbase problem don't +do it buffers + + align:start position:0% + + + + align:start position:0% + +buffers you'll remember that now + + align:start position:0% +buffers you'll remember that now + + + align:start position:0% +buffers you'll remember that now +right because I'll I'll make noises + + align:start position:0% +right because I'll I'll make noises + + + align:start position:0% +right because I'll I'll make noises +again if you don't you'll remember that + + align:start position:0% +again if you don't you'll remember that + + + align:start position:0% +again if you don't you'll remember that +now + + align:start position:0% +now + + + align:start position:0% +now +right all right so let's use the + + align:start position:0% +right all right so let's use the + + + align:start position:0% +right all right so let's use the +Henderson hasselbach uh to design a + + align:start position:0% +Henderson hasselbach uh to design a + + + align:start position:0% +Henderson hasselbach uh to design a +buffer then so say we want to design a + + align:start position:0% +buffer then so say we want to design a + + + align:start position:0% +buffer then so say we want to design a +buffer at pH 6 uh 4.6 say you're + + align:start position:0% +buffer at pH 6 uh 4.6 say you're + + + align:start position:0% +buffer at pH 6 uh 4.6 say you're +interviewing for a europ position and uh + + align:start position:0% +interviewing for a europ position and uh + + + align:start position:0% +interviewing for a europ position and uh +the europ uh supervisor the the PI says + + align:start position:0% +the europ uh supervisor the the PI says + + + align:start position:0% +the europ uh supervisor the the PI says +uh tell me how you would design a buffer + + align:start position:0% +uh tell me how you would design a buffer + + + align:start position:0% +uh tell me how you would design a buffer +um pH 4.6 and you might uh go to the + + align:start position:0% +um pH 4.6 and you might uh go to the + + + align:start position:0% +um pH 4.6 and you might uh go to the +shelf and see what was available and + + align:start position:0% +shelf and see what was available and + + + align:start position:0% +shelf and see what was available and +then look up what uh the KA and PKA are + + align:start position:0% +then look up what uh the KA and PKA are + + + align:start position:0% +then look up what uh the KA and PKA are +because a buffer solution is most most + + align:start position:0% +because a buffer solution is most most + + + align:start position:0% +because a buffer solution is most most +effective in the range of the pka plus + + align:start position:0% +effective in the range of the pka plus + + + align:start position:0% +effective in the range of the pka plus +or minus one in fact the closer the pH + + align:start position:0% +or minus one in fact the closer the pH + + + align:start position:0% +or minus one in fact the closer the pH +that you want is to the pka the better + + align:start position:0% +that you want is to the pka the better + + + align:start position:0% +that you want is to the pka the better +the buffer it's going to be so we can + + align:start position:0% +the buffer it's going to be so we can + + + align:start position:0% +the buffer it's going to be so we can +look and see what's in the range there's + + align:start position:0% +look and see what's in the range there's + + + align:start position:0% +look and see what's in the range there's +several that are close to 4.6 that we + + align:start position:0% +several that are close to 4.6 that we + + + align:start position:0% +several that are close to 4.6 that we +can choose from and probably would end + + align:start position:0% +can choose from and probably would end + + + align:start position:0% +can choose from and probably would end +up choosing acetic acid because that + + align:start position:0% +up choosing acetic acid because that + + + align:start position:0% +up choosing acetic acid because that +would be on the Shelf whereas some of + + align:start position:0% +would be on the Shelf whereas some of + + + align:start position:0% +would be on the Shelf whereas some of +the others of these would not be there + + align:start position:0% +the others of these would not be there + + + align:start position:0% +the others of these would not be there +all right so acetate is going to work + + align:start position:0% +all right so acetate is going to work + + + align:start position:0% +all right so acetate is going to work +it's a pretty common buffer um so we can + + align:start position:0% +it's a pretty common buffer um so we can + + + align:start position:0% +it's a pretty common buffer um so we can +use acetic acid with a suitable pka of + + align:start position:0% +use acetic acid with a suitable pka of + + + align:start position:0% +use acetic acid with a suitable pka of +4.75 then we can use the Henderson + + align:start position:0% +4.75 then we can use the Henderson + + + align:start position:0% +4.75 then we can use the Henderson +hoselock equation because we're + + align:start position:0% +hoselock equation because we're + + + align:start position:0% +hoselock equation because we're +designing a buffer so we can use that + + align:start position:0% +designing a buffer so we can use that + + + align:start position:0% +designing a buffer so we can use that +equation and figure out what the ratio + + align:start position:0% +equation and figure out what the ratio + + + align:start position:0% +equation and figure out what the ratio +of acetic acid to its conjugate base + + align:start position:0% +of acetic acid to its conjugate base + + + align:start position:0% +of acetic acid to its conjugate base +should + + align:start position:0% +should + + + align:start position:0% +should +be so we can rearrange this expression + + align:start position:0% +be so we can rearrange this expression + + + align:start position:0% +be so we can rearrange this expression +we know the pka and we know the pH that + + align:start position:0% +we know the pka and we know the pH that + + + align:start position:0% +we know the pka and we know the pH that +we want and so we can subtract those and + + align:start position:0% +we want and so we can subtract those and + + + align:start position:0% +we want and so we can subtract those and +we get that the log of the ratio should + + align:start position:0% +we get that the log of the ratio should + + + align:start position:0% +we get that the log of the ratio should +be + + align:start position:0% +be + + + align:start position:0% +be +.15 and then inverse log will tell us + + align:start position:0% +.15 and then inverse log will tell us + + + align:start position:0% +.15 and then inverse log will tell us +that the ratio then of the acid to the + + align:start position:0% +that the ratio then of the acid to the + + + align:start position:0% +that the ratio then of the acid to the +conjugate base should be + + align:start position:0% +conjugate base should be + + + align:start position:0% +conjugate base should be +1.4 so you should use things with that + + align:start position:0% +1.4 so you should use things with that + + + align:start position:0% +1.4 so you should use things with that +ratio so for example you could use 1.4 + + align:start position:0% +ratio so for example you could use 1.4 + + + align:start position:0% +ratio so for example you could use 1.4 +molar of the acid to one molar of the + + align:start position:0% +molar of the acid to one molar of the + + + align:start position:0% +molar of the acid to one molar of the +conjugate base and + + align:start position:0% +conjugate base and + + + align:start position:0% +conjugate base and +the the uh the total amounts are often + + align:start position:0% +the the uh the total amounts are often + + + align:start position:0% +the the uh the total amounts are often +less important than the ratio the ratio + + align:start position:0% +less important than the ratio the ratio + + + align:start position:0% +less important than the ratio the ratio +is very important but if you go too low + + align:start position:0% +is very important but if you go too low + + + align:start position:0% +is very important but if you go too low +in + + align:start position:0% +in + + + align:start position:0% +in +concentrations then that'll affect + + align:start position:0% +concentrations then that'll affect + + + align:start position:0% +concentrations then that'll affect +what's known as the buffering capacity + + align:start position:0% +what's known as the buffering capacity + + + align:start position:0% +what's known as the buffering capacity +which is the ability of the buffer to + + align:start position:0% +which is the ability of the buffer to + + + align:start position:0% +which is the ability of the buffer to +resist changes so if it's too dilute and + + align:start position:0% +resist changes so if it's too dilute and + + + align:start position:0% +resist changes so if it's too dilute and +a lot of strong acid or a lot of strong + + align:start position:0% +a lot of strong acid or a lot of strong + + + align:start position:0% +a lot of strong acid or a lot of strong +bases added then it won't be a good + + align:start position:0% +bases added then it won't be a good + + + align:start position:0% +bases added then it won't be a good +buffer anymore so the ratio is very + + align:start position:0% +buffer anymore so the ratio is very + + + align:start position:0% +buffer anymore so the ratio is very +important the amounts are important such + + align:start position:0% +important the amounts are important such + + + align:start position:0% +important the amounts are important such +that you have some resistance to change + + align:start position:0% +that you have some resistance to change + + + align:start position:0% +that you have some resistance to change +so the higher + + align:start position:0% +so the higher + + + align:start position:0% +so the higher +concentrations the more resistant to + + align:start position:0% + + + + align:start position:0% + +change and if you Lo also if you use too + + align:start position:0% +change and if you Lo also if you use too + + + align:start position:0% +change and if you Lo also if you use too +low a concentration the Henderson + + align:start position:0% +low a concentration the Henderson + + + align:start position:0% +low a concentration the Henderson +hoselock equation is no longer valid so + + align:start position:0% +hoselock equation is no longer valid so + + + align:start position:0% +hoselock equation is no longer valid so +you can be asked to calculate sort of + + align:start position:0% +you can be asked to calculate sort of + + + align:start position:0% +you can be asked to calculate sort of +what the minimum concentration is that + + align:start position:0% +what the minimum concentration is that + + + align:start position:0% +what the minimum concentration is that +you would need to use and so for H 6 uh + + align:start position:0% +you would need to use and so for H 6 uh + + + align:start position:0% +you would need to use and so for H 6 uh +4.60 you can back calculate what the + + align:start position:0% +4.60 you can back calculate what the + + + align:start position:0% +4.60 you can back calculate what the +hydronium ion concentration is and it's + + align:start position:0% +hydronium ion concentration is and it's + + + align:start position:0% +hydronium ion concentration is and it's +2.5 * 10us 5 so for our 5% assumption to + + align:start position:0% +2.5 * 10us 5 so for our 5% assumption to + + + align:start position:0% +2.5 * 10us 5 so for our 5% assumption to +hold or to be valid that this number the + + align:start position:0% +hold or to be valid that this number the + + + align:start position:0% +hold or to be valid that this number the +hydronium ion concentration is less than + + align:start position:0% +hydronium ion concentration is less than + + + align:start position:0% +hydronium ion concentration is less than +5% of either one of these the + + align:start position:0% +5% of either one of these the + + + align:start position:0% +5% of either one of these the +concentrations here would have to be + + align:start position:0% +concentrations here would have to be + + + align:start position:0% +concentrations here would have to be +greater than 5 * 10us 4 so if if we use + + align:start position:0% +greater than 5 * 10us 4 so if if we use + + + align:start position:0% +greater than 5 * 10us 4 so if if we use +one Moler or something that's way above + + align:start position:0% +one Moler or something that's way above + + + align:start position:0% +one Moler or something that's way above +this but that would be the minimum if + + align:start position:0% +this but that would be the minimum if + + + align:start position:0% +this but that would be the minimum if +it's less than that that 5% doesn't + + align:start position:0% +it's less than that that 5% doesn't + + + align:start position:0% +it's less than that that 5% doesn't +really hold and you would not have a + + align:start position:0% +really hold and you would not have a + + + align:start position:0% +really hold and you would not have a +very good buffer in that case it + + align:start position:0% +very good buffer in that case it + + + align:start position:0% +very good buffer in that case it +wouldn't be very resistance to change X + + align:start position:0% +wouldn't be very resistance to change X + + + align:start position:0% +wouldn't be very resistance to change X +would be big compared to those numbers + + align:start position:0% +would be big compared to those numbers + + + align:start position:0% +would be big compared to those numbers +so that's how you go about designing a + + align:start position:0% +so that's how you go about designing a + + + align:start position:0% +so that's how you go about designing a +buffer and in that there were two things + + align:start position:0% +buffer and in that there were two things + + + align:start position:0% +buffer and in that there were two things +that are really common mistakes when I'm + + align:start position:0% +that are really common mistakes when I'm + + + align:start position:0% +that are really common mistakes when I'm +reviewing a paper for publication two of + + align:start position:0% +reviewing a paper for publication two of + + + align:start position:0% +reviewing a paper for publication two of +the things that I see the most often is + + align:start position:0% +the things that I see the most often is + + + align:start position:0% +the things that I see the most often is +that people one do not use the right + + align:start position:0% +that people one do not use the right + + + align:start position:0% +that people one do not use the right +buffer for their experiment they say oh + + align:start position:0% +buffer for their experiment they say oh + + + align:start position:0% +buffer for their experiment they say oh +I'm at P you know ph8 and they'll use a + + align:start position:0% +I'm at P you know ph8 and they'll use a + + + align:start position:0% +I'm at P you know ph8 and they'll use a +buffer that is in fact not a good buffer + + align:start position:0% +buffer that is in fact not a good buffer + + + align:start position:0% +buffer that is in fact not a good buffer +at ph8 so who knows what their data is + + align:start position:0% +at ph8 so who knows what their data is + + + align:start position:0% +at ph8 so who knows what their data is +telling us and the other thing that + + align:start position:0% +telling us and the other thing that + + + align:start position:0% +telling us and the other thing that +people will do is that they'll say oh + + align:start position:0% +people will do is that they'll say oh + + + align:start position:0% +people will do is that they'll say oh +yes it was buffered and the pka might be + + align:start position:0% +yes it was buffered and the pka might be + + + align:start position:0% +yes it was buffered and the pka might be +right but the concentration of the + + align:start position:0% +right but the concentration of the + + + align:start position:0% +right but the concentration of the +buffer is so low that you don't really + + align:start position:0% +buffer is so low that you don't really + + + align:start position:0% +buffer is so low that you don't really +imagine the buffer is doing anything so + + align:start position:0% +imagine the buffer is doing anything so + + + align:start position:0% +imagine the buffer is doing anything so +now you know how to avoid both of those + + align:start position:0% +now you know how to avoid both of those + + + align:start position:0% +now you know how to avoid both of those +pitfalls \ No newline at end of file diff --git a/crMyNv2fdkc.txt b/crMyNv2fdkc.txt new file mode 100644 index 0000000000000000000000000000000000000000..400fe7d64f82726e8ffbb4b453f06f1cd23160bf --- /dev/null +++ b/crMyNv2fdkc.txt @@ -0,0 +1,947 @@ +align:start position:0% + +the probabilistic method in + + align:start position:0% +the probabilistic method in + + + align:start position:0% +the probabilistic method in +combinatorics is a powerful method that + + align:start position:0% +combinatorics is a powerful method that + + + align:start position:0% +combinatorics is a powerful method that +can be used to demonstrate the existence + + align:start position:0% +can be used to demonstrate the existence + + + align:start position:0% +can be used to demonstrate the existence +of some object by introducing + + align:start position:0% +of some object by introducing + + + align:start position:0% +of some object by introducing +Randomness in this video we'll look at a + + align:start position:0% +Randomness in this video we'll look at a + + + align:start position:0% +Randomness in this video we'll look at a +basic example illustrating an + + align:start position:0% +basic example illustrating an + + + align:start position:0% +basic example illustrating an +application of the probabilistic method + + align:start position:0% +application of the probabilistic method + + + align:start position:0% +application of the probabilistic method +we'll show this theorem over here which + + align:start position:0% +we'll show this theorem over here which + + + align:start position:0% +we'll show this theorem over here which +says that if G is a graph with M edges + + align:start position:0% +says that if G is a graph with M edges + + + align:start position:0% +says that if G is a graph with M edges +then G has a bipartite subgraph with at + + align:start position:0% +then G has a bipartite subgraph with at + + + align:start position:0% +then G has a bipartite subgraph with at +least M over two edges so let me remind + + align:start position:0% +least M over two edges so let me remind + + + align:start position:0% +least M over two edges so let me remind +you the definition of a bipar graph is + + align:start position:0% +you the definition of a bipar graph is + + + align:start position:0% +you the definition of a bipar graph is +one where I can partition the vertices + + align:start position:0% +one where I can partition the vertices + + + align:start position:0% +one where I can partition the vertices +into two halves or two sets of vertices + + align:start position:0% +into two halves or two sets of vertices + + + align:start position:0% +into two halves or two sets of vertices +and all the + + align:start position:0% +and all the + + + align:start position:0% +and all the +edges go from one side to the other so + + align:start position:0% +edges go from one side to the other so + + + align:start position:0% +edges go from one side to the other so +that's an example of a bipartite graph + + align:start position:0% + + + + align:start position:0% + +and what this theorem is saying is that + + align:start position:0% +and what this theorem is saying is that + + + align:start position:0% +and what this theorem is saying is that +if we start with any graph G + + align:start position:0% +if we start with any graph G + + + align:start position:0% +if we start with any graph G +with some number of edges in this case + + align:start position:0% +with some number of edges in this case + + + align:start position:0% +with some number of edges in this case +five + + align:start position:0% +five + + + align:start position:0% +five +edges I can find a pretty large subgraph + + align:start position:0% +edges I can find a pretty large subgraph + + + align:start position:0% +edges I can find a pretty large subgraph +by keeping at least half of the edges of + + align:start position:0% +by keeping at least half of the edges of + + + align:start position:0% +by keeping at least half of the edges of +G for example we can do this keeping + + align:start position:0% +G for example we can do this keeping + + + align:start position:0% +G for example we can do this keeping +four of the five edges to get this + + align:start position:0% +four of the five edges to get this + + + align:start position:0% +four of the five edges to get this +subgraph G Prime and this graph G Prime + + align:start position:0% +subgraph G Prime and this graph G Prime + + + align:start position:0% +subgraph G Prime and this graph G Prime +is now bipart + + align:start position:0% +is now bipart + + + align:start position:0% +is now bipart +because I + + align:start position:0% +because I + + + align:start position:0% +because I +can put these two vertices on one + + align:start position:0% +can put these two vertices on one + + + align:start position:0% +can put these two vertices on one +side and these two vertices on the other + + align:start position:0% +side and these two vertices on the other + + + align:start position:0% +side and these two vertices on the other +side so that you see all the edges go + + align:start position:0% +side so that you see all the edges go + + + align:start position:0% +side so that you see all the edges go +from the red or the pink vertices to the + + align:start position:0% +from the red or the pink vertices to the + + + align:start position:0% +from the red or the pink vertices to the +green vertices and none between the pink + + align:start position:0% +green vertices and none between the pink + + + align:start position:0% +green vertices and none between the pink +and none between the + + align:start position:0% +and none between the + + + align:start position:0% +and none between the +greens so this is an example of um + + align:start position:0% +greens so this is an example of um + + + align:start position:0% +greens so this is an example of um +finding a large bipar subgraph in a + + align:start position:0% +finding a large bipar subgraph in a + + + align:start position:0% +finding a large bipar subgraph in a +graph G now let me prove this theorem + + align:start position:0% +graph G now let me prove this theorem + + + align:start position:0% +graph G now let me prove this theorem +illustrating the probabilistic + + align:start position:0% + + + + align:start position:0% + +method so we're given this graph G and + + align:start position:0% +method so we're given this graph G and + + + align:start position:0% +method so we're given this graph G and +what we'll do is + + align:start position:0% +what we'll do is + + + align:start position:0% +what we'll do is +assign + + align:start position:0% +assign + + + align:start position:0% +assign +a + + align:start position:0% +a + + + align:start position:0% +a +color which will be either black or + + align:start position:0% + + + + align:start position:0% + +white + + align:start position:0% +white + + + align:start position:0% +white +uniformly and independently at random + + align:start position:0% + + + + align:start position:0% + +to each + + align:start position:0% + + + + align:start position:0% + +vertex of the graph + + align:start position:0% +vertex of the graph + + + align:start position:0% +vertex of the graph +G so imagine flipping a coin for each + + align:start position:0% +G so imagine flipping a coin for each + + + align:start position:0% +G so imagine flipping a coin for each +vertex and coloring each vertex black or + + align:start position:0% +vertex and coloring each vertex black or + + + align:start position:0% +vertex and coloring each vertex black or +white after doing this we can put all + + align:start position:0% +white after doing this we can put all + + + align:start position:0% +white after doing this we can put all +the white vertices of G on one side and + + align:start position:0% +the white vertices of G on one side and + + + align:start position:0% +the white vertices of G on one side and +all the black vertices of G on the other + + align:start position:0% +all the black vertices of G on the other + + + align:start position:0% +all the black vertices of G on the other +side okay so now G has some number of + + align:start position:0% +side okay so now G has some number of + + + align:start position:0% +side okay so now G has some number of +vertices and there will be some edges + + align:start position:0% +vertices and there will be some edges + + + align:start position:0% +vertices and there will be some edges +going across from white to black some + + align:start position:0% +going across from white to black some + + + align:start position:0% +going across from white to black some +edges within white and some edges within + + align:start position:0% +edges within white and some edges within + + + align:start position:0% +edges within white and some edges within +black there could be a lot more edges + + align:start position:0% +black there could be a lot more edges + + + align:start position:0% +black there could be a lot more edges +but that's an example of what this graph + + align:start position:0% +but that's an example of what this graph + + + align:start position:0% +but that's an example of what this graph +might look + + align:start position:0% +might look + + + align:start position:0% +might look +like and now let me take G Prime to be + + align:start position:0% +like and now let me take G Prime to be + + + align:start position:0% +like and now let me take G Prime to be +the subgraph + + align:start position:0% + + + + align:start position:0% + +consisting of + + align:start position:0% +consisting of + + + align:start position:0% +consisting of +edges with white on one end and black on + + align:start position:0% +edges with white on one end and black on + + + align:start position:0% +edges with white on one end and black on +the other end so two different colors on + + align:start position:0% +the other end so two different colors on + + + align:start position:0% +the other end so two different colors on +the two edges two end points of this + + align:start position:0% +the two edges two end points of this + + + align:start position:0% +the two edges two end points of this +Edge this is a subgraph it's a subset of + + align:start position:0% +Edge this is a subgraph it's a subset of + + + align:start position:0% +Edge this is a subgraph it's a subset of +the edges of + + align:start position:0% +the edges of + + + align:start position:0% +the edges of +G and note + + align:start position:0% +G and note + + + align:start position:0% +G and note +that + + align:start position:0% +that + + + align:start position:0% +that +every + + align:start position:0% +every + + + align:start position:0% +every +edge of G + + align:start position:0% +edge of G + + + align:start position:0% +edge of G +has + + align:start position:0% +has + + + align:start position:0% +has +probability 1 half of + + align:start position:0% +probability 1 half of + + + align:start position:0% +probability 1 half of +Being in G Prime because for this Edge + + align:start position:0% +Being in G Prime because for this Edge + + + align:start position:0% +Being in G Prime because for this Edge +there are four different + + align:start position:0% +there are four different + + + align:start position:0% +there are four different +possibilities for what the endpoint + + align:start position:0% +possibilities for what the endpoint + + + align:start position:0% +possibilities for what the endpoint +colors might look like and these four + + align:start position:0% +colors might look like and these four + + + align:start position:0% +colors might look like and these four +possibilities are equally likely and + + align:start position:0% +possibilities are equally likely and + + + align:start position:0% +possibilities are equally likely and +exactly two of them will create an edge + + align:start position:0% +exactly two of them will create an edge + + + align:start position:0% +exactly two of them will create an edge +that falls in G + + align:start position:0% + + + + align:start position:0% + +Prime now knowing this by linearity of + + align:start position:0% + + + + align:start position:0% + +expectations the number of + + align:start position:0% +expectations the number of + + + align:start position:0% +expectations the number of +edges + + align:start position:0% +edges + + + align:start position:0% +edges +of G + + align:start position:0% + + + + align:start position:0% + +Prime here G Prime is a random subgraph + + align:start position:0% +Prime here G Prime is a random subgraph + + + align:start position:0% +Prime here G Prime is a random subgraph +right where G is given G Prime depends + + align:start position:0% +right where G is given G Prime depends + + + align:start position:0% +right where G is given G Prime depends +on the coin flips that we made to assign + + align:start position:0% +on the coin flips that we made to assign + + + align:start position:0% +on the coin flips that we made to assign +colors so it's a random subgraph so the + + align:start position:0% +colors so it's a random subgraph so the + + + align:start position:0% +colors so it's a random subgraph so the +number of edges of G Prime is a random + + align:start position:0% +number of edges of G Prime is a random + + + align:start position:0% +number of edges of G Prime is a random +variable but this random variable has an + + align:start position:0% +variable but this random variable has an + + + align:start position:0% +variable but this random variable has an +expectation and we can compute this + + align:start position:0% +expectation and we can compute this + + + align:start position:0% +expectation and we can compute this +expectation using linear of expectations + + align:start position:0% +expectation using linear of expectations + + + align:start position:0% +expectation using linear of expectations +because each Edge Falls in G Prime with + + align:start position:0% +because each Edge Falls in G Prime with + + + align:start position:0% +because each Edge Falls in G Prime with +probability 1/2 and therefore the total + + align:start position:0% +probability 1/2 and therefore the total + + + align:start position:0% +probability 1/2 and therefore the total +expected number of edges in gpre is + + align:start position:0% +expected number of edges in gpre is + + + align:start position:0% +expected number of edges in gpre is +m/2 this is the expectation this is what + + align:start position:0% +m/2 this is the expectation this is what + + + align:start position:0% +m/2 this is the expectation this is what +happens on + + align:start position:0% + + + + align:start position:0% + +average + + align:start position:0% +average + + + align:start position:0% +average +does some instance + + align:start position:0% + + + + align:start position:0% + +of G + + align:start position:0% +of G + + + align:start position:0% +of G +Prime + + align:start position:0% +Prime + + + align:start position:0% +Prime +has at least m/2 + + align:start position:0% +has at least m/2 + + + align:start position:0% +has at least m/2 +edges right if on average we get M over2 + + align:start position:0% +edges right if on average we get M over2 + + + align:start position:0% +edges right if on average we get M over2 +edges then there must be some instance + + align:start position:0% +edges then there must be some instance + + + align:start position:0% +edges then there must be some instance +with at least M over2 edges and this G + + align:start position:0% + + + + align:start position:0% + +Prime is what we're looking + + align:start position:0% + + + + align:start position:0% + +for it has at least M over two edges and + + align:start position:0% +for it has at least M over two edges and + + + align:start position:0% +for it has at least M over two edges and +it is bipartite because we've kept all + + align:start position:0% +it is bipartite because we've kept all + + + align:start position:0% +it is bipartite because we've kept all +the edges from the black side to the + + align:start position:0% +the edges from the black side to the + + + align:start position:0% +the edges from the black side to the +white side and so this G Prime is + + align:start position:0% +white side and so this G Prime is + + + align:start position:0% +white side and so this G Prime is +bipartite this finishes the proof of the + + align:start position:0% +bipartite this finishes the proof of the + + + align:start position:0% +bipartite this finishes the proof of the +theorem and you see that by introducing + + align:start position:0% +theorem and you see that by introducing + + + align:start position:0% +theorem and you see that by introducing +Randomness we can prove something about + + align:start position:0% +Randomness we can prove something about + + + align:start position:0% +Randomness we can prove something about +the existence of a structure with + + align:start position:0% +the existence of a structure with + + + align:start position:0% +the existence of a structure with +desired properties and it's a hmark of + + align:start position:0% +desired properties and it's a hmark of + + + align:start position:0% +desired properties and it's a hmark of +the probabilistic method and it's an + + align:start position:0% +the probabilistic method and it's an + + + align:start position:0% +the probabilistic method and it's an +important meth me that has lot of + + align:start position:0% +important meth me that has lot of + + + align:start position:0% +important meth me that has lot of +applications and this is one of the + + align:start position:0% +applications and this is one of the + + + align:start position:0% +applications and this is one of the +simplest examples of its applications \ No newline at end of file diff --git a/dfsPKoHv_F4.txt b/dfsPKoHv_F4.txt new file mode 100644 index 0000000000000000000000000000000000000000..d593edd22efa0e5568c06ee59ad3b7083c3edaf6 --- /dev/null +++ b/dfsPKoHv_F4.txt @@ -0,0 +1,15739 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT OpenCourseWare continue to + + align:start position:0% +will help MIT OpenCourseWare continue to + + + align:start position:0% +will help MIT OpenCourseWare continue to +offer high quality educational resources + + align:start position:0% +offer high quality educational resources + + + align:start position:0% +offer high quality educational resources +for free + + align:start position:0% +for free + + + align:start position:0% +for free +to make a donation or view additional + + align:start position:0% +to make a donation or view additional + + + align:start position:0% +to make a donation or view additional +materials from hundreds of MIT courses + + align:start position:0% +materials from hundreds of MIT courses + + + align:start position:0% +materials from hundreds of MIT courses +visit MIT opencourseware at ocw.mit.edu + + align:start position:0% +visit MIT opencourseware at ocw.mit.edu + + + align:start position:0% +visit MIT opencourseware at ocw.mit.edu +so where we left off was you know again + + align:start position:0% +so where we left off was you know again + + + align:start position:0% +so where we left off was you know again +I was telling you a story both + + align:start position:0% +I was telling you a story both + + + align:start position:0% +I was telling you a story both +conceptual and motivational and a little + + align:start position:0% +conceptual and motivational and a little + + + align:start position:0% +conceptual and motivational and a little +bit technical about how we got to the + + align:start position:0% +bit technical about how we got to the + + + align:start position:0% +bit technical about how we got to the +things we're trying to do now as part of + + align:start position:0% +things we're trying to do now as part of + + + align:start position:0% +things we're trying to do now as part of +the center and it involves again both + + align:start position:0% +the center and it involves again both + + + align:start position:0% +the center and it involves again both +the problems we want to solve we want to + + align:start position:0% +the problems we want to solve we want to + + + align:start position:0% +the problems we want to solve we want to +understand what is this common-sense + + align:start position:0% +understand what is this common-sense + + + align:start position:0% +understand what is this common-sense +knowledge about the physical world and + + align:start position:0% +knowledge about the physical world and + + + align:start position:0% +knowledge about the physical world and +the psychological world that's you can + + align:start position:0% +the psychological world that's you can + + + align:start position:0% +the psychological world that's you can +see in some form even in young infants + + align:start position:0% +see in some form even in young infants + + + align:start position:0% +see in some form even in young infants +and what are the learning mechanisms + + align:start position:0% +and what are the learning mechanisms + + + align:start position:0% +and what are the learning mechanisms +that build it and grow it and then + + align:start position:0% +that build it and grow it and then + + + align:start position:0% +that build it and grow it and then +what's the kind of technical ideas that + + align:start position:0% +what's the kind of technical ideas that + + + align:start position:0% +what's the kind of technical ideas that +are going to be also hopefully useful + + align:start position:0% +are going to be also hopefully useful + + + align:start position:0% +are going to be also hopefully useful +for building intelligent robots or other + + align:start position:0% +for building intelligent robots or other + + + align:start position:0% +for building intelligent robots or other +AI systems that can explain on the + + align:start position:0% +AI systems that can explain on the + + + align:start position:0% +AI systems that can explain on the +scientific side how this stuff works all + + align:start position:0% +scientific side how this stuff works all + + + align:start position:0% +scientific side how this stuff works all +right so that was all this business and + + align:start position:0% +right so that was all this business and + + + align:start position:0% +right so that was all this business and +what I was suggesting or I'll start to + + align:start position:0% +what I was suggesting or I'll start to + + + align:start position:0% +what I was suggesting or I'll start to +suggest here now is that it goes back to + + align:start position:0% +suggest here now is that it goes back to + + + align:start position:0% +suggest here now is that it goes back to +that quote I gave at the beginning from + + align:start position:0% +that quote I gave at the beginning from + + + align:start position:0% +that quote I gave at the beginning from +Craik right the guy who in 1943 wrote + + align:start position:0% +Craik right the guy who in 1943 wrote + + + align:start position:0% +Craik right the guy who in 1943 wrote +this book called the nature of + + align:start position:0% +this book called the nature of + + + align:start position:0% +this book called the nature of +explanation and he was saying that's the + + align:start position:0% +explanation and he was saying that's the + + + align:start position:0% +explanation and he was saying that's the +essence of intelligence is this ability + + align:start position:0% +essence of intelligence is this ability + + + align:start position:0% +essence of intelligence is this ability +to build models that allow you to + + align:start position:0% +to build models that allow you to + + + align:start position:0% +to build models that allow you to +explain the world + + align:start position:0% +explain the world + + + align:start position:0% +explain the world +- then reason simulate plan and so on + + align:start position:0% +- then reason simulate plan and so on + + + align:start position:0% +- then reason simulate plan and so on +right and I think we need tools for + + align:start position:0% +right and I think we need tools for + + + align:start position:0% +right and I think we need tools for +understanding how the brain is a + + align:start position:0% +understanding how the brain is a + + + align:start position:0% +understanding how the brain is a +modeling engine or you know an + + align:start position:0% +modeling engine or you know an + + + align:start position:0% +modeling engine or you know an +explaining engine or should we get a + + align:start position:0% +explaining engine or should we get a + + + align:start position:0% +explaining engine or should we get a +little bit recursive about it since what + + align:start position:0% +little bit recursive about it since what + + + align:start position:0% +little bit recursive about it since what +we're doing in science is also an + + align:start position:0% +we're doing in science is also an + + + align:start position:0% +we're doing in science is also an +explanatory activity we need modeling + + align:start position:0% +explanatory activity we need modeling + + + align:start position:0% +explanatory activity we need modeling +engines which in which we can build + + align:start position:0% +engines which in which we can build + + + align:start position:0% +engines which in which we can build +models of the brain as a modeling engine + + align:start position:0% +models of the brain as a modeling engine + + + align:start position:0% +models of the brain as a modeling engine +and that's where the probabilistic + + align:start position:0% +and that's where the probabilistic + + + align:start position:0% +and that's where the probabilistic +programs are gonna come so part of why I + + align:start position:0% +programs are gonna come so part of why I + + + align:start position:0% +programs are gonna come so part of why I +spent a while at the in the morning + + align:start position:0% +spent a while at the in the morning + + + align:start position:0% +spent a while at the in the morning +talking about these graphical models and + + align:start position:0% +talking about these graphical models and + + + align:start position:0% +talking about these graphical models and +the ways that we tried and I think may + + align:start position:0% +the ways that we tried and I think may + + + align:start position:0% +the ways that we tried and I think may +progress on but ultimately we're + + align:start position:0% +progress on but ultimately we're + + + align:start position:0% +progress on but ultimately we're +dissatisfied with talking about how + + align:start position:0% +dissatisfied with talking about how + + + align:start position:0% +dissatisfied with talking about how +we're modeling various aspects of + + align:start position:0% +we're modeling various aspects of + + + align:start position:0% +we're modeling various aspects of +cognition with these kinds of graphical + + align:start position:0% +cognition with these kinds of graphical + + + align:start position:0% +cognition with these kinds of graphical +models right I put up it didn't say too + + align:start position:0% +models right I put up it didn't say too + + + align:start position:0% +models right I put up it didn't say too +much about the technical details that's + + align:start position:0% +much about the technical details that's + + + align:start position:0% +much about the technical details that's +fine you can read a lot about it or not + + align:start position:0% +fine you can read a lot about it or not + + + align:start position:0% +fine you can read a lot about it or not +but these ways of using graphs mostly + + align:start position:0% +but these ways of using graphs mostly + + + align:start position:0% +but these ways of using graphs mostly +directed graphs to capture something + + align:start position:0% +directed graphs to capture something + + + align:start position:0% +directed graphs to capture something +about the structure of the world and + + align:start position:0% +about the structure of the world and + + + align:start position:0% +about the structure of the world and +then you put probabilities on it in some + + align:start position:0% +then you put probabilities on it in some + + + align:start position:0% +then you put probabilities on it in some +way like a diffusion process or a noisy + + align:start position:0% +way like a diffusion process or a noisy + + + align:start position:0% +way like a diffusion process or a noisy +transmission process for a food web + + align:start position:0% +transmission process for a food web + + + align:start position:0% +transmission process for a food web +that's a style of reasoning that is + + align:start position:0% +that's a style of reasoning that is + + + align:start position:0% +that's a style of reasoning that is +sometimes goes by the name of Bayesian + + align:start position:0% +sometimes goes by the name of Bayesian + + + align:start position:0% +sometimes goes by the name of Bayesian +networks for causal graphical models + + align:start position:0% +networks for causal graphical models + + + align:start position:0% +networks for causal graphical models +it's been it's been hugely influential + + align:start position:0% +it's been it's been hugely influential + + + align:start position:0% +it's been it's been hugely influential +in computer science many different + + align:start position:0% +in computer science many different + + + align:start position:0% +in computer science many different +fields not just AI and many fields + + align:start position:0% +fields not just AI and many fields + + + align:start position:0% +fields not just AI and many fields +outside of computer science not just + + align:start position:0% +outside of computer science not just + + + align:start position:0% +outside of computer science not just +cognitive science neuroscience in many + + align:start position:0% +cognitive science neuroscience in many + + + align:start position:0% +cognitive science neuroscience in many +areas of science and engineering here + + align:start position:0% +areas of science and engineering here + + + align:start position:0% +areas of science and engineering here +are just a few examples of some Bayesian + + align:start position:0% +are just a few examples of some Bayesian + + + align:start position:0% +are just a few examples of some Bayesian +networks you get if you search on Google + + align:start position:0% +networks you get if you search on Google + + + align:start position:0% +networks you get if you search on Google +image for Bayesian networks right and if + + align:start position:0% +image for Bayesian networks right and if + + + align:start position:0% +image for Bayesian networks right and if +you look carefully you'll see they come + + align:start position:0% +you look carefully you'll see they come + + + align:start position:0% +you look carefully you'll see they come +from biology economics many at chemical + + align:start position:0% +from biology economics many at chemical + + + align:start position:0% +from biology economics many at chemical +engineering whatever they're due to many + + align:start position:0% +engineering whatever they're due to many + + + align:start position:0% +engineering whatever they're due to many +people maybe more than anyone the person + + align:start position:0% +people maybe more than anyone the person + + + align:start position:0% +people maybe more than anyone the person +who's most associated with this idea and + + align:start position:0% +who's most associated with this idea and + + + align:start position:0% +who's most associated with this idea and +with the name Bayesian networks is Judea + + align:start position:0% +with the name Bayesian networks is Judea + + + align:start position:0% +with the name Bayesian networks is Judea +pearl he received the Turing award which + + align:start position:0% +pearl he received the Turing award which + + + align:start position:0% +pearl he received the Turing award which +is like the highest award in computer + + align:start position:0% +is like the highest award in computer + + + align:start position:0% +is like the highest award in computer +science you know this is a language that + + align:start position:0% +science you know this is a language that + + + align:start position:0% +science you know this is a language that +we were using and all the prelate of + + align:start position:0% +we were using and all the prelate of + + + align:start position:0% +we were using and all the prelate of +projects you saw up until now in some + + align:start position:0% +projects you saw up until now in some + + + align:start position:0% +projects you saw up until now in some +form that we and many others used + + align:start position:0% +form that we and many others used + + + align:start position:0% +form that we and many others used +because they provide a powerful set of + + align:start position:0% +because they provide a powerful set of + + + align:start position:0% +because they provide a powerful set of +tools for the general purpose tools + + align:start position:0% +tools for the general purpose tools + + + align:start position:0% +tools for the general purpose tools +right it goes back to this dream of + + align:start position:0% +right it goes back to this dream of + + + align:start position:0% +right it goes back to this dream of +building general-purpose systems for + + align:start position:0% +building general-purpose systems for + + + align:start position:0% +building general-purpose systems for +understanding the world + + align:start position:0% +understanding the world + + + align:start position:0% +understanding the world +so these provide general-purpose + + align:start position:0% +so these provide general-purpose + + + align:start position:0% +so these provide general-purpose +languages for representing causal + + align:start position:0% +languages for representing causal + + + align:start position:0% +languages for representing causal +structure debate you know I'll say a + + align:start position:0% +structure debate you know I'll say a + + + align:start position:0% +structure debate you know I'll say a +little bit more about that and + + align:start position:0% +little bit more about that and + + + align:start position:0% +little bit more about that and +general-purpose algorithms for doing the + + align:start position:0% +general-purpose algorithms for doing the + + + align:start position:0% +general-purpose algorithms for doing the +probabilistic inference on this so we + + align:start position:0% +probabilistic inference on this so we + + + align:start position:0% +probabilistic inference on this so we +talked about ways of combining + + align:start position:0% +talked about ways of combining + + + align:start position:0% +talked about ways of combining +sophisticated statistical inference with + + align:start position:0% +sophisticated statistical inference with + + + align:start position:0% +sophisticated statistical inference with +knowledge representation that's causal + + align:start position:0% +knowledge representation that's causal + + + align:start position:0% +knowledge representation that's causal +and compositional these models I'll just + + align:start position:0% +and compositional these models I'll just + + + align:start position:0% +and compositional these models I'll just +tell you a little bit about the one in + + align:start position:0% +tell you a little bit about the one in + + + align:start position:0% +tell you a little bit about the one in +the upper left up there that thing that + + align:start position:0% +the upper left up there that thing that + + + align:start position:0% +the upper left up there that thing that +says diseases and symptoms it is causal + + align:start position:0% +says diseases and symptoms it is causal + + + align:start position:0% +says diseases and symptoms it is causal +it is compositional it does support + + align:start position:0% +it is compositional it does support + + + align:start position:0% +it is compositional it does support +probabilistic inference and it was the + + align:start position:0% +probabilistic inference and it was the + + + align:start position:0% +probabilistic inference and it was the +heart of why we were doing what we were + + align:start position:0% +heart of why we were doing what we were + + + align:start position:0% +heart of why we were doing what we were +doing and showing you how different + + align:start position:0% +doing and showing you how different + + + align:start position:0% +doing and showing you how different +kinds of causal graphical models + + align:start position:0% +kinds of causal graphical models + + + align:start position:0% +kinds of causal graphical models +basically could capture different modes + + align:start position:0% +basically could capture different modes + + + align:start position:0% +basically could capture different modes +of people's reasoning and the idea that + + align:start position:0% +of people's reasoning and the idea that + + + align:start position:0% +of people's reasoning and the idea that +maybe learning about different domains + + align:start position:0% +maybe learning about different domains + + + align:start position:0% +maybe learning about different domains +was learning those different kinds of + + align:start position:0% +was learning those different kinds of + + + align:start position:0% +was learning those different kinds of +graph structures so let me say a little + + align:start position:0% +graph structures so let me say a little + + + align:start position:0% +graph structures so let me say a little +bit of how it works and then why it's + + align:start position:0% +bit of how it works and then why it's + + + align:start position:0% +bit of how it works and then why it's +not enough cuz it really isn't enough I + + align:start position:0% +not enough cuz it really isn't enough I + + + align:start position:0% +not enough cuz it really isn't enough I +mean it's it's it's the right start it's + + align:start position:0% +mean it's it's it's the right start it's + + + align:start position:0% +mean it's it's it's the right start it's +definitely in the right direction but we + + align:start position:0% +definitely in the right direction but we + + + align:start position:0% +definitely in the right direction but we +need to go beyond it that's where the + + align:start position:0% +need to go beyond it that's where the + + + align:start position:0% +need to go beyond it that's where the +probable stick programs come in so look + + align:start position:0% +probable stick programs come in so look + + + align:start position:0% +probable stick programs come in so look +at that network up there on the upper + + align:start position:0% +at that network up there on the upper + + + align:start position:0% +at that network up there on the upper +left it's some it's a what's one of the + + align:start position:0% +left it's some it's a what's one of the + + + align:start position:0% +left it's some it's a what's one of the +most famous Bayesian networks it's a + + align:start position:0% +most famous Bayesian networks it's a + + + align:start position:0% +most famous Bayesian networks it's a +textbook example it was one of the first + + align:start position:0% +textbook example it was one of the first + + + align:start position:0% +textbook example it was one of the first +actually implemented pay I systems was + + align:start position:0% +actually implemented pay I systems was + + + align:start position:0% +actually implemented pay I systems was +based on this for a system for medical + + align:start position:0% +based on this for a system for medical + + + align:start position:0% +based on this for a system for medical +diagnosis sort of a simple approximation + + align:start position:0% +diagnosis sort of a simple approximation + + + align:start position:0% +diagnosis sort of a simple approximation +to what a general practitioner might be + + align:start position:0% +to what a general practitioner might be + + + align:start position:0% +to what a general practitioner might be +doing if a patient comes in and reports + + align:start position:0% +doing if a patient comes in and reports + + + align:start position:0% +doing if a patient comes in and reports +some pattern of symptoms and they want + + align:start position:0% +some pattern of symptoms and they want + + + align:start position:0% +some pattern of symptoms and they want +to figure out what's wrong + + align:start position:0% +to figure out what's wrong + + + align:start position:0% +to figure out what's wrong +right so diagnosis of a disease to + + align:start position:0% +right so diagnosis of a disease to + + + align:start position:0% +right so diagnosis of a disease to +explain the symptoms the the the graph + + align:start position:0% +explain the symptoms the the the graph + + + align:start position:0% +explain the symptoms the the the graph +is a bipartite graph so two sets of + + align:start position:0% +is a bipartite graph so two sets of + + + align:start position:0% +is a bipartite graph so two sets of +nodes with the arrows again going down + + align:start position:0% +nodes with the arrows again going down + + + align:start position:0% +nodes with the arrows again going down +in the causal direction the the bottom + + align:start position:0% +in the causal direction the the bottom + + + align:start position:0% +in the causal direction the the bottom +layer the symptoms are the things that + + align:start position:0% +layer the symptoms are the things that + + + align:start position:0% +layer the symptoms are the things that +you can nominally observe right a + + align:start position:0% +you can nominally observe right a + + + align:start position:0% +you can nominally observe right a +patient comes in reporting some symptoms + + align:start position:0% +patient comes in reporting some symptoms + + + align:start position:0% +patient comes in reporting some symptoms +not all are observed but others maybe + + align:start position:0% +not all are observed but others maybe + + + align:start position:0% +not all are observed but others maybe +are things that you could test like a + + align:start position:0% +are things that you could test like a + + + align:start position:0% +are things that you could test like a +medical test results and then there's + + align:start position:0% +medical test results and then there's + + + align:start position:0% +medical test results and then there's +the top level is this level of latent + + align:start position:0% +the top level is this level of latent + + + align:start position:0% +the top level is this level of latent +structure the causes the things that + + align:start position:0% +structure the causes the things that + + + align:start position:0% +structure the causes the things that +cause the symptoms the arrows represent + + align:start position:0% +cause the symptoms the arrows represent + + + align:start position:0% +cause the symptoms the arrows represent +basically which diseases caused which + + align:start position:0% +basically which diseases caused which + + + align:start position:0% +basically which diseases caused which +symptoms in this model there's roughly + + align:start position:0% +symptoms in this model there's roughly + + + align:start position:0% +symptoms in this model there's roughly +five hundred six hundred diseases you + + align:start position:0% +five hundred six hundred diseases you + + + align:start position:0% +five hundred six hundred diseases you +know the common ish ones not all that + + align:start position:0% +know the common ish ones not all that + + + align:start position:0% +know the common ish ones not all that +common and four thousand symptoms so + + align:start position:0% +common and four thousand symptoms so + + + align:start position:0% +common and four thousand symptoms so +it's a big model and in some sense you + + align:start position:0% +it's a big model and in some sense you + + + align:start position:0% +it's a big model and in some sense you +can think of it as a big probability + + align:start position:0% +can think of it as a big probability + + + align:start position:0% +can think of it as a big probability +model right it's a way of specifying a + + align:start position:0% +model right it's a way of specifying a + + + align:start position:0% +model right it's a way of specifying a +joint distribution on this you know for + + align:start position:0% +joint distribution on this you know for + + + align:start position:0% +joint distribution on this you know for +4600 dimensional space but it's a very + + align:start position:0% +4600 dimensional space but it's a very + + + align:start position:0% +4600 dimensional space but it's a very +particular one that's causally + + align:start position:0% +particular one that's causally + + + align:start position:0% +particular one that's causally +structured it represents only the + + align:start position:0% +structured it represents only the + + + align:start position:0% +structured it represents only the +minimal causal dependencies and really + + align:start position:0% +minimal causal dependencies and really + + + align:start position:0% +minimal causal dependencies and really +the only the minimal probabilistic + + align:start position:0% +the only the minimal probabilistic + + + align:start position:0% +the only the minimal probabilistic +dependencies that sparsity is really + + align:start position:0% +dependencies that sparsity is really + + + align:start position:0% +dependencies that sparsity is really +important for how you use it whether + + align:start position:0% +important for how you use it whether + + + align:start position:0% +important for how you use it whether +you're talking about inference or + + align:start position:0% +you're talking about inference or + + + align:start position:0% +you're talking about inference or +learning so inference means observing + + align:start position:0% +learning so inference means observing + + + align:start position:0% +learning so inference means observing +patterns of symptoms or just observing + + align:start position:0% +patterns of symptoms or just observing + + + align:start position:0% +patterns of symptoms or just observing +the values of some of those variables + + align:start position:0% +the values of some of those variables + + + align:start position:0% +the values of some of those variables +and making guesses about the others like + + align:start position:0% +and making guesses about the others like + + + align:start position:0% +and making guesses about the others like +observing some symptoms and making + + align:start position:0% +observing some symptoms and making + + + align:start position:0% +observing some symptoms and making +guesses about the diseases that are most + + align:start position:0% +guesses about the diseases that are most + + + align:start position:0% +guesses about the diseases that are most +likely to have explained to those or you + + align:start position:0% +likely to have explained to those or you + + + align:start position:0% +likely to have explained to those or you +might make a prediction about other + + align:start position:0% +might make a prediction about other + + + align:start position:0% +might make a prediction about other +symptoms you could observe so you could + + align:start position:0% +symptoms you could observe so you could + + + align:start position:0% +symptoms you could observe so you could +kind of go up and then back down you + + align:start position:0% +kind of go up and then back down you + + + align:start position:0% +kind of go up and then back down you +could say well from these symptoms I + + align:start position:0% +could say well from these symptoms I + + + align:start position:0% +could say well from these symptoms I +think the patient might have one of + + align:start position:0% +think the patient might have one of + + + align:start position:0% +think the patient might have one of +these two rare diseases I don't know + + align:start position:0% +these two rare diseases I don't know + + + align:start position:0% +these two rare diseases I don't know +which one I better go in whatever but if + + align:start position:0% +which one I better go in whatever but if + + + align:start position:0% +which one I better go in whatever but if +it was this disease then it would + + align:start position:0% +it was this disease then it would + + + align:start position:0% +it was this disease then it would +predict that symptom or that test maybe + + align:start position:0% +predict that symptom or that test maybe + + + align:start position:0% +predict that symptom or that test maybe +but this disease wouldn't so then that + + align:start position:0% +but this disease wouldn't so then that + + + align:start position:0% +but this disease wouldn't so then that +suggests a way to plan an action you + + align:start position:0% +suggests a way to plan an action you + + + align:start position:0% +suggests a way to plan an action you +could take to figure things out and then + + align:start position:0% +could take to figure things out and then + + + align:start position:0% +could take to figure things out and then +I could go test for that symptom and + + align:start position:0% +I could go test for that symptom and + + + align:start position:0% +I could go test for that symptom and +that would tell me which of these + + align:start position:0% +that would tell me which of these + + + align:start position:0% +that would tell me which of these +diseases the patient has they're also + + align:start position:0% +diseases the patient has they're also + + + align:start position:0% +diseases the patient has they're also +useful in planning other kinds of you + + align:start position:0% +useful in planning other kinds of you + + + align:start position:0% +useful in planning other kinds of you +know treatments interventions like if + + align:start position:0% +know treatments interventions like if + + + align:start position:0% +know treatments interventions like if +you want to cure someone again we all + + align:start position:0% +you want to cure someone again we all + + + align:start position:0% +you want to cure someone again we all +know this intuitively you should try to + + align:start position:0% +know this intuitively you should try to + + + align:start position:0% +know this intuitively you should try to +cure the disease not the symptom right + + align:start position:0% +cure the disease not the symptom right + + + align:start position:0% +cure the disease not the symptom right +if you know if you have some way to act + + align:start position:0% +if you know if you have some way to act + + + align:start position:0% +if you know if you have some way to act +it to change the state of one of those + + align:start position:0% +it to change the state of one of those + + + align:start position:0% +it to change the state of one of those +disease variables to kind of turn it off + + align:start position:0% +disease variables to kind of turn it off + + + align:start position:0% +disease variables to kind of turn it off +it's you hopefully that reasonably that + + align:start position:0% +it's you hopefully that reasonably that + + + align:start position:0% +it's you hopefully that reasonably that +should relieve the symptoms if that + + align:start position:0% +should relieve the symptoms if that + + + align:start position:0% +should relieve the symptoms if that +disease gets turned off these symptoms + + align:start position:0% +disease gets turned off these symptoms + + + align:start position:0% +disease gets turned off these symptoms +are turned off whereas just treating the + + align:start position:0% +are turned off whereas just treating the + + + align:start position:0% +are turned off whereas just treating the +symptom like taking Advil for a headache + + align:start position:0% +symptom like taking Advil for a headache + + + align:start position:0% +symptom like taking Advil for a headache +is fine if that's all the problem is but + + align:start position:0% +is fine if that's all the problem is but + + + align:start position:0% +is fine if that's all the problem is but +if you if it's being caused by something + + align:start position:0% +if you if it's being caused by something + + + align:start position:0% +if you if it's being caused by something +you know god forbid like a brain tumor + + align:start position:0% +you know god forbid like a brain tumor + + + align:start position:0% +you know god forbid like a brain tumor +it's not going to help okay it's not + + align:start position:0% +it's not going to help okay it's not + + + align:start position:0% +it's not going to help okay it's not +gonna cure the problem in the long term + + align:start position:0% +gonna cure the problem in the long term + + + align:start position:0% +gonna cure the problem in the long term +okay so all those patterns of causal + + align:start position:0% +okay so all those patterns of causal + + + align:start position:0% +okay so all those patterns of causal +inference reasoning prediction action + + align:start position:0% +inference reasoning prediction action + + + align:start position:0% +inference reasoning prediction action +planning excavation is a beautiful + + align:start position:0% +planning excavation is a beautiful + + + align:start position:0% +planning excavation is a beautiful +language for capturing all of those you + + align:start position:0% +language for capturing all of those you + + + align:start position:0% +language for capturing all of those you +can automate all those inferences why + + align:start position:0% +can automate all those inferences why + + + align:start position:0% +can automate all those inferences why +isn't it enough then for for capturing + + align:start position:0% +isn't it enough then for for capturing + + + align:start position:0% +isn't it enough then for for capturing +common sense reasoning or this approach + + align:start position:0% +common sense reasoning or this approach + + + align:start position:0% +common sense reasoning or this approach +to cognition which I'm calling the kind + + align:start position:0% +to cognition which I'm calling the kind + + + align:start position:0% +to cognition which I'm calling the kind +of model building explaining part as + + align:start position:0% +of model building explaining part as + + + align:start position:0% +of model building explaining part as +opposed to the the pattern recognition + + align:start position:0% +opposed to the the pattern recognition + + + align:start position:0% +opposed to the the pattern recognition +part I mean again I don't want to get + + align:start position:0% +part I mean again I don't want to get + + + align:start position:0% +part I mean again I don't want to get +too far behind and talking about this + + align:start position:0% +too far behind and talking about this + + + align:start position:0% +too far behind and talking about this +but that example is so rich like if you + + align:start position:0% +but that example is so rich like if you + + + align:start position:0% +but that example is so rich like if you +you can build a neural network you could + + align:start position:0% +you can build a neural network you could + + + align:start position:0% +you can build a neural network you could +just turn the arrows around to learn a + + align:start position:0% +just turn the arrows around to learn a + + + align:start position:0% +just turn the arrows around to learn a +mapping from symptoms to diseases and + + align:start position:0% +mapping from symptoms to diseases and + + + align:start position:0% +mapping from symptoms to diseases and +that would be a pattern classifier right + + align:start position:0% +that would be a pattern classifier right + + + align:start position:0% +that would be a pattern classifier right +so these these two different paradigms + + align:start position:0% +so these these two different paradigms + + + align:start position:0% +so these these two different paradigms +for intelligence as some of the + + align:start position:0% +for intelligence as some of the + + + align:start position:0% +for intelligence as some of the +questions we're getting at and as I will + + align:start position:0% +questions we're getting at and as I will + + + align:start position:0% +questions we're getting at and as I will +show versions of that with some more + + align:start position:0% +show versions of that with some more + + + align:start position:0% +show versions of that with some more +interesting examples in a little bit + + align:start position:0% +interesting examples in a little bit + + + align:start position:0% +interesting examples in a little bit +right there often it's hard it's very + + align:start position:0% +right there often it's hard it's very + + + align:start position:0% +right there often it's hard it's very +subtle and the relations between them + + align:start position:0% +subtle and the relations between them + + + align:start position:0% +subtle and the relations between them +are are quite valuable so one way to + + align:start position:0% +are are quite valuable so one way to + + + align:start position:0% +are are quite valuable so one way to +work with such a model for example or + + align:start position:0% +work with such a model for example or + + + align:start position:0% +work with such a model for example or +one nice way I mean I mentioned a lot of + + align:start position:0% +one nice way I mean I mentioned a lot of + + + align:start position:0% +one nice way I mean I mentioned a lot of +people want to know and I'll keep + + align:start position:0% +people want to know and I'll keep + + + align:start position:0% +people want to know and I'll keep +talking about this for the rest of the + + align:start position:0% +talking about this for the rest of the + + + align:start position:0% +talking about this for the rest of the +hour that you can productive ways to + + align:start position:0% +hour that you can productive ways to + + + align:start position:0% +hour that you can productive ways to +combine these causal generative models + + align:start position:0% +combine these causal generative models + + + align:start position:0% +combine these causal generative models +with more you know pattern recognition + + align:start position:0% +with more you know pattern recognition + + + align:start position:0% +with more you know pattern recognition +approaches in some for some classes of + + align:start position:0% +approaches in some for some classes of + + + align:start position:0% +approaches in some for some classes of +this model it's it's but there are there + + align:start position:0% +this model it's it's but there are there + + + align:start position:0% +this model it's it's but there are there +are always general-purpose algorithms + + align:start position:0% +are always general-purpose algorithms + + + align:start position:0% +are always general-purpose algorithms +that can support these inferences that + + align:start position:0% +that can support these inferences that + + + align:start position:0% +that can support these inferences that +can tell you what diseases you're likely + + align:start position:0% +can tell you what diseases you're likely + + + align:start position:0% +can tell you what diseases you're likely +to have given what symptoms but in some + + align:start position:0% +to have given what symptoms but in some + + + align:start position:0% +to have given what symptoms but in some +cases they could be very fast in other + + align:start position:0% +cases they could be very fast in other + + + align:start position:0% +cases they could be very fast in other +cases they could be very slow whereas if + + align:start position:0% +cases they could be very slow whereas if + + + align:start position:0% +cases they could be very slow whereas if +you could imagine trying to learn a + + align:start position:0% +you could imagine trying to learn a + + + align:start position:0% +you could imagine trying to learn a +network that looks just like that only + + align:start position:0% +network that looks just like that only + + + align:start position:0% +network that looks just like that only +the arrows go up so they implement a + + align:start position:0% +the arrows go up so they implement a + + + align:start position:0% +the arrows go up so they implement a +mapping from data to diseases that could + + align:start position:0% +mapping from data to diseases that could + + + align:start position:0% +mapping from data to diseases that could +help to do to do much faster inference + + align:start position:0% +help to do to do much faster inference + + + align:start position:0% +help to do to do much faster inference +in the cases where that's possible so + + align:start position:0% +in the cases where that's possible so + + + align:start position:0% +in the cases where that's possible so +that's just one example of where you + + align:start position:0% +that's just one example of where you + + + align:start position:0% +that's just one example of where you +know a pair of a model which might be + + align:start position:0% +know a pair of a model which might be + + + align:start position:0% +know a pair of a model which might be +not a crazy way to think about for + + align:start position:0% +not a crazy way to think about for + + + align:start position:0% +not a crazy way to think about for +example more generally the way top-down + + align:start position:0% +example more generally the way top-down + + + align:start position:0% +example more generally the way top-down +and bottom-up connections work in the + + align:start position:0% +and bottom-up connections work in the + + + align:start position:0% +and bottom-up connections work in the +brain I'll I'll take that a little bit + + align:start position:0% +brain I'll I'll take that a little bit + + + align:start position:0% +brain I'll I'll take that a little bit +more literally in a vision example in a + + align:start position:0% +more literally in a vision example in a + + + align:start position:0% +more literally in a vision example in a +second but so there's a lot you can get + + align:start position:0% +second but so there's a lot you can get + + + align:start position:0% +second but so there's a lot you can get +from studying these causal graphical + + align:start position:0% +from studying these causal graphical + + + align:start position:0% +from studying these causal graphical +models including some version of what it + + align:start position:0% +models including some version of what it + + + align:start position:0% +models including some version of what it +is for the mind to explain the world and + + align:start position:0% +is for the mind to explain the world and + + + align:start position:0% +is for the mind to explain the world and +how that explanation and pattern + + align:start position:0% +how that explanation and pattern + + + align:start position:0% +how that explanation and pattern +recognition approach can work together + + align:start position:0% +recognition approach can work together + + + align:start position:0% +recognition approach can work together +but it's not enough to really get at the + + align:start position:0% +but it's not enough to really get at the + + + align:start position:0% +but it's not enough to really get at the +at the heart of common-sense the the + + align:start position:0% +at the heart of common-sense the the + + + align:start position:0% +at the heart of common-sense the the +mental generative models we build are + + align:start position:0% +mental generative models we build are + + + align:start position:0% +mental generative models we build are +more richly structured they're more like + + align:start position:0% +more richly structured they're more like + + + align:start position:0% +more richly structured they're more like +programs what do I mean by that well + + align:start position:0% +programs what do I mean by that well + + + align:start position:0% +programs what do I mean by that well +here I'm giving a bunch of examples of + + align:start position:0% +here I'm giving a bunch of examples of + + + align:start position:0% +here I'm giving a bunch of examples of +scientific theories or models not + + align:start position:0% +scientific theories or models not + + + align:start position:0% +scientific theories or models not +common-sense ones but I think the same + + align:start position:0% +common-sense ones but I think the same + + + align:start position:0% +common-sense ones but I think the same +idea applies Wiis of again explaining + + align:start position:0% +idea applies Wiis of again explaining + + + align:start position:0% +idea applies Wiis of again explaining +the world not just describing the + + align:start position:0% +the world not just describing the + + + align:start position:0% +the world not just describing the +pattern so we went at the beginning + + align:start position:0% +pattern so we went at the beginning + + + align:start position:0% +pattern so we went at the beginning +through Newton's laws versus Kepler's + + align:start position:0% +through Newton's laws versus Kepler's + + + align:start position:0% +through Newton's laws versus Kepler's +laws that's just one example and you + + align:start position:0% +laws that's just one example and you + + + align:start position:0% +laws that's just one example and you +might not a flood of those laws as a + + align:start position:0% +might not a flood of those laws as a + + + align:start position:0% +might not a flood of those laws as a +program but there's certainly not a + + align:start position:0% +program but there's certainly not a + + + align:start position:0% +program but there's certainly not a +graph right on the on the first slide + + align:start position:0% +graph right on the on the first slide + + + align:start position:0% +graph right on the on the first slide +when I showed Newton's laws there was a + + align:start position:0% +when I showed Newton's laws there was a + + + align:start position:0% +when I showed Newton's laws there was a +combination there was a bunch of symbols + + align:start position:0% +combination there was a bunch of symbols + + + align:start position:0% +combination there was a bunch of symbols +statements in English some math right + + align:start position:0% +statements in English some math right + + + align:start position:0% +statements in English some math right +but what it comes down to is basically a + + align:start position:0% +but what it comes down to is basically a + + + align:start position:0% +but what it comes down to is basically a +set of pieces of code that you could run + + align:start position:0% +set of pieces of code that you could run + + + align:start position:0% +set of pieces of code that you could run +to generate the orbits right it doesn't + + align:start position:0% +to generate the orbits right it doesn't + + + align:start position:0% +to generate the orbits right it doesn't +describe the sheep or the the velocities + + align:start position:0% +describe the sheep or the the velocities + + + align:start position:0% +describe the sheep or the the velocities +but it's a machine that you plug in some + + align:start position:0% +but it's a machine that you plug in some + + + align:start position:0% +but it's a machine that you plug in some +things you plug in some masses some + + align:start position:0% +things you plug in some masses some + + + align:start position:0% +things you plug in some masses some +objects some initial conditions and you + + align:start position:0% +objects some initial conditions and you + + + align:start position:0% +objects some initial conditions and you +press run and it generates the orbits + + align:start position:0% +press run and it generates the orbits + + + align:start position:0% +press run and it generates the orbits +just like what you're seeing there + + align:start position:0% +just like what you're seeing there + + + align:start position:0% +just like what you're seeing there +although those probably weren't + + align:start position:0% +although those probably weren't + + + align:start position:0% +although those probably weren't +generated that's a justice oh okay + + align:start position:0% +generated that's a justice oh okay + + + align:start position:0% +generated that's a justice oh okay +that's more like Kepler or Ptolemy but + + align:start position:0% +that's more like Kepler or Ptolemy but + + + align:start position:0% +that's more like Kepler or Ptolemy but +anyway but you know it's a powerful + + align:start position:0% +anyway but you know it's a powerful + + + align:start position:0% +anyway but you know it's a powerful +machine it's a machine which if you put + + align:start position:0% +machine it's a machine which if you put + + + align:start position:0% +machine it's a machine which if you put +down the right masses in the right + + align:start position:0% +down the right masses in the right + + + align:start position:0% +down the right masses in the right +position they don't just all go around + + align:start position:0% +position they don't just all go around + + + align:start position:0% +position they don't just all go around +in ellipses some of them are like moons + + align:start position:0% +in ellipses some of them are like moons + + + align:start position:0% +in ellipses some of them are like moons +and they will go around the things that + + align:start position:0% +and they will go around the things that + + + align:start position:0% +and they will go around the things that +will go around the others right and some + + align:start position:0% +will go around the others right and some + + + align:start position:0% +will go around the others right and some +of them will be like apples on the earth + + align:start position:0% +of them will be like apples on the earth + + + align:start position:0% +of them will be like apples on the earth +and they won't go around anything + + align:start position:0% +and they won't go around anything + + + align:start position:0% +and they won't go around anything +they'll just fall down right so that's + + align:start position:0% +they'll just fall down right so that's + + + align:start position:0% +they'll just fall down right so that's +the powerful machine and in the really + + align:start position:0% +the powerful machine and in the really + + + align:start position:0% +the powerful machine and in the really +simplest cases that machine those + + align:start position:0% +simplest cases that machine those + + + align:start position:0% +simplest cases that machine those +equations can be solved analytically + + align:start position:0% +equations can be solved analytically + + + align:start position:0% +equations can be solved analytically +right you can use calculus or other + + align:start position:0% +right you can use calculus or other + + + align:start position:0% +right you can use calculus or other +methods of analysis like Newton did he + + align:start position:0% +methods of analysis like Newton did he + + + align:start position:0% +methods of analysis like Newton did he +didn't have a computer and you can show + + align:start position:0% +didn't have a computer and you can show + + + align:start position:0% +didn't have a computer and you can show +that for two a two-body system one + + align:start position:0% +that for two a two-body system one + + + align:start position:0% +that for two a two-body system one +planet and one Sun you can solve those + + align:start position:0% +planet and one Sun you can solve those + + + align:start position:0% +planet and one Sun you can solve those +equations to show that you get Kepler's + + align:start position:0% +equations to show that you get Kepler's + + + align:start position:0% +equations to show that you get Kepler's +law amazing and if you if two under the + + align:start position:0% +law amazing and if you if two under the + + + align:start position:0% +law amazing and if you if two under the +approximation that you ignore that only + + align:start position:0% +approximation that you ignore that only + + + align:start position:0% +approximation that you ignore that only +the Sun is you know for every other + + align:start position:0% +the Sun is you know for every other + + + align:start position:0% +the Sun is you know for every other +planet it's only the Sun that's exerting + + align:start position:0% +planet it's only the Sun that's exerting + + + align:start position:0% +planet it's only the Sun that's exerting +a significant influence you can describe + + align:start position:0% +a significant influence you can describe + + + align:start position:0% +a significant influence you can describe +all of Kepler's laws this way but once + + align:start position:0% +all of Kepler's laws this way but once + + + align:start position:0% +all of Kepler's laws this way but once +you have more than two bodies + + align:start position:0% +you have more than two bodies + + + align:start position:0% +you have more than two bodies +interacting in some complex way like + + align:start position:0% +interacting in some complex way like + + + align:start position:0% +interacting in some complex way like +three masses similar in size near each + + align:start position:0% +three masses similar in size near each + + + align:start position:0% +three masses similar in size near each +other you can't solve the equations + + align:start position:0% +other you can't solve the equations + + + align:start position:0% +other you can't solve the equations +analytically anymore you basically just + + align:start position:0% +analytically anymore you basically just + + + align:start position:0% +analytically anymore you basically just +have to run a simulation for the most + + align:start position:0% +have to run a simulation for the most + + + align:start position:0% +have to run a simulation for the most +part the world is complicated and our + + align:start position:0% +part the world is complicated and our + + + align:start position:0% +part the world is complicated and our +models have to be run you here's a model + + align:start position:0% +models have to be run you here's a model + + + align:start position:0% +models have to be run you here's a model +of riverbed formation or these are + + align:start position:0% +of riverbed formation or these are + + + align:start position:0% +of riverbed formation or these are +snapshots of a model of galaxy collision + + align:start position:0% +snapshots of a model of galaxy collision + + + align:start position:0% +snapshots of a model of galaxy collision +or + + align:start position:0% +or + + + align:start position:0% +or +in climate modeling or aerodynamics so + + align:start position:0% +in climate modeling or aerodynamics so + + + align:start position:0% +in climate modeling or aerodynamics so +what a lot of you know basically what + + align:start position:0% +what a lot of you know basically what + + + align:start position:0% +what a lot of you know basically what +most modern science is is you write down + + align:start position:0% +most modern science is is you write down + + + align:start position:0% +most modern science is is you write down +descriptions of the causal processes + + align:start position:0% +descriptions of the causal processes + + + align:start position:0% +descriptions of the causal processes +something going on in the world and you + + align:start position:0% +something going on in the world and you + + + align:start position:0% +something going on in the world and you +study that through some combination of + + align:start position:0% +study that through some combination of + + + align:start position:0% +study that through some combination of +analysis and simulation to prety what + + align:start position:0% +analysis and simulation to prety what + + + align:start position:0% +analysis and simulation to prety what +would happen if you want to estimate + + align:start position:0% +would happen if you want to estimate + + + align:start position:0% +would happen if you want to estimate +parameters you try out some guesses of + + align:start position:0% +parameters you try out some guesses of + + + align:start position:0% +parameters you try out some guesses of +the parameters and you run this thing + + align:start position:0% +the parameters and you run this thing + + + align:start position:0% +the parameters and you run this thing +and you see if it's behavior looks like + + align:start position:0% +and you see if it's behavior looks like + + + align:start position:0% +and you see if it's behavior looks like +the data you observe if you are trying + + align:start position:0% +the data you observe if you are trying + + + align:start position:0% +the data you observe if you are trying +to decide between two different models + + align:start position:0% +to decide between two different models + + + align:start position:0% +to decide between two different models +you simulate each of them and you see + + align:start position:0% +you simulate each of them and you see + + + align:start position:0% +you simulate each of them and you see +which one looks more like the data you + + align:start position:0% +which one looks more like the data you + + + align:start position:0% +which one looks more like the data you +observe + + align:start position:0% +observe + + + align:start position:0% +observe +if you think there's something wrong + + align:start position:0% +if you think there's something wrong + + + align:start position:0% +if you think there's something wrong +with your model it doesn't quite look + + align:start position:0% +with your model it doesn't quite look + + + align:start position:0% +with your model it doesn't quite look +like the data you observe you think how + + align:start position:0% +like the data you observe you think how + + + align:start position:0% +like the data you observe you think how +can I change my model which basically if + + align:start position:0% +can I change my model which basically if + + + align:start position:0% +can I change my model which basically if +I run it it'll look more like the data I + + align:start position:0% +I run it it'll look more like the data I + + + align:start position:0% +I run it it'll look more like the data I +observe in some important way those are + + align:start position:0% +observe in some important way those are + + + align:start position:0% +observe in some important way those are +those activities of science those are + + align:start position:0% +those activities of science those are + + + align:start position:0% +those activities of science those are +what though those are in some form I'm + + align:start position:0% +what though those are in some form I'm + + + align:start position:0% +what though those are in some form I'm +arguing the activities of common sense + + align:start position:0% +arguing the activities of common sense + + + align:start position:0% +arguing the activities of common sense +explanation so when I'm talking about + + align:start position:0% +explanation so when I'm talking about + + + align:start position:0% +explanation so when I'm talking about +you know the child is scientist that's + + align:start position:0% +you know the child is scientist that's + + + align:start position:0% +you know the child is scientist that's +what I'm basically talking about it's + + align:start position:0% +what I'm basically talking about it's + + + align:start position:0% +what I'm basically talking about it's +some version of that and so that + + align:start position:0% +some version of that and so that + + + align:start position:0% +some version of that and so that +includes both using describing the + + align:start position:0% +includes both using describing the + + + align:start position:0% +includes both using describing the +causal processes with a program that you + + align:start position:0% +causal processes with a program that you + + + align:start position:0% +causal processes with a program that you +run or if you want to talk about + + align:start position:0% +run or if you want to talk about + + + align:start position:0% +run or if you want to talk about +learning right look the scientific + + align:start position:0% +learning right look the scientific + + + align:start position:0% +learning right look the scientific +analog is building one of these theories + + align:start position:0% +analog is building one of these theories + + + align:start position:0% +analog is building one of these theories +you don't build a what a theory of + + align:start position:0% +you don't build a what a theory of + + + align:start position:0% +you don't build a what a theory of +whether it's Newton's laws or Mendel's + + align:start position:0% +whether it's Newton's laws or Mendel's + + + align:start position:0% +whether it's Newton's laws or Mendel's +laws or any of these things by just + + align:start position:0% +laws or any of these things by just + + + align:start position:0% +laws or any of these things by just +finding patterns and data you do + + align:start position:0% +finding patterns and data you do + + + align:start position:0% +finding patterns and data you do +something like this this program thing + + align:start position:0% +something like this this program thing + + + align:start position:0% +something like this this program thing +but kind of recursively you mean you + + align:start position:0% +but kind of recursively you mean you + + + align:start position:0% +but kind of recursively you mean you +think you think of you having some kind + + align:start position:0% +think you think of you having some kind + + + align:start position:0% +think you think of you having some kind +of paradigm some program that generates + + align:start position:0% +of paradigm some program that generates + + + align:start position:0% +of paradigm some program that generates +programs and you use it to try to + + align:start position:0% +programs and you use it to try to + + + align:start position:0% +programs and you use it to try to +somehow search the space of programs to + + align:start position:0% +somehow search the space of programs to + + + align:start position:0% +somehow search the space of programs to +come up with a program that fits your + + align:start position:0% +come up with a program that fits your + + + align:start position:0% +come up with a program that fits your +data well okay so that's again kind of + + align:start position:0% +data well okay so that's again kind of + + + align:start position:0% +data well okay so that's again kind of +the big picture and now let's talk about + + align:start position:0% +the big picture and now let's talk about + + + align:start position:0% +the big picture and now let's talk about +how we can actually do something with + + align:start position:0% +how we can actually do something with + + + align:start position:0% +how we can actually do something with +this idea use these programs and all and + + align:start position:0% +this idea use these programs and all and + + + align:start position:0% +this idea use these programs and all and +you might be wondering okay maybe I + + align:start position:0% +you might be wondering okay maybe I + + + align:start position:0% +you might be wondering okay maybe I +maybe I understand well okay I want you + + align:start position:0% +maybe I understand well okay I want you + + + align:start position:0% +maybe I understand well okay I want you +to I'm realizing I didn't say the main + + align:start position:0% +to I'm realizing I didn't say the main + + + align:start position:0% +to I'm realizing I didn't say the main +thing I want you to understand the main + + align:start position:0% +thing I want you to understand the main + + + align:start position:0% +thing I want you to understand the main +thing I want you to get from this is how + + align:start position:0% +thing I want you to get from this is how + + + align:start position:0% +thing I want you to get from this is how +programs go beyond graphs right so none + + align:start position:0% +programs go beyond graphs right so none + + + align:start position:0% +programs go beyond graphs right so none +of these processes here can be nicely + + align:start position:0% +of these processes here can be nicely + + + align:start position:0% +of these processes here can be nicely +described with a graph right the way we + + align:start position:0% +described with a graph right the way we + + + align:start position:0% +described with a graph right the way we +have in the language of graphical models + + align:start position:0% +have in the language of graphical models + + + align:start position:0% +have in the language of graphical models +so that that the interesting causality I + + align:start position:0% +so that that the interesting causality I + + + align:start position:0% +so that that the interesting causality I +mean in some sense there's kind of a + + align:start position:0% +mean in some sense there's kind of a + + + align:start position:0% +mean in some sense there's kind of a +graph you can talk about the state of + + align:start position:0% +graph you can talk about the state of + + + align:start position:0% +graph you can talk about the state of +the world at time T and I'll show you + + align:start position:0% +the world at time T and I'll show you + + + align:start position:0% +the world at time T and I'll show you +graphs like this + + align:start position:0% +graphs like this + + + align:start position:0% +graphs like this +second the state of the world at time t + + align:start position:0% +second the state of the world at time t + + + align:start position:0% +second the state of the world at time t +plus one in an arrow forward in time but + + align:start position:0% +plus one in an arrow forward in time but + + + align:start position:0% +plus one in an arrow forward in time but +all the interesting stuff that science + + align:start position:0% +all the interesting stuff that science + + + align:start position:0% +all the interesting stuff that science +really gains power from are the much + + align:start position:0% +really gains power from are the much + + + align:start position:0% +really gains power from are the much +more fine grain structure captured in + + align:start position:0% +more fine grain structure captured in + + + align:start position:0% +more fine grain structure captured in +equations or functions that describe + + align:start position:0% +equations or functions that describe + + + align:start position:0% +equations or functions that describe +exactly how all this stuff works right + + align:start position:0% +exactly how all this stuff works right + + + align:start position:0% +exactly how all this stuff works right +and it needs languages like math or C++ + + align:start position:0% +and it needs languages like math or C++ + + + align:start position:0% +and it needs languages like math or C++ +or Lisp it needs a symbolic language of + + align:start position:0% +or Lisp it needs a symbolic language of + + + align:start position:0% +or Lisp it needs a symbolic language of +processes to really do justice to the + + align:start position:0% +processes to really do justice to the + + + align:start position:0% +processes to really do justice to the +second thing I want to get which will + + align:start position:0% +second thing I want to get which will + + + align:start position:0% +second thing I want to get which will +take a minute to get but let's put it + + align:start position:0% +take a minute to get but let's put it + + + align:start position:0% +take a minute to get but let's put it +out there is yes okay maybe you get the + + align:start position:0% +out there is yes okay maybe you get the + + + align:start position:0% +out there is yes okay maybe you get the +idea that programs can be used to + + align:start position:0% +idea that programs can be used to + + + align:start position:0% +idea that programs can be used to +describe causal processes in interesting + + align:start position:0% +describe causal processes in interesting + + + align:start position:0% +describe causal processes in interesting +ways but where does the probability part + + align:start position:0% +ways but where does the probability part + + + align:start position:0% +ways but where does the probability part +come in right so it's it the same thing + + align:start position:0% +come in right so it's it the same thing + + + align:start position:0% +come in right so it's it the same thing +is actually true in graphical models if + + align:start position:0% +is actually true in graphical models if + + + align:start position:0% +is actually true in graphical models if +you go in how many people have read + + align:start position:0% +you go in how many people have read + + + align:start position:0% +you go in how many people have read +judea pearls 2000 book called causality + + align:start position:0% +judea pearls 2000 book called causality + + + align:start position:0% +judea pearls 2000 book called causality +how people have read his 88th book or + + align:start position:0% +how people have read his 88th book or + + + align:start position:0% +how people have read his 88th book or +nobody's read anything but okay so what + + align:start position:0% +nobody's read anything but okay so what + + + align:start position:0% +nobody's read anything but okay so what +pearl is most famous for I mean when we + + align:start position:0% +pearl is most famous for I mean when we + + + align:start position:0% +pearl is most famous for I mean when we +say pearls famous for inventing Bayesian + + align:start position:0% +say pearls famous for inventing Bayesian + + + align:start position:0% +say pearls famous for inventing Bayesian +networks that's based on work he did in + + align:start position:0% +networks that's based on work he did in + + + align:start position:0% +networks that's based on work he did in +the 80s which in which yes they were all + + align:start position:0% +the 80s which in which yes they were all + + + align:start position:0% +the 80s which in which yes they were all +probability models but then he came to + + align:start position:0% +probability models but then he came to + + + align:start position:0% +probability models but then he came to +it what he calls and I would call to a + + align:start position:0% +it what he calls and I would call to a + + + align:start position:0% +it what he calls and I would call to a +deeper view in which it was really about + + align:start position:0% +deeper view in which it was really about + + + align:start position:0% +deeper view in which it was really about +basically deterministic calls relations + + align:start position:0% +basically deterministic calls relations + + + align:start position:0% +basically deterministic calls relations +basically it was a graphical language + + align:start position:0% +basically it was a graphical language + + + align:start position:0% +basically it was a graphical language +for four equations certain classes of + + align:start position:0% +for four equations certain classes of + + + align:start position:0% +for four equations certain classes of +equations like structural equations if + + align:start position:0% +equations like structural equations if + + + align:start position:0% +equations like structural equations if +you know about linear structural + + align:start position:0% +you know about linear structural + + + align:start position:0% +you know about linear structural +equations but sort of like nonlinear + + align:start position:0% +equations but sort of like nonlinear + + + align:start position:0% +equations but sort of like nonlinear +structural equations and then + + align:start position:0% +structural equations and then + + + align:start position:0% +structural equations and then +probabilities are these things you put + + align:start position:0% +probabilities are these things you put + + + align:start position:0% +probabilities are these things you put +on just on top of it to capture the + + align:start position:0% +on just on top of it to capture the + + + align:start position:0% +on just on top of it to capture the +things you don't know that you're + + align:start position:0% +things you don't know that you're + + + align:start position:0% +things you don't know that you're +uncertain about and I think he was he + + align:start position:0% +uncertain about and I think he was he + + + align:start position:0% +uncertain about and I think he was he +was getting at the fact that two + + align:start position:0% +was getting at the fact that two + + + align:start position:0% +was getting at the fact that two +scientists and also two people there's + + align:start position:0% +scientists and also two people there's + + + align:start position:0% +scientists and also two people there's +some very nice work by Laura Schultz and + + align:start position:0% +some very nice work by Laura Schultz and + + + align:start position:0% +some very nice work by Laura Schultz and +Jessica Somerville both of whom will be + + align:start position:0% +Jessica Somerville both of whom will be + + + align:start position:0% +Jessica Somerville both of whom will be +here next week actually on how + + align:start position:0% +here next week actually on how + + + align:start position:0% +here next week actually on how +children's concepts of causality are + + align:start position:0% +children's concepts of causality are + + + align:start position:0% +children's concepts of causality are +basically deterministic at the core and + + align:start position:0% +basically deterministic at the core and + + + align:start position:0% +basically deterministic at the core and +where the probabilities come in is on + + align:start position:0% +where the probabilities come in is on + + + align:start position:0% +where the probabilities come in is on +the things that we don't observe or the + + align:start position:0% +the things that we don't observe or the + + + align:start position:0% +the things that we don't observe or the +things we don't know the the uncertainty + + align:start position:0% +things we don't know the the uncertainty + + + align:start position:0% +things we don't know the the uncertainty +not it's not that the world is noisy + + align:start position:0% +not it's not that the world is noisy + + + align:start position:0% +not it's not that the world is noisy +it's that we believe at least except for + + align:start position:0% +it's that we believe at least except for + + + align:start position:0% +it's that we believe at least except for +quantum mechanics but our intuitive + + align:start position:0% +quantum mechanics but our intuitive + + + align:start position:0% +quantum mechanics but our intuitive +notions are that the world is basically + + align:start position:0% +notions are that the world is basically + + + align:start position:0% +notions are that the world is basically +deterministic but with a lot of stuff we + + align:start position:0% +deterministic but with a lot of stuff we + + + align:start position:0% +deterministic but with a lot of stuff we +don't know this was for example + + align:start position:0% +don't know this was for example + + + align:start position:0% +don't know this was for example +Laplace's view in philosophy of science + + align:start position:0% +Laplace's view in philosophy of science + + + align:start position:0% +Laplace's view in philosophy of science +and really until quantum mechanics it + + align:start position:0% +and really until quantum mechanics it + + + align:start position:0% +and really until quantum mechanics it +was broadly the enlightenment science + + align:start position:0% +was broadly the enlightenment science + + + align:start position:0% +was broadly the enlightenment science +view right that the world is full of all + + align:start position:0% +view right that the world is full of all + + + align:start position:0% +view right that the world is full of all +these complicated deterministic machines + + align:start position:0% +these complicated deterministic machines + + + align:start position:0% +these complicated deterministic machines +and where uncertainty comes from the + + align:start position:0% +and where uncertainty comes from the + + + align:start position:0% +and where uncertainty comes from the +things that we can't observe or that we + + align:start position:0% +things that we can't observe or that we + + + align:start position:0% +things that we can't observe or that we +can't measure finely enough or they're + + align:start position:0% +can't measure finely enough or they're + + + align:start position:0% +can't measure finely enough or they're +just in some form current unknowable + + align:start position:0% +just in some form current unknowable + + + align:start position:0% +just in some form current unknowable +unknown or unknowable to us + + align:start position:0% +unknown or unknowable to us + + + align:start position:0% +unknown or unknowable to us +does that make sense so so the I mean + + align:start position:0% +does that make sense so so the I mean + + + align:start position:0% +does that make sense so so the I mean +you'll see more of this in a second but + + align:start position:0% +you'll see more of this in a second but + + + align:start position:0% +you'll see more of this in a second but +where the probabilities are going to + + align:start position:0% +where the probabilities are going to + + + align:start position:0% +where the probabilities are going to +come from is basically if there are + + align:start position:0% +come from is basically if there are + + + align:start position:0% +come from is basically if there are +inputs to the program that we don't know + + align:start position:0% +inputs to the program that we don't know + + + align:start position:0% +inputs to the program that we don't know +or parameters we don't know then in + + align:start position:0% +or parameters we don't know then in + + + align:start position:0% +or parameters we don't know then in +order to simulate them are gonna have to + + align:start position:0% +order to simulate them are gonna have to + + + align:start position:0% +order to simulate them are gonna have to +put distributions on those and make some + + align:start position:0% +put distributions on those and make some + + + align:start position:0% +put distributions on those and make some +guesses and then see what happens for + + align:start position:0% +guesses and then see what happens for + + + align:start position:0% +guesses and then see what happens for +different guesses does that make sense + + align:start position:0% +different guesses does that make sense + + + align:start position:0% +different guesses does that make sense +okay um good so that's again that's most + + align:start position:0% +okay um good so that's again that's most + + + align:start position:0% +okay um good so that's again that's most +of the technical stuff I need to say and + + align:start position:0% +of the technical stuff I need to say and + + + align:start position:0% +of the technical stuff I need to say and +you'll you'll learn about how to how + + align:start position:0% +you'll you'll learn about how to how + + + align:start position:0% +you'll you'll learn about how to how +this works in much more concrete details + + align:start position:0% +this works in much more concrete details + + + align:start position:0% +this works in much more concrete details +if you go to the tutorial afterwards + + align:start position:0% +if you go to the tutorial afterwards + + + align:start position:0% +if you go to the tutorial afterwards +that Tomer is gonna run what you'll see + + align:start position:0% +that Tomer is gonna run what you'll see + + + align:start position:0% +that Tomer is gonna run what you'll see +there is this so here are just a few + + align:start position:0% +there is this so here are just a few + + + align:start position:0% +there is this so here are just a few +examples many of you hopefully already + + align:start position:0% +examples many of you hopefully already + + + align:start position:0% +examples many of you hopefully already +looked at these the web pages from this + + align:start position:0% +looked at these the web pages from this + + + align:start position:0% +looked at these the web pages from this +problem on storage thing and what you + + align:start position:0% +problem on storage thing and what you + + + align:start position:0% +problem on storage thing and what you +see here is basically each of these + + align:start position:0% +see here is basically each of these + + + align:start position:0% +see here is basically each of these +boxes is a probabilistic program model + + align:start position:0% +boxes is a probabilistic program model + + + align:start position:0% +boxes is a probabilistic program model +it most of it is a bunch of defined + + align:start position:0% +it most of it is a bunch of defined + + + align:start position:0% +it most of it is a bunch of defined +statements so if you look here you'll + + align:start position:0% +statements so if you look here you'll + + + align:start position:0% +statements so if you look here you'll +see these define statements those are + + align:start position:0% +see these define statements those are + + + align:start position:0% +see these define statements those are +just defining functions they name the + + align:start position:0% +just defining functions they name the + + + align:start position:0% +just defining functions they name the +function they take some inputs which + + align:start position:0% +function they take some inputs which + + + align:start position:0% +function they take some inputs which +call other functions and then they maybe + + align:start position:0% +call other functions and then they maybe + + + align:start position:0% +call other functions and then they maybe +do something they have some output that + + align:start position:0% +do something they have some output that + + + align:start position:0% +do something they have some output that +might be a an object it might itself be + + align:start position:0% +might be a an object it might itself be + + + align:start position:0% +might be a an object it might itself be +a function you know this is these can be + + align:start position:0% +a function you know this is these can be + + + align:start position:0% +a function you know this is these can be +functions that generate other functions + + align:start position:0% +functions that generate other functions + + + align:start position:0% +functions that generate other functions +and in some sense oh and and and where + + align:start position:0% +and in some sense oh and and and where + + + align:start position:0% +and in some sense oh and and and where +the probabilities come in is that + + align:start position:0% +the probabilities come in is that + + + align:start position:0% +the probabilities come in is that +sometimes these functions call random + + align:start position:0% +sometimes these functions call random + + + align:start position:0% +sometimes these functions call random +number generators basically if you look + + align:start position:0% +number generators basically if you look + + + align:start position:0% +number generators basically if you look +carefully you'll see things like D relay + + align:start position:0% +carefully you'll see things like D relay + + + align:start position:0% +carefully you'll see things like D relay +or uniform draw or Gaussian or flip + + align:start position:0% +or uniform draw or Gaussian or flip + + + align:start position:0% +or uniform draw or Gaussian or flip +right those are primitive random + + align:start position:0% +right those are primitive random + + + align:start position:0% +right those are primitive random +functions that flip a coin or roll a die + + align:start position:0% +functions that flip a coin or roll a die + + + align:start position:0% +functions that flip a coin or roll a die +or draw from a Gaussian and those + + align:start position:0% +or draw from a Gaussian and those + + + align:start position:0% +or draw from a Gaussian and those +capture things that that are currently + + align:start position:0% +capture things that that are currently + + + align:start position:0% +capture things that that are currently +unknown right in a very important sense + + align:start position:0% +unknown right in a very important sense + + + align:start position:0% +unknown right in a very important sense +the particular language church that + + align:start position:0% +the particular language church that + + + align:start position:0% +the particular language church that +you're gonna learn here with it's sort + + align:start position:0% +you're gonna learn here with it's sort + + + align:start position:0% +you're gonna learn here with it's sort +of stochastic lists basically just + + align:start position:0% +of stochastic lists basically just + + + align:start position:0% +of stochastic lists basically just +functions that call other functions and + + align:start position:0% +functions that call other functions and + + + align:start position:0% +functions that call other functions and +maybe add in some randomness to that is + + align:start position:0% +maybe add in some randomness to that is + + + align:start position:0% +maybe add in some randomness to that is +very much analogous to the directed + + align:start position:0% +very much analogous to the directed + + + align:start position:0% +very much analogous to the directed +graph of a Bayesian network in a + + align:start position:0% +graph of a Bayesian network in a + + + align:start position:0% +graph of a Bayesian network in a +Bayesian network you have nodes and + + align:start position:0% +Bayesian network you have nodes and + + + align:start position:0% +Bayesian network you have nodes and +arrows and the parents of a node the + + align:start position:0% +arrows and the parents of a node the + + + align:start position:0% +arrows and the parents of a node the +ones that send arrows to it are the + + align:start position:0% +ones that send arrows to it are the + + + align:start position:0% +ones that send arrows to it are the +basically the minimal set of variables + + align:start position:0% +basically the minimal set of variables + + + align:start position:0% +basically the minimal set of variables +that if you were going to sample from + + align:start position:0% +that if you were going to sample from + + + align:start position:0% +that if you were going to sample from +this model you'd have to sample first in + + align:start position:0% +this model you'd have to sample first in + + + align:start position:0% +this model you'd have to sample first in +order to then sample the child variable + + align:start position:0% +order to then sample the child variable + + + align:start position:0% +order to then sample the child variable +cuz it's those are the key things it + + align:start position:0% +cuz it's those are the key things it + + + align:start position:0% +cuz it's those are the key things it +depends on and you can have a + + align:start position:0% +depends on and you can have a + + + align:start position:0% +depends on and you can have a +multi-layered Bayesian network that if + + align:start position:0% +multi-layered Bayesian network that if + + + align:start position:0% +multi-layered Bayesian network that if +you were going to sample from it is just + + align:start position:0% +you were going to sample from it is just + + + align:start position:0% +you were going to sample from it is just +you start at the top and you sort of go + + align:start position:0% +you start at the top and you sort of go + + + align:start position:0% +you start at the top and you sort of go +down that's exactly the same thing you + + align:start position:0% +down that's exactly the same thing you + + + align:start position:0% +down that's exactly the same thing you +have in these probabilistic programs + + align:start position:0% +have in these probabilistic programs + + + align:start position:0% +have in these probabilistic programs +where the defined statements are + + align:start position:0% +where the defined statements are + + + align:start position:0% +where the defined statements are +basically defining a function and said + + align:start position:0% +basically defining a function and said + + + align:start position:0% +basically defining a function and said +the func that the functions are the + + align:start position:0% +the func that the functions are the + + + align:start position:0% +the func that the functions are the +nodes + + align:start position:0% +nodes + + + align:start position:0% +nodes +and the other functions that they call + + align:start position:0% +and the other functions that they call + + + align:start position:0% +and the other functions that they call +as part of the statement are the things + + align:start position:0% +as part of the statement are the things + + + align:start position:0% +as part of the statement are the things +that are the nodes that send arrows + + align:start position:0% +that are the nodes that send arrows + + + align:start position:0% +that are the nodes that send arrows +there but the key is as you can imagine + + align:start position:0% +there but the key is as you can imagine + + + align:start position:0% +there but the key is as you can imagine +if you've ever I mean all of you written + + align:start position:0% +if you've ever I mean all of you written + + + align:start position:0% +if you've ever I mean all of you written +computer programs is that it's only very + + align:start position:0% +computer programs is that it's only very + + + align:start position:0% +computer programs is that it's only very +simple programs look like directed + + align:start position:0% +simple programs look like directed + + + align:start position:0% +simple programs look like directed +acyclic graphs and that's what a + + align:start position:0% +acyclic graphs and that's what a + + + align:start position:0% +acyclic graphs and that's what a +Bayesian network is it's very easy and + + align:start position:0% +Bayesian network is it's very easy and + + + align:start position:0% +Bayesian network is it's very easy and +often necessary to write a program to + + align:start position:0% +often necessary to write a program to + + + align:start position:0% +often necessary to write a program to +really capture something causally + + align:start position:0% +really capture something causally + + + align:start position:0% +really capture something causally +interesting in the world where it's not + + align:start position:0% +interesting in the world where it's not + + + align:start position:0% +interesting in the world where it's not +a directed a solute there's all sorts of + + align:start position:0% +a directed a solute there's all sorts of + + + align:start position:0% +a directed a solute there's all sorts of +cycles there's recursion one thing that + + align:start position:0% +cycles there's recursion one thing that + + + align:start position:0% +cycles there's recursion one thing that +a function can do is make a whole other + + align:start position:0% +a function can do is make a whole other + + + align:start position:0% +a function can do is make a whole other +graph right or often it's it might be + + align:start position:0% +graph right or often it's it might be + + + align:start position:0% +graph right or often it's it might be +directed in a cyclic but all the + + align:start position:0% +directed in a cyclic but all the + + + align:start position:0% +directed in a cyclic but all the +interesting stuff is kind of going on + + align:start position:0% +interesting stuff is kind of going on + + + align:start position:0% +interesting stuff is kind of going on +inside what happens when you evaluate + + align:start position:0% +inside what happens when you evaluate + + + align:start position:0% +inside what happens when you evaluate +one function so if you were to draw it + + align:start position:0% +one function so if you were to draw it + + + align:start position:0% +one function so if you were to draw it +as a graph it might look like you could + + align:start position:0% +as a graph it might look like you could + + + align:start position:0% +as a graph it might look like you could +draw a directed acyclic graph but all + + align:start position:0% +draw a directed acyclic graph but all + + + align:start position:0% +draw a directed acyclic graph but all +the interesting stuff will be going on + + align:start position:0% +the interesting stuff will be going on + + + align:start position:0% +the interesting stuff will be going on +inside one ERA or what one node or one + + align:start position:0% +inside one ERA or what one node or one + + + align:start position:0% +inside one ERA or what one node or one +arrow so let me get more specific about + + align:start position:0% +arrow so let me get more specific about + + + align:start position:0% +arrow so let me get more specific about +the particular kind of programs that + + align:start position:0% +the particular kind of programs that + + + align:start position:0% +the particular kind of programs that +we're going to be talking about in the + + align:start position:0% +we're going to be talking about in the + + + align:start position:0% +we're going to be talking about in the +language in a probabilistic programming + + align:start position:0% +language in a probabilistic programming + + + align:start position:0% +language in a probabilistic programming +language like church or in general in + + align:start position:0% +language like church or in general in + + + align:start position:0% +language like church or in general in +this view of the mind we're interested + + align:start position:0% +this view of the mind we're interested + + + align:start position:0% +this view of the mind we're interested +in being able to build really any I mean + + align:start position:0% +in being able to build really any I mean + + + align:start position:0% +in being able to build really any I mean +kind of thing again there's there's lots + + align:start position:0% +kind of thing again there's there's lots + + + align:start position:0% +kind of thing again there's there's lots +of big dreams here like I was saying + + align:start position:0% +of big dreams here like I was saying + + + align:start position:0% +of big dreams here like I was saying +before we had I felt like we had to give + + align:start position:0% +before we had I felt like we had to give + + + align:start position:0% +before we had I felt like we had to give +up on some dreams but we've replaced it + + align:start position:0% +up on some dreams but we've replaced it + + + align:start position:0% +up on some dreams but we've replaced it +with even grander ones like + + align:start position:0% +with even grander ones like + + + align:start position:0% +with even grander ones like +probabilistic modeling engines that can + + align:start position:0% +probabilistic modeling engines that can + + + align:start position:0% +probabilistic modeling engines that can +do any computable model but in the + + align:start position:0% +do any computable model but in the + + + align:start position:0% +do any computable model but in the +spirit of trying to scale up from + + align:start position:0% +spirit of trying to scale up from + + + align:start position:0% +spirit of trying to scale up from +something that we can get traction on + + align:start position:0% +something that we can get traction on + + + align:start position:0% +something that we can get traction on +right what I've been focusing on in a + + align:start position:0% +right what I've been focusing on in a + + + align:start position:0% +right what I've been focusing on in a +lot of my work recently and what we've + + align:start position:0% +lot of my work recently and what we've + + + align:start position:0% +lot of my work recently and what we've +been doing part of as part of the center + + align:start position:0% +been doing part of as part of the center + + + align:start position:0% +been doing part of as part of the center +our particular probabilistic programs + + align:start position:0% +our particular probabilistic programs + + + align:start position:0% +our particular probabilistic programs +that we think can capture this very + + align:start position:0% +that we think can capture this very + + + align:start position:0% +that we think can capture this very +early core of common sense intuitive + + align:start position:0% +early core of common sense intuitive + + + align:start position:0% +early core of common sense intuitive +physics and intuitive psychology in + + align:start position:0% +physics and intuitive psychology in + + + align:start position:0% +physics and intuitive psychology in +young kids it's what I called and I + + align:start position:0% +young kids it's what I called and I + + + align:start position:0% +young kids it's what I called and I +remember I mentioned this in the first + + align:start position:0% +remember I mentioned this in the first + + + align:start position:0% +remember I mentioned this in the first +lecture this game engine in your head + + align:start position:0% +lecture this game engine in your head + + + align:start position:0% +lecture this game engine in your head +right so it's programs for graphics + + align:start position:0% +right so it's programs for graphics + + + align:start position:0% +right so it's programs for graphics +engines physics engines planning engines + + align:start position:0% +engines physics engines planning engines + + + align:start position:0% +engines physics engines planning engines +the basic kinds of things you might use + + align:start position:0% +the basic kinds of things you might use + + + align:start position:0% +the basic kinds of things you might use +to build one of these immersive video + + align:start position:0% +to build one of these immersive video + + + align:start position:0% +to build one of these immersive video +games and we think if you wrap those + + align:start position:0% +games and we think if you wrap those + + + align:start position:0% +games and we think if you wrap those +inside this framework for probabilistic + + align:start position:0% +inside this framework for probabilistic + + + align:start position:0% +inside this framework for probabilistic +inference then that's a powerful way to + + align:start position:0% +inference then that's a powerful way to + + + align:start position:0% +inference then that's a powerful way to +do the kind of common-sense scene + + align:start position:0% +do the kind of common-sense scene + + + align:start position:0% +do the kind of common-sense scene +understanding whether it in these adult + + align:start position:0% +understanding whether it in these adult + + + align:start position:0% +understanding whether it in these adult +versions Ori or in the young kid + + align:start position:0% +versions Ori or in the young kid + + + align:start position:0% +versions Ori or in the young kid +versions now there's that this I mean to + + align:start position:0% +versions now there's that this I mean to + + + align:start position:0% +versions now there's that this I mean to +specify this probablistic programs view + + align:start position:0% +specify this probablistic programs view + + + align:start position:0% +specify this probablistic programs view +just like with Bayesian networks or + + align:start position:0% +just like with Bayesian networks or + + + align:start position:0% +just like with Bayesian networks or +these graphical models we wanted general + + align:start position:0% +these graphical models we wanted general + + + align:start position:0% +these graphical models we wanted general +purpose + + align:start position:0% +purpose + + + align:start position:0% +purpose +tools for representing interesting + + align:start position:0% +tools for representing interesting + + + align:start position:0% +tools for representing interesting +things in the world and for computing + + align:start position:0% +things in the world and for computing + + + align:start position:0% +things in the world and for computing +the inferences that were that we want + + align:start position:0% +the inferences that were that we want + + + align:start position:0% +the inferences that were that we want +which again which means basically + + align:start position:0% +which again which means basically + + + align:start position:0% +which again which means basically +observing say just like you observe the + + align:start position:0% +observing say just like you observe the + + + align:start position:0% +observing say just like you observe the +some of the symptoms and you want to + + align:start position:0% +some of the symptoms and you want to + + + align:start position:0% +some of the symptoms and you want to +compute the likely diseases that best + + align:start position:0% +compute the likely diseases that best + + + align:start position:0% +compute the likely diseases that best +explain the observed symptoms here we + + align:start position:0% +explain the observed symptoms here we + + + align:start position:0% +explain the observed symptoms here we +talk about observing the outputs of some + + align:start position:0% +talk about observing the outputs of some + + + align:start position:0% +talk about observing the outputs of some +of these programs these like the image + + align:start position:0% +of these programs these like the image + + + align:start position:0% +of these programs these like the image +that's the output of a graphics program + + align:start position:0% +that's the output of a graphics program + + + align:start position:0% +that's the output of a graphics program +and we want to work backwards and make a + + align:start position:0% +and we want to work backwards and make a + + + align:start position:0% +and we want to work backwards and make a +guess at the world state the input to + + align:start position:0% +guess at the world state the input to + + + align:start position:0% +guess at the world state the input to +the graphics engine that's most likely + + align:start position:0% +the graphics engine that's most likely + + + align:start position:0% +the graphics engine that's most likely +to have produced the image that's the + + align:start position:0% +to have produced the image that's the + + + align:start position:0% +to have produced the image that's the +analog of getting diseases from symptoms + + align:start position:0% +analog of getting diseases from symptoms + + + align:start position:0% +analog of getting diseases from symptoms +or that's again it's that's our + + align:start position:0% +or that's again it's that's our + + + align:start position:0% +or that's again it's that's our +explanation right there and there are + + align:start position:0% +explanation right there and there are + + + align:start position:0% +explanation right there and there are +lots of different algorithms for doing + + align:start position:0% +lots of different algorithms for doing + + + align:start position:0% +lots of different algorithms for doing +this I'm not going to say too much about + + align:start position:0% +this I'm not going to say too much about + + + align:start position:0% +this I'm not going to say too much about +them + + align:start position:0% +them + + + align:start position:0% +them +Tomer we'll say a little bit more in the + + align:start position:0% +Tomer we'll say a little bit more in the + + + align:start position:0% +Tomer we'll say a little bit more in the +afternoon the main thing I will do is I + + align:start position:0% +afternoon the main thing I will do is I + + + align:start position:0% +afternoon the main thing I will do is I +will say that that the main + + align:start position:0% +will say that that the main + + + align:start position:0% +will say that that the main +general-purpose algorithms for infants + + align:start position:0% +general-purpose algorithms for infants + + + align:start position:0% +general-purpose algorithms for infants +and probably sick programming language + + align:start position:0% +and probably sick programming language + + + align:start position:0% +and probably sick programming language +are in the category of slow and slower + + align:start position:0% +are in the category of slow and slower + + + align:start position:0% +are in the category of slow and slower +and really really slow and you know + + align:start position:0% +and really really slow and you know + + + align:start position:0% +and really really slow and you know +there's no this is one of the many ways + + align:start position:0% +there's no this is one of the many ways + + + align:start position:0% +there's no this is one of the many ways +in which there's no magic or no free + + align:start position:0% +in which there's no magic or no free + + + align:start position:0% +in which there's no magic or no free +lunch if you across all of AI in + + align:start position:0% +lunch if you across all of AI in + + + align:start position:0% +lunch if you across all of AI in +cognitive science when you build very + + align:start position:0% +cognitive science when you build very + + + align:start position:0% +cognitive science when you build very +powerful representations doing inference + + align:start position:0% +powerful representations doing inference + + + align:start position:0% +powerful representations doing inference +with them becomes very hard it's part of + + align:start position:0% +with them becomes very hard it's part of + + + align:start position:0% +with them becomes very hard it's part of +why people often like things like neural + + align:start position:0% +why people often like things like neural + + + align:start position:0% +why people often like things like neural +networks they're much weaker + + align:start position:0% +networks they're much weaker + + + align:start position:0% +networks they're much weaker +representations but inference can be + + align:start position:0% +representations but inference can be + + + align:start position:0% +representations but inference can be +much faster and at the moment the only + + align:start position:0% +much faster and at the moment the only + + + align:start position:0% +much faster and at the moment the only +totally general-purpose algorithms for + + align:start position:0% +totally general-purpose algorithms for + + + align:start position:0% +totally general-purpose algorithms for +doing inference with policy programs are + + align:start position:0% +doing inference with policy programs are + + + align:start position:0% +doing inference with policy programs are +slow but first of all they're getting + + align:start position:0% +slow but first of all they're getting + + + align:start position:0% +slow but first of all they're getting +faster people are coming up with and I + + align:start position:0% +faster people are coming up with and I + + + align:start position:0% +faster people are coming up with and I +can talk about this offline where that's + + align:start position:0% +can talk about this offline where that's + + + align:start position:0% +can talk about this offline where that's +going but also and this is where what + + align:start position:0% +going but also and this is where what + + + align:start position:0% +going but also and this is where what +I'll talk about in a more sharper way in + + align:start position:0% +I'll talk about in a more sharper way in + + + align:start position:0% +I'll talk about in a more sharper way in +a second um there are particular classes + + align:start position:0% +a second um there are particular classes + + + align:start position:0% +a second um there are particular classes +of problems big programs in particular + + align:start position:0% +of problems big programs in particular + + + align:start position:0% +of problems big programs in particular +the ones in the game engine in your head + + align:start position:0% +the ones in the game engine in your head + + + align:start position:0% +the ones in the game engine in your head +like for vision is inverse graphics and + + align:start position:0% +like for vision is inverse graphics and + + + align:start position:0% +like for vision is inverse graphics and +maybe some things about physics and + + align:start position:0% +maybe some things about physics and + + + align:start position:0% +maybe some things about physics and +psychology too but that's there's a lot + + align:start position:0% +psychology too but that's there's a lot + + + align:start position:0% +psychology too but that's there's a lot +that's that's just this I mean again I'm + + align:start position:0% +that's that's just this I mean again I'm + + + align:start position:0% +that's that's just this I mean again I'm +just thinking of the stuff of like + + align:start position:0% +just thinking of the stuff of like + + + align:start position:0% +just thinking of the stuff of like +what's going on with it when a kid is + + align:start position:0% +what's going on with it when a kid is + + + align:start position:0% +what's going on with it when a kid is +playing with some objects around them + + align:start position:0% +playing with some objects around them + + + align:start position:0% +playing with some objects around them +and thinking about what other people + + align:start position:0% +and thinking about what other people + + + align:start position:0% +and thinking about what other people +might think about those things it's just + + align:start position:0% +might think about those things it's just + + + align:start position:0% +might think about those things it's just +that setting where we think that you can + + align:start position:0% +that setting where we think that you can + + + align:start position:0% +that setting where we think that you can +build sort of in some sense special + + align:start position:0% +build sort of in some sense special + + + align:start position:0% +build sort of in some sense special +purpose I mean they're still pretty + + align:start position:0% +purpose I mean they're still pretty + + + align:start position:0% +purpose I mean they're still pretty +general but inference algorithms for + + align:start position:0% +general but inference algorithms for + + + align:start position:0% +general but inference algorithms for +doing inference in public programs for + + align:start position:0% +doing inference in public programs for + + + align:start position:0% +doing inference in public programs for +doing getting the causes from the + + align:start position:0% +doing getting the causes from the + + + align:start position:0% +doing getting the causes from the +effects that are much much faster than + + align:start position:0% +effects that are much much faster than + + + align:start position:0% +effects that are much much faster than +things that could work on just arbitrary + + align:start position:0% +things that could work on just arbitrary + + + align:start position:0% +things that could work on just arbitrary +probabilistic programs + + align:start position:0% +probabilistic programs + + + align:start position:0% +probabilistic programs +and that actually often look a lot like + + align:start position:0% +and that actually often look a lot like + + + align:start position:0% +and that actually often look a lot like +neural networks and in particular we can + + align:start position:0% +neural networks and in particular we can + + + align:start position:0% +neural networks and in particular we can +directly use say for example deep + + align:start position:0% +directly use say for example deep + + + align:start position:0% +directly use say for example deep +convolutional neural networks to build + + align:start position:0% +convolutional neural networks to build + + + align:start position:0% +convolutional neural networks to build +these recognition programs or you know + + align:start position:0% +these recognition programs or you know + + + align:start position:0% +these recognition programs or you know +especially basically inference programs + + align:start position:0% +especially basically inference programs + + + align:start position:0% +especially basically inference programs +that work by a pattern recognition in + + align:start position:0% +that work by a pattern recognition in + + + align:start position:0% +that work by a pattern recognition in +for example an inverse graphics approach + + align:start position:0% +for example an inverse graphics approach + + + align:start position:0% +for example an inverse graphics approach +division so that's what I'll show you + + align:start position:0% +division so that's what I'll show you + + + align:start position:0% +division so that's what I'll show you +basically now I'm gonna start off by + + align:start position:0% +basically now I'm gonna start off by + + + align:start position:0% +basically now I'm gonna start off by +just working through a couple of these + + align:start position:0% +just working through a couple of these + + + align:start position:0% +just working through a couple of these +arrows I'm gonna first talk about this + + align:start position:0% +arrows I'm gonna first talk about this + + + align:start position:0% +arrows I'm gonna first talk about this +sort of approach we've done to tackle + + align:start position:0% +sort of approach we've done to tackle + + + align:start position:0% +sort of approach we've done to tackle +both vision is inverse graphics and some + + align:start position:0% +both vision is inverse graphics and some + + + align:start position:0% +both vision is inverse graphics and some +intuitive physics on on the scene + + align:start position:0% +intuitive physics on on the scene + + + align:start position:0% +intuitive physics on on the scene +recovered and then say a little bit + + align:start position:0% +recovered and then say a little bit + + + align:start position:0% +recovered and then say a little bit +about the intuitive psychology side um + + align:start position:0% +about the intuitive psychology side um + + + align:start position:0% +about the intuitive psychology side um +the here's an example of the kind of + + align:start position:0% +the here's an example of the kind of + + + align:start position:0% +the here's an example of the kind of +specific domain we've studied it's like + + align:start position:0% +specific domain we've studied it's like + + + align:start position:0% +specific domain we've studied it's like +our Atari setting it's a kind of video + + align:start position:0% +our Atari setting it's a kind of video + + + align:start position:0% +our Atari setting it's a kind of video +game inspired by the real game Jenga + + align:start position:0% +game inspired by the real game Jenga + + + align:start position:0% +game inspired by the real game Jenga +Jenga is this cool game you played with + + align:start position:0% +Jenga is this cool game you played with + + + align:start position:0% +Jenga is this cool game you played with +wooden blocks you start off with a + + align:start position:0% +wooden blocks you start off with a + + + align:start position:0% +wooden blocks you start off with a +nicely very very very nicely stacked up + + align:start position:0% +nicely very very very nicely stacked up + + + align:start position:0% +nicely very very very nicely stacked up +thing and you take turns removing the + + align:start position:0% +thing and you take turns removing the + + + align:start position:0% +thing and you take turns removing the +blocks and the player who removes the + + align:start position:0% +blocks and the player who removes the + + + align:start position:0% +blocks and the player who removes the +block that makes the whole thing fall + + align:start position:0% +block that makes the whole thing fall + + + align:start position:0% +block that makes the whole thing fall +over as the one who loses and it really + + align:start position:0% +over as the one who loses and it really + + + align:start position:0% +over as the one who loses and it really +exercises this part of your brain that + + align:start position:0% +exercises this part of your brain that + + + align:start position:0% +exercises this part of your brain that +we've been studying here which is an + + align:start position:0% +we've been studying here which is an + + + align:start position:0% +we've been studying here which is an +ability to reason about stability and + + align:start position:0% +ability to reason about stability and + + + align:start position:0% +ability to reason about stability and +support which I very briefly went over + + align:start position:0% +support which I very briefly went over + + + align:start position:0% +support which I very briefly went over +this but this is something that it's one + + align:start position:0% +this but this is something that it's one + + + align:start position:0% +this but this is something that it's one +of the classic case studies of infant + + align:start position:0% +of the classic case studies of infant + + + align:start position:0% +of the classic case studies of infant +object knowledge looking at how + + align:start position:0% +object knowledge looking at how + + + align:start position:0% +object knowledge looking at how +basically these concepts develop in some + + align:start position:0% +basically these concepts develop in some + + + align:start position:0% +basically these concepts develop in some +really interesting ways over the first + + align:start position:0% +really interesting ways over the first + + + align:start position:0% +really interesting ways over the first +year of life though what we're doing + + align:start position:0% +year of life though what we're doing + + + align:start position:0% +year of life though what we're doing +here is building models and testing them + + align:start position:0% +here is building models and testing them + + + align:start position:0% +here is building models and testing them +primarily with adults it is part of what + + align:start position:0% +primarily with adults it is part of what + + + align:start position:0% +primarily with adults it is part of what +we're trying to do in our brains minds + + align:start position:0% +we're trying to do in our brains minds + + + align:start position:0% +we're trying to do in our brains minds +and machines research program here is + + align:start position:0% +and machines research program here is + + + align:start position:0% +and machines research program here is +which collaboration with Liz and others + + align:start position:0% +which collaboration with Liz and others + + + align:start position:0% +which collaboration with Liz and others +to actually test these ideas in + + align:start position:0% +to actually test these ideas in + + + align:start position:0% +to actually test these ideas in +experiments with infants but what I'll + + align:start position:0% +experiments with infants but what I'll + + + align:start position:0% +experiments with infants but what I'll +show you is just kind of think of it as + + align:start position:0% +show you is just kind of think of it as + + + align:start position:0% +show you is just kind of think of it as +like infant inspired adult intuitive + + align:start position:0% +like infant inspired adult intuitive + + + align:start position:0% +like infant inspired adult intuitive +physics that where we build and test the + + align:start position:0% +physics that where we build and test the + + + align:start position:0% +physics that where we build and test the +models in an easier way and then we're + + align:start position:0% +models in an easier way and then we're + + + align:start position:0% +models in an easier way and then we're +taking it down to kids going forward so + + align:start position:0% +taking it down to kids going forward so + + + align:start position:0% +taking it down to kids going forward so +the kind of experiment we can do with + + align:start position:0% +the kind of experiment we can do with + + + align:start position:0% +the kind of experiment we can do with +adults is show them these configurations + + align:start position:0% +adults is show them these configurations + + + align:start position:0% +adults is show them these configurations +of blocks and say for example how stable + + align:start position:0% +of blocks and say for example how stable + + + align:start position:0% +of blocks and say for example how stable +under gravity are is one of these + + align:start position:0% +under gravity are is one of these + + + align:start position:0% +under gravity are is one of these +guitars or configurations so you know + + align:start position:0% +guitars or configurations so you know + + + align:start position:0% +guitars or configurations so you know +like everything else you can make a + + align:start position:0% +like everything else you can make a + + + align:start position:0% +like everything else you can make a +judgment on a scale of 0 to 10 or 1 to 7 + + align:start position:0% +judgment on a scale of 0 to 10 or 1 to 7 + + + align:start position:0% +judgment on a scale of 0 to 10 or 1 to 7 +and probably most people would agree + + align:start position:0% +and probably most people would agree + + + align:start position:0% +and probably most people would agree +that the ones in the upper left are + + align:start position:0% +that the ones in the upper left are + + + align:start position:0% +that the ones in the upper left are +relatively stable meaning if you just + + align:start position:0% +relatively stable meaning if you just + + + align:start position:0% +relatively stable meaning if you just +sort of run gravity on it it's not gonna + + align:start position:0% +sort of run gravity on it it's not gonna + + + align:start position:0% +sort of run gravity on it it's not gonna +fall over whereas the ones in the lower + + align:start position:0% +fall over whereas the ones in the lower + + + align:start position:0% +fall over whereas the ones in the lower +right are much more likely to fall under + + align:start position:0% +right are much more likely to fall under + + + align:start position:0% +right are much more likely to fall under +gravity fair enough that's what people + + align:start position:0% +gravity fair enough that's what people + + + align:start position:0% +gravity fair enough that's what people +say ok + + align:start position:0% +say ok + + + align:start position:0% +say ok +so that's the kind of thing we'd like to + + align:start position:0% +so that's the kind of thing we'd like to + + + align:start position:0% +so that's the kind of thing we'd like to +be able to explain as well as many other + + align:start position:0% +be able to explain as well as many other + + + align:start position:0% +be able to explain as well as many other +judgments you could make about this + + align:start position:0% +judgments you could make about this + + + align:start position:0% +judgments you could make about this +simple but not that simple world of + + align:start position:0% +simple but not that simple world of + + + align:start position:0% +simple but not that simple world of +objects and again you can see how in + + align:start position:0% +objects and again you can see how in + + + align:start position:0% +objects and again you can see how in +principle this could very nice the + + align:start position:0% +principle this could very nice the + + + align:start position:0% +principle this could very nice the +interface with what Denis was talking + + align:start position:0% +interface with what Denis was talking + + + align:start position:0% +interface with what Denis was talking +about he talked about their ambition to + + align:start position:0% +about he talked about their ambition to + + + align:start position:0% +about he talked about their ambition to +do the Shirley task which was this + + align:start position:0% +do the Shirley task which was this + + + align:start position:0% +do the Shirley task which was this +ability to basically take have a system + + align:start position:0% +ability to basically take have a system + + + align:start position:0% +ability to basically take have a system +that can take in instructions in + + align:start position:0% +that can take in instructions in + + + align:start position:0% +that can take in instructions in +language and manipulate objects in + + align:start position:0% +language and manipulate objects in + + + align:start position:0% +language and manipulate objects in +blocks world they are very far from that + + align:start position:0% +blocks world they are very far from that + + + align:start position:0% +blocks world they are very far from that +everybody's really far from having a + + align:start position:0% +everybody's really far from having a + + + align:start position:0% +everybody's really far from having a +general-purpose system that can do that + + align:start position:0% +general-purpose system that can do that + + + align:start position:0% +general-purpose system that can do that +in any way like a human does but we + + align:start position:0% +in any way like a human does but we + + + align:start position:0% +in any way like a human does but we +think we're building some of the common + + align:start position:0% +think we're building some of the common + + + align:start position:0% +think we're building some of the common +sense knowledge about the physical world + + align:start position:0% +sense knowledge about the physical world + + + align:start position:0% +sense knowledge about the physical world +that would be necessary to get something + + align:start position:0% +that would be necessary to get something + + + align:start position:0% +that would be necessary to get something +like that to work or to explain how kids + + align:start position:0% +like that to work or to explain how kids + + + align:start position:0% +like that to work or to explain how kids +play with blocks play with each other + + align:start position:0% +play with blocks play with each other + + + align:start position:0% +play with blocks play with each other +talk to each other while they're playing + + align:start position:0% +talk to each other while they're playing + + + align:start position:0% +talk to each other while they're playing +with blocks and so on so the first step + + align:start position:0% +with blocks and so on so the first step + + + align:start position:0% +with blocks and so on so the first step +is the vision part right in this picture + + align:start position:0% +is the vision part right in this picture + + + align:start position:0% +is the vision part right in this picture +here it's that blue graphics arrow + + align:start position:0% +here it's that blue graphics arrow + + + align:start position:0% +here it's that blue graphics arrow +here's another way into it we take we + + align:start position:0% +here's another way into it we take we + + + align:start position:0% +here's another way into it we take we +want to be able to take a 2d image and + + align:start position:0% +want to be able to take a 2d image and + + + align:start position:0% +want to be able to take a 2d image and +work backwards to the world state the + + align:start position:0% +work backwards to the world state the + + + align:start position:0% +work backwards to the world state the +kind of world egg that can support + + align:start position:0% +kind of world egg that can support + + + align:start position:0% +kind of world egg that can support +physical reasoning again when I remember + + align:start position:0% +physical reasoning again when I remember + + + align:start position:0% +physical reasoning again when I remember +these buzzwords call explaining the mind + + align:start position:0% +these buzzwords call explaining the mind + + + align:start position:0% +these buzzwords call explaining the mind +with the generative models that are + + align:start position:0% +with the generative models that are + + + align:start position:0% +with the generative models that are +causal and compositional we want a + + align:start position:0% +causal and compositional we want a + + + align:start position:0% +causal and compositional we want a +description of the world which supports + + align:start position:0% +description of the world which supports + + + align:start position:0% +description of the world which supports +causal reasoning of the sort that + + align:start position:0% +causal reasoning of the sort that + + + align:start position:0% +causal reasoning of the sort that +physics is doing like forces interacting + + align:start position:0% +physics is doing like forces interacting + + + align:start position:0% +physics is doing like forces interacting +with each other so it's got to have + + align:start position:0% +with each other so it's got to have + + + align:start position:0% +with each other so it's got to have +things that can exert force and can + + align:start position:0% +things that can exert force and can + + + align:start position:0% +things that can exert force and can +suffer forces got to have mass in some + + align:start position:0% +suffer forces got to have mass in some + + + align:start position:0% +suffer forces got to have mass in some +form it's got to be compositional + + align:start position:0% +form it's got to be compositional + + + align:start position:0% +form it's got to be compositional +because you got to be able to pick up a + + align:start position:0% +because you got to be able to pick up a + + + align:start position:0% +because you got to be able to pick up a +block and take it away or you know if I + + align:start position:0% +block and take it away or you know if I + + + align:start position:0% +block and take it away or you know if I +have these blocks over here and these + + align:start position:0% +have these blocks over here and these + + + align:start position:0% +have these blocks over here and these +blocks over here and I want to put these + + align:start position:0% +blocks over here and I want to put these + + + align:start position:0% +blocks over here and I want to put these +ones on top of there the world state has + + align:start position:0% +ones on top of there the world state has + + + align:start position:0% +ones on top of there the world state has +to be able to support any number of + + align:start position:0% +to be able to support any number of + + + align:start position:0% +to be able to support any number of +objects in any configuration and to + + align:start position:0% +objects in any configuration and to + + + align:start position:0% +objects in any configuration and to +literally compose a representation of a + + align:start position:0% +literally compose a representation of a + + + align:start position:0% +literally compose a representation of a +world of objects that are composed + + align:start position:0% +world of objects that are composed + + + align:start position:0% +world of objects that are composed +together to make a bigger things so + + align:start position:0% +together to make a bigger things so + + + align:start position:0% +together to make a bigger things so +really the only way we know how to do + + align:start position:0% +really the only way we know how to do + + + align:start position:0% +really the only way we know how to do +that is something like what sometimes in + + align:start position:0% +that is something like what sometimes in + + + align:start position:0% +that is something like what sometimes in +engineering called a CAD model or + + align:start position:0% +engineering called a CAD model or + + + align:start position:0% +engineering called a CAD model or +computer-aided design but it's basically + + align:start position:0% +computer-aided design but it's basically + + + align:start position:0% +computer-aided design but it's basically +a representation of three-dimensional + + align:start position:0% +a representation of three-dimensional + + + align:start position:0% +a representation of three-dimensional +objects often with something like a MASH + + align:start position:0% +objects often with something like a MASH + + + align:start position:0% +objects often with something like a MASH +or a grid of key points with their + + align:start position:0% +or a grid of key points with their + + + align:start position:0% +or a grid of key points with their +masses and Springs for stiffness + + align:start position:0% +masses and Springs for stiffness + + + align:start position:0% +masses and Springs for stiffness +something like that here my only picture + + align:start position:0% +something like that here my only picture + + + align:start position:0% +something like that here my only picture +of the world state looks an awful lot + + align:start position:0% +of the world state looks an awful lot + + + align:start position:0% +of the world state looks an awful lot +like the image only it's in black and + + align:start position:0% +like the image only it's in black and + + + align:start position:0% +like the image only it's in black and +white as head of color but the + + align:start position:0% +white as head of color but the + + + align:start position:0% +white as head of color but the +difference is that the thing on the + + align:start position:0% +difference is that the thing on the + + + align:start position:0% +difference is that the thing on the +bottom is actually an image whereas the + + align:start position:0% +bottom is actually an image whereas the + + + align:start position:0% +bottom is actually an image whereas the +thing on the top is just a 2d projection + + align:start position:0% +thing on the top is just a 2d projection + + + align:start position:0% +thing on the top is just a 2d projection +of a 3d model I'll show you that one + + align:start position:0% +of a 3d model I'll show you that one + + + align:start position:0% +of a 3d model I'll show you that one +I'll show you here's a few others so + + align:start position:0% +I'll show you here's a few others so + + + align:start position:0% +I'll show you here's a few others so +I'll go back and forth between these + + align:start position:0% +I'll go back and forth between these + + + align:start position:0% +I'll go back and forth between these +notice how it kind of looks like the + + align:start position:0% +notice how it kind of looks like the + + + align:start position:0% +notice how it kind of looks like the +blocks are moving around so what's + + align:start position:0% +blocks are moving around so what's + + + align:start position:0% +blocks are moving around so what's +actually going on is these are Sam + + align:start position:0% +actually going on is these are Sam + + + align:start position:0% +actually going on is these are Sam +from the Bayesian posterior in an + + align:start position:0% +from the Bayesian posterior in an + + + align:start position:0% +from the Bayesian posterior in an +inverse graphic system we put a prior on + + align:start position:0% +inverse graphic system we put a prior on + + + align:start position:0% +inverse graphic system we put a prior on +world stage which is basically a prior + + align:start position:0% +world stage which is basically a prior + + + align:start position:0% +world stage which is basically a prior +on what we think the world is made out + + align:start position:0% +on what we think the world is made out + + + align:start position:0% +on what we think the world is made out +of we think there's these Jenga blocks + + align:start position:0% +of we think there's these Jenga blocks + + + align:start position:0% +of we think there's these Jenga blocks +basically um and then the likelihood + + align:start position:0% +basically um and then the likelihood + + + align:start position:0% +basically um and then the likelihood +which is that that forward model it's + + align:start position:0% +which is that that forward model it's + + + align:start position:0% +which is that that forward model it's +the it's the probability of seeing a + + align:start position:0% +the it's the probability of seeing a + + + align:start position:0% +the it's the probability of seeing a +particular 2d image given a 3d + + align:start position:0% +particular 2d image given a 3d + + + align:start position:0% +particular 2d image given a 3d +configuration of blocks and going back + + align:start position:0% +configuration of blocks and going back + + + align:start position:0% +configuration of blocks and going back +to the thing you said it's basically + + align:start position:0% +to the thing you said it's basically + + + align:start position:0% +to the thing you said it's basically +deterministic with a little bit of noise + + align:start position:0% +deterministic with a little bit of noise + + + align:start position:0% +deterministic with a little bit of noise +it's deterministic it just follows the + + align:start position:0% +it's deterministic it just follows the + + + align:start position:0% +it's deterministic it just follows the +rules of OpenGL graphics basically says + + align:start position:0% +rules of OpenGL graphics basically says + + + align:start position:0% +rules of OpenGL graphics basically says +you know objects have surfaces they're + + align:start position:0% +you know objects have surfaces they're + + + align:start position:0% +you know objects have surfaces they're +not transparent you can't see through + + align:start position:0% +not transparent you can't see through + + + align:start position:0% +not transparent you can't see through +them that's an extra complication if you + + align:start position:0% +them that's an extra complication if you + + + align:start position:0% +them that's an extra complication if you +wanted to have that and and basically + + align:start position:0% +wanted to have that and and basically + + + align:start position:0% +wanted to have that and and basically +the image is formed by taking the + + align:start position:0% +the image is formed by taking the + + + align:start position:0% +the image is formed by taking the +closest surface of the closest object + + align:start position:0% +closest surface of the closest object + + + align:start position:0% +closest surface of the closest object +and bouncing a ray of light off of it + + align:start position:0% +and bouncing a ray of light off of it + + + align:start position:0% +and bouncing a ray of light off of it +which really just means taking its color + + align:start position:0% +which really just means taking its color + + + align:start position:0% +which really just means taking its color +and scaling it by intensity it's a very + + align:start position:0% +and scaling it by intensity it's a very + + + align:start position:0% +and scaling it by intensity it's a very +simple shadow model so that's the causal + + align:start position:0% +simple shadow model so that's the causal + + + align:start position:0% +simple shadow model so that's the causal +model and then we can add a little bit + + align:start position:0% +model and then we can add a little bit + + + align:start position:0% +model and then we can add a little bit +of uncertainty like for example maybe we + + align:start position:0% +of uncertainty like for example maybe we + + + align:start position:0% +of uncertainty like for example maybe we +can't you know there's a little bit of + + align:start position:0% +can't you know there's a little bit of + + + align:start position:0% +can't you know there's a little bit of +noise in the sensor data so you can you + + align:start position:0% +noise in the sensor data so you can you + + + align:start position:0% +noise in the sensor data so you can you +know you can be uncertain about exactly + + align:start position:0% +know you can be uncertain about exactly + + + align:start position:0% +know you can be uncertain about exactly +the low-level image features and then + + align:start position:0% +the low-level image features and then + + + align:start position:0% +the low-level image features and then +when you run one of these promising + + align:start position:0% +when you run one of these promising + + + align:start position:0% +when you run one of these promising +programs in Reverse to make a guess of + + align:start position:0% +programs in Reverse to make a guess of + + + align:start position:0% +programs in Reverse to make a guess of +what configuration of locks is most + + align:start position:0% +what configuration of locks is most + + + align:start position:0% +what configuration of locks is most +likely to have produced that image + + align:start position:0% +likely to have produced that image + + + align:start position:0% +likely to have produced that image +there's a little bit of posterior + + align:start position:0% +there's a little bit of posterior + + + align:start position:0% +there's a little bit of posterior +uncertainty that inherits from the fact + + align:start position:0% +uncertainty that inherits from the fact + + + align:start position:0% +uncertainty that inherits from the fact +that you just you know yeah or you can't + + align:start position:0% +that you just you know yeah or you can't + + + align:start position:0% +that you just you know yeah or you can't +exactly localize those objects in the + + align:start position:0% +exactly localize those objects in the + + + align:start position:0% +exactly localize those objects in the +world so again what you see here are + + align:start position:0% +world so again what you see here are + + + align:start position:0% +world so again what you see here are +three or four samples from the posterior + + align:start position:0% +three or four samples from the posterior + + + align:start position:0% +three or four samples from the posterior +the distribution over best guesses of + + align:start position:0% +the distribution over best guesses of + + + align:start position:0% +the distribution over best guesses of +the world state of 3d objects that were + + align:start position:0% +the world state of 3d objects that were + + + align:start position:0% +the world state of 3d objects that were +most likely to have rendered into that + + align:start position:0% +most likely to have rendered into that + + + align:start position:0% +most likely to have rendered into that +2d image and any one of those is now an + + align:start position:0% +2d image and any one of those is now an + + + align:start position:0% +2d image and any one of those is now an +actionable representation for physical + + align:start position:0% +actionable representation for physical + + + align:start position:0% +actionable representation for physical +manipulation or reasoning okay and how + + align:start position:0% +manipulation or reasoning okay and how + + + align:start position:0% +manipulation or reasoning okay and how +we actually compute that again I'm not + + align:start position:0% +we actually compute that again I'm not + + + align:start position:0% +we actually compute that again I'm not +going to go into right now I'll go into + + align:start position:0% +going to go into right now I'll go into + + + align:start position:0% +going to go into right now I'll go into +something something like it in a minute + + align:start position:0% +something something like it in a minute + + + align:start position:0% +something something like it in a minute +but at least in its most basic form it + + align:start position:0% +but at least in its most basic form it + + + align:start position:0% +but at least in its most basic form it +involves some rather unfortunately slow + + align:start position:0% +involves some rather unfortunately slow + + + align:start position:0% +involves some rather unfortunately slow +random search process through the space + + align:start position:0% +random search process through the space + + + align:start position:0% +random search process through the space +of blocks models okay here's another + + align:start position:0% +of blocks models okay here's another + + + align:start position:0% +of blocks models okay here's another +example this is another configuration + + align:start position:0% +example this is another configuration + + + align:start position:0% +example this is another configuration +there or another image and here is a few + + align:start position:0% +there or another image and here is a few + + + align:start position:0% +there or another image and here is a few +samples again from the posterior and + + align:start position:0% +samples again from the posterior and + + + align:start position:0% +samples again from the posterior and +hopefully when you see these things + + align:start position:0% +hopefully when you see these things + + + align:start position:0% +hopefully when you see these things +moving around whether it's this one or + + align:start position:0% +moving around whether it's this one or + + + align:start position:0% +moving around whether it's this one or +the one before you see them move a + + align:start position:0% +the one before you see them move a + + + align:start position:0% +the one before you see them move a +little bit but most of them look very + + align:start position:0% +little bit but most of them look very + + + align:start position:0% +little bit but most of them look very +similar right like you'd be hard-pressed + + align:start position:0% +similar right like you'd be hard-pressed + + + align:start position:0% +similar right like you'd be hard-pressed +to tell the difference if you looked + + align:start position:0% +to tell the difference if you looked + + + align:start position:0% +to tell the difference if you looked +away for a second between any one of + + align:start position:0% +away for a second between any one of + + + align:start position:0% +away for a second between any one of +those like what + + align:start position:0% +those like what + + + align:start position:0% +those like what +one of my are you actually seeing and + + align:start position:0% +one of my are you actually seeing and + + + align:start position:0% +one of my are you actually seeing and +that's exactly the point the the + + align:start position:0% +that's exactly the point the the + + + align:start position:0% +that's exactly the point the the +uncertainty you see there is meant to + + align:start position:0% +uncertainty you see there is meant to + + + align:start position:0% +uncertainty you see there is meant to +capture basically the uncertainty you + + align:start position:0% +capture basically the uncertainty you + + + align:start position:0% +capture basically the uncertainty you +have which in a single glance at an + + align:start position:0% +have which in a single glance at an + + + align:start position:0% +have which in a single glance at an +image like that + + align:start position:0% +image like that + + + align:start position:0% +image like that +you can't perfectly tell where the + + align:start position:0% +you can't perfectly tell where the + + + align:start position:0% +you can't perfectly tell where the +blocks are so basically any one of these + + align:start position:0% +blocks are so basically any one of these + + + align:start position:0% +blocks are so basically any one of these +can fit any one of these configurations + + align:start position:0% +can fit any one of these configurations + + + align:start position:0% +can fit any one of these configurations +up here is about equally good and we + + align:start position:0% +up here is about equally good and we + + + align:start position:0% +up here is about equally good and we +think your intuitive physics your sort + + align:start position:0% +think your intuitive physics your sort + + + align:start position:0% +think your intuitive physics your sort +of common sense core intuitive physics + + align:start position:0% +of common sense core intuitive physics + + + align:start position:0% +of common sense core intuitive physics +that even babies have is operating over + + align:start position:0% +that even babies have is operating over + + + align:start position:0% +that even babies have is operating over +one or a few samples like that now in + + align:start position:0% +one or a few samples like that now in + + + align:start position:0% +one or a few samples like that now in +separate work that is not really I don't + + align:start position:0% +separate work that is not really I don't + + + align:start position:0% +separate work that is not really I don't +think of it as really about common sense + + align:start position:0% +think of it as really about common sense + + + align:start position:0% +think of it as really about common sense +but it's one of the things we've been + + align:start position:0% +but it's one of the things we've been + + + align:start position:0% +but it's one of the things we've been +doing in our group and in CBMM where + + align:start position:0% +doing in our group and in CBMM where + + + align:start position:0% +doing in our group and in CBMM where +these ideas best make contact with the + + align:start position:0% +these ideas best make contact with the + + + align:start position:0% +these ideas best make contact with the +rest of what people are doing here and + + align:start position:0% +rest of what people are doing here and + + + align:start position:0% +rest of what people are doing here and +where we can really test you know + + align:start position:0% +where we can really test you know + + + align:start position:0% +where we can really test you know +interesting neural hypotheses + + align:start position:0% +interesting neural hypotheses + + + align:start position:0% +interesting neural hypotheses +potentially and understand the interplay + + align:start position:0% +potentially and understand the interplay + + + align:start position:0% +potentially and understand the interplay +between these generative models for + + align:start position:0% +between these generative models for + + + align:start position:0% +between these generative models for +explanation and the more sort of neural + + align:start position:0% +explanation and the more sort of neural + + + align:start position:0% +explanation and the more sort of neural +network type models for pattern + + align:start position:0% +network type models for pattern + + + align:start position:0% +network type models for pattern +recognition we've been we've been really + + align:start position:0% +recognition we've been we've been really + + + align:start position:0% +recognition we've been we've been really +pushing on this idea of vision is + + align:start position:0% +pushing on this idea of vision is + + + align:start position:0% +pushing on this idea of vision is +inverse graphics so I'll tell you a + + align:start position:0% +inverse graphics so I'll tell you a + + + align:start position:0% +inverse graphics so I'll tell you a +little bit about that because it's it's + + align:start position:0% +little bit about that because it's it's + + + align:start position:0% +little bit about that because it's it's +quite interesting for CMMI but I want to + + align:start position:0% +quite interesting for CMMI but I want to + + + align:start position:0% +quite interesting for CMMI but I want to +make sure to save I'll only do this for + + align:start position:0% +make sure to save I'll only do this for + + + align:start position:0% +make sure to save I'll only do this for +about five minutes and then go back to + + align:start position:0% +about five minutes and then go back to + + + align:start position:0% +about five minutes and then go back to +the how this gets used for more the + + align:start position:0% +the how this gets used for more the + + + align:start position:0% +the how this gets used for more the +intuitive physics and planning stuff so + + align:start position:0% +intuitive physics and planning stuff so + + + align:start position:0% +intuitive physics and planning stuff so +this is this is example an example from + + align:start position:0% +this is this is example an example from + + + align:start position:0% +this is this is example an example from +a paper by Tejas Kulkarni who's one of + + align:start position:0% +a paper by Tejas Kulkarni who's one of + + + align:start position:0% +a paper by Tejas Kulkarni who's one of +our grad students and it's joint work + + align:start position:0% +our grad students and it's joint work + + + align:start position:0% +our grad students and it's joint work +with a few other really smart people + + align:start position:0% +with a few other really smart people + + + align:start position:0% +with a few other really smart people +such as Vikash man Singha who's a + + align:start position:0% +such as Vikash man Singha who's a + + + align:start position:0% +such as Vikash man Singha who's a +research scientist at MIT and pushed me + + align:start position:0% +research scientist at MIT and pushed me + + + align:start position:0% +research scientist at MIT and pushed me +coley who's at Microsoft Research and it + + align:start position:0% +coley who's at Microsoft Research and it + + + align:start position:0% +coley who's at Microsoft Research and it +was a computer vision paper pure + + align:start position:0% +was a computer vision paper pure + + + align:start position:0% +was a computer vision paper pure +computer vision paper from the summer + + align:start position:0% +computer vision paper from the summer + + + align:start position:0% +computer vision paper from the summer +where he was developing a general or it + + align:start position:0% +where he was developing a general or it + + + align:start position:0% +where he was developing a general or it +was a specific kind of problems like + + align:start position:0% +was a specific kind of problems like + + + align:start position:0% +was a specific kind of problems like +programming language but a general one + + align:start position:0% +programming language but a general one + + + align:start position:0% +programming language but a general one +for doing this kind of vision as inverse + + align:start position:0% +for doing this kind of vision as inverse + + + align:start position:0% +for doing this kind of vision as inverse +graphics where you would you could give + + align:start position:0% +graphics where you would you could give + + + align:start position:0% +graphics where you would you could give +a number of different models here I'll + + align:start position:0% +a number of different models here I'll + + + align:start position:0% +a number of different models here I'll +show you one for faces and other one for + + align:start position:0% +show you one for faces and other one for + + + align:start position:0% +show you one for faces and other one for +bodies and other one for generic objects + + align:start position:0% +bodies and other one for generic objects + + + align:start position:0% +bodies and other one for generic objects +but basically you you can pretty easily + + align:start position:0% +but basically you you can pretty easily + + + align:start position:0% +but basically you you can pretty easily +specify a graphics model that when you + + align:start position:0% +specify a graphics model that when you + + + align:start position:0% +specify a graphics model that when you +run it in the forward Direction + + align:start position:0% +run it in the forward Direction + + + align:start position:0% +run it in the forward Direction +generates random images of objects in a + + align:start position:0% +generates random images of objects in a + + + align:start position:0% +generates random images of objects in a +certain class and then you can run it in + + align:start position:0% +certain class and then you can run it in + + + align:start position:0% +certain class and then you can run it in +the reverse direction to do scene + + align:start position:0% +the reverse direction to do scene + + + align:start position:0% +the reverse direction to do scene +parsing to go from the image to the + + align:start position:0% +parsing to go from the image to the + + + align:start position:0% +parsing to go from the image to the +observe or to the underlying scene so + + align:start position:0% +observe or to the underlying scene so + + + align:start position:0% +observe or to the underlying scene so +here's an example of this in phases + + align:start position:0% +here's an example of this in phases + + + align:start position:0% +here's an example of this in phases +where the graphics model it's it's it's + + align:start position:0% +where the graphics model it's it's it's + + + align:start position:0% +where the graphics model it's it's it's +really very directly based on work that + + align:start position:0% +really very directly based on work that + + + align:start position:0% +really very directly based on work that +Thomas Vetter who was a former a student + + align:start position:0% +Thomas Vetter who was a former a student + + + align:start position:0% +Thomas Vetter who was a former a student +or a postdoc of Tommy's actually so kind + + align:start position:0% +or a postdoc of Tommy's actually so kind + + + align:start position:0% +or a postdoc of Tommy's actually so kind +of a early ancestor of CBMM built and + + align:start position:0% +of a early ancestor of CBMM built and + + + align:start position:0% +of a early ancestor of CBMM built and +his group in Basel Switzerland + + align:start position:0% +his group in Basel Switzerland + + + align:start position:0% +his group in Basel Switzerland +where it's it's a simple but still + + align:start position:0% +where it's it's a simple but still + + + align:start position:0% +where it's it's a simple but still +pretty nice graphics model for making + + align:start position:0% +pretty nice graphics model for making + + + align:start position:0% +pretty nice graphics model for making +face images there's a model of the shape + + align:start position:0% +face images there's a model of the shape + + + align:start position:0% +face images there's a model of the shape +of the face which again it's like a CAD + + align:start position:0% +of the face which again it's like a CAD + + + align:start position:0% +of the face which again it's like a CAD +model it's a it's a mesh surface + + align:start position:0% +model it's a it's a mesh surface + + + align:start position:0% +model it's a it's a mesh surface +description pretty fine grained + + align:start position:0% +description pretty fine grained + + + align:start position:0% +description pretty fine grained +structure of the 2d but surface of a + + align:start position:0% +structure of the 2d but surface of a + + + align:start position:0% +structure of the 2d but surface of a +face in 3d and there's about 400 + + align:start position:0% +face in 3d and there's about 400 + + + align:start position:0% +face in 3d and there's about 400 +dimensions to characterize the possible + + align:start position:0% +dimensions to characterize the possible + + + align:start position:0% +dimensions to characterize the possible +shapes of faces and there's another four + + align:start position:0% +shapes of faces and there's another four + + + align:start position:0% +shapes of faces and there's another four +in two dimensions to characterize the + + align:start position:0% +in two dimensions to characterize the + + + align:start position:0% +in two dimensions to characterize the +texture which is like the skin the beard + + align:start position:0% +texture which is like the skin the beard + + + align:start position:0% +texture which is like the skin the beard +the eyes you know the color and surface + + align:start position:0% +the eyes you know the color and surface + + + align:start position:0% +the eyes you know the color and surface +properties that get mapped on top of the + + align:start position:0% +properties that get mapped on top of the + + + align:start position:0% +properties that get mapped on top of the +mesh and then there's a little bit more + + align:start position:0% +mesh and then there's a little bit more + + + align:start position:0% +mesh and then there's a little bit more +graphic stuff which is generic not + + align:start position:0% +graphic stuff which is generic not + + + align:start position:0% +graphic stuff which is generic not +specific to faces that stuff is all + + align:start position:0% +specific to faces that stuff is all + + + align:start position:0% +specific to faces that stuff is all +specific to faces but then there's a + + align:start position:0% +specific to faces but then there's a + + + align:start position:0% +specific to faces but then there's a +simple lighting model so you basically + + align:start position:0% +simple lighting model so you basically + + + align:start position:0% +simple lighting model so you basically +have a point light source somewhere out + + align:start position:0% +have a point light source somewhere out + + + align:start position:0% +have a point light source somewhere out +there and you shine the light on the + + align:start position:0% +there and you shine the light on the + + + align:start position:0% +there and you shine the light on the +face it can produce shadows of course + + align:start position:0% +face it can produce shadows of course + + + align:start position:0% +face it can produce shadows of course +but not very complicated ones and then + + align:start position:0% +but not very complicated ones and then + + + align:start position:0% +but not very complicated ones and then +there's a viewpoint camera thing so you + + align:start position:0% +there's a viewpoint camera thing so you + + + align:start position:0% +there's a viewpoint camera thing so you +put the light source somewhere and you + + align:start position:0% +put the light source somewhere and you + + + align:start position:0% +put the light source somewhere and you +put a camera somewhere specifying the + + align:start position:0% +put a camera somewhere specifying the + + + align:start position:0% +put a camera somewhere specifying the +viewpoint and the combination of these + + align:start position:0% +viewpoint and the combination of these + + + align:start position:0% +viewpoint and the combination of these +shape texture lighting and camera give + + align:start position:0% +shape texture lighting and camera give + + + align:start position:0% +shape texture lighting and camera give +you a complete graphic specification it + + align:start position:0% +you a complete graphic specification it + + + align:start position:0% +you a complete graphic specification it +produces an image of a particular face + + align:start position:0% +produces an image of a particular face + + + align:start position:0% +produces an image of a particular face +lit from a particular direction and + + align:start position:0% +lit from a particular direction and + + + align:start position:0% +lit from a particular direction and +viewed from some particular viewpoint + + align:start position:0% +viewed from some particular viewpoint + + + align:start position:0% +viewed from some particular viewpoint +and distance and what you see on the + + align:start position:0% +and distance and what you see on the + + + align:start position:0% +and distance and what you see on the +right are random samples from this + + align:start position:0% +right are random samples from this + + + align:start position:0% +right are random samples from this +probabilistic program this generative + + align:start position:0% +probabilistic program this generative + + + align:start position:0% +probabilistic program this generative +model so you can just write this program + + align:start position:0% +model so you can just write this program + + + align:start position:0% +model so you can just write this program +and press go go-go-go-go and every time + + align:start position:0% +and press go go-go-go-go and every time + + + align:start position:0% +and press go go-go-go-go and every time +you run it you get a new face viewed + + align:start position:0% +you run it you get a new face viewed + + + align:start position:0% +you run it you get a new face viewed +from a new direction and lighting + + align:start position:0% +from a new direction and lighting + + + align:start position:0% +from a new direction and lighting +condition so that's the prior now what + + align:start position:0% +condition so that's the prior now what + + + align:start position:0% +condition so that's the prior now what +about inference well the idea of vision + + align:start position:0% +about inference well the idea of vision + + + align:start position:0% +about inference well the idea of vision +is inverse graphics is to say take a + + align:start position:0% +is inverse graphics is to say take a + + + align:start position:0% +is inverse graphics is to say take a +real image of a face like that one and + + align:start position:0% +real image of a face like that one and + + + align:start position:0% +real image of a face like that one and +see if you can produce from your + + align:start position:0% +see if you can produce from your + + + align:start position:0% +see if you can produce from your +graphics model something that looks like + + align:start position:0% +graphics model something that looks like + + + align:start position:0% +graphics model something that looks like +that so for example here in the lower + + align:start position:0% +that so for example here in the lower + + + align:start position:0% +that so for example here in the lower +left is an example of a face that was + + align:start position:0% +left is an example of a face that was + + + align:start position:0% +left is an example of a face that was +produced from the graphics model but + + align:start position:0% +produced from the graphics model but + + + align:start position:0% +produced from the graphics model but +hopefully most agree looks kind of like + + align:start position:0% +hopefully most agree looks kind of like + + + align:start position:0% +hopefully most agree looks kind of like +that not maybe not exactly the same but + + align:start position:0% +that not maybe not exactly the same but + + + align:start position:0% +that not maybe not exactly the same but +kind of enough and in building this + + align:start position:0% +kind of enough and in building this + + + align:start position:0% +kind of enough and in building this +system this pic this system by the way + + align:start position:0% +system this pic this system by the way + + + align:start position:0% +system this pic this system by the way +is called picture that's the first word + + align:start position:0% +is called picture that's the first word + + + align:start position:0% +is called picture that's the first word +of the paper title to the Kulkarni a + + align:start position:0% +of the paper title to the Kulkarni a + + + align:start position:0% +of the paper title to the Kulkarni a +tall paper um there were a few neat + + align:start position:0% +tall paper um there were a few neat + + + align:start position:0% +tall paper um there were a few neat +things that had to be done one of the + + align:start position:0% +things that had to be done one of the + + + align:start position:0% +things that had to be done one of the +things that had to be done was to come + + align:start position:0% +things that had to be done was to come + + + align:start position:0% +things that had to be done was to come +up with various ways to compare to to + + align:start position:0% +up with various ways to compare to to + + + align:start position:0% +up with various ways to compare to to +say what does it mean for the output of + + align:start position:0% +say what does it mean for the output of + + + align:start position:0% +say what does it mean for the output of +the graphics engine to look like the + + align:start position:0% +the graphics engine to look like the + + + align:start position:0% +the graphics engine to look like the +image in the case of faces actually + + align:start position:0% +image in the case of faces actually + + + align:start position:0% +image in the case of faces actually +matching at pixels is not completely + + align:start position:0% +matching at pixels is not completely + + + align:start position:0% +matching at pixels is not completely +crazy but for many most vision problems + + align:start position:0% +crazy but for many most vision problems + + + align:start position:0% +crazy but for many most vision problems +you're it's going to be unrealistic and + + align:start position:0% +you're it's going to be unrealistic and + + + align:start position:0% +you're it's going to be unrealistic and +not unnecessary to build a graphics + + align:start position:0% +not unnecessary to build a graphics + + + align:start position:0% +not unnecessary to build a graphics +engine that's pixel level realistic and + + align:start position:0% +engine that's pixel level realistic and + + + align:start position:0% +engine that's pixel level realistic and +so you might frig + + align:start position:0% +so you might frig + + + align:start position:0% +so you might frig +people want to have something where the + + align:start position:0% +people want to have something where the + + + align:start position:0% +people want to have something where the +graphics engine hypothesis is matched to + + align:start position:0% +graphics engine hypothesis is matched to + + + align:start position:0% +graphics engine hypothesis is matched to +the image with something like some kind + + align:start position:0% +the image with something like some kind + + + align:start position:0% +the image with something like some kind +of features like could be convolutional + + align:start position:0% +of features like could be convolutional + + + align:start position:0% +of features like could be convolutional +neural network features that's one way + + align:start position:0% +neural network features that's one way + + + align:start position:0% +neural network features that's one way +to use for example neural networks to + + align:start position:0% +to use for example neural networks to + + + align:start position:0% +to use for example neural networks to +make something like this work well and + + align:start position:0% +make something like this work well and + + + align:start position:0% +make something like this work well and +John John just showed me a paper by some + + align:start position:0% +John John just showed me a paper by some + + + align:start position:0% +John John just showed me a paper by some +other folks from Darmstadt which is + + align:start position:0% +other folks from Darmstadt which is + + + align:start position:0% +other folks from Darmstadt which is +doing what looks like a very interesting + + align:start position:0% +doing what looks like a very interesting + + + align:start position:0% +doing what looks like a very interesting +similar kind of thing + + align:start position:0% +similar kind of thing + + + align:start position:0% +similar kind of thing +let me let me show what what inference + + align:start position:0% +let me let me show what what inference + + + align:start position:0% +let me let me show what what inference +looks like in this model and then say + + align:start position:0% +looks like in this model and then say + + + align:start position:0% +looks like in this model and then say +what I think is an even more interesting + + align:start position:0% +what I think is an even more interesting + + + align:start position:0% +what I think is an even more interesting +way to use convolutional nets from + + align:start position:0% +way to use convolutional nets from + + + align:start position:0% +way to use convolutional nets from +another recent paper we've been looking + + align:start position:0% +another recent paper we've been looking + + + align:start position:0% +another recent paper we've been looking +at so here's um you just watch this this + + align:start position:0% +at so here's um you just watch this this + + + align:start position:0% +at so here's um you just watch this this +is one observed face and what you're + + align:start position:0% +is one observed face and what you're + + + align:start position:0% +is one observed face and what you're +seeing over here is just a trace of the + + align:start position:0% +seeing over here is just a trace of the + + + align:start position:0% +seeing over here is just a trace of the +system kind of do searching through the + + align:start position:0% +system kind of do searching through the + + + align:start position:0% +system kind of do searching through the +space of traces of the graphics program + + align:start position:0% +space of traces of the graphics program + + + align:start position:0% +space of traces of the graphics program +like basically trying out random faces + + align:start position:0% +like basically trying out random faces + + + align:start position:0% +like basically trying out random faces +that might look like that face there + + align:start position:0% +that might look like that face there + + + align:start position:0% +that might look like that face there +it's using a kind of MCMC inference very + + align:start position:0% +it's using a kind of MCMC inference very + + + align:start position:0% +it's using a kind of MCMC inference very +similar to what you're going to see from + + align:start position:0% +similar to what you're going to see from + + + align:start position:0% +similar to what you're going to see from +Tomer in the tutorial um it basically + + align:start position:0% +Tomer in the tutorial um it basically + + + align:start position:0% +Tomer in the tutorial um it basically +starts off with a random face and takes + + align:start position:0% +starts off with a random face and takes + + + align:start position:0% +starts off with a random face and takes +a bunch of small random steps that are + + align:start position:0% +a bunch of small random steps that are + + + align:start position:0% +a bunch of small random steps that are +biased towards getting making the image + + align:start position:0% +biased towards getting making the image + + + align:start position:0% +biased towards getting making the image +look more and more like the actual + + align:start position:0% +look more and more like the actual + + + align:start position:0% +look more and more like the actual +observed image right and at the end you + + align:start position:0% +observed image right and at the end you + + + align:start position:0% +observed image right and at the end you +have something which looks almost + + align:start position:0% +have something which looks almost + + + align:start position:0% +have something which looks almost +identical to the observed face right but + + align:start position:0% +identical to the observed face right but + + + align:start position:0% +identical to the observed face right but +key right oh is that though the observed + + align:start position:0% +key right oh is that though the observed + + + align:start position:0% +key right oh is that though the observed +face is literally just a 2d image the + + align:start position:0% +face is literally just a 2d image the + + + align:start position:0% +face is literally just a 2d image the +thing you're seeing on the right is a + + align:start position:0% +thing you're seeing on the right is a + + + align:start position:0% +thing you're seeing on the right is a +projection of a 3d model of a face and + + align:start position:0% +projection of a 3d model of a face and + + + align:start position:0% +projection of a 3d model of a face and +it's one that supports a lot of causal + + align:start position:0% +it's one that supports a lot of causal + + + align:start position:0% +it's one that supports a lot of causal +action right so here just to show you on + + align:start position:0% +action right so here just to show you on + + + align:start position:0% +action right so here just to show you on +a more interesting sort of higher + + align:start position:0% +a more interesting sort of higher + + + align:start position:0% +a more interesting sort of higher +resolution set of face images the ones + + align:start position:0% +resolution set of face images the ones + + + align:start position:0% +resolution set of face images the ones +on the left are observed images and then + + align:start position:0% +on the left are observed images and then + + + align:start position:0% +on the left are observed images and then +we do this we fit this model and then we + + align:start position:0% +we do this we fit this model and then we + + + align:start position:0% +we do this we fit this model and then we +can rotate it around and change the + + align:start position:0% +can rotate it around and change the + + + align:start position:0% +can rotate it around and change the +lighting if we had parameters that + + align:start position:0% +lighting if we had parameters that + + + align:start position:0% +lighting if we had parameters that +controlled expression there's no real + + align:start position:0% +controlled expression there's no real + + + align:start position:0% +controlled expression there's no real +expression parameters here that wouldn't + + align:start position:0% +expression parameters here that wouldn't + + + align:start position:0% +expression parameters here that wouldn't +be too hard to put in you can make the + + align:start position:0% +be too hard to put in you can make the + + + align:start position:0% +be too hard to put in you can make the +face happy or sad but you can see that + + align:start position:0% +face happy or sad but you can see that + + + align:start position:0% +face happy or sad but you can see that +that hopefully what you can see is that + + align:start position:0% +that hopefully what you can see is that + + + align:start position:0% +that hopefully what you can see is that +the recovered model supports fairly + + align:start position:0% +the recovered model supports fairly + + + align:start position:0% +the recovered model supports fairly +reasonable generalization to other + + align:start position:0% +reasonable generalization to other + + + align:start position:0% +reasonable generalization to other +viewpoints and lighting conditions it's + + align:start position:0% +viewpoints and lighting conditions it's + + + align:start position:0% +viewpoints and lighting conditions it's +the sort of thing that should make for + + align:start position:0% +the sort of thing that should make for + + + align:start position:0% +the sort of thing that should make for +more robust face recognition although + + align:start position:0% +more robust face recognition although + + + align:start position:0% +more robust face recognition although +that's not the main focus of what we're + + align:start position:0% +that's not the main focus of what we're + + + align:start position:0% +that's not the main focus of what we're +trying to use it here I just want to + + align:start position:0% +trying to use it here I just want to + + + align:start position:0% +trying to use it here I just want to +emphasize there's all sorts of things + + align:start position:0% +emphasize there's all sorts of things + + + align:start position:0% +emphasize there's all sorts of things +that would be useful if you had an + + align:start position:0% +that would be useful if you had an + + + align:start position:0% +that would be useful if you had an +actual 3d model of the face you could + + align:start position:0% +actual 3d model of the face you could + + + align:start position:0% +actual 3d model of the face you could +get from a single image or here's the + + align:start position:0% +get from a single image or here's the + + + align:start position:0% +get from a single image or here's the +same kind of idea now for a body pose + + align:start position:0% +same kind of idea now for a body pose + + + align:start position:0% +same kind of idea now for a body pose +system so now the image we're going to + + align:start position:0% +system so now the image we're going to + + + align:start position:0% +system so now the image we're going to +assume has a + + align:start position:0% +assume has a + + + align:start position:0% +assume has a +in it somewhere doing something remember + + align:start position:0% +in it somewhere doing something remember + + + align:start position:0% +in it somewhere doing something remember +back to that challenge I gave at the + + align:start position:0% +back to that challenge I gave at the + + + align:start position:0% +back to that challenge I gave at the +beginning about finding the bodies in a + + align:start position:0% +beginning about finding the bodies in a + + + align:start position:0% +beginning about finding the bodies in a +complex scene like the airplane full of + + align:start position:0% +complex scene like the airplane full of + + + align:start position:0% +complex scene like the airplane full of +computer vision researchers um and and + + align:start position:0% +computer vision researchers um and and + + + align:start position:0% +computer vision researchers um and and +whereas you know you found the right + + align:start position:0% +whereas you know you found the right + + + align:start position:0% +whereas you know you found the right +hand or the left toe right so we think + + align:start position:0% +hand or the left toe right so we think + + + align:start position:0% +hand or the left toe right so we think +that in order to do that you know you + + align:start position:0% +that in order to do that you know you + + + align:start position:0% +that in order to do that you know you +think you have to have something like an + + align:start position:0% +think you have to have something like an + + + align:start position:0% +think you have to have something like an +actual 3d model of a body what you see + + align:start position:0% +actual 3d model of a body what you see + + + align:start position:0% +actual 3d model of a body what you see +on the lower left is a bunch of samples + + align:start position:0% +on the lower left is a bunch of samples + + + align:start position:0% +on the lower left is a bunch of samples +from this so we basically just took a + + align:start position:0% +from this so we basically just took a + + + align:start position:0% +from this so we basically just took a +kind of an interesting 3d stick figure + + align:start position:0% +kind of an interesting 3d stick figure + + + align:start position:0% +kind of an interesting 3d stick figure +skeleton model and just put some some + + align:start position:0% +skeleton model and just put some some + + + align:start position:0% +skeleton model and just put some some +knobs on it you can tweak it around you + + align:start position:0% +knobs on it you can tweak it around you + + + align:start position:0% +knobs on it you can tweak it around you +can put some simple probability models + + align:start position:0% +can put some simple probability models + + + align:start position:0% +can put some simple probability models +to get a prior and these are just random + + align:start position:0% +to get a prior and these are just random + + + align:start position:0% +to get a prior and these are just random +samples of random body positions and the + + align:start position:0% +samples of random body positions and the + + + align:start position:0% +samples of random body positions and the +idea of the system is to kind of search + + align:start position:0% +idea of the system is to kind of search + + + align:start position:0% +idea of the system is to kind of search +through that space of body positions + + align:start position:0% +through that space of body positions + + + align:start position:0% +through that space of body positions +until you find one that which then when + + align:start position:0% +until you find one that which then when + + + align:start position:0% +until you find one that which then when +you project it from a certain camera + + align:start position:0% +you project it from a certain camera + + + align:start position:0% +you project it from a certain camera +angle looks like the body you're seeing + + align:start position:0% +angle looks like the body you're seeing + + + align:start position:0% +angle looks like the body you're seeing +so here's an example of this in action + + align:start position:0% +so here's an example of this in action + + + align:start position:0% +so here's an example of this in action +this is some guy I guess Usain Bolt so + + align:start position:0% +this is some guy I guess Usain Bolt so + + + align:start position:0% +this is some guy I guess Usain Bolt so +I'm kind of interesting slightly unusual + + align:start position:0% +I'm kind of interesting slightly unusual + + + align:start position:0% +I'm kind of interesting slightly unusual +pose as he's about to break the finish + + align:start position:0% +pose as he's about to break the finish + + + align:start position:0% +pose as he's about to break the finish +line maybe and here's the system in + + align:start position:0% +line maybe and here's the system in + + + align:start position:0% +line maybe and here's the system in +action so it starts off from a random + + align:start position:0% +action so it starts off from a random + + + align:start position:0% +action so it starts off from a random +position and again sort of takes some + + align:start position:0% +position and again sort of takes some + + + align:start position:0% +position and again sort of takes some +sticks a bunch of random steps in moving + + align:start position:0% +sticks a bunch of random steps in moving + + + align:start position:0% +sticks a bunch of random steps in moving +around in 3d space until it finds a + + align:start position:0% +around in 3d space until it finds a + + + align:start position:0% +around in 3d space until it finds a +configuration which when you project it + + align:start position:0% +configuration which when you project it + + + align:start position:0% +configuration which when you project it +into the image looks like what you see + + align:start position:0% +into the image looks like what you see + + + align:start position:0% +into the image looks like what you see +there now just wants a notice a key + + align:start position:0% +there now just wants a notice a key + + + align:start position:0% +there now just wants a notice a key +difference when I say looks like it + + align:start position:0% +difference when I say looks like it + + + align:start position:0% +difference when I say looks like it +doesn't look like it at the pixel level + + align:start position:0% +doesn't look like it at the pixel level + + + align:start position:0% +doesn't look like it at the pixel level +like the face did right it's only + + align:start position:0% +like the face did right it's only + + + align:start position:0% +like the face did right it's only +matching at the level of these basically + + align:start position:0% +matching at the level of these basically + + + align:start position:0% +matching at the level of these basically +enhanced edge statistics which you see + + align:start position:0% +enhanced edge statistics which you see + + + align:start position:0% +enhanced edge statistics which you see +here so this is an example of building a + + align:start position:0% +here so this is an example of building a + + + align:start position:0% +here so this is an example of building a +model it's not a photorealistic render + + align:start position:0% +model it's not a photorealistic render + + + align:start position:0% +model it's not a photorealistic render +it's this is this is the graphics model + + align:start position:0% +it's this is this is the graphics model + + + align:start position:0% +it's this is this is the graphics model +is all is not trying to match the image + + align:start position:0% +is all is not trying to match the image + + + align:start position:0% +is all is not trying to match the image +it's trying to match this or it could be + + align:start position:0% +it's trying to match this or it could be + + + align:start position:0% +it's trying to match this or it could be +for example some intermediate level of + + align:start position:0% +for example some intermediate level of + + + align:start position:0% +for example some intermediate level of +continent features and we think this is + + align:start position:0% +continent features and we think this is + + + align:start position:0% +continent features and we think this is +very powerful because more generally + + align:start position:0% +very powerful because more generally + + + align:start position:0% +very powerful because more generally +while we might have a really detailed + + align:start position:0% +while we might have a really detailed + + + align:start position:0% +while we might have a really detailed +model of facial appearance you know for + + align:start position:0% +model of facial appearance you know for + + + align:start position:0% +model of facial appearance you know for +bodies we don't have a good clothing + + align:start position:0% +bodies we don't have a good clothing + + + align:start position:0% +bodies we don't have a good clothing +model we're not trying to model the skin + + align:start position:0% +model we're not trying to model the skin + + + align:start position:0% +model we're not trying to model the skin +it's you know it's it's we're just + + align:start position:0% +it's you know it's it's we're just + + + align:start position:0% +it's you know it's it's we're just +trying to model just enough to solve the + + align:start position:0% +trying to model just enough to solve the + + + align:start position:0% +trying to model just enough to solve the +problem were interested in and again + + align:start position:0% +problem were interested in and again + + + align:start position:0% +problem were interested in and again +this is reflective of a much more broad + + align:start position:0% +this is reflective of a much more broad + + + align:start position:0% +this is reflective of a much more broad +theme and this idea of intelligence as + + align:start position:0% +theme and this idea of intelligence as + + + align:start position:0% +theme and this idea of intelligence as +explanation called you know modeling the + + align:start position:0% +explanation called you know modeling the + + + align:start position:0% +explanation called you know modeling the +causal structure of the world we don't + + align:start position:0% +causal structure of the world we don't + + + align:start position:0% +causal structure of the world we don't +expect even in science but certainly not + + align:start position:0% +expect even in science but certainly not + + + align:start position:0% +expect even in science but certainly not +in our intuitive theories to model the + + align:start position:0% +in our intuitive theories to model the + + + align:start position:0% +in our intuitive theories to model the +causal structure of the world at full + + align:start position:0% +causal structure of the world at full + + + align:start position:0% +causal structure of the world at full +detail and a way that either I am always + + align:start position:0% +detail and a way that either I am always + + + align:start position:0% +detail and a way that either I am always +misunderstood or always fail to + + align:start position:0% +misunderstood or always fail to + + + align:start position:0% +misunderstood or always fail to +communicate it's my fault really + + align:start position:0% +communicate it's my fault really + + + align:start position:0% +communicate it's my fault really +as I say oh we have these rich models of + + align:start position:0% +as I say oh we have these rich models of + + + align:start position:0% +as I say oh we have these rich models of +the world people often think that means + + align:start position:0% +the world people often think that means + + + align:start position:0% +the world people often think that means +that somehow the complete thing like if + + align:start position:0% +that somehow the complete thing like if + + + align:start position:0% +that somehow the complete thing like if +I say we have a physics engine in our + + align:start position:0% +I say we have a physics engine in our + + + align:start position:0% +I say we have a physics engine in our +head it means we have all of physics or + + align:start position:0% +head it means we have all of physics or + + + align:start position:0% +head it means we have all of physics or +if I say we have a graphics engine and + + align:start position:0% +if I say we have a graphics engine and + + + align:start position:0% +if I say we have a graphics engine and +we have all of every possible thing you + + align:start position:0% +we have all of every possible thing you + + + align:start position:0% +we have all of every possible thing you +know this isn't Pixar okay we're not + + align:start position:0% +know this isn't Pixar okay we're not + + + align:start position:0% +know this isn't Pixar okay we're not +trying to make a beautiful movie except + + align:start position:0% +trying to make a beautiful movie except + + + align:start position:0% +trying to make a beautiful movie except +maybe four faces right we're just trying + + align:start position:0% +maybe four faces right we're just trying + + + align:start position:0% +maybe four faces right we're just trying +to capture just the key parts just the + + align:start position:0% +to capture just the key parts just the + + + align:start position:0% +to capture just the key parts just the +key calls all parts of the way things + + align:start position:0% +key calls all parts of the way things + + + align:start position:0% +key calls all parts of the way things +move in the world as physical objects + + align:start position:0% +move in the world as physical objects + + + align:start position:0% +move in the world as physical objects +and the way images are formed that at + + align:start position:0% +and the way images are formed that at + + + align:start position:0% +and the way images are formed that at +the right level of abstraction that + + align:start position:0% +the right level of abstraction that + + + align:start position:0% +the right level of abstraction that +matters for us allows us to to do what + + align:start position:0% +matters for us allows us to to do what + + + align:start position:0% +matters for us allows us to to do what +we need to do this is just an example of + + align:start position:0% +we need to do this is just an example of + + + align:start position:0% +we need to do this is just an example of +our system doing solving some pretty + + align:start position:0% +our system doing solving some pretty + + + align:start position:0% +our system doing solving some pretty +challenging body pose recognition + + align:start position:0% +challenging body pose recognition + + + align:start position:0% +challenging body pose recognition +problems in 3d which cases which pose + + align:start position:0% +problems in 3d which cases which pose + + + align:start position:0% +problems in 3d which cases which pose +which are problematic even for the best + + align:start position:0% +which are problematic even for the best + + + align:start position:0% +which are problematic even for the best +of standard computer vision systems a + + align:start position:0% +of standard computer vision systems a + + + align:start position:0% +of standard computer vision systems a +bit either because it's a weird pose + + align:start position:0% +bit either because it's a weird pose + + + align:start position:0% +bit either because it's a weird pose +like these weird sports figures or + + align:start position:0% +like these weird sports figures or + + + align:start position:0% +like these weird sports figures or +because the body is heavily occluded and + + align:start position:0% +because the body is heavily occluded and + + + align:start position:0% +because the body is heavily occluded and +but I think again these are problems + + align:start position:0% +but I think again these are problems + + + align:start position:0% +but I think again these are problems +which people solve effortlessly and I + + align:start position:0% +which people solve effortlessly and I + + + align:start position:0% +which people solve effortlessly and I +think something like this is on the + + align:start position:0% +think something like this is on the + + + align:start position:0% +think something like this is on the +track of what we want to do you can + + align:start position:0% +track of what we want to do you can + + + align:start position:0% +track of what we want to do you can +apply the same kind of thing to more + + align:start position:0% +apply the same kind of thing to more + + + align:start position:0% +apply the same kind of thing to more +generic objects like this but I'm not + + align:start position:0% +generic objects like this but I'm not + + + align:start position:0% +generic objects like this but I'm not +gonna go into the details the last thing + + align:start position:0% +gonna go into the details the last thing + + + align:start position:0% +gonna go into the details the last thing +I want to say about vision before + + align:start position:0% +I want to say about vision before + + + align:start position:0% +I want to say about vision before +getting back to common sense for a few + + align:start position:0% +getting back to common sense for a few + + + align:start position:0% +getting back to common sense for a few +minutes is um this is and in some sense + + align:start position:0% +minutes is um this is and in some sense + + + align:start position:0% +minutes is um this is and in some sense +maybe this is the most important slide + + align:start position:0% +maybe this is the most important slide + + + align:start position:0% +maybe this is the most important slide +for the broader CBMM brains minds + + align:start position:0% +for the broader CBMM brains minds + + + align:start position:0% +for the broader CBMM brains minds +machines and cuz this is this is the the + + align:start position:0% +machines and cuz this is this is the the + + + align:start position:0% +machines and cuz this is this is the the +clearest thing I can point to to the + + align:start position:0% +clearest thing I can point to to the + + + align:start position:0% +clearest thing I can point to to the +thing I've been saying all along since + + align:start position:0% +thing I've been saying all along since + + + align:start position:0% +thing I've been saying all along since +the beginning of the morning about how + + align:start position:0% +the beginning of the morning about how + + + align:start position:0% +the beginning of the morning about how +we want to look for ways to combine the + + align:start position:0% +we want to look for ways to combine the + + + align:start position:0% +we want to look for ways to combine the +generative model view and the pattern + + align:start position:0% +generative model view and the pattern + + + align:start position:0% +generative model view and the pattern +recognition view right so the generative + + align:start position:0% +recognition view right so the generative + + + align:start position:0% +recognition view right so the generative +model is what you see on the left here + + align:start position:0% +model is what you see on the left here + + + align:start position:0% +model is what you see on the left here +it's the arrows going down it's exactly + + align:start position:0% +it's the arrows going down it's exactly + + + align:start position:0% +it's the arrows going down it's exactly +just the face graphics engine the same + + align:start position:0% +just the face graphics engine the same + + + align:start position:0% +just the face graphics engine the same +thing I showed you okay um the thing on + + align:start position:0% +thing I showed you okay um the thing on + + + align:start position:0% +thing I showed you okay um the thing on +the right is a with the arrows going up + + align:start position:0% +the right is a with the arrows going up + + + align:start position:0% +the right is a with the arrows going up +is a continent basically it's a + + align:start position:0% +is a continent basically it's a + + + align:start position:0% +is a continent basically it's a +out-of-the-box café style convolutional + + align:start position:0% +out-of-the-box café style convolutional + + + align:start position:0% +out-of-the-box café style convolutional +neural net with some fully connected + + align:start position:0% +neural net with some fully connected + + + align:start position:0% +neural net with some fully connected +layers on the top and then there's a few + + align:start position:0% +layers on the top and then there's a few + + + align:start position:0% +layers on the top and then there's a few +other - arrows which represent linear + + align:start position:0% +other - arrows which represent linear + + + align:start position:0% +other - arrows which represent linear +decoders from layers of that model to + + align:start position:0% +decoders from layers of that model to + + + align:start position:0% +decoders from layers of that model to +other things which are basically parts + + align:start position:0% +other things which are basically parts + + + align:start position:0% +other things which are basically parts +of the generative model and the idea + + align:start position:0% +of the generative model and the idea + + + align:start position:0% +of the generative model and the idea +here this is work due to ill kirill + + align:start position:0% +here this is work due to ill kirill + + + align:start position:0% +here this is work due to ill kirill +durum who some of you might have met he + + align:start position:0% +durum who some of you might have met he + + + align:start position:0% +durum who some of you might have met he +was here the other day + + align:start position:0% +was here the other day + + + align:start position:0% +was here the other day +he's one of our CBMM postdocs but also + + align:start position:0% +he's one of our CBMM postdocs but also + + + align:start position:0% +he's one of our CBMM postdocs but also +joint with Tejas em with vendrick who + + align:start position:0% +joint with Tejas em with vendrick who + + + align:start position:0% +joint with Tejas em with vendrick who +you saw before + + align:start position:0% +you saw before + + + align:start position:0% +you saw before +is to try to in a sense in several + + align:start position:0% +is to try to in a sense in several + + + align:start position:0% +is to try to in a sense in several +senses combine the best of these + + align:start position:0% +senses combine the best of these + + + align:start position:0% +senses combine the best of these +perspectives to say look if we want to + + align:start position:0% +perspectives to say look if we want to + + + align:start position:0% +perspectives to say look if we want to +recognize anything or you know perceive + + align:start position:0% +recognize anything or you know perceive + + + align:start position:0% +recognize anything or you know perceive +the structure of the world richly I + + align:start position:0% +the structure of the world richly I + + + align:start position:0% +the structure of the world richly I +think it needs to be something like it + + align:start position:0% +think it needs to be something like it + + + align:start position:0% +think it needs to be something like it +this inverse graphics are inverting a + + align:start position:0% +this inverse graphics are inverting a + + + align:start position:0% +this inverse graphics are inverting a +graphics program but you saw how slow it + + align:start position:0% +graphics program but you saw how slow it + + + align:start position:0% +graphics program but you saw how slow it +was you saw how it took a couple of + + align:start position:0% +was you saw how it took a couple of + + + align:start position:0% +was you saw how it took a couple of +seconds at least on our computer just + + align:start position:0% +seconds at least on our computer just + + + align:start position:0% +seconds at least on our computer just +for faces to search for the space of + + align:start position:0% +for faces to search for the space of + + + align:start position:0% +for faces to search for the space of +faces to Club with the convincing + + align:start position:0% +faces to Club with the convincing + + + align:start position:0% +faces to Club with the convincing +hypothesis that's way too slow it + + align:start position:0% +hypothesis that's way too slow it + + + align:start position:0% +hypothesis that's way too slow it +doesn't take you that long right we know + + align:start position:0% +doesn't take you that long right we know + + + align:start position:0% +doesn't take you that long right we know +a lot about exactly how long it takes + + align:start position:0% +a lot about exactly how long it takes + + + align:start position:0% +a lot about exactly how long it takes +you from VIN Rick and Nancy's and many + + align:start position:0% +you from VIN Rick and Nancy's and many + + + align:start position:0% +you from VIN Rick and Nancy's and many +other people's work so how can we how + + align:start position:0% +other people's work so how can we how + + + align:start position:0% +other people's work so how can we how +can visually much more generally be so + + align:start position:0% +can visually much more generally be so + + + align:start position:0% +can visually much more generally be so +rich in terms of the model it builds yet + + align:start position:0% +rich in terms of the model it builds yet + + + align:start position:0% +rich in terms of the model it builds yet +so fast well here's the proposal which + + align:start position:0% +so fast well here's the proposal which + + + align:start position:0% +so fast well here's the proposal which +is to take the fast the things that are + + align:start position:0% +is to take the fast the things that are + + + align:start position:0% +is to take the fast the things that are +good at being fast like the pattern + + align:start position:0% +good at being fast like the pattern + + + align:start position:0% +good at being fast like the pattern +recognizers the deep ones and train them + + align:start position:0% +recognizers the deep ones and train them + + + align:start position:0% +recognizers the deep ones and train them +to solve the hard inference problem or + + align:start position:0% +to solve the hard inference problem or + + + align:start position:0% +to solve the hard inference problem or +at least to do most of the work it's an + + align:start position:0% +at least to do most of the work it's an + + + align:start position:0% +at least to do most of the work it's an +idea which is very heavily inspired by + + align:start position:0% +idea which is very heavily inspired by + + + align:start position:0% +idea which is very heavily inspired by +an older idea of Jeff Hinton's sometimes + + align:start position:0% +an older idea of Jeff Hinton's sometimes + + + align:start position:0% +an older idea of Jeff Hinton's sometimes +called the Helmholtz machine here the + + align:start position:0% +called the Helmholtz machine here the + + + align:start position:0% +called the Helmholtz machine here the +idea in common with Hinton is to have a + + align:start position:0% +idea in common with Hinton is to have a + + + align:start position:0% +idea in common with Hinton is to have a +generative model and a recognition model + + align:start position:0% +generative model and a recognition model + + + align:start position:0% +generative model and a recognition model +where the recognition model is a neural + + align:start position:0% +where the recognition model is a neural + + + align:start position:0% +where the recognition model is a neural +network and it's trained to invert the + + align:start position:0% +network and it's trained to invert the + + + align:start position:0% +network and it's trained to invert the +generative model namely it's trained to + + align:start position:0% +generative model namely it's trained to + + + align:start position:0% +generative model namely it's trained to +map from not from sense data to task + + align:start position:0% +map from not from sense data to task + + + align:start position:0% +map from not from sense data to task +output but from sense data to the hidden + + align:start position:0% +output but from sense data to the hidden + + + align:start position:0% +output but from sense data to the hidden +deep causes of the generative model + + align:start position:0% +deep causes of the generative model + + + align:start position:0% +deep causes of the generative model +which then when you want to use this to + + align:start position:0% +which then when you want to use this to + + + align:start position:0% +which then when you want to use this to +act right like to plan what you're going + + align:start position:0% +act right like to plan what you're going + + + align:start position:0% +act right like to plan what you're going +to do you plan on the model to make an + + align:start position:0% +to do you plan on the model to make an + + + align:start position:0% +to do you plan on the model to make an +analogy to say the deep mind video game + + align:start position:0% +analogy to say the deep mind video game + + + align:start position:0% +analogy to say the deep mind video game +player this would be like having a + + align:start position:0% +player this would be like having a + + + align:start position:0% +player this would be like having a +system which in contrast to the deep Q + + align:start position:0% +system which in contrast to the deep Q + + + align:start position:0% +system which in contrast to the deep Q +network which maps from pixel images to + + align:start position:0% +network which maps from pixel images to + + + align:start position:0% +network which maps from pixel images to +joystick commands this would be like + + align:start position:0% +joystick commands this would be like + + + align:start position:0% +joystick commands this would be like +learning a network that maps from pixel + + align:start position:0% +learning a network that maps from pixel + + + align:start position:0% +learning a network that maps from pixel +images to the game state to the objects + + align:start position:0% +images to the game state to the objects + + + align:start position:0% +images to the game state to the objects +the sprites that are moving around the + + align:start position:0% +the sprites that are moving around the + + + align:start position:0% +the sprites that are moving around the +score and so on and then plans on that + + align:start position:0% +score and so on and then plans on that + + + align:start position:0% +score and so on and then plans on that +and I think that's much more like what + + align:start position:0% +and I think that's much more like what + + + align:start position:0% +and I think that's much more like what +people do is it is that here just in the + + align:start position:0% +people do is it is that here just in the + + + align:start position:0% +people do is it is that here just in the +limited case of faces what are we doing + + align:start position:0% +limited case of faces what are we doing + + + align:start position:0% +limited case of faces what are we doing +right so um what we what we've got here + + align:start position:0% +right so um what we what we've got here + + + align:start position:0% +right so um what we what we've got here +is we take this convolutional neural + + align:start position:0% +is we take this convolutional neural + + + align:start position:0% +is we take this convolutional neural +network we train it in ways that you can + + align:start position:0% +network we train it in ways that you can + + + align:start position:0% +network we train it in ways that you can +read about in the paper it's very easy + + align:start position:0% +read about in the paper it's very easy + + + align:start position:0% +read about in the paper it's very easy +kind of training to basically make + + align:start position:0% +kind of training to basically make + + + align:start position:0% +kind of training to basically make +predictions to make guesses about all + + align:start position:0% +predictions to make guesses about all + + + align:start position:0% +predictions to make guesses about all +the latent variables the shape the + + align:start position:0% +the latent variables the shape the + + + align:start position:0% +the latent variables the shape the +texture the lighting that the camera + + align:start position:0% +texture the lighting that the camera + + + align:start position:0% +texture the lighting that the camera +angle and then you take those guesses + + align:start position:0% +angle and then you take those guesses + + + align:start position:0% +angle and then you take those guesses +and they're there they start off that + + align:start position:0% +and they're there they start off that + + + align:start position:0% +and they're there they start off that +Markov chains once + + align:start position:0% +Markov chains once + + + align:start position:0% +Markov chains once +of starting off at a random graphics + + align:start position:0% +of starting off at a random graphics + + + align:start position:0% +of starting off at a random graphics +hypothesis you start off at a pretty + + align:start position:0% +hypothesis you start off at a pretty + + + align:start position:0% +hypothesis you start off at a pretty +good one and then refine it a little bit + + align:start position:0% +good one and then refine it a little bit + + + align:start position:0% +good one and then refine it a little bit +what you can see here in these blue and + + align:start position:0% +what you can see here in these blue and + + + align:start position:0% +what you can see here in these blue and +red curves is the blue curve is the the + + align:start position:0% +red curves is the blue curve is the the + + + align:start position:0% +red curves is the blue curve is the the +the dinette that the course of inference + + align:start position:0% +the dinette that the course of inference + + + align:start position:0% +the dinette that the course of inference +for the model I showed you before where + + align:start position:0% +for the model I showed you before where + + + align:start position:0% +for the model I showed you before where +you start off at a random guess and you + + align:start position:0% +you start off at a random guess and you + + + align:start position:0% +you start off at a random guess and you +know after I don't know 100 iterations + + align:start position:0% +know after I don't know 100 iterations + + + align:start position:0% +know after I don't know 100 iterations +of MCMC you you improve and you kind of + + align:start position:0% +of MCMC you you improve and you kind of + + + align:start position:0% +of MCMC you you improve and you kind of +get there whereas the red curve is what + + align:start position:0% +get there whereas the red curve is what + + + align:start position:0% +get there whereas the red curve is what +you see if you start off with the guess + + align:start position:0% +you see if you start off with the guess + + + align:start position:0% +you see if you start off with the guess +of this recognition model and you can + + align:start position:0% +of this recognition model and you can + + + align:start position:0% +of this recognition model and you can +see that you start off sort of in some + + align:start position:0% +see that you start off sort of in some + + + align:start position:0% +see that you start off sort of in some +sense almost as good as you're ever + + align:start position:0% +sense almost as good as you're ever + + + align:start position:0% +sense almost as good as you're ever +going to get and then you refine it well + + align:start position:0% +going to get and then you refine it well + + + align:start position:0% +going to get and then you refine it well +it might look like you were just + + align:start position:0% +it might look like you were just + + + align:start position:0% +it might look like you were just +refining it a little bit but this is a + + align:start position:0% +refining it a little bit but this is a + + + align:start position:0% +refining it a little bit but this is a +kind of a EE log scale it's a log plot + + align:start position:0% +kind of a EE log scale it's a log plot + + + align:start position:0% +kind of a EE log scale it's a log plot +of log probability so what looks like a + + align:start position:0% +of log probability so what looks like a + + + align:start position:0% +of log probability so what looks like a +little bit there on the red curve is + + align:start position:0% +little bit there on the red curve is + + + align:start position:0% +little bit there on the red curve is +actually a lot I mean perceptually you + + align:start position:0% +actually a lot I mean perceptually you + + + align:start position:0% +actually a lot I mean perceptually you +can see it here where if you take on the + + align:start position:0% +can see it here where if you take on the + + + align:start position:0% +can see it here where if you take on the +top I'm showing observed input faces on + + align:start position:0% +top I'm showing observed input faces on + + + align:start position:0% +top I'm showing observed input faces on +the bottom I'm showing the results of + + align:start position:0% +the bottom I'm showing the results of + + + align:start position:0% +the bottom I'm showing the results of +this full inverse graphics thing and + + align:start position:0% +this full inverse graphics thing and + + + align:start position:0% +this full inverse graphics thing and +they should look almost identical so if + + align:start position:0% +they should look almost identical so if + + + align:start position:0% +they should look almost identical so if +you if you the full model is able to + + align:start position:0% +you if you the full model is able to + + + align:start position:0% +you if you the full model is able to +basically perfectly invert this and come + + align:start position:0% +basically perfectly invert this and come + + + align:start position:0% +basically perfectly invert this and come +up with a face that really does look + + align:start position:0% +up with a face that really does look + + + align:start position:0% +up with a face that really does look +like on the top the ones in the middle + + align:start position:0% +like on the top the ones in the middle + + + align:start position:0% +like on the top the ones in the middle +are the best guess you get from this + + align:start position:0% +are the best guess you get from this + + + align:start position:0% +are the best guess you get from this +neural network that's been trained to + + align:start position:0% +neural network that's been trained to + + + align:start position:0% +neural network that's been trained to +approximately invert the generative + + align:start position:0% +approximately invert the generative + + + align:start position:0% +approximately invert the generative +model and what you can see is on first + + align:start position:0% +model and what you can see is on first + + + align:start position:0% +model and what you can see is on first +glance it should look pretty good but if + + align:start position:0% +glance it should look pretty good but if + + + align:start position:0% +glance it should look pretty good but if +you if you pay a little bit of attention + + align:start position:0% +you if you pay a little bit of attention + + + align:start position:0% +you if you pay a little bit of attention +you can see differences right like + + align:start position:0% +you can see differences right like + + + align:start position:0% +you can see differences right like +hopefully you can see this person is not + + align:start position:0% +hopefully you can see this person is not + + + align:start position:0% +hopefully you can see this person is not +actually that person in a way that this + + align:start position:0% +actually that person in a way that this + + + align:start position:0% +actually that person in a way that this +is much more convincingly or you know + + align:start position:0% +is much more convincingly or you know + + + align:start position:0% +is much more convincingly or you know +this person this one's pretty good but I + + align:start position:0% +this person this one's pretty good but I + + + align:start position:0% +this person this one's pretty good but I +think this one I think it's it's pretty + + align:start position:0% +think this one I think it's it's pretty + + + align:start position:0% +think this one I think it's it's pretty +easy to see yeah this isn't quite the + + align:start position:0% +easy to see yeah this isn't quite the + + + align:start position:0% +easy to see yeah this isn't quite the +same person as that one you guys agree + + align:start position:0% +same person as that one you guys agree + + + align:start position:0% +same person as that one you guys agree +we've we've done some experiments to + + align:start position:0% +we've we've done some experiments to + + + align:start position:0% +we've we've done some experiments to +verify this but hopefully it should look + + align:start position:0% +verify this but hopefully it should look + + + align:start position:0% +verify this but hopefully it should look +pretty similar that's the point right + + align:start position:0% +pretty similar that's the point right + + + align:start position:0% +pretty similar that's the point right +that that this that you you know how do + + align:start position:0% +that that this that you you know how do + + + align:start position:0% +that that this that you you know how do +you combine the best of these + + align:start position:0% +you combine the best of these + + + align:start position:0% +you combine the best of these +computational paradigms how can + + align:start position:0% +computational paradigms how can + + + align:start position:0% +computational paradigms how can +perception more generally be so rich it + + align:start position:0% +perception more generally be so rich it + + + align:start position:0% +perception more generally be so rich it +so fast well quite possibly like this it + + align:start position:0% +so fast well quite possibly like this it + + + align:start position:0% +so fast well quite possibly like this it +even actually might provide some some + + align:start position:0% +even actually might provide some some + + + align:start position:0% +even actually might provide some some +insight into the neural circuitry that + + align:start position:0% +insight into the neural circuitry that + + + align:start position:0% +insight into the neural circuitry that +Vin Rick and Dora saw and others have + + align:start position:0% +Vin Rick and Dora saw and others have + + + align:start position:0% +Vin Rick and Dora saw and others have +mapped out we think that this + + align:start position:0% +mapped out we think that this + + + align:start position:0% +mapped out we think that this +recognition model that's trained to + + align:start position:0% +recognition model that's trained to + + + align:start position:0% +recognition model that's trained to +invert the graphics model can provide a + + align:start position:0% +invert the graphics model can provide a + + + align:start position:0% +invert the graphics model can provide a +really nice account of some of vinner X + + align:start position:0% +really nice account of some of vinner X + + + align:start position:0% +really nice account of some of vinner X +data like you saw before but I will not + + align:start position:0% +data like you saw before but I will not + + + align:start position:0% +data like you saw before but I will not +go into the details because in maybe + + align:start position:0% +go into the details because in maybe + + + align:start position:0% +go into the details because in maybe +five to ten minutes I want to get back + + align:start position:0% +five to ten minutes I want to get back + + + align:start position:0% +five to ten minutes I want to get back +to physics and psychology okay + + align:start position:0% +to physics and psychology okay + + + align:start position:0% +to physics and psychology okay +so physics and and and there won't be + + align:start position:0% +so physics and and and there won't be + + + align:start position:0% +so physics and and and there won't be +any more neural networks because that's + + align:start position:0% +any more neural networks because that's + + + align:start position:0% +any more neural networks because that's +about as I mean I + + align:start position:0% + + + + align:start position:0% + +I think we'd like to take that those + + align:start position:0% +I think we'd like to take that those + + + align:start position:0% +I think we'd like to take that those +ways of integrating the best of these + + align:start position:0% +ways of integrating the best of these + + + align:start position:0% +ways of integrating the best of these +approaches and apply them to these more + + align:start position:0% +approaches and apply them to these more + + + align:start position:0% +approaches and apply them to these more +general cases but that's about as far as + + align:start position:0% +general cases but that's about as far as + + + align:start position:0% +general cases but that's about as far as +we can get here what I want to just give + + align:start position:0% +we can get here what I want to just give + + + align:start position:0% +we can get here what I want to just give +you a taste of at least is how we're + + align:start position:0% +you a taste of at least is how we're + + + align:start position:0% +you a taste of at least is how we're +using ideas just purely from + + align:start position:0% +using ideas just purely from + + + align:start position:0% +using ideas just purely from +probablistic programs to capture more of + + align:start position:0% +probablistic programs to capture more of + + + align:start position:0% +probablistic programs to capture more of +this common-sense physics in psychology + + align:start position:0% +this common-sense physics in psychology + + + align:start position:0% +this common-sense physics in psychology +so let's say we can solve this problem + + align:start position:0% +so let's say we can solve this problem + + + align:start position:0% +so let's say we can solve this problem +by making a good guess of the 3d world + + align:start position:0% +by making a good guess of the 3d world + + + align:start position:0% +by making a good guess of the 3d world +state from the unit very quickly + + align:start position:0% +state from the unit very quickly + + + align:start position:0% +state from the unit very quickly +inverting this graphics engine now we + + align:start position:0% +inverting this graphics engine now we + + + align:start position:0% +inverting this graphics engine now we +can start to do some physical reasoning + + align:start position:0% +can start to do some physical reasoning + + + align:start position:0% +can start to do some physical reasoning +a la crakes you know mental model of the + + align:start position:0% +a la crakes you know mental model of the + + + align:start position:0% +a la crakes you know mental model of the +in the head of the physical world + + align:start position:0% +in the head of the physical world + + + align:start position:0% +in the head of the physical world +where we now take a physics engine which + + align:start position:0% +where we now take a physics engine which + + + align:start position:0% +where we now take a physics engine which +is a you know here again we're using the + + align:start position:0% +is a you know here again we're using the + + + align:start position:0% +is a you know here again we're using the +kind of physics engines that game + + align:start position:0% +kind of physics engines that game + + + align:start position:0% +kind of physics engines that game +physics like very simple I don't have + + align:start position:0% +physics like very simple I don't have + + + align:start position:0% +physics like very simple I don't have +time to go into the details + + align:start position:0% +time to go into the details + + + align:start position:0% +time to go into the details +although homers written a very nice + + align:start position:0% +although homers written a very nice + + + align:start position:0% +although homers written a very nice +paper with well with himself but he's + + align:start position:0% +paper with well with himself but he's + + + align:start position:0% +paper with well with himself but he's +nicely put my name and Liz's on it about + + align:start position:0% +nicely put my name and Liz's on it about + + + align:start position:0% +nicely put my name and Liz's on it about +sort of trying to introduce some of the + + align:start position:0% +sort of trying to introduce some of the + + + align:start position:0% +sort of trying to introduce some of the +basic game engine concepts to cognitive + + align:start position:0% +basic game engine concepts to cognitive + + + align:start position:0% +basic game engine concepts to cognitive +scientists so hopefully we'll be able to + + align:start position:0% +scientists so hopefully we'll be able to + + + align:start position:0% +scientists so hopefully we'll be able to +show you that soon too or you can read + + align:start position:0% +show you that soon too or you can read + + + align:start position:0% +show you that soon too or you can read +about that basically is that these + + align:start position:0% +about that basically is that these + + + align:start position:0% +about that basically is that these +physics engines are just doing again a + + align:start position:0% +physics engines are just doing again a + + + align:start position:0% +physics engines are just doing again a +very quick fast approximate + + align:start position:0% +very quick fast approximate + + + align:start position:0% +very quick fast approximate +implementation of certain aspects of + + align:start position:0% +implementation of certain aspects of + + + align:start position:0% +implementation of certain aspects of +Newtonian mechanics sufficient that if + + align:start position:0% +Newtonian mechanics sufficient that if + + + align:start position:0% +Newtonian mechanics sufficient that if +you run it a few time steps with a + + align:start position:0% +you run it a few time steps with a + + + align:start position:0% +you run it a few time steps with a +configuration of objects like that you + + align:start position:0% +configuration of objects like that you + + + align:start position:0% +configuration of objects like that you +might get something like what you see + + align:start position:0% +might get something like what you see + + + align:start position:0% +might get something like what you see +over there on the right that's an + + align:start position:0% +over there on the right that's an + + + align:start position:0% +over there on the right that's an +example of running this this approximate + + align:start position:0% +example of running this this approximate + + + align:start position:0% +example of running this this approximate +Newtonian physics forward a few time + + align:start position:0% +Newtonian physics forward a few time + + + align:start position:0% +Newtonian physics forward a few time +steps here's another sample from this + + align:start position:0% +steps here's another sample from this + + + align:start position:0% +steps here's another sample from this +model another kind of mental simulation + + align:start position:0% +model another kind of mental simulation + + + align:start position:0% +model another kind of mental simulation +we take a different slightly different + + align:start position:0% +we take a different slightly different + + + align:start position:0% +we take a different slightly different +guess of the world state naught and we + + align:start position:0% +guess of the world state naught and we + + + align:start position:0% +guess of the world state naught and we +run that forward a few time steps and + + align:start position:0% +run that forward a few time steps and + + + align:start position:0% +run that forward a few time steps and +you see something else happens right + + align:start position:0% +you see something else happens right + + + align:start position:0% +you see something else happens right +nothing here is claimed to be accurate + + align:start position:0% +nothing here is claimed to be accurate + + + align:start position:0% +nothing here is claimed to be accurate +in the ground truth way right neither + + align:start position:0% +in the ground truth way right neither + + + align:start position:0% +in the ground truth way right neither +one of these is exactly the right + + align:start position:0% +one of these is exactly the right + + + align:start position:0% +one of these is exactly the right +configuration of blocks and you run this + + align:start position:0% +configuration of blocks and you run this + + + align:start position:0% +configuration of blocks and you run this +thing forward and it only approximately + + align:start position:0% +thing forward and it only approximately + + + align:start position:0% +thing forward and it only approximately +captures the way blocks really bounce + + align:start position:0% +captures the way blocks really bounce + + + align:start position:0% +captures the way blocks really bounce +off each other it's a hard problem to + + align:start position:0% +off each other it's a hard problem to + + + align:start position:0% +off each other it's a hard problem to +actually totally realistically simulate + + align:start position:0% +actually totally realistically simulate + + + align:start position:0% +actually totally realistically simulate +but our point is that you don't really + + align:start position:0% +but our point is that you don't really + + + align:start position:0% +but our point is that you don't really +have to you just have to make a + + align:start position:0% +have to you just have to make a + + + align:start position:0% +have to you just have to make a +reasonable guess of the position of the + + align:start position:0% +reasonable guess of the position of the + + + align:start position:0% +reasonable guess of the position of the +blocks and a reasonable guess of what's + + align:start position:0% +blocks and a reasonable guess of what's + + + align:start position:0% +blocks and a reasonable guess of what's +going to happen a few time steps in the + + align:start position:0% +going to happen a few time steps in the + + + align:start position:0% +going to happen a few time steps in the +future to predict what you need to know + + align:start position:0% +future to predict what you need to know + + + align:start position:0% +future to predict what you need to know +in common sense which is that wow that's + + align:start position:0% +in common sense which is that wow that's + + + align:start position:0% +in common sense which is that wow that's +gonna fall over I better do something + + align:start position:0% +gonna fall over I better do something + + + align:start position:0% +gonna fall over I better do something +about it right and that's what our + + align:start position:0% +about it right and that's what our + + + align:start position:0% +about it right and that's what our +experiment taps into we give people a + + align:start position:0% +experiment taps into we give people a + + + align:start position:0% +experiment taps into we give people a +whole bunch of stimuli like the ones I + + align:start position:0% +whole bunch of stimuli like the ones I + + + align:start position:0% +whole bunch of stimuli like the ones I +showed you and ask them you know + + align:start position:0% +showed you and ask them you know + + + align:start position:0% +showed you and ask them you know +underground some graded scale how likely + + align:start position:0% +underground some graded scale how likely + + + align:start position:0% +underground some graded scale how likely +do you think it is to fall over and what + + align:start position:0% +do you think it is to fall over and what + + + align:start position:0% +do you think it is to fall over and what +you see here this is again one of those + + align:start position:0% +you see here this is again one of those + + + align:start position:0% +you see here this is again one of those +plots that always are + + align:start position:0% +plots that always are + + + align:start position:0% +plots that always are +the same where on the y-axis are the + + align:start position:0% +the same where on the y-axis are the + + + align:start position:0% +the same where on the y-axis are the +average human judgments now of it's an + + align:start position:0% +average human judgments now of it's an + + + align:start position:0% +average human judgments now of it's an +estimate of how unstable the tower is + + align:start position:0% +estimate of how unstable the tower is + + + align:start position:0% +estimate of how unstable the tower is +it's both the probability that it will + + align:start position:0% +it's both the probability that it will + + + align:start position:0% +it's both the probability that it will +fall but also how much of the tower will + + align:start position:0% +fall but also how much of the tower will + + + align:start position:0% +fall but also how much of the tower will +fall so it's like the expected + + align:start position:0% +fall so it's like the expected + + + align:start position:0% +fall so it's like the expected +proportion of the tower that's gonna + + align:start position:0% +proportion of the tower that's gonna + + + align:start position:0% +proportion of the tower that's gonna +fall over under gravity and along the + + align:start position:0% +fall over under gravity and along the + + + align:start position:0% +fall over under gravity and along the +x-axis is the model prediction which is + + align:start position:0% +x-axis is the model prediction which is + + + align:start position:0% +x-axis is the model prediction which is +just the average of a few samples from + + align:start position:0% +just the average of a few samples from + + + align:start position:0% +just the average of a few samples from +what I showed you you just take a few + + align:start position:0% +what I showed you you just take a few + + + align:start position:0% +what I showed you you just take a few +guesses of the world state run it + + align:start position:0% +guesses of the world state run it + + + align:start position:0% +guesses of the world state run it +forward a few time steps count up the + + align:start position:0% +forward a few time steps count up the + + + align:start position:0% +forward a few time steps count up the +proportion of blocks that fell and + + align:start position:0% +proportion of blocks that fell and + + + align:start position:0% +proportion of blocks that fell and +that's in that an average that and what + + align:start position:0% +that's in that an average that and what + + + align:start position:0% +that's in that an average that and what +you can see is that does a really nice + + align:start position:0% +you can see is that does a really nice + + + align:start position:0% +you can see is that does a really nice +job of predicting people's stability + + align:start position:0% +job of predicting people's stability + + + align:start position:0% +job of predicting people's stability +intuitions um i-i'll just point to what + + align:start position:0% +intuitions um i-i'll just point to what + + + align:start position:0% +intuitions um i-i'll just point to what +an interesting comparison because it + + align:start position:0% +an interesting comparison because it + + + align:start position:0% +an interesting comparison because it +does come in too weird where does the + + align:start position:0% +does come in too weird where does the + + + align:start position:0% +does come in too weird where does the +probability come in into these public + + align:start position:0% +probability come in into these public + + + align:start position:0% +probability come in into these public +programs well here's one very noticeable + + align:start position:0% +programs well here's one very noticeable + + + align:start position:0% +programs well here's one very noticeable +way so if you look down there on the + + align:start position:0% +way so if you look down there on the + + + align:start position:0% +way so if you look down there on the +lower right you'll see a smaller version + + align:start position:0% +lower right you'll see a smaller version + + + align:start position:0% +lower right you'll see a smaller version +of a similar plot which is um it's + + align:start position:0% +of a similar plot which is um it's + + + align:start position:0% +of a similar plot which is um it's +plotting now the results of it says + + align:start position:0% +plotting now the results of it says + + + align:start position:0% +plotting now the results of it says +ground truth physics but that's a little + + align:start position:0% +ground truth physics but that's a little + + + align:start position:0% +ground truth physics but that's a little +misleading maybe it's just a noiseless + + align:start position:0% +misleading maybe it's just a noiseless + + + align:start position:0% +misleading maybe it's just a noiseless +extension so we take the same physics + + align:start position:0% +extension so we take the same physics + + + align:start position:0% +extension so we take the same physics +model but we get rid of any of the state + + align:start position:0% +model but we get rid of any of the state + + + align:start position:0% +model but we get rid of any of the state +uncertainty so we tell it the exact the + + align:start position:0% +uncertainty so we tell it the exact the + + + align:start position:0% +uncertainty so we tell it the exact the +true position of the blocks and we give + + align:start position:0% +true position of the blocks and we give + + + align:start position:0% +true position of the blocks and we give +it the true physics whereas this our + + align:start position:0% +it the true physics whereas this our + + + align:start position:0% +it the true physics whereas this our +published stick physics engine allows + + align:start position:0% +published stick physics engine allows + + + align:start position:0% +published stick physics engine allows +for some uncertainty and exactly which + + align:start position:0% +for some uncertainty and exactly which + + + align:start position:0% +for some uncertainty and exactly which +forces are doing what but here we say + + align:start position:0% +forces are doing what but here we say + + + align:start position:0% +forces are doing what but here we say +we're just going to model gravity + + align:start position:0% +we're just going to model gravity + + + align:start position:0% +we're just going to model gravity +friction collisions as best we can and + + align:start position:0% +friction collisions as best we can and + + + align:start position:0% +friction collisions as best we can and +we're gonna get the state of the blocks + + align:start position:0% +we're gonna get the state of the blocks + + + align:start position:0% +we're gonna get the state of the blocks +perfectly and because it's noiseless you + + align:start position:0% +perfectly and because it's noiseless you + + + align:start position:0% +perfectly and because it's noiseless you +notice that so those those crosses over + + align:start position:0% +notice that so those those crosses over + + + align:start position:0% +notice that so those those crosses over +there are crosses because their error + + align:start position:0% +there are crosses because their error + + + align:start position:0% +there are crosses because their error +bar is both across people and model + + align:start position:0% +bar is both across people and model + + + align:start position:0% +bar is both across people and model +simulations now they're just vertical + + align:start position:0% +simulations now they're just vertical + + + align:start position:0% +simulations now they're just vertical +lines there's no error bars in the model + + align:start position:0% +lines there's no error bars in the model + + + align:start position:0% +lines there's no error bars in the model +simulation because it's deterministic + + align:start position:0% +simulation because it's deterministic + + + align:start position:0% +simulation because it's deterministic +its graded because of there's the + + align:start position:0% +its graded because of there's the + + + align:start position:0% +its graded because of there's the +proportion of the tower that falls over + + align:start position:0% +proportion of the tower that falls over + + + align:start position:0% +proportion of the tower that falls over +but what you see is the models a lot + + align:start position:0% +but what you see is the models a lot + + + align:start position:0% +but what you see is the models a lot +worse right it scatters much more the + + align:start position:0% +worse right it scatters much more the + + + align:start position:0% +worse right it scatters much more the +correlation drops from around point nine + + align:start position:0% +correlation drops from around point nine + + + align:start position:0% +correlation drops from around point nine +to around point six in terms of + + align:start position:0% +to around point six in terms of + + + align:start position:0% +to around point six in terms of +correlation of model with people's + + align:start position:0% +correlation of model with people's + + + align:start position:0% +correlation of model with people's +judgments and you have some cases like + + align:start position:0% +judgments and you have some cases like + + + align:start position:0% +judgments and you have some cases like +this red dot here that corresponds to + + align:start position:0% +this red dot here that corresponds to + + + align:start position:0% +this red dot here that corresponds to +this stimulus which goes from being a + + align:start position:0% +this stimulus which goes from being a + + + align:start position:0% +this stimulus which goes from being a +really nice model fit this is one which + + align:start position:0% +really nice model fit this is one which + + + align:start position:0% +really nice model fit this is one which +people judged to be very unstable and so + + align:start position:0% +people judged to be very unstable and so + + + align:start position:0% +people judged to be very unstable and so +does the probabilistic physics engine + + align:start position:0% +does the probabilistic physics engine + + + align:start position:0% +does the probabilistic physics engine +but actually it's not state it's not + + align:start position:0% +but actually it's not state it's not + + + align:start position:0% +but actually it's not state it's not +unstable at all it's actually perfectly + + align:start position:0% +unstable at all it's actually perfectly + + + align:start position:0% +unstable at all it's actually perfectly +stable the blocks are actually just + + align:start position:0% +stable the blocks are actually just + + + align:start position:0% +stable the blocks are actually just +perfectly balanced so that it doesn't + + align:start position:0% +perfectly balanced so that it doesn't + + + align:start position:0% +perfectly balanced so that it doesn't +fall although I'm sure everybody looks + + align:start position:0% +fall although I'm sure everybody looks + + + align:start position:0% +fall although I'm sure everybody looks +at that and finds that hard to believe + + align:start position:0% +at that and finds that hard to believe + + + align:start position:0% +at that and finds that hard to believe +right okay so this is nice this is a + + align:start position:0% +right okay so this is nice this is a + + + align:start position:0% +right okay so this is nice this is a +kind of physics illusion there are + + align:start position:0% +kind of physics illusion there are + + + align:start position:0% +kind of physics illusion there are +real-world versions of this out on the + + align:start position:0% +real-world versions of this out on the + + + align:start position:0% +real-world versions of this out on the +beaches not too far from here people + + align:start position:0% +beaches not too far from here people + + + align:start position:0% +beaches not too far from here people +like it's a fun thing to do to stock up + + align:start position:0% +like it's a fun thing to do to stock up + + + align:start position:0% +like it's a fun thing to do to stock up +in ways that are surprisingly stable we + + align:start position:0% +in ways that are surprisingly stable we + + + align:start position:0% +in ways that are surprisingly stable we +would say their surprise surprise + + align:start position:0% +would say their surprise surprise + + + align:start position:0% +would say their surprise surprise +because your intuitive physics has + + align:start position:0% +because your intuitive physics has + + + align:start position:0% +because your intuitive physics has +certain irreducible noise you can't + + align:start position:0% +certain irreducible noise you can't + + + align:start position:0% +certain irreducible noise you can't +we're suggesting here is that your + + align:start position:0% +we're suggesting here is that your + + + align:start position:0% +we're suggesting here is that your +physical intuitions you just you you + + align:start position:0% +physical intuitions you just you you + + + align:start position:0% +physical intuitions you just you you +you're always in some sense making a + + align:start position:0% +you're always in some sense making a + + + align:start position:0% +you're always in some sense making a +guess that's sensitive to the to the + + align:start position:0% +guess that's sensitive to the to the + + + align:start position:0% +guess that's sensitive to the to the +uncertainty about where things might be + + align:start position:0% +uncertainty about where things might be + + + align:start position:0% +uncertainty about where things might be +and what forces might be active on the + + align:start position:0% +and what forces might be active on the + + + align:start position:0% +and what forces might be active on the +world and it's very hard to see these as + + align:start position:0% +world and it's very hard to see these as + + + align:start position:0% +world and it's very hard to see these as +deterministic physics even when you know + + align:start position:0% +deterministic physics even when you know + + + align:start position:0% +deterministic physics even when you know +that that's exactly what's going on in + + align:start position:0% +that that's exactly what's going on in + + + align:start position:0% +that that's exactly what's going on in +that it is stable let me say just a + + align:start position:0% +that it is stable let me say just a + + + align:start position:0% +that it is stable let me say just a +little bit about planning right so how + + align:start position:0% +little bit about planning right so how + + + align:start position:0% +little bit about planning right so how +might you use this kind of model to + + align:start position:0% +might you use this kind of model to + + + align:start position:0% +might you use this kind of model to +build some model of you know this + + align:start position:0% +build some model of you know this + + + align:start position:0% +build some model of you know this +intuitive core intuitive psychology and + + align:start position:0% +intuitive core intuitive psychology and + + + align:start position:0% +intuitive core intuitive psychology and +I don't mean here all of theory of mind + + align:start position:0% +I don't mean here all of theory of mind + + + align:start position:0% +I don't mean here all of theory of mind +well here next week will hear a lot more + + align:start position:0% +well here next week will hear a lot more + + + align:start position:0% +well here next week will hear a lot more +like Rebecca Saxe will be down here + + align:start position:0% +like Rebecca Saxe will be down here + + + align:start position:0% +like Rebecca Saxe will be down here +we'll hear a lot more about much richer + + align:start position:0% +we'll hear a lot more about much richer + + + align:start position:0% +we'll hear a lot more about much richer +kinds of reasoning about other people's + + align:start position:0% +kinds of reasoning about other people's + + + align:start position:0% +kinds of reasoning about other people's +mental states that adults and older + + align:start position:0% +mental states that adults and older + + + align:start position:0% +mental states that adults and older +children can do but here we're talking + + align:start position:0% +children can do but here we're talking + + + align:start position:0% +children can do but here we're talking +about just as just as we were talking + + align:start position:0% +about just as just as we were talking + + + align:start position:0% +about just as just as we were talking +about what I was calling core intuitive + + align:start position:0% +about what I was calling core intuitive + + + align:start position:0% +about what I was calling core intuitive +physics again inspired by Liz's work of + + align:start position:0% +physics again inspired by Liz's work of + + + align:start position:0% +physics again inspired by Liz's work of +just you know what one objects do right + + align:start position:0% +just you know what one objects do right + + + align:start position:0% +just you know what one objects do right +here on the tabletop around us over + + align:start position:0% +here on the tabletop around us over + + + align:start position:0% +here on the tabletop around us over +short timescales the kind of core theory + + align:start position:0% +short timescales the kind of core theory + + + align:start position:0% +short timescales the kind of core theory +of mind something that even very young + + align:start position:0% +of mind something that even very young + + + align:start position:0% +of mind something that even very young +babies can do in some form or at least + + align:start position:0% +babies can do in some form or at least + + + align:start position:0% +babies can do in some form or at least +young children is controversy over + + align:start position:0% +young children is controversy over + + + align:start position:0% +young children is controversy over +exactly what age kids be able to do this + + align:start position:0% +exactly what age kids be able to do this + + + align:start position:0% +exactly what age kids be able to do this +can be able to do this sort of thing but + + align:start position:0% +can be able to do this sort of thing but + + + align:start position:0% +can be able to do this sort of thing but +you know in some form I think before + + align:start position:0% +you know in some form I think before + + + align:start position:0% +you know in some form I think before +certain before language it's the kind of + + align:start position:0% +certain before language it's the kind of + + + align:start position:0% +certain before language it's the kind of +thing that when you're starting to learn + + align:start position:0% +thing that when you're starting to learn + + + align:start position:0% +thing that when you're starting to learn +verbs the earliest language is kind of + + align:start position:0% +verbs the earliest language is kind of + + + align:start position:0% +verbs the earliest language is kind of +mentalistic and builds on this knowledge + + align:start position:0% +mentalistic and builds on this knowledge + + + align:start position:0% +mentalistic and builds on this knowledge +and and you know the intake the the red + + align:start position:0% +and and you know the intake the the red + + + align:start position:0% +and and you know the intake the the red +and blue ball chasing scene that you saw + + align:start position:0% +and blue ball chasing scene that you saw + + + align:start position:0% +and blue ball chasing scene that you saw +remember from Tomer that was 13 month + + align:start position:0% +remember from Tomer that was 13 month + + + align:start position:0% +remember from Tomer that was 13 month +old so there's definitely some form of + + align:start position:0% +old so there's definitely some form of + + + align:start position:0% +old so there's definitely some form of +kind of interpretation of beliefs and + + align:start position:0% +kind of interpretation of beliefs and + + + align:start position:0% +kind of interpretation of beliefs and +desires in some proto form that you can + + align:start position:0% +desires in some proto form that you can + + + align:start position:0% +desires in some proto form that you can +see even in in infants of around one + + align:start position:0% +see even in in infants of around one + + + align:start position:0% +see even in in infants of around one +year of age and it's it's exactly that + + align:start position:0% +year of age and it's it's exactly that + + + align:start position:0% +year of age and it's it's exactly that +kind of thing also remember that if you + + align:start position:0% +kind of thing also remember that if you + + + align:start position:0% +kind of thing also remember that if you +saw John Leonard's talk yesterday he was + + align:start position:0% +saw John Leonard's talk yesterday he was + + + align:start position:0% +saw John Leonard's talk yesterday he was +the robotics guy who talked about + + align:start position:0% +the robotics guy who talked about + + + align:start position:0% +the robotics guy who talked about +self-driving cars and how you know + + align:start position:0% +self-driving cars and how you know + + + align:start position:0% +self-driving cars and how you know +there's certain gaps in what they can do + + align:start position:0% +there's certain gaps in what they can do + + + align:start position:0% +there's certain gaps in what they can do +despite that all the publicity like they + + align:start position:0% +despite that all the publicity like they + + + align:start position:0% +despite that all the publicity like they +can't turn left basically I'm in an + + align:start position:0% +can't turn left basically I'm in an + + + align:start position:0% +can't turn left basically I'm in an +unrestricted intersection because + + align:start position:0% +unrestricted intersection because + + + align:start position:0% +unrestricted intersection because +there's a certain kind of theory of mine + + align:start position:0% +there's a certain kind of theory of mine + + + align:start position:0% +there's a certain kind of theory of mine +in street scenes when when cars could be + + align:start position:0% +in street scenes when when cars could be + + + align:start position:0% +in street scenes when when cars could be +coming and people could be crossing or + + align:start position:0% +coming and people could be crossing or + + + align:start position:0% +coming and people could be crossing or +all those things about the police + + align:start position:0% +all those things about the police + + + align:start position:0% +all those things about the police +officers like this part of why this is + + align:start position:0% +officers like this part of why this is + + + align:start position:0% +officers like this part of why this is +so exciting to me and why I love that + + align:start position:0% +so exciting to me and why I love that + + + align:start position:0% +so exciting to me and why I love that +talk is because it's this is I think the + + align:start position:0% +talk is because it's this is I think the + + + align:start position:0% +talk is because it's this is I think the +same common common sense knowledge that + + align:start position:0% +same common common sense knowledge that + + + align:start position:0% +same common common sense knowledge that +if we can really figure out how to + + align:start position:0% +if we can really figure out how to + + + align:start position:0% +if we can really figure out how to +sure this reasoning about beliefs and + + align:start position:0% +sure this reasoning about beliefs and + + + align:start position:0% +sure this reasoning about beliefs and +desires in the limited context where + + align:start position:0% +desires in the limited context where + + + align:start position:0% +desires in the limited context where +desires are people moving around in + + align:start position:0% +desires are people moving around in + + + align:start position:0% +desires are people moving around in +space around us and the beliefs or who + + align:start position:0% +space around us and the beliefs or who + + + align:start position:0% +space around us and the beliefs or who +can see who right and a man who can see + + align:start position:0% +can see who right and a man who can see + + + align:start position:0% +can see who right and a man who can see +who can see who right a lot of in + + align:start position:0% +who can see who right a lot of in + + + align:start position:0% +who can see who right a lot of in +driving the art of making eye contact + + align:start position:0% +driving the art of making eye contact + + + align:start position:0% +driving the art of making eye contact +with other drivers or pedestrians is + + align:start position:0% +with other drivers or pedestrians is + + + align:start position:0% +with other drivers or pedestrians is +seeing that they can see you or that + + align:start position:0% +seeing that they can see you or that + + + align:start position:0% +seeing that they can see you or that +they can see what you can see and they + + align:start position:0% +they can see what you can see and they + + + align:start position:0% +they can see what you can see and they +can see you seeing them it doesn't have + + align:start position:0% +can see you seeing them it doesn't have + + + align:start position:0% +can see you seeing them it doesn't have +to be super deeply recursive but it's a + + align:start position:0% +to be super deeply recursive but it's a + + + align:start position:0% +to be super deeply recursive but it's a +couple of layers deep we don't have to + + align:start position:0% +couple of layers deep we don't have to + + + align:start position:0% +couple of layers deep we don't have to +think about it consciously but we have + + align:start position:0% +think about it consciously but we have + + + align:start position:0% +think about it consciously but we have +to be able to do it so that's the kind + + align:start position:0% +to be able to do it so that's the kind + + + align:start position:0% +to be able to do it so that's the kind +of core belief desire theory of mind + + align:start position:0% +of core belief desire theory of mind + + + align:start position:0% +of core belief desire theory of mind +reasoning and here's how we've tried to + + align:start position:0% +reasoning and here's how we've tried to + + + align:start position:0% +reasoning and here's how we've tried to +capture this this with probabilistic + + align:start position:0% +capture this this with probabilistic + + + align:start position:0% +capture this this with probabilistic +programs this is work that Chris Baker + + align:start position:0% +programs this is work that Chris Baker + + + align:start position:0% +programs this is work that Chris Baker +started doing a few years ago we've and + + align:start position:0% +started doing a few years ago we've and + + + align:start position:0% +started doing a few years ago we've and +a lot of it joint with Rebecca Saxe and + + align:start position:0% +a lot of it joint with Rebecca Saxe and + + + align:start position:0% +a lot of it joint with Rebecca Saxe and +also with some of it with Julian Hara + + align:start position:0% +also with some of it with Julian Hara + + + align:start position:0% +also with some of it with Julian Hara +Edinger and some of it with Tomer so + + align:start position:0% +Edinger and some of it with Tomer so + + + align:start position:0% +Edinger and some of it with Tomer so +there's a whole bunch of us who've been + + align:start position:0% +there's a whole bunch of us who've been + + + align:start position:0% +there's a whole bunch of us who've been +working on versions of this but I'll + + align:start position:0% +working on versions of this but I'll + + + align:start position:0% +working on versions of this but I'll +just show you one or two examples it's + + align:start position:0% +just show you one or two examples it's + + + align:start position:0% +just show you one or two examples it's +again here the the key the key programs + + align:start position:0% +again here the the key the key programs + + + align:start position:0% +again here the the key the key programs +here are not graphics or physics engines + + align:start position:0% +here are not graphics or physics engines + + + align:start position:0% +here are not graphics or physics engines +but planning engines and perception + + align:start position:0% +but planning engines and perception + + + align:start position:0% +but planning engines and perception +engines so very simple kinds of robotics + + align:start position:0% +engines so very simple kinds of robotics + + + align:start position:0% +engines so very simple kinds of robotics +programs far too simple in this forum to + + align:start position:0% +programs far too simple in this forum to + + + align:start position:0% +programs far too simple in this forum to +build a self-driving car or a humanoid + + align:start position:0% +build a self-driving car or a humanoid + + + align:start position:0% +build a self-driving car or a humanoid +robot but maybe the kind of thing that + + align:start position:0% +robot but maybe the kind of thing that + + + align:start position:0% +robot but maybe the kind of thing that +in game game robots like the zombie or + + align:start position:0% +in game game robots like the zombie or + + + align:start position:0% +in game game robots like the zombie or +the security guard in quake or something + + align:start position:0% +the security guard in quake or something + + + align:start position:0% +the security guard in quake or something +might do something like this um so + + align:start position:0% +might do something like this um so + + + align:start position:0% +might do something like this um so +planning basically just means it's a + + align:start position:0% +planning basically just means it's a + + + align:start position:0% +planning basically just means it's a +little bit more than on it sort of + + align:start position:0% +little bit more than on it sort of + + + align:start position:0% +little bit more than on it sort of +shortest path planning but it's + + align:start position:0% +shortest path planning but it's + + + align:start position:0% +shortest path planning but it's +basically like find a sequence of + + align:start position:0% +basically like find a sequence of + + + align:start position:0% +basically like find a sequence of +actions in in a simple world like moving + + align:start position:0% +actions in in a simple world like moving + + + align:start position:0% +actions in in a simple world like moving +around a 2d environment that maximizes + + align:start position:0% +around a 2d environment that maximizes + + + align:start position:0% +around a 2d environment that maximizes +your long run expected reward so there's + + align:start position:0% +your long run expected reward so there's + + + align:start position:0% +your long run expected reward so there's +a kind of utility theory or what Laura + + align:start position:0% +a kind of utility theory or what Laura + + + align:start position:0% +a kind of utility theory or what Laura +Schultz calls a naive utility calculus + + align:start position:0% +Schultz calls a naive utility calculus + + + align:start position:0% +Schultz calls a naive utility calculus +here a calculation of costs and benefits + + align:start position:0% +here a calculation of costs and benefits + + + align:start position:0% +here a calculation of costs and benefits +where in a sense you get a big reward a + + align:start position:0% +where in a sense you get a big reward a + + + align:start position:0% +where in a sense you get a big reward a +good positive utility for getting to + + align:start position:0% +good positive utility for getting to + + + align:start position:0% +good positive utility for getting to +your goal and a small cost for each + + align:start position:0% +your goal and a small cost for each + + + align:start position:0% +your goal and a small cost for each +action you take and if you and under the + + align:start position:0% +action you take and if you and under the + + + align:start position:0% +action you take and if you and under the +under that view then in some sense and + + align:start position:0% +under that view then in some sense and + + + align:start position:0% +under that view then in some sense and +some actions might be costlier than + + align:start position:0% +some actions might be costlier than + + + align:start position:0% +some actions might be costlier than +others something that Homer is looking + + align:start position:0% +others something that Homer is looking + + + align:start position:0% +others something that Homer is looking +at in infants and something the Julian + + align:start position:0% +at in infants and something the Julian + + + align:start position:0% +at in infants and something the Julian +higher ed and jurors looked at in older + + align:start position:0% +higher ed and jurors looked at in older + + + align:start position:0% +higher ed and jurors looked at in older +kids this understanding of that but this + + align:start position:0% +kids this understanding of that but this + + + align:start position:0% +kids this understanding of that but this +this sort of basic cost benefit + + align:start position:0% +this sort of basic cost benefit + + + align:start position:0% +this sort of basic cost benefit +trade-off that is going on whenever you + + align:start position:0% +trade-off that is going on whenever you + + + align:start position:0% +trade-off that is going on whenever you +move around in environment and decide + + align:start position:0% +move around in environment and decide + + + align:start position:0% +move around in environment and decide +well is it worthwhile to go all the way + + align:start position:0% +well is it worthwhile to go all the way + + + align:start position:0% +well is it worthwhile to go all the way +there or you know well I know I like the + + align:start position:0% +there or you know well I know I like the + + + align:start position:0% +there or you know well I know I like the +coffee up at pie-in-the-sky better than + + align:start position:0% +coffee up at pie-in-the-sky better than + + + align:start position:0% +coffee up at pie-in-the-sky better than +the coffee and the dining-hall here at + + align:start position:0% +the coffee and the dining-hall here at + + + align:start position:0% +the coffee and the dining-hall here at +Swope but you know to think about am I + + align:start position:0% +Swope but you know to think about am I + + + align:start position:0% +Swope but you know to think about am I +gonna be late to my lecture am I gonna + + align:start position:0% +gonna be late to my lecture am I gonna + + + align:start position:0% +gonna be late to my lecture am I gonna +be late to Nancy's lecture those are + + align:start position:0% +be late to Nancy's lecture those are + + + align:start position:0% +be late to Nancy's lecture those are +different costs both costs it's that + + align:start position:0% +different costs both costs it's that + + + align:start position:0% +different costs both costs it's that +kind of calculation okay so here let me + + align:start position:0% +kind of calculation okay so here let me + + + align:start position:0% +kind of calculation okay so here let me +get more concrete so here's an example + + align:start position:0% +get more concrete so here's an example + + + align:start position:0% +get more concrete so here's an example +of a experiment that Chris did a few + + align:start position:0% +of a experiment that Chris did a few + + + align:start position:0% +of a experiment that Chris did a few +years ago we're again it's like what you + + align:start position:0% +years ago we're again it's like what you + + + align:start position:0% +years ago we're again it's like what you +saw with the Heider and Simmel the + + align:start position:0% +saw with the Heider and Simmel the + + + align:start position:0% +saw with the Heider and Simmel the +squares and Trump and the triangles and + + align:start position:0% +squares and Trump and the triangles and + + + align:start position:0% +squares and Trump and the triangles and +circles or the south gain and chipra the + + align:start position:0% +circles or the south gain and chipra the + + + align:start position:0% +circles or the south gain and chipra the +red and blue balls chasing each other + + align:start position:0% +red and blue balls chasing each other + + + align:start position:0% +red and blue balls chasing each other +very simple stuff here you see an agent + + align:start position:0% +very simple stuff here you see an agent + + + align:start position:0% +very simple stuff here you see an agent +it's like an overhead view of a room 2d + + align:start position:0% +it's like an overhead view of a room 2d + + + align:start position:0% +it's like an overhead view of a room 2d +environment from the top the agents + + align:start position:0% +environment from the top the agents + + + align:start position:0% +environment from the top the agents +moving along some path there are three + + align:start position:0% +moving along some path there are three + + + align:start position:0% +moving along some path there are three +possible goals a B or C and then there's + + align:start position:0% +possible goals a B or C and then there's + + + align:start position:0% +possible goals a B or C and then there's +maybe some obstacles or constraints like + + align:start position:0% +maybe some obstacles or constraints like + + + align:start position:0% +maybe some obstacles or constraints like +a wall like like you saw in those movies + + align:start position:0% +a wall like like you saw in those movies + + + align:start position:0% +a wall like like you saw in those movies +maybe the wall has a hole that he can + + align:start position:0% +maybe the wall has a hole that he can + + + align:start position:0% +maybe the wall has a hole that he can +pass through maybe it doesn't and across + + align:start position:0% +pass through maybe it doesn't and across + + + align:start position:0% +pass through maybe it doesn't and across +different trials of the experiment just + + align:start position:0% +different trials of the experiment just + + + align:start position:0% +different trials of the experiment just +like in the physics stuff we vary all + + align:start position:0% +like in the physics stuff we vary all + + + align:start position:0% +like in the physics stuff we vary all +the block configurations and so on here + + align:start position:0% +the block configurations and so on here + + + align:start position:0% +the block configurations and so on here +we vary where the goals are we vary + + align:start position:0% +we vary where the goals are we vary + + + align:start position:0% +we vary where the goals are we vary +whether the wall has a hole or not we + + align:start position:0% +whether the wall has a hole or not we + + + align:start position:0% +whether the wall has a hole or not we +vary the agents paths on different + + align:start position:0% +vary the agents paths on different + + + align:start position:0% +vary the agents paths on different +trials we also stop it at different + + align:start position:0% +trials we also stop it at different + + + align:start position:0% +trials we also stop it at different +points because we're trying to see as + + align:start position:0% +points because we're trying to see as + + + align:start position:0% +points because we're trying to see as +you watch this agent move around action + + align:start position:0% +you watch this agent move around action + + + align:start position:0% +you watch this agent move around action +unfolds over time + + align:start position:0% +unfolds over time + + + align:start position:0% +unfolds over time +how do your guesses about his goal + + align:start position:0% +how do your guesses about his goal + + + align:start position:0% +how do your guesses about his goal +change over time and what you see that + + align:start position:0% +change over time and what you see that + + + align:start position:0% +change over time and what you see that +so these are just examples of a few of + + align:start position:0% +so these are just examples of a few of + + + align:start position:0% +so these are just examples of a few of +the few of the scenes and here what you + + align:start position:0% +the few of the scenes and here what you + + + align:start position:0% +the few of the scenes and here what you +see our examples of the data again this + + align:start position:0% +see our examples of the data again this + + + align:start position:0% +see our examples of the data again this +is the y-axis is the average human + + align:start position:0% +is the y-axis is the average human + + + align:start position:0% +is the y-axis is the average human +judgment red blue and green is + + align:start position:0% +judgment red blue and green is + + + align:start position:0% +judgment red blue and green is +color-coded to the goal they're just + + align:start position:0% +color-coded to the goal they're just + + + align:start position:0% +color-coded to the goal they're just +asked how likely do you think each of + + align:start position:0% +asked how likely do you think each of + + + align:start position:0% +asked how likely do you think each of +those three things is his goal and then + + align:start position:0% +those three things is his goal and then + + + align:start position:0% +those three things is his goal and then +here the x-axis is time so these are + + align:start position:0% +here the x-axis is time so these are + + + align:start position:0% +here the x-axis is time so these are +time steps that we that we ask at + + align:start position:0% +time steps that we that we ask at + + + align:start position:0% +time steps that we that we ask at +different points along the trajectory + + align:start position:0% +different points along the trajectory + + + align:start position:0% +different points along the trajectory +and what you can see is that people are + + align:start position:0% +and what you can see is that people are + + + align:start position:0% +and what you can see is that people are +making various systemic kinds of + + align:start position:0% +making various systemic kinds of + + + align:start position:0% +making various systemic kinds of +judgments sometimes they're not sure + + align:start position:0% +judgments sometimes they're not sure + + + align:start position:0% +judgments sometimes they're not sure +whether his goal is a or b but they know + + align:start position:0% +whether his goal is a or b but they know + + + align:start position:0% +whether his goal is a or b but they know +it's not C and then after a little while + + align:start position:0% +it's not C and then after a little while + + + align:start position:0% +it's not C and then after a little while +there's some some Keese that happens and + + align:start position:0% +there's some some Keese that happens and + + + align:start position:0% +there's some some Keese that happens and +now they're quite sure it's a and not B + + align:start position:0% +now they're quite sure it's a and not B + + + align:start position:0% +now they're quite sure it's a and not B +or they could change their mind you know + + align:start position:0% +or they could change their mind you know + + + align:start position:0% +or they could change their mind you know +here people were pretty sure it was + + align:start position:0% +here people were pretty sure it was + + + align:start position:0% +here people were pretty sure it was +either green or red but not blue and + + align:start position:0% +either green or red but not blue and + + + align:start position:0% +either green or red but not blue and +then there comes a point where it's + + align:start position:0% +then there comes a point where it's + + + align:start position:0% +then there comes a point where it's +surely not green but it might be blue or + + align:start position:0% +surely not green but it might be blue or + + + align:start position:0% +surely not green but it might be blue or +red oh no then it's red here they were + + align:start position:0% +red oh no then it's red here they were + + + align:start position:0% +red oh no then it's red here they were +pretty sure it was green then nope + + align:start position:0% +pretty sure it was green then nope + + + align:start position:0% +pretty sure it was green then nope +definitely not green and now I think + + align:start position:0% +definitely not green and now I think + + + align:start position:0% +definitely not green and now I think +it's red it was probably never blue okay + + align:start position:0% +it's red it was probably never blue okay + + + align:start position:0% +it's red it was probably never blue okay +and this really striking thing to us is + + align:start position:0% +and this really striking thing to us is + + + align:start position:0% +and this really striking thing to us is +how closely you can match + + align:start position:0% +how closely you can match + + + align:start position:0% +how closely you can match +those judgments with this very simple + + align:start position:0% +those judgments with this very simple + + + align:start position:0% +those judgments with this very simple +probabilistic planning program run in + + align:start position:0% +probabilistic planning program run in + + + align:start position:0% +probabilistic planning program run in +Reverse so we take again this simple + + align:start position:0% +Reverse so we take again this simple + + + align:start position:0% +Reverse so we take again this simple +planning program that just says + + align:start position:0% +planning program that just says + + + align:start position:0% +planning program that just says +basically try to just just kind of get + + align:start position:0% +basically try to just just kind of get + + + align:start position:0% +basically try to just just kind of get +as efficiently as possible to your goal + + align:start position:0% +as efficiently as possible to your goal + + + align:start position:0% +as efficiently as possible to your goal +I don't know if your goal is though I + + align:start position:0% +I don't know if your goal is though I + + + align:start position:0% +I don't know if your goal is though I +observe your actions that result from an + + align:start position:0% +observe your actions that result from an + + + align:start position:0% +observe your actions that result from an +efficient plan and I want to work + + align:start position:0% +efficient plan and I want to work + + + align:start position:0% +efficient plan and I want to work +backwards to say what do I think your + + align:start position:0% +backwards to say what do I think your + + + align:start position:0% +backwards to say what do I think your +goal is your desire the rewarding state + + align:start position:0% +goal is your desire the rewarding state + + + align:start position:0% +goal is your desire the rewarding state +and just doing that just basically + + align:start position:0% +and just doing that just basically + + + align:start position:0% +and just doing that just basically +perfectly predicts people's data I mean + + align:start position:0% +perfectly predicts people's data I mean + + + align:start position:0% +perfectly predicts people's data I mean +this is of all the mathematical models + + align:start position:0% +this is of all the mathematical models + + + align:start position:0% +this is of all the mathematical models +of behavior I've ever had a hand in + + align:start position:0% +of behavior I've ever had a hand in + + + align:start position:0% +of behavior I've ever had a hand in +building this one works the best + + align:start position:0% +building this one works the best + + + align:start position:0% +building this one works the best +it's really quite striking to me it was + + align:start position:0% +it's really quite striking to me it was + + + align:start position:0% +it's really quite striking to me it was +striking because I was I came in + + align:start position:0% +striking because I was I came in + + + align:start position:0% +striking because I was I came in +thinking this would be a high level very + + align:start position:0% +thinking this would be a high level very + + + align:start position:0% +thinking this would be a high level very +high level weird flaky hard to model + + align:start position:0% +high level weird flaky hard to model + + + align:start position:0% +high level weird flaky hard to model +thing um here's just one more example of + + align:start position:0% +thing um here's just one more example of + + + align:start position:0% +thing um here's just one more example of +one of these things which actually puts + + align:start position:0% +one of these things which actually puts + + + align:start position:0% +one of these things which actually puts +beliefs in there and not just desire so + + align:start position:0% +beliefs in there and not just desire so + + + align:start position:0% +beliefs in there and not just desire so +it's a key part of intuitive psychology + + align:start position:0% +it's a key part of intuitive psychology + + + align:start position:0% +it's a key part of intuitive psychology +that we do joint inference over beliefs + + align:start position:0% +that we do joint inference over beliefs + + + align:start position:0% +that we do joint inference over beliefs +and desires in this one here we assume + + align:start position:0% +and desires in this one here we assume + + + align:start position:0% +and desires in this one here we assume +that you the subject the agent who's + + align:start position:0% +that you the subject the agent who's + + + align:start position:0% +that you the subject the agent who's +moving around all of us have shared full + + align:start position:0% +moving around all of us have shared full + + + align:start position:0% +moving around all of us have shared full +knowledge of the world so we know where + + align:start position:0% +knowledge of the world so we know where + + + align:start position:0% +knowledge of the world so we know where +the objects are we know where the holes + + align:start position:0% +the objects are we know where the holes + + + align:start position:0% +the objects are we know where the holes +are there's none of this false belief + + align:start position:0% +are there's none of this false belief + + + align:start position:0% +are there's none of this false belief +like you think something is there when + + align:start position:0% +like you think something is there when + + + align:start position:0% +like you think something is there when +it isn't now here's some later work that + + align:start position:0% +it isn't now here's some later work that + + + align:start position:0% +it isn't now here's some later work that +Chris did where I'm what we call the + + align:start position:0% +Chris did where I'm what we call the + + + align:start position:0% +Chris did where I'm what we call the +food truck studies where here we add in + + align:start position:0% +food truck studies where here we add in + + + align:start position:0% +food truck studies where here we add in +some uncertainty about beliefs in + + align:start position:0% +some uncertainty about beliefs in + + + align:start position:0% +some uncertainty about beliefs in +addition to desires and it's easiest + + align:start position:0% +addition to desires and it's easiest + + + align:start position:0% +addition to desires and it's easiest +just to explain what this one example up + + align:start position:0% +just to explain what this one example up + + + align:start position:0% +just to explain what this one example up +there in the upper left so here and this + + align:start position:0% +there in the upper left so here and this + + + align:start position:0% +there in the upper left so here and this +like a lot of university campuses lunch + + align:start position:0% +like a lot of university campuses lunch + + + align:start position:0% +like a lot of university campuses lunch +is best found at food trucks which can + + align:start position:0% +is best found at food trucks which can + + + align:start position:0% +is best found at food trucks which can +park in different spots around campus + + align:start position:0% +park in different spots around campus + + + align:start position:0% +park in different spots around campus +here the yellow the two yellow squares + + align:start position:0% +here the yellow the two yellow squares + + + align:start position:0% +here the yellow the two yellow squares +show the two parking spots on this part + + align:start position:0% +show the two parking spots on this part + + + align:start position:0% +show the two parking spots on this part +of campus and there are several + + align:start position:0% +of campus and there are several + + + align:start position:0% +of campus and there are several +different trucks that can common park in + + align:start position:0% +different trucks that can common park in + + + align:start position:0% +different trucks that can common park in +different places on different days + + align:start position:0% +different places on different days + + + align:start position:0% +different places on different days +there's a Korean truck that's K there's + + align:start position:0% +there's a Korean truck that's K there's + + + align:start position:0% +there's a Korean truck that's K there's +a Lebanese truck that's L there's also + + align:start position:0% +a Lebanese truck that's L there's also + + + align:start position:0% +a Lebanese truck that's L there's also +other trucks like a Mexican truck but + + align:start position:0% +other trucks like a Mexican truck but + + + align:start position:0% +other trucks like a Mexican truck but +there's only two spots so if the Korean + + align:start position:0% +there's only two spots so if the Korean + + + align:start position:0% +there's only two spots so if the Korean +one parts there on the Lebanese one + + align:start position:0% +one parts there on the Lebanese one + + + align:start position:0% +one parts there on the Lebanese one +parts there the Mexican has to have go + + align:start position:0% +parts there the Mexican has to have go + + + align:start position:0% +parts there the Mexican has to have go +somewhere else or can't come there today + + align:start position:0% +somewhere else or can't come there today + + + align:start position:0% +somewhere else or can't come there today +and on some days the trucks park in + + align:start position:0% +and on some days the trucks park in + + + align:start position:0% +and on some days the trucks park in +different places and some or a spot + + align:start position:0% +different places and some or a spot + + + align:start position:0% +different places and some or a spot +could also be unoccupied the trucks + + align:start position:0% +could also be unoccupied the trucks + + + align:start position:0% +could also be unoccupied the trucks +could be elsewhere so look at what + + align:start position:0% +could be elsewhere so look at what + + + align:start position:0% +could be elsewhere so look at what +happens on this day our friendly grad + + align:start position:0% +happens on this day our friendly grad + + + align:start position:0% +happens on this day our friendly grad +student Harold + + align:start position:0% +student Harold + + + align:start position:0% +student Harold +comes out from his office here and + + align:start position:0% +comes out from his office here and + + + align:start position:0% +comes out from his office here and +importantly the way we model interesting + + align:start position:0% +importantly the way we model interesting + + + align:start position:0% +importantly the way we model interesting +notions of evolving belief is that now + + align:start position:0% +notions of evolving belief is that now + + + align:start position:0% +notions of evolving belief is that now +we've got that perception and inference + + align:start position:0% +we've got that perception and inference + + + align:start position:0% +we've got that perception and inference +arrow there so Harold forms his belief + + align:start position:0% +arrow there so Harold forms his belief + + + align:start position:0% +arrow there so Harold forms his belief +about what's where based on what he can + + align:start position:0% +about what's where based on what he can + + + align:start position:0% +about what's where based on what he can +see and it's just the simplest + + align:start position:0% +see and it's just the simplest + + + align:start position:0% +see and it's just the simplest +perception model just line-of-sight + + align:start position:0% +perception model just line-of-sight + + + align:start position:0% +perception model just line-of-sight +access + + align:start position:0% +access + + + align:start position:0% +access +we assume he can kind of see anything + + align:start position:0% +we assume he can kind of see anything + + + align:start position:0% +we assume he can kind of see anything +that's unobstructed in his line of sight + + align:start position:0% +that's unobstructed in his line of sight + + + align:start position:0% +that's unobstructed in his line of sight +so that means that when he comes out + + align:start position:0% +so that means that when he comes out + + + align:start position:0% +so that means that when he comes out +here he can see that there was the + + align:start position:0% +here he can see that there was the + + + align:start position:0% +here he can see that there was the +Korean truck here but he can't see this + + align:start position:0% +Korean truck here but he can't see this + + + align:start position:0% +Korean truck here but he can't see this +is a wall or a building he can't see + + align:start position:0% +is a wall or a building he can't see + + + align:start position:0% +is a wall or a building he can't see +what's on the other side of that okay so + + align:start position:0% +what's on the other side of that okay so + + + align:start position:0% +what's on the other side of that okay so +what does he do well he walks down here + + align:start position:0% +what does he do well he walks down here + + + align:start position:0% +what does he do well he walks down here +he goes past the Korean truck goes + + align:start position:0% +he goes past the Korean truck goes + + + align:start position:0% +he goes past the Korean truck goes +around the other side of the building + + align:start position:0% +around the other side of the building + + + align:start position:0% +around the other side of the building +now at this point his line of sight can + + align:start position:0% +now at this point his line of sight can + + + align:start position:0% +now at this point his line of sight can +gives him he can see that there's the + + align:start position:0% +gives him he can see that there's the + + + align:start position:0% +gives him he can see that there's the +Lebanese truck there he turns around and + + align:start position:0% +Lebanese truck there he turns around and + + + align:start position:0% +Lebanese truck there he turns around and +he goes back to the Korean truck so the + + align:start position:0% +he goes back to the Korean truck so the + + + align:start position:0% +he goes back to the Korean truck so the +question for you is what is his favorite + + align:start position:0% +question for you is what is his favorite + + + align:start position:0% +question for you is what is his favorite +truck is it Korean Lebanese or Mexican + + align:start position:0% +truck is it Korean Lebanese or Mexican + + + align:start position:0% +truck is it Korean Lebanese or Mexican +Mexican yeah it doesn't sound very hard + + align:start position:0% +Mexican yeah it doesn't sound very hard + + + align:start position:0% +Mexican yeah it doesn't sound very hard +to figure that out but it's quite + + align:start position:0% +to figure that out but it's quite + + + align:start position:0% +to figure that out but it's quite +interesting because the Mexican one + + align:start position:0% +interesting because the Mexican one + + + align:start position:0% +interesting because the Mexican one +isn't even in the scene right the most + + align:start position:0% +isn't even in the scene right the most + + + align:start position:0% +isn't even in the scene right the most +basic kind of goal goal recognition and + + align:start position:0% +basic kind of goal goal recognition and + + + align:start position:0% +basic kind of goal goal recognition and +this again cuts right to the heart of + + align:start position:0% +this again cuts right to the heart of + + + align:start position:0% +this again cuts right to the heart of +the differencing recognition and + + align:start position:0% +the differencing recognition and + + + align:start position:0% +the differencing recognition and +explanation right there's been a lot of + + align:start position:0% +explanation right there's been a lot of + + + align:start position:0% +explanation right there's been a lot of +progress in machine vision systems for + + align:start position:0% +progress in machine vision systems for + + + align:start position:0% +progress in machine vision systems for +action understanding action recognition + + align:start position:0% +action understanding action recognition + + + align:start position:0% +action understanding action recognition +and so on and they do things like you + + align:start position:0% +and so on and they do things like you + + + align:start position:0% +and so on and they do things like you +know for example they take video and the + + align:start position:0% +know for example they take video and the + + + align:start position:0% +know for example they take video and the +best cue that somebody wants something + + align:start position:0% +best cue that somebody wants something + + + align:start position:0% +best cue that somebody wants something +is if they reach for it or move towards + + align:start position:0% +is if they reach for it or move towards + + + align:start position:0% +is if they reach for it or move towards +it and that's certainly what was going + + align:start position:0% +it and that's certainly what was going + + + align:start position:0% +it and that's certainly what was going +on here right in all of these scenes + + align:start position:0% +on here right in all of these scenes + + + align:start position:0% +on here right in all of these scenes +your best inference about what the guy's + + align:start position:0% +your best inference about what the guy's + + + align:start position:0% +your best inference about what the guy's +goal is is which thing is he moving + + align:start position:0% +goal is is which thing is he moving + + + align:start position:0% +goal is is which thing is he moving +towards and it's just it's just subtle + + align:start position:0% +towards and it's just it's just subtle + + + align:start position:0% +towards and it's just it's just subtle +to parse out the relative degrees of + + align:start position:0% +to parse out the relative degrees of + + + align:start position:0% +to parse out the relative degrees of +confidence when there's a complex + + align:start position:0% +confidence when there's a complex + + + align:start position:0% +confidence when there's a complex +environment with constraints but in + + align:start position:0% +environment with constraints but in + + + align:start position:0% +environment with constraints but in +every case by the end it's clear he's + + align:start position:0% +every case by the end it's clear he's + + + align:start position:0% +every case by the end it's clear he's +going for one thing and the thing he is + + align:start position:0% +going for one thing and the thing he is + + + align:start position:0% +going for one thing and the thing he is +moving towards is the thing he wants but + + align:start position:0% +moving towards is the thing he wants but + + + align:start position:0% +moving towards is the thing he wants but +here you have no trouble realizing that + + align:start position:0% +here you have no trouble realizing that + + + align:start position:0% +here you have no trouble realizing that +his goal is something that isn't even + + align:start position:0% +his goal is something that isn't even + + + align:start position:0% +his goal is something that isn't even +present in the scene yet he's still + + align:start position:0% +present in the scene yet he's still + + + align:start position:0% +present in the scene yet he's still +moving towards it in a sense he's moving + + align:start position:0% +moving towards it in a sense he's moving + + + align:start position:0% +moving towards it in a sense he's moving +towards his mental representation of it + + align:start position:0% +towards his mental representation of it + + + align:start position:0% +towards his mental representation of it +right he's moving towards the Mexican + + align:start position:0% +right he's moving towards the Mexican + + + align:start position:0% +right he's moving towards the Mexican +truck in his mind's model and that's him + + align:start position:0% +truck in his mind's model and that's him + + + align:start position:0% +truck in his mind's model and that's him +explaining the data he sees right for + + align:start position:0% +explaining the data he sees right for + + + align:start position:0% +explaining the data he sees right for +some reason he must have had maybe a + + align:start position:0% +some reason he must have had maybe a + + + align:start position:0% +some reason he must have had maybe a +prior belief that the Mexican truck + + align:start position:0% +prior belief that the Mexican truck + + + align:start position:0% +prior belief that the Mexican truck +would be there so he formed a plan to go + + align:start position:0% +would be there so he formed a plan to go + + + align:start position:0% +would be there so he formed a plan to go +there and in fact we can ask people not + + align:start position:0% +there and in fact we can ask people not + + + align:start position:0% +there and in fact we can ask people not +only which truck does he like this is + + align:start position:0% +only which truck does he like this is + + + align:start position:0% +only which truck does he like this is +Mexican truck that's what people say and + + align:start position:0% +Mexican truck that's what people say and + + + align:start position:0% +Mexican truck that's what people say and +here's the model but we also asked them + + align:start position:0% +here's the model but we also asked them + + + align:start position:0% +here's the model but we also asked them +a belief inference we say I'm prior to + + align:start position:0% +a belief inference we say I'm prior to + + + align:start position:0% +a belief inference we say I'm prior to +setting out what did Harold think was on + + align:start position:0% +setting out what did Harold think was on + + + align:start position:0% +setting out what did Harold think was on +the other side did he what was parked on + + align:start position:0% +the other side did he what was parked on + + + align:start position:0% +the other side did he what was parked on +the other spot that he couldn't see did + + align:start position:0% +the other spot that he couldn't see did + + + align:start position:0% +the other spot that he couldn't see did +he think it was Lebanese Mexican or a + + align:start position:0% +he think it was Lebanese Mexican or a + + + align:start position:0% +he think it was Lebanese Mexican or a +neither and we asked a degree of belief + + align:start position:0% +neither and we asked a degree of belief + + + align:start position:0% +neither and we asked a degree of belief +so you could say he had no idea but + + align:start position:0% +so you could say he had no idea but + + + align:start position:0% +so you could say he had no idea but +interestingly people say he probably + + align:start position:0% +interestingly people say he probably + + + align:start position:0% +interestingly people say he probably +thought it was Mexican + + align:start position:0% +thought it was Mexican + + + align:start position:0% +thought it was Mexican +because how else could you explain what + + align:start position:0% +because how else could you explain what + + + align:start position:0% +because how else could you explain what +he's doing right so I mean I think this + + align:start position:0% +he's doing right so I mean I think this + + + align:start position:0% +he's doing right so I mean I think this +is if I had to point to just one example + + align:start position:0% +is if I had to point to just one example + + + align:start position:0% +is if I had to point to just one example +of cognition as explanation it's this + + align:start position:0% +of cognition as explanation it's this + + + align:start position:0% +of cognition as explanation it's this +right he's the only sensible way and + + align:start position:0% +right he's the only sensible way and + + + align:start position:0% +right he's the only sensible way and +it's a very intuitive and compelling way + + align:start position:0% +it's a very intuitive and compelling way + + + align:start position:0% +it's a very intuitive and compelling way +to explain why did he go the way he did + + align:start position:0% +to explain why did he go the way he did + + + align:start position:0% +to explain why did he go the way he did +and then turn around just when he did + + align:start position:0% +and then turn around just when he did + + + align:start position:0% +and then turn around just when he did +and wind up just where he did is this + + align:start position:0% +and wind up just where he did is this + + + align:start position:0% +and wind up just where he did is this +set of six inferences basically that his + + align:start position:0% +set of six inferences basically that his + + + align:start position:0% +set of six inferences basically that his +favorite is Mexican his second favorite + + align:start position:0% +favorite is Mexican his second favorite + + + align:start position:0% +favorite is Mexican his second favorite +is Korea and that's also important his + + align:start position:0% +is Korea and that's also important his + + + align:start position:0% +is Korea and that's also important his +least favorite is Lebanese and he + + align:start position:0% +least favorite is Lebanese and he + + + align:start position:0% +least favorite is Lebanese and he +thought that Mexican was there which is + + align:start position:0% +thought that Mexican was there which is + + + align:start position:0% +thought that Mexican was there which is +why it was worthwhile to go and check at + + align:start position:0% +why it was worthwhile to go and check at + + + align:start position:0% +why it was worthwhile to go and check at +least he thought it was likely he wasn't + + align:start position:0% +least he thought it was likely he wasn't + + + align:start position:0% +least he thought it was likely he wasn't +sure it's right notice it's not very + + align:start position:0% +sure it's right notice it's not very + + + align:start position:0% +sure it's right notice it's not very +high but it was more likely than the + + align:start position:0% +high but it was more likely than the + + + align:start position:0% +high but it was more likely than the +other possibilities because of course if + + align:start position:0% +other possibilities because of course if + + + align:start position:0% +other possibilities because of course if +he thought if he was quite sure it was + + align:start position:0% +he thought if he was quite sure it was + + + align:start position:0% +he thought if he was quite sure it was +Lebanese well he wouldn't have bothered + + align:start position:0% +Lebanese well he wouldn't have bothered + + + align:start position:0% +Lebanese well he wouldn't have bothered +to go around there and in fact you do + + align:start position:0% +to go around there and in fact you do + + + align:start position:0% +to go around there and in fact you do +see that so you have ones I guess I + + align:start position:0% +see that so you have ones I guess I + + + align:start position:0% +see that so you have ones I guess I +don't have them here but there are + + align:start position:0% +don't have them here but there are + + + align:start position:0% +don't have them here but there are +scenes where he just goes straight here + + align:start position:0% +scenes where he just goes straight here + + + align:start position:0% +scenes where he just goes straight here +and then you know that's consistent with + + align:start position:0% +and then you know that's consistent with + + + align:start position:0% +and then you know that's consistent with +him thinking Kausalya was Lebanese and + + align:start position:0% +him thinking Kausalya was Lebanese and + + + align:start position:0% +him thinking Kausalya was Lebanese and +if he thought nothing was there well + + align:start position:0% +if he thought nothing was there well + + + align:start position:0% +if he thought nothing was there well +again he wouldn't have gone to check all + + align:start position:0% +again he wouldn't have gone to check all + + + align:start position:0% +again he wouldn't have gone to check all +right and again this model is extremely + + align:start position:0% +right and again this model is extremely + + + align:start position:0% +right and again this model is extremely +quantitatively predictive of people's + + align:start position:0% +quantitatively predictive of people's + + + align:start position:0% +quantitatively predictive of people's +judgments about both desires and beliefs + + align:start position:0% +judgments about both desires and beliefs + + + align:start position:0% +judgments about both desires and beliefs +you can read in some of Battaglia's + + align:start position:0% +you can read in some of Battaglia's + + + align:start position:0% +you can read in some of Battaglia's +papers ways in which you take the very + + align:start position:0% +papers ways in which you take the very + + + align:start position:0% +papers ways in which you take the very +same physics engine and use it for all + + align:start position:0% +same physics engine and use it for all + + + align:start position:0% +same physics engine and use it for all +these different tasks including sort of + + align:start position:0% +these different tasks including sort of + + + align:start position:0% +these different tasks including sort of +slightly weird ones like these tasks if + + align:start position:0% +slightly weird ones like these tasks if + + + align:start position:0% +slightly weird ones like these tasks if +if you know if you bump the table are + + align:start position:0% +if you know if you bump the table are + + + align:start position:0% +if you know if you bump the table are +you more likely to knock off red blocks + + align:start position:0% +you more likely to knock off red blocks + + + align:start position:0% +you more likely to knock off red blocks +or yellow blocks you know not a task you + + align:start position:0% +or yellow blocks you know not a task you + + + align:start position:0% +or yellow blocks you know not a task you +have you ever got in the end-to-end + + align:start position:0% +have you ever got in the end-to-end + + + align:start position:0% +have you ever got in the end-to-end +training on right but an example of the + + align:start position:0% +training on right but an example of the + + + align:start position:0% +training on right but an example of the +the compositionality of your model and + + align:start position:0% +the compositionality of your model and + + + align:start position:0% +the compositionality of your model and +your task right somebody asked me this + + align:start position:0% +your task right somebody asked me this + + + align:start position:0% +your task right somebody asked me this +during lunch and I think it is a key + + align:start position:0% +during lunch and I think it is a key + + + align:start position:0% +during lunch and I think it is a key +point to make about compositionality one + + align:start position:0% +point to make about compositionality one + + + align:start position:0% +point to make about compositionality one +of the key ways in which composite + + align:start position:0% +of the key ways in which composite + + + align:start position:0% +of the key ways in which composite +compositionality works in this view of + + align:start position:0% +compositionality works in this view of + + + align:start position:0% +compositionality works in this view of +the mind as opposed to the + + align:start position:0% +the mind as opposed to the + + + align:start position:0% +the mind as opposed to the +pattern-recognition view or the way + + align:start position:0% +pattern-recognition view or the way + + + align:start position:0% +pattern-recognition view or the way +let's say like a deep Q Network works + + align:start position:0% +let's say like a deep Q Network works + + + align:start position:0% +let's say like a deep Q Network works +I'm just ways of getting a very flexible + + align:start position:0% +I'm just ways of getting a very flexible + + + align:start position:0% +I'm just ways of getting a very flexible +repertoire of inferences from composing + + align:start position:0% +repertoire of inferences from composing + + + align:start position:0% +repertoire of inferences from composing +pieces without having to train + + align:start position:0% +pieces without having to train + + + align:start position:0% +pieces without having to train +specifically for it right is that if you + + align:start position:0% +specifically for it right is that if you + + + align:start position:0% +specifically for it right is that if you +if you have a physics engine you can + + align:start position:0% +if you have a physics engine you can + + + align:start position:0% +if you have a physics engine you can +simulate the physical world you can you + + align:start position:0% +simulate the physical world you can you + + + align:start position:0% +simulate the physical world you can you +can answer questions that you've never + + align:start position:0% +can answer questions that you've never + + + align:start position:0% +can answer questions that you've never +gotten any training at all to solve so + + align:start position:0% +gotten any training at all to solve so + + + align:start position:0% +gotten any training at all to solve so +in this experiment here we ask people if + + align:start position:0% +in this experiment here we ask people if + + + align:start position:0% +in this experiment here we ask people if +you bump the table hard enough to knock + + align:start position:0% +you bump the table hard enough to knock + + + align:start position:0% +you bump the table hard enough to knock +some of the blocks onto the floor is it + + align:start position:0% +some of the blocks onto the floor is it + + + align:start position:0% +some of the blocks onto the floor is it +more likely to be red or yellow blocks + + align:start position:0% +more likely to be red or yellow blocks + + + align:start position:0% +more likely to be red or yellow blocks +questions of will this tower fall over + + align:start position:0% +questions of will this tower fall over + + + align:start position:0% +questions of will this tower fall over +which we've made a lot of judgments + + align:start position:0% +which we've made a lot of judgments + + + align:start position:0% +which we've made a lot of judgments +that's or you've never made that kind of + + align:start position:0% +that's or you've never made that kind of + + + align:start position:0% +that's or you've never made that kind of +judgment or it's a slightly weird one + + align:start position:0% +judgment or it's a slightly weird one + + + align:start position:0% +judgment or it's a slightly weird one +right but you have no trouble making it + + align:start position:0% +right but you have no trouble making it + + + align:start position:0% +right but you have no trouble making it +and for many different configurations of + + align:start position:0% +and for many different configurations of + + + align:start position:0% +and for many different configurations of +blocks + + align:start position:0% +blocks + + + align:start position:0% +blocks +you make various create a different and + + align:start position:0% +you make various create a different and + + + align:start position:0% +you make various create a different and +the model catches it perfectly with no + + align:start position:0% +the model catches it perfectly with no + + + align:start position:0% +the model catches it perfectly with no +extra stuff put in you just you just + + align:start position:0% +extra stuff put in you just you just + + + align:start position:0% +extra stuff put in you just you just +take the same model and you ask it a + + align:start position:0% +take the same model and you ask it a + + + align:start position:0% +take the same model and you ask it a +different question + + align:start position:0% +different question + + + align:start position:0% +different question +so if our dream is to build a I can + + align:start position:0% +so if our dream is to build a I can + + + align:start position:0% +so if our dream is to build a I can +answer questions for example which a lot + + align:start position:0% +answer questions for example which a lot + + + align:start position:0% +answer questions for example which a lot +of people's dream is I think there's + + align:start position:0% +of people's dream is I think there's + + + align:start position:0% +of people's dream is I think there's +really no compelling alternative to + + align:start position:0% +really no compelling alternative to + + + align:start position:0% +really no compelling alternative to +something like this that you build a + + align:start position:0% +something like this that you build a + + + align:start position:0% +something like this that you build a +model that you can ask all the questions + + align:start position:0% +model that you can ask all the questions + + + align:start position:0% +model that you can ask all the questions +of that you'd want to ask and in this + + align:start position:0% +of that you'd want to ask and in this + + + align:start position:0% +of that you'd want to ask and in this +limited domain again it's just our Atari + + align:start position:0% +limited domain again it's just our Atari + + + align:start position:0% +limited domain again it's just our Atari +right in this limited omein of reasoning + + align:start position:0% +right in this limited omein of reasoning + + + align:start position:0% +right in this limited omein of reasoning +about the physics of blocks it's really + + align:start position:0% +about the physics of blocks it's really + + + align:start position:0% +about the physics of blocks it's really +critical what this physics engine is + + align:start position:0% +critical what this physics engine is + + + align:start position:0% +critical what this physics engine is +able to do ends of questions it can + + align:start position:0% +able to do ends of questions it can + + + align:start position:0% +able to do ends of questions it can +reason about things with different + + align:start position:0% +reason about things with different + + + align:start position:0% +reason about things with different +masses it can make guesses about the + + align:start position:0% +masses it can make guesses about the + + + align:start position:0% +masses it can make guesses about the +masses you can make some of the objects + + align:start position:0% +masses you can make some of the objects + + + align:start position:0% +masses you can make some of the objects +bigger or smaller you can add attached + + align:start position:0% +bigger or smaller you can add attached + + + align:start position:0% +bigger or smaller you can add attached +constraints like fences to the table and + + align:start position:0% +constraints like fences to the table and + + + align:start position:0% +constraints like fences to the table and +the same model without any fundamental + + align:start position:0% +the same model without any fundamental + + + align:start position:0% +the same model without any fundamental +change can answer all these questions so + + align:start position:0% +change can answer all these questions so + + + align:start position:0% +change can answer all these questions so +it doesn't have to be retrained because + + align:start position:0% +it doesn't have to be retrained because + + + align:start position:0% +it doesn't have to be retrained because +there's basically no training right it's + + align:start position:0% +there's basically no training right it's + + + align:start position:0% +there's basically no training right it's +just reasoning but if we want to + + align:start position:0% +just reasoning but if we want to + + + align:start position:0% +just reasoning but if we want to +understand how learning works we first + + align:start position:0% +understand how learning works we first + + + align:start position:0% +understand how learning works we first +have to understand what's learned I + + align:start position:0% +have to understand what's learned I + + + align:start position:0% +have to understand what's learned I +think right now we're only at the point + + align:start position:0% +think right now we're only at the point + + + align:start position:0% +think right now we're only at the point +where we're starting to really have a + + align:start position:0% +where we're starting to really have a + + + align:start position:0% +where we're starting to really have a +sense of what are these mental models of + + align:start position:0% +sense of what are these mental models of + + + align:start position:0% +sense of what are these mental models of +the physical physical world and + + align:start position:0% +the physical physical world and + + + align:start position:0% +the physical physical world and +intentional action these public programs + + align:start position:0% +intentional action these public programs + + + align:start position:0% +intentional action these public programs +that even young children are are using + + align:start position:0% +that even young children are are using + + + align:start position:0% +that even young children are are using +to reason about the world and then it's + + align:start position:0% +to reason about the world and then it's + + + align:start position:0% +to reason about the world and then it's +a separate question how those are built + + align:start position:0% +a separate question how those are built + + + align:start position:0% +a separate question how those are built +up right through some combination of you + + align:start position:0% +up right through some combination of you + + + align:start position:0% +up right through some combination of you +know scientific discovery sorts of + + align:start position:0% +know scientific discovery sorts of + + + align:start position:0% +know scientific discovery sorts of +processes and and the evolution so + + align:start position:0% +processes and and the evolution so + + + align:start position:0% +processes and and the evolution so +here's the story and I most of what I + + align:start position:0% +here's the story and I most of what I + + + align:start position:0% +here's the story and I most of what I +want to tell you but the rest you'll get + + align:start position:0% +want to tell you but the rest you'll get + + + align:start position:0% +want to tell you but the rest you'll get +to hear some of it you'll get to hear + + align:start position:0% +to hear some of it you'll get to hear + + + align:start position:0% +to hear some of it you'll get to hear +next week from both our developmental + + align:start position:0% +next week from both our developmental + + + align:start position:0% +next week from both our developmental +colleagues and from me and Tomer on more + + align:start position:0% +colleagues and from me and Tomer on more + + + align:start position:0% +colleagues and from me and Tomer on more +on the computational side but actually + + align:start position:0% +on the computational side but actually + + + align:start position:0% +on the computational side but actually +the most interesting part we just don't + + align:start position:0% +the most interesting part we just don't + + + align:start position:0% +the most interesting part we just don't +know yet so we hope you will actually + + align:start position:0% +know yet so we hope you will actually + + + align:start position:0% +know yet so we hope you will actually +write that next chapter of the story but + + align:start position:0% +write that next chapter of the story but + + + align:start position:0% +write that next chapter of the story but +here's the here's the outlines of we're + + align:start position:0% +here's the here's the outlines of we're + + + align:start position:0% +here's the here's the outlines of we're +just currently see things right we think + + align:start position:0% +just currently see things right we think + + + align:start position:0% +just currently see things right we think +that we have a good target for what is + + align:start position:0% +that we have a good target for what is + + + align:start position:0% +that we have a good target for what is +really the core of human intelligence + + align:start position:0% +really the core of human intelligence + + + align:start position:0% +really the core of human intelligence +what makes us so smart in terms of these + + align:start position:0% +what makes us so smart in terms of these + + + align:start position:0% +what makes us so smart in terms of these +ideas of both what we start with look + + align:start position:0% +ideas of both what we start with look + + + align:start position:0% +ideas of both what we start with look +this common sense core physics and + + align:start position:0% +this common sense core physics and + + + align:start position:0% +this common sense core physics and +psychology and how those things grow + + align:start position:0% +psychology and how those things grow + + + align:start position:0% +psychology and how those things grow +these are how you know what are the that + + align:start position:0% +these are how you know what are the that + + + align:start position:0% +these are how you know what are the that +the learning mechanisms that I've just + + align:start position:0% +the learning mechanisms that I've just + + + align:start position:0% +the learning mechanisms that I've just +just again more next week on the sort of + + align:start position:0% +just again more next week on the sort of + + + align:start position:0% +just again more next week on the sort of +science like mechanisms of hypothesis + + align:start position:0% +science like mechanisms of hypothesis + + + align:start position:0% +science like mechanisms of hypothesis +formation experiment testing plague + + align:start position:0% +formation experiment testing plague + + + align:start position:0% +formation experiment testing plague +exploration that you can use to build + + align:start position:0% +exploration that you can use to build + + + align:start position:0% +exploration that you can use to build +these intuitive theories much like + + align:start position:0% +these intuitive theories much like + + + align:start position:0% +these intuitive theories much like +scientists build their + + align:start position:0% +scientists build their + + + align:start position:0% +scientists build their +theories and that we're starting on the + + align:start position:0% +theories and that we're starting on the + + + align:start position:0% +theories and that we're starting on the +engineering side to have tools to + + align:start position:0% +engineering side to have tools to + + + align:start position:0% +engineering side to have tools to +capture this both to capture the + + align:start position:0% +capture this both to capture the + + + align:start position:0% +capture this both to capture the +knowledge and how it might grow use of + + align:start position:0% +knowledge and how it might grow use of + + + align:start position:0% +knowledge and how it might grow use of +probabilistic programs and things that + + align:start position:0% +probabilistic programs and things that + + + align:start position:0% +probabilistic programs and things that +sometimes go by the name of program + + align:start position:0% +sometimes go by the name of program + + + align:start position:0% +sometimes go by the name of program +induction or program synthesis or if you + + align:start position:0% +induction or program synthesis or if you + + + align:start position:0% +induction or program synthesis or if you +like hierarchical Bayes on programs that + + align:start position:0% +like hierarchical Bayes on programs that + + + align:start position:0% +like hierarchical Bayes on programs that +generate other programs where the search + + align:start position:0% +generate other programs where the search + + + align:start position:0% +generate other programs where the search +through for a good program is like the + + align:start position:0% +through for a good program is like the + + + align:start position:0% +through for a good program is like the +inference of a program that best + + align:start position:0% +inference of a program that best + + + align:start position:0% +inference of a program that best +explains the data as generated from a + + align:start position:0% +explains the data as generated from a + + + align:start position:0% +explains the data as generated from a +prior that's a higher level program if + + align:start position:0% +prior that's a higher level program if + + + align:start position:0% +prior that's a higher level program if +you go to the tutorial from Tomer you'll + + align:start position:0% +you go to the tutorial from Tomer you'll + + + align:start position:0% +you go to the tutorial from Tomer you'll +actually see building blocks like you + + align:start position:0% +actually see building blocks like you + + + align:start position:0% +actually see building blocks like you +can write church programs that will do + + align:start position:0% +can write church programs that will do + + + align:start position:0% +can write church programs that will do +something like that and you will see + + align:start position:0% +something like that and you will see + + + align:start position:0% +something like that and you will see +more of that next time but the key is + + align:start position:0% +more of that next time but the key is + + + align:start position:0% +more of that next time but the key is +that we have a language now which which + + align:start position:0% +that we have a language now which which + + + align:start position:0% +that we have a language now which which +keep you know keeps building the + + align:start position:0% +keep you know keeps building the + + + align:start position:0% +keep you know keeps building the +different ingredients that we think we + + align:start position:0% +different ingredients that we think we + + + align:start position:0% +different ingredients that we think we +need on the one hand we've gone from + + align:start position:0% +need on the one hand we've gone from + + + align:start position:0% +need on the one hand we've gone from +thinking that we need something like + + align:start position:0% +thinking that we need something like + + + align:start position:0% +thinking that we need something like +probablistic generative models which + + align:start position:0% +probablistic generative models which + + + align:start position:0% +probablistic generative models which +many people will agree with to recognize + + align:start position:0% +many people will agree with to recognize + + + align:start position:0% +many people will agree with to recognize +that not only do they have to be + + align:start position:0% +that not only do they have to be + + + align:start position:0% +that not only do they have to be +generative they have to be causal and + + align:start position:0% +generative they have to be causal and + + + align:start position:0% +generative they have to be causal and +compositional and they have to have this + + align:start position:0% +compositional and they have to have this + + + align:start position:0% +compositional and they have to have this +fine-grained compositional structure + + align:start position:0% +fine-grained compositional structure + + + align:start position:0% +fine-grained compositional structure +needed to capture the real stuff of the + + align:start position:0% +needed to capture the real stuff of the + + + align:start position:0% +needed to capture the real stuff of the +world not graphs but something more like + + align:start position:0% +world not graphs but something more like + + + align:start position:0% +world not graphs but something more like +equations that capture graphics or + + align:start position:0% +equations that capture graphics or + + + align:start position:0% +equations that capture graphics or +physics or planning of course that's not + + align:start position:0% +physics or planning of course that's not + + + align:start position:0% +physics or planning of course that's not +all right I mean as I tried to gesture + + align:start position:0% +all right I mean as I tried to gesture + + + align:start position:0% +all right I mean as I tried to gesture +at we need also ways to make these + + align:start position:0% +at we need also ways to make these + + + align:start position:0% +at we need also ways to make these +things work very very well that's the + + align:start position:0% +things work very very well that's the + + + align:start position:0% +things work very very well that's the +you know there might be a place in this + + align:start position:0% +you know there might be a place in this + + + align:start position:0% +you know there might be a place in this +picture for something like neural + + align:start position:0% +picture for something like neural + + + align:start position:0% +picture for something like neural +networks or some kind of you know + + align:start position:0% +networks or some kind of you know + + + align:start position:0% +networks or some kind of you know +alternative pros and con approach based + + align:start position:0% +alternative pros and con approach based + + + align:start position:0% +alternative pros and con approach based +on pattern recognition but these are + + align:start position:0% +on pattern recognition but these are + + + align:start position:0% +on pattern recognition but these are +just a number of the ways which I think + + align:start position:0% +just a number of the ways which I think + + + align:start position:0% +just a number of the ways which I think +we need to think about going forward we + + align:start position:0% +we need to think about going forward we + + + align:start position:0% +we need to think about going forward we +need to take the idea of both at the + + align:start position:0% +need to take the idea of both at the + + + align:start position:0% +need to take the idea of both at the +brain as a pattern recognition engine + + align:start position:0% +brain as a pattern recognition engine + + + align:start position:0% +brain as a pattern recognition engine +seriously and the idea of the brain as a + + align:start position:0% +seriously and the idea of the brain as a + + + align:start position:0% +seriously and the idea of the brain as a +modeling or explanation engine seriously + + align:start position:0% +modeling or explanation engine seriously + + + align:start position:0% +modeling or explanation engine seriously +we're excited because we now have tools + + align:start position:0% +we're excited because we now have tools + + + align:start position:0% +we're excited because we now have tools +to model modeling engines and maybe to + + align:start position:0% +to model modeling engines and maybe to + + + align:start position:0% +to model modeling engines and maybe to +model how pattern recognition engines + + align:start position:0% +model how pattern recognition engines + + + align:start position:0% +model how pattern recognition engines +and modeling engines might interact but + + align:start position:0% +and modeling engines might interact but + + + align:start position:0% +and modeling engines might interact but +really again the great challenges here + + align:start position:0% +really again the great challenges here + + + align:start position:0% +really again the great challenges here +are really very much in our future not + + align:start position:0% +are really very much in our future not + + + align:start position:0% +are really very much in our future not +the unforeseeable future but the + + align:start position:0% +the unforeseeable future but the + + + align:start position:0% +the unforeseeable future but the +foreseeable ones so help us work on it + + align:start position:0% + + + + align:start position:0% + +you \ No newline at end of file diff --git a/eJqreNZPS64.txt b/eJqreNZPS64.txt new file mode 100644 index 0000000000000000000000000000000000000000..c317b3655b3db79ce8733b4eb7ca5fc7ec5f3c68 --- /dev/null +++ b/eJqreNZPS64.txt @@ -0,0 +1,955 @@ +align:start position:0% + +hi and welcome today we're going to do a + + align:start position:0% +hi and welcome today we're going to do a + + + align:start position:0% +hi and welcome today we're going to do a +problem about + + align:start position:0% +problem about + + + align:start position:0% +problem about +where's approximations here's the + + align:start position:0% +where's approximations here's the + + + align:start position:0% +where's approximations here's the +question find the quadratic equation + + align:start position:0% +question find the quadratic equation + + + align:start position:0% +question find the quadratic equation +through the origin + + align:start position:0% +through the origin + + + align:start position:0% +through the origin +that is a best fit for these three + + align:start position:0% +that is a best fit for these three + + + align:start position:0% +that is a best fit for these three +points 1 1 2 5 and negative 1 negative 2 + + align:start position:0% +points 1 1 2 5 and negative 1 negative 2 + + + align:start position:0% +points 1 1 2 5 and negative 1 negative 2 +I'll give you a minute to work that out + + align:start position:0% +I'll give you a minute to work that out + + + align:start position:0% +I'll give you a minute to work that out +on your own uh you can hit the pause + + align:start position:0% +on your own uh you can hit the pause + + + align:start position:0% +on your own uh you can hit the pause +button now and uh we'll be back in a + + align:start position:0% +button now and uh we'll be back in a + + + align:start position:0% +button now and uh we'll be back in a +minute to work the problem out together + + align:start position:0% + + + + align:start position:0% + +okay and were we're back so what's the + + align:start position:0% +okay and were we're back so what's the + + + align:start position:0% +okay and were we're back so what's the +first step in a problem like this the + + align:start position:0% +first step in a problem like this the + + + align:start position:0% +first step in a problem like this the +first step is figuring out what our + + align:start position:0% +first step is figuring out what our + + + align:start position:0% +first step is figuring out what our +equation looks like the one that we're + + align:start position:0% +equation looks like the one that we're + + + align:start position:0% +equation looks like the one that we're +going to affine so our equation is going + + align:start position:0% +going to affine so our equation is going + + + align:start position:0% +going to affine so our equation is going +to look like C T plus DT squared equals + + align:start position:0% +to look like C T plus DT squared equals + + + align:start position:0% +to look like C T plus DT squared equals +y so that's what we're looking for we're + + align:start position:0% +y so that's what we're looking for we're + + + align:start position:0% +y so that's what we're looking for we're +looking for a quadratic equation through + + align:start position:0% +looking for a quadratic equation through + + + align:start position:0% +looking for a quadratic equation through +the origin now if it were just any + + align:start position:0% +the origin now if it were just any + + + align:start position:0% +the origin now if it were just any +quadratic equation then we would have a + + align:start position:0% +quadratic equation then we would have a + + + align:start position:0% +quadratic equation then we would have a +constant term but through the origin + + align:start position:0% +constant term but through the origin + + + align:start position:0% +constant term but through the origin +just means that the constant term is + + align:start position:0% +just means that the constant term is + + + align:start position:0% +just means that the constant term is +zero okay now what's the next step next + + align:start position:0% +zero okay now what's the next step next + + + align:start position:0% +zero okay now what's the next step next +we need to set up a matrix equation so + + align:start position:0% +we need to set up a matrix equation so + + + align:start position:0% +we need to set up a matrix equation so +we need an a a matrix a oops and which + + align:start position:0% +we need an a a matrix a oops and which + + + align:start position:0% +we need an a a matrix a oops and which +which matrix is that going to a B well + + align:start position:0% +which matrix is that going to a B well + + + align:start position:0% +which matrix is that going to a B well +let me start with the first coordinate + + align:start position:0% +let me start with the first coordinate + + + align:start position:0% +let me start with the first coordinate +of these three points and I'm going to + + align:start position:0% +of these three points and I'm going to + + + align:start position:0% +of these three points and I'm going to +put them in the first column of this + + align:start position:0% +put them in the first column of this + + + align:start position:0% +put them in the first column of this +matrix 1 2 negative 1 and then my second + + align:start position:0% +matrix 1 2 negative 1 and then my second + + + align:start position:0% +matrix 1 2 negative 1 and then my second +column is going to be the squares of + + align:start position:0% +column is going to be the squares of + + + align:start position:0% +column is going to be the squares of +these first coordinates 1 4 and 1 and my + + align:start position:0% +these first coordinates 1 4 and 1 and my + + + align:start position:0% +these first coordinates 1 4 and 1 and my +x hat + + align:start position:0% +x hat + + + align:start position:0% +x hat +that's just C and D and my B this is + + align:start position:0% +that's just C and D and my B this is + + + align:start position:0% +that's just C and D and my B this is +going to be the second coordinates 1 5 + + align:start position:0% +going to be the second coordinates 1 5 + + + align:start position:0% +going to be the second coordinates 1 5 +and negative 2 + + align:start position:0% + + + + align:start position:0% + +okay why did I set this problem up like + + align:start position:0% +okay why did I set this problem up like + + + align:start position:0% +okay why did I set this problem up like +that well multiply a times X hat okay + + align:start position:0% +that well multiply a times X hat okay + + + align:start position:0% +that well multiply a times X hat okay +the first coordinate of a times X hat is + + align:start position:0% +the first coordinate of a times X hat is + + + align:start position:0% +the first coordinate of a times X hat is +1 times C plus 1 times D it's just the + + align:start position:0% +1 times C plus 1 times D it's just the + + + align:start position:0% +1 times C plus 1 times D it's just the +same as plugging in this first point + + align:start position:0% +same as plugging in this first point + + + align:start position:0% +same as plugging in this first point +into the left-hand side of this equation + + align:start position:0% +into the left-hand side of this equation + + + align:start position:0% +into the left-hand side of this equation +okay and similarly if I took the second + + align:start position:0% +okay and similarly if I took the second + + + align:start position:0% +okay and similarly if I took the second +point and plugged it in here I would + + align:start position:0% +point and plugged it in here I would + + + align:start position:0% +point and plugged it in here I would +just get 2 times C plus 4 times D which + + align:start position:0% +just get 2 times C plus 4 times D which + + + align:start position:0% +just get 2 times C plus 4 times D which +is just the same as the second + + align:start position:0% +is just the same as the second + + + align:start position:0% +is just the same as the second +coordinate in + + align:start position:0% +coordinate in + + + align:start position:0% +coordinate in +multiplication a times X had 2 times C + + align:start position:0% +multiplication a times X had 2 times C + + + align:start position:0% +multiplication a times X had 2 times C +plus 4 times D ok and where did the B + + align:start position:0% +plus 4 times D ok and where did the B + + + align:start position:0% +plus 4 times D ok and where did the B +come from well via B came from plugging + + align:start position:0% +come from well via B came from plugging + + + align:start position:0% +come from well via B came from plugging +in these points to the right hand side + + align:start position:0% +in these points to the right hand side + + + align:start position:0% +in these points to the right hand side +so 1 5 and negative 2 are just the Y + + align:start position:0% +so 1 5 and negative 2 are just the Y + + + align:start position:0% +so 1 5 and negative 2 are just the Y +coordinates of these three points good + + align:start position:0% +coordinates of these three points good + + + align:start position:0% +coordinates of these three points good +so what it would be great if if we get + + align:start position:0% +so what it would be great if if we get + + + align:start position:0% +so what it would be great if if we get +solved ax hat equals B but we can't + + align:start position:0% +solved ax hat equals B but we can't + + + align:start position:0% +solved ax hat equals B but we can't +solve ax hat equals B because there + + align:start position:0% +solve ax hat equals B because there + + + align:start position:0% +solve ax hat equals B because there +isn't a quadratic equation through the + + align:start position:0% +isn't a quadratic equation through the + + + align:start position:0% +isn't a quadratic equation through the +origin that contains these 3 points but + + align:start position:0% +origin that contains these 3 points but + + + align:start position:0% +origin that contains these 3 points but +we need to find the best approximation + + align:start position:0% +we need to find the best approximation + + + align:start position:0% +we need to find the best approximation +to that so that's the same as solving ax + + align:start position:0% +to that so that's the same as solving ax + + + align:start position:0% +to that so that's the same as solving ax +hat equals the projection of B onto the + + align:start position:0% +hat equals the projection of B onto the + + + align:start position:0% +hat equals the projection of B onto the +column space of a because we only have a + + align:start position:0% +column space of a because we only have a + + + align:start position:0% +column space of a because we only have a +chance of solving ax hat equals + + align:start position:0% +chance of solving ax hat equals + + + align:start position:0% +chance of solving ax hat equals +something if it's in the column space of + + align:start position:0% +something if it's in the column space of + + + align:start position:0% +something if it's in the column space of +a and remember from our projections part + + align:start position:0% +a and remember from our projections part + + + align:start position:0% +a and remember from our projections part +of the class that this is the same as + + align:start position:0% + + + + align:start position:0% + +solving a transpose a X hat equals a + + align:start position:0% +solving a transpose a X hat equals a + + + align:start position:0% +solving a transpose a X hat equals a +transpose B good so that's what we're + + align:start position:0% +transpose B good so that's what we're + + + align:start position:0% +transpose B good so that's what we're +really going to adieu we're really going + + align:start position:0% +really going to adieu we're really going + + + align:start position:0% +really going to adieu we're really going +to solve a transpose ax hat equals a + + align:start position:0% +to solve a transpose ax hat equals a + + + align:start position:0% +to solve a transpose ax hat equals a +transpose B and now all we have to do is + + align:start position:0% +transpose B and now all we have to do is + + + align:start position:0% +transpose B and now all we have to do is +just a computation so let's do it so + + align:start position:0% +just a computation so let's do it so + + + align:start position:0% +just a computation so let's do it so +what is a transpose a going to do this + + align:start position:0% +what is a transpose a going to do this + + + align:start position:0% +what is a transpose a going to do this +kind of quickly because you should be + + align:start position:0% +kind of quickly because you should be + + + align:start position:0% +kind of quickly because you should be +good at multiplying matrices by now + + align:start position:0% + + + + align:start position:0% + +yeah sorry oh this I have the negative + + align:start position:0% +yeah sorry oh this I have the negative + + + align:start position:0% +yeah sorry oh this I have the negative +in the wrong place thank you thanks for + + align:start position:0% +in the wrong place thank you thanks for + + + align:start position:0% +in the wrong place thank you thanks for +that correction I have the negative + + align:start position:0% +that correction I have the negative + + + align:start position:0% +that correction I have the negative +backwards they're good okay and what do + + align:start position:0% +backwards they're good okay and what do + + + align:start position:0% +backwards they're good okay and what do +I get when I multiply these I'll let you + + align:start position:0% +I get when I multiply these I'll let you + + + align:start position:0% +I get when I multiply these I'll let you +check this is six eight eight and a ten + + align:start position:0% +check this is six eight eight and a ten + + + align:start position:0% +check this is six eight eight and a ten +okay and what is a transpose B well if + + align:start position:0% +okay and what is a transpose B well if + + + align:start position:0% +okay and what is a transpose B well if +you multiply this out all let you check + + align:start position:0% +you multiply this out all let you check + + + align:start position:0% +you multiply this out all let you check +that you get 13 and a 19 good so this is + + align:start position:0% +that you get 13 and a 19 good so this is + + + align:start position:0% +that you get 13 and a 19 good so this is +this is just some computation and so + + align:start position:0% +this is just some computation and so + + + align:start position:0% +this is just some computation and so +what we're solving here is 6 8 8 10 + + align:start position:0% +what we're solving here is 6 8 8 10 + + + align:start position:0% +what we're solving here is 6 8 8 10 +times X hat equals 13 19 and we remember + + align:start position:0% +times X hat equals 13 19 and we remember + + + align:start position:0% +times X hat equals 13 19 and we remember +how to do this just by using elimination + + align:start position:0% +how to do this just by using elimination + + + align:start position:0% +how to do this just by using elimination +we replace the second row by 3 times the + + align:start position:0% +we replace the second row by 3 times the + + + align:start position:0% +we replace the second row by 3 times the +second row minus 4 times the first row + + align:start position:0% +second row minus 4 times the first row + + + align:start position:0% +second row minus 4 times the first row +again I'm going to do this quickly + + align:start position:0% +again I'm going to do this quickly + + + align:start position:0% +again I'm going to do this quickly +because you know this from other parts + + align:start position:0% +because you know this from other parts + + + align:start position:0% +because you know this from other parts +of the class you similarly change the B + + align:start position:0% +of the class you similarly change the B + + + align:start position:0% +of the class you similarly change the B +vector and we back solve to get D is + + align:start position:0% +vector and we back solve to get D is + + + align:start position:0% +vector and we back solve to get D is +negative five-halves and C equals let's + + align:start position:0% +negative five-halves and C equals let's + + + align:start position:0% +negative five-halves and C equals let's +plug that and then C I think you're + + align:start position:0% +plug that and then C I think you're + + + align:start position:0% +plug that and then C I think you're +going to get 11 over 2 so what's our + + align:start position:0% +going to get 11 over 2 so what's our + + + align:start position:0% +going to get 11 over 2 so what's our +final equation our final equation is y + + align:start position:0% +final equation our final equation is y + + + align:start position:0% +final equation our final equation is y +equals 11 halves t minus 5 halves T + + align:start position:0% +equals 11 halves t minus 5 halves T + + + align:start position:0% +equals 11 halves t minus 5 halves T +squared + + align:start position:0% + + + + align:start position:0% + +good okay so this is our best fit + + align:start position:0% +good okay so this is our best fit + + + align:start position:0% +good okay so this is our best fit +quadratic equation through the origin + + align:start position:0% +quadratic equation through the origin + + + align:start position:0% +quadratic equation through the origin +now before I end let me do a couple + + align:start position:0% +now before I end let me do a couple + + + align:start position:0% +now before I end let me do a couple +things first let me go back and review + + align:start position:0% +things first let me go back and review + + + align:start position:0% +things first let me go back and review +what the key steps were whenever you're + + align:start position:0% +what the key steps were whenever you're + + + align:start position:0% +what the key steps were whenever you're +faced with such a best-fit equation + + align:start position:0% +faced with such a best-fit equation + + + align:start position:0% +faced with such a best-fit equation +first you want to see what the general + + align:start position:0% +first you want to see what the general + + + align:start position:0% +first you want to see what the general +form of the equation is next you want to + + align:start position:0% +form of the equation is next you want to + + + align:start position:0% +form of the equation is next you want to +write it in terms of matrices write down + + align:start position:0% +write it in terms of matrices write down + + + align:start position:0% +write it in terms of matrices write down +your your matrix a and your vector B and + + align:start position:0% +your your matrix a and your vector B and + + + align:start position:0% +your your matrix a and your vector B and +lastly you set up your projection + + align:start position:0% +lastly you set up your projection + + + align:start position:0% +lastly you set up your projection +equation and then all you have to do is + + align:start position:0% +equation and then all you have to do is + + + align:start position:0% +equation and then all you have to do is +just a computation good it might also be + + align:start position:0% +just a computation good it might also be + + + align:start position:0% +just a computation good it might also be +worth noting that um these three points + + align:start position:0% +worth noting that um these three points + + + align:start position:0% +worth noting that um these three points +certainly aren't on this quadratic + + align:start position:0% +certainly aren't on this quadratic + + + align:start position:0% +certainly aren't on this quadratic +equation for instance if I plug in one + + align:start position:0% +equation for instance if I plug in one + + + align:start position:0% +equation for instance if I plug in one +here I don't get one one I get one three + + align:start position:0% +here I don't get one one I get one three + + + align:start position:0% +here I don't get one one I get one three +but that's that's okay this is as close + + align:start position:0% +but that's that's okay this is as close + + + align:start position:0% +but that's that's okay this is as close +as we can do thanks \ No newline at end of file diff --git a/ejZtBwLUE3Y.txt b/ejZtBwLUE3Y.txt new file mode 100644 index 0000000000000000000000000000000000000000..71dc962d1d75d8e0ab321941b4ea108e24480766 --- /dev/null +++ b/ejZtBwLUE3Y.txt @@ -0,0 +1,2840 @@ +The following content is +provided under a Creative + +Commons license. + +Your support will help MIT +OpenCourseWare continue to + +offer high quality educational +resources for free. + +To make a donation, or view +additional materials from + +hundreds of MIT courses, visit +MIT OpenCourseWare at + +ocw.mit.edu. + +PROFESSOR: Ladies and gentlemen, +welcome to + +lecture number 12. + +In this lecture, I would like +to discuss with you solution + +methods for eigenproblems. + +This is a very large field, +and all I can do really in + +this lecture is to give you or +discuss this you a few of the + +solution methods that +we are using in + +finite element analysis. + +So it will be a very brief +introduction, a brief survey + +of the methods of solution that +we're using for finite + +element eigenvalue problems. + +The generalized eigenvalue +problem, K phi equals lambda M + +phi, is a problem that we +encountered in the multiple + +position analysis. + +Please recognize that I'm +calling lambda here, the + +eigenvalue, which was our omega + +squared in the last lecture. + +This is really the eigenproblems +that we are + +primarily addressing ourselves +to finite element analysis. + +The standard eigenproblems +problem here, EVP stands for + +eigenproblem, has M equal +to the identity matrix. + +So when we're talking about +solution methods of this + +problem, we're really also talk +about solution methods of + +this problem. + +If we have, in a [? multiple ?] +position + +analysis, non-proportional +damping, then we would have to + +solve this eigenproblem, which +is a quadratic eigenproblem. + +I will not address myself to the +solution of this problem, + +so in what follow, we are +talking about a solution of + +this problem, and of course, the +solution of this problem + +also, when M is equal to +the identity matrix. + +In particular, we are interested +in the solution of + +large eigenvalue problems when +N, is say, greater than 500. + +N, of course, being the order of +K and M, and with the half + +bandwidth, I should say, +being greater than 60. + +The number of eigenvalues that +we will be looking for, that + +we want to calculate, are say, +1 to 1/3 of N. 1/3 of N is + +already large number +of eigenvalues. + +Generally, we are talking about +1 to and at most, 100 + +for large eigenproblems. + +When we have a small eigenvalue +problem, in other + +words, N being small, say 50 +or 100, there are a large + +number of different techniques +that can be used to solve this + +eigenvalue problem, and it +really does not make that much + +difference which technique +you are using. + +The cost can still be quite +significant, but certainly, + +when we're talking about very +large eigenproblems, N being + +even larger than a 1,000 or +2,000, then it is of up most + +concern to select a technique +that is very effective. + +And I want to address myself +really now towards those + +techniques that we feel are +very effectively used in + +finite element analysis. + +In dynamic analysis, of course, +with proportional + +damping, this was the eigenvalue +problem that we + +wanted to solve. + +Now, if they are 0 frequencies +present, in other words, when + +we have rigid body modes in the +system, then we can use + +the following procedure to +basically getting rid of these + +0 frequencies. + +We simply add, on the left hand +side, a mu M phi, and on + +the right hand side, +a mu M phi. + +And taking these two together, +we are getting this + +coefficient matrix, and +a new lambda value. + +That lambda value now is omega +squared plus mu, where omega + +squared is equal to +lambda minus mu. + +What we have been doing here, +is basically, we have been + +applying a shift. + +In other words, if we were to +plot the characteristic + +polynomial, giving us +the eigenvalues, the + +characteristic polynomial of +course, being p of lambda + +being determined K bar minus +lambda M, where K bar is equal + +to K plus mu M. + +If we plug this characteristic +polynomial, we will see this + +curve here, schematically drawn, +of course, where the + +omega squared values would start +here, in other words, + +the lowest omega squared +value is, in fact, 0. + +Whereas our lambda value +now starts right here. + +This is the shift that +we [? imposed. ?] + +So, basically, we now recognize +that we have all + +eigenvalues being greater than +0, because this is our new + +starting value. + +All eigenvalues measured from +here are greater than 0, the + +smallest one being mu, +namely when omega + +squared is equal to 0. + +And the larger ones +being here. + +It is effective to perform such +a shift when we have 0 + +eigenvalues, in other words, to +operate on this eigenvalue, + +rather than on that one, because +our techniques then + +are very stable and effective, +and this shift here is, in + +general, therefore performed. + +So all we have to address +ourselves to then from now on, + +is really, the solution of +eigenvalues and eigenvectors, + +when all of the eigenvalues +are greater than 0. + +If we start off with a problem +where we have a 0 frequency, + +we apply the shift so that the +eigenvalues now of this + +problem here are all +greater than 0. + +In buckling analysis, we +have this eigenproblem. + +We really did not talk about-- + +we did not really at all about +buckling analysis in the set + +of lectures, but you might just +be interested in finding + +out how would we solve for +these eigenvalues. + +Well, here is the characteristic +polynomial. + +The smallest lambda value, of +course, gives now a critical + +load, that is the one e would +be interested in. + +It is effective here, +to rewrite this + +problem in this form. + +All we do, is we are taking +the lambda value onto the + +other side. + +In other words, we +are dividing this + +equation here by a lambda. + +So that one of the lambda stands +on this side, and KG + +phi on that side. + +The resulting problem is this +one, where kappa is 1 over + +lambda and we have now +here, is a K matrix. + +K is positive definite, and now +it is more effective to + +operate on this equation. + +How do we obtain now +the largest kappa? + +Because the largest kappa is the +one that we are interested + +in, which corresponds to the +smallest lambda, the smallest + +buckling load. + +Well, we would now perform +a shift to the right, + +subtracting mu K from this side, +from this side, and from + +that side, to obtain this +eigenvalue problem. + +That means we are really +shifting from here up to + +there, and now we are interested +in solving kappa N + +by operating on this +eigenproblems problem. + +It is this eigenvalue problem +that we can operate on + +directly, using the techniques +that I would be discussing + +later, to determine search +method and the subspace + +iteration method. + +But before we get into those +techniques, I would like to + +discuss with you some +preliminary considerations + +that are important +when we look at + +an eigenvalue solution. + +The important first point that +I want to make is that there + +is a traditional approach +for the solution of this + +eigenvalue problem here. + +Let's look at this eigenvalue +problem. + +Where of course, when we're +talking about a buckling + +analysis, we would have +different matrices here, but + +basically, we still solve +this eigenvalue problem. + +The traditional approach lies +in factorizing the M matrix + +into Cholesky factors. + +We talked about the Cholesky +factor when we talked about + +solution of equations. + +So here it comes up again. + +We would factorize the M matrix +into Cholesky factors, + +as shown here. + +We define now a new eigenvector, +phi curl being + +equal as shown here, L curl +transpose times 5. + +We substitute from here into +there, and we directly obtain + +this eigenvalue problem here. + +Now we have the standard +eigenproblem. + +Now once we have a standard +eigenproblem, there are a + +large number of techniques +that can be used. + +For example, the QR method, +the standard + +Jacobi method, et cetera. + +So this is, what +we might call. + +a traditional approach to +solve the generalized + +eigenproblem, this is the one +here that we are really + +interested in. + +But it involves this +transformation, and this + +transformation here can involve +a very significant + +cost, because we have to find +these Cholesky factors and + +then, of course, we have to +calculate this K curl. + +Another way of performing +a transformation of the + +generalized item problem to a +standard form would be to + +solve the eigenproblem +of M first. + +W here and W transpose +[? store ?] + +the eigenvectors of the M +matrix, and D squared is a + +diagonal matrix of the +eigenvalues of M. And then + +having factored M in this form, +an equation similar to + +this one here can be written. + +Where now, the transformation, +of course, involves the + +eigenvectors, W. + +Well, this approach is +sometimes still quite + +effective, but in general, it +cannot be recommended because + +there's too much cost involved +in the factorizing of the M + +matrix, and then particular, +in the transformation here, + +and the solution of this problem +and the, of course, to + +get from this problem, the phi +vector, we have to go back to + +this equation. + +A direct solution of the +generalized eigenvalue problem + +that we want to solve is +really more effective. + +And now, we are ordering the +lambdas as shown here. + +Remember, our smallest lambda +now is greater than 0, the + +eigonvectors are stored as shown +here, and for most of a + +position analysis, we are really +interested in solving + +only for a certain number of +eigen pairs, i equals 1 to p, + +as discussed in the last +lecture, or i equals r to s. + +If we have a vibration +excitation problem, we really + +only want to solve for specific +frequencies and + +corresponding mode shapes +in a certain + +interval, as shown here. + +The solution procedures on this +generalized eigenvalue + +problem can be categorized +into the following forms. + +The first solution procedure, +or a whole class of solution + +procedures, that I should really +say, which we might + +call the vector iteration +techniques. + +The idea is the following-- + +if we want to solve this +problem, then why not solve it + +in the following way? + +Start off with a vector on this +side, that we assume, + +calculate a new vector on this +side, then take that new + +vector, plug it back on the +right hand side, and cycle + +through this way. + +This is indeed inverse +iteration. + +What do we do here? + +We are putting a vector on the +right hand side, x1, when K is + +equal to 1, that vector +we have to assume. + +Then we are multiplying out +the right hand side. + +Now we have a set of +simultaneous equations that we + +would solve just in the same way +as we solve the equations + +in static analysis. + +We can think of this +as a load vector. + +We are calculating this +displacement vector, and then + +having got this displacement +vector, and not taking care of + +this lambda, or having, +basically, taken this lambda + +out of this equation. + +Which means that this vector +will grow in lengths, or + +collapse in lengths. + +Therefore, want to scale this +vector down to a good length-- + +a length that does not hit +overflow, so to say, or + +underflow in the machine. + +And that scaling is achieved +as shown here. + +So, the final result then, this +is just a scalar here, as + +you can see, is a vector here, +which we can put on to the + +right hand side and keep +on iterating around. + +In fact, we find as that +iteration procedure converges + +to the lowest eigenvector, +provided the starting vector + +is not orthogonal, is not +M orthogonal to phi 1. + +This is one first iteration +technique. + +Maybe I should put +a side note down. + +A side note that many of you +might have in your mind. + +Many of you might have the +following question in your + +mind-- why he iterate, why does +he not solve directly for + +the eigenvalues? + +Just like we saw a set of +simultaneous equations. + +Well, there's one very important +point, and this is + +the point-- + +if we are solving an eigenvalue +problem, and shown + +here, then really that +means the following-- + +we are saying that determinant, +K minus lambda M + +shall be equal to 0. + +Why? + +Because if we write +this equation in + +the following form-- + +K minus lambda M times phi +equals 0, then we have here a + +set of simultaneous equations +with a 0 vector on + +the right hand side. + +And there is an important +theorem in linear algebra that + +says, only a solution to this +set of equations when this + +coefficient matrix +is singular. + +Which means that the +determinant of this + +coefficient matrix must be 0. + +So, what do we want? + +We really want to solve p of +lambda determinant, K minus + +lambda M. We want to solve for +the 0's of this polynomial. + +That's really what we want. + +Now, if we want to solve for +the 0's of this polynomial, + +then we also have to understand +that when k is of + +order 4, there will +be four 0's. + +The polynomial itself +will be of order 4. + +If K is of order, N, then +there will be N 0's. + +So the polynomial is order N. +However, if we want to find + +the solution of a polynomial, +or order N, then we very + +quickly find that, in fact, we +can only look up the solution + +to such polynomials if they are +of low enough order, lower + +than say, 4. + +Above for larger order +polynomials, there's no way + +you can look up the solution. + +You have to iterate to obtain +the solution of the 0's of + +this polynomial. + +However, since this problem +here, is completely equivalent + +to this problem. + +To solve this problem, +you have to iterate. + +And this is the important +conclusion. + +It is of up most importance that +you understand that to + +solve an eigenvalue problem of +order larger than say, 4, you + +will have to iterate. + +Because you're solving for the +0's of a polynomial of order + +larger than 4. + +Only for very small order +polynomials, we can look up + +the solutions in handbooks. + +So having grasped the fact that +we have to iterate to + +solve for the 0's of this +polynomial, to solve for the + +eigenvalues of this problem, we +are stuck with iteration, + +and since we're stuck with +iteration, we now want to come + +up with techniques to iterate. + +And the first technique to +iterate is this vector + +iteration technique. + +And the basic idea, once more, +is if you want to solve this + +equation, well, then why not +iterate in the following way? + +Put some starting value in here, +this number is just a + +scalar, let's neglect that +effect for the moment. + +And having put a starting value +in here, calculate this + +one and keep on cycling +around this way. + +And that's what we call +inverse iteration. + +Inverse iteration here, a vector +inverse iteration, + +because we have to solve a set +of equations here, with K as + +the coefficient matrix. + +There are other iteration +techniques. + +There's also forward +iteration. + +And basically, what we're +saying there is-- + +well if we are starting off here +and going around in this + +circle, why not start off here +and go around in that circle, + +the red line. + +And that, in fact, gives +us forward iteration. + +One can prove that that forward +iteration converges to + +the largest eigenvalue. + +We are usually interested in the +smallest frequencies, the + +smallest eigenvalues, and +therefore, we are using + +inverse iteration +quite commonly. + +Then there is Rayleigh +Quotient iteration. + +The Rayleigh Quotient iteration +is again, an inverse + +iteration, however, with an +acceleration scheme in it, a + +very effective acceleration +scheme. + +This Rayleigh Quotient iteration +can be employed to + +calculate one eigenvalue and +vector, and then, of course, + +we have to deflate afterwards +the matrix, the coefficient + +matrix for the eigenvector +that we have calculated + +already, and we then could go on +towards the calculation of + +additional eigenvalues +and vectors. + +The same deflation also would +be used in inverse iteration + +alone, and in forward +iteration alone. + +In a Rayleigh Quotient +iteration, we converge to an + +eigen pair, but which one +is not guaranteed. + +So this is a class of +techniques, iteration methods + +that we are using. + +Another class of techniques, +again iteration methods, we + +are stuck with iteration, as +I mentioned earlier, is the + +polynomial iteration methods. + +Here, we are saying that this +problem is equivalent to that, + +we want to solve +for these 0's. + +Therefore, for the 0's of this +polynomial, sketched out here, + +and one way is to use +Newton iteration. + +Here we have p, here +we have p prime. + +Well, of course, if we have +p here, we have to also + +recognize we should have +the coefficients here. + +Well, these coefficients are +given here, A0 to a n. + +And we could rewrite this +polynomial in this form, once + +we know the zeroes. + +Now, if we don't know the +zeroes, of course, we would be + +stuck on iterating on this +matrix, where we would have to + +calculate these coefficients. + +However, there are now really, +two different techniques. + +The first technique is explicit +polynomial iteration. + +In the explicit polynomial +iteration, we expand the + +polynomial and iterate for the +0's, by that I mean, we + +actually expand this +polynomial. + +However, this technique is not +suitable for larger problems + +because first of all, there's +much work to obtain the ai's, + +and then it's an unstable +process. + +Unstable because small errors +in these coefficients here, + +give large errors +in the zeroes. + +So this is not a suitable +technique, and we are better + +off using implicit polynomial +iteration. + +In the implicit polynomial +iteration, we evaluate the + +determinant all this +matrix here. + +In others, p at mu i, via the L +D L transpose factorization, + +which we discussed in the Gauss +elimination solution, + +when we talked about Gauss +elimination solution. + +To obtain the determinant of +this matrix here then, we need + +simply to multiply all the +diagonal elements. + +This technique is accurate, +provided we do not encounter + +large multipliers L matrix. + +And if we do, we have to +shift away, we have to + +change our mu i. + +Also we directly solve for +lambda 1 and so on. + +And for the more we can use +effectively a secant + +iteration, instead of +calculating, in other words, + +the p prime at mu. + +This is here approximately equal +to p prime, at mu i. + +Instead of calculating this +derivative, we are putting + +this value here, which gives +us an approximation to that + +derivative, this is what we +call the secant iteration. + +Once we have calculated one +eigenvalue, of course, we will + +have to deflate to calculate the +next eigenvalue, and this + +is the process that +he would pursue. + +Pictorially, we have here, +our p lambda, this is the + +polynomial. + +Let me show it to you here. + +Here, we have the polynomial, +here we have lambda 1, here we + +have lambda 2. + +In the secant iteration, we +start off with the value of mu + +i minus 1 here, mu i, these +two values are given. + +Usually, in a practical +analysis, mu 0 would be this + +value here, and mu 1 would be +a lower bound on lambda 1. + +And plugging these two values +in, we get mu i plus 1, and + +you can see that this process +would then converge to this + +eigenvalue. + +Once we have lambda 1, we can +repeat the iteration. + +However, working now on p +lambda divided by lambda + +minus lambda 1. + +And that means we are operating +on this polynomial + +here, and polynomial then gives +us the iteration on that + +polynomial then gives us +the second eigenvalue. + +So we are deflating the actual p +lambda by the lambda 1 value + +in order to obtain +a convergence + +to the second value. + +Well, this is the one +class of methods. + +Another class of methods, the +third one, are the Sturm + +sequence methods. + +And here, the basic idea +is the following-- + +if we look at this eigenproblem, +and I use a 4x4 + +matrix here, then if we take a +shift on this eigenproblem, mu + +S, and this is the shift here. + +Then if we factorize K minus +mu S M, equal to L D L + +transpose, again, we're using +our Gauss elimination + +procedures basically. + +Then the number of negative +elements in D is equal to the + +number eigenvalues smaller +than mu S, a + +very important point. + +Let us look at this example +here of the 4x4 matrix. + +Here we have plotted +characteristic polynomials. + +The characteristic polynomial of +this 4x4 matrix, with that + +M matrix, of course, is drawn +along here, four eigenvalues. + +And I have put mu S here +as the red line. + +What this theorem says is if I +factorize K minus mu S, M, + +this being the K matrix, the +total K matrix, and the 4x4 M + +matrix goes in here. + +Then there would be one negative +element in D. One + +only because mu S is large +than lambda 1. + +If mu S were on this side +here, there would be two + +negative elements in D. If mu +S were on this side, there + +would be three negative +elements in D-- + +very important point because qw +can use this procedure to + +directly calculate eigenvalues +the way I will be discussing + +it just now. + +However, let us look a little +bit more at why + +this hole is here. + +Well, it derives from the +associated constraint problems + +with the original +eigenproblem. + +The original eigenproblem +corresponds to this beam + +problem, which we considered +earlier already in the + +discussion of Gauss +elimination. + +If I constrain this degree of +freedom here, I get a new + +polynomial corresponding to +this problem, and the + +important point is that the +lowest root, the lowest value + +of this problem here lies in +between these two-- lambda 1 + +and lambda 2. + +The second one here, lies +between lambda 2 and lambda 3, + +and the third one here lies +between lambda 3 and lambda 4. + +The second associated constraint +problem has two + +eigenvalues, and this one lies +between these two, this one + +lies between these two. + +And the final eigenvalue +problem here, the third + +associate constraint problem +obtained by knocking out these + +degrees of freedom here, has one +eigenvalue, and that one + +lies in between these +two values here. + +It's this important fact +that is used to + +derive this final result. + +Now, we have not time to go +through the actual details, + +but this is the important +fact here. + +In other words, that the +[? i's ?] eigenvalue of this + +associated constraint problem, +for example, the second + +eigenvalue of this associated +constraint problem here, + +bisects or lies in between, +not bisect-- + +lies in between lambda 2 and +lambda 3 of this eigenproblem + +here, and so on. + +That result is used to derive +this final result, which we + +use effectively then in +the eigen solution. + +And the class of techniques then +that we are referring to + +using this fact are the Sturm +sequence methods. + +So basically, what we are saying +is the following-- + +take this coefficient matrix, +now I make the mu x available. + +We factorize that coefficient +matrix into L D L transposed, + +and the number of negative +elements in D is equal to the + +number of eigenvalues smaller +than mu S, I. How + +do we use this fact? + +Well, if this is here, the +polynomial, we could start off + +by putting mu S 1 into this +point here, and we would find + +out the number of eigenvalues +smaller than mu S 1. + +Then we are taking, mu S 2, and +we find out the number of + +eigenvalues smaller +than mu S 2. + +Of course, we would find that +they are one more eigenvalue + +smaller than mu S 2. + +Then mu S 1, namely this one. + +So we know there's one +eigenvalue in between mu S 1 + +and mu S 2. + +Now we could bisect this +interval, and we would find + +that, in fact, there is still +one more eigenvalue smaller + +than mu S 3, then there was +smaller than mu S 1. + +Because this eigenvalue +still lies on the left + +side of mu S 3. + +So we bisect again, +we get mu S 4. + +Notice this distance here, is +equal to that distance here. + +And now, we would find that the +eigenvalue still lies in + +between these two lines, between +mu S 3 and mu S 4. + +And like that. we could +continue bisecting the + +interval until we finally find a +very small interval in which + +this eigenvalue must lie. + +We, of course, have to take care +in the L D L transpose + +factorization, because we are +not working on a positive + +definite matrix. + +The multipliers must be small, +the L, I, J elements must + +remain small in the +factorization. + +But provided that is the case, +the round of errors are small, + +and the procedure +is very stable. + +However, convergence can be very +slow, can be extremely + +slow because you have to cut +down the intervals further and + +further until you finally get +a very small interval, in + +which you now know the +eigenvalue does lie. + +Of course, at some point, you +might want to switch to + +another iteration scheme. + +Once you know there is an +eigenvalue in between say mu S + +3 and mu S 4, you might want +to switch to a iteration + +scheme that converges to this +particular value much faster. + +Finally, a whole class of +methods that I would like to + +briefly mention to you are the +methods of transformations, + +where we are operating on +this eigenvalue problem, + +recognizing that phi transpose +K phi is equal to lambda. + +And phi transpose M phi is +equal to I. Where phi is + +defined as shown here, lambda +is defined as shown here. + +This fact, of course, we use +already earlier in the + +[? multiple ?] + +position analysis. + +Now how can we get +phi and lambda? + +That is our objective. + +Well, if we know that this +matrix diagonalizes the K + +matrix, and it also diagonalizes +the M matrix, + +then why not try to construct +it by iteration? + +And this is the basic idea in +the transformation methods. + +What we do is the following-- we +take the original K matrix, + +we are operating with +P1 transpose K P1. + +On K, and on M, such as to make +this resultant matrix + +here closer to a +diagonal form. + +Ultimately, we want to get +a diagonal matrix. + +Well, one step in the iteration +is to make this P1 + +transpose K P1 matrix, and P1 +transpose M P1 matrix, both of + +these matrices a little closer +to diagonal form. + +Then K and M were +by themselves. + +So this is the first step. + +Now, we have here, let's call +this a K2 matrix, and this + +here an M2 matrix. + +Now, we are operating with P2 +transpose on K2, and also + +there's a P2 here. + +So let me take a different color +to show that now we are + +operating with this part here, +and that part there. + +And this, of course, we are +doing in such a way as to have + +that P2 transposed, K2, P2 +is a little bit closer to + +diagonal form than was K2. + +I hope you can see these +lines-- let me put + +them in once more. + +What I'm saying is we have K2 +after having applied P1 + +transpose on P1, on K, +and similar for M. + +And now we want to make K2 still +a little bit closer to + +diagonal form. + +Well, we are now applying P2 +transposed on K2 and the P2 on + +K2, this one here has been +replaced by K2, this one here + +has been replaced by M2. + +And what we're saying is that +this final result, in this + +final result should be closer +to diagonal form. + +In fact, this should be closer +to I matrix, and this should + +be closer to the lambda +matrix, ideally. + +Well, this is the basic process +that is used in the + +generalized Jacobi method. + +We can show that if +we choose specific + +matrices, P I matrices. + +That zero always one [? of ?] +diagonal element. + +In other words, the P I matrix, +zeroes a particular + +off diagonal element in this +current coefficient matrix, + +similarly for the M2, for the +current M coefficient matrix. + +Then we know in the generalized +Jacobi method that + +the process finally converges. + +It converges and we get a +diagonal matrix here. + +With proper scaling, it will +be the identity matrix. + +And here, we are getting also a +diagonal matrix, and if this + +is an identity matrix, this will +actually be the matrix + +storing the eigenvalues. + +Well, this is the generalized +Jacobi method here. + +They are other techniques that +can also be used, of course, + +this is a very common approach +taken when we have M being + +equal to the identity matrix. + +However, the disadvantage of +this approach is that we are + +calculating all eigen pairs +simultaneously. + +In finite element analysis, +we are only interested in + +specific eigenvalues, so lowest +P, or a certain number + +of eigenvalues in an interval. + +Here, we have to calculate all +of the eigenvalues stored in + +the lambda matrix, and all +of the eigenvectors. + +And the eigenvectors here, would +be these vectors here. + +These are the the matrix phi, +which is P1 times P2, up to P + +K, after K steps of iteration. + +This gives us the matrix +phi, storing all of the + +eigenvectors. + +So the disadvantage is that we +are calculating all of that + +eigenvectors, which in finite +element analysis is hardly + +ever required. + +All we want is the total number +of eigenvalues and + +eigenvectors. + +Remember, also if K +is of [? order ?] + +1,000, this would be a +tremendous amount of work + +involved and, in fact, it would +be beyond the current + +state of computing capabilities +to use a + +generalized Jacobi method on a +K matrix 1,000x1,000 and an M + +matrix 1,000x1,000. + +You will certainly stretch the +current computing capabilities + +tremendously by using the +generalized Jacobi method on + +large eigenproblems. + +For large eigenproblems, it is +really best to combine the + +basic approaches that +I just mentioned. + +Let's recall the basic +approaches. + +There were iteration methods, +vector iteration methods, + +there were Sturm sequence +methods, there was the + +transformation method. + +And then, of course, there were + +polynomial iteration methods. + +So really, four classes +of methods that + +we are talking about. + +Each of them, we find, +have some advantages. + +Well, as engineer, surely we +want to now combine the + +advantages of each of these +methods to come up with + +optimum techniques for our +specific problems. + +Well, there are a number +of thoughts + +that we would go through. + +First of all, a determinant +search, a polynomial iteration + +method would be effective +to get near a root. + +Vector iteration then could +be used to calculate an + +eigenvalue and an eigenvector. + +The transformation method would +be good to orthogonalize + +the current iteration vectors +if we iterate with more than + +just one vector. + +And the Sturm sequence method +is extremely powerful to + +assure that we have actually +calculated the required + +eigenvalues and eigenvectors. + +Well, the first method then that +I would like to discuss + +with you is the determinant +search method. + +In this method, we have +combined some of these + +techniques that I pointed +out to you earlier + +in an optimum way. + +Here, we have the polynomial P +lambda, we want to, of course, + +solve for the roots of +that polynomial-- + +that is our objective. + +Here is lambda 1, there +is lambda 2. + +I also show a point, +A, because I will + +refer to it just now. + +The basic scheme in the +determinant search method is + +to look for the zeroes of +the determinant, of the + +determinant K minus mu I M. Of +course, these zeroes give us R + +equal to the eigenvalues. + +That's what we're interested +in calculating. + +Well, we are calculating +the determinant by the + +factorization of this matrix +into L D L transpose, and we + +notice that this determinant is +simply the product of the + +[? D I I's, ?] as I +mentioned earlier. + +Now, having a certain starting +value, mu 0, say, and mu 1. + +We can directly use the secant +iteration, that I mentioned to + +you earlier to get close +to an eigenvalue. + +Now, I also slipped in here +an acceleration factor. + +This acceleration factor would +be equal to 1 in the normal + +secant iteration that I showed +to you earlier already. + +However, since we want to use +this polynomial iteration + +technique only to get close to +an eigenvalue, and we might + +actually obtain with eta equal +to 1, sometimes slow + +convergence. + +What we do is we simply +set it larger to + +accelerate the process. + +And this is what we're +doing here. + +If we do jump beyond an +eigenvalue because we have + +accelerated the secant +iteration. + +In other words, if we do a jump +across here, then since + +we are factorizing the matrix +here, we can also look at the + +number of negative elements +in the D matrix. + +These would tell us that we, in +fact, have jumped across an + +unknown eigenvalue. + +So, in this particular case, of +course, there would be one + +negative element in +the D matrix. + +And we would know now we +have jumped across. + +The jumping across an unknown +eigenvalue is not possible + +when eta is equal to 1. + +However, it is possible when +eta is greater than 1. + +And however, that jumping +does not hurt us. + +In fact, all we will find is +that the Sturm sequence count + +will tell us that we have jumped +across an eigenvalue, + +and then, of course, we have to +go to another strategy of + +solving for the eigenvalue +more accurately. + +But the important point is that +all we want to do via + +this procedure is to get into +the vicinity of the + +eigenvalue. + +We do not want to calculate it +accurately, all we want to do + +is get into the vicinity of +an unknown eigenvalue. + +First, of course, lambda 1, +then lambda 2, and so on. + +There's also a concern, of +course, that we do not want to + +jump beyond A, because if we, in +our process of looking for + +lambda 1, we are jumping too +close to lambda 2, then via + +the other solution techniques +that we are using later on + +then to calculate the eigenvalue +more accurately, we + +would actually converge +to lambda 2. + +And, of course, that we +don't want, we want to + +calculate lambda 1. + +So, the process is then to start +off with eta equal to 1, + +iterate, see how we are +progressing towards an unknown + +eigenvalue. + +If that progressing is +very slow, we are + +choosing eta larger. + +There are specific strategies +that we're using to choose the + +right amount all eta. + +And until we find that we are +close to an eigenvalue, either + +from the left or we have jumped +across it already, but + +you should never +jumped to far. + +And we are making sure that we +never jump beyond that point + +A. and having jumped, we find +that the Sturm sequence count + +tells us about it. + +And now, we are going on to +another strategy, and that + +strategy is the vector +iteration, vector inverse + +iteration method that I +discussed with you earlier. + +What we are doing now, is we +have a new coefficient matrix, + +that's the one. + +We are sitting here, say, and +now I have assumed that we + +have, in fact, jumped. + +It's not necessary. + +We might have also approached +from this side and come very + +close to lambda J. And now, we +are using vector iteration to + +get this eigenvalue +accurately. + +This coefficient here, +or this value here + +corresponds to that length. + +And if you are adding this value +here to this shift, we + +are getting an approximation +to lambda J. And that, of + +course, is our objective. + +Once we have lambda J, we have +calculated this eigenvalue-- + +the eigenvector comes out, in x +k plus 1 as k increases, so + +we have calculated this eigen +pair, and now, of course, we + +would use deflation method, just +the way I showed it to + +your earlier, for the polynomial +iteration method. + +To deflate the polynomial of +this value, implicitly-- + +implicitly, that's important-- + +and we would continue our +iteration process towards that + +eigenvalue next. + +In this process, we also want +to make sure that the + +iteration vector is deflated +of the previously + +eigenvectors, for example, +Gram-Schmidt + +orthogonalization. + +If the convergence is slow in +this particular iteration + +here, we're using also the +really Rayleigh-quotient + +iteration to speed up +iteration itself. + +The advantage of the method-- +well, it calculates only the + +eigen pairs that are actually +required., there's no prior + +transformation of the +eigenprobelm necessary. + +The disadvantage of the method +is that we have to perform + +many triangular factorizations. + +Therefore, the method is really +only effective for + +small banded systems. + +If we want to calculate +eigenvalues of large banded + +systems, we really need +an algorithm with less + +factorizations, and more +vector iterations. + +And that is the subspace +iteration method. + +In fact, we have now extended +the subspace iteration method + +to be also most effective for +small banded systems. + +And I will just refer to +it very briefly later. + +The basic steps of the subspace +iteration method are + +the following. + +Here, we have the first +equation used. + +We have on the right +hand side, the + +current iteration vectors. + +Now, notice that in this +particular case, we're + +iterating with q vectors, +where q ip larger than p + +simultaneously. + +This gives us here, q right +hand side vector. + +We are solving for +q vectors here. + +This is an inverse iteration +step on q vector + +simultaneously. + +Then we are calculating the +projections of these k and m + +matrices on these vectors. + +Notice that this pat here, +of course, is equal to + +this right hand side. + +So we would not calculate +this here. + +We simply use the right hand +side, which we have evaluated + +already and plug it +right in there. + +But having calculated these two +matrices, which are now of + +order q by q, we are solving +eigenvalue problem all of + +these q by q matrices. + +And the solution of +that eigenvalue + +problem is shown here. + +Notice this matrix here +is a q by q matrix. + +We're using q vectors. + +This is a q by q matrix storing +the eigenvectors of + +this eigen problem here, of the +eigenproblem corresponding + +to these matrices. + +This here is the diagonal matrix +listing the eigenvalues + +of the eigenproblem + +corresponding to these matrices. + +Having calculated these matrices +here, and of course, + +that one too, we are performing +this operation to + +get a new set of iteration +vectors, which then are + +plugged back into here. + +Notice that the solution of +this eigenproblem, q by q, + +might be a 50x50 matrix here, +100x100 matrix, maybe a + +200x200, but that already would +be a large number of + +vectors if we're using-- + +a very large number +of vectors. + +This solution of this +eigenproblem can be + +effectively achieved via the +generalized Jacobi method, + +which I referred to +briefly earlier. + +Of course here, we are using +our solution algorithm for + +static analysis. + +There's L D L transpose +factorization involved here. + +And here, this is a simple +matrix multiplication that has + +to be carried out. + +This part here, is the +eigenproblem solution, and + +there's another vector + +multiplication carried out here. + +Now, under specific conditions, +this eigensolution + +algorithm converges and the +vectors stored in x k plus 1, + +they are q vectors now here, +with appropriate ordering, + +converge to the phi matrix. + +This is now an n by q matrix, +storing the lowest + +eigenvectorr, or I should +say, the q eigenvectors + +corresponding to the +lowest eigenvalues. + +And here, we have it written +out, and of course, this is a + +diagonal matrix. + +The condition that we have to +satisfy here is that the + +starting subspace spanned by +these vectors here must not be + +orthogonal to the subspace +spanned by the p eigenvectors + +that we are interested in. + +Of course, here, I'm talking +about q eigenvectors. + +I really am only interested in +p eigenvectors, in the lowest + +p eigenvectors. + +So in general, what happens is +that I will only be interested + +in these eigenvectors here, and +the lowest eigenvalues. + +One comes out here, I'm not +too much concerned about. + +In fact, we are carrying these +along only to accelerate the + +iteration scheme. + +And I will show you just know +what the convergence rate is, + +and why we are carrying +them along. + +So since we only interested in +the lowest p eigenvalues and + +corresponding eigenvectors, +we want to get convergence + +towards those, and what that +means is that our starting + +vectors in here must not be m +orthogonal to the eigenvectors + +that we want to calculate, +phi 1 to phi p. + +If that condition is satisfied, +one can show, + +theoretically, and of course, +we see it in practice also, + +that this iteration scheme will +always converge to the + +lowest eigenvectors and +corresponding eigenvalues. + +One important point here, once +we have calculated, say, a + +certain number of iteration +vectors, and we have tested + +for convergence, we are saying +that convergence is reached, + +say, when the current iterates +on the eigenvalues don't + +change very much anymore. + +This tol might be 10 to the +minus 6, as an example. + +Then once this condition is +satisfied, we stop the + +iteration, and we really want +to make then sure that we + +really converge to the +eigenvalues of interest. + +And how is that accomplished? + +Well, if these are the +p eigenvalues, we are + +calculating error bounds on +these eigenvalues, indicated + +here by the blue lines here. + +And then just to the right +of the error bound. + +Or we can really use that error +bound, we apply a Sturm + +sequence shift, mu S. What this +then says that k minus mu + +S factorize into L +D L transpose. + +And we must now have in the D +matrix, p negative elements. + +And only p, not more, not less, +just p negative elements + +must be occurring +in the D matrix. + +This check is absolutely sure. + +If this check a satisfied, we +can be absolutely sure that we + +have calculated the eigenvalues +of interest, the + +lowest p eigenvalues, in +this particular case. + +So I repeat, after we have +satisfied this convergence + +rate, or this conversions +limit, I should say-- + +typically 10 to the minus +6, or 10 to the minus 8, + +depending on what accuracy +you want. + +We calculating eigenvalue +bounds, as shown here. + +We are putting a mu S Sturm +sequence shift just to the + +right of the last eigenvalue +bound, and if this is the p's + +eigenvalue, we must have +here, exactly p + +negative elements indeed. + +The convergence rate of the +iteration, we find is given by + +lambda i divided by +lambda q plus 1. + +And the convergence rate to the +eigenvalues of interest + +are just this value squared. + +Notice that we have +here, q plus 1. + +So if we are interested in the +p's eigenvalue,== the black + +pen doesn't work too well, let +me take the blue one here-- + +if you're interested in the p's +eigenvalue as the largest + +eigenvalue, notice that the +convergence rate is that + +lambda p plus-- lambda p divided +by lambda q plus 1. + +That is the worst convergence +rate that we are reaching + +because the other eigenvalues +below lambda p are smaller, + +giving us better convergence +rate. + +So this is the worst that we +can reach, if we are only + +interested in p eigenvalues +and corresponding + +eigenvectors. + +Notice however, that lambda +q plus 1 must be + +greater than lambda p. + +If lambda q plus 1 is +equal to lambda p, + +we would never converge. + +So this is the reason why we +are choosing q to be larger + +than p, substantially +large than p. + +For example, we might choose +q to be typically, as an + +example, q being the maximum +of 2p and p plus 8. + +This is a formula that +we have used with + +quite a lot of success. + +In other words, when p is equal +to 4, we would use-- + +no, sorry, I should say +the minimum here. + +the In other words, when +p is equal to 4, we + +would have 8 here. + +When p is equal to +8, it's the same. + +Because these two values +give us the same. + +And when p is equal to 100, +then we just have 8 more. + +Q is equal to 108. + +This 8 here is a safeguard, so +that this cannot be equal to 1 + +in practice. + +It would only be equal to 1 if +we would have, basically. + +9 time the same root, and of +course, that is a case which + +we would hardly encounter +in practice. + +Now, regarding the choice +of the starting values. + +For the vectors, there +are two choices. + +x1 is simply a vector +with 1 only. + +xj would be a vector with zeroes +everywhere, but with a + +1 somewhere. + +And that one is in +the j's entry-- + +sorry, the k's entry. + +The k's entry for ek, ek has +in the case, entry of 1. + +And otherwise, everywhere +zeroes. + +This would be the second to +the q minus first vector. + +And the last vector, we +take a random vector. + +That is one choice of +starting vectors. + +The Lanczos method can also be +used to generate starting + +vectors very effectively. + +Once we have selected the +starting vector, we go through + +the iteration schemes the way +I have been displaying it. + +And there, it is important, once +again, to perform after + +the convergence- the Sturm +system sequence check, and + +also we might want to calculate +error bounds on the + +eigenvalues and eigenvectors. + +These error bounds would be +calculated by simply saying, + +well, if we want to satisfy-- + +or if we want to solve for +lambdas and phis that + +satisfies this equation, +then why not see how + +close we will satisfy. + +Make that a minus and put here +an error, say, R, on + +the right hand side. + +Substituting then the last +values for lambda and phi that + +we just kind calculated, the +last iterative values, we get + +this top line here. + +We're taking a norm +the way I've been + +talking about earlier. + +And we are also taking a norm +at the bottom to get, + +basically, a relative value, +top to bottom. + +And then relative value +gives us epsilon i. + +So epsilon i should be of order, +10 to the minus 3, if + +we want to have three-digit +accuracy in the eigenvalues + +and eigenvectors. + +In fact, the eigenvalues will +generally be more accurate + +than the eigenvectors. + +That is, of course, a +very low accuracy. + +Ideally, we have much +more accuracy after + +the iteration schemes. + +We would have to tighten the +tolerance, the tol value that + +I referred to earlier +sufficiently to make epsilon i + +small enough. + +Now, I like to refer, very +briefly also, to an + +accelerated subspace iteration +method that we have been + +developing during the last +years, which is a very + +substantial extension of this +subspace iteration method. + +The idea here is, basically, +that we wanted to combine the + +sum of the effective techniques +that we are using + +in the polynomial iteration +method, with the standard + +subspace iteration method +that I have + +discussed with you here. + +Basically, in the accelerated +subspace iteration method, we + +are not keeping a constant +coefficient matrix, as + +we have done here. + +The k matrix never changed. + +Here, we are shifting the +coefficient matrix, we are + +shifting through the spectrum. + +Much in the same way as we are +pursuing it in the determined + +search method. + +And that is number one. + +And number two-- we are also +not iterating with vectors + +that are always larger than +the number of eigenvectors + +that we want to calculated. + +In fact, if we want to +calculate, say, 100 + +eigenvalues, we might just use +four iteration vectors at a + +time, and shift through the +spectrum, always with four + +iteration vectors, capturing +the eigenvalues values and + +eigenvectors that we are really + +interested in, in bundles. + +So this is a way how we have +very substantially accelerated + +the standard subspace iteration +method that I have + +been talking to you +about just now. + +If you are interested in seeing +some solution times, + +please we look at +this reference. + +Ladies and gentlemen, this +then brings me to the + +conclusion of this lecture. + +And in fact, it also brings us +to the conclusion of the whole + +set of lectures that I have +been presenting to you. + +These set up lectures have been +brief and very compact. + +They've been a survey +introduction to the finite + +element method-- + +a very brief and compact +introduction and survey. + +Brief because there are +only 12 lectures. + +Compact because I wanted to +present to you as much as + +possible in these 12 lectures. + +And there is, of course, a lot +of information that we could + +have talked about. + +However, I hope that the +information that I had given + +in the lectures has been of +interest to you, and it will + +also be valuable to you in your +work and general decision + +making process of whether you +want to use a finite element + +method, how you want to +use it, and so on. + +I like to take the opportunity +at this point to thank the + +Center of Advanced Engineering +Studies for the terrific + +effort they've made in +preparing the tapes. + +I'm very happy that they have +been cooperative with me in + +the way they did, in the +preparation of the tapes. + +I also would like to thank you +as listeners for your patience + +of listening to the tapes and, +once again, I hope you found + +the tapes interesting and +have obtained some value + +information on them. + +Best of luck in your further +studies of the + +finite element method. \ No newline at end of file diff --git a/exav1FKMfbw.txt b/exav1FKMfbw.txt new file mode 100644 index 0000000000000000000000000000000000000000..82a6dc44d8bfecd358ea4d2ece1e876b62c8063a --- /dev/null +++ b/exav1FKMfbw.txt @@ -0,0 +1,699 @@ +align:start position:0% + +let's go ahead and start our the first + + align:start position:0% +let's go ahead and start our the first + + + align:start position:0% +let's go ahead and start our the first +thing you'll see in the our console is + + align:start position:0% +thing you'll see in the our console is + + + align:start position:0% +thing you'll see in the our console is +the version of our you are using in + + align:start position:0% +the version of our you are using in + + + align:start position:0% +the version of our you are using in +other basic information related to + + align:start position:0% +other basic information related to + + + align:start position:0% +other basic information related to +licensing citations and demos to clear + + align:start position:0% +licensing citations and demos to clear + + + align:start position:0% +licensing citations and demos to clear +the console you can simply go to edit + + align:start position:0% +the console you can simply go to edit + + + align:start position:0% +the console you can simply go to edit +and select clear console we'll start by + + align:start position:0% +and select clear console we'll start by + + + align:start position:0% +and select clear console we'll start by +reading in our data set + + align:start position:0% +reading in our data set + + + align:start position:0% +reading in our data set +USDA dot CSV which contains all foods in + + align:start position:0% +USDA dot CSV which contains all foods in + + + align:start position:0% +USDA dot CSV which contains all foods in +the USDA database in 100 gram amounts + + align:start position:0% +the USDA database in 100 gram amounts + + + align:start position:0% +the USDA database in 100 gram amounts +you should have already downloaded the + + align:start position:0% +you should have already downloaded the + + + align:start position:0% +you should have already downloaded the +data set to your computer to be able to + + align:start position:0% +data set to your computer to be able to + + + align:start position:0% +data set to your computer to be able to +read the data set in our we first need + + align:start position:0% +read the data set in our we first need + + + align:start position:0% +read the data set in our we first need +to navigate to the directory in our + + align:start position:0% +to navigate to the directory in our + + + align:start position:0% +to navigate to the directory in our +computer where the data file USDA dot + + align:start position:0% +computer where the data file USDA dot + + + align:start position:0% +computer where the data file USDA dot +CSV is saved to do so if you are on a + + align:start position:0% +CSV is saved to do so if you are on a + + + align:start position:0% +CSV is saved to do so if you are on a +Mac go to the miscellaneous menu and + + align:start position:0% +Mac go to the miscellaneous menu and + + + align:start position:0% +Mac go to the miscellaneous menu and +select change working directory if you + + align:start position:0% +select change working directory if you + + + align:start position:0% +select change working directory if you +are on a PC go to the file menu select + + align:start position:0% +are on a PC go to the file menu select + + + align:start position:0% +are on a PC go to the file menu select +change directory and then navigate to + + align:start position:0% +change directory and then navigate to + + + align:start position:0% +change directory and then navigate to +the folder where you save the CSV file + + align:start position:0% +the folder where you save the CSV file + + + align:start position:0% +the folder where you save the CSV file +then press ok nothing has happened in + + align:start position:0% +then press ok nothing has happened in + + + align:start position:0% +then press ok nothing has happened in +our until now except changing the + + align:start position:0% +our until now except changing the + + + align:start position:0% +our until now except changing the +working directory to double check that + + align:start position:0% +working directory to double check that + + + align:start position:0% +working directory to double check that +we are in the right working directory we + + align:start position:0% +we are in the right working directory we + + + align:start position:0% +we are in the right working directory we +can type get WD which stands for get + + align:start position:0% +can type get WD which stands for get + + + align:start position:0% +can type get WD which stands for get +working directory and then our gives us + + align:start position:0% +working directory and then our gives us + + + align:start position:0% +working directory and then our gives us +the path to the folder we just selected + + align:start position:0% +the path to the folder we just selected + + + align:start position:0% +the path to the folder we just selected +now we should be ready to read in our + + align:start position:0% +now we should be ready to read in our + + + align:start position:0% +now we should be ready to read in our +data set we will use the function read + + align:start position:0% +data set we will use the function read + + + align:start position:0% +data set we will use the function read +CSV since the data set was given to us + + align:start position:0% +CSV since the data set was given to us + + + align:start position:0% +CSV since the data set was given to us +in a CSV format and let's save the + + align:start position:0% +in a CSV format and let's save the + + + align:start position:0% +in a CSV format and let's save the +output to a data frame and call it USDA + + align:start position:0% +output to a data frame and call it USDA + + + align:start position:0% +output to a data frame and call it USDA +and this is equal to read CSV and this + + align:start position:0% +and this is equal to read CSV and this + + + align:start position:0% +and this is equal to read CSV and this +takes has an input the name of the CSV + + align:start position:0% +takes has an input the name of the CSV + + + align:start position:0% +takes has an input the name of the CSV +file which is USDA dot CSV and don't + + align:start position:0% +file which is USDA dot CSV and don't + + + align:start position:0% +file which is USDA dot CSV and don't +forget the quotation marks around the + + align:start position:0% +forget the quotation marks around the + + + align:start position:0% +forget the quotation marks around the +name of the CSV file pressing enter are + + align:start position:0% +name of the CSV file pressing enter are + + + align:start position:0% +name of the CSV file pressing enter are +now read the information from the data + + align:start position:0% +now read the information from the data + + + align:start position:0% +now read the information from the data +set and saved it to the data frame USDA + + align:start position:0% +set and saved it to the data frame USDA + + + align:start position:0% +set and saved it to the data frame USDA +now it's time to learn about our data we + + align:start position:0% +now it's time to learn about our data we + + + align:start position:0% +now it's time to learn about our data we +can use the structure function or STR + + align:start position:0% +can use the structure function or STR + + + align:start position:0% +can use the structure function or STR +and R and give it the input USDA this + + align:start position:0% +and R and give it the input USDA this + + + align:start position:0% +and R and give it the input USDA this +gives us the following information we + + align:start position:0% +gives us the following information we + + + align:start position:0% +gives us the following information we +have 7000 58 observations or Foods in + + align:start position:0% +have 7000 58 observations or Foods in + + + align:start position:0% +have 7000 58 observations or Foods in +our data set along with 16 different + + align:start position:0% +our data set along with 16 different + + + align:start position:0% +our data set along with 16 different +variables the first bear + + align:start position:0% +variables the first bear + + + align:start position:0% +variables the first bear +gives a unique identification number for + + align:start position:0% +gives a unique identification number for + + + align:start position:0% +gives a unique identification number for +each of the food starting with the + + align:start position:0% +each of the food starting with the + + + align:start position:0% +each of the food starting with the +number 1001 the second variable gives a + + align:start position:0% +number 1001 the second variable gives a + + + align:start position:0% +number 1001 the second variable gives a +text description of each of the foods + + align:start position:0% +text description of each of the foods + + + align:start position:0% +text description of each of the foods +the third variable is the amount of + + align:start position:0% +the third variable is the amount of + + + align:start position:0% +the third variable is the amount of +calories and 100 grams of these foods + + align:start position:0% +calories and 100 grams of these foods + + + align:start position:0% +calories and 100 grams of these foods +and it's given to us in kilocalories + + align:start position:0% +and it's given to us in kilocalories + + + align:start position:0% +and it's given to us in kilocalories +then we also have information about the + + align:start position:0% +then we also have information about the + + + align:start position:0% +then we also have information about the +protein total fat carbohydrate saturated + + align:start position:0% +protein total fat carbohydrate saturated + + + align:start position:0% +protein total fat carbohydrate saturated +fat and sugar levels in grams as well as + + align:start position:0% +fat and sugar levels in grams as well as + + + align:start position:0% +fat and sugar levels in grams as well as +the sodium cholesterol calcium iron + + align:start position:0% +the sodium cholesterol calcium iron + + + align:start position:0% +the sodium cholesterol calcium iron +potassium and vitamin C levels in + + align:start position:0% +potassium and vitamin C levels in + + + align:start position:0% +potassium and vitamin C levels in +milligrams and finally the amount of + + align:start position:0% +milligrams and finally the amount of + + + align:start position:0% +milligrams and finally the amount of +vitamin E and vitamin D in what is known + + align:start position:0% +vitamin E and vitamin D in what is known + + + align:start position:0% +vitamin E and vitamin D in what is known +as international units and this is a + + align:start position:0% +as international units and this is a + + + align:start position:0% +as international units and this is a +standard measurement for drugs in + + align:start position:0% +standard measurement for drugs in + + + align:start position:0% +standard measurement for drugs in +vitamins now to obtain high level + + align:start position:0% +vitamins now to obtain high level + + + align:start position:0% +vitamins now to obtain high level +statistical information about our + + align:start position:0% +statistical information about our + + + align:start position:0% +statistical information about our +dataset we can use the summary function + + align:start position:0% +dataset we can use the summary function + + + align:start position:0% +dataset we can use the summary function +and give it as an input the USDA data + + align:start position:0% +and give it as an input the USDA data + + + align:start position:0% +and give it as an input the USDA data +frame the summary function gives us + + align:start position:0% +frame the summary function gives us + + + align:start position:0% +frame the summary function gives us +information such as the minimum the + + align:start position:0% +information such as the minimum the + + + align:start position:0% +information such as the minimum the +maximum and the mean values across all + + align:start position:0% +maximum and the mean values across all + + + align:start position:0% +maximum and the mean values across all +seven thousand and fifty-eight foods for + + align:start position:0% +seven thousand and fifty-eight foods for + + + align:start position:0% +seven thousand and fifty-eight foods for +each of the 16 different variables for + + align:start position:0% +each of the 16 different variables for + + + align:start position:0% +each of the 16 different variables for +instance the maximum amount of + + align:start position:0% +instance the maximum amount of + + + align:start position:0% +instance the maximum amount of +cholesterol is 3100 milligrams + + align:start position:0% +cholesterol is 3100 milligrams + + + align:start position:0% +cholesterol is 3100 milligrams +whereas the mean is only 41 point 55 + + align:start position:0% +whereas the mean is only 41 point 55 + + + align:start position:0% +whereas the mean is only 41 point 55 +milligrams we also have information + + align:start position:0% +milligrams we also have information + + + align:start position:0% +milligrams we also have information +about the number of non-available + + align:start position:0% +about the number of non-available + + + align:start position:0% +about the number of non-available +entries for instance we have 1910 foods + + align:start position:0% +entries for instance we have 1910 foods + + + align:start position:0% +entries for instance we have 1910 foods +that are missing entries for their sugar + + align:start position:0% +that are missing entries for their sugar + + + align:start position:0% +that are missing entries for their sugar +levels now scrolling through this + + align:start position:0% +levels now scrolling through this + + + align:start position:0% +levels now scrolling through this +information a startling observation is + + align:start position:0% +information a startling observation is + + + align:start position:0% +information a startling observation is +the maximum level of sodium which is 38 + + align:start position:0% +the maximum level of sodium which is 38 + + + align:start position:0% +the maximum level of sodium which is 38 +thousand seven hundred and fifty eight + + align:start position:0% +thousand seven hundred and fifty eight + + + align:start position:0% +thousand seven hundred and fifty eight +milligrams this number is huge given + + align:start position:0% +milligrams this number is huge given + + + align:start position:0% +milligrams this number is huge given +that the daily recommended maximum is + + align:start position:0% +that the daily recommended maximum is + + + align:start position:0% +that the daily recommended maximum is +only 2300 milligrams let's investigate + + align:start position:0% +only 2300 milligrams let's investigate + + + align:start position:0% +only 2300 milligrams let's investigate +this variable further in our next video + + align:start position:0% + + + + align:start position:0% + +you \ No newline at end of file diff --git a/fFg4uXMpnV0.txt b/fFg4uXMpnV0.txt new file mode 100644 index 0000000000000000000000000000000000000000..105766df918b2b578914f21d11dfb292c99c8c3b --- /dev/null +++ b/fFg4uXMpnV0.txt @@ -0,0 +1,2356 @@ +The following content is +provided under a Creative + +Commons License. + +Your support will help MIT +OpenCourseWare continue to + +offer high-quality educational +resources for free. + +To make a donation, or view +additional materials from + +hundreds of MIT courses, visit +MIT OpenCourseWare at + +ocw.mit.edu. + +PROFESSOR: OK, OK, +Settle down. + +Settle down. + +It's 11:05. + +It's time to learn. + +All right. + +Last day we were looking at the +emissions spectrum of the + +target in the x-ray tube. + +The target is the anode, and +it's being a bombarded by + +electrons that have been +accelerated across a potential + +difference of some tens of +thousands of volts, and this + +was what we saw as the output, +intensity versus wavelength. + +We see this whale shaped curve +which we have attributed to + +bremsstrahlung, which is +the breaking radiation. + +And then if the voltage +is high enough, high + +enough to do what? + +High enough to eject inner shell +electrons, we will get + +the cascade, and the cascade +will give rise to specific + +values of wavelength associated +with transitions + +within the target atom. + +There's too much talking. + +I want it absolutely silent or +else somebody is going to + +leave. That's the only +way it works here. + +I talk. + +You listen. + +And if you have a problem with +that, there's a door here. + +There's a door there. + +And there's a door +at the back. + +So let's get it straight +right now. + +It's the only way +it works here. + +Now what happens is that these +characteristic lines are + +calculable in part. + +The K alpha line, the L alpha +line we saw from Moseley's + +law, which is up here +on the slide. + +and the leading edge of the +whale shape curve, the + +bremsstrahlung is calculable +by the Duane-Hunt Law. + +The rest of this is +not calculable. + +So there it is. + +What I want to do today is +harness this radiation. + +The reason we were studying +x-rays in first place was that + +we said they had a length scale +that was comparable to + +that of atomic dimensions. + +And so now we want to close +the circle here and probe + +atomic arrangement by +x-ray diffraction. + +And it goes by this +three-letter + +initialization XRD. + +And in order to use x-ray +diffraction to probe atomic + +structure, we're going to +make another model. + +And this model is going +to be simple. + +And it's going to be inaccurate, +but it's going to + +be good enough to explain +the phenomena that + +we're going to study. + +So the first thing I want to +do in constructing a model + +that will allow to use x-ray +diffraction, is to model the + +atoms as mirrors. + +That's the first assumption +that we make. + +We model the atoms as mirrors. + +And when we model the atoms as +mirrors, this means that we + +will invoke the laws of +specular reflection. + +So if this table top is a plane +of atoms, and I have a + +beam coming down at an angle, +the laws of specular + +reflection say that the angle +of incidence will equal the + +angle of reflection. + +So that's all we're doing by +modeling the atoms as mirrors. + +Laws of speculative +reflection apply. + +So that simply means that the +angle of incidence, theta + +incidence equals theta +reflection. + +And you'll see how that comes +into play in a minute. + +And then the second thing we're +going to do in order to + +get intensities is to use the +concept of constructive and + +destructive interference. + +OK. + +So we apply interference +criteria. + +And I will explain what +that means in a + +second with a diagram. + +But in dense text, it simply +means that in phase rays-- + +it sounds like this rain in +Spain falls mainly in the + +plain-- in-phase rays amplify. + +And out-of-phase rays dampen. + +So at some point, you'll study +this in physics, but we need + +it right now, so I'll give you a +little bit of foreshadowing, + +and then you'll be ahead +of the game when you + +meet this in physics. + +So what I'm going to do is I'm +going to show you two rays, + +and they both have the +same wavelength. + +And I want to show +you in phase. + +And so I want to illustrate this +concept here, in-phase + +rays amplify. + +So let's give one ray here. + +I'm going to depict it as +a wave. All right, so + +that's ray number 1. + +And beneath it, is +ray number 2. + +It's got the same wavelength. + +So that means crest-to-crest +distance is the same, and if + +it's in phase, in phase means +that crest lines up with + +crest, trough lines +up with trough. + +So I'm going to make another +one seemingly identical. + +It's supposed to be identical +to the capacity of + +my ability to draw. + +And so what this means is +that these will amplify. + +So 1 plus 2, 1 plus 2 will +give me something + +that looks like this. + +I'm going to line it up again. + +Only now the amplitude is double +the amplitude of a + +single ray. + +That's what I'm trying +to depict here. + +OK. + +So this is amplification. + +Now over here, I want to +do the same thing. + +Only I'm going to have +two rays, same + +wavelength, but out of phase. + +OK, so in phase is here, out +of phase is to the right. + +So we'll have ray number +3, which does this. + +And ray number 4, I'm going to +line up with the crest of ray + +number 3, the trough of ray +number 4, but it's going to be + +the same wavelength. + +So the distance between +successive crests is the same. + +Only they're going to be +offset by exactly half + +wavelength. + +So the crest here of wave +3 lines up with the + +trough of wave 4. + +The trough of wave 3 lines up +with the crest of wave 4, and + +so on, and so on, and so on. + +And if I drew this thing +accurately, it would be + +obvious to you. + +But since I can't draw very +well, then we're going + +to take 3 plus 4. + +And the sum of the crest +and the trough is 0. + +The sum of the trough +and the crest is 0. + +And so the sum here is 0. + +All right this is total +destruction. + +This is cancellation. + +So in the extreme, you can have +destructive interference + +that dampens to the point +of obliteration. + +OK, so that's the two extremes, +full amplification + +and complete cancellation. + +So now, I want to take this +concept of planes as mirrors + +and rules of interference +criteria, and now what I want + +to do is illuminate. + +And I want to use the +full board here. + +So here's what we're +going to do. + +We're going to take in +phase, coherent-- + +that's what coherent means. + +Coherent means that the +radiation is in phase and + +monochromatic. + +What's that mean? + +Monochromatic means one color, +which means single wavelength. + +So I have something of a single +wavelength in phase. + +Coherent, monochromatic, +incident radiation, so I've + +got a plurality of rays. + +I have this thing flooded +by a beam. + +So what I'm going to +do, is I'm going to + +draw some atoms here. + +And I'll put a second +batch on top. + +And now I'm going to model +these as mirrors. + +So I'm going to have the +incident beam come in like so. + +The incident beam comes in like +so at an angle theta. + +So this is theta incident. + +This is the angle +of incidence. + +And according to our model, the +beam is reflected at the + +same angle. + +So this is theta, reflection +of theta. + +Reflection equals +theta incidence. + +So that's the first +thing that we do. + +And then the second thing we +do, is we use the laws of + +interference. + +So I'm going to take a second +beam, and it's going to go + +down to this atom here. + +So I'm going to bring +it down like so. + +And it's going to come +in at the same angle. + +And it's going to leave +at the same angle. + +And if you'll excuse +the drawing, these + +lines should be parallel. + +They should be coming in +parallel, and they should be + +leaving parallel where these +angles theta i and + +theta r are the same. + +Now how do we invoke the +interference criteria? + +Well what I'm going to do +is put a marker here. + +I'll put a marker. + +And I'll call the first one ray +number 1, and the second + +one ray number 2. + +And what I'm going to show is if +I start from ray number 1-- + +maybe it's time for +colored chalk-- + +so if I start from ray number 1, +to show that it's in phase + +with ray number 2, I'm going to +draw this little waveform, + +and they're both lined up. + +So you can see crest lines up +with crest. Trough lines up + +with trough, and they both +have the same wavelength. + +So that makes the point +coherent, monochromatic. + +But now things get interesting, +because you can + +see that ray number 1 travels +a shorter distance than ray + +number 2, and we can put on some +coordinates here and mark + +the geometry, so we can say that +the point at which the + +ray number 2 has to start +traveling a longer distance, + +I'll drop a normal down, +and I'm going to + +call this point A. + +This is point A. + +The bottom here is point B. + +And then up here where it +catches up with ray number 1, + +the reflected ray number +1, I'm going to + +call this point C. + +So you can you can see that +ray number 2 has to travel + +this extra distance, +AB plus BC. + +And now, if I want to get out +to here where I'm now in the + +reflected zone, and I want ray +number 1 reflected and ray + +number 2 reflected to continue +to be in phase, there's a + +geometric constraint on +the dimension of AB + +plus BC, isn't there? + +That length, AB plus BC must +be a whole number of + +wavelengths. + +It must be an integer number +of wavelengths of whatever + +this thing is, otherwise, +these two will + +not being in phase. + +So that's the interference +criterion. + +And n can equal 1, 2, 3, and so +on, so this is called the + +order of reflection. + +And then we can go through +the trigonometry. + +I'm not going to +do it in class. + +It's just a waste of time. + +It'll bore everybody to tears. + +But if you want to do that at +home at some point when you've + +got nothing to do, you +can go through. + +You've got all the +numbers here. + +You know the value of lambda. + +You know the distance AB, +and you know what + +this distance is. + +This distance between successive +planes is your + +dhkl, isn't it? + +So if you go through all of this +analysis, you will show + +that n lambda is equal to 2 +times the d of the hkl spacing + +times the sign of theta. + +And this is called +Bragg's Law. + +And Bragg's Law governs the +reflection of incident + +radiation by a crystal. + +Now you'll notice I didn't +put an apostrophe here. + +Some people put the apostrophe +here, because the + +man's name was Bragg. + +Some people put the apostrophe +here because, in fact, it was + +father and son. + +And they both together won +the Nobel Prize in 1915. + +Now there have been people who +lived to see, as Nobel Prize + +winners, one of their children +win the Nobel Prize. but this + +is the only time in history a +father and son team together + +won the Nobel Prize +for the same work. + +And there are undoubtedly people +sitting in this room + +who think the fact that the +father and son could work + +together in physics for an +extended period of time alone + +is deserving of the +Nobel Prize. + +Now in 3.091, I'm going to keep +it simple, always choose + +first order reflection, always +n equals 1 in Bragg's Law. + +So therefore, we will write +Bragg's Law as lambda equals + +2d sin theta. + +And to make the point, the d +is specific to a particular + +set of planes. + +So it's a d spacing +of the hkl planes. + +And it's the theta associated +with the correct reflection of + +the hkl planes. + +Now how does destructive +interference come into play? + +Destructive interference comes +into play should there be a + +situation where I have +a third ray. + +I'm going to bring a third +ray in also at the + +same angle of incidence. + +And that ray is halfway between +these two rays. + +And what situation +could that be? + +That could be a situation in +which the crystal structure + +has in a plane out from the +board, an atom that sits + +halfway between these +other two atoms. + +And if that happens, +you can see. + +We can go through +the derivation. + +But there's going to be a path +length difference that's + +exactly 1/2 wavelength +different. + +That's bad. + +It's not just there's going to +be some measure of reduction. + +It's going to be total +cancellation. + +And so by going through the set +of crystal structures and + +recognizing that when you have +1/2 wavelength difference, you + +get destructive interference. + +And therefore, you +will see no line. + +The incident radiation will come +in at this angle, and at + +the reflection angle for that +particular plane, there will + +be nothing detected. + +So you can say that you have a +combination of selection rules + +that involve the integral of +both the rules of interference + +and interaction with the +crystal structure. + +So let's generalize this and +say if we take interference + +criteria plus the crystal +structure, that is to say, the + +instant relationship of atom +positions for a particular + +specimen, the combination of +that will give rise to the set + +of expected reflections. + +So only when you satisfy the +Bragg criterion do you get + +reflection. + +So you move the specimen. + +And only at that special angle +will you get the reflections, + +will you get constructive +interference. + +So this, in fact, is +a fingerprint. + +This is a fingerprint +of the crystal. + +In this case, we're not getting +the chemical identity. + +We're getting the structural +identity. + +So we can determine +if something is + +BCC, FCC, and so on. + +So for example in BCC, that's +exactly the case that I just + +illustrated. + +So in BCC we have atoms +at the eight corners. + +And we have an atom +dead center. + +There's a central atom. + +And the central atom lies in +0 0 2 plane, doesn't it? + +The base of this is 0 0 1. + +And the top is an 0 0 1. + +But the central atom +is an 0 0 2. + +And 0 0 2 is halfway between +successive 0 0 1. + +So can you see that light +that comes in? + +And it's going to be +constructively reinforced. + +Off of 0 0 1 is going to be +destructively reinforced off + +of 0 0 2, and the result is +that in BCC, no 0 0 1 + +reflection observed. + +The same thing happens in face +centered cubic, right? + +What's the face of face centered +cubic look like? + +It looks like this, +doesn't it? + +So there's an 0 0 1. + +Here's an 0 0 1. + +What about this space +centered atom? + +Where is it? + +That's an 0 0 2. + +It's halfway between 0 0 1. + +So at the angle where you +would've expected, if you use + +the Bragg Law and calculate the +angle at which for your + +particular crystal, because +you know the d spacing. + +You fix the wavelength +of your x-radiation + +coming out of the generator. + +At the angle where you would +expect to see reflection off + +of 0 0 1, you will see nothing, +because 0 0 2 is + +canceling 0 0 1. + +So you don't have to worry +about all this. + +This has all been tabulated +for you. + +Somebody has gone through +and done all of this. + +Well, this is just +making the point. + +See, there's a simple cubic. + +All the planes are reflecting. + +There's body-centered cubic. + +That's a/2. + +There's face-centered +cubic a/2. + +0 0 2 is going to +cancel 0 0 1. + +You're not going to see +anything there. + +So people have gone through. + +And they've made this set +of rules for reflection. + +So simple cubic, you +get reflection + +from all the planes. + +Body-centered cubic, you just +get these planes here. + +And it turns out that there's +a simple rule that compactly + +represents which planes are +going to reflect in + +body-centered cubic. + +And in BCC, the hkl, it's the +planes for which h plus k plus + +l is an even number. + +h plus k plus l is even. + +And 0 was counted as even. + +So for example, 0 0 1 h +plus k plus l is 1. + +It doesn't reflect. + +0 0 2, 0 plus 0 plus 2 is 2. + +It does reflect. + +And so on. + +You just go down +the whole line. + +And so these are in ascending +order of h squared plus k + +squared plus l squared, because +that's a nice way of + +deciding how to add them up. + +And now in FCC the +selection rule is + +a little bit different. + +In FCC you get reflection from +planes when you write the HKL + +such that h, k, and l must be +either all even numbers, or + +all odd numbers, or some people +like to say unmixed. + +Some crystallographers say +unmixed, meaning you can't + +have a combination of even +numbers and odd number. + +So for example, 0 0 1 won't +work because 0 is a zero. + +That's even. + +1 is odd. + +But 0 0 2, h plus k plus l all +even or all odd, there you go + +all even or all odd unmixed. + +So this will work. + +And then so on. + +So you can go through and +see which ones work. + +All right. + +So the next one here +is in the sequence. + +This sums to 1. + +And what would sum to 2? + +It would be 0 1 1. + +And 0 1 1 doesn't work either +because zero is even. + +And 1 is odd. + +The next one of the +sequence is 1 1 1. + +These are all odd. + +So that one reflects. + +So in FCC, you don't +see 0 0 1, 0 1 1. + +But 1 1 1 does reflect. + +And then 0 0 2, which is the +next one, because 0 squared + +plus 0 squared plus +2 squared is 4. + +This is even even. + +So that one works. + +So there's the sequence. + +And so now what we can do is use +this technique in order to + +make measurements. + +But before we do so, I want to +show you the experimental + +measurement, one way. + +There's several ways of +conducting the measurement. + +And so the first way I'm going +to show you is called + +diffractometry. + +And you can do this over +in Building 13. + +If you get yourself a UROP, you +might be assigned to make + +some measurements. + +So diffractometry is a form +of x-ray diffraction. + +It's one of the techniques. + +And the way it works is you fix +the wavelength and vary + +the angle of incidence, +you don't + +rotate the x-ray generator. + +You rotate specimen and present +continually varying + +angles to the thing. + +So this shows the technique +in operation. + +So you have a specimen +sitting here. + +The specimen can either be +a thin film, or in other + +instances, we have a finely +ground powder. + +So each of the powder grains +presents a different angle. + +And coming out of the +collimator is the + +monochromatic. + +We want a single wavelength. + +So this collimator means it's +monochromatic and coherent. + +So that beam comes and +strikes the specimen. + +And for historical reasons, +instead of calling this the + +angle of incidence, and this the +angle of reflection, they + +call the angle that goes to +the detector 2 theta. + +In other words, the projection +of the beam, this is theta + +incident equals theta r. + +So this is really 2 +theta incident, or + +it's 2 theta reflected. + +It's the same thing. + +So you'll see x-ray data +usually reported + +in units of 2 theta. + +And here's the detector. + +And then all you do is you +rotate the specimen. + +And by rotating the specimen +with a detector, you're able + +to get the entire set +of reflections. + +And whenever you move through +an angle that satisfies the + +Bragg Law, you get a +peak in intensity. + +And here's what the output +would look like. + +So you're plotting intensity +as a function of 2 theta. + +So somewhere along here at +around, it looks like about 38 + +degrees, you have satisfied the +Bragg angle, and you get + +constructive interference. + +When you move off of 38 +degrees, destructive + +interference reigns supreme, +and you get almost no + +reflection. + +Then you get to the right +angle for 2 0 0, you get + +reflection. + +Well, all you get +is these lines. + +You don't get these numbers. + +These numbers you don't +get for free. + +So here's the experiment +that we're going to do. + +We're going to run our +x-ray generator + +with a copper target. + +Why do I tell you the +copper target? + +Because you're going to +fix the wavelength. + +And you fix the wavelength +by choosing the target. + +So we've got copper target in +our x-ray generator, OK? + +So remember, the sample +is not the target. + +The sample is what is +being irradiated. + +This is being bombed by the +electrons in the tube, copper + +target in x-ray tube, and that +means that the lambda of the + +radiation is lambda copper. + +And I'm going to use lambda +copper K alpha because I know + +it's wavelength to five +significant figures. + +It's 1.5418 angstroms. + +And here's the data set. + +I looked this up in +the literature. + +Here's the data set from +the experiment. + +And that's all you get, +a set of 2 thetas. + +So here's my challenge to you. + +I'm telling you you've got an +unknown sample that's cubic, + +and there's your data set. + +The task for you is determine +two parts to the question. + +And we're going to +do it together. + +First part, determine the +crystal structure. + +So it's either FCC, BCC, +or simple cubic. + +And the second part is +determine the lattice + +constant, the value of +the lattice constant. + +So you can get quantitative +measurements. + +So I'm going to show +you how to do it. + +So how are we going to do it? + +We're going to use +this technique. + +This is my self-help +book for you. + +And here's the key. + +Here's how I came +up with this. + +There's a way to unravel this. + +And the way you unravel this +is to take these two + +relationships. + +You have lambda equals +2d sin theta is 1. + +And you also know that d-- + +in fact, I'm going to keep +writing hkl subscripts here-- + +you know the dhkl +is equal to a. + +That's this lattice constant. + +Be sure this is lattice +constant. + +This is the cube edge +measurement lattice constant + +divided by the square root +of h squared plus k + +squared plus l squared. + +So what I do is I +combine the two. + +If you combine these two, +you can end up with this + +relationship. + +If you combine the two, you +get lambda squared over 4a + +squared equals sin squared theta +over h squared plus k + +squared plus l squared. + +And this is the key. + +Why is it the key? + +The value of lambda +is set by you. + +You chose the target. + +The value of a is set +by the sample. + +That's the lattice constant. + +So the ratio of two constants +is a constant. + +Agreed? + +So this is a constant. + +So if the left side of the +equation is a constant, the + +right side of the equation +must be a constant. + +But h, k, and l vary. + +And theta varies. + +But the ratio of the variation, +when mapped into + +sin square theta over h squared +plus k squared plus l + +squared, this must +be a constant. + +And that's going to be the +way I work through + +this delightful problem. + +So let's see. + +Start with 2 theta values, and +generate a set of sin squared + +theta values. + +That's what Sadoway says first. +So I took 2 theta. + +And all I did was make 1 theta, +and then took the sin + +of it, and then took +the square the sin. + +So this is the data set +transmogrified into sin + +squared theta. + +All right, what's the +next thing he says? + +Normalize by dividing through +with the first value. + +So I'm just going to take +this whole series and + +divide it by 0.143. + +And now I end up, instead +of 0.143, 0.191. + +I have 1, 1.34, and so on. + +That's what I mean +by normalize. + +Normalize to the first entry. + +OK, What's next thing he says? + +Clear fractions. + +Clear fractions from the +normalized column. + +So I'm going to multiply this +by a common number. + +Because 1.34, remember this +is experimental data. + +It's noisy. + +1.34 looks like 4/3. + +Doesn't it? + +It's fuzzy logic. + +And 2.67 looks like 2 +and 2/3, 3 and 2/3. + +That's roughly 4. + +5 and 1/3. + +The 3 looks like +a magic number. + +So if a multiply this column by +3, I get 3, 4, 8, 11, 12. + +What does it say next? + +Speculate on the h, k, l values, +that if expressed as h + +squared plus k squared plus l +squared would generate the + +sequence of the clear +fractions column. + +And then that's going to take +me to the selection rule. + +So I say, well how do I get 3? + +It's 1 plus 1 plus 1. + +4 is 2 squared plus 0 squared +plus zero squared. + +8 is 2 squared plus 2 squared +plus 0 squared. + +So I'm generating this thing. + +And now it's pretty +obvious, right? + +Because now I've got +to use these. + +And what do I see here? + +Well, 1 1 1 are all odd. + +2 0 0, all even. + +2 2 0, all even. + +Gee, this looks like it conforms +to the selection + +rules for Bragg reflection +from an FCC crystal + +And then to make sure that +I'm on to something, + +what I do is this. + +Compute for each theta the value +of sin square theta over + +h squared plus k squared plus +l squared on the basis of + +those assumed values. + +What I'm doing is I'm saying if +my hunch is right, whatever + +I choose for the theta and the +assumed value h squared plus k + +squared plus l squared, that +should be a constant that + +doesn't change. + +So let's test it. + +And sure enough, look. + +0.0477, 0.0478, so it looks +like I'm on to something. + +And furthermore, I know +what this is. + +That 0.0477 is this. + +This is 0.0477. + +And I know my lambda. + +That's 1.5418. + +So now I can calculate my a. + +So now I've determined +that it's FCC. + +Plus if I go ahead and I +calculate the a value, I get + +3.53 angstroms. And if it's FCC +and it's 3.53 angstroms, I + +bet it's nickel. + +So that's how you index +this stuff. + +So there we are. + +There are the selection rules. + +Now here's a little trick. + +Let me show you. + +Because when I go to index this, +the first thing I do is + +I go for low hanging fruit. + +If you start looking for whether +it's simple cubic, + +face-centered cubic, or +body-centered cubic, let's + +look at the sum. + +So I've got simple cubic, +body-centered cubic, and + +face-centered cubic. + +So the first plane on simple +cubic, it's going to give me + +everything. + +It's going to give me +1, 2, 3, 4, 5, 6. + +And FCC, what does it give us? + +If you start looking down +there, it gives you + +3, 4, 8, 11, 12. + +Well, this is so different. + +3, 4, 8, 11 is so different +from 1, 2, 3, 4. + +What does BCC give you? + +It gives you 2, 4, +6, 8, 10, 12. + +Can you see you have +a problem here? + +It's pretty easy to +pull out FCC. + +But look at these two. + +Since you don't know, you're +just normalizing. + +You can't tell. + +If I give you a number sequence +that is in the order + +2, 4, 6, 8, 10, how do you know +that that couldn't be 1, + +2, 3, 4, 5? + +There's a hook here, though. + +Look at the sequence of h +plus h squared plus k + +squared plus l squared. + +Do you notice that there's no +combination of h squared plus + +k squared plus l squared +that gives you 7? + +You get 6. + +And then the next one is 8. + +But there is a sequence +that gives you 14. + +So if you have a seventh line, +if the seventh line to the + +first line, the ratio of h +squared plus k squared plus l + +squared for angle number +7 to h squared plus k + +squared plus l squared. + +For angle number 1, if +it's equal to 7-- + +and point of fact it's +not 7:1, it's 14:2-- + +and if it's equal to 8 for +the seventh angle-- + +then it must be simple cubic. + +And now you've sorted +it all out. + +So you're an expert now. + +Now you can do it. + +OK, so you're going to get some +practice on homework. + +So you can index crystals. + +You can determine a +crystal structure. + +All right, a couple of other +things we can do. + +There is a second technique. + +And it's called Laue diffraction +after von Laue, + +who got the Nobel +Prize in 1914. + +He beat the Braggs by one +year for this technique. + +So he shines. + +In this case for Laue, it's a +slightly different technique. + +What Laue does, is he +uses light x-rays. + +That means variable lambda. + +So how would you get a fixed +value of lambda? + +Well, you would pick off one of +those lines, like maybe the + +K alpha line because it's +a nice, singular line. + +And repress the bremsstrahlung +and so on. + +But if I want a variable lambda, +where do I go for + +variable lambda? + +I repress the lines. + +And I go for the +bremsstrahlung. + +So now I've got lines varying +all across the x + +region of the spectrum. + +So I use variable lambda. + +And I fixed the angle of +incidence, whereas with + +diffractometry, I use a single +value of lambda and vary. + +So here's the cartoon which +shows what's going on. + +I'll do it one more time. + +So this is called +camera obscura, + +which is darkened room. + +That's all this means +is dark room. + +So let's say I've got the +specimen on the back wall of + +this thing, and what I've got +is white x-rays coming in. + +So the white x-ray enters +through the face. + +I've got the plate here, and +I've got the specimen sitting + +somewhere in between. + +And what happens is I +get a spot pattern. + +I get a spot pattern. + +And the spot pattern is +imitative of the symmetry of + +atomic arrangement. + +So I have to say a little bit +about symmetry so we know what + +that means. + +So let's take a look +at symmetry. + +So I'm going to talk a little +bit about rotational + +symmetries. + +So let's look at that. + +So first one I'm going to look +at is an 0 0 1 plane. + +So if I just take a projection +of an 0 0 1 plane, + +it looks like this. + +Doesn't it? + +It's just the cube edge, +or the cube bottom. + +So it's got a and +a as the edge. + +And now, the rotational +axis, it's about a + +normal rotational axis. + +A normal rotational axis. + +So what I'm going to ask is how +many degrees do I have to + +go through before I get +this same image back. + +You can see that you go 90 +degrees, it'll come back. + +If I stop at 45 degrees, it's +going to look like this. + +You're going to say I know +he moved the specimen. + +If I go 90 degrees, you +can't tell it apart. + +So we define fold. + +The fold is equal to +360 divided by the + +basic angle of rotation. + +So we would say that this plane +here exhibits 4-fold + +symmetry, OK? + +Let's do a second one. + +The second one is 0 1 1. + +So if I look at 0 1 1, +0 1 1 at this plane. + +0 1 1 goes across +the diagonal. + +So I'm going to take the +diagonal here and + +plot it like so. + +So it's going to have +an edge of a. + +And it's going to have the +diagonal, which is + +root 2 times a. + +And if I put a rotational axis +in the center of that, clearly + +if I go only 90 degrees, I'm +going to tell that the thing + +is rotated. + +I have to go 180 degrees before +I can't tell that + +there's been any disturbance. + +So this one here has +2-fold symmetry. + +We'll do one more. + +Because there's only three +major ones that we + +have to deal with. + +And that is going to +be the 1 1 1 plane. + +And the 1 1 1 plane. + +And the 1 1 1 plane, I think +I've got an image of it here. + +You can see the 1 1 1 plane +drawn in this cube. + +So what's the face of +1 1 1 look like? + +The face of 1 1 1 +looks like this. + +That's face of 1 1 1. + +And if you go through this +analysis, this is root 3a + +because it's a diagonal of +a difference persuasion. + +So this is 3-fold symmetry. + +This has 3-fold rotational +symmetry. + +And that means if I take +a crystal such + +as this, for example. + +I've told you before, this is +my silicon wafer, and this + +silicon wafer has been cut +from a single crystal. + +So I'm looking at the edge +of an atomic plane. + +The question is, which +one is it? + +The crystal didn't come with +a label on the side. + +I don't know what the crystal +growth axis was. + +I started with a single crystal, +and I dipped it into + +molten silicon. + +And just like rock mountain +candy, I drop the heating + +coils and cause the +liquid to solidify + +around the seed crystal. + +And I grow this salami that's +about 8 inches in diameter, + +about 2 meters long. + +So now I go and I cut these +things with the diamond wheel. + +So I'm cutting them normal to +the growth axis, but I still + +don't know what plane +I'm looking at. + +So if I use the Laue technique +and put the crystal like so, + +bombard it with white +x-rays, and I + +look at the spot pattern. + +The spot pattern is going +to give me one of those + +symmetries. + +And if I get a 3-fold +symmetry, I know I'm + +looking at 1 1 1. + +I mean, it's not going to +be some wacko plane. + +It's going to be either face, +edge, or diagonal. + +And on the basis of the symmetry +in the Laue pattern, + +I can tell which plane +I'm looking at. + +They use this stuff. + +They use it to make the devices +that are in your cell + +phone and your computer. + +I'm not just telling +you a story. + +All right. + +So let's look at some others. + +We'll go back to the +Escher prints. + +Everything has symmetry. + +OK, so what's this one? + +See this? + +What's the symmetry? + +4-fold. + +How about this one? + +What do you think? + +3-fold. + +I even went into Photoshop +just to show you + +how dedicated I am. + +So I took this image. + +And I told Photoshop to give +me 120 degrees rotation. + +And I got this. + +You can even see the fold +in the book there. + +So I'm really doing it. + +It's coming back. + +It's 120 degrees rotation. + +How about this one? + +That's 3. + +Now these are real +Laue patterns. + +This is 4-fold. + +This is obviously 3-fold. + +This one is hard to see. + +But it turns out it's 2-fold. + +The one axis is just +a little bit longer + +than the other axis. + +What about this one? + +That's our simple cubic puppy. + +Yes, 1-fold. + +Translational symmetry without +rotational symmetry. + +You can make this by just +moving them sideways. + +But you have to go all +the way around. + +So that's 1-fold symmetry +translation. + +Look at this one? + +What's going on here? + +Is that one of the +Bravais lattices? + +This is called Penrose tile, +again rotational symmetry + +without translational +symmetry. + +You can take a patch of this +and move it rotationally. + +But you can't take and +cover a wall with it. + +So that's rotational without +translational. + +See? + +You can go around this way. + +1, 2, 3, 4, 5, 6, 7, 8, 9, +10, and reproduce this. + +But you can't use this as a unit +cell and keep it hopping + +laterally and tile +a wall with it. + +Here's another one, not +a Bravais lattice. + +All right. + +So I told you at the beginning +of this unit that there are + +ordered solids and disordered +solids. + +We've been focusing +on ordered solids. + +They have a unit cell. + +They're periodic. + +And we call them crystals. + +And next week we're going +to start looking + +at disordered solid. + +So they have no building block, +no long range order. + +And we call them glasses. + +For a long time, people thought +that solis have to + +fall into one box or +the other box. + +And then the best thing +that can happen in + +science is not, oh, yeah. + +That's exactly what +I expected. + +It's, I wonder what +that means. + +And there was one of these +moments in 1982. + +In 1982, a man by the name of +Danny Shechtman from Technion + +in Israel, was over here in the +United States working at + +the National Institute of +Standards and Technology, + +which used to be National Bureau +of Standards down in + +Gaithersburg, Maryland. + +And he was looking at a set of +aluminum-manganese alloys. + +So aluminum is a metal. + +Manganese is a metal. + +You can make a solid solution +which we call an alloy. + +And these are highly ordered. + +And what he found in his Laue +measurements, were rotational + +symmetries that are impossible +in a crystal. + +He was getting 5-fold +symmetry. + +You can't get 5-fold symmetry. + +There is no set of planes +here that will give + +you a 5-fold symmetry. + +They lack translational +symmetry. + +They were called aperiodic. + +And the popular name for +them was quasicrystals. + +So here's the Laue pattern of +one of Danny Shechtman's + +aluminum-manganese specimens. + +I think this is 25% +manganese and + +aluminum if I'm not mistaken. + +So let's count, 1, 2, 3, +4, 5, 6, 7, 8, 9, 10. + +You can't have 10 or 5. + +Atoms don't work that way. + +But he got it. + +He got it, 5- fold, +72 degrees. + +Now this is really, +really exciting. + +This is a shot of +his lab book. + +You're looking over +his shoulder. + +These are the specimen +numbers. + +And this is aluminum 25% +manganese, April 8, 1982. + +So it's just another +day at work. + +You could be doing this. + +And he can't believe +what he's getting. + +He's wondering what's +going on. + +You can't contribute this to +a calibration error on the + +instrument. + +This thing is on unassailably +5-fold symmetry. + +The joke is that this is not +far from the Pentagon. + +Only within shouting distance +of the Pentagon would you + +discover 5-fold symmetry. + +So there it is. + +So where have we come +with all of this? + +We've come with the ability to +start with some very simple + +ideas about x-ray generation. + +And we've come to the point +where we can characterize + +crystals, get quantitative +measurements of their lattice + +constants, and by using Laue + +techniques, investigate symmetry. + +OK. + +Let's adjourn. + +We'll see you on Friday. \ No newline at end of file diff --git a/fQm97XdYErA.txt b/fQm97XdYErA.txt new file mode 100644 index 0000000000000000000000000000000000000000..bdb997c1da26f5a9e958527f626e0dbbe2702f76 --- /dev/null +++ b/fQm97XdYErA.txt @@ -0,0 +1,7955 @@ +align:start position:0% + +foreign + + align:start position:0% + + + + align:start position:0% + +welcome to another lecture in my series + + align:start position:0% +welcome to another lecture in my series + + + align:start position:0% +welcome to another lecture in my series +on Urban Energy Systems and policy my + + align:start position:0% +on Urban Energy Systems and policy my + + + align:start position:0% +on Urban Energy Systems and policy my +name is David Sue I'm a professor in the + + align:start position:0% +name is David Sue I'm a professor in the + + + align:start position:0% +name is David Sue I'm a professor in the +department of urban studies and planning + + align:start position:0% +department of urban studies and planning + + + align:start position:0% +department of urban studies and planning +MIT + + align:start position:0% +MIT + + + align:start position:0% +MIT +and today I want to talk about studies + + align:start position:0% +and today I want to talk about studies + + + align:start position:0% +and today I want to talk about studies +and future possible fuel use carbon + + align:start position:0% +and future possible fuel use carbon + + + align:start position:0% +and future possible fuel use carbon +capture utilization storage and nuclear + + align:start position:0% +capture utilization storage and nuclear + + + align:start position:0% +capture utilization storage and nuclear +power + + align:start position:0% +power + + + align:start position:0% +power +in short this is kind of a grab bag of + + align:start position:0% +in short this is kind of a grab bag of + + + align:start position:0% +in short this is kind of a grab bag of +topics thinking about how cities exist + + align:start position:0% +topics thinking about how cities exist + + + align:start position:0% +topics thinking about how cities exist +in the larger Energy System + + align:start position:0% +in the larger Energy System + + + align:start position:0% +in the larger Energy System +the readings for today are all in the + + align:start position:0% +the readings for today are all in the + + + align:start position:0% +the readings for today are all in the +syllabus you can also see them by + + align:start position:0% +syllabus you can also see them by + + + align:start position:0% +syllabus you can also see them by +clicking on the purple links in the PDF + + align:start position:0% +clicking on the purple links in the PDF + + + align:start position:0% +clicking on the purple links in the PDF +and again + + align:start position:0% +and again + + + align:start position:0% +and again +that kind of have a more + + align:start position:0% +that kind of have a more + + + align:start position:0% +that kind of have a more +um + + align:start position:0% +um + + + align:start position:0% +um +philosophical discussion are really + + align:start position:0% +philosophical discussion are really + + + align:start position:0% +philosophical discussion are really +about really about how cities exist + + align:start position:0% +about really about how cities exist + + + align:start position:0% +about really about how cities exist +within a much larger Energy System and + + align:start position:0% +within a much larger Energy System and + + + align:start position:0% +within a much larger Energy System and +the reason why we could talk about these + + align:start position:0% +the reason why we could talk about these + + + align:start position:0% +the reason why we could talk about these +scenarios for future energy use is that + + align:start position:0% +scenarios for future energy use is that + + + align:start position:0% +scenarios for future energy use is that +the context is going to decide what we + + align:start position:0% +the context is going to decide what we + + + align:start position:0% +the context is going to decide what we +provide to pursue in cities + + align:start position:0% +provide to pursue in cities + + + align:start position:0% +provide to pursue in cities +so just to kind of take a large picture + + align:start position:0% +so just to kind of take a large picture + + + align:start position:0% +so just to kind of take a large picture +view of what we're trying to do to + + align:start position:0% +view of what we're trying to do to + + + align:start position:0% +view of what we're trying to do to +decarbonation this is from 2019 the + + align:start position:0% +decarbonation this is from 2019 the + + + align:start position:0% +decarbonation this is from 2019 the +global carbon project and their headline + + align:start position:0% +global carbon project and their headline + + + align:start position:0% +global carbon project and their headline +in 2019 was that CO2 emissions grow a + + align:start position:0% +in 2019 was that CO2 emissions grow a + + + align:start position:0% +in 2019 was that CO2 emissions grow a +bit slowly emerging climate policies but + + align:start position:0% +bit slowly emerging climate policies but + + + align:start position:0% +bit slowly emerging climate policies but +it's important to note that even before + + align:start position:0% +it's important to note that even before + + + align:start position:0% +it's important to note that even before +covid fossil fossil fuel CO2 emissions + + align:start position:0% +covid fossil fossil fuel CO2 emissions + + + align:start position:0% +covid fossil fossil fuel CO2 emissions +were growing more slowly but did not yet + + align:start position:0% +were growing more slowly but did not yet + + + align:start position:0% +were growing more slowly but did not yet +Decline and of course as we know in this + + align:start position:0% +Decline and of course as we know in this + + + align:start position:0% +Decline and of course as we know in this +red circle reinforces deal with + + align:start position:0% +red circle reinforces deal with + + + align:start position:0% +red circle reinforces deal with +commissions have to decline to Net Zero + + align:start position:0% +commissions have to decline to Net Zero + + + align:start position:0% +commissions have to decline to Net Zero +by around mid-century to meet our Paris + + align:start position:0% +by around mid-century to meet our Paris + + + align:start position:0% +by around mid-century to meet our Paris +climate agreement goals which is to keep + + align:start position:0% +climate agreement goals which is to keep + + + align:start position:0% +climate agreement goals which is to keep +our global temperatures less than 1.5 + + align:start position:0% +our global temperatures less than 1.5 + + + align:start position:0% +our global temperatures less than 1.5 +degrees Celsius above + + align:start position:0% +degrees Celsius above + + + align:start position:0% +degrees Celsius above +um the previous averages which would + + align:start position:0% +um the previous averages which would + + + align:start position:0% +um the previous averages which would +avoid the most catastrophic effects of + + align:start position:0% +avoid the most catastrophic effects of + + + align:start position:0% +avoid the most catastrophic effects of +climate change and so this graph points + + align:start position:0% +climate change and so this graph points + + + align:start position:0% +climate change and so this graph points +out that in the last 10 years the growth + + align:start position:0% +out that in the last 10 years the growth + + + align:start position:0% +out that in the last 10 years the growth +of whole was slower relatively slower + + align:start position:0% +of whole was slower relatively slower + + + align:start position:0% +of whole was slower relatively slower +growth in the eight years up till covid + + align:start position:0% +growth in the eight years up till covid + + + align:start position:0% +growth in the eight years up till covid +in the 2019 projection was a slower + + align:start position:0% +in the 2019 projection was a slower + + + align:start position:0% +in the 2019 projection was a slower +decline still but not a slower growth + + align:start position:0% +decline still but not a slower growth + + + align:start position:0% +decline still but not a slower growth +still but did not yet decline + + align:start position:0% +still but did not yet decline + + + align:start position:0% +still but did not yet decline +if we look at the sources of global + + align:start position:0% +if we look at the sources of global + + + align:start position:0% +if we look at the sources of global +carbon emissions natural gas and oil are + + align:start position:0% +carbon emissions natural gas and oil are + + + align:start position:0% +carbon emissions natural gas and oil are +now the main drivers of global emissions + + align:start position:0% +now the main drivers of global emissions + + + align:start position:0% +now the main drivers of global emissions +growth you have gas growing about 2.6 + + align:start position:0% +growth you have gas growing about 2.6 + + + align:start position:0% +growth you have gas growing about 2.6 +percent per year oil growing 0.9 sorry + + align:start position:0% +percent per year oil growing 0.9 sorry + + + align:start position:0% +percent per year oil growing 0.9 sorry +in 2019 alone and coal actually + + align:start position:0% +in 2019 alone and coal actually + + + align:start position:0% +in 2019 alone and coal actually +declining in 2019 with lower projection + + align:start position:0% +declining in 2019 with lower projection + + + align:start position:0% +declining in 2019 with lower projection +uh land carbon emissions also slightly + + align:start position:0% +uh land carbon emissions also slightly + + + align:start position:0% +uh land carbon emissions also slightly +increased driving up emissions in 2019. + + align:start position:0% +increased driving up emissions in 2019. + + + align:start position:0% +increased driving up emissions in 2019. +now this brings us back to the + + align:start position:0% +now this brings us back to the + + + align:start position:0% +now this brings us back to the +decarbonization pathways we've talked + + align:start position:0% +decarbonization pathways we've talked + + + align:start position:0% +decarbonization pathways we've talked +about in one of the first lectures this + + align:start position:0% +about in one of the first lectures this + + + align:start position:0% +about in one of the first lectures this +is the reference case this is + + align:start position:0% +is the reference case this is + + + align:start position:0% +is the reference case this is +essentially how much energy the U.S + + align:start position:0% +essentially how much energy the U.S + + + align:start position:0% +essentially how much energy the U.S +economy currently uses in 2020 + + align:start position:0% +economy currently uses in 2020 + + + align:start position:0% +economy currently uses in 2020 +we've talked a lot about the scenario + + align:start position:0% +we've talked a lot about the scenario + + + align:start position:0% +we've talked a lot about the scenario +trying to achieve 100 renewable energy + + align:start position:0% +trying to achieve 100 renewable energy + + + align:start position:0% +trying to achieve 100 renewable energy +you can see that all the fossil fuel + + align:start position:0% +you can see that all the fossil fuel + + + align:start position:0% +you can see that all the fossil fuel +resources and resources have been + + align:start position:0% +resources and resources have been + + + align:start position:0% +resources and resources have been +replaced by renewable energy resources + + align:start position:0% +replaced by renewable energy resources + + + align:start position:0% +replaced by renewable energy resources +and of course of the third scenario + + align:start position:0% +and of course of the third scenario + + + align:start position:0% +and of course of the third scenario +which is the extentral low fuel price + + align:start position:0% +which is the extentral low fuel price + + + align:start position:0% +which is the extentral low fuel price +this is the central scenario where it's + + align:start position:0% +this is the central scenario where it's + + + align:start position:0% +this is the central scenario where it's +the lowest cost or least cost Pathway to + + align:start position:0% +the lowest cost or least cost Pathway to + + + align:start position:0% +the lowest cost or least cost Pathway to +decarbonization and this occurs in the + + align:start position:0% +decarbonization and this occurs in the + + + align:start position:0% +decarbonization and this occurs in the +scenario of a low fuel price meaning + + align:start position:0% +scenario of a low fuel price meaning + + + align:start position:0% +scenario of a low fuel price meaning +that fossil fuels remain relatively + + align:start position:0% +that fossil fuels remain relatively + + + align:start position:0% +that fossil fuels remain relatively +cheap so there are still some fossil + + align:start position:0% +cheap so there are still some fossil + + + align:start position:0% +cheap so there are still some fossil +fuel like natural gas and petroleum in + + align:start position:0% +fuel like natural gas and petroleum in + + + align:start position:0% +fuel like natural gas and petroleum in +this decarbonization pathway and we + + align:start position:0% +this decarbonization pathway and we + + + align:start position:0% +this decarbonization pathway and we +should know two things about the + + align:start position:0% +should know two things about the + + + align:start position:0% +should know two things about the +scenario + + align:start position:0% +scenario + + + align:start position:0% +scenario +first because it's the central at least + + align:start position:0% +first because it's the central at least + + + align:start position:0% +first because it's the central at least +cost pathway and its low fuel price + + align:start position:0% +cost pathway and its low fuel price + + + align:start position:0% +cost pathway and its low fuel price +scenario this is essentially a scenario + + align:start position:0% +scenario this is essentially a scenario + + + align:start position:0% +scenario this is essentially a scenario +they consider this paper if they have + + align:start position:0% +they consider this paper if they have + + + align:start position:0% +they consider this paper if they have +the maximum amount of fossil fuels that + + align:start position:0% +the maximum amount of fossil fuels that + + + align:start position:0% +the maximum amount of fossil fuels that +could be used you could still achieve + + align:start position:0% +could be used you could still achieve + + + align:start position:0% +could be used you could still achieve +decaronization and even in this scenario + + align:start position:0% +decaronization and even in this scenario + + + align:start position:0% +decaronization and even in this scenario +if we flip back a couple slides you can + + align:start position:0% +if we flip back a couple slides you can + + + align:start position:0% +if we flip back a couple slides you can +see that we currently have coal natural + + align:start position:0% +see that we currently have coal natural + + + align:start position:0% +see that we currently have coal natural +gaps petroleum around 31 exahjoules of + + align:start position:0% +gaps petroleum around 31 exahjoules of + + + align:start position:0% +gaps petroleum around 31 exahjoules of +natural gas and 39 exodules petroleum + + align:start position:0% +natural gas and 39 exodules petroleum + + + align:start position:0% +natural gas and 39 exodules petroleum +to go back to our Central low fuel price + + align:start position:0% +to go back to our Central low fuel price + + + align:start position:0% +to go back to our Central low fuel price +scenario you can see we only have about + + align:start position:0% +scenario you can see we only have about + + + align:start position:0% +scenario you can see we only have about +7.4 X volt of natural gas 512 exit + + align:start position:0% +7.4 X volt of natural gas 512 exit + + + align:start position:0% +7.4 X volt of natural gas 512 exit +joules of petroleum in both cases at + + align:start position:0% +joules of petroleum in both cases at + + + align:start position:0% +joules of petroleum in both cases at +about a 75 percent decline in how much + + align:start position:0% +about a 75 percent decline in how much + + + align:start position:0% +about a 75 percent decline in how much +energy we have to use from those two + + align:start position:0% +energy we have to use from those two + + + align:start position:0% +energy we have to use from those two +resources and still achieve + + align:start position:0% +resources and still achieve + + + align:start position:0% +resources and still achieve +decarbonization + + align:start position:0% +decarbonization + + + align:start position:0% +decarbonization +so the question is how do we go from + + align:start position:0% +so the question is how do we go from + + + align:start position:0% +so the question is how do we go from +reference case to a carbon neutral + + align:start position:0% +reference case to a carbon neutral + + + align:start position:0% +reference case to a carbon neutral +pathway that still has its fossil fuels + + align:start position:0% +pathway that still has its fossil fuels + + + align:start position:0% +pathway that still has its fossil fuels +we need to do four things this paper + + align:start position:0% +we need to do four things this paper + + + align:start position:0% +we need to do four things this paper +argues we have to lower our final energy + + align:start position:0% +argues we have to lower our final energy + + + align:start position:0% +argues we have to lower our final energy +use you can tell on the left hand side + + align:start position:0% +use you can tell on the left hand side + + + align:start position:0% +use you can tell on the left hand side +of all the same key diagrams there's + + align:start position:0% +of all the same key diagrams there's + + + align:start position:0% +of all the same key diagrams there's +less energy use going in in terms of + + align:start position:0% +less energy use going in in terms of + + + align:start position:0% +less energy use going in in terms of +primary energy + + align:start position:0% +primary energy + + + align:start position:0% +primary energy +decarbonize our electricity sources we + + align:start position:0% +decarbonize our electricity sources we + + + align:start position:0% +decarbonize our electricity sources we +can switch for follicle fuels good + + align:start position:0% +can switch for follicle fuels good + + + align:start position:0% +can switch for follicle fuels good +electricity in a lot of our energy + + align:start position:0% +electricity in a lot of our energy + + + align:start position:0% +electricity in a lot of our energy +technology or conversion Technologies + + align:start position:0% +technology or conversion Technologies + + + align:start position:0% +technology or conversion Technologies +and we need to do carbon capture + + align:start position:0% +and we need to do carbon capture + + + align:start position:0% +and we need to do carbon capture +utilization and storage that's what I + + align:start position:0% +utilization and storage that's what I + + + align:start position:0% +utilization and storage that's what I +want to talk about more now + + align:start position:0% +want to talk about more now + + + align:start position:0% +want to talk about more now +carbon capture utilization of storage + + align:start position:0% +carbon capture utilization of storage + + + align:start position:0% +carbon capture utilization of storage +why is this important + + align:start position:0% +why is this important + + + align:start position:0% +why is this important +well there's certain number of cons that + + align:start position:0% +well there's certain number of cons that + + + align:start position:0% +well there's certain number of cons that +people argue around ccufs one of the + + align:start position:0% +people argue around ccufs one of the + + + align:start position:0% +people argue around ccufs one of the +first cons is that it's been pushed by + + align:start position:0% +first cons is that it's been pushed by + + + align:start position:0% +first cons is that it's been pushed by +fossil fuel interest as a way to + + align:start position:0% +fossil fuel interest as a way to + + + align:start position:0% +fossil fuel interest as a way to +continue emissions if you look quite + + align:start position:0% +continue emissions if you look quite + + + align:start position:0% +continue emissions if you look quite +often on social media or quite often on + + align:start position:0% +often on social media or quite often on + + + align:start position:0% +often on social media or quite often on +the web if you have energy interests you + + align:start position:0% +the web if you have energy interests you + + + align:start position:0% +the web if you have energy interests you +may have been targeted by fossil fuel + + align:start position:0% +may have been targeted by fossil fuel + + + align:start position:0% +may have been targeted by fossil fuel +ads from Shell Exxon Chevron and other + + align:start position:0% +ads from Shell Exxon Chevron and other + + + align:start position:0% +ads from Shell Exxon Chevron and other +fossil fuel companies that argue that + + align:start position:0% +fossil fuel companies that argue that + + + align:start position:0% +fossil fuel companies that argue that +they're investing in carbon capture + + align:start position:0% +they're investing in carbon capture + + + align:start position:0% +they're investing in carbon capture +utilization and storage they're spending + + align:start position:0% +utilization and storage they're spending + + + align:start position:0% +utilization and storage they're spending +on these Technologies is a small + + align:start position:0% +on these Technologies is a small + + + align:start position:0% +on these Technologies is a small +fraction of what they're spending on + + align:start position:0% +fraction of what they're spending on + + + align:start position:0% +fraction of what they're spending on +their current extraction or new + + align:start position:0% +their current extraction or new + + + align:start position:0% +their current extraction or new +exploration operations to extract more + + align:start position:0% +exploration operations to extract more + + + align:start position:0% +exploration operations to extract more +fossil fuels so it's hard to argue that + + align:start position:0% +fossil fuels so it's hard to argue that + + + align:start position:0% +fossil fuels so it's hard to argue that +carbon capture utilization storage by + + align:start position:0% +carbon capture utilization storage by + + + align:start position:0% +carbon capture utilization storage by +fossil fuel companies May necessarily be + + align:start position:0% +fossil fuel companies May necessarily be + + + align:start position:0% +fossil fuel companies May necessarily be +in good faith + + align:start position:0% +in good faith + + + align:start position:0% +in good faith +another con with carbon Capital + + align:start position:0% +another con with carbon Capital + + + align:start position:0% +another con with carbon Capital +utilization storage or CC us support is + + align:start position:0% +utilization storage or CC us support is + + + align:start position:0% +utilization storage or CC us support is +that it's not economically competitive + + align:start position:0% +that it's not economically competitive + + + align:start position:0% +that it's not economically competitive +it's simply a higher cost of existing + + align:start position:0% +it's simply a higher cost of existing + + + align:start position:0% +it's simply a higher cost of existing +renewable alternatives + + align:start position:0% +renewable alternatives + + + align:start position:0% +renewable alternatives +another argument is that there's simply + + align:start position:0% +another argument is that there's simply + + + align:start position:0% +another argument is that there's simply +no fundamental economic value to scoring + + align:start position:0% +no fundamental economic value to scoring + + + align:start position:0% +no fundamental economic value to scoring +pardon except for avoiding the + + align:start position:0% +pardon except for avoiding the + + + align:start position:0% +pardon except for avoiding the +externalities of climate change in other + + align:start position:0% +externalities of climate change in other + + + align:start position:0% +externalities of climate change in other +words we should put Arvin we should + + align:start position:0% +words we should put Arvin we should + + + align:start position:0% +words we should put Arvin we should +store it if possible + + align:start position:0% +store it if possible + + + align:start position:0% +store it if possible +at the same time there's no fundamental + + align:start position:0% +at the same time there's no fundamental + + + align:start position:0% +at the same time there's no fundamental +use to get out of it unless we simply + + align:start position:0% +use to get out of it unless we simply + + + align:start position:0% +use to get out of it unless we simply +bit of a use to be avoiding the worst + + align:start position:0% +bit of a use to be avoiding the worst + + + align:start position:0% +bit of a use to be avoiding the worst +effects of climate change + + align:start position:0% +effects of climate change + + + align:start position:0% +effects of climate change +and because the only way that we could + + align:start position:0% +and because the only way that we could + + + align:start position:0% +and because the only way that we could +price actionality is through a carbon + + align:start position:0% +price actionality is through a carbon + + + align:start position:0% +price actionality is through a carbon +tax for Price these have not necessarily + + align:start position:0% +tax for Price these have not necessarily + + + align:start position:0% +tax for Price these have not necessarily +been proven to be politically viable in + + align:start position:0% +been proven to be politically viable in + + + align:start position:0% +been proven to be politically viable in +many cases so far you will notice that + + align:start position:0% +many cases so far you will notice that + + + align:start position:0% +many cases so far you will notice that +the new inflation reduction act does not + + align:start position:0% +the new inflation reduction act does not + + + align:start position:0% +the new inflation reduction act does not +include carbon products though there are + + align:start position:0% +include carbon products though there are + + + align:start position:0% +include carbon products though there are +still a number of politicians and policy + + align:start position:0% +still a number of politicians and policy + + + align:start position:0% +still a number of politicians and policy +makers who are still pushing for it + + align:start position:0% +makers who are still pushing for it + + + align:start position:0% +makers who are still pushing for it +of course one of the pros of carbon + + align:start position:0% +of course one of the pros of carbon + + + align:start position:0% +of course one of the pros of carbon +capture utilization storage is that in + + align:start position:0% +capture utilization storage is that in + + + align:start position:0% +capture utilization storage is that in +the short term we use still a lot of + + align:start position:0% +the short term we use still a lot of + + + align:start position:0% +the short term we use still a lot of +fossil fuels we also have relatively + + align:start position:0% +fossil fuels we also have relatively + + + align:start position:0% +fossil fuels we also have relatively +High possible fuel prices and so if we + + align:start position:0% +High possible fuel prices and so if we + + + align:start position:0% +High possible fuel prices and so if we +need to continue producing fossil fuels + + align:start position:0% +need to continue producing fossil fuels + + + align:start position:0% +need to continue producing fossil fuels +to avoid the worst short-term effects we + + align:start position:0% +to avoid the worst short-term effects we + + + align:start position:0% +to avoid the worst short-term effects we +are going to hopefully have carbon + + align:start position:0% +are going to hopefully have carbon + + + align:start position:0% +are going to hopefully have carbon +capture utilization storage to store or + + align:start position:0% +capture utilization storage to store or + + + align:start position:0% +capture utilization storage to store or +pronounce Gap emissions in the short + + align:start position:0% +pronounce Gap emissions in the short + + + align:start position:0% +pronounce Gap emissions in the short +term and in the future + + align:start position:0% +term and in the future + + + align:start position:0% +term and in the future +and one of the pros I guess for the idea + + align:start position:0% +and one of the pros I guess for the idea + + + align:start position:0% +and one of the pros I guess for the idea +of CC Us in the long term is that we + + align:start position:0% +of CC Us in the long term is that we + + + align:start position:0% +of CC Us in the long term is that we +simply need to reduce carbon + + align:start position:0% +simply need to reduce carbon + + + align:start position:0% +simply need to reduce carbon +concentration in the atmosphere the + + align:start position:0% +concentration in the atmosphere the + + + align:start position:0% +concentration in the atmosphere the +current levels are 415 parts per million + + align:start position:0% +current levels are 415 parts per million + + + align:start position:0% +current levels are 415 parts per million +if you simply stop reduce using + + align:start position:0% +if you simply stop reduce using + + + align:start position:0% +if you simply stop reduce using +pronounced apps or rather stop using + + align:start position:0% +pronounced apps or rather stop using + + + align:start position:0% +pronounced apps or rather stop using +volatile fuels tomorrow we'd still have + + align:start position:0% +volatile fuels tomorrow we'd still have + + + align:start position:0% +volatile fuels tomorrow we'd still have +to have a way to reduce our carbon + + align:start position:0% +to have a way to reduce our carbon + + + align:start position:0% +to have a way to reduce our carbon +concentration atmosphere to safe levels + + align:start position:0% +concentration atmosphere to safe levels + + + align:start position:0% +concentration atmosphere to safe levels +and so the latest ipct report + + align:start position:0% +and so the latest ipct report + + + align:start position:0% +and so the latest ipct report +recognizes that we need some kind of + + align:start position:0% +recognizes that we need some kind of + + + align:start position:0% +recognizes that we need some kind of +carbon dioxide removal or some kind of + + align:start position:0% +carbon dioxide removal or some kind of + + + align:start position:0% +carbon dioxide removal or some kind of +carbon capture utilization storage + + align:start position:0% +carbon capture utilization storage + + + align:start position:0% +carbon capture utilization storage +techniques to be developed + + align:start position:0% +techniques to be developed + + + align:start position:0% +techniques to be developed +and so this is actually uh to bring it + + align:start position:0% +and so this is actually uh to bring it + + + align:start position:0% +and so this is actually uh to bring it +back to what cities can or cannot do on + + align:start position:0% +back to what cities can or cannot do on + + + align:start position:0% +back to what cities can or cannot do on +one hand do you have the cities that are + + align:start position:0% +one hand do you have the cities that are + + + align:start position:0% +one hand do you have the cities that are +highlighted in blue Washington + + align:start position:0% +highlighted in blue Washington + + + align:start position:0% +highlighted in blue Washington +California and States like New York + + align:start position:0% +California and States like New York + + + align:start position:0% +California and States like New York +Vermont Massachusetts and + + align:start position:0% +Vermont Massachusetts and + + + align:start position:0% +Vermont Massachusetts and +um + + align:start position:0% +um + + + align:start position:0% +um +New York are all considering natural gas + + align:start position:0% +New York are all considering natural gas + + + align:start position:0% +New York are all considering natural gas +stems because simply we know that + + align:start position:0% +stems because simply we know that + + + align:start position:0% +stems because simply we know that +greenhouse gas emissions and car + + align:start position:0% +greenhouse gas emissions and car + + + align:start position:0% +greenhouse gas emissions and car +emissions and methane emissions + + align:start position:0% +emissions and methane emissions + + + align:start position:0% +emissions and methane emissions +especially are driving greenhouse gas + + align:start position:0% +especially are driving greenhouse gas + + + align:start position:0% +especially are driving greenhouse gas +Greenhouse climate change very quickly + + align:start position:0% +Greenhouse climate change very quickly + + + align:start position:0% +Greenhouse climate change very quickly +and so you have a number of cities and + + align:start position:0% +and so you have a number of cities and + + + align:start position:0% +and so you have a number of cities and +states all considering trying to pass + + align:start position:0% +states all considering trying to pass + + + align:start position:0% +states all considering trying to pass +the natural gas bans such as Berkeley + + align:start position:0% +the natural gas bans such as Berkeley + + + align:start position:0% +the natural gas bans such as Berkeley +California Seattle Washington I think + + align:start position:0% +California Seattle Washington I think + + + align:start position:0% +California Seattle Washington I think +San Jose also considered it and about 10 + + align:start position:0% +San Jose also considered it and about 10 + + + align:start position:0% +San Jose also considered it and about 10 +or 15 pounds in Massachusetts have also + + align:start position:0% +or 15 pounds in Massachusetts have also + + + align:start position:0% +or 15 pounds in Massachusetts have also +proposed it at the latest Massachusetts + + align:start position:0% +proposed it at the latest Massachusetts + + + align:start position:0% +proposed it at the latest Massachusetts +climate legislation allows 10 City to + + align:start position:0% +climate legislation allows 10 City to + + + align:start position:0% +climate legislation allows 10 City to +experimentally fish + + align:start position:0% +experimentally fish + + + align:start position:0% +experimentally fish +at the same time just to consider what + + align:start position:0% +at the same time just to consider what + + + align:start position:0% +at the same time just to consider what +cities can't do necessarily look at all + + align:start position:0% +cities can't do necessarily look at all + + + align:start position:0% +cities can't do necessarily look at all +the states here in red these are all + + align:start position:0% +the states here in red these are all + + + align:start position:0% +the states here in red these are all +states that have passed legislation that + + align:start position:0% +states that have passed legislation that + + + align:start position:0% +states that have passed legislation that +prohibit local governments from + + align:start position:0% +prohibit local governments from + + + align:start position:0% +prohibit local governments from +restricting natural gas utility service + + align:start position:0% +restricting natural gas utility service + + + align:start position:0% +restricting natural gas utility service +in other words the states are family + + align:start position:0% +in other words the states are family + + + align:start position:0% +in other words the states are family +what cities can do and so the reason why + + align:start position:0% +what cities can do and so the reason why + + + align:start position:0% +what cities can do and so the reason why +we're considering our Alternatives or + + align:start position:0% +we're considering our Alternatives or + + + align:start position:0% +we're considering our Alternatives or +with the possibility of how much fossil + + align:start position:0% +with the possibility of how much fossil + + + align:start position:0% +with the possibility of how much fossil +fuels we're going to use in the future + + align:start position:0% +fuels we're going to use in the future + + + align:start position:0% +fuels we're going to use in the future +it's because these two kinds of States + + align:start position:0% +it's because these two kinds of States + + + align:start position:0% +it's because these two kinds of States +frankly blue States and red states have + + align:start position:0% +frankly blue States and red states have + + + align:start position:0% +frankly blue States and red states have +fundamentally different views on what + + align:start position:0% +fundamentally different views on what + + + align:start position:0% +fundamentally different views on what +the future use of fossil fuels could be + + align:start position:0% +the future use of fossil fuels could be + + + align:start position:0% +the future use of fossil fuels could be +both consider how we might try to + + align:start position:0% +both consider how we might try to + + + align:start position:0% +both consider how we might try to +achieve decarbonization and whether + + align:start position:0% +achieve decarbonization and whether + + + align:start position:0% +achieve decarbonization and whether +navigants can consider to use fossil + + align:start position:0% +navigants can consider to use fossil + + + align:start position:0% +navigants can consider to use fossil +fuels whether we can continue to use + + align:start position:0% +fuels whether we can continue to use + + + align:start position:0% +fuels whether we can continue to use +fossil fuels this is going to drive what + + align:start position:0% +fossil fuels this is going to drive what + + + align:start position:0% +fossil fuels this is going to drive what +we do in cities in policy + + align:start position:0% + + + + align:start position:0% + +so there's a couple of different ways to + + align:start position:0% +so there's a couple of different ways to + + + align:start position:0% +so there's a couple of different ways to +do carbon capture and storage in the + + align:start position:0% +do carbon capture and storage in the + + + align:start position:0% +do carbon capture and storage in the +lithosphere or geosphere essentially + + align:start position:0% +lithosphere or geosphere essentially + + + align:start position:0% +lithosphere or geosphere essentially +into the Earth's mantle and this is a + + align:start position:0% +into the Earth's mantle and this is a + + + align:start position:0% +into the Earth's mantle and this is a +diagram for the wristman paper we read + + align:start position:0% +diagram for the wristman paper we read + + + align:start position:0% +diagram for the wristman paper we read +uh on Tuesday and this shows different + + align:start position:0% +uh on Tuesday and this shows different + + + align:start position:0% +uh on Tuesday and this shows different +ways of taking you can basically uh have + + align:start position:0% +ways of taking you can basically uh have + + + align:start position:0% +ways of taking you can basically uh have +a pipeline up to 500 kilometers that + + align:start position:0% +a pipeline up to 500 kilometers that + + + align:start position:0% +a pipeline up to 500 kilometers that +takes uh carbon dioxide or Advanced gas + + align:start position:0% +takes uh carbon dioxide or Advanced gas + + + align:start position:0% +takes uh carbon dioxide or Advanced gas +emissions from a power plant and brings + + align:start position:0% +emissions from a power plant and brings + + + align:start position:0% +emissions from a power plant and brings +it to a CCS storage facility so you have + + align:start position:0% +it to a CCS storage facility so you have + + + align:start position:0% +it to a CCS storage facility so you have +some flexibility in disaggregating where + + align:start position:0% +some flexibility in disaggregating where + + + align:start position:0% +some flexibility in disaggregating where +the power plant is and when the CCS + + align:start position:0% +the power plant is and when the CCS + + + align:start position:0% +the power plant is and when the CCS +storage facility is you can bring in + + align:start position:0% +storage facility is you can bring in + + + align:start position:0% +storage facility is you can bring in +this pipeline you might be able to bring + + align:start position:0% +this pipeline you might be able to bring + + + align:start position:0% +this pipeline you might be able to bring +it by ship you can inject CO2 and store + + align:start position:0% +it by ship you can inject CO2 and store + + + align:start position:0% +it by ship you can inject CO2 and store +on the ground and this shows all the + + align:start position:0% +on the ground and this shows all the + + + align:start position:0% +on the ground and this shows all the +different ways you can start in the + + align:start position:0% +different ways you can start in the + + + align:start position:0% +different ways you can start in the +ground you have this impermeable cap + + align:start position:0% +ground you have this impermeable cap + + + align:start position:0% +ground you have this impermeable cap +rock that keeps the CO2 underground you + + align:start position:0% +rock that keeps the CO2 underground you + + + align:start position:0% +rock that keeps the CO2 underground you +pump it to about 1.5 kilometers deep or + + align:start position:0% +pump it to about 1.5 kilometers deep or + + + align:start position:0% +pump it to about 1.5 kilometers deep or +more you can put the CO2 into a complete + + align:start position:0% +more you can put the CO2 into a complete + + + align:start position:0% +more you can put the CO2 into a complete +the oil or gas Reservoir you can put it + + align:start position:0% +the oil or gas Reservoir you can put it + + + align:start position:0% +the oil or gas Reservoir you can put it +into the natural saline aquifer and as + + align:start position:0% +into the natural saline aquifer and as + + + align:start position:0% +into the natural saline aquifer and as +this little inset shows this carbon + + align:start position:0% +this little inset shows this carbon + + + align:start position:0% +this little inset shows this carbon +dioxide becomes stabilized within the + + align:start position:0% +dioxide becomes stabilized within the + + + align:start position:0% +dioxide becomes stabilized within the +porous rock forms natural compound + + align:start position:0% +porous rock forms natural compound + + + align:start position:0% +porous rock forms natural compound +within the surprise surrounding Brine + + align:start position:0% +within the surprise surrounding Brine + + + align:start position:0% +within the surprise surrounding Brine +and minerals + + align:start position:0% +and minerals + + + align:start position:0% +and minerals +of course this brings us to other + + align:start position:0% +of course this brings us to other + + + align:start position:0% +of course this brings us to other +possible ways to do carbon Capital + + align:start position:0% +possible ways to do carbon Capital + + + align:start position:0% +possible ways to do carbon Capital +utilization storage you might remember + + align:start position:0% +utilization storage you might remember + + + align:start position:0% +utilization storage you might remember +this figure from the tumulty report we + + align:start position:0% +this figure from the tumulty report we + + + align:start position:0% +this figure from the tumulty report we +read maybe I think the second or third + + align:start position:0% +read maybe I think the second or third + + + align:start position:0% +read maybe I think the second or third +week of class this shows Ontario's Green + + align:start position:0% +week of class this shows Ontario's Green + + + align:start position:0% +week of class this shows Ontario's Green +Belt we discussed the implications of + + align:start position:0% +Belt we discussed the implications of + + + align:start position:0% +Belt we discussed the implications of +land use not only for urban growth but + + align:start position:0% +land use not only for urban growth but + + + align:start position:0% +land use not only for urban growth but +for possible carbon capture and Storage + + align:start position:0% +for possible carbon capture and Storage + + + align:start position:0% +for possible carbon capture and Storage +so about two summers ago I spent quite a + + align:start position:0% +so about two summers ago I spent quite a + + + align:start position:0% +so about two summers ago I spent quite a +bit of time talking to my MIT colleagues + + align:start position:0% +bit of time talking to my MIT colleagues + + + align:start position:0% +bit of time talking to my MIT colleagues +uh we worked on this planet Grand + + align:start position:0% +uh we worked on this planet Grand + + + align:start position:0% +uh we worked on this planet Grand +Challenge project and correct called + + align:start position:0% +Challenge project and correct called + + + align:start position:0% +Challenge project and correct called +carbon and we produced from it out of + + align:start position:0% +carbon and we produced from it out of + + + align:start position:0% +carbon and we produced from it out of +the series of Graphics showing different + + align:start position:0% +the series of Graphics showing different + + + align:start position:0% +the series of Graphics showing different +ways that you might be able to express + + align:start position:0% +ways that you might be able to express + + + align:start position:0% +ways that you might be able to express +your apartment into direct field uh or + + align:start position:0% +your apartment into direct field uh or + + + align:start position:0% +your apartment into direct field uh or +into the biosphere + + align:start position:0% +into the biosphere + + + align:start position:0% +into the biosphere +so and one possibility is that you take + + align:start position:0% +so and one possibility is that you take + + + align:start position:0% +so and one possibility is that you take +carbon and you sequester into the soil + + align:start position:0% +carbon and you sequester into the soil + + + align:start position:0% +carbon and you sequester into the soil +microbiome the major medical engineer as + + align:start position:0% +microbiome the major medical engineer as + + + align:start position:0% +microbiome the major medical engineer as +the soil microbiome to uptake more + + align:start position:0% +the soil microbiome to uptake more + + + align:start position:0% +the soil microbiome to uptake more +carbon + + align:start position:0% +carbon + + + align:start position:0% +carbon +another possibility is perennial crops + + align:start position:0% +another possibility is perennial crops + + + align:start position:0% +another possibility is perennial crops +parental crops unlike annual crops are + + align:start position:0% +parental crops unlike annual crops are + + + align:start position:0% +parental crops unlike annual crops are +agricultural crops that actually can be + + align:start position:0% +agricultural crops that actually can be + + + align:start position:0% +agricultural crops that actually can be +harvested every year if they don't + + align:start position:0% +harvested every year if they don't + + + align:start position:0% +harvested every year if they don't +require replanting their root systems + + align:start position:0% +require replanting their root systems + + + align:start position:0% +require replanting their root systems +typically grow much deeper than typical + + align:start position:0% +typically grow much deeper than typical + + + align:start position:0% +typically grow much deeper than typical +annual crops the things we currently + + align:start position:0% +annual crops the things we currently + + + align:start position:0% +annual crops the things we currently +plant in a harvest every year Cornell + + align:start position:0% +plant in a harvest every year Cornell + + + align:start position:0% +plant in a harvest every year Cornell +crops because the root systems go down + + align:start position:0% +crops because the root systems go down + + + align:start position:0% +crops because the root systems go down +much deeper and they store more carbon + + align:start position:0% +much deeper and they store more carbon + + + align:start position:0% +much deeper and they store more carbon +into the soil + + align:start position:0% +into the soil + + + align:start position:0% +into the soil +another possibility is for crypto carbon + + align:start position:0% +another possibility is for crypto carbon + + + align:start position:0% +another possibility is for crypto carbon +in agricultural soils is abandoned + + align:start position:0% +in agricultural soils is abandoned + + + align:start position:0% +in agricultural soils is abandoned +croplands if abandoned croplands are no + + align:start position:0% +croplands if abandoned croplands are no + + + align:start position:0% +croplands if abandoned croplands are no +longer need to be harvested then we + + align:start position:0% +longer need to be harvested then we + + + align:start position:0% +longer need to be harvested then we +could store carbon into the soil and + + align:start position:0% +could store carbon into the soil and + + + align:start position:0% +could store carbon into the soil and +Abandoned cropland and leave it there + + align:start position:0% +Abandoned cropland and leave it there + + + align:start position:0% +Abandoned cropland and leave it there +these are all possibilities for + + align:start position:0% +these are all possibilities for + + + align:start position:0% +these are all possibilities for +agricultural soils + + align:start position:0% +agricultural soils + + + align:start position:0% +agricultural soils +another possibility for carbon capture + + align:start position:0% +another possibility for carbon capture + + + align:start position:0% +another possibility for carbon capture +its utilization of storage is forward + + align:start position:0% +its utilization of storage is forward + + + align:start position:0% +its utilization of storage is forward +sequestration + + align:start position:0% +sequestration + + + align:start position:0% +sequestration +in many cases you have natural carbon + + align:start position:0% +in many cases you have natural carbon + + + align:start position:0% +in many cases you have natural carbon +dioxide emissions from say a volcano you + + align:start position:0% +dioxide emissions from say a volcano you + + + align:start position:0% +dioxide emissions from say a volcano you +get Forest fertilization this is a + + align:start position:0% +get Forest fertilization this is a + + + align:start position:0% +get Forest fertilization this is a +ecosystem cycle that happens to my + + align:start position:0% +ecosystem cycle that happens to my + + + align:start position:0% +ecosystem cycle that happens to my +colleagues study you can see the CO2 is + + align:start position:0% +colleagues study you can see the CO2 is + + + align:start position:0% +colleagues study you can see the CO2 is +being prepared into a forest another + + align:start position:0% +being prepared into a forest another + + + align:start position:0% +being prepared into a forest another +possibility is terabetta this is + + align:start position:0% +possibility is terabetta this is + + + align:start position:0% +possibility is terabetta this is +something that Tyler Parham has studied + + align:start position:0% +something that Tyler Parham has studied + + + align:start position:0% +something that Tyler Parham has studied +in heaps uh how actually ancient + + align:start position:0% +in heaps uh how actually ancient + + + align:start position:0% +in heaps uh how actually ancient +cultures actually use charcoal and waste + + align:start position:0% +cultures actually use charcoal and waste + + + align:start position:0% +cultures actually use charcoal and waste +processes to actually create fairly rich + + align:start position:0% +processes to actually create fairly rich + + + align:start position:0% +processes to actually create fairly rich +soil called the Amazon apparently it + + align:start position:0% +soil called the Amazon apparently it + + + align:start position:0% +soil called the Amazon apparently it +results resulting in much more fertile + + align:start position:0% +results resulting in much more fertile + + + align:start position:0% +results resulting in much more fertile +soil for the Amazon lab today and one + + align:start position:0% +soil for the Amazon lab today and one + + + align:start position:0% +soil for the Amazon lab today and one +simple way to sequester carbon into soil + + align:start position:0% +simple way to sequester carbon into soil + + + align:start position:0% +simple way to sequester carbon into soil +is to avoid illegal logging and + + align:start position:0% +is to avoid illegal logging and + + + align:start position:0% +is to avoid illegal logging and +deforestation we know that quite a bit + + align:start position:0% +deforestation we know that quite a bit + + + align:start position:0% +deforestation we know that quite a bit +of carbon is sequestered in the Amazon + + align:start position:0% +of carbon is sequestered in the Amazon + + + align:start position:0% +of carbon is sequestered in the Amazon +rainforest we want to avoid illegal + + align:start position:0% +rainforest we want to avoid illegal + + + align:start position:0% +rainforest we want to avoid illegal +logging and deforestation in places like + + align:start position:0% +logging and deforestation in places like + + + align:start position:0% +logging and deforestation in places like +the Amazon if it's like Indonesia we can + + align:start position:0% +the Amazon if it's like Indonesia we can + + + align:start position:0% +the Amazon if it's like Indonesia we can +avoid that legal logging deforestation + + align:start position:0% +avoid that legal logging deforestation + + + align:start position:0% +avoid that legal logging deforestation +where essentially saving carbon dioxide + + align:start position:0% +where essentially saving carbon dioxide + + + align:start position:0% +where essentially saving carbon dioxide +from being released to the atmosphere + + align:start position:0% +from being released to the atmosphere + + + align:start position:0% +from being released to the atmosphere +another possibility of for storing + + align:start position:0% +another possibility of for storing + + + align:start position:0% +another possibility of for storing +carbon is in the hydrosphere this is + + align:start position:0% +carbon is in the hydrosphere this is + + + align:start position:0% +carbon is in the hydrosphere this is +something that hiding net and others + + align:start position:0% +something that hiding net and others + + + align:start position:0% +something that hiding net and others +have studied uh Charles Harvey in civil + + align:start position:0% +have studied uh Charles Harvey in civil + + + align:start position:0% +have studied uh Charles Harvey in civil +engineering studies how much carbon the + + align:start position:0% +engineering studies how much carbon the + + + align:start position:0% +engineering studies how much carbon the +sequester currently impede lands + + align:start position:0% +sequester currently impede lands + + + align:start position:0% +sequester currently impede lands +peatlands are essentially a decaying of + + align:start position:0% +peatlands are essentially a decaying of + + + align:start position:0% +peatlands are essentially a decaying of +vegetation from many centuries before + + align:start position:0% +vegetation from many centuries before + + + align:start position:0% +vegetation from many centuries before +they actually sequester quite a bit of + + align:start position:0% +they actually sequester quite a bit of + + + align:start position:0% +they actually sequester quite a bit of +carbon permafrost currently stores a lot + + align:start position:0% +carbon permafrost currently stores a lot + + + align:start position:0% +carbon permafrost currently stores a lot +of carbon in places like Siberia this is + + align:start position:0% +of carbon in places like Siberia this is + + + align:start position:0% +of carbon in places like Siberia this is +something we want to avoid warming the + + align:start position:0% +something we want to avoid warming the + + + align:start position:0% +something we want to avoid warming the +Earth because if we do have warming no + + align:start position:0% +Earth because if we do have warming no + + + align:start position:0% +Earth because if we do have warming no +release carbon dioxide and methane into + + align:start position:0% +release carbon dioxide and methane into + + + align:start position:0% +release carbon dioxide and methane into +the atmosphere + + align:start position:0% +the atmosphere + + + align:start position:0% +the atmosphere +Heidi NEP and others in MIT have studied + + align:start position:0% +Heidi NEP and others in MIT have studied + + + align:start position:0% +Heidi NEP and others in MIT have studied +uh postal hydrosphere or Postal + + align:start position:0% +uh postal hydrosphere or Postal + + + align:start position:0% +uh postal hydrosphere or Postal +sequestration of carbon I think blue um + + align:start position:0% +sequestration of carbon I think blue um + + + align:start position:0% +sequestration of carbon I think blue um +blue carbon is what they call it where + + align:start position:0% +blue carbon is what they call it where + + + align:start position:0% +blue carbon is what they call it where +you star store carbon dioxide in + + align:start position:0% +you star store carbon dioxide in + + + align:start position:0% +you star store carbon dioxide in +mangroves and salt marshes and + + align:start position:0% +mangroves and salt marshes and + + + align:start position:0% +mangroves and salt marshes and +seagrasses + + align:start position:0% +seagrasses + + + align:start position:0% +seagrasses +so these are all possibilities for + + align:start position:0% +so these are all possibilities for + + + align:start position:0% +so these are all possibilities for +carbon after utilization storage + + align:start position:0% +carbon after utilization storage + + + align:start position:0% +carbon after utilization storage +uh if we think about the utilization + + align:start position:0% +uh if we think about the utilization + + + align:start position:0% +uh if we think about the utilization +part of it what we might use carbon for + + align:start position:0% +part of it what we might use carbon for + + + align:start position:0% +part of it what we might use carbon for +this is and again I show you a McKinsey + + align:start position:0% +this is and again I show you a McKinsey + + + align:start position:0% +this is and again I show you a McKinsey +graph because this is the marginal + + align:start position:0% +graph because this is the marginal + + + align:start position:0% +graph because this is the marginal +Bateman plus curve that we've been + + align:start position:0% +Bateman plus curve that we've been + + + align:start position:0% +Bateman plus curve that we've been +talking about in previous classes on the + + align:start position:0% +talking about in previous classes on the + + + align:start position:0% +talking about in previous classes on the +vertical axis is the willingness to pay + + align:start position:0% +vertical axis is the willingness to pay + + + align:start position:0% +vertical axis is the willingness to pay +for manufacturers for CO2 in other words + + align:start position:0% +for manufacturers for CO2 in other words + + + align:start position:0% +for manufacturers for CO2 in other words +lots of Manufacturers have to need CO2 + + align:start position:0% +lots of Manufacturers have to need CO2 + + + align:start position:0% +lots of Manufacturers have to need CO2 +as feedstock it's on the positive side + + align:start position:0% +as feedstock it's on the positive side + + + align:start position:0% +as feedstock it's on the positive side +manufacturers are willing to pay for + + align:start position:0% +manufacturers are willing to pay for + + + align:start position:0% +manufacturers are willing to pay for +carbon dioxide on the negative side + + align:start position:0% +carbon dioxide on the negative side + + + align:start position:0% +carbon dioxide on the negative side +they're willing to pay to get rid of CO2 + + align:start position:0% +they're willing to pay to get rid of CO2 + + + align:start position:0% +they're willing to pay to get rid of CO2 +or they'd actually have to spend more + + align:start position:0% +or they'd actually have to spend more + + + align:start position:0% +or they'd actually have to spend more +money to take up CO2 so if you look at + + align:start position:0% +money to take up CO2 so if you look at + + + align:start position:0% +money to take up CO2 so if you look at +it right now there's this blue bar this + + align:start position:0% +it right now there's this blue bar this + + + align:start position:0% +it right now there's this blue bar this +is the expected cost for direct capture + + align:start position:0% +is the expected cost for direct capture + + + align:start position:0% +is the expected cost for direct capture +by 2030 and this is a typical cost of + + align:start position:0% +by 2030 and this is a typical cost of + + + align:start position:0% +by 2030 and this is a typical cost of +CO2 capture for high security Point + + align:start position:0% +CO2 capture for high security Point + + + align:start position:0% +CO2 capture for high security Point +sources so right now we can typically + + align:start position:0% +sources so right now we can typically + + + align:start position:0% +sources so right now we can typically +capture CO2 for high Purity Point + + align:start position:0% +capture CO2 for high Purity Point + + + align:start position:0% +capture CO2 for high Purity Point +sources and the economic uses of that + + align:start position:0% +sources and the economic uses of that + + + align:start position:0% +sources and the economic uses of that +are in things like biochar or carbon + + align:start position:0% +are in things like biochar or carbon + + + align:start position:0% +are in things like biochar or carbon +making compartment fiber in greenhouses + + align:start position:0% +making compartment fiber in greenhouses + + + align:start position:0% +making compartment fiber in greenhouses +and food and beverages right now we + + align:start position:0% +and food and beverages right now we + + + align:start position:0% +and food and beverages right now we +can't capture CO2 at economically viable + + align:start position:0% +can't capture CO2 at economically viable + + + align:start position:0% +can't capture CO2 at economically viable +price to use in applications like cement + + align:start position:0% +price to use in applications like cement + + + align:start position:0% +price to use in applications like cement +cement can actually made Stronger by + + align:start position:0% +cement can actually made Stronger by + + + align:start position:0% +cement can actually made Stronger by +adding carbon dioxide to it you can use + + align:start position:0% +adding carbon dioxide to it you can use + + + align:start position:0% +adding carbon dioxide to it you can use +it to do enhanced oil recovery you can + + align:start position:0% +it to do enhanced oil recovery you can + + + align:start position:0% +it to do enhanced oil recovery you can +actually pump CO2 into an oil reservoir + + align:start position:0% +actually pump CO2 into an oil reservoir + + + align:start position:0% +actually pump CO2 into an oil reservoir +and drive out more oil that way but + + align:start position:0% +and drive out more oil that way but + + + align:start position:0% +and drive out more oil that way but +right now it's not necessarily cost + + align:start position:0% +right now it's not necessarily cost + + + align:start position:0% +right now it's not necessarily cost +effective in many cases Aggregates + + align:start position:0% +effective in many cases Aggregates + + + align:start position:0% +effective in many cases Aggregates +storage these are all things that aren't + + align:start position:0% +storage these are all things that aren't + + + align:start position:0% +storage these are all things that aren't +necessarily possible to use with high + + align:start position:0% +necessarily possible to use with high + + + align:start position:0% +necessarily possible to use with high +Purity Point sources right now McKenzie + + align:start position:0% +Purity Point sources right now McKenzie + + + align:start position:0% +Purity Point sources right now McKenzie +report was interesting and then they + + align:start position:0% +report was interesting and then they + + + align:start position:0% +report was interesting and then they +look at what the viable Marketplace is + + align:start position:0% +look at what the viable Marketplace is + + + align:start position:0% +look at what the viable Marketplace is +for cc us now + + align:start position:0% +for cc us now + + + align:start position:0% +for cc us now +and they also do this I think useful + + align:start position:0% +and they also do this I think useful + + + align:start position:0% +and they also do this I think useful +graphic just showing potential + + align:start position:0% +graphic just showing potential + + + align:start position:0% +graphic just showing potential +industrial sources for carbon capture + + align:start position:0% +industrial sources for carbon capture + + + align:start position:0% +industrial sources for carbon capture +use in storage there's many plentiful uh + + align:start position:0% +use in storage there's many plentiful uh + + + align:start position:0% +use in storage there's many plentiful uh +sources you can see they have the sector + + align:start position:0% +sources you can see they have the sector + + + align:start position:0% +sources you can see they have the sector +here our heavy Industries High Purity + + align:start position:0% +here our heavy Industries High Purity + + + align:start position:0% +here our heavy Industries High Purity +industrial Point sources and diffuse and + + align:start position:0% +industrial Point sources and diffuse and + + + align:start position:0% +industrial Point sources and diffuse and +mobile emissions and they have a number + + align:start position:0% +mobile emissions and they have a number + + + align:start position:0% +mobile emissions and they have a number +of sites here so we actually have + + align:start position:0% +of sites here so we actually have + + + align:start position:0% +of sites here so we actually have +1400 sites for power those are + + align:start position:0% +1400 sites for power those are + + + align:start position:0% +1400 sites for power those are +essentially power plants average + + align:start position:0% +essentially power plants average + + + align:start position:0% +essentially power plants average +emissions per site in terms of the mega + + align:start position:0% +emissions per site in terms of the mega + + + align:start position:0% +emissions per site in terms of the mega +tons of CO2 are 1.3 it's very hard to + + align:start position:0% +tons of CO2 are 1.3 it's very hard to + + + align:start position:0% +tons of CO2 are 1.3 it's very hard to +capture a CO2 from heavy industry and + + align:start position:0% +capture a CO2 from heavy industry and + + + align:start position:0% +capture a CO2 from heavy industry and +from high Purity in-depthal Point + + align:start position:0% +from high Purity in-depthal Point + + + align:start position:0% +from high Purity in-depthal Point +sources because their emissions per site + + align:start position:0% +sources because their emissions per site + + + align:start position:0% +sources because their emissions per site +is quite low so you have to build all + + align:start position:0% +is quite low so you have to build all + + + align:start position:0% +is quite low so you have to build all +the same infrastructure or it may not be + + align:start position:0% +the same infrastructure or it may not be + + + align:start position:0% +the same infrastructure or it may not be +worth building infrastructure just to + + align:start position:0% +worth building infrastructure just to + + + align:start position:0% +worth building infrastructure just to +capture the low vision per site of + + align:start position:0% +capture the low vision per site of + + + align:start position:0% +capture the low vision per site of +course it's very hard to capture CO2 + + align:start position:0% +course it's very hard to capture CO2 + + + align:start position:0% +course it's very hard to capture CO2 +from diffuse or mobile emissions + + align:start position:0% +from diffuse or mobile emissions + + + align:start position:0% +from diffuse or mobile emissions +if we look at the work of David Keith a + + align:start position:0% +if we look at the work of David Keith a + + + align:start position:0% +if we look at the work of David Keith a +professor both of biophysics and policy + + align:start position:0% +professor both of biophysics and policy + + + align:start position:0% +professor both of biophysics and policy +at Harvard he has a firm with many + + align:start position:0% +at Harvard he has a firm with many + + + align:start position:0% +at Harvard he has a firm with many +people working for department of + + align:start position:0% +people working for department of + + + align:start position:0% +people working for department of +engineering and this is what the subject + + align:start position:0% +engineering and this is what the subject + + + align:start position:0% +engineering and this is what the subject +of the David Roberts article was which + + align:start position:0% +of the David Roberts article was which + + + align:start position:0% +of the David Roberts article was which +is what the viable uses of direct air + + align:start position:0% +is what the viable uses of direct air + + + align:start position:0% +is what the viable uses of direct air +capture might be as he points out in + + align:start position:0% +capture might be as he points out in + + + align:start position:0% +capture might be as he points out in +this article it may not necessarily + + align:start position:0% +this article it may not necessarily + + + align:start position:0% +this article it may not necessarily +solve climate change it's not a silver + + align:start position:0% +solve climate change it's not a silver + + + align:start position:0% +solve climate change it's not a silver +bullet but there are interesting use + + align:start position:0% +bullet but there are interesting use + + + align:start position:0% +bullet but there are interesting use +cases that are actually promising + + align:start position:0% +cases that are actually promising + + + align:start position:0% +cases that are actually promising +developments + + align:start position:0% +developments + + + align:start position:0% +developments +so one particular case now this is just + + align:start position:0% +so one particular case now this is just + + + align:start position:0% +so one particular case now this is just +my carbon engineering website you can + + align:start position:0% +my carbon engineering website you can + + + align:start position:0% +my carbon engineering website you can +see that they have the solution called + + align:start position:0% +see that they have the solution called + + + align:start position:0% +see that they have the solution called +air to Fuels and that their carbon + + align:start position:0% +air to Fuels and that their carbon + + + align:start position:0% +air to Fuels and that their carbon +Engineering Process and direct air + + align:start position:0% +Engineering Process and direct air + + + align:start position:0% +Engineering Process and direct air +capture is a way of delivering synthetic + + align:start position:0% +capture is a way of delivering synthetic + + + align:start position:0% +capture is a way of delivering synthetic +Ultra load private fuels such as + + align:start position:0% +Ultra load private fuels such as + + + align:start position:0% +Ultra load private fuels such as +gasoline Diesel and Jet Jet fuels out of + + align:start position:0% +gasoline Diesel and Jet Jet fuels out of + + + align:start position:0% +gasoline Diesel and Jet Jet fuels out of +air I'm sorry jet a grade fuel uh fuel + + align:start position:0% +air I'm sorry jet a grade fuel uh fuel + + + align:start position:0% +air I'm sorry jet a grade fuel uh fuel +out of air water and renewable + + align:start position:0% +out of air water and renewable + + + align:start position:0% +out of air water and renewable +electricity this is the air to fuel + + align:start position:0% +electricity this is the air to fuel + + + align:start position:0% +electricity this is the air to fuel +solution that Roberts talks about in his + + align:start position:0% +solution that Roberts talks about in his + + + align:start position:0% +solution that Roberts talks about in his +article + + align:start position:0% +article + + + align:start position:0% +article +uh if you look at how this works we have + + align:start position:0% +uh if you look at how this works we have + + + align:start position:0% +uh if you look at how this works we have +CO2 in the atmosphere we capture it + + align:start position:0% +CO2 in the atmosphere we capture it + + + align:start position:0% +CO2 in the atmosphere we capture it +through direct air capture we take the + + align:start position:0% +through direct air capture we take the + + + align:start position:0% +through direct air capture we take the +atmospheric CO2 put into a fuel + + align:start position:0% +atmospheric CO2 put into a fuel + + + align:start position:0% +atmospheric CO2 put into a fuel +synthesis and we put in electricity a + + align:start position:0% +synthesis and we put in electricity a + + + align:start position:0% +synthesis and we put in electricity a +renewable electricity and water and we + + align:start position:0% +renewable electricity and water and we + + + align:start position:0% +renewable electricity and water and we +get Ultra load carbon fuels out of it so + + align:start position:0% +get Ultra load carbon fuels out of it so + + + align:start position:0% +get Ultra load carbon fuels out of it so +this is if this is not necessarily a + + align:start position:0% +this is if this is not necessarily a + + + align:start position:0% +this is if this is not necessarily a +carbon negative process it is at least + + align:start position:0% +carbon negative process it is at least + + + align:start position:0% +carbon negative process it is at least +at best a compartment neutral process or + + align:start position:0% +at best a compartment neutral process or + + + align:start position:0% +at best a compartment neutral process or +a way of providing ultra low carbon + + align:start position:0% +a way of providing ultra low carbon + + + align:start position:0% +a way of providing ultra low carbon +fuels and as the Roberts article points + + align:start position:0% +fuels and as the Roberts article points + + + align:start position:0% +fuels and as the Roberts article points +out there are states or there are policy + + align:start position:0% +out there are states or there are policy + + + align:start position:0% +out there are states or there are policy +situations like California's ultra low + + align:start position:0% +situations like California's ultra low + + + align:start position:0% +situations like California's ultra low +fuel standard where this may make this + + align:start position:0% +fuel standard where this may make this + + + align:start position:0% +fuel standard where this may make this +economically viable to produce this hard + + align:start position:0% +economically viable to produce this hard + + + align:start position:0% +economically viable to produce this hard +fuel in this way and it may make + + align:start position:0% +fuel in this way and it may make + + + align:start position:0% +fuel in this way and it may make +economically viable for one large actor + + align:start position:0% +economically viable for one large actor + + + align:start position:0% +economically viable for one large actor +to sign a power purchase agreement to + + align:start position:0% +to sign a power purchase agreement to + + + align:start position:0% +to sign a power purchase agreement to +buy a set amount of ultra low carbon + + align:start position:0% +buy a set amount of ultra low carbon + + + align:start position:0% +buy a set amount of ultra low carbon +fuels + + align:start position:0% +fuels + + + align:start position:0% +fuels +are there possibilities for the direct + + align:start position:0% +are there possibilities for the direct + + + align:start position:0% +are there possibilities for the direct +aircraft to technology that carbon + + align:start position:0% +aircraft to technology that carbon + + + align:start position:0% +aircraft to technology that carbon +engineering is developing is sucking + + align:start position:0% +engineering is developing is sucking + + + align:start position:0% +engineering is developing is sucking +carbonate out of the atmosphere directly + + align:start position:0% +carbonate out of the atmosphere directly + + + align:start position:0% +carbonate out of the atmosphere directly +to correct air factor I think it's + + align:start position:0% +to correct air factor I think it's + + + align:start position:0% +to correct air factor I think it's +permanent geological storage instead of + + align:start position:0% +permanent geological storage instead of + + + align:start position:0% +permanent geological storage instead of +the pipeline I showed you in the + + align:start position:0% +the pipeline I showed you in the + + + align:start position:0% +the pipeline I showed you in the +previous diagram it would just be the + + align:start position:0% +previous diagram it would just be the + + + align:start position:0% +previous diagram it would just be the +direct air capture technology instead of + + align:start position:0% +direct air capture technology instead of + + + align:start position:0% +direct air capture technology instead of +apparently piloting I think in British + + align:start position:0% +apparently piloting I think in British + + + align:start position:0% +apparently piloting I think in British +Columbia + + align:start position:0% +Columbia + + + align:start position:0% +Columbia +another possibility is what I mentioned + + align:start position:0% +another possibility is what I mentioned + + + align:start position:0% +another possibility is what I mentioned +before enhanced oil recovery you take + + align:start position:0% +before enhanced oil recovery you take + + + align:start position:0% +before enhanced oil recovery you take +atmospheric CO2 capture from direct air + + align:start position:0% +atmospheric CO2 capture from direct air + + + align:start position:0% +atmospheric CO2 capture from direct air +capture you can permanently store this + + align:start position:0% +capture you can permanently store this + + + align:start position:0% +capture you can permanently store this +in oil reservoir of the current oil + + align:start position:0% +in oil reservoir of the current oil + + + align:start position:0% +in oil reservoir of the current oil +production this is one situation that + + align:start position:0% +production this is one situation that + + + align:start position:0% +production this is one situation that +I've always been a little skeptical of + + align:start position:0% +I've always been a little skeptical of + + + align:start position:0% +I've always been a little skeptical of +that you know you can basically drive so + + align:start position:0% +that you know you can basically drive so + + + align:start position:0% +that you know you can basically drive so +much CO2 into the oil reservoir you can + + align:start position:0% +much CO2 into the oil reservoir you can + + + align:start position:0% +much CO2 into the oil reservoir you can +pump out the oil and somehow that still + + align:start position:0% +pump out the oil and somehow that still + + + align:start position:0% +pump out the oil and somehow that still +result in a low carbon fuel standard but + + align:start position:0% +result in a low carbon fuel standard but + + + align:start position:0% +result in a low carbon fuel standard but +you know if it had sold out if the + + align:start position:0% +you know if it had sold out if the + + + align:start position:0% +you know if it had sold out if the +calculations work out there's been more + + align:start position:0% +calculations work out there's been more + + + align:start position:0% +calculations work out there's been more +than one or two startups trying to do + + align:start position:0% +than one or two startups trying to do + + + align:start position:0% +than one or two startups trying to do +enhanced oil recovery using CO2 or + + align:start position:0% +enhanced oil recovery using CO2 or + + + align:start position:0% +enhanced oil recovery using CO2 or +trying to show that it could be a carbon + + align:start position:0% +trying to show that it could be a carbon + + + align:start position:0% +trying to show that it could be a carbon +neutral or carbon negative process + + align:start position:0% +neutral or carbon negative process + + + align:start position:0% +neutral or carbon negative process +and so we just destroy the diagram for + + align:start position:0% +and so we just destroy the diagram for + + + align:start position:0% +and so we just destroy the diagram for +the cover engineering website in this + + align:start position:0% +the cover engineering website in this + + + align:start position:0% +the cover engineering website in this +situation we have CO2 in the atmosphere + + align:start position:0% +situation we have CO2 in the atmosphere + + + align:start position:0% +situation we have CO2 in the atmosphere +we capture the director capture we + + align:start position:0% +we capture the director capture we + + + align:start position:0% +we capture the director capture we +inject it into a oil reservoir we + + align:start position:0% +inject it into a oil reservoir we + + + align:start position:0% +inject it into a oil reservoir we +actually get more crude oil out we + + align:start position:0% +actually get more crude oil out we + + + align:start position:0% +actually get more crude oil out we +refine it and we get fossil fuels put it + + align:start position:0% +refine it and we get fossil fuels put it + + + align:start position:0% +refine it and we get fossil fuels put it +into our existing infrastructure this is + + align:start position:0% +into our existing infrastructure this is + + + align:start position:0% +into our existing infrastructure this is +also meant to try to meet from the ultra + + align:start position:0% +also meant to try to meet from the ultra + + + align:start position:0% +also meant to try to meet from the ultra +low carbon fuel standards + + align:start position:0% +low carbon fuel standards + + + align:start position:0% +low carbon fuel standards +this brings me to Sprite to negative + + align:start position:0% +this brings me to Sprite to negative + + + align:start position:0% +this brings me to Sprite to negative +emissions commitment this is a project + + align:start position:0% +emissions commitment this is a project + + + align:start position:0% +emissions commitment this is a project +I've been following for a couple years + + align:start position:0% +I've been following for a couple years + + + align:start position:0% +I've been following for a couple years +and many people have been following + + align:start position:0% +and many people have been following + + + align:start position:0% +and many people have been following +stripe as you may know is an online + + align:start position:0% +stripe as you may know is an online + + + align:start position:0% +stripe as you may know is an online +payments company but in 2020 or 2019 I + + align:start position:0% +payments company but in 2020 or 2019 I + + + align:start position:0% +payments company but in 2020 or 2019 I +think they announced their negative + + align:start position:0% +think they announced their negative + + + align:start position:0% +think they announced their negative +admissions commitment which is when they + + align:start position:0% +admissions commitment which is when they + + + align:start position:0% +admissions commitment which is when they +pledge to pay one million dollars per + + align:start position:0% +pledge to pay one million dollars per + + + align:start position:0% +pledge to pay one million dollars per +year at any price the direct removal of + + align:start position:0% +year at any price the direct removal of + + + align:start position:0% +year at any price the direct removal of +carbon dioxide in the atmosphere and + + align:start position:0% +carbon dioxide in the atmosphere and + + + align:start position:0% +carbon dioxide in the atmosphere and +sequestration and long-term storage they + + align:start position:0% +sequestration and long-term storage they + + + align:start position:0% +sequestration and long-term storage they +built up a small team to evaluate + + align:start position:0% +built up a small team to evaluate + + + align:start position:0% +built up a small team to evaluate +different carbon removal Technologies + + align:start position:0% +different carbon removal Technologies + + + align:start position:0% +different carbon removal Technologies +and in 2020 they announced their first + + align:start position:0% +and in 2020 they announced their first + + + align:start position:0% +and in 2020 they announced their first +carbon removal purchases this was + + align:start position:0% +carbon removal purchases this was + + + align:start position:0% +carbon removal purchases this was +essentially a commitment the company + + align:start position:0% +essentially a commitment the company + + + align:start position:0% +essentially a commitment the company +made to try to pay money to start to + + align:start position:0% +made to try to pay money to start to + + + align:start position:0% +made to try to pay money to start to +Foster or start to build the market for + + align:start position:0% +Foster or start to build the market for + + + align:start position:0% +Foster or start to build the market for +negative emissions or perform removal + + align:start position:0% +negative emissions or perform removal + + + align:start position:0% +negative emissions or perform removal +and so I think this is a project I've + + align:start position:0% +and so I think this is a project I've + + + align:start position:0% +and so I think this is a project I've +been very interested in because they're + + align:start position:0% +been very interested in because they're + + + align:start position:0% +been very interested in because they're +very transparent on the criteria are and + + align:start position:0% +very transparent on the criteria are and + + + align:start position:0% +very transparent on the criteria are and +they're very transparent about the + + align:start position:0% +they're very transparent about the + + + align:start position:0% +they're very transparent about the +technology they're trying to Foster and + + align:start position:0% +technology they're trying to Foster and + + + align:start position:0% +technology they're trying to Foster and +if you look at their website you can + + align:start position:0% +if you look at their website you can + + + align:start position:0% +if you look at their website you can +click on the purple link up here to see + + align:start position:0% +click on the purple link up here to see + + + align:start position:0% +click on the purple link up here to see +their website you will see that they + + align:start position:0% +their website you will see that they + + + align:start position:0% +their website you will see that they +actually have almost all of these + + align:start position:0% +actually have almost all of these + + + align:start position:0% +actually have almost all of these +submissions and they show exactly how + + align:start position:0% +submissions and they show exactly how + + + align:start position:0% +submissions and they show exactly how +they evaluated submissions and why + + align:start position:0% +they evaluated submissions and why + + + align:start position:0% +they evaluated submissions and why +they've picked a certain portfolio + + align:start position:0% +they've picked a certain portfolio + + + align:start position:0% +they've picked a certain portfolio +Technologies + + align:start position:0% +Technologies + + + align:start position:0% +Technologies +so uh their criteria I think are very + + align:start position:0% +so uh their criteria I think are very + + + align:start position:0% +so uh their criteria I think are very +clear they show what their criteria are + + align:start position:0% +clear they show what their criteria are + + + align:start position:0% +clear they show what their criteria are +whether or not it's possible today the + + align:start position:0% +whether or not it's possible today the + + + align:start position:0% +whether or not it's possible today the +target is by 2040. so they're very clear + + align:start position:0% +target is by 2040. so they're very clear + + + align:start position:0% +target is by 2040. so they're very clear +that vrx making these purchases could + + align:start position:0% +that vrx making these purchases could + + + align:start position:0% +that vrx making these purchases could +try to Foster these Technologies so the + + align:start position:0% +try to Foster these Technologies so the + + + align:start position:0% +try to Foster these Technologies so the +criteria are they want everything to be + + align:start position:0% +criteria are they want everything to be + + + align:start position:0% +criteria are they want everything to be +sequestered beyond the biosphere this + + align:start position:0% +sequestered beyond the biosphere this + + + align:start position:0% +sequestered beyond the biosphere this +fundamentally shows a very different + + align:start position:0% +fundamentally shows a very different + + + align:start position:0% +fundamentally shows a very different +approach than the peripheral uh carbon + + align:start position:0% +approach than the peripheral uh carbon + + + align:start position:0% +approach than the peripheral uh carbon +product brand challenge team from MIT + + align:start position:0% +product brand challenge team from MIT + + + align:start position:0% +product brand challenge team from MIT +and that stripe doesn't actually believe + + align:start position:0% +and that stripe doesn't actually believe + + + align:start position:0% +and that stripe doesn't actually believe +that sequestering uh uh carbon in the + + align:start position:0% +that sequestering uh uh carbon in the + + + align:start position:0% +that sequestering uh uh carbon in the +biosphere is going to be effective this + + align:start position:0% +biosphere is going to be effective this + + + align:start position:0% +biosphere is going to be effective this +is because if you store things in the + + align:start position:0% +is because if you store things in the + + + align:start position:0% +is because if you store things in the +biosphere it may actually lead to you + + align:start position:0% +biosphere it may actually lead to you + + + align:start position:0% +biosphere it may actually lead to you +might have wildfires in the future and + + align:start position:0% +might have wildfires in the future and + + + align:start position:0% +might have wildfires in the future and +now I simply get rid of or obvious the + + align:start position:0% +now I simply get rid of or obvious the + + + align:start position:0% +now I simply get rid of or obvious the +effects of these carbon capture as sort + + align:start position:0% +effects of these carbon capture as sort + + + align:start position:0% +effects of these carbon capture as sort +of signature they also typically add + + align:start position:0% +of signature they also typically add + + + align:start position:0% +of signature they also typically add +very Silicon Valley Way evaluate whether + + align:start position:0% +very Silicon Valley Way evaluate whether + + + align:start position:0% +very Silicon Valley Way evaluate whether +or not this technology has a path to be + + align:start position:0% +or not this technology has a path to be + + + align:start position:0% +or not this technology has a path to be +a meaningful part of the carbon removal + + align:start position:0% +a meaningful part of the carbon removal + + + align:start position:0% +a meaningful part of the carbon removal +solution portfolio where that you can + + align:start position:0% +solution portfolio where that you can + + + align:start position:0% +solution portfolio where that you can +achieve sufficient volume + + align:start position:0% +achieve sufficient volume + + + align:start position:0% +achieve sufficient volume +it has to have a path to achieving uh + + align:start position:0% +it has to have a path to achieving uh + + + align:start position:0% +it has to have a path to achieving uh +being affordable at scale it has to + + align:start position:0% +being affordable at scale it has to + + + align:start position:0% +being affordable at scale it has to +achieve permanent storage of carbon + + align:start position:0% +achieve permanent storage of carbon + + + align:start position:0% +achieve permanent storage of carbon +currently we can store for greater than + + align:start position:0% +currently we can store for greater than + + + align:start position:0% +currently we can store for greater than +a thousand years as they that's their + + align:start position:0% +a thousand years as they that's their + + + align:start position:0% +a thousand years as they that's their +Target in 2040 their target or cost is + + align:start position:0% +Target in 2040 their target or cost is + + + align:start position:0% +Target in 2040 their target or cost is +less than a hundred dollars on their + + align:start position:0% +less than a hundred dollars on their + + + align:start position:0% +less than a hundred dollars on their +volume has to be a minimum of 0.5 bigot + + align:start position:0% +volume has to be a minimum of 0.5 bigot + + + align:start position:0% +volume has to be a minimum of 0.5 bigot +tons per year + + align:start position:0% +tons per year + + + align:start position:0% +tons per year +and the criteria are that the carbon + + align:start position:0% +and the criteria are that the carbon + + + align:start position:0% +and the criteria are that the carbon +sequestration have to be scientifically + + align:start position:0% +sequestration have to be scientifically + + + align:start position:0% +sequestration have to be scientifically +rigorous and transparent for + + align:start position:0% +rigorous and transparent for + + + align:start position:0% +rigorous and transparent for +verifiability + + align:start position:0% +verifiability + + + align:start position:0% +verifiability +it has to meet standards for quality and + + align:start position:0% +it has to meet standards for quality and + + + align:start position:0% +it has to meet standards for quality and +safety and be globally responsible and + + align:start position:0% +safety and be globally responsible and + + + align:start position:0% +safety and be globally responsible and +it has to have a net negative life cycle + + align:start position:0% +it has to have a net negative life cycle + + + align:start position:0% +it has to have a net negative life cycle +So currently we have a negativity ratio + + align:start position:0% +So currently we have a negativity ratio + + + align:start position:0% +So currently we have a negativity ratio +like this is reducing net atmospheric + + align:start position:0% +like this is reducing net atmospheric + + + align:start position:0% +like this is reducing net atmospheric +CO2 + + align:start position:0% +CO2 + + + align:start position:0% +CO2 +expresses a ratio subject to appropriate + + align:start position:0% +expresses a ratio subject to appropriate + + + align:start position:0% +expresses a ratio subject to appropriate +boundary conditions this is currently a + + align:start position:0% +boundary conditions this is currently a + + + align:start position:0% +boundary conditions this is currently a +negativity ratio of less than or equal + + align:start position:0% +negativity ratio of less than or equal + + + align:start position:0% +negativity ratio of less than or equal +to one and of course in the future they + + align:start position:0% +to one and of course in the future they + + + align:start position:0% +to one and of course in the future they +want negativity ratio of less than one + + align:start position:0% +want negativity ratio of less than one + + + align:start position:0% +want negativity ratio of less than one +they want to get a net negative life + + align:start position:0% +they want to get a net negative life + + + align:start position:0% +they want to get a net negative life +cycle or the showing that we have net + + align:start position:0% +cycle or the showing that we have net + + + align:start position:0% +cycle or the showing that we have net +atmospheric carbon removed so this is + + align:start position:0% +atmospheric carbon removed so this is + + + align:start position:0% +atmospheric carbon removed so this is +what you know stripe is paying for in + + align:start position:0% +what you know stripe is paying for in + + + align:start position:0% +what you know stripe is paying for in +the first year they picked four + + align:start position:0% +the first year they picked four + + + align:start position:0% +the first year they picked four +Technologies I think ranging about 16 + + align:start position:0% +Technologies I think ranging about 16 + + + align:start position:0% +Technologies I think ranging about 16 +per kind about six hundred dollars per + + align:start position:0% +per kind about six hundred dollars per + + + align:start position:0% +per kind about six hundred dollars per +ton simply because they had a portfolio + + align:start position:0% +ton simply because they had a portfolio + + + align:start position:0% +ton simply because they had a portfolio +they're trying to venture capital way + + align:start position:0% +they're trying to venture capital way + + + align:start position:0% +they're trying to venture capital way +they're into new technologies to for + + align:start position:0% +they're into new technologies to for + + + align:start position:0% +they're into new technologies to for +negative emissions + + align:start position:0% +negative emissions + + + align:start position:0% +negative emissions +and I I just to encourage you all to + + align:start position:0% +and I I just to encourage you all to + + + align:start position:0% +and I I just to encourage you all to +consider this to make context of your + + align:start position:0% +consider this to make context of your + + + align:start position:0% +consider this to make context of your +future careers they say it's a call to + + align:start position:0% +future careers they say it's a call to + + + align:start position:0% +future careers they say it's a call to +action the goal is not only to remove + + align:start position:0% +action the goal is not only to remove + + + align:start position:0% +action the goal is not only to remove +carbon from the atmosphere but to create + + align:start position:0% +carbon from the atmosphere but to create + + + align:start position:0% +carbon from the atmosphere but to create +a ecosystem of funders and Founders that + + align:start position:0% +a ecosystem of funders and Founders that + + + align:start position:0% +a ecosystem of funders and Founders that +will invent ways to solve the world's + + align:start position:0% +will invent ways to solve the world's + + + align:start position:0% +will invent ways to solve the world's +largest action problem or continue to + + align:start position:0% +largest action problem or continue to + + + align:start position:0% +largest action problem or continue to +search for Creative projects and experts + + align:start position:0% +search for Creative projects and experts + + + align:start position:0% +search for Creative projects and experts +reach out to us to work together on this + + align:start position:0% +reach out to us to work together on this + + + align:start position:0% +reach out to us to work together on this +effort or give any feedback and if + + align:start position:0% +effort or give any feedback and if + + + align:start position:0% +effort or give any feedback and if +you're an engineer or designer who cares + + align:start position:0% +you're an engineer or designer who cares + + + align:start position:0% +you're an engineer or designer who cares +about climate impact consider joining + + align:start position:0% +about climate impact consider joining + + + align:start position:0% +about climate impact consider joining +their team + + align:start position:0% +their team + + + align:start position:0% +their team +this has in the last two years Advanced + + align:start position:0% +this has in the last two years Advanced + + + align:start position:0% +this has in the last two years Advanced +even further you see this new uh + + align:start position:0% +even further you see this new uh + + + align:start position:0% +even further you see this new uh +commitment pulse Frontier led by stripe + + align:start position:0% +commitment pulse Frontier led by stripe + + + align:start position:0% +commitment pulse Frontier led by stripe +but joined by alphabet Shopify meta and + + align:start position:0% +but joined by alphabet Shopify meta and + + + align:start position:0% +but joined by alphabet Shopify meta and +McKinsey company these are not small + + align:start position:0% +McKinsey company these are not small + + + align:start position:0% +McKinsey company these are not small +companies this is essentially taking + + align:start position:0% +companies this is essentially taking + + + align:start position:0% +companies this is essentially taking +Stripes negative emissions commitment + + align:start position:0% +Stripes negative emissions commitment + + + align:start position:0% +Stripes negative emissions commitment +and expanding it even further what they + + align:start position:0% +and expanding it even further what they + + + align:start position:0% +and expanding it even further what they +call what they have said this basically + + align:start position:0% +call what they have said this basically + + + align:start position:0% +call what they have said this basically +a negative emissions commitment is is + + align:start position:0% +a negative emissions commitment is is + + + align:start position:0% +a negative emissions commitment is is +called an advanced Market commitment to + + align:start position:0% +called an advanced Market commitment to + + + align:start position:0% +called an advanced Market commitment to +accelerate carbon removal it's an + + align:start position:0% +accelerate carbon removal it's an + + + align:start position:0% +accelerate carbon removal it's an +advanced Market commitment because + + align:start position:0% +advanced Market commitment because + + + align:start position:0% +advanced Market commitment because +you're making the market by pledging + + align:start position:0% +you're making the market by pledging + + + align:start position:0% +you're making the market by pledging +money going forward by pledging the + + align:start position:0% +money going forward by pledging the + + + align:start position:0% +money going forward by pledging the +money is what's going to get people to + + align:start position:0% +money is what's going to get people to + + + align:start position:0% +money is what's going to get people to +enter the market with a long-term + + align:start position:0% +enter the market with a long-term + + + align:start position:0% +enter the market with a long-term +commitment to develop new technologies + + align:start position:0% +commitment to develop new technologies + + + align:start position:0% +commitment to develop new technologies +so scaling up from scribe's original one + + align:start position:0% +so scaling up from scribe's original one + + + align:start position:0% +so scaling up from scribe's original one +million dollar purchase in 2020 Frontier + + align:start position:0% +million dollar purchase in 2020 Frontier + + + align:start position:0% +million dollar purchase in 2020 Frontier +is an alliance to pay all this company + + align:start position:0% +is an alliance to pay all this company + + + align:start position:0% +is an alliance to pay all this company +is led by stripe which is Advanced + + align:start position:0% +is led by stripe which is Advanced + + + align:start position:0% +is led by stripe which is Advanced +Market committed to buy initial 925 + + align:start position:0% +Market committed to buy initial 925 + + + align:start position:0% +Market committed to buy initial 925 +million dollars of primary carpet + + align:start position:0% +million dollars of primary carpet + + + align:start position:0% +million dollars of primary carpet +removal between 2022 and 2030. tens of + + align:start position:0% +removal between 2022 and 2030. tens of + + + align:start position:0% +removal between 2022 and 2030. tens of +thousands of businesses have joined + + align:start position:0% +thousands of businesses have joined + + + align:start position:0% +thousands of businesses have joined +stripe because stripe re quickly + + align:start position:0% +stripe because stripe re quickly + + + align:start position:0% +stripe because stripe re quickly +realized they're building a platform for + + align:start position:0% +realized they're building a platform for + + + align:start position:0% +realized they're building a platform for +negative emissions commitment and other + + align:start position:0% +negative emissions commitment and other + + + align:start position:0% +negative emissions commitment and other +companies wanted an easy way to try to + + align:start position:0% +companies wanted an easy way to try to + + + align:start position:0% +companies wanted an easy way to try to +do negative missions in a way that was + + align:start position:0% +do negative missions in a way that was + + + align:start position:0% +do negative missions in a way that was +verifiable perhaps more verifiable than + + align:start position:0% +verifiable perhaps more verifiable than + + + align:start position:0% +verifiable perhaps more verifiable than +a lot of our discussion around offsets + + align:start position:0% +a lot of our discussion around offsets + + + align:start position:0% +a lot of our discussion around offsets +so this brings us to another uh + + align:start position:0% +so this brings us to another uh + + + align:start position:0% +so this brings us to another uh +alternative feature for energy is this + + align:start position:0% +alternative feature for energy is this + + + align:start position:0% +alternative feature for energy is this +kind of question of nuclear and there's + + align:start position:0% +kind of question of nuclear and there's + + + align:start position:0% +kind of question of nuclear and there's +this uh I think silly question and I + + align:start position:0% +this uh I think silly question and I + + + align:start position:0% +this uh I think silly question and I +think + + align:start position:0% +think + + + align:start position:0% +think +um it was discussed recently in a + + align:start position:0% +um it was discussed recently in a + + + align:start position:0% +um it was discussed recently in a +podcast by David Roberts and others + + align:start position:0% +podcast by David Roberts and others + + + align:start position:0% +podcast by David Roberts and others +which is are you Pro or anti-nuclear is + + align:start position:0% +which is are you Pro or anti-nuclear is + + + align:start position:0% +which is are you Pro or anti-nuclear is +essentially a silly question you can + + align:start position:0% +essentially a silly question you can + + + align:start position:0% +essentially a silly question you can +make Pro or anti-arguments and we'll + + align:start position:0% +make Pro or anti-arguments and we'll + + + align:start position:0% +make Pro or anti-arguments and we'll +talk about those uh but there's maybe + + align:start position:0% +talk about those uh but there's maybe + + + align:start position:0% +talk about those uh but there's maybe +other ways we should think about it on + + align:start position:0% +other ways we should think about it on + + + align:start position:0% +other ways we should think about it on +the pro side the support team the point + + align:start position:0% +the pro side the support team the point + + + align:start position:0% +the pro side the support team the point +at all 2018 paper that I assigned for + + align:start position:0% +at all 2018 paper that I assigned for + + + align:start position:0% +at all 2018 paper that I assigned for +today makes convincing argument that + + align:start position:0% +today makes convincing argument that + + + align:start position:0% +today makes convincing argument that +it'll be more expensive to achieve + + align:start position:0% +it'll be more expensive to achieve + + + align:start position:0% +it'll be more expensive to achieve +decarbonization without firm resources + + align:start position:0% +decarbonization without firm resources + + + align:start position:0% +decarbonization without firm resources +and just to add another uh reason why + + align:start position:0% +and just to add another uh reason why + + + align:start position:0% +and just to add another uh reason why +they don't they don't consider this + + align:start position:0% +they don't they don't consider this + + + align:start position:0% +they don't they don't consider this +paper land use we know that solar and + + align:start position:0% +paper land use we know that solar and + + + align:start position:0% +paper land use we know that solar and +wind are less energy dense we'll talk + + align:start position:0% +wind are less energy dense we'll talk + + + align:start position:0% +wind are less energy dense we'll talk +about that next week and we know land + + align:start position:0% +about that next week and we know land + + + align:start position:0% +about that next week and we know land +use and permitting may be a serious + + align:start position:0% +use and permitting may be a serious + + + align:start position:0% +use and permitting may be a serious +problem for Renewables having said that + + align:start position:0% +problem for Renewables having said that + + + align:start position:0% +problem for Renewables having said that +land use may also be a problem for new + + align:start position:0% +land use may also be a problem for new + + + align:start position:0% +land use may also be a problem for new +nuclear power plants + + align:start position:0% +nuclear power plants + + + align:start position:0% +nuclear power plants +but on arguments against nuclear are + + align:start position:0% +but on arguments against nuclear are + + + align:start position:0% +but on arguments against nuclear are +will nuclear power ever get cheaper and + + align:start position:0% +will nuclear power ever get cheaper and + + + align:start position:0% +will nuclear power ever get cheaper and +we'll go into that argument in a little + + align:start position:0% +we'll go into that argument in a little + + + align:start position:0% +we'll go into that argument in a little +bit and of course there's other reasons + + align:start position:0% +bit and of course there's other reasons + + + align:start position:0% +bit and of course there's other reasons +why we might not want to use nuclear + + align:start position:0% +why we might not want to use nuclear + + + align:start position:0% +why we might not want to use nuclear +power nuclear waste proliferation of + + align:start position:0% +power nuclear waste proliferation of + + + align:start position:0% +power nuclear waste proliferation of +nuclear technology our concerns or have + + align:start position:0% +nuclear technology our concerns or have + + + align:start position:0% +nuclear technology our concerns or have +always been concerned writing the + + align:start position:0% +always been concerned writing the + + + align:start position:0% +always been concerned writing the +technology + + align:start position:0% +technology + + + align:start position:0% +technology +the reason why I guess + + align:start position:0% +the reason why I guess + + + align:start position:0% +the reason why I guess +um + + align:start position:0% +um + + + align:start position:0% +um +we can argue that this Pro or + + align:start position:0% +we can argue that this Pro or + + + align:start position:0% +we can argue that this Pro or +anti-nuclear stance may be silly it's + + align:start position:0% +anti-nuclear stance may be silly it's + + + align:start position:0% +anti-nuclear stance may be silly it's +because there's a more useful way to + + align:start position:0% +because there's a more useful way to + + + align:start position:0% +because there's a more useful way to +think about some of our problems with + + align:start position:0% +think about some of our problems with + + + align:start position:0% +think about some of our problems with +nuclear power and whatnot is a viable + + align:start position:0% +nuclear power and whatnot is a viable + + + align:start position:0% +nuclear power and whatnot is a viable +alternative going forward first there's + + align:start position:0% +alternative going forward first there's + + + align:start position:0% +alternative going forward first there's +the problem of operating and maintaining + + align:start position:0% +the problem of operating and maintaining + + + align:start position:0% +the problem of operating and maintaining +the existing nuclear Fleet alignment + + align:start position:0% +the existing nuclear Fleet alignment + + + align:start position:0% +the existing nuclear Fleet alignment +2012 article about Diablo Canyon Hot + + align:start position:0% +2012 article about Diablo Canyon Hot + + + align:start position:0% +2012 article about Diablo Canyon Hot +thoughts on the problems with keeping + + align:start position:0% +thoughts on the problems with keeping + + + align:start position:0% +thoughts on the problems with keeping +that Diablo Canyon open having said that + + align:start position:0% +that Diablo Canyon open having said that + + + align:start position:0% +that Diablo Canyon open having said that +the state of California and the + + align:start position:0% +the state of California and the + + + align:start position:0% +the state of California and the +governors just recently + + align:start position:0% +governors just recently + + + align:start position:0% +governors just recently +reversed his position on trying to close + + align:start position:0% +reversed his position on trying to close + + + align:start position:0% +reversed his position on trying to close +the album Canyon because Diablo Canyon + + align:start position:0% +the album Canyon because Diablo Canyon + + + align:start position:0% +the album Canyon because Diablo Canyon +has to stay open to essentially provide + + align:start position:0% +has to stay open to essentially provide + + + align:start position:0% +has to stay open to essentially provide +a large Department of the state's + + align:start position:0% +a large Department of the state's + + + align:start position:0% +a large Department of the state's +renewable energy or clean energy and + + align:start position:0% +renewable energy or clean energy and + + + align:start position:0% +renewable energy or clean energy and +resources to meet their low carbon goals + + align:start position:0% +resources to meet their low carbon goals + + + align:start position:0% +resources to meet their low carbon goals +so we know we can operate maintain the + + align:start position:0% +so we know we can operate maintain the + + + align:start position:0% +so we know we can operate maintain the +existing new group that we have with + + align:start position:0% +existing new group that we have with + + + align:start position:0% +existing new group that we have with +some modification we know there's an + + align:start position:0% +some modification we know there's an + + + align:start position:0% +some modification we know there's an +existing risks but more recently a lot + + align:start position:0% +existing risks but more recently a lot + + + align:start position:0% +existing risks but more recently a lot +of environmentalists and policy analysts + + align:start position:0% +of environmentalists and policy analysts + + + align:start position:0% +of environmentalists and policy analysts +have come around to the idea of trying + + align:start position:0% +have come around to the idea of trying + + + align:start position:0% +have come around to the idea of trying +to operating and maintaining the + + align:start position:0% +to operating and maintaining the + + + align:start position:0% +to operating and maintaining the +existing particular Fleet + + align:start position:0% +existing particular Fleet + + + align:start position:0% +existing particular Fleet +here's the question of should we try to + + align:start position:0% +here's the question of should we try to + + + align:start position:0% +here's the question of should we try to +build new nuclear power plants with our + + align:start position:0% +build new nuclear power plants with our + + + align:start position:0% +build new nuclear power plants with our +existing technology and + + align:start position:0% +existing technology and + + + align:start position:0% +existing technology and +um mechanisms we have two new nuclear + + align:start position:0% +um mechanisms we have two new nuclear + + + align:start position:0% +um mechanisms we have two new nuclear +power plants in North constructing the + + align:start position:0% +power plants in North constructing the + + + align:start position:0% +power plants in North constructing the +us both in the south + + align:start position:0% +us both in the south + + + align:start position:0% +us both in the south +currently I think one is nine billion + + align:start position:0% +currently I think one is nine billion + + + align:start position:0% +currently I think one is nine billion +dollars over budget I'm not sure how + + align:start position:0% +dollars over budget I'm not sure how + + + align:start position:0% +dollars over budget I'm not sure how +much the other one is over budget + + align:start position:0% +much the other one is over budget + + + align:start position:0% +much the other one is over budget +there's the Vogel power plant and + + align:start position:0% +there's the Vogel power plant and + + + align:start position:0% +there's the Vogel power plant and +there's one in South Carolina also + + align:start position:0% +there's one in South Carolina also + + + align:start position:0% +there's one in South Carolina also +that's also considerably over budget the + + align:start position:0% +that's also considerably over budget the + + + align:start position:0% +that's also considerably over budget the +absolutely of nuclear power plants are + + align:start position:0% +absolutely of nuclear power plants are + + + align:start position:0% +absolutely of nuclear power plants are +the path of building nuclear power + + align:start position:0% +the path of building nuclear power + + + align:start position:0% +the path of building nuclear power +plants under budget or at least within + + align:start position:0% +plants under budget or at least within + + + align:start position:0% +plants under budget or at least within +budget has been terrible with our + + align:start position:0% +budget has been terrible with our + + + align:start position:0% +budget has been terrible with our +existing technology + + align:start position:0% +existing technology + + + align:start position:0% +existing technology +of course a third possibility is to + + align:start position:0% +of course a third possibility is to + + + align:start position:0% +of course a third possibility is to +build new nuclear with new technology + + align:start position:0% +build new nuclear with new technology + + + align:start position:0% +build new nuclear with new technology +and this is the alternative of small + + align:start position:0% +and this is the alternative of small + + + align:start position:0% +and this is the alternative of small +modular reactors that are quite quite + + align:start position:0% +modular reactors that are quite quite + + + align:start position:0% +modular reactors that are quite quite +often counted by nuclear enthusiasts + + align:start position:0% +often counted by nuclear enthusiasts + + + align:start position:0% +often counted by nuclear enthusiasts +this is something that needs to be + + align:start position:0% +this is something that needs to be + + + align:start position:0% +this is something that needs to be +researched it needs to be proven out + + align:start position:0% +researched it needs to be proven out + + + align:start position:0% +researched it needs to be proven out +these are all different problems we need + + align:start position:0% +these are all different problems we need + + + align:start position:0% +these are all different problems we need +to solve with nuclear power they're all + + align:start position:0% +to solve with nuclear power they're all + + + align:start position:0% +to solve with nuclear power they're all +possible solutions + + align:start position:0% +possible solutions + + + align:start position:0% +possible solutions +some uh for example the first one is + + align:start position:0% +some uh for example the first one is + + + align:start position:0% +some uh for example the first one is +probably the easiest to achieve the + + align:start position:0% +probably the easiest to achieve the + + + align:start position:0% +probably the easiest to achieve the +second one we have a terrible history + + align:start position:0% +second one we have a terrible history + + + align:start position:0% +second one we have a terrible history +with the third we would probably need to + + align:start position:0% +with the third we would probably need to + + + align:start position:0% +with the third we would probably need to +research the seeds I think possible to + + align:start position:0% +research the seeds I think possible to + + + align:start position:0% +research the seeds I think possible to +build many nuclear power plants with new + + align:start position:0% +build many nuclear power plants with new + + + align:start position:0% +build many nuclear power plants with new +technology in a more cost effective way + + align:start position:0% +technology in a more cost effective way + + + align:start position:0% +technology in a more cost effective way +but to give you a sense of some of my + + align:start position:0% +but to give you a sense of some of my + + + align:start position:0% +but to give you a sense of some of my +skepticism about nuclear I'm open to the + + align:start position:0% +skepticism about nuclear I'm open to the + + + align:start position:0% +skepticism about nuclear I'm open to the +idea but skeptical because of the past + + align:start position:0% +idea but skeptical because of the past + + + align:start position:0% +idea but skeptical because of the past +history we have in nuclear empowerment + + align:start position:0% +history we have in nuclear empowerment + + + align:start position:0% +history we have in nuclear empowerment +so let me show you some of the problems + + align:start position:0% +so let me show you some of the problems + + + align:start position:0% +so let me show you some of the problems +we've had nuclear power plants and why + + align:start position:0% +we've had nuclear power plants and why + + + align:start position:0% +we've had nuclear power plants and why +they may be out competed by new + + align:start position:0% +they may be out competed by new + + + align:start position:0% +they may be out competed by new +renewable resources + + align:start position:0% +renewable resources + + + align:start position:0% +renewable resources +if you look at this is a a fairly nice + + align:start position:0% +if you look at this is a a fairly nice + + + align:start position:0% +if you look at this is a a fairly nice +set of graphs from our world in data it + + align:start position:0% +set of graphs from our world in data it + + + align:start position:0% +set of graphs from our world in data it +shows the price electricity from new + + align:start position:0% +shows the price electricity from new + + + align:start position:0% +shows the price electricity from new +power plants this is expressed in terms + + align:start position:0% +power plants this is expressed in terms + + + align:start position:0% +power plants this is expressed in terms +of the levelized costs and energy + + align:start position:0% +of the levelized costs and energy + + + align:start position:0% +of the levelized costs and energy +something we'll talk about in a few + + align:start position:0% +something we'll talk about in a few + + + align:start position:0% +something we'll talk about in a few +lectures from now and it shows in 2009 + + align:start position:0% +lectures from now and it shows in 2009 + + + align:start position:0% +lectures from now and it shows in 2009 +on a per unit basis gas peaking plants + + align:start position:0% +on a per unit basis gas peaking plants + + + align:start position:0% +on a per unit basis gas peaking plants +declined from 275 dollars to 175 dollars + + align:start position:0% +declined from 275 dollars to 175 dollars + + + align:start position:0% +declined from 275 dollars to 175 dollars +uh gas combined cycle plants if you + + align:start position:0% +uh gas combined cycle plants if you + + + align:start position:0% +uh gas combined cycle plants if you +climb from 83 dollars to fifty six + + align:start position:0% +climb from 83 dollars to fifty six + + + align:start position:0% +climb from 83 dollars to fifty six +dollars the problem is coal-fired power + + align:start position:0% +dollars the problem is coal-fired power + + + align:start position:0% +dollars the problem is coal-fired power +plants essentially stayed stable in + + align:start position:0% +plants essentially stayed stable in + + + align:start position:0% +plants essentially stayed stable in +terms of costs over this decade and + + align:start position:0% +terms of costs over this decade and + + + align:start position:0% +terms of costs over this decade and +nuclear power plants actually increased + + align:start position:0% +nuclear power plants actually increased + + + align:start position:0% +nuclear power plants actually increased +by 26 from 123 per unit of power 155 + + align:start position:0% +by 26 from 123 per unit of power 155 + + + align:start position:0% +by 26 from 123 per unit of power 155 +which is to say that basically these two + + align:start position:0% +which is to say that basically these two + + + align:start position:0% +which is to say that basically these two +natural gas based Technologies got + + align:start position:0% +natural gas based Technologies got + + + align:start position:0% +natural gas based Technologies got +cheaper all stayed the same and you + + align:start position:0% +cheaper all stayed the same and you + + + align:start position:0% +cheaper all stayed the same and you +could have got more expensive over the + + align:start position:0% +could have got more expensive over the + + + align:start position:0% +could have got more expensive over the +last decade obviously not making nuclear + + align:start position:0% +last decade obviously not making nuclear + + + align:start position:0% +last decade obviously not making nuclear +power nearly as competitive as before + + align:start position:0% +power nearly as competitive as before + + + align:start position:0% +power nearly as competitive as before +even though nuclear power is cleaner in + + align:start position:0% +even though nuclear power is cleaner in + + + align:start position:0% +even though nuclear power is cleaner in +many ways than not the gas + + align:start position:0% +many ways than not the gas + + + align:start position:0% +many ways than not the gas +what the article about is about mostudo + + align:start position:0% +what the article about is about mostudo + + + align:start position:0% +what the article about is about mostudo +is the fact the price of Solar modules + + align:start position:0% +is the fact the price of Solar modules + + + align:start position:0% +is the fact the price of Solar modules +has decreased by 99.6 since 1976. this + + align:start position:0% +has decreased by 99.6 since 1976. this + + + align:start position:0% +has decreased by 99.6 since 1976. this +essentially shows a steady March you + + align:start position:0% +essentially shows a steady March you + + + align:start position:0% +essentially shows a steady March you +might notice the vertical axis and the + + align:start position:0% +might notice the vertical axis and the + + + align:start position:0% +might notice the vertical axis and the +horizontal axes are both logarithmic + + align:start position:0% +horizontal axes are both logarithmic + + + align:start position:0% +horizontal axes are both logarithmic +scales so every time you go down one of + + align:start position:0% +scales so every time you go down one of + + + align:start position:0% +scales so every time you go down one of +these blocks it's basically having in + + align:start position:0% +these blocks it's basically having in + + + align:start position:0% +these blocks it's basically having in +place and as this graph points out with + + align:start position:0% +place and as this graph points out with + + + align:start position:0% +place and as this graph points out with +each doubling of capacity along the + + align:start position:0% +each doubling of capacity along the + + + align:start position:0% +each doubling of capacity along the +horizontal axis the price of Solar + + align:start position:0% +horizontal axis the price of Solar + + + align:start position:0% +horizontal axis the price of Solar +module dropped on average by 20 this is + + align:start position:0% +module dropped on average by 20 this is + + + align:start position:0% +module dropped on average by 20 this is +called The Learning rate or learning + + align:start position:0% +called The Learning rate or learning + + + align:start position:0% +called The Learning rate or learning +curve so the learning curve is + + align:start position:0% +curve so the learning curve is + + + align:start position:0% +curve so the learning curve is +essentially every time you double how + + align:start position:0% +essentially every time you double how + + + align:start position:0% +essentially every time you double how +much you make of it the price go down + + align:start position:0% +much you make of it the price go down + + + align:start position:0% +much you make of it the price go down +this is also referred to as rights law + + align:start position:0% +this is also referred to as rights law + + + align:start position:0% +this is also referred to as rights law +which has been studied quite a bit by + + align:start position:0% +which has been studied quite a bit by + + + align:start position:0% +which has been studied quite a bit by +Jessica transck especially my MIT + + align:start position:0% +Jessica transck especially my MIT + + + align:start position:0% +Jessica transck especially my MIT +colleague and idss + + align:start position:0% +colleague and idss + + + align:start position:0% +colleague and idss +and some of the theory around why this + + align:start position:0% +and some of the theory around why this + + + align:start position:0% +and some of the theory around why this +occurs is that as we have more + + align:start position:0% +occurs is that as we have more + + + align:start position:0% +occurs is that as we have more +deployment more and more competition or + + align:start position:0% +deployment more and more competition or + + + align:start position:0% +deployment more and more competition or +there's prices fall because there's more + + align:start position:0% +there's prices fall because there's more + + + align:start position:0% +there's prices fall because there's more +deployment it becomes competitive and + + align:start position:0% +deployment it becomes competitive and + + + align:start position:0% +deployment it becomes competitive and +you markets that increases demand and + + align:start position:0% +you markets that increases demand and + + + align:start position:0% +you markets that increases demand and +overcomes a virtuous circle where more + + align:start position:0% +overcomes a virtuous circle where more + + + align:start position:0% +overcomes a virtuous circle where more +deployment makes things cheaper on a per + + align:start position:0% +deployment makes things cheaper on a per + + + align:start position:0% +deployment makes things cheaper on a per +unit basis the more you make the cheaper + + align:start position:0% +unit basis the more you make the cheaper + + + align:start position:0% +unit basis the more you make the cheaper +it gets and Jessica Transit has written + + align:start position:0% +it gets and Jessica Transit has written + + + align:start position:0% +it gets and Jessica Transit has written +another paper about why the modularity + + align:start position:0% +another paper about why the modularity + + + align:start position:0% +another paper about why the modularity +of these systems across not only the + + align:start position:0% +of these systems across not only the + + + align:start position:0% +of these systems across not only the +solar cells the balances system has made + + align:start position:0% +solar cells the balances system has made + + + align:start position:0% +solar cells the balances system has made +these things get cheaper and she + + align:start position:0% +these things get cheaper and she + + + align:start position:0% +these things get cheaper and she +analyzes the different policy drivers + + align:start position:0% +analyzes the different policy drivers + + + align:start position:0% +analyzes the different policy drivers +ranging from German feed Insurance to + + align:start position:0% +ranging from German feed Insurance to + + + align:start position:0% +ranging from German feed Insurance to +Chinese investment in large portable TIG + + align:start position:0% +Chinese investment in large portable TIG + + + align:start position:0% +Chinese investment in large portable TIG +cell factories and policy drivers from + + align:start position:0% +cell factories and policy drivers from + + + align:start position:0% +cell factories and policy drivers from +the US Spain and other countries + + align:start position:0% +the US Spain and other countries + + + align:start position:0% +the US Spain and other countries +but the important point to take home + + align:start position:0% +but the important point to take home + + + align:start position:0% +but the important point to take home +from this is that you know we have a + + align:start position:0% +from this is that you know we have a + + + align:start position:0% +from this is that you know we have a +learning rate of about 36 percent here + + align:start position:0% +learning rate of about 36 percent here + + + align:start position:0% +learning rate of about 36 percent here +in this graph for solar PV + + align:start position:0% +in this graph for solar PV + + + align:start position:0% +in this graph for solar PV +we have a aggressively not as fast + + align:start position:0% +we have a aggressively not as fast + + + align:start position:0% +we have a aggressively not as fast +learning rate for offshore wind with + + align:start position:0% +learning rate for offshore wind with + + + align:start position:0% +learning rate for offshore wind with +steady decreases in the cost of optical + + align:start position:0% +steady decreases in the cost of optical + + + align:start position:0% +steady decreases in the cost of optical +wind you can see we're currently at low + + align:start position:0% +wind you can see we're currently at low + + + align:start position:0% +wind you can see we're currently at low +levels of deployment above throw in + + align:start position:0% +levels of deployment above throw in + + + align:start position:0% +levels of deployment above throw in +compared to new technologies onshore + + align:start position:0% +compared to new technologies onshore + + + align:start position:0% +compared to new technologies onshore +wind is much larger at deployment and + + align:start position:0% +wind is much larger at deployment and + + + align:start position:0% +wind is much larger at deployment and +much cheaper than off-pro wind that + + align:start position:0% +much cheaper than off-pro wind that + + + align:start position:0% +much cheaper than off-pro wind that +learning rate has also been comparable + + align:start position:0% +learning rate has also been comparable + + + align:start position:0% +learning rate has also been comparable +or in the same ballpark as solar PV + + align:start position:0% +or in the same ballpark as solar PV + + + align:start position:0% +or in the same ballpark as solar PV +look hole has no learning rate whole has + + align:start position:0% +look hole has no learning rate whole has + + + align:start position:0% +look hole has no learning rate whole has +not gotten significantly cheaper over + + align:start position:0% +not gotten significantly cheaper over + + + align:start position:0% +not gotten significantly cheaper over +the last decade and as we pointed out in + + align:start position:0% +the last decade and as we pointed out in + + + align:start position:0% +the last decade and as we pointed out in +previous graph Newport Powers actually + + align:start position:0% +previous graph Newport Powers actually + + + align:start position:0% +previous graph Newport Powers actually +gotten more expensive over time and so + + align:start position:0% +gotten more expensive over time and so + + + align:start position:0% +gotten more expensive over time and so +what I want to encourage you to think + + align:start position:0% +what I want to encourage you to think + + + align:start position:0% +what I want to encourage you to think +about is this in a competitive market + + align:start position:0% +about is this in a competitive market + + + align:start position:0% +about is this in a competitive market +which is to say that nuclear power is + + align:start position:0% +which is to say that nuclear power is + + + align:start position:0% +which is to say that nuclear power is +getting more expensive and everything + + align:start position:0% +getting more expensive and everything + + + align:start position:0% +getting more expensive and everything +else in solar and wind are getting + + align:start position:0% +else in solar and wind are getting + + + align:start position:0% +else in solar and wind are getting +cheaper faster the new carbon for + + align:start position:0% +cheaper faster the new carbon for + + + align:start position:0% +cheaper faster the new carbon for +nuclear is no longer simply declining it + + align:start position:0% +nuclear is no longer simply declining it + + + align:start position:0% +nuclear is no longer simply declining it +actually has to be behind at a rate at a + + align:start position:0% +actually has to be behind at a rate at a + + + align:start position:0% +actually has to be behind at a rate at a +comparable price that compete with solar + + align:start position:0% +comparable price that compete with solar + + + align:start position:0% +comparable price that compete with solar +wind and so so the Sepulveda L 2018 + + align:start position:0% +wind and so so the Sepulveda L 2018 + + + align:start position:0% +wind and so so the Sepulveda L 2018 +paper argues the cost of the system will + + align:start position:0% +paper argues the cost of the system will + + + align:start position:0% +paper argues the cost of the system will +be much higher if we don't have Fern + + align:start position:0% +be much higher if we don't have Fern + + + align:start position:0% +be much higher if we don't have Fern +green resources such as nuclear energy + + align:start position:0% +green resources such as nuclear energy + + + align:start position:0% +green resources such as nuclear energy +or natural gas power plants that include + + align:start position:0% +or natural gas power plants that include + + + align:start position:0% +or natural gas power plants that include +carbon Capital storage or a large fiber + + align:start position:0% +carbon Capital storage or a large fiber + + + align:start position:0% +carbon Capital storage or a large fiber +resources but you know this picture is + + align:start position:0% +resources but you know this picture is + + + align:start position:0% +resources but you know this picture is +going to change over time and they do a + + align:start position:0% +going to change over time and they do a + + + align:start position:0% +going to change over time and they do a +lot of modeling this paper to show that + + align:start position:0% +lot of modeling this paper to show that + + + align:start position:0% +lot of modeling this paper to show that +we need nuclear energy to keep the cost + + align:start position:0% +we need nuclear energy to keep the cost + + + align:start position:0% +we need nuclear energy to keep the cost +of decompartmentation low anywhere + + align:start position:0% +of decompartmentation low anywhere + + + align:start position:0% +of decompartmentation low anywhere +anywhere from 10 to 60 percent lower + + align:start position:0% +anywhere from 10 to 60 percent lower + + + align:start position:0% +anywhere from 10 to 60 percent lower +having said that there's also other + + align:start position:0% +having said that there's also other + + + align:start position:0% +having said that there's also other +reports and other analysts looking at + + align:start position:0% +reports and other analysts looking at + + + align:start position:0% +reports and other analysts looking at +the idea that solar may get so cheap so + + align:start position:0% +the idea that solar may get so cheap so + + + align:start position:0% +the idea that solar may get so cheap so +quickly that we simply need to build + + align:start position:0% +quickly that we simply need to build + + + align:start position:0% +quickly that we simply need to build +twice as much of the uh to twice as much + + align:start position:0% +twice as much of the uh to twice as much + + + align:start position:0% +twice as much of the uh to twice as much +capacity as we need in other words for + + align:start position:0% +capacity as we need in other words for + + + align:start position:0% +capacity as we need in other words for +the times of year we don't have that + + align:start position:0% +the times of year we don't have that + + + align:start position:0% +the times of year we don't have that +much sun we simply build twice as many + + align:start position:0% +much sun we simply build twice as many + + + align:start position:0% +much sun we simply build twice as many +solar panels in order to try to meet + + align:start position:0% +solar panels in order to try to meet + + + align:start position:0% +solar panels in order to try to meet +that winter load or winter demand + + align:start position:0% +that winter load or winter demand + + + align:start position:0% +that winter load or winter demand +there's different possibilities there'll + + align:start position:0% +there's different possibilities there'll + + + align:start position:0% +there's different possibilities there'll +be different forecasts going forward but + + align:start position:0% +be different forecasts going forward but + + + align:start position:0% +be different forecasts going forward but +for nuclear energy it's a moving Target + + align:start position:0% +for nuclear energy it's a moving Target + + + align:start position:0% +for nuclear energy it's a moving Target +not only does the price of nuclear + + align:start position:0% +not only does the price of nuclear + + + align:start position:0% +not only does the price of nuclear +energy have to come down it has to meet + + align:start position:0% +energy have to come down it has to meet + + + align:start position:0% +energy have to come down it has to meet +targets of offshore wind and solar + + align:start position:0% +targets of offshore wind and solar + + + align:start position:0% +targets of offshore wind and solar +they're getting cheaper all the time + + align:start position:0% +they're getting cheaper all the time + + + align:start position:0% +they're getting cheaper all the time +batteries are also getting cheaper + + align:start position:0% +batteries are also getting cheaper + + + align:start position:0% +batteries are also getting cheaper +electrolyzers which is the technology by + + align:start position:0% +electrolyzers which is the technology by + + + align:start position:0% +electrolyzers which is the technology by +which we take electricity and create + + align:start position:0% +which we take electricity and create + + + align:start position:0% +which we take electricity and create +hydrogen is also getting cheaper so + + align:start position:0% +hydrogen is also getting cheaper so + + + align:start position:0% +hydrogen is also getting cheaper so +these are all kind of fluid Technologies + + align:start position:0% +these are all kind of fluid Technologies + + + align:start position:0% +these are all kind of fluid Technologies +and this is why we need the + + align:start position:0% +and this is why we need the + + + align:start position:0% +and this is why we need the +technological forecasting to show us how + + align:start position:0% +technological forecasting to show us how + + + align:start position:0% +technological forecasting to show us how +much more expensive it may be having + + align:start position:0% +much more expensive it may be having + + + align:start position:0% +much more expensive it may be having +said that because we know there's other + + align:start position:0% +said that because we know there's other + + + align:start position:0% +said that because we know there's other +ancillary effects we have land use + + align:start position:0% +ancillary effects we have land use + + + align:start position:0% +ancillary effects we have land use +obstacles we have rate of + + align:start position:0% +obstacles we have rate of + + + align:start position:0% +obstacles we have rate of +electrification of some of our + + align:start position:0% +electrification of some of our + + + align:start position:0% +electrification of some of our +Technologies we know we have policy + + align:start position:0% +Technologies we know we have policy + + + align:start position:0% +Technologies we know we have policy +barriers it's not clear necessarily if + + align:start position:0% +barriers it's not clear necessarily if + + + align:start position:0% +barriers it's not clear necessarily if +Austin is simply going to win out for + + align:start position:0% +Austin is simply going to win out for + + + align:start position:0% +Austin is simply going to win out for +some technologies over others but we + + align:start position:0% +some technologies over others but we + + + align:start position:0% +some technologies over others but we +know that the technologies that are + + align:start position:0% +know that the technologies that are + + + align:start position:0% +know that the technologies that are +getting more expensive over time are + + align:start position:0% +getting more expensive over time are + + + align:start position:0% +getting more expensive over time are +going to have a hard time competing for + + align:start position:0% +going to have a hard time competing for + + + align:start position:0% +going to have a hard time competing for +the Technologies getting cheaper over + + align:start position:0% +the Technologies getting cheaper over + + + align:start position:0% +the Technologies getting cheaper over +time + + align:start position:0% +time + + + align:start position:0% +time +uh so just to reinforce the point of + + align:start position:0% +uh so just to reinforce the point of + + + align:start position:0% +uh so just to reinforce the point of +electrification the price and Market + + align:start position:0% +electrification the price and Market + + + align:start position:0% +electrification the price and Market +size lithium ion battery since 1992 also + + align:start position:0% +size lithium ion battery since 1992 also + + + align:start position:0% +size lithium ion battery since 1992 also +exhibits a very fast learning rate the + + align:start position:0% +exhibits a very fast learning rate the + + + align:start position:0% +exhibits a very fast learning rate the +prices have declined by an average of + + align:start position:0% +prices have declined by an average of + + + align:start position:0% +prices have declined by an average of +18.9 for every doubling and capacity of + + align:start position:0% +18.9 for every doubling and capacity of + + + align:start position:0% +18.9 for every doubling and capacity of +batteries this shows you the steady + + align:start position:0% +batteries this shows you the steady + + + align:start position:0% +batteries this shows you the steady +March of battery prices going down which + + align:start position:0% +March of battery prices going down which + + + align:start position:0% +March of battery prices going down which +is why we're getting successively + + align:start position:0% +is why we're getting successively + + + align:start position:0% +is why we're getting successively +cheaper Generations electric cars and + + align:start position:0% +cheaper Generations electric cars and + + + align:start position:0% +cheaper Generations electric cars and +pretty much Lithium-ion batteries and + + align:start position:0% +pretty much Lithium-ion batteries and + + + align:start position:0% +pretty much Lithium-ion batteries and +everything uh you may we all know that + + align:start position:0% +everything uh you may we all know that + + + align:start position:0% +everything uh you may we all know that +our phones have gotten more powerful but + + align:start position:0% +our phones have gotten more powerful but + + + align:start position:0% +our phones have gotten more powerful but +now you can buy Power Banks Flags blades + + align:start position:0% +now you can buy Power Banks Flags blades + + + align:start position:0% +now you can buy Power Banks Flags blades +pretty much everything has an Olympia on + + align:start position:0% +pretty much everything has an Olympia on + + + align:start position:0% +pretty much everything has an Olympia on +battery that can replace a small + + align:start position:0% +battery that can replace a small + + + align:start position:0% +battery that can replace a small +combustion engine like leaf blowers very + + align:start position:0% +combustion engine like leaf blowers very + + + align:start position:0% +combustion engine like leaf blowers very +easily or electrical appliances very + + align:start position:0% +easily or electrical appliances very + + + align:start position:0% +easily or electrical appliances very +easily + + align:start position:0% +easily + + + align:start position:0% +easily +uh bringing us back to just the idea of + + align:start position:0% +uh bringing us back to just the idea of + + + align:start position:0% +uh bringing us back to just the idea of +costs and nuclear this is a paper + + align:start position:0% +costs and nuclear this is a paper + + + align:start position:0% +costs and nuclear this is a paper +written at MIT also in 2020 it's about + + align:start position:0% +written at MIT also in 2020 it's about + + + align:start position:0% +written at MIT also in 2020 it's about +sources of costs overrun in the nuclear + + align:start position:0% +sources of costs overrun in the nuclear + + + align:start position:0% +sources of costs overrun in the nuclear +power plant construction all spread New + + align:start position:0% +power plant construction all spread New + + + align:start position:0% +power plant construction all spread New +York Bridge engineering design and this + + align:start position:0% +York Bridge engineering design and this + + + align:start position:0% +York Bridge engineering design and this +is written by a student I had in this + + align:start position:0% +is written by a student I had in this + + + align:start position:0% +is written by a student I had in this +class at Philip eastgates and regulated + + align:start position:0% +class at Philip eastgates and regulated + + + align:start position:0% +class at Philip eastgates and regulated +Clement who is also a postdoc and grad + + align:start position:0% +Clement who is also a postdoc and grad + + + align:start position:0% +Clement who is also a postdoc and grad +student at MIT and all from Jessica + + align:start position:0% +student at MIT and all from Jessica + + + align:start position:0% +student at MIT and all from Jessica +working with James McNerney Jacob + + align:start position:0% +working with James McNerney Jacob + + + align:start position:0% +working with James McNerney Jacob +buongiorno and Jessica Transit here at + + align:start position:0% +buongiorno and Jessica Transit here at + + + align:start position:0% +buongiorno and Jessica Transit here at +IIT + + align:start position:0% +IIT + + + align:start position:0% +IIT +this paper essentially studied why + + align:start position:0% +this paper essentially studied why + + + align:start position:0% +this paper essentially studied why +office overruns have been occurring in + + align:start position:0% +office overruns have been occurring in + + + align:start position:0% +office overruns have been occurring in +nuclear power plants it finds that it + + align:start position:0% +nuclear power plants it finds that it + + + align:start position:0% +nuclear power plants it finds that it +has a negative learning rate nuclear + + align:start position:0% +has a negative learning rate nuclear + + + align:start position:0% +has a negative learning rate nuclear +Construction in the US has gotten + + align:start position:0% +Construction in the US has gotten + + + align:start position:0% +Construction in the US has gotten +steadily more expensive over time as the + + align:start position:0% +steadily more expensive over time as the + + + align:start position:0% +steadily more expensive over time as the +capacity has gone up this is a negative + + align:start position:0% +capacity has gone up this is a negative + + + align:start position:0% +capacity has gone up this is a negative +learning rate it shows for all these + + align:start position:0% +learning rate it shows for all these + + + align:start position:0% +learning rate it shows for all these +different technology types the override + + align:start position:0% +different technology types the override + + + align:start position:0% +different technology types the override +construction deposits steadily increased + + align:start position:0% +construction deposits steadily increased + + + align:start position:0% +construction deposits steadily increased +the + + align:start position:0% +the + + + align:start position:0% +the +analysis of why these prices have + + align:start position:0% +analysis of why these prices have + + + align:start position:0% +analysis of why these prices have +increased space they showed someone's + + align:start position:0% +increased space they showed someone's + + + align:start position:0% +increased space they showed someone's +across the board increase and all the + + align:start position:0% +across the board increase and all the + + + align:start position:0% +across the board increase and all the +different components of a nuclear power + + align:start position:0% +different components of a nuclear power + + + align:start position:0% +different components of a nuclear power +plant the blue bars are the direct cost + + align:start position:0% +plant the blue bars are the direct cost + + + align:start position:0% +plant the blue bars are the direct cost +of let's say the nuclear steam Supply + + align:start position:0% +of let's say the nuclear steam Supply + + + align:start position:0% +of let's say the nuclear steam Supply +system but the indirect cost is the + + align:start position:0% +system but the indirect cost is the + + + align:start position:0% +system but the indirect cost is the +essentially the soft possible the labor + + align:start position:0% +essentially the soft possible the labor + + + align:start position:0% +essentially the soft possible the labor +intensive components around building + + align:start position:0% +intensive components around building + + + align:start position:0% +intensive components around building +these Technologies you can see that this + + align:start position:0% +these Technologies you can see that this + + + align:start position:0% +these Technologies you can see that this +is a pretty much a steady increase + + align:start position:0% +is a pretty much a steady increase + + + align:start position:0% +is a pretty much a steady increase +across the board everything costs more + + align:start position:0% +across the board everything costs more + + + align:start position:0% +across the board everything costs more +hardly everything costs more because of + + align:start position:0% +hardly everything costs more because of + + + align:start position:0% +hardly everything costs more because of +these indirect costs or soft costs it is + + align:start position:0% +these indirect costs or soft costs it is + + + align:start position:0% +these indirect costs or soft costs it is +not clearly necessarily again if our + + align:start position:0% +not clearly necessarily again if our + + + align:start position:0% +not clearly necessarily again if our +current way way of delivering nuclear + + align:start position:0% +current way way of delivering nuclear + + + align:start position:0% +current way way of delivering nuclear +power plants is going to be effective we + + align:start position:0% +power plants is going to be effective we + + + align:start position:0% +power plants is going to be effective we +obviously need to rethink how we deliver + + align:start position:0% +obviously need to rethink how we deliver + + + align:start position:0% +obviously need to rethink how we deliver +nuclear power plants and this is another + + align:start position:0% +nuclear power plants and this is another + + + align:start position:0% +nuclear power plants and this is another +paper by Arnold grubler a fairly famous + + align:start position:0% +paper by Arnold grubler a fairly famous + + + align:start position:0% +paper by Arnold grubler a fairly famous +analyst this is written about 10 or 12 + + align:start position:0% +analyst this is written about 10 or 12 + + + align:start position:0% +analyst this is written about 10 or 12 +years ago but this takes the French + + align:start position:0% +years ago but this takes the French + + + align:start position:0% +years ago but this takes the French +nuclear industry which is basically been + + align:start position:0% +nuclear industry which is basically been + + + align:start position:0% +nuclear industry which is basically been +always touted as the most successful + + align:start position:0% +always touted as the most successful + + + align:start position:0% +always touted as the most successful +nuclear energy in the world and again + + align:start position:0% +nuclear energy in the world and again + + + align:start position:0% +nuclear energy in the world and again +essentially looks at data from this + + align:start position:0% +essentially looks at data from this + + + align:start position:0% +essentially looks at data from this +program and finds negative learning by + + align:start position:0% +program and finds negative learning by + + + align:start position:0% +program and finds negative learning by +doing it reviews the history and + + align:start position:0% +doing it reviews the history and + + + align:start position:0% +doing it reviews the history and +economics of the French pwr program + + align:start position:0% +economics of the French pwr program + + + align:start position:0% +economics of the French pwr program +which is considered the most successful + + align:start position:0% +which is considered the most successful + + + align:start position:0% +which is considered the most successful +nuclear skill of experience in that + + align:start position:0% +nuclear skill of experience in that + + + align:start position:0% +nuclear skill of experience in that +country + + align:start position:0% +country + + + align:start position:0% +country +but drawing on largely unknown public + + align:start position:0% +but drawing on largely unknown public + + + align:start position:0% +but drawing on largely unknown public +records the paper reveals for the first + + align:start position:0% +records the paper reveals for the first + + + align:start position:0% +records the paper reveals for the first +time both absolute as well as yearly and + + align:start position:0% +time both absolute as well as yearly and + + + align:start position:0% +time both absolute as well as yearly and +specific reactive costs and evolution + + align:start position:0% +specific reactive costs and evolution + + + align:start position:0% +specific reactive costs and evolution +over time the most significant finding + + align:start position:0% +over time the most significant finding + + + align:start position:0% +over time the most significant finding +is that even in the most successful + + align:start position:0% +is that even in the most successful + + + align:start position:0% +is that even in the most successful +nuclear scale up is characterized by + + align:start position:0% +nuclear scale up is characterized by + + + align:start position:0% +nuclear scale up is characterized by +substantial escalation of real-time + + align:start position:0% +substantial escalation of real-time + + + align:start position:0% +substantial escalation of real-time +construction costs in other words we + + align:start position:0% +construction costs in other words we + + + align:start position:0% +construction costs in other words we +still don't have very much evidence over + + align:start position:0% +still don't have very much evidence over + + + align:start position:0% +still don't have very much evidence over +the last 40 or 50 years that nuclear + + align:start position:0% +the last 40 or 50 years that nuclear + + + align:start position:0% +the last 40 or 50 years that nuclear +power plants get cheaper over time they + + align:start position:0% +power plants get cheaper over time they + + + align:start position:0% +power plants get cheaper over time they +seem to get more expensive over time so + + align:start position:0% +seem to get more expensive over time so + + + align:start position:0% +seem to get more expensive over time so +again while I'm open to the idea of + + align:start position:0% +again while I'm open to the idea of + + + align:start position:0% +again while I'm open to the idea of +nuclear I would like to see it become + + align:start position:0% +nuclear I would like to see it become + + + align:start position:0% +nuclear I would like to see it become +cheaper before we actually think that + + align:start position:0% +cheaper before we actually think that + + + align:start position:0% +cheaper before we actually think that +it's going to be a viable uh part of our + + align:start position:0% +it's going to be a viable uh part of our + + + align:start position:0% +it's going to be a viable uh part of our +future energy system that means we + + align:start position:0% +future energy system that means we + + + align:start position:0% +future energy system that means we +should research it it does mean we + + align:start position:0% +should research it it does mean we + + + align:start position:0% +should research it it does mean we +should subsidize Research into it to try + + align:start position:0% +should subsidize Research into it to try + + + align:start position:0% +should subsidize Research into it to try +to bring it into a more cost competitive + + align:start position:0% +to bring it into a more cost competitive + + + align:start position:0% +to bring it into a more cost competitive +stance versus alternative or existing + + align:start position:0% +stance versus alternative or existing + + + align:start position:0% +stance versus alternative or existing +alternative and renewable energy + + align:start position:0% +alternative and renewable energy + + + align:start position:0% +alternative and renewable energy +resources but again we should recognize + + align:start position:0% +resources but again we should recognize + + + align:start position:0% +resources but again we should recognize +that our current costs don't make it + + align:start position:0% +that our current costs don't make it + + + align:start position:0% +that our current costs don't make it +economically viable to use nuclear power + + align:start position:0% +economically viable to use nuclear power + + + align:start position:0% +economically viable to use nuclear power +plants for the things that it's been + + align:start position:0% +plants for the things that it's been + + + align:start position:0% +plants for the things that it's been +touted for + + align:start position:0% +touted for + + + align:start position:0% +touted for +so thank you very much I look forward to + + align:start position:0% +so thank you very much I look forward to + + + align:start position:0% +so thank you very much I look forward to +our discussion in class on some of these + + align:start position:0% +our discussion in class on some of these + + + align:start position:0% +our discussion in class on some of these +themes \ No newline at end of file diff --git a/f_sNWn7zujU.txt b/f_sNWn7zujU.txt new file mode 100644 index 0000000000000000000000000000000000000000..1634144a5520a087b66131e21a7b35846fd7bd1e --- /dev/null +++ b/f_sNWn7zujU.txt @@ -0,0 +1,12673 @@ +align:start position:0% + +so last time + + align:start position:0% +so last time + + + align:start position:0% +so last time +we finished by proving + + align:start position:0% +we finished by proving + + + align:start position:0% +we finished by proving +bolzano's intermediate value theorem + + align:start position:0% + + + + align:start position:0% + +which states that a continuous function + + align:start position:0% +which states that a continuous function + + + align:start position:0% +which states that a continuous function +achieves all values in between + + align:start position:0% +achieves all values in between + + + align:start position:0% +achieves all values in between +the function evaluated at the endpoints + + align:start position:0% +the function evaluated at the endpoints + + + align:start position:0% +the function evaluated at the endpoints +so + + align:start position:0% + + + + align:start position:0% + +if i have a continuous function + + align:start position:0% + + + + align:start position:0% + +and either + + align:start position:0% + + + + align:start position:0% + +i take a value y between f of a and f of + + align:start position:0% +i take a value y between f of a and f of + + + align:start position:0% +i take a value y between f of a and f of +b so either f of a is less than f of b + + align:start position:0% +b so either f of a is less than f of b + + + align:start position:0% +b so either f of a is less than f of b +and y's in between + + align:start position:0% +and y's in between + + + align:start position:0% +and y's in between +is bigger than f of a and less than f of + + align:start position:0% +is bigger than f of a and less than f of + + + align:start position:0% +is bigger than f of a and less than f of +b + + align:start position:0% +b + + + align:start position:0% +b +or + + align:start position:0% +or + + + align:start position:0% +or +f of a is bigger than f of b but + + align:start position:0% +f of a is bigger than f of b but + + + align:start position:0% +f of a is bigger than f of b but +y is still in between them + + align:start position:0% + + + + align:start position:0% + +then there exists + + align:start position:0% + + + + align:start position:0% + +c in the interval a b + + align:start position:0% +c in the interval a b + + + align:start position:0% +c in the interval a b +so that + + align:start position:0% + + + + align:start position:0% + +f c equals y alright so every value in + + align:start position:0% +f c equals y alright so every value in + + + align:start position:0% +f c equals y alright so every value in +between f + + align:start position:0% +between f + + + align:start position:0% +between f +evaluated at the endpoints + + align:start position:0% +evaluated at the endpoints + + + align:start position:0% +evaluated at the endpoints +is achieved i drew the picture then + + align:start position:0% +is achieved i drew the picture then + + + align:start position:0% +is achieved i drew the picture then +along with this + + align:start position:0% +along with this + + + align:start position:0% +along with this +a b + + align:start position:0% + + + + align:start position:0% + +f a + + align:start position:0% + + + + align:start position:0% + +f b + + align:start position:0% +f b + + + align:start position:0% +f b +and + + align:start position:0% +and + + + align:start position:0% +and +that could be + + align:start position:0% + + + + align:start position:0% + +the function and if we take anything + + align:start position:0% + + + + align:start position:0% + +in between + + align:start position:0% +in between + + + align:start position:0% +in between +then there has to be + + align:start position:0% +then there has to be + + + align:start position:0% +then there has to be +some c + + align:start position:0% +some c + + + align:start position:0% +some c +so that f of c + + align:start position:0% +so that f of c + + + align:start position:0% +so that f of c +equals y okay at least in the picture + + align:start position:0% +equals y okay at least in the picture + + + align:start position:0% +equals y okay at least in the picture +i've drawn there's three different guys + + align:start position:0% +i've drawn there's three different guys + + + align:start position:0% +i've drawn there's three different guys +but there's always at least one + + align:start position:0% +but there's always at least one + + + align:start position:0% +but there's always at least one +okay and then um + + align:start position:0% +okay and then um + + + align:start position:0% +okay and then um +the last uh thing we talked about at the + + align:start position:0% +the last uh thing we talked about at the + + + align:start position:0% +the last uh thing we talked about at the +end of last lecture was that + + align:start position:0% +end of last lecture was that + + + align:start position:0% +end of last lecture was that +um + + align:start position:0% +um + + + align:start position:0% +um +the + + align:start position:0% +the + + + align:start position:0% +the +image of + + align:start position:0% +image of + + + align:start position:0% +image of +a bounded closed and bounded interval by + + align:start position:0% +a bounded closed and bounded interval by + + + align:start position:0% +a bounded closed and bounded interval by +a continuous function + + align:start position:0% +a continuous function + + + align:start position:0% +a continuous function +is again + + align:start position:0% +is again + + + align:start position:0% +is again +a closed and bounded interval + + align:start position:0% + + + + align:start position:0% + +where e corresponds to + + align:start position:0% +where e corresponds to + + + align:start position:0% +where e corresponds to +the absolute max of f and f corresponds + + align:start position:0% +the absolute max of f and f corresponds + + + align:start position:0% +the absolute max of f and f corresponds +so that i shouldn't call this f since we + + align:start position:0% +so that i shouldn't call this f since we + + + align:start position:0% +so that i shouldn't call this f since we +already have f being used + + align:start position:0% +already have f being used + + + align:start position:0% +already have f being used +and g + + align:start position:0% +and g + + + align:start position:0% +and g +corresponds to + + align:start position:0% + + + + align:start position:0% + +let's make it d + + align:start position:0% + + + + align:start position:0% + +corresponds to the absolute min of f + + align:start position:0% +corresponds to the absolute min of f + + + align:start position:0% +corresponds to the absolute min of f +okay so this uh + + align:start position:0% +okay so this uh + + + align:start position:0% +okay so this uh +is what we proved uh + + align:start position:0% + + + + align:start position:0% + +last time is that f of + + align:start position:0% + + + + align:start position:0% + +if f is continuous then + + align:start position:0% + + + + align:start position:0% + +there exists + + align:start position:0% +there exists + + + align:start position:0% +there exists +e d + + align:start position:0% +e d + + + align:start position:0% +e d +and r + + align:start position:0% +and r + + + align:start position:0% +and r +such that the range + + align:start position:0% +such that the range + + + align:start position:0% +such that the range +of this closed and bounded interval is + + align:start position:0% +of this closed and bounded interval is + + + align:start position:0% +of this closed and bounded interval is +again + + align:start position:0% +again + + + align:start position:0% +again +a closed and bounded interval okay so f + + align:start position:0% +a closed and bounded interval okay so f + + + align:start position:0% +a closed and bounded interval okay so f +is very well behaved + + align:start position:0% +is very well behaved + + + align:start position:0% +is very well behaved +on closed and bounded intervals + + align:start position:0% +on closed and bounded intervals + + + align:start position:0% +on closed and bounded intervals +and we'll see another way in which + + align:start position:0% +and we'll see another way in which + + + align:start position:0% +and we'll see another way in which +continuous functions are well behaved on + + align:start position:0% +continuous functions are well behaved on + + + align:start position:0% +continuous functions are well behaved on +a closed and bounded interval in just a + + align:start position:0% +a closed and bounded interval in just a + + + align:start position:0% +a closed and bounded interval in just a +second + + align:start position:0% +second + + + align:start position:0% +second +um now + + align:start position:0% + + + + align:start position:0% + +you know a simple application of + + align:start position:0% +you know a simple application of + + + align:start position:0% +you know a simple application of +the balzano immediate value intermediate + + align:start position:0% +the balzano immediate value intermediate + + + align:start position:0% +the balzano immediate value intermediate +value theorem + + align:start position:0% +value theorem + + + align:start position:0% +value theorem +is um the following + + align:start position:0% +is um the following + + + align:start position:0% +is um the following +really it's an application of that + + align:start position:0% +really it's an application of that + + + align:start position:0% +really it's an application of that +theorem that i labeled the bisection + + align:start position:0% +theorem that i labeled the bisection + + + align:start position:0% +theorem that i labeled the bisection +method but uh + + align:start position:0% +method but uh + + + align:start position:0% +method but uh +let's uh + + align:start position:0% +let's uh + + + align:start position:0% +let's uh +you know chalk that up to the bolzando + + align:start position:0% +you know chalk that up to the bolzando + + + align:start position:0% +you know chalk that up to the bolzando +intermediate value theorem + + align:start position:0% +intermediate value theorem + + + align:start position:0% +intermediate value theorem +which is the following that + + align:start position:0% + + + + align:start position:0% + +if f of x + + align:start position:0% +if f of x + + + align:start position:0% +if f of x +is + + align:start position:0% +is + + + align:start position:0% +is +any odd + + align:start position:0% + + + + align:start position:0% + +polynomial + + align:start position:0% + + + + align:start position:0% + +then + + align:start position:0% + + + + align:start position:0% + +f has + + align:start position:0% + + + + align:start position:0% + +at least one + + align:start position:0% + + + + align:start position:0% + +real root + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so any odd polynomial has at least one + + align:start position:0% +so any odd polynomial has at least one + + + align:start position:0% +so any odd polynomial has at least one +real root so by the fundamental theorem + + align:start position:0% +real root so by the fundamental theorem + + + align:start position:0% +real root so by the fundamental theorem +of algebra every polynomial has exactly + + align:start position:0% +of algebra every polynomial has exactly + + + align:start position:0% +of algebra every polynomial has exactly +n roots n corresponding to the degree of + + align:start position:0% +n roots n corresponding to the degree of + + + align:start position:0% +n roots n corresponding to the degree of +the polynomial but these roots can be + + align:start position:0% +the polynomial but these roots can be + + + align:start position:0% +the polynomial but these roots can be +complex valued okay + + align:start position:0% +complex valued okay + + + align:start position:0% +complex valued okay +uh but for odd polynomials there must be + + align:start position:0% +uh but for odd polynomials there must be + + + align:start position:0% +uh but for odd polynomials there must be +at least one real root and this is a + + align:start position:0% +at least one real root and this is a + + + align:start position:0% +at least one real root and this is a +consequence of the bolzano interview + + align:start position:0% +consequence of the bolzano interview + + + align:start position:0% +consequence of the bolzano interview +intermediate value theorem but instead + + align:start position:0% +intermediate value theorem but instead + + + align:start position:0% +intermediate value theorem but instead +of proving this theorem in its full + + align:start position:0% +of proving this theorem in its full + + + align:start position:0% +of proving this theorem in its full +generality let me just give you kind of + + align:start position:0% +generality let me just give you kind of + + + align:start position:0% +generality let me just give you kind of +a representative example + + align:start position:0% + + + + align:start position:0% + +so let's take + + align:start position:0% + + + + align:start position:0% + +f of x equals x to the + + align:start position:0% +f of x equals x to the + + + align:start position:0% +f of x equals x to the + + align:start position:0% + + + align:start position:0% + + align:start position:0% + + + align:start position:0% +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +minus x to the + + align:start position:0% +minus x to the + + + align:start position:0% +minus x to the +20 20 + + align:start position:0% +20 20 + + + align:start position:0% +20 20 +plus + + align:start position:0% +plus + + + align:start position:0% +plus +i don't know what's today + + align:start position:0% +i don't know what's today + + + align:start position:0% +i don't know what's today +i think the 25th or 24th i don't know 10 + + align:start position:0% +i think the 25th or 24th i don't know 10 + + + align:start position:0% +i think the 25th or 24th i don't know 10 + + align:start position:0% + + + align:start position:0% +x + + align:start position:0% + + + + align:start position:0% + +minus + + align:start position:0% +minus + + + align:start position:0% +minus +300. + + align:start position:0% +300. + + + align:start position:0% +300. +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so what's the point + + align:start position:0% + + + + align:start position:0% + +as long as i plug in a big enough x + + align:start position:0% +as long as i plug in a big enough x + + + align:start position:0% +as long as i plug in a big enough x +um + + align:start position:0% +um + + + align:start position:0% +um +i will + + align:start position:0% +i will + + + align:start position:0% +i will +this will swamp everything + + align:start position:0% +this will swamp everything + + + align:start position:0% +this will swamp everything +here + + align:start position:0% +here + + + align:start position:0% +here +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so for example if i stick in + + align:start position:0% +so for example if i stick in + + + align:start position:0% +so for example if i stick in +f of + + align:start position:0% + + + + align:start position:0% + +you know 100 000 + + align:start position:0% +you know 100 000 + + + align:start position:0% +you know 100 000 +i leave it to you to check that this is + + align:start position:0% +i leave it to you to check that this is + + + align:start position:0% +i leave it to you to check that this is +positive right because + + align:start position:0% +positive right because + + + align:start position:0% +positive right because +this will be a hundred thousand to the + + align:start position:0% +this will be a hundred thousand to the + + + align:start position:0% +this will be a hundred thousand to the +2020 minus a hundred thousand to the + + align:start position:0% +2020 minus a hundred thousand to the + + + align:start position:0% +2020 minus a hundred thousand to the + + align:start position:0% + + + align:start position:0% +uh + + align:start position:0% +uh + + + align:start position:0% +uh +or 20 21 + + align:start position:0% +or 20 21 + + + align:start position:0% +or 20 21 +and then plus this which will be + + align:start position:0% +and then plus this which will be + + + align:start position:0% +and then plus this which will be +positive minus 300 this doesn't matter + + align:start position:0% +positive minus 300 this doesn't matter + + + align:start position:0% +positive minus 300 this doesn't matter +so what really matters is this big guy + + align:start position:0% +so what really matters is this big guy + + + align:start position:0% +so what really matters is this big guy +or this guy with the largest + + align:start position:0% +or this guy with the largest + + + align:start position:0% +or this guy with the largest +power will + + align:start position:0% +power will + + + align:start position:0% +power will +swamp all the other ones and eventually + + align:start position:0% +swamp all the other ones and eventually + + + align:start position:0% +swamp all the other ones and eventually +be positive if i stick in a large enough + + align:start position:0% +be positive if i stick in a large enough + + + align:start position:0% +be positive if i stick in a large enough +positive value + + align:start position:0% +positive value + + + align:start position:0% +positive value +and likewise + + align:start position:0% + + + + align:start position:0% + +in fact for this guy + + align:start position:0% +in fact for this guy + + + align:start position:0% +in fact for this guy +if i stick in a negative + + align:start position:0% + + + + align:start position:0% + +value + + align:start position:0% +value + + + align:start position:0% +value +then i get something very big but now + + align:start position:0% +then i get something very big but now + + + align:start position:0% +then i get something very big but now +with the minus sign which will again + + align:start position:0% +with the minus sign which will again + + + align:start position:0% +with the minus sign which will again +swamp all these earlier guys in fact i + + align:start position:0% +swamp all these earlier guys in fact i + + + align:start position:0% +swamp all these earlier guys in fact i +don't have to choose minus a hundred + + align:start position:0% +don't have to choose minus a hundred + + + align:start position:0% +don't have to choose minus a hundred +thousand if i just stick in zero i will + + align:start position:0% +thousand if i just stick in zero i will + + + align:start position:0% +thousand if i just stick in zero i will +get minus 300 which will be negative but + + align:start position:0% +get minus 300 which will be negative but + + + align:start position:0% +get minus 300 which will be negative but +you can check that if i stick in minus + + align:start position:0% +you can check that if i stick in minus + + + align:start position:0% +you can check that if i stick in minus +100 000 this will still be negative + + align:start position:0% + + + + align:start position:0% + +thus by the intermediate value theorem + + align:start position:0% +thus by the intermediate value theorem + + + align:start position:0% +thus by the intermediate value theorem +there exists a c in + + align:start position:0% + + + + align:start position:0% + +100 000 + + align:start position:0% + + + + align:start position:0% + +100 000 + + align:start position:0% + + + + align:start position:0% + +so that + + align:start position:0% + + + + align:start position:0% + +f of c equals 0 right because 0 is + + align:start position:0% +f of c equals 0 right because 0 is + + + align:start position:0% +f of c equals 0 right because 0 is +something in between + + align:start position:0% +something in between + + + align:start position:0% +something in between +f evaluated at these two endpoints + + align:start position:0% +f evaluated at these two endpoints + + + align:start position:0% +f evaluated at these two endpoints +all right + + align:start position:0% +all right + + + align:start position:0% +all right +but again + + align:start position:0% +but again + + + align:start position:0% +but again +you + + align:start position:0% +you + + + align:start position:0% +you +can prove this and the idea is the same + + align:start position:0% +can prove this and the idea is the same + + + align:start position:0% +can prove this and the idea is the same +is that as long as you go far enough uh + + align:start position:0% +is that as long as you go far enough uh + + + align:start position:0% +is that as long as you go far enough uh +out and positive then the polynomial + + align:start position:0% +out and positive then the polynomial + + + align:start position:0% +out and positive then the polynomial +will be + + align:start position:0% +will be + + + align:start position:0% +will be +um + + align:start position:0% +um + + + align:start position:0% +um +positive if the coefficient out of front + + align:start position:0% +positive if the coefficient out of front + + + align:start position:0% +positive if the coefficient out of front +is positive + + align:start position:0% +is positive + + + align:start position:0% +is positive +and if you go far enough out negative + + align:start position:0% +and if you go far enough out negative + + + align:start position:0% +and if you go far enough out negative +then + + align:start position:0% +then + + + align:start position:0% +then +um you'll get something that's uh + + align:start position:0% + + + + align:start position:0% + +that's negative and then you apply the + + align:start position:0% +that's negative and then you apply the + + + align:start position:0% +that's negative and then you apply the +intermediate value theorem to to be able + + align:start position:0% +intermediate value theorem to to be able + + + align:start position:0% +intermediate value theorem to to be able +to + + align:start position:0% +to + + + align:start position:0% +to +find a root + + align:start position:0% +find a root + + + align:start position:0% +find a root +okay + + align:start position:0% +okay + + + align:start position:0% +okay +now of course uh one other thing we did + + align:start position:0% +now of course uh one other thing we did + + + align:start position:0% +now of course uh one other thing we did +with the statement of the mid max + + align:start position:0% +with the statement of the mid max + + + align:start position:0% +with the statement of the mid max +theorem was + + align:start position:0% + + + + align:start position:0% + +you know can we + + align:start position:0% +you know can we + + + align:start position:0% +you know can we +drop + + align:start position:0% +drop + + + align:start position:0% +drop +um any of the assumptions on + + align:start position:0% +um any of the assumptions on + + + align:start position:0% +um any of the assumptions on +you know this theorem + + align:start position:0% +you know this theorem + + + align:start position:0% +you know this theorem +and you know you can see that the + + align:start position:0% +and you know you can see that the + + + align:start position:0% +and you know you can see that the +example is no + + align:start position:0% +example is no + + + align:start position:0% +example is no +so + + align:start position:0% +so + + + align:start position:0% +so +the question is if f + + align:start position:0% +the question is if f + + + align:start position:0% +the question is if f +from a closed and bounded interval + + align:start position:0% + + + + align:start position:0% + +is not + + align:start position:0% + + + + align:start position:0% + +continuous + + align:start position:0% + + + + align:start position:0% + +and let's say + + align:start position:0% +and let's say + + + align:start position:0% +and let's say +f of 0 is less than 0 f of a + + align:start position:0% + + + + align:start position:0% + +if b is bigger than 0 then + + align:start position:0% +if b is bigger than 0 then + + + align:start position:0% +if b is bigger than 0 then +does there exist + + align:start position:0% +does there exist + + + align:start position:0% +does there exist +c + + align:start position:0% + + + + align:start position:0% + +a b such that + + align:start position:0% +a b such that + + + align:start position:0% +a b such that +f c equals zero + + align:start position:0% +f c equals zero + + + align:start position:0% +f c equals zero +okay + + align:start position:0% + + + + align:start position:0% + +let me put that question mark at the end + + align:start position:0% + + + + align:start position:0% + +all right + + align:start position:0% + + + + align:start position:0% + +and it's easy to come up with an example + + align:start position:0% +and it's easy to come up with an example + + + align:start position:0% +and it's easy to come up with an example +of a function + + align:start position:0% +of a function + + + align:start position:0% +of a function +that is not continuous that satisfies + + align:start position:0% +that is not continuous that satisfies + + + align:start position:0% +that is not continuous that satisfies +these conclusions and there does not + + align:start position:0% +these conclusions and there does not + + + align:start position:0% +these conclusions and there does not +exist a point in between so that f of c + + align:start position:0% +exist a point in between so that f of c + + + align:start position:0% +exist a point in between so that f of c +equals zero simplest being + + align:start position:0% +equals zero simplest being + + + align:start position:0% +equals zero simplest being +i'll just draw + + align:start position:0% +i'll just draw + + + align:start position:0% +i'll just draw +a picture let's go from + + align:start position:0% + + + + align:start position:0% + +uh + + align:start position:0% +uh + + + align:start position:0% +uh +minus one + + align:start position:0% +minus one + + + align:start position:0% +minus one +one + + align:start position:0% +one + + + align:start position:0% +one +two okay + + align:start position:0% +two okay + + + align:start position:0% +two okay +so then the function + + align:start position:0% +so then the function + + + align:start position:0% +so then the function +is + + align:start position:0% + + + + align:start position:0% + +f of x equals + + align:start position:0% + + + + align:start position:0% + +x minus 1 and + + align:start position:0% +x minus 1 and + + + align:start position:0% +x minus 1 and +this is for x not equal to + + align:start position:0% +this is for x not equal to + + + align:start position:0% +this is for x not equal to +uh one and + + align:start position:0% +uh one and + + + align:start position:0% +uh one and +you know let's make it uh let's make it + + align:start position:0% +you know let's make it uh let's make it + + + align:start position:0% +you know let's make it uh let's make it +a half there + + align:start position:0% + + + + align:start position:0% + +so this function looks like + + align:start position:0% + + + + align:start position:0% + +half + + align:start position:0% +half + + + align:start position:0% +half +there + + align:start position:0% +there + + + align:start position:0% +there +okay so there's no value there's no c in + + align:start position:0% +okay so there's no value there's no c in + + + align:start position:0% +okay so there's no value there's no c in +between + + align:start position:0% +between + + + align:start position:0% +between +uh + + align:start position:0% +uh + + + align:start position:0% +uh +so + + align:start position:0% + + + + align:start position:0% + +x is between 0 and 2. so you see f of 0 + + align:start position:0% +x is between 0 and 2. so you see f of 0 + + + align:start position:0% +x is between 0 and 2. so you see f of 0 +is equal to -1 that's negative f of 2 is + + align:start position:0% +is equal to -1 that's negative f of 2 is + + + align:start position:0% +is equal to -1 that's negative f of 2 is +equal to 1 it's positive but there + + align:start position:0% +equal to 1 it's positive but there + + + align:start position:0% +equal to 1 it's positive but there +exists no c in between + + align:start position:0% +exists no c in between + + + align:start position:0% +exists no c in between +so that f of c equals 0. okay + + align:start position:0% +so that f of c equals 0. okay + + + align:start position:0% +so that f of c equals 0. okay +so + + align:start position:0% +so + + + align:start position:0% +so +what's the point i'm making + + align:start position:0% +what's the point i'm making + + + align:start position:0% +what's the point i'm making +we really do need this hypothesis + + align:start position:0% +we really do need this hypothesis + + + align:start position:0% +we really do need this hypothesis +that the function is continuous for this + + align:start position:0% +that the function is continuous for this + + + align:start position:0% +that the function is continuous for this +theorem to be true + + align:start position:0% +theorem to be true + + + align:start position:0% +theorem to be true +okay if you drop that hypothesis then + + align:start position:0% +okay if you drop that hypothesis then + + + align:start position:0% +okay if you drop that hypothesis then +the theorem is no longer true + + align:start position:0% +the theorem is no longer true + + + align:start position:0% +the theorem is no longer true +okay + + align:start position:0% + + + + align:start position:0% + +okay so um + + align:start position:0% +okay so um + + + align:start position:0% +okay so um +now we're going to move on to a new + + align:start position:0% +now we're going to move on to a new + + + align:start position:0% +now we're going to move on to a new +concept + + align:start position:0% + + + + align:start position:0% + +called uniform continuity + + align:start position:0% + + + + align:start position:0% + +and before i do this i'm going to bring + + align:start position:0% +and before i do this i'm going to bring + + + align:start position:0% +and before i do this i'm going to bring +up or i'm going to rewrite + + align:start position:0% +up or i'm going to rewrite + + + align:start position:0% +up or i'm going to rewrite +the definition of continuity + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +this is a old definition but i want to + + align:start position:0% +this is a old definition but i want to + + + align:start position:0% +this is a old definition but i want to +highlight a specific + + align:start position:0% +highlight a specific + + + align:start position:0% +highlight a specific +aspect of it so this is uh me writing + + align:start position:0% +aspect of it so this is uh me writing + + + align:start position:0% +aspect of it so this is uh me writing +the definition of a continuous function + + align:start position:0% +the definition of a continuous function + + + align:start position:0% +the definition of a continuous function +again + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% + + + + align:start position:0% + +a function f + + align:start position:0% +a function f + + + align:start position:0% +a function f +from a set s to r + + align:start position:0% +from a set s to r + + + align:start position:0% +from a set s to r +is + + align:start position:0% + + + + align:start position:0% + +continuous + + align:start position:0% +continuous + + + align:start position:0% +continuous +so we said that means it's continuous at + + align:start position:0% +so we said that means it's continuous at + + + align:start position:0% +so we said that means it's continuous at +every point + + align:start position:0% +every point + + + align:start position:0% +every point +meaning + + align:start position:0% +meaning + + + align:start position:0% +meaning +if + + align:start position:0% +if + + + align:start position:0% +if +for all c and s + + align:start position:0% +for all c and s + + + align:start position:0% +for all c and s +it's continuous at c which means for all + + align:start position:0% +it's continuous at c which means for all + + + align:start position:0% +it's continuous at c which means for all +epsilon positive there exists a delta + + align:start position:0% +epsilon positive there exists a delta + + + align:start position:0% +epsilon positive there exists a delta +now this delta + + align:start position:0% +now this delta + + + align:start position:0% +now this delta +and + + align:start position:0% +and + + + align:start position:0% +and +you know we saw this in examples uh + + align:start position:0% +you know we saw this in examples uh + + + align:start position:0% +you know we saw this in examples uh +that we did proving continuity + + align:start position:0% +that we did proving continuity + + + align:start position:0% +that we did proving continuity +this usually depends on + + align:start position:0% +this usually depends on + + + align:start position:0% +this usually depends on +epsilon and c the point + + align:start position:0% +epsilon and c the point + + + align:start position:0% +epsilon and c the point +where i'm looking at + + align:start position:0% + + + + align:start position:0% + +such that + + align:start position:0% + + + + align:start position:0% + +for all x and s + + align:start position:0% +for all x and s + + + align:start position:0% +for all x and s +x minus c less than delta implies that + + align:start position:0% +x minus c less than delta implies that + + + align:start position:0% +x minus c less than delta implies that +f of x minus f of c + + align:start position:0% +f of x minus f of c + + + align:start position:0% +f of x minus f of c +is less than epsilon + + align:start position:0% +is less than epsilon + + + align:start position:0% +is less than epsilon +okay + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +just to + + align:start position:0% +just to + + + align:start position:0% +just to +so this is again a bit of review but i + + align:start position:0% +so this is again a bit of review but i + + + align:start position:0% +so this is again a bit of review but i +just want to show you that in general + + align:start position:0% +just want to show you that in general + + + align:start position:0% +just want to show you that in general +you know when we + + align:start position:0% +you know when we + + + align:start position:0% +you know when we +verify that a function is continuous on + + align:start position:0% +verify that a function is continuous on + + + align:start position:0% +verify that a function is continuous on +a set we have to show it's continuous at + + align:start position:0% +a set we have to show it's continuous at + + + align:start position:0% +a set we have to show it's continuous at +every point in the set and that means + + align:start position:0% +every point in the set and that means + + + align:start position:0% +every point in the set and that means +for every epsilon there exists a delta + + align:start position:0% +for every epsilon there exists a delta + + + align:start position:0% +for every epsilon there exists a delta +but this delta can depend on usually it + + align:start position:0% +but this delta can depend on usually it + + + align:start position:0% +but this delta can depend on usually it +depends on epsilon but it can also + + align:start position:0% +depends on epsilon but it can also + + + align:start position:0% +depends on epsilon but it can also +depend on the point c which is where + + align:start position:0% +depend on the point c which is where + + + align:start position:0% +depend on the point c which is where +we're checking continuity at okay + + align:start position:0% +we're checking continuity at okay + + + align:start position:0% +we're checking continuity at okay +so + + align:start position:0% +so + + + align:start position:0% +so +for simple example let's take + + align:start position:0% +for simple example let's take + + + align:start position:0% +for simple example let's take +f of x equals 1 over x + + align:start position:0% + + + + align:start position:0% + +on the interval 0 1 open interval 0 1. + + align:start position:0% +on the interval 0 1 open interval 0 1. + + + align:start position:0% +on the interval 0 1 open interval 0 1. +okay so i claim + + align:start position:0% +okay so i claim + + + align:start position:0% +okay so i claim +f of x + + align:start position:0% + + + + align:start position:0% + +equals 1 over x is continuous + + align:start position:0% +equals 1 over x is continuous + + + align:start position:0% +equals 1 over x is continuous +so proof + + align:start position:0% +so proof + + + align:start position:0% +so proof +we have to show that for every c + + align:start position:0% +we have to show that for every c + + + align:start position:0% +we have to show that for every c +in 0 1 for all epsilon there exists that + + align:start position:0% +in 0 1 for all epsilon there exists that + + + align:start position:0% +in 0 1 for all epsilon there exists that +so let's see + + align:start position:0% + + + + align:start position:0% + +b and 0 1. + + align:start position:0% + + + + align:start position:0% + +let + + align:start position:0% +let + + + align:start position:0% +let +epsilon be positive + + align:start position:0% + + + + align:start position:0% + +now choose + + align:start position:0% + + + + align:start position:0% + +again i mean i'm not since this is kind + + align:start position:0% +again i mean i'm not since this is kind + + + align:start position:0% +again i mean i'm not since this is kind +of review i'm not going to go through + + align:start position:0% +of review i'm not going to go through + + + align:start position:0% +of review i'm not going to go through +the process of of really the thinking + + align:start position:0% +the process of of really the thinking + + + align:start position:0% +the process of of really the thinking +behind choosing this + + align:start position:0% +behind choosing this + + + align:start position:0% +behind choosing this +this delta i mean there's you know + + align:start position:0% +this delta i mean there's you know + + + align:start position:0% +this delta i mean there's you know +calculations you do off to the side to + + align:start position:0% +calculations you do off to the side to + + + align:start position:0% +calculations you do off to the side to +try and get this delta but let's choose + + align:start position:0% +try and get this delta but let's choose + + + align:start position:0% +try and get this delta but let's choose +delta to be + + align:start position:0% +delta to be + + + align:start position:0% +delta to be +the minimum of + + align:start position:0% +the minimum of + + + align:start position:0% +the minimum of +c over 2 + + align:start position:0% +c over 2 + + + align:start position:0% +c over 2 +and + + align:start position:0% +and + + + align:start position:0% +and +c squared over 2 + + align:start position:0% +c squared over 2 + + + align:start position:0% +c squared over 2 +times epsilon + + align:start position:0% +times epsilon + + + align:start position:0% +times epsilon +so what you notice + + align:start position:0% +so what you notice + + + align:start position:0% +so what you notice +what i want to again emphasize is this + + align:start position:0% +what i want to again emphasize is this + + + align:start position:0% +what i want to again emphasize is this +delta depends on c the point we're + + align:start position:0% +delta depends on c the point we're + + + align:start position:0% +delta depends on c the point we're +looking at and epsilon okay + + align:start position:0% +looking at and epsilon okay + + + align:start position:0% +looking at and epsilon okay +so i claim this delta works + + align:start position:0% + + + + align:start position:0% + +suppose x is in + + align:start position:0% +suppose x is in + + + align:start position:0% +suppose x is in +0 1 and x minus c + + align:start position:0% +0 1 and x minus c + + + align:start position:0% +0 1 and x minus c +is less than delta + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +then + + align:start position:0% + + + + align:start position:0% + +absolute value of x this is equal to the + + align:start position:0% +absolute value of x this is equal to the + + + align:start position:0% +absolute value of x this is equal to the +f + + align:start position:0% +f + + + align:start position:0% +f +this is + + align:start position:0% +this is + + + align:start position:0% +this is +by the triangle inequality + + align:start position:0% + + + + align:start position:0% + +so let me write it this way + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% +um + + + align:start position:0% +um +c + + align:start position:0% +c + + + align:start position:0% +c +absolute value + + align:start position:0% +absolute value + + + align:start position:0% +absolute value +is equal to + + align:start position:0% +is equal to + + + align:start position:0% +is equal to +c minus x plus x which is less than or + + align:start position:0% +c minus x plus x which is less than or + + + align:start position:0% +c minus x plus x which is less than or +equal to + + align:start position:0% +equal to + + + align:start position:0% +equal to +c minus x + + align:start position:0% +c minus x + + + align:start position:0% +c minus x +plus x + + align:start position:0% +plus x + + + align:start position:0% +plus x +which is less than delta + + align:start position:0% + + + + align:start position:0% + +which is less than or equal to the + + align:start position:0% +which is less than or equal to the + + + align:start position:0% +which is less than or equal to the +minimum of these two so it's certainly + + align:start position:0% +minimum of these two so it's certainly + + + align:start position:0% +minimum of these two so it's certainly +mess less than or equal to c over two + + align:start position:0% + + + + align:start position:0% + +plus x and now you know c and uh + + align:start position:0% +plus x and now you know c and uh + + + align:start position:0% +plus x and now you know c and uh +x these are in zero one so they're all + + align:start position:0% +x these are in zero one so they're all + + + align:start position:0% +x these are in zero one so they're all +positive + + align:start position:0% + + + + align:start position:0% + +and therefore i get that + + align:start position:0% + + + + align:start position:0% + +let's go to the next board + + align:start position:0% +let's go to the next board + + + align:start position:0% +let's go to the next board +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +so if i subtract the c over to the other + + align:start position:0% +so if i subtract the c over to the other + + + align:start position:0% +so if i subtract the c over to the other +the c over 2 over to the other side i + + align:start position:0% +the c over 2 over to the other side i + + + align:start position:0% +the c over 2 over to the other side i +get that + + align:start position:0% +get that + + + align:start position:0% +get that +c over 2 is less than + + align:start position:0% +c over 2 is less than + + + align:start position:0% +c over 2 is less than +x all right so this is as long as x is + + align:start position:0% +x all right so this is as long as x is + + + align:start position:0% +x all right so this is as long as x is +in 0 1 and x minus c is less than delta + + align:start position:0% +in 0 1 and x minus c is less than delta + + + align:start position:0% +in 0 1 and x minus c is less than delta +okay this should not be a shock all + + align:start position:0% +okay this should not be a shock all + + + align:start position:0% +okay this should not be a shock all +right + + align:start position:0% +right + + + align:start position:0% +right +here's 0 + + align:start position:0% +here's 0 + + + align:start position:0% +here's 0 + + align:start position:0% + + + align:start position:0% +c + + align:start position:0% +c + + + align:start position:0% +c +c over 2 + + align:start position:0% +c over 2 + + + align:start position:0% +c over 2 +3 c over 2. + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and so if x is in this interval it's + + align:start position:0% +and so if x is in this interval it's + + + align:start position:0% +and so if x is in this interval it's +certainly bounded away by c over two + + align:start position:0% +certainly bounded away by c over two + + + align:start position:0% +certainly bounded away by c over two +okay + + align:start position:0% +okay + + + align:start position:0% +okay +um or if x is in here then x is + + align:start position:0% +um or if x is in here then x is + + + align:start position:0% +um or if x is in here then x is +certainly bigger than c over two + + align:start position:0% + + + + align:start position:0% + +all right and now we look at + + align:start position:0% + + + + align:start position:0% + +f of x minus f of c + + align:start position:0% +f of x minus f of c + + + align:start position:0% +f of x minus f of c +this is equal to 1 over x minus 1 over c + + align:start position:0% +this is equal to 1 over x minus 1 over c + + + align:start position:0% +this is equal to 1 over x minus 1 over c +equals + + align:start position:0% + + + + align:start position:0% + +c minus x over x times c + + align:start position:0% +c minus x over x times c + + + align:start position:0% +c minus x over x times c +which is less than delta over x times c + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% +and + + + align:start position:0% +and +because this is a + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and now x is less than x is bigger than + + align:start position:0% +and now x is less than x is bigger than + + + align:start position:0% +and now x is less than x is bigger than +c over 2 so if i take 1 over that + + align:start position:0% +c over 2 so if i take 1 over that + + + align:start position:0% +c over 2 so if i take 1 over that +i get + + align:start position:0% +i get + + + align:start position:0% +i get +1 over x is less than 2 over c so this + + align:start position:0% +1 over x is less than 2 over c so this + + + align:start position:0% +1 over x is less than 2 over c so this +is less than or equal to 2 delta + + align:start position:0% +is less than or equal to 2 delta + + + align:start position:0% +is less than or equal to 2 delta +over c squared and delta is the minimum + + align:start position:0% +over c squared and delta is the minimum + + + align:start position:0% +over c squared and delta is the minimum +of now c over 2 and c squared over 2 + + align:start position:0% +of now c over 2 and c squared over 2 + + + align:start position:0% +of now c over 2 and c squared over 2 +times epsilon + + align:start position:0% +times epsilon + + + align:start position:0% +times epsilon +so this is less than or equal to 2 over + + align:start position:0% +so this is less than or equal to 2 over + + + align:start position:0% +so this is less than or equal to 2 over +c squared times c squared over two + + align:start position:0% +c squared times c squared over two + + + align:start position:0% +c squared times c squared over two +epsilon equals epsilon okay + + align:start position:0% +epsilon equals epsilon okay + + + align:start position:0% +epsilon equals epsilon okay +so i just went through the proof of + + align:start position:0% +so i just went through the proof of + + + align:start position:0% +so i just went through the proof of +continuity for one over x which uh + + align:start position:0% +continuity for one over x which uh + + + align:start position:0% +continuity for one over x which uh +you know using + + align:start position:0% +you know using + + + align:start position:0% +you know using +better machinery we could have proven + + align:start position:0% +better machinery we could have proven + + + align:start position:0% +better machinery we could have proven +but uh + + align:start position:0% +but uh + + + align:start position:0% +but uh +i did this to to highlight this point + + align:start position:0% + + + + align:start position:0% + +that's showing + + align:start position:0% +that's showing + + + align:start position:0% +that's showing +continuity of one over x on zero one + + align:start position:0% +continuity of one over x on zero one + + + align:start position:0% +continuity of one over x on zero one +that in showing that you know + + align:start position:0% +that in showing that you know + + + align:start position:0% +that in showing that you know +this delta that you are choosing depends + + align:start position:0% +this delta that you are choosing depends + + + align:start position:0% +this delta that you are choosing depends +kind of on the point you're looking at + + align:start position:0% +kind of on the point you're looking at + + + align:start position:0% +kind of on the point you're looking at +all right so + + align:start position:0% + + + + align:start position:0% + +now i want to make a + + align:start position:0% + + + + align:start position:0% + +so you know what the definition of + + align:start position:0% +so you know what the definition of + + + align:start position:0% +so you know what the definition of +continuity says is for all c + + align:start position:0% +continuity says is for all c + + + align:start position:0% +continuity says is for all c +for all epsilon you can find a delta + + align:start position:0% +for all epsilon you can find a delta + + + align:start position:0% +for all epsilon you can find a delta +uh depending on epsilon and c + + align:start position:0% +uh depending on epsilon and c + + + align:start position:0% +uh depending on epsilon and c +now uniform continuity + + align:start position:0% +now uniform continuity + + + align:start position:0% +now uniform continuity +removes that necessity of delta + + align:start position:0% +removes that necessity of delta + + + align:start position:0% +removes that necessity of delta +depending on c + + align:start position:0% +depending on c + + + align:start position:0% +depending on c +okay and i'm going to make a + + align:start position:0% +okay and i'm going to make a + + + align:start position:0% +okay and i'm going to make a +possibly bad analogy in just a minute + + align:start position:0% +possibly bad analogy in just a minute + + + align:start position:0% +possibly bad analogy in just a minute +but first let me write down the + + align:start position:0% +but first let me write down the + + + align:start position:0% +but first let me write down the +definition of uniform continuity + + align:start position:0% + + + + align:start position:0% + +let s be a subset of r + + align:start position:0% +let s be a subset of r + + + align:start position:0% +let s be a subset of r +f going from s to r + + align:start position:0% + + + + align:start position:0% + +we say f + + align:start position:0% +we say f + + + align:start position:0% +we say f +is + + align:start position:0% + + + + align:start position:0% + +uniformly + + align:start position:0% + + + + align:start position:0% + +continuous + + align:start position:0% + + + + align:start position:0% + +on s + + align:start position:0% +on s + + + align:start position:0% +on s +if + + align:start position:0% + + + + align:start position:0% + +we're all epsilon positive + + align:start position:0% +we're all epsilon positive + + + align:start position:0% +we're all epsilon positive +there exists a delta depending only on + + align:start position:0% +there exists a delta depending only on + + + align:start position:0% +there exists a delta depending only on +epsilon + + align:start position:0% + + + + align:start position:0% + +such that + + align:start position:0% +such that + + + align:start position:0% +such that +for all xc and s + + align:start position:0% +for all xc and s + + + align:start position:0% +for all xc and s +with x minus c less than delta + + align:start position:0% +with x minus c less than delta + + + align:start position:0% +with x minus c less than delta +we get that f of x + + align:start position:0% +we get that f of x + + + align:start position:0% +we get that f of x +minus f of c + + align:start position:0% +minus f of c + + + align:start position:0% +minus f of c +is less than epsilon + + align:start position:0% +is less than epsilon + + + align:start position:0% +is less than epsilon +okay so + + align:start position:0% + + + + align:start position:0% + +you know a function being continuous + + align:start position:0% +you know a function being continuous + + + align:start position:0% +you know a function being continuous +means that for all epsilon you can find + + align:start position:0% +means that for all epsilon you can find + + + align:start position:0% +means that for all epsilon you can find +a delta depending on one of these points + + align:start position:0% +a delta depending on one of these points + + + align:start position:0% +a delta depending on one of these points +depending on c so that if i have this + + align:start position:0% +depending on c so that if i have this + + + align:start position:0% +depending on c so that if i have this +then i have this + + align:start position:0% +then i have this + + + align:start position:0% +then i have this +uniform continuity says you can find a + + align:start position:0% +uniform continuity says you can find a + + + align:start position:0% +uniform continuity says you can find a +delta + + align:start position:0% +delta + + + align:start position:0% +delta +that works across the board okay um + + align:start position:0% + + + + align:start position:0% + +so i'm gonna make a try and make a an + + align:start position:0% +so i'm gonna make a try and make a an + + + align:start position:0% +so i'm gonna make a try and make a an +analogy that hopefully i don't have to + + align:start position:0% +analogy that hopefully i don't have to + + + align:start position:0% +analogy that hopefully i don't have to +cut out of this lecture + + align:start position:0% +cut out of this lecture + + + align:start position:0% +cut out of this lecture +um + + align:start position:0% +um + + + align:start position:0% +um +but it's a bit like this + + align:start position:0% +but it's a bit like this + + + align:start position:0% +but it's a bit like this +let's take a trip down memory lane + + align:start position:0% +let's take a trip down memory lane + + + align:start position:0% +let's take a trip down memory lane +and imagine being at a party + + align:start position:0% + + + + align:start position:0% + +so you know everybody's in a party and + + align:start position:0% +so you know everybody's in a party and + + + align:start position:0% +so you know everybody's in a party and +let's + + align:start position:0% +let's + + + align:start position:0% +let's +say that everybody can hear + + align:start position:0% +say that everybody can hear + + + align:start position:0% +say that everybody can hear +their ears work just about the same + + align:start position:0% +their ears work just about the same + + + align:start position:0% +their ears work just about the same +and the goal is you know to try and + + align:start position:0% +and the goal is you know to try and + + + align:start position:0% +and the goal is you know to try and +understand each other's conversations + + align:start position:0% +understand each other's conversations + + + align:start position:0% +understand each other's conversations +try try and hear each other's + + align:start position:0% +try try and hear each other's + + + align:start position:0% +try try and hear each other's +conversations + + align:start position:0% +conversations + + + align:start position:0% +conversations +now in order for + + align:start position:0% +now in order for + + + align:start position:0% +now in order for +um + + align:start position:0% +um + + + align:start position:0% +um +you know + + align:start position:0% +you know + + + align:start position:0% +you know +me to hear this person's conversation + + align:start position:0% +me to hear this person's conversation + + + align:start position:0% +me to hear this person's conversation +depending on how loud they talk i have + + align:start position:0% +depending on how loud they talk i have + + + align:start position:0% +depending on how loud they talk i have +to be + + align:start position:0% +to be + + + align:start position:0% +to be +close enough to be able to hear them + + align:start position:0% +close enough to be able to hear them + + + align:start position:0% +close enough to be able to hear them +you know and this changes from person to + + align:start position:0% +you know and this changes from person to + + + align:start position:0% +you know and this changes from person to +person in the room maybe i have to i can + + align:start position:0% +person in the room maybe i have to i can + + + align:start position:0% +person in the room maybe i have to i can +stand a foot away from + + align:start position:0% +stand a foot away from + + + align:start position:0% +stand a foot away from +this person over here maybe this person + + align:start position:0% +this person over here maybe this person + + + align:start position:0% +this person over here maybe this person +over here is a + + align:start position:0% +over here is a + + + align:start position:0% +over here is a +low talker and i have to be almost up in + + align:start position:0% +low talker and i have to be almost up in + + + align:start position:0% +low talker and i have to be almost up in +their face to be able to hear them maybe + + align:start position:0% +their face to be able to hear them maybe + + + align:start position:0% +their face to be able to hear them maybe +that person just whispers and i have to + + align:start position:0% +that person just whispers and i have to + + + align:start position:0% +that person just whispers and i have to +be almost nose to nose to be able to + + align:start position:0% +be almost nose to nose to be able to + + + align:start position:0% +be almost nose to nose to be able to +hear them you know that's a bit like a + + align:start position:0% +hear them you know that's a bit like a + + + align:start position:0% +hear them you know that's a bit like a +function being + + align:start position:0% +function being + + + align:start position:0% +function being +continuous okay + + align:start position:0% +continuous okay + + + align:start position:0% +continuous okay +you know + + align:start position:0% +you know + + + align:start position:0% +you know +the + + align:start position:0% +the + + + align:start position:0% +the +threshold of hearing + + align:start position:0% +threshold of hearing + + + align:start position:0% +threshold of hearing +what they're saying is the epsilon and i + + align:start position:0% +what they're saying is the epsilon and i + + + align:start position:0% +what they're saying is the epsilon and i +have to change my delta depending on + + align:start position:0% +have to change my delta depending on + + + align:start position:0% +have to change my delta depending on +what point i'm at so that i can hear + + align:start position:0% +what point i'm at so that i can hear + + + align:start position:0% +what point i'm at so that i can hear +them + + align:start position:0% +them + + + align:start position:0% +them +now uniform continuity + + align:start position:0% +now uniform continuity + + + align:start position:0% +now uniform continuity +is kind of like + + align:start position:0% +is kind of like + + + align:start position:0% +is kind of like +everybody's um + + align:start position:0% + + + + align:start position:0% + +more or less speaking around the same uh + + align:start position:0% +more or less speaking around the same uh + + + align:start position:0% +more or less speaking around the same uh +level + + align:start position:0% +level + + + align:start position:0% +level +speaking at the same loudness all right + + align:start position:0% +speaking at the same loudness all right + + + align:start position:0% +speaking at the same loudness all right +so i just can be within say one foot of + + align:start position:0% +so i just can be within say one foot of + + + align:start position:0% +so i just can be within say one foot of +everybody and be able to understand them + + align:start position:0% +everybody and be able to understand them + + + align:start position:0% +everybody and be able to understand them +i go to this person if i'm within one + + align:start position:0% +i go to this person if i'm within one + + + align:start position:0% +i go to this person if i'm within one +foot i can hear them well + + align:start position:0% +foot i can hear them well + + + align:start position:0% +foot i can hear them well +if i go to this person i hear and + + align:start position:0% +if i go to this person i hear and + + + align:start position:0% +if i go to this person i hear and +within one foot i can hear them well and + + align:start position:0% +within one foot i can hear them well and + + + align:start position:0% +within one foot i can hear them well and +and so on all right so that's + + align:start position:0% +and so on all right so that's + + + align:start position:0% +and so on all right so that's +kind of the difference between you know + + align:start position:0% +kind of the difference between you know + + + align:start position:0% +kind of the difference between you know +or at least a loose analogy of the + + align:start position:0% +or at least a loose analogy of the + + + align:start position:0% +or at least a loose analogy of the +difference between continuity and + + align:start position:0% +difference between continuity and + + + align:start position:0% +difference between continuity and +uniform continuity + + align:start position:0% +uniform continuity + + + align:start position:0% +uniform continuity +all right um + + align:start position:0% + + + + align:start position:0% + +so this is a + + align:start position:0% +so this is a + + + align:start position:0% +so this is a +you know + + align:start position:0% +you know + + + align:start position:0% +you know +reasonably interesting definition so we + + align:start position:0% +reasonably interesting definition so we + + + align:start position:0% +reasonably interesting definition so we +should see examples and negate it + + align:start position:0% + + + + align:start position:0% + +um first off + + align:start position:0% +um first off + + + align:start position:0% +um first off +you know i + + align:start position:0% +you know i + + + align:start position:0% +you know i +you should be able to convince yourself + + align:start position:0% +you should be able to convince yourself + + + align:start position:0% +you should be able to convince yourself +that a function that's uniformly + + align:start position:0% +that a function that's uniformly + + + align:start position:0% +that a function that's uniformly +continuous is actually continuous i'm + + align:start position:0% +continuous is actually continuous i'm + + + align:start position:0% +continuous is actually continuous i'm +not going to write that the proof of + + align:start position:0% +not going to write that the proof of + + + align:start position:0% +not going to write that the proof of +that down it follows essentially + + align:start position:0% +that down it follows essentially + + + align:start position:0% +that down it follows essentially +straight from the definition + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% +um + + + align:start position:0% +um +but let's look at uh + + align:start position:0% + + + + align:start position:0% + +let's look at a function which is + + align:start position:0% +let's look at a function which is + + + align:start position:0% +let's look at a function which is +um + + align:start position:0% +um + + + align:start position:0% +um +uniformly consent continuous so + + align:start position:0% +uniformly consent continuous so + + + align:start position:0% +uniformly consent continuous so +the function f of x + + align:start position:0% +the function f of x + + + align:start position:0% +the function f of x +equals x squared + + align:start position:0% +equals x squared + + + align:start position:0% +equals x squared +on the interval 0 1. + + align:start position:0% + + + + align:start position:0% + +is uniformly continuous + + align:start position:0% +is uniformly continuous + + + align:start position:0% +is uniformly continuous +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so what's the proof + + align:start position:0% +so what's the proof + + + align:start position:0% +so what's the proof +i want you to notice i'm going to use + + align:start position:0% +i want you to notice i'm going to use + + + align:start position:0% +i want you to notice i'm going to use +kind of in a + + align:start position:0% +kind of in a + + + align:start position:0% +kind of in a +very + + align:start position:0% +very + + + align:start position:0% +very +essential way that we're on this closed + + align:start position:0% +essential way that we're on this closed + + + align:start position:0% +essential way that we're on this closed +and bounded interval + + align:start position:0% + + + + align:start position:0% + +so we need to show that for every + + align:start position:0% +so we need to show that for every + + + align:start position:0% +so we need to show that for every +epsilon there exists a delta + + align:start position:0% +epsilon there exists a delta + + + align:start position:0% +epsilon there exists a delta +so that no matter what two points + + align:start position:0% + + + + align:start position:0% + +so if you'd like here's a picture that + + align:start position:0% +so if you'd like here's a picture that + + + align:start position:0% +so if you'd like here's a picture that +goes + + align:start position:0% +goes + + + align:start position:0% +goes +along with this + + align:start position:0% + + + + align:start position:0% + +so that if i look at + + align:start position:0% +so that if i look at + + + align:start position:0% +so that if i look at +any two points that are close to each + + align:start position:0% +any two points that are close to each + + + align:start position:0% +any two points that are close to each +other less than delta + + align:start position:0% +other less than delta + + + align:start position:0% +other less than delta +their + + align:start position:0% +their + + + align:start position:0% +their +function's value + + align:start position:0% +function's value + + + align:start position:0% +function's value +is + + align:start position:0% + + + + align:start position:0% + +within epsilon and so let's say i'm on + + align:start position:0% +within epsilon and so let's say i'm on + + + align:start position:0% +within epsilon and so let's say i'm on +interval a b but not just this point i + + align:start position:0% +interval a b but not just this point i + + + align:start position:0% +interval a b but not just this point i +could go over here to two other + + align:start position:0% +could go over here to two other + + + align:start position:0% +could go over here to two other +points that are within delta of each + + align:start position:0% +points that are within delta of each + + + align:start position:0% +points that are within delta of each +other and if i look at + + align:start position:0% +other and if i look at + + + align:start position:0% +other and if i look at +the function evaluated + + align:start position:0% +the function evaluated + + + align:start position:0% +the function evaluated +at the two points + + align:start position:0% +at the two points + + + align:start position:0% +at the two points +and + + align:start position:0% + + + + align:start position:0% + +then the difference between these two + + align:start position:0% +then the difference between these two + + + align:start position:0% +then the difference between these two +guys is also less than epsilon + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so i can move + + align:start position:0% +so i can move + + + align:start position:0% +so i can move +through the party and as long as i'm + + align:start position:0% +through the party and as long as i'm + + + align:start position:0% +through the party and as long as i'm +close enough + + align:start position:0% +close enough + + + align:start position:0% +close enough +within you know a uniform distance to + + align:start position:0% +within you know a uniform distance to + + + align:start position:0% +within you know a uniform distance to +somebody i can i can hear them just fine + + align:start position:0% +somebody i can i can hear them just fine + + + align:start position:0% +somebody i can i can hear them just fine +all right so + + align:start position:0% +all right so + + + align:start position:0% +all right so +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +what a nice trip down memory lane when + + align:start position:0% +what a nice trip down memory lane when + + + align:start position:0% +what a nice trip down memory lane when +we could be around other people um + + align:start position:0% +we could be around other people um + + + align:start position:0% +we could be around other people um +so let's show this function is uniformly + + align:start position:0% +so let's show this function is uniformly + + + align:start position:0% +so let's show this function is uniformly +continuous let epsilon be positive + + align:start position:0% + + + + align:start position:0% + +choose delta to be + + align:start position:0% + + + + align:start position:0% + +epsilon over 2. + + align:start position:0% +epsilon over 2. + + + align:start position:0% +epsilon over 2. +now you see this delta just depends on + + align:start position:0% +now you see this delta just depends on + + + align:start position:0% +now you see this delta just depends on +epsilon + + align:start position:0% +epsilon + + + align:start position:0% +epsilon +okay + + align:start position:0% + + + + align:start position:0% + +then if + + align:start position:0% + + + + align:start position:0% + +x and c are in 0 1 + + align:start position:0% +x and c are in 0 1 + + + align:start position:0% +x and c are in 0 1 +and + + align:start position:0% +and + + + align:start position:0% +and +x minus c is less than delta + + align:start position:0% +x minus c is less than delta + + + align:start position:0% +x minus c is less than delta +then + + align:start position:0% +then + + + align:start position:0% +then +if i compute + + align:start position:0% +if i compute + + + align:start position:0% +if i compute +the difference x squared minus c squared + + align:start position:0% +the difference x squared minus c squared + + + align:start position:0% +the difference x squared minus c squared +this is + + align:start position:0% +this is + + + align:start position:0% +this is +i can write as x plus c times x minus c + + align:start position:0% + + + + align:start position:0% + +and now i use the triangle inequality + + align:start position:0% +and now i use the triangle inequality + + + align:start position:0% +and now i use the triangle inequality +this is less than or equal to + + align:start position:0% + + + + align:start position:0% + +x minus c + + align:start position:0% +x minus c + + + align:start position:0% +x minus c +now these guys are in zero one so their + + align:start position:0% +now these guys are in zero one so their + + + align:start position:0% +now these guys are in zero one so their +absolute value is always bounded by one + + align:start position:0% +absolute value is always bounded by one + + + align:start position:0% +absolute value is always bounded by one +so this is less than or equal to one + + align:start position:0% +so this is less than or equal to one + + + align:start position:0% +so this is less than or equal to one +plus one + + align:start position:0% +plus one + + + align:start position:0% +plus one +and then x minus c is bounded by delta + + align:start position:0% +and then x minus c is bounded by delta + + + align:start position:0% +and then x minus c is bounded by delta +which equals two times delta and delta + + align:start position:0% +which equals two times delta and delta + + + align:start position:0% +which equals two times delta and delta +is chosen to be epsilon over two so i + + align:start position:0% +is chosen to be epsilon over two so i + + + align:start position:0% +is chosen to be epsilon over two so i +get epsilon + + align:start position:0% +get epsilon + + + align:start position:0% +get epsilon +all right now again how would you choose + + align:start position:0% +all right now again how would you choose + + + align:start position:0% +all right now again how would you choose +delta so it looks like i just chose this + + align:start position:0% +delta so it looks like i just chose this + + + align:start position:0% +delta so it looks like i just chose this +delta out of nowhere in practice how do + + align:start position:0% +delta out of nowhere in practice how do + + + align:start position:0% +delta out of nowhere in practice how do +you choose delta + + align:start position:0% +you choose delta + + + align:start position:0% +you choose delta +this is the computation you do you take + + align:start position:0% +this is the computation you do you take + + + align:start position:0% +this is the computation you do you take +x squared minus c squared split it + + align:start position:0% +x squared minus c squared split it + + + align:start position:0% +x squared minus c squared split it +you have this + + align:start position:0% +you have this + + + align:start position:0% +you have this +you can estimate with what you know + + align:start position:0% +you can estimate with what you know + + + align:start position:0% +you can estimate with what you know +above by + + align:start position:0% +above by + + + align:start position:0% +above by +2 here times delta + + align:start position:0% +2 here times delta + + + align:start position:0% +2 here times delta +so how do you choose delta so that two + + align:start position:0% +so how do you choose delta so that two + + + align:start position:0% +so how do you choose delta so that two +times delta is + + align:start position:0% +times delta is + + + align:start position:0% +times delta is +say equal to epsilon you choose delta to + + align:start position:0% +say equal to epsilon you choose delta to + + + align:start position:0% +say equal to epsilon you choose delta to +be epsilon over two + + align:start position:0% +be epsilon over two + + + align:start position:0% +be epsilon over two +okay + + align:start position:0% + + + + align:start position:0% + +all right so um + + align:start position:0% + + + + align:start position:0% + +let's negate this definition and then + + align:start position:0% +let's negate this definition and then + + + align:start position:0% +let's negate this definition and then +look at one over x once again + + align:start position:0% +look at one over x once again + + + align:start position:0% +look at one over x once again +and check to see if it's uniformly + + align:start position:0% +and check to see if it's uniformly + + + align:start position:0% +and check to see if it's uniformly +continuous we'll show it's not + + align:start position:0% +continuous we'll show it's not + + + align:start position:0% +continuous we'll show it's not +so the negation + + align:start position:0% +so the negation + + + align:start position:0% +so the negation +f from s to r + + align:start position:0% + + + + align:start position:0% + +is not uniformly + + align:start position:0% + + + + align:start position:0% + +continuous + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% + + + + align:start position:0% + +i saw a little bit of the new borat + + align:start position:0% +i saw a little bit of the new borat + + + align:start position:0% +i saw a little bit of the new borat +movie that came out so i almost wanted + + align:start position:0% +movie that came out so i almost wanted + + + align:start position:0% +movie that came out so i almost wanted +to say + + align:start position:0% +to say + + + align:start position:0% +to say +f is uniformly continuous not but i + + align:start position:0% +f is uniformly continuous not but i + + + align:start position:0% +f is uniformly continuous not but i +didn't + + align:start position:0% +didn't + + + align:start position:0% +didn't +it's not uniformly continuous + + align:start position:0% +it's not uniformly continuous + + + align:start position:0% +it's not uniformly continuous +if and now you negate the rest of the + + align:start position:0% +if and now you negate the rest of the + + + align:start position:0% +if and now you negate the rest of the +definition + + align:start position:0% +definition + + + align:start position:0% +definition +if there exists some bad epsilon + + align:start position:0% +if there exists some bad epsilon + + + align:start position:0% +if there exists some bad epsilon +such that no matter what delta you + + align:start position:0% +such that no matter what delta you + + + align:start position:0% +such that no matter what delta you +choose + + align:start position:0% + + + + align:start position:0% + +there exists some bad x and c + + align:start position:0% + + + + align:start position:0% + +and s + + align:start position:0% +and s + + + align:start position:0% +and s +such that + + align:start position:0% +such that + + + align:start position:0% +such that +they're close to each other + + align:start position:0% +they're close to each other + + + align:start position:0% +they're close to each other +but the values are not + + align:start position:0% + + + + align:start position:0% + +bigger than or equal to + + align:start position:0% +bigger than or equal to + + + align:start position:0% +bigger than or equal to +okay + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +let's + + align:start position:0% + + + + align:start position:0% + +revisit one over x + + align:start position:0% + + + + align:start position:0% + +this is not + + align:start position:0% +this is not + + + align:start position:0% +this is not +uniformly continuous + + align:start position:0% + + + + align:start position:0% + +on + + align:start position:0% +on + + + align:start position:0% +on +the open interval 0 1. so you see that + + align:start position:0% +the open interval 0 1. so you see that + + + align:start position:0% +the open interval 0 1. so you see that +this function is continuous but it's not + + align:start position:0% +this function is continuous but it's not + + + align:start position:0% +this function is continuous but it's not +uniformly continuous all right + + align:start position:0% +uniformly continuous all right + + + align:start position:0% +uniformly continuous all right +so we just proved that a minute ago that + + align:start position:0% +so we just proved that a minute ago that + + + align:start position:0% +so we just proved that a minute ago that +it's continuous so let me now + + align:start position:0% +it's continuous so let me now + + + align:start position:0% +it's continuous so let me now +give you the proof that this function is + + align:start position:0% +give you the proof that this function is + + + align:start position:0% +give you the proof that this function is +not uniformly continuous and what's the + + align:start position:0% +not uniformly continuous and what's the + + + align:start position:0% +not uniformly continuous and what's the +idea + + align:start position:0% +idea + + + align:start position:0% +idea +behind this + + align:start position:0% +behind this + + + align:start position:0% +behind this +here's one + + align:start position:0% +here's one + + + align:start position:0% +here's one +okay this is not to scale but there's + + align:start position:0% +okay this is not to scale but there's + + + align:start position:0% +okay this is not to scale but there's +one + + align:start position:0% +one + + + align:start position:0% +one +as well and + + align:start position:0% +as well and + + + align:start position:0% +as well and +one over x + + align:start position:0% + + + + align:start position:0% + +you know + + align:start position:0% +you know + + + align:start position:0% +you know +shoots up to plus infinity as x + + align:start position:0% +shoots up to plus infinity as x + + + align:start position:0% +shoots up to plus infinity as x +approaches zero + + align:start position:0% +approaches zero + + + align:start position:0% +approaches zero +right + + align:start position:0% +right + + + align:start position:0% +right +and + + align:start position:0% +and + + + align:start position:0% +and +so what uniform continuity says is that + + align:start position:0% +so what uniform continuity says is that + + + align:start position:0% +so what uniform continuity says is that +if i take any two points in the interval + + align:start position:0% +if i take any two points in the interval + + + align:start position:0% +if i take any two points in the interval +that are close to each other then the + + align:start position:0% +that are close to each other then the + + + align:start position:0% +that are close to each other then the +outputs have to be close to each other + + align:start position:0% +outputs have to be close to each other + + + align:start position:0% +outputs have to be close to each other +all right + + align:start position:0% +all right + + + align:start position:0% +all right +continuity remember says if i fix a + + align:start position:0% +continuity remember says if i fix a + + + align:start position:0% +continuity remember says if i fix a +point + + align:start position:0% +point + + + align:start position:0% +point +then as long as i'm close to that point + + align:start position:0% +then as long as i'm close to that point + + + align:start position:0% +then as long as i'm close to that point +the outputs will be close to each other + + align:start position:0% +the outputs will be close to each other + + + align:start position:0% +the outputs will be close to each other +uniform says no matter what two points + + align:start position:0% +uniform says no matter what two points + + + align:start position:0% +uniform says no matter what two points +you choose as long as they're close + + align:start position:0% +you choose as long as they're close + + + align:start position:0% +you choose as long as they're close +together + + align:start position:0% +together + + + align:start position:0% +together +the outputs will be close together in a + + align:start position:0% +the outputs will be close together in a + + + align:start position:0% +the outputs will be close together in a +controlled way now if i take + + align:start position:0% +controlled way now if i take + + + align:start position:0% +controlled way now if i take +two points + + align:start position:0% +two points + + + align:start position:0% +two points +very close to each other here very close + + align:start position:0% +very close to each other here very close + + + align:start position:0% +very close to each other here very close +to zero + + align:start position:0% +to zero + + + align:start position:0% +to zero +they can be you know pretty close to + + align:start position:0% +they can be you know pretty close to + + + align:start position:0% +they can be you know pretty close to +each other + + align:start position:0% +each other + + + align:start position:0% +each other +but their differences + + align:start position:0% +but their differences + + + align:start position:0% +but their differences +i mean their values + + align:start position:0% + + + + align:start position:0% + +can be + + align:start position:0% + + + + align:start position:0% + +quite large + + align:start position:0% +quite large + + + align:start position:0% +quite large +even though + + align:start position:0% + + + + align:start position:0% + +the difference between the + + align:start position:0% +the difference between the + + + align:start position:0% +the difference between the +arguments are small the values can be + + align:start position:0% +arguments are small the values can be + + + align:start position:0% +arguments are small the values can be +quite large just because 1 over x + + align:start position:0% +quite large just because 1 over x + + + align:start position:0% +quite large just because 1 over x +shoots up so + + align:start position:0% +shoots up so + + + align:start position:0% +shoots up so +let's quantify this i have to tell you + + align:start position:0% +let's quantify this i have to tell you + + + align:start position:0% +let's quantify this i have to tell you +what the bad epsilon knot is + + align:start position:0% + + + + align:start position:0% + +choose epsilon not equals 2. now any + + align:start position:0% +choose epsilon not equals 2. now any + + + align:start position:0% +choose epsilon not equals 2. now any +epsilon naught + + align:start position:0% +epsilon naught + + + align:start position:0% +epsilon naught +will work just fine + + align:start position:0% + + + + align:start position:0% + +let uh + + align:start position:0% +let uh + + + align:start position:0% +let uh +delta be positive so now we have to find + + align:start position:0% +delta be positive so now we have to find + + + align:start position:0% +delta be positive so now we have to find +x and c + + align:start position:0% +x and c + + + align:start position:0% +x and c +n s uh within distance delta to each + + align:start position:0% +n s uh within distance delta to each + + + align:start position:0% +n s uh within distance delta to each +other + + align:start position:0% + + + + align:start position:0% + +that + + align:start position:0% +that + + + align:start position:0% +that +whose values different differ very uh by + + align:start position:0% +whose values different differ very uh by + + + align:start position:0% +whose values different differ very uh by +at least two + + align:start position:0% +at least two + + + align:start position:0% +at least two +so let's choose + + align:start position:0% + + + + align:start position:0% + +c to be + + align:start position:0% + + + + align:start position:0% + +the minimum of + + align:start position:0% +the minimum of + + + align:start position:0% +the minimum of +delta and a half + + align:start position:0% +delta and a half + + + align:start position:0% +delta and a half +and i'm going to choose x to be + + align:start position:0% +and i'm going to choose x to be + + + align:start position:0% +and i'm going to choose x to be +c over 2. + + align:start position:0% +c over 2. + + + align:start position:0% +c over 2. +okay + + align:start position:0% + + + + align:start position:0% + +so just ignoring this half for a minute + + align:start position:0% +so just ignoring this half for a minute + + + align:start position:0% +so just ignoring this half for a minute +c is equal to delta x is equal to delta + + align:start position:0% +c is equal to delta x is equal to delta + + + align:start position:0% +c is equal to delta x is equal to delta +over 2 + + align:start position:0% +over 2 + + + align:start position:0% +over 2 +and then 1 over c minus one over x is + + align:start position:0% +and then 1 over c minus one over x is + + + align:start position:0% +and then 1 over c minus one over x is +going to be two over delta and if delta + + align:start position:0% +going to be two over delta and if delta + + + align:start position:0% +going to be two over delta and if delta +is very small that's certainly bigger + + align:start position:0% +is very small that's certainly bigger + + + align:start position:0% +is very small that's certainly bigger +than or equal to two but i had to throw + + align:start position:0% +than or equal to two but i had to throw + + + align:start position:0% +than or equal to two but i had to throw +in this one half here because i chose + + align:start position:0% +in this one half here because i chose + + + align:start position:0% +in this one half here because i chose +epsilon not to be two + + align:start position:0% +epsilon not to be two + + + align:start position:0% +epsilon not to be two +all right and delta's arbitrary + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +then we see that x minus c + + align:start position:0% +then we see that x minus c + + + align:start position:0% +then we see that x minus c +this equals c over two + + align:start position:0% +this equals c over two + + + align:start position:0% +this equals c over two +which is certainly less than or equal to + + align:start position:0% +which is certainly less than or equal to + + + align:start position:0% +which is certainly less than or equal to +since c is the minimum of delta and one + + align:start position:0% +since c is the minimum of delta and one + + + align:start position:0% +since c is the minimum of delta and one +over half is less than delta over two + + align:start position:0% +over half is less than delta over two + + + align:start position:0% +over half is less than delta over two +which is less than delta + + align:start position:0% + + + + align:start position:0% + +and if we compute + + align:start position:0% +and if we compute + + + align:start position:0% +and if we compute +one over x minus one over c + + align:start position:0% +one over x minus one over c + + + align:start position:0% +one over x minus one over c +this is uh + + align:start position:0% + + + + align:start position:0% + +remember x is c over two so this one + + align:start position:0% +remember x is c over two so this one + + + align:start position:0% +remember x is c over two so this one +over x is two over c + + align:start position:0% +over x is two over c + + + align:start position:0% +over x is two over c +so + + align:start position:0% +so + + + align:start position:0% +so +1 over c + + align:start position:0% + + + + align:start position:0% + +right + + align:start position:0% +right + + + align:start position:0% +right +and now + + align:start position:0% +and now + + + align:start position:0% +and now +from c + + align:start position:0% +from c + + + align:start position:0% +from c +being less than or equal to + + align:start position:0% +being less than or equal to + + + align:start position:0% +being less than or equal to +1 over half i get that 1 over c is going + + align:start position:0% +1 over half i get that 1 over c is going + + + align:start position:0% +1 over half i get that 1 over c is going +to be bigger than or equal to 2. + + align:start position:0% + + + + align:start position:0% + +all right + + align:start position:0% +all right + + + align:start position:0% +all right +and that's the end of the proof + + align:start position:0% +and that's the end of the proof + + + align:start position:0% +and that's the end of the proof +right so we see that even though + + align:start position:0% +right so we see that even though + + + align:start position:0% +right so we see that even though +these two uh + + align:start position:0% +these two uh + + + align:start position:0% +these two uh +these two arguments are very close to + + align:start position:0% +these two arguments are very close to + + + align:start position:0% +these two arguments are very close to +each other the outputs are in fact you + + align:start position:0% +each other the outputs are in fact you + + + align:start position:0% +each other the outputs are in fact you +know + + align:start position:0% +know + + + align:start position:0% +know +separated + + align:start position:0% +separated + + + align:start position:0% +separated +by some fixed distance + + align:start position:0% +by some fixed distance + + + align:start position:0% +by some fixed distance +at least two + + align:start position:0% +at least two + + + align:start position:0% +at least two +but we could actually make it you know + + align:start position:0% +but we could actually make it you know + + + align:start position:0% +but we could actually make it you know +bigger than three bigger than four + + align:start position:0% +bigger than three bigger than four + + + align:start position:0% +bigger than three bigger than four +whatever you like all right + + align:start position:0% +whatever you like all right + + + align:start position:0% +whatever you like all right +[Applause] + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and i'm not going to go over this + + align:start position:0% +and i'm not going to go over this + + + align:start position:0% +and i'm not going to go over this +example + + align:start position:0% + + + + align:start position:0% + +but in fact + + align:start position:0% + + + + align:start position:0% + +i'll leave it to you or maybe i'll put + + align:start position:0% +i'll leave it to you or maybe i'll put + + + align:start position:0% +i'll leave it to you or maybe i'll put +it on the assignment f of x equals x + + align:start position:0% +it on the assignment f of x equals x + + + align:start position:0% +it on the assignment f of x equals x +squared + + align:start position:0% + + + + align:start position:0% + +is not + + align:start position:0% + + + + align:start position:0% + +uniformly continuous on + + align:start position:0% +uniformly continuous on + + + align:start position:0% +uniformly continuous on +r so we should we saw that it's + + align:start position:0% +r so we should we saw that it's + + + align:start position:0% +r so we should we saw that it's +uniformly continuous on the closed + + align:start position:0% +uniformly continuous on the closed + + + align:start position:0% +uniformly continuous on the closed +interval 0 1 + + align:start position:0% +interval 0 1 + + + align:start position:0% +interval 0 1 +but it's not uniformly continuous on + + align:start position:0% +but it's not uniformly continuous on + + + align:start position:0% +but it's not uniformly continuous on +all of r okay + + align:start position:0% +all of r okay + + + align:start position:0% +all of r okay +the reason being again kind of because + + align:start position:0% +the reason being again kind of because + + + align:start position:0% +the reason being again kind of because +you know x squared is starting to get + + align:start position:0% +you know x squared is starting to get + + + align:start position:0% +you know x squared is starting to get +big so i can take two things close to + + align:start position:0% +big so i can take two things close to + + + align:start position:0% +big so i can take two things close to +each other stick it into x squared and + + align:start position:0% +each other stick it into x squared and + + + align:start position:0% +each other stick it into x squared and +their outputs could be you know very + + align:start position:0% +their outputs could be you know very + + + align:start position:0% +their outputs could be you know very +different from each other + + align:start position:0% + + + + align:start position:0% + +i didn't write out the proof of this one + + align:start position:0% +i didn't write out the proof of this one + + + align:start position:0% +i didn't write out the proof of this one +so we're going to go a little bit by + + align:start position:0% + + + + align:start position:0% + +a little bit by the seat of our pants + + align:start position:0% + + + + align:start position:0% + +so we want to show this is not uniformly + + align:start position:0% +so we want to show this is not uniformly + + + align:start position:0% +so we want to show this is not uniformly +continuous so + + align:start position:0% + + + + align:start position:0% + +i think epsilon 0 equals 1 is going to + + align:start position:0% +i think epsilon 0 equals 1 is going to + + + align:start position:0% +i think epsilon 0 equals 1 is going to +work just fine + + align:start position:0% + + + + align:start position:0% + +that delta b positive + + align:start position:0% +that delta b positive + + + align:start position:0% +that delta b positive +and the idea + + align:start position:0% +and the idea + + + align:start position:0% +and the idea +is we want to choose + + align:start position:0% +is we want to choose + + + align:start position:0% +is we want to choose +x to be + + align:start position:0% +x to be + + + align:start position:0% +x to be +some number + + align:start position:0% +some number + + + align:start position:0% +some number +let's call it a + + align:start position:0% + + + + align:start position:0% + +plus + + align:start position:0% + + + + align:start position:0% + +well + + align:start position:0% +well + + + align:start position:0% +well +c will be some number + + align:start position:0% +c will be some number + + + align:start position:0% +c will be some number +and + + align:start position:0% +and + + + align:start position:0% +and +c equals + + align:start position:0% + + + + align:start position:0% + +some number + + align:start position:0% +some number + + + align:start position:0% +some number +x equals c + + align:start position:0% +x equals c + + + align:start position:0% +x equals c +plus + + align:start position:0% +plus + + + align:start position:0% +plus +delta over two okay so this is kind of + + align:start position:0% +delta over two okay so this is kind of + + + align:start position:0% +delta over two okay so this is kind of +scratch work off to the side and let's + + align:start position:0% +scratch work off to the side and let's + + + align:start position:0% +scratch work off to the side and let's +see if we can somehow choose c + + align:start position:0% +see if we can somehow choose c + + + align:start position:0% +see if we can somehow choose c +so that um so first off + + align:start position:0% +so that um so first off + + + align:start position:0% +so that um so first off +um + + align:start position:0% +um + + + align:start position:0% +um +you know x minus c + + align:start position:0% +you know x minus c + + + align:start position:0% +you know x minus c +will be c over 2 + + align:start position:0% +will be c over 2 + + + align:start position:0% +will be c over 2 +will be delta over 2 which is less than + + align:start position:0% +will be delta over 2 which is less than + + + align:start position:0% +will be delta over 2 which is less than +delta + + align:start position:0% +delta + + + align:start position:0% +delta +and now let's see + + align:start position:0% +and now let's see + + + align:start position:0% +and now let's see +if we can + + align:start position:0% + + + + align:start position:0% + +choose c + + align:start position:0% +choose c + + + align:start position:0% +choose c +so that + + align:start position:0% +so that + + + align:start position:0% +so that +x squared minus c squared + + align:start position:0% +x squared minus c squared + + + align:start position:0% +x squared minus c squared +is + + align:start position:0% +is + + + align:start position:0% +is +bigger than or equal to one + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +c is is + + align:start position:0% +c is is + + + align:start position:0% +c is is +kind of the thing that we get to play + + align:start position:0% +kind of the thing that we get to play + + + align:start position:0% +kind of the thing that we get to play +with here + + align:start position:0% +with here + + + align:start position:0% +with here +i mean this is how it actually goes + + align:start position:0% +i mean this is how it actually goes + + + align:start position:0% +i mean this is how it actually goes +uh if you're one to you know figure out + + align:start position:0% +uh if you're one to you know figure out + + + align:start position:0% +uh if you're one to you know figure out +the proof before you write it down you + + align:start position:0% +the proof before you write it down you + + + align:start position:0% +the proof before you write it down you +know the scratch work to the side + + align:start position:0% +know the scratch work to the side + + + align:start position:0% +know the scratch work to the side +all right so + + align:start position:0% +all right so + + + align:start position:0% +all right so +choose c so that this now + + align:start position:0% +choose c so that this now + + + align:start position:0% +choose c so that this now +let's start off with + + align:start position:0% +let's start off with + + + align:start position:0% +let's start off with +the thing that we're trying to bound + + align:start position:0% +the thing that we're trying to bound + + + align:start position:0% +the thing that we're trying to bound +from below and start computing some + + align:start position:0% +from below and start computing some + + + align:start position:0% +from below and start computing some +stuff + + align:start position:0% +stuff + + + align:start position:0% +stuff +this is equal to x plus c and c will be + + align:start position:0% +this is equal to x plus c and c will be + + + align:start position:0% +this is equal to x plus c and c will be +positive okay so + + align:start position:0% +positive okay so + + + align:start position:0% +positive okay so +um this will be + + align:start position:0% +um this will be + + + align:start position:0% +um this will be +c and x will be positive so x plus c + + align:start position:0% + + + + align:start position:0% + +times x minus c + + align:start position:0% +times x minus c + + + align:start position:0% +times x minus c +now x plus c + + align:start position:0% +now x plus c + + + align:start position:0% +now x plus c +will be + + align:start position:0% + + + + align:start position:0% + +2c plus + + align:start position:0% +2c plus + + + align:start position:0% +2c plus +delta over two + + align:start position:0% + + + + align:start position:0% + +x minus c will be + + align:start position:0% +x minus c will be + + + align:start position:0% +x minus c will be +delta over two + + align:start position:0% + + + + align:start position:0% + +so so far all of these things are + + align:start position:0% +so so far all of these things are + + + align:start position:0% +so so far all of these things are +equality + + align:start position:0% +equality + + + align:start position:0% +equality +and we get this is equal to + + align:start position:0% +and we get this is equal to + + + align:start position:0% +and we get this is equal to +2c + + align:start position:0% +2c + + + align:start position:0% +2c +plus + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +delta + + align:start position:0% +delta + + + align:start position:0% +delta +is 2c plus delta squared over two + + align:start position:0% +is 2c plus delta squared over two + + + align:start position:0% +is 2c plus delta squared over two +and here we're going to choose c + + align:start position:0% +and here we're going to choose c + + + align:start position:0% +and here we're going to choose c +positive right so we're trying to show + + align:start position:0% +positive right so we're trying to show + + + align:start position:0% +positive right so we're trying to show +it's not uniformly continuous on r + + align:start position:0% +it's not uniformly continuous on r + + + align:start position:0% +it's not uniformly continuous on r +so we just need to find a value of c and + + align:start position:0% +so we just need to find a value of c and + + + align:start position:0% +so we just need to find a value of c and +a value of x + + align:start position:0% + + + + align:start position:0% + +so that they're within delta distance to + + align:start position:0% +so that they're within delta distance to + + + align:start position:0% +so that they're within delta distance to +each other but their outputs are bigger + + align:start position:0% +each other but their outputs are bigger + + + align:start position:0% +each other but their outputs are bigger +than or equal to one + + align:start position:0% +than or equal to one + + + align:start position:0% +than or equal to one +so + + align:start position:0% +so + + + align:start position:0% +so +so far if c is just something positive x + + align:start position:0% +so far if c is just something positive x + + + align:start position:0% +so far if c is just something positive x +is c plus delta over two then they're + + align:start position:0% +is c plus delta over two then they're + + + align:start position:0% +is c plus delta over two then they're +close + + align:start position:0% +close + + + align:start position:0% +close +their difference however is going to be + + align:start position:0% +their difference however is going to be + + + align:start position:0% +their difference however is going to be +just by this computation + + align:start position:0% +just by this computation + + + align:start position:0% +just by this computation +equal to + + align:start position:0% +equal to + + + align:start position:0% +equal to +2c plus delta over 2 times delta over 2 + + align:start position:0% +2c plus delta over 2 times delta over 2 + + + align:start position:0% +2c plus delta over 2 times delta over 2 +squared + + align:start position:0% +squared + + + align:start position:0% +squared +now delta squared over 2 is always + + align:start position:0% +now delta squared over 2 is always + + + align:start position:0% +now delta squared over 2 is always +non-negative so it's certainly bigger + + align:start position:0% +non-negative so it's certainly bigger + + + align:start position:0% +non-negative so it's certainly bigger +than or equal to delta times c + + align:start position:0% +than or equal to delta times c + + + align:start position:0% +than or equal to delta times c +and + + align:start position:0% +and + + + align:start position:0% +and +now remember we wanted this thing to be + + align:start position:0% +now remember we wanted this thing to be + + + align:start position:0% +now remember we wanted this thing to be +bigger than or equal to one right now we + + align:start position:0% +bigger than or equal to one right now we + + + align:start position:0% +bigger than or equal to one right now we +have it's bigger than or equal to delta + + align:start position:0% +have it's bigger than or equal to delta + + + align:start position:0% +have it's bigger than or equal to delta +c + + align:start position:0% +c + + + align:start position:0% +c +so let's choose c to be + + align:start position:0% +so let's choose c to be + + + align:start position:0% +so let's choose c to be +one over delta + + align:start position:0% +one over delta + + + align:start position:0% +one over delta +okay + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% +and + + + align:start position:0% +and +let's see that that works + + align:start position:0% + + + + align:start position:0% + +choose + + align:start position:0% +choose + + + align:start position:0% +choose +c to be 1 over delta + + align:start position:0% +c to be 1 over delta + + + align:start position:0% +c to be 1 over delta +x to be + + align:start position:0% +x to be + + + align:start position:0% +x to be +1 over delta so c plus + + align:start position:0% +1 over delta so c plus + + + align:start position:0% +1 over delta so c plus +delta over 2. + + align:start position:0% + + + + align:start position:0% + +then these two values are close + + align:start position:0% +then these two values are close + + + align:start position:0% +then these two values are close +x minus c equals + + align:start position:0% +x minus c equals + + + align:start position:0% +x minus c equals +delta over 2 + + align:start position:0% +delta over 2 + + + align:start position:0% +delta over 2 +is less than delta + + align:start position:0% +is less than delta + + + align:start position:0% +is less than delta +and + + align:start position:0% +and + + + align:start position:0% +and +x squared minus c squared + + align:start position:0% +x squared minus c squared + + + align:start position:0% +x squared minus c squared +equals x plus c + + align:start position:0% +equals x plus c + + + align:start position:0% +equals x plus c +times x + + align:start position:0% +times x + + + align:start position:0% +times x +minus c + + align:start position:0% + + + + align:start position:0% + +x plus c as we did a minute ago is going + + align:start position:0% +x plus c as we did a minute ago is going + + + align:start position:0% +x plus c as we did a minute ago is going +to be + + align:start position:0% + + + + align:start position:0% + +2 over delta plus delta over 2 that's x + + align:start position:0% +2 over delta plus delta over 2 that's x + + + align:start position:0% +2 over delta plus delta over 2 that's x +plus c + + align:start position:0% +plus c + + + align:start position:0% +plus c +x minus c is equal to delta over 2. + + align:start position:0% +x minus c is equal to delta over 2. + + + align:start position:0% +x minus c is equal to delta over 2. +which equals 1 plus + + align:start position:0% +which equals 1 plus + + + align:start position:0% +which equals 1 plus +delta squared over 4 which is bigger + + align:start position:0% +delta squared over 4 which is bigger + + + align:start position:0% +delta squared over 4 which is bigger +than or equal to 1 + + align:start position:0% +than or equal to 1 + + + align:start position:0% +than or equal to 1 +our bad epsilon okay so + + align:start position:0% +our bad epsilon okay so + + + align:start position:0% +our bad epsilon okay so +f of x equals x squared is not uniformly + + align:start position:0% +f of x equals x squared is not uniformly + + + align:start position:0% +f of x equals x squared is not uniformly +continuous on r + + align:start position:0% +continuous on r + + + align:start position:0% +continuous on r +even though it is uniformly continuous + + align:start position:0% +even though it is uniformly continuous + + + align:start position:0% +even though it is uniformly continuous +on this closed and bounded interval + + align:start position:0% +on this closed and bounded interval + + + align:start position:0% +on this closed and bounded interval +okay + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +um + + align:start position:0% +um + + + align:start position:0% +um +you know uniform continuity is really a + + align:start position:0% +you know uniform continuity is really a + + + align:start position:0% +you know uniform continuity is really a +relationship between a function + + align:start position:0% +relationship between a function + + + align:start position:0% +relationship between a function +and + + align:start position:0% +and + + + align:start position:0% +and +you know the the domain on which it's + + align:start position:0% +you know the the domain on which it's + + + align:start position:0% +you know the the domain on which it's +defined + + align:start position:0% +defined + + + align:start position:0% +defined +okay + + align:start position:0% + + + + align:start position:0% + +but okay so this is uh kind of to wrap + + align:start position:0% +but okay so this is uh kind of to wrap + + + align:start position:0% +but okay so this is uh kind of to wrap +up + + align:start position:0% +up + + + align:start position:0% +up +our theme of + + align:start position:0% +our theme of + + + align:start position:0% +our theme of +continuous functions + + align:start position:0% +continuous functions + + + align:start position:0% +continuous functions +and how they're behaved on closed and + + align:start position:0% +and how they're behaved on closed and + + + align:start position:0% +and how they're behaved on closed and +bounded intervals and we see here that + + align:start position:0% +bounded intervals and we see here that + + + align:start position:0% +bounded intervals and we see here that +you know uniform continuity is a much + + align:start position:0% +you know uniform continuity is a much + + + align:start position:0% +you know uniform continuity is a much +stronger notion than + + align:start position:0% +stronger notion than + + + align:start position:0% +stronger notion than +continuity as i've said i mean you can + + align:start position:0% +continuity as i've said i mean you can + + + align:start position:0% +continuity as i've said i mean you can +easily prove from the definition that if + + align:start position:0% +easily prove from the definition that if + + + align:start position:0% +easily prove from the definition that if +a function is uniformly continuous on s + + align:start position:0% +a function is uniformly continuous on s + + + align:start position:0% +a function is uniformly continuous on s +then it's continuous on s + + align:start position:0% +then it's continuous on s + + + align:start position:0% +then it's continuous on s +all right + + align:start position:0% +all right + + + align:start position:0% +all right +now + + align:start position:0% + + + + align:start position:0% + +and we've seen that in general + + align:start position:0% +and we've seen that in general + + + align:start position:0% +and we've seen that in general +the reverse inclusion does not hold so + + align:start position:0% +the reverse inclusion does not hold so + + + align:start position:0% +the reverse inclusion does not hold so +let me just write this up + + align:start position:0% +let me just write this up + + + align:start position:0% +let me just write this up +as a remark + + align:start position:0% + + + + align:start position:0% + +in general + + align:start position:0% +in general + + + align:start position:0% +in general +f + + align:start position:0% + + + + align:start position:0% + +uniformly continuous + + align:start position:0% +uniformly continuous + + + align:start position:0% +uniformly continuous +implies that + + align:start position:0% +implies that + + + align:start position:0% +implies that +f is + + align:start position:0% +f is + + + align:start position:0% +f is +continuous this just follows from the + + align:start position:0% +continuous this just follows from the + + + align:start position:0% +continuous this just follows from the +definition okay this is not difficult to + + align:start position:0% +definition okay this is not difficult to + + + align:start position:0% +definition okay this is not difficult to +show + + align:start position:0% + + + + align:start position:0% + +but + + align:start position:0% +but + + + align:start position:0% +but +the converse does not hold + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +as we've just seen right we have two + + align:start position:0% +as we've just seen right we have two + + + align:start position:0% +as we've just seen right we have two +examples here f of x equals one over x + + align:start position:0% +examples here f of x equals one over x + + + align:start position:0% +examples here f of x equals one over x +on the open interval zero one which is + + align:start position:0% +on the open interval zero one which is + + + align:start position:0% +on the open interval zero one which is +continuous but it's not uniformly + + align:start position:0% +continuous but it's not uniformly + + + align:start position:0% +continuous but it's not uniformly +continuous and then we have the function + + align:start position:0% +continuous and then we have the function + + + align:start position:0% +continuous and then we have the function +f of x equals x squared which is + + align:start position:0% +f of x equals x squared which is + + + align:start position:0% +f of x equals x squared which is +not uniformly continuous on r but in + + align:start position:0% +not uniformly continuous on r but in + + + align:start position:0% +not uniformly continuous on r but in +fact it is uniformly continuous on this + + align:start position:0% +fact it is uniformly continuous on this + + + align:start position:0% +fact it is uniformly continuous on this +closed and bounded interval zero one + + align:start position:0% +closed and bounded interval zero one + + + align:start position:0% +closed and bounded interval zero one +this example here though is in fact the + + align:start position:0% +this example here though is in fact the + + + align:start position:0% +this example here though is in fact the +rule + + align:start position:0% +rule + + + align:start position:0% +rule +that if i'm looking at + + align:start position:0% +that if i'm looking at + + + align:start position:0% +that if i'm looking at +a continuous function + + align:start position:0% +a continuous function + + + align:start position:0% +a continuous function +or a function on my closed and bounded + + align:start position:0% +or a function on my closed and bounded + + + align:start position:0% +or a function on my closed and bounded +interval then in fact + + align:start position:0% +interval then in fact + + + align:start position:0% +interval then in fact +these two notions are equivalent so + + align:start position:0% +these two notions are equivalent so + + + align:start position:0% +these two notions are equivalent so +that's the the following theorem + + align:start position:0% + + + + align:start position:0% + +let f + + align:start position:0% +let f + + + align:start position:0% +let f +be a function from + + align:start position:0% +be a function from + + + align:start position:0% +be a function from +a to b to r + + align:start position:0% +a to b to r + + + align:start position:0% +a to b to r +so a closed and bounded interval now not + + align:start position:0% +so a closed and bounded interval now not + + + align:start position:0% +so a closed and bounded interval now not +just an arbitrary set + + align:start position:0% + + + + align:start position:0% + +then + + align:start position:0% +then + + + align:start position:0% +then +f is + + align:start position:0% +f is + + + align:start position:0% +f is +continuous + + align:start position:0% +continuous + + + align:start position:0% +continuous +on a b meaning it's continuous at every + + align:start position:0% +on a b meaning it's continuous at every + + + align:start position:0% +on a b meaning it's continuous at every +point + + align:start position:0% + + + + align:start position:0% + +if and only if + + align:start position:0% +if and only if + + + align:start position:0% +if and only if +f is + + align:start position:0% +f is + + + align:start position:0% +f is +uniformly continuous + + align:start position:0% + + + + align:start position:0% + +on a b okay + + align:start position:0% +on a b okay + + + align:start position:0% +on a b okay +and the necessity of being working on a + + align:start position:0% +and the necessity of being working on a + + + align:start position:0% +and the necessity of being working on a +closed and bounded interval + + align:start position:0% +closed and bounded interval + + + align:start position:0% +closed and bounded interval +um is seen again by these uh examples we + + align:start position:0% +um is seen again by these uh examples we + + + align:start position:0% +um is seen again by these uh examples we +by this example we had here of f of x + + align:start position:0% +by this example we had here of f of x + + + align:start position:0% +by this example we had here of f of x +equals one over x and f of x equals x + + align:start position:0% +equals one over x and f of x equals x + + + align:start position:0% +equals one over x and f of x equals x +squared on r and zero one okay + + align:start position:0% +squared on r and zero one okay + + + align:start position:0% +squared on r and zero one okay +but as long as we're looking on a closed + + align:start position:0% +but as long as we're looking on a closed + + + align:start position:0% +but as long as we're looking on a closed +and bounded interval + + align:start position:0% +and bounded interval + + + align:start position:0% +and bounded interval +uh continuous is equivalent to uniform + + align:start position:0% +uh continuous is equivalent to uniform + + + align:start position:0% +uh continuous is equivalent to uniform +continuity + + align:start position:0% +continuity + + + align:start position:0% +continuity +all right now this is also not the + + align:start position:0% +all right now this is also not the + + + align:start position:0% +all right now this is also not the +sharpest thing you can say + + align:start position:0% +sharpest thing you can say + + + align:start position:0% +sharpest thing you can say +um + + align:start position:0% + + + + align:start position:0% + +in fact + + align:start position:0% +in fact + + + align:start position:0% +in fact +what you can say is that if i replace + + align:start position:0% +what you can say is that if i replace + + + align:start position:0% +what you can say is that if i replace +this with what's called a compact set uh + + align:start position:0% +this with what's called a compact set uh + + + align:start position:0% +this with what's called a compact set uh +which i may put in the assignment i may + + align:start position:0% +which i may put in the assignment i may + + + align:start position:0% +which i may put in the assignment i may +not then this statement is still true + + align:start position:0% +not then this statement is still true + + + align:start position:0% +not then this statement is still true +and that's in some sense the sharpest uh + + align:start position:0% +and that's in some sense the sharpest uh + + + align:start position:0% +and that's in some sense the sharpest uh +statement but + + align:start position:0% +statement but + + + align:start position:0% +statement but +i think this is interesting enough + + align:start position:0% + + + + align:start position:0% + +to just work on a closed and bounded + + align:start position:0% +to just work on a closed and bounded + + + align:start position:0% +to just work on a closed and bounded +interval + + align:start position:0% +interval + + + align:start position:0% +interval +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so + + align:start position:0% +so + + + align:start position:0% +so +let's prove this + + align:start position:0% + + + + align:start position:0% + +so again this direction + + align:start position:0% +so again this direction + + + align:start position:0% +so again this direction +uh + + align:start position:0% +uh + + + align:start position:0% +uh +i should say + + align:start position:0% + + + + align:start position:0% + +i leave this to you as an exercise + + align:start position:0% + + + + align:start position:0% + +uniform continuity implying uh + + align:start position:0% +uniform continuity implying uh + + + align:start position:0% +uniform continuity implying uh +continuity and leave it to you + + align:start position:0% + + + + align:start position:0% + +and i will do + + align:start position:0% +and i will do + + + align:start position:0% +and i will do +more difficult one + + align:start position:0% + + + + align:start position:0% + +and we'll use use kind of a + + align:start position:0% +and we'll use use kind of a + + + align:start position:0% +and we'll use use kind of a +you know philosophy like we did + + align:start position:0% +you know philosophy like we did + + + align:start position:0% +you know philosophy like we did +in the previous lecture where we used + + align:start position:0% +in the previous lecture where we used + + + align:start position:0% +in the previous lecture where we used +the definition of continuity or this + + align:start position:0% +the definition of continuity or this + + + align:start position:0% +the definition of continuity or this +theorem about + + align:start position:0% +theorem about + + + align:start position:0% +theorem about +uh continuity in terms of sequences and + + align:start position:0% +uh continuity in terms of sequences and + + + align:start position:0% +uh continuity in terms of sequences and +also the bolzano virus cross + + align:start position:0% +also the bolzano virus cross + + + align:start position:0% +also the bolzano virus cross +here + + align:start position:0% + + + + align:start position:0% + +okay good we still have the negation of + + align:start position:0% +okay good we still have the negation of + + + align:start position:0% +okay good we still have the negation of +the definition of uniform continuity + + align:start position:0% + + + + align:start position:0% + +and that's what we'll need + + align:start position:0% + + + + align:start position:0% + +all right so we're going to prove + + align:start position:0% + + + + align:start position:0% + +f continuous implies uniformly + + align:start position:0% +f continuous implies uniformly + + + align:start position:0% +f continuous implies uniformly +continuous and we're going to do this by + + align:start position:0% +continuous and we're going to do this by + + + align:start position:0% +continuous and we're going to do this by +contradiction so + + align:start position:0% +contradiction so + + + align:start position:0% +contradiction so +suppose f + + align:start position:0% + + + + align:start position:0% + +is continuous on a b but not uniformly + + align:start position:0% +is continuous on a b but not uniformly + + + align:start position:0% +is continuous on a b but not uniformly +continuous + + align:start position:0% + + + + align:start position:0% + +all right and then we're gonna + + align:start position:0% + + + + align:start position:0% + +break the universe + + align:start position:0% +break the universe + + + align:start position:0% +break the universe +some way + + align:start position:0% +some way + + + align:start position:0% +some way +all right + + align:start position:0% + + + + align:start position:0% + +which shows that our assumption that f + + align:start position:0% +which shows that our assumption that f + + + align:start position:0% +which shows that our assumption that f +is not uniformly continuous + + align:start position:0% +is not uniformly continuous + + + align:start position:0% +is not uniformly continuous +does not hold + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +so we use + + align:start position:0% +so we use + + + align:start position:0% +so we use +this negation of the definition of + + align:start position:0% +this negation of the definition of + + + align:start position:0% +this negation of the definition of +uniform continuity + + align:start position:0% +uniform continuity + + + align:start position:0% +uniform continuity +which says for + + align:start position:0% +which says for + + + align:start position:0% +which says for +that there exists a delta zero so let me + + align:start position:0% +that there exists a delta zero so let me + + + align:start position:0% +that there exists a delta zero so let me +write this out + + align:start position:0% + + + + align:start position:0% + +i'm just going to rewrite this here then + + align:start position:0% +i'm just going to rewrite this here then + + + align:start position:0% +i'm just going to rewrite this here then +there exists a delta 0 such that for all + + align:start position:0% +there exists a delta 0 such that for all + + + align:start position:0% +there exists a delta 0 such that for all +delta positive there exists x + + align:start position:0% +delta positive there exists x + + + align:start position:0% +delta positive there exists x +c + + align:start position:0% +c + + + align:start position:0% +c +and + + align:start position:0% +and + + + align:start position:0% +and +a b + + align:start position:0% +a b + + + align:start position:0% +a b +which depend on delta + + align:start position:0% + + + + align:start position:0% + +such that x minus c is less than delta + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% + + + + align:start position:0% + +f of x minus f of c + + align:start position:0% + + + + align:start position:0% + +it's greater than or equal to epsilon + + align:start position:0% +it's greater than or equal to epsilon + + + align:start position:0% +it's greater than or equal to epsilon +not + + align:start position:0% +not + + + align:start position:0% +not +okay + + align:start position:0% + + + + align:start position:0% + +now + + align:start position:0% +now + + + align:start position:0% +now +this holds for + + align:start position:0% +this holds for + + + align:start position:0% +this holds for +every delta you can find the x and c so + + align:start position:0% +every delta you can find the x and c so + + + align:start position:0% +every delta you can find the x and c so +that x minus c is less than delta so f + + align:start position:0% +that x minus c is less than delta so f + + + align:start position:0% +that x minus c is less than delta so f +of x minus and f of x minus f of c is + + align:start position:0% +of x minus and f of x minus f of c is + + + align:start position:0% +of x minus and f of x minus f of c is +greater than or equal to epsilon naught + + align:start position:0% +greater than or equal to epsilon naught + + + align:start position:0% +greater than or equal to epsilon naught +so let's choose delta to be one over n + + align:start position:0% +so let's choose delta to be one over n + + + align:start position:0% +so let's choose delta to be one over n +for each natural number n + + align:start position:0% + + + + align:start position:0% + +and for all natural numbers n + + align:start position:0% +and for all natural numbers n + + + align:start position:0% +and for all natural numbers n +there exists + + align:start position:0% +there exists + + + align:start position:0% +there exists +xn + + align:start position:0% +xn + + + align:start position:0% +xn +cn and a b + + align:start position:0% +cn and a b + + + align:start position:0% +cn and a b +such that so this is a statement now + + align:start position:0% +such that so this is a statement now + + + align:start position:0% +such that so this is a statement now +with delta equals one over n + + align:start position:0% +with delta equals one over n + + + align:start position:0% +with delta equals one over n +x n minus c n is less than one over n + + align:start position:0% +x n minus c n is less than one over n + + + align:start position:0% +x n minus c n is less than one over n +and + + align:start position:0% + + + + align:start position:0% + +f of x sub n + + align:start position:0% +f of x sub n + + + align:start position:0% +f of x sub n +minus f of + + align:start position:0% +minus f of + + + align:start position:0% +minus f of +c sub n + + align:start position:0% +c sub n + + + align:start position:0% +c sub n +is bigger than or equal to epsilon zero + + align:start position:0% +is bigger than or equal to epsilon zero + + + align:start position:0% +is bigger than or equal to epsilon zero +okay + + align:start position:0% + + + + align:start position:0% + +now + + align:start position:0% +now + + + align:start position:0% +now +i have two sequences um + + align:start position:0% +i have two sequences um + + + align:start position:0% +i have two sequences um +here + + align:start position:0% +here + + + align:start position:0% +here +and + + align:start position:0% +and + + + align:start position:0% +and +they're bounded because they're in this + + align:start position:0% +they're bounded because they're in this + + + align:start position:0% +they're bounded because they're in this +closed and bounded interval + + align:start position:0% +closed and bounded interval + + + align:start position:0% +closed and bounded interval +so i can pass to a subsequence of one of + + align:start position:0% +so i can pass to a subsequence of one of + + + align:start position:0% +so i can pass to a subsequence of one of +them to start + + align:start position:0% +them to start + + + align:start position:0% +them to start +by + + align:start position:0% +by + + + align:start position:0% +by +the bolzano virustras theorem + + align:start position:0% +the bolzano virustras theorem + + + align:start position:0% +the bolzano virustras theorem +not bc horizontal virus truss i think + + align:start position:0% +not bc horizontal virus truss i think + + + align:start position:0% +not bc horizontal virus truss i think +that's + + align:start position:0% +that's + + + align:start position:0% +that's +probably somewhere else in the lecture + + align:start position:0% +probably somewhere else in the lecture + + + align:start position:0% +probably somewhere else in the lecture +or the previous i wrote bz but i meant + + align:start position:0% +or the previous i wrote bz but i meant + + + align:start position:0% +or the previous i wrote bz but i meant +bw + + align:start position:0% +bw + + + align:start position:0% +bw +by bolzano virustras + + align:start position:0% + + + + align:start position:0% + +there exists + + align:start position:0% + + + + align:start position:0% + +a subsequence + + align:start position:0% +a subsequence + + + align:start position:0% +a subsequence +x n sub k + + align:start position:0% + + + + align:start position:0% + +of x sub n + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% +and + + + align:start position:0% +and +x + + align:start position:0% +x + + + align:start position:0% +x +and a b + + align:start position:0% +and a b + + + align:start position:0% +and a b +such that + + align:start position:0% +such that + + + align:start position:0% +such that +limit as k goes to infinity of x of n + + align:start position:0% +limit as k goes to infinity of x of n + + + align:start position:0% +limit as k goes to infinity of x of n +sub k + + align:start position:0% +sub k + + + align:start position:0% +sub k +equals uh + + align:start position:0% +equals uh + + + align:start position:0% +equals uh +x so + + align:start position:0% +x so + + + align:start position:0% +x so +my balzona virustras from any bounded + + align:start position:0% +my balzona virustras from any bounded + + + align:start position:0% +my balzona virustras from any bounded +sequence we can find a convergent + + align:start position:0% +sequence we can find a convergent + + + align:start position:0% +sequence we can find a convergent +subsequence and because this subsequence + + align:start position:0% +subsequence and because this subsequence + + + align:start position:0% +subsequence and because this subsequence +is always between a and b + + align:start position:0% +is always between a and b + + + align:start position:0% +is always between a and b +the limit x will be between a and b all + + align:start position:0% +the limit x will be between a and b all + + + align:start position:0% +the limit x will be between a and b all +right + + align:start position:0% + + + + align:start position:0% + +now + + align:start position:0% +now + + + align:start position:0% +now +if i look at + + align:start position:0% + + + + align:start position:0% + +since + + align:start position:0% + + + + align:start position:0% + +the subsequence c in sub k is + + align:start position:0% + + + + align:start position:0% + +bounded between + + align:start position:0% +bounded between + + + align:start position:0% +bounded between +a and + + align:start position:0% +a and + + + align:start position:0% +a and +b + + align:start position:0% +b + + + align:start position:0% +b +so + + align:start position:0% +so + + + align:start position:0% +so +i have a subsequence of x of n sub k and + + align:start position:0% +i have a subsequence of x of n sub k and + + + align:start position:0% +i have a subsequence of x of n sub k and +i then obtain a subsequence of the c sub + + align:start position:0% +i then obtain a subsequence of the c sub + + + align:start position:0% +i then obtain a subsequence of the c sub +n's okay by just picking these integers + + align:start position:0% +n's okay by just picking these integers + + + align:start position:0% +n's okay by just picking these integers +to be the same + + align:start position:0% +to be the same + + + align:start position:0% +to be the same +all right + + align:start position:0% +all right + + + align:start position:0% +all right +and + + align:start position:0% +and + + + align:start position:0% +and +so now that subsequence is + + align:start position:0% +so now that subsequence is + + + align:start position:0% +so now that subsequence is +of the c sub n that's still uh you know + + align:start position:0% +of the c sub n that's still uh you know + + + align:start position:0% +of the c sub n that's still uh you know +they're all coming from a b so that's + + align:start position:0% +they're all coming from a b so that's + + + align:start position:0% +they're all coming from a b so that's +bounded by a b + + align:start position:0% +bounded by a b + + + align:start position:0% +bounded by a b +so it's bounded so by + + align:start position:0% + + + + align:start position:0% + +bolzano virustras applied now to this + + align:start position:0% +bolzano virustras applied now to this + + + align:start position:0% +bolzano virustras applied now to this +subsequence + + align:start position:0% +subsequence + + + align:start position:0% +subsequence +there exists + + align:start position:0% + + + + align:start position:0% + +a subsequence + + align:start position:0% + + + + align:start position:0% + +c sub n sub k sub j + + align:start position:0% +c sub n sub k sub j + + + align:start position:0% +c sub n sub k sub j +j of + + align:start position:0% +j of + + + align:start position:0% +j of +c sub n sub k + + align:start position:0% +c sub n sub k + + + align:start position:0% +c sub n sub k +okay + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% +and + + + align:start position:0% +and +an element c in a b + + align:start position:0% + + + + align:start position:0% + +such that the limit as + + align:start position:0% +such that the limit as + + + align:start position:0% +such that the limit as +j goes to infinity of c sub n sub k sub + + align:start position:0% +j goes to infinity of c sub n sub k sub + + + align:start position:0% +j goes to infinity of c sub n sub k sub +j + + align:start position:0% +j + + + align:start position:0% +j +equals c okay so + + align:start position:0% +equals c okay so + + + align:start position:0% +equals c okay so +you know i found a subsequence of the x + + align:start position:0% +you know i found a subsequence of the x + + + align:start position:0% +you know i found a subsequence of the x +of n's + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% +and + + + align:start position:0% +and +now i look at kind of a corresponding + + align:start position:0% +now i look at kind of a corresponding + + + align:start position:0% +now i look at kind of a corresponding +subsequence of the c sub n's where now + + align:start position:0% +subsequence of the c sub n's where now + + + align:start position:0% +subsequence of the c sub n's where now +this subsequence the n sub k's + + align:start position:0% +this subsequence the n sub k's + + + align:start position:0% +this subsequence the n sub k's +are + + align:start position:0% +are + + + align:start position:0% +are +coming from the n sub k is chosen for + + align:start position:0% +coming from the n sub k is chosen for + + + align:start position:0% +coming from the n sub k is chosen for +this subsequence + + align:start position:0% +this subsequence + + + align:start position:0% +this subsequence +that's still a bounded sequence so by + + align:start position:0% +that's still a bounded sequence so by + + + align:start position:0% +that's still a bounded sequence so by +bolzano virustrals i can take a + + align:start position:0% +bolzano virustrals i can take a + + + align:start position:0% +bolzano virustrals i can take a +subsequence of that + + align:start position:0% +subsequence of that + + + align:start position:0% +subsequence of that +and an element c + + align:start position:0% +and an element c + + + align:start position:0% +and an element c +so that i have convergence + + align:start position:0% +so that i have convergence + + + align:start position:0% +so that i have convergence +okay + + align:start position:0% + + + + align:start position:0% + +all right + + align:start position:0% +all right + + + align:start position:0% +all right +so now + + align:start position:0% +so now + + + align:start position:0% +so now +let me just uh summarize + + align:start position:0% + + + + align:start position:0% + +in summary + + align:start position:0% + + + + align:start position:0% + +let's call these + + align:start position:0% + + + + align:start position:0% + +so in summary + + align:start position:0% + + + + align:start position:0% + +the sequence is + + align:start position:0% +the sequence is + + + align:start position:0% +the sequence is +x sub n sub k sub j so now this is even + + align:start position:0% +x sub n sub k sub j so now this is even + + + align:start position:0% +x sub n sub k sub j so now this is even +a subsequence of x of n sub k + + align:start position:0% +a subsequence of x of n sub k + + + align:start position:0% +a subsequence of x of n sub k +and c sub n sub k sub j + + align:start position:0% + + + + align:start position:0% + +these are + + align:start position:0% + + + + align:start position:0% + +subsequences of + + align:start position:0% +subsequences of + + + align:start position:0% +subsequences of +the original sequences x of n + + align:start position:0% + + + + align:start position:0% + +and c sub n + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% + + + + align:start position:0% + +there's this x and c + + align:start position:0% +there's this x and c + + + align:start position:0% +there's this x and c +a b + + align:start position:0% +a b + + + align:start position:0% +a b +such that + + align:start position:0% +such that + + + align:start position:0% +such that +the limit + + align:start position:0% +the limit + + + align:start position:0% +the limit +as + + align:start position:0% +as + + + align:start position:0% +as +j goes to infinity of x of n sub j + + align:start position:0% +j goes to infinity of x of n sub j + + + align:start position:0% +j goes to infinity of x of n sub j +equals x + + align:start position:0% +equals x + + + align:start position:0% +equals x +and + + align:start position:0% +and + + + align:start position:0% +and +limit as j goes to infinity of c sub n + + align:start position:0% +limit as j goes to infinity of c sub n + + + align:start position:0% +limit as j goes to infinity of c sub n +sub + + align:start position:0% + + + + align:start position:0% + +k j + + align:start position:0% +k j + + + align:start position:0% +k j +h j equals c + + align:start position:0% +h j equals c + + + align:start position:0% +h j equals c +okay + + align:start position:0% + + + + align:start position:0% + +now i claim x equals c + + align:start position:0% + + + + align:start position:0% + +now + + align:start position:0% +now + + + align:start position:0% +now +um + + align:start position:0% + + + + align:start position:0% + +0 is certainly bigger than or equal to x + + align:start position:0% +0 is certainly bigger than or equal to x + + + align:start position:0% +0 is certainly bigger than or equal to x +of n sub k sub j minus + + align:start position:0% +of n sub k sub j minus + + + align:start position:0% +of n sub k sub j minus +c sub n sub k sub j + + align:start position:0% +c sub n sub k sub j + + + align:start position:0% +c sub n sub k sub j +which is less than or equal to by + + align:start position:0% +which is less than or equal to by + + + align:start position:0% +which is less than or equal to by +how we've defined these sequences + + align:start position:0% +how we've defined these sequences + + + align:start position:0% +how we've defined these sequences +is less than or equal to one over n sub + + align:start position:0% +is less than or equal to one over n sub + + + align:start position:0% +is less than or equal to one over n sub +k sub j + + align:start position:0% + + + + align:start position:0% + +all right + + align:start position:0% +all right + + + align:start position:0% +all right +and as j goes to infinity so first off + + align:start position:0% +and as j goes to infinity so first off + + + align:start position:0% +and as j goes to infinity so first off +uh + + align:start position:0% +uh + + + align:start position:0% +uh +by + + align:start position:0% +by + + + align:start position:0% +by +the definition of uh subsequences + + align:start position:0% +the definition of uh subsequences + + + align:start position:0% +the definition of uh subsequences +um j is always bigger than or equal to n + + align:start position:0% +um j is always bigger than or equal to n + + + align:start position:0% +um j is always bigger than or equal to n +sub case or n sub k sub j is always + + align:start position:0% +sub case or n sub k sub j is always + + + align:start position:0% +sub case or n sub k sub j is always +bigger than or equal to j so this is + + align:start position:0% +bigger than or equal to j so this is + + + align:start position:0% +bigger than or equal to j so this is +always less than or equal to one over j + + align:start position:0% +always less than or equal to one over j + + + align:start position:0% +always less than or equal to one over j +this is just a consequence of how + + align:start position:0% +this is just a consequence of how + + + align:start position:0% +this is just a consequence of how +subsequences are defined okay you always + + align:start position:0% +subsequences are defined okay you always + + + align:start position:0% +subsequences are defined okay you always +have to move to the right after you've + + align:start position:0% +have to move to the right after you've + + + align:start position:0% +have to move to the right after you've +made a choice of + + align:start position:0% +made a choice of + + + align:start position:0% +made a choice of +a + + align:start position:0% +a + + + align:start position:0% +a +entry in the sequence that you're going + + align:start position:0% +entry in the sequence that you're going + + + align:start position:0% +entry in the sequence that you're going +to take as an element of your + + align:start position:0% +to take as an element of your + + + align:start position:0% +to take as an element of your +subsequence + + align:start position:0% +subsequence + + + align:start position:0% +subsequence +so 0 is bounded + + align:start position:0% +so 0 is bounded + + + align:start position:0% +so 0 is bounded +bounds this from below + + align:start position:0% +bounds this from below + + + align:start position:0% +bounds this from below +and it's bounded above by 1 over j which + + align:start position:0% +and it's bounded above by 1 over j which + + + align:start position:0% +and it's bounded above by 1 over j which +converges to 0. so + + align:start position:0% +converges to 0. so + + + align:start position:0% +converges to 0. so +the middle thing has to converge to zero + + align:start position:0% +the middle thing has to converge to zero + + + align:start position:0% +the middle thing has to converge to zero +by the squeeze theorem + + align:start position:0% + + + + align:start position:0% + +but these two things that converges to x + + align:start position:0% +but these two things that converges to x + + + align:start position:0% +but these two things that converges to x +this converges to c + + align:start position:0% + + + + align:start position:0% + +and so + + align:start position:0% +and so + + + align:start position:0% +and so +the absolute value of x minus c equals 0 + + align:start position:0% +the absolute value of x minus c equals 0 + + + align:start position:0% +the absolute value of x minus c equals 0 +and therefore + + align:start position:0% +and therefore + + + align:start position:0% +and therefore +x equals c + + align:start position:0% + + + + align:start position:0% + +now we're almost home free + + align:start position:0% + + + + align:start position:0% + +thus limit + + align:start position:0% +thus limit + + + align:start position:0% +thus limit +as j goes to infinity of x sub n sub k + + align:start position:0% +as j goes to infinity of x sub n sub k + + + align:start position:0% +as j goes to infinity of x sub n sub k +sub j + + align:start position:0% +sub j + + + align:start position:0% +sub j +equals c + + align:start position:0% + + + + align:start position:0% + +and limit as + + align:start position:0% +and limit as + + + align:start position:0% +and limit as +j goes to infinity + + align:start position:0% +j goes to infinity + + + align:start position:0% +j goes to infinity +c sub n sub k sub j + + align:start position:0% +c sub n sub k sub j + + + align:start position:0% +c sub n sub k sub j +equals + + align:start position:0% +equals + + + align:start position:0% +equals +c + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% + + + + align:start position:0% + +all right now where's uh where's the + + align:start position:0% +all right now where's uh where's the + + + align:start position:0% +all right now where's uh where's the +kicker + + align:start position:0% +kicker + + + align:start position:0% +kicker +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +this + + align:start position:0% +this + + + align:start position:0% +this +so these are subsequences of x sub n and + + align:start position:0% +so these are subsequences of x sub n and + + + align:start position:0% +so these are subsequences of x sub n and +c sub n + + align:start position:0% +c sub n + + + align:start position:0% +c sub n +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +but each of those sequences is + + align:start position:0% +but each of those sequences is + + + align:start position:0% +but each of those sequences is +converging to a number c so by the + + align:start position:0% +converging to a number c so by the + + + align:start position:0% +converging to a number c so by the +theorem about continuity + + align:start position:0% + + + + align:start position:0% + +since f is + + align:start position:0% +since f is + + + align:start position:0% +since f is +continuous + + align:start position:0% +continuous + + + align:start position:0% +continuous +at c this implies that 0 + + align:start position:0% +at c this implies that 0 + + + align:start position:0% +at c this implies that 0 +equals the limit as j goes to infinity + + align:start position:0% +equals the limit as j goes to infinity + + + align:start position:0% +equals the limit as j goes to infinity +of + + align:start position:0% +of + + + align:start position:0% +of +f of x sub n sub + + align:start position:0% +f of x sub n sub + + + align:start position:0% +f of x sub n sub +so + + align:start position:0% + + + + align:start position:0% + +write it this way f of c minus f of c + + align:start position:0% +write it this way f of c minus f of c + + + align:start position:0% +write it this way f of c minus f of c +equals + + align:start position:0% +equals + + + align:start position:0% +equals +limit j goes to infinity of + + align:start position:0% +limit j goes to infinity of + + + align:start position:0% +limit j goes to infinity of +f of n sub + + align:start position:0% + + + + align:start position:0% + +n sub + + align:start position:0% +n sub + + + align:start position:0% +n sub +c sub n sub k sub j + + align:start position:0% +c sub n sub k sub j + + + align:start position:0% +c sub n sub k sub j +which is bigger than or equal to epsilon + + align:start position:0% +which is bigger than or equal to epsilon + + + align:start position:0% +which is bigger than or equal to epsilon +zero right all of these are supposed to + + align:start position:0% +zero right all of these are supposed to + + + align:start position:0% +zero right all of these are supposed to +be bigger than or equal to some fixed + + align:start position:0% +be bigger than or equal to some fixed + + + align:start position:0% +be bigger than or equal to some fixed +epsilon zero which is positive + + align:start position:0% + + + + align:start position:0% + +and but we've just shown it's equal to + + align:start position:0% +and but we've just shown it's equal to + + + align:start position:0% +and but we've just shown it's equal to +zero + + align:start position:0% + + + + align:start position:0% + +and that's the contradiction + + align:start position:0% + + + + align:start position:0% + +plus f is + + align:start position:0% +plus f is + + + align:start position:0% +plus f is +uniformly continuous + + align:start position:0% +uniformly continuous + + + align:start position:0% +uniformly continuous +on + + align:start position:0% +on + + + align:start position:0% +on +a b + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +all right so that concludes um + + align:start position:0% +all right so that concludes um + + + align:start position:0% +all right so that concludes um +you know what we'll say about continuity + + align:start position:0% +you know what we'll say about continuity + + + align:start position:0% +you know what we'll say about continuity +and as you'll note kind of going forward + + align:start position:0% +and as you'll note kind of going forward + + + align:start position:0% +and as you'll note kind of going forward +we're going to cover topics faster + + align:start position:0% +we're going to cover topics faster + + + align:start position:0% +we're going to cover topics faster +that's just because we have more + + align:start position:0% +that's just because we have more + + + align:start position:0% +that's just because we have more +machinery to to work with you know at + + align:start position:0% +machinery to to work with you know at + + + align:start position:0% +machinery to to work with you know at +the start it was very slow going just + + align:start position:0% +the start it was very slow going just + + + align:start position:0% +the start it was very slow going just +because + + align:start position:0% +because + + + align:start position:0% +because +one + + align:start position:0% + + + + align:start position:0% + +it's the start of your first proof-based + + align:start position:0% +it's the start of your first proof-based + + + align:start position:0% +it's the start of your first proof-based +class so i'm going to go slow + + align:start position:0% +class so i'm going to go slow + + + align:start position:0% +class so i'm going to go slow +and two we didn't have much to work with + + align:start position:0% +and two we didn't have much to work with + + + align:start position:0% +and two we didn't have much to work with +we just had the real numbers are + + align:start position:0% +we just had the real numbers are + + + align:start position:0% +we just had the real numbers are +an ordered field with the least upper + + align:start position:0% +an ordered field with the least upper + + + align:start position:0% +an ordered field with the least upper +bound property but now we've covered + + align:start position:0% +bound property but now we've covered + + + align:start position:0% +bound property but now we've covered +sequences + + align:start position:0% +sequences + + + align:start position:0% +sequences +continuity we know more and it'll be + + align:start position:0% +continuity we know more and it'll be + + + align:start position:0% +continuity we know more and it'll be +easier to to + + align:start position:0% +easier to to + + + align:start position:0% +easier to to +prove new things and also + + align:start position:0% +prove new things and also + + + align:start position:0% +prove new things and also +you know hopefully familiarity with + + align:start position:0% +you know hopefully familiarity with + + + align:start position:0% +you know hopefully familiarity with +proof is getting with proofs + + align:start position:0% +proof is getting with proofs + + + align:start position:0% +proof is getting with proofs +is getting better so that + + align:start position:0% +is getting better so that + + + align:start position:0% +is getting better so that +my arguments can be a little bit shorter + + align:start position:0% +my arguments can be a little bit shorter + + + align:start position:0% +my arguments can be a little bit shorter +and not so + + align:start position:0% +and not so + + + align:start position:0% +and not so +so involved + + align:start position:0% +so involved + + + align:start position:0% +so involved +so + + align:start position:0% +so + + + align:start position:0% +so +we're moving on to something now + + align:start position:0% +we're moving on to something now + + + align:start position:0% +we're moving on to something now +uh + + align:start position:0% +uh + + + align:start position:0% +uh +this is supposed to be about calculus + + align:start position:0% +this is supposed to be about calculus + + + align:start position:0% +this is supposed to be about calculus +we've covered limits uh continuity the + + align:start position:0% +we've covered limits uh continuity the + + + align:start position:0% +we've covered limits uh continuity the +next uh + + align:start position:0% +next uh + + + align:start position:0% +next uh +big topic + + align:start position:0% +big topic + + + align:start position:0% +big topic +has to be differentiability so + + align:start position:0% + + + + align:start position:0% + +this is a new chapter + + align:start position:0% + + + + align:start position:0% + +about the derivative + + align:start position:0% + + + + align:start position:0% + +so let's um + + align:start position:0% + + + + align:start position:0% + +let me first + + align:start position:0% +let me first + + + align:start position:0% +let me first +give you the precise definition so + + align:start position:0% +give you the precise definition so + + + align:start position:0% +give you the precise definition so +um + + align:start position:0% + + + + align:start position:0% + +first off + + align:start position:0% +first off + + + align:start position:0% +first off +i'll be saying uh + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +let i be + + align:start position:0% + + + + align:start position:0% + +an interval + + align:start position:0% + + + + align:start position:0% + +f goes from i to r + + align:start position:0% + + + + align:start position:0% + +and c an element of i + + align:start position:0% +and c an element of i + + + align:start position:0% +and c an element of i +now when i say an interval i don't mean + + align:start position:0% +now when i say an interval i don't mean + + + align:start position:0% +now when i say an interval i don't mean +it has to be closed and bounded like + + align:start position:0% +it has to be closed and bounded like + + + align:start position:0% +it has to be closed and bounded like +ones we've been working on i don't mean + + align:start position:0% +ones we've been working on i don't mean + + + align:start position:0% +ones we've been working on i don't mean +it has to be open you know it doesn't + + align:start position:0% +it has to be open you know it doesn't + + + align:start position:0% +it has to be open you know it doesn't +have to be a bounded interval like from + + align:start position:0% +have to be a bounded interval like from + + + align:start position:0% +have to be a bounded interval like from +zero to one it could be zero to infinity + + align:start position:0% +zero to one it could be zero to infinity + + + align:start position:0% +zero to one it could be zero to infinity +uh it can include the endpoints except + + align:start position:0% +uh it can include the endpoints except + + + align:start position:0% +uh it can include the endpoints except +of course infinity + + align:start position:0% +of course infinity + + + align:start position:0% +of course infinity +but i think you know what i mean and i + + align:start position:0% +but i think you know what i mean and i + + + align:start position:0% +but i think you know what i mean and i +don't have to write all this out for for + + align:start position:0% +don't have to write all this out for for + + + align:start position:0% +don't have to write all this out for for +what exactly an interval is so let i be + + align:start position:0% +what exactly an interval is so let i be + + + align:start position:0% +what exactly an interval is so let i be +an interval and f be a function from i + + align:start position:0% +an interval and f be a function from i + + + align:start position:0% +an interval and f be a function from i +to r + + align:start position:0% +to r + + + align:start position:0% +to r +and c uh a point of i + + align:start position:0% +and c uh a point of i + + + align:start position:0% +and c uh a point of i +um + + align:start position:0% +um + + + align:start position:0% +um +so + + align:start position:0% +so + + + align:start position:0% +so +first off + + align:start position:0% + + + + align:start position:0% + +you know convince yourselves of this but + + align:start position:0% +you know convince yourselves of this but + + + align:start position:0% +you know convince yourselves of this but +i think this should be pretty clear + + align:start position:0% + + + + align:start position:0% + +for an interval + + align:start position:0% +for an interval + + + align:start position:0% +for an interval +every point in the interval is a cluster + + align:start position:0% +every point in the interval is a cluster + + + align:start position:0% +every point in the interval is a cluster +point of the interval + + align:start position:0% +point of the interval + + + align:start position:0% +point of the interval +okay + + align:start position:0% +okay + + + align:start position:0% +okay +this is not + + align:start position:0% +this is not + + + align:start position:0% +this is not +um + + align:start position:0% +um + + + align:start position:0% +um +you know too difficult to prove but uh + + align:start position:0% +you know too difficult to prove but uh + + + align:start position:0% +you know too difficult to prove but uh +and i will not require you to prove it + + align:start position:0% +and i will not require you to prove it + + + align:start position:0% +and i will not require you to prove it +but i'm just saying this because i'm + + align:start position:0% +but i'm just saying this because i'm + + + align:start position:0% +but i'm just saying this because i'm +about to define a limit at c so + + align:start position:0% +about to define a limit at c so + + + align:start position:0% +about to define a limit at c so +uh it had better be a cluster point of + + align:start position:0% +uh it had better be a cluster point of + + + align:start position:0% +uh it had better be a cluster point of +of um you know a set + + align:start position:0% +of um you know a set + + + align:start position:0% +of um you know a set +containing um + + align:start position:0% +containing um + + + align:start position:0% +containing um +of a set + + align:start position:0% +of a set + + + align:start position:0% +of a set +that this limit is defined using so + + align:start position:0% + + + + align:start position:0% + +of i + + align:start position:0% +of i + + + align:start position:0% +of i +take away c + + align:start position:0% + + + + align:start position:0% + +and if you don't like this statement + + align:start position:0% +and if you don't like this statement + + + align:start position:0% +and if you don't like this statement +just forget i even wrote you know wrote + + align:start position:0% +just forget i even wrote you know wrote + + + align:start position:0% +just forget i even wrote you know wrote +it and we'll continue on + + align:start position:0% + + + + align:start position:0% + +you say f + + align:start position:0% + + + + align:start position:0% + +is differentiable + + align:start position:0% + + + + align:start position:0% + +at c + + align:start position:0% +at c + + + align:start position:0% +at c +so this is the new + + align:start position:0% + + + + align:start position:0% + +bit of terminology + + align:start position:0% + + + + align:start position:0% + +if the limit + + align:start position:0% + + + + align:start position:0% + +limit x goes to c + + align:start position:0% +limit x goes to c + + + align:start position:0% +limit x goes to c +f of x minus + + align:start position:0% +f of x minus + + + align:start position:0% +f of x minus +f of c over x minus c + + align:start position:0% + + + + align:start position:0% + +exists + + align:start position:0% +exists + + + align:start position:0% +exists +okay if this limit exists we say the + + align:start position:0% +okay if this limit exists we say the + + + align:start position:0% +okay if this limit exists we say the +function's differentiable at z + + align:start position:0% +function's differentiable at z + + + align:start position:0% +function's differentiable at z +and + + align:start position:0% + + + + align:start position:0% + +we write + + align:start position:0% +we write + + + align:start position:0% +we write +we use a notation + + align:start position:0% +we use a notation + + + align:start position:0% +we use a notation +f prime f apostrophe c + + align:start position:0% +f prime f apostrophe c + + + align:start position:0% +f prime f apostrophe c +for this limit + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +f is differentiable + + align:start position:0% + + + + align:start position:0% + +every point + + align:start position:0% + + + + align:start position:0% + +of the interval i we get a new function + + align:start position:0% +of the interval i we get a new function + + + align:start position:0% +of the interval i we get a new function +this function f prime of c which we + + align:start position:0% +this function f prime of c which we + + + align:start position:0% +this function f prime of c which we +denote by + + align:start position:0% + + + + align:start position:0% + +we denote + + align:start position:0% + + + + align:start position:0% + +the + + align:start position:0% + + + + align:start position:0% + +function that's the derivative of f as f + + align:start position:0% +function that's the derivative of f as f + + + align:start position:0% +function that's the derivative of f as f +prime or df dx + + align:start position:0% +prime or df dx + + + align:start position:0% +prime or df dx +okay + + align:start position:0% + + + + align:start position:0% + +okay so the simplest guys that are + + align:start position:0% +okay so the simplest guys that are + + + align:start position:0% +okay so the simplest guys that are +differentiable are of course polynomials + + align:start position:0% +differentiable are of course polynomials + + + align:start position:0% +differentiable are of course polynomials +i think this is one of the first things + + align:start position:0% +i think this is one of the first things + + + align:start position:0% +i think this is one of the first things +you learned back in calculus um + + align:start position:0% +you learned back in calculus um + + + align:start position:0% +you learned back in calculus um +and + + align:start position:0% + + + + align:start position:0% + +you know + + align:start position:0% +you know + + + align:start position:0% +you know +i'm not going to go through what this is + + align:start position:0% +i'm not going to go through what this is + + + align:start position:0% +i'm not going to go through what this is +supposed to represent you know this from + + align:start position:0% +supposed to represent you know this from + + + align:start position:0% +supposed to represent you know this from +calculus + + align:start position:0% +calculus + + + align:start position:0% +calculus +the best way to say what this number + + align:start position:0% +the best way to say what this number + + + align:start position:0% +the best way to say what this number +represents is the instantaneous rate of + + align:start position:0% +represents is the instantaneous rate of + + + align:start position:0% +represents is the instantaneous rate of +change of the function f at this point + + align:start position:0% +change of the function f at this point + + + align:start position:0% +change of the function f at this point +how is f + + align:start position:0% +how is f + + + align:start position:0% +how is f +changing at that point + + align:start position:0% +changing at that point + + + align:start position:0% +changing at that point +in the sense of increasing decreasing + + align:start position:0% +in the sense of increasing decreasing + + + align:start position:0% +in the sense of increasing decreasing +and so on + + align:start position:0% +and so on + + + align:start position:0% +and so on +all right + + align:start position:0% + + + + align:start position:0% + +or you if you like you interpret this as + + align:start position:0% +or you if you like you interpret this as + + + align:start position:0% +or you if you like you interpret this as +being the slope of the line that is + + align:start position:0% +being the slope of the line that is + + + align:start position:0% +being the slope of the line that is +perfectly tangent to the curve + + align:start position:0% +perfectly tangent to the curve + + + align:start position:0% +perfectly tangent to the curve +uh to the graph of the function f but uh + + align:start position:0% +uh to the graph of the function f but uh + + + align:start position:0% +uh to the graph of the function f but uh +um + + align:start position:0% +um + + + align:start position:0% +um +you know what does that mean to be + + align:start position:0% +you know what does that mean to be + + + align:start position:0% +you know what does that mean to be +tangent to the graph of a function you + + align:start position:0% +tangent to the graph of a function you + + + align:start position:0% +tangent to the graph of a function you +know so that takes a bit of explaining + + align:start position:0% +know so that takes a bit of explaining + + + align:start position:0% +know so that takes a bit of explaining +so i'm not going to get into what the + + align:start position:0% +so i'm not going to get into what the + + + align:start position:0% +so i'm not going to get into what the +actual + + align:start position:0% + + + + align:start position:0% + +interpretation of this number is + + align:start position:0% +interpretation of this number is + + + align:start position:0% +interpretation of this number is +i think you have a pretty good idea of + + align:start position:0% +i think you have a pretty good idea of + + + align:start position:0% +i think you have a pretty good idea of +what that is we're just going to start + + align:start position:0% +what that is we're just going to start + + + align:start position:0% +what that is we're just going to start +proving some properties of it + + align:start position:0% +proving some properties of it + + + align:start position:0% +proving some properties of it +so + + align:start position:0% +so + + + align:start position:0% +so +the simplest example of a function which + + align:start position:0% +the simplest example of a function which + + + align:start position:0% +the simplest example of a function which +is differentiable + + align:start position:0% + + + + align:start position:0% + +is that of a monomial + + align:start position:0% +is that of a monomial + + + align:start position:0% +is that of a monomial +so + + align:start position:0% + + + + align:start position:0% + +f of x equals + + align:start position:0% +f of x equals + + + align:start position:0% +f of x equals +x to the n + + align:start position:0% +x to the n + + + align:start position:0% +x to the n +let's put let's put even a number in + + align:start position:0% +let's put let's put even a number in + + + align:start position:0% +let's put let's put even a number in +there + + align:start position:0% +there + + + align:start position:0% +there +so let uh + + align:start position:0% +so let uh + + + align:start position:0% +so let uh +let's write it this way + + align:start position:0% +let's write it this way + + + align:start position:0% +let's write it this way +but alpha being r + + align:start position:0% +but alpha being r + + + align:start position:0% +but alpha being r +and b a natural number + + align:start position:0% +and b a natural number + + + align:start position:0% +and b a natural number +zero + + align:start position:0% + + + + align:start position:0% + +then + + align:start position:0% + + + + align:start position:0% + +function f of x equals alpha times x to + + align:start position:0% +function f of x equals alpha times x to + + + align:start position:0% +function f of x equals alpha times x to +the n + + align:start position:0% + + + + align:start position:0% + +is + + align:start position:0% +is + + + align:start position:0% +is +differentiable um + + align:start position:0% + + + + align:start position:0% + +so i should have said here as well if a + + align:start position:0% +so i should have said here as well if a + + + align:start position:0% +so i should have said here as well if a +function is differentiable at every + + align:start position:0% +function is differentiable at every + + + align:start position:0% +function is differentiable at every +point where it's defined + + align:start position:0% +point where it's defined + + + align:start position:0% +point where it's defined +uh + + align:start position:0% +uh + + + align:start position:0% +uh +or if a function is differentiable at + + align:start position:0% +or if a function is differentiable at + + + align:start position:0% +or if a function is differentiable at +every point in its domain i then we just + + align:start position:0% +every point in its domain i then we just + + + align:start position:0% +every point in its domain i then we just +say the function's differentiable + + align:start position:0% +say the function's differentiable + + + align:start position:0% +say the function's differentiable +so then this function this monomial is + + align:start position:0% +so then this function this monomial is + + + align:start position:0% +so then this function this monomial is +differentiable and + + align:start position:0% + + + + align:start position:0% + +for all c f prime of c equals + + align:start position:0% +for all c f prime of c equals + + + align:start position:0% +for all c f prime of c equals +n times alpha x the n minus 1. + + align:start position:0% +n times alpha x the n minus 1. + + + align:start position:0% +n times alpha x the n minus 1. +okay + + align:start position:0% +okay + + + align:start position:0% +okay +c + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so let's give a proof of that + + align:start position:0% +so let's give a proof of that + + + align:start position:0% +so let's give a proof of that +and we'll use + + align:start position:0% +and we'll use + + + align:start position:0% +and we'll use +this + + align:start position:0% +this + + + align:start position:0% +this +kind of simple formula + + align:start position:0% + + + + align:start position:0% + +so let's take a look at + + align:start position:0% + + + + align:start position:0% + +x minus c times this kind of + + align:start position:0% +x minus c times this kind of + + + align:start position:0% +x minus c times this kind of +weird looking sum to + + align:start position:0% +weird looking sum to + + + align:start position:0% +weird looking sum to +x + + align:start position:0% +x + + + align:start position:0% +x +n minus 1 minus j + + align:start position:0% +n minus 1 minus j + + + align:start position:0% +n minus 1 minus j +c to the + + align:start position:0% +c to the + + + align:start position:0% +c to the +j + + align:start position:0% + + + + align:start position:0% + +so this is equal to + + align:start position:0% +so this is equal to + + + align:start position:0% +so this is equal to +multiply the x through i get sum from + + align:start position:0% +multiply the x through i get sum from + + + align:start position:0% +multiply the x through i get sum from +j equals 0 to + + align:start position:0% +j equals 0 to + + + align:start position:0% +j equals 0 to +n minus 1 + + align:start position:0% +n minus 1 + + + align:start position:0% +n minus 1 +x to the + + align:start position:0% +x to the + + + align:start position:0% +x to the +n minus j + + align:start position:0% +n minus j + + + align:start position:0% +n minus j +c to the j minus + + align:start position:0% +c to the j minus + + + align:start position:0% +c to the j minus +and i'm not going to use j again in the + + align:start position:0% +and i'm not going to use j again in the + + + align:start position:0% +and i'm not going to use j again in the +sum when i carry this c through i'm + + align:start position:0% +sum when i carry this c through i'm + + + align:start position:0% +sum when i carry this c through i'm +going to use l + + align:start position:0% +going to use l + + + align:start position:0% +going to use l +sum from l equals 0 + + align:start position:0% +sum from l equals 0 + + + align:start position:0% +sum from l equals 0 +to + + align:start position:0% +to + + + align:start position:0% +to +n minus 1 + + align:start position:0% +n minus 1 + + + align:start position:0% +n minus 1 +x to the + + align:start position:0% +x to the + + + align:start position:0% +x to the +n minus i'll put it this way j plus 1 + + align:start position:0% +n minus i'll put it this way j plus 1 + + + align:start position:0% +n minus i'll put it this way j plus 1 +c to the j plus 1 + + align:start position:0% +c to the j plus 1 + + + align:start position:0% +c to the j plus 1 +or + + align:start position:0% +or + + + align:start position:0% +or +l + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and now i'm going to make a change of + + align:start position:0% +and now i'm going to make a change of + + + align:start position:0% +and now i'm going to make a change of +variables in the second sum + + align:start position:0% +variables in the second sum + + + align:start position:0% +variables in the second sum +and let j equals l plus 1. + + align:start position:0% +and let j equals l plus 1. + + + align:start position:0% +and let j equals l plus 1. +okay + + align:start position:0% + + + + align:start position:0% + +so in that case when l equals 0 j starts + + align:start position:0% +so in that case when l equals 0 j starts + + + align:start position:0% +so in that case when l equals 0 j starts +at 1 + + align:start position:0% +at 1 + + + align:start position:0% +at 1 +when l hits n minus 1 j equals n so this + + align:start position:0% +when l hits n minus 1 j equals n so this + + + align:start position:0% +when l hits n minus 1 j equals n so this +equals the sum from j equals 0 + + align:start position:0% +equals the sum from j equals 0 + + + align:start position:0% +equals the sum from j equals 0 +n minus 1 x n minus j c to the j minus + + align:start position:0% +n minus 1 x n minus j c to the j minus + + + align:start position:0% +n minus 1 x n minus j c to the j minus +sum + + align:start position:0% +sum + + + align:start position:0% +sum +j equals + + align:start position:0% +j equals + + + align:start position:0% +j equals + + align:start position:0% + + + align:start position:0% +to n + + align:start position:0% +to n + + + align:start position:0% +to n +x + + align:start position:0% +x + + + align:start position:0% +x +n minus j c to the j + + align:start position:0% +n minus j c to the j + + + align:start position:0% +n minus j c to the j +so it's the same + + align:start position:0% +so it's the same + + + align:start position:0% +so it's the same +terms in the sum except starting at + + align:start position:0% +terms in the sum except starting at + + + align:start position:0% +terms in the sum except starting at +different places so what doesn't get + + align:start position:0% +different places so what doesn't get + + + align:start position:0% +different places so what doesn't get +killed here is the j equals 0 term + + align:start position:0% +killed here is the j equals 0 term + + + align:start position:0% +killed here is the j equals 0 term +because this one starts at j equals 1 + + align:start position:0% +because this one starts at j equals 1 + + + align:start position:0% +because this one starts at j equals 1 +this one ends at n + + align:start position:0% +this one ends at n + + + align:start position:0% +this one ends at n +and so it kills the n minus 1 term so + + align:start position:0% +and so it kills the n minus 1 term so + + + align:start position:0% +and so it kills the n minus 1 term so +the only thing that survives from this + + align:start position:0% +the only thing that survives from this + + + align:start position:0% +the only thing that survives from this +sum is the j equals 0 term x to the n + + align:start position:0% +sum is the j equals 0 term x to the n + + + align:start position:0% +sum is the j equals 0 term x to the n +minus 0 c to the 0 minus + + align:start position:0% + + + + align:start position:0% + +and now from here + + align:start position:0% +and now from here + + + align:start position:0% +and now from here +everything gets killed except the n term + + align:start position:0% +everything gets killed except the n term + + + align:start position:0% +everything gets killed except the n term +so x to the n minus n c to the n + + align:start position:0% +so x to the n minus n c to the n + + + align:start position:0% +so x to the n minus n c to the n +equals x to the n minus c to the + + align:start position:0% +equals x to the n minus c to the + + + align:start position:0% +equals x to the n minus c to the +right so + + align:start position:0% + + + + align:start position:0% + +this + + align:start position:0% +this + + + align:start position:0% +this +is therefore equal to + + align:start position:0% +is therefore equal to + + + align:start position:0% +is therefore equal to +this okay + + align:start position:0% +this okay + + + align:start position:0% +this okay +so we use this to compute this limit + + align:start position:0% +so we use this to compute this limit + + + align:start position:0% +so we use this to compute this limit +so then + + align:start position:0% +so then + + + align:start position:0% +so then +f prime of c is equal to the limit + + align:start position:0% +f prime of c is equal to the limit + + + align:start position:0% +f prime of c is equal to the limit +as x goes to c + + align:start position:0% +as x goes to c + + + align:start position:0% +as x goes to c +of x to the n + + align:start position:0% +of x to the n + + + align:start position:0% +of x to the n +alpha times x to the n times alpha times + + align:start position:0% +alpha times x to the n times alpha times + + + align:start position:0% +alpha times x to the n times alpha times +c to the n + + align:start position:0% +c to the n + + + align:start position:0% +c to the n +where x minus c now alpha is just a + + align:start position:0% +where x minus c now alpha is just a + + + align:start position:0% +where x minus c now alpha is just a +number it can pop out + + align:start position:0% +number it can pop out + + + align:start position:0% +number it can pop out +x to the n minus c to the n divided by x + + align:start position:0% +x to the n minus c to the n divided by x + + + align:start position:0% +x to the n minus c to the n divided by x +minus c is this thing divided by x minus + + align:start position:0% +minus c is this thing divided by x minus + + + align:start position:0% +minus c is this thing divided by x minus +c so this is equal to alpha + + align:start position:0% +c so this is equal to alpha + + + align:start position:0% +c so this is equal to alpha +times the limit as x goes to c + + align:start position:0% +times the limit as x goes to c + + + align:start position:0% +times the limit as x goes to c +of sum from + + align:start position:0% +of sum from + + + align:start position:0% +of sum from +j equals 0 + + align:start position:0% +j equals 0 + + + align:start position:0% +j equals 0 +to n minus 1 + + align:start position:0% +to n minus 1 + + + align:start position:0% +to n minus 1 +x to the n minus 1 minus j + + align:start position:0% +x to the n minus 1 minus j + + + align:start position:0% +x to the n minus 1 minus j +c to the j + + align:start position:0% +c to the j + + + align:start position:0% +c to the j +now this is just a polynomial in x + + align:start position:0% +now this is just a polynomial in x + + + align:start position:0% +now this is just a polynomial in x +okay polynomials are continuous + + align:start position:0% +okay polynomials are continuous + + + align:start position:0% +okay polynomials are continuous +functions so the limit as x goes to c is + + align:start position:0% +functions so the limit as x goes to c is + + + align:start position:0% +functions so the limit as x goes to c is +just you plug in c to x and so this + + align:start position:0% +just you plug in c to x and so this + + + align:start position:0% +just you plug in c to x and so this +equals alpha + + align:start position:0% +equals alpha + + + align:start position:0% +equals alpha +times sum from j equals 0 to n minus 1. + + align:start position:0% +times sum from j equals 0 to n minus 1. + + + align:start position:0% +times sum from j equals 0 to n minus 1. +c to the n minus 1 + + align:start position:0% +c to the n minus 1 + + + align:start position:0% +c to the n minus 1 +minus j times j equals + + align:start position:0% +minus j times j equals + + + align:start position:0% +minus j times j equals +so c to the n minus 1 minus j times c to + + align:start position:0% +so c to the n minus 1 minus j times c to + + + align:start position:0% +so c to the n minus 1 minus j times c to +the j gives me c to the n minus 1. + + align:start position:0% +the j gives me c to the n minus 1. + + + align:start position:0% +the j gives me c to the n minus 1. +i'm summing in j + + align:start position:0% +i'm summing in j + + + align:start position:0% +i'm summing in j +there's no j here so that just pops out + + align:start position:0% + + + + align:start position:0% + +times the sum + + align:start position:0% +times the sum + + + align:start position:0% +times the sum +j equals 0 + + align:start position:0% +j equals 0 + + + align:start position:0% +j equals 0 +n minus 1 + + align:start position:0% +n minus 1 + + + align:start position:0% +n minus 1 +and that's just there's n of d + + align:start position:0% +and that's just there's n of d + + + align:start position:0% +and that's just there's n of d +times 1 so this is just n + + align:start position:0% + + + + align:start position:0% + +and that's the proof + + align:start position:0% +and that's the proof + + + align:start position:0% +and that's the proof +okay so i'm sure you saw that at some + + align:start position:0% +okay so i'm sure you saw that at some + + + align:start position:0% +okay so i'm sure you saw that at some +point + + align:start position:0% + + + + align:start position:0% + +next time we'll continue with + + align:start position:0% +next time we'll continue with + + + align:start position:0% +next time we'll continue with +we'll give an example of a function + + align:start position:0% +we'll give an example of a function + + + align:start position:0% +we'll give an example of a function +which is not differentiable at a point + + align:start position:0% +which is not differentiable at a point + + + align:start position:0% +which is not differentiable at a point +of course + + align:start position:0% +of course + + + align:start position:0% +of course +i think you probably already know this f + + align:start position:0% +i think you probably already know this f + + + align:start position:0% +i think you probably already know this f +of x equals the absolute value of x + + align:start position:0% +of x equals the absolute value of x + + + align:start position:0% +of x equals the absolute value of x +if there's time at some point + + align:start position:0% +if there's time at some point + + + align:start position:0% +if there's time at some point +i'll go over an example of a function + + align:start position:0% +i'll go over an example of a function + + + align:start position:0% +i'll go over an example of a function +which + + align:start position:0% + + + + align:start position:0% + +was very surprising to people at one + + align:start position:0% +was very surprising to people at one + + + align:start position:0% +was very surprising to people at one +point so now that we have + + align:start position:0% +point so now that we have + + + align:start position:0% +point so now that we have +differentiability and continuity on the + + align:start position:0% +differentiability and continuity on the + + + align:start position:0% +differentiability and continuity on the +board + + align:start position:0% +board + + + align:start position:0% +board +for a long time + + align:start position:0% +for a long time + + + align:start position:0% +for a long time +some long since dead people + + align:start position:0% +some long since dead people + + + align:start position:0% +some long since dead people +believed that if you have a continuous + + align:start position:0% +believed that if you have a continuous + + + align:start position:0% +believed that if you have a continuous +function + + align:start position:0% + + + + align:start position:0% + +any continuous function then there has + + align:start position:0% +any continuous function then there has + + + align:start position:0% +any continuous function then there has +to be at least one point where it's + + align:start position:0% +to be at least one point where it's + + + align:start position:0% +to be at least one point where it's +differentiable + + align:start position:0% +differentiable + + + align:start position:0% +differentiable +okay + + align:start position:0% +okay + + + align:start position:0% +okay +there must be at least one point where + + align:start position:0% +there must be at least one point where + + + align:start position:0% +there must be at least one point where +it's differentiable + + align:start position:0% +it's differentiable + + + align:start position:0% +it's differentiable +and people tried to prove that for a + + align:start position:0% +and people tried to prove that for a + + + align:start position:0% +and people tried to prove that for a +long time and they couldn't because it's + + align:start position:0% +long time and they couldn't because it's + + + align:start position:0% +long time and they couldn't because it's +false + + align:start position:0% +false + + + align:start position:0% +false +virus ross who is again kind of the + + align:start position:0% +virus ross who is again kind of the + + + align:start position:0% +virus ross who is again kind of the +godfather of everything we're doing + + align:start position:0% +godfather of everything we're doing + + + align:start position:0% +godfather of everything we're doing +came up with a + + align:start position:0% +came up with a + + + align:start position:0% +came up with a +whole class of examples of functions + + align:start position:0% +whole class of examples of functions + + + align:start position:0% +whole class of examples of functions +that are continuous + + align:start position:0% +that are continuous + + + align:start position:0% +that are continuous +but are differentiable nowhere okay + + align:start position:0% +but are differentiable nowhere okay + + + align:start position:0% +but are differentiable nowhere okay +they're not differentiable at a single + + align:start position:0% +they're not differentiable at a single + + + align:start position:0% +they're not differentiable at a single +point + + align:start position:0% +point + + + align:start position:0% +point +all right + + align:start position:0% +all right + + + align:start position:0% +all right +and + + align:start position:0% +and + + + align:start position:0% +and +perhaps depending on time + + align:start position:0% +perhaps depending on time + + + align:start position:0% +perhaps depending on time +uh we'll go over this example + + align:start position:0% +uh we'll go over this example + + + align:start position:0% +uh we'll go over this example +and + + align:start position:0% +and + + + align:start position:0% +and +i think i'll stop there + + align:start position:0% + + + + align:start position:0% + +you \ No newline at end of file diff --git a/fmx5Yj95sgQ.txt b/fmx5Yj95sgQ.txt new file mode 100644 index 0000000000000000000000000000000000000000..4882bf8927bdf7cc8101550de08e695c165e8414 --- /dev/null +++ b/fmx5Yj95sgQ.txt @@ -0,0 +1,5651 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT OpenCourseWare continue to + + align:start position:0% +will help MIT OpenCourseWare continue to + + + align:start position:0% +will help MIT OpenCourseWare continue to +offer high quality educational resources + + align:start position:0% +offer high quality educational resources + + + align:start position:0% +offer high quality educational resources +for free + + align:start position:0% +for free + + + align:start position:0% +for free +to make a donation or view additional + + align:start position:0% +to make a donation or view additional + + + align:start position:0% +to make a donation or view additional +materials from hundreds of MIT courses + + align:start position:0% +materials from hundreds of MIT courses + + + align:start position:0% +materials from hundreds of MIT courses +visit MIT opencourseware at ocw.mit.edu + + align:start position:0% +visit MIT opencourseware at ocw.mit.edu + + + align:start position:0% +visit MIT opencourseware at ocw.mit.edu +now why are we interested in sleep so we + + align:start position:0% +now why are we interested in sleep so we + + + align:start position:0% +now why are we interested in sleep so we +kind of think about this two modes + + align:start position:0% +kind of think about this two modes + + + align:start position:0% +kind of think about this two modes +online mode and offline mode the online + + align:start position:0% +online mode and offline mode the online + + + align:start position:0% +online mode and offline mode the online +mode you're taking information in the + + align:start position:0% +mode you're taking information in the + + + align:start position:0% +mode you're taking information in the +offline mode you're going back and + + align:start position:0% +offline mode you're going back and + + + align:start position:0% +offline mode you're going back and +evaluating information what's the + + align:start position:0% +evaluating information what's the + + + align:start position:0% +evaluating information what's the +purpose of evaluating information that + + align:start position:0% +purpose of evaluating information that + + + align:start position:0% +purpose of evaluating information that +you've taken in well if we think about + + align:start position:0% +you've taken in well if we think about + + + align:start position:0% +you've taken in well if we think about +the general problem that's being solved + + align:start position:0% +the general problem that's being solved + + + align:start position:0% +the general problem that's being solved +the problem of intelligence problem of + + align:start position:0% +the problem of intelligence problem of + + + align:start position:0% +the problem of intelligence problem of +intelligence is trying to is trying to + + align:start position:0% +intelligence is trying to is trying to + + + align:start position:0% +intelligence is trying to is trying to +understand and infer these sort of deep + + align:start position:0% +understand and infer these sort of deep + + + align:start position:0% +understand and infer these sort of deep +generalizable relationships rules you're + + align:start position:0% +generalizable relationships rules you're + + + align:start position:0% +generalizable relationships rules you're +trying to expect rules from instances + + align:start position:0% +trying to expect rules from instances + + + align:start position:0% +trying to expect rules from instances +and you'd like those rules to be Jenna's + + align:start position:0% +and you'd like those rules to be Jenna's + + + align:start position:0% +and you'd like those rules to be Jenna's +generally applicable as possible and in + + align:start position:0% +generally applicable as possible and in + + + align:start position:0% +generally applicable as possible and in +order to do that presumably one has to + + align:start position:0% +order to do that presumably one has to + + + align:start position:0% +order to do that presumably one has to +go back and evaluate the many individual + + align:start position:0% +go back and evaluate the many individual + + + align:start position:0% +go back and evaluate the many individual +instances to try to extract some kind of + + align:start position:0% +instances to try to extract some kind of + + + align:start position:0% +instances to try to extract some kind of +statistical regularity and then perhaps + + align:start position:0% +statistical regularity and then perhaps + + + align:start position:0% +statistical regularity and then perhaps +evaluate models that you have + + align:start position:0% +evaluate models that you have + + + align:start position:0% +evaluate models that you have +constructed in terms of their + + align:start position:0% +constructed in terms of their + + + align:start position:0% +constructed in terms of their +consistency with individual instances + + align:start position:0% +consistency with individual instances + + + align:start position:0% +consistency with individual instances +that you've already collected or perhaps + + align:start position:0% +that you've already collected or perhaps + + + align:start position:0% +that you've already collected or perhaps +future instances that that haven't yet + + align:start position:0% +future instances that that haven't yet + + + align:start position:0% +future instances that that haven't yet +play so you've got you get the you have + + align:start position:0% +play so you've got you get the you have + + + align:start position:0% +play so you've got you get the you have +the some of the raw material you bit a + + align:start position:0% +the some of the raw material you bit a + + + align:start position:0% +the some of the raw material you bit a +little model and then you continually + + align:start position:0% +little model and then you continually + + + align:start position:0% +little model and then you continually +test that model against new information + + align:start position:0% +test that model against new information + + + align:start position:0% +test that model against new information +that comes in and the question is when + + align:start position:0% +that comes in and the question is when + + + align:start position:0% +that comes in and the question is when +can you do that now you could do that + + align:start position:0% +can you do that now you could do that + + + align:start position:0% +can you do that now you could do that +when you're out and about in the world + + align:start position:0% +when you're out and about in the world + + + align:start position:0% +when you're out and about in the world +and well as as you as you saw and read + + align:start position:0% +and well as as you as you saw and read + + + align:start position:0% +and well as as you as you saw and read +in that paper when animals are sitting + + align:start position:0% +in that paper when animals are sitting + + + align:start position:0% +in that paper when animals are sitting +quietly they very quickly can switch + + align:start position:0% +quietly they very quickly can switch + + + align:start position:0% +quietly they very quickly can switch +into this kind of offline mode that + + align:start position:0% +into this kind of offline mode that + + + align:start position:0% +into this kind of offline mode that +looks a lot like sleep in fact electro + + align:start position:0% +looks a lot like sleep in fact electro + + + align:start position:0% +looks a lot like sleep in fact electro +physiologically sleep and quiet + + align:start position:0% +physiologically sleep and quiet + + + align:start position:0% +physiologically sleep and quiet +wakefulness and the hippocampus are + + align:start position:0% +wakefulness and the hippocampus are + + + align:start position:0% +wakefulness and the hippocampus are +nearly indistinguishable it's the same + + align:start position:0% +nearly indistinguishable it's the same + + + align:start position:0% +nearly indistinguishable it's the same +kind of offline mode it says ok when + + align:start position:0% +kind of offline mode it says ok when + + + align:start position:0% +kind of offline mode it says ok when +you're not and you know I'm not using + + align:start position:0% +you're not and you know I'm not using + + + align:start position:0% +you're not and you know I'm not using +this if the camp is not being used + + align:start position:0% +this if the camp is not being used + + + align:start position:0% +this if the camp is not being used +taking new information is in I quickly + + align:start position:0% +taking new information is in I quickly + + + align:start position:0% +taking new information is in I quickly +switch into this offline evaluation road + + align:start position:0% +switch into this offline evaluation road + + + align:start position:0% +switch into this offline evaluation road +but during sleep I no longer have the + + align:start position:0% +but during sleep I no longer have the + + + align:start position:0% +but during sleep I no longer have the +constraint of having to direct behavior + + align:start position:0% +constraint of having to direct behavior + + + align:start position:0% +constraint of having to direct behavior +behavior shut off inputs are shut off + + align:start position:0% +behavior shut off inputs are shut off + + + align:start position:0% +behavior shut off inputs are shut off +and now I can switch into this purely + + align:start position:0% +and now I can switch into this purely + + + align:start position:0% +and now I can switch into this purely +interest but internal introspective mode + + align:start position:0% +interest but internal introspective mode + + + align:start position:0% +interest but internal introspective mode +so what goes on during sleep + + align:start position:0% +so what goes on during sleep + + + align:start position:0% +so what goes on during sleep +in the simple experiment and we'll just + + align:start position:0% +in the simple experiment and we'll just + + + align:start position:0% +in the simple experiment and we'll just +we look at the activity when the animal + + align:start position:0% +we look at the activity when the animal + + + align:start position:0% +we look at the activity when the animal +is performing behavioral tasks and then + + align:start position:0% +is performing behavioral tasks and then + + + align:start position:0% +is performing behavioral tasks and then +we examine activity during sleep both + + align:start position:0% +we examine activity during sleep both + + + align:start position:0% +we examine activity during sleep both +before and after and ask is there + + align:start position:0% +before and after and ask is there + + + align:start position:0% +before and after and ask is there +anything about behavioral experience + + align:start position:0% +anything about behavioral experience + + + align:start position:0% +anything about behavioral experience +that changes activity during sleep and + + align:start position:0% +that changes activity during sleep and + + + align:start position:0% +that changes activity during sleep and +what we found was that if you look at + + align:start position:0% +what we found was that if you look at + + + align:start position:0% +what we found was that if you look at +activity during behavior and what you + + align:start position:0% +activity during behavior and what you + + + align:start position:0% +activity during behavior and what you +think about these spatial sequences + + align:start position:0% +think about these spatial sequences + + + align:start position:0% +think about these spatial sequences +being expressed and you look during + + align:start position:0% +being expressed and you look during + + + align:start position:0% +being expressed and you look during +sleep afterward you find that the + + align:start position:0% +sleep afterward you find that the + + + align:start position:0% +sleep afterward you find that the +spatial sequences are expressed again so + + align:start position:0% +spatial sequences are expressed again so + + + align:start position:0% +spatial sequences are expressed again so +the hippocampus replays the firing of + + align:start position:0% +the hippocampus replays the firing of + + + align:start position:0% +the hippocampus replays the firing of +these cell sequences but if but it + + align:start position:0% +these cell sequences but if but it + + + align:start position:0% +these cell sequences but if but it +replays the firing of these cell + + align:start position:0% +replays the firing of these cell + + + align:start position:0% +replays the firing of these cell +sequences at a timescale that appears to + + align:start position:0% +sequences at a timescale that appears to + + + align:start position:0% +sequences at a timescale that appears to +be compressed relative to the behavioral + + align:start position:0% +be compressed relative to the behavioral + + + align:start position:0% +be compressed relative to the behavioral +timescale so these are 8 play cells + + align:start position:0% +timescale so these are 8 play cells + + + align:start position:0% +timescale so these are 8 play cells +animals were walking from left to right + + align:start position:0% +animals were walking from left to right + + + align:start position:0% +animals were walking from left to right +the ticks indicate that's the location + + align:start position:0% +the ticks indicate that's the location + + + align:start position:0% +the ticks indicate that's the location +of the peak so these play cells will + + align:start position:0% +of the peak so these play cells will + + + align:start position:0% +of the peak so these play cells will +fire 1 1 through 8 as the animal moves + + align:start position:0% +fire 1 1 through 8 as the animal moves + + + align:start position:0% +fire 1 1 through 8 as the animal moves +along the track over about 5 seconds + + align:start position:0% +along the track over about 5 seconds + + + align:start position:0% +along the track over about 5 seconds +that's how long it takes animal walk + + align:start position:0% +that's how long it takes animal walk + + + align:start position:0% +that's how long it takes animal walk +from left to right the same sequence of + + align:start position:0% +from left to right the same sequence of + + + align:start position:0% +from left to right the same sequence of +1 2 3 4 5 6 7 8 + + align:start position:0% +1 2 3 4 5 6 7 8 + + + align:start position:0% +1 2 3 4 5 6 7 8 +gets replayed during sleep but now over + + align:start position:0% +gets replayed during sleep but now over + + + align:start position:0% +gets replayed during sleep but now over +about 150 milliseconds same sequence so + + align:start position:0% +about 150 milliseconds same sequence so + + + align:start position:0% +about 150 milliseconds same sequence so +it's you're preserving time order not + + align:start position:0% +it's you're preserving time order not + + + align:start position:0% +it's you're preserving time order not +absolute time and that when you ask when + + align:start position:0% +absolute time and that when you ask when + + + align:start position:0% +absolute time and that when you ask when +these sequences are expressed what's + + align:start position:0% +these sequences are expressed what's + + + align:start position:0% +these sequences are expressed what's +going on in the local field potential + + align:start position:0% +going on in the local field potential + + + align:start position:0% +going on in the local field potential +these oscillations and this is where you + + align:start position:0% +these oscillations and this is where you + + + align:start position:0% +these oscillations and this is where you +find these sharp wave ripple events this + + align:start position:0% +find these sharp wave ripple events this + + + align:start position:0% +find these sharp wave ripple events this +is this ripple this is this ripple like + + align:start position:0% +is this ripple this is this ripple like + + + align:start position:0% +is this ripple this is this ripple like +event that I was describing to you so + + align:start position:0% +event that I was describing to you so + + + align:start position:0% +event that I was describing to you so +these sharp wave ripples are when these + + align:start position:0% +these sharp wave ripples are when these + + + align:start position:0% +these sharp wave ripples are when these +apparently compressed sequences are + + align:start position:0% +apparently compressed sequences are + + + align:start position:0% +apparently compressed sequences are +being expressed I can point out that a + + align:start position:0% +being expressed I can point out that a + + + align:start position:0% +being expressed I can point out that a +simple model for these sharp wave ripple + + align:start position:0% +simple model for these sharp wave ripple + + + align:start position:0% +simple model for these sharp wave ripple +reactivated sequences is the same model + + align:start position:0% +reactivated sequences is the same model + + + align:start position:0% +reactivated sequences is the same model +that's used that I like to use to + + align:start position:0% +that's used that I like to use to + + + align:start position:0% +that's used that I like to use to +explain phase procession during the fête + + align:start position:0% +explain phase procession during the fête + + + align:start position:0% +explain phase procession during the fête +oscillation that is I give it an input I + + align:start position:0% +oscillation that is I give it an input I + + + align:start position:0% +oscillation that is I give it an input I +sweep inhibition from high to low such + + align:start position:0% +sweep inhibition from high to low such + + + align:start position:0% +sweep inhibition from high to low such +that cells that again the strongest + + align:start position:0% +that cells that again the strongest + + + align:start position:0% +that cells that again the strongest +input fire earlier and this will + + align:start position:0% +input fire earlier and this will + + + align:start position:0% +input fire earlier and this will +reactivate a sequence so the difference + + align:start position:0% +reactivate a sequence so the difference + + + align:start position:0% +reactivate a sequence so the difference +between a theta sequence and a + + align:start position:0% +between a theta sequence and a + + + align:start position:0% +between a theta sequence and a +reactivated sequence is really just + + align:start position:0% +reactivated sequence is really just + + + align:start position:0% +reactivated sequence is really just +where's the input coming from if the + + align:start position:0% +where's the input coming from if the + + + align:start position:0% +where's the input coming from if the +inputs coming from what I'm actually + + align:start position:0% +inputs coming from what I'm actually + + + align:start position:0% +inputs coming from what I'm actually +experiencing right now now it's a theta + + align:start position:0% +experiencing right now now it's a theta + + + align:start position:0% +experiencing right now now it's a theta +sequence + + align:start position:0% +sequence + + + align:start position:0% +sequence +and as I move the input changes + + align:start position:0% +and as I move the input changes + + + align:start position:0% +and as I move the input changes +systematically and so again it looks + + align:start position:0% +systematically and so again it looks + + + align:start position:0% +systematically and so again it looks +like it's encoding information about + + align:start position:0% +like it's encoding information about + + + align:start position:0% +like it's encoding information about +space if I'm now offline and this + + align:start position:0% +space if I'm now offline and this + + + align:start position:0% +space if I'm now offline and this +information is being delivered to the + + align:start position:0% +information is being delivered to the + + + align:start position:0% +information is being delivered to the +hippocampus from some other source you + + align:start position:0% +hippocampus from some other source you + + + align:start position:0% +hippocampus from some other source you +can apply exactly the same operation get + + align:start position:0% +can apply exactly the same operation get + + + align:start position:0% +can apply exactly the same operation get +the same kind of sequence it's just now + + align:start position:0% +the same kind of sequence it's just now + + + align:start position:0% +the same kind of sequence it's just now +it's on information that is not tied to + + align:start position:0% +it's on information that is not tied to + + + align:start position:0% +it's on information that is not tied to +be sort of your you know immediate + + align:start position:0% +be sort of your you know immediate + + + align:start position:0% +be sort of your you know immediate +context or location so that's the only + + align:start position:0% +context or location so that's the only + + + align:start position:0% +context or location so that's the only +difference + + align:start position:0% +difference + + + align:start position:0% +difference +where is the input coming from now + + align:start position:0% +where is the input coming from now + + + align:start position:0% +where is the input coming from now +further if you think about this model + + align:start position:0% +further if you think about this model + + + align:start position:0% +further if you think about this model +you can imagine well thats of the depth + + align:start position:0% +you can imagine well thats of the depth + + + align:start position:0% +you can imagine well thats of the depth +of disinhibition could actually affect + + align:start position:0% +of disinhibition could actually affect + + + align:start position:0% +of disinhibition could actually affect +the length of the sequence but that's + + align:start position:0% +the length of the sequence but that's + + + align:start position:0% +the length of the sequence but that's +just sort of a mechanistic thing and if + + align:start position:0% +just sort of a mechanistic thing and if + + + align:start position:0% +just sort of a mechanistic thing and if +you actually look at the mechanisms that + + align:start position:0% +you actually look at the mechanisms that + + + align:start position:0% +you actually look at the mechanisms that +regulate sharp wave ripples in the theta + + align:start position:0% +regulate sharp wave ripples in the theta + + + align:start position:0% +regulate sharp wave ripples in the theta +oscillation it s it basically comes from + + align:start position:0% +oscillation it s it basically comes from + + + align:start position:0% +oscillation it s it basically comes from +the same structure it's a structure that + + align:start position:0% +the same structure it's a structure that + + + align:start position:0% +the same structure it's a structure that +regulates acetylcholine and that's a + + align:start position:0% +regulates acetylcholine and that's a + + + align:start position:0% +regulates acetylcholine and that's a +it's a neuromodulator that's associated + + align:start position:0% +it's a neuromodulator that's associated + + + align:start position:0% +it's a neuromodulator that's associated +with attention in memory and the + + align:start position:0% +with attention in memory and the + + + align:start position:0% +with attention in memory and the +structure called the medial septum so + + align:start position:0% +structure called the medial septum so + + + align:start position:0% +structure called the medial septum so +the medial septum provides the drive the + + align:start position:0% +the medial septum provides the drive the + + + align:start position:0% +the medial septum provides the drive the +cholinergic drive of the hippocampus + + align:start position:0% +cholinergic drive of the hippocampus + + + align:start position:0% +cholinergic drive of the hippocampus +damage the medial septum loss of + + align:start position:0% +damage the medial septum loss of + + + align:start position:0% +damage the medial septum loss of +cholinergic tone was one of the dominant + + align:start position:0% +cholinergic tone was one of the dominant + + + align:start position:0% +cholinergic tone was one of the dominant +models of nerd nerd degenerative + + align:start position:0% +models of nerd nerd degenerative + + + align:start position:0% +models of nerd nerd degenerative +cognitive and memory loss in Alzheimer's + + align:start position:0% +cognitive and memory loss in Alzheimer's + + + align:start position:0% +cognitive and memory loss in Alzheimer's +disease so what you find is one of the + + align:start position:0% +disease so what you find is one of the + + + align:start position:0% +disease so what you find is one of the +earliest indications of + + align:start position:0% +earliest indications of + + + align:start position:0% +earliest indications of +neurodegenerative damage in Alzheimer's + + align:start position:0% +neurodegenerative damage in Alzheimer's + + + align:start position:0% +neurodegenerative damage in Alzheimer's +is the loss of cholinergic tone and the + + align:start position:0% +is the loss of cholinergic tone and the + + + align:start position:0% +is the loss of cholinergic tone and the +systems that begin to break down are the + + align:start position:0% +systems that begin to break down are the + + + align:start position:0% +systems that begin to break down are the +systems that actually fall along this + + align:start position:0% +systems that actually fall along this + + + align:start position:0% +systems that actually fall along this +limbic pathway starting with hippocampus + + align:start position:0% +limbic pathway starting with hippocampus + + + align:start position:0% +limbic pathway starting with hippocampus +central cortex so as though the + + align:start position:0% +central cortex so as though the + + + align:start position:0% +central cortex so as though the +cholinergic system that regulates the + + align:start position:0% +cholinergic system that regulates the + + + align:start position:0% +cholinergic system that regulates the +expression of this oscillation in the + + align:start position:0% +expression of this oscillation in the + + + align:start position:0% +expression of this oscillation in the +hippocampus when it breaks down it leads + + align:start position:0% +hippocampus when it breaks down it leads + + + align:start position:0% +hippocampus when it breaks down it leads +to general memory loss in you know + + align:start position:0% +to general memory loss in you know + + + align:start position:0% +to general memory loss in you know +disruption and turns out the medial + + align:start position:0% +disruption and turns out the medial + + + align:start position:0% +disruption and turns out the medial +septum is also involved in regulating + + align:start position:0% +septum is also involved in regulating + + + align:start position:0% +septum is also involved in regulating +the expression of these sharp wave + + align:start position:0% +the expression of these sharp wave + + + align:start position:0% +the expression of these sharp wave +ripples so same system different modes + + align:start position:0% +ripples so same system different modes + + + align:start position:0% +ripples so same system different modes +one you know quiet one sort of active + + align:start position:0% +one you know quiet one sort of active + + + align:start position:0% +one you know quiet one sort of active +online when inactive + + align:start position:0% +online when inactive + + + align:start position:0% +online when inactive +offline same kind of modulation of + + align:start position:0% +offline same kind of modulation of + + + align:start position:0% +offline same kind of modulation of +excitability through an addition but + + align:start position:0% +excitability through an addition but + + + align:start position:0% +excitability through an addition but +that's the idea simple model sweep + + align:start position:0% +that's the idea simple model sweep + + + align:start position:0% +that's the idea simple model sweep +inhibition that gives you the sequences + + align:start position:0% +inhibition that gives you the sequences + + + align:start position:0% +inhibition that gives you the sequences +and then control the input you control + + align:start position:0% +and then control the input you control + + + align:start position:0% +and then control the input you control +the input to control the content you + + align:start position:0% +the input to control the content you + + + align:start position:0% +the input to control the content you +control the inhibition to control the + + align:start position:0% +control the inhibition to control the + + + align:start position:0% +control the inhibition to control the +structure of the timing those are the + + align:start position:0% +structure of the timing those are the + + + align:start position:0% +structure of the timing those are the +two things so the question is how could + + align:start position:0% +two things so the question is how could + + + align:start position:0% +two things so the question is how could +you control the input when we kind of + + align:start position:0% +you control the input when we kind of + + + align:start position:0% +you control the input when we kind of +thinking about what is the input into + + align:start position:0% +thinking about what is the input into + + + align:start position:0% +thinking about what is the input into +the hippocampus under these two + + align:start position:0% +the hippocampus under these two + + + align:start position:0% +the hippocampus under these two +conditions and as I mentioned + + align:start position:0% +conditions and as I mentioned + + + align:start position:0% +conditions and as I mentioned +hippocampus + + align:start position:0% +hippocampus + + + align:start position:0% +hippocampus +you've got the internal cortex Central + + align:start position:0% +you've got the internal cortex Central + + + align:start position:0% +you've got the internal cortex Central +cortex gets information across the brain + + align:start position:0% +cortex gets information across the brain + + + align:start position:0% +cortex gets information across the brain +is sort of the sensory Association our + + align:start position:0% +is sort of the sensory Association our + + + align:start position:0% +is sort of the sensory Association our +visual cortex auditory for this there + + align:start position:0% +visual cortex auditory for this there + + + align:start position:0% +visual cortex auditory for this there +all this information about the world + + align:start position:0% +all this information about the world + + + align:start position:0% +all this information about the world +converging on the hippocampus and then + + align:start position:0% +converging on the hippocampus and then + + + align:start position:0% +converging on the hippocampus and then +getting modulated and so you can think + + align:start position:0% +getting modulated and so you can think + + + align:start position:0% +getting modulated and so you can think +about let's look in for instance visual + + align:start position:0% +about let's look in for instance visual + + + align:start position:0% +about let's look in for instance visual +cortex so if we simultaneous recording + + align:start position:0% +cortex so if we simultaneous recording + + + align:start position:0% +cortex so if we simultaneous recording +video cortex and hippocampus we could + + align:start position:0% +video cortex and hippocampus we could + + + align:start position:0% +video cortex and hippocampus we could +see how these two structures communicate + + align:start position:0% +see how these two structures communicate + + + align:start position:0% +see how these two structures communicate +and when we do this in a simple task is + + align:start position:0% +and when we do this in a simple task is + + + align:start position:0% +and when we do this in a simple task is +like little figure eight tasks and I + + align:start position:0% +like little figure eight tasks and I + + + align:start position:0% +like little figure eight tasks and I +won't go into a lot of the details but + + align:start position:0% +won't go into a lot of the details but + + + align:start position:0% +won't go into a lot of the details but +one interesting thing that came out from + + align:start position:0% +one interesting thing that came out from + + + align:start position:0% +one interesting thing that came out from +doing this experiment recording visual + + align:start position:0% +doing this experiment recording visual + + + align:start position:0% +doing this experiment recording visual +cortex and hippocampus is that recording + + align:start position:0% +cortex and hippocampus is that recording + + + align:start position:0% +cortex and hippocampus is that recording +in the visual cortex when an animal is + + align:start position:0% +in the visual cortex when an animal is + + + align:start position:0% +in the visual cortex when an animal is +moving in space what you find is cells + + align:start position:0% +moving in space what you find is cells + + + align:start position:0% +moving in space what you find is cells +and the visual cortex have spatial like + + align:start position:0% +and the visual cortex have spatial like + + + align:start position:0% +and the visual cortex have spatial like +receptive fields similar to the + + align:start position:0% +receptive fields similar to the + + + align:start position:0% +receptive fields similar to the +hippocampus they're not a spatially + + align:start position:0% +hippocampus they're not a spatially + + + align:start position:0% +hippocampus they're not a spatially +tuned but here for instance r88 visual + + align:start position:0% +tuned but here for instance r88 visual + + + align:start position:0% +tuned but here for instance r88 visual +cortical cells and you can see that they + + align:start position:0% +cortical cells and you can see that they + + + align:start position:0% +cortical cells and you can see that they +fire they fire in a sequence they'll + + align:start position:0% +fire they fire in a sequence they'll + + + align:start position:0% +fire they fire in a sequence they'll +have different spatial receptive fields + + align:start position:0% +have different spatial receptive fields + + + align:start position:0% +have different spatial receptive fields +this shows where the where this one + + align:start position:0% +this shows where the where this one + + + align:start position:0% +this shows where the where this one +visual cortical cell likes to fire + + align:start position:0% +visual cortical cell likes to fire + + + align:start position:0% +visual cortical cell likes to fire +different visual cortical cells will + + align:start position:0% +different visual cortical cells will + + + align:start position:0% +different visual cortical cells will +fire at different locations so you when + + align:start position:0% +fire at different locations so you when + + + align:start position:0% +fire at different locations so you when +animals are moving in space you actually + + align:start position:0% +animals are moving in space you actually + + + align:start position:0% +animals are moving in space you actually +see sequential activation of these + + align:start position:0% +see sequential activation of these + + + align:start position:0% +see sequential activation of these +visual cortical responses and so if you + + align:start position:0% +visual cortical responses and so if you + + + align:start position:0% +visual cortical responses and so if you +have visual sequences visual perceptual + + align:start position:0% +have visual sequences visual perceptual + + + align:start position:0% +have visual sequences visual perceptual +sequences in hippocampal spatial + + align:start position:0% +sequences in hippocampal spatial + + + align:start position:0% +sequences in hippocampal spatial +sequences one question is how do those + + align:start position:0% +sequences one question is how do those + + + align:start position:0% +sequences one question is how do those +sequences how do those sequences relate + + align:start position:0% +sequences how do those sequences relate + + + align:start position:0% +sequences how do those sequences relate +offline when they annal for instance + + align:start position:0% +offline when they annal for instance + + + align:start position:0% +offline when they annal for instance +during sleep so you have sequences + + align:start position:0% +during sleep so you have sequences + + + align:start position:0% +during sleep so you have sequences +during sleep and the hippocampus + + align:start position:0% +during sleep and the hippocampus + + + align:start position:0% +during sleep and the hippocampus +sequence is varying sleep in the visual + + align:start position:0% +sequence is varying sleep in the visual + + + align:start position:0% +sequence is varying sleep in the visual +cortex and it turns out that those two + + align:start position:0% +cortex and it turns out that those two + + + align:start position:0% +cortex and it turns out that those two +things are actually they're correlated + + align:start position:0% +things are actually they're correlated + + + align:start position:0% +things are actually they're correlated +so in hippocampus + + align:start position:0% +so in hippocampus + + + align:start position:0% +so in hippocampus +plays out a spatial sequence the visual + + align:start position:0% +plays out a spatial sequence the visual + + + align:start position:0% +plays out a spatial sequence the visual +cortex plays out a visual sequence that + + align:start position:0% +cortex plays out a visual sequence that + + + align:start position:0% +cortex plays out a visual sequence that +corresponds to the visual responses at + + align:start position:0% +corresponds to the visual responses at + + + align:start position:0% +corresponds to the visual responses at +those locations so hippocampus plays out + + align:start position:0% +those locations so hippocampus plays out + + + align:start position:0% +those locations so hippocampus plays out +sequence of where it was visual cortex + + align:start position:0% +sequence of where it was visual cortex + + + align:start position:0% +sequence of where it was visual cortex +expresses the visual visual stimuli that + + align:start position:0% +expresses the visual visual stimuli that + + + align:start position:0% +expresses the visual visual stimuli that +were present along that sequence one + + align:start position:0% +were present along that sequence one + + + align:start position:0% +were present along that sequence one +thing about these sequences when we're + + align:start position:0% +thing about these sequences when we're + + + align:start position:0% +thing about these sequences when we're +looking when we were looking at + + align:start position:0% +looking when we were looking at + + + align:start position:0% +looking when we were looking at +hippocampal neocortical interactions is + + align:start position:0% +hippocampal neocortical interactions is + + + align:start position:0% +hippocampal neocortical interactions is +that the sequences are now at a much + + align:start position:0% +that the sequences are now at a much + + + align:start position:0% +that the sequences are now at a much +longer time scale and in fact this time + + align:start position:0% +longer time scale and in fact this time + + + align:start position:0% +longer time scale and in fact this time +scale which here is about on the order + + align:start position:0% +scale which here is about on the order + + + align:start position:0% +scale which here is about on the order +of about half a second to a second + + align:start position:0% +of about half a second to a second + + + align:start position:0% +of about half a second to a second +corresponds to another oscillation that + + align:start position:0% +corresponds to another oscillation that + + + align:start position:0% +corresponds to another oscillation that +is characteristic of sleep known as the + + align:start position:0% +is characteristic of sleep known as the + + + align:start position:0% +is characteristic of sleep known as the +slow oscillation so when you go to sleep + + align:start position:0% +slow oscillation so when you go to sleep + + + align:start position:0% +slow oscillation so when you go to sleep +brain rhythm the oscillations the + + align:start position:0% +brain rhythm the oscillations the + + + align:start position:0% +brain rhythm the oscillations the +dominant frequency start to slow down + + align:start position:0% +dominant frequency start to slow down + + + align:start position:0% +dominant frequency start to slow down +and you'll get this oscillation in this + + align:start position:0% +and you'll get this oscillation in this + + + align:start position:0% +and you'll get this oscillation in this +one Hertz or so frequency range that + + align:start position:0% +one Hertz or so frequency range that + + + align:start position:0% +one Hertz or so frequency range that +looks like if you record activity from a + + align:start position:0% +looks like if you record activity from a + + + align:start position:0% +looks like if you record activity from a +bunch of cells it looks like this this + + align:start position:0% +bunch of cells it looks like this this + + + align:start position:0% +bunch of cells it looks like this this +is the activity of a whole bunch of + + align:start position:0% +is the activity of a whole bunch of + + + align:start position:0% +is the activity of a whole bunch of +cells in the visual cortex in the + + align:start position:0% +cells in the visual cortex in the + + + align:start position:0% +cells in the visual cortex in the +hippocampus and you see that the + + align:start position:0% +hippocampus and you see that the + + + align:start position:0% +hippocampus and you see that the +activity is flipping between lots of + + align:start position:0% +activity is flipping between lots of + + + align:start position:0% +activity is flipping between lots of +cells active no cells active these are + + align:start position:0% +cells active no cells active these are + + + align:start position:0% +cells active no cells active these are +the so-called up-and-down states of + + align:start position:0% +the so-called up-and-down states of + + + align:start position:0% +the so-called up-and-down states of +cells during sleep that every half a + + align:start position:0% +cells during sleep that every half a + + + align:start position:0% +cells during sleep that every half a +second to a second or so many cells will + + align:start position:0% +second to a second or so many cells will + + + align:start position:0% +second to a second or so many cells will +become active then they'll all be shut + + align:start position:0% +become active then they'll all be shut + + + align:start position:0% +become active then they'll all be shut +off they'll become active again so + + align:start position:0% +off they'll become active again so + + + align:start position:0% +off they'll become active again so +you're flipping between is up and down + + align:start position:0% +you're flipping between is up and down + + + align:start position:0% +you're flipping between is up and down +like States and if you look at these up + + align:start position:0% +like States and if you look at these up + + + align:start position:0% +like States and if you look at these up +and down states in the visual cortex and + + align:start position:0% +and down states in the visual cortex and + + + align:start position:0% +and down states in the visual cortex and +you look at similar activity in the + + align:start position:0% +you look at similar activity in the + + + align:start position:0% +you look at similar activity in the +hippocampus you see these up and down + + align:start position:0% +hippocampus you see these up and down + + + align:start position:0% +hippocampus you see these up and down +like states in the hippocampus as well + + align:start position:0% +like states in the hippocampus as well + + + align:start position:0% +like states in the hippocampus as well +but you'll notice that the up state in + + align:start position:0% +but you'll notice that the up state in + + + align:start position:0% +but you'll notice that the up state in +the neocortex leads up state in the + + align:start position:0% +the neocortex leads up state in the + + + align:start position:0% +the neocortex leads up state in the +hippocampus so a neocortex first then + + align:start position:0% +hippocampus so a neocortex first then + + + align:start position:0% +hippocampus so a neocortex first then +hippocampus in your cortex tippecanoe + + align:start position:0% +hippocampus in your cortex tippecanoe + + + align:start position:0% +hippocampus in your cortex tippecanoe +clue neocortex seems to lead so again + + align:start position:0% +clue neocortex seems to lead so again + + + align:start position:0% +clue neocortex seems to lead so again +this question of who is providing the + + align:start position:0% +this question of who is providing the + + + align:start position:0% +this question of who is providing the +input you know that simple model or I'm + + align:start position:0% +input you know that simple model or I'm + + + align:start position:0% +input you know that simple model or I'm +sweeping inhibition during during the + + align:start position:0% +sweeping inhibition during during the + + + align:start position:0% +sweeping inhibition during during the +theta during active behavior that + + align:start position:0% +theta during active behavior that + + + align:start position:0% +theta during active behavior that +information is coming in from + + align:start position:0% +information is coming in from + + + align:start position:0% +information is coming in from +perceptions what I'm actually during + + align:start position:0% +perceptions what I'm actually during + + + align:start position:0% +perceptions what I'm actually during +sleep crisis where is that information + + align:start position:0% +sleep crisis where is that information + + + align:start position:0% +sleep crisis where is that information +coming from well this would say this is + + align:start position:0% +coming from well this would say this is + + + align:start position:0% +coming from well this would say this is +where it's coming from it's coming from + + align:start position:0% +where it's coming from it's coming from + + + align:start position:0% +where it's coming from it's coming from +these cortical areas let's say sensory + + align:start position:0% +these cortical areas let's say sensory + + + align:start position:0% +these cortical areas let's say sensory +visual cortical areas turn on they + + align:start position:0% +visual cortical areas turn on they + + + align:start position:0% +visual cortical areas turn on they +provide the information that the campus + + align:start position:0% +provide the information that the campus + + + align:start position:0% +provide the information that the campus +now the hippocampus turns on + + align:start position:0% +now the hippocampus turns on + + + align:start position:0% +now the hippocampus turns on +the campus responding to input coming in + + align:start position:0% +the campus responding to input coming in + + + align:start position:0% +the campus responding to input coming in +from sensory cortex if that's the case + + align:start position:0% +from sensory cortex if that's the case + + + align:start position:0% +from sensory cortex if that's the case +could we manipulate hippocampal activity + + align:start position:0% +could we manipulate hippocampal activity + + + align:start position:0% +could we manipulate hippocampal activity +by manipulating sensory cortex so this + + align:start position:0% +by manipulating sensory cortex so this + + + align:start position:0% +by manipulating sensory cortex so this +experiment simple experiment answer was + + align:start position:0% +experiment simple experiment answer was + + + align:start position:0% +experiment simple experiment answer was +yes need in this case we used the + + align:start position:0% +yes need in this case we used the + + + align:start position:0% +yes need in this case we used the +auditory system one of the reason for + + align:start position:0% +auditory system one of the reason for + + + align:start position:0% +auditory system one of the reason for +use the auditory system is unlike the + + align:start position:0% +use the auditory system is unlike the + + + align:start position:0% +use the auditory system is unlike the +visual system auditory system remains in + + align:start position:0% +visual system auditory system remains in + + + align:start position:0% +visual system auditory system remains in +a state of persistent and vigilance even + + align:start position:0% +a state of persistent and vigilance even + + + align:start position:0% +a state of persistent and vigilance even +during sleep auditory cortical responses + + align:start position:0% +during sleep auditory cortical responses + + + align:start position:0% +during sleep auditory cortical responses +even animal goes to sleep measure to + + align:start position:0% +even animal goes to sleep measure to + + + align:start position:0% +even animal goes to sleep measure to +measure auditory cortical response the + + align:start position:0% +measure auditory cortical response the + + + align:start position:0% +measure auditory cortical response the +same as when it's awake so essentially + + align:start position:0% +same as when it's awake so essentially + + + align:start position:0% +same as when it's awake so essentially +the auditory cortex stays vigilant + + align:start position:0% +the auditory cortex stays vigilant + + + align:start position:0% +the auditory cortex stays vigilant +during sleep which has clear + + align:start position:0% +during sleep which has clear + + + align:start position:0% +during sleep which has clear +evolutionary value so sleep you know + + align:start position:0% +evolutionary value so sleep you know + + + align:start position:0% +evolutionary value so sleep you know +it's trying to minimise arousal by you + + align:start position:0% +it's trying to minimise arousal by you + + + align:start position:0% +it's trying to minimise arousal by you +know sort of shutting off a visual input + + align:start position:0% +know sort of shutting off a visual input + + + align:start position:0% +know sort of shutting off a visual input +which may be of limited value anyway + + align:start position:0% +which may be of limited value anyway + + + align:start position:0% +which may be of limited value anyway +given you know of sort of the circadian + + align:start position:0% +given you know of sort of the circadian + + + align:start position:0% +given you know of sort of the circadian +nocturnal nature of you know of sort of + + align:start position:0% +nocturnal nature of you know of sort of + + + align:start position:0% +nocturnal nature of you know of sort of +visual stimuli so you can't see anything + + align:start position:0% +visual stimuli so you can't see anything + + + align:start position:0% +visual stimuli so you can't see anything +might as well actually close your eyes + + align:start position:0% +might as well actually close your eyes + + + align:start position:0% +might as well actually close your eyes +but you can still hear things + + align:start position:0% +but you can still hear things + + + align:start position:0% +but you can still hear things +so you and other animals are still + + align:start position:0% +so you and other animals are still + + + align:start position:0% +so you and other animals are still +listening if you hear you know pickup + + align:start position:0% +listening if you hear you know pickup + + + align:start position:0% +listening if you hear you know pickup +threats that might require that they + + align:start position:0% +threats that might require that they + + + align:start position:0% +threats that might require that they +actually work up so anyway taking + + align:start position:0% +actually work up so anyway taking + + + align:start position:0% +actually work up so anyway taking +advantage of that auditory system on so + + align:start position:0% +advantage of that auditory system on so + + + align:start position:0% +advantage of that auditory system on so +training animal on task where it learns + + align:start position:0% +training animal on task where it learns + + + align:start position:0% +training animal on task where it learns +to associate auditory cues with + + align:start position:0% +to associate auditory cues with + + + align:start position:0% +to associate auditory cues with +locations one sound right sound means go + + align:start position:0% +locations one sound right sound means go + + + align:start position:0% +locations one sound right sound means go +over here to get food left sound means + + align:start position:0% +over here to get food left sound means + + + align:start position:0% +over here to get food left sound means +go over there to get food very simple + + align:start position:0% +go over there to get food very simple + + + align:start position:0% +go over there to get food very simple +task then animal goes to sleep and you + + align:start position:0% +task then animal goes to sleep and you + + + align:start position:0% +task then animal goes to sleep and you +just continue to play the sounds so it's + + align:start position:0% +just continue to play the sounds so it's + + + align:start position:0% +just continue to play the sounds so it's +learned something and now you try to + + align:start position:0% +learned something and now you try to + + + align:start position:0% +learned something and now you try to +bias cortical activity during sleep and + + align:start position:0% +bias cortical activity during sleep and + + + align:start position:0% +bias cortical activity during sleep and +ask what does that do so this is the + + align:start position:0% +ask what does that do so this is the + + + align:start position:0% +ask what does that do so this is the +idea when the animal is actually running + + align:start position:0% +idea when the animal is actually running + + + align:start position:0% +idea when the animal is actually running +we can decode hippocampal activity so we + + align:start position:0% +we can decode hippocampal activity so we + + + align:start position:0% +we can decode hippocampal activity so we +can tell oh here's a hippocampal pattern + + align:start position:0% +can tell oh here's a hippocampal pattern + + + align:start position:0% +can tell oh here's a hippocampal pattern +that corresponds to the left side or the + + align:start position:0% +that corresponds to the left side or the + + + align:start position:0% +that corresponds to the left side or the +right side and in this case when the + + align:start position:0% +right side and in this case when the + + + align:start position:0% +right side and in this case when the +animal is performing the task play the + + align:start position:0% +animal is performing the task play the + + + align:start position:0% +animal is performing the task play the +right hand sound animal goes to the + + align:start position:0% +right hand sound animal goes to the + + + align:start position:0% +right hand sound animal goes to the +right hand side see this in the + + align:start position:0% +right hand side see this in the + + + align:start position:0% +right hand side see this in the +hippocampal response play left hand + + align:start position:0% +hippocampal response play left hand + + + align:start position:0% +hippocampal response play left hand +sound and I'll go to the left hand side + + align:start position:0% +sound and I'll go to the left hand side + + + align:start position:0% +sound and I'll go to the left hand side +again left hand plays fields and they + + align:start position:0% +again left hand plays fields and they + + + align:start position:0% +again left hand plays fields and they +don't was on the left right hand plays + + align:start position:0% +don't was on the left right hand plays + + + align:start position:0% +don't was on the left right hand plays +fields on it so this is this is what the + + align:start position:0% +fields on it so this is this is what the + + + align:start position:0% +fields on it so this is this is what the +experiment and the behavior looks like + + align:start position:0% +experiment and the behavior looks like + + + align:start position:0% +experiment and the behavior looks like +from the standpoint of the hippocampus + + align:start position:0% +from the standpoint of the hippocampus + + + align:start position:0% +from the standpoint of the hippocampus +very clear right right right sound right + + align:start position:0% +very clear right right right sound right + + + align:start position:0% +very clear right right right sound right +hippocampus right play cells left sound + + align:start position:0% +hippocampus right play cells left sound + + + align:start position:0% +hippocampus right play cells left sound +left play cells but now the animals + + align:start position:0% +left play cells but now the animals + + + align:start position:0% +left play cells but now the animals +going to go to sleep + + align:start position:0% +going to go to sleep + + + align:start position:0% +going to go to sleep +and we're gonna do the same thing + + align:start position:0% +and we're gonna do the same thing + + + align:start position:0% +and we're gonna do the same thing +continue to play the right sounds and + + align:start position:0% +continue to play the right sounds and + + + align:start position:0% +continue to play the right sounds and +the left sounds it's just that now the + + align:start position:0% +the left sounds it's just that now the + + + align:start position:0% +the left sounds it's just that now the +animal is not actually moving on the + + align:start position:0% +animal is not actually moving on the + + + align:start position:0% +animal is not actually moving on the +track and so we ask does that + + align:start position:0% +track and so we ask does that + + + align:start position:0% +track and so we ask does that +can we buy us the reactivated sequences + + align:start position:0% +can we buy us the reactivated sequences + + + align:start position:0% +can we buy us the reactivated sequences +that you get so there's the same thing + + align:start position:0% +that you get so there's the same thing + + + align:start position:0% +that you get so there's the same thing +now animals awake but now it's going to + + align:start position:0% +now animals awake but now it's going to + + + align:start position:0% +now animals awake but now it's going to +go to sleep and we just keep playing the + + align:start position:0% +go to sleep and we just keep playing the + + + align:start position:0% +go to sleep and we just keep playing the +sounds a little ticks there indicate the + + align:start position:0% +sounds a little ticks there indicate the + + + align:start position:0% +sounds a little ticks there indicate the +delivery of sounds every 10 seconds or + + align:start position:0% +delivery of sounds every 10 seconds or + + + align:start position:0% +delivery of sounds every 10 seconds or +so so we play a sound and now we look at + + align:start position:0% +so so we play a sound and now we look at + + + align:start position:0% +so so we play a sound and now we look at +the response the difference here is that + + align:start position:0% +the response the difference here is that + + + align:start position:0% +the response the difference here is that +animals not it's not running it's not + + align:start position:0% +animals not it's not running it's not + + + align:start position:0% +animals not it's not running it's not +behaving sound response now will decode + + align:start position:0% +behaving sound response now will decode + + + align:start position:0% +behaving sound response now will decode +the activity so here for instance we + + align:start position:0% +the activity so here for instance we + + + align:start position:0% +the activity so here for instance we +take a little short window here about + + align:start position:0% +take a little short window here about + + + align:start position:0% +take a little short window here about +half a second and what you see is this + + align:start position:0% +half a second and what you see is this + + + align:start position:0% +half a second and what you see is this +is this up like state multi-unit + + align:start position:0% +is this up like state multi-unit + + + align:start position:0% +is this up like state multi-unit +activity lots of cells firing decode + + align:start position:0% +activity lots of cells firing decode + + + align:start position:0% +activity lots of cells firing decode +activity and ask when you play the left + + align:start position:0% +activity and ask when you play the left + + + align:start position:0% +activity and ask when you play the left +sound + + align:start position:0% +sound + + + align:start position:0% +sound +what does activity decode to and here + + align:start position:0% +what does activity decode to and here + + + align:start position:0% +what does activity decode to and here +you see okay it's gonna decode into the + + align:start position:0% +you see okay it's gonna decode into the + + + align:start position:0% +you see okay it's gonna decode into the +left hand side so that's the basic basic + + align:start position:0% +left hand side so that's the basic basic + + + align:start position:0% +left hand side so that's the basic basic +hypothesis play left sound you get the + + align:start position:0% +hypothesis play left sound you get the + + + align:start position:0% +hypothesis play left sound you get the +replay of the left side of the of the + + align:start position:0% +replay of the left side of the of the + + + align:start position:0% +replay of the left side of the of the +track you play the right side you get + + align:start position:0% +track you play the right side you get + + + align:start position:0% +track you play the right side you get +reactivation of the right side of the + + align:start position:0% +reactivation of the right side of the + + + align:start position:0% +reactivation of the right side of the +track and that's that's what you get so + + align:start position:0% +track and that's that's what you get so + + + align:start position:0% +track and that's that's what you get so +when you play the left hand sound left + + align:start position:0% +when you play the left hand sound left + + + align:start position:0% +when you play the left hand sound left +sound bias activates cell play cells on + + align:start position:0% +sound bias activates cell play cells on + + + align:start position:0% +sound bias activates cell play cells on +the left side right side bias biases + + align:start position:0% +the left side right side bias biases + + + align:start position:0% +the left side right side bias biases +place also on the right and you can do + + align:start position:0% +place also on the right and you can do + + + align:start position:0% +place also on the right and you can do +the same kind of psychophysical + + align:start position:0% +the same kind of psychophysical + + + align:start position:0% +the same kind of psychophysical +experiments which has been done in + + align:start position:0% +experiments which has been done in + + + align:start position:0% +experiments which has been done in +humans either with with different mode + + align:start position:0% +humans either with with different mode + + + align:start position:0% +humans either with with different mode +different sensory modalities it's been + + align:start position:0% +different sensory modalities it's been + + + align:start position:0% +different sensory modalities it's been +done on olfaction it's also been done in + + align:start position:0% +done on olfaction it's also been done in + + + align:start position:0% +done on olfaction it's also been done in +audition so the equivalent experiment + + align:start position:0% +audition so the equivalent experiment + + + align:start position:0% +audition so the equivalent experiment +using auditory cueing in humans where + + align:start position:0% +using auditory cueing in humans where + + + align:start position:0% +using auditory cueing in humans where +you have people learn the simple task + + align:start position:0% +you have people learn the simple task + + + align:start position:0% +you have people learn the simple task +this was done in Ken Taylor's lab or + + align:start position:0% +this was done in Ken Taylor's lab or + + + align:start position:0% +this was done in Ken Taylor's lab or +they do the simple spatial matching game + + align:start position:0% +they do the simple spatial matching game + + + align:start position:0% +they do the simple spatial matching game +it's like you know where's the cat card + + align:start position:0% +it's like you know where's the cat card + + + align:start position:0% +it's like you know where's the cat card +where's the teapot card the variant here + + align:start position:0% +where's the teapot card the variant here + + + align:start position:0% +where's the teapot card the variant here +was when they flipped over the cat card + + align:start position:0% +was when they flipped over the cat card + + + align:start position:0% +was when they flipped over the cat card +they would play the cat sound meow they + + align:start position:0% +they would play the cat sound meow they + + + align:start position:0% +they would play the cat sound meow they +flip over the teapot sound they play a + + align:start position:0% +flip over the teapot sound they play a + + + align:start position:0% +flip over the teapot sound they play a +little you know associated an auditory + + align:start position:0% +little you know associated an auditory + + + align:start position:0% +little you know associated an auditory +cue teapot whistle and then people go to + + align:start position:0% +cue teapot whistle and then people go to + + + align:start position:0% +cue teapot whistle and then people go to +sleep and during sleep they would play + + align:start position:0% +sleep and during sleep they would play + + + align:start position:0% +sleep and during sleep they would play +either like the cat sound or the teapot + + align:start position:0% +either like the cat sound or the teapot + + + align:start position:0% +either like the cat sound or the teapot +sound and they found out when they would + + align:start position:0% +sound and they found out when they would + + + align:start position:0% +sound and they found out when they would +wake up and now they do the task they're + + align:start position:0% +wake up and now they do the task they're + + + align:start position:0% +wake up and now they do the task they're +better at if they played the cat sound + + align:start position:0% +better at if they played the cat sound + + + align:start position:0% +better at if they played the cat sound +during sleep they were better at + + align:start position:0% +during sleep they were better at + + + align:start position:0% +during sleep they were better at +remembering locations of cats then than + + align:start position:0% +remembering locations of cats then than + + + align:start position:0% +remembering locations of cats then than +the whistle so this says not only to + + align:start position:0% +the whistle so this says not only to + + + align:start position:0% +the whistle so this says not only to +sleep actually contribute to memory but + + align:start position:0% +sleep actually contribute to memory but + + + align:start position:0% +sleep actually contribute to memory but +it's selective and it not only is + + align:start position:0% +it's selective and it not only is + + + align:start position:0% +it's selective and it not only is +selective but it can be influenced it + + align:start position:0% +selective but it can be influenced it + + + align:start position:0% +selective but it can be influenced it +can be biased you can direct the nature + + align:start position:0% +can be biased you can direct the nature + + + align:start position:0% +can be biased you can direct the nature +of memory processing and then our + + align:start position:0% +of memory processing and then our + + + align:start position:0% +of memory processing and then our +experiments suggest that well one of the + + align:start position:0% +experiments suggest that well one of the + + + align:start position:0% +experiments suggest that well one of the +one of the consequences of this kind of + + align:start position:0% +one of the consequences of this kind of + + + align:start position:0% +one of the consequences of this kind of +sleep manipulation would be bias the + + align:start position:0% +sleep manipulation would be bias the + + + align:start position:0% +sleep manipulation would be bias the +memory reactivation in the hippocampus + + align:start position:0% +memory reactivation in the hippocampus + + + align:start position:0% +memory reactivation in the hippocampus +and so the idea is simple and that is + + align:start position:0% +and so the idea is simple and that is + + + align:start position:0% +and so the idea is simple and that is +that cortex bias is the state that the + + align:start position:0% +that cortex bias is the state that the + + + align:start position:0% +that cortex bias is the state that the +hippocampus gets and then the + + align:start position:0% +hippocampus gets and then the + + + align:start position:0% +hippocampus gets and then the +hippocampus takes that state sweeps + + align:start position:0% +hippocampus takes that state sweeps + + + align:start position:0% +hippocampus takes that state sweeps +inhibition replays a sequence and that + + align:start position:0% +inhibition replays a sequence and that + + + align:start position:0% +inhibition replays a sequence and that +sequence thing gets played back to the + + align:start position:0% +sequence thing gets played back to the + + + align:start position:0% +sequence thing gets played back to the +cortex so you know the cortex it sort of + + align:start position:0% +cortex so you know the cortex it sort of + + + align:start position:0% +cortex so you know the cortex it sort of +knows you know if it has these sort of + + align:start position:0% +knows you know if it has these sort of + + + align:start position:0% +knows you know if it has these sort of +discrete states but doesn't necessarily + + align:start position:0% +discrete states but doesn't necessarily + + + align:start position:0% +discrete states but doesn't necessarily +know what the cause of correlations + + align:start position:0% +know what the cause of correlations + + + align:start position:0% +know what the cause of correlations +might be what happens next + + align:start position:0% +might be what happens next + + + align:start position:0% +might be what happens next +it doesn't necessarily know what happens + + align:start position:0% +it doesn't necessarily know what happens + + + align:start position:0% +it doesn't necessarily know what happens +next it knows what happened hippocampus + + align:start position:0% +next it knows what happened hippocampus + + + align:start position:0% +next it knows what happened hippocampus +knows what happened next it has lots of + + align:start position:0% +knows what happened next it has lots of + + + align:start position:0% +knows what happened next it has lots of +instances of that though well I saw you + + align:start position:0% +instances of that though well I saw you + + + align:start position:0% +instances of that though well I saw you +know you know I saw red light what + + align:start position:0% +know you know I saw red light what + + + align:start position:0% +know you know I saw red light what +happens next + + align:start position:0% +happens next + + + align:start position:0% +happens next +oh yeah you know I saw red light and all + + align:start position:0% +oh yeah you know I saw red light and all + + + align:start position:0% +oh yeah you know I saw red light and all +the cars stopped okay that's great + + align:start position:0% +the cars stopped okay that's great + + + align:start position:0% +the cars stopped okay that's great +you know if I'm just the cortex that's + + align:start position:0% +you know if I'm just the cortex that's + + + align:start position:0% +you know if I'm just the cortex that's +what I learned all the cars stop if I'm + + align:start position:0% +what I learned all the cars stop if I'm + + + align:start position:0% +what I learned all the cars stop if I'm +hippocampus I'm a little bit smarter + + align:start position:0% +hippocampus I'm a little bit smarter + + + align:start position:0% +hippocampus I'm a little bit smarter +than that you know you know last Tuesday + + align:start position:0% +than that you know you know last Tuesday + + + align:start position:0% +than that you know you know last Tuesday +I was there there's a red light and all + + align:start position:0% +I was there there's a red light and all + + + align:start position:0% +I was there there's a red light and all +the cars except for these cyclists man + + align:start position:0% +the cars except for these cyclists man + + + align:start position:0% +the cars except for these cyclists man +they didn't stop they just kept on going + + align:start position:0% +they didn't stop they just kept on going + + + align:start position:0% +they didn't stop they just kept on going +so wait a minute so this there's a rule + + align:start position:0% +so wait a minute so this there's a rule + + + align:start position:0% +so wait a minute so this there's a rule +you know red light cars stop bicycles + + align:start position:0% +you know red light cars stop bicycles + + + align:start position:0% +you know red light cars stop bicycles +don't stop so you were fine right you + + align:start position:0% +don't stop so you were fine right you + + + align:start position:0% +don't stop so you were fine right you +have to refine these various what appear + + align:start position:0% +have to refine these various what appear + + + align:start position:0% +have to refine these various what appear +to be simple rules prefrontal cortex + + align:start position:0% +to be simple rules prefrontal cortex + + + align:start position:0% +to be simple rules prefrontal cortex +often that's actually used in an example + + align:start position:0% +often that's actually used in an example + + + align:start position:0% +often that's actually used in an example +how do you use the prefrontal cortex Oh + + align:start position:0% +how do you use the prefrontal cortex Oh + + + align:start position:0% +how do you use the prefrontal cortex Oh +red light means stop green light means + + align:start position:0% +red light means stop green light means + + + align:start position:0% +red light means stop green light means +go that's great except in the real world + + align:start position:0% +go that's great except in the real world + + + align:start position:0% +go that's great except in the real world +that rule is too simple it has to be + + align:start position:0% +that rule is too simple it has to be + + + align:start position:0% +that rule is too simple it has to be +refined has to be refined based on your + + align:start position:0% +refined has to be refined based on your + + + align:start position:0% +refined has to be refined based on your +particular experience in fact if you're + + align:start position:0% +particular experience in fact if you're + + + align:start position:0% +particular experience in fact if you're +really sophisticated red light means + + align:start position:0% +really sophisticated red light means + + + align:start position:0% +really sophisticated red light means +cars except for cabbies will stop right + + align:start position:0% +cars except for cabbies will stop right + + + align:start position:0% +cars except for cabbies will stop right +if I see a cabbie guarantee that guy's + + align:start position:0% +if I see a cabbie guarantee that guy's + + + align:start position:0% +if I see a cabbie guarantee that guy's +not gonna stop using an accelerator + + align:start position:0% +not gonna stop using an accelerator + + + align:start position:0% +not gonna stop using an accelerator +right it's a + + align:start position:0% +right it's a + + + align:start position:0% +right it's a +and that's kind of information that's + + align:start position:0% +and that's kind of information that's + + + align:start position:0% +and that's kind of information that's +what the hippocampus has and so you + + align:start position:0% +what the hippocampus has and so you + + + align:start position:0% +what the hippocampus has and so you +imagine that's what's going on neocortex + + align:start position:0% +imagine that's what's going on neocortex + + + align:start position:0% +imagine that's what's going on neocortex +in each one of these slow oscillations + + align:start position:0% +in each one of these slow oscillations + + + align:start position:0% +in each one of these slow oscillations +saying red light and they pick Amba says + + align:start position:0% +saying red light and they pick Amba says + + + align:start position:0% +saying red light and they pick Amba says +oh yeah okay cars stop red light again + + align:start position:0% +oh yeah okay cars stop red light again + + + align:start position:0% +oh yeah okay cars stop red light again +oh there was a bicycle thing bicycles + + align:start position:0% +oh there was a bicycle thing bicycles + + + align:start position:0% +oh there was a bicycle thing bicycles +continue to go red light and that was + + align:start position:0% +continue to go red light and that was + + + align:start position:0% +continue to go red light and that was +the cabbie incident so now you have all + + align:start position:0% +the cabbie incident so now you have all + + + align:start position:0% +the cabbie incident so now you have all +these different these sort of causal + + align:start position:0% +these different these sort of causal + + + align:start position:0% +these different these sort of causal +sequences that are being expressed back + + align:start position:0% +sequences that are being expressed back + + + align:start position:0% +sequences that are being expressed back +to the neocortex presumably in order to + + align:start position:0% +to the neocortex presumably in order to + + + align:start position:0% +to the neocortex presumably in order to +establish this this more comprehensive + + align:start position:0% +establish this this more comprehensive + + + align:start position:0% +establish this this more comprehensive +consolidated model of real-world traffic + + align:start position:0% +consolidated model of real-world traffic + + + align:start position:0% +consolidated model of real-world traffic +lights rather than the cartoon traffic + + align:start position:0% +lights rather than the cartoon traffic + + + align:start position:0% +lights rather than the cartoon traffic +lights and so that would be the idea + + align:start position:0% +lights and so that would be the idea + + + align:start position:0% +lights and so that would be the idea +what's going on during asleep now during + + align:start position:0% +what's going on during asleep now during + + + align:start position:0% +what's going on during asleep now during +quiet wakefulness you can think of the + + align:start position:0% +quiet wakefulness you can think of the + + + align:start position:0% +quiet wakefulness you can think of the +same sort of idea and that is that + + align:start position:0% +same sort of idea and that is that + + + align:start position:0% +same sort of idea and that is that +you're kind of evaluating evaluating + + align:start position:0% +you're kind of evaluating evaluating + + + align:start position:0% +you're kind of evaluating evaluating +multiple calls of contingencies each of + + align:start position:0% +multiple calls of contingencies each of + + + align:start position:0% +multiple calls of contingencies each of +which might be expressible as a simple + + align:start position:0% +which might be expressible as a simple + + + align:start position:0% +which might be expressible as a simple +rule but might also be experienced as + + align:start position:0% +rule but might also be experienced as + + + align:start position:0% +rule but might also be experienced as +distinct variations of that rule and the + + align:start position:0% +distinct variations of that rule and the + + + align:start position:0% +distinct variations of that rule and the +ideas okay do we use the rule or do we + + align:start position:0% +ideas okay do we use the rule or do we + + + align:start position:0% +ideas okay do we use the rule or do we +use the exceptions or how do we actually + + align:start position:0% +use the exceptions or how do we actually + + + align:start position:0% +use the exceptions or how do we actually +you know how do we refine the rule based + + align:start position:0% +you know how do we refine the rule based + + + align:start position:0% +you know how do we refine the rule based +upon these different instances or + + align:start position:0% +upon these different instances or + + + align:start position:0% +upon these different instances or +exceptions so you can think about that + + align:start position:0% +exceptions so you can think about that + + + align:start position:0% +exceptions so you can think about that +is refining the rule that's like the + + align:start position:0% +is refining the rule that's like the + + + align:start position:0% +is refining the rule that's like the +learning sign applying the rule that's + + align:start position:0% +learning sign applying the rule that's + + + align:start position:0% +learning sign applying the rule that's +the sort of a memory of decision-making + + align:start position:0% +the sort of a memory of decision-making + + + align:start position:0% +the sort of a memory of decision-making +aside so you can think about during + + align:start position:0% +aside so you can think about during + + + align:start position:0% +aside so you can think about during +quiet wakefulness this reactivation + + align:start position:0% +quiet wakefulness this reactivation + + + align:start position:0% +quiet wakefulness this reactivation +being used in the service of actual + + align:start position:0% +being used in the service of actual + + + align:start position:0% +being used in the service of actual +learning or in decision-making and so + + align:start position:0% +learning or in decision-making and so + + + align:start position:0% +learning or in decision-making and so +again you're at the paper and one of the + + align:start position:0% +again you're at the paper and one of the + + + align:start position:0% +again you're at the paper and one of the +things that we had discovered in + + align:start position:0% +things that we had discovered in + + + align:start position:0% +things that we had discovered in +interesting about reactivation during + + align:start position:0% +interesting about reactivation during + + + align:start position:0% +interesting about reactivation during +quiet wakefulness was that when animals + + align:start position:0% +quiet wakefulness was that when animals + + + align:start position:0% +quiet wakefulness was that when animals +stop after running on a track they do + + align:start position:0% +stop after running on a track they do + + + align:start position:0% +stop after running on a track they do +reactivate sequences this is raw data + + align:start position:0% +reactivate sequences this is raw data + + + align:start position:0% +reactivate sequences this is raw data +animal running from left to right and + + align:start position:0% +animal running from left to right and + + + align:start position:0% +animal running from left to right and +then stopping for a long period of time + + align:start position:0% +then stopping for a long period of time + + + align:start position:0% +then stopping for a long period of time +and you can see activity there these + + align:start position:0% +and you can see activity there these + + + align:start position:0% +and you can see activity there these +bursts of activity you blow things + + align:start position:0% +bursts of activity you blow things + + + align:start position:0% +bursts of activity you blow things +things up these these sharp wave ripples + + align:start position:0% +things up these these sharp wave ripples + + + align:start position:0% +things up these these sharp wave ripples +last about half a second or so so you + + align:start position:0% +last about half a second or so so you + + + align:start position:0% +last about half a second or so so you +see a burst of activity you see these + + align:start position:0% +see a burst of activity you see these + + + align:start position:0% +see a burst of activity you see these +place cell sequences in this case the + + align:start position:0% +place cell sequences in this case the + + + align:start position:0% +place cell sequences in this case the +sequence actually runs in time reversed + + align:start position:0% +sequence actually runs in time reversed + + + align:start position:0% +sequence actually runs in time reversed +fashion so in this case you know time + + align:start position:0% +fashion so in this case you know time + + + align:start position:0% +fashion so in this case you know time +reverse fashion just doesn't this + + align:start position:0% +reverse fashion just doesn't this + + + align:start position:0% +reverse fashion just doesn't this +seemed like planning or decision-making + + align:start position:0% +seemed like planning or decision-making + + + align:start position:0% +seemed like planning or decision-making +it may be a valuation of temporal + + align:start position:0% +it may be a valuation of temporal + + + align:start position:0% +it may be a valuation of temporal +correlations that might be relevant to + + align:start position:0% +correlations that might be relevant to + + + align:start position:0% +correlations that might be relevant to +behavior and learning but what would a + + align:start position:0% +behavior and learning but what would a + + + align:start position:0% +behavior and learning but what would a +reverse sequence actually have to do + + align:start position:0% +reverse sequence actually have to do + + + align:start position:0% +reverse sequence actually have to do +with with you know spatial learning and + + align:start position:0% +with with you know spatial learning and + + + align:start position:0% +with with you know spatial learning and +memory well that actually came from the + + align:start position:0% +memory well that actually came from the + + + align:start position:0% +memory well that actually came from the +insight into how this might be used came + + align:start position:0% +insight into how this might be used came + + + align:start position:0% +insight into how this might be used came +from computational models in fact + + align:start position:0% +from computational models in fact + + + align:start position:0% +from computational models in fact +computational models that the postdoc in + + align:start position:0% +computational models that the postdoc in + + + align:start position:0% +computational models that the postdoc in +this case Dave foster who made this + + align:start position:0% +this case Dave foster who made this + + + align:start position:0% +this case Dave foster who made this +discovery had used in his doctoral work + + align:start position:0% +discovery had used in his doctoral work + + + align:start position:0% +discovery had used in his doctoral work +where he was actually building model + + align:start position:0% +where he was actually building model + + + align:start position:0% +where he was actually building model +reinforcement learning models with + + align:start position:0% +reinforcement learning models with + + + align:start position:0% +reinforcement learning models with +spatial navigation and one of the + + align:start position:0% +spatial navigation and one of the + + + align:start position:0% +spatial navigation and one of the +problems in reinforcement learning is + + align:start position:0% +problems in reinforcement learning is + + + align:start position:0% +problems in reinforcement learning is +that reinforcement often comes after + + align:start position:0% +that reinforcement often comes after + + + align:start position:0% +that reinforcement often comes after +you've actually carried out the steps + + align:start position:0% +you've actually carried out the steps + + + align:start position:0% +you've actually carried out the steps +that lead up to it in other words you + + align:start position:0% +that lead up to it in other words you + + + align:start position:0% +that lead up to it in other words you +walk from left to right you get rewarded + + align:start position:0% +walk from left to right you get rewarded + + + align:start position:0% +walk from left to right you get rewarded +when you get here what you want to know + + align:start position:0% +when you get here what you want to know + + + align:start position:0% +when you get here what you want to know +is not just this is where the reward is + + align:start position:0% +is not just this is where the reward is + + + align:start position:0% +is not just this is where the reward is +what you really want to know is what + + align:start position:0% +what you really want to know is what + + + align:start position:0% +what you really want to know is what +were the what are the things that + + align:start position:0% +were the what are the things that + + + align:start position:0% +were the what are the things that +actually led up to that notice I want to + + align:start position:0% +actually led up to that notice I want to + + + align:start position:0% +actually led up to that notice I want to +take credit reward value and I want to + + align:start position:0% +take credit reward value and I want to + + + align:start position:0% +take credit reward value and I want to +spread it backward in time to place + + align:start position:0% +spread it backward in time to place + + + align:start position:0% +spread it backward in time to place +value on the things that predict or led + + align:start position:0% +value on the things that predict or led + + + align:start position:0% +value on the things that predict or led +up to reward the so called temporal + + align:start position:0% +up to reward the so called temporal + + + align:start position:0% +up to reward the so called temporal +credit assignment problem how do I give + + align:start position:0% +credit assignment problem how do I give + + + align:start position:0% +credit assignment problem how do I give +credit to things that actually lead up + + align:start position:0% +credit to things that actually lead up + + + align:start position:0% +credit to things that actually lead up +to a predict reward and thinking about + + align:start position:0% +to a predict reward and thinking about + + + align:start position:0% +to a predict reward and thinking about +how you might solve the temporal credit + + align:start position:0% +how you might solve the temporal credit + + + align:start position:0% +how you might solve the temporal credit +assignment problem this reverse + + align:start position:0% +assignment problem this reverse + + + align:start position:0% +assignment problem this reverse +reactivation actually has the capacity + + align:start position:0% +reactivation actually has the capacity + + + align:start position:0% +reactivation actually has the capacity +to to solve that problem in one step + + align:start position:0% +to to solve that problem in one step + + + align:start position:0% +to to solve that problem in one step +if you imagine when animal gets to the + + align:start position:0% +if you imagine when animal gets to the + + + align:start position:0% +if you imagine when animal gets to the +end gets some reward and if now at that + + align:start position:0% +end gets some reward and if now at that + + + align:start position:0% +end gets some reward and if now at that +point I pair the delivery of a rewards + + align:start position:0% +point I pair the delivery of a rewards + + + align:start position:0% +point I pair the delivery of a rewards +signal which I will indicate here is + + align:start position:0% +signal which I will indicate here is + + + align:start position:0% +signal which I will indicate here is +this is a cartoon suggesting this is + + align:start position:0% +this is a cartoon suggesting this is + + + align:start position:0% +this is a cartoon suggesting this is +dopamine or reward signal and I'm gonna + + align:start position:0% +dopamine or reward signal and I'm gonna + + + align:start position:0% +dopamine or reward signal and I'm gonna +pair that with the reverse sequence and + + align:start position:0% +pair that with the reverse sequence and + + + align:start position:0% +pair that with the reverse sequence and +now you can think of the Association + + align:start position:0% +now you can think of the Association + + + align:start position:0% +now you can think of the Association +this is my current location this is way + + align:start position:0% +this is my current location this is way + + + align:start position:0% +this is my current location this is way +back where I started from + + align:start position:0% +back where I started from + + + align:start position:0% +back where I started from +current location gets paired with strong + + align:start position:0% +current location gets paired with strong + + + align:start position:0% +current location gets paired with strong +reward remote location gets paired with + + align:start position:0% +reward remote location gets paired with + + + align:start position:0% +reward remote location gets paired with +low reward so this association will + + align:start position:0% +low reward so this association will + + + align:start position:0% +low reward so this association will +essentially solve will convolve this + + align:start position:0% +essentially solve will convolve this + + + align:start position:0% +essentially solve will convolve this +sort of this reward discrete reward + + align:start position:0% +sort of this reward discrete reward + + + align:start position:0% +sort of this reward discrete reward +impulse function will turn it into this + + align:start position:0% +impulse function will turn it into this + + + align:start position:0% +impulse function will turn it into this +continuous graded + + align:start position:0% +continuous graded + + + align:start position:0% +continuous graded +sort of monotonic reward gradient + + align:start position:0% +sort of monotonic reward gradient + + + align:start position:0% +sort of monotonic reward gradient +function translating this into this + + align:start position:0% +function translating this into this + + + align:start position:0% +function translating this into this +essentially in one step so the thinking + + align:start position:0% +essentially in one step so the thinking + + + align:start position:0% +essentially in one step so the thinking +is hey animals are actually using this + + align:start position:0% +is hey animals are actually using this + + + align:start position:0% +is hey animals are actually using this +to learn and they're using it to solve + + align:start position:0% +to learn and they're using it to solve + + + align:start position:0% +to learn and they're using it to solve +the temporal credit assignment problem + + align:start position:0% +the temporal credit assignment problem + + + align:start position:0% +the temporal credit assignment problem +in a way that would be that would be + + align:start position:0% +in a way that would be that would be + + + align:start position:0% +in a way that would be that would be +important for general reinforcement + + align:start position:0% +important for general reinforcement + + + align:start position:0% +important for general reinforcement +learning now I won't go into so we + + align:start position:0% +learning now I won't go into so we + + + align:start position:0% +learning now I won't go into so we +actually did this experiment recorded + + align:start position:0% +actually did this experiment recorded + + + align:start position:0% +actually did this experiment recorded +from the reward area the VTA + + align:start position:0% +from the reward area the VTA + + + align:start position:0% +from the reward area the VTA +and the hippocampus and indeed during + + align:start position:0% +and the hippocampus and indeed during + + + align:start position:0% +and the hippocampus and indeed during +these reactivation events you see the + + align:start position:0% +these reactivation events you see the + + + align:start position:0% +these reactivation events you see the +pairing of this reward signalling and + + align:start position:0% +pairing of this reward signalling and + + + align:start position:0% +pairing of this reward signalling and +it's not only do you see the pairing of + + align:start position:0% +it's not only do you see the pairing of + + + align:start position:0% +it's not only do you see the pairing of +the reward signaling but you find + + align:start position:0% +the reward signaling but you find + + + align:start position:0% +the reward signaling but you find +pairing of the reward signaling in which + + align:start position:0% +pairing of the reward signaling in which + + + align:start position:0% +pairing of the reward signaling in which +the precise firing of reward of source + + align:start position:0% +the precise firing of reward of source + + + align:start position:0% +the precise firing of reward of source +signals map on to the delivery of + + align:start position:0% +signals map on to the delivery of + + + align:start position:0% +signals map on to the delivery of +rewards at goal locations so it's not + + align:start position:0% +rewards at goal locations so it's not + + + align:start position:0% +rewards at goal locations so it's not +just certain sequences are good others + + align:start position:0% +just certain sequences are good others + + + align:start position:0% +just certain sequences are good others +are bad it's that there are certain + + align:start position:0% +are bad it's that there are certain + + + align:start position:0% +are bad it's that there are certain +locations along the sequence that have + + align:start position:0% +locations along the sequence that have + + + align:start position:0% +locations along the sequence that have +differential reward value so there's a + + align:start position:0% +differential reward value so there's a + + + align:start position:0% +differential reward value so there's a +mapping of relative reward to location + + align:start position:0% +mapping of relative reward to location + + + align:start position:0% +mapping of relative reward to location +and that if you look at this while + + align:start position:0% +and that if you look at this while + + + align:start position:0% +and that if you look at this while +animals are actually performing a task + + align:start position:0% +animals are actually performing a task + + + align:start position:0% +animals are actually performing a task +you can see biases in these sequences + + align:start position:0% +you can see biases in these sequences + + + align:start position:0% +you can see biases in these sequences +that correspond to planning so both of + + align:start position:0% +that correspond to planning so both of + + + align:start position:0% +that correspond to planning so both of +these elements of sequence reactivation + + align:start position:0% +these elements of sequence reactivation + + + align:start position:0% +these elements of sequence reactivation +this was some work by Dave Foster or he + + align:start position:0% +this was some work by Dave Foster or he + + + align:start position:0% +this was some work by Dave Foster or he +looked at an animal that has to just + + align:start position:0% +looked at an animal that has to just + + + align:start position:0% +looked at an animal that has to just +forge and find a location space when + + align:start position:0% +forge and find a location space when + + + align:start position:0% +forge and find a location space when +animals are searching for a location and + + align:start position:0% +animals are searching for a location and + + + align:start position:0% +animals are searching for a location and +you look at these reactivated sequences + + align:start position:0% +you look at these reactivated sequences + + + align:start position:0% +you look at these reactivated sequences +it turns out that reactivated sequences + + align:start position:0% +it turns out that reactivated sequences + + + align:start position:0% +it turns out that reactivated sequences +tend to be directed toward the locations + + align:start position:0% +tend to be directed toward the locations + + + align:start position:0% +tend to be directed toward the locations +where the animal thinks the goal might + + align:start position:0% +where the animal thinks the goal might + + + align:start position:0% +where the animal thinks the goal might +be so it's sort of thinking about things + + align:start position:0% +be so it's sort of thinking about things + + + align:start position:0% +be so it's sort of thinking about things +that would lead to reward so both sides + + align:start position:0% +that would lead to reward so both sides + + + align:start position:0% +that would lead to reward so both sides +of this kind of sequential computation + + align:start position:0% +of this kind of sequential computation + + + align:start position:0% +of this kind of sequential computation +seem to be expressed in the hippocampus + + align:start position:0% +seem to be expressed in the hippocampus + + + align:start position:0% +seem to be expressed in the hippocampus +Co expressional with reward during + + align:start position:0% +Co expressional with reward during + + + align:start position:0% +Co expressional with reward during +evaluation or learning the expression + + align:start position:0% +evaluation or learning the expression + + + align:start position:0% +evaluation or learning the expression +during reward directed behavior in the + + align:start position:0% +during reward directed behavior in the + + + align:start position:0% +during reward directed behavior in the +service of planning a decision-making + + align:start position:0% +service of planning a decision-making + + + align:start position:0% +service of planning a decision-making +and then finally round was done this is + + align:start position:0% +and then finally round was done this is + + + align:start position:0% +and then finally round was done this is +the paper that we had that we had that + + align:start position:0% +the paper that we had that we had that + + + align:start position:0% +the paper that we had that we had that +you had read is just looking at the + + align:start position:0% +you had read is just looking at the + + + align:start position:0% +you had read is just looking at the +structure of these reward sequences on + + align:start position:0% +structure of these reward sequences on + + + align:start position:0% +structure of these reward sequences on +long tracks and the thing the sort of + + align:start position:0% +long tracks and the thing the sort of + + + align:start position:0% +long tracks and the thing the sort of +the most salient point that came out of + + align:start position:0% +the most salient point that came out of + + + align:start position:0% +the most salient point that came out of +this + + align:start position:0% +this + + + align:start position:0% +this +paper is that this shirt this the + + align:start position:0% +paper is that this shirt this the + + + align:start position:0% +paper is that this shirt this the +phenomena of sharp wave ripple + + align:start position:0% +phenomena of sharp wave ripple + + + align:start position:0% +phenomena of sharp wave ripple +sequential activation that corresponds + + align:start position:0% +sequential activation that corresponds + + + align:start position:0% +sequential activation that corresponds +to these theta sequences when animals + + align:start position:0% +to these theta sequences when animals + + + align:start position:0% +to these theta sequences when animals +are sitting quietly over the course of + + align:start position:0% +are sitting quietly over the course of + + + align:start position:0% +are sitting quietly over the course of +these longer upstate like events takes + + align:start position:0% +these longer upstate like events takes + + + align:start position:0% +these longer upstate like events takes +the form of bursts of sharp wave ripples + + align:start position:0% +the form of bursts of sharp wave ripples + + + align:start position:0% +the form of bursts of sharp wave ripples +or sequences of these short sequences so + + align:start position:0% +or sequences of these short sequences so + + + align:start position:0% +or sequences of these short sequences so +there's this compositional notion that + + align:start position:0% +there's this compositional notion that + + + align:start position:0% +there's this compositional notion that +you form long sequences out of little + + align:start position:0% +you form long sequences out of little + + + align:start position:0% +you form long sequences out of little +short sequences and there the question + + align:start position:0% +short sequences and there the question + + + align:start position:0% +short sequences and there the question +is how do you actually put these short + + align:start position:0% +is how do you actually put these short + + + align:start position:0% +is how do you actually put these short +sequences together and why would you + + align:start position:0% +sequences together and why would you + + + align:start position:0% +sequences together and why would you +actually have a why would you have a + + align:start position:0% +actually have a why would you have a + + + align:start position:0% +actually have a why would you have a +representation that has this kind of + + align:start position:0% +representation that has this kind of + + + align:start position:0% +representation that has this kind of +compositional structure or you can it's + + align:start position:0% +compositional structure or you can it's + + + align:start position:0% +compositional structure or you can it's +the Lego block kind of idea where I can + + align:start position:0% +the Lego block kind of idea where I can + + + align:start position:0% +the Lego block kind of idea where I can +put together sequences from these + + align:start position:0% +put together sequences from these + + + align:start position:0% +put together sequences from these +fundamental ease more sort of elemental + + align:start position:0% +fundamental ease more sort of elemental + + + align:start position:0% +fundamental ease more sort of elemental +sequential units and this is just I + + align:start position:0% +sequential units and this is just I + + + align:start position:0% +sequential units and this is just I +don't show the movie but if I actually + + align:start position:0% +don't show the movie but if I actually + + + align:start position:0% +don't show the movie but if I actually +zoom in on one of those sequences that + + align:start position:0% +zoom in on one of those sequences that + + + align:start position:0% +zoom in on one of those sequences that +in that particular instance with animal + + align:start position:0% +in that particular instance with animal + + + align:start position:0% +in that particular instance with animal +stop you can see that longer there's a + + align:start position:0% +stop you can see that longer there's a + + + align:start position:0% +stop you can see that longer there's a +longer reactivated sequence that + + align:start position:0% +longer reactivated sequence that + + + align:start position:0% +longer reactivated sequence that +actually takes the form of for shorter + + align:start position:0% +actually takes the form of for shorter + + + align:start position:0% +actually takes the form of for shorter +sequences that's how that's how long + + align:start position:0% +sequences that's how that's how long + + + align:start position:0% +sequences that's how that's how long +sequences are being evaluated and I + + align:start position:0% +sequences are being evaluated and I + + + align:start position:0% +sequences are being evaluated and I +can't show that and one interesting + + align:start position:0% +can't show that and one interesting + + + align:start position:0% +can't show that and one interesting +thing about this was that if you look at + + align:start position:0% +thing about this was that if you look at + + + align:start position:0% +thing about this was that if you look at +these different sequences at different + + align:start position:0% +these different sequences at different + + + align:start position:0% +these different sequences at different +lengths different lengths shorter + + align:start position:0% +lengths different lengths shorter + + + align:start position:0% +lengths different lengths shorter +sequence longer sequences they all seem + + align:start position:0% +sequence longer sequences they all seem + + + align:start position:0% +sequence longer sequences they all seem +to have a fixed velocity and that is + + align:start position:0% +to have a fixed velocity and that is + + + align:start position:0% +to have a fixed velocity and that is +this is kind of a fixed where it is the + + align:start position:0% +this is kind of a fixed where it is the + + + align:start position:0% +this is kind of a fixed where it is the +speed of thought so that there is some + + align:start position:0% +speed of thought so that there is some + + + align:start position:0% +speed of thought so that there is some +fixed constraint that that that + + align:start position:0% +fixed constraint that that that + + + align:start position:0% +fixed constraint that that that +evaluating you know further out and the + + align:start position:0% +evaluating you know further out and the + + + align:start position:0% +evaluating you know further out and the +future simply takes more time and so + + align:start position:0% +future simply takes more time and so + + + align:start position:0% +future simply takes more time and so +that suggests that there's an + + align:start position:0% +that suggests that there's an + + + align:start position:0% +that suggests that there's an +interesting + + align:start position:0% +interesting + + + align:start position:0% +interesting +there's an interesting constraining + + align:start position:0% +there's an interesting constraining + + + align:start position:0% +there's an interesting constraining +capacity for extended evaluation that + + align:start position:0% +capacity for extended evaluation that + + + align:start position:0% +capacity for extended evaluation that +comes in the form of these like these + + align:start position:0% +comes in the form of these like these + + + align:start position:0% +comes in the form of these like these +these oscillatory modes or the slow + + align:start position:0% +these oscillatory modes or the slow + + + align:start position:0% +these oscillatory modes or the slow +oscillation longer or slower frequencies + + align:start position:0% +oscillation longer or slower frequencies + + + align:start position:0% +oscillation longer or slower frequencies +give you essentially more time longer + + align:start position:0% +give you essentially more time longer + + + align:start position:0% +give you essentially more time longer +sequences and that potentially if you + + align:start position:0% +sequences and that potentially if you + + + align:start position:0% +sequences and that potentially if you +want to go even longer you might + + align:start position:0% +want to go even longer you might + + + align:start position:0% +want to go even longer you might +actually even link sequences across + + align:start position:0% +actually even link sequences across + + + align:start position:0% +actually even link sequences across +subsequent cycles just as you as you + + align:start position:0% +subsequent cycles just as you as you + + + align:start position:0% +subsequent cycles just as you as you +could do across successive sharp wave + + align:start position:0% +could do across successive sharp wave + + + align:start position:0% +could do across successive sharp wave +ripples you might be able to do across + + align:start position:0% +ripples you might be able to do across + + + align:start position:0% +ripples you might be able to do across +successive slow ways so the idea that + + align:start position:0% +successive slow ways so the idea that + + + align:start position:0% +successive slow ways so the idea that +you have these oscillations that you can + + align:start position:0% +you have these oscillations that you can + + + align:start position:0% +you have these oscillations that you can +link or couple sequences across + + align:start position:0% +link or couple sequences across + + + align:start position:0% +link or couple sequences across +different cycles of these oscillations + + align:start position:0% +different cycles of these oscillations + + + align:start position:0% +different cycles of these oscillations +that you have oscillation of different + + align:start position:0% +that you have oscillation of different + + + align:start position:0% +that you have oscillation of different +frequencies suggests that that's the + + align:start position:0% +frequencies suggests that that's the + + + align:start position:0% +frequencies suggests that that's the +moat that this is the mechanism it's a + + align:start position:0% +moat that this is the mechanism it's a + + + align:start position:0% +moat that this is the mechanism it's a +cop + + align:start position:0% +cop + + + align:start position:0% +cop +no mechanism for sequences that are + + align:start position:0% +no mechanism for sequences that are + + + align:start position:0% +no mechanism for sequences that are +nested within oscillations by combining + + align:start position:0% +nested within oscillations by combining + + + align:start position:0% +nested within oscillations by combining +these oscillations you can construct + + align:start position:0% +these oscillations you can construct + + + align:start position:0% +these oscillations you can construct +these sequences in ways that presumably + + align:start position:0% +these sequences in ways that presumably + + + align:start position:0% +these sequences in ways that presumably +contribute to cognition but we don't so + + align:start position:0% +contribute to cognition but we don't so + + + align:start position:0% +contribute to cognition but we don't so +we now kind of see how things are + + align:start position:0% +we now kind of see how things are + + + align:start position:0% +we now kind of see how things are +structured and now the question is can + + align:start position:0% +structured and now the question is can + + + align:start position:0% +structured and now the question is can +we actually manipulate it so that would + + align:start position:0% +we actually manipulate it so that would + + + align:start position:0% +we actually manipulate it so that would +real that's really the challenge seeing + + align:start position:0% +real that's really the challenge seeing + + + align:start position:0% +real that's really the challenge seeing +the compositional structure having so + + align:start position:0% +the compositional structure having so + + + align:start position:0% +the compositional structure having so +demonstrated potential access the + + align:start position:0% +demonstrated potential access the + + + align:start position:0% +demonstrated potential access the +ability to bias content to core to bias + + align:start position:0% +ability to bias content to core to bias + + + align:start position:0% +ability to bias content to core to bias +the you know the structure when things + + align:start position:0% +the you know the structure when things + + + align:start position:0% +the you know the structure when things +occur what actually occurs now I think + + align:start position:0% +occur what actually occurs now I think + + + align:start position:0% +occur what actually occurs now I think +the capacity exists to essentially + + align:start position:0% +the capacity exists to essentially + + + align:start position:0% +the capacity exists to essentially +engineer the sequences themselves and + + align:start position:0% +engineer the sequences themselves and + + + align:start position:0% +engineer the sequences themselves and +that is that during the sleeper quiet + + align:start position:0% +that is that during the sleeper quiet + + + align:start position:0% +that is that during the sleeper quiet +wakeful States get animals to think + + align:start position:0% +wakeful States get animals to think + + + align:start position:0% +wakeful States get animals to think +about things that they have not actually + + align:start position:0% +about things that they have not actually + + + align:start position:0% +about things that they have not actually +experienced and test the hypothesis this + + align:start position:0% +experienced and test the hypothesis this + + + align:start position:0% +experienced and test the hypothesis this +is what actually this is what animals + + align:start position:0% +is what actually this is what animals + + + align:start position:0% +is what actually this is what animals +are using to construct these models to + + align:start position:0% +are using to construct these models to + + + align:start position:0% +are using to construct these models to +essentially tinker with the blocks of + + align:start position:0% +essentially tinker with the blocks of + + + align:start position:0% +essentially tinker with the blocks of +memory and cognition and then finally + + align:start position:0% +memory and cognition and then finally + + + align:start position:0% +memory and cognition and then finally +just pointing out its interested these + + align:start position:0% +just pointing out its interested these + + + align:start position:0% +just pointing out its interested these +ripple sequences same space and time + + align:start position:0% +ripple sequences same space and time + + + align:start position:0% +ripple sequences same space and time +scales theta sequences so again it's + + align:start position:0% +scales theta sequences so again it's + + + align:start position:0% +scales theta sequences so again it's +suggesting this is the fundamental unit + + align:start position:0% +suggesting this is the fundamental unit + + + align:start position:0% +suggesting this is the fundamental unit +it's not unique to the hippocampus + + align:start position:0% +it's not unique to the hippocampus + + + align:start position:0% +it's not unique to the hippocampus +essentially any brain system could + + align:start position:0% +essentially any brain system could + + + align:start position:0% +essentially any brain system could +express this kind of structure using + + align:start position:0% +express this kind of structure using + + + align:start position:0% +express this kind of structure using +that simple model where you see ramps + + align:start position:0% +that simple model where you see ramps + + + align:start position:0% +that simple model where you see ramps +and you see oscillations you're gonna + + align:start position:0% +and you see oscillations you're gonna + + + align:start position:0% +and you see oscillations you're gonna +get sequences and this capacity is + + align:start position:0% +get sequences and this capacity is + + + align:start position:0% +get sequences and this capacity is +something that probably is broadly + + align:start position:0% +something that probably is broadly + + + align:start position:0% +something that probably is broadly +expressed and enjoyed by different brain + + align:start position:0% +expressed and enjoyed by different brain + + + align:start position:0% +expressed and enjoyed by different brain +areas so there you go + + align:start position:0% + + + + align:start position:0% + +you \ No newline at end of file diff --git a/gF4Mkkhyz1Q.txt b/gF4Mkkhyz1Q.txt new file mode 100644 index 0000000000000000000000000000000000000000..18af013756bd823d593e5054cdf084589abc1e04 --- /dev/null +++ b/gF4Mkkhyz1Q.txt @@ -0,0 +1,13635 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT OpenCourseWare continue to + + align:start position:0% +will help MIT OpenCourseWare continue to + + + align:start position:0% +will help MIT OpenCourseWare continue to +offer high quality educational resources + + align:start position:0% +offer high quality educational resources + + + align:start position:0% +offer high quality educational resources +for free + + align:start position:0% +for free + + + align:start position:0% +for free +to make a donation or to view additional + + align:start position:0% +to make a donation or to view additional + + + align:start position:0% +to make a donation or to view additional +materials from hundreds of MIT courses + + align:start position:0% +materials from hundreds of MIT courses + + + align:start position:0% +materials from hundreds of MIT courses +visit MIT opencourseware at ocw.mit.edu + + align:start position:0% + + + + align:start position:0% + +okay so today I'm going to talk about + + align:start position:0% +okay so today I'm going to talk about + + + align:start position:0% +okay so today I'm going to talk about +mast taproot and graft route and these + + align:start position:0% +mast taproot and graft route and these + + + align:start position:0% +mast taproot and graft route and these +are pretty cool new ideas in Bitcoin + + align:start position:0% +are pretty cool new ideas in Bitcoin + + + align:start position:0% +are pretty cool new ideas in Bitcoin +they're not really production-ready + + align:start position:0% +they're not really production-ready + + + align:start position:0% +they're not really production-ready +they're still sort of ideas but it's + + align:start position:0% +they're still sort of ideas but it's + + + align:start position:0% +they're still sort of ideas but it's +kind of neat to look at the future + + align:start position:0% +kind of neat to look at the future + + + align:start position:0% +kind of neat to look at the future +directions of how people are thinking + + align:start position:0% +directions of how people are thinking + + + align:start position:0% +directions of how people are thinking +about improving these protocols so we're + + align:start position:0% +about improving these protocols so we're + + + align:start position:0% +about improving these protocols so we're +going to talk about new types of scripts + + align:start position:0% +going to talk about new types of scripts + + + align:start position:0% +going to talk about new types of scripts +mast taproot and graft route and all the + + align:start position:0% +mast taproot and graft route and all the + + + align:start position:0% +mast taproot and graft route and all the +sort of interactions between these three + + align:start position:0% +sort of interactions between these three + + + align:start position:0% +sort of interactions between these three +things I will define these of course + + align:start position:0% +things I will define these of course + + + align:start position:0% +things I will define these of course +okay so so far we've talked about + + align:start position:0% +okay so so far we've talked about + + + align:start position:0% +okay so so far we've talked about +scripts and you've got op codes you've + + align:start position:0% +scripts and you've got op codes you've + + + align:start position:0% +scripts and you've got op codes you've +got a stack I think with the homework + + align:start position:0% +got a stack I think with the homework + + + align:start position:0% +got a stack I think with the homework +people sort of got the idea of okay I + + align:start position:0% +people sort of got the idea of okay I + + + align:start position:0% +people sort of got the idea of okay I +can do off return I can do op check sig + + align:start position:0% +can do off return I can do op check sig + + + align:start position:0% +can do off return I can do op check sig +you know and the basic idea of how it + + align:start position:0% +you know and the basic idea of how it + + + align:start position:0% +you know and the basic idea of how it +works so right now in Bitcoin it's + + align:start position:0% +works so right now in Bitcoin it's + + + align:start position:0% +works so right now in Bitcoin it's +mostly pay to pub key hash so most of + + align:start position:0% +mostly pay to pub key hash so most of + + + align:start position:0% +mostly pay to pub key hash so most of +the scripts that you'll see most of the + + align:start position:0% +the scripts that you'll see most of the + + + align:start position:0% +the scripts that you'll see most of the +output scripts and then in an output + + align:start position:0% +output scripts and then in an output + + + align:start position:0% +output scripts and then in an output +look like this right op dupe up flash + + align:start position:0% +look like this right op dupe up flash + + + align:start position:0% +look like this right op dupe up flash +160 some pub key hash people verify up + + align:start position:0% +160 some pub key hash people verify up + + + align:start position:0% +160 some pub key hash people verify up +check sake and then when you want to + + align:start position:0% +check sake and then when you want to + + + align:start position:0% +check sake and then when you want to +execute this script you put a pub key + + align:start position:0% +execute this script you put a pub key + + + align:start position:0% +execute this script you put a pub key +and a signature as your input it + + align:start position:0% +and a signature as your input it + + + align:start position:0% +and a signature as your input it +duplicates the pub key hashes it pushes + + align:start position:0% +duplicates the pub key hashes it pushes + + + align:start position:0% +duplicates the pub key hashes it pushes +this hash on to it checks that those two + + align:start position:0% +this hash on to it checks that those two + + + align:start position:0% +this hash on to it checks that those two +things are equal and this also removes + + align:start position:0% +things are equal and this also removes + + + align:start position:0% +things are equal and this also removes +those two things leaving only the + + align:start position:0% +those two things leaving only the + + + align:start position:0% +those two things leaving only the +signature and then checks the signature + + align:start position:0% +signature and then checks the signature + + + align:start position:0% +signature and then checks the signature +so if they're not equal if you try to + + align:start position:0% +so if they're not equal if you try to + + + align:start position:0% +so if they're not equal if you try to +sign with a different pub key than the + + align:start position:0% +sign with a different pub key than the + + + align:start position:0% +sign with a different pub key than the +one that is committed to in this bump + + align:start position:0% +one that is committed to in this bump + + + align:start position:0% +one that is committed to in this bump +key it'll fail at this point and if you + + align:start position:0% +key it'll fail at this point and if you + + + align:start position:0% +key it'll fail at this point and if you +put the right pump key but the wrong + + align:start position:0% +put the right pump key but the wrong + + + align:start position:0% +put the right pump key but the wrong +signature it'll fail at this point right + + align:start position:0% +signature it'll fail at this point right + + + align:start position:0% +signature it'll fail at this point right +so the well it'll fail the check sig + + align:start position:0% +so the well it'll fail the check sig + + + align:start position:0% +so the well it'll fail the check sig +will fail put a zero on the stack and + + align:start position:0% +will fail put a zero on the stack and + + + align:start position:0% +will fail put a zero on the stack and +then the stack will have a zero on it + + align:start position:0% +then the stack will have a zero on it + + + align:start position:0% +then the stack will have a zero on it +and that'll fail verify means + + align:start position:0% +and that'll fail verify means + + + align:start position:0% +and that'll fail verify means +immediately fail if these things are not + + align:start position:0% +immediately fail if these things are not + + + align:start position:0% +immediately fail if these things are not +equal okay and then in seg what we sort + + align:start position:0% +equal okay and then in seg what we sort + + + align:start position:0% +equal okay and then in seg what we sort +of a template in it so really this + + align:start position:0% +of a template in it so really this + + + align:start position:0% +of a template in it so really this +entire script became op 0 pub key ash + + align:start position:0% +entire script became op 0 pub key ash + + + align:start position:0% +entire script became op 0 pub key ash +which is confusing + + align:start position:0% +which is confusing + + + align:start position:0% +which is confusing +if you don't know what that means wait + + align:start position:0% +if you don't know what that means wait + + + align:start position:0% +if you don't know what that means wait +op 0 means just put a 0 on the stack and + + align:start position:0% +op 0 means just put a 0 on the stack and + + + align:start position:0% +op 0 means just put a 0 on the stack and +then put a pub key hash on the stack and + + align:start position:0% +then put a pub key hash on the stack and + + + align:start position:0% +then put a pub key hash on the stack and +and + + align:start position:0% +and + + + align:start position:0% +and +one can spend this but the idea in + + align:start position:0% +one can spend this but the idea in + + + align:start position:0% +one can spend this but the idea in +segments is yes software that is not + + align:start position:0% +segments is yes software that is not + + + align:start position:0% +segments is yes software that is not +aware of segue will see this as + + align:start position:0% +aware of segue will see this as + + + align:start position:0% +aware of segue will see this as +spendable by anyone without a signature + + align:start position:0% +spendable by anyone without a signature + + + align:start position:0% +spendable by anyone without a signature +software that is aware of segue knows + + align:start position:0% +software that is aware of segue knows + + + align:start position:0% +software that is aware of segue knows +that these two things are the same so + + align:start position:0% +that these two things are the same so + + + align:start position:0% +that these two things are the same so +essentially if you see this turn it into + + align:start position:0% +essentially if you see this turn it into + + + align:start position:0% +essentially if you see this turn it into +this right + + align:start position:0% +this right + + + align:start position:0% +this right +take the pub key hash and fill in these + + align:start position:0% +take the pub key hash and fill in these + + + align:start position:0% +take the pub key hash and fill in these +op codes and that's actually what the + + align:start position:0% +op codes and that's actually what the + + + align:start position:0% +op codes and that's actually what the +code does for the script interpreter + + align:start position:0% +code does for the script interpreter + + + align:start position:0% +code does for the script interpreter +it'll say oh it matches this template + + align:start position:0% +it'll say oh it matches this template + + + align:start position:0% +it'll say oh it matches this template +it's op 0 and a 20-byte piece of data + + align:start position:0% +it's op 0 and a 20-byte piece of data + + + align:start position:0% +it's op 0 and a 20-byte piece of data +turn it into this and then execute it so + + align:start position:0% +turn it into this and then execute it so + + + align:start position:0% +turn it into this and then execute it so +in this way segue it saves 3 bytes right + + align:start position:0% +in this way segue it saves 3 bytes right + + + align:start position:0% +in this way segue it saves 3 bytes right +because now you have one byte there + + align:start position:0% +because now you have one byte there + + + align:start position:0% +because now you have one byte there +instead of one two three four you lose a + + align:start position:0% +instead of one two three four you lose a + + + align:start position:0% +instead of one two three four you lose a +couple more bites elsewhere and sangwich + + align:start position:0% +couple more bites elsewhere and sangwich + + + align:start position:0% +couple more bites elsewhere and sangwich +so it actually tends to lose it a couple + + align:start position:0% +so it actually tends to lose it a couple + + + align:start position:0% +so it actually tends to lose it a couple +bites but whatever okay so this this + + align:start position:0% +bites but whatever okay so this this + + + align:start position:0% +bites but whatever okay so this this +works this makes sense any questions + + align:start position:0% +works this makes sense any questions + + + align:start position:0% +works this makes sense any questions +about beta punky hash works okay okay + + align:start position:0% +about beta punky hash works okay okay + + + align:start position:0% +about beta punky hash works okay okay +and there's also pay to script hash this + + align:start position:0% +and there's also pay to script hash this + + + align:start position:0% +and there's also pay to script hash this +is the other thing you'll see quite a + + align:start position:0% +is the other thing you'll see quite a + + + align:start position:0% +is the other thing you'll see quite a +bit of in Bitcoin today I don't know + + align:start position:0% +bit of in Bitcoin today I don't know + + + align:start position:0% +bit of in Bitcoin today I don't know +what the ratios are 80% paid a pumpkin + + align:start position:0% +what the ratios are 80% paid a pumpkin + + + align:start position:0% +what the ratios are 80% paid a pumpkin +has 20% of beta script - something like + + align:start position:0% +has 20% of beta script - something like + + + align:start position:0% +has 20% of beta script - something like +that + + align:start position:0% +that + + + align:start position:0% +that +so minority but significant and for paid + + align:start position:0% +so minority but significant and for paid + + + align:start position:0% +so minority but significant and for paid +a script ash it looks like this also + + align:start position:0% +a script ash it looks like this also + + + align:start position:0% +a script ash it looks like this also +sort of template right up hash 160 a + + align:start position:0% +sort of template right up hash 160 a + + + align:start position:0% +sort of template right up hash 160 a +script hash top equal that's it + + align:start position:0% +script hash top equal that's it + + + align:start position:0% +script hash top equal that's it +this also seems like wait all I have to + + align:start position:0% +this also seems like wait all I have to + + + align:start position:0% +this also seems like wait all I have to +do is provide a pre image of this and + + align:start position:0% +do is provide a pre image of this and + + + align:start position:0% +do is provide a pre image of this and +then I'll be able to spend the coins but + + align:start position:0% +then I'll be able to spend the coins but + + + align:start position:0% +then I'll be able to spend the coins but +the script interpreter knows no actually + + align:start position:0% +the script interpreter knows no actually + + + align:start position:0% +the script interpreter knows no actually +what this means if you see this template + + align:start position:0% +what this means if you see this template + + + align:start position:0% +what this means if you see this template +if you see this format verify that this + + align:start position:0% +if you see this format verify that this + + + align:start position:0% +if you see this format verify that this +is equal and then execute whatever the + + align:start position:0% +is equal and then execute whatever the + + + align:start position:0% +is equal and then execute whatever the +pre image was as a script so actually + + align:start position:0% +pre image was as a script so actually + + + align:start position:0% +pre image was as a script so actually +the first time I started programming + + align:start position:0% +the first time I started programming + + + align:start position:0% +the first time I started programming +Bitcoin stuff I did not know about paid + + align:start position:0% +Bitcoin stuff I did not know about paid + + + align:start position:0% +Bitcoin stuff I did not know about paid +a script hash and I was just trying to + + align:start position:0% +a script hash and I was just trying to + + + align:start position:0% +a script hash and I was just trying to +make my own transactions and I used this + + align:start position:0% +make my own transactions and I used this + + + align:start position:0% +make my own transactions and I used this +I just said well I want to see that I + + align:start position:0% +I just said well I want to see that I + + + align:start position:0% +I just said well I want to see that I +can you know get the script to execute + + align:start position:0% +can you know get the script to execute + + + align:start position:0% +can you know get the script to execute +right I'll just take a random number + + align:start position:0% +right I'll just take a random number + + + align:start position:0% +right I'll just take a random number +hash it put it into this thing and try + + align:start position:0% +hash it put it into this thing and try + + + align:start position:0% +hash it put it into this thing and try +to spend it and it never worked and I + + align:start position:0% +to spend it and it never worked and I + + + align:start position:0% +to spend it and it never worked and I +didn't know why and then a few days + + align:start position:0% +didn't know why and then a few days + + + align:start position:0% +didn't know why and then a few days +later I read about pay to script and I + + align:start position:0% +later I read about pay to script and I + + + align:start position:0% +later I read about pay to script and I +was like oh no wait it wasn't days later + + align:start position:0% +was like oh no wait it wasn't days later + + + align:start position:0% +was like oh no wait it wasn't days later +I just put an OP I put an op no op op + + align:start position:0% +I just put an OP I put an op no op op + + + align:start position:0% +I just put an OP I put an op no op op +one-sixty script pêche up equal and then + + align:start position:0% +one-sixty script pêche up equal and then + + + align:start position:0% +one-sixty script pêche up equal and then +it worked and I was like okay I don't + + align:start position:0% +it worked and I was like okay I don't + + + align:start position:0% +it worked and I was like okay I don't +know how Bitcoin works this doesn't make + + align:start position:0% +know how Bitcoin works this doesn't make + + + align:start position:0% +know how Bitcoin works this doesn't make +any sense I put a no op and then it + + align:start position:0% +any sense I put a no op and then it + + + align:start position:0% +any sense I put a no op and then it +starts working and then a few days later + + align:start position:0% +starts working and then a few days later + + + align:start position:0% +starts working and then a few days later +I read about paid a script cash and it + + align:start position:0% +I read about paid a script cash and it + + + align:start position:0% +I read about paid a script cash and it +was oh this actually has a special + + align:start position:0% +was oh this actually has a special + + + align:start position:0% +was oh this actually has a special +meaning this is a template where if you + + align:start position:0% +meaning this is a template where if you + + + align:start position:0% +meaning this is a template where if you +have - 60 a bunch of data and not equal + + align:start position:0% +have - 60 a bunch of data and not equal + + + align:start position:0% +have - 60 a bunch of data and not equal +then it interprets the preimage as a + + align:start position:0% +then it interprets the preimage as a + + + align:start position:0% +then it interprets the preimage as a +script does it have to be 20 bytes + + align:start position:0% +script does it have to be 20 bytes + + + align:start position:0% +script does it have to be 20 bytes +probably yeah I don't know there's + + align:start position:0% +probably yeah I don't know there's + + + align:start position:0% +probably yeah I don't know there's +actually a vulnerability here that the + + align:start position:0% +actually a vulnerability here that the + + + align:start position:0% +actually a vulnerability here that the +how pay to script hash got introduced is + + align:start position:0% +how pay to script hash got introduced is + + + align:start position:0% +how pay to script hash got introduced is +sort of an interesting debate there was + + align:start position:0% +sort of an interesting debate there was + + + align:start position:0% +sort of an interesting debate there was +like op eval paid a script hash a bunch + + align:start position:0% +like op eval paid a script hash a bunch + + + align:start position:0% +like op eval paid a script hash a bunch +of argument about it and this was in + + align:start position:0% +of argument about it and this was in + + + align:start position:0% +of argument about it and this was in +2012 I think or 11 or 12 and it it was + + align:start position:0% +2012 I think or 11 or 12 and it it was + + + align:start position:0% +2012 I think or 11 or 12 and it it was +sort of contentious and people argue + + align:start position:0% +sort of contentious and people argue + + + align:start position:0% +sort of contentious and people argue +about it and and in retrospect this is + + align:start position:0% +about it and and in retrospect this is + + + align:start position:0% +about it and and in retrospect this is +actually insecure because you're using + + align:start position:0% +actually insecure because you're using + + + align:start position:0% +actually insecure because you're using +hop hash 160 which is 160 bytes hash + + align:start position:0% +hop hash 160 which is 160 bytes hash + + + align:start position:0% +hop hash 160 which is 160 bytes hash +function it's basically sha 256 followed + + align:start position:0% +function it's basically sha 256 followed + + + align:start position:0% +function it's basically sha 256 followed +by ripe MD 160 this is not big enough + + align:start position:0% +by ripe MD 160 this is not big enough + + + align:start position:0% +by ripe MD 160 this is not big enough +right you have you're committing to a + + align:start position:0% +right you have you're committing to a + + + align:start position:0% +right you have you're committing to a +script cache which is 20 bytes + + align:start position:0% +script cache which is 20 bytes + + + align:start position:0% +script cache which is 20 bytes +however cool so normally you're like + + align:start position:0% +however cool so normally you're like + + + align:start position:0% +however cool so normally you're like +yeah whatever 160 bits is plenty you can + + align:start position:0% +yeah whatever 160 bits is plenty you can + + + align:start position:0% +yeah whatever 160 bits is plenty you can +have collision attacks where if you're + + align:start position:0% +have collision attacks where if you're + + + align:start position:0% +have collision attacks where if you're +doing multi-sig with someone else they + + align:start position:0% +doing multi-sig with someone else they + + + align:start position:0% +doing multi-sig with someone else they +may be able to calculate different pub + + align:start position:0% +may be able to calculate different pub + + + align:start position:0% +may be able to calculate different pub +keys so that your pump key you know they + + align:start position:0% +keys so that your pump key you know they + + + align:start position:0% +keys so that your pump key you know they +have a collision where two different 20 + + align:start position:0% +have a collision where two different 20 + + + align:start position:0% +have a collision where two different 20 +bite scripts hash to the same thing + + align:start position:0% +bite scripts hash to the same thing + + + align:start position:0% +bite scripts hash to the same thing +there's sorry two different scripts hash + + align:start position:0% +there's sorry two different scripts hash + + + align:start position:0% +there's sorry two different scripts hash +to the same 20 bytes this is possible + + align:start position:0% +to the same 20 bytes this is possible + + + align:start position:0% +to the same 20 bytes this is possible +because that's only two to the 80 work + + align:start position:0% +because that's only two to the 80 work + + + align:start position:0% +because that's only two to the 80 work +which is still a lot and used to be + + align:start position:0% +which is still a lot and used to be + + + align:start position:0% +which is still a lot and used to be +considered like no one can do it to the + + align:start position:0% +considered like no one can do it to the + + + align:start position:0% +considered like no one can do it to the +80 is like beyond any human endeavor but + + align:start position:0% +80 is like beyond any human endeavor but + + + align:start position:0% +80 is like beyond any human endeavor but +Bitcoin does - to the 80 work every day + + align:start position:0% +Bitcoin does - to the 80 work every day + + + align:start position:0% +Bitcoin does - to the 80 work every day +hour + + align:start position:0% +hour + + + align:start position:0% +hour +I don't know something fairly reasonable + + align:start position:0% +I don't know something fairly reasonable + + + align:start position:0% +I don't know something fairly reasonable +so so now it's like wait - of the 80 is + + align:start position:0% +so so now it's like wait - of the 80 is + + + align:start position:0% +so so now it's like wait - of the 80 is +not enough we need you reach for the + + align:start position:0% +not enough we need you reach for the + + + align:start position:0% +not enough we need you reach for the +same security as Bitcoin which is + + align:start position:0% +same security as Bitcoin which is + + + align:start position:0% +same security as Bitcoin which is +generally a two to the 128 security + + align:start position:0% +generally a two to the 128 security + + + align:start position:0% +generally a two to the 128 security +parameter we would need this to be 256 + + align:start position:0% +parameter we would need this to be 256 + + + align:start position:0% +parameter we would need this to be 256 +bits instead of 160 so when they + + align:start position:0% +bits instead of 160 so when they + + + align:start position:0% +bits instead of 160 so when they +upgraded the segment paid a witness + + align:start position:0% +upgraded the segment paid a witness + + + align:start position:0% +upgraded the segment paid a witness +script hash + + align:start position:0% +script hash + + + align:start position:0% +script hash +this has to be 32 bytes to eliminate any + + align:start position:0% +this has to be 32 bytes to eliminate any + + + align:start position:0% +this has to be 32 bytes to eliminate any +of those collisions of ulnar abilities + + align:start position:0% +of those collisions of ulnar abilities + + + align:start position:0% +of those collisions of ulnar abilities +so yeah so that's what distinguishes it + + align:start position:0% +so yeah so that's what distinguishes it + + + align:start position:0% +so yeah so that's what distinguishes it +so they look the same right + + align:start position:0% +so they look the same right + + + align:start position:0% +so they look the same right +it's just op 0 piece of data obsolete + + align:start position:0% +it's just op 0 piece of data obsolete + + + align:start position:0% +it's just op 0 piece of data obsolete +but they do completely different things + + align:start position:0% +but they do completely different things + + + align:start position:0% +but they do completely different things +based on how long the state is okay so + + align:start position:0% +based on how long the state is okay so + + + align:start position:0% +based on how long the state is okay so +that's pay descript hash any questions + + align:start position:0% +that's pay descript hash any questions + + + align:start position:0% +that's pay descript hash any questions +about the basic construction good ok I + + align:start position:0% +about the basic construction good ok I + + + align:start position:0% +about the basic construction good ok I +want to these free keys must sign in + + align:start position:0% +want to these free keys must sign in + + + align:start position:0% +want to these free keys must sign in +order to spend the coins so I say up to + + align:start position:0% +order to spend the coins so I say up to + + + align:start position:0% +order to spend the coins so I say up to +push three public keys onto the you know + + align:start position:0% +push three public keys onto the you know + + + align:start position:0% +push three public keys onto the you know +three public keys up three up check + + align:start position:0% +three public keys up three up check + + + align:start position:0% +three public keys up three up check +models you say so the idea is two of + + align:start position:0% +models you say so the idea is two of + + + align:start position:0% +models you say so the idea is two of +these three must sign so you can put off + + align:start position:0% +these three must sign so you can put off + + + align:start position:0% +these three must sign so you can put off +lon + + align:start position:0% +lon + + + align:start position:0% +lon +this OP three you can put up three this + + align:start position:0% +this OP three you can put up three this + + + align:start position:0% +this OP three you can put up three this +up three if you put up four three keys + + align:start position:0% +up three if you put up four three keys + + + align:start position:0% +up three if you put up four three keys +and then up three it probably will never + + align:start position:0% +and then up three it probably will never + + + align:start position:0% +and then up three it probably will never +be spendable and just never work I'm + + align:start position:0% +be spendable and just never work I'm + + + align:start position:0% +be spendable and just never work I'm +pretty sure you have to put the + + align:start position:0% +pretty sure you have to put the + + + align:start position:0% +pretty sure you have to put the +signatures in the correct order so when + + align:start position:0% +signatures in the correct order so when + + + align:start position:0% +signatures in the correct order so when +you spend you say op zero sig a 6e and + + align:start position:0% +you spend you say op zero sig a 6e and + + + align:start position:0% +you spend you say op zero sig a 6e and +then it's a see if you put sig see sig a + + align:start position:0% +then it's a see if you put sig see sig a + + + align:start position:0% +then it's a see if you put sig see sig a +it fails right okay this is a fun little + + align:start position:0% +it fails right okay this is a fun little + + + align:start position:0% +it fails right okay this is a fun little +part where you have to put in a zero + + align:start position:0% +part where you have to put in a zero + + + align:start position:0% +part where you have to put in a zero +byte before the signature is when you + + align:start position:0% +byte before the signature is when you + + + align:start position:0% +byte before the signature is when you +want to spend I'm not a hundred percent + + align:start position:0% +want to spend I'm not a hundred percent + + + align:start position:0% +want to spend I'm not a hundred percent +sure how that got in it was the screw up + + align:start position:0% +sure how that got in it was the screw up + + + align:start position:0% +sure how that got in it was the screw up +and we're just we just live with it + + align:start position:0% +and we're just we just live with it + + + align:start position:0% +and we're just we just live with it +forever you don't put the OP 0 it + + align:start position:0% +forever you don't put the OP 0 it + + + align:start position:0% +forever you don't put the OP 0 it +doesn't work and it's somewhat confusing + + align:start position:0% +doesn't work and it's somewhat confusing + + + align:start position:0% +doesn't work and it's somewhat confusing +it wastes the byte which is not a huge + + align:start position:0% +it wastes the byte which is not a huge + + + align:start position:0% +it wastes the byte which is not a huge +deal but it's just like what and they + + align:start position:0% +deal but it's just like what and they + + + align:start position:0% +deal but it's just like what and they +didn't fix that in segue right yeah we + + align:start position:0% +didn't fix that in segue right yeah we + + + align:start position:0% +didn't fix that in segue right yeah we +just stays in there who knows if it'll + + align:start position:0% +just stays in there who knows if it'll + + + align:start position:0% +just stays in there who knows if it'll +ever get out + + align:start position:0% +ever get out + + + align:start position:0% +ever get out +so saying it was an opportunity to fix + + align:start position:0% +so saying it was an opportunity to fix + + + align:start position:0% +so saying it was an opportunity to fix +it but yes + + align:start position:0% + + + + align:start position:0% + +hard work so you put this in and you + + align:start position:0% +hard work so you put this in and you + + + align:start position:0% +hard work so you put this in and you +could say wait + + align:start position:0% +could say wait + + + align:start position:0% +could say wait +that's stupid wait you need a zero in + + align:start position:0% +that's stupid wait you need a zero in + + + align:start position:0% +that's stupid wait you need a zero in +front when you put the signors let's get + + align:start position:0% +front when you put the signors let's get + + + align:start position:0% +front when you put the signors let's get +rid of that so so now the old software + + align:start position:0% +rid of that so so now the old software + + + align:start position:0% +rid of that so so now the old software +says no I need a zero here and then if + + align:start position:0% +says no I need a zero here and then if + + + align:start position:0% +says no I need a zero here and then if +you if you don't put the zero and you + + align:start position:0% +you if you don't put the zero and you + + + align:start position:0% +you if you don't put the zero and you +just put the two signatures I fail this + + align:start position:0% +just put the two signatures I fail this + + + align:start position:0% +just put the two signatures I fail this +script and then it could just be any + + align:start position:0% +script and then it could just be any + + + align:start position:0% +script and then it could just be any +note any data and it was like any data + + align:start position:0% +note any data and it was like any data + + + align:start position:0% +note any data and it was like any data +any data on the stack would get it would + + align:start position:0% +any data on the stack would get it would + + + align:start position:0% +any data on the stack would get it would +get popped off right yeah and then the + + align:start position:0% +get popped off right yeah and then the + + + align:start position:0% +get popped off right yeah and then the +two signatures so if you said let's + + align:start position:0% +two signatures so if you said let's + + + align:start position:0% +two signatures so if you said let's +eliminate that requirement that would + + align:start position:0% +eliminate that requirement that would + + + align:start position:0% +eliminate that requirement that would +actually be a hard fork because it would + + align:start position:0% +actually be a hard fork because it would + + + align:start position:0% +actually be a hard fork because it would +be allowing scripts that were previously + + align:start position:0% +be allowing scripts that were previously + + + align:start position:0% +be allowing scripts that were previously +invalid to now become valid and that's a + + align:start position:0% +invalid to now become valid and that's a + + + align:start position:0% +invalid to now become valid and that's a +huge undertaking that has sort of only + + align:start position:0% +huge undertaking that has sort of only + + + align:start position:0% +huge undertaking that has sort of only +happened once in Bitcoin and that wasn't + + align:start position:0% +happened once in Bitcoin and that wasn't + + + align:start position:0% +happened once in Bitcoin and that wasn't +even planned and so it's just like + + align:start position:0% +even planned and so it's just like + + + align:start position:0% +even planned and so it's just like +whatever leave it they did soft work it + + align:start position:0% +whatever leave it they did soft work it + + + align:start position:0% +whatever leave it they did soft work it +then wait is it software or policy okay + + align:start position:0% +then wait is it software or policy okay + + + align:start position:0% +then wait is it software or policy okay +so they didn't sophomore could say it + + align:start position:0% +so they didn't sophomore could say it + + + align:start position:0% +so they didn't sophomore could say it +needs to be a zero so it could be + + align:start position:0% +needs to be a zero so it could be + + + align:start position:0% +needs to be a zero so it could be +non-standard or it could be an actual + + align:start position:0% +non-standard or it could be an actual + + + align:start position:0% +non-standard or it could be an actual +consensus rule that that has to be a + + align:start position:0% +consensus rule that that has to be a + + + align:start position:0% +consensus rule that that has to be a +zero it used to be anything and now it's + + align:start position:0% +zero it used to be anything and now it's + + + align:start position:0% +zero it used to be anything and now it's +it should be a zero put a zero and then + + align:start position:0% +it should be a zero put a zero and then + + + align:start position:0% +it should be a zero put a zero and then +it'll work + + align:start position:0% +it'll work + + + align:start position:0% +it'll work +but that that remains in segments as + + align:start position:0% +but that that remains in segments as + + + align:start position:0% +but that that remains in segments as +well with multi-sig they could have + + align:start position:0% +well with multi-sig they could have + + + align:start position:0% +well with multi-sig they could have +fixed it they didn't want to touch it it + + align:start position:0% +fixed it they didn't want to touch it it + + + align:start position:0% +fixed it they didn't want to touch it it +was just like whatever let you know when + + align:start position:0% +was just like whatever let you know when + + + align:start position:0% +was just like whatever let you know when +you see a when you see one of these turn + + align:start position:0% +you see a when you see one of these turn + + + align:start position:0% +you see a when you see one of these turn +it into one of these and just do the + + align:start position:0% +it into one of these and just do the + + + align:start position:0% +it into one of these and just do the +exact same thing you used to be doing + + align:start position:0% +exact same thing you used to be doing + + + align:start position:0% +exact same thing you used to be doing +that's a lot simpler and easier okay so + + align:start position:0% +that's a lot simpler and easier okay so + + + align:start position:0% +that's a lot simpler and easier okay so +kind of weird but this works right + + align:start position:0% +kind of weird but this works right + + + align:start position:0% +kind of weird but this works right +people use this a lot especially + + align:start position:0% +people use this a lot especially + + + align:start position:0% +people use this a lot especially +exchanges exchanges almost I very very + + align:start position:0% +exchanges exchanges almost I very very + + + align:start position:0% +exchanges exchanges almost I very very +often use this kind of construction + + align:start position:0% +often use this kind of construction + + + align:start position:0% +often use this kind of construction +because it helps people manage keys if + + align:start position:0% +because it helps people manage keys if + + + align:start position:0% +because it helps people manage keys if +one key gets compromised you don't lose + + align:start position:0% +one key gets compromised you don't lose + + + align:start position:0% +one key gets compromised you don't lose +all your money usually two of three + + align:start position:0% +all your money usually two of three + + + align:start position:0% +all your money usually two of three +sometimes three or four three of three + + align:start position:0% +sometimes three or four three of three + + + align:start position:0% +sometimes three or four three of three +two of to all sorts of constructions + + align:start position:0% +two of to all sorts of constructions + + + align:start position:0% +two of to all sorts of constructions +where this is extremely useful and + + align:start position:0% +where this is extremely useful and + + + align:start position:0% +where this is extremely useful and +actually I'll be talking about more + + align:start position:0% +actually I'll be talking about more + + + align:start position:0% +actually I'll be talking about more +powerful signature aggregation and + + align:start position:0% +powerful signature aggregation and + + + align:start position:0% +powerful signature aggregation and +multi-sig on Wednesday but for now this + + align:start position:0% +multi-sig on Wednesday but for now this + + + align:start position:0% +multi-sig on Wednesday but for now this +is what we use and how can + + align:start position:0% +is what we use and how can + + + align:start position:0% +is what we use and how can +we make this better so one interesting + + align:start position:0% +we make this better so one interesting + + + align:start position:0% +we make this better so one interesting +thing pay to pub key which is not really + + align:start position:0% +thing pay to pub key which is not really + + + align:start position:0% +thing pay to pub key which is not really +used anymore but used to be mused more + + align:start position:0% +used anymore but used to be mused more + + + align:start position:0% +used anymore but used to be mused more +frequently like in the early days like + + align:start position:0% +frequently like in the early days like + + + align:start position:0% +frequently like in the early days like +if you look at transactions in 2009-2010 + + align:start position:0% +if you look at transactions in 2009-2010 + + + align:start position:0% +if you look at transactions in 2009-2010 +this is predominant I think and like all + + align:start position:0% +this is predominant I think and like all + + + align:start position:0% +this is predominant I think and like all +the mining outputs from a long time ago + + align:start position:0% +the mining outputs from a long time ago + + + align:start position:0% +the mining outputs from a long time ago +looked like this and the script the + + align:start position:0% +looked like this and the script the + + + align:start position:0% +looked like this and the script the +output script was just pump key objects + + align:start position:0% +output script was just pump key objects + + + align:start position:0% +output script was just pump key objects +ache which is really simple and then the + + align:start position:0% +ache which is really simple and then the + + + align:start position:0% +ache which is really simple and then the +idea is when you want to spend it you + + align:start position:0% +idea is when you want to spend it you + + + align:start position:0% +idea is when you want to spend it you +just push a signature on to the stack + + align:start position:0% +just push a signature on to the stack + + + align:start position:0% +just push a signature on to the stack +then you have signature pub key op check + + align:start position:0% +then you have signature pub key op check + + + align:start position:0% +then you have signature pub key op check +sig that's it it's really simple and it + + align:start position:0% +sig that's it it's really simple and it + + + align:start position:0% +sig that's it it's really simple and it +actually saves space right your pub key + + align:start position:0% +actually saves space right your pub key + + + align:start position:0% +actually saves space right your pub key +is 33 bytes whereas your pub key hash + + align:start position:0% +is 33 bytes whereas your pub key hash + + + align:start position:0% +is 33 bytes whereas your pub key hash +script the the pub key hash is 20 bytes + + align:start position:0% +script the the pub key hash is 20 bytes + + + align:start position:0% +script the the pub key hash is 20 bytes +so yeah the pub key hash is 12 bytes + + align:start position:0% +so yeah the pub key hash is 12 bytes + + + align:start position:0% +so yeah the pub key hash is 12 bytes +smaller plus the extra op codes makes it + + align:start position:0% +smaller plus the extra op codes makes it + + + align:start position:0% +smaller plus the extra op codes makes it +10 bytes savings for the output script + + align:start position:0% +10 bytes savings for the output script + + + align:start position:0% +10 bytes savings for the output script +right however when you spend with pay to + + align:start position:0% +right however when you spend with pay to + + + align:start position:0% +right however when you spend with pay to +pump key hash you need to put the pump + + align:start position:0% +pump key hash you need to put the pump + + + align:start position:0% +pump key hash you need to put the pump +key itself and the signature so you're + + align:start position:0% +key itself and the signature so you're + + + align:start position:0% +key itself and the signature so you're +putting that you're putting the pub key + + align:start position:0% +putting that you're putting the pub key + + + align:start position:0% +putting that you're putting the pub key +into the network either way eventually + + align:start position:0% +into the network either way eventually + + + align:start position:0% +into the network either way eventually +so this is actually overall more space + + align:start position:0% +so this is actually overall more space + + + align:start position:0% +so this is actually overall more space +efficient in that you're saving 23 bytes + + align:start position:0% +efficient in that you're saving 23 bytes + + + align:start position:0% +efficient in that you're saving 23 bytes +over the life cycle of it right when you + + align:start position:0% +over the life cycle of it right when you + + + align:start position:0% +over the life cycle of it right when you +the output is a little bit bigger but + + align:start position:0% +the output is a little bit bigger but + + + align:start position:0% +the output is a little bit bigger but +the input is significantly smaller so + + align:start position:0% +the input is significantly smaller so + + + align:start position:0% +the input is significantly smaller so +you end up saving why why do we always + + align:start position:0% +you end up saving why why do we always + + + align:start position:0% +you end up saving why why do we always +use pub key hashes instead of pump keys + + align:start position:0% +use pub key hashes instead of pump keys + + + align:start position:0% +use pub key hashes instead of pump keys +then does anyone there's a lot of + + align:start position:0% +then does anyone there's a lot of + + + align:start position:0% +then does anyone there's a lot of +different opinions on it and there's no + + align:start position:0% +different opinions on it and there's no + + + align:start position:0% +different opinions on it and there's no +you know it's a Bitcoin there's no like + + align:start position:0% +you know it's a Bitcoin there's no like + + + align:start position:0% +you know it's a Bitcoin there's no like +answer people have different ideas of + + align:start position:0% +answer people have different ideas of + + + align:start position:0% +answer people have different ideas of +why these are better any it is + + align:start position:0% + + + + align:start position:0% + +yeah that's a that's a really probably + + align:start position:0% +yeah that's a that's a really probably + + + align:start position:0% +yeah that's a that's a really probably +the predominant one and that's gonna be + + align:start position:0% +the predominant one and that's gonna be + + + align:start position:0% +the predominant one and that's gonna be +a tricky one to try to convince people + + align:start position:0% +a tricky one to try to convince people + + + align:start position:0% +a tricky one to try to convince people +is not the case because I'll get to that + + align:start position:0% +is not the case because I'll get to that + + + align:start position:0% +is not the case because I'll get to that +but we people started arguing about like + + align:start position:0% +but we people started arguing about like + + + align:start position:0% +but we people started arguing about like +funky Asha won when when someone posted + + align:start position:0% +funky Asha won when when someone posted + + + align:start position:0% +funky Asha won when when someone posted +about grassroot everyone the discussion + + align:start position:0% +about grassroot everyone the discussion + + + align:start position:0% +about grassroot everyone the discussion +devolved into a wait I don't want my pub + + align:start position:0% +devolved into a wait I don't want my pub + + + align:start position:0% +devolved into a wait I don't want my pub +key on the network and and there's some + + align:start position:0% +key on the network and and there's some + + + align:start position:0% +key on the network and and there's some +arguments why you'd want a pub key hash + + align:start position:0% +arguments why you'd want a pub key hash + + + align:start position:0% +arguments why you'd want a pub key hash +and it's more secure but there's a lot + + align:start position:0% +and it's more secure but there's a lot + + + align:start position:0% +and it's more secure but there's a lot +of arguments that it doesn't actually + + align:start position:0% +of arguments that it doesn't actually + + + align:start position:0% +of arguments that it doesn't actually +provide any extra security so that's a + + align:start position:0% +provide any extra security so that's a + + + align:start position:0% +provide any extra security so that's a +tricky one but that is one that is + + align:start position:0% +tricky one but that is one that is + + + align:start position:0% +tricky one but that is one that is +probably a big one people like other + + align:start position:0% +probably a big one people like other + + + align:start position:0% +probably a big one people like other +ideas why do use punky hashes instead of + + align:start position:0% +ideas why do use punky hashes instead of + + + align:start position:0% +ideas why do use punky hashes instead of +pub keys themselves okay so sighs you + + align:start position:0% +pub keys themselves okay so sighs you + + + align:start position:0% +pub keys themselves okay so sighs you +want the outputs to be small also I'm + + align:start position:0% +want the outputs to be small also I'm + + + align:start position:0% +want the outputs to be small also I'm +pretty sure when Satoshi wrote all this + + align:start position:0% +pretty sure when Satoshi wrote all this + + + align:start position:0% +pretty sure when Satoshi wrote all this +he did not know about compressed public + + align:start position:0% +he did not know about compressed public + + + align:start position:0% +he did not know about compressed public +keys because that stuff was not in there + + align:start position:0% +keys because that stuff was not in there + + + align:start position:0% +keys because that stuff was not in there +for a while so I think I think I + + align:start position:0% +for a while so I think I think I + + + align:start position:0% +for a while so I think I think I +mentioned this before right did I + + align:start position:0% +mentioned this before right did I + + + align:start position:0% +mentioned this before right did I +mention compressed versus uncompressed + + align:start position:0% +mention compressed versus uncompressed + + + align:start position:0% +mention compressed versus uncompressed +web keys yeah probably + + align:start position:0% +web keys yeah probably + + + align:start position:0% +web keys yeah probably +okay so review the idea is you've got + + align:start position:0% +okay so review the idea is you've got + + + align:start position:0% +okay so review the idea is you've got +this whole curve kind of deal kind of + + align:start position:0% +this whole curve kind of deal kind of + + + align:start position:0% +this whole curve kind of deal kind of +thing and your your public key is a + + align:start position:0% +thing and your your public key is a + + + align:start position:0% +thing and your your public key is a +point on the curve you need an x and + + align:start position:0% +point on the curve you need an x and + + + align:start position:0% +point on the curve you need an x and +y-coordinate to represent the point + + align:start position:0% +y-coordinate to represent the point + + + align:start position:0% +y-coordinate to represent the point +however because it's symmetric you can + + align:start position:0% +however because it's symmetric you can + + + align:start position:0% +however because it's symmetric you can +just say well I'll tell you the x + + align:start position:0% +just say well I'll tell you the x + + + align:start position:0% +just say well I'll tell you the x +coordinate you know x equals seven I'm + + align:start position:0% +coordinate you know x equals seven I'm + + + align:start position:0% +coordinate you know x equals seven I'm +not going to tell you the y coordinate + + align:start position:0% +not going to tell you the y coordinate + + + align:start position:0% +not going to tell you the y coordinate +I'll just say y equals plus so Y you + + align:start position:0% +I'll just say y equals plus so Y you + + + align:start position:0% +I'll just say y equals plus so Y you +know go up or go down that way I can do + + align:start position:0% +know go up or go down that way I can do + + + align:start position:0% +know go up or go down that way I can do +32 bytes for this and one bit for that + + align:start position:0% +32 bytes for this and one bit for that + + + align:start position:0% +32 bytes for this and one bit for that +had the cost of a little bit of extra + + align:start position:0% +had the cost of a little bit of extra + + + align:start position:0% +had the cost of a little bit of extra +computation because then when I when I + + align:start position:0% +computation because then when I when I + + + align:start position:0% +computation because then when I when I +see you know so I could say maybe Y is + + align:start position:0% +see you know so I could say maybe Y is + + + align:start position:0% +see you know so I could say maybe Y is +actually five or something so if I say x + + align:start position:0% +actually five or something so if I say x + + + align:start position:0% +actually five or something so if I say x +equals seven y equals five that's quick + + align:start position:0% +equals seven y equals five that's quick + + + align:start position:0% +equals seven y equals five that's quick +but it takes more space if I say x + + align:start position:0% +but it takes more space if I say x + + + align:start position:0% +but it takes more space if I say x +equals seven y equals plus I not have to + + align:start position:0% +equals seven y equals plus I not have to + + + align:start position:0% +equals seven y equals plus I not have to +compute what Y is when I see this which + + align:start position:0% +compute what Y is when I see this which + + + align:start position:0% +compute what Y is when I see this which +is pretty quick + + align:start position:0% +is pretty quick + + + align:start position:0% +is pretty quick +what takes some time but it's good + + align:start position:0% +what takes some time but it's good + + + align:start position:0% +what takes some time but it's good +trade-off anyway I don't think Satoshi + + align:start position:0% +trade-off anyway I don't think Satoshi + + + align:start position:0% +trade-off anyway I don't think Satoshi +knew about this idea + + align:start position:0% +knew about this idea + + + align:start position:0% +knew about this idea +or it may be thought of it never put it + + align:start position:0% +or it may be thought of it never put it + + + align:start position:0% +or it may be thought of it never put it +in so the public keys were actually 65 + + align:start position:0% +in so the public keys were actually 65 + + + align:start position:0% +in so the public keys were actually 65 +flights you want to keep the outputs + + align:start position:0% +flights you want to keep the outputs + + + align:start position:0% +flights you want to keep the outputs +small because they're in the UT Exocet + + align:start position:0% +small because they're in the UT Exocet + + + align:start position:0% +small because they're in the UT Exocet +they're in the database and you need to + + align:start position:0% +they're in the database and you need to + + + align:start position:0% +they're in the database and you need to +be alone through this and read it + + align:start position:0% +be alone through this and read it + + + align:start position:0% +be alone through this and read it +randomly like you don't know when it's + + align:start position:0% +randomly like you don't know when it's + + + align:start position:0% +randomly like you don't know when it's +gonna get spent so you don't know what + + align:start position:0% +gonna get spent so you don't know what + + + align:start position:0% +gonna get spent so you don't know what +transaction is going to query this so + + align:start position:0% +transaction is going to query this so + + + align:start position:0% +transaction is going to query this so +this has to go in like an actual + + align:start position:0% +this has to go in like an actual + + + align:start position:0% +this has to go in like an actual +database key value store kind of thing + + align:start position:0% +database key value store kind of thing + + + align:start position:0% +database key value store kind of thing +the signatures are don't have to be in + + align:start position:0% +the signatures are don't have to be in + + + align:start position:0% +the signatures are don't have to be in +any database they're just in these old + + align:start position:0% +any database they're just in these old + + + align:start position:0% +any database they're just in these old +blocks and you read from them linearly + + align:start position:0% +blocks and you read from them linearly + + + align:start position:0% +blocks and you read from them linearly +you basically read for the whole block + + align:start position:0% +you basically read for the whole block + + + align:start position:0% +you basically read for the whole block +at a time and high latency is fine + + align:start position:0% +at a time and high latency is fine + + + align:start position:0% +at a time and high latency is fine +there's never any timing critical reads + + align:start position:0% +there's never any timing critical reads + + + align:start position:0% +there's never any timing critical reads +for this so basically you can just you + + align:start position:0% +for this so basically you can just you + + + align:start position:0% +for this so basically you can just you +could store the blocks as just files on + + align:start position:0% +could store the blocks as just files on + + + align:start position:0% +could store the blocks as just files on +your hard drive you know block block 1 + + align:start position:0% +your hard drive you know block block 1 + + + align:start position:0% +your hard drive you know block block 1 +dot dat or whatever block 2 dot that and + + align:start position:0% +dot dat or whatever block 2 dot that and + + + align:start position:0% +dot dat or whatever block 2 dot that and +have 500,000 files because you basically + + align:start position:0% +have 500,000 files because you basically + + + align:start position:0% +have 500,000 files because you basically +always read them a block at a time + + align:start position:0% +always read them a block at a time + + + align:start position:0% +always read them a block at a time +and you and you only have to read them + + align:start position:0% +and you and you only have to read them + + + align:start position:0% +and you and you only have to read them +when peep other people are doing IBD + + align:start position:0% +when peep other people are doing IBD + + + align:start position:0% +when peep other people are doing IBD +initial block download and you're + + align:start position:0% +initial block download and you're + + + align:start position:0% +initial block download and you're +serving them to them so you can prune + + align:start position:0% +serving them to them so you can prune + + + align:start position:0% +serving them to them so you can prune +these if you run a Bitcoin core with + + align:start position:0% +these if you run a Bitcoin core with + + + align:start position:0% +these if you run a Bitcoin core with +pruning anyway so that the main set idea + + align:start position:0% +pruning anyway so that the main set idea + + + align:start position:0% +pruning anyway so that the main set idea +is ok even if it overall increases the + + align:start position:0% +is ok even if it overall increases the + + + align:start position:0% +is ok even if it overall increases the +size of transactions it does reduce the + + align:start position:0% +size of transactions it does reduce the + + + align:start position:0% +size of transactions it does reduce the +size of the outputs which is the thing + + align:start position:0% +size of the outputs which is the thing + + + align:start position:0% +size of the outputs which is the thing +we really want to minimize for keeping + + align:start position:0% +we really want to minimize for keeping + + + align:start position:0% +we really want to minimize for keeping +the speed up ok questions about that + + align:start position:0% +the speed up ok questions about that + + + align:start position:0% +the speed up ok questions about that +cool ok so similarly same thing with + + align:start position:0% +cool ok so similarly same thing with + + + align:start position:0% +cool ok so similarly same thing with +beta punky hash and you know versus pay + + align:start position:0% +beta punky hash and you know versus pay + + + align:start position:0% +beta punky hash and you know versus pay +to punky instead of paid a script hash + + align:start position:0% +to punky instead of paid a script hash + + + align:start position:0% +to punky instead of paid a script hash +you could put the whole script in an + + align:start position:0% +you could put the whole script in an + + + align:start position:0% +you could put the whole script in an +output like a multi-city you could just + + align:start position:0% +output like a multi-city you could just + + + align:start position:0% +output like a multi-city you could just +have all three of your keys in your + + align:start position:0% +have all three of your keys in your + + + align:start position:0% +have all three of your keys in your +output script and that would save space + + align:start position:0% +output script and that would save space + + + align:start position:0% +output script and that would save space +over all your output is 20 bytes and + + align:start position:0% +over all your output is 20 bytes and + + + align:start position:0% +over all your output is 20 bytes and +then you reveal your whole hundred byte + + align:start position:0% +then you reveal your whole hundred byte + + + align:start position:0% +then you reveal your whole hundred byte +script so you save those 20 bytes same + + align:start position:0% +script so you save those 20 bytes same + + + align:start position:0% +script so you save those 20 bytes same +same amount but proportionally less time + + align:start position:0% +same amount but proportionally less time + + + align:start position:0% +same amount but proportionally less time +but it's you know it is some space + + align:start position:0% +but it's you know it is some space + + + align:start position:0% +but it's you know it is some space +savings overall but it's better to keep + + align:start position:0% +savings overall but it's better to keep + + + align:start position:0% +savings overall but it's better to keep +the output spot size small for you is if + + align:start position:0% +the output spot size small for you is if + + + align:start position:0% +the output spot size small for you is if +you do this does it actually work so it + + align:start position:0% +you do this does it actually work so it + + + align:start position:0% +you do this does it actually work so it +might not properly + + align:start position:0% +might not properly + + + align:start position:0% +might not properly +yeah so so it don't I wouldn't recommend + + align:start position:0% +yeah so so it don't I wouldn't recommend + + + align:start position:0% +yeah so so it don't I wouldn't recommend +this it probably will not really work + + align:start position:0% +this it probably will not really work + + + align:start position:0% +this it probably will not really work +maybe eventually it'll get confirmed if + + align:start position:0% +maybe eventually it'll get confirmed if + + + align:start position:0% +maybe eventually it'll get confirmed if +you find people to confirm it for you + + align:start position:0% +you find people to confirm it for you + + + align:start position:0% +you find people to confirm it for you +but most nodes will ignore these kinds + + align:start position:0% +but most nodes will ignore these kinds + + + align:start position:0% +but most nodes will ignore these kinds +of things okay so the question for today + + align:start position:0% +of things okay so the question for today + + + align:start position:0% +of things okay so the question for today +what if we want really really big + + align:start position:0% +what if we want really really big + + + align:start position:0% +what if we want really really big +scripts so two and three multi-sig is + + align:start position:0% +scripts so two and three multi-sig is + + + align:start position:0% +scripts so two and three multi-sig is +cool we can just show all three keys and + + align:start position:0% +cool we can just show all three keys and + + + align:start position:0% +cool we can just show all three keys and +there's 33 bytes of data that don't + + align:start position:0% +there's 33 bytes of data that don't + + + align:start position:0% +there's 33 bytes of data that don't +really get used right if you're signing + + align:start position:0% +really get used right if you're signing + + + align:start position:0% +really get used right if you're signing +with two of the three keys well that + + align:start position:0% +with two of the three keys well that + + + align:start position:0% +with two of the three keys well that +means one of the keys never got used it + + align:start position:0% +means one of the keys never got used it + + + align:start position:0% +means one of the keys never got used it +was sort of there and pointless for + + align:start position:0% +was sort of there and pointless for + + + align:start position:0% +was sort of there and pointless for +whatever it's 33 bytes so what if you + + align:start position:0% +whatever it's 33 bytes so what if you + + + align:start position:0% +whatever it's 33 bytes so what if you +want to do like 2 of 50 multi-sig so + + align:start position:0% +want to do like 2 of 50 multi-sig so + + + align:start position:0% +want to do like 2 of 50 multi-sig so +here's 50 different keys any two of + + align:start position:0% +here's 50 different keys any two of + + + align:start position:0% +here's 50 different keys any two of +these people can sign maybe you're in a + + align:start position:0% +these people can sign maybe you're in a + + + align:start position:0% +these people can sign maybe you're in a +company there's 50 employees and the + + align:start position:0% +company there's 50 employees and the + + + align:start position:0% +company there's 50 employees and the +policy is that okay any of these two + + align:start position:0% +policy is that okay any of these two + + + align:start position:0% +policy is that okay any of these two +people can use the coins for this like + + align:start position:0% +people can use the coins for this like + + + align:start position:0% +people can use the coins for this like +you know spending to buy lunch or + + align:start position:0% +you know spending to buy lunch or + + + align:start position:0% +you know spending to buy lunch or +whatever so how would you do to a 50 + + align:start position:0% +whatever so how would you do to a 50 + + + align:start position:0% +whatever so how would you do to a 50 +moles sake + + align:start position:0% +moles sake + + + align:start position:0% +moles sake +any ideas okay you commit and only + + align:start position:0% +any ideas okay you commit and only + + + align:start position:0% +any ideas okay you commit and only +reveal part of a commitment so the cause + + align:start position:0% +reveal part of a commitment so the cause + + + align:start position:0% +reveal part of a commitment so the cause +of in solution to all of luck change + + align:start position:0% +of in solution to all of luck change + + + align:start position:0% +of in solution to all of luck change +problems Merkel trees right that's sort + + align:start position:0% +problems Merkel trees right that's sort + + + align:start position:0% +problems Merkel trees right that's sort +of the solution for all throw a Merkel + + align:start position:0% +of the solution for all throw a Merkel + + + align:start position:0% +of the solution for all throw a Merkel +tree on it which is sort of actually + + align:start position:0% +tree on it which is sort of actually + + + align:start position:0% +tree on it which is sort of actually +what I'm working on now for another + + align:start position:0% +what I'm working on now for another + + + align:start position:0% +what I'm working on now for another +things so yeah you commit to some kind + + align:start position:0% +things so yeah you commit to some kind + + + align:start position:0% +things so yeah you commit to some kind +of route and then you reveal only part + + align:start position:0% +of route and then you reveal only part + + + align:start position:0% +of route and then you reveal only part +of what you've committed to so the idea + + align:start position:0% +of what you've committed to so the idea + + + align:start position:0% +of what you've committed to so the idea +which is from some there's debate about + + align:start position:0% +which is from some there's debate about + + + align:start position:0% +which is from some there's debate about +who came up with this stuff right masked + + align:start position:0% +who came up with this stuff right masked + + + align:start position:0% +who came up with this stuff right masked +like Peter wool was into it but then + + align:start position:0% +like Peter wool was into it but then + + + align:start position:0% +like Peter wool was into it but then +someone else said they wrote a paper + + align:start position:0% +someone else said they wrote a paper + + + align:start position:0% +someone else said they wrote a paper +about it I don't know it was like 2013 + + align:start position:0% +about it I don't know it was like 2013 + + + align:start position:0% +about it I don't know it was like 2013 +2014 the idea the original idea was make + + align:start position:0% +2014 the idea the original idea was make + + + align:start position:0% +2014 the idea the original idea was make +a Merck alized + + align:start position:0% +a Merck alized + + + align:start position:0% +a Merck alized +abstract abstract syntax tree so if you + + align:start position:0% +abstract abstract syntax tree so if you + + + align:start position:0% +abstract abstract syntax tree so if you +have done any like programming language + + align:start position:0% +have done any like programming language + + + align:start position:0% +have done any like programming language +courses + + align:start position:0% +courses + + + align:start position:0% +courses +you probably recognize the term Maps the + + align:start position:0% +you probably recognize the term Maps the + + + align:start position:0% +you probably recognize the term Maps the +abstract syntax tree asked which is sort + + align:start position:0% +abstract syntax tree asked which is sort + + + align:start position:0% +abstract syntax tree asked which is sort +of how compilers work they make this + + align:start position:0% +of how compilers work they make this + + + align:start position:0% +of how compilers work they make this +tree so the idea is okay we'll make + + align:start position:0% +tree so the idea is okay we'll make + + + align:start position:0% +tree so the idea is okay we'll make +every node in that tree like a merkel + + align:start position:0% +every node in that tree like a merkel + + + align:start position:0% +every node in that tree like a merkel +root so every single opcode can be + + align:start position:0% +root so every single opcode can be + + + align:start position:0% +root so every single opcode can be +revealed and be like swapped out and + + align:start position:0% +revealed and be like swapped out and + + + align:start position:0% +revealed and be like swapped out and +it's like super crazy that's + + align:start position:0% +it's like super crazy that's + + + align:start position:0% +it's like super crazy that's +sort of overkill so that was part of the + + align:start position:0% +sort of overkill so that was part of the + + + align:start position:0% +sort of overkill so that was part of the +initial idea and paper but a much + + align:start position:0% +initial idea and paper but a much + + + align:start position:0% +initial idea and paper but a much +simpler way the reason about it and + + align:start position:0% +simpler way the reason about it and + + + align:start position:0% +simpler way the reason about it and +program it would just be okay something + + align:start position:0% +program it would just be okay something + + + align:start position:0% +program it would just be okay something +like pay to script Merkel Ruth where I + + align:start position:0% +like pay to script Merkel Ruth where I + + + align:start position:0% +like pay to script Merkel Ruth where I +in my output script I have a route and + + align:start position:0% +in my output script I have a route and + + + align:start position:0% +in my output script I have a route and +then I reveal that there is a script + + align:start position:0% +then I reveal that there is a script + + + align:start position:0% +then I reveal that there is a script +that goes into that route and then I + + align:start position:0% +that goes into that route and then I + + + align:start position:0% +that goes into that route and then I +execute that script so for example I + + align:start position:0% +execute that script so for example I + + + align:start position:0% +execute that script so for example I +make four different scripts so this + + align:start position:0% +make four different scripts so this + + + align:start position:0% +make four different scripts so this +would be say - wait no anyway it's just + + align:start position:0% +would be say - wait no anyway it's just + + + align:start position:0% +would be say - wait no anyway it's just +for staff a different scripts there's no + + align:start position:0% +for staff a different scripts there's no + + + align:start position:0% +for staff a different scripts there's no +to choose and that results in four right + + align:start position:0% +to choose and that results in four right + + + align:start position:0% +to choose and that results in four right +but you know this is Allison Bob this is + + align:start position:0% +but you know this is Allison Bob this is + + + align:start position:0% +but you know this is Allison Bob this is +Bob Carol this is Carolyn Dave this is + + align:start position:0% +Bob Carol this is Carolyn Dave this is + + + align:start position:0% +Bob Carol this is Carolyn Dave this is +David or something and any of these any + + align:start position:0% +David or something and any of these any + + + align:start position:0% +David or something and any of these any +of these two people but you know four + + align:start position:0% +of these two people but you know four + + + align:start position:0% +of these two people but you know four +different groups can sign and then this + + align:start position:0% +different groups can sign and then this + + + align:start position:0% +different groups can sign and then this +is what you actually put in your output + + align:start position:0% +is what you actually put in your output + + + align:start position:0% +is what you actually put in your output +script and then when you want to spend + + align:start position:0% +script and then when you want to spend + + + align:start position:0% +script and then when you want to spend +you say okay I'm going to provide a + + align:start position:0% +you say okay I'm going to provide a + + + align:start position:0% +you say okay I'm going to provide a +proof so to spend reveal which I'm + + align:start position:0% +proof so to spend reveal which I'm + + + align:start position:0% +proof so to spend reveal which I'm +spending so for example I'm spending + + align:start position:0% +spending so for example I'm spending + + + align:start position:0% +spending so for example I'm spending +using script three and then I reveal a + + align:start position:0% +using script three and then I reveal a + + + align:start position:0% +using script three and then I reveal a +path to the route which would be I + + align:start position:0% +path to the route which would be I + + + align:start position:0% +path to the route which would be I +reveal four and this and then you + + align:start position:0% +reveal four and this and then you + + + align:start position:0% +reveal four and this and then you +compute you say okay hash to these two + + align:start position:0% +compute you say okay hash to these two + + + align:start position:0% +compute you say okay hash to these two +things together get that hash these two + + align:start position:0% +things together get that hash these two + + + align:start position:0% +things together get that hash these two +things together you get that and confirm + + align:start position:0% +things together you get that and confirm + + + align:start position:0% +things together you get that and confirm +that the result is equal to what was in + + align:start position:0% +that the result is equal to what was in + + + align:start position:0% +that the result is equal to what was in +the output script and if it is okay + + align:start position:0% +the output script and if it is okay + + + align:start position:0% +the output script and if it is okay +you've provided a valid proof a valid + + align:start position:0% +you've provided a valid proof a valid + + + align:start position:0% +you've provided a valid proof a valid +inclusion proof that script three was + + align:start position:0% +inclusion proof that script three was + + + align:start position:0% +inclusion proof that script three was +inside this root what's kind of cool in + + align:start position:0% +inside this root what's kind of cool in + + + align:start position:0% +inside this root what's kind of cool in +this case you do not need the binary + + align:start position:0% +this case you do not need the binary + + + align:start position:0% +this case you do not need the binary +tree to be perfect you can have + + align:start position:0% +tree to be perfect you can have + + + align:start position:0% +tree to be perfect you can have +different heights because you're not + + align:start position:0% +different heights because you're not + + + align:start position:0% +different heights because you're not +committing to the height of the tree + + align:start position:0% +committing to the height of the tree + + + align:start position:0% +committing to the height of the tree +when you're sending to it so you could + + align:start position:0% +when you're sending to it so you could + + + align:start position:0% +when you're sending to it so you could +have the you know the default case could + + align:start position:0% +have the you know the default case could + + + align:start position:0% +have the you know the default case could +be here and then a really big tree that + + align:start position:0% +be here and then a really big tree that + + + align:start position:0% +be here and then a really big tree that +goes down a lot over here so these in + + align:start position:0% +goes down a lot over here so these in + + + align:start position:0% +goes down a lot over here so these in +most cases yeah well most cases it's + + align:start position:0% +most cases yeah well most cases it's + + + align:start position:0% +most cases yeah well most cases it's +gonna be Alice and Bob signing and then + + align:start position:0% +gonna be Alice and Bob signing and then + + + align:start position:0% +gonna be Alice and Bob signing and then +Carol and Dave and Edna and whatever are + + align:start position:0% +Carol and Dave and Edna and whatever are + + + align:start position:0% +Carol and Dave and Edna and whatever are +unlikely so I'm gonna put it I'm gonna + + align:start position:0% +unlikely so I'm gonna put it I'm gonna + + + align:start position:0% +unlikely so I'm gonna put it I'm gonna +put Allison Bob here + + align:start position:0% +put Allison Bob here + + + align:start position:0% +put Allison Bob here +and then have the tree sort of + + align:start position:0% +and then have the tree sort of + + + align:start position:0% +and then have the tree sort of +asymmetrically getting longer over here + + align:start position:0% +asymmetrically getting longer over here + + + align:start position:0% +asymmetrically getting longer over here +so that when Alice and Bob sign they can + + align:start position:0% +so that when Alice and Bob sign they can + + + align:start position:0% +so that when Alice and Bob sign they can +just reveal this and then when the other + + align:start position:0% +just reveal this and then when the other + + + align:start position:0% +just reveal this and then when the other +people sign they're gonna have to reveal + + align:start position:0% +people sign they're gonna have to reveal + + + align:start position:0% +people sign they're gonna have to reveal +this and this and then i optimize my + + align:start position:0% +this and this and then i optimize my + + + align:start position:0% +this and this and then i optimize my +myspace for the most likely case so + + align:start position:0% +myspace for the most likely case so + + + align:start position:0% +myspace for the most likely case so +that's kind of cool what else so yeah + + align:start position:0% +that's kind of cool what else so yeah + + + align:start position:0% +that's kind of cool what else so yeah +however there are a probable game + + align:start position:0% +however there are a probable game + + + align:start position:0% +however there are a probable game +there's a bunch of problems one okay two + + align:start position:0% +there's a bunch of problems one okay two + + + align:start position:0% +there's a bunch of problems one okay two +of fifty is cool but what about so in + + align:start position:0% +of fifty is cool but what about so in + + + align:start position:0% +of fifty is cool but what about so in +the case of two of fifty let's just look + + align:start position:0% +the case of two of fifty let's just look + + + align:start position:0% +the case of two of fifty let's just look +through it you know fifty choose two I + + align:start position:0% +through it you know fifty choose two I + + + align:start position:0% +through it you know fifty choose two I +couldn't make the little numbers and + + align:start position:0% +couldn't make the little numbers and + + + align:start position:0% +couldn't make the little numbers and +parentheses the right way so that's a + + align:start position:0% +parentheses the right way so that's a + + + align:start position:0% +parentheses the right way so that's a +thousand two hundred twenty five + + align:start position:0% +thousand two hundred twenty five + + + align:start position:0% +thousand two hundred twenty five +different scripts and that would result + + align:start position:0% +different scripts and that would result + + + align:start position:0% +different scripts and that would result +in it if you do a regular whatever + + align:start position:0% +in it if you do a regular whatever + + + align:start position:0% +in it if you do a regular whatever +regular binary tree balanced I don't I + + align:start position:0% +regular binary tree balanced I don't I + + + align:start position:0% +regular binary tree balanced I don't I +forget all the words you get a tree + + align:start position:0% +forget all the words you get a tree + + + align:start position:0% +forget all the words you get a tree +height of 11 which is like actually kind + + align:start position:0% +height of 11 which is like actually kind + + + align:start position:0% +height of 11 which is like actually kind +of it's like ah so close right if it was + + align:start position:0% +of it's like ah so close right if it was + + + align:start position:0% +of it's like ah so close right if it was +1024 of you ten but a little over and + + align:start position:0% +1024 of you ten but a little over and + + + align:start position:0% +1024 of you ten but a little over and +actually since it doesn't have to be + + align:start position:0% +actually since it doesn't have to be + + + align:start position:0% +actually since it doesn't have to be +symmetric you can get like three high + + align:start position:0% +symmetric you can get like three high + + + align:start position:0% +symmetric you can get like three high +ten for most leaves and then eleven for + + align:start position:0% +ten for most leaves and then eleven for + + + align:start position:0% +ten for most leaves and then eleven for +some of them anyway so your proof size + + align:start position:0% +some of them anyway so your proof size + + + align:start position:0% +some of them anyway so your proof size +is gonna be 352 bytes which is you know + + align:start position:0% +is gonna be 352 bytes which is you know + + + align:start position:0% +is gonna be 352 bytes which is you know +okay and if you didn't use math you can + + align:start position:0% +okay and if you didn't use math you can + + + align:start position:0% +okay and if you didn't use math you can +say well I'm just gonna have a pay to + + align:start position:0% +say well I'm just gonna have a pay to + + + align:start position:0% +say well I'm just gonna have a pay to +script hash and the script is just gonna + + align:start position:0% +script hash and the script is just gonna + + + align:start position:0% +script hash and the script is just gonna +show all 50 keys and have you know opt + + align:start position:0% +show all 50 keys and have you know opt + + + align:start position:0% +show all 50 keys and have you know opt +to all 50 keys op three and that would + + align:start position:0% +to all 50 keys op three and that would + + + align:start position:0% +to all 50 keys op three and that would +be about well plus three or something + + align:start position:0% +be about well plus three or something + + + align:start position:0% +be about well plus three or something +but 1650 bytes so masked is an + + align:start position:0% +but 1650 bytes so masked is an + + + align:start position:0% +but 1650 bytes so masked is an +improvement and it's sort of like hey + + align:start position:0% +improvement and it's sort of like hey + + + align:start position:0% +improvement and it's sort of like hey +I'm doing log n write for all the + + align:start position:0% +I'm doing log n write for all the + + + align:start position:0% +I'm doing log n write for all the +different scripts I have log in if I + + align:start position:0% +different scripts I have log in if I + + + align:start position:0% +different scripts I have log in if I +actually committed to all the thousand + + align:start position:0% +actually committed to all the thousand + + + align:start position:0% +actually committed to all the thousand +two hundred twenty-five scripts with + + align:start position:0% +two hundred twenty-five scripts with + + + align:start position:0% +two hundred twenty-five scripts with +each of the two keys it'd be much bigger + + align:start position:0% +each of the two keys it'd be much bigger + + + align:start position:0% +each of the two keys it'd be much bigger +but I don't actually have to because + + align:start position:0% +but I don't actually have to because + + + align:start position:0% +but I don't actually have to because +I've got this whole 50 choose two in + + align:start position:0% +I've got this whole 50 choose two in + + + align:start position:0% +I've got this whole 50 choose two in +here so I've got two things right I've + + align:start position:0% +here so I've got two things right I've + + + align:start position:0% +here so I've got two things right I've +got this combinatorial thing and then + + align:start position:0% +got this combinatorial thing and then + + + align:start position:0% +got this combinatorial thing and then +this log thing and in balance it's like + + align:start position:0% +this log thing and in balance it's like + + + align:start position:0% +this log thing and in balance it's like +okay man like better but not actually + + align:start position:0% +okay man like better but not actually + + + align:start position:0% +okay man like better but not actually +that awesome right you're going from + + align:start position:0% +that awesome right you're going from + + + align:start position:0% +that awesome right you're going from +thousand 1.6 K to 350 bytes it gets + + align:start position:0% +thousand 1.6 K to 350 bytes it gets + + + align:start position:0% +thousand 1.6 K to 350 bytes it gets +worse let's say I want to do 25 of 50 + + align:start position:0% +worse let's say I want to do 25 of 50 + + + align:start position:0% +worse let's say I want to do 25 of 50 +well that's 50 choose 25 which is around + + align:start position:0% +well that's 50 choose 25 which is around + + + align:start position:0% +well that's 50 choose 25 which is around +100 trillion different combinations the + + align:start position:0% +100 trillion different combinations the + + + align:start position:0% +100 trillion different combinations the +the tree height would not be 47 the + + align:start position:0% +the tree height would not be 47 the + + + align:start position:0% +the tree height would not be 47 the +proof size is gonna be wait did + + align:start position:0% +proof size is gonna be wait did + + + align:start position:0% +proof size is gonna be wait did +do that wrong hold on I think I'm I was + + align:start position:0% +do that wrong hold on I think I'm I was + + + align:start position:0% +do that wrong hold on I think I'm I was +47 by 32 is one 504 okay sorry I just + + align:start position:0% +47 by 32 is one 504 okay sorry I just + + + align:start position:0% +47 by 32 is one 504 okay sorry I just +put 20 I love for some reason I had 22 + + align:start position:0% +put 20 I love for some reason I had 22 + + + align:start position:0% +put 20 I love for some reason I had 22 +there sorry I'll fix that but that is + + align:start position:0% +there sorry I'll fix that but that is + + + align:start position:0% +there sorry I'll fix that but that is +correct yeah one 504 so 1.5 K whereas + + align:start position:0% +correct yeah one 504 so 1.5 K whereas + + + align:start position:0% +correct yeah one 504 so 1.5 K whereas +the raw would still be 1,650 these are + + align:start position:0% +the raw would still be 1,650 these are + + + align:start position:0% +the raw would still be 1,650 these are +about the same this is not a great space + + align:start position:0% +about the same this is not a great space + + + align:start position:0% +about the same this is not a great space +savings right your your proofs are huge + + align:start position:0% +savings right your your proofs are huge + + + align:start position:0% +savings right your your proofs are huge +in fact I would say it's not only not + + align:start position:0% +in fact I would say it's not only not + + + align:start position:0% +in fact I would say it's not only not +much better it's worse right you're + + align:start position:0% +much better it's worse right you're + + + align:start position:0% +much better it's worse right you're +gonna have to compute two hundred + + align:start position:0% +gonna have to compute two hundred + + + align:start position:0% +gonna have to compute two hundred +trillion hashes in order to compute that + + align:start position:0% +trillion hashes in order to compute that + + + align:start position:0% +trillion hashes in order to compute that +root as the person creating the output + + align:start position:0% +root as the person creating the output + + + align:start position:0% +root as the person creating the output +script to verify inclusion you have to + + align:start position:0% +script to verify inclusion you have to + + + align:start position:0% +script to verify inclusion you have to +compute 47 hashes which is fine but 200 + + align:start position:0% +compute 47 hashes which is fine but 200 + + + align:start position:0% +compute 47 hashes which is fine but 200 +rolling hashes is doable but that's + + align:start position:0% +rolling hashes is doable but that's + + + align:start position:0% +rolling hashes is doable but that's +gonna take a while and that's annoying + + align:start position:0% +gonna take a while and that's annoying + + + align:start position:0% +gonna take a while and that's annoying +and yeah how long hours days I don't + + align:start position:0% +and yeah how long hours days I don't + + + align:start position:0% +and yeah how long hours days I don't +know doable but not fun so mass doesn't + + align:start position:0% +know doable but not fun so mass doesn't + + + align:start position:0% +know doable but not fun so mass doesn't +really get you necessarily what you want + + align:start position:0% +really get you necessarily what you want + + + align:start position:0% +really get you necessarily what you want +here although this is kind of a silly + + align:start position:0% +here although this is kind of a silly + + + align:start position:0% +here although this is kind of a silly +case but none of the things really get + + align:start position:0% +case but none of the things really get + + + align:start position:0% +case but none of the things really get +you what you want here because of these + + align:start position:0% +you what you want here because of these + + + align:start position:0% +you what you want here because of these +sort of combinatorial problems okay any + + align:start position:0% +sort of combinatorial problems okay any + + + align:start position:0% +sort of combinatorial problems okay any +questions about or or questions or + + align:start position:0% +questions about or or questions or + + + align:start position:0% +questions about or or questions or +opposition's if I have screwed up some + + align:start position:0% +opposition's if I have screwed up some + + + align:start position:0% +opposition's if I have screwed up some +mess part of it is when you so compare + + align:start position:0% +mess part of it is when you so compare + + + align:start position:0% +mess part of it is when you so compare +these two if I show a tree height of 10 + + align:start position:0% +these two if I show a tree height of 10 + + + align:start position:0% +these two if I show a tree height of 10 +or 11 huh that's weird there's like + + align:start position:0% +or 11 huh that's weird there's like + + + align:start position:0% +or 11 huh that's weird there's like +thousand different scripts around in + + align:start position:0% +thousand different scripts around in + + + align:start position:0% +thousand different scripts around in +this tree if I show a tree height of + + align:start position:0% +this tree if I show a tree height of + + + align:start position:0% +this tree if I show a tree height of +forty seven that's really weird someone + + align:start position:0% +forty seven that's really weird someone + + + align:start position:0% +forty seven that's really weird someone +either was just joking around and made + + align:start position:0% +either was just joking around and made + + + align:start position:0% +either was just joking around and made +this weird sparse tree with all these + + align:start position:0% +this weird sparse tree with all these + + + align:start position:0% +this weird sparse tree with all these +branches to just screw around and have a + + align:start position:0% +branches to just screw around and have a + + + align:start position:0% +branches to just screw around and have a +height of 47 or there's 200 trillion + + align:start position:0% +height of 47 or there's 200 trillion + + + align:start position:0% +height of 47 or there's 200 trillion +possible spending you know outcomes so + + align:start position:0% +possible spending you know outcomes so + + + align:start position:0% +possible spending you know outcomes so +it reveals information about the things + + align:start position:0% +it reveals information about the things + + + align:start position:0% +it reveals information about the things +that were not spent even though it + + align:start position:0% +that were not spent even though it + + + align:start position:0% +that were not spent even though it +doesn't reveal what the scripts were it + + align:start position:0% +doesn't reveal what the scripts were it + + + align:start position:0% +doesn't reveal what the scripts were it +to some extent reveals how many there + + align:start position:0% +to some extent reveals how many there + + + align:start position:0% +to some extent reveals how many there +were okay + + align:start position:0% + + + + align:start position:0% + +so even okay but still it is kind of + + align:start position:0% +so even okay but still it is kind of + + + align:start position:0% +so even okay but still it is kind of +useful right in the - of 50k + + align:start position:0% +useful right in the - of 50k + + + align:start position:0% +useful right in the - of 50k +yes this is better you know you have to + + align:start position:0% +yes this is better you know you have to + + + align:start position:0% +yes this is better you know you have to +compute a couple thousand something + + align:start position:0% +compute a couple thousand something + + + align:start position:0% +compute a couple thousand something +hashes no big deal + + align:start position:0% +hashes no big deal + + + align:start position:0% +hashes no big deal +you you reduce your size from one point + + align:start position:0% +you you reduce your size from one point + + + align:start position:0% +you you reduce your size from one point +6 K to 3 and 52 bytes that's a good deal + + align:start position:0% +6 K to 3 and 52 bytes that's a good deal + + + align:start position:0% +6 K to 3 and 52 bytes that's a good deal +here kind of not but this is also sort + + align:start position:0% +here kind of not but this is also sort + + + align:start position:0% +here kind of not but this is also sort +of a crazy there's other ways to address + + align:start position:0% +of a crazy there's other ways to address + + + align:start position:0% +of a crazy there's other ways to address +this but anyway it's pretty good there's + + align:start position:0% +this but anyway it's pretty good there's + + + align:start position:0% +this but anyway it's pretty good there's +there's sort of two or more than two + + align:start position:0% +there's sort of two or more than two + + + align:start position:0% +there's sort of two or more than two +different ways to implement this you + + align:start position:0% +different ways to implement this you + + + align:start position:0% +different ways to implement this you +could just say okay we're gonna have pay + + align:start position:0% +could just say okay we're gonna have pay + + + align:start position:0% +could just say okay we're gonna have pay +the script Merkel route where you have a + + align:start position:0% +the script Merkel route where you have a + + + align:start position:0% +the script Merkel route where you have a +template where it's like op op two or op + + align:start position:0% +template where it's like op op two or op + + + align:start position:0% +template where it's like op op two or op +of three or something and then some data + + align:start position:0% +of three or something and then some data + + + align:start position:0% +of three or something and then some data +and the idea is when you spend it you + + align:start position:0% +and the idea is when you spend it you + + + align:start position:0% +and the idea is when you spend it you +have to provide a proof and then the + + align:start position:0% +have to provide a proof and then the + + + align:start position:0% +have to provide a proof and then the +script itself and then you execute the + + align:start position:0% +script itself and then you execute the + + + align:start position:0% +script itself and then you execute the +script another way which is kind of cool + + align:start position:0% +script another way which is kind of cool + + + align:start position:0% +script another way which is kind of cool +and people were talking about it + + align:start position:0% +and people were talking about it + + + align:start position:0% +and people were talking about it +recently you have this called tail call + + align:start position:0% +recently you have this called tail call + + + align:start position:0% +recently you have this called tail call +recursion looking thing where the idea + + align:start position:0% +recursion looking thing where the idea + + + align:start position:0% +recursion looking thing where the idea +is if you evaluate your script and then + + align:start position:0% +is if you evaluate your script and then + + + align:start position:0% +is if you evaluate your script and then +there's two items left on the stack at + + align:start position:0% +there's two items left on the stack at + + + align:start position:0% +there's two items left on the stack at +the end what you say is okay the + + align:start position:0% +the end what you say is okay the + + + align:start position:0% +the end what you say is okay the +whichever is bottom or top one of these + + align:start position:0% +whichever is bottom or top one of these + + + align:start position:0% +whichever is bottom or top one of these +items the bottom one is a you know + + align:start position:0% +items the bottom one is a you know + + + align:start position:0% +items the bottom one is a you know +merkel root and then the other odd item + + align:start position:0% +merkel root and then the other odd item + + + align:start position:0% +merkel root and then the other odd item +on the stack is the proof and arguments + + align:start position:0% +on the stack is the proof and arguments + + + align:start position:0% +on the stack is the proof and arguments +you know another script so you can sort + + align:start position:0% +you know another script so you can sort + + + align:start position:0% +you know another script so you can sort +of recursively say okay well i went down + + align:start position:0% +of recursively say okay well i went down + + + align:start position:0% +of recursively say okay well i went down +into this script with this proof and + + align:start position:0% +into this script with this proof and + + + align:start position:0% +into this script with this proof and +then executed it and then things were + + align:start position:0% +then executed it and then things were + + + align:start position:0% +then executed it and then things were +left on the stack and it was another + + align:start position:0% +left on the stack and it was another + + + align:start position:0% +left on the stack and it was another +proof for another merkel root um so + + align:start position:0% +proof for another merkel root um so + + + align:start position:0% +proof for another merkel root um so +that's kind of cool + + align:start position:0% +that's kind of cool + + + align:start position:0% +that's kind of cool +you can make all sorts of crazy things + + align:start position:0% +you can make all sorts of crazy things + + + align:start position:0% +you can make all sorts of crazy things +with that i don't know how useful + + align:start position:0% +with that i don't know how useful + + + align:start position:0% +with that i don't know how useful +recursion recursion is in this case but + + align:start position:0% +recursion recursion is in this case but + + + align:start position:0% +recursion recursion is in this case but +there could be cases you're already in a + + align:start position:0% +there could be cases you're already in a + + + align:start position:0% +there could be cases you're already in a +binary tree so my personal thing is like + + align:start position:0% +binary tree so my personal thing is like + + + align:start position:0% +binary tree so my personal thing is like +why not just keep it simple and pay to a + + align:start position:0% +why not just keep it simple and pay to a + + + align:start position:0% +why not just keep it simple and pay to a +script merkel root but there's people + + align:start position:0% +script merkel root but there's people + + + align:start position:0% +script merkel root but there's people +who they think like no this should be + + align:start position:0% +who they think like no this should be + + + align:start position:0% +who they think like no this should be +more expressive like programming + + align:start position:0% +more expressive like programming + + + align:start position:0% +more expressive like programming +language e wise anyway so that's their + + align:start position:0% +language e wise anyway so that's their + + + align:start position:0% +language e wise anyway so that's their +state of mess mast has code there's a + + align:start position:0% +state of mess mast has code there's a + + + align:start position:0% +state of mess mast has code there's a +pull request and bit right yeah so + + align:start position:0% +pull request and bit right yeah so + + + align:start position:0% +pull request and bit right yeah so +there's some people who are really in + + align:start position:0% +there's some people who are really in + + + align:start position:0% +there's some people who are really in +the mast and like Bitcoin let's make a + + align:start position:0% +the mast and like Bitcoin let's make a + + + align:start position:0% +the mast and like Bitcoin let's make a +soft work and there's also people we're + + align:start position:0% +soft work and there's also people we're + + + align:start position:0% +soft work and there's also people we're +not as enthusiastic and so it's like no + + align:start position:0% +not as enthusiastic and so it's like no + + + align:start position:0% +not as enthusiastic and so it's like no +one's like opposed to it like this is a + + align:start position:0% +one's like opposed to it like this is a + + + align:start position:0% +one's like opposed to it like this is a +bad idea this will break Bitcoin but + + align:start position:0% +bad idea this will break Bitcoin but + + + align:start position:0% +bad idea this will break Bitcoin but +there's dead + + align:start position:0% +there's dead + + + align:start position:0% +there's dead +varying levels of like let's let's get + + align:start position:0% +varying levels of like let's let's get + + + align:start position:0% +varying levels of like let's let's get +this in you can do all these cool things + + align:start position:0% +this in you can do all these cool things + + + align:start position:0% +this in you can do all these cool things +versus and like is this really a + + align:start position:0% +versus and like is this really a + + + align:start position:0% +versus and like is this really a +priority is what are we gonna use with + + align:start position:0% +priority is what are we gonna use with + + + align:start position:0% +priority is what are we gonna use with +it kind of thing okay any questions + + align:start position:0% +it kind of thing okay any questions + + + align:start position:0% +it kind of thing okay any questions +about this I think we have yes + + align:start position:0% +about this I think we have yes + + + align:start position:0% +about this I think we have yes +quick break and then I'll do good off + + align:start position:0% +quick break and then I'll do good off + + + align:start position:0% +quick break and then I'll do good off +return which seems unconnected but I + + align:start position:0% +return which seems unconnected but I + + + align:start position:0% +return which seems unconnected but I +will show you how this connects to these + + align:start position:0% +will show you how this connects to these + + + align:start position:0% +will show you how this connects to these +issues we have + + align:start position:0% +issues we have + + + align:start position:0% +issues we have +okay so I've returned it was in the + + align:start position:0% +okay so I've returned it was in the + + + align:start position:0% +okay so I've returned it was in the +problem set you basically put this + + align:start position:0% +problem set you basically put this + + + align:start position:0% +problem set you basically put this +opcode in the front of your script and + + align:start position:0% +opcode in the front of your script and + + + align:start position:0% +opcode in the front of your script and +that Flags it as forever unspent able as + + align:start position:0% +that Flags it as forever unspent able as + + + align:start position:0% +that Flags it as forever unspent able as +an output so you put shouldn't put much + + align:start position:0% +an output so you put shouldn't put much + + + align:start position:0% +an output so you put shouldn't put much +money into these outputs because they + + align:start position:0% +money into these outputs because they + + + align:start position:0% +money into these outputs because they +are basically destroyed opera turn means + + align:start position:0% +are basically destroyed opera turn means + + + align:start position:0% +are basically destroyed opera turn means +you you know immediately returned from + + align:start position:0% +you you know immediately returned from + + + align:start position:0% +you you know immediately returned from +the the script evaluation and you return + + align:start position:0% +the the script evaluation and you return + + + align:start position:0% +the the script evaluation and you return +a false I think it used to be return + + align:start position:0% +a false I think it used to be return + + + align:start position:0% +a false I think it used to be return +whatever is on the top of the stack + + align:start position:0% +whatever is on the top of the stack + + + align:start position:0% +whatever is on the top of the stack +right which meant you could just spend + + align:start position:0% +right which meant you could just spend + + + align:start position:0% +right which meant you could just spend +anyone's money by using opportunity so + + align:start position:0% +anyone's money by using opportunity so + + + align:start position:0% +anyone's money by using opportunity so +they they they saw fork that to say no + + align:start position:0% +they they they saw fork that to say no + + + align:start position:0% +they they they saw fork that to say no +opera turn always fails instead of opera + + align:start position:0% +opera turn always fails instead of opera + + + align:start position:0% +opera turn always fails instead of opera +turn always tribute Lee succeeds which + + align:start position:0% +turn always tribute Lee succeeds which + + + align:start position:0% +turn always tribute Lee succeeds which +means you just put them up or turn to + + align:start position:0% +means you just put them up or turn to + + + align:start position:0% +means you just put them up or turn to +take anyways money so they figured that + + align:start position:0% +take anyways money so they figured that + + + align:start position:0% +take anyways money so they figured that +one out pretty quick so people use off + + align:start position:0% +one out pretty quick so people use off + + + align:start position:0% +one out pretty quick so people use off +return to put data into the blockchain + + align:start position:0% +return to put data into the blockchain + + + align:start position:0% +return to put data into the blockchain +why do people do this so it doesn't you + + align:start position:0% +why do people do this so it doesn't you + + + align:start position:0% +why do people do this so it doesn't you +know you can't spend it you can't do + + align:start position:0% +know you can't spend it you can't do + + + align:start position:0% +know you can't spend it you can't do +anything with this data but why do + + align:start position:0% +anything with this data but why do + + + align:start position:0% +anything with this data but why do +people do this + + align:start position:0% +people do this + + + align:start position:0% +people do this +it's kind of cool right to prove it's + + align:start position:0% +it's kind of cool right to prove it's + + + align:start position:0% +it's kind of cool right to prove it's +there right they just you want to put + + align:start position:0% +there right they just you want to put + + + align:start position:0% +there right they just you want to put +some data in and you just want to say + + align:start position:0% +some data in and you just want to say + + + align:start position:0% +some data in and you just want to say +hey I thought of this first I'm making a + + align:start position:0% +hey I thought of this first I'm making a + + + align:start position:0% +hey I thought of this first I'm making a +patent or I whatever you put data people + + align:start position:0% +patent or I whatever you put data people + + + align:start position:0% +patent or I whatever you put data people +people use a lot of opera turn people + + align:start position:0% +people use a lot of opera turn people + + + align:start position:0% +people use a lot of opera turn people +what was it like 10 percent yeah so + + align:start position:0% +what was it like 10 percent yeah so + + + align:start position:0% +what was it like 10 percent yeah so +that's + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +so that's a lot of data people using it + + align:start position:0% +so that's a lot of data people using it + + + align:start position:0% +so that's a lot of data people using it +um there's a better way okay so what if + + align:start position:0% +um there's a better way okay so what if + + + align:start position:0% +um there's a better way okay so what if +you wanted to do a zero byte opera turn + + align:start position:0% +you wanted to do a zero byte opera turn + + + align:start position:0% +you wanted to do a zero byte opera turn +it's not quite the same right because an + + align:start position:0% +it's not quite the same right because an + + + align:start position:0% +it's not quite the same right because an +opera turn everyone can see it and in + + align:start position:0% +opera turn everyone can see it and in + + + align:start position:0% +opera turn everyone can see it and in +some cases you might want that you might + + align:start position:0% +some cases you might want that you might + + + align:start position:0% +some cases you might want that you might +want to put an offer turn so that it's + + align:start position:0% +want to put an offer turn so that it's + + + align:start position:0% +want to put an offer turn so that it's +publicly visible but in a lot of cases + + align:start position:0% +publicly visible but in a lot of cases + + + align:start position:0% +publicly visible but in a lot of cases +in most cases I don't care about + + align:start position:0% +in most cases I don't care about + + + align:start position:0% +in most cases I don't care about +someone's random opera turn usually what + + align:start position:0% +someone's random opera turn usually what + + + align:start position:0% +someone's random opera turn usually what +you're putting into opera terms are like + + align:start position:0% +you're putting into opera terms are like + + + align:start position:0% +you're putting into opera terms are like +hashes right because you don't have much + + align:start position:0% +hashes right because you don't have much + + + align:start position:0% +hashes right because you don't have much +space anyway you have like 40 bytes or + + align:start position:0% +space anyway you have like 40 bytes or + + + align:start position:0% +space anyway you have like 40 bytes or +something so usually your space + + align:start position:0% +something so usually your space + + + align:start position:0% +something so usually your space +constrained so you put the hash of some + + align:start position:0% +constrained so you put the hash of some + + + align:start position:0% +constrained so you put the hash of some +document and then someone can prove no + + align:start position:0% +document and then someone can prove no + + + align:start position:0% +document and then someone can prove no +look I put the document on the + + align:start position:0% +look I put the document on the + + + align:start position:0% +look I put the document on the +blockchain by putting the hash of it + + align:start position:0% +blockchain by putting the hash of it + + + align:start position:0% +blockchain by putting the hash of it +that's a commitment to that document + + align:start position:0% +that's a commitment to that document + + + align:start position:0% +that's a commitment to that document +itself so I show that I had this data at + + align:start position:0% +itself so I show that I had this data at + + + align:start position:0% +itself so I show that I had this data at +some time before this block came out + + align:start position:0% +some time before this block came out + + + align:start position:0% +some time before this block came out +right that's essentially what you're + + align:start position:0% +right that's essentially what you're + + + align:start position:0% +right that's essentially what you're +proving you're proving you knew it + + align:start position:0% +proving you're proving you knew it + + + align:start position:0% +proving you're proving you knew it +before a certain time which is it in + + align:start position:0% +before a certain time which is it in + + + align:start position:0% +before a certain time which is it in +many cases really useful I mean that's + + align:start position:0% +many cases really useful I mean that's + + + align:start position:0% +many cases really useful I mean that's +sort of the whole point of the + + align:start position:0% +sort of the whole point of the + + + align:start position:0% +sort of the whole point of the +blockchain to prove that you knew about + + align:start position:0% +blockchain to prove that you knew about + + + align:start position:0% +blockchain to prove that you knew about +this transaction before a future + + align:start position:0% +this transaction before a future + + + align:start position:0% +this transaction before a future +transaction tries to double spend it you + + align:start position:0% +transaction tries to double spend it you + + + align:start position:0% +transaction tries to double spend it you +want to file a patent and hey had this + + align:start position:0% +want to file a patent and hey had this + + + align:start position:0% +want to file a patent and hey had this +idea first or you know prove these + + align:start position:0% +idea first or you know prove these + + + align:start position:0% +idea first or you know prove these +things okay how can we do this with zero + + align:start position:0% +things okay how can we do this with zero + + + align:start position:0% +things okay how can we do this with zero +bytes overhead okay you put it in the + + align:start position:0% +bytes overhead okay you put it in the + + + align:start position:0% +bytes overhead okay you put it in the +signature and this was not obvious and + + align:start position:0% +signature and this was not obvious and + + + align:start position:0% +signature and this was not obvious and +like no one thought of this until a year + + align:start position:0% +like no one thought of this until a year + + + align:start position:0% +like no one thought of this until a year +or two ago I think it was an upholsterer + + align:start position:0% +or two ago I think it was an upholsterer + + + align:start position:0% +or two ago I think it was an upholsterer +but I could be wrong but I just + + align:start position:0% +but I could be wrong but I just + + + align:start position:0% +but I could be wrong but I just +associate it with him because he worked + + align:start position:0% +associate it with him because he worked + + + align:start position:0% +associate it with him because he worked +on it but I'm not a hundred percent sure + + align:start position:0% +on it but I'm not a hundred percent sure + + + align:start position:0% +on it but I'm not a hundred percent sure +and he called it pay to contract hash + + align:start position:0% +and he called it pay to contract hash + + + align:start position:0% +and he called it pay to contract hash +which is confusing it's not a it's not + + align:start position:0% +which is confusing it's not a it's not + + + align:start position:0% +which is confusing it's not a it's not +at all the same as fada script hash it's + + align:start position:0% +at all the same as fada script hash it's + + + align:start position:0% +at all the same as fada script hash it's +not at all the same as paid a puppy ash + + align:start position:0% +not at all the same as paid a puppy ash + + + align:start position:0% +not at all the same as paid a puppy ash +but it's called paid a contract hash + + align:start position:0% +but it's called paid a contract hash + + + align:start position:0% +but it's called paid a contract hash +which makes it really confusing Bitcoin + + align:start position:0% +which makes it really confusing Bitcoin + + + align:start position:0% +which makes it really confusing Bitcoin +has really confusing names right like + + align:start position:0% +has really confusing names right like + + + align:start position:0% +has really confusing names right like +scripts it or pub key script wait script + + align:start position:0% +scripts it or pub key script wait script + + + align:start position:0% +scripts it or pub key script wait script +pub key script pub key does not have to + + align:start position:0% +pub key script pub key does not have to + + + align:start position:0% +pub key script pub key does not have to +have a pub key in it in most cases it + + align:start position:0% +have a pub key in it in most cases it + + + align:start position:0% +have a pub key in it in most cases it +doesn't it has a funky hash or a script + + align:start position:0% +doesn't it has a funky hash or a script + + + align:start position:0% +doesn't it has a funky hash or a script +hash it doesn't have to have anything in + + align:start position:0% +hash it doesn't have to have anything in + + + align:start position:0% +hash it doesn't have to have anything in +it but it's called screw + + align:start position:0% +it but it's called screw + + + align:start position:0% +it but it's called screw +Punkie and then script sig usually has + + align:start position:0% +Punkie and then script sig usually has + + + align:start position:0% +Punkie and then script sig usually has +signatures but again not always and + + align:start position:0% +signatures but again not always and + + + align:start position:0% +signatures but again not always and +there's all sorts of confusing names + + align:start position:0% +there's all sorts of confusing names + + + align:start position:0% +there's all sorts of confusing names +anyway here's our new contribution to + + align:start position:0% +anyway here's our new contribution to + + + align:start position:0% +anyway here's our new contribution to +confusing names kay to contract hash + + align:start position:0% +confusing names kay to contract hash + + + align:start position:0% +confusing names kay to contract hash +which is not really paying to anything + + align:start position:0% +which is not really paying to anything + + + align:start position:0% +which is not really paying to anything +there doesn't have to be a contract + + align:start position:0% +there doesn't have to be a contract + + + align:start position:0% +there doesn't have to be a contract +there is a hash involved but yeah okay + + align:start position:0% +there is a hash involved but yeah okay + + + align:start position:0% +there is a hash involved but yeah okay +so it's a weird name as you can't + + align:start position:0% +so it's a weird name as you can't + + + align:start position:0% +so it's a weird name as you can't +actually detect the contract you know + + align:start position:0% +actually detect the contract you know + + + align:start position:0% +actually detect the contract you know +paying to it but okay to review a + + align:start position:0% +paying to it but okay to review a + + + align:start position:0% +paying to it but okay to review a +snorrison I'm gonna use snore signatures + + align:start position:0% +snorrison I'm gonna use snore signatures + + + align:start position:0% +snorrison I'm gonna use snore signatures +this still works in ECDSA but you see + + align:start position:0% +this still works in ECDSA but you see + + + align:start position:0% +this still works in ECDSA but you see +the SA is weird annoying and it also + + align:start position:0% +the SA is weird annoying and it also + + + align:start position:0% +the SA is weird annoying and it also +makes more sense than Schnoor signatures + + align:start position:0% +makes more sense than Schnoor signatures + + + align:start position:0% +makes more sense than Schnoor signatures +so I'll explain that but but it totally + + align:start position:0% +so I'll explain that but but it totally + + + align:start position:0% +so I'll explain that but but it totally +works in EC it is DSA today so the idea + + align:start position:0% +works in EC it is DSA today so the idea + + + align:start position:0% +works in EC it is DSA today so the idea +of the short signature is okay this is + + align:start position:0% +of the short signature is okay this is + + + align:start position:0% +of the short signature is okay this is +my private key this is the message I + + align:start position:0% +my private key this is the message I + + + align:start position:0% +my private key this is the message I +want to sign this is a random sort of + + align:start position:0% +want to sign this is a random sort of + + + align:start position:0% +want to sign this is a random sort of +temporary private key I come up with and + + align:start position:0% +temporary private key I come up with and + + + align:start position:0% +temporary private key I come up with and +then this is that temporary private key + + align:start position:0% +then this is that temporary private key + + + align:start position:0% +then this is that temporary private key +turned into a public key write x Gina + + align:start position:0% +turned into a public key write x Gina + + + align:start position:0% +turned into a public key write x Gina +gets the public key version and then two + + align:start position:0% +gets the public key version and then two + + + align:start position:0% +gets the public key version and then two +to evaluate two to verify the signature + + align:start position:0% +to evaluate two to verify the signature + + + align:start position:0% +to evaluate two to verify the signature +you just multiply both sides by G so you + + align:start position:0% +you just multiply both sides by G so you + + + align:start position:0% +you just multiply both sides by G so you +get s times G K turns into our little a + + align:start position:0% +get s times G K turns into our little a + + + align:start position:0% +get s times G K turns into our little a +turns into big a this is just the hash + + align:start position:0% +turns into big a this is just the hash + + + align:start position:0% +turns into big a this is just the hash +32-byte hash so it's it stays the same + + align:start position:0% +32-byte hash so it's it stays the same + + + align:start position:0% +32-byte hash so it's it stays the same +so the signature is R and s the sorry + + align:start position:0% +so the signature is R and s the sorry + + + align:start position:0% +so the signature is R and s the sorry +the R and s so the signature and the + + align:start position:0% +the R and s so the signature and the + + + align:start position:0% +the R and s so the signature and the +pump key is a and the message is out + + align:start position:0% +pump key is a and the message is out + + + align:start position:0% +pump key is a and the message is out +okay so that's the signing or close + + align:start position:0% +okay so that's the signing or close + + + align:start position:0% +okay so that's the signing or close +enough to the signing that's using + + align:start position:0% +enough to the signing that's using + + + align:start position:0% +enough to the signing that's using +Bitcoin so pay to pub paid to contract + + align:start position:0% +Bitcoin so pay to pub paid to contract + + + align:start position:0% +Bitcoin so pay to pub paid to contract +hash says okay I want to put our betray + + align:start position:0% +hash says okay I want to put our betray + + + align:start position:0% +hash says okay I want to put our betray +data into my signature in a way that I + + align:start position:0% +data into my signature in a way that I + + + align:start position:0% +data into my signature in a way that I +can prove it was there so here's the + + align:start position:0% +can prove it was there so here's the + + + align:start position:0% +can prove it was there so here's the +normal equation now what if I redefined + + align:start position:0% +normal equation now what if I redefined + + + align:start position:0% +normal equation now what if I redefined +K normally K is just a random number but + + align:start position:0% +K normally K is just a random number but + + + align:start position:0% +K normally K is just a random number but +now I'm gonna redefine k k is now J so J + + align:start position:0% +now I'm gonna redefine k k is now J so J + + + align:start position:0% +now I'm gonna redefine k k is now J so J +is my new real random number and then + + align:start position:0% +is my new real random number and then + + + align:start position:0% +is my new real random number and then +I'm going to add the Hat no there's no G + + align:start position:0% +I'm going to add the Hat no there's no G + + + align:start position:0% +I'm going to add the Hat no there's no G +there shoot anyway G you should not be + + align:start position:0% +there shoot anyway G you should not be + + + align:start position:0% +there shoot anyway G you should not be +there but it should be there sorry okay + + align:start position:0% +there but it should be there sorry okay + + + align:start position:0% +there but it should be there sorry okay +they so I redefined K as J which is an + + align:start position:0% +they so I redefined K as J which is an + + + align:start position:0% +they so I redefined K as J which is an +actual random number + + align:start position:0% +actual random number + + + align:start position:0% +actual random number +plus the hash of the data I want to + + align:start position:0% +plus the hash of the data I want to + + + align:start position:0% +plus the hash of the data I want to +commit to and J times G I think yeah + + align:start position:0% + + + + align:start position:0% + +yeah anyway and then the signature it's + + align:start position:0% +yeah anyway and then the signature it's + + + align:start position:0% +yeah anyway and then the signature it's +still the same equation right I'm just + + align:start position:0% +still the same equation right I'm just + + + align:start position:0% +still the same equation right I'm just +saying okay it's this new K minus this + + align:start position:0% +saying okay it's this new K minus this + + + align:start position:0% +saying okay it's this new K minus this +thing and so nobody necessarily knows + + align:start position:0% +thing and so nobody necessarily knows + + + align:start position:0% +thing and so nobody necessarily knows +that I'm doing this right if I just tell + + align:start position:0% +that I'm doing this right if I just tell + + + align:start position:0% +that I'm doing this right if I just tell +you okay you know if I just tell you R + + align:start position:0% +you okay you know if I just tell you R + + + align:start position:0% +you okay you know if I just tell you R +and s the equation still holds + + align:start position:0% +and s the equation still holds + + + align:start position:0% +and s the equation still holds +it's just that K is a little special + + align:start position:0% +it's just that K is a little special + + + align:start position:0% +it's just that K is a little special +right i-44 anyone else it looks like a + + align:start position:0% +right i-44 anyone else it looks like a + + + align:start position:0% +right i-44 anyone else it looks like a +random number right it's a random number + + align:start position:0% +random number right it's a random number + + + align:start position:0% +random number right it's a random number +plus this other hash not times G so it's + + align:start position:0% +plus this other hash not times G so it's + + + align:start position:0% +plus this other hash not times G so it's +a random number plus a hash which hashes + + align:start position:0% +a random number plus a hash which hashes + + + align:start position:0% +a random number plus a hash which hashes +look pretty random so it's a random + + align:start position:0% +look pretty random so it's a random + + + align:start position:0% +look pretty random so it's a random +number plus some other random number + + align:start position:0% +number plus some other random number + + + align:start position:0% +number plus some other random number +no one's gonna sell that anything's + + align:start position:0% +no one's gonna sell that anything's + + + align:start position:0% +no one's gonna sell that anything's +weird about this however it is unique in + + align:start position:0% +weird about this however it is unique in + + + align:start position:0% +weird about this however it is unique in +that I've got this random number plus + + align:start position:0% +that I've got this random number plus + + + align:start position:0% +that I've got this random number plus +the hash of that random number times G + + align:start position:0% +the hash of that random number times G + + + align:start position:0% +the hash of that random number times G +in it and this extra data I put in okay + + align:start position:0% +in it and this extra data I put in okay + + + align:start position:0% +in it and this extra data I put in okay +so to verify if I don't tell you about + + align:start position:0% +so to verify if I don't tell you about + + + align:start position:0% +so to verify if I don't tell you about +this verification looks the same + + align:start position:0% +this verification looks the same + + + align:start position:0% +this verification looks the same +what if I do tell you about it though so + + align:start position:0% +what if I do tell you about it though so + + + align:start position:0% +what if I do tell you about it though so +normally this thing RS pump use a + + align:start position:0% +normally this thing RS pump use a + + + align:start position:0% +normally this thing RS pump use a +message exam but the signer can prove + + align:start position:0% +message exam but the signer can prove + + + align:start position:0% +message exam but the signer can prove +that r is not kg that there's this other + + align:start position:0% +that r is not kg that there's this other + + + align:start position:0% +that r is not kg that there's this other +K and you know that well it's K but + + align:start position:0% +K and you know that well it's K but + + + align:start position:0% +K and you know that well it's K but +there's something else in our I can + + align:start position:0% +there's something else in our I can + + + align:start position:0% +there's something else in our I can +prove that r is special after the fact + + align:start position:0% +prove that r is special after the fact + + + align:start position:0% +prove that r is special after the fact +right everyone knows what R is but I can + + align:start position:0% +right everyone knows what R is but I can + + + align:start position:0% +right everyone knows what R is but I can +then prove that something was in are + + align:start position:0% +then prove that something was in are + + + align:start position:0% +then prove that something was in are +also never reveal K even after the fact + + align:start position:0% +also never reveal K even after the fact + + + align:start position:0% +also never reveal K even after the fact +that'll let you figure out the person's + + align:start position:0% +that'll let you figure out the person's + + + align:start position:0% +that'll let you figure out the person's +private key so the idea is I can prove + + align:start position:0% +private key so the idea is I can prove + + + align:start position:0% +private key so the idea is I can prove +that R equals j plus the hash of the + + align:start position:0% +that R equals j plus the hash of the + + + align:start position:0% +that R equals j plus the hash of the +data and j times G here's where it's a + + align:start position:0% +data and j times G here's where it's a + + + align:start position:0% +data and j times G here's where it's a +little confusing right because this is + + align:start position:0% +little confusing right because this is + + + align:start position:0% +little confusing right because this is +this is already pub key and you're + + align:start position:0% +this is already pub key and you're + + + align:start position:0% +this is already pub key and you're +multiplying by G again right so that's + + align:start position:0% +multiplying by G again right so that's + + + align:start position:0% +multiplying by G again right so that's +where this is you know anyone can + + align:start position:0% +where this is you know anyone can + + + align:start position:0% +where this is you know anyone can +compute this right because I can say hey + + align:start position:0% +compute this right because I can say hey + + + align:start position:0% +compute this right because I can say hey +here's you already know our I can give + + align:start position:0% +here's you already know our I can give + + + align:start position:0% +here's you already know our I can give +you a J and some data such that J plus + + align:start position:0% +you a J and some data such that J plus + + + align:start position:0% +you a J and some data such that J plus +the hash of this data and J itself times + + align:start position:0% +the hash of this data and J itself times + + + align:start position:0% +the hash of this data and J itself times +G equals R + + align:start position:0% +G equals R + + + align:start position:0% +G equals R +I can't Forge this right if I try to + + align:start position:0% +I can't Forge this right if I try to + + + align:start position:0% +I can't Forge this right if I try to +forge this I say after the fact I want + + align:start position:0% +forge this I say after the fact I want + + + align:start position:0% +forge this I say after the fact I want +to come up with I just made our randomly + + align:start position:0% +to come up with I just made our randomly + + + align:start position:0% +to come up with I just made our randomly +right I didn't have any actual data and + + align:start position:0% +right I didn't have any actual data and + + + align:start position:0% +right I didn't have any actual data and +then after the fact I want to come up + + align:start position:0% +then after the fact I want to come up + + + align:start position:0% +then after the fact I want to come up +and then lie and say ya know I put this + + align:start position:0% +and then lie and say ya know I put this + + + align:start position:0% +and then lie and say ya know I put this +data in to this are okay now we need to + + align:start position:0% +data in to this are okay now we need to + + + align:start position:0% +data in to this are okay now we need to +solve for J right because my proof is + + align:start position:0% +solve for J right because my proof is + + + align:start position:0% +solve for J right because my proof is +gonna be J in this data so I've got the + + align:start position:0% +gonna be J in this data so I've got the + + + align:start position:0% +gonna be J in this data so I've got the +data I want and I want to figure out + + align:start position:0% +data I want and I want to figure out + + + align:start position:0% +data I want and I want to figure out +what J's so J is the hash of this data + + align:start position:0% +what J's so J is the hash of this data + + + align:start position:0% +what J's so J is the hash of this data +and J times G minus R oh shoot right + + align:start position:0% +and J times G minus R oh shoot right + + + align:start position:0% +and J times G minus R oh shoot right +that would be the equation I have to + + align:start position:0% +that would be the equation I have to + + + align:start position:0% +that would be the equation I have to +solve if I want to falsely prove that + + align:start position:0% +solve if I want to falsely prove that + + + align:start position:0% +solve if I want to falsely prove that +this data went into it the problem is + + align:start position:0% +this data went into it the problem is + + + align:start position:0% +this data went into it the problem is +I've got this thing where it's like J is + + align:start position:0% +I've got this thing where it's like J is + + + align:start position:0% +I've got this thing where it's like J is +defined in terms of the hash of J I + + align:start position:0% +defined in terms of the hash of J I + + + align:start position:0% +defined in terms of the hash of J I +don't I don't that's that's gonna be + + align:start position:0% +don't I don't that's that's gonna be + + + align:start position:0% +don't I don't that's that's gonna be +hard right if I'm defining J in terms of + + align:start position:0% +hard right if I'm defining J in terms of + + + align:start position:0% +hard right if I'm defining J in terms of +the hash of J I'm stuck because that's + + align:start position:0% +the hash of J I'm stuck because that's + + + align:start position:0% +the hash of J I'm stuck because that's +not how hash functions don't let me do + + align:start position:0% +not how hash functions don't let me do + + + align:start position:0% +not how hash functions don't let me do +that so this is actually kind of cool + + align:start position:0% +that so this is actually kind of cool + + + align:start position:0% +that so this is actually kind of cool +because it's a proof that there was some + + align:start position:0% +because it's a proof that there was some + + + align:start position:0% +because it's a proof that there was some +extra data that went in to the random R + + align:start position:0% +extra data that went in to the random R + + + align:start position:0% +extra data that went in to the random R +point before the signing happened right + + align:start position:0% +point before the signing happened right + + + align:start position:0% +point before the signing happened right +or well it's yeah it had to be before + + align:start position:0% +or well it's yeah it had to be before + + + align:start position:0% +or well it's yeah it had to be before +the signing happened because the + + align:start position:0% +the signing happened because the + + + align:start position:0% +the signing happened because the +signature has are in it and s is a + + align:start position:0% +signature has are in it and s is a + + + align:start position:0% +signature has are in it and s is a +function of r and this is cool because + + align:start position:0% +function of r and this is cool because + + + align:start position:0% +function of r and this is cool because +if you don't know about it it just looks + + align:start position:0% +if you don't know about it it just looks + + + align:start position:0% +if you don't know about it it just looks +like a regular signature with a like + + align:start position:0% +like a regular signature with a like + + + align:start position:0% +like a regular signature with a like +regular R value but if I tell you about + + align:start position:0% +regular R value but if I tell you about + + + align:start position:0% +regular R value but if I tell you about +it I was like yeah when I sign that I + + align:start position:0% +it I was like yeah when I sign that I + + + align:start position:0% +it I was like yeah when I sign that I +actually put some extra data into here + + align:start position:0% +actually put some extra data into here + + + align:start position:0% +actually put some extra data into here +so that's kind of better than off return + + align:start position:0% +so that's kind of better than off return + + + align:start position:0% +so that's kind of better than off return +right there's zero bytes overhead you're + + align:start position:0% +right there's zero bytes overhead you're + + + align:start position:0% +right there's zero bytes overhead you're +gonna sign anyway so you can put data + + align:start position:0% +gonna sign anyway so you can put data + + + align:start position:0% +gonna sign anyway so you can put data +inside a signatures are point you can + + align:start position:0% +inside a signatures are point you can + + + align:start position:0% +inside a signatures are point you can +even do it with other people's + + align:start position:0% +even do it with other people's + + + align:start position:0% +even do it with other people's +signatures there's no real private + + align:start position:0% +signatures there's no real private + + + align:start position:0% +signatures there's no real private +information here if I just can use some + + align:start position:0% +information here if I just can use some + + + align:start position:0% +information here if I just can use some +data it's totally safe right hey here's + + align:start position:0% +data it's totally safe right hey here's + + + align:start position:0% +data it's totally safe right hey here's +some data okay here's the J point that + + align:start position:0% +some data okay here's the J point that + + + align:start position:0% +some data okay here's the J point that +goes in that you know constructs this + + align:start position:0% +goes in that you know constructs this + + + align:start position:0% +goes in that you know constructs this +and they are like okay sounds good + + align:start position:0% +and they are like okay sounds good + + + align:start position:0% +and they are like okay sounds good +I can put someone else's data into this + + align:start position:0% +I can put someone else's data into this + + + align:start position:0% +I can put someone else's data into this +you just handle the data they give you + + align:start position:0% +you just handle the data they give you + + + align:start position:0% +you just handle the data they give you +the proof which in that case is just J + + align:start position:0% +the proof which in that case is just J + + + align:start position:0% +the proof which in that case is just J +so it's upper turn with zero byte + + align:start position:0% +so it's upper turn with zero byte + + + align:start position:0% +so it's upper turn with zero byte +overhead this is really cool I believe + + align:start position:0% +overhead this is really cool I believe + + + align:start position:0% +overhead this is really cool I believe +this is being used for like open + + align:start position:0% +this is being used for like open + + + align:start position:0% +this is being used for like open +timestamps now as of a few I think right + + align:start position:0% + + + + align:start position:0% + +but but it's also nice it's not like a + + align:start position:0% +but but it's also nice it's not like a + + + align:start position:0% +but but it's also nice it's not like a +soft pork or anything this is just a fun + + align:start position:0% +soft pork or anything this is just a fun + + + align:start position:0% +soft pork or anything this is just a fun +trick you can do with your signatures so + + align:start position:0% +trick you can do with your signatures so + + + align:start position:0% +trick you can do with your signatures so +you can do this today if you want it and + + align:start position:0% +you can do this today if you want it and + + + align:start position:0% +you can do this today if you want it and +then prove to people later like hey I + + align:start position:0% +then prove to people later like hey I + + + align:start position:0% +then prove to people later like hey I +put my name into my signature direct + + align:start position:0% +put my name into my signature direct + + + align:start position:0% +put my name into my signature direct +replacement for the operator you you + + align:start position:0% +replacement for the operator you you + + + align:start position:0% +replacement for the operator you you +commit to the route right see so in + + align:start position:0% +commit to the route right see so in + + + align:start position:0% +commit to the route right see so in +their case this data is the Merkel route + + align:start position:0% +their case this data is the Merkel route + + + align:start position:0% +their case this data is the Merkel route +and then you can then prove so you can + + align:start position:0% +and then you can then prove so you can + + + align:start position:0% +and then you can then prove so you can +you know put a Merkel route here and + + align:start position:0% +you know put a Merkel route here and + + + align:start position:0% +you know put a Merkel route here and +then I prove that there's a Merkel route + + align:start position:0% +then I prove that there's a Merkel route + + + align:start position:0% +then I prove that there's a Merkel route +inside my signature and then I also + + align:start position:0% +inside my signature and then I also + + + align:start position:0% +inside my signature and then I also +prove a branch so that the data is in + + align:start position:0% +prove a branch so that the data is in + + + align:start position:0% +prove a branch so that the data is in +the Merkel route which is then in the + + align:start position:0% +the Merkel route which is then in the + + + align:start position:0% +the Merkel route which is then in the +our point which is in the signature + + align:start position:0% +our point which is in the signature + + + align:start position:0% +our point which is in the signature +which is in the blocks Merkel tree which + + align:start position:0% +which is in the blocks Merkel tree which + + + align:start position:0% +which is in the blocks Merkel tree which +is in the blockchain so you've got like + + align:start position:0% +is in the blockchain so you've got like + + + align:start position:0% +is in the blockchain so you've got like +four or five different proofs going on + + align:start position:0% +four or five different proofs going on + + + align:start position:0% +four or five different proofs going on +but they should all be working okay so + + align:start position:0% +but they should all be working okay so + + + align:start position:0% +but they should all be working okay so +this is this is kind of cool any idea + + align:start position:0% +this is this is kind of cool any idea + + + align:start position:0% +this is this is kind of cool any idea +why I was explaining all this in terms + + align:start position:0% +why I was explaining all this in terms + + + align:start position:0% +why I was explaining all this in terms +of like mast and multi-sig like these + + align:start position:0% +of like mast and multi-sig like these + + + align:start position:0% +of like mast and multi-sig like these +seem totally unconnected right any idea + + align:start position:0% +seem totally unconnected right any idea + + + align:start position:0% +seem totally unconnected right any idea +so yeah it took Bitcoin people like well + + align:start position:0% +so yeah it took Bitcoin people like well + + + align:start position:0% +so yeah it took Bitcoin people like well +over a year to see the after the you + + align:start position:0% +over a year to see the after the you + + + align:start position:0% +over a year to see the after the you +know in retrospect really obvious + + align:start position:0% +know in retrospect really obvious + + + align:start position:0% +know in retrospect really obvious +connection and thing to do with this + + align:start position:0% +connection and thing to do with this + + + align:start position:0% +connection and thing to do with this +but it took a year or two and then + + align:start position:0% +but it took a year or two and then + + + align:start position:0% +but it took a year or two and then +someone Greg posted on the mailing list + + align:start position:0% +someone Greg posted on the mailing list + + + align:start position:0% +someone Greg posted on the mailing list +in January like hey wait you can use + + align:start position:0% +in January like hey wait you can use + + + align:start position:0% +in January like hey wait you can use +this for something else and then it was + + align:start position:0% +this for something else and then it was + + + align:start position:0% +this for something else and then it was +like oh shoot like how did no one think + + align:start position:0% +like oh shoot like how did no one think + + + align:start position:0% +like oh shoot like how did no one think +of that + + align:start position:0% +of that + + + align:start position:0% +of that +so it's called tap root and I don't know + + align:start position:0% +so it's called tap root and I don't know + + + align:start position:0% +so it's called tap root and I don't know +why Greg called it that Greg Maxwell + + align:start position:0% +why Greg called it that Greg Maxwell + + + align:start position:0% +why Greg called it that Greg Maxwell +he's got was a big beard who works on + + align:start position:0% +he's got was a big beard who works on + + + align:start position:0% +he's got was a big beard who works on +Bitcoin he's super smart and stuff and + + align:start position:0% +Bitcoin he's super smart and stuff and + + + align:start position:0% +Bitcoin he's super smart and stuff and +it uses this pay to contract hash + + align:start position:0% +it uses this pay to contract hash + + + align:start position:0% +it uses this pay to contract hash +construction and it's the same equation + + align:start position:0% +construction and it's the same equation + + + align:start position:0% +construction and it's the same equation +but it took us a year or two to figure + + align:start position:0% +but it took us a year or two to figure + + + align:start position:0% +but it took us a year or two to figure +out that you can do this so the + + align:start position:0% +out that you can do this so the + + + align:start position:0% +out that you can do this so the +motivation here is paid a pub key hash + + align:start position:0% +motivation here is paid a pub key hash + + + align:start position:0% +motivation here is paid a pub key hash +and pay to script hash look different + + align:start position:0% +and pay to script hash look different + + + align:start position:0% +and pay to script hash look different +right you can tell just looking at the + + align:start position:0% +right you can tell just looking at the + + + align:start position:0% +right you can tell just looking at the +output these are totally different you + + align:start position:0% +output these are totally different you + + + align:start position:0% +output these are totally different you +know output scripts one of them's got a + + align:start position:0% +know output scripts one of them's got a + + + align:start position:0% +know output scripts one of them's got a +pub - one of them's got a script - + + align:start position:0% +pub - one of them's got a script - + + + align:start position:0% +pub - one of them's got a script - +different + + align:start position:0% +different + + + align:start position:0% +different +we don't want everything to look + + align:start position:0% +we don't want everything to look + + + align:start position:0% +we don't want everything to look +different then you can sort of sort + + align:start position:0% +different then you can sort of sort + + + align:start position:0% +different then you can sort of sort +things you can try to differentiate try + + align:start position:0% +things you can try to differentiate try + + + align:start position:0% +things you can try to differentiate try +to track people's coins things like that + + align:start position:0% +to track people's coins things like that + + + align:start position:0% +to track people's coins things like that +you want it to all look uniform to make + + align:start position:0% +you want it to all look uniform to make + + + align:start position:0% +you want it to all look uniform to make +it more anonymous so one thing you could + + align:start position:0% +it more anonymous so one thing you could + + + align:start position:0% +it more anonymous so one thing you could +do is just use pay to script - for + + align:start position:0% +do is just use pay to script - for + + + align:start position:0% +do is just use pay to script - for +everything you can put a pump key you + + align:start position:0% +everything you can put a pump key you + + + align:start position:0% +everything you can put a pump key you +know single essentially one of one + + align:start position:0% +know single essentially one of one + + + align:start position:0% +know single essentially one of one +multi-sig or just just the beta script + + align:start position:0% +multi-sig or just just the beta script + + + align:start position:0% +multi-sig or just just the beta script +hash pay to pub key hash script in paid + + align:start position:0% +hash pay to pub key hash script in paid + + + align:start position:0% +hash pay to pub key hash script in paid +a script hash you wouldn't do that you + + align:start position:0% +a script hash you wouldn't do that you + + + align:start position:0% +a script hash you wouldn't do that you +just have you'd have that you'd have the + + align:start position:0% +just have you'd have that you'd have the + + + align:start position:0% +just have you'd have that you'd have the +direct pay to pub key put into a script + + align:start position:0% +direct pay to pub key put into a script + + + align:start position:0% +direct pay to pub key put into a script +hash so that like it looks like a script + + align:start position:0% +hash so that like it looks like a script + + + align:start position:0% +hash so that like it looks like a script +- and then the script is public key up + + align:start position:0% +- and then the script is public key up + + + align:start position:0% +- and then the script is public key up +check sig it's actually not really any + + align:start position:0% +check sig it's actually not really any + + + align:start position:0% +check sig it's actually not really any +overhead I think you actually save a + + align:start position:0% +overhead I think you actually save a + + + align:start position:0% +overhead I think you actually save a +bite or two nobody does that + + align:start position:0% +bite or two nobody does that + + + align:start position:0% +bite or two nobody does that +you could that might solve like 80% of + + align:start position:0% +you could that might solve like 80% of + + + align:start position:0% +you could that might solve like 80% of +what this is trying to solve it's but + + align:start position:0% +what this is trying to solve it's but + + + align:start position:0% +what this is trying to solve it's but +it's kind of boring it doesn't use cool + + align:start position:0% +it's kind of boring it doesn't use cool + + + align:start position:0% +it's kind of boring it doesn't use cool +math so anyway okay the other the other + + align:start position:0% +math so anyway okay the other the other + + + align:start position:0% +math so anyway okay the other the other +the other observation is that in most + + align:start position:0% +the other observation is that in most + + + align:start position:0% +the other observation is that in most +cases scripts you have these sort of + + align:start position:0% +cases scripts you have these sort of + + + align:start position:0% +cases scripts you have these sort of +scripts and there's a hidden option + + align:start position:0% +scripts and there's a hidden option + + + align:start position:0% +scripts and there's a hidden option +which is or everyone signs so in the + + align:start position:0% +which is or everyone signs so in the + + + align:start position:0% +which is or everyone signs so in the +case of like two of 50 multi say well if + + align:start position:0% +case of like two of 50 multi say well if + + + align:start position:0% +case of like two of 50 multi say well if +all 50 people sign that's okay right + + align:start position:0% +all 50 people sign that's okay right + + + align:start position:0% +all 50 people sign that's okay right +that's no worse so if it's 25 of 50 + + align:start position:0% +that's no worse so if it's 25 of 50 + + + align:start position:0% +that's no worse so if it's 25 of 50 +multi-sig if all 50 people happen to + + align:start position:0% +multi-sig if all 50 people happen to + + + align:start position:0% +multi-sig if all 50 people happen to +sign sure that's you know it's no loss + + align:start position:0% +sign sure that's you know it's no loss + + + align:start position:0% +sign sure that's you know it's no loss +of security so the idea is you use this + + align:start position:0% +of security so the idea is you use this + + + align:start position:0% +of security so the idea is you use this +pay to script paid a contract hashed + + align:start position:0% +pay to script paid a contract hashed + + + align:start position:0% +pay to script paid a contract hashed +instruction to merge Paytas pub key hash + + align:start position:0% +instruction to merge Paytas pub key hash + + + align:start position:0% +instruction to merge Paytas pub key hash +and pay to script a sh so that a single + + align:start position:0% +and pay to script a sh so that a single + + + align:start position:0% +and pay to script a sh so that a single +output can do both the ID as you make a + + align:start position:0% +output can do both the ID as you make a + + + align:start position:0% +output can do both the ID as you make a +key J and J is an actual key like you + + align:start position:0% +key J and J is an actual key like you + + + align:start position:0% +key J and J is an actual key like you +have the private key for it it's a + + align:start position:0% +have the private key for it it's a + + + align:start position:0% +have the private key for it it's a +regular old pump key and you have a + + align:start position:0% +regular old pump key and you have a + + + align:start position:0% +regular old pump key and you have a +script Z and instead of sending either + + align:start position:0% +script Z and instead of sending either + + + align:start position:0% +script Z and instead of sending either +to the script Z in a pane of script hash + + align:start position:0% +to the script Z in a pane of script hash + + + align:start position:0% +to the script Z in a pane of script hash +construction or to you know hash this + + align:start position:0% +construction or to you know hash this + + + align:start position:0% +construction or to you know hash this +key J and said to the pub key ash you + + align:start position:0% +key J and said to the pub key ash you + + + align:start position:0% +key J and said to the pub key ash you +say I'm gonna compute key C which is J + + align:start position:0% +say I'm gonna compute key C which is J + + + align:start position:0% +say I'm gonna compute key C which is J +plus the hash of my script concatenated + + align:start position:0% +plus the hash of my script concatenated + + + align:start position:0% +plus the hash of my script concatenated +with J times G so this is the same as + + align:start position:0% +with J times G so this is the same as + + + align:start position:0% +with J times G so this is the same as +the thing I just did with the operator + + align:start position:0% +the thing I just did with the operator + + + align:start position:0% +the thing I just did with the operator +mannan zero bytes right and then I send + + align:start position:0% +mannan zero bytes right and then I send + + + align:start position:0% +mannan zero bytes right and then I send +money to it + + align:start position:0% +money to it + + + align:start position:0% +money to it +and then what do I do I've sent money to + + align:start position:0% +and then what do I do I've sent money to + + + align:start position:0% +and then what do I do I've sent money to +this C point can I sign with C's private + + align:start position:0% +this C point can I sign with C's private + + + align:start position:0% +this C point can I sign with C's private +key right + + align:start position:0% +key right + + + align:start position:0% +key right +I know I know little J right that's a + + align:start position:0% +I know I know little J right that's a + + + align:start position:0% +I know I know little J right that's a +regular key can do I know little C sure + + align:start position:0% +regular key can do I know little C sure + + + align:start position:0% +regular key can do I know little C sure +right yeah I know that little C is just + + align:start position:0% +right yeah I know that little C is just + + + align:start position:0% +right yeah I know that little C is just +the J private key plus this hash so if I + + align:start position:0% +the J private key plus this hash so if I + + + align:start position:0% +the J private key plus this hash so if I +want to treat it as a pay to pub key + + align:start position:0% +want to treat it as a pay to pub key + + + align:start position:0% +want to treat it as a pay to pub key +hash I just signed with little C assign + + align:start position:0% +hash I just signed with little C assign + + + align:start position:0% +hash I just signed with little C assign +my transaction and I'm good + + align:start position:0% +my transaction and I'm good + + + align:start position:0% +my transaction and I'm good +nobody has to know that I did this + + align:start position:0% +nobody has to know that I did this + + + align:start position:0% +nobody has to know that I did this +however if I want to make it into a beta + + align:start position:0% +however if I want to make it into a beta + + + align:start position:0% +however if I want to make it into a beta +script a sh I reveal the script Z and + + align:start position:0% +script a sh I reveal the script Z and + + + align:start position:0% +script a sh I reveal the script Z and +the you know sub ki J and then I put + + align:start position:0% +the you know sub ki J and then I put + + + align:start position:0% +the you know sub ki J and then I put +some arguments on and then run the + + align:start position:0% +some arguments on and then run the + + + align:start position:0% +some arguments on and then run the +script so if I don't want to show that + + align:start position:0% +script so if I don't want to show that + + + align:start position:0% +script so if I don't want to show that +there was a script I don't have to write + + align:start position:0% +there was a script I don't have to write + + + align:start position:0% +there was a script I don't have to write +it just just sign with this the private + + align:start position:0% +it just just sign with this the private + + + align:start position:0% +it just just sign with this the private +keys that nobody knows that there was a + + align:start position:0% +keys that nobody knows that there was a + + + align:start position:0% +keys that nobody knows that there was a +script at all and it may so maybe 80 + + align:start position:0% +script at all and it may so maybe 80 + + + align:start position:0% +script at all and it may so maybe 80 +maybe if everyone's using this 80% of + + align:start position:0% +maybe if everyone's using this 80% of + + + align:start position:0% +maybe if everyone's using this 80% of +the time that's what happens maybe there + + align:start position:0% +the time that's what happens maybe there + + + align:start position:0% +the time that's what happens maybe there +was a script in there maybe there wasn't + + align:start position:0% +was a script in there maybe there wasn't + + + align:start position:0% +was a script in there maybe there wasn't +can't tell right however if I want to + + align:start position:0% +can't tell right however if I want to + + + align:start position:0% +can't tell right however if I want to +reveal hey actually this time I'm using + + align:start position:0% +reveal hey actually this time I'm using + + + align:start position:0% +reveal hey actually this time I'm using +the script so I revealed J&Z everyone + + align:start position:0% +the script so I revealed J&Z everyone + + + align:start position:0% +the script so I revealed J&Z everyone +computes okay well if I add J to the + + align:start position:0% +computes okay well if I add J to the + + + align:start position:0% +computes okay well if I add J to the +hash of Z and J times G does that equal + + align:start position:0% +hash of Z and J times G does that equal + + + align:start position:0% +hash of Z and J times G does that equal +C the key that is in the output script + + align:start position:0% +C the key that is in the output script + + + align:start position:0% +C the key that is in the output script +itself and if it does cool that was a + + align:start position:0% +itself and if it does cool that was a + + + align:start position:0% +itself and if it does cool that was a +valid proof that you actually committed + + align:start position:0% +valid proof that you actually committed + + + align:start position:0% +valid proof that you actually committed +to Z and now I run the script to see any + + align:start position:0% +to Z and now I run the script to see any + + + align:start position:0% +to Z and now I run the script to see any +questions about this makes sense so it's + + align:start position:0% +questions about this makes sense so it's + + + align:start position:0% +questions about this makes sense so it's +actually pretty simple it follows + + align:start position:0% +actually pretty simple it follows + + + align:start position:0% +actually pretty simple it follows +directly from the proofs from the paid + + align:start position:0% +directly from the proofs from the paid + + + align:start position:0% +directly from the proofs from the paid +contract hash and it's really cool + + align:start position:0% +contract hash and it's really cool + + + align:start position:0% +contract hash and it's really cool +because Opie I thought it was doing + + align:start position:0% +because Opie I thought it was doing + + + align:start position:0% +because Opie I thought it was doing +anyway so what you can do is you can + + align:start position:0% +anyway so what you can do is you can + + + align:start position:0% +anyway so what you can do is you can +make the sum of everyone's keys and so + + align:start position:0% +make the sum of everyone's keys and so + + + align:start position:0% +make the sum of everyone's keys and so +in store signatures we can do this + + align:start position:0% +in store signatures we can do this + + + align:start position:0% +in store signatures we can do this +and we can sign without revealing each + + align:start position:0% +and we can sign without revealing each + + + align:start position:0% +and we can sign without revealing each +other's private keys so you can say okay + + align:start position:0% +other's private keys so you can say okay + + + align:start position:0% +other's private keys so you can say okay +in what I'm gonna do is J is the sum of + + align:start position:0% +in what I'm gonna do is J is the sum of + + + align:start position:0% +in what I'm gonna do is J is the sum of +like 50 different pub keys and then Z is + + align:start position:0% +like 50 different pub keys and then Z is + + + align:start position:0% +like 50 different pub keys and then Z is +that Merkel tree of two of 50 signatures + + align:start position:0% +that Merkel tree of two of 50 signatures + + + align:start position:0% +that Merkel tree of two of 50 signatures +so if I want to use two of 50 I have to + + align:start position:0% +so if I want to use two of 50 I have to + + + align:start position:0% +so if I want to use two of 50 I have to +reveal and then I have to do the proof + + align:start position:0% +reveal and then I have to do the proof + + + align:start position:0% +reveal and then I have to do the proof +but if I can get all 50 of 50 people to + + align:start position:0% +but if I can get all 50 of 50 people to + + + align:start position:0% +but if I can get all 50 of 50 people to +sign they can produce a signature with + + align:start position:0% +sign they can produce a signature with + + + align:start position:0% +sign they can produce a signature with +private key little C so when everyone's + + align:start position:0% +private key little C so when everyone's + + + align:start position:0% +private key little C so when everyone's +cooperating it it you don't even see + + align:start position:0% +cooperating it it you don't even see + + + align:start position:0% +cooperating it it you don't even see +that there was a script involved and you + + align:start position:0% +that there was a script involved and you + + + align:start position:0% +that there was a script involved and you +can do this with signatures you cannot + + align:start position:0% +can do this with signatures you cannot + + + align:start position:0% +can do this with signatures you cannot +do this with ECDSA so probably this + + align:start position:0% +do this with ECDSA so probably this + + + align:start position:0% +do this with ECDSA so probably this +would be you know put into Bitcoin + + align:start position:0% +would be you know put into Bitcoin + + + align:start position:0% +would be you know put into Bitcoin +alongside ashen or signature kind of + + align:start position:0% +alongside ashen or signature kind of + + + align:start position:0% +alongside ashen or signature kind of +construction and this seems useful + + align:start position:0% +construction and this seems useful + + + align:start position:0% +construction and this seems useful +because in most cases most smart + + align:start position:0% +because in most cases most smart + + + align:start position:0% +because in most cases most smart +contracts most multi say does have sort + + align:start position:0% +contracts most multi say does have sort + + + align:start position:0% +contracts most multi say does have sort +of an all participants sign clause + + align:start position:0% +of an all participants sign clause + + + align:start position:0% +of an all participants sign clause +even if we don't code it in right now + + align:start position:0% +even if we don't code it in right now + + + align:start position:0% +even if we don't code it in right now +it's generally the case like you know + + align:start position:0% +it's generally the case like you know + + + align:start position:0% +it's generally the case like you know +two of three will be saying well three + + align:start position:0% +two of three will be saying well three + + + align:start position:0% +two of three will be saying well three +of three is good and if you do three of + + align:start position:0% +of three is good and if you do three of + + + align:start position:0% +of three is good and if you do three of +three + + align:start position:0% +three + + + align:start position:0% +three +hey you don't even see that there was + + align:start position:0% +hey you don't even see that there was + + + align:start position:0% +hey you don't even see that there was +two of three and so that preserves + + align:start position:0% +two of three and so that preserves + + + align:start position:0% +two of three and so that preserves +privacy it's safe space and most of the + + align:start position:0% +privacy it's safe space and most of the + + + align:start position:0% +privacy it's safe space and most of the +time all the participants can be online + + align:start position:0% +time all the participants can be online + + + align:start position:0% +time all the participants can be online +so that's the same that's the same basic + + align:start position:0% +so that's the same that's the same basic + + + align:start position:0% +so that's the same that's the same basic +ideas and lightning if everyone's + + align:start position:0% +ideas and lightning if everyone's + + + align:start position:0% +ideas and lightning if everyone's +cooperative you don't even see that + + align:start position:0% +cooperative you don't even see that + + + align:start position:0% +cooperative you don't even see that +there was a lightning Channel right you + + align:start position:0% +there was a lightning Channel right you + + + align:start position:0% +there was a lightning Channel right you +just you know together broadcast a + + align:start position:0% +just you know together broadcast a + + + align:start position:0% +just you know together broadcast a +transaction with just two of two + + align:start position:0% +transaction with just two of two + + + align:start position:0% +transaction with just two of two +multi-state but in lightning you do see + + align:start position:0% +multi-state but in lightning you do see + + + align:start position:0% +multi-state but in lightning you do see +that there was two of two multi sakes so + + align:start position:0% +that there was two of two multi sakes so + + + align:start position:0% +that there was two of two multi sakes so +you can sort of see oh it was either a + + align:start position:0% +you can sort of see oh it was either a + + + align:start position:0% +you can sort of see oh it was either a +channel or multi-sig but in this kind of + + align:start position:0% +channel or multi-sig but in this kind of + + + align:start position:0% +channel or multi-sig but in this kind of +construction + + align:start position:0% +construction + + + align:start position:0% +construction +you wouldn't even show that you say okay + + align:start position:0% +you wouldn't even show that you say okay + + + align:start position:0% +you wouldn't even show that you say okay +this is actually two of two multi-sig + + align:start position:0% +this is actually two of two multi-sig + + + align:start position:0% +this is actually two of two multi-sig +but we can merge them Oh + + align:start position:0% +but we can merge them Oh + + + align:start position:0% +but we can merge them Oh +other weird trick you can make a public + + align:start position:0% +other weird trick you can make a public + + + align:start position:0% +other weird trick you can make a public +key and prove that there is no known + + align:start position:0% +key and prove that there is no known + + + align:start position:0% +key and prove that there is no known +private key right so what if I only want + + align:start position:0% +private key right so what if I only want + + + align:start position:0% +private key right so what if I only want +this script Z and there is no set of + + align:start position:0% +this script Z and there is no set of + + + align:start position:0% +this script Z and there is no set of +everyone signing right I don't want that + + align:start position:0% +everyone signing right I don't want that + + + align:start position:0% +everyone signing right I don't want that +to be a requirement what if I only want + + align:start position:0% +to be a requirement what if I only want + + + align:start position:0% +to be a requirement what if I only want +this script hash I can do that so + + align:start position:0% +this script hash I can do that so + + + align:start position:0% +this script hash I can do that so +interactively I can use someone else's J + + align:start position:0% +interactively I can use someone else's J + + + align:start position:0% +interactively I can use someone else's J +if I if there's + + align:start position:0% +if I if there's + + + align:start position:0% +if I if there's +you know if I'm sending into a script + + align:start position:0% +you know if I'm sending into a script + + + align:start position:0% +you know if I'm sending into a script +that involves someone else they say hey + + align:start position:0% +that involves someone else they say hey + + + align:start position:0% +that involves someone else they say hey +can you come up with a key J I'm going + + align:start position:0% +can you come up with a key J I'm going + + + align:start position:0% +can you come up with a key J I'm going +to compute a key see that's J plus the + + align:start position:0% +to compute a key see that's J plus the + + + align:start position:0% +to compute a key see that's J plus the +hash of the script comma J times G and + + align:start position:0% +hash of the script comma J times G and + + + align:start position:0% +hash of the script comma J times G and +then I can prove that to you after the + + align:start position:0% +then I can prove that to you after the + + + align:start position:0% +then I can prove that to you after the +fact and you can say okay well I know + + align:start position:0% +fact and you can say okay well I know + + + align:start position:0% +fact and you can say okay well I know +it's my key so interactive I can show + + align:start position:0% +it's my key so interactive I can show + + + align:start position:0% +it's my key so interactive I can show +that it's someone else's key + + align:start position:0% +that it's someone else's key + + + align:start position:0% +that it's someone else's key +non-interactive I can just say look I + + align:start position:0% +non-interactive I can just say look I + + + align:start position:0% +non-interactive I can just say look I +know the preimage of the x-coordinate of + + align:start position:0% +know the preimage of the x-coordinate of + + + align:start position:0% +know the preimage of the x-coordinate of +J so basically I know I can prove to you + + align:start position:0% +J so basically I know I can prove to you + + + align:start position:0% +J so basically I know I can prove to you +that like there's no way I came up with + + align:start position:0% +that like there's no way I came up with + + + align:start position:0% +that like there's no way I came up with +this point on the curve in the normal + + align:start position:0% +this point on the curve in the normal + + + align:start position:0% +this point on the curve in the normal +like multiplied by G way right because + + align:start position:0% +like multiplied by G way right because + + + align:start position:0% +like multiplied by G way right because +if I know you know that sort of shows + + align:start position:0% +if I know you know that sort of shows + + + align:start position:0% +if I know you know that sort of shows +that I came up with the x-coordinate by + + align:start position:0% +that I came up with the x-coordinate by + + + align:start position:0% +that I came up with the x-coordinate by +just hashing a random number or non + + align:start position:0% +just hashing a random number or non + + + align:start position:0% +just hashing a random number or non +random number if it's the hash of zero + + align:start position:0% +random number if it's the hash of zero + + + align:start position:0% +random number if it's the hash of zero +or if the hash of you know some some + + align:start position:0% +or if the hash of you know some some + + + align:start position:0% +or if the hash of you know some some +anything the idea is I randomly picked + + align:start position:0% +anything the idea is I randomly picked + + + align:start position:0% +anything the idea is I randomly picked +an x-coordinate on this curve figured + + align:start position:0% +an x-coordinate on this curve figured + + + align:start position:0% +an x-coordinate on this curve figured +out what the y-coordinate was turn that + + align:start position:0% +out what the y-coordinate was turn that + + + align:start position:0% +out what the y-coordinate was turn that +into a point and then used it in this + + align:start position:0% +into a point and then used it in this + + + align:start position:0% +into a point and then used it in this +construction if I do that you can be + + align:start position:0% +construction if I do that you can be + + + align:start position:0% +construction if I do that you can be +pretty sure that I don't know the + + align:start position:0% +pretty sure that I don't know the + + + align:start position:0% +pretty sure that I don't know the +private key for J because I didn't + + align:start position:0% +private key for J because I didn't + + + align:start position:0% +private key for J because I didn't +compute it the right way does that make + + align:start position:0% +compute it the right way does that make + + + align:start position:0% +compute it the right way does that make +sense yeah so you can do that that's a + + align:start position:0% +sense yeah so you can do that that's a + + + align:start position:0% +sense yeah so you can do that that's a +way to then prove to other people like + + align:start position:0% +way to then prove to other people like + + + align:start position:0% +way to then prove to other people like +there is no J right it's a point on the + + align:start position:0% +there is no J right it's a point on the + + + align:start position:0% +there is no J right it's a point on the +curve but it's a random point on the + + align:start position:0% +curve but it's a random point on the + + + align:start position:0% +curve but it's a random point on the +curve so there's no way I can sign with + + align:start position:0% +curve so there's no way I can sign with + + + align:start position:0% +curve so there's no way I can sign with +C right the only way that this is gonna + + align:start position:0% +C right the only way that this is gonna + + + align:start position:0% +C right the only way that this is gonna +that this you know I sent a pub key C + + align:start position:0% +that this you know I sent a pub key C + + + align:start position:0% +that this you know I sent a pub key C +and I prove to you look C is not a key + + align:start position:0% +and I prove to you look C is not a key + + + align:start position:0% +and I prove to you look C is not a key +that anyone can sign with however there + + align:start position:0% +that anyone can sign with however there + + + align:start position:0% +that anyone can sign with however there +is a point J and there's a script Z and + + align:start position:0% +is a point J and there's a script Z and + + + align:start position:0% +is a point J and there's a script Z and +you can execute the script so that's + + align:start position:0% +you can execute the script so that's + + + align:start position:0% +you can execute the script so that's +that's useful in many cases where you + + align:start position:0% +that's useful in many cases where you + + + align:start position:0% +that's useful in many cases where you +want to prove to people that look there + + align:start position:0% +want to prove to people that look there + + + align:start position:0% +want to prove to people that look there +is no key here it's just a script and + + align:start position:0% +is no key here it's just a script and + + + align:start position:0% +is no key here it's just a script and +then you you know everyone will find out + + align:start position:0% +then you you know everyone will find out + + + align:start position:0% +then you you know everyone will find out +later when you spend it but they don't + + align:start position:0% +later when you spend it but they don't + + + align:start position:0% +later when you spend it but they don't +have to know that there was no key they + + align:start position:0% +have to know that there was no key they + + + align:start position:0% +have to know that there was no key they +just know that the script got executed + + align:start position:0% +just know that the script got executed + + + align:start position:0% +just know that the script got executed +so that that's a nice sort of hatch + + align:start position:0% +so that that's a nice sort of hatch + + + align:start position:0% +so that that's a nice sort of hatch +where you can you know default if + + align:start position:0% +where you can you know default if + + + align:start position:0% +where you can you know default if +there's any use cases where in the + + align:start position:0% +there's any use cases where in the + + + align:start position:0% +there's any use cases where in the +current script hash you want that exact + + align:start position:0% +current script hash you want that exact + + + align:start position:0% +current script hash you want that exact +same functionality and you don't want + + align:start position:0% +same functionality and you don't want + + + align:start position:0% +same functionality and you don't want +this new functionality you can sort of + + align:start position:0% +this new functionality you can sort of + + + align:start position:0% +this new functionality you can sort of +get rid of it this way + + align:start position:0% + + + + align:start position:0% + +okay the idea however is that we were + + align:start position:0% +okay the idea however is that we were + + + align:start position:0% +okay the idea however is that we were +trying to make your special transaction + + align:start position:0% +trying to make your special transaction + + + align:start position:0% +trying to make your special transaction +scripts not stand out but it's more that + + align:start position:0% +scripts not stand out but it's more that + + + align:start position:0% +scripts not stand out but it's more that +you can say let's say I have my wallet + + align:start position:0% +you can say let's say I have my wallet + + + align:start position:0% +you can say let's say I have my wallet +software and it always uses p2w sa fee - + + align:start position:0% +software and it always uses p2w sa fee - + + + align:start position:0% +software and it always uses p2w sa fee - +SH or something then I can say oh I bet + + align:start position:0% +SH or something then I can say oh I bet + + + align:start position:0% +SH or something then I can say oh I bet +this is the same person I can try to + + align:start position:0% +this is the same person I can try to + + + align:start position:0% +this is the same person I can try to +track who's spending yeah probably a big + + align:start position:0% +track who's spending yeah probably a big + + + align:start position:0% +track who's spending yeah probably a big +part of it is privacy maybe they're you + + align:start position:0% +part of it is privacy maybe they're you + + + align:start position:0% +part of it is privacy maybe they're you +know discriminate against that Emma's + + align:start position:0% +know discriminate against that Emma's + + + align:start position:0% +know discriminate against that Emma's +like minors probably the minors don't + + align:start position:0% +like minors probably the minors don't + + + align:start position:0% +like minors probably the minors don't +care but it's more like if if everyone's + + align:start position:0% +care but it's more like if if everyone's + + + align:start position:0% +care but it's more like if if everyone's +using software that could create similar + + align:start position:0% +using software that could create similar + + + align:start position:0% +using software that could create similar +transactions then it becomes much harder + + align:start position:0% +transactions then it becomes much harder + + + align:start position:0% +transactions then it becomes much harder +to tell people apart and it has more + + align:start position:0% +to tell people apart and it has more + + + align:start position:0% +to tell people apart and it has more +privacy for the transactions they need + + align:start position:0% +privacy for the transactions they need + + + align:start position:0% +privacy for the transactions they need +to know they need to know the script and + + align:start position:0% +to know they need to know the script and + + + align:start position:0% +to know they need to know the script and +J which is not obvious from see right if + + align:start position:0% +J which is not obvious from see right if + + + align:start position:0% +J which is not obvious from see right if +you jetan c is the only thing you see on + + align:start position:0% +you jetan c is the only thing you see on + + + align:start position:0% +you jetan c is the only thing you see on +the blockchain in the output and so they + + align:start position:0% +the blockchain in the output and so they + + + align:start position:0% +the blockchain in the output and so they +just say it's a key + + align:start position:0% +just say it's a key + + + align:start position:0% +just say it's a key +probably someone knows the private key + + align:start position:0% +probably someone knows the private key + + + align:start position:0% +probably someone knows the private key +maybe there's some weird thing like this + + align:start position:0% +maybe there's some weird thing like this + + + align:start position:0% +maybe there's some weird thing like this +going on you don't have to use this + + align:start position:0% +going on you don't have to use this + + + align:start position:0% +going on you don't have to use this +right and then yeah so they won't know + + align:start position:0% +right and then yeah so they won't know + + + align:start position:0% +right and then yeah so they won't know +what J or Z are yeah yeah you can + + align:start position:0% +what J or Z are yeah yeah you can + + + align:start position:0% +what J or Z are yeah yeah you can +publish it you can publically publish it + + align:start position:0% +publish it you can publically publish it + + + align:start position:0% +publish it you can publically publish it +if you want and tell everyone in the + + align:start position:0% +if you want and tell everyone in the + + + align:start position:0% +if you want and tell everyone in the +world hey this C is actually this J Plus + + align:start position:0% +world hey this C is actually this J Plus + + + align:start position:0% +world hey this C is actually this J Plus +this script Z they still can't spend it + + align:start position:0% +this script Z they still can't spend it + + + align:start position:0% +this script Z they still can't spend it +right that's all that can be public even + + align:start position:0% +right that's all that can be public even + + + align:start position:0% +right that's all that can be public even +beforehand and then they can see oh + + align:start position:0% +beforehand and then they can see oh + + + align:start position:0% +beforehand and then they can see oh +there's a script and a key and you can + + align:start position:0% +there's a script and a key and you can + + + align:start position:0% +there's a script and a key and you can +also say sign something and prove that + + align:start position:0% +also say sign something and prove that + + + align:start position:0% +also say sign something and prove that +you know the private key for J so you + + align:start position:0% +you know the private key for J so you + + + align:start position:0% +you know the private key for J so you +can say I'm not you know I can prove + + align:start position:0% +can say I'm not you know I can prove + + + align:start position:0% +can say I'm not you know I can prove +that I'm not doing this + + align:start position:0% +that I'm not doing this + + + align:start position:0% +that I'm not doing this +there is no J kind of thing so you can + + align:start position:0% +there is no J kind of thing so you can + + + align:start position:0% +there is no J kind of thing so you can +prove all those things but you don't + + align:start position:0% +prove all those things but you don't + + + align:start position:0% +prove all those things but you don't +need to write if you for normal usage + + align:start position:0% +need to write if you for normal usage + + + align:start position:0% +need to write if you for normal usage +you just send a key C spend from key C + + align:start position:0% +you just send a key C spend from key C + + + align:start position:0% +you just send a key C spend from key C +you're done and if you want to + + align:start position:0% +you're done and if you want to + + + align:start position:0% +you're done and if you want to +to spend from the script to Z you just + + align:start position:0% +to spend from the script to Z you just + + + align:start position:0% +to spend from the script to Z you just +provide J the script Z and then execute + + align:start position:0% +provide J the script Z and then execute + + + align:start position:0% +provide J the script Z and then execute +the script so it's nice and that even + + align:start position:0% +the script so it's nice and that even + + + align:start position:0% +the script so it's nice and that even +you might have had a script and then you + + align:start position:0% +you might have had a script and then you + + + align:start position:0% +you might have had a script and then you +didn't use it so you didn't reveal that + + align:start position:0% +didn't use it so you didn't reveal that + + + align:start position:0% +didn't use it so you didn't reveal that +there was a script so it helps with + + align:start position:0% +there was a script so it helps with + + + align:start position:0% +there was a script so it helps with +privacy it helps with efficiency in many + + align:start position:0% +privacy it helps with efficiency in many + + + align:start position:0% +privacy it helps with efficiency in many +cases because if you don't need to use + + align:start position:0% +cases because if you don't need to use + + + align:start position:0% +cases because if you don't need to use +the script you don't have to so in a lot + + align:start position:0% +the script you don't have to so in a lot + + + align:start position:0% +the script you don't have to so in a lot +of cases you say all you know everyone's + + align:start position:0% +of cases you say all you know everyone's + + + align:start position:0% +of cases you say all you know everyone's +all three of the two of three multi + + align:start position:0% +all three of the two of three multi + + + align:start position:0% +all three of the two of three multi +SIG's are on board so let's you see + + align:start position:0% +SIG's are on board so let's you see + + + align:start position:0% +SIG's are on board so let's you see +instead of the script Z so it's pretty + + align:start position:0% +instead of the script Z so it's pretty + + + align:start position:0% +instead of the script Z so it's pretty +cool okay so questions about this go + + align:start position:0% +cool okay so questions about this go + + + align:start position:0% +cool okay so questions about this go +into the next crazy thing okay so yeah a + + align:start position:0% +into the next crazy thing okay so yeah a + + + align:start position:0% +into the next crazy thing okay so yeah a +little notes about taproot anyone can + + align:start position:0% +little notes about taproot anyone can + + + align:start position:0% +little notes about taproot anyone can +make a key and script and send to it + + align:start position:0% +make a key and script and send to it + + + align:start position:0% +make a key and script and send to it +only the pub keys are needed right so if + + align:start position:0% +only the pub keys are needed right so if + + + align:start position:0% +only the pub keys are needed right so if +I want to send to something that's you + + align:start position:0% +I want to send to something that's you + + + align:start position:0% +I want to send to something that's you +know three of three Alice Bob and Carol + + align:start position:0% +know three of three Alice Bob and Carol + + + align:start position:0% +know three of three Alice Bob and Carol +add it all together or two of the three + + align:start position:0% +add it all together or two of the three + + + align:start position:0% +add it all together or two of the three +of Alice and Bob and Carol I don't have + + align:start position:0% +of Alice and Bob and Carol I don't have + + + align:start position:0% +of Alice and Bob and Carol I don't have +to even ask Alice Bob and Carol if I + + align:start position:0% +to even ask Alice Bob and Carol if I + + + align:start position:0% +to even ask Alice Bob and Carol if I +know their public keys I can just + + align:start position:0% +know their public keys I can just + + + align:start position:0% +know their public keys I can just +compute all this myself and send the + + align:start position:0% +compute all this myself and send the + + + align:start position:0% +compute all this myself and send the +send money to their send that one right + + align:start position:0% +send money to their send that one right + + + align:start position:0% +send money to their send that one right +and I can compute any construction I + + align:start position:0% +and I can compute any construction I + + + align:start position:0% +and I can compute any construction I +want I can make it one of three right I + + align:start position:0% +want I can make it one of three right I + + + align:start position:0% +want I can make it one of three right I +know that there's Alice BA I know Alice + + align:start position:0% +know that there's Alice BA I know Alice + + + align:start position:0% +know that there's Alice BA I know Alice +Bob and Carols public keys and I can say + + align:start position:0% +Bob and Carols public keys and I can say + + + align:start position:0% +Bob and Carols public keys and I can say +hey Alice Bob and Carol I'm giving you + + align:start position:0% +hey Alice Bob and Carol I'm giving you + + + align:start position:0% +hey Alice Bob and Carol I'm giving you +all money and you can fight over it or + + align:start position:0% +all money and you can fight over it or + + + align:start position:0% +all money and you can fight over it or +you can cooperate like it's you know any + + align:start position:0% +you can cooperate like it's you know any + + + align:start position:0% +you can cooperate like it's you know any +of you get it and so the idea is one of + + align:start position:0% +of you get it and so the idea is one of + + + align:start position:0% +of you get it and so the idea is one of +three multi-sig script goes into here + + align:start position:0% +three multi-sig script goes into here + + + align:start position:0% +three multi-sig script goes into here +and then three of three is here so if + + align:start position:0% +and then three of three is here so if + + + align:start position:0% +and then three of three is here so if +you cooperate you save a little bit of + + align:start position:0% +you cooperate you save a little bit of + + + align:start position:0% +you cooperate you save a little bit of +space on them and the fees are smaller + + align:start position:0% +space on them and the fees are smaller + + + align:start position:0% +space on them and the fees are smaller +but if you don't cooperate any of you + + align:start position:0% +but if you don't cooperate any of you + + + align:start position:0% +but if you don't cooperate any of you +can grab it immediately I don't know how + + align:start position:0% +can grab it immediately I don't know how + + + align:start position:0% +can grab it immediately I don't know how +useful that is but you could do this + + align:start position:0% +useful that is but you could do this + + + align:start position:0% +useful that is but you could do this +right you you don't need knowledge of + + align:start position:0% +right you you don't need knowledge of + + + align:start position:0% +right you you don't need knowledge of +any private keys to construct see only + + align:start position:0% +any private keys to construct see only + + + align:start position:0% +any private keys to construct see only +the pub keys are needed that's actually + + align:start position:0% +the pub keys are needed that's actually + + + align:start position:0% +the pub keys are needed that's actually +really nice because you're creating so + + align:start position:0% +really nice because you're creating so + + + align:start position:0% +really nice because you're creating so +that's that's the same is currently the + + align:start position:0% +that's that's the same is currently the + + + align:start position:0% +that's that's the same is currently the +case in Bitcoin right if you're creating + + align:start position:0% +case in Bitcoin right if you're creating + + + align:start position:0% +case in Bitcoin right if you're creating +an output script like paid a pub key + + align:start position:0% +an output script like paid a pub key + + + align:start position:0% +an output script like paid a pub key +hash paid a script hash there's no + + align:start position:0% +hash paid a script hash there's no + + + align:start position:0% +hash paid a script hash there's no +private keys involved in that process + + align:start position:0% +private keys involved in that process + + + align:start position:0% +private keys involved in that process +right you just tell everyone okay which + + align:start position:0% +right you just tell everyone okay which + + + align:start position:0% +right you just tell everyone okay which +differs and is the important distinction + + align:start position:0% +differs and is the important distinction + + + align:start position:0% +differs and is the important distinction +between the next school thing + + align:start position:0% +between the next school thing + + + align:start position:0% +between the next school thing +which is craft route also Greg Maxwell + + align:start position:0% +which is craft route also Greg Maxwell + + + align:start position:0% +which is craft route also Greg Maxwell +like a week or two after taproot they're + + align:start position:0% +like a week or two after taproot they're + + + align:start position:0% +like a week or two after taproot they're +not actually that similar but it was + + align:start position:0% +not actually that similar but it was + + + align:start position:0% +not actually that similar but it was +like wait you know people are sort of + + align:start position:0% +like wait you know people are sort of + + + align:start position:0% +like wait you know people are sort of +talking about it so the idea is allow a + + align:start position:0% +talking about it so the idea is allow a + + + align:start position:0% +talking about it so the idea is allow a +lot of scripts with a proof that goes up + + align:start position:0% +lot of scripts with a proof that goes up + + + align:start position:0% +lot of scripts with a proof that goes up +in size with of one okay it doesn't go + + align:start position:0% +in size with of one okay it doesn't go + + + align:start position:0% +in size with of one okay it doesn't go +up in size so the Merkel proofs right + + align:start position:0% +up in size so the Merkel proofs right + + + align:start position:0% +up in size so the Merkel proofs right +mast grow in log n so if you've got a + + align:start position:0% +mast grow in log n so if you've got a + + + align:start position:0% +mast grow in log n so if you've got a +million different scripts you're gonna + + align:start position:0% +million different scripts you're gonna + + + align:start position:0% +million different scripts you're gonna +take twenty something like twenty hashes + + align:start position:0% +take twenty something like twenty hashes + + + align:start position:0% +take twenty something like twenty hashes +or whatever to prove that what's a proof + + align:start position:0% +or whatever to prove that what's a proof + + + align:start position:0% +or whatever to prove that what's a proof +that go grows in of one of the number of + + align:start position:0% +that go grows in of one of the number of + + + align:start position:0% +that go grows in of one of the number of +things being proven it's actually not + + align:start position:0% +things being proven it's actually not + + + align:start position:0% +things being proven it's actually not +it's kind of obvious like I want to + + align:start position:0% +it's kind of obvious like I want to + + + align:start position:0% +it's kind of obvious like I want to +prove I want to prove something + + align:start position:0% +prove I want to prove something + + + align:start position:0% +prove I want to prove something +and the proof size does not change + + align:start position:0% +and the proof size does not change + + + align:start position:0% +and the proof size does not change +regardless of how many things + + align:start position:0% +regardless of how many things + + + align:start position:0% +regardless of how many things +I'm proving well it's just a signature + + align:start position:0% +I'm proving well it's just a signature + + + align:start position:0% +I'm proving well it's just a signature +right if I make a million signatures + + align:start position:0% +right if I make a million signatures + + + align:start position:0% +right if I make a million signatures +they're all the same size so I could + + align:start position:0% +they're all the same size so I could + + + align:start position:0% +they're all the same size so I could +instead of making a Merkel root I just + + align:start position:0% +instead of making a Merkel root I just + + + align:start position:0% +instead of making a Merkel root I just +have all these little leaves and I just + + align:start position:0% +have all these little leaves and I just + + + align:start position:0% +have all these little leaves and I just +sign them all and a leaf with a + + align:start position:0% +sign them all and a leaf with a + + + align:start position:0% +sign them all and a leaf with a +signature it's just as good okay so the + + align:start position:0% +signature it's just as good okay so the + + + align:start position:0% +signature it's just as good okay so the +idea is this is called graft root it's + + align:start position:0% +idea is this is called graft root it's + + + align:start position:0% +idea is this is called graft root it's +similar to trap fruit in that it's got + + align:start position:0% +similar to trap fruit in that it's got + + + align:start position:0% +similar to trap fruit in that it's got +sort of two execution paths you send to + + align:start position:0% +sort of two execution paths you send to + + + align:start position:0% +sort of two execution paths you send to +a key see and there's two ways to spend + + align:start position:0% +a key see and there's two ways to spend + + + align:start position:0% +a key see and there's two ways to spend +from it so you can use the regular pay + + align:start position:0% +from it so you can use the regular pay + + + align:start position:0% +from it so you can use the regular pay +to pub key hash mode where you're just + + align:start position:0% +to pub key hash mode where you're just + + + align:start position:0% +to pub key hash mode where you're just +spending from C you just sign with key C + + align:start position:0% +spending from C you just sign with key C + + + align:start position:0% +spending from C you just sign with key C +your transaction same as in tap root + + align:start position:0% +your transaction same as in tap root + + + align:start position:0% +your transaction same as in tap root +same as in regular Bitcoin right now + + align:start position:0% +same as in regular Bitcoin right now + + + align:start position:0% +same as in regular Bitcoin right now +that's the easy one the script version + + align:start position:0% +that's the easy one the script version + + + align:start position:0% +that's the easy one the script version +is I show a script s and a signature + + align:start position:0% +is I show a script s and a signature + + + align:start position:0% +is I show a script s and a signature +from key C on the message s and then I + + align:start position:0% +from key C on the message s and then I + + + align:start position:0% +from key C on the message s and then I +execute that script so this is kind of + + align:start position:0% +execute that script so this is kind of + + + align:start position:0% +execute that script so this is kind of +cool right you say look I'm sending you + + align:start position:0% +cool right you say look I'm sending you + + + align:start position:0% +cool right you say look I'm sending you +a key and either that key itself signs + + align:start position:0% +a key and either that key itself signs + + + align:start position:0% +a key and either that key itself signs +or that key endorses a script to the to + + align:start position:0% +or that key endorses a script to the to + + + align:start position:0% +or that key endorses a script to the to +be executed and I can make as many of + + align:start position:0% +be executed and I can make as many of + + + align:start position:0% +be executed and I can make as many of +these as I want right so if I want a + + align:start position:0% +these as I want right so if I want a + + + align:start position:0% +these as I want right so if I want a +thousand different scripts it's not like + + align:start position:0% +thousand different scripts it's not like + + + align:start position:0% +thousand different scripts it's not like +I have to prove + + align:start position:0% +I have to prove + + + align:start position:0% +I have to prove +inclusion in three that's gonna be + + align:start position:0% +inclusion in three that's gonna be + + + align:start position:0% +inclusion in three that's gonna be +height 22 or height 12 or whatever I + + align:start position:0% +height 22 or height 12 or whatever I + + + align:start position:0% +height 22 or height 12 or whatever I +just have a signature saying okay kisi + + align:start position:0% +just have a signature saying okay kisi + + + align:start position:0% +just have a signature saying okay kisi +signed this to of fifty multi-sig kisi + + align:start position:0% +signed this to of fifty multi-sig kisi + + + align:start position:0% +signed this to of fifty multi-sig kisi +also signed this three of 52 of two + + align:start position:0% +also signed this three of 52 of two + + + align:start position:0% +also signed this three of 52 of two +other two of fifty multi Singh so the + + align:start position:0% +other two of fifty multi Singh so the + + + align:start position:0% +other two of fifty multi Singh so the +one that I'm actually using I just + + align:start position:0% +one that I'm actually using I just + + + align:start position:0% +one that I'm actually using I just +provide the proof that it's you know the + + align:start position:0% +provide the proof that it's you know the + + + align:start position:0% +provide the proof that it's you know the +proof of inclusion is just a signature + + align:start position:0% +proof of inclusion is just a signature + + + align:start position:0% +proof of inclusion is just a signature +questions about this makes sense kind of + + align:start position:0% +questions about this makes sense kind of + + + align:start position:0% +questions about this makes sense kind of +weird it works + + align:start position:0% +weird it works + + + align:start position:0% +weird it works +the problem is did I even well that's + + align:start position:0% +the problem is did I even well that's + + + align:start position:0% +the problem is did I even well that's +the real problem is there is this kisi + + align:start position:0% +the real problem is there is this kisi + + + align:start position:0% +the real problem is there is this kisi +right so there's this sort of root key + + align:start position:0% +right so there's this sort of root key + + + align:start position:0% +right so there's this sort of root key +that controls the whole thing right + + align:start position:0% +that controls the whole thing right + + + align:start position:0% +that controls the whole thing right +implicit like the idea is kisi can all + + align:start position:0% +implicit like the idea is kisi can all + + + align:start position:0% +implicit like the idea is kisi can all +you know endorses all the different + + align:start position:0% +you know endorses all the different + + + align:start position:0% +you know endorses all the different +leaves so then in the case of mast + + align:start position:0% +leaves so then in the case of mast + + + align:start position:0% +leaves so then in the case of mast +you've got let's say four different + + align:start position:0% +you've got let's say four different + + + align:start position:0% +you've got let's say four different +scripts that can execute all four of + + align:start position:0% +scripts that can execute all four of + + + align:start position:0% +scripts that can execute all four of +those are committed to by the Merkle + + align:start position:0% +those are committed to by the Merkle + + + align:start position:0% +those are committed to by the Merkle +root in the case of graft root let's say + + align:start position:0% +root in the case of graft root let's say + + + align:start position:0% +root in the case of graft root let's say +you have four different scripts see + + align:start position:0% +you have four different scripts see + + + align:start position:0% +you have four different scripts see +signs all four of those different + + align:start position:0% +signs all four of those different + + + align:start position:0% +signs all four of those different +scripts the thing is seek ensign 10 + + align:start position:0% +scripts the thing is seek ensign 10 + + + align:start position:0% +scripts the thing is seek ensign 10 +scripts sees got total control over this + + align:start position:0% +scripts sees got total control over this + + + align:start position:0% +scripts sees got total control over this +output whereas before in the Merc the + + align:start position:0% +output whereas before in the Merc the + + + align:start position:0% +output whereas before in the Merc the +mast idea it can be different people + + align:start position:0% +mast idea it can be different people + + + align:start position:0% +mast idea it can be different people +right it could be Alison Bob Carol and + + align:start position:0% +right it could be Alison Bob Carol and + + + align:start position:0% +right it could be Alison Bob Carol and +Dave Edna and Gertrude I don't know and + + align:start position:0% +Dave Edna and Gertrude I don't know and + + + align:start position:0% +Dave Edna and Gertrude I don't know and +they might not be friends none no single + + align:start position:0% +they might not be friends none no single + + + align:start position:0% +they might not be friends none no single +entity there has full control so the + + align:start position:0% +entity there has full control so the + + + align:start position:0% +entity there has full control so the +idea of of this is well you can combine + + align:start position:0% +idea of of this is well you can combine + + + align:start position:0% +idea of of this is well you can combine +a whole bunch of people the key C is + + align:start position:0% +a whole bunch of people the key C is + + + align:start position:0% +a whole bunch of people the key C is +essentially everyone and they all have + + align:start position:0% +essentially everyone and they all have + + + align:start position:0% +essentially everyone and they all have +to sign off on all the different scripts + + align:start position:0% +to sign off on all the different scripts + + + align:start position:0% +to sign off on all the different scripts +that could happen and then distribute + + align:start position:0% +that could happen and then distribute + + + align:start position:0% +that could happen and then distribute +those signatures on those scripts which + + align:start position:0% +those signatures on those scripts which + + + align:start position:0% +those signatures on those scripts which +are groups so okay any basic idea makes + + align:start position:0% +are groups so okay any basic idea makes + + + align:start position:0% +are groups so okay any basic idea makes +sense this one's a little weirder I + + align:start position:0% +sense this one's a little weirder I + + + align:start position:0% +sense this one's a little weirder I +think I don't know if there's also a way + + align:start position:0% +think I don't know if there's also a way + + + align:start position:0% +think I don't know if there's also a way +in this so in this one there's a way to + + align:start position:0% +in this so in this one there's a way to + + + align:start position:0% +in this so in this one there's a way to +prove that there is no key C so let's + + align:start position:0% +prove that there is no key C so let's + + + align:start position:0% +prove that there is no key C so let's +sort of say look it's only gonna be this + + align:start position:0% +sort of say look it's only gonna be this + + + align:start position:0% +sort of say look it's only gonna be this +script and no one's gonna sign in the + + align:start position:0% +script and no one's gonna sign in the + + + align:start position:0% +script and no one's gonna sign in the +normal just the key signs + + align:start position:0% +normal just the key signs + + + align:start position:0% +normal just the key signs +that there's also a way to do that here + + align:start position:0% +that there's also a way to do that here + + + align:start position:0% +that there's also a way to do that here +it's much less useful though because + + align:start position:0% +it's much less useful though because + + + align:start position:0% +it's much less useful though because +what you essentially do is you you start + + align:start position:0% +what you essentially do is you you start + + + align:start position:0% +what you essentially do is you you start +with your script and then you compute a + + align:start position:0% +with your script and then you compute a + + + align:start position:0% +with your script and then you compute a +signature on it + + align:start position:0% +signature on it + + + align:start position:0% +signature on it +but you also prove that there was no + + align:start position:0% +but you also prove that there was no + + + align:start position:0% +but you also prove that there was no +private key that made the signature you + + align:start position:0% +private key that made the signature you + + + align:start position:0% +private key that made the signature you +have time it's actually really fun what + + align:start position:0% +have time it's actually really fun what + + + align:start position:0% +have time it's actually really fun what +you do is so normally you say like okay + + align:start position:0% +you do is so normally you say like okay + + + align:start position:0% +you do is so normally you say like okay +s equals K minus the hash of my message + + align:start position:0% +s equals K minus the hash of my message + + + align:start position:0% +s equals K minus the hash of my message +and R times 0.8 what if I want to prove + + align:start position:0% +and R times 0.8 what if I want to prove + + + align:start position:0% +and R times 0.8 what if I want to prove +to you that there is no a G equals R + + align:start position:0% +to you that there is no a G equals R + + + align:start position:0% +to you that there is no a G equals R +minus the hash of message oh hey I want + + align:start position:0% +minus the hash of message oh hey I want + + + align:start position:0% +minus the hash of message oh hey I want +to prove that like I do not know that + + align:start position:0% +to prove that like I do not know that + + + align:start position:0% +to prove that like I do not know that +private key and nobody knows it so what + + align:start position:0% +private key and nobody knows it so what + + + align:start position:0% +private key and nobody knows it so what +I do is I actually have to do it both I + + align:start position:0% +I do is I actually have to do it both I + + + align:start position:0% +I do is I actually have to do it both I +say okay I know the preimage of the + + align:start position:0% +say okay I know the preimage of the + + + align:start position:0% +say okay I know the preimage of the +x-coordinate same with our wait can I do + + align:start position:0% +x-coordinate same with our wait can I do + + + align:start position:0% +x-coordinate same with our wait can I do +this + + align:start position:0% +this + + + align:start position:0% +this +anyway well basically what I do is I + + align:start position:0% +anyway well basically what I do is I + + + align:start position:0% +anyway well basically what I do is I +compute a public key randomly or no I I + + align:start position:0% +compute a public key randomly or no I I + + + align:start position:0% +compute a public key randomly or no I I +first get the message I want to sign I + + align:start position:0% +first get the message I want to sign I + + + align:start position:0% +first get the message I want to sign I +make a random R yeah yeah I make a + + align:start position:0% +make a random R yeah yeah I make a + + + align:start position:0% +make a random R yeah yeah I make a +random R and I show that it's random + + align:start position:0% +random R and I show that it's random + + + align:start position:0% +random R and I show that it's random +right I know the preimage of its + + align:start position:0% +right I know the preimage of its + + + align:start position:0% +right I know the preimage of its +coordinates or something I can prove + + align:start position:0% +coordinates or something I can prove + + + align:start position:0% +coordinates or something I can prove +that I didn't construct this I don't + + align:start position:0% +that I didn't construct this I don't + + + align:start position:0% +that I didn't construct this I don't +know the private key and then I solve + + align:start position:0% +know the private key and then I solve + + + align:start position:0% +know the private key and then I solve +for a and s essentially so I can show + + align:start position:0% +for a and s essentially so I can show + + + align:start position:0% +for a and s essentially so I can show +look I've got a signature but I can + + align:start position:0% +look I've got a signature but I can + + + align:start position:0% +look I've got a signature but I can +prove that no one signed right because I + + align:start position:0% +prove that no one signed right because I + + + align:start position:0% +prove that no one signed right because I +came up with the I think I'd make a + + align:start position:0% +came up with the I think I'd make a + + + align:start position:0% +came up with the I think I'd make a +random ass and then I solve for a I + + align:start position:0% +random ass and then I solve for a I + + + align:start position:0% +random ass and then I solve for a I +solve for big a you know make a random s + + align:start position:0% +solve for big a you know make a random s + + + align:start position:0% +solve for big a you know make a random s +multiply it by G solve for it right so a + + align:start position:0% +multiply it by G solve for it right so a + + + align:start position:0% +multiply it by G solve for it right so a +divided by hash of our weight I can't do + + align:start position:0% +divided by hash of our weight I can't do + + + align:start position:0% +divided by hash of our weight I can't do +that can i yeah I can this is good + + align:start position:0% +that can i yeah I can this is good + + + align:start position:0% +that can i yeah I can this is good +equals + + align:start position:0% + + + + align:start position:0% + +I know it's equals R - s G alright so I + + align:start position:0% +I know it's equals R - s G alright so I + + + align:start position:0% +I know it's equals R - s G alright so I +come up with a random R put it in here + + align:start position:0% +come up with a random R put it in here + + + align:start position:0% +come up with a random R put it in here +come up with a message I want to sign + + align:start position:0% +come up with a message I want to sign + + + align:start position:0% +come up with a message I want to sign +and then solve for a so I can do that + + align:start position:0% +and then solve for a so I can do that + + + align:start position:0% +and then solve for a so I can do that +and I can prove that there was you know + + align:start position:0% +and I can prove that there was you know + + + align:start position:0% +and I can prove that there was you know +I can prove that there was no real a + + align:start position:0% +I can prove that there was no real a + + + align:start position:0% +I can prove that there was no real a +because of the way I constructed it like + + align:start position:0% +because of the way I constructed it like + + + align:start position:0% +because of the way I constructed it like +I know weird things about RNA and so I + + align:start position:0% +I know weird things about RNA and so I + + + align:start position:0% +I know weird things about RNA and so I +can show that this is not a real + + align:start position:0% +can show that this is not a real + + + align:start position:0% +can show that this is not a real +signature however in this case it's not + + align:start position:0% +signature however in this case it's not + + + align:start position:0% +signature however in this case it's not +that useful in the case of taproot it's + + align:start position:0% +that useful in the case of taproot it's + + + align:start position:0% +that useful in the case of taproot it's +useful because I might want to prove to + + align:start position:0% +useful because I might want to prove to + + + align:start position:0% +useful because I might want to prove to +people look this is just a script there + + align:start position:0% +people look this is just a script there + + + align:start position:0% +people look this is just a script there +is no key in this case I can still do + + align:start position:0% +is no key in this case I can still do + + + align:start position:0% +is no key in this case I can still do +that I can say there's just a script + + align:start position:0% +that I can say there's just a script + + + align:start position:0% +that I can say there's just a script +there is no key but then I can only do + + align:start position:0% +there is no key but then I can only do + + + align:start position:0% +there is no key but then I can only do +it once right I can only have one thing + + align:start position:0% +it once right I can only have one thing + + + align:start position:0% +it once right I can only have one thing +the whole idea of graft root is I can + + align:start position:0% +the whole idea of graft root is I can + + + align:start position:0% +the whole idea of graft root is I can +have a million different scripts that + + align:start position:0% +have a million different scripts that + + + align:start position:0% +have a million different scripts that +are all going into one key okay so the + + align:start position:0% +are all going into one key okay so the + + + align:start position:0% +are all going into one key okay so the +problem is the root key must die in + + align:start position:0% +problem is the root key must die in + + + align:start position:0% +problem is the root key must die in +every script and now you need to use + + align:start position:0% +every script and now you need to use + + + align:start position:0% +every script and now you need to use +private keys to create an address that's + + align:start position:0% +private keys to create an address that's + + + align:start position:0% +private keys to create an address that's +not great right it's maybe okay but you + + align:start position:0% +not great right it's maybe okay but you + + + align:start position:0% +not great right it's maybe okay but you +haven't had to do that before so so now + + align:start position:0% +haven't had to do that before so so now + + + align:start position:0% +haven't had to do that before so so now +we have to sign off on every script that + + align:start position:0% +we have to sign off on every script that + + + align:start position:0% +we have to sign off on every script that +we're endorsing in order to compute an + + align:start position:0% +we're endorsing in order to compute an + + + align:start position:0% +we're endorsing in order to compute an +address you can do this after the fact + + align:start position:0% +address you can do this after the fact + + + align:start position:0% +address you can do this after the fact +though so that's kind of the interesting + + align:start position:0% +though so that's kind of the interesting + + + align:start position:0% +though so that's kind of the interesting +thing about this is you can say okay I'm + + align:start position:0% +thing about this is you can say okay I'm + + + align:start position:0% +thing about this is you can say okay I'm +sending the key C which is this root key + + align:start position:0% +sending the key C which is this root key + + + align:start position:0% +sending the key C which is this root key +that's all 50 participants and then + + align:start position:0% +that's all 50 participants and then + + + align:start position:0% +that's all 50 participants and then +after the fact after it's been confirmed + + align:start position:0% +after the fact after it's been confirmed + + + align:start position:0% +after the fact after it's been confirmed +in the blockchain those 50 participants + + align:start position:0% +in the blockchain those 50 participants + + + align:start position:0% +in the blockchain those 50 participants +can say actually you know what + + align:start position:0% +can say actually you know what + + + align:start position:0% +can say actually you know what +two of two of 50 is good we're not + + align:start position:0% +two of two of 50 is good we're not + + + align:start position:0% +two of two of 50 is good we're not +suspending the money right now but we're + + align:start position:0% +suspending the money right now but we're + + + align:start position:0% +suspending the money right now but we're +all agreeing that yeah any two of us can + + align:start position:0% +all agreeing that yeah any two of us can + + + align:start position:0% +all agreeing that yeah any two of us can +spend this money later and so they all + + align:start position:0% +spend this money later and so they all + + + align:start position:0% +spend this money later and so they all +get together and all 50 sign with the + + align:start position:0% +get together and all 50 sign with the + + + align:start position:0% +get together and all 50 sign with the +root key see all the different scripts + + align:start position:0% +root key see all the different scripts + + + align:start position:0% +root key see all the different scripts +those 1225 scripts and then hand those + + align:start position:0% +those 1225 scripts and then hand those + + + align:start position:0% +those 1225 scripts and then hand those +signatures out to the respective people + + align:start position:0% +signatures out to the respective people + + + align:start position:0% +signatures out to the respective people +who who would be interested in that + + align:start position:0% +who who would be interested in that + + + align:start position:0% +who who would be interested in that +signature right so Alice and Bob if you + + align:start position:0% +signature right so Alice and Bob if you + + + align:start position:0% +signature right so Alice and Bob if you +want to spend the money we all made a + + align:start position:0% +want to spend the money we all made a + + + align:start position:0% +want to spend the money we all made a +signature endorsing your - of - you know + + align:start position:0% +signature endorsing your - of - you know + + + align:start position:0% +signature endorsing your - of - you know +- of 50 your two keys and Bob and Carol + + align:start position:0% +- of 50 your two keys and Bob and Carol + + + align:start position:0% +- of 50 your two keys and Bob and Carol +if you two want to spend the money we've + + align:start position:0% +if you two want to spend the money we've + + + align:start position:0% +if you two want to spend the money we've +made a script + + align:start position:0% +made a script + + + align:start position:0% +made a script +that's a you know that's endorsed by us + + align:start position:0% +that's a you know that's endorsed by us + + + align:start position:0% +that's a you know that's endorsed by us +saying your two keys can spend it it's + + align:start position:0% +saying your two keys can spend it it's + + + align:start position:0% +saying your two keys can spend it it's +really cool the overhead is one + + align:start position:0% +really cool the overhead is one + + + align:start position:0% +really cool the overhead is one +signature so you can have that like + + align:start position:0% +signature so you can have that like + + + align:start position:0% +signature so you can have that like +hundred trillion different you know 2050 + + align:start position:0% +hundred trillion different you know 2050 + + + align:start position:0% +hundred trillion different you know 2050 +choose 25 which is 100 trillion well you + + align:start position:0% +choose 25 which is 100 trillion well you + + + align:start position:0% +choose 25 which is 100 trillion well you +got a sign 100 trillion times but when + + align:start position:0% +got a sign 100 trillion times but when + + + align:start position:0% +got a sign 100 trillion times but when +you spend from it it's small it's an + + align:start position:0% +you spend from it it's small it's an + + + align:start position:0% +you spend from it it's small it's an +extra thirty three bytes of overhead + + align:start position:0% +extra thirty three bytes of overhead + + + align:start position:0% +extra thirty three bytes of overhead +yeah the overhead is just a signature + + align:start position:0% +yeah the overhead is just a signature + + + align:start position:0% +yeah the overhead is just a signature +right so you say okay here's key see + + align:start position:0% +right so you say okay here's key see + + + align:start position:0% +right so you say okay here's key see +here's a signature from it here's the + + align:start position:0% +here's a signature from it here's the + + + align:start position:0% +here's a signature from it here's the +script to endorse the script being + + align:start position:0% +script to endorse the script being + + + align:start position:0% +script to endorse the script being +executed it's not actually 64 bytes you + + align:start position:0% +executed it's not actually 64 bytes you + + + align:start position:0% +executed it's not actually 64 bytes you +can get the overhead in 233 bytes + + align:start position:0% +can get the overhead in 233 bytes + + + align:start position:0% +can get the overhead in 233 bytes +because you can aggregate the s values + + align:start position:0% +because you can aggregate the s values + + + align:start position:0% +because you can aggregate the s values +of the signature I'll talk about this on + + align:start position:0% +of the signature I'll talk about this on + + + align:start position:0% +of the signature I'll talk about this on +Wednesday I don't think I actually came + + align:start position:0% +Wednesday I don't think I actually came + + + align:start position:0% +Wednesday I don't think I actually came +up with this but Greg cites me on it and + + align:start position:0% +up with this but Greg cites me on it and + + + align:start position:0% +up with this but Greg cites me on it and +it's like a yes no one thought of this + + align:start position:0% +it's like a yes no one thought of this + + + align:start position:0% +it's like a yes no one thought of this +huh but there's like a non-interactive + + align:start position:0% +huh but there's like a non-interactive + + + align:start position:0% +huh but there's like a non-interactive +partial aggregation of these things + + align:start position:0% +partial aggregation of these things + + + align:start position:0% +partial aggregation of these things +which I was really hoping we'd get into + + align:start position:0% +which I was really hoping we'd get into + + + align:start position:0% +which I was really hoping we'd get into +Bitcoin itself but I think it's too slow + + align:start position:0% +Bitcoin itself but I think it's too slow + + + align:start position:0% +Bitcoin itself but I think it's too slow +but in this case it's not that slow so + + align:start position:0% +but in this case it's not that slow so + + + align:start position:0% +but in this case it's not that slow so +people like yeah we'll use it here okay + + align:start position:0% +people like yeah we'll use it here okay + + + align:start position:0% +people like yeah we'll use it here okay +so this is kind of cool because it's + + align:start position:0% +so this is kind of cool because it's + + + align:start position:0% +so this is kind of cool because it's +simple right it's just more scripts can + + align:start position:0% +simple right it's just more scripts can + + + align:start position:0% +simple right it's just more scripts can +be at at any time it's all one scaling + + align:start position:0% +be at at any time it's all one scaling + + + align:start position:0% +be at at any time it's all one scaling +so if you have a million different + + align:start position:0% +so if you have a million different + + + align:start position:0% +so if you have a million different +scripts proving one of them just takes + + align:start position:0% +scripts proving one of them just takes + + + align:start position:0% +scripts proving one of them just takes +32 bytes or 33 or something C can be a + + align:start position:0% +32 bytes or 33 or something C can be a + + + align:start position:0% +32 bytes or 33 or something C can be a +threshold signature of many different + + align:start position:0% +threshold signature of many different + + + align:start position:0% +threshold signature of many different +parties the signature can be aggregated + + align:start position:0% +parties the signature can be aggregated + + + align:start position:0% +parties the signature can be aggregated +within the transaction + + align:start position:0% +within the transaction + + + align:start position:0% +within the transaction +the downside is this interactive setup + + align:start position:0% +the downside is this interactive setup + + + align:start position:0% +the downside is this interactive setup +where you can't just take Alice and Bob + + align:start position:0% +where you can't just take Alice and Bob + + + align:start position:0% +where you can't just take Alice and Bob +and Carols key and send to a graph route + + align:start position:0% +and Carols key and send to a graph route + + + align:start position:0% +and Carols key and send to a graph route +to a three multi-sig right Alice and Bob + + align:start position:0% +to a three multi-sig right Alice and Bob + + + align:start position:0% +to a three multi-sig right Alice and Bob +and Carol need to sign something in some + + align:start position:0% +and Carol need to sign something in some + + + align:start position:0% +and Carol need to sign something in some +cases that's no big deal + + align:start position:0% +cases that's no big deal + + + align:start position:0% +cases that's no big deal +right in some cases your connect to them + + align:start position:0% +right in some cases your connect to them + + + align:start position:0% +right in some cases your connect to them +over the internet and all the + + align:start position:0% +over the internet and all the + + + align:start position:0% +over the internet and all the +participants are cooperating sure will + + align:start position:0% +participants are cooperating sure will + + + align:start position:0% +participants are cooperating sure will +sign will create addresses or will pre + + align:start position:0% +sign will create addresses or will pre + + + align:start position:0% +sign will create addresses or will pre +sign all sorts of different addresses + + align:start position:0% +sign all sorts of different addresses + + + align:start position:0% +sign all sorts of different addresses +beforehand doable but sometimes you + + align:start position:0% +beforehand doable but sometimes you + + + align:start position:0% +beforehand doable but sometimes you +don't want this interactive set up + + align:start position:0% +don't want this interactive set up + + + align:start position:0% +don't want this interactive set up +sometimes I want to be able to send to + + align:start position:0% +sometimes I want to be able to send to + + + align:start position:0% +sometimes I want to be able to send to +participants of my choosing without + + align:start position:0% +participants of my choosing without + + + align:start position:0% +participants of my choosing without +their cooperation usually for standing + + align:start position:0% +their cooperation usually for standing + + + align:start position:0% +their cooperation usually for standing +people money they're ok with it right + + align:start position:0% +people money they're ok with it right + + + align:start position:0% +people money they're ok with it right +but sometimes you don't want them to be + + align:start position:0% +but sometimes you don't want them to be + + + align:start position:0% +but sometimes you don't want them to be +online okay + + align:start position:0% +online okay + + + align:start position:0% +online okay +so put this all together the idea and + + align:start position:0% +so put this all together the idea and + + + align:start position:0% +so put this all together the idea and +the + + align:start position:0% +the + + + align:start position:0% +the +the goal for this and I think the way + + align:start position:0% +the goal for this and I think the way + + + align:start position:0% +the goal for this and I think the way +it's gonna work in Bitcoin but this is + + align:start position:0% +it's gonna work in Bitcoin but this is + + + align:start position:0% +it's gonna work in Bitcoin but this is +still you know research kind of you have + + align:start position:0% +still you know research kind of you have + + + align:start position:0% +still you know research kind of you have +a unified output script so let's say + + align:start position:0% +a unified output script so let's say + + + align:start position:0% +a unified output script so let's say +it's a templated with op v and you say + + align:start position:0% +it's a templated with op v and you say + + + align:start position:0% +it's a templated with op v and you say +okay op v pub key now when i want to + + align:start position:0% +okay op v pub key now when i want to + + + align:start position:0% +okay op v pub key now when i want to +spend to it i have a bunch of options to + + align:start position:0% +spend to it i have a bunch of options to + + + align:start position:0% +spend to it i have a bunch of options to +spend I can just put a signature on the + + align:start position:0% +spend I can just put a signature on the + + + align:start position:0% +spend I can just put a signature on the +stack and then the program says oh + + align:start position:0% +stack and then the program says oh + + + align:start position:0% +stack and then the program says oh +there's a signature let me check if the + + align:start position:0% +there's a signature let me check if the + + + align:start position:0% +there's a signature let me check if the +signature matches the public key + + align:start position:0% +signature matches the public key + + + align:start position:0% +signature matches the public key +you know this funky and if it does cool + + align:start position:0% +you know this funky and if it does cool + + + align:start position:0% +you know this funky and if it does cool +the move money moves + + align:start position:0% +the move money moves + + + align:start position:0% +the move money moves +that's pub pay to pub key hash mode + + align:start position:0% +that's pub pay to pub key hash mode + + + align:start position:0% +that's pub pay to pub key hash mode +except it's not a match + + align:start position:0% +except it's not a match + + + align:start position:0% +except it's not a match +another thing I can do is provide a + + align:start position:0% +another thing I can do is provide a + + + align:start position:0% +another thing I can do is provide a +point J a script and a series of + + align:start position:0% +point J a script and a series of + + + align:start position:0% +point J a script and a series of +arguments for the script and that's + + align:start position:0% +arguments for the script and that's + + + align:start position:0% +arguments for the script and that's +Tapper I verify that J plus the you know + + align:start position:0% +Tapper I verify that J plus the you know + + + align:start position:0% +Tapper I verify that J plus the you know +I verify that J plus the hash of J and + + align:start position:0% +I verify that J plus the hash of J and + + + align:start position:0% +I verify that J plus the hash of J and +the script times G is equal to that pump + + align:start position:0% +the script times G is equal to that pump + + + align:start position:0% +the script times G is equal to that pump +key and then I execute that script + + align:start position:0% +key and then I execute that script + + + align:start position:0% +key and then I execute that script +another way to do it is if I've got this + + align:start position:0% +another way to do it is if I've got this + + + align:start position:0% +another way to do it is if I've got this +I've got C which is also just a point + + align:start position:0% +I've got C which is also just a point + + + align:start position:0% +I've got C which is also just a point +and I signature on the script and then a + + align:start position:0% +and I signature on the script and then a + + + align:start position:0% +and I signature on the script and then a +script and a bunch of arguments then I + + align:start position:0% +script and a bunch of arguments then I + + + align:start position:0% +script and a bunch of arguments then I +say oh this is crafter I'll verify this + + align:start position:0% +say oh this is crafter I'll verify this + + + align:start position:0% +say oh this is crafter I'll verify this +script this signature on this script and + + align:start position:0% +script this signature on this script and + + + align:start position:0% +script this signature on this script and +then execute with these arguments so I + + align:start position:0% +then execute with these arguments so I + + + align:start position:0% +then execute with these arguments so I +was it would be cool if you could do it + + align:start position:0% +was it would be cool if you could do it + + + align:start position:0% +was it would be cool if you could do it +just based on the number of items pushed + + align:start position:0% +just based on the number of items pushed + + + align:start position:0% +just based on the number of items pushed +but you might want to put like a flag or + + align:start position:0% +but you might want to put like a flag or + + + align:start position:0% +but you might want to put like a flag or +something here to distinguish between + + align:start position:0% +something here to distinguish between + + + align:start position:0% +something here to distinguish between +these two if it's this if there's just + + align:start position:0% +these two if it's this if there's just + + + align:start position:0% +these two if it's this if there's just +one element you can just quickly say + + align:start position:0% +one element you can just quickly say + + + align:start position:0% +one element you can just quickly say +okay it's made of funky but to + + align:start position:0% +okay it's made of funky but to + + + align:start position:0% +okay it's made of funky but to +distinguish between these two there + + align:start position:0% +distinguish between these two there + + + align:start position:0% +distinguish between these two there +might be weird edge cases where it's + + align:start position:0% +might be weird edge cases where it's + + + align:start position:0% +might be weird edge cases where it's +like well one of the arguments could + + align:start position:0% +like well one of the arguments could + + + align:start position:0% +like well one of the arguments could +also look like a script and annoying + + align:start position:0% +also look like a script and annoying + + + align:start position:0% +also look like a script and annoying +thing so you might put some like flag + + align:start position:0% +thing so you might put some like flag + + + align:start position:0% +thing so you might put some like flag +bite but anyway it's kind of nice in + + align:start position:0% +bite but anyway it's kind of nice in + + + align:start position:0% +bite but anyway it's kind of nice in +that when you send to an output you send + + align:start position:0% +that when you send to an output you send + + + align:start position:0% +that when you send to an output you send +to an address all the addresses look the + + align:start position:0% +to an address all the addresses look the + + + align:start position:0% +to an address all the addresses look the +same they just look like public keys but + + align:start position:0% +same they just look like public keys but + + + align:start position:0% +same they just look like public keys but +they could be any of these things and + + align:start position:0% +they could be any of these things and + + + align:start position:0% +they could be any of these things and +you only find out after the fact + + align:start position:0% + + + + align:start position:0% + +in not only that you could have the same + + align:start position:0% +in not only that you could have the same + + + align:start position:0% +in not only that you could have the same +key have a taproot and also have a + + align:start position:0% +key have a taproot and also have a + + + align:start position:0% +key have a taproot and also have a +grafter right you could you could have + + align:start position:0% +grafter right you could you could have + + + align:start position:0% +grafter right you could you could have +you know so they're clear + + align:start position:0% +you know so they're clear + + + align:start position:0% +you know so they're clear +in a dress and I've gotten my wallet + + align:start position:0% +in a dress and I've gotten my wallet + + + align:start position:0% +in a dress and I've gotten my wallet +well there's three different ways I can + + align:start position:0% +well there's three different ways I can + + + align:start position:0% +well there's three different ways I can +spend this I can spend this with + + align:start position:0% +spend this I can spend this with + + + align:start position:0% +spend this I can spend this with +everyone all 50 people signing or I can + + align:start position:0% +everyone all 50 people signing or I can + + + align:start position:0% +everyone all 50 people signing or I can +spend it with the like you know a single + + align:start position:0% +spend it with the like you know a single + + + align:start position:0% +spend it with the like you know a single +script that's been endorsed this way + + align:start position:0% +script that's been endorsed this way + + + align:start position:0% +script that's been endorsed this way +that's got like priority and then I can + + align:start position:0% +that's got like priority and then I can + + + align:start position:0% +that's got like priority and then I can +also spend it with one of the millions + + align:start position:0% +also spend it with one of the millions + + + align:start position:0% +also spend it with one of the millions +of scripts that have been endorsed this + + align:start position:0% +of scripts that have been endorsed this + + + align:start position:0% +of scripts that have been endorsed this +way so I can use all three this is a + + align:start position:0% +way so I can use all three this is a + + + align:start position:0% +way so I can use all three this is a +little bit more efficient right because + + align:start position:0% +little bit more efficient right because + + + align:start position:0% +little bit more efficient right because +you're just revealing the script and a + + align:start position:0% +you're just revealing the script and a + + + align:start position:0% +you're just revealing the script and a +point this one you have to reveal + + align:start position:0% +point this one you have to reveal + + + align:start position:0% +point this one you have to reveal +oh no wait sorry this is wrong there's + + align:start position:0% +oh no wait sorry this is wrong there's + + + align:start position:0% +oh no wait sorry this is wrong there's +no see you already know see it's it's + + align:start position:0% +no see you already know see it's it's + + + align:start position:0% +no see you already know see it's it's +still a little more efficient yeah + + align:start position:0% +still a little more efficient yeah + + + align:start position:0% +still a little more efficient yeah +there's no see there you already know + + align:start position:0% +there's no see there you already know + + + align:start position:0% +there's no see there you already know +see you just put the signature on the + + align:start position:0% +see you just put the signature on the + + + align:start position:0% +see you just put the signature on the +script yeah okay so this is graph root + + align:start position:0% +script yeah okay so this is graph root + + + align:start position:0% +script yeah okay so this is graph root +tap root and then also part of the + + align:start position:0% +tap root and then also part of the + + + align:start position:0% +tap root and then also part of the +script can be masked you can have a mask + + align:start position:0% +script can be masked you can have a mask + + + align:start position:0% +script can be masked you can have a mask +top code you can combine all these + + align:start position:0% +top code you can combine all these + + + align:start position:0% +top code you can combine all these +things in crazy ways and have like + + align:start position:0% +things in crazy ways and have like + + + align:start position:0% +things in crazy ways and have like +really powerful scripting that way okay + + align:start position:0% +really powerful scripting that way okay + + + align:start position:0% +really powerful scripting that way okay +so when this stuff was proposed the + + align:start position:0% +so when this stuff was proposed the + + + align:start position:0% +so when this stuff was proposed the +argument was hey I don't want to spend + + align:start position:0% +argument was hey I don't want to spend + + + align:start position:0% +argument was hey I don't want to spend +to a public key I want to spend to a + + align:start position:0% +to a public key I want to spend to a + + + align:start position:0% +to a public key I want to spend to a +public key hash because quantum + + align:start position:0% +public key hash because quantum + + + align:start position:0% +public key hash because quantum +computers are coming and when the + + align:start position:0% +computers are coming and when the + + + align:start position:0% +computers are coming and when the +quantum computers come if you know my + + align:start position:0% +quantum computers come if you know my + + + align:start position:0% +quantum computers come if you know my +pub key you can just calculate my + + align:start position:0% +pub key you can just calculate my + + + align:start position:0% +pub key you can just calculate my +private key and take all my money but if + + align:start position:0% +private key and take all my money but if + + + align:start position:0% +private key and take all my money but if +you only know my public key hash quantum + + align:start position:0% +you only know my public key hash quantum + + + align:start position:0% +you only know my public key hash quantum +computer doesn't help you there right + + align:start position:0% +computer doesn't help you there right + + + align:start position:0% +computer doesn't help you there right +you're not going to be able to compute + + align:start position:0% +you're not going to be able to compute + + + align:start position:0% +you're not going to be able to compute +the preimage of a hash with the quantum + + align:start position:0% +the preimage of a hash with the quantum + + + align:start position:0% +the preimage of a hash with the quantum +computer there's yeah that's true all of + + align:start position:0% +computer there's yeah that's true all of + + + align:start position:0% +computer there's yeah that's true all of +those statements are true except in + + align:start position:0% +those statements are true except in + + + align:start position:0% +those statements are true except in +practice it's it's dumb because if + + align:start position:0% +practice it's it's dumb because if + + + align:start position:0% +practice it's it's dumb because if +there's a quantum computer that can + + align:start position:0% +there's a quantum computer that can + + + align:start position:0% +there's a quantum computer that can +compute your private key from your + + align:start position:0% +compute your private key from your + + + align:start position:0% +compute your private key from your +public key + + align:start position:0% +public key + + + align:start position:0% +public key +the only time using Punky hashes will + + align:start position:0% +the only time using Punky hashes will + + + align:start position:0% +the only time using Punky hashes will +help you is if somehow that quantum + + align:start position:0% +help you is if somehow that quantum + + + align:start position:0% +help you is if somehow that quantum +computer takes a really long time to + + align:start position:0% +computer takes a really long time to + + + align:start position:0% +computer takes a really long time to +compute your private key right because + + align:start position:0% +compute your private key right because + + + align:start position:0% +compute your private key right because +if it only takes them a minute to + + align:start position:0% +if it only takes them a minute to + + + align:start position:0% +if it only takes them a minute to +compute it well you have to reveal your + + align:start position:0% +compute it well you have to reveal your + + + align:start position:0% +compute it well you have to reveal your +public key to spend your money and then + + align:start position:0% +public key to spend your money and then + + + align:start position:0% +public key to spend your money and then +the attacker who has this nifty quantum + + align:start position:0% +the attacker who has this nifty quantum + + + align:start position:0% +the attacker who has this nifty quantum +computer can just say oh that's his + + align:start position:0% +computer can just say oh that's his + + + align:start position:0% +computer can just say oh that's his +public key I just saw it right + + align:start position:0% +public key I just saw it right + + + align:start position:0% +public key I just saw it right +and he signed and using his bubble key I + + align:start position:0% +and he signed and using his bubble key I + + + align:start position:0% +and he signed and using his bubble key I +just computers private key sign a + + align:start position:0% +just computers private key sign a + + + align:start position:0% +just computers private key sign a +different message and broadcast it and + + align:start position:0% +different message and broadcast it and + + + align:start position:0% +different message and broadcast it and +maybe I attach a higher fee because I + + align:start position:0% +maybe I attach a higher fee because I + + + align:start position:0% +maybe I attach a higher fee because I +don't care it's not my money and the + + align:start position:0% +don't care it's not my money and the + + + align:start position:0% +don't care it's not my money and the +miners are like well there's two + + align:start position:0% +miners are like well there's two + + + align:start position:0% +miners are like well there's two +different transactions one sending over + + align:start position:0% +different transactions one sending over + + + align:start position:0% +different transactions one sending over +here one sending over here this one has + + align:start position:0% +here one sending over here this one has + + + align:start position:0% +here one sending over here this one has +a much higher fee I'll use this one and + + align:start position:0% +a much higher fee I'll use this one and + + + align:start position:0% +a much higher fee I'll use this one and +the attacker with the quantum computer + + align:start position:0% +the attacker with the quantum computer + + + align:start position:0% +the attacker with the quantum computer +still takes all your money they can't + + align:start position:0% +still takes all your money they can't + + + align:start position:0% +still takes all your money they can't +take it at rest they have to wait for + + align:start position:0% +take it at rest they have to wait for + + + align:start position:0% +take it at rest they have to wait for +you to try to spend it and take it but + + align:start position:0% +you to try to spend it and take it but + + + align:start position:0% +you to try to spend it and take it but +you could say okay well actually I'm + + align:start position:0% +you could say okay well actually I'm + + + align:start position:0% +you could say okay well actually I'm +moving up five paid Punky hash and then + + align:start position:0% +moving up five paid Punky hash and then + + + align:start position:0% +moving up five paid Punky hash and then +for this I have to reveal pumpking + + align:start position:0% +for this I have to reveal pumpking + + + align:start position:0% +for this I have to reveal pumpking +signature for this I reveal pub key J + + align:start position:0% +signature for this I reveal pub key J + + + align:start position:0% +signature for this I reveal pub key J +component of pump key script for this I + + align:start position:0% +component of pump key script for this I + + + align:start position:0% +component of pump key script for this I +revealed you know see you missing but + + align:start position:0% +revealed you know see you missing but + + + align:start position:0% +revealed you know see you missing but +it's like kind of ugly waste of space + + align:start position:0% +it's like kind of ugly waste of space + + + align:start position:0% +it's like kind of ugly waste of space +and in most cases doesn't provide a lot + + align:start position:0% +and in most cases doesn't provide a lot + + + align:start position:0% +and in most cases doesn't provide a lot +of protection + + align:start position:0% +of protection + + + align:start position:0% +of protection +so there's hopefully better ways to deal + + align:start position:0% +so there's hopefully better ways to deal + + + align:start position:0% +so there's hopefully better ways to deal +with this one thing that I have sort of + + align:start position:0% +with this one thing that I have sort of + + + align:start position:0% +with this one thing that I have sort of +been joking about but it would be kind + + align:start position:0% +been joking about but it would be kind + + + align:start position:0% +been joking about but it would be kind +of fun to put it into wallets you can + + align:start position:0% +of fun to put it into wallets you can + + + align:start position:0% +of fun to put it into wallets you can +actually use tap root to commit to a + + align:start position:0% +actually use tap root to commit to a + + + align:start position:0% +actually use tap root to commit to a +Lamport like hash based pub key so in + + align:start position:0% +Lamport like hash based pub key so in + + + align:start position:0% +Lamport like hash based pub key so in +tap root this is actually quantum secure + + align:start position:0% +tap root this is actually quantum secure + + + align:start position:0% +tap root this is actually quantum secure +I hesitate to advertise this but it is a + + align:start position:0% +I hesitate to advertise this but it is a + + + align:start position:0% +I hesitate to advertise this but it is a +commitment that is not that the quantum + + align:start position:0% +commitment that is not that the quantum + + + align:start position:0% +commitment that is not that the quantum +computer cannot Forge right the the the + + align:start position:0% +computer cannot Forge right the the the + + + align:start position:0% +computer cannot Forge right the the the +whole wait where does it where as I + + align:start position:0% +whole wait where does it where as I + + + align:start position:0% +whole wait where does it where as I +saying the J equals hash of yeah this + + align:start position:0% +saying the J equals hash of yeah this + + + align:start position:0% +saying the J equals hash of yeah this +thing is still a problem for a quantum + + align:start position:0% +thing is still a problem for a quantum + + + align:start position:0% +thing is still a problem for a quantum +computer right you got I want to compute + + align:start position:0% +computer right you got I want to compute + + + align:start position:0% +computer right you got I want to compute +a J such that J equals this hash times G + + align:start position:0% +a J such that J equals this hash times G + + + align:start position:0% +a J such that J equals this hash times G +minus R the Jim J is in there as well + + align:start position:0% +minus R the Jim J is in there as well + + + align:start position:0% +minus R the Jim J is in there as well +even with a quantum computer maybe I can + + align:start position:0% +even with a quantum computer maybe I can + + + align:start position:0% +even with a quantum computer maybe I can +compute an arbitrary J and find its + + align:start position:0% +compute an arbitrary J and find its + + + align:start position:0% +compute an arbitrary J and find its +discrete log you know find the private + + align:start position:0% +discrete log you know find the private + + + align:start position:0% +discrete log you know find the private +key but it's still not going to satisfy + + align:start position:0% +key but it's still not going to satisfy + + + align:start position:0% +key but it's still not going to satisfy +this equation so I can't find I can't + + align:start position:0% +this equation so I can't find I can't + + + align:start position:0% +this equation so I can't find I can't +after the fact find a script in a J to + + align:start position:0% +after the fact find a script in a J to + + + align:start position:0% +after the fact find a script in a J to +compute + + align:start position:0% +compute + + + align:start position:0% +compute +see so that is safe even if a quantum + + align:start position:0% +see so that is safe even if a quantum + + + align:start position:0% +see so that is safe even if a quantum +computer exists right because that's + + align:start position:0% +computer exists right because that's + + + align:start position:0% +computer exists right because that's +based on the security the hash function + + align:start position:0% +based on the security the hash function + + + align:start position:0% +based on the security the hash function +so that's kind of an interesting little + + align:start position:0% +so that's kind of an interesting little + + + align:start position:0% +so that's kind of an interesting little +tidbit like hey this is this taproot + + align:start position:0% +tidbit like hey this is this taproot + + + align:start position:0% +tidbit like hey this is this taproot +construction this is hash based quantum + + align:start position:0% +construction this is hash based quantum + + + align:start position:0% +construction this is hash based quantum +computer appears and we say look we no + + align:start position:0% +computer appears and we say look we no + + + align:start position:0% +computer appears and we say look we no +longer allow C we no longer allow the + + align:start position:0% +longer allow C we no longer allow the + + + align:start position:0% +longer allow C we no longer allow the +normal spend where you sign with key C + + align:start position:0% +normal spend where you sign with key C + + + align:start position:0% +normal spend where you sign with key C +because signature is all this elliptic + + align:start position:0% +because signature is all this elliptic + + + align:start position:0% +because signature is all this elliptic +curve stuff it's broken however we do + + align:start position:0% +curve stuff it's broken however we do + + + align:start position:0% +curve stuff it's broken however we do +allow you to prove that there was a + + align:start position:0% +allow you to prove that there was a + + + align:start position:0% +allow you to prove that there was a +script Z can you know can committed to + + align:start position:0% +script Z can you know can committed to + + + align:start position:0% +script Z can you know can committed to +in C and then maybe this script has like + + align:start position:0% +in C and then maybe this script has like + + + align:start position:0% +in C and then maybe this script has like +a quantum safe signature in it and then + + align:start position:0% +a quantum safe signature in it and then + + + align:start position:0% +a quantum safe signature in it and then +we can use that what's nice about that + + align:start position:0% +we can use that what's nice about that + + + align:start position:0% +we can use that what's nice about that +is you can start using it sooner and + + align:start position:0% +is you can start using it sooner and + + + align:start position:0% +is you can start using it sooner and +without the overhead of all the extra + + align:start position:0% +without the overhead of all the extra + + + align:start position:0% +without the overhead of all the extra +space taken by the quantum signature + + align:start position:0% +space taken by the quantum signature + + + align:start position:0% +space taken by the quantum signature +because it's sort of a back-up plan it's + + align:start position:0% +because it's sort of a back-up plan it's + + + align:start position:0% +because it's sort of a back-up plan it's +like well normally I'm just signing with + + align:start position:0% +like well normally I'm just signing with + + + align:start position:0% +like well normally I'm just signing with +C right because I know what you know + + align:start position:0% +C right because I know what you know + + + align:start position:0% +C right because I know what you know +this is just my regular key and I do + + align:start position:0% +this is just my regular key and I do + + + align:start position:0% +this is just my regular key and I do +this but worst case scenario if a + + align:start position:0% +this but worst case scenario if a + + + align:start position:0% +this but worst case scenario if a +quantum computer appears in ten years + + align:start position:0% +quantum computer appears in ten years + + + align:start position:0% +quantum computer appears in ten years +I've got my other backup key here so + + align:start position:0% +I've got my other backup key here so + + + align:start position:0% +I've got my other backup key here so +that's kind of a cool thing I don't know + + align:start position:0% +that's kind of a cool thing I don't know + + + align:start position:0% +that's kind of a cool thing I don't know +how useful it is in practice but okay so + + align:start position:0% +how useful it is in practice but okay so + + + align:start position:0% +how useful it is in practice but okay so +yeah you got all these three things the + + align:start position:0% +yeah you got all these three things the + + + align:start position:0% +yeah you got all these three things the +other thing about this is I don't know + + align:start position:0% +other thing about this is I don't know + + + align:start position:0% +other thing about this is I don't know +big multi-sig is one use case it seems + + align:start position:0% +big multi-sig is one use case it seems + + + align:start position:0% +big multi-sig is one use case it seems +really powerful and like hey I can make + + align:start position:0% +really powerful and like hey I can make + + + align:start position:0% +really powerful and like hey I can make +these you know millions of different + + align:start position:0% +these you know millions of different + + + align:start position:0% +these you know millions of different +scripts and like Merkle trees of + + align:start position:0% +scripts and like Merkle trees of + + + align:start position:0% +scripts and like Merkle trees of +different scripts and tappero and + + align:start position:0% +different scripts and tappero and + + + align:start position:0% +different scripts and tappero and +graphic not a ton of like really good + + align:start position:0% +graphic not a ton of like really good + + + align:start position:0% +graphic not a ton of like really good +real-world use cases though I think that + + align:start position:0% +real-world use cases though I think that + + + align:start position:0% +real-world use cases though I think that +would motivate it a lot more because a + + align:start position:0% +would motivate it a lot more because a + + + align:start position:0% +would motivate it a lot more because a +lot of it a lot of the hesitation from + + align:start position:0% +lot of it a lot of the hesitation from + + + align:start position:0% +lot of it a lot of the hesitation from +people working on Bitcoin it's like okay + + align:start position:0% +people working on Bitcoin it's like okay + + + align:start position:0% +people working on Bitcoin it's like okay +what this is really cool but like what + + align:start position:0% +what this is really cool but like what + + + align:start position:0% +what this is really cool but like what +are we gonna do with it + + align:start position:0% +are we gonna do with it + + + align:start position:0% +are we gonna do with it +and multi-sig is not as I'll talk about + + align:start position:0% +and multi-sig is not as I'll talk about + + + align:start position:0% +and multi-sig is not as I'll talk about +and Wednesday multi-sig itself is not + + align:start position:0% +and Wednesday multi-sig itself is not + + + align:start position:0% +and Wednesday multi-sig itself is not +the best motivation because once we have + + align:start position:0% +the best motivation because once we have + + + align:start position:0% +the best motivation because once we have +more signatures and aggregate signatures + + align:start position:0% +more signatures and aggregate signatures + + + align:start position:0% +more signatures and aggregate signatures +there's direct ways to do multi-sig that + + align:start position:0% +there's direct ways to do multi-sig that + + + align:start position:0% +there's direct ways to do multi-sig that +are actually more privacy-preserving + + align:start position:0% +are actually more privacy-preserving + + + align:start position:0% +are actually more privacy-preserving +more space preserving so we need use + + align:start position:0% +more space preserving so we need use + + + align:start position:0% +more space preserving so we need use +cases and that was that's one of the + + align:start position:0% +cases and that was that's one of the + + + align:start position:0% +cases and that was that's one of the +debates like okay what do we do with + + align:start position:0% +debates like okay what do we do with + + + align:start position:0% +debates like okay what do we do with +this this is kind of cool you can make + + align:start position:0% +this this is kind of cool you can make + + + align:start position:0% +this this is kind of cool you can make +all sorts of weird smart contracts but + + align:start position:0% +all sorts of weird smart contracts but + + + align:start position:0% +all sorts of weird smart contracts but +what are some + + align:start position:0% +what are some + + + align:start position:0% +what are some +world news cases there's also sort of + + align:start position:0% +world news cases there's also sort of + + + align:start position:0% +world news cases there's also sort of +argument okay mast versus graph route + + align:start position:0% +argument okay mast versus graph route + + + align:start position:0% +argument okay mast versus graph route +versus both well if you have graphed + + align:start position:0% +versus both well if you have graphed + + + align:start position:0% +versus both well if you have graphed +route do you really need mast anymore + + align:start position:0% +route do you really need mast anymore + + + align:start position:0% +route do you really need mast anymore +right instead of this big Merkel tree + + align:start position:0% +right instead of this big Merkel tree + + + align:start position:0% +right instead of this big Merkel tree +you just have the signatures endorsing + + align:start position:0% +you just have the signatures endorsing + + + align:start position:0% +you just have the signatures endorsing +the leaves so it sort of seems better + + align:start position:0% +the leaves so it sort of seems better + + + align:start position:0% +the leaves so it sort of seems better +scalability there but grassroots + + align:start position:0% +scalability there but grassroots + + + align:start position:0% +scalability there but grassroots +interactive so maybe you still want + + align:start position:0% +interactive so maybe you still want + + + align:start position:0% +interactive so maybe you still want +masked maybe have both there's all sorts + + align:start position:0% +masked maybe have both there's all sorts + + + align:start position:0% +masked maybe have both there's all sorts +of debate on this and so that in + + align:start position:0% +of debate on this and so that in + + + align:start position:0% +of debate on this and so that in +practice they that may mean that sense + + align:start position:0% +practice they that may mean that sense + + + align:start position:0% +practice they that may mean that sense +people are arguing next year the year + + align:start position:0% +people are arguing next year the year + + + align:start position:0% +people are arguing next year the year +after it's hard to get everyone on board + + align:start position:0% +after it's hard to get everyone on board + + + align:start position:0% +after it's hard to get everyone on board +to do stuff there is code though some + + align:start position:0% +to do stuff there is code though some + + + align:start position:0% +to do stuff there is code though some +things have code some of them are like a + + align:start position:0% +things have code some of them are like a + + + align:start position:0% +things have code some of them are like a +lot of it's sort of obvious enough + + align:start position:0% +lot of it's sort of obvious enough + + + align:start position:0% +lot of it's sort of obvious enough +they're like yeah craft room makes sense + + align:start position:0% +they're like yeah craft room makes sense + + + align:start position:0% +they're like yeah craft room makes sense +just have them sign the taproot + + align:start position:0% +just have them sign the taproot + + + align:start position:0% +just have them sign the taproot +construction there's code for but it's + + align:start position:0% +construction there's code for but it's + + + align:start position:0% +construction there's code for but it's +not all like put together there's no + + align:start position:0% +not all like put together there's no + + + align:start position:0% +not all like put together there's no +like spec for all these things so if + + align:start position:0% +like spec for all these things so if + + + align:start position:0% +like spec for all these things so if +people are interested in this stuff + + align:start position:0% +people are interested in this stuff + + + align:start position:0% +people are interested in this stuff +start coding it start trying it out come + + align:start position:0% +start coding it start trying it out come + + + align:start position:0% +start coding it start trying it out come +up with cool use cases and maybe push + + align:start position:0% +up with cool use cases and maybe push + + + align:start position:0% +up with cool use cases and maybe push +for one thing or another to get in + + align:start position:0% +for one thing or another to get in + + + align:start position:0% +for one thing or another to get in +there's there's a pull request open in + + align:start position:0% +there's there's a pull request open in + + + align:start position:0% +there's there's a pull request open in +Bitcoin right now foremast I don't know + + align:start position:0% +Bitcoin right now foremast I don't know + + + align:start position:0% +Bitcoin right now foremast I don't know +some people are really into it and other + + align:start position:0% +some people are really into it and other + + + align:start position:0% +some people are really into it and other +people are like I don't know also how to + + align:start position:0% +people are like I don't know also how to + + + align:start position:0% +people are like I don't know also how to +implement math exactly so this is you + + align:start position:0% +implement math exactly so this is you + + + align:start position:0% +implement math exactly so this is you +know still research kind of level but I + + align:start position:0% +know still research kind of level but I + + + align:start position:0% +know still research kind of level but I +it seems that they're usable and that + + align:start position:0% +it seems that they're usable and that + + + align:start position:0% +it seems that they're usable and that +may improve some our contract + + align:start position:0% +may improve some our contract + + + align:start position:0% +may improve some our contract +functionality so cool stuff here any + + align:start position:0% +functionality so cool stuff here any + + + align:start position:0% +functionality so cool stuff here any +questions about this alright cool + + align:start position:0% +questions about this alright cool + + + align:start position:0% +questions about this alright cool +okay well so I'll do office hours + + align:start position:0% +okay well so I'll do office hours + + + align:start position:0% +okay well so I'll do office hours +tomorrow at four we talk about projects + + align:start position:0% +tomorrow at four we talk about projects + + + align:start position:0% +tomorrow at four we talk about projects +and stuff and the next class on + + align:start position:0% +and stuff and the next class on + + + align:start position:0% +and stuff and the next class on +Wednesday will be even more crazy + + align:start position:0% +Wednesday will be even more crazy + + + align:start position:0% +Wednesday will be even more crazy +elliptic curve stuff about aggregate + + align:start position:0% +elliptic curve stuff about aggregate + + + align:start position:0% +elliptic curve stuff about aggregate +signatures for signatures multi + + align:start position:0% +signatures for signatures multi + + + align:start position:0% +signatures for signatures multi +signatures threshold signatures things + + align:start position:0% +signatures threshold signatures things + + + align:start position:0% +signatures threshold signatures things +like that weight and also privacy I + + align:start position:0% +like that weight and also privacy I + + + align:start position:0% +like that weight and also privacy I +don't know how much of I'm gonna focus + + align:start position:0% +don't know how much of I'm gonna focus + + + align:start position:0% +don't know how much of I'm gonna focus +on the signature part I also put like + + align:start position:0% +on the signature part I also put like + + + align:start position:0% +on the signature part I also put like +privacy and coin joint in there which is + + align:start position:0% +privacy and coin joint in there which is + + + align:start position:0% +privacy and coin joint in there which is +related but might be squished towards + + align:start position:0% +related but might be squished towards + + + align:start position:0% +related but might be squished towards +the end if I don't have a ton of time \ No newline at end of file diff --git a/hGBNi4P9OfA.txt b/hGBNi4P9OfA.txt new file mode 100644 index 0000000000000000000000000000000000000000..42ed2ef726c1034ecdd498bac20617add1e0e518 --- /dev/null +++ b/hGBNi4P9OfA.txt @@ -0,0 +1,4942 @@ +The following content is +provided under a Creative + +Commons license. + +Your support will help +MIT OpenCourseWare + +continue to offer high quality +educational resources for free. + +To make a donation or to +view additional materials + +from hundreds of MIT courses, +visit MIT OpenCourseWare + +at ocw.mit.edu. + +JANET RANKIN: A +general comment is by + +and large, I thought you +guys did a great job. + +Your learning outcomes +were for the most part + +specific, measurable, +and realistic. + +The biggest problem I think +I had was with-- the biggest + +problem that you +had on average was + +the idea of the +learning outcomes + +really have to be measurable. + +So if you use a word +like appreciate, + +it's not measurable. + +So that's something to remember. + +If you use words like discuss, +it's potentially measurable. + +But you need to make sure that +you set up a venue for students + +to discuss. + +You can't just say you'll be +able to discuss that and assume + +that they'll be +able to discuss it, + +That If that's in +your learning outcome, + +you have to set up some +venue for them to discuss + +and you to know what +they're discussing. + +And then the two biggest +things that come up, + +or the two most problematic +words that come up-- + +and I compliment you all, +because you did a great job. + +Nobody used understand. + +So that was awesome. + +But the other +thing, there's words + +like explain and describe, +which are perfectly good words + +to use in a learning outcome. + +But you have to make +sure that when you say, + +students will explain +the ideal gas law. + +They'll be able to +explain the ideal gas law. + +Well do you know that +they're really explaining it + +in the true sense of that +word that they actually + +internalized what it means, and +they're really explaining it? + +Or are they just spitting it +back, spitting back, maybe, + +what they read in a +book, a definition + +that they read in the book? + +So you have to make +sure that you've + +set up a situation wherein +they really are explaining. + +And they're not +just remembering. + +So it's a great word to use. + +But you have to +make sure that we're + +using in the right context. + +Same thing for describe. + +You can imagine that +has the same issues. + +Describe da, da da, da, da. + +Well are you sure they're +doing the describing? + +Or are they just remembering +somebody else's description + +and writing it down? + +One good way around +that is to tweak + +the parameters a little bit. + +To say, in a world where +there is no oxygen, + +what do you expect this +organism to look like, + +given that it has to run +really fast or something? + +So come up with +alternate realities + +that that actually force +students to transfer and then + +re-explain. + +That can be helpful. + +That can be really, +really helpful. + +I remember once in +a kinetics class, + +we had been deriving +the critical nucleus + +size for growth. + +And it's all based on a +radius, a critical radius. + +And then on the exam, +the guy said OK, + +they don't grow as sphere's. + +They grow as rectangular boxes. + +So then all of a +sudden, we had to look + +at the ratio of the length +to the height of the box + +or something. + +So that really wasn't +just we were just + +remembering a solution +or remembering a method. + +We had to actually think +about what it meant + +and then reapply it. + +So just think about how +you can get students + +to really describe, explain, +derive even, because you + +can memorize a derivation. + +But if you really want them to +derive it, what does that mean? + +How are you going to test that? + +So those are generally +the biggest problems + +people have with +learning outcomes. + +But by and large, you +all did a great job. + +If you came in late, I'll give +you your learning outcomes + +at the end to class. + +If you looked at the Wiki-- +and this is a test to see who + +looked at the Wiki-- + +I had suggested you bring a web +enabled device if you had one. + +And that's because +I wanted to set up + +something called Back +Channel The topic today + +is on active learning. + +And so this is just one method +that might help your students, + +especially if you +have a big class. + +So we don't really +need it in this class, + +but I just wanted to +give you the opportunity + +to play with it a little bit. + +It was designed for +conferences actually. + +But it works pretty well, +I think, in classes. + +So if you login to +here, this is the URL. + +If you go to our +Wiki page bookmarked, + +there's a link on the +Wiki page, if you just + +want to link to it that way. + +And then at any +point in the class, + +you can type a question in. + +And if you're on +the page, you can + +see other people's questions. + +You can upvote and +downvote their questions. + +And I will take a break +in the middle, when you're + +doing some other things, and +read what people have posted + +and then get back to you. + +So it's an opportunity +for students to interact + +who may be a little more +shy, who may not want to. + +I don't think we need +that in this class. + +I don't think that there's +any one of you that + +isn't willing to share +your ideas, which is great. + +But this may be something +that's of interest to you. + +Before we jump into the +topic today, active learning, + +there were a couple +of mud card questions + +that I just wanted +to talk about. + +One was sometimes students +may nod off during class. + +And if it's a big +class, there's probably + +not a lot you can do about it. + +If you do enough +active learning, + +though, that will keep them-- +that will make them wake up. + +Especially pair +activities or activities + +where they have to talk to +one or two other people, + +or two or three other +people, it's pretty hard + +to be asleep during those. + +And you'll see. + +We're going to do something +called a lightning round later + +on. + +And it's virtually impossible +to be asleep during that. + +So you want to make +sure that it's worth + +the student's time to +actually be in class + +and be awake for it. + +And active learning can +play a huge role in that. + +Sometimes people are tired. + +They stayed up too late +for whatever reason. + +And you can't control +everybody in your class. + +But you want to make sure that +you're doing everything you + +can do to keep them engaged. + +And if it's just one +student every now and then, + +you probably don't want +to take it personally. + +It's probably not you. + +If the whole class +is falling asleep, + +then it's probably +a good opportunity + +to rethink your strategies. + +Somebody asked if there +were good times of day + +to have a lecture. + +And part of it is you. + +Part of is your schedule. + +Sometimes you're allowed. + +You can pick that. + +And sometimes you really don't +have much control over when + +you choose to teach your class. + +People do say that +students, undergrads, + +people between the +ages of 18 and 21 + +are not particularly interested +in being up at 8:00 or 9:00 + +in the morning. + +But again you may not have +any control over that. + +Generally speaking, that's a +pretty low time for people. + +So if you want to take that +into consideration, you might. + +But it depends as much +on you as the students. + +If you're going to be +really tired at 4:00 + +but they're just waking up, +then don't teach it at 4:00. + +Maybe don't teach at 4:00. + +And the last one was +guiding readings. + +If you just put a +lot of readings up, + +students might not know where +to focus their attention + +until after the class. + +So there are reading +questions, reading guides + +that you can post. + +Read such and such +and try and think + +about how you might explain +this, that, or the other thing. + +And then there's also +pre-class questions + +you can ask that +they might derive, + +that they may have to pull +from the readings to answer. + +So the concept of just in +time teaching, the idea + +that students do +a reading and then + +they actually have to answer +questions on the reading + +before they come to class +and submit their answers. + +So there's a whole +procedure around that. + +It can be very, very effective. + +You can do it for a large class. + +There's strategies +and techniques + +to streamline the amount +of time you put into it. + +But it does force them +to do the reading. + +And it does guide, at some +level, what they read. + +And that's a great +great approach. + +And I'm happy to talk more about +that at another time or later + +or offline. + +I did go to the Teaching +with Technology conference, + +the Teaching Professor +Technology Conference. + +And they were giving out little +ribbons to stack on your badge. + +And this was a prominent one. + +It's in the syllabus, +which I thought + +was just crazy timely because +a couple of weeks ago. + +So if you want one of +these to stick somewhere. + +And then they all said when I +tweet, which was sort of weird. + +But anyway I brought those back. + +Anybody want some. + +Sometimes my computer +doesn't wake up. + +So let's pretend that instead +of the class active learning + +today, I decided I was going +to teach you how to juggle. + +And I said, here's the +equation for how to juggle. + +And here's the variables, +F, D, V N, and H, + +which are ball in the +air, ball in an hand, + +time hand is vacant, number +of balls, number of hands. + +And this is this +handy dandy equation, + +which if you balance it out, it +describes the juggling process. + +And for those of you +that are visual learners, + +I have a graph here, a +yellow ball, a blue ball, + +and a pink ball. + +And then you can see that just +shows the path of the balls. + +If you remember from +physics, there's + +the equations of motion in the +x direction in the y direction. + +And so I think I probably did a +pretty good job of teaching you + +how to juggle. + +No, did a terrible job of +teaching you how to juggle. + +I didn't even come close to +teaching you how to juggle. + +And if I were to +give you a test, + +let's say, and I were to +measure whether or not + +you could juggle, I +guarantee that some of you + +would be able to juggle. + +And I could say, I did a great +job teaching how to juggle. + +But I didn't. + +If you knew how to +juggle coming in, + +presumably you still +know how to juggle. + +I did no harm, I think. + +However if you didn't know +how to juggle coming in, + +you don't know +how to juggle now. + +So why is this here now? + +Why did I bother to +do this stupid thought + +experiment right now? + +AUDIENCE: Because +this is clearly + +how most classes are taught. + +Obviously it would be +easier to have a ball + +and show us how to juggle, +active learning as opposed + +to just showing the theory +behind it and ending there. + +JANET RANKIN: And I +think a lot of times + +we really do, in science and +engineering classes, we really + +put up a lot of equations. + +And then it's not like +we expect somebody + +to do something +physically with them. + +But we expect them to be able +to manipulate the equations, + +transfer the equations, +apply the equations. + +And we never really +talked about that. + +We talked about the equations. + +So it's a real call +in my mind, for us + +to think about what +it is we really + +want students to be able to do. + +And then make sure that +they're doing stuff + +to teach them that helps +them learn how to do that. + +And I know you all +read the readings + +and that they talk a lot +about active learning. + +There's a few things about +techniques for active learning. + +There's a few things about +the why's of active learning. + +There's some data for why +active learning works. + +But I'm guessing that +there's a range of buy in + +at this point from you guys. + +Eh, I don't think it's worth it. + +Or I don't really know. + +So for the first 20 +minutes, 25 minutes + +of class, what +I'd like you to do + +is I'd like you to +pretend that you + +were part of a department, +the STEM department. + +Call it whatever field you want. + +And there is a proposal +that your department + +should commit funds +to train professors + +and develop resources, +the resources + +necessary for the adoption and +ongoing use of active learning + +techniques in all courses. + +And the target date is 2017. + +You've got a year to +get all courses up + +to speed with active +learning stuff introduced + +into these classes and with +a plan for how to do that. + +So what I'm going to do is I'm +going to just count off one, + +two, three, one, two, three. + +And I'm going to ask +you to form a group. + +If you're a one, go +with the one group. + +Two go with the two group. + +A three go with the three group. + +And you're going to +have to physically move. + +So just remember your number. + +One. + +AUDIENCE: Two. + +AUDIENCE: Three. + +AUDIENCE: One. + +AUDIENCE: Two. + +AUDIENCE: Three. + +AUDIENCE: One. + +AUDIENCE: Two. + +AUDIENCE: Three. + +AUDIENCE: One. + +AUDIENCE: Two. + +AUDIENCE: Three. + +AUDIENCE: One. + +JANET RANKIN: It doesn't matter +that they're not the same size. + +Can we get all the ones, let's +say all the ones up here? + +All the twos here. + +And all the threes there. + +And I'll tell you what +to do in just a sec. + +So if you're group +number one, you + +have to adopt the +position that you are pro. + +You are going to push for the +adoption of this resolution. + +And you have to come up +with a set of arguments + +and a set of reasons +why it's a good thing. + +I don't care what +you think personally. + +I don't care if you think +active learning is the worst + +idea ever. + +For the purposes +of this debate, you + +need to pretend you're +totally into it. + +And you need to come up with +some good arguments why. + +Two are against it. + +Again, I don't care how +you feel personally. + +But come up with some +good solid arguments + +why you should not do this. + +AUDIENCE: We are against it? + +JANET RANKIN: Against, +you do you not want it. + +No. + +Group number three, you +got a little bit of time. + +But get to know each other. + +And you're going to +hear the arguments. + +You're going to hear a case +presented by the pro people, + +the con people. + +And then you are going +to deliberate and decide + +what's going to happen +in your department. + +You guys are the deciders. + +It's an American political joke. + +But we'll let that go. + +And you guys get this +lovely microphone. + +So I'm going to give +you 10 minutes for this. + +So be ready to share your views. + +You've got about, +maybe, two or three + +minutes of a spiel of proof. + +And then we'll do one +exchange of debate. + +And then the +deciders will decide. + +[SIDE CONVERSATIONS] + +JANET RANKIN: I'm going to ask +someone from each of the groups + +to make a statement +that puts forth the side + +that you're supposed to defend, +if that is the side you're + +supposed to defend. + +So we'll start with the pros. + +So someone from your +group ready to talk pros? + +All right, Michelle. + +AUDIENCE: So we are +pro active learning. + +And part of the +basis for thinking + +that active learning's +important is + +that we believe that +without active learning, + +the professor usually +just resorts to lecturing. + +And we think that lectures +are not effective. + +Students don't learn +simply because the material + +is presented to them. + +Lecturing wastes +resources, because you + +could be lecturing to 1,000. + +But only 15 students +may be reached. + +And if you use active +learning instead of lecturing, + +it can make sure the students +are paying attention. + +You can check that +they're understanding. + +You can know what +they are getting + +and what they're not getting. + +We also feel that active +learning is a life skill. + +And that if students learn +to learn by do things + +and they learn by +talking to each other + +and by going through a +process and solving problems, + +that they can take this skill to +outside of the classroom later + +in society. + +Then that the society +that you have students + +who are used to +being active learners + +and who know how to +solve problems that way. + +And we also think that the +end, the big point that we have + +is that you remember +things that you use. + +If you learn something, +if it goes in one ear + +and out the other, if you +don't actually use it, + +you're not going to remember it. + +If you're not forced to +actually work through a problem + +and really think about it +and use it in a classroom, + +that you're much less +likely to actually hold on + +to that information. + +So these are all +reasons why we think + +that we should promote active +learning in our department. + +JANET RANKIN: OK, +thank you very much. + +The con, or I guess I +should say the not whatever. + +Anyway, group two. + +AUDIENCE: Do you want to do it? + +AUDIENCE: OK. + +We start with a basic question. + +The question is, why do we +want to change what is working? + +We are training our students. + +They are getting job. + +The professor are doing well. + +They are collecting grants. + +The original [INAUDIBLE] is OK. + +So why do you want to +change what is working? + +So that is the first question. + +Now the first thing is that, +if you want to go about this, + +it's going to consume +a lot of money. + +It's going to take +a lot of money. + +And then it cuts +into your funds. + +The one funds for other +such, want to buy equipment + +for the laboratory, want +to go hire scientists, + +want to go hire post doc. + +So why do we want to change? + +Where do we get these funds? + +We divert funds for the +training of professors. + +And they're going to be +little bit of no funds for all + +this such work. + +And secondly, the efforts +to train professors + +is likely to be very huge. + +Professors are used to +this method of teaching. + +And as you saw, they +will not want to change. + +There's going to be a lot +of time changing them. + +And we're not even sure, +if we try to change them, + +whether they're going to be able +to do it at the end of the day. + +Thirdly, we are not sure that +the stakeholder would be happy. + +What about the alumni +that are very much + +used to the method of teaching? + +What about the parents? + +are they now going +to go against us? + +Will they not see that +the professor no longer, + +just come to the class, give +them group work like this + +without teaching, +without writing? + +Then the professor is +no longer teaching. + +And they are just going +to collect their salary. + +And then, there's +not to be constrained + +on time to cover syllabus. + +When I saw I spend +a lot of money + +being in group work, +individual, or this and that. + +So how do you complete +your syllabus? + +You have about 20 topics +to cover this semester. + +And by the time you +start active learning, + +how are going you cover +about 50% of them? + +Then you push all of +that up [INAUDIBLE]. + +So it's not going to work. + +We should just drop the idea. + +What have we value +very last class? + +You have your class of 500. + +How do you want active +learning to be effective? + +How do you want to treat them? + +It's good here, because we are +just about 15 or less than 20. + +By the time you have +500 students in a class, + +it's going to be very +difficult for you + +to have active learning, +difficult for the professor + +to control classes, +and of course, + +difficult for you to really +get something concrete out + +of the whole thing. + +So my final guys and professors, +I think it's not necessary. + +the. + +System is working. + +Let it continue +to work this way. + +Thank you. + +JANET RANKIN: So now +what I'm going to do + +is I'm going to +let each group ask + +one question or a set +of clustered questions + +to the other group. + +The other group can answer them. + +And then the deciders can +ask a couple questions. + +And then we'll let +them deliberate. + +So group number one, like to ask +some questions to group number + +two or make some comments? + +Go ahead. + +AUDIENCE: Yeah, I +listened to you speak. + +And I want to ask you. + +You are saying that +the system is changing. + +It is changing because the +status quo isn't delivering. + +So that is why we are +adopting active learning. + +And this is proven from +a research perspective. + +There is actually letting more +students learn more materials + +faster and more effectively. + +So what do you think about that? + +AUDIENCE: I'll +answer it by saying + +the different research shows us +that the student that is good + +is good. + +[INAUDIBLE] + +So why can't we just concentrate +on getting those students? + +And what your presentation +didn't say about funds, + +was the whole idea is +to fund the proposal. + +And if we divert funds +to this new program, + +and that's a very big issue. + +You have to concentrate +on the question that + +is the diversion of +funds away from research. + +So if we can get the new +students and they can learn + +by [INAUDIBLE], and +it's working great-- + +go ahead. + +AUDIENCE: So you +want to throw away + +the baby with the bath water? + +If you have 20 +students in a class, + +and you have five +active learners, + +and then you want to +discover 15 that wouldn't. + +This program is geared towards +each one of the students + +in the class to participate. + +And I think it's +more cost effective. + +If you could get +all the 20 students + +to learn and to +learn actively, I + +think that would pay itself +off at the end of the-- + +AUDIENCE: No, the +problem there is that you + +have to face the proposal. + +This is 2017. + +It's a lot of change +in a very short time. + +The proposal itself +is already against-- + +AUDIENCE: Our department +could be three people big. + +We don't know how much +the department is. + +[INTERPOSING VOICES] + +AUDIENCE: But then +the issue there + +is that you're going +to retrain professors. + +Professors are really +stuck in their ways. + +And you spend all this money. + +And it's very short time. + +There's lots of +people from the labs, + +and money from the labs +in this very short time + +to train them on +something we don't + +know if they're +ready to buy into it. + +AUDIENCE: So I think +your assumption is that-- + +you're like, we're deferring +funds from labs and resort. + +But you never once said you're +diverting funds from anything + +related to the students. + +You're thinking of it from +the professor perspective. + +But really professors are +here to teach their students. + +And you're like, oh, +we're taking money away + +from the research, +from the lab equipment, + +from all these +different things that + +sound great to the professor +but have literally nothing + +to do with the students +learning experience + +or the student's +experience on campus. + +And from the +student's perspective, + +that's really frustrating, when +that's all the professors care + +about. + +And that's what +makes a difference + +between a good professor +and a crap professor + +is one who cares. + +And I think, if you want +a professor to care, + +oftentimes they're willing +to make the effort that + +is needed to change +their teaching style + +or do whatever it is +that's necessary to have + +their kid interested and +engaged in the same material + +that this professor loves. + +So you keep talking +about diverting funds. + +But you never once mentioned +diverting these funds + +away from this one +teaching initiative + +to a different +teaching initiative. + +So just keep that in mind . + +AUDIENCE: So the +problem is that when + +we are looking at the proposal +itself, the time, 2017, this + +is already the end of 2015. + +So that means you +are going to do this, + +by 2017, that means you're +going to do it by 2016. + +We're not against active +learning in the [INAUDIBLE]. + +[LAUGHTER] + +[INTERPOSING VOICES] + +AUDIENCE: --the proposal. + +We are against-- we +need these two group + +and against this proposal. + +So for this proposal, we +are against this proposal, + +because you know how +much it's about the funds + +and the resources. + +And that is why we are +against the proposal. + +And also you pick +whatever [INAUDIBLE], + +we're not even sure that +it is going to work. + +JANET RANKIN: I'm going to +take, because you guys actually + +did ask a question, so I'm +going to count that to you + +Did you have another +separate one? + +AJ, you look like you +might have some questions. + +AUDIENCE: Yeah actually +I was just curious, + +so if this initiative +is really great, + +it looks like a lot +of this research + +has been done since '80s. + +Why isn't it adopted? + +Why are we having this +conversation now in 2015? + +AUDIENCE: I think +we should look back + +at this issue of the lecturing +system that we are using now. + +It's static. + +When there was no +printing, lecturers then, + +they get the material. + +They reach the students. + +So lecturing is a Latin +word that means reading. + +Now since then, now +we are printing. + +We have information +readily available + +that people can get on at +their home and their own + +and develop to something. + +Too So there is a need for +us to change to a new system, + +because the old system that +more facilitated lecturing has + +changed. + +So then we have to change. + +JANET RANKIN: I'm +going to turn it over + +to the deciders who +now have to discuss. + +They've been resting +for many minutes. + +So now they have to. + +So you have questions +for each of the groups? + +AUDIENCE: Yeah. + +AUDIENCE: Yeah, thank you. + +Great arguments on both sides. + +I found it interesting, when +you talked about the larger + +classes, so my first +question is for this group. + +So how would active learning +apply to a large class? + +The proposal is that +it's for all courses. + +And so are there courses where +this doesn't lend itself to? + +AUDIENCE: Even in the classes +with 700, 800 students here, + +they still do active learning +for the freshmen, i.e. + +Clicker questions. + +Oftentimes professors have +to talk to your partners. + +So they'll pose a question. + +Everyone will click +on their answer. + +And then they'll be +like, now go back + +and talk to the person +sitting next to you. + +And then you'll vote +again in two minutes. + +So I think that's just one +example of how you can engage + +a class of a lot of students. + +AUDIENCE: And to add +to that, actually it's + +also been found out that when +peers speak to themselves, + +they even learn the +material better than when + +the expert, who may have lost +touch to what it could be + +like to learn from a +student's perspective. + +So peers speak to themselves +and teach themselves even faster + +than the expert who +is in front of them. + +AUDIENCE: Yeah I have comment +for the against group. + +You mentioned that you +don't require to create + +or active learning, because +some students are very smart. + +They get it right. + +But don't you think +that education + +is a right of every child? + +And they deserve to +have a good shot at it. + +So why do you want to pull +one child out of here, + +because he's not smart enough? + +AUDIENCE: I just +to answer, I think + +we are pushing for +the best education. + +We believe that is +the traditional way. + +We think that active +learning can happen + +outside of the classroom. + +This is the way it's +worked for 300 plus years + +over at Harvard, one of +the best universities, MIT + +for 100 plus years. + +We think that +essentially it's working. + +And the reason we're having +this conversation right + +now is because it has worked. + +So we want to +continue that legacy. + +We think that every system +is going to have problems. + +And if you analyze any system, +you're going to find issues. + +And there are certainly +some smaller inefficiencies + +within the lecture. + +But by and large, it's trusted. + +And it works. + +AUDIENCE: I want to +add on what adding. + +So I think we are not pushing +those less smart kids away, + +because they can actually +learn from each other outside + +of class. + +We just want to say +that doing the lecture + +is more efficient if the +professor lecturing at them, + +giving all the information. + +As a footnote to that-- sorry-- + +if professors come to the +class and just give theory + +and go away, and the +smart kids get it, + +then how do you measure the +professor's performance? + +How do you think +about, say, something + +like students information +on educational quality? + +How do you measure that? + +AUDIENCE: You don't +really need the professor + +to be extremely active and do +active teaching in the class. + +The full student can +actually get what they need. + +You have a bunch of homeworks. + +You have a bunch of test +questions, exam questions, + +that student, whether +they like it or not, + +they will surely be forced +to read those things. + +And by the time they come +back, they come back learning. + +Lot of graduate from MIT, +they are l really doing well. + +About 25% start up +their own business. + +Probably like 70% get +jobs when they finish. + +What are you talking about? + +The system is working. + +And That's what we're saying. + +And their value is a great. + +The evaluation is +done on the type + +of textbook, the +mode of lecture, + +the [INAUDIBLE] lecture. + +So these are the things +that I try to evaluate + +in the evaluation process. + +And it has been great. + +And we want it to continue. + +AUDIENCE: So we addressed +the measuring impact. + +And that goes for both. + +But for the active +learning, how do we + +quantify how much +active learning needs + +to go into these different +classrooms in the department? + +So how will we ensure +the appropriate amount + +has been implemented in +different classrooms? + +Basically, how much +active learning + +needs to go into a +classroom to create change + +or to strengthen our +student learning? + +AUDIENCE: How much +has to go in or how + +you're going to make sure that +the professors are doing it? + +AUDIENCE: Both, I +guess, is the question. + +If there's a professor that's +more on the lecture side + +that might throw one thing pair +share in and call it a day. + +So how do we ensure the +appropriate active learning + +techniques and the quantity +are there for the classrooms? + +AUDIENCE: I think we'd have +to go back to the research + +and see how much, whether +it's 30% of the time needs + +to be spent on active +learning activities, + +or to see what has been proven, +because active learning has + +been proven to be effective. + +But we would have to +go back and make sure + +that we set a standard that, +if it is 30% of the time + +or 70% of the time. + +And I think oversight +from the department + +would be important, in that the +leadership in the department + +will have to sit in on classes. + +And as part of the +training of the professors, + +there has to be training. + +But then there has to be someone +to observe them in the class, + +give feedback. + +The training has to be ongoing. + +It's not just a three +hour seminar on this + +is with active learning is. + +And this is what you should do. + +I think it's going +to be a long term + +investment in the +professor training + +that someone's going to have +to check up and give them + +feedback. + +And then they can +adjust from there. + +JANET RANKIN: I'm sure that +we could [INAUDIBLE] all day. + +But I'm going to give the +deciders two and a half + +minutes, three minutes, +to talk to each other + +and come up with a decision. + +All right, the +committee has met. + +And now they're going +to determine your fate + +in this department. + +AUDIENCE: Does this mic work? + +Is this on? + +Do I need to use the mic. + +You can hear? + +Well thank you again +for your arguments. + +Certainly the panel felt +that the pro arguments + +in terms of the benefits of +active learning are great. + +And we definitely support that. + +However, given the time +frame, and this proposal + +is very aggressive, it would +be extremely disruptive. + +Also the amount of +funds that we think + +that it would take +to implement this + +would be very high without any +proven way to measure success. + +So what we are willing +to do is commit funds + +to a pilot program, +where we can then + +measure what the success +will be and then make + +it a decision next year +as to whether or not + +we invest for the rest +of the departments. + +[INTERPOSING VOICES] + +JANET RANKIN: So I hope you +found this exercise useful. + +I just want to debrief +on the exercise itself, + +why we bothered to do it. + +It took probably 45 +minutes of time to do it. + +But I made a decision +that would be useful. + +So what did we get +out of this exercise? + +What was the point? + +AUDIENCE: Whether you think +that's it's worth it or not, + +it's really important time. + +Also, it seems +this confrontation + +is happening a lot in the +department, especially + +[INAUDIBLE] as they go +through the program. + +I assumed this test would +be debated quite a bit, + +internally and externally. + +JANET RANKIN: Other +reasons we engaged in this? + +AUDIENCE: I think +it gives everybody + +the opportunity to think deeply +about the subject matter. + +And it also, even if you are +against or for something, + +you have to have +a deeper knowledge + +to be able to bring out the +good points, certain issues that + +might actually make +see [INAUDIBLE]. + +JANET RANKIN: [INAUDIBLE], +you want to add to that? + +AUDIENCE: The topic +is active learning. + +And what we just demonstrated +is active learning in practice. + +JANET RANKIN: Yes, exactly. + +And the idea to +Gordon's point, the idea + +that it can be very, very +useful for you to have students + +take an arbitrary +position and argue it, + +because they will +learn things, they + +will think about things, +that they would not + +have thought about otherwise. + +And it's usually not a good +idea to say OK everybody that + +thinks this, go over here. + +Everybody that thinks +this, go over here, + +because all that +does is reinforce + +what people think already. + +And maybe it's not +completely correct. + +So this is often a +very good technique, + +when there's two clear +viewpoints or two clear sides. + +And you want students to +really engage with that. + +And exactly, we could +have had a discussion. + +Or I could have had +PowerPoint slides that + +said, here are the good things. + +Here are the pros with active +learning, bum, bum, bum, bum, + +bum. + +Here are the cons of active +learning, bum, bum, bum, bum, + +bum. + +And that would've taken-- + +just to come out of my +neutral position here-- + +that would have taken +probably four minutes. + +Instead we took 35 +or so, 40 minutes. + +But I think you probably +engaged with some + +of the ideas and +concepts a little bit + +deeper, because you had to +come up with it yourself. + +So yes, all those reasons. + +And it does come up often. + +People are discussing it. + +And it's not so clear cut. + +There's not a right answer. + +And you're going to want to say, +OK, well we'll do it by 2019. + +Or we'll do it. + +But we won't do that. + +There's going to be deals and +all those kinds of things. + +And that's OK. + +It's OK that there's +not a right answer. + +But that was the point +of this exercise. + +So that served as our +discussion for active learning. + +But you guys did it. + +I didn't do anything. + +AUDIENCE: And that +buttresses the point + +that active learning +is the way to go. + +JANET RANKIN: Thank you. + +Yes, this is very meta. + +This is very meta here. + +Yeah and I do have to +feel a little bit bad + +when you're like, what? + +Then we're going +to do all the work. + +And the lecturer's just going +to sit back and not do anything. + +I took it personally. + +But no, no, it's OK. + +One thing I wanted +to bring up is + +if you haven't read the +Scott Freeman article, + +it's in the reading +list for today. + +It shows-- let me +just bump to it-- + +it shows essentially +these results. + +He did a meta analysis of 225 +studies on active learning + +or on classes that that +used active learning. + +And they showed a 12% +decrease in the failure rate + +in classes that used +active learning. + +And so I was telling the +pro group that what say + +in the paper is that if it had +been a clinical drug trial, + +and 12% of the people on the +drug were having a better + +outcome than the people on the +placebo, they would have had-- + +or the people on the control-- + +they would have had +to stop the trial + +and give everyone the drug. + +So in the sense of why +we're still lecturing, + +that's to me one of the +biggest compelling reasons + +for why we should be doing +more active learning. + +12% of the students are going +to pass the class, on average, + +normalized. + +And they actually considered +both experienced lecturers, who + +were just lecturing, +people that were considered + +to be good lecturers +that were just lecturing, + +as well as graduate students +who were first time teachers + +but were using active learning. + +So they looked at +all sorts of-- they + +mixed up all sorts of outcomes. + +And active learning appears to, +the data's pretty conclusive. + +And this isn't the only +study that shows it. + +So there are definitely issues. + +There are definitely +implementation issues. + +They're definitely +sticking points. + +But it's something that +I think we can't ignore. + +AUDIENCE: I just want +to add that it's not + +only that we have 12% +decrease in the failure rate. + +We also have big shifts in +the letter grade students get. + +For instance, more people +shift from grade C to grade B + +or from B to A. And B +to see a test like that. + +So that's really +significant also. + +JANET RANKIN: So I just want +not have learning outcomes. + +But I did want to have the +discussion before I even + +introduced them. + +So I think you'll +be able to explain + +the impact of active learning +exercises in the classroom. + +You've already +started to do that. + +And then you'll be able +to identify and develop + +active learning exercises +that you'll want to use. + +And you'll be able to think +about how you might use them. + +I think, pretty attainable +learning outcomes. + +I'm going to show +the slide a lot + +throughout the rest of the time. + +But remember, it's +constructive alignment. + +We've seen this diagram before. + +But the beauty of some of these +active learning techniques + +is that their +formative assessments + +of students' understanding, +of students' learning. + +And so they are +actually activities + +that happen in the class. + +But they're also measures, +informative, formative measures + +of whether students +are learning or not. + +So if somebody had come up with +a really terrible argument, + +or it was clear that nobody +had read any of the papers + +on the active learning +research, then I + +would know that +from this debate. + +I know what you've read +and what you haven't read, + +and what you're +thinking about and what + +you're not thinking about. + +And I get a good sense for +whether or not it you know it + +and how much and how +well you know it. + +And so do you. + +And we'll see that +a little bit more + +in these other situations, +where if you get a clicker + +question wrong or you get a +multiple choice question wrong + +or that you can't participate +in the lightning round, + +then you know that you've +got to step up to the plate. + +Or you need to try +something different. + +Or you're not really getting it. + +So you get information. + +The learner gets information. + +And the teacher +gets information. + +AUDIENCE: I just thought +that was really powerful + +in the readings, as well. + +They mentioned that, +that students who, + +when they get in +the group sections, + +if it's clear they really are +getting a lot of things wrong, + +they know they need to step up. + +And that's in a different way, I +think, than getting a bad grade + +on a paper. + +And you know the average +distribution or whatever. + +Or the professor +says you're wrong. + +But when you know that the +people sitting right next + +to you are getting it and you're +not, that really, I think, + +will push the student +forward to do something. + +JANET RANKIN: It's +news you can use. + +It's information. + +And then you're not +being penalized. + +You're not in trouble. + +It's not affecting +your grade if you + +act on it, if you take the +information and use it. + +So that's why, I think +that's the beauty of it. + +There are many, many +active learning techniques. + +And if you looked at the +website from University + +of South Florida +has just, I think, + +it's close to 200 techniques +for what you might do. + +I'm doing a bit of a-- + +I call it the foie gras method. + +You know how they +make foie gras? + +They force feed the goose. + +So I'm going to give a lot. + +And we're going to do a lot +of different active learning + +things in this session. + +It's a little bit comical. + +I know it's kind of +funny how many we're + +trying to cram into two hours. + +But I'm going to try to do that. + +So we'll do some of these. + +And we can talk about any +one of them in particular. + +But a nice one to get students +in the frame of your class + +is to they come in. + +And they have five minutes +before you do anything + +to write down what they thought +was the most interesting part + +of the reading or answer +a certain question related + +to the reading or solve a +problem or whatever it is. + +You give them a prompt. + +You sit down. + +You focus them. + +And then they're off. + +I do want to just focus on the +word active for just a second. + +It may help you to think +about active and interactive + +learning. + +There's all sorts of +ways to chop it up. + +And at some level, +it's semantics. + +But at some level, it isn't. + +So students can be +active if they're + +sitting by themselves +thinking about something + +and writing something +down or solving a problem. + +That is active learning. + +They don't have to be +talking to each other. + +You can do active learning +in a class of 3,000 people. + +Stop and think. + +Answer this question. + +That's active learning. + +That's way more than +happens in a lot of classes. + +Interactive learning generally +implies that students + +are talking to each other. + +That's the most general +categorizations you can get, + +active, interactive. + +So we're going to +do a bunch of stuff + +with clickers or +plickers, these things. + +But there's some other +techniques you can do. + +You can put up a +graph or an image. + +And you could say, +OK, somebody come up + +and show me the green +boundary in this picture. + +Show me a triple junction. + +Show me where the building, the +crack in the building started. + +Show me whatever. + +And you pass the pointer. + +And then you have +the student who + +has the pointer come up +with another question + +and pass it to somebody else. + +So that's another nice technique +that takes the responsibility + +off of the teacher. + +And so you're not +picking on students. + +We've been doing mud +cards, think, pair, share. + +We're going to do +a lightning round. + +I'll talk a little bit +more about jigsaw later. + +And if time allows, +I'll show you + +a demo I did on diffusion using +the students as the atoms. + +Sometimes if you're trying +to ease in active learning, + +slowly into your class-- you +don't want to do too much-- + +you want to think about +the short time things that + +don't require huge disruptions. + +If you want to go back +to your seats, you can. + +Maybe I should let +you guys do that. + +So you know what we'll do? + +While they're +taking a break, I'm + +going to demo the beach ball. + +So this is nice. + +This is the beach +ball technique. + +So when you catch +the ball, I'd like + +you to tell me if you've +had any experiences + +with active learning in +classes that you've taken. + +And you can't count this one. + +AUDIENCE: I had active learning +in my electricity and magnetism + +class. + +And that was called TEAL. + +And it's very polarized. + +The people for and against +it, especially the students. + +So they basically +tables of nine. + +And then within that table, +you had groups of three. + +And each of those would be +a problem solving group. + +So you'd have four problems +to solve per two hour class + +period. + +And that would be going +up to the board look + +and doing it by themselves. + +And then the teacher at the +end would reveal the answers + +and tell us how +to go through it. + +And, for my group at +least, there was always-- + +or my table-- + +there was always +this one person who + +would write every single time-- + +JANET RANKIN: 3,000 People. + +Stop and think. + +Answer this question. + +That's active learning. + +That's way more that +happens in a lot of classes. + +Interactive learning generally +implies that students + +are talking to each other. + +And that's the most +general categorizations + +you can get active, interactive. + +So we're going to do a bunch +of stuff with clickers, + +or plickers, these things. + +But there's some other +techniques you can do. + +You can put up a +graph or an image. + +And you could say, +OK, somebody come up + +and show me the green +boundary in this picture. + +Show me a triple junction. + +Show me where the building, the +crack in the building started. + +Show me whatever. + +And you pass the pointer. + +And then you have +the student who + +has the pointer come up +with another question + +and pass it to somebody else. + +So that's another nice technique +that takes the responsibility + +off of the teacher. + +And so you're not +picking on students. + +We've been doing mud +cards, think, pair, share. + +We're going to do +a lightning round. + +I'll talk a little bit +more about jigsaw later on. + +And if time allows, +I'll show you + +a demo I did on diffusion using +the students as the atoms. + +Sometimes if you're trying +to ease in active learning, + +slowly into your class-- + +you don't want to do too much-- + +you want to think about +the short time things that + +don't require huge disruptions. + +If you want to go back +to your seats, you can. + +Maybe I should let +you guys do that. + +So you know what we'll do? + +While they're +taking a break, I'm + +going to demo the beach ball. + +So this is nice. + +This is the beach +ball technique. + +So when you catch +the ball, I'd like + +you to tell me if you've +had any experiences + +with active learning in +classes that you've taken. + +And you can't count this one. + +AUDIENCE: I had active learning +in my electricity and magnetism + +class. + +And that was called TEAL. + +It's very polarized, the people +for and against it, especially + +the students. + +So we basically +had tables of nine. + +And then within that table, +we had groups of three. + +And each of those would be +a problem solving group. + +So you'd have four problems +to solve per two hour class + +period. + +And that would be +going up to the board + +and doing it by themselves. +and then the teacher at the end + +would reveal the +answer and telling us + +how to go through it. + +And for my group at least-- + +or my table-- there +was always this one who + +would write every single time. + +And I feel like that detracted +from active learning. + +I think it worked +better for other people. + +JANET RANKIN: It's +definitely polarized. + +Students really are not-- + +I think we talked a +little bit about this + +when we did some of +the learning theories-- + +but students really are +polarized about whether they + +like it or not. + +The data that there's been +some pretty good analysis + +of learning, measuring +how much students learn, + +and then how much they retain +and all that kind of stuff. + +And when you go +through that, students + +seem to learn more and retain +more in the active learning + +format, even though they +really at least half of them + +don't like it at all. + +So it's an +interesting commentary + +That's a good great story. + +So why don't you +give the ball a toss? + +There you go. + +No, you have to +answer a question. + +Have you ever experienced +active learning + +in a classroom +besides this class? + +And how did it work or not work? + +AUDIENCE: I would +say yes to that. + +It's definitely the traditional +method, sitting in front, + +face to face lecture. + +JANET RANKIN: Fair enough. + +Give a toss, toss to anyone. + +Are we going to get the +same answer from all of you? + +If it's just-- + +AUDIENCE: Is it +the same question? + +JANET RANKIN: Yeah, +same question. + +AUDIENCE: Yeah, I have. + +Because I recently +studied in Sweden. + +And that's the way, most +of the time that way, + +they teach in Sweden. + +So for some classes, generally +in higher level classes, + +according with d-level classes, +they use active learning. + +JANET RANKIN: Great and +students buy into it? + +They're OK with it? + +They work at it? + +AUDIENCE: Culturally, +they tend to veer + +towards active learning. + +JANET RANKIN: And that's +a very interesting point, + +the idea that it can +be a cultural thing. + +If everybody else is doing +it, or it's expected, + +then that's what you do right. + +So some of these changes, +there's an incubation period + +before they actually take off +and they're widely accepted. + +AUDIENCE: In fact +in Denmark, I think + +that's the only way they each. + +JANET RANKIN: It's +pretty active. + +I have a colleague +who's in, or friend + +who works at the +University of Copenhagen, + +and all new faculty have to take +a yearlong course on teaching, + +no matter what department, +physics, math, a year long, + +the faculty. + +And here you could never force +the faculty to do anything. + +So it's pretty +interesting that they've + +been doing it for so long. + +AUDIENCE: I have a +question about that. + +Is it the way that professors, +their role as actual teachers + +is viewed? + +[INAUDIBLE] + +But seriously, +people [INAUDIBLE] + +or something, I think definitely +trying to enforce a teaching + +class would be a +lot more receptive + +than if you tried to enforce +that here, where teaching + +isn't necessarily the focus. + +JANET RANKIN: But there, it's +a good research university. + +But on the teaching +side, that's the norm. + +That's the expectation. + +AUDIENCE: But what +about requiring-- + +I know it's hard when +you have professors + +that have been +doing what they're + +doing for 25, 30, 40 years. + +It's hard to get them +to adopt new techniques. + +But I think that requiring +things-- the faculty + +that you can require things +of are the new faculty, who + +have no power yet. + +JANET RANKIN: Yes and no. + +If the tenured system, the +requirements for tenure + +don't change, then asking +them to take on new-- oh, + +you guys should try +active learning. + +Revamp this course. + +And then they don't get tenure. + +So it really has to be +a whole systemic change, + +where the department buys in. + +The school buys in. + +The university buys +in and says, OK, these + +are the criteria for tenure. + +And in that is you have +to use active learning. + +Or you have to-- + +that's where it would +have to get change. + +Otherwise you +can't expect people + +that aren't tenured to do it. + +You shouldn't. + +Let's give the +ball one more toss. + +AUDIENCE: So it's +been a long time + +since I've been in a classroom. + +I would say, in a +regular classroom, + +I don't that I've +been in a class that + +does active learning. + +But I have taken courses +that are largely lab courses, + +like a mouse embryology +course, where + +you have 15 minutes of lecture. + +And then you go into +the lab And you do it. + +And the professor will +walk around and help you + +with the technique. + +You're actually +there with the mice. + +And you're actually +doing something. + +So does that count? + +JANET RANKIN: Lab courses +can be their own genre. + +But there has been +this movement to take + +that's a little bit of what TEAL +does, at a more simple level. + +And there's a little +bit of lecture. + +And then students are supposed +to answer some questions + +or do something. + +And then they come +back together. + +And Studio Labs at WPI +has that same format, + +where the classrooms are +built with lab benches. + +And students sit at lab +benches and see a lecture. + +And then they do +some experiments. + +They're mini experiments. + +It's not whole mouse dissection. + +But they do a mini experiment. + +And then they report back. + +And there's an +interchange like that. + +So there are some +blending of the two. + +Often what people do +in labs is different. + +And usually a good +lab is fabulous. + +A good lab is fabulous, which +is another argument for why + +active learning is +good, because everybody + +thinks back about, oh, that +lab course was so great. + +I learned so much +and did so much. + +And yet that's the lab course. + +And then we have the lecture. + +So it's an interesting comment. + +So that was the beach ball. + +And you see you +guys got to throw + +the ball at other students. + +So I didn't have +to pick on every-- + +I didn't have to call on +people or pick on people. + +I had a little demo here +about why it's important, + +just if you ask a question +or you ask students + +if there are any questions +or what questions they have. + +And that's generally +a better phrase. + +What questions do you have? + +It's more welcoming, opposed to +saying OK, who's stupid enough. + +Who's not following me? + +Say, OK, what are the questions? + +It's a more welcoming phrase. + +But the idea of waiting. + +So here, if I click +on this little guy, + +you should hear 30 +seconds of music. + +So imagine you ask a question, +30 seconds for people + +to think about it and +formulate an answer. + +This is what 30 seconds +feels like of dead time. + +Well, there'll be music. + +[MUSIC PLAYING] + +That's not part of it. + +So did that feel +like a long time? + +I know we had a +little break there. + +But that feels like a lot. + +Especially when you're +standing up here, + +it feels like a long time. + +But 30 seconds, give +them 30 seconds. + +The point is, if you want +to give students 30 seconds, + +you're going to have to time it. + +You totally have to time it, +because you will not estimate + +30 seconds effectively. + +You will totally +underestimate it. + +And then another +technique that you + +can piggyback on that is +saying, OK, take 30 seconds. + +I'm not going to take any +answers for 30 seconds. + +So you may have an +answer right away. + +But I don't want to +hear it for 30 seconds, + +because there's always +that guy in the front. + +I had this guy in my +high school math class. + +And he used to sit on his-- +this little short guy-- + +and he used to sit on +his foot on the chair. + +He's on his chair. + +And he's sitting on his foot. + +And he had his hand like this. + +And he was in the front row. + +And whenever the teacher asked +the question, he would go. + +And he would come up off of it. + +And so he was always the guy +that answer the questions. + +But that left some of us +who took a little more time + +not having the +opportunity, kind of + +like having the one person write +all the time in the TEAL group. + +So that's a good way +to go about that. + +We talk a little bit about +using clicker questions + +to solicit feedback. + +And we've used the +plickers in this class. + +We'll use them again. + +You can get dedicated +clickers, these dedicated punch + +in things. + +They use them for TEAL, I think. + +Students may have +to purchase them. + +That may cost money. + +The department may +have to purchase them. + +That's another source of money. + +AUDIENCE: They make +us buy everything. + +JANET RANKIN: So when I +was at Brown, actually, + +the department would buy them. + +And they'd leave +them in the library. + +And then you could check them +out with your student ID. + +And then you got that. + +So you got it for the semester. + +But it was linked to your ID. + +And if you didn't bring it +back, they'd charge you for it. + +But that's another way to do +it, a fairer way to do it. + +We'll look at something +called Socrative later on. + +I'll use it later on. + +But it's a text. + +It's an online format. + +So students need a +smartphone or a laptop. + +But they don't need +a separate clicker. + +There are issues with that, +because not everybody is + +going to have a smartphone. + +And are you biasing your class +against people that don't + +happen to have the technology? + +This is why I like +plickers, because you + +don't need to buy anything. + +I give you the card. + +And I need to have +the smartphone. + +But you don't. + +And then you could +always use index cards + +or do the whole, +put one finger up + +if you think it's A and two +if it's B and three if it's + +C. That gets a little +tough in a bigger class, + +because it's hard to see. + +It's hard to count. + +I like the fact that +the clickers, plickers, + +and the Socrative +or Poll Everywhere + +give you a histogram. + +So you get a really quick +idea about who's getting it + +and who isn't getting it. + +So we're going to do +a couple of these. + +Remember-- this is from +the label of the free body + +diagram-- that these +misconceptions always + +linger in a lecture class. + +We talked about this free +diagram the other day. + +So let's just try this one here, +give you another little warm up + +on the picker's. + +So you have the card. + +And I'm just going to ask +you to look at the question. + +And when you're ready to +answer, just hold up your card. + +And if you can keep your +finger away from the pattern, + +that would be great, because +it makes it hard to read it. + +And then however you want to-- + +AUDIENCE: Does this work +for larger classrooms? + +JANET RANKIN: It does. + +I have a colleague +who uses it at Brown. + +And he just started +teaching this semester. + +And he showed me his-- + +or a friend-- he +showed me his plickers. + +And he printed them +out on 8 by 10, + +like a sheet of +paper, cardstock. + +And they're enormous. + +They're like this big. + +AUDIENCE: How do you +not get [INAUDIBLE]? + +Well Well they have +to hold them up. + +You have to. + +And you can walk +around a little bit. + +But I'll show you this. + +So I have the histogram. + +And I measured everybody. + +So now I know what you +think about this question. + +I know who's got it right. + +I don't know who's got it right. + +But I know that most of you +have chosen the correct answer. + +But there were a +few of you picked up + +one of the other answers. + +And so now I know that it's a +non-trivial number of you that + +picked an incorrect answer. + +So now I know exactly +what I need to do. + +It's given me incredibly +good information + +that there is some +out there that + +have a pretty strong +misunderstanding + +of the literature. + +And that's that +some of you picked + +A. There's a lot of data to +support that active learning, + +active technique supports +student learning. + +I call your attention +to the Freeman paper + +that's in the reading for +today, also to the [? Haik ?] + +article, which was referenced. + +So those are two of the +more compelling readings. + +But if you go through, you'll +see quite a few studies + +that unambiguously show that +active learning has an impact. + +So the incorrect answer is that +it always involves group work. + +That's not true. + +It doesn't always involve work. + +As we said, you could +just ask students + +to sit and think and then do +something with their thoughts. + +And that would be active. + +So Rachel, you're smiling. + +Is there a-- + +OK. + +AUDIENCE: Sometimes my +face just does that. + +JANET RANKIN: I didn't +know whether it was a smirk + +or whatever. + +And did I show you +what this looks like? + +So you can see with the +histogram looks like. + +I did? + +[INTERPOSING VOICES] + +You weren't here, +though, when I did. + +The time I used it before. + +I'll show you offline. + +So the histogram is +really, really useful. + +So it really can ferret +out some misunderstanding. + +We don't have to go +through all these. + +But this is another way to +check for misunderstanding. + +I can ask this kind of question. + +It's a concept question. + +It's a conceptual question. + +And then I can ask +you to pick an answer. + +And then I can see where +your misconceptions + +lie about this topic. + +So it can be very, very-- it +should be very, very focused. + +It's not just a +busywork question + +it's a focused question +with focus distractors. + +The distractors are +the incorrect answers. + +AUDIENCE: Can we do this? + +I want to see what the +spread of answers is. + +JANET RANKIN: Sure. + +Let's do it. + +AUDIENCE: They asked +this question-- + +I laughed, because they +asked a very similar question + +at Harvard graduation. + +JANET RANKIN: Exactly. + +What was it called, +a world of their own? + +AUDIENCE: Yeah one of those. + +JANET RANKIN: Two times, check. + +I've got to clear my responses. + +Let's go. + +So I'm getting you folks in +the back without a problem. + +I got one. + +I'm missing one of you. + +Wow. + +So there's any number +of things I could ask. + +We're going to do +another pair, share + +around this kind of thing. + +But maybe not for this one. + +But this is amazing. + +Basically it's A +got three votes. + +B got three votes. + +C got four votes. + +And D got three votes. + +So it's pretty amazing. + +AUDIENCE: What is +the right answer? + +JANET RANKIN: Biologists? + +AUDIENCE: B. + +JANET RANKIN: The answer +is B. And it's the most-- + +maybe not surprising-- +but the idea + +that it's taking in +things from the air. + +They're taking in gases. + +But there's chemical reactions +which manifest themselves + +in a weight gain. + +[INTERPOSING VOICES] + +It's not a biology +class, which is why-- + +so that's just super telling. + +That would be incredible. + +If this were a biology class +and that was the spread, + +that would just be +really, really informative + +for the instructor. + +AUDIENCE: Really worrying. + +JANET RANKIN: Well +yeah, that too. + +But it's biology class. + +So don't worry. + +But you do want to think +very, very carefully + +about the wrong +answers, because you + +want the wrong +answers to tell you + +something about what students +understand or don't understand. + +Generally speaking in +the adoption of clickers, + +plickers, whatever, takes +a three step process. + +One is that people +generally start + +with these simple +fact questions, + +and then more challenging +conceptual questions, which + +I would put the +one we just did at. + +That students, they might-- + +arguing with each +other could be useful. + +And then the third +is you've just + +totally revamped the lecture. + +And it's all centered +around these questions. + +And depending on +how students answer, + +that's how you navigate +through the lecture + +or through the +course, class period. + +I would never recommend that +anybody start with this one. + +I think that we're all capable +of starting with two actually. + +And I think starting with +three may be a waste of time, + +unless you really just want +to check and see if people + +did the reading or something. + +It's a big class. + +And you just want to see if +they've done the reading. + +But in general, I would +say put your energy + +into coming up with some +really good questions. + +And maybe don't ask as many. + +And then as I keep +saying, I hope + +you can start to see how +that's really, really linked. + +It's a measure of +whether they get it. + +But it's also an activity +to help them get it. + +So I've been minoring +the Back Channel. + +Nobody's saying anything +except for Dave. + +And I answered him. + +And because I gave +you a break before, + +I may scoot on, continue on. + +So if you want take a second +and login, that's fine. + +But I may not-- + +AUDIENCE: That's the +link for last year's. + +AUDIENCE: I entered it, and I +put entered into last year's. + +And I got really confused. + +JANET RANKIN: Uh oh. + +So the one for this +year is back here. + +Hold on. + +AUDIENCE: It's like +four something, + +4125 instead of 3969. + +JANET RANKIN: Oh OK, thank you. + +So while you're +doing that, I'm going + +to set up something which +is called lightning round. + +And we're doing these two. + +So I'm going to just, +sitting in your seat, + +if you can think about this +question, just the question + +on the left. + +Based on research +at NASA, what was + +the approximate net global +change in temperature + +between 1880 and 1975? + +It's not a plicker question. + +It's just a question. + +Try to think about what +you think the answer is. + +AUDIENCE: What is +Celsius to Fahrenheit? + +JANET RANKIN: To get from +Celsius to Fahrenheit? + +So you have to-- + +well I always just +double it and add 30. + +So it's 8/5 plus 32. + +[INTERPOSING VOICES] + +8/56 plus 32 is +the real equation. + +Is it 8/5 or 9/5? + +AUDIENCE: 9. + +JANET RANKIN: 9/5 That's +why I just double it. + +Close enough. + +So what I'm going to ask +is that-- let's see-- + +David, Gordon, and Julie. + +And if you can move down, +down, just to the end. + +And then if Adam, [INAUDIBLE], +Dave can come around? + +Just keep going. + +Keep going. + +That's fine. + +One, two, three, four-- no, no. + +You have to stand up, guys. + +No relaxing. + +Yes, but that's not-- + +I can tell a story. + +Please stand up and move over. + +Move over. + +And just keep coming around. + +Everybody's up. + +Everybody's doing this. + +Michelle, so I +need six, Michelle + +come on over here +next to [INAUDIBLE]. + +That's fine. + +Now [INAUDIBLE], +you come around here + +please, and go +opposite David, please. + +And everybody else just file +in and go opposite someone. + +Sarah, do you want +to participate? + +So here's what happens. + +I'm going to tell you to go. + +And you have two minutes. + +The person in this line +takes some amount of time + +and says what their answer +is and why they chose it. + +And the person in that line +can ask questions or whatever, + +and then say what they thought +and say why they thought that. + +So you're going to have a +really quick conversation + +about your choices. + +And after two minutes, I'm going +to tell you to please stop. + +And then you have +to get a new person. + +And I'll show you +how to do that. + +Everybody understand +what we're doing? + +You're having a two +minute exchange of ideas. + +And it's going to be loud. + +Believe me. + +And it's the person +opposite you. + +Are you ready? + +Everyone ready? + +On your mark, get set, go. + +[INTERPOSING VOICES] + +Let me ask a question. + +Did you encounter people that +had different choices than you? + +AUDIENCE: Yes. + +JANET RANKIN: Yes. + +So that generally means +it's a pretty good question, + +because you get to hear lots +of different perspectives. + +Now if this were the central +part of the class, this topic, + +you might let the pairings +go even longer, even more + +pairings. + +So did anybody change +their mind based on what + +they heard a partner say? + +OK, a couple of you. + +Generally, what +happens then is you + +would want to have +a de-brief, where + +we talk about why you +picked the answer you picked + +and what you picked. + +And most of the +time, the choices + +are a little been informative. + +If you found, as the instructor, +that everybody picked + +a negative number, well you're +in a very different place + +than if people are arguing +over how much positive it is. + +So you're going to +use that information + +to find out about where +the misconceptions are. + +What's the advantage +of this method? + +Gordon. + +AUDIENCE: It's very +interesting, I thought. + +One I found out is that the +students talk to each other. + +We never talk to each other. + +And it's easier for +them as to [INAUDIBLE]. + +So at the beginning, they +are aware of conflicts. + +But as we rotated, +there was a convergence. + +It was very interesting. + +JANET RANKIN: [INAUDIBLE] +have your hand up. + +AUDIENCE: Yes, one time +I was laughing just + +because it was very effective. + +There was so much [INAUDIBLE]. + +And when we started, +one resisted + +some passionated idea about +this is how it should be. + +And by the time it +went to all the people, + +people can get all the idea. + +You try to look for +the superior idea. + +Then you decide, +oh, this is better. + +When we try to switch again, +you listen to a better argument. + +So from which one decides +without [INAUDIBLE] + +the first one? + +JANET RANKIN: A +couple of points. + +One is that it's impossible not +to-- when you pair people up, + +it's pretty hard for +somebody not to participate. + +So if you have somebody +that's resistant, + +they might still be resistant. + +But it's virtually impossible +for them not to participate. + +And also it's a +little less scary. + +One person, it's really noisy. + +You know you only have to talk +to them for a minute or two. + +So it's a little less scary. + +Everybody's doing it. + +The other thing is that +you definitely want + +to have some sort of de-brief. + +You can't just stop and +go, OK, let's go on. + +You're going to have to find +out what people's answers are. + +And you're going to have to +address it or at least reveal + +the right answer, because +there's many places + +many, many places +for misconception. + +And also, then, if +you do it enough, + +you can maybe-- +students can find + +arguments or people's +explanations that + +resonate with them. + +And then you get exposed to +different kinds of arguments + +or different kinds of ways +of explaining the problem. + +So in this case, the answer is +actually positive 0.4 degrees. + +So B is the correct +answer, just so you know. + +AUDIENCE: Yes, I +just want to make + +a comment that sometimes this +method could be confusing + +as well. + +For instance, if you listen +to two superior arguments, + +one against. + +For instance, I talked to +someone who was actually + +in support of negative. + +And she brought an argument +and so forth like that. + +And somebody +thought of positive. + +And there was a strong +argument also for that. + +Sometimes if you just +be sitting on the fence, + +I don't know where to get off. + +JANET RANKIN: Well I think it's +OK to be confused for a while. + +That's fine. + +As I said, if this were a +course on global warming, + +climate change, whatever it +is, we would have to make sure + +that we heard all of +those explanations + +or a sampling of those +explanations and said, + +oh, well that's a good. + +I can see why you think that. + +But you've forgotten about this. + +Or I can see why, so +that you can process it + +all so that people +don't leave confused. + +But it's good to hear +the wrong answer, + +to be convinced of the +wrong answer, maybe, + +but then to see why it's wrong. + +That's an important +learning activity. + +AUDIENCE: But this +method is only + +applicable for where you have +cases where you can debate. + +Because if you have very clear +cases, for example, if I ask, + +what is the color of the sky? + +It's a definite. + +But when it's fuzzy, +then this can be-- + +JANET RANKIN: Yes, or +when it's a concept + +you think people might +have difficulty with. + +Yeah, it's not going to work +if it's a real clear cut. + +I want to demo one more method. + +This is think, pair, share. + +And I know we've been +doing those forever. + +But I'm going to couple it +with a clicker question. + +And I think we can do +it in seven minutes. + +So + +I have two blocks here, because +this is just too fun, really. + +I have two blocks. + +They're the same +width and the same. + +Length but they are +different thickness. + +And I have this thing. + +And I'm going to tap +on the thin block. + +Makes more or less-- + +it's not really a note. + +But it's some sound. + +And I'm going to +ask you, when I do + +the same thing, the same +force, the same place + +on the thick block, will +the note be higher, lower, + +or the same as the thin block? + +And this should be A, B, and +C, not one two and three. + +So but if it's A, +B, and C go ahead + +and vote with your plickers. + +Do you know that's what +they auto correct to? + +That's what it, if you're +typing and you write plickers, + +it autocorrects +to pluckers, which + +can be pretty embarrassing. + +AUDIENCE: So high +is for A. You've not + +clicked on the thicker one. + +JANET RANKIN: I know. + +That's why you have to tell +me what you think it is. + +AUDIENCE: Is this a A, B, and C? + +JANET RANKIN: A B +and C. So there's + +no D. There's a reason for this. + +If I told you the +answer, then there + +wouldn't be much fun in voting. + +And I have everybody. + +So I have a distribution. + +I'm not going to tell +you the distribution. + +I'm not going to share that +with you I'd like you to take-- + +just cluster. + +It could be groups of three or +four, whenever you have nearby, + +and talk about why you +picked the answer you picked. + +And then I'm going to give you +the opportunity to vote again. + +So in the interest of time, +two minutes to discuss this. + +[SIDE CONVERSATIONS] + +I wanted to just call attention +to a couple things I did. + +I walked around and tried to +eavesdrop on your conversations + +so that I could tell what +you were thinking about, + +but without putting +you on the spot, + +without asking you to say, +in front of everybody, + +what you thought. + +So that's one thing to do. + +Now I have a sense for +your mental models, + +how you're thinking +about the problem. + +So I have some really +good information + +about why you think +the answers you think. + +What I'm going to do is I'm +going to give you the chance + +to re-vote. + +If you want to change +your vote, you may. + +Or you don't have to. + +Some of the clicker +software actually + +lets you save +consecutive histograms, + +which can be useful. + +You can compare +if there's change. + +This doesn't let you do it. + +So I just have to-- + +AUDIENCE: Voting twice there? + +AUDIENCE: I'm voting +for [INAUDIBLE]. + +He's not present, so-- + +JANET RANKIN: Voting in +Chicago, early and often. + +We have exactly the +same distribution, + +which flies in the face +of some other data I + +was going to show you. + +But that's OK. + +I'll just in the interest of-- + +so one thing I could do +is I could call on you. + +And I could say, OK, if you +said it was lower, tell me + +why you thought it was lower. + +And I could get some +arguments for why you thought + +it was lower on the board. + +So some people think of cellos +make lower sounds than violins. + +And some people think that doors +on mansions have a low sound. + +And other people talked about +xylophones and the length + +and the wavelength +of the xylophone, + +and the longer wavelengths +for the longer pieces. + +So I know a lot about how you're +thinking about this problem. + +The other thing I +know is that I am not + +telling you the answer yet. + +So there's a little bit +of suspense in here. + +There's a little bit to +try to keep you interested + +and wanting to know, wanting +to understand the answer. + +AUDIENCE: Janet? + +JANET RANKIN: Yes? + +AUDIENCE: So you said we +had the same distribution. + +But can we have a show of +hands for how many people + +changed their answer? + +JANET RANKIN: That's +a great question. + +Yes. + +Raise your hand if you +changed your answer. + +It could've been amazing. + +AUDIENCE: So sometimes we've +done that in my physics class. + +When they ask, who +changed their answer? + +And everyone raises their hand. + +It's the same +exact distribution. + +Or everyone goes from +A and B to C and D. + +And even C and D originally +only had three people, + +you'll see the entire shift. + +And it turns out +A and B was right. + +When we vote the second time, +we all picked another answer. + +JANET RANKIN: That's very funny. + +That could have happened. + +Sometimes a nice +follow up question + +is how confident are +you in your answer. + +So then that's a really +good-- because you + +may have 80% of the +people h the right answer + +but if you say how confident +and hardly anybody is + +very confident then, you do +need to talk about it some more. + +So it gives you some really, +really good information. + +So here we go. + +Here's this one. + +It's higher. + +Exact same material. + +AUDIENCE: So when you play +the marimba and the xylophone, + +you have bigger bars. + +That they get really thin +when they're on the bass. + +The bass notes are really thin. + +And the really small high notes, +they're really, really thick. + +JANET RANKIN: So +that's one thing. + +The other thing is +that on a xylophone, + +it's a standing wave, because +you fixed the endpoints. + +And the wave just vibrates +based on the length + +of the pins, the separation +of the pins or the mounts. + +So in this case, it's +a free vibration. + +So that's another +different misconception. + +And then if you think-- so the +easiest way to think about it + +is a diving board. + +If you had a thin diving board, +and you went and jumped on it, + +it would go way down +and come back up again. + +That's a long wavelength. + +And that's a low note. + +And then if you think about +a stiffer diving board + +that you'd be kind of like, mmm. + +That's a shorter wavelength. + +So it's different. + +You have different-- and +then any kind of a cavity, + +like a cello or a door of a +house, if it's a big cavity, + +it's a bigger standing wave. + +It's still a standing wave. + +So those are very different. + +They are different models. + +So this technique +is really great, + +because it really gives you +incredible insight into what + +students' misconceptions are. + +And then you can really +make sure to address + +those misconceptions to deal +with their faulty models. + +So for the post-class +assignment, + +I've asked you to +think about what active + +learning techniques you might +adopt in your own teaching, + +in your own classes. + +And then think about how +you would adapt them, + +anticipate any +issues or whatever. + +So hopefully you've +gotten a good smattering. + +And I'll post the +slides, which have + +some links and things in there +if you want to look at videos. + +And also check out that +list from University + +of South Florida. + +That has some amazing techniques +that you might find useful. + +I'm going to send everybody off. + +But if you'd like to +comment on the mud cards-- + +I know we're over time-- + +I have them here, if you +want to make a comment. + +But otherwise, I will +see you next time. + +And I'd like the plickers back. \ No newline at end of file diff --git a/hJfqUAKMEdw.txt b/hJfqUAKMEdw.txt new file mode 100644 index 0000000000000000000000000000000000000000..10d3f97450191ba00831fa42acba45a3400032b1 --- /dev/null +++ b/hJfqUAKMEdw.txt @@ -0,0 +1,1301 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +view additional materials from hundreds + + align:start position:0% +view additional materials from hundreds + + + align:start position:0% +view additional materials from hundreds +of MIT courses visit MIT opencourseware + + align:start position:0% +of MIT courses visit MIT opencourseware + + + align:start position:0% +of MIT courses visit MIT opencourseware +at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu in this demonstration we're + + align:start position:0% +ocw.mit.edu in this demonstration we're + + + align:start position:0% +ocw.mit.edu in this demonstration we're +going to study the reflectivity of light + + align:start position:0% +going to study the reflectivity of light + + + align:start position:0% +going to study the reflectivity of light +at a dialectric interface or a piece of + + align:start position:0% +at a dialectric interface or a piece of + + + align:start position:0% +at a dialectric interface or a piece of +glass + + align:start position:0% +glass + + + align:start position:0% +glass +the setup is here we have a laser helium + + align:start position:0% +the setup is here we have a laser helium + + + align:start position:0% +the setup is here we have a laser helium +neon laser here's the beam from the + + align:start position:0% +neon laser here's the beam from the + + + align:start position:0% +neon laser here's the beam from the +laser be reflected by a + + align:start position:0% +laser be reflected by a + + + align:start position:0% +laser be reflected by a +mirror and then we pass it through a + + align:start position:0% +mirror and then we pass it through a + + + align:start position:0% +mirror and then we pass it through a +quarter wave plate so the light here is + + align:start position:0% +quarter wave plate so the light here is + + + align:start position:0% +quarter wave plate so the light here is +circularly + + align:start position:0% +circularly + + + align:start position:0% +circularly +polarized and then we passed the + + align:start position:0% +polarized and then we passed the + + + align:start position:0% +polarized and then we passed the +circular polarized light through this + + align:start position:0% +circular polarized light through this + + + align:start position:0% +circular polarized light through this +polarizer so that by varying the + + align:start position:0% +polarizer so that by varying the + + + align:start position:0% +polarizer so that by varying the +transmission AIS of the polarizer we can + + align:start position:0% +transmission AIS of the polarizer we can + + + align:start position:0% +transmission AIS of the polarizer we can +vary the state of polarization of the + + align:start position:0% +vary the state of polarization of the + + + align:start position:0% +vary the state of polarization of the +light coming through the polarizer and + + align:start position:0% +light coming through the polarizer and + + + align:start position:0% +light coming through the polarizer and +light goes onto a piece of glass here + + align:start position:0% +light goes onto a piece of glass here + + + align:start position:0% +light goes onto a piece of glass here +then we have the transmitted light which + + align:start position:0% +then we have the transmitted light which + + + align:start position:0% +then we have the transmitted light which +is here falling on this circular screen + + align:start position:0% +is here falling on this circular screen + + + align:start position:0% +is here falling on this circular screen +and the reflected light falls on the + + align:start position:0% +and the reflected light falls on the + + + align:start position:0% +and the reflected light falls on the +screen also so we can by varying the the + + align:start position:0% +screen also so we can by varying the the + + + align:start position:0% +screen also so we can by varying the the +angle of incidence here we can vary the + + align:start position:0% +angle of incidence here we can vary the + + + align:start position:0% +angle of incidence here we can vary the +spot on the + + align:start position:0% +spot on the + + + align:start position:0% +spot on the +on the screen + + align:start position:0% +on the screen + + + align:start position:0% +on the screen +so first we'll start with vertically + + align:start position:0% +so first we'll start with vertically + + + align:start position:0% +so first we'll start with vertically +polarized light or transverse + + align:start position:0% +polarized light or transverse + + + align:start position:0% +polarized light or transverse +electric by setting the polarizer + + align:start position:0% +electric by setting the polarizer + + + align:start position:0% +electric by setting the polarizer +here along the vertical axis and the + + align:start position:0% +here along the vertical axis and the + + + align:start position:0% +here along the vertical axis and the +arrow the white Arrow indicates uh + + align:start position:0% +arrow the white Arrow indicates uh + + + align:start position:0% +arrow the white Arrow indicates uh +vertical polarization so we'll start + + align:start position:0% +vertical polarization so we'll start + + + align:start position:0% +vertical polarization so we'll start +with a small angle of + + align:start position:0% +with a small angle of + + + align:start position:0% +with a small angle of +incidence close to zero and then we + + align:start position:0% +incidence close to zero and then we + + + align:start position:0% +incidence close to zero and then we +slowly work up and what you want to + + align:start position:0% +slowly work up and what you want to + + + align:start position:0% +slowly work up and what you want to +watch is here we go through + + align:start position:0% +watch is here we go through + + + align:start position:0% +watch is here we go through +20° 30° or so and what you see is that + + align:start position:0% +20° 30° or so and what you see is that + + + align:start position:0% +20° 30° or so and what you see is that +the intensity of the light + + align:start position:0% +the intensity of the light + + + align:start position:0% +the intensity of the light +increases as we + + align:start position:0% +increases as we + + + align:start position:0% +increases as we +approach 90° we're here 80 and then 90 + + align:start position:0% +approach 90° we're here 80 and then 90 + + + align:start position:0% +approach 90° we're here 80 and then 90 +and you can see that the light gets + + align:start position:0% +and you can see that the light gets + + + align:start position:0% +and you can see that the light gets +pretty + + align:start position:0% +pretty + + + align:start position:0% +pretty +bright the uh now we go back again + + align:start position:0% + + + + align:start position:0% + +here's + + align:start position:0% + + + + align:start position:0% + +50° + + align:start position:0% + + + + align:start position:0% + +40° and so on all the way down to to + + align:start position:0% +40° and so on all the way down to to + + + align:start position:0% +40° and so on all the way down to to +zero angle of + + align:start position:0% +zero angle of + + + align:start position:0% +zero angle of +incidence now what I'm going to do is + + align:start position:0% +incidence now what I'm going to do is + + + align:start position:0% +incidence now what I'm going to do is +change the state of polarization to the + + align:start position:0% +change the state of polarization to the + + + align:start position:0% +change the state of polarization to the +horizontal + + align:start position:0% + + + + align:start position:0% + +one by + + align:start position:0% +one by + + + align:start position:0% +one by +changing the transmission axis of the of + + align:start position:0% +changing the transmission axis of the of + + + align:start position:0% +changing the transmission axis of the of +the polarizer + + align:start position:0% + + + + align:start position:0% + +and then now let's look at the + + align:start position:0% +and then now let's look at the + + + align:start position:0% +and then now let's look at the +reflectivity as a function of angle of + + align:start position:0% +reflectivity as a function of angle of + + + align:start position:0% +reflectivity as a function of angle of +incidence here again with polarization + + align:start position:0% +incidence here again with polarization + + + align:start position:0% +incidence here again with polarization +along the horizontal plane or P + + align:start position:0% +along the horizontal plane or P + + + align:start position:0% +along the horizontal plane or P +polarization let's see now what happens + + align:start position:0% +polarization let's see now what happens + + + align:start position:0% +polarization let's see now what happens +so we start again about 4% here's 10° + + align:start position:0% +so we start again about 4% here's 10° + + + align:start position:0% +so we start again about 4% here's 10° +marker + + align:start position:0% +marker + + + align:start position:0% +marker +20° + + align:start position:0% +20° + + + align:start position:0% +20° + + align:start position:0% + + + align:start position:0% +40 and now you you can see that the + + align:start position:0% +40 and now you you can see that the + + + align:start position:0% +40 and now you you can see that the +light is getting dimmer and dimmer here + + align:start position:0% +light is getting dimmer and dimmer here + + + align:start position:0% +light is getting dimmer and dimmer here +is 50 and here we reach the Brewster + + align:start position:0% +is 50 and here we reach the Brewster + + + align:start position:0% +is 50 and here we reach the Brewster +angle where the intensity is zero and + + align:start position:0% +angle where the intensity is zero and + + + align:start position:0% +angle where the intensity is zero and +then here is + + align:start position:0% +then here is + + + align:start position:0% +then here is +60° + + align:start position:0% +60° + + + align:start position:0% +60° +70 80 and you can see the light + + align:start position:0% +70 80 and you can see the light + + + align:start position:0% +70 80 and you can see the light +intensity is getting bigger and bigger + + align:start position:0% +intensity is getting bigger and bigger + + + align:start position:0% +intensity is getting bigger and bigger +and + + align:start position:0% +and + + + align:start position:0% +and +bigger in order to look at it a little + + align:start position:0% +bigger in order to look at it a little + + + align:start position:0% +bigger in order to look at it a little +bit better let's dim the room lights and + + align:start position:0% +bit better let's dim the room lights and + + + align:start position:0% +bit better let's dim the room lights and +do the experiments again + + align:start position:0% + + + + align:start position:0% + +we're going to start with vertical + + align:start position:0% +we're going to start with vertical + + + align:start position:0% +we're going to start with vertical +polarization + + align:start position:0% +polarization + + + align:start position:0% +polarization +or S polarization or if you wish + + align:start position:0% +or S polarization or if you wish + + + align:start position:0% +or S polarization or if you wish +transverse electric and then we'll start + + align:start position:0% +transverse electric and then we'll start + + + align:start position:0% +transverse electric and then we'll start +varying the angle of incidence from zero + + align:start position:0% +varying the angle of incidence from zero + + + align:start position:0% +varying the angle of incidence from zero +here is 10 + + align:start position:0% +here is 10 + + + align:start position:0% +here is 10 +de 20 and you can see that the light + + align:start position:0% +de 20 and you can see that the light + + + align:start position:0% +de 20 and you can see that the light +intensity is increasing here's + + align:start position:0% +intensity is increasing here's + + + align:start position:0% +intensity is increasing here's +30 40 and you can see it's increasing + + align:start position:0% +30 40 and you can see it's increasing + + + align:start position:0% +30 40 and you can see it's increasing +nicely + + align:start position:0% +nicely + + + align:start position:0% +nicely +50° here is + + align:start position:0% +50° here is + + + align:start position:0% +50° here is +60 70 now it's really getting + + align:start position:0% +60 70 now it's really getting + + + align:start position:0% +60 70 now it's really getting +bright + + align:start position:0% +bright + + + align:start position:0% +bright +80 and then as we approach 90 you can + + align:start position:0% +80 and then as we approach 90 you can + + + align:start position:0% +80 and then as we approach 90 you can +see that the angle the reflected beam is + + align:start position:0% +see that the angle the reflected beam is + + + align:start position:0% +see that the angle the reflected beam is +more intense than the transmitted beam + + align:start position:0% +more intense than the transmitted beam + + + align:start position:0% +more intense than the transmitted beam +and here we are very close to 90 and + + align:start position:0% +and here we are very close to 90 and + + + align:start position:0% +and here we are very close to 90 and +then again you see the other spots due + + align:start position:0% +then again you see the other spots due + + + align:start position:0% +then again you see the other spots due +to multiple + + align:start position:0% +to multiple + + + align:start position:0% +to multiple +Reflections and let's go back + + align:start position:0% + + + + align:start position:0% + +now here we are the Den is going + + align:start position:0% +now here we are the Den is going + + + align:start position:0% +now here we are the Den is going +down here's the 60° + + align:start position:0% +down here's the 60° + + + align:start position:0% +down here's the 60° +marker + + align:start position:0% +marker + + + align:start position:0% +marker +50° + + align:start position:0% +50° + + + align:start position:0% +50° +40 30 and so on all the way to to + + align:start position:0% +40 30 and so on all the way to to + + + align:start position:0% +40 30 and so on all the way to to +zero now what I'll do I'm going to + + align:start position:0% +zero now what I'll do I'm going to + + + align:start position:0% +zero now what I'll do I'm going to +change the + + align:start position:0% +change the + + + align:start position:0% +change the +polarization to horizontal + + align:start position:0% +polarization to horizontal + + + align:start position:0% +polarization to horizontal +polarization or p polariz + + align:start position:0% +polarization or p polariz + + + align:start position:0% +polarization or p polariz +ation but just to make sure I have it + + align:start position:0% +ation but just to make sure I have it + + + align:start position:0% +ation but just to make sure I have it +right I'm going to do a little + + align:start position:0% + + + + align:start position:0% + +check on + + align:start position:0% +check on + + + align:start position:0% +check on +the on the Brewster angle and then and + + align:start position:0% +the on the Brewster angle and then and + + + align:start position:0% +the on the Brewster angle and then and +then we'll start again so here now + + align:start position:0% +then we'll start again so here now + + + align:start position:0% +then we'll start again so here now +with with this horizontal + + align:start position:0% +with with this horizontal + + + align:start position:0% +with with this horizontal +polarization I'm going to now vary the + + align:start position:0% +polarization I'm going to now vary the + + + align:start position:0% +polarization I'm going to now vary the +angle of incidence as we watch the spot + + align:start position:0% +angle of incidence as we watch the spot + + + align:start position:0% +angle of incidence as we watch the spot +on the screen + + align:start position:0% + + + + align:start position:0% + +you can see the spots the intensity is + + align:start position:0% +you can see the spots the intensity is + + + align:start position:0% +you can see the spots the intensity is +going down here's a 20° + + align:start position:0% +going down here's a 20° + + + align:start position:0% +going down here's a 20° +marker + + align:start position:0% +marker + + + align:start position:0% +marker +30 40 and now the spot's getting + + align:start position:0% +30 40 and now the spot's getting + + + align:start position:0% +30 40 and now the spot's getting +dimmer even more + + align:start position:0% +dimmer even more + + + align:start position:0% +dimmer even more +50 and as we get close to the Brewster + + align:start position:0% +50 and as we get close to the Brewster + + + align:start position:0% +50 and as we get close to the Brewster +angle goes to zero + + align:start position:0% +angle goes to zero + + + align:start position:0% +angle goes to zero +56.5 then here at + + align:start position:0% +56.5 then here at + + + align:start position:0% +56.5 then here at +60° + + align:start position:0% +60° + + + align:start position:0% +60° +70° it's picking up intensity fast 80 + + align:start position:0% +70° it's picking up intensity fast 80 + + + align:start position:0% +70° it's picking up intensity fast 80 +and as it gets close + + align:start position:0% +and as it gets close + + + align:start position:0% +and as it gets close +to 90° intensity heads towards 100% And + + align:start position:0% +to 90° intensity heads towards 100% And + + + align:start position:0% +to 90° intensity heads towards 100% And +certainly looks brighter than the + + align:start position:0% +certainly looks brighter than the + + + align:start position:0% +certainly looks brighter than the +transmitted intensity also of course you + + align:start position:0% +transmitted intensity also of course you + + + align:start position:0% +transmitted intensity also of course you +see the effective multiple Reflections + + align:start position:0% +see the effective multiple Reflections + + + align:start position:0% +see the effective multiple Reflections +so let's go + + align:start position:0% +so let's go + + + align:start position:0% +so let's go +back is + + align:start position:0% +back is + + + align:start position:0% +back is + + align:start position:0% + + + align:start position:0% +70 60 getting nice and dim and at + + align:start position:0% +70 60 getting nice and dim and at + + + align:start position:0% +70 60 getting nice and dim and at +56.5 goes to zero and then picks up + + align:start position:0% +56.5 goes to zero and then picks up + + + align:start position:0% +56.5 goes to zero and then picks up +again at 50 so now let's go back to to + + align:start position:0% +again at 50 so now let's go back to to + + + align:start position:0% +again at 50 so now let's go back to to +the rooster angle where it's + + align:start position:0% +the rooster angle where it's + + + align:start position:0% +the rooster angle where it's +extinguished where the light is pretty + + align:start position:0% +extinguished where the light is pretty + + + align:start position:0% +extinguished where the light is pretty +close to zero and let me then change the + + align:start position:0% +close to zero and let me then change the + + + align:start position:0% +close to zero and let me then change the +polarization back to to ver to + + align:start position:0% +polarization back to to ver to + + + align:start position:0% +polarization back to to ver to +Vertical here we are go back to the + + align:start position:0% +Vertical here we are go back to the + + + align:start position:0% +Vertical here we are go back to the +vertical and we see that the + + align:start position:0% +vertical and we see that the + + + align:start position:0% +vertical and we see that the +spot gets brighter and + + align:start position:0% +spot gets brighter and + + + align:start position:0% +spot gets brighter and +brighter so here it it is with vertical + + align:start position:0% +brighter so here it it is with vertical + + + align:start position:0% +brighter so here it it is with vertical +polarization and here is the + + align:start position:0% +polarization and here is the + + + align:start position:0% +polarization and here is the +intensity with horizontal + + align:start position:0% +intensity with horizontal + + + align:start position:0% +intensity with horizontal +polarization in summary we have shown + + align:start position:0% +polarization in summary we have shown + + + align:start position:0% +polarization in summary we have shown +how light is reflected at a dialectric + + align:start position:0% +how light is reflected at a dialectric + + + align:start position:0% +how light is reflected at a dialectric +interface or a piece of + + align:start position:0% +interface or a piece of + + + align:start position:0% +interface or a piece of +glass we've shown that for polarization + + align:start position:0% +glass we've shown that for polarization + + + align:start position:0% +glass we've shown that for polarization +in the vertical plane or S polarization + + align:start position:0% +in the vertical plane or S polarization + + + align:start position:0% +in the vertical plane or S polarization +the reflectivity goes from about 4% for + + align:start position:0% +the reflectivity goes from about 4% for + + + align:start position:0% +the reflectivity goes from about 4% for +zero angle of incidence to 100% for + + align:start position:0% +zero angle of incidence to 100% for + + + align:start position:0% +zero angle of incidence to 100% for +90° angle of incidence in contrast for + + align:start position:0% +90° angle of incidence in contrast for + + + align:start position:0% +90° angle of incidence in contrast for +horizontal polarization or P + + align:start position:0% +horizontal polarization or P + + + align:start position:0% +horizontal polarization or P +polarization the reflectivity again + + align:start position:0% +polarization the reflectivity again + + + align:start position:0% +polarization the reflectivity again +starts at 4% but goes down to zero at + + align:start position:0% +starts at 4% but goes down to zero at + + + align:start position:0% +starts at 4% but goes down to zero at +the Brewster angle and in this case for + + align:start position:0% +the Brewster angle and in this case for + + + align:start position:0% +the Brewster angle and in this case for +glass it's 56.5 de and then goes rapidly + + align:start position:0% +glass it's 56.5 de and then goes rapidly + + + align:start position:0% +glass it's 56.5 de and then goes rapidly +up to 100% + + align:start position:0% +up to 100% + + + align:start position:0% +up to 100% +for 90° angle of incidence \ No newline at end of file diff --git a/i59JDQ9hk10.txt b/i59JDQ9hk10.txt new file mode 100644 index 0000000000000000000000000000000000000000..129622cc547b038bd7a761c0c195cfef69e7bde8 --- /dev/null +++ b/i59JDQ9hk10.txt @@ -0,0 +1,4269 @@ +The following +content is provided + +under a Creative +Commons license. + +Your support will help MIT +OpenCourseWare continue + +to offer high quality +educational resources for free. + +To make a donation or +view additional materials + +from hundreds of MIT courses, +visit MIT OpenCourseWare + +at ocw.mit.edu. + +DOUG LAUFFENBURGER: +So we shall start. + +I haven't had the pleasure +of meeting most of you. + +I'm Doug Lauffenburger. + +I'm gratefully invited for +a guest presentation here. + +So I'll definitely enjoy it. + +There should be plenty of time. + +I'm not racing through +a lot of material, + +so feel free to interrupt +me with questions. + +And of course I'll try +to respond as best I can. + +OK. + +Who has looked at the +background materials that + +were posted on the web a +long time ago, last night? + +Who already will admit +to having looked at it? + +Good. + +All right. + +I guess that means +I should do this + +because otherwise if +you've read it already then + +there'd be no point, right? + +OK. + +OK. + +Well, where we are +in your semester-- + +you're learning a lot of things +across the whole spectrum + +of computational +systems biology. + +I hope I'll add +something in here. + +It's actually a +very specific topic. + +We talk about modeling of +cell signaling networks, + +and in particular, one approach +is worth going through today + +and that's the logic +modeling framework. + +So I'll give you a little bit +of a conceptual background + +for the first 10 or 15 minutes. + +Then we'll launch into +the particular example + +that was in the main paper. + +And a little side light +with an application of it + +to a particular cancer problem. + +And then that should take +us pretty much to the end. + +OK. + +OK. + +The biological topic here +is cell signaling, primarily + +mammalian cells. + +Certainly applicable +to microbial cells + +in a simpler sense. + +So just to place the context, +in mammalian cell biology, + +I'm a bio-engineer and a cell +biologist at the same time. + +We're very interested in what +controls the cell behavior, + +their phenotypic response. + +We know that it's +in fact controlled + +by what it sees in their +environment, growth + +factors, hormones, extracellular +matrix, mechanical forces, + +cell-cell contacts. + +A variety of queues +in the environment + +and the way these govern +phenotype or control phenotype + +is that they influence, +they regulate + +what I would call the +execution processes. + +The crucial execution processes +such as gene expression, + +transcription, and +translation are + +governed by +extracellular factors. + +Metabolism, synthesis +of new molecules, + +cytoskeleton, motors, +forced generation. + +These things all +carry out phenotype + +governed by the extracellular +stimuli or cues. + +And it happens via these +biochemical signaling + +pathways that are activated +primarily by cell surface + +receptors in the plasmid +membrane-- cascades + +of biochemical reactions, +mostly enzymatic. + +Some protein-protein +docking, mostly + +post-translational +modifications. + +Kinase phosphate reactions +adding and taking off + +phosphate groups that change +protein activities at locations + +and so forth. + +It could be other types of +post-translation modifications. + +It could be second messengers, +calcium, ATP aces and so forth. + +So, the extracellular-- +now my battery's dead. + +That's not good. + +Oh, there we go. + +Extracellular stimuli, +generate the signals. + +They regulate gene expression, +metabolism, cytoskeleton. + +They carry out phenotype. + +OK. + +So we want to learn about cell +signaling network operations. + +There's actually multiple +pathways involved. + +We really need to +study many of them + +in concert to understand +what the cells are doing. + +And a big question is, +what kind of information + +do we need to study this? + +And on the end, we'd +be interested in how + +phenotypic behavior does arise +from variations and mutations + +in the genomic content of cells. + +But that genomic content, +of course, is not modified, + +but its effects are +influenced by what's + +the environment to these +extracellular cues, + +log ins and so forth. + +So they influence what +message is expressed. + +From that message +they influence what's + +actually translated +into protein. + +From those proteins +they influence + +the post-translational +modifications + +and what the proteins +are actually doing. + +And so, in the +end, the phenotype + +is carried out by these +protein operations. + +And the question +is, what information + +level that we might +want to study. + +And of course you would +love to have the information + +content at all levels-- +genomic information, + +transcriptional information, +translational information, + +post-translational information. + +So integrating all those +different data levels + +can be extremely valuable. + +In terms of the models I'm +going to talk about today, + +they've essentially +been living at the level + +of protein activities in +these signaling pathways. + +OK. + +That will be the +kind of data sets + +you'll see that will be analyzed +with respect to the models. + +Obviously, they arise from +these underlying mechanisms + +that, as influenced by +the environmental context, + +altering the signaling +protein activities. + +OK. + +And what's very +interesting and there's + +going to be more and more +progress in the coming years + +is relating what's in the +genomic information-- mutations + +and variations to what's +happening at the protein level. + +And some of the other +instructors in this class + +are really some of +the world's experts + +in figuring out how to do this. + +I'd like to just +show this example + +as a motivation for +this kind of approach. + +And that is if you do gene +sequencing of many patient + +tumors-- in this +case, I believe this + +was a paper on +pancreatic tumors. + +This has been shown for pretty +much every other type of tumor + +since then. + +In any given patient tumor, +each one of these bars, + +there's dozens of +mutations in each tumor. + +And a variety of +types-- deletions, + +amplifications mutations +and by and large, they're + +all different. + +There's very few +mutations themselves + +that really carry over to +a substantial proportion + +of one patient's +tumor to another. + +There's some special cases +that are fairly pervasive, + +but the predominant of these +dozens and dozens of mutations + +and variations are +different from one patient + +to another, and even +in the same patient. + +So what's emerging +as a productive way + +to think about this-- How +do all these different types + +of mutations and +specific mutations + +actually lead to classes +of similar pathologies? + +And that is they +tend to reside in + +what can be identified +as pathways-- circuits, + +machines, things that +are actually carrying out + +function at the protein level. + +So for instance-- I'm +losing this again. + +For these pancreatic +cancers on this wheel + +are about a dozen different +signaling pathways + +and self-cycle control +pathways and apoptosis + +controlled pathways. + +And if you look at any +individual patient tumors, + +like this green one or this red +one-- two different patients. + +If you actually look at the +mutations at the genomic level, + +they're entirely different +in the green patient + +tumor versus the +red patient tumor. + +So if you're just trying +to match gene mutation + +to pancreatic cancer, +these two patients + +would look entirely different. + +But, it turns out, that you +can line up their mutations + +into the same +pathways and say, OK, + +the red tumor and +the green tumor + +both have mutations that +affect the TGF beta pathway. + +They're different +mutations, but they've just + +regulated that pathway. + +And similarly, you can +do that with pretty much + +all of the other mutations. + +That these tumors +have been dysregulated + +in terms of particular pathways. + +But patient to +patient to patient, + +it's happened by different +genomic gene sequence + +mutations. + +So that the ability to +look at these protein + +level pathways is +a way of making + +really good productive sense +of the gene sequencing data. + +So there's lots of labs trying +to go from gene sequence + +up to pathway modulation. + +In our case, we're not +going to show you that here. + +We're going to say, +this is a motivation + +for starting at +the protein level. + +And I'd like to show +this picture too. + +Number one because it's +such an anachronism. + +This is a circuit board from +decades and decades and decades + +ago that none of +you would recognize. + +But, in the molecular biology +world, this kind of a picture, + +and in its modern form is viewed +as a very appealing metaphor + +for how to think +about these signaling + +pathways and signaling networks +that take the extracellular + +information and turn it into +governance of transcription, + +metabolism, cytoskeleton, +and phenotype. + +So, just this +metaphor of circuitry, + +where in white, the +extracellular ligands, + +growth factors are +somehow wired to the blue. + +The cell surface receptors, +or B for instance-- + +they're wired too. + +Kinases and other +signaling proteins-- + +they're wired to transcription +factors, self-cycle control + +regulators, +apoptosis regulators. + +So these very famous folks +in cancer biology say, + +what you've got to understand +is, these signalling networks + +as circuitry. + +And if the circuitry is +dysregulated somehow, + +the wiring is different, +then that's what's + +underlying malignant behavior. + +So, this is really +beautiful but it's + +pretty much useless, right. + +Because there's no prediction or +calculation or even hypothesis + +generation one can do +from a picture like this. + +Yes, it's circuitry, but +what do I do with it? + +So, what I want +to show you today + +are efforts to +turn them into what + +I would call an actionable +model, a computable model. + +Yes, it looks kind +of like circuitry, + +but in fact you would know +how to do a calculation that + +would fit it to data +and predict new data. + +And then you have, in fact, a +model rather than a metaphor. + +That's the idea. + +So, one question is, if +you want to turn that + +into a formal mathematical +framework for circuitry + +that you can calculate-- +what kind of mathematics + +might you use? + +And in this class +you're learning + +a whole spectrum of things. + +And one can think +about it on one hand, + +if we knew all of +those components + +and how they interacted, and +could estimate rate constance + +and so forth, we could +write differential equations + +for maybe the dozens and dozens +of components and interactions + +and predict how they would +play out dynamically with time. + +For most systems with +the complexity that's + +really controlling cell +biology, at this point in time, + +this is almost impossible. + +There's only rare +cases where enough + +is known about +signaling biochemistry + +to really write +down differential + +equations for what's going on. + +At the other extreme, +of course, is the type + +of mathematics one gets out +of very, very large data sets, + +sequencing data sets, +transcriptional, and so forth. + +More informatics +type of analysis, + +where it has to do +with multivariate + +regression and clustering, +mutual information. + +And what we've been working on +is someplace up in the middle + +where you don't have enough +mechanistic prior knowledge + +to write this formal +of physics, and yet + +takes you someplace beyond +statistical associations. + +And this is one +of the areas that + +might be worth your +learning in this class. + +OK, this is really the same +set of computational methods, + +just like it's cast in a +little bit different form that + +delineates competition +modeling, really + +into two kinds of classes. + +What's traditionally appreciated +in most fields of engineering + +and physics are +differential equations + +that are very theory driven. + +You have a theory. + +You have prior knowledge +for what's happening. + +You're writing down the +components involved, + +you're writing down +how they interact. + +And typically, +algebraic equations + +for those differential +equations describe your theory, + +describe your prior knowledge. + +And now it's formalized and +you estimate rate constants + +and so forth. + +Another whole class +of information + +is data driven, in +which, you really + +don't have a good theory +about what components matter + +and how they interact. + +And so you start with +data sets and from it + +you do classification or +typologies or associations + +with different types of +mathematics that at least try + +to make sense and get hypotheses +out of these large data + +sets, where you don't +have any theory. + +One reason that logic +modeling appeals to me, + +is that it actually +can be applied + +in either the theory driven +or the data driven mode. + +You can say, I know +nothing about my system. + +I just generate large data sets +of signaling network activities + +induced by different +stimuli, but I'm + +going to try to fit a +logic model to it that + +says how the different +components influencing + +each other in a logic way. + +Or, you could say, +well, I know something. + +I have some prior knowledge. + +I may have interact ohms the say +what molecular components are + +present in signaling networks. + +And so in principle, I +kind of know who's involved + +and who might be +influencing whom. + +And I could write a logic model +based on that prior knowledge. + +And then run calculations +and see if it actually + +makes predictions about +experimental data. + +So that's one nice thing. + +It's a mathematical +formalism that + +can either be run in data driven +mode or in theory driven mode + +and go back and forth. + +So that's one reason-- +given one lecture to offer, + +I've decided to offer +it on this topic. + +All right, with me so far? + +Any questions? + +Philosophy? + +OK. + +So, what we're +going to do today is + +almost take a +hybrid of these two. + +We're going to say, what +prior knowledge do we have, + +and then recognize that +it's really not enough. + +And so how do we now integrate +that with empirical data + +to now come up with +logic modeling that, + +in fact, is actionable +and computable? + +OK. + +So what kind of prior +knowledge do we have? + +Let's say we wanted to have +a logic model for what's + +in these signaling networks +down stream of growth factor + +receptors, or hormone receptors, +or things like that, that then + +govern gene expression, +metabolism and so forth. + +What prior knowledge do we have? + +And you folks +probably have already + +seen some of this in the class. + +There's all kinds of +databases of stuff. + +What's in those databases +that might be relevant here? + +AUDIENCE: [INAUDIBLE] that the +protein-protein interactions-- + +if you switch proteins, they +interact with each other, + +but maybe not necessarily +what pathways they're in. + +DOUG LAUFFENBURGER: OK, good. + +And have you seen +databases like that? + +AUDIENCE: Several of +them have come up. + +DOUG LAUFFENBURGER: OK. + +Are you the only +one who's seen them? + +Or is there anybody +else that kind + +of noticed them in passing too? + +OK, good. + +Second, third, +fourth, all right. + +That's a critical mass +if I ever saw one. + +OK. + +So, I'm just going +to allude to those. + +So there are pathway databases. + +And this is actually an +old slide of a few years + +ago, so I'm sure the +numbers are all different. + +And, in fact, there's new ones. + +I just haven't taken +to updating the slide. + +But we'll, based on literature, +take certain numbers + +of gene products, a +few hundred of them, + +and organize them into pathways +based on biological knowledge. + +There's other databases that +are more interactomes, usually + +based on other kinds of +experimental data-- yeast II + +hybrid, mass spectrometry, +literature curation, + +that also tries to say who's +physically interacting. + +So these node-- these pathway +databases don't necessarily + +say, somebody's +physically interacting, + +they say somebody might +be upstream and downstream + +and so forth. + +And then they +interactome databases + +say, component a +and component b, + +there's some evidence that they +have a physical association + +someplace along the way. + +So these are two +complementary types + +of databases that, in +fact, can be put together. + +OK. + +So an interesting +thing about these-- + +there's a number +of these databases. + +And so in principle +you could say, well + +if I want then to start-- if +I want to generate a logic + +model for signaling +networks, all + +I have to do is take +what's in the database + +and say what pathways +are there and what's + +known with their +interactions, and now I've + +got a starting point. + +You know, I can +actually draw a graph + +with lots of molecular nodes and +lots of molecular interactions. + +So, you can do that. + +And so you can choose +one of these databases + +and say I'm going +to draw a graph that + +has what's believed to be +true about nodes and pathways + +and interactions and +signaling networks. + +But then you choose a different +database and another database. + +And you'll actually get +different information. + +OK. + +We actually did a study +on this-- I probably + +should have given you the +citation of that-- that + +said if you look at six or +seven of these databases, + +they are not coincident. + +They have a very +small intersections. + +Most of their information +is non-redundant. + +And so you could try +to put it all together. + +And we did this, +again, in this paper + +that I'm not giving +you a citation for. + +And so here's a number of +nodes and signaling pathways + +downstream of receptors. + +And all the colored +nodes are those + +in which they appear in +only one of these-- one, two + +three, four, five, +six databases. + +So if something's colored +green, it's only in GeneGo + +and it's not in +any of the others. + +If something's +colored purple, it's + +in PANTHER and +none of the others. + +OK. + +If they're gray-- some +of these gray ones, + +they're in at least two. + +But out of these six, there's +an exceedingly small number + +of nodes interactions that +are in all six databases. + +Which was a real surprise +to us when we did this. + +So what this means +is, if you want + +to start with some +prior knowledge graph + +that you're now going to fit +a logic model to by mapping it + +against data, you first +even have the choice, well, + +what am I going to start with? + +What is my prior knowledge? + +There;s not really +consensus prior knowledge. + +So you can start with six +different interaction graphs. + +Or you could try to +put them all together + +and get a consensus graph. + +So you have all these choices. + +And right now, it's +not as if is there's + +detailed analysis of what +the best choice would + +be for your starting point. + +But I want to stress that, +with respect to our approach, + +this is a starting +point because one + +of the issues with the +database information + +is that it's typically +very diverse with respect + +to contact. + +What cell type did this +information come from? + +What treatment conditions +did it come from? + +If there's different cell +types, different species, + +different mutations. + +So if I see interactions or +if I don't see interactions, + +are they in conflict? + +Or they're just-- this +one was in a lymphocyte, + +this one was in a +hypatocye, this one + +was in a cardiac myocyte, and +they're actually different. + +OK, so if I had a cell +type specific database, + +or pulled that information +out, that would be good. + +It would be a smaller +number of things. + +But then under what +treatment conditions? + +Because remember I said starting +with the genomic content, what + +you actually see in terms +of molecular interactions + +will be very strongly +affected by what + +matrix were the +cells growing on? + +Or was this in vivo? + +Was this in a multicellular +culture situation? + +So, that's why this +is a starting point + +and can't really +be used to describe + +any particular experimental +situation with much confidence. + +The other thing-- +and this is what + +I've been trying to +emphasize from the start-- is + +that there's no calculation +you can do on this. + +There's a group of +folks in this field who + +propose some ideas that I +think are very intriguing, + +but which, at least +to me personally, + +there's not that +much evidence for. + +And that is, that there's +topological characteristics + +of these graphs, that then +tell you what's important. + +So if I have a +node that's somehow + +connected to more +other nodes, that + +is going to be a +more important node, + +and might be associated with the +disease, versus a node that's + +connected to fewer. + +OK. + +Some of these are very, very +appealing ideas conceptually. + +If you actually look for +the experimental evidence + +that they're valid +notions, it's very thin. + +But, that's where some +folks would claim, + +oh, you can do predictions +on the hypotheses based + +on these graphs because +there are these graph theory + +characteristics +that somehow might + +be biologically meaningful. + +OK. + +But I'd say, jury's out on +whether, in fact, any of that + +is true. + +So, our view is-- OK, this +is a good starting point, + +but in fact, needs to be +mapped to empirical data + +in order to gain confidence +about calculations you can do. + +So that's the goal of +this kind of approach, + +is to say, let's +stipulate that we start + +with some prior +knowledge scaffold. + +This particular one is from +the Ingenuity database. + +You could get one from +any other database. + +You could get a consensus one +from three or four if you want. + +And so it has, up here, +extracellular stimuli, + +growth factors, cytokines. + +They're connected in their +interactome II receptors. + +They're connected to scaffolding +proteins and signaling proteins + +and kinases and so forth. + +They're connected to +transcription factors, + +metabolic enzymes. + +So you can draw this graph. + +Say this might be what's +going on in my cell. + +And then what we'd like +to do is to turn this + +into a formal logic +framework that's + +capable of then fitting +experimental data, + +predicting new +experimental data, + +and giving you a chance +at biological hypothesis + +and testing. + +All right, so +conceptually you get it? + +Two aspects-- some kind of +starting prior knowledge, + +that's kind of a scaffold, +a graph, for your network. + +And now you're going to turn it +into a computable logic model + +by mapping it against +empirical data. + +So, merely what it takes is +the kind of conceptual diagram + +you see in any cell biology +paper, any signaling paper, + +that says, well, a and b +both influence e positively, + +and b influences f negatively, +and c influences f positively. + +Then there's a +feedback from g to a. + +That's inhibitory. + +You can draw those. + +But now, how do you turn it +into a computable algorithm? + +So, what I'm going to spend +most of the day on is, + +just conversion of +this to a Boolean logic + +model that any one of these +interactions is and-- a and b + +being active makes e active. + +c being active, but +b not being active, + +allows f to be +active, and so forth. + +You turn these into +formal logic statements + +that you can compute on. + +At the very end, +if we have time, + +I'll show how to relax this from +a Boolean framework that's just + +on off, to something that +can be more quantitative. + +All right. + +So that's the notion. + +Now what I'm going to do +for the rest of the time + +is go through the specific +example paper that says, OK, + +how do we in fact do this? + +What is a way to +accomplish this? + +So now let's go back +to a biological problem + +where there's going to be +empirical, experimental data + +that we're now going +to map against one + +of these prior knowledge +interactome graphs. + +This particular study-- this was +done with Peter Sorger, who's + +now at Harvard Medical School-- +had to do with liver cells. + +Liver cancer-- you'll see +some application of that + +at the end-- that says we +have liver cell hepatocytes. + +And we want to know how they +respond to different growth + +factors, in cytokines +in their environment. + +How that'll change their +proliferation or death? + +Or the inflammatory +cytokines that they produce. + +And we'd like to take-- this is +just a pictorial diagram that + +could be in any +cell biology paper, + +and make this calculable. + +So we could say what's +different from a primary normal + +hepatocyte liver cell +that's not cancerous? + +It might have a signaling logic. + +But if then we compare +the signaling logic + +to a liver tumor cell type, or +four different liver tumor cell + +types, what's different? + +If we can find some logic that's +different for the tumor cell + +lines versus the normal primary +lines-- some logic from here + +to there or to there-- that now +tells you biologically, where + +the differences +might be that have + +arisen from the +genetic mutations. + +And where good drug +targets might be, + +or predictions if +I intervene here, + +if there's no difference in +that logic, between normal + +and tumor, well then that +won't have any effect. + +I want to look for +the places where + +there is a difference +in the signaling logic. + +And that would be a +better drug target. + +OK, so the measurements +are made in + +across 17 of these different +signaling molecules + +here, pretty much +all by measurement + +of a phosphorylation state. + +So if you've done cell +biology or biochemistry-- + +in these signaling +pathways, many + +of the activities in +these kinds of pathways + +that regulate this +kind of cell behavior + +are kinases that end up +affecting transcription factor + +activities and so forth. + +And it's the +phosphorylation state + +of any these proteins +that matters. + +If a phosphate is on some +particular amino acid, + +the enzyme might be active. + +If it's not there it might +be inactive and so forth. + +So, just measurement of +phosphorylation states + +of 17 different proteins +in these pathways + +distributed across +multiple pathways. + +I've made these measurements on +five different cell types, four + +tumor cell types, +and the primaries + +in order to try to see what's +different between primary + +and tumor. + +And then what might be +different, patient to patient. + +In response to seven different +extracellular stimuli, + +some of them growth +factors, some of them + +cytokines, some of them actually +bacterial metabolic products. + +We all know about the effects +of microbiome these days. + +And, to further +populate a database that + +might be capable +of helping validate + +a model, a number of seven, +in fact-- intercellular + +inhibitors. + +A small molecule, +these things in black. + +One that might +inhibit this kinase. + +One might inhibit that kinase. + +One might inhibit that kinase. + +So now if you add all +those inhibitors too, + +then you start to change +the network activities + +and the downstream behavior. + +So that's how +extensive the data is. + +And this is actually for a +few different time points. + +So the data looks +something like this. + +Let's focus on the +one on the left. + +This is just the primary, +normal, human cells. + +It came from a liver donor. + +OK. + +Each row is one of the +17 different signals, + +essentially measurement +of the phosphorylation + +state of Akt or CREB +or P52 of staph 3. + +OK? + +So measurements of +its phosphorylation + +state that has something to do +with its signaling activity. + +Each of the big columns are the +seven different treatments-- + +the different growth factors +and cytokines and so forth. + +And the control. + +No stimulation. + +And within each one +of these treatments, + +in each one of these +stimuli, then there's + +seven different +inhibitors that were + +used for the different pathways. + +So seven stimuli by seven +inhibitors plus controls. + +And then three +different time points. + +Sort of zero, 30 +minutes, and three hours. + +So the data looks +something like this. + +If there's really no change, +due to the stimulation + +or the inhibitor, you'll +see something in gray. + +So in these gray bars, +there was already + +phosphorylation of this +transcription factor + +[INAUDIBLE] and it didn't really +change under most treatments. + +If it was yellow, +what it meant was, + +whatever the treatment was, +you got a quick activation + +of that signal and +then it went away. + +If it's late-- purple, then it +didn't happen in the first half + +hour, but it started to +show up a few hours later. + +And if it's green it showed +up in the first half hour + +and it stayed sustained. + +So that's what the color means. + +But this is the real +experimental data. + +And over here on the right is +one of the tumor cell lines. + +And you can just +see by inspection, + +it's different, right. + +The colors here are different +from the colors there. + +All the same treatments, +stimuli inhibitors. + +The colors are very different. + +You know, therefore that +the signaling activities + +are very different. + +OK. + +Just by visual inspection. + +OK. + +So what we're going to try +to do is build a logic model + +for this. + +A logic model for this. + +Compare them and say, oh where +are the key differences in how + +the signaling pathways +are getting activated? + +Downstream of the same stimuli. + +So, we start with +our prior knowledge. + +This is from the Ingenuity +database, which actually + +happened to be missing, +even basic information + +about insulin signaling. + +So we just added +our own information + +about what the +insulin receptor does. + +It's kind of hard to believe. + +This is a database that +cost a lot of money + +and they didn't have +really much information + +about insulin +receptor signaling. + +Very strange. + +So, downstream of +our seven stimuli, + +down to the transcription +factors of interest, + +there are about 82 molecular +nodes and a hundred some edges + +that you'd pull out of +the Ingenuity database. + +So here's our starting guess +at what this looks like. + +There's no logic in here, but +this is just, potentially, + +the things that the +logic might operate on, + +downstream of stimuli, and +when inhibited, and so forth. + +All right. + +So here's the process. + +This was the actual +algorithmic process + +that I'll walk you through. + +On the left-hand side +is the computer part. + +It said, OK, from the +Ingenuity database, + +we had this prior +knowledge about who + +was upstream, downstream, +who affected whom. + +We strip this down +some, because in terms + +of the measurements +on the perturbations, + +there are some of the nodes +that you just would not + +be able to see any +measurable difference. + +OK, there was no stimulus +upstream, or no perturbation. + +And it was not +measured so you really + +wouldn't be able to tell +if it changed or not. + +So you just take those out. + +Of everything remaining, now +you don't know the logic. + +You know the potential. + +And so you say, well, of all +the nodes and interactions + +remaining, I could have AND +gates, I could have OR gates, + +you could have NOTS. + +And you say, OK, in +principle, I could have, + +then, many, many, many, +many, many different logic + +models that could work. + +So how do I know which one? + +Well now you skip +over to the other side + +and say, well, but we have +all this experimental data. + +We have the data from +all the different stimuli + +and all the different inhibitors +for any given cell type. + +And so, we have that data under +all these different conditions. + +And what we're +going to do is just + +run hundreds or thousands of +these potentially appropriate + +models. + +Compare them to the data of +whether any given node is + +activated or not, activated +under treatment conditions, + +stimuli inhibitors. + +And we'll calculate the air. + +How good was any +one of those models + +at actually matching those data? + +Simple as that. + +And then it's a +matter of finding + +what are the best fit ones +from the best fit ones. + +Could you improve them and +make them fit even better? + +And in the end, how did you go +from an initial prior knowledge + +scaffold to something that, in +fact, fit the data really well, + +from which you could +make new predictions. + +OK. + +So you get the approach here? + +All right, good. + +Now, in terms of figuring +out how well any given + +model matches the data and how +to go through model selection, + +there's a myriad of +different approaches to this. + +And I'm not claiming +that what we did + +was the absolute best approach. + +There's alternatives to +it that one could consider + +and then perhaps could +work even better. + +If you read the paper, +you'll read the reasons + +for these choices. + +OK. + +So I'll let you do that. + +The way the model +quality was calculated + +was to have an +objective function that + +said we want to minimize +some number, theta. + +And how do we calculate theta? + +Well, first of all, for +whatever that model is, + +we're going to fit-- whether +the model says some nodes + +should be on or +off, one or zero. + +And we're going to compare +it to the experimental data. + +Now the experimental +data, I need to emphasize, + +isn't one or zero, +it's normalized + +to go between one and zero. + +But the actual measurement +might be 0.7 or 0.25. + +OK, so you're going to have +error against the Boolean model + +even if all the edges are +absolutely correct you'll + +still going to get some +quantitative error. + +So you calculate that. + +The Boolean model +says zero or one. + +The experimental +data says 0.250, 0.7. + +And you say, OK, +I'll calculate that. + +But then you might +think, all right, well, + +somehow I've got to penalize +bigger models with more + +nodes and more edges because +surely the more nodes and edges + +I put in, I could +capture more of the data. + +And I don't want to make +the model infinitely large + +just to get the best fit. + +So I need to penalize that. + +Turns out it's not true, but +nonetheless it's worth doing. + +So, you take a parameter +that's the size of the model. + +It's basically just +the number of nodes. + +The more nodes in +it, the more you + +would be suspicious of +the model for just fitting + +because it has too +many components. + +And you multiply that size by +a penalty parameter, alpha. + +So you have a bad +objective function + +if there's a lot of +error with the data, + +or if your model's too big. + +A better model would be, better +fit to the data and smaller. + +That's the calculation. + +OK. + +And in the end-- and I'm going +to show you how we did this. + +And I think the field is +now really believing this. + +That what you're not after +is a single best fit model. + +That one single model that gives +you the very smallest data. + +Because honestly, +within the uncertainty + +of the experimental +data-- OK, there's + +a substantial number +of models that + +could fit the data +within that noise. + +So if you demanded +the single best one, + +you say, well, but +these other 50 actually + +fit it almost as good and within +the uncertainty of the data. + +How can you really reject them? + +And you can't. + +So in the end, what's +being striven for in most + +of the field is a +family of models. + +And then you see +what the consensus + +is and the differences +within that family. + +The particular algorithm +for generating and running + +through different +potential models-- + +because you just +can't exhaustively + +sample all of them. + +OK, these networks are so large, +that you can't exhaustively + +test all possibilities of +all their logic and so forth. + +It's really prohibitive. + +So there's many different +ways you can go about it. + +This particular method +maybe you've already + +learned this in class +for other applications + +as a genetic algorithm. + +So you start with +some population. + +You start with your +Ingenuity scaffold + +and then you randomly remove +or take edges and things + +like that. + +So that if you've +got a whole family, + +that's slightly different. + +For each one of them you +evaluate the objective function + +against the data. + +And you get some of those that +then are the most attractive. + +They seem to be the best fit. + +But, by no means would you +imagine they are yet optimal. + +So, now you create a next +generation from this population + +by the analog of genetics. + +Some of the very best-- +you say, OK, they're + +going to survive so I'm just +going to take them as is. + +Some I'm going to +mutate, I'm going + +to have a probability of +mutating an edge here or there. + +You can have crossover, +actually mating + +between one model +and another model, + +so that the daughter +model gets some + +of the arcs from the mother +model and some of the arcs + +from the father model. + +So you just generate an +ex-population, do it again. + +And once you've +reached a set of models + +that fit your data +within the criteria + +that you want, then you say, +this is now my population. + +And these are now +my best-fit models. + +So it's not exhaustive. + +You can definitely find +local minimum here. + +There's no question about that. + +Yeah? + +AUDIENCE: Do you always take the +best model into the next round? + +Or do you-- + +DOUG LAUFFENBURGER: Yeah, +that's the elite survival. + +If you don't +incorporate that, you + +might lose the best +ones in any given round. + +But this ensures you +take the best subset. + +Let them go for it. + +AUDIENCE: Is there +a worry that you + +might get stuck in [INAUDIBLE]? + +DOUG LAUFFENBURGER: Yes. + +Yes, absolutely. + +So now you run this with a +number of different starting + +populations. + +And you see if you get to +similar consensus models. + +Yeah, because +absolutely, this does not + +guarantee any kind +of a global minimum. + +You will always get local. + +So you have to condition +it on a different set + +of initial populations. + +OK. + +Once you do this-- I'm going +to show you some results + +first and then dig into some +other ways to think about it. + +So it's plotted here. + +This is one of the +tumor cell lines. + +What's plotted here, is again, +all the rows or all the signals + +that were measured. + +All the big columns or +all the different stimuli, + +and all the little columns +are the different inhibitors. + +And I should point out, this +is only for the 30 minute data. + +OK. + +This isn't for the +three hour or both, + +this is just the 30 minute data. + +And basically where +there's green, + +the model and data +fit was considered OK. + +Where it's red, it's not OK. + +Where it's pink it's less bad. + +So by the shaded. + +And the yellow +actually, the model + +really couldn't +make a prediction. + +Now, why that's the case +is what's showing up here + +is just the initial +Ingenuity scaffold. + +The very best one that +didn't add or remove any + +arcs or nodes from the +Ingenuity prior knowledge. + +It's that all we're +going to do is just + +run the best fit Boolean +logic model we can on that. + +And it wasn't very good. + +It was about 45% error. + +Almost half of the +nodes it got wrong. + +So what that tells you if you +just take a scaffold from one + +is interactive databases +and without adulterating it, + +just fit the best logic +model to some data-- + +OK, at least in this case, and +we've done a number of others, + +it actually doesn't +fit very well. + +And the reasons being, +you're trying to fit this now + +to a very specific +biological context. + +Hepatocyte tumor +cells under these + +grow factor and +cytokine treatments. + +That network is +likely very different + +from whatever aggregate you +got from literature curation + +and so forth in a database. + +There's going to be a lot of +stuff in the database that's + +not applicable, because it +came from a different cell + +type, a different +condition, or there just + +wasn't enough experiments in +the literature for hypatocytes. + +Maybe it was never +measured under treatment + +with interferon gamma. + +So there's data here +that the database never + +had access to literature +that it had explored. + +So lots of reasons. + +Now when you go through the +processes we just talked about, + +and in the end, +the best fit models + +give you something like +less than 10% error. + +So less than 10% of these +squares are red or pink. + +OK, so that's the +kind of improvement + +that you can take by +generating an improved model. + +By adding and subtracting +arcs and nodes. + +So this is what the model looks +like in the end for this tumor + +cell line. + +And this is a consensus model +from the 20 or so best fit. + +And so the thickness +of a line is + +how strong the consensus was. + +The strongest would +be all 20 had it. + +And the point here being, +you see some purple. + +And I wish my pen wasn't +fading in and out. + +If anybody has a pointer +I'll be happy to have it. + +Where you see purple, +those were arcs that + +weren't in the +Ingenuity database + +and had to be put in to get +the data to fit this well. + +And it turns out, +if you actually + +go back to the literature, you +find that those purple arcs + +were already described +in the literature. + +It's just that they weren't +captured in that database. + +Well that's green and purple. + +Then you see some +blue and they were + +in some of the other +tumor cell types + +but now in this +particular hep G2 + +But you can generate a +model that works very well. + +And see that it's consistent +with much of literature. + +It's a more stripped down +than what's in the databases. + +And there's some new +things in it, that in fact, + +if you go back to the +literature you can find, + +because they just were +captured in the database. + +All right. + +A few insights +about the analysis. + +So I want to show you, here +is the objective function. + +How well the model +fit and that's in red. + +OK. + +And in blue is the actual +fit to the experimental data. + +And again, the hirer +it is the worse it is. + +And the green gives you +essentially the size. + +And this is plotted +against the size penalty. + +And what's very interesting, +is even for very small size + +penalties, almost negligible, +that the size of the model that + +turns out to be best fit +is substantially smaller + +than what was in the database. + +OK, so you actually generate +a small model immediately. + +A smaller model immediately, +even without any size penalty. + +So your intuition +that a bigger model + +was going to be better actually +turns out to be incorrect. + +That even without a size +penalty, the model strips down. + +And why is that? + +Why is that? + +Let me make that +question number two. + +Just to see who's still awake. + +Why, in fitting this +hepatocyte data, + +would a model that leaves out +a lot of stuff in the Ingenuity + +database that's presumably +going on actually + +fit the data better? + +A smaller model fits better? + +Why is that? + +Yeah. + +AUDIENCE: This is a [INAUDIBLE]. + +Maybe the strength +of the attractions + +aren't really taken +into account here? + +And so the moving things +out, essentially means + +that you're not sealing +everything in the [INAUDIBLE]. + +You're just taking one. + +DOUG LAUFFENBURGER: Yeah. + +That's essentially it. + +I think you've casted it an +almost quantitative term, + +but I think it's true +even in qualitative terms. + +And one way to think +about it is-- let's + +say I have an extra +arc or extra node. + +OK. + +I might capture some +more true positives. + +I might actually +capture more of my data, + +but I could actually now, gain +more complex with my data. + +Because now I've put +in logic that, yes, + +it captures this +measurement, but now maybe it + +messes up these other two +or three measurements. + +So you actually can +make your model worse + +trying to capture some small +piece, that in fact, adversely + +influences the effects on +the other measurements. + +So you get you get false +positives, false negatives, + +along with anything +and that's true. + +And it just so happens that +in these kind of situations + +those can outweigh. + +Then of course, as you +increase the size penalty + +you can drive your model to +be even smaller, fewer arcs, + +and now that of course +does come at the expense + +of not fitting the data better. + +OK. + +So where we decided that +the size penalty best lived + +was where it was large enough +to ensure stripping down + +of nonessential nodes and +arcs, but not large enough + +to start compromising the +actual experimental fit. + +OK. + +And so that lived +someplace around there. + +OK. + +An important thing-- +and this goes back + +to the consensus model. + +If you think about, quote, +model identification, + +can you uniquely specify +one model a best fit model? + +You really can't. + +What's plotted here is +for any of the arcs that + +would end up in a model. + +Let's say we let's say we +numbered them from one to I + +think it was 113 +in the first place. + +One arc, another arc, +another arc, another arc. + +And you say, how +frequently did they + +end up in the best fit models? + +Basically, only a small +proportion of them + +were in all the best fit models. + +Some of them were in +some models and some not. + +Of course the higher +the tolerance, + +the more air you +allowed and now you + +started to get +models that all fit + +to within whatever that criteria +was in which most of their arcs + +weren't the same. + +You could have a lot of +different network structures + +that give you that same fit. + +If you require a very, very +tiny fit, compared to air, + +something like this, then +more of the arcs in the models + +have to be in common. + +OK. + +So that makes some sense. + +But you can't really completely +identify a unique model. + +That goes to what I said before. + +OK. + +I was talking before +about trade-offs + +between false positives +and false negatives. + +You must know, I'm sure from +previous things in this class, + +the receiver operating +characteristic curves, + +where for every of your +model parameter choices, + +you say, what are +my results in terms + +of false positives +versus true positives? + +And you're trying to +find the optimal location + +along this type of path. + +And so, what's shown here is +that the best predictive model, + +in fact, is the one where +we have the size penalty + +to be right on the edge of not +making the experimental data + +fit worse, but still +strips out the most arcs. + +So again, that demonstrates +that the smaller model actually + +is in fact better, in terms +of finding this type of-- + +And this shows if we actually +put in some more arcs that + +tried to capture some +more data, yes we decrease + +the false negatives, +but, in fact, we + +increase the false positives. + +We actually shift +ourselves on this curve. + +And so you decide whether +that's desirable or not. + +Where you'd like to live. + +So you can analyze what you +like about your best fit class + +of models in this kind of way. + +OK, so now we have some +confidence in this. + +What are you going +to do with it? + +And one thing I'd like to do is +just make a priori predictions. + +Say I now believe that on +these hepatocytes or tumor + +cells stimulated with +these kind of things, + +I can calculate what the +experimental signaling + +activities should be. + +All right. + +Let's see if we +do that a priori. + +So let's now use new inhibitors +that hadn't been used before. + +Combination of inhibitors, +especially in cancer. + +People are always interested +in combinatorial drugs. + +Experimentally it's +prohibitive to run + +through all possible +combinations. + +So this is one thing in +the pharmaceutical field + +people believe these kind of +models are really useful for. + +Let's try all possible +drug combinations + +and see which ones +are most promising. + +And instead of just one +ligand growth factor cytokine + +at a time, do +different combinations. + +So this is all an +entirely new data set. + +So different treatments that +are different combinations, + +different inhibitors, different +combinations of inhibitors. + +And now you just run the model-- +it's not trained on this. + +It was trained on +the previous data. + +And now a priori +predicts this data set. + +And now, again, you look for +the model fit in the bottom. + +And again, you want the smallest +number of red and pink boxes. + +In effect it predicted to +within about 11% error. + +About 11% of the boxes didn't +fit well, but 89% percent did. + +And that's, in fact +pretty close to the 9% + +that was on the +original training model. + +So in terms of this, in +this realm of studies, + +these a priori treatment +conditions-- drug combinations, + +growth factors, +cytokine combinations-- + +this is a pretty good validation +that this model wasn't + +just kind of trained and fit. + +That it, in fact, +could predict then + +what was happening +in these pathways. + +And then of course, what +it allows you to do, + +where all the red +boxes are-- it say, OK, + +that's where we need +more intensive study. + +Now maybe we go back to +the literature and say, + +is there more known +about those nodes that + +was captured in whatever +our interactive database + +that we started with? + +Maybe we need to supplement the +scaffold with more information. + +That's out in the literature +where more and more dedicated + +experiments are done. + +So it narrows down where the +next set of investigations + +need to be, whether from the +literature or from yourself. + +OK. + +So this is just then +some biological results. + +If you do this for the four +different hepatocellular lines. + +Some of the signaling +activities are the same, + +and some are different. + +I think I'll skip that. + +All right, let me show this. + +So this says, where are the +similarities and differences + +between the normal hepatocytes +versus the tumor lines. + +Because this is +where you would want + +to get the ideas for where +the right drugs would be. + +Where is the logic different, +between a normal liver + +cell and one of these +transformed types. + +So, this is the same +kind of scaffold. + +It'll get us the +consensus models + +and the thickness of +the line is how strong-- + +what proportion of the models +did that arc show up in? + +Along the best. + +If it's black, the arc was +in the primary hepatocytes + +and all the cell lines. + +So black is just sort +of consensus core. + +This is just invariably there. + +The blue was in the models +for the primary hepatocytes, + +but for some reason didn't +exist in the tumor cell lines. + +So we're signaling logic +that normal hepatocytes use, + +that the tumor cell +lines have somehow lost. + +Red, are arcs that weren't +in the primary cells, + +but showed up in the +tumor cell lines. + +So was logic that the normal +liver cells apparently + +didn't use, but now showed +up in the tumor cell lines. + +And why would there +be these differences? + +Well this is where it goes back +to then the genetic mutations + +and variations. + +Because going from a primary +to some tumor cell line, + +there's enough of the genetic +mutations, that in this case + +said, OK, I've got some genetic +mutation that interrupts + +the link between map +three kinase and Ikk. + +There was some docking +protein or something + +that's now missing, not +expressed as highly. + +It's got a mutation +of amino acids + +and no longer docks right. + +It has a lower +enzymatic activity. + +So now you can go +back and trace. + +Can I find some +genetic mutation that + +has to do with the +loss of that arc? + +Or if I've got a red +arc that shows up-- + +like I said because +there was something + +in my genetic mutations that +now adds an activity here + +that wasn't there. + +Maybe something is now +constituently active. + +Maybe something is just +expressed at a higher level. + +And all of a sudden that +pathway comes into play. + +So that's the cool thing. + +You can trace what's actually +in the genetic mutations + +if you have some +methodology for that, + +to what's actually been +altered in the network logic. + +Yeah? + +AUDIENCE: Are the primary +lines considered healthy lines? + +Or are they-- + +DOUG LAUFFENBURGER: Yes. + +AUDIENCE: OK, so the-- + +DOUG LAUFFENBURGER: Yeah. + +So they're from +donors but they're + +mainly like motorcycle accident +donors that don't either + +liver anymore but +the liver was fine. + +So, yeah, they're +from healthy donors. + +AUDIENCE: [INAUDIBLE]. + +DOUG LAUFFENBURGER: Yeah. + +Yeah. + +It was the lines at some +point came from a tumor + +and have been propagated +in a culture, yeah. + +OK. + +What do I want to-- got +a little bit more time. + +Let me do this. + +OK. + +So here's another interesting +thing that can happen. + +If you take these +models seriously, + +it can tell you something +about the biochemistry, perhaps + +of what's going on. + +So see there's this dashed line +here that I want to emphasize + +and we'll emphasize it +again on another slide. + +That was one that +had to be added. + +It just wasn't in the +Ingenuity pathway, scaffold. + +Actually couldn't find it +in any literature anywhere. + +But nonetheless you needed +it to fit some data. + +So we kind of kept +our eye on that one. + +What the heck is going on here? + +This dashed line from I kappa +kinase up to step three. + +No evidence for that signaling +linkage in the literature + +anywhere. + +What could that tell you? + +All right. + +Well, you go back to the +data now and you say, + +well what of the data set, of +the experimental measurements + +that we made, caused +that arc to have + +to be there to +fit the data well? + +OK. + +You can now ask that +kind of question. + +Well remember I said in the +data set were inhibitors. + +Some small molecule +inhibitors against this kinase + +or that kinase or that kinase +that would perturb the network + +and then give us relationships +at the logic model + +and had to account for. + +Well, this one had +to be there, mainly + +to account for data that came +from an inhibitor of Ikk. + +That one of the kinases +that we had a small molecule + +inhibitor for, +inhabited this kinase. + +And somehow there +turned out to be + +an effect on staph +3 phosphorylation. + +And so you needed +that arc to be there. + +So either the explanation +that either there's, + +in fact, some real +mechanism going on here. + +It might have been +transcriptional + +that somehow the +activity of this kinase + +affects the levels of expression +and the responsiveness + +of staph 3. + +Or you say, ah, maybe it's +a problem with the drug? + +It's a problem +with the inhibitor. + +That, in fact, what you thought +was an inhibitor that just + +affected this kinase, has +an off-target target effect + +on that kind of that kinase. + +And it's just an artifact. + +That's an alternative +explanation. + +Right, so that's the sort +of thing you can test. + +And we did test it. + +And here's the data here. + +At the bottom is the kinase that +you wanted the inhibition 2. + +And in the blue was the +inhibitor that was actually + +used in the study, both +in vivo and en vitro + +and it inhibited that kinase. + +But then we looked at the +potential off target effect + +on that other-- the +JAK2 [? stat ?] 3 + +and it also did have +activity on that. + +So it meant that +that inhibitor had + +an effect, not just on the Ikk, +but also on the JAK [? stat ?] + +3. + +And so that's why that +arc had to be there, + +is because, in fact, +that inhibitor, + +inhibited this kinase as well. + +So if we took that into account +in terms of the algorithm, + +then we wouldn't have to +have that arc because it + +was spurious and came +from the arc, in fact, + +of that inhibitor. + +But the interesting thing +is that, by taking the model + +seriously, we can +actually find that. + +Because it was not previously +known that this inhibitor had + +an off-target effect +on that kinase. + +In effect, the interesting +thing, pharmacologically, + +was that this +small molecule that + +was aimed to be an inhibitor +against this kinase + +was the best by far in treating +lung airway inflammation, + +compared against +a whole other set + +of other types of inhibitors +for the same kinase. + +So now the reason +might be is, it's + +better because it's also +hitting this other kinase. + +That this off-target +effect actually + +is therapeutically +efficacious and in fact + +a combination of drugs +against this kinase + +and the other kinase +is what's required + +for the therapeutic benefit. + +So that's something +that could be explored. + +And that's the sort of +thing this model leads to. + +OK. + +Let me end by digging into +this difference a little bit. + +Because I said, you +see these differences + +between primary hepatocytes +and the tumor cell lines. + +And the model said, just +from examining the data sets, + +that the logic is different. + +OK. + +Is there any +validation for that? + +Well, so let's go back and +look at those differences + +with respect to literature. + +So if you just blow up +that part of the model, + +there's eight edges +that are strongly + +disparate between the primary, +normal cell types and the tumor + +cells and they're +all enumerated here. + +One, two, three, four, +five, six, seven, eight. + +And they're essentially in +three different pathways. + +So what the model +is telling you is + +that there's three different +pathways that are substantially + +different between a normal liver +cell and a liver tumor cell. + +OK. + +So is there any evidence +that this is really true? + +So let's look at one. + +On to this pathway that +I've got differences. + +And you see blue +here and red here. + +It says that this particular +signaling node in normal cells + +is activated by this pathway. + +In the tumors, that +regulation is lost + +and that actually comes +through another pathway. + +And it turns this is +consistent with literature + +that, in fact, in +the tumor cells, + +you get a higher activity +of this downstream node. + +And now I've lost +my light again. + +This HSP27. + +Even though it's +over expressed, you + +get less activation because +this pathway is less strongly + +activated in red than +the blue pathway is. + +So if you went by +gene expression, + +you'd think in the +tumor cells, this + +is a higher activated pathway. + +Turns out the +logic is different, + +and you actually get +less activation of it + +because it's coming from +a different pathway. + +So that turns out to be true +in the liver tumor literature. + +Another one-- I find this +one really interesting. + +That in normal liver cells, +to activate this Ikk pathway-- + +that's a very important +kinase pathway, + +governing the transcription +factor of NF Kappa b. + +In a primary cell, I +need this combined logic + +between a pathway downstream +of insulin receptor + +and a pathway downstream +of a cytokine. + +Only if both of those pathways +are on, do I now turn this on. + +In the tumor cells, +that check is lost. + +Only one pathway is required. + +OK. + +If this one is +activated, I'm going + +to get this transcription +factor activated. + +I don't have to wait for +simultaneous activation + +of this pathway. + +Where as a normal +says I have to. + +OK. + +That turns out to be true +that in the liver cells, + +the progression is +associated with a looser + +regulation of this +transcription factor. + +And one more. + +I won't go into too much +detail, but again, you + +see reds and blues here. + +In the tumor cell +lines, you've now + +got activities +downstream of insulin. + +That's normally just +a survival factor, + +that's just not found +in the primary cells. + +And that, in fact, is shown +in the literature too, + +that insulin signaling +shifts from metabolism + +to proliferation. + +It's mainly metabolic, stimulus. + +In the normal cells it turns +into a proliferative stimulus + +in the tumor cells. + +OK. + +So, what this says is, +just by mapping this logic + +scaffold, the scaffold +against empirical data, + +developing a logic +model, you in fact + +can find loci of differences +between the normal cell + +signaling logic and tumor +cells signalling logic + +for which there's evidence in +the literature, none of which + +was in the original databases. + +Finally, I'm going +I'm just going + +to say that it turns out in +another study, what you could + +show is those three pathways +that the model predicts + +are the differences +between the liver tumor + +cells and the normal cells. + +That in order to kill +these liver tumor cells, + +you need inhibitors against all +three pathways simultaneously. + +You actually need +combination drugs + +of three different pathway +inhibitors to kill these cells. + +And it's exactly +the three pathways + +that the model predicted of the +differences between the normals + +and the tumor cells. + +OK. + +All right, so I will +end here and then see + +if there's any more questions. + +Something that +comes up a lot is-- + +there's discomfort with Boolean +logic because of zero, one. + +It's off, on, and of +course we know biology, + +biochemistry doesn't +work that way. + +And so there can be +so many artifacts, + +so many places that you +can get things wrong, + +because you're trying to fit a +model where the measurement is + +supposed to be +either zero or one, + +and you're comparing it +against a measurement that + +might be 0.6. + +Well, 0.6, is that closer +to 1, is it closer to 0? + +Is there some normalization +that would shift it + +from one to the other. + +And instead of being a correct +fit, it's now an incorrect fit. + +So you can see the +room for artifacts + +by mapping quantitative data +against a qualitative model. + +So, one thing done more +recently is to admit that + +and say, well, let's say +just relax this a bit. + +And instead of having step +functions from off to on, + +that they're more graded. + +It's like an analog +transfer function. + +So what you've essentially +done is add one more parameter + +to every node, to every gate. + +Because of Boolean +logic, there's + +essentially one +hidden parameter. + +That's where you shift +from off to on, right? + +There's some location of +the level of the signal + +that you've decided is 0 or 1. + +So there's some parameter +that you shift from, + +saying it's off to on. + +Well here now in this +formalism there's that, + +but there's also then the slope +of shifting from off to on. + +Is it still fairly steep? + +Is it really mild? + +Is it someplace in between? + +OK? + +And this can go with +AND and OR gates too. + +Now, instead of +just one dimension, + +one component being +off to on or on to off, + +now you got AND and OR gates +that have these slopes as well. + +So what this means is +you require more data + +to fit this-- we call it a +constrained fuzzy logic model + +because you've got-- if I've +got 50 nodes in my system, + +I've got 50 more +parameters I've got to fit. + +OK, so that requires more data. + +What's the benefit of it, is +that your predictions now, + +in fact, can be quantitative. + +So you can go into +the model and say + +here's a transcription +factor CREB. + +I'm going to predict its +phosphorylation state + +and its transcriptional +activity, perhaps, + +based on the activities +of two upstream kinases. + +And so if I had had an inhibitor +for one of these kinases + +or another, how much would +I shift the phosphorylation + +of this transcription factor? + +And what you actually see is +these gradual curves, that if I + +start to inhibit +[INAUDIBLE], OK, it gradually + +changes the +phosphorylation of CREB. + +Or if I inhibit the +activity of P38, + +it even more gradually +effects the activity of CREB. + +So you can turn these into +quantitative predictions + +of strong effects, weak effects. + +And again, look at +drug combinations. + +So that's the advantage of going +to this more analog transfer + +function logic model. + +You can deal with +quantification much better, + +but at the cost of +requiring more data. + +OK, I think I'll leave it here. + +It's about 3:15 +and so if there's + +more questions we can take +them about any aspect of this. + +Most of you have stayed awake, +I think that's a good thing. + +OK. + +More questions? + +AUDIENCE: [INAUDIBLE]. + +When you have the model for +the template of the Ikk story. + +And then it seems +like it may not + +be as easy to back out +the original data that + +led to that specific mode. + +For example, you +showed that one arc + +was from this one treatment. + +But because if you trained +the model the same as that + +and it's not deterministic, +then what-- could you just add-- + +DOUG LAUFFENBURGER: I think +that's a great question. + +So let's say there's +new arcs that you add, + +that weren't in the +original scaffold. + +I mean that's what you got +the biggest questions from. + +If you delete one, +you say, ah, it's + +easy to believe why +you would delete one. + +Any arc that you add +to get a best fit, + +I think you've got to +ask questions about. + +So in all those +cases where there + +are arcs that were added that +led to a better fit model, + +the first thing we did +was go to the literature. + +Say, OK, is there literature +on some affect of this node + +to that node? + +And it's just that +that literature + +wasn't curated +into that database + +or something like that. + +And most of the time +we could find it there. + +OK. + +So then there were the cases, +and this was the most prominent + +one, where from some +added arc, we just + +couldn't find it +in the literature. + +In this particular +case, it was very + +easy to trace it to +this particular effect + +of this inhibitor. + +I would say there's no reason +to believe that that's always + +going to be the case. + +I don't have another example to +show you where it was harder. + +Everything else we actually +found in the literature. + +But you could imagine, having +some new arc that you really + +couldn't find in the +literature and there's + +no artifactual +explanation for it. + +And now, how you trace it +back to what the data was + +that might give you +a more nuanced hint. + +It's a great question. + +I don't really know +how we'll do that. + +I think, we and other +practitioners who use this, + +I'm sure we'll run +into it at some point. + +That's a great challenge +to be thinking about. + +Yeah? + +AUDIENCE: I might have +missed this earlier, + +but I was wondering, +is this model actually + +able to incorporate the +heterogeneity of a tumor, + +for example? + +Or the population heterogeneity? + +DOUG LAUFFENBURGER: That's also +a really interesting question. + +Let me try to show +something here. + +Yeah. + +So two things. + +One is, what's shown here-- +this is the four different tumor + +cells that we did. + +And what's shown in color is +the arcs for each one of them. + +So yellow, orange, brown, red. + +So some places you see all +four of those colors there. + +In some places only two or one. + +It says if I had four +different tumor types, + +there's some slight differences +in logic among them. + +You could translate +to that is, well + +I could imagine +then having a tumor + +that's a mixture of sub types +and how would I discern that? + +One possible idea that's +attractive to me-- + +although we didn't really +explore this in any form of + +[INAUDIBLE]. + +We didn't really have +the means to make + +experimental +measurements on the tumor + +heterogeneity at the time. + +It's when you get to a +set of consensus models. + +Right. + +So let's say you get the 50 +best fit models and you say, + +some arc is in 80% of them, +but it's not in 20% of them, + +is it possible that +that represents + +some of heterogeneity +because you're + +getting an average of +different subtypes? + +I don't know. + +Sometimes that appeals to +me as potentially valid. + +Sometimes I think there's +a flaw in that reasoning. + +Just because you get an average +that's not then as strong. + +Does that necessarily +reflect a sub-population? + +I don't know. + +So what we do know is, +we can see differences + +when there are differences. + +How you actually see +them then, if all you + +have is averaged +data, maybe it's + +reflected in the heterogeneity +of the consensus models. + +Maybe not. + +It would be an +interesting to explore. + +Anybody else? + +All right. + +All set. + +Thanks. \ No newline at end of file diff --git a/iMDKTNDBSxE.txt b/iMDKTNDBSxE.txt new file mode 100644 index 0000000000000000000000000000000000000000..fb8d0638c6ead39b64facc8425966969abf57e43 --- /dev/null +++ b/iMDKTNDBSxE.txt @@ -0,0 +1,323 @@ +align:start position:0% + +a web-based program that will provide + + align:start position:0% +a web-based program that will provide + + + align:start position:0% +a web-based program that will provide +free access to primary materials for + + align:start position:0% +free access to primary materials for + + + align:start position:0% +free access to primary materials for +virtually every + + align:start position:0% +virtually every + + + align:start position:0% +virtually every +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +course when we have some number of + + align:start position:0% +course when we have some number of + + + align:start position:0% +course when we have some number of +equations say n equations and N unknown + + align:start position:0% +equations say n equations and N unknown + + + align:start position:0% +equations say n equations and N unknown +the the placebo and people who got the + + align:start position:0% +the the placebo and people who got the + + + align:start position:0% +the the placebo and people who got the +pill if they were not any me + + align:start position:0% +pill if they were not any me + + + align:start position:0% +pill if they were not any me +before are some small what's a a natural + + align:start position:0% +before are some small what's a a natural + + + align:start position:0% +before are some small what's a a natural +um what's a what's a reasonable way of + + align:start position:0% +um what's a what's a reasonable way of + + + align:start position:0% +um what's a what's a reasonable way of +proceeding here right what's a + + align:start position:0% +proceeding here right what's a + + + align:start position:0% +proceeding here right what's a +reasonable + + align:start position:0% + + + + align:start position:0% + +way I live in s Paulo Brazil where I go + + align:start position:0% +way I live in s Paulo Brazil where I go + + + align:start position:0% +way I live in s Paulo Brazil where I go +to medical school and I started using + + align:start position:0% +to medical school and I started using + + + align:start position:0% +to medical school and I started using +ocw when I was 15 I guess and I + + align:start position:0% +ocw when I was 15 I guess and I + + + align:start position:0% +ocw when I was 15 I guess and I +discovered ocw on YouTube about 5 years + + align:start position:0% +discovered ocw on YouTube about 5 years + + + align:start position:0% +discovered ocw on YouTube about 5 years +ago I absolutely love MIT open course it + + align:start position:0% +ago I absolutely love MIT open course it + + + align:start position:0% +ago I absolutely love MIT open course it +lowered the bar of entering a new + + align:start position:0% +lowered the bar of entering a new + + + align:start position:0% +lowered the bar of entering a new +learning territory for me and It + + align:start position:0% +learning territory for me and It + + + align:start position:0% +learning territory for me and It +ultimately allowed me to carve out a + + align:start position:0% +ultimately allowed me to carve out a + + + align:start position:0% +ultimately allowed me to carve out a +unique career pathway during the + + align:start position:0% +unique career pathway during the + + + align:start position:0% +unique career pathway during the +covid-19 pandemic I was unemployed I + + align:start position:0% +covid-19 pandemic I was unemployed I + + + align:start position:0% +covid-19 pandemic I was unemployed I +started as a poet and a painter and a + + align:start position:0% +started as a poet and a painter and a + + + align:start position:0% +started as a poet and a painter and a +sculptor I made the transition to + + align:start position:0% +sculptor I made the transition to + + + align:start position:0% +sculptor I made the transition to +working for a financial technology + + align:start position:0% +working for a financial technology + + + align:start position:0% +working for a financial technology +startup ocw allowed me to gain a more + + align:start position:0% +startup ocw allowed me to gain a more + + + align:start position:0% +startup ocw allowed me to gain a more +solid grasp on the basic Sciences it's + + align:start position:0% +solid grasp on the basic Sciences it's + + + align:start position:0% +solid grasp on the basic Sciences it's +helped me learn about the things I love + + align:start position:0% +helped me learn about the things I love + + + align:start position:0% +helped me learn about the things I love +learning about human Behavioral Sciences + + align:start position:0% +learning about human Behavioral Sciences + + + align:start position:0% +learning about human Behavioral Sciences +psychology programming and python + + align:start position:0% +psychology programming and python + + + align:start position:0% +psychology programming and python +thermodynamics just absolutely + + align:start position:0% +thermodynamics just absolutely + + + align:start position:0% +thermodynamics just absolutely +fascinating artificial intelligence then + + align:start position:0% +fascinating artificial intelligence then + + + align:start position:0% +fascinating artificial intelligence then +you should also start your Learning + + align:start position:0% +you should also start your Learning + + + align:start position:0% +you should also start your Learning +Journey with MIT open courseware and I + + align:start position:0% +Journey with MIT open courseware and I + + + align:start position:0% +Journey with MIT open courseware and I +think we probably should bring one more + + align:start position:0% +think we probably should bring one more + + + align:start position:0% +think we probably should bring one more +friend for the ride so we can reach 10 + + align:start position:0% +friend for the ride so we can reach 10 + + + align:start position:0% +friend for the ride so we can reach 10 +million + + align:start position:0% + + + + align:start position:0% + +soon + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +[Music] \ No newline at end of file diff --git a/iPWIqjYkVns.txt b/iPWIqjYkVns.txt new file mode 100644 index 0000000000000000000000000000000000000000..053dbf81b768397e8f217fd216f11da1b0a12112 --- /dev/null +++ b/iPWIqjYkVns.txt @@ -0,0 +1,12360 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +to view additional materials from + + align:start position:0% +to view additional materials from + + + align:start position:0% +to view additional materials from +hundreds of MIT courses visit MIT open + + align:start position:0% +hundreds of MIT courses visit MIT open + + + align:start position:0% +hundreds of MIT courses visit MIT open +courseware at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu okay let us + + align:start position:0% +ocw.mit.edu okay let us + + + align:start position:0% +ocw.mit.edu okay let us +start so last + + align:start position:0% +start so last + + + align:start position:0% +start so last +time we finished uh + + align:start position:0% +time we finished uh + + + align:start position:0% +time we finished uh +discussing conation + + align:start position:0% +discussing conation + + + align:start position:0% +discussing conation +of closed + + align:start position:0% +of closed + + + align:start position:0% +of closed +string and open + + align:start position:0% +string and open + + + align:start position:0% +string and open +strings and we + + align:start position:0% +strings and we + + + align:start position:0% +strings and we +see we saw that + + align:start position:0% +see we saw that + + + align:start position:0% +see we saw that +um if you want to + + align:start position:0% +um if you want to + + + align:start position:0% +um if you want to +quantize + + align:start position:0% +quantize + + + align:start position:0% +quantize +Strings + + align:start position:0% +Strings + + + align:start position:0% +Strings +consistently in a minkovsky space + + align:start position:0% +consistently in a minkovsky space + + + align:start position:0% +consistently in a minkovsky space +time then you need 26 + + align:start position:0% +time then you need 26 + + + align:start position:0% +time then you need 26 +Dimensions okay we also saw that when + + align:start position:0% +Dimensions okay we also saw that when + + + align:start position:0% +Dimensions okay we also saw that when +you quantize the photon oh when you + + align:start position:0% +you quantize the photon oh when you + + + align:start position:0% +you quantize the photon oh when you +contest open strings then you see a + + align:start position:0% +contest open strings then you see a + + + align:start position:0% +contest open strings then you see a +vector field a massless vector field in + + align:start position:0% +vector field a massless vector field in + + + align:start position:0% +vector field a massless vector field in +the + + align:start position:0% +the + + + align:start position:0% +the +Spectrum uh plus a infinite number of + + align:start position:0% +Spectrum uh plus a infinite number of + + + align:start position:0% +Spectrum uh plus a infinite number of +massive modes and when you quantize + + align:start position:0% +massive modes and when you quantize + + + align:start position:0% +massive modes and when you quantize +close strings then you see a mass spin + + align:start position:0% +close strings then you see a mass spin + + + align:start position:0% +close strings then you see a mass spin +two particles which is a + + align:start position:0% +two particles which is a + + + align:start position:0% +two particles which is a +graviton in your massive Spectrum plus + + align:start position:0% +graviton in your massive Spectrum plus + + + align:start position:0% +graviton in your massive Spectrum plus +infinite number of massive modes + + align:start position:0% + + + + align:start position:0% + +okay so that essentially uh is the + + align:start position:0% +okay so that essentially uh is the + + + align:start position:0% +okay so that essentially uh is the +essence of Str theory is that the stren + + align:start position:0% +essence of Str theory is that the stren + + + align:start position:0% +essence of Str theory is that the stren +series contains graviton in a quantum + + align:start position:0% +series contains graviton in a quantum + + + align:start position:0% +series contains graviton in a quantum +mechanical way um so should be + + align:start position:0% +mechanical way um so should be + + + align:start position:0% +mechanical way um so should be +consistent should be considered as a + + align:start position:0% +consistent should be considered as a + + + align:start position:0% +consistent should be considered as a +theory of quantum + + align:start position:0% +theory of quantum + + + align:start position:0% +theory of quantum +gravity so today we start talking about + + align:start position:0% +gravity so today we start talking about + + + align:start position:0% +gravity so today we start talking about +lot object in string theory it's called + + align:start position:0% +lot object in string theory it's called + + + align:start position:0% +lot object in string theory it's called +Uh a + + align:start position:0% + + + + align:start position:0% + +dein okay so we discussed open strings + + align:start position:0% +dein okay so we discussed open strings + + + align:start position:0% +dein okay so we discussed open strings +so let's go back to the open + + align:start position:0% +so let's go back to the open + + + align:start position:0% +so let's go back to the open +string for the open + + align:start position:0% +string for the open + + + align:start position:0% +string for the open +string say after we fixed the work sheet + + align:start position:0% +string say after we fixed the work sheet + + + align:start position:0% +string say after we fixed the work sheet +to be + + align:start position:0% + + + + align:start position:0% + +flat then work sheet action can be + + align:start position:0% +flat then work sheet action can be + + + align:start position:0% +flat then work sheet action can be +written as the + + align:start position:0% + + + + align:start position:0% + +following + + align:start position:0% +following + + + align:start position:0% +following +okay so you can when you get the when + + align:start position:0% +okay so you can when you get the when + + + align:start position:0% +okay so you can when you get the when +you obtain the equation motion for + + align:start position:0% + + + + align:start position:0% + +X say you + + align:start position:0% +X say you + + + align:start position:0% +X say you +will then have something like + + align:start position:0% +will then have something like + + + align:start position:0% +will then have something like +this so you need to do integration by + + align:start position:0% + + + + align:start position:0% + +part plus a total derivative term okay + + align:start position:0% +part plus a total derivative term okay + + + align:start position:0% +part plus a total derivative term okay +plus a total derivative term and total + + align:start position:0% +plus a total derivative term and total + + + align:start position:0% +plus a total derivative term and total +dtive term we we induce a term on the + + align:start position:0% +dtive term we we induce a term on the + + + align:start position:0% +dtive term we we induce a term on the +boundary if you have open + + align:start position:0% + + + + align:start position:0% + +string say at Sigma equal to Z and + + align:start position:0% +string say at Sigma equal to Z and + + + align:start position:0% +string say at Sigma equal to Z and +Pi + + align:start position:0% +Pi + + + align:start position:0% +Pi +okay so um + + align:start position:0% +okay so um + + + align:start position:0% +okay so um +so this is still + + align:start position:0% +so this is still + + + align:start position:0% +so this is still +detal and uh so + + align:start position:0% + + + + align:start position:0% + +um so from this term you get the + + align:start position:0% +um so from this term you get the + + + align:start position:0% +um so from this term you get the +equation + + align:start position:0% +equation + + + align:start position:0% +equation +motion and then you induce a boundary + + align:start position:0% +motion and then you induce a boundary + + + align:start position:0% +motion and then you induce a boundary +term evaluate + + align:start position:0% +term evaluate + + + align:start position:0% +term evaluate +it because open string there two + + align:start position:0% +it because open string there two + + + align:start position:0% +it because open string there two +boundaries at zero and + + align:start position:0% +boundaries at zero and + + + align:start position:0% +boundaries at zero and +Pi then you do such a boundary term at + + align:start position:0% +Pi then you do such a boundary term at + + + align:start position:0% +Pi then you do such a boundary term at +the boundary we need to um also get rid + + align:start position:0% +the boundary we need to um also get rid + + + align:start position:0% +the boundary we need to um also get rid +of + + align:start position:0% +of + + + align:start position:0% +of +otherwise uh the equation motion is not + + align:start position:0% +otherwise uh the equation motion is not + + + align:start position:0% +otherwise uh the equation motion is not +satisfied and uh what we discuss is soal + + align:start position:0% +satisfied and uh what we discuss is soal + + + align:start position:0% +satisfied and uh what we discuss is soal +Luman boundary conditions is just take + + align:start position:0% +Luman boundary conditions is just take + + + align:start position:0% +Luman boundary conditions is just take +the partti of Sigma equal to zero P + + align:start position:0% +the partti of Sigma equal to zero P + + + align:start position:0% +the partti of Sigma equal to zero P +Sigma X mu to be zero but in general for + + align:start position:0% +Sigma X mu to be zero but in general for + + + align:start position:0% +Sigma X mu to be zero but in general for +any + + align:start position:0% +any + + + align:start position:0% +any +mu say for any + + align:start position:0% +mu say for any + + + align:start position:0% +mu say for any +mu you have a choice of four boundary + + align:start position:0% +mu you have a choice of four boundary + + + align:start position:0% +mu you have a choice of four boundary +conditions you can choose Del X mu equal + + align:start position:0% +conditions you can choose Del X mu equal + + + align:start position:0% +conditions you can choose Del X mu equal +to + + align:start position:0% +to + + + align:start position:0% +to +zero or how should see Sigma X mual + + align:start position:0% +zero or how should see Sigma X mual + + + align:start position:0% +zero or how should see Sigma X mual +to0 + + align:start position:0% +to0 + + + align:start position:0% +to0 +say at Sigma equal + + align:start position:0% +say at Sigma equal + + + align:start position:0% +say at Sigma equal +to0 and you have the similar choices at + + align:start position:0% +to0 and you have the similar choices at + + + align:start position:0% +to0 and you have the similar choices at +Sigma equal to + + align:start position:0% +Sigma equal to + + + align:start position:0% +Sigma equal to +Pi so all together you have actually + + align:start position:0% +Pi so all together you have actually + + + align:start position:0% +Pi so all together you have actually +Four + + align:start position:0% +Four + + + align:start position:0% +Four +possible four possible boundary + + align:start position:0% +possible four possible boundary + + + align:start position:0% +possible four possible boundary +conditions for each Direction so for + + align:start position:0% +conditions for each Direction so for + + + align:start position:0% +conditions for each Direction so for +each Direction you have four possible + + align:start position:0% +each Direction you have four possible + + + align:start position:0% +each Direction you have four possible +boundary conditions if you can see the + + align:start position:0% +boundary conditions if you can see the + + + align:start position:0% +boundary conditions if you can see the +all possible directions there are many + + align:start position:0% +all possible directions there are many + + + align:start position:0% +all possible directions there are many +many different boundary conditions okay + + align:start position:0% +many different boundary conditions okay + + + align:start position:0% +many different boundary conditions okay +they in principle many many different + + align:start position:0% +they in principle many many different + + + align:start position:0% +they in principle many many different +boundary + + align:start position:0% +boundary + + + align:start position:0% +boundary +conditions so let's now look at what the + + align:start position:0% +conditions so let's now look at what the + + + align:start position:0% +conditions so let's now look at what the +other boundary conditions mean okay we + + align:start position:0% +other boundary conditions mean okay we + + + align:start position:0% +other boundary conditions mean okay we +look at the case which is the you just + + align:start position:0% +look at the case which is the you just + + + align:start position:0% +look at the case which is the you just +impose this + + align:start position:0% +impose this + + + align:start position:0% +impose this +everywhere at both Sigma equal to Z and + + align:start position:0% +everywhere at both Sigma equal to Z and + + + align:start position:0% +everywhere at both Sigma equal to Z and +sigma equal to Pi and for all directions + + align:start position:0% +sigma equal to Pi and for all directions + + + align:start position:0% +sigma equal to Pi and for all directions +but now let us explore uh this more + + align:start position:0% +but now let us explore uh this more + + + align:start position:0% +but now let us explore uh this more +General boundary + + align:start position:0% +General boundary + + + align:start position:0% +General boundary +conditions first + + align:start position:0% +conditions first + + + align:start position:0% +conditions first +let's just quickly look at what this B + + align:start position:0% +let's just quickly look at what this B + + + align:start position:0% +let's just quickly look at what this B +so so this is called the rich boundary + + align:start position:0% +so so this is called the rich boundary + + + align:start position:0% +so so this is called the rich boundary +condition this is called Lum so first + + align:start position:0% +condition this is called Lum so first + + + align:start position:0% +condition this is called Lum so first +let's look at what does this boundary + + align:start position:0% +let's look at what does this boundary + + + align:start position:0% +let's look at what does this boundary +condition mean + + align:start position:0% + + + + align:start position:0% + +okay so if we have say let's consider + + align:start position:0% +okay so if we have say let's consider + + + align:start position:0% +okay so if we have say let's consider +some direction + + align:start position:0% +some direction + + + align:start position:0% +some direction +I say Delta x i equal to + + align:start position:0% + + + + align:start position:0% + +zero say at Sigma equal to zero + + align:start position:0% +zero say at Sigma equal to zero + + + align:start position:0% +zero say at Sigma equal to zero +say t equal to + + align:start position:0% +say t equal to + + + align:start position:0% +say t equal to +zero so this is the example of this say + + align:start position:0% +zero so this is the example of this say + + + align:start position:0% +zero so this is the example of this say +der boundary condition in I Direction + + align:start position:0% +der boundary condition in I Direction + + + align:start position:0% +der boundary condition in I Direction +so suppose at Sigma equal to zero you + + align:start position:0% +so suppose at Sigma equal to zero you + + + align:start position:0% +so suppose at Sigma equal to zero you +have you impose + + align:start position:0% +have you impose + + + align:start position:0% +have you impose +this so what this + + align:start position:0% +this so what this + + + align:start position:0% +this so what this +means is said the variation of x i at + + align:start position:0% +means is said the variation of x i at + + + align:start position:0% +means is said the variation of x i at +Sigma equal to zero at all time does not + + align:start position:0% +Sigma equal to zero at all time does not + + + align:start position:0% +Sigma equal to zero at all time does not +change so T is like parameterize your W + + align:start position:0% +change so T is like parameterize your W + + + align:start position:0% +change so T is like parameterize your W +sheet a Time the W sheet + + align:start position:0% +sheet a Time the W sheet + + + align:start position:0% +sheet a Time the W sheet +motion so this tells you that at all + + align:start position:0% +motion so this tells you that at all + + + align:start position:0% +motion so this tells you that at all +time the value of the X side does not + + align:start position:0% +time the value of the X side does not + + + align:start position:0% +time the value of the X side does not +change at the end point so what this + + align:start position:0% +change at the end point so what this + + + align:start position:0% +change at the end point so what this +means this directly translate into x + + align:start position:0% +means this directly translate into x + + + align:start position:0% +means this directly translate into x +i Sigma = to zero and T should be a + + align:start position:0% +i Sigma = to zero and T should be a + + + align:start position:0% +i Sigma = to zero and T should be a +constant okay should be a + + align:start position:0% +constant okay should be a + + + align:start position:0% +constant okay should be a +constant so this is the dtive + + align:start position:0% + + + + align:start position:0% + +condition and so let's look at some + + align:start position:0% +condition and so let's look at some + + + align:start position:0% +condition and so let's look at some +examples to understand a little bit more + + align:start position:0% +examples to understand a little bit more + + + align:start position:0% +examples to understand a little bit more +explicitly what what this a kind of + + align:start position:0% +explicitly what what this a kind of + + + align:start position:0% +explicitly what what this a kind of +condition uh what this the condition + + align:start position:0% +condition uh what this the condition + + + align:start position:0% +condition uh what this the condition +means okay so let's first consider a + + align:start position:0% +means okay so let's first consider a + + + align:start position:0% +means okay so let's first consider a +example say + + align:start position:0% +example say + + + align:start position:0% +example say +suppose in all + + align:start position:0% +suppose in all + + + align:start position:0% +suppose in all +directions say from zero to D minus + + align:start position:0% +directions say from zero to D minus + + + align:start position:0% +directions say from zero to D minus +2 okay we + + align:start position:0% +2 okay we + + + align:start position:0% +2 okay we +use + + align:start position:0% +use + + + align:start position:0% +use +suppose uh uh uh + + align:start position:0% +suppose uh uh uh + + + align:start position:0% +suppose uh uh uh +use new boundary condition uh uh that's + + align:start position:0% +use new boundary condition uh uh that's + + + align:start position:0% +use new boundary condition uh uh that's +what we be for uh for + + align:start position:0% +what we be for uh for + + + align:start position:0% +what we be for uh for +both Sigma equal to zero and + + align:start position:0% +both Sigma equal to zero and + + + align:start position:0% +both Sigma equal to zero and +Pi but for the last + + align:start position:0% +Pi but for the last + + + align:start position:0% +Pi but for the last +coordinate so X D minus + + align:start position:0% +coordinate so X D minus + + + align:start position:0% +coordinate so X D minus +one okay so let's impose the uh the Der + + align:start position:0% +one okay so let's impose the uh the Der + + + align:start position:0% +one okay so let's impose the uh the Der +boundary condition say let's take it to + + align:start position:0% +boundary condition say let's take it to + + + align:start position:0% +boundary condition say let's take it to +be a at Sigma both Sigma and 0al to Pi + + align:start position:0% +be a at Sigma both Sigma and 0al to Pi + + + align:start position:0% +be a at Sigma both Sigma and 0al to Pi +okay so for the for the moment let's + + align:start position:0% +okay so for the for the moment let's + + + align:start position:0% +okay so for the for the moment let's +take the boundary to be same at both + + align:start position:0% +take the boundary to be same at both + + + align:start position:0% +take the boundary to be same at both +Sigma equal to 0 and + + align:start position:0% + + + + align:start position:0% + +Pi so let's look at what this condition + + align:start position:0% +Pi so let's look at what this condition + + + align:start position:0% +Pi so let's look at what this condition +means okay let's look at this + + align:start position:0% + + + + align:start position:0% + +example so what this condition + + align:start position:0% +example so what this condition + + + align:start position:0% +example so what this condition +means so let's draw a + + align:start position:0% + + + + align:start position:0% + +figure so I cannot draw many directions + + align:start position:0% +figure so I cannot draw many directions + + + align:start position:0% +figure so I cannot draw many directions +in particular cannot draw 626 + + align:start position:0% +in particular cannot draw 626 + + + align:start position:0% +in particular cannot draw 626 +Dimensions so let me call the horizontal + + align:start position:0% +Dimensions so let me call the horizontal + + + align:start position:0% +Dimensions so let me call the horizontal +axis is all the the connection of all + + align:start position:0% +axis is all the the connection of all + + + align:start position:0% +axis is all the the connection of all +the dimensions up to D minus + + align:start position:0% +the dimensions up to D minus + + + align:start position:0% +the dimensions up to D minus +2 and and and this AIS SI is the D minus + + align:start position:0% +2 and and and this AIS SI is the D minus + + + align:start position:0% +2 and and and this AIS SI is the D minus +one + + align:start position:0% + + + + align:start position:0% + +okay then the end point the XD minus y = + + align:start position:0% +okay then the end point the XD minus y = + + + align:start position:0% +okay then the end point the XD minus y = +to a at the end + + align:start position:0% +to a at the end + + + align:start position:0% +to a at the end +point so suppose this is the nine of x + + align:start position:0% +point so suppose this is the nine of x + + + align:start position:0% +point so suppose this is the nine of x +equal + + align:start position:0% +equal + + + align:start position:0% +equal +to a + + align:start position:0% + + + + align:start position:0% + +okay so suppose this is the hypersurface + + align:start position:0% +okay so suppose this is the hypersurface + + + align:start position:0% +okay so suppose this is the hypersurface +uh for X XD minus y = to a then that + + align:start position:0% +uh for X XD minus y = to a then that + + + align:start position:0% +uh for X XD minus y = to a then that +boundary recogition tells + + align:start position:0% +boundary recogition tells + + + align:start position:0% +boundary recogition tells +you that whatever open string the + + align:start position:0% +you that whatever open string the + + + align:start position:0% +you that whatever open string the +motion the end point must be restricted + + align:start position:0% +motion the end point must be restricted + + + align:start position:0% +motion the end point must be restricted +to this hypers + + align:start position:0% +to this hypers + + + align:start position:0% +to this hypers +surface okay so that what this + + align:start position:0% +surface okay so that what this + + + align:start position:0% +surface okay so that what this +geometrically what this condition means + + align:start position:0% +geometrically what this condition means + + + align:start position:0% +geometrically what this condition means +it it just say let's consider XT minus 1 + + align:start position:0% +it it just say let's consider XT minus 1 + + + align:start position:0% +it it just say let's consider XT minus 1 += to a which is a hypers Surface in + + align:start position:0% += to a which is a hypers Surface in + + + align:start position:0% += to a which is a hypers Surface in +space time and then then the then this + + align:start position:0% +space time and then then the then this + + + align:start position:0% +space time and then then the then this +then this condition means that the Ender + + align:start position:0% +then this condition means that the Ender + + + align:start position:0% +then this condition means that the Ender +point of the + + align:start position:0% +point of the + + + align:start position:0% +point of the +string must be restricted to this + + align:start position:0% +string must be restricted to this + + + align:start position:0% +string must be restricted to this +surface the interior of the string can + + align:start position:0% +surface the interior of the string can + + + align:start position:0% +surface the interior of the string can +be any can be out have low restriction + + align:start position:0% +be any can be out have low restriction + + + align:start position:0% +be any can be out have low restriction +but end the point have to be on this + + align:start position:0% +but end the point have to be on this + + + align:start position:0% +but end the point have to be on this +surface okay is this + + align:start position:0% + + + + align:start position:0% + +clear okay so you can + + align:start position:0% +clear okay so you can + + + align:start position:0% +clear okay so you can +generalize so this is the first example + + align:start position:0% +generalize so this is the first example + + + align:start position:0% +generalize so this is the first example +you can generalize let's consider X from + + align:start position:0% +you can generalize let's consider X from + + + align:start position:0% +you can generalize let's consider X from +zero to some value + + align:start position:0% +zero to some value + + + align:start position:0% +zero to some value +P of course p is smaller than the total + + align:start position:0% +P of course p is smaller than the total + + + align:start position:0% +P of course p is smaller than the total +number Dimensions which is n for Sigma 0 + + align:start position:0% +number Dimensions which is n for Sigma 0 + + + align:start position:0% +number Dimensions which is n for Sigma 0 +and the + + align:start position:0% +and the + + + align:start position:0% +and the +pi and + + align:start position:0% +pi and + + + align:start position:0% +pi and +then and then the rest say XP + + + align:start position:0% +then and then the rest say XP + + + + align:start position:0% +then and then the rest say XP + +1 XP + + + align:start position:0% + + + + align:start position:0% + +2 to XT minus one this directions + + align:start position:0% +2 to XT minus one this directions + + + align:start position:0% +2 to XT minus one this directions +we impos the the boundary + + align:start position:0% +we impos the the boundary + + + align:start position:0% +we impos the the boundary +conditions uh and and let me call this a + + align:start position:0% +conditions uh and and let me call this a + + + align:start position:0% +conditions uh and and let me call this a +some Vector + + align:start position:0% +some Vector + + + align:start position:0% +some Vector +a some Vector a for both Sigma and sigma + + align:start position:0% +a some Vector a for both Sigma and sigma + + + align:start position:0% +a some Vector a for both Sigma and sigma +equal to zero and Pi okay so a just some + + align:start position:0% +equal to zero and Pi okay so a just some + + + align:start position:0% +equal to zero and Pi okay so a just some +constant Vector of the same Dimension as + + align:start position:0% +constant Vector of the same Dimension as + + + align:start position:0% +constant Vector of the same Dimension as +the number of X here okay the same as + + align:start position:0% +the number of X here okay the same as + + + align:start position:0% +the number of X here okay the same as +the number of X here and and this is + + align:start position:0% +the number of X here and and this is + + + align:start position:0% +the number of X here and and this is +just a more General way to impose this + + align:start position:0% +just a more General way to impose this + + + align:start position:0% +just a more General way to impose this +to more directions okay + + align:start position:0% + + + + align:start position:0% + +is this notation + + align:start position:0% +is this notation + + + align:start position:0% +is this notation +clear yes it's why is there a repeated + + align:start position:0% +clear yes it's why is there a repeated + + + align:start position:0% +clear yes it's why is there a repeated +superscript oh sorry pus P plus + + align:start position:0% + + + + align:start position:0% + +2 yes and maybe do we talk about like a + + align:start position:0% +2 yes and maybe do we talk about like a + + + align:start position:0% +2 yes and maybe do we talk about like a +different zero and Pi behaviors or is + + align:start position:0% +different zero and Pi behaviors or is + + + align:start position:0% +different zero and Pi behaviors or is +that not interesting no we will talk + + align:start position:0% +that not interesting no we will talk + + + align:start position:0% +that not interesting no we will talk +about that let's look at simple cage + + align:start position:0% +about that let's look at simple cage + + + align:start position:0% +about that let's look at simple cage +first yeah + + align:start position:0% + + + + align:start position:0% + +so is this notation + + align:start position:0% +so is this notation + + + align:start position:0% +so is this notation +clear so so again I can do this on the + + align:start position:0% +clear so so again I can do this on the + + + align:start position:0% +clear so so again I can do this on the +similar plot like + + align:start position:0% +similar plot like + + + align:start position:0% +similar plot like +this so now horizontal + + align:start position:0% +this so now horizontal + + + align:start position:0% +this so now horizontal +axis I do x0 to p and vertical axis I do + + align:start position:0% +axis I do x0 to p and vertical axis I do + + + align:start position:0% +axis I do x0 to p and vertical axis I do +p p + 1 all the way to D minus one so + + align:start position:0% +p p + 1 all the way to D minus one so + + + align:start position:0% +p p + 1 all the way to D minus one so +now both axis are multiple + + align:start position:0% +now both axis are multiple + + + align:start position:0% +now both axis are multiple +dimensional and then + + align:start position:0% +dimensional and then + + + align:start position:0% +dimensional and then +this this specifies + + align:start position:0% + + + + align:start position:0% + +so this + + align:start position:0% +so this + + + align:start position:0% +so this +a specifies a + + align:start position:0% +a specifies a + + + align:start position:0% +a specifies a +p plus one + + align:start position:0% + + + + align:start position:0% + +dimensional hypersurface uh + + align:start position:0% + + + + align:start position:0% + +surface right so + + align:start position:0% +surface right so + + + align:start position:0% +surface right so +this so so the value of those coordinate + + align:start position:0% +this so so the value of those coordinate + + + align:start position:0% +this so so the value of those coordinate +are + + align:start position:0% +are + + + align:start position:0% +are +fixed but the value of those coordinate + + align:start position:0% +fixed but the value of those coordinate + + + align:start position:0% +fixed but the value of those coordinate +can be arbitrary + + align:start position:0% +can be arbitrary + + + align:start position:0% +can be arbitrary +so so there's p+ one fre parameter here + + align:start position:0% +so so there's p+ one fre parameter here + + + align:start position:0% +so so there's p+ one fre parameter here +okay and so this is p+1 dimensional + + align:start position:0% +okay and so this is p+1 dimensional + + + align:start position:0% +okay and so this is p+1 dimensional +surface in the space time and this + + align:start position:0% +surface in the space time and this + + + align:start position:0% +surface in the space time and this +condition means that the end point of + + align:start position:0% +condition means that the end point of + + + align:start position:0% +condition means that the end point of +the whatever open string must be + + align:start position:0% +the whatever open string must be + + + align:start position:0% +the whatever open string must be +restricted to this + + align:start position:0% + + + + align:start position:0% + +surface okay + + align:start position:0% + + + + align:start position:0% + +is the picture + + align:start position:0% + + + + align:start position:0% + +clear yes + + align:start position:0% + + + + align:start position:0% + +sorry yeah we are talking about the how + + align:start position:0% +sorry yeah we are talking about the how + + + align:start position:0% +sorry yeah we are talking about the how +to impose the uh uh what's the meaning + + align:start position:0% +to impose the uh uh what's the meaning + + + align:start position:0% +to impose the uh uh what's the meaning +of impose the dally boundary + + align:start position:0% +of impose the dally boundary + + + align:start position:0% +of impose the dally boundary +condition instead of Luman boundary + + align:start position:0% +condition instead of Luman boundary + + + align:start position:0% +condition instead of Luman boundary +condition so we now impose the dur + + align:start position:0% +condition so we now impose the dur + + + align:start position:0% +condition so we now impose the dur +boundary condition which corresponding + + align:start position:0% +boundary condition which corresponding + + + align:start position:0% +boundary condition which corresponding +to the evaluation of the end point + + align:start position:0% +to the evaluation of the end point + + + align:start position:0% +to the evaluation of the end point +should be + + align:start position:0% +should be + + + align:start position:0% +should be +zero and then this can be specified by + + align:start position:0% +zero and then this can be specified by + + + align:start position:0% +zero and then this can be specified by +the end point you take some constant + + align:start position:0% +the end point you take some constant + + + align:start position:0% +the end point you take some constant +value and so that's the + + align:start position:0% +value and so that's the + + + align:start position:0% +value and so that's the +geometric um way to think about this D + + align:start position:0% +geometric um way to think about this D + + + align:start position:0% +geometric um way to think about this D +different der boundary + + align:start position:0% + + + + align:start position:0% + +conditions + + align:start position:0% +conditions + + + align:start position:0% +conditions +okay so if you look at this + + align:start position:0% + + + + align:start position:0% + +naivity so previously when we consider + + align:start position:0% +naivity so previously when we consider + + + align:start position:0% +naivity so previously when we consider +the num boundary condition condition for + + align:start position:0% +the num boundary condition condition for + + + align:start position:0% +the num boundary condition condition for +all + + align:start position:0% +all + + + align:start position:0% +all +directions then then string then there's + + align:start position:0% +directions then then string then there's + + + align:start position:0% +directions then then string then there's +no + + align:start position:0% +no + + + align:start position:0% +no +restriction to the string then the + + align:start position:0% +restriction to the string then the + + + align:start position:0% +restriction to the string then the +string can move anywhere okay so now + + align:start position:0% +string can move anywhere okay so now + + + align:start position:0% +string can move anywhere okay so now +when you when in some directions you + + align:start position:0% +when you when in some directions you + + + align:start position:0% +when you when in some directions you +impose the Der condition then we see + + align:start position:0% +impose the Der condition then we see + + + align:start position:0% +impose the Der condition then we see +that the the motion of the string get + + align:start position:0% +that the the motion of the string get + + + align:start position:0% +that the the motion of the string get +restricted and at this end point now + + align:start position:0% +restricted and at this end point now + + + align:start position:0% +restricted and at this end point now +have to some some sof dimension of the + + align:start position:0% +have to some some sof dimension of the + + + align:start position:0% +have to some some sof dimension of the +space + + align:start position:0% +space + + + align:start position:0% +space +time okay + + align:start position:0% +time okay + + + align:start position:0% +time okay +so at the first side this may seems to + + align:start position:0% +so at the first side this may seems to + + + align:start position:0% +so at the first side this may seems to +be a nonsensical thing to do just you + + align:start position:0% +be a nonsensical thing to do just you + + + align:start position:0% +be a nonsensical thing to do just you +say h you ask why somehow I have to + + align:start position:0% +say h you ask why somehow I have to + + + align:start position:0% +say h you ask why somehow I have to +restrict some open strings to some sub + + align:start position:0% +restrict some open strings to some sub + + + align:start position:0% +restrict some open strings to some sub +manifold in the space time okay so why + + align:start position:0% +manifold in the space time okay so why + + + align:start position:0% +manifold in the space time okay so why +should I do that in particular that + + align:start position:0% +should I do that in particular that + + + align:start position:0% +should I do that in particular that +breaks Len symmetry okay in particular + + align:start position:0% +breaks Len symmetry okay in particular + + + align:start position:0% +breaks Len symmetry okay in particular +that breaks Len so the last thing about + + align:start position:0% +that breaks Len so the last thing about + + + align:start position:0% +that breaks Len so the last thing about +the uh uh uh the new man bation we did + + align:start position:0% +the uh uh uh the new man bation we did + + + align:start position:0% +the uh uh uh the new man bation we did +before in all directions so that respect + + align:start position:0% +before in all directions so that respect + + + align:start position:0% +before in all directions so that respect +Len Symmetry and once you introduce some + + align:start position:0% +Len Symmetry and once you introduce some + + + align:start position:0% +Len Symmetry and once you introduce some +directions the D boundary condition you + + align:start position:0% +directions the D boundary condition you + + + align:start position:0% +directions the D boundary condition you +necessarily break Len symmetry because + + align:start position:0% +necessarily break Len symmetry because + + + align:start position:0% +necessarily break Len symmetry because +you because you select out some SP + + align:start position:0% +you because you select out some SP + + + align:start position:0% +you because you select out some SP +select out some directions versus some + + align:start position:0% +select out some directions versus some + + + align:start position:0% +select out some directions versus some +other okay and uh and so you necessarily + + align:start position:0% +other okay and uh and so you necessarily + + + align:start position:0% +other okay and uh and so you necessarily +break L symmetry you also break + + align:start position:0% +break L symmetry you also break + + + align:start position:0% +break L symmetry you also break +translation + + align:start position:0% +translation + + + align:start position:0% +translation +symmetry because the uh because the yeah + + align:start position:0% +symmetry because the uh because the yeah + + + align:start position:0% +symmetry because the uh because the yeah +you have to specify some sub manifold + + align:start position:0% +you have to specify some sub manifold + + + align:start position:0% +you have to specify some sub manifold +you also break the translations + + align:start position:0% +you also break the translations + + + align:start position:0% +you also break the translations +image so as side this seems to be a + + align:start position:0% +image so as side this seems to be a + + + align:start position:0% +image so as side this seems to be a +nonsensical thing to do so that's why + + align:start position:0% +nonsensical thing to do so that's why + + + align:start position:0% +nonsensical thing to do so that's why +for many years actually people did not + + align:start position:0% +for many years actually people did not + + + align:start position:0% +for many years actually people did not +look at this object even + + align:start position:0% +look at this object even + + + align:start position:0% +look at this object even +though even though for a person to to + + align:start position:0% +though even though for a person to to + + + align:start position:0% +though even though for a person to to +work out screen theory on the first + + align:start position:0% +work out screen theory on the first + + + align:start position:0% +work out screen theory on the first +day you you should already realize the + + align:start position:0% +day you you should already realize the + + + align:start position:0% +day you you should already realize the +boundary conditions okay but for many + + align:start position:0% +boundary conditions okay but for many + + + align:start position:0% +boundary conditions okay but for many +years people did not pay attention to + + align:start position:0% +years people did not pay attention to + + + align:start position:0% +years people did not pay attention to +this kind of bound + + align:start position:0% +this kind of bound + + + align:start position:0% +this kind of bound +Recs but in + + align:start position:0% +Recs but in + + + align:start position:0% +Recs but in +out those that's B recognitions plays a + + align:start position:0% +out those that's B recognitions plays a + + + align:start position:0% +out those that's B recognitions plays a +key role in stren + + align:start position:0% +key role in stren + + + align:start position:0% +key role in stren +theory and the + + align:start position:0% +theory and the + + + align:start position:0% +theory and the +key is to take a slight different + + align:start position:0% +key is to take a slight different + + + align:start position:0% +key is to take a slight different +perspective at those sub manifold + + align:start position:0% +perspective at those sub manifold + + + align:start position:0% +perspective at those sub manifold +okay so now what you should think about + + align:start position:0% +okay so now what you should think about + + + align:start position:0% +okay so now what you should think about +is + + align:start position:0% +is + + + align:start position:0% +is +now what you think about is the + + align:start position:0% +now what you think about is the + + + align:start position:0% +now what you think about is the +following so you think about maybe for + + align:start position:0% +following so you think about maybe for + + + align:start position:0% +following so you think about maybe for +the whole space + + align:start position:0% +the whole space + + + align:start position:0% +the whole space +time for the whole space time time only + + align:start position:0% +time for the whole space time time only + + + align:start position:0% +time for the whole space time time only +close string is the most natural object + + align:start position:0% +close string is the most natural object + + + align:start position:0% +close string is the most natural object +they can move + + align:start position:0% + + + + align:start position:0% + +anywhere but then there are some special + + align:start position:0% +anywhere but then there are some special + + + align:start position:0% +anywhere but then there are some special +places in the in the space + + align:start position:0% +places in the in the space + + + align:start position:0% +places in the in the space +time some kind of + + align:start position:0% +time some kind of + + + align:start position:0% +time some kind of +defect and at those defect the closed + + align:start position:0% +defect and at those defect the closed + + + align:start position:0% +defect and at those defect the closed +string can break to become open + + align:start position:0% +string can break to become open + + + align:start position:0% +string can break to become open +string okay can become open stren and if + + align:start position:0% +string okay can become open stren and if + + + align:start position:0% +string okay can become open stren and if +you take that perspective then that give + + align:start position:0% +you take that perspective then that give + + + align:start position:0% +you take that perspective then that give +special meaning to such kind of special + + align:start position:0% +special meaning to such kind of special + + + align:start position:0% +special meaning to such kind of special +sub manifold which open string can end + + align:start position:0% +sub manifold which open string can end + + + align:start position:0% +sub manifold which open string can end +then then there's some kind of object + + align:start position:0% +then then there's some kind of object + + + align:start position:0% +then then there's some kind of object +there because the existence of certain + + align:start position:0% +there because the existence of certain + + + align:start position:0% +there because the existence of certain +object there then then the open the then + + align:start position:0% +object there then then the open the then + + + align:start position:0% +object there then then the open the then +then the open string can end there okay + + align:start position:0% +then the open string can end there okay + + + align:start position:0% +then the open string can end there okay +yes so indeed if you have that + + align:start position:0% +yes so indeed if you have that + + + align:start position:0% +yes so indeed if you have that +perspective then instead of having it + + align:start position:0% +perspective then instead of having it + + + align:start position:0% +perspective then instead of having it +lie along hyperplanes I mean is it more + + align:start position:0% +lie along hyperplanes I mean is it more + + + align:start position:0% +lie along hyperplanes I mean is it more +natural to have it just lie upon some + + align:start position:0% +natural to have it just lie upon some + + + align:start position:0% +natural to have it just lie upon some +other manifold oh you can yeah I'm just + + align:start position:0% +other manifold oh you can yeah I'm just + + + align:start position:0% +other manifold oh you can yeah I'm just +taking you I'm just sending you the simp + + align:start position:0% +taking you I'm just sending you the simp + + + align:start position:0% +taking you I'm just sending you the simp +example and and once you realize in this + + align:start position:0% +example and and once you realize in this + + + align:start position:0% +example and and once you realize in this +simple example then you can then you can + + align:start position:0% +simple example then you can then you can + + + align:start position:0% +simple example then you can then you can +generalize the OB complicated scenario + + align:start position:0% +generalize the OB complicated scenario + + + align:start position:0% +generalize the OB complicated scenario +you can imagine yeah now let's just + + align:start position:0% +you can imagine yeah now let's just + + + align:start position:0% +you can imagine yeah now let's just +think about in the simplest + + align:start position:0% +think about in the simplest + + + align:start position:0% +think about in the simplest +case imposing those boundary condition + + align:start position:0% +case imposing those boundary condition + + + align:start position:0% +case imposing those boundary condition +become + + align:start position:0% +become + + + align:start position:0% +become +natural if you think + + align:start position:0% +natural if you think + + + align:start position:0% +natural if you think +those those places in space time are + + align:start position:0% +those those places in space time are + + + align:start position:0% +those those places in space time are +special places which which something can + + align:start position:0% +special places which which something can + + + align:start position:0% +special places which which something can +happen is not the same as other places + + align:start position:0% +happen is not the same as other places + + + align:start position:0% +happen is not the same as other places +okay and and to say those spaces are + + align:start position:0% +okay and and to say those spaces are + + + align:start position:0% +okay and and to say those spaces are +happen so you give a + + align:start position:0% +happen so you give a + + + align:start position:0% +happen so you give a +l so so you + + align:start position:0% + + + + align:start position:0% + +imagine so for example you can + + align:start position:0% + + + + align:start position:0% + +imagine + + align:start position:0% + + + + align:start position:0% + +some SpaceTime + + align:start position:0% + + + + align:start position:0% + +defect so + + align:start position:0% + + + + align:start position:0% + +sitting at say this x p + + + align:start position:0% +sitting at say this x p + + + + align:start position:0% +sitting at say this x p + + + align:start position:0% + + + align:start position:0% +x = to + + align:start position:0% +x = to + + + align:start position:0% +x = to +a okay sitting at that + + align:start position:0% +a okay sitting at that + + + align:start position:0% +a okay sitting at that +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +location so where open string can end + + align:start position:0% + + + + align:start position:0% + +so such a defect we call it de + + align:start position:0% + + + + align:start position:0% + +brain we give a + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% + + + + align:start position:0% + +lame + + align:start position:0% +lame + + + align:start position:0% +lame +okay so D is clear because it's a dally + + align:start position:0% +okay so D is clear because it's a dally + + + align:start position:0% +okay so D is clear because it's a dally +binary condition and the Brain because + + align:start position:0% +binary condition and the Brain because + + + align:start position:0% +binary condition and the Brain because +it's some extended surface + + align:start position:0% +it's some extended surface + + + align:start position:0% +it's some extended surface +[Applause] + + align:start position:0% + + + + align:start position:0% + +okay and uh so we often use the rotation + + align:start position:0% +okay and uh so we often use the rotation + + + align:start position:0% +okay and uh so we often use the rotation +say DP + + align:start position:0% + + + + align:start position:0% + +brain so P delot the L of spatial + + align:start position:0% +brain so P delot the L of spatial + + + align:start position:0% +brain so P delot the L of spatial +Dimensions along the brain okay so in + + align:start position:0% +Dimensions along the brain okay so in + + + align:start position:0% +Dimensions along the brain okay so in +this case there's a p spatial Dimensions + + align:start position:0% +this case there's a p spatial Dimensions + + + align:start position:0% +this case there's a p spatial Dimensions +along the plane along the plane along + + align:start position:0% +along the plane along the plane along + + + align:start position:0% +along the plane along the plane along +the uh uh this uh uh um uh brain so we + + align:start position:0% +the uh uh this uh uh um uh brain so we + + + align:start position:0% +the uh uh this uh uh um uh brain so we +call DP brain + + align:start position:0% + + + + align:start position:0% + +okay so right + + align:start position:0% + + + + align:start position:0% + +now right now DP brain is merely just a + + align:start position:0% +now right now DP brain is merely just a + + + align:start position:0% +now right now DP brain is merely just a +place which you impose a boundary + + align:start position:0% +place which you impose a boundary + + + align:start position:0% +place which you impose a boundary +conditions which open string uh uh which + + align:start position:0% +conditions which open string uh uh which + + + align:start position:0% +conditions which open string uh uh which +open strings uh can can end but we will + + align:start position:0% +open strings uh can can end but we will + + + align:start position:0% +open strings uh can can end but we will +soon see that actually a DE is a dynamic + + align:start position:0% +soon see that actually a DE is a dynamic + + + align:start position:0% +soon see that actually a DE is a dynamic +object and it's actually a dynamic + + align:start position:0% +object and it's actually a dynamic + + + align:start position:0% +object and it's actually a dynamic +object and this actually can moves can + + align:start position:0% +object and this actually can moves can + + + align:start position:0% +object and this actually can moves can +can fluctuates can can jump around Etc + + align:start position:0% +can fluctuates can can jump around Etc + + + align:start position:0% +can fluctuates can can jump around Etc +okay and uh so also from this + + align:start position:0% +okay and uh so also from this + + + align:start position:0% +okay and uh so also from this +perspective our previous Newman boundary + + align:start position:0% +perspective our previous Newman boundary + + + align:start position:0% +perspective our previous Newman boundary +condition if we have + + align:start position:0% +condition if we have + + + align:start position:0% +condition if we have +Luman in all + + align:start position:0% +Luman in all + + + align:start position:0% +Luman in all +Direction so if we have Lan boundary + + align:start position:0% +Direction so if we have Lan boundary + + + align:start position:0% +Direction so if we have Lan boundary +condition in all directions + + align:start position:0% +condition in all directions + + + align:start position:0% +condition in all directions +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +then in this + + align:start position:0% +then in this + + + align:start position:0% +then in this +case the open string can end + + align:start position:0% + + + + align:start position:0% + +everywhere and + + align:start position:0% + + + + align:start position:0% + +anywhere from this New + + align:start position:0% + + + + align:start position:0% + +Perspective from this New Perspective we + + align:start position:0% +Perspective from this New Perspective we + + + align:start position:0% +Perspective from this New Perspective we +call this a space fing + + align:start position:0% +call this a space fing + + + align:start position:0% +call this a space fing +brain we call that this + + align:start position:0% +brain we call that this + + + align:start position:0% +brain we call that this +a a space fing + + align:start position:0% +a a space fing + + + align:start position:0% +a a space fing +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +brain + + align:start position:0% + + + + align:start position:0% + +okay so so the Der bound the Lum + + align:start position:0% +okay so so the Der bound the Lum + + + align:start position:0% +okay so so the Der bound the Lum +boundary condition we considered before + + align:start position:0% +boundary condition we considered before + + + align:start position:0% +boundary condition we considered before +uh should be considered as actually you + + align:start position:0% +uh should be considered as actually you + + + align:start position:0% +uh should be considered as actually you +feel the whole space time with such a + + align:start position:0% +feel the whole space time with such a + + + align:start position:0% +feel the whole space time with such a +brain and then uh then uh then the + + align:start position:0% +brain and then uh then uh then the + + + align:start position:0% +brain and then uh then uh then the +string can in principle move anywhere so + + align:start position:0% +string can in principle move anywhere so + + + align:start position:0% +string can in principle move anywhere so +for example in the bosonic string we + + align:start position:0% +for example in the bosonic string we + + + align:start position:0% +for example in the bosonic string we +talked about + + align:start position:0% + + + + align:start position:0% + +before this group corresponding to a d25 + + align:start position:0% +before this group corresponding to a d25 + + + align:start position:0% +before this group corresponding to a d25 +brain + + align:start position:0% + + + + align:start position:0% + +say d25 brain because there's 25 spatial + + align:start position:0% +say d25 brain because there's 25 spatial + + + align:start position:0% +say d25 brain because there's 25 spatial +Dimensions + + align:start position:0% +Dimensions + + + align:start position:0% +Dimensions +okay such a brain when you impose the + + align:start position:0% +okay such a brain when you impose the + + + align:start position:0% +okay such a brain when you impose the +Aluma boundary condition all directions + + align:start position:0% +Aluma boundary condition all directions + + + align:start position:0% +Aluma boundary condition all directions +or if you are in the Super + + align:start position:0% +or if you are in the Super + + + align:start position:0% +or if you are in the Super +string which the total number of space + + align:start position:0% +string which the total number of space + + + align:start position:0% +string which the total number of space +time is 10 and then the spatial number + + align:start position:0% +time is 10 and then the spatial number + + + align:start position:0% +time is 10 and then the spatial number +spatial Dimension is nine then you have + + align:start position:0% +spatial Dimension is nine then you have + + + align:start position:0% +spatial Dimension is nine then you have +dine then these are the dine brains + + align:start position:0% + + + + align:start position:0% + +any questions about + + align:start position:0% + + + + align:start position:0% + +this yes um these B + + align:start position:0% +this yes um these B + + + align:start position:0% +this yes um these B +conditions they're imposed like they're + + align:start position:0% +conditions they're imposed like they're + + + align:start position:0% +conditions they're imposed like they're +imposed at the quantum level right it's + + align:start position:0% +imposed at the quantum level right it's + + + align:start position:0% +imposed at the quantum level right it's +not just that the classical solution um + + align:start position:0% +not just that the classical solution um + + + align:start position:0% +not just that the classical solution um +has to have end points on the Ste but is + + align:start position:0% +has to have end points on the Ste but is + + + align:start position:0% +has to have end points on the Ste but is +the the fluctuations around the + + align:start position:0% +the the fluctuations around the + + + align:start position:0% +the the fluctuations around the +classical solution that we consider yeah + + align:start position:0% +classical solution that we consider yeah + + + align:start position:0% +classical solution that we consider yeah +we will talk about that uh we will talk + + align:start position:0% +we will talk about that uh we will talk + + + align:start position:0% +we will talk about that uh we will talk +about + + align:start position:0% + + + + align:start position:0% + +that + + align:start position:0% + + + + align:start position:0% + +um any other + + align:start position:0% + + + + align:start position:0% + +questions + + align:start position:0% +questions + + + align:start position:0% +questions +good so so let me make a + + align:start position:0% + + + + align:start position:0% + +load you can in principle impress the + + align:start position:0% +load you can in principle impress the + + + align:start position:0% +load you can in principle impress the +Der B condition in any direction you + + align:start position:0% +Der B condition in any direction you + + + align:start position:0% +Der B condition in any direction you +like except in the x0 + + align:start position:0% + + + + align:start position:0% + +direction okay it because x0 cannot be a + + align:start position:0% +direction okay it because x0 cannot be a + + + align:start position:0% +direction okay it because x0 cannot be a +constant x0 have so x0 is the time is + + align:start position:0% +constant x0 have so x0 is the time is + + + align:start position:0% +constant x0 have so x0 is the time is +our real time in the in the minkovsky + + align:start position:0% +our real time in the in the minkovsky + + + align:start position:0% +our real time in the in the minkovsky +space so the scream moves in this + + align:start position:0% +space so the scream moves in this + + + align:start position:0% +space so the scream moves in this +minkovski space time and this x0 is that + + align:start position:0% +minkovski space time and this x0 is that + + + align:start position:0% +minkovski space time and this x0 is that +time and the time cannot stand still + + align:start position:0% +time and the time cannot stand still + + + align:start position:0% +time and the time cannot stand still +okay in order to have this you need the + + align:start position:0% +okay in order to have this you need the + + + align:start position:0% +okay in order to have this you need the +you need that uh uh location to stand + + align:start position:0% +you need that uh uh location to stand + + + align:start position:0% +you need that uh uh location to stand +still and the uh the time cannot stand + + align:start position:0% +still and the uh the time cannot stand + + + align:start position:0% +still and the uh the time cannot stand +still so so so this cannot be a + + align:start position:0% + + + + align:start position:0% + +constant so + + align:start position:0% +constant so + + + align:start position:0% +constant so +um so you cannot imp + + align:start position:0% +um so you cannot imp + + + align:start position:0% +um so you cannot imp +uh the dtive boundary condition in the + + align:start position:0% +uh the dtive boundary condition in the + + + align:start position:0% +uh the dtive boundary condition in the +time + + align:start position:0% +time + + + align:start position:0% +time +Direction so the + + align:start position:0% +Direction so the + + + align:start position:0% +Direction so the +smallest in the minkovski space time the + + align:start position:0% +smallest in the minkovski space time the + + + align:start position:0% +smallest in the minkovski space time the +smallest will be a dzero + + align:start position:0% +smallest will be a dzero + + + align:start position:0% +smallest will be a dzero +brain which impose the D bound condition + + align:start position:0% +brain which impose the D bound condition + + + align:start position:0% +brain which impose the D bound condition +in all spal directions except in time in + + align:start position:0% +in all spal directions except in time in + + + align:start position:0% +in all spal directions except in time in +time you always impose the Lum then then + + align:start position:0% +time you always impose the Lum then then + + + align:start position:0% +time you always impose the Lum then then +the small a small situation would be + + align:start position:0% +the small a small situation would be + + + align:start position:0% +the small a small situation would be +called D zero + + align:start position:0% +called D zero + + + align:start position:0% +called D zero +brain which is a point and then the open + + align:start position:0% +brain which is a point and then the open + + + align:start position:0% +brain which is a point and then the open +string can end on this + + align:start position:0% + + + + align:start position:0% + +point + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +okay yes so a question so this idea + + align:start position:0% +okay yes so a question so this idea + + + align:start position:0% +okay yes so a question so this idea +about calling um the the the noon or + + align:start position:0% +about calling um the the the noon or + + + align:start position:0% +about calling um the the the noon or +boundary conditions uh to like d25 + + align:start position:0% +boundary conditions uh to like d25 + + + align:start position:0% +boundary conditions uh to like d25 +brains or D9 brains so this is a little + + align:start position:0% +brains or D9 brains so this is a little + + + align:start position:0% +brains or D9 brains so this is a little +bit perplexing because it seems like not + + align:start position:0% +bit perplexing because it seems like not + + + align:start position:0% +bit perplexing because it seems like not +imposing d clay boundary conditions this + + align:start position:0% +imposing d clay boundary conditions this + + + align:start position:0% +imposing d clay boundary conditions this +implies that not imposing d clay + + align:start position:0% +implies that not imposing d clay + + + align:start position:0% +implies that not imposing d clay +boundary conditions is equivalent to + + align:start position:0% +boundary conditions is equivalent to + + + align:start position:0% +boundary conditions is equivalent to +applying NOS which is not they're not + + align:start position:0% +applying NOS which is not they're not + + + align:start position:0% +applying NOS which is not they're not +like I mean they're like mutually + + align:start position:0% +like I mean they're like mutually + + + align:start position:0% +like I mean they're like mutually +exclusive it's not like so I mean I + + align:start position:0% +exclusive it's not like so I mean I + + + align:start position:0% +exclusive it's not like so I mean I +don't understand why it is that so so + + align:start position:0% +don't understand why it is that so so + + + align:start position:0% +don't understand why it is that so so +does this thing behave like a 24 brain + + align:start position:0% +does this thing behave like a 24 brain + + + align:start position:0% +does this thing behave like a 24 brain +like does it have the same properties as + + align:start position:0% +like does it have the same properties as + + + align:start position:0% +like does it have the same properties as +like a 24 brain or something like that + + align:start position:0% +like a 24 brain or something like that + + + align:start position:0% +like a 24 brain or something like that +which you mean 25 brain so what I'm + + align:start position:0% +which you mean 25 brain so what I'm + + + align:start position:0% +which you mean 25 brain so what I'm +saying is that it seems that the nomon + + align:start position:0% +saying is that it seems that the nomon + + + align:start position:0% +saying is that it seems that the nomon +boundary conditions have a different + + align:start position:0% +boundary conditions have a different + + + align:start position:0% +boundary conditions have a different +character than like a different flavor + + align:start position:0% +character than like a different flavor + + + align:start position:0% +character than like a different flavor +of how they work than the d clay + + align:start position:0% +of how they work than the d clay + + + align:start position:0% +of how they work than the d clay +boundary conditions so it just seems + + align:start position:0% +boundary conditions so it just seems + + + align:start position:0% +boundary conditions so it just seems +strange to me that you would still call + + align:start position:0% +strange to me that you would still call + + + align:start position:0% +strange to me that you would still call +it a brain like a d25 when um no um so + + align:start position:0% +it a brain like a d25 when um no um so + + + align:start position:0% +it a brain like a d25 when um no um so +so in those + + align:start position:0% +so in those + + + align:start position:0% +so in those +cases in those case for example in this + + align:start position:0% +cases in those case for example in this + + + align:start position:0% +cases in those case for example in this +case which we have L condition all the + + align:start position:0% +case which we have L condition all the + + + align:start position:0% +case which we have L condition all the +other directions except one then this is + + align:start position:0% +other directions except one then this is + + + align:start position:0% +other directions except one then this is +a 24 dimensional then this is a 25 + + align:start position:0% +a 24 dimensional then this is a 25 + + + align:start position:0% +a 24 dimensional then this is a 25 +dimensional manifold which the string uh + + align:start position:0% +dimensional manifold which the string uh + + + align:start position:0% +dimensional manifold which the string uh +okay + + align:start position:0% +okay + + + align:start position:0% +okay +on and uh I just oh I see course so + + align:start position:0% +on and uh I just oh I see course so + + + align:start position:0% +on and uh I just oh I see course so +right you have to apply the all the + + align:start position:0% +right you have to apply the all the + + + align:start position:0% +right you have to apply the all the +other okay I I understand yeah yeah yeah + + align:start position:0% +other okay I I understand yeah yeah yeah + + + align:start position:0% +other okay I I understand yeah yeah yeah +yeah so it's yeah any other + + align:start position:0% + + + + align:start position:0% + +questions okay + + align:start position:0% +questions okay + + + align:start position:0% +questions okay +good so now let's consider more + + align:start position:0% +good so now let's consider more + + + align:start position:0% +good so now let's consider more +complicated slightly more complicated + + align:start position:0% +complicated slightly more complicated + + + align:start position:0% +complicated slightly more complicated +boundary conditions so by introducing + + align:start position:0% +boundary conditions so by introducing + + + align:start position:0% +boundary conditions so by introducing +this deep + + align:start position:0% +this deep + + + align:start position:0% +this deep +brain now you can actually you can have + + align:start position:0% +brain now you can actually you can have + + + align:start position:0% +brain now you can actually you can have +all different possible bound conditions + + align:start position:0% +all different possible bound conditions + + + align:start position:0% +all different possible bound conditions +as we said here there for each Direction + + align:start position:0% +as we said here there for each Direction + + + align:start position:0% +as we said here there for each Direction +you have can have in principle four + + align:start position:0% +you have can have in principle four + + + align:start position:0% +you have can have in principle four +possible choices and then if you have 20 + + align:start position:0% +possible choices and then if you have 20 + + + align:start position:0% +possible choices and then if you have 20 +say so for time Direction you don't but + + align:start position:0% +say so for time Direction you don't but + + + align:start position:0% +say so for time Direction you don't but +for 25 dimensions 25 spatial dimensions + + align:start position:0% +for 25 dimensions 25 spatial dimensions + + + align:start position:0% +for 25 dimensions 25 spatial dimensions +and each Dimension you have a four + + align:start position:0% +and each Dimension you have a four + + + align:start position:0% +and each Dimension you have a four +choices then you have four to the^ 25 + + align:start position:0% +choices then you have four to the^ 25 + + + align:start position:0% +choices then you have four to the^ 25 +possible choices of different boundary + + align:start position:0% +possible choices of different boundary + + + align:start position:0% +possible choices of different boundary +conditions so now let's talk about other + + align:start position:0% +conditions so now let's talk about other + + + align:start position:0% +conditions so now let's talk about other +boundary + + align:start position:0% +boundary + + + align:start position:0% +boundary +conditions + + align:start position:0% +conditions + + + align:start position:0% +conditions +so but but use the picture of deepend we + + align:start position:0% +so but but use the picture of deepend we + + + align:start position:0% +so but but use the picture of deepend we +can talk about them + + align:start position:0% +can talk about them + + + align:start position:0% +can talk about them +all we can talk about them + + align:start position:0% +all we can talk about them + + + align:start position:0% +all we can talk about them +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +all + + align:start position:0% +all + + + align:start position:0% +all +so so let let + + align:start position:0% + + + + align:start position:0% + +consider more than one brains + + align:start position:0% + + + + align:start position:0% + +okay so let's consider the + + align:start position:0% +okay so let's consider the + + + align:start position:0% +okay so let's consider the +situation we have two such DP + + align:start position:0% + + + + align:start position:0% + +brain so the so this direction is still + + align:start position:0% +brain so the so this direction is still + + + align:start position:0% +brain so the so this direction is still +X1 x01 to + + align:start position:0% +X1 x01 to + + + align:start position:0% +X1 x01 to +p and then this is all the transverse + + align:start position:0% +p and then this is all the transverse + + + align:start position:0% +p and then this is all the transverse +all the all the other + + align:start position:0% +all the all the other + + + align:start position:0% +all the all the other +directions so suppose you have a brain + + align:start position:0% +directions so suppose you have a brain + + + align:start position:0% +directions so suppose you have a brain +at the at a + + align:start position:0% +at the at a + + + align:start position:0% +at the at a +and another brain at + + align:start position:0% + + + + align:start position:0% + +B okay at the a vector specified by + + align:start position:0% + + + + align:start position:0% + +B okay so now in this case we can have + + align:start position:0% +B okay so now in this case we can have + + + align:start position:0% +B okay so now in this case we can have +four type of open strings + + align:start position:0% +four type of open strings + + + align:start position:0% +four type of open strings +[Applause] + + align:start position:0% + + + + align:start position:0% + +we can have four type of open strings + + align:start position:0% +we can have four type of open strings + + + align:start position:0% +we can have four type of open strings +for example I can have open string which + + align:start position:0% +for example I can have open string which + + + align:start position:0% +for example I can have open string which +end on + + align:start position:0% +end on + + + align:start position:0% +end on +B and I can have open string end on a + + align:start position:0% +B and I can have open string end on a + + + align:start position:0% +B and I can have open string end on a +but I can also have end open string + + align:start position:0% +but I can also have end open string + + + align:start position:0% +but I can also have end open string +which go from B to a and for o opening + + align:start position:0% +which go from B to a and for o opening + + + align:start position:0% +which go from B to a and for o opening +from A to + + align:start position:0% + + + + align:start position:0% + +B + + align:start position:0% +B + + + align:start position:0% +B +okay so so in this case the boundary + + align:start position:0% +okay so so in this case the boundary + + + align:start position:0% +okay so so in this case the boundary +condition would be the + + align:start position:0% +condition would be the + + + align:start position:0% +condition would be the +x01 to P is still a lum boundary + + align:start position:0% +x01 to P is still a lum boundary + + + align:start position:0% +x01 to P is still a lum boundary +condition for + + align:start position:0% +condition for + + + align:start position:0% +condition for +both for both Sigma equal to Zer and + + align:start position:0% +both for both Sigma equal to Zer and + + + align:start position:0% +both for both Sigma equal to Zer and +sigma equal to + + align:start position:0% + + + + align:start position:0% + +Pi but for + + align:start position:0% + + + + align:start position:0% + +the other + + align:start position:0% + + + + align:start position:0% + +directions okay you can have either your + + align:start position:0% +directions okay you can have either your + + + align:start position:0% +directions okay you can have either your +Sigma zero can either be in a or b + + align:start position:0% + + + + align:start position:0% + +or Sigma equal to Pi can either be a or + + align:start position:0% + + + + align:start position:0% + +b okay so that give you the four type of + + align:start position:0% + + + + align:start position:0% + +strings okay I give you four type of + + align:start position:0% +strings okay I give you four type of + + + align:start position:0% +strings okay I give you four type of +different + + align:start position:0% + + + + align:start position:0% + +strings now you can also consider brains + + align:start position:0% +strings now you can also consider brains + + + align:start position:0% +strings now you can also consider brains +of different + + align:start position:0% +of different + + + align:start position:0% +of different +Dimensions so now you can consider + + align:start position:0% +Dimensions so now you can consider + + + align:start position:0% +Dimensions so now you can consider +brains of a different + + align:start position:0% + + + + align:start position:0% + +dimensions say for + + align:start position:0% +dimensions say for + + + align:start position:0% +dimensions say for +example say suppose let's single out the + + align:start position:0% +example say suppose let's single out the + + + align:start position:0% +example say suppose let's single out the +two directions D- 2 and D- + + align:start position:0% +two directions D- 2 and D- + + + align:start position:0% +two directions D- 2 and D- +1 and let's suppose all the other + + align:start position:0% +1 and let's suppose all the other + + + align:start position:0% +1 and let's suppose all the other +directions are in the Newman + + align:start position:0% +directions are in the Newman + + + align:start position:0% +directions are in the Newman +Direction so let's consider two kind of + + align:start position:0% +Direction so let's consider two kind of + + + align:start position:0% +Direction so let's consider two kind of +brains one is that extended in the D + + align:start position:0% +brains one is that extended in the D + + + align:start position:0% +brains one is that extended in the D +minus 2 Direction say at some value of D + + align:start position:0% +minus 2 Direction say at some value of D + + + align:start position:0% +minus 2 Direction say at some value of D +minus + + align:start position:0% +minus + + + align:start position:0% +minus +one and let's consider another brain + + align:start position:0% +one and let's consider another brain + + + align:start position:0% +one and let's consider another brain +which is localized in both D minus one + + align:start position:0% +which is localized in both D minus one + + + align:start position:0% +which is localized in both D minus one +and D minus + + align:start position:0% +and D minus + + + align:start position:0% +and D minus +2 okay + + align:start position:0% + + + + align:start position:0% + +then you can again have four type of + + align:start position:0% +then you can again have four type of + + + align:start position:0% +then you can again have four type of +strings end + + align:start position:0% +strings end + + + align:start position:0% +strings end +itself ending itself and then ending + + align:start position:0% +itself ending itself and then ending + + + align:start position:0% +itself ending itself and then ending +between these + + align:start position:0% + + + + align:start position:0% + +two so again you can see the oriented + + align:start position:0% +two so again you can see the oriented + + + align:start position:0% +two so again you can see the oriented +stream because we can see the oriented + + align:start position:0% +stream because we can see the oriented + + + align:start position:0% +stream because we can see the oriented +string so you can again can see the + + align:start position:0% +string so you can again can see the + + + align:start position:0% +string so you can again can see the +stream like + + align:start position:0% +stream like + + + align:start position:0% +stream like +that so so so so let me call this brain + + align:start position:0% +that so so so so let me call this brain + + + align:start position:0% +that so so so so let me call this brain +one this brain + + align:start position:0% +one this brain + + + align:start position:0% +one this brain +two so let's consider the one two + + align:start position:0% +two so let's consider the one two + + + align:start position:0% +two so let's consider the one two +string it's from one to two then the one + + align:start position:0% +string it's from one to two then the one + + + align:start position:0% +string it's from one to two then the one +two + + align:start position:0% +two + + + align:start position:0% +two +stren with corresponding to the boundary + + align:start position:0% +stren with corresponding to the boundary + + + align:start position:0% +stren with corresponding to the boundary +condition say at D minus + + align:start position:0% +condition say at D minus + + + align:start position:0% +condition say at D minus +2 say at Sigma equal to + + align:start position:0% + + + + align:start position:0% + +zero you + + align:start position:0% +zero you + + + align:start position:0% +zero you +impose you impose the um the new + + align:start position:0% +impose you impose the um the new + + + align:start position:0% +impose you impose the um the new +boundary + + align:start position:0% +boundary + + + align:start position:0% +boundary +condition okay because it can move + + align:start position:0% +condition okay because it can move + + + align:start position:0% +condition okay because it can move +freely in the in the in the D minus 2 + + align:start position:0% +freely in the in the in the D minus 2 + + + align:start position:0% +freely in the in the in the D minus 2 +Direction and uh but in + + align:start position:0% +Direction and uh but in + + + align:start position:0% +Direction and uh but in +the at Sigma equal to + + align:start position:0% +the at Sigma equal to + + + align:start position:0% +the at Sigma equal to +Pi then then this should be fixed as + + align:start position:0% +Pi then then this should be fixed as + + + align:start position:0% +Pi then then this should be fixed as +some value so let's suppose say this is + + align:start position:0% +some value so let's suppose say this is + + + align:start position:0% +some value so let's suppose say this is +A1 + + align:start position:0% +A1 + + + align:start position:0% +A1 +B1 then then add that we fixed at + + align:start position:0% +B1 then then add that we fixed at + + + align:start position:0% +B1 then then add that we fixed at +A1 Okay so so this is one two string + + align:start position:0% +A1 Okay so so this is one two string + + + align:start position:0% +A1 Okay so so this is one two string +then you can have one end which is a the + + align:start position:0% +then you can have one end which is a the + + + align:start position:0% +then you can have one end which is a the +new Bond new condition but the other end + + align:start position:0% +new Bond new condition but the other end + + + align:start position:0% +new Bond new condition but the other end +which is the bond new + + align:start position:0% + + + + align:start position:0% + +condition okay is this clear to you and + + align:start position:0% +condition okay is this clear to you and + + + align:start position:0% +condition okay is this clear to you and +then for this two one string then we'll + + align:start position:0% +then for this two one string then we'll + + + align:start position:0% +then for this two one string then we'll +be + + align:start position:0% +be + + + align:start position:0% +be +opposite for the two w string for the D + + align:start position:0% +opposite for the two w string for the D + + + align:start position:0% +opposite for the two w string for the D +minus 2 Direction at Sigma equal to Z + + align:start position:0% +minus 2 Direction at Sigma equal to Z + + + align:start position:0% +minus 2 Direction at Sigma equal to Z +will be the D condition but that Sigma + + align:start position:0% +will be the D condition but that Sigma + + + align:start position:0% +will be the D condition but that Sigma +equal to Pi would be the new condition + + align:start position:0% + + + + align:start position:0% + +okay any questions about + + align:start position:0% +okay any questions about + + + align:start position:0% +okay any questions about +this so these are pretty + + align:start position:0% +this so these are pretty + + + align:start position:0% +this so these are pretty +simple you just need to you just need to + + align:start position:0% +simple you just need to you just need to + + + align:start position:0% +simple you just need to you just need to +get used to it and spend a couple + + align:start position:0% +get used to it and spend a couple + + + align:start position:0% +get used to it and spend a couple +minutes draw a couple diagram then you + + align:start position:0% +minutes draw a couple diagram then you + + + align:start position:0% +minutes draw a couple diagram then you +will be an expert you'll be exper this + + align:start position:0% +will be an expert you'll be exper this + + + align:start position:0% +will be an expert you'll be exper this +is pretty + + align:start position:0% + + + + align:start position:0% + +Elementary so important remark + + align:start position:0% + + + + align:start position:0% + +say a DP + + align:start position:0% + + + + align:start position:0% + +brain as we said before it breaks + + align:start position:0% +brain as we said before it breaks + + + align:start position:0% +brain as we said before it breaks +translation + + align:start position:0% + + + + align:start position:0% + +symmetry translational andent + + align:start position:0% + + + + align:start position:0% + +symmetries + + align:start position:0% + + + + align:start position:0% + +okay of the original minkovski space + + align:start position:0% + + + + align:start position:0% + +time to a + + align:start position:0% +time to a + + + align:start position:0% +time to a +subgroup say the subgroup is that you + + align:start position:0% +subgroup say the subgroup is that you + + + align:start position:0% +subgroup say the subgroup is that you +have still have translation Symmetry and + + align:start position:0% +have still have translation Symmetry and + + + align:start position:0% +have still have translation Symmetry and +the lent symmetry along the brain + + align:start position:0% +the lent symmetry along the brain + + + align:start position:0% +the lent symmetry along the brain +Direction say along the brain Direction + + align:start position:0% +Direction say along the brain Direction + + + align:start position:0% +Direction say along the brain Direction +you still can translate the string can + + align:start position:0% +you still can translate the string can + + + align:start position:0% +you still can translate the string can +still translate in that direction and + + align:start position:0% +still translate in that direction and + + + align:start position:0% +still translate in that direction and +still there's no R IM in that direction + + align:start position:0% +still there's no R IM in that direction + + + align:start position:0% +still there's no R IM in that direction +so so there's still F symmetry in one p + + align:start position:0% +so so there's still F symmetry in one p + + + align:start position:0% +so so there's still F symmetry in one p +one comma P so in the time and P spatial + + align:start position:0% +one comma P so in the time and P spatial + + + align:start position:0% +one comma P so in the time and P spatial +Dimensions along the + + align:start position:0% +Dimensions along the + + + align:start position:0% +Dimensions along the +brain and then you you have rotational + + align:start position:0% +brain and then you you have rotational + + + align:start position:0% +brain and then you you have rotational +symmetries in the direction transverse + + align:start position:0% +symmetries in the direction transverse + + + align:start position:0% +symmetries in the direction transverse +to the brain so that's D minus oneus + + align:start position:0% +to the brain so that's D minus oneus + + + align:start position:0% +to the brain so that's D minus oneus +P okay so that's the so that's the + + align:start position:0% +P okay so that's the so that's the + + + align:start position:0% +P okay so that's the so that's the +rotation among those coordinates so you + + align:start position:0% +rotation among those coordinates so you + + + align:start position:0% +rotation among those coordinates so you +can have the lent symmetry along those + + align:start position:0% +can have the lent symmetry along those + + + align:start position:0% +can have the lent symmetry along those +directions then the rotational symmetry + + align:start position:0% +directions then the rotational symmetry + + + align:start position:0% +directions then the rotational symmetry +is along those directions okay so this + + align:start position:0% +is along those directions okay so this + + + align:start position:0% +is along those directions okay so this +is for TP brain so so the um so this is + + align:start position:0% +is for TP brain so so the um so this is + + + align:start position:0% +is for TP brain so so the um so this is +the remaining + + align:start position:0% + + + + align:start position:0% + +symmetry so this is remaining symmetry + + align:start position:0% +symmetry so this is remaining symmetry + + + align:start position:0% +symmetry so this is remaining symmetry +uh uh uh say if you have a DP brain in + + align:start position:0% +uh uh uh say if you have a DP brain in + + + align:start position:0% +uh uh uh say if you have a DP brain in +the in the in the space time of course + + align:start position:0% +the in the in the space time of course + + + align:start position:0% +the in the in the space time of course +if you have multiple DP brain ex then + + align:start position:0% +if you have multiple DP brain ex then + + + align:start position:0% +if you have multiple DP brain ex then +then then it's broken even + + align:start position:0% +then then it's broken even + + + align:start position:0% +then then it's broken even +more yes why do we assume that brains + + align:start position:0% +more yes why do we assume that brains + + + align:start position:0% +more yes why do we assume that brains +are + + align:start position:0% +are + + + align:start position:0% +are +topologically open not compa oh yeah we + + align:start position:0% +topologically open not compa oh yeah we + + + align:start position:0% +topologically open not compa oh yeah we +can talk yeah here I'm just talking + + align:start position:0% +can talk yeah here I'm just talking + + + align:start position:0% +can talk yeah here I'm just talking +about the simplest situation I'm + + align:start position:0% +about the simplest situation I'm + + + align:start position:0% +about the simplest situation I'm +imposing the simplest boundary condition + + align:start position:0% +imposing the simplest boundary condition + + + align:start position:0% +imposing the simplest boundary condition +just like this kind of boundary + + align:start position:0% +just like this kind of boundary + + + align:start position:0% +just like this kind of boundary +conditions and then this kind of + + align:start position:0% +conditions and then this kind of + + + align:start position:0% +conditions and then this kind of +boundary conditions is applies to the + + align:start position:0% +boundary conditions is applies to the + + + align:start position:0% +boundary conditions is applies to the +infinite the um yeah you can once later + + align:start position:0% +infinite the um yeah you can once later + + + align:start position:0% +infinite the um yeah you can once later +we talk about the debr can be dynamical + + align:start position:0% +we talk about the debr can be dynamical + + + align:start position:0% +we talk about the debr can be dynamical +ex then you can consider complicated + + align:start position:0% + + + + align:start position:0% + +configurations + + align:start position:0% +configurations + + + align:start position:0% +configurations +yes so so far we consider one boundary + + align:start position:0% +yes so so far we consider one boundary + + + align:start position:0% +yes so so far we consider one boundary +condition is + + align:start position:0% + + + + align:start position:0% + +zero yeah so how about condition when + + align:start position:0% +zero yeah so how about condition when + + + align:start position:0% +zero yeah so how about condition when +derivative is non + + align:start position:0% +derivative is non + + + align:start position:0% +derivative is non +zero and then so when Sigma X is non Z + + align:start position:0% +zero and then so when Sigma X is non Z + + + align:start position:0% +zero and then so when Sigma X is non Z +some Conant numberers + + align:start position:0% +some Conant numberers + + + align:start position:0% +some Conant numberers +and there was like X + + align:start position:0% +and there was like X + + + align:start position:0% +and there was like X +Plus ah you are saying something like + + align:start position:0% +Plus ah you are saying something like + + + align:start position:0% +Plus ah you are saying something like +this you're saying the some combination + + align:start position:0% +this you're saying the some combination + + + align:start position:0% +this you're saying the some combination +of + + align:start position:0% +of + + + align:start position:0% +of +this X Plus der yeah yeah yeah that can + + align:start position:0% +this X Plus der yeah yeah yeah that can + + + align:start position:0% +this X Plus der yeah yeah yeah that can +happen that does not happen in the + + align:start position:0% +happen that does not happen in the + + + align:start position:0% +happen that does not happen in the +straight minkovski space because in the + + align:start position:0% +straight minkovski space because in the + + + align:start position:0% +straight minkovski space because in the +straight movi space this is the uh the + + align:start position:0% +straight movi space this is the uh the + + + align:start position:0% +straight movi space this is the uh the +action so you can only have one or the + + align:start position:0% +action so you can only have one or the + + + align:start position:0% +action so you can only have one or the +other but if you say have vovi but you + + align:start position:0% +other but if you say have vovi but you + + + align:start position:0% +other but if you say have vovi but you +turn on some Electric + + align:start position:0% +turn on some Electric + + + align:start position:0% +turn on some Electric +fi then then you can actually have such + + align:start position:0% +fi then then you can actually have such + + + align:start position:0% +fi then then you can actually have such +kind of mix bound conditions yeah just + + align:start position:0% +kind of mix bound conditions yeah just + + + align:start position:0% +kind of mix bound conditions yeah just +there there exist such St it depend on + + align:start position:0% +there there exist such St it depend on + + + align:start position:0% +there there exist such St it depend on +the specific dynamical situation so this + + align:start position:0% +the specific dynamical situation so this + + + align:start position:0% +the specific dynamical situation so this +is a this is empty flat Movic space then + + align:start position:0% +is a this is empty flat Movic space then + + + align:start position:0% +is a this is empty flat Movic space then +you can only have those bound + + align:start position:0% +you can only have those bound + + + align:start position:0% +you can only have those bound +recognitions and when some con also can + + align:start position:0% +recognitions and when some con also can + + + align:start position:0% +recognitions and when some con also can +be + + align:start position:0% + + + + align:start position:0% + +to sorry when + + align:start position:0% +to sorry when + + + align:start position:0% +to sorry when +X um that I'm not sure uh uh uh that is + + align:start position:0% +X um that I'm not sure uh uh uh that is + + + align:start position:0% +X um that I'm not sure uh uh uh that is +different uh um yeah because that does + + align:start position:0% +different uh um yeah because that does + + + align:start position:0% +different uh um yeah because that does +not satisfy that the uh does not satisfy + + align:start position:0% +not satisfy that the uh does not satisfy + + + align:start position:0% +not satisfy that the uh does not satisfy +that boundary condition and so so we + + align:start position:0% +that boundary condition and so so we + + + align:start position:0% +that boundary condition and so so we +have to look at specific + + align:start position:0% +have to look at specific + + + align:start position:0% +have to look at specific +situation we have to look at specific + + align:start position:0% +situation we have to look at specific + + + align:start position:0% +situation we have to look at specific +situation just for the flat minkovski + + align:start position:0% +situation just for the flat minkovski + + + align:start position:0% +situation just for the flat minkovski +space these are the only boundary + + align:start position:0% +space these are the only boundary + + + align:start position:0% +space these are the only boundary +condition you can have and uh and the we + + align:start position:0% +condition you can have and uh and the we + + + align:start position:0% +condition you can have and uh and the we +will not have uh we will not be able to + + align:start position:0% +will not have uh we will not be able to + + + align:start position:0% +will not have uh we will not be able to +do it in this course but you can + + align:start position:0% +do it in this course but you can + + + align:start position:0% +do it in this course but you can +consider the situation uh uh because the + + align:start position:0% +consider the situation uh uh because the + + + align:start position:0% +consider the situation uh uh because the +in open string you can have + + align:start position:0% +in open string you can have + + + align:start position:0% +in open string you can have +electromagnetic field you can have a + + align:start position:0% +electromagnetic field you can have a + + + align:start position:0% +electromagnetic field you can have a +photon so you can in principle t on + + align:start position:0% +photon so you can in principle t on + + + align:start position:0% +photon so you can in principle t on +electromagnetic field and then that will + + align:start position:0% +electromagnetic field and then that will + + + align:start position:0% +electromagnetic field and then that will +modify the boundary condition then you + + align:start position:0% +modify the boundary condition then you + + + align:start position:0% +modify the boundary condition then you +can have actually mixed boundary + + align:start position:0% + + + + align:start position:0% + +conditions do people ever consider this + + align:start position:0% +conditions do people ever consider this + + + align:start position:0% +conditions do people ever consider this +string between two de brains as + + align:start position:0% +string between two de brains as + + + align:start position:0% +string between two de brains as +topological defect because it happening + + align:start position:0% +topological defect because it happening + + + align:start position:0% +topological defect because it happening +between you mean stream between + + align:start position:0% +between you mean stream between + + + align:start position:0% +between you mean stream between +different stream before between + + align:start position:0% +different stream before between + + + align:start position:0% +different stream before between +different de brains + + align:start position:0% +different de brains + + + align:start position:0% +different de brains +yes you can see that the de brain + + align:start position:0% +yes you can see that the de brain + + + align:start position:0% +yes you can see that the de brain +themselves as topological defect rather + + align:start position:0% +themselves as topological defect rather + + + align:start position:0% +themselves as topological defect rather +than the the the stream between them as + + align:start position:0% +than the the the stream between them as + + + align:start position:0% +than the the the stream between them as +topological defect the de themselves are + + align:start position:0% +topological defect the de themselves are + + + align:start position:0% +topological defect the de themselves are +defect strings are just yeah as we will + + align:start position:0% +defect strings are just yeah as we will + + + align:start position:0% +defect strings are just yeah as we will +talk about we will talk about it now uh + + align:start position:0% +talk about we will talk about it now uh + + + align:start position:0% +talk about we will talk about it now uh +uh the strings on the de brain they're + + align:start position:0% +uh the strings on the de brain they're + + + align:start position:0% +uh the strings on the de brain they're +just the excitations of the de + + align:start position:0% + + + + align:start position:0% + +brains so now after talking about those + + align:start position:0% +brains so now after talking about those + + + align:start position:0% +brains so now after talking about those +boundary conditions then we can again go + + align:start position:0% +boundary conditions then we can again go + + + align:start position:0% +boundary conditions then we can again go +through the procedure of qu quaning open + + align:start position:0% +through the procedure of qu quaning open + + + align:start position:0% +through the procedure of qu quaning open +string with those boundary conditions + + align:start position:0% +string with those boundary conditions + + + align:start position:0% +string with those boundary conditions +okay then we see what do we + + align:start position:0% + + + + align:start position:0% + +get now let's talk about the open stream + + align:start position:0% +get now let's talk about the open stream + + + align:start position:0% +get now let's talk about the open stream +Spectrum on the DP brain + + align:start position:0% +Spectrum on the DP brain + + + align:start position:0% +Spectrum on the DP brain +so so as you can see already from those + + align:start position:0% + + + + align:start position:0% + +pictures because they restriction on + + align:start position:0% +pictures because they restriction on + + + align:start position:0% +pictures because they restriction on +their end point so essentially the those + + align:start position:0% +their end point so essentially the those + + + align:start position:0% +their end point so essentially the those +strings they can only move along the + + align:start position:0% +strings they can only move along the + + + align:start position:0% +strings they can only move along the +direction of the brain okay they can + + align:start position:0% +direction of the brain okay they can + + + align:start position:0% +direction of the brain okay they can +only move the direction along the brain + + align:start position:0% +only move the direction along the brain + + + align:start position:0% +only move the direction along the brain +so essentially they can be + + align:start position:0% +so essentially they can be + + + align:start position:0% +so essentially they can be +considered as leing on the brain okay so + + align:start position:0% +considered as leing on the brain okay so + + + align:start position:0% +considered as leing on the brain okay so +those open string are leing on those DP + + align:start position:0% +those open string are leing on those DP + + + align:start position:0% +those open string are leing on those DP +brains Okay so so when we quantize those + + align:start position:0% +brains Okay so so when we quantize those + + + align:start position:0% +brains Okay so so when we quantize those +open strings then we then we will get + + align:start position:0% +open strings then we then we will get + + + align:start position:0% +open strings then we then we will get +the excitations of those open string the + + align:start position:0% +the excitations of those open string the + + + align:start position:0% +the excitations of those open string the +state of those open strings then on the + + align:start position:0% +state of those open strings then on the + + + align:start position:0% +state of those open strings then on the +de brains + + align:start position:0% +de brains + + + align:start position:0% +de brains +okay so so let me first introduce some + + align:start position:0% +okay so so let me first introduce some + + + align:start position:0% +okay so so let me first introduce some +rotations previously we have the + + align:start position:0% +rotations previously we have the + + + align:start position:0% +rotations previously we have the +rotation mu refers to all directions so + + align:start position:0% +rotation mu refers to all directions so + + + align:start position:0% +rotation mu refers to all directions so +now I separate into Alpha and a and + + align:start position:0% +now I separate into Alpha and a and + + + align:start position:0% +now I separate into Alpha and a and +Alpha is the Newman boundary Newman + + align:start position:0% +Alpha is the Newman boundary Newman + + + align:start position:0% +Alpha is the Newman boundary Newman +directions from zero to + + align:start position:0% +directions from zero to + + + align:start position:0% +directions from zero to +p and a are the D uh directions from p + + + align:start position:0% +p and a are the D uh directions from p + + + + align:start position:0% +p and a are the D uh directions from p + +1 to D minus + + align:start position:0% +1 to D minus + + + align:start position:0% +1 to D minus +one okay so this D minus oneus P of them + + align:start position:0% +one okay so this D minus oneus P of them + + + align:start position:0% +one okay so this D minus oneus P of them +okay so D minus y minus P of + + align:start position:0% + + + + align:start position:0% + +them so for the new boundary condition + + align:start position:0% +them so for the new boundary condition + + + align:start position:0% +them so for the new boundary condition +is just identical to what we had + + align:start position:0% +is just identical to what we had + + + align:start position:0% +is just identical to what we had +before so let me just write it down to + + align:start position:0% +before so let me just write it down to + + + align:start position:0% +before so let me just write it down to +remind you + + align:start position:0% + + + + align:start position:0% + +okay so these are the say the most + + align:start position:0% +okay so these are the say the most + + + align:start position:0% +okay so these are the say the most +General + + align:start position:0% +General + + + align:start position:0% +General +solution so so so in this case in + + align:start position:0% +solution so so so in this case in + + + align:start position:0% +solution so so so in this case in +particular if you remember you have XL + + align:start position:0% +particular if you remember you have XL + + + align:start position:0% +particular if you remember you have XL +equal to XR so the left moving and Right + + align:start position:0% +equal to XR so the left moving and Right + + + align:start position:0% +equal to XR so the left moving and Right +Moving are the + + align:start position:0% +Moving are the + + + align:start position:0% +Moving are the +same controlled by the same function and + + align:start position:0% +same controlled by the same function and + + + align:start position:0% +same controlled by the same function and +so that's why you get this cosine coine + + align:start position:0% +so that's why you get this cosine coine + + + align:start position:0% +so that's why you get this cosine coine +and when you take the derivative of + + align:start position:0% +and when you take the derivative of + + + align:start position:0% +and when you take the derivative of +Sigma become s then vanishes at the end + + align:start position:0% +Sigma become s then vanishes at the end + + + align:start position:0% +Sigma become s then vanishes at the end +point + + align:start position:0% + + + + align:start position:0% + +okay so so this is story is just exactly + + align:start position:0% +okay so so this is story is just exactly + + + align:start position:0% +okay so so this is story is just exactly +identical as before now let's look at + + align:start position:0% +identical as before now let's look at + + + align:start position:0% +identical as before now let's look at +the Der uh + + align:start position:0% +the Der uh + + + align:start position:0% +the Der uh +conditions so the for the Der conditions + + align:start position:0% +conditions so the for the Der conditions + + + align:start position:0% +conditions so the for the Der conditions +Let's uh + + align:start position:0% +Let's uh + + + align:start position:0% +Let's uh +again write down the most + + align:start position:0% + + + + align:start position:0% + +General possible boundary conditions for + + align:start position:0% +General possible boundary conditions for + + + align:start position:0% +General possible boundary conditions for +uh for the boundary uh yeah first write + + align:start position:0% +uh for the boundary uh yeah first write + + + align:start position:0% +uh for the boundary uh yeah first write +down the most General solution + + align:start position:0% +down the most General solution + + + align:start position:0% +down the most General solution +for for for such a field so you have x + + align:start position:0% +for for for such a field so you have x + + + align:start position:0% +for for for such a field so you have x +a then 2 I pa a + + align:start position:0% +a then 2 I pa a + + + align:start position:0% +a then 2 I pa a +t then you have + + align:start position:0% +t then you have + + + align:start position:0% +t then you have +R tus Sigma + + align:start position:0% + + + + align:start position:0% + +and L A Plus + + align:start position:0% +and L A Plus + + + align:start position:0% +and L A Plus +Sigma + + align:start position:0% +Sigma + + + align:start position:0% +Sigma +okay but now the boundary condition we + + align:start position:0% +okay but now the boundary condition we + + + align:start position:0% +okay but now the boundary condition we +need to + + align:start position:0% + + + + align:start position:0% + +impose is X + + align:start position:0% +impose is X + + + align:start position:0% +impose is X +a and sigma equal to zero and + + align:start position:0% +a and sigma equal to zero and + + + align:start position:0% +a and sigma equal to zero and +Pi Sigma 0o T and the Sigma Pi t + + align:start position:0% +Pi Sigma 0o T and the Sigma Pi t + + + align:start position:0% +Pi Sigma 0o T and the Sigma Pi t +equal + + align:start position:0% +equal + + + align:start position:0% +equal +to ba so so here I call them a but let + + align:start position:0% +to ba so so here I call them a but let + + + align:start position:0% +to ba so so here I call them a but let +me call them B because it's AAL to write + + align:start position:0% +me call them B because it's AAL to write + + + align:start position:0% +me call them B because it's AAL to write +a to the a to the index a so let me just + + align:start position:0% +a to the a to the index a so let me just + + + align:start position:0% +a to the a to the index a so let me just +call them B the vector B + + align:start position:0% +call them B the vector B + + + align:start position:0% +call them B the vector B +okay so now we have to impose this + + align:start position:0% +okay so now we have to impose this + + + align:start position:0% +okay so now we have to impose this +boundary + + align:start position:0% +boundary + + + align:start position:0% +boundary +condition so you can immediately see + + align:start position:0% +condition so you can immediately see + + + align:start position:0% +condition so you can immediately see +that because of this this boundary + + align:start position:0% +that because of this this boundary + + + align:start position:0% +that because of this this boundary +condition XA have to be + + align:start position:0% +condition XA have to be + + + align:start position:0% +condition XA have to be +ba okay x a have to be ba and this PA + + align:start position:0% +ba okay x a have to be ba and this PA + + + align:start position:0% +ba okay x a have to be ba and this PA +have to be + + align:start position:0% +have to be + + + align:start position:0% +have to be +zero PA have to be zero otherwise you + + align:start position:0% +zero PA have to be zero otherwise you + + + align:start position:0% +zero PA have to be zero otherwise you +won't satisfy this because this change + + align:start position:0% +won't satisfy this because this change + + + align:start position:0% +won't satisfy this because this change +with + + align:start position:0% +with + + + align:start position:0% +with +time and then you want the sum of them + + align:start position:0% +time and then you want the sum of them + + + align:start position:0% +time and then you want the sum of them +to be zero at x equal to Z Sigma equal + + align:start position:0% +to be zero at x equal to Z Sigma equal + + + align:start position:0% +to be zero at x equal to Z Sigma equal +to zero so that gives you XL = to minus + + align:start position:0% +to zero so that gives you XL = to minus + + + align:start position:0% +to zero so that gives you XL = to minus +XR so this is from the boundary + + align:start position:0% +XR so this is from the boundary + + + align:start position:0% +XR so this is from the boundary +condition at Sigma equal to + + align:start position:0% +condition at Sigma equal to + + + align:start position:0% +condition at Sigma equal to +zero okay + + align:start position:0% +zero okay + + + align:start position:0% +zero okay +and then the boundary condition Sigma + + align:start position:0% +and then the boundary condition Sigma + + + align:start position:0% +and then the boundary condition Sigma +equal to + + align:start position:0% + + + + align:start position:0% + +Pi you deduce both of them a periodic + + align:start position:0% +Pi you deduce both of them a periodic + + + align:start position:0% +Pi you deduce both of them a periodic +bound recognitions the they periodic + + align:start position:0% +bound recognitions the they periodic + + + align:start position:0% +bound recognitions the they periodic +functions in 2 + + align:start position:0% +functions in 2 + + + align:start position:0% +functions in 2 +pi + + align:start position:0% +pi + + + align:start position:0% +pi +okay the + + align:start position:0% +okay the + + + align:start position:0% +okay the +perod uh you can see it easily so at the + + align:start position:0% +perod uh you can see it easily so at the + + + align:start position:0% +perod uh you can see it easily so at the +to Sigma equal to zero you just have XR + + align:start position:0% +to Sigma equal to zero you just have XR + + + align:start position:0% +to Sigma equal to zero you just have XR +to plus XL t equal to yeah should be + + align:start position:0% +to plus XL t equal to yeah should be + + + align:start position:0% +to plus XL t equal to yeah should be +equal to zero so you should XL equal to + + align:start position:0% +equal to zero so you should XL equal to + + + align:start position:0% +equal to zero so you should XL equal to +minus + + align:start position:0% + + + + align:start position:0% + +XR so so now you can just write down + + align:start position:0% +XR so so now you can just write down + + + align:start position:0% +XR so so now you can just write down +explicitly just still this is a periodic + + align:start position:0% +explicitly just still this is a periodic + + + align:start position:0% +explicitly just still this is a periodic +function in 2 pi so the expansion is + + align:start position:0% +function in 2 pi so the expansion is + + + align:start position:0% +function in 2 pi so the expansion is +essentially the same so the only + + align:start position:0% +essentially the same so the only + + + align:start position:0% +essentially the same so the only +difference for those + + align:start position:0% + + + + align:start position:0% + +directions is that now you have B Alpha + + align:start position:0% +directions is that now you have B Alpha + + + align:start position:0% +directions is that now you have B Alpha +ba now you don't have this term because + + align:start position:0% +ba now you don't have this term because + + + align:start position:0% +ba now you don't have this term because +this term is zero and then + + align:start position:0% +this term is zero and then + + + align:start position:0% +this term is zero and then +not equal to zero alpha n + + align:start position:0% +not equal to zero alpha n + + + align:start position:0% +not equal to zero alpha n +a/ nus n t sign in + + align:start position:0% +a/ nus n t sign in + + + align:start position:0% +a/ nus n t sign in +Sigma okay there's some preactor here I + + align:start position:0% +Sigma okay there's some preactor here I + + + align:start position:0% +Sigma okay there's some preactor here I +forgot to write okay some Alpha Prime ex + + align:start position:0% +forgot to write okay some Alpha Prime ex + + + align:start position:0% +forgot to write okay some Alpha Prime ex +by convention let's not worry about + + align:start position:0% +by convention let's not worry about + + + align:start position:0% +by convention let's not worry about +those + + align:start position:0% + + + + align:start position:0% + +things okay + + align:start position:0% + + + + align:start position:0% + +so now you do + + align:start position:0% + + + + align:start position:0% + +quation so the + + align:start position:0% + + + + align:start position:0% + +quation in new boundary condition of + + align:start position:0% +quation in new boundary condition of + + + align:start position:0% +quation in new boundary condition of +course identical to + + align:start position:0% +course identical to + + + align:start position:0% +course identical to +before oh yeah first let me just explain + + align:start position:0% +before oh yeah first let me just explain + + + align:start position:0% +before oh yeah first let me just explain +the PA equal to zero just make R Mark so + + align:start position:0% +the PA equal to zero just make R Mark so + + + align:start position:0% +the PA equal to zero just make R Mark so +so this is of course expected + + align:start position:0% +so this is of course expected + + + align:start position:0% +so this is of course expected +because if the string is limited to + + align:start position:0% +because if the string is limited to + + + align:start position:0% +because if the string is limited to +moving on this plane then of course it + + align:start position:0% +moving on this plane then of course it + + + align:start position:0% +moving on this plane then of course it +cannot move in the perpendicular + + align:start position:0% +cannot move in the perpendicular + + + align:start position:0% +cannot move in the perpendicular +Direction so cannot have Center of mass + + align:start position:0% +Direction so cannot have Center of mass + + + align:start position:0% +Direction so cannot have Center of mass +momentum in the so cannot have cental + + align:start position:0% +momentum in the so cannot have cental + + + align:start position:0% +momentum in the so cannot have cental +mass momentum in the perpendicular + + align:start position:0% +mass momentum in the perpendicular + + + align:start position:0% +mass momentum in the perpendicular +Direction so so this is indeed what you + + align:start position:0% +Direction so so this is indeed what you + + + align:start position:0% +Direction so so this is indeed what you +intuitively expect okay uh uh the the + + align:start position:0% +intuitively expect okay uh uh the the + + + align:start position:0% +intuitively expect okay uh uh the the +center of mass momentum can only be in + + align:start position:0% +center of mass momentum can only be in + + + align:start position:0% +center of mass momentum can only be in +the One Direction can only be in the in + + align:start position:0% +the One Direction can only be in the in + + + align:start position:0% +the One Direction can only be in the in +the Newman + + align:start position:0% + + + + align:start position:0% + +directions so so the quation of the new + + align:start position:0% +directions so so the quation of the new + + + align:start position:0% +directions so so the quation of the new +is exactly the same as before and + + align:start position:0% +is exactly the same as before and + + + align:start position:0% +is exactly the same as before and +actually conation in which + + align:start position:0% + + + + align:start position:0% + +directions with this set up also the + + align:start position:0% + + + + align:start position:0% + +same also exactly the + + align:start position:0% + + + + align:start position:0% + +same because the only only change is + + align:start position:0% +same because the only only change is + + + align:start position:0% +same because the only only change is +coine Sigma go to S Sigma you can work + + align:start position:0% +coine Sigma go to S Sigma you can work + + + align:start position:0% +coine Sigma go to S Sigma you can work +through that procedure and and you find + + align:start position:0% +through that procedure and and you find + + + align:start position:0% +through that procedure and and you find +that uh nothing really changes so + + align:start position:0% +that uh nothing really changes so + + + align:start position:0% +that uh nothing really changes so +exactly the + + align:start position:0% +exactly the + + + align:start position:0% +exactly the +same as that of + + align:start position:0% + + + + align:start position:0% + +n + + align:start position:0% + + + + align:start position:0% + +okay in + + align:start position:0% +okay in + + + align:start position:0% +okay in +particular in particular the commutation + + align:start position:0% +particular in particular the commutation + + + align:start position:0% +particular in particular the commutation +relations between all those + + align:start position:0% +relations between all those + + + align:start position:0% +relations between all those +modes does not change at all just are + + align:start position:0% +modes does not change at all just are + + + align:start position:0% +modes does not change at all just are +exact the same as what you would have in + + align:start position:0% +exact the same as what you would have in + + + align:start position:0% +exact the same as what you would have in +the in the um + + align:start position:0% +the in the um + + + align:start position:0% +the in the um +um in the uh um in the Luman case so + + align:start position:0% +um in the uh um in the Luman case so + + + align:start position:0% +um in the uh um in the Luman case so +this is also physically + + align:start position:0% +this is also physically + + + align:start position:0% +this is also physically +latal this is a physical + + align:start position:0% +latal this is a physical + + + align:start position:0% +latal this is a physical +Lal so imposing such boundary + + align:start position:0% +Lal so imposing such boundary + + + align:start position:0% +Lal so imposing such boundary +conditions essentially you only restrict + + align:start position:0% +conditions essentially you only restrict + + + align:start position:0% +conditions essentially you only restrict +to the center of mass motion so you can + + align:start position:0% +to the center of mass motion so you can + + + align:start position:0% +to the center of mass motion so you can +no longer move in the perpendicular + + align:start position:0% +no longer move in the perpendicular + + + align:start position:0% +no longer move in the perpendicular +directions but the string can oscillates + + align:start position:0% +directions but the string can oscillates + + + align:start position:0% +directions but the string can oscillates +but string can still oscillate in all 10 + + align:start position:0% +but string can still oscillate in all 10 + + + align:start position:0% +but string can still oscillate in all 10 +Dimensions there's no difference in the + + align:start position:0% +Dimensions there's no difference in the + + + align:start position:0% +Dimensions there's no difference in the +way the string illat and uh so so stram + + align:start position:0% +way the string illat and uh so so stram + + + align:start position:0% +way the string illat and uh so so stram +still oscillates in 10 Dimensions so uh + + align:start position:0% +still oscillates in 10 Dimensions so uh + + + align:start position:0% +still oscillates in 10 Dimensions so uh +so everything is the + + align:start position:0% + + + + align:start position:0% + +same yeah a Str still oscillat in all + + align:start position:0% +same yeah a Str still oscillat in all + + + align:start position:0% +same yeah a Str still oscillat in all +the in all directions in + + align:start position:0% +the in all directions in + + + align:start position:0% +the in all directions in +particular the Z point energy is the + + align:start position:0% + + + + align:start position:0% + +same 0 point energy on the worldsheet is + + align:start position:0% +same 0 point energy on the worldsheet is + + + align:start position:0% +same 0 point energy on the worldsheet is +the same okay + + align:start position:0% + + + + align:start position:0% + +so this means that the mass formula we + + align:start position:0% +so this means that the mass formula we + + + align:start position:0% +so this means that the mass formula we +derived before for the Newman boundary + + align:start position:0% +derived before for the Newman boundary + + + align:start position:0% +derived before for the Newman boundary +condition we exactly applies without any + + align:start position:0% +condition we exactly applies without any + + + align:start position:0% +condition we exactly applies without any +change okay without any + + align:start position:0% +change okay without any + + + align:start position:0% +change okay without any +change in particular the Mass Spectrum + + align:start position:0% +change in particular the Mass Spectrum + + + align:start position:0% +change in particular the Mass Spectrum +will also be EXA essentially the + + align:start position:0% +will also be EXA essentially the + + + align:start position:0% +will also be EXA essentially the +massless or massive Spectrum will be + + align:start position:0% +massless or massive Spectrum will be + + + align:start position:0% +massless or massive Spectrum will be +also be essentially the exact the same + + align:start position:0% +also be essentially the exact the same + + + align:start position:0% +also be essentially the exact the same +as + + align:start position:0% +as + + + align:start position:0% +as +before uh uh uh uh one second + + align:start position:0% + + + + align:start position:0% + +so so let me just mention one + + align:start position:0% + + + + align:start position:0% + +point that this is + + align:start position:0% +point that this is + + + align:start position:0% +point that this is +identical okay that this is + + align:start position:0% +identical okay that this is + + + align:start position:0% +identical okay that this is +identical is actually related to that + + align:start position:0% +identical is actually related to that + + + align:start position:0% +identical is actually related to that +for the for for the derory boundary + + align:start position:0% +for the for for the derory boundary + + + align:start position:0% +for the for for the derory boundary +condition on both sides uh this is still + + align:start position:0% +condition on both sides uh this is still + + + align:start position:0% +condition on both sides uh this is still +a periodic boundary periodic function to + + align:start position:0% +a periodic boundary periodic function to + + + align:start position:0% +a periodic boundary periodic function to +Pi and so uh and so you get this in such + + align:start position:0% +Pi and so uh and so you get this in such + + + align:start position:0% +Pi and so uh and so you get this in such +a case say if say if one end point is is + + align:start position:0% +a case say if say if one end point is is + + + align:start position:0% +a case say if say if one end point is is +the new bounding condition but the other + + align:start position:0% +the new bounding condition but the other + + + align:start position:0% +the new bounding condition but the other +point end point is the rich bounding + + align:start position:0% +point end point is the rich bounding + + + align:start position:0% +point end point is the rich bounding +condition then the story is a little bit + + align:start position:0% +condition then the story is a little bit + + + align:start position:0% +condition then the story is a little bit +more subtle okay and uh then you + + align:start position:0% +more subtle okay and uh then you + + + align:start position:0% +more subtle okay and uh then you +actually get the then the then the um + + align:start position:0% +actually get the then the then the um + + + align:start position:0% +actually get the then the then the um +then the frequency of each modes become + + align:start position:0% +then the frequency of each modes become + + + align:start position:0% +then the frequency of each modes become +half integer rather than integer and + + align:start position:0% +half integer rather than integer and + + + align:start position:0% +half integer rather than integer and +then you will get the different Zer + + align:start position:0% +then you will get the different Zer + + + align:start position:0% +then you will get the different Zer +Point Energy and there the Spectrum will + + align:start position:0% +Point Energy and there the Spectrum will + + + align:start position:0% +Point Energy and there the Spectrum will +change exact okay um uh so I will not do + + align:start position:0% +change exact okay um uh so I will not do + + + align:start position:0% +change exact okay um uh so I will not do +it + + align:start position:0% +it + + + align:start position:0% +it +now maybe put it in your next p set so + + align:start position:0% +now maybe put it in your next p set so + + + align:start position:0% +now maybe put it in your next p set so +that you can do it + + align:start position:0% +that you can do it + + + align:start position:0% +that you can do it +yourself yeah yeah you have a question I + + align:start position:0% +yourself yeah yeah you have a question I + + + align:start position:0% +yourself yeah yeah you have a question I +think you answer the question what + + align:start position:0% +think you answer the question what + + + align:start position:0% +think you answer the question what +happens p + + align:start position:0% + + + + align:start position:0% + +z Oh yeah yeah for the p z yeah indeed + + align:start position:0% +z Oh yeah yeah for the p z yeah indeed + + + align:start position:0% +z Oh yeah yeah for the p z yeah indeed +it's a little bit tricky to do the light + + align:start position:0% +it's a little bit tricky to do the light + + + align:start position:0% +it's a little bit tricky to do the light +con gaug yeah um um yeah for p z It's + + align:start position:0% +con gaug yeah um um yeah for p z It's + + + align:start position:0% +con gaug yeah um um yeah for p z It's +tricky to do that con gaug but you can + + align:start position:0% +tricky to do that con gaug but you can + + + align:start position:0% +tricky to do that con gaug but you can +do using other quantisation procedure + + align:start position:0% +do using other quantisation procedure + + + align:start position:0% +do using other quantisation procedure +then you can do the same same thing yeah + + align:start position:0% +then you can do the same same thing yeah + + + align:start position:0% +then you can do the same same thing yeah +but the conclusion does not change + + align:start position:0% +but the conclusion does not change + + + align:start position:0% +but the conclusion does not change +between different + + align:start position:0% + + + + align:start position:0% + +piece yes maybe I miss this but for for + + align:start position:0% +piece yes maybe I miss this but for for + + + align:start position:0% +piece yes maybe I miss this but for for +the two different brains if you have a + + align:start position:0% +the two different brains if you have a + + + align:start position:0% +the two different brains if you have a +string going from one brain to another + + align:start position:0% +string going from one brain to another + + + align:start position:0% +string going from one brain to another +yeah you said from a point to a brain + + align:start position:0% +yeah you said from a point to a brain + + + align:start position:0% +yeah you said from a point to a brain +the story changes what about like from + + align:start position:0% +the story changes what about like from + + + align:start position:0% +the story changes what about like from +one brain to another is it exactly the + + align:start position:0% +one brain to another is it exactly the + + + align:start position:0% +one brain to another is it exactly the +same as this or is it oh oh yeah yeah + + align:start position:0% +same as this or is it oh oh yeah yeah + + + align:start position:0% +same as this or is it oh oh yeah yeah +that's also a good question um which I + + align:start position:0% +that's also a good question um which I + + + align:start position:0% +that's also a good question um which I +made Might already have something like + + align:start position:0% +made Might already have something like + + + align:start position:0% +made Might already have something like +this in the current P set um and if not + + align:start position:0% +this in the current P set um and if not + + + align:start position:0% +this in the current P set um and if not +I will put in the next p set + + align:start position:0% +I will put in the next p set + + + align:start position:0% +I will put in the next p set +because you asked + + align:start position:0% +because you asked + + + align:start position:0% +because you asked +uh um yeah you see there's a distance + + align:start position:0% +uh um yeah you see there's a distance + + + align:start position:0% +uh um yeah you see there's a distance +between them so now you actually need to + + align:start position:0% +between them so now you actually need to + + + align:start position:0% +between them so now you actually need to +include the sigma + + align:start position:0% +include the sigma + + + align:start position:0% +include the sigma +term now you actually need to include + + align:start position:0% +term now you actually need to include + + + align:start position:0% +term now you actually need to include +the sigma term here and to count this + + align:start position:0% +the sigma term here and to count this + + + align:start position:0% +the sigma term here and to count this +difference because now the zero and the + + align:start position:0% +difference because now the zero and the + + + align:start position:0% +difference because now the zero and the +pi is no longer the same yeah the here I + + align:start position:0% +pi is no longer the same yeah the here I + + + align:start position:0% +pi is no longer the same yeah the here I +don't need to put in the sigma term + + align:start position:0% +don't need to put in the sigma term + + + align:start position:0% +don't need to put in the sigma term +because the zero and the pi are the same + + align:start position:0% +because the zero and the pi are the same + + + align:start position:0% +because the zero and the pi are the same +yeah so the0 Point Energy would change + + align:start position:0% +yeah so the0 Point Energy would change + + + align:start position:0% +yeah so the0 Point Energy would change +yeah they Point Energy will change and + + align:start position:0% +yeah they Point Energy will change and + + + align:start position:0% +yeah they Point Energy will change and +and essentially it's given by the mass + + align:start position:0% +and essentially it's given by the mass + + + align:start position:0% +and essentially it's given by the mass +of the string stretched between them + + align:start position:0% +of the string stretched between them + + + align:start position:0% +of the string stretched between them +yeah yeah so that will be yeah that's a + + align:start position:0% +yeah yeah so that will be yeah that's a + + + align:start position:0% +yeah yeah so that will be yeah that's a +very instructive exercise actually maybe + + align:start position:0% +very instructive exercise actually maybe + + + align:start position:0% +very instructive exercise actually maybe +I already put in the current piece I + + align:start position:0% +I already put in the current piece I + + + align:start position:0% +I already put in the current piece I +don't remember um + + align:start position:0% +don't remember um + + + align:start position:0% +don't remember um +anyway other + + align:start position:0% + + + + align:start position:0% + +questions good so now now let's look at + + align:start position:0% +questions good so now now let's look at + + + align:start position:0% +questions good so now now let's look at +more explicit at the open stren Spectrum + + align:start position:0% + + + + align:start position:0% + +so again it's the same thing you just + + align:start position:0% +so again it's the same thing you just + + + align:start position:0% +so again it's the same thing you just +act Alpha minus + + align:start position:0% +act Alpha minus + + + align:start position:0% +act Alpha minus +N1 + + align:start position:0% +N1 + + + align:start position:0% +N1 +mu1 you can act M1 + + align:start position:0% + + + + align:start position:0% + +times say + + align:start position:0% +times say + + + align:start position:0% +times say +NK mu + + align:start position:0% +NK mu + + + align:start position:0% +NK mu +k n k + + align:start position:0% +k n k + + + align:start position:0% +k n k +MK the only + + align:start position:0% +MK the only + + + align:start position:0% +MK the only +difference is now your vacuum state is + + align:start position:0% +difference is now your vacuum state is + + + align:start position:0% +difference is now your vacuum state is +only can only have momentum in the P + + align:start position:0% +only can only have momentum in the P + + + align:start position:0% +only can only have momentum in the P +Alpha Direction that's essentially the + + align:start position:0% +Alpha Direction that's essentially the + + + align:start position:0% +Alpha Direction that's essentially the +only difference okay + + align:start position:0% + + + + align:start position:0% + +and uh and again the mass square now is + + align:start position:0% +and uh and again the mass square now is + + + align:start position:0% +and uh and again the mass square now is +just minus P Alpha P Alpha okay only + + align:start position:0% +just minus P Alpha P Alpha okay only + + + align:start position:0% +just minus P Alpha P Alpha okay only +along the Alum + + align:start position:0% +along the Alum + + + align:start position:0% +along the Alum +directions so so this is + + align:start position:0% +directions so so this is + + + align:start position:0% +directions so so this is +really then each mod on the string each + + align:start position:0% +really then each mod on the string each + + + align:start position:0% +really then each mod on the string each +oscillation modes of the string now + + align:start position:0% +oscillation modes of the string now + + + align:start position:0% +oscillation modes of the string now +should really corresponding to a + + align:start position:0% + + + + align:start position:0% + +particle or fields in P plus one + + align:start position:0% +particle or fields in P plus one + + + align:start position:0% +particle or fields in P plus one +dimensional + + align:start position:0% + + + + align:start position:0% + +what + + align:start position:0% + + + + align:start position:0% + +volume of the DP + + align:start position:0% + + + + align:start position:0% + +brain okay so we call this is the W + + align:start position:0% +brain okay so we call this is the W + + + align:start position:0% +brain okay so we call this is the W +volume we call the directions all these + + align:start position:0% +volume we call the directions all these + + + align:start position:0% +volume we call the directions all these +directions together is the W volume of + + align:start position:0% +directions together is the W volume of + + + align:start position:0% +directions together is the W volume of +the DP brain so so since that since the + + align:start position:0% +the DP brain so so since that since the + + + align:start position:0% +the DP brain so so since that since the +string can only move along the DP brain + + align:start position:0% +string can only move along the DP brain + + + align:start position:0% +string can only move along the DP brain +so so they can only corresponding to the + + align:start position:0% +so so they can only corresponding to the + + + align:start position:0% +so so they can only corresponding to the +field or particles within the DP brain + + align:start position:0% +field or particles within the DP brain + + + align:start position:0% +field or particles within the DP brain +they cannot move in the opposite + + align:start position:0% +they cannot move in the opposite + + + align:start position:0% +they cannot move in the opposite +direction they cannot move in the in the + + align:start position:0% +direction they cannot move in the in the + + + align:start position:0% +direction they cannot move in the in the +perpendicular + + align:start position:0% + + + + align:start position:0% + +Direction okay so so the really + + align:start position:0% +Direction okay so so the really + + + align:start position:0% +Direction okay so so the really +leaves on the brain + + align:start position:0% + + + + align:start position:0% + +okay and uh in this then then all those + + align:start position:0% +okay and uh in this then then all those + + + align:start position:0% +okay and uh in this then then all those +things may be + + align:start position:0% +things may be + + + align:start position:0% +things may be +considered as the excitations of the + + align:start position:0% +considered as the excitations of the + + + align:start position:0% +considered as the excitations of the +brains okay + + align:start position:0% +brains okay + + + align:start position:0% +brains okay +what can be the string can be regarded + + align:start position:0% +what can be the string can be regarded + + + align:start position:0% +what can be the string can be regarded +as excitation yeah that's right yeah + + align:start position:0% +as excitation yeah that's right yeah + + + align:start position:0% +as excitation yeah that's right yeah +because you can excite certain strings + + align:start position:0% +because you can excite certain strings + + + align:start position:0% +because you can excite certain strings +and not excite strings excit and they're + + align:start position:0% +and not excite strings excit and they're + + + align:start position:0% +and not excite strings excit and they're +all moving along the + + align:start position:0% +all moving along the + + + align:start position:0% +all moving along the +brain + + align:start position:0% + + + + align:start position:0% + +yeah and the important thing is that the + + align:start position:0% + + + + align:start position:0% + +states should fall into + + align:start position:0% + + + + align:start position:0% + +representations now of this symmetry + + align:start position:0% +representations now of this symmetry + + + align:start position:0% +representations now of this symmetry +because that's the only remaining + + align:start position:0% +because that's the only remaining + + + align:start position:0% +because that's the only remaining +symmetry + + align:start position:0% + + + + align:start position:0% + +okay this + + align:start position:0% + + + + align:start position:0% + +point one + + align:start position:0% +point one + + + align:start position:0% +point one +p and the rotation in the transverse + + align:start position:0% +p and the rotation in the transverse + + + align:start position:0% +p and the rotation in the transverse +directions + + align:start position:0% + + + + align:start position:0% + +okay and again just by + + align:start position:0% +okay and again just by + + + align:start position:0% +okay and again just by +this you can show that you actually make + + align:start position:0% +this you can show that you actually make + + + align:start position:0% +this you can show that you actually make +sense only in the 26 Dimension okay + + align:start position:0% +sense only in the 26 Dimension okay + + + align:start position:0% +sense only in the 26 Dimension okay +again makes sense only in the 26 + + align:start position:0% + + + + align:start position:0% + +Dimension so so now let's again look at + + align:start position:0% +Dimension so so now let's again look at + + + align:start position:0% +Dimension so so now let's again look at +the mass States so so as I mentioned + + align:start position:0% +the mass States so so as I mentioned + + + align:start position:0% +the mass States so so as I mentioned +before the mass formula is exactly the + + align:start position:0% +before the mass formula is exactly the + + + align:start position:0% +before the mass formula is exactly the +same as before because the oscillation + + align:start position:0% +same as before because the oscillation + + + align:start position:0% +same as before because the oscillation +mode behaves exactly the same so the + + align:start position:0% +mode behaves exactly the same so the + + + align:start position:0% +mode behaves exactly the same so the +mass formula exactly behaves the same as + + align:start position:0% +mass formula exactly behaves the same as + + + align:start position:0% +mass formula exactly behaves the same as +before so the + + align:start position:0% + + + + align:start position:0% + +massat then is the + + align:start position:0% + + + + align:start position:0% + +following yeah yeah when we see the + + align:start position:0% +following yeah yeah when we see the + + + align:start position:0% +following yeah yeah when we see the +particles in p+ one dimension World + + align:start position:0% +particles in p+ one dimension World + + + align:start position:0% +particles in p+ one dimension World +volume yeah but you know that inary the + + align:start position:0% +volume yeah but you know that inary the + + + align:start position:0% +volume yeah but you know that inary the +particles it's like a very local object + + align:start position:0% +particles it's like a very local object + + + align:start position:0% +particles it's like a very local object +but the open string can you know one end + + align:start position:0% +but the open string can you know one end + + + align:start position:0% +but the open string can you know one end +one one one end of open string located + + align:start position:0% +one one one end of open string located + + + align:start position:0% +one one one end of open string located +one point not the other one located very + + align:start position:0% +one point not the other one located very + + + align:start position:0% +one point not the other one located very +far away but is that picture same as no + + align:start position:0% +far away but is that picture same as no + + + align:start position:0% +far away but is that picture same as no +no + + align:start position:0% +no + + + align:start position:0% +no +it that's a good + + align:start position:0% +it that's a good + + + align:start position:0% +it that's a good +question so + + align:start position:0% +question so + + + align:start position:0% +question so +um when I say particles is I'm talking + + align:start position:0% +um when I say particles is I'm talking + + + align:start position:0% +um when I say particles is I'm talking +about the uh Center of mass motion okay + + align:start position:0% +about the uh Center of mass motion okay + + + align:start position:0% +about the uh Center of mass motion okay +okay uh uh yeah for each oscillation + + align:start position:0% +okay uh uh yeah for each oscillation + + + align:start position:0% +okay uh uh yeah for each oscillation +modes you see that's corresponding to + + align:start position:0% +modes you see that's corresponding to + + + align:start position:0% +modes you see that's corresponding to +yeah for + + align:start position:0% +yeah for + + + align:start position:0% +yeah for +particular for particular oscillation + + align:start position:0% +particular for particular oscillation + + + align:start position:0% +particular for particular oscillation +modes then the other than other than + + align:start position:0% +modes then the other than other than + + + align:start position:0% +modes then the other than other than +those quantum number yeah uh uh yeah let + + align:start position:0% +those quantum number yeah uh uh yeah let + + + align:start position:0% +those quantum number yeah uh uh yeah let +me finish this I will answer that + + align:start position:0% +me finish this I will answer that + + + align:start position:0% +me finish this I will answer that +question yeah yeah I will write this + + align:start position:0% +question yeah yeah I will write this + + + align:start position:0% +question yeah yeah I will write this +down then see explicitly so so let + + align:start position:0% +down then see explicitly so so let + + + align:start position:0% +down then see explicitly so so let +Master States so so + + align:start position:0% +Master States so so + + + align:start position:0% +Master States so so +again using the light com so again we + + align:start position:0% +again using the light com so again we + + + align:start position:0% +again using the light com so again we +use the light com you can separate the + + align:start position:0% +use the light com you can separate the + + + align:start position:0% +use the light com you can separate the +direction to plus + + align:start position:0% +direction to plus + + + align:start position:0% +direction to plus +minus and I in the in the Newman + + align:start position:0% +minus and I in the in the Newman + + + align:start position:0% +minus and I in the in the Newman +Direction and in the D direction again + + align:start position:0% +Direction and in the D direction again + + + align:start position:0% +Direction and in the D direction again +it's just the p+1 to D minus one + + align:start position:0% +it's just the p+1 to D minus one + + + align:start position:0% +it's just the p+1 to D minus one +okay and then the M mode would be the + + align:start position:0% +okay and then the M mode would be the + + + align:start position:0% +okay and then the M mode would be the +same as before you have Alpha minus one + + align:start position:0% +same as before you have Alpha minus one + + + align:start position:0% +same as before you have Alpha minus one +I acting on P + + align:start position:0% +I acting on P + + + align:start position:0% +I acting on P +Alpha and Alpha minus one a AC on P + + align:start position:0% + + + + align:start position:0% + +Alpha and + + align:start position:0% +Alpha and + + + align:start position:0% +Alpha and +plus plus infinite + + align:start position:0% +plus plus infinite + + + align:start position:0% +plus plus infinite +number plus the uh uh yeah plus infinite + + align:start position:0% +number plus the uh uh yeah plus infinite + + + align:start position:0% +number plus the uh uh yeah plus infinite +number of massive modes + + align:start position:0% +number of massive modes + + + align:start position:0% +number of massive modes +okay so let me just initiate this + + align:start position:0% +okay so let me just initiate this + + + align:start position:0% +okay so let me just initiate this +point so this + + align:start position:0% + + + + align:start position:0% + +so the lighton + + align:start position:0% +so the lighton + + + align:start position:0% +so the lighton +S as before the lighton gauge further + + align:start position:0% +S as before the lighton gauge further + + + align:start position:0% +S as before the lighton gauge further +breaks this pite symmetry to only only a + + align:start position:0% +breaks this pite symmetry to only only a + + + align:start position:0% +breaks this pite symmetry to only only a +subg group but you can already see from + + align:start position:0% +subg group but you can already see from + + + align:start position:0% +subg group but you can already see from +here this must corresponding to a vector + + align:start position:0% +here this must corresponding to a vector + + + align:start position:0% +here this must corresponding to a vector +particle okay so uh so this is like a + + align:start position:0% +particle okay so uh so this is like a + + + align:start position:0% +particle okay so uh so this is like a +mess + + align:start position:0% + + + + align:start position:0% + +Vector M this vector + + align:start position:0% + + + + align:start position:0% + +yeah so uh uh so to answer your question + + align:start position:0% +yeah so uh uh so to answer your question + + + align:start position:0% +yeah so uh uh so to answer your question +so example for for typical modes like + + align:start position:0% +so example for for typical modes like + + + align:start position:0% +so example for for typical modes like +this the only quantum number you have is + + align:start position:0% +this the only quantum number you have is + + + align:start position:0% +this the only quantum number you have is +p + + align:start position:0% +p + + + align:start position:0% +p +Alpha and and this Vector + + align:start position:0% +Alpha and and this Vector + + + align:start position:0% +Alpha and and this Vector +indices this Vector index so so so from + + align:start position:0% +indices this Vector index so so so from + + + align:start position:0% +indices this Vector index so so so from +the perspective of the quantum number + + align:start position:0% +the perspective of the quantum number + + + align:start position:0% +the perspective of the quantum number +and this really is just like a vector + + align:start position:0% +and this really is just like a vector + + + align:start position:0% +and this really is just like a vector +particle yeah just like a vector + + align:start position:0% +particle yeah just like a vector + + + align:start position:0% +particle yeah just like a vector +particle um and and then you can + + align:start position:0% +particle um and and then you can + + + align:start position:0% +particle um and and then you can +describe it by by Vector field + + align:start position:0% +describe it by by Vector field + + + align:start position:0% +describe it by by Vector field +Etc it is a very good + + align:start position:0% +Etc it is a very good + + + align:start position:0% +Etc it is a very good +question say + + align:start position:0% +question say + + + align:start position:0% +question say +suppose in the situation which I have a + + align:start position:0% +suppose in the situation which I have a + + + align:start position:0% +suppose in the situation which I have a +string suppose the stren is really very + + align:start position:0% +string suppose the stren is really very + + + align:start position:0% +string suppose the stren is really very +long it's very big then I should be able + + align:start position:0% +long it's very big then I should be able + + + align:start position:0% +long it's very big then I should be able +to see this one dimensional structure + + align:start position:0% +to see this one dimensional structure + + + align:start position:0% +to see this one dimensional structure +indeed uh then that means that even + + align:start position:0% +indeed uh then that means that even + + + align:start position:0% +indeed uh then that means that even +though this correspond this this just + + align:start position:0% +though this correspond this this just + + + align:start position:0% +though this correspond this this just +corresponding to one particular mode of + + align:start position:0% +corresponding to one particular mode of + + + align:start position:0% +corresponding to one particular mode of +the string and and to see the string + + align:start position:0% +the string and and to see the string + + + align:start position:0% +the string and and to see the string +structure you have to be able to see you + + align:start position:0% +structure you have to be able to see you + + + align:start position:0% +structure you have to be able to see you +can excite this into other uh other + + align:start position:0% +can excite this into other uh other + + + align:start position:0% +can excite this into other uh other +different modes + + align:start position:0% + + + + align:start position:0% + +Etc let say if we just stretch the + + align:start position:0% +Etc let say if we just stretch the + + + align:start position:0% +Etc let say if we just stretch the +string yeah I mean yeah yeah stretch the + + align:start position:0% +string yeah I mean yeah yeah stretch the + + + align:start position:0% +string yeah I mean yeah yeah stretch the +string B to excite the string in a + + align:start position:0% +string B to excite the string in a + + + align:start position:0% +string B to excite the string in a +different way it means living this + + align:start position:0% +different way it means living this + + + align:start position:0% +different way it means living this +particular State oh I see yeah yeah just + + align:start position:0% +particular State oh I see yeah yeah just + + + align:start position:0% +particular State oh I see yeah yeah just +I'm talking about the interpretation of + + align:start position:0% +I'm talking about the interpretation of + + + align:start position:0% +I'm talking about the interpretation of +this particular state which is like A + + align:start position:0% +this particular state which is like A + + + align:start position:0% +this particular state which is like A +Spacetime + + align:start position:0% +Spacetime + + + align:start position:0% +Spacetime +particle okay actually this St uh + + align:start position:0% +particle okay actually this St uh + + + align:start position:0% +particle okay actually this St uh +conversity decided the all the + + align:start position:0% +conversity decided the all the + + + align:start position:0% +conversity decided the all the +configuration of the open SP yeah it + + align:start position:0% +configuration of the open SP yeah it + + + align:start position:0% +configuration of the open SP yeah it +determines all the configuration + + align:start position:0% +determines all the configuration + + + align:start position:0% +determines all the configuration +determin all the oscillation mode of the + + align:start position:0% +determin all the oscillation mode of the + + + align:start position:0% +determin all the oscillation mode of the +open string just the other oscillation + + align:start position:0% +open string just the other oscillation + + + align:start position:0% +open string just the other oscillation +modes they all lot excited okay but of + + align:start position:0% +modes they all lot excited okay but of + + + align:start position:0% +modes they all lot excited okay but of +course if if you can observe this one + + align:start position:0% +course if if you can observe this one + + + align:start position:0% +course if if you can observe this one +dimensional object then you can find the + + align:start position:0% +dimensional object then you can find the + + + align:start position:0% +dimensional object then you can find the +ways to excite them and and then you + + align:start position:0% +ways to excite them and and then you + + + align:start position:0% +ways to excite them and and then you +know this is not a particle it's one + + align:start position:0% +know this is not a particle it's one + + + align:start position:0% +know this is not a particle it's one +dimensional object + + align:start position:0% +dimensional object + + + align:start position:0% +dimensional object +ex yeah + + align:start position:0% +ex yeah + + + align:start position:0% +ex yeah +yeah but in order to see this one diens + + align:start position:0% +yeah but in order to see this one diens + + + align:start position:0% +yeah but in order to see this one diens +structure you have to Pro a final + + align:start position:0% +structure you have to Pro a final + + + align:start position:0% +structure you have to Pro a final +structure than just those quantum + + align:start position:0% +structure than just those quantum + + + align:start position:0% +structure than just those quantum +numbers yeah if if those are the only + + align:start position:0% +numbers yeah if if those are the only + + + align:start position:0% +numbers yeah if if those are the only +quantum number you can Pro then it's + + align:start position:0% +quantum number you can Pro then it's + + + align:start position:0% +quantum number you can Pro then it's +like + + align:start position:0% + + + + align:start position:0% + +particle so so this is like M Vector but + + align:start position:0% +particle so so this is like M Vector but + + + align:start position:0% +particle so so this is like M Vector but +now those + + align:start position:0% +now those + + + align:start position:0% +now those +Skies they have index a which is not in + + align:start position:0% +Skies they have index a which is not in + + + align:start position:0% +Skies they have index a which is not in +the pite here so those are now scal + + align:start position:0% +the pite here so those are now scal + + + align:start position:0% +the pite here so those are now scal +field + + align:start position:0% + + + + align:start position:0% + +Fields okay those are Scala fields on + + align:start position:0% +Fields okay those are Scala fields on + + + align:start position:0% +Fields okay those are Scala fields on +the on the on the world volume of the + + align:start position:0% + + + + align:start position:0% + +difference okay so now we + + align:start position:0% + + + + align:start position:0% + +find so previously when we consider the + + align:start position:0% +find so previously when we consider the + + + align:start position:0% +find so previously when we consider the +all human directions we only see a + + align:start position:0% +all human directions we only see a + + + align:start position:0% +all human directions we only see a +vector field they moving all 26 + + align:start position:0% +vector field they moving all 26 + + + align:start position:0% +vector field they moving all 26 +Dimension but + + align:start position:0% +Dimension but + + + align:start position:0% +Dimension but +now so this so This masses modes they + + align:start position:0% +now so this so This masses modes they + + + align:start position:0% +now so this so This masses modes they +give + + align:start position:0% + + + + align:start position:0% + +rise to a vector field the M Vector + + align:start position:0% +rise to a vector field the M Vector + + + align:start position:0% +rise to a vector field the M Vector +field a + + align:start position:0% +field a + + + align:start position:0% +field a +alpha and + + align:start position:0% +alpha and + + + align:start position:0% +alpha and +uh D minus P minus one scal of field + + align:start position:0% + + + + align:start position:0% + +by a + + align:start position:0% + + + + align:start position:0% + +okay so essentially when you introduce + + align:start position:0% +okay so essentially when you introduce + + + align:start position:0% +okay so essentially when you introduce +de brain compare to the space fing brain + + align:start position:0% +de brain compare to the space fing brain + + + align:start position:0% +de brain compare to the space fing brain +case which we considered before in the + + align:start position:0% +case which we considered before in the + + + align:start position:0% +case which we considered before in the +Luman + + align:start position:0% +Luman + + + align:start position:0% +Luman +Direction the some component of those + + align:start position:0% +Direction the some component of those + + + align:start position:0% +Direction the some component of those +gauge + + align:start position:0% +gauge + + + align:start position:0% +gauge +Fields now become the oscillation in the + + align:start position:0% +Fields now become the oscillation in the + + + align:start position:0% +Fields now become the oscillation in the +transverse Direction and now they just + + align:start position:0% +transverse Direction and now they just + + + align:start position:0% +transverse Direction and now they just +essentially become a a scaler Fields + + align:start position:0% +essentially become a a scaler Fields + + + align:start position:0% +essentially become a a scaler Fields +okay is this + + align:start position:0% +okay is this + + + align:start position:0% +okay is this +clear so so now instead you have a a + + align:start position:0% +clear so so now instead you have a a + + + align:start position:0% +clear so so now instead you have a a +smaller Vector field plus some plus a + + align:start position:0% +smaller Vector field plus some plus a + + + align:start position:0% +smaller Vector field plus some plus a +bunch of Scala + + align:start position:0% + + + + align:start position:0% + +Fields as we said before then the low + + align:start position:0% +Fields as we said before then the low + + + align:start position:0% +Fields as we said before then the low +energy effective + + align:start position:0% + + + + align:start position:0% + +action so the low energy effective + + align:start position:0% + + + + align:start position:0% + +action for such Master + + align:start position:0% + + + + align:start position:0% + +modes must be have the + + align:start position:0% +modes must be have the + + + align:start position:0% +modes must be have the +structure say so this is in the p+ one + + align:start position:0% +structure say so this is in the p+ one + + + align:start position:0% +structure say so this is in the p+ one +dimensional World volume of the string + + align:start position:0% +dimensional World volume of the string + + + align:start position:0% +dimensional World volume of the string +say of a Max well + + align:start position:0% + + + + align:start position:0% + +the and uh and just uh as a uh say Mass + + align:start position:0% +the and uh and just uh as a uh say Mass + + + align:start position:0% +the and uh and just uh as a uh say Mass +scaler + + align:start position:0% + + + + align:start position:0% + +field and then of course they + + align:start position:0% +field and then of course they + + + align:start position:0% +field and then of course they +are more complicated contributions just + + align:start position:0% +are more complicated contributions just + + + align:start position:0% +are more complicated contributions just +this is a low energy and L + + align:start position:0% +this is a low energy and L + + + align:start position:0% +this is a low energy and L +energy then then the structure of those + + align:start position:0% +energy then then the structure of those + + + align:start position:0% +energy then then the structure of those +excitations that must be described by + + align:start position:0% +excitations that must be described by + + + align:start position:0% +excitations that must be described by +this kind of low energy factive + + align:start position:0% +this kind of low energy factive + + + align:start position:0% +this kind of low energy factive +Theory okay and this is again just + + align:start position:0% +Theory okay and this is again just + + + align:start position:0% +Theory okay and this is again just +determined by the universality of a m + + align:start position:0% +determined by the universality of a m + + + align:start position:0% +determined by the universality of a m +modes + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +now now there's + + align:start position:0% +now now there's + + + align:start position:0% +now now there's +very so now let me first + + align:start position:0% +very so now let me first + + + align:start position:0% +very so now let me first +note let me emphasize the a + + align:start position:0% +note let me emphasize the a + + + align:start position:0% +note let me emphasize the a +point is said the + + align:start position:0% +point is said the + + + align:start position:0% +point is said the +number of Master mode M Scala + + align:start position:0% + + + + align:start position:0% + +field so we have such a bunch of scalar + + align:start position:0% +field so we have such a bunch of scalar + + + align:start position:0% +field so we have such a bunch of scalar +Fields okay it's exactly the number of + + align:start position:0% +Fields okay it's exactly the number of + + + align:start position:0% +Fields okay it's exactly the number of +transvers + + align:start position:0% + + + + align:start position:0% + +interactions to the deep + + align:start position:0% + + + + align:start position:0% + +brain okay so essentially associated + + align:start position:0% +brain okay so essentially associated + + + align:start position:0% +brain okay so essentially associated +with each transverse Direction you have + + align:start position:0% +with each transverse Direction you have + + + align:start position:0% +with each transverse Direction you have +a scalar excitations you you have a mly + + align:start position:0% +a scalar excitations you you have a mly + + + align:start position:0% +a scalar excitations you you have a mly +scalar + + align:start position:0% +scalar + + + align:start position:0% +scalar +field okay + + align:start position:0% +field okay + + + align:start position:0% +field okay +so emphasize this + + align:start position:0% + + + + align:start position:0% + +point so those scal + + align:start position:0% +point so those scal + + + align:start position:0% +point so those scal +fields some of you may can already have + + align:start position:0% +fields some of you may can already have + + + align:start position:0% +fields some of you may can already have +guessed they have a very simple + + align:start position:0% +guessed they have a very simple + + + align:start position:0% +guessed they have a very simple +physical + + align:start position:0% +physical + + + align:start position:0% +physical +explanation they have very they have a + + align:start position:0% +explanation they have very they have a + + + align:start position:0% +explanation they have very they have a +very simple physical + + align:start position:0% +very simple physical + + + align:start position:0% +very simple physical +interpretation and those Scala field + + align:start position:0% +interpretation and those Scala field + + + align:start position:0% +interpretation and those Scala field +they can be considered as as describing + + align:start position:0% +they can be considered as as describing + + + align:start position:0% +they can be considered as as describing +the motions and the fluctuations of the + + align:start position:0% +the motions and the fluctuations of the + + + align:start position:0% +the motions and the fluctuations of the +de brain in the transverse + + align:start position:0% +de brain in the transverse + + + align:start position:0% +de brain in the transverse +directions + + align:start position:0% + + + + align:start position:0% + +okay so for each transverse Direction + + align:start position:0% +okay so for each transverse Direction + + + align:start position:0% +okay so for each transverse Direction +you have such a massive scalar + + align:start position:0% +you have such a massive scalar + + + align:start position:0% +you have such a massive scalar +field and each of scalar + + align:start position:0% + + + + align:start position:0% + +field for + + align:start position:0% + + + + align:start position:0% + +so more precisely so more explicitly + + align:start position:0% +so more precisely so more explicitly + + + align:start position:0% +so more precisely so more explicitly +just as a as as a cartoon picture + + align:start position:0% +just as a as as a cartoon picture + + + align:start position:0% +just as a as as a cartoon picture +suppose let's consider say the P minus + + align:start position:0% +suppose let's consider say the P minus + + + align:start position:0% +suppose let's consider say the P minus +One + + align:start position:0% +One + + + align:start position:0% +One +Direction p+ One Direction this + + align:start position:0% +Direction p+ One Direction this + + + align:start position:0% +Direction p+ One Direction this +direction uh p+1 + + align:start position:0% +direction uh p+1 + + + align:start position:0% +direction uh p+1 +Direction so suppose you have a dein + + align:start position:0% +Direction so suppose you have a dein + + + align:start position:0% +Direction so suppose you have a dein +sitting here at some value of + + align:start position:0% +sitting here at some value of + + + align:start position:0% +sitting here at some value of +a + + align:start position:0% +a + + + align:start position:0% +a +okay so when we impose the when we + + align:start position:0% +okay so when we impose the when we + + + align:start position:0% +okay so when we impose the when we +impose the D binary + + align:start position:0% + + + + align:start position:0% + +condition yeah so uh uh uh so those are + + align:start position:0% +condition yeah so uh uh uh so those are + + + align:start position:0% +condition yeah so uh uh uh so those are +the X1 01 and P directions + + align:start position:0% +the X1 01 and P directions + + + align:start position:0% +the X1 01 and P directions +okay yeah yeah uh um yeah this is other + + align:start position:0% +okay yeah yeah uh um yeah this is other + + + align:start position:0% +okay yeah yeah uh um yeah this is other +uh uh x0 and the P directions uh you + + align:start position:0% +uh uh x0 and the P directions uh you + + + align:start position:0% +uh uh x0 and the P directions uh you +have a debring sitting here at some + + align:start position:0% +have a debring sitting here at some + + + align:start position:0% +have a debring sitting here at some +value of + + align:start position:0% +value of + + + align:start position:0% +value of +a so when we impulse the Der boundary + + align:start position:0% +a so when we impulse the Der boundary + + + align:start position:0% +a so when we impulse the Der boundary +conditions that boundary condition does + + align:start position:0% +conditions that boundary condition does + + + align:start position:0% +conditions that boundary condition does +not depend on the value of x0 and P so + + align:start position:0% +not depend on the value of x0 and P so + + + align:start position:0% +not depend on the value of x0 and P so +they are same everywhere so that's why I + + align:start position:0% +they are same everywhere so that's why I + + + align:start position:0% +they are same everywhere so that's why I +draw it + + align:start position:0% +draw it + + + align:start position:0% +draw it +flat exact + + align:start position:0% +flat exact + + + align:start position:0% +flat exact +flat but now if you have some + + align:start position:0% +flat but now if you have some + + + align:start position:0% +flat but now if you have some +excitations in the Five p+ One + + align:start position:0% +excitations in the Five p+ One + + + align:start position:0% +excitations in the Five p+ One +Direction so 5 p+ one is a field + + align:start position:0% + + + + align:start position:0% + +in the world volume of the half can have + + align:start position:0% +in the world volume of the half can have + + + align:start position:0% +in the world volume of the half can have +P for + + align:start position:0% +P for + + + align:start position:0% +P for +momentum you can go to coordinate space + + align:start position:0% +momentum you can go to coordinate space + + + align:start position:0% +momentum you can go to coordinate space +then the F then their functions just X1 + + align:start position:0% +then the F then their functions just X1 + + + align:start position:0% +then the F then their functions just X1 +XP okay X + + align:start position:0% +XP okay X + + + align:start position:0% +XP okay X +XP and then then the profile of this + + align:start position:0% +XP and then then the profile of this + + + align:start position:0% +XP and then then the profile of this +F essentially tells + + align:start position:0% + + + + align:start position:0% + +you that the de brain + + align:start position:0% +you that the de brain + + + align:start position:0% +you that the de brain +so if you have a scal of field + + align:start position:0% +so if you have a scal of field + + + align:start position:0% +so if you have a scal of field +excitation like this then the shape of + + align:start position:0% +excitation like this then the shape of + + + align:start position:0% +excitation like this then the shape of +the de brain actually is no longer + + align:start position:0% +the de brain actually is no longer + + + align:start position:0% +the de brain actually is no longer +strictly flat actually have a profile + + align:start position:0% +strictly flat actually have a profile + + + align:start position:0% +strictly flat actually have a profile +given by this scaler field + + align:start position:0% + + + + align:start position:0% + +okay so I will not justify this precise + + align:start position:0% +okay so I will not justify this precise + + + align:start position:0% +okay so I will not justify this precise +uh so this can be justified + + align:start position:0% +uh so this can be justified + + + align:start position:0% +uh so this can be justified +mathematically to really show that this + + align:start position:0% +mathematically to really show that this + + + align:start position:0% +mathematically to really show that this +is the case okay and I will do that uh + + align:start position:0% +is the case okay and I will do that uh + + + align:start position:0% +is the case okay and I will do that uh +here but let me just + + align:start position:0% + + + + align:start position:0% + +mention some support for this + + align:start position:0% + + + + align:start position:0% + +picture so + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% +um + + + align:start position:0% +um +okay so so you f first you can show at + + align:start position:0% +okay so so you f first you can show at + + + align:start position:0% +okay so so you f first you can show at +the worksheet + + align:start position:0% + + + + align:start position:0% + +level having such excitations + + align:start position:0% + + + + align:start position:0% + +okay so so having such excitations so + + align:start position:0% +okay so so having such excitations so + + + align:start position:0% +okay so so having such excitations so +which I just call it fire + + align:start position:0% + + + + align:start position:0% + +excitations so this is a picture in + + align:start position:0% +excitations so this is a picture in + + + align:start position:0% +excitations so this is a picture in +momentum + + align:start position:0% +momentum + + + align:start position:0% +momentum +space have five excitations + + align:start position:0% + + + + align:start position:0% + +modifies the judicially boundary + + align:start position:0% +modifies the judicially boundary + + + align:start position:0% +modifies the judicially boundary +condition Okay so so this you can show + + align:start position:0% + + + + align:start position:0% + +explicitly so this is first point which + + align:start position:0% +explicitly so this is first point which + + + align:start position:0% +explicitly so this is first point which +I we not going to + + align:start position:0% + + + + align:start position:0% + +there and the second + + align:start position:0% +there and the second + + + align:start position:0% +there and the second +point is that you can actually work out + + align:start position:0% +point is that you can actually work out + + + align:start position:0% +point is that you can actually work out +the precise + + align:start position:0% +the precise + + + align:start position:0% +the precise +preactor there is a way Say by doing a + + align:start position:0% +preactor there is a way Say by doing a + + + align:start position:0% +preactor there is a way Say by doing a +string the um calculation uh Say by + + align:start position:0% +string the um calculation uh Say by + + + align:start position:0% +string the um calculation uh Say by +Computing the partition function this + + align:start position:0% +Computing the partition function this + + + align:start position:0% +Computing the partition function this +there's a way you can actually work out + + align:start position:0% +there's a way you can actually work out + + + align:start position:0% +there's a way you can actually work out +the prefactor precise + + align:start position:0% +the prefactor precise + + + align:start position:0% +the prefactor precise +preactor so let me call this the + + align:start position:0% +preactor so let me call this the + + + align:start position:0% +preactor so let me call this the +equation + + align:start position:0% +equation + + + align:start position:0% +equation +star so you can actually work out + + align:start position:0% +star so you can actually work out + + + align:start position:0% +star so you can actually work out +the so that was just by + + align:start position:0% + + + + align:start position:0% + +General this is just by General + + align:start position:0% +General this is just by General + + + align:start position:0% +General this is just by General +principle say say if you have a Mass + + align:start position:0% +principle say say if you have a Mass + + + align:start position:0% +principle say say if you have a Mass +Spectrum then the L must behave like + + align:start position:0% +Spectrum then the L must behave like + + + align:start position:0% +Spectrum then the L must behave like +this and but but this prefa is not fixed + + align:start position:0% +this and but but this prefa is not fixed + + + align:start position:0% +this and but but this prefa is not fixed +okay and but you can + + align:start position:0% +okay and but you can + + + align:start position:0% +okay and but you can +actually with the interpretation F say + + align:start position:0% +actually with the interpretation F say + + + align:start position:0% +actually with the interpretation F say +as the fluctuations of this der boundary + + align:start position:0% +as the fluctuations of this der boundary + + + align:start position:0% +as the fluctuations of this der boundary +condition you can actually fix the + + align:start position:0% +condition you can actually fix the + + + align:start position:0% +condition you can actually fix the +precise the prefactor + + align:start position:0% +precise the prefactor + + + align:start position:0% +precise the prefactor +here so working out the uh working out + + align:start position:0% +here so working out the uh working out + + + align:start position:0% +here so working out the uh working out +the + + align:start position:0% + + + + align:start position:0% + +pre okay + + align:start position:0% +pre okay + + + align:start position:0% +pre okay +you can show that actually this action + + align:start position:0% +you can show that actually this action + + + align:start position:0% +you can show that actually this action +can be written as the + + align:start position:0% +can be written as the + + + align:start position:0% +can be written as the +following + + align:start position:0% + + + + align:start position:0% + +TP again it's integrated only o over the + + align:start position:0% +TP again it's integrated only o over the + + + align:start position:0% +TP again it's integrated only o over the +water volume of the dein p+ + + align:start position:0% + + + + align:start position:0% + +one and you actually first we find + + align:start position:0% +one and you actually first we find + + + align:start position:0% +one and you actually first we find +actually there's a constant + + align:start position:0% +actually there's a constant + + + align:start position:0% +actually there's a constant +term when you work out that action + + align:start position:0% +term when you work out that action + + + align:start position:0% +term when you work out that action +precisely and then you have + + align:start position:0% +precisely and then you have + + + align:start position:0% +precisely and then you have +this F term + + align:start position:0% + + + + align:start position:0% + +and ex and this uh + + align:start position:0% +and ex and this uh + + + align:start position:0% +and ex and this uh +um let me yeah actually I should have + + align:start position:0% +um let me yeah actually I should have + + + align:start position:0% +um let me yeah actually I should have +done it + + align:start position:0% +done it + + + align:start position:0% +done it +there uh uh so there is a summation in a + + align:start position:0% +there uh uh so there is a summation in a + + + align:start position:0% +there uh uh so there is a summation in a +over here + + align:start position:0% +over here + + + align:start position:0% +over here +right so this TP this + + align:start position:0% +right so this TP this + + + align:start position:0% +right so this TP this +preactor is + + align:start position:0% + + + + align:start position:0% + +actually you can work out the pre SI + + align:start position:0% + + + + align:start position:0% + +preactor and this + + align:start position:0% +preactor and this + + + align:start position:0% +preactor and this +preactor is given by the + + align:start position:0% +preactor is given by the + + + align:start position:0% +preactor is given by the +mass over DP + + align:start position:0% + + + + align:start position:0% + +Bri per unit + + align:start position:0% + + + + align:start position:0% + +volume or in other words the brain + + align:start position:0% +volume or in other words the brain + + + align:start position:0% +volume or in other words the brain +tension so I will explain where does + + align:start position:0% +tension so I will explain where does + + + align:start position:0% +tension so I will explain where does +this come from where how do we Define a + + align:start position:0% +this come from where how do we Define a + + + align:start position:0% +this come from where how do we Define a +brain tension uh but for l let me just + + align:start position:0% +brain tension uh but for l let me just + + + align:start position:0% +brain tension uh but for l let me just +introduce this concept of brain + + align:start position:0% +introduce this concept of brain + + + align:start position:0% +introduce this concept of brain +tension so if you look out the prefa you + + align:start position:0% +tension so if you look out the prefa you + + + align:start position:0% +tension so if you look out the prefa you +find the prefa is + + align:start position:0% +find the prefa is + + + align:start position:0% +find the prefa is +precisely the brain uh tension okay + + align:start position:0% +precisely the brain uh tension okay + + + align:start position:0% +precisely the brain uh tension okay +brain tension so now if you look at this + + align:start position:0% +brain tension so now if you look at this + + + align:start position:0% +brain tension so now if you look at this +equation so then this + + align:start position:0% +equation so then this + + + align:start position:0% +equation so then this +one is just like a static + + align:start position:0% +one is just like a static + + + align:start position:0% +one is just like a static +mm okay this one is like a static mumm + + align:start position:0% +mm okay this one is like a static mumm + + + align:start position:0% +mm okay this one is like a static mumm +so so you also find this one in this a + + align:start position:0% +so so you also find this one in this a + + + align:start position:0% +so so you also find this one in this a +ler effective action + + align:start position:0% +ler effective action + + + align:start position:0% +ler effective action +but this one is very important because + + align:start position:0% +but this one is very important because + + + align:start position:0% +but this one is very important because +the so so this one is like static term + + align:start position:0% +the so so this one is like static term + + + align:start position:0% +the so so this one is like static term +and now if you look at this + + align:start position:0% +and now if you look at this + + + align:start position:0% +and now if you look at this +term so now if you + + align:start position:0% + + + + align:start position:0% + +consider the situation which a alpha is + + align:start position:0% +consider the situation which a alpha is + + + align:start position:0% +consider the situation which a alpha is +equal to zero so you don't have any + + align:start position:0% +equal to zero so you don't have any + + + align:start position:0% +equal to zero so you don't have any +excitation of the vector field but F A + + align:start position:0% +excitation of the vector field but F A + + + align:start position:0% +excitation of the vector field but F A +only depend on T only depend on the + + align:start position:0% + + + + align:start position:0% + +time and then this effective action then + + align:start position:0% +time and then this effective action then + + + align:start position:0% +time and then this effective action then +will + + align:start position:0% +will + + + align:start position:0% +will +become TP then the volume of the + + align:start position:0% +become TP then the volume of the + + + align:start position:0% +become TP then the volume of the +P then DT 12 5 do a + + align:start position:0% + + + + align:start position:0% + +S + + align:start position:0% +S + + + align:start position:0% +S +okay and uh so VP is the + + align:start position:0% + + + + align:start position:0% + +volume of DP brain + + align:start position:0% + + + + align:start position:0% + +volume of the DP brain and this tension + + align:start position:0% +volume of the DP brain and this tension + + + align:start position:0% +volume of the DP brain and this tension +times DP brain so this is just the + + align:start position:0% + + + + align:start position:0% + +mass so this is just the mass so uh so + + align:start position:0% +mass so this is just the mass so uh so + + + align:start position:0% +mass so this is just the mass so uh so +you can rewrite this just one + + align:start position:0% +you can rewrite this just one + + + align:start position:0% +you can rewrite this just one +half + + align:start position:0% +half + + + align:start position:0% +half +and D + + align:start position:0% +and D + + + align:start position:0% +and D +brain by dot + + align:start position:0% + + + + align:start position:0% + +Square + + align:start position:0% +Square + + + align:start position:0% +Square +okay and MD brain + + align:start position:0% + + + + align:start position:0% + +TP times the + + align:start position:0% + + + + align:start position:0% + +volume so you see this is + + align:start position:0% +volume so you see this is + + + align:start position:0% +volume so you see this is +precisely like a + + align:start position:0% +precisely like a + + + align:start position:0% +precisely like a +particle like the whole brain + + align:start position:0% +particle like the whole brain + + + align:start position:0% +particle like the whole brain +moving the Lis motion moving of of some + + align:start position:0% +moving the Lis motion moving of of some + + + align:start position:0% +moving the Lis motion moving of of some +some + + align:start position:0% +some + + + align:start position:0% +some +object okay so again this give you the + + align:start position:0% +object okay so again this give you the + + + align:start position:0% +object okay so again this give you the +interpretation that the f + + align:start position:0% +interpretation that the f + + + align:start position:0% +interpretation that the f +can be interpreted uh as + + align:start position:0% +can be interpreted uh as + + + align:start position:0% +can be interpreted uh as +the as the degree Freedom which describe + + align:start position:0% +the as the degree Freedom which describe + + + align:start position:0% +the as the degree Freedom which describe +the motion of the + + align:start position:0% +the motion of the + + + align:start position:0% +the motion of the +brain + + align:start position:0% + + + + align:start position:0% + +okay h + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +um so do you have any questions about + + align:start position:0% +um so do you have any questions about + + + align:start position:0% +um so do you have any questions about +this yes we introduce the Dynamics of + + align:start position:0% +this yes we introduce the Dynamics of + + + align:start position:0% +this yes we introduce the Dynamics of +brain from begin + + align:start position:0% + + + + align:start position:0% + +with fact between term and D term change + + align:start position:0% +with fact between term and D term change + + + align:start position:0% +with fact between term and D term change +sorry if we introduce the Dynamics for + + align:start position:0% +sorry if we introduce the Dynamics for + + + align:start position:0% +sorry if we introduce the Dynamics for +brain from beginning then with the the + + align:start position:0% +brain from beginning then with the the + + + align:start position:0% +brain from beginning then with the the +pre factors of this Max + + align:start position:0% + + + + align:start position:0% + +now now those prefa depend on your + + align:start position:0% +now now those prefa depend on your + + + align:start position:0% +now now those prefa depend on your +normalization and those prefa depend on + + align:start position:0% +normalization and those prefa depend on + + + align:start position:0% +normalization and those prefa depend on +normalization so you can normalize them + + align:start position:0% +normalization so you can normalize them + + + align:start position:0% +normalization so you can normalize them +in some particular + + align:start position:0% +in some particular + + + align:start position:0% +in some particular +way um you can normalize + + align:start position:0% +way um you can normalize + + + align:start position:0% +way um you can normalize +them yeah what here what I'm saying is + + align:start position:0% +them yeah what here what I'm saying is + + + align:start position:0% +them yeah what here what I'm saying is +that there is a specific larization + + align:start position:0% +that there is a specific larization + + + align:start position:0% +that there is a specific larization +which then the F can precisely be + + align:start position:0% +which then the F can precisely be + + + align:start position:0% +which then the F can precisely be +interpreted + + align:start position:0% +interpreted + + + align:start position:0% +interpreted +as the motion of the D + + align:start position:0% +as the motion of the D + + + align:start position:0% +as the motion of the D +brain yeah five always corresponding to + + align:start position:0% +brain yeah five always corresponding to + + + align:start position:0% +brain yeah five always corresponding to +the motion of D but this specific + + align:start position:0% +the motion of D but this specific + + + align:start position:0% +the motion of D but this specific +lonization then five can be really + + align:start position:0% +lonization then five can be really + + + align:start position:0% +lonization then five can be really +interpret as a dynamical version of this + + align:start position:0% +interpret as a dynamical version of this + + + align:start position:0% +interpret as a dynamical version of this +coordinate in the transverse Direction + + align:start position:0% +coordinate in the transverse Direction + + + align:start position:0% +coordinate in the transverse Direction +and with that normalization then you see + + align:start position:0% +and with that normalization then you see + + + align:start position:0% +and with that normalization then you see +that this n effective action is like the + + align:start position:0% +that this n effective action is like the + + + align:start position:0% +that this n effective action is like the +motion of a massive + + align:start position:0% +motion of a massive + + + align:start position:0% +motion of a massive +object okay it's like a the motion of a + + align:start position:0% +object okay it's like a the motion of a + + + align:start position:0% +object okay it's like a the motion of a +massive object and and this give you the + + align:start position:0% +massive object and and this give you the + + + align:start position:0% +massive object and and this give you the +confirmation that F indeed is the should + + align:start position:0% +confirmation that F indeed is the should + + + align:start position:0% +confirmation that F indeed is the should +be considered + + align:start position:0% +be considered + + + align:start position:0% +be considered +Freedom describe the motion of the deep + + align:start position:0% +Freedom describe the motion of the deep + + + align:start position:0% +Freedom describe the motion of the deep +brain + + align:start position:0% +brain + + + align:start position:0% +brain +yes that's I that is only in the low + + align:start position:0% +yes that's I that is only in the low + + + align:start position:0% +yes that's I that is only in the low +energy continue when you the + + align:start position:0% +energy continue when you the + + + align:start position:0% +energy continue when you the +higher of open Str yeah so yeah so + + align:start position:0% +higher of open Str yeah so yeah so + + + align:start position:0% +higher of open Str yeah so yeah so +that's a good question which I don't + + align:start position:0% +that's a good question which I don't + + + align:start position:0% +that's a good question which I don't +have time to to discuss now uh but I can + + align:start position:0% +have time to to discuss now uh but I can + + + align:start position:0% +have time to to discuss now uh but I can +but I will describe as the beginning of + + align:start position:0% +but I will describe as the beginning of + + + align:start position:0% +but I will describe as the beginning of +next lecture just so so this is a know + + align:start position:0% +next lecture just so so this is a know + + + align:start position:0% +next lecture just so so this is a know +enery story then you can actually + + align:start position:0% +enery story then you can actually + + + align:start position:0% +enery story then you can actually +include the subset of higher order terms + + align:start position:0% +include the subset of higher order terms + + + align:start position:0% +include the subset of higher order terms +then you find those this infinite number + + align:start position:0% +then you find those this infinite number + + + align:start position:0% +then you find those this infinite number +of higher order terms you can sum and + + align:start position:0% +of higher order terms you can sum and + + + align:start position:0% +of higher order terms you can sum and +then this precisely generalize to the + + align:start position:0% +then this precisely generalize to the + + + align:start position:0% +then this precisely generalize to the +motion of a relativistic object yeah + + align:start position:0% +motion of a relativistic object yeah + + + align:start position:0% +motion of a relativistic object yeah +because if you want to yeah because this + + align:start position:0% +because if you want to yeah because this + + + align:start position:0% +because if you want to yeah because this +is no energies have to be non + + align:start position:0% +is no energies have to be non + + + align:start position:0% +is no energies have to be non +relativistic but then you can generalize + + align:start position:0% +relativistic but then you can generalize + + + align:start position:0% +relativistic but then you can generalize +generally if you sum + + align:start position:0% +generally if you sum + + + align:start position:0% +generally if you sum +over infinite number of higher terms + + align:start position:0% +over infinite number of higher terms + + + align:start position:0% +over infinite number of higher terms +then this describe relativistic motion + + align:start position:0% +then this describe relativistic motion + + + align:start position:0% +then this describe relativistic motion +uh of object and again that's a lot of + + align:start position:0% +uh of object and again that's a lot of + + + align:start position:0% +uh of object and again that's a lot of +independent confirmation that this is + + align:start position:0% +independent confirmation that this is + + + align:start position:0% +independent confirmation that this is +the describe the motion of the deep + + align:start position:0% +the describe the motion of the deep + + + align:start position:0% +the describe the motion of the deep +brain yeah yes um so I'm kind of + + align:start position:0% +brain yeah yes um so I'm kind of + + + align:start position:0% +brain yeah yes um so I'm kind of +fundamentally uh confused about how so + + align:start position:0% +fundamentally uh confused about how so + + + align:start position:0% +fundamentally uh confused about how so +we started with a de brain which was a + + align:start position:0% +we started with a de brain which was a + + + align:start position:0% +we started with a de brain which was a +topological defect in our background + + align:start position:0% +topological defect in our background + + + align:start position:0% +topological defect in our background +manifold yeah so like a black brain or + + align:start position:0% +manifold yeah so like a black brain or + + + align:start position:0% +manifold yeah so like a black brain or +something right yeah and uh we are + + align:start position:0% +something right yeah and uh we are + + + align:start position:0% +something right yeah and uh we are +looking at motion of strings in this + + align:start position:0% +looking at motion of strings in this + + + align:start position:0% +looking at motion of strings in this +background manifold yeah and this is so + + align:start position:0% +background manifold yeah and this is so + + + align:start position:0% +background manifold yeah and this is so +why do we all of a sudden have the + + align:start position:0% +why do we all of a sudden have the + + + align:start position:0% +why do we all of a sudden have the +string motion affect the background like + + align:start position:0% +string motion affect the background like + + + align:start position:0% +string motion affect the background like +we never even introduce any couple into + + align:start position:0% +we never even introduce any couple into + + + align:start position:0% +we never even introduce any couple into +the back yeah yeah yeah so that's the + + align:start position:0% +the back yeah yeah yeah so that's the + + + align:start position:0% +the back yeah yeah yeah so that's the +that's + + align:start position:0% +that's + + + align:start position:0% +that's +precisely so this is a very good + + align:start position:0% +precisely so this is a very good + + + align:start position:0% +precisely so this is a very good +question this is + + align:start position:0% +question this is + + + align:start position:0% +question this is +precisely the remarkable thing about the + + align:start position:0% +precisely the remarkable thing about the + + + align:start position:0% +precisely the remarkable thing about the +stren + + align:start position:0% +stren + + + align:start position:0% +stren +the + + align:start position:0% +the + + + align:start position:0% +the +so yeah so uh I was going to say at the + + align:start position:0% +so yeah so uh I was going to say at the + + + align:start position:0% +so yeah so uh I was going to say at the +beginning of Le next but now let me say + + align:start position:0% +beginning of Le next but now let me say + + + align:start position:0% +beginning of Le next but now let me say +it so at the beginning you introduce the + + align:start position:0% +it so at the beginning you introduce the + + + align:start position:0% +it so at the beginning you introduce the +deep brain just by some rigid boundary + + align:start position:0% +deep brain just by some rigid boundary + + + align:start position:0% +deep brain just by some rigid boundary +conditions some rigid boundary + + align:start position:0% +conditions some rigid boundary + + + align:start position:0% +conditions some rigid boundary +conditions + + align:start position:0% +conditions + + + align:start position:0% +conditions +and uh looks like this is a non damic + + align:start position:0% +and uh looks like this is a non damic + + + align:start position:0% +and uh looks like this is a non damic +object because we are introducing some + + align:start position:0% +object because we are introducing some + + + align:start position:0% +object because we are introducing some +rigid boundary + + align:start position:0% +rigid boundary + + + align:start position:0% +rigid boundary +conditions but now when you quantize the + + align:start position:0% +conditions but now when you quantize the + + + align:start position:0% +conditions but now when you quantize the +strings on those deep + + align:start position:0% +strings on those deep + + + align:start position:0% +strings on those deep +brains and then you find the those + + align:start position:0% +brains and then you find the those + + + align:start position:0% +brains and then you find the those +strings now give the give the Deep + + align:start position:0% +strings now give the give the Deep + + + align:start position:0% +strings now give the give the Deep +braing itself + + align:start position:0% + + + + align:start position:0% + +knife is it because there's a graviton + + align:start position:0% +knife is it because there's a graviton + + + align:start position:0% +knife is it because there's a graviton +no no no have nothing to do with + + align:start position:0% +no no no have nothing to do with + + + align:start position:0% +no no no have nothing to do with +graviton have nothing to do with + + align:start position:0% +graviton have nothing to do with + + + align:start position:0% +graviton have nothing to do with +graviton start with a rigid boundary + + align:start position:0% +graviton start with a rigid boundary + + + align:start position:0% +graviton start with a rigid boundary +conditions but now you find a b this + + align:start position:0% +conditions but now you find a b this + + + align:start position:0% +conditions but now you find a b this +boundary conditions then you can + + align:start position:0% +boundary conditions then you can + + + align:start position:0% +boundary conditions then you can +generate then you have some excitations + + align:start position:0% +generate then you have some excitations + + + align:start position:0% +generate then you have some excitations +then the coherent motion of this + + align:start position:0% +then the coherent motion of this + + + align:start position:0% +then the coherent motion of this +excitations now give this + + align:start position:0% +excitations now give this + + + align:start position:0% +excitations now give this +object a + + align:start position:0% +object a + + + align:start position:0% +object a +Dynamics so that's a precis remarkable + + align:start position:0% +Dynamics so that's a precis remarkable + + + align:start position:0% +Dynamics so that's a precis remarkable +thing about String Theory so what if you + + align:start position:0% +thing about String Theory so what if you + + + align:start position:0% +thing about String Theory so what if you +have two strings or both ending on the + + align:start position:0% +have two strings or both ending on the + + + align:start position:0% +have two strings or both ending on the +same brain no no no this including all + + align:start position:0% +same brain no no no this including all + + + align:start position:0% +same brain no no no this including all +the strings you can have as many strings + + align:start position:0% +the strings you can have as many strings + + + align:start position:0% +the strings you can have as many strings +as you want + + align:start position:0% +as you want + + + align:start position:0% +as you want +well we're quantizing one particular + + align:start position:0% +well we're quantizing one particular + + + align:start position:0% +well we're quantizing one particular +object and we're looking at a spectrum + + align:start position:0% +object and we're looking at a spectrum + + + align:start position:0% +object and we're looking at a spectrum +of a single string starting here yeah + + align:start position:0% +of a single string starting here yeah + + + align:start position:0% +of a single string starting here yeah +yeah each string have such excitations + + align:start position:0% +yeah each string have such excitations + + + align:start position:0% +yeah each string have such excitations +but then each different string will + + align:start position:0% +but then each different string will + + + align:start position:0% +but then each different string will +generate a different Dynamics for the no + + align:start position:0% +generate a different Dynamics for the no + + + align:start position:0% +generate a different Dynamics for the no +the same Dynamic you just have two + + align:start position:0% +the same Dynamic you just have two + + + align:start position:0% +the same Dynamic you just have two +particles it's just like you have one + + align:start position:0% +particles it's just like you have one + + + align:start position:0% +particles it's just like you have one +Photon here another Photon there it's + + align:start position:0% +Photon here another Photon there it's + + + align:start position:0% +Photon here another Photon there it's +the same + + align:start position:0% + + + + align:start position:0% + +thing and this is the same + + align:start position:0% +thing and this is the same + + + align:start position:0% +thing and this is the same +thing about how stry regenerate + + align:start position:0% +thing about how stry regenerate + + + align:start position:0% +thing about how stry regenerate +gravity so let me just uh uh say a few + + align:start position:0% +gravity so let me just uh uh say a few + + + align:start position:0% +gravity so let me just uh uh say a few +words here + + align:start position:0% +words here + + + align:start position:0% +words here +so at the beginning when we quanti the + + align:start position:0% +so at the beginning when we quanti the + + + align:start position:0% +so at the beginning when we quanti the +close stream we consider a Clos stream + + align:start position:0% +close stream we consider a Clos stream + + + align:start position:0% +close stream we consider a Clos stream +moving in again in a rigid wi kovski + + align:start position:0% +moving in again in a rigid wi kovski + + + align:start position:0% +moving in again in a rigid wi kovski +space time yeah because that matric is + + align:start position:0% +space time yeah because that matric is + + + align:start position:0% +space time yeah because that matric is +rigid we just consider in the rigid wovi + + align:start position:0% +rigid we just consider in the rigid wovi + + + align:start position:0% +rigid we just consider in the rigid wovi +space time but now when you quantize + + align:start position:0% +space time but now when you quantize + + + align:start position:0% +space time but now when you quantize +that close string then you see that + + align:start position:0% +that close string then you see that + + + align:start position:0% +that close string then you see that +close string actually have been two + + align:start position:0% +close string actually have been two + + + align:start position:0% +close string actually have been two +excitations have spin two + + align:start position:0% +excitations have spin two + + + align:start position:0% +excitations have spin two +excitations that means that string + + align:start position:0% +excitations that means that string + + + align:start position:0% +excitations that means that string +actually has gravity ational effect and + + align:start position:0% +actually has gravity ational effect and + + + align:start position:0% +actually has gravity ational effect and +once you have spin two + + align:start position:0% +once you have spin two + + + align:start position:0% +once you have spin two +excitations then + + align:start position:0% +excitations then + + + align:start position:0% +excitations then +Einstein already from Einstein gravity + + align:start position:0% +Einstein already from Einstein gravity + + + align:start position:0% +Einstein already from Einstein gravity +tells us that the space time is no + + align:start position:0% +tells us that the space time is no + + + align:start position:0% +tells us that the space time is no +longer + + align:start position:0% +longer + + + align:start position:0% +longer +rigid that actually can deform the I + + align:start position:0% +rigid that actually can deform the I + + + align:start position:0% +rigid that actually can deform the I +deform the mop space time by by putting + + align:start position:0% +deform the mop space time by by putting + + + align:start position:0% +deform the mop space time by by putting +in those excitation this been two + + align:start position:0% +in those excitation this been two + + + align:start position:0% +in those excitation this been two +excitations and if you put enough of + + align:start position:0% +excitations and if you put enough of + + + align:start position:0% +excitations and if you put enough of +them then you deform the mov SP time to + + align:start position:0% +them then you deform the mov SP time to + + + align:start position:0% +them then you deform the mov SP time to +some other curve space time then you can + + align:start position:0% +some other curve space time then you can + + + align:start position:0% +some other curve space time then you can +actually describe + + align:start position:0% +actually describe + + + align:start position:0% +actually describe +generically the quantum gravitational + + align:start position:0% +generically the quantum gravitational + + + align:start position:0% +generically the quantum gravitational +dynamics of General curve space time so + + align:start position:0% +dynamics of General curve space time so + + + align:start position:0% +dynamics of General curve space time so +here is the same thing we start with a + + align:start position:0% +here is the same thing we start with a + + + align:start position:0% +here is the same thing we start with a +rid deep brain then we quantize the + + align:start position:0% +rid deep brain then we quantize the + + + align:start position:0% +rid deep brain then we quantize the +excitations on then we quantize the + + align:start position:0% +excitations on then we quantize the + + + align:start position:0% +excitations on then we quantize the +degre freedom on the D brain and then we + + align:start position:0% +degre freedom on the D brain and then we + + + align:start position:0% +degre freedom on the D brain and then we +find those degrees Freedom corresponding + + align:start position:0% +find those degrees Freedom corresponding + + + align:start position:0% +find those degrees Freedom corresponding +to the fluctuation of the D brain and if + + align:start position:0% +to the fluctuation of the D brain and if + + + align:start position:0% +to the fluctuation of the D brain and if +you have enough of them say if you have + + align:start position:0% +you have enough of them say if you have + + + align:start position:0% +you have enough of them say if you have +so have five only depend on T to be the + + align:start position:0% +so have five only depend on T to be the + + + align:start position:0% +so have five only depend on T to be the +same everywhere so that's some coherent + + align:start position:0% +same everywhere so that's some coherent + + + align:start position:0% +same everywhere so that's some coherent +motion for every point on this brain so + + align:start position:0% +motion for every point on this brain so + + + align:start position:0% +motion for every point on this brain so +then say if you build enough kind + + align:start position:0% +then say if you build enough kind + + + align:start position:0% +then say if you build enough kind +excitations then you can actually make + + align:start position:0% +excitations then you can actually make + + + align:start position:0% +excitations then you can actually make +the deep brain moves ET they become a + + align:start position:0% +the deep brain moves ET they become a + + + align:start position:0% +the deep brain moves ET they become a +fully Dynamic object yeah so that's + + align:start position:0% +fully Dynamic object yeah so that's + + + align:start position:0% +fully Dynamic object yeah so that's +precisely the remarkable thing about + + align:start position:0% + + + + align:start position:0% + +yes + + align:start position:0% +yes + + + align:start position:0% +yes +Dynamic just + + align:start position:0% +Dynamic just + + + align:start position:0% +Dynamic just +normalize or no we don't know how to + + align:start position:0% +normalize or no we don't know how to + + + align:start position:0% +normalize or no we don't know how to +describe dynamical brain from the + + align:start position:0% +describe dynamical brain from the + + + align:start position:0% +describe dynamical brain from the +beginning + + align:start position:0% +beginning + + + align:start position:0% +beginning +no that's how we do it we we first start + + align:start position:0% +no that's how we do it we we first start + + + align:start position:0% +no that's how we do it we we first start +with some uh uh so this is called the + + align:start position:0% +with some uh uh so this is called the + + + align:start position:0% +with some uh uh so this is called the +background dependent uh quantization you + + align:start position:0% +background dependent uh quantization you + + + align:start position:0% +background dependent uh quantization you +start with a specific + + align:start position:0% +start with a specific + + + align:start position:0% +start with a specific +solution you start with a specific + + align:start position:0% +solution you start with a specific + + + align:start position:0% +solution you start with a specific +configuration of the de brain which we + + align:start position:0% +configuration of the de brain which we + + + align:start position:0% +configuration of the de brain which we +you happen to be able to quantize then + + align:start position:0% +you happen to be able to quantize then + + + align:start position:0% +you happen to be able to quantize then +you can find all the excitations around + + align:start position:0% +you can find all the excitations around + + + align:start position:0% +you can find all the excitations around +that particular configuration and then + + align:start position:0% +that particular configuration and then + + + align:start position:0% +that particular configuration and then +you can turn on those excitation to move + + align:start position:0% +you can turn on those excitation to move + + + align:start position:0% +you can turn on those excitation to move +away from those + + align:start position:0% +away from those + + + align:start position:0% +away from those +points + + align:start position:0% +points + + + align:start position:0% +points +yeah yeah so that's essentially what + + align:start position:0% +yeah yeah so that's essentially what + + + align:start position:0% +yeah yeah so that's essentially what +we're doing here here right okay okay + + align:start position:0% +we're doing here here right okay okay + + + align:start position:0% +we're doing here here right okay okay +let's stop \ No newline at end of file diff --git a/iR6FUYCNi5A.txt b/iR6FUYCNi5A.txt new file mode 100644 index 0000000000000000000000000000000000000000..5b3c69b31dcf28922292b9df178ab98cdc9854f8 --- /dev/null +++ b/iR6FUYCNi5A.txt @@ -0,0 +1,6203 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +to view additional materials from + + align:start position:0% +to view additional materials from + + + align:start position:0% +to view additional materials from +hundreds of MIT courses visit MIT + + align:start position:0% +hundreds of MIT courses visit MIT + + + align:start position:0% +hundreds of MIT courses visit MIT +opencourseware at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu this is going to be really + + align:start position:0% +ocw.mit.edu this is going to be really + + + align:start position:0% +ocw.mit.edu this is going to be really +informal and you can try and follow + + align:start position:0% +informal and you can try and follow + + + align:start position:0% +informal and you can try and follow +along if you want um I'm just going to + + align:start position:0% +along if you want um I'm just going to + + + align:start position:0% +along if you want um I'm just going to +show you my basic workflow from + + align:start position:0% +show you my basic workflow from + + + align:start position:0% +show you my basic workflow from +illustrator to after effect to Premiere + + align:start position:0% +illustrator to after effect to Premiere + + + align:start position:0% +illustrator to after effect to Premiere +and like some important I guess like + + align:start position:0% +and like some important I guess like + + + align:start position:0% +and like some important I guess like +basic tools that you might + + align:start position:0% + + + + align:start position:0% + +use Elizabeth okay I just started we + + align:start position:0% +use Elizabeth okay I just started we + + + align:start position:0% +use Elizabeth okay I just started we +finally got everything set + + align:start position:0% +finally got everything set + + + align:start position:0% +finally got everything set +up I don't know how + + align:start position:0% + + + + align:start position:0% + +to a little make it any better okay I'll + + align:start position:0% +to a little make it any better okay I'll + + + align:start position:0% +to a little make it any better okay I'll +wait a little bit + + align:start position:0% +wait a little bit + + + align:start position:0% +wait a little bit +okay + + align:start position:0% +okay + + + align:start position:0% +okay +um okay um so first thing is creating + + align:start position:0% +um okay um so first thing is creating + + + align:start position:0% +um okay um so first thing is creating +your canvas so if you open up + + align:start position:0% +your canvas so if you open up + + + align:start position:0% +your canvas so if you open up +illustrator it's just file + + align:start position:0% +illustrator it's just file + + + align:start position:0% +illustrator it's just file +new um you can name it whatever you + + align:start position:0% +new um you can name it whatever you + + + align:start position:0% +new um you can name it whatever you +want and then the profile is going to be + + align:start position:0% +want and then the profile is going to be + + + align:start position:0% +want and then the profile is going to be +automatically set to one of these + + align:start position:0% +automatically set to one of these + + + align:start position:0% +automatically set to one of these +options but I adjust the width and the + + align:start position:0% +options but I adjust the width and the + + + align:start position:0% +options but I adjust the width and the +height to match the screen size of the + + align:start position:0% +height to match the screen size of the + + + align:start position:0% +height to match the screen size of the +video that we capture um which is + + align:start position:0% +video that we capture um which is + + + align:start position:0% +video that we capture um which is +usually 1920 x 1080 pixels so you want + + align:start position:0% +usually 1920 x 1080 pixels so you want + + + align:start position:0% +usually 1920 x 1080 pixels so you want +to make sure the width is 1920 the + + align:start position:0% +to make sure the width is 1920 the + + + align:start position:0% +to make sure the width is 1920 the +height is 1080 and the units are + + align:start position:0% +height is 1080 and the units are + + + align:start position:0% +height is 1080 and the units are +pixels uh um and you can keep the color + + align:start position:0% +pixels uh um and you can keep the color + + + align:start position:0% +pixels uh um and you can keep the color +mode um and the pixel grid the same and + + align:start position:0% +mode um and the pixel grid the same and + + + align:start position:0% +mode um and the pixel grid the same and +you press okay and your screen should + + align:start position:0% +you press okay and your screen should + + + align:start position:0% +you press okay and your screen should +look something like this + + align:start position:0% +look something like this + + + align:start position:0% +look something like this +um and this is just the drawing surface + + align:start position:0% +um and this is just the drawing surface + + + align:start position:0% +um and this is just the drawing surface +on which you're going to + + align:start position:0% + + + + align:start position:0% + +work + + align:start position:0% +work + + + align:start position:0% +work +um do you guys want to follow along or + + align:start position:0% +um do you guys want to follow along or + + + align:start position:0% +um do you guys want to follow along or +should I just keep + + align:start position:0% +should I just keep + + + align:start position:0% +should I just keep +going from + + align:start position:0% +going from + + + align:start position:0% +going from +here nod + + align:start position:0% + + + + align:start position:0% + +how about um sorry can you go through + + align:start position:0% +how about um sorry can you go through + + + align:start position:0% +how about um sorry can you go through +just like drawing a single shape and + + align:start position:0% +just like drawing a single shape and + + + align:start position:0% +just like drawing a single shape and +then maybe like draw like a person's + + align:start position:0% +then maybe like draw like a person's + + + align:start position:0% +then maybe like draw like a person's +face and then export it out of an + + align:start position:0% +face and then export it out of an + + + align:start position:0% +face and then export it out of an +illustrator and then animate it in After + + align:start position:0% +illustrator and then animate it in After + + + align:start position:0% +illustrator and then animate it in After +Effects and the that's a yeah okay yeah + + align:start position:0% +Effects and the that's a yeah okay yeah + + + align:start position:0% +Effects and the that's a yeah okay yeah +oh is that what you g to do yeah yeah + + align:start position:0% +oh is that what you g to do yeah yeah + + + align:start position:0% +oh is that what you g to do yeah yeah +okay sorry go ahead yeah yeah no worries + + align:start position:0% +okay sorry go ahead yeah yeah no worries + + + align:start position:0% +okay sorry go ahead yeah yeah no worries +um so this is just going over some basic + + align:start position:0% +um so this is just going over some basic + + + align:start position:0% +um so this is just going over some basic +tools um I like expanding the right tool + + align:start position:0% +tools um I like expanding the right tool + + + align:start position:0% +tools um I like expanding the right tool +panel just so I can see everything um + + align:start position:0% +panel just so I can see everything um + + + align:start position:0% +panel just so I can see everything um +especially the layers that's um a tool I + + align:start position:0% +especially the layers that's um a tool I + + + align:start position:0% +especially the layers that's um a tool I +use a lot um basic things that you're + + align:start position:0% +use a lot um basic things that you're + + + align:start position:0% +use a lot um basic things that you're +going to use are the paintbrush this is + + align:start position:0% +going to use are the paintbrush this is + + + align:start position:0% +going to use are the paintbrush this is +how you mimic writing on your tablet so + + align:start position:0% +how you mimic writing on your tablet so + + + align:start position:0% +how you mimic writing on your tablet so +you + + align:start position:0% +you + + + align:start position:0% +you +can mimic your handwriting um you can + + align:start position:0% +can mimic your handwriting um you can + + + align:start position:0% +can mimic your handwriting um you can +draw basic shapes with this um but they + + align:start position:0% +draw basic shapes with this um but they + + + align:start position:0% +draw basic shapes with this um but they +appear + + align:start position:0% +appear + + + align:start position:0% +appear +as lines so everything in illustrator is + + align:start position:0% +as lines so everything in illustrator is + + + align:start position:0% +as lines so everything in illustrator is +a vector so this is a solid object um + + align:start position:0% + + + + align:start position:0% + +yeah and then if you want to make + + align:start position:0% +yeah and then if you want to make + + + align:start position:0% +yeah and then if you want to make +shapes um there's a rectangle tool over + + align:start position:0% +shapes um there's a rectangle tool over + + + align:start position:0% +shapes um there's a rectangle tool over +here and you can hold down on it and + + align:start position:0% +here and you can hold down on it and + + + align:start position:0% +here and you can hold down on it and +find other shapes um and then you can + + align:start position:0% +find other shapes um and then you can + + + align:start position:0% +find other shapes um and then you can +just drag to place it um if you want to + + align:start position:0% +just drag to place it um if you want to + + + align:start position:0% +just drag to place it um if you want to +change the Border color or the color of + + align:start position:0% +change the Border color or the color of + + + align:start position:0% +change the Border color or the color of +an individual line you can click on this + + align:start position:0% +an individual line you can click on this + + + align:start position:0% +an individual line you can click on this +this is stroke color um double click and + + align:start position:0% +this is stroke color um double click and + + + align:start position:0% +this is stroke color um double click and +it'll just give you a fuller color + + align:start position:0% +it'll just give you a fuller color + + + align:start position:0% +it'll just give you a fuller color +spectrum + + align:start position:0% +spectrum + + + align:start position:0% +spectrum +you can select anything and if you want + + align:start position:0% +you can select anything and if you want + + + align:start position:0% +you can select anything and if you want +to change the fill right now the fill + + align:start position:0% +to change the fill right now the fill + + + align:start position:0% +to change the fill right now the fill +the white box with the red line through + + align:start position:0% +the white box with the red line through + + + align:start position:0% +the white box with the red line through +it means that it's transparent um but + + align:start position:0% +it means that it's transparent um but + + + align:start position:0% +it means that it's transparent um but +you can choose any color you want and + + align:start position:0% +you can choose any color you want and + + + align:start position:0% +you can choose any color you want and +it'll like change the shape um if you + + align:start position:0% +it'll like change the shape um if you + + + align:start position:0% +it'll like change the shape um if you +want to draw a free form shape the + + align:start position:0% +want to draw a free form shape the + + + align:start position:0% +want to draw a free form shape the +pencil tool will connect lines to make a + + align:start position:0% +pencil tool will connect lines to make a + + + align:start position:0% +pencil tool will connect lines to make a +a potentially solid object so if you + + align:start position:0% +a potentially solid object so if you + + + align:start position:0% +a potentially solid object so if you +want to make like an irregular polygon + + align:start position:0% +want to make like an irregular polygon + + + align:start position:0% +want to make like an irregular polygon +or + + align:start position:0% +or + + + align:start position:0% +or +some other shape the pencil tool + + align:start position:0% +some other shape the pencil tool + + + align:start position:0% +some other shape the pencil tool +automatically connects them even if you + + align:start position:0% +automatically connects them even if you + + + align:start position:0% +automatically connects them even if you +don't completely draw them together you + + align:start position:0% +don't completely draw them together you + + + align:start position:0% +don't completely draw them together you +can also redraw lines + + align:start position:0% +can also redraw lines + + + align:start position:0% +can also redraw lines +sometimes if you draw them in the same + + align:start position:0% +sometimes if you draw them in the same + + + align:start position:0% +sometimes if you draw them in the same +direction that you originally did so you + + align:start position:0% +direction that you originally did so you + + + align:start position:0% +direction that you originally did so you +can like + + align:start position:0% +can like + + + align:start position:0% +can like +adjust the border of a shape + + align:start position:0% +adjust the border of a shape + + + align:start position:0% +adjust the border of a shape +slightly + + align:start position:0% +slightly + + + align:start position:0% +slightly +um what else the black selection tool + + align:start position:0% +um what else the black selection tool + + + align:start position:0% +um what else the black selection tool +can help you select entire objects um + + align:start position:0% +can help you select entire objects um + + + align:start position:0% +can help you select entire objects um +you highlight + + align:start position:0% +you highlight + + + align:start position:0% +you highlight +I'm sorry no no + + align:start position:0% +I'm sorry no no + + + align:start position:0% +I'm sorry no no +worries is it not recording yeah it was + + align:start position:0% +worries is it not recording yeah it was + + + align:start position:0% +worries is it not recording yeah it was +not + + align:start position:0% +not + + + align:start position:0% +not +okay do you want me to do a quick time + + align:start position:0% +okay do you want me to do a quick time + + + align:start position:0% +okay do you want me to do a quick time +recording this backup as a backup + + align:start position:0% + + + + align:start position:0% + +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +okay um okay so the black + + align:start position:0% + + + + align:start position:0% + +the black selection Arrow can help you + + align:start position:0% +the black selection Arrow can help you + + + align:start position:0% +the black selection Arrow can help you +select entire objects or you can drag to + + align:start position:0% +select entire objects or you can drag to + + + align:start position:0% +select entire objects or you can drag to +select groups of objects um the white + + align:start position:0% +select groups of objects um the white + + + align:start position:0% +select groups of objects um the white +selection Arrow you can select + + align:start position:0% +selection Arrow you can select + + + align:start position:0% +selection Arrow you can select +individual points on objects so you can + + align:start position:0% +individual points on objects so you can + + + align:start position:0% +individual points on objects so you can +um like select a point on the path and + + align:start position:0% +um like select a point on the path and + + + align:start position:0% +um like select a point on the path and +then move it around so you can warp a + + align:start position:0% +then move it around so you can warp a + + + align:start position:0% +then move it around so you can warp a +line that already + + align:start position:0% +line that already + + + align:start position:0% +line that already +exists um and like change its direction + + align:start position:0% +exists um and like change its direction + + + align:start position:0% +exists um and like change its direction +and things like that um let me think + + align:start position:0% +and things like that um let me think + + + align:start position:0% +and things like that um let me think +the ey dropper tool is useful if you + + align:start position:0% +the ey dropper tool is useful if you + + + align:start position:0% +the ey dropper tool is useful if you +let's say I + + align:start position:0% + + + + align:start position:0% + +was um took a paintbrush and I had a + + align:start position:0% +was um took a paintbrush and I had a + + + align:start position:0% +was um took a paintbrush and I had a +specific stroke weight I had a + + align:start position:0% + + + + align:start position:0% + +specific color that I was using to draw + + align:start position:0% +specific color that I was using to draw + + + align:start position:0% +specific color that I was using to draw +I don't know a circle or + + align:start position:0% +I don't know a circle or + + + align:start position:0% +I don't know a circle or +spiral um and + + align:start position:0% + + + + align:start position:0% + +then I reverted black back to like black + + align:start position:0% +then I reverted black back to like black + + + align:start position:0% +then I reverted black back to like black +and one point um but I want to go back + + align:start position:0% +and one point um but I want to go back + + + align:start position:0% +and one point um but I want to go back +to that + + align:start position:0% +to that + + + align:start position:0% +to that +size and color um the eye dropper tool + + align:start position:0% +size and color um the eye dropper tool + + + align:start position:0% +size and color um the eye dropper tool +will hold both those information so if I + + align:start position:0% +will hold both those information so if I + + + align:start position:0% +will hold both those information so if I +just ey dropper that then it'll turn + + align:start position:0% +just ey dropper that then it'll turn + + + align:start position:0% +just ey dropper that then it'll turn +blue and eight point brush but if I ey + + align:start position:0% +blue and eight point brush but if I ey + + + align:start position:0% +blue and eight point brush but if I ey +drop the black then it'll go back to one + + align:start position:0% +drop the black then it'll go back to one + + + align:start position:0% +drop the black then it'll go back to one +point in black um so it just saves you + + align:start position:0% +point in black um so it just saves you + + + align:start position:0% +point in black um so it just saves you +some time if you want to completely + + align:start position:0% +some time if you want to completely + + + align:start position:0% +some time if you want to completely +recreate something the last thing that's + + align:start position:0% +recreate something the last thing that's + + + align:start position:0% +recreate something the last thing that's +important in illustrator is + + align:start position:0% +important in illustrator is + + + align:start position:0% +important in illustrator is +layers um I usually divide up my + + align:start position:0% +layers um I usually divide up my + + + align:start position:0% +layers um I usually divide up my +Project based on like types of objects + + align:start position:0% +Project based on like types of objects + + + align:start position:0% +Project based on like types of objects +so if I was doing this from scratch I + + align:start position:0% +so if I was doing this from scratch I + + + align:start position:0% +so if I was doing this from scratch I +would probably put all the stuff I drew + + align:start position:0% +would probably put all the stuff I drew + + + align:start position:0% +would probably put all the stuff I drew +with a paintbrush on one layer um all + + align:start position:0% +with a paintbrush on one layer um all + + + align:start position:0% +with a paintbrush on one layer um all +the shapes on a separate layer um you + + align:start position:0% +the shapes on a separate layer um you + + + align:start position:0% +the shapes on a separate layer um you +create a new layer just by clicking this + + align:start position:0% +create a new layer just by clicking this + + + align:start position:0% +create a new layer just by clicking this +new little page here and it's basically + + align:start position:0% +new little page here and it's basically + + + align:start position:0% +new little page here and it's basically +just a way to group objects and + + align:start position:0% +just a way to group objects and + + + align:start position:0% +just a way to group objects and +manipulate them independently from each + + align:start position:0% +manipulate them independently from each + + + align:start position:0% +manipulate them independently from each +other + + align:start position:0% +other + + + align:start position:0% +other +um + + align:start position:0% +um + + + align:start position:0% +um +so for example I will move this square + + align:start position:0% +so for example I will move this square + + + align:start position:0% +so for example I will move this square +into Layer Two and I'll just animate + + align:start position:0% +into Layer Two and I'll just animate + + + align:start position:0% +into Layer Two and I'll just animate +using Layer Two + + align:start position:0% + + + + align:start position:0% + +um and you can + + align:start position:0% +um and you can + + + align:start position:0% +um and you can +toggle um a lock on each layer so if I + + align:start position:0% +toggle um a lock on each layer so if I + + + align:start position:0% +toggle um a lock on each layer so if I +put a lock on layer one that means I + + align:start position:0% +put a lock on layer one that means I + + + align:start position:0% +put a lock on layer one that means I +can't do anything to these objects like + + align:start position:0% +can't do anything to these objects like + + + align:start position:0% +can't do anything to these objects like +I can't manipulate them accidentally and + + align:start position:0% +I can't manipulate them accidentally and + + + align:start position:0% +I can't manipulate them accidentally and +the eyeball triggers whether you can see + + align:start position:0% +the eyeball triggers whether you can see + + + align:start position:0% +the eyeball triggers whether you can see +it or not so sometimes I you want to + + align:start position:0% +it or not so sometimes I you want to + + + align:start position:0% +it or not so sometimes I you want to +draw something in one layer and then you + + align:start position:0% +draw something in one layer and then you + + + align:start position:0% +draw something in one layer and then you +create a couple more on top of it um and + + align:start position:0% +create a couple more on top of it um and + + + align:start position:0% +create a couple more on top of it um and +you don't want to see the original one + + align:start position:0% +you don't want to see the original one + + + align:start position:0% +you don't want to see the original one +and I usually name my layer something to + + align:start position:0% +and I usually name my layer something to + + + align:start position:0% +and I usually name my layer something to +remind me what they are um for the + + align:start position:0% +remind me what they are um for the + + + align:start position:0% +remind me what they are um for the +purposes of After Effects just so um + + align:start position:0% +purposes of After Effects just so um + + + align:start position:0% +purposes of After Effects just so um +it's less confusing when I get there so + + align:start position:0% +it's less confusing when I get there so + + + align:start position:0% +it's less confusing when I get there so +this would be text and Layer Two will be + + align:start position:0% +this would be text and Layer Two will be + + + align:start position:0% +this would be text and Layer Two will be +rectangle if I can spell + + align:start position:0% +rectangle if I can spell + + + align:start position:0% +rectangle if I can spell +rectangle + + align:start position:0% +rectangle + + + align:start position:0% +rectangle +um that's pretty much all there is to + + align:start position:0% +um that's pretty much all there is to + + + align:start position:0% +um that's pretty much all there is to +know about illustrator you can save the + + align:start position:0% +know about illustrator you can save the + + + align:start position:0% +know about illustrator you can save the +files um it'll save as aai which is + + align:start position:0% +files um it'll save as aai which is + + + align:start position:0% +files um it'll save as aai which is +important when you animate something + + align:start position:0% +important when you animate something + + + align:start position:0% +important when you animate something +save it somewhere where you're going to + + align:start position:0% +save it somewhere where you're going to + + + align:start position:0% +save it somewhere where you're going to +remember where it + + align:start position:0% +remember where it + + + align:start position:0% +remember where it +is um and you can just keep the default + + align:start position:0% +is um and you can just keep the default + + + align:start position:0% +is um and you can just keep the default +settings if okay so here's where it's + + align:start position:0% +settings if okay so here's where it's + + + align:start position:0% +settings if okay so here's where it's +going to Branch off if you want a still + + align:start position:0% +going to Branch off if you want a still + + + align:start position:0% +going to Branch off if you want a still +transparent image over your video or an + + align:start position:0% +transparent image over your video or an + + + align:start position:0% +transparent image over your video or an +animation um if you just want a still + + align:start position:0% +animation um if you just want a still + + + align:start position:0% +animation um if you just want a still +transparent image you can draw it an + + align:start position:0% +transparent image you can draw it an + + + align:start position:0% +transparent image you can draw it an +illustrator like this um just click file + + align:start position:0% +illustrator like this um just click file + + + align:start position:0% +illustrator like this um just click file +export um and it'll automatically go to + + align:start position:0% +export um and it'll automatically go to + + + align:start position:0% +export um and it'll automatically go to +PNG um click use artboards because that + + align:start position:0% +PNG um click use artboards because that + + + align:start position:0% +PNG um click use artboards because that +preserves the screen dimensions that you + + align:start position:0% +preserves the screen dimensions that you + + + align:start position:0% +preserves the screen dimensions that you +specified in the + + align:start position:0% +specified in the + + + align:start position:0% +specified in the +beginning um and you click export and + + align:start position:0% +beginning um and you click export and + + + align:start position:0% +beginning um and you click export and +it'll give you this popup window and + + align:start position:0% +it'll give you this popup window and + + + align:start position:0% +it'll give you this popup window and +here is where you can choose whether you + + align:start position:0% +here is where you can choose whether you + + + align:start position:0% +here is where you can choose whether you +want like a white background a black + + align:start position:0% +want like a white background a black + + + align:start position:0% +want like a white background a black +background or a transparent um which is + + align:start position:0% +background or a transparent um which is + + + align:start position:0% +background or a transparent um which is +really nice if you just want like a text + + align:start position:0% +really nice if you just want like a text + + + align:start position:0% +really nice if you just want like a text +overlay on your video because you + + align:start position:0% +overlay on your video because you + + + align:start position:0% +overlay on your video because you +automatically have an image with Vector + + align:start position:0% +automatically have an image with Vector + + + align:start position:0% +automatically have an image with Vector +art in it or vector words and a + + align:start position:0% +art in it or vector words and a + + + align:start position:0% +art in it or vector words and a +transparent background um and you just + + align:start position:0% +transparent background um and you just + + + align:start position:0% +transparent background um and you just +click okay and then your image will be + + align:start position:0% +click okay and then your image will be + + + align:start position:0% +click okay and then your image will be +exported I think mine's in my downloads + + align:start position:0% +exported I think mine's in my downloads + + + align:start position:0% +exported I think mine's in my downloads +folder yeah just as like a PNG file + + align:start position:0% +folder yeah just as like a PNG file + + + align:start position:0% +folder yeah just as like a PNG file +which you can import into iMovie or + + align:start position:0% +which you can import into iMovie or + + + align:start position:0% +which you can import into iMovie or +Premiere or um Final Cut Pro and overlay + + align:start position:0% +Premiere or um Final Cut Pro and overlay + + + align:start position:0% +Premiere or um Final Cut Pro and overlay +it just like another video track or an + + align:start position:0% +it just like another video track or an + + + align:start position:0% +it just like another video track or an +image um okay that is everything for + + align:start position:0% +image um okay that is everything for + + + align:start position:0% +image um okay that is everything for +illustrator so I will close + + align:start position:0% + + + + align:start position:0% + +that now + + align:start position:0% +that now + + + align:start position:0% +that now +if you want to animate um animate in + + align:start position:0% +if you want to animate um animate in + + + align:start position:0% +if you want to animate um animate in +After + + align:start position:0% +After + + + align:start position:0% +After +Effects most likely um you can also + + align:start position:0% +Effects most likely um you can also + + + align:start position:0% +Effects most likely um you can also +learn flash animation but that's a + + align:start position:0% +learn flash animation but that's a + + + align:start position:0% +learn flash animation but that's a +different concept behind it + + align:start position:0% +different concept behind it + + + align:start position:0% +different concept behind it +um so the way you start a composition in + + align:start position:0% +um so the way you start a composition in + + + align:start position:0% +um so the way you start a composition in +After Effects and import your images + + align:start position:0% +After Effects and import your images + + + align:start position:0% +After Effects and import your images +that you started in illustrator um you + + align:start position:0% +that you started in illustrator um you + + + align:start position:0% +that you started in illustrator um you +exit out of the initial window when it + + align:start position:0% +exit out of the initial window when it + + + align:start position:0% +exit out of the initial window when it +asks you to create a new composition + + align:start position:0% +asks you to create a new composition + + + align:start position:0% +asks you to create a new composition +because we're going to just import our + + align:start position:0% +because we're going to just import our + + + align:start position:0% +because we're going to just import our +files from illustrator as a new + + align:start position:0% +files from illustrator as a new + + + align:start position:0% +files from illustrator as a new +composition so you just double click in + + align:start position:0% +composition so you just double click in + + + align:start position:0% +composition so you just double click in +the project window and it'll give you a + + align:start position:0% +the project window and it'll give you a + + + align:start position:0% +the project window and it'll give you a +popup window that says import file I'm + + align:start position:0% +popup window that says import file I'm + + + align:start position:0% +popup window that says import file I'm +sure there's another way to do this but + + align:start position:0% +sure there's another way to do this but + + + align:start position:0% +sure there's another way to do this but +this is just how I was taught um you can + + align:start position:0% +this is just how I was taught um you can + + + align:start position:0% +this is just how I was taught um you can +probably go file open or something like + + align:start position:0% +probably go file open or something like + + + align:start position:0% +probably go file open or something like +that um go to wherever you saved your + + align:start position:0% +that um go to wherever you saved your + + + align:start position:0% +that um go to wherever you saved your +illustrator file um enable all + + align:start position:0% +illustrator file um enable all + + + align:start position:0% +illustrator file um enable all +acceptable files and then import it as a + + align:start position:0% +acceptable files and then import it as a + + + align:start position:0% +acceptable files and then import it as a +composition um that just means it will + + align:start position:0% +composition um that just means it will + + + align:start position:0% +composition um that just means it will +process each layer in your illustrator + + align:start position:0% +process each layer in your illustrator + + + align:start position:0% +process each layer in your illustrator +file as a different layer in your + + align:start position:0% +file as a different layer in your + + + align:start position:0% +file as a different layer in your +composition which will be important when + + align:start position:0% +composition which will be important when + + + align:start position:0% +composition which will be important when +it comes to + + align:start position:0% +it comes to + + + align:start position:0% +it comes to +animating um and then from here you can + + align:start position:0% +animating um and then from here you can + + + align:start position:0% +animating um and then from here you can +alter your composition settings my + + align:start position:0% +alter your composition settings my + + + align:start position:0% +alter your composition settings my +tablet as side + + align:start position:0% + + + + align:start position:0% + +um and and you can name your composition + + align:start position:0% +um and and you can name your composition + + + align:start position:0% +um and and you can name your composition +um it'll automatically adopt the name + + align:start position:0% +um it'll automatically adopt the name + + + align:start position:0% +um it'll automatically adopt the name +that you named your illustrator file um + + align:start position:0% +that you named your illustrator file um + + + align:start position:0% +that you named your illustrator file um +you can customize the width and the + + align:start position:0% +you can customize the width and the + + + align:start position:0% +you can customize the width and the +height which should be the same + + align:start position:0% +height which should be the same + + + align:start position:0% +height which should be the same +dimensions that you specified before um + + align:start position:0% +dimensions that you specified before um + + + align:start position:0% +dimensions that you specified before um +you want it to be in square pixels + + align:start position:0% +you want it to be in square pixels + + + align:start position:0% +you want it to be in square pixels +sometimes it defaults + + align:start position:0% +sometimes it defaults + + + align:start position:0% +sometimes it defaults +to different size and I think + + align:start position:0% +to different size and I think + + + align:start position:0% +to different size and I think +rectangular pixels are silly and they + + align:start position:0% +rectangular pixels are silly and they + + + align:start position:0% +rectangular pixels are silly and they +mess up how your video is going to look + + align:start position:0% +mess up how your video is going to look + + + align:start position:0% +mess up how your video is going to look +eventually or how your animations relate + + align:start position:0% +eventually or how your animations relate + + + align:start position:0% +eventually or how your animations relate +to your video the frame rate is + + align:start position:0% +to your video the frame rate is + + + align:start position:0% +to your video the frame rate is +important because it allows you to match + + align:start position:0% +important because it allows you to match + + + align:start position:0% +important because it allows you to match +up your animation exactly to your video + + align:start position:0% +up your animation exactly to your video + + + align:start position:0% +up your animation exactly to your video +um in Adobe Premiere the frame rate is + + align:start position:0% +um in Adobe Premiere the frame rate is + + + align:start position:0% +um in Adobe Premiere the frame rate is +30 the default for After Effects is 25 + + align:start position:0% +30 the default for After Effects is 25 + + + align:start position:0% +30 the default for After Effects is 25 +and that messed me up on my first + + align:start position:0% +and that messed me up on my first + + + align:start position:0% +and that messed me up on my first +project because I was trying to time + + align:start position:0% +project because I was trying to time + + + align:start position:0% +project because I was trying to time +everything and then it was off by + + align:start position:0% +everything and then it was off by + + + align:start position:0% +everything and then it was off by +um five frames per second which is + + align:start position:0% +um five frames per second which is + + + align:start position:0% +um five frames per second which is +really frustrating um I don't know what + + align:start position:0% +really frustrating um I don't know what + + + align:start position:0% +really frustrating um I don't know what +they are for imove your final cut but I + + align:start position:0% +they are for imove your final cut but I + + + align:start position:0% +they are for imove your final cut but I +would check um when you go in before you + + align:start position:0% +would check um when you go in before you + + + align:start position:0% +would check um when you go in before you +start your project + + align:start position:0% +start your project + + + align:start position:0% +start your project +um okay + + align:start position:0% + + + + align:start position:0% + +um I set the background color to white + + align:start position:0% +um I set the background color to white + + + align:start position:0% +um I set the background color to white +just so I can see everything um because + + align:start position:0% +just so I can see everything um because + + + align:start position:0% +just so I can see everything um because +I usually draw with a white background + + align:start position:0% +I usually draw with a white background + + + align:start position:0% +I usually draw with a white background +in illustrator if you want to set the + + align:start position:0% +in illustrator if you want to set the + + + align:start position:0% +in illustrator if you want to set the +default background in illustrator to + + align:start position:0% +default background in illustrator to + + + align:start position:0% +default background in illustrator to +Black and do white text and set that as + + align:start position:0% +Black and do white text and set that as + + + align:start position:0% +Black and do white text and set that as +transparent in front of your video um + + align:start position:0% +transparent in front of your video um + + + align:start position:0% +transparent in front of your video um +then a black background would make more + + align:start position:0% +then a black background would make more + + + align:start position:0% +then a black background would make more +sense this background color does not + + align:start position:0% +sense this background color does not + + + align:start position:0% +sense this background color does not +export with the video though so your + + align:start position:0% +export with the video though so your + + + align:start position:0% +export with the video though so your +animations are still transparent it's + + align:start position:0% +animations are still transparent it's + + + align:start position:0% +animations are still transparent it's +just so you can see things in After + + align:start position:0% +just so you can see things in After + + + align:start position:0% +just so you can see things in After +Effects um and usually what I do before + + align:start position:0% +Effects um and usually what I do before + + + align:start position:0% +Effects um and usually what I do before +I start an After Effects project is I + + align:start position:0% +I start an After Effects project is I + + + align:start position:0% +I start an After Effects project is I +look at how long the audio is for the + + align:start position:0% +look at how long the audio is for the + + + align:start position:0% +look at how long the audio is for the +portion that I want to animate so for + + align:start position:0% +portion that I want to animate so for + + + align:start position:0% +portion that I want to animate so for +example I was working with Andrea + + align:start position:0% +example I was working with Andrea + + + align:start position:0% +example I was working with Andrea +yesterday and she wanted a goat um + + align:start position:0% +yesterday and she wanted a goat um + + + align:start position:0% +yesterday and she wanted a goat um +during one of her lines when she says + + align:start position:0% +during one of her lines when she says + + + align:start position:0% +during one of her lines when she says +and the force of a mountain goat jumping + + align:start position:0% +and the force of a mountain goat jumping + + + align:start position:0% +and the force of a mountain goat jumping +on your teeth is some amount of Newtons + + align:start position:0% +on your teeth is some amount of Newtons + + + align:start position:0% +on your teeth is some amount of Newtons +or whatever the line is um and you look + + align:start position:0% +or whatever the line is um and you look + + + align:start position:0% +or whatever the line is um and you look +at the duration of how long it takes you + + align:start position:0% +at the duration of how long it takes you + + + align:start position:0% +at the duration of how long it takes you +to say that line in your editing + + align:start position:0% +to say that line in your editing + + + align:start position:0% +to say that line in your editing +software and that's how long I set my + + align:start position:0% +software and that's how long I set my + + + align:start position:0% +software and that's how long I set my +duration of my animation to be so it's + + align:start position:0% +duration of my animation to be so it's + + + align:start position:0% +duration of my animation to be so it's +really easy it's really like modular I'm + + align:start position:0% +really easy it's really like modular I'm + + + align:start position:0% +really easy it's really like modular I'm +animating for this part of the video and + + align:start position:0% +animating for this part of the video and + + + align:start position:0% +animating for this part of the video and +I have this much space to do it in um + + align:start position:0% +I have this much space to do it in um + + + align:start position:0% +I have this much space to do it in um +and because I don't have an audio track + + align:start position:0% +and because I don't have an audio track + + + align:start position:0% +and because I don't have an audio track +right now I'm just going to set it to 15 + + align:start position:0% +right now I'm just going to set it to 15 + + + align:start position:0% +right now I'm just going to set it to 15 +seconds so that's good um then you can + + align:start position:0% +seconds so that's good um then you can + + + align:start position:0% +seconds so that's good um then you can +double click on your composition to open + + align:start position:0% +double click on your composition to open + + + align:start position:0% +double click on your composition to open +it and this is going to be your display + + align:start position:0% +it and this is going to be your display + + + align:start position:0% +it and this is going to be your display +window this is your timeline it's where + + align:start position:0% +window this is your timeline it's where + + + align:start position:0% +window this is your timeline it's where +I guess the animation is taking place + + align:start position:0% +I guess the animation is taking place + + + align:start position:0% +I guess the animation is taking place +and you can see different things + + align:start position:0% +and you can see different things + + + align:start position:0% +and you can see different things +um and here's where your you're going to + + align:start position:0% +um and here's where your you're going to + + + align:start position:0% +um and here's where your you're going to +be doing a lot of the animation stuff + + align:start position:0% +be doing a lot of the animation stuff + + + align:start position:0% +be doing a lot of the animation stuff +this little options window I guess um + + align:start position:0% +this little options window I guess um + + + align:start position:0% +this little options window I guess um +you can still toggle the visibility just + + align:start position:0% +you can still toggle the visibility just + + + align:start position:0% +you can still toggle the visibility just +like you did in + + align:start position:0% +like you did in + + + align:start position:0% +like you did in +illustrator and so H let's say um I'm + + align:start position:0% +illustrator and so H let's say um I'm + + + align:start position:0% +illustrator and so H let's say um I'm +just going to show you how to animate + + align:start position:0% +just going to show you how to animate + + + align:start position:0% +just going to show you how to animate +this rectangle for example um so the + + align:start position:0% +this rectangle for example um so the + + + align:start position:0% +this rectangle for example um so the +first thing you want to do is right + + align:start position:0% +first thing you want to do is right + + + align:start position:0% +first thing you want to do is right +click on it and create shapes from the + + align:start position:0% +click on it and create shapes from the + + + align:start position:0% +click on it and create shapes from the +vector layer basically this just allows + + align:start position:0% +vector layer basically this just allows + + + align:start position:0% +vector layer basically this just allows +um after effects to take the vector + + align:start position:0% +um after effects to take the vector + + + align:start position:0% +um after effects to take the vector +shapes or objects that you created an + + align:start position:0% +shapes or objects that you created an + + + align:start position:0% +shapes or objects that you created an +illustrator and translate it into a + + align:start position:0% +illustrator and translate it into a + + + align:start position:0% +illustrator and translate it into a +manipul + + align:start position:0% +manipul + + + align:start position:0% +manipul +manipulatable format um for After + + align:start position:0% +manipulatable format um for After + + + align:start position:0% +manipulatable format um for After +Effects um so then you have this new + + align:start position:0% +Effects um so then you have this new + + + align:start position:0% +Effects um so then you have this new +item object I don't know called + + align:start position:0% +item object I don't know called + + + align:start position:0% +item object I don't know called +rectangle outlines um and you can look + + align:start position:0% +rectangle outlines um and you can look + + + align:start position:0% +rectangle outlines um and you can look +inside and their contents if you had + + align:start position:0% +inside and their contents if you had + + + align:start position:0% +inside and their contents if you had +multiple objects in the same layer you'd + + align:start position:0% +multiple objects in the same layer you'd + + + align:start position:0% +multiple objects in the same layer you'd +have multiple groups but I just have the + + align:start position:0% +have multiple groups but I just have the + + + align:start position:0% +have multiple groups but I just have the +one rectangle so I only have group + + align:start position:0% +one rectangle so I only have group + + + align:start position:0% +one rectangle so I only have group +one um and so in order to move this what + + align:start position:0% +one um and so in order to move this what + + + align:start position:0% +one um and so in order to move this what +I'm going to do is open up group one and + + align:start position:0% +I'm going to do is open up group one and + + + align:start position:0% +I'm going to do is open up group one and +I + + align:start position:0% +I + + + align:start position:0% +I +have um different + + align:start position:0% +have um different + + + align:start position:0% +have um different +options and you guys are going to be + + align:start position:0% +options and you guys are going to be + + + align:start position:0% +options and you guys are going to be +doing a lot of transform animations um + + align:start position:0% +doing a lot of transform animations um + + + align:start position:0% +doing a lot of transform animations um +so these are things like if you want + + align:start position:0% +so these are things like if you want + + + align:start position:0% +so these are things like if you want +something to move around on the screen + + align:start position:0% +something to move around on the screen + + + align:start position:0% +something to move around on the screen +if you want something to change in size + + align:start position:0% +if you want something to change in size + + + align:start position:0% +if you want something to change in size +or rotate or things like that um so what + + align:start position:0% +or rotate or things like that um so what + + + align:start position:0% +or rotate or things like that um so what +you're going to do for if you wanted + + align:start position:0% +you're going to do for if you wanted + + + align:start position:0% +you're going to do for if you wanted +let's say I wanted this rectangle to + + align:start position:0% +let's say I wanted this rectangle to + + + align:start position:0% +let's say I wanted this rectangle to +move across the screen and grow + + align:start position:0% +move across the screen and grow + + + align:start position:0% +move across the screen and grow +bigger the things that I will and and in + + align:start position:0% +bigger the things that I will and and in + + + align:start position:0% +bigger the things that I will and and in +After Effects you want to think in key + + align:start position:0% +After Effects you want to think in key + + + align:start position:0% +After Effects you want to think in key +frames so what does it look like at one + + align:start position:0% +frames so what does it look like at one + + + align:start position:0% +frames so what does it look like at one +point in the animation and then what do + + align:start position:0% +point in the animation and then what do + + + align:start position:0% +point in the animation and then what do +you want it to look like in two + + align:start position:0% +you want it to look like in two + + + align:start position:0% +you want it to look like in two +seconds um so right now this is where I + + align:start position:0% +seconds um so right now this is where I + + + align:start position:0% +seconds um so right now this is where I +want it to start so I'll click a little + + align:start position:0% +want it to start so I'll click a little + + + align:start position:0% +want it to start so I'll click a little +stopwatch on position and scale and + + align:start position:0% +stopwatch on position and scale and + + + align:start position:0% +stopwatch on position and scale and +these will set key frames for both + + align:start position:0% +these will set key frames for both + + + align:start position:0% +these will set key frames for both +position and scale so now after effects + + align:start position:0% +position and scale so now after effects + + + align:start position:0% +position and scale so now after effects +remembers where the rectangle is at this + + align:start position:0% +remembers where the rectangle is at this + + + align:start position:0% +remembers where the rectangle is at this +point in time then I'll set it forward + + align:start position:0% +point in time then I'll set it forward + + + align:start position:0% +point in time then I'll set it forward +to let's say 2 seconds I want in 2 + + align:start position:0% +to let's say 2 seconds I want in 2 + + + align:start position:0% +to let's say 2 seconds I want in 2 +seconds I want my rectangle to move and + + align:start position:0% +seconds I want my rectangle to move and + + + align:start position:0% +seconds I want my rectangle to move and +then it's as easy as dragging the + + align:start position:0% +then it's as easy as dragging the + + + align:start position:0% +then it's as easy as dragging the +rectangle to where you want it to be and + + align:start position:0% +rectangle to where you want it to be and + + + align:start position:0% +rectangle to where you want it to be and +then changing its size so let's say I + + align:start position:0% +then changing its size so let's say I + + + align:start position:0% +then changing its size so let's say I +want it to be really big like that and + + align:start position:0% +want it to be really big like that and + + + align:start position:0% +want it to be really big like that and +then once you make those changes after + + align:start position:0% +then once you make those changes after + + + align:start position:0% +then once you make those changes after +effects automatically sets another key + + align:start position:0% +effects automatically sets another key + + + align:start position:0% +effects automatically sets another key +frame for you in your + + align:start position:0% +frame for you in your + + + align:start position:0% +frame for you in your +timeline then you can review what you + + align:start position:0% +timeline then you can review what you + + + align:start position:0% +timeline then you can review what you +want the animation to do by dragging + + align:start position:0% +want the animation to do by dragging + + + align:start position:0% +want the animation to do by dragging +this back um and pushing space which is + + align:start position:0% +this back um and pushing space which is + + + align:start position:0% +this back um and pushing space which is +the same thing as play and then you can + + align:start position:0% +the same thing as play and then you can + + + align:start position:0% +the same thing as play and then you can +watch how over the two seconds it + + align:start position:0% +watch how over the two seconds it + + + align:start position:0% +watch how over the two seconds it +transitions from one point in space to + + align:start position:0% +transitions from one point in space to + + + align:start position:0% +transitions from one point in space to +another point in space and another one + + align:start position:0% +another point in space and another one + + + align:start position:0% +another point in space and another one +size to another size um you can edit and + + align:start position:0% +size to another size um you can edit and + + + align:start position:0% +size to another size um you can edit and +delete key frames you can add more in + + align:start position:0% +delete key frames you can add more in + + + align:start position:0% +delete key frames you can add more in +the middle let's say I wanted it to go + + align:start position:0% +the middle let's say I wanted it to go + + + align:start position:0% +the middle let's say I wanted it to go +up and left before I wanted it to go up + + align:start position:0% +up and left before I wanted it to go up + + + align:start position:0% +up and left before I wanted it to go up +and right um You can just set it to the + + align:start position:0% +and right um You can just set it to the + + + align:start position:0% +and right um You can just set it to the +middle of this animation and drag it up + + align:start position:0% +middle of this animation and drag it up + + + align:start position:0% +middle of this animation and drag it up +and left to where you would want it to + + align:start position:0% +and left to where you would want it to + + + align:start position:0% +and left to where you would want it to +be and then it'll keep scaling si uh the + + align:start position:0% +be and then it'll keep scaling si uh the + + + align:start position:0% +be and then it'll keep scaling si uh the +size at the same time but then it'll + + align:start position:0% +size at the same time but then it'll + + + align:start position:0% +size at the same time but then it'll +just adjust its position path in the new + + align:start position:0% + + + + align:start position:0% + +animation + + align:start position:0% +animation + + + align:start position:0% +animation +um and that's the really The Bare Bones + + align:start position:0% +um and that's the really The Bare Bones + + + align:start position:0% +um and that's the really The Bare Bones +of Animation um the one other thing you + + align:start position:0% +of Animation um the one other thing you + + + align:start position:0% +of Animation um the one other thing you +guys might use is let's + + align:start position:0% +guys might use is let's + + + align:start position:0% +guys might use is let's +see um if you want to group multiple + + align:start position:0% +see um if you want to group multiple + + + align:start position:0% +see um if you want to group multiple +items um and have them move at the same + + align:start position:0% +items um and have them move at the same + + + align:start position:0% +items um and have them move at the same +time for + + align:start position:0% +time for + + + align:start position:0% +time for +example + + align:start position:0% +example + + + align:start position:0% +example +um let's see I'm going to take my text + + align:start position:0% +um let's see I'm going to take my text + + + align:start position:0% +um let's see I'm going to take my text +layer create shapes from vector layer + + align:start position:0% +layer create shapes from vector layer + + + align:start position:0% +layer create shapes from vector layer +and now I have another layer of + + align:start position:0% +and now I have another layer of + + + align:start position:0% +and now I have another layer of +objects um except this one has many + + align:start position:0% +objects um except this one has many + + + align:start position:0% +objects um except this one has many +contents many groups of things that I + + align:start position:0% +contents many groups of things that I + + + align:start position:0% +contents many groups of things that I +can manipulate so let's say I want both + + align:start position:0% +can manipulate so let's say I want both + + + align:start position:0% +can manipulate so let's say I want both +these spirals to move at the same time + + align:start position:0% +these spirals to move at the same time + + + align:start position:0% +these spirals to move at the same time +um I haven't found a better way to do + + align:start position:0% +um I haven't found a better way to do + + + align:start position:0% +um I haven't found a better way to do +this but um so I learned that the + + align:start position:0% +this but um so I learned that the + + + align:start position:0% +this but um so I learned that the +spirals are groups 2 and + + align:start position:0% +spirals are groups 2 and + + + align:start position:0% +spirals are groups 2 and +three I can click on contents just to + + align:start position:0% +three I can click on contents just to + + + align:start position:0% +three I can click on contents just to +highlight everything add a new empty + + align:start position:0% +highlight everything add a new empty + + + align:start position:0% +highlight everything add a new empty +group and it's just labeled whatever the + + align:start position:0% +group and it's just labeled whatever the + + + align:start position:0% +group and it's just labeled whatever the +highest number like the one after the + + align:start position:0% +highest number like the one after the + + + align:start position:0% +highest number like the one after the +highest number you can rename it to + + align:start position:0% +highest number you can rename it to + + + align:start position:0% +highest number you can rename it to +something like spirals so you remember + + align:start position:0% +something like spirals so you remember + + + align:start position:0% +something like spirals so you remember +it um you can highlight both of + + align:start position:0% +it um you can highlight both of + + + align:start position:0% +it um you can highlight both of +these and just drag it into the new + + align:start position:0% +these and just drag it into the new + + + align:start position:0% +these and just drag it into the new +group + + align:start position:0% +group + + + align:start position:0% +group +and that way you can transform spirals + + align:start position:0% +and that way you can transform spirals + + + align:start position:0% +and that way you can transform spirals +as a unit you can um say I wanted them + + align:start position:0% +as a unit you can um say I wanted them + + + align:start position:0% +as a unit you can um say I wanted them +to + + align:start position:0% + + + + align:start position:0% + +rotate and so + + align:start position:0% +rotate and so + + + align:start position:0% +rotate and so +then oh God okay that's kind of + + align:start position:0% + + + + align:start position:0% + +rotating um and so it set the key frames + + align:start position:0% +rotating um and so it set the key frames + + + align:start position:0% +rotating um and so it set the key frames +for rotations but instead of just + + align:start position:0% +for rotations but instead of just + + + align:start position:0% +for rotations but instead of just +manipulating one spiral I have two + + align:start position:0% +manipulating one spiral I have two + + + align:start position:0% +manipulating one spiral I have two +grouped together and then the rectangle + + align:start position:0% +grouped together and then the rectangle + + + align:start position:0% +grouped together and then the rectangle +animation is still going + + align:start position:0% +animation is still going + + + align:start position:0% +animation is still going +um from + + align:start position:0% +um from + + + align:start position:0% +um from +before can you can you put to what do + + align:start position:0% +before can you can you put to what do + + + align:start position:0% +before can you can you put to what do +you mean put a point that on uh Pivot + + align:start position:0% +you mean put a point that on uh Pivot + + + align:start position:0% +you mean put a point that on uh Pivot +Point um I think so I don't usually + + align:start position:0% +Point um I think so I don't usually + + + align:start position:0% +Point um I think so I don't usually +rotate things in my animations I'm Pro + + align:start position:0% +rotate things in my animations I'm Pro + + + align:start position:0% +rotate things in my animations I'm Pro +let's see I think it's probably the + + align:start position:0% +let's see I think it's probably the + + + align:start position:0% +let's see I think it's probably the +Anchor + + align:start position:0% + + + + align:start position:0% + +Point CR + + align:start position:0% +Point CR + + + align:start position:0% +Point CR +yeah so that's the pivot point I don't + + align:start position:0% +yeah so that's the pivot point I don't + + + align:start position:0% +yeah so that's the pivot point I don't +know how to change that + + align:start position:0% +know how to change that + + + align:start position:0% +know how to change that +necessarily okay there you go you can + + align:start position:0% +necessarily okay there you go you can + + + align:start position:0% +necessarily okay there you go you can +just adjust it in relation to the Anchor + + align:start position:0% +just adjust it in relation to the Anchor + + + align:start position:0% +just adjust it in relation to the Anchor +Point so you can change this + + align:start position:0% + + + + align:start position:0% + +value yeah a lot of this is just playing + + align:start position:0% +value yeah a lot of this is just playing + + + align:start position:0% +value yeah a lot of this is just playing +around and seeing what you want to do + + align:start position:0% +around and seeing what you want to do + + + align:start position:0% +around and seeing what you want to do +you can ask me questions afterward and + + align:start position:0% +you can ask me questions afterward and + + + align:start position:0% +you can ask me questions afterward and +I'd be happy to like troubleshoot it + + align:start position:0% +I'd be happy to like troubleshoot it + + + align:start position:0% +I'd be happy to like troubleshoot it +with you + + align:start position:0% + + + + align:start position:0% + +um yeah so I guess that's how you pivot + + align:start position:0% +um yeah so I guess that's how you pivot + + + align:start position:0% +um yeah so I guess that's how you pivot +and so it'll maintain the rotation just + + align:start position:0% +and so it'll maintain the rotation just + + + align:start position:0% +and so it'll maintain the rotation just +around the smaller Anchor Point + + align:start position:0% +around the smaller Anchor Point + + + align:start position:0% +around the smaller Anchor Point +now + + align:start position:0% +now + + + align:start position:0% +now +um let's + + align:start position:0% + + + + align:start position:0% + +see + + align:start position:0% +see + + + align:start position:0% +see +um + + align:start position:0% +um + + + align:start position:0% +um +if this is might be useful um so if you + + align:start position:0% +if this is might be useful um so if you + + + align:start position:0% +if this is might be useful um so if you +already go in and you have a lot of work + + align:start position:0% +already go in and you have a lot of work + + + align:start position:0% +already go in and you have a lot of work +um so for example in a different project + + align:start position:0% +um so for example in a different project + + + align:start position:0% +um so for example in a different project +what happened was I had the outline of a + + align:start position:0% +what happened was I had the outline of a + + + align:start position:0% +what happened was I had the outline of a +cell and I was showing contents of the + + align:start position:0% +cell and I was showing contents of the + + + align:start position:0% +cell and I was showing contents of the +nucleus and when I screened it to my + + align:start position:0% +nucleus and when I screened it to my + + + align:start position:0% +nucleus and when I screened it to my +project adviser she said it's great but + + align:start position:0% +project adviser she said it's great but + + + align:start position:0% +project adviser she said it's great but +we're not focusing on the nucleus of the + + align:start position:0% +we're not focusing on the nucleus of the + + + align:start position:0% +we're not focusing on the nucleus of the +cell and so I can't really see what's + + align:start position:0% +cell and so I can't really see what's + + + align:start position:0% +cell and so I can't really see what's +going on so I had already done all this + + align:start position:0% +going on so I had already done all this + + + align:start position:0% +going on so I had already done all this +animation with individual squiggles of + + align:start position:0% +animation with individual squiggles of + + + align:start position:0% +animation with individual squiggles of +DNA and proteins moving around in the + + align:start position:0% +DNA and proteins moving around in the + + + align:start position:0% +DNA and proteins moving around in the +nucleus and I wanted to preserve that + + align:start position:0% +nucleus and I wanted to preserve that + + + align:start position:0% +nucleus and I wanted to preserve that +animation but um I needed to just zoom + + align:start position:0% +animation but um I needed to just zoom + + + align:start position:0% +animation but um I needed to just zoom +in on everything and you can do this + + align:start position:0% +in on everything and you can do this + + + align:start position:0% +in on everything and you can do this +with a thing called a null + + align:start position:0% +with a thing called a null + + + align:start position:0% +with a thing called a null +object + + align:start position:0% +object + + + align:start position:0% +object +um see if I remember how to do this okay + + align:start position:0% +um see if I remember how to do this okay + + + align:start position:0% +um see if I remember how to do this okay +layer um new and then a null object and + + align:start position:0% +layer um new and then a null object and + + + align:start position:0% +layer um new and then a null object and +so it'll appear in here as just null one + + align:start position:0% +so it'll appear in here as just null one + + + align:start position:0% +so it'll appear in here as just null one +and basically it's a way to group + + align:start position:0% +and basically it's a way to group + + + align:start position:0% +and basically it's a way to group +multiple animations at the same time + + align:start position:0% +multiple animations at the same time + + + align:start position:0% +multiple animations at the same time +um you can just leave it named n one I + + align:start position:0% +um you can just leave it named n one I + + + align:start position:0% +um you can just leave it named n one I +guess but so let's say I want the spiral + + align:start position:0% +guess but so let's say I want the spiral + + + align:start position:0% +guess but so let's say I want the spiral +and the rectangle to both be smaller + + align:start position:0% +and the rectangle to both be smaller + + + align:start position:0% +and the rectangle to both be smaller +because they're both way too big um so + + align:start position:0% +because they're both way too big um so + + + align:start position:0% +because they're both way too big um so +then you can set these + + align:start position:0% +then you can set these + + + align:start position:0% +then you can set these +layers as um you can set the null object + + align:start position:0% +layers as um you can set the null object + + + align:start position:0% +layers as um you can set the null object +as the parent of these layers this is + + align:start position:0% +as the parent of these layers this is + + + align:start position:0% +as the parent of these layers this is +say parent and you can have a drop down + + align:start position:0% +say parent and you can have a drop down + + + align:start position:0% +say parent and you can have a drop down +menu and so you can set both these + + align:start position:0% +menu and so you can set both these + + + align:start position:0% +menu and so you can set both these +layers to have their parent as null one + + align:start position:0% +layers to have their parent as null one + + + align:start position:0% +layers to have their parent as null one +and then you can animate null one as + + align:start position:0% +and then you can animate null one as + + + align:start position:0% +and then you can animate null one as +though it were an independent object so + + align:start position:0% +though it were an independent object so + + + align:start position:0% +though it were an independent object so +let's + + align:start position:0% + + + + align:start position:0% + +say I just want the scale of everything + + align:start position:0% +say I just want the scale of everything + + + align:start position:0% +say I just want the scale of everything +to go down so because those are both + + align:start position:0% +to go down so because those are both + + + align:start position:0% +to go down so because those are both +grouped under under the null layer then + + align:start position:0% +grouped under under the null layer then + + + align:start position:0% +grouped under under the null layer then +the scale goes down or or you can + + align:start position:0% +the scale goes down or or you can + + + align:start position:0% +the scale goes down or or you can +animate it independently so let's say I + + align:start position:0% +animate it independently so let's say I + + + align:start position:0% +animate it independently so let's say I +want the scale at 100% but as the + + align:start position:0% +want the scale at 100% but as the + + + align:start position:0% +want the scale at 100% but as the +rectangle grows I want everything to + + align:start position:0% +rectangle grows I want everything to + + + align:start position:0% +rectangle grows I want everything to +shrink because it got too big and so + + align:start position:0% +shrink because it got too big and so + + + align:start position:0% +shrink because it got too big and so +then you can turn the scale down of + + align:start position:0% +then you can turn the scale down of + + + align:start position:0% +then you can turn the scale down of +everything so when I run the animation + + align:start position:0% +everything so when I run the animation + + + align:start position:0% +everything so when I run the animation +the rectangle's going to grow the + + align:start position:0% +the rectangle's going to grow the + + + align:start position:0% +the rectangle's going to grow the +spirals are going to rotate but then + + align:start position:0% +spirals are going to rotate but then + + + align:start position:0% +spirals are going to rotate but then +everything because it's all grouped + + align:start position:0% +everything because it's all grouped + + + align:start position:0% +everything because it's all grouped +under the null layer is going to + + align:start position:0% + + + + align:start position:0% + +shrink um so I guess those are the + + align:start position:0% +shrink um so I guess those are the + + + align:start position:0% +shrink um so I guess those are the +basics of it um once you have your After + + align:start position:0% +basics of it um once you have your After + + + align:start position:0% +basics of it um once you have your After +Effects file um you can I would save it + + align:start position:0% +Effects file um you can I would save it + + + align:start position:0% +Effects file um you can I would save it +as something just so you don't lose + + align:start position:0% + + + + align:start position:0% + +anything + + align:start position:0% +anything + + + align:start position:0% +anything +um and then you can do one of two things + + align:start position:0% +um and then you can do one of two things + + + align:start position:0% +um and then you can do one of two things +um so if you want to um edit in + + align:start position:0% + + + + align:start position:0% + +Premiere you can + + align:start position:0% +Premiere you can + + + align:start position:0% +Premiere you can +start um Adobe products are really nice + + align:start position:0% +start um Adobe products are really nice + + + align:start position:0% +start um Adobe products are really nice +where where they auto update to each + + align:start position:0% +where where they auto update to each + + + align:start position:0% +where where they auto update to each +other so if you change the Illustrator + + align:start position:0% +other so if you change the Illustrator + + + align:start position:0% +other so if you change the Illustrator +files that um make up the composition + + align:start position:0% +files that um make up the composition + + + align:start position:0% +files that um make up the composition +and after effects then your After + + align:start position:0% +and after effects then your After + + + align:start position:0% +and after effects then your After +Effects will change to reflect those + + align:start position:0% +Effects will change to reflect those + + + align:start position:0% +Effects will change to reflect those +changes so like if you messed up drawing + + align:start position:0% +changes so like if you messed up drawing + + + align:start position:0% +changes so like if you messed up drawing +something or you want a shape to look a + + align:start position:0% +something or you want a shape to look a + + + align:start position:0% +something or you want a shape to look a +little bit different um you can up if + + align:start position:0% +little bit different um you can up if + + + align:start position:0% +little bit different um you can up if +you update the illustrator file your + + align:start position:0% +you update the illustrator file your + + + align:start position:0% +you update the illustrator file your +After Effects project will also update + + align:start position:0% +After Effects project will also update + + + align:start position:0% +After Effects project will also update +same thing with your After Effects + + align:start position:0% +same thing with your After Effects + + + align:start position:0% +same thing with your After Effects +project and premiere + + align:start position:0% +project and premiere + + + align:start position:0% +project and premiere +um so if I have a premier project I can + + align:start position:0% +um so if I have a premier project I can + + + align:start position:0% +um so if I have a premier project I can +just drag oh crap do this + + align:start position:0% +just drag oh crap do this + + + align:start position:0% +just drag oh crap do this +backwards you can drag your After + + align:start position:0% +backwards you can drag your After + + + align:start position:0% +backwards you can drag your After +Effects composition into Premiere just + + align:start position:0% +Effects composition into Premiere just + + + align:start position:0% +Effects composition into Premiere just +to import media and then I have my test + + align:start position:0% +to import media and then I have my test + + + align:start position:0% +to import media and then I have my test +animation and I can drop it here to + + align:start position:0% +animation and I can drop it here to + + + align:start position:0% +animation and I can drop it here to +create a sequence um and so right now + + align:start position:0% +create a sequence um and so right now + + + align:start position:0% +create a sequence um and so right now +because it's transparent um I can't see + + align:start position:0% +because it's transparent um I can't see + + + align:start position:0% +because it's transparent um I can't see +anything but if I were + + align:start position:0% +anything but if I were + + + align:start position:0% +anything but if I were +to add add a color + + align:start position:0% +to add add a color + + + align:start position:0% +to add add a color +match + + align:start position:0% +match + + + align:start position:0% +match +in light blue it's going to be really + + align:start position:0% +in light blue it's going to be really + + + align:start position:0% +in light blue it's going to be really +garish and add it on the video layer + + align:start position:0% +garish and add it on the video layer + + + align:start position:0% +garish and add it on the video layer +below the animation then it'll appear so + + align:start position:0% +below the animation then it'll appear so + + + align:start position:0% +below the animation then it'll appear so +like the animation itself is + + align:start position:0% +like the animation itself is + + + align:start position:0% +like the animation itself is +transparent if you don't want to edit um + + align:start position:0% +transparent if you don't want to edit um + + + align:start position:0% +transparent if you don't want to edit um +and so now if I make changes in After + + align:start position:0% +and so now if I make changes in After + + + align:start position:0% +and so now if I make changes in After +Effects it'll automatically update those + + align:start position:0% +Effects it'll automatically update those + + + align:start position:0% +Effects it'll automatically update those +changes in Premiere which I find really + + align:start position:0% +changes in Premiere which I find really + + + align:start position:0% +changes in Premiere which I find really +handy as I'm video editing and switching + + align:start position:0% +handy as I'm video editing and switching + + + align:start position:0% +handy as I'm video editing and switching +back and forth if you don't want to edit + + align:start position:0% +back and forth if you don't want to edit + + + align:start position:0% +back and forth if you don't want to edit +in Premiere that is totally + + align:start position:0% +in Premiere that is totally + + + align:start position:0% +in Premiere that is totally +fine um and you just need to export your + + align:start position:0% +fine um and you just need to export your + + + align:start position:0% +fine um and you just need to export your +composition um I was just playing around + + align:start position:0% +composition um I was just playing around + + + align:start position:0% +composition um I was just playing around +with this earlier usually I don't export + + align:start position:0% +with this earlier usually I don't export + + + align:start position:0% +with this earlier usually I don't export +so I don't necessarily have the ideal + + align:start position:0% +so I don't necessarily have the ideal + + + align:start position:0% +so I don't necessarily have the ideal +settings for it um but we can play + + align:start position:0% +settings for it um but we can play + + + align:start position:0% +settings for it um but we can play +around and see what works so file export + + align:start position:0% +around and see what works so file export + + + align:start position:0% +around and see what works so file export +to Adobe Media + + align:start position:0% + + + + align:start position:0% + +encoder um and then it adds it + + align:start position:0% +encoder um and then it adds it + + + align:start position:0% +encoder um and then it adds it +automatically to the CU and you can + + align:start position:0% +automatically to the CU and you can + + + align:start position:0% +automatically to the CU and you can +choose um preset export settings over + + align:start position:0% +choose um preset export settings over + + + align:start position:0% +choose um preset export settings over +here um I created a preset for the edex + + align:start position:0% +here um I created a preset for the edex + + + align:start position:0% +here um I created a preset for the edex +videos that I'm working on and so I + + align:start position:0% +videos that I'm working on and so I + + + align:start position:0% +videos that I'm working on and so I +usually just select that um and then + + align:start position:0% +usually just select that um and then + + + align:start position:0% +usually just select that um and then +once + + align:start position:0% +once + + + align:start position:0% +once +you do all that then you can just push + + align:start position:0% +you do all that then you can just push + + + align:start position:0% +you do all that then you can just push +play um and then the media encoder does + + align:start position:0% +play um and then the media encoder does + + + align:start position:0% +play um and then the media encoder does +its thing I don't know exactly what it + + align:start position:0% +its thing I don't know exactly what it + + + align:start position:0% +its thing I don't know exactly what it +does I think it's like a combination of + + align:start position:0% +does I think it's like a combination of + + + align:start position:0% +does I think it's like a combination of +rendering and just making sure + + align:start position:0% +rendering and just making sure + + + align:start position:0% +rendering and just making sure +I don't know changing the file format + + align:start position:0% +I don't know changing the file format + + + align:start position:0% +I don't know changing the file format +from + + align:start position:0% +from + + + align:start position:0% +from +a uh After Effects project to in this + + align:start position:0% +a uh After Effects project to in this + + + align:start position:0% +a uh After Effects project to in this +case an mp4 file so for a lot of you + + align:start position:0% +case an mp4 file so for a lot of you + + + align:start position:0% +case an mp4 file so for a lot of you +guys I'm imagining you want to do + + align:start position:0% +guys I'm imagining you want to do + + + align:start position:0% +guys I'm imagining you want to do +animation overlay right so you can't do + + align:start position:0% +animation overlay right so you can't do + + + align:start position:0% +animation overlay right so you can't do +that in stuff like iMovie so what you + + align:start position:0% +that in stuff like iMovie so what you + + + align:start position:0% +that in stuff like iMovie so what you +will have to do which is like a super + + align:start position:0% +will have to do which is like a super + + + align:start position:0% +will have to do which is like a super +janky work EG is you create the + + align:start position:0% +janky work EG is you create the + + + align:start position:0% +janky work EG is you create the +animation and after effects you go in + + align:start position:0% +animation and after effects you go in + + + align:start position:0% +animation and after effects you go in +Premiere and that's where you overlay it + + align:start position:0% +Premiere and that's where you overlay it + + + align:start position:0% +Premiere and that's where you overlay it +on top of your liveaction footage and + + align:start position:0% +on top of your liveaction footage and + + + align:start position:0% +on top of your liveaction footage and +then you export that little chunk into + + align:start position:0% +then you export that little chunk into + + + align:start position:0% +then you export that little chunk into +your movie Project does that make sense + + align:start position:0% +your movie Project does that make sense + + + align:start position:0% +your movie Project does that make sense +to you guys so would you mind showing + + align:start position:0% +to you guys so would you mind showing + + + align:start position:0% +to you guys so would you mind showing +real quick how to do it in Premiere + + align:start position:0% +real quick how to do it in Premiere + + + align:start position:0% +real quick how to do it in Premiere +where you overlay or you overlay an + + align:start position:0% +where you overlay or you overlay an + + + align:start position:0% +where you overlay or you overlay an +animation on top of your live action + + align:start position:0% +animation on top of your live action + + + align:start position:0% +animation on top of your live action +footage + + align:start position:0% +footage + + + align:start position:0% +footage +sure + + align:start position:0% + + + + align:start position:0% + +um let's so it's basically just doing + + align:start position:0% +um let's so it's basically just doing + + + align:start position:0% +um let's so it's basically just doing +what I was doing besides um and just + + align:start position:0% +what I was doing besides um and just + + + align:start position:0% +what I was doing besides um and just +using something besides the color mat I + + align:start position:0% +using something besides the color mat I + + + align:start position:0% +using something besides the color mat I +will see if I have any movies on my + + align:start position:0% +will see if I have any movies on my + + + align:start position:0% +will see if I have any movies on my +computer I don't know if I do so if you + + align:start position:0% +computer I don't know if I do so if you + + + align:start position:0% +computer I don't know if I do so if you +are holding your hands out like this how + + align:start position:0% +are holding your hands out like this how + + + align:start position:0% +are holding your hands out like this how +do you um what's the best way to time + + align:start position:0% +do you um what's the best way to time + + + align:start position:0% +do you um what's the best way to time +and place the + + align:start position:0% +and place the + + + align:start position:0% +and place the +animations basically have to draw them + + align:start position:0% +animations basically have to draw them + + + align:start position:0% +animations basically have to draw them +without seeing a background in After + + align:start position:0% +without seeing a background in After + + + align:start position:0% +without seeing a background in After +Effects + + align:start position:0% +Effects + + + align:start position:0% +Effects +right yeah + + align:start position:0% +right yeah + + + align:start position:0% +right yeah +um so the + + align:start position:0% +um so the + + + align:start position:0% +um so the +way let's see okay I have a + + align:start position:0% + + + + align:start position:0% + +video um + + align:start position:0% +video um + + + align:start position:0% +video um +okay so the way I + + align:start position:0% +okay so the way I + + + align:start position:0% +okay so the way I +would animate an After Effects is my + + align:start position:0% +would animate an After Effects is my + + + align:start position:0% +would animate an After Effects is my +window still open okay + + align:start position:0% +window still open okay + + + align:start position:0% +window still open okay +cool is to use the time codes so + + align:start position:0% +cool is to use the time codes so + + + align:start position:0% +cool is to use the time codes so +Premiere has a Time code and it's right + + align:start position:0% +Premiere has a Time code and it's right + + + align:start position:0% +Premiere has a Time code and it's right +here and it um matches up with I'm turn + + align:start position:0% +here and it um matches up with I'm turn + + + align:start position:0% +here and it um matches up with I'm turn +off my volume + + align:start position:0% +off my volume + + + align:start position:0% +off my volume +where um the movie + + align:start position:0% +where um the movie + + + align:start position:0% +where um the movie +is so for example + + align:start position:0% +is so for example + + + align:start position:0% +is so for example +if drag this + + align:start position:0% +if drag this + + + align:start position:0% +if drag this +down so right now like the animation is + + align:start position:0% +down so right now like the animation is + + + align:start position:0% +down so right now like the animation is +overlaid for my movie and the formatting + + align:start position:0% +overlaid for my movie and the formatting + + + align:start position:0% +overlaid for my movie and the formatting +is weird cuz I didn't do the movie + + align:start position:0% +is weird cuz I didn't do the movie + + + align:start position:0% +is weird cuz I didn't do the movie +first let's + + align:start position:0% + + + + align:start position:0% + +see okay um what I would do is let's say + + align:start position:0% +see okay um what I would do is let's say + + + align:start position:0% +see okay um what I would do is let's say +for + + align:start position:0% +for + + + align:start position:0% +for +example I wanted at four uh 5 Seconds + + align:start position:0% +example I wanted at four uh 5 Seconds + + + align:start position:0% +example I wanted at four uh 5 Seconds +something to happen like something to + + align:start position:0% +something to happen like something to + + + align:start position:0% +something to happen like something to +pop up above my hand then I would take + + align:start position:0% +pop up above my hand then I would take + + + align:start position:0% +pop up above my hand then I would take +note of the time code or whenever you + + align:start position:0% +note of the time code or whenever you + + + align:start position:0% +note of the time code or whenever you +raise your hand in the video so let's + + align:start position:0% +raise your hand in the video so let's + + + align:start position:0% +raise your hand in the video so let's +say it was at 11 seconds um + + align:start position:0% +say it was at 11 seconds um + + + align:start position:0% +say it was at 11 seconds um +and 24 + + align:start position:0% + + + + align:start position:0% + +frames um + + align:start position:0% +frames um + + + align:start position:0% +frames um +then you go back + + align:start position:0% +then you go back + + + align:start position:0% +then you go back +into Adobe um After Effects and you can + + align:start position:0% +into Adobe um After Effects and you can + + + align:start position:0% +into Adobe um After Effects and you can +scroll over to 11 frames and make sure + + align:start position:0% +scroll over to 11 frames and make sure + + + align:start position:0% +scroll over to 11 frames and make sure +the time code here is listed here um and + + align:start position:0% +the time code here is listed here um and + + + align:start position:0% +the time code here is listed here um and +so you just switch back and forth and + + align:start position:0% +so you just switch back and forth and + + + align:start position:0% +so you just switch back and forth and +adjust the time code of your animations + + align:start position:0% +adjust the time code of your animations + + + align:start position:0% +adjust the time code of your animations +to the time code where you want it to + + align:start position:0% +to the time code where you want it to + + + align:start position:0% +to the time code where you want it to +appear in the + + align:start position:0% +appear in the + + + align:start position:0% +appear in the +video + + align:start position:0% +video + + + align:start position:0% +video +um and you can drag key frames to adjust + + align:start position:0% +um and you can drag key frames to adjust + + + align:start position:0% +um and you can drag key frames to adjust +that so like if I say well the rectangle + + align:start position:0% +that so like if I say well the rectangle + + + align:start position:0% +that so like if I say well the rectangle +move too fast in this video um I + + align:start position:0% +move too fast in this video um I + + + align:start position:0% +move too fast in this video um I +actually want the animation to end at + + align:start position:0% +actually want the animation to end at + + + align:start position:0% +actually want the animation to end at +329 instead of 2 seconds I can drag my + + align:start position:0% +329 instead of 2 seconds I can drag my + + + align:start position:0% +329 instead of 2 seconds I can drag my +cursor to + + align:start position:0% + + + + align:start position:0% + +3 29 and then just drag the key frame + + align:start position:0% +3 29 and then just drag the key frame + + + align:start position:0% +3 29 and then just drag the key frame +frame to match it that's usually how I + + align:start position:0% +frame to match it that's usually how I + + + align:start position:0% +frame to match it that's usually how I +do it just because it's a lot easier to + + align:start position:0% +do it just because it's a lot easier to + + + align:start position:0% +do it just because it's a lot easier to +visualize um and then it will + + align:start position:0% +visualize um and then it will + + + align:start position:0% +visualize um and then it will +automatically update in here and the + + align:start position:0% +automatically update in here and the + + + align:start position:0% +automatically update in here and the +animation just got a lot + + align:start position:0% +animation just got a lot + + + align:start position:0% +animation just got a lot +longer and so now when I push play + + align:start position:0% +longer and so now when I push play + + + align:start position:0% +longer and so now when I push play +instead of taking two seconds it's still + + align:start position:0% +instead of taking two seconds it's still + + + align:start position:0% +instead of taking two seconds it's still +going until + + align:start position:0% +going until + + + align:start position:0% +going until +3:29 + + align:start position:0% +3:29 + + + align:start position:0% +3:29 +um yeah it's a lot of playing around I + + align:start position:0% +um yeah it's a lot of playing around I + + + align:start position:0% +um yeah it's a lot of playing around I +don't have uh like a really really + + align:start position:0% +don't have uh like a really really + + + align:start position:0% +don't have uh like a really really +concrete method of doing it and I'm + + align:start position:0% +concrete method of doing it and I'm + + + align:start position:0% +concrete method of doing it and I'm +still learning + + align:start position:0% +still learning + + + align:start position:0% +still learning +animation too so + + align:start position:0% +animation too so + + + align:start position:0% +animation too so +um yeah I don't have the perfect answer + + align:start position:0% +um yeah I don't have the perfect answer + + + align:start position:0% +um yeah I don't have the perfect answer +but usually it's a lot of switching + + align:start position:0% +but usually it's a lot of switching + + + align:start position:0% +but usually it's a lot of switching +between Windows which is why when you + + align:start position:0% +between Windows which is why when you + + + align:start position:0% +between Windows which is why when you +have two monitors it's really nice + + align:start position:0% +have two monitors it's really nice + + + align:start position:0% +have two monitors it's really nice +um but a lot of just like checking the + + align:start position:0% +um but a lot of just like checking the + + + align:start position:0% +um but a lot of just like checking the +time code exactly and making little + + align:start position:0% +time code exactly and making little + + + align:start position:0% +time code exactly and making little +adjustments at a time first you do it's + + align:start position:0% +adjustments at a time first you do it's + + + align:start position:0% +adjustments at a time first you do it's +kind of like how you edit a movie you + + align:start position:0% +kind of like how you edit a movie you + + + align:start position:0% +kind of like how you edit a movie you +start with a rough cut you start with a + + align:start position:0% +start with a rough cut you start with a + + + align:start position:0% +start with a rough cut you start with a +rough animation of what you want and + + align:start position:0% +rough animation of what you want and + + + align:start position:0% +rough animation of what you want and +then you can adjust the key frames to + + align:start position:0% +then you can adjust the key frames to + + + align:start position:0% +then you can adjust the key frames to +time it to the video that you're working + + align:start position:0% +time it to the video that you're working + + + align:start position:0% +time it to the video that you're working +with so I think the thing that'll be + + align:start position:0% +with so I think the thing that'll be + + + align:start position:0% +with so I think the thing that'll be +most productive for you guys is if you + + align:start position:0% +most productive for you guys is if you + + + align:start position:0% +most productive for you guys is if you +attempt to do your own animation and + + align:start position:0% +attempt to do your own animation and + + + align:start position:0% +attempt to do your own animation and +then if you run into problems email St + + align:start position:0% +then if you run into problems email St + + + align:start position:0% +then if you run into problems email St +um or you can email me we'll be around + + align:start position:0% +um or you can email me we'll be around + + + align:start position:0% +um or you can email me we'll be around +tomorrow if people are working and I'll + + align:start position:0% +tomorrow if people are working and I'll + + + align:start position:0% +tomorrow if people are working and I'll +be on campus tomorrow actually if you + + align:start position:0% +be on campus tomorrow actually if you + + + align:start position:0% +be on campus tomorrow actually if you +need help um but I think the most + + align:start position:0% +need help um but I think the most + + + align:start position:0% +need help um but I think the most +efficient route is if you try a little + + align:start position:0% +efficient route is if you try a little + + + align:start position:0% +efficient route is if you try a little +bit on your own first and then when + + align:start position:0% +bit on your own first and then when + + + align:start position:0% +bit on your own first and then when +specific questions pop up you + + align:start position:0% +specific questions pop up you + + + align:start position:0% +specific questions pop up you +can yeah and if you have anything + + align:start position:0% +can yeah and if you have anything + + + align:start position:0% +can yeah and if you have anything +specific in mind that you don't think + + align:start position:0% +specific in mind that you don't think + + + align:start position:0% +specific in mind that you don't think +you can accomplish with what I've taught + + align:start position:0% +you can accomplish with what I've taught + + + align:start position:0% +you can accomplish with what I've taught +you so far then you can definitely come + + align:start position:0% +you so far then you can definitely come + + + align:start position:0% +you so far then you can definitely come +talk to me or I can come over and talk + + align:start position:0% +talk to me or I can come over and talk + + + align:start position:0% +talk to me or I can come over and talk +to you and we can talk through what your + + align:start position:0% +to you and we can talk through what your + + + align:start position:0% +to you and we can talk through what your +picture was for animating something and + + align:start position:0% +picture was for animating something and + + + align:start position:0% +picture was for animating something and +how you can best do that either using + + align:start position:0% +how you can best do that either using + + + align:start position:0% +how you can best do that either using +the tools that I just taught you or + + align:start position:0% +the tools that I just taught you or + + + align:start position:0% +the tools that I just taught you or +using other things like I know how to + + align:start position:0% +using other things like I know how to + + + align:start position:0% +using other things like I know how to +mimic handwriting to write out a word + + align:start position:0% +mimic handwriting to write out a word + + + align:start position:0% +mimic handwriting to write out a word +and I don't know if that's necessary for + + align:start position:0% +and I don't know if that's necessary for + + + align:start position:0% +and I don't know if that's necessary for +any of you but like that's a thing that + + align:start position:0% +any of you but like that's a thing that + + + align:start position:0% +any of you but like that's a thing that +you can do in After Effects it's just a + + align:start position:0% +you can do in After Effects it's just a + + + align:start position:0% +you can do in After Effects it's just a +little more complicated than what I've + + align:start position:0% +little more complicated than what I've + + + align:start position:0% +little more complicated than what I've +shown you so far + + align:start position:0% + + + + align:start position:0% + +I have two questions one of them is um + + align:start position:0% +I have two questions one of them is um + + + align:start position:0% +I have two questions one of them is um +I've used a premium Pro before but then + + align:start position:0% +I've used a premium Pro before but then + + + align:start position:0% +I've used a premium Pro before but then +the sizing because I'm not sure when I + + align:start position:0% +the sizing because I'm not sure when I + + + align:start position:0% +the sizing because I'm not sure when I +do in PR Pro it looks like the sizing is + + align:start position:0% +do in PR Pro it looks like the sizing is + + + align:start position:0% +do in PR Pro it looks like the sizing is +correct however when I exported it to + + align:start position:0% +correct however when I exported it to + + + align:start position:0% +correct however when I exported it to +external video the sizing was wrong so + + align:start position:0% +external video the sizing was wrong so + + + align:start position:0% +external video the sizing was wrong so +is that setting um for exporting from + + align:start position:0% +is that setting um for exporting from + + + align:start position:0% +is that setting um for exporting from +Premiere um let's see I mean like if I + + align:start position:0% +Premiere um let's see I mean like if I + + + align:start position:0% +Premiere um let's see I mean like if I +see if I see the screen like this yes I + + align:start position:0% +see if I see the screen like this yes I + + + align:start position:0% +see if I see the screen like this yes I +think that all this is is this + + align:start position:0% +think that all this is is this + + + align:start position:0% +think that all this is is this +everything that's in the screen that + + align:start position:0% +everything that's in the screen that + + + align:start position:0% +everything that's in the screen that +will be shown in the in the actual video + + align:start position:0% +will be shown in the in the actual video + + + align:start position:0% +will be shown in the in the actual video +yeah so right now because so what this + + align:start position:0% +yeah so right now because so what this + + + align:start position:0% +yeah so right now because so what this +is I recorded this movie on my camera on + + align:start position:0% +is I recorded this movie on my camera on + + + align:start position:0% +is I recorded this movie on my camera on +my computer which is lower quality than + + align:start position:0% +my computer which is lower quality than + + + align:start position:0% +my computer which is lower quality than +the camera than your camcorders which + + align:start position:0% +the camera than your camcorders which + + + align:start position:0% +the camera than your camcorders which +should record in 1920 by 1080 um so like + + align:start position:0% +should record in 1920 by 1080 um so like + + + align:start position:0% +should record in 1920 by 1080 um so like +right now this like this on this in the + + align:start position:0% +right now this like this on this in the + + + align:start position:0% +right now this like this on this in the +upper right hand corner is what's going + + align:start position:0% +upper right hand corner is what's going + + + align:start position:0% +upper right hand corner is what's going +to be exported so the if I exported it + + align:start position:0% +to be exported so the if I exported it + + + align:start position:0% +to be exported so the if I exported it +right now it would export with this + + align:start position:0% +right now it would export with this + + + align:start position:0% +right now it would export with this +weird black border + + align:start position:0% +weird black border + + + align:start position:0% +weird black border +because my video is smaller than this + + align:start position:0% +because my video is smaller than this + + + align:start position:0% +because my video is smaller than this +composition so it's preferable to expand + + align:start position:0% +composition so it's preferable to expand + + + align:start position:0% +composition so it's preferable to expand +the screen can we expand the video yeah + + align:start position:0% +the screen can we expand the video yeah + + + align:start position:0% +the screen can we expand the video yeah +you can you can individually so if I + + align:start position:0% +you can you can individually so if I + + + align:start position:0% +you can you can individually so if I +take out the you can double click and + + align:start position:0% +take out the you can double click and + + + align:start position:0% +take out the you can double click and +like this is how you digitally Zoom oh + + align:start position:0% +like this is how you digitally Zoom oh + + + align:start position:0% +like this is how you digitally Zoom oh +basically you can manipulate it just + + align:start position:0% +basically you can manipulate it just + + + align:start position:0% +basically you can manipulate it just +like any other object and make it bigger + + align:start position:0% +like any other object and make it bigger + + + align:start position:0% +like any other object and make it bigger +so it fills the + + align:start position:0% +so it fills the + + + align:start position:0% +so it fills the +screen this will be in what do you mean + + align:start position:0% +screen this will be in what do you mean + + + align:start position:0% +screen this will be in what do you mean +this will be so this ex screen will be + + align:start position:0% +this will be so this ex screen will be + + + align:start position:0% +this will be so this ex screen will be +the one that + + align:start position:0% +the one that + + + align:start position:0% +the one that +yeah so whatever you see in this preview + + align:start position:0% +yeah so whatever you see in this preview + + + align:start position:0% +yeah so whatever you see in this preview +screen is what's going to come out when + + align:start position:0% +screen is what's going to come out when + + + align:start position:0% +screen is what's going to come out when +you export it um and then you can change + + align:start position:0% +you export it um and then you can change + + + align:start position:0% +you export it um and then you can change +export settings file export media um and + + align:start position:0% +export settings file export media um and + + + align:start position:0% +export settings file export media um and +you can like change the file type that + + align:start position:0% +you can like change the file type that + + + align:start position:0% +you can like change the file type that +you want it to be and the video format + + align:start position:0% +you want it to be and the video format + + + align:start position:0% +you want it to be and the video format +um I use the settings thatx needs to + + align:start position:0% +um I use the settings thatx needs to + + + align:start position:0% +um I use the settings thatx needs to +upload usually just because that's it + + align:start position:0% +upload usually just because that's it + + + align:start position:0% +upload usually just because that's it +works and it produces a high enough + + align:start position:0% +works and it produces a high enough + + + align:start position:0% +works and it produces a high enough +quality video um but if you know things + + align:start position:0% +quality video um but if you know things + + + align:start position:0% +quality video um but if you know things +about audio and video and things like + + align:start position:0% +about audio and video and things like + + + align:start position:0% +about audio and video and things like +that you can + + align:start position:0% +that you can + + + align:start position:0% +that you can +add like a a copyright encoded into the + + align:start position:0% +add like a a copyright encoded into the + + + align:start position:0% +add like a a copyright encoded into the +video itself if you really want to + + align:start position:0% +video itself if you really want to + + + align:start position:0% +video itself if you really want to +protect it and things like that but less + + align:start position:0% +protect it and things like that but less + + + align:start position:0% +protect it and things like that but less +necessary can I check the camera were + + align:start position:0% +necessary can I check the camera were + + + align:start position:0% +necessary can I check the camera were +given is how many + + align:start position:0% +given is how many + + + align:start position:0% +given is how many +frames I think it's 30 uh I'll double + + align:start position:0% +frames I think it's 30 uh I'll double + + + align:start position:0% +frames I think it's 30 uh I'll double +check + + align:start position:0% + + + + align:start position:0% + +it if I want to get a let's say I have a + + align:start position:0% +it if I want to get a let's say I have a + + + align:start position:0% +it if I want to get a let's say I have a +video I took a video yep but at the + + align:start position:0% +video I took a video yep but at the + + + align:start position:0% +video I took a video yep but at the +moment I want to cut that frame and + + align:start position:0% +moment I want to cut that frame and + + + align:start position:0% +moment I want to cut that frame and +extend that frame to make it like a + + align:start position:0% +extend that frame to make it like a + + + align:start position:0% +extend that frame to make it like a +picture because I want to explain the + + align:start position:0% +picture because I want to explain the + + + align:start position:0% +picture because I want to explain the +concept yeah so how do I do that um so + + align:start position:0% +concept yeah so how do I do that um so + + + align:start position:0% +concept yeah so how do I do that um so +this is something I can I don't know how + + align:start position:0% +this is something I can I don't know how + + + align:start position:0% +this is something I can I don't know how +to do it in Final Cut I know how to do + + align:start position:0% +to do it in Final Cut I know how to do + + + align:start position:0% +to do it in Final Cut I know how to do +it in Premiere so hypothetically in + + align:start position:0% +it in Premiere so hypothetically in + + + align:start position:0% +it in Premiere so hypothetically in +Premiere that's a bad frame to pause + + align:start position:0% +Premiere that's a bad frame to pause + + + align:start position:0% +Premiere that's a bad frame to pause +let's say I want to pause this Frame um + + align:start position:0% +let's say I want to pause this Frame um + + + align:start position:0% +let's say I want to pause this Frame um +you can do like there's a button here it + + align:start position:0% +you can do like there's a button here it + + + align:start position:0% +you can do like there's a button here it +just says export frame um I click it and + + align:start position:0% +just says export frame um I click it and + + + align:start position:0% +just says export frame um I click it and +then it's uh what do I want it to be + + align:start position:0% +then it's uh what do I want it to be + + + align:start position:0% +then it's uh what do I want it to be +it's + + align:start position:0% +it's + + + align:start position:0% +it's +like still face um and it's an I just + + align:start position:0% +like still face um and it's an I just + + + align:start position:0% +like still face um and it's an I just +wanted a JPEG I guess um and then this + + align:start position:0% +wanted a JPEG I guess um and then this + + + align:start position:0% +wanted a JPEG I guess um and then this +box just means uh you import it into the + + align:start position:0% +box just means uh you import it into the + + + align:start position:0% +box just means uh you import it into the +project automatically so no matter where + + align:start position:0% +project automatically so no matter where + + + align:start position:0% +project automatically so no matter where +it saves it in this case it's saving it + + align:start position:0% +it saves it in this case it's saving it + + + align:start position:0% +it saves it in this case it's saving it +in my premere folder and click okay and + + align:start position:0% +in my premere folder and click okay and + + + align:start position:0% +in my premere folder and click okay and +then it automatically appears as an + + align:start position:0% +then it automatically appears as an + + + align:start position:0% +then it automatically appears as an +image in your Media Browser area um and + + align:start position:0% +image in your Media Browser area um and + + + align:start position:0% +image in your Media Browser area um and +so then if you want to extend this Frame + + align:start position:0% +so then if you want to extend this Frame + + + align:start position:0% +so then if you want to extend this Frame +what I would personally do is use the + + align:start position:0% +what I would personally do is use the + + + align:start position:0% +what I would personally do is use the +razor tool + + align:start position:0% +razor tool + + + align:start position:0% +razor tool +cut the clip into two use the selection + + align:start position:0% +cut the clip into two use the selection + + + align:start position:0% +cut the clip into two use the selection +tool and drag this over so I have some + + align:start position:0% +tool and drag this over so I have some + + + align:start position:0% +tool and drag this over so I have some +space to include it and then include the + + align:start position:0% +space to include it and then include the + + + align:start position:0% +space to include it and then include the +still + + align:start position:0% +still + + + align:start position:0% +still +image and then just seal that Gap back + + align:start position:0% +image and then just seal that Gap back + + + align:start position:0% +image and then just seal that Gap back +up so now instead of just seeing me + + align:start position:0% +up so now instead of just seeing me + + + align:start position:0% +up so now instead of just seeing me +talk I should have brought it closer but + + align:start position:0% +talk I should have brought it closer but + + + align:start position:0% +talk I should have brought it closer but +then I'll talk I'll talk I'll talk and + + align:start position:0% +then I'll talk I'll talk I'll talk and + + + align:start position:0% +then I'll talk I'll talk I'll talk and +then the still frame will + + align:start position:0% +then the still frame will + + + align:start position:0% +then the still frame will +happen for like however many seconds you + + align:start position:0% +happen for like however many seconds you + + + align:start position:0% +happen for like however many seconds you +set it and you can adjust the size and + + align:start position:0% +set it and you can adjust the size and + + + align:start position:0% +set it and you can adjust the size and +timing of that and then the video will + + align:start position:0% +timing of that and then the video will + + + align:start position:0% +timing of that and then the video will +resume when you're ready for + + align:start position:0% +resume when you're ready for + + + align:start position:0% +resume when you're ready for +to um I don't exactly know what the FR + + align:start position:0% +to um I don't exactly know what the FR + + + align:start position:0% +to um I don't exactly know what the FR +rate of the Vixie is it records both in + + align:start position:0% +rate of the Vixie is it records both in + + + align:start position:0% +rate of the Vixie is it records both in +24 and 30 but if you open the video up + + align:start position:0% +24 and 30 but if you open the video up + + + align:start position:0% +24 and 30 but if you open the video up +in Qui time and you do command I it + + align:start position:0% +in Qui time and you do command I it + + + align:start position:0% +in Qui time and you do command I it +should tell you what it was recorded + + align:start position:0% +should tell you what it was recorded + + + align:start position:0% +should tell you what it was recorded +in and I just found that out by Googling + + align:start position:0% +in and I just found that out by Googling + + + align:start position:0% +in and I just found that out by Googling +it so yeah underestimate + + align:start position:0% + + + + align:start position:0% + +the are there any other questions about + + align:start position:0% +the are there any other questions about + + + align:start position:0% +the are there any other questions about +animating or editing or + + align:start position:0% +animating or editing or + + + align:start position:0% +animating or editing or +adobe I mean we're just going to stick + + align:start position:0% +adobe I mean we're just going to stick + + + align:start position:0% +adobe I mean we're just going to stick +around for the rest of today so if you + + align:start position:0% +around for the rest of today so if you + + + align:start position:0% +around for the rest of today so if you +just want to hang out here and work or + + align:start position:0% +just want to hang out here and work or + + + align:start position:0% +just want to hang out here and work or +you want to go back to the classroom and + + align:start position:0% +you want to go back to the classroom and + + + align:start position:0% +you want to go back to the classroom and +work we'll be + + align:start position:0% +work we'll be + + + align:start position:0% +work we'll be +around mhm \ No newline at end of file diff --git a/jMPc6-bcnH8.txt b/jMPc6-bcnH8.txt new file mode 100644 index 0000000000000000000000000000000000000000..f69db8f68712e1dd980a7c1b5debbacc8d987abb --- /dev/null +++ b/jMPc6-bcnH8.txt @@ -0,0 +1,1371 @@ +align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +i recommended the process of how to + + align:start position:0% +i recommended the process of how to + + + align:start position:0% +i recommended the process of how to +approach there's a i've + + align:start position:0% +approach there's a i've + + + align:start position:0% +approach there's a i've +as a + + align:start position:0% +as a + + + align:start position:0% +as a +the five steps or one way to think about + + align:start position:0% +the five steps or one way to think about + + + align:start position:0% +the five steps or one way to think about +you could have six or seven + + align:start position:0% +you could have six or seven + + + align:start position:0% +you could have six or seven +in the text i we wrote some time ago i + + align:start position:0% +in the text i we wrote some time ago i + + + align:start position:0% +in the text i we wrote some time ago i +we had seven put out because we went to + + align:start position:0% +we had seven put out because we went to + + + align:start position:0% +we had seven put out because we went to +a more complexity but um + + align:start position:0% +a more complexity but um + + + align:start position:0% +a more complexity but um +i'm now going to talk about these + + align:start position:0% +i'm now going to talk about these + + + align:start position:0% +i'm now going to talk about these +central five uh but it's mostly to cover + + align:start position:0% +central five uh but it's mostly to cover + + + align:start position:0% +central five uh but it's mostly to cover +the bases there's this five is not the + + align:start position:0% +the bases there's this five is not the + + + align:start position:0% +the bases there's this five is not the +magic + + align:start position:0% +magic + + + align:start position:0% +magic +number so the first one we need a + + align:start position:0% +number so the first one we need a + + + align:start position:0% +number so the first one we need a +valuation model + + align:start position:0% +valuation model + + + align:start position:0% +valuation model +and + + align:start position:0% +and + + + align:start position:0% +and +uh for those of you who are filling out + + align:start position:0% +uh for those of you who are filling out + + + align:start position:0% +uh for those of you who are filling out +your initial project form a number of + + align:start position:0% +your initial project form a number of + + + align:start position:0% +your initial project form a number of +you + + align:start position:0% +you + + + align:start position:0% +you +uh weren't quite understood that i + + align:start position:0% +uh weren't quite understood that i + + + align:start position:0% +uh weren't quite understood that i +what was involved when i asked about + + align:start position:0% +what was involved when i asked about + + + align:start position:0% +what was involved when i asked about +having a + + align:start position:0% +having a + + + align:start position:0% +having a +model of your system but you mean to + + align:start position:0% +model of your system but you mean to + + + align:start position:0% +model of your system but you mean to +have you need to have some way of saying + + align:start position:0% +have you need to have some way of saying + + + align:start position:0% +have you need to have some way of saying +okay + + align:start position:0% +okay + + + align:start position:0% +okay +if i design the model or i set up my + + align:start position:0% +if i design the model or i set up my + + + align:start position:0% +if i design the model or i set up my +model in my system in a particular place + + align:start position:0% +model in my system in a particular place + + + align:start position:0% +model in my system in a particular place +which is not only the machinery and the + + align:start position:0% +which is not only the machinery and the + + + align:start position:0% +which is not only the machinery and the +production of a process but also my my + + align:start position:0% +production of a process but also my my + + + align:start position:0% +production of a process but also my my +employees my marketing my sales my + + align:start position:0% +employees my marketing my sales my + + + align:start position:0% +employees my marketing my sales my +productivity and so forth you need to + + align:start position:0% +productivity and so forth you need to + + + align:start position:0% +productivity and so forth you need to +have a way of + + align:start position:0% +have a way of + + + align:start position:0% +have a way of +transforming those assets and your use + + align:start position:0% +transforming those assets and your use + + + align:start position:0% +transforming those assets and your use +into some kind of valuation it can be an + + align:start position:0% +into some kind of valuation it can be an + + + align:start position:0% +into some kind of valuation it can be an +economic valuation as in this particular + + align:start position:0% +economic valuation as in this particular + + + align:start position:0% +economic valuation as in this particular +case or it can be a performance + + align:start position:0% +case or it can be a performance + + + align:start position:0% +case or it can be a performance +evaluation i'm + + align:start position:0% +evaluation i'm + + + align:start position:0% +evaluation i'm +running an emergency + + align:start position:0% +running an emergency + + + align:start position:0% +running an emergency +medical effort to say come combat ebola + + align:start position:0% +medical effort to say come combat ebola + + + align:start position:0% +medical effort to say come combat ebola +uh how well do how quickly and how well + + align:start position:0% +uh how well do how quickly and how well + + + align:start position:0% +uh how well do how quickly and how well +do i contain the disease so it may be + + align:start position:0% +do i contain the disease so it may be + + + align:start position:0% +do i contain the disease so it may be +performance based rather than money + + align:start position:0% +performance based rather than money + + + align:start position:0% +performance based rather than money +based + + align:start position:0% +based + + + align:start position:0% +based +and in this case as from the garage i + + align:start position:0% +and in this case as from the garage i + + + align:start position:0% +and in this case as from the garage i +have things about the demand the + + align:start position:0% +have things about the demand the + + + align:start position:0% +have things about the demand the +capacity the revenues costs and so forth + + align:start position:0% +capacity the revenues costs and so forth + + + align:start position:0% +capacity the revenues costs and so forth +and i have a present value and so forth + + align:start position:0% +and i have a present value and so forth + + + align:start position:0% +and i have a present value and so forth +so i need a model which says + + align:start position:0% +so i need a model which says + + + align:start position:0% +so i need a model which says +if + + align:start position:0% +if + + + align:start position:0% +if +the + + align:start position:0% +the + + + align:start position:0% +the +following happen and you've made these + + align:start position:0% +following happen and you've made these + + + align:start position:0% +following happen and you've made these +design decisions here's what the + + align:start position:0% +design decisions here's what the + + + align:start position:0% +design decisions here's what the +performance is going to be + + align:start position:0% + + + + align:start position:0% + +secondly you need to think about + + align:start position:0% +secondly you need to think about + + + align:start position:0% +secondly you need to think about +which of the most important + + align:start position:0% +which of the most important + + + align:start position:0% +which of the most important +uncertainties + + align:start position:0% +uncertainties + + + align:start position:0% +uncertainties +as uh you could imagine and then those + + align:start position:0% +as uh you could imagine and then those + + + align:start position:0% +as uh you could imagine and then those +who filled out the initial project + + align:start position:0% +who filled out the initial project + + + align:start position:0% +who filled out the initial project +report were + + align:start position:0% +report were + + + align:start position:0% +report were +doing + + align:start position:0% +doing + + + align:start position:0% +doing +you can list them and there are lots and + + align:start position:0% +you can list them and there are lots and + + + align:start position:0% +you can list them and there are lots and +lots of uncertainties all kinds of + + align:start position:0% +lots of uncertainties all kinds of + + + align:start position:0% +lots of uncertainties all kinds of +things can happen + + align:start position:0% +things can happen + + + align:start position:0% +things can happen +the question is what should you really + + align:start position:0% +the question is what should you really + + + align:start position:0% +the question is what should you really +pay attention to + + align:start position:0% +pay attention to + + + align:start position:0% +pay attention to +so you need to think about + + align:start position:0% +so you need to think about + + + align:start position:0% +so you need to think about +which are the + + align:start position:0% +which are the + + + align:start position:0% +which are the +issues the uncertainties that you want + + align:start position:0% +issues the uncertainties that you want + + + align:start position:0% +issues the uncertainties that you want +to focus on not that they all don't + + align:start position:0% +to focus on not that they all don't + + + align:start position:0% +to focus on not that they all don't +exist but some of them are second order + + align:start position:0% +exist but some of them are second order + + + align:start position:0% +exist but some of them are second order +effect so which are the first order + + align:start position:0% +effect so which are the first order + + + align:start position:0% +effect so which are the first order +effects + + align:start position:0% +effects + + + align:start position:0% +effects +one of the ways to do that is to use a + + align:start position:0% +one of the ways to do that is to use a + + + align:start position:0% +one of the ways to do that is to use a +tornado diagram which i will uh + + align:start position:0% +tornado diagram which i will uh + + + align:start position:0% +tornado diagram which i will uh +illustrate here but i'll describe in + + align:start position:0% +illustrate here but i'll describe in + + + align:start position:0% +illustrate here but i'll describe in +more detail later on in the course but + + align:start position:0% +more detail later on in the course but + + + align:start position:0% +more detail later on in the course but +you need to have some way of filtering + + align:start position:0% +you need to have some way of filtering + + + align:start position:0% +you need to have some way of filtering +out + + align:start position:0% +out + + + align:start position:0% +out +the important issues to focus on + + align:start position:0% +the important issues to focus on + + + align:start position:0% +the important issues to focus on +in the garage case it was the level of + + align:start position:0% +in the garage case it was the level of + + + align:start position:0% +in the garage case it was the level of +demand i + + align:start position:0% +demand i + + + align:start position:0% +demand i +sort of didn't talk about the strength + + align:start position:0% +sort of didn't talk about the strength + + + align:start position:0% +sort of didn't talk about the strength +of the concrete or parking registrations + + align:start position:0% +of the concrete or parking registrations + + + align:start position:0% +of the concrete or parking registrations +or things like that but uh focusing on + + align:start position:0% +or things like that but uh focusing on + + + align:start position:0% +or things like that but uh focusing on +the right + + align:start position:0% +the right + + + align:start position:0% +the right +issues + + align:start position:0% +issues + + + align:start position:0% +issues +and i say that in the context that + + align:start position:0% +and i say that in the context that + + + align:start position:0% +and i say that in the context that +here in the from the garage case you can + + align:start position:0% +here in the from the garage case you can + + + align:start position:0% +here in the from the garage case you can +have all kinds of uncertainties that are + + align:start position:0% +have all kinds of uncertainties that are + + + align:start position:0% +have all kinds of uncertainties that are +playing out and each of these will give + + align:start position:0% +playing out and each of these will give + + + align:start position:0% +playing out and each of these will give +you different results at the end so + + align:start position:0% +you different results at the end so + + + align:start position:0% +you different results at the end so +which ones am i really going to focus on + + align:start position:0% +which ones am i really going to focus on + + + align:start position:0% +which ones am i really going to focus on +i don't want to be swamped by everything + + align:start position:0% +i don't want to be swamped by everything + + + align:start position:0% +i don't want to be swamped by everything +else + + align:start position:0% +else + + + align:start position:0% +else +so one way to do it is a tornado diagram + + align:start position:0% +so one way to do it is a tornado diagram + + + align:start position:0% +so one way to do it is a tornado diagram +which the end result is that you have + + align:start position:0% +which the end result is that you have + + + align:start position:0% +which the end result is that you have +various uncertainties this is taken from + + align:start position:0% +various uncertainties this is taken from + + + align:start position:0% +various uncertainties this is taken from +somebody's project some years back + + align:start position:0% +somebody's project some years back + + + align:start position:0% +somebody's project some years back +the demand the revenues operating costs + + align:start position:0% +the demand the revenues operating costs + + + align:start position:0% +the demand the revenues operating costs +et cetera down here + + align:start position:0% +et cetera down here + + + align:start position:0% +et cetera down here +and from the base case that is a the + + align:start position:0% +and from the base case that is a the + + + align:start position:0% +and from the base case that is a the +median case if you want the forecast + + align:start position:0% +median case if you want the forecast + + + align:start position:0% +median case if you want the forecast +case + + align:start position:0% +case + + + align:start position:0% +case +um + + align:start position:0% +um + + + align:start position:0% +um +you have a performance and if the demand + + align:start position:0% +you have a performance and if the demand + + + align:start position:0% +you have a performance and if the demand +went up in one way or down it have this + + align:start position:0% +went up in one way or down it have this + + + align:start position:0% +went up in one way or down it have this +range of effects + + align:start position:0% +range of effects + + + align:start position:0% +range of effects +and it's called a tornado diagram + + align:start position:0% +and it's called a tornado diagram + + + align:start position:0% +and it's called a tornado diagram +because when you look at the sensitivity + + align:start position:0% +because when you look at the sensitivity + + + align:start position:0% +because when you look at the sensitivity +to each of these uncertainties + + align:start position:0% +to each of these uncertainties + + + align:start position:0% +to each of these uncertainties +uh you stack the results so the ones + + align:start position:0% +uh you stack the results so the ones + + + align:start position:0% +uh you stack the results so the ones +which are least incentive at the bottom + + align:start position:0% +which are least incentive at the bottom + + + align:start position:0% +which are least incentive at the bottom +the ones that are most sensitive are at + + align:start position:0% +the ones that are most sensitive are at + + + align:start position:0% +the ones that are most sensitive are at +the top and therefore it has this funnel + + align:start position:0% +the top and therefore it has this funnel + + + align:start position:0% +the top and therefore it has this funnel +shape and that's why it's called a + + align:start position:0% +shape and that's why it's called a + + + align:start position:0% +shape and that's why it's called a +tornado diagram because it is + + align:start position:0% +tornado diagram because it is + + + align:start position:0% +tornado diagram because it is +the way a tornado looks like uh + + align:start position:0% +the way a tornado looks like uh + + + align:start position:0% +the way a tornado looks like uh +prototypically + + align:start position:0% +prototypically + + + align:start position:0% +prototypically +so the the idea is basically you think + + align:start position:0% +so the the idea is basically you think + + + align:start position:0% +so the the idea is basically you think +about + + align:start position:0% +about + + + align:start position:0% +about +how much your uncertainties might vary + + align:start position:0% +how much your uncertainties might vary + + + align:start position:0% +how much your uncertainties might vary +within a standard deviation + + align:start position:0% +within a standard deviation + + + align:start position:0% +within a standard deviation +and or and if it's symmetric or not + + align:start position:0% +and or and if it's symmetric or not + + + align:start position:0% +and or and if it's symmetric or not +symmetric + + align:start position:0% +symmetric + + + align:start position:0% +symmetric +and you run the analysis with those + + align:start position:0% +and you run the analysis with those + + + align:start position:0% +and you run the analysis with those +extremes and you see which are the ones + + align:start position:0% +extremes and you see which are the ones + + + align:start position:0% +extremes and you see which are the ones +that have the most effect + + align:start position:0% +that have the most effect + + + align:start position:0% +that have the most effect +and + + align:start position:0% +and + + + align:start position:0% +and +in this case for example the demand is + + align:start position:0% +in this case for example the demand is + + + align:start position:0% +in this case for example the demand is +the most important one in this uh + + align:start position:0% +the most important one in this uh + + + align:start position:0% +the most important one in this uh +particular case and so this you can + + align:start position:0% +particular case and so this you can + + + align:start position:0% +particular case and so this you can +focus on the revenue maybe next but the + + align:start position:0% +focus on the revenue maybe next but the + + + align:start position:0% +focus on the revenue maybe next but the +other ones don't make that much + + align:start position:0% +other ones don't make that much + + + align:start position:0% +other ones don't make that much +difference so that at least for the + + align:start position:0% +difference so that at least for the + + + align:start position:0% +difference so that at least for the +beginning we focus on the top ones and + + align:start position:0% +beginning we focus on the top ones and + + + align:start position:0% +beginning we focus on the top ones and +proceed ahead so at some level once you + + align:start position:0% +proceed ahead so at some level once you + + + align:start position:0% +proceed ahead so at some level once you +consider that things can be uncertain + + align:start position:0% +consider that things can be uncertain + + + align:start position:0% +consider that things can be uncertain +you may be swamped by all the + + align:start position:0% +you may be swamped by all the + + + align:start position:0% +you may be swamped by all the +possibilities all the things that could + + align:start position:0% +possibilities all the things that could + + + align:start position:0% +possibilities all the things that could +happen and you don't want to do that you + + align:start position:0% +happen and you don't want to do that you + + + align:start position:0% +happen and you don't want to do that you +want to have some way of focusing your + + align:start position:0% +want to have some way of focusing your + + + align:start position:0% +want to have some way of focusing your +attention on the things that matter and + + align:start position:0% +attention on the things that matter and + + + align:start position:0% +attention on the things that matter and +a tornado diagram is one way to do it + + align:start position:0% + + + + align:start position:0% + +you may also want to think about how + + align:start position:0% +you may also want to think about how + + + align:start position:0% +you may also want to think about how +things may change over time + + align:start position:0% +things may change over time + + + align:start position:0% +things may change over time +this was the + + align:start position:0% +this was the + + + align:start position:0% +this was the +basic forecast that we use for the + + align:start position:0% +basic forecast that we use for the + + + align:start position:0% +basic forecast that we use for the +garage case i'm not pretending it's the + + align:start position:0% +garage case i'm not pretending it's the + + + align:start position:0% +garage case i'm not pretending it's the +right one but i'm simply saying it's an + + align:start position:0% +right one but i'm simply saying it's an + + + align:start position:0% +right one but i'm simply saying it's an +illustration of the kind of issue that + + align:start position:0% +illustration of the kind of issue that + + + align:start position:0% +illustration of the kind of issue that +you have + + align:start position:0% +you have + + + align:start position:0% +you have +so you start at a particular level and + + align:start position:0% +so you start at a particular level and + + + align:start position:0% +so you start at a particular level and +you think it might grow particularly + + align:start position:0% +you think it might grow particularly + + + align:start position:0% +you think it might grow particularly +quickly at that time and it might level + + align:start position:0% +quickly at that time and it might level + + + align:start position:0% +quickly at that time and it might level +off + + align:start position:0% +off + + + align:start position:0% +off +and that one of the forecasts that we + + align:start position:0% +and that one of the forecasts that we + + + align:start position:0% +and that one of the forecasts that we +were looking at today which was a uh + + align:start position:0% +were looking at today which was a uh + + + align:start position:0% +were looking at today which was a uh +renewable energy uh by the energy + + align:start position:0% +renewable energy uh by the energy + + + align:start position:0% +renewable energy uh by the energy +production by renewables you saw that + + align:start position:0% +production by renewables you saw that + + + align:start position:0% +production by renewables you saw that +many forecasts had a growth and then + + align:start position:0% +many forecasts had a growth and then + + + align:start position:0% +many forecasts had a growth and then +leveled off so thinking that this may be + + align:start position:0% +leveled off so thinking that this may be + + + align:start position:0% +leveled off so thinking that this may be +appropriate for your problem uh is + + align:start position:0% +appropriate for your problem uh is + + + align:start position:0% +appropriate for your problem uh is +something you will do that is your + + align:start position:0% +something you will do that is your + + + align:start position:0% +something you will do that is your +forecast may have a certain uncertainty + + align:start position:0% +forecast may have a certain uncertainty + + + align:start position:0% +forecast may have a certain uncertainty +all along but it may be around a + + align:start position:0% +all along but it may be around a + + + align:start position:0% +all along but it may be around a +particular pattern of growth which might + + align:start position:0% +particular pattern of growth which might + + + align:start position:0% +particular pattern of growth which might +be an s-shaped pattern it might be + + align:start position:0% +be an s-shaped pattern it might be + + + align:start position:0% +be an s-shaped pattern it might be +this shape it might be a straight + + align:start position:0% +this shape it might be a straight + + + align:start position:0% +this shape it might be a straight +shape it might be exponential but you + + align:start position:0% +shape it might be exponential but you + + + align:start position:0% +shape it might be exponential but you +want to think about a distribution + + align:start position:0% +want to think about a distribution + + + align:start position:0% +want to think about a distribution +aspect over time not just at any one + + align:start position:0% +aspect over time not just at any one + + + align:start position:0% +aspect over time not just at any one +time \ No newline at end of file diff --git a/jwfeVqhqEB8.txt b/jwfeVqhqEB8.txt new file mode 100644 index 0000000000000000000000000000000000000000..7c2820a2336c7e9d6957ded36f69bb0dddb97e82 --- /dev/null +++ b/jwfeVqhqEB8.txt @@ -0,0 +1,440 @@ +If you put water in the freezer, you'll end +up with ice. If you leave ice on your countertop, + +you'll end up with liquid water. You've almost +certainly seen these phase changes in your + +everyday experience. But there's more to freezing +and melting than meets the eye, and we can + +use these seemingly simple phenomena to make +buildings significantly more energy efficient. + +In this video, we'll explain the concept of +"latent heat" and see how it can dramatically + +reduce heating and cooling costs in homes +and skyscrapers alike. + +This video is part of the Conservation video +series. + +In order to analyze or modify a system, it +is important to understand how the laws of + +conservation place constraints on that system. + +Hi. My name is Stephen Ray and I am a graduate +student in the Department of Mechanical Engineering + +at MIT. My research in the Building Technology +Lab under the guidance of Professor Leon Glicksman + +focuses on energy efficient buildings. + +In order to understand the topic of this video, +you should be familiar with the Law of Conservation + +of Energy. You should also be familiar with +the effects of intermolecular forces on phase + +transitions. + +After watching this video, you should be able +to describe the energy transformations that + +occur during a phase change and apply the +law of conservation of energy to phase changes. + +Let's start with a demonstration. + +Here we have a container of water to which +we are adding table salt. + +Quite a bit of table salt, actually. + +Let's stir that up. + +Next, we are going to crush up some ice to +add to the salt water. + +Our goal is to lower the temperature of the +ice bath. + +Let's add some more salt. + +Freezing point depression, yeah! + +Alright, minus 8 degrees Celcius. That's pretty +good. + +Let's place a smaller container of liquid +water into this ice bath. We've added green + +food coloring to the water so that it is easier +for you to see. + +After a few minutes, we'll insert a thermometer +and watch the temperature drop as the water + +is cooled by the ice bath. + +The temperature reads about -5 degrees Celsius. +The green water is still a liquid even though + +the temperature is below the normal freezing +point of water. This is called supercooling. + +In the next step of this demo, we are going +to add a couple of small pieces of ice to + +the green water. The supercooled water will +crystallize rapidly with the addition of the + +ice. + +When this happens, what do you predict will +happen to the temperature on the thermometer? + +Will it increase, decrease, or stay the same? + +What reasoning supports your prediction? Pause +the video here to discuss your ideas with + +the person beside you, then continue playing +the video to see what happens. + +Okay, ready to see what happens? Be sure to +keep your eye on the digital display. + +Now we'll drop a couple of small pieces of +ice into the container of green water. + +Watch what's happening. + +The green water froze. There is still a little +bit of liquid, but we can turn the container + +upside down and you can see that the ice remains +inside. + +So, when the liquid froze, what happened to +the temperature? + +The temperature went up! Is this what you +predicted? How can we explain what happened? + +Well, let's think about what happens at a +molecular level when water changes phase from + +a liquid to a solid. In the liquid state, +water molecules are moving around a lot. As + +it gets colder, the water molecules slow down. + +Generally speaking, as the water cools and +solidifies, there is an increase in hydrogen + +bonding, the dominant intermolecular force +amongst the water molecules. + +With this hint, can you now explain why we +observed a temperature increase when the water + +froze? Pause the video, take a moment to think +about it on your own and then discuss your + +idea with a classmate. Then, continue playing +the video for an explanation. + +As we said before, when water transitions +from liquid to solid, there is an increase + +in the number of hydrogen bonds that are formed +between water molecules. Does bond formation + +release energy or require energy? + +Bond formation releases energy. + +So then, is the process of ice forming exothermic +or endothermic? + +Ice formation is exothermic. + +If we were to do an energy balance on the +system and the surroundings, we would see + +that the energy that was released by the water +freezing is equivalent to the thermal energy + +that caused the temperature to increase. This +is the Law of Conservation of Energy. + +Generally speaking, when a substance transitions +between phases, intermolecular forces between + +neighboring molecules are either formed or +broken. When a substance transitions from + +a liquid to a solid, intermolecular forces, +or bonds, are formed and energy is released + +to the surroundings. This is called the latent +heat of fusion. + +Going in the other direction, when a substance +transitions from a solid to a liquid, energy + +is required to overcome intermolecular forces, +so this is an endothermic process. Energy + +is absorbed from the surroundings. This is +called the latent heat of melting. + +The latent heat of melting is equivalent in +magnitude to the latent heat of fusion, but + +opposite in sign. + +This phenomenon of latent heat is used in +a variety of ways to heat and cool buildings. + +Using melting ice to absorb thermal energy +from the surroundings saves some buildings + +thousands of dollars a year in cooling costs. + +Consider a large office building during the +middle of a hot summer day. In order to keep + +the building comfortable, the air conditioning +is running at full power, requiring a lot + +of electricity from the utility company. The +utility companies can't easily shut down their + +power plants, so nearly the same amount of +electricity is produced during the night as + +is during the day. However, nighttime demand +for electricity is very low, so utility companies + +sell this electricity at a lower price. This +is common practice by utility companies across + +the U.S. + +Engineers have thought of a way to buy the +electricity during the night when it is very + +cheap, but use it during the day when they +need to run the air conditioning. This strategy + +is called peak load shifting. Think about +what you have learned so far. There are a + +variety of ways this can be done. How do you +think they do this? Pause the video here, + +take a moment to think about it, and discuss +your idea with the person next to you. Continue + +playing the video to hear about one way they +do this. + +One way we can decrease the amount of electricity +needed in the daytime to cool a building is + +to use the energy storage capacity of ice, +or its latent heat of melting. + +Large tanks, such as these in the basement +of the Bank of America Tower in New York, + +store water that is frozen over night using +cheap electricity. During the day, the ice + +melts and absorbs energy from the cooling +fluid running through the building's air conditioning + +system. Each of the tanks in the Bank of America +building holds approximately 1600 gallons + +of water which translates to roughly 570 kilowatt +hours of cooling capacity. Bank of America + +reports that these ice tanks supply 25% of +their cooling energy annually. + +The desire to harness latent heat has led +to the development of a class of materials + +called phase change materials. These materials +have been specifically designed to change + +phase at desirable temperatures so that they +can store and release energy in a way that + +is useful to consumers. This slide shows some +examples of these materials. The materials + +on this slide fall into three classes of phase +change materials: inorganic salt hydrates, + +paraffinic hydrocarbons, and organic fatty +acids. + +Some ordinary building materials such as concrete, +dry wall, or insulation have been specially + +engineered over the past 50 years to contain +microscopic pellets of phase change materials. + +Cellulose insulation, shown here, is commonly +used to insulate attics and walls. Researchers + +at the Oak Ridge National Laboratories in +the United States have impregnated small paraffin + +pellets in this common type of insulation +to increase its performance. + +Because these pellets are microscopic, the +phase change insulation looks exactly like + +the ordinary insulation to our naked eye. +However, under a Scanning Electron Microscopic, + +the clusters of paraffinic pellets are easy +to spot. + +Now lets look at the measured performance +of a similar type of phase change insulation + +that is installed in a typical residential +roof. The chart here shows the heat transfer + +into a house on the vertical axis and time +on the horizontal axis. The two large black + +peaks, which occur during two consecutive +summer days, correspond to the large amount + +of heat transfer into a home that a conventional +roof allows. The smaller green peaks show + +how changing the roof surface material and +venting the attic significantly help lower + +the heat transfer into a home by approximately +70%. This reduction in heat transfer leads + +to less energy required for cooling the home. +The purple curve shows that if phase change + +insulation is used in addition to these roof +modifications, we can reduce the required + +cooling energy by 90%! + +How does phase change insulation help save +energy? Pause the video, take a moment to + +think about it, and share your thoughts with +a classmate. + +Consider two homes with and without PCM roof +insulation. Both homes are exposed to the + +same amount of solar energy from the sun. +Although not all of that energy enters the + +home without PCM insulation, a significant +portion is transferred through the roof into + +the house. The house with PCM insulation reduces +this amount because some of the energy that + +would otherwise enter the house is used to +melt the phase change material in the roof. + +In order for this effect to occur each day, +the phase change material must solidify every + +night before it can melt again the next day. + +Let's take a look at this chart of example +phase change materials again. What phase change + +material would you use in a home or building +in Singapore? Why? What additional information + +might you need to know to help make your decision? +Pause the video here and discuss your choice + +with the person beside you. + +On average, year-round temperatures in Singapore +hover between 23 and 32 degrees Celcius. This + +is important when making our decision. Some +of you may have selected the calcium chloride + +hydrate as a candidate phase change material +because its melting temperature falls within + +the range of daytime high temperatures in +Singapore. You may have selected octadecane + +for a similar reason. If you eliminated paraffin +wax and palmitic acid, it was probably because + +their melting points are so much higher than +the highest outdoor temperatures reached in + +the day. However, these phase change materials +could be used on a conventional dark-colored + +roof where temperatures can exceed 70 C because +of all the energy absorbed from the sun. Caprylic + +acid, on the other hand, has such a low melting +temperature, that few, if any, building components + +would ever drop below this temperature. + +So, let's go back to calcium chloride hydrate +and octadecane. Both would melt and solidify + +within the temperature range of the environment, +but octadecane has a higher heat of fusion, + +which leads to greater potential energy savings. +While it is beyond the scope of this video, + +we also need to think about the heat transfer +properties of the other building materials + +used in the roof and the cost and stability +of the phase change materials. + +Today, you learned about the concept of latent +heat and how the energy transformations that + +occur during a phase change are a consequence +of the law of conservation of energy. You + +also saw how engineers have used the concept +of latent heat to design phase change materials + +that can allow us to cool and heat homes more +efficiently. The incorporation of phase change + +materials in building materials is still an +active area of research. There are still engineering + +challenges to address, perhaps by you, in +order to make these technologies cost-effective + +and more widely used. \ No newline at end of file diff --git a/mc1y8m9-hOM.txt b/mc1y8m9-hOM.txt new file mode 100644 index 0000000000000000000000000000000000000000..65045aa06604bbbc36fe3d031484522440db0f9c --- /dev/null +++ b/mc1y8m9-hOM.txt @@ -0,0 +1,13523 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a creative common license your support + + align:start position:0% +a creative common license your support + + + align:start position:0% +a creative common license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +to view additional materials from + + align:start position:0% +to view additional materials from + + + align:start position:0% +to view additional materials from +hundreds of MIT courses visit MIT + + align:start position:0% +hundreds of MIT courses visit MIT + + + align:start position:0% +hundreds of MIT courses visit MIT +opencourseware at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu we're talking about + + align:start position:0% +ocw.mit.edu we're talking about + + + align:start position:0% +ocw.mit.edu we're talking about +um generalized linear models and in + + align:start position:0% +um generalized linear models and in + + + align:start position:0% +um generalized linear models and in +generalized linear models we generalize + + align:start position:0% +generalized linear models we generalize + + + align:start position:0% +generalized linear models we generalize +uh linear models in two ways uh the + + align:start position:0% +uh linear models in two ways uh the + + + align:start position:0% +uh linear models in two ways uh the +first one is to allow for different + + align:start position:0% +first one is to allow for different + + + align:start position:0% +first one is to allow for different +distribution for the response variables + + align:start position:0% +distribution for the response variables + + + align:start position:0% +distribution for the response variables +and the distributions that we wanted was + + align:start position:0% +and the distributions that we wanted was + + + align:start position:0% +and the distributions that we wanted was +uh the exponential + + align:start position:0% + + + + align:start position:0% + +family and uh this is a family that can + + align:start position:0% +family and uh this is a family that can + + + align:start position:0% +family and uh this is a family that can +be generalized over uh random variables + + align:start position:0% +be generalized over uh random variables + + + align:start position:0% +be generalized over uh random variables +that are defined on say RQ in general + + align:start position:0% +that are defined on say RQ in general + + + align:start position:0% +that are defined on say RQ in general +with parameters in RK but we're going to + + align:start position:0% +with parameters in RK but we're going to + + + align:start position:0% +with parameters in RK but we're going to +focus in a very specific case where uh + + align:start position:0% +focus in a very specific case where uh + + + align:start position:0% +focus in a very specific case where uh +this is when R is equal uh Y is a real + + align:start position:0% +this is when R is equal uh Y is a real + + + align:start position:0% +this is when R is equal uh Y is a real +valued resp resp variable which is the + + align:start position:0% +valued resp resp variable which is the + + + align:start position:0% +valued resp resp variable which is the +one you're used to when you're doing uh + + align:start position:0% +one you're used to when you're doing uh + + + align:start position:0% +one you're used to when you're doing uh +linear regression and the parameter + + align:start position:0% +linear regression and the parameter + + + align:start position:0% +linear regression and the parameter +Theta also uh lives in R and so we're + + align:start position:0% +Theta also uh lives in R and so we're + + + align:start position:0% +Theta also uh lives in R and so we're +going to talk about the canonical case + + align:start position:0% +going to talk about the canonical case + + + align:start position:0% +going to talk about the canonical case +so that's the + + align:start position:0% +so that's the + + + align:start position:0% +so that's the +canonical uh uh exponential family where + + align:start position:0% +canonical uh uh exponential family where + + + align:start position:0% +canonical uh uh exponential family where +you have a density F Theta of X which is + + align:start position:0% +you have a density F Theta of X which is + + + align:start position:0% +you have a density F Theta of X which is +of the form + + align:start position:0% +of the form + + + align:start position:0% +of the form +exponential uh minus uh sorry + + align:start position:0% +exponential uh minus uh sorry + + + align:start position:0% +exponential uh minus uh sorry +exponential plus and then we have Y + + align:start position:0% +exponential plus and then we have Y + + + align:start position:0% +exponential plus and then we have Y +which interact with Theta only by taking + + align:start position:0% +which interact with Theta only by taking + + + align:start position:0% +which interact with Theta only by taking +a product then there's a term that + + align:start position:0% +a product then there's a term that + + + align:start position:0% +a product then there's a term that +depends only on Theta uh some dispersion + + align:start position:0% +depends only on Theta uh some dispersion + + + align:start position:0% +depends only on Theta uh some dispersion +parameter fi and then we have some + + align:start position:0% +parameter fi and then we have some + + + align:start position:0% +parameter fi and then we have some +normalization Factor let's call it C of + + align:start position:0% +normalization Factor let's call it C of + + + align:start position:0% +normalization Factor let's call it C of +Y + + align:start position:0% +Y + + + align:start position:0% +Y +uh five so it only depends so I really + + align:start position:0% +uh five so it only depends so I really + + + align:start position:0% +uh five so it only depends so I really +should not matter too much so it's a c + + align:start position:0% +should not matter too much so it's a c + + + align:start position:0% +should not matter too much so it's a c +of yfi and that's really just a + + align:start position:0% +of yfi and that's really just a + + + align:start position:0% +of yfi and that's really just a +normalization factor and here we said + + align:start position:0% +normalization factor and here we said + + + align:start position:0% +normalization factor and here we said +that we're going to assume that fi is + + align:start position:0% + + + + align:start position:0% + +known okay I just I have no idea what I + + align:start position:0% +known okay I just I have no idea what I + + + align:start position:0% +known okay I just I have no idea what I +write I don't know if you guys canite + + align:start position:0% +write I don't know if you guys canite + + + align:start position:0% +write I don't know if you guys canite +read I don't know what chalk has been + + align:start position:0% +read I don't know what chalk has been + + + align:start position:0% +read I don't know what chalk has been +used today but I just can't see it um + + align:start position:0% +used today but I just can't see it um + + + align:start position:0% +used today but I just can't see it um +that's not my fault um all right so + + align:start position:0% +that's not my fault um all right so + + + align:start position:0% +that's not my fault um all right so +we're going to assume that fi is known + + align:start position:0% +we're going to assume that fi is known + + + align:start position:0% +we're going to assume that fi is known +and so we saw that you know several + + align:start position:0% +and so we saw that you know several + + + align:start position:0% +and so we saw that you know several +distributions that we know well + + align:start position:0% +distributions that we know well + + + align:start position:0% +distributions that we know well +including the gaon for example belong to + + align:start position:0% +including the gaon for example belong to + + + align:start position:0% +including the gaon for example belong to +this family and there's other ones such + + align:start position:0% +this family and there's other ones such + + + align:start position:0% +this family and there's other ones such +as + + align:start position:0% +as + + + align:start position:0% +as +P sorry p and Burnley so if the pmf has + + align:start position:0% +P sorry p and Burnley so if the pmf has + + + align:start position:0% +P sorry p and Burnley so if the pmf has +this form if you have a discrete random + + align:start position:0% +this form if you have a discrete random + + + align:start position:0% +this form if you have a discrete random +variable this is also valid and uh the + + align:start position:0% +variable this is also valid and uh the + + + align:start position:0% +variable this is also valid and uh the +reason why we introduced this family is + + align:start position:0% +reason why we introduced this family is + + + align:start position:0% +reason why we introduced this family is +because there're going to be some + + align:start position:0% +because there're going to be some + + + align:start position:0% +because there're going to be some +properties so we know that this thing + + align:start position:0% +properties so we know that this thing + + + align:start position:0% +properties so we know that this thing +here this function B of theta is + + align:start position:0% +here this function B of theta is + + + align:start position:0% +here this function B of theta is +essentially what completely + + align:start position:0% +essentially what completely + + + align:start position:0% +essentially what completely +characterizes your distribution right so + + align:start position:0% +characterizes your distribution right so + + + align:start position:0% +characterizes your distribution right so +if f is fixed we know that the + + align:start position:0% +if f is fixed we know that the + + + align:start position:0% +if f is fixed we know that the +interaction is the form this form and + + align:start position:0% +interaction is the form this form and + + + align:start position:0% +interaction is the form this form and +this really just comes from the fact + + align:start position:0% +this really just comes from the fact + + + align:start position:0% +this really just comes from the fact +that we want the function to integrate + + align:start position:0% +that we want the function to integrate + + + align:start position:0% +that we want the function to integrate +to one so this B here in the canonical + + align:start position:0% +to one so this B here in the canonical + + + align:start position:0% +to one so this B here in the canonical +form encodes everything we want to know + + align:start position:0% +form encodes everything we want to know + + + align:start position:0% +form encodes everything we want to know +if I tell you what B of theta is and of + + align:start position:0% +if I tell you what B of theta is and of + + + align:start position:0% +if I tell you what B of theta is and of +course I tell you what f is but let's + + align:start position:0% +course I tell you what f is but let's + + + align:start position:0% +course I tell you what f is but let's +say for a second that five is equal to + + align:start position:0% +say for a second that five is equal to + + + align:start position:0% +say for a second that five is equal to +one if I tell you this B of theta you + + align:start position:0% +one if I tell you this B of theta you + + + align:start position:0% +one if I tell you this B of theta you +know exactly what distribution I'm + + align:start position:0% +know exactly what distribution I'm + + + align:start position:0% +know exactly what distribution I'm +talking about + + align:start position:0% +talking about + + + align:start position:0% +talking about +so it should encode everything that's + + align:start position:0% +so it should encode everything that's + + + align:start position:0% +so it should encode everything that's +you know specific to this distribution + + align:start position:0% +you know specific to this distribution + + + align:start position:0% +you know specific to this distribution +such as mean variance all the moments + + align:start position:0% +such as mean variance all the moments + + + align:start position:0% +such as mean variance all the moments +that you would want and uh uh we'll see + + align:start position:0% +that you would want and uh uh we'll see + + + align:start position:0% +that you would want and uh uh we'll see +how we can compute from this thing uh uh + + align:start position:0% +how we can compute from this thing uh uh + + + align:start position:0% +how we can compute from this thing uh uh +the mean and the variance for example So + + align:start position:0% +the mean and the variance for example So + + + align:start position:0% +the mean and the variance for example So +today we're going to talk about + + align:start position:0% +today we're going to talk about + + + align:start position:0% +today we're going to talk about +likelihood and we're going to start with + + align:start position:0% +likelihood and we're going to start with + + + align:start position:0% +likelihood and we're going to start with +the likelihood function or the log + + align:start position:0% +the likelihood function or the log + + + align:start position:0% +the likelihood function or the log +likelihood for one observation from this + + align:start position:0% +likelihood for one observation from this + + + align:start position:0% +likelihood for one observation from this +we're going to do some computations and + + align:start position:0% +we're going to do some computations and + + + align:start position:0% +we're going to do some computations and +then we'll move on to the actual log + + align:start position:0% +then we'll move on to the actual log + + + align:start position:0% +then we'll move on to the actual log +likelihood based on N independent + + align:start position:0% +likelihood based on N independent + + + align:start position:0% +likelihood based on N independent +observations and here as we will see the + + align:start position:0% +observations and here as we will see the + + + align:start position:0% +observations and here as we will see the +observations are not going to be + + align:start position:0% +observations are not going to be + + + align:start position:0% +observations are not going to be +identically distributed because we're + + align:start position:0% +identically distributed because we're + + + align:start position:0% +identically distributed because we're +going to want each of them I mean + + align:start position:0% +going to want each of them I mean + + + align:start position:0% +going to want each of them I mean +conditionally on X to have a different + + align:start position:0% +conditionally on X to have a different + + + align:start position:0% +conditionally on X to have a different +to be a different function of X okay to + + align:start position:0% +to be a different function of X okay to + + + align:start position:0% +to be a different function of X okay to +where Theta is just a different function + + align:start position:0% +where Theta is just a different function + + + align:start position:0% +where Theta is just a different function +of X for each of the observations right + + align:start position:0% +of X for each of the observations right + + + align:start position:0% +of X for each of the observations right +so remember the log + + align:start position:0% + + + + align:start position:0% + +likelihood and this is for one + + align:start position:0% +likelihood and this is for one + + + align:start position:0% +likelihood and this is for one +observation is just the log of the + + align:start position:0% +observation is just the log of the + + + align:start position:0% +observation is just the log of the +density + + align:start position:0% + + + + align:start position:0% + +right and uh uh we have this identity + + align:start position:0% +right and uh uh we have this identity + + + align:start position:0% +right and uh uh we have this identity +that I mentioned uh uh at the end of the + + align:start position:0% +that I mentioned uh uh at the end of the + + + align:start position:0% +that I mentioned uh uh at the end of the +class on Tuesday and this identity is + + align:start position:0% +class on Tuesday and this identity is + + + align:start position:0% +class on Tuesday and this identity is +just that the expectation of the + + align:start position:0% +just that the expectation of the + + + align:start position:0% +just that the expectation of the +derivative of this guy with respect to + + align:start position:0% +derivative of this guy with respect to + + + align:start position:0% +derivative of this guy with respect to +Theta is equal to zero so let's see why + + align:start position:0% +Theta is equal to zero so let's see why + + + align:start position:0% +Theta is equal to zero so let's see why +so if I take the derivative with respect + + align:start position:0% +so if I take the derivative with respect + + + align:start position:0% +so if I take the derivative with respect +to Theta of log F Theta of X what I get + + align:start position:0% +to Theta of log F Theta of X what I get + + + align:start position:0% +to Theta of log F Theta of X what I get +is the derivative with respect to + + align:start position:0% +is the derivative with respect to + + + align:start position:0% +is the derivative with respect to +Theta of f Theta of x divided by F Theta + + align:start position:0% +Theta of f Theta of x divided by F Theta + + + align:start position:0% +Theta of f Theta of x divided by F Theta +of + + align:start position:0% +of + + + align:start position:0% +of +X right now if I take the expectation of + + align:start position:0% +X right now if I take the expectation of + + + align:start position:0% +X right now if I take the expectation of +this guy + + align:start position:0% +this guy + + + align:start position:0% +this guy +with respect to this steta as + + align:start position:0% + + + + align:start position:0% + +well what I get is that this thing what + + align:start position:0% +well what I get is that this thing what + + + align:start position:0% +well what I get is that this thing what +is the expectation well it's just the + + align:start position:0% +is the expectation well it's just the + + + align:start position:0% +is the expectation well it's just the +integral against F Theta or if I'm in a + + align:start position:0% +integral against F Theta or if I'm in a + + + align:start position:0% +integral against F Theta or if I'm in a +discrete case I just have the sum + + align:start position:0% +discrete case I just have the sum + + + align:start position:0% +discrete case I just have the sum +against F Theta right if it's a pmf just + + align:start position:0% +against F Theta right if it's a pmf just + + + align:start position:0% +against F Theta right if it's a pmf just +the distribu the definition of right the + + align:start position:0% +the distribu the definition of right the + + + align:start position:0% +the distribu the definition of right the +expectation of X is either the integral + + align:start position:0% +expectation of X is either the integral + + + align:start position:0% +expectation of X is either the integral +well let's say of H of X is the integral + + align:start position:0% +well let's say of H of X is the integral + + + align:start position:0% +well let's say of H of X is the integral +of H ofx F Theta of x if this is + + align:start position:0% +of H ofx F Theta of x if this is + + + align:start position:0% +of H ofx F Theta of x if this is +discrete or it's just the sum of h ofx f + + align:start position:0% +discrete or it's just the sum of h ofx f + + + align:start position:0% +discrete or it's just the sum of h ofx f +Theta of + + align:start position:0% +Theta of + + + align:start position:0% +Theta of +x if x is discret uh so if it's + + align:start position:0% +x if x is discret uh so if it's + + + align:start position:0% +x if x is discret uh so if it's +continuous you put this uh you know + + align:start position:0% +continuous you put this uh you know + + + align:start position:0% +continuous you put this uh you know +sweet soft sum and if it's uh put the + + align:start position:0% +sweet soft sum and if it's uh put the + + + align:start position:0% +sweet soft sum and if it's uh put the +this guy it's the same thing right so + + align:start position:0% +this guy it's the same thing right so + + + align:start position:0% +this guy it's the same thing right so +I'm just going to illustrate the case + + align:start position:0% +I'm just going to illustrate the case + + + align:start position:0% +I'm just going to illustrate the case +when it's continuous so this is what + + align:start position:0% +when it's continuous so this is what + + + align:start position:0% +when it's continuous so this is what +well this is the integral of partial + + align:start position:0% +well this is the integral of partial + + + align:start position:0% +well this is the integral of partial +derivative with respect to Theta of f + + align:start position:0% +derivative with respect to Theta of f + + + align:start position:0% +derivative with respect to Theta of f +Theta of x / f Theta of X time F Theta + + align:start position:0% +Theta of x / f Theta of X time F Theta + + + align:start position:0% +Theta of x / f Theta of X time F Theta +of + + align:start position:0% + + + + align:start position:0% + +X DX and now this F Theta is cancel so + + align:start position:0% +X DX and now this F Theta is cancel so + + + align:start position:0% +X DX and now this F Theta is cancel so +I'm actually left with the integral of + + align:start position:0% +I'm actually left with the integral of + + + align:start position:0% +I'm actually left with the integral of +the derivative which I'm going to write + + align:start position:0% +the derivative which I'm going to write + + + align:start position:0% +the derivative which I'm going to write +as the derivative of the + + align:start position:0% + + + + align:start position:0% + +integral but F Theta + + align:start position:0% +integral but F Theta + + + align:start position:0% +integral but F Theta +being being a + + align:start position:0% +being being a + + + align:start position:0% +being being a +um uh sorry F Theta being a density for + + align:start position:0% +um uh sorry F Theta being a density for + + + align:start position:0% +um uh sorry F Theta being a density for +any value of theta that I can take this + + align:start position:0% +any value of theta that I can take this + + + align:start position:0% +any value of theta that I can take this +is the function as a function of theta + + align:start position:0% +is the function as a function of theta + + + align:start position:0% +is the function as a function of theta +well actually as a as a function of + + align:start position:0% +well actually as a as a function of + + + align:start position:0% +well actually as a as a function of +theta this function is constantly equal + + align:start position:0% +theta this function is constantly equal + + + align:start position:0% +theta this function is constantly equal +to + + align:start position:0% +to + + + align:start position:0% +to +one right for any Theta I take it takes + + align:start position:0% +one right for any Theta I take it takes + + + align:start position:0% +one right for any Theta I take it takes +value one so this is constantly equal to + + align:start position:0% +value one so this is constantly equal to + + + align:start position:0% +value one so this is constantly equal to +one I put three bars to say that for any + + align:start position:0% +one I put three bars to say that for any + + + align:start position:0% +one I put three bars to say that for any +value of theta this is one which + + align:start position:0% +value of theta this is one which + + + align:start position:0% +value of theta this is one which +actually tells me that the derivative is + + align:start position:0% +actually tells me that the derivative is + + + align:start position:0% +actually tells me that the derivative is +equal to + + align:start position:0% +equal to + + + align:start position:0% +equal to +zero okay yes + + align:start position:0% + + + + align:start position:0% + +that the that's the definition of the + + align:start position:0% +that the that's the definition of the + + + align:start position:0% +that the that's the definition of the +expectation oh sorry uh no that's just + + align:start position:0% +expectation oh sorry uh no that's just + + + align:start position:0% +expectation oh sorry uh no that's just +the the definition of the derivative of + + align:start position:0% +the the definition of the derivative of + + + align:start position:0% +the the definition of the derivative of +a log of a + + align:start position:0% + + + + align:start position:0% + +function log of f Prime is frime over F + + align:start position:0% +function log of f Prime is frime over F + + + align:start position:0% +function log of f Prime is frime over F +right that's a log + + align:start position:0% +right that's a log + + + align:start position:0% +right that's a log +yeah just by elimination + + align:start position:0% + + + + align:start position:0% + +I'm + + align:start position:0% +I'm + + + align:start position:0% +I'm +sorry yeah and that and you do good + + align:start position:0% +sorry yeah and that and you do good + + + align:start position:0% +sorry yeah and that and you do good +because that's probably how my mind's + + align:start position:0% +because that's probably how my mind's + + + align:start position:0% +because that's probably how my mind's +processes and so I'm like yeah L here's + + align:start position:0% +processes and so I'm like yeah L here's + + + align:start position:0% +processes and so I'm like yeah L here's +enough + + align:start position:0% +enough + + + align:start position:0% +enough +information + + align:start position:0% +information + + + align:start position:0% +information +um okay everybody's good with this so + + align:start position:0% +um okay everybody's good with this so + + + align:start position:0% +um okay everybody's good with this so +you know that was convenient so it just + + align:start position:0% +you know that was convenient so it just + + + align:start position:0% +you know that was convenient so it just +said that the expectation of the + + align:start position:0% +said that the expectation of the + + + align:start position:0% +said that the expectation of the +derivative of the log likelihood is + + align:start position:0% +derivative of the log likelihood is + + + align:start position:0% +derivative of the log likelihood is +equal to zero that's going to be our + + align:start position:0% +equal to zero that's going to be our + + + align:start position:0% +equal to zero that's going to be our +first identity let's move move on to the + + align:start position:0% +first identity let's move move on to the + + + align:start position:0% +first identity let's move move on to the +second identity using exactly the same + + align:start position:0% +second identity using exactly the same + + + align:start position:0% +second identity using exactly the same +trick which is let's hope that at some + + align:start position:0% +trick which is let's hope that at some + + + align:start position:0% +trick which is let's hope that at some +point we have the integral of this + + align:start position:0% +point we have the integral of this + + + align:start position:0% +point we have the integral of this +function that's constantly equal to one + + align:start position:0% +function that's constantly equal to one + + + align:start position:0% +function that's constantly equal to one +as a function of theta and then should + + align:start position:0% +as a function of theta and then should + + + align:start position:0% +as a function of theta and then should +show that use the fact that its + + align:start position:0% +show that use the fact that its + + + align:start position:0% +show that use the fact that its +derivative is equal to zero so if I + + align:start position:0% +derivative is equal to zero so if I + + + align:start position:0% +derivative is equal to zero so if I +start taking the second derivative of + + align:start position:0% +start taking the second derivative of + + + align:start position:0% +start taking the second derivative of +the + + align:start position:0% + + + + align:start position:0% + +log uh of f of + + align:start position:0% +log uh of f of + + + align:start position:0% +log uh of f of +theta so what is this well it's the + + align:start position:0% +theta so what is this well it's the + + + align:start position:0% +theta so what is this well it's the +second derivative of it's the the + + align:start position:0% +second derivative of it's the the + + + align:start position:0% +second derivative of it's the the +derivative of this guy here so I'm going + + align:start position:0% +derivative of this guy here so I'm going + + + align:start position:0% +derivative of this guy here so I'm going +to go straight to it so it's second + + align:start position:0% + + + + align:start position:0% + +derivative of f Theta of X time F Theta + + align:start position:0% +derivative of f Theta of X time F Theta + + + align:start position:0% +derivative of f Theta of X time F Theta +of + + align:start position:0% + + + + align:start position:0% + +x + + align:start position:0% +x + + + align:start position:0% +x +minus second derivative first derivative + + align:start position:0% +minus second derivative first derivative + + + align:start position:0% +minus second derivative first derivative +of f Theta of + + align:start position:0% +of f Theta of + + + align:start position:0% +of f Theta of +x times first derivative of f Theta of + + align:start position:0% + + + + align:start position:0% + +X here is some super important stuff + + align:start position:0% +X here is some super important stuff + + + align:start position:0% +X here is some super important stuff +no I'm kidding and uh so you can still + + align:start position:0% +no I'm kidding and uh so you can still + + + align:start position:0% +no I'm kidding and uh so you can still +see that guy over there all right so + + align:start position:0% +see that guy over there all right so + + + align:start position:0% +see that guy over there all right so +it's just the square and then I divide + + align:start position:0% +it's just the square and then I divide + + + align:start position:0% +it's just the square and then I divide +by F Theta of x + + align:start position:0% + + + + align:start position:0% + +s + + align:start position:0% +s + + + align:start position:0% +s +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so here I have the second derivative + + align:start position:0% +so here I have the second derivative + + + align:start position:0% +so here I have the second derivative +times F itself and here I have the + + align:start position:0% +times F itself and here I have the + + + align:start position:0% +times F itself and here I have the +product of the first derivative itself + + align:start position:0% +product of the first derivative itself + + + align:start position:0% +product of the first derivative itself +with itself right so that's the square + + align:start position:0% +with itself right so that's the square + + + align:start position:0% +with itself right so that's the square +so now I'm going to integrate this guy + + align:start position:0% +so now I'm going to integrate this guy + + + align:start position:0% +so now I'm going to integrate this guy +so if I take the + + align:start position:0% +so if I take the + + + align:start position:0% +so if I take the +expectation of this thing here + + align:start position:0% +expectation of this thing here + + + align:start position:0% +expectation of this thing here +what I get is the integral so here the + + align:start position:0% +what I get is the integral so here the + + + align:start position:0% +what I get is the integral so here the +only thing that's going to happen when + + align:start position:0% +only thing that's going to happen when + + + align:start position:0% +only thing that's going to happen when +I'm going to take my integral is that + + align:start position:0% +I'm going to take my integral is that + + + align:start position:0% +I'm going to take my integral is that +this one of those squares is going to + + align:start position:0% +this one of those squares is going to + + + align:start position:0% +this one of those squares is going to +cancel against F Theta right so I'm + + align:start position:0% +cancel against F Theta right so I'm + + + align:start position:0% +cancel against F Theta right so I'm +going to get the second + + align:start position:0% + + + + align:start position:0% + +derivative um minus the second + + align:start position:0% +derivative um minus the second + + + align:start position:0% +derivative um minus the second +derivative squared + + align:start position:0% + + + + align:start position:0% + +and then I'm divided by F + + align:start position:0% + + + + align:start position:0% + +Theta and I know that this thing is + + align:start position:0% +Theta and I know that this thing is + + + align:start position:0% +Theta and I know that this thing is +equal to + + align:start position:0% + + + + align:start position:0% + +zero okay now one of this guy here uh + + align:start position:0% +zero okay now one of this guy here uh + + + align:start position:0% +zero okay now one of this guy here uh +sorry why do I have uh yeah so I have + + align:start position:0% +sorry why do I have uh yeah so I have + + + align:start position:0% +sorry why do I have uh yeah so I have +this guy here so this guy here is going + + align:start position:0% +this guy here so this guy here is going + + + align:start position:0% +this guy here so this guy here is going +to + + align:start position:0% +to + + + align:start position:0% +to +cancel right so this is what this is um + + align:start position:0% +cancel right so this is what this is um + + + align:start position:0% +cancel right so this is what this is um +uh equal + + align:start position:0% +uh equal + + + align:start position:0% +uh equal +to uh uh the + + align:start position:0% +to uh uh the + + + align:start position:0% +to uh uh the +integral of the + + align:start position:0% +integral of the + + + align:start position:0% +integral of the +partial so the second derivative of f + + align:start position:0% +partial so the second derivative of f + + + align:start position:0% +partial so the second derivative of f +Theta of + + align:start position:0% +Theta of + + + align:start position:0% +Theta of +X right because those two guys cancel + + align:start position:0% +X right because those two guys cancel + + + align:start position:0% +X right because those two guys cancel +minus the integral of the second + + align:start position:0% +minus the integral of the second + + + align:start position:0% +minus the integral of the second +[Music] + + align:start position:0% + + + + align:start position:0% + +derivative + + align:start position:0% +derivative + + + align:start position:0% +derivative +okay and + + align:start position:0% +okay and + + + align:start position:0% +okay and +um this is telling me what it's telling + + align:start position:0% +um this is telling me what it's telling + + + align:start position:0% +um this is telling me what it's telling +me that + + align:start position:0% +me that + + + align:start position:0% +me that +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +um + + align:start position:0% + + + + align:start position:0% + +uh yeah I'm losing one because I have + + align:start position:0% +uh yeah I'm losing one because I have + + + align:start position:0% +uh yeah I'm losing one because I have +some weird consequences thank you uh + + align:start position:0% + + + + align:start position:0% + +okay so this is actually yeah okay + + align:start position:0% +okay so this is actually yeah okay + + + align:start position:0% +okay so this is actually yeah okay +because now this is not + + align:start position:0% +because now this is not + + + align:start position:0% +because now this is not +well uh this is still positive so I know + + align:start position:0% +well uh this is still positive so I know + + + align:start position:0% +well uh this is still positive so I know +this thing I want to say that this thing + + align:start position:0% +this thing I want to say that this thing + + + align:start position:0% +this thing I want to say that this thing +is actually equal to + + align:start position:0% +is actually equal to + + + align:start position:0% +is actually equal to +zero but then it gives me some weird + + align:start position:0% +zero but then it gives me some weird + + + align:start position:0% +zero but then it gives me some weird +things which are that + + align:start position:0% +things which are that + + + align:start position:0% +things which are that +um I have the integral of a positive + + align:start position:0% +um I have the integral of a positive + + + align:start position:0% +um I have the integral of a positive +function which is equal to zero + + align:start position:0% + + + + align:start position:0% + +yeah that's what I'm thinking of doing + + align:start position:0% +yeah that's what I'm thinking of doing + + + align:start position:0% +yeah that's what I'm thinking of doing +but I'm going to get zero for this + + align:start position:0% +but I'm going to get zero for this + + + align:start position:0% +but I'm going to get zero for this +entire integral which means that have + + align:start position:0% +entire integral which means that have + + + align:start position:0% +entire integral which means that have +the integral of a positive function + + align:start position:0% +the integral of a positive function + + + align:start position:0% +the integral of a positive function +which is equal to zero which means that + + align:start position:0% +which is equal to zero which means that + + + align:start position:0% +which is equal to zero which means that +this function is equal to zero which uh + + align:start position:0% +this function is equal to zero which uh + + + align:start position:0% +this function is equal to zero which uh +sounds a little bad basically tells me + + align:start position:0% +sounds a little bad basically tells me + + + align:start position:0% +sounds a little bad basically tells me +that this function f Theta is + + align:start position:0% +that this function f Theta is + + + align:start position:0% +that this function f Theta is +linear + + align:start position:0% +linear + + + align:start position:0% +linear +um so I I went a little too far I + + align:start position:0% +um so I I went a little too far I + + + align:start position:0% +um so I I went a little too far I +believe because I only want to prove + + align:start position:0% +believe because I only want to prove + + + align:start position:0% +believe because I only want to prove +that the expectation of the second + + align:start position:0% +that the expectation of the second + + + align:start position:0% +that the expectation of the second +derivative uh + + align:start position:0% + + + + align:start position:0% + +um I want to show that the expectation + + align:start position:0% +um I want to show that the expectation + + + align:start position:0% +um I want to show that the expectation +of the I mean is that true actually that + + align:start position:0% + + + + align:start position:0% + +uh um yeah so I want to pull this out + + align:start position:0% + + + + align:start position:0% + +and uh so let's see if I keep rolling + + align:start position:0% +and uh so let's see if I keep rolling + + + align:start position:0% +and uh so let's see if I keep rolling +with this I'm going to get that well no + + align:start position:0% +with this I'm going to get that well no + + + align:start position:0% +with this I'm going to get that well no +because the fact that it's divided by F + + align:start position:0% +because the fact that it's divided by F + + + align:start position:0% +because the fact that it's divided by F +Theta means that indeed the second + + align:start position:0% +Theta means that indeed the second + + + align:start position:0% +Theta means that indeed the second +derivative is equal to zero so I cannot + + align:start position:0% +derivative is equal to zero so I cannot + + + align:start position:0% +derivative is equal to zero so I cannot +do this + + align:start position:0% + + + + align:start position:0% + +here okay uh maybe + + align:start position:0% + + + + align:start position:0% + +I that's + + align:start position:0% +I that's + + + align:start position:0% +I that's +correct um + + align:start position:0% +correct um + + + align:start position:0% +correct um +okay but um let's uh write it like this + + align:start position:0% +okay but um let's uh write it like this + + + align:start position:0% +okay but um let's uh write it like this +so you write so this is what this is the + + align:start position:0% +so you write so this is what this is the + + + align:start position:0% +so you write so this is what this is the +expectation of the uh the partial with + + align:start position:0% +expectation of the uh the partial with + + + align:start position:0% +expectation of the uh the partial with +respect to Theta of f Theta of x divided + + align:start position:0% +respect to Theta of f Theta of x divided + + + align:start position:0% +respect to Theta of f Theta of x divided +by F Theta of + + align:start position:0% +by F Theta of + + + align:start position:0% +by F Theta of +x squared right and this is the the + + align:start position:0% +x squared right and this is the the + + + align:start position:0% +x squared right and this is the the +exactly the derivative of f of the log + + align:start position:0% +exactly the derivative of f of the log + + + align:start position:0% +exactly the derivative of f of the log +right so that's indeed this thing is + + align:start position:0% +right so that's indeed this thing is + + + align:start position:0% +right so that's indeed this thing is +equal to the expectation with respect to + + align:start position:0% +equal to the expectation with respect to + + + align:start position:0% +equal to the expectation with respect to +theeta + + align:start position:0% +theeta + + + align:start position:0% +theeta +of the partial of + + align:start position:0% +of the partial of + + + align:start position:0% +of the partial of +L uh well of log of f + + align:start position:0% +L uh well of log of f + + + align:start position:0% +L uh well of log of f +Theta divided by partial + + align:start position:0% +Theta divided by partial + + + align:start position:0% +Theta divided by partial +Theta all right so this is one of the + + align:start position:0% +Theta all right so this is one of the + + + align:start position:0% +Theta all right so this is one of the +guys that I want squared so this is one + + align:start position:0% +guys that I want squared so this is one + + + align:start position:0% +guys that I want squared so this is one +of the guys that I + + align:start position:0% +of the guys that I + + + align:start position:0% +of the guys that I +want and uh this is actually equal so + + align:start position:0% +want and uh this is actually equal so + + + align:start position:0% +want and uh this is actually equal so +this will be equal to the + + align:start position:0% + + + + align:start position:0% + +expectation oh yeah right right right so + + align:start position:0% +expectation oh yeah right right right so + + + align:start position:0% +expectation oh yeah right right right so +this term should be equal to zero ABS + + align:start position:0% +this term should be equal to zero ABS + + + align:start position:0% +this term should be equal to zero ABS +yeah I wanted this was not zero you're + + align:start position:0% +yeah I wanted this was not zero you're + + + align:start position:0% +yeah I wanted this was not zero you're +absolutely right so at some point I got + + align:start position:0% +absolutely right so at some point I got + + + align:start position:0% +absolutely right so at some point I got +confused because I thought putting this + + align:start position:0% +confused because I thought putting this + + + align:start position:0% +confused because I thought putting this +equal to zero would mean that this is + + align:start position:0% +equal to zero would mean that this is + + + align:start position:0% +equal to zero would mean that this is +zero but this thing is not equal to zero + + align:start position:0% +zero but this thing is not equal to zero + + + align:start position:0% +zero but this thing is not equal to zero +so this thing you're right I take the + + align:start position:0% +so this thing you're right I take the + + + align:start position:0% +so this thing you're right I take the +same trick as before and this is + + align:start position:0% +same trick as before and this is + + + align:start position:0% +same trick as before and this is +actually equal to zero which means that + + align:start position:0% +actually equal to zero which means that + + + align:start position:0% +actually equal to zero which means that +now I have what's on the left hand side + + align:start position:0% +now I have what's on the left hand side + + + align:start position:0% +now I have what's on the left hand side +which is equal to what's on the right + + align:start position:0% +which is equal to what's on the right + + + align:start position:0% +which is equal to what's on the right +hand side and if I recap I get that e + + align:start position:0% +hand side and if I recap I get that e + + + align:start position:0% +hand side and if I recap I get that e +Theta of uh the second + + align:start position:0% +Theta of uh the second + + + align:start position:0% +Theta of uh the second +derivative of the log of f + + align:start position:0% +derivative of the log of f + + + align:start position:0% +derivative of the log of f +Theta is equal to minus because I had a + + align:start position:0% +Theta is equal to minus because I had a + + + align:start position:0% +Theta is equal to minus because I had a +minus sign here to the expectation with + + align:start position:0% +minus sign here to the expectation with + + + align:start position:0% +minus sign here to the expectation with +respect to Theta of log of f Theta + + align:start position:0% +respect to Theta of log of f Theta + + + align:start position:0% +respect to Theta of log of f Theta +divided by + + align:start position:0% +divided by + + + align:start position:0% +divided by +Theta squared okay thank you for uh + + align:start position:0% +Theta squared okay thank you for uh + + + align:start position:0% +Theta squared okay thank you for uh +being on on watch when I'm falling apart + + align:start position:0% +being on on watch when I'm falling apart + + + align:start position:0% +being on on watch when I'm falling apart +all right so this is exactly what you + + align:start position:0% +all right so this is exactly what you + + + align:start position:0% +all right so this is exactly what you +have here except that both terms have + + align:start position:0% +have here except that both terms have + + + align:start position:0% +have here except that both terms have +been put on the same side all right so + + align:start position:0% +been put on the same side all right so + + + align:start position:0% +been put on the same side all right so +those things are going to be useful to + + align:start position:0% +those things are going to be useful to + + + align:start position:0% +those things are going to be useful to +us so maybe we should write them + + align:start position:0% +us so maybe we should write them + + + align:start position:0% +us so maybe we should write them +somewhere uh + + align:start position:0% + + + + align:start position:0% + +here and then we have that the + + align:start position:0% +here and then we have that the + + + align:start position:0% +here and then we have that the +expectation of the uh second derivative + + align:start position:0% +expectation of the uh second derivative + + + align:start position:0% +expectation of the uh second derivative +of the + + align:start position:0% + + + + align:start position:0% + +log is equal to + + align:start position:0% +log is equal to + + + align:start position:0% +log is equal to +minus uh + + align:start position:0% +minus uh + + + align:start position:0% +minus uh +expectation of the square of the first + + align:start position:0% + + + + align:start position:0% + +derivative okay and this is indeed my + + align:start position:0% +derivative okay and this is indeed my + + + align:start position:0% +derivative okay and this is indeed my +fisser information this is just telling + + align:start position:0% +fisser information this is just telling + + + align:start position:0% +fisser information this is just telling +me what is the second derivative of uh + + align:start position:0% +me what is the second derivative of uh + + + align:start position:0% +me what is the second derivative of uh +my log likelihood at Theta right so + + align:start position:0% +my log likelihood at Theta right so + + + align:start position:0% +my log likelihood at Theta right so +everything is with respect to Theta when + + align:start position:0% +everything is with respect to Theta when + + + align:start position:0% +everything is with respect to Theta when +I take these expectations and so it + + align:start position:0% +I take these expectations and so it + + + align:start position:0% +I take these expectations and so it +tells me that the expectation of the log + + align:start position:0% +tells me that the expectation of the log + + + align:start position:0% +tells me that the expectation of the log +likely of the of the uh second + + align:start position:0% +likely of the of the uh second + + + align:start position:0% +likely of the of the uh second +derivative at least first of all what + + align:start position:0% +derivative at least first of all what + + + align:start position:0% +derivative at least first of all what +it's telling me is that it's concave + + align:start position:0% +it's telling me is that it's concave + + + align:start position:0% +it's telling me is that it's concave +right because the second derivative of + + align:start position:0% +right because the second derivative of + + + align:start position:0% +right because the second derivative of +this thing which is the second + + align:start position:0% +this thing which is the second + + + align:start position:0% +this thing which is the second +derivative of the K Divergence is + + align:start position:0% +derivative of the K Divergence is + + + align:start position:0% +derivative of the K Divergence is +actually minus something which is must + + align:start position:0% +actually minus something which is must + + + align:start position:0% +actually minus something which is must +be non- negative and so it's telling me + + align:start position:0% +be non- negative and so it's telling me + + + align:start position:0% +be non- negative and so it's telling me +that it's concave here at this + + align:start position:0% +that it's concave here at this + + + align:start position:0% +that it's concave here at this +maximum okay and in particular it's also + + align:start position:0% +maximum okay and in particular it's also + + + align:start position:0% +maximum okay and in particular it's also +telling me that it has to be strictly + + align:start position:0% +telling me that it has to be strictly + + + align:start position:0% +telling me that it has to be strictly +positive unless the derivative of f is + + align:start position:0% +positive unless the derivative of f is + + + align:start position:0% +positive unless the derivative of f is +equal to zero so if unless f is constant + + align:start position:0% +equal to zero so if unless f is constant + + + align:start position:0% +equal to zero so if unless f is constant +then uh I don't have a I'm not it's not + + align:start position:0% +then uh I don't have a I'm not it's not + + + align:start position:0% +then uh I don't have a I'm not it's not +going to + + align:start position:0% +going to + + + align:start position:0% +going to +change all right + + align:start position:0% +change all right + + + align:start position:0% +change all right +do you have a + + align:start position:0% +do you have a + + + align:start position:0% +do you have a +question so now let's use + + align:start position:0% +question so now let's use + + + align:start position:0% +question so now let's use +this so what does my log likelihood look + + align:start position:0% +this so what does my log likelihood look + + + align:start position:0% +this so what does my log likelihood look +like when I actually comput it for this + + align:start position:0% +like when I actually comput it for this + + + align:start position:0% +like when I actually comput it for this +canonical exponential family right I + + align:start position:0% +canonical exponential family right I + + + align:start position:0% +canonical exponential family right I +mean we have this exponential function + + align:start position:0% +mean we have this exponential function + + + align:start position:0% +mean we have this exponential function +so taking the log should make my life + + align:start position:0% +so taking the log should make my life + + + align:start position:0% +so taking the log should make my life +much easier and indeed it does so if I + + align:start position:0% +much easier and indeed it does so if I + + + align:start position:0% +much easier and indeed it does so if I +look at the + + align:start position:0% + + + + align:start position:0% + +canonical what I have is that the log of + + align:start position:0% +canonical what I have is that the log of + + + align:start position:0% +canonical what I have is that the log of +f + + align:start position:0% + + + + align:start position:0% + +Theta of + + align:start position:0% +Theta of + + + align:start position:0% +Theta of +X well it's equal simply to Y Theta + + align:start position:0% +X well it's equal simply to Y Theta + + + align:start position:0% +X well it's equal simply to Y Theta +minus B of + + align:start position:0% +minus B of + + + align:start position:0% +minus B of +theta divided five plus this function + + align:start position:0% +theta divided five plus this function + + + align:start position:0% +theta divided five plus this function +that only depends that does not depend + + align:start position:0% +that only depends that does not depend + + + align:start position:0% +that only depends that does not depend +on + + align:start position:0% +on + + + align:start position:0% +on +Theta + + align:start position:0% +Theta + + + align:start position:0% +Theta +okay so let's see what this tells me + + align:start position:0% +okay so let's see what this tells me + + + align:start position:0% +okay so let's see what this tells me +what do let's just plug in those + + align:start position:0% +what do let's just plug in those + + + align:start position:0% +what do let's just plug in those +equalities in there right I mean I can + + align:start position:0% +equalities in there right I mean I can + + + align:start position:0% +equalities in there right I mean I can +take the derivative of the right hand + + align:start position:0% +take the derivative of the right hand + + + align:start position:0% +take the derivative of the right hand +side and just say that in expectation is + + align:start position:0% +side and just say that in expectation is + + + align:start position:0% +side and just say that in expectation is +equal to zero so if I start looking at + + align:start position:0% +equal to zero so if I start looking at + + + align:start position:0% +equal to zero so if I start looking at +the + + align:start position:0% +the + + + align:start position:0% +the +derivative this is equal to what well + + align:start position:0% +derivative this is equal to what well + + + align:start position:0% +derivative this is equal to what well +here I'm going to pick up only uh y + + align:start position:0% +here I'm going to pick up only uh y + + + align:start position:0% +here I'm going to pick up only uh y +sorry this is a function of + + align:start position:0% +sorry this is a function of + + + align:start position:0% +sorry this is a function of +Y uh I'm going to pick only + + align:start position:0% + + + + align:start position:0% + +uh all right I was talking about + + align:start position:0% +uh all right I was talking about + + + align:start position:0% +uh all right I was talking about +likelihood so I actually need to put the + + align:start position:0% +likelihood so I actually need to put the + + + align:start position:0% +likelihood so I actually need to put the +random variable here uh so I get y minus + + align:start position:0% +random variable here uh so I get y minus + + + align:start position:0% +random variable here uh so I get y minus +the derivative of B of theta since it's + + align:start position:0% +the derivative of B of theta since it's + + + align:start position:0% +the derivative of B of theta since it's +only a function of theta I'm just going + + align:start position:0% +only a function of theta I'm just going + + + align:start position:0% +only a function of theta I'm just going +to write B Prime is that okay rather + + align:start position:0% +to write B Prime is that okay rather + + + align:start position:0% +to write B Prime is that okay rather +than having the partial with respect to + + align:start position:0% +than having the partial with respect to + + + align:start position:0% +than having the partial with respect to +Theta then this is a constant this does + + align:start position:0% +Theta then this is a constant this does + + + align:start position:0% +Theta then this is a constant this does +not depend on Theta so it goes + + align:start position:0% +not depend on Theta so it goes + + + align:start position:0% +not depend on Theta so it goes +away + + align:start position:0% + + + + align:start position:0% + +okay so if I start taking the + + align:start position:0% +okay so if I start taking the + + + align:start position:0% +okay so if I start taking the +expectation of this + + align:start position:0% + + + + align:start position:0% + +guy I get the expectation of this + + align:start position:0% +guy I get the expectation of this + + + align:start position:0% +guy I get the expectation of this +guy which is the expectation of + + align:start position:0% +guy which is the expectation of + + + align:start position:0% +guy which is the expectation of +Y minus well this does not depend on y + + align:start position:0% +Y minus well this does not depend on y + + + align:start position:0% +Y minus well this does not depend on y +so it's just itself B Prime of theta and + + align:start position:0% +so it's just itself B Prime of theta and + + + align:start position:0% +so it's just itself B Prime of theta and +the whole thing is divided by five but + + align:start position:0% +the whole thing is divided by five but + + + align:start position:0% +the whole thing is divided by five but +from my first equality over there I know + + align:start position:0% +from my first equality over there I know + + + align:start position:0% +from my first equality over there I know +that this thing is actually equal to + + align:start position:0% +that this thing is actually equal to + + + align:start position:0% +that this thing is actually equal to +zero right we just proved that so in + + align:start position:0% +zero right we just proved that so in + + + align:start position:0% +zero right we just proved that so in +particular it means that since f is non + + align:start position:0% +particular it means that since f is non + + + align:start position:0% +particular it means that since f is non +zero it means that this guy must be + + align:start position:0% +zero it means that this guy must be + + + align:start position:0% +zero it means that this guy must be +equal to this guy or F is not Infinity + + align:start position:0% +equal to this guy or F is not Infinity + + + align:start position:0% +equal to this guy or F is not Infinity +say and so that + + align:start position:0% +say and so that + + + align:start position:0% +say and so that +implies that the expectation with + + align:start position:0% +implies that the expectation with + + + align:start position:0% +implies that the expectation with +respect to Theta of + + align:start position:0% +respect to Theta of + + + align:start position:0% +respect to Theta of +Y is equal to B Prime of theta + + align:start position:0% + + + + align:start position:0% + +I'm sorry you're not registered in this + + align:start position:0% +I'm sorry you're not registered in this + + + align:start position:0% +I'm sorry you're not registered in this +class I'm going to have to ask you to + + align:start position:0% +class I'm going to have to ask you to + + + align:start position:0% +class I'm going to have to ask you to +leave I'm not + + align:start position:0% + + + + align:start position:0% + +kidding you are I've never seen you here + + align:start position:0% +kidding you are I've never seen you here + + + align:start position:0% +kidding you are I've never seen you here +I mean I saw you for the first + + align:start position:0% +I mean I saw you for the first + + + align:start position:0% +I mean I saw you for the first +Lector + + align:start position:0% +Lector + + + align:start position:0% +Lector +okay um all right so e Theta of Y is + + align:start position:0% +okay um all right so e Theta of Y is + + + align:start position:0% +okay um all right so e Theta of Y is +equal to B Prime of theta everybody + + align:start position:0% +equal to B Prime of theta everybody + + + align:start position:0% +equal to B Prime of theta everybody +agrees with + + align:start position:0% + + + + align:start position:0% + +that so this is actually nice because if + + align:start position:0% +that so this is actually nice because if + + + align:start position:0% +that so this is actually nice because if +I tell you okay I told you if I give you + + align:start position:0% +I tell you okay I told you if I give you + + + align:start position:0% +I tell you okay I told you if I give you +a an exponential family the only thing I + + align:start position:0% +a an exponential family the only thing I + + + align:start position:0% +a an exponential family the only thing I +really need to tell you is what B Theta + + align:start position:0% +really need to tell you is what B Theta + + + align:start position:0% +really need to tell you is what B Theta +is and if I give you B of theta then you + + align:start position:0% +is and if I give you B of theta then you + + + align:start position:0% +is and if I give you B of theta then you +know Computing a derivative is actually + + align:start position:0% +know Computing a derivative is actually + + + align:start position:0% +know Computing a derivative is actually +much easier than having to integrate y + + align:start position:0% +much easier than having to integrate y + + + align:start position:0% +much easier than having to integrate y +against the density itself I mean you + + align:start position:0% +against the density itself I mean you + + + align:start position:0% +against the density itself I mean you +could really have fun and try to compute + + align:start position:0% +could really have fun and try to compute + + + align:start position:0% +could really have fun and try to compute +this which you would be able to do + + align:start position:0% + + + + align:start position:0% + +right and then there's the plus C of Y + + align:start position:0% +right and then there's the plus C of Y + + + align:start position:0% +right and then there's the plus C of Y +five blah blah blah Dy and that's the + + align:start position:0% +five blah blah blah Dy and that's the + + + align:start position:0% +five blah blah blah Dy and that's the +way you would actually compute this + + align:start position:0% +way you would actually compute this + + + align:start position:0% +way you would actually compute this +thing but that would be uh that would be + + align:start position:0% +thing but that would be uh that would be + + + align:start position:0% +thing but that would be uh that would be +really sorry this this guy is here that + + align:start position:0% +really sorry this this guy is here that + + + align:start position:0% +really sorry this this guy is here that +would be painful right I don't know what + + align:start position:0% +would be painful right I don't know what + + + align:start position:0% +would be painful right I don't know what +this normalization looks like so I would + + align:start position:0% +this normalization looks like so I would + + + align:start position:0% +this normalization looks like so I would +have to also explicit that so I can + + align:start position:0% +have to also explicit that so I can + + + align:start position:0% +have to also explicit that so I can +actually compute this thing and you know + + align:start position:0% +actually compute this thing and you know + + + align:start position:0% +actually compute this thing and you know +just the same way if you want to compute + + align:start position:0% +just the same way if you want to compute + + + align:start position:0% +just the same way if you want to compute +the expectation of a + + align:start position:0% +the expectation of a + + + align:start position:0% +the expectation of a +gaan well okay the expectation of a gaan + + align:start position:0% +gaan well okay the expectation of a gaan + + + align:start position:0% +gaan well okay the expectation of a gaan +is not the most difficult one but you + + align:start position:0% +is not the most difficult one but you + + + align:start position:0% +is not the most difficult one but you +know even if you compute the expectation + + align:start position:0% +know even if you compute the expectation + + + align:start position:0% +know even if you compute the expectation +of a Pon you start to have to work a + + align:start position:0% +of a Pon you start to have to work a + + + align:start position:0% +of a Pon you start to have to work a +little bit there's a few things that you + + align:start position:0% +little bit there's a few things that you + + + align:start position:0% +little bit there's a few things that you +have to work through here I'm just + + align:start position:0% +have to work through here I'm just + + + align:start position:0% +have to work through here I'm just +telling you all you have to know is what + + align:start position:0% +telling you all you have to know is what + + + align:start position:0% +telling you all you have to know is what +B of theta is and then you can just take + + align:start position:0% +B of theta is and then you can just take + + + align:start position:0% +B of theta is and then you can just take +the + + align:start position:0% +the + + + align:start position:0% +the +derivative let's see what the second + + align:start position:0% +derivative let's see what the second + + + align:start position:0% +derivative let's see what the second +equality is going to give + + align:start position:0% + + + + align:start position:0% + +us okay so what is the second equality + + align:start position:0% +us okay so what is the second equality + + + align:start position:0% +us okay so what is the second equality +quity uh it's telling me that if I look + + align:start position:0% +quity uh it's telling me that if I look + + + align:start position:0% +quity uh it's telling me that if I look +at the second derivative and then I took + + align:start position:0% +at the second derivative and then I took + + + align:start position:0% +at the second derivative and then I took +it I take its expectation uh I'm gonna + + align:start position:0% +it I take its expectation uh I'm gonna + + + align:start position:0% +it I take its expectation uh I'm gonna +have something which is equal to + + align:start position:0% +have something which is equal to + + + align:start position:0% +have something which is equal to +negative uh this guy squared we've + + align:start position:0% +negative uh this guy squared we've + + + align:start position:0% +negative uh this guy squared we've +already comp uh sorry that that was the + + align:start position:0% +already comp uh sorry that that was the + + + align:start position:0% +already comp uh sorry that that was the +log + + align:start position:0% + + + + align:start position:0% + +right we've already computed this uh + + align:start position:0% +right we've already computed this uh + + + align:start position:0% +right we've already computed this uh +this first derivative of the likelihood + + align:start position:0% +this first derivative of the likelihood + + + align:start position:0% +this first derivative of the likelihood +right it's just the expectation of the + + align:start position:0% +right it's just the expectation of the + + + align:start position:0% +right it's just the expectation of the +square of this thing here + + align:start position:0% +square of this thing here + + + align:start position:0% +square of this thing here +right so + + align:start position:0% +right so + + + align:start position:0% +right so +expectation of the derivative with + + align:start position:0% +expectation of the derivative with + + + align:start position:0% +expectation of the derivative with +respect to Theta of log F Theta of x + + align:start position:0% +respect to Theta of log F Theta of x + + + align:start position:0% +respect to Theta of log F Theta of x +divided partial + + align:start position:0% +divided partial + + + align:start position:0% +divided partial +Theta + + align:start position:0% +Theta + + + align:start position:0% +Theta +Square uh this is equal to the + + align:start position:0% +Square uh this is equal to the + + + align:start position:0% +Square uh this is equal to the +expectation of the square of Y minus B + + align:start position:0% +expectation of the square of Y minus B + + + align:start position:0% +expectation of the square of Y minus B +Theta ID + + align:start position:0% +Theta ID + + + align:start position:0% +Theta ID +5^ + + align:start position:0% +5^ + + + align:start position:0% +5^ +squar right B Prime Theta + + align:start position:0% +squar right B Prime Theta + + + align:start position:0% +squar right B Prime Theta +square and uh + + align:start position:0% +square and uh + + + align:start position:0% +square and uh +uh okay sorry I'm actually going to move + + align:start position:0% +uh okay sorry I'm actually going to move + + + align:start position:0% +uh okay sorry I'm actually going to move +on with + + align:start position:0% +on with + + + align:start position:0% +on with +the okay and uh so if I start Computing + + align:start position:0% +the okay and uh so if I start Computing + + + align:start position:0% +the okay and uh so if I start Computing +what is this thing well this we just + + align:start position:0% +what is this thing well this we just + + + align:start position:0% +what is this thing well this we just +agreed that this was + + align:start position:0% + + + + align:start position:0% + +what the expectation of theta + + align:start position:0% +what the expectation of theta + + + align:start position:0% +what the expectation of theta +right so that's just the expectation + + align:start position:0% +right so that's just the expectation + + + align:start position:0% +right so that's just the expectation +sorry the expectation of Y we just + + align:start position:0% +sorry the expectation of Y we just + + + align:start position:0% +sorry the expectation of Y we just +computed here + + align:start position:0% + + + + align:start position:0% + +yeah that's B Prime there's a derivative + + align:start position:0% + + + + align:start position:0% + +here + + align:start position:0% +here + + + align:start position:0% +here +okay so now uh this is what how this is + + align:start position:0% + + + + align:start position:0% + +simply anyone + + align:start position:0% + + + + align:start position:0% + +I'm sorry variance of Y but there's the + + align:start position:0% +I'm sorry variance of Y but there's the + + + align:start position:0% +I'm sorry variance of Y but there's the +scaling by five square + + align:start position:0% + + + + align:start position:0% + +right okay so that's so this is negative + + align:start position:0% +right okay so that's so this is negative + + + align:start position:0% +right okay so that's so this is negative +of the right hand side of our inequality + + align:start position:0% +of the right hand side of our inequality + + + align:start position:0% +of the right hand side of our inequality +and now I just have to take one more + + align:start position:0% +and now I just have to take one more + + + align:start position:0% +and now I just have to take one more +derivative uh to this guy right so if + + align:start position:0% +derivative uh to this guy right so if + + + align:start position:0% +derivative uh to this guy right so if +now if I look at and if I look at the + + align:start position:0% +now if I look at and if I look at the + + + align:start position:0% +now if I look at and if I look at the +left hand side now I have that the + + align:start position:0% +left hand side now I have that the + + + align:start position:0% +left hand side now I have that the +partial itive the second derivative of + + align:start position:0% +partial itive the second derivative of + + + align:start position:0% +partial itive the second derivative of +log of f Theta of Y divid partial of + + align:start position:0% +log of f Theta of Y divid partial of + + + align:start position:0% +log of f Theta of Y divid partial of +theta + + align:start position:0% +theta + + + align:start position:0% +theta +squared so this thing is equal to well + + align:start position:0% +squared so this thing is equal to well + + + align:start position:0% +squared so this thing is equal to well +now I'm not left with much the Y part is + + align:start position:0% +now I'm not left with much the Y part is + + + align:start position:0% +now I'm not left with much the Y part is +going to go away and I'm left only with + + align:start position:0% +going to go away and I'm left only with + + + align:start position:0% +going to go away and I'm left only with +the second derivative of theta minus the + + align:start position:0% +the second derivative of theta minus the + + + align:start position:0% +the second derivative of theta minus the +second derivative of theta divid + + align:start position:0% + + + + align:start position:0% + +five okay + + align:start position:0% +five okay + + + align:start position:0% +five okay +so if I take + + align:start position:0% +so if I take + + + align:start position:0% +so if I take +expectation well it just doesn't + + align:start position:0% +expectation well it just doesn't + + + align:start position:0% +expectation well it just doesn't +change this is deterministic so now what + + align:start position:0% +change this is deterministic so now what + + + align:start position:0% +change this is deterministic so now what +I've established is that this guy is + + align:start position:0% +I've established is that this guy is + + + align:start position:0% +I've established is that this guy is +equal to negative this guy so those two + + align:start position:0% +equal to negative this guy so those two + + + align:start position:0% +equal to negative this guy so those two +things are the signs are going to go + + align:start position:0% +things are the signs are going to go + + + align:start position:0% +things are the signs are going to go +away and so this implies that the + + align:start position:0% +away and so this implies that the + + + align:start position:0% +away and so this implies that the +variance of Y is equal to B prime prime + + align:start position:0% +variance of Y is equal to B prime prime + + + align:start position:0% +variance of Y is equal to B prime prime +Theta and then I have a 5 Square in + + align:start position:0% +Theta and then I have a 5 Square in + + + align:start position:0% +Theta and then I have a 5 Square in +denominator that cancels only one the + + align:start position:0% +denominator that cancels only one the + + + align:start position:0% +denominator that cancels only one the +five in the denominator that cancels + + align:start position:0% +five in the denominator that cancels + + + align:start position:0% +five in the denominator that cancels +only one of the five squares so it's + + align:start position:0% +only one of the five squares so it's + + + align:start position:0% +only one of the five squares so it's +time + + align:start position:0% + + + + align:start position:0% + +five so now I have that my second + + align:start position:0% +five so now I have that my second + + + align:start position:0% +five so now I have that my second +derivative since I know f is completely + + align:start position:0% +derivative since I know f is completely + + + align:start position:0% +derivative since I know f is completely +determined determining the + + align:start position:0% +determined determining the + + + align:start position:0% +determined determining the +variance all right and so basically + + align:start position:0% +variance all right and so basically + + + align:start position:0% +variance all right and so basically +that's what B that's why B is called the + + align:start position:0% +that's what B that's why B is called the + + + align:start position:0% +that's what B that's why B is called the +cumulant generating function is not + + align:start position:0% +cumulant generating function is not + + + align:start position:0% +cumulant generating function is not +generating moments but cumulants but + + align:start position:0% +generating moments but cumulants but + + + align:start position:0% +generating moments but cumulants but +cumulants in this case correct respond + + align:start position:0% +cumulants in this case correct respond + + + align:start position:0% +cumulants in this case correct respond +basically to the moments at least for + + align:start position:0% +basically to the moments at least for + + + align:start position:0% +basically to the moments at least for +the first two if I start going F farther + + align:start position:0% +the first two if I start going F farther + + + align:start position:0% +the first two if I start going F farther +I'm not going to have I'm going to have + + align:start position:0% +I'm not going to have I'm going to have + + + align:start position:0% +I'm not going to have I'm going to have +more combinations of the expectation of + + align:start position:0% +more combinations of the expectation of + + + align:start position:0% +more combinations of the expectation of +Y3 Y 2 and why itself + + align:start position:0% +Y3 Y 2 and why itself + + + align:start position:0% +Y3 Y 2 and why itself +okay so but you know as we know those + + align:start position:0% +okay so but you know as we know those + + + align:start position:0% +okay so but you know as we know those +are the ones that are usually the most + + align:start position:0% +are the ones that are usually the most + + + align:start position:0% +are the ones that are usually the most +useful at least if we're interested in a + + align:start position:0% +useful at least if we're interested in a + + + align:start position:0% +useful at least if we're interested in a +SYM totic performance the central limit + + align:start position:0% +SYM totic performance the central limit + + + align:start position:0% +SYM totic performance the central limit +theorem tells us that all that matters + + align:start position:0% +theorem tells us that all that matters + + + align:start position:0% +theorem tells us that all that matters +are the first two moments and then the + + align:start position:0% +are the first two moments and then the + + + align:start position:0% +are the first two moments and then the +rest is just going to go and say well it + + align:start position:0% +rest is just going to go and say well it + + + align:start position:0% +rest is just going to go and say well it +doesn't matter it's all going to a + + align:start position:0% +doesn't matter it's all going to a + + + align:start position:0% +doesn't matter it's all going to a +normal anyway + + align:start position:0% +normal anyway + + + align:start position:0% +normal anyway +so let's go to a Pon for example right + + align:start position:0% +so let's go to a Pon for example right + + + align:start position:0% +so let's go to a Pon for example right +so if I had a Pon + + align:start position:0% + + + + align:start position:0% + +distribution all right so this is a + + align:start position:0% +distribution all right so this is a + + + align:start position:0% +distribution all right so this is a +discrete + + align:start position:0% +discrete + + + align:start position:0% +discrete +distribution and uh what I know is that + + align:start position:0% +distribution and uh what I know is that + + + align:start position:0% +distribution and uh what I know is that +uh so F uh let me call uh mu the + + align:start position:0% +uh so F uh let me call uh mu the + + + align:start position:0% +uh so F uh let me call uh mu the +parameter of Y this is + + align:start position:0% +parameter of Y this is + + + align:start position:0% +parameter of Y this is +uh well okay so it's mu to the Y divided + + align:start position:0% +uh well okay so it's mu to the Y divided + + + align:start position:0% +uh well okay so it's mu to the Y divided +by y factorial exponential minus mu okay + + align:start position:0% +by y factorial exponential minus mu okay + + + align:start position:0% +by y factorial exponential minus mu okay +so mu is usually called Lambda and Y is + + align:start position:0% +so mu is usually called Lambda and Y is + + + align:start position:0% +so mu is usually called Lambda and Y is +usually called X that's why it takes me + + align:start position:0% +usually called X that's why it takes me + + + align:start position:0% +usually called X that's why it takes me +a little bit of time but usually it's + + align:start position:0% +a little bit of time but usually it's + + + align:start position:0% +a little bit of time but usually it's +Lambda to the X over factorial X + + align:start position:0% +Lambda to the X over factorial X + + + align:start position:0% +Lambda to the X over factorial X +exponential minus Lambda this thing + + align:start position:0% +exponential minus Lambda this thing + + + align:start position:0% +exponential minus Lambda this thing +clearly since this is just the series + + align:start position:0% +clearly since this is just the series + + + align:start position:0% +clearly since this is just the series +expansion of the exponential when I sum + + align:start position:0% +expansion of the exponential when I sum + + + align:start position:0% +expansion of the exponential when I sum +those things from zero to Infinity this + + align:start position:0% +those things from zero to Infinity this + + + align:start position:0% +those things from zero to Infinity this +thing sums to one but then if I wanted + + align:start position:0% +thing sums to one but then if I wanted + + + align:start position:0% +thing sums to one but then if I wanted +to start understanding what the + + align:start position:0% +to start understanding what the + + + align:start position:0% +to start understanding what the +expectation of this thing is uh right so + + align:start position:0% +expectation of this thing is uh right so + + + align:start position:0% +expectation of this thing is uh right so +if I want to understand the expectations + + align:start position:0% +if I want to understand the expectations + + + align:start position:0% +if I want to understand the expectations +with respect to mu of uh + + align:start position:0% +with respect to mu of uh + + + align:start position:0% +with respect to mu of uh +y then I would have to compute the sum + + align:start position:0% +y then I would have to compute the sum + + + align:start position:0% +y then I would have to compute the sum +from k equal 0 or let's say yeah from k + + align:start position:0% +from k equal 0 or let's say yeah from k + + + align:start position:0% +from k equal 0 or let's say yeah from k +equals z to Infinity of um y times mu + + align:start position:0% +equals z to Infinity of um y times mu + + + align:start position:0% +equals z to Infinity of um y times mu +sorry of K * mu to the K Over factorial + + align:start position:0% +sorry of K * mu to the K Over factorial + + + align:start position:0% +sorry of K * mu to the K Over factorial +K exponential minus mu which means that + + align:start position:0% +K exponential minus mu which means that + + + align:start position:0% +K exponential minus mu which means that +I would essentially have to + + align:start position:0% +I would essentially have to + + + align:start position:0% +I would essentially have to +take the derivative + + align:start position:0% + + + + align:start position:0% + +okay um that I would have to take the + + align:start position:0% +okay um that I would have to take the + + + align:start position:0% +okay um that I would have to take the +derivative of my um uh series uh in the + + align:start position:0% +derivative of my um uh series uh in the + + + align:start position:0% +derivative of my um uh series uh in the +end so you know I can do this this is a + + align:start position:0% +end so you know I can do this this is a + + + align:start position:0% +end so you know I can do this this is a +standard exercise you've probably done + + align:start position:0% +standard exercise you've probably done + + + align:start position:0% +standard exercise you've probably done +it when you took probability but let's + + align:start position:0% +it when you took probability but let's + + + align:start position:0% +it when you took probability but let's +see if we can actually just Ser it off + + align:start position:0% +see if we can actually just Ser it off + + + align:start position:0% +see if we can actually just Ser it off +from the first derivative of B so to do + + align:start position:0% +from the first derivative of B so to do + + + align:start position:0% +from the first derivative of B so to do +that we need to write this in the form + + align:start position:0% +that we need to write this in the form + + + align:start position:0% +that we need to write this in the form +of an exponential where there's one + + align:start position:0% +of an exponential where there's one + + + align:start position:0% +of an exponential where there's one +parameter that captures mu that + + align:start position:0% +parameter that captures mu that + + + align:start position:0% +parameter that captures mu that +interacts with Y just doing this + + align:start position:0% +interacts with Y just doing this + + + align:start position:0% +interacts with Y just doing this +parameter times Y and then something + + align:start position:0% +parameter times Y and then something + + + align:start position:0% +parameter times Y and then something +that depends only on Y and then + + align:start position:0% +that depends only on Y and then + + + align:start position:0% +that depends only on Y and then +something that depends only on uh sorry + + align:start position:0% +something that depends only on uh sorry + + + align:start position:0% +something that depends only on uh sorry +something depends only on on me that's + + align:start position:0% +something depends only on on me that's + + + align:start position:0% +something depends only on on me that's +the important one that's going to be our + + align:start position:0% +the important one that's going to be our + + + align:start position:0% +the important one that's going to be our +B and then there's going to be something + + align:start position:0% +B and then there's going to be something + + + align:start position:0% +B and then there's going to be something +that depends only on uh y okay so let's + + align:start position:0% +that depends only on uh y okay so let's + + + align:start position:0% +that depends only on uh y okay so let's +write this and check that this F mu + + align:start position:0% +write this and check that this F mu + + + align:start position:0% +write this and check that this F mu +indeed belongs to this canonical + + align:start position:0% +indeed belongs to this canonical + + + align:start position:0% +indeed belongs to this canonical +exponential family so I definitely have + + align:start position:0% +exponential family so I definitely have + + + align:start position:0% +exponential family so I definitely have +an exponential that comes from this guy + + align:start position:0% +an exponential that comes from this guy + + + align:start position:0% +an exponential that comes from this guy +so I have minus mu and then this thing + + align:start position:0% +so I have minus mu and then this thing + + + align:start position:0% +so I have minus mu and then this thing +is going to give me what it's going to + + align:start position:0% +is going to give me what it's going to + + + align:start position:0% +is going to give me what it's going to +give me plus y log mu + + align:start position:0% +give me plus y log mu + + + align:start position:0% +give me plus y log mu +and then I'm going to have minus log of + + align:start position:0% +and then I'm going to have minus log of + + + align:start position:0% +and then I'm going to have minus log of +Y factorial + + align:start position:0% + + + + align:start position:0% + +right okay so clearly I have a term that + + align:start position:0% +right okay so clearly I have a term that + + + align:start position:0% +right okay so clearly I have a term that +depends only on mu a terms that depend + + align:start position:0% +depends only on mu a terms that depend + + + align:start position:0% +depends only on mu a terms that depend +only on Y and I have a product of Y and + + align:start position:0% +only on Y and I have a product of Y and + + + align:start position:0% +only on Y and I have a product of Y and +something that depends on me if I want + + align:start position:0% +something that depends on me if I want + + + align:start position:0% +something that depends on me if I want +to be canonical I must have this to be + + align:start position:0% +to be canonical I must have this to be + + + align:start position:0% +to be canonical I must have this to be +exactly the parameter Theta + + align:start position:0% +exactly the parameter Theta + + + align:start position:0% +exactly the parameter Theta +itself okay so I'm going to call this + + align:start position:0% +itself okay so I'm going to call this + + + align:start position:0% +itself okay so I'm going to call this +guy + + align:start position:0% +guy + + + align:start position:0% +guy +Theta okay so Theta is log mu which + + align:start position:0% +Theta okay so Theta is log mu which + + + align:start position:0% +Theta okay so Theta is log mu which +means that mu is equal to e to the Theta + + align:start position:0% +means that mu is equal to e to the Theta + + + align:start position:0% +means that mu is equal to e to the Theta +and so wherever I see mu I'm going to + + align:start position:0% +and so wherever I see mu I'm going to + + + align:start position:0% +and so wherever I see mu I'm going to +replace it by U to the Theta because my + + align:start position:0% +replace it by U to the Theta because my + + + align:start position:0% +replace it by U to the Theta because my +new parameter now is Theta so this is + + align:start position:0% +new parameter now is Theta so this is + + + align:start position:0% +new parameter now is Theta so this is +what this is equal to + + align:start position:0% +what this is equal to + + + align:start position:0% +what this is equal to +exponential y * Theta and then I'm going + + align:start position:0% +exponential y * Theta and then I'm going + + + align:start position:0% +exponential y * Theta and then I'm going +to have minus E of + + align:start position:0% +to have minus E of + + + align:start position:0% +to have minus E of +theta and then who cares something that + + align:start position:0% +theta and then who cares something that + + + align:start position:0% +theta and then who cares something that +depends only on on you so this is my C + + align:start position:0% +depends only on on you so this is my C + + + align:start position:0% +depends only on on you so this is my C +of Y and F is equal to one in this case + + align:start position:0% +of Y and F is equal to one in this case + + + align:start position:0% +of Y and F is equal to one in this case +uh uh so that's all I care about so let + + align:start position:0% +uh uh so that's all I care about so let + + + align:start position:0% +uh uh so that's all I care about so let +me I mean let's let's use it + + align:start position:0% +me I mean let's let's use it + + + align:start position:0% +me I mean let's let's use it +right okay so this is my canonical + + align:start position:0% +right okay so this is my canonical + + + align:start position:0% +right okay so this is my canonical +exponential + + align:start position:0% +exponential + + + align:start position:0% +exponential +Family Y interact with Theta exactly + + align:start position:0% +Family Y interact with Theta exactly + + + align:start position:0% +Family Y interact with Theta exactly +like this and then I have this function + + align:start position:0% +like this and then I have this function + + + align:start position:0% +like this and then I have this function +so this function here must + + align:start position:0% +so this function here must + + + align:start position:0% +so this function here must +be B of + + align:start position:0% +be B of + + + align:start position:0% +be B of +theta right so from this function + + align:start position:0% +theta right so from this function + + + align:start position:0% +theta right so from this function +exponential Theta I'm supposed to be + + align:start position:0% +exponential Theta I'm supposed to be + + + align:start position:0% +exponential Theta I'm supposed to be +able to read what the mean is + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +because since in this course I always + + align:start position:0% +because since in this course I always + + + align:start position:0% +because since in this course I always +know what the dispersion is I can + + align:start position:0% +know what the dispersion is I can + + + align:start position:0% +know what the dispersion is I can +actually always absorb it into Theta for + + align:start position:0% +actually always absorb it into Theta for + + + align:start position:0% +actually always absorb it into Theta for +one but here it's really of the form y + + align:start position:0% +one but here it's really of the form y + + + align:start position:0% +one but here it's really of the form y +times something divided by one right + + align:start position:0% + + + + align:start position:0% + +I mean I could have if it was like log + + align:start position:0% +I mean I could have if it was like log + + + align:start position:0% +I mean I could have if it was like log +of mu divided by five it would be the + + align:start position:0% +of mu divided by five it would be the + + + align:start position:0% +of mu divided by five it would be the +question of whether I want to call + + align:start position:0% +question of whether I want to call + + + align:start position:0% +question of whether I want to call +five five my dispersion or if I want to + + align:start position:0% +five five my dispersion or if I want to + + + align:start position:0% +five five my dispersion or if I want to +just like have it in there but if I know + + align:start position:0% +just like have it in there but if I know + + + align:start position:0% +just like have it in there but if I know +so + + align:start position:0% +so + + + align:start position:0% +so +usually so okay this makes no difference + + align:start position:0% +usually so okay this makes no difference + + + align:start position:0% +usually so okay this makes no difference +in practice but the real thing is when + + align:start position:0% +in practice but the real thing is when + + + align:start position:0% +in practice but the real thing is when +you it's never going to happen that this + + align:start position:0% +you it's never going to happen that this + + + align:start position:0% +you it's never going to happen that this +thing this dispersion is going to be an + + align:start position:0% +thing this dispersion is going to be an + + + align:start position:0% +thing this dispersion is going to be an +exact number if it's an actual numerical + + align:start position:0% +exact number if it's an actual numerical + + + align:start position:0% +exact number if it's an actual numerical +number this just means that this number + + align:start position:0% +number this just means that this number + + + align:start position:0% +number this just means that this number +should be absorb in the uh in the + + align:start position:0% +should be absorb in the uh in the + + + align:start position:0% +should be absorb in the uh in the +definition of theta but if it's + + align:start position:0% +definition of theta but if it's + + + align:start position:0% +definition of theta but if it's +something that is called Sigma say and I + + align:start position:0% +something that is called Sigma say and I + + + align:start position:0% +something that is called Sigma say and I +say and I will assume that Sigma is + + align:start position:0% +say and I will assume that Sigma is + + + align:start position:0% +say and I will assume that Sigma is +known then it's probably uh preferable + + align:start position:0% +known then it's probably uh preferable + + + align:start position:0% +known then it's probably uh preferable +to keep it in the dispersion so you can + + align:start position:0% +to keep it in the dispersion so you can + + + align:start position:0% +to keep it in the dispersion so you can +see that there's this parameter here + + align:start position:0% +see that there's this parameter here + + + align:start position:0% +see that there's this parameter here +that you can essentially play with okay + + align:start position:0% +that you can essentially play with okay + + + align:start position:0% +that you can essentially play with okay +that it doesn't make any difference when + + align:start position:0% +that it doesn't make any difference when + + + align:start position:0% +that it doesn't make any difference when +you know + + align:start position:0% +you know + + + align:start position:0% +you know +five okay so now uh what I have so okay + + align:start position:0% +five okay so now uh what I have so okay + + + align:start position:0% +five okay so now uh what I have so okay +so if I look at the + + align:start position:0% +so if I look at the + + + align:start position:0% +so if I look at the +expectation of some y so now I'm going + + align:start position:0% +expectation of some y so now I'm going + + + align:start position:0% +expectation of some y so now I'm going +to have Y which follows my P + + align:start position:0% +to have Y which follows my P + + + align:start position:0% +to have Y which follows my P +mu I'm going to take I'm going to look + + align:start position:0% +mu I'm going to take I'm going to look + + + align:start position:0% +mu I'm going to take I'm going to look +at the expectation and I know that the + + align:start position:0% +at the expectation and I know that the + + + align:start position:0% +at the expectation and I know that the +expectation is B + + align:start position:0% +expectation is B + + + align:start position:0% +expectation is B +Prime of theta + + align:start position:0% +Prime of theta + + + align:start position:0% +Prime of theta +right agreed that's what I just + + align:start position:0% +right agreed that's what I just + + + align:start position:0% +right agreed that's what I just +erased I + + align:start position:0% +erased I + + + align:start position:0% +erased I +think agreed with this the derivative + + align:start position:0% +think agreed with this the derivative + + + align:start position:0% +think agreed with this the derivative +all right so what is this well it's the + + align:start position:0% +all right so what is this well it's the + + + align:start position:0% +all right so what is this well it's the +derivative of e to the Theta which is e + + align:start position:0% +derivative of e to the Theta which is e + + + align:start position:0% +derivative of e to the Theta which is e +to the Theta which is + + align:start position:0% +to the Theta which is + + + align:start position:0% +to the Theta which is +Mu so my is parameterized by its mean I + + align:start position:0% +Mu so my is parameterized by its mean I + + + align:start position:0% +Mu so my is parameterized by its mean I +can also compute the + + align:start position:0% + + + + align:start position:0% + +variance which is equal to minus the + + align:start position:0% +variance which is equal to minus the + + + align:start position:0% +variance which is equal to minus the +second derivative of uh is it uh yeah no + + align:start position:0% +second derivative of uh is it uh yeah no + + + align:start position:0% +second derivative of uh is it uh yeah no +it's equal to the second derivative of + + align:start position:0% + + + + align:start position:0% + +B dispersion is equal to one again if I + + align:start position:0% +B dispersion is equal to one again if I + + + align:start position:0% +B dispersion is equal to one again if I +took uh fi elsewhere I would see it uh I + + align:start position:0% +took uh fi elsewhere I would see it uh I + + + align:start position:0% +took uh fi elsewhere I would see it uh I +would see it here as well right so if I + + align:start position:0% +would see it here as well right so if I + + + align:start position:0% +would see it here as well right so if I +just absorb five here I would see it + + align:start position:0% +just absorb five here I would see it + + + align:start position:0% +just absorb five here I would see it +divided here it would not make any + + align:start position:0% +divided here it would not make any + + + align:start position:0% +divided here it would not make any +difference and what is the second + + align:start position:0% +difference and what is the second + + + align:start position:0% +difference and what is the second +derivative of the + + align:start position:0% + + + + align:start position:0% + +exponential it's still the + + align:start position:0% +exponential it's still the + + + align:start position:0% +exponential it's still the +exponential so it's still equal to + + align:start position:0% +exponential so it's still equal to + + + align:start position:0% +exponential so it's still equal to +me + + align:start position:0% +me + + + align:start position:0% +me +okay so that certainly makes our uh life + + align:start position:0% +okay so that certainly makes our uh life + + + align:start position:0% +okay so that certainly makes our uh life +uh easier just uh one quick remark + + align:start position:0% + + + + align:start position:0% + +here's here's the B function I I giving + + align:start position:0% +here's here's the B function I I giving + + + align:start position:0% +here's here's the B function I I giving +you a problem can the B function of some + + align:start position:0% +you a problem can the B function of some + + + align:start position:0% +you a problem can the B function of some +uh this this function B can it ever be + + align:start position:0% +uh this this function B can it ever be + + + align:start position:0% +uh this this function B can it ever be +equal + + align:start position:0% + + + + align:start position:0% + +to log of + + align:start position:0% + + + + align:start position:0% + +theta who says yes + + align:start position:0% +theta who says yes + + + align:start position:0% +theta who says yes +who says + + align:start position:0% +who says + + + align:start position:0% +who says +no + + align:start position:0% + + + + align:start position:0% + +why yeah all right + + align:start position:0% +why yeah all right + + + align:start position:0% +why yeah all right +so what I've learned from this sort of + + align:start position:0% +so what I've learned from this sort of + + + align:start position:0% +so what I've learned from this sort of +completely analytic right so we just + + align:start position:0% +completely analytic right so we just + + + align:start position:0% +completely analytic right so we just +took derivatives and this thing just + + align:start position:0% +took derivatives and this thing just + + + align:start position:0% +took derivatives and this thing just +happened right this thing actually + + align:start position:0% +happened right this thing actually + + + align:start position:0% +happened right this thing actually +allowed us to relate the second + + align:start position:0% +allowed us to relate the second + + + align:start position:0% +allowed us to relate the second +derivative of B to the variance and one + + align:start position:0% +derivative of B to the variance and one + + + align:start position:0% +derivative of B to the variance and one +thing that we know about a variance is + + align:start position:0% +thing that we know about a variance is + + + align:start position:0% +thing that we know about a variance is +that this is non- negative and in + + align:start position:0% +that this is non- negative and in + + + align:start position:0% +that this is non- negative and in +particular it's always positive right I + + align:start position:0% +particular it's always positive right I + + + align:start position:0% +particular it's always positive right I +mean if I give you an expon a canonical + + align:start position:0% +mean if I give you an expon a canonical + + + align:start position:0% +mean if I give you an expon a canonical +exponential family that has zero + + align:start position:0% +exponential family that has zero + + + align:start position:0% +exponential family that has zero +variance trust me you will see it right + + align:start position:0% +variance trust me you will see it right + + + align:start position:0% +variance trust me you will see it right +I mean that means that this thing is not + + align:start position:0% +I mean that means that this thing is not + + + align:start position:0% +I mean that means that this thing is not +going to look like something that's + + align:start position:0% +going to look like something that's + + + align:start position:0% +going to look like something that's +finite it means it's going to have a + + align:start position:0% +finite it means it's going to have a + + + align:start position:0% +finite it means it's going to have a +point mass is going to take value + + align:start position:0% +point mass is going to take value + + + align:start position:0% +point mass is going to take value +Infinity at one point so this will + + align:start position:0% +Infinity at one point so this will + + + align:start position:0% +Infinity at one point so this will +basically never happen this thing is + + align:start position:0% +basically never happen this thing is + + + align:start position:0% +basically never happen this thing is +actually strictly positive which means + + align:start position:0% +actually strictly positive which means + + + align:start position:0% +actually strictly positive which means +that this thing is always like strictly + + align:start position:0% +that this thing is always like strictly + + + align:start position:0% +that this thing is always like strictly +concave it means that the second + + align:start position:0% +concave it means that the second + + + align:start position:0% +concave it means that the second +derivative of this function B has to be + + align:start position:0% +derivative of this function B has to be + + + align:start position:0% +derivative of this function B has to be +strictly uh positive and so that the + + align:start position:0% +strictly uh positive and so that the + + + align:start position:0% +strictly uh positive and so that the +function is convex okay so this is + + align:start position:0% +function is convex okay so this is + + + align:start position:0% +function is convex okay so this is +concave so this is definitely not + + align:start position:0% +concave so this is definitely not + + + align:start position:0% +concave so this is definitely not +working I need to have something that + + align:start position:0% +working I need to have something that + + + align:start position:0% +working I need to have something that +looks like this when I talk about my + + align:start position:0% +looks like this when I talk about my + + + align:start position:0% +looks like this when I talk about my +be okay so Theta squared uh we'll see a + + align:start position:0% +be okay so Theta squared uh we'll see a + + + align:start position:0% +be okay so Theta squared uh we'll see a +bunch exponential Theta you know there's + + align:start position:0% +bunch exponential Theta you know there's + + + align:start position:0% +bunch exponential Theta you know there's +a bunch of them but if you start writing + + align:start position:0% +a bunch of them but if you start writing + + + align:start position:0% +a bunch of them but if you start writing +something and you find B you know try to + + align:start position:0% +something and you find B you know try to + + + align:start position:0% +something and you find B you know try to +think of the plot of B in your mind and + + align:start position:0% +think of the plot of B in your mind and + + + align:start position:0% +think of the plot of B in your mind and +you find that b looks like it's going to + + align:start position:0% +you find that b looks like it's going to + + + align:start position:0% +you find that b looks like it's going to +be concave you've been you've made a + + align:start position:0% +be concave you've been you've made a + + + align:start position:0% +be concave you've been you've made a +sign mistake somewhere + + align:start position:0% + + + + align:start position:0% + +all right so we've done a pretty big + + align:start position:0% +all right so we've done a pretty big + + + align:start position:0% +all right so we've done a pretty big +parenthesis to try to characterize what + + align:start position:0% +parenthesis to try to characterize what + + + align:start position:0% +parenthesis to try to characterize what +the distribution of Y was going to be + + align:start position:0% +the distribution of Y was going to be + + + align:start position:0% +the distribution of Y was going to be +right we wanted to extend from say gaan + + align:start position:0% +right we wanted to extend from say gaan + + + align:start position:0% +right we wanted to extend from say gaan +to something else and uh but when we're + + align:start position:0% +to something else and uh but when we're + + + align:start position:0% +to something else and uh but when we're +doing regression which means the + + align:start position:0% +doing regression which means the + + + align:start position:0% +doing regression which means the +generalized linear models we are not + + align:start position:0% +generalized linear models we are not + + + align:start position:0% +generalized linear models we are not +interested in the distribution of Y but + + align:start position:0% +interested in the distribution of Y but + + + align:start position:0% +interested in the distribution of Y but +really the conditional distribution of Y + + align:start position:0% +really the conditional distribution of Y + + + align:start position:0% +really the conditional distribution of Y +given X so I need now to sort of couple + + align:start position:0% +given X so I need now to sort of couple + + + align:start position:0% +given X so I need now to sort of couple +those back together all right so what I + + align:start position:0% +those back together all right so what I + + + align:start position:0% +those back together all right so what I +know is that + + align:start position:0% +know is that + + + align:start position:0% +know is that +this say mu in this case which is the + + align:start position:0% +this say mu in this case which is the + + + align:start position:0% +this say mu in this case which is the +expectation what I want to say is that + + align:start position:0% +expectation what I want to say is that + + + align:start position:0% +expectation what I want to say is that +the conditional expectation of Y uh uh + + align:start position:0% +the conditional expectation of Y uh uh + + + align:start position:0% +the conditional expectation of Y uh uh +given mu sorry the conditional + + align:start position:0% +given mu sorry the conditional + + + align:start position:0% +given mu sorry the conditional +expectation of Y given + + align:start position:0% + + + + align:start position:0% + +X this is some mu of X right and when we + + align:start position:0% +X this is some mu of X right and when we + + + align:start position:0% +X this is some mu of X right and when we +did linear models we said well this + + align:start position:0% +did linear models we said well this + + + align:start position:0% +did linear models we said well this +thing was some X transpose beta for + + align:start position:0% +thing was some X transpose beta for + + + align:start position:0% +thing was some X transpose beta for +linear + + align:start position:0% + + + + align:start position:0% + +models and the whole premise of this + + align:start position:0% +models and the whole premise of this + + + align:start position:0% +models and the whole premise of this +chapter is to say well this might make + + align:start position:0% +chapter is to say well this might make + + + align:start position:0% +chapter is to say well this might make +no sense because X transpose beta can + + align:start position:0% +no sense because X transpose beta can + + + align:start position:0% +no sense because X transpose beta can +take the entire range of real values + + align:start position:0% +take the entire range of real values + + + align:start position:0% +take the entire range of real values +whereas this mu can take only a partial + + align:start position:0% +whereas this mu can take only a partial + + + align:start position:0% +whereas this mu can take only a partial +range so even if you actually focus on + + align:start position:0% +range so even if you actually focus on + + + align:start position:0% +range so even if you actually focus on +the uh on the pon for example we know + + align:start position:0% +the uh on the pon for example we know + + + align:start position:0% +the uh on the pon for example we know +that the expectation of a Pon has to be + + align:start position:0% +that the expectation of a Pon has to be + + + align:start position:0% +that the expectation of a Pon has to be +a non- negative number actually positive + + align:start position:0% +a non- negative number actually positive + + + align:start position:0% +a non- negative number actually positive +number as soon as you have a little bit + + align:start position:0% +number as soon as you have a little bit + + + align:start position:0% +number as soon as you have a little bit +of variance right it's mu itself mu is a + + align:start position:0% +of variance right it's mu itself mu is a + + + align:start position:0% +of variance right it's mu itself mu is a +positive number and so it's not going to + + align:start position:0% +positive number and so it's not going to + + + align:start position:0% +positive number and so it's not going to +make any sense to assume that mu of X is + + align:start position:0% +make any sense to assume that mu of X is + + + align:start position:0% +make any sense to assume that mu of X is +equal to X transpose beta because you + + align:start position:0% +equal to X transpose beta because you + + + align:start position:0% +equal to X transpose beta because you +might find some x's for which this value + + align:start position:0% +might find some x's for which this value + + + align:start position:0% +might find some x's for which this value +ends up being negative and so we're + + align:start position:0% +ends up being negative and so we're + + + align:start position:0% +ends up being negative and so we're +going to need what we call the link + + align:start position:0% +going to need what we call the link + + + align:start position:0% +going to need what we call the link +function that relates that transforms mu + + align:start position:0% +function that relates that transforms mu + + + align:start position:0% +function that relates that transforms mu +Maps it onto the real line so that you + + align:start position:0% +Maps it onto the real line so that you + + + align:start position:0% +Maps it onto the real line so that you +can now express it of the form X + + align:start position:0% +can now express it of the form X + + + align:start position:0% +can now express it of the form X +transpose beta all right so we're going + + align:start position:0% +transpose beta all right so we're going + + + align:start position:0% +transpose beta all right so we're going +to take um not this but we're going to + + align:start position:0% +to take um not this but we're going to + + + align:start position:0% +to take um not this but we're going to +assume that g of mu of + + align:start position:0% +assume that g of mu of + + + align:start position:0% +assume that g of mu of +X is now equal to Xpose beta and that's + + align:start position:0% +X is now equal to Xpose beta and that's + + + align:start position:0% +X is now equal to Xpose beta and that's +the generalized linear models right + + align:start position:0% + + + + align:start position:0% + +okay so as I + + align:start position:0% +okay so as I + + + align:start position:0% +okay so as I +said it's kind of weird to + + align:start position:0% +said it's kind of weird to + + + align:start position:0% +said it's kind of weird to +transform X transpose beta a mu to make + + align:start position:0% +transform X transpose beta a mu to make + + + align:start position:0% +transform X transpose beta a mu to make +it take the real line it feels like at + + align:start position:0% +it take the real line it feels like at + + + align:start position:0% +it take the real line it feels like at +least to me it feels a bit more natural + + align:start position:0% +least to me it feels a bit more natural + + + align:start position:0% +least to me it feels a bit more natural +to take X transpose beta and make it fit + + align:start position:0% +to take X transpose beta and make it fit + + + align:start position:0% +to take X transpose beta and make it fit +to the particular distribution that I + + align:start position:0% +to the particular distribution that I + + + align:start position:0% +to the particular distribution that I +want and so I'm goingon to want to talk + + align:start position:0% +want and so I'm goingon to want to talk + + + align:start position:0% +want and so I'm goingon to want to talk +about G and G inverse at the same time + + align:start position:0% +about G and G inverse at the same time + + + align:start position:0% +about G and G inverse at the same time +so I'm gonna actually take always G so G + + align:start position:0% +so I'm gonna actually take always G so G + + + align:start position:0% +so I'm gonna actually take always G so G +is my link + + align:start position:0% + + + + align:start position:0% + +function and I'm going to want G to be + + align:start position:0% +function and I'm going to want G to be + + + align:start position:0% +function and I'm going to want G to be +uh continuously + + align:start position:0% + + + + align:start position:0% + +differentiable okay let's say that it + + align:start position:0% +differentiable okay let's say that it + + + align:start position:0% +differentiable okay let's say that it +has a derivative and its derivative is + + align:start position:0% +has a derivative and its derivative is + + + align:start position:0% +has a derivative and its derivative is +uh is continuous and I'm going to want + + align:start position:0% +uh is continuous and I'm going to want + + + align:start position:0% +uh is continuous and I'm going to want +uh uh G to be strictly increased + + align:start position:0% + + + + align:start position:0% + +okay and that actually implies that g + + align:start position:0% +okay and that actually implies that g + + + align:start position:0% +okay and that actually implies that g +inverse exists actually that's not true + + align:start position:0% +inverse exists actually that's not true + + + align:start position:0% +inverse exists actually that's not true +um what I'm also going to + + align:start position:0% +um what I'm also going to + + + align:start position:0% +um what I'm also going to +want is + + align:start position:0% +want is + + + align:start position:0% +want is +that + + align:start position:0% +that + + + align:start position:0% +that +g of + + align:start position:0% +g of + + + align:start position:0% +g of +mu uh + + align:start position:0% +mu uh + + + align:start position:0% +mu uh +spans uh okay how do I do this um uh + + align:start position:0% +spans uh okay how do I do this um uh + + + align:start position:0% +spans uh okay how do I do this um uh +well + + align:start position:0% + + + + align:start position:0% + +okay so I want that g as I range for all + + align:start position:0% +okay so I want that g as I range for all + + + align:start position:0% +okay so I want that g as I range for all +possible values of mu whether they're + + align:start position:0% +possible values of mu whether they're + + + align:start position:0% +possible values of mu whether they're +all positive values or whether they're + + align:start position:0% +all positive values or whether they're + + + align:start position:0% +all positive values or whether they're +values that are limited between the + + align:start position:0% +values that are limited between the + + + align:start position:0% +values that are limited between the +interval Z one I want those to span the + + align:start position:0% +interval Z one I want those to span the + + + align:start position:0% +interval Z one I want those to span the +entire real line so that when I want to + + align:start position:0% +entire real line so that when I want to + + + align:start position:0% +entire real line so that when I want to +talk about G inverse is defin over the + + align:start position:0% +talk about G inverse is defin over the + + + align:start position:0% +talk about G inverse is defin over the +entire real line I know where I started + + align:start position:0% +entire real line I know where I started + + + align:start position:0% +entire real line I know where I started +okay so uh uh uh this implies that g + + align:start position:0% +okay so uh uh uh this implies that g + + + align:start position:0% +okay so uh uh uh this implies that g +inverse exists + + align:start position:0% + + + + align:start position:0% + +what else does it imply about G + + align:start position:0% + + + + align:start position:0% + +inverse so for a function to be + + align:start position:0% +inverse so for a function to be + + + align:start position:0% +inverse so for a function to be +invertible only I only need for it to be + + align:start position:0% +invertible only I only need for it to be + + + align:start position:0% +invertible only I only need for it to be +strictly monotone right I don't need it + + align:start position:0% +strictly monotone right I don't need it + + + align:start position:0% +strictly monotone right I don't need it +to be strictly increasing so in + + align:start position:0% +to be strictly increasing so in + + + align:start position:0% +to be strictly increasing so in +particular the fact that I picked + + align:start position:0% +particular the fact that I picked + + + align:start position:0% +particular the fact that I picked +increasing implies that this guy is + + align:start position:0% +increasing implies that this guy is + + + align:start position:0% +increasing implies that this guy is +actually + + align:start position:0% +actually + + + align:start position:0% +actually +increasing + + align:start position:0% +increasing + + + align:start position:0% +increasing +okay uh that's the image + + align:start position:0% + + + + align:start position:0% + +okay so this is my uh link function and + + align:start position:0% +okay so this is my uh link function and + + + align:start position:0% +okay so this is my uh link function and +this slide is just telling me I want my + + align:start position:0% +this slide is just telling me I want my + + + align:start position:0% +this slide is just telling me I want my +function to be invertible so I can talk + + align:start position:0% +function to be invertible so I can talk + + + align:start position:0% +function to be invertible so I can talk +about G inverse I'm going to switch + + align:start position:0% +about G inverse I'm going to switch + + + align:start position:0% +about G inverse I'm going to switch +between the two so what link functions + + align:start position:0% +between the two so what link functions + + + align:start position:0% +between the two so what link functions +am I going to get right so for linear + + align:start position:0% +am I going to get right so for linear + + + align:start position:0% +am I going to get right so for linear +models we just said there's no link + + align:start position:0% +models we just said there's no link + + + align:start position:0% +models we just said there's no link +function which is the same as saying + + align:start position:0% +function which is the same as saying + + + align:start position:0% +function which is the same as saying +that the link function is identity which + + align:start position:0% +that the link function is identity which + + + align:start position:0% +that the link function is identity which +certainly satisfies all these conditions + + align:start position:0% +certainly satisfies all these conditions + + + align:start position:0% +certainly satisfies all these conditions +it's invertible it has all these nice + + align:start position:0% +it's invertible it has all these nice + + + align:start position:0% +it's invertible it has all these nice +properties but you know might as well + + align:start position:0% +properties but you know might as well + + + align:start position:0% +properties but you know might as well +not talk about it for Pon data when we + + align:start position:0% +not talk about it for Pon data when we + + + align:start position:0% +not talk about it for Pon data when we +assume that the conditional distribution + + align:start position:0% +assume that the conditional distribution + + + align:start position:0% +assume that the conditional distribution +of Y given X is + + align:start position:0% +of Y given X is + + + align:start position:0% +of Y given X is +Pon then mu as I just said is required + + align:start position:0% +Pon then mu as I just said is required + + + align:start position:0% +Pon then mu as I just said is required +to be positive so I need a g that goes + + align:start position:0% +to be positive so I need a g that goes + + + align:start position:0% +to be positive so I need a g that goes +from the + + align:start position:0% +from the + + + align:start position:0% +from the +interval zero Infinity to the entire + + align:start position:0% +interval zero Infinity to the entire + + + align:start position:0% +interval zero Infinity to the entire +real line I need a function that starts + + align:start position:0% +real line I need a function that starts + + + align:start position:0% +real line I need a function that starts +from one end and just you know takes not + + align:start position:0% +from one end and just you know takes not + + + align:start position:0% +from one end and just you know takes not +only the the positive values are split + + align:start position:0% +only the the positive values are split + + + align:start position:0% +only the the positive values are split +between positive and negative values and + + align:start position:0% +between positive and negative values and + + + align:start position:0% +between positive and negative values and +here for example I could take the log + + align:start position:0% +here for example I could take the log + + + align:start position:0% +here for example I could take the log +link right so the log + + align:start position:0% +link right so the log + + + align:start position:0% +link right so the log +is defined on this entire + + align:start position:0% +is defined on this entire + + + align:start position:0% +is defined on this entire +interval and as I range from zero to + + align:start position:0% +interval and as I range from zero to + + + align:start position:0% +interval and as I range from zero to +plus infinity the log is ranging from + + align:start position:0% +plus infinity the log is ranging from + + + align:start position:0% +plus infinity the log is ranging from +negative Infinity to plus infinity + + align:start position:0% +negative Infinity to plus infinity + + + align:start position:0% +negative Infinity to plus infinity +right so you know you can probably think + + align:start position:0% +right so you know you can probably think + + + align:start position:0% +right so you know you can probably think +of other functions that do that like two + + align:start position:0% +of other functions that do that like two + + + align:start position:0% +of other functions that do that like two +times log that's another one right but + + align:start position:0% +times log that's another one right but + + + align:start position:0% +times log that's another one right but +there's many other you can think of and + + align:start position:0% +there's many other you can think of and + + + align:start position:0% +there's many other you can think of and +uh but let's say the log is one of them + + align:start position:0% +uh but let's say the log is one of them + + + align:start position:0% +uh but let's say the log is one of them +that you might want to think + + align:start position:0% +that you might want to think + + + align:start position:0% +that you might want to think +about + + align:start position:0% +about + + + align:start position:0% +about +um then um + + align:start position:0% +um then um + + + align:start position:0% +um then um +there's uh um and we'll see that this is + + align:start position:0% +there's uh um and we'll see that this is + + + align:start position:0% +there's uh um and we'll see that this is +actually I mean it is a natural one in + + align:start position:0% +actually I mean it is a natural one in + + + align:start position:0% +actually I mean it is a natural one in +the sense that it's one of the first + + align:start position:0% +the sense that it's one of the first + + + align:start position:0% +the sense that it's one of the first +function we can think of it we'll see + + align:start position:0% +function we can think of it we'll see + + + align:start position:0% +function we can think of it we'll see +also that it has another canonical + + align:start position:0% +also that it has another canonical + + + align:start position:0% +also that it has another canonical +property that makes it a Natural Choice + + align:start position:0% +property that makes it a Natural Choice + + + align:start position:0% +property that makes it a Natural Choice +uh the other one is uh the other example + + align:start position:0% +uh the other one is uh the other example + + + align:start position:0% +uh the other one is uh the other example +where we had a even stronger condition + + align:start position:0% +where we had a even stronger condition + + + align:start position:0% +where we had a even stronger condition +on what mu could be mu could only be a + + align:start position:0% +on what mu could be mu could only be a + + + align:start position:0% +on what mu could be mu could only be a +number between zero and one that was the + + align:start position:0% +number between zero and one that was the + + + align:start position:0% +number between zero and one that was the +probability of success of a coin flip + + align:start position:0% +probability of success of a coin flip + + + align:start position:0% +probability of success of a coin flip +right the probability of success of a + + align:start position:0% +right the probability of success of a + + + align:start position:0% +right the probability of success of a +burnly random variable and now I need G + + align:start position:0% +burnly random variable and now I need G + + + align:start position:0% +burnly random variable and now I need G +to map zero one to the entire real line + + align:start position:0% +to map zero one to the entire real line + + + align:start position:0% +to map zero one to the entire real line +and so here are a bunch of uh of things + + align:start position:0% +and so here are a bunch of uh of things + + + align:start position:0% +and so here are a bunch of uh of things +that you can come up with because you + + align:start position:0% +that you can come up with because you + + + align:start position:0% +that you can come up with because you +know now you start to have maybe I mean + + align:start position:0% +know now you start to have maybe I mean + + + align:start position:0% +know now you start to have maybe I mean +you know I claim I will soon claim that + + align:start position:0% +you know I claim I will soon claim that + + + align:start position:0% +you know I claim I will soon claim that +this one log of mu divided by one minus + + align:start position:0% +this one log of mu divided by one minus + + + align:start position:0% +this one log of mu divided by one minus +mu is the most natural one but maybe you + + align:start position:0% +mu is the most natural one but maybe you + + + align:start position:0% +mu is the most natural one but maybe you +know if you had never thought of this + + align:start position:0% +know if you had never thought of this + + + align:start position:0% +know if you had never thought of this +that might not be the most the first + + align:start position:0% +that might not be the most the first + + + align:start position:0% +that might not be the most the first +function you would come up with right uh + + align:start position:0% +function you would come up with right uh + + + align:start position:0% +function you would come up with right uh +you mentioned trigonometric functions + + align:start position:0% +you mentioned trigonometric functions + + + align:start position:0% +you mentioned trigonometric functions +for example uh so you know maybe you can + + align:start position:0% +for example uh so you know maybe you can + + + align:start position:0% +for example uh so you know maybe you can +come up with something that like you + + align:start position:0% +come up with something that like you + + + align:start position:0% +come up with something that like you +know comes from I don't know hyper um uh + + align:start position:0% +know comes from I don't know hyper um uh + + + align:start position:0% +know comes from I don't know hyper um uh +hyperbolic trigonometry or something so + + align:start position:0% +hyperbolic trigonometry or something so + + + align:start position:0% +hyperbolic trigonometry or something so +what does this function do well we'll + + align:start position:0% +what does this function do well we'll + + + align:start position:0% +what does this function do well we'll +see a picture but this function does map + + align:start position:0% +see a picture but this function does map + + + align:start position:0% +see a picture but this function does map +the interval 01 to the entire real line + + align:start position:0% +the interval 01 to the entire real line + + + align:start position:0% +the interval 01 to the entire real line +we also discussed the fact that if we + + align:start position:0% +we also discussed the fact that if we + + + align:start position:0% +we also discussed the fact that if we +think + + align:start position:0% +think + + + align:start position:0% +think +reciprocally uh well a function uh what + + align:start position:0% +reciprocally uh well a function uh what + + + align:start position:0% +reciprocally uh well a function uh what +I want if I want to think about G + + align:start position:0% +I want if I want to think about G + + + align:start position:0% +I want if I want to think about G +inverse I want a function that Maps the + + align:start position:0% +inverse I want a function that Maps the + + + align:start position:0% +inverse I want a function that Maps the +entire real line into the unit interval + + align:start position:0% +entire real line into the unit interval + + + align:start position:0% +entire real line into the unit interval +and as we said if I'm not a very + + align:start position:0% +and as we said if I'm not a very + + + align:start position:0% +and as we said if I'm not a very +creative statistici or problemist I can + + align:start position:0% +creative statistici or problemist I can + + + align:start position:0% +creative statistici or problemist I can +just pick my favorites continuous + + align:start position:0% +just pick my favorites continuous + + + align:start position:0% +just pick my favorites continuous +strictly increasing uh cumulative + + align:start position:0% +strictly increasing uh cumulative + + + align:start position:0% +strictly increasing uh cumulative +distribution function which as we know + + align:start position:0% +distribution function which as we know + + + align:start position:0% +distribution function which as we know +will arise as soon as I have a density + + align:start position:0% +will arise as soon as I have a density + + + align:start position:0% +will arise as soon as I have a density +that has support on the entire real line + + align:start position:0% +that has support on the entire real line + + + align:start position:0% +that has support on the entire real line +right if I have support everywhere then + + align:start position:0% +right if I have support everywhere then + + + align:start position:0% +right if I have support everywhere then +it means that my um + + align:start position:0% +it means that my um + + + align:start position:0% +it means that my um +uh by meaning that the fun the density + + align:start position:0% +uh by meaning that the fun the density + + + align:start position:0% +uh by meaning that the fun the density +is strictly positive everywhere then it + + align:start position:0% +is strictly positive everywhere then it + + + align:start position:0% +is strictly positive everywhere then it +means that my uh uh communative + + align:start position:0% +means that my uh uh communative + + + align:start position:0% +means that my uh uh communative +distribution function has to be strictly + + align:start position:0% +distribution function has to be strictly + + + align:start position:0% +distribution function has to be strictly +increasing and of course it has to go + + align:start position:0% +increasing and of course it has to go + + + align:start position:0% +increasing and of course it has to go +from zero to one because that's just + + align:start position:0% +from zero to one because that's just + + + align:start position:0% +from zero to one because that's just +nature of those things and so for + + align:start position:0% +nature of those things and so for + + + align:start position:0% +nature of those things and so for +example I can take the gussan that's one + + align:start position:0% +example I can take the gussan that's one + + + align:start position:0% +example I can take the gussan that's one +such function but I could also take you + + align:start position:0% +such function but I could also take you + + + align:start position:0% +such function but I could also take you +know the double exponential that looks + + align:start position:0% +know the double exponential that looks + + + align:start position:0% +know the double exponential that looks +like an exponential on one end and an + + align:start position:0% +like an exponential on one end and an + + + align:start position:0% +like an exponential on one end and an +exponential on the other end and uh uh + + align:start position:0% +exponential on the other end and uh uh + + + align:start position:0% +exponential on the other end and uh uh +uh basically if you take uh something + + align:start position:0% +uh basically if you take uh something + + + align:start position:0% +uh basically if you take uh something +which is called uh which if you take + + align:start position:0% +which is called uh which if you take + + + align:start position:0% +which is called uh which if you take +capital F which is the um gaussian + + align:start position:0% +capital F which is the um gaussian + + + align:start position:0% +capital F which is the um gaussian +standard gaussian Cula distribution + + align:start position:0% +standard gaussian Cula distribution + + + align:start position:0% +standard gaussian Cula distribution +function it does work for you and you + + align:start position:0% +function it does work for you and you + + + align:start position:0% +function it does work for you and you +can take its inverse and in this case we + + align:start position:0% +can take its inverse and in this case we + + + align:start position:0% +can take its inverse and in this case we +don't talk about so this guy is called + + align:start position:0% +don't talk about so this guy is called + + + align:start position:0% +don't talk about so this guy is called +logit or logit and this guy is called + + align:start position:0% +logit or logit and this guy is called + + + align:start position:0% +logit or logit and this guy is called +proit and you see it usually every time + + align:start position:0% +proit and you see it usually every time + + + align:start position:0% +proit and you see it usually every time +you have a package on uh a Iz in your + + align:start position:0% +you have a package on uh a Iz in your + + + align:start position:0% +you have a package on uh a Iz in your +models uh you're trying to implement you + + align:start position:0% +models uh you're trying to implement you + + + align:start position:0% +models uh you're trying to implement you +have this choice and for what's called + + align:start position:0% +have this choice and for what's called + + + align:start position:0% +have this choice and for what's called +logistic regression so it's kind of + + align:start position:0% +logistic regression so it's kind of + + + align:start position:0% +logistic regression so it's kind of +funny that it's called logistic + + align:start position:0% +funny that it's called logistic + + + align:start position:0% +funny that it's called logistic +regression but you can actually use the + + align:start position:0% +regression but you can actually use the + + + align:start position:0% +regression but you can actually use the +proit link which in this case is get I + + align:start position:0% +proit link which in this case is get I + + + align:start position:0% +proit link which in this case is get I +guess is called proit regression but + + align:start position:0% +guess is called proit regression but + + + align:start position:0% +guess is called proit regression but +those things are essentially equivalent + + align:start position:0% +those things are essentially equivalent + + + align:start position:0% +those things are essentially equivalent +and it's really a matter of taste okay + + align:start position:0% +and it's really a matter of taste okay + + + align:start position:0% +and it's really a matter of taste okay +maybe of community some communities + + align:start position:0% +maybe of community some communities + + + align:start position:0% +maybe of community some communities +might prefer one or the other we'll see + + align:start position:0% +might prefer one or the other we'll see + + + align:start position:0% +might prefer one or the other we'll see +that again as I claimed before the + + align:start position:0% +that again as I claimed before the + + + align:start position:0% +that again as I claimed before the +logistic one the lit one uh is uh has a + + align:start position:0% +logistic one the lit one uh is uh has a + + + align:start position:0% +logistic one the lit one uh is uh has a +slightly more compelling argument for + + align:start position:0% +slightly more compelling argument for + + + align:start position:0% +slightly more compelling argument for +its reason to exist I guess this one the + + align:start position:0% +its reason to exist I guess this one the + + + align:start position:0% +its reason to exist I guess this one the +compelling argument is that is involved + + align:start position:0% +compelling argument is that is involved + + + align:start position:0% +compelling argument is that is involved +the central uh the standard gaussian + + align:start position:0% +the central uh the standard gaussian + + + align:start position:0% +the central uh the standard gaussian +which of course is something that should + + align:start position:0% +which of course is something that should + + + align:start position:0% +which of course is something that should +show up everywhere and then you can + + align:start position:0% +show up everywhere and then you can + + + align:start position:0% +show up everywhere and then you can +think about crazy stuff okay something + + align:start position:0% +think about crazy stuff okay something + + + align:start position:0% +think about crazy stuff okay something +that even even crazy gets a name uh + + align:start position:0% +that even even crazy gets a name uh + + + align:start position:0% +that even even crazy gets a name uh +complimentary log log which is the log + + align:start position:0% +complimentary log log which is the log + + + align:start position:0% +complimentary log log which is the log +of minus log one minus okay you know why + + align:start position:0% +of minus log one minus okay you know why + + + align:start position:0% +of minus log one minus okay you know why +not + + align:start position:0% +not + + + align:start position:0% +not +um so I guess you can iterate that thing + + align:start position:0% +um so I guess you can iterate that thing + + + align:start position:0% +um so I guess you can iterate that thing +right you can just do put a One log one + + align:start position:0% +right you can just do put a One log one + + + align:start position:0% +right you can just do put a One log one +minus in front of this thing it's still + + align:start position:0% +minus in front of this thing it's still + + + align:start position:0% +minus in front of this thing it's still +going to go all right so + + align:start position:0% + + + + align:start position:0% + +um that's not true I have to put a minus + + align:start position:0% +um that's not true I have to put a minus + + + align:start position:0% +um that's not true I have to put a minus +and take another + + align:start position:0% +and take another + + + align:start position:0% +and take another +another no that's not true okay so um + + align:start position:0% +another no that's not true okay so um + + + align:start position:0% +another no that's not true okay so um +okay so you can think of whatever you + + align:start position:0% +okay so you can think of whatever you + + + align:start position:0% +okay so you can think of whatever you +want but now um uh you can actually so I + + align:start position:0% +want but now um uh you can actually so I + + + align:start position:0% +want but now um uh you can actually so I +I'll show so I claim that the lit link + + align:start position:0% +I'll show so I claim that the lit link + + + align:start position:0% +I'll show so I claim that the lit link +is the Natural Choice so here's a + + align:start position:0% +is the Natural Choice so here's a + + + align:start position:0% +is the Natural Choice so here's a +picture I should have actually plotted + + align:start position:0% +picture I should have actually plotted + + + align:start position:0% +picture I should have actually plotted +the other one uh so we can actually + + align:start position:0% +the other one uh so we can actually + + + align:start position:0% +the other one uh so we can actually +compare it uh to be fair I don't even + + align:start position:0% +compare it uh to be fair I don't even + + + align:start position:0% +compare it uh to be fair I don't even +remember how it would actually fit in + + align:start position:0% +remember how it would actually fit in + + + align:start position:0% +remember how it would actually fit in +those uh in those two functions so the + + align:start position:0% +those uh in those two functions so the + + + align:start position:0% +those uh in those two functions so the +blue one which is this one for those of + + align:start position:0% +blue one which is this one for those of + + + align:start position:0% +blue one which is this one for those of +you who don't see the difference between + + align:start position:0% +you who don't see the difference between + + + align:start position:0% +you who don't see the difference between +blue and red sorry about that uh so this + + align:start position:0% +blue and red sorry about that uh so this + + + align:start position:0% +blue and red sorry about that uh so this +is the so the blue one is the uh + + align:start position:0% +is the so the blue one is the uh + + + align:start position:0% +is the so the blue one is the uh +logistic one so that's okay so this guy + + align:start position:0% +logistic one so that's okay so this guy + + + align:start position:0% +logistic one so that's okay so this guy +is the function that does e todx over 1 + + align:start position:0% +is the function that does e todx over 1 + + + align:start position:0% +is the function that does e todx over 1 +plus e todx as you can see this is a + + align:start position:0% +plus e todx as you can see this is a + + + align:start position:0% +plus e todx as you can see this is a +function that's supposed to map the + + align:start position:0% +function that's supposed to map the + + + align:start position:0% +function that's supposed to map the +entire real line into the interval 01 + + align:start position:0% +entire real line into the interval 01 + + + align:start position:0% +entire real line into the interval 01 +okay so that's supposed to be the in + + align:start position:0% +okay so that's supposed to be the in + + + align:start position:0% +okay so that's supposed to be the in +inverse of your function and I claim + + align:start position:0% +inverse of your function and I claim + + + align:start position:0% +inverse of your function and I claim +that this is the inverse of the logistic + + align:start position:0% +that this is the inverse of the logistic + + + align:start position:0% +that this is the inverse of the logistic +of the late function and the blue one + + align:start position:0% +of the late function and the blue one + + + align:start position:0% +of the late function and the blue one +well this is the gon CDF so you know + + align:start position:0% +well this is the gon CDF so you know + + + align:start position:0% +well this is the gon CDF so you know +it's clearly the inverse of the inverse + + align:start position:0% +it's clearly the inverse of the inverse + + + align:start position:0% +it's clearly the inverse of the inverse +of the ga and CDF and that's the red one + + align:start position:0% +of the ga and CDF and that's the red one + + + align:start position:0% +of the ga and CDF and that's the red one +that's the one that goes here so one of + + align:start position:0% +that's the one that goes here so one of + + + align:start position:0% +that's the one that goes here so one of +the thing uh that I would guess that the + + align:start position:0% +the thing uh that I would guess that the + + + align:start position:0% +the thing uh that I would guess that the +complementary log log is something + + align:start position:0% +complementary log log is something + + + align:start position:0% +complementary log log is something +that's probably going above here and for + + align:start position:0% +that's probably going above here and for + + + align:start position:0% +that's probably going above here and for +which the slope is actually even a + + align:start position:0% +which the slope is actually even a + + + align:start position:0% +which the slope is actually even a +little flatter as you cross uh zero okay + + align:start position:0% +little flatter as you cross uh zero okay + + + align:start position:0% +little flatter as you cross uh zero okay +um so okay so of course this is not our + + align:start position:0% +um so okay so of course this is not our + + + align:start position:0% +um so okay so of course this is not our +link functions these are the inverse of + + align:start position:0% +link functions these are the inverse of + + + align:start position:0% +link functions these are the inverse of +our link function so what do they look + + align:start position:0% +our link function so what do they look + + + align:start position:0% +our link function so what do they look +like when I actually basically flip my + + align:start position:0% +like when I actually basically flip my + + + align:start position:0% +like when I actually basically flip my +uh my thing like this so this is what I + + align:start position:0% +uh my thing like this so this is what I + + + align:start position:0% +uh my thing like this so this is what I +see okay and so I can see that in blue + + align:start position:0% +see okay and so I can see that in blue + + + align:start position:0% +see okay and so I can see that in blue +this is my logistic link so I have it + + align:start position:0% +this is my logistic link so I have it + + + align:start position:0% +this is my logistic link so I have it +crosses zero with a slightly faster rate + + align:start position:0% +crosses zero with a slightly faster rate + + + align:start position:0% +crosses zero with a slightly faster rate +remember our hope if we could use the + + align:start position:0% +remember our hope if we could use the + + + align:start position:0% +remember our hope if we could use the +identity that would be very nice to us + + align:start position:0% +identity that would be very nice to us + + + align:start position:0% +identity that would be very nice to us +right we would just want to take the + + align:start position:0% +right we would just want to take the + + + align:start position:0% +right we would just want to take the +identity the problem is that if I start + + align:start position:0% +identity the problem is that if I start + + + align:start position:0% +identity the problem is that if I start +you know having the identity that goes + + align:start position:0% +you know having the identity that goes + + + align:start position:0% +you know having the identity that goes +here it's GNA start being a problem and + + align:start position:0% +here it's GNA start being a problem and + + + align:start position:0% +here it's GNA start being a problem and +this is the um um uh the the provit link + + align:start position:0% +this is the um um uh the the provit link + + + align:start position:0% +this is the um um uh the the provit link +the F inverse that you see here it's a + + align:start position:0% +the F inverse that you see here it's a + + + align:start position:0% +the F inverse that you see here it's a +little flatter uh I mean you can check + + align:start position:0% +little flatter uh I mean you can check + + + align:start position:0% +little flatter uh I mean you can check +right what uh you can compute the + + align:start position:0% +right what uh you can compute the + + + align:start position:0% +right what uh you can compute the +derivative uh at zero of those guys and + + align:start position:0% +derivative uh at zero of those guys and + + + align:start position:0% +derivative uh at zero of those guys and +you will see that the what is the + + align:start position:0% +you will see that the what is the + + + align:start position:0% +you will see that the what is the +derivative of + + align:start position:0% +derivative of + + + align:start position:0% +derivative of +the so log so I'm taking the derivative + + align:start position:0% +the so log so I'm taking the derivative + + + align:start position:0% +the so log so I'm taking the derivative +of log of x over 1 - x so it's uh 1 /x + + align:start position:0% +of log of x over 1 - x so it's uh 1 /x + + + align:start position:0% +of log of x over 1 - x so it's uh 1 /x +uh Min - one overx no uh minus one over + + align:start position:0% +uh Min - one overx no uh minus one over + + + align:start position:0% +uh Min - one overx no uh minus one over +1 - + + align:start position:0% + + + + align:start position:0% + +x okay so if I look at 0.5 actually + + align:start position:0% +x okay so if I look at 0.5 actually + + + align:start position:0% +x okay so if I look at 0.5 actually +sorry this is the interval 01 so I'm + + align:start position:0% +sorry this is the interval 01 so I'm + + + align:start position:0% +sorry this is the interval 01 so I'm +interested in the slope at 0.5 + + align:start position:0% +interested in the slope at 0.5 + + + align:start position:0% +interested in the slope at 0.5 +so no + + align:start position:0% +so no + + + align:start position:0% +so no +uh yes Plus thank you so at 0.5 what I + + align:start position:0% +uh yes Plus thank you so at 0.5 what I + + + align:start position:0% +uh yes Plus thank you so at 0.5 what I +get is uh 2 + two + + align:start position:0% + + + + align:start position:0% + +yeah okay so + + align:start position:0% +yeah okay so + + + align:start position:0% +yeah okay so +that's okay so that's the slope that we + + align:start position:0% +that's okay so that's the slope that we + + + align:start position:0% +that's okay so that's the slope that we +get and if you compute for uh + + align:start position:0% +get and if you compute for uh + + + align:start position:0% +get and if you compute for uh +derivative what is the derivative of f + + align:start position:0% +derivative what is the derivative of f + + + align:start position:0% +derivative what is the derivative of f +inverse well it's a little fi of x + + align:start position:0% +inverse well it's a little fi of x + + + align:start position:0% +inverse well it's a little fi of x +divided by little fi of capital F + + align:start position:0% +divided by little fi of capital F + + + align:start position:0% +divided by little fi of capital F +inverse of + + align:start position:0% +inverse of + + + align:start position:0% +inverse of +X so little fi + + align:start position:0% +X so little fi + + + align:start position:0% +X so little fi +at at one2 I don't + + align:start position:0% +at at one2 I don't + + + align:start position:0% +at at one2 I don't +know uh + + align:start position:0% + + + + align:start position:0% + +yeah I guess I can probably compute the + + align:start position:0% +yeah I guess I can probably compute the + + + align:start position:0% +yeah I guess I can probably compute the +derivative of capital fi at zero which + + align:start position:0% +derivative of capital fi at zero which + + + align:start position:0% +derivative of capital fi at zero which +is going to be just one over square2 pi + + align:start position:0% +is going to be just one over square2 pi + + + align:start position:0% +is going to be just one over square2 pi +and then just say well the slope has to + + align:start position:0% +and then just say well the slope has to + + + align:start position:0% +and then just say well the slope has to +be you know one over + + align:start position:0% +be you know one over + + + align:start position:0% +be you know one over +that um okay so you know S 2 pi + + align:start position:0% +that um okay so you know S 2 pi + + + align:start position:0% +that um okay so you know S 2 pi +um okay so that's just a comparison but + + align:start position:0% +um okay so that's just a comparison but + + + align:start position:0% +um okay so that's just a comparison but +again so far we do not have any reason + + align:start position:0% +again so far we do not have any reason + + + align:start position:0% +again so far we do not have any reason +to prefer one to the other and so now + + align:start position:0% +to prefer one to the other and so now + + + align:start position:0% +to prefer one to the other and so now +I'm going to start giving you some + + align:start position:0% +I'm going to start giving you some + + + align:start position:0% +I'm going to start giving you some +reasons to prefer one one to the other + + align:start position:0% +reasons to prefer one one to the other + + + align:start position:0% +reasons to prefer one one to the other +and uh one of those two and actually for + + align:start position:0% +and uh one of those two and actually for + + + align:start position:0% +and uh one of those two and actually for +each canonical family there is something + + align:start position:0% +each canonical family there is something + + + align:start position:0% +each canonical family there is something +which is called the canonical link and + + align:start position:0% +which is called the canonical link and + + + align:start position:0% +which is called the canonical link and +when you don't have any other reasons to + + align:start position:0% +when you don't have any other reasons to + + + align:start position:0% +when you don't have any other reasons to +choose anything else why not choose the + + align:start position:0% +choose anything else why not choose the + + + align:start position:0% +choose anything else why not choose the +canonical one and the canonical link is + + align:start position:0% +canonical one and the canonical link is + + + align:start position:0% +canonical one and the canonical link is +the one that says okay what I want is g + + align:start position:0% +the one that says okay what I want is g + + + align:start position:0% +the one that says okay what I want is g +to map me onto the real line + + align:start position:0% +to map me onto the real line + + + align:start position:0% +to map me onto the real line +right + + align:start position:0% +right + + + align:start position:0% +right +and but me is not the parameter of my + + align:start position:0% +and but me is not the parameter of my + + + align:start position:0% +and but me is not the parameter of my +canonical family right I mean it's just + + align:start position:0% +canonical family right I mean it's just + + + align:start position:0% +canonical family right I mean it's just +so here for example mu is e of theta but + + align:start position:0% +so here for example mu is e of theta but + + + align:start position:0% +so here for example mu is e of theta but +the canonical parameter is + + align:start position:0% +the canonical parameter is + + + align:start position:0% +the canonical parameter is +Theta and uh but the the parameter of a + + align:start position:0% +Theta and uh but the the parameter of a + + + align:start position:0% +Theta and uh but the the parameter of a +canonical exponential family is + + align:start position:0% +canonical exponential family is + + + align:start position:0% +canonical exponential family is +something that lives in the entire real + + align:start position:0% +something that lives in the entire real + + + align:start position:0% +something that lives in the entire real +line right it was defined for all + + align:start position:0% +line right it was defined for all + + + align:start position:0% +line right it was defined for all +thetas and so in particular I can just + + align:start position:0% +thetas and so in particular I can just + + + align:start position:0% +thetas and so in particular I can just +assume I can just take Theta to be the + + align:start position:0% +assume I can just take Theta to be the + + + align:start position:0% +assume I can just take Theta to be the +one that's X transposed Beta And so in + + align:start position:0% +one that's X transposed Beta And so in + + + align:start position:0% +one that's X transposed Beta And so in +particular I'm just going to try to find + + align:start position:0% +particular I'm just going to try to find + + + align:start position:0% +particular I'm just going to try to find +the link that just says okay okay when I + + align:start position:0% +the link that just says okay okay when I + + + align:start position:0% +the link that just says okay okay when I +take G of + + align:start position:0% +take G of + + + align:start position:0% +take G of +mu I'm going to map so that's what's + + align:start position:0% +mu I'm going to map so that's what's + + + align:start position:0% +mu I'm going to map so that's what's +going to be right so I know that g of mu + + align:start position:0% +going to be right so I know that g of mu + + + align:start position:0% +going to be right so I know that g of mu +is going to be equal to X beta and now + + align:start position:0% +is going to be equal to X beta and now + + + align:start position:0% +is going to be equal to X beta and now +what I'm going to say is say okay let's + + align:start position:0% +what I'm going to say is say okay let's + + + align:start position:0% +what I'm going to say is say okay let's +just take the G that makes this guy + + align:start position:0% +just take the G that makes this guy + + + align:start position:0% +just take the G that makes this guy +equal to Theta so that this is Theta + + align:start position:0% +equal to Theta so that this is Theta + + + align:start position:0% +equal to Theta so that this is Theta +that actually model like X transpose + + align:start position:0% +that actually model like X transpose + + + align:start position:0% +that actually model like X transpose +beta feels pretty + + align:start position:0% +beta feels pretty + + + align:start position:0% +beta feels pretty +canonical right I mean what + + align:start position:0% +canonical right I mean what + + + align:start position:0% +canonical right I mean what +else what other Central easy choice + + align:start position:0% +else what other Central easy choice + + + align:start position:0% +else what other Central easy choice +would you take this was pretty easy + + align:start position:0% +would you take this was pretty easy + + + align:start position:0% +would you take this was pretty easy +there's is a natural parameter for this + + align:start position:0% +there's is a natural parameter for this + + + align:start position:0% +there's is a natural parameter for this +canonical uh family and it takes value + + align:start position:0% +canonical uh family and it takes value + + + align:start position:0% +canonical uh family and it takes value +on the entire real line I have a + + align:start position:0% +on the entire real line I have a + + + align:start position:0% +on the entire real line I have a +function that Maps mu onto the entire + + align:start position:0% +function that Maps mu onto the entire + + + align:start position:0% +function that Maps mu onto the entire +real line so let's just map it to the + + align:start position:0% +real line so let's just map it to the + + + align:start position:0% +real line so let's just map it to the +actual + + align:start position:0% +actual + + + align:start position:0% +actual +parameter okay so now uh what I claim uh + + align:start position:0% +parameter okay so now uh what I claim uh + + + align:start position:0% +parameter okay so now uh what I claim uh +okay why do I have this well we've + + align:start position:0% +okay why do I have this well we've + + + align:start position:0% +okay why do I have this well we've +already figured that out the canonical + + align:start position:0% +already figured that out the canonical + + + align:start position:0% +already figured that out the canonical +link function is strictly increasing + + align:start position:0% +link function is strictly increasing + + + align:start position:0% +link function is strictly increasing +okay sorry so I said that so now I want + + align:start position:0% +okay sorry so I said that so now I want + + + align:start position:0% +okay sorry so I said that so now I want +this + + align:start position:0% +this + + + align:start position:0% +this +guy so I want + + align:start position:0% +guy so I want + + + align:start position:0% +guy so I want +mu G of + + align:start position:0% +mu G of + + + align:start position:0% +mu G of +mu to be equal to Theta + + align:start position:0% +mu to be equal to Theta + + + align:start position:0% +mu to be equal to Theta +which is equivalent to saying that I + + align:start position:0% +which is equivalent to saying that I + + + align:start position:0% +which is equivalent to saying that I +want mu to be equal to G inverse of + + align:start position:0% +want mu to be equal to G inverse of + + + align:start position:0% +want mu to be equal to G inverse of +theta but we know that mu is + + align:start position:0% +theta but we know that mu is + + + align:start position:0% +theta but we know that mu is +what B Prime of + + align:start position:0% + + + + align:start position:0% + +theta so that means that b Prime is the + + align:start position:0% +theta so that means that b Prime is the + + + align:start position:0% +theta so that means that b Prime is the +same function as G + + align:start position:0% +same function as G + + + align:start position:0% +same function as G +inverse and I claim that this is + + align:start position:0% +inverse and I claim that this is + + + align:start position:0% +inverse and I claim that this is +actually giving me indeed a function + + align:start position:0% +actually giving me indeed a function + + + align:start position:0% +actually giving me indeed a function +that has uh the properties that I want + + align:start position:0% +that has uh the properties that I want + + + align:start position:0% +that has uh the properties that I want +because before I said just pick any + + align:start position:0% +because before I said just pick any + + + align:start position:0% +because before I said just pick any +function that has these properties and + + align:start position:0% +function that has these properties and + + + align:start position:0% +function that has these properties and +now I'm giving you a very hard rule to + + align:start position:0% +now I'm giving you a very hard rule to + + + align:start position:0% +now I'm giving you a very hard rule to +pick this though you need still to check + + align:start position:0% +pick this though you need still to check + + + align:start position:0% +pick this though you need still to check +that it satisfies those condition in + + align:start position:0% +that it satisfies those condition in + + + align:start position:0% +that it satisfies those condition in +particular that it's increasing and + + align:start position:0% +particular that it's increasing and + + + align:start position:0% +particular that it's increasing and +invertible and so for this to be + + align:start position:0% +invertible and so for this to be + + + align:start position:0% +invertible and so for this to be +increasing and invertible strictly + + align:start position:0% +increasing and invertible strictly + + + align:start position:0% +increasing and invertible strictly +increasing and invertible really what I + + align:start position:0% +increasing and invertible really what I + + + align:start position:0% +increasing and invertible really what I +need is that the inverse is strictly + + align:start position:0% +need is that the inverse is strictly + + + align:start position:0% +need is that the inverse is strictly +increasing and invertible which is the + + align:start position:0% +increasing and invertible which is the + + + align:start position:0% +increasing and invertible which is the +case here because uh uh B Prime as we + + align:start position:0% +case here because uh uh B Prime as we + + + align:start position:0% +case here because uh uh B Prime as we +said well B Prime is the derivative of a + + align:start position:0% +said well B Prime is the derivative of a + + + align:start position:0% +said well B Prime is the derivative of a +strictly convex function a strictly + + align:start position:0% +strictly convex function a strictly + + + align:start position:0% +strictly convex function a strictly +convex function has a second derivative + + align:start position:0% +convex function has a second derivative + + + align:start position:0% +convex function has a second derivative +that's strictly positive we just figured + + align:start position:0% +that's strictly positive we just figured + + + align:start position:0% +that's strictly positive we just figured +it out using the fact that the variance + + align:start position:0% +it out using the fact that the variance + + + align:start position:0% +it out using the fact that the variance +was strictly positive and if f is + + align:start position:0% +was strictly positive and if f is + + + align:start position:0% +was strictly positive and if f is +strictly positive then uh this thing has + + align:start position:0% +strictly positive then uh this thing has + + + align:start position:0% +strictly positive then uh this thing has +to be uh strictly positive so if B prime + + align:start position:0% +to be uh strictly positive so if B prime + + + align:start position:0% +to be uh strictly positive so if B prime +prime is strictly positive this is the + + align:start position:0% +prime is strictly positive this is the + + + align:start position:0% +prime is strictly positive this is the +derivative of a function called B Prime + + align:start position:0% +derivative of a function called B Prime + + + align:start position:0% +derivative of a function called B Prime +if your derivative is strictly positive + + align:start position:0% +if your derivative is strictly positive + + + align:start position:0% +if your derivative is strictly positive +you are strictly + + align:start position:0% +you are strictly + + + align:start position:0% +you are strictly +increasing and so we know that b Prime + + align:start position:0% +increasing and so we know that b Prime + + + align:start position:0% +increasing and so we know that b Prime +is indeed strictly + + align:start position:0% + + + + align:start position:0% + +increasing and uh what I need also to + + align:start position:0% +increasing and uh what I need also to + + + align:start position:0% +increasing and uh what I need also to +check well I guess uh this is already + + align:start position:0% +check well I guess uh this is already + + + align:start position:0% +check well I guess uh this is already +checked in its own because B Prime is + + align:start position:0% +checked in its own because B Prime is + + + align:start position:0% +checked in its own because B Prime is +actually um mapping all of R into uh the + + align:start position:0% +actually um mapping all of R into uh the + + + align:start position:0% +actually um mapping all of R into uh the +the possible values I mean when Theta + + align:start position:0% +the possible values I mean when Theta + + + align:start position:0% +the possible values I mean when Theta +ranges on the entire real line then B + + align:start position:0% +ranges on the entire real line then B + + + align:start position:0% +ranges on the entire real line then B +Prime ranges in the entire interval of + + align:start position:0% +Prime ranges in the entire interval of + + + align:start position:0% +Prime ranges in the entire interval of +the the mean values that it can take + + align:start position:0% +the the mean values that it can take + + + align:start position:0% +the the mean values that it can take +right and so now I have this thing + + align:start position:0% +right and so now I have this thing + + + align:start position:0% +right and so now I have this thing +that's completely defined B Prime + + align:start position:0% +that's completely defined B Prime + + + align:start position:0% +that's completely defined B Prime +inverse is a valid + + align:start position:0% + + + + align:start position:0% + +link and it's called the canonical + + align:start position:0% + + + + align:start position:0% + +link okay so again if I give you an + + align:start position:0% +link okay so again if I give you an + + + align:start position:0% +link okay so again if I give you an +exponential family which is another way + + align:start position:0% +exponential family which is another way + + + align:start position:0% +exponential family which is another way +of saying you I give you a convex + + align:start position:0% +of saying you I give you a convex + + + align:start position:0% +of saying you I give you a convex +function B which you know gives you some + + align:start position:0% +function B which you know gives you some + + + align:start position:0% +function B which you know gives you some +exponential family then if you just take + + align:start position:0% +exponential family then if you just take + + + align:start position:0% +exponential family then if you just take +B Prime inverse this gives you the + + align:start position:0% +B Prime inverse this gives you the + + + align:start position:0% +B Prime inverse this gives you the +associated canonical link for this + + align:start position:0% +associated canonical link for this + + + align:start position:0% +associated canonical link for this +canonical exponential family all + + align:start position:0% +canonical exponential family all + + + align:start position:0% +canonical exponential family all +right so let's see why so okay clearly + + align:start position:0% +right so let's see why so okay clearly + + + align:start position:0% +right so let's see why so okay clearly +there's an advantage of doing this which + + align:start position:0% +there's an advantage of doing this which + + + align:start position:0% +there's an advantage of doing this which +is is I don't have to actually think + + align:start position:0% +is is I don't have to actually think + + + align:start position:0% +is is I don't have to actually think +about which one to pick if I don't want + + align:start position:0% +about which one to pick if I don't want + + + align:start position:0% +about which one to pick if I don't want +to think about it but uh uh there's + + align:start position:0% +to think about it but uh uh there's + + + align:start position:0% +to think about it but uh uh there's +other advantages that come to it and + + align:start position:0% +other advantages that come to it and + + + align:start position:0% +other advantages that come to it and +we'll see that in the representation + + align:start position:0% +we'll see that in the representation + + + align:start position:0% +we'll see that in the representation +there's basically going to be some life + + align:start position:0% +there's basically going to be some life + + + align:start position:0% +there's basically going to be some life +cancellations that show up so before we + + align:start position:0% +cancellations that show up so before we + + + align:start position:0% +cancellations that show up so before we +go there let's just compute the + + align:start position:0% +go there let's just compute the + + + align:start position:0% +go there let's just compute the +canonical link for the burnly + + align:start position:0% +canonical link for the burnly + + + align:start position:0% +canonical link for the burnly +distribution all right so remember the + + align:start position:0% +distribution all right so remember the + + + align:start position:0% +distribution all right so remember the +burnly distribution has a + + align:start position:0% + + + + align:start position:0% + +pmf which is part of the canonical + + align:start position:0% +pmf which is part of the canonical + + + align:start position:0% +pmf which is part of the canonical +exponential family all right so the pmf + + align:start position:0% +exponential family all right so the pmf + + + align:start position:0% +exponential family all right so the pmf +of the burnly is um uh F Theta of + + align:start position:0% +of the burnly is um uh F Theta of + + + align:start position:0% +of the burnly is um uh F Theta of +X is + + align:start position:0% +X is + + + align:start position:0% +X is +uh okay + + align:start position:0% +uh okay + + + align:start position:0% +uh okay +so let me just write it like this so + + align:start position:0% +so let me just write it like this so + + + align:start position:0% +so let me just write it like this so +it's p to the x one so P to the Y let's + + align:start position:0% +it's p to the x one so P to the Y let's + + + align:start position:0% +it's p to the x one so P to the Y let's +say one minus P to the 1 minus + + align:start position:0% +say one minus P to the 1 minus + + + align:start position:0% +say one minus P to the 1 minus +y which I will write as + + align:start position:0% +y which I will write as + + + align:start position:0% +y which I will write as +exponential y log + + align:start position:0% +exponential y log + + + align:start position:0% +exponential y log +P plus uh oneus + + align:start position:0% +P plus uh oneus + + + align:start position:0% +P plus uh oneus +y log 1 minus + + align:start position:0% +y log 1 minus + + + align:start position:0% +y log 1 minus +P okay we've done that last time now I'm + + align:start position:0% +P okay we've done that last time now I'm + + + align:start position:0% +P okay we've done that last time now I'm +going to group my terms in y to see how + + align:start position:0% +going to group my terms in y to see how + + + align:start position:0% +going to group my terms in y to see how +y interacts with this parameter + + align:start position:0% +y interacts with this parameter + + + align:start position:0% +y interacts with this parameter +p and what I'm getting is Y which is + + align:start position:0% +p and what I'm getting is Y which is + + + align:start position:0% +p and what I'm getting is Y which is +time log P / 1 minus p and then the only + + align:start position:0% +time log P / 1 minus p and then the only + + + align:start position:0% +time log P / 1 minus p and then the only +term that remains is log 1 minus + + align:start position:0% +term that remains is log 1 minus + + + align:start position:0% +term that remains is log 1 minus +P + + align:start position:0% +P + + + align:start position:0% +P +okay now I want this to be a canonical + + align:start position:0% +okay now I want this to be a canonical + + + align:start position:0% +okay now I want this to be a canonical +exponential family which means that I + + align:start position:0% +exponential family which means that I + + + align:start position:0% +exponential family which means that I +just need to call this guy so it is part + + align:start position:0% +just need to call this guy so it is part + + + align:start position:0% +just need to call this guy so it is part +of the exponential family I can read + + align:start position:0% +of the exponential family I can read + + + align:start position:0% +of the exponential family I can read +that if I want it to be canonical this + + align:start position:0% +that if I want it to be canonical this + + + align:start position:0% +that if I want it to be canonical this +guy must be Theta + + align:start position:0% +guy must be Theta + + + align:start position:0% +guy must be Theta +itself okay so I have that Theta is + + align:start position:0% +itself okay so I have that Theta is + + + align:start position:0% +itself okay so I have that Theta is +equal to log P 1 minus P if I invert + + align:start position:0% +equal to log P 1 minus P if I invert + + + align:start position:0% +equal to log P 1 minus P if I invert +this thing it tells me that P is e to + + align:start position:0% +this thing it tells me that P is e to + + + align:start position:0% +this thing it tells me that P is e to +the Theta / 1 + e to the Theta right + + align:start position:0% +the Theta / 1 + e to the Theta right + + + align:start position:0% +the Theta / 1 + e to the Theta right +it's just inverting this + + align:start position:0% +it's just inverting this + + + align:start position:0% +it's just inverting this +function and so that means that this + + align:start position:0% +function and so that means that this + + + align:start position:0% +function and so that means that this +thing is actually so in particular it + + align:start position:0% +thing is actually so in particular it + + + align:start position:0% +thing is actually so in particular it +means that + + align:start position:0% +means that + + + align:start position:0% +means that +log 1 - p is equal to log 1 minus this + + align:start position:0% +log 1 - p is equal to log 1 minus this + + + align:start position:0% +log 1 - p is equal to log 1 minus this +thing so the exponential thetas go away + + align:start position:0% +thing so the exponential thetas go away + + + align:start position:0% +thing so the exponential thetas go away +so in the numerator so this is what I + + align:start position:0% +so in the numerator so this is what I + + + align:start position:0% +so in the numerator so this is what I +get right that's the log one minus this + + align:start position:0% +get right that's the log one minus this + + + align:start position:0% +get right that's the log one minus this +guy which is equal to minus log 1 + e to + + align:start position:0% +guy which is equal to minus log 1 + e to + + + align:start position:0% +guy which is equal to minus log 1 + e to +the + + align:start position:0% +the + + + align:start position:0% +the +Theta + + align:start position:0% + + + + align:start position:0% + +okay so I'm going a bit fast but these + + align:start position:0% +okay so I'm going a bit fast but these + + + align:start position:0% +okay so I'm going a bit fast but these +are very Elementary + + align:start position:0% +are very Elementary + + + align:start position:0% +are very Elementary +manipulations Maybe it requires one more + + align:start position:0% +manipulations Maybe it requires one more + + + align:start position:0% +manipulations Maybe it requires one more +line to convince yourself but + + align:start position:0% +line to convince yourself but + + + align:start position:0% +line to convince yourself but +uh + + align:start position:0% +uh + + + align:start position:0% +uh +just do it in the comfort of your room + + align:start position:0% +just do it in the comfort of your room + + + align:start position:0% +just do it in the comfort of your room +and then what you have is the + + align:start position:0% +and then what you have is the + + + align:start position:0% +and then what you have is the +exponential of y * Theta and then I have + + align:start position:0% +exponential of y * Theta and then I have + + + align:start position:0% +exponential of y * Theta and then I have +minus log 1 + e + + align:start position:0% +minus log 1 + e + + + align:start position:0% +minus log 1 + e +Theta okay so this is the representation + + align:start position:0% +Theta okay so this is the representation + + + align:start position:0% +Theta okay so this is the representation +of the pmf of a burnly distribution as + + align:start position:0% +of the pmf of a burnly distribution as + + + align:start position:0% +of the pmf of a burnly distribution as +part of a member of the canonical + + align:start position:0% +part of a member of the canonical + + + align:start position:0% +part of a member of the canonical +exponential family and it tells me that + + align:start position:0% +exponential family and it tells me that + + + align:start position:0% +exponential family and it tells me that +b of theta is + + align:start position:0% +b of theta is + + + align:start position:0% +b of theta is +equal to log 1 plus e of + + align:start position:0% +equal to log 1 plus e of + + + align:start position:0% +equal to log 1 plus e of +theta that's what I have there from + + align:start position:0% +theta that's what I have there from + + + align:start position:0% +theta that's what I have there from +there I can compute the expectation + + align:start position:0% +there I can compute the expectation + + + align:start position:0% +there I can compute the expectation +which you know hopefully I'm going to + + align:start position:0% +which you know hopefully I'm going to + + + align:start position:0% +which you know hopefully I'm going to +get p as the mean and P * 1 minus p as + + align:start position:0% +get p as the mean and P * 1 minus p as + + + align:start position:0% +get p as the mean and P * 1 minus p as +the variance otherwise that would be + + align:start position:0% +the variance otherwise that would be + + + align:start position:0% +the variance otherwise that would be +weird + + align:start position:0% +weird + + + align:start position:0% +weird +um so let's just do + + align:start position:0% + + + + align:start position:0% + +this B + + align:start position:0% +this B + + + align:start position:0% +this B +Prime of theta should give me the mean + + align:start position:0% +Prime of theta should give me the mean + + + align:start position:0% +Prime of theta should give me the mean +and indeed B Prime of theta is e to the + + align:start position:0% +and indeed B Prime of theta is e to the + + + align:start position:0% +and indeed B Prime of theta is e to the +Theta divided by 1+ e to the Theta which + + align:start position:0% +Theta divided by 1+ e to the Theta which + + + align:start position:0% +Theta divided by 1+ e to the Theta which +is exactly this spe that I had + + align:start position:0% + + + + align:start position:0% + +there okay just for fun uh let's uh well + + align:start position:0% +there okay just for fun uh let's uh well + + + align:start position:0% +there okay just for fun uh let's uh well +I don't know maybe that's not part of it + + align:start position:0% +I don't know maybe that's not part of it + + + align:start position:0% +I don't know maybe that's not part of it +yeah let's not compute the second + + align:start position:0% +yeah let's not compute the second + + + align:start position:0% +yeah let's not compute the second +derivative it's probably going to be on + + align:start position:0% +derivative it's probably going to be on + + + align:start position:0% +derivative it's probably going to be on +your homework at some point um if not on + + align:start position:0% +your homework at some point um if not on + + + align:start position:0% +your homework at some point um if not on +the + + align:start position:0% +the + + + align:start position:0% +the +final uh all right + + align:start position:0% +final uh all right + + + align:start position:0% +final uh all right +so B Prime now we know oh I erased it of + + align:start position:0% +so B Prime now we know oh I erased it of + + + align:start position:0% +so B Prime now we know oh I erased it of +course um G the canonical link is B + + align:start position:0% +course um G the canonical link is B + + + align:start position:0% +course um G the canonical link is B +Prime + + align:start position:0% + + + + align:start position:0% + +inverse and I claim that this is going + + align:start position:0% +inverse and I claim that this is going + + + align:start position:0% +inverse and I claim that this is going +to give me the legit function log of mu + + align:start position:0% +to give me the legit function log of mu + + + align:start position:0% +to give me the legit function log of mu +over 1 minus mu so let's check that so B + + align:start position:0% +over 1 minus mu so let's check that so B + + + align:start position:0% +over 1 minus mu so let's check that so B +Prime is this thing uh so now I want to + + align:start position:0% +Prime is this thing uh so now I want to + + + align:start position:0% +Prime is this thing uh so now I want to +find the inverse + + align:start position:0% + + + + align:start position:0% + +well I should really call my inverse of + + align:start position:0% +well I should really call my inverse of + + + align:start position:0% +well I should really call my inverse of +function of p and I've done it before + + align:start position:0% +function of p and I've done it before + + + align:start position:0% +function of p and I've done it before +right all I have to do is to solve this + + align:start position:0% +right all I have to do is to solve this + + + align:start position:0% +right all I have to do is to solve this +equation which I've actually just done + + align:start position:0% +equation which I've actually just done + + + align:start position:0% +equation which I've actually just done +it that's where I'm actually coming from + + align:start position:0% +it that's where I'm actually coming from + + + align:start position:0% +it that's where I'm actually coming from +so it's actually telling me that the + + align:start position:0% +so it's actually telling me that the + + + align:start position:0% +so it's actually telling me that the +solution of this thing is uh equal to + + align:start position:0% +solution of this thing is uh equal to + + + align:start position:0% +solution of this thing is uh equal to +log of p over 1 minus + + align:start position:0% + + + + align:start position:0% + +P + + align:start position:0% +P + + + align:start position:0% +P +okay we just solve this thing both ways + + align:start position:0% +okay we just solve this thing both ways + + + align:start position:0% +okay we just solve this thing both ways +and this is + + align:start position:0% +and this is + + + align:start position:0% +and this is +indeed + + align:start position:0% +indeed + + + align:start position:0% +indeed +logit of P by definition of + + align:start position:0% +logit of P by definition of + + + align:start position:0% +logit of P by definition of +logit so B Prime inverse this function + + align:start position:0% +logit so B Prime inverse this function + + + align:start position:0% +logit so B Prime inverse this function +that seemed to come out of nowhere is + + align:start position:0% +that seemed to come out of nowhere is + + + align:start position:0% +that seemed to come out of nowhere is +really just the inverse of B Prime which + + align:start position:0% +really just the inverse of B Prime which + + + align:start position:0% +really just the inverse of B Prime which +we know is the canonical link and + + align:start position:0% +we know is the canonical link and + + + align:start position:0% +we know is the canonical link and +canonical is some sort of ad hoc choices + + align:start position:0% +canonical is some sort of ad hoc choices + + + align:start position:0% +canonical is some sort of ad hoc choices +that we've made by saying let's just + + align:start position:0% +that we've made by saying let's just + + + align:start position:0% +that we've made by saying let's just +take the link such that D of mu is + + align:start position:0% +take the link such that D of mu is + + + align:start position:0% +take the link such that D of mu is +giving me the actual canonical parameter + + align:start position:0% +giving me the actual canonical parameter + + + align:start position:0% +giving me the actual canonical parameter +f + + align:start position:0% + + + + align:start position:0% + +yeah yeah you're + + align:start position:0% + + + + align:start position:0% + +right um now of course I'm going through + + align:start position:0% +right um now of course I'm going through + + + align:start position:0% +right um now of course I'm going through +all this trouble but you could see it + + align:start position:0% +all this trouble but you could see it + + + align:start position:0% +all this trouble but you could see it +immediately I know this is going to be + + align:start position:0% +immediately I know this is going to be + + + align:start position:0% +immediately I know this is going to be +Theta we also have FR knowledge + + align:start position:0% +Theta we also have FR knowledge + + + align:start position:0% +Theta we also have FR knowledge +hopefully that the expectation of a + + align:start position:0% +hopefully that the expectation of a + + + align:start position:0% +hopefully that the expectation of a +burnly is p itself so right at this step + + align:start position:0% +burnly is p itself so right at this step + + + align:start position:0% +burnly is p itself so right at this step +when I say that I'm going going to take + + align:start position:0% +when I say that I'm going going to take + + + align:start position:0% +when I say that I'm going going to take +Theta to be this guy already knew that + + align:start position:0% +Theta to be this guy already knew that + + + align:start position:0% +Theta to be this guy already knew that +the canonical link was the late + + align:start position:0% +the canonical link was the late + + + align:start position:0% +the canonical link was the late +link because I just say oh here is Theta + + align:start position:0% +link because I just say oh here is Theta + + + align:start position:0% +link because I just say oh here is Theta +and it's just this function of me + + align:start position:0% + + + + align:start position:0% + +B okay so you can do that for a bunch of + + align:start position:0% +B okay so you can do that for a bunch of + + + align:start position:0% +B okay so you can do that for a bunch of +examples and this is what they're going + + align:start position:0% +examples and this is what they're going + + + align:start position:0% +examples and this is what they're going +to give you so in the gaussian case b of + + align:start position:0% +to give you so in the gaussian case b of + + + align:start position:0% +to give you so in the gaussian case b of +theta we've actually computed it + + align:start position:0% +theta we've actually computed it + + + align:start position:0% +theta we've actually computed it +actually once this is Theta Square over + + align:start position:0% +actually once this is Theta Square over + + + align:start position:0% +actually once this is Theta Square over +two so the derivative of this thing is + + align:start position:0% +two so the derivative of this thing is + + + align:start position:0% +two so the derivative of this thing is +really just Theta which means that g or + + align:start position:0% +really just Theta which means that g or + + + align:start position:0% +really just Theta which means that g or +G inverse is actually equal to the + + align:start position:0% +G inverse is actually equal to the + + + align:start position:0% +G inverse is actually equal to the +identity okay and again sort of you know + + align:start position:0% +identity okay and again sort of you know + + + align:start position:0% +identity okay and again sort of you know +sanity check when I'm in the gaon case + + align:start position:0% +sanity check when I'm in the gaon case + + + align:start position:0% +sanity check when I'm in the gaon case +there's nothing General about General + + align:start position:0% +there's nothing General about General + + + align:start position:0% +there's nothing General about General +linear models they don't have a link the + + align:start position:0% +linear models they don't have a link the + + + align:start position:0% +linear models they don't have a link the +pon case uh you can actually check uh + + align:start position:0% +pon case uh you can actually check uh + + + align:start position:0% +pon case uh you can actually check uh +did we do this actually yes we did it + + align:start position:0% +did we do this actually yes we did it + + + align:start position:0% +did we do this actually yes we did it +right so that's when we had this e of + + align:start position:0% +right so that's when we had this e of + + + align:start position:0% +right so that's when we had this e of +theta and so B is e of theta which means + + align:start position:0% +theta and so B is e of theta which means + + + align:start position:0% +theta and so B is e of theta which means +that the natural link is the E inverse + + align:start position:0% +that the natural link is the E inverse + + + align:start position:0% +that the natural link is the E inverse +which is log uh which is the inverse of + + align:start position:0% +which is log uh which is the inverse of + + + align:start position:0% +which is log uh which is the inverse of +exponential and so that's the log + + align:start position:0% +exponential and so that's the log + + + align:start position:0% +exponential and so that's the log +logarithm link which as I said you know + + align:start position:0% +logarithm link which as I said you know + + + align:start position:0% +logarithm link which as I said you know +I I use the word natural but you can + + align:start position:0% +I I use the word natural but you can + + + align:start position:0% +I I use the word natural but you can +also use the word canonical if you want + + align:start position:0% +also use the word canonical if you want + + + align:start position:0% +also use the word canonical if you want +to describe this function as being the + + align:start position:0% +to describe this function as being the + + + align:start position:0% +to describe this function as being the +right function to map the positive real + + align:start position:0% +right function to map the positive real + + + align:start position:0% +right function to map the positive real +line to the entire real line the burnly + + align:start position:0% +line to the entire real line the burnly + + + align:start position:0% +line to the entire real line the burnly +would just did it so B the cumulative + + align:start position:0% +would just did it so B the cumulative + + + align:start position:0% +would just did it so B the cumulative +cumul during function is log of 1 plus e + + align:start position:0% +cumul during function is log of 1 plus e + + + align:start position:0% +cumul during function is log of 1 plus e +of theta which is log of uh mu over 1us + + align:start position:0% +of theta which is log of uh mu over 1us + + + align:start position:0% +of theta which is log of uh mu over 1us +mu and uh and Gamma fun function where + + align:start position:0% +mu and uh and Gamma fun function where + + + align:start position:0% +mu and uh and Gamma fun function where +you have the thing you're going to see + + align:start position:0% +you have the thing you're going to see + + + align:start position:0% +you have the thing you're going to see +is log minus log of minus denta you've + + align:start position:0% +is log minus log of minus denta you've + + + align:start position:0% +is log minus log of minus denta you've +see this this the reciprocal link is the + + align:start position:0% +see this this the reciprocal link is the + + + align:start position:0% +see this this the reciprocal link is the +link that actually shows up so uh minus + + align:start position:0% +link that actually shows up so uh minus + + + align:start position:0% +link that actually shows up so uh minus +one over mu okay that Maps this is + + align:start position:0% +one over mu okay that Maps this is + + + align:start position:0% +one over mu okay that Maps this is +another uh link sorry this is um + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +uh yeah okay that's the + + align:start position:0% +uh yeah okay that's the + + + align:start position:0% +uh yeah okay that's the +one okay so um are there any questions + + align:start position:0% +one okay so um are there any questions + + + align:start position:0% +one okay so um are there any questions +about canonical links canonical + + align:start position:0% +about canonical links canonical + + + align:start position:0% +about canonical links canonical +families I use the word canonical a lot + + align:start position:0% +families I use the word canonical a lot + + + align:start position:0% +families I use the word canonical a lot +uh but uh is everything fitting together + + align:start position:0% +uh but uh is everything fitting together + + + align:start position:0% +uh but uh is everything fitting together +right now right so we have this function + + align:start position:0% +right now right so we have this function + + + align:start position:0% +right now right so we have this function +we have the canonical exponential family + + align:start position:0% +we have the canonical exponential family + + + align:start position:0% +we have the canonical exponential family +by assumption it has a function B which + + align:start position:0% +by assumption it has a function B which + + + align:start position:0% +by assumption it has a function B which +contains every information we want we + + align:start position:0% +contains every information we want we + + + align:start position:0% +contains every information we want we +just at the beginning of the lecture we + + align:start position:0% +just at the beginning of the lecture we + + + align:start position:0% +just at the beginning of the lecture we +established that it has information + + align:start position:0% +established that it has information + + + align:start position:0% +established that it has information +about the mean in the first derivative + + align:start position:0% +about the mean in the first derivative + + + align:start position:0% +about the mean in the first derivative +about the variance in the second + + align:start position:0% +about the variance in the second + + + align:start position:0% +about the variance in the second +derivative and it's also giving us the + + align:start position:0% +derivative and it's also giving us the + + + align:start position:0% +derivative and it's also giving us the +canonical link all right so just cherish + + align:start position:0% +canonical link all right so just cherish + + + align:start position:0% +canonical link all right so just cherish +this B once you found it because it's + + align:start position:0% +this B once you found it because it's + + + align:start position:0% +this B once you found it because it's +everything you need + + align:start position:0% + + + + align:start position:0% + +yeah uh I don't know um political + + align:start position:0% + + + + align:start position:0% + +preference um you know uh I don't know + + align:start position:0% +preference um you know uh I don't know + + + align:start position:0% +preference um you know uh I don't know +honestly + + align:start position:0% +honestly + + + align:start position:0% +honestly +if I were you know a serious + + align:start position:0% +if I were you know a serious + + + align:start position:0% +if I were you know a serious +practitioner I probably would have a + + align:start position:0% +practitioner I probably would have a + + + align:start position:0% +practitioner I probably would have a +better answer for you at this point I + + align:start position:0% +better answer for you at this point I + + + align:start position:0% +better answer for you at this point I +just don't I think it's a matter of + + align:start position:0% +just don't I think it's a matter of + + + align:start position:0% +just don't I think it's a matter of +practice and and and actual preferences + + align:start position:0% +practice and and and actual preferences + + + align:start position:0% +practice and and and actual preferences +you can also try both we didn't mention + + align:start position:0% +you can also try both we didn't mention + + + align:start position:0% +you can also try both we didn't mention +that you know there's this idea of crow + + align:start position:0% +that you know there's this idea of crow + + + align:start position:0% +that you know there's this idea of crow +validation well we mentioned it without + + align:start position:0% +validation well we mentioned it without + + + align:start position:0% +validation well we mentioned it without +going too much into details but you know + + align:start position:0% +going too much into details but you know + + + align:start position:0% +going too much into details but you know +you could try both and see which one + + align:start position:0% +you could try both and see which one + + + align:start position:0% +you could try both and see which one +performs best on a yet data set in terms + + align:start position:0% +performs best on a yet data set in terms + + + align:start position:0% +performs best on a yet data set in terms +of prediction and just say I prefer this + + align:start position:0% +of prediction and just say I prefer this + + + align:start position:0% +of prediction and just say I prefer this +one of the two because this actually + + align:start position:0% +one of the two because this actually + + + align:start position:0% +one of the two because this actually +comes as part of your modeling + + align:start position:0% +comes as part of your modeling + + + align:start position:0% +comes as part of your modeling +assumption right you modeled not only + + align:start position:0% +assumption right you modeled not only + + + align:start position:0% +assumption right you modeled not only +did you decide to model the image of me + + align:start position:0% +did you decide to model the image of me + + + align:start position:0% +did you decide to model the image of me +through the link function as a linear + + align:start position:0% +through the link function as a linear + + + align:start position:0% +through the link function as a linear +model but you really really what you're + + align:start position:0% +model but you really really what you're + + + align:start position:0% +model but you really really what you're +saying right your model is saying well + + align:start position:0% +saying right your model is saying well + + + align:start position:0% +saying right your model is saying well +so you have two pieces of M the + + align:start position:0% +so you have two pieces of M the + + + align:start position:0% +so you have two pieces of M the +distribution of Y but you also have the + + align:start position:0% +distribution of Y but you also have the + + + align:start position:0% +distribution of Y but you also have the +fact that mu is modeled as G inverse of + + align:start position:0% +fact that mu is modeled as G inverse of + + + align:start position:0% +fact that mu is modeled as G inverse of +X transpose beta and for different G's + + align:start position:0% +X transpose beta and for different G's + + + align:start position:0% +X transpose beta and for different G's +this is just different modeling + + align:start position:0% +this is just different modeling + + + align:start position:0% +this is just different modeling +assumptions right + + align:start position:0% + + + + align:start position:0% + +so you know why should this be be linear + + align:start position:0% +so you know why should this be be linear + + + align:start position:0% +so you know why should this be be linear +this thing be linear I don't know my my + + align:start position:0% +this thing be linear I don't know my my + + + align:start position:0% +this thing be linear I don't know my my +you know my authority uh as a person + + align:start position:0% +you know my authority uh as a person + + + align:start position:0% +you know my authority uh as a person +who's not examined the tal and data sets + + align:start position:0% +who's not examined the tal and data sets + + + align:start position:0% +who's not examined the tal and data sets +uh for both things would be that the + + align:start position:0% +uh for both things would be that the + + + align:start position:0% +uh for both things would be that the +changes are fairly + + align:start position:0% + + + + align:start position:0% + +minor okay so this was all for one + + align:start position:0% +minor okay so this was all for one + + + align:start position:0% +minor okay so this was all for one +observation we just you know basically + + align:start position:0% +observation we just you know basically + + + align:start position:0% +observation we just you know basically +did probility right we describe some + + align:start position:0% +did probility right we describe some + + + align:start position:0% +did probility right we describe some +densities some properties of the + + align:start position:0% +densities some properties of the + + + align:start position:0% +densities some properties of the +densities how to compute expectations + + align:start position:0% +densities how to compute expectations + + + align:start position:0% +densities how to compute expectations +that was really just probability there + + align:start position:0% +that was really just probability there + + + align:start position:0% +that was really just probability there +was no dat invol evolved at any point we + + align:start position:0% +was no dat invol evolved at any point we + + + align:start position:0% +was no dat invol evolved at any point we +did a bit of modeling it was all for one + + align:start position:0% +did a bit of modeling it was all for one + + + align:start position:0% +did a bit of modeling it was all for one +observation what we're going to try to + + align:start position:0% +observation what we're going to try to + + + align:start position:0% +observation what we're going to try to +do now is given do the you know the + + align:start position:0% +do now is given do the you know the + + + align:start position:0% +do now is given do the you know the +reverse engineering to probability that + + align:start position:0% +reverse engineering to probability that + + + align:start position:0% +reverse engineering to probability that +is statistics given data what can I + + align:start position:0% +is statistics given data what can I + + + align:start position:0% +is statistics given data what can I +infer about my model now remember + + align:start position:0% +infer about my model now remember + + + align:start position:0% +infer about my model now remember +there's three parameters that are sort + + align:start position:0% +there's three parameters that are sort + + + align:start position:0% +there's three parameters that are sort +of floating around in this model right + + align:start position:0% +of floating around in this model right + + + align:start position:0% +of floating around in this model right +there one that was + + align:start position:0% +there one that was + + + align:start position:0% +there one that was +Theta there one that was mu and there + + align:start position:0% +Theta there one that was mu and there + + + align:start position:0% +Theta there one that was mu and there +one that is beta okay so those are the + + align:start position:0% +one that is beta okay so those are the + + + align:start position:0% +one that is beta okay so those are the +three parameters that are floating + + align:start position:0% +three parameters that are floating + + + align:start position:0% +three parameters that are floating +around what we wanted to say what we + + align:start position:0% +around what we wanted to say what we + + + align:start position:0% +around what we wanted to say what we +said is that the + + align:start position:0% +said is that the + + + align:start position:0% +said is that the +expectation of Y given X is Mu of + + align:start position:0% +expectation of Y given X is Mu of + + + align:start position:0% +expectation of Y given X is Mu of +X okay so if I estimate mu I know the + + align:start position:0% +X okay so if I estimate mu I know the + + + align:start position:0% +X okay so if I estimate mu I know the +conditional expectation of Y given X + + align:start position:0% +conditional expectation of Y given X + + + align:start position:0% +conditional expectation of Y given X +which definitely gives + + align:start position:0% +which definitely gives + + + align:start position:0% +which definitely gives +me Theta of X right how do I go from U + + align:start position:0% +me Theta of X right how do I go from U + + + align:start position:0% +me Theta of X right how do I go from U +of x to Theta of + + align:start position:0% + + + + align:start position:0% + +X + + align:start position:0% +X + + + align:start position:0% +X +yeah the inverse of what + + align:start position:0% + + + + align:start position:0% + +of the + + align:start position:0% +of the + + + align:start position:0% +of the +arrow yeah sure but how do I uh how do I + + align:start position:0% +arrow yeah sure but how do I uh how do I + + + align:start position:0% +arrow yeah sure but how do I uh how do I +go from this guy to this + + align:start position:0% +go from this guy to this + + + align:start position:0% +go from this guy to this +guy so Theta is a function of mu + + align:start position:0% + + + + align:start position:0% + +is yeah right so we just computed that + + align:start position:0% +is yeah right so we just computed that + + + align:start position:0% +is yeah right so we just computed that +mu was B Prime of theta so it means that + + align:start position:0% +mu was B Prime of theta so it means that + + + align:start position:0% +mu was B Prime of theta so it means that +Theta is just B Prime inverse of mu okay + + align:start position:0% +Theta is just B Prime inverse of mu okay + + + align:start position:0% +Theta is just B Prime inverse of mu okay +so those two things are the same as far + + align:start position:0% +so those two things are the same as far + + + align:start position:0% +so those two things are the same as far +as we're concerned because because we + + align:start position:0% +as we're concerned because because we + + + align:start position:0% +as we're concerned because because we +know that b Prime is strictly increasing + + align:start position:0% +know that b Prime is strictly increasing + + + align:start position:0% +know that b Prime is strictly increasing +it's invertible so it's just a matter of + + align:start position:0% +it's invertible so it's just a matter of + + + align:start position:0% +it's invertible so it's just a matter of +reparameterization and we just can + + align:start position:0% +reparameterization and we just can + + + align:start position:0% +reparameterization and we just can +switch from one to the other whenever we + + align:start position:0% +switch from one to the other whenever we + + + align:start position:0% +switch from one to the other whenever we +want but why we go through me because + + align:start position:0% +want but why we go through me because + + + align:start position:0% +want but why we go through me because +you know so far for the entire semester + + align:start position:0% +you know so far for the entire semester + + + align:start position:0% +you know so far for the entire semester +I told you there's one parameter that's + + align:start position:0% +I told you there's one parameter that's + + + align:start position:0% +I told you there's one parameter that's +Theta does not have to be the mean and + + align:start position:0% +Theta does not have to be the mean and + + + align:start position:0% +Theta does not have to be the mean and +that's the parameter that we care about + + align:start position:0% +that's the parameter that we care about + + + align:start position:0% +that's the parameter that we care about +that's the one on which we want to do + + align:start position:0% +that's the one on which we want to do + + + align:start position:0% +that's the one on which we want to do +interference that's the one for which + + align:start position:0% +interference that's the one for which + + + align:start position:0% +interference that's the one for which +we're going to compute the Fisher + + align:start position:0% +we're going to compute the Fisher + + + align:start position:0% +we're going to compute the Fisher +information this was the parameter that + + align:start position:0% +information this was the parameter that + + + align:start position:0% +information this was the parameter that +was you know our object of worship and + + align:start position:0% +was you know our object of worship and + + + align:start position:0% +was you know our object of worship and +now I'm saying oh I'm going to have Mew + + align:start position:0% +now I'm saying oh I'm going to have Mew + + + align:start position:0% +now I'm saying oh I'm going to have Mew +that's like coming around and why we + + align:start position:0% +that's like coming around and why we + + + align:start position:0% +that's like coming around and why we +have me is because this is the Mew that + + align:start position:0% +have me is because this is the Mew that + + + align:start position:0% +have me is because this is the Mew that +we use to go to Beta all right so I can + + align:start position:0% +we use to go to Beta all right so I can + + + align:start position:0% +we use to go to Beta all right so I can +go freely from B Prime to uh uh from + + align:start position:0% +go freely from B Prime to uh uh from + + + align:start position:0% +go freely from B Prime to uh uh from +Theta to Mu using B prime or B Prime + + align:start position:0% +Theta to Mu using B prime or B Prime + + + align:start position:0% +Theta to Mu using B prime or B Prime +inverse and now I can go from me to uh + + align:start position:0% +inverse and now I can go from me to uh + + + align:start position:0% +inverse and now I can go from me to uh +beta because I have that g of mu of X is + + align:start position:0% +beta because I have that g of mu of X is + + + align:start position:0% +beta because I have that g of mu of X is +beta transpose + + align:start position:0% +beta transpose + + + align:start position:0% +beta transpose +X okay so in the end now this is going + + align:start position:0% +X okay so in the end now this is going + + + align:start position:0% +X okay so in the end now this is going +to be my object of worship this is going + + align:start position:0% +to be my object of worship this is going + + + align:start position:0% +to be my object of worship this is going +to be the parameter that matters because + + align:start position:0% +to be the parameter that matters because + + + align:start position:0% +to be the parameter that matters because +once I set beta I set everything else + + align:start position:0% +once I set beta I set everything else + + + align:start position:0% +once I set beta I set everything else +through this + + align:start position:0% +through this + + + align:start position:0% +through this +chain so the question is if I start + + align:start position:0% +chain so the question is if I start + + + align:start position:0% +chain so the question is if I start +stacking up this pile of parameters + + align:start position:0% +stacking up this pile of parameters + + + align:start position:0% +stacking up this pile of parameters +right so I start with my uh beta which + + align:start position:0% +right so I start with my uh beta which + + + align:start position:0% +right so I start with my uh beta which +in terms gives me a me which in terms + + align:start position:0% +in terms gives me a me which in terms + + + align:start position:0% +in terms gives me a me which in terms +gives me a Theta can I just have like a + + align:start position:0% +gives me a Theta can I just have like a + + + align:start position:0% +gives me a Theta can I just have like a +long + + align:start position:0% +long + + + align:start position:0% +long +streamlined uh uh can I what what what + + align:start position:0% +streamlined uh uh can I what what what + + + align:start position:0% +streamlined uh uh can I what what what +is the outcome when I actually start + + align:start position:0% +is the outcome when I actually start + + + align:start position:0% +is the outcome when I actually start +writing my likelihood not as a function + + align:start position:0% +writing my likelihood not as a function + + + align:start position:0% +writing my likelihood not as a function +of theta not as a function of mu but as + + align:start position:0% +of theta not as a function of mu but as + + + align:start position:0% +of theta not as a function of mu but as +a function of beta which is the one at + + align:start position:0% +a function of beta which is the one at + + + align:start position:0% +a function of beta which is the one at +the end of the chain okay and hopefully + + align:start position:0% +the end of the chain okay and hopefully + + + align:start position:0% +the end of the chain okay and hopefully +things are going to happen nicely and + + align:start position:0% +things are going to happen nicely and + + + align:start position:0% +things are going to happen nicely and +they might not + + align:start position:0% + + + + align:start position:0% + +yeah is G is G that's my link right G of + + align:start position:0% +yeah is G is G that's my link right G of + + + align:start position:0% +yeah is G is G that's my link right G of +mu of X now it's mu is a function of X + + align:start position:0% +mu of X now it's mu is a function of X + + + align:start position:0% +mu of X now it's mu is a function of X +because it's conditional on + + align:start position:0% + + + + align:start position:0% + +X okay so this is really Theta of + + align:start position:0% +X okay so this is really Theta of + + + align:start position:0% +X okay so this is really Theta of +X mu of X but B is not a function of X + + align:start position:0% +X mu of X but B is not a function of X + + + align:start position:0% +X mu of X but B is not a function of X +because it's just a there just something + + align:start position:0% +because it's just a there just something + + + align:start position:0% +because it's just a there just something +that tells me what the function of X + + align:start position:0% +that tells me what the function of X + + + align:start position:0% +that tells me what the function of X +is m + + align:start position:0% +is m + + + align:start position:0% +is m +new is the conditional expectation of Y + + align:start position:0% +new is the conditional expectation of Y + + + align:start position:0% +new is the conditional expectation of Y +given X it has actually a fancy name in + + align:start position:0% +given X it has actually a fancy name in + + + align:start position:0% +given X it has actually a fancy name in +the statistics literature it's + + align:start position:0% +the statistics literature it's + + + align:start position:0% +the statistics literature it's +called anybody knows the name of this + + align:start position:0% +called anybody knows the name of this + + + align:start position:0% +called anybody knows the name of this +function U of X which is the conditional + + align:start position:0% +function U of X which is the conditional + + + align:start position:0% +function U of X which is the conditional +expectation of Y given + + align:start position:0% + + + + align:start position:0% + +X that's the regression function that's + + align:start position:0% +X that's the regression function that's + + + align:start position:0% +X that's the regression function that's +actual definition if I tell you what is + + align:start position:0% +actual definition if I tell you what is + + + align:start position:0% +actual definition if I tell you what is +the definition of the regression + + align:start position:0% +the definition of the regression + + + align:start position:0% +the definition of the regression +function that's just the conditional + + align:start position:0% +function that's just the conditional + + + align:start position:0% +function that's just the conditional +expectation of y + + align:start position:0% +expectation of y + + + align:start position:0% +expectation of y +x and uh just you know I could look at + + align:start position:0% +x and uh just you know I could look at + + + align:start position:0% +x and uh just you know I could look at +any property of the conditional + + align:start position:0% +any property of the conditional + + + align:start position:0% +any property of the conditional +distribution of Y given X I could look + + align:start position:0% +distribution of Y given X I could look + + + align:start position:0% +distribution of Y given X I could look +at the conditional 95th percentile I + + align:start position:0% +at the conditional 95th percentile I + + + align:start position:0% +at the conditional 95th percentile I +could look at the conditional median I + + align:start position:0% +could look at the conditional median I + + + align:start position:0% +could look at the conditional median I +could look at the conditional inter + + align:start position:0% +could look at the conditional inter + + + align:start position:0% +could look at the conditional inter +profile range could look at the + + align:start position:0% +profile range could look at the + + + align:start position:0% +profile range could look at the +conditional variance but I decide to + + align:start position:0% +conditional variance but I decide to + + + align:start position:0% +conditional variance but I decide to +look at the conditional expectation + + align:start position:0% +look at the conditional expectation + + + align:start position:0% +look at the conditional expectation +which is uh called the regression + + align:start position:0% +which is uh called the regression + + + align:start position:0% +which is uh called the regression +function okay + + align:start position:0% + + + + align:start position:0% + +yes oh there's no transpose here uh + + align:start position:0% +yes oh there's no transpose here uh + + + align:start position:0% +yes oh there's no transpose here uh +actually only Victor Manuel uses Prime + + align:start position:0% +actually only Victor Manuel uses Prime + + + align:start position:0% +actually only Victor Manuel uses Prime +for transpose and I found it confusing + + align:start position:0% +for transpose and I found it confusing + + + align:start position:0% +for transpose and I found it confusing +with the derivatives so primes here is + + align:start position:0% +with the derivatives so primes here is + + + align:start position:0% +with the derivatives so primes here is +only a + + align:start position:0% + + + + align:start position:0% + +derivative oh yeah sorry beta transpose + + align:start position:0% +derivative oh yeah sorry beta transpose + + + align:start position:0% +derivative oh yeah sorry beta transpose +X sorry I thought you okay so you said + + align:start position:0% +X sorry I thought you okay so you said + + + align:start position:0% +X sorry I thought you okay so you said +what I said that g of mu of X is beta + + align:start position:0% +what I said that g of mu of X is beta + + + align:start position:0% +what I said that g of mu of X is beta +transpose + + align:start position:0% + + + + align:start position:0% + +X isn't that the same + + align:start position:0% +X isn't that the same + + + align:start position:0% +X isn't that the same +thing those X is a vector here right so + + align:start position:0% +thing those X is a vector here right so + + + align:start position:0% +thing those X is a vector here right so +X trans beta and beta transpose X are + + align:start position:0% +X trans beta and beta transpose X are + + + align:start position:0% +X trans beta and beta transpose X are +the same + + align:start position:0% + + + + align:start position:0% + +thing right so beta is looks like this x + + align:start position:0% +thing right so beta is looks like this x + + + align:start position:0% +thing right so beta is looks like this x +looks like this so it's just simple + + align:start position:0% +looks like this so it's just simple + + + align:start position:0% +looks like this so it's just simple +simple + + align:start position:0% + + + + align:start position:0% + +number yeah you're right when I I'm + + align:start position:0% +number yeah you're right when I I'm + + + align:start position:0% +number yeah you're right when I I'm +going to start to look at matrices I'm + + align:start position:0% +going to start to look at matrices I'm + + + align:start position:0% +going to start to look at matrices I'm +going to have to be slightly more + + align:start position:0% +going to have to be slightly more + + + align:start position:0% +going to have to be slightly more +careful when I do + + align:start position:0% +careful when I do + + + align:start position:0% +careful when I do +this okay so let's do the reverse + + align:start position:0% +this okay so let's do the reverse + + + align:start position:0% +this okay so let's do the reverse +engineering I'm giving you data from + + align:start position:0% +engineering I'm giving you data from + + + align:start position:0% +engineering I'm giving you data from +this data hopefully you should be able + + align:start position:0% +this data hopefully you should be able + + + align:start position:0% +this data hopefully you should be able +to get what the conditional if I give + + align:start position:0% +to get what the conditional if I give + + + align:start position:0% +to get what the conditional if I give +you an infinite amount of data you would + + align:start position:0% +you an infinite amount of data you would + + + align:start position:0% +you an infinite amount of data you would +know exactly what the of pairs X Y you + + align:start position:0% +know exactly what the of pairs X Y you + + + align:start position:0% +know exactly what the of pairs X Y you +would know exactly what the conditional + + align:start position:0% +would know exactly what the conditional + + + align:start position:0% +would know exactly what the conditional +distribution of Y given X + + align:start position:0% +distribution of Y given X + + + align:start position:0% +distribution of Y given X +is and uh in particular you would know + + align:start position:0% +is and uh in particular you would know + + + align:start position:0% +is and uh in particular you would know +what the conditional expectation of Y + + align:start position:0% +what the conditional expectation of Y + + + align:start position:0% +what the conditional expectation of Y +given X is which means that you would + + align:start position:0% +given X is which means that you would + + + align:start position:0% +given X is which means that you would +know mu which means that you would know + + align:start position:0% +know mu which means that you would know + + + align:start position:0% +know mu which means that you would know +Theta which means that you would know + + align:start position:0% +Theta which means that you would know + + + align:start position:0% +Theta which means that you would know +beta okay now when I have a finite + + align:start position:0% +beta okay now when I have a finite + + + align:start position:0% +beta okay now when I have a finite +number of observations I'm going to try + + align:start position:0% +number of observations I'm going to try + + + align:start position:0% +number of observations I'm going to try +to estimate mu of X but really I'm going + + align:start position:0% +to estimate mu of X but really I'm going + + + align:start position:0% +to estimate mu of X but really I'm going +to go the other round way around because + + align:start position:0% +to go the other round way around because + + + align:start position:0% +to go the other round way around because +the fact that I assume specific that mu + + align:start position:0% +the fact that I assume specific that mu + + + align:start position:0% +the fact that I assume specific that mu +of X is of the form G of mu of X is X + + align:start position:0% +of X is of the form G of mu of X is X + + + align:start position:0% +of X is of the form G of mu of X is X +transpose beta then that means that I + + align:start position:0% +transpose beta then that means that I + + + align:start position:0% +transpose beta then that means that I +only have to estimate beta which is a + + align:start position:0% +only have to estimate beta which is a + + + align:start position:0% +only have to estimate beta which is a +much simpler object than the entire + + align:start position:0% +much simpler object than the entire + + + align:start position:0% +much simpler object than the entire +regression function okay and so that's + + align:start position:0% +regression function okay and so that's + + + align:start position:0% +regression function okay and so that's +what I'm going to go for I'm going to + + align:start position:0% +what I'm going to go for I'm going to + + + align:start position:0% +what I'm going to go for I'm going to +try to represent the likelihood the log + + align:start position:0% +try to represent the likelihood the log + + + align:start position:0% +try to represent the likelihood the log +likelihood of my data as a function not + + align:start position:0% +likelihood of my data as a function not + + + align:start position:0% +likelihood of my data as a function not +of theta not of mu but of beta and then + + align:start position:0% +of theta not of mu but of beta and then + + + align:start position:0% +of theta not of mu but of beta and then +maximize that guy all right so now + + align:start position:0% +maximize that guy all right so now + + + align:start position:0% +maximize that guy all right so now +rather than thinking of just one + + align:start position:0% +rather than thinking of just one + + + align:start position:0% +rather than thinking of just one +observation I'm going to have a bunch of + + align:start position:0% +observation I'm going to have a bunch of + + + align:start position:0% +observation I'm going to have a bunch of +observations and every time you see here + + align:start position:0% +observations and every time you see here + + + align:start position:0% +observations and every time you see here +so this might actually look a little + + align:start position:0% +so this might actually look a little + + + align:start position:0% +so this might actually look a little +confusing but uh let's just make sure + + align:start position:0% +confusing but uh let's just make sure + + + align:start position:0% +confusing but uh let's just make sure +that we understand each other before we + + align:start position:0% +that we understand each other before we + + + align:start position:0% +that we understand each other before we +go any further so I'm going to have + + align:start position:0% + + + + align:start position:0% + +observations X1 + + align:start position:0% +observations X1 + + + align:start position:0% +observations X1 +y1 all the way to xn YN just like in a + + align:start position:0% +y1 all the way to xn YN just like in a + + + align:start position:0% +y1 all the way to xn YN just like in a +natural regression problem except that + + align:start position:0% +natural regression problem except that + + + align:start position:0% +natural regression problem except that +here my y's might be zero1 valued they + + align:start position:0% +here my y's might be zero1 valued they + + + align:start position:0% +here my y's might be zero1 valued they +might be positive value they might be + + align:start position:0% +might be positive value they might be + + + align:start position:0% +might be positive value they might be +exponential they might be anything in + + align:start position:0% +exponential they might be anything in + + + align:start position:0% +exponential they might be anything in +the canonical exponential family and + + align:start position:0% +the canonical exponential family and + + + align:start position:0% +the canonical exponential family and +um okay so I have this uh I have this + + align:start position:0% +um okay so I have this uh I have this + + + align:start position:0% +um okay so I have this uh I have this +thing and now what I have is that so my + + align:start position:0% +thing and now what I have is that so my + + + align:start position:0% +thing and now what I have is that so my +observations are X1 y1 xn YN and what I + + align:start position:0% +observations are X1 y1 xn YN and what I + + + align:start position:0% +observations are X1 y1 xn YN and what I +want is that uh I'm going to talk about + + align:start position:0% +want is that uh I'm going to talk about + + + align:start position:0% +want is that uh I'm going to talk about +I'm going to assume that the conditional + + align:start position:0% +I'm going to assume that the conditional + + + align:start position:0% +I'm going to assume that the conditional +expectation of Yi given X + + align:start position:0% +expectation of Yi given X + + + align:start position:0% +expectation of Yi given X +sorry yeah the conditional the + + align:start position:0% +sorry yeah the conditional the + + + align:start position:0% +sorry yeah the conditional the +conditional distribution of Yi given XI + + align:start position:0% +conditional distribution of Yi given XI + + + align:start position:0% +conditional distribution of Yi given XI +is something that has density + + align:start position:0% + + + + align:start position:0% + +did I put an eye on white + + align:start position:0% + + + + align:start position:0% + +yeah I'm not going to deal with the FI + + align:start position:0% +yeah I'm not going to deal with the FI + + + align:start position:0% +yeah I'm not going to deal with the FI +and the C now and what why do I have + + align:start position:0% +and the C now and what why do I have + + + align:start position:0% +and the C now and what why do I have +Theta I and not Theta is because Theta I + + align:start position:0% +Theta I and not Theta is because Theta I + + + align:start position:0% +Theta I and not Theta is because Theta I +is really a function of the of um uh + + align:start position:0% + + + + align:start position:0% + +of x i right so it's really Theta I of x + + align:start position:0% +of x i right so it's really Theta I of x + + + align:start position:0% +of x i right so it's really Theta I of x +i but what do I know about Theta I of XI + + align:start position:0% +i but what do I know about Theta I of XI + + + align:start position:0% +i but what do I know about Theta I of XI +it's actually equal + + align:start position:0% +it's actually equal + + + align:start position:0% +it's actually equal +to um B I did this error twice B Prime + + align:start position:0% +to um B I did this error twice B Prime + + + align:start position:0% +to um B I did this error twice B Prime +inverse of mu of XI + + align:start position:0% + + + + align:start position:0% + +okay and also know that this thing is + + align:start position:0% +okay and also know that this thing is + + + align:start position:0% +okay and also know that this thing is +actually I'm going to assume that this + + align:start position:0% +actually I'm going to assume that this + + + align:start position:0% +actually I'm going to assume that this +is of the form beta transpose XI okay + + align:start position:0% +is of the form beta transpose XI okay + + + align:start position:0% +is of the form beta transpose XI okay +and this is why I have a Theta I is + + align:start position:0% +and this is why I have a Theta I is + + + align:start position:0% +and this is why I have a Theta I is +because this Theta I is a function of XI + + align:start position:0% +because this Theta I is a function of XI + + + align:start position:0% +because this Theta I is a function of XI +and I'm going to assume a very simple + + align:start position:0% +and I'm going to assume a very simple + + + align:start position:0% +and I'm going to assume a very simple +form for this + + align:start position:0% + + + + align:start position:0% + +thing sorry sorry sorry sorry that's uh + + align:start position:0% +thing sorry sorry sorry sorry that's uh + + + align:start position:0% +thing sorry sorry sorry sorry that's uh +yeah sorry I should not write it like + + align:start position:0% +yeah sorry I should not write it like + + + align:start position:0% +yeah sorry I should not write it like +this this is only when I have the + + align:start position:0% +this this is only when I have the + + + align:start position:0% +this this is only when I have the +canonical length so this is actually + + align:start position:0% +canonical length so this is actually + + + align:start position:0% +canonical length so this is actually +equal to B Prime inverse of G of X I + + align:start position:0% +equal to B Prime inverse of G of X I + + + align:start position:0% +equal to B Prime inverse of G of X I +transpose + + align:start position:0% +transpose + + + align:start position:0% +transpose +Beta And when I have the canonical + + align:start position:0% +Beta And when I have the canonical + + + align:start position:0% +Beta And when I have the canonical +link sorry G inverse those two things + + align:start position:0% +link sorry G inverse those two things + + + align:start position:0% +link sorry G inverse those two things +are actually canceling each + + align:start position:0% +are actually canceling each + + + align:start position:0% +are actually canceling each +other + + align:start position:0% +other + + + align:start position:0% +other +okay so as before I'm going to stack + + align:start position:0% +okay so as before I'm going to stack + + + align:start position:0% +okay so as before I'm going to stack +everything into some uh well actually + + align:start position:0% +everything into some uh well actually + + + align:start position:0% +everything into some uh well actually +I'm not going to stack anything for the + + align:start position:0% +I'm not going to stack anything for the + + + align:start position:0% +I'm not going to stack anything for the +moment I'm just going to give you a peek + + align:start position:0% +moment I'm just going to give you a peek + + + align:start position:0% +moment I'm just going to give you a peek +at what's happening next week uh rather + + align:start position:0% +at what's happening next week uh rather + + + align:start position:0% +at what's happening next week uh rather +than just manipulating uh the data all + + align:start position:0% +than just manipulating uh the data all + + + align:start position:0% +than just manipulating uh the data all +right + + align:start position:0% +right + + + align:start position:0% +right +so here is how we're going to proceed at + + align:start position:0% +so here is how we're going to proceed at + + + align:start position:0% +so here is how we're going to proceed at +this + + align:start position:0% +this + + + align:start position:0% +this +point well now I'm going to want to + + align:start position:0% +point well now I'm going to want to + + + align:start position:0% +point well now I'm going to want to +write my likelihood function not as a + + align:start position:0% +write my likelihood function not as a + + + align:start position:0% +write my likelihood function not as a +function of theta but as a function of + + align:start position:0% +function of theta but as a function of + + + align:start position:0% +function of theta but as a function of +beta because that that's the parameter + + align:start position:0% +beta because that that's the parameter + + + align:start position:0% +beta because that that's the parameter +I'm actually trying to maximize + + align:start position:0% +I'm actually trying to maximize + + + align:start position:0% +I'm actually trying to maximize +right so if I have a link so this thing + + align:start position:0% +right so if I have a link so this thing + + + align:start position:0% +right so if I have a link so this thing +that matters here I'm going to call + + align:start position:0% + + + + align:start position:0% + +H by definition this is going to be h of + + align:start position:0% +H by definition this is going to be h of + + + align:start position:0% +H by definition this is going to be h of +X I transpose beta Helena you have a + + align:start position:0% +X I transpose beta Helena you have a + + + align:start position:0% +X I transpose beta Helena you have a +question okay so right so this is just + + align:start position:0% +question okay so right so this is just + + + align:start position:0% +question okay so right so this is just +the all the things that we know right + + align:start position:0% +the all the things that we know right + + + align:start position:0% +the all the things that we know right +Theta is just the by definition of the + + align:start position:0% +Theta is just the by definition of the + + + align:start position:0% +Theta is just the by definition of the +fact that mu is B Prime of theta the + + align:start position:0% +fact that mu is B Prime of theta the + + + align:start position:0% +fact that mu is B Prime of theta the +mean is B Prime of theta it means that + + align:start position:0% +mean is B Prime of theta it means that + + + align:start position:0% +mean is B Prime of theta it means that +Theta is B Prime inverse of mu and then + + align:start position:0% +Theta is B Prime inverse of mu and then + + + align:start position:0% +Theta is B Prime inverse of mu and then +uh mu is modeled from the systematic + + align:start position:0% +uh mu is modeled from the systematic + + + align:start position:0% +uh mu is modeled from the systematic +component G of mu is X I transpose beta + + align:start position:0% +component G of mu is X I transpose beta + + + align:start position:0% +component G of mu is X I transpose beta +so this is G inverse of X I transpose + + align:start position:0% +so this is G inverse of X I transpose + + + align:start position:0% +so this is G inverse of X I transpose +beta so I want to have B Prime IND + + align:start position:0% +beta so I want to have B Prime IND + + + align:start position:0% +beta so I want to have B Prime IND +inverse of G Prime of G inverse this + + align:start position:0% +inverse of G Prime of G inverse this + + + align:start position:0% +inverse of G Prime of G inverse this +function is a bit annoying to say so I'm + + align:start position:0% +function is a bit annoying to say so I'm + + + align:start position:0% +function is a bit annoying to say so I'm +just going to call it + + align:start position:0% +just going to call it + + + align:start position:0% +just going to call it +h and when I do the composition of two + + align:start position:0% +h and when I do the composition of two + + + align:start position:0% +h and when I do the composition of two +inverse it's the inverse of the + + align:start position:0% +inverse it's the inverse of the + + + align:start position:0% +inverse it's the inverse of the +composition of those two things in the + + align:start position:0% +composition of those two things in the + + + align:start position:0% +composition of those two things in the +reverse order so H is really the inverse + + align:start position:0% +reverse order so H is really the inverse + + + align:start position:0% +reverse order so H is really the inverse +of G composed with B Prime G of B Prime + + align:start position:0% +of G composed with B Prime G of B Prime + + + align:start position:0% +of G composed with B Prime G of B Prime +inverse okay and now if I have the + + align:start position:0% +inverse okay and now if I have the + + + align:start position:0% +inverse okay and now if I have the +canonical length since I know that g is + + align:start position:0% +canonical length since I know that g is + + + align:start position:0% +canonical length since I know that g is +B Prime inverse this is really just the + + align:start position:0% +B Prime inverse this is really just the + + + align:start position:0% +B Prime inverse this is really just the +identity so as you can imagine + + align:start position:0% +identity so as you can imagine + + + align:start position:0% +identity so as you can imagine +this entire + + align:start position:0% +this entire + + + align:start position:0% +this entire +thing which is actually quite + + align:start position:0% +thing which is actually quite + + + align:start position:0% +thing which is actually quite +complicated would just say oh this thing + + align:start position:0% +complicated would just say oh this thing + + + align:start position:0% +complicated would just say oh this thing +actually does not show up when I have + + align:start position:0% +actually does not show up when I have + + + align:start position:0% +actually does not show up when I have +the canonical link I really just have + + align:start position:0% +the canonical link I really just have + + + align:start position:0% +the canonical link I really just have +that Theta I can be replaced by XI of + + align:start position:0% +that Theta I can be replaced by XI of + + + align:start position:0% +that Theta I can be replaced by XI of +beta so think about going back to this + + align:start position:0% +beta so think about going back to this + + + align:start position:0% +beta so think about going back to this +guy here now beta theta becomes only XI + + align:start position:0% +guy here now beta theta becomes only XI + + + align:start position:0% +guy here now beta theta becomes only XI +transpose + + align:start position:0% +transpose + + + align:start position:0% +transpose +beta that's going to be much more simple + + align:start position:0% +beta that's going to be much more simple + + + align:start position:0% +beta that's going to be much more simple +simple to optimize because remember when + + align:start position:0% +simple to optimize because remember when + + + align:start position:0% +simple to optimize because remember when +I'm going to do log likelihood this + + align:start position:0% +I'm going to do log likelihood this + + + align:start position:0% +I'm going to do log likelihood this +thing is going to go away I'm going to + + align:start position:0% +thing is going to go away I'm going to + + + align:start position:0% +thing is going to go away I'm going to +sum those guys and so what I'm going to + + align:start position:0% +sum those guys and so what I'm going to + + + align:start position:0% +sum those guys and so what I'm going to +have is something which is essentially + + align:start position:0% +have is something which is essentially + + + align:start position:0% +have is something which is essentially +linear in beta and then I'm going to + + align:start position:0% +linear in beta and then I'm going to + + + align:start position:0% +linear in beta and then I'm going to +have this minus B which is just minus + + align:start position:0% +have this minus B which is just minus + + + align:start position:0% +have this minus B which is just minus +the sum of convex functions of beta so + + align:start position:0% +the sum of convex functions of beta so + + + align:start position:0% +the sum of convex functions of beta so +I'm going to have to bring in the tools + + align:start position:0% +I'm going to have to bring in the tools + + + align:start position:0% +I'm going to have to bring in the tools +of convex optimization now it's not just + + align:start position:0% +of convex optimization now it's not just + + + align:start position:0% +of convex optimization now it's not just +going to be take the gradient set it to + + align:start position:0% +going to be take the gradient set it to + + + align:start position:0% +going to be take the gradient set it to +zero it's going to be more complicated + + align:start position:0% +zero it's going to be more complicated + + + align:start position:0% +zero it's going to be more complicated +to do that I'm going to have to do that + + align:start position:0% +to do that I'm going to have to do that + + + align:start position:0% +to do that I'm going to have to do that +in an iterative fashion and so that's + + align:start position:0% +in an iterative fashion and so that's + + + align:start position:0% +in an iterative fashion and so that's +what I'm telling you when you look at + + align:start position:0% +what I'm telling you when you look at + + + align:start position:0% +what I'm telling you when you look at +your log likelihood for all those + + align:start position:0% +your log likelihood for all those + + + align:start position:0% +your log likelihood for all those +functions you sum the exponential goes + + align:start position:0% +functions you sum the exponential goes + + + align:start position:0% +functions you sum the exponential goes +away because you had the log and then + + align:start position:0% +away because you had the log and then + + + align:start position:0% +away because you had the log and then +you have all these things here I kept + + align:start position:0% +you have all these things here I kept + + + align:start position:0% +you have all these things here I kept +the B I kept the H but if H is the + + align:start position:0% +the B I kept the H but if H is the + + + align:start position:0% +the B I kept the H but if H is the +identity this is the linear function the + + align:start position:0% +identity this is the linear function the + + + align:start position:0% +identity this is the linear function the +linear part y i * X I transpose beta + + align:start position:0% +linear part y i * X I transpose beta + + + align:start position:0% +linear part y i * X I transpose beta +minus B of my Theta which is now only X + + align:start position:0% +minus B of my Theta which is now only X + + + align:start position:0% +minus B of my Theta which is now only X +I transpose beta and that's the function + + align:start position:0% +I transpose beta and that's the function + + + align:start position:0% +I transpose beta and that's the function +I want to maximize in + + align:start position:0% +I want to maximize in + + + align:start position:0% +I want to maximize in +beta + + align:start position:0% +beta + + + align:start position:0% +beta +okay that's a simple I mean it's a + + align:start position:0% +okay that's a simple I mean it's a + + + align:start position:0% +okay that's a simple I mean it's a +complex function when I know what B is I + + align:start position:0% +complex function when I know what B is I + + + align:start position:0% +complex function when I know what B is I +have an explicit formula formula for + + align:start position:0% +have an explicit formula formula for + + + align:start position:0% +have an explicit formula formula for +this and I want to just bring in some + + align:start position:0% +this and I want to just bring in some + + + align:start position:0% +this and I want to just bring in some +optimization and uh that's uh what we're + + align:start position:0% +optimization and uh that's uh what we're + + + align:start position:0% +optimization and uh that's uh what we're +going to do and we're going to see three + + align:start position:0% +going to do and we're going to see three + + + align:start position:0% +going to do and we're going to see three +different methods which are really + + align:start position:0% +different methods which are really + + + align:start position:0% +different methods which are really +basically the same method it's something + + align:start position:0% +basically the same method it's something + + + align:start position:0% +basically the same method it's something +which is B based on it's just a + + align:start position:0% +which is B based on it's just a + + + align:start position:0% +which is B based on it's just a +adaptation or specialization of the + + align:start position:0% +adaptation or specialization of the + + + align:start position:0% +adaptation or specialization of the +So-Cal Newton rapon method which is + + align:start position:0% +So-Cal Newton rapon method which is + + + align:start position:0% +So-Cal Newton rapon method which is +essentially telling you do iterative + + align:start position:0% +essentially telling you do iterative + + + align:start position:0% +essentially telling you do iterative +local quadratic approximation to your + + align:start position:0% +local quadratic approximation to your + + + align:start position:0% +local quadratic approximation to your +function so second order tiller + + align:start position:0% +function so second order tiller + + + align:start position:0% +function so second order tiller +expansion minimize this guy and then do + + align:start position:0% +expansion minimize this guy and then do + + + align:start position:0% +expansion minimize this guy and then do +it again from where you were okay and uh + + align:start position:0% +it again from where you were okay and uh + + + align:start position:0% +it again from where you were okay and uh +we'll see that this can be actually + + align:start position:0% +we'll see that this can be actually + + + align:start position:0% +we'll see that this can be actually +implemented using what's called + + align:start position:0% +implemented using what's called + + + align:start position:0% +implemented using what's called +iteratively reweighted Le squares which + + align:start position:0% +iteratively reweighted Le squares which + + + align:start position:0% +iteratively reweighted Le squares which +means that every step since it's just a + + align:start position:0% +means that every step since it's just a + + + align:start position:0% +means that every step since it's just a +quadratic it's going to be just squares + + align:start position:0% +quadratic it's going to be just squares + + + align:start position:0% +quadratic it's going to be just squares +in there every step can actually be + + align:start position:0% +in there every step can actually be + + + align:start position:0% +in there every step can actually be +solved by using awaited uh e squares + + align:start position:0% +solved by using awaited uh e squares + + + align:start position:0% +solved by using awaited uh e squares +version of the problem okay so uh I'm + + align:start position:0% +version of the problem okay so uh I'm + + + align:start position:0% +version of the problem okay so uh I'm +going to stop here for today so we'll + + align:start position:0% +going to stop here for today so we'll + + + align:start position:0% +going to stop here for today so we'll +continue and uh uh probably not finish + + align:start position:0% +continue and uh uh probably not finish + + + align:start position:0% +continue and uh uh probably not finish +this chapter but finish next week and uh + + align:start position:0% +this chapter but finish next week and uh + + + align:start position:0% +this chapter but finish next week and uh +and then I think there's only one + + align:start position:0% +and then I think there's only one + + + align:start position:0% +and then I think there's only one +lecture um actually for the last lecture + + align:start position:0% +lecture um actually for the last lecture + + + align:start position:0% +lecture um actually for the last lecture +what do you guys want to + + align:start position:0% + + + + align:start position:0% + +do do you want to have donuts and cider + + align:start position:0% +do do you want to have donuts and cider + + + align:start position:0% +do do you want to have donuts and cider +do you wanna do you want to just have + + align:start position:0% +do you wanna do you want to just have + + + align:start position:0% +do you wanna do you want to just have +like some more like uh outlooking uh uh + + align:start position:0% +like some more like uh outlooking uh uh + + + align:start position:0% +like some more like uh outlooking uh uh +lecture on you know what's uh happening + + align:start position:0% +lecture on you know what's uh happening + + + align:start position:0% +lecture on you know what's uh happening +post 1975 in + + align:start position:0% +post 1975 in + + + align:start position:0% +post 1975 in +statistics uh do you want to have a a + + align:start position:0% +statistics uh do you want to have a a + + + align:start position:0% +statistics uh do you want to have a a +review for the final + + align:start position:0% +review for the final + + + align:start position:0% +review for the final +exam pragmatic people all + + align:start position:0% + + + + align:start position:0% + +right you want to do interesting advanc + + align:start position:0% +right you want to do interesting advanc + + + align:start position:0% +right you want to do interesting advanc +for for the last lecture yeah so that's + + align:start position:0% +for for the last lecture yeah so that's + + + align:start position:0% +for for the last lecture yeah so that's +sort + + align:start position:0% +sort + + + align:start position:0% +sort +of yeah the thing is I think uh so this + + align:start position:0% +of yeah the thing is I think uh so this + + + align:start position:0% +of yeah the thing is I think uh so this +there's two that that's basically what + + align:start position:0% +there's two that that's basically what + + + align:start position:0% +there's two that that's basically what +I'm asking right interesting topics + + align:start position:0% +I'm asking right interesting topics + + + align:start position:0% +I'm asking right interesting topics +versus uh uh let's like ask me any + + align:start position:0% +versus uh uh let's like ask me any + + + align:start position:0% +versus uh uh let's like ask me any +question you want those questions can be + + align:start position:0% +question you want those questions can be + + + align:start position:0% +question you want those questions can be +about interesting Advanced topics though + + align:start position:0% +about interesting Advanced topics though + + + align:start position:0% +about interesting Advanced topics though +like what are interesting Advanced + + align:start position:0% +like what are interesting Advanced + + + align:start position:0% +like what are interesting Advanced +topics I'm + + align:start position:0% +topics I'm + + + align:start position:0% +topics I'm +sorry yeah yeah we can always do the + + align:start position:0% +sorry yeah yeah we can always do the + + + align:start position:0% +sorry yeah yeah we can always do the +donuts we can + + align:start position:0% +donuts we can + + + align:start position:0% +donuts we can +[Laughter] + + align:start position:0% +[Laughter] + + + align:start position:0% +[Laughter] +always all right we'll do that all right + + align:start position:0% +always all right we'll do that all right + + + align:start position:0% +always all right we'll do that all right +see you guys have a good weekend \ No newline at end of file diff --git a/mcwwXuYkBGY.txt b/mcwwXuYkBGY.txt new file mode 100644 index 0000000000000000000000000000000000000000..f3f763e782241e9c284e906f37218b4c5061f63e --- /dev/null +++ b/mcwwXuYkBGY.txt @@ -0,0 +1,9139 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +to view additional materials from + + align:start position:0% +to view additional materials from + + + align:start position:0% +to view additional materials from +hundreds of MIT courses visit MIT open + + align:start position:0% +hundreds of MIT courses visit MIT open + + + align:start position:0% +hundreds of MIT courses visit MIT open +courseware at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu what I want to do today is + + align:start position:0% +ocw.mit.edu what I want to do today is + + + align:start position:0% +ocw.mit.edu what I want to do today is +uh finish uh second installment of phase + + align:start position:0% +uh finish uh second installment of phase + + + align:start position:0% +uh finish uh second installment of phase +diagrams last day we looked at un phase + + align:start position:0% +diagrams last day we looked at un phase + + + align:start position:0% +diagrams last day we looked at un phase +diagrams that is to say single component + + align:start position:0% +diagrams that is to say single component + + + align:start position:0% +diagrams that is to say single component +so that meant all we had to do was worry + + align:start position:0% +so that meant all we had to do was worry + + + align:start position:0% +so that meant all we had to do was worry +about uh pressure versus temperature + + align:start position:0% +about uh pressure versus temperature + + + align:start position:0% +about uh pressure versus temperature +because everything's of simple + + align:start position:0% +because everything's of simple + + + align:start position:0% +because everything's of simple +composition and uh I've got up here on + + align:start position:0% +composition and uh I've got up here on + + + align:start position:0% +composition and uh I've got up here on +the uh uh display uh phase diagram of + + align:start position:0% +the uh uh display uh phase diagram of + + + align:start position:0% +the uh uh display uh phase diagram of +water which we looked at last day and + + align:start position:0% +water which we looked at last day and + + + align:start position:0% +water which we looked at last day and +I've redrawn it here for uh convenience + + align:start position:0% +I've redrawn it here for uh convenience + + + align:start position:0% +I've redrawn it here for uh convenience +and I just wanted to draw your attention + + align:start position:0% +and I just wanted to draw your attention + + + align:start position:0% +and I just wanted to draw your attention +to several things we're looking at how + + align:start position:0% +to several things we're looking at how + + + align:start position:0% +to several things we're looking at how +the stability of the different phases of + + align:start position:0% +the stability of the different phases of + + + align:start position:0% +the stability of the different phases of +water varies with pressure and + + align:start position:0% +water varies with pressure and + + + align:start position:0% +water varies with pressure and +temperature I've drawn the solid region + + align:start position:0% +temperature I've drawn the solid region + + + align:start position:0% +temperature I've drawn the solid region +over here single phase liquid region up + + align:start position:0% +over here single phase liquid region up + + + align:start position:0% +over here single phase liquid region up +here single phase and Vapor region over + + align:start position:0% +here single phase and Vapor region over + + + align:start position:0% +here single phase and Vapor region over +here single phase and at some point we + + align:start position:0% +here single phase and at some point we + + + align:start position:0% +here single phase and at some point we +Transit from solid to liquid and it + + align:start position:0% +Transit from solid to liquid and it + + + align:start position:0% +Transit from solid to liquid and it +doesn't happen at a single point it + + align:start position:0% +doesn't happen at a single point it + + + align:start position:0% +doesn't happen at a single point it +happens over a range of temperatures and + + align:start position:0% +happens over a range of temperatures and + + + align:start position:0% +happens over a range of temperatures and +pressures along this line which is + + align:start position:0% +pressures along this line which is + + + align:start position:0% +pressures along this line which is +called the coexistence Curve so whenever + + align:start position:0% +called the coexistence Curve so whenever + + + align:start position:0% +called the coexistence Curve so whenever +you have two phases in equilibrium uh + + align:start position:0% +you have two phases in equilibrium uh + + + align:start position:0% +you have two phases in equilibrium uh +they Define a coexistence curve and so + + align:start position:0% +they Define a coexistence curve and so + + + align:start position:0% +they Define a coexistence curve and so +here's the solid liquid coexistence curv + + align:start position:0% +here's the solid liquid coexistence curv + + + align:start position:0% +here's the solid liquid coexistence curv +liquid vapor and solid Vapor um we saw + + align:start position:0% +liquid vapor and solid Vapor um we saw + + + align:start position:0% +liquid vapor and solid Vapor um we saw +what happens at our life which is the + + align:start position:0% +what happens at our life which is the + + + align:start position:0% +what happens at our life which is the +one atmosphere isobar this equilibrium + + align:start position:0% +one atmosphere isobar this equilibrium + + + align:start position:0% +one atmosphere isobar this equilibrium +solid liquid that's ice water is at 0 + + align:start position:0% +solid liquid that's ice water is at 0 + + + align:start position:0% +solid liquid that's ice water is at 0 +degrees C and the normal boiling point + + align:start position:0% +degrees C and the normal boiling point + + + align:start position:0% +degrees C and the normal boiling point +that is to say one atmosphere applied + + align:start position:0% +that is to say one atmosphere applied + + + align:start position:0% +that is to say one atmosphere applied +pressure which is nominally sea level is + + align:start position:0% +pressure which is nominally sea level is + + + align:start position:0% +pressure which is nominally sea level is +uh 100° C + + align:start position:0% +uh 100° C + + + align:start position:0% +uh 100° C +and we saw how boiling point varies with + + align:start position:0% +and we saw how boiling point varies with + + + align:start position:0% +and we saw how boiling point varies with +applied pressure and that is defined + + align:start position:0% +applied pressure and that is defined + + + align:start position:0% +applied pressure and that is defined +along this coexistence curve um the + + align:start position:0% +along this coexistence curve um the + + + align:start position:0% +along this coexistence curve um the +other thing to note is when the three + + align:start position:0% +other thing to note is when the three + + + align:start position:0% +other thing to note is when the three +coexistence curves intersect we have + + align:start position:0% +coexistence curves intersect we have + + + align:start position:0% +coexistence curves intersect we have +this unique unique set of circumstances + + align:start position:0% +this unique unique set of circumstances + + + align:start position:0% +this unique unique set of circumstances +called the triple point where all three + + align:start position:0% +called the triple point where all three + + + align:start position:0% +called the triple point where all three +phases coexist and they coexist at only + + align:start position:0% +phases coexist and they coexist at only + + + align:start position:0% +phases coexist and they coexist at only +one point that is to say one temperature + + align:start position:0% +one point that is to say one temperature + + + align:start position:0% +one point that is to say one temperature +pressure combination which uh is uh very + + align:start position:0% +pressure combination which uh is uh very + + + align:start position:0% +pressure combination which uh is uh very +nearly identical to the uh + + align:start position:0% +nearly identical to the uh + + + align:start position:0% +nearly identical to the uh +solidification temperature this is not + + align:start position:0% +solidification temperature this is not + + + align:start position:0% +solidification temperature this is not +to scale so this is slightly higher than + + align:start position:0% +to scale so this is slightly higher than + + + align:start position:0% +to scale so this is slightly higher than +Z degrees C it's about 1/ 100th of a + + align:start position:0% +Z degrees C it's about 1/ 100th of a + + + align:start position:0% +Z degrees C it's about 1/ 100th of a +degrees of a degree uh above zero at a + + align:start position:0% +degrees of a degree uh above zero at a + + + align:start position:0% +degrees of a degree uh above zero at a +reduced pressure of 4.58 millimeters of + + align:start position:0% +reduced pressure of 4.58 millimeters of + + + align:start position:0% +reduced pressure of 4.58 millimeters of +mercury and at this point here the + + align:start position:0% +mercury and at this point here the + + + align:start position:0% +mercury and at this point here the +triple point you in fact have ice cubes + + align:start position:0% +triple point you in fact have ice cubes + + + align:start position:0% +triple point you in fact have ice cubes +floating in boiling water there's the + + align:start position:0% +floating in boiling water there's the + + + align:start position:0% +floating in boiling water there's the +triple point and then the last thing was + + align:start position:0% +triple point and then the last thing was + + + align:start position:0% +triple point and then the last thing was +I I talked about super critical fluids + + align:start position:0% +I I talked about super critical fluids + + + align:start position:0% +I I talked about super critical fluids +at the end of last lecture uh just for + + align:start position:0% +at the end of last lecture uh just for + + + align:start position:0% +at the end of last lecture uh just for +completeness in the case of water water + + align:start position:0% +completeness in the case of water water + + + align:start position:0% +completeness in the case of water water +turns into a supercritical fluid at the + + align:start position:0% +turns into a supercritical fluid at the + + + align:start position:0% +turns into a supercritical fluid at the +elevated uh temperature of 374 de C 218 + + align:start position:0% +elevated uh temperature of 374 de C 218 + + + align:start position:0% +elevated uh temperature of 374 de C 218 +atmospheres above this pressure + + align:start position:0% +atmospheres above this pressure + + + align:start position:0% +atmospheres above this pressure +temperature pair we have something that + + align:start position:0% +temperature pair we have something that + + + align:start position:0% +temperature pair we have something that +is simply fluid it's neither a liquid + + align:start position:0% +is simply fluid it's neither a liquid + + + align:start position:0% +is simply fluid it's neither a liquid +nor a a vapor You could argue that it's + + align:start position:0% +nor a a vapor You could argue that it's + + + align:start position:0% +nor a a vapor You could argue that it's +a highly condensed vapor or highly + + align:start position:0% +a highly condensed vapor or highly + + + align:start position:0% +a highly condensed vapor or highly +rarified liquid but it uh it has a the + + align:start position:0% +rarified liquid but it uh it has a the + + + align:start position:0% +rarified liquid but it uh it has a the +properties of a of a super critical + + align:start position:0% +properties of a of a super critical + + + align:start position:0% +properties of a of a super critical +fluid so uh what I want to do today what + + align:start position:0% +fluid so uh what I want to do today what + + + align:start position:0% +fluid so uh what I want to do today what +I want to do today is to now uh look at + + align:start position:0% +I want to do today is to now uh look at + + + align:start position:0% +I want to do today is to now uh look at +um multicomponent systems and we want to + + align:start position:0% +um multicomponent systems and we want to + + + align:start position:0% +um multicomponent systems and we want to +start with a two component + + align:start position:0% + + + + align:start position:0% + +systems two component + + align:start position:0% + + + + align:start position:0% + +systems so we're not going to be talking + + align:start position:0% +systems so we're not going to be talking + + + align:start position:0% +systems so we're not going to be talking +about pure materials c will equal two so + + align:start position:0% +about pure materials c will equal two so + + + align:start position:0% +about pure materials c will equal two so +that means now we have to think about + + align:start position:0% +that means now we have to think about + + + align:start position:0% +that means now we have to think about +temperature pressure and composition + + align:start position:0% +temperature pressure and composition + + + align:start position:0% +temperature pressure and composition +because composition is a variable + + align:start position:0% +because composition is a variable + + + align:start position:0% +because composition is a variable +between the two components + + align:start position:0% +between the two components + + + align:start position:0% +between the two components +components and that gets to be messy + + align:start position:0% +components and that gets to be messy + + + align:start position:0% +components and that gets to be messy +because we already + + align:start position:0% +because we already + + + align:start position:0% +because we already +had uh pressure temperature diagram for + + align:start position:0% +had uh pressure temperature diagram for + + + align:start position:0% +had uh pressure temperature diagram for +let's say component a this is component + + align:start position:0% +let's say component a this is component + + + align:start position:0% +let's say component a this is component +a and over here I've got the pressure + + align:start position:0% +a and over here I've got the pressure + + + align:start position:0% +a and over here I've got the pressure +temperature variation of component B and + + align:start position:0% +temperature variation of component B and + + + align:start position:0% +temperature variation of component B and +here I've drawn the solid liquid + + align:start position:0% +here I've drawn the solid liquid + + + align:start position:0% +here I've drawn the solid liquid +coexistance curve as it normally is + + align:start position:0% +coexistance curve as it normally is + + + align:start position:0% +coexistance curve as it normally is +found in most materials which is to say + + align:start position:0% +found in most materials which is to say + + + align:start position:0% +found in most materials which is to say +positive because solids are generally + + align:start position:0% +positive because solids are generally + + + align:start position:0% +positive because solids are generally +denser than the uh than the liquids + + align:start position:0% +denser than the uh than the liquids + + + align:start position:0% +denser than the uh than the liquids +water is one of the exceptions so now + + align:start position:0% +water is one of the exceptions so now + + + align:start position:0% +water is one of the exceptions so now +the question is how do various + + align:start position:0% +the question is how do various + + + align:start position:0% +the question is how do various +properties change with composition so if + + align:start position:0% +properties change with composition so if + + + align:start position:0% +properties change with composition so if +I ask what's going on in between here so + + align:start position:0% +I ask what's going on in between here so + + + align:start position:0% +I ask what's going on in between here so +I can join these two so I I'm going to + + align:start position:0% +I can join these two so I I'm going to + + + align:start position:0% +I can join these two so I I'm going to +need a three-dimensional plot pressure + + align:start position:0% +need a three-dimensional plot pressure + + + align:start position:0% +need a three-dimensional plot pressure +temperature composition so I have an + + align:start position:0% +temperature composition so I have an + + + align:start position:0% +temperature composition so I have an +Infinity of uni phase diagrams all + + align:start position:0% +Infinity of uni phase diagrams all + + + align:start position:0% +Infinity of uni phase diagrams all +across here from Pure a all the way over + + align:start position:0% +across here from Pure a all the way over + + + align:start position:0% +across here from Pure a all the way over +to Pure B with all of the different + + align:start position:0% +to Pure B with all of the different + + + align:start position:0% +to Pure B with all of the different +composition ratios in between so for + + align:start position:0% +composition ratios in between so for + + + align:start position:0% +composition ratios in between so for +example I could look at here's the + + align:start position:0% +example I could look at here's the + + + align:start position:0% +example I could look at here's the +melting point this is the melting point + + align:start position:0% +melting point this is the melting point + + + align:start position:0% +melting point this is the melting point +of a and here's the melting point of B + + align:start position:0% +of a and here's the melting point of B + + + align:start position:0% +of a and here's the melting point of B +and I might ask how does the melting + + align:start position:0% +and I might ask how does the melting + + + align:start position:0% +and I might ask how does the melting +point vary with composition so is that a + + align:start position:0% +point vary with composition so is that a + + + align:start position:0% +point vary with composition so is that a +case of is it is a case of just connect + + align:start position:0% +case of is it is a case of just connect + + + align:start position:0% +case of is it is a case of just connect +the dots if I know the melting points of + + align:start position:0% +the dots if I know the melting points of + + + align:start position:0% +the dots if I know the melting points of +the two end members say copper and + + align:start position:0% +the two end members say copper and + + + align:start position:0% +the two end members say copper and +nickel and I want to know what's the + + align:start position:0% +nickel and I want to know what's the + + + align:start position:0% +nickel and I want to know what's the +melting point of a 50/50 copper nickel + + align:start position:0% +melting point of a 50/50 copper nickel + + + align:start position:0% +melting point of a 50/50 copper nickel +alloy is it just the halfway temperature + + align:start position:0% +alloy is it just the halfway temperature + + + align:start position:0% +alloy is it just the halfway temperature +between the two or does the temperature + + align:start position:0% +between the two or does the temperature + + + align:start position:0% +between the two or does the temperature +go through a local maximum or does it go + + align:start position:0% +go through a local maximum or does it go + + + align:start position:0% +go through a local maximum or does it go +through a local minimum or does the + + align:start position:0% +through a local minimum or does the + + + align:start position:0% +through a local minimum or does the +temperature go nuts I mean the question + + align:start position:0% +temperature go nuts I mean the question + + + align:start position:0% +temperature go nuts I mean the question +is how does temperature of some critical + + align:start position:0% +is how does temperature of some critical + + + align:start position:0% +is how does temperature of some critical +feature vary with composition so we need + + align:start position:0% +feature vary with composition so we need + + + align:start position:0% +feature vary with composition so we need +to look at three-dimensional stability + + align:start position:0% +to look at three-dimensional stability + + + align:start position:0% +to look at three-dimensional stability +maps and this is a pain in the neck + + align:start position:0% +maps and this is a pain in the neck + + + align:start position:0% +maps and this is a pain in the neck +because it's 3D and it's it's messy but + + align:start position:0% +because it's 3D and it's it's messy but + + + align:start position:0% +because it's 3D and it's it's messy but +fortunately this is + + align:start position:0% +fortunately this is + + + align:start position:0% +fortunately this is +3091 and 3091 is 3091 is concerned about + + align:start position:0% +3091 and 3091 is 3091 is concerned about + + + align:start position:0% +3091 and 3091 is 3091 is concerned about +sof Solid State chemistry so in 3091 we + + align:start position:0% +sof Solid State chemistry so in 3091 we + + + align:start position:0% +sof Solid State chemistry so in 3091 we +care more about liquid solid + + align:start position:0% + + + + align:start position:0% + +equilibrium instead of liquid Vapor + + align:start position:0% +equilibrium instead of liquid Vapor + + + align:start position:0% +equilibrium instead of liquid Vapor +equilibrium because we don't process too + + align:start position:0% +equilibrium because we don't process too + + + align:start position:0% +equilibrium because we don't process too +many uh materials in the vapor State we + + align:start position:0% +many uh materials in the vapor State we + + + align:start position:0% +many uh materials in the vapor State we +don't use too many materials as Vapors + + align:start position:0% +don't use too many materials as Vapors + + + align:start position:0% +don't use too many materials as Vapors +this is the equilibrium that's most + + align:start position:0% +this is the equilibrium that's most + + + align:start position:0% +this is the equilibrium that's most +important so when we we know that + + align:start position:0% +important so when we we know that + + + align:start position:0% +important so when we we know that +equilibria equilibria depend upon + + align:start position:0% +equilibria equilibria depend upon + + + align:start position:0% +equilibria equilibria depend upon +depend upon temperature pressure and + + align:start position:0% +depend upon temperature pressure and + + + align:start position:0% +depend upon temperature pressure and +composition and it turns out that when + + align:start position:0% +composition and it turns out that when + + + align:start position:0% +composition and it turns out that when +it comes to the liquid solid equilibrium + + align:start position:0% +it comes to the liquid solid equilibrium + + + align:start position:0% +it comes to the liquid solid equilibrium +liquid solid equilibrium is strongly + + align:start position:0% + + + + align:start position:0% + +dependent there's a strong dependence + + align:start position:0% +dependent there's a strong dependence + + + align:start position:0% +dependent there's a strong dependence +between the temperature of + + align:start position:0% +between the temperature of + + + align:start position:0% +between the temperature of +transformation and + + align:start position:0% +transformation and + + + align:start position:0% +transformation and +composition whereas the relationship + + align:start position:0% +composition whereas the relationship + + + align:start position:0% +composition whereas the relationship +between the temperature of the trans + + align:start position:0% +between the temperature of the trans + + + align:start position:0% +between the temperature of the trans +transformation and pressure is + + align:start position:0% +transformation and pressure is + + + align:start position:0% +transformation and pressure is +weakly weakly dependent there's a weak + + align:start position:0% +weakly weakly dependent there's a weak + + + align:start position:0% +weakly weakly dependent there's a weak +dependence between pressure and the + + align:start position:0% +dependence between pressure and the + + + align:start position:0% +dependence between pressure and the +temperature of the transformation and we + + align:start position:0% +temperature of the transformation and we + + + align:start position:0% +temperature of the transformation and we +saw that last day these are not to scale + + align:start position:0% +saw that last day these are not to scale + + + align:start position:0% +saw that last day these are not to scale +in other words these lines are nearly + + align:start position:0% +in other words these lines are nearly + + + align:start position:0% +in other words these lines are nearly +vertical for solid liquid you would have + + align:start position:0% +vertical for solid liquid you would have + + + align:start position:0% +vertical for solid liquid you would have +to apply geological pressures to alter + + align:start position:0% +to apply geological pressures to alter + + + align:start position:0% +to apply geological pressures to alter +the melting point of water substantially + + align:start position:0% +the melting point of water substantially + + + align:start position:0% +the melting point of water substantially +all right whereas we saw it doesn't take + + align:start position:0% +all right whereas we saw it doesn't take + + + align:start position:0% +all right whereas we saw it doesn't take +anything more than just a rise in + + align:start position:0% +anything more than just a rise in + + + align:start position:0% +anything more than just a rise in +elevation several thousand feet to move + + align:start position:0% +elevation several thousand feet to move + + + align:start position:0% +elevation several thousand feet to move +the boiling point a lot so that means + + align:start position:0% +the boiling point a lot so that means + + + align:start position:0% +the boiling point a lot so that means +that I can throw away the pressure + + align:start position:0% +that I can throw away the pressure + + + align:start position:0% +that I can throw away the pressure +dependence throw away the pressure + + align:start position:0% +dependence throw away the pressure + + + align:start position:0% +dependence throw away the pressure +dependence and just focus on the + + align:start position:0% +dependence and just focus on the + + + align:start position:0% +dependence and just focus on the +two-dimensional relationship between the + + align:start position:0% +two-dimensional relationship between the + + + align:start position:0% +two-dimensional relationship between the +temperature of a transformation and the + + align:start position:0% +temperature of a transformation and the + + + align:start position:0% +temperature of a transformation and the +composition so that's what we're going + + align:start position:0% +composition so that's what we're going + + + align:start position:0% +composition so that's what we're going +to do we're going to look at three + + align:start position:0% +to do we're going to look at three + + + align:start position:0% +to do we're going to look at three +different types of of binary systems and + + align:start position:0% +different types of of binary systems and + + + align:start position:0% +different types of of binary systems and +in each case we're going to assume that + + align:start position:0% +in each case we're going to assume that + + + align:start position:0% +in each case we're going to assume that +the pressure is one atmosphere and we + + align:start position:0% +the pressure is one atmosphere and we + + + align:start position:0% +the pressure is one atmosphere and we +know that the the dependence of the + + align:start position:0% +know that the the dependence of the + + + align:start position:0% +know that the the dependence of the +transer temperatures that we write is + + align:start position:0% +transer temperatures that we write is + + + align:start position:0% +transer temperatures that we write is +going to be negligible in terms of the + + align:start position:0% +going to be negligible in terms of the + + + align:start position:0% +going to be negligible in terms of the +impact that pressure might have on them + + align:start position:0% +impact that pressure might have on them + + + align:start position:0% +impact that pressure might have on them +so let's look at we're going to look at + + align:start position:0% +so let's look at we're going to look at + + + align:start position:0% +so let's look at we're going to look at +three different types of uh uh systems + + align:start position:0% +three different types of uh uh systems + + + align:start position:0% +three different types of uh uh systems +and they're all dependent upon the + + align:start position:0% +and they're all dependent upon the + + + align:start position:0% +and they're all dependent upon the +extent of solubility and I've given them + + align:start position:0% +extent of solubility and I've given them + + + align:start position:0% +extent of solubility and I've given them +the very um oh how what's the word very + + align:start position:0% +the very um oh how what's the word very + + + align:start position:0% +the very um oh how what's the word very +uh catchy very catchy uh distinctions of + + align:start position:0% +uh catchy very catchy uh distinctions of + + + align:start position:0% +uh catchy very catchy uh distinctions of +type one type two and type three all + + align:start position:0% +type one type two and type three all + + + align:start position:0% +type one type two and type three all +right so let's look at type one type one + + align:start position:0% +right so let's look at type one type one + + + align:start position:0% +right so let's look at type one type one +type binary system okay and type one + + align:start position:0% +type binary system okay and type one + + + align:start position:0% +type binary system okay and type one +binary system has + + align:start position:0% +binary system has + + + align:start position:0% +binary system has +complete complete + + align:start position:0% +complete complete + + + align:start position:0% +complete complete +solubility by this I mean complete + + align:start position:0% +solubility by this I mean complete + + + align:start position:0% +solubility by this I mean complete +solubility of the two components + + align:start position:0% +solubility of the two components + + + align:start position:0% +solubility of the two components +complete solubility in + + align:start position:0% +complete solubility in + + + align:start position:0% +complete solubility in +solid and liquid + + align:start position:0% +solid and liquid + + + align:start position:0% +solid and liquid +States so that is to say if I mix A and + + align:start position:0% +States so that is to say if I mix A and + + + align:start position:0% +States so that is to say if I mix A and +B they will mix in all proportions as + + align:start position:0% +B they will mix in all proportions as + + + align:start position:0% +B they will mix in all proportions as +solids and they'll mix in all + + align:start position:0% +solids and they'll mix in all + + + align:start position:0% +solids and they'll mix in all +proportions as liquids and the second + + align:start position:0% +proportions as liquids and the second + + + align:start position:0% +proportions as liquids and the second +thing is we're looking looking at change + + align:start position:0% +thing is we're looking looking at change + + + align:start position:0% +thing is we're looking looking at change +of + + align:start position:0% +of + + + align:start position:0% +of +state change of state so this diagram + + align:start position:0% +state change of state so this diagram + + + align:start position:0% +state change of state so this diagram +applies to a change of state and since + + align:start position:0% +applies to a change of state and since + + + align:start position:0% +applies to a change of state and since +we're talking + + align:start position:0% +we're talking + + + align:start position:0% +we're talking +about solid liquid that's the only one + + align:start position:0% +about solid liquid that's the only one + + + align:start position:0% +about solid liquid that's the only one +we need to uh document + + align:start position:0% +we need to uh document + + + align:start position:0% +we need to uh document +so and you know let's think about what's + + align:start position:0% +so and you know let's think about what's + + + align:start position:0% +so and you know let's think about what's +the relevant chemistry here I mean I've + + align:start position:0% +the relevant chemistry here I mean I've + + + align:start position:0% +the relevant chemistry here I mean I've +been telling you that phase diagrams are + + align:start position:0% +been telling you that phase diagrams are + + + align:start position:0% +been telling you that phase diagrams are +stability maps and you can just look at + + align:start position:0% +stability maps and you can just look at + + + align:start position:0% +stability maps and you can just look at +them and and consult them but there's + + align:start position:0% +them and and consult them but there's + + + align:start position:0% +them and and consult them but there's +always some basic chemistry embedded in + + align:start position:0% +always some basic chemistry embedded in + + + align:start position:0% +always some basic chemistry embedded in +these diagrams so for example if it were + + align:start position:0% +these diagrams so for example if it were + + + align:start position:0% +these diagrams so for example if it were +a metal system and I were to tell you + + align:start position:0% +a metal system and I were to tell you + + + align:start position:0% +a metal system and I were to tell you +that these two metals a and b mix in all + + align:start position:0% +that these two metals a and b mix in all + + + align:start position:0% +that these two metals a and b mix in all +proportions as solids and liquids what + + align:start position:0% +proportions as solids and liquids what + + + align:start position:0% +proportions as solids and liquids what +would have to be the characteristics of + + align:start position:0% +would have to be the characteristics of + + + align:start position:0% +would have to be the characteristics of +those two metals they would have to be + + align:start position:0% +those two metals they would have to be + + + align:start position:0% +those two metals they would have to be +either very nearly similar or maximally + + align:start position:0% +either very nearly similar or maximally + + + align:start position:0% +either very nearly similar or maximally +different they have to be very nearly + + align:start position:0% +different they have to be very nearly + + + align:start position:0% +different they have to be very nearly +similar and in fact that's it's the sort + + align:start position:0% +similar and in fact that's it's the sort + + + align:start position:0% +similar and in fact that's it's the sort +of a takeoff on like dissolves like so + + align:start position:0% +of a takeoff on like dissolves like so + + + align:start position:0% +of a takeoff on like dissolves like so +complete solid solubility in a liquid + + align:start position:0% +complete solid solubility in a liquid + + + align:start position:0% +complete solid solubility in a liquid +state with respect to metals when it + + align:start position:0% +state with respect to metals when it + + + align:start position:0% +state with respect to metals when it +comes to Metals there's a a set of rules + + align:start position:0% +comes to Metals there's a a set of rules + + + align:start position:0% +comes to Metals there's a a set of rules +called the Hume Ry + + align:start position:0% +called the Hume Ry + + + align:start position:0% +called the Hume Ry +rules Hume Ry was a a British uh + + align:start position:0% +rules Hume Ry was a a British uh + + + align:start position:0% +rules Hume Ry was a a British uh +metallurgist and he + + align:start position:0% +metallurgist and he + + + align:start position:0% +metallurgist and he +enunciated a set of rules for uh + + align:start position:0% +enunciated a set of rules for uh + + + align:start position:0% +enunciated a set of rules for uh +identifying candidate systems that will + + align:start position:0% +identifying candidate systems that will + + + align:start position:0% +identifying candidate systems that will +have this type of phase diagram and + + align:start position:0% +have this type of phase diagram and + + + align:start position:0% +have this type of phase diagram and +they're very simple anybody in 3091 + + align:start position:0% +they're very simple anybody in 3091 + + + align:start position:0% +they're very simple anybody in 3091 +would have come up with these rules if + + align:start position:0% +would have come up with these rules if + + + align:start position:0% +would have come up with these rules if +you thought about it before Hume R but + + align:start position:0% +you thought about it before Hume R but + + + align:start position:0% +you thought about it before Hume R but +he beat you to it so you can't get the + + align:start position:0% +he beat you to it so you can't get the + + + align:start position:0% +he beat you to it so you can't get the +glory anymore but let's think about it + + align:start position:0% +glory anymore but let's think about it + + + align:start position:0% +glory anymore but let's think about it +what would have to be the situation if + + align:start position:0% +what would have to be the situation if + + + align:start position:0% +what would have to be the situation if +the two metals A and B are going to mix + + align:start position:0% +the two metals A and B are going to mix + + + align:start position:0% +the two metals A and B are going to mix +in all proportions then they must be + + align:start position:0% +in all proportions then they must be + + + align:start position:0% +in all proportions then they must be +very similar so they must have similar + + align:start position:0% +very similar so they must have similar + + + align:start position:0% +very similar so they must have similar +Crystal + + align:start position:0% +Crystal + + + align:start position:0% +Crystal +structures Crystal structures that way + + align:start position:0% +structures Crystal structures that way + + + align:start position:0% +structures Crystal structures that way +you get simple substitutional solid + + align:start position:0% +you get simple substitutional solid + + + align:start position:0% +you get simple substitutional solid +Solutions and furthermore if they're + + align:start position:0% +Solutions and furthermore if they're + + + align:start position:0% +Solutions and furthermore if they're +going to substitute solid for solid they + + align:start position:0% +going to substitute solid for solid they + + + align:start position:0% +going to substitute solid for solid they +should have similar Atomic Dimensions + + align:start position:0% +should have similar Atomic Dimensions + + + align:start position:0% +should have similar Atomic Dimensions +right it does no good to have two FCC + + align:start position:0% +right it does no good to have two FCC + + + align:start position:0% +right it does no good to have two FCC +Metals mixing where one has + + align:start position:0% +Metals mixing where one has + + + align:start position:0% +Metals mixing where one has +a atomic radius that is so large that it + + align:start position:0% +a atomic radius that is so large that it + + + align:start position:0% +a atomic radius that is so large that it +has to force fit into the lattice of the + + align:start position:0% +has to force fit into the lattice of the + + + align:start position:0% +has to force fit into the lattice of the +other similar Atomic + + align:start position:0% + + + + align:start position:0% + +volumes similar Atomic volumes and + + align:start position:0% +volumes similar Atomic volumes and + + + align:start position:0% +volumes similar Atomic volumes and +lastly bring in some chemistry we want + + align:start position:0% +lastly bring in some chemistry we want + + + align:start position:0% +lastly bring in some chemistry we want +them to mix and not chemically react so + + align:start position:0% +them to mix and not chemically react so + + + align:start position:0% +them to mix and not chemically react so +they should have a + + align:start position:0% +they should have a + + + align:start position:0% +they should have a +small value in electro negativity + + align:start position:0% +small value in electro negativity + + + align:start position:0% +small value in electro negativity +difference if they're both the same size + + align:start position:0% +difference if they're both the same size + + + align:start position:0% +difference if they're both the same size +the both crystal structure but they have + + align:start position:0% +the both crystal structure but they have + + + align:start position:0% +the both crystal structure but they have +a high El negativity difference they're + + align:start position:0% +a high El negativity difference they're + + + align:start position:0% +a high El negativity difference they're +going to engage an electron transfer so + + align:start position:0% +going to engage an electron transfer so + + + align:start position:0% +going to engage an electron transfer so +that's no good but I I think this set of + + align:start position:0% +that's no good but I I think this set of + + + align:start position:0% +that's no good but I I think this set of +hum Ry rules is nice to reflect upon in + + align:start position:0% +hum Ry rules is nice to reflect upon in + + + align:start position:0% +hum Ry rules is nice to reflect upon in +the light of everything else we've + + align:start position:0% +the light of everything else we've + + + align:start position:0% +the light of everything else we've +learned 3091 because the phase diagrams + + align:start position:0% +learned 3091 because the phase diagrams + + + align:start position:0% +learned 3091 because the phase diagrams +have as I said earlier they have + + align:start position:0% +have as I said earlier they have + + + align:start position:0% +have as I said earlier they have +embedded in them a lot of basic + + align:start position:0% +embedded in them a lot of basic + + + align:start position:0% +embedded in them a lot of basic +chemistry which goes back to electronic + + align:start position:0% +chemistry which goes back to electronic + + + align:start position:0% +chemistry which goes back to electronic +structure of the constituents so let's + + align:start position:0% +structure of the constituents so let's + + + align:start position:0% +structure of the constituents so let's +draw a schematic of an AB diagram + + align:start position:0% +draw a schematic of an AB diagram + + + align:start position:0% +draw a schematic of an AB diagram +for one such system that I call type one + + align:start position:0% +for one such system that I call type one + + + align:start position:0% +for one such system that I call type one +so I'm plotting a versus B this is + + align:start position:0% +so I'm plotting a versus B this is + + + align:start position:0% +so I'm plotting a versus B this is +temperature on the vertical axis + + align:start position:0% +temperature on the vertical axis + + + align:start position:0% +temperature on the vertical axis +horizontal axis is composition so on the + + align:start position:0% +horizontal axis is composition so on the + + + align:start position:0% +horizontal axis is composition so on the +left side I have pure a the right side I + + align:start position:0% +left side I have pure a the right side I + + + align:start position:0% +left side I have pure a the right side I +have pure B and I'm looking at solid + + align:start position:0% +have pure B and I'm looking at solid + + + align:start position:0% +have pure B and I'm looking at solid +liquid equilibrium so at this extreme + + align:start position:0% +liquid equilibrium so at this extreme + + + align:start position:0% +liquid equilibrium so at this extreme +pure a this n member must be the melting + + align:start position:0% +pure a this n member must be the melting + + + align:start position:0% +pure a this n member must be the melting +point of pure + + align:start position:0% +point of pure + + + align:start position:0% +point of pure +a and the Other Extreme is pure B so + + align:start position:0% +a and the Other Extreme is pure B so + + + align:start position:0% +a and the Other Extreme is pure B so +this is the melting point of pure B and + + align:start position:0% +this is the melting point of pure B and + + + align:start position:0% +this is the melting point of pure B and +I've drawn it just arbitrarily where the + + align:start position:0% +I've drawn it just arbitrarily where the + + + align:start position:0% +I've drawn it just arbitrarily where the +melting point of B has happens to be + + align:start position:0% +melting point of B has happens to be + + + align:start position:0% +melting point of B has happens to be +higher than the melting point of a but + + align:start position:0% +higher than the melting point of a but + + + align:start position:0% +higher than the melting point of a but +it doesn't matter one has to be larger + + align:start position:0% +it doesn't matter one has to be larger + + + align:start position:0% +it doesn't matter one has to be larger +than the other and so now this is what + + align:start position:0% +than the other and so now this is what + + + align:start position:0% +than the other and so now this is what +the phase di this is going to answer the + + align:start position:0% +the phase di this is going to answer the + + + align:start position:0% +the phase di this is going to answer the +question how does melting point vary as + + align:start position:0% +question how does melting point vary as + + + align:start position:0% +question how does melting point vary as +a function of composition it varies like + + align:start position:0% +a function of composition it varies like + + + align:start position:0% +a function of composition it varies like +this it's not a straight line for two + + align:start position:0% +this it's not a straight line for two + + + align:start position:0% +this it's not a straight line for two +reasons the first one being that if when + + align:start position:0% +reasons the first one being that if when + + + align:start position:0% +reasons the first one being that if when +you take thermodynamics uh subsequently + + align:start position:0% +you take thermodynamics uh subsequently + + + align:start position:0% +you take thermodynamics uh subsequently +if you choose to do so you'll understand + + align:start position:0% +if you choose to do so you'll understand + + + align:start position:0% +if you choose to do so you'll understand +the the physical chemistry behind what + + align:start position:0% +the the physical chemistry behind what + + + align:start position:0% +the the physical chemistry behind what +I'm going to tell you let me just state + + align:start position:0% +I'm going to tell you let me just state + + + align:start position:0% +I'm going to tell you let me just state +it without proof that if C is greater + + align:start position:0% +it without proof that if C is greater + + + align:start position:0% +it without proof that if C is greater +than one in other words if you're not in + + align:start position:0% +than one in other words if you're not in + + + align:start position:0% +than one in other words if you're not in +a pure material if you're in a + + align:start position:0% +a pure material if you're in a + + + align:start position:0% +a pure material if you're in a +multicomponent system if C is greater + + align:start position:0% +multicomponent system if C is greater + + + align:start position:0% +multicomponent system if C is greater +than one it's impossible to go from + + align:start position:0% +than one it's impossible to go from + + + align:start position:0% +than one it's impossible to go from +phase + + align:start position:0% +phase + + + align:start position:0% +phase +one to phase + + align:start position:0% +one to phase + + + align:start position:0% +one to phase +two cannot go from phase one to phase + + align:start position:0% +two cannot go from phase one to phase + + + align:start position:0% +two cannot go from phase one to phase +two without a + + align:start position:0% +two without a + + + align:start position:0% +two without a +two-phase region in + + align:start position:0% +two-phase region in + + + align:start position:0% +two-phase region in +between so we can't go from all liquid + + align:start position:0% +between so we can't go from all liquid + + + align:start position:0% +between so we can't go from all liquid +to all solid remember we said these mix + + align:start position:0% +to all solid remember we said these mix + + + align:start position:0% +to all solid remember we said these mix +in all proportions down here so solids + + align:start position:0% +in all proportions down here so solids + + + align:start position:0% +in all proportions down here so solids +you can mix any mix any ratio of a and b + + align:start position:0% +you can mix any mix any ratio of a and b + + + align:start position:0% +you can mix any mix any ratio of a and b +as solids any mix of a and b as liquids + + align:start position:0% +as solids any mix of a and b as liquids + + + align:start position:0% +as solids any mix of a and b as liquids +but because we must go through a + + align:start position:0% +but because we must go through a + + + align:start position:0% +but because we must go through a +two-phase regime this opens + + align:start position:0% +two-phase regime this opens + + + align:start position:0% +two-phase regime this opens +up to give a two-phase regime so up here + + align:start position:0% +up to give a two-phase regime so up here + + + align:start position:0% +up to give a two-phase regime so up here +this is all liquid down here this is all + + align:start position:0% +this is all liquid down here this is all + + + align:start position:0% +this is all liquid down here this is all +solid and in between is a two-phase + + align:start position:0% +solid and in between is a two-phase + + + align:start position:0% +solid and in between is a two-phase +regime of liquid and solid we can call + + align:start position:0% +regime of liquid and solid we can call + + + align:start position:0% +regime of liquid and solid we can call +it + + align:start position:0% +it + + + align:start position:0% +it +slush slush we've seen slush before + + align:start position:0% +slush slush we've seen slush before + + + align:start position:0% +slush slush we've seen slush before +we've seen ice slush in water the + + align:start position:0% +we've seen ice slush in water the + + + align:start position:0% +we've seen ice slush in water the +two-phase equilibrium for a pure + + align:start position:0% +two-phase equilibrium for a pure + + + align:start position:0% +two-phase equilibrium for a pure +material this is now Liquid Plus solid + + align:start position:0% +material this is now Liquid Plus solid + + + align:start position:0% +material this is now Liquid Plus solid +in a uh multicomponent system so up here + + align:start position:0% +in a uh multicomponent system so up here + + + align:start position:0% +in a uh multicomponent system so up here +we have singlephase + + align:start position:0% +we have singlephase + + + align:start position:0% +we have singlephase +liquid because they're mixing in all + + align:start position:0% +liquid because they're mixing in all + + + align:start position:0% +liquid because they're mixing in all +proportions so this is a solution down + + align:start position:0% +proportions so this is a solution down + + + align:start position:0% +proportions so this is a solution down +here these are solid Solutions and in + + align:start position:0% +here these are solid Solutions and in + + + align:start position:0% +here these are solid Solutions and in +here we + + align:start position:0% +here we + + + align:start position:0% +here we +have a two-phase regime a liquid phase + + align:start position:0% +have a two-phase regime a liquid phase + + + align:start position:0% +have a two-phase regime a liquid phase +homogeneous a solid phase + + align:start position:0% +homogeneous a solid phase + + + align:start position:0% +homogeneous a solid phase +homogeneous and this these lines are now + + align:start position:0% +homogeneous and this these lines are now + + + align:start position:0% +homogeneous and this these lines are now +no longer called the melting line or the + + align:start position:0% +no longer called the melting line or the + + + align:start position:0% +no longer called the melting line or the +or the freezing line we have two + + align:start position:0% +or the freezing line we have two + + + align:start position:0% +or the freezing line we have two +different lines right the upper line + + align:start position:0% +different lines right the upper line + + + align:start position:0% +different lines right the upper line +defines the lowest temperature for any + + align:start position:0% +defines the lowest temperature for any + + + align:start position:0% +defines the lowest temperature for any +composition pick any composition you + + align:start position:0% +composition pick any composition you + + + align:start position:0% +composition pick any composition you +want this temperature is the lowest + + align:start position:0% +want this temperature is the lowest + + + align:start position:0% +want this temperature is the lowest +composition at which you have only + + align:start position:0% +composition at which you have only + + + align:start position:0% +composition at which you have only +liquid present change the composition + + align:start position:0% +liquid present change the composition + + + align:start position:0% +liquid present change the composition +and that temperature changes but below + + align:start position:0% +and that temperature changes but below + + + align:start position:0% +and that temperature changes but below +this temperature you start to see the + + align:start position:0% +this temperature you start to see the + + + align:start position:0% +this temperature you start to see the +emergence of solid so this line here is + + align:start position:0% +emergence of solid so this line here is + + + align:start position:0% +emergence of solid so this line here is +called the liquidous + + align:start position:0% + + + + align:start position:0% + +liquidous liquidous + + align:start position:0% + + + + align:start position:0% + +is is the line associated with this + + align:start position:0% +is is the line associated with this + + + align:start position:0% +is is the line associated with this +reaction singlephase liquid goes to + + align:start position:0% +reaction singlephase liquid goes to + + + align:start position:0% +reaction singlephase liquid goes to +Liquid Plus + + align:start position:0% +Liquid Plus + + + align:start position:0% +Liquid Plus +solid and the lower line is called + + align:start position:0% +solid and the lower line is called + + + align:start position:0% +solid and the lower line is called +solidus the lower line is called solidus + + align:start position:0% +solidus the lower line is called solidus + + + align:start position:0% +solidus the lower line is called solidus +and it represents the complimentary set + + align:start position:0% +and it represents the complimentary set + + + align:start position:0% +and it represents the complimentary set +the solidus is the highest temperature + + align:start position:0% +the solidus is the highest temperature + + + align:start position:0% +the solidus is the highest temperature +at any composition for which you have + + align:start position:0% +at any composition for which you have + + + align:start position:0% +at any composition for which you have +only solid present if you see at the + + align:start position:0% +only solid present if you see at the + + + align:start position:0% +only solid present if you see at the +line that I've + + align:start position:0% +line that I've + + + align:start position:0% +line that I've +drawn the solidest temperature is the + + align:start position:0% +drawn the solidest temperature is the + + + align:start position:0% +drawn the solidest temperature is the +highest temperature for which we have + + align:start position:0% +highest temperature for which we have + + + align:start position:0% +highest temperature for which we have +solid solution present if we raise the + + align:start position:0% +solid solution present if we raise the + + + align:start position:0% +solid solution present if we raise the +temperature anymore we go into a + + align:start position:0% +temperature anymore we go into a + + + align:start position:0% +temperature anymore we go into a +two-phase regime some liquid starts to + + align:start position:0% +two-phase regime some liquid starts to + + + align:start position:0% +two-phase regime some liquid starts to +emerge so the solidus represents the + + align:start position:0% +emerge so the solidus represents the + + + align:start position:0% +emerge so the solidus represents the +highest temperature for all solid and + + align:start position:0% +highest temperature for all solid and + + + align:start position:0% +highest temperature for all solid and +and it represents solid goes to Liquid + + align:start position:0% +and it represents solid goes to Liquid + + + align:start position:0% +and it represents solid goes to Liquid +Plus solid homogeneous solid all right + + align:start position:0% +Plus solid homogeneous solid all right + + + align:start position:0% +Plus solid homogeneous solid all right +so let's write it again this is the + + align:start position:0% +so let's write it again this is the + + + align:start position:0% +so let's write it again this is the +lowest temperature + + align:start position:0% +lowest temperature + + + align:start position:0% +lowest temperature +for only + + align:start position:0% +for only + + + align:start position:0% +for only +liquid and this is at any c at any + + align:start position:0% +liquid and this is at any c at any + + + align:start position:0% +liquid and this is at any c at any +composition any value of composition and + + align:start position:0% +composition any value of composition and + + + align:start position:0% +composition any value of composition and +the solidest is the highest is the + + align:start position:0% +the solidest is the highest is the + + + align:start position:0% +the solidest is the highest is the +highest temperature for only solid to be + + align:start position:0% +highest temperature for only solid to be + + + align:start position:0% +highest temperature for only solid to be +present at any + + align:start position:0% + + + + align:start position:0% + +composition this only applies once you + + align:start position:0% +composition this only applies once you + + + align:start position:0% +composition this only applies once you +move off of Purity so in here this is + + align:start position:0% +move off of Purity so in here this is + + + align:start position:0% +move off of Purity so in here this is +showing you how things vary as a + + align:start position:0% +showing you how things vary as a + + + align:start position:0% +showing you how things vary as a +function of composition um and such a + + align:start position:0% +function of composition um and such a + + + align:start position:0% +function of composition um and such a +diagram that has such similarities + + align:start position:0% +diagram that has such similarities + + + align:start position:0% +diagram that has such similarities +because the N members must have common + + align:start position:0% +because the N members must have common + + + align:start position:0% +because the N members must have common +bonding common size and so on this type + + align:start position:0% +bonding common size and so on this type + + + align:start position:0% +bonding common size and so on this type +of a diagram is called + + align:start position:0% +of a diagram is called + + + align:start position:0% +of a diagram is called +isomorphous this is an isomorphous + + align:start position:0% +isomorphous this is an isomorphous + + + align:start position:0% +isomorphous this is an isomorphous +diagram and the shape looks like a lens + + align:start position:0% +diagram and the shape looks like a lens + + + align:start position:0% +diagram and the shape looks like a lens +doesn't it it looks like a lens it's a + + align:start position:0% +doesn't it it looks like a lens it's a + + + align:start position:0% +doesn't it it looks like a lens it's a +lens shaped diagram lens + + align:start position:0% + + + + align:start position:0% + +shaped lens shape but if you want to get + + align:start position:0% +shaped lens shape but if you want to get + + + align:start position:0% +shaped lens shape but if you want to get +fancy we don't say lens shape we say + + align:start position:0% +fancy we don't say lens shape we say + + + align:start position:0% +fancy we don't say lens shape we say +lenticular from the Latin lens Len the + + align:start position:0% +lenticular from the Latin lens Len the + + + align:start position:0% +lenticular from the Latin lens Len the +genitive is lenus so lenticular it's a + + align:start position:0% +genitive is lenus so lenticular it's a + + + align:start position:0% +genitive is lenus so lenticular it's a +lenticular diagram okay + + align:start position:0% +lenticular diagram okay + + + align:start position:0% +lenticular diagram okay +so now we have it let's look at some + + align:start position:0% +so now we have it let's look at some + + + align:start position:0% +so now we have it let's look at some +example systems let's look at some + + align:start position:0% +example systems let's look at some + + + align:start position:0% +example systems let's look at some +example systems that exhibit this kind + + align:start position:0% +example systems that exhibit this kind + + + align:start position:0% +example systems that exhibit this kind +of Behavior Uh Oh you know what before + + align:start position:0% +of Behavior Uh Oh you know what before + + + align:start position:0% +of Behavior Uh Oh you know what before +we do that I I meant to show you this we + + align:start position:0% +we do that I I meant to show you this we + + + align:start position:0% +we do that I I meant to show you this we +talked about what happens at ultra high + + align:start position:0% +talked about what happens at ultra high + + + align:start position:0% +talked about what happens at ultra high +pressures this is water we're down in + + align:start position:0% +pressures this is water we're down in + + + align:start position:0% +pressures this is water we're down in +here see look at this is now kilobars + + align:start position:0% +here see look at this is now kilobars + + + align:start position:0% +here see look at this is now kilobars +thousands of atmospheres so this is the + + align:start position:0% +thousands of atmospheres so this is the + + + align:start position:0% +thousands of atmospheres so this is the +normal line that you see that's this + + align:start position:0% +normal line that you see that's this + + + align:start position:0% +normal line that you see that's this +line that I've shown you that's here + + align:start position:0% +line that I've shown you that's here + + + align:start position:0% +line that I've shown you that's here +okay so there's ice at a density about + + align:start position:0% +okay so there's ice at a density about + + + align:start position:0% +okay so there's ice at a density about +0.92 and normal water is about one so + + align:start position:0% +0.92 and normal water is about one so + + + align:start position:0% +0.92 and normal water is about one so +ice floats on water but if you keep + + align:start position:0% +ice floats on water but if you keep + + + align:start position:0% +ice floats on water but if you keep +pressing eventually you'll force that + + align:start position:0% +pressing eventually you'll force that + + + align:start position:0% +pressing eventually you'll force that +crystal structure to change and it'll + + align:start position:0% +crystal structure to change and it'll + + + align:start position:0% +crystal structure to change and it'll +become more close packed and now you see + + align:start position:0% +become more close packed and now you see + + + align:start position:0% +become more close packed and now you see +normal behavior so liquid goes to solid + + align:start position:0% +normal behavior so liquid goes to solid + + + align:start position:0% +normal behavior so liquid goes to solid +and all of these different Roman + + align:start position:0% +and all of these different Roman + + + align:start position:0% +and all of these different Roman +numerals represent different Crystal + + align:start position:0% +numerals represent different Crystal + + + align:start position:0% +numerals represent different Crystal +structures ice has at least nine + + align:start position:0% +structures ice has at least nine + + + align:start position:0% +structures ice has at least nine +different Crystal structures okay and + + align:start position:0% +different Crystal structures okay and + + + align:start position:0% +different Crystal structures okay and +some of these are really interesting + + align:start position:0% +some of these are really interesting + + + align:start position:0% +some of these are really interesting +look at this one this is these are all + + align:start position:0% +look at this one this is these are all + + + align:start position:0% +look at this one this is these are all +triple points right this is ice 3 ice + + align:start position:0% +triple points right this is ice 3 ice + + + align:start position:0% +triple points right this is ice 3 ice +one and liquid so in a in a single + + align:start position:0% +one and liquid so in a in a single + + + align:start position:0% +one and liquid so in a in a single +component system that's a triple point + + align:start position:0% +component system that's a triple point + + + align:start position:0% +component system that's a triple point +that's uniquely defined now look at what + + align:start position:0% +that's uniquely defined now look at what + + + align:start position:0% +that's uniquely defined now look at what +happens over here this is a triple point + + align:start position:0% +happens over here this is a triple point + + + align:start position:0% +happens over here this is a triple point +between ice 6 ice7 and liquid and it's + + align:start position:0% +between ice 6 ice7 and liquid and it's + + + align:start position:0% +between ice 6 ice7 and liquid and it's +at about 80° C way up there now look at + + align:start position:0% +at about 80° C way up there now look at + + + align:start position:0% +at about 80° C way up there now look at +this one this is i7 I'm right I'm in a + + align:start position:0% +this one this is i7 I'm right I'm in a + + + align:start position:0% +this one this is i7 I'm right I'm in a +singlephase regime ice 7 it's 100° C I + + align:start position:0% +singlephase regime ice 7 it's 100° C I + + + align:start position:0% +singlephase regime ice 7 it's 100° C I +have to go to 25 kilobar but you know we + + align:start position:0% +have to go to 25 kilobar but you know we + + + align:start position:0% +have to go to 25 kilobar but you know we +have Laboratories so it's 100° C and it + + align:start position:0% +have Laboratories so it's 100° C and it + + + align:start position:0% +have Laboratories so it's 100° C and it +it's not Vapor remember water boils + + align:start position:0% +it's not Vapor remember water boils + + + align:start position:0% +it's not Vapor remember water boils +normal boiling point is 100 degrees C + + align:start position:0% +normal boiling point is 100 degrees C + + + align:start position:0% +normal boiling point is 100 degrees C +but if I apply 25 kilobars I not only + + align:start position:0% +but if I apply 25 kilobars I not only + + + align:start position:0% +but if I apply 25 kilobars I not only +move through the liquid I go not only + + align:start position:0% +move through the liquid I go not only + + + align:start position:0% +move through the liquid I go not only +through liquid I go right across the + + align:start position:0% +through liquid I go right across the + + + align:start position:0% +through liquid I go right across the +solid so you saw I brought the dry ice + + align:start position:0% +solid so you saw I brought the dry ice + + + align:start position:0% +solid so you saw I brought the dry ice +into the classroom by the way I was here + + align:start position:0% +into the classroom by the way I was here + + + align:start position:0% +into the classroom by the way I was here +yesterday there was still half of the + + align:start position:0% +yesterday there was still half of the + + + align:start position:0% +yesterday there was still half of the +block was still sitting there cuz I left + + align:start position:0% +block was still sitting there cuz I left + + + align:start position:0% +block was still sitting there cuz I left +it in the box and it was was had this + + align:start position:0% +it in the box and it was was had this + + + align:start position:0% +it in the box and it was was had this +little comfort zone of CO2 Vapor around + + align:start position:0% +little comfort zone of CO2 Vapor around + + + align:start position:0% +little comfort zone of CO2 Vapor around +it was just naturally thinning in took a + + align:start position:0% +it was just naturally thinning in took a + + + align:start position:0% +it was just naturally thinning in took a +long time what's my point my point is + + align:start position:0% +long time what's my point my point is + + + align:start position:0% +long time what's my point my point is +when you make such a metastable state + + align:start position:0% +when you make such a metastable state + + + align:start position:0% +when you make such a metastable state +and bring it into some unnatural + + align:start position:0% +and bring it into some unnatural + + + align:start position:0% +and bring it into some unnatural +conditions it will it will last for a + + align:start position:0% +conditions it will it will last for a + + + align:start position:0% +conditions it will it will last for a +long long time the kinetics are quite + + align:start position:0% +long long time the kinetics are quite + + + align:start position:0% +long long time the kinetics are quite +slow so let's say we go into the lab we + + align:start position:0% +slow so let's say we go into the lab we + + + align:start position:0% +slow so let's say we go into the lab we +make ice 7 it's 100° C it's 25 KOB and + + align:start position:0% +make ice 7 it's 100° C it's 25 KOB and + + + align:start position:0% +make ice 7 it's 100° C it's 25 KOB and +there's a party going on down the hall + + align:start position:0% +there's a party going on down the hall + + + align:start position:0% +there's a party going on down the hall +so we come out and we've got some ice + + align:start position:0% +so we come out and we've got some ice + + + align:start position:0% +so we come out and we've got some ice +seven and it's going it's going to start + + align:start position:0% +seven and it's going it's going to start + + + align:start position:0% +seven and it's going it's going to start +to want to to to melt right cuz the + + align:start position:0% +to want to to to melt right cuz the + + + align:start position:0% +to want to to to melt right cuz the +temperature's falling and the + + align:start position:0% +temperature's falling and the + + + align:start position:0% +temperature's falling and the +temperature is going to fall so you're + + align:start position:0% +temperature is going to fall so you're + + + align:start position:0% +temperature is going to fall so you're +going to move this way and down but some + + align:start position:0% +going to move this way and down but some + + + align:start position:0% +going to move this way and down but some +of it's going to be left so now you go + + align:start position:0% +of it's going to be left so now you go + + + align:start position:0% +of it's going to be left so now you go +up to somebody you take some ice seven + + align:start position:0% +up to somebody you take some ice seven + + + align:start position:0% +up to somebody you take some ice seven +you drop it in the drink and the drink + + align:start position:0% +you drop it in the drink and the drink + + + align:start position:0% +you drop it in the drink and the drink +heats up and starts to boil and the ice + + align:start position:0% +heats up and starts to boil and the ice + + + align:start position:0% +heats up and starts to boil and the ice +sinks to the bottom of the + + align:start position:0% + + + + align:start position:0% + +glass that might get someone to rethink + + align:start position:0% +glass that might get someone to rethink + + + align:start position:0% +glass that might get someone to rethink +their drinking habits you see but this + + align:start position:0% +their drinking habits you see but this + + + align:start position:0% +their drinking habits you see but this +is this is the power of changing + + align:start position:0% +is this is the power of changing + + + align:start position:0% +is this is the power of changing +pressure and temperature all right by + + align:start position:0% +pressure and temperature all right by + + + align:start position:0% +pressure and temperature all right by +the way those of you who know Cat's + + align:start position:0% +the way those of you who know Cat's + + + align:start position:0% +the way those of you who know Cat's +Cradle by Kurt Vaga there's ice nine it + + align:start position:0% +Cradle by Kurt Vaga there's ice nine it + + + align:start position:0% +Cradle by Kurt Vaga there's ice nine it +exists all right it's been characterized + + align:start position:0% +exists all right it's been characterized + + + align:start position:0% +exists all right it's been characterized +so somebody actually measured this stuff + + align:start position:0% +so somebody actually measured this stuff + + + align:start position:0% +so somebody actually measured this stuff +and we're still here we didn't freeze + + align:start position:0% +and we're still here we didn't freeze + + + align:start position:0% +and we're still here we didn't freeze +the whole world so you can relax he he + + align:start position:0% +the whole world so you can relax he he + + + align:start position:0% +the whole world so you can relax he he +needs to rename that maybe ice 11 or + + align:start position:0% +needs to rename that maybe ice 11 or + + + align:start position:0% +needs to rename that maybe ice 11 or +something I don't know if there are any + + align:start position:0% +something I don't know if there are any + + + align:start position:0% +something I don't know if there are any +more phases here okay so here's a here's + + align:start position:0% +more phases here okay so here's a here's + + + align:start position:0% +more phases here okay so here's a here's +a phase diagram copper nickel that's a + + align:start position:0% +a phase diagram copper nickel that's a + + + align:start position:0% +a phase diagram copper nickel that's a +lenticular diagram copper and nickel + + align:start position:0% +lenticular diagram copper and nickel + + + align:start position:0% +lenticular diagram copper and nickel +both FCC metals very similar in atomic + + align:start position:0% +both FCC metals very similar in atomic + + + align:start position:0% +both FCC metals very similar in atomic +Dimension very small electro negativity + + align:start position:0% +Dimension very small electro negativity + + + align:start position:0% +Dimension very small electro negativity +difference so you have a lens-shaped + + align:start position:0% +difference so you have a lens-shaped + + + align:start position:0% +difference so you have a lens-shaped +diagram copper melts at 1085 Centigrade + + align:start position:0% +diagram copper melts at 1085 Centigrade + + + align:start position:0% +diagram copper melts at 1085 Centigrade +nickel melts at 1455 and there's the + + align:start position:0% +nickel melts at 1455 and there's the + + + align:start position:0% +nickel melts at 1455 and there's the +liquidous and the solidest and in + + align:start position:0% +liquidous and the solidest and in + + + align:start position:0% +liquidous and the solidest and in +between if you cool at any one of these + + align:start position:0% +between if you cool at any one of these + + + align:start position:0% +between if you cool at any one of these +uh concentrations you're going to go + + align:start position:0% +uh concentrations you're going to go + + + align:start position:0% +uh concentrations you're going to go +through this two-phase regime we're + + align:start position:0% +through this two-phase regime we're + + + align:start position:0% +through this two-phase regime we're +going to talk a little bit more about + + align:start position:0% +going to talk a little bit more about + + + align:start position:0% +going to talk a little bit more about +that in a second here's a ceramic system + + align:start position:0% +that in a second here's a ceramic system + + + align:start position:0% +that in a second here's a ceramic system +here's nickel ox oide magnesium oxide so + + align:start position:0% +here's nickel ox oide magnesium oxide so + + + align:start position:0% +here's nickel ox oide magnesium oxide so +this is an ionic solid right it's nickel + + align:start position:0% +this is an ionic solid right it's nickel + + + align:start position:0% +this is an ionic solid right it's nickel +cats magnesium cations I and oxide + + align:start position:0% +cats magnesium cations I and oxide + + + align:start position:0% +cats magnesium cations I and oxide +anions and the nickel and magnesium are + + align:start position:0% +anions and the nickel and magnesium are + + + align:start position:0% +anions and the nickel and magnesium are +roughly similar in size modest electro + + align:start position:0% +roughly similar in size modest electro + + + align:start position:0% +roughly similar in size modest electro +negativity difference and so this one + + align:start position:0% +negativity difference and so this one + + + align:start position:0% +negativity difference and so this one +starts at 20 uh 2,000 Centigrade goes up + + align:start position:0% +starts at 20 uh 2,000 Centigrade goes up + + + align:start position:0% +starts at 20 uh 2,000 Centigrade goes up +to 2800 Centigrade has a lens-shaped + + align:start position:0% +to 2800 Centigrade has a lens-shaped + + + align:start position:0% +to 2800 Centigrade has a lens-shaped +diagram here's one this is gold nickel + + align:start position:0% +diagram here's one this is gold nickel + + + align:start position:0% +diagram here's one this is gold nickel +it's almost lenticular look at the top + + align:start position:0% +it's almost lenticular look at the top + + + align:start position:0% +it's almost lenticular look at the top +part here there's the nickel melting + + align:start position:0% +part here there's the nickel melting + + + align:start position:0% +part here there's the nickel melting +point is up around + + align:start position:0% +point is up around + + + align:start position:0% +point is up around +1450 uh gold melts at 1063 it's almost + + align:start position:0% +1450 uh gold melts at 1063 it's almost + + + align:start position:0% +1450 uh gold melts at 1063 it's almost +perfectly lenticular with this little + + align:start position:0% +perfectly lenticular with this little + + + align:start position:0% +perfectly lenticular with this little +bit of a dip here sort of the liquid + + align:start position:0% +bit of a dip here sort of the liquid + + + align:start position:0% +bit of a dip here sort of the liquid +solid uh um analogy to an asot Trope but + + align:start position:0% +solid uh um analogy to an asot Trope but + + + align:start position:0% +solid uh um analogy to an asot Trope but +again you see they're both FCC Metals + + align:start position:0% +again you see they're both FCC Metals + + + align:start position:0% +again you see they're both FCC Metals +both FCC Metals but in this case the + + align:start position:0% +both FCC Metals but in this case the + + + align:start position:0% +both FCC Metals but in this case the +electr negativity difference is a little + + align:start position:0% +electr negativity difference is a little + + + align:start position:0% +electr negativity difference is a little +bit larger than you'd like and so you + + align:start position:0% +bit larger than you'd like and so you + + + align:start position:0% +bit larger than you'd like and so you +see a little bit of a freezing point + + align:start position:0% +see a little bit of a freezing point + + + align:start position:0% +see a little bit of a freezing point +depression here all right so now I want + + align:start position:0% +depression here all right so now I want + + + align:start position:0% +depression here all right so now I want +to go back and talk about what's going + + align:start position:0% +to go back and talk about what's going + + + align:start position:0% +to go back and talk about what's going +on inside that uh two-phase regime + + align:start position:0% +on inside that uh two-phase regime + + + align:start position:0% +on inside that uh two-phase regime +because that two-phase regime is is uh + + align:start position:0% +because that two-phase regime is is uh + + + align:start position:0% +because that two-phase regime is is uh +is peculiar it's peculiar so let's see + + align:start position:0% +is peculiar it's peculiar so let's see + + + align:start position:0% +is peculiar it's peculiar so let's see +what happens if we take something of a + + align:start position:0% +what happens if we take something of a + + + align:start position:0% +what happens if we take something of a +particular composition and cool it so + + align:start position:0% +particular composition and cool it so + + + align:start position:0% +particular composition and cool it so +here's what I'm doing I'm going to blow + + align:start position:0% +here's what I'm doing I'm going to blow + + + align:start position:0% +here's what I'm doing I'm going to blow +this up going to blow this up and what I + + align:start position:0% +this up going to blow this up and what I + + + align:start position:0% +this up going to blow this up and what I +want to do is take something that's + + align:start position:0% +want to do is take something that's + + + align:start position:0% +want to do is take something that's +about + + align:start position:0% +about + + + align:start position:0% +about +40% here's where we are we're looking at + + align:start position:0% +40% here's where we are we're looking at + + + align:start position:0% +40% here's where we are we're looking at +this is the liquidous + + align:start position:0% +this is the liquidous + + + align:start position:0% +this is the liquidous +here liquidous line and this is the + + align:start position:0% +here liquidous line and this is the + + + align:start position:0% +here liquidous line and this is the +solidest + + align:start position:0% +solidest + + + align:start position:0% +solidest +line so this is all solid this is single + + align:start position:0% +line so this is all solid this is single + + + align:start position:0% +line so this is all solid this is single +phase P equals 1 this is all + + align:start position:0% + + + + align:start position:0% + +liquid single phase and this is Liquid + + align:start position:0% +liquid single phase and this is Liquid + + + align:start position:0% +liquid single phase and this is Liquid +Plus + + align:start position:0% +Plus + + + align:start position:0% +Plus +solid and let's say we drop the + + align:start position:0% +solid and let's say we drop the + + + align:start position:0% +solid and let's say we drop the +temperature down into the middle of this + + align:start position:0% +temperature down into the middle of this + + + align:start position:0% +temperature down into the middle of this +two-phase regime what's happening here + + align:start position:0% +two-phase regime what's happening here + + + align:start position:0% +two-phase regime what's happening here +this is a two-phase system and we we + + align:start position:0% +this is a two-phase system and we we + + + align:start position:0% +this is a two-phase system and we we +have a liquid and a solid and the phase + + align:start position:0% +have a liquid and a solid and the phase + + + align:start position:0% +have a liquid and a solid and the phase +diagram tells us the composition so + + align:start position:0% +diagram tells us the composition so + + + align:start position:0% +diagram tells us the composition so +here's the sequence here's let's look at + + align:start position:0% +here's the sequence here's let's look at + + + align:start position:0% +here's the sequence here's let's look at +say comp composition uh C2 there + + align:start position:0% +say comp composition uh C2 there + + + align:start position:0% +say comp composition uh C2 there +composition C2 is about + + align:start position:0% +composition C2 is about + + + align:start position:0% +composition C2 is about +40% uh Nickel in Copper so at 1300° C we + + align:start position:0% +40% uh Nickel in Copper so at 1300° C we + + + align:start position:0% +40% uh Nickel in Copper so at 1300° C we +have liquid homogeneous liquid and if we + + align:start position:0% +have liquid homogeneous liquid and if we + + + align:start position:0% +have liquid homogeneous liquid and if we +go down to 1200° + + align:start position:0% +go down to 1200° + + + align:start position:0% +go down to 1200° +C at 1200° C we have a homogeneous solid + + align:start position:0% +C at 1200° C we have a homogeneous solid + + + align:start position:0% +C at 1200° C we have a homogeneous solid +these are the different grains so this + + align:start position:0% +these are the different grains so this + + + align:start position:0% +these are the different grains so this +is liquid this is solid and it's poly + + align:start position:0% + + + + align:start position:0% + +crystallin solid poly crystallin and the + + align:start position:0% +crystallin solid poly crystallin and the + + + align:start position:0% +crystallin solid poly crystallin and the +composition each of these grains is the + + align:start position:0% +composition each of these grains is the + + + align:start position:0% +composition each of these grains is the +same what's happening at + + align:start position:0% +same what's happening at + + + align:start position:0% +same what's happening at +1250 1250 this diagram says I should + + align:start position:0% +1250 1250 this diagram says I should + + + align:start position:0% +1250 1250 this diagram says I should +have solid and liquid solid and liquid + + align:start position:0% +have solid and liquid solid and liquid + + + align:start position:0% +have solid and liquid solid and liquid +but look the composition of that liquid + + align:start position:0% +but look the composition of that liquid + + + align:start position:0% +but look the composition of that liquid +is not + + align:start position:0% +is not + + + align:start position:0% +is not +40% Nickel in Copper the composition is + + align:start position:0% +40% Nickel in Copper the composition is + + + align:start position:0% +40% Nickel in Copper the composition is +way over here it's about + + align:start position:0% +way over here it's about + + + align:start position:0% +way over here it's about +32% and the composition of the solid is + + align:start position:0% +32% and the composition of the solid is + + + align:start position:0% +32% and the composition of the solid is +up here at about 45% + + align:start position:0% +up here at about 45% + + + align:start position:0% +up here at about 45% +% this is + + align:start position:0% +% this is + + + align:start position:0% +% this is +32% uh what am I looking at 32% nickel + + align:start position:0% +32% uh what am I looking at 32% nickel + + + align:start position:0% +32% uh what am I looking at 32% nickel +and this is 45% + + align:start position:0% +and this is 45% + + + align:start position:0% +and this is 45% +nickel so I have a nickel Rich solid and + + align:start position:0% +nickel so I have a nickel Rich solid and + + + align:start position:0% +nickel so I have a nickel Rich solid and +I have a copper Rich liquid there's a + + align:start position:0% +I have a copper Rich liquid there's a + + + align:start position:0% +I have a copper Rich liquid there's a +there's a a shift a + + align:start position:0% +there's a a shift a + + + align:start position:0% +there's a a shift a +shift and suppose I take something of a + + align:start position:0% +shift and suppose I take something of a + + + align:start position:0% +shift and suppose I take something of a +different composition so this is the C2 + + align:start position:0% +different composition so this is the C2 + + + align:start position:0% +different composition so this is the C2 +that's on a diagram here's C1 I think it + + align:start position:0% +that's on a diagram here's C1 I think it + + + align:start position:0% +that's on a diagram here's C1 I think it +starts at around what does it start at + + align:start position:0% +starts at around what does it start at + + + align:start position:0% +starts at around what does it start at +it starts at around 35 5% nickel this + + align:start position:0% +it starts at around 35 5% nickel this + + + align:start position:0% +it starts at around 35 5% nickel this +started at 40% nickel C1 is 35% nickel I + + align:start position:0% +started at 40% nickel C1 is 35% nickel I + + + align:start position:0% +started at 40% nickel C1 is 35% nickel I +cool it down to the same temperature + + align:start position:0% +cool it down to the same temperature + + + align:start position:0% +cool it down to the same temperature +it's the same end members the liquid at + + align:start position:0% +it's the same end members the liquid at + + + align:start position:0% +it's the same end members the liquid at +this temperature has a unique value of + + align:start position:0% +this temperature has a unique value of + + + align:start position:0% +this temperature has a unique value of +nickel content so it doesn't matter what + + align:start position:0% +nickel content so it doesn't matter what + + + align:start position:0% +nickel content so it doesn't matter what +the composition is I will always end up + + align:start position:0% +the composition is I will always end up + + + align:start position:0% +the composition is I will always end up +with a liquid of one composition and a + + align:start position:0% +with a liquid of one composition and a + + + align:start position:0% +with a liquid of one composition and a +solid of the other composition well how + + align:start position:0% +solid of the other composition well how + + + align:start position:0% +solid of the other composition well how +can I start with two different this is + + align:start position:0% +can I start with two different this is + + + align:start position:0% +can I start with two different this is +40% and this is 35 5% nickel 40% nickel + + align:start position:0% +40% and this is 35 5% nickel 40% nickel + + + align:start position:0% +40% and this is 35 5% nickel 40% nickel +35% nickel these end members are the + + align:start position:0% +35% nickel these end members are the + + + align:start position:0% +35% nickel these end members are the +same there's only one variable left it's + + align:start position:0% +same there's only one variable left it's + + + align:start position:0% +same there's only one variable left it's +the relative amounts of these because I + + align:start position:0% +the relative amounts of these because I + + + align:start position:0% +the relative amounts of these because I +need conservation of mass because at the + + align:start position:0% +need conservation of mass because at the + + + align:start position:0% +need conservation of mass because at the +end of the day if I add up all the + + align:start position:0% +end of the day if I add up all the + + + align:start position:0% +end of the day if I add up all the +nickel in the liquid and all the nickel + + align:start position:0% +nickel in the liquid and all the nickel + + + align:start position:0% +nickel in the liquid and all the nickel +in the solid it still has to be net 40% + + align:start position:0% +in the solid it still has to be net 40% + + + align:start position:0% +in the solid it still has to be net 40% +nickel only in here it's 45% nickel up + + align:start position:0% +nickel only in here it's 45% nickel up + + + align:start position:0% +nickel only in here it's 45% nickel up +here it's 32% nickel so I've got a a + + align:start position:0% +here it's 32% nickel so I've got a a + + + align:start position:0% +here it's 32% nickel so I've got a a +verer scale scale I got a sliding scale + + align:start position:0% +verer scale scale I got a sliding scale + + + align:start position:0% +verer scale scale I got a sliding scale +that I can move so that if I have + + align:start position:0% +that I can move so that if I have + + + align:start position:0% +that I can move so that if I have +something that's 35% in other words it's + + align:start position:0% +something that's 35% in other words it's + + + align:start position:0% +something that's 35% in other words it's +got it it needs less of this phase so + + align:start position:0% +got it it needs less of this phase so + + + align:start position:0% +got it it needs less of this phase so +the 35% is going to end up doing this + + align:start position:0% +the 35% is going to end up doing this + + + align:start position:0% +the 35% is going to end up doing this +whereas the 40% is going to end up doing + + align:start position:0% +whereas the 40% is going to end up doing + + + align:start position:0% +whereas the 40% is going to end up doing +this it's the relative amounts this this + + align:start position:0% +this it's the relative amounts this this + + + align:start position:0% +this it's the relative amounts this this +line that tells me what the + + align:start position:0% +line that tells me what the + + + align:start position:0% +line that tells me what the +concentration of the solid and the + + align:start position:0% +concentration of the solid and the + + + align:start position:0% +concentration of the solid and the +liquid at any temperature is called the + + align:start position:0% +liquid at any temperature is called the + + + align:start position:0% +liquid at any temperature is called the +tie line so the ti line defines the + + align:start position:0% +tie line so the ti line defines the + + + align:start position:0% +tie line so the ti line defines the +composition and members the liquid and + + align:start position:0% +composition and members the liquid and + + + align:start position:0% +composition and members the liquid and +the solid in that two phase regime and + + align:start position:0% +the solid in that two phase regime and + + + align:start position:0% +the solid in that two phase regime and +we can take all of this that I've been + + align:start position:0% +we can take all of this that I've been + + + align:start position:0% +we can take all of this that I've been +talking about and we can we can codify + + align:start position:0% +talking about and we can we can codify + + + align:start position:0% +talking about and we can we can codify +it we can codify it in terms of a simple + + align:start position:0% +it we can codify it in terms of a simple + + + align:start position:0% +it we can codify it in terms of a simple +rule that captures the notion of phase + + align:start position:0% +rule that captures the notion of phase + + + align:start position:0% +rule that captures the notion of phase +separation and conservation of mass and + + align:start position:0% +separation and conservation of mass and + + + align:start position:0% +separation and conservation of mass and +that's called the lever + + align:start position:0% +that's called the lever + + + align:start position:0% +that's called the lever +rule the lever rule the lever rule + + align:start position:0% +rule the lever rule the lever rule + + + align:start position:0% +rule the lever rule the lever rule +answers the question how much of each + + align:start position:0% +answers the question how much of each + + + align:start position:0% +answers the question how much of each +phase is present the relative + + align:start position:0% +phase is present the relative + + + align:start position:0% +phase is present the relative +amount relative + + align:start position:0% +amount relative + + + align:start position:0% +amount relative +amount present + + align:start position:0% + + + + align:start position:0% + +of each + + align:start position:0% +of each + + + align:start position:0% +of each +phase in the two-phase + + align:start position:0% + + + + align:start position:0% + +regime in a two-phase + + align:start position:0% +regime in a two-phase + + + align:start position:0% +regime in a two-phase +region two-phase region so for example I + + align:start position:0% +region two-phase region so for example I + + + align:start position:0% +region two-phase region so for example I +think on the next one I've got this set + + align:start position:0% +think on the next one I've got this set + + + align:start position:0% +think on the next one I've got this set +up yeah here it is so here we are with + + align:start position:0% +up yeah here it is so here we are with + + + align:start position:0% +up yeah here it is so here we are with +the 40% nickel it's 40% Nickel in Copper + + align:start position:0% +the 40% nickel it's 40% Nickel in Copper + + + align:start position:0% +the 40% nickel it's 40% Nickel in Copper +we've dropped down into the two-phase + + align:start position:0% +we've dropped down into the two-phase + + + align:start position:0% +we've dropped down into the two-phase +regime draw the tie line and the tie + + align:start position:0% +regime draw the tie line and the tie + + + align:start position:0% +regime draw the tie line and the tie +line tells us that the liquid the liquid + + align:start position:0% +line tells us that the liquid the liquid + + + align:start position:0% +line tells us that the liquid the liquid +will the proportionate as follows so + + align:start position:0% +will the proportionate as follows so + + + align:start position:0% +will the proportionate as follows so +this is + + align:start position:0% +this is + + + align:start position:0% +this is +40% nickel at all + + align:start position:0% +40% nickel at all + + + align:start position:0% +40% nickel at all +liquid all right now we drop the + + align:start position:0% +liquid all right now we drop the + + + align:start position:0% +liquid all right now we drop the +temperature this is 1300 now we drop + + align:start position:0% +temperature this is 1300 now we drop + + + align:start position:0% +temperature this is 1300 now we drop +down to 1250 and we know according to + + align:start position:0% +down to 1250 and we know according to + + + align:start position:0% +down to 1250 and we know according to +the phase diagram we're going to end up + + align:start position:0% +the phase diagram we're going to end up + + + align:start position:0% +the phase diagram we're going to end up +with a liquid and a solid and + + align:start position:0% +with a liquid and a solid and + + + align:start position:0% +with a liquid and a solid and +furthermore from the tie line the tie + + align:start position:0% +furthermore from the tie line the tie + + + align:start position:0% +furthermore from the tie line the tie +line tells us that the solid is going to + + align:start position:0% +line tells us that the solid is going to + + + align:start position:0% +line tells us that the solid is going to +be + + align:start position:0% +be + + + align:start position:0% +be +45% nickel and the liquid is going to be + + align:start position:0% +45% nickel and the liquid is going to be + + + align:start position:0% +45% nickel and the liquid is going to be +32% nickel the question is what are the + + align:start position:0% +32% nickel the question is what are the + + + align:start position:0% +32% nickel the question is what are the +relative values and it just it's shown + + align:start position:0% +relative values and it just it's shown + + + align:start position:0% +relative values and it just it's shown +right up there on the on the uh + + align:start position:0% +right up there on the on the uh + + + align:start position:0% +right up there on the on the uh +transparency that the percent of the + + align:start position:0% +transparency that the percent of the + + + align:start position:0% +transparency that the percent of the +liquid is equal to the in this case the + + align:start position:0% +liquid is equal to the in this case the + + + align:start position:0% +liquid is equal to the in this case the +N member 45 minus the individual amount + + align:start position:0% +N member 45 minus the individual amount + + + align:start position:0% +N member 45 minus the individual amount +at the at the concentration of the bulk + + align:start position:0% +at the at the concentration of the bulk + + + align:start position:0% +at the at the concentration of the bulk +minus the divided by the N members of + + align:start position:0% +minus the divided by the N members of + + + align:start position:0% +minus the divided by the N members of +the tie line we'll multiply that by 100% + + align:start position:0% +the tie line we'll multiply that by 100% + + + align:start position:0% +the tie line we'll multiply that by 100% +And that gives us a value of + + align:start position:0% +And that gives us a value of + + + align:start position:0% +And that gives us a value of +38% present as liquid and why is it + + align:start position:0% +38% present as liquid and why is it + + + align:start position:0% +38% present as liquid and why is it +called the lever rule because if you + + align:start position:0% +called the lever rule because if you + + + align:start position:0% +called the lever rule because if you +look at the tie line here's where we are + + align:start position:0% +look at the tie line here's where we are + + + align:start position:0% +look at the tie line here's where we are +we're at this value which is shown in + + align:start position:0% +we're at this value which is shown in + + + align:start position:0% +we're at this value which is shown in +the phase diagram as uh Z this is our + + align:start position:0% +the phase diagram as uh Z this is our + + + align:start position:0% +the phase diagram as uh Z this is our +40% and the amount of the liquid is X + + align:start position:0% +40% and the amount of the liquid is X + + + align:start position:0% +40% and the amount of the liquid is X +and the amount of the solid is y and so + + align:start position:0% +and the amount of the solid is y and so + + + align:start position:0% +and the amount of the solid is y and so +when I'm asking how much liquid is + + align:start position:0% +when I'm asking how much liquid is + + + align:start position:0% +when I'm asking how much liquid is +present I choose the amount opposite as + + align:start position:0% +present I choose the amount opposite as + + + align:start position:0% +present I choose the amount opposite as +you do on on a on a seesaw or a teeter + + align:start position:0% +you do on on a on a seesaw or a teeter + + + align:start position:0% +you do on on a on a seesaw or a teeter +totter in other words to calculate what + + align:start position:0% +totter in other words to calculate what + + + align:start position:0% +totter in other words to calculate what +the force is here you take the amount + + align:start position:0% +the force is here you take the amount + + + align:start position:0% +the force is here you take the amount +between the fulcrum and the opposite + + align:start position:0% +between the fulcrum and the opposite + + + align:start position:0% +between the fulcrum and the opposite +side divided by the total length so this + + align:start position:0% +side divided by the total length so this + + + align:start position:0% +side divided by the total length so this +is really this is + + align:start position:0% +is really this is + + + align:start position:0% +is really this is +uh YZ over XY gives us liquid and then + + align:start position:0% +uh YZ over XY gives us liquid and then + + + align:start position:0% +uh YZ over XY gives us liquid and then +the complement gives us the amount for + + align:start position:0% +the complement gives us the amount for + + + align:start position:0% +the complement gives us the amount for +solid so you see that worked out for you + + align:start position:0% +solid so you see that worked out for you + + + align:start position:0% +solid so you see that worked out for you +at + + align:start position:0% +at + + + align:start position:0% +at +the on the transparency and this works + + align:start position:0% +the on the transparency and this works + + + align:start position:0% +the on the transparency and this works +for any two-phase regime so whenever + + align:start position:0% +for any two-phase regime so whenever + + + align:start position:0% +for any two-phase regime so whenever +something drops into a two-phase regime + + align:start position:0% +something drops into a two-phase regime + + + align:start position:0% +something drops into a two-phase regime +disproportionation has to occur and the + + align:start position:0% +disproportionation has to occur and the + + + align:start position:0% +disproportionation has to occur and the +lever rule will give you the relative + + align:start position:0% +lever rule will give you the relative + + + align:start position:0% +lever rule will give you the relative +amounts the ti line tells you the + + align:start position:0% +amounts the ti line tells you the + + + align:start position:0% +amounts the ti line tells you the +composition and the lever rule tells you + + align:start position:0% +composition and the lever rule tells you + + + align:start position:0% +composition and the lever rule tells you +the relative amounts two things I want + + align:start position:0% +the relative amounts two things I want + + + align:start position:0% +the relative amounts two things I want +this to be like your you know the that + + align:start position:0% +this to be like your you know the that + + + align:start position:0% +this to be like your you know the that +mansurian candidate you know this is + + align:start position:0% +mansurian candidate you know this is + + + align:start position:0% +mansurian candidate you know this is +your CU if if you from now on if you + + align:start position:0% +your CU if if you from now on if you + + + align:start position:0% +your CU if if you from now on if you +hear two phase you just go lever + + align:start position:0% +hear two phase you just go lever + + + align:start position:0% +hear two phase you just go lever +rule go lever rule lever rule what are + + align:start position:0% +rule go lever rule lever rule what are + + + align:start position:0% +rule go lever rule lever rule what are +the nend members TI line TI line lever + + align:start position:0% +the nend members TI line TI line lever + + + align:start position:0% +the nend members TI line TI line lever +rule TI line lever rule whenever you see + + align:start position:0% +rule TI line lever rule whenever you see + + + align:start position:0% +rule TI line lever rule whenever you see +two-phase + + align:start position:0% +two-phase + + + align:start position:0% +two-phase +regime and it'll keep you out of trouble + + align:start position:0% +regime and it'll keep you out of trouble + + + align:start position:0% +regime and it'll keep you out of trouble +keep you out of trouble I mean many + + align:start position:0% +keep you out of trouble I mean many + + + align:start position:0% +keep you out of trouble I mean many +times I get into trouble and I just + + align:start position:0% +times I get into trouble and I just + + + align:start position:0% +times I get into trouble and I just +think of the lever rule I'm out of + + align:start position:0% +think of the lever rule I'm out of + + + align:start position:0% +think of the lever rule I'm out of +trouble okay + + align:start position:0% +trouble okay + + + align:start position:0% +trouble okay +so now let's look at a second case + + align:start position:0% +so now let's look at a second case + + + align:start position:0% +so now let's look at a second case +second case is type + + align:start position:0% +second case is type + + + align:start position:0% +second case is type +two type two phase diagram type two + + align:start position:0% +two type two phase diagram type two + + + align:start position:0% +two type two phase diagram type two +phase diagram in contrast to complete + + align:start position:0% +phase diagram in contrast to complete + + + align:start position:0% +phase diagram in contrast to complete +solubility type two phas diagram is is + + align:start position:0% +solubility type two phas diagram is is + + + align:start position:0% +solubility type two phas diagram is is +characterized by system that has + + align:start position:0% +characterized by system that has + + + align:start position:0% +characterized by system that has +partial partial or + + align:start position:0% +partial partial or + + + align:start position:0% +partial partial or +limited or limited + + align:start position:0% +limited or limited + + + align:start position:0% +limited or limited +solubility so when you try to mix A and + + align:start position:0% +solubility so when you try to mix A and + + + align:start position:0% +solubility so when you try to mix A and +B they don't mix in all proportions they + + align:start position:0% +B they don't mix in all proportions they + + + align:start position:0% +B they don't mix in all proportions they +only mix up to a certain point so that's + + align:start position:0% +only mix up to a certain point so that's + + + align:start position:0% +only mix up to a certain point so that's +like a solubility limit or a missil + + align:start position:0% +like a solubility limit or a missil + + + align:start position:0% +like a solubility limit or a missil +missil or solubility synonymous this + + align:start position:0% +missil or solubility synonymous this + + + align:start position:0% +missil or solubility synonymous this +leads to a missil Gap a range of + + align:start position:0% +leads to a missil Gap a range of + + + align:start position:0% +leads to a missil Gap a range of +composition over which you can't mix the + + align:start position:0% +composition over which you can't mix the + + + align:start position:0% +composition over which you can't mix the +two of them and form a homogeneous + + align:start position:0% +two of them and form a homogeneous + + + align:start position:0% +two of them and form a homogeneous +solution and in this case there's no + + align:start position:0% +solution and in this case there's no + + + align:start position:0% +solution and in this case there's no +change of + + align:start position:0% +change of + + + align:start position:0% +change of +state no change of state so that's + + align:start position:0% +state no change of state so that's + + + align:start position:0% +state no change of state so that's +either always + + align:start position:0% + + + + align:start position:0% + +liquid always liquid or always + + align:start position:0% +liquid always liquid or always + + + align:start position:0% +liquid always liquid or always +solid always + + align:start position:0% +solid always + + + align:start position:0% +solid always +solid so let's look at the phase diagram + + align:start position:0% +solid so let's look at the phase diagram + + + align:start position:0% +solid so let's look at the phase diagram +for one of these type of systems + + align:start position:0% +for one of these type of systems + + + align:start position:0% +for one of these type of systems +a b I'm plotting composition across the + + align:start position:0% +a b I'm plotting composition across the + + + align:start position:0% +a b I'm plotting composition across the +uh abscissa the ordinate is + + align:start position:0% +uh abscissa the ordinate is + + + align:start position:0% +uh abscissa the ordinate is +temperature and this gives us a + + align:start position:0% +temperature and this gives us a + + + align:start position:0% +temperature and this gives us a +synclinal phase diagram a synclinal + + align:start position:0% +synclinal phase diagram a synclinal + + + align:start position:0% +synclinal phase diagram a synclinal +phase diagram so above we have single + + align:start position:0% +phase diagram so above we have single + + + align:start position:0% +phase diagram so above we have single +phase so this is either want to just say + + align:start position:0% +phase so this is either want to just say + + + align:start position:0% +phase so this is either want to just say +single + + align:start position:0% +single + + + align:start position:0% +single +phase and this is dual + + align:start position:0% + + + + align:start position:0% + +phase dual phase single phase dual phase + + align:start position:0% +phase dual phase single phase dual phase + + + align:start position:0% +phase dual phase single phase dual phase +so for example this could be a solid + + align:start position:0% +so for example this could be a solid + + + align:start position:0% +so for example this could be a solid +this could be all liquid and then in + + align:start position:0% +this could be all liquid and then in + + + align:start position:0% +this could be all liquid and then in +here we have two + + align:start position:0% + + + + align:start position:0% + +liquids or it could be all solid and + + align:start position:0% +liquids or it could be all solid and + + + align:start position:0% +liquids or it could be all solid and +inside here we have two solids when it + + align:start position:0% +inside here we have two solids when it + + + align:start position:0% +inside here we have two solids when it +comes to solid Solutions people use + + align:start position:0% +comes to solid Solutions people use + + + align:start position:0% +comes to solid Solutions people use +Greek letters and call this Alpha and + + align:start position:0% +Greek letters and call this Alpha and + + + align:start position:0% +Greek letters and call this Alpha and +beta so this is the coexistence + + align:start position:0% + + + + align:start position:0% + +curve or the solubility limit what's the + + align:start position:0% +curve or the solubility limit what's the + + + align:start position:0% +curve or the solubility limit what's the +coexistence curve the coexistence curve + + align:start position:0% +coexistence curve the coexistence curve + + + align:start position:0% +coexistence curve the coexistence curve +is liquid is an equilibrium with liquid + + align:start position:0% +is liquid is an equilibrium with liquid + + + align:start position:0% +is liquid is an equilibrium with liquid +one and liquid 2 in other words if you + + align:start position:0% +one and liquid 2 in other words if you + + + align:start position:0% +one and liquid 2 in other words if you +drop into this two-phase regime what + + align:start position:0% +drop into this two-phase regime what + + + align:start position:0% +drop into this two-phase regime what +happens as soon as you hear + + align:start position:0% + + + + align:start position:0% + +two-phase TI line lever rule the ti line + + align:start position:0% +two-phase TI line lever rule the ti line + + + align:start position:0% +two-phase TI line lever rule the ti line +will give you the concentrations at the + + align:start position:0% +will give you the concentrations at the + + + align:start position:0% +will give you the concentrations at the +end or solid goes to Alpha plus beta + + align:start position:0% +end or solid goes to Alpha plus beta + + + align:start position:0% +end or solid goes to Alpha plus beta +both of these are solid + + align:start position:0% +both of these are solid + + + align:start position:0% +both of these are solid +Solutions let's take a look at at some + + align:start position:0% +Solutions let's take a look at at some + + + align:start position:0% +Solutions let's take a look at at some +of + + align:start position:0% + + + + align:start position:0% + +these this is gold nickel at low + + align:start position:0% +these this is gold nickel at low + + + align:start position:0% +these this is gold nickel at low +temperatures look what happens at low + + align:start position:0% +temperatures look what happens at low + + + align:start position:0% +temperatures look what happens at low +temperatures gold nickel will actually + + align:start position:0% +temperatures gold nickel will actually + + + align:start position:0% +temperatures gold nickel will actually +phase separate so if you take something + + align:start position:0% +phase separate so if you take something + + + align:start position:0% +phase separate so if you take something +like uh this one here which is 50 we% + + align:start position:0% +like uh this one here which is 50 we% + + + align:start position:0% +like uh this one here which is 50 we% +nickel drop at high temperatures they + + align:start position:0% +nickel drop at high temperatures they + + + align:start position:0% +nickel drop at high temperatures they +mix in all proportions drop into here we + + align:start position:0% +mix in all proportions drop into here we + + + align:start position:0% +mix in all proportions drop into here we +have a slush consisting of liquid and + + align:start position:0% +have a slush consisting of liquid and + + + align:start position:0% +have a slush consisting of liquid and +solid and they have different + + align:start position:0% +solid and they have different + + + align:start position:0% +solid and they have different +compositions given by the Tha line drop + + align:start position:0% +compositions given by the Tha line drop + + + align:start position:0% +compositions given by the Tha line drop +even lower in temperature and all of a + + align:start position:0% +even lower in temperature and all of a + + + align:start position:0% +even lower in temperature and all of a +sudden it's a single- face solid + + align:start position:0% +sudden it's a single- face solid + + + align:start position:0% +sudden it's a single- face solid +solution FCC lattice with golden nickel + + align:start position:0% +solution FCC lattice with golden nickel + + + align:start position:0% +solution FCC lattice with golden nickel +atoms 50/50 well in this case it's + + align:start position:0% +atoms 50/50 well in this case it's + + + align:start position:0% +atoms 50/50 well in this case it's +weight percent so it's not exactly on an + + align:start position:0% +weight percent so it's not exactly on an + + + align:start position:0% +weight percent so it's not exactly on an +atomic basis there it's about 75 and + + align:start position:0% +atomic basis there it's about 75 and + + + align:start position:0% +atomic basis there it's about 75 and +then we drop into lower temperatures and + + align:start position:0% +then we drop into lower temperatures and + + + align:start position:0% +then we drop into lower temperatures and +now they face separate so we end up it's + + align:start position:0% +now they face separate so we end up it's + + + align:start position:0% +now they face separate so we end up it's +for example at 600° let's get down to + + align:start position:0% +for example at 600° let's get down to + + + align:start position:0% +for example at 600° let's get down to +say room temperature this is uh 300° C + + align:start position:0% +say room temperature this is uh 300° C + + + align:start position:0% +say room temperature this is uh 300° C +but the lines are starting to get fairly + + align:start position:0% +but the lines are starting to get fairly + + + align:start position:0% +but the lines are starting to get fairly +steep what you find is that it'll phase + + align:start position:0% +steep what you find is that it'll phase + + + align:start position:0% +steep what you find is that it'll phase +separate so that you'll end up with + + align:start position:0% +separate so that you'll end up with + + + align:start position:0% +separate so that you'll end up with +zones that are nickel rich and zones + + align:start position:0% +zones that are nickel rich and zones + + + align:start position:0% +zones that are nickel rich and zones +that are gold rich and the ti line tells + + align:start position:0% +that are gold rich and the ti line tells + + + align:start position:0% +that are gold rich and the ti line tells +you the concentr the composition I of + + align:start position:0% +you the concentr the composition I of + + + align:start position:0% +you the concentr the composition I of +both of those and members here's one + + align:start position:0% +both of those and members here's one + + + align:start position:0% +both of those and members here's one +hexane + + align:start position:0% +hexane + + + align:start position:0% +hexane +nitrobenzene at high temperatures they + + align:start position:0% +nitrobenzene at high temperatures they + + + align:start position:0% +nitrobenzene at high temperatures they +mix in all proportions you drop the + + align:start position:0% +mix in all proportions you drop the + + + align:start position:0% +mix in all proportions you drop the +temperature and then they phase separate + + align:start position:0% +temperature and then they phase separate + + + align:start position:0% +temperature and then they phase separate +just as oil and water so down at this + + align:start position:0% +just as oil and water so down at this + + + align:start position:0% +just as oil and water so down at this +temperature you will have a hexane Rich + + align:start position:0% +temperature you will have a hexane Rich + + + align:start position:0% +temperature you will have a hexane Rich +phase and a Nitro Benzene Rich phase and + + align:start position:0% +phase and a Nitro Benzene Rich phase and + + + align:start position:0% +phase and a Nitro Benzene Rich phase and +the lower and lower you get in + + align:start position:0% +the lower and lower you get in + + + align:start position:0% +the lower and lower you get in +temperature the greater that separation + + align:start position:0% +temperature the greater that separation + + + align:start position:0% +temperature the greater that separation +think about it at this constant + + align:start position:0% +think about it at this constant + + + align:start position:0% +think about it at this constant +temperature what this is saying is that + + align:start position:0% +temperature what this is saying is that + + + align:start position:0% +temperature what this is saying is that +you can put a certain amount of nitro + + align:start position:0% +you can put a certain amount of nitro + + + align:start position:0% +you can put a certain amount of nitro +Benzene into hexane and that's the + + align:start position:0% +Benzene into hexane and that's the + + + align:start position:0% +Benzene into hexane and that's the +solubility limit if you try to put any + + align:start position:0% +solubility limit if you try to put any + + + align:start position:0% +solubility limit if you try to put any +more nitrobenzene into hexane it won't + + align:start position:0% +more nitrobenzene into hexane it won't + + + align:start position:0% +more nitrobenzene into hexane it won't +go in on the other side it says you can + + align:start position:0% +go in on the other side it says you can + + + align:start position:0% +go in on the other side it says you can +put a small amount of hexane and + + align:start position:0% +put a small amount of hexane and + + + align:start position:0% +put a small amount of hexane and +nitrobenzene if you try to put anymore + + align:start position:0% +nitrobenzene if you try to put anymore + + + align:start position:0% +nitrobenzene if you try to put anymore +it won't go in it'll just precipitate + + align:start position:0% +it won't go in it'll just precipitate + + + align:start position:0% +it won't go in it'll just precipitate +out and furthermore this makes sense to + + align:start position:0% +out and furthermore this makes sense to + + + align:start position:0% +out and furthermore this makes sense to +you doesn't it at this temperature I can + + align:start position:0% +you doesn't it at this temperature I can + + + align:start position:0% +you doesn't it at this temperature I can +put say 0.1 units of nitrobenzene if I + + align:start position:0% +put say 0.1 units of nitrobenzene if I + + + align:start position:0% +put say 0.1 units of nitrobenzene if I +raise the temperature the solubility + + align:start position:0% +raise the temperature the solubility + + + align:start position:0% +raise the temperature the solubility +goes up with temperature all of this is + + align:start position:0% +goes up with temperature all of this is + + + align:start position:0% +goes up with temperature all of this is +making sense and finally you get to a + + align:start position:0% +making sense and finally you get to a + + + align:start position:0% +making sense and finally you get to a +temperature here above which they mix in + + align:start position:0% +temperature here above which they mix in + + + align:start position:0% +temperature here above which they mix in +all proportions and this temperature is + + align:start position:0% +all proportions and this temperature is + + + align:start position:0% +all proportions and this temperature is +called the + + align:start position:0% +called the + + + align:start position:0% +called the +consolute consolute temperature above + + align:start position:0% +consolute consolute temperature above + + + align:start position:0% +consolute consolute temperature above +the consolute temperature even a system + + align:start position:0% +the consolute temperature even a system + + + align:start position:0% +the consolute temperature even a system +that has a propensity for limited + + align:start position:0% +that has a propensity for limited + + + align:start position:0% +that has a propensity for limited +solubility will mix in all proportions + + align:start position:0% +solubility will mix in all proportions + + + align:start position:0% +solubility will mix in all proportions +so you see this in uh different systems + + align:start position:0% +so you see this in uh different systems + + + align:start position:0% +so you see this in uh different systems +here's look this one's a surprise this + + align:start position:0% +here's look this one's a surprise this + + + align:start position:0% +here's look this one's a surprise this +is two Alkali halides sodium chloride + + align:start position:0% +is two Alkali halides sodium chloride + + + align:start position:0% +is two Alkali halides sodium chloride +and potassium chloride you'd expect + + align:start position:0% +and potassium chloride you'd expect + + + align:start position:0% +and potassium chloride you'd expect +those to just trade off with one another + + align:start position:0% +those to just trade off with one another + + + align:start position:0% +those to just trade off with one another +but there's a problem here the sodium + + align:start position:0% +but there's a problem here the sodium + + + align:start position:0% +but there's a problem here the sodium +ion and the potassium ion are different + + align:start position:0% +ion and the potassium ion are different + + + align:start position:0% +ion and the potassium ion are different +enough in atomic Dimension different + + align:start position:0% +enough in atomic Dimension different + + + align:start position:0% +enough in atomic Dimension different +enough in charge density that as you get + + align:start position:0% +enough in charge density that as you get + + + align:start position:0% +enough in charge density that as you get +to low temperatures they phas separate + + align:start position:0% +to low temperatures they phas separate + + + align:start position:0% +to low temperatures they phas separate +they face separate so instead of making + + align:start position:0% +they face separate so instead of making + + + align:start position:0% +they face separate so instead of making +a perfect solid solution at lower + + align:start position:0% +a perfect solid solution at lower + + + align:start position:0% +a perfect solid solution at lower +temperatures the single-phase solid + + align:start position:0% +temperatures the single-phase solid + + + align:start position:0% +temperatures the single-phase solid +solution breaks into a potassium rich + + align:start position:0% +solution breaks into a potassium rich + + + align:start position:0% +solution breaks into a potassium rich +solid solution and a sodium Rich solid + + align:start position:0% +solid solution and a sodium Rich solid + + + align:start position:0% +solid solution and a sodium Rich solid +solution here's from the polymer world + + align:start position:0% +solution here's from the polymer world + + + align:start position:0% +solution here's from the polymer world +this one is polystyrene polybutadiene + + align:start position:0% +this one is polystyrene polybutadiene + + + align:start position:0% +this one is polystyrene polybutadiene +at high temperatures you can mix them + + align:start position:0% +at high temperatures you can mix them + + + align:start position:0% +at high temperatures you can mix them +make a + + align:start position:0% +make a + + + align:start position:0% +make a +co-polymer a co- polymer mix in all + + align:start position:0% +co-polymer a co- polymer mix in all + + + align:start position:0% +co-polymer a co- polymer mix in all +proportions as you drop the temperature + + align:start position:0% +proportions as you drop the temperature + + + align:start position:0% +proportions as you drop the temperature +they will phase separate and you'll end + + align:start position:0% +they will phase separate and you'll end + + + align:start position:0% +they will phase separate and you'll end +up with something that is islands of a + + align:start position:0% +up with something that is islands of a + + + align:start position:0% +up with something that is islands of a +polystyrene Rich phase not pure + + align:start position:0% +polystyrene Rich phase not pure + + + align:start position:0% +polystyrene Rich phase not pure +polystyrene there's a certain amount of + + align:start position:0% +polystyrene there's a certain amount of + + + align:start position:0% +polystyrene there's a certain amount of +polybutene in it and then the other + + align:start position:0% +polybutene in it and then the other + + + align:start position:0% +polybutene in it and then the other +phase will be polyad with a certain + + align:start position:0% +phase will be polyad with a certain + + + align:start position:0% +phase will be polyad with a certain +amount of polystyrene they phase + + align:start position:0% +amount of polystyrene they phase + + + align:start position:0% +amount of polystyrene they phase +separate here's one certain systems + + align:start position:0% +separate here's one certain systems + + + align:start position:0% +separate here's one certain systems +instead of exhibiting a consolute + + align:start position:0% +instead of exhibiting a consolute + + + align:start position:0% +instead of exhibiting a consolute +temperature in this fashion for entropic + + align:start position:0% +temperature in this fashion for entropic + + + align:start position:0% +temperature in this fashion for entropic +reasons the system is flipped upside + + align:start position:0% +reasons the system is flipped upside + + + align:start position:0% +reasons the system is flipped upside +down so this is a lower critical + + align:start position:0% +down so this is a lower critical + + + align:start position:0% +down so this is a lower critical +temperature this is weird because + + align:start position:0% +temperature this is weird because + + + align:start position:0% +temperature this is weird because +normally you think as you raise + + align:start position:0% +normally you think as you raise + + + align:start position:0% +normally you think as you raise +temperature you increase solubility this + + align:start position:0% +temperature you increase solubility this + + + align:start position:0% +temperature you increase solubility this +one case where it does it goes the + + align:start position:0% +one case where it does it goes the + + + align:start position:0% +one case where it does it goes the +inverse so water triethylamine mixes in + + align:start position:0% +inverse so water triethylamine mixes in + + + align:start position:0% +inverse so water triethylamine mixes in +all proportions at low temperature at + + align:start position:0% +all proportions at low temperature at + + + align:start position:0% +all proportions at low temperature at +higher temperatures there's the so + + align:start position:0% +higher temperatures there's the so + + + align:start position:0% +higher temperatures there's the so +instead of being synclinal this is + + align:start position:0% +instead of being synclinal this is + + + align:start position:0% +instead of being synclinal this is +anticlinal It's a U-shaped curve so + + align:start position:0% +anticlinal It's a U-shaped curve so + + + align:start position:0% +anticlinal It's a U-shaped curve so +single phase out here down here they mix + + align:start position:0% +single phase out here down here they mix + + + align:start position:0% +single phase out here down here they mix +in all proportions up here you can put a + + align:start position:0% +in all proportions up here you can put a + + + align:start position:0% +in all proportions up here you can put a +certain amount of triethylamine in and + + align:start position:0% +certain amount of triethylamine in and + + + align:start position:0% +certain amount of triethylamine in and +then it stops then you get the second + + align:start position:0% +then it stops then you get the second + + + align:start position:0% +then it stops then you get the second +phase now here's the weirdest one of all + + align:start position:0% +phase now here's the weirdest one of all + + + align:start position:0% +phase now here's the weirdest one of all +this is nicotine and water it has an + + align:start position:0% +this is nicotine and water it has an + + + align:start position:0% +this is nicotine and water it has an +upper critical uh point and a lower + + align:start position:0% +upper critical uh point and a lower + + + align:start position:0% +upper critical uh point and a lower +critical point so at low temperatures + + align:start position:0% +critical point so at low temperatures + + + align:start position:0% +critical point so at low temperatures +you can mix nicotine and water in all + + align:start position:0% +you can mix nicotine and water in all + + + align:start position:0% +you can mix nicotine and water in all +proportions and at very high + + align:start position:0% +proportions and at very high + + + align:start position:0% +proportions and at very high +temperatures you can mix nicotine and + + align:start position:0% +temperatures you can mix nicotine and + + + align:start position:0% +temperatures you can mix nicotine and +water in all proportions and at + + align:start position:0% +water in all proportions and at + + + align:start position:0% +water in all proportions and at +intermediate temperatures they face + + align:start position:0% +intermediate temperatures they face + + + align:start position:0% +intermediate temperatures they face +separate there's the map that tells you + + align:start position:0% +separate there's the map that tells you + + + align:start position:0% +separate there's the map that tells you +how the system behaves as a function of + + align:start position:0% +how the system behaves as a function of + + + align:start position:0% +how the system behaves as a function of +temperature and composition so in here + + align:start position:0% +temperature and composition so in here + + + align:start position:0% +temperature and composition so in here +you can't get the you can't get a + + align:start position:0% +you can't get the you can't get a + + + align:start position:0% +you can't get the you can't get a +homogeneous solution if you try to make + + align:start position:0% +homogeneous solution if you try to make + + + align:start position:0% +homogeneous solution if you try to make +a 50/50 mix of water and nicotine and + + align:start position:0% +a 50/50 mix of water and nicotine and + + + align:start position:0% +a 50/50 mix of water and nicotine and +you heat that to 100° C it'll phas + + align:start position:0% +you heat that to 100° C it'll phas + + + align:start position:0% +you heat that to 100° C it'll phas +separate you will not even though you'll + + align:start position:0% +separate you will not even though you'll + + + align:start position:0% +separate you will not even though you'll +mix it at room temperature and it'll be + + align:start position:0% +mix it at room temperature and it'll be + + + align:start position:0% +mix it at room temperature and it'll be +homogeneous as you raise the temperature + + align:start position:0% +homogeneous as you raise the temperature + + + align:start position:0% +homogeneous as you raise the temperature +all of a sudden you'll see milkiness + + align:start position:0% +all of a sudden you'll see milkiness + + + align:start position:0% +all of a sudden you'll see milkiness +Globs of one forming in the other so + + align:start position:0% +Globs of one forming in the other so + + + align:start position:0% +Globs of one forming in the other so +what would happen if we were to take 60% + + align:start position:0% +what would happen if we were to take 60% + + + align:start position:0% +what would happen if we were to take 60% +sodium chloride and cool it down to say + + align:start position:0% +sodium chloride and cool it down to say + + + align:start position:0% +sodium chloride and cool it down to say +400 degrees C what happens bingo + + align:start position:0% +400 degrees C what happens bingo + + + align:start position:0% +400 degrees C what happens bingo +TI line P equals 2 so the homogeneous + + align:start position:0% +TI line P equals 2 so the homogeneous + + + align:start position:0% +TI line P equals 2 so the homogeneous +solid solution breaks into an alpha + + align:start position:0% +solid solution breaks into an alpha + + + align:start position:0% +solid solution breaks into an alpha +which is the designation for the + + align:start position:0% +which is the designation for the + + + align:start position:0% +which is the designation for the +potassium chloride Rich solid solution + + align:start position:0% +potassium chloride Rich solid solution + + + align:start position:0% +potassium chloride Rich solid solution +and beta which is the designation for + + align:start position:0% +and beta which is the designation for + + + align:start position:0% +and beta which is the designation for +the sodium chloride Rich solid solution + + align:start position:0% +the sodium chloride Rich solid solution + + + align:start position:0% +the sodium chloride Rich solid solution +and how do we figure out the relative + + align:start position:0% +and how do we figure out the relative + + + align:start position:0% +and how do we figure out the relative +amounts of Alpha and + + align:start position:0% +amounts of Alpha and + + + align:start position:0% +amounts of Alpha and +beta lever rule it's a two-phase regime + + align:start position:0% +beta lever rule it's a two-phase regime + + + align:start position:0% +beta lever rule it's a two-phase regime +lever rule that's it that's + + align:start position:0% +lever rule that's it that's + + + align:start position:0% +lever rule that's it that's +it so now what I want to I do a little + + align:start position:0% +it so now what I want to I do a little + + + align:start position:0% +it so now what I want to I do a little +experiment here show you how this works + + align:start position:0% +experiment here show you how this works + + + align:start position:0% +experiment here show you how this works +so I'm going to work with a simple + + align:start position:0% +so I'm going to work with a simple + + + align:start position:0% +so I'm going to work with a simple +system this is oo and water oo is a + + align:start position:0% +system this is oo and water oo is a + + + align:start position:0% +system this is oo and water oo is a +drink it's a lure from the absent family + + align:start position:0% +drink it's a lure from the absent family + + + align:start position:0% +drink it's a lure from the absent family +and the wormwood is the chief flavoring + + align:start position:0% +and the wormwood is the chief flavoring + + + align:start position:0% +and the wormwood is the chief flavoring +agent it contains licorice hop fennel + + align:start position:0% +agent it contains licorice hop fennel + + + align:start position:0% +agent it contains licorice hop fennel +Angelica root an AED so the thing is + + align:start position:0% +Angelica root an AED so the thing is + + + align:start position:0% +Angelica root an AED so the thing is +it's got a lot of oil in it it's very + + align:start position:0% +it's got a lot of oil in it it's very + + + align:start position:0% +it's got a lot of oil in it it's very +oily it's clear and colorless but it's + + align:start position:0% +oily it's clear and colorless but it's + + + align:start position:0% +oily it's clear and colorless but it's +very + + align:start position:0% +very + + + align:start position:0% +very +oily and then water of course you know + + align:start position:0% +oily and then water of course you know + + + align:start position:0% +oily and then water of course you know +what water is so let's have a look Tom + + align:start position:0% +what water is so let's have a look Tom + + + align:start position:0% +what water is so let's have a look Tom +can we cut to the document camera + + align:start position:0% +can we cut to the document camera + + + align:start position:0% +can we cut to the document camera +here so what I'm going to do what I'm + + align:start position:0% +here so what I'm going to do what I'm + + + align:start position:0% +here so what I'm going to do what I'm +I'm going to do is I'm going + + align:start position:0% + + + + align:start position:0% + +to here's + + align:start position:0% +to here's + + + align:start position:0% +to here's +water and here's uzo and these are at + + align:start position:0% +water and here's uzo and these are at + + + align:start position:0% +water and here's uzo and these are at +room temperature and I'm assuming the + + align:start position:0% +room temperature and I'm assuming the + + + align:start position:0% +room temperature and I'm assuming the +phase diagram looks like this I can put + + align:start position:0% +phase diagram looks like this I can put + + + align:start position:0% +phase diagram looks like this I can put +a little bit of uzo into water and I can + + align:start position:0% +a little bit of uzo into water and I can + + + align:start position:0% +a little bit of uzo into water and I can +put a little bit of water into oo but if + + align:start position:0% +put a little bit of water into oo but if + + + align:start position:0% +put a little bit of water into oo but if +I exceed these solubility limits in here + + align:start position:0% +I exceed these solubility limits in here + + + align:start position:0% +I exceed these solubility limits in here +this is milky because it's two phase + + align:start position:0% +this is milky because it's two phase + + + align:start position:0% +this is milky because it's two phase +this is milky and this is clear why + + align:start position:0% +this is milky and this is clear why + + + align:start position:0% +this is milky and this is clear why +because this is single phase + + align:start position:0% +because this is single phase + + + align:start position:0% +because this is single phase +and this is p equal 2 so we're going to + + align:start position:0% +and this is p equal 2 so we're going to + + + align:start position:0% +and this is p equal 2 so we're going to +do an experiment here so what I'm going + + align:start position:0% +do an experiment here so what I'm going + + + align:start position:0% +do an experiment here so what I'm going +to do is I'm going to put just this is + + align:start position:0% +to do is I'm going to put just this is + + + align:start position:0% +to do is I'm going to put just this is +just pure water you know what pure water + + align:start position:0% +just pure water you know what pure water + + + align:start position:0% +just pure water you know what pure water +looks like so that's pure water + + align:start position:0% +looks like so that's pure water + + + align:start position:0% +looks like so that's pure water +distilled water and here's some + + align:start position:0% +distilled water and here's some + + + align:start position:0% +distilled water and here's some +oo and this is clear and colorless as + + align:start position:0% + + + + align:start position:0% + +well clear and colorless okay so now + + align:start position:0% +well clear and colorless okay so now + + + align:start position:0% +well clear and colorless okay so now +what I'm going to do is I'm going to + + align:start position:0% +what I'm going to do is I'm going to + + + align:start position:0% +what I'm going to do is I'm going to +pour uh water + + align:start position:0% +pour uh water + + + align:start position:0% +pour uh water +into the oo + + align:start position:0% + + + + align:start position:0% + +see if I pour a little bit in I can stir + + align:start position:0% +see if I pour a little bit in I can stir + + + align:start position:0% +see if I pour a little bit in I can stir +this and it will dissolve but if I pour + + align:start position:0% +this and it will dissolve but if I pour + + + align:start position:0% +this and it will dissolve but if I pour +so what I'm doing here is I'm pouring + + align:start position:0% +so what I'm doing here is I'm pouring + + + align:start position:0% +so what I'm doing here is I'm pouring +water into uzo and I'm coming across if + + align:start position:0% +water into uzo and I'm coming across if + + + align:start position:0% +water into uzo and I'm coming across if +I pour too much water in I'm going to + + align:start position:0% +I pour too much water in I'm going to + + + align:start position:0% +I pour too much water in I'm going to +hit this myability Gap and this will + + align:start position:0% +hit this myability Gap and this will + + + align:start position:0% +hit this myability Gap and this will +precipitate out and when it precipitates + + align:start position:0% +precipitate out and when it precipitates + + + align:start position:0% +precipitate out and when it precipitates +out it's got a different index it's + + align:start position:0% +out it's got a different index it's + + + align:start position:0% +out it's got a different index it's +going to look milky in fact I think I've + + align:start position:0% +going to look milky in fact I think I've + + + align:start position:0% +going to look milky in fact I think I've +already hit there look at + + align:start position:0% +already hit there look at + + + align:start position:0% +already hit there look at +this all right so I've crossed the Miss + + align:start position:0% +this all right so I've crossed the Miss + + + align:start position:0% +this all right so I've crossed the Miss +ability + + align:start position:0% +ability + + + align:start position:0% +ability +Gap now if if my hunch is correct I + + align:start position:0% +Gap now if if my hunch is correct I + + + align:start position:0% +Gap now if if my hunch is correct I +should be able to keep adding water and + + align:start position:0% +should be able to keep adding water and + + + align:start position:0% +should be able to keep adding water and +eventually emerge on this side so let's + + align:start position:0% +eventually emerge on this side so let's + + + align:start position:0% +eventually emerge on this side so let's +see what + + align:start position:0% + + + + align:start position:0% + +happens so we'll dilute it so I'm going + + align:start position:0% +happens so we'll dilute it so I'm going + + + align:start position:0% +happens so we'll dilute it so I'm going +to pour this down to + + align:start position:0% + + + + align:start position:0% + +almost tiny fraction now we'll pour in + + align:start position:0% +almost tiny fraction now we'll pour in + + + align:start position:0% +almost tiny fraction now we'll pour in +more there + + align:start position:0% +more there + + + align:start position:0% +more there +so I've crossed the Miss ability Gap + + align:start position:0% +so I've crossed the Miss ability Gap + + + align:start position:0% +so I've crossed the Miss ability Gap +right I can do it the other way let's + + align:start position:0% +right I can do it the other way let's + + + align:start position:0% +right I can do it the other way let's +start with uh water we can go across oh + + align:start position:0% +start with uh water we can go across oh + + + align:start position:0% +start with uh water we can go across oh +we can do the other it doesn't matter + + align:start position:0% +we can do the other it doesn't matter + + + align:start position:0% +we can do the other it doesn't matter +okay so now what's the what's the + + align:start position:0% +okay so now what's the what's the + + + align:start position:0% +okay so now what's the what's the +difference between this and absent absen + + align:start position:0% +difference between this and absent absen + + + align:start position:0% +difference between this and absent absen +is similar but it's + + align:start position:0% +is similar but it's + + + align:start position:0% +is similar but it's +uh it's got uh a little more color to + + align:start position:0% + + + + align:start position:0% + +it AB santh is + + align:start position:0% + + + + align:start position:0% + +green and this the same kind of a + + align:start position:0% +green and this the same kind of a + + + align:start position:0% +green and this the same kind of a +and so when you add water to Aban you're + + align:start position:0% +and so when you add water to Aban you're + + + align:start position:0% +and so when you add water to Aban you're +supposed to add it five parts water and + + align:start position:0% +supposed to add it five parts water and + + + align:start position:0% +supposed to add it five parts water and +one + + align:start position:0% + + + + align:start position:0% + +part cuz we're going to make the Louch + + align:start position:0% +part cuz we're going to make the Louch + + + align:start position:0% +part cuz we're going to make the Louch +which is the + + align:start position:0% + + + + align:start position:0% + +Milky okay this is the way Aban would be + + align:start position:0% +Milky okay this is the way Aban would be + + + align:start position:0% +Milky okay this is the way Aban would be +drunk uh let's see pour this into here + + align:start position:0% + + + + align:start position:0% + +so you can see how milky this is now + + align:start position:0% +so you can see how milky this is now + + + align:start position:0% +so you can see how milky this is now +when tus lat Trek drank he called he + + align:start position:0% +when tus lat Trek drank he called he + + + align:start position:0% +when tus lat Trek drank he called he +made a drink called the earthquake what + + align:start position:0% +made a drink called the earthquake what + + + align:start position:0% +made a drink called the earthquake what +he did with the earthquake is he added + + align:start position:0% +he did with the earthquake is he added + + + align:start position:0% +he did with the earthquake is he added +cognac he added cognac to the absen + + align:start position:0% +cognac he added cognac to the absen + + + align:start position:0% +cognac he added cognac to the absen +Louch all right so what are we going to + + align:start position:0% +Louch all right so what are we going to + + + align:start position:0% +Louch all right so what are we going to +do here what's the chemistry the + + align:start position:0% +do here what's the chemistry the + + + align:start position:0% +do here what's the chemistry the +chemistry is the following I've got oil + + align:start position:0% +chemistry is the following I've got oil + + + align:start position:0% +chemistry is the following I've got oil +droplets here in water okay oil and then + + align:start position:0% +droplets here in water okay oil and then + + + align:start position:0% +droplets here in water okay oil and then +over here is + + align:start position:0% +over here is + + + align:start position:0% +over here is +water what I'm going to do is I'm going + + align:start position:0% +water what I'm going to do is I'm going + + + align:start position:0% +water what I'm going to do is I'm going +to put ethyl alcohol ch3 + + align:start position:0% +to put ethyl alcohol ch3 + + + align:start position:0% +to put ethyl alcohol ch3 +ch2 and what does the O do the + + align:start position:0% + + + + align:start position:0% + +O makes a hydrogen + + align:start position:0% +O makes a hydrogen + + + align:start position:0% +O makes a hydrogen +bond so I've got a hydrophilic + + align:start position:0% +bond so I've got a hydrophilic + + + align:start position:0% +bond so I've got a hydrophilic +head got a hydrophilic + + align:start position:0% +head got a hydrophilic + + + align:start position:0% +head got a hydrophilic +head right ethyl alcohol is amphipathic + + align:start position:0% +head right ethyl alcohol is amphipathic + + + align:start position:0% +head right ethyl alcohol is amphipathic +and this is a hydrophobic + + align:start position:0% + + + + align:start position:0% + +tail hydrophobic tail so the hydrophobic + + align:start position:0% +tail hydrophobic tail so the hydrophobic + + + align:start position:0% +tail hydrophobic tail so the hydrophobic +tail can stack the oily phase of the + + align:start position:0% +tail can stack the oily phase of the + + + align:start position:0% +tail can stack the oily phase of the +luch this is what you do in cooking you + + align:start position:0% +luch this is what you do in cooking you + + + align:start position:0% +luch this is what you do in cooking you +see how many recipes will ask you to add + + align:start position:0% +see how many recipes will ask you to add + + + align:start position:0% +see how many recipes will ask you to add +a little bit of alcohol and then + + align:start position:0% +a little bit of alcohol and then + + + align:start position:0% +a little bit of alcohol and then +subsequently ask you to to heat it and + + align:start position:0% +subsequently ask you to to heat it and + + + align:start position:0% +subsequently ask you to to heat it and +you say well wait a minute alcohol's + + align:start position:0% +you say well wait a minute alcohol's + + + align:start position:0% +you say well wait a minute alcohol's +going to evaporate what's going on + + align:start position:0% +going to evaporate what's going on + + + align:start position:0% +going to evaporate what's going on +whenever they're asking for alcohol + + align:start position:0% +whenever they're asking for alcohol + + + align:start position:0% +whenever they're asking for alcohol +chances are you're adding something + + align:start position:0% +chances are you're adding something + + + align:start position:0% +chances are you're adding something +fatty to an + + align:start position:0% +fatty to an + + + align:start position:0% +fatty to an +acous uh solution and it doesn't want to + + align:start position:0% +acous uh solution and it doesn't want to + + + align:start position:0% +acous uh solution and it doesn't want to +mix as soon as you add the alcohol co- + + align:start position:0% +mix as soon as you add the alcohol co- + + + align:start position:0% +mix as soon as you add the alcohol co- +solvates alcohol is magical for this a + + align:start position:0% +solvates alcohol is magical for this a + + + align:start position:0% +solvates alcohol is magical for this a +amphipathic character so let's make the + + align:start position:0% +amphipathic character so let's make the + + + align:start position:0% +amphipathic character so let's make the +earthquake the earthquake is with this + + align:start position:0% +earthquake the earthquake is with this + + + align:start position:0% +earthquake the earthquake is with this +we're going to add a little bit of + + align:start position:0% +we're going to add a little bit of + + + align:start position:0% +we're going to add a little bit of +this there it's clear it's it's a it's a + + align:start position:0% +this there it's clear it's it's a it's a + + + align:start position:0% +this there it's clear it's it's a it's a +beautiful green uh green gold color but + + align:start position:0% +beautiful green uh green gold color but + + + align:start position:0% +beautiful green uh green gold color but +it's clear because what's happened now + + align:start position:0% +it's clear because what's happened now + + + align:start position:0% +it's clear because what's happened now +I've put in a third component now I've + + align:start position:0% +I've put in a third component now I've + + + align:start position:0% +I've put in a third component now I've +got water oo alcohol and as I add + + align:start position:0% +got water oo alcohol and as I add + + + align:start position:0% +got water oo alcohol and as I add +alcohol I narrow the Mis ability + + align:start position:0% +alcohol I narrow the Mis ability + + + align:start position:0% +alcohol I narrow the Mis ability +Gap Miss ability Gap Narrows as a result + + align:start position:0% +Gap Miss ability Gap Narrows as a result + + + align:start position:0% +Gap Miss ability Gap Narrows as a result +of that it's + + align:start position:0% +of that it's + + + align:start position:0% +of that it's +fantastic okay Tomy we go back to the uh + + align:start position:0% +fantastic okay Tomy we go back to the uh + + + align:start position:0% +fantastic okay Tomy we go back to the uh +computer graphic please + + align:start position:0% +computer graphic please + + + align:start position:0% +computer graphic please +so this is where we were we were along + + align:start position:0% +so this is where we were we were along + + + align:start position:0% +so this is where we were we were along +This Ti line and I figured the Louch is + + align:start position:0% +This Ti line and I figured the Louch is + + + align:start position:0% +This Ti line and I figured the Louch is +here it's five parts water one part um + + align:start position:0% +here it's five parts water one part um + + + align:start position:0% +here it's five parts water one part um +absen and then away we go this is uh + + align:start position:0% +absen and then away we go this is uh + + + align:start position:0% +absen and then away we go this is uh +this is the late uh 1800s why did absen + + align:start position:0% +this is the late uh 1800s why did absen + + + align:start position:0% +this is the late uh 1800s why did absen +take over in in France because there was + + align:start position:0% +take over in in France because there was + + + align:start position:0% +take over in in France because there was +a a blight that wiped out The Vineyards + + align:start position:0% +a a blight that wiped out The Vineyards + + + align:start position:0% +a a blight that wiped out The Vineyards +and so the price of wine shot up and + + align:start position:0% +and so the price of wine shot up and + + + align:start position:0% +and so the price of wine shot up and +people started turning to absent so you + + align:start position:0% +people started turning to absent so you + + + align:start position:0% +people started turning to absent so you +hear he's making the loose he's pouring + + align:start position:0% +hear he's making the loose he's pouring + + + align:start position:0% +hear he's making the loose he's pouring +water through a SL oted spoon on which + + align:start position:0% +water through a SL oted spoon on which + + + align:start position:0% +water through a SL oted spoon on which +there's a sugar cube and here's a woman + + align:start position:0% +there's a sugar cube and here's a woman + + + align:start position:0% +there's a sugar cube and here's a woman +looking at him saying wow is he ever + + align:start position:0% +looking at him saying wow is he ever + + + align:start position:0% +looking at him saying wow is he ever +cool what a + + align:start position:0% +cool what a + + + align:start position:0% +cool what a +guy hey it's the 1800s all right this is + + align:start position:0% +guy hey it's the 1800s all right this is + + + align:start position:0% +guy hey it's the 1800s all right this is +object of art this is Van + + align:start position:0% +object of art this is Van + + + align:start position:0% +object of art this is Van +go this is Picasso this is the absen + + align:start position:0% +go this is Picasso this is the absen + + + align:start position:0% +go this is Picasso this is the absen +Drinker this is a Picasso after he I + + align:start position:0% +Drinker this is a Picasso after he I + + + align:start position:0% +Drinker this is a Picasso after he I +guess he'd had a lot of Aban this + + align:start position:0% +guess he'd had a lot of Aban this + + + align:start position:0% +guess he'd had a lot of Aban this +is the only thing I can recognize here + + align:start position:0% +is the only thing I can recognize here + + + align:start position:0% +is the only thing I can recognize here +is the slotted spoon with what appears + + align:start position:0% +is the slotted spoon with what appears + + + align:start position:0% +is the slotted spoon with what appears +to be a rather large sugar cube and this + + align:start position:0% +to be a rather large sugar cube and this + + + align:start position:0% +to be a rather large sugar cube and this +is somebody's mind after huge quantities + + align:start position:0% +is somebody's mind after huge quantities + + + align:start position:0% +is somebody's mind after huge quantities +of the thing about it is it had fuon in + + align:start position:0% +of the thing about it is it had fuon in + + + align:start position:0% +of the thing about it is it had fuon in +it which comes from the White Cedar and + + align:start position:0% +it which comes from the White Cedar and + + + align:start position:0% +it which comes from the White Cedar and +what this does is it um antagonizes The + + align:start position:0% +what this does is it um antagonizes The + + + align:start position:0% +what this does is it um antagonizes The +receptors that regulate neuron firing we + + align:start position:0% +receptors that regulate neuron firing we + + + align:start position:0% +receptors that regulate neuron firing we +could think much faster but you know we + + align:start position:0% +could think much faster but you know we + + + align:start position:0% +could think much faster but you know we +we kind of slow ourselves down so it's + + align:start position:0% +we kind of slow ourselves down so it's + + + align:start position:0% +we kind of slow ourselves down so it's +the gamma aminobutyric acid that that + + align:start position:0% +the gamma aminobutyric acid that that + + + align:start position:0% +the gamma aminobutyric acid that that +helps us stay in place and actually + + align:start position:0% +helps us stay in place and actually + + + align:start position:0% +helps us stay in place and actually +epileptics suffer from a lack of + + align:start position:0% +epileptics suffer from a lack of + + + align:start position:0% +epileptics suffer from a lack of +Regulation right but that's a motor + + align:start position:0% +Regulation right but that's a motor + + + align:start position:0% +Regulation right but that's a motor +regulation but in case of you know + + align:start position:0% +regulation but in case of you know + + + align:start position:0% +regulation but in case of you know +mental acuity so this is one of these + + align:start position:0% +mental acuity so this is one of these + + + align:start position:0% +mental acuity so this is one of these +cases where the alcohol tracks with the + + align:start position:0% +cases where the alcohol tracks with the + + + align:start position:0% +cases where the alcohol tracks with the +with the thujone and so instead of + + align:start position:0% +with the thujone and so instead of + + + align:start position:0% +with the thujone and so instead of +making you drunk and and stupid it makes + + align:start position:0% +making you drunk and and stupid it makes + + + align:start position:0% +making you drunk and and stupid it makes +you drunk and very very you know highly + + align:start position:0% +you drunk and very very you know highly + + + align:start position:0% +you drunk and very very you know highly +active and um uh but unfortunately large + + align:start position:0% +active and um uh but unfortunately large + + + align:start position:0% +active and um uh but unfortunately large +quantities of it also had other + + align:start position:0% +quantities of it also had other + + + align:start position:0% +quantities of it also had other +neurological disorders uh if you seen + + align:start position:0% +neurological disorders uh if you seen + + + align:start position:0% +neurological disorders uh if you seen +Mulan Rouge you'll see here this is It's + + align:start position:0% +Mulan Rouge you'll see here this is It's + + + align:start position:0% +Mulan Rouge you'll see here this is It's +All About absen in in that period so + + align:start position:0% +All About absen in in that period so + + + align:start position:0% +All About absen in in that period so +what happened was uh this absen took + + align:start position:0% +what happened was uh this absen took + + + align:start position:0% +what happened was uh this absen took +over I mean people drank huge quantities + + align:start position:0% +over I mean people drank huge quantities + + + align:start position:0% +over I mean people drank huge quantities +of this in place of wine eventually the + + align:start position:0% +of this in place of wine eventually the + + + align:start position:0% +of this in place of wine eventually the +wine uh was restored The Vineyards in + + align:start position:0% +wine uh was restored The Vineyards in + + + align:start position:0% +wine uh was restored The Vineyards in +France were restored by grafting onto + + align:start position:0% +France were restored by grafting onto + + + align:start position:0% +France were restored by grafting onto +American stocks so there are very few + + align:start position:0% +American stocks so there are very few + + + align:start position:0% +American stocks so there are very few +Wines in France that are not produced as + + align:start position:0% +Wines in France that are not produced as + + + align:start position:0% +Wines in France that are not produced as +hybrids on American stock so + + align:start position:0% +hybrids on American stock so + + + align:start position:0% +hybrids on American stock so +occasionally you'll see a bottle of wine + + align:start position:0% +occasionally you'll see a bottle of wine + + + align:start position:0% +occasionally you'll see a bottle of wine +says V Old Vine meaning that that was + + align:start position:0% +says V Old Vine meaning that that was + + + align:start position:0% +says V Old Vine meaning that that was +spared from the felox blight but by and + + align:start position:0% +spared from the felox blight but by and + + + align:start position:0% +spared from the felox blight but by and +large it's on American Vin so French + + align:start position:0% +large it's on American Vin so French + + + align:start position:0% +large it's on American Vin so French +wines are grown on American Roots just + + align:start position:0% +wines are grown on American Roots just + + + align:start position:0% +wines are grown on American Roots just +remember that okay so uh + + align:start position:0% +remember that okay so uh + + + align:start position:0% +remember that okay so uh +the um so now the the wine cooperatives + + align:start position:0% +the um so now the the wine cooperatives + + + align:start position:0% +the um so now the the wine cooperatives +wanted to get people to switch back to + + align:start position:0% +wanted to get people to switch back to + + + align:start position:0% +wanted to get people to switch back to +wine so there was this strange alliance + + align:start position:0% +wine so there was this strange alliance + + + align:start position:0% +wine so there was this strange alliance +between the wine cooperatives and the + + align:start position:0% +between the wine cooperatives and the + + + align:start position:0% +between the wine cooperatives and the +temperance movement to get people to + + align:start position:0% +temperance movement to get people to + + + align:start position:0% +temperance movement to get people to +stop drinking absent and so what + + align:start position:0% +stop drinking absent and so what + + + align:start position:0% +stop drinking absent and so what +happened was there were a number of + + align:start position:0% +happened was there were a number of + + + align:start position:0% +happened was there were a number of +murder trials in which uh somehow it was + + align:start position:0% +murder trials in which uh somehow it was + + + align:start position:0% +murder trials in which uh somehow it was +portrayed that Aban figured prominently + + align:start position:0% +portrayed that Aban figured prominently + + + align:start position:0% +portrayed that Aban figured prominently +and so little by little governments + + align:start position:0% +and so little by little governments + + + align:start position:0% +and so little by little governments +banned it and this is uh uh October 7th + + align:start position:0% +banned it and this is uh uh October 7th + + + align:start position:0% +banned it and this is uh uh October 7th +1910 where ABS santh is being banned in + + align:start position:0% +1910 where ABS santh is being banned in + + + align:start position:0% +1910 where ABS santh is being banned in +Switzerland so here it says gentlemen + + align:start position:0% +Switzerland so here it says gentlemen + + + align:start position:0% +Switzerland so here it says gentlemen +this is the hour and this is the uh uh + + align:start position:0% +this is the hour and this is the uh uh + + + align:start position:0% +this is the hour and this is the uh uh +symbol of absen Aban was known + + align:start position:0% +symbol of absen Aban was known + + + align:start position:0% +symbol of absen Aban was known +affectionately as the green fairy that's + + align:start position:0% +affectionately as the green fairy that's + + + align:start position:0% +affectionately as the green fairy that's +why in in Mulan Rouge you'll see this + + align:start position:0% +why in in Mulan Rouge you'll see this + + + align:start position:0% +why in in Mulan Rouge you'll see this +sort of Tinkerbell type figure uh Nicole + + align:start position:0% +sort of Tinkerbell type figure uh Nicole + + + align:start position:0% +sort of Tinkerbell type figure uh Nicole +Kidman playing this Tinkerbell figure in + + align:start position:0% +Kidman playing this Tinkerbell figure in + + + align:start position:0% +Kidman playing this Tinkerbell figure in +an animation well she's she's the green + + align:start position:0% +an animation well she's she's the green + + + align:start position:0% +an animation well she's she's the green +fairy and she has a wand made of opal + + align:start position:0% +fairy and she has a wand made of opal + + + align:start position:0% +fairy and she has a wand made of opal +because the beverage is opalescent + + align:start position:0% +because the beverage is opalescent + + + align:start position:0% +because the beverage is opalescent +because when when it when it shimmers + + align:start position:0% +because when when it when it shimmers + + + align:start position:0% +because when when it when it shimmers +you have great Radiance and index of + + align:start position:0% +you have great Radiance and index of + + + align:start position:0% +you have great Radiance and index of +refraction that give you that internal + + align:start position:0% +refraction that give you that internal + + + align:start position:0% +refraction that give you that internal +incipient surface so here's the green + + align:start position:0% +incipient surface so here's the green + + + align:start position:0% +incipient surface so here's the green +fairy slain by the temperance movement + + align:start position:0% +fairy slain by the temperance movement + + + align:start position:0% +fairy slain by the temperance movement +and uh and so + + align:start position:0% +and uh and so + + + align:start position:0% +and uh and so +on so uh the last thing I wanted to to + + align:start position:0% +on so uh the last thing I wanted to to + + + align:start position:0% +on so uh the last thing I wanted to to +comment on is how we use the two-phase + + align:start position:0% +comment on is how we use the two-phase + + + align:start position:0% +comment on is how we use the two-phase +regime in + + align:start position:0% +regime in + + + align:start position:0% +regime in +purification so much of what we know + + align:start position:0% +purification so much of what we know + + + align:start position:0% +purification so much of what we know +about uh purification requires that we + + align:start position:0% +about uh purification requires that we + + + align:start position:0% +about uh purification requires that we +go into a two-phase regime because the + + align:start position:0% +go into a two-phase regime because the + + + align:start position:0% +go into a two-phase regime because the +thing that happens in a two-phase regime + + align:start position:0% +thing that happens in a two-phase regime + + + align:start position:0% +thing that happens in a two-phase regime +is two-phase region implies + + align:start position:0% +is two-phase region implies + + + align:start position:0% +is two-phase region implies +compositional + + align:start position:0% +compositional + + + align:start position:0% +compositional +differentiation compositional + + align:start position:0% + + + + align:start position:0% + +differentiation so for example let's + + align:start position:0% +differentiation so for example let's + + + align:start position:0% +differentiation so for example let's +look at here's the phase diagram for one + + align:start position:0% +look at here's the phase diagram for one + + + align:start position:0% +look at here's the phase diagram for one +time I'm going to go to uh liquid Vapor + + align:start position:0% +time I'm going to go to uh liquid Vapor + + + align:start position:0% +time I'm going to go to uh liquid Vapor +so this is the liquid Vapor phase + + align:start position:0% +so this is the liquid Vapor phase + + + align:start position:0% +so this is the liquid Vapor phase +diagram of + + align:start position:0% +diagram of + + + align:start position:0% +diagram of +ethyl alcohol and water so we know that + + align:start position:0% +ethyl alcohol and water so we know that + + + align:start position:0% +ethyl alcohol and water so we know that +water boils at 100° C this is normal + + align:start position:0% +water boils at 100° C this is normal + + + align:start position:0% +water boils at 100° C this is normal +boiling point and ethyl alcohol boils at + + align:start position:0% +boiling point and ethyl alcohol boils at + + + align:start position:0% +boiling point and ethyl alcohol boils at +78.5 degrees + + align:start position:0% +78.5 degrees + + + align:start position:0% +78.5 degrees +C and you know they're both polar + + align:start position:0% +C and you know they're both polar + + + align:start position:0% +C and you know they're both polar +liquids ethyl alcohol is a little bit uh + + align:start position:0% +liquids ethyl alcohol is a little bit uh + + + align:start position:0% +liquids ethyl alcohol is a little bit uh +more elongated than uh water so it's + + align:start position:0% +more elongated than uh water so it's + + + align:start position:0% +more elongated than uh water so it's +very nearly an isomorphous phase diagram + + align:start position:0% +very nearly an isomorphous phase diagram + + + align:start position:0% +very nearly an isomorphous phase diagram +there's a tiny little uh dip + + align:start position:0% +there's a tiny little uh dip + + + align:start position:0% +there's a tiny little uh dip +but by and large it's an isomorphous + + align:start position:0% +but by and large it's an isomorphous + + + align:start position:0% +but by and large it's an isomorphous +phase diagram okay so alcohol and water + + align:start position:0% +phase diagram okay so alcohol and water + + + align:start position:0% +phase diagram okay so alcohol and water +missable in all proportions in the vapor + + align:start position:0% +missable in all proportions in the vapor + + + align:start position:0% +missable in all proportions in the vapor +obviously and this is the liquid so this + + align:start position:0% +obviously and this is the liquid so this + + + align:start position:0% +obviously and this is the liquid so this +is the two-phase Liquid Plus Vapor + + align:start position:0% +is the two-phase Liquid Plus Vapor + + + align:start position:0% +is the two-phase Liquid Plus Vapor +regime so let's say you've got some wine + + align:start position:0% +regime so let's say you've got some wine + + + align:start position:0% +regime so let's say you've got some wine +and it's 10% alcohol so what do you do + + align:start position:0% +and it's 10% alcohol so what do you do + + + align:start position:0% +and it's 10% alcohol so what do you do +you heat the wine up to this two-phase + + align:start position:0% +you heat the wine up to this two-phase + + + align:start position:0% +you heat the wine up to this two-phase +regime and now in the two-phase regime + + align:start position:0% +regime and now in the two-phase regime + + + align:start position:0% +regime and now in the two-phase regime +TI line so what do you note you note + + align:start position:0% +TI line so what do you note you note + + + align:start position:0% +TI line so what do you note you note +that the alcohol content of the vapor is + + align:start position:0% +that the alcohol content of the vapor is + + + align:start position:0% +that the alcohol content of the vapor is +much higher than the alcohol content of + + align:start position:0% +much higher than the alcohol content of + + + align:start position:0% +much higher than the alcohol content of +the liquid so what we can do is we can + + align:start position:0% + + + + align:start position:0% + +condense condense The + + align:start position:0% +condense condense The + + + align:start position:0% +condense condense The +Vapor which puts us down here and now + + align:start position:0% + + + + align:start position:0% + +reheat condense reheat condense and by + + align:start position:0% +reheat condense reheat condense and by + + + align:start position:0% +reheat condense reheat condense and by +doing so we can raise the alcohol + + align:start position:0% +doing so we can raise the alcohol + + + align:start position:0% +doing so we can raise the alcohol +content or in some cases this could be + + align:start position:0% +content or in some cases this could be + + + align:start position:0% +content or in some cases this could be +the way you purify for the liquid it + + align:start position:0% +the way you purify for the liquid it + + + align:start position:0% +the way you purify for the liquid it +doesn't matter I mean you either want + + align:start position:0% +doesn't matter I mean you either want + + + align:start position:0% +doesn't matter I mean you either want +the condensate or you want what was uh + + align:start position:0% +the condensate or you want what was uh + + + align:start position:0% +the condensate or you want what was uh +the base from which you took the + + align:start position:0% +the base from which you took the + + + align:start position:0% +the base from which you took the +condensate and and this is used over and + + align:start position:0% +condensate and and this is used over and + + + align:start position:0% +condensate and and this is used over and +over again it's used in the solid state + + align:start position:0% +over again it's used in the solid state + + + align:start position:0% +over again it's used in the solid state +to purify Metals look up here on the on + + align:start position:0% +to purify Metals look up here on the on + + + align:start position:0% +to purify Metals look up here on the on +the uh slide suppose I have a a solution + + align:start position:0% +the uh slide suppose I have a a solution + + + align:start position:0% +the uh slide suppose I have a a solution +that consists of um uh over here say + + align:start position:0% +that consists of um uh over here say + + + align:start position:0% +that consists of um uh over here say +60% + + align:start position:0% +60% + + + align:start position:0% +60% +60% uh nickel it's all liquid drop down + + align:start position:0% +60% uh nickel it's all liquid drop down + + + align:start position:0% +60% uh nickel it's all liquid drop down +into this two-phase regime the solid + + align:start position:0% +into this two-phase regime the solid + + + align:start position:0% +into this two-phase regime the solid +that comes out has very much less gold + + align:start position:0% +that comes out has very much less gold + + + align:start position:0% +that comes out has very much less gold +in it that means that the liquid behind + + align:start position:0% +in it that means that the liquid behind + + + align:start position:0% +in it that means that the liquid behind +is go the last liquid to solidify is + + align:start position:0% +is go the last liquid to solidify is + + + align:start position:0% +is go the last liquid to solidify is +going to have more gold in it than the + + align:start position:0% +going to have more gold in it than the + + + align:start position:0% +going to have more gold in it than the +bulk that I started with so I can keep + + align:start position:0% +bulk that I started with so I can keep + + + align:start position:0% +bulk that I started with so I can keep +taking that fraction by moving into a + + align:start position:0% +taking that fraction by moving into a + + + align:start position:0% +taking that fraction by moving into a +regime where the composition splits and + + align:start position:0% +regime where the composition splits and + + + align:start position:0% +regime where the composition splits and +I either want the the high fraction or + + align:start position:0% +I either want the the high fraction or + + + align:start position:0% +I either want the the high fraction or +the low fraction so this is the + + align:start position:0% +the low fraction so this is the + + + align:start position:0% +the low fraction so this is the +principle by which in fact the computer + + align:start position:0% +principle by which in fact the computer + + + align:start position:0% +principle by which in fact the computer +grade silicon is made we start with + + align:start position:0% +grade silicon is made we start with + + + align:start position:0% +grade silicon is made we start with +beach sand we upgrade to something + + align:start position:0% +beach sand we upgrade to something + + + align:start position:0% +beach sand we upgrade to something +that's got to be about four or 59 + + align:start position:0% +that's got to be about four or 59 + + + align:start position:0% +that's got to be about four or 59 +silicon for single crystal growth how do + + align:start position:0% +silicon for single crystal growth how do + + + align:start position:0% +silicon for single crystal growth how do +we go from something that's about 98% + + align:start position:0% +we go from something that's about 98% + + + align:start position:0% +we go from something that's about 98% +silicon 2% impurities to such a high + + align:start position:0% +silicon 2% impurities to such a high + + + align:start position:0% +silicon 2% impurities to such a high +degree of uh purification by dropping + + align:start position:0% +degree of uh purification by dropping + + + align:start position:0% +degree of uh purification by dropping +repeatedly into the two-phase regime and + + align:start position:0% +repeatedly into the two-phase regime and + + + align:start position:0% +repeatedly into the two-phase regime and +pulling out the P fraction so the the + + align:start position:0% +pulling out the P fraction so the the + + + align:start position:0% +pulling out the P fraction so the the +key here + + align:start position:0% +key here + + + align:start position:0% +key here +is compositional differentiation which + + align:start position:0% +is compositional differentiation which + + + align:start position:0% +is compositional differentiation which +then then allows you to distill so you + + align:start position:0% +then then allows you to distill so you + + + align:start position:0% +then then allows you to distill so you +start with 10% you end up 40% you go + + align:start position:0% +start with 10% you end up 40% you go + + + align:start position:0% +start with 10% you end up 40% you go +from wine you end up with brandy or + + align:start position:0% +from wine you end up with brandy or + + + align:start position:0% +from wine you end up with brandy or +cognac so there it is it's all back to + + align:start position:0% +cognac so there it is it's all back to + + + align:start position:0% +cognac so there it is it's all back to +chemistry chemistry chemistry okay we'll + + align:start position:0% +chemistry chemistry chemistry okay we'll + + + align:start position:0% +chemistry chemistry chemistry okay we'll +see you on Wednesday \ No newline at end of file diff --git a/n-NpJQgSLrk.txt b/n-NpJQgSLrk.txt new file mode 100644 index 0000000000000000000000000000000000000000..582e68d7c259bdefc3bfaeda2783b04f8e6271c8 --- /dev/null +++ b/n-NpJQgSLrk.txt @@ -0,0 +1,3407 @@ +The following +content is provided + +under a Creative +Commons license. + +Your support will help MIT +OpenCourseWare continue + +to offer high quality +educational resources for free. + +To make a donation or to +view additional materials + +from hundreds of MIT courses, +visit MIT OpenCourseWare + +at ocw.mit.edu. + +PROFESSOR: All right, +so now today, the topic + +we are going to discuss will +be the ON and OFF channels + +in the retina. + +I will provide you +with a brief overview + +again of what we have +covered before about this, + +and then will go on and +look at this in some depth. + +Now before I start +on that, let me just + +very briefly mention again +that the syllabus-- which + +all of you I presume have. + +If any of you doesn't have +a syllabus-- any one of you + +doesn't have a syllabus, +we can provide one for you. + +What I would like to +encourage all of your + +again is that you do this +so-called preparatory + +reading that appears +for each session, which + +will make it easier +for you to follow, + +and consequently, also +memorize the basic facts + +that we are going +to be dealing with. + +Alright, so therefore let me get +started with the so-called ON + +and OFF channels. + +And what I would like +to do first of all + +is to tell you what are the +major questions we are going + +to pose in dealing with +this very-- to me at least-- + +very interesting question +of the ON and OFF channels. + +The first prime question +you're going to ask + +is why did the ON and +OFF channels evolve? + +What is their function? + +As I've already +indicated before, + +it is rather complicated to +have created these two channels, + +and therefore there +must have been + +a great deal of evolutionary +pressures to accomplish this. + +So that's the prime +question we're going to ask. + +Now more specifically +we're going + +to ask how the +rods and the cones + +are involved in the creation +of the ON and OFF channels. + +And then you're going to +ask how do the ON and OFF + +channels contribute +to the center + +and surround organization +of retinal ganglion cells, + +because this has been a big +issue among many investigators + +over the past 20 or so years. + +Then you're going to ask what +role do these channels play + +in giving rise to the +transforms that we had discussed + +the last time in visual cortex. + +And lastly we're +going to ask what + +are the consequences of +blocking the ON channel + +on neuronal activity +and on perception. + +And this last +question then will be + +successful in answering +several of the questions + +that we pose as to why we have +these curious arrangement of ON + +and OFF channels in the retina. + +All right. + +So now let me first of all talk +about the neuronal responses-- + +sorry-- of the ON and OFF +retinal ganglion cells. + +First of all, if you +remember, I told you + +that back in the 19th +century, Keffer Hartline + +was the first to record +from single neurons + +by dissecting single +fires in the optic nerve. + +And then what he did-- he +shone light into the eye. + +And then subsequently-- +especially when + +I talked the last time +about Hubel and Wiesel-- + +what was done is to +use reflected light. + +And most currently we +using reflected light + +by presenting images on +a computer monitor facing + +the animal or the +human we are studying. + +Now when Keffer +Hartline did this + +by shining light +into the eye, he + +noticed that there are some +says which are called ON cells, + +some cells that are OFF +cells, and some cells which + +are both ON and OFF. + +Now his idea at that time +was, using that method, + +that ON cells discharge +when a stimulus came on + +in the visual +field, and OFF cells + +signaled their termination. + +That was his idea, +and that's why + +I call them ON and OFF cells. + +So subsequently, especially when +reflected the light was used, + +a different view had +emerged as to what + +might be the reason for +having these kinds of cells. + +And this was further enhanced +by the beautiful findings + +of Kuffler, when he +noticed that there + +was center-surround +organization in these cells + +at the so-called ON, +OFF, and ON/OFF cells + +responded vigorously +when a light was + +shown into the center, +but responded less + +when the light shown +into the surround. + +So then people began to do +all kinds of experiments + +to try to study this in +further detail, and one of them + +was to use reflected light, +either by using a projector + +or by using a color monitor. + +And when they did that-- I'm +going to show this to you + +schematically-- they +found that if you + +had a certain lit background +like we have here, + +you could present the +stimulus either by virtue + +of light increment or by +virtue of light decrement. + +And as I had mentioned +to you before, + +the visual system +is dramatically + +different from the other +senses that we have in + +that we need to be able to see +dark stimuli in a background, + +like letters on a page, as well +as light incremental stimuli. + +And so this idea then, +if it's selected that way + +schematically, looks like this. + +An ON cell will fire +vigorously when a bright spot + +appears in the center, and +will not fire to a dark spot. + +If anything, it'll be +slightly inhibited. + +OK? + +By contrast, when you look at +an OFF cell, you get inverse. + +It fires vigorously. + +If you would, it gets +excited by a dark spot. + +It gets excited by the +detriment in light illumination. + +Now if you did the same thing +using a much larger spot + +of light-- that is shown +here-- what you see here + +is that the +center-surround antagonism + +that we talked +about fully applies + +to this kind of stimulation +conditions as well. + +Use a large spot, bright +spot, or dark spot + +and you see that +the over responses + +of the cells-- the responses +are much more limited than when + +you confine the simulation +to the center, only + +further emphasizing +this important fact + +about center-surround +antagonism-- + +this incredible increasing +complexity of the organization + +of neurons that you see +already in the retina. + +OK, so now we are +going to next look + +at the anatomy of the ON +and OFF ganglion cells. + +And as we look at these various +ways of studying the ON and OFF + +channels, we are gradually +going to understand + +what these two systems +are really for. + +So the first thing is to use +this method that I had also + +already described, namely that +you can record intracellularly + +from a cell, understand +its functional responses, + +and then you can inject +a label, and then + +you can process +that anatomically + +to see what it looks like. + +So when this was done, a +very interesting new finding + +had emerged, which +is depicted here. + +Here we have the +photoreceptors-- + +just the tail end of +them, if you will-- that + +connect to the bipolar cells. + +Two bipolar cells are shown. + +And then they project into the +inner plexiform layer, which + +we often just refer +to as IPL, which + +is subdivided into +two parts-- A and B. + +And it was shown that +the majority of cells + +arborize in either one or the +other of these two sublamina + +in the inner plexiform layer. + +But there were also some +cells, which is not shown here, + +that had arborization +in both of these lamina, + +and that's to +anticipate actually + +the property of those cells, +which are called the ON/OFF + +cells. + +Now furthermore, it was found-- +because these cells were + +labeled after recording-- +that the cells that arborized + +in subliminal A, or the +inner plexiform layer, + +were so-called OFF cells, +and those that arborized + +in subliminal B, +like this one here, + +and this one here, and this +one here, were ON cells. + +OK? + +So there was a distinct +spatial segregation + +into the lamina of those +retinal ganglion cells that + +were ON and OFF, and +also furthermore, + +those that were +ON/OFF because they + +had arborization +in both of them. + +So that was the basic finding. + +Now when that was +discovered, people + +went on and asked +the question, what + +is the spacial +arrangement of these cells + +on the retinal +surface, if you will. + +And so experiments were done +in which cells were labeled, + +in most cases with +the Golgi stain, + +and then the retina was looked +at head on with a microscope. + +Now the interesting thing +about a microscope is, + +which all of you +I'm sure know, is + +that the higher +the magnification + +that you use, the shorter +the focus of the microscope. + +And in fact, what +you can do here + +is when you look +at his head I like + +that, if you can focus either +in sublamina A or sublamina B, + +and if you do that, since +we had gotten these results, + +you know that whatever focuses +into sublamina A would be OFF + +cells, and whatever +comes into focus + +and the [INAUDIBLE] is +coming to focus in B, + +would be the ON cells. + +So then what was +done by a fellow + +called Heinz Wesley is +he asked a question, what + +is the spacial +arrangement of these two? + +Do they respect +each other, or what? + +And so when he did that, +here is a good example + +of what that looks like. + +Here we have labeled both the +ON and OFF cells using the two + +depth of [INAUDIBLE], +and you can + +see they're kind +of helter skelter. + +Then if he focus deeper, he +focus only in the ON cells. + +It looks like a they're +very, very nicely arranged, + +and that's also true +for the OFF cells. + +And they respect each other. + +Looking at the dendritic +arbors, there's + +a little overlap among +the dendrites themselves + +of the cells. + +So what's this then said is that +the ON cells respect each other + +but don't seem to give a +damn about the OFF cells. + +And the reverse applied +to the OFF cells. + +OK? + +So as if there were two +independent entities. + +So that was a very +interesting finding. + +And so that was one of +the initial cues saying + +that these ON and OFF +cells do different things, + +and each is a devoted +entity to what it does. + +All right so now to understand +this even better, let's go back + +and take a brief overview +of the retinal connections + +so we can understand how +these systems came about. + +And the first thing to do is +to talk about the photoreceptor + +basics. + +And I told you many times-- +by now I'm sure all of you + +know that already-- that all +photoreceptors hyperpolarize + +to light. + +Then I also told you when +photoreceptors depolarize-- + +that's when they release +their neurotransmitter, which + +is glutamate. + +And that glutamate acts on +both the horizontal cells + +and the bipolar cells. + +And then furthermore, just +to look in the details-- + +this you don't need to remember +exactly in these words-- photon + +absorption by the photopigment +results in isomerization + +of the chromophore from +11-cis to all-trans. + +To all-trans this causes +hyperpolarization, thereby + +reducing +neurotransmitter release. + +But what you do need to +remember is the next step, + +which says the same thing +in much simpler words. + +It says that the two +classes of bipolars, + +the ON and the OFF, synaptic +junction of the OFF bipolars + +is sign conserving, and +that of the ON bipolars + +is sign inverting. + +And so as I've told you the +last time, as you hyperpolarize + +and depolarize +the photoreceptor, + +an OFF bipolar cell does +the same thing like this, + +but the ON bipolar +does the opposite, OK? + +So you created a +two-ended system-- + +a double-ended system, if you +will-- from a single-ended one + +that you have in +the photoreceptors. + +Now, yet another fact that +is important to remember + +is that the ON bipolar +cell receptor is mGluR6. + +That is a specific molecule +that exists in most animals, + +only in the retina, created +anew in the course of evolution, + +indicating what +considerable pressure there + +had to be able to +have an ON system. + +And lastly I should add here +also that the OFF bipolar + +receptors are mGlueR1 and 2 +and they follow, pretty much, + +the way the +photoreceptors respond, + +which means that +their activation leads + +to the opening of channels, +causing depolarization. + +And of course you all know +that-- I should restate maybe + +once more-- that when neurons +in the retina that had greater + +potentials, when +they depolarize, + +neurotransmitters released. + +When they hyperpolarize, +they do not release them. + +In anything, they +stop releasing them. + +OK. + +So now let's look at this wiring +again in more graphic detail. + +Here we have a cone. + +And the fact is that +in central retina, + +each cone connects with at +least two bipolar cells. + +So in other words, in the +retina there are many, many more + +bipolars than there +are photoreceptors, + +which is amazing if you +think about the numbers. + +I don't know if you +remember the numbers. + +I told you there are more than +50 million cones, and maybe + +150 million rods, in the retina. + +So the retina is an +unbelievably complex structure + +with millions and millions +and millions of cells. + +All right. + +So what happens then-- you +create these ON and OFF bipolar + +cells. + +The OFF ones, by virtue are +sign conserving synapse. + +The OFF, by virtue, are +sign conserving synapse. + +And they connect with two basic +classes of ganglion cells-- + +the ON and the OFF. + +So the ON and OFF +signals, in large part, + +then are sent +separately, especially + +to the [INAUDIBLE] nucleus. + +But let's not forget +that they also + +have the so-called ON/OFF cells. + +And many of them actually end +up projecting the colliculus, + +as we'll talk about later on. + +So this is a very basic wiring. + +They can then add here, +as I've already said. + +This is sign inverting synapse. + +This is sign-conserving +sign conserving synapse. + +And then we can add +the fact that we + +have horizontal cells that +collect signals going sideways + +on the retinal surface, +thereby creating-- + +hypothetically speaking, at +least-- the surround effect, + +although that we will look at +in just a minute in more detail + +because some people had +proposed-- many hypotheses had + +emerged why we have +ON and OFF channels-- + +and a lot of the +hypotheses was to create + +this famous +center-surround antagonism + +that you see in the +retinal ganglion cells. + +I'll have a model +for that in a minute. + +OK, so here we have +the ON and OFF systems. + +And again I want +to point out to you + +that they terminate in different +sublamina, the inner plexiform + +layer-- the ON in sublamina +B and the OFF in sublamina A, + +whereas the ON/OFF system +looks something like this. + +It has dendritic arbors. + +They are ON/OFF ganglion +cell in both layers, + +and connects to both the +ON and the OFF like that. + +So that's how you +create these three + +types of cells at the +very simple level. + +Now the issue that I +just to referred to + +is how is this surround +mechanism created. + +One hypothesis is +that it's created + +by virtue of the +horizontal cells + +predominantly, as shown +in this figure, which + +is pretty much what +you had seen before. + +So the surround is created by +the horizontal cell network. + +An alternative hypothesis +that was for a while popular + +was that actually the reason +we have ON or OFF channels + +is to create the surround +antagonism in retinal ganglion + +cells by using this kind +of wiring arrangement. + +I'm not going to go +into details about this + +because to anticipate +what I'm going + +to tell you is that this model +does not seem to be correct, + +and that of course +is often the case. + +We have many, many +different models + +and then one of +our tasks is to try + +to figure out which +one is correct. + +And you know what +often happens is + +that if three models +are correct, well + +there's a fourth one you +didn't even think about. + +So that sometimes +happens, and especially + +when you study the brain. + +All right. + +So now we are going to move on. + +This is, unless you had read +the preparatory material, + +is something that +may puzzle you-- + +the effects of APB +on the responses + +of neurons in the visual system. + +So now I'm going to ask you guys +as to how many of you actually + +know what APB is. + +Oh, I see all +these hands raised. + +Oh my goodness. + +All right. + +So nobody knows what the APB is. + +That's good. + +So that way you are going to +learn something brand new. + +But if you get a chance and +read the preparatory material, + +then it will be easier for to +remember these many, many facts + +that I'm going to try to impart +on you with each lecture. + +All right, so APB. + +APB stands for an +artificial molecule called + +2-amino-4-phosphonobutyric acid. + +And to show that to you in +some detail, it is shown here-- + +2-amino-4-phosphonobuterate . + +Butyrate-- "ate," as you +know, stands for acid. + +OK? + +So this molecule, as I +mentioned to you before, + +was invented, if you +will, by Watkins and Evans + +in England, who are +molecular biologists. + +And their game, as I mentioned, +is to create new molecules-- + +and many of which are either +analogs or antagonists + +of neurotransmitters. + +Now this is a glutamate +neurotransmitter + +that is discharged by many, +many cells in the brain, + +including your photoreceptors. + +So this is a variant of that. + +Now once this molecule +was invented, or created, + +I should say +perhaps, people began + +to ask the question, well +what is this variant? + +What can they do for us? + +And that was the basic +game they all played. + +You create molecule after +molecule after molecule, + +and then you test them to +see whether they can tell you + +something useful in +studying the brain. + +And it turns out that there's-- +I've mentioned before also-- + +most of those molecules you +can throw into the waste paper + +basket. + +But the few of them come out +and become very, very useful. + +And this one here-- +that's the reason + +I'm mentioning it to +you-- this APB turned out + +to be a magic bullet. + +First of all-- you +should remember this-- + +that this a +neurotransmitter analog. + +So what happens is in a +way it acts like glutamate, + +but it acts really specifically +on the neurotransmitter + +sites of the ON bipolar cells. + +And what it does-- it +fills the receptor site, + +which then makes those +neurons insensitive + +to subsequent light stimulation. + +All right? + +So this then is a +remarkable molecule. + +And consequently, people began +to do all sorts of experiments. + +And it was discovered that +when this substance was applied + +to the retina, indeed shining +light into the receptor + +fields of cells failed +to elicit a response. + +But by contrast, when +as part of dark stimulus + +was present in the +receptor field, + +the cells continued to fire. + +So that was a basic finding, +and so a method was developed + +to study this in the monkey. + +And let me show you +what the method is + +so you can get a +sense of what it's + +like to do +experiments like this. + +So the method was +to put two tubes + +into the eye of an anesthetized, +paralyzed animal, through one + +of which you could +infuse a substance, + +and through the other which +the substance could exit. + +Because if there were no exiting +and you fuse something in here, + +the eye would swell +up, so to speak, + +and it would kill +the cells in the eye. + +So you got to circulate it. + +So what you have to do also +is to take the vitreous humor + +and make sure that-- you know +that's a jelly-like substance-- + +to make it so that it was fluid +enough to come out of this tube + +here, as well. + +So then you could present to +the eye either a solution that + +had no effect on +anything, because you made + +that solution with enough +molecular substances + +similar to what's in +the vitreous already. + +OK? + +And then what you +could do is you + +could switch over using +this same substance + +and add a little bit of APB. + +Now APB is a very +powerful substance + +so you need only small amounts +of it to have an effect. + +And then what you +did is you recorded + +from either the lateral +geniculate nucleus, + +in this case, or from +the optic nerve fibers, + +or from the visual cortex. + +And so now you have +this magic bullet, + +and first, however, you want +to determine, is it true. + +What has been found originally +in the mutt puppy-- is it also + +true in the monkey? + +If you inject this APB +into the eye of a monkey, + +do you really stop the +responses of ON-center cells + +to view light +visual stimulation, + +light incremental stimulation. + +And the answer is lucky +B-- because otherwise I + +wouldn't be telling +you this, of course-- + +is that the answer is yes. + +So here is an example +of taking a response. + +These are cumulative +histograms, OK? + +You've turned the light +on, and then turned it off. + +And you can see here's an +ON-center cell responds + +vigorously under +normal conditions. + +You put APB into the eye, +the cell stops responding. + +And then when the animal +recovers from this, + +you wash it out, so to speak, +then the response returns. + +By contrast, we +do same experiment + +in an OFF-center cell, +shown on the right. + +You see that the cell +continues to respond + +when you put APB into the eye. + +So this is indeed +a magic bullet, + +which selectively +blocks the ON system, + +and has no significant +effect on the OFF system. + +So this then opened +the gates to study + +what happens when you do +these kinds of experiments-- + +in this case, in +monkeys-- to determine + +what might be the function +of these two systems. + +And so this then enabled one +to test the various hypotheses, + +which I had mentioned +to you briefly before. + +The first hypothesis +you can ask, + +is it true-- as that model +I've shown you the right-- + +that it is interaction +between the ON or OFF systems + +that gives rise to the +center-surround antagonism + +of cells in the retina. + +That's one thing you could test. + +So to assess that, +let me show you + +what the experimental +procedure is. + +What you do here-- here is +a receptive field of a cell. + +And in this case, this cell-- +the recording is taking place + +in the geniculate-- and +this particular cell + +is one that is color selective. + +It responds best to +a small red spot. + +And if you hit the surround +with a different color, + +the cell is inhibited. + +So the way this is +then done is you + +shine the light on +the center, then + +you shine the light +on the surround, + +and then you're +in the OFF cycle-- + +you just hit the surround alone. + +So this then shown to +you here over time. + +Here's a center stimulation. + +Turn it on. + +Then you hit the surround. + +Then you turn it off. + +So because-- and +the center stays on, + +and during the OFF cycle, +you hit the surround. + +So this shows the +exact manner in which + +you turn these on and off. + +All right. + +So now the big question is, +how do ON- and OFF-center cells + +respond to this +stimulus arrangement. + +So say you have an ON cell, +which would discharge to this. + +Then the response +should decrease + +because of the +surround inhibition. + +And you'll see the +normal response. + +And the question +now-- what's going + +to happen if you put in the APB? + +Well there are a number +of possibilities. + +One is that nothing's +going to happen. + +That's unlikely because +I already showed you + +that APB blocks the ON +response of the center. + +The other possibility +is that you + +lose the center-surround +antagonism, which + +would prove that the ON and OFF +systems play a significant role + +in creating +center-surround antagonism. + +All right. + +So those are some of +the possibilities. + +And of course a +third possibility + +is that the OFF cells also +lose their surround antagonism, + +although their responses to +the center are unaffected. + +So let's take a look at that. + +And here are the data +under normal conditions. + +This again is the stimulation +arrangement lined up, + +but you can see here +there's a huge response when + +you hit the center +with a red spot, + +and then when you hit +the surround there's + +a huge inhibition. + +When you remove that, +the response returns. + +And then during the +OFF cycle, there's + +some spontaneous activity, but +the surround activation even + +stops that. + +So there's very strong +center-surround antagonism. + +All right. + +So now I want you to +guess for a minute. + +What do you think +is going to happen + +when we inject APB into the eye? + +Think about it for a +minute and I'll tell you. + +I listed some of +the alternatives, + +and you can have a +hypothesis of your own + +of what you think might happen. + +All right let me show you +what really happened, OK? + +When this happened, actually, +the experimenter thought, + +my god, we lost a cell +while we were recording. + +But then, subsequently when +the APB was washed out, + +you got the same +response as before. + +And so the cell wasn't lost, +but the APB was so effective + +that it stopped the +response of the cell + +completely, both of the +center and to the surround. + +And now let's ask the question, +what happens when you do this, + +not to an ON-center cell, +but an OFF-center cell. + +Think about it +again for a minute + +and ask what do you +think would happen then. + +OK, so here it is. + +Here is an OFF-center +ganglion cell. + +And it shows here, using the +same stimulus conditions, that + +in this case, because +there's an OFF + +cell, adding the +surround decreases + +the degree of inhibition +turning OFF cycle. + +And here again the same +thing is happening. + +But the same thing happens +under both normal conditions + +and after APB had been injected. + +So what this experiment then +shows-- and of course one + +does this with +many, many cells-- + +is to prove that the +hypothesis, that the ON and OFF + +systems play a significant role +in center-surround antagonism, + +is wrong. + +And because of that, that +hypothesis has been eliminated. + +All right. + +So then we can move on +and ask the next question. + +I mean, let me first +draw this up again here. + +All right. + +Here we have the +photoreceptors-- + +the cone photoreceptors-- the +horizontal cells, and the ON + +and OFF cells. + +So this alternative hypothesis, +that the surround inhibition + +is due to horizontal +cells, therefore, + +has gained much +greater acceptance. + +OK. + +So now we are going +to move upstairs + +and we're going to go to area V1 +where we can ask the question, + +well what were the transforms +that we had seen in V1. + +I presume all of you remember. + +What are the three major +transforms we talked about? + +Who remembers? + +Come on. + +Sure you remember that, don't +you-- that we have cells-- + +most of the cells are +orientation specific, right? + +Most of the cells are +direction selective. + +And most of the +cells are selective + +for spatial frequency. + +So those are three of +the major transforms. + +The other two we talked about is +a convergence of the ON and OFF + +channels onto single +cells in the cortex. + +And the other was that +there was a binocular input + +to many of the cells. + +So those were the +major transforms + +we talked about the last time. + +And again I want to emphasize +the importance of this + +by telling you that +Hubel received the Nobel + +Prize for those discoveries +of how V1 operates. + +OK? + +And of course I mentioned +before that Keffer Hartline, + +when he discovered the ON +and OFF systems using light + +that he shown into the eye-- +he called them the ON and OFF + +cells-- he received the +Nobel Prize as well. + +So those are truly, truly +major, major discoveries + +and have triggered hundreds +and hundreds of experiments + +trying to understand better. + +And certainly one of the +questions that was raised + +is how does orientation, +and direction cell activity, + +and special frequencies +activity, for that matter, + +arise in area of V1. + +And one prominent +hypotheses was indeed + +that the reason we have +ON and OFF channels + +is to create these transforms +in the visual cortex. + +So what we can then +do, now that one + +has this magic +bullet of the APB, + +that one can record +from a cortical cell. + +See how it responds when +you inject APB in contrast + +to before you injected +it and after injected it. + +So that's the big question +you're going to ask next. + +All right. + +So here is an example of what +of cortical cell's response + +looks like using this kind of +histogram when a bar of light, + +in this case, is moved +across the receptive field. + +Now this is a complex cell. + +And you can see it gives +a vigorous response when + +the light edge goes +across, and then it + +gives a vigorous response when +the dark edge goes across. + +I'm showing this only for +one direction of motion. + +So that is a natural response. + +So now the question +comes up, what + +happens when you inject +APB into the eye. + +A number of possibilities exist. + +The most basic one I think +most of you would buy + +is that the light edge response +is produced predominantly + +by the ON channel, +and the dark edge + +response by the OFF channel. + +And if that is the +case, then this response + +should be eliminated by +blocking it with APB in the eye. + +And if you do that, that's +exactly what happens. + +You can see here under +normal conditions, + +you get a vigorous response +for both light and dark edges. + +After APB, only a dark +edge response remains. + +So this then established +that these responses + +to the different edges-- the +light edges and dark edges-- + +are a product of the input from +the retina to the geniculate, + +and then to the cortex from the +ON and the OFF channels, which + +then converge in +many cortical cells, + +as is the case in this +particular cortical cell. + +So that then establishes +this very basic fact. + +Now the next +question we can ask-- + +what about those transforms +you talked about? + +Let's first of all +look at the transform + +of direction selectivity. + +So we can take a cell +that is, in this case, + +directionally biased. + +And you can see what +the response is before + +and after APB is injected. + +And what you see +here-- we move the bar + +across in one direction, and +then we move the bar back + +across the opposite direction. + +So the first half shows +a downward movement-- + +the second half, +the upward movement. + +Now what you see here +that the cell responds + +is much more vigorous. + +It's not 100% +direction selective. + +I showed you some of +those the last time. + +This one is a bias-- +about a four to one bias-- + +much more response to +the downward movement + +than the upward movement. + +But the cell responds both +the light and the dark edge + +in both directions, +and it lines up + +with the temporal +arrangement here, + +proving indeed that +this is a complex cell. + +Now then when you +inject APB into the eye, + +look what happens. + +You eliminate the light +edge response here and here, + +but the cell is still +directionally biased. + +So direction specificity +was maintained. + +And when this was +studied in many, + +many, many cells-- +even cells that + +were 100% direction specific-- +blocking the ON channel + +did not eliminate +directionality in the cortex. + +So that then indicates that +the ON and OFF channels did not + +arise to bring about direction +selectivity in the cortex. + +And so that brings us +to the second transform, + +which is orientation +specificity. + +So we can do that next. + +And here we have an example +using a very similar procedure. + +Again, a complex cell +when the APB is injected. + +The light edge +response disappears. + +You move the bar across +the different orientations + +and this is the orientation +specificity you get. + +Now this is calculated here on +the basis of only the dark edge + +response because you +want to keep it the same + +as you're going to do here. + +Since the light edge +response is eliminated, + +you can see that the cells +orientation specificity is also + +unaffected, meaning +that the orientation + +specificity of +the cortical cells + +is not due to the interaction +between the ON and OFF channel. + +Similar experiments were also +done with spatial frequency + +selectivity, and again, +no effect was found. + +So this then led +to the conclusion + +that the ON and OFF +channels did not + +arise for the purpose of +creating the transforms that we + +had denoted in our last +lecture about single cells + +in the visual cortex. + +All right. + +So now what we can do +is here-- we can come up + +with a silly model, just +to make it memorable, + +which is to say +that the ON and OFF + +channels flow into the cortex. + +And these attributes we talked +about-- orientation, direction, + +and spacial frequencies +selectivity-- + +are produced by +cortical filters. + +What you have in +the cortex are all + +kinds of inhibitory interneurons +and the interactions + +among many, many neurons. + +And that kind of +activity that you + +get there is the one that +produces these attributes, + +not the interaction between +the ON and OFF channels + +that flow into +the visual cortex. + +All right. + +So now the next +question we can ask, + +or what happens on APB under +photopic viewing conditions. + +We'll talk about scotopic, +as well as photopic, vision. + +To do this, and to answer how it +affects our visual capacities, + +what we do is to turn to +behavioral experiments. + +In behavioral experiments, +what you can do + +is you can present +various kinds of stimuli. + +You can train a +monkey-- in this case, + +with monkeys-- to see how +well they perceive a stimulus, + +and ask them to make an eye +movement to that stimulus. + +So when you do +this-- testing that + +hypothesis I've shown you +earlier about light increment + +and light decrement-- +what we can do + +is to train a monkey +to first fixate. + +And then after the +monkey fixated, + +you can present either +a light incremental spot + +or a light decremental spot. + +The monkey's task is to make +a saccade to that target. + +And of course, those +spots will appear randomly + +in several different +locations in each trial, + +so the monkey doesn't know +where he's going to appear. + +And if he makes a +correct saccade to it, + +he will get a drop of +apple juice for a reward. + +So that is the procedure. + +And so now the question +then comes up-- + +how well does the +monkey do in being + +able to detect light +increment and light decrement? + +So if you do that, luckily +one gets a very clear cut + +and dramatic result. + +Here is the section +that I will show + +you data for light +increment, and here + +is a section showing +data for light decrement. + +So here is an example. + +What you measure +here are two things-- + +you measure the monkey's +percent correct performance, + +and you measure what the +saccadic latencies are + +to make a saccade to the target. + +So it shows here that +under normal conditions, + +the monkey's +performances is over 90%, + +and that he has a +very nice distribution + +of saccadic latencies +with a mean of about two + +in 53 milliseconds. + +Then when you apply APB +to the eye, what happens + +is that the monkey's +performance drops dramatically. + +He is just a little +bit above probability, + +and his latencies are very, +very late-- very, very, + +very long-- 406 milliseconds. + +So in other words, +the monkey can barely + +perceive a light +incremental stimulus + +by virtue of having blocked +the ON channel in the retina + +by APB. + +Now if you do the +same experiment + +with light decrement, +what you see here + +is the monkey's +performance remains + +normal-- about 95% correct. + +And the latency +distribution is also + +about the same-- two in 49, +versus two in 51 milliseconds. + +So that then says that +indeed the ability + +to detect light +incremental stimuli + +has been devastated by +the injection of APB, + +and therefore raised the +idea that the ON and OFF + +channels are for the purpose +of quickly and efficiently + +detecting light increment, +as well as light decrement. + +So that then was +the basic finding + +that was obtained with this +behavioral experiment studying + +the monkey's +performance on being + +able to process visual stimuli. + +Now we are going to get +a bit more complicated, + +because what we +talked about so far + +was under photopic +conditions, meaning + +when your cones were +fully functional. + +So the question is what happens +under scotopic conditions, + +meaning what happens +when you're dark adapted. + +Now we have talked +about this before. + +It was pointed out, +initially by Schultze, + +that we have two basic classes +of photoreceptors-- the rods + +and the cones-- and that the +rods are for night vision. + +So now the question is, what +happens under night vision + +conditions. + +And when this was found-- this +was truly, truly baffling. + +And I'm going to +show you the data. + +It showed here under +light adapted conditions + +with the same kind of +data-- but shown only + +as histograms in this +case-- the monkey + +does equally well +for light and dark. + +And when you apply +APB, the monkey + +has difficulty seeing the +light incremental stimulus, + +but has little loss in the +light decremental stimulus. + +OK? + +But when you do the same thing +under dark adapted conditions, + +when only the rods +are operative, + +a curious thing happens. + +The monkey doesn't see either +light increment or light + +decrement. + +In other words, and the +way to put it shortly, + +is to say that the monkey +has become night blind. + +Now there are, among humans, a +small population of individuals + +individuals who are +night blind, and what's + +the situation with them? + +It's called "night +blind" because they just + +see very poorly at night. + +And, in fact, when +that is known, + +they only get a special kind +of driver's license-- one + +saying you can drive +in the daytime, + +but you can't drive at night. + +So now we have a +monkey here with APB + +injected-- that +he's night blind. + +And also you see the same data +reflected in the latencies, + +just like before. + +And it shows that the +monkey is devastated + +both for light increment +and light decrement + +by having a tremendous +increase-- more + +than a tripling of +latencies for the few trials + +that he did carry out correctly. + +So now this being the case, +it raises a big question-- + +and I'm sorry that things +are getting so complicated, + +but the brain is +complicated-- as + +to just what is the nature +and arrangement of the rods + +in the retina, and +how does that relate + +to the arrangement of the cones? + +OK? + +So that brings me to +an interesting point. + +Again, as so often +happens, whenever + +you're confronted +with a puzzle, you + +have all kinds of hypotheses. + +And then luckily if you do +this instead of experiments, + +you come up with the +right kinds of tools. + +You can eliminate most of them +and come up with the right one. + +Now, so we can +ask, first of all, + +without talking +about APB at all now, + +simply ask a general +question-- what + +happens to the receptive fields, +or retinal ganglion cells, + +under dark adapted conditions? + +And what happens is that the +receptive fields become larger. + +Now this initially-- discovered +by Barlow in England-- + +was negated by the other +individuals saying, + +you just got scattering of +light-- that's why it's larger. + +So it was kind of +dismissed, but in the end + +it turned that he was +right, as you shall see. + +The other thing that happened +is that the color selectivity + +response disappears in the +retinal ganglion cells. + +And not only that, but it +disappears behaviorally. + +So when you have a +red rose, and you + +look at a red rose at night when +only your rods are functional, + +it looks like a black rose. + +The rods cannot process color. + +OK? + +They can only process light +increment and decrement. + +OK, again just to reiterate-- +the receptive fields + +become larger. + +OK. + +So the big question is +what on earth is happening, + +what kind of wiring +is taking place, + +or what kind of +connections are created + +to create these two things. + +Now the second one is the +one that's the big puzzle. + +The first one we can +understand because it's + +been shown that rods +are only one type + +and that they don't +carry color information. + +Now to study this further, way +back when in the 1870s-- 1880s, + +Cajal did the large number +of experiments of this sort. + +If you remember, I told you +that Cajal played a central role + +in using the Golgi stain, and +that he and Golgi received + +the Nobel Prize in 1906 +for their major discoveries + +about this. + +So now he argued that +the way this happens + +is that rods and the +cones connect differently + +with the ganglion cells. + +And so here is a +picture of Cajal. + +He spent most of +his life like this, + +looking through a +microscope, endlessly looking + +at brain slices, and studying +the individual cells-- + +the shapes and drew them, +as you can see his pencil. + +He is in the middle drawing, +actually, a cell there. + +And so he speculated +about this a great deal. + +And he was just a +remarkable person. + +And he had written +an autobiography. + +And the way he speaks in this-- +translated from Spanish-- + +but he has an incredibly +colorful way of talking-- + +"had," I guess I should say. + +And I want to +quote some of this, + +because I think you'll find +it interesting and amusing. + +So he said, "Since this +impression received by the rods + +is different from that +taken by the cone, + +it is necessary from +every point of view + +that each of these +specific impressions + +should be conveyed through the +retina by a separate channel." + +The translation leaves a lot +to be desired, but that's OK. + +So then he went +on and said, "When + +we reason with common sense +and lift a war club determined + +upon vigorous action, +nature ultimately hears us." + +Very picturesque, as if nature +had heard anyone, right? + +"Knowing what I was +looking for--" meaning he + +had a hypothetical bias, right-- +"I began to explore eagerly + +retina of fishes and mammals. + +Finally as a reward +of my faith, there + +deigned to appear most clearly +and brilliantly those two + +types of bipolar cells +demanded by theory + +and guessed by reason." + +What he means by +this is that there + +were two kinds of basic +kinds of bipolar cells-- + +and not the ON and OFF. + +But in this case, what +he was talking about, + +he was talking about rod +bipolars and cone bipolars. + +He said the rod photoreceptors +connect with rod bipolars, + +and the cone photoreceptors +with cone bipolars. + +So that's what [INAUDIBLE] +then established, + +and that finding was +basically correct. + +But then he went on to say that +these two kinds of bipolars + +hook up with two types +of ganglion cells, + +thereby forming separate +channels to the brain. + +So that was an interesting +conclusion, and for many years + +that was accepted. + +And interestingly enough, +as it so often happens + +with hypotheses, +this conclusion-- + +even though you had +the drawings looking + +through the microscope +showing that there were + +these separate channels-- +turned out to be largely + +not one-- almost entirely wrong. + +Now what do we mean by that? + +Well people began +to do all sorts + +of very careful intercellular +recordings in the retina, + +and using much +more sophisticated + +anatomical procedures +than Cajal was + +able to use, thanks to the +new developments in the field. + +And they discovered, first of +all-- let me back up a second. + +This is sort of the model +that he had proposed. + +He had the cone model +and the rod model, + +not distinguishing +between the ON and OFF. + +And so the model that +then subsequently emerged + +was that ganglion cells +in most of the retina + +actually receive a convergent +input- except in the fovia, + +because you don't have rods +there-- so that you don't have + +a doubling of ganglion +cells-- some for rods + +and some for cones-- but +both the rods and the cones, + +through separate pathways, +feed into the ganglion cell. + +So then this was analyzed +in much, much more detail. + +And now I'm going to point this +out to you by providing you + +with an overview of the +retinal connections. + +OK. + +So here we have the three +basic classes of cones. + +All right? + +And we have the rods. + +All right? + +Then, if you look at +the cones, each cone + +gives rise to at least two +bipolar cell-- an ON and OFF + +bipolar cell. + +But the rods in +most species only + +have a single kind +of bipolar cell, + +and they can refer to that +as an ON bipolar cell, + +because the synapses are all +sign-inverting synapses using + +the mGluR6 neurotransmitter +receptor site. + +So that's what we have there. + +Now if you look further down +here at the ganglion cells-- + +and what we have is of course, +that we have the ON and OFF + +bipolar cells from +the cones feed + +into the ON and +OFF ganglion cells. + +So now the questions are what +happens to the ON bipolar + +cells? + +How do they connect +to these cells + +since they do not form +a separate pathway? + +And this has been +again-- things got + +very complicated in +the course of evolution + +where it was very important +to try to conserve things + +as much as possible, +and that's why we do not + +have separate pathways +for rods and cones. + +If we did we'd need +a huge eye, and we'd + +need at least twice +as many ganglion cells + +than we have at the present +time, which is about a million + +in each eye. + +OK, so what really happened +is-- dumb-founding almost-- + +is that a so-called +amacrine cell -- + +I told you there are different +classes of amacrine cells-- + +one of them is a so-called +A2 amacrine cell. + +That is a cell that +receives a direct input + +from the ON bipolar cells. + +Now that amacrine cell +connects to ganglion cells + +in two different ways. + +It makes a gap junction +connection with the ON bipolar + +cells, and it makes a +glycinergic synaptic connection + +with the OFF ganglion cell. + +So let's label this. + +What we have here-- this is +inner plexiform layer again, + +and here is the outer +plexiform layer. + +And what we have here-- +just to remind you, + +that already know-- we have +a sign-inverting synapse + +for the ON, and sign-conserving +for the OFF bipolars + +that connect with the cones. + +And now we have here-- let's +proceed to the A2 amacrine + +cell that is feeding into +these cells from the rods. + +And what we have here is a +glycinergic synapse, so-called. + +That's a real synapse. + +It's inhibitory. + +And then here we have what +is called a gap junction. + +I'm sure all of you know +what these things are. + +Gap junction is what you +call an electrical synapse. + +So they transform the signal +without any neurotransmitters + +involved. + +So it directly activates-- in +this case, this fiber here-- + +and drives it. + +So what you create +in the inner retina + +then here is a +double ended system + +for the rods that is created in +the outer retina for the cones. + +So you create [INAUDIBLE]. + +Here are the OFF, and here are +the ON inputs to the ON and OFF + +ganglion cells. + +Now because of this +arrangement, what happens + +is that the size +of the receptive + +fields under dark +adaptive conditions + +is bigger because a bigger range +of connections from the rods + +to the ganglion cells. + +So all this is nice +wiring that finally, + +after many, many +years of experiments, + +has been clarified. + +Sorry it is so complicated. + +That's just how it is. + +Explains then the claim that +you have bigger receptive fields + +at night than in the daytime. + +And now that has been +generally accepted. + +OK so now the central +conclusions that we come to + +is that ON and OFF +channels have emerged + +in the course of evolution +to enable organisms + +to process light both +incrementally and decrementally + +for being able to see +things rapidly and quickly. + +All right? + +So that is the prime function. + +Nature has gone to +incredible extent + +to modify the basic organization +of the visual system + +and the retina to +create a way to be + +able to process +both light increment + +and decrement rapidly. + +Now that may provide you +with a little cute mnemonic, + +if you will. + +Here we have a fish. + +Fish also, believe it or not, +have ON and OFF channels. + +Now what happens is +if below here there + +is a predator-- +a large fish that + +is trying to catch this fish-- +because of the sun shining + +on it, it reflects +the light, and so + +this fish would see +this particular predator + +by virtue of light increment. + +Got it? + +By contrast, if you +have osprey up here + +that's trying to +catch this fish, + +that osprey against the sky +would be seen as a dark object. + +OK? + +And so now, since this fish +has both ON and OFF cells + +in its retina, it's +going to do this. + +You ready? + +He's going to escape, OK? + +So that then, in a +nutshell, tells us + +why we have ON and OFF channels +in the visual system-- namely + +to enable us to process both +light increment and light + +decrement effectively. + +And as I've mentioned +to you before, + +whenever you read or +write, you see things + +mostly by virtue +of your OFF system + +because you have dark print or a +dark pen on a light background. + +But of course the +obverse is also the case. + +So this was known +for ages and ages. + +And that's why +eventually, instead + +of having print +in which you have + +a black page with +white letters, you now + +a white page with black +letters, because that's + +much more economical to achieve. + +And you can read both +light incremental + +and light decremental +letters equally well + +because we have these +ON and OFF channels. + +OK. + +So on the basis of +this then, we are + +ready to summarize why we +have this remarkable duality + +in the retina, originating +in the ON and OFF channels, + +whose circuits we +by now, I presume, + +you understand pretty well. + +So just to reiterate for +the umpteenth time, which + +is easy to remember by +now, all photoreceptors + +hyperpolarize to light. + +Secondly, the cone driven +ON and OFF channels + +originate at the level of +the retinal bipolar cells. + +OK? + +For ON bipolars +you have a system, + +which involves +sign-inverting synapses. + +OK? + +The neuron transmitted by +the way of the photoreceptors + +is glutamate. + +And you come to the receptor +sites-- the mGluR6 receptor is + +the one that inverts the signal +for the ON bipolar cells. + +And the mGluR1 and 2 is the +neurotransmitter receptor site + +for the OFF bipolar cells. + +Now APB-- can +important to remember + +this-- is that glutamate analog. + +A lot of people make a mistake +and think it's an antagonist. + +It's a glutamate analog. + +So what happens is that +it blocks the ON bipolar. + +Now let me say just a couple +more words about this. + +We move our eyes about +three times a second. + +Every time you move your eye +some mechanisms in the retina + +wipe the slate +clean, so to speak, + +because if it didn't, +then the image that + +would fall on the retina +after you moved your eye + +would interfere +with the image that + +had fallen on the +eye beforehand. + +So there's an +incredibly rapid system + +that breaks down the +molecular arrangement + +of glutamate and many other +transmitters in the retina + +so that with each +movement of the eye, + +you can see things clearly. + +Now there is an exception +to that, of course, + +under extreme conditions. + +We have what is +called "after images," + +like when you look at +the sun for a while. + +Then you will see an after +image lingering on in your eye. + +But under normal +illumination conditions, + +the slate is wiped clean +with every shift in the eye. + +Quite amazing. + +All right. + +Then APB blocks the ON response +of retinal ganglion cells. + +The OFF response and +center-surround antagonism + +are unaffected. + +APB blocks lighted +responses in the cortex, + +but has no effect on +orientation, direction, + +and spatial frequency +selectivity. + +APB reduces the sensitivity +for light increment, + +and the ON and OFF channels for +rods arise in the inner retina. + +And I should add +here that there's + +only one kind of rod bipolar, +which is the ON-type. + +There are no OFF-type +rod biopolars. + +Then in most primates there +are only ON rod bipolars. + +The rod ON and OFF +channels are created + +in the inner retina +by the amacrine cells, + +predominately by the +so-called A2 amacrine cell, + +as I told you. + +Lastly, excitatory +signals are generated + +for both light increment +and for light decrement + +by virtue of the ON +and OFF channels. + +So those are the +major conclusions + +that we need to make about this +remarkable achievement of how + +the visual system works, +by virtue of having created + +the ON and the OFF channels, +by virtue of having then + +done this, by virtue of creating +from a single-ended system + +of the photoreceptors, +a double-ended system + +at the level of +the bipolar cells. + +So that then is-- +sorry how complicated + +it is-- the basic layout of +the retina and the ON and OFF + +channels. + +Next time we are going to talk +about yet another subdivision + +in retinal ganglion cells-- the +so-called midget and parasol + +cells. + +I think I've mentioned +to you before that we + +have several different classes +of retinal ganglion cells-- + +not just ON and OFF. + +And the so-called +midget and parasol cells + +have ON and OFF subdivisions. + +And then there are +several other cells + +that do all kinds +of other things. + +We will talk about +some of those. + +But the overwhelming, largest +number of cells in the retina + +are the midget and the +parasol, and so they + +deserve the greatest +scrutiny as to why + +we have those two systems. + +And that's we are going +to discuss the next time. + +So that pretty well finishes +what I had to cover today, + +and so if any of you +have any questions, + +I will be happy to try to answer +them for you, as long as it + +pertains, of course, to +the ON and OFF channels. + +Anybody not clear +on the rules of how + +APB works-- that it's an analog, +that it fills the receptor + +sites of the ON bipolar +cells, rendering + +them insensitive to +subsequent light stimulation? + +Now I should add maybe +one more thing here + +is that unlike the glutamate, +which is broken down + +in milliseconds, this +artificial substance-- APB-- + +there's no natural +optic mechanism for it. + +And so it lingers on, and +that's why it is so effective. + +And it has to be washed out +of the eye-- you typically + +have to wait 10-- 15 minutes +for the eye to return to normal + +because there's no rapid +optic mechanism for the APB, + +in contrast to the glutamate. + +Well it sounds like I +was reasonably clear. + +I hope you can absorb +this and marvel + +at the inventiveness, if +you will, of evolution + +to have created this +incredible mechanisms that we + +see in the retina. + +It's just dumb-founding. + +Yes, it's just incredible. + +So that then is what we +going to finish with today. + +And so I will see +you Wednesday, and we + +talk about the midget and +parasol systems, which + +is also very +interesting, by the way. + +And I hope you've +enjoyed hearing + +about what those +two systems are for. \ No newline at end of file diff --git a/nSin1QDLUDs.txt b/nSin1QDLUDs.txt new file mode 100644 index 0000000000000000000000000000000000000000..0750f77eb98a8d394ad5e8c75a0c1b8eef98f330 --- /dev/null +++ b/nSin1QDLUDs.txt @@ -0,0 +1,1219 @@ +align:start position:0% + +if you + + align:start position:0% +if you + + + align:start position:0% +if you +are wearing rings as i do it's a good + + align:start position:0% +are wearing rings as i do it's a good + + + align:start position:0% +are wearing rings as i do it's a good +idea to take them off + + align:start position:0% +idea to take them off + + + align:start position:0% +idea to take them off +because when you prepare the dough it's + + align:start position:0% +because when you prepare the dough it's + + + align:start position:0% +because when you prepare the dough it's +not great + + align:start position:0% +not great + + + align:start position:0% +not great +it's not very hydrating if you are + + align:start position:0% +it's not very hydrating if you are + + + align:start position:0% +it's not very hydrating if you are +wearing rings + + align:start position:0% +wearing rings + + + align:start position:0% +wearing rings +i once lost a stone + + align:start position:0% + + + + align:start position:0% + +very safe either but you want to of + + align:start position:0% +very safe either but you want to of + + + align:start position:0% +very safe either but you want to of +course + + align:start position:0% +course + + + align:start position:0% +course +wash the vegetables okay the broccoli + + align:start position:0% +wash the vegetables okay the broccoli + + + align:start position:0% +wash the vegetables okay the broccoli +you can just + + align:start position:0% +you can just + + + align:start position:0% +you can just +cut them into small pieces and maybe you + + align:start position:0% +cut them into small pieces and maybe you + + + align:start position:0% +cut them into small pieces and maybe you +can make a small + + align:start position:0% +can make a small + + + align:start position:0% +can make a small +sofrito with the alga + + align:start position:0% +sofrito with the alga + + + align:start position:0% +sofrito with the alga +that's one option the + + align:start position:0% +that's one option the + + + align:start position:0% +that's one option the +spinach you can just use them as they + + align:start position:0% +spinach you can just use them as they + + + align:start position:0% +spinach you can just use them as they +are + + align:start position:0% +are + + + align:start position:0% +are +in the pepperoni you need to wash them + + align:start position:0% +in the pepperoni you need to wash them + + + align:start position:0% +in the pepperoni you need to wash them +cut them remove the seeds + + align:start position:0% +cut them remove the seeds + + + align:start position:0% +cut them remove the seeds +and then you can cut them in stripes for + + align:start position:0% +and then you can cut them in stripes for + + + align:start position:0% +and then you can cut them in stripes for +example + + align:start position:0% +example + + + align:start position:0% +example +that's a good thing and again you can + + align:start position:0% +that's a good thing and again you can + + + align:start position:0% +that's a good thing and again you can +put them in the + + align:start position:0% +put them in the + + + align:start position:0% +put them in the +pan so they roast a little bit + + align:start position:0% +pan so they roast a little bit + + + align:start position:0% +pan so they roast a little bit +a tiny bit of oil you can do the same + + align:start position:0% +a tiny bit of oil you can do the same + + + align:start position:0% +a tiny bit of oil you can do the same +thing + + align:start position:0% + + + + align:start position:0% + +i like them cut longitudinally but if + + align:start position:0% +i like them cut longitudinally but if + + + align:start position:0% +i like them cut longitudinally but if +you want to cut them + + align:start position:0% +you want to cut them + + + align:start position:0% +you want to cut them +in disks that's fine and look + + align:start position:0% +in disks that's fine and look + + + align:start position:0% +in disks that's fine and look +for the melon it's a little bit more + + align:start position:0% +for the melon it's a little bit more + + + align:start position:0% +for the melon it's a little bit more +complex but not too much + + align:start position:0% +complex but not too much + + + align:start position:0% +complex but not too much +so you want to cut it in disks + + align:start position:0% +so you want to cut it in disks + + + align:start position:0% +so you want to cut it in disks +as see as thin as you can so it cooks + + align:start position:0% +as see as thin as you can so it cooks + + + align:start position:0% +as see as thin as you can so it cooks +fast yeah yes + + align:start position:0% + + + + align:start position:0% + +okay we got it and then you first put it + + align:start position:0% +okay we got it and then you first put it + + + align:start position:0% +okay we got it and then you first put it +with a little bit of salt + + align:start position:0% +with a little bit of salt + + + align:start position:0% +with a little bit of salt +um in the sink because the idea is that + + align:start position:0% +um in the sink because the idea is that + + + align:start position:0% +um in the sink because the idea is that +you want + + align:start position:0% +you want + + + align:start position:0% +you want +the bitter to go away sometimes the + + align:start position:0% +the bitter to go away sometimes the + + + align:start position:0% +the bitter to go away sometimes the +eggplants can be a little bit bitter + + align:start position:0% +eggplants can be a little bit bitter + + + align:start position:0% +eggplants can be a little bit bitter +then you have to rinse it very well dry + + align:start position:0% +then you have to rinse it very well dry + + + align:start position:0% +then you have to rinse it very well dry +it + + align:start position:0% +it + + + align:start position:0% +it +and then just roast it on the pan high + + align:start position:0% +and then just roast it on the pan high + + + align:start position:0% +and then just roast it on the pan high +fire + + align:start position:0% +fire + + + align:start position:0% +fire +for short times that's it + + align:start position:0% + + + + align:start position:0% + +okay we wash them + + align:start position:0% + + + + align:start position:0% + +cut them in the shape that you prefer + + align:start position:0% +cut them in the shape that you prefer + + + align:start position:0% +cut them in the shape that you prefer +i recommend to do small slices + + align:start position:0% +i recommend to do small slices + + + align:start position:0% +i recommend to do small slices +because again they cook faster and if + + align:start position:0% +because again they cook faster and if + + + align:start position:0% +because again they cook faster and if +you want + + align:start position:0% +you want + + + align:start position:0% +you want +you can saute them for example with + + align:start position:0% +you can saute them for example with + + + align:start position:0% +you can saute them for example with +chipotle + + align:start position:0% + + + + align:start position:0% + +so this is the vegetable team + + align:start position:0% +so this is the vegetable team + + + align:start position:0% +so this is the vegetable team +the other team will + + align:start position:0% +the other team will + + + align:start position:0% +the other team will +start preparing pizza + + align:start position:0% +start preparing pizza + + + align:start position:0% +start preparing pizza +pizza you'll need + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% + + + + align:start position:0% + +i will help you with this and then we + + align:start position:0% +i will help you with this and then we + + + align:start position:0% +i will help you with this and then we +will add + + align:start position:0% +will add + + + align:start position:0% +will add +some whatever + + align:start position:0% + + + + align:start position:0% + +so don't forget that i'm giving you very + + align:start position:0% +so don't forget that i'm giving you very + + + align:start position:0% +so don't forget that i'm giving you very +precise measurements but this is only + + align:start position:0% +precise measurements but this is only + + + align:start position:0% +precise measurements but this is only +because it's the first time that you're + + align:start position:0% +because it's the first time that you're + + + align:start position:0% +because it's the first time that you're +making pizza + + align:start position:0% +making pizza + + + align:start position:0% +making pizza +once you have done pizza if you're + + align:start position:0% +once you have done pizza if you're + + + align:start position:0% +once you have done pizza if you're +trying for a few times you won't need + + align:start position:0% +trying for a few times you won't need + + + align:start position:0% +trying for a few times you won't need +la bilancia the scale anymore you will + + align:start position:0% +la bilancia the scale anymore you will + + + align:start position:0% +la bilancia the scale anymore you will +do everything + + align:start position:0% +do everything + + + align:start position:0% +do everything +yes okay bye + + align:start position:0% + + + + align:start position:0% + +i'm gonna put the two events at two + + align:start position:0% +i'm gonna put the two events at two + + + align:start position:0% +i'm gonna put the two events at two +different temperatures so they see the + + align:start position:0% +different temperatures so they see the + + + align:start position:0% +different temperatures so they see the +result + + align:start position:0% +result + + + align:start position:0% +result +cooking the pizza at 400 fahrenheit and + + align:start position:0% +cooking the pizza at 400 fahrenheit and + + + align:start position:0% +cooking the pizza at 400 fahrenheit and +500 paranoids + + align:start position:0% +500 paranoids + + + align:start position:0% +500 paranoids +you were + + align:start position:0% + + + + align:start position:0% + +right so you want the dough + + align:start position:0% +right so you want the dough + + + align:start position:0% +right so you want the dough +to be to stick together but you don't + + align:start position:0% +to be to stick together but you don't + + + align:start position:0% +to be to stick together but you don't +want it to be sticky + + align:start position:0% +want it to be sticky + + + align:start position:0% +want it to be sticky +start with not too much then you don't + + align:start position:0% +start with not too much then you don't + + + align:start position:0% +start with not too much then you don't +have to worry + + align:start position:0% +have to worry + + + align:start position:0% +have to worry +if the dough becomes too sticky + + align:start position:0% + + + + align:start position:0% + +and then i was telling them you can take + + align:start position:0% +and then i was telling them you can take + + + align:start position:0% +and then i was telling them you can take +it out of + + align:start position:0% +it out of + + + align:start position:0% +it out of +the bowl that you're using the measuring + + align:start position:0% +the bowl that you're using the measuring + + + align:start position:0% +the bowl that you're using the measuring +cup + + align:start position:0% +cup + + + align:start position:0% +cup +and you can mix it on the counter + + align:start position:0% +and you can mix it on the counter + + + align:start position:0% +and you can mix it on the counter +you just put it on you wait + + align:start position:0% + + + + align:start position:0% + +a little bit more water + + align:start position:0% + + + + align:start position:0% + +don't worry you don't have to be + + align:start position:0% +don't worry you don't have to be + + + align:start position:0% +don't worry you don't have to be +delicate you can be + + align:start position:0% +delicate you can be + + + align:start position:0% +delicate you can be +strong with the pizza i'll show you now + + align:start position:0% +strong with the pizza i'll show you now + + + align:start position:0% +strong with the pizza i'll show you now +the + + align:start position:0% + + + + align:start position:0% + +this isn't much dough you can + + align:start position:0% +this isn't much dough you can + + + align:start position:0% +this isn't much dough you can +you can either + + align:start position:0% + + + + align:start position:0% + +mix it this way and then you can make + + align:start position:0% +mix it this way and then you can make + + + align:start position:0% +mix it this way and then you can make +the circle movement + + align:start position:0% +the circle movement + + + align:start position:0% +the circle movement +with your palm you see + + align:start position:0% + + + + align:start position:0% + +good and yeah you can probably add + + align:start position:0% + + + + align:start position:0% + +and we make + + align:start position:0% + + + + align:start position:0% + +so that we can make large rectangles + + align:start position:0% +so that we can make large rectangles + + + align:start position:0% +so that we can make large rectangles +your fingers + + align:start position:0% + + + + align:start position:0% + +okay in this way we are sure that there + + align:start position:0% +okay in this way we are sure that there + + + align:start position:0% +okay in this way we are sure that there +are no bubbles in the dough + + align:start position:0% + + + + align:start position:0% + +so we put the pasta + + align:start position:0% +so we put the pasta + + + align:start position:0% +so we put the pasta +and then you put mozzarella as much as + + align:start position:0% +and then you put mozzarella as much as + + + align:start position:0% +and then you put mozzarella as much as +little + + align:start position:0% +little + + + align:start position:0% +little +spice and you're gonna put the toppings + + align:start position:0% +spice and you're gonna put the toppings + + + align:start position:0% +spice and you're gonna put the toppings +your favorite toppings everything is + + align:start position:0% +your favorite toppings everything is + + + align:start position:0% +your favorite toppings everything is +allowed + + align:start position:0% +allowed + + + align:start position:0% +allowed +sprinkle them with oregano you put + + align:start position:0% +sprinkle them with oregano you put + + + align:start position:0% +sprinkle them with oregano you put +a couple of spoonful of olive oil on + + align:start position:0% +a couple of spoonful of olive oil on + + + align:start position:0% +a couple of spoonful of olive oil on +each + + align:start position:0% +each + + + align:start position:0% +each +pizza and a pinch of + + align:start position:0% +pizza and a pinch of + + + align:start position:0% +pizza and a pinch of +salad okay pasta + + align:start position:0% +salad okay pasta + + + align:start position:0% +salad okay pasta +also stopping we put it at the very + + align:start position:0% +also stopping we put it at the very + + + align:start position:0% +also stopping we put it at the very +end we don't put it the basilico + + align:start position:0% +end we don't put it the basilico + + + align:start position:0% +end we don't put it the basilico +it doesn't taste good look at troy look + + align:start position:0% +it doesn't taste good look at troy look + + + align:start position:0% +it doesn't taste good look at troy look +at troy + + align:start position:0% +at troy + + + align:start position:0% +at troy +okay oh we're not gonna make more yes + + align:start position:0% +okay oh we're not gonna make more yes + + + align:start position:0% +okay oh we're not gonna make more yes +we're gonna make smart + + align:start position:0% +we're gonna make smart + + + align:start position:0% +we're gonna make smart +no no no you guys and we'll help + + align:start position:0% +no no no you guys and we'll help + + + align:start position:0% +no no no you guys and we'll help +yourself could we add some colors + + align:start position:0% + + + + align:start position:0% + +oh + + align:start position:0% + + + + align:start position:0% + +they are very very tasty the taste is + + align:start position:0% +they are very very tasty the taste is + + + align:start position:0% +they are very very tasty the taste is +very intense so you don't + + align:start position:0% +very intense so you don't + + + align:start position:0% +very intense so you don't +need maybe if you want to put them you + + align:start position:0% +need maybe if you want to put them you + + + align:start position:0% +need maybe if you want to put them you +can also cut them + + align:start position:0% +can also cut them + + + align:start position:0% +can also cut them +and like little pieces in different + + align:start position:0% +and like little pieces in different + + + align:start position:0% +and like little pieces in different +locations because if you taste it if you + + align:start position:0% +locations because if you taste it if you + + + align:start position:0% +locations because if you taste it if you +take a whole lot + + align:start position:0% +take a whole lot + + + align:start position:0% +take a whole lot +it's good but not everybody like likes + + align:start position:0% +it's good but not everybody like likes + + + align:start position:0% +it's good but not everybody like likes +it because + + align:start position:0% +it because + + + align:start position:0% +it because +the taste is kind of intense if you want + + align:start position:0% +the taste is kind of intense if you want + + + align:start position:0% +the taste is kind of intense if you want +to use the prosciutto + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% + + + + align:start position:0% + +the top is like 400 fahrenheits and the + + align:start position:0% +the top is like 400 fahrenheits and the + + + align:start position:0% +the top is like 400 fahrenheits and the +bottom one at 500 + + align:start position:0% +bottom one at 500 + + + align:start position:0% +bottom one at 500 +they will cook differently i made it on + + align:start position:0% +they will cook differently i made it on + + + align:start position:0% +they will cook differently i made it on +purpose so that you can + + align:start position:0% +purpose so that you can + + + align:start position:0% +purpose so that you can +decide like what you like best everybody + + align:start position:0% +decide like what you like best everybody + + + align:start position:0% +decide like what you like best everybody +has a different taste + + align:start position:0% +has a different taste + + + align:start position:0% +has a different taste +you can experiment you can make + + align:start position:0% +you can experiment you can make + + + align:start position:0% +you can experiment you can make +different thicknesses of the pizza + + align:start position:0% +different thicknesses of the pizza + + + align:start position:0% +different thicknesses of the pizza +and you can bake them at the different + + align:start position:0% +and you can bake them at the different + + + align:start position:0% +and you can bake them at the different +temperatures + + align:start position:0% +temperatures + + + align:start position:0% +temperatures +another small detail i give you the + + align:start position:0% +another small detail i give you the + + + align:start position:0% +another small detail i give you the +temperature in fahrenheit because + + align:start position:0% +temperature in fahrenheit because + + + align:start position:0% +temperature in fahrenheit because +that's what we have here in italy + + align:start position:0% +that's what we have here in italy + + + align:start position:0% +that's what we have here in italy +the temperatures are in gravity + + align:start position:0% +the temperatures are in gravity + + + align:start position:0% +the temperatures are in gravity +gradient + + align:start position:0% + + + + align:start position:0% + +thank oh + + align:start position:0% + + + + align:start position:0% + +bye \ No newline at end of file diff --git a/o84SekTsgPo.txt b/o84SekTsgPo.txt new file mode 100644 index 0000000000000000000000000000000000000000..ce366df626957922589ee374b07b25833f7a4f66 --- /dev/null +++ b/o84SekTsgPo.txt @@ -0,0 +1,301 @@ +What do the growth of a plant and the rusting +of a truck have in common? Both processes + +involve mass transfer. In this video, you'll +learn how to apply the concept of a control + +volume and the law of conservation of mass +to real-world scenarios. + +This video is part of the Conservation video +series. + +In order to analyze or modify a system, it +is important to understand how the laws of + +conservation place constraints on that system. + +Hi. My name is Mark Bathe and I am a professor +in the Department of Biological Engineering + +at MIT. + +By watching this video, you will be able to +apply the law of conservation of mass to real-world + +scenarios. + +Before watching this video, however; you should +have had experience with basic reaction stoichiometry. + +In the 18th century, Antoine Lavoisier, a +French scientist, showed that there is no + +overall change in mass when a reaction takes +place in a sealed container. + +This observation is called the law of mass +conservation. + +What would Lavoisier say about a plant's growth... +...or a car rusting? + +Can conservation of mass be applied to these +scenarios? + +Of course it can. + +By using a conceptual tool called a "control +volume," we can more easily apply the law + +of mass conservation to these scenarios. + +What is a control volume? A control volume +is a fictitious boundary that separates a + +system of interest from its surroundings. +A control volume is NOT a tangible, solid + +boundary. Nor does the control volume have +to be a specific shape or size. A control + +volume can transmit energy or mass. A control +volume should be seen merely as a tool, and + +defining a control volume is a matter of convenience. +Depending on the question being investigated + +some control volumes may be more convenient +than others. + +Before we go back to the growing plant or +the rusting car example, let's go through + +a more visual example to demonstrate the idea +of a control volume. + +Here we have a sink filling with water. +What if we wanted to know how much water is + +accumulating in the basin? What control volume +might we choose to help us answer this question? + +Well, what if we were to define the faucet +as our control volume? We could look at the + +flow into and out of the control volume. Would +this give us enough information to figure + +out how much water is accumulating in our +basin? No. + +What if we defined the whole bathroom as our +control volume? We could look at the flow + +going through all of the plumbing in the bathroom. +Would this give us enough information to figure + +out how much water is accumulating in our +basin? + +Yes, but we'd also have a lot of information +to deal with. This probably wouldn't be the + +most efficient way to solve the problem. + +What if instead we defined the basin itself +as the control volume? Ah-ha. We could look + +at the flow going into and out of the control +volume and figure out how much water is actually + +accumulating in our basin. We have enough +information to figure out what we want to + +know, but not so much information that it +is cumbersome to deal with. + +Now, we will see how we can use the concept +of a control volume and general chemistry + +knowledge to better understand the application +of the conservation of mass to the growing + +plant and rusting car scenarios. + +Back to the growing plant. Let's say that +over some period of time, the plant grows + +and gains a mass of 25grams. Although the +plant isn't living in a sealed container, + +we can still apply the law of mass conservation +to the growing plant by specifying a control + +volume and accounting for the mass entering +and exiting that control volume. + +Most plants make their food using photosynthesis. +The overall reaction for photosynthesis is + +carbon dioxide plus water plus light energy +yields glucose plus oxygen. We'll assume that + +the plant's mass comes from glucose and it's +downstream products. + +Now please take a minute to think about what +control volume we might specify to apply the + +law of mass conservation to the plant's growth. +[short pause] + +If we think of the plant as our control volume, +we can apply the law of conservation of mass + +to perform a mass balance on the system. +Any mass that is accumulated in our system + +must equal any mass that entered the system +minus any mass that left the system. This + +is the law of mass conservation. + +What mass is entering the control volume? +Carbon dioxide and water. + +What mass is exiting the system? Oxygen. + +Drawing a diagram like this helps us keep +track of the information that we know and + +the information that we don't know. + +Note that we ignored the light energy because +we are performing a mass balance. We can substitute + +25 grams in for the accumulation term in the +mass balance equation. Now please pause the + +video here and see if you can figure out how +much carbon dioxide and water entered the + +system and how much oxygen exited the system. +Please continue playing the video to see the + +worked solutions. + +Using basic stoichiometry, we can see that +37 grams of carbon dioxide entered the system... + +15 grams of water also entered the system... + +And 27 grams of oxygen exited the system. + +We can compare these results to our mass balance +and see that our inputs minus our output equals + +the mass gained by the plant. +So, the law of mass conservation not only + +holds, but it gives us important insight into +the process of a growing plant. Fantastic! + +Now, let's turn to our next example, that +of a rusting car. + +The car has rusted, but the rust has fallen +off of the car, resulting in a decrease in + +the mass of the car. + +Measurements show that the car has lost mass, +but has mass really not been conserved? + +Let's think about this scenario a little more +carefully. What is happening when a car rusts? + +Can we write an equation to explain what is +happening chemically? + +Rusting happens by iron oxidation. This reaction +can be written as 3O2 + 4Fe -> 2Fe2O3. Measurements + +show that the car lost 10g of mass. +Now please take a minute to think about what + +control volume we might specify to apply the +law of mass conservation to the rusting car. + +[short pause] + +If we define the car as our system or control +volume, a concept that we introduced earlier, + +we can perform a mass balance on the car. +Remember, any mass that is accumulated in + +our system should equal any mass that entered +the system minus any mass that left the system. + +Our system, the car, lost 10g of mass. This +is a negative accumulation. + +During the rusting process, did any mass enter +our system? Yes, the mass due to the oxygen + +that reacted with the iron on the car's body. + +In our scenario, where a car has rusted and +the rust fell off of the car, has any mass + +left our system? Yes. The mass of the rust, +or iron oxide. + +Now please pause the video here and see if +you can figure out how much oxygen entered + +the system and how much iron oxide exited +the system. Please continue playing the video + +to see the worked solutions. + +Using basic stoichiometry, we can see that +4.3 grams of oxygen entered the system... + +and 14.3 grams of iron oxide exited the system. + +We can compare this to our mass balance to +see that our mass in minus our mass out equals + +the negative accumulation of mass of our car. + +Again, the law of conservation of mass has +served as a useful tool to learn something + +important about our system. + +This video illustrated how the law of conservation +of mass can be applied to real-world scenarios. + +Although real-world scenarios might seem overwhelming +at first, we can use a problem-solving tool + +called a control volume to help narrow our +focus. The law of conservation of mass allows + +us to perform a mass balance on the control +volume. In other words, any mass that has + +accumulated in our system must equal any mass +that entered the system minus any mass that + +exited the system. + +This simple idea will provide a basis for +understanding systems throughout your time + +at SUTD and beyond. + +FAANTASTIC! (will have to "cut and paste" +this audio from earlier) \ No newline at end of file diff --git a/pP7mt_Ie04Y.txt b/pP7mt_Ie04Y.txt new file mode 100644 index 0000000000000000000000000000000000000000..11c9ef95f03bf4d83442c83e1cb01285cc427acd --- /dev/null +++ b/pP7mt_Ie04Y.txt @@ -0,0 +1,923 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT OpenCourseWare continue to + + align:start position:0% +will help MIT OpenCourseWare continue to + + + align:start position:0% +will help MIT OpenCourseWare continue to +offer high quality educational resources + + align:start position:0% +offer high quality educational resources + + + align:start position:0% +offer high quality educational resources +for free + + align:start position:0% +for free + + + align:start position:0% +for free +to make a donation or to view additional + + align:start position:0% +to make a donation or to view additional + + + align:start position:0% +to make a donation or to view additional +materials from hundreds of MIT courses + + align:start position:0% +materials from hundreds of MIT courses + + + align:start position:0% +materials from hundreds of MIT courses +visit MIT opencourseware at ocw.mit.edu + + align:start position:0% + + + + align:start position:0% + +there's been any developments upon to + + align:start position:0% +there's been any developments upon to + + + align:start position:0% +there's been any developments upon to +see why has been helping the situation + + align:start position:0% +see why has been helping the situation + + + align:start position:0% +see why has been helping the situation +that are making the situation fit in + + align:start position:0% +that are making the situation fit in + + + align:start position:0% +that are making the situation fit in +anyway the recent areas what is it all + + align:start position:0% +anyway the recent areas what is it all + + + align:start position:0% +anyway the recent areas what is it all +claim down + + align:start position:0% +claim down + + + align:start position:0% +claim down +is there well I think it goes many + + align:start position:0% +is there well I think it goes many + + + align:start position:0% +is there well I think it goes many +directions so actually I think the most + + align:start position:0% +directions so actually I think the most + + + align:start position:0% +directions so actually I think the most +dramatic fact about the last election + + align:start position:0% +dramatic fact about the last election + + + align:start position:0% +dramatic fact about the last election +the 2016 election was not the election + + align:start position:0% +the 2016 election was not the election + + + align:start position:0% +the 2016 election was not the election +of Trump + + align:start position:0% +of Trump + + + align:start position:0% +of Trump +the most striking fact was the Sanders + + align:start position:0% +the most striking fact was the Sanders + + + align:start position:0% +the most striking fact was the Sanders +campaign I mean the fact that a + + align:start position:0% +campaign I mean the fact that a + + + align:start position:0% +campaign I mean the fact that a +billionaire was elected okay and it's + + align:start position:0% +billionaire was elected okay and it's + + + align:start position:0% +billionaire was elected okay and it's +not a big break from American history + + align:start position:0% +not a big break from American history + + + align:start position:0% +not a big break from American history +that goes on all the time but if the + + align:start position:0% +that goes on all the time but if the + + + align:start position:0% +that goes on all the time but if the +Sanders campaign broke sharply with over + + align:start position:0% +Sanders campaign broke sharply with over + + + align:start position:0% +Sanders campaign broke sharply with over +a hundred years of American political + + align:start position:0% +a hundred years of American political + + + align:start position:0% +a hundred years of American political +history I mean if we had you know media + + align:start position:0% +history I mean if we had you know media + + + align:start position:0% +history I mean if we had you know media +that we're talking about reality that + + align:start position:0% +that we're talking about reality that + + + align:start position:0% +that we're talking about reality that +would be the headline American elections + + align:start position:0% +would be the headline American elections + + + align:start position:0% +would be the headline American elections +are brought this plenty of substantial + + align:start position:0% +are brought this plenty of substantial + + + align:start position:0% +are brought this plenty of substantial +political mainstream political science + + align:start position:0% +political mainstream political science + + + align:start position:0% +political mainstream political science +research on this now if you look just at + + align:start position:0% +research on this now if you look just at + + + align:start position:0% +research on this now if you look just at +simple variables like say campaign + + align:start position:0% +simple variables like say campaign + + + align:start position:0% +simple variables like say campaign +funding something as simple as that + + align:start position:0% +funding something as simple as that + + + align:start position:0% +funding something as simple as that +the predictability of electability by + + align:start position:0% +the predictability of electability by + + + align:start position:0% +the predictability of electability by +campaign funding is literally almost a + + align:start position:0% +campaign funding is literally almost a + + + align:start position:0% +campaign funding is literally almost a +straight line there's a recent study by + + align:start position:0% +straight line there's a recent study by + + + align:start position:0% +straight line there's a recent study by +Tom Ferguson over to UMass one of the + + align:start position:0% +Tom Ferguson over to UMass one of the + + + align:start position:0% +Tom Ferguson over to UMass one of the +main scholars it works on this who + + align:start position:0% +main scholars it works on this who + + + align:start position:0% +main scholars it works on this who +studied congressional elected for + + align:start position:0% +studied congressional elected for + + + align:start position:0% +studied congressional elected for +presidential elections have been shown + + align:start position:0% +presidential elections have been shown + + + align:start position:0% +presidential elections have been shown +for a long time but there was the first + + align:start position:0% +for a long time but there was the first + + + align:start position:0% +for a long time but there was the first +main study of congressional elections + + align:start position:0% +main study of congressional elections + + + align:start position:0% +main study of congressional elections +they went from 1980 to the present all + + align:start position:0% +they went from 1980 to the present all + + + align:start position:0% +they went from 1980 to the present all +over the country simply asking what's + + align:start position:0% +over the country simply asking what's + + + align:start position:0% +over the country simply asking what's +the relation between campaign spending + + align:start position:0% +the relation between campaign spending + + + align:start position:0% +the relation between campaign spending +and elect + + align:start position:0% +and elect + + + align:start position:0% +and elect +ability and it is literally a straight + + align:start position:0% +ability and it is literally a straight + + + align:start position:0% +ability and it is literally a straight +line you just don't get results like + + align:start position:0% +line you just don't get results like + + + align:start position:0% +line you just don't get results like +that in the social sciences the more + + align:start position:0% +that in the social sciences the more + + + align:start position:0% +that in the social sciences the more +campaign spending the more you get + + align:start position:0% +campaign spending the more you get + + + align:start position:0% +campaign spending the more you get +elected and that goes back well it well + + align:start position:0% +elected and that goes back well it well + + + align:start position:0% +elected and that goes back well it well +into the late 19th century act is a + + align:start position:0% +into the late 19th century act is a + + + align:start position:0% +into the late 19th century act is a +famous campaign manager Mark Hannah the + + align:start position:0% +famous campaign manager Mark Hannah the + + + align:start position:0% +famous campaign manager Mark Hannah the +back 1890s he was asked once what do you + + align:start position:0% +back 1890s he was asked once what do you + + + align:start position:0% +back 1890s he was asked once what do you +have with the what's the secret for + + align:start position:0% +have with the what's the secret for + + + align:start position:0% +have with the what's the secret for +running a successful election campaign + + align:start position:0% +running a successful election campaign + + + align:start position:0% +running a successful election campaign +and he said you have to have two things + + align:start position:0% +and he said you have to have two things + + + align:start position:0% +and he said you have to have two things +the first one is money and I can't + + align:start position:0% +the first one is money and I can't + + + align:start position:0% +the first one is money and I can't +remember the second one that's American + + align:start position:0% +remember the second one that's American + + + align:start position:0% +remember the second one that's American +politics overwhelming near-certainty + + align:start position:0% +politics overwhelming near-certainty + + + align:start position:0% +politics overwhelming near-certainty +well all of a sudden you get a guy who's + + align:start position:0% +well all of a sudden you get a guy who's + + + align:start position:0% +well all of a sudden you get a guy who's +unknown has no support from any of the + + align:start position:0% +unknown has no support from any of the + + + align:start position:0% +unknown has no support from any of the +sources of wealth no support from the + + align:start position:0% +sources of wealth no support from the + + + align:start position:0% +sources of wealth no support from the +wealthy you know corporate support + + align:start position:0% +wealthy you know corporate support + + + align:start position:0% +wealthy you know corporate support +dismissed by the media's ridiculous very + + align:start position:0% +dismissed by the media's ridiculous very + + + align:start position:0% +dismissed by the media's ridiculous very +negative media campaign he was basically + + align:start position:0% +negative media campaign he was basically + + + align:start position:0% +negative media campaign he was basically +unknown even used the scare word + + align:start position:0% +unknown even used the scare word + + + align:start position:0% +unknown even used the scare word +socialist he would have won the + + align:start position:0% +socialist he would have won the + + + align:start position:0% +socialist he would have won the +Democratic Party nomination if it hadn't + + align:start position:0% +Democratic Party nomination if it hadn't + + + align:start position:0% +Democratic Party nomination if it hadn't +been for the Clinton Obama shenanigans + + align:start position:0% +been for the Clinton Obama shenanigans + + + align:start position:0% +been for the Clinton Obama shenanigans +to keep the party from reflecting its + + align:start position:0% +to keep the party from reflecting its + + + align:start position:0% +to keep the party from reflecting its +popular constituency that's an + + align:start position:0% +popular constituency that's an + + + align:start position:0% +popular constituency that's an +incredible break from history and right + + align:start position:0% +incredible break from history and right + + + align:start position:0% +incredible break from history and right +now incidentally he's by far the most + + align:start position:0% +now incidentally he's by far the most + + + align:start position:0% +now incidentally he's by far the most +popular political figure in the country + + align:start position:0% +popular political figure in the country + + + align:start position:0% +popular political figure in the country +way above anyone else well those are + + align:start position:0% +way above anyone else well those are + + + align:start position:0% +way above anyone else well those are +signs that other things are chained + + align:start position:0% +signs that other things are chained + + + align:start position:0% +signs that other things are chained +especially among young people is way out + + align:start position:0% +especially among young people is way out + + + align:start position:0% +especially among young people is way out +that's the future of electorate so these + + align:start position:0% +that's the future of electorate so these + + + align:start position:0% +that's the future of electorate so these +are things that are going off in the + + align:start position:0% +are things that are going off in the + + + align:start position:0% +are things that are going off in the +other direction there's plenty of + + align:start position:0% +other direction there's plenty of + + + align:start position:0% +other direction there's plenty of +opportunities if they're grasped and + + align:start position:0% +opportunities if they're grasped and + + + align:start position:0% +opportunities if they're grasped and +it's kind of easy to sink into sort of + + align:start position:0% +it's kind of easy to sink into sort of + + + align:start position:0% +it's kind of easy to sink into sort of +hopelessness what's the point no but + + align:start position:0% +hopelessness what's the point no but + + + align:start position:0% +hopelessness what's the point no but +it's just really bad + + align:start position:0% +it's just really bad + + + align:start position:0% +it's just really bad +mistake first of all the issues are + + align:start position:0% +mistake first of all the issues are + + + align:start position:0% +mistake first of all the issues are +extremely important done there's an + + align:start position:0% +extremely important done there's an + + + align:start position:0% +extremely important done there's an +awful lot can be done even in the kind + + align:start position:0% +awful lot can be done even in the kind + + + align:start position:0% +awful lot can be done even in the kind +of thing that Harley hoshide was doing + + align:start position:0% +of thing that Harley hoshide was doing + + + align:start position:0% +of thing that Harley hoshide was doing +reaching people who were deeply embedded + + align:start position:0% +reaching people who were deeply embedded + + + align:start position:0% +reaching people who were deeply embedded +in the the ultra red constituency a + + align:start position:0% +in the the ultra red constituency a + + + align:start position:0% +in the the ultra red constituency a +deeply religious conservative + + align:start position:0% +deeply religious conservative + + + align:start position:0% +deeply religious conservative +traditional a/d government for the + + align:start position:0% +traditional a/d government for the + + + align:start position:0% +traditional a/d government for the +reasons that they see which you can + + align:start position:0% +reasons that they see which you can + + + align:start position:0% +reasons that they see which you can +understand them be changed incidentally + + align:start position:0% +understand them be changed incidentally + + + align:start position:0% +understand them be changed incidentally +if you look back in the past these same + + align:start position:0% +if you look back in the past these same + + + align:start position:0% +if you look back in the past these same +sectors of the population where the most + + align:start position:0% +sectors of the population where the most + + + align:start position:0% +sectors of the population where the most +carried forward the most extreme radical + + align:start position:0% +carried forward the most extreme radical + + + align:start position:0% +carried forward the most extreme radical +Democratic programs in American history + + align:start position:0% +Democratic programs in American history + + + align:start position:0% +Democratic programs in American history +the term populism is thrown around now + + align:start position:0% +the term populism is thrown around now + + + align:start position:0% +the term populism is thrown around now +but it used to mean something and the + + align:start position:0% +but it used to mean something and the + + + align:start position:0% +but it used to mean something and the +populist movement in the United States + + align:start position:0% +populist movement in the United States + + + align:start position:0% +populist movement in the United States +which began with farmers and Texas and + + align:start position:0% +which began with farmers and Texas and + + + align:start position:0% +which began with farmers and Texas and +spread through the Midwest Kansas and + + align:start position:0% +spread through the Midwest Kansas and + + + align:start position:0% +spread through the Midwest Kansas and +places like that was a really powerful + + align:start position:0% +places like that was a really powerful + + + align:start position:0% +places like that was a really powerful +radical democratic movement + + align:start position:0% +radical democratic movement + + + align:start position:0% +radical democratic movement +all linked up with the Knights of Labor + + align:start position:0% +all linked up with the Knights of Labor + + + align:start position:0% +all linked up with the Knights of Labor +the main labor movement whose slogan was + + align:start position:0% +the main labor movement whose slogan was + + + align:start position:0% +the main labor movement whose slogan was +that working people or owned and run the + + align:start position:0% +that working people or owned and run the + + + align:start position:0% +that working people or owned and run the +factories I mean though it was smashed + + align:start position:0% +factories I mean though it was smashed + + + align:start position:0% +factories I mean though it was smashed +by force finally but this is by far the + + align:start position:0% +by force finally but this is by far the + + + align:start position:0% +by force finally but this is by far the +most real democratic movement in + + align:start position:0% +most real democratic movement in + + + align:start position:0% +most real democratic movement in +American history and maybe the world and + + align:start position:0% +American history and maybe the world and + + + align:start position:0% +American history and maybe the world and +it comes out of the Texas and Kansas + + align:start position:0% +it comes out of the Texas and Kansas + + + align:start position:0% +it comes out of the Texas and Kansas +farmers same people + + align:start position:0% + + + + align:start position:0% + +you \ No newline at end of file diff --git a/ppxK4R8XWfU.txt b/ppxK4R8XWfU.txt new file mode 100644 index 0000000000000000000000000000000000000000..fd333fbc9dca356c0c697be4653b1e0bd4a12e73 --- /dev/null +++ b/ppxK4R8XWfU.txt @@ -0,0 +1,17107 @@ +align:start position:0% + +so we're talking about navigation how + + align:start position:0% +so we're talking about navigation how + + + align:start position:0% +so we're talking about navigation how +you know where you are and how you can + + align:start position:0% +you know where you are and how you can + + + align:start position:0% +you know where you are and how you can +get from here to wherever else you want + + align:start position:0% +get from here to wherever else you want + + + align:start position:0% +get from here to wherever else you want +to go + + align:start position:0% +to go + + + align:start position:0% +to go +and last time we talked about just the + + align:start position:0% +and last time we talked about just the + + + align:start position:0% +and last time we talked about just the +general problems that arise in + + align:start position:0% +general problems that arise in + + + align:start position:0% +general problems that arise in +navigation and we talked about the para + + align:start position:0% +navigation and we talked about the para + + + align:start position:0% +navigation and we talked about the para +hippocampal place area + + align:start position:0% +hippocampal place area + + + align:start position:0% +hippocampal place area +and other + + align:start position:0% +and other + + + align:start position:0% +and other +parts of the brain that are involved in + + align:start position:0% +parts of the brain that are involved in + + + align:start position:0% +parts of the brain that are involved in +navigation so today we're going to + + align:start position:0% +navigation so today we're going to + + + align:start position:0% +navigation so today we're going to +continue that but we're going to talk + + align:start position:0% +continue that but we're going to talk + + + align:start position:0% +continue that but we're going to talk +more about the actual populations of + + align:start position:0% +more about the actual populations of + + + align:start position:0% +more about the actual populations of +neurons in your head that are involved + + align:start position:0% +neurons in your head that are involved + + + align:start position:0% +neurons in your head that are involved +in doing this and we'll talk about a + + align:start position:0% +in doing this and we'll talk about a + + + align:start position:0% +in doing this and we'll talk about a +particular aspect of the problem of + + align:start position:0% +particular aspect of the problem of + + + align:start position:0% +particular aspect of the problem of +navigation which is called reorientation + + align:start position:0% +navigation which is called reorientation + + + align:start position:0% +navigation which is called reorientation +that's what happens when you lose your + + align:start position:0% +that's what happens when you lose your + + + align:start position:0% +that's what happens when you lose your +bearings and you need to figure out + + align:start position:0% +bearings and you need to figure out + + + align:start position:0% +bearings and you need to figure out +where you are again reset your + + align:start position:0% +where you are again reset your + + + align:start position:0% +where you are again reset your +internal + + align:start position:0% +internal + + + align:start position:0% +internal +map of yours of where you are + + align:start position:0% +map of yours of where you are + + + align:start position:0% +map of yours of where you are +and then we'll talk about the idea that + + align:start position:0% +and then we'll talk about the idea that + + + align:start position:0% +and then we'll talk about the idea that +this whole system for navigation cool as + + align:start position:0% +this whole system for navigation cool as + + + align:start position:0% +this whole system for navigation cool as +it is and fascinating as navigation + + align:start position:0% +it is and fascinating as navigation + + + align:start position:0% +it is and fascinating as navigation +itself is is even more interesting + + align:start position:0% +itself is is even more interesting + + + align:start position:0% +itself is is even more interesting +because there's increasing evidence that + + align:start position:0% +because there's increasing evidence that + + + align:start position:0% +because there's increasing evidence that +we use that same system for lots of + + align:start position:0% +we use that same system for lots of + + + align:start position:0% +we use that same system for lots of +other aspects of high-level cognition + + align:start position:0% +other aspects of high-level cognition + + + align:start position:0% +other aspects of high-level cognition +that have nothing to do with space per + + align:start position:0% +that have nothing to do with space per + + + align:start position:0% +that have nothing to do with space per +se + + align:start position:0% +se + + + align:start position:0% +se +okay that's the and then we'll have a + + align:start position:0% +okay that's the and then we'll have a + + + align:start position:0% +okay that's the and then we'll have a +quiz short quiz + + align:start position:0% +quiz short quiz + + + align:start position:0% +quiz short quiz +that's the agenda here we go so the + + align:start position:0% +that's the agenda here we go so the + + + align:start position:0% +that's the agenda here we go so the +basic problems of navigation are one + + align:start position:0% +basic problems of navigation are one + + + align:start position:0% +basic problems of navigation are one +where am i + + align:start position:0% +where am i + + + align:start position:0% +where am i +and two how do i get from here to + + align:start position:0% +and two how do i get from here to + + + align:start position:0% +and two how do i get from here to +wherever else i want to go + + align:start position:0% +wherever else i want to go + + + align:start position:0% +wherever else i want to go +and as i mentioned last time we can + + align:start position:0% +and as i mentioned last time we can + + + align:start position:0% +and as i mentioned last time we can +break down each of these into a bunch of + + align:start position:0% +break down each of these into a bunch of + + + align:start position:0% +break down each of these into a bunch of +different components and facets of that + + align:start position:0% +different components and facets of that + + + align:start position:0% +different components and facets of that +question so when we want to know where + + align:start position:0% +question so when we want to know where + + + align:start position:0% +question so when we want to know where +we are + + align:start position:0% +we are + + + align:start position:0% +we are +that can that can involve recognizing a + + align:start position:0% +that can that can involve recognizing a + + + align:start position:0% +that can that can involve recognizing a +familiar location so if you see a + + align:start position:0% +familiar location so if you see a + + + align:start position:0% +familiar location so if you see a +photograph or you were plunked down + + align:start position:0% +photograph or you were plunked down + + + align:start position:0% +photograph or you were plunked down +spontaneously in an environment + + align:start position:0% +spontaneously in an environment + + + align:start position:0% +spontaneously in an environment +someplace you know you would visually + + align:start position:0% +someplace you know you would visually + + + align:start position:0% +someplace you know you would visually +recognize it and that would be one way + + align:start position:0% +recognize it and that would be one way + + + align:start position:0% +recognize it and that would be one way +to know where you were like this is my + + align:start position:0% +to know where you were like this is my + + + align:start position:0% +to know where you were like this is my +living room + + align:start position:0% +living room + + + align:start position:0% +living room +even if that location is unfamiliar and + + align:start position:0% +even if that location is unfamiliar and + + + align:start position:0% +even if that location is unfamiliar and +you're plunked down at random you still + + align:start position:0% +you're plunked down at random you still + + + align:start position:0% +you're plunked down at random you still +have some idea of what kind of a place + + align:start position:0% +have some idea of what kind of a place + + + align:start position:0% +have some idea of what kind of a place +this is am i in a natural environment an + + align:start position:0% +this is am i in a natural environment an + + + align:start position:0% +this is am i in a natural environment an +urban environment am i inside am i + + align:start position:0% +urban environment am i inside am i + + + align:start position:0% +urban environment am i inside am i +outside et cetera + + align:start position:0% +outside et cetera + + + align:start position:0% +outside et cetera +and finally you had you would have some + + align:start position:0% +and finally you had you would have some + + + align:start position:0% +and finally you had you would have some +sense of where you are with respect to + + align:start position:0% +sense of where you are with respect to + + + align:start position:0% +sense of where you are with respect to +the immediate bounding + + align:start position:0% +the immediate bounding + + + align:start position:0% +the immediate bounding +structures in your immediate environment + + align:start position:0% +structures in your immediate environment + + + align:start position:0% +structures in your immediate environment +like for example where you are in this + + align:start position:0% +like for example where you are in this + + + align:start position:0% +like for example where you are in this +room like as i'm talking to you right + + align:start position:0% +room like as i'm talking to you right + + + align:start position:0% +room like as i'm talking to you right +now i'm aware that there's a wall behind + + align:start position:0% +now i'm aware that there's a wall behind + + + align:start position:0% +now i'm aware that there's a wall behind +me right + + align:start position:0% +me right + + + align:start position:0% +me right +that kind of immediate + + align:start position:0% +that kind of immediate + + + align:start position:0% +that kind of immediate +spatial + + align:start position:0% +spatial + + + align:start position:0% +spatial +location + + align:start position:0% +location + + + align:start position:0% +location +in terms of questions that arise when we + + align:start position:0% +in terms of questions that arise when we + + + align:start position:0% +in terms of questions that arise when we +have to figure out how do we get from + + align:start position:0% +have to figure out how do we get from + + + align:start position:0% +have to figure out how do we get from +here to wherever else we want to go + + align:start position:0% + + + + align:start position:0% + +if you can directly see or hear your + + align:start position:0% +if you can directly see or hear your + + + align:start position:0% +if you can directly see or hear your +destination then you have the simplest + + align:start position:0% +destination then you have the simplest + + + align:start position:0% +destination then you have the simplest +possible kind of navigation strategy you + + align:start position:0% +possible kind of navigation strategy you + + + align:start position:0% +possible kind of navigation strategy you +just go toward that thing okay that's + + align:start position:0% +just go toward that thing okay that's + + + align:start position:0% +just go toward that thing okay that's +called beaconing and it's like the + + align:start position:0% +called beaconing and it's like the + + + align:start position:0% +called beaconing and it's like the +minimalist case works great if you can + + align:start position:0% +minimalist case works great if you can + + + align:start position:0% +minimalist case works great if you can +see or hear your destination + + align:start position:0% +see or hear your destination + + + align:start position:0% +see or hear your destination +but when you can't + + align:start position:0% +but when you can't + + + align:start position:0% +but when you can't +you need to know + + align:start position:0% +you need to know + + + align:start position:0% +you need to know +where am i in this in my broader + + align:start position:0% +where am i in this in my broader + + + align:start position:0% +where am i in this in my broader +understanding of the layout of my + + align:start position:0% +understanding of the layout of my + + + align:start position:0% +understanding of the layout of my +environment and where is my goal and for + + align:start position:0% +environment and where is my goal and for + + + align:start position:0% +environment and where is my goal and for +that you need a mental map of your + + align:start position:0% +that you need a mental map of your + + + align:start position:0% +that you need a mental map of your +environment and we'll talk more about + + align:start position:0% +environment and we'll talk more about + + + align:start position:0% +environment and we'll talk more about +that today that's why it's in red + + align:start position:0% +that today that's why it's in red + + + align:start position:0% +that today that's why it's in red +you also need to know your current + + align:start position:0% +you also need to know your current + + + align:start position:0% +you also need to know your current +heading in that environment it's not + + align:start position:0% +heading in that environment it's not + + + align:start position:0% +heading in that environment it's not +enough to know in my map of the world i + + align:start position:0% +enough to know in my map of the world i + + + align:start position:0% +enough to know in my map of the world i +am here with a dot you need to know + + align:start position:0% +am here with a dot you need to know + + + align:start position:0% +am here with a dot you need to know +which way you're facing in that map of + + align:start position:0% +which way you're facing in that map of + + + align:start position:0% +which way you're facing in that map of +the world in order to plan your + + align:start position:0% +the world in order to plan your + + + align:start position:0% +the world in order to plan your +navigation we'll talk about that too + + align:start position:0% +navigation we'll talk about that too + + + align:start position:0% +navigation we'll talk about that too +we also need to know what routes are + + align:start position:0% +we also need to know what routes are + + + align:start position:0% +we also need to know what routes are +possible from here so i may want to go + + align:start position:0% +possible from here so i may want to go + + + align:start position:0% +possible from here so i may want to go +over to stata and get a cup of coffee + + align:start position:0% +over to stata and get a cup of coffee + + + align:start position:0% +over to stata and get a cup of coffee +but i can't go this way i got to go + + align:start position:0% +but i can't go this way i got to go + + + align:start position:0% +but i can't go this way i got to go +around because i can't go through that + + align:start position:0% +around because i can't go through that + + + align:start position:0% +around because i can't go through that +glass okay and so finally that this + + align:start position:0% +glass okay and so finally that this + + + align:start position:0% +glass okay and so finally that this +whole magnificent system that enables us + + align:start position:0% +whole magnificent system that enables us + + + align:start position:0% +whole magnificent system that enables us +to process all this stuff works pretty + + align:start position:0% +to process all this stuff works pretty + + + align:start position:0% +to process all this stuff works pretty +impressively but every once in a while + + align:start position:0% +impressively but every once in a while + + + align:start position:0% +impressively but every once in a while +something will go wrong and it will you + + align:start position:0% +something will go wrong and it will you + + + align:start position:0% +something will go wrong and it will you +know get the wrong signal and then we're + + align:start position:0% +know get the wrong signal and then we're + + + align:start position:0% +know get the wrong signal and then we're +lost and so then we need a way to regain + + align:start position:0% +lost and so then we need a way to regain + + + align:start position:0% +lost and so then we need a way to regain +our bearings and we'll talk about that + + align:start position:0% +our bearings and we'll talk about that + + + align:start position:0% +our bearings and we'll talk about that +too + + align:start position:0% +too + + + align:start position:0% +too +um so + + align:start position:0% +um so + + + align:start position:0% +um so +last time i talked about a bunch of + + align:start position:0% +last time i talked about a bunch of + + + align:start position:0% +last time i talked about a bunch of +brain regions that are implicated in + + align:start position:0% +brain regions that are implicated in + + + align:start position:0% +brain regions that are implicated in +perceiving scenes and in navigation + + align:start position:0% +perceiving scenes and in navigation + + + align:start position:0% +perceiving scenes and in navigation +we talked about the perihipic apple + + align:start position:0% +we talked about the perihipic apple + + + align:start position:0% +we talked about the perihipic apple +place area right here and this region + + align:start position:0% +place area right here and this region + + + align:start position:0% +place area right here and this region +over here formerly known as tos now + + align:start position:0% +over here formerly known as tos now + + + align:start position:0% +over here formerly known as tos now +known as opa you don't need to remember + + align:start position:0% +known as opa you don't need to remember + + + align:start position:0% +known as opa you don't need to remember +all that it's the bit that's out on the + + align:start position:0% +all that it's the bit that's out on the + + + align:start position:0% +all that it's the bit that's out on the +lateral surface that we can zap because + + align:start position:0% +lateral surface that we can zap because + + + align:start position:0% +lateral surface that we can zap because +it's out there + + align:start position:0% +it's out there + + + align:start position:0% +it's out there +and both of those regions seem to be + + align:start position:0% +and both of those regions seem to be + + + align:start position:0% +and both of those regions seem to be +involved broadly in perceiving the shape + + align:start position:0% +involved broadly in perceiving the shape + + + align:start position:0% +involved broadly in perceiving the shape +of space around you + + align:start position:0% +of space around you + + + align:start position:0% +of space around you +we also talked a bit about retrosplenial + + align:start position:0% +we also talked a bit about retrosplenial + + + align:start position:0% +we also talked a bit about retrosplenial +cortex that region that's hiding in the + + align:start position:0% +cortex that region that's hiding in the + + + align:start position:0% +cortex that region that's hiding in the +sulcus here that you can see better when + + align:start position:0% +sulcus here that you can see better when + + + align:start position:0% +sulcus here that you can see better when +you mathematically unfold the sulcus + + align:start position:0% +you mathematically unfold the sulcus + + + align:start position:0% +you mathematically unfold the sulcus +there it is responds more to scenes and + + align:start position:0% +there it is responds more to scenes and + + + align:start position:0% +there it is responds more to scenes and +objects and that region seems to be + + align:start position:0% +objects and that region seems to be + + + align:start position:0% +objects and that region seems to be +involved in something like getting your + + align:start position:0% +involved in something like getting your + + + align:start position:0% +involved in something like getting your +bearings that is the location and + + align:start position:0% +bearings that is the location and + + + align:start position:0% +bearings that is the location and +orientation of where you are + + align:start position:0% +orientation of where you are + + + align:start position:0% +orientation of where you are +with respect to your cognitive map and + + align:start position:0% +with respect to your cognitive map and + + + align:start position:0% +with respect to your cognitive map and +environment okay so to make that a + + align:start position:0% +environment okay so to make that a + + + align:start position:0% +environment okay so to make that a +little more vivid i gave you one + + align:start position:0% +little more vivid i gave you one + + + align:start position:0% +little more vivid i gave you one +description of a patient before but + + align:start position:0% +description of a patient before but + + + align:start position:0% +description of a patient before but +here's from another study + + align:start position:0% +here's from another study + + + align:start position:0% +here's from another study +patients with damage to retrosplenial + + align:start position:0% +patients with damage to retrosplenial + + + align:start position:0% +patients with damage to retrosplenial +cortex + + align:start position:0% +cortex + + + align:start position:0% +cortex +so here's from a recent article in every + + align:start position:0% +so here's from a recent article in every + + + align:start position:0% +so here's from a recent article in every +case the patient with this damage was + + align:start position:0% +case the patient with this damage was + + + align:start position:0% +case the patient with this damage was +able to recognize landmarks in their + + align:start position:0% +able to recognize landmarks in their + + + align:start position:0% +able to recognize landmarks in their +neighborhoods and retained a sense of + + align:start position:0% +neighborhoods and retained a sense of + + + align:start position:0% +neighborhoods and retained a sense of +familiarity i know that place that's the + + align:start position:0% +familiarity i know that place that's the + + + align:start position:0% +familiarity i know that place that's the +coffee shop five blocks from my house + + align:start position:0% +coffee shop five blocks from my house + + + align:start position:0% +coffee shop five blocks from my house +right but despite that + + align:start position:0% +right but despite that + + + align:start position:0% +right but despite that +none of those patients were able to find + + align:start position:0% +none of those patients were able to find + + + align:start position:0% +none of those patients were able to find +their way in familiar environments and + + align:start position:0% +their way in familiar environments and + + + align:start position:0% +their way in familiar environments and +all but one were unable to learn new + + align:start position:0% +all but one were unable to learn new + + + align:start position:0% +all but one were unable to learn new +routes so they can recognize visual the + + align:start position:0% +routes so they can recognize visual the + + + align:start position:0% +routes so they can recognize visual the +visual form of a particular place but + + align:start position:0% +visual form of a particular place but + + + align:start position:0% +visual form of a particular place but +they don't know how to relate that to + + align:start position:0% +they don't know how to relate that to + + + align:start position:0% +they don't know how to relate that to +their cognitive map of the world and + + align:start position:0% +their cognitive map of the world and + + + align:start position:0% +their cognitive map of the world and +their therefore plan a route from there + + align:start position:0% +their therefore plan a route from there + + + align:start position:0% +their therefore plan a route from there +okay + + align:start position:0% +okay + + + align:start position:0% +okay +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so um the part that i only alluded to at + + align:start position:0% +so um the part that i only alluded to at + + + align:start position:0% +so um the part that i only alluded to at +the end yes question + + align:start position:0% +the end yes question + + + align:start position:0% +the end yes question +okay is the + + align:start position:0% +okay is the + + + align:start position:0% +okay is the +retros cortex home to the clock on the + + align:start position:0% +retros cortex home to the clock on the + + + align:start position:0% +retros cortex home to the clock on the +cops or is it + + align:start position:0% +cops or is it + + + align:start position:0% +cops or is it +great question we don't exactly know the + + align:start position:0% +great question we don't exactly know the + + + align:start position:0% +great question we don't exactly know the +typical story is that the home of the + + align:start position:0% +typical story is that the home of the + + + align:start position:0% +typical story is that the home of the +cognitive map is the hippocampus which + + align:start position:0% +cognitive map is the hippocampus which + + + align:start position:0% +cognitive map is the hippocampus which +we're about to talk talk about next for + + align:start position:0% +we're about to talk talk about next for + + + align:start position:0% +we're about to talk talk about next for +reasons i will tell you but all of this + + align:start position:0% +reasons i will tell you but all of this + + + align:start position:0% +reasons i will tell you but all of this +is kind of this is a very active area of + + align:start position:0% +is kind of this is a very active area of + + + align:start position:0% +is kind of this is a very active area of +research it kills me every time i do + + align:start position:0% +research it kills me every time i do + + + align:start position:0% +research it kills me every time i do +these lectures i look at my old notes + + align:start position:0% +these lectures i look at my old notes + + + align:start position:0% +these lectures i look at my old notes +and i think here are these 10 other + + align:start position:0% +and i think here are these 10 other + + + align:start position:0% +and i think here are these 10 other +awesome studies and then i try to fit + + align:start position:0% +awesome studies and then i try to fit + + + align:start position:0% +awesome studies and then i try to fit +them in and then they just don't fit so + + align:start position:0% +them in and then they just don't fit so + + + align:start position:0% +them in and then they just don't fit so +actually one question i want to ask you + + align:start position:0% +actually one question i want to ask you + + + align:start position:0% +actually one question i want to ask you +guys after this lecture is should i in + + align:start position:0% +guys after this lecture is should i in + + + align:start position:0% +guys after this lecture is should i in +future either later in this course or in + + align:start position:0% +future either later in this course or in + + + align:start position:0% +future either later in this course or in +future courses allocate even more time + + align:start position:0% +future courses allocate even more time + + + align:start position:0% +future courses allocate even more time +or do you guys feel like okay enough + + align:start position:0% +or do you guys feel like okay enough + + + align:start position:0% +or do you guys feel like okay enough +already with navigation but i just think + + align:start position:0% +already with navigation but i just think + + + align:start position:0% +already with navigation but i just think +it's the coolest system so there's lots + + align:start position:0% +it's the coolest system so there's lots + + + align:start position:0% +it's the coolest system so there's lots +of work + + align:start position:0% +of work + + + align:start position:0% +of work +exactly trying to answer that kind of + + align:start position:0% +exactly trying to answer that kind of + + + align:start position:0% +exactly trying to answer that kind of +question and i'll give you + + align:start position:0% +question and i'll give you + + + align:start position:0% +question and i'll give you +a current snapshot of the approximate + + align:start position:0% +a current snapshot of the approximate + + + align:start position:0% +a current snapshot of the approximate +state but all of this is in flux and + + align:start position:0% +state but all of this is in flux and + + + align:start position:0% +state but all of this is in flux and +very much actively investigated + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so + + align:start position:0% +so + + + align:start position:0% +so +cognitive map what do we mean by that + + align:start position:0% +cognitive map what do we mean by that + + + align:start position:0% +cognitive map what do we mean by that +just to remind you of this classic study + + align:start position:0% +just to remind you of this classic study + + + align:start position:0% +just to remind you of this classic study +from the 1940s in rats where the rat + + align:start position:0% +from the 1940s in rats where the rat + + + align:start position:0% +from the 1940s in rats where the rat +when they learned this route and then + + align:start position:0% +when they learned this route and then + + + align:start position:0% +when they learned this route and then +went up here and found their gold block + + align:start position:0% +went up here and found their gold block + + + align:start position:0% +went up here and found their gold block +the rat immediately comes out and goes + + align:start position:0% +the rat immediately comes out and goes + + + align:start position:0% +the rat immediately comes out and goes +straight toward the goal telling you + + align:start position:0% +straight toward the goal telling you + + + align:start position:0% +straight toward the goal telling you +they've learned something much more + + align:start position:0% +they've learned something much more + + + align:start position:0% +they've learned something much more +interesting than the series of left and + + align:start position:0% +interesting than the series of left and + + + align:start position:0% +interesting than the series of left and +right turns to get to the goal they must + + align:start position:0% +right turns to get to the goal they must + + + align:start position:0% +right turns to get to the goal they must +have done something much more like + + align:start position:0% +have done something much more like + + + align:start position:0% +have done something much more like +actually learned the layout of space and + + align:start position:0% +actually learned the layout of space and + + + align:start position:0% +actually learned the layout of space and +the relative position of that goal so + + align:start position:0% +the relative position of that goal so + + + align:start position:0% +the relative position of that goal so +they could come up with a new vector to + + align:start position:0% +they could come up with a new vector to + + + align:start position:0% +they could come up with a new vector to +get there when the original route was + + align:start position:0% +get there when the original route was + + + align:start position:0% +get there when the original route was +blocked + + align:start position:0% +blocked + + + align:start position:0% +blocked +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and you guys can do this too right when + + align:start position:0% +and you guys can do this too right when + + + align:start position:0% +and you guys can do this too right when +your root is blocked you come up with a + + align:start position:0% +your root is blocked you come up with a + + + align:start position:0% +your root is blocked you come up with a +novel root right + + align:start position:0% +novel root right + + + align:start position:0% +novel root right +uh and you do that by having some + + align:start position:0% +uh and you do that by having some + + + align:start position:0% +uh and you do that by having some +knowledge of your environment something + + align:start position:0% +knowledge of your environment something + + + align:start position:0% +knowledge of your environment something +tantamount to that in your head + + align:start position:0% +tantamount to that in your head + + + align:start position:0% +tantamount to that in your head +some version of that + + align:start position:0% +some version of that + + + align:start position:0% +some version of that +and further you know where you are in + + align:start position:0% +and further you know where you are in + + + align:start position:0% +and further you know where you are in +that map like right now you know where + + align:start position:0% +that map like right now you know where + + + align:start position:0% +that map like right now you know where +you are + + align:start position:0% +you are + + + align:start position:0% +you are +okay + + align:start position:0% +okay + + + align:start position:0% +okay +now here's the cool thing + + align:start position:0% +now here's the cool thing + + + align:start position:0% +now here's the cool thing +specific neurons in your hippocampus + + align:start position:0% +specific neurons in your hippocampus + + + align:start position:0% +specific neurons in your hippocampus +right now are firing telling you that + + align:start position:0% +right now are firing telling you that + + + align:start position:0% +right now are firing telling you that +you are right there + + align:start position:0% +you are right there + + + align:start position:0% +you are right there +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so these neurons are called place cells + + align:start position:0% +so these neurons are called place cells + + + align:start position:0% +so these neurons are called place cells +and this is what they do okay so i'll be + + align:start position:0% +and this is what they do okay so i'll be + + + align:start position:0% +and this is what they do okay so i'll be +a place cell or what rather what i'll do + + align:start position:0% +a place cell or what rather what i'll do + + + align:start position:0% +a place cell or what rather what i'll do +is i will act out the activity of a + + align:start position:0% +is i will act out the activity of a + + + align:start position:0% +is i will act out the activity of a +place cell by a series of clicks i will + + align:start position:0% +place cell by a series of clicks i will + + + align:start position:0% +place cell by a series of clicks i will +make as i walk around so imagine there's + + align:start position:0% +make as i walk around so imagine there's + + + align:start position:0% +make as i walk around so imagine there's +an electrode in my hippocampus and you + + align:start position:0% +an electrode in my hippocampus and you + + + align:start position:0% +an electrode in my hippocampus and you +are hearing the activity of a single + + align:start position:0% +are hearing the activity of a single + + + align:start position:0% +are hearing the activity of a single +neuron in my hippocampus as i walk + + align:start position:0% +neuron in my hippocampus as i walk + + + align:start position:0% +neuron in my hippocampus as i walk +around and here's what it would do + + align:start position:0% +around and here's what it would do + + + align:start position:0% +around and here's what it would do +you'd hear background firing so it's + + align:start position:0% +you'd hear background firing so it's + + + align:start position:0% +you'd hear background firing so it's +going to go click click + + align:start position:0% +going to go click click + + + align:start position:0% +going to go click click +click click click noisy background + + align:start position:0% +click click click noisy background + + + align:start position:0% +click click click noisy background +finding firing click click + + align:start position:0% +finding firing click click + + + align:start position:0% +finding firing click click +click click + + align:start position:0% +click click + + + align:start position:0% +click click +click click click click click + + align:start position:0% +click click click click click + + + align:start position:0% +click click click click click +click click click click click click + + align:start position:0% +click click click click click click + + + align:start position:0% +click click click click click click +click click click click click + + align:start position:0% +click click click click click + + + align:start position:0% +click click click click click +click + + align:start position:0% +click + + + align:start position:0% +click +click click okay i'm not going to go + + align:start position:0% +click click okay i'm not going to go + + + align:start position:0% +click click okay i'm not going to go +down there click click click click click + + align:start position:0% +down there click click click click click + + + align:start position:0% +down there click click click click click +click look click click click click click + + align:start position:0% +click look click click click click click + + + align:start position:0% +click look click click click click click +click click click + + align:start position:0% +click click click + + + align:start position:0% +click click click +click click click click + + align:start position:0% +click click click click + + + align:start position:0% +click click click click +click click click + + align:start position:0% +click click click + + + align:start position:0% +click click click +so that's one neuron that fires only + + align:start position:0% +so that's one neuron that fires only + + + align:start position:0% +so that's one neuron that fires only +when i'm right over there that place + + align:start position:0% +when i'm right over there that place + + + align:start position:0% +when i'm right over there that place +it's not where i'm facing over there + + align:start position:0% +it's not where i'm facing over there + + + align:start position:0% +it's not where i'm facing over there +it's not what i'm looking at + + align:start position:0% +it's not what i'm looking at + + + align:start position:0% +it's not what i'm looking at +particularly it's when i'm right there + + align:start position:0% +particularly it's when i'm right there + + + align:start position:0% +particularly it's when i'm right there +okay that's a place cell + + align:start position:0% +okay that's a place cell + + + align:start position:0% +okay that's a place cell +and so there's lots of place cells in + + align:start position:0% +and so there's lots of place cells in + + + align:start position:0% +and so there's lots of place cells in +your hippocampus + + align:start position:0% +your hippocampus + + + align:start position:0% +your hippocampus +that do that and they do it for + + align:start position:0% +that do that and they do it for + + + align:start position:0% +that do that and they do it for +different locations in your environment + + align:start position:0% +different locations in your environment + + + align:start position:0% +different locations in your environment +and all of this was first worked out of + + align:start position:0% +and all of this was first worked out of + + + align:start position:0% +and all of this was first worked out of +course in rodents who were running + + align:start position:0% +course in rodents who were running + + + align:start position:0% +course in rodents who were running +around who had electrodes in their + + align:start position:0% +around who had electrodes in their + + + align:start position:0% +around who had electrodes in their +hippocampus but where those electrodes + + align:start position:0% +hippocampus but where those electrodes + + + align:start position:0% +hippocampus but where those electrodes +were connected with a loose tether so + + align:start position:0% +were connected with a loose tether so + + + align:start position:0% +were connected with a loose tether so +that the rodent could move around in + + align:start position:0% +that the rodent could move around in + + + align:start position:0% +that the rodent could move around in +their environment while recording from + + align:start position:0% +their environment while recording from + + + align:start position:0% +their environment while recording from +individual neurons in the campus okay so + + align:start position:0% +individual neurons in the campus okay so + + + align:start position:0% +individual neurons in the campus okay so +that's the setup + + align:start position:0% +that's the setup + + + align:start position:0% +that's the setup +and so i'm going to show you a movie of + + align:start position:0% +and so i'm going to show you a movie of + + + align:start position:0% +and so i'm going to show you a movie of +an aerial view + + align:start position:0% +an aerial view + + + align:start position:0% +an aerial view +of a rodent + + align:start position:0% +of a rodent + + + align:start position:0% +of a rodent +moving around + + align:start position:0% +moving around + + + align:start position:0% +moving around +a rat moving around in its environment + + align:start position:0% +a rat moving around in its environment + + + align:start position:0% +a rat moving around in its environment +can you see the little rat there + + align:start position:0% +can you see the little rat there + + + align:start position:0% +can you see the little rat there +um and what's happening is this um video + + align:start position:0% +um and what's happening is this um video + + + align:start position:0% +um and what's happening is this um video +is tracing out the rat's path with the + + align:start position:0% +is tracing out the rat's path with the + + + align:start position:0% +is tracing out the rat's path with the +light gray and every time that it's + + align:start position:0% +light gray and every time that it's + + + align:start position:0% +light gray and every time that it's +recording from one neuron every time + + align:start position:0% +recording from one neuron every time + + + align:start position:0% +recording from one neuron every time +that neuron fires it makes a red dot and + + align:start position:0% +that neuron fires it makes a red dot and + + + align:start position:0% +that neuron fires it makes a red dot and +so this is obviously sped up but as the + + align:start position:0% +so this is obviously sped up but as the + + + align:start position:0% +so this is obviously sped up but as the +rat moves around in his environment you + + align:start position:0% +rat moves around in his environment you + + + align:start position:0% +rat moves around in his environment you +see an accumulation like more firing + + align:start position:0% +see an accumulation like more firing + + + align:start position:0% +see an accumulation like more firing +when the rat is right there + + align:start position:0% +when the rat is right there + + + align:start position:0% +when the rat is right there +it's not which direction the rat is + + align:start position:0% +it's not which direction the rat is + + + align:start position:0% +it's not which direction the rat is +going through when he goes there just + + align:start position:0% +going through when he goes there just + + + align:start position:0% +going through when he goes there just +basically whenever he passes through + + align:start position:0% +basically whenever he passes through + + + align:start position:0% +basically whenever he passes through +that in any direction + + align:start position:0% +that in any direction + + + align:start position:0% +that in any direction +neurons fire more than anywhere else and + + align:start position:0% +neurons fire more than anywhere else and + + + align:start position:0% +neurons fire more than anywhere else and +then if we take that and blur it as + + align:start position:0% +then if we take that and blur it as + + + align:start position:0% +then if we take that and blur it as +scientists like to do to make nice + + align:start position:0% +scientists like to do to make nice + + + align:start position:0% +scientists like to do to make nice +idealized pictures + + align:start position:0% +idealized pictures + + + align:start position:0% +idealized pictures +that is the place cell for that neuron + + align:start position:0% +that is the place cell for that neuron + + + align:start position:0% +that is the place cell for that neuron +that is the place in space + + align:start position:0% +that is the place in space + + + align:start position:0% +that is the place in space +that that animal has to be to make that + + align:start position:0% +that that animal has to be to make that + + + align:start position:0% +that that animal has to be to make that +neuron fire + + align:start position:0% +neuron fire + + + align:start position:0% +neuron fire +yeah question is it one dimension + + align:start position:0% +yeah question is it one dimension + + + align:start position:0% +yeah question is it one dimension +i mean can multiple cases be mapped to + + align:start position:0% +i mean can multiple cases be mapped to + + + align:start position:0% +i mean can multiple cases be mapped to +save your home um that's complicated + + align:start position:0% +save your home um that's complicated + + + align:start position:0% +save your home um that's complicated +in an immediate environment like this + + align:start position:0% +in an immediate environment like this + + + align:start position:0% +in an immediate environment like this +generally not okay i'll show you some + + align:start position:0% +generally not okay i'll show you some + + + align:start position:0% +generally not okay i'll show you some +examples in a moment + + align:start position:0% +examples in a moment + + + align:start position:0% +examples in a moment +it's more complicated if you follow that + + align:start position:0% +it's more complicated if you follow that + + + align:start position:0% +it's more complicated if you follow that +cell when the animal moves to new + + align:start position:0% +cell when the animal moves to new + + + align:start position:0% +cell when the animal moves to new +locations so let me say a few more + + align:start position:0% +locations so let me say a few more + + + align:start position:0% +locations so let me say a few more +things and then i'll then if it's not + + align:start position:0% +things and then i'll then if it's not + + + align:start position:0% +things and then i'll then if it's not +clear i'll take questions oops i'm going + + align:start position:0% +clear i'll take questions oops i'm going + + + align:start position:0% +clear i'll take questions oops i'm going +to see it again + + align:start position:0% +to see it again + + + align:start position:0% +to see it again +okay right so so in answer to josh's + + align:start position:0% +okay right so so in answer to josh's + + + align:start position:0% +okay right so so in answer to josh's +question here are a bunch of place cells + + align:start position:0% +question here are a bunch of place cells + + + align:start position:0% +question here are a bunch of place cells +from a rodent exploring the same + + align:start position:0% +from a rodent exploring the same + + + align:start position:0% +from a rodent exploring the same +environment so you might say well + + align:start position:0% +environment so you might say well + + + align:start position:0% +environment so you might say well +there's like a hot spot here and a + + align:start position:0% +there's like a hot spot here and a + + + align:start position:0% +there's like a hot spot here and a +little sub one there but in general most + + align:start position:0% +little sub one there but in general most + + + align:start position:0% +little sub one there but in general most +of these cells respond with a hot spot + + align:start position:0% +of these cells respond with a hot spot + + + align:start position:0% +of these cells respond with a hot spot +in a particular single location in this + + align:start position:0% +in a particular single location in this + + + align:start position:0% +in a particular single location in this +particular environment + + align:start position:0% +particular environment + + + align:start position:0% +particular environment +okay did you have a different question + + align:start position:0% +okay did you have a different question + + + align:start position:0% +okay did you have a different question +about that yes + + align:start position:0% +about that yes + + + align:start position:0% +about that yes +so + + align:start position:0% +so + + + align:start position:0% +so +that all depends on the wrath + + align:start position:0% +that all depends on the wrath + + + align:start position:0% +that all depends on the wrath +um + + align:start position:0% +um + + + align:start position:0% +um +the unconscious of the fact whether it's + + align:start position:0% +the unconscious of the fact whether it's + + + align:start position:0% +the unconscious of the fact whether it's +in that place + + align:start position:0% +in that place + + + align:start position:0% +in that place +if the rat was anesthetized or if he was + + align:start position:0% +if the rat was anesthetized or if he was + + + align:start position:0% +if the rat was anesthetized or if he was +you know blindfolded and you passively + + align:start position:0% +you know blindfolded and you passively + + + align:start position:0% +you know blindfolded and you passively +moved him around in that space and he + + align:start position:0% +moved him around in that space and he + + + align:start position:0% +moved him around in that space and he +had no idea no way to tell where he was + + align:start position:0% +had no idea no way to tell where he was + + + align:start position:0% +had no idea no way to tell where he was +that wouldn't work however if the rat + + align:start position:0% +that wouldn't work however if the rat + + + align:start position:0% +that wouldn't work however if the rat +knows the environment + + align:start position:0% +knows the environment + + + align:start position:0% +knows the environment +and then you do this in a darkened room + + align:start position:0% +and then you do this in a darkened room + + + align:start position:0% +and then you do this in a darkened room +where he's actively locomoting around + + align:start position:0% +where he's actively locomoting around + + + align:start position:0% +where he's actively locomoting around +these things will still work pretty well + + align:start position:0% +these things will still work pretty well + + + align:start position:0% +these things will still work pretty well +because rats are very good at keeping + + align:start position:0% +because rats are very good at keeping + + + align:start position:0% +because rats are very good at keeping +track of where they are + + align:start position:0% +track of where they are + + + align:start position:0% +track of where they are +even without visual cues if they know + + align:start position:0% +even without visual cues if they know + + + align:start position:0% +even without visual cues if they know +the environment they'll have other cues + + align:start position:0% +the environment they'll have other cues + + + align:start position:0% +the environment they'll have other cues +like tactile cues and like they will + + align:start position:0% +like tactile cues and like they will + + + align:start position:0% +like tactile cues and like they will +know how far they went in each direction + + align:start position:0% +know how far they went in each direction + + + align:start position:0% +know how far they went in each direction +remember i talked briefly about the + + align:start position:0% +remember i talked briefly about the + + + align:start position:0% +remember i talked briefly about the +tunisian ants doing dead reckoning + + align:start position:0% +tunisian ants doing dead reckoning + + + align:start position:0% +tunisian ants doing dead reckoning +right keeping track of their vector and + + align:start position:0% +right keeping track of their vector and + + + align:start position:0% +right keeping track of their vector and +speed at each moment and integrating the + + align:start position:0% +speed at each moment and integrating the + + + align:start position:0% +speed at each moment and integrating the +whole thing to know where they are + + align:start position:0% +whole thing to know where they are + + + align:start position:0% +whole thing to know where they are +that's called dead reckoning rats are + + align:start position:0% +that's called dead reckoning rats are + + + align:start position:0% +that's called dead reckoning rats are +pretty good at that too + + align:start position:0% +pretty good at that too + + + align:start position:0% +pretty good at that too +another question over here yeah + + align:start position:0% +another question over here yeah + + + align:start position:0% +another question over here yeah +um the police officers do they have like + + align:start position:0% +um the police officers do they have like + + + align:start position:0% +um the police officers do they have like +uh look at math as well like how like + + align:start position:0% +uh look at math as well like how like + + + align:start position:0% +uh look at math as well like how like +we'll get there great question we'll get + + align:start position:0% +we'll get there great question we'll get + + + align:start position:0% +we'll get there great question we'll get +there + + align:start position:0% +there + + + align:start position:0% +there +i'll just give you the answer no they + + align:start position:0% +i'll just give you the answer no they + + + align:start position:0% +i'll just give you the answer no they +don't it's too bad um + + align:start position:0% +don't it's too bad um + + + align:start position:0% +don't it's too bad um +they could have they could have been all + + align:start position:0% +they could have they could have been all + + + align:start position:0% +they could have they could have been all +organized but it's actually a little + + align:start position:0% +organized but it's actually a little + + + align:start position:0% +organized but it's actually a little +complicated how would you organize them + + align:start position:0% +complicated how would you organize them + + + align:start position:0% +complicated how would you organize them +then what if you like learned more stuff + + align:start position:0% +then what if you like learned more stuff + + + align:start position:0% +then what if you like learned more stuff +off of the edge of space well like i had + + align:start position:0% +off of the edge of space well like i had + + + align:start position:0% +off of the edge of space well like i had +a whole other piece of your hippocampus + + align:start position:0% +a whole other piece of your hippocampus + + + align:start position:0% +a whole other piece of your hippocampus +i would be inconvenienced so maybe + + align:start position:0% +i would be inconvenienced so maybe + + + align:start position:0% +i would be inconvenienced so maybe +that's why it doesn't work whereas with + + align:start position:0% +that's why it doesn't work whereas with + + + align:start position:0% +that's why it doesn't work whereas with +visual space + + align:start position:0% +visual space + + + align:start position:0% +visual space +you know you're your retina topic + + align:start position:0% +you know you're your retina topic + + + align:start position:0% +you know you're your retina topic +information always stays the same we + + align:start position:0% +information always stays the same we + + + align:start position:0% +information always stays the same we +don't have to suddenly add + + align:start position:0% +don't have to suddenly add + + + align:start position:0% +don't have to suddenly add +a whole new part of retinotopic space + + align:start position:0% +a whole new part of retinotopic space + + + align:start position:0% +a whole new part of retinotopic space +thereby screwing up our retina topic + + align:start position:0% +thereby screwing up our retina topic + + + align:start position:0% +thereby screwing up our retina topic +maps in the brain i'm just making that + + align:start position:0% +maps in the brain i'm just making that + + + align:start position:0% +maps in the brain i'm just making that +up as a possible reason i don't know if + + align:start position:0% +up as a possible reason i don't know if + + + align:start position:0% +up as a possible reason i don't know if +that's why yeah what's sorry behind you + + align:start position:0% +that's why yeah what's sorry behind you + + + align:start position:0% +that's why yeah what's sorry behind you +david who what's tell me your name + + align:start position:0% +david who what's tell me your name + + + align:start position:0% +david who what's tell me your name +justin yeah right hi um so i was + + align:start position:0% +justin yeah right hi um so i was + + + align:start position:0% +justin yeah right hi um so i was +wondering like if you're in a smaller + + align:start position:0% +wondering like if you're in a smaller + + + align:start position:0% +wondering like if you're in a smaller +space comparatively or like a bigger + + align:start position:0% +space comparatively or like a bigger + + + align:start position:0% +space comparatively or like a bigger +space right like + + align:start position:0% +space right like + + + align:start position:0% +space right like +more areas of these specific uh place + + align:start position:0% +more areas of these specific uh place + + + align:start position:0% +more areas of these specific uh place +cells that like what they're mapping to + + align:start position:0% +cells that like what they're mapping to + + + align:start position:0% +cells that like what they're mapping to +um will they also scale up right now + + align:start position:0% +um will they also scale up right now + + + align:start position:0% +um will they also scale up right now +it's a great question i don't know the + + align:start position:0% +it's a great question i don't know the + + + align:start position:0% +it's a great question i don't know the +answer my guess is they'll scale + + align:start position:0% +answer my guess is they'll scale + + + align:start position:0% +answer my guess is they'll scale +according to the space + + align:start position:0% +according to the space + + + align:start position:0% +according to the space +right like so if if i had if that if my + + align:start position:0% +right like so if if i had if that if my + + + align:start position:0% +right like so if if i had if that if my +place my fake place cell field that i + + align:start position:0% +place my fake place cell field that i + + + align:start position:0% +place my fake place cell field that i +just acted out over there is maybe five + + align:start position:0% +just acted out over there is maybe five + + + align:start position:0% +just acted out over there is maybe five +feet across if i was then confined to a + + align:start position:0% +feet across if i was then confined to a + + + align:start position:0% +feet across if i was then confined to a +little space you'd probably have smaller + + align:start position:0% +little space you'd probably have smaller + + + align:start position:0% +little space you'd probably have smaller +ones for that space but i don't know + + align:start position:0% +ones for that space but i don't know + + + align:start position:0% +ones for that space but i don't know +let me say a little bit more about this + + align:start position:0% +let me say a little bit more about this + + + align:start position:0% +let me say a little bit more about this +so so just to catch this out the place + + align:start position:0% +so so just to catch this out the place + + + align:start position:0% +so so just to catch this out the place +field is the location in space the + + align:start position:0% +field is the location in space the + + + align:start position:0% +field is the location in space the +animal has to be to make that + + align:start position:0% +animal has to be to make that + + + align:start position:0% +animal has to be to make that +hippocampal cell fire okay + + align:start position:0% +hippocampal cell fire okay + + + align:start position:0% +hippocampal cell fire okay +so + + align:start position:0% +so + + + align:start position:0% +so +let's distinguish that from a receptive + + align:start position:0% +let's distinguish that from a receptive + + + align:start position:0% +let's distinguish that from a receptive +field in visual cortex which is a + + align:start position:0% +field in visual cortex which is a + + + align:start position:0% +field in visual cortex which is a +similar idea but a different one a + + align:start position:0% +similar idea but a different one a + + + align:start position:0% +similar idea but a different one a +receptive field in visual cortex is the + + align:start position:0% +receptive field in visual cortex is the + + + align:start position:0% +receptive field in visual cortex is the +location in the visual field where a + + align:start position:0% +location in the visual field where a + + + align:start position:0% +location in the visual field where a +stimulus has to be to make a visual + + align:start position:0% +stimulus has to be to make a visual + + + align:start position:0% +stimulus has to be to make a visual +neuron fire + + align:start position:0% +neuron fire + + + align:start position:0% +neuron fire +not where the animal itself has to be + + align:start position:0% +not where the animal itself has to be + + + align:start position:0% +not where the animal itself has to be +where the stimulus has to be okay so + + align:start position:0% +where the stimulus has to be okay so + + + align:start position:0% +where the stimulus has to be okay so +keep those ideas separate they're + + align:start position:0% +keep those ideas separate they're + + + align:start position:0% +keep those ideas separate they're +related but different + + align:start position:0% +related but different + + + align:start position:0% +related but different +okay so what about you know we and + + align:start position:0% +okay so what about you know we and + + + align:start position:0% +okay so what about you know we and +rodents tend to go around mostly on a 2d + + align:start position:0% +rodents tend to go around mostly on a 2d + + + align:start position:0% +rodents tend to go around mostly on a 2d +plane + + align:start position:0% +plane + + + align:start position:0% +plane +that is we have buildings and trees and + + align:start position:0% +that is we have buildings and trees and + + + align:start position:0% +that is we have buildings and trees and +stuff we sometimes go up in the z-axis + + align:start position:0% +stuff we sometimes go up in the z-axis + + + align:start position:0% +stuff we sometimes go up in the z-axis +but most we live in a 2d plane + + align:start position:0% +but most we live in a 2d plane + + + align:start position:0% +but most we live in a 2d plane +but that's not true of all animals so + + align:start position:0% +but that's not true of all animals so + + + align:start position:0% +but that's not true of all animals so +recall the bat that i mentioned last + + align:start position:0% +recall the bat that i mentioned last + + + align:start position:0% +recall the bat that i mentioned last +time these amazing flyers and navigators + + align:start position:0% +time these amazing flyers and navigators + + + align:start position:0% +time these amazing flyers and navigators +who fly in 3d and complicated + + align:start position:0% +who fly in 3d and complicated + + + align:start position:0% +who fly in 3d and complicated +trajectories and yet have + + align:start position:0% +trajectories and yet have + + + align:start position:0% +trajectories and yet have +amazing abilities to keep track of where + + align:start position:0% +amazing abilities to keep track of where + + + align:start position:0% +amazing abilities to keep track of where +they are over 30 to 50 miles that they + + align:start position:0% +they are over 30 to 50 miles that they + + + align:start position:0% +they are over 30 to 50 miles that they +fly at night + + align:start position:0% +fly at night + + + align:start position:0% +fly at night +and even as they change their + + align:start position:0% +and even as they change their + + + align:start position:0% +and even as they change their +orientation + + align:start position:0% +orientation + + + align:start position:0% +orientation +well it turns out that in the + + align:start position:0% +well it turns out that in the + + + align:start position:0% +well it turns out that in the +hippocampus of bats there's a bunch of + + align:start position:0% +hippocampus of bats there's a bunch of + + + align:start position:0% +hippocampus of bats there's a bunch of +work where people have + + align:start position:0% +work where people have + + + align:start position:0% +work where people have +put + + align:start position:0% +put + + + align:start position:0% +put +um remote + + align:start position:0% +um remote + + + align:start position:0% +um remote +what do you call these things recording + + align:start position:0% +what do you call these things recording + + + align:start position:0% +what do you call these things recording +devices on bats where you can remotely + + align:start position:0% +devices on bats where you can remotely + + + align:start position:0% +devices on bats where you can remotely +record + + align:start position:0% +record + + + align:start position:0% +record +neural activity in the hippocampus as + + align:start position:0% +neural activity in the hippocampus as + + + align:start position:0% +neural activity in the hippocampus as +the bat flies around + + align:start position:0% +the bat flies around + + + align:start position:0% +the bat flies around +and turns out that bats have play cells + + align:start position:0% +and turns out that bats have play cells + + + align:start position:0% +and turns out that bats have play cells +too and their place cells + + align:start position:0% +too and their place cells + + + align:start position:0% +too and their place cells +as they they all also can do this in a + + align:start position:0% +as they they all also can do this in a + + + align:start position:0% +as they they all also can do this in a +lab environment where they're flying + + align:start position:0% +lab environment where they're flying + + + align:start position:0% +lab environment where they're flying +around and you keep track of their + + align:start position:0% +around and you keep track of their + + + align:start position:0% +around and you keep track of their +location uh with cameras so you know + + align:start position:0% +location uh with cameras so you know + + + align:start position:0% +location uh with cameras so you know +exactly where they are in 3d space + + align:start position:0% +exactly where they are in 3d space + + + align:start position:0% +exactly where they are in 3d space +and it turns out that place cells in + + align:start position:0% +and it turns out that place cells in + + + align:start position:0% +and it turns out that place cells in +bats are three-dimensional because bats + + align:start position:0% +bats are three-dimensional because bats + + + align:start position:0% +bats are three-dimensional because bats +live in a three-dimensional world + + align:start position:0% +live in a three-dimensional world + + + align:start position:0% +live in a three-dimensional world +so whereas rodent these would be a bunch + + align:start position:0% +so whereas rodent these would be a bunch + + + align:start position:0% +so whereas rodent these would be a bunch +of kind of schematized place cells + + align:start position:0% +of kind of schematized place cells + + + align:start position:0% +of kind of schematized place cells +for uh of different hippocampal cells in + + align:start position:0% +for uh of different hippocampal cells in + + + align:start position:0% +for uh of different hippocampal cells in +a rodent + + align:start position:0% +a rodent + + + align:start position:0% +a rodent +these are different place cells + + align:start position:0% +these are different place cells + + + align:start position:0% +these are different place cells +for different hippocampal cells and a + + align:start position:0% +for different hippocampal cells and a + + + align:start position:0% +for different hippocampal cells and a +bat + + align:start position:0% +bat + + + align:start position:0% +bat +makes sense bats need this they need to + + align:start position:0% +makes sense bats need this they need to + + + align:start position:0% +makes sense bats need this they need to +know not making sense okay so the bat is + + align:start position:0% +know not making sense okay so the bat is + + + align:start position:0% +know not making sense okay so the bat is +moving around in three dimensions its + + align:start position:0% +moving around in three dimensions its + + + align:start position:0% +moving around in three dimensions its +place field isn't just like the one i + + align:start position:0% +place field isn't just like the one i + + + align:start position:0% +place field isn't just like the one i +did there i can't act this out because i + + align:start position:0% +did there i can't act this out because i + + + align:start position:0% +did there i can't act this out because i +can't fly but that play cell might fire + + align:start position:0% +can't fly but that play cell might fire + + + align:start position:0% +can't fly but that play cell might fire +over in that location but then if the + + align:start position:0% +over in that location but then if the + + + align:start position:0% +over in that location but then if the +bat flew directly above it it wouldn't + + align:start position:0% +bat flew directly above it it wouldn't + + + align:start position:0% +bat flew directly above it it wouldn't +so it's got three dimensions okay + + align:start position:0% + + + + align:start position:0% + +um okay + + align:start position:0% +um okay + + + align:start position:0% +um okay +so i said before that i had one of those + + align:start position:0% +so i said before that i had one of those + + + align:start position:0% +so i said before that i had one of those +and i acted it out but what's the + + align:start position:0% +and i acted it out but what's the + + + align:start position:0% +and i acted it out but what's the +evidence for that + + align:start position:0% +evidence for that + + + align:start position:0% +evidence for that +that evidence in humans came way after + + align:start position:0% +that evidence in humans came way after + + + align:start position:0% +that evidence in humans came way after +the evidence in rodents + + align:start position:0% +the evidence in rodents + + + align:start position:0% +the evidence in rodents +um because as you can imagine it's + + align:start position:0% +um because as you can imagine it's + + + align:start position:0% +um because as you can imagine it's +harder to arrange to record from + + align:start position:0% +harder to arrange to record from + + + align:start position:0% +harder to arrange to record from +individual neurons in human + + align:start position:0% +individual neurons in human + + + align:start position:0% +individual neurons in human +hippocampuses + + align:start position:0% +hippocampuses + + + align:start position:0% +hippocampuses +nonetheless + + align:start position:0% +nonetheless + + + align:start position:0% +nonetheless +as i've mentioned a few times there are + + align:start position:0% +as i've mentioned a few times there are + + + align:start position:0% +as i've mentioned a few times there are +occasional opportunities where a + + align:start position:0% +occasional opportunities where a + + + align:start position:0% +occasional opportunities where a +neurosurgeon has stuck an electrode in + + align:start position:0% +neurosurgeon has stuck an electrode in + + + align:start position:0% +neurosurgeon has stuck an electrode in +an interesting part of the brain for + + align:start position:0% +an interesting part of the brain for + + + align:start position:0% +an interesting part of the brain for +clinical reasons and the patient and the + + align:start position:0% +clinical reasons and the patient and the + + + align:start position:0% +clinical reasons and the patient and the +neurosurgeon are nice enough + + align:start position:0% +neurosurgeon are nice enough + + + align:start position:0% +neurosurgeon are nice enough +to let scientists collect data + + align:start position:0% +to let scientists collect data + + + align:start position:0% +to let scientists collect data +so i'm going to show you a really gross + + align:start position:0% +so i'm going to show you a really gross + + + align:start position:0% +so i'm going to show you a really gross +bloody picture if that's going to bother + + align:start position:0% +bloody picture if that's going to bother + + + align:start position:0% +bloody picture if that's going to bother +you just look away okay + + align:start position:0% +you just look away okay + + + align:start position:0% +you just look away okay +so um this is neurosurgery you take the + + align:start position:0% +so um this is neurosurgery you take the + + + align:start position:0% +so um this is neurosurgery you take the +skull off you take the dura off that's + + align:start position:0% +skull off you take the dura off that's + + + align:start position:0% +skull off you take the dura off that's +the direct surface of the brain the + + align:start position:0% +the direct surface of the brain the + + + align:start position:0% +the direct surface of the brain the +neurosurgeons stick electrodes right on + + align:start position:0% +neurosurgeons stick electrodes right on + + + align:start position:0% +neurosurgeons stick electrodes right on +top of there and in this case they put + + align:start position:0% +top of there and in this case they put + + + align:start position:0% +top of there and in this case they put +them deep inside the brain okay the + + align:start position:0% +them deep inside the brain okay the + + + align:start position:0% +them deep inside the brain okay the +gross pictures are gone we have just a + + align:start position:0% +gross pictures are gone we have just a + + + align:start position:0% +gross pictures are gone we have just a +nice clean + + align:start position:0% +nice clean + + + align:start position:0% +nice clean +uh x-ray here um so in these cases these + + align:start position:0% +uh x-ray here um so in these cases these + + + align:start position:0% +uh x-ray here um so in these cases these +are um + + align:start position:0% +are um + + + align:start position:0% +are um +this is a patient who's got an electrode + + align:start position:0% +this is a patient who's got an electrode + + + align:start position:0% +this is a patient who's got an electrode +sticking straight into the brain from + + align:start position:0% +sticking straight into the brain from + + + align:start position:0% +sticking straight into the brain from +the surface straight down into the + + align:start position:0% +the surface straight down into the + + + align:start position:0% +the surface straight down into the +hippocampus + + align:start position:0% +hippocampus + + + align:start position:0% +hippocampus +okay + + align:start position:0% +okay + + + align:start position:0% +okay +kind of horrifying but + + align:start position:0% +kind of horrifying but + + + align:start position:0% +kind of horrifying but +sometimes clinically called for seizures + + align:start position:0% +sometimes clinically called for seizures + + + align:start position:0% +sometimes clinically called for seizures +very often start in hippocampus so this + + align:start position:0% +very often start in hippocampus so this + + + align:start position:0% +very often start in hippocampus so this +is a common place for + + align:start position:0% +is a common place for + + + align:start position:0% +is a common place for +clinicians to put electrodes + + align:start position:0% +clinicians to put electrodes + + + align:start position:0% +clinicians to put electrodes +um and so uh what would you do if you + + align:start position:0% +um and so uh what would you do if you + + + align:start position:0% +um and so uh what would you do if you +had a patient who was willing to do your + + align:start position:0% +had a patient who was willing to do your + + + align:start position:0% +had a patient who was willing to do your +short experiment while hanging out in + + align:start position:0% +short experiment while hanging out in + + + align:start position:0% +short experiment while hanging out in +the hospital waiting to have a seizure + + align:start position:0% +the hospital waiting to have a seizure + + + align:start position:0% +the hospital waiting to have a seizure +with electrodes in their hippocampus + + align:start position:0% +with electrodes in their hippocampus + + + align:start position:0% +with electrodes in their hippocampus +well duh you'd have them play a little + + align:start position:0% +well duh you'd have them play a little + + + align:start position:0% +well duh you'd have them play a little +um a little game in a virtual space and + + align:start position:0% +um a little game in a virtual space and + + + align:start position:0% +um a little game in a virtual space and +some kind of you don't even need vr you + + align:start position:0% +some kind of you don't even need vr you + + + align:start position:0% +some kind of you don't even need vr you +can use a pretty + + align:start position:0% +can use a pretty + + + align:start position:0% +can use a pretty +cheesy little video game and i'm sure + + align:start position:0% +cheesy little video game and i'm sure + + + align:start position:0% +cheesy little video game and i'm sure +this one was quite cheesy this study was + + align:start position:0% +this one was quite cheesy this study was + + + align:start position:0% +this one was quite cheesy this study was +done back in 2003 + + align:start position:0% +done back in 2003 + + + align:start position:0% +done back in 2003 +so + + align:start position:0% +so + + + align:start position:0% +so +they had patients navigate through a + + align:start position:0% +they had patients navigate through a + + + align:start position:0% +they had patients navigate through a +space this is an aerial view of the + + align:start position:0% +space this is an aerial view of the + + + align:start position:0% +space this is an aerial view of the +space the patients didn't see that they + + align:start position:0% +space the patients didn't see that they + + + align:start position:0% +space the patients didn't see that they +saw this kind of front view and they + + align:start position:0% +saw this kind of front view and they + + + align:start position:0% +saw this kind of front view and they +kind of navigated around with the + + align:start position:0% +kind of navigated around with the + + + align:start position:0% +kind of navigated around with the +joystick in that space and there were + + align:start position:0% +joystick in that space and there were + + + align:start position:0% +joystick in that space and there were +three + + align:start position:0% +three + + + align:start position:0% +three +kind of visually recognizable kind of + + align:start position:0% +kind of visually recognizable kind of + + + align:start position:0% +kind of visually recognizable kind of +locations in that space and they had to + + align:start position:0% +locations in that space and they had to + + + align:start position:0% +locations in that space and they had to +do things to go from one location to + + align:start position:0% +do things to go from one location to + + + align:start position:0% +do things to go from one location to +another + + align:start position:0% +another + + + align:start position:0% +another +okay details don't really matter + + align:start position:0% +okay details don't really matter + + + align:start position:0% +okay details don't really matter +so all the while um ekstrom and + + align:start position:0% +so all the while um ekstrom and + + + align:start position:0% +so all the while um ekstrom and +colleagues are recording from individual + + align:start position:0% +colleagues are recording from individual + + + align:start position:0% +colleagues are recording from individual +neurons in this patient's hippocampus + + align:start position:0% +neurons in this patient's hippocampus + + + align:start position:0% +neurons in this patient's hippocampus +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so here's an example of a place cell so + + align:start position:0% +so here's an example of a place cell so + + + align:start position:0% +so here's an example of a place cell so +this is a diagram of the space i just + + align:start position:0% +this is a diagram of the space i just + + + align:start position:0% +this is a diagram of the space i just +showed you right with those + + align:start position:0% +showed you right with those + + + align:start position:0% +showed you right with those +three recognizable locations and other + + align:start position:0% +three recognizable locations and other + + + align:start position:0% +three recognizable locations and other +locations that the patient could + + align:start position:0% +locations that the patient could + + + align:start position:0% +locations that the patient could +virtually navigate through with the + + align:start position:0% +virtually navigate through with the + + + align:start position:0% +virtually navigate through with the +joystick the red lines are the patient's + + align:start position:0% +joystick the red lines are the patient's + + + align:start position:0% +joystick the red lines are the patient's +trajectory as they moved around in that + + align:start position:0% +trajectory as they moved around in that + + + align:start position:0% +trajectory as they moved around in that +space + + align:start position:0% +space + + + align:start position:0% +space +and the colors within each square are + + align:start position:0% +and the colors within each square are + + + align:start position:0% +and the colors within each square are +the average firing rate + + align:start position:0% +the average firing rate + + + align:start position:0% +the average firing rate +when the patient navigated through that + + align:start position:0% +when the patient navigated through that + + + align:start position:0% +when the patient navigated through that +location + + align:start position:0% +location + + + align:start position:0% +location +and so this is the place field of that + + align:start position:0% +and so this is the place field of that + + + align:start position:0% +and so this is the place field of that +individual cell in this patient's brain + + align:start position:0% +individual cell in this patient's brain + + + align:start position:0% +individual cell in this patient's brain +as they went through this space because + + align:start position:0% +as they went through this space because + + + align:start position:0% +as they went through this space because +the firing rate there was around five + + align:start position:0% +the firing rate there was around five + + + align:start position:0% +the firing rate there was around five +hertz compared to you know three hertz + + align:start position:0% +hertz compared to you know three hertz + + + align:start position:0% +hertz compared to you know three hertz +for some other locations and mostly + + align:start position:0% +for some other locations and mostly + + + align:start position:0% +for some other locations and mostly +lower than that + + align:start position:0% +lower than that + + + align:start position:0% +lower than that +okay does that make sense so we're just + + align:start position:0% +okay does that make sense so we're just + + + align:start position:0% +okay does that make sense so we're just +just like the rodent experiment but it's + + align:start position:0% +just like the rodent experiment but it's + + + align:start position:0% +just like the rodent experiment but it's +a person with a joystick looking at this + + align:start position:0% +a person with a joystick looking at this + + + align:start position:0% +a person with a joystick looking at this +space as they go through this virtual + + align:start position:0% +space as they go through this virtual + + + align:start position:0% +space as they go through this virtual +environment and we're mapping out their + + align:start position:0% +environment and we're mapping out their + + + align:start position:0% +environment and we're mapping out their +place fields like that okay + + align:start position:0% +place fields like that okay + + + align:start position:0% +place fields like that okay +so that shows that humans have placed + + align:start position:0% +so that shows that humans have placed + + + align:start position:0% +so that shows that humans have placed +fields in their hippocampus just as + + align:start position:0% +fields in their hippocampus just as + + + align:start position:0% +fields in their hippocampus just as +rodents and bats do yeah + + align:start position:0% +rodents and bats do yeah + + + align:start position:0% +rodents and bats do yeah +all this is like independent of + + align:start position:0% +all this is like independent of + + + align:start position:0% +all this is like independent of +landmarks + + align:start position:0% +landmarks + + + align:start position:0% +landmarks +um that's a very complicated question + + align:start position:0% +um that's a very complicated question + + + align:start position:0% +um that's a very complicated question +this patient had access to landmarks + + align:start position:0% +this patient had access to landmarks + + + align:start position:0% +this patient had access to landmarks +they are seeing as they go through + + align:start position:0% +they are seeing as they go through + + + align:start position:0% +they are seeing as they go through +so one could ask for example if you did + + align:start position:0% +so one could ask for example if you did + + + align:start position:0% +so one could ask for example if you did +it with your eyes closed and you had to + + align:start position:0% +it with your eyes closed and you had to + + + align:start position:0% +it with your eyes closed and you had to +go by dead reckoning remembering the + + align:start position:0% +go by dead reckoning remembering the + + + align:start position:0% +go by dead reckoning remembering the +left and right turns you had in a + + align:start position:0% +left and right turns you had in a + + + align:start position:0% +left and right turns you had in a +familiar environment how well could + + align:start position:0% +familiar environment how well could + + + align:start position:0% +familiar environment how well could +these things go they would go for at + + align:start position:0% +these things go they would go for at + + + align:start position:0% +these things go they would go for at +least a while + + align:start position:0% +least a while + + + align:start position:0% +least a while +they'd probably go for longer in rodents + + align:start position:0% +they'd probably go for longer in rodents + + + align:start position:0% +they'd probably go for longer in rodents +because rodents + + align:start position:0% +because rodents + + + align:start position:0% +because rodents +are more accustomed to navigating in the + + align:start position:0% +are more accustomed to navigating in the + + + align:start position:0% +are more accustomed to navigating in the +dark and they rely less on visual cues + + align:start position:0% +dark and they rely less on visual cues + + + align:start position:0% +dark and they rely less on visual cues +and more on other cues + + align:start position:0% +and more on other cues + + + align:start position:0% +and more on other cues +but yeah these are not + + align:start position:0% +but yeah these are not + + + align:start position:0% +but yeah these are not +place cells aren't just visually + + align:start position:0% +place cells aren't just visually + + + align:start position:0% +place cells aren't just visually +responsive right so + + align:start position:0% +responsive right so + + + align:start position:0% +responsive right so +if we had like for example if we set up + + align:start position:0% +if we had like for example if we set up + + + align:start position:0% +if we had like for example if we set up +a a um a distinctive sound source in + + align:start position:0% +a a um a distinctive sound source in + + + align:start position:0% +a a um a distinctive sound source in +this corner of the room and a different + + align:start position:0% +this corner of the room and a different + + + align:start position:0% +this corner of the room and a different +you know like say somebody was singing + + align:start position:0% +you know like say somebody was singing + + + align:start position:0% +you know like say somebody was singing +quietly over here + + align:start position:0% +quietly over here + + + align:start position:0% +quietly over here +and we um + + align:start position:0% +and we um + + + align:start position:0% +and we um +tied a dog over there who was barking + + align:start position:0% +tied a dog over there who was barking + + + align:start position:0% +tied a dog over there who was barking +right and you you walked around in this + + align:start position:0% +right and you you walked around in this + + + align:start position:0% +right and you you walked around in this +room with your eyes closed you'd have a + + align:start position:0% +room with your eyes closed you'd have a + + + align:start position:0% +room with your eyes closed you'd have a +pretty you'd have a good way to keep + + align:start position:0% +pretty you'd have a good way to keep + + + align:start position:0% +pretty you'd have a good way to keep +track of your bearings as you moved + + align:start position:0% +track of your bearings as you moved + + + align:start position:0% +track of your bearings as you moved +around because you'd know that the + + align:start position:0% +around because you'd know that the + + + align:start position:0% +around because you'd know that the +singing was coming from here and the dog + + align:start position:0% +singing was coming from here and the dog + + + align:start position:0% +singing was coming from here and the dog +barking was coming from there you + + align:start position:0% +barking was coming from there you + + + align:start position:0% +barking was coming from there you +wouldn't be seeing anything your eyes + + align:start position:0% +wouldn't be seeing anything your eyes + + + align:start position:0% +wouldn't be seeing anything your eyes +would be closed but your place cells + + align:start position:0% +would be closed but your place cells + + + align:start position:0% +would be closed but your place cells +would work pretty well okay so whenever + + align:start position:0% +would work pretty well okay so whenever + + + align:start position:0% +would work pretty well okay so whenever +you have some basis for knowing where + + align:start position:0% +you have some basis for knowing where + + + align:start position:0% +you have some basis for knowing where +you are no matter what modality is + + align:start position:0% +you are no matter what modality is + + + align:start position:0% +you are no matter what modality is +telling you that + + align:start position:0% +telling you that + + + align:start position:0% +telling you that +usually it's many modalities those place + + align:start position:0% +usually it's many modalities those place + + + align:start position:0% +usually it's many modalities those place +cells will go + + align:start position:0% +cells will go + + + align:start position:0% +cells will go +okay + + align:start position:0% +okay + + + align:start position:0% +okay +okay so humans have these things too so + + align:start position:0% +okay so humans have these things too so + + + align:start position:0% +okay so humans have these things too so +you can think of the place cell as the + + align:start position:0% +you can think of the place cell as the + + + align:start position:0% +you can think of the place cell as the +kind of you are here system right + + align:start position:0% +kind of you are here system right + + + align:start position:0% +kind of you are here system right +that is the whole set of place cells any + + align:start position:0% +that is the whole set of place cells any + + + align:start position:0% +that is the whole set of place cells any +one place will only tell you are you in + + align:start position:0% +one place will only tell you are you in + + + align:start position:0% +one place will only tell you are you in +this particular location or not but you + + align:start position:0% +this particular location or not but you + + + align:start position:0% +this particular location or not but you +have a whole array of them then + + align:start position:0% +have a whole array of them then + + + align:start position:0% +have a whole array of them then +collectively + + align:start position:0% +collectively + + + align:start position:0% +collectively +that that whole representation across + + align:start position:0% +that that whole representation across + + + align:start position:0% +that that whole representation across +all of those neurons can tell you where + + align:start position:0% +all of those neurons can tell you where + + + align:start position:0% +all of those neurons can tell you where +you are in your familiar environment + + align:start position:0% +you are in your familiar environment + + + align:start position:0% +you are in your familiar environment +okay + + align:start position:0% +okay + + + align:start position:0% +okay +but if you want to not just know where + + align:start position:0% +but if you want to not just know where + + + align:start position:0% +but if you want to not just know where +you are but you want to go somewhere + + align:start position:0% +you are but you want to go somewhere + + + align:start position:0% +you are but you want to go somewhere +else like there + + align:start position:0% +else like there + + + align:start position:0% +else like there +you also need to know your current + + align:start position:0% +you also need to know your current + + + align:start position:0% +you also need to know your current +heading as we discussed last time okay + + align:start position:0% +heading as we discussed last time okay + + + align:start position:0% +heading as we discussed last time okay +so it turns out + + align:start position:0% +so it turns out + + + align:start position:0% +so it turns out +that there's a whole other batch of + + align:start position:0% +that there's a whole other batch of + + + align:start position:0% +that there's a whole other batch of +cells + + align:start position:0% +cells + + + align:start position:0% +cells +that tell you what way you're heading + + align:start position:0% +that tell you what way you're heading + + + align:start position:0% +that tell you what way you're heading +okay these are called head direction + + align:start position:0% +okay these are called head direction + + + align:start position:0% +okay these are called head direction +cells + + align:start position:0% +cells + + + align:start position:0% +cells +also first studied in rodents + + align:start position:0% +also first studied in rodents + + + align:start position:0% +also first studied in rodents +and each head direction cell responds + + align:start position:0% +and each head direction cell responds + + + align:start position:0% +and each head direction cell responds +when that rodent is heading in a + + align:start position:0% +when that rodent is heading in a + + + align:start position:0% +when that rodent is heading in a +particular direction + + align:start position:0% +particular direction + + + align:start position:0% +particular direction +not in another direction + + align:start position:0% +not in another direction + + + align:start position:0% +not in another direction +okay so for example + + align:start position:0% +okay so for example + + + align:start position:0% +okay so for example +you have you know + + align:start position:0% +you have you know + + + align:start position:0% +you have you know +if we're mapping along the x-axis + + align:start position:0% +if we're mapping along the x-axis + + + align:start position:0% +if we're mapping along the x-axis +different heading direction so the + + align:start position:0% +different heading direction so the + + + align:start position:0% +different heading direction so the +rodent is facing in different directions + + align:start position:0% +rodent is facing in different directions + + + align:start position:0% +rodent is facing in different directions +in his environment you map up the whole + + align:start position:0% +in his environment you map up the whole + + + align:start position:0% +in his environment you map up the whole +360 degrees + + align:start position:0% +360 degrees + + + align:start position:0% +360 degrees +this would be the response of one cell + + align:start position:0% +this would be the response of one cell + + + align:start position:0% +this would be the response of one cell +as that + + align:start position:0% +as that + + + align:start position:0% +as that +rodent moves around + + align:start position:0% +rodent moves around + + + align:start position:0% +rodent moves around +this one will be tuned to this + + align:start position:0% +this one will be tuned to this + + + align:start position:0% +this one will be tuned to this +particular direction it would fire only + + align:start position:0% +particular direction it would fire only + + + align:start position:0% +particular direction it would fire only +when the rodent was facing this way not + + align:start position:0% +when the rodent was facing this way not + + + align:start position:0% +when the rodent was facing this way not +when it was facing this way or this way + + align:start position:0% +when it was facing this way or this way + + + align:start position:0% +when it was facing this way or this way +or this way or this way + + align:start position:0% +or this way or this way + + + align:start position:0% +or this way or this way +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so everybody get how where you are in + + align:start position:0% +so everybody get how where you are in + + + align:start position:0% +so everybody get how where you are in +space is different that's not a very + + align:start position:0% +space is different that's not a very + + + align:start position:0% +space is different that's not a very +good way to show this + + align:start position:0% + + + + align:start position:0% + +where you are in space + + align:start position:0% +where you are in space + + + align:start position:0% +where you are in space +is different from where you're + + align:start position:0% +is different from where you're + + + align:start position:0% +is different from where you're +aimed and headed in that location okay + + align:start position:0% +aimed and headed in that location okay + + + align:start position:0% +aimed and headed in that location okay +two orthogonal axes of + + align:start position:0% +two orthogonal axes of + + + align:start position:0% +two orthogonal axes of +relevant to your location yeah + + align:start position:0% +relevant to your location yeah + + + align:start position:0% +relevant to your location yeah +so this isn't the angle of the head + + align:start position:0% +so this isn't the angle of the head + + + align:start position:0% +so this isn't the angle of the head +respect the body right it's the entire + + align:start position:0% +respect the body right it's the entire + + + align:start position:0% +respect the body right it's the entire +um i think + + align:start position:0% +um i think + + + align:start position:0% +um i think +i meant to look that up again because + + align:start position:0% +i meant to look that up again because + + + align:start position:0% +i meant to look that up again because +this question always arises um i think + + align:start position:0% +this question always arises um i think + + + align:start position:0% +this question always arises um i think +that there's some muck about that in the + + align:start position:0% +that there's some muck about that in the + + + align:start position:0% +that there's some muck about that in the +literature which is why i never remember + + align:start position:0% +literature which is why i never remember + + + align:start position:0% +literature which is why i never remember +a clear answer usually in a rodent + + align:start position:0% +a clear answer usually in a rodent + + + align:start position:0% +a clear answer usually in a rodent +especially they're the same + + align:start position:0% +especially they're the same + + + align:start position:0% +especially they're the same +um + + align:start position:0% +um + + + align:start position:0% +um +and whether you know because you know + + align:start position:0% +and whether you know because you know + + + align:start position:0% +and whether you know because you know +runs can turn their heads a little bit + + align:start position:0% +runs can turn their heads a little bit + + + align:start position:0% +runs can turn their heads a little bit +but you know mostly they're gonna + + align:start position:0% +but you know mostly they're gonna + + + align:start position:0% +but you know mostly they're gonna +keep it aimed the way they're moving + + align:start position:0% +keep it aimed the way they're moving + + + align:start position:0% +keep it aimed the way they're moving +um so i don't know this is a long + + align:start position:0% +um so i don't know this is a long + + + align:start position:0% +um so i don't know this is a long +complicated excuse that i forget what + + align:start position:0% +complicated excuse that i forget what + + + align:start position:0% +complicated excuse that i forget what +the answer to that is um but send me an + + align:start position:0% +the answer to that is um but send me an + + + align:start position:0% +the answer to that is um but send me an +email and i'll look it up i meant to + + align:start position:0% +email and i'll look it up i meant to + + + align:start position:0% +email and i'll look it up i meant to +before this lecture just ran out of time + + align:start position:0% +before this lecture just ran out of time + + + align:start position:0% +before this lecture just ran out of time +um + + align:start position:0% +um + + + align:start position:0% +um +okay + + align:start position:0% +okay + + + align:start position:0% +okay +most of the time they'll be the same i + + align:start position:0% +most of the time they'll be the same i + + + align:start position:0% +most of the time they'll be the same i +actually i'm i'm pretty sure it's which + + align:start position:0% +actually i'm i'm pretty sure it's which + + + align:start position:0% +actually i'm i'm pretty sure it's which +way your body's facing because if i turn + + align:start position:0% +way your body's facing because if i turn + + + align:start position:0% +way your body's facing because if i turn +like this well anyway i'm not going that + + align:start position:0% +like this well anyway i'm not going that + + + align:start position:0% +like this well anyway i'm not going that +way yeah and have you found at least 360 + + align:start position:0% +way yeah and have you found at least 360 + + + align:start position:0% +way yeah and have you found at least 360 +cents for each sort of angle + + align:start position:0% +cents for each sort of angle + + + align:start position:0% +cents for each sort of angle +i mean are there cells for each yes yes + + align:start position:0% +i mean are there cells for each yes yes + + + align:start position:0% +i mean are there cells for each yes yes +they they pretty much evenly tile the + + align:start position:0% +they they pretty much evenly tile the + + + align:start position:0% +they they pretty much evenly tile the +360 degrees around the animal yeah so + + align:start position:0% +360 degrees around the animal yeah so + + + align:start position:0% +360 degrees around the animal yeah so +collectively that whole set of cells + + align:start position:0% +collectively that whole set of cells + + + align:start position:0% +collectively that whole set of cells +just as a collective set of place cells + + align:start position:0% +just as a collective set of place cells + + + align:start position:0% +just as a collective set of place cells +is sufficient to tell the animal where + + align:start position:0% +is sufficient to tell the animal where + + + align:start position:0% +is sufficient to tell the animal where +it is a collective set of head direction + + align:start position:0% +it is a collective set of head direction + + + align:start position:0% +it is a collective set of head direction +cells is sufficient to tell the animal + + align:start position:0% +cells is sufficient to tell the animal + + + align:start position:0% +cells is sufficient to tell the animal +which way it's oriented + + align:start position:0% +which way it's oriented + + + align:start position:0% +which way it's oriented +okay + + align:start position:0% +okay + + + align:start position:0% +okay +okay i think we just said all these + + align:start position:0% +okay i think we just said all these + + + align:start position:0% +okay i think we just said all these +things are in a structure called the + + align:start position:0% +things are in a structure called the + + + align:start position:0% +things are in a structure called the +well first found in a structure called + + align:start position:0% +well first found in a structure called + + + align:start position:0% +well first found in a structure called +the subiculum which is part of the + + align:start position:0% +the subiculum which is part of the + + + align:start position:0% +the subiculum which is part of the +hippocampus but since then they've been + + align:start position:0% +hippocampus but since then they've been + + + align:start position:0% +hippocampus but since then they've been +found in lots of different regions you + + align:start position:0% +found in lots of different regions you + + + align:start position:0% +found in lots of different regions you +don't need to remember that + + align:start position:0% +don't need to remember that + + + align:start position:0% +don't need to remember that +um so they get input from lots of + + align:start position:0% +um so they get input from lots of + + + align:start position:0% +um so they get input from lots of +different information there's many + + align:start position:0% +different information there's many + + + align:start position:0% +different information there's many +different ways to know which way we're + + align:start position:0% +different ways to know which way we're + + + align:start position:0% +different ways to know which way we're +oriented + + align:start position:0% +oriented + + + align:start position:0% +oriented +for example too bad we don't have a + + align:start position:0% +for example too bad we don't have a + + + align:start position:0% +for example too bad we don't have a +rotating chair + + align:start position:0% +rotating chair + + + align:start position:0% +rotating chair +if we did i would have done the + + align:start position:0% +if we did i would have done the + + + align:start position:0% +if we did i would have done the +following ridiculous thing i would have + + align:start position:0% +following ridiculous thing i would have + + + align:start position:0% +following ridiculous thing i would have +sat one of you in it and told you to + + align:start position:0% +sat one of you in it and told you to + + + align:start position:0% +sat one of you in it and told you to +close your eyes and i would suddenly + + align:start position:0% +close your eyes and i would suddenly + + + align:start position:0% +close your eyes and i would suddenly +turn it + + align:start position:0% +turn it + + + align:start position:0% +turn it +and the person in the chair would notice + + align:start position:0% +and the person in the chair would notice + + + align:start position:0% +and the person in the chair would notice +that right that's your vestibular system + + align:start position:0% +that right that's your vestibular system + + + align:start position:0% +that right that's your vestibular system +that tells you if your body's being + + align:start position:0% +that tells you if your body's being + + + align:start position:0% +that tells you if your body's being +turned even if you yourself don't decide + + align:start position:0% +turned even if you yourself don't decide + + + align:start position:0% +turned even if you yourself don't decide +to turn it it will tell you if you get + + align:start position:0% +to turn it it will tell you if you get + + + align:start position:0% +to turn it it will tell you if you get +turned that's another cue that provides + + align:start position:0% +turned that's another cue that provides + + + align:start position:0% +turned that's another cue that provides +input to the head direction cells just + + align:start position:0% +input to the head direction cells just + + + align:start position:0% +input to the head direction cells just +as visual information does and + + align:start position:0% +as visual information does and + + + align:start position:0% +as visual information does and +potentially auditory information and + + align:start position:0% +potentially auditory information and + + + align:start position:0% +potentially auditory information and +lots of other kinds of information + + align:start position:0% +lots of other kinds of information + + + align:start position:0% +lots of other kinds of information +so many different sources of information + + align:start position:0% +so many different sources of information + + + align:start position:0% +so many different sources of information +feed in to inform these head direction + + align:start position:0% +feed in to inform these head direction + + + align:start position:0% +feed in to inform these head direction +cells about the orientation of the + + align:start position:0% +cells about the orientation of the + + + align:start position:0% +cells about the orientation of the +animal + + align:start position:0% +animal + + + align:start position:0% +animal +okay + + align:start position:0% +okay + + + align:start position:0% +okay +all right so you can think of this as + + align:start position:0% +all right so you can think of this as + + + align:start position:0% +all right so you can think of this as +the brain's compass right + + align:start position:0% +the brain's compass right + + + align:start position:0% +the brain's compass right +telling the organism what way they're + + align:start position:0% +telling the organism what way they're + + + align:start position:0% +telling the organism what way they're +facing + + align:start position:0% +facing + + + align:start position:0% +facing +okay and + + align:start position:0% +okay and + + + align:start position:0% +okay and +lots of organisms have versions of this + + align:start position:0% +lots of organisms have versions of this + + + align:start position:0% +lots of organisms have versions of this +in the fly there's an amazing structure + + align:start position:0% +in the fly there's an amazing structure + + + align:start position:0% +in the fly there's an amazing structure +that was discovered just a couple years + + align:start position:0% +that was discovered just a couple years + + + align:start position:0% +that was discovered just a couple years +ago where the there's a whole kind of + + align:start position:0% +ago where the there's a whole kind of + + + align:start position:0% +ago where the there's a whole kind of +layout of this little neural structure i + + align:start position:0% +layout of this little neural structure i + + + align:start position:0% +layout of this little neural structure i +forget what it's called but actually + + align:start position:0% +forget what it's called but actually + + + align:start position:0% +forget what it's called but actually +spatially in that structure there's a + + align:start position:0% +spatially in that structure there's a + + + align:start position:0% +spatially in that structure there's a +little array + + align:start position:0% +little array + + + align:start position:0% +little array +of direction cells so actually you could + + align:start position:0% +of direction cells so actually you could + + + align:start position:0% +of direction cells so actually you could +see it in a little spatial map + + align:start position:0% +see it in a little spatial map + + + align:start position:0% +see it in a little spatial map +of direction + + align:start position:0% +of direction + + + align:start position:0% +of direction +in that little structure in the fly + + align:start position:0% +in that little structure in the fly + + + align:start position:0% +in that little structure in the fly +okay in humans and primates and rodents + + align:start position:0% +okay in humans and primates and rodents + + + align:start position:0% +okay in humans and primates and rodents +it's not organized spatially like a + + align:start position:0% +it's not organized spatially like a + + + align:start position:0% +it's not organized spatially like a +literal + + align:start position:0% +literal + + + align:start position:0% +literal +map of direction + + align:start position:0% +map of direction + + + align:start position:0% +map of direction +okay so now we have where you are and + + align:start position:0% +okay so now we have where you are and + + + align:start position:0% +okay so now we have where you are and +which way you're facing + + align:start position:0% +which way you're facing + + + align:start position:0% +which way you're facing +okay + + align:start position:0% +okay + + + align:start position:0% +okay +you know one pool of cells place cells + + align:start position:0% +you know one pool of cells place cells + + + align:start position:0% +you know one pool of cells place cells +for where you are another pool of cells + + align:start position:0% +for where you are another pool of cells + + + align:start position:0% +for where you are another pool of cells +for which way you're heading + + align:start position:0% +for which way you're heading + + + align:start position:0% +for which way you're heading +but those are just we're just getting + + align:start position:0% +but those are just we're just getting + + + align:start position:0% +but those are just we're just getting +going here the coolest navigation + + align:start position:0% +going here the coolest navigation + + + align:start position:0% +going here the coolest navigation +related cells + + align:start position:0% +related cells + + + align:start position:0% +related cells +are grid cells in entering cortex okay + + align:start position:0% +are grid cells in entering cortex okay + + + align:start position:0% +are grid cells in entering cortex okay +so this is a slice of the brain like + + align:start position:0% +so this is a slice of the brain like + + + align:start position:0% +so this is a slice of the brain like +this + + align:start position:0% +this + + + align:start position:0% +this +showing the hippocampus this folded up + + align:start position:0% +showing the hippocampus this folded up + + + align:start position:0% +showing the hippocampus this folded up +thing right here + + align:start position:0% +thing right here + + + align:start position:0% +thing right here +an interrental cortex is just + + align:start position:0% +an interrental cortex is just + + + align:start position:0% +an interrental cortex is just +just + + align:start position:0% +just + + + align:start position:0% +just +right next door + + align:start position:0% +right next door + + + align:start position:0% +right next door +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so in internal cortex + + align:start position:0% +so in internal cortex + + + align:start position:0% +so in internal cortex +these things were discovered a little + + align:start position:0% +these things were discovered a little + + + align:start position:0% +these things were discovered a little +around a dozen years ago + + align:start position:0% +around a dozen years ago + + + align:start position:0% +around a dozen years ago +maybe 15 years ago and i'm going to show + + align:start position:0% +maybe 15 years ago and i'm going to show + + + align:start position:0% +maybe 15 years ago and i'm going to show +you a video of a rodent moving around + + align:start position:0% +you a video of a rodent moving around + + + align:start position:0% +you a video of a rodent moving around +his environment + + align:start position:0% +his environment + + + align:start position:0% +his environment +mapping out activity like we saw before + + align:start position:0% +mapping out activity like we saw before + + + align:start position:0% +mapping out activity like we saw before +but now we're in entering cortex and + + align:start position:0% +but now we're in entering cortex and + + + align:start position:0% +but now we're in entering cortex and +this neuron is going to be a grid cell + + align:start position:0% +this neuron is going to be a grid cell + + + align:start position:0% +this neuron is going to be a grid cell +and you'll see why as it moves around in + + align:start position:0% +and you'll see why as it moves around in + + + align:start position:0% +and you'll see why as it moves around in +its space + + align:start position:0% + + + + align:start position:0% + +maybe + + align:start position:0% + + + + align:start position:0% + +come on here we go + + align:start position:0% +come on here we go + + + align:start position:0% +come on here we go +okay so there's the rodent he's moving + + align:start position:0% +okay so there's the rodent he's moving + + + align:start position:0% +okay so there's the rodent he's moving +around that's the tether taking the + + align:start position:0% +around that's the tether taking the + + + align:start position:0% +around that's the tether taking the +neural activity the white dots are every + + align:start position:0% +neural activity the white dots are every + + + align:start position:0% +neural activity the white dots are every +time this one neuron fires we're + + align:start position:0% +time this one neuron fires we're + + + align:start position:0% +time this one neuron fires we're +following one neuron this whole time + + align:start position:0% +following one neuron this whole time + + + align:start position:0% +following one neuron this whole time +and the rodent is moving around sped up + + align:start position:0% +and the rodent is moving around sped up + + + align:start position:0% +and the rodent is moving around sped up +video so you can see this happening and + + align:start position:0% +video so you can see this happening and + + + align:start position:0% +video so you can see this happening and +at first it looks like completely random + + align:start position:0% +at first it looks like completely random + + + align:start position:0% +at first it looks like completely random +but as the rodent keeps migrating around + + align:start position:0% +but as the rodent keeps migrating around + + + align:start position:0% +but as the rodent keeps migrating around +in his space there you start to see that + + align:start position:0% +in his space there you start to see that + + + align:start position:0% +in his space there you start to see that +they're like blobs in there it's not + + align:start position:0% +they're like blobs in there it's not + + + align:start position:0% +they're like blobs in there it's not +totally random they're particular blobs + + align:start position:0% +totally random they're particular blobs + + + align:start position:0% +totally random they're particular blobs +that are clustered + + align:start position:0% +that are clustered + + + align:start position:0% +that are clustered +and oh my god those blobs are organized + + align:start position:0% +and oh my god those blobs are organized + + + align:start position:0% +and oh my god those blobs are organized +in a hexagonal grid + + align:start position:0% +in a hexagonal grid + + + align:start position:0% +in a hexagonal grid +it's a hexagon + + align:start position:0% +it's a hexagon + + + align:start position:0% +it's a hexagon +isn't that awesome that's a grid cell + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% +and + + + align:start position:0% +and +oops there we go we don't need to see it + + align:start position:0% +oops there we go we don't need to see it + + + align:start position:0% +oops there we go we don't need to see it +again + + align:start position:0% +again + + + align:start position:0% +again +so this is a picture of what you just + + align:start position:0% +so this is a picture of what you just + + + align:start position:0% +so this is a picture of what you just +saw the trajectory of the animal and the + + align:start position:0% +saw the trajectory of the animal and the + + + align:start position:0% +saw the trajectory of the animal and the +hot spots uh in that array and here's a + + align:start position:0% +hot spots uh in that array and here's a + + + align:start position:0% +hot spots uh in that array and here's a +kind of smooth mathy version of where + + align:start position:0% +kind of smooth mathy version of where + + + align:start position:0% +kind of smooth mathy version of where +the firing is significant in that space + + align:start position:0% +the firing is significant in that space + + + align:start position:0% +the firing is significant in that space +both showing you hexagonal grid cells + + align:start position:0% +both showing you hexagonal grid cells + + + align:start position:0% +both showing you hexagonal grid cells +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so + + align:start position:0% +so + + + align:start position:0% +so +this is at first glance a very weird + + align:start position:0% +this is at first glance a very weird + + + align:start position:0% +this is at first glance a very weird +thing why would it help to have a um + + align:start position:0% +thing why would it help to have a um + + + align:start position:0% +thing why would it help to have a um +a kind of plate essentially a place + + align:start position:0% +a kind of plate essentially a place + + + align:start position:0% +a kind of plate essentially a place +field that has multiple different places + + align:start position:0% +field that has multiple different places + + + align:start position:0% +field that has multiple different places +that make it fire okay and actually + + align:start position:0% +that make it fire okay and actually + + + align:start position:0% +that make it fire okay and actually +somebody asked before where their place + + align:start position:0% +somebody asked before where their place + + + align:start position:0% +somebody asked before where their place +cells have two hot spots place cells + + align:start position:0% +cells have two hot spots place cells + + + align:start position:0% +cells have two hot spots place cells +generally have one but grid cells as you + + align:start position:0% +generally have one but grid cells as you + + + align:start position:0% +generally have one but grid cells as you +see have many organized in this grid + + align:start position:0% +see have many organized in this grid + + + align:start position:0% +see have many organized in this grid +okay + + align:start position:0% +okay + + + align:start position:0% +okay +um + + align:start position:0% +um + + + align:start position:0% +um +so + + align:start position:0% +so + + + align:start position:0% +so +the the kind of circuitry and math of + + align:start position:0% +the the kind of circuitry and math of + + + align:start position:0% +the the kind of circuitry and math of +this whole system is mind-blowing and + + align:start position:0% +this whole system is mind-blowing and + + + align:start position:0% +this whole system is mind-blowing and +super exciting and the talk that i + + align:start position:0% +super exciting and the talk that i + + + align:start position:0% +super exciting and the talk that i +mentioned yesterday uh was on this topic + + align:start position:0% +mentioned yesterday uh was on this topic + + + align:start position:0% +mentioned yesterday uh was on this topic +and many people are working on this and + + align:start position:0% +and many people are working on this and + + + align:start position:0% +and many people are working on this and +they're working out like really deep + + align:start position:0% +they're working out like really deep + + + align:start position:0% +they're working out like really deep +interesting math about how you can take + + align:start position:0% +interesting math about how you can take + + + align:start position:0% +interesting math about how you can take +these cells how they remain arranged + + align:start position:0% +these cells how they remain arranged + + + align:start position:0% +these cells how they remain arranged +spatially in the brain at multiple + + align:start position:0% +spatially in the brain at multiple + + + align:start position:0% +spatially in the brain at multiple +scales and how you can use them to + + align:start position:0% +scales and how you can use them to + + + align:start position:0% +scales and how you can use them to +do path integration and keep track of + + align:start position:0% +do path integration and keep track of + + + align:start position:0% +do path integration and keep track of +how far you an animal has gone along + + align:start position:0% +how far you an animal has gone along + + + align:start position:0% +how far you an animal has gone along +this trajectory it's a little bit much + + align:start position:0% +this trajectory it's a little bit much + + + align:start position:0% +this trajectory it's a little bit much +for this course but i'll just say the + + align:start position:0% +for this course but i'll just say the + + + align:start position:0% +for this course but i'll just say the +current thinking is + + align:start position:0% +current thinking is + + + align:start position:0% +current thinking is +what these + + align:start position:0% +what these + + + align:start position:0% +what these +what these cells enable us to do is to + + align:start position:0% +what these cells enable us to do is to + + + align:start position:0% +what these cells enable us to do is to +keep track of how far we've gone in each + + align:start position:0% +keep track of how far we've gone in each + + + align:start position:0% +keep track of how far we've gone in each +direction and that's really crucial in + + align:start position:0% +direction and that's really crucial in + + + align:start position:0% +direction and that's really crucial in +navigation we need to know uh where we + + align:start position:0% +navigation we need to know uh where we + + + align:start position:0% +navigation we need to know uh where we +are not just by the landmarks we see we + + align:start position:0% +are not just by the landmarks we see we + + + align:start position:0% +are not just by the landmarks we see we +need to know how far we've gone in a + + align:start position:0% +need to know how far we've gone in a + + + align:start position:0% +need to know how far we've gone in a +given direction and the thought is that + + align:start position:0% +given direction and the thought is that + + + align:start position:0% +given direction and the thought is that +that's the function that these grid + + align:start position:0% +that's the function that these grid + + + align:start position:0% +that's the function that these grid +cells primarily serve in navigation + + align:start position:0% +cells primarily serve in navigation + + + align:start position:0% +cells primarily serve in navigation +um and so that's + + align:start position:0% +um and so that's + + + align:start position:0% +um and so that's +especially important for dead reckoning + + align:start position:0% +especially important for dead reckoning + + + align:start position:0% +especially important for dead reckoning +like integrating you know where you've + + align:start position:0% +like integrating you know where you've + + + align:start position:0% +like integrating you know where you've +gone according to your trajectories okay + + align:start position:0% +gone according to your trajectories okay + + + align:start position:0% +gone according to your trajectories okay +so you also need head direction cells at + + align:start position:0% +so you also need head direction cells at + + + align:start position:0% +so you also need head direction cells at +each point so you can think of the head + + align:start position:0% +each point so you can think of the head + + + align:start position:0% +each point so you can think of the head +direction cells is telling you the + + align:start position:0% +direction cells is telling you the + + + align:start position:0% +direction cells is telling you the +orientation of your vector and the grid + + align:start position:0% +orientation of your vector and the grid + + + align:start position:0% +orientation of your vector and the grid +cells of telling you the magnitude of + + align:start position:0% +cells of telling you the magnitude of + + + align:start position:0% +cells of telling you the magnitude of +the vector of how far you went and you + + align:start position:0% +the vector of how far you went and you + + + align:start position:0% +the vector of how far you went and you +take a whole bunch of those and you + + align:start position:0% +take a whole bunch of those and you + + + align:start position:0% +take a whole bunch of those and you +integrate them and you know where you've + + align:start position:0% +integrate them and you know where you've + + + align:start position:0% +integrate them and you know where you've +gone from your starting point + + align:start position:0% +gone from your starting point + + + align:start position:0% +gone from your starting point +and lots of animals do all that math in + + align:start position:0% +and lots of animals do all that math in + + + align:start position:0% +and lots of animals do all that math in +their head like it's pretty complicated + + align:start position:0% +their head like it's pretty complicated + + + align:start position:0% +their head like it's pretty complicated +integrals right but they all do + + align:start position:0% +integrals right but they all do + + + align:start position:0% +integrals right but they all do +that um okay so this is super awesome + + align:start position:0% +that um okay so this is super awesome + + + align:start position:0% +that um okay so this is super awesome +work and uh fittingly the 2014 nobel + + align:start position:0% +work and uh fittingly the 2014 nobel + + + align:start position:0% +work and uh fittingly the 2014 nobel +prize was awarded to + + align:start position:0% +prize was awarded to + + + align:start position:0% +prize was awarded to +um + + align:start position:0% +um + + + align:start position:0% +um +the the mosers a husband then husband + + align:start position:0% +the the mosers a husband then husband + + + align:start position:0% +the the mosers a husband then husband +wife team + + align:start position:0% +wife team + + + align:start position:0% +wife team +who discovered the grid cells uh and for + + align:start position:0% +who discovered the grid cells uh and for + + + align:start position:0% +who discovered the grid cells uh and for +and also to john o'keefe who discovered + + align:start position:0% +and also to john o'keefe who discovered + + + align:start position:0% +and also to john o'keefe who discovered +place cells uh decades earlier + + align:start position:0% +place cells uh decades earlier + + + align:start position:0% +place cells uh decades earlier +um and it's um it's a super exciting + + align:start position:0% +um and it's um it's a super exciting + + + align:start position:0% +um and it's um it's a super exciting +line of work and continuing continuing + + align:start position:0% +line of work and continuing continuing + + + align:start position:0% +line of work and continuing continuing +to be very exciting one okay so so far + + align:start position:0% +to be very exciting one okay so so far + + + align:start position:0% +to be very exciting one okay so so far +we've talked about place cells in the + + align:start position:0% +we've talked about place cells in the + + + align:start position:0% +we've talked about place cells in the +hippocampus direction cells in the + + align:start position:0% +hippocampus direction cells in the + + + align:start position:0% +hippocampus direction cells in the +subiculum and lots of other places + + align:start position:0% +subiculum and lots of other places + + + align:start position:0% +subiculum and lots of other places +and end to rhino grid cells in enter + + align:start position:0% +and end to rhino grid cells in enter + + + align:start position:0% +and end to rhino grid cells in enter +rhino cortex and this is just a + + align:start position:0% +rhino cortex and this is just a + + + align:start position:0% +rhino cortex and this is just a +schematic diagram of where those + + align:start position:0% +schematic diagram of where those + + + align:start position:0% +schematic diagram of where those +locations are the anatomy is complicated + + align:start position:0% +locations are the anatomy is complicated + + + align:start position:0% +locations are the anatomy is complicated +and you don't need to know it no they're + + align:start position:0% +and you don't need to know it no they're + + + align:start position:0% +and you don't need to know it no they're +all sort of in the hippocampus and it's + + align:start position:0% +all sort of in the hippocampus and it's + + + align:start position:0% +all sort of in the hippocampus and it's +neighboring structures that's good + + align:start position:0% +neighboring structures that's good + + + align:start position:0% +neighboring structures that's good +enough for for here + + align:start position:0% + + + + align:start position:0% + +well okay know that the grid cells are + + align:start position:0% +well okay know that the grid cells are + + + align:start position:0% +well okay know that the grid cells are +in internal cortex and the place cells + + align:start position:0% +in internal cortex and the place cells + + + align:start position:0% +in internal cortex and the place cells +are in hippocampus that's worth knowing + + align:start position:0% +are in hippocampus that's worth knowing + + + align:start position:0% +are in hippocampus that's worth knowing +okay + + align:start position:0% +okay + + + align:start position:0% +okay +direction cells are kind of all over + + align:start position:0% +direction cells are kind of all over + + + align:start position:0% +direction cells are kind of all over +um + + align:start position:0% +um + + + align:start position:0% +um +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so + + align:start position:0% +so + + + align:start position:0% +so +that's cool but there's one more cool + + align:start position:0% +that's cool but there's one more cool + + + align:start position:0% +that's cool but there's one more cool +kind of cell actually there's several + + align:start position:0% +kind of cell actually there's several + + + align:start position:0% +kind of cell actually there's several +more the new one a new one i never heard + + align:start position:0% +more the new one a new one i never heard + + + align:start position:0% +more the new one a new one i never heard +of was reported in this job talk + + align:start position:0% +of was reported in this job talk + + + align:start position:0% +of was reported in this job talk +yesterday but we won't go there we'll + + align:start position:0% +yesterday but we won't go there we'll + + + align:start position:0% +yesterday but we won't go there we'll +try to keep it simple uh another well + + align:start position:0% +try to keep it simple uh another well + + + align:start position:0% +try to keep it simple uh another well +established one is called a border cell + + align:start position:0% +established one is called a border cell + + + align:start position:0% +established one is called a border cell +okay so this is the these are the place + + align:start position:0% +okay so this is the these are the place + + + align:start position:0% +okay so this is the these are the place +fields of three different neurons + + align:start position:0% +fields of three different neurons + + + align:start position:0% +fields of three different neurons +from an animal + + align:start position:0% +from an animal + + + align:start position:0% +from an animal +moving around in this space + + align:start position:0% +moving around in this space + + + align:start position:0% +moving around in this space +okay so you see how these are very + + align:start position:0% +okay so you see how these are very + + + align:start position:0% +okay so you see how these are very +interesting kind of place fields they're + + align:start position:0% +interesting kind of place fields they're + + + align:start position:0% +interesting kind of place fields they're +not just like a nice round blob they + + align:start position:0% +not just like a nice round blob they + + + align:start position:0% +not just like a nice round blob they +stretch around a whole border of the + + align:start position:0% +stretch around a whole border of the + + + align:start position:0% +stretch around a whole border of the +animal's environment + + align:start position:0% +animal's environment + + + align:start position:0% +animal's environment +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so does that make you think of anything + + align:start position:0% +so does that make you think of anything + + + align:start position:0% +so does that make you think of anything +does that ring any bells with other + + align:start position:0% +does that ring any bells with other + + + align:start position:0% +does that ring any bells with other +stuff we've talked about in here + + align:start position:0% + + + + align:start position:0% + +right think we've talked a bunch about + + align:start position:0% +right think we've talked a bunch about + + + align:start position:0% +right think we've talked a bunch about +how the parahippocampal place area cares + + align:start position:0% +how the parahippocampal place area cares + + + align:start position:0% +how the parahippocampal place area cares +about the shape of space around you + + align:start position:0% +about the shape of space around you + + + align:start position:0% +about the shape of space around you +right well you might think that you'd + + align:start position:0% +right well you might think that you'd + + + align:start position:0% +right well you might think that you'd +really want to have awareness of where + + align:start position:0% +really want to have awareness of where + + + align:start position:0% +really want to have awareness of where +you are with respect to navigational + + align:start position:0% +you are with respect to navigational + + + align:start position:0% +you are with respect to navigational +barriers + + align:start position:0% +barriers + + + align:start position:0% +barriers +it turns out border cells respond not + + align:start position:0% +it turns out border cells respond not + + + align:start position:0% +it turns out border cells respond not +just to walls if you put a rodent in an + + align:start position:0% +just to walls if you put a rodent in an + + + align:start position:0% +just to walls if you put a rodent in an +environment where there's a cliff they + + align:start position:0% +environment where there's a cliff they + + + align:start position:0% +environment where there's a cliff they +can't go off the border cells also + + align:start position:0% +can't go off the border cells also + + + align:start position:0% +can't go off the border cells also +respond to the edge of that cliff okay + + align:start position:0% +respond to the edge of that cliff okay + + + align:start position:0% +respond to the edge of that cliff okay +so any navigational barrier basically + + align:start position:0% +so any navigational barrier basically + + + align:start position:0% +so any navigational barrier basically +telling you where you are with respect + + align:start position:0% +telling you where you are with respect + + + align:start position:0% +telling you where you are with respect +to navigational barriers + + align:start position:0% +to navigational barriers + + + align:start position:0% +to navigational barriers +okay + + align:start position:0% +okay + + + align:start position:0% +okay +okay + + align:start position:0% +okay + + + align:start position:0% +okay +all right + + align:start position:0% +all right + + + align:start position:0% +all right +and blah blah blah okay + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +as i mentioned in the last lecture when + + align:start position:0% +as i mentioned in the last lecture when + + + align:start position:0% +as i mentioned in the last lecture when +we talked about the para hippocampal + + align:start position:0% +we talked about the para hippocampal + + + align:start position:0% +we talked about the para hippocampal +place area the shape of space around you + + align:start position:0% +place area the shape of space around you + + + align:start position:0% +place area the shape of space around you +has this kind of privileged role in many + + align:start position:0% +has this kind of privileged role in many + + + align:start position:0% +has this kind of privileged role in many +aspects of navigation + + align:start position:0% +aspects of navigation + + + align:start position:0% +aspects of navigation +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so + + align:start position:0% +so + + + align:start position:0% +so +now we're going to talk about this + + align:start position:0% +now we're going to talk about this + + + align:start position:0% +now we're going to talk about this +problem of reorienting or regaining your + + align:start position:0% +problem of reorienting or regaining your + + + align:start position:0% +problem of reorienting or regaining your +um your sense of direction once you've + + align:start position:0% +um your sense of direction once you've + + + align:start position:0% +um your sense of direction once you've +been disoriented + + align:start position:0% +been disoriented + + + align:start position:0% +been disoriented +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and so + + align:start position:0% +and so + + + align:start position:0% +and so +um + + align:start position:0% +um + + + align:start position:0% +um +again i mentioned this before but just + + align:start position:0% +again i mentioned this before but just + + + align:start position:0% +again i mentioned this before but just +to give you in the give you the + + align:start position:0% +to give you in the give you the + + + align:start position:0% +to give you in the give you the +intuition of what we're talking about + + align:start position:0% +intuition of what we're talking about + + + align:start position:0% +intuition of what we're talking about +here + + align:start position:0% +here + + + align:start position:0% +here +you come up from the subway in manhattan + + align:start position:0% +you come up from the subway in manhattan + + + align:start position:0% +you come up from the subway in manhattan +or any other environment that you that's + + align:start position:0% +or any other environment that you that's + + + align:start position:0% +or any other environment that you that's +rectilinear that you know + + align:start position:0% +rectilinear that you know + + + align:start position:0% +rectilinear that you know +and you know which stop you're coming at + + align:start position:0% +and you know which stop you're coming at + + + align:start position:0% +and you know which stop you're coming at +up at so you kind of know where you are + + align:start position:0% +up at so you kind of know where you are + + + align:start position:0% +up at so you kind of know where you are +but you come out and you don't know + + align:start position:0% +but you come out and you don't know + + + align:start position:0% +but you come out and you don't know +which way to head right you don't know + + align:start position:0% +which way to head right you don't know + + + align:start position:0% +which way to head right you don't know +which way is which + + align:start position:0% +which way is which + + + align:start position:0% +which way is which +all right + + align:start position:0% +all right + + + align:start position:0% +all right +so that's a modern version of a classic + + align:start position:0% +so that's a modern version of a classic + + + align:start position:0% +so that's a modern version of a classic +problem that animals face in their + + align:start position:0% +problem that animals face in their + + + align:start position:0% +problem that animals face in their +environment they may know where they are + + align:start position:0% +environment they may know where they are + + + align:start position:0% +environment they may know where they are +but that doesn't tell them which way + + align:start position:0% +but that doesn't tell them which way + + + align:start position:0% +but that doesn't tell them which way +they're facing + + align:start position:0% +they're facing + + + align:start position:0% +they're facing +so just to be really concrete about this + + align:start position:0% +so just to be really concrete about this + + + align:start position:0% +so just to be really concrete about this +so here's an aerial view of a person + + align:start position:0% +so here's an aerial view of a person + + + align:start position:0% +so here's an aerial view of a person +you're standing here + + align:start position:0% +you're standing here + + + align:start position:0% +you're standing here +you have a cognitive map in your mind + + align:start position:0% +you have a cognitive map in your mind + + + align:start position:0% +you have a cognitive map in your mind +and your place cells are telling you + + align:start position:0% +and your place cells are telling you + + + align:start position:0% +and your place cells are telling you +your location in that map okay so you + + align:start position:0% +your location in that map okay so you + + + align:start position:0% +your location in that map okay so you +know where you are in that map + + align:start position:0% +know where you are in that map + + + align:start position:0% +know where you are in that map +but to you and you're looking down a + + align:start position:0% +but to you and you're looking down a + + + align:start position:0% +but to you and you're looking down a +street so you know that you're oriented + + align:start position:0% +street so you know that you're oriented + + + align:start position:0% +street so you know that you're oriented +with respect to some external + + align:start position:0% +with respect to some external + + + align:start position:0% +with respect to some external +axis like this + + align:start position:0% +axis like this + + + align:start position:0% +axis like this +but you don't know + + align:start position:0% +but you don't know + + + align:start position:0% +but you don't know +how your mental map should be aligned + + align:start position:0% +how your mental map should be aligned + + + align:start position:0% +how your mental map should be aligned +with that street + + align:start position:0% +with that street + + + align:start position:0% +with that street +are you facing + + align:start position:0% +are you facing + + + align:start position:0% +are you facing +like this facing north + + align:start position:0% +like this facing north + + + align:start position:0% +like this facing north +in manhattan + + align:start position:0% +in manhattan + + + align:start position:0% +in manhattan +or + + align:start position:0% +or + + + align:start position:0% +or +are you facing south + + align:start position:0% +are you facing south + + + align:start position:0% +are you facing south +right + + align:start position:0% +right + + + align:start position:0% +right +so that's the problem of reorientation + + align:start position:0% +so that's the problem of reorientation + + + align:start position:0% +so that's the problem of reorientation +is figuring out your particular + + align:start position:0% +is figuring out your particular + + + align:start position:0% +is figuring out your particular +orientation not just your location but + + align:start position:0% +orientation not just your location but + + + align:start position:0% +orientation not just your location but +which way you're facing in a known + + align:start position:0% +which way you're facing in a known + + + align:start position:0% +which way you're facing in a known +environment okay and we've all faced + + align:start position:0% +environment okay and we've all faced + + + align:start position:0% +environment okay and we've all faced +some version of this presumably at some + + align:start position:0% +some version of this presumably at some + + + align:start position:0% +some version of this presumably at some +point + + align:start position:0% +point + + + align:start position:0% +point +and it's annoying it takes a while to + + align:start position:0% +and it's annoying it takes a while to + + + align:start position:0% +and it's annoying it takes a while to +figure out and then i don't know if + + align:start position:0% +figure out and then i don't know if + + + align:start position:0% +figure out and then i don't know if +anybody's had this experience i've had + + align:start position:0% +anybody's had this experience i've had + + + align:start position:0% +anybody's had this experience i've had +it only in manhattan because that's + + align:start position:0% +it only in manhattan because that's + + + align:start position:0% +it only in manhattan because that's +where this arises for me but i'm sure + + align:start position:0% +where this arises for me but i'm sure + + + align:start position:0% +where this arises for me but i'm sure +there are other locations where you come + + align:start position:0% +there are other locations where you come + + + align:start position:0% +there are other locations where you come +up and you think you're going one way + + align:start position:0% +up and you think you're going one way + + + align:start position:0% +up and you think you're going one way +and then all of a sudden like your whole + + align:start position:0% +and then all of a sudden like your whole + + + align:start position:0% +and then all of a sudden like your whole +like it's like your whole mental map + + align:start position:0% +like it's like your whole mental map + + + align:start position:0% +like it's like your whole mental map +goes kaboom + + align:start position:0% +goes kaboom + + + align:start position:0% +goes kaboom +so how many people have had that + + align:start position:0% +so how many people have had that + + + align:start position:0% +so how many people have had that +experience like it's very sudden and + + align:start position:0% +experience like it's very sudden and + + + align:start position:0% +experience like it's very sudden and +punk date yeah + + align:start position:0% +punk date yeah + + + align:start position:0% +punk date yeah +turns out that when that happens all of + + align:start position:0% +turns out that when that happens all of + + + align:start position:0% +turns out that when that happens all of +your neurons flip together in unison + + align:start position:0% +your neurons flip together in unison + + + align:start position:0% +your neurons flip together in unison +like they're all in cahoots they have + + align:start position:0% +like they're all in cahoots they have + + + align:start position:0% +like they're all in cahoots they have +one version of this when you have that + + align:start position:0% +one version of this when you have that + + + align:start position:0% +one version of this when you have that +experience it's because they're all + + align:start position:0% +experience it's because they're all + + + align:start position:0% +experience it's because they're all +flipping together and i'll show you some + + align:start position:0% +flipping together and i'll show you some + + + align:start position:0% +flipping together and i'll show you some +data on that in a second + + align:start position:0% +data on that in a second + + + align:start position:0% +data on that in a second +okay all right + + align:start position:0% +okay all right + + + align:start position:0% +okay all right +so there's a very evolutionary old + + align:start position:0% +so there's a very evolutionary old + + + align:start position:0% +so there's a very evolutionary old +system for solving just this problem and + + align:start position:0% +system for solving just this problem and + + + align:start position:0% +system for solving just this problem and +it's a wonderful little kind of piece of + + align:start position:0% +it's a wonderful little kind of piece of + + + align:start position:0% +it's a wonderful little kind of piece of +the literature that i'm going to spend a + + align:start position:0% +the literature that i'm going to spend a + + + align:start position:0% +the literature that i'm going to spend a +couple minutes on because it's so + + align:start position:0% +couple minutes on because it's so + + + align:start position:0% +couple minutes on because it's so +classic + + align:start position:0% +classic + + + align:start position:0% +classic +and so cool + + align:start position:0% +and so cool + + + align:start position:0% +and so cool +and this started with work by randy + + align:start position:0% +and this started with work by randy + + + align:start position:0% +and this started with work by randy +gallistail in the 1980s and so what he + + align:start position:0% +gallistail in the 1980s and so what he + + + align:start position:0% +gallistail in the 1980s and so what he +did was he studied this problem of + + align:start position:0% +did was he studied this problem of + + + align:start position:0% +did was he studied this problem of +reorientation that is figuring out your + + align:start position:0% +reorientation that is figuring out your + + + align:start position:0% +reorientation that is figuring out your +orientation in a known environment once + + align:start position:0% +orientation in a known environment once + + + align:start position:0% +orientation in a known environment once +you've been disoriented okay it's a very + + align:start position:0% +you've been disoriented okay it's a very + + + align:start position:0% +you've been disoriented okay it's a very +particular aspect of the problem of + + align:start position:0% +particular aspect of the problem of + + + align:start position:0% +particular aspect of the problem of +navigation + + align:start position:0% +navigation + + + align:start position:0% +navigation +so he put rats in a rectangular + + align:start position:0% +so he put rats in a rectangular + + + align:start position:0% +so he put rats in a rectangular +environment and he had them explore the + + align:start position:0% +environment and he had them explore the + + + align:start position:0% +environment and he had them explore the +environment + + align:start position:0% +environment + + + align:start position:0% +environment +and then he hid some + + align:start position:0% +and then he hid some + + + align:start position:0% +and then he hid some +rat relevant thing like a little piece + + align:start position:0% +rat relevant thing like a little piece + + + align:start position:0% +rat relevant thing like a little piece +of food say a chocolate chip in that + + align:start position:0% +of food say a chocolate chip in that + + + align:start position:0% +of food say a chocolate chip in that +corner okay rat sees that happen rad is + + align:start position:0% +corner okay rat sees that happen rad is + + + align:start position:0% +corner okay rat sees that happen rad is +interested take rat out of box before + + align:start position:0% +interested take rat out of box before + + + align:start position:0% +interested take rat out of box before +they get to go take the the chocolate + + align:start position:0% +they get to go take the the chocolate + + + align:start position:0% +they get to go take the the chocolate +chip + + align:start position:0% +chip + + + align:start position:0% +chip +and then you disorient the rat you don't + + align:start position:0% +and then you disorient the rat you don't + + + align:start position:0% +and then you disorient the rat you don't +grab them by the tail and swing them + + align:start position:0% +grab them by the tail and swing them + + + align:start position:0% +grab them by the tail and swing them +around but you do some slower version + + align:start position:0% +around but you do some slower version + + + align:start position:0% +around but you do some slower version +you don't want to make them sick you do + + align:start position:0% +you don't want to make them sick you do + + + align:start position:0% +you don't want to make them sick you do +some slower version of that so they've + + align:start position:0% +some slower version of that so they've + + + align:start position:0% +some slower version of that so they've +lost track of which way they're facing + + align:start position:0% +lost track of which way they're facing + + + align:start position:0% +lost track of which way they're facing +okay + + align:start position:0% +okay + + + align:start position:0% +okay +now you put them in a new box new box + + align:start position:0% +now you put them in a new box new box + + + align:start position:0% +now you put them in a new box new box +because you don't want the smell to + + align:start position:0% +because you don't want the smell to + + + align:start position:0% +because you don't want the smell to +still be there new box + + align:start position:0% +still be there new box + + + align:start position:0% +still be there new box +and you see which way the rat goes + + align:start position:0% +and you see which way the rat goes + + + align:start position:0% +and you see which way the rat goes +and you find that the rat goes 50 50 to + + align:start position:0% +and you find that the rat goes 50 50 to + + + align:start position:0% +and you find that the rat goes 50 50 to +those two corners + + align:start position:0% +those two corners + + + align:start position:0% +those two corners +what does that mean the rat has encoded + + align:start position:0% + + + + align:start position:0% + +he doesn't go randomly to any corner + + align:start position:0% +he doesn't go randomly to any corner + + + align:start position:0% +he doesn't go randomly to any corner +he goes to corners you know it was in a + + align:start position:0% +he goes to corners you know it was in a + + + align:start position:0% +he goes to corners you know it was in a +corner he doesn't go randomly to any + + align:start position:0% +corner he doesn't go randomly to any + + + align:start position:0% +corner he doesn't go randomly to any +corner yeah + + align:start position:0% +corner yeah + + + align:start position:0% +corner yeah +i'm jack i'm sorry + + align:start position:0% + + + + align:start position:0% + +like it's specifically in + + align:start position:0% +like it's specifically in + + + align:start position:0% +like it's specifically in +like one of these directions + + align:start position:0% + + + + align:start position:0% + +you've got to say a little more than + + align:start position:0% +you've got to say a little more than + + + align:start position:0% +you've got to say a little more than +that what's to the left what's different + + align:start position:0% +that what's to the left what's different + + + align:start position:0% +that what's to the left what's different +about those two corners and the other + + align:start position:0% +about those two corners and the other + + + align:start position:0% +about those two corners and the other +two yeah isabel well he's looking at the + + align:start position:0% +two yeah isabel well he's looking at the + + + align:start position:0% +two yeah isabel well he's looking at the +shape of the room + + align:start position:0% +shape of the room + + + align:start position:0% +shape of the room +there's two longer walls and two + + align:start position:0% +there's two longer walls and two + + + align:start position:0% +there's two longer walls and two +shoulder walls he recognizes that he's + + align:start position:0% +shoulder walls he recognizes that he's + + + align:start position:0% +shoulder walls he recognizes that he's +basically involved he has to go to what + + align:start position:0% +basically involved he has to go to what + + + align:start position:0% +basically involved he has to go to what +looks like the right complaint + + align:start position:0% +looks like the right complaint + + + align:start position:0% +looks like the right complaint +exactly he has to have encoded the axis + + align:start position:0% +exactly he has to have encoded the axis + + + align:start position:0% +exactly he has to have encoded the axis +um + + align:start position:0% +um + + + align:start position:0% +um +the the orient the fact that the the + + align:start position:0% +the the orient the fact that the the + + + align:start position:0% +the the orient the fact that the the +room has a is longer on one axis than + + align:start position:0% +room has a is longer on one axis than + + + align:start position:0% +room has a is longer on one axis than +another + + align:start position:0% +another + + + align:start position:0% +another +and he's essentially encoded that + + align:start position:0% +and he's essentially encoded that + + + align:start position:0% +and he's essentially encoded that +chocolate chip was on the right side of + + align:start position:0% +chocolate chip was on the right side of + + + align:start position:0% +chocolate chip was on the right side of +the long wall or the left side of the + + align:start position:0% +the long wall or the left side of the + + + align:start position:0% +the long wall or the left side of the +short wall and both of those corners are + + align:start position:0% +short wall and both of those corners are + + + align:start position:0% +short wall and both of those corners are +consistent with that that's why he goes + + align:start position:0% +consistent with that that's why he goes + + + align:start position:0% +consistent with that that's why he goes +50 50 to them + + align:start position:0% +50 50 to them + + + align:start position:0% +50 50 to them +he can't go 100 of the time to the right + + align:start position:0% +he can't go 100 of the time to the right + + + align:start position:0% +he can't go 100 of the time to the right +corner because he has no information + + align:start position:0% +corner because he has no information + + + align:start position:0% +corner because he has no information +that would tell him that in this + + align:start position:0% +that would tell him that in this + + + align:start position:0% +that would tell him that in this +experiment okay everybody clear so it + + align:start position:0% +experiment okay everybody clear so it + + + align:start position:0% +experiment okay everybody clear so it +tells you he learned where the thing is + + align:start position:0% +tells you he learned where the thing is + + + align:start position:0% +tells you he learned where the thing is +with respect to the shape of the room + + align:start position:0% +with respect to the shape of the room + + + align:start position:0% +with respect to the shape of the room +and its particular aspect ratio okay + + align:start position:0% +and its particular aspect ratio okay + + + align:start position:0% +and its particular aspect ratio okay +so now the plot thickens + + align:start position:0% +so now the plot thickens + + + align:start position:0% +so now the plot thickens +and now they repeat the experiment but + + align:start position:0% +and now they repeat the experiment but + + + align:start position:0% +and now they repeat the experiment but +this time they make some very rat + + align:start position:0% +this time they make some very rat + + + align:start position:0% +this time they make some very rat +salient asymmetry over here you make a + + align:start position:0% +salient asymmetry over here you make a + + + align:start position:0% +salient asymmetry over here you make a +color and a texture + + align:start position:0% +color and a texture + + + align:start position:0% +color and a texture +and you make other things to make this + + align:start position:0% +and you make other things to make this + + + align:start position:0% +and you make other things to make this +wall very saliently different + + align:start position:0% +wall very saliently different + + + align:start position:0% +wall very saliently different +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so you would think the rat motivated to + + align:start position:0% +so you would think the rat motivated to + + + align:start position:0% +so you would think the rat motivated to +find the chocolate chip would now go 100 + + align:start position:0% +find the chocolate chip would now go 100 + + + align:start position:0% +find the chocolate chip would now go 100 +to that corner when we put them in the + + align:start position:0% +to that corner when we put them in the + + + align:start position:0% +to that corner when we put them in the +new box with the same landmark queue + + align:start position:0% +new box with the same landmark queue + + + align:start position:0% +new box with the same landmark queue +over there + + align:start position:0% +over there + + + align:start position:0% +over there +but no the rat goes 50 50 to the same + + align:start position:0% +but no the rat goes 50 50 to the same + + + align:start position:0% +but no the rat goes 50 50 to the same +two corners + + align:start position:0% +two corners + + + align:start position:0% +two corners +and in control experiments many + + align:start position:0% +and in control experiments many + + + align:start position:0% +and in control experiments many +controlled conditions you can show and + + align:start position:0% +controlled conditions you can show and + + + align:start position:0% +controlled conditions you can show and +i'll show you one in a moment the rat + + align:start position:0% +i'll show you one in a moment the rat + + + align:start position:0% +i'll show you one in a moment the rat +absolutely knows about this wall he's + + align:start position:0% +absolutely knows about this wall he's + + + align:start position:0% +absolutely knows about this wall he's +encoded the presence of that asymmetric + + align:start position:0% +encoded the presence of that asymmetric + + + align:start position:0% +encoded the presence of that asymmetric +wall so he has the information that + + align:start position:0% +wall so he has the information that + + + align:start position:0% +wall so he has the information that +should enable him to break the symmetry + + align:start position:0% +should enable him to break the symmetry + + + align:start position:0% +should enable him to break the symmetry +but he doesn't use it + + align:start position:0% +but he doesn't use it + + + align:start position:0% +but he doesn't use it +that's weird you should be surprised + + align:start position:0% +that's weird you should be surprised + + + align:start position:0% +that's weird you should be surprised +okay + + align:start position:0% +okay + + + align:start position:0% +okay +everybody get why that's weird he could + + align:start position:0% +everybody get why that's weird he could + + + align:start position:0% +everybody get why that's weird he could +have solved this one perfectly this time + + align:start position:0% +have solved this one perfectly this time + + + align:start position:0% +have solved this one perfectly this time +he has the information he's not using + + align:start position:0% +he has the information he's not using + + + align:start position:0% +he has the information he's not using +that information + + align:start position:0% +that information + + + align:start position:0% +that information +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so + + align:start position:0% +so + + + align:start position:0% +so +that's weird + + align:start position:0% +that's weird + + + align:start position:0% +that's weird +but then liz spelke and her colleagues + + align:start position:0% +but then liz spelke and her colleagues + + + align:start position:0% +but then liz spelke and her colleagues +came along 10 years later and said let's + + align:start position:0% +came along 10 years later and said let's + + + align:start position:0% +came along 10 years later and said let's +try this with infants + + align:start position:0% +try this with infants + + + align:start position:0% +try this with infants +and so they did the infant version where + + align:start position:0% +and so they did the infant version where + + + align:start position:0% +and so they did the infant version where +you put the infant in a room with a + + align:start position:0% +you put the infant in a room with a + + + align:start position:0% +you put the infant in a room with a +symmetrical with a um + + align:start position:0% +symmetrical with a um + + + align:start position:0% +symmetrical with a um +in a rectangular room and you hide the + + align:start position:0% +in a rectangular room and you hide the + + + align:start position:0% +in a rectangular room and you hide the +doors so the infant doesn't have any uh + + align:start position:0% +doors so the infant doesn't have any uh + + + align:start position:0% +doors so the infant doesn't have any uh +cues other than the shape of the room + + align:start position:0% +cues other than the shape of the room + + + align:start position:0% +cues other than the shape of the room +um um 18 to 24 month old infants + + align:start position:0% +um um 18 to 24 month old infants + + + align:start position:0% +um um 18 to 24 month old infants +um and then uh you hide a toy in a + + align:start position:0% +um and then uh you hide a toy in a + + + align:start position:0% +um and then uh you hide a toy in a +corner and you see what the infant does + + align:start position:0% +corner and you see what the infant does + + + align:start position:0% +corner and you see what the infant does +and uh oh actually what you do with the + + align:start position:0% +and uh oh actually what you do with the + + + align:start position:0% +and uh oh actually what you do with the +infant is you make this wall really + + align:start position:0% +infant is you make this wall really + + + align:start position:0% +infant is you make this wall really +salient in all kinds of ways you in one + + align:start position:0% +salient in all kinds of ways you in one + + + align:start position:0% +salient in all kinds of ways you in one +case that was red velvet and they first + + align:start position:0% +case that was red velvet and they first + + + align:start position:0% +case that was red velvet and they first +showed the and these aren't like these + + align:start position:0% +showed the and these aren't like these + + + align:start position:0% +showed the and these aren't like these +are i guess toddlers right they first + + align:start position:0% +are i guess toddlers right they first + + + align:start position:0% +are i guess toddlers right they first +show them that when you knock on the red + + align:start position:0% +show them that when you knock on the red + + + align:start position:0% +show them that when you knock on the red +wall music happens + + align:start position:0% +wall music happens + + + align:start position:0% +wall music happens +totally cool riveting for a little kid + + align:start position:0% +totally cool riveting for a little kid + + + align:start position:0% +totally cool riveting for a little kid +they totally get it they know all about + + align:start position:0% +they totally get it they know all about + + + align:start position:0% +they totally get it they know all about +the music wall very salient to them + + align:start position:0% +the music wall very salient to them + + + align:start position:0% +the music wall very salient to them +nonetheless you put them in this + + align:start position:0% +nonetheless you put them in this + + + align:start position:0% +nonetheless you put them in this +experiment and they behave just like + + align:start position:0% +experiment and they behave just like + + + align:start position:0% +experiment and they behave just like +rodents they go 50 50 to the two corners + + align:start position:0% +rodents they go 50 50 to the two corners + + + align:start position:0% +rodents they go 50 50 to the two corners +even though they notice the red music + + align:start position:0% +even though they notice the red music + + + align:start position:0% +even though they notice the red music +wall and it could have solved the + + align:start position:0% +wall and it could have solved the + + + align:start position:0% +wall and it could have solved the +problem for them perfectly and they were + + align:start position:0% +problem for them perfectly and they were + + + align:start position:0% +problem for them perfectly and they were +motivated they didn't use the + + align:start position:0% +motivated they didn't use the + + + align:start position:0% +motivated they didn't use the +information + + align:start position:0% +information + + + align:start position:0% +information +everybody get why that's + + align:start position:0% +everybody get why that's + + + align:start position:0% +everybody get why that's +kind of interesting and kind of + + align:start position:0% +kind of interesting and kind of + + + align:start position:0% +kind of interesting and kind of +surprising + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +now you might say okay rodents infants + + align:start position:0% +now you might say okay rodents infants + + + align:start position:0% +now you might say okay rodents infants +they're dummies + + align:start position:0% +they're dummies + + + align:start position:0% +they're dummies +uh we wouldn't do that + + align:start position:0% +uh we wouldn't do that + + + align:start position:0% +uh we wouldn't do that +us smart adult humans would we + + align:start position:0% +us smart adult humans would we + + + align:start position:0% +us smart adult humans would we +but oh yes you would + + align:start position:0% +but oh yes you would + + + align:start position:0% +but oh yes you would +under certain circumstances + + align:start position:0% +under certain circumstances + + + align:start position:0% +under certain circumstances +if we tied up your language system + + align:start position:0% +if we tied up your language system + + + align:start position:0% +if we tied up your language system +and there's lots of ways of doing that + + align:start position:0% +and there's lots of ways of doing that + + + align:start position:0% +and there's lots of ways of doing that +one way is called shadowing so it's kind + + align:start position:0% +one way is called shadowing so it's kind + + + align:start position:0% +one way is called shadowing so it's kind +of like simultaneous translation but you + + align:start position:0% +of like simultaneous translation but you + + + align:start position:0% +of like simultaneous translation but you +don't translate try this sometime i do + + align:start position:0% +don't translate try this sometime i do + + + align:start position:0% +don't translate try this sometime i do +this occasionally when i'm bored in my + + align:start position:0% +this occasionally when i'm bored in my + + + align:start position:0% +this occasionally when i'm bored in my +car just because it's amusingly + + align:start position:0% +car just because it's amusingly + + + align:start position:0% +car just because it's amusingly +difficult turn on the radio listen to + + align:start position:0% +difficult turn on the radio listen to + + + align:start position:0% +difficult turn on the radio listen to +somebody talking and just repeat + + align:start position:0% +somebody talking and just repeat + + + align:start position:0% +somebody talking and just repeat +everything they say + + align:start position:0% +everything they say + + + align:start position:0% +everything they say +after they say it right + + align:start position:0% +after they say it right + + + align:start position:0% +after they say it right +i'm not even translating it's still + + align:start position:0% +i'm not even translating it's still + + + align:start position:0% +i'm not even translating it's still +demanding right so you have to you have + + align:start position:0% +demanding right so you have to you have + + + align:start position:0% +demanding right so you have to you have +to be listening and producing + + align:start position:0% +to be listening and producing + + + align:start position:0% +to be listening and producing +right okay a little running thing okay + + align:start position:0% +right okay a little running thing okay + + + align:start position:0% +right okay a little running thing okay +so that's called verbal shadowing and + + align:start position:0% +so that's called verbal shadowing and + + + align:start position:0% +so that's called verbal shadowing and +it's an established way to really like + + align:start position:0% +it's an established way to really like + + + align:start position:0% +it's an established way to really like +tie up your language system and kind of + + align:start position:0% +tie up your language system and kind of + + + align:start position:0% +tie up your language system and kind of +take it offline so you can't really use + + align:start position:0% +take it offline so you can't really use + + + align:start position:0% +take it offline so you can't really use +it + + align:start position:0% +it + + + align:start position:0% +it +when you do this experiment on human + + align:start position:0% +when you do this experiment on human + + + align:start position:0% +when you do this experiment on human +adults + + align:start position:0% +adults + + + align:start position:0% +adults +if they're verbally shadowing and their + + align:start position:0% +if they're verbally shadowing and their + + + align:start position:0% +if they're verbally shadowing and their +language system is tied up they behave + + align:start position:0% +language system is tied up they behave + + + align:start position:0% +language system is tied up they behave +just like rodents and infants that is + + align:start position:0% +just like rodents and infants that is + + + align:start position:0% +just like rodents and infants that is +they use the shape of the space + + align:start position:0% +they use the shape of the space + + + align:start position:0% +they use the shape of the space +but they don't use salient landmarks + + align:start position:0% +but they don't use salient landmarks + + + align:start position:0% +but they don't use salient landmarks +that could help them solve it perfectly + + align:start position:0% +that could help them solve it perfectly + + + align:start position:0% +that could help them solve it perfectly +they go 50 50 to the two corners + + align:start position:0% +they go 50 50 to the two corners + + + align:start position:0% +they go 50 50 to the two corners +they become rats and infants + + align:start position:0% +they become rats and infants + + + align:start position:0% +they become rats and infants +we become rats and infants + + align:start position:0% +we become rats and infants + + + align:start position:0% +we become rats and infants +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so liz spelke has spun a whole + + align:start position:0% +so liz spelke has spun a whole + + + align:start position:0% +so liz spelke has spun a whole +fascinating big + + align:start position:0% +fascinating big + + + align:start position:0% +fascinating big +theoretical story + + align:start position:0% +theoretical story + + + align:start position:0% +theoretical story +about how what this really means well + + align:start position:0% +about how what this really means well + + + align:start position:0% +about how what this really means well +let me just say a little bit more about + + align:start position:0% +let me just say a little bit more about + + + align:start position:0% +let me just say a little bit more about +about this first before i do her whole + + align:start position:0% +about this first before i do her whole + + + align:start position:0% +about this first before i do her whole +big story okay yeah so the idea is so + + align:start position:0% +big story okay yeah so the idea is so + + + align:start position:0% +big story okay yeah so the idea is so +first of all + + align:start position:0% +first of all + + + align:start position:0% +first of all +why would it make sense for rodents at + + align:start position:0% +why would it make sense for rodents at + + + align:start position:0% +why would it make sense for rodents at +least let's just consider the rats to + + align:start position:0% +least let's just consider the rats to + + + align:start position:0% +least let's just consider the rats to +use only the shape of space to reorient + + align:start position:0% +use only the shape of space to reorient + + + align:start position:0% +use only the shape of space to reorient +themselves when they're disoriented at + + align:start position:0% +themselves when they're disoriented at + + + align:start position:0% +themselves when they're disoriented at +first glance that seems really crazy + + align:start position:0% +first glance that seems really crazy + + + align:start position:0% +first glance that seems really crazy +but if you think about rodents in + + align:start position:0% +but if you think about rodents in + + + align:start position:0% +but if you think about rodents in +natural environments + + align:start position:0% +natural environments + + + align:start position:0% +natural environments +the idea is that like actually in + + align:start position:0% +the idea is that like actually in + + + align:start position:0% +the idea is that like actually in +natural environments features change + + align:start position:0% +natural environments features change + + + align:start position:0% +natural environments features change +snow comes and goes plants come and go + + align:start position:0% +snow comes and goes plants come and go + + + align:start position:0% +snow comes and goes plants come and go +odors change + + align:start position:0% +odors change + + + align:start position:0% +odors change +all those kinds of + + align:start position:0% +all those kinds of + + + align:start position:0% +all those kinds of +features of the environment can change + + align:start position:0% +features of the environment can change + + + align:start position:0% +features of the environment can change +but the + + align:start position:0% +but the + + + align:start position:0% +but the +shape of the environment like that + + align:start position:0% +shape of the environment like that + + + align:start position:0% +shape of the environment like that +there's a slope like this and a barrier + + align:start position:0% +there's a slope like this and a barrier + + + align:start position:0% +there's a slope like this and a barrier +here and a cliff there those are more + + align:start position:0% +here and a cliff there those are more + + + align:start position:0% +here and a cliff there those are more +stable features of the environment so it + + align:start position:0% +stable features of the environment so it + + + align:start position:0% +stable features of the environment so it +actually makes evolutionary sense for + + align:start position:0% +actually makes evolutionary sense for + + + align:start position:0% +actually makes evolutionary sense for +disoriented rodents at least to use the + + align:start position:0% +disoriented rodents at least to use the + + + align:start position:0% +disoriented rodents at least to use the +shape of space more than the features + + align:start position:0% +shape of space more than the features + + + align:start position:0% +shape of space more than the features +the colors and textures and odors of a + + align:start position:0% +the colors and textures and odors of a + + + align:start position:0% +the colors and textures and odors of a +space + + align:start position:0% +space + + + align:start position:0% +space +as landmarks to reorient themselves does + + align:start position:0% +as landmarks to reorient themselves does + + + align:start position:0% +as landmarks to reorient themselves does +that make sense + + align:start position:0% +that make sense + + + align:start position:0% +that make sense +and so the idea is that rodents have + + align:start position:0% +and so the idea is that rodents have + + + align:start position:0% +and so the idea is that rodents have +through evolution kind of evolved this + + align:start position:0% +through evolution kind of evolved this + + + align:start position:0% +through evolution kind of evolved this +system for reorienting themselves when + + align:start position:0% +system for reorienting themselves when + + + align:start position:0% +system for reorienting themselves when +they lose their bearings that relies + + align:start position:0% +they lose their bearings that relies + + + align:start position:0% +they lose their bearings that relies +only on the shape of space + + align:start position:0% +only on the shape of space + + + align:start position:0% +only on the shape of space +so restrictively that even if another + + align:start position:0% +so restrictively that even if another + + + align:start position:0% +so restrictively that even if another +cue becomes relevant and important they + + align:start position:0% +cue becomes relevant and important they + + + align:start position:0% +cue becomes relevant and important they +don't use it + + align:start position:0% +don't use it + + + align:start position:0% +don't use it +okay + + align:start position:0% +okay + + + align:start position:0% +okay +the further idea is that we have some + + align:start position:0% +the further idea is that we have some + + + align:start position:0% +the further idea is that we have some +version of this system in our heads as + + align:start position:0% +version of this system in our heads as + + + align:start position:0% +version of this system in our heads as +well + + align:start position:0% +well + + + align:start position:0% +well +and as smart adult humans we learn all + + align:start position:0% +and as smart adult humans we learn all + + + align:start position:0% +and as smart adult humans we learn all +kinds of other strategies to get beyond + + align:start position:0% +kinds of other strategies to get beyond + + + align:start position:0% +kinds of other strategies to get beyond +this we're not trapped with only being + + align:start position:0% +this we're not trapped with only being + + + align:start position:0% +this we're not trapped with only being +able to use this one system to solve it + + align:start position:0% +able to use this one system to solve it + + + align:start position:0% +able to use this one system to solve it +we can use other systems + + align:start position:0% +we can use other systems + + + align:start position:0% +we can use other systems +possibly language to help us say things + + align:start position:0% +possibly language to help us say things + + + align:start position:0% +possibly language to help us say things +to ourselves like it's on the left side + + align:start position:0% +to ourselves like it's on the left side + + + align:start position:0% +to ourselves like it's on the left side +of the short wall + + align:start position:0% +of the short wall + + + align:start position:0% +of the short wall +right that's what spelkey thinks is + + align:start position:0% +right that's what spelkey thinks is + + + align:start position:0% +right that's what spelkey thinks is +there's some version in your head of + + align:start position:0% +there's some version in your head of + + + align:start position:0% +there's some version in your head of +it's on the left side of the short wall + + align:start position:0% +it's on the left side of the short wall + + + align:start position:0% +it's on the left side of the short wall +and that's why adults can do this + + align:start position:0% +and that's why adults can do this + + + align:start position:0% +and that's why adults can do this +when their language system isn't tied up + + align:start position:0% +when their language system isn't tied up + + + align:start position:0% +when their language system isn't tied up +i don't think that's exactly right but + + align:start position:0% +i don't think that's exactly right but + + + align:start position:0% +i don't think that's exactly right but +it's a beautiful story and there's some + + align:start position:0% +it's a beautiful story and there's some + + + align:start position:0% +it's a beautiful story and there's some +evidence for it okay + + align:start position:0% +evidence for it okay + + + align:start position:0% +evidence for it okay +anyway + + align:start position:0% +anyway + + + align:start position:0% +anyway +part of the reason i go through this + + align:start position:0% +part of the reason i go through this + + + align:start position:0% +part of the reason i go through this +whole thing well one i think these + + align:start position:0% +whole thing well one i think these + + + align:start position:0% +whole thing well one i think these +experiments are cool but it's also been + + align:start position:0% +experiments are cool but it's also been + + + align:start position:0% +experiments are cool but it's also been +the basis of a kind of core idea in + + align:start position:0% +the basis of a kind of core idea in + + + align:start position:0% +the basis of a kind of core idea in +cognitive science + + align:start position:0% +cognitive science + + + align:start position:0% +cognitive science +and that idea is called informational + + align:start position:0% +and that idea is called informational + + + align:start position:0% +and that idea is called informational +encapsulation + + align:start position:0% +encapsulation + + + align:start position:0% +encapsulation +so think about just lots of syllables + + align:start position:0% +so think about just lots of syllables + + + align:start position:0% +so think about just lots of syllables +for a pretty simple idea + + align:start position:0% +for a pretty simple idea + + + align:start position:0% +for a pretty simple idea +you have this system for reorientation + + align:start position:0% +you have this system for reorientation + + + align:start position:0% +you have this system for reorientation +and it is designed to use the shape of + + align:start position:0% +and it is designed to use the shape of + + + align:start position:0% +and it is designed to use the shape of +space around you as the cue that you use + + align:start position:0% +space around you as the cue that you use + + + align:start position:0% +space around you as the cue that you use +to reorient yourself when you're + + align:start position:0% +to reorient yourself when you're + + + align:start position:0% +to reorient yourself when you're +disoriented + + align:start position:0% +disoriented + + + align:start position:0% +disoriented +that system is kind of hardwired to do + + align:start position:0% +that system is kind of hardwired to do + + + align:start position:0% +that system is kind of hardwired to do +just that + + align:start position:0% +just that + + + align:start position:0% +just that +and if some other part of your brain has + + align:start position:0% +and if some other part of your brain has + + + align:start position:0% +and if some other part of your brain has +information that could solve the problem + + align:start position:0% +information that could solve the problem + + + align:start position:0% +information that could solve the problem +like the presence of a relevant feature + + align:start position:0% +like the presence of a relevant feature + + + align:start position:0% +like the presence of a relevant feature +that could you could use + + align:start position:0% +that could you could use + + + align:start position:0% +that could you could use +you don't have that's this your + + align:start position:0% +you don't have that's this your + + + align:start position:0% +you don't have that's this your +reorientation system doesn't have access + + align:start position:0% +reorientation system doesn't have access + + + align:start position:0% +reorientation system doesn't have access +to that information it's informationally + + align:start position:0% +to that information it's informationally + + + align:start position:0% +to that information it's informationally +encapsulated it only has access to the + + align:start position:0% +encapsulated it only has access to the + + + align:start position:0% +encapsulated it only has access to the +particular inputs that are kind of + + align:start position:0% +particular inputs that are kind of + + + align:start position:0% +particular inputs that are kind of +hardwired into it okay + + align:start position:0% +hardwired into it okay + + + align:start position:0% +hardwired into it okay +and so + + align:start position:0% +and so + + + align:start position:0% +and so +um 20 years ago a lot of people kind of + + align:start position:0% +um 20 years ago a lot of people kind of + + + align:start position:0% +um 20 years ago a lot of people kind of +went wild with us and said that all the + + align:start position:0% +went wild with us and said that all the + + + align:start position:0% +went wild with us and said that all the +you know brain regions that i've talked + + align:start position:0% +you know brain regions that i've talked + + + align:start position:0% +you know brain regions that i've talked +about and cognitive systems that we're + + align:start position:0% +about and cognitive systems that we're + + + align:start position:0% +about and cognitive systems that we're +considering this course are + + align:start position:0% +considering this course are + + + align:start position:0% +considering this course are +informationally encapsulated it's kind + + align:start position:0% +informationally encapsulated it's kind + + + align:start position:0% +informationally encapsulated it's kind +of an extreme idea that goes far beyond + + align:start position:0% +of an extreme idea that goes far beyond + + + align:start position:0% +of an extreme idea that goes far beyond +functional specificity to say like the + + align:start position:0% +functional specificity to say like the + + + align:start position:0% +functional specificity to say like the +inputs are extremely restricted to each + + align:start position:0% +inputs are extremely restricted to each + + + align:start position:0% +inputs are extremely restricted to each +region and that's probably not true + + align:start position:0% +region and that's probably not true + + + align:start position:0% +region and that's probably not true +but there's some + + align:start position:0% +but there's some + + + align:start position:0% +but there's some +limitations on the information that each + + align:start position:0% +limitations on the information that each + + + align:start position:0% +limitations on the information that each +of these processors we're considering in + + align:start position:0% +of these processors we're considering in + + + align:start position:0% +of these processors we're considering in +this course has access to and this is + + align:start position:0% +this course has access to and this is + + + align:start position:0% +this course has access to and this is +kind of the kind of classic evidence + + align:start position:0% +kind of the kind of classic evidence + + + align:start position:0% +kind of the kind of classic evidence +behavioral evidence that some of those + + align:start position:0% +behavioral evidence that some of those + + + align:start position:0% +behavioral evidence that some of those +systems have very restricted inputs does + + align:start position:0% +systems have very restricted inputs does + + + align:start position:0% +systems have very restricted inputs does +that make sense idea of informational + + align:start position:0% +that make sense idea of informational + + + align:start position:0% +that make sense idea of informational +encapsulation not is it you know + + align:start position:0% +encapsulation not is it you know + + + align:start position:0% +encapsulation not is it you know +absolute truth about the brain but as an + + align:start position:0% +absolute truth about the brain but as an + + + align:start position:0% +absolute truth about the brain but as an +idea that is + + align:start position:0% +idea that is + + + align:start position:0% +idea that is +interesting to consider + + align:start position:0% +interesting to consider + + + align:start position:0% +interesting to consider +individually for each of the systems we + + align:start position:0% +individually for each of the systems we + + + align:start position:0% +individually for each of the systems we +study + + align:start position:0% +study + + + align:start position:0% +study +there's been pushback about the + + align:start position:0% +there's been pushback about the + + + align:start position:0% +there's been pushback about the +extremeness of this claim that infants + + align:start position:0% +extremeness of this claim that infants + + + align:start position:0% +extremeness of this claim that infants +and rodents only use the shape of space + + align:start position:0% +and rodents only use the shape of space + + + align:start position:0% +and rodents only use the shape of space +there are circumstances where you can + + align:start position:0% +there are circumstances where you can + + + align:start position:0% +there are circumstances where you can +get them to use other information but + + align:start position:0% +get them to use other information but + + + align:start position:0% +get them to use other information but +it's definitely true that the shape of + + align:start position:0% +it's definitely true that the shape of + + + align:start position:0% +it's definitely true that the shape of +space is the dominant cue for + + align:start position:0% +space is the dominant cue for + + + align:start position:0% +space is the dominant cue for +reorienting + + align:start position:0% +reorienting + + + align:start position:0% +reorienting +in + + align:start position:0% +in + + + align:start position:0% +in +in rodents and infants + + align:start position:0% +in rodents and infants + + + align:start position:0% +in rodents and infants +all right + + align:start position:0% +all right + + + align:start position:0% +all right +so + + align:start position:0% +so + + + align:start position:0% +so +when you're lost as i've mentioned + + align:start position:0% +when you're lost as i've mentioned + + + align:start position:0% +when you're lost as i've mentioned +there's two questions you need to answer + + align:start position:0% +there's two questions you need to answer + + + align:start position:0% +there's two questions you need to answer +where are you and which way you're + + align:start position:0% +where are you and which way you're + + + align:start position:0% +where are you and which way you're +oriented right this last stuff we were + + align:start position:0% +oriented right this last stuff we were + + + align:start position:0% +oriented right this last stuff we were +talking about is about the which way + + align:start position:0% +talking about is about the which way + + + align:start position:0% +talking about is about the which way +you're oriented question + + align:start position:0% +you're oriented question + + + align:start position:0% +you're oriented question +okay and i just showed you some evidence + + align:start position:0% +okay and i just showed you some evidence + + + align:start position:0% +okay and i just showed you some evidence +for this general finding that the + + align:start position:0% +for this general finding that the + + + align:start position:0% +for this general finding that the +geometric cues the shape of space + + align:start position:0% +geometric cues the shape of space + + + align:start position:0% +geometric cues the shape of space +uh are the dominant cubes you use to + + align:start position:0% +uh are the dominant cubes you use to + + + align:start position:0% +uh are the dominant cubes you use to +reorient yourself to to get your heading + + align:start position:0% +reorient yourself to to get your heading + + + align:start position:0% +reorient yourself to to get your heading +back when you're disoriented okay + + align:start position:0% +back when you're disoriented okay + + + align:start position:0% +back when you're disoriented okay +um but + + align:start position:0% +um but + + + align:start position:0% +um but +do we really know that those cues are + + align:start position:0% +do we really know that those cues are + + + align:start position:0% +do we really know that those cues are +different for for place recognition and + + align:start position:0% +different for for place recognition and + + + align:start position:0% +different for for place recognition and +for heading direction right so i've sort + + align:start position:0% +for heading direction right so i've sort + + + align:start position:0% +for heading direction right so i've sort +of said here are two different parts of + + align:start position:0% +of said here are two different parts of + + + align:start position:0% +of said here are two different parts of +the problem but do they function + + align:start position:0% +the problem but do they function + + + align:start position:0% +the problem but do they function +differently + + align:start position:0% +differently + + + align:start position:0% +differently +do we really use different cues do we + + align:start position:0% +do we really use different cues do we + + + align:start position:0% +do we really use different cues do we +use the shape of space more for heading + + align:start position:0% +use the shape of space more for heading + + + align:start position:0% +use the shape of space more for heading +direction and maybe other cues for place + + align:start position:0% +direction and maybe other cues for place + + + align:start position:0% +direction and maybe other cues for place +recognition for knowing where we are + + align:start position:0% +recognition for knowing where we are + + + align:start position:0% +recognition for knowing where we are +okay so i'm going to show you a very + + align:start position:0% +okay so i'm going to show you a very + + + align:start position:0% +okay so i'm going to show you a very +elegant behavioral experiment in mice + + align:start position:0% +elegant behavioral experiment in mice + + + align:start position:0% +elegant behavioral experiment in mice +that does this all all at once in one + + align:start position:0% +that does this all all at once in one + + + align:start position:0% +that does this all all at once in one +experiment + + align:start position:0% +experiment + + + align:start position:0% +experiment +so this is josh julian a former lab tech + + align:start position:0% +so this is josh julian a former lab tech + + + align:start position:0% +so this is josh julian a former lab tech +in my lab i get no credit for this + + align:start position:0% +in my lab i get no credit for this + + + align:start position:0% +in my lab i get no credit for this +whatsoever i'm proud even though i + + align:start position:0% +whatsoever i'm proud even though i + + + align:start position:0% +whatsoever i'm proud even though i +shouldn't be proud he was just an + + align:start position:0% +shouldn't be proud he was just an + + + align:start position:0% +shouldn't be proud he was just an +endogenously smart guy who went on and + + align:start position:0% +endogenously smart guy who went on and + + + align:start position:0% +endogenously smart guy who went on and +did an awesome experiment after he left + + align:start position:0% +did an awesome experiment after he left + + + align:start position:0% +did an awesome experiment after he left +my lab and went off to grad school and + + align:start position:0% +my lab and went off to grad school and + + + align:start position:0% +my lab and went off to grad school and +here's his awesome experiment + + align:start position:0% +here's his awesome experiment + + + align:start position:0% +here's his awesome experiment +okay so he said let's get mice to do + + align:start position:0% +okay so he said let's get mice to do + + + align:start position:0% +okay so he said let's get mice to do +both of these tasks they have to know + + align:start position:0% +both of these tasks they have to know + + + align:start position:0% +both of these tasks they have to know +where they are and which way they're + + align:start position:0% +where they are and which way they're + + + align:start position:0% +where they are and which way they're +oriented + + align:start position:0% +oriented + + + align:start position:0% +oriented +okay we're gonna do the same + + align:start position:0% +okay we're gonna do the same + + + align:start position:0% +okay we're gonna do the same +disorientation thing take them out turn + + align:start position:0% +disorientation thing take them out turn + + + align:start position:0% +disorientation thing take them out turn +them around till they're disoriented but + + align:start position:0% +them around till they're disoriented but + + + align:start position:0% +them around till they're disoriented but +these mice have to learn two different + + align:start position:0% +these mice have to learn two different + + + align:start position:0% +these mice have to learn two different +environments okay one environment has + + align:start position:0% +environments okay one environment has + + + align:start position:0% +environments okay one environment has +the vertical stripes on the short wall + + align:start position:0% +the vertical stripes on the short wall + + + align:start position:0% +the vertical stripes on the short wall +on one of the short walls the other + + align:start position:0% +on one of the short walls the other + + + align:start position:0% +on one of the short walls the other +environment has horizontal stripes on + + align:start position:0% +environment has horizontal stripes on + + + align:start position:0% +environment has horizontal stripes on +the short wall + + align:start position:0% +the short wall + + + align:start position:0% +the short wall +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so you do the same experiment you bait + + align:start position:0% +so you do the same experiment you bait + + + align:start position:0% +so you do the same experiment you bait +one corner and you see where the rodent + + align:start position:0% +one corner and you see where the rodent + + + align:start position:0% +one corner and you see where the rodent +goes does he go to the two opposite + + align:start position:0% +goes does he go to the two opposite + + + align:start position:0% +goes does he go to the two opposite +corners + + align:start position:0% +corners + + + align:start position:0% +corners +exactly the same experiment but he has + + align:start position:0% +exactly the same experiment but he has + + + align:start position:0% +exactly the same experiment but he has +to remember which room is to solve the + + align:start position:0% +to remember which room is to solve the + + + align:start position:0% +to remember which room is to solve the +problem he has to know whether he's he + + align:start position:0% +problem he has to know whether he's he + + + align:start position:0% +problem he has to know whether he's he +has to discover rediscover the vertical + + align:start position:0% +has to discover rediscover the vertical + + + align:start position:0% +has to discover rediscover the vertical +stripes or the horizontal stripes and + + align:start position:0% +stripes or the horizontal stripes and + + + align:start position:0% +stripes or the horizontal stripes and +act accordingly because when he's in the + + align:start position:0% +act accordingly because when he's in the + + + align:start position:0% +act accordingly because when he's in the +vertical context the um the thing gets + + align:start position:0% +vertical context the um the thing gets + + + align:start position:0% +vertical context the um the thing gets +hit he does this over repeated trials + + align:start position:0% +hit he does this over repeated trials + + + align:start position:0% +hit he does this over repeated trials +the the the food gets hid + + align:start position:0% +the the the food gets hid + + + align:start position:0% +the the the food gets hid +um on the um + + align:start position:0% +um on the um + + + align:start position:0% +um on the um +uh + + align:start position:0% +uh + + + align:start position:0% +uh +hey let me get this right long wall on + + align:start position:0% +hey let me get this right long wall on + + + align:start position:0% +hey let me get this right long wall on +the left + + align:start position:0% +the left + + + align:start position:0% +the left +yeah right um + + align:start position:0% +yeah right um + + + align:start position:0% +yeah right um +yeah so + + align:start position:0% +yeah so + + + align:start position:0% +yeah so +when the long wall is on the left of the + + align:start position:0% +when the long wall is on the left of the + + + align:start position:0% +when the long wall is on the left of the +rodent okay that corner the long wall is + + align:start position:0% +rodent okay that corner the long wall is + + + align:start position:0% +rodent okay that corner the long wall is +on the left everybody oriented whereas + + align:start position:0% +on the left everybody oriented whereas + + + align:start position:0% +on the left everybody oriented whereas +when he's in the in the blue context the + + align:start position:0% +when he's in the in the blue context the + + + align:start position:0% +when he's in the in the blue context the +reward here + + align:start position:0% +reward here + + + align:start position:0% +reward here +the long wall is on the right + + align:start position:0% +the long wall is on the right + + + align:start position:0% +the long wall is on the right +okay so you have to learn those two + + align:start position:0% +okay so you have to learn those two + + + align:start position:0% +okay so you have to learn those two +different environments and that the + + align:start position:0% +different environments and that the + + + align:start position:0% +different environments and that the +the relevant shape cues are opposite in + + align:start position:0% +the relevant shape cues are opposite in + + + align:start position:0% +the relevant shape cues are opposite in +each okay everybody got that + + align:start position:0% +each okay everybody got that + + + align:start position:0% +each okay everybody got that +okay now + + align:start position:0% +okay now + + + align:start position:0% +okay now +what you find is that the rodent can + + align:start position:0% +what you find is that the rodent can + + + align:start position:0% +what you find is that the rodent can +learn that just fine okay so this shows + + align:start position:0% +learn that just fine okay so this shows + + + align:start position:0% +learn that just fine okay so this shows +that when you put the rodent in the + + align:start position:0% +that when you put the rodent in the + + + align:start position:0% +that when you put the rodent in the +vertical context in a room like this + + align:start position:0% +vertical context in a room like this + + + align:start position:0% +vertical context in a room like this +um they go more + + align:start position:0% +um they go more + + + align:start position:0% +um they go more +to these two corners than those two + + align:start position:0% +to these two corners than those two + + + align:start position:0% +to these two corners than those two +corners + + align:start position:0% +corners + + + align:start position:0% +corners +whereas when you put him in a um in a + + align:start position:0% +whereas when you put him in a um in a + + + align:start position:0% +whereas when you put him in a um in a +horizontal context with horizontal + + align:start position:0% +horizontal context with horizontal + + + align:start position:0% +horizontal context with horizontal +stripes he goes more to those two + + align:start position:0% +stripes he goes more to those two + + + align:start position:0% +stripes he goes more to those two +corners than those two corners + + align:start position:0% +corners than those two corners + + + align:start position:0% +corners than those two corners +that tells you the rodent has used the + + align:start position:0% +that tells you the rodent has used the + + + align:start position:0% +that tells you the rodent has used the +orientation of the stripes to figure out + + align:start position:0% +orientation of the stripes to figure out + + + align:start position:0% +orientation of the stripes to figure out +which room he's in and hence which two + + align:start position:0% +which room he's in and hence which two + + + align:start position:0% +which room he's in and hence which two +corners are the right ones + + align:start position:0% +corners are the right ones + + + align:start position:0% +corners are the right ones +everybody got that + + align:start position:0% +everybody got that + + + align:start position:0% +everybody got that +but here's the amazing thing even though + + align:start position:0% +but here's the amazing thing even though + + + align:start position:0% +but here's the amazing thing even though +in this experiment the very same animals + + align:start position:0% +in this experiment the very same animals + + + align:start position:0% +in this experiment the very same animals +in the very same trials are using those + + align:start position:0% +in the very same trials are using those + + + align:start position:0% +in the very same trials are using those +stripes + + align:start position:0% +stripes + + + align:start position:0% +stripes +to figure out which room they're in + + align:start position:0% +to figure out which room they're in + + + align:start position:0% +to figure out which room they're in +they don't use those stripes at all + + align:start position:0% +they don't use those stripes at all + + + align:start position:0% +they don't use those stripes at all +to break the symmetry and to go only to + + align:start position:0% +to break the symmetry and to go only to + + + align:start position:0% +to break the symmetry and to go only to +the great corner + + align:start position:0% +the great corner + + + align:start position:0% +the great corner +which they could do + + align:start position:0% +which they could do + + + align:start position:0% +which they could do +but don't + + align:start position:0% +but don't + + + align:start position:0% +but don't +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so + + align:start position:0% +so + + + align:start position:0% +so +once you've trained the rodents on these + + align:start position:0% +once you've trained the rodents on these + + + align:start position:0% +once you've trained the rodents on these +two things that the reward is here uh in + + align:start position:0% +two things that the reward is here uh in + + + align:start position:0% +two things that the reward is here uh in +um the ver the vertical context and + + align:start position:0% +um the ver the vertical context and + + + align:start position:0% +um the ver the vertical context and +they're in the horizontal context you + + align:start position:0% +they're in the horizontal context you + + + align:start position:0% +they're in the horizontal context you +disorient them you put them back in you + + align:start position:0% +disorient them you put them back in you + + + align:start position:0% +disorient them you put them back in you +find that when you have vertical stripes + + align:start position:0% +find that when you have vertical stripes + + + align:start position:0% +find that when you have vertical stripes +they go to these two corners i'm just + + align:start position:0% +they go to these two corners i'm just + + + align:start position:0% +they go to these two corners i'm just +repeating the data when there are + + align:start position:0% +repeating the data when there are + + + align:start position:0% +repeating the data when there are +horizontal stripes they go to those two + + align:start position:0% +horizontal stripes they go to those two + + + align:start position:0% +horizontal stripes they go to those two +corners okay they've learned that + + align:start position:0% +corners okay they've learned that + + + align:start position:0% +corners okay they've learned that +but why do they go to those two corners + + align:start position:0% +but why do they go to those two corners + + + align:start position:0% +but why do they go to those two corners +they learn the damn stripes they use + + align:start position:0% +they learn the damn stripes they use + + + align:start position:0% +they learn the damn stripes they use +them to know which room they're in but + + align:start position:0% +them to know which room they're in but + + + align:start position:0% +them to know which room they're in but +they don't use them to break the + + align:start position:0% +they don't use them to break the + + + align:start position:0% +they don't use them to break the +asymmetry and decide which is the + + align:start position:0% +asymmetry and decide which is the + + + align:start position:0% +asymmetry and decide which is the +correct corner + + align:start position:0% + + + + align:start position:0% + +okay so this is like a microcosm of + + align:start position:0% +okay so this is like a microcosm of + + + align:start position:0% +okay so this is like a microcosm of +everything i've been saying so far all + + align:start position:0% +everything i've been saying so far all + + + align:start position:0% +everything i've been saying so far all +in one experiment + + align:start position:0% +in one experiment + + + align:start position:0% +in one experiment +right the rodents are noticing those + + align:start position:0% +right the rodents are noticing those + + + align:start position:0% +right the rodents are noticing those +feature cues using them to figure out + + align:start position:0% +feature cues using them to figure out + + + align:start position:0% +feature cues using them to figure out +which room they're in where are they + + align:start position:0% +which room they're in where are they + + + align:start position:0% +which room they're in where are they +but failing to use those features the + + align:start position:0% +but failing to use those features the + + + align:start position:0% +but failing to use those features the +orientation of the stripes + + align:start position:0% +orientation of the stripes + + + align:start position:0% +orientation of the stripes +to figure out which of the two corners + + align:start position:0% +to figure out which of the two corners + + + align:start position:0% +to figure out which of the two corners +is the correct one + + align:start position:0% +is the correct one + + + align:start position:0% +is the correct one +they're not even encoding food is near + + align:start position:0% +they're not even encoding food is near + + + align:start position:0% +they're not even encoding food is near +stripes + + align:start position:0% +stripes + + + align:start position:0% +stripes +like duh that should have been easy + + align:start position:0% + + + + align:start position:0% + +right so this is a beautiful i mean this + + align:start position:0% +right so this is a beautiful i mean this + + + align:start position:0% +right so this is a beautiful i mean this +is even more evidence for informational + + align:start position:0% +is even more evidence for informational + + + align:start position:0% +is even more evidence for informational +encapsulation of this system because it + + align:start position:0% +encapsulation of this system because it + + + align:start position:0% +encapsulation of this system because it +shows us on the very same trial they + + align:start position:0% +shows us on the very same trial they + + + align:start position:0% +shows us on the very same trial they +used the stripe information to know + + align:start position:0% +used the stripe information to know + + + align:start position:0% +used the stripe information to know +which room they were they failed to use + + align:start position:0% +which room they were they failed to use + + + align:start position:0% +which room they were they failed to use +it to figure out their orientation in + + align:start position:0% +it to figure out their orientation in + + + align:start position:0% +it to figure out their orientation in +that room + + align:start position:0% + + + + align:start position:0% + +this sort of making sense i realized + + align:start position:0% +this sort of making sense i realized + + + align:start position:0% +this sort of making sense i realized +kind of subtle it's sort of simple and + + align:start position:0% +kind of subtle it's sort of simple and + + + align:start position:0% +kind of subtle it's sort of simple and +subtle at the same time + + align:start position:0% +subtle at the same time + + + align:start position:0% +subtle at the same time +um yeah so now the themselves that you + + align:start position:0% +um yeah so now the themselves that you + + + align:start position:0% +um yeah so now the themselves that you +showed us on the very first + + align:start position:0% +showed us on the very first + + + align:start position:0% +showed us on the very first +maps + + align:start position:0% +maps + + + align:start position:0% +maps +what are they doing here yeah exactly + + align:start position:0% +what are they doing here yeah exactly + + + align:start position:0% +what are they doing here yeah exactly +great question let's look at that that's + + align:start position:0% +great question let's look at that that's + + + align:start position:0% +great question let's look at that that's +what we're doing next it's a great + + align:start position:0% +what we're doing next it's a great + + + align:start position:0% +what we're doing next it's a great +question what are the damn place cells + + align:start position:0% +question what are the damn place cells + + + align:start position:0% +question what are the damn place cells +doing here + + align:start position:0% +doing here + + + align:start position:0% +doing here +great question + + align:start position:0% +great question + + + align:start position:0% +great question +okay let's say a little bit more and + + align:start position:0% +okay let's say a little bit more and + + + align:start position:0% +okay let's say a little bit more and +then we'll think about what the play + + align:start position:0% +then we'll think about what the play + + + align:start position:0% +then we'll think about what the play +cells are doing + + align:start position:0% +cells are doing + + + align:start position:0% +cells are doing +okay so let me just like restate cash + + align:start position:0% +okay so let me just like restate cash + + + align:start position:0% +okay so let me just like restate cash +out the findings here + + align:start position:0% +out the findings here + + + align:start position:0% +out the findings here +the mice are using the features to + + align:start position:0% +the mice are using the features to + + + align:start position:0% +the mice are using the features to +figure out which place they're in are + + align:start position:0% +figure out which place they're in are + + + align:start position:0% +figure out which place they're in are +they in this one or that one but they + + align:start position:0% +they in this one or that one but they + + + align:start position:0% +they in this one or that one but they +are failing + + align:start position:0% +are failing + + + align:start position:0% +are failing +to use those features to figure out + + align:start position:0% +to use those features to figure out + + + align:start position:0% +to use those features to figure out +which is the correct corner they're + + align:start position:0% +which is the correct corner they're + + + align:start position:0% +which is the correct corner they're +still 50 50 for the two corners even + + align:start position:0% +still 50 50 for the two corners even + + + align:start position:0% +still 50 50 for the two corners even +though + + align:start position:0% +though + + + align:start position:0% +though +logically they have that information and + + align:start position:0% +logically they have that information and + + + align:start position:0% +logically they have that information and +they could use it and they should use it + + align:start position:0% +they could use it and they should use it + + + align:start position:0% +they could use it and they should use it +they don't + + align:start position:0% +they don't + + + align:start position:0% +they don't +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so that means the mice are using + + align:start position:0% +so that means the mice are using + + + align:start position:0% +so that means the mice are using +features in this case orientation for + + align:start position:0% +features in this case orientation for + + + align:start position:0% +features in this case orientation for +place recognition + + align:start position:0% +place recognition + + + align:start position:0% +place recognition +but not for um regaining their + + align:start position:0% +but not for um regaining their + + + align:start position:0% +but not for um regaining their +orientation within that place + + align:start position:0% +orientation within that place + + + align:start position:0% +orientation within that place +i've just i'm just repeating what i said + + align:start position:0% +i've just i'm just repeating what i said + + + align:start position:0% +i've just i'm just repeating what i said +before is that making sense + + align:start position:0% +before is that making sense + + + align:start position:0% +before is that making sense +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so now + + align:start position:0% +so now + + + align:start position:0% +so now +david's question what are the place + + align:start position:0% +david's question what are the place + + + align:start position:0% +david's question what are the place +cells doing here great question let's + + align:start position:0% +cells doing here great question let's + + + align:start position:0% +cells doing here great question let's +look it's mice so we can do that + + align:start position:0% +look it's mice so we can do that + + + align:start position:0% +look it's mice so we can do that +or k nathat all can do that and josh + + align:start position:0% +or k nathat all can do that and josh + + + align:start position:0% +or k nathat all can do that and josh +julian my amazing former lab tech so + + align:start position:0% +julian my amazing former lab tech so + + + align:start position:0% +julian my amazing former lab tech so +again i get no credit whatsoever + + align:start position:0% +again i get no credit whatsoever + + + align:start position:0% +again i get no credit whatsoever +okay so what do they do + + align:start position:0% +okay so what do they do + + + align:start position:0% +okay so what do they do +they allow the mice to forage for crumbs + + align:start position:0% +they allow the mice to forage for crumbs + + + align:start position:0% +they allow the mice to forage for crumbs +in a box like this okay + + align:start position:0% + + + + align:start position:0% + +they disorient the mouse before each + + align:start position:0% +they disorient the mouse before each + + + align:start position:0% +they disorient the mouse before each +trial take him out turn him around so he + + align:start position:0% +trial take him out turn him around so he + + + align:start position:0% +trial take him out turn him around so he +doesn't know which way he's facing put + + align:start position:0% +doesn't know which way he's facing put + + + align:start position:0% +doesn't know which way he's facing put +him in the box + + align:start position:0% +him in the box + + + align:start position:0% +him in the box +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and they find that place cells have a + + align:start position:0% +and they find that place cells have a + + + align:start position:0% +and they find that place cells have a +particular location in that box not + + align:start position:0% +particular location in that box not + + + align:start position:0% +particular location in that box not +surprising that's what place cells do + + align:start position:0% +surprising that's what place cells do + + + align:start position:0% +surprising that's what place cells do +so here are two different trials two + + align:start position:0% +so here are two different trials two + + + align:start position:0% +so here are two different trials two +different cells that were mapped out in + + align:start position:0% +different cells that were mapped out in + + + align:start position:0% +different cells that were mapped out in +a rodent doing this this cell responds + + align:start position:0% +a rodent doing this this cell responds + + + align:start position:0% +a rodent doing this this cell responds +always in that corner + + align:start position:0% +always in that corner + + + align:start position:0% +always in that corner +another cell responds only in that + + align:start position:0% +another cell responds only in that + + + align:start position:0% +another cell responds only in that +corner okay these are just place cells + + align:start position:0% +corner okay these are just place cells + + + align:start position:0% +corner okay these are just place cells +like we described before doing what + + align:start position:0% +like we described before doing what + + + align:start position:0% +like we described before doing what +place cells do + + align:start position:0% +place cells do + + + align:start position:0% +place cells do +okay + + align:start position:0% + + + + align:start position:0% + +but now + + align:start position:0% +but now + + + align:start position:0% +but now +sometimes those place cells are off by + + align:start position:0% +sometimes those place cells are off by + + + align:start position:0% +sometimes those place cells are off by +180 degrees + + align:start position:0% +180 degrees + + + align:start position:0% +180 degrees +even though the stripes should resolve + + align:start position:0% +even though the stripes should resolve + + + align:start position:0% +even though the stripes should resolve +the ambiguity + + align:start position:0% +the ambiguity + + + align:start position:0% +the ambiguity +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so those same cells + + align:start position:0% +so those same cells + + + align:start position:0% +so those same cells +on other trials + + align:start position:0% +on other trials + + + align:start position:0% +on other trials +respond to the opposite corner + + align:start position:0% + + + + align:start position:0% + +so the place cells + + align:start position:0% +so the place cells + + + align:start position:0% +so the place cells +are doing just what the rodent is doing + + align:start position:0% +are doing just what the rodent is doing + + + align:start position:0% +are doing just what the rodent is doing +the place cells are confused am i facing + + align:start position:0% +the place cells are confused am i facing + + + align:start position:0% +the place cells are confused am i facing +you know am i am i phase am i oriented + + align:start position:0% +you know am i am i phase am i oriented + + + align:start position:0% +you know am i am i phase am i oriented +like this or am i oriented like that the + + align:start position:0% +like this or am i oriented like that the + + + align:start position:0% +like this or am i oriented like that the +place cells don't know and the rodent + + align:start position:0% +place cells don't know and the rodent + + + align:start position:0% +place cells don't know and the rodent +doesn't know + + align:start position:0% +doesn't know + + + align:start position:0% +doesn't know +and the coolest thing about this + + align:start position:0% +and the coolest thing about this + + + align:start position:0% +and the coolest thing about this +experiment is that these things are + + align:start position:0% +experiment is that these things are + + + align:start position:0% +experiment is that these things are +linked on the trials where the rodent + + align:start position:0% +linked on the trials where the rodent + + + align:start position:0% +linked on the trials where the rodent +goes to the wrong corner the place cells + + align:start position:0% +goes to the wrong corner the place cells + + + align:start position:0% +goes to the wrong corner the place cells +are also in the wrong corner + + align:start position:0% +are also in the wrong corner + + + align:start position:0% +are also in the wrong corner +okay they systematically determine which + + align:start position:0% +okay they systematically determine which + + + align:start position:0% +okay they systematically determine which +way the animal will go + + align:start position:0% +way the animal will go + + + align:start position:0% +way the animal will go +okay so + + align:start position:0% +okay so + + + align:start position:0% +okay so +um oh and also as i mentioned before + + align:start position:0% +um oh and also as i mentioned before + + + align:start position:0% +um oh and also as i mentioned before +like all those cells are in cahoots + + align:start position:0% +like all those cells are in cahoots + + + align:start position:0% +like all those cells are in cahoots +they're all in sync going the same way + + align:start position:0% +they're all in sync going the same way + + + align:start position:0% +they're all in sync going the same way +so when one of the cells + + align:start position:0% +so when one of the cells + + + align:start position:0% +so when one of the cells +rotates to the opposite corner all the + + align:start position:0% +rotates to the opposite corner all the + + + align:start position:0% +rotates to the opposite corner all the +other ones rotate to the opposite corner + + align:start position:0% +other ones rotate to the opposite corner + + + align:start position:0% +other ones rotate to the opposite corner +so it's as though somehow on trial to + + align:start position:0% +so it's as though somehow on trial to + + + align:start position:0% +so it's as though somehow on trial to +trial + + align:start position:0% +trial + + + align:start position:0% +trial +the rodent + + align:start position:0% +the rodent + + + align:start position:0% +the rodent +thinks he's oriented in one way he's + + align:start position:0% +thinks he's oriented in one way he's + + + align:start position:0% +thinks he's oriented in one way he's +actually 50 50 which way he's oriented + + align:start position:0% +actually 50 50 which way he's oriented + + + align:start position:0% +actually 50 50 which way he's oriented +he's not using the feature cues + + align:start position:0% +he's not using the feature cues + + + align:start position:0% +he's not using the feature cues +and his behavior according to where he + + align:start position:0% +and his behavior according to where he + + + align:start position:0% +and his behavior according to where he +looks for the food + + align:start position:0% +looks for the food + + + align:start position:0% +looks for the food +exactly follows that way he's oriented + + align:start position:0% +exactly follows that way he's oriented + + + align:start position:0% +exactly follows that way he's oriented +and so do all of his place cells + + align:start position:0% +and so do all of his place cells + + + align:start position:0% +and so do all of his place cells +okay that's that whole system goes + + align:start position:0% +okay that's that whole system goes + + + align:start position:0% +okay that's that whole system goes +together + + align:start position:0% +together + + + align:start position:0% +together +that tells you that those place cells + + align:start position:0% +that tells you that those place cells + + + align:start position:0% +that tells you that those place cells +are relevant behaviorally they are the + + align:start position:0% +are relevant behaviorally they are the + + + align:start position:0% +are relevant behaviorally they are the +they are the system that either directly + + align:start position:0% +they are the system that either directly + + + align:start position:0% +they are the system that either directly +determines or is tightly linked to the + + align:start position:0% +determines or is tightly linked to the + + + align:start position:0% +determines or is tightly linked to the +system that determines + + align:start position:0% +system that determines + + + align:start position:0% +system that determines +which way the animal thinks he's facing + + align:start position:0% +which way the animal thinks he's facing + + + align:start position:0% +which way the animal thinks he's facing +okay i realize this is a little bit + + align:start position:0% +okay i realize this is a little bit + + + align:start position:0% +okay i realize this is a little bit +complicated + + align:start position:0% +complicated + + + align:start position:0% +complicated +um + + align:start position:0% +um + + + align:start position:0% +um +does it make sense to you that + + align:start position:0% +does it make sense to you that + + + align:start position:0% +does it make sense to you that +you know as we've been talking about + + align:start position:0% +you know as we've been talking about + + + align:start position:0% +you know as we've been talking about +with reorientation + + align:start position:0% +with reorientation + + + align:start position:0% +with reorientation +even though the animal should know from + + align:start position:0% +even though the animal should know from + + + align:start position:0% +even though the animal should know from +this stripe + + align:start position:0% +this stripe + + + align:start position:0% +this stripe +the difference between that corner and + + align:start position:0% +the difference between that corner and + + + align:start position:0% +the difference between that corner and +this corner he doesn't know behaviorally + + align:start position:0% +this corner he doesn't know behaviorally + + + align:start position:0% +this corner he doesn't know behaviorally +he's looking for food right there and + + align:start position:0% +he's looking for food right there and + + + align:start position:0% +he's looking for food right there and +yet he goes 50 50. weird and stupid + + align:start position:0% +yet he goes 50 50. weird and stupid + + + align:start position:0% +yet he goes 50 50. weird and stupid +right + + align:start position:0% +right + + + align:start position:0% +right +place cells do the same thing + + align:start position:0% +place cells do the same thing + + + align:start position:0% +place cells do the same thing +okay and further the place cells and the + + align:start position:0% +okay and further the place cells and the + + + align:start position:0% +okay and further the place cells and the +behavior go together + + align:start position:0% +behavior go together + + + align:start position:0% +behavior go together +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +so if you're reading information off of + + align:start position:0% +so if you're reading information off of + + + align:start position:0% +so if you're reading information off of +play sales can you stop it can you + + align:start position:0% +play sales can you stop it can you + + + align:start position:0% +play sales can you stop it can you +provide ah + + align:start position:0% +provide ah + + + align:start position:0% +provide ah +wouldn't that be nice + + align:start position:0% +wouldn't that be nice + + + align:start position:0% +wouldn't that be nice +turns out you can't for the reason + + align:start position:0% +turns out you can't for the reason + + + align:start position:0% +turns out you can't for the reason +someone over here asked a long time ago + + align:start position:0% +someone over here asked a long time ago + + + align:start position:0% +someone over here asked a long time ago +you i think + + align:start position:0% +you i think + + + align:start position:0% +you i think +um + + align:start position:0% +um + + + align:start position:0% +um +and that's because they're all + + align:start position:0% +and that's because they're all + + + align:start position:0% +and that's because they're all +interleaved together + + align:start position:0% +interleaved together + + + align:start position:0% +interleaved together +and if you zap just one you're not going + + align:start position:0% +and if you zap just one you're not going + + + align:start position:0% +and if you zap just one you're not going +to one cell you're not going to have an + + align:start position:0% +to one cell you're not going to have an + + + align:start position:0% +to one cell you're not going to have an +effect and if you zap a whole region you + + align:start position:0% +effect and if you zap a whole region you + + + align:start position:0% +effect and if you zap a whole region you +get all of them and you get muck + + align:start position:0% +get all of them and you get muck + + + align:start position:0% +get all of them and you get muck +so you can't do that manipulation + + align:start position:0% +so you can't do that manipulation + + + align:start position:0% +so you can't do that manipulation +unfortunately you need some kind of + + align:start position:0% +unfortunately you need some kind of + + + align:start position:0% +unfortunately you need some kind of +topography to do the manipulation + + align:start position:0% +topography to do the manipulation + + + align:start position:0% +topography to do the manipulation +okay + + align:start position:0% +okay + + + align:start position:0% +okay +okay so i just said how all this + + align:start position:0% +okay so i just said how all this + + + align:start position:0% +okay so i just said how all this +i got ahead of myself how it relates to + + align:start position:0% +i got ahead of myself how it relates to + + + align:start position:0% +i got ahead of myself how it relates to +behavior uh but just to go through that + + align:start position:0% +behavior uh but just to go through that + + + align:start position:0% +behavior uh but just to go through that +quickly so what we've done here is + + align:start position:0% +quickly so what we've done here is + + + align:start position:0% +quickly so what we've done here is +they've trained the mouse on this + + align:start position:0% +they've trained the mouse on this + + + align:start position:0% +they've trained the mouse on this +classic reorientation task they + + align:start position:0% +classic reorientation task they + + + align:start position:0% +classic reorientation task they +disorient the mouse before each trial + + align:start position:0% +disorient the mouse before each trial + + + align:start position:0% +disorient the mouse before each trial +while recording from hippocampal place + + align:start position:0% +while recording from hippocampal place + + + align:start position:0% +while recording from hippocampal place +cells + + align:start position:0% +cells + + + align:start position:0% +cells +as before given cell flips 180 degrees + + align:start position:0% +as before given cell flips 180 degrees + + + align:start position:0% +as before given cell flips 180 degrees +from trial to trial + + align:start position:0% +from trial to trial + + + align:start position:0% +from trial to trial +despite the fact that the stripes should + + align:start position:0% +despite the fact that the stripes should + + + align:start position:0% +despite the fact that the stripes should +disambiguate it and tell them which way + + align:start position:0% +disambiguate it and tell them which way + + + align:start position:0% +disambiguate it and tell them which way +is oriented + + align:start position:0% +is oriented + + + align:start position:0% +is oriented +and by the way the head direction cells + + align:start position:0% +and by the way the head direction cells + + + align:start position:0% +and by the way the head direction cells +and the grid cells also flip in the same + + align:start position:0% +and the grid cells also flip in the same + + + align:start position:0% +and the grid cells also flip in the same +way in cahoots with the head with the + + align:start position:0% +way in cahoots with the head with the + + + align:start position:0% +way in cahoots with the head with the +place cells + + align:start position:0% +place cells + + + align:start position:0% +place cells +um + + align:start position:0% +um + + + align:start position:0% +um +but you can tell which corner the animal + + align:start position:0% +but you can tell which corner the animal + + + align:start position:0% +but you can tell which corner the animal +will go to by looking at what the place + + align:start position:0% +will go to by looking at what the place + + + align:start position:0% +will go to by looking at what the place +cells respond right + + align:start position:0% +cells respond right + + + align:start position:0% +cells respond right +and so when the place sells + + align:start position:0% +and so when the place sells + + + align:start position:0% +and so when the place sells +when this place cell + + align:start position:0% +when this place cell + + + align:start position:0% +when this place cell +represents that location the animal + + align:start position:0% +represents that location the animal + + + align:start position:0% +represents that location the animal +searches first there and when it flips + + align:start position:0% +searches first there and when it flips + + + align:start position:0% +searches first there and when it flips +around they search in the opposite + + align:start position:0% +around they search in the opposite + + + align:start position:0% +around they search in the opposite +corner + + align:start position:0% +corner + + + align:start position:0% +corner +okay so all of that just shows this + + align:start position:0% +okay so all of that just shows this + + + align:start position:0% +okay so all of that just shows this +really strong link between the play + + align:start position:0% +really strong link between the play + + + align:start position:0% +really strong link between the play +cells and behavior + + align:start position:0% +cells and behavior + + + align:start position:0% +cells and behavior +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so to recap we've talked about four + + align:start position:0% +so to recap we've talked about four + + + align:start position:0% +so to recap we've talked about four +different kinds of cells involved in + + align:start position:0% +different kinds of cells involved in + + + align:start position:0% +different kinds of cells involved in +representing space and navigating around + + align:start position:0% +representing space and navigating around + + + align:start position:0% +representing space and navigating around +in it + + align:start position:0% +in it + + + align:start position:0% +in it +place cells that are like the you are + + align:start position:0% +place cells that are like the you are + + + align:start position:0% +place cells that are like the you are +here they respond when you're in a + + align:start position:0% +here they respond when you're in a + + + align:start position:0% +here they respond when you're in a +particular location direction cells that + + align:start position:0% +particular location direction cells that + + + align:start position:0% +particular location direction cells that +respond when you're heading in one + + align:start position:0% +respond when you're heading in one + + + align:start position:0% +respond when you're heading in one +direction not in another direction + + align:start position:0% +direction not in another direction + + + align:start position:0% +direction not in another direction +uh border cells that represent that that + + align:start position:0% +uh border cells that represent that that + + + align:start position:0% +uh border cells that represent that that +fire when you're near a particular + + align:start position:0% +fire when you're near a particular + + + align:start position:0% +fire when you're near a particular +border in the environment i have border + + align:start position:0% +border in the environment i have border + + + align:start position:0% +border in the environment i have border +cells going right now throughout this + + align:start position:0% +cells going right now throughout this + + + align:start position:0% +cells going right now throughout this +whole lecture i've got a batch of border + + align:start position:0% +whole lecture i've got a batch of border + + + align:start position:0% +whole lecture i've got a batch of border +cells right that are going + + align:start position:0% +cells right that are going + + + align:start position:0% +cells right that are going +grid cells that do this amazing thing of + + align:start position:0% +grid cells that do this amazing thing of + + + align:start position:0% +grid cells that do this amazing thing of +firing when the animal is in multiple + + align:start position:0% +firing when the animal is in multiple + + + align:start position:0% +firing when the animal is in multiple +different locations and those locations + + align:start position:0% +different locations and those locations + + + align:start position:0% +different locations and those locations +that make it fire are arranged in a + + align:start position:0% +that make it fire are arranged in a + + + align:start position:0% +that make it fire are arranged in a +hexagonal grid + + align:start position:0% +hexagonal grid + + + align:start position:0% +hexagonal grid +think of it as a kind of ruler telling + + align:start position:0% +think of it as a kind of ruler telling + + + align:start position:0% +think of it as a kind of ruler telling +the rodent how far he's gone in his + + align:start position:0% +the rodent how far he's gone in his + + + align:start position:0% +the rodent how far he's gone in his +space and those grid cells are like the + + align:start position:0% +space and those grid cells are like the + + + align:start position:0% +space and those grid cells are like the +rulers + + align:start position:0% + + + + align:start position:0% + +yeah right + + align:start position:0% +yeah right + + + align:start position:0% +yeah right +those are those are the four kind we've + + align:start position:0% +those are those are the four kind we've + + + align:start position:0% +those are those are the four kind we've +talked about okay + + align:start position:0% +talked about okay + + + align:start position:0% +talked about okay +so now + + align:start position:0% +so now + + + align:start position:0% +so now +here's the cool thing all this stuff + + align:start position:0% +here's the cool thing all this stuff + + + align:start position:0% +here's the cool thing all this stuff +navigation is awesome + + align:start position:0% +navigation is awesome + + + align:start position:0% +navigation is awesome +right we need it it's important all + + align:start position:0% +right we need it it's important all + + + align:start position:0% +right we need it it's important all +night you know all uh mobile animals + + align:start position:0% +night you know all uh mobile animals + + + align:start position:0% +night you know all uh mobile animals +need it for the reasons we've been + + align:start position:0% +need it for the reasons we've been + + + align:start position:0% +need it for the reasons we've been +talking about + + align:start position:0% +talking about + + + align:start position:0% +talking about +but you you can use this whole system + + align:start position:0% +but you you can use this whole system + + + align:start position:0% +but you you can use this whole system +for so much more than just navigation + + align:start position:0% +for so much more than just navigation + + + align:start position:0% +for so much more than just navigation +once you have this fancy system in your + + align:start position:0% +once you have this fancy system in your + + + align:start position:0% +once you have this fancy system in your +head to keep track of your location to + + align:start position:0% +head to keep track of your location to + + + align:start position:0% +head to keep track of your location to +keep track of your direction to keep + + align:start position:0% +keep track of your direction to keep + + + align:start position:0% +keep track of your direction to keep +track of where things are how you're + + align:start position:0% +track of where things are how you're + + + align:start position:0% +track of where things are how you're +moving through that space you can use + + align:start position:0% +moving through that space you can use + + + align:start position:0% +moving through that space you can use +that whole magnificent system in other + + align:start position:0% +that whole magnificent system in other + + + align:start position:0% +that whole magnificent system in other +ways and in the last three or four years + + align:start position:0% +ways and in the last three or four years + + + align:start position:0% +ways and in the last three or four years +there's just a huge number of studies + + align:start position:0% +there's just a huge number of studies + + + align:start position:0% +there's just a huge number of studies +that are really starting to take this + + align:start position:0% +that are really starting to take this + + + align:start position:0% +that are really starting to take this +very seriously particularly the grid + + align:start position:0% +very seriously particularly the grid + + + align:start position:0% +very seriously particularly the grid +cells and thinking about how the grid + + align:start position:0% +cells and thinking about how the grid + + + align:start position:0% +cells and thinking about how the grid +cells + + align:start position:0% +cells + + + align:start position:0% +cells +i mean probably the whole system but + + align:start position:0% +i mean probably the whole system but + + + align:start position:0% +i mean probably the whole system but +people have been focusing on the grid + + align:start position:0% +people have been focusing on the grid + + + align:start position:0% +people have been focusing on the grid +cells + + align:start position:0% +cells + + + align:start position:0% +cells +and how they're used in multiple + + align:start position:0% +and how they're used in multiple + + + align:start position:0% +and how they're used in multiple +different situations + + align:start position:0% +different situations + + + align:start position:0% +different situations +so here's one + + align:start position:0% +so here's one + + + align:start position:0% +so here's one +okay this is a cool study where what + + align:start position:0% +okay this is a cool study where what + + + align:start position:0% +okay this is a cool study where what +these guys did was they stuck a little + + align:start position:0% +these guys did was they stuck a little + + + align:start position:0% +these guys did was they stuck a little +device hanging around people's necks the + + align:start position:0% +device hanging around people's necks the + + + align:start position:0% +device hanging around people's necks the +subject's necks have little camera + + align:start position:0% +subject's necks have little camera + + + align:start position:0% +subject's necks have little camera +aiming forward it takes pictures at + + align:start position:0% +aiming forward it takes pictures at + + + align:start position:0% +aiming forward it takes pictures at +random intervals and records the + + align:start position:0% +random intervals and records the + + + align:start position:0% +random intervals and records the +person's gps location okay + + align:start position:0% +person's gps location okay + + + align:start position:0% +person's gps location okay +so you send them off for a few months + + align:start position:0% +so you send them off for a few months + + + align:start position:0% +so you send them off for a few months +with this little device and you do + + align:start position:0% +with this little device and you do + + + align:start position:0% +with this little device and you do +something to protect people's privacy i + + align:start position:0% +something to protect people's privacy i + + + align:start position:0% +something to protect people's privacy i +don't know exactly how they maneuver + + align:start position:0% +don't know exactly how they maneuver + + + align:start position:0% +don't know exactly how they maneuver +that but i'm sure they found a way + + align:start position:0% +that but i'm sure they found a way + + + align:start position:0% +that but i'm sure they found a way +uh and so then they get this set of + + align:start position:0% +uh and so then they get this set of + + + align:start position:0% +uh and so then they get this set of +photographs taken from this person's + + align:start position:0% +photographs taken from this person's + + + align:start position:0% +photographs taken from this person's +kind of front view of wherever they were + + align:start position:0% +kind of front view of wherever they were + + + align:start position:0% +kind of front view of wherever they were +over several months as they went + + align:start position:0% +over several months as they went + + + align:start position:0% +over several months as they went +wherever they went in their lives okay + + align:start position:0% +wherever they went in their lives okay + + + align:start position:0% +wherever they went in their lives okay +with a little gps tag for each + + align:start position:0% +with a little gps tag for each + + + align:start position:0% +with a little gps tag for each +photograph okay + + align:start position:0% +photograph okay + + + align:start position:0% +photograph okay +so then what they do is they bring the + + align:start position:0% +so then what they do is they bring the + + + align:start position:0% +so then what they do is they bring the +subjects in and pop them in the scanner + + align:start position:0% +subjects in and pop them in the scanner + + + align:start position:0% +subjects in and pop them in the scanner +and show them some of those pictures + + align:start position:0% +and show them some of those pictures + + + align:start position:0% +and show them some of those pictures +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and they asked people to relive the + + align:start position:0% +and they asked people to relive the + + + align:start position:0% +and they asked people to relive the +experience that they had when they were + + align:start position:0% +experience that they had when they were + + + align:start position:0% +experience that they had when they were +looking at that thing + + align:start position:0% +looking at that thing + + + align:start position:0% +looking at that thing +right if you put this on me it'd be my + + align:start position:0% +right if you put this on me it'd be my + + + align:start position:0% +right if you put this on me it'd be my +monitor like all the time and i wouldn't + + align:start position:0% +monitor like all the time and i wouldn't + + + align:start position:0% +monitor like all the time and i wouldn't +know which + + align:start position:0% +know which + + + align:start position:0% +know which +experience to relive but i guess these + + align:start position:0% +experience to relive but i guess these + + + align:start position:0% +experience to relive but i guess these +people had you know richer lives let's + + align:start position:0% +people had you know richer lives let's + + + align:start position:0% +people had you know richer lives let's +hope + + align:start position:0% +hope + + + align:start position:0% +hope +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so now what they do is they use multiple + + align:start position:0% +so now what they do is they use multiple + + + align:start position:0% +so now what they do is they use multiple +voxel pattern analysis + + align:start position:0% +voxel pattern analysis + + + align:start position:0% +voxel pattern analysis +in the hippocampus + + align:start position:0% +in the hippocampus + + + align:start position:0% +in the hippocampus +while people are reliving those + + align:start position:0% +while people are reliving those + + + align:start position:0% +while people are reliving those +experiences in the scanner by looking at + + align:start position:0% +experiences in the scanner by looking at + + + align:start position:0% +experiences in the scanner by looking at +those images taken from their + + align:start position:0% +those images taken from their + + + align:start position:0% +those images taken from their +front-facing cameras + + align:start position:0% +front-facing cameras + + + align:start position:0% +front-facing cameras +okay + + align:start position:0% +okay + + + align:start position:0% +okay +um and then they asked is the pattern of + + align:start position:0% +um and then they asked is the pattern of + + + align:start position:0% +um and then they asked is the pattern of +response in the hippocampus like some + + align:start position:0% +response in the hippocampus like some + + + align:start position:0% +response in the hippocampus like some +bunch of voxels here's some pattern + + align:start position:0% +bunch of voxels here's some pattern + + + align:start position:0% +bunch of voxels here's some pattern +is it more similar for events the + + align:start position:0% +is it more similar for events the + + + align:start position:0% +is it more similar for events the +subject remembers that are near that + + align:start position:0% +subject remembers that are near that + + + align:start position:0% +subject remembers that are near that +were nearby in space okay + + align:start position:0% +were nearby in space okay + + + align:start position:0% +were nearby in space okay +so you do this for me it's like yes i + + align:start position:0% +so you do this for me it's like yes i + + + align:start position:0% +so you do this for me it's like yes i +occasionally go to the state of + + align:start position:0% +occasionally go to the state of + + + align:start position:0% +occasionally go to the state of +cafeteria and i you know occasionally go + + align:start position:0% +cafeteria and i you know occasionally go + + + align:start position:0% +cafeteria and i you know occasionally go +to the + + align:start position:0% +to the + + + align:start position:0% +to the +koch center cafeteria + + align:start position:0% +koch center cafeteria + + + align:start position:0% +koch center cafeteria +and i spend a lot of time at home and + + align:start position:0% +and i spend a lot of time at home and + + + align:start position:0% +and i spend a lot of time at home and +those two things are closer to each + + align:start position:0% +those two things are closer to each + + + align:start position:0% +those two things are closer to each +other than my home thing are the + + align:start position:0% +other than my home thing are the + + + align:start position:0% +other than my home thing are the +patterns more similar for nearby + + align:start position:0% +patterns more similar for nearby + + + align:start position:0% +patterns more similar for nearby +locations than for more distant + + align:start position:0% +locations than for more distant + + + align:start position:0% +locations than for more distant +locations okay + + align:start position:0% +locations okay + + + align:start position:0% +locations okay +and they were + + align:start position:0% +and they were + + + align:start position:0% +and they were +so this is the distance on a log scale + + align:start position:0% +so this is the distance on a log scale + + + align:start position:0% +so this is the distance on a log scale +between two patterns + + align:start position:0% +between two patterns + + + align:start position:0% +between two patterns +that result from the subject looking at + + align:start position:0% +that result from the subject looking at + + + align:start position:0% +that result from the subject looking at +two different images and this is the + + align:start position:0% +two different images and this is the + + + align:start position:0% +two different images and this is the +similarity + + align:start position:0% +similarity + + + align:start position:0% +similarity +of the pattern in the hippocampus + + align:start position:0% +of the pattern in the hippocampus + + + align:start position:0% +of the pattern in the hippocampus +now some of you might be wondering in + + align:start position:0% +now some of you might be wondering in + + + align:start position:0% +now some of you might be wondering in +fact i wonder this too i think this is a + + align:start position:0% +fact i wonder this too i think this is a + + + align:start position:0% +fact i wonder this too i think this is a +cool study so i'm presenting it but it + + align:start position:0% +cool study so i'm presenting it but it + + + align:start position:0% +cool study so i'm presenting it but it +sort of doesn't make sense to me because + + align:start position:0% +sort of doesn't make sense to me because + + + align:start position:0% +sort of doesn't make sense to me because +everything we know about the hippocampus + + align:start position:0% +everything we know about the hippocampus + + + align:start position:0% +everything we know about the hippocampus +is those place cells are pretty + + align:start position:0% +is those place cells are pretty + + + align:start position:0% +is those place cells are pretty +interleaved so how you manage to get a + + align:start position:0% +interleaved so how you manage to get a + + + align:start position:0% +interleaved so how you manage to get a +pattern + + align:start position:0% +pattern + + + align:start position:0% +pattern +response + + align:start position:0% +response + + + align:start position:0% +response +reading out a systematic location out of + + align:start position:0% +reading out a systematic location out of + + + align:start position:0% +reading out a systematic location out of +the hippocampus is a mystery to me so + + align:start position:0% +the hippocampus is a mystery to me so + + + align:start position:0% +the hippocampus is a mystery to me so +they can't be like fully there must be + + align:start position:0% +they can't be like fully there must be + + + align:start position:0% +they can't be like fully there must be +some kind of structure in there to the + + align:start position:0% +some kind of structure in there to the + + + align:start position:0% +some kind of structure in there to the +layout of those cells + + align:start position:0% +layout of those cells + + + align:start position:0% +layout of those cells +um + + align:start position:0% +um + + + align:start position:0% +um +to enable them to get this information + + align:start position:0% +to enable them to get this information + + + align:start position:0% +to enable them to get this information +okay so everybody get how + + align:start position:0% +okay so everybody get how + + + align:start position:0% +okay so everybody get how +it's telling you that hippocampus is is + + align:start position:0% +it's telling you that hippocampus is is + + + align:start position:0% +it's telling you that hippocampus is is +remembering and reliving + + align:start position:0% +remembering and reliving + + + align:start position:0% +remembering and reliving +some representation of the locations of + + align:start position:0% +some representation of the locations of + + + align:start position:0% +some representation of the locations of +those + + align:start position:0% +those + + + align:start position:0% +those +of where you had those experiences + + align:start position:0% +of where you had those experiences + + + align:start position:0% +of where you had those experiences +everybody get how this shows us + + align:start position:0% +everybody get how this shows us + + + align:start position:0% +everybody get how this shows us +but then they asked another interesting + + align:start position:0% +but then they asked another interesting + + + align:start position:0% +but then they asked another interesting +question and they said oh + + align:start position:0% +question and they said oh + + + align:start position:0% +question and they said oh +does it also represent time so we've + + align:start position:0% +does it also represent time so we've + + + align:start position:0% +does it also represent time so we've +been talking about space for the last + + align:start position:0% +been talking about space for the last + + + align:start position:0% +been talking about space for the last +two lectures but now we're like going + + align:start position:0% +two lectures but now we're like going + + + align:start position:0% +two lectures but now we're like going +straight off the deep end and our first + + align:start position:0% +straight off the deep end and our first + + + align:start position:0% +straight off the deep end and our first +step not even near the deep end yet is + + align:start position:0% +step not even near the deep end yet is + + + align:start position:0% +step not even near the deep end yet is +does it do not just space but time + + align:start position:0% +does it do not just space but time + + + align:start position:0% +does it do not just space but time +so they can take all those photographs + + align:start position:0% +so they can take all those photographs + + + align:start position:0% +so they can take all those photographs +and say okay how far apart in time were + + align:start position:0% +and say okay how far apart in time were + + + align:start position:0% +and say okay how far apart in time were +these two photographs taken + + align:start position:0% +these two photographs taken + + + align:start position:0% +these two photographs taken +and they can do the same graph + + align:start position:0% +and they can do the same graph + + + align:start position:0% +and they can do the same graph +and yes they get a relationship with + + align:start position:0% +and yes they get a relationship with + + + align:start position:0% +and yes they get a relationship with +time as well the farther apart in time + + align:start position:0% +time as well the farther apart in time + + + align:start position:0% +time as well the farther apart in time +people saw those two patterns the more + + align:start position:0% +people saw those two patterns the more + + + align:start position:0% +people saw those two patterns the more +different the patterns in the + + align:start position:0% +different the patterns in the + + + align:start position:0% +different the patterns in the +hippocampus + + align:start position:0% +hippocampus + + + align:start position:0% +hippocampus +isn't that cool + + align:start position:0% +isn't that cool + + + align:start position:0% +isn't that cool +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so that's one example showing that the + + align:start position:0% +so that's one example showing that the + + + align:start position:0% +so that's one example showing that the +hippocampus holds some kind of + + align:start position:0% +hippocampus holds some kind of + + + align:start position:0% +hippocampus holds some kind of +large scale of representation of not + + align:start position:0% +large scale of representation of not + + + align:start position:0% +large scale of representation of not +just space but also time + + align:start position:0% +just space but also time + + + align:start position:0% +just space but also time +and so there's a lot of work on how this + + align:start position:0% +and so there's a lot of work on how this + + + align:start position:0% +and so there's a lot of work on how this +gives structures to our memories for + + align:start position:0% +gives structures to our memories for + + + align:start position:0% +gives structures to our memories for +distances over the range of + + align:start position:0% +distances over the range of + + + align:start position:0% +distances over the range of +100 meters and times between you know 15 + + align:start position:0% +100 meters and times between you know 15 + + + align:start position:0% +100 meters and times between you know 15 +hours + + align:start position:0% +hours + + + align:start position:0% +hours +and a month i'm going to run out of time + + align:start position:0% +and a month i'm going to run out of time + + + align:start position:0% +and a month i'm going to run out of time +so unless it's a clarification question + + align:start position:0% +so unless it's a clarification question + + + align:start position:0% +so unless it's a clarification question +i'm going to keep going + + align:start position:0% +i'm going to keep going + + + align:start position:0% +i'm going to keep going +yeah okay + + align:start position:0% +yeah okay + + + align:start position:0% +yeah okay +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +yes if you just did it like that so you + + align:start position:0% +yes if you just did it like that so you + + + align:start position:0% +yes if you just did it like that so you +have to do something to pick out + + align:start position:0% +have to do something to pick out + + + align:start position:0% +have to do something to pick out +um time things that aren't confounded + + align:start position:0% +um time things that aren't confounded + + + align:start position:0% +um time things that aren't confounded +with space you could you have this big + + align:start position:0% +with space you could you have this big + + + align:start position:0% +with space you could you have this big +sample of pictures and you take a subset + + align:start position:0% +sample of pictures and you take a subset + + + align:start position:0% +sample of pictures and you take a subset +where you balance for it absolutely they + + align:start position:0% +where you balance for it absolutely they + + + align:start position:0% +where you balance for it absolutely they +would have to do that + + align:start position:0% +would have to do that + + + align:start position:0% +would have to do that +i can't actually remember but they must + + align:start position:0% +i can't actually remember but they must + + + align:start position:0% +i can't actually remember but they must +have done that you'd + + align:start position:0% +have done that you'd + + + align:start position:0% +have done that you'd +imperfect as peer review is you'd never + + align:start position:0% +imperfect as peer review is you'd never + + + align:start position:0% +imperfect as peer review is you'd never +get through peer review if you didn't + + align:start position:0% +get through peer review if you didn't + + + align:start position:0% +get through peer review if you didn't +take care of that problem + + align:start position:0% +take care of that problem + + + align:start position:0% +take care of that problem +okay okay so that's the first thing + + align:start position:0% +okay okay so that's the first thing + + + align:start position:0% +okay okay so that's the first thing +here's another even more radical example + + align:start position:0% +here's another even more radical example + + + align:start position:0% +here's another even more radical example +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so people have shown that grid-like + + align:start position:0% +so people have shown that grid-like + + + align:start position:0% +so people have shown that grid-like +representations and i'm skipping over + + align:start position:0% +representations and i'm skipping over + + + align:start position:0% +representations and i'm skipping over +most of the details here to give you the + + align:start position:0% +most of the details here to give you the + + + align:start position:0% +most of the details here to give you the +gist because actually the details are a + + align:start position:0% +gist because actually the details are a + + + align:start position:0% +gist because actually the details are a +bit complicated + + align:start position:0% +bit complicated + + + align:start position:0% +bit complicated +but they've shown that people seem to + + align:start position:0% +but they've shown that people seem to + + + align:start position:0% +but they've shown that people seem to +use their grid cell system + + align:start position:0% +use their grid cell system + + + align:start position:0% +use their grid cell system +when they are thinking about conceptual + + align:start position:0% +when they are thinking about conceptual + + + align:start position:0% +when they are thinking about conceptual +spaces + + align:start position:0% +spaces + + + align:start position:0% +spaces +not just physical spaces + + align:start position:0% +not just physical spaces + + + align:start position:0% +not just physical spaces +okay so there's one classic experiment + + align:start position:0% +okay so there's one classic experiment + + + align:start position:0% +okay so there's one classic experiment +in which these guys taught subjects a + + align:start position:0% +in which these guys taught subjects a + + + align:start position:0% +in which these guys taught subjects a +conceptual space they taught them about + + align:start position:0% +conceptual space they taught them about + + + align:start position:0% +conceptual space they taught them about +different kinds of birds + + align:start position:0% +different kinds of birds + + + align:start position:0% +different kinds of birds +okay and these birds differed on two + + align:start position:0% +okay and these birds differed on two + + + align:start position:0% +okay and these birds differed on two +dimensions + + align:start position:0% +dimensions + + + align:start position:0% +dimensions +they could vary in neck length or in leg + + align:start position:0% +they could vary in neck length or in leg + + + align:start position:0% +they could vary in neck length or in leg +length and these things were + + align:start position:0% +length and these things were + + + align:start position:0% +length and these things were +orthogonally varied so they made some + + align:start position:0% +orthogonally varied so they made some + + + align:start position:0% +orthogonally varied so they made some +artificial birds that kind of filled up + + align:start position:0% +artificial birds that kind of filled up + + + align:start position:0% +artificial birds that kind of filled up +that space + + align:start position:0% +that space + + + align:start position:0% +that space +okay so here are some of the birds this + + align:start position:0% +okay so here are some of the birds this + + + align:start position:0% +okay so here are some of the birds this +one has short legs and okay here's + + align:start position:0% +one has short legs and okay here's + + + align:start position:0% +one has short legs and okay here's +here's one with short legs and a long + + align:start position:0% +here's one with short legs and a long + + + align:start position:0% +here's one with short legs and a long +neck + + align:start position:0% +neck + + + align:start position:0% +neck +and um here's one with a longer neck and + + align:start position:0% +and um here's one with a longer neck and + + + align:start position:0% +and um here's one with a longer neck and +shorter leg uh wait let's see longer + + align:start position:0% +shorter leg uh wait let's see longer + + + align:start position:0% +shorter leg uh wait let's see longer +legs and shorter neck right there okay + + align:start position:0% +legs and shorter neck right there okay + + + align:start position:0% +legs and shorter neck right there okay +so you got every possible combination + + align:start position:0% +so you got every possible combination + + + align:start position:0% +so you got every possible combination +they didn't show people a space like + + align:start position:0% +they didn't show people a space like + + + align:start position:0% +they didn't show people a space like +that they just taught them um things + + align:start position:0% +that they just taught them um things + + + align:start position:0% +that they just taught them um things +about these different birds they had to + + align:start position:0% +about these different birds they had to + + + align:start position:0% +about these different birds they had to +remember their names and various facts + + align:start position:0% +remember their names and various facts + + + align:start position:0% +remember their names and various facts +about them + + align:start position:0% +about them + + + align:start position:0% +about them +and so the idea is that when people + + align:start position:0% +and so the idea is that when people + + + align:start position:0% +and so the idea is that when people +learn about those birds they + + align:start position:0% +learn about those birds they + + + align:start position:0% +learn about those birds they +mentally construct a 2d space because in + + align:start position:0% +mentally construct a 2d space because in + + + align:start position:0% +mentally construct a 2d space because in +fact those birds + + align:start position:0% +fact those birds + + + align:start position:0% +fact those birds +were generated from a 2d space varying + + align:start position:0% +were generated from a 2d space varying + + + align:start position:0% +were generated from a 2d space varying +neck length and leg length + + align:start position:0% +neck length and leg length + + + align:start position:0% +neck length and leg length +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and so then when they scan subjects + + align:start position:0% +and so then when they scan subjects + + + align:start position:0% +and so then when they scan subjects +they + + align:start position:0% +they + + + align:start position:0% +they +found essentially a neural signature of + + align:start position:0% +found essentially a neural signature of + + + align:start position:0% +found essentially a neural signature of +a grid system + + align:start position:0% +a grid system + + + align:start position:0% +a grid system +representing that 2d space + + align:start position:0% +representing that 2d space + + + align:start position:0% +representing that 2d space +so even though the grid system + + align:start position:0% +so even though the grid system + + + align:start position:0% +so even though the grid system +presumably evolved to enable us to + + align:start position:0% +presumably evolved to enable us to + + + align:start position:0% +presumably evolved to enable us to +navigate around in a 2d space and keep + + align:start position:0% +navigate around in a 2d space and keep + + + align:start position:0% +navigate around in a 2d space and keep +track of where we are in that 2d space + + align:start position:0% +track of where we are in that 2d space + + + align:start position:0% +track of where we are in that 2d space +it seems like it's now getting co-opted + + align:start position:0% +it seems like it's now getting co-opted + + + align:start position:0% +it seems like it's now getting co-opted +and being used for all kinds of + + align:start position:0% +and being used for all kinds of + + + align:start position:0% +and being used for all kinds of +representations of 2d spaces including + + align:start position:0% +representations of 2d spaces including + + + align:start position:0% +representations of 2d spaces including +extremely abstract artificial learned 2d + + align:start position:0% +extremely abstract artificial learned 2d + + + align:start position:0% +extremely abstract artificial learned 2d +spaces that you weren't even taught + + align:start position:0% +spaces that you weren't even taught + + + align:start position:0% +spaces that you weren't even taught +explicitly as a 2d space you were just + + align:start position:0% +explicitly as a 2d space you were just + + + align:start position:0% +explicitly as a 2d space you were just +taught these birds okay + + align:start position:0% + + + + align:start position:0% + +so that's pretty amazing + + align:start position:0% +so that's pretty amazing + + + align:start position:0% +so that's pretty amazing +in another recent study they had + + align:start position:0% +in another recent study they had + + + align:start position:0% +in another recent study they had +subjects + + align:start position:0% +subjects + + + align:start position:0% +subjects +play a do a role playing game + + align:start position:0% +play a do a role playing game + + + align:start position:0% +play a do a role playing game +while in the scanner in the role-playing + + align:start position:0% +while in the scanner in the role-playing + + + align:start position:0% +while in the scanner in the role-playing +game they're interacting with virtual + + align:start position:0% +game they're interacting with virtual + + + align:start position:0% +game they're interacting with virtual +characters + + align:start position:0% +characters + + + align:start position:0% +characters +and those virtual characters had um + + align:start position:0% +and those virtual characters had um + + + align:start position:0% +and those virtual characters had um +different kinds of social power and + + align:start position:0% +different kinds of social power and + + + align:start position:0% +different kinds of social power and +different affiliations with other + + align:start position:0% +different affiliations with other + + + align:start position:0% +different affiliations with other +individuals + + align:start position:0% +individuals + + + align:start position:0% +individuals +so here's another + + align:start position:0% +so here's another + + + align:start position:0% +so here's another +um kind of so the social space that was + + align:start position:0% +um kind of so the social space that was + + + align:start position:0% +um kind of so the social space that was +kind of invented by the experiment + + align:start position:0% +kind of invented by the experiment + + + align:start position:0% +kind of invented by the experiment +experimenters and the subjects are + + align:start position:0% +experimenters and the subjects are + + + align:start position:0% +experimenters and the subjects are +playing this game interacting with other + + align:start position:0% +playing this game interacting with other + + + align:start position:0% +playing this game interacting with other +virtual individuals who vary in social + + align:start position:0% +virtual individuals who vary in social + + + align:start position:0% +virtual individuals who vary in social +dominance and uh and their affiliation + + align:start position:0% +dominance and uh and their affiliation + + + align:start position:0% +dominance and uh and their affiliation +to to others + + align:start position:0% +to to others + + + align:start position:0% +to to others +and they find + + align:start position:0% +and they find + + + align:start position:0% +and they find +um place cell activity that seems to + + align:start position:0% +um place cell activity that seems to + + + align:start position:0% +um place cell activity that seems to +echo + + align:start position:0% +echo + + + align:start position:0% +echo +uh the position of another person + + align:start position:0% +uh the position of another person + + + align:start position:0% +uh the position of another person +in that social space and that's + + align:start position:0% +in that social space and that's + + + align:start position:0% +in that social space and that's +extremely abstract and yet again + + align:start position:0% +extremely abstract and yet again + + + align:start position:0% +extremely abstract and yet again +parts of the navigation spatial system + + align:start position:0% +parts of the navigation spatial system + + + align:start position:0% +parts of the navigation spatial system +are being co-opted to do this i'm not + + align:start position:0% +are being co-opted to do this i'm not + + + align:start position:0% +are being co-opted to do this i'm not +giving you the details on how all this + + align:start position:0% +giving you the details on how all this + + + align:start position:0% +giving you the details on how all this +is done i'm just telling you that this + + align:start position:0% +is done i'm just telling you that this + + + align:start position:0% +is done i'm just telling you that this +studies have shown that these systems + + align:start position:0% +studies have shown that these systems + + + align:start position:0% +studies have shown that these systems +are being co-opted for other uses + + align:start position:0% +are being co-opted for other uses + + + align:start position:0% +are being co-opted for other uses +here's another very charming + + align:start position:0% +here's another very charming + + + align:start position:0% +here's another very charming +non-spatial use well sort of spatial use + + align:start position:0% +non-spatial use well sort of spatial use + + + align:start position:0% +non-spatial use well sort of spatial use +of place cells so those bats turns out + + align:start position:0% +of place cells so those bats turns out + + + align:start position:0% +of place cells so those bats turns out +are extremely social organisms they have + + align:start position:0% +are extremely social organisms they have + + + align:start position:0% +are extremely social organisms they have +very sophisticated social structures and + + align:start position:0% +very sophisticated social structures and + + + align:start position:0% +very sophisticated social structures and +they care a lot about each other and + + align:start position:0% +they care a lot about each other and + + + align:start position:0% +they care a lot about each other and +who's related to whom and who's doing + + align:start position:0% +who's related to whom and who's doing + + + align:start position:0% +who's related to whom and who's doing +what to whom + + align:start position:0% +what to whom + + + align:start position:0% +what to whom +and it turns out that um there are + + align:start position:0% +and it turns out that um there are + + + align:start position:0% +and it turns out that um there are +social place cells in bats that is cells + + align:start position:0% +social place cells in bats that is cells + + + align:start position:0% +social place cells in bats that is cells +in this bats brain if i were a vat that + + align:start position:0% +in this bats brain if i were a vat that + + + align:start position:0% +in this bats brain if i were a vat that +would be representing your location jack + + align:start position:0% +would be representing your location jack + + + align:start position:0% +would be representing your location jack +okay so not the usual thing where my + + align:start position:0% +okay so not the usual thing where my + + + align:start position:0% +okay so not the usual thing where my +place cells are just saying where am i + + align:start position:0% +place cells are just saying where am i + + + align:start position:0% +place cells are just saying where am i +i'm watching you and my place starts out + + align:start position:0% +i'm watching you and my place starts out + + + align:start position:0% +i'm watching you and my place starts out +telling me where are you + + align:start position:0% +telling me where are you + + + align:start position:0% +telling me where are you +right something social organisms care a + + align:start position:0% +right something social organisms care a + + + align:start position:0% +right something social organisms care a +lot about including bats so they have + + align:start position:0% +lot about including bats so they have + + + align:start position:0% +lot about including bats so they have +an observer bat here hanging upside down + + align:start position:0% +an observer bat here hanging upside down + + + align:start position:0% +an observer bat here hanging upside down +and he's watching this bat fly over to + + align:start position:0% +and he's watching this bat fly over to + + + align:start position:0% +and he's watching this bat fly over to +there and back and then in this + + align:start position:0% +there and back and then in this + + + align:start position:0% +there and back and then in this +experiment he subsequently flies that + + align:start position:0% +experiment he subsequently flies that + + + align:start position:0% +experiment he subsequently flies that +same path that's how we know that he's + + align:start position:0% +same path that's how we know that he's + + + align:start position:0% +same path that's how we know that he's +watching that path because he has to + + align:start position:0% +watching that path because he has to + + + align:start position:0% +watching that path because he has to +mimic the bat's path that he just + + align:start position:0% +mimic the bat's path that he just + + + align:start position:0% +mimic the bat's path that he just +observed but while he's watching that + + align:start position:0% +observed but while he's watching that + + + align:start position:0% +observed but while he's watching that +bat + + align:start position:0% +bat + + + align:start position:0% +bat +fly on that path + + align:start position:0% +fly on that path + + + align:start position:0% +fly on that path +what you see is here's a cell right here + + align:start position:0% +what you see is here's a cell right here + + + align:start position:0% +what you see is here's a cell right here +here is um the path flown uh by the bat + + align:start position:0% +here is um the path flown uh by the bat + + + align:start position:0% +here is um the path flown uh by the bat +like out and back + + align:start position:0% +like out and back + + + align:start position:0% +like out and back +um and this is when the bat is flying + + align:start position:0% +um and this is when the bat is flying + + + align:start position:0% +um and this is when the bat is flying +out and back himself and this is when + + align:start position:0% +out and back himself and this is when + + + align:start position:0% +out and back himself and this is when +the other bat is flying out and back + + align:start position:0% +the other bat is flying out and back + + + align:start position:0% +the other bat is flying out and back +blurred a little bit here's here's the + + align:start position:0% +blurred a little bit here's here's the + + + align:start position:0% +blurred a little bit here's here's the +place field for self and the place field + + align:start position:0% +place field for self and the place field + + + align:start position:0% +place field for self and the place field +for other they're not the same a given + + align:start position:0% +for other they're not the same a given + + + align:start position:0% +for other they're not the same a given +cell doesn't represent the same location + + align:start position:0% +cell doesn't represent the same location + + + align:start position:0% +cell doesn't represent the same location +when it's me who's there and when it's + + align:start position:0% +when it's me who's there and when it's + + + align:start position:0% +when it's me who's there and when it's +the person or bad i'm watching who's + + align:start position:0% +the person or bad i'm watching who's + + + align:start position:0% +the person or bad i'm watching who's +there right + + align:start position:0% +there right + + + align:start position:0% +there right +but there are place fields in both cases + + align:start position:0% +but there are place fields in both cases + + + align:start position:0% +but there are place fields in both cases +right + + align:start position:0% + + + + align:start position:0% + +social place cells + + align:start position:0% +social place cells + + + align:start position:0% +social place cells +okay + + align:start position:0% +okay + + + align:start position:0% +okay +i'm going to keep going because + + align:start position:0% +i'm going to keep going because + + + align:start position:0% +i'm going to keep going because +otherwise i'm going to run out of time + + align:start position:0% +otherwise i'm going to run out of time + + + align:start position:0% +otherwise i'm going to run out of time +but i'll hang around after + + align:start position:0% +but i'll hang around after + + + align:start position:0% +but i'll hang around after +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so + + align:start position:0% +so + + + align:start position:0% +so +place this this whole system is used uh + + align:start position:0% +place this this whole system is used uh + + + align:start position:0% +place this this whole system is used uh +not just for representing + + align:start position:0% +not just for representing + + + align:start position:0% +not just for representing +social status + + align:start position:0% +social status + + + align:start position:0% +social status +you know what kind of bird this is in + + align:start position:0% +you know what kind of bird this is in + + + align:start position:0% +you know what kind of bird this is in +this abstract bird space + + align:start position:0% +this abstract bird space + + + align:start position:0% +this abstract bird space +uh but actually for making decisions for + + align:start position:0% +uh but actually for making decisions for + + + align:start position:0% +uh but actually for making decisions for +thinking okay so + + align:start position:0% +thinking okay so + + + align:start position:0% +thinking okay so +as rats run in mazes + + align:start position:0% +as rats run in mazes + + + align:start position:0% +as rats run in mazes +you can you can record we've shown this + + align:start position:0% +you can you can record we've shown this + + + align:start position:0% +you can you can record we've shown this +already you can show multiple + + align:start position:0% +already you can show multiple + + + align:start position:0% +already you can show multiple +hippocampal place cells and can you guys + + align:start position:0% +hippocampal place cells and can you guys + + + align:start position:0% +hippocampal place cells and can you guys +imagine that if we were recording from + + align:start position:0% +imagine that if we were recording from + + + align:start position:0% +imagine that if we were recording from +several different hippocampal cells at + + align:start position:0% +several different hippocampal cells at + + + align:start position:0% +several different hippocampal cells at +the same time + + align:start position:0% +the same time + + + align:start position:0% +the same time +we could read out those cells and make a + + align:start position:0% +we could read out those cells and make a + + + align:start position:0% +we could read out those cells and make a +guess about where the rat is in its + + align:start position:0% +guess about where the rat is in its + + + align:start position:0% +guess about where the rat is in its +location right it's just like mvpa but + + align:start position:0% +location right it's just like mvpa but + + + align:start position:0% +location right it's just like mvpa but +done across neurons right so we have + + align:start position:0% +done across neurons right so we have + + + align:start position:0% +done across neurons right so we have +pretty good sense of where the where the + + align:start position:0% +pretty good sense of where the where the + + + align:start position:0% +pretty good sense of where the where the +rat is okay + + align:start position:0% +rat is okay + + + align:start position:0% +rat is okay +so + + align:start position:0% +so + + + align:start position:0% +so +now we have a rat navigating around in + + align:start position:0% +now we have a rat navigating around in + + + align:start position:0% +now we have a rat navigating around in +this maze and what i'm going to show you + + align:start position:0% +this maze and what i'm going to show you + + + align:start position:0% +this maze and what i'm going to show you +the white circle is where the rat + + align:start position:0% +the white circle is where the rat + + + align:start position:0% +the white circle is where the rat +actually is + + align:start position:0% +actually is + + + align:start position:0% +actually is +and the little color thing is telling + + align:start position:0% +and the little color thing is telling + + + align:start position:0% +and the little color thing is telling +you where the simultaneous readout from + + align:start position:0% +you where the simultaneous readout from + + + align:start position:0% +you where the simultaneous readout from +several place cells in that rat's + + align:start position:0% +several place cells in that rat's + + + align:start position:0% +several place cells in that rat's +hippocampus + + align:start position:0% +hippocampus + + + align:start position:0% +hippocampus +um would would predict where the rat is + + align:start position:0% +um would would predict where the rat is + + + align:start position:0% +um would would predict where the rat is +like can we tell where the rat is by + + align:start position:0% +like can we tell where the rat is by + + + align:start position:0% +like can we tell where the rat is by +looking at us place cells okay so right + + align:start position:0% +looking at us place cells okay so right + + + align:start position:0% +looking at us place cells okay so right +here they're in the same place it makes + + align:start position:0% +here they're in the same place it makes + + + align:start position:0% +here they're in the same place it makes +sense the rat is right there and we're + + align:start position:0% +sense the rat is right there and we're + + + align:start position:0% +sense the rat is right there and we're +reading it out + + align:start position:0% +reading it out + + + align:start position:0% +reading it out +okay so far so good + + align:start position:0% +okay so far so good + + + align:start position:0% +okay so far so good +but now what we're going to do + + align:start position:0% +but now what we're going to do + + + align:start position:0% +but now what we're going to do +is watch what that place cell location + + align:start position:0% +is watch what that place cell location + + + align:start position:0% +is watch what that place cell location +does as the rat moves around in his + + align:start position:0% +does as the rat moves around in his + + + align:start position:0% +does as the rat moves around in his +environment and makes decisions about + + align:start position:0% +environment and makes decisions about + + + align:start position:0% +environment and makes decisions about +where to go next + + align:start position:0% +where to go next + + + align:start position:0% +where to go next +okay + + align:start position:0% +okay + + + align:start position:0% +okay +okay so what we're going to see is the + + align:start position:0% +okay so what we're going to see is the + + + align:start position:0% +okay so what we're going to see is the +rat is going to come up to an + + align:start position:0% +rat is going to come up to an + + + align:start position:0% +rat is going to come up to an +intersection of the maze i think it's + + align:start position:0% +intersection of the maze i think it's + + + align:start position:0% +intersection of the maze i think it's +that in that i think it's right here + + align:start position:0% +that in that i think it's right here + + + align:start position:0% +that in that i think it's right here +and he's going to decide am i going to + + align:start position:0% +and he's going to decide am i going to + + + align:start position:0% +and he's going to decide am i going to +go this way am i going to go that way + + align:start position:0% +go this way am i going to go that way + + + align:start position:0% +go this way am i going to go that way +and as the rat stays there deciding + + align:start position:0% +and as the rat stays there deciding + + + align:start position:0% +and as the rat stays there deciding +which way to go and the white dot stays + + align:start position:0% +which way to go and the white dot stays + + + align:start position:0% +which way to go and the white dot stays +there as he sits there thinking huh + + align:start position:0% +there as he sits there thinking huh + + + align:start position:0% +there as he sits there thinking huh +should i do this should i do that you + + align:start position:0% +should i do this should i do that you + + + align:start position:0% +should i do this should i do that you +could call it neural deliberation we + + align:start position:0% +could call it neural deliberation we + + + align:start position:0% +could call it neural deliberation we +will see what his place cell activity + + align:start position:0% +will see what his place cell activity + + + align:start position:0% +will see what his place cell activity +shows you + + align:start position:0% +shows you + + + align:start position:0% +shows you +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so here we go + + align:start position:0% +so here we go + + + align:start position:0% +so here we go +rat starts there whoops how do i play + + align:start position:0% +rat starts there whoops how do i play + + + align:start position:0% +rat starts there whoops how do i play +this here + + align:start position:0% + + + + align:start position:0% + +okay so rad is heading up there and so + + align:start position:0% +okay so rad is heading up there and so + + + align:start position:0% +okay so rad is heading up there and so +are his place cells he comes up to the + + align:start position:0% +are his place cells he comes up to the + + + align:start position:0% +are his place cells he comes up to the +intersection + + align:start position:0% +intersection + + + align:start position:0% +intersection +he stays in one place but look what his + + align:start position:0% +he stays in one place but look what his + + + align:start position:0% +he stays in one place but look what his +place cells are doing should i go over + + align:start position:0% +place cells are doing should i go over + + + align:start position:0% +place cells are doing should i go over +there + + align:start position:0% +there + + + align:start position:0% +there +i'm just interpreting what this means + + align:start position:0% +i'm just interpreting what this means + + + align:start position:0% +i'm just interpreting what this means +but it sure looks like neural + + align:start position:0% +but it sure looks like neural + + + align:start position:0% +but it sure looks like neural +deliberation to me + + align:start position:0% +deliberation to me + + + align:start position:0% +deliberation to me +and that's what he decided everybody get + + align:start position:0% +and that's what he decided everybody get + + + align:start position:0% +and that's what he decided everybody get +what we just saw + + align:start position:0% +what we just saw + + + align:start position:0% +what we just saw +he while he's standing there he's in one + + align:start position:0% +he while he's standing there he's in one + + + align:start position:0% +he while he's standing there he's in one +place but he's clearly deciding where to + + align:start position:0% +place but he's clearly deciding where to + + + align:start position:0% +place but he's clearly deciding where to +go next and while he's deciding those + + align:start position:0% +go next and while he's deciding those + + + align:start position:0% +go next and while he's deciding those +place cells are + + align:start position:0% +place cells are + + + align:start position:0% +place cells are +essentially apparently running + + align:start position:0% +essentially apparently running + + + align:start position:0% +essentially apparently running +simulations of where he might go next + + align:start position:0% + + + + align:start position:0% + +okay so we started with this big long + + align:start position:0% +okay so we started with this big long + + + align:start position:0% +okay so we started with this big long +list of things you need to know to + + align:start position:0% +list of things you need to know to + + + align:start position:0% +list of things you need to know to +navigate around in the world and the + + align:start position:0% +navigate around in the world and the + + + align:start position:0% +navigate around in the world and the +neural basis of all this is really not + + align:start position:0% +neural basis of all this is really not + + + align:start position:0% +neural basis of all this is really not +understood yet but i've shown you what i + + align:start position:0% +understood yet but i've shown you what i + + + align:start position:0% +understood yet but i've shown you what i +think are a bunch of + + align:start position:0% +think are a bunch of + + + align:start position:0% +think are a bunch of +tantalizing snippets + + align:start position:0% +tantalizing snippets + + + align:start position:0% +tantalizing snippets +um which lead to the idea that our best + + align:start position:0% +um which lead to the idea that our best + + + align:start position:0% +um which lead to the idea that our best +current guess about the kind of neural + + align:start position:0% +current guess about the kind of neural + + + align:start position:0% +current guess about the kind of neural +locus of these things which is very far + + align:start position:0% +locus of these things which is very far + + + align:start position:0% +locus of these things which is very far +from the actual understanding of how + + align:start position:0% +from the actual understanding of how + + + align:start position:0% +from the actual understanding of how +they work + + align:start position:0% +they work + + + align:start position:0% +they work +is that the perception of the layout of + + align:start position:0% +is that the perception of the layout of + + + align:start position:0% +is that the perception of the layout of +space around us the ppa and the + + align:start position:0% +space around us the ppa and the + + + align:start position:0% +space around us the ppa and the +occipital place area are very involved + + align:start position:0% +occipital place area are very involved + + + align:start position:0% +occipital place area are very involved +in that + + align:start position:0% +in that + + + align:start position:0% +in that +also + + align:start position:0% +also + + + align:start position:0% +also +in saying for an unfamiliar place what + + align:start position:0% +in saying for an unfamiliar place what + + + align:start position:0% +in saying for an unfamiliar place what +kind of place is this i didn't show you + + align:start position:0% +kind of place is this i didn't show you + + + align:start position:0% +kind of place is this i didn't show you +those data but you can in fact decode + + align:start position:0% +those data but you can in fact decode + + + align:start position:0% +those data but you can in fact decode +whether you're looking at a scene or a + + align:start position:0% +whether you're looking at a scene or a + + + align:start position:0% +whether you're looking at a scene or a +beach by looking at the pattern of + + align:start position:0% +beach by looking at the pattern of + + + align:start position:0% +beach by looking at the pattern of +response in the ppa + + align:start position:0% +response in the ppa + + + align:start position:0% +response in the ppa +we talked about the idea that the + + align:start position:0% +we talked about the idea that the + + + align:start position:0% +we talked about the idea that the +retrosplenial cortex may be involved in + + align:start position:0% +retrosplenial cortex may be involved in + + + align:start position:0% +retrosplenial cortex may be involved in +recognizing familiar locations that's a + + align:start position:0% +recognizing familiar locations that's a + + + align:start position:0% +recognizing familiar locations that's a +bit of a question mark + + align:start position:0% +bit of a question mark + + + align:start position:0% +bit of a question mark +that the idea that your map of the world + + align:start position:0% +that the idea that your map of the world + + + align:start position:0% +that the idea that your map of the world +is represented in your hippocampus by + + align:start position:0% +is represented in your hippocampus by + + + align:start position:0% +is represented in your hippocampus by +way of place cells which also say where + + align:start position:0% +way of place cells which also say where + + + align:start position:0% +way of place cells which also say where +you are in that world + + align:start position:0% +you are in that world + + + align:start position:0% +you are in that world +that you're heading direction in humans + + align:start position:0% +that you're heading direction in humans + + + align:start position:0% +that you're heading direction in humans +i didn't give you all the evidence for + + align:start position:0% +i didn't give you all the evidence for + + + align:start position:0% +i didn't give you all the evidence for +this but in humans there's quite a bit + + align:start position:0% +this but in humans there's quite a bit + + + align:start position:0% +this but in humans there's quite a bit +of evidence that retrosplenial cortex is + + align:start position:0% +of evidence that retrosplenial cortex is + + + align:start position:0% +of evidence that retrosplenial cortex is +very involved in heading direction i + + align:start position:0% +very involved in heading direction i + + + align:start position:0% +very involved in heading direction i +guess i did give you evidence patients + + align:start position:0% +guess i did give you evidence patients + + + align:start position:0% +guess i did give you evidence patients +who have had damage there and can + + align:start position:0% +who have had damage there and can + + + align:start position:0% +who have had damage there and can +recognize places but not know how + + align:start position:0% +recognize places but not know how + + + align:start position:0% +recognize places but not know how +they're oriented there + + align:start position:0% +they're oriented there + + + align:start position:0% +they're oriented there +that planning routes around boundaries + + align:start position:0% +that planning routes around boundaries + + + align:start position:0% +that planning routes around boundaries +in your environment uh involves the + + align:start position:0% +in your environment uh involves the + + + align:start position:0% +in your environment uh involves the +occipital place area and the peripheral + + align:start position:0% +occipital place area and the peripheral + + + align:start position:0% +occipital place area and the peripheral +campbell place area + + align:start position:0% +campbell place area + + + align:start position:0% +campbell place area +and that this business of reorientation + + align:start position:0% +and that this business of reorientation + + + align:start position:0% +and that this business of reorientation +seems to particularly involve + + align:start position:0% +seems to particularly involve + + + align:start position:0% +seems to particularly involve +heading direction cells in humans most + + align:start position:0% +heading direction cells in humans most + + + align:start position:0% +heading direction cells in humans most +likely in retrospective cortex + + align:start position:0% +likely in retrospective cortex + + + align:start position:0% +likely in retrospective cortex +so you don't need to memorize all that i + + align:start position:0% +so you don't need to memorize all that i + + + align:start position:0% +so you don't need to memorize all that i +mean you know i don't care that much + + align:start position:0% +mean you know i don't care that much + + + align:start position:0% +mean you know i don't care that much +about the locations what i want you guys + + align:start position:0% +about the locations what i want you guys + + + align:start position:0% +about the locations what i want you guys +to understand is what are these problems + + align:start position:0% +to understand is what are these problems + + + align:start position:0% +to understand is what are these problems +that are involved in navigation and what + + align:start position:0% +that are involved in navigation and what + + + align:start position:0% +that are involved in navigation and what +kinds of things can we learn with + + align:start position:0% +kinds of things can we learn with + + + align:start position:0% +kinds of things can we learn with +different kinds of behavioral and neural + + align:start position:0% +different kinds of behavioral and neural + + + align:start position:0% +different kinds of behavioral and neural +measures and you may have noticed in the + + align:start position:0% +measures and you may have noticed in the + + + align:start position:0% +measures and you may have noticed in the +last couple lectures that i presented + + align:start position:0% +last couple lectures that i presented + + + align:start position:0% +last couple lectures that i presented +lots of behavioral data because actually + + align:start position:0% +lots of behavioral data because actually + + + align:start position:0% +lots of behavioral data because actually +so far the richest insights about how + + align:start position:0% +so far the richest insights about how + + + align:start position:0% +so far the richest insights about how +the system actually works still come or + + align:start position:0% +the system actually works still come or + + + align:start position:0% +the system actually works still come or +many of the rich ones come from + + align:start position:0% +many of the rich ones come from + + + align:start position:0% +many of the rich ones come from +behavioral data okay quiz is in two + + align:start position:0% +behavioral data okay quiz is in two + + + align:start position:0% +behavioral data okay quiz is in two +minutes does anybody want to ask me a + + align:start position:0% +minutes does anybody want to ask me a + + + align:start position:0% +minutes does anybody want to ask me a +question before the quiz + + align:start position:0% + + + + align:start position:0% + +yeah so you have to do lots of controls + + align:start position:0% +yeah so you have to do lots of controls + + + align:start position:0% +yeah so you have to do lots of controls +to to work that out and i didn't show + + align:start position:0% +to to work that out and i didn't show + + + align:start position:0% +to to work that out and i didn't show +you any of the you know details of the + + align:start position:0% +you any of the you know details of the + + + align:start position:0% +you any of the you know details of the +data uh but yeah these guys are pretty + + align:start position:0% +data uh but yeah these guys are pretty + + + align:start position:0% +data uh but yeah these guys are pretty +careful and there are all these things + + align:start position:0% +careful and there are all these things + + + align:start position:0% +careful and there are all these things +there are many different ways in which + + align:start position:0% +there are many different ways in which + + + align:start position:0% +there are many different ways in which +people are watching + + align:start position:0% +people are watching + + + align:start position:0% +people are watching +neuro + + align:start position:0% +neuro + + + align:start position:0% +neuro +watching hippocampal neurons and + + align:start position:0% +watching hippocampal neurons and + + + align:start position:0% +watching hippocampal neurons and +decoding trajectories from hippocampal + + align:start position:0% +decoding trajectories from hippocampal + + + align:start position:0% +decoding trajectories from hippocampal +neurons + + align:start position:0% +neurons + + + align:start position:0% +neurons +you may have heard about replay which is + + align:start position:0% +you may have heard about replay which is + + + align:start position:0% +you may have heard about replay which is +like a big thing in this department + + align:start position:0% +like a big thing in this department + + + align:start position:0% +like a big thing in this department +tanagawa and wilson labs study this + + align:start position:0% +tanagawa and wilson labs study this + + + align:start position:0% +tanagawa and wilson labs study this +where you have a rodent moving around in + + align:start position:0% +where you have a rodent moving around in + + + align:start position:0% +where you have a rodent moving around in +one trajectory + + align:start position:0% +one trajectory + + + align:start position:0% +one trajectory +during the day and then you record from + + align:start position:0% +during the day and then you record from + + + align:start position:0% +during the day and then you record from +those neurons at night and you see + + align:start position:0% +those neurons at night and you see + + + align:start position:0% +those neurons at night and you see +replay of the trajectories that the + + align:start position:0% +replay of the trajectories that the + + + align:start position:0% +replay of the trajectories that the +rodent went through in the previous day + + align:start position:0% +rodent went through in the previous day + + + align:start position:0% +rodent went through in the previous day +and so there you have to be really + + align:start position:0% +and so there you have to be really + + + align:start position:0% +and so there you have to be really +careful to say okay there's a lot of + + align:start position:0% +careful to say okay there's a lot of + + + align:start position:0% +careful to say okay there's a lot of +data and a lot of noise and is this + + align:start position:0% +data and a lot of noise and is this + + + align:start position:0% +data and a lot of noise and is this +really more than the noise and it is but + + align:start position:0% +really more than the noise and it is but + + + align:start position:0% +really more than the noise and it is but +it takes a lot of statistical work to + + align:start position:0% +it takes a lot of statistical work to + + + align:start position:0% +it takes a lot of statistical work to +show that + + align:start position:0% +show that + + + align:start position:0% +show that +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +scenario um say like a place that i know + + align:start position:0% +scenario um say like a place that i know + + + align:start position:0% +scenario um say like a place that i know +yeah uh with the nuance + + align:start position:0% +yeah uh with the nuance + + + align:start position:0% +yeah uh with the nuance +um the same neurons inspire if i go back + + align:start position:0% +um the same neurons inspire if i go back + + + align:start position:0% +um the same neurons inspire if i go back +to that environment i've assumed for + + align:start position:0% +to that environment i've assumed for + + + align:start position:0% +to that environment i've assumed for +like the truth yeah yeah + + align:start position:0% +like the truth yeah yeah + + + align:start position:0% +like the truth yeah yeah +but + + align:start position:0% +but + + + align:start position:0% +but +but then you can't really have that or + + align:start position:0% +but then you can't really have that or + + + align:start position:0% +but then you can't really have that or +like you can't be + + align:start position:0% +like you can't be + + + align:start position:0% +like you can't be +it's a good question how do we have + + align:start position:0% +it's a good question how do we have + + + align:start position:0% +it's a good question how do we have +enough neurons yeah especially for some + + align:start position:0% +enough neurons yeah especially for some + + + align:start position:0% +enough neurons yeah especially for some +place we go every six months are they + + align:start position:0% +place we go every six months are they + + + align:start position:0% +place we go every six months are they +sitting around waiting for us to go back + + align:start position:0% +sitting around waiting for us to go back + + + align:start position:0% +sitting around waiting for us to go back +there no there's some recycling of + + align:start position:0% +there no there's some recycling of + + + align:start position:0% +there no there's some recycling of +neurons across very different locations + + align:start position:0% +neurons across very different locations + + + align:start position:0% +neurons across very different locations +so within that location they'll be + + align:start position:0% +so within that location they'll be + + + align:start position:0% +so within that location they'll be +consistent but yes you do recycle so the + + align:start position:0% +consistent but yes you do recycle so the + + + align:start position:0% +consistent but yes you do recycle so the +same neuron will have one place cell in + + align:start position:0% +same neuron will have one place cell in + + + align:start position:0% +same neuron will have one place cell in +this environment and it may or may not + + align:start position:0% +this environment and it may or may not + + + align:start position:0% +this environment and it may or may not +have a place cell in another environment + + align:start position:0% +have a place cell in another environment + + + align:start position:0% +have a place cell in another environment +that's a good question + + align:start position:0% + + + + align:start position:0% + +you \ No newline at end of file diff --git a/pqkYqU11ETA.txt b/pqkYqU11ETA.txt new file mode 100644 index 0000000000000000000000000000000000000000..da511e0b096a5d039c2fca72fd3a31eca84cecbe --- /dev/null +++ b/pqkYqU11ETA.txt @@ -0,0 +1,7211 @@ +align:start position:0% + +The following content is provided under + + align:start position:0% +The following content is provided under + + + align:start position:0% +The following content is provided under +a Creative Common License. Your support + + align:start position:0% +a Creative Common License. Your support + + + align:start position:0% +a Creative Common License. Your support +will help MIT Open Courseware continue + + align:start position:0% +will help MIT Open Courseware continue + + + align:start position:0% +will help MIT Open Courseware continue +to offer high-quality educational + + align:start position:0% +to offer high-quality educational + + + align:start position:0% +to offer high-quality educational +resources for free. To make a donation + + align:start position:0% +resources for free. To make a donation + + + align:start position:0% +resources for free. To make a donation +or view additional materials from + + align:start position:0% +or view additional materials from + + + align:start position:0% +or view additional materials from +hundreds of MIT courses, visit MIT Open + + align:start position:0% +hundreds of MIT courses, visit MIT Open + + + align:start position:0% +hundreds of MIT courses, visit MIT Open +Courseware at + + align:start position:0% + + + + align:start position:0% + +ocw.mmit.edu. So today, what we've been + + align:start position:0% +ocw.mmit.edu. So today, what we've been + + + align:start position:0% +ocw.mmit.edu. So today, what we've been +doing, we've been looking at how there's + + align:start position:0% +doing, we've been looking at how there's + + + align:start position:0% +doing, we've been looking at how there's +a lot of different representations for + + align:start position:0% +a lot of different representations for + + + align:start position:0% +a lot of different representations for +CT systems. They look almost the same as + + align:start position:0% +CT systems. They look almost the same as + + + align:start position:0% +CT systems. They look almost the same as +a lot of representations for DT systems. + + align:start position:0% +a lot of representations for DT systems. + + + align:start position:0% +a lot of representations for DT systems. +And today I want to go one more step and + + align:start position:0% +And today I want to go one more step and + + + align:start position:0% +And today I want to go one more step and +show how there's actually a bunch of + + align:start position:0% +show how there's actually a bunch of + + + align:start position:0% +show how there's actually a bunch of +relationships between + + align:start position:0% +relationships between + + + align:start position:0% +relationships between +them. That's when things become very + + align:start position:0% +them. That's when things become very + + + align:start position:0% +them. That's when things become very +powerful. And so I want to do that by + + align:start position:0% +powerful. And so I want to do that by + + + align:start position:0% +powerful. And so I want to do that by +thinking about a very simple + + align:start position:0% +thinking about a very simple + + + align:start position:0% +thinking about a very simple +example. Thinking about a CT system and + + align:start position:0% +example. Thinking about a CT system and + + + align:start position:0% +example. Thinking about a CT system and +how you would convert that CT + + align:start position:0% +how you would convert that CT + + + align:start position:0% +how you would convert that CT +system into a DT representation. + + align:start position:0% +system into a DT representation. + + + align:start position:0% +system into a DT representation. +This is a problem we've worked on + + align:start position:0% +This is a problem we've worked on + + + align:start position:0% +This is a problem we've worked on +before, the leaky tank system. We've + + align:start position:0% +before, the leaky tank system. We've + + + align:start position:0% +before, the leaky tank system. We've +already seen a gazillion representations + + align:start position:0% +already seen a gazillion representations + + + align:start position:0% +already seen a gazillion representations +for + + align:start position:0% +for + + + align:start position:0% +for +it. We can think about the leaky ta tank + + align:start position:0% +it. We can think about the leaky ta tank + + + align:start position:0% +it. We can think about the leaky ta tank +system as a differential equation. We + + align:start position:0% +system as a differential equation. We + + + align:start position:0% +system as a differential equation. We +derived that in lecture + + align:start position:0% +derived that in lecture + + + align:start position:0% +derived that in lecture +one. We can think of it as a block + + align:start position:0% +one. We can think of it as a block + + + align:start position:0% +one. We can think of it as a block +diagram lecture one. We can think about + + align:start position:0% +diagram lecture one. We can think about + + + align:start position:0% +diagram lecture one. We can think about +it as a functional that was about two + + align:start position:0% +it as a functional that was about two + + + align:start position:0% +it as a functional that was about two +lectures ago as a system function that + + align:start position:0% +lectures ago as a system function that + + + align:start position:0% +lectures ago as a system function that +was lelass transforms that was about a + + align:start position:0% +was lelass transforms that was about a + + + align:start position:0% +was lelass transforms that was about a +week ago. We can think about an impulse + + align:start position:0% +week ago. We can think about an impulse + + + align:start position:0% +week ago. We can think about an impulse +response because the fundamental signal + + align:start position:0% +response because the fundamental signal + + + align:start position:0% +response because the fundamental signal +in CT, the thing that plays the same + + align:start position:0% +in CT, the thing that plays the same + + + align:start position:0% +in CT, the thing that plays the same +role as the unit sample in DT is the + + align:start position:0% +role as the unit sample in DT is the + + + align:start position:0% +role as the unit sample in DT is the +unit impulse. So we can think about the + + align:start position:0% +unit impulse. So we can think about the + + + align:start position:0% +unit impulse. So we can think about the +impulse response and there's a variety + + align:start position:0% +impulse response and there's a variety + + + align:start position:0% +impulse response and there's a variety +of connections between all of those. + + align:start position:0% +of connections between all of those. + + + align:start position:0% +of connections between all of those. +What I want to do today is compare the + + align:start position:0% +What I want to do today is compare the + + + align:start position:0% +What I want to do today is compare the +step response of the leaky tank system + + align:start position:0% +step response of the leaky tank system + + + align:start position:0% +step response of the leaky tank system +to the step + + align:start position:0% +to the step + + + align:start position:0% +to the step +response of a DT approximation to the + + align:start position:0% +response of a DT approximation to the + + + align:start position:0% +response of a DT approximation to the +leaky tank system. + + align:start position:0% +leaky tank system. + + + align:start position:0% +leaky tank system. +To get started then I want to figure out + + align:start position:0% +To get started then I want to figure out + + + align:start position:0% +To get started then I want to figure out +the step response of the leaky tank + + align:start position:0% +the step response of the leaky tank + + + align:start position:0% +the step response of the leaky tank +system for you. You should think about + + align:start position:0% +system for you. You should think about + + + align:start position:0% +system for you. You should think about +this as practice for the exam. You + + align:start position:0% +this as practice for the exam. You + + + align:start position:0% +this as practice for the exam. You +should be able to do this in 30 + + align:start position:0% +should be able to do this in 30 + + + align:start position:0% +should be able to do this in 30 +seconds. So start compare your answers + + align:start position:0% +seconds. So start compare your answers + + + align:start position:0% +seconds. So start compare your answers +to your neighbor. Figure out uh what is + + align:start position:0% +to your neighbor. Figure out uh what is + + + align:start position:0% +to your neighbor. Figure out uh what is +the step response for the leaky tank + + align:start position:0% +the step response for the leaky tank + + + align:start position:0% +the step response for the leaky tank +system. + + align:start position:0% + + + + align:start position:0% + +No, no. + + align:start position:0% + + + + align:start position:0% + +Okay, this question is too simple, so + + align:start position:0% +Okay, this question is too simple, so + + + align:start position:0% +Okay, this question is too simple, so +we're going to blast ahead. What's the + + align:start position:0% +we're going to blast ahead. What's the + + + align:start position:0% +we're going to blast ahead. What's the +answer? What's the step response for the + + align:start position:0% +answer? What's the step response for the + + + align:start position:0% +answer? What's the step response for the +leaky tank system? Everybody raise your + + align:start position:0% +leaky tank system? Everybody raise your + + + align:start position:0% +leaky tank system? Everybody raise your +hand. Let me see how many numbers. Okay, + + align:start position:0% +hand. Let me see how many numbers. Okay, + + + align:start position:0% +hand. Let me see how many numbers. Okay, +it's not quite as high a fraction as I + + align:start position:0% +it's not quite as high a fraction as I + + + align:start position:0% +it's not quite as high a fraction as I +would have liked. Uh, take another 15 + + align:start position:0% +would have liked. Uh, take another 15 + + + align:start position:0% +would have liked. Uh, take another 15 +seconds or better yet, talk to your + + align:start position:0% +seconds or better yet, talk to your + + + align:start position:0% +seconds or better yet, talk to your +neighbor. Explain your answer to your + + align:start position:0% +neighbor. Explain your answer to your + + + align:start position:0% +neighbor. Explain your answer to your +neighbor and let your neighbor tell you + + align:start position:0% +neighbor and let your neighbor tell you + + + align:start position:0% +neighbor and let your neighbor tell you +why you're wrong. + + align:start position:0% + + + + align:start position:0% + +Okay, + + align:start position:0% +Okay, + + + align:start position:0% +Okay, +revote. So, what's the step response of + + align:start position:0% +revote. So, what's the step response of + + + align:start position:0% +revote. So, what's the step response of +the leaky tank tank system? + + align:start position:0% +the leaky tank tank system? + + + align:start position:0% +the leaky tank tank system? +Better, better, better, better, better, + + align:start position:0% +Better, better, better, better, better, + + + align:start position:0% +Better, better, better, better, better, +better, better. Okay, almost 100%. Not + + align:start position:0% +better, better. Okay, almost 100%. Not + + + align:start position:0% +better, better. Okay, almost 100%. Not +quite. Another question. How many ways + + align:start position:0% +quite. Another question. How many ways + + + align:start position:0% +quite. Another question. How many ways +can you find the step response of the + + align:start position:0% +can you find the step response of the + + + align:start position:0% +can you find the step response of the +leaky tank system? One represents more + + align:start position:0% +leaky tank system? One represents more + + + align:start position:0% +leaky tank system? One represents more +than one. I'm not going to have a + + align:start position:0% +than one. I'm not going to have a + + + align:start position:0% +than one. I'm not going to have a +representation for zero, right? More + + align:start position:0% +representation for zero, right? More + + + align:start position:0% +representation for zero, right? More +than one, more than two, more than + + align:start position:0% +than one, more than two, more than + + + align:start position:0% +than one, more than two, more than +three, more than four, more than five. + + align:start position:0% +three, more than four, more than five. + + + align:start position:0% +three, more than four, more than five. +How many ways can you find + + align:start position:0% + + + + align:start position:0% + +that? Don't just stare at me with blank + + align:start position:0% +that? Don't just stare at me with blank + + + align:start position:0% +that? Don't just stare at me with blank +looks. + + align:start position:0% + + + + align:start position:0% + +Okay. What's a good way to find the step + + align:start position:0% +Okay. What's a good way to find the step + + + align:start position:0% +Okay. What's a good way to find the step +response of the + + align:start position:0% +response of the + + + align:start position:0% +response of the +system? You can shout. That way, I won't + + align:start position:0% +system? You can shout. That way, I won't + + + align:start position:0% +system? You can shout. That way, I won't +be able to identify where you're coming + + align:start position:0% +be able to identify where you're coming + + + align:start position:0% +be able to identify where you're coming +from, and I won't be able to point to + + align:start position:0% +from, and I won't be able to point to + + + align:start position:0% +from, and I won't be able to point to +you. But you have to be quick because if + + align:start position:0% +you. But you have to be quick because if + + + align:start position:0% +you. But you have to be quick because if +I see your mouth move, then I'll know + + align:start position:0% +I see your mouth move, then I'll know + + + align:start position:0% +I see your mouth move, then I'll know +which one you are. So, when I look this + + align:start position:0% +which one you are. So, when I look this + + + align:start position:0% +which one you are. So, when I look this +way, you shout over here, right? There's + + align:start position:0% +way, you shout over here, right? There's + + + align:start position:0% +way, you shout over here, right? There's +simple ways to do this, right? + + align:start position:0% +simple ways to do this, right? + + + align:start position:0% +simple ways to do this, right? +What's a good way to find the step + + align:start position:0% +What's a good way to find the step + + + align:start position:0% +What's a good way to find the step +response of of the leaky tank system? + + align:start position:0% +response of of the leaky tank system? + + + align:start position:0% +response of of the leaky tank system? +You have the transfer function + + align:start position:0% +You have the transfer function + + + align:start position:0% +You have the transfer function +multiplied with 1x then we have the + + align:start position:0% +multiplied with 1x then we have the + + + align:start position:0% +multiplied with 1x then we have the +trans that's a relatively advanced way + + align:start position:0% +trans that's a relatively advanced way + + + align:start position:0% +trans that's a relatively advanced way +and in completely correct. Could + + align:start position:0% +and in completely correct. Could + + + align:start position:0% +and in completely correct. Could +somebody tell me an even simpler way? + + align:start position:0% +somebody tell me an even simpler way? + + + align:start position:0% +somebody tell me an even simpler way? +Yes. What's the behavior as t goes to + + align:start position:0% +Yes. What's the behavior as t goes to + + + align:start position:0% +Yes. What's the behavior as t goes to +infinity? Okay. What is it? If I'm if I + + align:start position:0% +infinity? Okay. What is it? If I'm if I + + + align:start position:0% +infinity? Okay. What is it? If I'm if I +let's do something easier. What's the + + align:start position:0% +let's do something easier. What's the + + + align:start position:0% +let's do something easier. What's the +input? + + align:start position:0% + + + + align:start position:0% + +Well, it's a unit step, right? So the + + align:start position:0% +Well, it's a unit step, right? So the + + + align:start position:0% +Well, it's a unit step, right? So the +input is some unit step thing, right? So + + align:start position:0% +input is some unit step thing, right? So + + + align:start position:0% +input is some unit step thing, right? So +my input, if I think about some input r + + align:start position:0% +my input, if I think about some input r + + + align:start position:0% +my input, if I think about some input r +of t, the input is something that looks + + align:start position:0% +of t, the input is something that looks + + + align:start position:0% +of t, the input is something that looks +like that, right? So if I look at like + + align:start position:0% +like that, right? So if I look at like + + + align:start position:0% +like that, right? So if I look at like +you suggested, if I look at what's going + + align:start position:0% +you suggested, if I look at what's going + + + align:start position:0% +you suggested, if I look at what's going +to happen for t goes to infinity, what's + + align:start position:0% +to happen for t goes to infinity, what's + + + align:start position:0% +to happen for t goes to infinity, what's +going to happen? Eventually, the rate at + + align:start position:0% +going to happen? Eventually, the rate at + + + align:start position:0% +going to happen? Eventually, the rate at +which water is going out is going to be + + align:start position:0% +which water is going out is going to be + + + align:start position:0% +which water is going out is going to be +the same as the rate that it's going in. + + align:start position:0% +the same as the rate that it's going in. + + + align:start position:0% +the same as the rate that it's going in. +So if + + align:start position:0% +So if + + + align:start position:0% +So if +so based on that, do I like this one, + + align:start position:0% +so based on that, do I like this one, + + + align:start position:0% +so based on that, do I like this one, +this one, this one, this one, or that + + align:start position:0% +this one, this one, this one, or that + + + align:start position:0% +this one, this one, this one, or that +one? + + align:start position:0% + + + + align:start position:0% + +Knocks out one and three because we're + + align:start position:0% +Knocks out one and three because we're + + + align:start position:0% +Knocks out one and three because we're +not expecting it go to zero because the + + align:start position:0% +not expecting it go to zero because the + + + align:start position:0% +not expecting it go to zero because the +input didn't go to zero. Good. Okay. So + + align:start position:0% +input didn't go to zero. Good. Okay. So + + + align:start position:0% +input didn't go to zero. Good. Okay. So +it's maybe this or this or + + align:start position:0% +it's maybe this or this or + + + align:start position:0% +it's maybe this or this or +that. What's a good + + align:start position:0% + + + + align:start position:0% + +method? What's a good method? Yes. So + + align:start position:0% +method? What's a good method? Yes. So + + + align:start position:0% +method? What's a good method? Yes. So +confused me is that the original problem + + align:start position:0% +confused me is that the original problem + + + align:start position:0% +confused me is that the original problem +on the on the problem set we had it was + + align:start position:0% +on the on the problem set we had it was + + + align:start position:0% +on the on the problem set we had it was +a second order system but like this one + + align:start position:0% +a second order system but like this one + + + align:start position:0% +a second order system but like this one +was first order. This is first order. + + align:start position:0% +was first order. This is first order. + + + align:start position:0% +was first order. This is first order. +Yeah. So then you know that it's going + + align:start position:0% +Yeah. So then you know that it's going + + + align:start position:0% +Yeah. So then you know that it's going +to be it's going to look like something + + align:start position:0% +to be it's going to look like something + + + align:start position:0% +to be it's going to look like something +that's first order. Still looks like + + align:start position:0% +that's first order. Still looks like + + + align:start position:0% +that's first order. Still looks like +something that's first order. That's + + align:start position:0% +something that's first order. That's + + + align:start position:0% +something that's first order. That's +good. + + align:start position:0% +good. + + + align:start position:0% +good. +I asked the question here and I flicked + + align:start position:0% +I asked the question here and I flicked + + + align:start position:0% +I asked the question here and I flicked +back here. That was a clue. + + align:start position:0% +back here. That was a clue. + + + align:start position:0% +back here. That was a clue. +How many ways can you think of to do + + align:start position:0% +How many ways can you think of to do + + + align:start position:0% +How many ways can you think of to do +this problem? + + align:start position:0% +this problem? + + + align:start position:0% +this problem? +Five ways. + + align:start position:0% + + + + align:start position:0% + +Okay, you could think about solving it + + align:start position:0% +Okay, you could think about solving it + + + align:start position:0% +Okay, you could think about solving it +by looking at the differential equation. + + align:start position:0% +by looking at the differential equation. + + + align:start position:0% +by looking at the differential equation. +How how many of you could do + + align:start position:0% + + + + align:start position:0% + +that? Okay, how many of you took 1803? + + align:start position:0% +that? Okay, how many of you took 1803? + + + align:start position:0% +that? Okay, how many of you took 1803? +Ah, good. Good. So, all of you could do + + align:start position:0% +Ah, good. Good. So, all of you could do + + + align:start position:0% +Ah, good. Good. So, all of you could do +it by doing the lower lefthand corner, + + align:start position:0% +it by doing the lower lefthand corner, + + + align:start position:0% +it by doing the lower lefthand corner, +right? Okay, you could all do it that + + align:start position:0% +right? Okay, you could all do it that + + + align:start position:0% +right? Okay, you could all do it that +way. Uh, you could all do it with block + + align:start position:0% +way. Uh, you could all do it with block + + + align:start position:0% +way. Uh, you could all do it with block +diagrams, right? I we went around we + + align:start position:0% +diagrams, right? I we went around we + + + align:start position:0% +diagrams, right? I we went around we +thought about how you put a signal into + + align:start position:0% +thought about how you put a signal into + + + align:start position:0% +thought about how you put a signal into +a block diagram and you can chase it + + align:start position:0% +a block diagram and you can chase it + + + align:start position:0% +a block diagram and you can chase it +around the 10, right? You could do it + + align:start position:0% +around the 10, right? You could do it + + + align:start position:0% +around the 10, right? You could do it +that way. You So there's at least five + + align:start position:0% +that way. You So there's at least five + + + align:start position:0% +that way. You So there's at least five +ways. Just as rehearsal, I'm showing two + + align:start position:0% +ways. Just as rehearsal, I'm showing two + + + align:start position:0% +ways. Just as rehearsal, I'm showing two +ways here that don't quite fall there. + + align:start position:0% +ways here that don't quite fall there. + + + align:start position:0% +ways here that don't quite fall there. +So my answer would have been at least + + align:start position:0% +So my answer would have been at least + + + align:start position:0% +So my answer would have been at least +seven ways that I can do this problem + + align:start position:0% +seven ways that I can do this problem + + + align:start position:0% +seven ways that I can do this problem +because I'm going to show you two new + + align:start position:0% +because I'm going to show you two new + + + align:start position:0% +because I'm going to show you two new +ones that don't appear directly. One way + + align:start position:0% +ones that don't appear directly. One way + + + align:start position:0% +ones that don't appear directly. One way +is to think about the diff differential + + align:start position:0% +is to think about the diff differential + + + align:start position:0% +is to think about the diff differential +equation. + + align:start position:0% +equation. + + + align:start position:0% +equation. +Solve it for t less than zero and t + + align:start position:0% +Solve it for t less than zero and t + + + align:start position:0% +Solve it for t less than zero and t +greater than + + align:start position:0% +greater than + + + align:start position:0% +greater than +zero. Paste the solutions + + align:start position:0% + + + + align:start position:0% + +together with me so far. So solver for t + + align:start position:0% +together with me so far. So solver for t + + + align:start position:0% +together with me so far. So solver for t +less than zero. The answer is zero + + align:start position:0% +less than zero. The answer is zero + + + align:start position:0% +less than zero. The answer is zero +because there was no input. Started at + + align:start position:0% +because there was no input. Started at + + + align:start position:0% +because there was no input. Started at +rest. Solver for t bigger than zero. + + align:start position:0% +rest. Solver for t bigger than zero. + + + align:start position:0% +rest. Solver for t bigger than zero. +That means the input is + + align:start position:0% +That means the input is + + + align:start position:0% +That means the input is +one. So you can get some answer for t + + align:start position:0% +one. So you can get some answer for t + + + align:start position:0% +one. So you can get some answer for t +bigger than zero. Paste the two + + align:start position:0% +bigger than zero. Paste the two + + + align:start position:0% +bigger than zero. Paste the two +solutions together by using + + align:start position:0% +solutions together by using + + + align:start position:0% +solutions together by using +um unitstep functions. + + align:start position:0% +um unitstep functions. + + + align:start position:0% +um unitstep functions. +put the total answer back into the der + + align:start position:0% +put the total answer back into the der + + + align:start position:0% +put the total answer back into the der +into the differential + + align:start position:0% +into the differential + + + align:start position:0% +into the differential +equation. That total answer better have + + align:start position:0% +equation. That total answer better have + + + align:start position:0% +equation. That total answer better have +the property that it solves the + + align:start position:0% +the property that it solves the + + + align:start position:0% +the property that it solves the +differential equation for all + + align:start position:0% +differential equation for all + + + align:start position:0% +differential equation for all +time. Okay, nod your head yes. It'll + + align:start position:0% +time. Okay, nod your head yes. It'll + + + align:start position:0% +time. Okay, nod your head yes. It'll +make me feel like you're I'm doing a + + align:start position:0% +make me feel like you're I'm doing a + + + align:start position:0% +make me feel like you're I'm doing a +fantastic job. Right? So, uh and the + + align:start position:0% +fantastic job. Right? So, uh and the + + + align:start position:0% +fantastic job. Right? So, uh and the +only trick there is thinking about how + + align:start position:0% +only trick there is thinking about how + + + align:start position:0% +only trick there is thinking about how +do you do things like differentiate a + + align:start position:0% +do you do things like differentiate a + + + align:start position:0% +do you do things like differentiate a +unitep function. But the derivative of a + + align:start position:0% +unitep function. But the derivative of a + + + align:start position:0% +unitep function. But the derivative of a +unitep function is delta function. + + align:start position:0% +unitep function is delta function. + + + align:start position:0% +unitep function is delta function. +the derivative of one of these things + + align:start position:0% +the derivative of one of these things + + + align:start position:0% +the derivative of one of these things +which looks like a product of something + + align:start position:0% +which looks like a product of something + + + align:start position:0% +which looks like a product of something +that exists for all time and something + + align:start position:0% +that exists for all time and something + + + align:start position:0% +that exists for all time and something +that turns on at zero. It's just the + + align:start position:0% +that turns on at zero. It's just the + + + align:start position:0% +that turns on at zero. It's just the +product rule. Derivative of the first + + align:start position:0% +product rule. Derivative of the first + + + align:start position:0% +product rule. Derivative of the first +times the second plus second times the + + align:start position:0% +times the second plus second times the + + + align:start position:0% +times the second plus second times the +der of the first except I said the same + + align:start position:0% +der of the first except I said the same + + + align:start position:0% +der of the first except I said the same +thing twice. Um + + align:start position:0% +thing twice. Um + + + align:start position:0% +thing twice. Um +okay. And so if you do that you end up + + align:start position:0% +okay. And so if you do that you end up + + + align:start position:0% +okay. And so if you do that you end up +finding out that to match the delta + + align:start position:0% +finding out that to match the delta + + + align:start position:0% +finding out that to match the delta +functions and the u functions it places + + align:start position:0% +functions and the u functions it places + + + align:start position:0% +functions and the u functions it places +additional constraints on the constants. + + align:start position:0% +additional constraints on the constants. + + + align:start position:0% +additional constraints on the constants. +And the answer looks like this. + + align:start position:0% +And the answer looks like this. + + + align:start position:0% +And the answer looks like this. +Okay, everybody sort of sees what I'm + + align:start position:0% +Okay, everybody sort of sees what I'm + + + align:start position:0% +Okay, everybody sort of sees what I'm +saying? Here's a different way you could + + align:start position:0% +saying? Here's a different way you could + + + align:start position:0% +saying? Here's a different way you could +do it. You could think + + align:start position:0% + + + + align:start position:0% + +systems. So on the chart, I told you + + align:start position:0% +systems. So on the chart, I told you + + + align:start position:0% +systems. So on the chart, I told you +what the unit uh impulse response was. + + align:start position:0% +what the unit uh impulse response was. + + + align:start position:0% +what the unit uh impulse response was. +It's one over to E the minus T over to U + + align:start position:0% +It's one over to E the minus T over to U + + + align:start position:0% +It's one over to E the minus T over to U +of TOA U of T. Uh so you could use that + + align:start position:0% +of TOA U of T. Uh so you could use that + + + align:start position:0% +of TOA U of T. Uh so you could use that +to figure out the + + align:start position:0% +to figure out the + + + align:start position:0% +to figure out the +response. If I know that delta goes into + + align:start position:0% +response. If I know that delta goes into + + + align:start position:0% +response. If I know that delta goes into +a system, it gives me the um unit + + align:start position:0% +a system, it gives me the um unit + + + align:start position:0% +a system, it gives me the um unit +impulse response h of + + align:start position:0% +impulse response h of + + + align:start position:0% +impulse response h of +t. And the question then is find the + + align:start position:0% +t. And the question then is find the + + + align:start position:0% +t. And the question then is find the +unitst step response. Well, there's an + + align:start position:0% +unitst step response. Well, there's an + + + align:start position:0% +unitst step response. Well, there's an +easy way to find the unit step. That's + + align:start position:0% +easy way to find the unit step. That's + + + align:start position:0% +easy way to find the unit step. That's +just the integral of the unit + + align:start position:0% + + + + align:start position:0% + +impulse. So apparently the unit step + + align:start position:0% +impulse. So apparently the unit step + + + align:start position:0% +impulse. So apparently the unit step +response of this thing is the same as + + align:start position:0% +response of this thing is the same as + + + align:start position:0% +response of this thing is the same as +the unit impulse response of this + + align:start position:0% +the unit impulse response of this + + + align:start position:0% +the unit impulse response of this +combined system. + + align:start position:0% + + + + align:start position:0% + +But we know from our analysis of systems + + align:start position:0% +But we know from our analysis of systems + + + align:start position:0% +But we know from our analysis of systems +that you're allowed to commute things. + + align:start position:0% +that you're allowed to commute things. + + + align:start position:0% +that you're allowed to commute things. +So that means I can flip this + + align:start position:0% + + + + align:start position:0% + +order. Which means then that all I need + + align:start position:0% +order. Which means then that all I need + + + align:start position:0% +order. Which means then that all I need +to do is integrate the impulse response + + align:start position:0% +to do is integrate the impulse response + + + align:start position:0% +to do is integrate the impulse response +of this thing which I knew by + + align:start position:0% +of this thing which I knew by + + + align:start position:0% +of this thing which I knew by +assumption. So if I integrate the + + align:start position:0% +assumption. So if I integrate the + + + align:start position:0% +assumption. So if I integrate the +impulse response, I get the step + + align:start position:0% +impulse response, I get the step + + + align:start position:0% +impulse response, I get the step +response. That's another way of doing + + align:start position:0% +response. That's another way of doing + + + align:start position:0% +response. That's another way of doing +it. I could do it by lelass transforms. + + align:start position:0% +it. I could do it by lelass transforms. + + + align:start position:0% +it. I could do it by lelass transforms. +I could do it a gazillion ways, right? + + align:start position:0% +I could do it a gazillion ways, right? + + + align:start position:0% +I could do it a gazillion ways, right? +Easy. you should go home and make sure + + align:start position:0% +Easy. you should go home and make sure + + + align:start position:0% +Easy. you should go home and make sure +you can do all of + + align:start position:0% +you can do all of + + + align:start position:0% +you can do all of +those. Okay, so the answer then was + + align:start position:0% +those. Okay, so the answer then was + + + align:start position:0% +those. Okay, so the answer then was +number two. It's this thing. It's the + + align:start position:0% +number two. It's this thing. It's the + + + align:start position:0% +number two. It's this thing. It's the +first order response. Like was said, it + + align:start position:0% +first order response. Like was said, it + + + align:start position:0% +first order response. Like was said, it +has to go to a particular final value + + align:start position:0% +has to go to a particular final value + + + align:start position:0% +has to go to a particular final value +which is equal to the um uh final value + + align:start position:0% +which is equal to the um uh final value + + + align:start position:0% +which is equal to the um uh final value +of the input. There's a there's a + + align:start position:0% +of the input. There's a there's a + + + align:start position:0% +of the input. There's a there's a +variety of ways you could get that. + + align:start position:0% +variety of ways you could get that. + + + align:start position:0% +variety of ways you could get that. +Okay, the point of today then is to take + + align:start position:0% +Okay, the point of today then is to take + + + align:start position:0% +Okay, the point of today then is to take +that unit sample response that unit + + align:start position:0% +that unit sample response that unit + + + align:start position:0% +that unit sample response that unit +response and figure out ways to + + align:start position:0% +response and figure out ways to + + + align:start position:0% +response and figure out ways to +approximate it. What I want to do is + + align:start position:0% +approximate it. What I want to do is + + + align:start position:0% +approximate it. What I want to do is +think about how I would make a discrete + + align:start position:0% +think about how I would make a discrete + + + align:start position:0% +think about how I would make a discrete +representation for the CT system, the + + align:start position:0% +representation for the CT system, the + + + align:start position:0% +representation for the CT system, the +leaky tank + + align:start position:0% +leaky tank + + + align:start position:0% +leaky tank +system. You've done this in homework. + + align:start position:0% +system. You've done this in homework. + + + align:start position:0% +system. You've done this in homework. +This was homework + + align:start position:0% +This was homework + + + align:start position:0% +This was homework +one. What I'm trying to do is get some + + align:start position:0% +one. What I'm trying to do is get some + + + align:start position:0% +one. What I'm trying to do is get some +new perspective by thinking about all + + align:start position:0% +new perspective by thinking about all + + + align:start position:0% +new perspective by thinking about all +those representations that we have on + + align:start position:0% +those representations that we have on + + + align:start position:0% +those representations that we have on +the answer that you already derived in + + align:start position:0% +the answer that you already derived in + + + align:start position:0% +the answer that you already derived in +homework one. + + align:start position:0% +homework one. + + + align:start position:0% +homework one. +So if I wanted to represent this system, + + align:start position:0% +So if I wanted to represent this system, + + + align:start position:0% +So if I wanted to represent this system, +the leaky tank system by a difference + + align:start position:0% +the leaky tank system by a difference + + + align:start position:0% +the leaky tank system by a difference +equation, one way to get the difference + + align:start position:0% +equation, one way to get the difference + + + align:start position:0% +equation, one way to get the difference +equation is to make an approximation to + + align:start position:0% +equation is to make an approximation to + + + align:start position:0% +equation is to make an approximation to +the + + align:start position:0% +the + + + align:start position:0% +the +derivative based on + + align:start position:0% +derivative based on + + + align:start position:0% +derivative based on +differences. The easiest way to do that + + align:start position:0% +differences. The easiest way to do that + + + align:start position:0% +differences. The easiest way to do that +is something that we will call the + + align:start position:0% +is something that we will call the + + + align:start position:0% +is something that we will call the +forward oiler + + align:start position:0% +forward oiler + + + align:start position:0% +forward oiler +method. Uh in the forward oiler method, + + align:start position:0% +method. Uh in the forward oiler method, + + + align:start position:0% +method. Uh in the forward oiler method, +what we do is we think about all the + + align:start position:0% +what we do is we think about all the + + + align:start position:0% +what we do is we think about all the +functions of time. Say we have an x + + align:start position:0% +functions of time. Say we have an x + + + align:start position:0% +functions of time. Say we have an x +function of time and a y function of + + align:start position:0% +function of time and a y function of + + + align:start position:0% +function of time and a y function of +time, the input and the output. + + align:start position:0% +time, the input and the output. + + + align:start position:0% +time, the input and the output. +I've got the continuous version and the + + align:start position:0% +I've got the continuous version and the + + + align:start position:0% +I've got the continuous version and the +discrete version. That's the sub C and + + align:start position:0% +discrete version. That's the sub C and + + + align:start position:0% +discrete version. That's the sub C and +the sub + + align:start position:0% +the sub + + + align:start position:0% +the sub +D. The way I could make an association + + align:start position:0% +D. The way I could make an association + + + align:start position:0% +D. The way I could make an association +between discrete and continuous is by + + align:start position:0% +between discrete and continuous is by + + + align:start position:0% +between discrete and continuous is by +sampling the + + align:start position:0% +sampling the + + + align:start position:0% +sampling the +signals. So I could say that if I knew X + + align:start position:0% +signals. So I could say that if I knew X + + + align:start position:0% +signals. So I could say that if I knew X +subC of T, that's going to be some + + align:start position:0% +subC of T, that's going to be some + + + align:start position:0% +subC of T, that's going to be some +squirrely function. But I don't know the + + align:start position:0% +squirrely function. But I don't know the + + + align:start position:0% +squirrely function. But I don't know the +answer. I don't know what that is. But + + align:start position:0% +answer. I don't know what that is. But + + + align:start position:0% +answer. I don't know what that is. But +whatever it is, I will say that the + + align:start position:0% +whatever it is, I will say that the + + + align:start position:0% +whatever it is, I will say that the +discrete version at time + + align:start position:0% +discrete version at time + + + align:start position:0% +discrete version at time +n is the same as the continuous version + + align:start position:0% +n is the same as the continuous version + + + align:start position:0% +n is the same as the continuous version +at time n * t. t is a sampling + + align:start position:0% +at time n * t. t is a sampling + + + align:start position:0% +at time n * t. t is a sampling +interval. And the discrete version of + + align:start position:0% +interval. And the discrete version of + + + align:start position:0% +interval. And the discrete version of +this uh y function, this output function + + align:start position:0% +this uh y function, this output function + + + align:start position:0% +this uh y function, this output function +at time n +1 t is the n+1 + + align:start position:0% +at time n +1 t is the n+1 + + + align:start position:0% +at time n +1 t is the n+1 +sample of the discretetized output + + align:start position:0% +sample of the discretetized output + + + align:start position:0% +sample of the discretetized output +signal. Then the trick to to um solving + + align:start position:0% +signal. Then the trick to to um solving + + + align:start position:0% +signal. Then the trick to to um solving +the differential equation remember the + + align:start position:0% +the differential equation remember the + + + align:start position:0% +the differential equation remember the +differential equation looked like + + align:start position:0% +differential equation looked like + + + align:start position:0% +differential equation looked like +to y dot of t is x of t uh minus y of t. + + align:start position:0% +to y dot of t is x of t uh minus y of t. + + + align:start position:0% +to y dot of t is x of t uh minus y of t. +I need to have a way of thinking about + + align:start position:0% +I need to have a way of thinking about + + + align:start position:0% +I need to have a way of thinking about +this y dot + + align:start position:0% +this y dot + + + align:start position:0% +this y dot +thing. A way of thinking about the y dot + + align:start position:0% +thing. A way of thinking about the y dot + + + align:start position:0% +thing. A way of thinking about the y dot +thing would be the slope of the line + + align:start position:0% +thing would be the slope of the line + + + align:start position:0% +thing would be the slope of the line +that connects this sample to the next + + align:start position:0% +that connects this sample to the next + + + align:start position:0% +that connects this sample to the next +sample. We call it forward order because + + align:start position:0% +sample. We call it forward order because + + + align:start position:0% +sample. We call it forward order because +at time n we we approximate the + + align:start position:0% +at time n we we approximate the + + + align:start position:0% +at time n we we approximate the +derivative at time n by looking + + align:start position:0% +derivative at time n by looking + + + align:start position:0% +derivative at time n by looking +forward. So we approximate the + + align:start position:0% +forward. So we approximate the + + + align:start position:0% +forward. So we approximate the +derivative of y continuous at time nt by + + align:start position:0% +derivative of y continuous at time nt by + + + align:start position:0% +derivative of y continuous at time nt by +looking forward. yd of n +1 minus yd of + + align:start position:0% +looking forward. yd of n +1 minus yd of + + + align:start position:0% +looking forward. yd of n +1 minus yd of +n + + align:start position:0% +n + + + align:start position:0% +n +/t. Then all we need to do is make that + + align:start position:0% +/t. Then all we need to do is make that + + + align:start position:0% +/t. Then all we need to do is make that +substitution into the differential + + align:start position:0% +substitution into the differential + + + align:start position:0% +substitution into the differential +equation. + + align:start position:0% +equation. + + + align:start position:0% +equation. +and it turns it into a difference + + align:start position:0% +and it turns it into a difference + + + align:start position:0% +and it turns it into a difference +equation. So if I make the substitution + + align:start position:0% +equation. So if I make the substitution + + + align:start position:0% +equation. So if I make the substitution +that y dot is given by this kind of an + + align:start position:0% +that y dot is given by this kind of an + + + align:start position:0% +that y dot is given by this kind of an +expression substitute into this + + align:start position:0% +expression substitute into this + + + align:start position:0% +expression substitute into this +expression I get a difference equation + + align:start position:0% +expression I get a difference equation + + + align:start position:0% +expression I get a difference equation +that is in some sense equivalent to the + + align:start position:0% +that is in some sense equivalent to the + + + align:start position:0% +that is in some sense equivalent to the +original differential + + align:start position:0% +original differential + + + align:start position:0% +original differential +equation. I can solve that difference + + align:start position:0% +equation. I can solve that difference + + + align:start position:0% +equation. I can solve that difference +equation and I get that bottom + + align:start position:0% +equation and I get that bottom + + + align:start position:0% +equation and I get that bottom +difference + + align:start position:0% +difference + + + align:start position:0% +difference +relationship. That's what you did in + + align:start position:0% +relationship. That's what you did in + + + align:start position:0% +relationship. That's what you did in +homework one. If you were to plot that + + align:start position:0% +homework one. If you were to plot that + + + align:start position:0% +homework one. If you were to plot that +answer, here's what you would + + align:start position:0% + + + + align:start position:0% + +get. The blue curve represents the + + align:start position:0% +get. The blue curve represents the + + + align:start position:0% +get. The blue curve represents the +continuous the solution to the leaky + + align:start position:0% +continuous the solution to the leaky + + + align:start position:0% +continuous the solution to the leaky +tank problem. The continuous problem 1 + + align:start position:0% +tank problem. The continuous problem 1 + + + align:start position:0% +tank problem. The continuous problem 1 +minus e to the minus t over towo + + align:start position:0% +minus e to the minus t over towo + + + align:start position:0% +minus e to the minus t over towo +quantity u of t. So that's the blue + + align:start position:0% +quantity u of t. So that's the blue + + + align:start position:0% +quantity u of t. So that's the blue +line. If you select the sampling + + align:start position:0% +line. If you select the sampling + + + align:start position:0% +line. If you select the sampling +interval to be small compared to tao, + + align:start position:0% +interval to be small compared to tao, + + + align:start position:0% +interval to be small compared to tao, +tao was the time constant for the CT + + align:start position:0% +tao was the time constant for the CT + + + align:start position:0% +tao was the time constant for the CT +system. If you select the sampling + + align:start position:0% +system. If you select the sampling + + + align:start position:0% +system. If you select the sampling +interval to be small 0.1, the samples + + align:start position:0% +interval to be small 0.1, the samples + + + align:start position:0% +interval to be small 0.1, the samples +that you calculate fall right on top of + + align:start position:0% +that you calculate fall right on top of + + + align:start position:0% +that you calculate fall right on top of +the line. + + align:start position:0% +the line. + + + align:start position:0% +the line. +Great. That's what we would want, right? + + align:start position:0% +Great. That's what we would want, right? + + + align:start position:0% +Great. That's what we would want, right? +We're trying to make a dt approximation. + + align:start position:0% +We're trying to make a dt approximation. + + + align:start position:0% +We're trying to make a dt approximation. +If the approximation work, the solution + + align:start position:0% +If the approximation work, the solution + + + align:start position:0% +If the approximation work, the solution +to the dt equations should be the same + + align:start position:0% +to the dt equations should be the same + + + align:start position:0% +to the dt equations should be the same +in some sense as the solution to the ct + + align:start position:0% +in some sense as the solution to the ct + + + align:start position:0% +in some sense as the solution to the ct +equations. + + align:start position:0% + + + + align:start position:0% + +But if you change capital t, you get + + align:start position:0% +But if you change capital t, you get + + + align:start position:0% +But if you change capital t, you get +something that looks decreasingly like + + align:start position:0% +something that looks decreasingly like + + + align:start position:0% +something that looks decreasingly like +the continuous version. If you make t uh + + align:start position:0% +the continuous version. If you make t uh + + + align:start position:0% +the continuous version. If you make t uh +step bigger and bigger per per time, t + + align:start position:0% +step bigger and bigger per per time, t + + + align:start position:0% +step bigger and bigger per per time, t +is the sampling interval. If I started + + align:start position:0% +is the sampling interval. If I started + + + align:start position:0% +is the sampling interval. If I started +with a small sampling interval, I got a + + align:start position:0% +with a small sampling interval, I got a + + + align:start position:0% +with a small sampling interval, I got a +good approximation. By the time I get + + align:start position:0% +good approximation. By the time I get + + + align:start position:0% +good approximation. By the time I get +the sampling interval up to 2T, it the + + align:start position:0% +the sampling interval up to 2T, it the + + + align:start position:0% +the sampling interval up to 2T, it the +solution to the DT problem looks nothing + + align:start position:0% +solution to the DT problem looks nothing + + + align:start position:0% +solution to the DT problem looks nothing +like the solution to the CT + + align:start position:0% +like the solution to the CT + + + align:start position:0% +like the solution to the CT +problem. Okay, that's a general problem + + align:start position:0% +problem. Okay, that's a general problem + + + align:start position:0% +problem. Okay, that's a general problem +in a numerical method. So, what we're + + align:start position:0% +in a numerical method. So, what we're + + + align:start position:0% +in a numerical method. So, what we're +really talking about is analysis of + + align:start position:0% +really talking about is analysis of + + + align:start position:0% +really talking about is analysis of +numerical methods. What went + + align:start position:0% +numerical methods. What went + + + align:start position:0% +numerical methods. What went +wrong? Why is it that the approximation + + align:start position:0% +wrong? Why is it that the approximation + + + align:start position:0% +wrong? Why is it that the approximation +worked well and didn't work well? I + + align:start position:0% +worked well and didn't work well? I + + + align:start position:0% +worked well and didn't work well? I +mean, it's intuitively clear that that's + + align:start position:0% +mean, it's intuitively clear that that's + + + align:start position:0% +mean, it's intuitively clear that that's +what you should have done, but we'd like + + align:start position:0% +what you should have done, but we'd like + + + align:start position:0% +what you should have done, but we'd like +to be a little more formal and we'd like + + align:start position:0% +to be a little more formal and we'd like + + + align:start position:0% +to be a little more formal and we'd like +to be a little more quantitative. What + + align:start position:0% +to be a little more quantitative. What + + + align:start position:0% +to be a little more quantitative. What +was it that went + + align:start position:0% +was it that went + + + align:start position:0% +was it that went +wrong? So, to get some insight, let's + + align:start position:0% +wrong? So, to get some insight, let's + + + align:start position:0% +wrong? So, to get some insight, let's +figure out the pole for the DT system. + + align:start position:0% +figure out the pole for the DT system. + + + align:start position:0% +figure out the pole for the DT system. +Where's the pole? + + align:start position:0% + + + + align:start position:0% + +Okay. Where's the pole? Where's the pole + + align:start position:0% +Okay. Where's the pole? Where's the pole + + + align:start position:0% +Okay. Where's the pole? Where's the pole +of the DT + + align:start position:0% + + + + align:start position:0% + +system? Okay. not a large voter turnout + + align:start position:0% +system? Okay. not a large voter turnout + + + align:start position:0% +system? Okay. not a large voter turnout +but 100% among those who turned out. So + + align:start position:0% +but 100% among those who turned out. So + + + align:start position:0% +but 100% among those who turned out. So +the answer is uh number two. It's pretty + + align:start position:0% +the answer is uh number two. It's pretty + + + align:start position:0% +the answer is uh number two. It's pretty +simple to see how that would be the + + align:start position:0% +simple to see how that would be the + + + align:start position:0% +simple to see how that would be the +answer. If you start with the difference + + align:start position:0% +answer. If you start with the difference + + + align:start position:0% +answer. If you start with the difference +equation, it's very simple to write a z + + align:start position:0% +equation, it's very simple to write a z + + + align:start position:0% +equation, it's very simple to write a z +transform. This evaluate y at n + one is + + align:start position:0% +transform. This evaluate y at n + one is + + + align:start position:0% +transform. This evaluate y at n + one is +the reverse of a delay. It's an advance. + + align:start position:0% +the reverse of a delay. It's an advance. + + + align:start position:0% +the reverse of a delay. It's an advance. +Delay is multiplied by z minus one. So + + align:start position:0% +Delay is multiplied by z minus one. So + + + align:start position:0% +Delay is multiplied by z minus one. So +advanced is multiply by + + align:start position:0% +advanced is multiply by + + + align:start position:0% +advanced is multiply by +Z. So you can take the Z transform of + + align:start position:0% +Z. So you can take the Z transform of + + + align:start position:0% +Z. So you can take the Z transform of +the difference equation to to derive the + + align:start position:0% +the difference equation to to derive the + + + align:start position:0% +the difference equation to to derive the +Z + + align:start position:0% +Z + + + align:start position:0% +Z +transform of the system + + align:start position:0% + + + + align:start position:0% + +function. And then clearly there's a + + align:start position:0% +function. And then clearly there's a + + + align:start position:0% +function. And then clearly there's a +pole here at Z = 1 - T over + + align:start position:0% +pole here at Z = 1 - T over + + + align:start position:0% +pole here at Z = 1 - T over +to so the answer was number two. And it + + align:start position:0% +to so the answer was number two. And it + + + align:start position:0% +to so the answer was number two. And it +gives us a way to think + + align:start position:0% +gives us a way to think + + + align:start position:0% +gives us a way to think +about why the difference + + align:start position:0% +about why the difference + + + align:start position:0% +about why the difference +solution didn't work. Well, what we can + + align:start position:0% +solution didn't work. Well, what we can + + + align:start position:0% +solution didn't work. Well, what we can +see is that even though you remember the + + align:start position:0% +see is that even though you remember the + + + align:start position:0% +see is that even though you remember the +the um what was the pole of the CT + + align:start position:0% + + + + align:start position:0% + +system? What's the pole of the CT + + align:start position:0% +system? What's the pole of the CT + + + align:start position:0% +system? What's the pole of the CT +system? + + align:start position:0% + + + + align:start position:0% + +How do you think about the pole of a CT + + align:start position:0% + + + + align:start position:0% + +system? Close. What's the pole of the CT + + align:start position:0% + + + + align:start position:0% + +system? Minus one over towal. So we + + align:start position:0% +system? Minus one over towal. So we + + + align:start position:0% +system? Minus one over towal. So we +would do the same sort of thing but now + + align:start position:0% +would do the same sort of thing but now + + + align:start position:0% +would do the same sort of thing but now +with with a lelass transform, right? + + align:start position:0% +with with a lelass transform, right? + + + align:start position:0% +with with a lelass transform, right? +So we would say that we could write the + + align:start position:0% +So we would say that we could write the + + + align:start position:0% +So we would say that we could write the +applause transform of this. This would + + align:start position:0% +applause transform of this. This would + + + align:start position:0% +applause transform of this. This would +be s to + + align:start position:0% +be s to + + + align:start position:0% +be s to +y is x minus + + align:start position:0% +y is x minus + + + align:start position:0% +y is x minus +y. And the uh pole is going to end up + + align:start position:0% +y. And the uh pole is going to end up + + + align:start position:0% +y. And the uh pole is going to end up +with the pole that we get in the s plane + + align:start position:0% +with the pole that we get in the s plane + + + align:start position:0% +with the pole that we get in the s plane +is going to be 1 over 1 + + align:start position:0% +is going to be 1 over 1 + + + align:start position:0% +is going to be 1 over 1 +- 1 over + + align:start position:0% +- 1 over + + + align:start position:0% +- 1 over +to despite the fact that the pole in the + + align:start position:0% +to despite the fact that the pole in the + + + align:start position:0% +to despite the fact that the pole in the +s + + align:start position:0% +s + + + align:start position:0% +s +plane was the same for all the + + align:start position:0% +plane was the same for all the + + + align:start position:0% +plane was the same for all the +simulations. The simulations the + + align:start position:0% +simulations. The simulations the + + + align:start position:0% +simulations. The simulations the +discrete versions look different. And + + align:start position:0% +discrete versions look different. And + + + align:start position:0% +discrete versions look different. And +that's because the pole for the DT + + align:start position:0% +that's because the pole for the DT + + + align:start position:0% +that's because the pole for the DT +system is not the same. The pole for the + + align:start position:0% +system is not the same. The pole for the + + + align:start position:0% +system is not the same. The pole for the +DT system depended both on tow as did + + align:start position:0% +DT system depended both on tow as did + + + align:start position:0% +DT system depended both on tow as did +the pole for the CT + + align:start position:0% +the pole for the CT + + + align:start position:0% +the pole for the CT +system. But the DCT the DT system the + + align:start position:0% +system. But the DCT the DT system the + + + align:start position:0% +system. But the DCT the DT system the +pole depended also on capital + + align:start position:0% + + + + align:start position:0% + +T. Right? So we said that the pole you + + align:start position:0% +T. Right? So we said that the pole you + + + align:start position:0% +T. Right? So we said that the pole you +remember the solution to the last + + align:start position:0% +remember the solution to the last + + + align:start position:0% +remember the solution to the last +problem the pole was at 1 minus t over + + align:start position:0% +problem the pole was at 1 minus t over + + + align:start position:0% +problem the pole was at 1 minus t over +tow. So if t over tow is 0.1 the pole is + + align:start position:0% +tow. So if t over tow is 0.1 the pole is + + + align:start position:0% +tow. So if t over tow is 0.1 the pole is +at + + align:start position:0% +at + + + align:start position:0% +at +0.9. If t over tow is 3 the pole is at + + align:start position:0% +0.9. If t over tow is 3 the pole is at + + + align:start position:0% +0.9. If t over tow is 3 the pole is at +7. If the pole is at 2 it's 1 - 2 is + + align:start position:0% +7. If the pole is at 2 it's 1 - 2 is + + + align:start position:0% +7. If the pole is at 2 it's 1 - 2 is +minus1. + + align:start position:0% +minus1. + + + align:start position:0% +minus1. +So the pole for the dt system depends on + + align:start position:0% +So the pole for the dt system depends on + + + align:start position:0% +So the pole for the dt system depends on +both t and + + align:start position:0% +both t and + + + align:start position:0% +both t and +toao and it's given formally by by this + + align:start position:0% +toao and it's given formally by by this + + + align:start position:0% +toao and it's given formally by by this +relationship that + + align:start position:0% +relationship that + + + align:start position:0% +relationship that +z the equivalent pole in the dt system + + align:start position:0% +z the equivalent pole in the dt system + + + align:start position:0% +z the equivalent pole in the dt system +is 1 minus t over + + align:start position:0% +is 1 minus t over + + + align:start position:0% +is 1 minus t over +tow. So the pole in the CT system was um + + align:start position:0% +tow. So the pole in the CT system was um + + + align:start position:0% +tow. So the pole in the CT system was um +minus one over to the pole in the dt + + align:start position:0% +minus one over to the pole in the dt + + + align:start position:0% +minus one over to the pole in the dt +system + + align:start position:0% + + + + align:start position:0% + +moved. The amazing + + align:start position:0% +moved. The amazing + + + align:start position:0% +moved. The amazing +thing is that the correspondence between + + align:start position:0% +thing is that the correspondence between + + + align:start position:0% +thing is that the correspondence between +where the pole in the CT system + + align:start position:0% +where the pole in the CT system + + + align:start position:0% +where the pole in the CT system +was and where the pole in the DT system + + align:start position:0% +was and where the pole in the DT system + + + align:start position:0% +was and where the pole in the DT system +is is completely determined by the + + align:start position:0% +is is completely determined by the + + + align:start position:0% +is is completely determined by the +forward oiler method. It has nothing to + + align:start position:0% +forward oiler method. It has nothing to + + + align:start position:0% +forward oiler method. It has nothing to +do with the particular + + align:start position:0% + + + + align:start position:0% + +problem. Okay. So we just did we just + + align:start position:0% +problem. Okay. So we just did we just + + + align:start position:0% +problem. Okay. So we just did we just +figured out the map between the pole in + + align:start position:0% +figured out the map between the pole in + + + align:start position:0% +figured out the map between the pole in +the S domain and the pole in the Z + + align:start position:0% +the S domain and the pole in the Z + + + align:start position:0% +the S domain and the pole in the Z +domain for a particular problem for the + + align:start position:0% +domain for a particular problem for the + + + align:start position:0% +domain for a particular problem for the +leaky tank. It turns out that that same + + align:start position:0% +leaky tank. It turns out that that same + + + align:start position:0% +leaky tank. It turns out that that same +map holds for every differential + + align:start position:0% +map holds for every differential + + + align:start position:0% +map holds for every differential +equation. So what I want to think about + + align:start position:0% +equation. So what I want to think about + + + align:start position:0% +equation. So what I want to think about +now is how you would prove such a + + align:start position:0% +now is how you would prove such a + + + align:start position:0% +now is how you would prove such a +statement. + + align:start position:0% + + + + align:start position:0% + +So think about regardless of the CT + + align:start position:0% +So think about regardless of the CT + + + align:start position:0% +So think about regardless of the CT +system that we're thinking + + align:start position:0% +system that we're thinking + + + align:start position:0% +system that we're thinking +about I can always write it in a block + + align:start position:0% +about I can always write it in a block + + + align:start position:0% +about I can always write it in a block +diagram form with adders integrators + + align:start position:0% +diagram form with adders integrators + + + align:start position:0% +diagram form with adders integrators +u is it adders integrators and + + align:start position:0% +u is it adders integrators and + + + align:start position:0% +u is it adders integrators and +gains so for the leaky tank system that + + align:start position:0% +gains so for the leaky tank system that + + + align:start position:0% +gains so for the leaky tank system that +was easy I my system looked like um + + align:start position:0% +was easy I my system looked like um + + + align:start position:0% +was easy I my system looked like um +let's see I had one over towo + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% + + + + align:start position:0% + +integrate + + align:start position:0% +integrate + + + align:start position:0% +integrate +add. So my system for the leaky tank + + align:start position:0% +add. So my system for the leaky tank + + + align:start position:0% +add. So my system for the leaky tank +system looked like + + align:start position:0% + + + + align:start position:0% + +that. So the point is that there's an a + + align:start position:0% +that. So the point is that there's an a + + + align:start position:0% +that. So the point is that there's an a +there. The oiler forward relationship is + + align:start position:0% +there. The oiler forward relationship is + + + align:start position:0% +there. The oiler forward relationship is +telling me how I can figure + + align:start position:0% +telling me how I can figure + + + align:start position:0% +telling me how I can figure +out a dt representation for the a + + align:start position:0% +out a dt representation for the a + + + align:start position:0% +out a dt representation for the a +function. So let's think about what a + + align:start position:0% +function. So let's think about what a + + + align:start position:0% +function. So let's think about what a +is. a a is a thing that in + + align:start position:0% + + + + align:start position:0% + +ct. If the output of a is y, what's the + + align:start position:0% +ct. If the output of a is y, what's the + + + align:start position:0% +ct. If the output of a is y, what's the +input to a? + + align:start position:0% + + + + align:start position:0% + +The derivative. It's the derivative. So + + align:start position:0% +The derivative. It's the derivative. So + + + align:start position:0% +The derivative. It's the derivative. So +the input we would want to call y + + align:start position:0% +the input we would want to call y + + + align:start position:0% +the input we would want to call y +dot. So I might say that's + + align:start position:0% +dot. So I might say that's + + + align:start position:0% +dot. So I might say that's +x. So if the input is x, which is y dot, + + align:start position:0% +x. So if the input is x, which is y dot, + + + align:start position:0% +x. So if the input is x, which is y dot, +I put it through an a box and it comes + + align:start position:0% +I put it through an a box and it comes + + + align:start position:0% +I put it through an a box and it comes +out + + align:start position:0% +out + + + align:start position:0% +out +y. So what's the oiler forward rule + + align:start position:0% +y. So what's the oiler forward rule + + + align:start position:0% +y. So what's the oiler forward rule +say? So the oiler forward rule says that + + align:start position:0% +say? So the oiler forward rule says that + + + align:start position:0% +say? So the oiler forward rule says that +if I want to compute x of n, the nth + + align:start position:0% +if I want to compute x of n, the nth + + + align:start position:0% +if I want to compute x of n, the nth +sample of this thing, I should do y dot. + + align:start position:0% +sample of this thing, I should do y dot. + + + align:start position:0% +sample of this thing, I should do y dot. +But y dot I'm doing oiler forward. But I + + align:start position:0% +But y dot I'm doing oiler forward. But I + + + align:start position:0% +But y dot I'm doing oiler forward. But I +should look + + align:start position:0% +should look + + + align:start position:0% +should look +ahead. So I should compute y dot as y of + + align:start position:0% +ahead. So I should compute y dot as y of + + + align:start position:0% +ahead. So I should compute y dot as y of +n + 1 - y of n / + + align:start position:0% + + + + align:start position:0% + +t. + + align:start position:0% +t. + + + align:start position:0% +t. +Okay. Now if I want to make a dt + + align:start position:0% +Okay. Now if I want to make a dt + + + align:start position:0% +Okay. Now if I want to make a dt +equivalent system, what I'd like to have + + align:start position:0% +equivalent system, what I'd like to have + + + align:start position:0% +equivalent system, what I'd like to have +is some kind of a box that I could put x + + align:start position:0% +is some kind of a box that I could put x + + + align:start position:0% +is some kind of a box that I could put x +of n in and get y of n out. + + align:start position:0% +of n in and get y of n out. + + + align:start position:0% +of n in and get y of n out. +If I had such a + + align:start position:0% +If I had such a + + + align:start position:0% +If I had such a +box, then I could replace every A in my + + align:start position:0% +box, then I could replace every A in my + + + align:start position:0% +box, then I could replace every A in my +CT block diagram with this new box that + + align:start position:0% +CT block diagram with this new box that + + + align:start position:0% +CT block diagram with this new box that +depends only on + + align:start position:0% +depends only on + + + align:start position:0% +depends only on +delays. So let's think about what would + + align:start position:0% +delays. So let's think about what would + + + align:start position:0% +delays. So let's think about what would +be in that box. If I wanted to make y of + + align:start position:0% +be in that box. If I wanted to make y of + + + align:start position:0% +be in that box. If I wanted to make y of +n out of x of n according to this rule, + + align:start position:0% +n out of x of n according to this rule, + + + align:start position:0% +n out of x of n according to this rule, +what would I + + align:start position:0% +what would I + + + align:start position:0% +what would I +do? Well, let's see. y of n + + + align:start position:0% +do? Well, let's see. y of n + + + + align:start position:0% +do? Well, let's see. y of n + +1 should be y of + + align:start position:0% +1 should be y of + + + align:start position:0% +1 should be y of +n added to tx of + + align:start position:0% + + + + align:start position:0% + +n. So if I want to compute y of n + 1, + + align:start position:0% +n. So if I want to compute y of n + 1, + + + align:start position:0% +n. So if I want to compute y of n + 1, +oh dear, what's y of n plus one? Where's + + align:start position:0% +oh dear, what's y of n plus one? Where's + + + align:start position:0% +oh dear, what's y of n plus one? Where's +how do I generate my my output? I want + + align:start position:0% +how do I generate my my output? I want + + + align:start position:0% +how do I generate my my output? I want +to be y I want to be y of n. Where's y + + align:start position:0% +to be y I want to be y of n. Where's y + + + align:start position:0% +to be y I want to be y of n. Where's y +of n plus one? + + align:start position:0% +of n plus one? + + + align:start position:0% +of n plus one? +If I knew y of n, how would I compute y + + align:start position:0% +If I knew y of n, how would I compute y + + + align:start position:0% +If I knew y of n, how would I compute y +of n plus one? + + align:start position:0% + + + + align:start position:0% + +It would be back one. + + align:start position:0% +It would be back one. + + + align:start position:0% +It would be back one. +So if I had an r + + align:start position:0% +So if I had an r + + + align:start position:0% +So if I had an r +here, what would be the name of this + + align:start position:0% +here, what would be the name of this + + + align:start position:0% +here, what would be the name of this +guy? This would be y of n plus one, + + align:start position:0% +guy? This would be y of n plus one, + + + align:start position:0% +guy? This would be y of n plus one, +right? Delays have the property that + + align:start position:0% +right? Delays have the property that + + + align:start position:0% +right? Delays have the property that +their output is minus + + align:start position:0% +their output is minus + + + align:start position:0% +their output is minus +one. I need a signal that's plus one. So + + align:start position:0% +one. I need a signal that's plus one. So + + + align:start position:0% +one. I need a signal that's plus one. So +I need the reverse of a delay. + + align:start position:0% +I need the reverse of a delay. + + + align:start position:0% +I need the reverse of a delay. +which I can implement by having this y + + align:start position:0% +which I can implement by having this y + + + align:start position:0% +which I can implement by having this y +signal being generated by an + + align:start position:0% +signal being generated by an + + + align:start position:0% +signal being generated by an +r. Then this equation says that in order + + align:start position:0% +r. Then this equation says that in order + + + align:start position:0% +r. Then this equation says that in order +to compute y of n plus1 this thing, what + + align:start position:0% +to compute y of n plus1 this thing, what + + + align:start position:0% +to compute y of n plus1 this thing, what +I need to do is add this to + + align:start position:0% +I need to do is add this to + + + align:start position:0% +I need to do is add this to +that. So I need to + + align:start position:0% +that. So I need to + + + align:start position:0% +that. So I need to +add + + align:start position:0% +add + + + align:start position:0% +add +this + + align:start position:0% +this + + + align:start position:0% +this +to that. + + align:start position:0% + + + + align:start position:0% + +Okay, the oiler forward rule says if I + + align:start position:0% +Okay, the oiler forward rule says if I + + + align:start position:0% +Okay, the oiler forward rule says if I +want to make a discrete approximation to + + align:start position:0% +want to make a discrete approximation to + + + align:start position:0% +want to make a discrete approximation to +the relationship between y at the output + + align:start position:0% +the relationship between y at the output + + + align:start position:0% +the relationship between y at the output +and its derivative at the input, I + + align:start position:0% +and its derivative at the input, I + + + align:start position:0% +and its derivative at the input, I +should do make one of those + + align:start position:0% +should do make one of those + + + align:start position:0% +should do make one of those +boxes. Okay, I have a rule now. + + align:start position:0% +boxes. Okay, I have a rule now. + + + align:start position:0% +boxes. Okay, I have a rule now. +Regardless of my CT + + align:start position:0% +Regardless of my CT + + + align:start position:0% +Regardless of my CT +system, I'll take every integrator and + + align:start position:0% +system, I'll take every integrator and + + + align:start position:0% +system, I'll take every integrator and +stick one of those in + + align:start position:0% +stick one of those in + + + align:start position:0% +stick one of those in +it. And what I'll have is a DT + + align:start position:0% +it. And what I'll have is a DT + + + align:start position:0% +it. And what I'll have is a DT +approximation to my CT system. that's + + align:start position:0% +approximation to my CT system. that's + + + align:start position:0% +approximation to my CT system. that's +everywhere based on the oiler forward + + align:start position:0% +everywhere based on the oiler forward + + + align:start position:0% +everywhere based on the oiler forward +rule. Is that + + align:start position:0% +rule. Is that + + + align:start position:0% +rule. Is that +clear? So now I have a rule for + + align:start position:0% +clear? So now I have a rule for + + + align:start position:0% +clear? So now I have a rule for +converting an arbitrary CT system into + + align:start position:0% +converting an arbitrary CT system into + + + align:start position:0% +converting an arbitrary CT system into +an equivalent DT system. Equivalent in + + align:start position:0% +an equivalent DT system. Equivalent in + + + align:start position:0% +an equivalent DT system. Equivalent in +the sense of oiler + + align:start position:0% +the sense of oiler + + + align:start position:0% +the sense of oiler +forward and I know that that + + align:start position:0% +forward and I know that that + + + align:start position:0% +forward and I know that that +transformation will hold. But it's even + + align:start position:0% +transformation will hold. But it's even + + + align:start position:0% +transformation will hold. But it's even +better than + + align:start position:0% +better than + + + align:start position:0% +better than +that because I can now say something + + align:start position:0% +that because I can now say something + + + align:start position:0% +that because I can now say something +about the relationship between the + + align:start position:0% +about the relationship between the + + + align:start position:0% +about the relationship between the +position of the pole in the CT + + align:start position:0% +position of the pole in the CT + + + align:start position:0% +position of the pole in the CT +system and the position of the pole in + + align:start position:0% +system and the position of the pole in + + + align:start position:0% +system and the position of the pole in +the dt system because I know this + + align:start position:0% +the dt system because I know this + + + align:start position:0% +the dt system because I know this +original system the + + align:start position:0% + + + + align:start position:0% + +a I'm going to think of a as being 1 / s + + align:start position:0% +a I'm going to think of a as being 1 / s + + + align:start position:0% +a I'm going to think of a as being 1 / s +that's the applause transform + + align:start position:0% + + + + align:start position:0% + +transformation and I want that to be + + align:start position:0% +transformation and I want that to be + + + align:start position:0% +transformation and I want that to be +equivalent + + align:start position:0% +equivalent + + + align:start position:0% +equivalent +according to this map to some + + align:start position:0% +according to this map to some + + + align:start position:0% +according to this map to some +transformation in + + align:start position:0% +transformation in + + + align:start position:0% +transformation in +Z. Right? So I can look at this thing + + align:start position:0% +Z. Right? So I can look at this thing + + + align:start position:0% +Z. Right? So I can look at this thing +and I can see well that system function + + align:start position:0% +and I can see well that system function + + + align:start position:0% +and I can see well that system function +if I represent that whole block by a + + align:start position:0% +if I represent that whole block by a + + + align:start position:0% +if I represent that whole block by a +system function the system + + align:start position:0% +system function the system + + + align:start position:0% +system function the system +transformation is looks like + + align:start position:0% + + + + align:start position:0% + +that but ours that's the same as 1 / + + align:start position:0% + + + + align:start position:0% + +z but that's the same as t over z minus + + align:start position:0% +z but that's the same as t over z minus + + + align:start position:0% +z but that's the same as t over z minus +one. + + align:start position:0% +one. + + + align:start position:0% +one. +Apparently, there's a relationship + + align:start position:0% +Apparently, there's a relationship + + + align:start position:0% +Apparently, there's a relationship +between S and + + align:start position:0% +between S and + + + align:start position:0% +between S and +Z. In fact, Z minus one is ST. Z is 1 + + + align:start position:0% +Z. In fact, Z minus one is ST. Z is 1 + + + + align:start position:0% +Z. In fact, Z minus one is ST. Z is 1 + +ST. Regardless of how of what CT system + + align:start position:0% +ST. Regardless of how of what CT system + + + align:start position:0% +ST. Regardless of how of what CT system +I started + + align:start position:0% +I started + + + align:start position:0% +I started +with, if I use the Oiler forward + + align:start position:0% +with, if I use the Oiler forward + + + align:start position:0% +with, if I use the Oiler forward +relationship to make a DT approximation + + align:start position:0% +relationship to make a DT approximation + + + align:start position:0% +relationship to make a DT approximation +of the integrator, the resulting + + align:start position:0% +of the integrator, the resulting + + + align:start position:0% +of the integrator, the resulting +transformation will always have that + + align:start position:0% +transformation will always have that + + + align:start position:0% +transformation will always have that +property. + + align:start position:0% +property. + + + align:start position:0% +property. +That's exactly what we saw over here. + + align:start position:0% +That's exactly what we saw over here. + + + align:start position:0% +That's exactly what we saw over here. +So we think about the A's in the + + align:start position:0% +So we think about the A's in the + + + align:start position:0% +So we think about the A's in the +original system being mapped to + + align:start position:0% +original system being mapped to + + + align:start position:0% +original system being mapped to +something uh that's a little bit more + + align:start position:0% +something uh that's a little bit more + + + align:start position:0% +something uh that's a little bit more +complicated showed + + align:start position:0% +complicated showed + + + align:start position:0% +complicated showed +here but it's a DT + + align:start position:0% +here but it's a DT + + + align:start position:0% +here but it's a DT +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +representation and that DT + + align:start position:0% +representation and that DT + + + align:start position:0% +representation and that DT +representation always has this property + + align:start position:0% +representation always has this property + + + align:start position:0% +representation always has this property +that wherever the poles were in S I can + + align:start position:0% +that wherever the poles were in S I can + + + align:start position:0% +that wherever the poles were in S I can +find where the poles were in Z by taking + + align:start position:0% +find where the poles were in Z by taking + + + align:start position:0% +find where the poles were in Z by taking +Z = 1 plus ST + + align:start position:0% + + + + align:start position:0% + +t that's how we get from uh that's how + + align:start position:0% +t that's how we get from uh that's how + + + align:start position:0% +t that's how we get from uh that's how +we get the dependence on t if the + + align:start position:0% +we get the dependence on t if the + + + align:start position:0% +we get the dependence on t if the +original pole was like over here at + + align:start position:0% +original pole was like over here at + + + align:start position:0% +original pole was like over here at +minus1 over + + align:start position:0% +minus1 over + + + align:start position:0% +minus1 over +tow we just put u s = -1 / and we get + + align:start position:0% +tow we just put u s = -1 / and we get + + + align:start position:0% +tow we just put u s = -1 / and we get +precisely this relationship that we got + + align:start position:0% +precisely this relationship that we got + + + align:start position:0% +precisely this relationship that we got +before the 1 plus s t which is what I + + align:start position:0% +before the 1 plus s t which is what I + + + align:start position:0% +before the 1 plus s t which is what I +found here is the same as the 1 minus t + + align:start position:0% +found here is the same as the 1 minus t + + + align:start position:0% +found here is the same as the 1 minus t +over t tow that we found for the + + align:start position:0% +over t tow that we found for the + + + align:start position:0% +over t tow that we found for the +particular example of the leaky tank. + + align:start position:0% +particular example of the leaky tank. + + + align:start position:0% +particular example of the leaky tank. +Yes, I think you mentioned this earlier, + + align:start position:0% +Yes, I think you mentioned this earlier, + + + align:start position:0% +Yes, I think you mentioned this earlier, +but this is purely because of the + + align:start position:0% +but this is purely because of the + + + align:start position:0% +but this is purely because of the +mechanics of the forward oiler. Because + + align:start position:0% +mechanics of the forward oiler. Because + + + align:start position:0% +mechanics of the forward oiler. Because +of forward oiler, this is only true if I + + align:start position:0% +of forward oiler, this is only true if I + + + align:start position:0% +of forward oiler, this is only true if I +decide that all of my + + align:start position:0% +decide that all of my + + + align:start position:0% +decide that all of my +integrators are approximated using the + + align:start position:0% +integrators are approximated using the + + + align:start position:0% +integrators are approximated using the +forward oiler rule. It's absolutely + + align:start position:0% +forward oiler rule. It's absolutely + + + align:start position:0% +forward oiler rule. It's absolutely +true. Okay. And that's an interesting + + align:start position:0% +true. Okay. And that's an interesting + + + align:start position:0% +true. Okay. And that's an interesting +result. What it says is that if I think + + align:start position:0% +result. What it says is that if I think + + + align:start position:0% +result. What it says is that if I think +about how were the poles distributed in + + align:start position:0% +about how were the poles distributed in + + + align:start position:0% +about how were the poles distributed in +the splane, I just use that rule to + + align:start position:0% +the splane, I just use that rule to + + + align:start position:0% +the splane, I just use that rule to +figure out how they'll be distributed in + + align:start position:0% +figure out how they'll be distributed in + + + align:start position:0% +figure out how they'll be distributed in +the z + + align:start position:0% +the z + + + align:start position:0% +the z +plane. The rule says take the splane + + align:start position:0% +plane. The rule says take the splane + + + align:start position:0% +plane. The rule says take the splane +pole, scale it by capital t, and then + + align:start position:0% +pole, scale it by capital t, and then + + + align:start position:0% +pole, scale it by capital t, and then +shift the answer by one. + + align:start position:0% + + + + align:start position:0% + +Well, that's pretty interesting because + + align:start position:0% +Well, that's pretty interesting because + + + align:start position:0% +Well, that's pretty interesting because +that means that there are S's over + + align:start position:0% +that means that there are S's over + + + align:start position:0% +that means that there are S's over +here that when I go through that map end + + align:start position:0% +here that when I go through that map end + + + align:start position:0% +here that when I go through that map end +up outside the unit circle. That's + + align:start position:0% +up outside the unit circle. That's + + + align:start position:0% +up outside the unit circle. That's +exactly what I + + align:start position:0% +exactly what I + + + align:start position:0% +exactly what I +found. That transformation has the + + align:start position:0% +found. That transformation has the + + + align:start position:0% +found. That transformation has the +property that it can map a + + align:start position:0% +property that it can map a + + + align:start position:0% +property that it can map a +stable CT system, a perfectly well- + + align:start position:0% +stable CT system, a perfectly well- + + + align:start position:0% +stable CT system, a perfectly well- +behaved CT system into an oscilly or + + align:start position:0% +behaved CT system into an oscilly or + + + align:start position:0% +behaved CT system into an oscilly or +even a growing divergent DT system. And + + align:start position:0% +even a growing divergent DT system. And + + + align:start position:0% +even a growing divergent DT system. And +you can see that simply because of the + + align:start position:0% +you can see that simply because of the + + + align:start position:0% +you can see that simply because of the +map between uh Z and S. Had S been some + + align:start position:0% +map between uh Z and S. Had S been some + + + align:start position:0% +map between uh Z and S. Had S been some +number over + + align:start position:0% +number over + + + align:start position:0% +number over +here, the the uh response the the um + + align:start position:0% +here, the the uh response the the um + + + align:start position:0% +here, the the uh response the the um +unit impulse response of the CT system + + align:start position:0% +unit impulse response of the CT system + + + align:start position:0% +unit impulse response of the CT system +would have been completely well behaved + + align:start position:0% +would have been completely well behaved + + + align:start position:0% +would have been completely well behaved +e to the minus + + align:start position:0% +e to the minus + + + align:start position:0% +e to the minus +ST but the response to the DT equivalent + + align:start position:0% +ST but the response to the DT equivalent + + + align:start position:0% +ST but the response to the DT equivalent +would be badly behaved because it would + + align:start position:0% +would be badly behaved because it would + + + align:start position:0% +would be badly behaved because it would +have mapped outside the unit + + align:start position:0% +have mapped outside the unit + + + align:start position:0% +have mapped outside the unit +circle. Okay. And as you motivated the + + align:start position:0% +circle. Okay. And as you motivated the + + + align:start position:0% +circle. Okay. And as you motivated the +that's only true because I did oiler + + align:start position:0% +that's only true because I did oiler + + + align:start position:0% +that's only true because I did oiler +forward. I can do precisely the same + + align:start position:0% +forward. I can do precisely the same + + + align:start position:0% +forward. I can do precisely the same +analysis for backward + + align:start position:0% +analysis for backward + + + align:start position:0% +analysis for backward +oiler. Instead of approximating + + align:start position:0% +oiler. Instead of approximating + + + align:start position:0% +oiler. Instead of approximating +derivatives by looking forward in time + + align:start position:0% +derivatives by looking forward in time + + + align:start position:0% +derivatives by looking forward in time +like I did before, I could instead look + + align:start position:0% +like I did before, I could instead look + + + align:start position:0% +like I did before, I could instead look +backward in + + align:start position:0% + + + + align:start position:0% + +time. If I look backward in time, it + + align:start position:0% +time. If I look backward in time, it + + + align:start position:0% +time. If I look backward in time, it +looks almost the same. Now I say the + + align:start position:0% +looks almost the same. Now I say the + + + align:start position:0% +looks almost the same. Now I say the +derivative at the time n cap t is n + + align:start position:0% +derivative at the time n cap t is n + + + align:start position:0% +derivative at the time n cap t is n +minus n minus one. Look + + align:start position:0% +minus n minus one. Look + + + align:start position:0% +minus n minus one. Look +backwards. Seems like a trivial + + align:start position:0% +backwards. Seems like a trivial + + + align:start position:0% +backwards. Seems like a trivial +difference. But in fact the answer comes + + align:start position:0% +difference. But in fact the answer comes + + + align:start position:0% +difference. But in fact the answer comes +out completely different. If I look + + align:start position:0% +out completely different. If I look + + + align:start position:0% +out completely different. If I look +backwards in time instead let's see if I + + align:start position:0% +backwards in time instead let's see if I + + + align:start position:0% +backwards in time instead let's see if I +can. So if I look backwards in time + + align:start position:0% + + + + align:start position:0% + +instead what I can think about now is + + align:start position:0% +instead what I can think about now is + + + align:start position:0% +instead what I can think about now is +replacing every one of these a operators + + align:start position:0% +replacing every one of these a operators + + + align:start position:0% +replacing every one of these a operators +again. So think about a. A was this + + align:start position:0% +again. So think about a. A was this + + + align:start position:0% +again. So think about a. A was this +thing that Y came out of and Y dot must + + align:start position:0% +thing that Y came out of and Y dot must + + + align:start position:0% +thing that Y came out of and Y dot must +have gone into which was + + align:start position:0% + + + + align:start position:0% + +X and now I'm using oiler backward + + align:start position:0% +X and now I'm using oiler backward + + + align:start position:0% +X and now I'm using oiler backward +instead. So now I want um X of + + align:start position:0% +instead. So now I want um X of + + + align:start position:0% +instead. So now I want um X of +N should be look backwards in time. So I + + align:start position:0% +N should be look backwards in time. So I + + + align:start position:0% +N should be look backwards in time. So I +want y of n minus y of n minus + + align:start position:0% +want y of n minus y of n minus + + + align:start position:0% +want y of n minus y of n minus +one / + + align:start position:0% + + + + align:start position:0% + +t. So + + align:start position:0% +t. So + + + align:start position:0% +t. So +uh what this says is that I want to take + + align:start position:0% +uh what this says is that I want to take + + + align:start position:0% +uh what this says is that I want to take +y of n should be y of n minus one added + + align:start position:0% +y of n should be y of n minus one added + + + align:start position:0% +y of n should be y of n minus one added +to t * x of + + align:start position:0% +to t * x of + + + align:start position:0% +to t * x of +n. So that's a system that if I started + + align:start position:0% +n. So that's a system that if I started + + + align:start position:0% +n. So that's a system that if I started +with x of n and I wanted to generate y + + align:start position:0% +with x of n and I wanted to generate y + + + align:start position:0% +with x of n and I wanted to generate y +of + + align:start position:0% +of + + + align:start position:0% +of +n, it's almost the same as the other one + + align:start position:0% +n, it's almost the same as the other one + + + align:start position:0% +n, it's almost the same as the other one +except now it says when I want to + + align:start position:0% +except now it says when I want to + + + align:start position:0% +except now it says when I want to +construct y of n, start with a delayed + + align:start position:0% +construct y of n, start with a delayed + + + align:start position:0% +construct y of n, start with a delayed +version of y. How do I get a delayed + + align:start position:0% +version of y. How do I get a delayed + + + align:start position:0% +version of y. How do I get a delayed +version of + + align:start position:0% + + + + align:start position:0% + +y? Delay it. So I take + + align:start position:0% +y? Delay it. So I take + + + align:start position:0% +y? Delay it. So I take +y and I delay + + align:start position:0% +y and I delay + + + align:start position:0% +y and I delay +it like + + align:start position:0% + + + + align:start position:0% + +that. What comes out here is y of n + + align:start position:0% +that. What comes out here is y of n + + + align:start position:0% +that. What comes out here is y of n +minus + + align:start position:0% +minus + + + align:start position:0% +minus +one and then y of n is y of n minus one + + align:start position:0% +one and then y of n is y of n minus one + + + align:start position:0% +one and then y of n is y of n minus one +added + + align:start position:0% + + + + align:start position:0% + +to t * x + + align:start position:0% +to t * x + + + align:start position:0% +to t * x +ofn. So it's like + + align:start position:0% +ofn. So it's like + + + align:start position:0% +ofn. So it's like +that. It's almost the same, but the math + + align:start position:0% +that. It's almost the same, but the math + + + align:start position:0% +that. It's almost the same, but the math +is different, right? So now I'm + + align:start position:0% +is different, right? So now I'm + + + align:start position:0% +is different, right? So now I'm +replacing my A's, which are always 1 / s + + align:start position:0% +replacing my A's, which are always 1 / s + + + align:start position:0% +replacing my A's, which are always 1 / s +with a system that looks like t going + + align:start position:0% +with a system that looks like t going + + + align:start position:0% +with a system that looks like t going +forward divided by 1 - r in the + + align:start position:0% +forward divided by 1 - r in the + + + align:start position:0% +forward divided by 1 - r in the +bottom. So that's t over 1 - 1 / + + align:start position:0% +bottom. So that's t over 1 - 1 / + + + align:start position:0% +bottom. So that's t over 1 - 1 / +z. So that's zt over z minus + + align:start position:0% +z. So that's zt over z minus + + + align:start position:0% +z. So that's zt over z minus +one. So that means that z minus one + + align:start position:0% +one. So that means that z minus one + + + align:start position:0% +one. So that means that z minus one +now is s t + + align:start position:0% +now is s t + + + align:start position:0% +now is s t +z cross multiplying 1 - s t on z is 1. + + align:start position:0% +z cross multiplying 1 - s t on z is 1. + + + align:start position:0% +z cross multiplying 1 - s t on z is 1. +So z is 1 over 1 - s t. I got something + + align:start position:0% +So z is 1 over 1 - s t. I got something + + + align:start position:0% +So z is 1 over 1 - s t. I got something +that looks completely different. This is + + align:start position:0% +that looks completely different. This is + + + align:start position:0% +that looks completely different. This is +backward + + align:start position:0% +backward + + + align:start position:0% +backward +oiler. This is forward oiler. So the + + align:start position:0% +oiler. This is forward oiler. So the + + + align:start position:0% +oiler. This is forward oiler. So the +answer for forward oiler over here is 1 + + align:start position:0% +answer for forward oiler over here is 1 + + + align:start position:0% +answer for forward oiler over here is 1 +plus + + align:start position:0% +plus + + + align:start position:0% +plus +st. The answer for backward oiler is one + + align:start position:0% +st. The answer for backward oiler is one + + + align:start position:0% +st. The answer for backward oiler is one +one over 1 minus + + align:start position:0% +one over 1 minus + + + align:start position:0% +one over 1 minus +s. Everybody with + + align:start position:0% +s. Everybody with + + + align:start position:0% +s. Everybody with +me? So now when I think about where do + + align:start position:0% +me? So now when I think about where do + + + align:start position:0% +me? So now when I think about where do +the poles + + align:start position:0% +the poles + + + align:start position:0% +the poles +land if I make the backwards oiler + + align:start position:0% +land if I make the backwards oiler + + + align:start position:0% +land if I make the backwards oiler +approximation they fall on this + + align:start position:0% +approximation they fall on this + + + align:start position:0% +approximation they fall on this +relationship instead of the + + align:start position:0% +relationship instead of the + + + align:start position:0% +relationship instead of the +previous. And the interesting thing + + align:start position:0% +previous. And the interesting thing + + + align:start position:0% +previous. And the interesting thing +about that relationship is + + align:start position:0% + + + + align:start position:0% + +that if you think about the way this + + align:start position:0% +that if you think about the way this + + + align:start position:0% +that if you think about the way this +works, every point in the left half + + align:start position:0% +works, every point in the left half + + + align:start position:0% +works, every point in the left half +plane of + + align:start position:0% +plane of + + + align:start position:0% +plane of +S according to this + + align:start position:0% +S according to this + + + align:start position:0% +S according to this +map ends up inside a little circle in + + align:start position:0% +map ends up inside a little circle in + + + align:start position:0% +map ends up inside a little circle in +the Z domain. + + align:start position:0% +the Z domain. + + + align:start position:0% +the Z domain. +The entire left half + + align:start position:0% +The entire left half + + + align:start position:0% +The entire left half +plane maps into the circle that's shaded + + align:start position:0% +plane maps into the circle that's shaded + + + align:start position:0% +plane maps into the circle that's shaded +in the right. If you just make a + + align:start position:0% +in the right. If you just make a + + + align:start position:0% +in the right. If you just make a +picture, if you just think + + align:start position:0% +picture, if you just think + + + align:start position:0% +picture, if you just think +about plug in S= 1, where does Z happen? + + align:start position:0% +about plug in S= 1, where does Z happen? + + + align:start position:0% +about plug in S= 1, where does Z happen? +Plug in S= minus1, where's the new Z? + + align:start position:0% +Plug in S= minus1, where's the new Z? + + + align:start position:0% +Plug in S= minus1, where's the new Z? +You plug in S= 1 /T, where's the new Z? + + align:start position:0% +You plug in S= 1 /T, where's the new Z? + + + align:start position:0% +You plug in S= 1 /T, where's the new Z? +All of the values in the left half plane + + align:start position:0% +All of the values in the left half plane + + + align:start position:0% +All of the values in the left half plane +for S map inside a small + + align:start position:0% +for S map inside a small + + + align:start position:0% +for S map inside a small +circle in the Z + + align:start position:0% +circle in the Z + + + align:start position:0% +circle in the Z +plane. Which means + + align:start position:0% +plane. Which means + + + align:start position:0% +plane. Which means +that if the original system had a pole + + align:start position:0% +that if the original system had a pole + + + align:start position:0% +that if the original system had a pole +anywhere in the left half plane, + + align:start position:0% +anywhere in the left half plane, + + + align:start position:0% +anywhere in the left half plane, +remember left half planes, leftsided, + + align:start position:0% +remember left half planes, leftsided, + + + align:start position:0% +remember left half planes, leftsided, +we're thinking that those are the kinds + + align:start position:0% +we're thinking that those are the kinds + + + align:start position:0% +we're thinking that those are the kinds +of systems whose uh unit sample unit + + align:start position:0% +of systems whose uh unit sample unit + + + align:start position:0% +of systems whose uh unit sample unit +impulse responses converge toward zero. + + align:start position:0% +impulse responses converge toward zero. + + + align:start position:0% +impulse responses converge toward zero. +If you had a system who that had poles + + align:start position:0% +If you had a system who that had poles + + + align:start position:0% +If you had a system who that had poles +in the left half plane and you do the + + align:start position:0% +in the left half plane and you do the + + + align:start position:0% +in the left half plane and you do the +backwards oiler transformation, you're + + align:start position:0% +backwards oiler transformation, you're + + + align:start position:0% +backwards oiler transformation, you're +guaranteed to get a system that has + + align:start position:0% +guaranteed to get a system that has + + + align:start position:0% +guaranteed to get a system that has +poles inside the unit + + align:start position:0% +poles inside the unit + + + align:start position:0% +poles inside the unit +circle. In fact, they're in a smaller + + align:start position:0% +circle. In fact, they're in a smaller + + + align:start position:0% +circle. In fact, they're in a smaller +circle than the unit + + align:start position:0% +circle than the unit + + + align:start position:0% +circle than the unit +circle. Okay, everybody sort of know + + align:start position:0% +circle. Okay, everybody sort of know + + + align:start position:0% +circle. Okay, everybody sort of know +what I'm talking about? + + align:start position:0% +what I'm talking about? + + + align:start position:0% +what I'm talking about? +So this is the idea of thinking about + + align:start position:0% +So this is the idea of thinking about + + + align:start position:0% +So this is the idea of thinking about +not relationships among DT + + align:start position:0% +not relationships among DT + + + align:start position:0% +not relationships among DT +representations or representations among + + align:start position:0% +representations or representations among + + + align:start position:0% +representations or representations among +CT systems but relations between CT and + + align:start position:0% +CT systems but relations between CT and + + + align:start position:0% +CT systems but relations between CT and +DT. It's because we can cast each of + + align:start position:0% +DT. It's because we can cast each of + + + align:start position:0% +DT. It's because we can cast each of +those kinds of systems into a polomial + + align:start position:0% +those kinds of systems into a polomial + + + align:start position:0% +those kinds of systems into a polomial +representation that we can make a + + align:start position:0% +representation that we can make a + + + align:start position:0% +representation that we can make a +correspondence between the CT system and + + align:start position:0% +correspondence between the CT system and + + + align:start position:0% +correspondence between the CT system and +the DT approximation. I'll talk about + + align:start position:0% +the DT approximation. I'll talk about + + + align:start position:0% +the DT approximation. I'll talk about +just one more and that's the trapezoid + + align:start position:0% +just one more and that's the trapezoid + + + align:start position:0% +just one more and that's the trapezoid +rule which is what you did in homework + + align:start position:0% +rule which is what you did in homework + + + align:start position:0% +rule which is what you did in homework +two. You may remember homework two right + + align:start position:0% +two. You may remember homework two right + + + align:start position:0% +two. You may remember homework two right +since it was due like yesterday. Uh so + + align:start position:0% +since it was due like yesterday. Uh so + + + align:start position:0% +since it was due like yesterday. Uh so +the last problem in homework two had to + + align:start position:0% +the last problem in homework two had to + + + align:start position:0% +the last problem in homework two had to +do with finding a numerical + + align:start position:0% +do with finding a numerical + + + align:start position:0% +do with finding a numerical +approximation to the mass and spring + + align:start position:0% +approximation to the mass and spring + + + align:start position:0% +approximation to the mass and spring +system. And if you remember we did three + + align:start position:0% +system. And if you remember we did three + + + align:start position:0% +system. And if you remember we did three +of them. Those three were actually + + align:start position:0% +of them. Those three were actually + + + align:start position:0% +of them. Those three were actually +forward oiler, backward oiler and + + align:start position:0% +forward oiler, backward oiler and + + + align:start position:0% +forward oiler, backward oiler and +trapezoidal rule. + + align:start position:0% +trapezoidal rule. + + + align:start position:0% +trapezoidal rule. +trapezoidal rule says okay I didn't like + + align:start position:0% +trapezoidal rule says okay I didn't like + + + align:start position:0% +trapezoidal rule says okay I didn't like +this idea of looking + + align:start position:0% +this idea of looking + + + align:start position:0% +this idea of looking +forward that seems + + align:start position:0% +forward that seems + + + align:start position:0% +forward that seems +anti-ymmetric what's special about + + align:start position:0% +anti-ymmetric what's special about + + + align:start position:0% +anti-ymmetric what's special about +forwards or backwards that's also + + align:start position:0% +forwards or backwards that's also + + + align:start position:0% +forwards or backwards that's also +treating backwards special I want to + + align:start position:0% +treating backwards special I want to + + + align:start position:0% +treating backwards special I want to +treat it symmetric in time that's what + + align:start position:0% +treat it symmetric in time that's what + + + align:start position:0% +treat it symmetric in time that's what +the centered difference approximation + + align:start position:0% +the centered difference approximation + + + align:start position:0% +the centered difference approximation +did the center difference approximation + + align:start position:0% +did the center difference approximation + + + align:start position:0% +did the center difference approximation +in homework two was based on a + + align:start position:0% +in homework two was based on a + + + align:start position:0% +in homework two was based on a +trapezoidal rule the trapezoidal rule + + align:start position:0% +trapezoidal rule the trapezoidal rule + + + align:start position:0% +trapezoidal rule the trapezoidal rule +says okay let me approximate my DT + + align:start position:0% + + + + align:start position:0% + +output. Let me let me think about a + + align:start position:0% +output. Let me let me think about a + + + align:start position:0% +output. Let me let me think about a +sequence of samples in a DT output. Y + + align:start position:0% +sequence of samples in a DT output. Y + + + align:start position:0% +sequence of samples in a DT output. Y +then let me force the differential + + align:start position:0% +then let me force the differential + + + align:start position:0% +then let me force the differential +equation to be true at every point + + align:start position:0% +equation to be true at every point + + + align:start position:0% +equation to be true at every point +between + + align:start position:0% + + + + align:start position:0% + +samples in the forward oiler and the + + align:start position:0% +samples in the forward oiler and the + + + align:start position:0% +samples in the forward oiler and the +backward. We forced the differential + + align:start position:0% +backward. We forced the differential + + + align:start position:0% +backward. We forced the differential +equation to be true at integers n. + + align:start position:0% +equation to be true at integers n. + + + align:start position:0% +equation to be true at integers n. +that made us compute derivatives by + + align:start position:0% +that made us compute derivatives by + + + align:start position:0% +that made us compute derivatives by +looking forward or backwards. In a + + align:start position:0% +looking forward or backwards. In a + + + align:start position:0% +looking forward or backwards. In a +trapezoidal rule, we force the + + align:start position:0% +trapezoidal rule, we force the + + + align:start position:0% +trapezoidal rule, we force the +differential equation to be true between + + align:start position:0% +differential equation to be true between + + + align:start position:0% +differential equation to be true between +samples. Then we say okay the the signal + + align:start position:0% +samples. Then we say okay the the signal + + + align:start position:0% +samples. Then we say okay the the signal +yc should be the average of those + + align:start position:0% +yc should be the average of those + + + align:start position:0% +yc should be the average of those +samples and the derivative should be the + + align:start position:0% +samples and the derivative should be the + + + align:start position:0% +samples and the derivative should be the +difference of the two samples divided by + + align:start position:0% +difference of the two samples divided by + + + align:start position:0% +difference of the two samples divided by +t. So they're + + align:start position:0% +t. So they're + + + align:start position:0% +t. So they're +centered. Everybody see that? So, we're + + align:start position:0% +centered. Everybody see that? So, we're + + + align:start position:0% +centered. Everybody see that? So, we're +going to force the differential equation + + align:start position:0% +going to force the differential equation + + + align:start position:0% +going to force the differential equation +to be true at points between the samples + + align:start position:0% +to be true at points between the samples + + + align:start position:0% +to be true at points between the samples +of the difference + + align:start position:0% +of the difference + + + align:start position:0% +of the difference +equation. And that's going to give me a + + align:start position:0% +equation. And that's going to give me a + + + align:start position:0% +equation. And that's going to give me a +different kind of relationship that + + align:start position:0% +different kind of relationship that + + + align:start position:0% +different kind of relationship that +looks strikingly the same as these kinds + + align:start position:0% +looks strikingly the same as these kinds + + + align:start position:0% +looks strikingly the same as these kinds +of + + align:start position:0% +of + + + align:start position:0% +of +relationships. Okay. So now I'm going to + + align:start position:0% +relationships. Okay. So now I'm going to + + + align:start position:0% +relationships. Okay. So now I'm going to +say + + align:start position:0% + + + + align:start position:0% + +um that I would like to + + align:start position:0% +um that I would like to + + + align:start position:0% +um that I would like to +have a which maps y dot is + + align:start position:0% +have a which maps y dot is + + + align:start position:0% +have a which maps y dot is +x except now what I'm going to want to + + align:start position:0% +x except now what I'm going to want to + + + align:start position:0% +x except now what I'm going to want to +say is that + + align:start position:0% +say is that + + + align:start position:0% +say is that +uh x which I will represent as the + + align:start position:0% +uh x which I will represent as the + + + align:start position:0% +uh x which I will represent as the +average of the nth and n minus + + align:start position:0% + + + + align:start position:0% + +one should be constrained to be the + + align:start position:0% +one should be constrained to be the + + + align:start position:0% +one should be constrained to be the +derivative of this guy which I will + + align:start position:0% +derivative of this guy which I will + + + align:start position:0% +derivative of this guy which I will +do by looking at the corresponding + + align:start position:0% +do by looking at the corresponding + + + align:start position:0% +do by looking at the corresponding +values of + + align:start position:0% + + + + align:start position:0% + +y. + + align:start position:0% +y. + + + align:start position:0% +y. +Okay. And so that gives me a different + + align:start position:0% +Okay. And so that gives me a different + + + align:start position:0% +Okay. And so that gives me a different +way of doing the approximation. I get y + + align:start position:0% +way of doing the approximation. I get y + + + align:start position:0% +way of doing the approximation. I get y +of n should be y of n minus one + + align:start position:0% +of n should be y of n minus one + + + align:start position:0% +of n should be y of n minus one +uh let's see plus t / 2 x of n + x of n + + align:start position:0% +uh let's see plus t / 2 x of n + x of n + + + align:start position:0% +uh let's see plus t / 2 x of n + x of n +minus + + align:start position:0% + + + + align:start position:0% + +one. Just a different rule for how to do + + align:start position:0% +one. Just a different rule for how to do + + + align:start position:0% +one. Just a different rule for how to do +the derivative. That's all I've done. + + align:start position:0% +the derivative. That's all I've done. + + + align:start position:0% +the derivative. That's all I've done. +But it gives me a different kind of a + + align:start position:0% +But it gives me a different kind of a + + + align:start position:0% +But it gives me a different kind of a +system. Now I want to have x of n go + + align:start position:0% +system. Now I want to have x of n go + + + align:start position:0% +system. Now I want to have x of n go +into something that I will make my new a + + align:start position:0% +into something that I will make my new a + + + align:start position:0% +into something that I will make my new a +boxes. Uh to compute y of n I should + + align:start position:0% +boxes. Uh to compute y of n I should + + + align:start position:0% +boxes. Uh to compute y of n I should +have a delayed version. Well that's + + align:start position:0% +have a delayed version. Well that's + + + align:start position:0% +have a delayed version. Well that's +easy. I make one of + + align:start position:0% + + + + align:start position:0% + +those and y of n should be the sum of + + align:start position:0% +those and y of n should be the sum of + + + align:start position:0% +those and y of n should be the sum of +the delayed + + align:start position:0% + + + + align:start position:0% + +version and t over + + align:start position:0% +version and t over + + + align:start position:0% +version and t over +two times a delayed version of x. So + + align:start position:0% +two times a delayed version of x. So + + + align:start position:0% +two times a delayed version of x. So +I'll have to do + + align:start position:0% + + + + align:start position:0% + +this. So now I have the sum of x and a + + align:start position:0% +this. So now I have the sum of x and a + + + align:start position:0% +this. So now I have the sum of x and a +delayed version of x and I put that + + align:start position:0% +delayed version of x and I put that + + + align:start position:0% +delayed version of x and I put that +through t + + align:start position:0% + + + + align:start position:0% + +/2. So here's my new discrete + + align:start position:0% +/2. So here's my new discrete + + + align:start position:0% +/2. So here's my new discrete +approximation to the + + align:start position:0% + + + + align:start position:0% + +accumulator and I do just the same thing + + align:start position:0% +accumulator and I do just the same thing + + + align:start position:0% +accumulator and I do just the same thing +I did before. I say + + align:start position:0% +I did before. I say + + + align:start position:0% +I did before. I say +um what's the value of what's the + + align:start position:0% +um what's the value of what's the + + + align:start position:0% +um what's the value of what's the +relationship between S and Z. + + align:start position:0% + + + + align:start position:0% + +So my a which is the same as 1 / s now + + align:start position:0% +So my a which is the same as 1 / s now + + + align:start position:0% +So my a which is the same as 1 / s now +becomes that block diagram which looks + + align:start position:0% +becomes that block diagram which looks + + + align:start position:0% +becomes that block diagram which looks +like t over two uh looks like r + + + align:start position:0% +like t over two uh looks like r + + + + align:start position:0% +like t over two uh looks like r + +one see 1 plus r. Let's do it the other + + align:start position:0% +one see 1 plus r. Let's do it the other + + + align:start position:0% +one see 1 plus r. Let's do it the other +way. So t over 2 1 plus + + align:start position:0% +way. So t over 2 1 plus + + + align:start position:0% +way. So t over 2 1 plus +r 1 minus + + align:start position:0% +r 1 minus + + + align:start position:0% +r 1 minus +r. So t over two from here, 1 plus r + + align:start position:0% +r. So t over two from here, 1 plus r + + + align:start position:0% +r. So t over two from here, 1 plus r +from here, one over 1 minus r from + + align:start position:0% + + + + align:start position:0% + +there. Uh which I can convert into z and + + align:start position:0% +there. Uh which I can convert into z and + + + align:start position:0% +there. Uh which I can convert into z and +I'll get t / 2 z + 1 / z minus + + align:start position:0% + + + + align:start position:0% + +one. I don't think I made any mistakes + + align:start position:0% +one. I don't think I made any mistakes + + + align:start position:0% +one. I don't think I made any mistakes +yet. + + align:start position:0% +yet. + + + align:start position:0% +yet. +So then I get + + align:start position:0% +So then I get + + + align:start position:0% +So then I get +um so z + one uh z minus + + align:start position:0% + + + + align:start position:0% + +one bring that over there bring that + + align:start position:0% +one bring that over there bring that + + + align:start position:0% +one bring that over there bring that +over there st over 2 z + + + align:start position:0% + + + + align:start position:0% + +one and now bring the z's over here 1 + + align:start position:0% +one and now bring the z's over here 1 + + + align:start position:0% +one and now bring the z's over here 1 +minus s t over 2 operates on z to give + + align:start position:0% +minus s t over 2 operates on z to give + + + align:start position:0% +minus s t over 2 operates on z to give +me + + align:start position:0% +me + + + align:start position:0% +me +1 + s t / + + align:start position:0% +1 + s t / + + + align:start position:0% +1 + s t / +2. So + + align:start position:0% +2. So + + + align:start position:0% +2. So +z is 1 + s t /2 over 1 - s t + + align:start position:0% +z is 1 + s t /2 over 1 - s t + + + align:start position:0% +z is 1 + s t /2 over 1 - s t +over2. So that's my new transformation + + align:start position:0% +over2. So that's my new transformation + + + align:start position:0% +over2. So that's my new transformation +based on the trapezoidal + + align:start position:0% +based on the trapezoidal + + + align:start position:0% +based on the trapezoidal +rule which is showed here. Hopefully + + align:start position:0% +rule which is showed here. Hopefully + + + align:start position:0% +rule which is showed here. Hopefully +they match. So z maps to 1 + s t /2 / 1 + + align:start position:0% +they match. So z maps to 1 + s t /2 / 1 + + + align:start position:0% +they match. So z maps to 1 + s t /2 / 1 +- s t over2. And the interesting thing + + align:start position:0% +- s t over2. And the interesting thing + + + align:start position:0% +- s t over2. And the interesting thing +about that transformation is that it + + align:start position:0% +about that transformation is that it + + + align:start position:0% +about that transformation is that it +maps the entire left half plane of + + align:start position:0% +maps the entire left half plane of + + + align:start position:0% +maps the entire left half plane of +S precisely into the unit + + align:start position:0% + + + + align:start position:0% + +circle. That was the reason that the + + align:start position:0% +circle. That was the reason that the + + + align:start position:0% +circle. That was the reason that the +trapezoidal rule worked so much better + + align:start position:0% +trapezoidal rule worked so much better + + + align:start position:0% +trapezoidal rule worked so much better +on the problems that you tried in + + align:start position:0% +on the problems that you tried in + + + align:start position:0% +on the problems that you tried in +homework two. + + align:start position:0% +homework two. + + + align:start position:0% +homework two. +So if the pole starts out being + + align:start position:0% +So if the pole starts out being + + + align:start position:0% +So if the pole starts out being +real so that it's someplace in the s + + align:start position:0% +real so that it's someplace in the s + + + align:start position:0% +real so that it's someplace in the s +plane on this red + + align:start position:0% +plane on this red + + + align:start position:0% +plane on this red +arrow, oiler forward gave us a pole in + + align:start position:0% +arrow, oiler forward gave us a pole in + + + align:start position:0% +arrow, oiler forward gave us a pole in +the z plane that could be if t is big + + align:start position:0% +the z plane that could be if t is big + + + align:start position:0% +the z plane that could be if t is big +enough outside the unit + + align:start position:0% +enough outside the unit + + + align:start position:0% +enough outside the unit +circle. In the oiler backwards method, + + align:start position:0% +circle. In the oiler backwards method, + + + align:start position:0% +circle. In the oiler backwards method, +it always lands someplace in the unit + + align:start position:0% +it always lands someplace in the unit + + + align:start position:0% +it always lands someplace in the unit +circle. In the trapezoidal rule, it + + align:start position:0% +circle. In the trapezoidal rule, it + + + align:start position:0% +circle. In the trapezoidal rule, it +lands someplace in the unit + + align:start position:0% +lands someplace in the unit + + + align:start position:0% +lands someplace in the unit +circle. But in the mass spring problem, + + align:start position:0% +circle. But in the mass spring problem, + + + align:start position:0% +circle. But in the mass spring problem, +the poles were on the imaginary + + align:start position:0% +the poles were on the imaginary + + + align:start position:0% +the poles were on the imaginary +axis, which means that in the oiler + + align:start position:0% +axis, which means that in the oiler + + + align:start position:0% +axis, which means that in the oiler +forward method, the poles went outside + + align:start position:0% +forward method, the poles went outside + + + align:start position:0% +forward method, the poles went outside +the unit circle. That's the reason the + + align:start position:0% +the unit circle. That's the reason the + + + align:start position:0% +the unit circle. That's the reason the +solution to the mass spring problem + + align:start position:0% +solution to the mass spring problem + + + align:start position:0% +solution to the mass spring problem +diverged. + + align:start position:0% + + + + align:start position:0% + +In the oiler backward method, the poles + + align:start position:0% +In the oiler backward method, the poles + + + align:start position:0% +In the oiler backward method, the poles +that were on the J omega axis mapped to + + align:start position:0% +that were on the J omega axis mapped to + + + align:start position:0% +that were on the J omega axis mapped to +the perimeter of this inside circle. + + align:start position:0% +the perimeter of this inside circle. + + + align:start position:0% +the perimeter of this inside circle. +That's why they converged even though + + align:start position:0% +That's why they converged even though + + + align:start position:0% +That's why they converged even though +the mass spring system should have + + align:start position:0% +the mass spring system should have + + + align:start position:0% +the mass spring system should have +oscillated + + align:start position:0% +oscillated + + + align:start position:0% +oscillated +forever in the solution that you did + + align:start position:0% +forever in the solution that you did + + + align:start position:0% +forever in the solution that you did +with oiler backwards. It converged and + + align:start position:0% +with oiler backwards. It converged and + + + align:start position:0% +with oiler backwards. It converged and +that's because it ma the method maps + + align:start position:0% +that's because it ma the method maps + + + align:start position:0% +that's because it ma the method maps +poles on the J omega axis inside the + + align:start position:0% +poles on the J omega axis inside the + + + align:start position:0% +poles on the J omega axis inside the +unit circle. That's not what we want. + + align:start position:0% +unit circle. That's not what we want. + + + align:start position:0% +unit circle. That's not what we want. +What we want for the mass spring system + + align:start position:0% +What we want for the mass spring system + + + align:start position:0% +What we want for the mass spring system +is to map the J omega poles directly + + align:start position:0% +is to map the J omega poles directly + + + align:start position:0% +is to map the J omega poles directly +onto the unit circle so that pure + + align:start position:0% +onto the unit circle so that pure + + + align:start position:0% +onto the unit circle so that pure +oscillations over here corresponds to + + align:start position:0% +oscillations over here corresponds to + + + align:start position:0% +oscillations over here corresponds to +pure oscillations over there and that's + + align:start position:0% +pure oscillations over there and that's + + + align:start position:0% +pure oscillations over there and that's +exactly what the trapezoidal rule + + align:start position:0% + + + + align:start position:0% + +does. Okay. So the point then the and + + align:start position:0% +does. Okay. So the point then the and + + + align:start position:0% +does. Okay. So the point then the and +this was the solution to that homework + + align:start position:0% +this was the solution to that homework + + + align:start position:0% +this was the solution to that homework +problem. + + align:start position:0% +problem. + + + align:start position:0% +problem. +So the point is that not only are we + + align:start position:0% +So the point is that not only are we + + + align:start position:0% +So the point is that not only are we +interested in figuring out relationships + + align:start position:0% +interested in figuring out relationships + + + align:start position:0% +interested in figuring out relationships +among the different representations for + + align:start position:0% +among the different representations for + + + align:start position:0% +among the different representations for +CT systems and among the different + + align:start position:0% +CT systems and among the different + + + align:start position:0% +CT systems and among the different +representations for DT systems, there's + + align:start position:0% +representations for DT systems, there's + + + align:start position:0% +representations for DT systems, there's +a lot of insight that you can get, + + align:start position:0% +a lot of insight that you can get, + + + align:start position:0% +a lot of insight that you can get, +especially into things like numerical + + align:start position:0% +especially into things like numerical + + + align:start position:0% +especially into things like numerical +approximations by thinking about how the + + align:start position:0% +approximations by thinking about how the + + + align:start position:0% +approximations by thinking about how the +relationships in one domain map to the \ No newline at end of file diff --git a/qEBi0K5wfOs.txt b/qEBi0K5wfOs.txt new file mode 100644 index 0000000000000000000000000000000000000000..839efdaf2536689d7c5a8780a5e51acc43cea8ee --- /dev/null +++ b/qEBi0K5wfOs.txt @@ -0,0 +1,1715 @@ +align:start position:0% + +hello welcome back to recitation I'm + + align:start position:0% +hello welcome back to recitation I'm + + + align:start position:0% +hello welcome back to recitation I'm +sure you're becoming more and more + + align:start position:0% +sure you're becoming more and more + + + align:start position:0% +sure you're becoming more and more +familiar with the determinants of + + align:start position:0% +familiar with the determinants of + + + align:start position:0% +familiar with the determinants of +matrices in the lecture we also learned + + align:start position:0% +matrices in the lecture we also learned + + + align:start position:0% +matrices in the lecture we also learned +the geometric interpretation of the + + align:start position:0% +the geometric interpretation of the + + + align:start position:0% +the geometric interpretation of the +determinant the absolute value of the + + align:start position:0% +determinant the absolute value of the + + + align:start position:0% +determinant the absolute value of the +determinant of a matrix is simply equal + + align:start position:0% +determinant of a matrix is simply equal + + + align:start position:0% +determinant of a matrix is simply equal +to the volume of the parallelepiped + + align:start position:0% +to the volume of the parallelepiped + + + align:start position:0% +to the volume of the parallelepiped +spent by the row vectors of the matrix + + align:start position:0% +spent by the row vectors of the matrix + + + align:start position:0% +spent by the row vectors of the matrix +so today we're going to apply this fact + + align:start position:0% +so today we're going to apply this fact + + + align:start position:0% +so today we're going to apply this fact +to solve the following problem I have a + + align:start position:0% +to solve the following problem I have a + + + align:start position:0% +to solve the following problem I have a +tetrahedron T in this 3d space and the + + align:start position:0% +tetrahedron T in this 3d space and the + + + align:start position:0% +tetrahedron T in this 3d space and the +vertices of T are given by au which is + + align:start position:0% +vertices of T are given by au which is + + + align:start position:0% +vertices of T are given by au which is +the origin a 1 a 2 and a 3 so I have + + align:start position:0% +the origin a 1 a 2 and a 3 so I have + + + align:start position:0% +the origin a 1 a 2 and a 3 so I have +highlighted this tetrahedron using the + + align:start position:0% +highlighted this tetrahedron using the + + + align:start position:0% +highlighted this tetrahedron using the +blue chalk so this is T and our first + + align:start position:0% +blue chalk so this is T and our first + + + align:start position:0% +blue chalk so this is T and our first +goal is to compute the volume of T using + + align:start position:0% +goal is to compute the volume of T using + + + align:start position:0% +goal is to compute the volume of T using +the determinant and the second part is + + align:start position:0% +the determinant and the second part is + + + align:start position:0% +the determinant and the second part is +if I fix a 1 and a 2 + + align:start position:0% +if I fix a 1 and a 2 + + + align:start position:0% +if I fix a 1 and a 2 +but moving a 3 to another point a 3 + + align:start position:0% +but moving a 3 to another point a 3 + + + align:start position:0% +but moving a 3 to another point a 3 +prime which is given by this coordinate + + align:start position:0% +prime which is given by this coordinate + + + align:start position:0% +prime which is given by this coordinate +I ask you to compute the volume again ok + + align:start position:0% +I ask you to compute the volume again ok + + + align:start position:0% +I ask you to compute the volume again ok +so since we want to use the fact that + + align:start position:0% +so since we want to use the fact that + + + align:start position:0% +so since we want to use the fact that +the determinant is related to the volume + + align:start position:0% +the determinant is related to the volume + + + align:start position:0% +the determinant is related to the volume +we have to figure out that which volume + + align:start position:0% +we have to figure out that which volume + + + align:start position:0% +we have to figure out that which volume +we should be looking at we know that the + + align:start position:0% +we should be looking at we know that the + + + align:start position:0% +we should be looking at we know that the +determinant is related the volume of a + + align:start position:0% +determinant is related the volume of a + + + align:start position:0% +determinant is related the volume of a +parallelepiped but here we only have a + + align:start position:0% +parallelepiped but here we only have a + + + align:start position:0% +parallelepiped but here we only have a +tetrahedron so the first goal should be + + align:start position:0% +tetrahedron so the first goal should be + + + align:start position:0% +tetrahedron so the first goal should be +to find out which parapet you should be + + align:start position:0% +to find out which parapet you should be + + + align:start position:0% +to find out which parapet you should be +working with ok why don't she hit the + + align:start position:0% +working with ok why don't she hit the + + + align:start position:0% +working with ok why don't she hit the +pause try to work it out yourself you + + align:start position:0% +pause try to work it out yourself you + + + align:start position:0% +pause try to work it out yourself you +can sketch the parallelepiped on this + + align:start position:0% +can sketch the parallelepiped on this + + + align:start position:0% +can sketch the parallelepiped on this +picture and I will return in a while and + + align:start position:0% +picture and I will return in a while and + + + align:start position:0% +picture and I will return in a while and +continue working with you + + align:start position:0% + + + + align:start position:0% + +all right how did your computation go + + align:start position:0% +all right how did your computation go + + + align:start position:0% +all right how did your computation go +now let's complete complete this picture + + align:start position:0% +now let's complete complete this picture + + + align:start position:0% +now let's complete complete this picture +together + + align:start position:0% +together + + + align:start position:0% +together +as we were saying we need a parallel + + align:start position:0% +as we were saying we need a parallel + + + align:start position:0% +as we were saying we need a parallel +pipette so that we can use the fact that + + align:start position:0% +pipette so that we can use the fact that + + + align:start position:0% +pipette so that we can use the fact that +the determinant is related to the volume + + align:start position:0% +the determinant is related to the volume + + + align:start position:0% +the determinant is related to the volume +here I have a tetrahedron and let's look + + align:start position:0% +here I have a tetrahedron and let's look + + + align:start position:0% +here I have a tetrahedron and let's look +at these three edges Oh a 1 Oh a 2 in Oh + + align:start position:0% +at these three edges Oh a 1 Oh a 2 in Oh + + + align:start position:0% +at these three edges Oh a 1 Oh a 2 in Oh +a 3 all of them meet at the origin so + + align:start position:0% +a 3 all of them meet at the origin so + + + align:start position:0% +a 3 all of them meet at the origin so +why don't we just consider the power + + align:start position:0% +why don't we just consider the power + + + align:start position:0% +why don't we just consider the power +pipette spent by the same three edges + + align:start position:0% +pipette spent by the same three edges + + + align:start position:0% +pipette spent by the same three edges +it's a natural choice because at least + + align:start position:0% +it's a natural choice because at least + + + align:start position:0% +it's a natural choice because at least +it shares three edges with T okay now + + align:start position:0% +it shares three edges with T okay now + + + align:start position:0% +it shares three edges with T okay now +let's move on to this picture here as + + align:start position:0% +let's move on to this picture here as + + + align:start position:0% +let's move on to this picture here as +you can see I have joined this prototype + + align:start position:0% +you can see I have joined this prototype + + + align:start position:0% +you can see I have joined this prototype +it in red chalk so the blue part is my + + align:start position:0% +it in red chalk so the blue part is my + + + align:start position:0% +it in red chalk so the blue part is my +original T in the red part let me call + + align:start position:0% +original T in the red part let me call + + + align:start position:0% +original T in the red part let me call +it P is the power pipette spent by edge + + align:start position:0% +it P is the power pipette spent by edge + + + align:start position:0% +it P is the power pipette spent by edge +Oh a 1 Oh a 2 and O is 3 so that's the + + align:start position:0% +Oh a 1 Oh a 2 and O is 3 so that's the + + + align:start position:0% +Oh a 1 Oh a 2 and O is 3 so that's the +parallel pipette then I'm going to work + + align:start position:0% +parallel pipette then I'm going to work + + + align:start position:0% +parallel pipette then I'm going to work +with now the next step is to relate the + + align:start position:0% +with now the next step is to relate the + + + align:start position:0% +with now the next step is to relate the +volume of T to the volume of P ok let's + + align:start position:0% +volume of T to the volume of P ok let's + + + align:start position:0% +volume of T to the volume of P ok let's +record together what is the volume of a + + align:start position:0% +record together what is the volume of a + + + align:start position:0% +record together what is the volume of a +tetrahedron we note that the volume of a + + align:start position:0% +tetrahedron we note that the volume of a + + + align:start position:0% +tetrahedron we note that the volume of a +tetrahedron is going to be equal to one + + align:start position:0% +tetrahedron is going to be equal to one + + + align:start position:0% +tetrahedron is going to be equal to one +third of the area of the base times the + + align:start position:0% +third of the area of the base times the + + + align:start position:0% +third of the area of the base times the +height right of course you can choose + + align:start position:0% +height right of course you can choose + + + align:start position:0% +height right of course you can choose +any side any phase to be the base but + + align:start position:0% +any side any phase to be the base but + + + align:start position:0% +any side any phase to be the base but +for convenience we're going to choose + + align:start position:0% +for convenience we're going to choose + + + align:start position:0% +for convenience we're going to choose +the triangle Oh a-one a-two to be the + + align:start position:0% +the triangle Oh a-one a-two to be the + + + align:start position:0% +the triangle Oh a-one a-two to be the +base of T so volume of T is going to be + + align:start position:0% +base of T so volume of T is going to be + + + align:start position:0% +base of T so volume of T is going to be +equal to 1/3 times the area of triangle + + align:start position:0% +equal to 1/3 times the area of triangle + + + align:start position:0% +equal to 1/3 times the area of triangle +Oh a 1 a 2 so I use this a to indicate + + align:start position:0% +Oh a 1 a 2 so I use this a to indicate + + + align:start position:0% +Oh a 1 a 2 so I use this a to indicate +the area then times the height well if I + + align:start position:0% +the area then times the height well if I + + + align:start position:0% +the area then times the height well if I +choose this to be my base then this a 3 + + align:start position:0% +choose this to be my base then this a 3 + + + align:start position:0% +choose this to be my base then this a 3 +becomes the apex then the height is + + align:start position:0% +becomes the apex then the height is + + + align:start position:0% +becomes the apex then the height is +simply equal to the distance from a 3 to + + align:start position:0% +simply equal to the distance from a 3 to + + + align:start position:0% +simply equal to the distance from a 3 to +the triangle + + align:start position:0% +the triangle + + + align:start position:0% +the triangle +Oh a 1 a 2 let me use letter H to denote + + align:start position:0% +Oh a 1 a 2 let me use letter H to denote + + + align:start position:0% +Oh a 1 a 2 let me use letter H to denote +this quantity so that's the height and + + align:start position:0% +this quantity so that's the height and + + + align:start position:0% +this quantity so that's the height and +the volume of T is equal to 1/3 of the + + align:start position:0% +the volume of T is equal to 1/3 of the + + + align:start position:0% +the volume of T is equal to 1/3 of the +product of the area of the base times + + align:start position:0% +product of the area of the base times + + + align:start position:0% +product of the area of the base times +the height ok this is the volume of T + + align:start position:0% +the height ok this is the volume of T + + + align:start position:0% +the height ok this is the volume of T +now let's see what the volume of what + + align:start position:0% +now let's see what the volume of what + + + align:start position:0% +now let's see what the volume of what +the volume of P is so P is Apollo pipe + + align:start position:0% +the volume of P is so P is Apollo pipe + + + align:start position:0% +the volume of P is so P is Apollo pipe +it the volume of a power pipette is + + align:start position:0% +it the volume of a power pipette is + + + align:start position:0% +it the volume of a power pipette is +simply equal to the area of the base + + align:start position:0% +simply equal to the area of the base + + + align:start position:0% +simply equal to the area of the base +times its height this time which phase + + align:start position:0% +times its height this time which phase + + + align:start position:0% +times its height this time which phase +would you choose to be the base well of + + align:start position:0% +would you choose to be the base well of + + + align:start position:0% +would you choose to be the base well of +course you would like to choose this + + align:start position:0% +course you would like to choose this + + + align:start position:0% +course you would like to choose this +parallelogram to be the base because it + + align:start position:0% +parallelogram to be the base because it + + + align:start position:0% +parallelogram to be the base because it +contains the base of T if we do so so we + + align:start position:0% +contains the base of T if we do so so we + + + align:start position:0% +contains the base of T if we do so so we +want to choose this pelegrin to be the + + align:start position:0% +want to choose this pelegrin to be the + + + align:start position:0% +want to choose this pelegrin to be the +base then what is the area of this well + + align:start position:0% +base then what is the area of this well + + + align:start position:0% +base then what is the area of this well +it clearly contains two copies of the + + align:start position:0% +it clearly contains two copies of the + + + align:start position:0% +it clearly contains two copies of the +triangle Oh a 1 a 2 + + align:start position:0% +triangle Oh a 1 a 2 + + + align:start position:0% +triangle Oh a 1 a 2 +so the area of the telegram is simply + + align:start position:0% +so the area of the telegram is simply + + + align:start position:0% +so the area of the telegram is simply +equal to twice the area of the triangle + + align:start position:0% +equal to twice the area of the triangle + + + align:start position:0% +equal to twice the area of the triangle +Oh a 1 a 2 then what is the height of of + + align:start position:0% +Oh a 1 a 2 then what is the height of of + + + align:start position:0% +Oh a 1 a 2 then what is the height of of +P again if you choose this face to be + + align:start position:0% +P again if you choose this face to be + + + align:start position:0% +P again if you choose this face to be +the base then a 3 becomes the apex again + + align:start position:0% +the base then a 3 becomes the apex again + + + align:start position:0% +the base then a 3 becomes the apex again +then the height of the parallelepiped is + + align:start position:0% +then the height of the parallelepiped is + + + align:start position:0% +then the height of the parallelepiped is +equal to the distance from a 3 to the + + align:start position:0% +equal to the distance from a 3 to the + + + align:start position:0% +equal to the distance from a 3 to the +base which is the same as the distance + + align:start position:0% +base which is the same as the distance + + + align:start position:0% +base which is the same as the distance +from a 3 to try and go Oh a 1 a 2 so + + align:start position:0% +from a 3 to try and go Oh a 1 a 2 so + + + align:start position:0% +from a 3 to try and go Oh a 1 a 2 so +here the height is also equal to H + + align:start position:0% + + + + align:start position:0% + +now you can compare these two formula + + align:start position:0% +now you can compare these two formula + + + align:start position:0% +now you can compare these two formula +you see that volume of T is simply equal + + align:start position:0% +you see that volume of T is simply equal + + + align:start position:0% +you see that volume of T is simply equal +to one sector of volume of P that's the + + align:start position:0% +to one sector of volume of P that's the + + + align:start position:0% +to one sector of volume of P that's the +connection between the volume of the + + align:start position:0% +connection between the volume of the + + + align:start position:0% +connection between the volume of the +tetrahedron with the volume of the + + align:start position:0% +tetrahedron with the volume of the + + + align:start position:0% +tetrahedron with the volume of the +prototype it in order to compute volume + + align:start position:0% +prototype it in order to compute volume + + + align:start position:0% +prototype it in order to compute volume +of T we only need to compute the volume + + align:start position:0% +of T we only need to compute the volume + + + align:start position:0% +of T we only need to compute the volume +of P now let's compute the volume of + + align:start position:0% +of P now let's compute the volume of + + + align:start position:0% +of P now let's compute the volume of +this parallelepiped we know that it's + + align:start position:0% +this parallelepiped we know that it's + + + align:start position:0% +this parallelepiped we know that it's +related to the determinant of a matrix + + align:start position:0% +related to the determinant of a matrix + + + align:start position:0% +related to the determinant of a matrix +and the row vectors of that matrix are + + align:start position:0% +and the row vectors of that matrix are + + + align:start position:0% +and the row vectors of that matrix are +given by these three edges so because + + align:start position:0% +given by these three edges so because + + + align:start position:0% +given by these three edges so because +all of them start from zero we only need + + align:start position:0% +all of them start from zero we only need + + + align:start position:0% +all of them start from zero we only need +the coordinate of a1 a2 and a3 so here + + align:start position:0% +the coordinate of a1 a2 and a3 so here + + + align:start position:0% +the coordinate of a1 a2 and a3 so here +volume of P is equal to the absolute + + align:start position:0% +volume of P is equal to the absolute + + + align:start position:0% +volume of P is equal to the absolute +value so don't forget the absolute value + + align:start position:0% +value so don't forget the absolute value + + + align:start position:0% +value so don't forget the absolute value +sign absolute value of the determinant + + align:start position:0% +sign absolute value of the determinant + + + align:start position:0% +sign absolute value of the determinant +of a 3x3 matrix so we just need to copy + + align:start position:0% +of a 3x3 matrix so we just need to copy + + + align:start position:0% +of a 3x3 matrix so we just need to copy +the coordinates of the vertices down + + align:start position:0% +the coordinates of the vertices down + + + align:start position:0% +the coordinates of the vertices down +here the first one is 2 2 negative 1 + + align:start position:0% +here the first one is 2 2 negative 1 + + + align:start position:0% +here the first one is 2 2 negative 1 +these two are two coasts next one and a2 + + align:start position:0% +these two are two coasts next one and a2 + + + align:start position:0% +these two are two coasts next one and a2 +is 1 3 0 a 3 is negative 1 1 for the + + align:start position:0% +is 1 3 0 a 3 is negative 1 1 for the + + + align:start position:0% +is 1 3 0 a 3 is negative 1 1 for the +absolute value of this determinant and + + align:start position:0% +absolute value of this determinant and + + + align:start position:0% +absolute value of this determinant and +if you compute this this is a 3x3 matrix + + align:start position:0% +if you compute this this is a 3x3 matrix + + + align:start position:0% +if you compute this this is a 3x3 matrix +the determinant should be easy to + + align:start position:0% +the determinant should be easy to + + + align:start position:0% +the determinant should be easy to +compute and the result should be 12 + + align:start position:0% +compute and the result should be 12 + + + align:start position:0% +compute and the result should be 12 +so that's the volume of P which means + + align:start position:0% +so that's the volume of P which means + + + align:start position:0% +so that's the volume of P which means +the volume of the tetrahedron T is equal + + align:start position:0% +the volume of the tetrahedron T is equal + + + align:start position:0% +the volume of the tetrahedron T is equal +to 12 over 6 which is 2 did you get the + + align:start position:0% +to 12 over 6 which is 2 did you get the + + + align:start position:0% +to 12 over 6 which is 2 did you get the +correct answer okay so in order to + + align:start position:0% +correct answer okay so in order to + + + align:start position:0% +correct answer okay so in order to +compute the volume of T we have related + + align:start position:0% +compute the volume of T we have related + + + align:start position:0% +compute the volume of T we have related +to attach a parallel pipe ap which + + align:start position:0% +to attach a parallel pipe ap which + + + align:start position:0% +to attach a parallel pipe ap which +contains T all right now let's look at + + align:start position:0% +contains T all right now let's look at + + + align:start position:0% +contains T all right now let's look at +the second part the second part says + + align:start position:0% +the second part the second part says + + + align:start position:0% +the second part the second part says +that if I keep a 1 and a 2 and changed + + align:start position:0% +that if I keep a 1 and a 2 and changed + + + align:start position:0% +that if I keep a 1 and a 2 and changed +but I move a 3 to a new point so a 3 is + + align:start position:0% +but I move a 3 to a new point so a 3 is + + + align:start position:0% +but I move a 3 to a new point so a 3 is +going to be moved to a point given by a + + align:start position:0% +going to be moved to a point given by a + + + align:start position:0% +going to be moved to a point given by a +3 Prime and the coordinate is negative + + align:start position:0% +3 Prime and the coordinate is negative + + + align:start position:0% +3 Prime and the coordinate is negative +201 negative 199 and 104 and I'm asking + + align:start position:0% +201 negative 199 and 104 and I'm asking + + + align:start position:0% +201 negative 199 and 104 and I'm asking +you to compute the volume of the new + + align:start position:0% +you to compute the volume of the new + + + align:start position:0% +you to compute the volume of the new +tetrahedron well as you can see this + + align:start position:0% +tetrahedron well as you can see this + + + align:start position:0% +tetrahedron well as you can see this +point seems to be far away from the + + align:start position:0% +point seems to be far away from the + + + align:start position:0% +point seems to be far away from the +origin I am NOT even able to draw this + + align:start position:0% +origin I am NOT even able to draw this + + + align:start position:0% +origin I am NOT even able to draw this +point here but you can imagine as this + + align:start position:0% +point here but you can imagine as this + + + align:start position:0% +point here but you can imagine as this +point goes far away from the origin this + + align:start position:0% +point goes far away from the origin this + + + align:start position:0% +point goes far away from the origin this +spike is going to become more and more + + align:start position:0% +spike is going to become more and more + + + align:start position:0% +spike is going to become more and more +pointy in other words the entire + + align:start position:0% +pointy in other words the entire + + + align:start position:0% +pointy in other words the entire +tetrahedron looks more and more like a + + align:start position:0% +tetrahedron looks more and more like a + + + align:start position:0% +tetrahedron looks more and more like a +needle but nonetheless we can use the + + align:start position:0% +needle but nonetheless we can use the + + + align:start position:0% +needle but nonetheless we can use the +same method to compute it at the volume + + align:start position:0% +same method to compute it at the volume + + + align:start position:0% +same method to compute it at the volume +so we follow the same idea the volume of + + align:start position:0% +so we follow the same idea the volume of + + + align:start position:0% +so we follow the same idea the volume of +T is going to be equal to 1/6 of the + + align:start position:0% +T is going to be equal to 1/6 of the + + + align:start position:0% +T is going to be equal to 1/6 of the +volume of P and in this case that's + + align:start position:0% +volume of P and in this case that's + + + align:start position:0% +volume of P and in this case that's +going to become the absolute value of + + align:start position:0% +going to become the absolute value of + + + align:start position:0% +going to become the absolute value of +the determinant of a 3x3 matrix whose + + align:start position:0% +the determinant of a 3x3 matrix whose + + + align:start position:0% +the determinant of a 3x3 matrix whose +robe actors are given by these three + + align:start position:0% +robe actors are given by these three + + + align:start position:0% +robe actors are given by these three +edges so in this case we again copy down + + align:start position:0% +edges so in this case we again copy down + + + align:start position:0% +edges so in this case we again copy down +the coordinates of three vertices the + + align:start position:0% +the coordinates of three vertices the + + + align:start position:0% +the coordinates of three vertices the +first one is 2 2 negative 1 + + align:start position:0% +first one is 2 2 negative 1 + + + align:start position:0% +first one is 2 2 negative 1 +second one is 1 3 0 the third one should + + align:start position:0% +second one is 1 3 0 the third one should + + + align:start position:0% +second one is 1 3 0 the third one should +become this + + align:start position:0% +become this + + + align:start position:0% +become this +so negative 201 199 104 okay + + align:start position:0% +so negative 201 199 104 okay + + + align:start position:0% +so negative 201 199 104 okay +that should give me the volume of the + + align:start position:0% +that should give me the volume of the + + + align:start position:0% +that should give me the volume of the +neo tetrahedron let me call it t prime + + align:start position:0% +neo tetrahedron let me call it t prime + + + align:start position:0% +neo tetrahedron let me call it t prime +just to differentiate from the previous + + align:start position:0% +just to differentiate from the previous + + + align:start position:0% +just to differentiate from the previous +tetrahedron and of course you can + + align:start position:0% +tetrahedron and of course you can + + + align:start position:0% +tetrahedron and of course you can +compute this determinant explicitly if + + align:start position:0% +compute this determinant explicitly if + + + align:start position:0% +compute this determinant explicitly if +you do so you will see the answer should + + align:start position:0% +you do so you will see the answer should + + + align:start position:0% +you do so you will see the answer should +be 2 again but in fact there's a way + + align:start position:0% +be 2 again but in fact there's a way + + + align:start position:0% +be 2 again but in fact there's a way +that you can just write out the answer + + align:start position:0% +that you can just write out the answer + + + align:start position:0% +that you can just write out the answer +directly without any real computation + + align:start position:0% +directly without any real computation + + + align:start position:0% +directly without any real computation +let's pay attention to the last row in + + align:start position:0% +let's pay attention to the last row in + + + align:start position:0% +let's pay attention to the last row in +other words let's pay attention to this + + align:start position:0% +other words let's pay attention to this + + + align:start position:0% +other words let's pay attention to this +new a3 while a 3 prime what do you + + align:start position:0% +new a3 while a 3 prime what do you + + + align:start position:0% +new a3 while a 3 prime what do you +observe here a 3 prime if you consider + + align:start position:0% +observe here a 3 prime if you consider + + + align:start position:0% +observe here a 3 prime if you consider +the difference between a 3 and a 3 Prime + + align:start position:0% +the difference between a 3 and a 3 Prime + + + align:start position:0% +the difference between a 3 and a 3 Prime +in other words if you consider how much + + align:start position:0% +in other words if you consider how much + + + align:start position:0% +in other words if you consider how much +you have moved your apex you will see + + align:start position:0% +you have moved your apex you will see + + + align:start position:0% +you have moved your apex you will see +that's equal to negative 100 a 1 right + + align:start position:0% +that's equal to negative 100 a 1 right + + + align:start position:0% +that's equal to negative 100 a 1 right +so a 3 is negative 1 1 4 a 3 prime is + + align:start position:0% +so a 3 is negative 1 1 4 a 3 prime is + + + align:start position:0% +so a 3 is negative 1 1 4 a 3 prime is +this that's exactly equal to negative + + align:start position:0% +this that's exactly equal to negative + + + align:start position:0% +this that's exactly equal to negative +100 times a 1 what does that mean well + + align:start position:0% +100 times a 1 what does that mean well + + + align:start position:0% +100 times a 1 what does that mean well +from the point of view of matrix you are + + align:start position:0% +from the point of view of matrix you are + + + align:start position:0% +from the point of view of matrix you are +subtracting from the original 3rd row + + align:start position:0% +subtracting from the original 3rd row + + + align:start position:0% +subtracting from the original 3rd row +100 times the first row but this is this + + align:start position:0% +100 times the first row but this is this + + + align:start position:0% +100 times the first row but this is this +row operation does not change the + + align:start position:0% +row operation does not change the + + + align:start position:0% +row operation does not change the +determinant in other words you know that + + align:start position:0% +determinant in other words you know that + + + align:start position:0% +determinant in other words you know that +this determinant should be the same as + + align:start position:0% +this determinant should be the same as + + + align:start position:0% +this determinant should be the same as +the previous one so you can write out to + + align:start position:0% +the previous one so you can write out to + + + align:start position:0% +the previous one so you can write out to +directly from this picture we can also + + align:start position:0% +directly from this picture we can also + + + align:start position:0% +directly from this picture we can also +see that fact so from this picture we + + align:start position:0% +see that fact so from this picture we + + + align:start position:0% +see that fact so from this picture we +know that this section is saying that I + + align:start position:0% +know that this section is saying that I + + + align:start position:0% +know that this section is saying that I +need to move a 3 in the inverse + + align:start position:0% +need to move a 3 in the inverse + + + align:start position:0% +need to move a 3 in the inverse +direction of a 1 by 100 times a 1 so + + align:start position:0% +direction of a 1 by 100 times a 1 so + + + align:start position:0% +direction of a 1 by 100 times a 1 so +you're moving a 3 + + align:start position:0% +you're moving a 3 + + + align:start position:0% +you're moving a 3 +prologue to a one but it doesn't matter + + align:start position:0% +prologue to a one but it doesn't matter + + + align:start position:0% +prologue to a one but it doesn't matter +how far you've moved your apex you're + + align:start position:0% +how far you've moved your apex you're + + + align:start position:0% +how far you've moved your apex you're +moving in a way that remains parallel to + + align:start position:0% +moving in a way that remains parallel to + + + align:start position:0% +moving in a way that remains parallel to +the base which is saying that this + + align:start position:0% +the base which is saying that this + + + align:start position:0% +the base which is saying that this +movement does not change the height + + align:start position:0% +movement does not change the height + + + align:start position:0% +movement does not change the height +since a1 a2 are fixed your base is fixed + + align:start position:0% +since a1 a2 are fixed your base is fixed + + + align:start position:0% +since a1 a2 are fixed your base is fixed +is fixed and you're not changing the + + align:start position:0% +is fixed and you're not changing the + + + align:start position:0% +is fixed and you're not changing the +height so of course the volume is not + + align:start position:0% +height so of course the volume is not + + + align:start position:0% +height so of course the volume is not +changing that's also a reason another + + align:start position:0% +changing that's also a reason another + + + align:start position:0% +changing that's also a reason another +way to see that the volume of T prime is + + align:start position:0% +way to see that the volume of T prime is + + + align:start position:0% +way to see that the volume of T prime is +simply equal to the volume of T okay + + align:start position:0% +simply equal to the volume of T okay + + + align:start position:0% +simply equal to the volume of T okay +this completes this problem I hope this + + align:start position:0% +this completes this problem I hope this + + + align:start position:0% +this completes this problem I hope this +example is helpful to you and we should + + align:start position:0% +example is helpful to you and we should + + + align:start position:0% +example is helpful to you and we should +keep in mind that the fact that the + + align:start position:0% +keep in mind that the fact that the + + + align:start position:0% +keep in mind that the fact that the +determinant is rated to volume sometimes + + align:start position:0% +determinant is rated to volume sometimes + + + align:start position:0% +determinant is rated to volume sometimes +can become very handy in computing the + + align:start position:0% +can become very handy in computing the + + + align:start position:0% +can become very handy in computing the +volume of certain geometric objects + + align:start position:0% +volume of certain geometric objects + + + align:start position:0% +volume of certain geometric objects +thank you for watching and I'm looking + + align:start position:0% +thank you for watching and I'm looking + + + align:start position:0% +thank you for watching and I'm looking +forward to seeing you soon \ No newline at end of file diff --git a/rzGmSWxhwM8.txt b/rzGmSWxhwM8.txt new file mode 100644 index 0000000000000000000000000000000000000000..5f67767a6f813d957deca76027de15ef46765df2 --- /dev/null +++ b/rzGmSWxhwM8.txt @@ -0,0 +1,379 @@ +The following content is +provided under a Creative + +Commons license. + +Your support will help MIT Open +CourseWare continue to + +offer high-quality educational +resources for free. + +To make a donation or view +additional materials from + +hundreds of MIT courses, visit +MIT OpenCourseWare at + +ocw.mit.edu. + +We, we are solid +state devices. + +This is soft matter. + +My eyes are photo detectors. + +Band gap of about two +electron volts. + +They're just not made +of a compound + +semiconductor inorganic. + +And this motion is just +conformational + +changes in a polymer. + +See it's all chemistry. + +The rest is stamp collecting. + +So the principles that apply to +inanimate objects apply to + +animate objects. + +And the solid-state chemistry +umbrella is very broad. + +If I say solid-state chemistry, +people are apt to + +think of electronic devices, +transistors, what have you. + +But that extends to +the life sciences. + +I mean we, as human beings, +are chemical machines. + +So this is the classical view. + +Electronic structuring informs +bonding but then in 3.091 + +bonding informs atomic +arrangement, which tells you + +everything. + +The shape of all things, it's +all electronic structure. + +There's nothing more. + +The difference is that the +focus in the chemistry + +department, their focus +is the molecule. + +Whereas in 3.091 I like to +think of the focus being + +aggregates of molecules, +namely solids. + +Because engineering systems +are made of solids. + +If you're steeped in chemistry +from high school, you've had + +the AP curriculum, again 3.091 +might be something that is a + +fresh look at chemistry from +a slightly different + +perspective. + +What I wanted to play for you as +you're leaving today is an + +old Beatles song, Lucy in +the Sky with Diamonds. + +Being able to bring in subject +matter, music, art, + +literature, into a chemistry +class and make the connections + +to the world around us, I think +is most important in the + +21st century, when problem +solving even in the technical + +domain is going to require +skills that build bridges to + +the humanities, arts and +social sciences. + +And so I like to think of +3.091 not as a chemistry + +class, but rather a +chemistry-centered class. + +The majority of students taking +3.091 at MIT may never + +take another chemistry class. + +So I ask myself what topics are +critical for someone who + +might major in electrical +engineering? + +Or for someone who might +major in physics? + +Or what's the chemistry that's +critical to an MIT student who + +might major in political +science or economics? + +And that informs my +choice of topics. + +And it turns out that that +doesn't diminish from the + +education of the student who +may choose to major in a + +chemically intensive discipline +such as material + +science, chemical engineering, +or even chemistry itself. + +I don't view the presentation +of the subject matter as a + +linear track, where this +is the beginning + +and this is the end. + +I view it more along the +lines of a spiral. + +And so the first time you +encounter a certain concept + +it's at a rather superficial +introductory level. + +And then at some point later +in the semester you spiral + +back and see it again. + +And then maybe there's a little +more context and a + +little more intensity. + +Maybe there's a little +more mathematics + +associated with it. + +And then you'll see it +applied later again. + +And through that revisiting-- + +repetition by design-- + +I think that key concepts +get driven home. + +Some people are shocked that +I stand in front of a chalk + +board and I write on it and I +believe that that's still a + +valid means of teaching. + +For the first-time learner +I think it's important to + +activate all of the +learning channels. + +The act of drawing +and inspiring + +them to draw is important. + +And maybe the person at home +ought to put themselves in a + +chair in the auditorium and be +taking notes as though they + +are attending the lecture. + +Watching those videos, +especially for someone that + +has had a fair bit of high +school chemistry, you're going + +to hear a lot of the same things +but maybe coming at you + +at a slightly elevated level. + +But not so elevated that +you won't follow it. + +And I think that's good for a +high school student to be + +talked to at a higher level. + +I think the videos also have +utility for people that are + +interested in specific topics. + +I mean for example, if somebody +needs to know + +something about x-rays, or the +use of x-rays, dropping in to + +that three-lecture sequence on +x-rays could be quite useful. + +I think it's possible to +sample with a goal of + +mastering a particular +concept. + +So clearly for the learner out +in the World Wide Web, going + +to recitation and interacting +with a recitation instructor + +is not practical. + +So in lieu of the recitation +section OCW has created these + +help session videos. + +We actually hired some +recitation instructors from + +the fall of 2009 and asked +them to work through some + +sample problems and what you see +in the help session video + +is essentially what would +have happened in + +a recitation section. + +I issue the homework questions +with model solutions at the + +beginning of the unit. + +So the homework becomes +a study aid. + +And I recommend to students +that they try the homework + +problems without referring to +the answer key initially. + +And to turn to the answer key +when they reach an impediment. + +What's the message of 3.091 +for the man on the street? + +An understanding of those +relationships. + +Electronic structure +to bonding. + +Bonding to atomic arrangement. + +Atomic arrangement +to properties. + +Is the key to understanding +the world around us. + +And in particular it's the +key to fueling invention. + +And I believe in practice very +much and in the application of + +science in service +for humanity. + +Why do we worry about designing +a car that's a + +zero-emission vehicle, as +if to do no harm to the + +environment? + +Why don't we go even further and +say, what about a car that + +purifies the air as it +drives down the road? + +So that the air in the wake of +the car is cleaner than the + +air in front of the car? + +And I'm finding that +increasingly that's a message + +that resonates with +the students. + +They want to take the tools +of technical analytically + +centered education and +put them to work to + +solve societal problems. \ No newline at end of file diff --git a/s98jdWi2kEs.txt b/s98jdWi2kEs.txt new file mode 100644 index 0000000000000000000000000000000000000000..0ee9961e4bd66e4a7dbb756c902596be6025ea28 --- /dev/null +++ b/s98jdWi2kEs.txt @@ -0,0 +1,3931 @@ +The following content is +provided under a Creative + +Commons license. + +Your support will help MIT +OpenCourseWare continue to + +offer high-quality educational +resources for free. + +To make a donation or view +additional materials from + +hundreds of MIT courses, visit +MIT OpenCourseWare at + +ocw.mit.edu. + +PROFESSOR: OK, so let's +get started. + +I want to talk mostly about +countable state Markov chains + +today, which is the new topic +we started on Wednesday. + +I want to talk just a little bit +about the strong law proof + +that was in the third +problem of the quiz. + +I'm not doing that because +none of you understood + +anything about it. + +I'm doing it because all of you +understood more about it + +than I thought you would. + +And in fact, I've always avoided +saying too much about + +this proof because I thought +everybody was tuning them out. + +And for the class here, it looks +like a lot of you have + +tried seriously to understand +these things. + +So I thought I would explain +that one part of the quiz in + +detail so that you'd see the +parts you're missing, and so + +that [INAUDIBLE] all these other +proofs that we have, + +talking about the strong law +and the strong law for + +renewals, and putting them +together and all of these + +things, all of them are +essentially the same. + +And it's just a matter +of figuring out + +how things fit together. + +So I wanted to talk about that +because it's clear that most + +of you understand enough about +it that it makes sense. + +The situation in the quiz, which +is very close to the + +usual queuing situation and +little theorem type things, + +there's a sequence +of Y sub i's. + +They're IID. + +There's the service times for +G/G infinity queue, and n of + +t, which is a renewal +process for the + +arrivals to the process. + +We have arrivals coming in +according to this renewal + +process, which means the +[INAUDIBLE] arrival times, X + +sub i, were IID. + +And we want to put those +two things together. + +And we want to find out +what this limit is. + +If it's a limit, show +that it's a limit. + +And hopefully show that it's +a limit with probability 1. + +And I think a large number of +you basically realize that + +this argument consisted +of a bunch of steps. + +Some people with more +detail than others. + +But the first step, which we do +in all of these arguments, + +is to divide and multiply +by n of t of omega. + +So we're starting out, looking +at some particular sample + +path, and start out by +multiplying and dividing by n + +of t of omega. + +The next thing is to claim that +the limit of this times + +this is equal to the limit of +this times the limit of this. + +Almost no one recognized that as +a real problem, and that is + +a real problem. + +It's probably the least +obvious thing + +in this whole problem. + +I'm not saying you shouldn't +have done that, because I've + +been doing that in all +the proofs I've been + +giving you all along. + +It is sort of obvious +that that works. + +And when you're constructing a +proof, especially in a quiz + +when you don't have much time, +things which are almost + +obvious or which look obvious, +you should just go ahead and + +assume them and come back later +when you have time to + +see whether that really +makes sense. + +That's the way you +do research also. + +You don't do research by +painstakingly establishing + +every point in some +linear path. + +What you do is you carelessly +as you can and with as much + +insight as you can, you jump +all the way to the end, you + +see where you're trying to go, +you see how to get there, and + +then you come back and you try +to figure out what each + +of the steps are. + +So this is certainly a very +reasonable way of solving this + +problem, because it looks like +this limit should be equal to + +this limit times this limit. + +The next step in the argument is +to claim that this sum, up + +to N of t of omega, over +N of t of omega, as + +t approaches infinity-- + +the argument is that t +approaches infinity-- + +this N of t of omega goes +through, one by one, a + +sequence, 1, 2, 3, 4, +5, and so forth. + +So this limit is equal +to that limit. + +I've never been able to figure +out whether that's obvious or + +not obvious. + +It is just on the borderline +between what's obvious and not + +obvious, so I'm gonna +prove it to you. + +And then the next step is to see +that N of t of omega over + +t is equal to 1/X-bar +with probability 1. + +And this limit is equal to +Y-bar with probability 1. + +The first argument, this equal +to 1/X-bar is because of the + +strong law with renewals. + +And this one over here is +because of the strong law of + +large numbers. + +And most of you managed +to get this. + +And the whole argument assumes +that X-bar is less than + +infinity, and Y-bar is +less than infinity. + +Now, how do you go back and +actually see that this + +actually makes sense? + +And that's what I +want to do next. + +And if you look at this, you +can't do it by starting here + +and working your way down to +there, because there's no way + +you're going to argue that this +limit is equal to this + +product of limit unless you know +something about this and + +you know something about this. + +So you really have to establish +that these things + +have limits first before +you can go back + +and establish this. + +In the same way, you have to +know something about this + +before you can establish this. + +So what you have to do way after +you've managed to have + +the insight to jump the whole +way through this thing, is to + +go back and argue each of the +points, but argue them in + +reverse order. + +And that's very often the way +you do research, and it's + +certainly the way +you do quizzes. + +So let's see where those +arguments were. + +Start out by letting A1 be the +set of omega for which this + +limit here, N of t of omega over +t, is equal to 1/X-bar. + +By the strong law for renewal +processes, the probability of + +A1 equals 1. + +This is stating this in a little +cleaner way, I think, + +than we stated the strong law +of renewals originally, + +because we started out by +tumbling together this + +statement and this statement. + +I think it's cleaner to say, +start out, there's a set of + +omega 1 for which this +limit exists. + +And what the strong law says is +that that set of omega has + +probability 1. + +And now we have some terminology +for A1, what it + +actually means. + +It is the set of omega +for which this works. + +You never have it working +for all omega, + +only for some omega. + +Then the next step, let A2 be +the set of omega for which the + +limit is n goes to infinity of +1/n times the sum of Y sub i + +of omega, is equal to Y-bar. + +By the strong law of large +numbers, the probability of A2 + +is equal to 1. + +So now we've established there's +an A1, there's an A2. + +Each of them have +probability 1. + +On A1, one limit exists. + +On A2, the other limit exists. + +And we have two sets, both +at probability 1. + +What's the probability of the +intersection of them? + +It has to be 1 also. + +So with that, you know that +equation three is equal to + +equation four for omega +in the sets, A1, A2. + +And also, you know that +the probability of A1, + +A2 is equal to 1. + +So we've established this part +of the argument down here. + +Now we want to go up and +establish this part of the + +argument, which as I said, I +can't convince myself that + +it's necessary or +not necessary. + +But since I can't convince +myself, I thought, in trying + +to make up solutions for the +quiz, I ought to actually + +write a proof of it. + +And I want to show you what the +proof is so that, if it's + +not obvious to you, you'll know +exactly how to do it. + +And if it is obvious, you can +maybe sort out exactly why + +it's obvious. + +So this is an epsilon delta +kind of argument. + +We assume that omega is in A2. + +That's the set for which +the strong law of + +large numbers holds. + +There exists some integer, n, +which is a function of both + +epsilon and omega. + +This is the funny thing +about all of + +these strong law arguments. + +In almost all of them, +you're dealing with + +individual sample paths. + +When you start saying something +exists as a limit, + +you're not saying that it exists +as a limit for the + +random variables. + +You're saying it exists +as a limit for a + +set of sample paths. + +And therefore, this epsilon here +that you're gonna choose, + +you need some integer there, +such that this minus this is + +less than epsilon. + +I think I'm going to have +to give up on this. + +These things run out of +batteries too quickly. + +So we have that this difference +here must be less + +than epsilon if n is bigger than +that m of epsilon omega. + +That's simply what +a limit means. + +That's the definition +of a limit. + +The only way to define a limit +sensibly is to say, for all + +epsilon greater than 0, no +matter how small the epsilon + +is, you can always find an +n big enough that this + +difference here is less +than epsilon. + +Then if omega is also in A1, the +limit of N of t of omega + +has to be equal to infinity. + +If you want to, you can just +say, we proved in class that + +the limit of t of omega is +equal to infinity with + +probability 1, and introduce +another set, A3. + +You want to do a +probability 1. + +But let's do it this way. + +And then there has to be a t, +which is also a function of + +epsilon and omega, such +that N of t and + +omega is greater than-- + +that's an integer, by the way. + +That's greater than or equal to +m of epsilon of omega for + +all t, which is greater +than or equal to t + +of epsilon of omega. + +That says that this difference +here is less than omega. + +And that's true for all epsilon +greater than 0. + +And that says that, in fact, +this limit has to exist. + +This limit over here is equal +to Y-bar with probability 1. + +So that's what we were trying to +prove here, that this limit + +is the same as this limit. + +So we found out what +this limit is. + +We found out that it exists with +probability 1, namely on + +the set A2. + +This is equal to this, not +necessarily on A2, + +but on A1 and A2. + +So we got into there. + +Now how do we get the fact that +this limit times this + +limit is equal to the limit +of [? these. ?] + +Now we have a chance of +proceeding, because we've + +actually shown that this limit +exists on some set with + +probability 1, this limit +exists on some set with + +probability 1. + +So we can look at that set and +say, for omega in that set, + +this limit exists and +this limit exists. + +Those limits are non-0 and +they're non-infinite. + +The important thing is that +they're non-infinite. + +And we move on from there, +and to do that carefully. + +And again, I'm not suggesting +that I expect any of you to do + +this on the quiz. + +I would have been amazed +if you had. + +It took me quite a while to sort +it out, because all these + +things are tangled together. + +Where am I? + +I want to be in the +next slide. + +Ah, there we go. + +Finally, we can interchange the +limit of a product of two + +functions-- + +say, f of t, g of t-- + +with the product +of the limits. + +Can we do that? + +If the two functions each have +finite limits, as the + +functions of interests do for +omega in A1, A2, then the + +answer is yes. + +And if you look at any book +on analysis, I'm sure that + +theorem is somewhere in the +first couple of chapters. + +But anyway, if you're the kind +of person like I am who would + +rather sort something out for +yourself rather than look it + +up, there's a trick involved +in doing it. + +It's this equality right here. + +f of t times g of t minus ab. + +What you want to do is somehow +make that look like f of t + +minus a, which you have +some control over, and + +g of t minus b. + +So the identity is this is equal +to f of t minus a times + +g of t minus b-- + +we have control over that-- + +plus a times g of t minus b, +plus b times f of t minus a. + +And you multiply and add all +those things together and you + +see that that is just +an identity. + +And therefore the magnitude of +f of t times g of t minus ab + +is less than or equal to this. + +And then you go through all the +epsilon delta stuff again. + +For any epsilon greater than +0, you choose a t such that + +this is less than or equal +to epsilon for t + +greater than the t epsilon. + +This is less than or equal to +epsilon for t greater than or + +equal to t epsilon. + +And then this difference here +is less than or equal to + +epsilon squared plus this. + +And with a little extra fiddling +around, that shows + +you have that f of t, g of t +minus ab approaches 0 as t + +gets large. + +So that's the whole thing. + +Now, let me reemphasize +again, I did not + +expect you to do that. + +I did not expect you to know how +to do analysis arguments + +like that, because +analysis is not a + +prerequisite for the course. + +I do want to show you that the +kinds of things we've been + +doing are not, in fact, +impossible. + +If you trace them out from +beginning to end and put in + +every little detail in them. + +If you have to go through +these kinds of arguments + +again, you will in fact know +how to make it precise and + +know how to put all +those details in. + +Let's go back to countable +state Markov chains. + +As we've said, two states are +in the same class as they + +communicate. + +It's the same definition as +for finite state chains. + +They communicate if there's some +path by which you can get + +from i to j, and there's some +path from which you can get + +from j to i. + +And you can't get there in one +step only, but you can get + +there in some finite +number of steps. + +So that's the definition of +two states communicating. + +The theorem that we sort of +proved last time is that all + +states in the same class are + +recurrent or all are transient. + +That's the same as the theorem +we have for finite state + +Markov chains. + +It's just a little hard +to establish here. + +The argument is that you assume +that j is recurrent. + +If j is recurrent, +then the sum has + +to be equal to infinity. + +How do you interpret +that sum there? + +What is it? + +P sub jj, super n, is the +probability that you will be + +in state j at time n given +that you're in + +state j at time 0. + +So what we're doing is we're +starting out in time 0. + +This quantity here is the +probability that we'll be in + +state j at time n. + +Since you either are or you're +not, since this is also equal + +to the expected value of state +j at time n, given + +state j at time 0. + +So when you add all these up, +you're adding expectations. + +So this quantity here is simply +the expected number of + +recurrences to state j from time +1 up to time infinity. + +And that number of recurrences +is equal to infinity. + +You remember we argued last time +that the probability of + +one recurrence had to be equal +to 1 if it was recurrent. + +If you got back to j once in +finite time, you're going to + +get back again in a +finite time again. + +You're going to get back +again in finite time. + +It might take a very, very long +time, but it's finite, + +and you have an infinite number +of returns as time goes + +to infinity. + +So that is the consequence +of j being recurrent. + +For any i such that j and i +communicate, there's some path + +at some length m such that the +probability of going from + +state i to state j in m steps +is greater than 0. + +That's by meaning +of communicate. + +And there's some m and +some pji of l. + +Oh, for [? some m. ?] + +And there's some way of getting +back from j to i. + +So what you're doing is going +from state i to state j, and + +there is some path +for doing that. + +You're wobbling around, +returning to state j, + +returning to state j, +maybe returning to + +state i along the way. + +That's part of it. + +And eventually there's +some path for going + +from j back to i again. + +So this sum here is greater +than or equal. + +And now all I'm doing is summing +up the paths which in + +m steps go from i to j, and +those paths which in the final + +l steps go from j back to i. + +And they do whatever they +want to in between. + +So I'm summing over the number +of times they are in between. + +And this sum here is +summing over pjjk. + +And that sum is infinite, +so this sum is infinite. + +So that shows that if j is +recurrent, then i is recurrent + +also for any i in +the same class. + +And you can do the same thing +reversing i and j, obviously. + +And if that's true for all +classes that are very + +recurrent, all law classes that +are transient have to be + +in the same class also, because +a state is either + +transient or it's recurrent. + +If a state j is recurrent, +then the + +recurrence time, T sub jj. + +When you read this chapter or +read my notes, I apologize + +because there's a huge +confusion here. + +And the confusion comes from +the fact that there's an + +extraordinary amount +of notation here. + +We're dealing with all the +notation of finite-state + +Markov chains. + +We're dealing with all the +notation of renewal processes. + +And we're jumping back and forth +between theorems for one + +and theorems for the other. + +And then we're inventing +a lot of new notation. + +And I have to rewrite +that section. + +But anyway, the results are all +correct as far as I know. + +I mean, all of you can remember +notation much better + +than I can. + +So if I can remember this +notation, you can also. + +Let me put it that way. + +So I can't feel too +sorry for you. + +I want to rewrite it because I'm +feeling sorry for myself + +after every year I go through +this and try to re-understand + +it again, and I find it +very hard to do it. + +So I'm going to rewrite +it and get rid of + +some of that notation. + +We've already seen that if you +have a chain like this, which + +is simply the Markov chain +corresponding to Bernoulli + +trials, if it's Bernoulli trials +with p equals 1/2, you + +move up a probability +1/2, you move down + +with probability 1/2. + +As we said, you eventually +disperse. + +And as you disperse, the +probability of being in any + +one of these states goes to 0. + +And what that means is that the +individual probabilities + +of the states is going to 0. + +You can also see, not so easily, +that you're eventually + +going to return to each state +with probability 1. + +And I'm sorry I didn't give +that definition first. + +We gave it last time. + +If the expected value of the +renewal time is less than + +infinity, then j is positive +recurrent. + +If T sub jj, the recurrence +time, is a random variable but + +it has infinite expectation, +then j is not recurrent. + +And finally, if none of those +things happen, j is transient. + +So that we went through +last time. + +And for p equals 1/2, and in +both of these situations, the + +probability of being in any +state is going to 0. + +The expected time of returning +is going to infinity. + +But with probability 1, you +will return eventually. + +So in both of these cases, these +are both examples of no + +recurrence. + +Let's say more about positive +recurrence and no recurrence. + +Suppose, first, that i and j +are both recurrent and they + +both communicate with +each other. + +In other words, there's a path +from i to j, there's a path + +from j to i. + +And I want to look at +the renewal process + +of returns to j. + +You've sorted out by now, I +think, that recurrence means + +exactly what you +think it means. + +A recurrence means, starting +from a state j, there's a + +recurrence to j if eventually +you come back to j. + +And this random variable, the +recurrence of random variable, + +is the amount of time it takes +you to get back to j once + +you've been in j. + +That's a random variable. + +So let's look at the renewal +process, starting in j, of + +returning to j eventually. + +This is one of the +things that makes + +this whole study awkward. + +We have renewal processes when +we start at j and we bob back + +to j at various periods +of time. + +If we start in i and we're +interested in returns to j, + +then we have something called +a delayed renewal process. + +All the theorems about +renewals apply there. + +It's a little harder to +see what's going on. + +It's in the end of +chapter four. + +You should have read it, +at least quickly. + +But we're going to avoid those +theorems and instead go + +directly using the theorems +of renewal processes. + +But there's still places where +the transitions are awkward. + +So I can warn you about that. + +But the renewal reward theorem, +if I look at this + +renewal process, I get a +renewal every time I + +return to state j. + +But in that renewal process of +returns to state j, what I'm + +really interested in is returns +to state i, because + +what I'm trying to do here is +relate how often do you go to + +state i with how often +do you go to state j? + +So we have a little bit of a +symmetry in it, because we're + +starting in state j, +because that gives + +us a renewal process. + +But now we have this renewal +reward process, where we give + +ourselves a reward of 1 every +time we hit state i. + +And we have a renewal every +time we hit state j. + +So how does that renewal +process work? + +Well, it's a renewal process +just like every other one + +we've studied. + +It has this peculiar feature +here that is a discrete time + +renewal process. + +And with discrete time renewal +processes, as we've seen, you + +can save yourself a lot of +aggravation by only looking at + +these discrete times. + +Namely, you only look +at integer times. + +And now when you only look +at integer times-- + +well, whether you look at +integer times or not-- + +this is the fundamental theorem +of renewal rewards. + +If you look at the limit as t +goes to infinity, there's the + +integral of the rewards +you pick up. + +For this discrete case, this +is just a summation of the + +rewards that you get. + +This summation here by the +theorem is equal to the + +expected number of rewards +within one renewal period. + +Namely, this is the expected +number of recurrences of state + +i per state j. + +So in between each occurrence +of state j, what's the + +expected number of +i's that I hit? + +And that's the number +that it is. + +We don't know what that number +is, but we could calculate it + +if we wanted to. + +It's not a limit of anything. + +Well, it's a sort of a limit, +but not very much of a limit + +that's well defined. + +And the theorem says that this +integral is equal to that + +expected value divided by +the expected recurrence + +time of T sub jj. + +Now, we argue that this is, +in fact, the number of + +occurrences of state i. + +So it's in the limit. + +It's 1 over the expected +value of the recurrence + +time to state i. + +So what this says is the 1 over +the recurrence time to + +state i is equal to the expected +number of recurrences + +to state i per state j divided +by the expected + +time in state j. + +If you think about that for a +minute, it's something which + +is intuitively obvious. + +I mean, you look at this long +sequences of things. + +You keep hitting j's every +once in a while. + +And then what you do, +is you count all of + +the i's that occur. + +So now looking at it this way, +you're going to count the + +number of i's that occur +in between each j. + +You can't have a simultaneous +i and j. + +The state is o or j. + +So for each recurrence period, +you count the number of i's + +that occur. + +And what this is then saying, +is the expected time between + +i's is equal to the expected +time between j's divided by-- + +if I turn this equation upside +down, the expected time + +between i's is equal to the +expected time between j's + +divided by the expected +number of i's per j. + +What else would you expect? + +It has to be that way, right? + +But this says that it +indeed, is that way. + +Mathematics is sometimes +confusing with countable-state + +chains as we've seen. + +OK, so the theorem then says for +i and j recurrent, either + +both are positive-recurrent or +both are null-recurrent. + +So this is adding to the +theorem we had earlier. + +The theorem we had earlier says +that all states within a + +class are either recurrent +or they're transient. + +This now divides the ones that +are recurrent into two + +subsets, those that are +null-recurrent and those that + +are positive-recurrent. + +It says that for states within +a class, either all of them + +are recurrent or all +of them are-- + +all of them are +positive-recurrent or all of + +them are null-recurrent. + +And this theorem shows it +because this theorem says + +there has to be an expected +number of occurrences of state + +i between each occurrence +of state j. + +Why is that? + +Because there has to be +a path from i to j. + +And there has to be a path that +doesn't go through i. + +Because if you have a path from +i that goes back to i and + +then off to j, there's also +this path from i to j. + +So there's a path from i to j. + +There's a path from j to i that +does not go through i. + +That has positive probability +because paths are only defined + +over transitions with positive +probability. + +So this quantity is always +positive if you're talking + +about two states in +the same class. + +So what this relationship says, +along with the fact that + +it's a very nice and convenient +relationship-- + +I almost put it in the +quiz for finite + +state and Markov chains. + +And you cam be happy I didn't, +because proving it takes a + +little more agility than +what one might + +expect at this point. + +The theorem then says that if i +and j are recurrent, either + +both are positive-recurrent or +both are null-recurrent, what + +the overall theorem then says +is that for every class of + +states, either all of them are +transient, all of them are + +null-recurrent, or all of them +are positive-recurrent. + +And that's sort of a convenient +relationship. + +You can't have some states +that you never get to. + +Or you only get to with an +infinite recurrence time in a + +class and others that you keep +coming back to all the time. + +If there's a path from one to +the other, then they have to + +work the same way. + +This sort of makes it +obvious why that is. + +And this is too sensitive. + +OK. + +OK , so now we want to look +at steady state for + +positive-recurrent chain. + +Do you remember that when we +looked at finite state in + +Markov chains, we did all this +classification stuff, and then + +we went into all this +matrix stuff? + +And the outcome of the matrix +stuff, the most important + +things, were that there +is a steady state. + +There's always a set of +probabilities such that if you + +start the chain in those +probabilities, the chain stays + +in those probabilities. + +There's always a set of pi sub +i's, which are probabilities. + +They all sum to 1. + +They're all non-negative. + +And each of them satisfy the +relationship, the probability + +that you're in state j at time +t is equal to the probability + +that you're in state i at +time t minus 1 times the + +probability of going +from state i to j. + +This is completely familiar +from finite-state chains. + +And this is exactly +the same for + +countable-state and Markov chains. + +The only question is, it's now +not at all sure that that + +equation has a solution +anymore. + +And unfortunately, you can't +use matrix theory to prove + +that it has a solution. + +So we have to find some +other way of doing it. + +So we look in our toolbox, +which we developed + +throughout the term. + +And there's only one obvious +thing to try, and + +it's renewal theory. + +So we use renewal theory. + +We then want to have one other +definition, which you'll see + +throughout the rest of the term +and every time you start + +reading about Markov chains. + +When you read about Markov +chains in queuing kinds of + +situations, which are the kinds +of things that occur all + +over the place, almost all of +those Markov chains are + +countable-state Markov chains. + +And therefore, you need a +convenient word to talk about + +a class of states where all of +the states in that class + +communicate with each other. + +And irreducible is the +definition that we use. + +An irreducible Markov chain is +a Markov chain in which all + +pairs of states communicate +with each other. + +And before, when we were talking +about finite-state + +Markov chains, if all states +communicated with each other, + +then they were are recurrent. + +You had a recurrent Markov +chain, end of story. + +Now we've seen that you can have +a Markov chain where all + +the states communicate +with each other. + +We just had these +two examples-- + +these two examples here +where they all + +communicate with each other. + +But depending on what p and q +are, they're either transition + +transient, or they're +positive-recurrent, or they're + +null-recurrent. + +The first one can't even be +positive-recurrent, but it can + +be recurrent. + +And the bottom one can also +be positive-recurrent. + +So any Markov chain where all +the states communicate with + +each other-- + +there's a path from everything +to everything else-- + +which is the usual situation, +is called an irreducible + +Markov chain. + +An irreducible can now be +positive-recurrent, + +null-recurrent, or transient. + +All the states in an irreducible +Markov chain have + +to be transient, or all +of them have to be + +positive-recurrent, or all +of them have to be + +null-recurrent. + +You can't share these +qualities over + +an irreducible chain. + +That's what this last +theorem just said. + +OK, so if a steady +state exists-- + +namely if the solution to those +equations exist, and if + +the probability that X sub 0 +equals i is equal to pi i. + +And incidentally, in the version +that got handed out, + +that equation there was +a little bit garbled. + +That one. + +Said the probability that X sub +0 was equal to pi i, which + +doesn't make any sense. + +If a steady-state exists +and you start out in + +steady-state-- + +namely, the starting state X +sub 0 is in state i with + +probability pi sub i by for +every i, this is the same + +trick we played for + +finite-state and Markov chains. + +As we go through this, I will +try to explain what's the same + +and what's different. + +And this is completely +the same. + +So there's nothing new here. + +Then, this situation of being in +steady-state persists from + +one unit of time to the next. + +Namely, if you start out in +steady-state, then the + +probability that X sub 1 is +equal to j is equal to the sum + +over i of pi sub i. + +That's the probability that +X sub 0 is equal to i. + +Times P sub i j, which by the +steady-state equations, is + +equal to pi sub j. + +So you start out in +steady-state. + +After one transition, you're +in steady-state again. + +You're in steady-state +at time 1. + +Guess what, you're +in state time 2. + +You're in steady-state again. + +And you stay in steady-state +forever. + +So when you iterate, the +probability that you're in + +state j at time X sub n is +equal to pi sub j also. + +This is assuming that you +started out in steady-state. + +So again, we need some +new notation here. + +Let's let N sub j of tilde be +the number of visits to j in + +the period 0 to t starting +in steady-state. + +Namely, if you start in state j, +we get a renewal process to + +talk about the returns +to state j. + +If we start in steady-state, +then this first return to + +state j is going to have a +different set of probabilities + +than all subsequent returns +to state j. + +So N sub j of t, tilde is now +not a renewal process, but a + +delayed renewal process. + +So we have to deal with it +a little bit differently. + +But it's a very nice thing +because for all t, the + +expected number of returns to +state j over t transitions is + +equal to n times pi sub j. + +Pi sub j is the probability that +you will be in state j at + +any time n. + +And it stays the same +for every n. + +So if we look at the expected +number of times we hit state + +j, it's exactly equal +to n times pi sub j. + +And again, here's this +awkward thing about + +renewals and Markov. + +Yes? + +AUDIENCE: So is that sort of +like an ensemble average-- + +PROFESSOR: Yes. + +AUDIENCE: Or is the time +average [INAUDIBLE]? + +PROFESSOR: Well, it's an +ensemble average and it's a + +time average. + +But the thing we're working +with here is the + +fact there's a time-- + +is the fact that it's an +ensemble average, yes. + +But it's convenient +because it's an + +exact ensemble average. + +Usually, with renewal processes, +things are ugly + +until you start getting +into the limit zone. + +Here, everything is nice +and clean all the time. + +So we start out in steady-state +and we get this + +beautiful result. + +It's starting in steady-state. + +The expected number of visit +to state j by time n-- + +oh, this is interesting. + +That t there should +be n obviously. + +Well, since we have t's +everywhere else, that n there + +should probably be t also. + +So you can fix it whichever +way you want. + +n's and t's are the same. + +I mean, for the purposes of this +lecture, let all t's be + +n's and let all n's be t's. + +This works for some things. + +This starts in steady state, +stays in steady state. + +It doesn't work for renewals +because it's a delayed renewal + +process, so you can't talk +about a renewal process + +starting in state j, because you +don't know that it starts + +in state j. + +So sometimes we want +to deal with this. + +Sometimes we want to +deal with this. + +This is the number of returns +to t starting in state j. + +This is the number of returns +to state j over 0 to t if we + +start in steady-state. + +Here's a useful hack, which you +can use a lot of the time. + +Look at what N sub +i j of t is. + +It's the number of times +you hit state j + +starting in state i. + +So let's look at it as you go +for while, you hit state j for + +the first time. + +After hitting state j for the +first time, you then go + +through a number of repetitions +of state j. + +But after that first time you +hit state j, you have a + +renewal process starting then. + +In other words, you have a +delayed renewal process up to + +the first renewal. + +After that, you have +all the statistics + +of a renewal process. + +So the idea then is N +sub i j of t is 1. + +Counts 1 for the first visit +to j, if there are any. + +Plus, N sub i j of t minus +1 for all the subsequent + +recurrences from j to j. + +Thus, when you look at the +expected values of this, the + +expected value of N sub i j of +t is less than or equal to 1 + +for this first recurrence, for +this first visit, plus the + +expected value of N sub j j of +some number smaller than t. + +But N sub j j of +t grows with t. + +It's a number of visits +over some interval. + +And as the interval gets bigger +and bigger, the number + +of visits can't shrink. + +So you just put the t there +to make it an upper bound. + +And then, when you look at +starting in steady-state, what + +you get is the sum overall +starting states pi sub i of + +the expected value of +N sub i j of t. + +And this is less than or equal +to 1 plus the expected value + +of N sub j j of t also. + +So this says you can always get +from N tilde of t to N sub + +j j of t, by just giving +up this term 1 + +here as an upper bound. + +If you don't like that proof-- + +and it's not really a proof. + +If you try to make it a proof, +it gets kind of ugly. + +It's part of the proof of +theorem 4 in the text, which + +is even more ugly. + +Because it's mathematically +clean with equations, but you + +don't get any idea of why it's +true from looking at it. + +This you know why it's true from +looking at it, but you're + +not quite sure that it satisfies +the equations that + +you would like. + +I am trying to move you from +being totally dependent on + +equations to being more +dependent on ideas like this, + +where you can see +what's going on. + +But I'm also urging you, after +you see what's going on, to + +have a way to put the equations +in to see that + +you're absolutely +right with it. + +OK, now, we come to the major +theorem of countable-state and + +Markov chains. + +It's sort of the crucial +thing that everything + +else is based on. + +I mean, everything beyond +what we've already done. + +For any irreducible +Markov chain-- + +in other words, for any Markov +chain where all the states + +communicate with each other, +the steady-state equations + +have a solution if and only +if the states are + +positive-recurrent. + +Now, remember, either all the +states are positive-recurrent + +or none of them are. + +So there's nothing +confusing there. + +If all the states are +positive-recurrent, then there + +is a steady-state solution. + +There is a solution to +those equations. + +And if the set of states are +transient, or null-recurrent, + +then there isn't a solution +to all those equations. + +If a solution exists, then the +probability, the steady-state + +probability is state i is 1 over +the main recurrence time + +to state i. + +This is a relationship that we +established by using renewal + +theory for finite-state +and Markov chains. + +We're just coming +back to it here. + +One thing which is important +here is that pi sub i is + +greater than 0 for all i. + +This is a property we +had for finite-state + +Markov chains also. + +But it's a good deal more +surprising here. + +When you have a countable number +of states, saying that + +every one of them has a positive +probability is-- + +I don't think it's entirely +intuitive. + +If you think about it +for a long time, + +it's sort of intuitive. + +But it's the kind of intuitive +thing that really pushes your + +intuition into understanding +what's going on. + +So let's give a Pf of this, +of the only if part. + +And I will warn you +about reading the + +proof in the notes. + +It's ugly because it just goes +through a bunch of logical + +relationships and equations. + +You have no idea of where +it's going or why. + +And finally, at the +end it says, QED. + +I went through it. + +It's correct. + +But damned if I know why. + +And so, anyway, that has +to be rewritten. + +But, anyway here's the Pf. + +Start out by assuming that the +steady-state equations exist. + +We want to show +positive-recurrence. + +Pick any j and any t. + +Pick any state and any time. + +pi sub j is equal to the +expected value of N sub j + +tilde of t. + +That we chose for any +Markov chain at all. + +If you start out in +steady-state, you stay in + +steady-state. + +So under the assumption that +we're in steady-state-- + +under the assumption that we +start out in steady-state, we + +stay in steady-state. + +This pi sub j times t has to be +the expected value of the + +number of recurrences to state +j over t time units. + +And what we showed on +the last slide-- + +you must have realized I was +doing this for some reason. + +This is less than or equal to 1 +plus the expected recurrence + +time of state j. + +So pi sub j is less than or +equal to 1 over t times this + +expected recurrence +time for state j. + +And if we go to the limit as t +goes to infinity, this 1 over + +t dribbles away to +nothingness. + +So this is less than or equal to +the limit of expected value + +of N sub j j of t over t. + +What is that? + +That's the expected number, +long-term rate of + +visits to state j. + +It's what we've shown as equal +to 1 over the expected renewal + +time of state j. + +Now, if the sum of the pi sub +j's is equal to 1, remember + +what happens when you sum a +countable set of numbers. + +If all of them are 0, then no +matter how many of them you + +sum, you have 0. + +And when you go to the limit, +you still have 0. + +So when you sum a set of +countable set of non-negative + +numbers, you have +to have a limit. + +Because it's non-decreasing. + +And that sum is equal to 1. + +Then somewhere along the line, +you've got to find the + +positive probability. + +One of the [INAUDIBLE] + +has to be positive. + +I mean, this is almost an +amusing proof because you work + +so hard to prove that one +of them is positive. + +And then, almost for free, you +get the fact that all of them + +have to be positive. + +So some pi j is greater +than 0. + +If pi j is less than or equal +to this, thus the limit as t + +approaches infinity of the +expected value of N sub j j of + +t over t is greater than 0 for +that j, which says j has to be + +positive-recurrent. + +Which says all the states have +to be positive-recurrent + +because we've already +shown that. + +So all the states are +positive-recurrent. + +Then you still have to show that +this inequality here is + +equality, and you've got to do +that by playing around with + +summing up these things. + +Something has been left +out, we have to sum + +those up over j. + +And that's another mess. + +I'm not going to do +it here in class. + +But just sort of see +why this happened. + +Yeah? + +AUDIENCE: [INAUDIBLE]. + +Why do you have to show +the equality? + +PROFESSOR: Why do I have +to the equality? + +Because if I want to show that +all of the pi sub i's are + +positive, how do I show that? + +All I've done is started +out with an arbitrary-- + +oh, I've started out with +an arbitrary j and + +an arbitrary t. + +Because I got the fact that this +was positive-recurrent by + +arguing that at least +one of the pi sub + +j's had to be positive. + +From this I can argue +that they're all + +positive-recurrent, which tells +me that this number is + +greater than 0. + +But that doesn't show me that +this number is greater than 0. + +But it is. + +I mean, it's all right. + +It all works out. + +But not quite in such a simple +way as you would hope. + +OK, so now let's go back to +what we called birth-death + +chains, but look at a slightly +more general version of them. + +These are things that you-- + +I mean, queuing theory is +built on these things. + +Everything in queuing theory. + +Or not everything, but all the +things that come from a + +Poisson kind of background. + +All of these somehow look at +the birth-death chains. + +And the way a birth-death +chain works is you have + +arbitrary self-loops. + +You have positive probabilities +going from each + +state to the next state up. + +You have positive probabilities +going from the + +higher state to the +lower state. + +All transitions are +limited from-- + +i can only go to i plus 1, +or i, for i minus 1. + +You can't make big jumps. + +You can only make jumps +of one step. + +And other than that, it's +completely general. + +OK, now we go through an +interesting argument. + +We look at an arbitrary +state i. + +And for this arbitrary state i, +like i equals 2, we look at + +the number of transitions +that go from 2 to 3. + +And the number transitions that +go from 3 to 2 for any + +old sample path whatsoever. + +And for any sample path, +the number of + +transitions that go up-- + +if we start down there, before +you can come back, + +you've got to go up. + +So if you're on that side, you +have one more up transition + +than you have down transition. + +If you're on that side, you +have the same number of up + +transitions and down +transitions. + +So that as you look over a +longer and longer time, the + +number of up transitions is +effectively the same as the + +number of down transitions. + +If you have a steady-state, pi +sub i is the fraction of time + +you're in state i. + +pi sub i times p sub i is the +fraction of time you're going + +from state i to state +i plus 1. + +And pi sub i by plus 1 times q +sub i plus 1 is the fraction + +of time you're going +from state i plus 1 + +down to state i. + +What we've just argued by the +fact that sample path averages + +and ensemble averages have to +be equal is that pi sub i + +times p sub i is equal to +pi sub i plus 1 times + +q sub i plus 1. + +In the next slide, I will +talk about whether to + +believe that or not. + +For the moment, let's +say we believe it. + +And from this equation, we +see that the steady-state + +probability of i plus 1 is +equal to the steady-state + +probability of i times p sub +i over q sub i plus 1. + +It says that the steady-state +probability of each pi is + +determined by the steady-state +probability of the state + +underneath it. + +So you just go up. + +You can calculate the +steady-state of each, the + +probability of each if you know +the probability of the + +state below it. + +So if you recurse on this, pi +sub i plus 1 is equal to pi + +sub i times this ratio is equal +to pi sub i minus 1 + +times this ratio times p sub i +minus 1 over q sub i is equal + +to pi sub i minus 2 times +this triple of things. + +It tells you that what you want +to do is define row sub i + +as the difference of these two +probabilities, namely rob i, + +for any state i, is the ratio +of that probability to that + +probability. + +And this equation then turns +into pi sub i plus 1 equals pi + +sub i times row sub i. + +If you put all those +things together-- + +if you just paste them one after +the other, the way I was + +suggesting-- + +what you get is pi sub i is +equal to pi sub 0 times this + +product of terms. + +The product of terms looks +a little ugly. + +Why don't I care about +that very much? + +Well, because usually, when you +have a chain like this, + +all the Ps are the same and +all the Qs are the same-- + +or all the Ps are the same for +some point beyond someplace, + +they're are different +before that. + +There's always some structure +to make life easy for you. + +Oh, that's my computer. + +It's telling me what +time it is. + +I'm sorry. + +OK. + +So pi sub i is this. + +We then have to calculate +pi sub 0. + +Pi sub 0 is then 1 divided +by the sum of all the + +probabilities is pi sub 0 times +all those other things. + +It's 1 plus the sum here. + +And now if you don't believe +what I did here, and I don't + +blame you for being a little +bit skeptical. + +If you don't believe this, then +you look at this and you + +say, OK, I can now go back and +look at the steady state + +equations themselves and I can +plug this into the steady + +state equations themselves. + +And you will immediately see +that this solution satisfies + +the steady state equations. + +OK. + +Oh, damn. + +Excuse my language. + +OK. + +So we have our birth-death +chain with all these + +transitions here. + +We have our solution to it. + +Note that the solution is only +a function of these rows. + +It's only a function of the +ratio of p sub i to + +Q sub i plus 1. + +It doesn't depend on those +self loops at all. + +Isn't that peculiar? + +Completely independent of what +those self loops are. + +Well, you'll see later that it's +not totally independent + +of it, but it's essentially +independent of it. + +And you think about that for a +while and suddenly it's not + +that confusing because those +equations have come from + +looking at up transitions +and down transitions. + +By looking at an up transition +and a down transition at one + +place here, it tells you +something about the fraction + +of time you're over there and +the fraction of time you're + +down there if you know what +these steady state + +probabilities are. + +So if you think about it for a +bit, you realize that these + +steady state probabilities +cannot depend that strongly on + +what those self loops are. + +So this all sort +of makes sense. + +The next thing is the expression +for pi 0-- + +namely this thing here-- + +is a product of these terms. + +It converges and therefore the +chain is positive recurrent + +because there is a solution to +the steady state equation. + +It converges if the +row sub i's are + +asymptotically less than 1. + +So for example, if +the row sub i's-- + +beyond i equals 100-- + +are bounded by, say, 0.9, then +these terms have to go to 0 + +rapidly after i equals 100 and +this product has to converge. + +I say essentially here of all +these particular cases where + +the row sub i's are very close +to 1, and they're converging + +very slowly to 1 +and who knows. + +But for most of the things we +do, these row sub i's are + +strictly less than +1 as you move up. + +And it says that you have +to have steady state + +probabilities. + +So for most birth-death chains, +it's almost immediate + +to establish whether it's +recurrent, positive recurrent, + +or not positive recurrent. + +And we'll talk more about that +when we get into Markov + +processes, but that's enough +of it for now. + +Comment on methodology. + +We could check the renewal +results carefully, because + +what we're doing here is +assuming something rather + +peculiar about time averages +and ensemble averages. + +And sometimes you have to worry +about those things, but + +here, we don't have to worry +about it because we have this + +major theorem which tells +us if steady state + +probabilities exist-- + +and they exist because they +satisfy these equations-- + +then you have positive +recurrence. + +So it says the methodology to +use is not to get involved in + +any deep theory, but just +to see if these + +equations are satisfied. + +Again, good mathematicians +are lazy-- + +good engineers are +even lazier. + +That's my motto of the day. + +And finally, birth-death +chains are going to be + +particularly useful in queuing +where the births are arrivals + +and the deaths are departures. + +OK. + +Now we come to reversibility. + +I'm glad we're coming to that +towards the end of the lecture + +because reversibility is +something which I don't think + +any of you guys even-- + +and I think this is a +pretty smart class-- + +but I've never seen anybody who +understands reversibility + +the first time they +think about it. + +It's a very peculiar concept and +the results coming from it + +are peculiar, and we will have +to live with it for a while. + +But let's start out with +the easy things-- + +just with a definition of +what a Markov chain is. + +This top equation here says +that the probability of a + +whole bunch of states-- + +X sub n plus k down to X sub n +plus 1 given the stated time, + +n, down to the stated time 0. + +Because of the Markov condition, +that has to be + +equal to the probability +of these terms + +just given X sub n. + +Namely, if you know what X sub +n is, for the future, you + +don't have to know what any of +those previous states are. + +You get that directly from +where we started with the + +Markov chains-- the probability +of X sub n plus 1, + +given all this stuff, and +then you just add the + +other things onto it. + +Now, if you define A plus as any +event which is defined in + +terms of X sub n plus 1, X of n +plus 2, and so forth up, and + +if you define A minus as +anything which is a function + +of X sub n minus 1, X sub n +minus 2, down to X sub 0, then + +what this equations +says is that the + +probability of any A plus-- + +given X sub n and A minus-- + +is equal to the probability +of A plus given X sub n. + +And this hasn't gotten +hard yet. + +If you think this is +hard, just wait. + +If we now multiply this by +the probability of A + +minus given X sub n-- + +and what I'm trying to get at +is, how do you reason about + +the probabilities of +earlier states + +given the present state? + +We're used to proceeding +in time. + +We're used to looking at +the past for telling + +what the future is. + +And every once and a while, you +want to look at the future + +and predict what the +past had to be. + +It's probably more important to +talk about the future given + +the past, because sometimes +you don't know + +what the future is. + +But mathematically, you +have to sort that out. + +So if we multiply this equation +by the probability of + +A minus, given X sub n, +we don't know what + +that is, but it exists. + +It's a defined conditional +probability. + +Then what we get is the +probability of A plus and A + +minus, given X sub n, is equal +to the probability of A plus, + +given X sub n, times the +probability of A + +minus, given X sub n. + +So that the probability of the +future and the past, given + +what's happening now, is equal +to the probability of the + +future, given what's happening +now, times the probability the + +past, given what's +happening now. + +Which may be a more interesting +way of looking at + +past and future and present +than this totally + +asymmetric way here. + +This is a nice, symmetric +way of looking at it. + +And as soon as you see that this +has to be true, then you + +can turn around and write this +the opposite way, and you see + +that the probability of A minus, +given X sub n, and A + +plus is equal to the +probability of A + +minus given X sub n. + +Which says that the probability +of the past, given + +X sub n and the future, is equal +to the probability of + +the past just given X sub n. + +You can go from past the future +or you can go from + +future to past. + +And incidentally, if you people +have trouble trying to + +think of the past and +the future as + +being symmetric animals-- + +and I do too-- + +everything we do with time can +also be done on a line going + +from left to right, or it +can be done on a line + +going from bottom up. + +Going from bottom up, it's +hard to say that this is + +symmetric to this. + +If you look at it on a line +going from left to right, it's + +kind of easy to see that this +is symmetric between left to + +right and right to left. + +So every time you get confused +about these arguments, put + +them on a line and argue right +to left and left to right + +instead of earlier and later. + +Because mathematically, it's +the same thing, but it's + +easier to see these +symmetries. + +And now, if you think of A minus +as being X sub n minus + +1, and you think of A plus as +being X sub n plus 1, X sub n + +plus 2 and so forth up, what +this equation says is that the + +probability of the last state +in the past, given the state + +now and everything in the +future, is equal to the + +probability of the last state +in the past given X sub n. + +Now, this isn't reversibility. + +I'm not saying that these +are special process. + +This is true for any Markov +chain in the world. + +These relationships +are always true. + +This is one reason why many +people view this as the real + +Markov condition, as opposed to +any of these other things. + +They say that three events +have a Markov condition + +between them if there's +one of them which is + +in between the other. + +Where you can say that the +probability of the left one, + +given the middle one, times +the right one, given the + +middle one, is equal to the +probability of the left and + +the right given the middle. + +It says that the past and the +future, given the present, are + +independent of each other. + +It says that as soon as you +know what the present is, + +everything down there +is independent of + +everything up there. + +That's a pretty powerful +condition. + +And you'll see that we can do an +awful lot with it, so it's + +going to be important. + +OK. + +So let's go on with that. + +By Bayes rule-- + +and incidentally, this is why +Bayes got into so much trouble + +with the other statisticians +in the world. + +Because the other statisticians +in the world + +really got emotionally upset at +the idea of talking about + +the past given the future. + +That was almost an attack on +their religion as well as all + +the mathematics they knew and +everything else they knew. + +It was really hitting them below +the belt, so to speak. + +So they didn't like this. + +But now, we've recognized that +Bayes' Law is just the + +consequence of the axioms of +probability, and there's + +nothing strange about it. + +You write down these conditional +probabilities and + +that's sitting there, +facing you. + +But what it says here is that +the probability of the state + +at time n minus 1, given the +state of time n, is equal to + +the probability of the state +of time n, given n minus 1, + +times the probability of X +n minus 1 divided by the + +probability of X n. + +In other words, you put this +over in this side, and it says + +the probability of X n times the +probability of X n minus 1 + +given X n is that probability +up there. + +It says that the probability +of A given B times the + +probability of B is equal to the +probability of A times the + +probability of B given A. And +that's just the definition of + +a conditional probability, +nothing more. + +OK. + +If the forward chain is in +a steady state, then the + +probability that X sub n minus +1 equals j, given X sub n + +equals i, is pji times pi sub +j divided by pi sub i. + +These probabilities become +just probabilities which + +depend on i but not on n. + +Now what's going on here is +when you look at this + +equation, it looks peculiar +because normally with a Markov + +chain, we start out at time 0 +with some assumed probability + +distribution. + +And as soon as you start out +with some assumed probability + +distribution at time 0 and you +start talking about the past + +condition on the future, +it gets very sticky. + +Because when you talk about +the past condition on the + +future, you can only go back to +time equals 0, and you know + +what's happening down there +because you have some + +established probabilities +at 0. + +So what it says is in this +equation here, it says that + +the Markov chain, defined +by this rule-- + +I guess I ought to back +and look at the + +previous slide for that. + +This is saying the probability +of the state at time n minus + +1, conditional on the entire +future, is equal to the + +probability of X sub n minus +1 just given X sub n. + +This is the Markov condition, +but it's the Markov condition + +turned around. + +Usually we talk about the next +state given the previous state + +and everything before that. + +Here, we're talking about +the previous state given + +everything after that. + +So this really is the Markov +condition on what we might + +view as a backward chain. + +But to be a Markov chain, these +transition probabilities + +have to be independent of n. + +The transition probabilities +are not going to be + +independent of n if you have +these arbitrary probabilities + +at time 0 lousing +everything up. + +So you can get around +this in two ways. + +One way to get around it is +to say let's restrict our + +attention to positive recurrent +processes which are + +starting out in a +steady state. + +And if we start out in a steady +state, then these + +probabilities here-- + +looking at these probabilities +here-- + +if you go from here down to +here, you'll find out that + +this does not depend on n. + +And if you have an initial state +which is something other + +than steady state, then these +will depend on it. + +Let me put this down in +the next chain up. + +The probability of X sub n minus +1 given X sub n is going + +to be independent of n if this +is independent of n, which it + +is, because we have a +homogeneous Markov chain. + +And this is independent of n and +this is independent of n. + +Now, this will just be the +probability of pi sub i if X + +sub n minus 1 is equal to i. + +And this will be pi sub i if +probability of X sub n is + +equal to i. + +So this and this will be +independent of n if in fact we + +start out in a steady state. + +In other words, it won't be. + +So what we're doing here is we +normally think of a Markov + +chain starting out at time 0 +because how else can you get + +it started? + +And we think of it in forward +time, and then we say, well, + +we want to make it homogeneous, +because we want + +to make it always do the same +thing in the future otherwise + +it doesn't really look much +like the a Markov chain. + +So what we're saying is that +this backward chain-- we have + +backward probabilities +defined now-- + +the backward probabilities are +homogeneous if the forward + +probabilities start +in a steady state. + +You could probably make a +similar statement but say the + +forward probabilities are +homogeneous if the backward + +probabilities start +in a steady state. + +But I don't know when you're +going to start. + +You're going to have to start it +sometime in the future, and + +that gets too philosophical +to understand. + +OK. + +If we think of the chain as +starting in a steady state at + +time minus infinity, these are +also the equations of the + +homogeneous Markov chain. + +We can start at time minus +infinity wherever we want to-- + +it doesn't make any +difference-- + +because by the time we get to +state 0, we will be in steady + +state, and the whole range of +where we want to look at + +things will be in +steady state. + +OK. + +So aside from this issue about +starting at 0 and steady state + +and things like that, what we've +really shown here is + +that you can look at a Markov +chain either going forward or + +going backward. + +Or look at it going rightward +or going leftward. + +And that's really pretty +important. + +OK. + +That still doesn't say anything +about it being + +reversible. + +What reversibility is-- + +it comes from looking at +this equation here. + +This says what the transition +probabilities are, going + +backwards, and this +is the transition + +probabilities going forward. + +These are the steady state +probabilities. + +And if we define P star of ji +as a backward transition + +probabilities-- + +namely, the probability that at +this time or in stage A-- + +given that in this next time, +which to us, is the previous + +time, we're in state i, is the +probability of going in a + +backward direction +from j to i. + +This gets into whether this is +P star of ij or P star of ij. + +But I did check it carefully, +so it has to be right. + +So anyway, when you substitute +this in for this, the + +conditions that you get is pi +sub i times P star of ij is + +equal to pi j times P of ji. + +These are the same equations +that we had for + +a birth-death chain. + +But now, we're not talking +about birth-death chains. + +Now we're talking about +any old chain. + +Yeah? + +AUDIENCE: Doesn't this only +make sense for positive + +recurring chains? + +PROFESSOR: Yes. + +Sorry. + +I should keep emphasizing that, +because it only makes + +sense when you can define the +steady state probabilities. + +Yes. + +The steady state probabilities +are necessary in order to even + +define this P star of ji. + +But once you have that steady +state condition, and once you + +know what the steady state +probabilities are, then you + +can calculate backward +probabilities, you can + +calculate forward probabilities, +and this is a + +very simple relationship +that they satisfy. + +It makes sense because this +is a normal form. + +You look at state transition +probabilities and you look at + +the probability of being in +one state and then the + +probability of going +to the next state. + +And the question is the +next state back there + +or is it over there? + +And if it's a star, then it +means it's back there. + +And then we define a chain as +being reversible if P star of + +ij is equal to P sub ij, +for all i and all j. + +And what that means is that +all birth-death chains are + +reversible. + +And now let me show you +what that means. + +If we look at arrivals and +departures for a birth-death + +change, sometimes you go in a +self loop, so you don't go up + +and you don't go down. + +Other times you either +go down or you go up. + +We have arrivals coming in. + +Arrivals correspond to upper +transitions, departures + +correspond to downward +transitions so that when you + +look at it in a normal way, +you start out at time 0. + +You're in state 0. + +You have an arrival. + +Nothing happens for a while. + +You have another arrival, but +this time, you have a + +departure, you have another +departure, and you wind up in + +state 0 again. + +As far states are concerned, +you go from + +state 0 to state 1. + +You stay in state 1. + +In other words, this is the +difference between arrivals + +and departures. + +This is what the state is. + +You stay in state 1. + +Then you go up and you get +another arrival, you get a + +departure, and then you +get a departure, + +according to this chain. + +Now, let's look at it +coming in this way. + +When we look at it +coming backwards + +in time, what happens? + +We're going along here, +we're in state 0, + +suddenly we move up. + +If we want to view this as a +backward moving Markov chain, + +this corresponds to an +arrival of something. + +This corresponds to +another arrival. + +This corresponds +to a departure. + +We go along here with nothing +else happening, we get another + +departure, and there we are back +in a steady state again. + +And for any birth-death +chain, we can do this. + +Because any birth-death chain +we can look at as an arrival + +and departure process. + +We have arrivals, we +have departures-- + +we might have states +that go negative. + +That would be rather awkward, +but we can have that. + +But now, if we know that these +steady state probabilities + +govern the probability of +arrivals and the probabilities + +of departures, if we know that +we have reversibility, then + +these events here have the +same probability as these + +events here. + +It means that when we look at +things going from right back + +to left, it means that the +things that we viewed as + +departures here look +like arrivals. + +And what we're going to do next +time is use that to prove + +Burke's Theorem, which says +using this idea that if you + +look at the process of +departures in a birth-death + +chain where arrivals are all +with probability P and + +departures are all with +probability Q, then you get + +this nice set of probabilities +for arrivals and departures. + +Arrivals are independent +of everything else-- + +same probability at every +unit of time. + +Departures are the same way. + +But when you're looking from +left to right, you can only + +get departures when your state +is greater than 0. + +When you're coming in looking +this way, these things that + +looked like departures before +are looking like arrivals. + +These arrivals form a Bernoulli +Process, and the + +Bernoulli Process says that +given the future, the + +probability of a departure, +at any instant of time, is + +independent of everything +in the future. + +Now, that is not intuitive. + +If you think it's intuitive, +go back and think again. + +Because it's not. + +But anyway, I'm going +to stop here. + +You have this to mull over. + +We will try to sort it out +a little more next time. + +This is something that's going +to take your cooperation to + +sort it out, also. \ No newline at end of file diff --git a/tEpU7QiRiUk.txt b/tEpU7QiRiUk.txt new file mode 100644 index 0000000000000000000000000000000000000000..f15e16a7fd538f14261f84e8b54a2c298b4c9fc6 --- /dev/null +++ b/tEpU7QiRiUk.txt @@ -0,0 +1,20147 @@ +align:start position:0% + +Okay. So, this this little bit that I + + align:start position:0% +Okay. So, this this little bit that I + + + align:start position:0% +Okay. So, this this little bit that I +sent out to you that of course was + + align:start position:0% +sent out to you that of course was + + + align:start position:0% +sent out to you that of course was +unreadable, but this way you know at + + align:start position:0% +unreadable, but this way you know at + + + align:start position:0% +unreadable, but this way you know at +least that I was trying + + align:start position:0% +least that I was trying + + + align:start position:0% +least that I was trying +um I I I wanted you to + + align:start position:0% +um I I I wanted you to + + + align:start position:0% +um I I I wanted you to +have a brief sense of of + + align:start position:0% + + + + align:start position:0% + +Tolken academic style which um you you + + align:start position:0% +Tolken academic style which um you you + + + align:start position:0% +Tolken academic style which um you you +will or would or have discovered um is + + align:start position:0% +will or would or have discovered um is + + + align:start position:0% +will or would or have discovered um is +not all that dissimilar from from his + + align:start position:0% +not all that dissimilar from from his + + + align:start position:0% +not all that dissimilar from from his +literary style. Actually, let's let's + + align:start position:0% +literary style. Actually, let's let's + + + align:start position:0% +literary style. Actually, let's let's +back up a moment. Um, how how much of + + align:start position:0% +back up a moment. Um, how how much of + + + align:start position:0% +back up a moment. Um, how how much of +this uh fantasy literature have you all + + align:start position:0% +this uh fantasy literature have you all + + + align:start position:0% +this uh fantasy literature have you all +read? Lewis, have you read all all seven + + align:start position:0% +read? Lewis, have you read all all seven + + + align:start position:0% +read? Lewis, have you read all all seven +Narnia books? Do you do you agree? + + align:start position:0% +Narnia books? Do you do you agree? + + + align:start position:0% +Narnia books? Do you do you agree? +Nothing. Okay. I don't remember most of + + align:start position:0% +Nothing. Okay. I don't remember most of + + + align:start position:0% +Nothing. Okay. I don't remember most of +it because I read it when I was like + + align:start position:0% +it because I read it when I was like + + + align:start position:0% +it because I read it when I was like +seven. Yeah. Yeah. + + align:start position:0% +seven. Yeah. Yeah. + + + align:start position:0% +seven. Yeah. Yeah. +I just recently read in the wardrobe. + + align:start position:0% +I just recently read in the wardrobe. + + + align:start position:0% +I just recently read in the wardrobe. +Uhhuh. I read the that and the the great + + align:start position:0% +Uhhuh. I read the that and the the great + + + align:start position:0% +Uhhuh. I read the that and the the great +divorce. And the great divorce. Any any + + align:start position:0% +divorce. And the great divorce. Any any + + + align:start position:0% +divorce. And the great divorce. Any any +of you read the screw tape letters? I + + align:start position:0% +of you read the screw tape letters? I + + + align:start position:0% +of you read the screw tape letters? I +keep meaning to. I have it. + + align:start position:0% +keep meaning to. I have it. + + + align:start position:0% +keep meaning to. I have it. +Yeah. Okay. Okay. Well, what what did + + align:start position:0% +Yeah. Okay. Okay. Well, what what did + + + align:start position:0% +Yeah. Okay. Okay. Well, what what did +you think about Caner's + + align:start position:0% +you think about Caner's + + + align:start position:0% +you think about Caner's +uh assessment of the Narnia series as + + align:start position:0% +uh assessment of the Narnia series as + + + align:start position:0% +uh assessment of the Narnia series as +uneven and very much for children, for + + align:start position:0% +uneven and very much for children, for + + + align:start position:0% +uneven and very much for children, for +school boys, right? Not just children. I + + align:start position:0% +school boys, right? Not just children. I + + + align:start position:0% +school boys, right? Not just children. I +was confused more about like I had been + + align:start position:0% +was confused more about like I had been + + + align:start position:0% +was confused more about like I had been +told and I learned of C. Louis more as a + + align:start position:0% +told and I learned of C. Louis more as a + + + align:start position:0% +told and I learned of C. Louis more as a +born again Christian, not as what they + + align:start position:0% +born again Christian, not as what they + + + align:start position:0% +born again Christian, not as what they +were talking about, which was, you know, + + align:start position:0% +were talking about, which was, you know, + + + align:start position:0% +were talking about, which was, you know, +the pessimistic and stuff like that and + + align:start position:0% +the pessimistic and stuff like that and + + + align:start position:0% +the pessimistic and stuff like that and +depressive religious stuff. And in fact, + + align:start position:0% +depressive religious stuff. And in fact, + + + align:start position:0% +depressive religious stuff. And in fact, +what I found always with the Narnia ones + + align:start position:0% +what I found always with the Narnia ones + + + align:start position:0% +what I found always with the Narnia ones +and especially with the great divorce + + align:start position:0% +and especially with the great divorce + + + align:start position:0% +and especially with the great divorce +was it was really really uplifting + + align:start position:0% +was it was really really uplifting + + + align:start position:0% +was it was really really uplifting +because unlike a lot of other Christian + + align:start position:0% +because unlike a lot of other Christian + + + align:start position:0% +because unlike a lot of other Christian +things where it was sort of pressing + + align:start position:0% +things where it was sort of pressing + + + align:start position:0% +things where it was sort of pressing +down on you that there was this good, + + align:start position:0% +down on you that there was this good, + + + align:start position:0% +down on you that there was this good, +you know, horrible evil and wonderful + + align:start position:0% +you know, horrible evil and wonderful + + + align:start position:0% +you know, horrible evil and wonderful +good, but it was the human choice of + + align:start position:0% +good, but it was the human choice of + + + align:start position:0% +good, but it was the human choice of +which one they wanted and they could + + align:start position:0% +which one they wanted and they could + + + align:start position:0% +which one they wanted and they could +choose and they could change their mind + + align:start position:0% +choose and they could change their mind + + + align:start position:0% +choose and they could change their mind +a few times and stuff like that. And + + align:start position:0% +a few times and stuff like that. And + + + align:start position:0% +a few times and stuff like that. And +that was what was so uplifting to it, + + align:start position:0% +that was what was so uplifting to it, + + + align:start position:0% +that was what was so uplifting to it, +which really confused me then. Like + + align:start position:0% +which really confused me then. Like + + + align:start position:0% +which really confused me then. Like +Caner, I mean, we're going to talk about + + align:start position:0% +Caner, I mean, we're going to talk about + + + align:start position:0% +Caner, I mean, we're going to talk about +this, but but Caner doesn't really like + + align:start position:0% +this, but but Caner doesn't really like + + + align:start position:0% +this, but but Caner doesn't really like +either of these characters, does he? + + align:start position:0% +either of these characters, does he? + + + align:start position:0% +either of these characters, does he? +Want to ring his neck? You wanted to + + align:start position:0% +Want to ring his neck? You wanted to + + + align:start position:0% +Want to ring his neck? You wanted to +ring Caner's neck? Oh, okay. Okay. All + + align:start position:0% +ring Caner's neck? Oh, okay. Okay. All + + + align:start position:0% +ring Caner's neck? Oh, okay. Okay. All +right. Well, you'll get your chance to + + align:start position:0% +right. Well, you'll get your chance to + + + align:start position:0% +right. Well, you'll get your chance to +ring Caner's neck. Um, so, okay. So, + + align:start position:0% +ring Caner's neck. Um, so, okay. So, + + + align:start position:0% +ring Caner's neck. Um, so, okay. So, +let's let's hold on to that. So, Lewis + + align:start position:0% +let's let's hold on to that. So, Lewis + + + align:start position:0% +let's let's hold on to that. So, Lewis +is fairly wellknown in at least the + + align:start position:0% +is fairly wellknown in at least the + + + align:start position:0% +is fairly wellknown in at least the +vaguest and general sense, except for + + align:start position:0% +vaguest and general sense, except for + + + align:start position:0% +vaguest and general sense, except for +Anarie, who didn't grow up in the United + + align:start position:0% +Anarie, who didn't grow up in the United + + + align:start position:0% +Anarie, who didn't grow up in the United +States, right? So I mean part part of + + align:start position:0% +States, right? So I mean part part of + + + align:start position:0% +States, right? So I mean part part of +the point that Caner is making here that + + align:start position:0% +the point that Caner is making here that + + + align:start position:0% +the point that Caner is making here that +I think is valid is that um that there's + + align:start position:0% +I think is valid is that um that there's + + + align:start position:0% +I think is valid is that um that there's +this particular kind of intellectual + + align:start position:0% +this particular kind of intellectual + + + align:start position:0% +this particular kind of intellectual +uh space which opens up in Britain + + align:start position:0% +uh space which opens up in Britain + + + align:start position:0% +uh space which opens up in Britain +between the wars and and into World War + + align:start position:0% +between the wars and and into World War + + + align:start position:0% +between the wars and and into World War +II that appeals for maybe some set of + + align:start position:0% +II that appeals for maybe some set of + + + align:start position:0% +II that appeals for maybe some set of +bizarre reasons. You want to sit + + align:start position:0% +bizarre reasons. You want to sit + + + align:start position:0% +bizarre reasons. You want to sit +probably down at that end um to + + align:start position:0% +probably down at that end um to + + + align:start position:0% +probably down at that end um to +Americans in particular. And so we can + + align:start position:0% +Americans in particular. And so we can + + + align:start position:0% +Americans in particular. And so we can +think about we can think about that too, + + align:start position:0% +think about we can think about that too, + + + align:start position:0% +think about we can think about that too, +right? What's going on with that? Okay, + + align:start position:0% +right? What's going on with that? Okay, + + + align:start position:0% +right? What's going on with that? Okay, +so what about + + align:start position:0% +so what about + + + align:start position:0% +so what about +Tolken? Uh, so okay, we've all we've all + + align:start position:0% +Tolken? Uh, so okay, we've all we've all + + + align:start position:0% +Tolken? Uh, so okay, we've all we've all +seen the movie recently. We we No. Yeah, + + align:start position:0% +seen the movie recently. We we No. Yeah, + + + align:start position:0% +seen the movie recently. We we No. Yeah, +I'm the odd one out. Never read the + + align:start position:0% +I'm the odd one out. Never read the + + + align:start position:0% +I'm the odd one out. Never read the +books, never seen the movies. Oh, + + align:start position:0% +books, never seen the movies. Oh, + + + align:start position:0% +books, never seen the movies. Oh, +really? I know nothing about + + align:start position:0% +really? I know nothing about + + + align:start position:0% +really? I know nothing about +Huh. Okay. Is that Is that right? Odd + + align:start position:0% +Huh. Okay. Is that Is that right? Odd + + + align:start position:0% +Huh. Okay. Is that Is that right? Odd +odd one out. The rest of you I'm pretty + + align:start position:0% +odd one out. The rest of you I'm pretty + + + align:start position:0% +odd one out. The rest of you I'm pretty +sure I'm the odd one out since I'm + + align:start position:0% +sure I'm the odd one out since I'm + + + align:start position:0% +sure I'm the odd one out since I'm +always the odd one out when I say that. + + align:start position:0% +always the odd one out when I say that. + + + align:start position:0% +always the odd one out when I say that. +So No, I know one other person. + + align:start position:0% +So No, I know one other person. + + + align:start position:0% +So No, I know one other person. +But you've all read the books in + + align:start position:0% +But you've all read the books in + + + align:start position:0% +But you've all read the books in +addition to + + align:start position:0% +addition to + + + align:start position:0% +addition to +Oh, everything. + + align:start position:0% +Oh, everything. + + + align:start position:0% +Oh, everything. +Okay. Okay. Right. The whole the whole + + align:start position:0% +Okay. Okay. Right. The whole the whole + + + align:start position:0% +Okay. Okay. Right. The whole the whole +nine yards and then some. + + align:start position:0% +nine yards and then some. + + + align:start position:0% +nine yards and then some. +Okay. Well, okay. Good. Good. So, so we + + align:start position:0% +Okay. Well, okay. Good. Good. So, so we + + + align:start position:0% +Okay. Well, okay. Good. Good. So, so we +we have a my assumption coming in was + + align:start position:0% +we have a my assumption coming in was + + + align:start position:0% +we have a my assumption coming in was +that we would be fairly mutually + + align:start position:0% +that we would be fairly mutually + + + align:start position:0% +that we would be fairly mutually +literate + + align:start position:0% +literate + + + align:start position:0% +literate +um in this respect. + + align:start position:0% +um in this respect. + + + align:start position:0% +um in this respect. +Let me start by taking us back to last + + align:start position:0% +Let me start by taking us back to last + + + align:start position:0% +Let me start by taking us back to last +week. As I was saying, when I was first + + align:start position:0% +week. As I was saying, when I was first + + + align:start position:0% +week. As I was saying, when I was first +handing back the discussion papers, it + + align:start position:0% +handing back the discussion papers, it + + + align:start position:0% +handing back the discussion papers, it +was clear not only from our + + align:start position:0% +was clear not only from our + + + align:start position:0% +was clear not only from our +conversation, but then going back and + + align:start position:0% +conversation, but then going back and + + + align:start position:0% +conversation, but then going back and +reading your discussion notes um after + + align:start position:0% +reading your discussion notes um after + + + align:start position:0% +reading your discussion notes um after +class that that um Binham's book was + + align:start position:0% +class that that um Binham's book was + + + align:start position:0% +class that that um Binham's book was +deeply disturbing. + + align:start position:0% + + + + align:start position:0% + +Yes. Okay. And uh I I wish I wish Greg + + align:start position:0% +Yes. Okay. And uh I I wish I wish Greg + + + align:start position:0% +Yes. Okay. And uh I I wish I wish Greg +were here because in particular Greg had + + align:start position:0% +were here because in particular Greg had + + + align:start position:0% +were here because in particular Greg had +he said this in class but then he also + + align:start position:0% +he said this in class but then he also + + + align:start position:0% +he said this in class but then he also +again emphasized it in his in his + + align:start position:0% +again emphasized it in his in his + + + align:start position:0% +again emphasized it in his in his +discussion paper uh that that the book + + align:start position:0% +discussion paper uh that that the book + + + align:start position:0% +discussion paper uh that that the book +was so different. her argument, the + + align:start position:0% +was so different. her argument, the + + + align:start position:0% +was so different. her argument, the +things she was talking about were so + + align:start position:0% +things she was talking about were so + + + align:start position:0% +things she was talking about were so +different than than the + + align:start position:0% +different than than the + + + align:start position:0% +different than than the +Catholic institution that he understood + + align:start position:0% +Catholic institution that he understood + + + align:start position:0% +Catholic institution that he understood +from, you know, his childhood experience + + align:start position:0% +from, you know, his childhood experience + + + align:start position:0% +from, you know, his childhood experience +and and and whatever else. Um, and one + + align:start position:0% +and and and whatever else. Um, and one + + + align:start position:0% +and and and whatever else. Um, and one +of the things that we had talked about + + align:start position:0% +of the things that we had talked about + + + align:start position:0% +of the things that we had talked about +last week was at least the possibility + + align:start position:0% +last week was at least the possibility + + + align:start position:0% +last week was at least the possibility +that the piece of the medieval mental + + align:start position:0% +that the piece of the medieval mental + + + align:start position:0% +that the piece of the medieval mental +world that mine that Binham is exploring + + align:start position:0% +world that mine that Binham is exploring + + + align:start position:0% +world that mine that Binham is exploring +is one that has not particularly come + + align:start position:0% +is one that has not particularly come + + + align:start position:0% +is one that has not particularly come +forward to us. Although, right, we + + align:start position:0% +forward to us. Although, right, we + + + align:start position:0% +forward to us. Although, right, we +talked a little bit about um, uh, the + + align:start position:0% +talked a little bit about um, uh, the + + + align:start position:0% +talked a little bit about um, uh, the +fascination with this current um, + + align:start position:0% +fascination with this current um, + + + align:start position:0% +fascination with this current um, +Passion movie, right? and that that + + align:start position:0% +Passion movie, right? and that that + + + align:start position:0% +Passion movie, right? and that that +shares some of that um that particular + + align:start position:0% +shares some of that um that particular + + + align:start position:0% +shares some of that um that particular +kind of a medieval + + align:start position:0% +kind of a medieval + + + align:start position:0% +kind of a medieval +sensibility. + + align:start position:0% +sensibility. + + + align:start position:0% +sensibility. +Obviously Tolken and and maybe Lewis to + + align:start position:0% +Obviously Tolken and and maybe Lewis to + + + align:start position:0% +Obviously Tolken and and maybe Lewis to +a less obvious extent, but but Tolken in + + align:start position:0% +a less obvious extent, but but Tolken in + + + align:start position:0% +a less obvious extent, but but Tolken in +particular has very much reached into + + align:start position:0% +particular has very much reached into + + + align:start position:0% +particular has very much reached into +the present, right, with a with at least + + align:start position:0% +the present, right, with a with at least + + + align:start position:0% +the present, right, with a with at least +a medievalism, right? a kind of + + align:start position:0% +a medievalism, right? a kind of + + + align:start position:0% +a medievalism, right? a kind of +sensibility that is derived and we can + + align:start position:0% +sensibility that is derived and we can + + + align:start position:0% +sensibility that is derived and we can +talk about how medieval is it really uh + + align:start position:0% +talk about how medieval is it really uh + + + align:start position:0% +talk about how medieval is it really uh +but a sensibility that people understand + + align:start position:0% +but a sensibility that people understand + + + align:start position:0% +but a sensibility that people understand +to be medieval and and and which is + + align:start position:0% +to be medieval and and and which is + + + align:start position:0% +to be medieval and and and which is +totally + + align:start position:0% +totally + + + align:start position:0% +totally +appealing right mill billions and + + align:start position:0% +appealing right mill billions and + + + align:start position:0% +appealing right mill billions and +billions of dollars worth appealing. + + align:start position:0% +billions of dollars worth appealing. + + + align:start position:0% +billions of dollars worth appealing. +Um I mean aside from the fact that Caner + + align:start position:0% +Um I mean aside from the fact that Caner + + + align:start position:0% +Um I mean aside from the fact that Caner +doesn't like it very much although + + align:start position:0% +doesn't like it very much although + + + align:start position:0% +doesn't like it very much although +doesn't one suspect that he's just + + align:start position:0% +doesn't one suspect that he's just + + + align:start position:0% +doesn't one suspect that he's just +jealous. Yeah. Yeah. I mean there's that + + align:start position:0% +jealous. Yeah. Yeah. I mean there's that + + + align:start position:0% +jealous. Yeah. Yeah. I mean there's that +tone. I mean, he even talks about he he + + align:start position:0% +tone. I mean, he even talks about he he + + + align:start position:0% +tone. I mean, he even talks about he he +talks about the other Oxford Dons who + + align:start position:0% +talks about the other Oxford Dons who + + + align:start position:0% +talks about the other Oxford Dons who +were jealous and you could just tell he + + align:start position:0% +were jealous and you could just tell he + + + align:start position:0% +were jealous and you could just tell he +completely + + align:start position:0% +completely + + + align:start position:0% +completely +empathizes. Um, okay. So, we can we can + + align:start position:0% +empathizes. Um, okay. So, we can we can + + + align:start position:0% +empathizes. Um, okay. So, we can we can +we can write we can write down because + + align:start position:0% +we can write we can write down because + + + align:start position:0% +we can write we can write down because +he made money off of it, things like + + align:start position:0% +he made money off of it, things like + + + align:start position:0% +he made money off of it, things like +that. Anything that's popular and makes + + align:start position:0% +that. Anything that's popular and makes + + + align:start position:0% +that. Anything that's popular and makes +money is obviously not, you know, good + + align:start position:0% +money is obviously not, you know, good + + + align:start position:0% +money is obviously not, you know, good +enough quality for or something. Yeah, I + + align:start position:0% +enough quality for or something. Yeah, I + + + align:start position:0% +enough quality for or something. Yeah, I +think there's a piece of that. I mean + + align:start position:0% +think there's a piece of that. I mean + + + align:start position:0% +think there's a piece of that. I mean +there was a whole uh a + + align:start position:0% +there was a whole uh a + + + align:start position:0% +there was a whole uh a +Marxist school of thought in the really + + align:start position:0% +Marxist school of thought in the really + + + align:start position:0% +Marxist school of thought in the really +in the 70s I guess um coming out of the + + align:start position:0% +in the 70s I guess um coming out of the + + + align:start position:0% +in the 70s I guess um coming out of the +British public school system which is + + align:start position:0% +British public school system which is + + + align:start position:0% +British public school system which is +their private school system. So not to + + align:start position:0% +their private school system. So not to + + + align:start position:0% +their private school system. So not to +confuse you, uh that that was very anti- + + align:start position:0% +confuse you, uh that that was very anti- + + + align:start position:0% +confuse you, uh that that was very anti- +Tolken and and more or less the gist of + + align:start position:0% +Tolken and and more or less the gist of + + + align:start position:0% +Tolken and and more or less the gist of +it was this is so popular it's made so + + align:start position:0% +it was this is so popular it's made so + + + align:start position:0% +it was this is so popular it's made so +much money it it must be capitalism at + + align:start position:0% +much money it it must be capitalism at + + + align:start position:0% +much money it it must be capitalism at +its sort of rawest nakedest you know + + align:start position:0% +its sort of rawest nakedest you know + + + align:start position:0% +its sort of rawest nakedest you know +most vile manifestation which seems kind + + align:start position:0% +most vile manifestation which seems kind + + + align:start position:0% +most vile manifestation which seems kind +of ironic because I mean if there was + + align:start position:0% +of ironic because I mean if there was + + + align:start position:0% +of ironic because I mean if there was +ever a lite right it's our friend Tolken + + align:start position:0% +ever a lite right it's our friend Tolken + + + align:start position:0% +ever a lite right it's our friend Tolken +I mean he's not exactly you know um the + + align:start position:0% +I mean he's not exactly you know um the + + + align:start position:0% +I mean he's not exactly you know um the +entrepreneur u right on you know sort of + + align:start position:0% +entrepreneur u right on you know sort of + + + align:start position:0% +entrepreneur u right on you know sort of +right on the edge of his next million. + + align:start position:0% +right on the edge of his next million. + + + align:start position:0% +right on the edge of his next million. +Um but but anyway, uh that that + + align:start position:0% +Um but but anyway, uh that that + + + align:start position:0% +Um but but anyway, uh that that +accusation has been made, right? If if + + align:start position:0% +accusation has been made, right? If if + + + align:start position:0% +accusation has been made, right? If if +the masses appreciate it and pay for it, + + align:start position:0% +the masses appreciate it and pay for it, + + + align:start position:0% +the masses appreciate it and pay for it, +surely it can't be any + + align:start position:0% + + + + align:start position:0% + +good. So, and we so and we'll we'll + + align:start position:0% +good. So, and we so and we'll we'll + + + align:start position:0% +good. So, and we so and we'll we'll +we'll come back to that. But before we + + align:start position:0% +we'll come back to that. But before we + + + align:start position:0% +we'll come back to that. But before we +do that, how do we square + + align:start position:0% +do that, how do we square + + + align:start position:0% +do that, how do we square +binum with + + align:start position:0% +binum with + + + align:start position:0% +binum with +this medieval sensibility that you've + + align:start position:0% +this medieval sensibility that you've + + + align:start position:0% +this medieval sensibility that you've +now uh been exposed to in sort of its + + align:start position:0% +now uh been exposed to in sort of its + + + align:start position:0% +now uh been exposed to in sort of its +scholarly version in Lewis's The + + align:start position:0% +scholarly version in Lewis's The + + + align:start position:0% +scholarly version in Lewis's The +Discarded Image? I mean, this model that + + align:start position:0% +Discarded Image? I mean, this model that + + + align:start position:0% +Discarded Image? I mean, this model that +Lewis says is out there that everybody + + align:start position:0% +Lewis says is out there that everybody + + + align:start position:0% +Lewis says is out there that everybody +more or less subscribes to. This is the + + align:start position:0% +more or less subscribes to. This is the + + + align:start position:0% +more or less subscribes to. This is the +world and how they understand it. How + + align:start position:0% +world and how they understand it. How + + + align:start position:0% +world and how they understand it. How +does that square or even or even + + align:start position:0% +does that square or even or even + + + align:start position:0% +does that square or even or even +Tolken's madeup world that is at least + + align:start position:0% +Tolken's madeup world that is at least + + + align:start position:0% +Tolken's madeup world that is at least +um uh based right on his understanding + + align:start position:0% +um uh based right on his understanding + + + align:start position:0% +um uh based right on his understanding +of of a real medieval world? How do we + + align:start position:0% +of of a real medieval world? How do we + + + align:start position:0% +of of a real medieval world? How do we +square that with binum? Yeah, go ahead. + + align:start position:0% +square that with binum? Yeah, go ahead. + + + align:start position:0% +square that with binum? Yeah, go ahead. +Go ahead. Lewis made the assertion that + + align:start position:0% +Go ahead. Lewis made the assertion that + + + align:start position:0% +Go ahead. Lewis made the assertion that +the people in medieval society kept this + + align:start position:0% +the people in medieval society kept this + + + align:start position:0% +the people in medieval society kept this +stuff, this model and their religion + + align:start position:0% +stuff, this model and their religion + + + align:start position:0% +stuff, this model and their religion +entirely separate. I that that they that + + align:start position:0% +entirely separate. I that that they that + + + align:start position:0% +entirely separate. I that that they that +they tried to, you know, that that they + + align:start position:0% +they tried to, you know, that that they + + + align:start position:0% +they tried to, you know, that that they +could could could they could reconcile + + align:start position:0% +could could could they could reconcile + + + align:start position:0% +could could could they could reconcile +they didn't even reconcile these things + + align:start position:0% +they didn't even reconcile these things + + + align:start position:0% +they didn't even reconcile these things +in their head that they just they + + align:start position:0% +in their head that they just they + + + align:start position:0% +in their head that they just they +weren't like the two were just complet + + align:start position:0% +weren't like the two were just complet + + + align:start position:0% +weren't like the two were just complet +wholly separate and they could have + + align:start position:0% +wholly separate and they could have + + + align:start position:0% +wholly separate and they could have +these these in many cases uh what we + + align:start position:0% +these these in many cases uh what we + + + align:start position:0% +these these in many cases uh what we +might call contradictory views now and + + align:start position:0% +might call contradictory views now and + + + align:start position:0% +might call contradictory views now and +just didn't you know that was the way it + + align:start position:0% +just didn't you know that was the way it + + + align:start position:0% +just didn't you know that was the way it +is by their Okay. Yeah. Go ahead. + + align:start position:0% +is by their Okay. Yeah. Go ahead. + + + align:start position:0% +is by their Okay. Yeah. Go ahead. +I think talking from the present + + align:start position:0% +I think talking from the present + + + align:start position:0% +I think talking from the present +perspective like Louiswis's model is + + align:start position:0% +perspective like Louiswis's model is + + + align:start position:0% +perspective like Louiswis's model is +very familiar. Like I don't know if it's + + align:start position:0% +very familiar. Like I don't know if it's + + + align:start position:0% +very familiar. Like I don't know if it's +just more wellknown nothing that in this + + align:start position:0% +just more wellknown nothing that in this + + + align:start position:0% +just more wellknown nothing that in this +book that I read was really new to me. I + + align:start position:0% +book that I read was really new to me. I + + + align:start position:0% +book that I read was really new to me. I +don't think I don't know if that's + + align:start position:0% +don't think I don't know if that's + + + align:start position:0% +don't think I don't know if that's +because I've been exposed to medieval + + align:start position:0% +because I've been exposed to medieval + + + align:start position:0% +because I've been exposed to medieval +literature before but it was it was + + align:start position:0% +literature before but it was it was + + + align:start position:0% +literature before but it was it was +fairly standard and ordinary whereas as + + align:start position:0% +fairly standard and ordinary whereas as + + + align:start position:0% +fairly standard and ordinary whereas as +Greg said the bin was just + + align:start position:0% +Greg said the bin was just + + + align:start position:0% +Greg said the bin was just +extraordinary. So is that true for all + + align:start position:0% +extraordinary. So is that true for all + + + align:start position:0% +extraordinary. So is that true for all +of you? Is this a model that is readily + + align:start position:0% +of you? Is this a model that is readily + + + align:start position:0% +of you? Is this a model that is readily +accessible to you floating around in + + align:start position:0% +accessible to you floating around in + + + align:start position:0% +accessible to you floating around in +your head? + + align:start position:0% +your head? + + + align:start position:0% +your head? +Someone says, "Oh, that man is so + + align:start position:0% +Someone says, "Oh, that man is so + + + align:start position:0% +Someone says, "Oh, that man is so +color." And you know instantly or they + + align:start position:0% +color." And you know instantly or they + + + align:start position:0% +color." And you know instantly or they +say by Jove and you know instantly what + + align:start position:0% +say by Jove and you know instantly what + + + align:start position:0% +say by Jove and you know instantly what +is being invoked or you know if I was to + + align:start position:0% +is being invoked or you know if I was to + + + align:start position:0% +is being invoked or you know if I was to +break up a fight in the hallway and say + + align:start position:0% +break up a fight in the hallway and say + + + align:start position:0% +break up a fight in the hallway and say +ah the influence of Mars at work again + + align:start position:0% +ah the influence of Mars at work again + + + align:start position:0% +ah the influence of Mars at work again +everybody around me would know me. Is + + align:start position:0% +everybody around me would know me. Is + + + align:start position:0% +everybody around me would know me. Is +that true? + + align:start position:0% +that true? + + + align:start position:0% +that true? +Depends what you got of those yet. Two + + align:start position:0% +Depends what you got of those yet. Two + + + align:start position:0% +Depends what you got of those yet. Two +are three. Okay. So besides the + + align:start position:0% +are three. Okay. So besides the + + + align:start position:0% +are three. Okay. So besides the +references to um I guess gods which I + + align:start position:0% +references to um I guess gods which I + + + align:start position:0% +references to um I guess gods which I +just kind of have acquired over the + + align:start position:0% +just kind of have acquired over the + + + align:start position:0% +just kind of have acquired over the +years the influence of Mars and the + + align:start position:0% +years the influence of Mars and the + + + align:start position:0% +years the influence of Mars and the +relation to the planets everything else + + align:start position:0% +relation to the planets everything else + + + align:start position:0% +relation to the planets everything else +he mentioned was new to me and that + + align:start position:0% +he mentioned was new to me and that + + + align:start position:0% +he mentioned was new to me and that +might be because I had never I mean + + align:start position:0% +might be because I had never I mean + + + align:start position:0% +might be because I had never I mean +besides the Canterbury Tales which isn't + + align:start position:0% +besides the Canterbury Tales which isn't + + + align:start position:0% +besides the Canterbury Tales which isn't +even really that medieval the only + + align:start position:0% +even really that medieval the only + + + align:start position:0% +even really that medieval the only +exposure I have to that literature. So + + align:start position:0% +exposure I have to that literature. So + + + align:start position:0% +exposure I have to that literature. So +if you're not exposed to it I don't + + align:start position:0% +if you're not exposed to it I don't + + + align:start position:0% +if you're not exposed to it I don't +think you really have a place to pick it + + align:start position:0% +think you really have a place to pick it + + + align:start position:0% +think you really have a place to pick it +up until this book was very I learned a + + align:start position:0% +up until this book was very I learned a + + + align:start position:0% +up until this book was very I learned a +lot from it because I had never been + + align:start position:0% +lot from it because I had never been + + + align:start position:0% +lot from it because I had never been +exposed to it before. Good useful + + align:start position:0% +exposed to it before. Good useful + + + align:start position:0% +exposed to it before. Good useful +cocktail party information. + + align:start position:0% +cocktail party information. + + + align:start position:0% +cocktail party information. +Um, perhaps something to me. Go ahead, + + align:start position:0% +Um, perhaps something to me. Go ahead, + + + align:start position:0% +Um, perhaps something to me. Go ahead, +Nick. Yeah, that's I mean that's what I + + align:start position:0% +Nick. Yeah, that's I mean that's what I + + + align:start position:0% +Nick. Yeah, that's I mean that's what I +wrote about is that I had a real hard + + align:start position:0% +wrote about is that I had a real hard + + + align:start position:0% +wrote about is that I had a real hard +time connecting with the first part + + align:start position:0% +time connecting with the first part + + + align:start position:0% +time connecting with the first part +because I've never read like, you know, + + align:start position:0% +because I've never read like, you know, + + + align:start position:0% +because I've never read like, you know, +Chower or Dante or any any of those guys + + align:start position:0% +Chower or Dante or any any of those guys + + + align:start position:0% +Chower or Dante or any any of those guys +and like he kept like quoting them and + + align:start position:0% +and like he kept like quoting them and + + + align:start position:0% +and like he kept like quoting them and +stuff and it was like yeah, I had the + + align:start position:0% +stuff and it was like yeah, I had the + + + align:start position:0% +stuff and it was like yeah, I had the +same issue that he kept putting in all + + align:start position:0% +same issue that he kept putting in all + + + align:start position:0% +same issue that he kept putting in all +this evidence and I couldn't put it into + + align:start position:0% +this evidence and I couldn't put it into + + + align:start position:0% +this evidence and I couldn't put it into +context of where this evidence came + + align:start position:0% +context of where this evidence came + + + align:start position:0% +context of where this evidence came +from. It was like I was like, "Yeah, + + align:start position:0% +from. It was like I was like, "Yeah, + + + align:start position:0% +from. It was like I was like, "Yeah, +that makes sense, but it would be a lot + + align:start position:0% +that makes sense, but it would be a lot + + + align:start position:0% +that makes sense, but it would be a lot +more rewarding if I knew exactly the + + align:start position:0% +more rewarding if I knew exactly the + + + align:start position:0% +more rewarding if I knew exactly the +context that that evidence came in." + + align:start position:0% +context that that evidence came in." + + + align:start position:0% +context that that evidence came in." +What were you going to say, Miranda? I + + align:start position:0% +What were you going to say, Miranda? I + + + align:start position:0% +What were you going to say, Miranda? I +guess I had a lot of it was more like I + + align:start position:0% +guess I had a lot of it was more like I + + + align:start position:0% +guess I had a lot of it was more like I +had sort of known some of these ideas + + align:start position:0% +had sort of known some of these ideas + + + align:start position:0% +had sort of known some of these ideas +like but I never really liked I'd read + + align:start position:0% +like but I never really liked I'd read + + + align:start position:0% +like but I never really liked I'd read +oh yeah they have you know they thought + + align:start position:0% +oh yeah they have you know they thought + + + align:start position:0% +oh yeah they have you know they thought +that the earth was the middle of the you + + align:start position:0% +that the earth was the middle of the you + + + align:start position:0% +that the earth was the middle of the you +know I'd never really thought about them + + align:start position:0% +know I'd never really thought about them + + + align:start position:0% +know I'd never really thought about them +and why you know I always thought of + + align:start position:0% +and why you know I always thought of + + + align:start position:0% +and why you know I always thought of +them as you know well we're more + + align:start position:0% +them as you know well we're more + + + align:start position:0% +them as you know well we're more +advanced than that we've gotten that + + align:start position:0% +advanced than that we've gotten that + + + align:start position:0% +advanced than that we've gotten that +idea but what I liked was that + + align:start position:0% +idea but what I liked was that + + + align:start position:0% +idea but what I liked was that +especially at the beginning of the + + align:start position:0% +especially at the beginning of the + + + align:start position:0% +especially at the beginning of the +heavens thing he sort of went you know + + align:start position:0% +heavens thing he sort of went you know + + + align:start position:0% +heavens thing he sort of went you know +well your idea you know the modern idea + + align:start position:0% +well your idea you know the modern idea + + + align:start position:0% +well your idea you know the modern idea +of how the laws of nature work are just + + align:start position:0% +of how the laws of nature work are just + + + align:start position:0% +of how the laws of nature work are just +as stupid as theirs you know no he + + align:start position:0% +as stupid as theirs you know no he + + + align:start position:0% +as stupid as theirs you know no he +doesn't say they're Or it's just it's + + align:start position:0% +doesn't say they're Or it's just it's + + + align:start position:0% +doesn't say they're Or it's just it's +not we're not you know it's not that the + + align:start position:0% +not we're not you know it's not that the + + + align:start position:0% +not we're not you know it's not that the +same way maybe it was that we're not + + align:start position:0% +same way maybe it was that we're not + + + align:start position:0% +same way maybe it was that we're not +like it sort of broke down that we are + + align:start position:0% +like it sort of broke down that we are + + + align:start position:0% +like it sort of broke down that we are +better than their ideas that you know + + align:start position:0% +better than their ideas that you know + + + align:start position:0% +better than their ideas that you know +why is it that our ideas that well you + + align:start position:0% +why is it that our ideas that well you + + + align:start position:0% +why is it that our ideas that well you +know these things are sentient beings + + align:start position:0% +know these things are sentient beings + + + align:start position:0% +know these things are sentient beings +that you know therefore can obey laws + + align:start position:0% +that you know therefore can obey laws + + + align:start position:0% +that you know therefore can obey laws +versus their ideas well they like each + + align:start position:0% +versus their ideas well they like each + + + align:start position:0% +versus their ideas well they like each +other and therefore they want to get to + + align:start position:0% +other and therefore they want to get to + + + align:start position:0% +other and therefore they want to get to +they want to get together right that's + + align:start position:0% +they want to get together right that's + + + align:start position:0% +they want to get together right that's +right you know okay so if I'm a stone + + align:start position:0% +right you know okay so if I'm a stone + + + align:start position:0% +right you know okay so if I'm a stone +I'm + + align:start position:0% +I'm + + + align:start position:0% +I'm +heavy and I desperately want to be where + + align:start position:0% +heavy and I desperately want to be where + + + align:start position:0% +heavy and I desperately want to be where +I belong long, which is on the earth. + + align:start position:0% +I belong long, which is on the earth. + + + align:start position:0% +I belong long, which is on the earth. +So, if somebody drops me off of a + + align:start position:0% +So, if somebody drops me off of a + + + align:start position:0% +So, if somebody drops me off of a +tower, I'm going to get as quickly as I + + align:start position:0% +tower, I'm going to get as quickly as I + + + align:start position:0% +tower, I'm going to get as quickly as I +possibly can back to Earth, which is + + align:start position:0% +possibly can back to Earth, which is + + + align:start position:0% +possibly can back to Earth, which is +down, right? Okay. And that's what I do + + align:start position:0% +down, right? Okay. And that's what I do + + + align:start position:0% +down, right? Okay. And that's what I do +if I'm a stone. Now, in our world, we + + align:start position:0% +if I'm a stone. Now, in our world, we + + + align:start position:0% +if I'm a stone. Now, in our world, we +have this thing called the law of + + align:start position:0% +have this thing called the law of + + + align:start position:0% +have this thing called the law of +gravity. And if I drop a stone off of a + + align:start position:0% +gravity. And if I drop a stone off of a + + + align:start position:0% +gravity. And if I drop a stone off of a +tower, the gravity police jump out, + + align:start position:0% +tower, the gravity police jump out, + + + align:start position:0% +tower, the gravity police jump out, +right? the way in the in the the + + align:start position:0% +right? the way in the in the the + + + align:start position:0% +right? the way in the in the the +metaphor that he uses, right? And you + + align:start position:0% +metaphor that he uses, right? And you + + + align:start position:0% +metaphor that he uses, right? And you +know, says, "Get thee down to that large + + align:start position:0% +know, says, "Get thee down to that large + + + align:start position:0% +know, says, "Get thee down to that large +mass," right? And off I go because I've + + align:start position:0% +mass," right? And off I go because I've + + + align:start position:0% +mass," right? And off I go because I've +been told that's what I'm supposed to + + align:start position:0% +been told that's what I'm supposed to + + + align:start position:0% +been told that's what I'm supposed to +do. I mean, the the passage is on 94. + + align:start position:0% +do. I mean, the the passage is on 94. + + + align:start position:0% +do. I mean, the the passage is on 94. +Um, but though neither statement can be + + align:start position:0% +Um, but though neither statement can be + + + align:start position:0% +Um, but though neither statement can be +taken literally, it does not follow that + + align:start position:0% +taken literally, it does not follow that + + + align:start position:0% +taken literally, it does not follow that +it makes no difference which is used. On + + align:start position:0% +it makes no difference which is used. On + + + align:start position:0% +it makes no difference which is used. On +the imaginative and emotional level, it + + align:start position:0% +the imaginative and emotional level, it + + + align:start position:0% +the imaginative and emotional level, it +makes a great difference whether with + + align:start position:0% +makes a great difference whether with + + + align:start position:0% +makes a great difference whether with +the medievalss we project upon the + + align:start position:0% +the medievalss we project upon the + + + align:start position:0% +the medievalss we project upon the +universe our strivings and desires or + + align:start position:0% +universe our strivings and desires or + + + align:start position:0% +universe our strivings and desires or +with the moderns, our police system and + + align:start position:0% +with the moderns, our police system and + + + align:start position:0% +with the moderns, our police system and +our traffic + + align:start position:0% +our traffic + + + align:start position:0% +our traffic +regulations. I mean, do you did you find + + align:start position:0% +regulations. I mean, do you did you find + + + align:start position:0% +regulations. I mean, do you did you find +that + + align:start position:0% +that + + + align:start position:0% +that +compelling? It's a kind of an upsetting + + align:start position:0% +compelling? It's a kind of an upsetting + + + align:start position:0% +compelling? It's a kind of an upsetting +way to think about gravity though, isn't + + align:start position:0% +way to think about gravity though, isn't + + + align:start position:0% +way to think about gravity though, isn't +it? + + align:start position:0% +it? + + + align:start position:0% +it? +Yes and no. But I mean I'm kind of torn + + align:start position:0% +Yes and no. But I mean I'm kind of torn + + + align:start position:0% +Yes and no. But I mean I'm kind of torn +as to whether or not + + align:start position:0% +as to whether or not + + + align:start position:0% +as to whether or not +to like initially I just think you know + + align:start position:0% +to like initially I just think you know + + + align:start position:0% +to like initially I just think you know +well that's kind of shallow assessment + + align:start position:0% +well that's kind of shallow assessment + + + align:start position:0% +well that's kind of shallow assessment +on his part of how we are looking at at + + align:start position:0% +on his part of how we are looking at at + + + align:start position:0% +on his part of how we are looking at at +something like that you know that well + + align:start position:0% +something like that you know that well + + + align:start position:0% +something like that you know that well +well you dummy you know that's not + + align:start position:0% +well you dummy you know that's not + + + align:start position:0% +well you dummy you know that's not +actually how we think about it + + align:start position:0% +actually how we think about it + + + align:start position:0% +actually how we think about it +but + + align:start position:0% +but + + + align:start position:0% +but +I I feel like if he'd made a case that + + align:start position:0% +I I feel like if he'd made a case that + + + align:start position:0% +I I feel like if he'd made a case that +you know because because a physicist + + align:start position:0% +you know because because a physicist + + + align:start position:0% +you know because because a physicist +doesn't really think that you know that + + align:start position:0% +doesn't really think that you know that + + + align:start position:0% +doesn't really think that you know that +that there's that something is obeying a + + align:start position:0% +that there's that something is obeying a + + + align:start position:0% +that there's that something is obeying a +law. It's that there is a set of + + align:start position:0% +law. It's that there is a set of + + + align:start position:0% +law. It's that there is a set of +mathematical equations which describe + + align:start position:0% +mathematical equations which describe + + + align:start position:0% +mathematical equations which describe +how something what something does what + + align:start position:0% +how something what something does what + + + align:start position:0% +how something what something does what +happens right not that it's but but then + + align:start position:0% +happens right not that it's but but then + + + align:start position:0% +happens right not that it's but but then +you know that's really you know people + + align:start position:0% +you know that's really you know people + + + align:start position:0% +you know that's really you know people +could have thought in in kind of similar + + align:start position:0% +could have thought in in kind of similar + + + align:start position:0% +could have thought in in kind of similar +there could have been more to what they + + align:start position:0% +there could have been more to what they + + + align:start position:0% +there could have been more to what they +were thinking in medieval times uh about + + align:start position:0% +were thinking in medieval times uh about + + + align:start position:0% +were thinking in medieval times uh about +the actions of things you know in in + + align:start position:0% +the actions of things you know in in + + + align:start position:0% +the actions of things you know in in +their their likes and dislikes they + + align:start position:0% +their their likes and dislikes they + + + align:start position:0% +their their likes and dislikes they +could have understood it and I he's kind + + align:start position:0% +could have understood it and I he's kind + + + align:start position:0% +could have understood it and I he's kind +of kind of alludes to the fact that they + + align:start position:0% +of kind of alludes to the fact that they + + + align:start position:0% +of kind of alludes to the fact that they +understood it better than that and just + + align:start position:0% +understood it better than that and just + + + align:start position:0% +understood it better than that and just +use that as allegory. Let me let me ask + + align:start position:0% +use that as allegory. Let me let me ask + + + align:start position:0% +use that as allegory. Let me let me ask +you a question about math. Mhm. + + align:start position:0% +you a question about math. Mhm. + + + align:start position:0% +you a question about math. Mhm. +Okay. And this is not this is not a + + align:start position:0% +Okay. And this is not this is not a + + + align:start position:0% +Okay. And this is not this is not a +question that that + + align:start position:0% +question that that + + + align:start position:0% +question that that +um the medieval man would ever have even + + align:start position:0% +um the medieval man would ever have even + + + align:start position:0% +um the medieval man would ever have even +had to have thought + + align:start position:0% +had to have thought + + + align:start position:0% +had to have thought +about. But I mean do you + + align:start position:0% +about. But I mean do you + + + align:start position:0% +about. But I mean do you +believe that math is + + align:start position:0% +believe that math is + + + align:start position:0% +believe that math is +true? Right? And by true I mean true + + align:start position:0% +true? Right? And by true I mean true + + + align:start position:0% +true? Right? And by true I mean true +with like a capital T. + + align:start position:0% +with like a capital T. + + + align:start position:0% +with like a capital T. +true for all time, for all place, + + align:start position:0% +true for all time, for all place, + + + align:start position:0% +true for all time, for all place, +because it's true and separate, right? + + align:start position:0% +because it's true and separate, right? + + + align:start position:0% +because it's true and separate, right? +Not true because I've figured it out and + + align:start position:0% +Not true because I've figured it out and + + + align:start position:0% +Not true because I've figured it out and +the formulas all line up together, okay? + + align:start position:0% +the formulas all line up together, okay? + + + align:start position:0% +the formulas all line up together, okay? +But true because it's really + + align:start position:0% +But true because it's really + + + align:start position:0% +But true because it's really +true. And + + align:start position:0% +true. And + + + align:start position:0% +true. And +therefore, when we figure out that + + align:start position:0% +therefore, when we figure out that + + + align:start position:0% +therefore, when we figure out that +gravity works in a certain way, and + + align:start position:0% +gravity works in a certain way, and + + + align:start position:0% +gravity works in a certain way, and +here's the mathematical formula, all + + align:start position:0% +here's the mathematical formula, all + + + align:start position:0% +here's the mathematical formula, all +we're doing is tapping into a truth + + align:start position:0% +we're doing is tapping into a truth + + + align:start position:0% +we're doing is tapping into a truth +that's already + + align:start position:0% +that's already + + + align:start position:0% +that's already +there. Do do you all believe that? Yeah, + + align:start position:0% +there. Do do you all believe that? Yeah, + + + align:start position:0% +there. Do do you all believe that? Yeah, +Peter. I mean, I view math more as a + + align:start position:0% +Peter. I mean, I view math more as a + + + align:start position:0% +Peter. I mean, I view math more as a +tool to create a model. I mean, I think + + align:start position:0% +tool to create a model. I mean, I think + + + align:start position:0% +tool to create a model. I mean, I think +I think Lewis makes the point somewhere + + align:start position:0% +I think Lewis makes the point somewhere + + + align:start position:0% +I think Lewis makes the point somewhere +that even, you know, up until the 1920s + + align:start position:0% +that even, you know, up until the 1920s + + + align:start position:0% +that even, you know, up until the 1920s +and 30s, we were still viewing a model + + align:start position:0% +and 30s, we were still viewing a model + + + align:start position:0% +and 30s, we were still viewing a model +we thought was true and then we started + + align:start position:0% +we thought was true and then we started + + + align:start position:0% +we thought was true and then we started +getting into quantum mechanics and that + + align:start position:0% +getting into quantum mechanics and that + + + align:start position:0% +getting into quantum mechanics and that +kind of changed our whole view of the + + align:start position:0% +kind of changed our whole view of the + + + align:start position:0% +kind of changed our whole view of the +earth. I mean, if you told someone in + + align:start position:0% +earth. I mean, if you told someone in + + + align:start position:0% +earth. I mean, if you told someone in +the 1900 that if you jump into a wall + + align:start position:0% +the 1900 that if you jump into a wall + + + align:start position:0% +the 1900 that if you jump into a wall +enough, you'd actually go through it at + + align:start position:0% +enough, you'd actually go through it at + + + align:start position:0% +enough, you'd actually go through it at +one point, you know, they wouldn't + + align:start position:0% +one point, you know, they wouldn't + + + align:start position:0% +one point, you know, they wouldn't +believe you. But it's I mean, it's just + + align:start position:0% +believe you. But it's I mean, it's just + + + align:start position:0% +believe you. But it's I mean, it's just +it's statistically possible to do + + align:start position:0% +it's statistically possible to do + + + align:start position:0% +it's statistically possible to do +something like that. But you can't + + align:start position:0% +something like that. But you can't + + + align:start position:0% +something like that. But you can't +really have a I mean the problem I have + + align:start position:0% +really have a I mean the problem I have + + + align:start position:0% +really have a I mean the problem I have +I mean in my in my experience that there + + align:start position:0% +I mean in my in my experience that there + + + align:start position:0% +I mean in my in my experience that there +is no model that will describe + + align:start position:0% +is no model that will describe + + + align:start position:0% +is no model that will describe +everything. There's just a whole bunch + + align:start position:0% +everything. There's just a whole bunch + + + align:start position:0% +everything. There's just a whole bunch +of tools that describe that thing. Kind + + align:start position:0% +of tools that describe that thing. Kind + + + align:start position:0% +of tools that describe that thing. Kind +of how Louis says that they had a whole + + align:start position:0% +of how Louis says that they had a whole + + + align:start position:0% +of how Louis says that they had a whole +bunch of observations and then they made + + align:start position:0% +bunch of observations and then they made + + + align:start position:0% +bunch of observations and then they made +a model that fit it and now we have a + + align:start position:0% +a model that fit it and now we have a + + + align:start position:0% +a model that fit it and now we have a +whole bunch of other rather bizarre you + + align:start position:0% +whole bunch of other rather bizarre you + + + align:start position:0% +whole bunch of other rather bizarre you +know things by classical physics + + align:start position:0% +know things by classical physics + + + align:start position:0% +know things by classical physics +standards that and you have to create a + + align:start position:0% +standards that and you have to create a + + + align:start position:0% +standards that and you have to create a +new model. So I don't think that there + + align:start position:0% +new model. So I don't think that there + + + align:start position:0% +new model. So I don't think that there +is any I don't think that math can be + + align:start position:0% +is any I don't think that math can be + + + align:start position:0% +is any I don't think that math can be +viewed as true. It's just a dummy. Okay. + + align:start position:0% +viewed as true. It's just a dummy. Okay. + + + align:start position:0% +viewed as true. It's just a dummy. Okay. +If you start from that position, then + + align:start position:0% +If you start from that position, then + + + align:start position:0% +If you start from that position, then +the medieval position is not hard to + + align:start position:0% +the medieval position is not hard to + + + align:start position:0% +the medieval position is not hard to +walk yourself into at all. Right? It's + + align:start position:0% +walk yourself into at all. Right? It's + + + align:start position:0% +walk yourself into at all. Right? It's +just working with a slightly different + + align:start position:0% +just working with a slightly different + + + align:start position:0% +just working with a slightly different +set of tools, a different set of + + align:start position:0% +set of tools, a different set of + + + align:start position:0% +set of tools, a different set of +authors, ancient authorities, etc. + + align:start position:0% +authors, ancient authorities, etc. + + + align:start position:0% +authors, ancient authorities, etc. +However, if you really believe that the + + align:start position:0% +However, if you really believe that the + + + align:start position:0% +However, if you really believe that the +math thing is true with a capital T, + + align:start position:0% +math thing is true with a capital T, + + + align:start position:0% +math thing is true with a capital T, +it's much harder to buy this, right? + + align:start position:0% +it's much harder to buy this, right? + + + align:start position:0% +it's much harder to buy this, right? +Then this then this is wrong in the + + align:start position:0% +Then this then this is wrong in the + + + align:start position:0% +Then this then this is wrong in the +capital W kind of a way, right? because + + align:start position:0% +capital W kind of a way, right? because + + + align:start position:0% +capital W kind of a way, right? because +the other thing is true and this isn't + + align:start position:0% +the other thing is true and this isn't + + + align:start position:0% +the other thing is true and this isn't +that and therefore it's a question of + + align:start position:0% +that and therefore it's a question of + + + align:start position:0% +that and therefore it's a question of +having missed the mark misunderstood the + + align:start position:0% +having missed the mark misunderstood the + + + align:start position:0% +having missed the mark misunderstood the +facts right not not tapped into um + + align:start position:0% +facts right not not tapped into um + + + align:start position:0% +facts right not not tapped into um +reality and and my guess is Peter that + + align:start position:0% +reality and and my guess is Peter that + + + align:start position:0% +reality and and my guess is Peter that +that your kind of ecumenical view on + + align:start position:0% +that your kind of ecumenical view on + + + align:start position:0% +that your kind of ecumenical view on +this is not widely shared around here um + + align:start position:0% +this is not widely shared around here um + + + align:start position:0% +this is not widely shared around here um +well at least in my well I'm not a + + align:start position:0% +well at least in my well I'm not a + + + align:start position:0% +well at least in my well I'm not a +physicist we kind of do fake physics in + + align:start position:0% +physicist we kind of do fake physics in + + + align:start position:0% +physicist we kind of do fake physics in +my department but you do fake physics + + align:start position:0% +my department but you do fake physics + + + align:start position:0% +my department but you do fake physics +you know, kind of priest. What were you + + align:start position:0% +you know, kind of priest. What were you + + + align:start position:0% +you know, kind of priest. What were you +going to say, Mon? I'm with him. + + align:start position:0% +going to say, Mon? I'm with him. + + + align:start position:0% +going to say, Mon? I'm with him. +I agree. I mean, math I mean, math is + + align:start position:0% +I agree. I mean, math I mean, math is + + + align:start position:0% +I agree. I mean, math I mean, math is +But there might be a reason you're all + + align:start position:0% +But there might be a reason you're all + + + align:start position:0% +But there might be a reason you're all +in this class. + + align:start position:0% +in this class. + + + align:start position:0% +in this class. +Yeah. Go ahead, Henry. And then Annie. + + align:start position:0% +Yeah. Go ahead, Henry. And then Annie. + + + align:start position:0% +Yeah. Go ahead, Henry. And then Annie. +No, I mean I'm a physicist and I don't + + align:start position:0% +No, I mean I'm a physicist and I don't + + + align:start position:0% +No, I mean I'm a physicist and I don't +think mathematics has an existence on + + align:start position:0% +think mathematics has an existence on + + + align:start position:0% +think mathematics has an existence on +its own. Okay. I don't I don't think + + align:start position:0% +its own. Okay. I don't I don't think + + + align:start position:0% +its own. Okay. I don't I don't think +it's like a being like you almost + + align:start position:0% +it's like a being like you almost + + + align:start position:0% +it's like a being like you almost +described it. Like it's not math doesn't + + align:start position:0% +described it. Like it's not math doesn't + + + align:start position:0% +described it. Like it's not math doesn't +exist without the models. Like I don't + + align:start position:0% +exist without the models. Like I don't + + + align:start position:0% +exist without the models. Like I don't +think I think actually most physicists + + align:start position:0% +think I think actually most physicists + + + align:start position:0% +think I think actually most physicists +now right if we could have caught them + + align:start position:0% +now right if we could have caught them + + + align:start position:0% +now right if we could have caught them +all what 25 years ago we would have + + align:start position:0% +all what 25 years ago we would have + + + align:start position:0% +all what 25 years ago we would have +gotten a slightly different + + align:start position:0% +gotten a slightly different + + + align:start position:0% +gotten a slightly different +answer right I I mean I think it's + + align:start position:0% +answer right I I mean I think it's + + + align:start position:0% +answer right I I mean I think it's +really + + align:start position:0% +really + + + align:start position:0% +really +changed people are a lot more + + align:start position:0% +changed people are a lot more + + + align:start position:0% +changed people are a lot more +comfortable with being less certain + + align:start position:0% +comfortable with being less certain + + + align:start position:0% +comfortable with being less certain +um but what were you going to say Annie + + align:start position:0% +um but what were you going to say Annie + + + align:start position:0% +um but what were you going to say Annie +well I don't know I guess I'm a freak of + + align:start position:0% +well I don't know I guess I'm a freak of + + + align:start position:0% +well I don't know I guess I'm a freak of +guru but I don't know I do sort of think + + align:start position:0% +guru but I don't know I do sort of think + + + align:start position:0% +guru but I don't know I do sort of think +math is true and that like one and one + + align:start position:0% +math is true and that like one and one + + + align:start position:0% +math is true and that like one and one +will always equal two. No matter what, + + align:start position:0% +will always equal two. No matter what, + + + align:start position:0% +will always equal two. No matter what, +no matter where you are, no matter what + + align:start position:0% +no matter where you are, no matter what + + + align:start position:0% +no matter where you are, no matter what +time you're in, one and one are always + + align:start position:0% +time you're in, one and one are always + + + align:start position:0% +time you're in, one and one are always +two. Never changes. And that like, yeah, + + align:start position:0% +two. Never changes. And that like, yeah, + + + align:start position:0% +two. Never changes. And that like, yeah, +our models change. Like, we're always + + align:start position:0% +our models change. Like, we're always + + + align:start position:0% +our models change. Like, we're always +learning new things, and we're always + + align:start position:0% +learning new things, and we're always + + + align:start position:0% +learning new things, and we're always +making better observations, coming up + + align:start position:0% +making better observations, coming up + + + align:start position:0% +making better observations, coming up +with new models, but presumably we're + + align:start position:0% +with new models, but presumably we're + + + align:start position:0% +with new models, but presumably we're +getting closer and closer to the truth, + + align:start position:0% +getting closer and closer to the truth, + + + align:start position:0% +getting closer and closer to the truth, +to the capital T. And so, I don't think + + align:start position:0% +to the capital T. And so, I don't think + + + align:start position:0% +to the capital T. And so, I don't think +I don't know. I don't think that the + + align:start position:0% +I don't know. I don't think that the + + + align:start position:0% +I don't know. I don't think that the +medieval way was necessarily wrong, + + align:start position:0% +medieval way was necessarily wrong, + + + align:start position:0% +medieval way was necessarily wrong, +right? because it was based on the + + align:start position:0% +right? because it was based on the + + + align:start position:0% +right? because it was based on the +observations they had like similar to + + align:start position:0% +observations they had like similar to + + + align:start position:0% +observations they had like similar to +what Peter thinks and now we have more + + align:start position:0% +what Peter thinks and now we have more + + + align:start position:0% +what Peter thinks and now we have more +observations and so we have a better + + align:start position:0% +observations and so we have a better + + + align:start position:0% +observations and so we have a better +model but you know who knows in 100 + + align:start position:0% +model but you know who knows in 100 + + + align:start position:0% +model but you know who knows in 100 +years we probably have something + + align:start position:0% +years we probably have something + + + align:start position:0% +years we probably have something +completely different than what we think + + align:start position:0% +completely different than what we think + + + align:start position:0% +completely different than what we think +now and quantum mechanics will be crazy + + align:start position:0% +now and quantum mechanics will be crazy + + + align:start position:0% +now and quantum mechanics will be crazy +and you know whatever they'll think we + + align:start position:0% +and you know whatever they'll think we + + + align:start position:0% +and you know whatever they'll think we +were all like + + align:start position:0% +were all like + + + align:start position:0% +were all like +and you know there'll be all those + + align:start position:0% +and you know there'll be all those + + + align:start position:0% +and you know there'll be all those +stupid people in the 20th century that + + align:start position:0% +stupid people in the 20th century that + + + align:start position:0% +stupid people in the 20th century that +thought that but I feel like we're + + align:start position:0% +thought that but I feel like we're + + + align:start position:0% +thought that but I feel like we're +getting closer somehow + + align:start position:0% +getting closer somehow + + + align:start position:0% +getting closer somehow +what were you going to say mom + + align:start position:0% +what were you going to say mom + + + align:start position:0% +what were you going to say mom +I forgot Okay, I've always I have a + + align:start position:0% +I forgot Okay, I've always I have a + + + align:start position:0% +I forgot Okay, I've always I have a +problem with you who say 1 + 1 equals 1 + + align:start position:0% +problem with you who say 1 + 1 equals 1 + + + align:start position:0% +problem with you who say 1 + 1 equals 1 +or 1 plus 1 equals 2 and in fact if you + + align:start position:0% +or 1 plus 1 equals 2 and in fact if you + + + align:start position:0% +or 1 plus 1 equals 2 and in fact if you +take a lot of people have been having + + align:start position:0% +take a lot of people have been having + + + align:start position:0% +take a lot of people have been having +sort of joking around if you take a lot + + align:start position:0% +sort of joking around if you take a lot + + + align:start position:0% +sort of joking around if you take a lot +of the mod you know the mathematical + + align:start position:0% +of the mod you know the mathematical + + + align:start position:0% +of the mod you know the mathematical +models you know x^2 x you know x= like + + align:start position:0% +models you know x^2 x you know x= like + + + align:start position:0% +models you know x^2 x you know x= like +you can you can prove things like 1 + + align:start position:0% +you can you can prove things like 1 + + + align:start position:0% +you can you can prove things like 1 +equals 2 and problematic and it's sort + + align:start position:0% +equals 2 and problematic and it's sort + + + align:start position:0% +equals 2 and problematic and it's sort +of problematic because by you you know + + align:start position:0% +of problematic because by you you know + + + align:start position:0% +of problematic because by you you know +manipulating these little x's and + + align:start position:0% +manipulating these little x's and + + + align:start position:0% +manipulating these little x's and +squares and you know square roots and + + align:start position:0% +squares and you know square roots and + + + align:start position:0% +squares and you know square roots and +stuff you can make things equal other + + align:start position:0% +stuff you can make things equal other + + + align:start position:0% +stuff you can make things equal other +things you know in you one cup plus two + + align:start position:0% +things you know in you one cup plus two + + + align:start position:0% +things you know in you one cup plus two +cups doesn't really, you know, it + + align:start position:0% +cups doesn't really, you know, it + + + align:start position:0% +cups doesn't really, you know, it +doesn't actually always equal three type + + align:start position:0% +doesn't actually always equal three type + + + align:start position:0% +doesn't actually always equal three type +of thing. And it's really weird because + + align:start position:0% +of thing. And it's really weird because + + + align:start position:0% +of thing. And it's really weird because +sounds like a faulty proof to me. + + align:start position:0% +sounds like a faulty proof to me. + + + align:start position:0% +sounds like a faulty proof to me. +What happens when you start dividing by + + align:start position:0% +What happens when you start dividing by + + + align:start position:0% +What happens when you start dividing by +zero? Yeah, it's easy enough to like I + + align:start position:0% +zero? Yeah, it's easy enough to like I + + + align:start position:0% +zero? Yeah, it's easy enough to like I +think therefore you can't take it as + + align:start position:0% +think therefore you can't take it as + + + align:start position:0% +think therefore you can't take it as +absolute fact because it's just gotten + + align:start position:0% +absolute fact because it's just gotten + + + align:start position:0% +absolute fact because it's just gotten +so complicated that you can manipulate + + align:start position:0% +so complicated that you can manipulate + + + align:start position:0% +so complicated that you can manipulate +it into whatever facts you want. But I + + align:start position:0% +it into whatever facts you want. But I + + + align:start position:0% +it into whatever facts you want. But I +mean I I I think that's kind of just + + align:start position:0% +mean I I I think that's kind of just + + + align:start position:0% +mean I I I think that's kind of just +because you can manipulate it in a + + align:start position:0% +because you can manipulate it in a + + + align:start position:0% +because you can manipulate it in a +fashion that is against the rules. I + + align:start position:0% +fashion that is against the rules. I + + + align:start position:0% +fashion that is against the rules. I +mean, just because someone who doesn't + + align:start position:0% +mean, just because someone who doesn't + + + align:start position:0% +mean, just because someone who doesn't +necessarily know all the rules can can + + align:start position:0% +necessarily know all the rules can can + + + align:start position:0% +necessarily know all the rules can can +can misunderstand it, I don't think + + align:start position:0% +can misunderstand it, I don't think + + + align:start position:0% +can misunderstand it, I don't think +makes it necessarily valable. Jump in, + + align:start position:0% +makes it necessarily valable. Jump in, + + + align:start position:0% +makes it necessarily valable. Jump in, +Nick. Um, I mean, I kind of agree with + + align:start position:0% +Nick. Um, I mean, I kind of agree with + + + align:start position:0% +Nick. Um, I mean, I kind of agree with +Annie. Like, I think there's like + + align:start position:0% +Annie. Like, I think there's like + + + align:start position:0% +Annie. Like, I think there's like +especially arithmetic, like I think I'm + + align:start position:0% +especially arithmetic, like I think I'm + + + align:start position:0% +especially arithmetic, like I think I'm +kind of believer 1 plus one's always + + align:start position:0% +kind of believer 1 plus one's always + + + align:start position:0% +kind of believer 1 plus one's always +going to equal two. Like, I've seen some + + align:start position:0% +going to equal two. Like, I've seen some + + + align:start position:0% +going to equal two. Like, I've seen some +guys prove that it doesn't, but I don't. + + align:start position:0% +guys prove that it doesn't, but I don't. + + + align:start position:0% +guys prove that it doesn't, but I don't. +And, uh, like also I think geometry has + + align:start position:0% +And, uh, like also I think geometry has + + + align:start position:0% +And, uh, like also I think geometry has +some like innately true properties like + + align:start position:0% +some like innately true properties like + + + align:start position:0% +some like innately true properties like +circles and triangles. I think there's + + align:start position:0% +circles and triangles. I think there's + + + align:start position:0% +circles and triangles. I think there's +some things there that no matter where + + align:start position:0% +some things there that no matter where + + + align:start position:0% +some things there that no matter where +you find them, they'll always be the + + align:start position:0% +you find them, they'll always be the + + + align:start position:0% +you find them, they'll always be the +same. You know, like if an angle is an + + align:start position:0% +same. You know, like if an angle is an + + + align:start position:0% +same. You know, like if an angle is an +angle, stuff like that. Well, geometry + + align:start position:0% +angle, stuff like that. Well, geometry + + + align:start position:0% +angle, stuff like that. Well, geometry +is a problem. The Greeks can never tie + + align:start position:0% +is a problem. The Greeks can never tie + + + align:start position:0% +is a problem. The Greeks can never tie +an angle. I mean, they just couldn't. I + + align:start position:0% +an angle. I mean, they just couldn't. I + + + align:start position:0% +an angle. I mean, they just couldn't. I +mean, you could think that you could + + align:start position:0% +mean, you could think that you could + + + align:start position:0% +mean, you could think that you could +split an angle into three equal parts, + + align:start position:0% +split an angle into three equal parts, + + + align:start position:0% +split an angle into three equal parts, +but you can't. I mean, using geometric + + align:start position:0% +but you can't. I mean, using geometric + + + align:start position:0% +but you can't. I mean, using geometric +constructs is impossible. I mean, + + align:start position:0% +constructs is impossible. I mean, + + + align:start position:0% +constructs is impossible. I mean, +everything you do in math is based on a + + align:start position:0% +everything you do in math is based on a + + + align:start position:0% +everything you do in math is based on a +certain set of assumptions just like + + align:start position:0% +certain set of assumptions just like + + + align:start position:0% +certain set of assumptions just like +everything we do in physics. I mean, all + + align:start position:0% +everything we do in physics. I mean, all + + + align:start position:0% +everything we do in physics. I mean, all +quantum mechanics is based + + align:start position:0% +quantum mechanics is based + + + align:start position:0% +quantum mechanics is based +on some number of postulates. Mhm. Yeah. + + align:start position:0% +on some number of postulates. Mhm. Yeah. + + + align:start position:0% +on some number of postulates. Mhm. Yeah. +Yeah, I forgot the number. But I mean + + align:start position:0% +Yeah, I forgot the number. But I mean + + + align:start position:0% +Yeah, I forgot the number. But I mean +there's a whole I mean it's all based on + + align:start position:0% +there's a whole I mean it's all based on + + + align:start position:0% +there's a whole I mean it's all based on +what you think is true. You can do + + align:start position:0% +what you think is true. You can do + + + align:start position:0% +what you think is true. You can do +non-ucukitian geometry and just + + align:start position:0% +non-ucukitian geometry and just + + + align:start position:0% +non-ucukitian geometry and just +completely throw everything that you + + align:start position:0% +completely throw everything that you + + + align:start position:0% +completely throw everything that you +know about classical geometry out the + + align:start position:0% +know about classical geometry out the + + + align:start position:0% +know about classical geometry out the +window. And I mean if you know Uklid + + align:start position:0% +window. And I mean if you know Uklid + + + align:start position:0% +window. And I mean if you know Uklid +believed one thing based on his set of + + align:start position:0% +believed one thing based on his set of + + + align:start position:0% +believed one thing based on his set of +assumptions, but you know anti-uclid can + + align:start position:0% +assumptions, but you know anti-uclid can + + + align:start position:0% +assumptions, but you know anti-uclid can +you know get completely different + + align:start position:0% +you know get completely different + + + align:start position:0% +you know get completely different +results. Let me let me let me ask a a + + align:start position:0% +results. Let me let me let me ask a a + + + align:start position:0% +results. Let me let me let me ask a a +slightly different question but that I + + align:start position:0% +slightly different question but that I + + + align:start position:0% +slightly different question but that I +think will still keep us thinking about + + align:start position:0% +think will still keep us thinking about + + + align:start position:0% +think will still keep us thinking about +this set of problems. If Lewis is right + + align:start position:0% +this set of problems. If Lewis is right + + + align:start position:0% +this set of problems. If Lewis is right +and that what the and that we could + + align:start position:0% +and that what the and that we could + + + align:start position:0% +and that what the and that we could +characterize sort of the general + + align:start position:0% +characterize sort of the general + + + align:start position:0% +characterize sort of the general +medieval mindset as having a couple of + + align:start position:0% +medieval mindset as having a couple of + + + align:start position:0% +medieval mindset as having a couple of +characteristics. One, it's bookish, + + align:start position:0% +characteristics. One, it's bookish, + + + align:start position:0% +characteristics. One, it's bookish, +right? He claims that in no uncertain + + align:start position:0% +right? He claims that in no uncertain + + + align:start position:0% +right? He claims that in no uncertain +terms. It wants to believe everything, + + align:start position:0% +terms. It wants to believe everything, + + + align:start position:0% +terms. It wants to believe everything, +right, that's ever been written by an + + align:start position:0% +right, that's ever been written by an + + + align:start position:0% +right, that's ever been written by an +authority. It's + + align:start position:0% +authority. It's + + + align:start position:0% +authority. It's +systematic, right? it wants to take all + + align:start position:0% +systematic, right? it wants to take all + + + align:start position:0% +systematic, right? it wants to take all +of the different things that it's read + + align:start position:0% +of the different things that it's read + + + align:start position:0% +of the different things that it's read +and somehow make sense of them. So he + + align:start position:0% +and somehow make sense of them. So he + + + align:start position:0% +and somehow make sense of them. So he +says, right, if there was an invention + + align:start position:0% +says, right, if there was an invention + + + align:start position:0% +says, right, if there was an invention +they would have really appreciated, it + + align:start position:0% +they would have really appreciated, it + + + align:start position:0% +they would have really appreciated, it +was the card index. That's a really + + align:start position:0% +was the card index. That's a really + + + align:start position:0% +was the card index. That's a really +great line. Um that's a that's a + + align:start position:0% +great line. Um that's a that's a + + + align:start position:0% +great line. Um that's a that's a +wonderful line. + + align:start position:0% +wonderful line. + + + align:start position:0% +wonderful line. +uh if it is those + + align:start position:0% +uh if it is those + + + align:start position:0% +uh if it is those +things and we know that there's all of + + align:start position:0% +things and we know that there's all of + + + align:start position:0% +things and we know that there's all of +this sort of competing information + + align:start position:0% +this sort of competing information + + + align:start position:0% +this sort of competing information +that's out there. You we're struggling + + align:start position:0% +that's out there. You we're struggling + + + align:start position:0% +that's out there. You we're struggling +right now with some competing + + align:start position:0% +right now with some competing + + + align:start position:0% +right now with some competing +information right in our own um uh sort + + align:start position:0% +information right in our own um uh sort + + + align:start position:0% +information right in our own um uh sort +of niche of the cosmological project. + + align:start position:0% + + + + align:start position:0% + +um where what where does that leave a + + align:start position:0% +um where what where does that leave a + + + align:start position:0% +um where what where does that leave a +medieval thinker right if they if Lewis + + align:start position:0% +medieval thinker right if they if Lewis + + + align:start position:0% +medieval thinker right if they if Lewis +is right and they're compelled right to + + align:start position:0% +is right and they're compelled right to + + + align:start position:0% +is right and they're compelled right to +be + + align:start position:0% +be + + + align:start position:0% +be +systematic and eclectic although they + + align:start position:0% +systematic and eclectic although they + + + align:start position:0% +systematic and eclectic although they +might not have seen it that way and to + + align:start position:0% +might not have seen it that way and to + + + align:start position:0% +might not have seen it that way and to +believe all authorities whether they're + + align:start position:0% +believe all authorities whether they're + + + align:start position:0% +believe all authorities whether they're +pagan or Christian or poetry or you know + + align:start position:0% +pagan or Christian or poetry or you know + + + align:start position:0% +pagan or Christian or poetry or you know +history or chronicle or whatever + + align:start position:0% +history or chronicle or whatever + + + align:start position:0% +history or chronicle or whatever +If I have to take all of this stuff and + + align:start position:0% +If I have to take all of this stuff and + + + align:start position:0% +If I have to take all of this stuff and +somehow make sense of it, where does + + align:start position:0% +somehow make sense of it, where does + + + align:start position:0% +somehow make sense of it, where does +that leave + + align:start position:0% +that leave + + + align:start position:0% +that leave +me? I mean, Lewis might just be + + align:start position:0% +me? I mean, Lewis might just be + + + align:start position:0% +me? I mean, Lewis might just be +wrong. That's one possibility. + + align:start position:0% + + + + align:start position:0% + +Multiple personalities. + + align:start position:0% +Multiple personalities. + + + align:start position:0% +Multiple personalities. +[Laughter] + + align:start position:0% +[Laughter] + + + align:start position:0% +[Laughter] +Okay. A lot of demented individuals of + + align:start position:0% +Okay. A lot of demented individuals of + + + align:start position:0% +Okay. A lot of demented individuals of +which we read, you know, last week. I + + align:start position:0% +which we read, you know, last week. I + + + align:start position:0% +which we read, you know, last week. I +don't think that was why they were + + align:start position:0% +don't think that was why they were + + + align:start position:0% +don't think that was why they were +demented, though. Ian, I I think that + + align:start position:0% +demented, though. Ian, I I think that + + + align:start position:0% +demented, though. Ian, I I think that +the the kind of naive belief of anyone + + align:start position:0% +the the kind of naive belief of anyone + + + align:start position:0% +the the kind of naive belief of anyone +presuming to be in authority is is, you + + align:start position:0% +presuming to be in authority is is, you + + + align:start position:0% +presuming to be in authority is is, you +know, is just that is rather naive and + + align:start position:0% +know, is just that is rather naive and + + + align:start position:0% +know, is just that is rather naive and +and kind of results in I'd like to think + + align:start position:0% +and kind of results in I'd like to think + + + align:start position:0% +and kind of results in I'd like to think +that that if there's any one thing that + + align:start position:0% +that that if there's any one thing that + + + align:start position:0% +that that if there's any one thing that +we now do better than than they might + + align:start position:0% +we now do better than than they might + + + align:start position:0% +we now do better than than they might +have done, it's, you know, + + align:start position:0% +have done, it's, you know, + + + align:start position:0% +have done, it's, you know, +valuing certain authorities over others, + + align:start position:0% +valuing certain authorities over others, + + + align:start position:0% +valuing certain authorities over others, +you know, or or weighing the weighing + + align:start position:0% +you know, or or weighing the weighing + + + align:start position:0% +you know, or or weighing the weighing +the value of certain things over others, + + align:start position:0% +the value of certain things over others, + + + align:start position:0% +the value of certain things over others, +not just on the basis of how interesting + + align:start position:0% +not just on the basis of how interesting + + + align:start position:0% +not just on the basis of how interesting +it is or how compelling they wrote. Mhm. + + align:start position:0% +it is or how compelling they wrote. Mhm. + + + align:start position:0% +it is or how compelling they wrote. Mhm. +Uh but + + align:start position:0% +Uh but + + + align:start position:0% +Uh but +it's I don't know. I I I think that's + + align:start position:0% +it's I don't know. I I I think that's + + + align:start position:0% +it's I don't know. I I I think that's +the may + + align:start position:0% +the may + + + align:start position:0% +the may +maybe I guess I'm not really answering + + align:start position:0% +maybe I guess I'm not really answering + + + align:start position:0% +maybe I guess I'm not really answering +the question, but that was just my the + + align:start position:0% +the question, but that was just my the + + + align:start position:0% +the question, but that was just my the +one thing you made me think about was + + align:start position:0% +one thing you made me think about was + + + align:start position:0% +one thing you made me think about was +that + + align:start position:0% + + + + align:start position:0% + +they're I think they just they ended up + + align:start position:0% +they're I think they just they ended up + + + align:start position:0% +they're I think they just they ended up +getting muddling a lot of things + + align:start position:0% +getting muddling a lot of things + + + align:start position:0% +getting muddling a lot of things +together simply based on the fact that + + align:start position:0% +together simply based on the fact that + + + align:start position:0% +together simply based on the fact that +they're willing to take poets as + + align:start position:0% +they're willing to take poets as + + + align:start position:0% +they're willing to take poets as +scientific authorities, things like that + + align:start position:0% +scientific authorities, things like that + + + align:start position:0% +scientific authorities, things like that +that they Well, I mean, are they + + align:start position:0% +that they Well, I mean, are they + + + align:start position:0% +that they Well, I mean, are they +actually willing to take poets as + + align:start position:0% +actually willing to take poets as + + + align:start position:0% +actually willing to take poets as +scientific + + align:start position:0% +scientific + + + align:start position:0% +scientific +authorities? Is that or are they quote + + align:start position:0% +authorities? Is that or are they quote + + + align:start position:0% +authorities? Is that or are they quote +unquote scientific authority or is there + + align:start position:0% +unquote scientific authority or is there + + + align:start position:0% +unquote scientific authority or is there +a distinction? Well, I mean there was + + align:start position:0% +a distinction? Well, I mean there was + + + align:start position:0% +a distinction? Well, I mean there was +much less of I mean the poets wrote a + + align:start position:0% +much less of I mean the poets wrote a + + + align:start position:0% +much less of I mean the poets wrote a +lot about science whereas you don't see + + align:start position:0% +lot about science whereas you don't see + + + align:start position:0% +lot about science whereas you don't see +many poets writing about our model of + + align:start position:0% +many poets writing about our model of + + + align:start position:0% +many poets writing about our model of +the universe. I mean + + align:start position:0% +the universe. I mean + + + align:start position:0% +the universe. I mean +oh here I had to take this class with + + align:start position:0% +oh here I had to take this class with + + + align:start position:0% +oh here I had to take this class with +John Hilder and we read this book about + + align:start position:0% +John Hilder and we read this book about + + + align:start position:0% +John Hilder and we read this book about +astrophysical poetry. I thought I was + + align:start position:0% +astrophysical poetry. I thought I was + + + align:start position:0% +astrophysical poetry. I thought I was +going to a lot I clarified that with a + + align:start position:0% +going to a lot I clarified that with a + + + align:start position:0% +going to a lot I clarified that with a +lot of people. Yeah. People race sonnets + + align:start position:0% +lot of people. Yeah. People race sonnets + + + align:start position:0% +lot of people. Yeah. People race sonnets +and 3091. It's you know they're not very + + align:start position:0% +and 3091. It's you know they're not very + + + align:start position:0% +and 3091. It's you know they're not very +pretty. I think I think there's a wider + + align:start position:0% +pretty. I think I think there's a wider + + + align:start position:0% +pretty. I think I think there's a wider +divide. I mean, I think what he saying + + align:start position:0% +divide. I mean, I think what he saying + + + align:start position:0% +divide. I mean, I think what he saying +is probably just a wider divide now + + align:start position:0% +is probably just a wider divide now + + + align:start position:0% +is probably just a wider divide now +between the authorities than there was + + align:start position:0% +between the authorities than there was + + + align:start position:0% +between the authorities than there was +back then that poets had a better maybe + + align:start position:0% +back then that poets had a better maybe + + + align:start position:0% +back then that poets had a better maybe +they had a better understanding of their + + align:start position:0% +they had a better understanding of their + + + align:start position:0% +they had a better understanding of their +model or it was much more accessible to + + align:start position:0% +model or it was much more accessible to + + + align:start position:0% +model or it was much more accessible to +them than our model is today. So it's + + align:start position:0% +them than our model is today. So it's + + + align:start position:0% +them than our model is today. So it's +harder for but it's Lewis then being + + align:start position:0% +harder for but it's Lewis then being + + + align:start position:0% +harder for but it's Lewis then being +inconsistent when he tells us which he + + align:start position:0% +inconsistent when he tells us which he + + + align:start position:0% +inconsistent when he tells us which he +does in no uncertain terms that theology + + align:start position:0% +does in no uncertain terms that theology + + + align:start position:0% +does in no uncertain terms that theology +right spiritual advice all that stuff is + + align:start position:0% +right spiritual advice all that stuff is + + + align:start position:0% +right spiritual advice all that stuff is +in fact separate from the general + + align:start position:0% +in fact separate from the general + + + align:start position:0% +in fact separate from the general +cultural + + align:start position:0% +cultural + + + align:start position:0% +cultural +model. I mean how do we square that? + + align:start position:0% +model. I mean how do we square that? + + + align:start position:0% +model. I mean how do we square that? +Well kind of makes sense. I mean think + + align:start position:0% +Well kind of makes sense. I mean think + + + align:start position:0% +Well kind of makes sense. I mean think +about how many scientists are Christians + + align:start position:0% +about how many scientists are Christians + + + align:start position:0% +about how many scientists are Christians +right? like you know you're a scientist + + align:start position:0% +right? like you know you're a scientist + + + align:start position:0% +right? like you know you're a scientist +and you you know you go to church and + + align:start position:0% +and you you know you go to church and + + + align:start position:0% +and you you know you go to church and +one day and you believe that God created + + align:start position:0% +one day and you believe that God created + + + align:start position:0% +one day and you believe that God created +the world in seven days but then on + + align:start position:0% +the world in seven days but then on + + + align:start position:0% +the world in seven days but then on +Monday you go to like your work and you + + align:start position:0% +Monday you go to like your work and you + + + align:start position:0% +Monday you go to like your work and you +believe in evolution and but that's not + + align:start position:0% +believe in evolution and but that's not + + + align:start position:0% +believe in evolution and but that's not +the claim exactly that Lewis is making + + align:start position:0% +the claim exactly that Lewis is making + + + align:start position:0% +the claim exactly that Lewis is making +right I mean he says oh go ahead just in + + align:start position:0% +right I mean he says oh go ahead just in + + + align:start position:0% +right I mean he says oh go ahead just in +terms of religion it makes sense because + + align:start position:0% +terms of religion it makes sense because + + + align:start position:0% +terms of religion it makes sense because +all I mean before I mean when you're + + align:start position:0% +all I mean before I mean when you're + + + align:start position:0% +all I mean before I mean when you're +looking at the pagan religions it's a + + align:start position:0% +looking at the pagan religions it's a + + + align:start position:0% +looking at the pagan religions it's a +nature is a big part of the religion you + + align:start position:0% +nature is a big part of the religion you + + + align:start position:0% +nature is a big part of the religion you +can't it's very hard to separate the + + align:start position:0% +can't it's very hard to separate the + + + align:start position:0% +can't it's very hard to separate the +world that exists from the theology that + + align:start position:0% +world that exists from the theology that + + + align:start position:0% +world that exists from the theology that +exists. On the other hand, with + + align:start position:0% +exists. On the other hand, with + + + align:start position:0% +exists. On the other hand, with +religions like Christianity, they're + + align:start position:0% +religions like Christianity, they're + + + align:start position:0% +religions like Christianity, they're +they are removed from the natural world. + + align:start position:0% +they are removed from the natural world. + + + align:start position:0% +they are removed from the natural world. +So, it's easier to it's easier to see + + align:start position:0% +So, it's easier to it's easier to see + + + align:start position:0% +So, it's easier to it's easier to see +that there was that there could have + + align:start position:0% +that there was that there could have + + + align:start position:0% +that there was that there could have +that people who were both Christians + + align:start position:0% +that people who were both Christians + + + align:start position:0% +that people who were both Christians +could see both the natural world and the + + align:start position:0% +could see both the natural world and the + + + align:start position:0% +could see both the natural world and the +theological world as two separate things + + align:start position:0% +theological world as two separate things + + + align:start position:0% +theological world as two separate things +because they don't really interact that + + align:start position:0% +because they don't really interact that + + + align:start position:0% +because they don't really interact that +much. + + align:start position:0% +much. + + + align:start position:0% +much. +But I think we're talking more + + align:start position:0% +But I think we're talking more + + + align:start position:0% +But I think we're talking more +about almost like a psychological + + align:start position:0% +about almost like a psychological + + + align:start position:0% +about almost like a psychological +divide. I mean, there's it's almost as + + align:start position:0% +divide. I mean, there's it's almost as + + + align:start position:0% +divide. I mean, there's it's almost as +if when you're thinking about + + align:start position:0% +if when you're thinking about + + + align:start position:0% +if when you're thinking about +one, you're just completely ignoring the + + align:start position:0% +one, you're just completely ignoring the + + + align:start position:0% +one, you're just completely ignoring the +other, right? But is that like I mean I + + align:start position:0% +other, right? But is that like I mean I + + + align:start position:0% +other, right? But is that like I mean I +mean I'm very much non-religious person, + + align:start position:0% +mean I'm very much non-religious person, + + + align:start position:0% +mean I'm very much non-religious person, +but it sounds like a lot of it is very + + align:start position:0% +but it sounds like a lot of it is very + + + align:start position:0% +but it sounds like a lot of it is very +much of the Christianity stuff is that + + align:start position:0% +much of the Christianity stuff is that + + + align:start position:0% +much of the Christianity stuff is that +there's, you know, there's heaven and + + align:start position:0% +there's, you know, there's heaven and + + + align:start position:0% +there's, you know, there's heaven and +there's hell, but earth is just + + align:start position:0% +there's hell, but earth is just + + + align:start position:0% +there's hell, but earth is just +something you deal with while you're, + + align:start position:0% +something you deal with while you're, + + + align:start position:0% +something you deal with while you're, +you know, trying to work away your sins + + align:start position:0% +you know, trying to work away your sins + + + align:start position:0% +you know, trying to work away your sins +and to get to heaven. And so figuring + + align:start position:0% +and to get to heaven. And so figuring + + + align:start position:0% +and to get to heaven. And so figuring +out how earth works isn't really what + + align:start position:0% +out how earth works isn't really what + + + align:start position:0% +out how earth works isn't really what +you know something to do with religion. + + align:start position:0% +you know something to do with religion. + + + align:start position:0% +you know something to do with religion. +It's more your own moralistic stuff + + align:start position:0% +It's more your own moralistic stuff + + + align:start position:0% +It's more your own moralistic stuff +that's dealing with it and then dealing + + align:start position:0% +that's dealing with it and then dealing + + + align:start position:0% +that's dealing with it and then dealing +with then figuring that out is separate + + align:start position:0% +with then figuring that out is separate + + + align:start position:0% +with then figuring that out is separate +than that. Go ahead. But now I have to + + align:start position:0% +than that. Go ahead. But now I have to + + + align:start position:0% +than that. Go ahead. But now I have to +think of this one passage where they + + align:start position:0% +think of this one passage where they + + + align:start position:0% +think of this one passage where they +talk about being in a the earth being + + align:start position:0% +talk about being in a the earth being + + + align:start position:0% +talk about being in a the earth being +the center of the universe, right? + + align:start position:0% +the center of the universe, right? + + + align:start position:0% +the center of the universe, right? +Thinking of a Mhm. that but then on then + + align:start position:0% +Thinking of a Mhm. that but then on then + + + align:start position:0% +Thinking of a Mhm. that but then on then +there's this passage which states you're + + align:start position:0% +there's this passage which states you're + + + align:start position:0% +there's this passage which states you're +outside the city walls. Yes. So I think + + align:start position:0% +outside the city walls. Yes. So I think + + + align:start position:0% +outside the city walls. Yes. So I think +here we have this kind of fundamental + + align:start position:0% +here we have this kind of fundamental + + + align:start position:0% +here we have this kind of fundamental +justosition where these two conflict + + align:start position:0% +justosition where these two conflict + + + align:start position:0% +justosition where these two conflict +because in one way yes God is the center + + align:start position:0% +because in one way yes God is the center + + + align:start position:0% +because in one way yes God is the center +and is the light and in this other way + + align:start position:0% +and is the light and in this other way + + + align:start position:0% +and is the light and in this other way +which puts us at the periphery but in in + + align:start position:0% +which puts us at the periphery but in in + + + align:start position:0% +which puts us at the periphery but in in +the model we are at the center and so I + + align:start position:0% +the model we are at the center and so I + + + align:start position:0% +the model we are at the center and so I +mean there there has to be some exchange + + align:start position:0% +mean there there has to be some exchange + + + align:start position:0% +mean there there has to be some exchange +of then he does explain how they're + + align:start position:0% +of then he does explain how they're + + + align:start position:0% +of then he does explain how they're +trying to reconcile this that we're + + align:start position:0% +trying to reconcile this that we're + + + align:start position:0% +trying to reconcile this that we're +actually looking inward and therefore we + + align:start position:0% +actually looking inward and therefore we + + + align:start position:0% +actually looking inward and therefore we +are at the center but we really are not. + + align:start position:0% +are at the center but we really are not. + + + align:start position:0% +are at the center but we really are not. +So, I mean, I think there was conflict + + align:start position:0% +So, I mean, I think there was conflict + + + align:start position:0% +So, I mean, I think there was conflict +in people's minds that they were trying + + align:start position:0% +in people's minds that they were trying + + + align:start position:0% +in people's minds that they were trying +to to decide what what was right. They + + align:start position:0% +to to decide what what was right. They + + + align:start position:0% +to to decide what what was right. They +were not divorcing the two entirely. + + align:start position:0% +were not divorcing the two entirely. + + + align:start position:0% +were not divorcing the two entirely. +Well, he let's let's go back to Lewis's + + align:start position:0% +Well, he let's let's go back to Lewis's + + + align:start position:0% +Well, he let's let's go back to Lewis's +argument because it's a it is a + + align:start position:0% +argument because it's a it is a + + + align:start position:0% +argument because it's a it is a +complicated one. It starts I mean it + + align:start position:0% +complicated one. It starts I mean it + + + align:start position:0% +complicated one. It starts I mean it +goes through the whole book really, + + align:start position:0% +goes through the whole book really, + + + align:start position:0% +goes through the whole book really, +right? But it's he lays it out first um + + align:start position:0% +right? But it's he lays it out first um + + + align:start position:0% +right? But it's he lays it out first um +starting on page 18 and he says he he + + align:start position:0% +starting on page 18 and he says he he + + + align:start position:0% +starting on page 18 and he says he he +opens up a space for himself to be + + align:start position:0% +opens up a space for himself to be + + + align:start position:0% +opens up a space for himself to be +contradictory essentially by saying one + + align:start position:0% +contradictory essentially by saying one + + + align:start position:0% +contradictory essentially by saying one +particular class of experts the great + + align:start position:0% +particular class of experts the great + + + align:start position:0% +particular class of experts the great +spiritual writers ignore the model + + align:start position:0% +spiritual writers ignore the model + + + align:start position:0% +spiritual writers ignore the model +almost completely. We need to know + + align:start position:0% +almost completely. We need to know + + + align:start position:0% +almost completely. We need to know +something about the model if we're to + + align:start position:0% +something about the model if we're to + + + align:start position:0% +something about the model if we're to +read Chaucer but we can neglect it if + + align:start position:0% +read Chaucer but we can neglect it if + + + align:start position:0% +read Chaucer but we can neglect it if +we're going to read St. Bernard right or + + align:start position:0% +we're going to read St. Bernard right or + + + align:start position:0% +we're going to read St. Bernard right or +the imitation of Christ or blah blah + + align:start position:0% +the imitation of Christ or blah blah + + + align:start position:0% +the imitation of Christ or blah blah +blah. He gives all these possibilities. + + align:start position:0% +blah. He gives all these possibilities. + + + align:start position:0% +blah. He gives all these possibilities. +Um so that's one way of dealing with + + align:start position:0% +Um so that's one way of dealing with + + + align:start position:0% +Um so that's one way of dealing with +this is saying even though the model + + align:start position:0% +this is saying even though the model + + + align:start position:0% +this is saying even though the model +looks to be intensely religious right + + align:start position:0% +looks to be intensely religious right + + + align:start position:0% +looks to be intensely religious right +the spheres the intelligences + + align:start position:0% +the spheres the intelligences + + + align:start position:0% +the spheres the intelligences +um the inclining because of the love of + + align:start position:0% +um the inclining because of the love of + + + align:start position:0% +um the inclining because of the love of +God the primum mobile why is the primo + + align:start position:0% +God the primum mobile why is the primo + + + align:start position:0% +God the primum mobile why is the primo +mobile even moving well because it loves + + align:start position:0% +mobile even moving well because it loves + + + align:start position:0% +mobile even moving well because it loves +God so much right and because it loves + + align:start position:0% +God so much right and because it loves + + + align:start position:0% +God so much right and because it loves +God so much it has to move and in what + + align:start position:0% +God so much it has to move and in what + + + align:start position:0% +God so much it has to move and in what +direction does it move it's perfect love + + align:start position:0% +direction does it move it's perfect love + + + align:start position:0% +direction does it move it's perfect love +after all so it moves in a circle right + + align:start position:0% +after all so it moves in a circle right + + + align:start position:0% +after all so it moves in a circle right +isn't Isn't this obvious that this would + + align:start position:0% +isn't Isn't this obvious that this would + + + align:start position:0% +isn't Isn't this obvious that this would +be how it would work? I mean, all of + + align:start position:0% +be how it would work? I mean, all of + + + align:start position:0% +be how it would work? I mean, all of +that sounds to us kind of + + align:start position:0% +that sounds to us kind of + + + align:start position:0% +that sounds to us kind of +religious, right? If we if we had to + + align:start position:0% +religious, right? If we if we had to + + + align:start position:0% +religious, right? If we if we had to +just sort of read it casually and + + align:start position:0% +just sort of read it casually and + + + align:start position:0% +just sort of read it casually and +classify it now, we'd say, "Oh, wow. + + align:start position:0% +classify it now, we'd say, "Oh, wow. + + + align:start position:0% +classify it now, we'd say, "Oh, wow. +What a lot of religious superstition." + + align:start position:0% +What a lot of religious superstition." + + + align:start position:0% +What a lot of religious superstition." +And by the same token, it seems like a + + align:start position:0% +And by the same token, it seems like a + + + align:start position:0% +And by the same token, it seems like a +lot of the spirit the great spiritual + + align:start position:0% +lot of the spirit the great spiritual + + + align:start position:0% +lot of the spirit the great spiritual +writers he cites I mean I wouldn't be + + align:start position:0% +writers he cites I mean I wouldn't be + + + align:start position:0% +writers he cites I mean I wouldn't be +surprised if you know a generation later + + align:start position:0% +surprised if you know a generation later + + + align:start position:0% +surprised if you know a generation later +they were being quoted in in you know in + + align:start position:0% +they were being quoted in in you know in + + + align:start position:0% +they were being quoted in in you know in +research being done by medieval writers + + align:start position:0% +research being done by medieval writers + + + align:start position:0% +research being done by medieval writers +inations of their model right I mean it + + align:start position:0% +inations of their model right I mean it + + + align:start position:0% +inations of their model right I mean it +seems like the way he characterizes + + align:start position:0% +seems like the way he characterizes + + + align:start position:0% +seems like the way he characterizes +these authors that that's exactly what + + align:start position:0% +these authors that that's exactly what + + + align:start position:0% +these authors that that's exactly what +they would do. They do get used in the + + align:start position:0% +they would do. They do get used in the + + + align:start position:0% +they would do. They do get used in the +building of the model even though they + + align:start position:0% +building of the model even though they + + + align:start position:0% +building of the model even though they +don't rely on the model. Absolutely. + + align:start position:0% +don't rely on the model. Absolutely. + + + align:start position:0% +don't rely on the model. Absolutely. +Absolutely. Let let's go on just a + + align:start position:0% +Absolutely. Let let's go on just a + + + align:start position:0% +Absolutely. Let let's go on just a +little bit further in that passage + + align:start position:0% +little bit further in that passage + + + align:start position:0% +little bit further in that passage +there. That is the medievals, right? + + align:start position:0% +there. That is the medievals, right? + + + align:start position:0% +there. That is the medievals, right? +Their cosmology and their religion were + + align:start position:0% +Their cosmology and their religion were + + + align:start position:0% +Their cosmology and their religion were +not such easy bedfellows as might be + + align:start position:0% +not such easy bedfellows as might be + + + align:start position:0% +not such easy bedfellows as might be +supposed, right? That's the that's the + + align:start position:0% +supposed, right? That's the that's the + + + align:start position:0% +supposed, right? That's the that's the +irony here. And we at first may fail to + + align:start position:0% +irony here. And we at first may fail to + + + align:start position:0% +irony here. And we at first may fail to +notice this. For the cosmology appears + + align:start position:0% +notice this. For the cosmology appears + + + align:start position:0% +notice this. For the cosmology appears +to us in its firmly theistic basis and + + align:start position:0% +to us in its firmly theistic basis and + + + align:start position:0% +to us in its firmly theistic basis and +its ready welcome to the supernatural to + + align:start position:0% +its ready welcome to the supernatural to + + + align:start position:0% +its ready welcome to the supernatural to +be eminently religious. That's what I + + align:start position:0% +be eminently religious. That's what I + + + align:start position:0% +be eminently religious. That's what I +was just trying to say and paraphrase. + + align:start position:0% +was just trying to say and paraphrase. + + + align:start position:0% +was just trying to say and paraphrase. +Um but then he says it is not eminently + + align:start position:0% +Um but then he says it is not eminently + + + align:start position:0% +Um but then he says it is not eminently +Christian. So he has this long text in + + align:start position:0% +Christian. So he has this long text in + + + align:start position:0% +Christian. So he has this long text in +which everything is pulled together, + + align:start position:0% +which everything is pulled together, + + + align:start position:0% +which everything is pulled together, +everything is syncric, right? Everything + + align:start position:0% +everything is syncric, right? Everything + + + align:start position:0% +everything is syncric, right? Everything +is eclectic. We we work and work and + + align:start position:0% +is eclectic. We we work and work and + + + align:start position:0% +is eclectic. We we work and work and +work to save the appearances. + + align:start position:0% +work to save the appearances. + + + align:start position:0% +work to save the appearances. +Um and yet on this one fundamental issue + + align:start position:0% +Um and yet on this one fundamental issue + + + align:start position:0% +Um and yet on this one fundamental issue +we have this unbridgegable divide right + + align:start position:0% +we have this unbridgegable divide right + + + align:start position:0% +we have this unbridgegable divide right +which + + align:start position:0% +which + + + align:start position:0% +which +is Christian that is theology spiritual + + align:start position:0% +is Christian that is theology spiritual + + + align:start position:0% +is Christian that is theology spiritual +advice homalytics whatever and then kind + + align:start position:0% +advice homalytics whatever and then kind + + + align:start position:0% +advice homalytics whatever and then kind +of the way we think the world really + + align:start position:0% +of the way we think the world really + + + align:start position:0% +of the way we think the world really +works and the way we write poetry and + + align:start position:0% +works and the way we write poetry and + + + align:start position:0% +works and the way we write poetry and +the way we make illusions and metaphors + + align:start position:0% +the way we make illusions and metaphors + + + align:start position:0% +the way we make illusions and metaphors +and the allegorories we tell and the + + align:start position:0% +and the allegorories we tell and the + + + align:start position:0% +and the allegorories we tell and the +fiction we write and the way we write + + align:start position:0% +fiction we write and the way we write + + + align:start position:0% +fiction we write and the way we write +love poetry. and and right and + + align:start position:0% +love poetry. and and right and + + + align:start position:0% +love poetry. and and right and +everything else that's important in + + align:start position:0% +everything else that's important in + + + align:start position:0% +everything else that's important in +life. + + align:start position:0% +life. + + + align:start position:0% +life. +Um, if this is true, if if Lewis isn't + + align:start position:0% +Um, if this is true, if if Lewis isn't + + + align:start position:0% +Um, if this is true, if if Lewis isn't +just setting this up to help himself get + + align:start position:0% +just setting this up to help himself get + + + align:start position:0% +just setting this up to help himself get +out of a sticky wicket, right, which he + + align:start position:0% +out of a sticky wicket, right, which he + + + align:start position:0% +out of a sticky wicket, right, which he +might + + align:start position:0% +might + + + align:start position:0% +might +be, one way we can reconcile these + + align:start position:0% +be, one way we can reconcile these + + + align:start position:0% +be, one way we can reconcile these +medievalists, if you will, the medieval + + align:start position:0% +medievalists, if you will, the medieval + + + align:start position:0% +medievalists, if you will, the medieval +world that we feel so comfortable + + align:start position:0% +world that we feel so comfortable + + + align:start position:0% +world that we feel so comfortable +imagining and say + + align:start position:0% +imagining and say + + + align:start position:0% +imagining and say +Binham's medieval world, which is so + + align:start position:0% +Binham's medieval world, which is so + + + align:start position:0% +Binham's medieval world, which is so +bizarre to us, is we could + + align:start position:0% +bizarre to us, is we could + + + align:start position:0% +bizarre to us, is we could +say, + + align:start position:0% +say, + + + align:start position:0% +say, +well, you know, + + align:start position:0% +well, you know, + + + align:start position:0% +well, you know, +Middle Earth is comfortable because + + align:start position:0% +Middle Earth is comfortable because + + + align:start position:0% +Middle Earth is comfortable because +Middle Earth is clearly part of this + + align:start position:0% + + + + align:start position:0% + +model and Binham's saints are so + + align:start position:0% +model and Binham's saints are so + + + align:start position:0% +model and Binham's saints are so +uncomfortable to us because they're part + + align:start position:0% +uncomfortable to us because they're part + + + align:start position:0% +uncomfortable to us because they're part +of that thing that is eminently + + align:start position:0% +of that thing that is eminently + + + align:start position:0% +of that thing that is eminently +Christian, right? They're the real deal. + + align:start position:0% +Christian, right? They're the real deal. + + + align:start position:0% +Christian, right? They're the real deal. +Also, I mean, I haven't read the books + + align:start position:0% +Also, I mean, I haven't read the books + + + align:start position:0% +Also, I mean, I haven't read the books +for a very long time. the but I don't + + align:start position:0% +for a very long time. the but I don't + + + align:start position:0% +for a very long time. the but I don't +remember that much religious stuff in + + align:start position:0% +remember that much religious stuff in + + + align:start position:0% +remember that much religious stuff in +the general like prominent like you know + + align:start position:0% +the general like prominent like you know + + + align:start position:0% +the general like prominent like you know +a lot of books nowadays when a lot I + + align:start position:0% +a lot of books nowadays when a lot I + + + align:start position:0% +a lot of books nowadays when a lot I +mean a lot of books nowadays when they + + align:start position:0% +mean a lot of books nowadays when they + + + align:start position:0% +mean a lot of books nowadays when they +write a fantasy thing they set up the + + align:start position:0% +write a fantasy thing they set up the + + + align:start position:0% +write a fantasy thing they set up the +whole world with you know here is one + + align:start position:0% +whole world with you know here is one + + + align:start position:0% +whole world with you know here is one +land here's another land here's another + + align:start position:0% +land here's another land here's another + + + align:start position:0% +land here's another land here's another +land here is the governments of these + + align:start position:0% +land here is the governments of these + + + align:start position:0% +land here is the governments of these +places which both he did and here's the + + align:start position:0% +places which both he did and here's the + + + align:start position:0% +places which both he did and here's the +basic religion of the group that was + + align:start position:0% +basic religion of the group that was + + + align:start position:0% +basic religion of the group that was +that the film really was was entirely + + align:start position:0% +that the film really was was entirely + + + align:start position:0% +that the film really was was entirely +you know it starts from creation + + align:start position:0% +you know it starts from creation + + + align:start position:0% +you know it starts from creation +basically by god and who creates these + + align:start position:0% +basically by god and who creates these + + + align:start position:0% +basically by god and who creates these +things who sing and create the world and + + align:start position:0% +things who sing and create the world and + + + align:start position:0% +things who sing and create the world and +which is you know an eminently you know + + align:start position:0% +which is you know an eminently you know + + + align:start position:0% +which is you know an eminently you know +where that comes from the singing as + + align:start position:0% +where that comes from the singing as + + + align:start position:0% +where that comes from the singing as +part of music of anor it sounds like + + align:start position:0% +part of music of anor it sounds like + + + align:start position:0% +part of music of anor it sounds like +something that was mentioned in here + + align:start position:0% +something that was mentioned in here + + + align:start position:0% +something that was mentioned in here +yeah it's also in in in in Botheus the + + align:start position:0% +yeah it's also in in in in Botheus the + + + align:start position:0% +yeah it's also in in in in Botheus the +his consolation of philosophy + + align:start position:0% +his consolation of philosophy + + + align:start position:0% +his consolation of philosophy +um + + align:start position:0% +um + + + align:start position:0% +um +basically all all philosophy comes to us + + align:start position:0% +basically all all philosophy comes to us + + + align:start position:0% +basically all all philosophy comes to us +through the I guess I don't I don't + + align:start position:0% +through the I guess I don't I don't + + + align:start position:0% +through the I guess I don't I don't +quite want to say angelic but the you + + align:start position:0% +quite want to say angelic but the you + + + align:start position:0% +quite want to say angelic but the you +know the celestial voices in in song. + + align:start position:0% +know the celestial voices in in song. + + + align:start position:0% +know the celestial voices in in song. +It's an interesting idea. + + align:start position:0% +It's an interesting idea. + + + align:start position:0% +It's an interesting idea. +Um and and and I think it's not an + + align:start position:0% +Um and and and I think it's not an + + + align:start position:0% +Um and and and I think it's not an +accident that Tolken is so fond + + align:start position:0% +accident that Tolken is so fond + + + align:start position:0% +accident that Tolken is so fond +of the of lyric + + align:start position:0% +of the of lyric + + + align:start position:0% +of the of lyric +poetry, right? I mean, the book doesn't + + align:start position:0% +poetry, right? I mean, the book doesn't + + + align:start position:0% +poetry, right? I mean, the book doesn't +actually sing, but it practically does, + + align:start position:0% +actually sing, but it practically does, + + + align:start position:0% +actually sing, but it practically does, +right? If you read it out loud, it would + + align:start position:0% +right? If you read it out loud, it would + + + align:start position:0% +right? If you read it out loud, it would +be good if you knew what meter to put + + align:start position:0% +be good if you knew what meter to put + + + align:start position:0% +be good if you knew what meter to put +with all of those poems, wouldn't it? + + align:start position:0% +with all of those poems, wouldn't it? + + + align:start position:0% +with all of those poems, wouldn't it? +when you read it out loud, you're never + + align:start position:0% +when you read it out loud, you're never + + + align:start position:0% +when you read it out loud, you're never +quite sure what to do with those because + + align:start position:0% +quite sure what to do with those because + + + align:start position:0% +quite sure what to do with those because +you have this feeling that you should + + align:start position:0% +you have this feeling that you should + + + align:start position:0% +you have this feeling that you should +have heard them before you just read + + align:start position:0% +have heard them before you just read + + + align:start position:0% +have heard them before you just read +them. And the I mean the thing that the + + align:start position:0% +them. And the I mean the thing that the + + + align:start position:0% +them. And the I mean the thing that the +Sylmerelion is the Kent Sylmerelion and + + align:start position:0% +Sylmerelion is the Kent Sylmerelion and + + + align:start position:0% +Sylmerelion is the Kent Sylmerelion and +it's supposed to be a whole long poem + + align:start position:0% +it's supposed to be a whole long poem + + + align:start position:0% +it's supposed to be a whole long poem +and he's paraphrasing it right in + + align:start position:0% +and he's paraphrasing it right in + + + align:start position:0% +and he's paraphrasing it right in +summary for us and that you know + + align:start position:0% +summary for us and that you know + + + align:start position:0% +summary for us and that you know +sometimes he has excerpts of the real + + align:start position:0% +sometimes he has excerpts of the real + + + align:start position:0% +sometimes he has excerpts of the real +thing and he'll have you know and even + + align:start position:0% +thing and he'll have you know and even + + + align:start position:0% +thing and he'll have you know and even +everything else you know all the other + + align:start position:0% +everything else you know all the other + + + align:start position:0% +everything else you know all the other +little stories he tells he's like well + + align:start position:0% +little stories he tells he's like well + + + align:start position:0% +little stories he tells he's like well +I'm just paraphrasing the the songs and + + align:start position:0% +I'm just paraphrasing the the songs and + + + align:start position:0% +I'm just paraphrasing the the songs and +the the ballads and Right. Right. Well, + + align:start position:0% +the the ballads and Right. Right. Well, + + + align:start position:0% +the the ballads and Right. Right. Well, +I mean the the the line of confusion for + + align:start position:0% +I mean the the the line of confusion for + + + align:start position:0% +I mean the the the line of confusion for +him + + align:start position:0% +him + + + align:start position:0% +him +between storytelling that is writing + + align:start position:0% +between storytelling that is writing + + + align:start position:0% +between storytelling that is writing +fiction and chronicle writing that is + + align:start position:0% +fiction and chronicle writing that is + + + align:start position:0% +fiction and chronicle writing that is +being a historian + + align:start position:0% +being a historian + + + align:start position:0% +being a historian +um is very is very fine. And and one of + + align:start position:0% +um is very is very fine. And and one of + + + align:start position:0% +um is very is very fine. And and one of +the ways you know that is because at the + + align:start position:0% +the ways you know that is because at the + + + align:start position:0% +the ways you know that is because at the +end of at the end of the return of the + + align:start position:0% +end of at the end of the return of the + + + align:start position:0% +end of at the end of the return of the +king you get all those + + align:start position:0% +king you get all those + + + align:start position:0% +king you get all those +appendices right I mean how many works + + align:start position:0% +appendices right I mean how many works + + + align:start position:0% +appendices right I mean how many works +of fiction come with what six seven + + align:start position:0% +of fiction come with what six seven + + + align:start position:0% +of fiction come with what six seven +appendices and and some of the + + align:start position:0% +appendices and and some of the + + + align:start position:0% +appendices and and some of the +appendices are about language okay fine + + align:start position:0% +appendices are about language okay fine + + + align:start position:0% +appendices are about language okay fine +you know we don't all speak Elvish so we + + align:start position:0% +you know we don't all speak Elvish so we + + + align:start position:0% +you know we don't all speak Elvish so we +have to have that clarified for us but + + align:start position:0% +have to have that clarified for us but + + + align:start position:0% +have to have that clarified for us but +some of the appendices are exactly the + + align:start position:0% +some of the appendices are exactly the + + + align:start position:0% +some of the appendices are exactly the +kind kind of appendices a historian + + align:start position:0% +kind kind of appendices a historian + + + align:start position:0% +kind kind of appendices a historian +would write. Now, it turns out you + + align:start position:0% +would write. Now, it turns out you + + + align:start position:0% +would write. Now, it turns out you +actually need to know this prequel. You + + align:start position:0% +actually need to know this prequel. You + + + align:start position:0% +actually need to know this prequel. You +need to know this tale. You need to know + + align:start position:0% +need to know this tale. You need to know + + + align:start position:0% +need to know this tale. You need to know +how this happened. You need to know + + align:start position:0% +how this happened. You need to know + + + align:start position:0% +how this happened. You need to know +where these people came from, right? + + align:start position:0% +where these people came from, right? + + + align:start position:0% +where these people came from, right? +It's completely like a historical + + align:start position:0% +It's completely like a historical + + + align:start position:0% +It's completely like a historical +text, you know, right down to the + + align:start position:0% +text, you know, right down to the + + + align:start position:0% +text, you know, right down to the +footnotes and the appendices. + + align:start position:0% +footnotes and the appendices. + + + align:start position:0% +footnotes and the appendices. +Um, why, you know, if you're really + + align:start position:0% +Um, why, you know, if you're really + + + align:start position:0% +Um, why, you know, if you're really +writing + + align:start position:0% +writing + + + align:start position:0% +writing +fiction, why not just get that into the + + align:start position:0% +fiction, why not just get that into the + + + align:start position:0% +fiction, why not just get that into the +story? After all, you + + align:start position:0% +story? After all, you + + + align:start position:0% +story? After all, you +could, but it makes it makes it more + + align:start position:0% +could, but it makes it makes it more + + + align:start position:0% +could, but it makes it makes it more +more readable. Just like a historian + + align:start position:0% +more readable. Just like a historian + + + align:start position:0% +more readable. Just like a historian +who's, you know, trying to write + + align:start position:0% +who's, you know, trying to write + + + align:start position:0% +who's, you know, trying to write +something and make it make his his + + align:start position:0% +something and make it make his his + + + align:start position:0% +something and make it make his his +treatis readable rather than dry, you + + align:start position:0% +treatis readable rather than dry, you + + + align:start position:0% +treatis readable rather than dry, you +know, push push a lot of the stuff into + + align:start position:0% +know, push push a lot of the stuff into + + + align:start position:0% +know, push push a lot of the stuff into +the appendix. Okay. Well, maybe the + + align:start position:0% +the appendix. Okay. Well, maybe the + + + align:start position:0% +the appendix. Okay. Well, maybe the +grammar, right? The Elvish grammar is + + align:start position:0% +grammar, right? The Elvish grammar is + + + align:start position:0% +grammar, right? The Elvish grammar is +dry, but some of the story material + + align:start position:0% +dry, but some of the story material + + + align:start position:0% +dry, but some of the story material +there is good. Some of the story + + align:start position:0% +there is good. Some of the story + + + align:start position:0% +there is good. Some of the story +material there ended up in the movies + + align:start position:0% +material there ended up in the movies + + + align:start position:0% +material there ended up in the movies +after all, + + align:start position:0% +after all, + + + align:start position:0% +after all, +right? Get those chips going. Yeah. Go + + align:start position:0% +right? Get those chips going. Yeah. Go + + + align:start position:0% +right? Get those chips going. Yeah. Go +ahead, Amory. Well, I think that's + + align:start position:0% +ahead, Amory. Well, I think that's + + + align:start position:0% +ahead, Amory. Well, I think that's +exactly the point. Is he writing a story + + align:start position:0% +exactly the point. Is he writing a story + + + align:start position:0% +exactly the point. Is he writing a story +or is he writing history? And I think I + + align:start position:0% +or is he writing history? And I think I + + + align:start position:0% +or is he writing history? And I think I +mean essentially he's writing the + + align:start position:0% +mean essentially he's writing the + + + align:start position:0% +mean essentially he's writing the +history of of this tale, right, as it + + align:start position:0% +history of of this tale, right, as it + + + align:start position:0% +history of of this tale, right, as it +occurred to him in his mind. So I think + + align:start position:0% +occurred to him in his mind. So I think + + + align:start position:0% +occurred to him in his mind. So I think +it I think it's really hard to make this + + align:start position:0% +it I think it's really hard to make this + + + align:start position:0% +it I think it's really hard to make this +distinction. Obviously it's not real, + + align:start position:0% +distinction. Obviously it's not real, + + + align:start position:0% +distinction. Obviously it's not real, +right? So it's not medieval history that + + align:start position:0% +right? So it's not medieval history that + + + align:start position:0% +right? So it's not medieval history that +he's writing, + + align:start position:0% +he's writing, + + + align:start position:0% +he's writing, +but I think it's more it's more + + align:start position:0% +but I think it's more it's more + + + align:start position:0% +but I think it's more it's more +scholarly than just a work of fiction, + + align:start position:0% +scholarly than just a work of fiction, + + + align:start position:0% +scholarly than just a work of fiction, +you know? I don't know if you can and + + align:start position:0% +you know? I don't know if you can and + + + align:start position:0% +you know? I don't know if you can and +from that point of view, I think it + + align:start position:0% +from that point of view, I think it + + + align:start position:0% +from that point of view, I think it +makes sense to be writing it in this + + align:start position:0% +makes sense to be writing it in this + + + align:start position:0% +makes sense to be writing it in this +kind of + + align:start position:0% +kind of + + + align:start position:0% +kind of +quasi scholarly manner. I had a + + align:start position:0% +quasi scholarly manner. I had a + + + align:start position:0% +quasi scholarly manner. I had a +question. Did he publish The Hobbit + + align:start position:0% +question. Did he publish The Hobbit + + + align:start position:0% +question. Did he publish The Hobbit +before he wrote the Lord? + + align:start position:0% +before he wrote the Lord? + + + align:start position:0% +before he wrote the Lord? +Yeah. Long before um much to the + + align:start position:0% +Yeah. Long before um much to the + + + align:start position:0% +Yeah. Long before um much to the +ridicule of his colleagues as you can + + align:start position:0% +ridicule of his colleagues as you can + + + align:start position:0% +ridicule of his colleagues as you can +imagine. Well, I don't know maybe you + + align:start position:0% +imagine. Well, I don't know maybe you + + + align:start position:0% +imagine. Well, I don't know maybe you +can't imagine. I mean sort of you know + + align:start position:0% +can't imagine. I mean sort of you know + + + align:start position:0% +can't imagine. I mean sort of you know +take your average faculty member at MIT + + align:start position:0% +take your average faculty member at MIT + + + align:start position:0% +take your average faculty member at MIT +and then add another sort of you know 50 + + align:start position:0% +and then add another sort of you know 50 + + + align:start position:0% +and then add another sort of you know 50 +times factor of + + align:start position:0% +times factor of + + + align:start position:0% +times factor of +stuffiness right and and then you've got + + align:start position:0% +stuffiness right and and then you've got + + + align:start position:0% +stuffiness right and and then you've got +you know your Oxford Dawn in the 20s30s + + align:start position:0% +you know your Oxford Dawn in the 20s30s + + + align:start position:0% +you know your Oxford Dawn in the 20s30s +or 40s. Um, I mean, his colleagues + + align:start position:0% +or 40s. Um, I mean, his colleagues + + + align:start position:0% +or 40s. Um, I mean, his colleagues +weren't just kind of beused. They were + + align:start position:0% +weren't just kind of beused. They were + + + align:start position:0% +weren't just kind of beused. They were +they were outraged. I mean, it was + + align:start position:0% +they were outraged. I mean, it was + + + align:start position:0% +they were outraged. I mean, it was +deeply embarrassing. It was like having + + align:start position:0% +deeply embarrassing. It was like having + + + align:start position:0% +deeply embarrassing. It was like having +a nutcase um on your + + align:start position:0% +a nutcase um on your + + + align:start position:0% +a nutcase um on your +faculty because I mean, and after all, + + align:start position:0% +faculty because I mean, and after all, + + + align:start position:0% +faculty because I mean, and after all, +The Hobbit is a very has a very + + align:start position:0% +The Hobbit is a very has a very + + + align:start position:0% +The Hobbit is a very has a very +different cast to it, right, than The + + align:start position:0% +different cast to it, right, than The + + + align:start position:0% +different cast to it, right, than The +Lord of the Rings, even though even + + align:start position:0% +Lord of the Rings, even though even + + + align:start position:0% +Lord of the Rings, even though even +though in some sense it's all one story, + + align:start position:0% +though in some sense it's all one story, + + + align:start position:0% +though in some sense it's all one story, +right? And often children who are old + + align:start position:0% +right? And often children who are old + + + align:start position:0% +right? And often children who are old +enough to read The Hobbit will discover + + align:start position:0% +enough to read The Hobbit will discover + + + align:start position:0% +enough to read The Hobbit will discover +much to their disappointment that + + align:start position:0% +much to their disappointment that + + + align:start position:0% +much to their disappointment that +they're not the least bit interested in + + align:start position:0% +they're not the least bit interested in + + + align:start position:0% +they're not the least bit interested in +The Lord of the Rings because you've got + + align:start position:0% +The Lord of the Rings because you've got + + + align:start position:0% +The Lord of the Rings because you've got +to get through that first what 60 pages + + align:start position:0% +to get through that first what 60 pages + + + align:start position:0% +to get through that first what 60 pages +before anything happens at all. Right. + + align:start position:0% +before anything happens at all. Right. + + + align:start position:0% +before anything happens at all. Right. +And that's not how you write a book for + + align:start position:0% +And that's not how you write a book for + + + align:start position:0% +And that's not how you write a book for +children. For sure. Yeah. Annie. No. + + align:start position:0% +children. For sure. Yeah. Annie. No. + + + align:start position:0% +children. For sure. Yeah. Annie. No. +Okay. I never got I started reading Lord + + align:start position:0% +Okay. I never got I started reading Lord + + + align:start position:0% +Okay. I never got I started reading Lord +of the Rings and I never got through it. + + align:start position:0% +of the Rings and I never got through it. + + + align:start position:0% +of the Rings and I never got through it. +I loved The Hobbit but couldn't deal + + align:start position:0% +I loved The Hobbit but couldn't deal + + + align:start position:0% +I loved The Hobbit but couldn't deal +with I just couldn't deal with the style + + align:start position:0% +with I just couldn't deal with the style + + + align:start position:0% +with I just couldn't deal with the style +of writing. Is that still true? Yeah. + + align:start position:0% +of writing. Is that still true? Yeah. + + + align:start position:0% +of writing. Is that still true? Yeah. +still. Uhhuh. It's what I love about + + align:start position:0% +still. Uhhuh. It's what I love about + + + align:start position:0% +still. Uhhuh. It's what I love about +also CS Lewis is just the way he writes. + + align:start position:0% +also CS Lewis is just the way he writes. + + + align:start position:0% +also CS Lewis is just the way he writes. +It just seems very marriageable. It's it + + align:start position:0% +It just seems very marriageable. It's it + + + align:start position:0% +It just seems very marriageable. It's it +seems very flowing while while J.R. + + align:start position:0% +seems very flowing while while J.R. + + + align:start position:0% +seems very flowing while while J.R. +Token sort of write like it to me it's + + align:start position:0% +Token sort of write like it to me it's + + + align:start position:0% +Token sort of write like it to me it's +even more like a history stuff because + + align:start position:0% +even more like a history stuff because + + + align:start position:0% +even more like a history stuff because +and in fact what he said in + + align:start position:0% +and in fact what he said in + + + align:start position:0% +and in fact what he said in +um how he wrote it, you know, pretending + + align:start position:0% +um how he wrote it, you know, pretending + + + align:start position:0% +um how he wrote it, you know, pretending +that this was something he was + + align:start position:0% +that this was something he was + + + align:start position:0% +that this was something he was +translating. I can see that a lot + + align:start position:0% +translating. I can see that a lot + + + align:start position:0% +translating. I can see that a lot +because therefore it sounds to me like + + align:start position:0% +because therefore it sounds to me like + + + align:start position:0% +because therefore it sounds to me like +he's trying to write a textbook almost. + + align:start position:0% +he's trying to write a textbook almost. + + + align:start position:0% +he's trying to write a textbook almost. +So it's very drag and very textbook like + + align:start position:0% +So it's very drag and very textbook like + + + align:start position:0% +So it's very drag and very textbook like +and more like writing a history than + + align:start position:0% +and more like writing a history than + + + align:start position:0% +and more like writing a history than +writing a story. Yeah. Go ahead, Ian. + + align:start position:0% +writing a story. Yeah. Go ahead, Ian. + + + align:start position:0% +writing a story. Yeah. Go ahead, Ian. +And I found I think just just as CS + + align:start position:0% +And I found I think just just as CS + + + align:start position:0% +And I found I think just just as CS +Lewis is saying and and kind of actually + + align:start position:0% +Lewis is saying and and kind of actually + + + align:start position:0% +Lewis is saying and and kind of actually +what I found about the discarded image + + align:start position:0% +what I found about the discarded image + + + align:start position:0% +what I found about the discarded image +as well is that he's it's interesting + + align:start position:0% +as well is that he's it's interesting + + + align:start position:0% +as well is that he's it's interesting +for its own merit and if it isn't then + + align:start position:0% +for its own merit and if it isn't then + + + align:start position:0% +for its own merit and if it isn't then +you're probably in trouble. And I mean I + + align:start position:0% +you're probably in trouble. And I mean I + + + align:start position:0% +you're probably in trouble. And I mean I +personally found it very interesting + + align:start position:0% +personally found it very interesting + + + align:start position:0% +personally found it very interesting +because of what it's talking about. The + + align:start position:0% +because of what it's talking about. The + + + align:start position:0% +because of what it's talking about. The +Lord of the Rings. The Lord of the + + align:start position:0% +Lord of the Rings. The Lord of the + + + align:start position:0% +Lord of the Rings. The Lord of the +Rings. just make sure as well as also a + + align:start position:0% +Rings. just make sure as well as also a + + + align:start position:0% +Rings. just make sure as well as also a +lot of discarded image I felt the same + + align:start position:0% +lot of discarded image I felt the same + + + align:start position:0% +lot of discarded image I felt the same +way he wrote in the like the very he + + align:start position:0% +way he wrote in the like the very he + + + align:start position:0% +way he wrote in the like the very he +didn't really you know he spent a lot of + + align:start position:0% +didn't really you know he spent a lot of + + + align:start position:0% +didn't really you know he spent a lot of +time talking about the examples and not + + align:start position:0% +time talking about the examples and not + + + align:start position:0% +time talking about the examples and not +you know and and there was analysis but + + align:start position:0% +you know and and there was analysis but + + + align:start position:0% +you know and and there was analysis but +it wasn't you know it was all it was all + + align:start position:0% +it wasn't you know it was all it was all + + + align:start position:0% +it wasn't you know it was all it was all +very entwined in the examples and if you + + align:start position:0% +very entwined in the examples and if you + + + align:start position:0% +very entwined in the examples and if you +if you didn't find and I was talking to + + align:start position:0% +if you didn't find and I was talking to + + + align:start position:0% +if you didn't find and I was talking to +Greg about this who didn't necessarily + + align:start position:0% +Greg about this who didn't necessarily + + + align:start position:0% +Greg about this who didn't necessarily +find some of the examples as compelling + + align:start position:0% +find some of the examples as compelling + + + align:start position:0% +find some of the examples as compelling +or as interesting as I did just because + + align:start position:0% +or as interesting as I did just because + + + align:start position:0% +or as interesting as I did just because +I'm interested in this kind of stuff and + + align:start position:0% +I'm interested in this kind of stuff and + + + align:start position:0% +I'm interested in this kind of stuff and +just you know it wasn't as interesting + + align:start position:0% +just you know it wasn't as interesting + + + align:start position:0% +just you know it wasn't as interesting +just like he's saying the medieval + + align:start position:0% +just like he's saying the medieval + + + align:start position:0% +just like he's saying the medieval +authors how they + + align:start position:0% +authors how they + + + align:start position:0% +authors how they +wrote I mean one one thing just to make + + align:start position:0% +wrote I mean one one thing just to make + + + align:start position:0% +wrote I mean one one thing just to make +a note of there's nothing per se that we + + align:start position:0% +a note of there's nothing per se that we + + + align:start position:0% +a note of there's nothing per se that we +can do about it but we don't + + align:start position:0% +can do about it but we don't + + + align:start position:0% +can do about it but we don't +share the vast wealth of sort of + + align:start position:0% +share the vast wealth of sort of + + + align:start position:0% +share the vast wealth of sort of +immediately recallable references that + + align:start position:0% +immediately recallable references that + + + align:start position:0% +immediately recallable references that +these guys are carrying around in their + + align:start position:0% +these guys are carrying around in their + + + align:start position:0% +these guys are carrying around in their +heads. I mean, these two individuals and + + align:start position:0% +heads. I mean, these two individuals and + + + align:start position:0% +heads. I mean, these two individuals and +and others of their of their time in + + align:start position:0% +and others of their of their time in + + + align:start position:0% +and others of their of their time in +particular, but but these two especially + + align:start position:0% +particular, but but these two especially + + + align:start position:0% +particular, but but these two especially +are living in some other + + align:start position:0% +are living in some other + + + align:start position:0% +are living in some other +place, right? I mean, they they just + + align:start position:0% +place, right? I mean, they they just + + + align:start position:0% +place, right? I mean, they they just +don't inhabit their everyday world all + + align:start position:0% +don't inhabit their everyday world all + + + align:start position:0% +don't inhabit their everyday world all +that much. + + align:start position:0% +that much. + + + align:start position:0% +that much. +uh for for Lewis it's clear that you + + align:start position:0% +uh for for Lewis it's clear that you + + + align:start position:0% +uh for for Lewis it's clear that you +know Dante is much more real than you + + align:start position:0% +know Dante is much more real than you + + + align:start position:0% +know Dante is much more real than you +know than the current government in + + align:start position:0% +know than the current government in + + + align:start position:0% +know than the current government in +Britain right at the time you know that + + align:start position:0% +Britain right at the time you know that + + + align:start position:0% +Britain right at the time you know that +that that's that's the set of references + + align:start position:0% +that that's that's the set of references + + + align:start position:0% +that that's that's the set of references +that inform his entire + + align:start position:0% +that inform his entire + + + align:start position:0% +that inform his entire +life and there and there are a set of + + align:start position:0% +life and there and there are a set of + + + align:start position:0% +life and there and there are a set of +references that for the most part we + + align:start position:0% +references that for the most part we + + + align:start position:0% +references that for the most part we +don't have anymore are um or if we do, + + align:start position:0% +don't have anymore are um or if we do, + + + align:start position:0% +don't have anymore are um or if we do, +we've just picked them up on the edges, + + align:start position:0% +we've just picked them up on the edges, + + + align:start position:0% +we've just picked them up on the edges, +right? We've read part of the Canterbury + + align:start position:0% +right? We've read part of the Canterbury + + + align:start position:0% +right? We've read part of the Canterbury +Tales, you know, in translation, right? + + align:start position:0% +Tales, you know, in translation, right? + + + align:start position:0% +Tales, you know, in translation, right? +We've read Dante, but in translation, + + align:start position:0% +We've read Dante, but in translation, + + + align:start position:0% +We've read Dante, but in translation, +we've read Beaowolf again, um in + + align:start position:0% +we've read Beaowolf again, um in + + + align:start position:0% +we've read Beaowolf again, um in +translation. And and maybe we haven't + + align:start position:0% +translation. And and maybe we haven't + + + align:start position:0% +translation. And and maybe we haven't +even read all of those. We've just read + + align:start position:0% +even read all of those. We've just read + + + align:start position:0% +even read all of those. We've just read +one, right? Or or a smattering of of + + align:start position:0% +one, right? Or or a smattering of of + + + align:start position:0% +one, right? Or or a smattering of of +one. And it's h it's hard to um to even + + align:start position:0% +one. And it's h it's hard to um to even + + + align:start position:0% +one. And it's h it's hard to um to even +put ourselves into their sort of + + align:start position:0% +put ourselves into their sort of + + + align:start position:0% +put ourselves into their sort of +creative mental space, right? Because + + align:start position:0% +creative mental space, right? Because + + + align:start position:0% +creative mental space, right? Because +the set of facts, the set of + + align:start position:0% +the set of facts, the set of + + + align:start position:0% +the set of facts, the set of +information, the set of ideas that we're + + align:start position:0% +information, the set of ideas that we're + + + align:start position:0% +information, the set of ideas that we're +carrying around are are not, you know, + + align:start position:0% +carrying around are are not, you know, + + + align:start position:0% +carrying around are are not, you know, +are not there set at all. But Annie, you + + align:start position:0% +are not there set at all. But Annie, you + + + align:start position:0% +are not there set at all. But Annie, you +were going to say something. Was it you? + + align:start position:0% +were going to say something. Was it you? + + + align:start position:0% +were going to say something. Was it you? +Was it Amarie? No. Okay. Let me change + + align:start position:0% +Was it Amarie? No. Okay. Let me change + + + align:start position:0% +Was it Amarie? No. Okay. Let me change +tax for a minute completely and I think + + align:start position:0% +tax for a minute completely and I think + + + align:start position:0% +tax for a minute completely and I think +we'll come we'll come back around to all + + align:start position:0% +we'll come we'll come back around to all + + + align:start position:0% +we'll come we'll come back around to all +of this. But let let me try another + + align:start position:0% +of this. But let let me try another + + + align:start position:0% +of this. But let let me try another +comparison with something we've already + + align:start position:0% +comparison with something we've already + + + align:start position:0% +comparison with something we've already +read. So + + align:start position:0% +read. So + + + align:start position:0% +read. So +Broadell, one of the things that we were + + align:start position:0% +Broadell, one of the things that we were + + + align:start position:0% +Broadell, one of the things that we were +thinking about with + + align:start position:0% +thinking about with + + + align:start position:0% +thinking about with +Broadell was the impact in his case of + + align:start position:0% +Broadell was the impact in his case of + + + align:start position:0% +Broadell was the impact in his case of +the German prisoner of war experience, + + align:start position:0% +the German prisoner of war experience, + + + align:start position:0% +the German prisoner of war experience, +right? + + align:start position:0% +right? + + + align:start position:0% +right? +And maybe not a rejection of all that + + align:start position:0% +And maybe not a rejection of all that + + + align:start position:0% +And maybe not a rejection of all that +was modern, but certainly a longing, + + align:start position:0% +was modern, but certainly a longing, + + + align:start position:0% +was modern, but certainly a longing, +right, for something that was not + + align:start position:0% +right, for something that was not + + + align:start position:0% +right, for something that was not +modern, in his case, early modern and a + + align:start position:0% +modern, in his case, early modern and a + + + align:start position:0% +modern, in his case, early modern and a +place, right, a strong strong attachment + + align:start position:0% +place, right, a strong strong attachment + + + align:start position:0% +place, right, a strong strong attachment +to place, which in his case was + + align:start position:0% +to place, which in his case was + + + align:start position:0% +to place, which in his case was +Mediterranean + + align:start position:0% +Mediterranean + + + align:start position:0% +Mediterranean +France, to the point where we even + + align:start position:0% +France, to the point where we even + + + align:start position:0% +France, to the point where we even +thought that we might want to classify + + align:start position:0% +thought that we might want to classify + + + align:start position:0% +thought that we might want to classify +by that book in one particular sense, + + align:start position:0% +by that book in one particular sense, + + + align:start position:0% +by that book in one particular sense, +right? As a love letter to that place + + align:start position:0% +right? As a love letter to that place + + + align:start position:0% +right? As a love letter to that place +and that + + align:start position:0% +and that + + + align:start position:0% +and that +time, would we want to make similar + + align:start position:0% +time, would we want to make similar + + + align:start position:0% +time, would we want to make similar +arguments with say Middle Earth or I + + align:start position:0% +arguments with say Middle Earth or I + + + align:start position:0% +arguments with say Middle Earth or I +should say the Lord of the Rings? + + align:start position:0% +should say the Lord of the Rings? + + + align:start position:0% +should say the Lord of the Rings? +Go ahead, Miranda. Especially from the + + align:start position:0% +Go ahead, Miranda. Especially from the + + + align:start position:0% +Go ahead, Miranda. Especially from the +article where they sounded a lot like + + align:start position:0% +article where they sounded a lot like + + + align:start position:0% +article where they sounded a lot like +him in sort of the well what they you + + align:start position:0% +him in sort of the well what they you + + + align:start position:0% +him in sort of the well what they you +know calling them sort of sort of + + align:start position:0% +know calling them sort of sort of + + + align:start position:0% +know calling them sort of sort of +dinosaurs for what they really wanted + + align:start position:0% +dinosaurs for what they really wanted + + + align:start position:0% +dinosaurs for what they really wanted +was to keep these old stories and old + + align:start position:0% +was to keep these old stories and old + + + align:start position:0% +was to keep these old stories and old +feelings and yet because they were + + align:start position:0% +feelings and yet because they were + + + align:start position:0% +feelings and yet because they were +trying to keep these thing alive. + + align:start position:0% +trying to keep these thing alive. + + + align:start position:0% +trying to keep these thing alive. +They're actually pioneers in a bunch of + + align:start position:0% +They're actually pioneers in a bunch of + + + align:start position:0% +They're actually pioneers in a bunch of +different ways like you know they're one + + align:start position:0% +different ways like you know they're one + + + align:start position:0% +different ways like you know they're one +like he says you know the first person + + align:start position:0% +like he says you know the first person + + + align:start position:0% +like he says you know the first person +to basically say well it's okay to talk + + align:start position:0% +to basically say well it's okay to talk + + + align:start position:0% +to basically say well it's okay to talk +about love as a historical thing and by + + align:start position:0% +about love as a historical thing and by + + + align:start position:0% +about love as a historical thing and by +for CS Lewis and some of the fantasy + + align:start position:0% +for CS Lewis and some of the fantasy + + + align:start position:0% +for CS Lewis and some of the fantasy +stuff it's okay to write you know write + + align:start position:0% +stuff it's okay to write you know write + + + align:start position:0% +stuff it's okay to write you know write +fantasies that for adult for adults and + + align:start position:0% +fantasies that for adult for adults and + + + align:start position:0% +fantasies that for adult for adults and +it's sort of I think the same thing + + align:start position:0% +it's sort of I think the same thing + + + align:start position:0% +it's sort of I think the same thing +happened with Rodella that you know + + align:start position:0% +happened with Rodella that you know + + + align:start position:0% +happened with Rodella that you know +because he sort of wanted to keep a hold + + align:start position:0% +because he sort of wanted to keep a hold + + + align:start position:0% +because he sort of wanted to keep a hold +of this old thing this oldfashioned + + align:start position:0% +of this old thing this oldfashioned + + + align:start position:0% +of this old thing this oldfashioned +feeling yet he was also this pioneer of + + align:start position:0% +feeling yet he was also this pioneer of + + + align:start position:0% +feeling yet he was also this pioneer of +what of the way to do such a thing, + + align:start position:0% +what of the way to do such a thing, + + + align:start position:0% +what of the way to do such a thing, +right? I mean, after all, um, the + + align:start position:0% +right? I mean, after all, um, the + + + align:start position:0% +right? I mean, after all, um, the +Mediterranean in the age of Philip II is + + align:start position:0% +Mediterranean in the age of Philip II is + + + align:start position:0% +Mediterranean in the age of Philip II is +clearly a history book, + + align:start position:0% +clearly a history book, + + + align:start position:0% +clearly a history book, +right? And The Lord of the Rings is + + align:start position:0% +right? And The Lord of the Rings is + + + align:start position:0% +right? And The Lord of the Rings is +clearly in the bookstore under + + align:start position:0% +clearly in the bookstore under + + + align:start position:0% +clearly in the bookstore under +fiction and there's no movie, right, for + + align:start position:0% +fiction and there's no movie, right, for + + + align:start position:0% +fiction and there's no movie, right, for +uh the Mediterranean in the age of + + align:start position:0% +uh the Mediterranean in the age of + + + align:start position:0% +uh the Mediterranean in the age of +Philip II. Can you imagine the movie? + + align:start position:0% +Philip II. Can you imagine the movie? + + + align:start position:0% +Philip II. Can you imagine the movie? +And it would most certainly not be + + align:start position:0% +And it would most certainly not be + + + align:start position:0% +And it would most certainly not be +filmed in New Zealand, right? Not a + + align:start position:0% +filmed in New Zealand, right? Not a + + + align:start position:0% +filmed in New Zealand, right? Not a +chance. Yeah. Go ahead, Peter. I mean, + + align:start position:0% +chance. Yeah. Go ahead, Peter. I mean, + + + align:start position:0% +chance. Yeah. Go ahead, Peter. I mean, +we made the comparison with Brell that + + align:start position:0% +we made the comparison with Brell that + + + align:start position:0% +we made the comparison with Brell that +he wasn't really living, you know, in + + align:start position:0% +he wasn't really living, you know, in + + + align:start position:0% +he wasn't really living, you know, in +his time frame. I mean, both Lewis and + + align:start position:0% +his time frame. I mean, both Lewis and + + + align:start position:0% +his time frame. I mean, both Lewis and +Tolken were World War I veterans, right? + + align:start position:0% +Tolken were World War I veterans, right? + + + align:start position:0% +Tolken were World War I veterans, right? +That's what I seem to remember. that I + + align:start position:0% +That's what I seem to remember. that I + + + align:start position:0% +That's what I seem to remember. that I +mean that's the only compar I mean I + + align:start position:0% +mean that's the only compar I mean I + + + align:start position:0% +mean that's the only compar I mean I +can't really speak from experience of + + align:start position:0% +can't really speak from experience of + + + align:start position:0% +can't really speak from experience of +reading the books by Louis and Tolken + + align:start position:0% +reading the books by Louis and Tolken + + + align:start position:0% +reading the books by Louis and Tolken +but it seems to me that the comparison + + align:start position:0% +but it seems to me that the comparison + + + align:start position:0% +but it seems to me that the comparison +between Bradell and Louis and Tolken + + align:start position:0% +between Bradell and Louis and Tolken + + + align:start position:0% +between Bradell and Louis and Tolken +would be that their experiences in war + + align:start position:0% +would be that their experiences in war + + + align:start position:0% +would be that their experiences in war +kind of make make them less willing to + + align:start position:0% +kind of make make them less willing to + + + align:start position:0% +kind of make make them less willing to +want to live in a contemporary their + + align:start position:0% +want to live in a contemporary their + + + align:start position:0% +want to live in a contemporary their +contemporary time period and they're + + align:start position:0% +contemporary time period and they're + + + align:start position:0% +contemporary time period and they're +much more comfortable living somewhere + + align:start position:0% +much more comfortable living somewhere + + + align:start position:0% +much more comfortable living somewhere +else where um you know they can control + + align:start position:0% +else where um you know they can control + + + align:start position:0% +else where um you know they can control +what's going on although I mean this + + align:start position:0% +what's going on although I mean this + + + align:start position:0% +what's going on although I mean this +isn't quite as much the case with + + align:start position:0% +isn't quite as much the case with + + + align:start position:0% +isn't quite as much the case with +Broadell but clearly with both Lewis and + + align:start position:0% +Broadell but clearly with both Lewis and + + + align:start position:0% +Broadell but clearly with both Lewis and +Tolken the mental world they're living + + align:start position:0% +Tolken the mental world they're living + + + align:start position:0% +Tolken the mental world they're living +in. It's full of + + align:start position:0% +in. It's full of + + + align:start position:0% +in. It's full of +war, right? I mean, it's, you know, + + align:start position:0% +war, right? I mean, it's, you know, + + + align:start position:0% +war, right? I mean, it's, you know, +presumably the horrors of the 20th + + align:start position:0% +presumably the horrors of the 20th + + + align:start position:0% +presumably the horrors of the 20th +century don't shock them given the given + + align:start position:0% +century don't shock them given the given + + + align:start position:0% +century don't shock them given the given +the me the the violence of the mental + + align:start position:0% +the me the the violence of the mental + + + align:start position:0% +the me the the violence of the mental +world um that that that they're + + align:start position:0% +world um that that that they're + + + align:start position:0% +world um that that that they're +inhabiting. Go ahead, Amarie. + + align:start position:0% +inhabiting. Go ahead, Amarie. + + + align:start position:0% +inhabiting. Go ahead, Amarie. +I think if you look at Lord of the Rings + + align:start position:0% +I think if you look at Lord of the Rings + + + align:start position:0% +I think if you look at Lord of the Rings +especially, you can see a lot of I think + + align:start position:0% +especially, you can see a lot of I think + + + align:start position:0% +especially, you can see a lot of I think +World War I influences in it. I think + + align:start position:0% +World War I influences in it. I think + + + align:start position:0% +World War I influences in it. I think +the book makes + + align:start position:0% +the book makes + + + align:start position:0% +the book makes +a the reference to it and I think I've + + align:start position:0% +a the reference to it and I think I've + + + align:start position:0% +a the reference to it and I think I've +heard other people talking about it as + + align:start position:0% +heard other people talking about it as + + + align:start position:0% +heard other people talking about it as +well. Like if you take the dead marshes + + align:start position:0% +well. Like if you take the dead marshes + + + align:start position:0% +well. Like if you take the dead marshes +with people lying on their backs looking + + align:start position:0% +with people lying on their backs looking + + + align:start position:0% +with people lying on their backs looking +up. I mean that's how you died when you + + align:start position:0% +up. I mean that's how you died when you + + + align:start position:0% +up. I mean that's how you died when you +were in a trench. And that's I think + + align:start position:0% +were in a trench. And that's I think + + + align:start position:0% +were in a trench. And that's I think +that's you can find other very similar + + align:start position:0% +that's you can find other very similar + + + align:start position:0% +that's you can find other very similar +analogies. So in a way yes I think we + + align:start position:0% +analogies. So in a way yes I think we + + + align:start position:0% +analogies. So in a way yes I think we +have them escaping to this world where + + align:start position:0% +have them escaping to this world where + + + align:start position:0% +have them escaping to this world where +they're in control but still that world + + align:start position:0% +they're in control but still that world + + + align:start position:0% +they're in control but still that world +is dominated by memories that they can't + + align:start position:0% +is dominated by memories that they can't + + + align:start position:0% +is dominated by memories that they can't +leave behind even though they're + + align:start position:0% +leave behind even though they're + + + align:start position:0% +leave behind even though they're +escaping. So, I think it's it's an + + align:start position:0% +escaping. So, I think it's it's an + + + align:start position:0% +escaping. So, I think it's it's an +interesting what were you saying, Lana? + + align:start position:0% +interesting what were you saying, Lana? + + + align:start position:0% +interesting what were you saying, Lana? +I was thinking it's an escape thing, but + + align:start position:0% +I was thinking it's an escape thing, but + + + align:start position:0% +I was thinking it's an escape thing, but +and they're creating this other world + + align:start position:0% +and they're creating this other world + + + align:start position:0% +and they're creating this other world +and it would still be very heavily + + align:start position:0% +and it would still be very heavily + + + align:start position:0% +and it would still be very heavily +influenced by their war experiences, but + + align:start position:0% +influenced by their war experiences, but + + + align:start position:0% +influenced by their war experiences, but +another way if since they keep on + + align:start position:0% +another way if since they keep on + + + align:start position:0% +another way if since they keep on +creating a past, + + align:start position:0% +creating a past, + + + align:start position:0% +creating a past, +World War I was really, really shocking + + align:start position:0% +World War I was really, really shocking + + + align:start position:0% +World War I was really, really shocking +in general. I mean, it was horrible. But + + align:start position:0% +in general. I mean, it was horrible. But + + + align:start position:0% +in general. I mean, it was horrible. But +imagine if instead of the world that + + align:start position:0% +imagine if instead of the world that + + + align:start position:0% +imagine if instead of the world that +instead of if if in the world that we + + align:start position:0% +instead of if if in the world that we + + + align:start position:0% +instead of if if in the world that we +had been living there had been all these + + align:start position:0% +had been living there had been all these + + + align:start position:0% +had been living there had been all these +big huge horrible wars before World War + + align:start position:0% +big huge horrible wars before World War + + + align:start position:0% +big huge horrible wars before World War +I wouldn't have been as bad. + + align:start position:0% +I wouldn't have been as bad. + + + align:start position:0% +I wouldn't have been as bad. +But there have been many horrible wars. + + align:start position:0% +But there have been many horrible wars. + + + align:start position:0% +But there have been many horrible wars. +There have been many horrible wars. Why? + + align:start position:0% +There have been many horrible wars. Why? + + + align:start position:0% +There have been many horrible wars. Why? +I mean an interesting question that that + + align:start position:0% +I mean an interesting question that that + + + align:start position:0% +I mean an interesting question that that +historians of the 20th century are you + + align:start position:0% +historians of the 20th century are you + + + align:start position:0% +historians of the 20th century are you +know sort of endlessly deeply fascinated + + align:start position:0% +know sort of endlessly deeply fascinated + + + align:start position:0% +know sort of endlessly deeply fascinated +by right is why why does World War I + + align:start position:0% +by right is why why does World War I + + + align:start position:0% +by right is why why does World War I +have this incredible cultural + + align:start position:0% +have this incredible cultural + + + align:start position:0% +have this incredible cultural +impact right why why is I mean + + align:start position:0% +impact right why why is I mean + + + align:start position:0% +impact right why why is I mean +that historical experience which you + + align:start position:0% +that historical experience which you + + + align:start position:0% +that historical experience which you +know after all if we knew a lot about um + + align:start position:0% +know after all if we knew a lot about um + + + align:start position:0% +know after all if we knew a lot about um +the 30 years war right if you grew up in + + align:start position:0% +the 30 years war right if you grew up in + + + align:start position:0% +the 30 years war right if you grew up in +as a school child in Germany + + align:start position:0% +as a school child in Germany + + + align:start position:0% +as a school child in Germany +you would have been steeped in the + + align:start position:0% +you would have been steeped in the + + + align:start position:0% +you would have been steeped in the +simplicimous literature. You know, + + align:start position:0% +simplicimous literature. You know, + + + align:start position:0% +simplicimous literature. You know, +that's a pretty miserable, awful book. + + align:start position:0% +that's a pretty miserable, awful book. + + + align:start position:0% +that's a pretty miserable, awful book. +Um, and to read it in German is triply + + align:start position:0% +Um, and to read it in German is triply + + + align:start position:0% +Um, and to read it in German is triply +miserable and awful. Uh, so I mean, + + align:start position:0% +miserable and awful. Uh, so I mean, + + + align:start position:0% +miserable and awful. Uh, so I mean, +Europeans had narratives for themselves + + align:start position:0% +Europeans had narratives for themselves + + + align:start position:0% +Europeans had narratives for themselves +of of other horrific moments that that, + + align:start position:0% +of of other horrific moments that that, + + + align:start position:0% +of of other horrific moments that that, +you know, that upset, if you will, the + + align:start position:0% +you know, that upset, if you will, the + + + align:start position:0% +you know, that upset, if you will, the +very foundations of culture. And yet, + + align:start position:0% +very foundations of culture. And yet, + + + align:start position:0% +very foundations of culture. And yet, +and yet World War I has played out, at + + align:start position:0% +and yet World War I has played out, at + + + align:start position:0% +and yet World War I has played out, at +least amongst the historians and the + + align:start position:0% +least amongst the historians and the + + + align:start position:0% +least amongst the historians and the +literary types, right, as this deeply + + align:start position:0% +literary types, right, as this deeply + + + align:start position:0% +literary types, right, as this deeply +um unsettling + + align:start position:0% +um unsettling + + + align:start position:0% +um unsettling +experience and and I think we're, you + + align:start position:0% +experience and and I think we're, you + + + align:start position:0% +experience and and I think we're, you +know, we're seeing it played out in + + align:start position:0% +know, we're seeing it played out in + + + align:start position:0% +know, we're seeing it played out in +these middle of the century historians. + + align:start position:0% +these middle of the century historians. + + + align:start position:0% +these middle of the century historians. +Yeah. Go ahead, Miranda. I mean, I'd + + align:start position:0% +Yeah. Go ahead, Miranda. I mean, I'd + + + align:start position:0% +Yeah. Go ahead, Miranda. I mean, I'd +always learned that one of the major + + align:start position:0% +always learned that one of the major + + + align:start position:0% +always learned that one of the major +reasons why it was so dramatic was + + align:start position:0% +reasons why it was so dramatic was + + + align:start position:0% +reasons why it was so dramatic was +because they were basically trying to + + align:start position:0% +because they were basically trying to + + + align:start position:0% +because they were basically trying to +keep with the oldfashioned warfare + + align:start position:0% +keep with the oldfashioned warfare + + + align:start position:0% +keep with the oldfashioned warfare +where, you know, you run at people from + + align:start position:0% +where, you know, you run at people from + + + align:start position:0% +where, you know, you run at people from +across the, you know, the land. And but + + align:start position:0% +across the, you know, the land. And but + + + align:start position:0% +across the, you know, the land. And but +this is a point when we were starting to + + align:start position:0% +this is a point when we were starting to + + + align:start position:0% +this is a point when we were starting to +get into machine guns and such like + + align:start position:0% +get into machine guns and such like + + + align:start position:0% +get into machine guns and such like +that. And so it was it was just this + + align:start position:0% +that. And so it was it was just this + + + align:start position:0% +that. And so it was it was just this +sort of absolute slaughter that was just + + align:start position:0% +sort of absolute slaughter that was just + + + align:start position:0% +sort of absolute slaughter that was just +pointless was the problem. Like before + + align:start position:0% +pointless was the problem. Like before + + + align:start position:0% +pointless was the problem. Like before +then, you know, war sort of it wasn't, + + align:start position:0% +then, you know, war sort of it wasn't, + + + align:start position:0% +then, you know, war sort of it wasn't, +you know, didn't have that much point, + + align:start position:0% +you know, didn't have that much point, + + + align:start position:0% +you know, didn't have that much point, +but just wasn't this. Yeah. + + align:start position:0% +but just wasn't this. Yeah. + + + align:start position:0% +but just wasn't this. Yeah. +And it wasn't this, you know, I've moved + + align:start position:0% +And it wasn't this, you know, I've moved + + + align:start position:0% +And it wasn't this, you know, I've moved +two inches and then I've died. You know, + + align:start position:0% +two inches and then I've died. You know, + + + align:start position:0% +two inches and then I've died. You know, +you move usually, you know, at least 3, + + align:start position:0% +you move usually, you know, at least 3, + + + align:start position:0% +you move usually, you know, at least 3, +four feet. + + align:start position:0% +four feet. + + + align:start position:0% +four feet. +So, was and it didn't just a subtle + + align:start position:0% +So, was and it didn't just a subtle + + + align:start position:0% +So, was and it didn't just a subtle +distinction and it just it like killed + + align:start position:0% +distinction and it just it like killed + + + align:start position:0% +distinction and it just it like killed +off basically like an entire generation + + align:start position:0% +off basically like an entire generation + + + align:start position:0% +off basically like an entire generation +of people versus, you know, other wars + + align:start position:0% +of people versus, you know, other wars + + + align:start position:0% +of people versus, you know, other wars +where they kill off a lot and lot of + + align:start position:0% +where they kill off a lot and lot of + + + align:start position:0% +where they kill off a lot and lot of +people, but it wasn't one specific, you + + align:start position:0% +people, but it wasn't one specific, you + + + align:start position:0% +people, but it wasn't one specific, you +know, upand cominging generation. That + + align:start position:0% +know, upand cominging generation. That + + + align:start position:0% +know, upand cominging generation. That +may be the key piece. But go but go + + align:start position:0% +may be the key piece. But go but go + + + align:start position:0% +may be the key piece. But go but go +ahead, Nick. Um I was thinking about two + + align:start position:0% +ahead, Nick. Um I was thinking about two + + + align:start position:0% +ahead, Nick. Um I was thinking about two +things in um in Tolken that like reflect + + align:start position:0% +things in um in Tolken that like reflect + + + align:start position:0% +things in um in Tolken that like reflect +on World War I. Like the first one + + align:start position:0% +on World War I. Like the first one + + + align:start position:0% +on World War I. Like the first one +that's was actually done in the movie + + align:start position:0% +that's was actually done in the movie + + + align:start position:0% +that's was actually done in the movie +and I don't remember it exactly from the + + align:start position:0% +and I don't remember it exactly from the + + + align:start position:0% +and I don't remember it exactly from the +book but it definitely hits on things is + + align:start position:0% +book but it definitely hits on things is + + + align:start position:0% +book but it definitely hits on things is +where like the Saron characters talking + + align:start position:0% +where like the Saron characters talking + + + align:start position:0% +where like the Saron characters talking +about how there's this new age and it's + + align:start position:0% +about how there's this new age and it's + + + align:start position:0% +about how there's this new age and it's +like the iron hand of the orc and you + + align:start position:0% +like the iron hand of the orc and you + + + align:start position:0% +like the iron hand of the orc and you +know machinery + + align:start position:0% +know machinery + + + align:start position:0% +know machinery +exactly like World War I. It's almost + + align:start position:0% +exactly like World War I. It's almost + + + align:start position:0% +exactly like World War I. It's almost +like I feel like he's contrasting like + + align:start position:0% +like I feel like he's contrasting like + + + align:start position:0% +like I feel like he's contrasting like +World War I being like the uh you know + + align:start position:0% +World War I being like the uh you know + + + align:start position:0% +World War I being like the uh you know +the darker armies versus the uh you know + + align:start position:0% +the darker armies versus the uh you know + + + align:start position:0% +the darker armies versus the uh you know +the guys on horses and stuff because + + align:start position:0% +the guys on horses and stuff because + + + align:start position:0% +the guys on horses and stuff because +like the thing you see with the guys and + + align:start position:0% +like the thing you see with the guys and + + + align:start position:0% +like the thing you see with the guys and +horses that there's heroes. There's like + + align:start position:0% +horses that there's heroes. There's like + + + align:start position:0% +horses that there's heroes. There's like +guys who you know individual achievement + + align:start position:0% +guys who you know individual achievement + + + align:start position:0% +guys who you know individual achievement +and that in World World War I is like + + align:start position:0% +and that in World World War I is like + + + align:start position:0% +and that in World World War I is like +the one war in history that like I know + + align:start position:0% +the one war in history that like I know + + + align:start position:0% +the one war in history that like I know +a bit about that I can't name a single + + align:start position:0% +a bit about that I can't name a single + + + align:start position:0% +a bit about that I can't name a single +hero from like I can't name a general. + + align:start position:0% +hero from like I can't name a general. + + + align:start position:0% +hero from like I can't name a general. +The red bars. + + align:start position:0% + + + + align:start position:0% + +I thought Snoopy was the hero. Come on. + + align:start position:0% +I thought Snoopy was the hero. Come on. + + + align:start position:0% +I thought Snoopy was the hero. Come on. +Doesn't Snoopy take him down? Yes. Yeah. + + align:start position:0% +Doesn't Snoopy take him down? Yes. Yeah. + + + align:start position:0% +Doesn't Snoopy take him down? Yes. Yeah. +Did you guys Do you guys was that song + + align:start position:0% +Did you guys Do you guys was that song + + + align:start position:0% +Did you guys Do you guys was that song +still? I don't know the song. Okay, + + align:start position:0% +still? I don't know the song. Okay, + + + align:start position:0% +still? I don't know the song. Okay, +we're not going to sing it though. Um + + align:start position:0% +we're not going to sing it though. Um + + + align:start position:0% +we're not going to sing it though. Um +later another class. + + align:start position:0% +later another class. + + + align:start position:0% +later another class. +Um, okay. So, let's think about heroes + + align:start position:0% +Um, okay. So, let's think about heroes + + + align:start position:0% +Um, okay. So, let's think about heroes +for a moment because I think that is a + + align:start position:0% +for a moment because I think that is a + + + align:start position:0% +for a moment because I think that is a +critical piece to this. Aside from the + + align:start position:0% +critical piece to this. Aside from the + + + align:start position:0% +critical piece to this. Aside from the +Red Baron, it may well have felt like + + align:start position:0% +Red Baron, it may well have felt like + + + align:start position:0% +Red Baron, it may well have felt like +there was nothing heroic about World War + + align:start position:0% +there was nothing heroic about World War + + + align:start position:0% +there was nothing heroic about World War +I. Ultimately, it was + + align:start position:0% +I. Ultimately, it was + + + align:start position:0% +I. Ultimately, it was +anti-heroic. Okay. Now, the heroic mode + + align:start position:0% +anti-heroic. Okay. Now, the heroic mode + + + align:start position:0% +anti-heroic. Okay. Now, the heroic mode +is one we recognize. Um that who I just + + align:start position:0% +is one we recognize. Um that who I just + + + align:start position:0% +is one we recognize. Um that who I just +happened to bring with me cuz I thought + + align:start position:0% +happened to bring with me cuz I thought + + + align:start position:0% +happened to bring with me cuz I thought +it might come in handy. + + align:start position:0% +it might come in handy. + + + align:start position:0% +it might come in handy. +Um if I can find love coincidentally. + + align:start position:0% +Um if I can find love coincidentally. + + + align:start position:0% +Um if I can find love coincidentally. +Yeah, + + align:start position:0% +Yeah, + + + align:start position:0% +Yeah, +coincidentally. + + align:start position:0% +coincidentally. + + + align:start position:0% +coincidentally. +Okay. + + align:start position:0% + + + + align:start position:0% + +Um this is Beaolf with the dragon. + + align:start position:0% +Um this is Beaolf with the dragon. + + + align:start position:0% +Um this is Beaolf with the dragon. +That's the other thing, right? It's one + + align:start position:0% +That's the other thing, right? It's one + + + align:start position:0% +That's the other thing, right? It's one +thing to be to go down, right? slaying + + align:start position:0% +thing to be to go down, right? slaying + + + align:start position:0% +thing to be to go down, right? slaying +the dragon. And it's another thing to be + + align:start position:0% +the dragon. And it's another thing to be + + + align:start position:0% +the dragon. And it's another thing to be +gunned down by machine gun fire having + + align:start position:0% +gunned down by machine gun fire having + + + align:start position:0% +gunned down by machine gun fire having +gone only a few inches, right? And we + + align:start position:0% +gone only a few inches, right? And we + + + align:start position:0% +gone only a few inches, right? And we +can say, gosh, what difference does it + + align:start position:0% +can say, gosh, what difference does it + + + align:start position:0% +can say, gosh, what difference does it +make if you've gone 10 feet or a few + + align:start position:0% +make if you've gone 10 feet or a few + + + align:start position:0% +make if you've gone 10 feet or a few +inches? But maybe it does make a + + align:start position:0% +inches? But maybe it does make a + + + align:start position:0% +inches? But maybe it does make a +difference. Um, but I mean, another + + align:start position:0% +difference. Um, but I mean, another + + + align:start position:0% +difference. Um, but I mean, another +another piece of it is is is class. I + + align:start position:0% +another piece of it is is is class. I + + + align:start position:0% +another piece of it is is is class. I +think that I mean, World War I, the the + + align:start position:0% +think that I mean, World War I, the the + + + align:start position:0% +think that I mean, World War I, the the +boys from Oxford and Cambridge actually + + align:start position:0% +boys from Oxford and Cambridge actually + + + align:start position:0% +boys from Oxford and Cambridge actually +go and they don't come back. And that + + align:start position:0% +go and they don't come back. And that + + + align:start position:0% +go and they don't come back. And that +that's felt very deeply. But hang hang + + align:start position:0% +that's felt very deeply. But hang hang + + + align:start position:0% +that's felt very deeply. But hang hang +on a second, Nick. Okay, so here here is + + align:start position:0% +on a second, Nick. Okay, so here here is + + + align:start position:0% +on a second, Nick. Okay, so here here is +Beaolf getting ready to deliver the + + align:start position:0% +Beaolf getting ready to deliver the + + + align:start position:0% +Beaolf getting ready to deliver the +fatal wound. Once again, the king, + + align:start position:0% +fatal wound. Once again, the king, + + + align:start position:0% +fatal wound. Once again, the king, +that's Beaolf, gathered his strength and + + align:start position:0% +that's Beaolf, gathered his strength and + + + align:start position:0% +that's Beaolf, gathered his strength and +drew his stabbing knife he carried on + + align:start position:0% +drew his stabbing knife he carried on + + + align:start position:0% +drew his stabbing knife he carried on +his belt, sharpened for battle. He stuck + + align:start position:0% +his belt, sharpened for battle. He stuck + + + align:start position:0% +his belt, sharpened for battle. He stuck +it deep in the dragon's flank. Beowolf + + align:start position:0% +it deep in the dragon's flank. Beowolf + + + align:start position:0% +it deep in the dragon's flank. Beowolf +dealt it a deadly wound. They had killed + + align:start position:0% +dealt it a deadly wound. They had killed + + + align:start position:0% +dealt it a deadly wound. They had killed +the enemy. Courage quelled his life. + + align:start position:0% +the enemy. Courage quelled his life. + + + align:start position:0% +the enemy. Courage quelled his life. +That pair of kinsmen, partners and + + align:start position:0% +That pair of kinsmen, partners and + + + align:start position:0% +That pair of kinsmen, partners and +nobility, had destroyed the foe. So + + align:start position:0% +nobility, had destroyed the foe. So + + + align:start position:0% +nobility, had destroyed the foe. So +every man should act be at hand when + + align:start position:0% +every man should act be at hand when + + + align:start position:0% +every man should act be at hand when +needed. This is Wigloff who comes to + + align:start position:0% +needed. This is Wigloff who comes to + + + align:start position:0% +needed. This is Wigloff who comes to +Beaolf's aid and um at the last moment + + align:start position:0% +Beaolf's aid and um at the last moment + + + align:start position:0% +Beaolf's aid and um at the last moment +when he's been deserted by everyone + + align:start position:0% +when he's been deserted by everyone + + + align:start position:0% +when he's been deserted by everyone +else. Okay. So this so every man should + + align:start position:0% +else. Okay. So this so every man should + + + align:start position:0% +else. Okay. So this so every man should +act be at hand when needed. But now for + + align:start position:0% +act be at hand when needed. But now for + + + align:start position:0% +act be at hand when needed. But now for +the king this would be the last of his + + align:start position:0% +the king this would be the last of his + + + align:start position:0% +the king this would be the last of his +many labors and triumphs in the world. + + align:start position:0% +many labors and triumphs in the world. + + + align:start position:0% +many labors and triumphs in the world. +And then we have the wound starting to + + align:start position:0% +And then we have the wound starting to + + + align:start position:0% +And then we have the wound starting to +ooze and do all of the things. Um and + + align:start position:0% +ooze and do all of the things. Um and + + + align:start position:0% +ooze and do all of the things. Um and +then Bea Wolf has to have his dying + + align:start position:0% +then Bea Wolf has to have his dying + + + align:start position:0% +then Bea Wolf has to have his dying +speech, right? because heroes get to + + align:start position:0% +speech, right? because heroes get to + + + align:start position:0% +speech, right? because heroes get to +have dying speeches, but boys being + + align:start position:0% +have dying speeches, but boys being + + + align:start position:0% +have dying speeches, but boys being +killed by machine guns obviously don't + + align:start position:0% +killed by machine guns obviously don't + + + align:start position:0% +killed by machine guns obviously don't +get to have dying speeches. Uh, which is + + align:start position:0% +get to have dying speeches. Uh, which is + + + align:start position:0% +get to have dying speeches. Uh, which is +a problem. Now is the time when I would + + align:start position:0% +a problem. Now is the time when I would + + + align:start position:0% +a problem. Now is the time when I would +have wanted to bestow this armor on my + + align:start position:0% +have wanted to bestow this armor on my + + + align:start position:0% +have wanted to bestow this armor on my +own son. Had it been my fortune to have + + align:start position:0% +own son. Had it been my fortune to have + + + align:start position:0% +own son. Had it been my fortune to have +fathered an heir and live on in his + + align:start position:0% +fathered an heir and live on in his + + + align:start position:0% +fathered an heir and live on in his +flesh. For 50 years, I ruled this + + align:start position:0% +flesh. For 50 years, I ruled this + + + align:start position:0% +flesh. For 50 years, I ruled this +nation. No king of any neighboring clan + + align:start position:0% +nation. No king of any neighboring clan + + + align:start position:0% +nation. No king of any neighboring clan +would dare face me with troops, none had + + align:start position:0% +would dare face me with troops, none had + + + align:start position:0% +would dare face me with troops, none had +the power to intimidate me. I took what + + align:start position:0% +the power to intimidate me. I took what + + + align:start position:0% +the power to intimidate me. I took what +came, cared for and stood by things in + + align:start position:0% +came, cared for and stood by things in + + + align:start position:0% +came, cared for and stood by things in +my keeping, never foremented quarrels, + + align:start position:0% +my keeping, never foremented quarrels, + + + align:start position:0% +my keeping, never foremented quarrels, +never swore to a lie. All this consoles + + align:start position:0% +never swore to a lie. All this consoles + + + align:start position:0% +never swore to a lie. All this consoles +me, doomed as I am, and sickening for + + align:start position:0% +me, doomed as I am, and sickening for + + + align:start position:0% +me, doomed as I am, and sickening for +death. Because of my right ways, the + + align:start position:0% +death. Because of my right ways, the + + + align:start position:0% +death. Because of my right ways, the +ruler of mankind need never blame me + + align:start position:0% +ruler of mankind need never blame me + + + align:start position:0% +ruler of mankind need never blame me +when the breath leaves my body for + + align:start position:0% +when the breath leaves my body for + + + align:start position:0% +when the breath leaves my body for +murder of kinsmen. Go now quickly, + + align:start position:0% +murder of kinsmen. Go now quickly, + + + align:start position:0% +murder of kinsmen. Go now quickly, +dearest Wigloth, under the greystone + + align:start position:0% +dearest Wigloth, under the greystone + + + align:start position:0% +dearest Wigloth, under the greystone +where the dragon is laid out, lost to + + align:start position:0% +where the dragon is laid out, lost to + + + align:start position:0% +where the dragon is laid out, lost to +his treasure. Hurry to feast your eyes + + align:start position:0% +his treasure. Hurry to feast your eyes + + + align:start position:0% +his treasure. Hurry to feast your eyes +on the horde. Away you go. I want to + + align:start position:0% +on the horde. Away you go. I want to + + + align:start position:0% +on the horde. Away you go. I want to +examine that ancient gold. Gaze my fill + + align:start position:0% +examine that ancient gold. Gaze my fill + + + align:start position:0% +examine that ancient gold. Gaze my fill +on those garnered jewels. My going will + + align:start position:0% +on those garnered jewels. My going will + + + align:start position:0% +on those garnered jewels. My going will +be easier for having seen the treasure. + + align:start position:0% +be easier for having seen the treasure. + + + align:start position:0% +be easier for having seen the treasure. +A less troubled letting go of the life + + align:start position:0% +A less troubled letting go of the life + + + align:start position:0% +A less troubled letting go of the life +and lordship I have long maintained. + + align:start position:0% +and lordship I have long maintained. + + + align:start position:0% +and lordship I have long maintained. +Okay, so he's dying and he's worried one + + align:start position:0% +Okay, so he's dying and he's worried one + + + align:start position:0% +Okay, so he's dying and he's worried one +because he doesn't have a son. He was + + align:start position:0% +because he doesn't have a son. He was + + + align:start position:0% +because he doesn't have a son. He was +king for 50 years. Well, he could have + + align:start position:0% +king for 50 years. Well, he could have + + + align:start position:0% +king for 50 years. Well, he could have +done something about that presumably, + + align:start position:0% +done something about that presumably, + + + align:start position:0% +done something about that presumably, +but it didn't occur to him until this + + align:start position:0% +but it didn't occur to him until this + + + align:start position:0% +but it didn't occur to him until this +moment. + + align:start position:0% +moment. + + + align:start position:0% +moment. +And moreover, he wants Wigloff to quick + + align:start position:0% +And moreover, he wants Wigloff to quick + + + align:start position:0% +And moreover, he wants Wigloff to quick +run back to the dragon's lair and get + + align:start position:0% +run back to the dragon's lair and get + + + align:start position:0% +run back to the dragon's lair and get +some of the treasure and bring it back + + align:start position:0% +some of the treasure and bring it back + + + align:start position:0% +some of the treasure and bring it back +so he can see + + align:start position:0% +so he can see + + + align:start position:0% +so he can see +it. Seems maybe to be a silly way to us + + align:start position:0% +it. Seems maybe to be a silly way to us + + + align:start position:0% +it. Seems maybe to be a silly way to us +to spend your dying + + align:start position:0% +to spend your dying + + + align:start position:0% +to spend your dying +moments, right? But it's part of that + + align:start position:0% +moments, right? But it's part of that + + + align:start position:0% +moments, right? But it's part of that +it's part of that heroic mode, right? + + align:start position:0% +it's part of that heroic mode, right? + + + align:start position:0% +it's part of that heroic mode, right? +The whole point of of dying in this way, + + align:start position:0% +The whole point of of dying in this way, + + + align:start position:0% +The whole point of of dying in this way, +the whole point of it is that you've + + align:start position:0% +the whole point of it is that you've + + + align:start position:0% +the whole point of it is that you've +killed the dragon and you've in fact + + align:start position:0% +killed the dragon and you've in fact + + + align:start position:0% +killed the dragon and you've in fact +inherited his treasure. Now, it's true, + + align:start position:0% +inherited his treasure. Now, it's true, + + + align:start position:0% +inherited his treasure. Now, it's true, +you're going to die any moment. Um, but + + align:start position:0% +you're going to die any moment. Um, but + + + align:start position:0% +you're going to die any moment. Um, but +you've got the treasure, right? All of + + align:start position:0% +you've got the treasure, right? All of + + + align:start position:0% +you've got the treasure, right? All of +that fits perfectly into + + align:start position:0% +that fits perfectly into + + + align:start position:0% +that fits perfectly into +um into a, if you will, a classically + + align:start position:0% +um into a, if you will, a classically + + + align:start position:0% +um into a, if you will, a classically +heroic mode, right? And we and we know + + align:start position:0% +heroic mode, right? And we and we know + + + align:start position:0% +heroic mode, right? And we and we know +we know this kind of medieval literature + + align:start position:0% +we know this kind of medieval literature + + + align:start position:0% +we know this kind of medieval literature +and we're fairly comfortable with it. + + align:start position:0% +and we're fairly comfortable with it. + + + align:start position:0% +and we're fairly comfortable with it. +The movie industry is made up of this + + align:start position:0% +The movie industry is made up of this + + + align:start position:0% +The movie industry is made up of this +kind of medieval stuff, right? It's not + + align:start position:0% +kind of medieval stuff, right? It's not + + + align:start position:0% +kind of medieval stuff, right? It's not +made up of the Caroline Walker Binham + + align:start position:0% +made up of the Caroline Walker Binham + + + align:start position:0% +made up of the Caroline Walker Binham +kind of stuff, right? I mean, can you + + align:start position:0% +kind of stuff, right? I mean, can you + + + align:start position:0% +kind of stuff, right? I mean, can you +imagine the great movies of, you know, + + align:start position:0% +imagine the great movies of, you know, + + + align:start position:0% +imagine the great movies of, you know, +saintly women wasting away day by day + + align:start position:0% +saintly women wasting away day by day + + + align:start position:0% +saintly women wasting away day by day +slowly, you know, in penitence to God? + + align:start position:0% +slowly, you know, in penitence to God? + + + align:start position:0% +slowly, you know, in penitence to God? +It just, right? There's no plot, there's + + align:start position:0% +It just, right? There's no plot, there's + + + align:start position:0% +It just, right? There's no plot, there's +no excitement, there's no drama. Um, + + align:start position:0% +no excitement, there's no drama. Um, + + + align:start position:0% +no excitement, there's no drama. Um, +there would only be all of these + + align:start position:0% +there would only be all of these + + + align:start position:0% +there would only be all of these +disturbing questions and nobody would + + align:start position:0% +disturbing questions and nobody would + + + align:start position:0% +disturbing questions and nobody would +pay money to go see it for + + align:start position:0% +pay money to go see it for + + + align:start position:0% +pay money to go see it for +reconciliation with their husband. Stay + + align:start position:0% +reconciliation with their husband. Stay + + + align:start position:0% +reconciliation with their husband. Stay +tuned. + + align:start position:0% +tuned. + + + align:start position:0% +tuned. +The priest sake of communion. Yeah. + + align:start position:0% +The priest sake of communion. Yeah. + + + align:start position:0% +The priest sake of communion. Yeah. +There would be torture, right? There + + align:start position:0% +There would be torture, right? There + + + align:start position:0% +There would be torture, right? There +would be torture. That's true. And some + + align:start position:0% +would be torture. That's true. And some + + + align:start position:0% +would be torture. That's true. And some +people might go in for that, but it + + align:start position:0% +people might go in for that, but it + + + align:start position:0% +people might go in for that, but it +would be a small audience, right, of a + + align:start position:0% +would be a small audience, right, of a + + + align:start position:0% +would be a small audience, right, of a +very of a very particular kind of event. + + align:start position:0% +very of a very particular kind of event. + + + align:start position:0% +very of a very particular kind of event. +The Passion of the Christ is selling + + align:start position:0% +The Passion of the Christ is selling + + + align:start position:0% +The Passion of the Christ is selling +pretty well. Yeah. Passion of the + + align:start position:0% +pretty well. Yeah. Passion of the + + + align:start position:0% +pretty well. Yeah. Passion of the +Christ. I mean, Stigmata sold pretty + + align:start position:0% +Christ. I mean, Stigmata sold pretty + + + align:start position:0% +Christ. I mean, Stigmata sold pretty +good when it came through theaters. Oh, + + align:start position:0% +good when it came through theaters. Oh, + + + align:start position:0% +good when it came through theaters. Oh, +that was that was that was + + align:start position:0% +that was that was that was + + + align:start position:0% +that was that was that was +[Laughter] + + align:start position:0% +[Laughter] + + + align:start position:0% +[Laughter] +all right. All right. We don't want to + + align:start position:0% +all right. All right. We don't want to + + + align:start position:0% +all right. All right. We don't want to +overstate the case, but but + + align:start position:0% +overstate the case, but but + + + align:start position:0% +overstate the case, but but +but clearly there's still a difference + + align:start position:0% +but clearly there's still a difference + + + align:start position:0% +but clearly there's still a difference +in + + align:start position:0% +in + + + align:start position:0% +in +accessibility, right? Okay. But now + + align:start position:0% +accessibility, right? Okay. But now + + + align:start position:0% +accessibility, right? Okay. But now +let's think about the Lord of the + + align:start position:0% +let's think about the Lord of the + + + align:start position:0% +let's think about the Lord of the +Rings. If the heroic mode is part of + + align:start position:0% +Rings. If the heroic mode is part of + + + align:start position:0% +Rings. If the heroic mode is part of +what + + align:start position:0% +what + + + align:start position:0% +what +appeals, who is the hero in the Lord of + + align:start position:0% +appeals, who is the hero in the Lord of + + + align:start position:0% +appeals, who is the hero in the Lord of +the Rings? + + align:start position:0% +the Rings? + + + align:start position:0% +the Rings? +Froto + + align:start position:0% +Froto + + + align:start position:0% +Froto +and Sam, actually Sam is the hero. My + + align:start position:0% +and Sam, actually Sam is the hero. My + + + align:start position:0% +and Sam, actually Sam is the hero. My +bad. Okay. Okay. Anti-hero, so to speak. + + align:start position:0% +bad. Okay. Okay. Anti-hero, so to speak. + + + align:start position:0% +bad. Okay. Okay. Anti-hero, so to speak. +Yeah. What kind of heroes are they? I + + align:start position:0% +Yeah. What kind of heroes are they? I + + + align:start position:0% +Yeah. What kind of heroes are they? I +mean, how does the book end? I mean, + + align:start position:0% +mean, how does the book end? I mean, + + + align:start position:0% +mean, how does the book end? I mean, +there's there's Aragorn. Yeah, there is + + align:start position:0% +there's there's Aragorn. Yeah, there is + + + align:start position:0% +there's there's Aragorn. Yeah, there is +Aragorn. Who is it? Yeah, he gets the + + align:start position:0% +Aragorn. Who is it? Yeah, he gets the + + + align:start position:0% +Aragorn. Who is it? Yeah, he gets the +girl in the end. The girl in the + + align:start position:0% +girl in the end. The girl in the + + + align:start position:0% +girl in the end. The girl in the +kingdom. Okay, that's in the heroic + + align:start position:0% +kingdom. Okay, that's in the heroic + + + align:start position:0% +kingdom. Okay, that's in the heroic +mode. That girl's world is lost. Like he + + align:start position:0% +mode. That girl's world is lost. Like he + + + align:start position:0% +mode. That girl's world is lost. Like he +says it, some wounds never heal. Like he + + align:start position:0% +says it, some wounds never heal. Like he + + + align:start position:0% +says it, some wounds never heal. Like he +rescues the world for everyone else, but + + align:start position:0% +rescues the world for everyone else, but + + + align:start position:0% +rescues the world for everyone else, but +he couldn't rescue it for himself. + + align:start position:0% +he couldn't rescue it for himself. + + + align:start position:0% +he couldn't rescue it for himself. +So, so where should I mean if this book + + align:start position:0% +So, so where should I mean if this book + + + align:start position:0% +So, so where should I mean if this book +was in the heroic mode, shouldn't we + + align:start position:0% +was in the heroic mode, shouldn't we + + + align:start position:0% +was in the heroic mode, shouldn't we +have ended with Aragorn getting the girl + + align:start position:0% +have ended with Aragorn getting the girl + + + align:start position:0% +have ended with Aragorn getting the girl +in the kingdom? Well, how about how + + align:start position:0% +in the kingdom? Well, how about how + + + align:start position:0% +in the kingdom? Well, how about how +about like I mean Beaolf's death, right? + + align:start position:0% +about like I mean Beaolf's death, right? + + + align:start position:0% +about like I mean Beaolf's death, right? +That's that's Froto's Froto's dying in + + align:start position:0% +That's that's Froto's Froto's dying in + + + align:start position:0% +That's that's Froto's Froto's dying in +the in the sense that, you know, he's + + align:start position:0% +the in the sense that, you know, he's + + + align:start position:0% +the in the sense that, you know, he's +going on to the other land where he's + + align:start position:0% +going on to the other land where he's + + + align:start position:0% +going on to the other land where he's +going to die. He's just kind of giving + + align:start position:0% +going to die. He's just kind of giving + + + align:start position:0% +going to die. He's just kind of giving +up and moving on from this world, having + + align:start position:0% +up and moving on from this world, having + + + align:start position:0% +up and moving on from this world, having +performed this great deed, uh saved + + align:start position:0% +performed this great deed, uh saved + + + align:start position:0% +performed this great deed, uh saved +everything for for everyone else. But + + align:start position:0% +everything for for everyone else. But + + + align:start position:0% +everything for for everyone else. But +bewolf, I think, takes us as something + + align:start position:0% +bewolf, I think, takes us as something + + + align:start position:0% +bewolf, I think, takes us as something +where it's, you know, he's done this + + align:start position:0% +where it's, you know, he's done this + + + align:start position:0% +where it's, you know, he's done this +great deed and it's for other people + + align:start position:0% +great deed and it's for other people + + + align:start position:0% +great deed and it's for other people +also, but it's also for him. Like, he's + + align:start position:0% +also, but it's also for him. Like, he's + + + align:start position:0% +also, but it's also for him. Like, he's +done this and, you know, he gets the + + align:start position:0% +done this and, you know, he gets the + + + align:start position:0% +done this and, you know, he gets the +gold afterwards. So, he's gotten what + + align:start position:0% +gold afterwards. So, he's gotten what + + + align:start position:0% +gold afterwards. So, he's gotten what +he's wanted. You know, yeah, he's going + + align:start position:0% +he's wanted. You know, yeah, he's going + + + align:start position:0% +he's wanted. You know, yeah, he's going +to die, but he's gotten what he's + + align:start position:0% +to die, but he's gotten what he's + + + align:start position:0% +to die, but he's gotten what he's +wanted. + + align:start position:0% +wanted. + + + align:start position:0% +wanted. +He gets the praise. Well, you know, + + align:start position:0% +He gets the praise. Well, you know, + + + align:start position:0% +He gets the praise. Well, you know, +Froto's lost both what he wanted like he + + align:start position:0% +Froto's lost both what he wanted like he + + + align:start position:0% +Froto's lost both what he wanted like he +gets he saves the world, but he doesn't + + align:start position:0% +gets he saves the world, but he doesn't + + + align:start position:0% +gets he saves the world, but he doesn't +save, you know, what he really wanted to + + align:start position:0% +save, you know, what he really wanted to + + + align:start position:0% +save, you know, what he really wanted to +save and he didn't so he doesn't really + + align:start position:0% +save and he didn't so he doesn't really + + + align:start position:0% +save and he didn't so he doesn't really +get what he wants. He doesn't get really + + align:start position:0% +get what he wants. He doesn't get really + + + align:start position:0% +get what he wants. He doesn't get really +get the praise. Well, go ahead, Emily. + + align:start position:0% +get the praise. Well, go ahead, Emily. + + + align:start position:0% +get the praise. Well, go ahead, Emily. +But I think there's two really important + + align:start position:0% +But I think there's two really important + + + align:start position:0% +But I think there's two really important +distinctions to draw. Like first of all, + + align:start position:0% +distinctions to draw. Like first of all, + + + align:start position:0% +distinctions to draw. Like first of all, +Bearwolf gets the treasure, right? Froto + + align:start position:0% +Bearwolf gets the treasure, right? Froto + + + align:start position:0% +Bearwolf gets the treasure, right? Froto +spends the whole book trying to get rid + + align:start position:0% +spends the whole book trying to get rid + + + align:start position:0% +spends the whole book trying to get rid +of the treasure. Mhm. And secondly, + + align:start position:0% +of the treasure. Mhm. And secondly, + + + align:start position:0% +of the treasure. Mhm. And secondly, +Beaywolf is an aristocrat. Bearwolf is a + + align:start position:0% +Beaywolf is an aristocrat. Bearwolf is a + + + align:start position:0% +Beaywolf is an aristocrat. Bearwolf is a +king. He's a man of distinction. Frodo + + align:start position:0% +king. He's a man of distinction. Frodo + + + align:start position:0% +king. He's a man of distinction. Frodo +is a hobbit. He's he's of no importance + + align:start position:0% +is a hobbit. He's he's of no importance + + + align:start position:0% +is a hobbit. He's he's of no importance +at all in in global affairs. He has no + + align:start position:0% +at all in in global affairs. He has no + + + align:start position:0% +at all in in global affairs. He has no +family lineage. He's not he's not the + + align:start position:0% +family lineage. He's not he's not the + + + align:start position:0% +family lineage. He's not he's not the +archetypical medieval hero. He's he's no + + align:start position:0% +archetypical medieval hero. He's he's no + + + align:start position:0% +archetypical medieval hero. He's he's no +he's no blue blood. So I think it's + + align:start position:0% +he's no blue blood. So I think it's + + + align:start position:0% +he's no blue blood. So I think it's +there's some really important well + + align:start position:0% +there's some really important well + + + align:start position:0% +there's some really important well +that's where I think the Christian part + + align:start position:0% +that's where I think the Christian part + + + align:start position:0% +that's where I think the Christian part +comes in kind of. It's a like the whole + + align:start position:0% +comes in kind of. It's a like the whole + + + align:start position:0% +comes in kind of. It's a like the whole +like underdog, right? You have the + + align:start position:0% +like underdog, right? You have the + + + align:start position:0% +like underdog, right? You have the +person that no one else would choose + + align:start position:0% +person that no one else would choose + + + align:start position:0% +person that no one else would choose +taking on the task, right? Like Mary and + + align:start position:0% +taking on the task, right? Like Mary and + + + align:start position:0% +taking on the task, right? Like Mary and +Joseph like they get chosen even though + + align:start position:0% +Joseph like they get chosen even though + + + align:start position:0% +Joseph like they get chosen even though +they're at the bottom of the barrel, so + + align:start position:0% +they're at the bottom of the barrel, so + + + align:start position:0% +they're at the bottom of the barrel, so +to speak. And it's always the bottom of + + align:start position:0% +to speak. And it's always the bottom of + + + align:start position:0% +to speak. And it's always the bottom of +the barrel, right? That's like the theme + + align:start position:0% +the barrel, right? That's like the theme + + + align:start position:0% +the barrel, right? That's like the theme +throughout culture. That's our women, + + align:start position:0% +throughout culture. That's our women, + + + align:start position:0% +throughout culture. That's our women, +right, who are um engaged in these, if + + align:start position:0% +right, who are um engaged in these, if + + + align:start position:0% +right, who are um engaged in these, if +you will, anti-heroic feats of + + align:start position:0% +you will, anti-heroic feats of + + + align:start position:0% +you will, anti-heroic feats of +starvation and self mutilation and + + align:start position:0% +starvation and self mutilation and + + + align:start position:0% +starvation and self mutilation and +whatever else, right? They + + align:start position:0% +whatever else, right? They + + + align:start position:0% +whatever else, right? They +are they um are God's ultimate agents + + align:start position:0% +are they um are God's ultimate agents + + + align:start position:0% +are they um are God's ultimate agents +precisely because they are low and it's + + align:start position:0% +precisely because they are low and it's + + + align:start position:0% +precisely because they are low and it's +unexpected. Yeah, Ben, I don't I just + + align:start position:0% +unexpected. Yeah, Ben, I don't I just + + + align:start position:0% +unexpected. Yeah, Ben, I don't I just +wanted to say that uh like to me the + + align:start position:0% +wanted to say that uh like to me the + + + align:start position:0% +wanted to say that uh like to me the +Lord of the Rings isn't just like Froto + + align:start position:0% +Lord of the Rings isn't just like Froto + + + align:start position:0% +Lord of the Rings isn't just like Froto +isn't the main hero cuz like after uh + + align:start position:0% +isn't the main hero cuz like after uh + + + align:start position:0% +isn't the main hero cuz like after uh +the first book the fellowship it's all + + align:start position:0% +the first book the fellowship it's all + + + align:start position:0% +the first book the fellowship it's all +it like ever since I read it has always + + align:start position:0% +it like ever since I read it has always + + + align:start position:0% +it like ever since I read it has always +been two books like it was Froto and Sam + + align:start position:0% +been two books like it was Froto and Sam + + + align:start position:0% +been two books like it was Froto and Sam +like and they even split up into two + + align:start position:0% +like and they even split up into two + + + align:start position:0% +like and they even split up into two +books one's Froto and Sam and both and + + align:start position:0% +books one's Froto and Sam and both and + + + align:start position:0% +books one's Froto and Sam and both and +the other one's like Aragorn and Gimly + + align:start position:0% +the other one's like Aragorn and Gimly + + + align:start position:0% +the other one's like Aragorn and Gimly +and all the elves or everyone else and + + align:start position:0% +and all the elves or everyone else and + + + align:start position:0% +and all the elves or everyone else and +so it was always like yeah there was the + + align:start position:0% +so it was always like yeah there was the + + + align:start position:0% +so it was always like yeah there was the +anti-heroes Froto and him. But in the + + align:start position:0% +anti-heroes Froto and him. But in the + + + align:start position:0% +anti-heroes Froto and him. But in the +book there there was still an complete + + align:start position:0% +book there there was still an complete + + + align:start position:0% +book there there was still an complete +book that was made up of the heroes and + + align:start position:0% +book that was made up of the heroes and + + + align:start position:0% +book that was made up of the heroes and +all the hero quests and that sort of + + align:start position:0% +all the hero quests and that sort of + + + align:start position:0% +all the hero quests and that sort of +stuff. I agree with you. But Tolken puts + + align:start position:0% +stuff. I agree with you. But Tolken puts + + + align:start position:0% +stuff. I agree with you. But Tolken puts +his cards on the table by how he ends, + + align:start position:0% +his cards on the table by how he ends, + + + align:start position:0% +his cards on the table by how he ends, +right? I mean, when when + + align:start position:0% +right? I mean, when when + + + align:start position:0% +right? I mean, when when +when I first read this to um my own kids + + align:start position:0% +when I first read this to um my own kids + + + align:start position:0% +when I first read this to um my own kids +and and you know, of course, too young + + align:start position:0% +and and you know, of course, too young + + + align:start position:0% +and and you know, of course, too young +to properly appreciate it, but you know, + + align:start position:0% +to properly appreciate it, but you know, + + + align:start position:0% +to properly appreciate it, but you know, +couldn't wait. + + align:start position:0% +couldn't wait. + + + align:start position:0% +couldn't wait. +um they wanted more or less to stop + + align:start position:0% +um they wanted more or less to stop + + + align:start position:0% +um they wanted more or less to stop +reading when Aragorn gets crowned. And + + align:start position:0% +reading when Aragorn gets crowned. And + + + align:start position:0% +reading when Aragorn gets crowned. And +that going back to the Shire business, + + align:start position:0% +that going back to the Shire business, + + + align:start position:0% +that going back to the Shire business, +who even wants to read that? Could we + + align:start position:0% +who even wants to read that? Could we + + + align:start position:0% +who even wants to read that? Could we +just skip that part? Well, okay. But + + align:start position:0% +just skip that part? Well, okay. But + + + align:start position:0% +just skip that part? Well, okay. But +there's a totally different sensibility + + align:start position:0% +there's a totally different sensibility + + + align:start position:0% +there's a totally different sensibility +at that point, right? Um, but I think + + align:start position:0% +at that point, right? Um, but I think + + + align:start position:0% +at that point, right? Um, but I think +that I think that + + align:start position:0% +that I think that + + + align:start position:0% +that I think that +Tolken is, you know, when when you when + + align:start position:0% +Tolken is, you know, when when you when + + + align:start position:0% +Tolken is, you know, when when you when +you choose to have two stories running + + align:start position:0% +you choose to have two stories running + + + align:start position:0% +you choose to have two stories running +in parallel and you ultimately decide + + align:start position:0% +in parallel and you ultimately decide + + + align:start position:0% +in parallel and you ultimately decide +that one of them gets the last word, + + align:start position:0% +that one of them gets the last word, + + + align:start position:0% +that one of them gets the last word, +well, that's the one that gets the last + + align:start position:0% +well, that's the one that gets the last + + + align:start position:0% +well, that's the one that gets the last +word. I mean, I think you're I think + + align:start position:0% +word. I mean, I think you're I think + + + align:start position:0% +word. I mean, I think you're I think +you're making a powerful statement + + align:start position:0% +you're making a powerful statement + + + align:start position:0% +you're making a powerful statement +there. We could argue about it, but I + + align:start position:0% +there. We could argue about it, but I + + + align:start position:0% +there. We could argue about it, but I +mean, that's but that's how I would read + + align:start position:0% +mean, that's but that's how I would read + + + align:start position:0% +mean, that's but that's how I would read +that. I don't I don't know who was next. + + align:start position:0% +that. I don't I don't know who was next. + + + align:start position:0% +that. I don't I don't know who was next. +Miranda, I guess um well, two things. It + + align:start position:0% +Miranda, I guess um well, two things. It + + + align:start position:0% +Miranda, I guess um well, two things. It +was I think that what they said in the + + align:start position:0% +was I think that what they said in the + + + align:start position:0% +was I think that what they said in the +article fit more was the whole idea of + + align:start position:0% +article fit more was the whole idea of + + + align:start position:0% +article fit more was the whole idea of +the unsung hero of the World War I and + + align:start position:0% +the unsung hero of the World War I and + + + align:start position:0% +the unsung hero of the World War I and +how this sort of this person who you + + align:start position:0% +how this sort of this person who you + + + align:start position:0% +how this sort of this person who you +know has done a lot of this work just + + align:start position:0% +know has done a lot of this work just + + + align:start position:0% +know has done a lot of this work just +comes back and is you know going look + + align:start position:0% +comes back and is you know going look + + + align:start position:0% +comes back and is you know going look +what I've done and everyone's just so + + align:start position:0% +what I've done and everyone's just so + + + align:start position:0% +what I've done and everyone's just so +has just basically pushes any of this + + align:start position:0% +has just basically pushes any of this + + + align:start position:0% +has just basically pushes any of this +trying to push any of the thought away + + align:start position:0% +trying to push any of the thought away + + + align:start position:0% +trying to push any of the thought away +doesn't really give any of the praise. + + align:start position:0% +doesn't really give any of the praise. + + + align:start position:0% +doesn't really give any of the praise. +Mhm. I also trying to remember cuz I I'd + + align:start position:0% +Mhm. I also trying to remember cuz I I'd + + + align:start position:0% +Mhm. I also trying to remember cuz I I'd +heard I hadn't read the last one at all + + align:start position:0% +heard I hadn't read the last one at all + + + align:start position:0% +heard I hadn't read the last one at all +that in fact in the movie that they cut + + align:start position:0% +that in fact in the movie that they cut + + + align:start position:0% +that in fact in the movie that they cut +out a bunch where like someone had you + + align:start position:0% +out a bunch where like someone had you + + + align:start position:0% +out a bunch where like someone had you +know of going back to the Shire where he + + align:start position:0% +know of going back to the Shire where he + + + align:start position:0% +know of going back to the Shire where he +in + + align:start position:0% +in + + + align:start position:0% +in +fact Son had taken over the Shire and + + align:start position:0% +fact Son had taken over the Shire and + + + align:start position:0% +fact Son had taken over the Shire and +polluted it and stuff like that. Mhm. + + align:start position:0% +polluted it and stuff like that. Mhm. + + + align:start position:0% +polluted it and stuff like that. Mhm. +They've specifically cut that out of the + + align:start position:0% +They've specifically cut that out of the + + + align:start position:0% +They've specifically cut that out of the +movie because people would not be able + + align:start position:0% +movie because people would not be able + + + align:start position:0% +movie because people would not be able +to deal with something like, you know, + + align:start position:0% +to deal with something like, you know, + + + align:start position:0% +to deal with something like, you know, +that and it was already 3 and 1 half + + align:start position:0% +that and it was already 3 and 1 half + + + align:start position:0% +that and it was already 3 and 1 half +hours long or something like that. But + + align:start position:0% +hours long or something like that. But + + + align:start position:0% +hours long or something like that. But +yeah, they filmed that part. But the + + align:start position:0% +yeah, they filmed that part. But the + + + align:start position:0% +yeah, they filmed that part. But the +Shire got taken over in the very first + + align:start position:0% +Shire got taken over in the very first + + + align:start position:0% +Shire got taken over in the very first +book like when they left it. That was + + align:start position:0% +book like when they left it. That was + + + align:start position:0% +book like when they left it. That was +when they first all those + + align:start position:0% +when they first all those + + + align:start position:0% +when they first all those +scourging of + + align:start position:0% +scourging of + + + align:start position:0% +scourging of +the go ahead. But I think to get back to + + align:start position:0% +the go ahead. But I think to get back to + + + align:start position:0% +the go ahead. But I think to get back to +this like hero discussion. So this book + + align:start position:0% +this like hero discussion. So this book + + + align:start position:0% +this like hero discussion. So this book +had such a massive appeal in 40s or 50s + + align:start position:0% +had such a massive appeal in 40s or 50s + + + align:start position:0% +had such a massive appeal in 40s or 50s +or whenever it was published because it + + align:start position:0% +or whenever it was published because it + + + align:start position:0% +or whenever it was published because it +empathized with this unsung hero of + + align:start position:0% +empathized with this unsung hero of + + + align:start position:0% +empathized with this unsung hero of +World War I. Sure. But then why does it + + align:start position:0% +World War I. Sure. But then why does it + + + align:start position:0% +World War I. Sure. But then why does it +have such a wide appeal to us now? And I + + align:start position:0% +have such a wide appeal to us now? And I + + + align:start position:0% +have such a wide appeal to us now? And I +think I'd like to make the contention + + align:start position:0% +think I'd like to make the contention + + + align:start position:0% +think I'd like to make the contention +that it has such a wide appeal because + + align:start position:0% +that it has such a wide appeal because + + + align:start position:0% +that it has such a wide appeal because +like in today's society we don't really + + align:start position:0% +like in today's society we don't really + + + align:start position:0% +like in today's society we don't really +have heroes anymore. And we have to + + align:start position:0% +have heroes anymore. And we have to + + + align:start position:0% +have heroes anymore. And we have to +invent them either like you we we look + + align:start position:0% +invent them either like you we we look + + + align:start position:0% +invent them either like you we we look +for them in fiction because what's like + + align:start position:0% +for them in fiction because what's like + + + align:start position:0% +for them in fiction because what's like +the hero today like Michael Jordan you + + align:start position:0% +the hero today like Michael Jordan you + + + align:start position:0% +the hero today like Michael Jordan you +know like we it's athletes there's no + + align:start position:0% +know like we it's athletes there's no + + + align:start position:0% +know like we it's athletes there's no +what's a societal hero today like we + + align:start position:0% +what's a societal hero today like we + + + align:start position:0% +what's a societal hero today like we +really don't we don't really go around + + align:start position:0% +really don't we don't really go around + + + align:start position:0% +really don't we don't really go around +you said that with such contempt was + + align:start position:0% +you said that with such contempt was + + + align:start position:0% +you said that with such contempt was +wonderful + + align:start position:0% +wonderful + + + align:start position:0% +wonderful +like it's it's really striking like who + + align:start position:0% +like it's it's really striking like who + + + align:start position:0% +like it's it's really striking like who +do little children look up to I don't + + align:start position:0% +do little children look up to I don't + + + align:start position:0% +do little children look up to I don't +know I have no idea who was + + align:start position:0% +know I have no idea who was + + + align:start position:0% +know I have no idea who was +next Peter + + align:start position:0% +next Peter + + + align:start position:0% +next Peter +And how about that? I I do know my mom + + align:start position:0% +And how about that? I I do know my mom + + + align:start position:0% +And how about that? I I do know my mom +first read toolken and all those things + + align:start position:0% +first read toolken and all those things + + + align:start position:0% +first read toolken and all those things +like when she was in her 20s. Mhm. And + + align:start position:0% +like when she was in her 20s. Mhm. And + + + align:start position:0% +like when she was in her 20s. Mhm. And +when she first gave me the book, she was + + align:start position:0% +when she first gave me the book, she was + + + align:start position:0% +when she first gave me the book, she was +like, you know, when I first read these, + + align:start position:0% +like, you know, when I first read these, + + + align:start position:0% +like, you know, when I first read these, +I ended up living in Middle Earth for + + align:start position:0% +I ended up living in Middle Earth for + + + align:start position:0% +I ended up living in Middle Earth for +about 10 years. + + align:start position:0% +about 10 years. + + + align:start position:0% +about 10 years. +For for at least for that generation, + + align:start position:0% +For for at least for that generation, + + + align:start position:0% +For for at least for that generation, +for the 60s7s, their their the main + + align:start position:0% +for the 60s7s, their their the main + + + align:start position:0% +for the 60s7s, their their the main +appeal of the book was that he had + + align:start position:0% +appeal of the book was that he had + + + align:start position:0% +appeal of the book was that he had +created such a real world to them that + + align:start position:0% +created such a real world to them that + + + align:start position:0% +created such a real world to them that +they could actually imagine it being + + align:start position:0% +they could actually imagine it being + + + align:start position:0% +they could actually imagine it being +real, that it be that it became part of + + align:start position:0% +real, that it be that it became part of + + + align:start position:0% +real, that it be that it became part of +their lives. And that's why it it wasn't + + align:start position:0% +their lives. And that's why it it wasn't + + + align:start position:0% +their lives. And that's why it it wasn't +the heroes. It wasn't it wasn't the + + align:start position:0% +the heroes. It wasn't it wasn't the + + + align:start position:0% +the heroes. It wasn't it wasn't the +human part that made them that made them + + align:start position:0% +human part that made them that made them + + + align:start position:0% +human part that made them that made them +believe in that world so much. It was + + align:start position:0% +believe in that world so much. It was + + + align:start position:0% +believe in that world so much. It was +all the other it was all the things that + + align:start position:0% +all the other it was all the things that + + + align:start position:0% +all the other it was all the things that +weren't didn't don't actually exist. The + + align:start position:0% +weren't didn't don't actually exist. The + + + align:start position:0% +weren't didn't don't actually exist. The +hobbits and all these things + + align:start position:0% + + + + align:start position:0% + +actually I know they don't really exist + + align:start position:0% +actually I know they don't really exist + + + align:start position:0% +actually I know they don't really exist +but they did exist in people's minds. He + + align:start position:0% +but they did exist in people's minds. He + + + align:start position:0% +but they did exist in people's minds. He +he created a history that may have been + + align:start position:0% +he created a history that may have been + + + align:start position:0% +he created a history that may have been +completely fiction, but it became but in + + align:start position:0% +completely fiction, but it became but in + + + align:start position:0% +completely fiction, but it became but in +a lot of people's minds it became true + + align:start position:0% +a lot of people's minds it became true + + + align:start position:0% +a lot of people's minds it became true +because it I think in part because when + + align:start position:0% +because it I think in part because when + + + align:start position:0% +because it I think in part because when +we went back earlier that he wrote it + + align:start position:0% +we went back earlier that he wrote it + + + align:start position:0% +we went back earlier that he wrote it +like a history text. Mhm. + + align:start position:0% +like a history text. Mhm. + + + align:start position:0% +like a history text. Mhm. +And I mean obviously one of the things + + align:start position:0% +And I mean obviously one of the things + + + align:start position:0% +And I mean obviously one of the things +that's going on here is the power of an + + align:start position:0% +that's going on here is the power of an + + + align:start position:0% +that's going on here is the power of an +exceedingly gifted writer. Oh, I I it's + + align:start position:0% +exceedingly gifted writer. Oh, I I it's + + + align:start position:0% +exceedingly gifted writer. Oh, I I it's +a contrast. Remember we read the unruded + + align:start position:0% +a contrast. Remember we read the unruded + + + align:start position:0% +a contrast. Remember we read the unruded +captive or Yeah. And I actually said + + align:start position:0% +captive or Yeah. And I actually said + + + align:start position:0% +captive or Yeah. And I actually said +then it was a fictional story that + + align:start position:0% +then it was a fictional story that + + + align:start position:0% +then it was a fictional story that +happened to be true in the way it was + + align:start position:0% +happened to be true in the way it was + + + align:start position:0% +happened to be true in the way it was +written. This is a this is a a fictional + + align:start position:0% +written. This is a this is a a fictional + + + align:start position:0% +written. This is a this is a a fictional +story. I mean this is a historical text + + align:start position:0% +story. I mean this is a historical text + + + align:start position:0% +story. I mean this is a historical text +that happens to be fiction, right? Okay. + + align:start position:0% +that happens to be fiction, right? Okay. + + + align:start position:0% +that happens to be fiction, right? Okay. +I mean I think that's actually I think + + align:start position:0% +I mean I think that's actually I think + + + align:start position:0% +I mean I think that's actually I think +that's actually something Tolken would + + align:start position:0% +that's actually something Tolken would + + + align:start position:0% +that's actually something Tolken would +have been very happy to hear. Um I don't + + align:start position:0% +have been very happy to hear. Um I don't + + + align:start position:0% +have been very happy to hear. Um I don't +even remember what I said. Peter, were + + align:start position:0% +even remember what I said. Peter, were + + + align:start position:0% +even remember what I said. Peter, were +you next? Okay. I can't really speak of + + align:start position:0% +you next? Okay. I can't really speak of + + + align:start position:0% +you next? Okay. I can't really speak of +Tolken as I said. But getting back to + + align:start position:0% +Tolken as I said. But getting back to + + + align:start position:0% +Tolken as I said. But getting back to +the hero discussion, I mean after World + + align:start position:0% +the hero discussion, I mean after World + + + align:start position:0% +the hero discussion, I mean after World +War I, you have you do have the + + align:start position:0% +War I, you have you do have the + + + align:start position:0% +War I, you have you do have the +invention of heroes. If you look at + + align:start position:0% +invention of heroes. If you look at + + + align:start position:0% +invention of heroes. If you look at +World War II, which is right before when + + align:start position:0% +World War II, which is right before when + + + align:start position:0% +World War II, which is right before when +I guess the Lord of the Rings comes out + + align:start position:0% +I guess the Lord of the Rings comes out + + + align:start position:0% +I guess the Lord of the Rings comes out +in the 50s, maybe. Yeah, early 50s. Um, + + align:start position:0% +in the 50s, maybe. Yeah, early 50s. Um, + + + align:start position:0% +in the 50s, maybe. Yeah, early 50s. Um, +who are the heroes on the Coppers of + + align:start position:0% +who are the heroes on the Coppers of + + + align:start position:0% +who are the heroes on the Coppers of +America, you have, you know, Rosie the + + align:start position:0% +America, you have, you know, Rosie the + + + align:start position:0% +America, you have, you know, Rosie the +Riveter? Is she a real person? No, she's + + align:start position:0% +Riveter? Is she a real person? No, she's + + + align:start position:0% +Riveter? Is she a real person? No, she's +this, you know, person that's been + + align:start position:0% +this, you know, person that's been + + + align:start position:0% +this, you know, person that's been +created as a as a sort of this is what + + align:start position:0% +created as a as a sort of this is what + + + align:start position:0% +created as a as a sort of this is what +you should be like. This is your hero. + + align:start position:0% +you should be like. This is your hero. + + + align:start position:0% +you should be like. This is your hero. +You don't you don't have real life + + align:start position:0% +You don't you don't have real life + + + align:start position:0% +You don't you don't have real life +heroes anymore. You have in the Soviet + + align:start position:0% +heroes anymore. You have in the Soviet + + + align:start position:0% +heroes anymore. You have in the Soviet +Union, you have people create I mean, + + align:start position:0% +Union, you have people create I mean, + + + align:start position:0% +Union, you have people create I mean, +it's a different culture. I mean it's a + + align:start position:0% +it's a different culture. I mean it's a + + + align:start position:0% +it's a different culture. I mean it's a +different political culture but you have + + align:start position:0% +different political culture but you have + + + align:start position:0% +different political culture but you have +um like an enemy at the gates which is + + align:start position:0% +um like an enemy at the gates which is + + + align:start position:0% +um like an enemy at the gates which is +based on a true story. You have I mean + + align:start position:0% +based on a true story. You have I mean + + + align:start position:0% +based on a true story. You have I mean +they really pump up Vitalisv as you know + + align:start position:0% +they really pump up Vitalisv as you know + + + align:start position:0% +they really pump up Vitalisv as you know +he is the hero of this war but nobody + + align:start position:0% +he is the hero of this war but nobody + + + align:start position:0% +he is the hero of this war but nobody +would have heard of him if he's not you + + align:start position:0% +would have heard of him if he's not you + + + align:start position:0% +would have heard of him if he's not you +know without propaganda. So I think that + + align:start position:0% +know without propaganda. So I think that + + + align:start position:0% +know without propaganda. So I think that +the creation of a hero in a society + + align:start position:0% +the creation of a hero in a society + + + align:start position:0% +the creation of a hero in a society +where the heroes are lacking is part of + + align:start position:0% +where the heroes are lacking is part of + + + align:start position:0% +where the heroes are lacking is part of +the appeal if I had read this book. + + align:start position:0% +the appeal if I had read this book. + + + align:start position:0% +the appeal if I had read this book. +Yeah. Okay. I it's a good point. The + + align:start position:0% +Yeah. Okay. I it's a good point. The + + + align:start position:0% +Yeah. Okay. I it's a good point. The +heroes are + + align:start position:0% +heroes are + + + align:start position:0% +heroes are +amalgams amalgamations. That's what I + + align:start position:0% +amalgams amalgamations. That's what I + + + align:start position:0% +amalgams amalgamations. That's what I +want to say of of lots of people who fit + + align:start position:0% +want to say of of lots of people who fit + + + align:start position:0% +want to say of of lots of people who fit +a type. And so in some sense, right, + + align:start position:0% +a type. And so in some sense, right, + + + align:start position:0% +a type. And so in some sense, right, +Froto and Sam are the quintessential + + align:start position:0% +Froto and Sam are the quintessential + + + align:start position:0% +Froto and Sam are the quintessential +friendship team. Honorable, true, + + align:start position:0% +friendship team. Honorable, true, + + + align:start position:0% +friendship team. Honorable, true, +steadfast, loyal. They don't have to be + + align:start position:0% +steadfast, loyal. They don't have to be + + + align:start position:0% +steadfast, loyal. They don't have to be +Froto and Sam real. They just have to be + + align:start position:0% +Froto and Sam real. They just have to be + + + align:start position:0% +Froto and Sam real. They just have to be +sort of the Froto Sam friendship type. + + align:start position:0% +sort of the Froto Sam friendship type. + + + align:start position:0% +sort of the Froto Sam friendship type. +And they can be heroic + + align:start position:0% +And they can be heroic + + + align:start position:0% +And they can be heroic +um without being + + align:start position:0% +um without being + + + align:start position:0% +um without being +individuated. I don't know if I'd want + + align:start position:0% +individuated. I don't know if I'd want + + + align:start position:0% +individuated. I don't know if I'd want +to stretch that too far. I think Ian, + + align:start position:0% +to stretch that too far. I think Ian, + + + align:start position:0% +to stretch that too far. I think Ian, +you were next. Um, I just want to make a + + align:start position:0% +you were next. Um, I just want to make a + + + align:start position:0% +you were next. Um, I just want to make a +comment. I think it's kind of funny that + + align:start position:0% +comment. I think it's kind of funny that + + + align:start position:0% +comment. I think it's kind of funny that +the part that he invented that that he + + align:start position:0% +the part that he invented that that he + + + align:start position:0% +the part that he invented that that he +didn't take from the medieval text was + + align:start position:0% +didn't take from the medieval text was + + + align:start position:0% +didn't take from the medieval text was +the the underdog, the unlikely hero. + + align:start position:0% +the the underdog, the unlikely hero. + + + align:start position:0% +the the underdog, the unlikely hero. +Mhm. And that's the part that that has + + align:start position:0% +Mhm. And that's the part that that has + + + align:start position:0% +Mhm. And that's the part that that has +lived on the most from his works cuz + + align:start position:0% +lived on the most from his works cuz + + + align:start position:0% +lived on the most from his works cuz +every sing I read so many fantasy books + + align:start position:0% +every sing I read so many fantasy books + + + align:start position:0% +every sing I read so many fantasy books +when I was when I was a kid and they're + + align:start position:0% +when I was when I was a kid and they're + + + align:start position:0% +when I was when I was a kid and they're +all about, you know, generally about + + align:start position:0% +all about, you know, generally about + + + align:start position:0% +all about, you know, generally about +when they're written for kids. Some + + align:start position:0% +when they're written for kids. Some + + + align:start position:0% +when they're written for kids. Some +young person who, you know, something + + align:start position:0% +young person who, you know, something + + + align:start position:0% +young person who, you know, something +something to do some extraordinary + + align:start position:0% +something to do some extraordinary + + + align:start position:0% +something to do some extraordinary +chance, you know, they save the world + + align:start position:0% +chance, you know, they save the world + + + align:start position:0% +chance, you know, they save the world +and that's what they're all about now. + + align:start position:0% +and that's what they're all about now. + + + align:start position:0% +and that's what they're all about now. +And because I mean I guess that that's I + + align:start position:0% +And because I mean I guess that that's I + + + align:start position:0% +And because I mean I guess that that's I +think part of why it has so much appeals + + align:start position:0% +think part of why it has so much appeals + + + align:start position:0% +think part of why it has so much appeals +because anyone can put themselves in + + align:start position:0% +because anyone can put themselves in + + + align:start position:0% +because anyone can put themselves in +their shoes. And it kind of makes me + + align:start position:0% +their shoes. And it kind of makes me + + + align:start position:0% +their shoes. And it kind of makes me +wonder why to the medievals that that + + align:start position:0% +wonder why to the medievals that that + + + align:start position:0% +wonder why to the medievals that that +didn't that didn't come about already. + + align:start position:0% +didn't that didn't come about already. + + + align:start position:0% +didn't that didn't come about already. +Why was Beaolf the to a peasant or I + + align:start position:0% +Why was Beaolf the to a peasant or I + + + align:start position:0% +Why was Beaolf the to a peasant or I +guess a peasant wouldn't be reading but + + align:start position:0% +guess a peasant wouldn't be reading but + + + align:start position:0% +guess a peasant wouldn't be reading but +even hearing it you know like even + + align:start position:0% +even hearing it you know like even + + + align:start position:0% +even hearing it you know like even +someone who would be told this story. + + align:start position:0% +someone who would be told this story. + + + align:start position:0% +someone who would be told this story. +Why is that so inspiring if you're never + + align:start position:0% +Why is that so inspiring if you're never + + + align:start position:0% +Why is that so inspiring if you're never +going to be able to do it? You know I'm + + align:start position:0% +going to be able to do it? You know I'm + + + align:start position:0% +going to be able to do it? You know I'm +never going to be like Beaolf because of + + align:start position:0% +never going to be like Beaolf because of + + + align:start position:0% +never going to be like Beaolf because of +who I am. Well, maybe your expectation + + align:start position:0% +who I am. Well, maybe your expectation + + + align:start position:0% +who I am. Well, maybe your expectation +isn't that you're the one who's going to + + align:start position:0% +isn't that you're the one who's going to + + + align:start position:0% +isn't that you're the one who's going to +do it. The story is appealing because + + align:start position:0% +do it. The story is appealing because + + + align:start position:0% +do it. The story is appealing because +somebody's going to take care of you. + + align:start position:0% +somebody's going to take care of you. + + + align:start position:0% +somebody's going to take care of you. +That's I mean I mean, why is Bea Wolf + + align:start position:0% +That's I mean I mean, why is Bea Wolf + + + align:start position:0% +That's I mean I mean, why is Bea Wolf +great, right? Okay. He goes first to um + + align:start position:0% +great, right? Okay. He goes first to um + + + align:start position:0% +great, right? Okay. He goes first to um +uh to the land of the Danes to rescue + + align:start position:0% +uh to the land of the Danes to rescue + + + align:start position:0% +uh to the land of the Danes to rescue +them from their little monster problem, + + align:start position:0% +them from their little monster problem, + + + align:start position:0% +them from their little monster problem, +kills Grenle. Then it turns out there's + + align:start position:0% +kills Grenle. Then it turns out there's + + + align:start position:0% +kills Grenle. Then it turns out there's +Grenle's mother, right? And she has to + + align:start position:0% +Grenle's mother, right? And she has to + + + align:start position:0% +Grenle's mother, right? And she has to +be dealt with. So he goes to the depths + + align:start position:0% +be dealt with. So he goes to the depths + + + align:start position:0% +be dealt with. So he goes to the depths +of the sea and fights Grenle's mother, + + align:start position:0% +of the sea and fights Grenle's mother, + + + align:start position:0% +of the sea and fights Grenle's mother, +right? Somehow amazingly not needing + + align:start position:0% +right? Somehow amazingly not needing + + + align:start position:0% +right? Somehow amazingly not needing +oxygen for an extended period of time + + align:start position:0% +oxygen for an extended period of time + + + align:start position:0% +oxygen for an extended period of time +while fighting and swinging a sword and + + align:start position:0% +while fighting and swinging a sword and + + + align:start position:0% +while fighting and swinging a sword and +swinging a club and all this other + + align:start position:0% +swinging a club and all this other + + + align:start position:0% +swinging a club and all this other +stuff. Okay. Right. And then he comes + + align:start position:0% +stuff. Okay. Right. And then he comes + + + align:start position:0% +stuff. Okay. Right. And then he comes +back to Rothgra and says, "Look, okay, + + align:start position:0% +back to Rothgra and says, "Look, okay, + + + align:start position:0% +back to Rothgra and says, "Look, okay, +monster problem solved." And he is he is + + align:start position:0% +monster problem solved." And he is he is + + + align:start position:0% +monster problem solved." And he is he is +gifted, right? that is the gifts of gold + + align:start position:0% +gifted, right? that is the gifts of gold + + + align:start position:0% +gifted, right? that is the gifts of gold +and so forth that are due to the warrior + + align:start position:0% +and so forth that are due to the warrior + + + align:start position:0% +and so forth that are due to the warrior +who has who has um proved himself in + + align:start position:0% +who has who has um proved himself in + + + align:start position:0% +who has who has um proved himself in +battle are all are all given and and + + align:start position:0% +battle are all are all given and and + + + align:start position:0% +battle are all are all given and and +Hothgar is actually a little nervous + + align:start position:0% +Hothgar is actually a little nervous + + + align:start position:0% +Hothgar is actually a little nervous +that Bale wolf's going to want more but + + align:start position:0% +that Bale wolf's going to want more but + + + align:start position:0% +that Bale wolf's going to want more but +he doesn't okay I'm ready to go now back + + align:start position:0% +he doesn't okay I'm ready to go now back + + + align:start position:0% +he doesn't okay I'm ready to go now back +to the land of the gats right he heads + + align:start position:0% +to the land of the gats right he heads + + + align:start position:0% +to the land of the gats right he heads +home and his uncle is still king and he + + align:start position:0% +home and his uncle is still king and he + + + align:start position:0% +home and his uncle is still king and he +reports what he's done and his uncle + + align:start position:0% +reports what he's done and his uncle + + + align:start position:0% +reports what he's done and his uncle +basically says says, "Excellent, right? + + align:start position:0% +basically says says, "Excellent, right? + + + align:start position:0% +basically says says, "Excellent, right? +That's what you should be doing." Um, + + align:start position:0% +That's what you should be doing." Um, + + + align:start position:0% +That's what you should be doing." Um, +and and sure enough, when his uncle + + align:start position:0% +and and sure enough, when his uncle + + + align:start position:0% +and and sure enough, when his uncle +passes on, Beaowolf is made king. Then + + align:start position:0% +passes on, Beaowolf is made king. Then + + + align:start position:0% +passes on, Beaowolf is made king. Then +we fast forward 50 years to the second + + align:start position:0% +we fast forward 50 years to the second + + + align:start position:0% +we fast forward 50 years to the second +main part of the narrative. And we have + + align:start position:0% +main part of the narrative. And we have + + + align:start position:0% +main part of the narrative. And we have +now Beaolf's little monster problem + + align:start position:0% +now Beaolf's little monster problem + + + align:start position:0% +now Beaolf's little monster problem +turns out to be the dragon, right? The + + align:start position:0% +turns out to be the dragon, right? The + + + align:start position:0% +turns out to be the dragon, right? The +dragon is disturbed because somebody + + align:start position:0% +dragon is disturbed because somebody + + + align:start position:0% +dragon is disturbed because somebody +steals a cup. some dingbat who doesn't + + align:start position:0% +steals a cup. some dingbat who doesn't + + + align:start position:0% +steals a cup. some dingbat who doesn't +know that, you know, you steal a dragon, + + align:start position:0% +know that, you know, you steal a dragon, + + + align:start position:0% +know that, you know, you steal a dragon, +a cup, excuse me, from a sleeping dragon + + align:start position:0% +a cup, excuse me, from a sleeping dragon + + + align:start position:0% +a cup, excuse me, from a sleeping dragon +and they're going to know about it, + + align:start position:0% +and they're going to know about it, + + + align:start position:0% +and they're going to know about it, +right? Because they know where every + + align:start position:0% +right? Because they know where every + + + align:start position:0% +right? Because they know where every +last piece of their horde is and what it + + align:start position:0% +last piece of their horde is and what it + + + align:start position:0% +last piece of their horde is and what it +looks like and what it smells like and + + align:start position:0% +looks like and what it smells like and + + + align:start position:0% +looks like and what it smells like and +what it feels like. And if you take + + align:start position:0% +what it feels like. And if you take + + + align:start position:0% +what it feels like. And if you take +something from a dragon, even if he + + align:start position:0% +something from a dragon, even if he + + + align:start position:0% +something from a dragon, even if he +doesn't see you do it, he's going to + + align:start position:0% +doesn't see you do it, he's going to + + + align:start position:0% +doesn't see you do it, he's going to +know all about it. And our friend, the + + align:start position:0% +know all about it. And our friend, the + + + align:start position:0% +know all about it. And our friend, the +peasant, who steals the cup from him, + + align:start position:0% +peasant, who steals the cup from him, + + + align:start position:0% +peasant, who steals the cup from him, +doesn't know this. And then he presents + + align:start position:0% +doesn't know this. And then he presents + + + align:start position:0% +doesn't know this. And then he presents +himself to Beaowolf and says, "Guess + + align:start position:0% +himself to Beaowolf and says, "Guess + + + align:start position:0% +himself to Beaowolf and says, "Guess +what? You have a problem. I've upset a + + align:start position:0% +what? You have a problem. I've upset a + + + align:start position:0% +what? You have a problem. I've upset a +dragon, right? And so Beaolf then has to + + align:start position:0% +dragon, right? And so Beaolf then has to + + + align:start position:0% +dragon, right? And so Beaolf then has to +go and fight the dragon. + + align:start position:0% +go and fight the dragon. + + + align:start position:0% +go and fight the dragon. +Um, if you're a + + align:start position:0% +Um, if you're a + + + align:start position:0% +Um, if you're a +peasant, you don't necessarily want to + + align:start position:0% +peasant, you don't necessarily want to + + + align:start position:0% +peasant, you don't necessarily want to +be + + align:start position:0% + + + + align:start position:0% + +Beaowolf, right? It's not a good job + + align:start position:0% +Beaowolf, right? It's not a good job + + + align:start position:0% +Beaowolf, right? It's not a good job +description. In fact, doom is certain. + + align:start position:0% +description. In fact, doom is certain. + + + align:start position:0% +description. In fact, doom is certain. +We know that from the very beginning of + + align:start position:0% +We know that from the very beginning of + + + align:start position:0% +We know that from the very beginning of +the poem, and we're told over and over + + align:start position:0% +the poem, and we're told over and over + + + align:start position:0% +the poem, and we're told over and over +and over and over again, right? Beaolf's + + align:start position:0% +and over and over again, right? Beaolf's + + + align:start position:0% +and over and over again, right? Beaolf's +day is coming. And and I actually want + + align:start position:0% +day is coming. And and I actually want + + + align:start position:0% +day is coming. And and I actually want +to read a little bit past that passage + + align:start position:0% +to read a little bit past that passage + + + align:start position:0% +to read a little bit past that passage +that I read to you before because + + align:start position:0% +that I read to you before because + + + align:start position:0% +that I read to you before because +because it's easy to think of Beaowolf + + align:start position:0% +because it's easy to think of Beaowolf + + + align:start position:0% +because it's easy to think of Beaowolf +as the hero, but the anti-hero is here + + align:start position:0% +as the hero, but the anti-hero is here + + + align:start position:0% +as the hero, but the anti-hero is here +also. + + align:start position:0% +also. + + + align:start position:0% +also. +Um what came about brought to nothing + + align:start position:0% +Um what came about brought to nothing + + + align:start position:0% +Um what came about brought to nothing +the hopes of the one who had wrongly + + align:start position:0% +the hopes of the one who had wrongly + + + align:start position:0% +the hopes of the one who had wrongly +hidden riches under the rockface. First, + + align:start position:0% +hidden riches under the rockface. First, + + + align:start position:0% +hidden riches under the rockface. First, +the dragon slew that man among men, who + + align:start position:0% +the dragon slew that man among men, who + + + align:start position:0% +the dragon slew that man among men, who +in turn made fearsome amends and settled + + align:start position:0% +in turn made fearsome amends and settled + + + align:start position:0% +in turn made fearsome amends and settled +the feud. Famous for his deeds, a + + align:start position:0% +the feud. Famous for his deeds, a + + + align:start position:0% +the feud. Famous for his deeds, a +warrior may be, but it remains a mystery + + align:start position:0% +warrior may be, but it remains a mystery + + + align:start position:0% +warrior may be, but it remains a mystery +where his life will end when he may no + + align:start position:0% +where his life will end when he may no + + + align:start position:0% +where his life will end when he may no +longer dwell in the meatall among his + + align:start position:0% +longer dwell in the meatall among his + + + align:start position:0% +longer dwell in the meatall among his +own. So it was with Beaolf, when he + + align:start position:0% +own. So it was with Beaolf, when he + + + align:start position:0% +own. So it was with Beaolf, when he +faced the cruelty and cunning of the + + align:start position:0% +faced the cruelty and cunning of the + + + align:start position:0% +faced the cruelty and cunning of the +mound guard, that's the dragon. He + + align:start position:0% +mound guard, that's the dragon. He + + + align:start position:0% +mound guard, that's the dragon. He +himself was ignorant of how his + + align:start position:0% +himself was ignorant of how his + + + align:start position:0% +himself was ignorant of how his +departure from the world would happen. + + align:start position:0% +departure from the world would happen. + + + align:start position:0% +departure from the world would happen. +The highborn chiefs who had buried the + + align:start position:0% +The highborn chiefs who had buried the + + + align:start position:0% +The highborn chiefs who had buried the +treasure declared it until doomsday so a + + align:start position:0% +treasure declared it until doomsday so a + + + align:start position:0% +treasure declared it until doomsday so a +cursed that whoever robbed it would be + + align:start position:0% +cursed that whoever robbed it would be + + + align:start position:0% +cursed that whoever robbed it would be +guilty of wrong and grimly punished for + + align:start position:0% +guilty of wrong and grimly punished for + + + align:start position:0% +guilty of wrong and grimly punished for +their transgression hasped in hell + + align:start position:0% +their transgression hasped in hell + + + align:start position:0% +their transgression hasped in hell +bounds in heathen shrines. Yet Baolf's + + align:start position:0% +bounds in heathen shrines. Yet Baolf's + + + align:start position:0% +bounds in heathen shrines. Yet Baolf's +gaze at the gold treasure when he first + + align:start position:0% +gaze at the gold treasure when he first + + + align:start position:0% +gaze at the gold treasure when he first +saw it had not been selfish. + + align:start position:0% +saw it had not been selfish. + + + align:start position:0% +saw it had not been selfish. +Um, there's a lot of complicated stuff + + align:start position:0% +Um, there's a lot of complicated stuff + + + align:start position:0% +Um, there's a lot of complicated stuff +going on in this passage, but the gist + + align:start position:0% +going on in this passage, but the gist + + + align:start position:0% +going on in this passage, but the gist +of it + + align:start position:0% +of it + + + align:start position:0% +of it +is it remains a mystery where Bea Wolf's + + align:start position:0% +is it remains a mystery where Bea Wolf's + + + align:start position:0% +is it remains a mystery where Bea Wolf's +life will end. This is a little bit + + align:start position:0% +life will end. This is a little bit + + + align:start position:0% +life will end. This is a little bit +anti-heroic. I mean, after + + align:start position:0% +anti-heroic. I mean, after + + + align:start position:0% +anti-heroic. I mean, after +all, he is going to die looking on that + + align:start position:0% +all, he is going to die looking on that + + + align:start position:0% +all, he is going to die looking on that +treasure. He's got the treasure, but not + + align:start position:0% +treasure. He's got the treasure, but not + + + align:start position:0% +treasure. He's got the treasure, but not +for long. And and in fact the whailing + + align:start position:0% +for long. And and in fact the whailing + + + align:start position:0% +for long. And and in fact the whailing +woman at the very end of the poem, her + + align:start position:0% +woman at the very end of the poem, her + + + align:start position:0% +woman at the very end of the poem, her +lamentation is we're + + align:start position:0% +lamentation is we're + + + align:start position:0% +lamentation is we're +doomed because now all the other feuds + + align:start position:0% +doomed because now all the other feuds + + + align:start position:0% +doomed because now all the other feuds +that have been kept at bay because + + align:start position:0% +that have been kept at bay because + + + align:start position:0% +that have been kept at bay because +Beaolf was so big and strong are now all + + align:start position:0% +Beaolf was so big and strong are now all + + + align:start position:0% +Beaolf was so big and strong are now all +going to resurface, right? The Swedes + + align:start position:0% +going to resurface, right? The Swedes + + + align:start position:0% +going to resurface, right? The Swedes +are going to be coming because of this + + align:start position:0% +are going to be coming because of this + + + align:start position:0% +are going to be coming because of this +old feud and the Danes are going to be + + align:start position:0% +old feud and the Danes are going to be + + + align:start position:0% +old feud and the Danes are going to be +coming because of that old feud, right? + + align:start position:0% +coming because of that old feud, right? + + + align:start position:0% +coming because of that old feud, right? +And we're doomed without Beaowolf. We're + + align:start position:0% +And we're doomed without Beaowolf. We're + + + align:start position:0% +And we're doomed without Beaowolf. We're +all going to die. So in fact the final + + align:start position:0% +all going to die. So in fact the final + + + align:start position:0% +all going to die. So in fact the final +note of this is I think ultimately much + + align:start position:0% +note of this is I think ultimately much + + + align:start position:0% +note of this is I think ultimately much +more depressing even than the final note + + align:start position:0% +more depressing even than the final note + + + align:start position:0% +more depressing even than the final note +of the Shire uh which is that Froto has + + align:start position:0% +of the Shire uh which is that Froto has + + + align:start position:0% +of the Shire uh which is that Froto has +to leave right but it has been saved for + + align:start position:0% +to leave right but it has been saved for + + + align:start position:0% +to leave right but it has been saved for +everybody else. Yeah Miranda I mean I + + align:start position:0% +everybody else. Yeah Miranda I mean I + + + align:start position:0% +everybody else. Yeah Miranda I mean I +understand the underdog thing with you + + align:start position:0% +understand the underdog thing with you + + + align:start position:0% +understand the underdog thing with you +know life there's a lot of fantasy stuff + + align:start position:0% +know life there's a lot of fantasy stuff + + + align:start position:0% +know life there's a lot of fantasy stuff +where you know there's the underdog and + + align:start position:0% +where you know there's the underdog and + + + align:start position:0% +where you know there's the underdog and +you want to be them but do you really + + align:start position:0% +you want to be them but do you really + + + align:start position:0% +you want to be them but do you really +want to be Frodo? I mean, you see what + + align:start position:0% +want to be Frodo? I mean, you see what + + + align:start position:0% +want to be Frodo? I mean, you see what +happens to him. Not just, you know, all + + align:start position:0% +happens to him. Not just, you know, all + + + align:start position:0% +happens to him. Not just, you know, all +he does is go, you know, he doesn't get + + align:start position:0% +he does is go, you know, he doesn't get + + + align:start position:0% +he does is go, you know, he doesn't get +anything good with, you know, all he + + align:start position:0% +anything good with, you know, all he + + + align:start position:0% +anything good with, you know, all he +does is go through torments, go through + + align:start position:0% +does is go through torments, go through + + + align:start position:0% +does is go through torments, go through +pain, go, you know, he doesn't have + + align:start position:0% +pain, go, you know, he doesn't have + + + align:start position:0% +pain, go, you know, he doesn't have +anything good among this at all. And so, + + align:start position:0% +anything good among this at all. And so, + + + align:start position:0% +anything good among this at all. And so, +it's sort of not really someone you want + + align:start position:0% +it's sort of not really someone you want + + + align:start position:0% +it's sort of not really someone you want +to be. The other problem I have is I've + + align:start position:0% +to be. The other problem I have is I've + + + align:start position:0% +to be. The other problem I have is I've +heard the story of, you know, well, we + + align:start position:0% +heard the story of, you know, well, we + + + align:start position:0% +heard the story of, you know, well, we +don't have heroes nowadays ever anymore. + + align:start position:0% +don't have heroes nowadays ever anymore. + + + align:start position:0% +don't have heroes nowadays ever anymore. +How much did they have heroes back then + + align:start position:0% +How much did they have heroes back then + + + align:start position:0% +How much did they have heroes back then +either? I mean there's you know God is + + align:start position:0% +either? I mean there's you know God is + + + align:start position:0% +either? I mean there's you know God is +the you know a hero but is it always you + + align:start position:0% +the you know a hero but is it always you + + + align:start position:0% +the you know a hero but is it always you +know the hero is something that's past + + align:start position:0% +know the hero is something that's past + + + align:start position:0% +know the hero is something that's past +you know is always something you know + + align:start position:0% +you know is always something you know + + + align:start position:0% +you know is always something you know +there's Beaolf as the hero is there + + align:start position:0% +there's Beaolf as the hero is there + + + align:start position:0% +there's Beaolf as the hero is there +really you know at the time of Beaolf + + align:start position:0% +really you know at the time of Beaolf + + + align:start position:0% +really you know at the time of Beaolf +were there you know kings that were + + align:start position:0% +were there you know kings that were + + + align:start position:0% +were there you know kings that were +thought of as you are the hero you're + + align:start position:0% +thought of as you are the hero you're + + + align:start position:0% +thought of as you are the hero you're +completely you know stuff like that like + + align:start position:0% +completely you know stuff like that like + + + align:start position:0% +completely you know stuff like that like +has there always been you know well + + align:start position:0% +has there always been you know well + + + align:start position:0% +has there always been you know well +there's no heroes of our time there's + + align:start position:0% +there's no heroes of our time there's + + + align:start position:0% +there's no heroes of our time there's +only fictional ones I mean the king used + + align:start position:0% +only fictional ones I mean the king used + + + align:start position:0% +only fictional ones I mean the king used +to get on his horse and lead his troops + + align:start position:0% +to get on his horse and lead his troops + + + align:start position:0% +to get on his horse and lead his troops +into battle in the 30 years war I mean + + align:start position:0% +into battle in the 30 years war I mean + + + align:start position:0% +into battle in the 30 years war I mean +Gustavos Adulus led the Swedish troops + + align:start position:0% +Gustavos Adulus led the Swedish troops + + + align:start position:0% +Gustavos Adulus led the Swedish troops +and he died, you know, in battle and he + + align:start position:0% +and he died, you know, in battle and he + + + align:start position:0% +and he died, you know, in battle and he +didn't die in battle. + + align:start position:0% +didn't die in battle. + + + align:start position:0% +didn't die in battle. +Wait, didn't he die in battle? No, he + + align:start position:0% +Wait, didn't he die in battle? No, he + + + align:start position:0% +Wait, didn't he die in battle? No, he +died. Well, he won. Let's see. He won + + align:start position:0% +died. Well, he won. Let's see. He won + + + align:start position:0% +died. Well, he won. Let's see. He won +his battle and then he sort of meandered + + align:start position:0% +his battle and then he sort of meandered + + + align:start position:0% +his battle and then he sort of meandered +off into the woods from the camp later + + align:start position:0% +off into the woods from the camp later + + + align:start position:0% +off into the woods from the camp later +that day and got killed in the woods. + + align:start position:0% +that day and got killed in the woods. + + + align:start position:0% +that day and got killed in the woods. +So, that's kind of like dying in battle, + + align:start position:0% +So, that's kind of like dying in battle, + + + align:start position:0% +So, that's kind of like dying in battle, +but not exactly. Well, I mean, he's I + + align:start position:0% +but not exactly. Well, I mean, he's I + + + align:start position:0% +but not exactly. Well, I mean, he's I +mean, I went to Sweden. There's statues + + align:start position:0% +mean, I went to Sweden. There's statues + + + align:start position:0% +mean, I went to Sweden. There's statues +of a metal. I mean, he's venerated. + + align:start position:0% +of a metal. I mean, he's venerated. + + + align:start position:0% +of a metal. I mean, he's venerated. +Absolutely. But, I mean, absolutely. + + align:start position:0% +Absolutely. But, I mean, absolutely. + + + align:start position:0% +Absolutely. But, I mean, absolutely. +during the warfare was different back + + align:start position:0% +during the warfare was different back + + + align:start position:0% +during the warfare was different back +when you know Kings League crusades um + + align:start position:0% +when you know Kings League crusades um + + + align:start position:0% +when you know Kings League crusades um +you know I'm going to you know the the + + align:start position:0% +you know I'm going to you know the the + + + align:start position:0% +you know I'm going to you know the the +War of the Roses you know you got No for + + align:start position:0% +War of the Roses you know you got No for + + + align:start position:0% +War of the Roses you know you got No for +sure I mean Charlemagne campaigned + + align:start position:0% +sure I mean Charlemagne campaigned + + + align:start position:0% +sure I mean Charlemagne campaigned +against the Saxons for 30 straight + + align:start position:0% +against the Saxons for 30 straight + + + align:start position:0% +against the Saxons for 30 straight +summers and he did it right for 30 + + align:start position:0% +summers and he did it right for 30 + + + align:start position:0% +summers and he did it right for 30 +straight summers + + align:start position:0% +straight summers + + + align:start position:0% +straight summers +even as just a national guard so + + align:start position:0% + + + + align:start position:0% + +and he was a tall guy too. Um there I + + align:start position:0% +and he was a tall guy too. Um there I + + + align:start position:0% +and he was a tall guy too. Um there I +mean this this I think Annie you made + + align:start position:0% +mean this this I think Annie you made + + + align:start position:0% +mean this this I think Annie you made +this point a little earlier but at some + + align:start position:0% +this point a little earlier but at some + + + align:start position:0% +this point a little earlier but at some +point we have to get the Christianity + + align:start position:0% +point we have to get the Christianity + + + align:start position:0% +point we have to get the Christianity +back in right because that mean + + align:start position:0% +back in right because that mean + + + align:start position:0% +back in right because that mean +obviously in in Beaowolf that's a + + align:start position:0% +obviously in in Beaowolf that's a + + + align:start position:0% +obviously in in Beaowolf that's a +critical piece right the author of the + + align:start position:0% +critical piece right the author of the + + + align:start position:0% +critical piece right the author of the +poem the text is + + align:start position:0% +poem the text is + + + align:start position:0% +poem the text is +Christian the text is um is a presumably + + align:start position:0% +Christian the text is um is a presumably + + + align:start position:0% +Christian the text is um is a presumably +oral tradition story that is not + + align:start position:0% +oral tradition story that is not + + + align:start position:0% +oral tradition story that is not +Christian. There's no ambiguity. Beyolf + + align:start position:0% +Christian. There's no ambiguity. Beyolf + + + align:start position:0% +Christian. There's no ambiguity. Beyolf +isn't ever um misunderstanding himself + + align:start position:0% +isn't ever um misunderstanding himself + + + align:start position:0% +isn't ever um misunderstanding himself +to be a Christian, right? He's very + + align:start position:0% +to be a Christian, right? He's very + + + align:start position:0% +to be a Christian, right? He's very +clear about who he is, but the author of + + align:start position:0% +clear about who he is, but the author of + + + align:start position:0% +clear about who he is, but the author of +the poem, our writer is a Christian. And + + align:start position:0% +the poem, our writer is a Christian. And + + + align:start position:0% +the poem, our writer is a Christian. And +so this tension is just present all the + + align:start position:0% +so this tension is just present all the + + + align:start position:0% +so this tension is just present all the +way throughout. uh and and clearly for + + align:start position:0% +way throughout. uh and and clearly for + + + align:start position:0% +way throughout. uh and and clearly for +Tolken and Lewis both + + align:start position:0% +Tolken and Lewis both + + + align:start position:0% +Tolken and Lewis both +they're they're + + align:start position:0% +they're they're + + + align:start position:0% +they're they're +intense experiences with Christian + + align:start position:0% +intense experiences with Christian + + + align:start position:0% +intense experiences with Christian +theology, right? And in Lewis's case, I + + align:start position:0% +theology, right? And in Lewis's case, I + + + align:start position:0% +theology, right? And in Lewis's case, I +mean really intense, you know, he's I + + align:start position:0% +mean really intense, you know, he's I + + + align:start position:0% +mean really intense, you know, he's I +mean half of his output is + + align:start position:0% +mean half of his output is + + + align:start position:0% +mean half of his output is +apologetics, right? He's not just a, you + + align:start position:0% +apologetics, right? He's not just a, you + + + align:start position:0% +apologetics, right? He's not just a, you +know, kind of an accidental Christian. + + align:start position:0% +know, kind of an accidental Christian. + + + align:start position:0% +know, kind of an accidental Christian. +He's a really serious serious one. And I + + align:start position:0% +He's a really serious serious one. And I + + + align:start position:0% +He's a really serious serious one. And I +mean, and so and so is Tolken, but but + + align:start position:0% +mean, and so and so is Tolken, but but + + + align:start position:0% +mean, and so and so is Tolken, but but +not in the sense that he's actually + + align:start position:0% +not in the sense that he's actually + + + align:start position:0% +not in the sense that he's actually +writing apologetics. Uh but but for both + + align:start position:0% +writing apologetics. Uh but but for both + + + align:start position:0% +writing apologetics. Uh but but for both +of these men uh whatever it was they + + align:start position:0% +of these men uh whatever it was they + + + align:start position:0% +of these men uh whatever it was they +were picking up from the past then had + + align:start position:0% +were picking up from the past then had + + + align:start position:0% +were picking up from the past then had +to be tempered by by what they believe + + align:start position:0% +to be tempered by by what they believe + + + align:start position:0% +to be tempered by by what they believe +to be truth, right? With a capital + + align:start position:0% +to be truth, right? With a capital + + + align:start position:0% +to be truth, right? With a capital +T, you know, getting back to that math + + align:start position:0% +T, you know, getting back to that math + + + align:start position:0% +T, you know, getting back to that math +problem. Um and and let me let me read + + align:start position:0% +problem. Um and and let me let me read + + + align:start position:0% +problem. Um and and let me let me read +you one other source that you probably + + align:start position:0% +you one other source that you probably + + + align:start position:0% +you one other source that you probably +don't just sort of have rolling around + + align:start position:0% +don't just sort of have rolling around + + + align:start position:0% +don't just sort of have rolling around +in your head. + + align:start position:0% +in your head. + + + align:start position:0% +in your head. +Um that has to do with this problem of + + align:start position:0% +Um that has to do with this problem of + + + align:start position:0% +Um that has to do with this problem of +the + + align:start position:0% +the + + + align:start position:0% +the +warrior. Um this is uh the venerable + + align:start position:0% +warrior. Um this is uh the venerable + + + align:start position:0% +warrior. Um this is uh the venerable +bead as they call him his ecclesiastical + + align:start position:0% +bead as they call him his ecclesiastical + + + align:start position:0% +bead as they call him his ecclesiastical +history of the English people. It's a um + + align:start position:0% +history of the English people. It's a um + + + align:start position:0% +history of the English people. It's a um +early 8th century text to be a little + + align:start position:0% +early 8th century text to be a little + + + align:start position:0% +early 8th century text to be a little +bit ahead of the probably depending on + + align:start position:0% +bit ahead of the probably depending on + + + align:start position:0% +bit ahead of the probably depending on +how we date beolf a little bit ahead of + + align:start position:0% +how we date beolf a little bit ahead of + + + align:start position:0% +how we date beolf a little bit ahead of +the writing of Beaolf but you know in + + align:start position:0% +the writing of Beaolf but you know in + + + align:start position:0% +the writing of Beaolf but you know in +that in that Anglo-Saxon world. And this + + align:start position:0% +that in that Anglo-Saxon world. And this + + + align:start position:0% +that in that Anglo-Saxon world. And this +is Bead's + + align:start position:0% +is Bead's + + + align:start position:0% +is Bead's +story about how Edwin of North Umbrea is + + align:start position:0% +story about how Edwin of North Umbrea is + + + align:start position:0% +story about how Edwin of North Umbrea is +converted to Christianity. + + align:start position:0% +converted to Christianity. + + + align:start position:0% +converted to Christianity. +Okay. So Edwin holds a council um the + + align:start position:0% +Okay. So Edwin holds a council um the + + + align:start position:0% +Okay. So Edwin holds a council um the +king answered when he's he's listening + + align:start position:0% +king answered when he's he's listening + + + align:start position:0% +king answered when he's he's listening +to a priest um that it was his will as + + align:start position:0% +to a priest um that it was his will as + + + align:start position:0% +to a priest um that it was his will as +well as his duty to accept the faith + + align:start position:0% +well as his duty to accept the faith + + + align:start position:0% +well as his duty to accept the faith +that Paulus that's the priest taught but + + align:start position:0% +that Paulus that's the priest taught but + + + align:start position:0% +that Paulus that's the priest taught but +said that he must first still discuss + + align:start position:0% +said that he must first still discuss + + + align:start position:0% +said that he must first still discuss +the matter with his principal adviserss + + align:start position:0% +the matter with his principal adviserss + + + align:start position:0% +the matter with his principal adviserss +and friends. Right? Right. So, this is + + align:start position:0% +and friends. Right? Right. So, this is + + + align:start position:0% +and friends. Right? Right. So, this is +the Anglo-Saxon mode. He's got to call + + align:start position:0% +the Anglo-Saxon mode. He's got to call + + + align:start position:0% +the Anglo-Saxon mode. He's got to call +his things together. They're going to + + align:start position:0% +his things together. They're going to + + + align:start position:0% +his things together. They're going to +talk about this. So, I'm persuaded + + align:start position:0% +talk about this. So, I'm persuaded + + + align:start position:0% +talk about this. So, I'm persuaded +that's all well and good, but we're not + + align:start position:0% +that's all well and good, but we're not + + + align:start position:0% +that's all well and good, but we're not +going to be Christians unless we're all + + align:start position:0% +going to be Christians unless we're all + + + align:start position:0% +going to be Christians unless we're all +going to do it together. The the Clovis + + align:start position:0% +going to do it together. The the Clovis + + + align:start position:0% +going to do it together. The the Clovis +conversion story is exactly the same. + + align:start position:0% +conversion story is exactly the same. + + + align:start position:0% +conversion story is exactly the same. +Um, if you've read Gregory of Tour's + + align:start position:0% +Um, if you've read Gregory of Tour's + + + align:start position:0% +Um, if you've read Gregory of Tour's +History of the Franks, okay? So, that if + + align:start position:0% +History of the Franks, okay? So, that if + + + align:start position:0% +History of the Franks, okay? So, that if +they were all in agreement, they might + + align:start position:0% +they were all in agreement, they might + + + align:start position:0% +they were all in agreement, they might +all be cleansed together in Christ. Paul + + align:start position:0% +all be cleansed together in Christ. Paul + + + align:start position:0% +all be cleansed together in Christ. Paul +agrees. The king keeps his promise. He + + align:start position:0% +agrees. The king keeps his promise. He + + + align:start position:0% +agrees. The king keeps his promise. He +summons the council. Okay? and he asks + + align:start position:0% +summons the council. Okay? and he asks + + + align:start position:0% +summons the council. Okay? and he asks +them, "What do you think of this strange + + align:start position:0% +them, "What do you think of this strange + + + align:start position:0% +them, "What do you think of this strange +doctrine and this new way of worshiping + + align:start position:0% +doctrine and this new way of worshiping + + + align:start position:0% +doctrine and this new way of worshiping +the godhead that is being proclaimed to + + align:start position:0% +the godhead that is being proclaimed to + + + align:start position:0% +the godhead that is being proclaimed to +us?" Kofi, the chief priest, replied + + align:start position:0% +us?" Kofi, the chief priest, replied + + + align:start position:0% +us?" Kofi, the chief priest, replied +without hesitation. Now, this is quite a + + align:start position:0% +without hesitation. Now, this is quite a + + + align:start position:0% +without hesitation. Now, this is quite a +wild speech, thinking this is the pagan + + align:start position:0% +wild speech, thinking this is the pagan + + + align:start position:0% +wild speech, thinking this is the pagan +chief priest, mind you. Your majesty, + + align:start position:0% +chief priest, mind you. Your majesty, + + + align:start position:0% +chief priest, mind you. Your majesty, +let us give careful consideration to + + align:start position:0% +let us give careful consideration to + + + align:start position:0% +let us give careful consideration to +this new teaching, for I frankly admit + + align:start position:0% +this new teaching, for I frankly admit + + + align:start position:0% +this new teaching, for I frankly admit +that in my experience, the religion that + + align:start position:0% +that in my experience, the religion that + + + align:start position:0% +that in my experience, the religion that +we have hitherto professed seems + + align:start position:0% +we have hitherto professed seems + + + align:start position:0% +we have hitherto professed seems +valueless and powerless. None of your + + align:start position:0% +valueless and powerless. None of your + + + align:start position:0% +valueless and powerless. None of your +subjects has been more devoted to the + + align:start position:0% +subjects has been more devoted to the + + + align:start position:0% +subjects has been more devoted to the +service of our gods than myself. Yet + + align:start position:0% +service of our gods than myself. Yet + + + align:start position:0% +service of our gods than myself. Yet +there are many to whom you show greater + + align:start position:0% +there are many to whom you show greater + + + align:start position:0% +there are many to whom you show greater +favor, who receive greater honors, and + + align:start position:0% +favor, who receive greater honors, and + + + align:start position:0% +favor, who receive greater honors, and +who are more successful. Now, if the + + align:start position:0% +who are more successful. Now, if the + + + align:start position:0% +who are more successful. Now, if the +gods had any power, they would surely + + align:start position:0% +gods had any power, they would surely + + + align:start position:0% +gods had any power, they would surely +have favored myself, who have been more + + align:start position:0% +have favored myself, who have been more + + + align:start position:0% +have favored myself, who have been more +zealous in their service. Therefore, I + + align:start position:0% +zealous in their service. Therefore, I + + + align:start position:0% +zealous in their service. Therefore, I +love the therefore, you know, it all + + align:start position:0% +love the therefore, you know, it all + + + align:start position:0% +love the therefore, you know, it all +just follows logically. If on + + align:start position:0% +just follows logically. If on + + + align:start position:0% +just follows logically. If on +examination you perceive that these new + + align:start position:0% +examination you perceive that these new + + + align:start position:0% +examination you perceive that these new +teachings are better and more effectual, + + align:start position:0% +teachings are better and more effectual, + + + align:start position:0% +teachings are better and more effectual, +let us not hesitate to accept + + align:start position:0% +let us not hesitate to accept + + + align:start position:0% +let us not hesitate to accept +them. Okay? You know, we're all + + align:start position:0% +them. Okay? You know, we're all + + + align:start position:0% +them. Okay? You know, we're all +thinking, "Yeah, that's a likely story." + + align:start position:0% +thinking, "Yeah, that's a likely story." + + + align:start position:0% +thinking, "Yeah, that's a likely story." +Okay. Another of the king's chief men + + align:start position:0% +Okay. Another of the king's chief men + + + align:start position:0% +Okay. Another of the king's chief men +signified his agreement with this + + align:start position:0% +signified his agreement with this + + + align:start position:0% +signified his agreement with this +prudent argument and went on to say, + + align:start position:0% +prudent argument and went on to say, + + + align:start position:0% +prudent argument and went on to say, +"Your majesty, when we compare the + + align:start position:0% +"Your majesty, when we compare the + + + align:start position:0% +"Your majesty, when we compare the +present life of man on earth with that + + align:start position:0% +present life of man on earth with that + + + align:start position:0% +present life of man on earth with that +time of which we have no knowledge, it + + align:start position:0% +time of which we have no knowledge, it + + + align:start position:0% +time of which we have no knowledge, it +seems to me like the swift flight of a + + align:start position:0% +seems to me like the swift flight of a + + + align:start position:0% +seems to me like the swift flight of a +single sparrow through the banqueting + + align:start position:0% +single sparrow through the banqueting + + + align:start position:0% +single sparrow through the banqueting +hall where you are sitting at dinner on + + align:start position:0% +hall where you are sitting at dinner on + + + align:start position:0% +hall where you are sitting at dinner on +a winter's day with your fangs and + + align:start position:0% +a winter's day with your fangs and + + + align:start position:0% +a winter's day with your fangs and +counselors. In the midst there is a + + align:start position:0% +counselors. In the midst there is a + + + align:start position:0% +counselors. In the midst there is a +comforting fire to warm the hall. + + align:start position:0% +comforting fire to warm the hall. + + + align:start position:0% +comforting fire to warm the hall. +Outside the storms of winter rain or + + align:start position:0% +Outside the storms of winter rain or + + + align:start position:0% +Outside the storms of winter rain or +snow are raging. The sparrow flies + + align:start position:0% +snow are raging. The sparrow flies + + + align:start position:0% +snow are raging. The sparrow flies +swiftly in through one door of the hall + + align:start position:0% +swiftly in through one door of the hall + + + align:start position:0% +swiftly in through one door of the hall +and out through another. While he is + + align:start position:0% +and out through another. While he is + + + align:start position:0% +and out through another. While he is +inside, he is safe from the winter + + align:start position:0% +inside, he is safe from the winter + + + align:start position:0% +inside, he is safe from the winter +storms. But after a few moments of + + align:start position:0% +storms. But after a few moments of + + + align:start position:0% +storms. But after a few moments of +comfort, he vanishes from sight into the + + align:start position:0% +comfort, he vanishes from sight into the + + + align:start position:0% +comfort, he vanishes from sight into the +wintry world from which he came. Even + + align:start position:0% +wintry world from which he came. Even + + + align:start position:0% +wintry world from which he came. Even +so, man appears on earth for a little + + align:start position:0% +so, man appears on earth for a little + + + align:start position:0% +so, man appears on earth for a little +while. But of what went before this life + + align:start position:0% +while. But of what went before this life + + + align:start position:0% +while. But of what went before this life +or of what follows, we know nothing. + + align:start position:0% +or of what follows, we know nothing. + + + align:start position:0% +or of what follows, we know nothing. +Therefore, again, the logic is + + align:start position:0% +Therefore, again, the logic is + + + align:start position:0% +Therefore, again, the logic is +impeccable. If this new teaching has + + align:start position:0% +impeccable. If this new teaching has + + + align:start position:0% +impeccable. If this new teaching has +brought any more certain knowledge, it + + align:start position:0% +brought any more certain knowledge, it + + + align:start position:0% +brought any more certain knowledge, it +seems only right that we should follow + + align:start position:0% +seems only right that we should follow + + + align:start position:0% +seems only right that we should follow +it. I mean, it's a it's a fabulous + + align:start position:0% +it. I mean, it's a it's a fabulous + + + align:start position:0% +it. I mean, it's a it's a fabulous +story. Whether you believe that Edwin + + align:start position:0% +story. Whether you believe that Edwin + + + align:start position:0% +story. Whether you believe that Edwin +really threw a council and this is what + + align:start position:0% +really threw a council and this is what + + + align:start position:0% +really threw a council and this is what +these guys just spontaneously said, I + + align:start position:0% +these guys just spontaneously said, I + + + align:start position:0% +these guys just spontaneously said, I +don't know. But it parallels the Beaalth + + align:start position:0% +don't know. But it parallels the Beaalth + + + align:start position:0% +don't know. But it parallels the Beaalth +ending really well, right? What's going + + align:start position:0% +ending really well, right? What's going + + + align:start position:0% +ending really well, right? What's going +to happen when you pass out of your meat + + align:start position:0% +to happen when you pass out of your meat + + + align:start position:0% +to happen when you pass out of your meat +hole and into the world you don't know + + align:start position:0% +hole and into the world you don't know + + + align:start position:0% +hole and into the world you don't know +about, right? And in that world, + + align:start position:0% +about, right? And in that world, + + + align:start position:0% +about, right? And in that world, +everything is uncertain and totally + + align:start position:0% +everything is uncertain and totally + + + align:start position:0% +everything is uncertain and totally +anti-heroic, right? Whatever you've + + align:start position:0% +anti-heroic, right? Whatever you've + + + align:start position:0% +anti-heroic, right? Whatever you've +achieved here, whatever monsters you've + + align:start position:0% +achieved here, whatever monsters you've + + + align:start position:0% +achieved here, whatever monsters you've +defeated, whatever dragons you've slain, + + align:start position:0% +defeated, whatever dragons you've slain, + + + align:start position:0% +defeated, whatever dragons you've slain, +ultimately they amount to nothing + + align:start position:0% +ultimately they amount to nothing + + + align:start position:0% +ultimately they amount to nothing +because you have no idea what's going to + + align:start position:0% +because you have no idea what's going to + + + align:start position:0% +because you have no idea what's going to +happen next. Now, think + + align:start position:0% +happen next. Now, think + + + align:start position:0% +happen next. Now, think +about think about these sort of, you + + align:start position:0% +about think about these sort of, you + + + align:start position:0% +about think about these sort of, you +know, these are proper historical + + align:start position:0% +know, these are proper historical + + + align:start position:0% +know, these are proper historical +documents, right? Written by + + align:start position:0% + + + + align:start position:0% + +Anglo-Saxons. Now, think about an + + align:start position:0% +Anglo-Saxons. Now, think about an + + + align:start position:0% +Anglo-Saxons. Now, think about an +improper historical document. Let's + + align:start position:0% +improper historical document. Let's + + + align:start position:0% +improper historical document. Let's +stick with Tolken for a + + align:start position:0% + + + + align:start position:0% + +moment. Where I mean where in his + + align:start position:0% +moment. Where I mean where in his + + + align:start position:0% +moment. Where I mean where in his +imaginative world do those kinds of + + align:start position:0% +imaginative world do those kinds of + + + align:start position:0% +imaginative world do those kinds of +Anglo-Saxon narratives fit? + + align:start position:0% +Anglo-Saxon narratives fit? + + + align:start position:0% +Anglo-Saxon narratives fit? +I mean for for men for for men and + + align:start position:0% +I mean for for men for for men and + + + align:start position:0% +I mean for for men for for men and +hobbits it's the same thing. They don't + + align:start position:0% +hobbits it's the same thing. They don't + + + align:start position:0% +hobbits it's the same thing. They don't +know really what happens after they die. + + align:start position:0% +know really what happens after they die. + + + align:start position:0% +know really what happens after they die. +I mean they and in the very same manner + + align:start position:0% +I mean they and in the very same manner + + + align:start position:0% +I mean they and in the very same manner +and and I think that that goes on with + + align:start position:0% +and and I think that that goes on with + + + align:start position:0% +and and I think that that goes on with +in + + align:start position:0% +in + + + align:start position:0% +in +after their, you know, after they didn't + + align:start position:0% +after their, you know, after they didn't + + + align:start position:0% +after their, you know, after they didn't +know what would happen after they + + align:start position:0% +know what would happen after they + + + align:start position:0% +know what would happen after they +defeated Thor, they had no idea what + + align:start position:0% +defeated Thor, they had no idea what + + + align:start position:0% +defeated Thor, they had no idea what +life would be like. And for Froto, what? + + align:start position:0% +life would be like. And for Froto, what? + + + align:start position:0% +life would be like. And for Froto, what? +Well, but what about for Frodo? What's + + align:start position:0% +Well, but what about for Frodo? What's + + + align:start position:0% +Well, but what about for Frodo? What's +different about Froto? + + align:start position:0% +different about Froto? + + + align:start position:0% +different about Froto? +I was going to say another Christian + + align:start position:0% +I was going to say another Christian + + + align:start position:0% +I was going to say another Christian +parallels. He gains the whole world and + + align:start position:0% +parallels. He gains the whole world and + + + align:start position:0% +parallels. He gains the whole world and +then like throws it away. The whole like + + align:start position:0% +then like throws it away. The whole like + + + align:start position:0% +then like throws it away. The whole like +all the power, gives it up for everyone + + align:start position:0% +all the power, gives it up for everyone + + + align:start position:0% +all the power, gives it up for everyone +else. + + align:start position:0% +else. + + + align:start position:0% +else. +Okay. That's not related to what we're + + align:start position:0% +Okay. That's not related to what we're + + + align:start position:0% +Okay. That's not related to what we're +talking about. Okay. But how does it + + align:start position:0% +talking about. Okay. But how does it + + + align:start position:0% +talking about. Okay. But how does it +end? Froto goes into the west. He goes + + align:start position:0% +end? Froto goes into the west. He goes + + + align:start position:0% +end? Froto goes into the west. He goes +into the west. This is where the elves + + align:start position:0% +into the west. This is where the elves + + + align:start position:0% +into the west. This is where the elves +came from. But is it is it really + + align:start position:0% +came from. But is it is it really + + + align:start position:0% +came from. But is it is it really +unknown? No. Is the west really? No, + + align:start position:0% +unknown? No. Is the west really? No, + + + align:start position:0% +unknown? No. Is the west really? No, +it's not unknown at all. But beyond it + + align:start position:0% +it's not unknown at all. But beyond it + + + align:start position:0% +it's not unknown at all. But beyond it +is is the thing because they go there + + align:start position:0% +is is the thing because they go there + + + align:start position:0% +is is the thing because they go there +and then but he's going to die there and + + align:start position:0% +and then but he's going to die there and + + + align:start position:0% +and then but he's going to die there and +then from there he where he goes from + + align:start position:0% +then from there he where he goes from + + + align:start position:0% +then from there he where he goes from +there they have no idea. They go to the + + align:start position:0% +there they have no idea. They go to the + + + align:start position:0% +there they have no idea. They go to the +halls. Well, but then from the halls of + + align:start position:0% +halls. Well, but then from the halls of + + + align:start position:0% +halls. Well, but then from the halls of +Mandos, the the humans and the hobbits + + align:start position:0% +Mandos, the the humans and the hobbits + + + align:start position:0% +Mandos, the the humans and the hobbits +go somewhere. Who's he going with? Who's + + align:start position:0% +go somewhere. Who's he going with? Who's + + + align:start position:0% +go somewhere. Who's he going with? Who's +he going with? Gandalf. + + align:start position:0% +he going with? Gandalf. + + + align:start position:0% +he going with? Gandalf. +The elves. Okay. He's going Yeah. And + + align:start position:0% +The elves. Okay. He's going Yeah. And + + + align:start position:0% +The elves. Okay. He's going Yeah. And +all the other people who are blessed. + + align:start position:0% +all the other people who are blessed. + + + align:start position:0% +all the other people who are blessed. +Okay. He's going with the elves + + align:start position:0% +Okay. He's going with the elves + + + align:start position:0% +Okay. He's going with the elves +to to + + align:start position:0% +to to + + + align:start position:0% +to to +to + + align:start position:0% + + + + align:start position:0% + +what? What's the distinguishing hallmark + + align:start position:0% +what? What's the distinguishing hallmark + + + align:start position:0% +what? What's the distinguishing hallmark +of the elves? The undying limbs. They + + align:start position:0% +of the elves? The undying limbs. They + + + align:start position:0% +of the elves? The undying limbs. They +live forever forever. + + align:start position:0% +live forever forever. + + + align:start position:0% +live forever forever. +Yeah. He won't. That is not totally + + align:start position:0% +Yeah. He won't. That is not totally + + + align:start position:0% +Yeah. He won't. That is not totally +clear. Yeah. Actually, by the undying + + align:start position:0% +clear. Yeah. Actually, by the undying + + + align:start position:0% +clear. Yeah. Actually, by the undying +lens, there is an implication that he's + + align:start position:0% +lens, there is an implication that he's + + + align:start position:0% +lens, there is an implication that he's +not that he the reason he's going is + + align:start position:0% +not that he the reason he's going is + + + align:start position:0% +not that he the reason he's going is +that he doesn't have to die for the + + align:start position:0% +that he doesn't have to die for the + + + align:start position:0% +that he doesn't have to die for the +shadow. That's right. + + align:start position:0% + + + + align:start position:0% + +The first time my sister read it + + align:start position:0% +The first time my sister read it + + + align:start position:0% +The first time my sister read it +actually what she thought she came to me + + align:start position:0% +actually what she thought she came to me + + + align:start position:0% +actually what she thought she came to me +crying at the end of this book and she + + align:start position:0% +crying at the end of this book and she + + + align:start position:0% +crying at the end of this book and she +was in tears. She said, "Anmorry and I I + + align:start position:0% +was in tears. She said, "Anmorry and I I + + + align:start position:0% +was in tears. She said, "Anmorry and I I +hadn't read it." She said, "Any they all + + align:start position:0% +hadn't read it." She said, "Any they all + + + align:start position:0% +hadn't read it." She said, "Any they all +go to commit suicide. + + align:start position:0% + + + + align:start position:0% + +That's what that's what she understood + + align:start position:0% +That's what that's what she understood + + + align:start position:0% +That's what that's what she understood +from going into the boats and going out + + align:start position:0% +from going into the boats and going out + + + align:start position:0% +from going into the boats and going out +into the west to her. They can make the + + align:start position:0% +into the west to her. They can make the + + + align:start position:0% +into the west to her. They can make the +the analogy that it's it's like living + + align:start position:0% +the analogy that it's it's like living + + + align:start position:0% +the analogy that it's it's like living +living closer to the sun that that that + + align:start position:0% +living closer to the sun that that that + + + align:start position:0% +living closer to the sun that that that +you're going to that + + align:start position:0% +you're going to that + + + align:start position:0% +you're going to that +you're you're a candle living closer to + + align:start position:0% +you're you're a candle living closer to + + + align:start position:0% +you're you're a candle living closer to +the to the flame that you burn faster + + align:start position:0% +the to the flame that you burn faster + + + align:start position:0% +the to the flame that you burn faster +that you would even uh die that a mortal + + align:start position:0% +that you would even uh die that a mortal + + + align:start position:0% +that you would even uh die that a mortal +would would even Okay. But but Ian I I'm + + align:start position:0% +would would even Okay. But but Ian I I'm + + + align:start position:0% +would would even Okay. But but Ian I I'm +picking I'm picking at stupid little + + align:start position:0% +picking I'm picking at stupid little + + + align:start position:0% +picking I'm picking at stupid little +things. I don't know. No, no, no, no. + + align:start position:0% +things. I don't know. No, no, no, no. + + + align:start position:0% +things. I don't know. No, no, no, no. +Don't don't ever shut up. Um, just think + + align:start position:0% +Don't don't ever shut up. Um, just think + + + align:start position:0% +Don't don't ever shut up. Um, just think +before you talk, + + align:start position:0% +before you talk, + + + align:start position:0% +before you talk, +um, + + align:start position:0% + + + + align:start position:0% + +if I'm going off admittedly into a kind + + align:start position:0% +if I'm going off admittedly into a kind + + + align:start position:0% +if I'm going off admittedly into a kind +of unknown, but I'm going with a group + + align:start position:0% +of unknown, but I'm going with a group + + + align:start position:0% +of unknown, but I'm going with a group +of people who are totally kind, nice, + + align:start position:0% +of people who are totally kind, nice, + + + align:start position:0% +of people who are totally kind, nice, +gentle, beautiful, right? Gorgeously, + + align:start position:0% +gentle, beautiful, right? Gorgeously, + + + align:start position:0% +gentle, beautiful, right? Gorgeously, +drop deadad beautiful. + + align:start position:0% +drop deadad beautiful. + + + align:start position:0% +drop deadad beautiful. +A lot of them have been there. And and + + align:start position:0% +A lot of them have been there. And and + + + align:start position:0% +A lot of them have been there. And and +they're not going to die. and they all + + align:start position:0% +they're not going to die. and they all + + + align:start position:0% +they're not going to die. and they all +sing beautiful music and play harps and + + align:start position:0% +sing beautiful music and play harps and + + + align:start position:0% +sing beautiful music and play harps and +right and I mean this isn't a scary + + align:start position:0% +right and I mean this isn't a scary + + + align:start position:0% +right and I mean this isn't a scary +prospect. No, I mean it's no scarier for + + align:start position:0% +prospect. No, I mean it's no scarier for + + + align:start position:0% +prospect. No, I mean it's no scarier for +instance than say being a Christian and + + align:start position:0% +instance than say being a Christian and + + + align:start position:0% +instance than say being a Christian and +not quite knowing what heaven is all + + align:start position:0% +not quite knowing what heaven is all + + + align:start position:0% +not quite knowing what heaven is all +about but knowing it's okay because I'm + + align:start position:0% +about but knowing it's okay because I'm + + + align:start position:0% +about but knowing it's okay because I'm +going there and God is there and God is + + align:start position:0% +going there and God is there and God is + + + align:start position:0% +going there and God is there and God is +purely good. So I'm okay. I don't have + + align:start position:0% +purely good. So I'm okay. I don't have + + + align:start position:0% +purely good. So I'm okay. I don't have +to know exactly what's going to happen + + align:start position:0% +to know exactly what's going to happen + + + align:start position:0% +to know exactly what's going to happen +because it's going to be pleasant + + align:start position:0% +because it's going to be pleasant + + + align:start position:0% +because it's going to be pleasant +because I'm in good company and wherever + + align:start position:0% +because I'm in good company and wherever + + + align:start position:0% +because I'm in good company and wherever +they're taking me, I'm gonna be okay. + + align:start position:0% +they're taking me, I'm gonna be okay. + + + align:start position:0% +they're taking me, I'm gonna be okay. +Okay, so let's go back and think again. + + align:start position:0% +Okay, so let's go back and think again. + + + align:start position:0% +Okay, so let's go back and think again. +Beaolf, he dies. He's got the chalice, + + align:start position:0% +Beaolf, he dies. He's got the chalice, + + + align:start position:0% +Beaolf, he dies. He's got the chalice, +you know, or whatever the bit of the + + align:start position:0% +you know, or whatever the bit of the + + + align:start position:0% +you know, or whatever the bit of the +treasure. He's looking on it. He's + + align:start position:0% +treasure. He's looking on it. He's + + + align:start position:0% +treasure. He's looking on it. He's +gazing on it. He's done all the things, + + align:start position:0% +gazing on it. He's done all the things, + + + align:start position:0% +gazing on it. He's done all the things, +right? He can't be accused of murdering + + align:start position:0% +right? He can't be accused of murdering + + + align:start position:0% +right? He can't be accused of murdering +a kinsman. And after all, 90% of these + + align:start position:0% +a kinsman. And after all, 90% of these + + + align:start position:0% +a kinsman. And after all, 90% of these +guys could be. though, right? He's, you + + align:start position:0% +guys could be. though, right? He's, you + + + align:start position:0% +guys could be. though, right? He's, you +know, he's going off with a clean + + align:start position:0% +know, he's going off with a clean + + + align:start position:0% +know, he's going off with a clean +conscience and yet and yet he has no + + align:start position:0% +conscience and yet and yet he has no + + + align:start position:0% +conscience and yet and yet he has no +idea where he's going or what's going to + + align:start position:0% +idea where he's going or what's going to + + + align:start position:0% +idea where he's going or what's going to +happen. Froto doesn't have that ending + + align:start position:0% +happen. Froto doesn't have that ending + + + align:start position:0% +happen. Froto doesn't have that ending +at all. Right. Yeah. Go ahead, Ben. But + + align:start position:0% +at all. Right. Yeah. Go ahead, Ben. But + + + align:start position:0% +at all. Right. Yeah. Go ahead, Ben. But +um you you said something I I haven't + + align:start position:0% +um you you said something I I haven't + + + align:start position:0% +um you you said something I I haven't +read be all the way through parts of it, + + align:start position:0% +read be all the way through parts of it, + + + align:start position:0% +read be all the way through parts of it, +but um you said something about uh the + + align:start position:0% +but um you said something about uh the + + + align:start position:0% +but um you said something about uh the +whailing woman at the end talking about + + align:start position:0% +whailing woman at the end talking about + + + align:start position:0% +whailing woman at the end talking about +how all this stuff can happen now. Isn't + + align:start position:0% +how all this stuff can happen now. Isn't + + + align:start position:0% +how all this stuff can happen now. Isn't +that sort of like how you know like all + + align:start position:0% +that sort of like how you know like all + + + align:start position:0% +that sort of like how you know like all +the heroes are leaving middle or like + + align:start position:0% +the heroes are leaving middle or like + + + align:start position:0% +the heroes are leaving middle or like +the elves are leaving Miller with + + align:start position:0% +the elves are leaving Miller with + + + align:start position:0% +the elves are leaving Miller with +Gandalf you know Frodo and isn't there + + align:start position:0% +Gandalf you know Frodo and isn't there + + + align:start position:0% +Gandalf you know Frodo and isn't there +still that uncertainty? I mean I know + + align:start position:0% +still that uncertainty? I mean I know + + + align:start position:0% +still that uncertainty? I mean I know +the bad guys are dead now but + + align:start position:0% +the bad guys are dead now but + + + align:start position:0% +the bad guys are dead now but +there's always more. Yeah, but there's + + align:start position:0% +there's always more. Yeah, but there's + + + align:start position:0% +there's always more. Yeah, but there's +that uncertainty for like the people + + align:start position:0% +that uncertainty for like the people + + + align:start position:0% +that uncertainty for like the people +that are left. Like you know how the + + align:start position:0% +that are left. Like you know how the + + + align:start position:0% +that are left. Like you know how the +book doesn't end just with them going + + align:start position:0% +book doesn't end just with them going + + + align:start position:0% +book doesn't end just with them going +off. It ends with Sam coming back and + + align:start position:0% +off. It ends with Sam coming back and + + + align:start position:0% +off. It ends with Sam coming back and +saying, "Well, I'm back." Except that + + align:start position:0% +saying, "Well, I'm back." Except that + + + align:start position:0% +saying, "Well, I'm back." Except that +Sam is what? Four-time mayor and he has + + align:start position:0% +Sam is what? Four-time mayor and he has + + + align:start position:0% +Sam is what? Four-time mayor and he has +children, right? You think it's + + align:start position:0% +children, right? You think it's + + + align:start position:0% +children, right? You think it's +unsignificant that Sam is busy getting + + align:start position:0% +unsignificant that Sam is busy getting + + + align:start position:0% +unsignificant that Sam is busy getting +married, having children, having + + align:start position:0% +married, having children, having + + + align:start position:0% +married, having children, having +grandchildren. No, we're supposed to + + align:start position:0% +grandchildren. No, we're supposed to + + + align:start position:0% +grandchildren. No, we're supposed to +feel good about that. I'm not saying + + align:start position:0% +feel good about that. I'm not saying + + + align:start position:0% +feel good about that. I'm not saying +we're we're not, but there's still and + + align:start position:0% +we're we're not, but there's still and + + + align:start position:0% +we're we're not, but there's still and +and Aragon is also he's going to die. + + align:start position:0% +and Aragon is also he's going to die. + + + align:start position:0% +and Aragon is also he's going to die. +Yes. And even Arwin is going to die + + align:start position:0% +Yes. And even Arwin is going to die + + + align:start position:0% +Yes. And even Arwin is going to die +because she's chosen that. But it's + + align:start position:0% +because she's chosen that. But it's + + + align:start position:0% +because she's chosen that. But it's +bittersweet, but it's not + + align:start position:0% +bittersweet, but it's not + + + align:start position:0% +bittersweet, but it's not +tragic. It's bittersweet. Right. And and + + align:start position:0% +tragic. It's bittersweet. Right. And and + + + align:start position:0% +tragic. It's bittersweet. Right. And and +yes, the the age of men that is being + + align:start position:0% +yes, the the age of men that is being + + + align:start position:0% +yes, the the age of men that is being +left behind by wizards and elves, yes, + + align:start position:0% +left behind by wizards and elves, yes, + + + align:start position:0% +left behind by wizards and elves, yes, +they're going to face perils. + + align:start position:0% +they're going to face perils. + + + align:start position:0% +they're going to face perils. +Absolutely, there will be dangers in the + + align:start position:0% +Absolutely, there will be dangers in the + + + align:start position:0% +Absolutely, there will be dangers in the +road ahead, but they are not doomed by + + align:start position:0% +road ahead, but they are not doomed by + + + align:start position:0% +road ahead, but they are not doomed by +any means, right? We can feel at the end + + align:start position:0% +any means, right? We can feel at the end + + + align:start position:0% +any means, right? We can feel at the end +like things are kind of in good hands, + + align:start position:0% +like things are kind of in good hands, + + + align:start position:0% +like things are kind of in good hands, +right? Mary and Pippen are going to live + + align:start position:0% +right? Mary and Pippen are going to live + + + align:start position:0% +right? Mary and Pippen are going to live +to a ripe old age. They're going to + + align:start position:0% +to a ripe old age. They're going to + + + align:start position:0% +to a ripe old age. They're going to +serve their respective feudal overlords + + align:start position:0% +serve their respective feudal overlords + + + align:start position:0% +serve their respective feudal overlords +as knights, basically, right? And the + + align:start position:0% +as knights, basically, right? And the + + + align:start position:0% +as knights, basically, right? And the +age of men will proceed with its ups and + + align:start position:0% +age of men will proceed with its ups and + + + align:start position:0% +age of men will proceed with its ups and +downs, but they're doing the right kinds + + align:start position:0% +downs, but they're doing the right kinds + + + align:start position:0% +downs, but they're doing the right kinds +of things. They're having children, + + align:start position:0% +of things. They're having children, + + + align:start position:0% +of things. They're having children, +right? Bailwolf again has no child. + + align:start position:0% +right? Bailwolf again has no child. + + + align:start position:0% +right? Bailwolf again has no child. +That's what he laments at the end. He's + + align:start position:0% +That's what he laments at the end. He's + + + align:start position:0% +That's what he laments at the end. He's +going into the unknown and he's not even + + align:start position:0% +going into the unknown and he's not even + + + align:start position:0% +going into the unknown and he's not even +leaving someone behind, right? It's a + + align:start position:0% +leaving someone behind, right? It's a + + + align:start position:0% +leaving someone behind, right? It's a +very, very different cast to the ending. + + align:start position:0% +very, very different cast to the ending. + + + align:start position:0% +very, very different cast to the ending. +Even though The Lord of the Rings feels + + align:start position:0% +Even though The Lord of the Rings feels + + + align:start position:0% +Even though The Lord of the Rings feels +kind of antilimatic at the end, I think + + align:start position:0% +kind of antilimatic at the end, I think + + + align:start position:0% +kind of antilimatic at the end, I think +to a lot of readers and obviously to + + align:start position:0% +to a lot of readers and obviously to + + + align:start position:0% +to a lot of readers and obviously to +movie makers. + + align:start position:0% +movie makers. + + + align:start position:0% +movie makers. +Um, but nonetheless, that that is a + + align:start position:0% +Um, but nonetheless, that that is a + + + align:start position:0% +Um, but nonetheless, that that is a +hopeful ending. Whereas the Beaolf + + align:start position:0% +hopeful ending. Whereas the Beaolf + + + align:start position:0% +hopeful ending. Whereas the Beaolf +ending, it is not a hopeful ending at + + align:start position:0% +ending, it is not a hopeful ending at + + + align:start position:0% +ending, it is not a hopeful ending at +all. It's not just that maybe the Swedes + + align:start position:0% +all. It's not just that maybe the Swedes + + + align:start position:0% +all. It's not just that maybe the Swedes +will come. For sure they're coming. + + align:start position:0% +will come. For sure they're coming. + + + align:start position:0% +will come. For sure they're coming. +They're in their boats already, right? + + align:start position:0% +They're in their boats already, right? + + + align:start position:0% +They're in their boats already, right? +They've heard the dragon has killed + + align:start position:0% +They've heard the dragon has killed + + + align:start position:0% +They've heard the dragon has killed +Beaowolf. Oh, excellent. Got rid of that + + align:start position:0% +Beaowolf. Oh, excellent. Got rid of that + + + align:start position:0% +Beaowolf. Oh, excellent. Got rid of that +guy. Um, we can go in now and and reopen + + align:start position:0% +guy. Um, we can go in now and and reopen + + + align:start position:0% +guy. Um, we can go in now and and reopen +that feud that we've had to put on hold + + align:start position:0% +that feud that we've had to put on hold + + + align:start position:0% +that feud that we've had to put on hold +for 50 long years because he was king + + align:start position:0% +for 50 long years because he was king + + + align:start position:0% +for 50 long years because he was king +and so powerful. It's certain that + + align:start position:0% +and so powerful. It's certain that + + + align:start position:0% +and so powerful. It's certain that +they're coming whereas you just don't + + align:start position:0% +they're coming whereas you just don't + + + align:start position:0% +they're coming whereas you just don't +have that kind of despair um at the end. + + align:start position:0% +have that kind of despair um at the end. + + + align:start position:0% +have that kind of despair um at the end. +Yeah. Go ahead, Mono. Before I start + + align:start position:0% +Yeah. Go ahead, Mono. Before I start + + + align:start position:0% +Yeah. Go ahead, Mono. Before I start +making a point, does is there any other + + align:start position:0% +making a point, does is there any other + + + align:start position:0% +making a point, does is there any other +fans of B5 here? Because if there isn't, + + align:start position:0% +fans of B5 here? Because if there isn't, + + + align:start position:0% +fans of B5 here? Because if there isn't, +my point will make no sense. + + align:start position:0% +my point will make no sense. + + + align:start position:0% +my point will make no sense. +B5. I have a friend. I already know. + + align:start position:0% +B5. I have a friend. I already know. + + + align:start position:0% +B5. I have a friend. I already know. +Okay, never mind. I won't make the + + align:start position:0% +Okay, never mind. I won't make the + + + align:start position:0% +Okay, never mind. I won't make the +point. We can move on. Okay. Talking of + + align:start position:0% +point. We can move on. Okay. Talking of + + + align:start position:0% +point. We can move on. Okay. Talking of +endings. Yes. Endings. Um, can we can we + + align:start position:0% +endings. Yes. Endings. Um, can we can we + + + align:start position:0% +endings. Yes. Endings. Um, can we can we +speak a little bit about the ending of + + align:start position:0% +speak a little bit about the ending of + + + align:start position:0% +speak a little bit about the ending of +this book? Absolutely. Where would you + + align:start position:0% +this book? Absolutely. Where would you + + + align:start position:0% +this book? Absolutely. Where would you +like to go? He says, "Are you in the + + align:start position:0% +like to go? He says, "Are you in the + + + align:start position:0% +like to go? He says, "Are you in the +epilogue or the influence?" And the + + align:start position:0% +epilogue or the influence?" And the + + + align:start position:0% +epilogue or the influence?" And the +influence. Page 215. Okay. There you go. + + align:start position:0% +influence. Page 215. Okay. There you go. + + + align:start position:0% +influence. Page 215. Okay. There you go. +Um, two last two sentences. And now in + + align:start position:0% +Um, two last two sentences. And now in + + + align:start position:0% +Um, two last two sentences. And now in +some extreme form of behaviorism, the + + align:start position:0% +some extreme form of behaviorism, the + + + align:start position:0% +some extreme form of behaviorism, the +subject himself is discounted as merely + + align:start position:0% +subject himself is discounted as merely + + + align:start position:0% +subject himself is discounted as merely +subjective. We only think that we think. + + align:start position:0% +subjective. We only think that we think. + + + align:start position:0% +subjective. We only think that we think. +Having eaten up everything else, he eats + + align:start position:0% +Having eaten up everything else, he eats + + + align:start position:0% +Having eaten up everything else, he eats +himself up too. + + align:start position:0% +himself up too. + + + align:start position:0% +himself up too. +I'm very confused. And where we go from + + align:start position:0% +I'm very confused. And where we go from + + + align:start position:0% +I'm very confused. And where we go from +that is a dark question. That's what + + align:start position:0% +that is a dark question. That's what + + + align:start position:0% +that is a dark question. That's what +that's what that's what Caner is + + align:start position:0% +that's what that's what Caner is + + + align:start position:0% +that's what that's what Caner is +rebelling against when he says Lewis is + + align:start position:0% +rebelling against when he says Lewis is + + + align:start position:0% +rebelling against when he says Lewis is +mopey and pessimistic and but really + + align:start position:0% +mopey and pessimistic and but really + + + align:start position:0% +mopey and pessimistic and but really +Caner's just jealous. Doesn't that I + + align:start position:0% +Caner's just jealous. Doesn't that I + + + align:start position:0% +Caner's just jealous. Doesn't that I +mean that really that reflects a lot on + + align:start position:0% +mean that really that reflects a lot on + + + align:start position:0% +mean that really that reflects a lot on +Louiswis's fictional writings. I mean + + align:start position:0% +Louiswis's fictional writings. I mean + + + align:start position:0% +Louiswis's fictional writings. I mean +lying witches the entire Narnia series + + align:start position:0% +lying witches the entire Narnia series + + + align:start position:0% +lying witches the entire Narnia series +has a really really dark overtones that + + align:start position:0% +has a really really dark overtones that + + + align:start position:0% +has a really really dark overtones that +are so nice. No no as says everyone and + + align:start position:0% +are so nice. No no as says everyone and + + + align:start position:0% +are so nice. No no as says everyone and +the end like the last book is really + + align:start position:0% +the end like the last book is really + + + align:start position:0% +the end like the last book is really +dark. It's both really dark orders. + + align:start position:0% +dark. It's both really dark orders. + + + align:start position:0% +dark. It's both really dark orders. +Yeah. It's really both really dark and + + align:start position:0% +Yeah. It's really both really dark and + + + align:start position:0% +Yeah. It's really both really dark and +yet it's also like it's it's the same + + align:start position:0% +yet it's also like it's it's the same + + + align:start position:0% +yet it's also like it's it's the same +sort of feeling of we don't know where + + align:start position:0% +sort of feeling of we don't know where + + + align:start position:0% +sort of feeling of we don't know where +we're going but we think it's going to + + align:start position:0% +we're going but we think it's going to + + + align:start position:0% +we're going but we think it's going to +be better. Like everyone all the good + + align:start position:0% +be better. Like everyone all the good + + + align:start position:0% +be better. Like everyone all the good +people are going there but we're not + + align:start position:0% +people are going there but we're not + + + align:start position:0% +people are going there but we're not +exactly sure where we're going. It's + + align:start position:0% +exactly sure where we're going. It's + + + align:start position:0% +exactly sure where we're going. It's +we're we're destroying something that's + + align:start position:0% +we're we're destroying something that's + + + align:start position:0% +we're we're destroying something that's +really wonderful. Narnia goes away. + + align:start position:0% +really wonderful. Narnia goes away. + + + align:start position:0% +really wonderful. Narnia goes away. +Yeah. but we're going to create sort of + + align:start position:0% +Yeah. but we're going to create sort of + + + align:start position:0% +Yeah. but we're going to create sort of +a new Narnia and the sequestion, but we + + align:start position:0% +a new Narnia and the sequestion, but we + + + align:start position:0% +a new Narnia and the sequestion, but we +don't exactly know for sure if this new + + align:start position:0% +don't exactly know for sure if this new + + + align:start position:0% +don't exactly know for sure if this new +Narnia is going to be that wonderful. + + align:start position:0% +Narnia is going to be that wonderful. + + + align:start position:0% +Narnia is going to be that wonderful. +And so, it's sort of a weird, it's the + + align:start position:0% +And so, it's sort of a weird, it's the + + + align:start position:0% +And so, it's sort of a weird, it's the +same sort of weirdness in the Beaolf + + align:start position:0% +same sort of weirdness in the Beaolf + + + align:start position:0% +same sort of weirdness in the Beaolf +type of feeling that destroying this old + + align:start position:0% +type of feeling that destroying this old + + + align:start position:0% +type of feeling that destroying this old +I mean, one thing has to be said, the + + align:start position:0% +I mean, one thing has to be said, the + + + align:start position:0% +I mean, one thing has to be said, the +seventh book in the Narnia series is by + + align:start position:0% +seventh book in the Narnia series is by + + + align:start position:0% +seventh book in the Narnia series is by +far the most poorly written. And I think + + align:start position:0% +far the most poorly written. And I think + + + align:start position:0% +far the most poorly written. And I think +that's part of the problem. And I'm I'm + + align:start position:0% +that's part of the problem. And I'm I'm + + + align:start position:0% +that's part of the problem. And I'm I'm +I'm I'm willing to uh say that the + + align:start position:0% +I'm I'm willing to uh say that the + + + align:start position:0% +I'm I'm willing to uh say that the +reason what was the title? The last + + align:start position:0% +reason what was the title? The last + + + align:start position:0% +reason what was the title? The last +battle. The last battle. It's by far the + + align:start position:0% +battle. The last battle. It's by far the + + + align:start position:0% +battle. The last battle. It's by far the +most poorly written. I mean, when Caner + + align:start position:0% +most poorly written. I mean, when Caner + + + align:start position:0% +most poorly written. I mean, when Caner +says that the Narnia series is uneven, I + + align:start position:0% +says that the Narnia series is uneven, I + + + align:start position:0% +says that the Narnia series is uneven, I +think that is fair. Um in a way that the + + align:start position:0% +think that is fair. Um in a way that the + + + align:start position:0% +think that is fair. Um in a way that the +Lord of the Rings is, you know, reliable + + align:start position:0% +Lord of the Rings is, you know, reliable + + + align:start position:0% +Lord of the Rings is, you know, reliable +from start to finish. Um, and if you + + align:start position:0% +from start to finish. Um, and if you + + + align:start position:0% +from start to finish. Um, and if you +read the Beaolf and the Critics and the + + align:start position:0% +read the Beaolf and the Critics and the + + + align:start position:0% +read the Beaolf and the Critics and the +Monsters and the Critics, you'll you'll + + align:start position:0% +Monsters and the Critics, you'll you'll + + + align:start position:0% +Monsters and the Critics, you'll you'll +see that same just sort of incredible + + align:start position:0% +see that same just sort of incredible + + + align:start position:0% +see that same just sort of incredible +penetrating um, pen um, at work. You + + align:start position:0% +penetrating um, pen um, at work. You + + + align:start position:0% +penetrating um, pen um, at work. You +know, every sentence is just packed. Um, + + align:start position:0% +know, every sentence is just packed. Um, + + + align:start position:0% +know, every sentence is just packed. Um, +but I want to come back to Ann Marie's + + align:start position:0% +but I want to come back to Ann Marie's + + + align:start position:0% +but I want to come back to Ann Marie's +question. What's going on here? Um, so + + align:start position:0% +question. What's going on here? Um, so + + + align:start position:0% +question. What's going on here? Um, so +let's put it into a context, right? And + + align:start position:0% +let's put it into a context, right? And + + + align:start position:0% +let's put it into a context, right? And +not just jump in at that last paragraph. + + align:start position:0% +not just jump in at that last paragraph. + + + align:start position:0% +not just jump in at that last paragraph. +He has made the argument that we're into + + align:start position:0% +He has made the argument that we're into + + + align:start position:0% +He has made the argument that we're into +originality and that distinguishes us + + align:start position:0% +originality and that distinguishes us + + + align:start position:0% +originality and that distinguishes us +from what came before us. And in fact, + + align:start position:0% +from what came before us. And in fact, + + + align:start position:0% +from what came before us. And in fact, +we're so into originality that we've + + align:start position:0% +we're so into originality that we've + + + align:start position:0% +we're so into originality that we've +gone even like a step beyond that, + + align:start position:0% +gone even like a step beyond that, + + + align:start position:0% +gone even like a step beyond that, +right? And so it's not just that we + + align:start position:0% +right? And so it's not just that we + + + align:start position:0% +right? And so it's not just that we +think we've added something, but maybe + + align:start position:0% +think we've added something, but maybe + + + align:start position:0% +think we've added something, but maybe +we're not even real. We only think we're + + align:start position:0% +we're not even real. We only think we're + + + align:start position:0% +we're not even real. We only think we're +real. Okay? So that as + + align:start position:0% + + + + align:start position:0% + +as in the medieval mind he says nothing + + align:start position:0% +as in the medieval mind he says nothing + + + align:start position:0% +as in the medieval mind he says nothing +is subjective right I don't see the part + + align:start position:0% +is subjective right I don't see the part + + + align:start position:0% +is subjective right I don't see the part +I'm playing in this at + + align:start position:0% +I'm playing in this at + + + align:start position:0% +I'm playing in this at +all then some process of modernization + + align:start position:0% +all then some process of modernization + + + align:start position:0% +all then some process of modernization +happens right we'll pass over that + + align:start position:0% +happens right we'll pass over that + + + align:start position:0% +happens right we'll pass over that +without ex explicating it at all and in + + align:start position:0% +without ex explicating it at all and in + + + align:start position:0% +without ex explicating it at all and in +that process of modernization we become + + align:start position:0% +that process of modernization we become + + + align:start position:0% +that process of modernization we become +more cognizant of what we're + + align:start position:0% +more cognizant of what we're + + + align:start position:0% +more cognizant of what we're +adding but we become so cognizant of + + align:start position:0% +adding but we become so cognizant of + + + align:start position:0% +adding but we become so cognizant of +what we're adding + + align:start position:0% +what we're adding + + + align:start position:0% +what we're adding +that that we can actually become just + + align:start position:0% +that that we can actually become just + + + align:start position:0% +that that we can actually become just +um + + align:start position:0% + + + + align:start position:0% + +uh I think therefore I am is a stage in + + align:start position:0% +uh I think therefore I am is a stage in + + + align:start position:0% +uh I think therefore I am is a stage in +that process right and now + + align:start position:0% +that process right and now + + + align:start position:0% +that process right and now +it's I think I am so maybe I am right + + align:start position:0% +it's I think I am so maybe I am right + + + align:start position:0% +it's I think I am so maybe I am right +but only because I think I am there's + + align:start position:0% +but only because I think I am there's + + + align:start position:0% +but only because I think I am there's +something troubling about that and I + + align:start position:0% +something troubling about that and I + + + align:start position:0% +something troubling about that and I +don't think that Lewis's assessment of + + align:start position:0% +don't think that Lewis's assessment of + + + align:start position:0% +don't think that Lewis's assessment of +things is totally accurate. I think his + + align:start position:0% +things is totally accurate. I think his + + + align:start position:0% +things is totally accurate. I think his +reading of the Middle Ages is more + + align:start position:0% +reading of the Middle Ages is more + + + align:start position:0% +reading of the Middle Ages is more +reliable than his reading of his own + + align:start position:0% +reliable than his reading of his own + + + align:start position:0% +reliable than his reading of his own +times. + + align:start position:0% +times. + + + align:start position:0% +times. +Um, but what he's saying here at the end + + align:start position:0% +Um, but what he's saying here at the end + + + align:start position:0% +Um, but what he's saying here at the end +is if that's + + align:start position:0% +is if that's + + + align:start position:0% +is if that's +true, if that's true, we've eaten up + + align:start position:0% +true, if that's true, we've eaten up + + + align:start position:0% +true, if that's true, we've eaten up +everything else and all we have left is + + align:start position:0% +everything else and all we have left is + + + align:start position:0% +everything else and all we have left is +to eat ourselves, right? And and that is + + align:start position:0% +to eat ourselves, right? And and that is + + + align:start position:0% +to eat ourselves, right? And and that is +his dark question. And I think when + + align:start position:0% +his dark question. And I think when + + + align:start position:0% +his dark question. And I think when +Caner says that Lewis has this kind of + + align:start position:0% +Caner says that Lewis has this kind of + + + align:start position:0% +Caner says that Lewis has this kind of +despair, right, this dark cast to + + align:start position:0% +despair, right, this dark cast to + + + align:start position:0% +despair, right, this dark cast to +things, he's really picking up on the + + align:start position:0% +things, he's really picking up on the + + + align:start position:0% +things, he's really picking up on the +very end of this book. + + align:start position:0% +very end of this book. + + + align:start position:0% +very end of this book. +Um, but I think in general I don't agree + + align:start position:0% +Um, but I think in general I don't agree + + + align:start position:0% +Um, but I think in general I don't agree +with Caner's assessment. Um, there's + + align:start position:0% +with Caner's assessment. Um, there's + + + align:start position:0% +with Caner's assessment. Um, there's +there's one more thing that I that I + + align:start position:0% +there's one more thing that I that I + + + align:start position:0% +there's one more thing that I that I +absolutely want to do because I sent you + + align:start position:0% +absolutely want to do because I sent you + + + align:start position:0% +absolutely want to do because I sent you +these pages and of course I sent them to + + align:start position:0% +these pages and of course I sent them to + + + align:start position:0% +these pages and of course I sent them to +you in such a way that you could not + + align:start position:0% +you in such a way that you could not + + + align:start position:0% +you in such a way that you could not +read them. Um, but but there's but + + align:start position:0% +read them. Um, but but there's but + + + align:start position:0% +read them. Um, but but there's but +there's sort of one more piece to the + + align:start position:0% +there's sort of one more piece to the + + + align:start position:0% +there's sort of one more piece to the +Tolken story that I I want to go back to + + align:start position:0% +Tolken story that I I want to go back to + + + align:start position:0% +Tolken story that I I want to go back to +Broadell. I want to go back to World War + + align:start position:0% +Broadell. I want to go back to World War + + + align:start position:0% +Broadell. I want to go back to World War +II and what all these all these sort of + + align:start position:0% +II and what all these all these sort of + + + align:start position:0% +II and what all these all these sort of +cataclysmic political events that are + + align:start position:0% +cataclysmic political events that are + + + align:start position:0% +cataclysmic political events that are +happening. Okay, Miranda, you're going + + align:start position:0% +happening. Okay, Miranda, you're going + + + align:start position:0% +happening. Okay, Miranda, you're going +to derail me. Yeah. Yeah. I guess if you + + align:start position:0% +to derail me. Yeah. Yeah. I guess if you + + + align:start position:0% +to derail me. Yeah. Yeah. I guess if you +another derailing thing of of one of the + + align:start position:0% +another derailing thing of of one of the + + + align:start position:0% +another derailing thing of of one of the +things I'd always heard against Tolken + + align:start position:0% +things I'd always heard against Tolken + + + align:start position:0% +things I'd always heard against Tolken +is the whole, you know, well, is he + + align:start position:0% +is the whole, you know, well, is he + + + align:start position:0% +is the whole, you know, well, is he +sexist in terms of not having there's + + align:start position:0% +sexist in terms of not having there's + + + align:start position:0% +sexist in terms of not having there's +not a very very strong woman character + + align:start position:0% +not a very very strong woman character + + + align:start position:0% +not a very very strong woman character +or anything like that. But then, you + + align:start position:0% +or anything like that. But then, you + + + align:start position:0% +or anything like that. But then, you +know, you read, well, he had a wonderful + + align:start position:0% +know, you read, well, he had a wonderful + + + align:start position:0% +know, you read, well, he had a wonderful +wife that he loved dearly and children + + align:start position:0% +wife that he loved dearly and children + + + align:start position:0% +wife that he loved dearly and children +and stuff like that. And it's sort of, + + align:start position:0% +and stuff like that. And it's sort of, + + + align:start position:0% +and stuff like that. And it's sort of, +you know, he had four children + + align:start position:0% +you know, he had four children + + + align:start position:0% +you know, he had four children +incidentally, not the three that Caner + + align:start position:0% +incidentally, not the three that Caner + + + align:start position:0% +incidentally, not the three that Caner +says. I'm not sure which one of his + + align:start position:0% +says. I'm not sure which one of his + + + align:start position:0% +says. I'm not sure which one of his +children Caner got rid of, + + align:start position:0% +children Caner got rid of, + + + align:start position:0% +children Caner got rid of, +but it's kind of a serious flaw if + + align:start position:0% +but it's kind of a serious flaw if + + + align:start position:0% +but it's kind of a serious flaw if +you're writing a biography of someone, I + + align:start position:0% +you're writing a biography of someone, I + + + align:start position:0% +you're writing a biography of someone, I +think, to get rid of one of their + + align:start position:0% +think, to get rid of one of their + + + align:start position:0% +think, to get rid of one of their +children, but anyway, that's an aside. + + align:start position:0% +children, but anyway, that's an aside. + + + align:start position:0% +children, but anyway, that's an aside. +But that like I think I'm wondering if + + align:start position:0% +But that like I think I'm wondering if + + + align:start position:0% +But that like I think I'm wondering if +that's a lot more picking up on the + + align:start position:0% +that's a lot more picking up on the + + + align:start position:0% +that's a lot more picking up on the +medieval stuff that there would be you + + align:start position:0% +medieval stuff that there would be you + + + align:start position:0% +medieval stuff that there would be you +know there's women but they're sort of + + align:start position:0% +know there's women but they're sort of + + + align:start position:0% +know there's women but they're sort of +on the side type of they're not really + + align:start position:0% +on the side type of they're not really + + + align:start position:0% +on the side type of they're not really +at all part of like you know nowadays + + align:start position:0% +at all part of like you know nowadays + + + align:start position:0% +at all part of like you know nowadays +you're like well we need to have you + + align:start position:0% +you're like well we need to have you + + + align:start position:0% +you're like well we need to have you +know the woman the you know the guy the + + align:start position:0% +know the woman the you know the guy the + + + align:start position:0% +know the woman the you know the guy the +Yeah. Okay. There's a huge literature on + + align:start position:0% +Yeah. Okay. There's a huge literature on + + + align:start position:0% +Yeah. Okay. There's a huge literature on +this and we won't we won't go there + + align:start position:0% +this and we won't we won't go there + + + align:start position:0% +this and we won't we won't go there +because I actually have somewhere else I + + align:start position:0% +because I actually have somewhere else I + + + align:start position:0% +because I actually have somewhere else I +want to go and we don't have enough time + + align:start position:0% +want to go and we don't have enough time + + + align:start position:0% +want to go and we don't have enough time +to do both. Um, but let me just say + + align:start position:0% +to do both. Um, but let me just say + + + align:start position:0% +to do both. Um, but let me just say +this. Uh, Tolken's world is utterly a + + align:start position:0% +this. Uh, Tolken's world is utterly a + + + align:start position:0% +this. Uh, Tolken's world is utterly a +masculinist one. It is also a violent + + align:start position:0% +masculinist one. It is also a violent + + + align:start position:0% +masculinist one. It is also a violent +one. It is perfectly possible to write a + + align:start position:0% +one. It is perfectly possible to write a + + + align:start position:0% +one. It is perfectly possible to write a +good feminist critique of all of this + + align:start position:0% +good feminist critique of all of this + + + align:start position:0% +good feminist critique of all of this +and + + align:start position:0% +and + + + align:start position:0% +and +say, "Look at that masculinist world and + + align:start position:0% +say, "Look at that masculinist world and + + + align:start position:0% +say, "Look at that masculinist world and +how violent it is." Um, right. Tolken, + + align:start position:0% +how violent it is." Um, right. Tolken, + + + align:start position:0% +how violent it is." Um, right. Tolken, +if pressed on this, would say, "You're + + align:start position:0% +if pressed on this, would say, "You're + + + align:start position:0% +if pressed on this, would say, "You're +right. Absolutely. It's a violent world. + + align:start position:0% +right. Absolutely. It's a violent world. + + + align:start position:0% +right. Absolutely. It's a violent world. +That is the world that I know. This is + + align:start position:0% +That is the world that I know. This is + + + align:start position:0% +That is the world that I know. This is +in fact the world of sin, right? This is + + align:start position:0% +in fact the world of sin, right? This is + + + align:start position:0% +in fact the world of sin, right? This is +the fallen world. It is violent. And to + + align:start position:0% +the fallen world. It is violent. And to + + + align:start position:0% +the fallen world. It is violent. And to +the extent that we can mitigate that + + align:start position:0% + + + + align:start position:0% + +violence in whatever way, but maybe also + + align:start position:0% +violence in whatever way, but maybe also + + + align:start position:0% +violence in whatever way, but maybe also +in the way of of um female influence, + + align:start position:0% +in the way of of um female influence, + + + align:start position:0% +in the way of of um female influence, +that's a good thing. Now, if you've got + + align:start position:0% +that's a good thing. Now, if you've got + + + align:start position:0% +that's a good thing. Now, if you've got +sort of Beaolf running in your head from + + align:start position:0% +sort of Beaolf running in your head from + + + align:start position:0% +sort of Beaolf running in your head from +start to finish, you know that in that + + align:start position:0% +start to finish, you know that in that + + + align:start position:0% +start to finish, you know that in that +Anglo-Saxon world, female peacemaking + + align:start position:0% +Anglo-Saxon world, female peacemaking + + + align:start position:0% +Anglo-Saxon world, female peacemaking +doesn't work. We have at least three + + align:start position:0% +doesn't work. We have at least three + + + align:start position:0% +doesn't work. We have at least three +separate episodes in the Beaowolf larger + + align:start position:0% +separate episodes in the Beaowolf larger + + + align:start position:0% +separate episodes in the Beaowolf larger +narrative of specific references to + + align:start position:0% +narrative of specific references to + + + align:start position:0% +narrative of specific references to +attempts to use women. In fact, they're + + align:start position:0% +attempts to use women. In fact, they're + + + align:start position:0% +attempts to use women. In fact, they're +called like the queen, the Danish queen + + align:start position:0% +called like the queen, the Danish queen + + + align:start position:0% +called like the queen, the Danish queen +is called a peace weaver. Three or four + + align:start position:0% +is called a peace weaver. Three or four + + + align:start position:0% +is called a peace weaver. Three or four +times she's called that, a peacewaver. + + align:start position:0% +times she's called that, a peacewaver. + + + align:start position:0% +times she's called that, a peacewaver. +And yet we know it doesn't work because + + align:start position:0% +And yet we know it doesn't work because + + + align:start position:0% +And yet we know it doesn't work because +they're constantly feuding with each + + align:start position:0% +they're constantly feuding with each + + + align:start position:0% +they're constantly feuding with each +other. The lay of Ingeld which is + + align:start position:0% +other. The lay of Ingeld which is + + + align:start position:0% +other. The lay of Ingeld which is +embedded in there. Ingeld is married off + + align:start position:0% +embedded in there. Ingeld is married off + + + align:start position:0% +embedded in there. Ingeld is married off +to a woman who is the daughter of his + + align:start position:0% +to a woman who is the daughter of his + + + align:start position:0% +to a woman who is the daughter of his +enemy. And the idea is it's supposed to + + align:start position:0% +enemy. And the idea is it's supposed to + + + align:start position:0% +enemy. And the idea is it's supposed to +make peace. What does it do? Well, in + + align:start position:0% +make peace. What does it do? Well, in + + + align:start position:0% +make peace. What does it do? Well, in +fact, he ends up in the completely + + align:start position:0% +fact, he ends up in the completely + + + align:start position:0% +fact, he ends up in the completely +intractable situation of trying to + + align:start position:0% +intractable situation of trying to + + + align:start position:0% +intractable situation of trying to +decide whether he should kill his wife's + + align:start position:0% +decide whether he should kill his wife's + + + align:start position:0% +decide whether he should kill his wife's +father or his own brother, right? And + + align:start position:0% +father or his own brother, right? And + + + align:start position:0% +father or his own brother, right? And +you know, great, you lose both ways. So + + align:start position:0% +you know, great, you lose both ways. So + + + align:start position:0% +you know, great, you lose both ways. So +Tolken would acknowledge, I think, + + align:start position:0% +Tolken would acknowledge, I think, + + + align:start position:0% +Tolken would acknowledge, I think, +freely that his world is a totally + + align:start position:0% +freely that his world is a totally + + + align:start position:0% +freely that his world is a totally +masculineist one and that it's violent, + + align:start position:0% +masculineist one and that it's violent, + + + align:start position:0% +masculineist one and that it's violent, +but he would also say, "Look, read the + + align:start position:0% +but he would also say, "Look, read the + + + align:start position:0% +but he would also say, "Look, read the +sources. Read Beaolf. It'll tell you + + align:start position:0% +sources. Read Beaolf. It'll tell you + + + align:start position:0% +sources. Read Beaolf. It'll tell you +women aren't going to solve this + + align:start position:0% +women aren't going to solve this + + + align:start position:0% +women aren't going to solve this +problem." Okay? So I'm going to leave it + + align:start position:0% +problem." Okay? So I'm going to leave it + + + align:start position:0% +problem." Okay? So I'm going to leave it +at that. Okay? But I want I want to go + + align:start position:0% +at that. Okay? But I want I want to go + + + align:start position:0% +at that. Okay? But I want I want to go +back to war. + + align:start position:0% +back to war. + + + align:start position:0% +back to war. +Um, as you know, uh, Beaolf is a, um, + + align:start position:0% +Um, as you know, uh, Beaolf is a, um, + + + align:start position:0% +Um, as you know, uh, Beaolf is a, um, +uh, sort of a not about an Anglo-Saxon, + + align:start position:0% +uh, sort of a not about an Anglo-Saxon, + + + align:start position:0% +uh, sort of a not about an Anglo-Saxon, +but + + align:start position:0% +but + + + align:start position:0% +but +nonetheless speaks to, um, Anglo-Saxon + + align:start position:0% +nonetheless speaks to, um, Anglo-Saxon + + + align:start position:0% +nonetheless speaks to, um, Anglo-Saxon +culture. It is, after all, written by an + + align:start position:0% +culture. It is, after all, written by an + + + align:start position:0% +culture. It is, after all, written by an +Anglo-Saxon in the Anglo-Saxon language. + + align:start position:0% +Anglo-Saxon in the Anglo-Saxon language. + + + align:start position:0% +Anglo-Saxon in the Anglo-Saxon language. +Uh, and and Tolken specifically + + align:start position:0% +Uh, and and Tolken specifically + + + align:start position:0% +Uh, and and Tolken specifically +responded on numerous occasions to + + align:start position:0% +responded on numerous occasions to + + + align:start position:0% +responded on numerous occasions to +critics who poo pooed it. You may know + + align:start position:0% +critics who poo pooed it. You may know + + + align:start position:0% +critics who poo pooed it. You may know +that it was considered to be a totally + + align:start position:0% +that it was considered to be a totally + + + align:start position:0% +that it was considered to be a totally +inferior text for a long time basically + + align:start position:0% +inferior text for a long time basically + + + align:start position:0% +inferior text for a long time basically +because it had been written by some beer + + align:start position:0% +because it had been written by some beer + + + align:start position:0% +because it had been written by some beer +swilling + + align:start position:0% +swilling + + + align:start position:0% +swilling +Anglo-Saxon. Uh so this is this is this + + align:start position:0% +Anglo-Saxon. Uh so this is this is this + + + align:start position:0% +Anglo-Saxon. Uh so this is this is this +is um Tolken's response to this. This is + + align:start position:0% +is um Tolken's response to this. This is + + + align:start position:0% +is um Tolken's response to this. This is +from um um I actually let me let me read + + align:start position:0% +from um um I actually let me let me read + + + align:start position:0% +from um um I actually let me let me read +his actual response from from the the + + align:start position:0% +his actual response from from the the + + + align:start position:0% +his actual response from from the the +the essay Beaolf and the Critics and + + align:start position:0% +the essay Beaolf and the Critics and + + + align:start position:0% +the essay Beaolf and the Critics and +then I'm going to read you some some + + align:start position:0% +then I'm going to read you some some + + + align:start position:0% +then I'm going to read you some some +letters. All right. + + align:start position:0% +letters. All right. + + + align:start position:0% +letters. All right. +He's talking about a French critic, + + align:start position:0% +He's talking about a French critic, + + + align:start position:0% +He's talking about a French critic, +Yuserand. The strange poem of Beaowolf. + + align:start position:0% +Yuserand. The strange poem of Beaowolf. + + + align:start position:0% +Yuserand. The strange poem of Beaowolf. +He wanders on the most important + + align:start position:0% +He wanders on the most important + + + align:start position:0% +He wanders on the most important +monument of Anglo-Saxon literature and + + align:start position:0% +monument of Anglo-Saxon literature and + + + align:start position:0% +monument of Anglo-Saxon literature and +then in parenthesis talking has the poor + + align:start position:0% +then in parenthesis talking has the poor + + + align:start position:0% +then in parenthesis talking has the poor +poet lifts his nose out of his beerhorn + + align:start position:0% +poet lifts his nose out of his beerhorn + + + align:start position:0% +poet lifts his nose out of his beerhorn +and humbly acknowledges the gentleman's + + align:start position:0% +and humbly acknowledges the gentleman's + + + align:start position:0% +and humbly acknowledges the gentleman's +condescension. Like old Celtic tales is + + align:start position:0% +condescension. Like old Celtic tales is + + + align:start position:0% +condescension. Like old Celtic tales is +a medly of pagan legends which do not + + align:start position:0% +a medly of pagan legends which do not + + + align:start position:0% +a medly of pagan legends which do not +concern Beaolf the hero in particular + + align:start position:0% +concern Beaolf the hero in particular + + + align:start position:0% +concern Beaolf the hero in particular +and of historical facts. New discrepancy + + align:start position:0% +and of historical facts. New discrepancy + + + align:start position:0% +and of historical facts. New discrepancy +is introduced in trying to adapt the old + + align:start position:0% +is introduced in trying to adapt the old + + + align:start position:0% +is introduced in trying to adapt the old +tale to the faith of his the author's + + align:start position:0% +tale to the faith of his the author's + + + align:start position:0% +tale to the faith of his the author's +day. No need to expedate on the + + align:start position:0% +day. No need to expedate on the + + + align:start position:0% +day. No need to expedate on the +incoherence of a poem formed of such + + align:start position:0% +incoherence of a poem formed of such + + + align:start position:0% +incoherence of a poem formed of such +elements. Then in parenthesis, Tolken + + align:start position:0% +elements. Then in parenthesis, Tolken + + + align:start position:0% +elements. Then in parenthesis, Tolken +says, "The poor poet here hastily hides + + align:start position:0% +says, "The poor poet here hastily hides + + + align:start position:0% +says, "The poor poet here hastily hides +his blushes in the beer horn again. Its + + align:start position:0% +his blushes in the beer horn again. Its + + + align:start position:0% +his blushes in the beer horn again. Its +heroes, now we're back to the French + + align:start position:0% +heroes, now we're back to the French + + + align:start position:0% +heroes, now we're back to the French +critic, its heroes are at once pagan and + + align:start position:0% +critic, its heroes are at once pagan and + + + align:start position:0% +critic, its heroes are at once pagan and +Christian. They believe in Christ and we + + align:start position:0% +Christian. They believe in Christ and we + + + align:start position:0% +Christian. They believe in Christ and we +deathly and complicated flabbergasted + + align:start position:0% +deathly and complicated flabbergasted + + + align:start position:0% +deathly and complicated flabbergasted +silence throughout the hall while a + + align:start position:0% +silence throughout the hall while a + + + align:start position:0% +silence throughout the hall while a +horrible suspicion crosses the poet's + + align:start position:0% +horrible suspicion crosses the poet's + + + align:start position:0% +horrible suspicion crosses the poet's +mind that the magnificent gentleman is + + align:start position:0% +mind that the magnificent gentleman is + + + align:start position:0% +mind that the magnificent gentleman is +an + + align:start position:0% +an + + + align:start position:0% +an +idiot." Anyway, this whole essay is like + + align:start position:0% +idiot." Anyway, this whole essay is like + + + align:start position:0% +idiot." Anyway, this whole essay is like +this. you know, 70 pages of this kind of + + align:start position:0% +this. you know, 70 pages of this kind of + + + align:start position:0% +this. you know, 70 pages of this kind of +sort of very biting criticism, but the + + align:start position:0% +sort of very biting criticism, but the + + + align:start position:0% +sort of very biting criticism, but the +the racial issues that are implied in + + align:start position:0% +the racial issues that are implied in + + + align:start position:0% +the racial issues that are implied in +all of this, what it means to be + + align:start position:0% +all of this, what it means to be + + + align:start position:0% +all of this, what it means to be +Germanic, Tutonic, Norse, heroic, right, + + align:start position:0% +Germanic, Tutonic, Norse, heroic, right, + + + align:start position:0% +Germanic, Tutonic, Norse, heroic, right, +are fraught ones in the context of World + + align:start position:0% +are fraught ones in the context of World + + + align:start position:0% +are fraught ones in the context of World +War I and World War II, obviously, + + align:start position:0% +War I and World War II, obviously, + + + align:start position:0% +War I and World War II, obviously, +right? What does it mean to have a + + align:start position:0% +right? What does it mean to have a + + + align:start position:0% +right? What does it mean to have a +Germanic hero that kills dragons and + + align:start position:0% +Germanic hero that kills dragons and + + + align:start position:0% +Germanic hero that kills dragons and +goes to the bottom of the sea, right? + + align:start position:0% +goes to the bottom of the sea, right? + + + align:start position:0% +goes to the bottom of the sea, right? +especially if you're an Englishman + + align:start position:0% +especially if you're an Englishman + + + align:start position:0% +especially if you're an Englishman +writing about a monument of your English + + align:start position:0% +writing about a monument of your English + + + align:start position:0% +writing about a monument of your English +past, an Anglo-Saxon poem. Uh this is + + align:start position:0% +past, an Anglo-Saxon poem. Uh this is + + + align:start position:0% +past, an Anglo-Saxon poem. Uh this is +from a letter uh written in + + align:start position:0% +from a letter uh written in + + + align:start position:0% +from a letter uh written in +1941 to his son Michael. I have spent + + align:start position:0% +1941 to his son Michael. I have spent + + + align:start position:0% +1941 to his son Michael. I have spent +most of my life since I was your age + + align:start position:0% +most of my life since I was your age + + + align:start position:0% +most of my life since I was your age +studying Germanic matters in the general + + align:start position:0% +studying Germanic matters in the general + + + align:start position:0% +studying Germanic matters in the general +sense that includes England and + + align:start position:0% +sense that includes England and + + + align:start position:0% +sense that includes England and +Scandinavia. There is a great deal more + + align:start position:0% +Scandinavia. There is a great deal more + + + align:start position:0% +Scandinavia. There is a great deal more +force and truth than ignorant people + + align:start position:0% +force and truth than ignorant people + + + align:start position:0% +force and truth than ignorant people +imagine in the Germanic ideal. I was + + align:start position:0% +imagine in the Germanic ideal. I was + + + align:start position:0% +imagine in the Germanic ideal. I was +much attracted by it as an undergraduate + + align:start position:0% +much attracted by it as an undergraduate + + + align:start position:0% +much attracted by it as an undergraduate +when Hitler was, I suppose, dabbling in + + align:start position:0% +when Hitler was, I suppose, dabbling in + + + align:start position:0% +when Hitler was, I suppose, dabbling in +paint and had not heard of it in + + align:start position:0% +paint and had not heard of it in + + + align:start position:0% +paint and had not heard of it in +reaction against the classics, but no + + align:start position:0% +reaction against the classics, but no + + + align:start position:0% +reaction against the classics, but no +one ever calls on me to broadcast or to + + align:start position:0% +one ever calls on me to broadcast or to + + + align:start position:0% +one ever calls on me to broadcast or to +do a postcript. Yet, I suppose I know + + align:start position:0% +do a postcript. Yet, I suppose I know + + + align:start position:0% +do a postcript. Yet, I suppose I know +better than most what is the truth about + + align:start position:0% +better than most what is the truth about + + + align:start position:0% +better than most what is the truth about +this Nordic nonsense. Anyway, I have in + + align:start position:0% +this Nordic nonsense. Anyway, I have in + + + align:start position:0% +this Nordic nonsense. Anyway, I have in +this war, that would be World War II + + align:start position:0% +this war, that would be World War II + + + align:start position:0% +this war, that would be World War II +now, a burning private grudge which + + align:start position:0% +now, a burning private grudge which + + + align:start position:0% +now, a burning private grudge which +would probably make me a better soldier + + align:start position:0% +would probably make me a better soldier + + + align:start position:0% +would probably make me a better soldier +at 49 than I was at 22 against that + + align:start position:0% +at 49 than I was at 22 against that + + + align:start position:0% +at 49 than I was at 22 against that +ruddy little ignoramis Adolf Hitler. + + align:start position:0% +ruddy little ignoramis Adolf Hitler. + + + align:start position:0% +ruddy little ignoramis Adolf Hitler. +Ruining, perverting, misapplying, and + + align:start position:0% +Ruining, perverting, misapplying, and + + + align:start position:0% +Ruining, perverting, misapplying, and +making forever a cursed that noble + + align:start position:0% +making forever a cursed that noble + + + align:start position:0% +making forever a cursed that noble +northern spirit a supreme contribution + + align:start position:0% +northern spirit a supreme contribution + + + align:start position:0% +northern spirit a supreme contribution +to Europe which I have ever loved and + + align:start position:0% +to Europe which I have ever loved and + + + align:start position:0% +to Europe which I have ever loved and +tried to present in its true light. + + align:start position:0% +tried to present in its true light. + + + align:start position:0% +tried to present in its true light. +Nowhere, incidentally, was it nobler + + align:start position:0% +Nowhere, incidentally, was it nobler + + + align:start position:0% +Nowhere, incidentally, was it nobler +than in England, nor more early + + align:start position:0% +than in England, nor more early + + + align:start position:0% +than in England, nor more early +sanctified and Christianized. And this + + align:start position:0% +sanctified and Christianized. And this + + + align:start position:0% +sanctified and Christianized. And this +is a really powerful + + align:start position:0% +is a really powerful + + + align:start position:0% +is a really powerful +passage because Tolken with his German + + align:start position:0% +passage because Tolken with his German + + + align:start position:0% +passage because Tolken with his German +name, right, and his love of German + + align:start position:0% +name, right, and his love of German + + + align:start position:0% +name, right, and his love of German +Germanic lore and these heroes and this + + align:start position:0% +Germanic lore and these heroes and this + + + align:start position:0% +Germanic lore and these heroes and this +masculinist culture, right, which he + + align:start position:0% +masculinist culture, right, which he + + + align:start position:0% +masculinist culture, right, which he +freely partates + + align:start position:0% +freely partates + + + align:start position:0% +freely partates +in is feeling the tension of being alive + + align:start position:0% +in is feeling the tension of being alive + + + align:start position:0% +in is feeling the tension of being alive +in + + align:start position:0% +in + + + align:start position:0% +in +1941 and looking at what someone is + + align:start position:0% +1941 and looking at what someone is + + + align:start position:0% +1941 and looking at what someone is +doing with a quote Germanic ideal. + + align:start position:0% +doing with a quote Germanic ideal. + + + align:start position:0% +doing with a quote Germanic ideal. +Let me read one more from one more + + align:start position:0% +Let me read one more from one more + + + align:start position:0% +Let me read one more from one more +letter. This actually is dated in 1938. + + align:start position:0% +letter. This actually is dated in 1938. + + + align:start position:0% +letter. This actually is dated in 1938. +So before the Sudatan land, right back + + align:start position:0% +So before the Sudatan land, right back + + + align:start position:0% +So before the Sudatan land, right back +at a moment when people were still + + align:start position:0% +at a moment when people were still + + + align:start position:0% +at a moment when people were still +saying, "Hey, maybe we don't really know + + align:start position:0% +saying, "Hey, maybe we don't really know + + + align:start position:0% +saying, "Hey, maybe we don't really know +what's happening in Germany." I think + + align:start position:0% +what's happening in Germany." I think + + + align:start position:0% +what's happening in Germany." I think +it's very telling. Um this is a letter + + align:start position:0% +it's very telling. Um this is a letter + + + align:start position:0% +it's very telling. Um this is a letter +that was written to a German publishing + + align:start position:0% +that was written to a German publishing + + + align:start position:0% +that was written to a German publishing +house louning fell who were negotiating + + align:start position:0% +house louning fell who were negotiating + + + align:start position:0% +house louning fell who were negotiating +a publication of a German translation of + + align:start position:0% +a publication of a German translation of + + + align:start position:0% +a publication of a German translation of +the hobbit and they asked Tolken if he + + align:start position:0% +the hobbit and they asked Tolken if he + + + align:start position:0% +the hobbit and they asked Tolken if he +was Irish that is are you + + align:start position:0% +was Irish that is are you + + + align:start position:0% +was Irish that is are you +Aryan? He + + align:start position:0% +Aryan? He + + + align:start position:0% +Aryan? He +replied he was not aware sorry I am not + + align:start position:0% +replied he was not aware sorry I am not + + + align:start position:0% +replied he was not aware sorry I am not +aware that any of my ancestors spoke + + align:start position:0% +aware that any of my ancestors spoke + + + align:start position:0% +aware that any of my ancestors spoke +Hindustani Persian Gypsy or any related + + align:start position:0% +Hindustani Persian Gypsy or any related + + + align:start position:0% +Hindustani Persian Gypsy or any related +dialects and therefore cannot claim to + + align:start position:0% +dialects and therefore cannot claim to + + + align:start position:0% +dialects and therefore cannot claim to +be Aryan. However, if I am to understand + + align:start position:0% +be Aryan. However, if I am to understand + + + align:start position:0% +be Aryan. However, if I am to understand +that you are inquiring whether I am of + + align:start position:0% +that you are inquiring whether I am of + + + align:start position:0% +that you are inquiring whether I am of +Jewish origin, I can only reply that I + + align:start position:0% +Jewish origin, I can only reply that I + + + align:start position:0% +Jewish origin, I can only reply that I +regret that I appear to have no + + align:start position:0% +regret that I appear to have no + + + align:start position:0% +regret that I appear to have no +ancestors of that gifted people. The + + align:start position:0% +ancestors of that gifted people. The + + + align:start position:0% +ancestors of that gifted people. The +letter goes on for a space and then it + + align:start position:0% +letter goes on for a space and then it + + + align:start position:0% +letter goes on for a space and then it +ends like this. I have been accustomed + + align:start position:0% +ends like this. I have been accustomed + + + align:start position:0% +ends like this. I have been accustomed +to regard my German name with pride and + + align:start position:0% +to regard my German name with pride and + + + align:start position:0% +to regard my German name with pride and +continued to do so throughout the period + + align:start position:0% +continued to do so throughout the period + + + align:start position:0% +continued to do so throughout the period +of the late regrettable war. That would + + align:start position:0% +of the late regrettable war. That would + + + align:start position:0% +of the late regrettable war. That would +be World War I. I cannot, however, + + align:start position:0% +be World War I. I cannot, however, + + + align:start position:0% +be World War I. I cannot, however, +forebear to comment that if impertinent + + align:start position:0% +forebear to comment that if impertinent + + + align:start position:0% +forebear to comment that if impertinent +and irrelevant inquiries of this sort + + align:start position:0% +and irrelevant inquiries of this sort + + + align:start position:0% +and irrelevant inquiries of this sort +are to become the rule in matters of + + align:start position:0% +are to become the rule in matters of + + + align:start position:0% +are to become the rule in matters of +literature, then the time is not far + + align:start position:0% +literature, then the time is not far + + + align:start position:0% +literature, then the time is not far +distant when a German name will no + + align:start position:0% +distant when a German name will no + + + align:start position:0% +distant when a German name will no +longer be a source of pride. + + align:start position:0% +longer be a source of pride. + + + align:start position:0% +longer be a source of pride. +I just wanted you to have that because I + + align:start position:0% +I just wanted you to have that because I + + + align:start position:0% +I just wanted you to have that because I +mean such a powerful + + align:start position:0% +mean such a powerful + + + align:start position:0% +mean such a powerful +testimony to understanding + + align:start position:0% +testimony to understanding + + + align:start position:0% +testimony to understanding +um particularly particularly the letter + + align:start position:0% +um particularly particularly the letter + + + align:start position:0% +um particularly particularly the letter +written in + + align:start position:0% +written in + + + align:start position:0% +written in +1938 when + + align:start position:0% +1938 when + + + align:start position:0% +1938 when +um you know when lots of reasonable + + align:start position:0% +um you know when lots of reasonable + + + align:start position:0% +um you know when lots of reasonable +people said gosh we had no idea what was + + align:start position:0% +people said gosh we had no idea what was + + + align:start position:0% +people said gosh we had no idea what was +coming. Um how could we possibly have + + align:start position:0% +coming. Um how could we possibly have + + + align:start position:0% +coming. Um how could we possibly have +known right? Right. I mean, clearly + + align:start position:0% +known right? Right. I mean, clearly + + + align:start position:0% +known right? Right. I mean, clearly +Tolken has a pretty good sense um of + + align:start position:0% +Tolken has a pretty good sense um of + + + align:start position:0% +Tolken has a pretty good sense um of +what's happening, but I mean, I also + + align:start position:0% +what's happening, but I mean, I also + + + align:start position:0% +what's happening, but I mean, I also +wanted you to have that because it is + + align:start position:0% +wanted you to have that because it is + + + align:start position:0% +wanted you to have that because it is +easy to + + align:start position:0% + + + + align:start position:0% + +um it is easy to to um + + align:start position:0% +um it is easy to to um + + + align:start position:0% +um it is easy to to um +ridicule, right, the that Germanic + + align:start position:0% +ridicule, right, the that Germanic + + + align:start position:0% +ridicule, right, the that Germanic +ideal, which clearly I mean, which + + align:start position:0% +ideal, which clearly I mean, which + + + align:start position:0% +ideal, which clearly I mean, which +clearly he lived, breathed, died, right, + + align:start position:0% +clearly he lived, breathed, died, right, + + + align:start position:0% +clearly he lived, breathed, died, right, +and it informs his fiction + + align:start position:0% +and it informs his fiction + + + align:start position:0% +and it informs his fiction +utterly. + + align:start position:0% +utterly. + + + align:start position:0% +utterly. +Um, and given the context in which it + + align:start position:0% +Um, and given the context in which it + + + align:start position:0% +Um, and given the context in which it +was written could easily be + + align:start position:0% +was written could easily be + + + align:start position:0% +was written could easily be +misunderstood. And I and I and and I + + align:start position:0% +misunderstood. And I and I and and I + + + align:start position:0% +misunderstood. And I and I and and I +wanted to close with that because it + + align:start position:0% +wanted to close with that because it + + + align:start position:0% +wanted to close with that because it +takes us back one more time to Broadell, + + align:start position:0% +takes us back one more time to Broadell, + + + align:start position:0% +takes us back one more time to Broadell, +right, who also saw, if you will, the + + align:start position:0% +right, who also saw, if you will, the + + + align:start position:0% +right, who also saw, if you will, the +horrors of a particular way of thinking + + align:start position:0% +horrors of a particular way of thinking + + + align:start position:0% +horrors of a particular way of thinking +about + + align:start position:0% +about + + + align:start position:0% +about +race + + align:start position:0% +race + + + align:start position:0% +race +and and and he faces race. I mean, after + + align:start position:0% +and and and he faces race. I mean, after + + + align:start position:0% +and and and he faces race. I mean, after +all, Tolkien is celebrating race in many + + align:start position:0% +all, Tolkien is celebrating race in many + + + align:start position:0% +all, Tolkien is celebrating race in many +ways. + + align:start position:0% +ways. + + + align:start position:0% +ways. +Broadell is he facing it by saying you + + align:start position:0% +Broadell is he facing it by saying you + + + align:start position:0% +Broadell is he facing it by saying you +know no no what really matters is the + + align:start position:0% +know no no what really matters is the + + + align:start position:0% +know no no what really matters is the +mountains the air right the earth the + + align:start position:0% +mountains the air right the earth the + + + align:start position:0% +mountains the air right the earth the +camels right all these other things it's + + align:start position:0% +camels right all these other things it's + + + align:start position:0% +camels right all these other things it's +not race uh but both of them you can see + + align:start position:0% +not race uh but both of them you can see + + + align:start position:0% +not race uh but both of them you can see +I mean these are these are these are + + align:start position:0% +I mean these are these are these are + + + align:start position:0% +I mean these are these are these are +very intelligent men struggling with a + + align:start position:0% +very intelligent men struggling with a + + + align:start position:0% +very intelligent men struggling with a +world that is somewhat incomprehensible + + align:start position:0% +world that is somewhat incomprehensible + + + align:start position:0% +world that is somewhat incomprehensible +to them because it's gone mad right in + + align:start position:0% +to them because it's gone mad right in + + + align:start position:0% +to them because it's gone mad right in +some very real sense from the way they + + align:start position:0% +some very real sense from the way they + + + align:start position:0% +some very real sense from the way they +think about things and and what they + + align:start position:0% +think about things and and what they + + + align:start position:0% +think about things and and what they +write in Tolken it's fiction in broadell + + align:start position:0% +write in Tolken it's fiction in broadell + + + align:start position:0% +write in Tolken it's fiction in broadell +it's history but that line is a fine one + + align:start position:0% +it's history but that line is a fine one + + + align:start position:0% +it's history but that line is a fine one +as we've already said what they write + + align:start position:0% +as we've already said what they write + + + align:start position:0% +as we've already said what they write +then has to somehow deal with this + + align:start position:0% +then has to somehow deal with this + + + align:start position:0% +then has to somehow deal with this +problem that they're confronted with + + align:start position:0% +problem that they're confronted with + + + align:start position:0% +problem that they're confronted with +which is that they live in this world + + align:start position:0% +which is that they live in this world + + + align:start position:0% +which is that they live in this world +gone mad in particular over this + + align:start position:0% +gone mad in particular over this + + + align:start position:0% +gone mad in particular over this +question of race + + align:start position:0% +question of race + + + align:start position:0% +question of race +um and I just I wanted to close with + + align:start position:0% +um and I just I wanted to close with + + + align:start position:0% +um and I just I wanted to close with +that because I mean one uh you know + + align:start position:0% +that because I mean one uh you know + + + align:start position:0% +that because I mean one uh you know +clearly Tolken was a mench + + align:start position:0% +clearly Tolken was a mench + + + align:start position:0% +clearly Tolken was a mench +right in the truest sense of that word. + + align:start position:0% +right in the truest sense of that word. + + + align:start position:0% +right in the truest sense of that word. +Uh but but also because I I think it + + align:start position:0% +Uh but but also because I I think it + + + align:start position:0% +Uh but but also because I I think it +speaks to the kinds of intellectual + + align:start position:0% +speaks to the kinds of intellectual + + + align:start position:0% +speaks to the kinds of intellectual +influences that are in this case + + align:start position:0% +influences that are in this case + + + align:start position:0% +influences that are in this case +informing two very different genres, + + align:start position:0% +informing two very different genres, + + + align:start position:0% +informing two very different genres, +fantasy literature, right? And you know + + align:start position:0% +fantasy literature, right? And you know + + + align:start position:0% +fantasy literature, right? And you know +on the least history, could you possibly + + align:start position:0% +on the least history, could you possibly + + + align:start position:0% +on the least history, could you possibly +get two different genres, right? And yet + + align:start position:0% +get two different genres, right? And yet + + + align:start position:0% +get two different genres, right? And yet +um the the kind of intellectual millu + + align:start position:0% +um the the kind of intellectual millu + + + align:start position:0% +um the the kind of intellectual millu +that is motivating them is clearly very + + align:start position:0% +that is motivating them is clearly very + + + align:start position:0% +that is motivating them is clearly very +similar. Okay. End of sermon. + + align:start position:0% + + + + align:start position:0% + +Do we have a rough sense of what we're + + align:start position:0% +Do we have a rough sense of what we're + + + align:start position:0% +Do we have a rough sense of what we're +doing for next week? + + align:start position:0% + + + + align:start position:0% + +Yeah. I don't mean I don't mean next + + align:start position:0% +Yeah. I don't mean I don't mean next + + + align:start position:0% +Yeah. I don't mean I don't mean next +week. Sorry. + + align:start position:0% + + + + align:start position:0% + +Um Yes. And you know, it's not clear to + + align:start position:0% +Um Yes. And you know, it's not clear to + + + align:start position:0% +Um Yes. And you know, it's not clear to +me how you should be responsible for + + align:start position:0% +me how you should be responsible for + + + align:start position:0% +me how you should be responsible for +doing that, but you'll figure it out. \ No newline at end of file diff --git a/tl7q_VZ3eIQ.txt b/tl7q_VZ3eIQ.txt new file mode 100644 index 0000000000000000000000000000000000000000..695c5030eb38347396f76997748dff19e61920a8 --- /dev/null +++ b/tl7q_VZ3eIQ.txt @@ -0,0 +1,2019 @@ +align:start position:0% + +all right so our next thing will be + + align:start position:0% +all right so our next thing will be + + + align:start position:0% +all right so our next thing will be +getting into the electron spin and I + + align:start position:0% +getting into the electron spin and I + + + align:start position:0% +getting into the electron spin and I +want to discuss two things a little bit + + align:start position:0% +want to discuss two things a little bit + + + align:start position:0% +want to discuss two things a little bit +of the Dirac equation and the paola + + align:start position:0% +of the Dirac equation and the paola + + + align:start position:0% +of the Dirac equation and the paola +equation for the electron we need to + + align:start position:0% +equation for the electron we need to + + + align:start position:0% +equation for the electron we need to +understand the electron a little better + + align:start position:0% +understand the electron a little better + + + align:start position:0% +understand the electron a little better +and understand the perturbations the + + align:start position:0% +and understand the perturbations the + + + align:start position:0% +and understand the perturbations the +relativistic Corrections so we will + + align:start position:0% +relativistic Corrections so we will + + + align:start position:0% +relativistic Corrections so we will +consider the power Li equation so how + + align:start position:0% +consider the power Li equation so how + + + align:start position:0% +consider the power Li equation so how +the equation is what we have to do now + + align:start position:0% +the equation is what we have to do now + + + align:start position:0% +the equation is what we have to do now +so what is the power equation it is the + + align:start position:0% +so what is the power equation it is the + + + align:start position:0% +so what is the power equation it is the +first attempt there was to figure out + + align:start position:0% +first attempt there was to figure out + + + align:start position:0% +first attempt there was to figure out +how the Schrodinger equation should be + + align:start position:0% +how the Schrodinger equation should be + + + align:start position:0% +how the Schrodinger equation should be +tailored for an electron so we can also + + align:start position:0% +tailored for an electron so we can also + + + align:start position:0% +tailored for an electron so we can also +think of the power equation as a baby + + align:start position:0% +think of the power equation as a baby + + + align:start position:0% +think of the power equation as a baby +version of the Dirac equation which is + + align:start position:0% +version of the Dirac equation which is + + + align:start position:0% +version of the Dirac equation which is +the complete equation for the electron + + align:start position:0% +the complete equation for the electron + + + align:start position:0% +the complete equation for the electron +so it all begins the motivations by + + align:start position:0% +so it all begins the motivations by + + + align:start position:0% +so it all begins the motivations by +considering what is the magnetic moment + + align:start position:0% +considering what is the magnetic moment + + + align:start position:0% +considering what is the magnetic moment +Natick moment of the of an electron so + + align:start position:0% +Natick moment of the of an electron so + + + align:start position:0% +Natick moment of the of an electron so +it's a question that you've been + + align:start position:0% +it's a question that you've been + + + align:start position:0% +it's a question that you've been +addressing in this course for a while + + align:start position:0% +addressing in this course for a while + + + align:start position:0% +addressing in this course for a while +you know stern-gerlach experiment and + + align:start position:0% +you know stern-gerlach experiment and + + + align:start position:0% +you know stern-gerlach experiment and +how magnetic fields interact with + + align:start position:0% +how magnetic fields interact with + + + align:start position:0% +how magnetic fields interact with +electron so classically we and in + + align:start position:0% +electron so classically we and in + + + align:start position:0% +electron so classically we and in +Gaussian units units if you have a + + align:start position:0% +Gaussian units units if you have a + + + align:start position:0% +Gaussian units units if you have a +current loop and an area a the magnetic + + align:start position:0% +current loop and an area a the magnetic + + + align:start position:0% +current loop and an area a the magnetic +moment is equal to I times the area + + align:start position:0% +moment is equal to I times the area + + + align:start position:0% +moment is equal to I times the area +vector divided by C + + align:start position:0% + + + + align:start position:0% + +you can use that to imagine an object + + align:start position:0% +you can use that to imagine an object + + + align:start position:0% +you can use that to imagine an object +that is rotating and as the object + + align:start position:0% +that is rotating and as the object + + + align:start position:0% +that is rotating and as the object +rotates if it's charged it generates a + + align:start position:0% +rotates if it's charged it generates a + + + align:start position:0% +rotates if it's charged it generates a +magnetic moment and the magnetic moment + + align:start position:0% +magnetic moment and the magnetic moment + + + align:start position:0% +magnetic moment and the magnetic moment +depends on the amount of rotation of the + + align:start position:0% +depends on the amount of rotation of the + + + align:start position:0% +depends on the amount of rotation of the +orbit so it turns out that with a little + + align:start position:0% +orbit so it turns out that with a little + + + align:start position:0% +orbit so it turns out that with a little +classical argument you can derive that + + align:start position:0% +classical argument you can derive that + + + align:start position:0% +classical argument you can derive that +the magnetic moment is related to the + + align:start position:0% +the magnetic moment is related to the + + + align:start position:0% +the magnetic moment is related to the +angular momentum by a relation of the + + align:start position:0% +angular momentum by a relation of the + + + align:start position:0% +angular momentum by a relation of the +farm L so the charge of the object the + + align:start position:0% +farm L so the charge of the object the + + + align:start position:0% +farm L so the charge of the object the +mass of the object C and the angular + + align:start position:0% +mass of the object C and the angular + + + align:start position:0% +mass of the object C and the angular +momentum that's perfectly correct + + align:start position:0% +momentum that's perfectly correct + + + align:start position:0% +momentum that's perfectly correct +classically so people thought that + + align:start position:0% +classically so people thought that + + + align:start position:0% +classically so people thought that +quantum mechanically they expect that + + align:start position:0% +quantum mechanically they expect that + + + align:start position:0% +quantum mechanically they expect that +for an electron or for an elementary + + align:start position:0% +for an electron or for an elementary + + + align:start position:0% +for an electron or for an elementary +particle you would get Q times Q MC + + align:start position:0% +particle you would get Q times Q MC + + + align:start position:0% +particle you would get Q times Q MC +times the spin of the particle so this + + align:start position:0% +times the spin of the particle so this + + + align:start position:0% +times the spin of the particle so this +would be the intrinsic magnetic moment + + align:start position:0% +would be the intrinsic magnetic moment + + + align:start position:0% +would be the intrinsic magnetic moment +of an electron that it seems to have it + + align:start position:0% +of an electron that it seems to have it + + + align:start position:0% +of an electron that it seems to have it +times a fudge factor G that you would + + align:start position:0% +times a fudge factor G that you would + + + align:start position:0% +times a fudge factor G that you would +have to measure because after all the + + align:start position:0% +have to measure because after all the + + + align:start position:0% +have to measure because after all the +world is not classical there's no reason + + align:start position:0% +world is not classical there's no reason + + + align:start position:0% +world is not classical there's no reason +why a classical relation like that would + + align:start position:0% +why a classical relation like that would + + + align:start position:0% +why a classical relation like that would +give you the right exact value of the + + align:start position:0% +give you the right exact value of the + + + align:start position:0% +give you the right exact value of the +magnetic moment of the electron as it + + align:start position:0% +magnetic moment of the electron as it + + + align:start position:0% +magnetic moment of the electron as it +turns out this G happens to be equal to + + align:start position:0% +turns out this G happens to be equal to + + + align:start position:0% +turns out this G happens to be equal to +two + + align:start position:0% + + + + align:start position:0% + +and we get the following so four + + align:start position:0% +and we get the following so four + + + align:start position:0% +and we get the following so four +electrons G happens to be equal to two + + align:start position:0% +electrons G happens to be equal to two + + + align:start position:0% +electrons G happens to be equal to two +so mu is equal to two times minus e the + + align:start position:0% +so mu is equal to two times minus e the + + + align:start position:0% +so mu is equal to two times minus e the +charge of the electron is minus e to MC + + align:start position:0% +charge of the electron is minus e to MC + + + align:start position:0% +charge of the electron is minus e to MC +and the spin of the electron is h-bar + + align:start position:0% +and the spin of the electron is h-bar + + + align:start position:0% +and the spin of the electron is h-bar +over 2 times Sigma the Pauli matrices so + + align:start position:0% +over 2 times Sigma the Pauli matrices so + + + align:start position:0% +over 2 times Sigma the Pauli matrices so +this thing is minus e h-bar over 2 m C + + align:start position:0% +this thing is minus e h-bar over 2 m C + + + align:start position:0% +this thing is minus e h-bar over 2 m C +Sigma mu of the electron so if you have + + align:start position:0% +Sigma mu of the electron so if you have + + + align:start position:0% +Sigma mu of the electron so if you have +a magnetic field a be external the + + align:start position:0% +a magnetic field a be external the + + + align:start position:0% +a magnetic field a be external the +Hamiltonian that includes the energetics + + align:start position:0% +Hamiltonian that includes the energetics + + + align:start position:0% +Hamiltonian that includes the energetics +of the magnetic field interacting with + + align:start position:0% +of the magnetic field interacting with + + + align:start position:0% +of the magnetic field interacting with +the dipole moment is always minus mu dot + + align:start position:0% +the dipole moment is always minus mu dot + + + align:start position:0% +the dipole moment is always minus mu dot +B so in this case it would be e h-bar + + align:start position:0% +B so in this case it would be e h-bar + + + align:start position:0% +B so in this case it would be e h-bar +over 2 m C Sigma dot B that's a + + align:start position:0% +over 2 m C Sigma dot B that's a + + + align:start position:0% +over 2 m C Sigma dot B that's a +Hamiltonian for an electron in a + + align:start position:0% +Hamiltonian for an electron in a + + + align:start position:0% +Hamiltonian for an electron in a +magnetic field something you've used + + align:start position:0% +magnetic field something you've used + + + align:start position:0% +magnetic field something you've used +many many times the most unpleasant part + + align:start position:0% +many many times the most unpleasant part + + + align:start position:0% +many many times the most unpleasant part +of this thing is this G equal to why did + + align:start position:0% +of this thing is this G equal to why did + + + align:start position:0% +of this thing is this G equal to why did +it turn out to be G equal to people knew + + align:start position:0% +it turn out to be G equal to people knew + + + align:start position:0% +it turn out to be G equal to people knew +it was G equal to but why and here we're + + align:start position:0% +it was G equal to but why and here we're + + + align:start position:0% +it was G equal to but why and here we're +going to see the beginning of an + + align:start position:0% +going to see the beginning of an + + + align:start position:0% +going to see the beginning of an +explanation in fact it comes very close + + align:start position:0% +explanation in fact it comes very close + + + align:start position:0% +explanation in fact it comes very close +to an explanation of that through the + + align:start position:0% +to an explanation of that through the + + + align:start position:0% +to an explanation of that through the +power equation that is the power + + align:start position:0% +power equation that is the power + + + align:start position:0% +power equation that is the power +equation is a nice equation you can + + align:start position:0% +equation is a nice equation you can + + + align:start position:0% +equation is a nice equation you can +write and you can motivate and it + + align:start position:0% +write and you can motivate and it + + + align:start position:0% +write and you can motivate and it +predicts once you admit the power + + align:start position:0% +predicts once you admit the power + + + align:start position:0% +predicts once you admit the power +equation it predicts that G would be + + align:start position:0% +equation it predicts that G would be + + + align:start position:0% +equation it predicts that G would be +equal to 2 so that's and that of course + + align:start position:0% +equal to 2 so that's and that of course + + + align:start position:0% +equal to 2 so that's and that of course +happens also for the Dirac equation and + + align:start position:0% +happens also for the Dirac equation and + + + align:start position:0% +happens also for the Dirac equation and +Dirac note is + + align:start position:0% +Dirac note is + + + align:start position:0% +Dirac note is +that and he was very happy about it so + + align:start position:0% + + + + align:start position:0% + +it's quite remarkable how these things + + align:start position:0% +it's quite remarkable how these things + + + align:start position:0% +it's quite remarkable how these things +showed up and the G equal to two was + + align:start position:0% +showed up and the G equal to two was + + + align:start position:0% +showed up and the G equal to two was +perfectly natural so let's see this + + align:start position:0% +perfectly natural so let's see this + + + align:start position:0% +perfectly natural so let's see this +Dirac this pound equation first what is + + align:start position:0% +Dirac this pound equation first what is + + + align:start position:0% +Dirac this pound equation first what is +it well when you do the Schrodinger + + align:start position:0% +it well when you do the Schrodinger + + + align:start position:0% +it well when you do the Schrodinger +equation for a wavefunction you say P + + align:start position:0% +equation for a wavefunction you say P + + + align:start position:0% +equation for a wavefunction you say P +squared over 2m say a free particle free + + align:start position:0% +squared over 2m say a free particle free + + + align:start position:0% +squared over 2m say a free particle free +particle you would put a wave function + + align:start position:0% +particle you would put a wave function + + + align:start position:0% +particle you would put a wave function +is equal to energy systems the wave + + align:start position:0% +is equal to energy systems the wave + + + align:start position:0% +is equal to energy systems the wave +function H on the wave function is equal + + align:start position:0% +function H on the wave function is equal + + + align:start position:0% +function H on the wave function is equal +to the energy times the wave function so + + align:start position:0% +to the energy times the wave function so + + + align:start position:0% +to the energy times the wave function so +for us + + align:start position:0% +for us + + + align:start position:0% +for us +electrum you already know it's a two + + align:start position:0% +electrum you already know it's a two + + + align:start position:0% +electrum you already know it's a two +dimensional hilbert space the state + + align:start position:0% +dimensional hilbert space the state + + + align:start position:0% +dimensional hilbert space the state +space of the up-and-down so it's + + align:start position:0% +space of the up-and-down so it's + + + align:start position:0% +space of the up-and-down so it's +convenient to change this and to say you + + align:start position:0% +convenient to change this and to say you + + + align:start position:0% +convenient to change this and to say you +know what I'm gonna put here something L + + align:start position:0% +know what I'm gonna put here something L + + + align:start position:0% +know what I'm gonna put here something L +taller spinner Kai is a power Li has two + + align:start position:0% +taller spinner Kai is a power Li has two + + + align:start position:0% +taller spinner Kai is a power Li has two +things Taiwan and Akari - and it's a + + align:start position:0% +things Taiwan and Akari - and it's a + + + align:start position:0% +things Taiwan and Akari - and it's a +power Li spinner and this is reasonable + + align:start position:0% +power Li spinner and this is reasonable + + + align:start position:0% +power Li spinner and this is reasonable +so far the spin is defined by two + + align:start position:0% +so far the spin is defined by two + + + align:start position:0% +so far the spin is defined by two +degrees of freedom two basis vectors so + + align:start position:0% +degrees of freedom two basis vectors so + + + align:start position:0% +degrees of freedom two basis vectors so +you've done wave functions for spin and + + align:start position:0% +you've done wave functions for spin and + + + align:start position:0% +you've done wave functions for spin and +the wave functions for spin have these + + align:start position:0% +the wave functions for spin have these + + + align:start position:0% +the wave functions for spin have these +things and each themself can be a + + align:start position:0% +things and each themself can be a + + + align:start position:0% +things and each themself can be a +function of position so that's perfectly + + align:start position:0% +function of position so that's perfectly + + + align:start position:0% +function of position so that's perfectly +reasonable I don't think any one of you + + align:start position:0% +reasonable I don't think any one of you + + + align:start position:0% +reasonable I don't think any one of you +is not very impressed by this so far but + + align:start position:0% +is not very impressed by this so far but + + + align:start position:0% +is not very impressed by this so far but +here comes the funny thing in a sense + + align:start position:0% +here comes the funny thing in a sense + + + align:start position:0% +here comes the funny thing in a sense +here there is a a two by two identity + + align:start position:0% +here there is a a two by two identity + + + align:start position:0% +here there is a a two by two identity +matrix + + align:start position:0% +matrix + + + align:start position:0% +matrix +sitting here so Paola observes the + + align:start position:0% +sitting here so Paola observes the + + + align:start position:0% +sitting here so Paola observes the +following identity if you have Sigma dot + + align:start position:0% +following identity if you have Sigma dot + + + align:start position:0% +following identity if you have Sigma dot +8 and Sigma dot B is equal to a dot B + + align:start position:0% +8 and Sigma dot B is equal to a dot B + + + align:start position:0% +8 and Sigma dot B is equal to a dot B +times 1 plus I Sigma dot a cross B look + + align:start position:0% +times 1 plus I Sigma dot a cross B look + + + align:start position:0% +times 1 plus I Sigma dot a cross B look +these are two vectors a and B and if you + + align:start position:0% +these are two vectors a and B and if you + + + align:start position:0% +these are two vectors a and B and if you +multiply have this proud first this is a + + align:start position:0% +multiply have this proud first this is a + + + align:start position:0% +multiply have this proud first this is a +dot product means Sigma 1 times a 1 + + align:start position:0% +dot product means Sigma 1 times a 1 + + + align:start position:0% +dot product means Sigma 1 times a 1 +Sigma 2 times a 2 Sigma 3 times a 3 so + + align:start position:0% +Sigma 2 times a 2 Sigma 3 times a 3 so + + + align:start position:0% +Sigma 2 times a 2 Sigma 3 times a 3 so +this is a dot product this product here + + align:start position:0% +this is a dot product this product here + + + align:start position:0% +this is a dot product this product here +is a matrix product because this is + + align:start position:0% +is a matrix product because this is + + + align:start position:0% +is a matrix product because this is +already a matrix this is a ready matrix + + align:start position:0% +already a matrix this is a ready matrix + + + align:start position:0% +already a matrix this is a ready matrix +so this is a matrix product and this is + + align:start position:0% +so this is a matrix product and this is + + + align:start position:0% +so this is a matrix product and this is +the result this comes from properties of + + align:start position:0% +the result this comes from properties of + + + align:start position:0% +the result this comes from properties of +the polymer matrices you already know in + + align:start position:0% +the polymer matrices you already know in + + + align:start position:0% +the polymer matrices you already know in +particular their commutator determines + + align:start position:0% +particular their commutator determines + + + align:start position:0% +particular their commutator determines +this piece and the anti commutator the + + align:start position:0% +this piece and the anti commutator the + + + align:start position:0% +this piece and the anti commutator the +term in this piece so here if you have + + align:start position:0% +term in this piece so here if you have + + + align:start position:0% +term in this piece so here if you have +for example Sigma dot P times Sigma dot + + align:start position:0% +for example Sigma dot P times Sigma dot + + + align:start position:0% +for example Sigma dot P times Sigma dot +P since these two vectors are the same + + align:start position:0% +P since these two vectors are the same + + + align:start position:0% +P since these two vectors are the same +in this case you'll get just P squared + + align:start position:0% +in this case you'll get just P squared + + + align:start position:0% +in this case you'll get just P squared +times 1 plus 0 because P times P those + + align:start position:0% +times 1 plus 0 because P times P those + + + align:start position:0% +times 1 plus 0 because P times P those +are two vectors 2 vector operators if + + align:start position:0% +are two vectors 2 vector operators if + + + align:start position:0% +are two vectors 2 vector operators if +you wish but still they commute so this + + align:start position:0% +you wish but still they commute so this + + + align:start position:0% +you wish but still they commute so this +is equal to 0 so your P squared can be + + align:start position:0% +is equal to 0 so your P squared can be + + + align:start position:0% +is equal to 0 so your P squared can be +replaced by Sigma dot P Sigma dot P so H + + align:start position:0% +replaced by Sigma dot P Sigma dot P so H + + + align:start position:0% +replaced by Sigma dot P Sigma dot P so H +the Hamiltonian that is P squared over + + align:start position:0% +the Hamiltonian that is P squared over + + + align:start position:0% +the Hamiltonian that is P squared over +2m times the identity matrix can be + + align:start position:0% +2m times the identity matrix can be + + + align:start position:0% +2m times the identity matrix can be +perhaps better thought a Sigma dot P + + align:start position:0% +perhaps better thought a Sigma dot P + + + align:start position:0% +perhaps better thought a Sigma dot P +then Sigma dot P divided by 2 n + + align:start position:0% + + + + align:start position:0% + +but Sigma dot P so this is the the first + + align:start position:0% +but Sigma dot P so this is the the first + + + align:start position:0% +but Sigma dot P so this is the the first +step you haven't done really much but + + align:start position:0% +step you haven't done really much but + + + align:start position:0% +step you haven't done really much but +you've written the Hamiltonian with a + + align:start position:0% +you've written the Hamiltonian with a + + + align:start position:0% +you've written the Hamiltonian with a +unit matrix here perhaps in a somewhat + + align:start position:0% +unit matrix here perhaps in a somewhat + + + align:start position:0% +unit matrix here perhaps in a somewhat +provocative way in quantum mechanics + + align:start position:0% +provocative way in quantum mechanics + + + align:start position:0% +provocative way in quantum mechanics +when we coupled to electromagnetism + + align:start position:0% +when we coupled to electromagnetism + + + align:start position:0% +when we coupled to electromagnetism +there are simple changes we'd have to do + + align:start position:0% +there are simple changes we'd have to do + + + align:start position:0% +there are simple changes we'd have to do +and we will study that in detail in + + align:start position:0% +and we will study that in detail in + + + align:start position:0% +and we will study that in detail in +about three weeks but today I will just + + align:start position:0% +about three weeks but today I will just + + + align:start position:0% +about three weeks but today I will just +mention what you're supposed to do in + + align:start position:0% +mention what you're supposed to do in + + + align:start position:0% +mention what you're supposed to do in +order to couple to electromagnetism in + + align:start position:0% +order to couple to electromagnetism in + + + align:start position:0% +order to couple to electromagnetism in +order to couple the length of magnetism + + align:start position:0% +order to couple the length of magnetism + + + align:start position:0% +order to couple the length of magnetism +you're supposed to change P wherever you + + align:start position:0% +you're supposed to change P wherever you + + + align:start position:0% +you're supposed to change P wherever you +see by an object you can call pi is some + + align:start position:0% +see by an object you can call pi is some + + + align:start position:0% +see by an object you can call pi is some +sort of more canonical momentum in which + + align:start position:0% +sort of more canonical momentum in which + + + align:start position:0% +sort of more canonical momentum in which +it's equal to P minus Q over C the + + align:start position:0% +it's equal to P minus Q over C the + + + align:start position:0% +it's equal to P minus Q over C the +vector potential is a function of X well + + align:start position:0% +vector potential is a function of X well + + + align:start position:0% +vector potential is a function of X well +people write it like this Q P minus Q PC + + align:start position:0% + + + + align:start position:0% + +so you're supposed to do this + + align:start position:0% +so you're supposed to do this + + + align:start position:0% +so you're supposed to do this +replacement when you're dealing with a + + align:start position:0% +replacement when you're dealing with a + + + align:start position:0% +replacement when you're dealing with a +particle moving in some electromagnetic + + align:start position:0% +particle moving in some electromagnetic + + + align:start position:0% +particle moving in some electromagnetic +field that's the change you must do we + + align:start position:0% +field that's the change you must do we + + + align:start position:0% +field that's the change you must do we +will study that in detail but I think + + align:start position:0% +will study that in detail but I think + + + align:start position:0% +will study that in detail but I think +the obvious question and this moment is + + align:start position:0% +the obvious question and this moment is + + + align:start position:0% +the obvious question and this moment is +the following you say well I'm in + + align:start position:0% +the following you say well I'm in + + + align:start position:0% +the following you say well I'm in +quantum mechanics and I work with P and + + align:start position:0% +quantum mechanics and I work with P and + + + align:start position:0% +quantum mechanics and I work with P and +X those are my upper what is a it's an + + align:start position:0% +X those are my upper what is a it's an + + + align:start position:0% +X those are my upper what is a it's an +operator is it a vector is it what piece + + align:start position:0% +operator is it a vector is it what piece + + + align:start position:0% +operator is it a vector is it what piece +operator but what is a we should think + + align:start position:0% +operator but what is a we should think + + + align:start position:0% +operator but what is a we should think +of this vector potential in general this + + align:start position:0% +of this vector potential in general this + + + align:start position:0% +of this vector potential in general this +vector potential will depend on position + + align:start position:0% +vector potential will depend on position + + + align:start position:0% +vector potential will depend on position +so if you put a magnetic field you + + align:start position:0% +so if you put a magnetic field you + + + align:start position:0% +so if you put a magnetic field you +require a vector potential has some + + align:start position:0% +require a vector potential has some + + + align:start position:0% +require a vector potential has some +position dependence so actually this a + + align:start position:0% +position dependence so actually this a + + + align:start position:0% +position dependence so actually this a +here should be thought as a of X the + + align:start position:0% +here should be thought as a of X the + + + align:start position:0% +here should be thought as a of X the +same way as when you had a potential + + align:start position:0% +same way as when you had a potential + + + align:start position:0% +same way as when you had a potential +that depends on + + align:start position:0% +that depends on + + + align:start position:0% +that depends on +eggs in quantum mechanics we just think + + align:start position:0% +eggs in quantum mechanics we just think + + + align:start position:0% +eggs in quantum mechanics we just think +of that excess and operator so the a is + + align:start position:0% +of that excess and operator so the a is + + + align:start position:0% +of that excess and operator so the a is +an operator because X is an operator and + + align:start position:0% +an operator because X is an operator and + + + align:start position:0% +an operator because X is an operator and +a has X dependence so the Pauli + + align:start position:0% +a has X dependence so the Pauli + + + align:start position:0% +a has X dependence so the Pauli +Hamiltonian H poly H Powell E is nothing + + align:start position:0% +Hamiltonian H poly H Powell E is nothing + + + align:start position:0% +Hamiltonian H poly H Powell E is nothing +else that Sigma dot PI then Sigma dot PI + + align:start position:0% + + + + align:start position:0% + +over 2 m because we said P must be + + align:start position:0% +over 2 m because we said P must be + + + align:start position:0% +over 2 m because we said P must be +replaced by PI so this is the poly + + align:start position:0% +replaced by PI so this is the poly + + + align:start position:0% +replaced by PI so this is the poly +Hamiltonian and it's equal to 1 over 2 M + + align:start position:0% + + + + align:start position:0% + +PI squared PI dot pi times 1 plus I + + align:start position:0% +PI squared PI dot pi times 1 plus I + + + align:start position:0% +PI squared PI dot pi times 1 plus I +Sigma dotted with PI cross 5 + + align:start position:0% + + + + align:start position:0% + +okay here is the computation we need to + + align:start position:0% +okay here is the computation we need to + + + align:start position:0% +okay here is the computation we need to +do what is pi cross pi + + align:start position:0% +do what is pi cross pi + + + align:start position:0% +do what is pi cross pi +you know what PI is is given by this + + align:start position:0% +you know what PI is is given by this + + + align:start position:0% +you know what PI is is given by this +thing so how much is pi cross pi well it + + align:start position:0% +thing so how much is pi cross pi well it + + + align:start position:0% +thing so how much is pi cross pi well it +takes a little computation I'll tell you + + align:start position:0% +takes a little computation I'll tell you + + + align:start position:0% +takes a little computation I'll tell you +what you have to do it's a very + + align:start position:0% +what you have to do it's a very + + + align:start position:0% +what you have to do it's a very +interesting computation it's small it + + align:start position:0% +interesting computation it's small it + + + align:start position:0% +interesting computation it's small it +reminds you of this computation in + + align:start position:0% +reminds you of this computation in + + + align:start position:0% +reminds you of this computation in +angular momentum L cross L you've done + + align:start position:0% +angular momentum L cross L you've done + + + align:start position:0% +angular momentum L cross L you've done +maybe if we written the algebra of + + align:start position:0% +maybe if we written the algebra of + + + align:start position:0% +maybe if we written the algebra of +angular momentum in this language is + + align:start position:0% +angular momentum in this language is + + + align:start position:0% +angular momentum in this language is +equal to I h-bar L that's your + + align:start position:0% +equal to I h-bar L that's your + + + align:start position:0% +equal to I h-bar L that's your +commutation relations of angular + + align:start position:0% +commutation relations of angular + + + align:start position:0% +commutation relations of angular +momentum written like that so pi cross + + align:start position:0% +momentum written like that so pi cross + + + align:start position:0% +momentum written like that so pi cross +pi the caithe component is epsilon IJ k + + align:start position:0% +pi the caithe component is epsilon IJ k + + + align:start position:0% +pi the caithe component is epsilon IJ k +pi I PI J or 1/2 epsilon IJ K PI I + + align:start position:0% +pi I PI J or 1/2 epsilon IJ K PI I + + + align:start position:0% +pi I PI J or 1/2 epsilon IJ K PI I +commutator with PI J this last step it + + align:start position:0% +commutator with PI J this last step it + + + align:start position:0% +commutator with PI J this last step it +can be explained by writing out the + + align:start position:0% +can be explained by writing out the + + + align:start position:0% +can be explained by writing out the +commutator which is PI I PI J minus PI J + + align:start position:0% +commutator which is PI I PI J minus PI J + + + align:start position:0% +commutator which is PI I PI J minus PI J +PI I but with this epsilon those two + + align:start position:0% +PI I but with this epsilon those two + + + align:start position:0% +PI I but with this epsilon those two +terms are the same and it becomes this + + align:start position:0% +terms are the same and it becomes this + + + align:start position:0% +terms are the same and it becomes this +so how much is this thing I'll leave it + + align:start position:0% +so how much is this thing I'll leave it + + + align:start position:0% +so how much is this thing I'll leave it +for you to do it it's a simple thing you + + align:start position:0% +for you to do it it's a simple thing you + + + align:start position:0% +for you to do it it's a simple thing you +have to commute these things and you + + align:start position:0% +have to commute these things and you + + + align:start position:0% +have to commute these things and you +must think of P as derivatives so this + + align:start position:0% +must think of P as derivatives so this + + + align:start position:0% +must think of P as derivatives so this +pi I PI J is I h-bar Q over c di AJ + + align:start position:0% +pi I PI J is I h-bar Q over c di AJ + + + align:start position:0% +pi I PI J is I h-bar Q over c di AJ +minus DJ a I you can see it coming you + + align:start position:0% +minus DJ a I you can see it coming you + + + align:start position:0% +minus DJ a I you can see it coming you +see you have a commutator of two factors + + align:start position:0% +see you have a commutator of two factors + + + align:start position:0% +see you have a commutator of two factors +like that the a with a welcome + + align:start position:0% +like that the a with a welcome + + + align:start position:0% +like that the a with a welcome +the P with P will commute the cross + + align:start position:0% +the P with P will commute the cross + + + align:start position:0% +the P with P will commute the cross +products one but that's just derivatives + + align:start position:0% +products one but that's just derivatives + + + align:start position:0% +products one but that's just derivatives +so therefore you get derivatives of a + + align:start position:0% +so therefore you get derivatives of a + + + align:start position:0% +so therefore you get derivatives of a +anti symmetries and the relatives of a + + align:start position:0% +anti symmetries and the relatives of a + + + align:start position:0% +anti symmetries and the relatives of a +anti symmetries is the curl of a and the + + align:start position:0% +anti symmetries is the curl of a and the + + + align:start position:0% +anti symmetries is the curl of a and the +curl of a is the magnetic field so + + align:start position:0% +curl of a is the magnetic field so + + + align:start position:0% +curl of a is the magnetic field so +that's why this happens so at the end of + + align:start position:0% +that's why this happens so at the end of + + + align:start position:0% +that's why this happens so at the end of +the day when you'll finish this + + align:start position:0% +the day when you'll finish this + + + align:start position:0% +the day when you'll finish this +computational get that pie cross pi is + + align:start position:0% +computational get that pie cross pi is + + + align:start position:0% +computational get that pie cross pi is +just i q-- I H bar Q over Seaton's the + + align:start position:0% +just i q-- I H bar Q over Seaton's the + + + align:start position:0% +just i q-- I H bar Q over Seaton's the +magnetic field + + align:start position:0% +magnetic field + + + align:start position:0% +magnetic field +pretty nice equation so the Pauli + + align:start position:0% +pretty nice equation so the Pauli + + + align:start position:0% +pretty nice equation so the Pauli +Hamiltonian includes H Powell e includes + + align:start position:0% +Hamiltonian includes H Powell e includes + + + align:start position:0% +Hamiltonian includes H Powell e includes +this term which is I Sigma over 2m + + align:start position:0% + + + + align:start position:0% + +dotted with I HQ over C B plus other + + align:start position:0% +dotted with I HQ over C B plus other + + + align:start position:0% +dotted with I HQ over C B plus other +terms I'm just looking at this term + + align:start position:0% +terms I'm just looking at this term + + + align:start position:0% +terms I'm just looking at this term +which has the magnetic field and + + align:start position:0% +which has the magnetic field and + + + align:start position:0% +which has the magnetic field and +therefore look this I with eyes minus + + align:start position:0% +therefore look this I with eyes minus + + + align:start position:0% +therefore look this I with eyes minus +one but Q is minus e so this is e h-bar + + align:start position:0% +one but Q is minus e so this is e h-bar + + + align:start position:0% +one but Q is minus e so this is e h-bar +over 2 m C Sigma dot B which is here + + align:start position:0% +over 2 m C Sigma dot B which is here + + + align:start position:0% +over 2 m C Sigma dot B which is here +which came from G equal to now where I + + align:start position:0% +which came from G equal to now where I + + + align:start position:0% +which came from G equal to now where I +had to say there that G is equal to 2 or + + align:start position:0% +had to say there that G is equal to 2 or + + + align:start position:0% +had to say there that G is equal to 2 or +it came out of out of this calculation + + align:start position:0% +it came out of out of this calculation + + + align:start position:0% +it came out of out of this calculation +the Pauli Hamiltonian knew of this and + + align:start position:0% +the Pauli Hamiltonian knew of this and + + + align:start position:0% +the Pauli Hamiltonian knew of this and +therefore it's great progress that Polly + + align:start position:0% +therefore it's great progress that Polly + + + align:start position:0% +therefore it's great progress that Polly +Hamiltonian but it suggests to us that + + align:start position:0% +Hamiltonian but it suggests to us that + + + align:start position:0% +Hamiltonian but it suggests to us that +we can do things still even better as + + align:start position:0% +we can do things still even better as + + + align:start position:0% +we can do things still even better as +Dirac did \ No newline at end of file diff --git a/uCK1z-h7Jbc.txt b/uCK1z-h7Jbc.txt new file mode 100644 index 0000000000000000000000000000000000000000..fde6b3efd9a7d85c8078120dcf13d369ce115b53 --- /dev/null +++ b/uCK1z-h7Jbc.txt @@ -0,0 +1,2621 @@ +The following content is +provided under a Creative + +Commons license. + +Your support will help MIT +OpenCourseWare continue to + +offer high-quality educational +resources for free. + +To make a donation or view +additional materials from + +hundreds of MIT courses, visit +MIT OpenCourseWare at + +ocw.mit.edu. + +PROFESSOR: Let's get +right into it. + +So last day, we started looking +at Roentgen again and + +the generation of x-rays, which +we saw occurred when we + +operate the gas discharge tube +at high voltage and low + +pressure and this is the +image that we saw + +of his wife's hand. + +Birth of medical radiography. + +And we started looking at the +origin of x-rays and we + +started looking at the energy +level diagram of the target + +anode in the gas discharge tube +and this is the energy + +level diagram of the target. + +So the ballistic electron-- + +I'm calling it incident-- + +this is the electron that's +making its journey across the + +x-ray generating tube. + +It left the cathode and it's +moving across and crashing + +into the anode. + +So this is the target +or the anode. + +So let's label it as such. + +So we're looking at one of these +mixed metaphors, where + +we've got both a Cartesian image +here of the electron and + +we've got an energy image. + +So this is the target or it's +the anode and it's charged + +positively and so the +electrons are + +crashing into it. + +And we reason that what would +happen is, if the electrons, + +the ballistic electrons, had +high enough energy, they could + +actually dislodge 1s electrons +and when they do so, they make + +the conditions for a cascade. + +So you can see electrons falling +from n equals 2 to n + +equals 1 and when they do +so, they emit radiation. + +They emit photons and these +photons are called K alpha. + +K because the final shell +number was n equals 1. + +And remember, the +spectroscopists + +prefer to use letters. + +So when the electron ends at n +equals 1, that's n final, we + +call it a K photon. + +And furthermore, the subscript +alpha means that the delta, + +the n initial to n final +is only one. + +So when you go from 2 to +1, you get the K alpha. + +And less likely but still +possible is the transition + +from 3 down to 1. + +So it's still called a K photon +because the electron + +that generated the photon ended +in the K shell, but it + +traveled from a delta n +of 2, went from 3 to 1 + +so that's a K beta. + +Over here, obviously if we have +enough energy to kick out + +K shell electrons, we have +enough energy to kick out L + +shell electrons. + +And so if we lose an L shell +electron and we have a + +cascade, then anything that +ends in n equals 2 will be + +called an L photon. + +If it comes from 3 to 2, +that's a delta of 1. + +That's the L alpha. + +It it falls 4 to 2, that's +a delta of 2. + +That's the L beta. + +And so you can see you +get a set of lines. + +And that set of lines +looks like this. + +We can plot a spectrum of this +entire set of lines, which + +will be characteristic of the +identity of the target. + +And I think I showed you last +day that it's going to look + +like this, where we will plot +intensity and the intensity on + +a spectrum is related to the +frequency of occurrence and on + +the abscissa, we're going to +have some kind of energy + +coordinate. + +We can put lambda increasing +from left to right, which + +means energy increases +from right to left. + +And we saw that we have this +family of lines where we have + +a discrete line at the energy +of K alpha and a second line + +at the energy associated with K +beta and K beta has a higher + +energy, therefore, a lower +wavelength, and the relative + +heights related to the relative +frequency, again, not + +to scale, but still the general + +relationship is correct. + +The likelihood of falling from +2 to 1 is higher than falling + +from 3 to 1 and so you'd expect +to have the intensity + +of the K alpha line greater than +the intensity of the K + +beta line and the L lines have +to be of lower energy because + +transitions 3 to 2 are less +energy than 2 to 1 so we + +expect those lines to be out +here and again, a relative + +frequency where the L alpha has +a slightly lower energy + +and L beta has a slightly lower +frequency of a current. + +So that's the spectrum and this +we call characteristic. + +Characteristic of what? + +Of the identity of the +anode or the target. + +This is generating the x-rays. + +So if I want x-rays of this +value of wavelength, I choose + +the target appropriately. + +That's why we have the +relationship here. + +And then the other +thing is that-- + +it's obvious, but I just +want to make sure that + +we put it up here-- + +it's quantized because we're +looking at the photons coming + +at discrete values of energy. + +So that's what we +speculated on. + +Are there any data? + +The answer is yes and the data +come from a young man by the + +name of Henry Moseley. + +He was doing his PhD +up in Manchester. + +He was is working +for Rutherford. + +Rutherford was his PhD thesis +supervisor and 1913, 1914, he + +was making systematic +measurements. + +He was conducting a systematic +study of the characteristic + +spectra of no fewer than +38 elements of + +the Periodic Table. + +And what did we learn from +his measurements? + +Learned from his measurements +that there's was a pattern + +here and here's what the pattern +is that Moseley found. + +He found that if he took +the value of-- + +I'm going to just +take one line. + +If he took all of the K alpha +lines from 1K alpha per + +element and he plotted the value +of the wave number of a + +particular line, he found that +the value of the wave number + +of a particular line scaled +with the identity of the + +element by the square of +the proton number. + +So, for example, we would +have, say here we + +started with aluminum. + +So aluminum proton numbers +13 so 13 squared. + +And he went all the +way up to gold. + +Didn't do all of them but +he did, as I say, 38 + +from one to the other. + +And these are discrete values. + +You have different elements here +and gold is up here and + +he found that he could take the +set of data for, say, all + +the K alphas and they +lie on a line-- + +new bar-- + +as if proportional to the square +of the proton number + +and he did the same +with other lines-- + +say, L alpha and so on-- + +found that they lie on a line. + +So what does all of this mean? + +Well, let's take a look. + +Here's the image of the paper. + +High-frequency spectra +elements. + +Henry Moseley, Master's degree, +so he's working on his + +PhD, and the data were +taken as follows in + +photographic plates. + +And so by trigonometry, you +can figure out what the + +wavelength would be of the line +that would go to this + +degree of distortion, et +cetera, et cetera. + +It's a beautiful set of lines. + +Look at how these +date are posed. + +So there's calcium. + +Scandium is frightfully +expensive so you + +don't see it here. + +Then there's titanium, vanadium, +chromium, manganese, + +and as you change the element, +the wave number, the + +wavelength, the energy of all +of these lines changes + +systematically in accordance +with the square of the proton + +number, and we got over +here to copper. + +Next one is zinc. Zinc melts at +420 degrees Celsius, which + +is relatively low melting. + +And under the bombardment +of electrons-- + +the bombardment of zinc would +cause it to melt and so rather + +than work with zinc, he instead +worked with brass + +because brass is an alloy +of copper and zinc-- + +and look carefully. + +You can see that brass has +four lines, two lines + +identical to the lines of copper +and these two new lines + +are the lines associated with +zinc. And I mentioned last day + +that you could actually +deconvolve the complex spectra + +and identify the constituent +elements. + +So this was really fantastic, +really fantastic. + +Si what did we learn +from all of this? + +What did we learn +by these data? + +well, first of all, corrected +Mendeleyev What + +do I mean by that? + +Not here to say bad things +about Mendeleyev, but + +Mendeleyev had told us that +periodicity is a function of + +the atomic mass. + +That's what Mendeleyev said. + +Periodicity is a function +of atomic mass. + +And now Moseley says no. + +Moseley says that +periodicity is a + +function of proton number. + +And you can see here-- + +I wanted to show you the-- + +this is an image taken +from his paper. + +He worked for Rutherford. + +These people were brilliant +experimentalists and + +so here he's got-- + +the cathode is up +here at the top. + +You see cathode of x-ray tube +and the feed through and so + +on, so the anode is down here +and it's connected and so on, + +and rather than take the x-ray +tube apart in order to change + +the target, he went to the +toy store and he bought-- + +this is the train from the toy +store and he's got different + +elements seated next to each +other on the flat car of the + +train and he's got feedthroughs +with silk fishing + +line so that after he's done +the experiment with one + +element, he can pull the train +car over and change the anode + +without having to take +the apparatus apart. + +These guys were very, very +good experimentalists. + +So here's from his paper. + +The author intends first to make +a general survey of the + +principal types of +high-frequency radiation and + +then to examine the spectra of +a few elements in greater + +detail with greater accuracy. + +The results already obtained +show that such data have an + +important bearing on the +question of the internal + +structure of the atom and +strongly support the views of + +Rutherford and Bohr. + +It's 1913. + +Remember, that's when +Bohr paper came out. + +All these people were working +in the lab at the same time, + +supporting each other. + +You see, this doesn't make any +sense with a Plum Pudding + +Model, does it? + +See, he continues: "We have here +a proof that there isn't + +the atom of fundamental +quantity, which increases by + +regular steps as we pass from +one element to the next. + +This quantity can only be the +charge on the central positive + +nucleus on the existence of +which we already have definite + +proof." + +See, not only-- remember, the +Plum Pudding Model has this + +big blob of positive +charge nests. + +There are no protons. + +In the nuclear model, we have +a nucleus that has positive + +charge and he's saying, I know +there's positive charge, and + +it increases as you go from +one element to the next. + +We are therefore led by +experiment to view that N-- we + +use the letter Z today. + +He's using capital N. + +N is the same as the number of +the place occupied by the + +element in the periodic +system. + +This atomic number-- for the +first time, the term atomic + +number is used. + +That's why I was being coy here +and I kept saying proton + +number, because that's +the way they knew it. + +Now he's say, this is +the social security + +number of the element. + +Proton number is then for +hydrogen 1, helium 2, lithium + +3, calcium 20, zinc +30, et cetera. + +We can confidently predict-- + +look at-- this is the +masters student and + +he's going on a limb. + +He says: "We can confidently +predict that in the few cases + +in which the order of the atomic +weights A clashes with + +the chemical order of the +periodic system, the chemical + +properties are governed by N, +while A itself is probably a + +complicated function +of N." He's right. + +You look at the Periodic +Table. + +You say, yeah, yeah, they just +go in descending mass or + +ascending proton number. + +Look carefully. + +Potassium has a lower +mass than argon. + +And nobody's to-- + +well, if you were Mendeleyev, +you'd say, go back + +and measure it again. + +Well, they have measured it. + +These are the accurate values +and no one's going to put + +potassium underneath neon, but +it comes next in the order of + +ascending atomic mass. + +Cobalt and nickel-- +nickel actually + +weighs less than cobalt. + +But they're transition elements +so who cares if you + +get those two mixed up? + +You find them in stainless +steel. + +It doesn't matter. + +This is a good one. + +Iodine is lower mass +than tellurium. + +Iodine is a halogen. + +It belongs under fluorine, +chlorine and bromine. + +You're not going +to put it under + +oxygen, sulfur, selenium. + +But look, there's the data. + +And then last one that Moseley +couldn't have known about is + +transuranic synthetic element, +but that's just the fourth + +case in the periodic table. + +So that gets you the last wedge +in Trivial Pursuit. + +What are the four pairs +of elements + +that are out of sequence? + +OK. + +So now we can say that proton +number is the atomic number. + +It's the identity. + +So that comes out of Moseley, +comes out of his work. + +The second thing that he did as +a result of his study of 38 + +elements is he figured out +what to do with the + +lanthanides. + +Remember our friends, +the lanthanides. + +Place the lanthanides +correctly in + +the Periodic Table. + +Many of the lanthanides have +a valence 3 so people were + +struggling. + +They were putting them +underneath aluminum. + +They didn't know what +to do with them. + +He placed the lanthanides +correctly in + +the Periodic Table. + +And it's not as though +these were brand new. + +Lanthanum itself had been first +isolated in 1839, and + +all through the 1800s, they +were picking them up and + +finally, lutetium was the +last one discovered, + +categorized in 1907. + +But people didn't know what to +do with them and remember, + +they were obsessed with atomic +mass measurements. + +So I'm going to give you this. + +I'll give you this piece +of information. + +There's the atomic mass of +lanthanum, and the atomic mass + +of lutetium is 174.97. + +So what? + +I don't know what to do +with that information. + +That doesn't help me at all. + +But now comes Moseley and he +says, we're not talking about + +atomic mass. + +We're talking about +atomic number. + +So now I tell you this +atomic number is 57. + +So where do you put it? + +Duh, you put it right +next to barium. + +There's no debate. + +And furthermore, this +one is 71-- + +atomic number. + +Well, if this is 71 and +this is 57, I can + +tell you with impunity-- + +how many lanthanides +are there? + +There's 14 of them from +here to there. + +OK. + +14 elements, which makes sense +because in s we've got one + +orbital, in p we've got three +orbitals, and d we've got 5 + +orbitals and these are f +and there's 7 orbitals. + +7 times 2 is 14. + +Everything makes sense. + +And the last thing that's a +corollary to the item two-- + +we were able to give +uranium its proper + +atomic number is 92. + +So now I ask you, how many +elements are there up to + +uranium starting +with hydrogen? + +92. + +All of this comes as the +result of Moseley's + +experiments. + +But it's not over yet because he +worked for Rutherford, and + +Rutherford pushed his +people really hard. + +He wasn't abusive, but he +brought out the best in them. + +So who else was in +the building? + +Bohr, and what were +they doing? + +They were doing theory and so +he said, well, that's nice, + +but he says, I want those things +fit to an equation. + +So Moseley said, all right. + +I'm going to use-- + +there's already an equation in +the building for a new bar. + +It's the Rydberg equation. + +So I'm going to use a +Rydberg-like equation. + +So this is what he does. + +This is Moseley's fit. + +He goes the wave number of +whatever the line is-- whether + +it's K alpha, L alpha, what have +you-- is going to go as + +the product of the Rydberg +constant-- + +1/NF squared minus +1/NI squared. + +So far that's just the +Rydberg equation. + +But now comes Moseley's +contribution. + +We're going to put z squared, +but one more piece. + +Notice the way I've +drawn those lines. + +They don't go through +the origin, do they? + +There's an offset. + +So he said, let's allow +for the offset-- + +z minus sigma quantity square. + +And this is known as +Moseley's Law. + +And you've got values +for sigma. + +sigma for K alpha equals 1 and +for L alpha equals 7.4. + +So now I can-- + +with impunity, you give +me the wavelength. + +I can get the wave number-- it's +1 over the wavelength and + +I can plug into this equation +and identify the element or + +turn it around if I want to get +wavelength radiation of, + +say, 1.25 angstroms, I can plug +into this equation and + +come up with the z, which will +tell me what the target + +element choice should be. + +So let's go and plug this in +because we're only going to + +look at these two. + +So we can say that the wave +number for K alpha-- + +it's always going to be 1/2 +squared minus 1/1 squared, + +which is always going +to come up 3/4. + +So it's 3/4 times Rydberg +z minus 1 squared. + +So this is for the 2:1 or, if +you like, L to K transition + +and then the other one +of interest here + +is nu bar of L alpha. + +nu bar of L alpha's going to +be 1/3 squared minus 1/2 + +squared, which becomes 536 times +the Rydberg constant z + +minus 7.4 squared and this +is for the transition 3:2 + +or KLM, M to L. + +OK. + +So there it is. + +And now, what's the significance +of all of this? + +I try to give a physical +significance of this sigma, + +which is known as the +screening factor. + +We're going to call sigma here +the screening factor. + +You'll see why in a second. + +Why are we calling it the +screening factor? + +So let's consider what's +happening in the case of the K + +alpha lines. + +Let's look at K alpha +generation. + +So not to scale. + +Let's draw-- + +here's the nucleus with all of +its z positive charges and + +then I'm going to draw the +K shell, and its got two + +electrons in it, and I'm going +to show there's a hole here. + +Because without this +hole, there's no + +reason for the cascade. + +And then I'm going to draw the +L shell and it's got-- what? + +There's 2 from the s, 2s, +and then 6 from the 2p. + +At most. I know this is +a terrible model. + +It violates all kinds of things, +but it's as complex as + +it needs to be for the +explanation I'm about to give + +and I don't want to load you +down with a whole bunch of + +extraneous information. + +So consider the electrons +in the L shell. + +They see the electron vacancy +in the K shell and they're + +going to fall down. + +What's the Coulombic +pull of the nucleus + +on the L shell electrons? + +Can you see that it's not z +plus, but at z plus screened + +by 1 minus. + +So the nuclear charge +is mediated-- + +in other words, it's reduced by +1 thanks to the presence of + +the one negative charge here. + +So these electrons in L shell +feel z less 1 and hence, we + +get z minus 1 as screening +factor. + +It's plausible. + +It's at least physically +consistent. + +Now let's look at +the next one. + +That's the transition +from M to L. + +OK. + +So we get to M. + +We've got 18 electrons, up to +maximum of 18, and if they're + +going to fall down to n equals +2, there needs to be at least + +one vacancy here. + +So now let's use +the same logic. + +So an electron in the m shell +sees the positive charge of + +the nucleus mediated by the +electrons between the shell n + +equals 3 and the nucleus. + +Now, I don't know how many +electrons there are. + +What's the extreme case here? + +Two, four, six, seven, +maybe eight, nine. + +Because this would still give me +the conditions to generate + +the transition 3 to 2. + +I need a vacancy in two. + +I don't need a vacancy in one. + +So this is the maximum. + +so that would be two, four, +six, eight, nine. + +So it could be z minus nine, but +that would mean that all + +of these electrons are on the +same side and I don't have any + +vacancies lower. + +I only have one vacancy here. + +That's an extreme. + +It's not observed. + +And the other extreme is, we +blow away all the electrons. + +So somewhere in between 9 and +0, it turns out it's 7.4. + +I can't predict that it's 7.4, +but 7.4 makes sense. + +If the number were greater than +9, I would be distressed. + +So it makes sense, +rationalizes. + +OK. + +And by the way, if you use this +formula, Moseley's Law-- + +let's bring that back down. + +Remember, I told you I can still +wake up in the middle of + +the night and quote you the +wavelength of copper K alpha + +radiation of five significant +figures. + +I had it drilled into me +in my junior year. + +It's 1.5418 angstroms. +That's the lambda. + +So you can use this formula for +new bar and you know that + +new bar is equal to +1 over lambda. + +So I can use Moseley's Law. + +But true value, lambda-- + +I love this one. + +Watch. + +I'm going to do a triple +subscript. + +Lambda of copper K alpha. + +Isn't that cool? + +Lambda of copper K alpha is +equal to 1.5418 angstroms. And + +if you use Moseley's law, you +get 1.546 and the delta here + +is 1/3 of 1%. + +This man was a positive +genius. + +He was heading pell-mell for +the Nobel Prize, but + +he never got it. + +Why not? + +World War I broke out in 1914 +and Moseley was passionately + +concerned about World War I. + +He wanted to fight. + +He wanted to fight for the +Allied cause and he enlisted + +in the Army. + +Rutherford was furious. + +Rutherford called the Minister +of War, which is analogous to + +the Secretary of Defense and +said, give him a desk job. + +Put him up in Oxford at +a military laboratory. + +And Moseley said, +no, I refuse. + +I'm going to fight. + +And so he was sent +to Gallipoli. + +Gallipoli, as you may know, was +one of the bloodiest sites + +of World War I. + +A quarter of a million Allied +troops and 1/3 sort of a + +million Turkish troops were +killed at Gallipoli. + +Almost 2/3 of a million +people died for that + +little piece of land. + +And on August 10th, 1915, at the +age of 27, Henry Moseley + +was killed in the battle of +Suvla Bay, and they don't give + +Nobel Prizes posthumously, and +so that was the way it ended. + +There's a shot of Henry Moseley +with one of his books. + +The tributes poured in from +all over the world. + +The physics community was +devastated because they knew + +all of this stuff. + +This is the one that really, I +think, says it best. This was + +written by Robert Milliken, +an American. + +He's the one that gave us the +elementary charge of the + +electron, from the University +of Chicago at the time. + +This is what Milliken wrote-- +wrote this to + +Rutherford to read. + +"In a research which is destined +to rank as one of the + +dozen most brilliant in +conception, skillful in + +execution, and illuminating in +results, a young man 26 years + +old threw open the windows +through which we can glimpse + +the subatomic world with a +definiteness and a certainty + +never dreamed before. + +Had the European War no other +result than the snuffing out + +of this young life, that alone +would make it one of the most + +hideous and most irreparable +crimes in history." That's + +when American scientists +knew to write. + +It's beautiful writing. + +What a tribute. + +OK. + +So let's move on. + +Now that we've got Moseley's +Law, we've straightened out + +the Periodic Table. + +So we keep moving. + +And I say, well, I gave you the +drawing of the spectrum. + +Remember the spectrum? + +The spectrum was here. + +You see it? + +I'll put it up real +quick again. + +This was the spectrum. + +OK. + +This is intensity and this is +wavelength and this is K alpha + +and this is K beta and this is +L alpha and this is L beta. + +These are the data coming +from the x-ray tube. + +This happens to be a +molybdenum target. + +Well, it doesn't quite look like +what I've drawn, does it? + +It looks a little bit like +it, but not quite. + +This is definitely there. + +You can see some of these lines +so I'm going to call + +this spectrum A and it looks +like spectrum A has been added + +on top of something else. + +I'm going to call the something +else spectrum B and + +the spectrum B looks +like this. + +And in New England-- + +this curve has a shape because +it's New England. + +This is called whale-shaped. + +I don't know what they call it +in the rest of the country, + +but it even looks +like a whale. + +So you can go on +a whale watch. + +So it starts-- + +it's a sharp front, goes +straight up, hits the maximum + +and then-- are you +ready for this? + +It tails off, all right? + +Whales have tails, yes. + +So what's the difference here? + +Well, the spectrum A, we already +observed is quantized, + +whereas this one isn't. + +This one's continuous. + +It has continuous values up to +this minimum value or, if you + +like, maximum value of energy, +minimum value of wavelengths. + +So we got that. + +It's not quantized. + +And the other thing that's +interesting is-- + +spectrum A, we said, is a +function of the identity of + +the target. + +z of the target, whereas this +one, it's a function of the + +plate voltage. + +So you can see in the diagram +I've shown you, as the plate + +voltage changes, we get a series +of enveloping curves. + +So this is V1 and this is V2-- + +greater than V1. + +So this whale-shaped +thing is somehow + +related to plate voltage. + +And then beyond a certain +critical value, can you see + +when you're down here at 15 or +20,000 volts, all you got is + +the whale-shaped curve? + +But somewhere between 20 and +25,000 volts, you hit a + +threshold and now you switch on +the characteristic lines. + +So with low voltage, you don't +get the characteristic lines. + +You only get the whale-shaped +curve. + +And then beyond a certain +critical value of V, it's as + +though all of a sudden +these lines appear. + +Low voltage, no lines. + +High voltage, you get the +characteristic lines. + +And what can we do here? + +Well, we can compute K alpha, +L alpha by Moseley's Law. + +The continuous spectrum can't +do anything with that, with + +one exception-- + +here. + +So let's look inside and figure +out what's going on. + +We have a proposal here of +what's going on inside that + +target atom. + +So I'm going to make-- + +this could be the molybdenum +target up there. + +So these are molybdenum +atoms. And just as + +in Moseley's figure-- + +so this is body centered +cubic-- + +I can look that up on +the Periodic Table. + +I know this is BCC crystal +structure, molybdenum atom + +sitting here. + +This is the anode. + +It's charged positive and way +up top, I get the cathode. + +So the cathode is shooting off +ballistic electrons and they + +go zooming across the gap and +crash into anode, but up until + +now, we've just said the +anode is some material. + +Now we're going to take one more +peel off the onion and + +say that these are discrete +atoms. It's not continuous + +molybdenum. + +It's molybdenum atoms. + +And what do we know the +molybdenum atom looks like? + +It's got a dense nucleus where +all the positive charge + +resides and then there's this +almost vacuum-like zone with + +the negative charge. + +So when the electron comes in, +this electron sees the + +negative charge around +the molybdenum atom. + +What happens? + +It's deflected. + +Maybe it comes in on a closer +angle and it's scattered + +through a higher angle. + +Maybe it comes in almost +in between and it + +hardly moves at all. + +Now can you see that when you +have a charged species that + +changes direction, that's called +an acceleration, and an + +acceleration gives rise to +an emission of radiation? + +So because the angle +of deflection-- + +so this is low-angle deflection, +this is high-angle + +deflection. + +So low-angle deflection means +low energy emission. + +High angle means high-energy +emission, and the result is + +this continue spectrum that +I've shown you here. + +So this is the result of +low-angle scattering of the + +ballistic electrons. + +This is the result of high-angle +scattering of the + +ballistic electrons, and +somewhere in the middle here + +is the dominant angle. + +I can't calculate this curve +with one exception. + +Imagine the electron comes from +the cathode, and with all + +of its energy is dead on and +stops, gives up all of its + +kinetic energy to a photon. + +That's the maximum amount +of energy possible. + +Let's look at that. + +That's the case where an +electron comes in, stops dead + +here and then emits +the photon. + +Sp the kinetic energy +is translated + +into the photon energy. + +So we can do that one. + +That's a straightforward +calculation. + +So the energy of the +incident electron-- + +E of the incident electron is +equal to product of the charge + +on the electron and +the plate voltage. + +Well, the charge on the electron +is the elementary + +charge and the plate voltage +is whatever it is, and I'm + +going to equate that with the +energy of the emitted photon, + +and that's equal to +hc over lambda. + +So now I can cross multiply and +I can call this the lambda + +of the shortest wavelength. + +That's the shortest wavelength +on the whale-shaped curve. + +So by algebra, you're going to +get the product of the plane + +constant times the speed +of light divided by the + +elementary charge times the +plate voltage, which turns out + +to be 12,400 divided by plate +voltage where the wavelength's + +given in angstroms. + +Just try it. + +If you put 10,000 volts, you're +going to get 1.24 + +angstroms, which is smack dab in +the middle of the x-region + +of the spectrum, and this is +called the Duane-Hunt Law. + +That's the only thing +we can compute in + +the continuous spectrum. + +So I can get this one. + +Lambda shortest wavelength, +because shortest wavelength is + +maximum energy. + +Now there's a fancier name for +this whale-shaped curve, and + +it's the scientific community's +term, and it's a + +German word. + +It's called bremsstrahlung. + +I love it. + +You need to know this. + +You can impress your +friends at parties. + +What does bremsstrahlung mean? + +Brems is the German word for +brake, as when you put on the + +brakes of a car. + +And strahl, strahl is +the word for ray. + +And ung is like ing. + +So this is raying radiation +and this is the + +radiation of braking. + +So the electrons are coming in +and when they come up against + +the negative charge of the outer +shell the target atom, + +they are slamming on the +brakes and skidding + +everywhere. + +So this is what bremsstrahlung +means: braking radiation. + +So we're going to call-- + +I'm going to put a B here-- + +see that? + +I was thinking ahead. + +B is bremsstrahlung. + +OK. + +So we've got a lot going +here. for us. + +I think we've explained +a fair bit. + +Now I want to talk about +modern x-ray tubes. + +What do modern x-ray tubes have +that these primitive ones + +that Moseley worked +with and Roentgen + +worked with didn't have? + +So I want to show you that the +modern x-ray tube is the + +result of improvements +made by an MIT alum. + +His name was William Coolidge, +and he's the class of '96-- + +1896. + +And he made a number +of improvements. + +He actually taught for awhile +then eventually spent a good + +part of his professional career +working as a research + +scientist at the General +Electric Labs out in + +Schenectady. + +If you go down to the lobby of +Building 6, on the south side + +of the lobby, there's +a showcase. + +Look inside the showcase. + +You'll see there's a little +display in honor of Coolidge. + +So what's the first thing +Coolidge did? + +He was an engineer so he was +thinking about making things + +more efficient. + +First thing he did is he turned +the discharge tube into + +a vacuum tube. + +Remember, Roentgen worked at +low pressure, but there was + +still gas, and he was blinded +by the light and so on. + +This means you don't get any +visible light, and secondly, + +it's more efficient because if +you've got the tube like this + +with the two electrodes, the +feedthroughs and you've got + +gas inside, some of the +electrons are crashing into + +the gas molecules, +and we don't care + +about the gas molecules. + +We want to get the electrons +crashing into the target. + +So by going to vacuum, this +improves the efficiency. + +No glow in the visible and +higher energy efficiency. + +More x-rays out per +unit power put in. + +What's the second +thing he did? + +Second think he did +was hot cathode. + +Remember, you're trying to rip +the electrons out of the + +cathode and send them +on their journey. + +So Coolidge reasoned that if you +heated the cathode, you'd + +weaken the bonds, and the +electrons would come off. + +They'd boil off much +more readily, OK? + +Raise temperature to reduce bond +energy, to reduce binding + +energy of the electrons. + +The electrons in the cathode +makes them easier to boil off. + +Think I've got a cartoon +of that. + +Yeah, here it is. + +So here's the tube lying +on its side. + +So the cathode is over +here to the left. + +It's negative. + +Here's the anode to the right. + +That's this purple thing here +and the electrons are moving + +from left to right +and so he's got-- + +see, you can have multiple +electrical signals going + +through the same conductor. + +It's not the same. + +You can't have an AC +waveform and a DC + +waveform in the same conductor. + +So you've got a big DC voltage +between the cathode and the + +anode and you'd got a separate +little circuit going through + +the cathode, running almost +like a toaster to + +make it super hot. + +So the potential between here +and here is 35,000 volts. + +The potential along this stretch +of real estate might + +be several hundred volts, +and furthermore, this + +could be an AC signal. + +It's Coolidge. + +He was smart. + +So this makes this hot and now +for per given voltage, you get + +much more yield of +the electrons. + +So that was pretty good. + +I like that. + +Smart. + +Third thing he did was he heated +the cathode and he + +cooled the anode. + +Water-cooled anode. + +Why? + +You got to dissipate the heat. + +All these electrons crashing +into the anode. + +You raise the temperature of +that anode so high you'll melt + +it and so they had to run the +tubes intermittently. + +They just get a decent signal. + +You have to take these x-ray +measurements over a long + +period of time because the +amount of x-rays you get is + +small, but you have to keep +shutting the thing down. + +Otherwise, you melt +through the anode. + +So he put that on a water-cooled +copper hearth and + +was able to run continuous. + +Continuous operation. + +No more pulse current. + +But sometimes when nature +hands you a + +lemon, you make lemonade. + +So I'm going to turn +this thing around. + +I'll say, hey, wait a minute. + +I don't want any water-cooled +copper anode. + +Suppose I want to weld +some titanium. + +Titanium melts at 1675 degrees +Centigrade and it's got a + +voracious appetite for oxygen. + +Well, this thing's +a vacuum tube. + +So what if I were to take my +part and I put the two pieces + +of titanium in the path of an +electron beam and I don't cool + +the titanium? + +Eventually, I get the +temperature so high that I can + +weld titanium. + +This is the birth of electron +beam welding. + +And that's how you weld +refracting metals. + +You get one of those titanium +bicycle frames + +that cost about $4,000. + +It might be tungsten +inert gas. + +It might be electron +beam, depending. + +So that's the flip side +of the technology. + +By the way, if you were in +attendance observing + +electronic beam welding, what +do you think is being + +generated in the electron +beam welding apparatus? + +X-rays, by the boatload + +So there's a fourth thing-- +maybe the most important thing + +that Coolidge came up +with-- shielding. + +You see the yellow here? + +That's lead shielding. + +Why did he choose lead? + +Well, it's got a very high z. + +That means it's got many +energy levels. + +So that if you start looking at +the energy level diagram of + +lead, you've got lots of +action up in here. + +So what can happen? + +When the x-rays come with their +high energy, the x-rays + +from the tube on their way out +to get you, and everybody + +standing observing +this marvel. + +They excite electrons inside. + +So these x-rays are absorbed. + +The electrons inside the lead +rise, cascade down and now + +they come out. + +And what's the difference +in energy between + +the x-ray and these? + +The ones up here are +much lower energy. + +So this is, if you like, +a frequency shifter + +or an energy shifter. + +So now we're using +photons to excite + +electrons to generate photons. + +And that's how the +shielding works. + +So you want to absorb +and re-emit. + +And while we're on the topic, he +gave us lead shielding and + +he gave us beryllium windows +because they were using + +silicate glass, just as you +use in your home, but the + +silicate glass was absorbing +some of the x-rays. + +So to get higher efficiency, +he chose beryllium. + +Why did he choose beryllium? + +Well, it's got a low z. + +So that means it has +few energy levels. + +So therefore, there's less +absorption and re-emission-- + +again, higher efficiency. + +I think this was taken from +one of the other readings. + +So they flipped it around. + +See, here you can see the +cathode here, the anode. + +That's one of these things. + +All right. + +So the window is up here. + +You don't use lithium because +lithium is unstable in the air + +unless you had a giant room of +humidity set at a dew point of + +minus 38 degrees, see, +and then you can + +use a lithium window. + +Otherwise, you use beryllium +and lead down here. + +Why'd he choose lead? + +Well, you're pretty much at the +bottom of the naturally + +occurring elements in +the Periodic Table. + +So it's the cheapest of +all of these heavies. + +All right. + +So now let's take a few minutes +and talk about the use + +of x-rays in characterizing +art. + +So this painting here at once +time was arguably one of the + +most recognizable paintings +in the western world. + +It's The Angelus by +Jean-Francois Millet. + +It was painted at 1857 to 1859 +on commission for an insurance + +company here in Boston. + +The Boston Brahmins loved BA's +paintings of rural life in + +19th century France. + +And this is couple of peasants +who are giving thanks to God. + +The Angelus is a prayer, and +they're thanking God for this + +pitiful bounty of potatoes +evident. + +Salvador Dali, as an art +student, was required to paint + +this as part of training. + +You know how when you learn to +play the piano, you reproduce + +the works of the +Grand Masters. + +So when you go to art school, +you have to paint. + +He hated this painting. + +For many years, it was here +in Boston, and then it was + +repatriated around World War I, +it hung in the Louvre, and + +then ultimately, now it's +in the Musee d'Orsay. + +In 1963 when Dali was at the +peak of his career, he asked + +the curator of the Louvre +if she would have + +this painting x-rayed. + +He said this painting +spooks him. + +He doesn't like this painting. + +And they x-rayed the painting. + +What did they find? + +They found that it had been +painted over down here. + +Wasn't an art forgery, Millet +himself had painted it over. + +You may have heard two years ago +there was this art find. + +It was a van Gogh painting. + +They found that van Gogh had +painted over one of his own + +paintings that had never been +seen before even though the + +pencil sketches survived, so +they assumed that maybe the + +painting was destroyed +in World War II + +or some such thing. + +It turns out that van Gogh was +so poor at one point that he + +valued the canvas over the art, +and he took his previous + +painting, and he painted +over it. + +OK. + +So this was going on here. + +This is the truth. + +Now my speculation begins. + +So what was underneath +here initially? + +It was the casket of a baby. + +Look at the pose. + +These people don't look like +they're happy with their + +bounty of harvest. +They're grieving. + +This was this futility +of peasant life. + +It was a hard life and +they lost their baby. + +So imagine Millet paints this, +puts it on a boat, it comes + +over to Boston, they unveil it, +and the directors of the + +insurance company go, we can't +hang this in the lobby of an + +insurance company. + +That's my speculation. + +It didn't take him three years +to paint this thing. + +I think it spent most of +its time on the boat. + +They sent it back +and said fix it. + +So he put the basket +of potatoes. + +That's my theory. + +All right, look at the pose. + +This is from the Galleria +Borghese in Rome. + +I was there about two years +ago and saw this and went, + +wow, referential. + +You see, everything's +been said. + +All of art has been said. + +Now we're just recasting it. + +So now here's Dali's revenge. + +Now this is what he paints. + +You see the man is shorter +than the woman. + +His hat is down a little bit +below the waistline. + +There's all sorts of +psychosexual things going on + +here, but we're running +out of time. + +So here's Dali and his father +and his dad is saying, see, + +this is life, et cetera, +et cetera. + +So you can see the reference. + +See, man taller here, woman +taller, et cetera, et cetera. + +Have you seen this one? + +The Hallucinogenic Toreador. + +OK, he went outside one day in +Manhattan to buy some pencils. + +There was a company called the +Venus Pencil Company, you see. + +And so he came back and made +this trompe l'oeil. + +So this is the toreador. + +Do you see the breast +here is the nose? + +There is the face. + +There are the flies of the +Thames and here is + +the cape and so on. + +Symmetry plane-- all of those +Venuses facing back, these + +Venuses facing forward. + +There's the bull. + +The life force of the +bull is a crystal. + +What is the crystal structure? + +It's one of the 14 +Bravais lattices. + +If you ignore color, it's +simple cubic, isn't it? + +And if you don't believe +me, check. + +And if you don't appreciate +it, study. + +Here's the symmetry plane. + +Atoms, atoms, fly, fly +et cetera, et cetera. + +What else do we have here? + +Oh, this is the one he painted +on the occasion of the + +revelation of the structure +of DNA. + +It's hard to see, but +over here is the + +double helix of DNA. + +This is his wife Gaia and here +are people standing in cubic + +arrays with guns pointing +at each other. + +And the point that he's making +is that now that we've + +discovered the instruction set +for reproduction of life, not + +just human life, but life, we +are still at a point where we + +can't resist killing +each other. + +So this was the point and he +chose to use cubic arrays, and + +I would venture to say +this is simple cubic. + +If you put a fifth person here, +it would be-- are you + +ready for this? + +Body-centered cubic. + +Oh, yes! + +And there's more, but I think +we're running out of time so I + +think at this point we will +dismiss the class. \ No newline at end of file diff --git a/usMPXTDOIn0.txt b/usMPXTDOIn0.txt new file mode 100644 index 0000000000000000000000000000000000000000..8aff98322cb916004c4cb49924205081bb6770a9 --- /dev/null +++ b/usMPXTDOIn0.txt @@ -0,0 +1,273 @@ +Another service provided by operating system +is dealing properly with the attempt to execute + +instructions with "illegal" opcodes. + +Illegal is quotes because that just means +opcodes whose operations aren't implemented + +directly by the hardware. + +As we'll see, it's possible extend the functionality +of the hardware via software emulation. + +The action of the CPU upon encountering an +illegal instruction (sometimes referred to + +as an unimplemented user operation or UUO) +is very similar to how it processes interrupts. + +Think of illegal instructions as an interrupt +caused directly by the CPU! + +As for interrupts, the execution of the current +instruction is suspended and the control signals + +are set to values to capture PC+4 in the XP +register and set the PC to, in this case, + +0x80000004. + +Note that bit 31 of the new PC, aka the supervisor +bit, is set to 1, meaning that the OS handler + +will have access to the kernel-mode context. + +Here's some code similar to that found in +the Tiny Operating System (TinyOS), which + +you'll be experimenting with in the final +lab assignment. + +Let's do a quick walk-through of the code +executed when an illegal instruction is executed. + +Starting at location 0, we see the branches +to the handlers for the various interrupts + +and exceptions. + +In the case of an illegal instruction, the +BR(I_IllOp) in location 4 will be executed. + +Immediately following is where the OS data +structures are allocated. + +This includes space for the OS stack, UserMState +where user-mode register values are stored + +during interrupts, and the process table, +providing long-term storage for the complete + +state of each process while another process +is executing. + +When writing in assembly language, it's convenient +to define macros for operations that are used + +repeatedly. + +We can use a macro call whenever we want to +perform the action and the assembler will + +insert the body of the macro in place of the +macro call, performing a lexical substitution + +of the macro's arguments. + +Here's a macro for a two-instruction sequence +that extracts a particular field of bits from + +a 32-bit value. + +M is the bit number of the left-most bit, +N is the bit number of the right-most bit. + +Bits are numbered 0 through 31, where bit +31 is the most-significant bit, i.e., the + +one at the left end of the 32-bit binary value. + +And here are some macros that expand into +instruction sequences that save and restore + +the CPU registers to or from the UserMState +temporary storage area. + +With those macros in hand, let's see how illegal +opcodes are handled. + +Like all interrupt handlers, the first action +is to save the user-mode registers in the + +temporary storage area and initialize the +OS stack. + +Next, we fetch the illegal instruction from +the user-mode program. + +Note that the saved PC+4 value is a virtual +address in the context of the interrupted + +program. + +So we'll need to use the MMU routines to compute +the correct physical address - more about + +this on the next slide. + +Then we'll use the opcode of the illegal instruction +as an index into a table of subroutine addresses, + +one for each of the 64 possible opcodes. + +Once we have the address of the handler for +this particular illegal opcode, we JMP there + +to deal with the situation. + +Selecting a destination from a table of addresses +is called "dispatching" and the table is called + +the "dispatch table". + +If the dispatch table contains many different +entries, dispatching is much more efficient + +in time and space than a long series of compares +and branches. + +In this case, the table is indicating that +the handler for most illegal opcodes is the + +UUOError routine, +so it might have smaller and faster simply + +to test for the two illegal opcodes the OS +is going to emulate. + +Illegal opcode 1 will be used to implement +procedure calls from user-mode to the OS, + +which we call supervisor calls. + +More on this in the next segment. + +As an example of having the OS emulate an +instruction, we'll use illegal opcode 2 as + +the opcode for the SWAPREG instruction, which +we'll discuss now. + +But first just a quick look at how the OS +converts user-mode virtual addresses into + +physical addresses it can use. + +We'll build on the MMU VtoP procedure, described +in the previous lecture. + +This procedure expects as its arguments the +virtual page number and offset fields of the + +virtual address, so, +following our convention for passing arguments + +to C procedures, these are pushed onto the +stack in reverse order. + +The corresponding physical address is returned +in R0. + +We can then use the calculated physical address +to read the desired location from physical + +memory. + +Okay, back to dealing with illegal opcodes. + +Here's the handler for opcodes that are truly +illegal. + +In this case the OS uses various kernel routines +to print out a helpful error message on the + +user's console, then crashes the system! + +You may have seen these "blue screens of death" +if you run the Windows operating system, full + +of cryptic hex numbers. + +Actually, this wouldn't be the best approach +to handling an illegal opcode in a user's + +program. + +In a real operating system, it would be better +to save the state of the process in a special + +debugging file historically referred to as +a "core dump" + +and then terminate this particular process, +perhaps printing a short error message on + +the user's console to let them know what happened. + +Then later the user could start a debugging +program to examine the dump file to see where + +their bug is. + +Finally, here's the handler that will emulate +the actions of the SWAPREG instruction, after + +which program execution will resume as if +the instruction had been implemented in hardware. + +SWAPREG is an instruction that swaps the values +in the two specified registers. + +To define a new instruction, we'd first have +to let the assembler know to convert the swapreg(ra,rc) + +assembly language statement into binary. + +In this case we'll use a binary format similar +to the ADDC instruction, but setting the unused + +literal field to 0. + +The encoding for the RA and RC registers occur +in their usual fields and the opcode field + +is set to 2. + +Emulation is surprisingly simple. + +First we extract the RA and RC fields from +the binary for the swapreg instruction and + +convert those values into the appropriate +byte offsets for accessing the temporary array + +of saved register values. + +Then we use RA and RC offsets to access the +user-mode register values that have been saved + +in UserMState. + +We'll make the appropriate interchange, leaving +the updated register values in UserMState, + +where they'll be loaded into the CPU registers +upon returning from the illegal instruction + +interrupt handler. + +Finally, we'll branch to the kernel code that +restores the process state and resumes execution. + +We'll see this code in the next segment. \ No newline at end of file diff --git a/vJnXKcHUzHM.txt b/vJnXKcHUzHM.txt new file mode 100644 index 0000000000000000000000000000000000000000..e0384ede51e8707ea0b9811bed0463e6f76c2f45 --- /dev/null +++ b/vJnXKcHUzHM.txt @@ -0,0 +1,25363 @@ +align:start position:0% + +The following content is provided by MIT + + align:start position:0% +The following content is provided by MIT + + + align:start position:0% +The following content is provided by MIT +Open Courseware under a creative common + + align:start position:0% +Open Courseware under a creative common + + + align:start position:0% +Open Courseware under a creative common +license. Additional information about + + align:start position:0% +license. Additional information about + + + align:start position:0% +license. Additional information about +our license and MIT Open Courseware in + + align:start position:0% +our license and MIT Open Courseware in + + + align:start position:0% +our license and MIT Open Courseware in +general is available at ocw.mmit.edu. + + align:start position:0% + + + + align:start position:0% + +Today is the last meeting of our class + + align:start position:0% +Today is the last meeting of our class + + + align:start position:0% +Today is the last meeting of our class +on the nature of creativity. + + align:start position:0% +on the nature of creativity. + + + align:start position:0% +on the nature of creativity. +And what I wanted to do were several + + align:start position:0% +And what I wanted to do were several + + + align:start position:0% +And what I wanted to do were several +things. First, I wanted to try to pull + + align:start position:0% +things. First, I wanted to try to pull + + + align:start position:0% +things. First, I wanted to try to pull +together the various threats that we've + + align:start position:0% +together the various threats that we've + + + align:start position:0% +together the various threats that we've +been investigating. + + align:start position:0% +been investigating. + + + align:start position:0% +been investigating. +Um, second, I wanted to + + align:start position:0% +Um, second, I wanted to + + + align:start position:0% +Um, second, I wanted to +continue with a little presentation of + + align:start position:0% +continue with a little presentation of + + + align:start position:0% +continue with a little presentation of +my own uh about uh creativity in in the + + align:start position:0% +my own uh about uh creativity in in the + + + align:start position:0% +my own uh about uh creativity in in the +western world and which is related to + + align:start position:0% +western world and which is related to + + + align:start position:0% +western world and which is related to +what we were talking about last time, + + align:start position:0% +what we were talking about last time, + + + align:start position:0% +what we were talking about last time, +creativity in science and technology. + + align:start position:0% +creativity in science and technology. + + + align:start position:0% +creativity in science and technology. +But mainly I eager to hear your ideas + + align:start position:0% +But mainly I eager to hear your ideas + + + align:start position:0% +But mainly I eager to hear your ideas +about the material of the course and um + + align:start position:0% +about the material of the course and um + + + align:start position:0% +about the material of the course and um +the course itself uh together with what + + align:start position:0% +the course itself uh together with what + + + align:start position:0% +the course itself uh together with what +you have in mind for the final paper + + align:start position:0% +you have in mind for the final paper + + + align:start position:0% +you have in mind for the final paper +which is theoretically due today but for + + align:start position:0% +which is theoretically due today but for + + + align:start position:0% +which is theoretically due today but for +which I told you all you could have an + + align:start position:0% +which I told you all you could have an + + + align:start position:0% +which I told you all you could have an +extension. + + align:start position:0% +extension. + + + align:start position:0% +extension. +And so what I would like you to do is to + + align:start position:0% +And so what I would like you to do is to + + + align:start position:0% +And so what I would like you to do is to +take over and talk about what you care + + align:start position:0% +take over and talk about what you care + + + align:start position:0% +take over and talk about what you care +about which is relevant to the course. + + align:start position:0% +about which is relevant to the course. + + + align:start position:0% +about which is relevant to the course. +um particularly in relation to the paper + + align:start position:0% +um particularly in relation to the paper + + + align:start position:0% +um particularly in relation to the paper +that you're going to turn into a + + align:start position:0% +that you're going to turn into a + + + align:start position:0% +that you're going to turn into a +masterpiece when it's handed in in a few + + align:start position:0% +masterpiece when it's handed in in a few + + + align:start position:0% +masterpiece when it's handed in in a few +days. Okay. Any question of that sort or + + align:start position:0% +days. Okay. Any question of that sort or + + + align:start position:0% +days. Okay. Any question of that sort or +business that you want to attend to? Now + + align:start position:0% +business that you want to attend to? Now + + + align:start position:0% +business that you want to attend to? Now +let me start then in reminding you that + + align:start position:0% +let me start then in reminding you that + + + align:start position:0% +let me start then in reminding you that +the course started out with um ideas of + + align:start position:0% +the course started out with um ideas of + + + align:start position:0% +the course started out with um ideas of +mine that I hope and that you + + align:start position:0% +mine that I hope and that you + + + align:start position:0% +mine that I hope and that you +contributed to in fact I'll say ideas of + + align:start position:0% +contributed to in fact I'll say ideas of + + + align:start position:0% +contributed to in fact I'll say ideas of +mine but throughout but each each week + + align:start position:0% +mine but throughout but each each week + + + align:start position:0% +mine but throughout but each each week +you all contributed a great deal um + + align:start position:0% +you all contributed a great deal um + + + align:start position:0% +you all contributed a great deal um +toward the subject that uh I was + + align:start position:0% +toward the subject that uh I was + + + align:start position:0% +toward the subject that uh I was +focusing the week on and um you your + + align:start position:0% +focusing the week on and um you your + + + align:start position:0% +focusing the week on and um you your +presentation ations were very valuable. + + align:start position:0% +presentation ations were very valuable. + + + align:start position:0% +presentation ations were very valuable. +Uh the first at the beginning it was um + + align:start position:0% +Uh the first at the beginning it was um + + + align:start position:0% +Uh the first at the beginning it was um +the relationship between the spiritual + + align:start position:0% +the relationship between the spiritual + + + align:start position:0% +the relationship between the spiritual +and the creative. My idea being that uh + + align:start position:0% +and the creative. My idea being that uh + + + align:start position:0% +and the creative. My idea being that uh +western philosophy in particular has uh + + align:start position:0% +western philosophy in particular has uh + + + align:start position:0% +western philosophy in particular has uh +western thought, theology has um put the + + align:start position:0% +western thought, theology has um put the + + + align:start position:0% +western thought, theology has um put the +cart before the horse in as much as they + + align:start position:0% +cart before the horse in as much as they + + + align:start position:0% +cart before the horse in as much as they +thought that um there was a spiritual + + align:start position:0% +thought that um there was a spiritual + + + align:start position:0% +thought that um there was a spiritual +basis to creativity and consequently + + align:start position:0% +basis to creativity and consequently + + + align:start position:0% +basis to creativity and consequently +human beings could be creative by + + align:start position:0% +human beings could be creative by + + + align:start position:0% +human beings could be creative by +emulating the spiritual source. + + align:start position:0% +emulating the spiritual source. + + + align:start position:0% +emulating the spiritual source. +as against that what I argued was um it + + align:start position:0% +as against that what I argued was um it + + + align:start position:0% +as against that what I argued was um it +is the creativity in human beings + + align:start position:0% +is the creativity in human beings + + + align:start position:0% +is the creativity in human beings +wherever it comes from that's to be + + align:start position:0% +wherever it comes from that's to be + + + align:start position:0% +wherever it comes from that's to be +determined um that gives rise to our + + align:start position:0% +determined um that gives rise to our + + + align:start position:0% +determined um that gives rise to our +ideas of what is spiritual at all so + + align:start position:0% +ideas of what is spiritual at all so + + + align:start position:0% +ideas of what is spiritual at all so +that the relationship should log + + align:start position:0% +that the relationship should log + + + align:start position:0% +that the relationship should log +logically be reversed + + align:start position:0% +logically be reversed + + + align:start position:0% +logically be reversed +after that um you read my book feeling + + align:start position:0% +after that um you read my book feeling + + + align:start position:0% +after that um you read my book feeling +and imagination + + align:start position:0% +and imagination + + + align:start position:0% +and imagination +and in for the next three weeks we + + align:start position:0% +and in for the next three weeks we + + + align:start position:0% +and in for the next three weeks we +discuss + + align:start position:0% +discuss + + + align:start position:0% +discuss +different aspects of it. Uh particularly + + align:start position:0% +different aspects of it. Uh particularly + + + align:start position:0% +different aspects of it. Uh particularly +the major chapters on the four modes of + + align:start position:0% +the major chapters on the four modes of + + + align:start position:0% +the major chapters on the four modes of +approach to uh questions related to + + align:start position:0% +approach to uh questions related to + + + align:start position:0% +approach to uh questions related to +creativity. Um + + align:start position:0% +creativity. Um + + + align:start position:0% +creativity. Um +even though none of them is adequate um + + align:start position:0% +even though none of them is adequate um + + + align:start position:0% +even though none of them is adequate um +for dealing with the nature of + + align:start position:0% +for dealing with the nature of + + + align:start position:0% +for dealing with the nature of +creativity itself. It was the point of + + align:start position:0% +creativity itself. It was the point of + + + align:start position:0% +creativity itself. It was the point of +development in myself. I couldn't carry + + align:start position:0% +development in myself. I couldn't carry + + + align:start position:0% +development in myself. I couldn't carry +out that mission as well as I would have + + align:start position:0% +out that mission as well as I would have + + + align:start position:0% +out that mission as well as I would have +liked to and would still would like to + + align:start position:0% +liked to and would still would like to + + + align:start position:0% +liked to and would still would like to +that is dealing directly frontly with + + align:start position:0% +that is dealing directly frontly with + + + align:start position:0% +that is dealing directly frontly with +creativity. Um but I saw these as + + align:start position:0% +creativity. Um but I saw these as + + + align:start position:0% +creativity. Um but I saw these as +different subsidiary categories uh that + + align:start position:0% +different subsidiary categories uh that + + + align:start position:0% +different subsidiary categories uh that +are relevant to that kind of question. + + align:start position:0% +are relevant to that kind of question. + + + align:start position:0% +are relevant to that kind of question. +Um one of them was imagination. + + align:start position:0% +Um one of them was imagination. + + + align:start position:0% +Um one of them was imagination. +Uh the second is idealization. The third + + align:start position:0% +Uh the second is idealization. The third + + + align:start position:0% +Uh the second is idealization. The third +is consummation + + align:start position:0% +is consummation + + + align:start position:0% +is consummation +and the fourth is the aesthetic. Um + + align:start position:0% +and the fourth is the aesthetic. Um + + + align:start position:0% +and the fourth is the aesthetic. Um +all of these I wanted to investigate + + align:start position:0% +all of these I wanted to investigate + + + align:start position:0% +all of these I wanted to investigate +because they were humanistic modes of + + align:start position:0% +because they were humanistic modes of + + + align:start position:0% +because they were humanistic modes of +thinking. Uh science has done very + + align:start position:0% +thinking. Uh science has done very + + + align:start position:0% +thinking. Uh science has done very +little with them and it's interesting in + + align:start position:0% +little with them and it's interesting in + + + align:start position:0% +little with them and it's interesting in +in the contemporary debates about uh + + align:start position:0% +in the contemporary debates about uh + + + align:start position:0% +in the contemporary debates about uh +brain science and uh the relationship + + align:start position:0% +brain science and uh the relationship + + + align:start position:0% +brain science and uh the relationship +between body and mind um very little is + + align:start position:0% +between body and mind um very little is + + + align:start position:0% +between body and mind um very little is +said. For instance, in Minsk's book that + + align:start position:0% +said. For instance, in Minsk's book that + + + align:start position:0% +said. For instance, in Minsk's book that +we got to later, I'll get to shortly uh + + align:start position:0% +we got to later, I'll get to shortly uh + + + align:start position:0% +we got to later, I'll get to shortly uh +the emotion machine, there's not uh much + + align:start position:0% +the emotion machine, there's not uh much + + + align:start position:0% +the emotion machine, there's not uh much +that I found found very fruitful on + + align:start position:0% +that I found found very fruitful on + + + align:start position:0% +that I found found very fruitful on +those subjects. Why? Because these are + + align:start position:0% +those subjects. Why? Because these are + + + align:start position:0% +those subjects. Why? Because these are +subjects that somehow have evaded the + + align:start position:0% +subjects that somehow have evaded the + + + align:start position:0% +subjects that somehow have evaded the +scientific net too hard for science to + + align:start position:0% +scientific net too hard for science to + + + align:start position:0% +scientific net too hard for science to +deal with with the precision and the um + + align:start position:0% +deal with with the precision and the um + + + align:start position:0% +deal with with the precision and the um +replica kind of replication that defines + + align:start position:0% +replica kind of replication that defines + + + align:start position:0% +replica kind of replication that defines +the nature of science and yet native to + + align:start position:0% +the nature of science and yet native to + + + align:start position:0% +the nature of science and yet native to +the humanities. + + align:start position:0% +the humanities. + + + align:start position:0% +the humanities. +Um and I was got to them myself because + + align:start position:0% +Um and I was got to them myself because + + + align:start position:0% +Um and I was got to them myself because +I am um a humanist. My training is in + + align:start position:0% +I am um a humanist. My training is in + + + align:start position:0% +I am um a humanist. My training is in +aesthetics and humanities general + + align:start position:0% +aesthetics and humanities general + + + align:start position:0% +aesthetics and humanities general +generally. Um, but that seemed to me now + + align:start position:0% +generally. Um, but that seemed to me now + + + align:start position:0% +generally. Um, but that seemed to me now +to be the thing that cognitive studies + + align:start position:0% +to be the thing that cognitive studies + + + align:start position:0% +to be the thing that cognitive studies +ought to be able to harmonize itself + + align:start position:0% +ought to be able to harmonize itself + + + align:start position:0% +ought to be able to harmonize itself +with. It's not a substitute for + + align:start position:0% +with. It's not a substitute for + + + align:start position:0% +with. It's not a substitute for +cognitive studies or brain science or + + align:start position:0% +cognitive studies or brain science or + + + align:start position:0% +cognitive studies or brain science or +any area of the sciences. And yet it + + align:start position:0% +any area of the sciences. And yet it + + + align:start position:0% +any area of the sciences. And yet it +seems to me to be um a new approach + + align:start position:0% +seems to me to be um a new approach + + + align:start position:0% +seems to me to be um a new approach +given the the way um the history of + + align:start position:0% +given the the way um the history of + + + align:start position:0% +given the the way um the history of +ideas has gone in recent years um that + + align:start position:0% +ideas has gone in recent years um that + + + align:start position:0% +ideas has gone in recent years um that +supplements the cognitive approach and + + align:start position:0% +supplements the cognitive approach and + + + align:start position:0% +supplements the cognitive approach and +the the challenge now uh for all of us + + align:start position:0% +the the challenge now uh for all of us + + + align:start position:0% +the the challenge now uh for all of us +particularly at MIT um is to find a way + + align:start position:0% +particularly at MIT um is to find a way + + + align:start position:0% +particularly at MIT um is to find a way +of harmonizing the two. I emphasize MIT + + align:start position:0% +of harmonizing the two. I emphasize MIT + + + align:start position:0% +of harmonizing the two. I emphasize MIT +because from the very its very + + align:start position:0% +because from the very its very + + + align:start position:0% +because from the very its very +beginnings as a university uh which + + align:start position:0% +beginnings as a university uh which + + + align:start position:0% +beginnings as a university uh which +dates back to just after the second + + align:start position:0% +dates back to just after the second + + + align:start position:0% +dates back to just after the second +world war as a university uh the ideal + + align:start position:0% +world war as a university uh the ideal + + + align:start position:0% +world war as a university uh the ideal +has been to harmonize humanities and + + align:start position:0% +has been to harmonize humanities and + + + align:start position:0% +has been to harmonize humanities and +science. It's an ideal in which science + + align:start position:0% +science. It's an ideal in which science + + + align:start position:0% +science. It's an ideal in which science +has done its share and and become uh + + align:start position:0% +has done its share and and become uh + + + align:start position:0% +has done its share and and become uh +very advanced and the humanities have + + align:start position:0% +very advanced and the humanities have + + + align:start position:0% +very advanced and the humanities have +not caught up but the blame is also on + + align:start position:0% +not caught up but the blame is also on + + + align:start position:0% +not caught up but the blame is also on +part of the scientists who have never + + align:start position:0% +part of the scientists who have never + + + align:start position:0% +part of the scientists who have never +known exactly what to do about the + + align:start position:0% +known exactly what to do about the + + + align:start position:0% +known exactly what to do about the +humanities. Well, that seemed to me the + + align:start position:0% +humanities. Well, that seemed to me the + + + align:start position:0% +humanities. Well, that seemed to me the +burden of the book feeling and + + align:start position:0% +burden of the book feeling and + + + align:start position:0% +burden of the book feeling and +imagination + + align:start position:0% +imagination + + + align:start position:0% +imagination +um as a kind of extended proposal uh + + align:start position:0% +um as a kind of extended proposal uh + + + align:start position:0% +um as a kind of extended proposal uh +through the analysis of those four + + align:start position:0% +through the analysis of those four + + + align:start position:0% +through the analysis of those four +categories imagination, idealization, + + align:start position:0% +categories imagination, idealization, + + + align:start position:0% +categories imagination, idealization, +consummation and the aesthetic + + align:start position:0% +consummation and the aesthetic + + + align:start position:0% +consummation and the aesthetic +um and especially relevant to any + + align:start position:0% +um and especially relevant to any + + + align:start position:0% +um and especially relevant to any +investigation about the nature of + + align:start position:0% +investigation about the nature of + + + align:start position:0% +investigation about the nature of +creativity. + + align:start position:0% +creativity. + + + align:start position:0% +creativity. +Uh we then went on to four three weeks + + align:start position:0% +Uh we then went on to four three weeks + + + align:start position:0% +Uh we then went on to four three weeks +uh discussing um chapters in David + + align:start position:0% +uh discussing um chapters in David + + + align:start position:0% +uh discussing um chapters in David +Boom's book on creativity and uh they + + align:start position:0% +Boom's book on creativity and uh they + + + align:start position:0% +Boom's book on creativity and uh they +were um uh dealt with in parallel with + + align:start position:0% +were um uh dealt with in parallel with + + + align:start position:0% +were um uh dealt with in parallel with +chapters out of the book I'm writing now + + align:start position:0% +chapters out of the book I'm writing now + + + align:start position:0% +chapters out of the book I'm writing now +on the nature of creativity. um two of + + align:start position:0% +on the nature of creativity. um two of + + + align:start position:0% +on the nature of creativity. um two of +those weeks on uh the creative + + align:start position:0% +those weeks on uh the creative + + + align:start position:0% +those weeks on uh the creative +experience and the third the first half + + align:start position:0% +experience and the third the first half + + + align:start position:0% +experience and the third the first half +of my chapter called the creative + + align:start position:0% +of my chapter called the creative + + + align:start position:0% +of my chapter called the creative +process. In talking about the creative + + align:start position:0% +process. In talking about the creative + + + align:start position:0% +process. In talking about the creative +experience you remember I emphasized + + align:start position:0% +experience you remember I emphasized + + + align:start position:0% +experience you remember I emphasized +that the experience itself doesn't + + align:start position:0% +that the experience itself doesn't + + + align:start position:0% +that the experience itself doesn't +explain creativity even though a great + + align:start position:0% +explain creativity even though a great + + + align:start position:0% +explain creativity even though a great +many writers have assumed that. So that + + align:start position:0% +many writers have assumed that. So that + + + align:start position:0% +many writers have assumed that. So that +Kekerlay's dream and Arimedes + + align:start position:0% +Kekerlay's dream and Arimedes + + + align:start position:0% +Kekerlay's dream and Arimedes +um uh eureka experience in bathtub + + align:start position:0% +um uh eureka experience in bathtub + + + align:start position:0% +um uh eureka experience in bathtub +getting out of the bathtub um are + + align:start position:0% +getting out of the bathtub um are + + + align:start position:0% +getting out of the bathtub um are +experiences that are usually used as + + align:start position:0% +experiences that are usually used as + + + align:start position:0% +experiences that are usually used as +paradigmatic for the nature of + + align:start position:0% +paradigmatic for the nature of + + + align:start position:0% +paradigmatic for the nature of +creativity. And what I was arguing was + + align:start position:0% +creativity. And what I was arguing was + + + align:start position:0% +creativity. And what I was arguing was +that no creativity invol can involve + + align:start position:0% +that no creativity invol can involve + + + align:start position:0% +that no creativity invol can involve +that and generally does but it involves + + align:start position:0% +that and generally does but it involves + + + align:start position:0% +that and generally does but it involves +so much more that the experience should + + align:start position:0% +so much more that the experience should + + + align:start position:0% +so much more that the experience should +be given a secondary place in uh after u + + align:start position:0% +be given a secondary place in uh after u + + + align:start position:0% +be given a secondary place in uh after u +the process the nature of the creative + + align:start position:0% +the process the nature of the creative + + + align:start position:0% +the process the nature of the creative +process. U we then turned to the + + align:start position:0% +process. U we then turned to the + + + align:start position:0% +process. U we then turned to the +creative process uh both parts uh the + + align:start position:0% +creative process uh both parts uh the + + + align:start position:0% +creative process uh both parts uh the +second part overlapping what you were + + align:start position:0% +second part overlapping what you were + + + align:start position:0% +second part overlapping what you were +reading uh about in the anthology + + align:start position:0% +reading uh about in the anthology + + + align:start position:0% +reading uh about in the anthology +creativity in the arts and then I went + + align:start position:0% +creativity in the arts and then I went + + + align:start position:0% +creativity in the arts and then I went +on to the the two parts of my chapter + + align:start position:0% +on to the the two parts of my chapter + + + align:start position:0% +on to the the two parts of my chapter +called aesthetic creativity uh which is + + align:start position:0% +called aesthetic creativity uh which is + + + align:start position:0% +called aesthetic creativity uh which is +all about creativity in the arts. Um + + align:start position:0% +all about creativity in the arts. Um + + + align:start position:0% +all about creativity in the arts. Um +after that um I asked you to read a + + align:start position:0% +after that um I asked you to read a + + + align:start position:0% +after that um I asked you to read a +chapter of mine from uh my book the + + align:start position:0% +chapter of mine from uh my book the + + + align:start position:0% +chapter of mine from uh my book the +harmony of nature and spirit called + + align:start position:0% +harmony of nature and spirit called + + + align:start position:0% +harmony of nature and spirit called +aesthetic foundations of ethics and + + align:start position:0% +aesthetic foundations of ethics and + + + align:start position:0% +aesthetic foundations of ethics and +religion. Uh and we uh discussed and I + + align:start position:0% +religion. Uh and we uh discussed and I + + + align:start position:0% +religion. Uh and we uh discussed and I +read new we discussed the new chapter of + + align:start position:0% +read new we discussed the new chapter of + + + align:start position:0% +read new we discussed the new chapter of +mine called creativity and practice. The + + align:start position:0% +mine called creativity and practice. The + + + align:start position:0% +mine called creativity and practice. The +burden of that being by taking a + + align:start position:0% +burden of that being by taking a + + + align:start position:0% +burden of that being by taking a +particular um practical problem uh one + + align:start position:0% +particular um practical problem uh one + + + align:start position:0% +particular um practical problem uh one +in the field of medicine um that deals + + align:start position:0% +in the field of medicine um that deals + + + align:start position:0% +in the field of medicine um that deals +with the question of doctor assisted + + align:start position:0% +with the question of doctor assisted + + + align:start position:0% +with the question of doctor assisted +suicide. uh to that from that I opened + + align:start position:0% +suicide. uh to that from that I opened + + + align:start position:0% +suicide. uh to that from that I opened +up the analysis and claimed as I have + + align:start position:0% +up the analysis and claimed as I have + + + align:start position:0% +up the analysis and claimed as I have +elsewhere + + align:start position:0% +elsewhere + + + align:start position:0% +elsewhere +uh that all of ethics is really uh a + + align:start position:0% +uh that all of ethics is really uh a + + + align:start position:0% +uh that all of ethics is really uh a +function of creativity that no rules no + + align:start position:0% +function of creativity that no rules no + + + align:start position:0% +function of creativity that no rules no +fixed principles whether they're + + align:start position:0% +fixed principles whether they're + + + align:start position:0% +fixed principles whether they're +contient are prioristic in terms of + + align:start position:0% +contient are prioristic in terms of + + + align:start position:0% +contient are prioristic in terms of +reason and respect for the personhood of + + align:start position:0% +reason and respect for the personhood of + + + align:start position:0% +reason and respect for the personhood of +other people or utilitarian in terms of + + align:start position:0% +other people or utilitarian in terms of + + + align:start position:0% +other people or utilitarian in terms of +the greatest good for the greatest + + align:start position:0% +the greatest good for the greatest + + + align:start position:0% +the greatest good for the greatest +number. None of them are adequate for + + align:start position:0% +number. None of them are adequate for + + + align:start position:0% +number. None of them are adequate for +explaining the actual practice of + + align:start position:0% +explaining the actual practice of + + + align:start position:0% +explaining the actual practice of +ethics, how people go about making + + align:start position:0% +ethics, how people go about making + + + align:start position:0% +ethics, how people go about making +ethical decisions and uh acting in ways + + align:start position:0% +ethical decisions and uh acting in ways + + + align:start position:0% +ethical decisions and uh acting in ways +that other people will consider to be + + align:start position:0% +that other people will consider to be + + + align:start position:0% +that other people will consider to be +ethical. And and the same I claim was + + align:start position:0% +ethical. And and the same I claim was + + + align:start position:0% +ethical. And and the same I claim was +true of religion. Now, in the last two + + align:start position:0% +true of religion. Now, in the last two + + + align:start position:0% +true of religion. Now, in the last two +weeks, we've been dealing with what I + + align:start position:0% +weeks, we've been dealing with what I + + + align:start position:0% +weeks, we've been dealing with what I +call you you will recall in my + + align:start position:0% +call you you will recall in my + + + align:start position:0% +call you you will recall in my +conclusion to feeling and imagination, + + align:start position:0% +conclusion to feeling and imagination, + + + align:start position:0% +conclusion to feeling and imagination, +the religion of science. The idea that + + align:start position:0% +the religion of science. The idea that + + + align:start position:0% +the religion of science. The idea that +science uh in principle should be able + + align:start position:0% +science uh in principle should be able + + + align:start position:0% +science uh in principle should be able +to tell us through its uh rational + + align:start position:0% +to tell us through its uh rational + + + align:start position:0% +to tell us through its uh rational +procedures, it special kind of + + align:start position:0% +procedures, it special kind of + + + align:start position:0% +procedures, it special kind of +rationality, + + align:start position:0% +rationality, + + + align:start position:0% +rationality, +the truth about everything, what the + + align:start position:0% +the truth about everything, what the + + + align:start position:0% +the truth about everything, what the +world is like. There's a world out + + align:start position:0% +world is like. There's a world out + + + align:start position:0% +world is like. There's a world out +there. science investigates it in + + align:start position:0% +there. science investigates it in + + + align:start position:0% +there. science investigates it in +principle at least given enough time + + align:start position:0% +principle at least given enough time + + + align:start position:0% +principle at least given enough time +maybe not only in principle but as a + + align:start position:0% +maybe not only in principle but as a + + + align:start position:0% +maybe not only in principle but as a +kind of program for the future given + + align:start position:0% +kind of program for the future given + + + align:start position:0% +kind of program for the future given +enough um decades centuries millennia + + align:start position:0% +enough um decades centuries millennia + + + align:start position:0% +enough um decades centuries millennia +eons nobody can say but the hope is the + + align:start position:0% +eons nobody can say but the hope is the + + + align:start position:0% +eons nobody can say but the hope is the +faith is that eventually science will + + align:start position:0% +faith is that eventually science will + + + align:start position:0% +faith is that eventually science will +put all the pieces of the p of the + + align:start position:0% +put all the pieces of the p of the + + + align:start position:0% +put all the pieces of the p of the +puzzle together um jigsaw puzzle + + align:start position:0% +puzzle together um jigsaw puzzle + + + align:start position:0% +puzzle together um jigsaw puzzle +together and then um that future future + + align:start position:0% +together and then um that future future + + + align:start position:0% +together and then um that future future +generation will um will know the truth + + align:start position:0% +generation will um will know the truth + + + align:start position:0% +generation will um will know the truth +about everything, right? Uh + + align:start position:0% +about everything, right? Uh + + + align:start position:0% +about everything, right? Uh +incidentally, I forgot to mention + + align:start position:0% +incidentally, I forgot to mention + + + align:start position:0% +incidentally, I forgot to mention +something that comes into + + align:start position:0% +something that comes into + + + align:start position:0% +something that comes into +other writings of mine um about the + + align:start position:0% +other writings of mine um about the + + + align:start position:0% +other writings of mine um about the +hitchhikers g uh hitchhikers guide to + + align:start position:0% +hitchhikers g uh hitchhikers guide to + + + align:start position:0% +hitchhikers g uh hitchhikers guide to +the galaxy. What to the galaxy? Guide. + + align:start position:0% +the galaxy. What to the galaxy? Guide. + + + align:start position:0% +the galaxy. What to the galaxy? Guide. +Guide to the galaxy. Right. You remember + + align:start position:0% +Guide to the galaxy. Right. You remember + + + align:start position:0% +Guide to the galaxy. Right. You remember +at the beginning the wise men uh ask um + + align:start position:0% +at the beginning the wise men uh ask um + + + align:start position:0% +at the beginning the wise men uh ask um +um deep deep mind is it the name of the + + align:start position:0% +um deep deep mind is it the name of the + + + align:start position:0% +um deep deep mind is it the name of the +computer? Deep. Deep thought. Deep + + align:start position:0% +computer? Deep. Deep thought. Deep + + + align:start position:0% +computer? Deep. Deep thought. Deep +thought right as a parody on deep throat + + align:start position:0% +thought right as a parody on deep throat + + + align:start position:0% +thought right as a parody on deep throat +to which something very different. Um + + align:start position:0% +to which something very different. Um + + + align:start position:0% +to which something very different. Um +the um the the problem they said him is + + align:start position:0% +the um the the problem they said him is + + + align:start position:0% +the um the the problem they said him is +what is the truth about everything? Uh + + align:start position:0% +what is the truth about everything? Uh + + + align:start position:0% +what is the truth about everything? Uh +the meaning of life, the meaning of + + align:start position:0% +the meaning of life, the meaning of + + + align:start position:0% +the meaning of life, the meaning of +everything. And after many many + + align:start position:0% +everything. And after many many + + + align:start position:0% +everything. And after many many +generations + + align:start position:0% +generations + + + align:start position:0% +generations +um uh it comes up it comes up with an + + align:start position:0% +um uh it comes up it comes up with an + + + align:start position:0% +um uh it comes up it comes up with an +answer for the elders of that time + + align:start position:0% +answer for the elders of that time + + + align:start position:0% +answer for the elders of that time +who've handed hand had had who who've + + align:start position:0% +who've handed hand had had who who've + + + align:start position:0% +who've handed hand had had who who've +handed out ideas about the the problem + + align:start position:0% +handed out ideas about the the problem + + + align:start position:0% +handed out ideas about the the problem +from generation to generation and it its + + align:start position:0% +from generation to generation and it its + + + align:start position:0% +from generation to generation and it its +answer is I don't have to tell you you + + align:start position:0% +answer is I don't have to tell you you + + + align:start position:0% +answer is I don't have to tell you you +all know this right Taz it's 42 42 + + align:start position:0% +all know this right Taz it's 42 42 + + + align:start position:0% +all know this right Taz it's 42 42 +exactly that's the exact right answer + + align:start position:0% +exactly that's the exact right answer + + + align:start position:0% +exactly that's the exact right answer +and the old men are angry and say, "You + + align:start position:0% +and the old men are angry and say, "You + + + align:start position:0% +and the old men are angry and say, "You +mean all these centuries we've been + + align:start position:0% +mean all these centuries we've been + + + align:start position:0% +mean all these centuries we've been +waiting to get the answer and that's the + + align:start position:0% +waiting to get the answer and that's the + + + align:start position:0% +waiting to get the answer and that's the +best you can do?" And the computer says, + + align:start position:0% +best you can do?" And the computer says, + + + align:start position:0% +best you can do?" And the computer says, +"Well, I I checked it very carefully." + + align:start position:0% +"Well, I I checked it very carefully." + + + align:start position:0% +"Well, I I checked it very carefully." +And they're still annoyed. And and the + + align:start position:0% +And they're still annoyed. And and the + + + align:start position:0% +And they're still annoyed. And and the +the computer says, "Well, possibly you + + align:start position:0% +the computer says, "Well, possibly you + + + align:start position:0% +the computer says, "Well, possibly you +you didn't understand what you don't + + align:start position:0% +you didn't understand what you don't + + + align:start position:0% +you didn't understand what you don't +understand what the question is." And I + + align:start position:0% +understand what the question is." And I + + + align:start position:0% +understand what the question is." And I +think that's the most brilliant thing a + + align:start position:0% +think that's the most brilliant thing a + + + align:start position:0% +think that's the most brilliant thing a +computer could say. The crucial thing is + + align:start position:0% +computer could say. The crucial thing is + + + align:start position:0% +computer could say. The crucial thing is +to understand the question. That's the + + align:start position:0% +to understand the question. That's the + + + align:start position:0% +to understand the question. That's the +beginning of wisdom. That's what + + align:start position:0% +beginning of wisdom. That's what + + + align:start position:0% +beginning of wisdom. That's what +philosophy is really interested in. the + + align:start position:0% +philosophy is really interested in. the + + + align:start position:0% +philosophy is really interested in. the +giving of the answers even if they're + + align:start position:0% +giving of the answers even if they're + + + align:start position:0% +giving of the answers even if they're +purport to be scientific can be derived + + align:start position:0% +purport to be scientific can be derived + + + align:start position:0% +purport to be scientific can be derived +but the ability to understand the + + align:start position:0% +but the ability to understand the + + + align:start position:0% +but the ability to understand the +question that takes genius that I think + + align:start position:0% +question that takes genius that I think + + + align:start position:0% +question that takes genius that I think +is the highest creativity in any event + + align:start position:0% +is the highest creativity in any event + + + align:start position:0% +is the highest creativity in any event +um the u the present faith that I've + + align:start position:0% +um the u the present faith that I've + + + align:start position:0% +um the u the present faith that I've +started this little distraction on uh is + + align:start position:0% +started this little distraction on uh is + + + align:start position:0% +started this little distraction on uh is +that through brain uh studies through + + align:start position:0% +that through brain uh studies through + + + align:start position:0% +that through brain uh studies through +cognitive studies through the + + align:start position:0% +cognitive studies through the + + + align:start position:0% +cognitive studies through the +magnificent complex that MIT is now uh + + align:start position:0% +magnificent complex that MIT is now uh + + + align:start position:0% +magnificent complex that MIT is now uh +constructed. Uh in principle we should + + align:start position:0% +constructed. Uh in principle we should + + + align:start position:0% +constructed. Uh in principle we should +get to a point where all of these + + align:start position:0% +get to a point where all of these + + + align:start position:0% +get to a point where all of these +questions all of the questions about + + align:start position:0% +questions all of the questions about + + + align:start position:0% +questions all of the questions about +life and about um the world we live in + + align:start position:0% +life and about um the world we live in + + + align:start position:0% +life and about um the world we live in +about our reality the reality because + + align:start position:0% +about our reality the reality because + + + align:start position:0% +about our reality the reality because +what other one is there apart from the + + align:start position:0% +what other one is there apart from the + + + align:start position:0% +what other one is there apart from the +one we know will be solvable um and I + + align:start position:0% +one we know will be solvable um and I + + + align:start position:0% +one we know will be solvable um and I +think of that as a faith and that that + + align:start position:0% +think of that as a faith and that that + + + align:start position:0% +think of that as a faith and that that +was the argument of the conclusion to + + align:start position:0% +was the argument of the conclusion to + + + align:start position:0% +was the argument of the conclusion to +feeling and imagination. It's not that + + align:start position:0% +feeling and imagination. It's not that + + + align:start position:0% +feeling and imagination. It's not that +I'm opposed to people who have faith. + + align:start position:0% +I'm opposed to people who have faith. + + + align:start position:0% +I'm opposed to people who have faith. +What whatever the faith is, but it's + + align:start position:0% +What whatever the faith is, but it's + + + align:start position:0% +What whatever the faith is, but it's +merely a faith. And if you think that it + + align:start position:0% +merely a faith. And if you think that it + + + align:start position:0% +merely a faith. And if you think that it +itself is scientific, then I think that + + align:start position:0% +itself is scientific, then I think that + + + align:start position:0% +itself is scientific, then I think that +is a mistake that I was arguing against + + align:start position:0% +is a mistake that I was arguing against + + + align:start position:0% +is a mistake that I was arguing against +uh from my humanist philosophical point + + align:start position:0% +uh from my humanist philosophical point + + + align:start position:0% +uh from my humanist philosophical point +of view in the last chapter of that of + + align:start position:0% +of view in the last chapter of that of + + + align:start position:0% +of view in the last chapter of that of +that book. And I think it applies to um + + align:start position:0% +that book. And I think it applies to um + + + align:start position:0% +that book. And I think it applies to um +the um the the u + + align:start position:0% +the um the the u + + + align:start position:0% +the um the the u +prospect of the the new effort at MIT. + + align:start position:0% +prospect of the the new effort at MIT. + + + align:start position:0% +prospect of the the new effort at MIT. +I had when I was this is not a an + + align:start position:0% +I had when I was this is not a an + + + align:start position:0% +I had when I was this is not a an +autobiographical + + align:start position:0% +autobiographical + + + align:start position:0% +autobiographical +diversement but it's very relevant. When + + align:start position:0% +diversement but it's very relevant. When + + + align:start position:0% +diversement but it's very relevant. When +I was a an undergraduate, I had a friend + + align:start position:0% +I was a an undergraduate, I had a friend + + + align:start position:0% +I was a an undergraduate, I had a friend +in philosophy at Harvard and then we + + align:start position:0% +in philosophy at Harvard and then we + + + align:start position:0% +in philosophy at Harvard and then we +both went to graduate school in + + align:start position:0% +both went to graduate school in + + + align:start position:0% +both went to graduate school in +philosophy at Harvard and we talked a + + align:start position:0% +philosophy at Harvard and we talked a + + + align:start position:0% +philosophy at Harvard and we talked a +lot and uh the great man at that time + + align:start position:0% +lot and uh the great man at that time + + + align:start position:0% +lot and uh the great man at that time +was the philosopher and logician WV + + align:start position:0% +was the philosopher and logician WV + + + align:start position:0% +was the philosopher and logician WV +Quin. Have any of you read any of his + + align:start position:0% +Quin. Have any of you read any of his + + + align:start position:0% +Quin. Have any of you read any of his +works? In any event, he was he's he died + + align:start position:0% +works? In any event, he was he's he died + + + align:start position:0% +works? In any event, he was he's he died +maybe five years ago in a the memory of + + align:start position:0% +maybe five years ago in a the memory of + + + align:start position:0% +maybe five years ago in a the memory of +him seems to be fading already, but he + + align:start position:0% +him seems to be fading already, but he + + + align:start position:0% +him seems to be fading already, but he +was very he was the top of the heap at + + align:start position:0% +was very he was the top of the heap at + + + align:start position:0% +was very he was the top of the heap at +the time and had published an essay that + + align:start position:0% +the time and had published an essay that + + + align:start position:0% +the time and had published an essay that +we both had questions about and we my + + align:start position:0% +we both had questions about and we my + + + align:start position:0% +we both had questions about and we my +first paper was written with him and was + + align:start position:0% +first paper was written with him and was + + + align:start position:0% +first paper was written with him and was +published in the journal of philosophy + + align:start position:0% +published in the journal of philosophy + + + align:start position:0% +published in the journal of philosophy +when we were still first year graduate + + align:start position:0% +when we were still first year graduate + + + align:start position:0% +when we were still first year graduate +students and ever after that we've + + align:start position:0% +students and ever after that we've + + + align:start position:0% +students and ever after that we've +exchanged I we wrote another paper in + + align:start position:0% +exchanged I we wrote another paper in + + + align:start position:0% +exchanged I we wrote another paper in +jointly and then we've always been um + + align:start position:0% +jointly and then we've always been um + + + align:start position:0% +jointly and then we've always been um +exchanging um ideas. Now with the + + align:start position:0% +exchanging um ideas. Now with the + + + align:start position:0% +exchanging um ideas. Now with the +internet, we have a very voluminous + + align:start position:0% +internet, we have a very voluminous + + + align:start position:0% +internet, we have a very voluminous +correspondence back and forth on + + align:start position:0% +correspondence back and forth on + + + align:start position:0% +correspondence back and forth on +everything under the sun. He u uh took + + align:start position:0% +everything under the sun. He u uh took + + + align:start position:0% +everything under the sun. He u uh took +early retirement from the his + + align:start position:0% +early retirement from the his + + + align:start position:0% +early retirement from the his +professorship at the University of + + align:start position:0% +professorship at the University of + + + align:start position:0% +professorship at the University of +Maryland and moved to Florida and so we + + align:start position:0% +Maryland and moved to Florida and so we + + + align:start position:0% +Maryland and moved to Florida and so we +communicate through email mainly. Um he + + align:start position:0% +communicate through email mainly. Um he + + + align:start position:0% +communicate through email mainly. Um he +wrote a book um which is won uh a very + + align:start position:0% +wrote a book um which is won uh a very + + + align:start position:0% +wrote a book um which is won uh a very +uh prestigious award called the John + + align:start position:0% +uh prestigious award called the John + + + align:start position:0% +uh prestigious award called the John +Johnson Johnsonian prize given by the + + align:start position:0% +Johnson Johnsonian prize given by the + + + align:start position:0% +Johnson Johnsonian prize given by the +editors of the journal of philosophy and + + align:start position:0% +editors of the journal of philosophy and + + + align:start position:0% +editors of the journal of philosophy and +uh which came out maybe 20 years ago but + + align:start position:0% +uh which came out maybe 20 years ago but + + + align:start position:0% +uh which came out maybe 20 years ago but +is still remembered by analytical + + align:start position:0% +is still remembered by analytical + + + align:start position:0% +is still remembered by analytical +philosophers particularly the ones in my + + align:start position:0% +philosophers particularly the ones in my + + + align:start position:0% +philosophers particularly the ones in my +department who work along the lines that + + align:start position:0% +department who work along the lines that + + + align:start position:0% +department who work along the lines that +he had mapped out very early long before + + align:start position:0% +he had mapped out very early long before + + + align:start position:0% +he had mapped out very early long before +other people did. Uh the present uh + + align:start position:0% +other people did. Uh the present uh + + + align:start position:0% +other people did. Uh the present uh +version of that is what's called + + align:start position:0% +version of that is what's called + + + align:start position:0% +version of that is what's called +physicalism which I will explain in a + + align:start position:0% +physicalism which I will explain in a + + + align:start position:0% +physicalism which I will explain in a +moment. Um his name is Morland Perkins. + + align:start position:0% +moment. Um his name is Morland Perkins. + + + align:start position:0% +moment. Um his name is Morland Perkins. +Um and when I went to the inaugural + + align:start position:0% +Um and when I went to the inaugural + + + align:start position:0% +Um and when I went to the inaugural +proceedings at the Pikour um um center + + align:start position:0% +proceedings at the Pikour um um center + + + align:start position:0% +proceedings at the Pikour um um center +last week, I sent him uh a description + + align:start position:0% +last week, I sent him uh a description + + + align:start position:0% +last week, I sent him uh a description +of them and he he was interested. So I + + align:start position:0% +of them and he he was interested. So I + + + align:start position:0% +of them and he he was interested. So I +Xerox um what I could get uh which he + + align:start position:0% +Xerox um what I could get uh which he + + + align:start position:0% +Xerox um what I could get uh which he +could have got to off of the internet + + align:start position:0% +could have got to off of the internet + + + align:start position:0% +could have got to off of the internet +and I sent him a copy of tech talk which + + align:start position:0% +and I sent him a copy of tech talk which + + + align:start position:0% +and I sent him a copy of tech talk which +has several had several ar articles on + + align:start position:0% +has several had several ar articles on + + + align:start position:0% +has several had several ar articles on +on that in the last in the last issue. + + align:start position:0% +on that in the last in the last issue. + + + align:start position:0% +on that in the last in the last issue. +Um we in class at our last meeting you + + align:start position:0% +Um we in class at our last meeting you + + + align:start position:0% +Um we in class at our last meeting you +remember discussed the comment by one of + + align:start position:0% +remember discussed the comment by one of + + + align:start position:0% +remember discussed the comment by one of +the speakers um uh Patricia Churchland + + align:start position:0% +the speakers um uh Patricia Churchland + + + align:start position:0% +the speakers um uh Patricia Churchland +in which she said that + + align:start position:0% +in which she said that + + + align:start position:0% +in which she said that +mind uh so ideas of soul spirit mind + + align:start position:0% +mind uh so ideas of soul spirit mind + + + align:start position:0% +mind uh so ideas of soul spirit mind +consciousness + + align:start position:0% +consciousness + + + align:start position:0% +consciousness +are all simply + + align:start position:0% +are all simply + + + align:start position:0% +are all simply +illusions of the brain those were her + + align:start position:0% +illusions of the brain those were her + + + align:start position:0% +illusions of the brain those were her +words quote illusions of the brain and + + align:start position:0% +words quote illusions of the brain and + + + align:start position:0% +words quote illusions of the brain and +that's what we I question that I didn't + + align:start position:0% +that's what we I question that I didn't + + + align:start position:0% +that's what we I question that I didn't +see how that they could be illusions of + + align:start position:0% +see how that they could be illusions of + + + align:start position:0% +see how that they could be illusions of +the brain. They might somehow involve + + align:start position:0% +the brain. They might somehow involve + + + align:start position:0% +the brain. They might somehow involve +human illusions, but how could the brain + + align:start position:0% +human illusions, but how could the brain + + + align:start position:0% +human illusions, but how could the brain +have an illusion that my argument + + align:start position:0% +have an illusion that my argument + + + align:start position:0% +have an illusion that my argument +remember what I said that it's as if you + + align:start position:0% +remember what I said that it's as if you + + + align:start position:0% +remember what I said that it's as if you +thought that a hammer could have a + + align:start position:0% +thought that a hammer could have a + + + align:start position:0% +thought that a hammer could have a +headache or or + + align:start position:0% +headache or or + + + align:start position:0% +headache or or +be in a state of anxiety. Um, + + align:start position:0% +be in a state of anxiety. Um, + + + align:start position:0% +be in a state of anxiety. Um, +I discuss I discussed all that with + + align:start position:0% +I discuss I discussed all that with + + + align:start position:0% +I discuss I discussed all that with +Morland Perkins and um he he sent me + + align:start position:0% +Morland Perkins and um he he sent me + + + align:start position:0% +Morland Perkins and um he he sent me +back um an email in which he defended + + align:start position:0% +back um an email in which he defended + + + align:start position:0% +back um an email in which he defended +that view. Uh and his argument is that + + align:start position:0% +that view. Uh and his argument is that + + + align:start position:0% +that view. Uh and his argument is that +if uh what you're missing is that it's + + align:start position:0% +if uh what you're missing is that it's + + + align:start position:0% +if uh what you're missing is that it's +not a question merely of causation. It's + + align:start position:0% +not a question merely of causation. It's + + + align:start position:0% +not a question merely of causation. It's +not a question of whether the brain + + align:start position:0% +not a question of whether the brain + + + align:start position:0% +not a question of whether the brain +causes consciousness, + + align:start position:0% +causes consciousness, + + + align:start position:0% +causes consciousness, +which I don't question. I don't know who + + align:start position:0% +which I don't question. I don't know who + + + align:start position:0% +which I don't question. I don't know who +does question anymore. The question is + + align:start position:0% +does question anymore. The question is + + + align:start position:0% +does question anymore. The question is +whether consciousness + + align:start position:0% +whether consciousness + + + align:start position:0% +whether consciousness +is constituted by the brain + + align:start position:0% +is constituted by the brain + + + align:start position:0% +is constituted by the brain +um whether the two are somehow one and + + align:start position:0% +um whether the two are somehow one and + + + align:start position:0% +um whether the two are somehow one and +the same thing. uh and gave gave me a + + align:start position:0% +the same thing. uh and gave gave me a + + + align:start position:0% +the same thing. uh and gave gave me a +description. I wrote them back saying uh + + align:start position:0% +description. I wrote them back saying uh + + + align:start position:0% +description. I wrote them back saying uh +in class several of my bright students + + align:start position:0% +in class several of my bright students + + + align:start position:0% +in class several of my bright students +in this course uh held a similar view + + align:start position:0% +in this course uh held a similar view + + + align:start position:0% +in this course uh held a similar view +though they of course couldn't formulate + + align:start position:0% +though they of course couldn't formulate + + + align:start position:0% +though they of course couldn't formulate +it exact exactly or as well as as you + + align:start position:0% +it exact exactly or as well as as you + + + align:start position:0% +it exact exactly or as well as as you +can because here he is a + + align:start position:0% +can because here he is a + + + align:start position:0% +can because here he is a +an important philosopher. Um but it's a + + align:start position:0% +an important philosopher. Um but it's a + + + align:start position:0% +an important philosopher. Um but it's a +similar view to yours. And then I um I + + align:start position:0% +similar view to yours. And then I um I + + + align:start position:0% +similar view to yours. And then I um I +said to him um tell me if X constitutes + + align:start position:0% +said to him um tell me if X constitutes + + + align:start position:0% +said to him um tell me if X constitutes +Y, what does that mean? What does it + + align:start position:0% +Y, what does that mean? What does it + + + align:start position:0% +Y, what does that mean? What does it +mean for X to constitute Y? Because that + + align:start position:0% +mean for X to constitute Y? Because that + + + align:start position:0% +mean for X to constitute Y? Because that +seemed to be the view that he was + + align:start position:0% +seemed to be the view that he was + + + align:start position:0% +seemed to be the view that he was +defending. Uh I we I wasn't questioning + + align:start position:0% +defending. Uh I we I wasn't questioning + + + align:start position:0% +defending. Uh I we I wasn't questioning +um with him anymore than I did with you + + align:start position:0% +um with him anymore than I did with you + + + align:start position:0% +um with him anymore than I did with you +that the brain causes um um + + align:start position:0% +that the brain causes um um + + + align:start position:0% +that the brain causes um um +consciousness in the sense that unless + + align:start position:0% +consciousness in the sense that unless + + + align:start position:0% +consciousness in the sense that unless +there is a brain consciousness would not + + align:start position:0% +there is a brain consciousness would not + + + align:start position:0% +there is a brain consciousness would not +occur. Uh we could agree about that. uh + + align:start position:0% +occur. Uh we could agree about that. uh + + + align:start position:0% +occur. Uh we could agree about that. uh +but he and I gather you though you + + align:start position:0% +but he and I gather you though you + + + align:start position:0% +but he and I gather you though you +didn't carry it as far as he was uh were + + align:start position:0% +didn't carry it as far as he was uh were + + + align:start position:0% +didn't carry it as far as he was uh were +arguing that um the mo the consciousness + + align:start position:0% +arguing that um the mo the consciousness + + + align:start position:0% +arguing that um the mo the consciousness +is the brain con the consciousness + + align:start position:0% +is the brain con the consciousness + + + align:start position:0% +is the brain con the consciousness +is constituted by the brain or the brain + + align:start position:0% +is constituted by the brain or the brain + + + align:start position:0% +is constituted by the brain or the brain +constitutes + + align:start position:0% +constitutes + + + align:start position:0% +constitutes +no it has to be the other word I guess + + align:start position:0% +no it has to be the other word I guess + + + align:start position:0% +no it has to be the other word I guess +it was um uh the brain constitutes or + + align:start position:0% +it was um uh the brain constitutes or + + + align:start position:0% +it was um uh the brain constitutes or +could be either way a brain constitutes + + align:start position:0% +could be either way a brain constitutes + + + align:start position:0% +could be either way a brain constitutes +consciousness or consciousness is + + align:start position:0% +consciousness or consciousness is + + + align:start position:0% +consciousness or consciousness is +constituted by the brain. What does that + + align:start position:0% +constituted by the brain. What does that + + + align:start position:0% +constituted by the brain. What does that +mean? I want to read to you now + + align:start position:0% +mean? I want to read to you now + + + align:start position:0% +mean? I want to read to you now +um his email about that and um + + align:start position:0% +um his email about that and um + + + align:start position:0% +um his email about that and um +we can stop my part of the proceedings + + align:start position:0% +we can stop my part of the proceedings + + + align:start position:0% +we can stop my part of the proceedings +today with any kind of discussion about + + align:start position:0% +today with any kind of discussion about + + + align:start position:0% +today with any kind of discussion about +this that you want, but I do want to + + align:start position:0% +this that you want, but I do want to + + + align:start position:0% +this that you want, but I do want to +leave plenty of time for you + + align:start position:0% +leave plenty of time for you + + + align:start position:0% +leave plenty of time for you +talking about your papers and your ideas + + align:start position:0% +talking about your papers and your ideas + + + align:start position:0% +talking about your papers and your ideas +of everything in general. And this is + + align:start position:0% +of everything in general. And this is + + + align:start position:0% +of everything in general. And this is +Morland's reply in this context + + align:start position:0% +Morland's reply in this context + + + align:start position:0% +Morland's reply in this context +um constitutes + + align:start position:0% +um constitutes + + + align:start position:0% +um constitutes +uh is a way of signaling that there is + + align:start position:0% +uh is a way of signaling that there is + + + align:start position:0% +uh is a way of signaling that there is +nothing in the universe but physical + + align:start position:0% +nothing in the universe but physical + + + align:start position:0% +nothing in the universe but physical +stuff processes events and properties + + align:start position:0% +stuff processes events and properties + + + align:start position:0% +stuff processes events and properties +i.e + + align:start position:0% +i.e + + + align:start position:0% +i.e +that the mind, consciousness, moments, + + align:start position:0% +that the mind, consciousness, moments, + + + align:start position:0% +that the mind, consciousness, moments, +experience. Maybe it should be moments + + align:start position:0% +experience. Maybe it should be moments + + + align:start position:0% +experience. Maybe it should be moments +of experience. Um, or yeah, moments of + + align:start position:0% +of experience. Um, or yeah, moments of + + + align:start position:0% +of experience. Um, or yeah, moments of +experience, consciousness, mental + + align:start position:0% +experience, consciousness, mental + + + align:start position:0% +experience, consciousness, mental +events, + + align:start position:0% +events, + + + align:start position:0% +events, +thoughts, sensations, and so on are all + + align:start position:0% +thoughts, sensations, and so on are all + + + align:start position:0% +thoughts, sensations, and so on are all +brain structures. They are brain + + align:start position:0% +brain structures. They are brain + + + align:start position:0% +brain structures. They are brain +structures. That's the point. brain + + align:start position:0% +structures. That's the point. brain + + + align:start position:0% +structures. That's the point. brain +events, brain features, and so on + + align:start position:0% +events, brain features, and so on + + + align:start position:0% +events, brain features, and so on +through however many ways you want to + + align:start position:0% +through however many ways you want to + + + align:start position:0% +through however many ways you want to +specify that they are nothing but + + align:start position:0% +specify that they are nothing but + + + align:start position:0% +specify that they are nothing but +attributes of the human physical body. + + align:start position:0% +attributes of the human physical body. + + + align:start position:0% +attributes of the human physical body. +In other words, this expresses what used + + align:start position:0% +In other words, this expresses what used + + + align:start position:0% +In other words, this expresses what used +to be called a thoroughgoing + + align:start position:0% +to be called a thoroughgoing + + + align:start position:0% +to be called a thoroughgoing +metaphysical materialism, + + align:start position:0% +metaphysical materialism, + + + align:start position:0% +metaphysical materialism, +which is nowadays called physicalism, + + align:start position:0% +which is nowadays called physicalism, + + + align:start position:0% +which is nowadays called physicalism, +and which I would guess is the dominant + + align:start position:0% +and which I would guess is the dominant + + + align:start position:0% +and which I would guess is the dominant +belief about the nature of things among + + align:start position:0% +belief about the nature of things among + + + align:start position:0% +belief about the nature of things among +American analytical philosophers + + align:start position:0% +American analytical philosophers + + + align:start position:0% +American analytical philosophers +concerned with this sort of subject + + align:start position:0% +concerned with this sort of subject + + + align:start position:0% +concerned with this sort of subject +today. + + align:start position:0% +today. + + + align:start position:0% +today. +Though, of course, I could be wrong + + align:start position:0% +Though, of course, I could be wrong + + + align:start position:0% +Though, of course, I could be wrong +about the exact percentage. + + align:start position:0% +about the exact percentage. + + + align:start position:0% +about the exact percentage. +I personally adopted the physicalistic + + align:start position:0% +I personally adopted the physicalistic + + + align:start position:0% +I personally adopted the physicalistic +view in my doctoral thesis which uh was + + align:start position:0% +view in my doctoral thesis which uh was + + + align:start position:0% +view in my doctoral thesis which uh was +the origin of that prize-winning book of + + align:start position:0% +the origin of that prize-winning book of + + + align:start position:0% +the origin of that prize-winning book of +his that incidentally is called sens + + align:start position:0% +his that incidentally is called sens + + + align:start position:0% +his that incidentally is called sens +sensing the world + + align:start position:0% +sensing the world + + + align:start position:0% +sensing the world +um + + align:start position:0% +um + + + align:start position:0% +um +which was a physicalistic account of + + align:start position:0% +which was a physicalistic account of + + + align:start position:0% +which was a physicalistic account of +chiefly belief and secondarily drive or + + align:start position:0% +chiefly belief and secondarily drive or + + + align:start position:0% +chiefly belief and secondarily drive or +desire and tertiarily + + align:start position:0% +desire and tertiarily + + + align:start position:0% +desire and tertiarily +sense perception. Obviously, no one has + + align:start position:0% +sense perception. Obviously, no one has + + + align:start position:0% +sense perception. Obviously, no one has +proved this thesis. It's still an + + align:start position:0% +proved this thesis. It's still an + + + align:start position:0% +proved this thesis. It's still an +article of faith, if you like, as a kind + + align:start position:0% +article of faith, if you like, as a kind + + + align:start position:0% +article of faith, if you like, as a kind +of projection or prediction of how time, + + align:start position:0% +of projection or prediction of how time, + + + align:start position:0% +of projection or prediction of how time, +how over time the world will + + align:start position:0% +how over time the world will + + + align:start position:0% +how over time the world will +increasingly make itself visible as of + + align:start position:0% +increasingly make itself visible as of + + + align:start position:0% +increasingly make itself visible as of +this sort. + + align:start position:0% +this sort. + + + align:start position:0% +this sort. +So it's interesting because it talks + + align:start position:0% +So it's interesting because it talks + + + align:start position:0% +So it's interesting because it talks +about as an article of faith but it's an + + align:start position:0% +about as an article of faith but it's an + + + align:start position:0% +about as an article of faith but it's an +article of faith about discoveries that + + align:start position:0% +article of faith about discoveries that + + + align:start position:0% +article of faith about discoveries that +are not them themselves articles of + + align:start position:0% +are not them themselves articles of + + + align:start position:0% +are not them themselves articles of +faith but uh that will give concrete u + + align:start position:0% +faith but uh that will give concrete u + + + align:start position:0% +faith but uh that will give concrete u +proof scientific proof of the thesis of + + align:start position:0% +proof scientific proof of the thesis of + + + align:start position:0% +proof scientific proof of the thesis of +physicalism that he is uh defending. + + align:start position:0% +physicalism that he is uh defending. + + + align:start position:0% +physicalism that he is uh defending. +Next paragraph. However, there are + + align:start position:0% +Next paragraph. However, there are + + + align:start position:0% +Next paragraph. However, there are +certainly some very sharp and quite + + align:start position:0% +certainly some very sharp and quite + + + align:start position:0% +certainly some very sharp and quite +hard-headed analytic philosophers + + align:start position:0% +hard-headed analytic philosophers + + + align:start position:0% +hard-headed analytic philosophers +concerned with the subject who devote + + align:start position:0% +concerned with the subject who devote + + + align:start position:0% +concerned with the subject who devote +whole books still to showing that + + align:start position:0% +whole books still to showing that + + + align:start position:0% +whole books still to showing that +physicalism cannot be correct. + + align:start position:0% +physicalism cannot be correct. + + + align:start position:0% +physicalism cannot be correct. +So if your sentiments are this is me, + + align:start position:0% +So if your sentiments are this is me, + + + align:start position:0% +So if your sentiments are this is me, +you personally you not not you in + + align:start position:0% +you personally you not not you in + + + align:start position:0% +you personally you not not you in +general but me in particular. So if your + + align:start position:0% +general but me in particular. So if your + + + align:start position:0% +general but me in particular. So if your +if your own sentiments are dualistic or + + align:start position:0% +if your own sentiments are dualistic or + + + align:start position:0% +if your own sentiments are dualistic or +worse, you should feel free to continue + + align:start position:0% +worse, you should feel free to continue + + + align:start position:0% +worse, you should feel free to continue +to enjoy them with a good conscience. + + align:start position:0% + + + + align:start position:0% + +It's a wonderful it's a wonderful uh + + align:start position:0% +It's a wonderful it's a wonderful uh + + + align:start position:0% +It's a wonderful it's a wonderful uh +statement. I think now we can discuss it + + align:start position:0% +statement. I think now we can discuss it + + + align:start position:0% +statement. I think now we can discuss it +right now if any of you want to but + + align:start position:0% +right now if any of you want to but + + + align:start position:0% +right now if any of you want to but +thinking about it u I was a little taken + + align:start position:0% +thinking about it u I was a little taken + + + align:start position:0% +thinking about it u I was a little taken +aback that I should be accused of being + + align:start position:0% +aback that I should be accused of being + + + align:start position:0% +aback that I should be accused of being +a dualist because I've never thought of + + align:start position:0% +a dualist because I've never thought of + + + align:start position:0% +a dualist because I've never thought of +myself in that way and then it occurred + + align:start position:0% +myself in that way and then it occurred + + + align:start position:0% +myself in that way and then it occurred +to me + + align:start position:0% +to me + + + align:start position:0% +to me +um uh as I was walking over the bridge + + align:start position:0% +um uh as I was walking over the bridge + + + align:start position:0% +um uh as I was walking over the bridge +today thinking about the class um there + + align:start position:0% +today thinking about the class um there + + + align:start position:0% +today thinking about the class um there +are three kinds of dualists that one + + align:start position:0% +are three kinds of dualists that one + + + align:start position:0% +are three kinds of dualists that one +would have to consider. One kind of + + align:start position:0% +would have to consider. One kind of + + + align:start position:0% +would have to consider. One kind of +dualist um is uh the dualist of the + + align:start position:0% +dualist um is uh the dualist of the + + + align:start position:0% +dualist um is uh the dualist of the +traditional sort. Latin philosophy is + + align:start position:0% +traditional sort. Latin philosophy is + + + align:start position:0% +traditional sort. Latin philosophy is +supremely represented by uh Renee Deart. + + align:start position:0% +supremely represented by uh Renee Deart. + + + align:start position:0% +supremely represented by uh Renee Deart. +Decart believed that + + align:start position:0% +Decart believed that + + + align:start position:0% +Decart believed that +as a metaphysical principle there are + + align:start position:0% +as a metaphysical principle there are + + + align:start position:0% +as a metaphysical principle there are +two beings, two substances, one of which + + align:start position:0% +two beings, two substances, one of which + + + align:start position:0% +two beings, two substances, one of which +is matter, the other of which is mind. + + align:start position:0% +is matter, the other of which is mind. + + + align:start position:0% +is matter, the other of which is mind. +and that the two cannot cannot be + + align:start position:0% +and that the two cannot cannot be + + + align:start position:0% +and that the two cannot cannot be +confused one for the other and cannot be + + align:start position:0% +confused one for the other and cannot be + + + align:start position:0% +confused one for the other and cannot be +reduced to one another. Um now there are + + align:start position:0% +reduced to one another. Um now there are + + + align:start position:0% +reduced to one another. Um now there are +certain virtues for that that were + + align:start position:0% +certain virtues for that that were + + + align:start position:0% +certain virtues for that that were +capitalized on by uh Christianity and + + align:start position:0% +capitalized on by uh Christianity and + + + align:start position:0% +capitalized on by uh Christianity and +Decart was writing in a Catholic era uh + + align:start position:0% +Decart was writing in a Catholic era uh + + + align:start position:0% +Decart was writing in a Catholic era uh +when he could have got into a lot of + + align:start position:0% +when he could have got into a lot of + + + align:start position:0% +when he could have got into a lot of +trouble if he said uh things that were + + align:start position:0% +trouble if he said uh things that were + + + align:start position:0% +trouble if he said uh things that were +radically different. um Jordano Bruno, + + align:start position:0% +radically different. um Jordano Bruno, + + + align:start position:0% +radically different. um Jordano Bruno, +the great Italian um philosopher um of + + align:start position:0% +the great Italian um philosopher um of + + + align:start position:0% +the great Italian um philosopher um of +the previous century um or maybe less + + align:start position:0% +the previous century um or maybe less + + + align:start position:0% +the previous century um or maybe less +than a century from Decart um was burned + + align:start position:0% +than a century from Decart um was burned + + + align:start position:0% +than a century from Decart um was burned +at stake because he said that um that um + + align:start position:0% +at stake because he said that um that um + + + align:start position:0% +at stake because he said that um that um +um God and the world are the same. He + + align:start position:0% +um God and the world are the same. He + + + align:start position:0% +um God and the world are the same. He +was a radical pantheist. uh so uh I + + align:start position:0% +was a radical pantheist. uh so uh I + + + align:start position:0% +was a radical pantheist. uh so uh I +don't think Decart would have burned be + + align:start position:0% +don't think Decart would have burned be + + + align:start position:0% +don't think Decart would have burned be +burned the stake but he wanted to be + + align:start position:0% +burned the stake but he wanted to be + + + align:start position:0% +burned the stake but he wanted to be +acceptable to the Catholic theology that + + align:start position:0% +acceptable to the Catholic theology that + + + align:start position:0% +acceptable to the Catholic theology that +was the dominant force in French life at + + align:start position:0% +was the dominant force in French life at + + + align:start position:0% +was the dominant force in French life at +that time. Uh I mention that because um + + align:start position:0% +that time. Uh I mention that because um + + + align:start position:0% +that time. Uh I mention that because um +I can understand why religions would + + align:start position:0% +I can understand why religions would + + + align:start position:0% +I can understand why religions would +develop out of this attitude. Uh it's a + + align:start position:0% +develop out of this attitude. Uh it's a + + + align:start position:0% +develop out of this attitude. Uh it's a +very comforting one. It's one that + + align:start position:0% +very comforting one. It's one that + + + align:start position:0% +very comforting one. It's one that +speaks to the mentality of most people. + + align:start position:0% +speaks to the mentality of most people. + + + align:start position:0% +speaks to the mentality of most people. +All of us, I think, whether or not + + align:start position:0% +All of us, I think, whether or not + + + align:start position:0% +All of us, I think, whether or not +whatever whatever our religion is or if + + align:start position:0% +whatever whatever our religion is or if + + + align:start position:0% +whatever whatever our religion is or if +we even have a religion, we feel that we + + align:start position:0% +we even have a religion, we feel that we + + + align:start position:0% +we even have a religion, we feel that we +as conscious beings as ourselves are not + + align:start position:0% +as conscious beings as ourselves are not + + + align:start position:0% +as conscious beings as ourselves are not +reducible simply to our bodies. + + align:start position:0% +reducible simply to our bodies. + + + align:start position:0% +reducible simply to our bodies. +Um I Irving Singer identify with my + + align:start position:0% +Um I Irving Singer identify with my + + + align:start position:0% +Um I Irving Singer identify with my +consciousness, with my memories, with my + + align:start position:0% +consciousness, with my memories, with my + + + align:start position:0% +consciousness, with my memories, with my +experience, with my perception, my being + + align:start position:0% +experience, with my perception, my being + + + align:start position:0% +experience, with my perception, my being +here in front of you and not to what's + + align:start position:0% +here in front of you and not to what's + + + align:start position:0% +here in front of you and not to what's +happening in my uh organism, my body + + align:start position:0% +happening in my uh organism, my body + + + align:start position:0% +happening in my uh organism, my body +while I'm speaking. Um I'm not even + + align:start position:0% +while I'm speaking. Um I'm not even + + + align:start position:0% +while I'm speaking. Um I'm not even +aware of my digestive system at any time + + align:start position:0% +aware of my digestive system at any time + + + align:start position:0% +aware of my digestive system at any time +because uh it is it acts 24 hours a day + + align:start position:0% +because uh it is it acts 24 hours a day + + + align:start position:0% +because uh it is it acts 24 hours a day +uh without intruding very much into my + + align:start position:0% +uh without intruding very much into my + + + align:start position:0% +uh without intruding very much into my +consciousness. occasionally does if I + + align:start position:0% +consciousness. occasionally does if I + + + align:start position:0% +consciousness. occasionally does if I +have a belly ache but usually it's the + + align:start position:0% +have a belly ache but usually it's the + + + align:start position:0% +have a belly ache but usually it's the +body is performing its job as something + + align:start position:0% +body is performing its job as something + + + align:start position:0% +body is performing its job as something +separate from what I am aware of right + + align:start position:0% +separate from what I am aware of right + + + align:start position:0% +separate from what I am aware of right +and um I wouldn't mind if when my body + + align:start position:0% +and um I wouldn't mind if when my body + + + align:start position:0% +and um I wouldn't mind if when my body +dies which I have every reason to expect + + align:start position:0% +dies which I have every reason to expect + + + align:start position:0% +dies which I have every reason to expect +um my mind my consciousness kept on + + align:start position:0% +um my mind my consciousness kept on + + + align:start position:0% +um my mind my consciousness kept on +going + + align:start position:0% +going + + + align:start position:0% +going +um yes just as a little aside on this I + + align:start position:0% +um yes just as a little aside on this I + + + align:start position:0% +um yes just as a little aside on this I +showed an interview yesterday to my film + + align:start position:0% +showed an interview yesterday to my film + + + align:start position:0% +showed an interview yesterday to my film +class um with Ingmar Bergman who had um + + align:start position:0% +class um with Ingmar Bergman who had um + + + align:start position:0% +class um with Ingmar Bergman who had um +several of whose greatest movies are + + align:start position:0% +several of whose greatest movies are + + + align:start position:0% +several of whose greatest movies are +about religious themes and who was whose + + align:start position:0% +about religious themes and who was whose + + + align:start position:0% +about religious themes and who was whose +father was a parson in the um for the + + align:start position:0% +father was a parson in the um for the + + + align:start position:0% +father was a parson in the um for the +royal court and he was very troubled + + align:start position:0% +royal court and he was very troubled + + + align:start position:0% +royal court and he was very troubled +because he couldn't accept that faith + + align:start position:0% +because he couldn't accept that faith + + + align:start position:0% +because he couldn't accept that faith +and felt guilty and miserable and the + + align:start position:0% +and felt guilty and miserable and the + + + align:start position:0% +and felt guilty and miserable and the +movies as he says were ways of working + + align:start position:0% +movies as he says were ways of working + + + align:start position:0% +movies as he says were ways of working +out his fear of death and fear of um + + align:start position:0% +out his fear of death and fear of um + + + align:start position:0% +out his fear of death and fear of um +guilt and uh punishment because of his + + align:start position:0% +guilt and uh punishment because of his + + + align:start position:0% +guilt and uh punishment because of his +way of living. Um + + align:start position:0% +way of living. Um + + + align:start position:0% +way of living. Um +the um the in this interview made in his + + align:start position:0% +the um the in this interview made in his + + + align:start position:0% +the um the in this interview made in his +50s when he had gone through all of that + + align:start position:0% +50s when he had gone through all of that + + + align:start position:0% +50s when he had gone through all of that +he said um you know I'm happy to think + + align:start position:0% +he said um you know I'm happy to think + + + align:start position:0% +he said um you know I'm happy to think +that there is no God. I'm happy to think + + align:start position:0% +that there is no God. I'm happy to think + + + align:start position:0% +that there is no God. I'm happy to think +that when I die, it'll be like somebody + + align:start position:0% +that when I die, it'll be like somebody + + + align:start position:0% +that when I die, it'll be like somebody +turning off the light. And I would be + + align:start position:0% +turning off the light. And I would be + + + align:start position:0% +turning off the light. And I would be +very unhappy if that somebody came + + align:start position:0% +very unhappy if that somebody came + + + align:start position:0% +very unhappy if that somebody came +around and turned it back on and said, + + align:start position:0% +around and turned it back on and said, + + + align:start position:0% +around and turned it back on and said, +"You have to go here and there and be + + align:start position:0% +"You have to go here and there and be + + + align:start position:0% +"You have to go here and there and be +punished and you have guilts and we have + + align:start position:0% +punished and you have guilts and we have + + + align:start position:0% +punished and you have guilts and we have +to be cleansed and all of that." I'd + + align:start position:0% +to be cleansed and all of that." I'd + + + align:start position:0% +to be cleansed and all of that." I'd +rather I'm happy to think that this life + + align:start position:0% +rather I'm happy to think that this life + + + align:start position:0% +rather I'm happy to think that this life +is the only one. Um, well, + + align:start position:0% +is the only one. Um, well, + + + align:start position:0% +is the only one. Um, well, +I don't feel that way at all. I + + align:start position:0% +I don't feel that way at all. I + + + align:start position:0% +I don't feel that way at all. I +understand why he would because he was + + align:start position:0% +understand why he would because he was + + + align:start position:0% +understand why he would because he was +so guiltridden. I don't I I don't feel + + align:start position:0% +so guiltridden. I don't I I don't feel + + + align:start position:0% +so guiltridden. I don't I I don't feel +guiltridden. Uh what I want is to be + + align:start position:0% +guiltridden. Uh what I want is to be + + + align:start position:0% +guiltridden. Uh what I want is to be +able to go on even if it's only as a + + align:start position:0% +able to go on even if it's only as a + + + align:start position:0% +able to go on even if it's only as a +mind. I don't have that faith. But if + + align:start position:0% +mind. I don't have that faith. But if + + + align:start position:0% +mind. I don't have that faith. But if +that were turned out to be the reality, + + align:start position:0% +that were turned out to be the reality, + + + align:start position:0% +that were turned out to be the reality, +I think I I could like it very much more + + align:start position:0% +I think I I could like it very much more + + + align:start position:0% +I think I I could like it very much more +than Ingar Bergman thinks that he would + + align:start position:0% +than Ingar Bergman thinks that he would + + + align:start position:0% +than Ingar Bergman thinks that he would +like it if somebody turned on the lights + + align:start position:0% +like it if somebody turned on the lights + + + align:start position:0% +like it if somebody turned on the lights +for him. Um but all of us identify with + + align:start position:0% +for him. Um but all of us identify with + + + align:start position:0% +for him. Um but all of us identify with +our minds rather than our bodies. Uh, I + + align:start position:0% +our minds rather than our bodies. Uh, I + + + align:start position:0% +our minds rather than our bodies. Uh, I +had a friend who was dying of stomach + + align:start position:0% +had a friend who was dying of stomach + + + align:start position:0% +had a friend who was dying of stomach +cancer. Um, and I remember his saying to + + align:start position:0% +cancer. Um, and I remember his saying to + + + align:start position:0% +cancer. Um, and I remember his saying to +me, you know, there is in me a tumor as + + align:start position:0% +me, you know, there is in me a tumor as + + + align:start position:0% +me, you know, there is in me a tumor as +big as a grapefruit. What have I got to + + align:start position:0% +big as a grapefruit. What have I got to + + + align:start position:0% +big as a grapefruit. What have I got to +do with that? What what how how can I + + align:start position:0% +do with that? What what how how can I + + + align:start position:0% +do with that? What what how how can I +think of that as me? I'm totally + + align:start position:0% +think of that as me? I'm totally + + + align:start position:0% +think of that as me? I'm totally +different from that. We all And then and + + align:start position:0% +different from that. We all And then and + + + align:start position:0% +different from that. We all And then and +he knew he was going to kill him and it + + align:start position:0% +he knew he was going to kill him and it + + + align:start position:0% +he knew he was going to kill him and it +did kill him. Um, that's not what I am. + + align:start position:0% +did kill him. Um, that's not what I am. + + + align:start position:0% +did kill him. Um, that's not what I am. +Well, Deart's view about the + + align:start position:0% +Well, Deart's view about the + + + align:start position:0% +Well, Deart's view about the +relationship between mind and body makes + + align:start position:0% +relationship between mind and body makes + + + align:start position:0% +relationship between mind and body makes +sense and could could uh even possibly + + align:start position:0% +sense and could could uh even possibly + + + align:start position:0% +sense and could could uh even possibly +justify those who have the religious + + align:start position:0% +justify those who have the religious + + + align:start position:0% +justify those who have the religious +faith uh that after death the soul goes + + align:start position:0% +faith uh that after death the soul goes + + + align:start position:0% +faith uh that after death the soul goes +on and this is a good world with a good + + align:start position:0% +on and this is a good world with a good + + + align:start position:0% +on and this is a good world with a good +God and one way or another God will take + + align:start position:0% +God and one way or another God will take + + + align:start position:0% +God and one way or another God will take +care of it. That's one kind of dualism + + align:start position:0% +care of it. That's one kind of dualism + + + align:start position:0% +care of it. That's one kind of dualism +and in philosophy it's been the dominant + + align:start position:0% +and in philosophy it's been the dominant + + + align:start position:0% +and in philosophy it's been the dominant +one up until about the 20th century when + + align:start position:0% +one up until about the 20th century when + + + align:start position:0% +one up until about the 20th century when +there was great reaction against it. Um + + align:start position:0% +there was great reaction against it. Um + + + align:start position:0% +there was great reaction against it. Um +that's not the kind of dualism that + + align:start position:0% +that's not the kind of dualism that + + + align:start position:0% +that's not the kind of dualism that +applies to me because I don't have the + + align:start position:0% +applies to me because I don't have the + + + align:start position:0% +applies to me because I don't have the +metaphysical view that dayart has uh and + + align:start position:0% +metaphysical view that dayart has uh and + + + align:start position:0% +metaphysical view that dayart has uh and +don't espouse his philosophy. + + align:start position:0% +don't espouse his philosophy. + + + align:start position:0% +don't espouse his philosophy. +There's a second kind of dualism which + + align:start position:0% +There's a second kind of dualism which + + + align:start position:0% +There's a second kind of dualism which +um is um discussed by Minsky in the um + + align:start position:0% +um is um discussed by Minsky in the um + + + align:start position:0% +um is um discussed by Minsky in the um +in the um + + align:start position:0% +in the um + + + align:start position:0% +in the um +emotion machine. Uh that dualism + + align:start position:0% +emotion machine. Uh that dualism + + + align:start position:0% +emotion machine. Uh that dualism +argues um that um + + align:start position:0% +argues um that um + + + align:start position:0% +argues um that um +everything in the mind is caused by + + align:start position:0% +everything in the mind is caused by + + + align:start position:0% +everything in the mind is caused by +something happening in the brain. And + + align:start position:0% +something happening in the brain. And + + + align:start position:0% +something happening in the brain. And +therefore as Minsky says it in one place + + align:start position:0% +therefore as Minsky says it in one place + + + align:start position:0% +therefore as Minsky says it in one place +um our job in this book is to see how it + + align:start position:0% +um our job in this book is to see how it + + + align:start position:0% +um our job in this book is to see how it +is possible through what physical + + align:start position:0% +is possible through what physical + + + align:start position:0% +is possible through what physical +processes that we can investigate + + align:start position:0% +processes that we can investigate + + + align:start position:0% +processes that we can investigate +through artificial intelligence through + + align:start position:0% +through artificial intelligence through + + + align:start position:0% +through artificial intelligence through +brain brain uh science through uh + + align:start position:0% +brain brain uh science through uh + + + align:start position:0% +brain brain uh science through uh +physical uh psychology. How we can trace + + align:start position:0% +physical uh psychology. How we can trace + + + align:start position:0% +physical uh psychology. How we can trace +the origin of um our of our mental + + align:start position:0% +the origin of um our of our mental + + + align:start position:0% +the origin of um our of our mental +states to different states of the body. + + align:start position:0% +states to different states of the body. + + + align:start position:0% +states to different states of the body. +Now if by origin you mean that there is + + align:start position:0% +Now if by origin you mean that there is + + + align:start position:0% +Now if by origin you mean that there is +a causal relationship um I accept that + + align:start position:0% +a causal relationship um I accept that + + + align:start position:0% +a causal relationship um I accept that +and don't but wouldn't have thought of + + align:start position:0% +and don't but wouldn't have thought of + + + align:start position:0% +and don't but wouldn't have thought of +that as being a kind of dualism. Minsky + + align:start position:0% +that as being a kind of dualism. Minsky + + + align:start position:0% +that as being a kind of dualism. Minsky +himself offers it as a substitute for + + align:start position:0% +himself offers it as a substitute for + + + align:start position:0% +himself offers it as a substitute for +what he calls dear deart's + + align:start position:0% +what he calls dear deart's + + + align:start position:0% +what he calls dear deart's +theater of the mind as if it were + + align:start position:0% +theater of the mind as if it were + + + align:start position:0% +theater of the mind as if it were +totally independent of the body. Uh so + + align:start position:0% +totally independent of the body. Uh so + + + align:start position:0% +totally independent of the body. Uh so +that kind of dualism is not what is at + + align:start position:0% +that kind of dualism is not what is at + + + align:start position:0% +that kind of dualism is not what is at +stake in Morland Perkins rebuttal of my + + align:start position:0% +stake in Morland Perkins rebuttal of my + + + align:start position:0% +stake in Morland Perkins rebuttal of my +views. The third kind however is and + + align:start position:0% +views. The third kind however is and + + + align:start position:0% +views. The third kind however is and +it's also represented by um uh Minsky. + + align:start position:0% +it's also represented by um uh Minsky. + + + align:start position:0% +it's also represented by um uh Minsky. +Um you remember what I was calling your + + align:start position:0% +Um you remember what I was calling your + + + align:start position:0% +Um you remember what I was calling your +attention to last time uh in which + + align:start position:0% +attention to last time uh in which + + + align:start position:0% +attention to last time uh in which +Minsky says that feelings + + align:start position:0% +Minsky says that feelings + + + align:start position:0% +Minsky says that feelings +are simply uh attempts to think about + + align:start position:0% +are simply uh attempts to think about + + + align:start position:0% +are simply uh attempts to think about +something. So if the body the body has a + + align:start position:0% +something. So if the body the body has a + + + align:start position:0% +something. So if the body the body has a +problem which is how to survive under + + align:start position:0% +problem which is how to survive under + + + align:start position:0% +problem which is how to survive under +these perilous conditions of um of + + align:start position:0% +these perilous conditions of um of + + + align:start position:0% +these perilous conditions of um of +somebody pushing you to the edge of a + + align:start position:0% +somebody pushing you to the edge of a + + + align:start position:0% +somebody pushing you to the edge of a +cliff. um you're going to have a feeling + + align:start position:0% +cliff. um you're going to have a feeling + + + align:start position:0% +cliff. um you're going to have a feeling +of fear of desire to flee of whatever uh + + align:start position:0% +of fear of desire to flee of whatever uh + + + align:start position:0% +of fear of desire to flee of whatever uh +but the feeling is related to your + + align:start position:0% +but the feeling is related to your + + + align:start position:0% +but the feeling is related to your +thinking I may be killed or what should + + align:start position:0% +thinking I may be killed or what should + + + align:start position:0% +thinking I may be killed or what should +I do to escape u it's it's h the feeling + + align:start position:0% +I do to escape u it's it's h the feeling + + + align:start position:0% +I do to escape u it's it's h the feeling +is itself simply a part of the process + + align:start position:0% +is itself simply a part of the process + + + align:start position:0% +is itself simply a part of the process +of thinking + + align:start position:0% +of thinking + + + align:start position:0% +of thinking +right now that leads directly into the + + align:start position:0% +right now that leads directly into the + + + align:start position:0% +right now that leads directly into the +physicalism that Perkins and Mo's + + align:start position:0% +physicalism that Perkins and Mo's + + + align:start position:0% +physicalism that Perkins and Mo's +philosopher is if he's right and the + + align:start position:0% +philosopher is if he's right and the + + + align:start position:0% +philosopher is if he's right and the +people at the symposium uh are + + align:start position:0% +people at the symposium uh are + + + align:start position:0% +people at the symposium uh are +presupposed that the mind is simply a + + align:start position:0% +presupposed that the mind is simply a + + + align:start position:0% +presupposed that the mind is simply a +part of a physical process. My view is + + align:start position:0% +part of a physical process. My view is + + + align:start position:0% +part of a physical process. My view is +one could just as easily say the + + align:start position:0% +one could just as easily say the + + + align:start position:0% +one could just as easily say the +opposite that thinking is often uh a + + align:start position:0% +opposite that thinking is often uh a + + + align:start position:0% +opposite that thinking is often uh a +part of feeling uh that uh it isn't as + + align:start position:0% +part of feeling uh that uh it isn't as + + + align:start position:0% +part of feeling uh that uh it isn't as +if we only have we think about how to + + align:start position:0% +if we only have we think about how to + + + align:start position:0% +if we only have we think about how to +survive but also we are endowed with + + align:start position:0% +survive but also we are endowed with + + + align:start position:0% +survive but also we are endowed with +feelings which are therefore just as um + + align:start position:0% +feelings which are therefore just as um + + + align:start position:0% +feelings which are therefore just as um +highly programmed uh by nature as our + + align:start position:0% +highly programmed uh by nature as our + + + align:start position:0% +highly programmed uh by nature as our +ability to think and our uh the use of + + align:start position:0% +ability to think and our uh the use of + + + align:start position:0% +ability to think and our uh the use of +the brain for the sake of finding it + + align:start position:0% +the brain for the sake of finding it + + + align:start position:0% +the brain for the sake of finding it +means of of survival. + + align:start position:0% +means of of survival. + + + align:start position:0% +means of of survival. +we're endowed with these feelings that + + align:start position:0% +we're endowed with these feelings that + + + align:start position:0% +we're endowed with these feelings that +are useful to us and that it's the + + align:start position:0% +are useful to us and that it's the + + + align:start position:0% +are useful to us and that it's the +ignoring of of that part of the innate + + align:start position:0% +ignoring of of that part of the innate + + + align:start position:0% +ignoring of of that part of the innate +program which causes um the scientists + + align:start position:0% +program which causes um the scientists + + + align:start position:0% +program which causes um the scientists +I've been talking about and cognitive + + align:start position:0% +I've been talking about and cognitive + + + align:start position:0% +I've been talking about and cognitive +study people who do cognitive studies to + + align:start position:0% +study people who do cognitive studies to + + + align:start position:0% +study people who do cognitive studies to +shortch change the importance of + + align:start position:0% +shortch change the importance of + + + align:start position:0% +shortch change the importance of +phenomena like imagination, + + align:start position:0% +phenomena like imagination, + + + align:start position:0% +phenomena like imagination, +idealization, consummation and + + align:start position:0% +idealization, consummation and + + + align:start position:0% +idealization, consummation and +aesthetics. we're also programmed with + + align:start position:0% +aesthetics. we're also programmed with + + + align:start position:0% +aesthetics. we're also programmed with +them and they are not reducible to u + + align:start position:0% +them and they are not reducible to u + + + align:start position:0% +them and they are not reducible to u +patterns of cognition uh but rather are + + align:start position:0% +patterns of cognition uh but rather are + + + align:start position:0% +patterns of cognition uh but rather are +in interwoven with them they are in some + + align:start position:0% +in interwoven with them they are in some + + + align:start position:0% +in interwoven with them they are in some +kind of rich process so that to when + + align:start position:0% +kind of rich process so that to when + + + align:start position:0% +kind of rich process so that to when +when Minsky says what we're doing here + + align:start position:0% +when Minsky says what we're doing here + + + align:start position:0% +when Minsky says what we're doing here +is trying to to find the processes + + align:start position:0% +is trying to to find the processes + + + align:start position:0% +is trying to to find the processes +by which um the body uh contributes to + + align:start position:0% +by which um the body uh contributes to + + + align:start position:0% +by which um the body uh contributes to +our feelings things. + + align:start position:0% +our feelings things. + + + align:start position:0% +our feelings things. +I I want to say it's also a question of + + align:start position:0% +I I want to say it's also a question of + + + align:start position:0% +I I want to say it's also a question of +the processes by which our feelings + + align:start position:0% +the processes by which our feelings + + + align:start position:0% +the processes by which our feelings +interact with our thought and with other + + align:start position:0% +interact with our thought and with other + + + align:start position:0% +interact with our thought and with other +aspects that scientists uh in can easily + + align:start position:0% +aspects that scientists uh in can easily + + + align:start position:0% +aspects that scientists uh in can easily +investigate. It's just that these are + + align:start position:0% +investigate. It's just that these are + + + align:start position:0% +investigate. It's just that these are +more difficult parts of the program. And + + align:start position:0% +more difficult parts of the program. And + + + align:start position:0% +more difficult parts of the program. And +so in that sense, I both am a a dualist + + align:start position:0% +so in that sense, I both am a a dualist + + + align:start position:0% +so in that sense, I both am a a dualist +and I'm not. It's it's I don't in fact I + + align:start position:0% +and I'm not. It's it's I don't in fact I + + + align:start position:0% +and I'm not. It's it's I don't in fact I +don't like that distinction at all. Um + + align:start position:0% +don't like that distinction at all. Um + + + align:start position:0% +don't like that distinction at all. Um +the I don't want to reduce mind to body + + align:start position:0% +the I don't want to reduce mind to body + + + align:start position:0% +the I don't want to reduce mind to body +but I but I don't think that they are in + + align:start position:0% +but I but I don't think that they are in + + + align:start position:0% +but I but I don't think that they are in +principle totally independent of each + + align:start position:0% +principle totally independent of each + + + align:start position:0% +principle totally independent of each +other at least in principle as Decart + + align:start position:0% +other at least in principle as Decart + + + align:start position:0% +other at least in principle as Decart +does uh and uh thinkers and uh religious + + align:start position:0% +does uh and uh thinkers and uh religious + + + align:start position:0% +does uh and uh thinkers and uh religious +people of that sort. + + align:start position:0% +people of that sort. + + + align:start position:0% +people of that sort. +Um + + align:start position:0% +Um + + + align:start position:0% +Um +well there are various other things in + + align:start position:0% +well there are various other things in + + + align:start position:0% +well there are various other things in +Ninski which I was hoping to get to last + + align:start position:0% +Ninski which I was hoping to get to last + + + align:start position:0% +Ninski which I was hoping to get to last +time and maybe we can come back to them + + align:start position:0% +time and maybe we can come back to them + + + align:start position:0% +time and maybe we can come back to them +today but I think at this point I ought + + align:start position:0% +today but I think at this point I ought + + + align:start position:0% +today but I think at this point I ought +to turn things over to you. Um in terms + + align:start position:0% +to turn things over to you. Um in terms + + + align:start position:0% +to turn things over to you. Um in terms +of anything + + align:start position:0% +of anything + + + align:start position:0% +of anything +that you want to say in terms of where + + align:start position:0% +that you want to say in terms of where + + + align:start position:0% +that you want to say in terms of where +we were the discussion was going last + + align:start position:0% +we were the discussion was going last + + + align:start position:0% +we were the discussion was going last +time and above all and we can start with + + align:start position:0% +time and above all and we can start with + + + align:start position:0% +time and above all and we can start with +that if you want. um what you're doing + + align:start position:0% +that if you want. um what you're doing + + + align:start position:0% +that if you want. um what you're doing +in your papers to see how I can be of + + align:start position:0% +in your papers to see how I can be of + + + align:start position:0% +in your papers to see how I can be of +help to you with them. + + align:start position:0% + + + + align:start position:0% + +Do you want to start Becken? Um with my + + align:start position:0% +Do you want to start Becken? Um with my + + + align:start position:0% +Do you want to start Becken? Um with my +paper or with a general question? Well, + + align:start position:0% +paper or with a general question? Well, + + + align:start position:0% +paper or with a general question? Well, +uh you also did the euro for me. + + align:start position:0% +uh you also did the euro for me. + + + align:start position:0% +uh you also did the euro for me. +Anything of that sort that you think + + align:start position:0% +Anything of that sort that you think + + + align:start position:0% +Anything of that sort that you think +might be of interest to the class and to + + align:start position:0% +might be of interest to the class and to + + + align:start position:0% +might be of interest to the class and to +the to the subject matter we're + + align:start position:0% +the to the subject matter we're + + + align:start position:0% +the to the subject matter we're +discussing? + + align:start position:0% +discussing? + + + align:start position:0% +discussing? +Well, I have a question I'd like to ask. + + align:start position:0% +Well, I have a question I'd like to ask. + + + align:start position:0% +Well, I have a question I'd like to ask. +Sure. in in response to um dualism. + + align:start position:0% +Sure. in in response to um dualism. + + + align:start position:0% +Sure. in in response to um dualism. +That's what I was looking up online. Um + + align:start position:0% +That's what I was looking up online. Um + + + align:start position:0% +That's what I was looking up online. Um +so + + align:start position:0% +so + + + align:start position:0% +so +you got the mind brain problem and I + + align:start position:0% +you got the mind brain problem and I + + + align:start position:0% +you got the mind brain problem and I +would assume you all would agree that we + + align:start position:0% +would assume you all would agree that we + + + align:start position:0% +would assume you all would agree that we +have an intellect that is + + align:start position:0% +have an intellect that is + + + align:start position:0% +have an intellect that is +I would say above that of animals. Would + + align:start position:0% +I would say above that of animals. Would + + + align:start position:0% +I would say above that of animals. Would +you all agree? Okay. So my question is + + align:start position:0% +you all agree? Okay. So my question is + + + align:start position:0% +you all agree? Okay. So my question is +why is that? Because if you look at the + + align:start position:0% +why is that? Because if you look at the + + + align:start position:0% +why is that? Because if you look at the +function of the brain among humans and + + align:start position:0% +function of the brain among humans and + + + align:start position:0% +function of the brain among humans and +animals, the neur the physiological + + align:start position:0% +animals, the neur the physiological + + + align:start position:0% +animals, the neur the physiological +function between species who have neural + + align:start position:0% +function between species who have neural + + + align:start position:0% +function between species who have neural +cortexes is still the same. So why is it + + align:start position:0% +cortexes is still the same. So why is it + + + align:start position:0% +cortexes is still the same. So why is it +we why is it that we are able this + + align:start position:0% +we why is it that we are able this + + + align:start position:0% +we why is it that we are able this +cognitive function and they are not and + + align:start position:0% +cognitive function and they are not and + + + align:start position:0% +cognitive function and they are not and +even though and some of these animals + + align:start position:0% +even though and some of these animals + + + align:start position:0% +even though and some of these animals +have bigger brains than us. Well, we + + align:start position:0% +have bigger brains than us. Well, we + + + align:start position:0% +have bigger brains than us. Well, we +assume it's rational. It's because it's + + align:start position:0% +assume it's rational. It's because it's + + + align:start position:0% +assume it's rational. It's because it's +rational. It may not be that it may not + + align:start position:0% +rational. It may not be that it may not + + + align:start position:0% +rational. It may not be that it may not +be particularly cognitive. It might be + + align:start position:0% +be particularly cognitive. It might be + + + align:start position:0% +be particularly cognitive. It might be +emotional or social in nature that + + align:start position:0% +emotional or social in nature that + + + align:start position:0% +emotional or social in nature that +there's something you know not logical + + align:start position:0% +there's something you know not logical + + + align:start position:0% +there's something you know not logical +that we do that other animals don't do. + + align:start position:0% +that we do that other animals don't do. + + + align:start position:0% +that we do that other animals don't do. +Are you asking like why it is that we + + align:start position:0% +Are you asking like why it is that we + + + align:start position:0% +Are you asking like why it is that we +can like like make tools and like why + + align:start position:0% +can like like make tools and like why + + + align:start position:0% +can like like make tools and like why +why is it that we have this intellect + + align:start position:0% +why is it that we have this intellect + + + align:start position:0% +why is it that we have this intellect +and they do not even though the brain + + align:start position:0% +and they do not even though the brain + + + align:start position:0% +and they do not even though the brain +function is remarkably + + align:start position:0% +function is remarkably + + + align:start position:0% +function is remarkably +and especially in comparison to + + align:start position:0% +and especially in comparison to + + + align:start position:0% +and especially in comparison to +chimpanzees + + align:start position:0% +chimpanzees + + + align:start position:0% +chimpanzees +98% exactly the same. I I think that uh + + align:start position:0% +98% exactly the same. I I think that uh + + + align:start position:0% +98% exactly the same. I I think that uh +like they've done studies where it's + + align:start position:0% +like they've done studies where it's + + + align:start position:0% +like they've done studies where it's +like our brains are significantly more + + align:start position:0% +like our brains are significantly more + + + align:start position:0% +like our brains are significantly more +complex like more wrinkles or whatever + + align:start position:0% +complex like more wrinkles or whatever + + + align:start position:0% +complex like more wrinkles or whatever +and it's so just there's like there's + + align:start position:0% +and it's so just there's like there's + + + align:start position:0% +and it's so just there's like there's +more stuff going on in it than like it + + align:start position:0% +more stuff going on in it than like it + + + align:start position:0% +more stuff going on in it than like it +can be. So one point to bring out is + + align:start position:0% +can be. So one point to bring out is + + + align:start position:0% +can be. So one point to bring out is +that even a very small change in a gene + + align:start position:0% +that even a very small change in a gene + + + align:start position:0% +that even a very small change in a gene +that regulates uh the function of for + + align:start position:0% +that regulates uh the function of for + + + align:start position:0% +that regulates uh the function of for +example the brain can make a very big + + align:start position:0% +example the brain can make a very big + + + align:start position:0% +example the brain can make a very big +difference. uh a few mutations in one + + align:start position:0% +difference. uh a few mutations in one + + + align:start position:0% +difference. uh a few mutations in one +gene, I don't remember which one + + align:start position:0% +gene, I don't remember which one + + + align:start position:0% +gene, I don't remember which one +anymore, uh can basically take you from + + align:start position:0% +anymore, uh can basically take you from + + + align:start position:0% +anymore, uh can basically take you from +full language skills to being unable to + + align:start position:0% +full language skills to being unable to + + + align:start position:0% +full language skills to being unable to +speak just by a recessive mutation and + + align:start position:0% +speak just by a recessive mutation and + + + align:start position:0% +speak just by a recessive mutation and +it's in a regulator gene of the brain. + + align:start position:0% +it's in a regulator gene of the brain. + + + align:start position:0% +it's in a regulator gene of the brain. +So it's not it the you can see it as the + + align:start position:0% +So it's not it the you can see it as the + + + align:start position:0% +So it's not it the you can see it as the +body is so complex that even small + + align:start position:0% +body is so complex that even small + + + align:start position:0% +body is so complex that even small +changes in some places can have drastic + + align:start position:0% +changes in some places can have drastic + + + align:start position:0% +changes in some places can have drastic +effects. So, okay, I can buy that. But + + align:start position:0% +effects. So, okay, I can buy that. But + + + align:start position:0% +effects. So, okay, I can buy that. But +there's there's also sort of a nature + + align:start position:0% +there's there's also sort of a nature + + + align:start position:0% +there's there's also sort of a nature +nurture problem which is, you know, if + + align:start position:0% +nurture problem which is, you know, if + + + align:start position:0% +nurture problem which is, you know, if +you if you well, human infants, for + + align:start position:0% +you if you well, human infants, for + + + align:start position:0% +you if you well, human infants, for +example, are are, I think, the most + + align:start position:0% +example, are are, I think, the most + + + align:start position:0% +example, are are, I think, the most +helpless among uh primates at least, if + + align:start position:0% +helpless among uh primates at least, if + + + align:start position:0% +helpless among uh primates at least, if +not mammals in general. Uh, and it's, + + align:start position:0% +not mammals in general. Uh, and it's, + + + align:start position:0% +not mammals in general. Uh, and it's, +you know, it's through the the + + align:start position:0% +you know, it's through the the + + + align:start position:0% +you know, it's through the the +environmental stimulation, uh, through + + align:start position:0% +environmental stimulation, uh, through + + + align:start position:0% +environmental stimulation, uh, through +their development and interaction um, + + align:start position:0% +their development and interaction um, + + + align:start position:0% +their development and interaction um, +with others in society that that really + + align:start position:0% +with others in society that that really + + + align:start position:0% +with others in society that that really +grows. If you take a child and isolate + + align:start position:0% +grows. If you take a child and isolate + + + align:start position:0% +grows. If you take a child and isolate +them from that, they, you know, they + + align:start position:0% +them from that, they, you know, they + + + align:start position:0% +them from that, they, you know, they +they grow into something very different + + align:start position:0% +they grow into something very different + + + align:start position:0% +they grow into something very different +than an average person. + + align:start position:0% +than an average person. + + + align:start position:0% +than an average person. +Something that is interesting to me is + + align:start position:0% +Something that is interesting to me is + + + align:start position:0% +Something that is interesting to me is +what what would the consequences be of + + align:start position:0% +what what would the consequences be of + + + align:start position:0% +what what would the consequences be of +consciousness being an illusion? I mean, + + align:start position:0% +consciousness being an illusion? I mean, + + + align:start position:0% +consciousness being an illusion? I mean, +what if if it's an illusion of the brain + + align:start position:0% +what if if it's an illusion of the brain + + + align:start position:0% +what if if it's an illusion of the brain +as we perceive things, what what does + + align:start position:0% +as we perceive things, what what does + + + align:start position:0% +as we perceive things, what what does +that mean to us? I mean, what what what + + align:start position:0% +that mean to us? I mean, what what what + + + align:start position:0% +that mean to us? I mean, what what what +are the consequences of that? Al also + + align:start position:0% +are the consequences of that? Al also + + + align:start position:0% +are the consequences of that? Al also +your questioning from the very start was + + align:start position:0% +your questioning from the very start was + + + align:start position:0% +your questioning from the very start was +that we are above the other animals. + + align:start position:0% +that we are above the other animals. + + + align:start position:0% +that we are above the other animals. +I mean see that's that's how I don't I + + align:start position:0% +I mean see that's that's how I don't I + + + align:start position:0% +I mean see that's that's how I don't I +don't feel that. Well see that's I say I + + align:start position:0% +don't feel that. Well see that's I say I + + + align:start position:0% +don't feel that. Well see that's I say I +was trying to say that carefully. I + + align:start position:0% +was trying to say that carefully. I + + + align:start position:0% +was trying to say that carefully. I +don't mean above but at the same time + + align:start position:0% +don't mean above but at the same time + + + align:start position:0% +don't mean above but at the same time +our cognitive abilities we possess + + align:start position:0% +our cognitive abilities we possess + + + align:start position:0% +our cognitive abilities we possess +cognitive abil abilities that animals do + + align:start position:0% +cognitive abil abilities that animals do + + + align:start position:0% +cognitive abil abilities that animals do +not. Well but that seems to because + + align:start position:0% +not. Well but that seems to because + + + align:start position:0% +not. Well but that seems to because +that's the kind of species we are. + + align:start position:0% +that's the kind of species we are. + + + align:start position:0% +that's the kind of species we are. +That's true. But why is it that we + + align:start position:0% +That's true. But why is it that we + + + align:start position:0% +That's true. But why is it that we +possess these cognitive abilities and + + align:start position:0% +possess these cognitive abilities and + + + align:start position:0% +possess these cognitive abilities and +they don't? Might be because of gene + + align:start position:0% +they don't? Might be because of gene + + + align:start position:0% +they don't? Might be because of gene +mutations or it might be that uh some + + align:start position:0% +mutations or it might be that uh some + + + align:start position:0% +mutations or it might be that uh some +animals simply evolve with that as their + + align:start position:0% +animals simply evolve with that as their + + + align:start position:0% +animals simply evolve with that as their +goal so to speak. Um whereas others did + + align:start position:0% +goal so to speak. Um whereas others did + + + align:start position:0% +goal so to speak. Um whereas others did +not. Uh and one could then say + + align:start position:0% +not. Uh and one could then say + + + align:start position:0% +not. Uh and one could then say +was it a good idea? Should they have if + + align:start position:0% +was it a good idea? Should they have if + + + align:start position:0% +was it a good idea? Should they have if +they could only realize what was going + + align:start position:0% +they could only realize what was going + + + align:start position:0% +they could only realize what was going +to happen, would they have persisted? + + align:start position:0% +to happen, would they have persisted? + + + align:start position:0% +to happen, would they have persisted? +And if they persisted, maybe it was + + align:start position:0% +And if they persisted, maybe it was + + + align:start position:0% +And if they persisted, maybe it was +because they were dumb or evil or + + align:start position:0% +because they were dumb or evil or + + + align:start position:0% +because they were dumb or evil or +somehow distorted, out of touch with + + align:start position:0% +somehow distorted, out of touch with + + + align:start position:0% +somehow distorted, out of touch with +with the possibilities of life, but they + + align:start position:0% +with the possibilities of life, but they + + + align:start position:0% +with the possibilities of life, but they +always had a need to exist. Like I mean + + align:start position:0% +always had a need to exist. Like I mean + + + align:start position:0% +always had a need to exist. Like I mean +that was No, but the point is all these + + align:start position:0% +that was No, but the point is all these + + + align:start position:0% +that was No, but the point is all these +other species do continue to exist and + + align:start position:0% +other species do continue to exist and + + + align:start position:0% +other species do continue to exist and +sometimes they do very well with their + + align:start position:0% +sometimes they do very well with their + + + align:start position:0% +sometimes they do very well with their +uh lesser. That's true. But see that's + + align:start position:0% +uh lesser. That's true. But see that's + + + align:start position:0% +uh lesser. That's true. But see that's +that's the question at hand. Why is it + + align:start position:0% +that's the question at hand. Why is it + + + align:start position:0% +that's the question at hand. Why is it +that we develop these cognitive + + align:start position:0% +that we develop these cognitive + + + align:start position:0% +that we develop these cognitive +abilities and they didn't but then but + + align:start position:0% +abilities and they didn't but then but + + + align:start position:0% +abilities and they didn't but then but +then then what I'm troubled by with the + + align:start position:0% +then then what I'm troubled by with the + + + align:start position:0% +then then what I'm troubled by with the +meaning of the word why. Why in what + + align:start position:0% +meaning of the word why. Why in what + + + align:start position:0% +meaning of the word why. Why in what +sense? Could it's like saying why am I + + align:start position:0% +sense? Could it's like saying why am I + + + align:start position:0% +sense? Could it's like saying why am I +here? It's because my parents and so on. + + align:start position:0% +here? It's because my parents and so on. + + + align:start position:0% +here? It's because my parents and so on. +Well, the reason the reason I say this + + align:start position:0% +Well, the reason the reason I say this + + + align:start position:0% +Well, the reason the reason I say this +is because different species of primates + + align:start position:0% +is because different species of primates + + + align:start position:0% +is because different species of primates +through evolution, you can see great + + align:start position:0% +through evolution, you can see great + + + align:start position:0% +through evolution, you can see great +similarities, but we are the only + + align:start position:0% +similarities, but we are the only + + + align:start position:0% +similarities, but we are the only +species out of the billions on this + + align:start position:0% +species out of the billions on this + + + align:start position:0% +species out of the billions on this +planet that has this cognitive + + align:start position:0% +planet that has this cognitive + + + align:start position:0% +planet that has this cognitive +abilities. Same thing with the cats. + + align:start position:0% +abilities. Same thing with the cats. + + + align:start position:0% +abilities. Same thing with the cats. +Like all of these cats, I mean, if you + + align:start position:0% +Like all of these cats, I mean, if you + + + align:start position:0% +Like all of these cats, I mean, if you +want to go by evolution, descended from + + align:start position:0% +want to go by evolution, descended from + + + align:start position:0% +want to go by evolution, descended from +one cat, which I don't believe, but at + + align:start position:0% +one cat, which I don't believe, but at + + + align:start position:0% +one cat, which I don't believe, but at +the same time, they all possess similar + + align:start position:0% +the same time, they all possess similar + + + align:start position:0% +the same time, they all possess similar +characteristics. There is yes they have + + align:start position:0% +characteristics. There is yes they have + + + align:start position:0% +characteristics. There is yes they have +vastly vastly different abilities in + + align:start position:0% +vastly vastly different abilities in + + + align:start position:0% +vastly vastly different abilities in +terms of speed, strength, agility but in + + align:start position:0% +terms of speed, strength, agility but in + + + align:start position:0% +terms of speed, strength, agility but in +terms of primates if you consider us + + align:start position:0% +terms of primates if you consider us + + + align:start position:0% +terms of primates if you consider us +primates we the way we have developed we + + align:start position:0% +primates we the way we have developed we + + + align:start position:0% +primates we the way we have developed we +have less fur and we have these + + align:start position:0% +have less fur and we have these + + + align:start position:0% +have less fur and we have these +cognitive abilities. Why is it that we + + align:start position:0% +cognitive abilities. Why is it that we + + + align:start position:0% +cognitive abilities. Why is it that we +out of the hundreds of species or + + align:start position:0% +out of the hundreds of species or + + + align:start position:0% +out of the hundreds of species or +thousands of species were the only ones + + align:start position:0% +thousands of species were the only ones + + + align:start position:0% +thousands of species were the only ones +to develop that? But either you're + + align:start position:0% +to develop that? But either you're + + + align:start position:0% +to develop that? But either you're +asking for details of evolutionary + + align:start position:0% +asking for details of evolutionary + + + align:start position:0% +asking for details of evolutionary +biology because at the theory of + + align:start position:0% +biology because at the theory of + + + align:start position:0% +biology because at the theory of +evolution is part of the attempt to give + + align:start position:0% +evolution is part of the attempt to give + + + align:start position:0% +evolution is part of the attempt to give +a scientific answer to that question or + + align:start position:0% +a scientific answer to that question or + + + align:start position:0% +a scientific answer to that question or +else you're using the word why in you + + align:start position:0% +else you're using the word why in you + + + align:start position:0% +else you're using the word why in you +know some more metaphysical or + + align:start position:0% +know some more metaphysical or + + + align:start position:0% +know some more metaphysical or +philosophical way and if it's the latter + + align:start position:0% +philosophical way and if it's the latter + + + align:start position:0% +philosophical way and if it's the latter +um I think I then want to open up and + + align:start position:0% +um I think I then want to open up and + + + align:start position:0% +um I think I then want to open up and +say u maybe we should it's unfortunate I + + align:start position:0% +say u maybe we should it's unfortunate I + + + align:start position:0% +say u maybe we should it's unfortunate I +mean maybe it would have been so much + + align:start position:0% +mean maybe it would have been so much + + + align:start position:0% +mean maybe it would have been so much +better if you add up all the goods in In + + align:start position:0% +better if you add up all the goods in In + + + align:start position:0% +better if you add up all the goods in In +this world, all the happiness, pleasure, + + align:start position:0% +this world, all the happiness, pleasure, + + + align:start position:0% +this world, all the happiness, pleasure, +all the positive things that we + + align:start position:0% +all the positive things that we + + + align:start position:0% +all the positive things that we +ourselves having evolved the way we have + + align:start position:0% +ourselves having evolved the way we have + + + align:start position:0% +ourselves having evolved the way we have +looking back over everything value. + + align:start position:0% +looking back over everything value. + + + align:start position:0% +looking back over everything value. +There may be more suffering + + align:start position:0% +There may be more suffering + + + align:start position:0% +There may be more suffering +than there is well-being. Think of all + + align:start position:0% +than there is well-being. Think of all + + + align:start position:0% +than there is well-being. Think of all +the animals that are slaughtered. All + + align:start position:0% +the animals that are slaughtered. All + + + align:start position:0% +the animals that are slaughtered. All +these millions and millions of people + + align:start position:0% +these millions and millions of people + + + align:start position:0% +these millions and millions of people +who's with these higher intellects who + + align:start position:0% +who's with these higher intellects who + + + align:start position:0% +who's with these higher intellects who +are killed for no good reason except + + align:start position:0% +are killed for no good reason except + + + align:start position:0% +are killed for no good reason except +because they belong uh in the wrong + + align:start position:0% +because they belong uh in the wrong + + + align:start position:0% +because they belong uh in the wrong +place at the wrong time with the wrong + + align:start position:0% +place at the wrong time with the wrong + + + align:start position:0% +place at the wrong time with the wrong +religion at the wrong time or the their + + align:start position:0% +religion at the wrong time or the their + + + align:start position:0% +religion at the wrong time or the their +race or whatever reason. All of this + + align:start position:0% +race or whatever reason. All of this + + + align:start position:0% +race or whatever reason. All of this +misery that we tend to ignore because + + align:start position:0% +misery that we tend to ignore because + + + align:start position:0% +misery that we tend to ignore because +it's just too painful to face up to + + align:start position:0% +it's just too painful to face up to + + + align:start position:0% +it's just too painful to face up to +them. + + align:start position:0% +them. + + + align:start position:0% +them. +In that sense, one could say why why + + align:start position:0% +In that sense, one could say why why + + + align:start position:0% +In that sense, one could say why why +couldn't we just be comfortable like + + align:start position:0% +couldn't we just be comfortable like + + + align:start position:0% +couldn't we just be comfortable like +pussycats and and domestic dogs? Why did + + align:start position:0% +pussycats and and domestic dogs? Why did + + + align:start position:0% +pussycats and and domestic dogs? Why did +we why do we need this extra intellect? + + align:start position:0% +we why do we need this extra intellect? + + + align:start position:0% +we why do we need this extra intellect? +Why Hamlet has it and a lot of freedom? + + align:start position:0% +Why Hamlet has it and a lot of freedom? + + + align:start position:0% +Why Hamlet has it and a lot of freedom? +Um you see so in that sense what you're + + align:start position:0% +Um you see so in that sense what you're + + + align:start position:0% +Um you see so in that sense what you're +asking now is a value question rather + + align:start position:0% +asking now is a value question rather + + + align:start position:0% +asking now is a value question rather +than a scientific one. If it's a + + align:start position:0% +than a scientific one. If it's a + + + align:start position:0% +than a scientific one. If it's a +scientific one, the answer is given by + + align:start position:0% +scientific one, the answer is given by + + + align:start position:0% +scientific one, the answer is given by +uh theories like the theory of + + align:start position:0% +uh theories like the theory of + + + align:start position:0% +uh theories like the theory of +evolution. If it's philosophical, + + align:start position:0% +evolution. If it's philosophical, + + + align:start position:0% +evolution. If it's philosophical, +then I myself say um it could all it + + align:start position:0% +then I myself say um it could all it + + + align:start position:0% +then I myself say um it could all it +could all have been a great big mistake. + + align:start position:0% +could all have been a great big mistake. + + + align:start position:0% +could all have been a great big mistake. +And that thinkers who said um the world + + align:start position:0% +And that thinkers who said um the world + + + align:start position:0% +And that thinkers who said um the world +was created by a cruel, angry, hateful + + align:start position:0% +was created by a cruel, angry, hateful + + + align:start position:0% +was created by a cruel, angry, hateful +god may very well be right. there's that + + align:start position:0% +god may very well be right. there's that + + + align:start position:0% +god may very well be right. there's that +much misery in the world that um one + + align:start position:0% +much misery in the world that um one + + + align:start position:0% +much misery in the world that um one +feels wouldn't exist if we didn't have + + align:start position:0% +feels wouldn't exist if we didn't have + + + align:start position:0% +feels wouldn't exist if we didn't have +these big intellects and and or the + + align:start position:0% +these big intellects and and or the + + + align:start position:0% +these big intellects and and or the +solution is yes u maybe that's true but + + align:start position:0% +solution is yes u maybe that's true but + + + align:start position:0% +solution is yes u maybe that's true but +that's how things are the we came came + + align:start position:0% +that's how things are the we came came + + + align:start position:0% +that's how things are the we came came +out of galactic dust and somehow it + + align:start position:0% +out of galactic dust and somehow it + + + align:start position:0% +out of galactic dust and somehow it +evolved into one species ourselves that + + align:start position:0% +evolved into one species ourselves that + + + align:start position:0% +evolved into one species ourselves that +then could conquer the world and in fact + + align:start position:0% +then could conquer the world and in fact + + + align:start position:0% +then could conquer the world and in fact +that's the reason why we have the + + align:start position:0% +that's the reason why we have the + + + align:start position:0% +that's the reason why we have the +intellect we do because it gives us that + + align:start position:0% +intellect we do because it gives us that + + + align:start position:0% +intellect we do because it gives us that +ability ability to conquer the world. + + align:start position:0% +ability ability to conquer the world. + + + align:start position:0% +ability ability to conquer the world. +You know, the insects still the last + + align:start position:0% +You know, the insects still the last + + + align:start position:0% +You know, the insects still the last +word isn't in. The jury is still out + + align:start position:0% +word isn't in. The jury is still out + + + align:start position:0% +word isn't in. The jury is still out +because the insects may eventually take + + align:start position:0% +because the insects may eventually take + + + align:start position:0% +because the insects may eventually take +over. But a short of that, that explains + + align:start position:0% +over. But a short of that, that explains + + + align:start position:0% +over. But a short of that, that explains +and why we have our intellect and one + + align:start position:0% +and why we have our intellect and one + + + align:start position:0% +and why we have our intellect and one +could say it's a pity. Who needed that? + + align:start position:0% +could say it's a pity. Who needed that? + + + align:start position:0% +could say it's a pity. Who needed that? +Who in the universe needs that? Now from + + align:start position:0% +Who in the universe needs that? Now from + + + align:start position:0% +Who in the universe needs that? Now from +the point of view of an individual who's + + align:start position:0% +the point of view of an individual who's + + + align:start position:0% +the point of view of an individual who's +interested in his own welfare + + align:start position:0% +interested in his own welfare + + + align:start position:0% +interested in his own welfare +and let's say he's an American bourgeoa + + align:start position:0% +and let's say he's an American bourgeoa + + + align:start position:0% +and let's say he's an American bourgeoa +who's been very lucky to have survived + + align:start position:0% +who's been very lucky to have survived + + + align:start position:0% +who's been very lucky to have survived +as long as he has and um sort of enjoys + + align:start position:0% +as long as he has and um sort of enjoys + + + align:start position:0% +as long as he has and um sort of enjoys +life. In other words, me um the question + + align:start position:0% +life. In other words, me um the question + + + align:start position:0% +life. In other words, me um the question +doesn't bother me very much. Well, you + + align:start position:0% +doesn't bother me very much. Well, you + + + align:start position:0% +doesn't bother me very much. Well, you +mean why? Well, I I I'm happy enough. I + + align:start position:0% +mean why? Well, I I I'm happy enough. I + + + align:start position:0% +mean why? Well, I I I'm happy enough. I +just want to live forever. + + align:start position:0% +just want to live forever. + + + align:start position:0% +just want to live forever. +um I'm not happy with the idea of giving + + align:start position:0% +um I'm not happy with the idea of giving + + + align:start position:0% +um I'm not happy with the idea of giving +up all these good things. But that's a + + align:start position:0% +up all these good things. But that's a + + + align:start position:0% +up all these good things. But that's a +different kind of attitude and different + + align:start position:0% +different kind of attitude and different + + + align:start position:0% +different kind of attitude and different +kind of question. If it's the kind that + + align:start position:0% +kind of question. If it's the kind that + + + align:start position:0% +kind of question. If it's the kind that +you were asking, then we're back to that + + align:start position:0% +you were asking, then we're back to that + + + align:start position:0% +you were asking, then we're back to that +same problem. + + align:start position:0% + + + + align:start position:0% + +I think the irony is that you're asking + + align:start position:0% +I think the irony is that you're asking + + + align:start position:0% +I think the irony is that you're asking +a question that requires us to + + align:start position:0% +a question that requires us to + + + align:start position:0% +a question that requires us to +understand our own brains. Yeah, that + + align:start position:0% +understand our own brains. Yeah, that + + + align:start position:0% +understand our own brains. Yeah, that +was actually I don't recall who said + + align:start position:0% +was actually I don't recall who said + + + align:start position:0% +was actually I don't recall who said +this statement but um + + align:start position:0% +this statement but um + + + align:start position:0% +this statement but um +the statement was the brain or the mind + + align:start position:0% +the statement was the brain or the mind + + + align:start position:0% +the statement was the brain or the mind +is the universe trying to understand + + align:start position:0% +is the universe trying to understand + + + align:start position:0% +is the universe trying to understand +itself. So just wanted to throw that out + + align:start position:0% +itself. So just wanted to throw that out + + + align:start position:0% +itself. So just wanted to throw that out +there. Well, George Bernard Saw said + + align:start position:0% +there. Well, George Bernard Saw said + + + align:start position:0% +there. Well, George Bernard Saw said +that the human brain is the attempt on + + align:start position:0% +that the human brain is the attempt on + + + align:start position:0% +that the human brain is the attempt on +the part of the universe to understand + + align:start position:0% +the part of the universe to understand + + + align:start position:0% +the part of the universe to understand +itself. + + align:start position:0% +itself. + + + align:start position:0% +itself. +That that we well you get the idea that + + align:start position:0% +That that we well you get the idea that + + + align:start position:0% +That that we well you get the idea that +we struggling for knowledge are the + + align:start position:0% +we struggling for knowledge are the + + + align:start position:0% +we struggling for knowledge are the +universe trying to make sense out of + + align:start position:0% +universe trying to make sense out of + + + align:start position:0% +universe trying to make sense out of +itself. But it was also in some of David + + align:start position:0% +itself. But it was also in some of David + + + align:start position:0% +itself. But it was also in some of David +Bow's writing when I was researching my + + align:start position:0% +Bow's writing when I was researching my + + + align:start position:0% +Bow's writing when I was researching my +first paper with his whole theory of + + align:start position:0% +first paper with his whole theory of + + + align:start position:0% +first paper with his whole theory of +infolding and the fact that the brain + + align:start position:0% +infolding and the fact that the brain + + + align:start position:0% +infolding and the fact that the brain +can't possibly actually understand + + align:start position:0% +can't possibly actually understand + + + align:start position:0% +can't possibly actually understand +anything cuz it is as much a part of the + + align:start position:0% +anything cuz it is as much a part of the + + + align:start position:0% +anything cuz it is as much a part of the +as anything else is as if without us. + + align:start position:0% +as anything else is as if without us. + + + align:start position:0% +as anything else is as if without us. +Yeah. Like well just that we are a part + + align:start position:0% +Yeah. Like well just that we are a part + + + align:start position:0% +Yeah. Like well just that we are a part +of it and therefore we cannot ever + + align:start position:0% +of it and therefore we cannot ever + + + align:start position:0% +of it and therefore we cannot ever +understand ourselves because it's + + align:start position:0% +understand ourselves because it's + + + align:start position:0% +understand ourselves because it's +trying. Yeah. It's it's circular. Yeah. + + align:start position:0% +trying. Yeah. It's it's circular. Yeah. + + + align:start position:0% +trying. Yeah. It's it's circular. Yeah. +The universe trying to understand. My + + align:start position:0% +The universe trying to understand. My + + + align:start position:0% +The universe trying to understand. My +view is even more radical and that is + + align:start position:0% +view is even more radical and that is + + + align:start position:0% +view is even more radical and that is +that I have none of the scientific faith + + align:start position:0% +that I have none of the scientific faith + + + align:start position:0% +that I have none of the scientific faith +that we can eventually understand + + align:start position:0% +that we can eventually understand + + + align:start position:0% +that we can eventually understand +everything else. + + align:start position:0% +everything else. + + + align:start position:0% +everything else. +But theoretically yourself as well + + align:start position:0% +But theoretically yourself as well + + + align:start position:0% +But theoretically yourself as well +because you are the universe. Um but um + + align:start position:0% +because you are the universe. Um but um + + + align:start position:0% +because you are the universe. Um but um +I I it's not just that we can't + + align:start position:0% +I I it's not just that we can't + + + align:start position:0% +I I it's not just that we can't +understand ourselves. I haven't any + + align:start position:0% +understand ourselves. I haven't any + + + align:start position:0% +understand ourselves. I haven't any +faith we can understand everything about + + align:start position:0% +faith we can understand everything about + + + align:start position:0% +faith we can understand everything about +everything else. + + align:start position:0% +everything else. + + + align:start position:0% +everything else. +So one thing I or or whether would be a + + align:start position:0% +So one thing I or or whether would be a + + + align:start position:0% +So one thing I or or whether would be a +good idea. Would would that make you + + align:start position:0% +good idea. Would would that make you + + + align:start position:0% +good idea. Would would that make you +happy? I don't know. Yeah. I think the + + align:start position:0% +happy? I don't know. Yeah. I think the + + + align:start position:0% +happy? I don't know. Yeah. I think the +uh example of Hamlet is that people who + + align:start position:0% +uh example of Hamlet is that people who + + + align:start position:0% +uh example of Hamlet is that people who +who think too much um often make + + align:start position:0% +who think too much um often make + + + align:start position:0% +who think too much um often make +themselves miserable and that the only + + align:start position:0% +themselves miserable and that the only + + + align:start position:0% +themselves miserable and that the only +happy ones are the ones who are very + + align:start position:0% +happy ones are the ones who are very + + + align:start position:0% +happy ones are the ones who are very +limited. + + align:start position:0% +limited. + + + align:start position:0% +limited. +Wow. + + align:start position:0% +Wow. + + + align:start position:0% +Wow. +One thing I ran across um in a book + + align:start position:0% +One thing I ran across um in a book + + + align:start position:0% +One thing I ran across um in a book +discussing entropy in art uh was the + + align:start position:0% +discussing entropy in art uh was the + + + align:start position:0% +discussing entropy in art uh was the +statement that creativity has a function + + align:start position:0% +statement that creativity has a function + + + align:start position:0% +statement that creativity has a function +and its function is to maintain a + + align:start position:0% +and its function is to maintain a + + + align:start position:0% +and its function is to maintain a +balance or homeostasis for a person in + + align:start position:0% +balance or homeostasis for a person in + + + align:start position:0% +balance or homeostasis for a person in +response to the destruction caused by + + align:start position:0% +response to the destruction caused by + + + align:start position:0% +response to the destruction caused by +entropy around them. What do you guys + + align:start position:0% +entropy around them. What do you guys + + + align:start position:0% +entropy around them. What do you guys +make of that? Do you think like do do + + align:start position:0% +make of that? Do you think like do do + + + align:start position:0% +make of that? Do you think like do do +you think creativity has a function and + + align:start position:0% +you think creativity has a function and + + + align:start position:0% +you think creativity has a function and +that's to it it's for the individual to + + align:start position:0% +that's to it it's for the individual to + + + align:start position:0% +that's to it it's for the individual to +respond to the random forces pushing + + align:start position:0% +respond to the random forces pushing + + + align:start position:0% +respond to the random forces pushing +against him or her in life. + + align:start position:0% + + + + align:start position:0% + +It's an interesting idea. Who who + + align:start position:0% +It's an interesting idea. Who who + + + align:start position:0% +It's an interesting idea. Who who +proposed that? I don't remember. It's in + + align:start position:0% +proposed that? I don't remember. It's in + + + align:start position:0% +proposed that? I don't remember. It's in +a book called Entropy and Art. I know + + align:start position:0% +a book called Entropy and Art. I know + + + align:start position:0% +a book called Entropy and Art. I know +that much. Do does it come into your + + align:start position:0% +that much. Do does it come into your + + + align:start position:0% +that much. Do does it come into your +paper? Uh possibly. + + align:start position:0% +paper? Uh possibly. + + + align:start position:0% +paper? Uh possibly. +I it started out great and then I didn't + + align:start position:0% +I it started out great and then I didn't + + + align:start position:0% +I it started out great and then I didn't +like the second half of it. So So you're + + align:start position:0% +like the second half of it. So So you're + + + align:start position:0% +like the second half of it. So So you're +working on something else related. Yes. + + align:start position:0% +working on something else related. Yes. + + + align:start position:0% +working on something else related. Yes. +Okay. Um + + align:start position:0% +Okay. Um + + + align:start position:0% +Okay. Um +Arnard + + align:start position:0% +Arnard + + + align:start position:0% +Arnard +possibly. I I + + align:start position:0% +possibly. I I + + + align:start position:0% +possibly. I I +What did you find? Actually, I just + + align:start position:0% +What did you find? Actually, I just + + + align:start position:0% +What did you find? Actually, I just +found an essay, not a book. Never mind. + + align:start position:0% +found an essay, not a book. Never mind. + + + align:start position:0% +found an essay, not a book. Never mind. +It Well, it's like 50 pages long. Yeah, + + align:start position:0% +It Well, it's like 50 pages long. Yeah, + + + align:start position:0% +It Well, it's like 50 pages long. Yeah, +it's an essay. Okay. uh Arnheim + + align:start position:0% +it's an essay. Okay. uh Arnheim + + + align:start position:0% +it's an essay. Okay. uh Arnheim +Arnheim he's a very important uh + + align:start position:0% +Arnheim he's a very important uh + + + align:start position:0% +Arnheim he's a very important uh +aesthetician who wrote a great deal + + align:start position:0% +aesthetician who wrote a great deal + + + align:start position:0% +aesthetician who wrote a great deal +particularly at the beginning about the + + align:start position:0% +particularly at the beginning about the + + + align:start position:0% +particularly at the beginning about the +aesthetics of film he's one of the you + + align:start position:0% +aesthetics of film he's one of the you + + + align:start position:0% +aesthetics of film he's one of the you +know icons of the development of film + + align:start position:0% +know icons of the development of film + + + align:start position:0% +know icons of the development of film +studies um and I think he died in the + + align:start position:0% +studies um and I think he died in the + + + align:start position:0% +studies um and I think he died in the +70s or 80s not too long ago + + align:start position:0% +70s or 80s not too long ago + + + align:start position:0% +70s or 80s not too long ago +Rudolfph Orinheim that's very + + align:start position:0% +Rudolfph Orinheim that's very + + + align:start position:0% +Rudolfph Orinheim that's very +interesting what's the book itself. + + align:start position:0% +interesting what's the book itself. + + + align:start position:0% +interesting what's the book itself. +Uh, Entropy and Art. + + align:start position:0% +Uh, Entropy and Art. + + + align:start position:0% +Uh, Entropy and Art. +And the essay is Entropy and Art? Yes. + + align:start position:0% +And the essay is Entropy and Art? Yes. + + + align:start position:0% +And the essay is Entropy and Art? Yes. +And he wrote the whole book or it's an + + align:start position:0% +And he wrote the whole book or it's an + + + align:start position:0% +And he wrote the whole book or it's an +anthology? + + align:start position:0% +anthology? + + + align:start position:0% +anthology? +It's a It's a 60page essay that he + + align:start position:0% +It's a It's a 60page essay that he + + + align:start position:0% +It's a It's a 60page essay that he +wrote. Uh, in his own book? Yes. Oh, + + align:start position:0% +wrote. Uh, in his own book? Yes. Oh, + + + align:start position:0% +wrote. Uh, in his own book? Yes. Oh, +okay. Yeah. And it looks like the entire + + align:start position:0% +okay. Yeah. And it looks like the entire + + + align:start position:0% +okay. Yeah. And it looks like the entire +thing is online. Cool. + + align:start position:0% +thing is online. Cool. + + + align:start position:0% +thing is online. Cool. +Yeah, it is. Okay. Well, that's Anything + + align:start position:0% +Yeah, it is. Okay. Well, that's Anything + + + align:start position:0% +Yeah, it is. Okay. Well, that's Anything +more you want to say about that? Well, I + + align:start position:0% +more you want to say about that? Well, I + + + align:start position:0% +more you want to say about that? Well, I +I just wanted to see what people think + + align:start position:0% +I just wanted to see what people think + + + align:start position:0% +I just wanted to see what people think +of the idea that uh I mean what what I'm + + align:start position:0% +of the idea that uh I mean what what I'm + + + align:start position:0% +of the idea that uh I mean what what I'm +tossing around in my head is that uh one + + align:start position:0% +tossing around in my head is that uh one + + + align:start position:0% +tossing around in my head is that uh one +an important part of scientific + + align:start position:0% +an important part of scientific + + + align:start position:0% +an important part of scientific +creativity is uh personal expression and + + align:start position:0% +creativity is uh personal expression and + + + align:start position:0% +creativity is uh personal expression and +that uh what you're expressing is your + + align:start position:0% +that uh what you're expressing is your + + + align:start position:0% +that uh what you're expressing is your +worldview and specific uh your belief + + align:start position:0% +worldview and specific uh your belief + + + align:start position:0% +worldview and specific uh your belief +about the nature of the world or the + + align:start position:0% +about the nature of the world or the + + + align:start position:0% +about the nature of the world or the +metaphysics of the world. And it seems + + align:start position:0% +metaphysics of the world. And it seems + + + align:start position:0% +metaphysics of the world. And it seems +to me that if you take scientific or if + + align:start position:0% +to me that if you take scientific or if + + + align:start position:0% +to me that if you take scientific or if +you take creativity in that way then it + + align:start position:0% +you take creativity in that way then it + + + align:start position:0% +you take creativity in that way then it +has a function that it it has a function + + align:start position:0% +has a function that it it has a function + + + align:start position:0% +has a function that it it has a function +that matches our intentions or our + + align:start position:0% +that matches our intentions or our + + + align:start position:0% +that matches our intentions or our +motivations in life. And you know + + align:start position:0% +motivations in life. And you know + + + align:start position:0% +motivations in life. And you know +Arnheim would say that function is to + + align:start position:0% +Arnheim would say that function is to + + + align:start position:0% +Arnheim would say that function is to +keep us balanced in the face of the + + align:start position:0% +keep us balanced in the face of the + + + align:start position:0% +keep us balanced in the face of the +destructive or or disordering influences + + align:start position:0% +destructive or or disordering influences + + + align:start position:0% +destructive or or disordering influences +of the world. And you know this is + + align:start position:0% +of the world. And you know this is + + + align:start position:0% +of the world. And you know this is +something that I just wanted to throw + + align:start position:0% +something that I just wanted to throw + + + align:start position:0% +something that I just wanted to throw +out see what people thought of it. It + + align:start position:0% +out see what people thought of it. It + + + align:start position:0% +out see what people thought of it. It +sort of makes I can sort of agree with + + align:start position:0% +sort of makes I can sort of agree with + + + align:start position:0% +sort of makes I can sort of agree with +that on a um everyday kind of scale just + + align:start position:0% +that on a um everyday kind of scale just + + + align:start position:0% +that on a um everyday kind of scale just +like simple problems like being on the + + align:start position:0% +like simple problems like being on the + + + align:start position:0% +like simple problems like being on the +highway and you ran out of and you run + + align:start position:0% +highway and you ran out of and you run + + + align:start position:0% +highway and you ran out of and you run +out of gas in your car. Well, you had to + + align:start position:0% +out of gas in your car. Well, you had to + + + align:start position:0% +out of gas in your car. Well, you had to +have a creative solution to solve that + + align:start position:0% +have a creative solution to solve that + + + align:start position:0% +have a creative solution to solve that +random event in order to make sense out + + align:start position:0% +random event in order to make sense out + + + align:start position:0% +random event in order to make sense out +of it. So, on a small scale, I can see + + align:start position:0% +of it. So, on a small scale, I can see + + + align:start position:0% +of it. So, on a small scale, I can see +that. But in terms of art and beauty, I + + align:start position:0% +that. But in terms of art and beauty, I + + + align:start position:0% +that. But in terms of art and beauty, I +don't know. + + align:start position:0% +don't know. + + + align:start position:0% +don't know. +So + + align:start position:0% +So + + + align:start position:0% +So +yeah, I mean it seems to me like from + + align:start position:0% +yeah, I mean it seems to me like from + + + align:start position:0% +yeah, I mean it seems to me like from +the way you describe it, it sounds like + + align:start position:0% +the way you describe it, it sounds like + + + align:start position:0% +the way you describe it, it sounds like +the level at which he's he's making this + + align:start position:0% +the level at which he's he's making this + + + align:start position:0% +the level at which he's he's making this +argument in sort of a, you know, big + + align:start position:0% +argument in sort of a, you know, big + + + align:start position:0% +argument in sort of a, you know, big +broad abstract sense of, you know, art + + align:start position:0% +broad abstract sense of, you know, art + + + align:start position:0% +broad abstract sense of, you know, art +helps us feel better about the world + + align:start position:0% +helps us feel better about the world + + + align:start position:0% +helps us feel better about the world +around us and whatnot. uh I don't think + + align:start position:0% +around us and whatnot. uh I don't think + + + align:start position:0% +around us and whatnot. uh I don't think +that that makes a whole lot of sense in + + align:start position:0% +that that makes a whole lot of sense in + + + align:start position:0% +that that makes a whole lot of sense in +terms of an evolutionary perspective if + + align:start position:0% +terms of an evolutionary perspective if + + + align:start position:0% +terms of an evolutionary perspective if +if you take that sort of view of of + + align:start position:0% +if you take that sort of view of of + + + align:start position:0% +if you take that sort of view of of +cognitive development and that things + + align:start position:0% +cognitive development and that things + + + align:start position:0% +cognitive development and that things +evolve or aspects of of cognition uh + + align:start position:0% +evolve or aspects of of cognition uh + + + align:start position:0% +evolve or aspects of of cognition uh +evolve to fit some uh evolutionary need. + + align:start position:0% +evolve to fit some uh evolutionary need. + + + align:start position:0% +evolve to fit some uh evolutionary need. +It makes a lot more sense that + + align:start position:0% +It makes a lot more sense that + + + align:start position:0% +It makes a lot more sense that +creativity would have to do with + + align:start position:0% +creativity would have to do with + + + align:start position:0% +creativity would have to do with +something a lot simpler where it's like + + align:start position:0% +something a lot simpler where it's like + + + align:start position:0% +something a lot simpler where it's like +you know pattern recognition or or you + + align:start position:0% +you know pattern recognition or or you + + + align:start position:0% +you know pattern recognition or or you +know such more more fundamental things + + align:start position:0% +know such more more fundamental things + + + align:start position:0% +know such more more fundamental things +like that um that would help our species + + align:start position:0% +like that um that would help our species + + + align:start position:0% +like that um that would help our species +survive um you know seeing new links + + align:start position:0% +survive um you know seeing new links + + + align:start position:0% +survive um you know seeing new links +between different things. Well, look, + + align:start position:0% +between different things. Well, look, + + + align:start position:0% +between different things. Well, look, +think of it this way. Uh, you're having + + align:start position:0% +think of it this way. Uh, you're having + + + align:start position:0% +think of it this way. Uh, you're having +a fight with your girlfriend and so you + + align:start position:0% +a fight with your girlfriend and so you + + + align:start position:0% +a fight with your girlfriend and so you +go to the movies and it really is a work + + align:start position:0% +go to the movies and it really is a work + + + align:start position:0% +go to the movies and it really is a work +of art that you whose beauty you can + + align:start position:0% +of art that you whose beauty you can + + + align:start position:0% +of art that you whose beauty you can +perceive and uh whose story is + + align:start position:0% +perceive and uh whose story is + + + align:start position:0% +perceive and uh whose story is +meaningful and you come out having had + + align:start position:0% +meaningful and you come out having had + + + align:start position:0% +meaningful and you come out having had +what John Dewey calls an experience. You + + align:start position:0% +what John Dewey calls an experience. You + + + align:start position:0% +what John Dewey calls an experience. You +remember I was discuss that + + align:start position:0% +remember I was discuss that + + + align:start position:0% +remember I was discuss that +the aesthetic is having an experience. + + align:start position:0% +the aesthetic is having an experience. + + + align:start position:0% +the aesthetic is having an experience. +You come out really is an experience. + + align:start position:0% +You come out really is an experience. + + + align:start position:0% +You come out really is an experience. +that might then cure your depression. + + align:start position:0% +that might then cure your depression. + + + align:start position:0% +that might then cure your depression. +That might enable you to go out and face + + align:start position:0% +That might enable you to go out and face + + + align:start position:0% +That might enable you to go out and face +the problems of the world and call up + + align:start position:0% +the problems of the world and call up + + + align:start position:0% +the problems of the world and call up +your girlfriend and settle your + + align:start position:0% +your girlfriend and settle your + + + align:start position:0% +your girlfriend and settle your +problems. I mean, I'm I'm not saying I'm + + align:start position:0% +problems. I mean, I'm I'm not saying I'm + + + align:start position:0% +problems. I mean, I'm I'm not saying I'm +not saying though that uh creative + + align:start position:0% +not saying though that uh creative + + + align:start position:0% +not saying though that uh creative +things can't do that. I'm saying that + + align:start position:0% +things can't do that. I'm saying that + + + align:start position:0% +things can't do that. I'm saying that +their primary function is something else + + align:start position:0% +their primary function is something else + + + align:start position:0% +their primary function is something else +and anything along those lines that is + + align:start position:0% +and anything along those lines that is + + + align:start position:0% +and anything along those lines that is +derived from it is secondary to its its + + align:start position:0% +derived from it is secondary to its its + + + align:start position:0% +derived from it is secondary to its its +fundamental purpose which exists. Is it + + align:start position:0% +fundamental purpose which exists. Is it + + + align:start position:0% +fundamental purpose which exists. Is it +there the the these other things the + + align:start position:0% +there the the these other things the + + + align:start position:0% +there the the these other things the +primary purpose or these the mechanisms + + align:start position:0% +primary purpose or these the mechanisms + + + align:start position:0% +primary purpose or these the mechanisms +by which it works? So it sounds like + + align:start position:0% +by which it works? So it sounds like + + + align:start position:0% +by which it works? So it sounds like +you're saying something interesting + + align:start position:0% +you're saying something interesting + + + align:start position:0% +you're saying something interesting +which is that you're making a + + align:start position:0% +which is that you're making a + + + align:start position:0% +which is that you're making a +distinction between uh function and + + align:start position:0% +distinction between uh function and + + + align:start position:0% +distinction between uh function and +evolutionary terms and I had sort of + + align:start position:0% +evolutionary terms and I had sort of + + + align:start position:0% +evolutionary terms and I had sort of +been thinking in terms of uh intention + + align:start position:0% +been thinking in terms of uh intention + + + align:start position:0% +been thinking in terms of uh intention +or motivation which when + + align:start position:0% +or motivation which when + + + align:start position:0% +or motivation which when +science does all and well until you + + align:start position:0% +science does all and well until you + + + align:start position:0% +science does all and well until you +start to have to deal with the question + + align:start position:0% +start to have to deal with the question + + + align:start position:0% +start to have to deal with the question +of why we do the things that we do and + + align:start position:0% +of why we do the things that we do and + + + align:start position:0% +of why we do the things that we do and +whether we are allowed to have such + + align:start position:0% +whether we are allowed to have such + + + align:start position:0% +whether we are allowed to have such +things as motivation and intention uh + + align:start position:0% +things as motivation and intention uh + + + align:start position:0% +things as motivation and intention uh +especially in the scientific + + align:start position:0% +especially in the scientific + + + align:start position:0% +especially in the scientific +description. So wait, hang on. Why would + + align:start position:0% +description. So wait, hang on. Why would + + + align:start position:0% +description. So wait, hang on. Why would +you not be allowed to have motivation + + align:start position:0% +you not be allowed to have motivation + + + align:start position:0% +you not be allowed to have motivation +and intention? Surely that's kind of the + + align:start position:0% +and intention? Surely that's kind of the + + + align:start position:0% +and intention? Surely that's kind of the +basis of why you're doing science. + + align:start position:0% +basis of why you're doing science. + + + align:start position:0% +basis of why you're doing science. +Well, so but the question is can you + + align:start position:0% +Well, so but the question is can you + + + align:start position:0% +Well, so but the question is can you +does that fit within a scientific + + align:start position:0% +does that fit within a scientific + + + align:start position:0% +does that fit within a scientific +theory? I mean the + + align:start position:0% +theory? I mean the + + + align:start position:0% +theory? I mean the +see if I can explain this. Uh it + + align:start position:0% +see if I can explain this. Uh it + + + align:start position:0% +see if I can explain this. Uh it +revolves around the question of free + + align:start position:0% +revolves around the question of free + + + align:start position:0% +revolves around the question of free +will. + + align:start position:0% +will. + + + align:start position:0% +will. +um + + align:start position:0% +um + + + align:start position:0% +um +primarily in terms of uh taking human + + align:start position:0% +primarily in terms of uh taking human + + + align:start position:0% +primarily in terms of uh taking human +behavior down to the lowest level, the + + align:start position:0% +behavior down to the lowest level, the + + + align:start position:0% +behavior down to the lowest level, the +most fundamental theory of science which + + align:start position:0% +most fundamental theory of science which + + + align:start position:0% +most fundamental theory of science which +has its own problems. But it trying to + + align:start position:0% +has its own problems. But it trying to + + + align:start position:0% +has its own problems. But it trying to +reduce things that we claim we do + + align:start position:0% +reduce things that we claim we do + + + align:start position:0% +reduce things that we claim we do +because of emotions or desires down to + + align:start position:0% +because of emotions or desires down to + + + align:start position:0% +because of emotions or desires down to +atoms or quantum mechanics at that + + align:start position:0% +atoms or quantum mechanics at that + + + align:start position:0% +atoms or quantum mechanics at that +level. You know, previously it was to + + align:start position:0% +level. You know, previously it was to + + + align:start position:0% +level. You know, previously it was to +classical mechanics where Newton said + + align:start position:0% +classical mechanics where Newton said + + + align:start position:0% +classical mechanics where Newton said +the world is I don't know if the claim + + align:start position:0% +the world is I don't know if the claim + + + align:start position:0% +the world is I don't know if the claim +was that the world is clockwork and it's + + align:start position:0% +was that the world is clockwork and it's + + + align:start position:0% +was that the world is clockwork and it's +deterministic. And that was a real + + align:start position:0% +deterministic. And that was a real + + + align:start position:0% +deterministic. And that was a real +problem for intentionality and free will + + align:start position:0% +problem for intentionality and free will + + + align:start position:0% +problem for intentionality and free will +because then if you just knew enough all + + align:start position:0% +because then if you just knew enough all + + + align:start position:0% +because then if you just knew enough all +of human action would be derable by + + align:start position:0% +of human action would be derable by + + + align:start position:0% +of human action would be derable by +logic. When you get to quantum + + align:start position:0% +logic. When you get to quantum + + + align:start position:0% +logic. When you get to quantum +mechanics, if you take quantum mechanics + + align:start position:0% +mechanics, if you take quantum mechanics + + + align:start position:0% +mechanics, if you take quantum mechanics +as true, then suddenly it's + + align:start position:0% +as true, then suddenly it's + + + align:start position:0% +as true, then suddenly it's +probabilistic, but it's still governed + + align:start position:0% +probabilistic, but it's still governed + + + align:start position:0% +probabilistic, but it's still governed +by laws. And so you still don't get the + + align:start position:0% +by laws. And so you still don't get the + + + align:start position:0% +by laws. And so you still don't get the +same kind of uh I actually am a person + + align:start position:0% +same kind of uh I actually am a person + + + align:start position:0% +same kind of uh I actually am a person +and I have emotions that I can take as + + align:start position:0% +and I have emotions that I can take as + + + align:start position:0% +and I have emotions that I can take as +holes. I have + + align:start position:0% +holes. I have + + + align:start position:0% +holes. I have +because the claim of science is that no + + align:start position:0% +because the claim of science is that no + + + align:start position:0% +because the claim of science is that no +what you want to phrase as emotions need + + align:start position:0% +what you want to phrase as emotions need + + + align:start position:0% +what you want to phrase as emotions need +to be or are better expressed as laws of + + align:start position:0% +to be or are better expressed as laws of + + + align:start position:0% +to be or are better expressed as laws of +quantum mechanics. So they want to + + align:start position:0% +quantum mechanics. So they want to + + + align:start position:0% +quantum mechanics. So they want to +replace emotions with quantum mechanics + + align:start position:0% +replace emotions with quantum mechanics + + + align:start position:0% +replace emotions with quantum mechanics +and at that level the human + + align:start position:0% +and at that level the human + + + align:start position:0% +and at that level the human +intentionality goes away. I don't think + + align:start position:0% +intentionality goes away. I don't think + + + align:start position:0% +intentionality goes away. I don't think +I don't think they're trying to replace + + align:start position:0% +I don't think they're trying to replace + + + align:start position:0% +I don't think they're trying to replace +Yeah. I mean there are many people who + + align:start position:0% +Yeah. I mean there are many people who + + + align:start position:0% +Yeah. I mean there are many people who +don't there are many people who don't + + align:start position:0% +don't there are many people who don't + + + align:start position:0% +don't there are many people who don't +agree with that. So it's not universal + + align:start position:0% +agree with that. So it's not universal + + + align:start position:0% +agree with that. So it's not universal +but it is a real it is a real it's + + align:start position:0% +but it is a real it is a real it's + + + align:start position:0% +but it is a real it is a real it's +reductionism scientific reductionism and + + align:start position:0% +reductionism scientific reductionism and + + + align:start position:0% +reductionism scientific reductionism and +philosophy. So it I'm not making it up + + align:start position:0% +philosophy. So it I'm not making it up + + + align:start position:0% +philosophy. So it I'm not making it up +but I agree that not everybody goes + + align:start position:0% +but I agree that not everybody goes + + + align:start position:0% +but I agree that not everybody goes +along with that. Just know how to think. + + align:start position:0% +along with that. Just know how to think. + + + align:start position:0% +along with that. Just know how to think. +So anyway the the distinction that I was + + align:start position:0% +So anyway the the distinction that I was + + + align:start position:0% +So anyway the the distinction that I was +you know when I was throwing function + + align:start position:0% +you know when I was throwing function + + + align:start position:0% +you know when I was throwing function +and I actually meant in a in a + + align:start position:0% +and I actually meant in a in a + + + align:start position:0% +and I actually meant in a in a +intentional sort of way. So it's + + align:start position:0% +intentional sort of way. So it's + + + align:start position:0% +intentional sort of way. So it's +interesting to then think of it in terms + + align:start position:0% +interesting to then think of it in terms + + + align:start position:0% +interesting to then think of it in terms +of an evolutionary sense. + + align:start position:0% + + + + align:start position:0% + +I don't know whether there's room for + + align:start position:0% +I don't know whether there's room for + + + align:start position:0% +I don't know whether there's room for +both of them at the same time or what + + align:start position:0% +both of them at the same time or what + + + align:start position:0% +both of them at the same time or what +you think about them. + + align:start position:0% + + + + align:start position:0% + +Do you want a paper? Well, did you have + + align:start position:0% +Do you want a paper? Well, did you have + + + align:start position:0% +Do you want a paper? Well, did you have +I was thinking they both sort of they + + align:start position:0% +I was thinking they both sort of they + + + align:start position:0% +I was thinking they both sort of they +can fit together. I mean they're just + + align:start position:0% +can fit together. I mean they're just + + + align:start position:0% +can fit together. I mean they're just +different meanings of the same sort of + + align:start position:0% +different meanings of the same sort of + + + align:start position:0% +different meanings of the same sort of +terminology and that I mean it's I think + + align:start position:0% +terminology and that I mean it's I think + + + align:start position:0% +terminology and that I mean it's I think +uh a lot I mean a lot of times actually + + align:start position:0% +uh a lot I mean a lot of times actually + + + align:start position:0% +uh a lot I mean a lot of times actually +in evolution they things evolve for one + + align:start position:0% +in evolution they things evolve for one + + + align:start position:0% +in evolution they things evolve for one +purpose and than used for another. I + + align:start position:0% +purpose and than used for another. I + + + align:start position:0% +purpose and than used for another. I +mean uh kind of what we were talking + + align:start position:0% +mean uh kind of what we were talking + + + align:start position:0% +mean uh kind of what we were talking +about earlier where human intelligence + + align:start position:0% +about earlier where human intelligence + + + align:start position:0% +about earlier where human intelligence +general evolved to help us survive. It + + align:start position:0% +general evolved to help us survive. It + + + align:start position:0% +general evolved to help us survive. It +didn't evolve for us to say you know sit + + align:start position:0% +didn't evolve for us to say you know sit + + + align:start position:0% +didn't evolve for us to say you know sit +around in a classroom and discuss + + align:start position:0% +around in a classroom and discuss + + + align:start position:0% +around in a classroom and discuss +philosophy. Nevertheless, we use it for + + align:start position:0% +philosophy. Nevertheless, we use it for + + + align:start position:0% +philosophy. Nevertheless, we use it for +that. Um and so there are those two sort + + align:start position:0% +that. Um and so there are those two sort + + + align:start position:0% +that. Um and so there are those two sort +of different types of function. + + align:start position:0% + + + + align:start position:0% + +So then my sense what would be the + + align:start position:0% +So then my sense what would be the + + + align:start position:0% +So then my sense what would be the +purpose of intellect + + align:start position:0% +purpose of intellect + + + align:start position:0% +purpose of intellect +to help us survive. It's our you know at + + align:start position:0% +to help us survive. It's our you know at + + + align:start position:0% +to help us survive. It's our you know at +the same time the animals are surviving + + align:start position:0% +the same time the animals are surviving + + + align:start position:0% +the same time the animals are surviving +just as well. + + align:start position:0% +just as well. + + + align:start position:0% +just as well. +They have different adaptations, + + align:start position:0% +They have different adaptations, + + + align:start position:0% +They have different adaptations, +multiple solutions to the same problem + + align:start position:0% +multiple solutions to the same problem + + + align:start position:0% +multiple solutions to the same problem +of survival, + + align:start position:0% + + + + align:start position:0% + +but the simplest solution tends to be + + align:start position:0% +but the simplest solution tends to be + + + align:start position:0% +but the simplest solution tends to be +the more right one. + + align:start position:0% +the more right one. + + + align:start position:0% +the more right one. +That assumes somebody sitting there + + align:start position:0% +That assumes somebody sitting there + + + align:start position:0% +That assumes somebody sitting there +designing it, but let's not get into + + align:start position:0% +designing it, but let's not get into + + + align:start position:0% +designing it, but let's not get into +that. Okay. + + align:start position:0% + + + + align:start position:0% + +um the way human nature seems to be + + align:start position:0% +um the way human nature seems to be + + + align:start position:0% +um the way human nature seems to be +evolving + + align:start position:0% +evolving + + + align:start position:0% +evolving +more and there'll be more and more + + align:start position:0% +more and there'll be more and more + + + align:start position:0% +more and there'll be more and more +people harder and harder to deal with + + align:start position:0% +people harder and harder to deal with + + + align:start position:0% +people harder and harder to deal with +them and therefore probably more chaos + + align:start position:0% +them and therefore probably more chaos + + + align:start position:0% +them and therefore probably more chaos +in political and social structures. Um + + align:start position:0% +in political and social structures. Um + + + align:start position:0% +in political and social structures. Um +and one one way of dealing with that is + + align:start position:0% +and one one way of dealing with that is + + + align:start position:0% +and one one way of dealing with that is +by destroying them in bigger and bigger + + align:start position:0% +by destroying them in bigger and bigger + + + align:start position:0% +by destroying them in bigger and bigger +nuclear explosions. of the world that in + + align:start position:0% +nuclear explosions. of the world that in + + + align:start position:0% +nuclear explosions. of the world that in +other words that the nature given the + + align:start position:0% +other words that the nature given the + + + align:start position:0% +other words that the nature given the +intellect we have given the slowness at + + align:start position:0% +intellect we have given the slowness at + + + align:start position:0% +intellect we have given the slowness at +which evolution works. There may be no + + align:start position:0% +which evolution works. There may be no + + + align:start position:0% +which evolution works. There may be no +way in which we can ever cope with + + align:start position:0% +way in which we can ever cope with + + + align:start position:0% +way in which we can ever cope with +fundamental problems of a small planet + + align:start position:0% +fundamental problems of a small planet + + + align:start position:0% +fundamental problems of a small planet +overpop populated and with uh creatures + + align:start position:0% +overpop populated and with uh creatures + + + align:start position:0% +overpop populated and with uh creatures +dominating it who have so many + + align:start position:0% +dominating it who have so many + + + align:start position:0% +dominating it who have so many +antisocial attitudes and feelings. + + align:start position:0% +antisocial attitudes and feelings. + + + align:start position:0% +antisocial attitudes and feelings. +If you take that point of view and then + + align:start position:0% +If you take that point of view and then + + + align:start position:0% +If you take that point of view and then +compare the state of animals in the + + align:start position:0% +compare the state of animals in the + + + align:start position:0% +compare the state of animals in the +rainforest who are not troubled by human + + align:start position:0% +rainforest who are not troubled by human + + + align:start position:0% +rainforest who are not troubled by human +beings uh al and particular species like + + align:start position:0% +beings uh al and particular species like + + + align:start position:0% +beings uh al and particular species like +the bonos + + align:start position:0% +the bonos + + + align:start position:0% +the bonos +um who are so similar to us or sort of + + align:start position:0% +um who are so similar to us or sort of + + + align:start position:0% +um who are so similar to us or sort of +variation of chimpanzees. + + align:start position:0% +variation of chimpanzees. + + + align:start position:0% +variation of chimpanzees. +Um you might say you know why uh why be + + align:start position:0% +Um you might say you know why uh why be + + + align:start position:0% +Um you might say you know why uh why be +human? Why who needs all of this? the + + align:start position:0% +human? Why who needs all of this? the + + + align:start position:0% +human? Why who needs all of this? the +bonos. Um I mean chimpanzees have many + + align:start position:0% +bonos. Um I mean chimpanzees have many + + + align:start position:0% +bonos. Um I mean chimpanzees have many +of our aggressive + + align:start position:0% +of our aggressive + + + align:start position:0% +of our aggressive +and violent traits + + align:start position:0% +and violent traits + + + align:start position:0% +and violent traits +because we share so many so many genes. + + align:start position:0% +because we share so many so many genes. + + + align:start position:0% +because we share so many so many genes. +But the bonos for some reason have a + + align:start position:0% +But the bonos for some reason have a + + + align:start position:0% +But the bonos for some reason have a +slightly different program + + align:start position:0% +slightly different program + + + align:start position:0% +slightly different program +and they don't fight. They just make + + align:start position:0% +and they don't fight. They just make + + + align:start position:0% +and they don't fight. They just make +love all the time and they seem to have + + align:start position:0% +love all the time and they seem to have + + + align:start position:0% +love all the time and they seem to have +a very pleasant existence except when + + align:start position:0% +a very pleasant existence except when + + + align:start position:0% +a very pleasant existence except when +the others kill them for reasons of + + align:start position:0% +the others kill them for reasons of + + + align:start position:0% +the others kill them for reasons of +their own. But if thinking of the state + + align:start position:0% +their own. But if thinking of the state + + + align:start position:0% +their own. But if thinking of the state +of the species independent of their + + align:start position:0% +of the species independent of their + + + align:start position:0% +of the species independent of their +interaction with one another, one might + + align:start position:0% +interaction with one another, one might + + + align:start position:0% +interaction with one another, one might +say how much better it would be to be a + + align:start position:0% +say how much better it would be to be a + + + align:start position:0% +say how much better it would be to be a +bono than a human being. + + align:start position:0% + + + + align:start position:0% + +And if that's true, then we could start + + align:start position:0% +And if that's true, then we could start + + + align:start position:0% +And if that's true, then we could start +finding other species that one would be + + align:start position:0% +finding other species that one would be + + + align:start position:0% +finding other species that one would be +better off being. + + align:start position:0% +better off being. + + + align:start position:0% +better off being. +I mean, + + align:start position:0% +I mean, + + + align:start position:0% +I mean, +that seems to me similar to the claim of + + align:start position:0% +that seems to me similar to the claim of + + + align:start position:0% +that seems to me similar to the claim of +the noble savage + + align:start position:0% +the noble savage + + + align:start position:0% +the noble savage +who was the primitive state of man that + + align:start position:0% +who was the primitive state of man that + + + align:start position:0% +who was the primitive state of man that +lived in harmony with nature and uh had + + align:start position:0% +lived in harmony with nature and uh had + + + align:start position:0% +lived in harmony with nature and uh had +a small tight-knit social group and you + + align:start position:0% +a small tight-knit social group and you + + + align:start position:0% +a small tight-knit social group and you +know lived off the land and sort of the + + align:start position:0% +know lived off the land and sort of the + + + align:start position:0% +know lived off the land and sort of the +pure natural state that + + align:start position:0% +pure natural state that + + + align:start position:0% +pure natural state that +was best for humankind. Well, there's a + + align:start position:0% +was best for humankind. Well, there's a + + + align:start position:0% +was best for humankind. Well, there's a +confusion in that because we live close + + align:start position:0% +confusion in that because we live close + + + align:start position:0% +confusion in that because we live close +to nature + + align:start position:0% +to nature + + + align:start position:0% +to nature +where all what we do is natural and it's + + align:start position:0% +where all what we do is natural and it's + + + align:start position:0% +where all what we do is natural and it's +all a function of natural impulses in + + align:start position:0% +all a function of natural impulses in + + + align:start position:0% +all a function of natural impulses in +us. It's just that the consequences + + align:start position:0% +us. It's just that the consequences + + + align:start position:0% +us. It's just that the consequences +um don't conduce to the system of values + + align:start position:0% +um don't conduce to the system of values + + + align:start position:0% +um don't conduce to the system of values +that we've also acquired and they don't + + align:start position:0% +that we've also acquired and they don't + + + align:start position:0% +that we've also acquired and they don't +bring about a kind of + + align:start position:0% +bring about a kind of + + + align:start position:0% +bring about a kind of +brute happiness that everybody would + + align:start position:0% +brute happiness that everybody would + + + align:start position:0% +brute happiness that everybody would +like to have. So it isn't as if the + + align:start position:0% +like to have. So it isn't as if the + + + align:start position:0% +like to have. So it isn't as if the +Bonos are closer to nature. It's just + + align:start position:0% +Bonos are closer to nature. It's just + + + align:start position:0% +Bonos are closer to nature. It's just +that they have a a better relationship + + align:start position:0% +that they have a a better relationship + + + align:start position:0% +that they have a a better relationship +to nature than we do. Both of us being + + align:start position:0% +to nature than we do. Both of us being + + + align:start position:0% +to nature than we do. Both of us being +uh in doing what comes naturally. But + + align:start position:0% +uh in doing what comes naturally. But + + + align:start position:0% +uh in doing what comes naturally. But +I'm not convinced that the noble savage + + align:start position:0% +I'm not convinced that the noble savage + + + align:start position:0% +I'm not convinced that the noble savage +ever existed. I think it's that's + + align:start position:0% +ever existed. I think it's that's + + + align:start position:0% +ever existed. I think it's that's +because of the contradiction in the + + align:start position:0% +because of the contradiction in the + + + align:start position:0% +because of the contradiction in the +terms. If he's noble, he's not going to + + align:start position:0% +terms. If he's noble, he's not going to + + + align:start position:0% +terms. If he's noble, he's not going to +be a savage. And if he's a savage + + align:start position:0% +be a savage. And if he's a savage + + + align:start position:0% +be a savage. And if he's a savage +savage, he's not going to be noble. But + + align:start position:0% +savage, he's not going to be noble. But + + + align:start position:0% +savage, he's not going to be noble. But +um eliminating all of that romantic + + align:start position:0% +um eliminating all of that romantic + + + align:start position:0% +um eliminating all of that romantic +verbiage of one might say uh there are + + align:start position:0% +verbiage of one might say uh there are + + + align:start position:0% +verbiage of one might say uh there are +species we name them um who uh are + + align:start position:0% +species we name them um who uh are + + + align:start position:0% +species we name them um who uh are +better off in the world would be better + + align:start position:0% +better off in the world would be better + + + align:start position:0% +better off in the world would be better +off if they were the dominant creatures + + align:start position:0% +off if they were the dominant creatures + + + align:start position:0% +off if they were the dominant creatures +rather than us. You see so I'm you get + + align:start position:0% +rather than us. You see so I'm you get + + + align:start position:0% +rather than us. You see so I'm you get +my idea I I don't want to pursue the + + align:start position:0% +my idea I I don't want to pursue the + + + align:start position:0% +my idea I I don't want to pursue the +question about the noble savage or I + + align:start position:0% +question about the noble savage or I + + + align:start position:0% +question about the noble savage or I +encourage you maybe to think beyond + + align:start position:0% +encourage you maybe to think beyond + + + align:start position:0% +encourage you maybe to think beyond +that. + + align:start position:0% +that. + + + align:start position:0% +that. +Well it's just a question of + + align:start position:0% +Well it's just a question of + + + align:start position:0% +Well it's just a question of +It it's somewhat ironic to say uh the + + align:start position:0% +It it's somewhat ironic to say uh the + + + align:start position:0% +It it's somewhat ironic to say uh the +world would be better off put these + + align:start position:0% +world would be better off put these + + + align:start position:0% +world would be better off put these +species in charge given that it's us + + align:start position:0% +species in charge given that it's us + + + align:start position:0% +species in charge given that it's us +making the value decision + + align:start position:0% +making the value decision + + + align:start position:0% +making the value decision +that and no no no not no that's + + align:start position:0% +that and no no no not no that's + + + align:start position:0% +that and no no no not no that's +contradictory. If we make the value + + align:start position:0% +contradictory. If we make the value + + + align:start position:0% +contradictory. If we make the value +decisions we're already separating + + align:start position:0% +decisions we're already separating + + + align:start position:0% +decisions we're already separating +ourselves from them and assuming that we + + align:start position:0% +ourselves from them and assuming that we + + + align:start position:0% +ourselves from them and assuming that we +have a superiority. I'm saying uh if you + + align:start position:0% +have a superiority. I'm saying uh if you + + + align:start position:0% +have a superiority. I'm saying uh if you +accept our value + + align:start position:0% +accept our value + + + align:start position:0% +accept our value +system of values and there is a certain + + align:start position:0% +system of values and there is a certain + + + align:start position:0% +system of values and there is a certain +degree of agreement uh about the + + align:start position:0% +degree of agreement uh about the + + + align:start position:0% +degree of agreement uh about the +goodness of happiness, the goodness of + + align:start position:0% +goodness of happiness, the goodness of + + + align:start position:0% +goodness of happiness, the goodness of +being peaceful and getting along with + + align:start position:0% +being peaceful and getting along with + + + align:start position:0% +being peaceful and getting along with +your roommates uh and so on. uh + + align:start position:0% +your roommates uh and so on. uh + + + align:start position:0% +your roommates uh and so on. uh +you can then say given those values + + align:start position:0% +you can then say given those values + + + align:start position:0% +you can then say given those values +um there are other other species who + + align:start position:0% +um there are other other species who + + + align:start position:0% +um there are other other species who +would do a better job of living up to + + align:start position:0% +would do a better job of living up to + + + align:start position:0% +would do a better job of living up to +them if only we didn't have our + + align:start position:0% +them if only we didn't have our + + + align:start position:0% +them if only we didn't have our +dominance over those. But but I mean it + + align:start position:0% +dominance over those. But but I mean it + + + align:start position:0% +dominance over those. But but I mean it +could be that the the whole reason that + + align:start position:0% +could be that the the whole reason that + + + align:start position:0% +could be that the the whole reason that +these species aren't dominant is because + + align:start position:0% +these species aren't dominant is because + + + align:start position:0% +these species aren't dominant is because +of those very traits that make them sort + + align:start position:0% +of those very traits that make them sort + + + align:start position:0% +of those very traits that make them sort +of you know work well with their + + align:start position:0% +of you know work well with their + + + align:start position:0% +of you know work well with their +environment. they they tend to be a + + align:start position:0% +environment. they they tend to be a + + + align:start position:0% +environment. they they tend to be a +little bit more passive and it's it's + + align:start position:0% +little bit more passive and it's it's + + + align:start position:0% +little bit more passive and it's it's +our sort of destructive dominant nature + + align:start position:0% +our sort of destructive dominant nature + + + align:start position:0% +our sort of destructive dominant nature +uh that is the reason we're dominant. + + align:start position:0% +uh that is the reason we're dominant. + + + align:start position:0% +uh that is the reason we're dominant. +And so you can argue theoretically, + + align:start position:0% +And so you can argue theoretically, + + + align:start position:0% +And so you can argue theoretically, +yeah, it might be better if some other + + align:start position:0% +yeah, it might be better if some other + + + align:start position:0% +yeah, it might be better if some other +species were in charge, but it's it's + + align:start position:0% +species were in charge, but it's it's + + + align:start position:0% +species were in charge, but it's it's +not something that could ever actually + + align:start position:0% +not something that could ever actually + + + align:start position:0% +not something that could ever actually +occur because of the actual uh because + + align:start position:0% +occur because of the actual uh because + + + align:start position:0% +occur because of the actual uh because +of the because the happiness comes from + + align:start position:0% +of the because the happiness comes from + + + align:start position:0% +of the because the happiness comes from +not being in charge. Yeah, something + + align:start position:0% +not being in charge. Yeah, something + + + align:start position:0% +not being in charge. Yeah, something +like that, right? Or I mean there's I I + + align:start position:0% +like that, right? Or I mean there's I I + + + align:start position:0% +like that, right? Or I mean there's I I +I also think there's a problem with + + align:start position:0% +I also think there's a problem with + + + align:start position:0% +I also think there's a problem with +trying to say what would be better with + + align:start position:0% +trying to say what would be better with + + + align:start position:0% +trying to say what would be better with +than us given that we're judging as us. + + align:start position:0% +than us given that we're judging as us. + + + align:start position:0% +than us given that we're judging as us. +You know if if if humans are so flawed + + align:start position:0% +You know if if if humans are so flawed + + + align:start position:0% +You know if if if humans are so flawed +that they would be better replaced by + + align:start position:0% +that they would be better replaced by + + + align:start position:0% +that they would be better replaced by +something else then it seems strange to + + align:start position:0% +something else then it seems strange to + + + align:start position:0% +something else then it seems strange to +judge what should be replaced you know + + align:start position:0% +judge what should be replaced you know + + + align:start position:0% +judge what should be replaced you know +what what should replace humans as + + align:start position:0% +what what should replace humans as + + + align:start position:0% +what what should replace humans as +humans. That might be the flaw in the + + align:start position:0% +humans. That might be the flaw in the + + + align:start position:0% +humans. That might be the flaw in the +first place. It could be an inescapable + + align:start position:0% +first place. It could be an inescapable + + + align:start position:0% +first place. It could be an inescapable +problem. Um, that may be an interesting + + align:start position:0% +problem. Um, that may be an interesting + + + align:start position:0% +problem. Um, that may be an interesting +insight into the flaw in all morality + + align:start position:0% +insight into the flaw in all morality + + + align:start position:0% +insight into the flaw in all morality +because if if you're going to be moral, + + align:start position:0% +because if if you're going to be moral, + + + align:start position:0% +because if if you're going to be moral, +you have to have a system of values and + + align:start position:0% +you have to have a system of values and + + + align:start position:0% +you have to have a system of values and +standards, right? Uh, but having them + + align:start position:0% +standards, right? Uh, but having them + + + align:start position:0% +standards, right? Uh, but having them +might already disqualify you from living + + align:start position:0% +might already disqualify you from living + + + align:start position:0% +might already disqualify you from living +up to them. + + align:start position:0% + + + + align:start position:0% + +I think I think there are lots of flaws + + align:start position:0% +I think I think there are lots of flaws + + + align:start position:0% +I think I think there are lots of flaws +of that sort in human nature. + + align:start position:0% +of that sort in human nature. + + + align:start position:0% +of that sort in human nature. +So, I don't I'm just sort of reluctant + + align:start position:0% +So, I don't I'm just sort of reluctant + + + align:start position:0% +So, I don't I'm just sort of reluctant +to to uh believe that other species are + + align:start position:0% +to to uh believe that other species are + + + align:start position:0% +to to uh believe that other species are +uh in fact better than we are because + + align:start position:0% +uh in fact better than we are because + + + align:start position:0% +uh in fact better than we are because +the assumption requires us to judge + + align:start position:0% +the assumption requires us to judge + + + align:start position:0% +the assumption requires us to judge +ourselves as so terrible that uh we + + align:start position:0% +ourselves as so terrible that uh we + + + align:start position:0% +ourselves as so terrible that uh we +would be replaced by them. But in fact, + + align:start position:0% +would be replaced by them. But in fact, + + + align:start position:0% +would be replaced by them. But in fact, +we're not fit to make that judgment in + + align:start position:0% +we're not fit to make that judgment in + + + align:start position:0% +we're not fit to make that judgment in +the first place if we are so terrible. + + align:start position:0% +the first place if we are so terrible. + + + align:start position:0% +the first place if we are so terrible. +All right. No. Uh I I would be willing + + align:start position:0% +All right. No. Uh I I would be willing + + + align:start position:0% +All right. No. Uh I I would be willing +to yield that generalization I made if + + align:start position:0% +to yield that generalization I made if + + + align:start position:0% +to yield that generalization I made if +it were agreed that um there is + + align:start position:0% +it were agreed that um there is + + + align:start position:0% +it were agreed that um there is +something radically flawed in our very + + align:start position:0% +something radically flawed in our very + + + align:start position:0% +something radically flawed in our very +being. Now that of course is the view of + + align:start position:0% +being. Now that of course is the view of + + + align:start position:0% +being. Now that of course is the view of +great many religions + + align:start position:0% +great many religions + + + align:start position:0% +great many religions +that man human nature is evil and that + + align:start position:0% +that man human nature is evil and that + + + align:start position:0% +that man human nature is evil and that +um uh there's original sin and therefore + + align:start position:0% +um uh there's original sin and therefore + + + align:start position:0% +um uh there's original sin and therefore +the most you can do is to throw yourself + + align:start position:0% +the most you can do is to throw yourself + + + align:start position:0% +the most you can do is to throw yourself +at the mercy of loving God. Right. So + + align:start position:0% +at the mercy of loving God. Right. So + + + align:start position:0% +at the mercy of loving God. Right. So +that there may be a great deal of + + align:start position:0% +that there may be a great deal of + + + align:start position:0% +that there may be a great deal of +consensus about that. The question is + + align:start position:0% +consensus about that. The question is + + + align:start position:0% +consensus about that. The question is +the idea of flaw what what + + align:start position:0% +the idea of flaw what what + + + align:start position:0% +the idea of flaw what what +interpretation you lay upon it. And that + + align:start position:0% +interpretation you lay upon it. And that + + + align:start position:0% +interpretation you lay upon it. And that +doesn't have to be the same as what it + + align:start position:0% +doesn't have to be the same as what it + + + align:start position:0% +doesn't have to be the same as what it +is in most religions. + + align:start position:0% +is in most religions. + + + align:start position:0% +is in most religions. +Um, in the case of the bonos or the + + align:start position:0% +Um, in the case of the bonos or the + + + align:start position:0% +Um, in the case of the bonos or the +other instinct, other in animals who + + align:start position:0% +other instinct, other in animals who + + + align:start position:0% +other instinct, other in animals who +seem to have a happier relationship with + + align:start position:0% +seem to have a happier relationship with + + + align:start position:0% +seem to have a happier relationship with +their own instincts, we may be + + align:start position:0% +their own instincts, we may be + + + align:start position:0% +their own instincts, we may be +romanticizing them. They're all sorts of + + align:start position:0% +romanticizing them. They're all sorts of + + + align:start position:0% +romanticizing them. They're all sorts of +problems they might have that we never + + align:start position:0% +problems they might have that we never + + + align:start position:0% +problems they might have that we never +know anything about. In fact, I think we + + align:start position:0% +know anything about. In fact, I think we + + + align:start position:0% +know anything about. In fact, I think we +know very little about what it is to be + + align:start position:0% +know very little about what it is to be + + + align:start position:0% +know very little about what it is to be +another member of another species. We + + align:start position:0% +another member of another species. We + + + align:start position:0% +another member of another species. We +don't know what their minds are. um you + + align:start position:0% +don't know what their minds are. um you + + + align:start position:0% +don't know what their minds are. um you +know in the um the um u insects in um in + + align:start position:0% +know in the um the um u insects in um in + + + align:start position:0% +know in the um the um u insects in um in +a colony where there's a queen and + + align:start position:0% +a colony where there's a queen and + + + align:start position:0% +a colony where there's a queen and +there's that class stratification and + + align:start position:0% +there's that class stratification and + + + align:start position:0% +there's that class stratification and +the workers do all the work. Um we don't + + align:start position:0% +the workers do all the work. Um we don't + + + align:start position:0% +the workers do all the work. Um we don't +know how they feel about that. Uh, do + + align:start position:0% +know how they feel about that. Uh, do + + + align:start position:0% +know how they feel about that. Uh, do +they when they pass each other, do they + + align:start position:0% +they when they pass each other, do they + + + align:start position:0% +they when they pass each other, do they +nudge them on the elbow and enjoy their + + align:start position:0% +nudge them on the elbow and enjoy their + + + align:start position:0% +nudge them on the elbow and enjoy their +company and and have a or compete to see + + align:start position:0% +company and and have a or compete to see + + + align:start position:0% +company and and have a or compete to see +who can bring the most food to the to + + align:start position:0% +who can bring the most food to the to + + + align:start position:0% +who can bring the most food to the to +the queen? We have no idea whatsoever + + align:start position:0% +the queen? We have no idea whatsoever + + + align:start position:0% +the queen? We have no idea whatsoever +what's going on in these other other + + align:start position:0% +what's going on in these other other + + + align:start position:0% +what's going on in these other other +species, particularly the insect + + align:start position:0% +species, particularly the insect + + + align:start position:0% +species, particularly the insect +species, but it also would be true of + + align:start position:0% +species, but it also would be true of + + + align:start position:0% +species, but it also would be true of +underground molds and and other animals + + align:start position:0% +underground molds and and other animals + + + align:start position:0% +underground molds and and other animals +that we never try to make sense of. + + align:start position:0% + + + + align:start position:0% + +What about your paper? + + align:start position:0% + + + + align:start position:0% + +Um, + + align:start position:0% +Um, + + + align:start position:0% +Um, +okay. So, + + align:start position:0% +okay. So, + + + align:start position:0% +okay. So, +like I said, I'm kicking around the idea + + align:start position:0% +like I said, I'm kicking around the idea + + + align:start position:0% +like I said, I'm kicking around the idea +of uh scientific creativity being a + + align:start position:0% +of uh scientific creativity being a + + + align:start position:0% +of uh scientific creativity being a +personal expression of what the + + align:start position:0% +personal expression of what the + + + align:start position:0% +personal expression of what the +scientist believes the nature of the + + align:start position:0% +scientist believes the nature of the + + + align:start position:0% +scientist believes the nature of the +world is. Uh, so in other words, the + + align:start position:0% +world is. Uh, so in other words, the + + + align:start position:0% +world is. Uh, so in other words, the +metaphysics of the world. uh one example + + align:start position:0% +metaphysics of the world. uh one example + + + align:start position:0% +metaphysics of the world. uh one example +might be how + + align:start position:0% +might be how + + + align:start position:0% +might be how +uh early mechanics arose from capernicus + + align:start position:0% +uh early mechanics arose from capernicus + + + align:start position:0% +uh early mechanics arose from capernicus +to Kepler to Newton and then uh sort of + + align:start position:0% +to Kepler to Newton and then uh sort of + + + align:start position:0% +to Kepler to Newton and then uh sort of +in contradiction with Einstein by a + + align:start position:0% +in contradiction with Einstein by a + + + align:start position:0% +in contradiction with Einstein by a +statement of God's presence in the + + align:start position:0% +statement of God's presence in the + + + align:start position:0% +statement of God's presence in the +universe and that leading to harmonious + + align:start position:0% +universe and that leading to harmonious + + + align:start position:0% +universe and that leading to harmonious +relationships between uh the heavenly + + align:start position:0% +relationships between uh the heavenly + + + align:start position:0% +relationships between uh the heavenly +bodies + + align:start position:0% +bodies + + + align:start position:0% +bodies +and it was you know specifically a + + align:start position:0% +and it was you know specifically a + + + align:start position:0% +and it was you know specifically a +belief that uh if God is existent and + + align:start position:0% +belief that uh if God is existent and + + + align:start position:0% +belief that uh if God is existent and +present in the universe, then the + + align:start position:0% +present in the universe, then the + + + align:start position:0% +present in the universe, then the +relationships of objects in nature must + + align:start position:0% +relationships of objects in nature must + + + align:start position:0% +relationships of objects in nature must +be harmonious or beautiful or somehow + + align:start position:0% +be harmonious or beautiful or somehow + + + align:start position:0% +be harmonious or beautiful or somehow +representative of the great nature of + + align:start position:0% +representative of the great nature of + + + align:start position:0% +representative of the great nature of +God. And for example, Kepler + + align:start position:0% +God. And for example, Kepler + + + align:start position:0% +God. And for example, Kepler +uh was + + align:start position:0% +uh was + + + align:start position:0% +uh was +in part so pleased with his theory that + + align:start position:0% +in part so pleased with his theory that + + + align:start position:0% +in part so pleased with his theory that +uh gave the motions of the planets + + align:start position:0% +uh gave the motions of the planets + + + align:start position:0% +uh gave the motions of the planets +ellypoid form because it finally let him + + align:start position:0% +ellypoid form because it finally let him + + + align:start position:0% +ellypoid form because it finally let him +put the sun back at the center of the + + align:start position:0% +put the sun back at the center of the + + + align:start position:0% +put the sun back at the center of the +solar system where at at that time the + + align:start position:0% +solar system where at at that time the + + + align:start position:0% +solar system where at at that time the +universe which meant that the sun uh + + align:start position:0% +universe which meant that the sun uh + + + align:start position:0% +universe which meant that the sun uh +which he saw as the center of or the + + align:start position:0% +which he saw as the center of or the + + + align:start position:0% +which he saw as the center of or the +temple of God in some ways uh of the + + align:start position:0% +temple of God in some ways uh of the + + + align:start position:0% +temple of God in some ways uh of the +heavenly bodies was then in its rightful + + align:start position:0% +heavenly bodies was then in its rightful + + + align:start position:0% +heavenly bodies was then in its rightful +place in the universe. And that was + + align:start position:0% +place in the universe. And that was + + + align:start position:0% +place in the universe. And that was +beautiful to him and was something he + + align:start position:0% +beautiful to him and was something he + + + align:start position:0% +beautiful to him and was something he +actually + + align:start position:0% +actually + + + align:start position:0% +actually +uh + + align:start position:0% +uh + + + align:start position:0% +uh +used as or was an expression of what he + + align:start position:0% +used as or was an expression of what he + + + align:start position:0% +used as or was an expression of what he +believed in his science and that's + + align:start position:0% +believed in his science and that's + + + align:start position:0% +believed in his science and that's +something that guided him in creating + + align:start position:0% +something that guided him in creating + + + align:start position:0% +something that guided him in creating +the science. He was looking for a + + align:start position:0% +the science. He was looking for a + + + align:start position:0% +the science. He was looking for a +beautiful relationship between the + + align:start position:0% +beautiful relationship between the + + + align:start position:0% +beautiful relationship between the +heavenly bodies. Now it's balanced by + + align:start position:0% +heavenly bodies. Now it's balanced by + + + align:start position:0% +heavenly bodies. Now it's balanced by +the fact that uh the relationships have + + align:start position:0% +the fact that uh the relationships have + + + align:start position:0% +the fact that uh the relationships have +to be in accordance with observation. + + align:start position:0% +to be in accordance with observation. + + + align:start position:0% +to be in accordance with observation. +And so Kepler struggled with the fact + + align:start position:0% +And so Kepler struggled with the fact + + + align:start position:0% +And so Kepler struggled with the fact +that in fact the heavenly bodies were + + align:start position:0% +that in fact the heavenly bodies were + + + align:start position:0% +that in fact the heavenly bodies were +not did not have uh circular orbits but + + align:start position:0% +not did not have uh circular orbits but + + + align:start position:0% +not did not have uh circular orbits but +were ellip ellipses. But it's kind of + + align:start position:0% +were ellip ellipses. But it's kind of + + + align:start position:0% +were ellip ellipses. But it's kind of +interesting to see that when he did + + align:start position:0% +interesting to see that when he did + + + align:start position:0% +interesting to see that when he did +finally accept that they were ellipses, + + align:start position:0% +finally accept that they were ellipses, + + + align:start position:0% +finally accept that they were ellipses, +there were other beauties that he found + + align:start position:0% +there were other beauties that he found + + + align:start position:0% +there were other beauties that he found +to replace them which is that oh + + align:start position:0% +to replace them which is that oh + + + align:start position:0% +to replace them which is that oh +suddenly the sun is in the center of the + + align:start position:0% +suddenly the sun is in the center of the + + + align:start position:0% +suddenly the sun is in the center of the +the solar system. Uh Einstein kind of + + align:start position:0% +the solar system. Uh Einstein kind of + + + align:start position:0% +the solar system. Uh Einstein kind of +threw this out in some ways because he + + align:start position:0% +threw this out in some ways because he + + + align:start position:0% +threw this out in some ways because he +uh early on accepted uh the metaphysics + + align:start position:0% +uh early on accepted uh the metaphysics + + + align:start position:0% +uh early on accepted uh the metaphysics +of mock as in the uh speed of sound and + + align:start position:0% +of mock as in the uh speed of sound and + + + align:start position:0% +of mock as in the uh speed of sound and +who held that the primary + + align:start position:0% +who held that the primary + + + align:start position:0% +who held that the primary +uh + + align:start position:0% +uh + + + align:start position:0% +uh +I guess origin of knowledge was the + + align:start position:0% +I guess origin of knowledge was the + + + align:start position:0% +I guess origin of knowledge was the +senses and the senses uh told you + + align:start position:0% +senses and the senses uh told you + + + align:start position:0% +senses and the senses uh told you +nothing about what is in fact there. uh + + align:start position:0% +nothing about what is in fact there. uh + + + align:start position:0% +nothing about what is in fact there. uh +rather that all you could all you could + + align:start position:0% +rather that all you could all you could + + + align:start position:0% +rather that all you could all you could +build your your theories off of or your + + align:start position:0% +build your your theories off of or your + + + align:start position:0% +build your your theories off of or your +understanding of the of nature off of + + align:start position:0% +understanding of the of nature off of + + + align:start position:0% +understanding of the of nature off of +was were empirical measurements and that + + align:start position:0% +was were empirical measurements and that + + + align:start position:0% +was were empirical measurements and that +that they were observer centered and + + align:start position:0% +that they were observer centered and + + + align:start position:0% +that they were observer centered and +this fits nicely in with Einstein's + + align:start position:0% +this fits nicely in with Einstein's + + + align:start position:0% +this fits nicely in with Einstein's +theory of relativity because he what + + align:start position:0% +theory of relativity because he what + + + align:start position:0% +theory of relativity because he what +Einstein what the theory depends upon + + align:start position:0% +Einstein what the theory depends upon + + + align:start position:0% +Einstein what the theory depends upon +are the uh observable clocks and + + align:start position:0% +are the uh observable clocks and + + + align:start position:0% +are the uh observable clocks and +observable rulers that are dependent or + + align:start position:0% +observable rulers that are dependent or + + + align:start position:0% +observable rulers that are dependent or +whose measurements change based bas on + + align:start position:0% +whose measurements change based bas on + + + align:start position:0% +whose measurements change based bas on +where they are in space to the observer. + + align:start position:0% +where they are in space to the observer. + + + align:start position:0% +where they are in space to the observer. +And so in this way uh under the notion + + align:start position:0% +And so in this way uh under the notion + + + align:start position:0% +And so in this way uh under the notion +that the observer's measurements are + + align:start position:0% +that the observer's measurements are + + + align:start position:0% +that the observer's measurements are +primary, Einstein undercut the uh source + + align:start position:0% +primary, Einstein undercut the uh source + + + align:start position:0% +primary, Einstein undercut the uh source +of harmony in the universe from one god. + + align:start position:0% +of harmony in the universe from one god. + + + align:start position:0% +of harmony in the universe from one god. +It became observer oriented rather than + + align:start position:0% +It became observer oriented rather than + + + align:start position:0% +It became observer oriented rather than +uh some sort of absolute relationship + + align:start position:0% +uh some sort of absolute relationship + + + align:start position:0% +uh some sort of absolute relationship +between the different objects. + + align:start position:0% +between the different objects. + + + align:start position:0% +between the different objects. +Um so I have a few other examples but + + align:start position:0% +Um so I have a few other examples but + + + align:start position:0% +Um so I have a few other examples but +that's the basic idea in terms of uh how + + align:start position:0% +that's the basic idea in terms of uh how + + + align:start position:0% +that's the basic idea in terms of uh how +your worldview or your metaphysics on + + align:start position:0% +your worldview or your metaphysics on + + + align:start position:0% +your worldview or your metaphysics on +the nature of the universe are in fact + + align:start position:0% +the nature of the universe are in fact + + + align:start position:0% +the nature of the universe are in fact +or are what you express when you create + + align:start position:0% +or are what you express when you create + + + align:start position:0% +or are what you express when you create +a theory. Um when you create a theory + + align:start position:0% +a theory. Um when you create a theory + + + align:start position:0% +a theory. Um when you create a theory +what is the create element of creativity + + align:start position:0% +what is the create element of creativity + + + align:start position:0% +what is the create element of creativity +in this? + + align:start position:0% + + + + align:start position:0% + +what makes one theory more creative than + + align:start position:0% +what makes one theory more creative than + + + align:start position:0% +what makes one theory more creative than +another. + + align:start position:0% + + + + align:start position:0% + +So in his book the structure of + + align:start position:0% +So in his book the structure of + + + align:start position:0% +So in his book the structure of +scientific revolutions draws a + + align:start position:0% +scientific revolutions draws a + + + align:start position:0% +scientific revolutions draws a +distinction between extraordinary and + + align:start position:0% +distinction between extraordinary and + + + align:start position:0% +distinction between extraordinary and +normal science uh where extraordinary + + align:start position:0% +normal science uh where extraordinary + + + align:start position:0% +normal science uh where extraordinary +science creates uh a + + align:start position:0% +science creates uh a + + + align:start position:0% +science creates uh a +sort of new + + align:start position:0% +sort of new + + + align:start position:0% +sort of new +paradigm paradigm. Yeah. uh that is no + + align:start position:0% +paradigm paradigm. Yeah. uh that is no + + + align:start position:0% +paradigm paradigm. Yeah. uh that is no +is not commensurable is not logically + + align:start position:0% +is not commensurable is not logically + + + align:start position:0% +is not commensurable is not logically +connectable perfectly back to the + + align:start position:0% +connectable perfectly back to the + + + align:start position:0% +connectable perfectly back to the +previous paradigm. So going from + + align:start position:0% +previous paradigm. So going from + + + align:start position:0% +previous paradigm. So going from +classical mechanics to quantum mechanics + + align:start position:0% +classical mechanics to quantum mechanics + + + align:start position:0% +classical mechanics to quantum mechanics +would be a paradigm shift and and that + + align:start position:0% +would be a paradigm shift and and that + + + align:start position:0% +would be a paradigm shift and and that +is that is extraordinary science now. So + + align:start position:0% +is that is extraordinary science now. So + + + align:start position:0% +is that is extraordinary science now. So +um so that that so in extraordinary + + align:start position:0% +um so that that so in extraordinary + + + align:start position:0% +um so that that so in extraordinary +science the creativity is exactly the + + align:start position:0% +science the creativity is exactly the + + + align:start position:0% +science the creativity is exactly the +expression of a new metaphysics a new um + + align:start position:0% +expression of a new metaphysics a new um + + + align:start position:0% +expression of a new metaphysics a new um +well a new perspective right and but is + + align:start position:0% +well a new perspective right and but is + + + align:start position:0% +well a new perspective right and but is +that the meaning of creativity or is + + align:start position:0% +that the meaning of creativity or is + + + align:start position:0% +that the meaning of creativity or is +there creativity in normal science so in + + align:start position:0% +there creativity in normal science so in + + + align:start position:0% +there creativity in normal science so in +normal science I think the creativity is + + align:start position:0% +normal science I think the creativity is + + + align:start position:0% +normal science I think the creativity is +different um and I haven't delved into + + align:start position:0% +different um and I haven't delved into + + + align:start position:0% +different um and I haven't delved into +this part as deeply but uh the idea I'm + + align:start position:0% +this part as deeply but uh the idea I'm + + + align:start position:0% +this part as deeply but uh the idea I'm +playing around with is in fact that uh + + align:start position:0% +playing around with is in fact that uh + + + align:start position:0% +playing around with is in fact that uh +the I mean what what calls that + + align:start position:0% +the I mean what what calls that + + + align:start position:0% +the I mean what what calls that +normal science is basically problem + + align:start position:0% +normal science is basically problem + + + align:start position:0% +normal science is basically problem +solving. uh you have some paradigm, you + + align:start position:0% +solving. uh you have some paradigm, you + + + align:start position:0% +solving. uh you have some paradigm, you +have a problem that because you accept + + align:start position:0% +have a problem that because you accept + + + align:start position:0% +have a problem that because you accept +the paradigm, you know must be solvable. + + align:start position:0% +the paradigm, you know must be solvable. + + + align:start position:0% +the paradigm, you know must be solvable. +So therefore, you must solve the problem + + align:start position:0% +So therefore, you must solve the problem + + + align:start position:0% +So therefore, you must solve the problem +and if you don't, it's your failure, not + + align:start position:0% +and if you don't, it's your failure, not + + + align:start position:0% +and if you don't, it's your failure, not +the paradigms. Now, of course, that + + align:start position:0% +the paradigms. Now, of course, that + + + align:start position:0% +the paradigms. Now, of course, that +breaks down when you actually get to the + + align:start position:0% +breaks down when you actually get to the + + + align:start position:0% +breaks down when you actually get to the +point where the paradigm really does + + align:start position:0% +point where the paradigm really does + + + align:start position:0% +point where the paradigm really does +fail. But if you're working within the + + align:start position:0% +fail. But if you're working within the + + + align:start position:0% +fail. But if you're working within the +paradigm, then you must be able to solve + + align:start position:0% +paradigm, then you must be able to solve + + + align:start position:0% +paradigm, then you must be able to solve +the problem. And + + align:start position:0% +the problem. And + + + align:start position:0% +the problem. And +I think the creativity there is to find + + align:start position:0% +I think the creativity there is to find + + + align:start position:0% +I think the creativity there is to find +how the + + align:start position:0% +how the + + + align:start position:0% +how the +structure of the solution fits with the + + align:start position:0% +structure of the solution fits with the + + + align:start position:0% +structure of the solution fits with the +structure of the paradigm. Uh which in + + align:start position:0% +structure of the paradigm. Uh which in + + + align:start position:0% +structure of the paradigm. Uh which in +some in some ways is a a design problem. + + align:start position:0% +some in some ways is a a design problem. + + + align:start position:0% +some in some ways is a a design problem. +Uh you're looking to uh on some level + + align:start position:0% +Uh you're looking to uh on some level + + + align:start position:0% +Uh you're looking to uh on some level +construct consciously and on some level + + align:start position:0% +construct consciously and on some level + + + align:start position:0% +construct consciously and on some level +uh intuitively understand the uh correct + + align:start position:0% +uh intuitively understand the uh correct + + + align:start position:0% +uh intuitively understand the uh correct +design that fits the given structure of + + align:start position:0% +design that fits the given structure of + + + align:start position:0% +design that fits the given structure of +the theory. Um + + align:start position:0% +the theory. Um + + + align:start position:0% +the theory. Um +what I would sort of throw out there + + align:start position:0% +what I would sort of throw out there + + + align:start position:0% +what I would sort of throw out there +which may be nonsense but + + align:start position:0% +which may be nonsense but + + + align:start position:0% +which may be nonsense but +um is that what is beautiful about + + align:start position:0% +um is that what is beautiful about + + + align:start position:0% +um is that what is beautiful about +problem solving is exactly how it fits + + align:start position:0% +problem solving is exactly how it fits + + + align:start position:0% +problem solving is exactly how it fits +the metaphysics of the paradigm. So that + + align:start position:0% +the metaphysics of the paradigm. So that + + + align:start position:0% +the metaphysics of the paradigm. So that +if it's an expression of the basic + + align:start position:0% +if it's an expression of the basic + + + align:start position:0% +if it's an expression of the basic +perspectives such as uh God is the + + align:start position:0% +perspectives such as uh God is the + + + align:start position:0% +perspectives such as uh God is the +origin of harmony in the heavenly bodies + + align:start position:0% +origin of harmony in the heavenly bodies + + + align:start position:0% +origin of harmony in the heavenly bodies +then that is a beautiful solution in + + align:start position:0% +then that is a beautiful solution in + + + align:start position:0% +then that is a beautiful solution in +science. + + align:start position:0% +science. + + + align:start position:0% +science. +Now that may not be the the same uh + + align:start position:0% +Now that may not be the the same uh + + + align:start position:0% +Now that may not be the the same uh +aesthetic pleasure or beauty that we + + align:start position:0% +aesthetic pleasure or beauty that we + + + align:start position:0% +aesthetic pleasure or beauty that we +brought up earlier in terms of doing lab + + align:start position:0% +brought up earlier in terms of doing lab + + + align:start position:0% +brought up earlier in terms of doing lab +work but in terms of a theoretical uh + + align:start position:0% +work but in terms of a theoretical uh + + + align:start position:0% +work but in terms of a theoretical uh +origin that would be + + align:start position:0% +origin that would be + + + align:start position:0% +origin that would be +a possible explanation for what is + + align:start position:0% +a possible explanation for what is + + + align:start position:0% +a possible explanation for what is +beautiful in science. + + align:start position:0% +beautiful in science. + + + align:start position:0% +beautiful in science. +You can think it's totally nonsense. + + align:start position:0% + + + + align:start position:0% + +You look like you're thinking about + + align:start position:0% +You look like you're thinking about + + + align:start position:0% +You look like you're thinking about +something. Is that true? No. Okay. + + align:start position:0% + + + + align:start position:0% + +Should we go on to another paper? + + align:start position:0% +Should we go on to another paper? + + + align:start position:0% +Should we go on to another paper? +Another This This is the basis of your + + align:start position:0% +Another This This is the basis of your + + + align:start position:0% +Another This This is the basis of your +paper, right? Yeah. My paper is going to + + align:start position:0% +paper, right? Yeah. My paper is going to + + + align:start position:0% +paper, right? Yeah. My paper is going to +be a subset of that because How far is + + align:start position:0% +be a subset of that because How far is + + + align:start position:0% +be a subset of that because How far is +it to being being complete? Not far + + align:start position:0% +it to being being complete? Not far + + + align:start position:0% +it to being being complete? Not far +enough. + + align:start position:0% +enough. + + + align:start position:0% +enough. +It It's too large. I'm going to take a + + align:start position:0% +It It's too large. I'm going to take a + + + align:start position:0% +It It's too large. I'm going to take a +small part of it. Well, we'll we'll talk + + align:start position:0% +small part of it. Well, we'll we'll talk + + + align:start position:0% +small part of it. Well, we'll we'll talk +about that later on about when the + + align:start position:0% +about that later on about when the + + + align:start position:0% +about that later on about when the +papers are going to be handed in and + + align:start position:0% +papers are going to be handed in and + + + align:start position:0% +papers are going to be handed in and +just what state they're in. Um, + + align:start position:0% +just what state they're in. Um, + + + align:start position:0% +just what state they're in. Um, +which way should we go? Eric, I mean, + + align:start position:0% +which way should we go? Eric, I mean, + + + align:start position:0% +which way should we go? Eric, I mean, +um, Alec, are you ready? Sure, why not? + + align:start position:0% +um, Alec, are you ready? Sure, why not? + + + align:start position:0% +um, Alec, are you ready? Sure, why not? +Uh, okay. So, I'm I'm kind of doing uh + + align:start position:0% +Uh, okay. So, I'm I'm kind of doing uh + + + align:start position:0% +Uh, okay. So, I'm I'm kind of doing uh +kind of like what I talked about last + + align:start position:0% +kind of like what I talked about last + + + align:start position:0% +kind of like what I talked about last +week where um I'm interested in looking + + align:start position:0% +week where um I'm interested in looking + + + align:start position:0% +week where um I'm interested in looking +at uh the idea of free will and uh + + align:start position:0% +at uh the idea of free will and uh + + + align:start position:0% +at uh the idea of free will and uh +determinism. And actually I guess we + + align:start position:0% +determinism. And actually I guess we + + + align:start position:0% +determinism. And actually I guess we +talked about this briefly earlier uh + + align:start position:0% +talked about this briefly earlier uh + + + align:start position:0% +talked about this briefly earlier uh +today. Um and what the implications are + + align:start position:0% +today. Um and what the implications are + + + align:start position:0% +today. Um and what the implications are +uh for creativity where if well for + + align:start position:0% +uh for creativity where if well for + + + align:start position:0% +uh for creativity where if well for +example if you look at it in one way + + align:start position:0% +example if you look at it in one way + + + align:start position:0% +example if you look at it in one way +from in the sort of uh uh mind body + + align:start position:0% +from in the sort of uh uh mind body + + + align:start position:0% +from in the sort of uh uh mind body +problem. If creativity is something that + + align:start position:0% +problem. If creativity is something that + + + align:start position:0% +problem. If creativity is something that +arises out of mind and mind is something + + align:start position:0% +arises out of mind and mind is something + + + align:start position:0% +arises out of mind and mind is something +that arises out of the brain and the + + align:start position:0% +that arises out of the brain and the + + + align:start position:0% +that arises out of the brain and the +brain is governed by physical laws um in + + align:start position:0% +brain is governed by physical laws um in + + + align:start position:0% +brain is governed by physical laws um in +some deterministic + + align:start position:0% +some deterministic + + + align:start position:0% +some deterministic +nature of or of some deterministic + + align:start position:0% +nature of or of some deterministic + + + align:start position:0% +nature of or of some deterministic +nature rather uh then is creativity + + align:start position:0% +nature rather uh then is creativity + + + align:start position:0% +nature rather uh then is creativity +itself you know deterministic i.e. If + + align:start position:0% +itself you know deterministic i.e. If + + + align:start position:0% +itself you know deterministic i.e. If +you could know everything uh about the + + align:start position:0% +you could know everything uh about the + + + align:start position:0% +you could know everything uh about the +you know all the states of all the + + align:start position:0% +you know all the states of all the + + + align:start position:0% +you know all the states of all the +particles and everything in the early + + align:start position:0% +particles and everything in the early + + + align:start position:0% +particles and everything in the early +universe and what they were doing at any + + align:start position:0% +universe and what they were doing at any + + + align:start position:0% +universe and what they were doing at any +given moment you would be able to sort + + align:start position:0% +given moment you would be able to sort + + + align:start position:0% +given moment you would be able to sort +of uh calculate out all creativity that + + align:start position:0% +of uh calculate out all creativity that + + + align:start position:0% +of uh calculate out all creativity that +would happen um from that point forward + + align:start position:0% +would happen um from that point forward + + + align:start position:0% +would happen um from that point forward +or sort of back calculate anything that + + align:start position:0% +or sort of back calculate anything that + + + align:start position:0% +or sort of back calculate anything that +had happened before that. um is + + align:start position:0% +had happened before that. um is + + + align:start position:0% +had happened before that. um is +creativity truly creative or is it + + align:start position:0% +creativity truly creative or is it + + + align:start position:0% +creativity truly creative or is it +simply something that uh + + align:start position:0% +simply something that uh + + + align:start position:0% +simply something that uh +follows from physical laws and it's it's + + align:start position:0% +follows from physical laws and it's it's + + + align:start position:0% +follows from physical laws and it's it's +its sort of independent nature is an + + align:start position:0% +its sort of independent nature is an + + + align:start position:0% +its sort of independent nature is an +illusion kind of thing. So um there is + + align:start position:0% +illusion kind of thing. So um there is + + + align:start position:0% +illusion kind of thing. So um there is +for you the question it involves a + + align:start position:0% +for you the question it involves a + + + align:start position:0% +for you the question it involves a +paradox maybe it's a paradox that um if + + align:start position:0% +paradox maybe it's a paradox that um if + + + align:start position:0% +paradox maybe it's a paradox that um if +something is really creative then it's + + align:start position:0% +something is really creative then it's + + + align:start position:0% +something is really creative then it's +not creative because it carries out + + align:start position:0% +not creative because it carries out + + + align:start position:0% +not creative because it carries out +those laws. Right. Right. So the + + align:start position:0% +those laws. Right. Right. So the + + + align:start position:0% +those laws. Right. Right. So the +question is is there anything that is + + align:start position:0% +question is is there anything that is + + + align:start position:0% +question is is there anything that is +truly paradoxical? That's your + + align:start position:0% +truly paradoxical? That's your + + + align:start position:0% +truly paradoxical? That's your +fundamental question. Am I right? Uh + + align:start position:0% +fundamental question. Am I right? Uh + + + align:start position:0% +fundamental question. Am I right? Uh +how do you mean in terms of what you + + align:start position:0% +how do you mean in terms of what you + + + align:start position:0% +how do you mean in terms of what you +were just now saying? I wasn't adding + + align:start position:0% +were just now saying? I wasn't adding + + + align:start position:0% +were just now saying? I wasn't adding +anything. I was trying to reformulate + + align:start position:0% +anything. I was trying to reformulate + + + align:start position:0% +anything. I was trying to reformulate +it. Uh where does where does where's the + + align:start position:0% +it. Uh where does where does where's the + + + align:start position:0% +it. Uh where does where does where's the +paradoxical come in? That to be creative + + align:start position:0% +paradoxical come in? That to be creative + + + align:start position:0% +paradoxical come in? That to be creative +seems to be not derivative merely from + + align:start position:0% +seems to be not derivative merely from + + + align:start position:0% +seems to be not derivative merely from +pre-established laws. then we would say, + + align:start position:0% +pre-established laws. then we would say, + + + align:start position:0% +pre-established laws. then we would say, +"Oh, no. It's not create it's not really + + align:start position:0% +"Oh, no. It's not create it's not really + + + align:start position:0% +"Oh, no. It's not create it's not really +creative because it's been determined." + + align:start position:0% +creative because it's been determined." + + + align:start position:0% +creative because it's been determined." +Well, no, not not so much in that sense. + + align:start position:0% +Well, no, not not so much in that sense. + + + align:start position:0% +Well, no, not not so much in that sense. +I mean, it would it would require a + + align:start position:0% +I mean, it would it would require a + + + align:start position:0% +I mean, it would it would require a +little bit of a redefinition of the + + align:start position:0% +little bit of a redefinition of the + + + align:start position:0% +little bit of a redefinition of the +understanding of creativity, but just + + align:start position:0% +understanding of creativity, but just + + + align:start position:0% +understanding of creativity, but just +just because, you know, creativity + + align:start position:0% +just because, you know, creativity + + + align:start position:0% +just because, you know, creativity +doesn't actually come out of some + + align:start position:0% +doesn't actually come out of some + + + align:start position:0% +doesn't actually come out of some +something external to the physical + + align:start position:0% +something external to the physical + + + align:start position:0% +something external to the physical +world. Doesn't mean that it's anything + + align:start position:0% +world. Doesn't mean that it's anything + + + align:start position:0% +world. Doesn't mean that it's anything +different. It's just, you know, + + align:start position:0% +different. It's just, you know, + + + align:start position:0% +different. It's just, you know, +understanding that at its most + + align:start position:0% +understanding that at its most + + + align:start position:0% +understanding that at its most +fundamental level, it's that. Um now one + + align:start position:0% +fundamental level, it's that. Um now one + + + align:start position:0% +fundamental level, it's that. Um now one +of the things I'm I'm thinking along + + align:start position:0% +of the things I'm I'm thinking along + + + align:start position:0% +of the things I'm I'm thinking along +these lines is h how it has to do with + + align:start position:0% +these lines is h how it has to do with + + + align:start position:0% +these lines is h how it has to do with +free will um where the two would sort of + + align:start position:0% +free will um where the two would sort of + + + align:start position:0% +free will um where the two would sort of +seem to be linked um in that if + + align:start position:0% +seem to be linked um in that if + + + align:start position:0% +seem to be linked um in that if +creativity is truly creative in in the + + align:start position:0% +creativity is truly creative in in the + + + align:start position:0% +creativity is truly creative in in the +original sense then there's some element + + align:start position:0% +original sense then there's some element + + + align:start position:0% +original sense then there's some element +of free will involved um if there is no + + align:start position:0% +of free will involved um if there is no + + + align:start position:0% +of free will involved um if there is no +free will there is no you know + + align:start position:0% +free will there is no you know + + + align:start position:0% +free will there is no you know +creativity in that sense and the + + align:start position:0% +creativity in that sense and the + + + align:start position:0% +creativity in that sense and the +interesting thing about it is that if + + align:start position:0% +interesting thing about it is that if + + + align:start position:0% +interesting thing about it is that if +you have a totally deter deterministic + + align:start position:0% +you have a totally deter deterministic + + + align:start position:0% +you have a totally deter deterministic +universe and uh and again this is I + + align:start position:0% +universe and uh and again this is I + + + align:start position:0% +universe and uh and again this is I +briefly mentioned this last week. Uh if + + align:start position:0% +briefly mentioned this last week. Uh if + + + align:start position:0% +briefly mentioned this last week. Uh if +you have a totally deterministic + + align:start position:0% +you have a totally deterministic + + + align:start position:0% +you have a totally deterministic +universe and you know the human mind is + + align:start position:0% +universe and you know the human mind is + + + align:start position:0% +universe and you know the human mind is +simply just this sort of big complex + + align:start position:0% +simply just this sort of big complex + + + align:start position:0% +simply just this sort of big complex +calculator uh where if you know what's + + align:start position:0% +calculator uh where if you know what's + + + align:start position:0% +calculator uh where if you know what's +going on with all the elements inside + + align:start position:0% +going on with all the elements inside + + + align:start position:0% +going on with all the elements inside +it, you can figure out what it's going + + align:start position:0% +it, you can figure out what it's going + + + align:start position:0% +it, you can figure out what it's going +to do. Um you know does that mean that + + align:start position:0% +to do. Um you know does that mean that + + + align:start position:0% +to do. Um you know does that mean that +there's no free will? Uh but the trick + + align:start position:0% +there's no free will? Uh but the trick + + + align:start position:0% +there's no free will? Uh but the trick +to that is is that uh such a system can + + align:start position:0% +to that is is that uh such a system can + + + align:start position:0% +to that is is that uh such a system can +have a set of beliefs independent of + + align:start position:0% +have a set of beliefs independent of + + + align:start position:0% +have a set of beliefs independent of +free will. A system can have a belief + + align:start position:0% +free will. A system can have a belief + + + align:start position:0% +free will. A system can have a belief +about things. uh for example a + + align:start position:0% +about things. uh for example a + + + align:start position:0% +about things. uh for example a +thermostat can believe that the + + align:start position:0% +thermostat can believe that the + + + align:start position:0% +thermostat can believe that the +temperature in the room is something it + + align:start position:0% +temperature in the room is something it + + + align:start position:0% +temperature in the room is something it +has nothing to do with free will and if + + align:start position:0% +has nothing to do with free will and if + + + align:start position:0% +has nothing to do with free will and if +the the system that is the human brain + + align:start position:0% +the the system that is the human brain + + + align:start position:0% +the the system that is the human brain +or the human mind um if that system + + align:start position:0% +or the human mind um if that system + + + align:start position:0% +or the human mind um if that system +actually itself has the belief in free + + align:start position:0% +actually itself has the belief in free + + + align:start position:0% +actually itself has the belief in free +will it has the belief that it has the + + align:start position:0% +will it has the belief that it has the + + + align:start position:0% +will it has the belief that it has the +capacity to make these decisions that + + align:start position:0% +capacity to make these decisions that + + + align:start position:0% +capacity to make these decisions that +actually changes the calculus that + + align:start position:0% +actually changes the calculus that + + + align:start position:0% +actually changes the calculus that +occurs um uh when that system you know + + align:start position:0% +occurs um uh when that system you know + + + align:start position:0% +occurs um uh when that system you know +calculates what to do next or decides + + align:start position:0% +calculates what to do next or decides + + + align:start position:0% +calculates what to do next or decides +what to do um depending on whether or + + align:start position:0% +what to do um depending on whether or + + + align:start position:0% +what to do um depending on whether or +not it believes that it has the capacity + + align:start position:0% +not it believes that it has the capacity + + + align:start position:0% +not it believes that it has the capacity +for free Well, but aren't these two + + align:start position:0% +for free Well, but aren't these two + + + align:start position:0% +for free Well, but aren't these two +different questions? One about the + + align:start position:0% +different questions? One about the + + + align:start position:0% +different questions? One about the +nature of creativity and second the + + align:start position:0% +nature of creativity and second the + + + align:start position:0% +nature of creativity and second the +question of whether there is free will. + + align:start position:0% +question of whether there is free will. + + + align:start position:0% +question of whether there is free will. +Uh because even if there is free will, + + align:start position:0% +Uh because even if there is free will, + + + align:start position:0% +Uh because even if there is free will, +there might be a world in which there is + + align:start position:0% +there might be a world in which there is + + + align:start position:0% +there might be a world in which there is +no creativity. No real that's called + + align:start position:0% +no creativity. No real that's called + + + align:start position:0% +no creativity. No real that's called +true creativity. That's true. But and + + align:start position:0% +true creativity. That's true. But and + + + align:start position:0% +true creativity. That's true. But and +second, if even if the world is + + align:start position:0% +second, if even if the world is + + + align:start position:0% +second, if even if the world is +determined, we could say in in some + + align:start position:0% +determined, we could say in in some + + + align:start position:0% +determined, we could say in in some +areas of determin determination there is + + align:start position:0% +areas of determin determination there is + + + align:start position:0% +areas of determin determination there is +creativity and others not. So maybe the + + align:start position:0% +creativity and others not. So maybe the + + + align:start position:0% +creativity and others not. So maybe the +two problems are but I think unrelated I + + align:start position:0% +two problems are but I think unrelated I + + + align:start position:0% +two problems are but I think unrelated I +mean the way I see it I think free will + + align:start position:0% +mean the way I see it I think free will + + + align:start position:0% +mean the way I see it I think free will +is a necessary condition for I guess + + align:start position:0% +is a necessary condition for I guess + + + align:start position:0% +is a necessary condition for I guess +what we'll call true creativity in an + + align:start position:0% +what we'll call true creativity in an + + + align:start position:0% +what we'll call true creativity in an +original sense where if there is no free + + align:start position:0% +original sense where if there is no free + + + align:start position:0% +original sense where if there is no free +will then you know what would the + + align:start position:0% +will then you know what would the + + + align:start position:0% +will then you know what would the +creativity be coming out of um if if you + + align:start position:0% +creativity be coming out of um if if you + + + align:start position:0% +creativity be coming out of um if if you +have this true creativity wherein it is + + align:start position:0% +have this true creativity wherein it is + + + align:start position:0% +have this true creativity wherein it is +something coming in external uh from + + align:start position:0% +something coming in external uh from + + + align:start position:0% +something coming in external uh from +from external to the system then that in + + align:start position:0% +from external to the system then that in + + + align:start position:0% +from external to the system then that in +itself could be considered a form of + + align:start position:0% +itself could be considered a form of + + + align:start position:0% +itself could be considered a form of +free will and so if there is no free + + align:start position:0% +free will and so if there is no free + + + align:start position:0% +free will and so if there is no free +will there can be no true creativity in + + align:start position:0% +will there can be no true creativity in + + + align:start position:0% +will there can be no true creativity in +that but that's because of the + + align:start position:0% +that but that's because of the + + + align:start position:0% +that but that's because of the +definition you're given giving to the + + align:start position:0% +definition you're given giving to the + + + align:start position:0% +definition you're given giving to the +word true in ordinary language someone + + align:start position:0% +word true in ordinary language someone + + + align:start position:0% +word true in ordinary language someone +might say of of Picasso he really was + + align:start position:0% +might say of of Picasso he really was + + + align:start position:0% +might say of of Picasso he really was +very creative look at all of these + + align:start position:0% +very creative look at all of these + + + align:start position:0% +very creative look at all of these +different stages and different works + + align:start position:0% +different stages and different works + + + align:start position:0% +different stages and different works +that he produced um and um this that and + + align:start position:0% +that he produced um and um this that and + + + align:start position:0% +that he produced um and um this that and +someone would say yes that really is an + + align:start position:0% +someone would say yes that really is an + + + align:start position:0% +someone would say yes that really is an +example of creativity but it would apply + + align:start position:0% +example of creativity but it would apply + + + align:start position:0% +example of creativity but it would apply +even whether the world is free or + + align:start position:0% +even whether the world is free or + + + align:start position:0% +even whether the world is free or +determined that seems to be a + + align:start position:0% +determined that seems to be a + + + align:start position:0% +determined that seems to be a +metaphysical question of a different + + align:start position:0% +metaphysical question of a different + + + align:start position:0% +metaphysical question of a different +sort + + align:start position:0% +sort + + + align:start position:0% +sort +Unless you defy true creativity as not + + align:start position:0% +Unless you defy true creativity as not + + + align:start position:0% +Unless you defy true creativity as not +being deterministic. + + align:start position:0% +being deterministic. + + + align:start position:0% +being deterministic. +Um, well, yeah. I mean, I mean, that's + + align:start position:0% +Um, well, yeah. I mean, I mean, that's + + + align:start position:0% +Um, well, yeah. I mean, I mean, that's +that's sort of what I'm getting at is + + align:start position:0% +that's sort of what I'm getting at is + + + align:start position:0% +that's sort of what I'm getting at is +trying to explore, you know, I mean, I + + align:start position:0% +trying to explore, you know, I mean, I + + + align:start position:0% +trying to explore, you know, I mean, I +don't I don't think this this + + align:start position:0% +don't I don't think this this + + + align:start position:0% +don't I don't think this this +necessarily + + align:start position:0% +necessarily + + + align:start position:0% +necessarily +uh + + align:start position:0% +uh + + + align:start position:0% +uh +it doesn't, you know, it doesn't change + + align:start position:0% +it doesn't, you know, it doesn't change + + + align:start position:0% +it doesn't, you know, it doesn't change +the fact that we'll look at something + + align:start position:0% +the fact that we'll look at something + + + align:start position:0% +the fact that we'll look at something +that Picasso did or whatever and say, + + align:start position:0% +that Picasso did or whatever and say, + + + align:start position:0% +that Picasso did or whatever and say, +"Yes, that's creative." But then the + + align:start position:0% +"Yes, that's creative." But then the + + + align:start position:0% +"Yes, that's creative." But then the +question is uh is that something that + + align:start position:0% +question is uh is that something that + + + align:start position:0% +question is uh is that something that +simply arose because of the physical + + align:start position:0% +simply arose because of the physical + + + align:start position:0% +simply arose because of the physical +nature of his brain at that time in that + + align:start position:0% +nature of his brain at that time in that + + + align:start position:0% +nature of his brain at that time in that +environment or is it did it come from + + align:start position:0% +environment or is it did it come from + + + align:start position:0% +environment or is it did it come from +something external to the whole system? + + align:start position:0% +something external to the whole system? + + + align:start position:0% +something external to the whole system? +Um, and I think I think again though + + align:start position:0% +Um, and I think I think again though + + + align:start position:0% +Um, and I think I think again though +that uh there and I I haven't fully + + align:start position:0% +that uh there and I I haven't fully + + + align:start position:0% +that uh there and I I haven't fully +worked out this part of my argument yet, + + align:start position:0% +worked out this part of my argument yet, + + + align:start position:0% +worked out this part of my argument yet, +but um as I argued for the thing of free + + align:start position:0% +but um as I argued for the thing of free + + + align:start position:0% +but um as I argued for the thing of free +will where if if the system of the human + + align:start position:0% +will where if if the system of the human + + + align:start position:0% +will where if if the system of the human +brain uh or mind does in fact believe + + align:start position:0% +brain uh or mind does in fact believe + + + align:start position:0% +brain uh or mind does in fact believe +that it has free will that actually + + align:start position:0% +that it has free will that actually + + + align:start position:0% +that it has free will that actually +changes what it will do so that it will + + align:start position:0% +changes what it will do so that it will + + + align:start position:0% +changes what it will do so that it will +behave as though it has uh some sort of + + align:start position:0% +behave as though it has uh some sort of + + + align:start position:0% +behave as though it has uh some sort of +free will. I think a similar argument + + align:start position:0% +free will. I think a similar argument + + + align:start position:0% +free will. I think a similar argument +may apply to creativity where if uh + + align:start position:0% +may apply to creativity where if uh + + + align:start position:0% +may apply to creativity where if uh +someone believes if if if if one of the + + align:start position:0% +someone believes if if if if one of the + + + align:start position:0% +someone believes if if if if one of the +if if a brain or system believes it that + + align:start position:0% +if if a brain or system believes it that + + + align:start position:0% +if if a brain or system believes it that +it is creative that it has capacity for + + align:start position:0% +it is creative that it has capacity for + + + align:start position:0% +it is creative that it has capacity for +creativity that that actually changes um + + align:start position:0% +creativity that that actually changes um + + + align:start position:0% +creativity that that actually changes um +what that system will produce and you + + align:start position:0% +what that system will produce and you + + + align:start position:0% +what that system will produce and you +know therein sort of paradoxically + + align:start position:0% +know therein sort of paradoxically + + + align:start position:0% +know therein sort of paradoxically +creates uh the creative process out of + + align:start position:0% +creates uh the creative process out of + + + align:start position:0% +creates uh the creative process out of +that. But somebody might believe that he + + align:start position:0% +that. But somebody might believe that he + + + align:start position:0% +that. But somebody might believe that he +has no free will and yet go on and be + + align:start position:0% +has no free will and yet go on and be + + + align:start position:0% +has no free will and yet go on and be +very creative. What would you say to + + align:start position:0% +very creative. What would you say to + + + align:start position:0% +very creative. What would you say to +him? Oh, you're deliluding yourself + + align:start position:0% +him? Oh, you're deliluding yourself + + + align:start position:0% +him? Oh, you're deliluding yourself +because uh you're contradicting yourself + + align:start position:0% +because uh you're contradicting yourself + + + align:start position:0% +because uh you're contradicting yourself +because if there is you have no free + + align:start position:0% +because if there is you have no free + + + align:start position:0% +because if there is you have no free +will, then how can you be creative? + + align:start position:0% +will, then how can you be creative? + + + align:start position:0% +will, then how can you be creative? +You're just doing things that come out + + align:start position:0% +You're just doing things that come out + + + align:start position:0% +You're just doing things that come out +of you. But every to the rest of us + + align:start position:0% +of you. But every to the rest of us + + + align:start position:0% +of you. But every to the rest of us +there these astonishing things would be + + align:start position:0% +there these astonishing things would be + + + align:start position:0% +there these astonishing things would be +what we mean by creativity. Yes. But + + align:start position:0% +what we mean by creativity. Yes. But + + + align:start position:0% +what we mean by creativity. Yes. But +those those predetermined. Yeah. They + + align:start position:0% +those those predetermined. Yeah. They + + + align:start position:0% +those those predetermined. Yeah. They +were all predetermined is what the + + align:start position:0% +were all predetermined is what the + + + align:start position:0% +were all predetermined is what the +argument would be. If if you know if + + align:start position:0% +argument would be. If if you know if + + + align:start position:0% +argument would be. If if you know if +this free will if this this source of uh + + align:start position:0% +this free will if this this source of uh + + + align:start position:0% +this free will if this this source of uh +mental things external to physical + + align:start position:0% +mental things external to physical + + + align:start position:0% +mental things external to physical +reality exists um that's one thing. If + + align:start position:0% +reality exists um that's one thing. If + + + align:start position:0% +reality exists um that's one thing. If +it doesn't exist then all of these + + align:start position:0% +it doesn't exist then all of these + + + align:start position:0% +it doesn't exist then all of these +things uh follow from physical laws. Uh + + align:start position:0% +things uh follow from physical laws. Uh + + + align:start position:0% +things uh follow from physical laws. Uh +unless you don't necessarily believe in + + align:start position:0% +unless you don't necessarily believe in + + + align:start position:0% +unless you don't necessarily believe in +a deterministic universe which is a bit + + align:start position:0% +a deterministic universe which is a bit + + + align:start position:0% +a deterministic universe which is a bit +more of a problem for physics. Um, + + align:start position:0% +more of a problem for physics. Um, + + + align:start position:0% +more of a problem for physics. Um, +quantum mechanics does open the door to + + align:start position:0% +quantum mechanics does open the door to + + + align:start position:0% +quantum mechanics does open the door to +possibility of a universe that's not + + align:start position:0% +possibility of a universe that's not + + + align:start position:0% +possibility of a universe that's not +deterministic. Um, but you know, again, + + align:start position:0% +deterministic. Um, but you know, again, + + + align:start position:0% +deterministic. Um, but you know, again, +that's sort of a bit of a physical + + align:start position:0% +that's sort of a bit of a physical + + + align:start position:0% +that's sort of a bit of a physical +question. Could we take a break at this + + align:start position:0% +question. Could we take a break at this + + + align:start position:0% +question. Could we take a break at this +point? I'd like to continue with Eric + + align:start position:0% +point? I'd like to continue with Eric + + + align:start position:0% +point? I'd like to continue with Eric +and the rest of you. Now, we've got one + + align:start position:0% +and the rest of you. Now, we've got one + + + align:start position:0% +and the rest of you. Now, we've got one +and a half papers discussed and I do + + align:start position:0% +and a half papers discussed and I do + + + align:start position:0% +and a half papers discussed and I do +want to hear from all of you, but could + + align:start position:0% +want to hear from all of you, but could + + + align:start position:0% +want to hear from all of you, but could +we take a short break, please? + + align:start position:0% + + + + align:start position:0% + +All right. Um, why don't you start? + + align:start position:0% +All right. Um, why don't you start? + + + align:start position:0% +All right. Um, why don't you start? +Okay, where are we? Um, tell me how far + + align:start position:0% +Okay, where are we? Um, tell me how far + + + align:start position:0% +Okay, where are we? Um, tell me how far +along the paper is. Uh, it's getting + + align:start position:0% +along the paper is. Uh, it's getting + + + align:start position:0% +along the paper is. Uh, it's getting +there. Uh, I'm still digging through + + align:start position:0% +there. Uh, I'm still digging through + + + align:start position:0% +there. Uh, I'm still digging through +some of my research, but I'm I'm I've + + align:start position:0% +some of my research, but I'm I'm I've + + + align:start position:0% +some of my research, but I'm I'm I've +got a + + align:start position:0% +got a + + + align:start position:0% +got a +I guess my my argument's formulating + + align:start position:0% +I guess my my argument's formulating + + + align:start position:0% +I guess my my argument's formulating +fairly well in my head and I'm pretty + + align:start position:0% +fairly well in my head and I'm pretty + + + align:start position:0% +fairly well in my head and I'm pretty +comfortable with where I am. Uh like I + + align:start position:0% +comfortable with where I am. Uh like I + + + align:start position:0% +comfortable with where I am. Uh like I +said, the one thing that I'm still just + + align:start position:0% +said, the one thing that I'm still just + + + align:start position:0% +said, the one thing that I'm still just +a bit uncertain of is uh I'm I'm working + + align:start position:0% +a bit uncertain of is uh I'm I'm working + + + align:start position:0% +a bit uncertain of is uh I'm I'm working +on tying in the argument that I said + + align:start position:0% +on tying in the argument that I said + + + align:start position:0% +on tying in the argument that I said +about uh free will and the belief in + + align:start position:0% +about uh free will and the belief in + + + align:start position:0% +about uh free will and the belief in +such thing uh changing the outcome to uh + + align:start position:0% +such thing uh changing the outcome to uh + + + align:start position:0% +such thing uh changing the outcome to uh +the same sort of argument about + + align:start position:0% +the same sort of argument about + + + align:start position:0% +the same sort of argument about +creativity where uh the belief in a a + + align:start position:0% +creativity where uh the belief in a a + + + align:start position:0% +creativity where uh the belief in a a +capacity for original creativity uh + + align:start position:0% +capacity for original creativity uh + + + align:start position:0% +capacity for original creativity uh +actually changes the outcome in a + + align:start position:0% +actually changes the outcome in a + + + align:start position:0% +actually changes the outcome in a +deterministic system. Uh and that's the + + align:start position:0% +deterministic system. Uh and that's the + + + align:start position:0% +deterministic system. Uh and that's the +last little bit I'm kind of working + + align:start position:0% +last little bit I'm kind of working + + + align:start position:0% +last little bit I'm kind of working +through there. + + align:start position:0% +through there. + + + align:start position:0% +through there. +Um, what's the outside research? Uh, + + align:start position:0% +Um, what's the outside research? Uh, + + + align:start position:0% +Um, what's the outside research? Uh, +I've got a number of, uh, + + align:start position:0% +I've got a number of, uh, + + + align:start position:0% +I've got a number of, uh, +things I pull together here. Um, one of + + align:start position:0% +things I pull together here. Um, one of + + + align:start position:0% +things I pull together here. Um, one of +them is, + + align:start position:0% +them is, + + + align:start position:0% +them is, +uh, free will as creativity. It's from + + align:start position:0% +uh, free will as creativity. It's from + + + align:start position:0% +uh, free will as creativity. It's from +this, uh, online, uh, philosophy + + align:start position:0% +this, uh, online, uh, philosophy + + + align:start position:0% +this, uh, online, uh, philosophy +journal. It's saying, oh, it's about + + align:start position:0% +journal. It's saying, oh, it's about + + + align:start position:0% +journal. It's saying, oh, it's about +creativity. I see. Uh, this one's more + + align:start position:0% +creativity. I see. Uh, this one's more + + + align:start position:0% +creativity. I see. Uh, this one's more +about free will and the terminal. I + + align:start position:0% +about free will and the terminal. I + + + align:start position:0% +about free will and the terminal. I +mean, I did all these. The way I found + + align:start position:0% +mean, I did all these. The way I found + + + align:start position:0% +mean, I did all these. The way I found +them was by searching for the real + + align:start position:0% +them was by searching for the real + + + align:start position:0% +them was by searching for the real +creativity. So these all have something + + align:start position:0% +creativity. So these all have something + + + align:start position:0% +creativity. So these all have something +to do with um creativity. Okay. Um you + + align:start position:0% +to do with um creativity. Okay. Um you + + + align:start position:0% +to do with um creativity. Okay. Um you +remember that I gave you two pages of + + align:start position:0% +remember that I gave you two pages of + + + align:start position:0% +remember that I gave you two pages of +uh research material outside partial + + align:start position:0% +uh research material outside partial + + + align:start position:0% +uh research material outside partial +lists. I said um I mean that could be of + + align:start position:0% +lists. I said um I mean that could be of + + + align:start position:0% +lists. I said um I mean that could be of +help depending on what you want to do in + + align:start position:0% +help depending on what you want to do in + + + align:start position:0% +help depending on what you want to do in +your paper. Um do you you feel + + align:start position:0% +your paper. Um do you you feel + + + align:start position:0% +your paper. Um do you you feel +comfortable about it? Yeah. Okay. You + + align:start position:0% +comfortable about it? Yeah. Okay. You + + + align:start position:0% +comfortable about it? Yeah. Okay. You +you Beckard, you are too. You know what + + align:start position:0% +you Beckard, you are too. You know what + + + align:start position:0% +you Beckard, you are too. You know what +you're doing. Um Tom. All right. I'm uh + + align:start position:0% +you're doing. Um Tom. All right. I'm uh + + + align:start position:0% +you're doing. Um Tom. All right. I'm uh +mostly looking at um creative artificial + + align:start position:0% +mostly looking at um creative artificial + + + align:start position:0% +mostly looking at um creative artificial +intelligence. So uh I've got a couple + + align:start position:0% +intelligence. So uh I've got a couple + + + align:start position:0% +intelligence. So uh I've got a couple +examples of uh I'm trying to figure out + + align:start position:0% +examples of uh I'm trying to figure out + + + align:start position:0% +examples of uh I'm trying to figure out +like what has to be done to create + + align:start position:0% +like what has to be done to create + + + align:start position:0% +like what has to be done to create +artificial intelligence that is + + align:start position:0% +artificial intelligence that is + + + align:start position:0% +artificial intelligence that is +creative. What about the Minsk's book? + + align:start position:0% +creative. What about the Minsk's book? + + + align:start position:0% +creative. What about the Minsk's book? +Uh the emotion machine. Pardon? I mean + + align:start position:0% +Uh the emotion machine. Pardon? I mean + + + align:start position:0% +Uh the emotion machine. Pardon? I mean +have you been using that? Uh I've read + + align:start position:0% +have you been using that? Uh I've read + + + align:start position:0% +have you been using that? Uh I've read +it. I don't know. Uh you have read it + + align:start position:0% +it. I don't know. Uh you have read it + + + align:start position:0% +it. I don't know. Uh you have read it +all. Gone through it all. I've read most + + align:start position:0% +all. Gone through it all. I've read most + + + align:start position:0% +all. Gone through it all. I've read most +of it like the first part of it. Um I + + align:start position:0% +of it like the first part of it. Um I + + + align:start position:0% +of it like the first part of it. Um I +I'm not sure how much of it really + + align:start position:0% +I'm not sure how much of it really + + + align:start position:0% +I'm not sure how much of it really +applies to this. I thought uh something + + align:start position:0% +applies to this. I thought uh something + + + align:start position:0% +applies to this. I thought uh something +that was more applicable was uh a paper + + align:start position:0% +that was more applicable was uh a paper + + + align:start position:0% +that was more applicable was uh a paper +by uh Margaret Bone which was uh talking + + align:start position:0% +by uh Margaret Bone which was uh talking + + + align:start position:0% +by uh Margaret Bone which was uh talking +about like conceptual spaces and how + + align:start position:0% +about like conceptual spaces and how + + + align:start position:0% +about like conceptual spaces and how +like uh how that would affect it. I + + align:start position:0% +like uh how that would affect it. I + + + align:start position:0% +like uh how that would affect it. I +think uh like the stuff that Minsky did + + align:start position:0% +think uh like the stuff that Minsky did + + + align:start position:0% +think uh like the stuff that Minsky did +on like uh neural networks and like + + align:start position:0% +on like uh neural networks and like + + + align:start position:0% +on like uh neural networks and like +randomly wired neural networks is pretty + + align:start position:0% +randomly wired neural networks is pretty + + + align:start position:0% +randomly wired neural networks is pretty +uh pretty important to it in terms of + + align:start position:0% +uh pretty important to it in terms of + + + align:start position:0% +uh pretty important to it in terms of +finding like um computers that can like + + align:start position:0% +finding like um computers that can like + + + align:start position:0% +finding like um computers that can like +that's the paper you mentioned last + + align:start position:0% +that's the paper you mentioned last + + + align:start position:0% +that's the paper you mentioned last +week, right? That's true. Okay. And then + + align:start position:0% +week, right? That's true. Okay. And then + + + align:start position:0% +week, right? That's true. Okay. And then +uh I also wanted to look at like um + + align:start position:0% +uh I also wanted to look at like um + + + align:start position:0% +uh I also wanted to look at like um +uh the program Aaron which was uh + + align:start position:0% +uh the program Aaron which was uh + + + align:start position:0% +uh the program Aaron which was uh +written by Harold Cohen and it's like a + + align:start position:0% +written by Harold Cohen and it's like a + + + align:start position:0% +written by Harold Cohen and it's like a +uh like an art making uh program that uh + + align:start position:0% +uh like an art making uh program that uh + + + align:start position:0% +uh like an art making uh program that uh +it's like I guess like uh written in + + align:start position:0% +it's like I guess like uh written in + + + align:start position:0% +it's like I guess like uh written in +lisp and uh it's been it's been given + + align:start position:0% +lisp and uh it's been it's been given + + + align:start position:0% +lisp and uh it's been it's been given +like a lot of uh public attention for + + align:start position:0% +like a lot of uh public attention for + + + align:start position:0% +like a lot of uh public attention for +being like this like creative um like uh + + align:start position:0% +being like this like creative um like uh + + + align:start position:0% +being like this like creative um like uh +like artificial artificial intelligence. + + align:start position:0% +like artificial artificial intelligence. + + + align:start position:0% +like artificial artificial intelligence. +But uh my argument is that it's not in + + align:start position:0% +But uh my argument is that it's not in + + + align:start position:0% +But uh my argument is that it's not in +fact creative because um what it does is + + align:start position:0% +fact creative because um what it does is + + + align:start position:0% +fact creative because um what it does is +it kind of mimics like uh the art style + + align:start position:0% +it kind of mimics like uh the art style + + + align:start position:0% +it kind of mimics like uh the art style +of Harold Cohen. So in the in like in as + + align:start position:0% +of Harold Cohen. So in the in like in as + + + align:start position:0% +of Harold Cohen. So in the in like in as +much as Harold Con's like his art style + + align:start position:0% +much as Harold Con's like his art style + + + align:start position:0% +much as Harold Con's like his art style +would be creative then I guess it would + + align:start position:0% +would be creative then I guess it would + + + align:start position:0% +would be creative then I guess it would +be but like all it can really do is uh + + align:start position:0% +be but like all it can really do is uh + + + align:start position:0% +be but like all it can really do is uh +that one style like there's nothing that + + align:start position:0% +that one style like there's nothing that + + + align:start position:0% +that one style like there's nothing that +it can like it can't like start like a + + align:start position:0% +it can like it can't like start like a + + + align:start position:0% +it can like it can't like start like a +new style or like change like I guess + + align:start position:0% +new style or like change like I guess + + + align:start position:0% +new style or like change like I guess +the conceptual like boundaries that is + + align:start position:0% +the conceptual like boundaries that is + + + align:start position:0% +the conceptual like boundaries that is +what is necessary for like actual + + align:start position:0% +what is necessary for like actual + + + align:start position:0% +what is necessary for like actual +creative act. Um + + align:start position:0% +creative act. Um + + + align:start position:0% +creative act. Um +the + + align:start position:0% +the + + + align:start position:0% +the +in the def in the book on creativ the + + align:start position:0% +in the def in the book on creativ the + + + align:start position:0% +in the def in the book on creativ the +definition of creativity I think is that + + align:start position:0% +definition of creativity I think is that + + + align:start position:0% +definition of creativity I think is that +the name of the anthology that that + + align:start position:0% +the name of the anthology that that + + + align:start position:0% +the name of the anthology that that +Bowden edited and there's an article of + + align:start position:0% +Bowden edited and there's an article of + + + align:start position:0% +Bowden edited and there's an article of +hers in that + + align:start position:0% +hers in that + + + align:start position:0% +hers in that +uh in which she distinguishes between + + align:start position:0% +uh in which she distinguishes between + + + align:start position:0% +uh in which she distinguishes between +the sort of minor and the major kind of + + align:start position:0% +the sort of minor and the major kind of + + + align:start position:0% +the sort of minor and the major kind of +creativity. That's the same idea. She + + align:start position:0% +creativity. That's the same idea. She + + + align:start position:0% +creativity. That's the same idea. She +develops it further or have you not + + align:start position:0% +develops it further or have you not + + + align:start position:0% +develops it further or have you not +looked at that other essay? Um, what's + + align:start position:0% +looked at that other essay? Um, what's + + + align:start position:0% +looked at that other essay? Um, what's +the name of that essay? Uh, the + + align:start position:0% +the name of that essay? Uh, the + + + align:start position:0% +the name of that essay? Uh, the +definition of creativity. Definition of + + align:start position:0% +definition of creativity. Definition of + + + align:start position:0% +definition of creativity. Definition of +creativity. I'll read that, I guess. Um, + + align:start position:0% +creativity. I'll read that, I guess. Um, + + + align:start position:0% +creativity. I'll read that, I guess. Um, +it's conceivable that I have the library + + align:start position:0% +it's conceivable that I have the library + + + align:start position:0% +it's conceivable that I have the library +copy, + + align:start position:0% +copy, + + + align:start position:0% +copy, +but um, yeah, somebody has most of + + align:start position:0% +but um, yeah, somebody has most of + + + align:start position:0% +but um, yeah, somebody has most of +Bowden's books out of the library. I + + align:start position:0% +Bowden's books out of the library. I + + + align:start position:0% +Bowden's books out of the library. I +looked and all the ones dealing with + + align:start position:0% +looked and all the ones dealing with + + + align:start position:0% +looked and all the ones dealing with +creativity are not there. Well, there's + + align:start position:0% +creativity are not there. Well, there's + + + align:start position:0% +creativity are not there. Well, there's +only one of hers that I have and that's + + align:start position:0% +only one of hers that I have and that's + + + align:start position:0% +only one of hers that I have and that's +the book that she edited. + + align:start position:0% +the book that she edited. + + + align:start position:0% +the book that she edited. +But uh possibly you don't need that + + align:start position:0% +But uh possibly you don't need that + + + align:start position:0% +But uh possibly you don't need that +essay of hers because it's all in that + + align:start position:0% +essay of hers because it's all in that + + + align:start position:0% +essay of hers because it's all in that +book that you of hers that you do have. + + align:start position:0% +book that you of hers that you do have. + + + align:start position:0% +book that you of hers that you do have. +Right. Um in terms of your concern, + + align:start position:0% +Right. Um in terms of your concern, + + + align:start position:0% +Right. Um in terms of your concern, +Megan, maybe you ought to try to + + align:start position:0% +Megan, maybe you ought to try to + + + align:start position:0% +Megan, maybe you ought to try to +cooperate with Tom, see what he has out. + + align:start position:0% +cooperate with Tom, see what he has out. + + + align:start position:0% +cooperate with Tom, see what he has out. +Well, I was able to find plenty. I You + + align:start position:0% +Well, I was able to find plenty. I You + + + align:start position:0% +Well, I was able to find plenty. I You +don't need it. Was specifically looking + + align:start position:0% +don't need it. Was specifically looking + + + align:start position:0% +don't need it. Was specifically looking +for those out. Okay. In general, keep in + + align:start position:0% +for those out. Okay. In general, keep in + + + align:start position:0% +for those out. Okay. In general, keep in +mind what you're learning right now + + align:start position:0% +mind what you're learning right now + + + align:start position:0% +mind what you're learning right now +about who has which books out so that + + align:start position:0% +about who has which books out so that + + + align:start position:0% +about who has which books out so that +you can talk to each other and share + + align:start position:0% +you can talk to each other and share + + + align:start position:0% +you can talk to each other and share +them. The one I'm uh like the article I + + align:start position:0% +them. The one I'm uh like the article I + + + align:start position:0% +them. The one I'm uh like the article I +was using was a constructions of the + + align:start position:0% +was using was a constructions of the + + + align:start position:0% +was using was a constructions of the +mind by her. Yeah, I don't know anything + + align:start position:0% +mind by her. Yeah, I don't know anything + + + align:start position:0% +mind by her. Yeah, I don't know anything +about that. + + align:start position:0% +about that. + + + align:start position:0% +about that. +Okay. there um is um somebody whom I + + align:start position:0% +Okay. there um is um somebody whom I + + + align:start position:0% +Okay. there um is um somebody whom I +learned about this weekend who is a + + align:start position:0% +learned about this weekend who is a + + + align:start position:0% +learned about this weekend who is a +professor at Georgia Institute of + + align:start position:0% +professor at Georgia Institute of + + + align:start position:0% +professor at Georgia Institute of +Technology + + align:start position:0% +Technology + + + align:start position:0% +Technology +and uh she has an NE grant this year and + + align:start position:0% +and uh she has an NE grant this year and + + + align:start position:0% +and uh she has an NE grant this year and +is spending her time in Rat at the + + align:start position:0% +is spending her time in Rat at the + + + align:start position:0% +is spending her time in Rat at the +Ratcliffe Institute and the topic of her + + align:start position:0% +Ratcliffe Institute and the topic of her + + + align:start position:0% +Ratcliffe Institute and the topic of her +project is creativity and science. + + align:start position:0% +project is creativity and science. + + + align:start position:0% +project is creativity and science. +um her you might want to I don't know if + + align:start position:0% +um her you might want to I don't know if + + + align:start position:0% +um her you might want to I don't know if +there's time for you to even think of + + align:start position:0% +there's time for you to even think of + + + align:start position:0% +there's time for you to even think of +getting in touch with her if she's right + + align:start position:0% +getting in touch with her if she's right + + + align:start position:0% +getting in touch with her if she's right +in her office or anything but um her + + align:start position:0% +in her office or anything but um her + + + align:start position:0% +in her office or anything but um her +name is um Nancy Nuressian. + + align:start position:0% +name is um Nancy Nuressian. + + + align:start position:0% +name is um Nancy Nuressian. +Well, no actually + + align:start position:0% +Well, no actually + + + align:start position:0% +Well, no actually +look why don't you proceed this way? Um + + align:start position:0% +look why don't you proceed this way? Um + + + align:start position:0% +look why don't you proceed this way? Um +get on to Google and track down Nancy + + align:start position:0% +get on to Google and track down Nancy + + + align:start position:0% +get on to Google and track down Nancy +Nessian. Uh Mikuel is very good about + + align:start position:0% +Nessian. Uh Mikuel is very good about + + + align:start position:0% +Nessian. Uh Mikuel is very good about +doing that on the spot and uh see if + + align:start position:0% +doing that on the spot and uh see if + + + align:start position:0% +doing that on the spot and uh see if +there are any any um extracts from her + + align:start position:0% +there are any any um extracts from her + + + align:start position:0% +there are any any um extracts from her +writings about creativity and science on + + align:start position:0% +writings about creativity and science on + + + align:start position:0% +writings about creativity and science on +the on the internet. You got her + + align:start position:0% +the on the internet. You got her + + + align:start position:0% +the on the internet. You got her +already. Well, it says her research + + align:start position:0% +already. Well, it says her research + + + align:start position:0% +already. Well, it says her research +focuses on human creativity and science. + + align:start position:0% +focuses on human creativity and science. + + + align:start position:0% +focuses on human creativity and science. +The major theme of this research is + + align:start position:0% +The major theme of this research is + + + align:start position:0% +The major theme of this research is +conceptual and innovation and change in + + align:start position:0% +conceptual and innovation and change in + + + align:start position:0% +conceptual and innovation and change in +physics and and physics education. + + align:start position:0% +physics and and physics education. + + + align:start position:0% +physics and and physics education. +specifically the role of analogical and + + align:start position:0% +specifically the role of analogical and + + + align:start position:0% +specifically the role of analogical and +visual modeling and thought + + align:start position:0% +visual modeling and thought + + + align:start position:0% +visual modeling and thought +experimenting simulative modeling. Her + + align:start position:0% +experimenting simulative modeling. Her + + + align:start position:0% +experimenting simulative modeling. Her +current research include investigative + + align:start position:0% +current research include investigative + + + align:start position:0% +current research include investigative +reasoning and representational + + align:start position:0% +reasoning and representational + + + align:start position:0% +reasoning and representational +procedures in interdisciplinary research + + align:start position:0% +procedures in interdisciplinary research + + + align:start position:0% +procedures in interdisciplinary research +laboratories and blah blah blah blah. + + align:start position:0% +laboratories and blah blah blah blah. + + + align:start position:0% +laboratories and blah blah blah blah. +Does that interest any of you? + + align:start position:0% +Does that interest any of you? + + + align:start position:0% +Does that interest any of you? +Okay, then don't worry about it. Uh you + + align:start position:0% +Okay, then don't worry about it. Uh you + + + align:start position:0% +Okay, then don't worry about it. Uh you +have plenty of sources with Bowden's + + align:start position:0% +have plenty of sources with Bowden's + + + align:start position:0% +have plenty of sources with Bowden's +writings. So yeah. Um one other thing + + align:start position:0% +writings. So yeah. Um one other thing + + + align:start position:0% +writings. So yeah. Um one other thing +that was interesting uh interesting to + + align:start position:0% +that was interesting uh interesting to + + + align:start position:0% +that was interesting uh interesting to +me was uh I was looking up like uh like + + align:start position:0% +me was uh I was looking up like uh like + + + align:start position:0% +me was uh I was looking up like uh like +alternate means of like creating uh like + + align:start position:0% +alternate means of like creating uh like + + + align:start position:0% +alternate means of like creating uh like +creative artificial intelligence and I + + align:start position:0% +creative artificial intelligence and I + + + align:start position:0% +creative artificial intelligence and I +came across like the uh the touring uh + + align:start position:0% +came across like the uh the touring uh + + + align:start position:0% +came across like the uh the touring uh +touring test which I guess is + + align:start position:0% +touring test which I guess is + + + align:start position:0% +touring test which I guess is +pardon which I guess is like a way of uh + + align:start position:0% +pardon which I guess is like a way of uh + + + align:start position:0% +pardon which I guess is like a way of uh +trying to make uh artificial + + align:start position:0% +trying to make uh artificial + + + align:start position:0% +trying to make uh artificial +intelligence that could communicate like + + align:start position:0% +intelligence that could communicate like + + + align:start position:0% +intelligence that could communicate like +with a human and the human wouldn't be + + align:start position:0% +with a human and the human wouldn't be + + + align:start position:0% +with a human and the human wouldn't be +able to tell the difference. So, uh, + + align:start position:0% +able to tell the difference. So, uh, + + + align:start position:0% +able to tell the difference. So, uh, +this is just a a label, isn't it? Alan + + align:start position:0% +this is just a a label, isn't it? Alan + + + align:start position:0% +this is just a a label, isn't it? Alan +Turing didn't come up with this, did he? + + align:start position:0% +Turing didn't come up with this, did he? + + + align:start position:0% +Turing didn't come up with this, did he? +He was one of the great, uh, founding + + align:start position:0% +He was one of the great, uh, founding + + + align:start position:0% +He was one of the great, uh, founding +fathers of of artificial intelligence + + align:start position:0% +fathers of of artificial intelligence + + + align:start position:0% +fathers of of artificial intelligence +and apparently a a very very brilliant + + align:start position:0% +and apparently a a very very brilliant + + + align:start position:0% +and apparently a a very very brilliant +and tragic figure in the 1940s. + + align:start position:0% +and tragic figure in the 1940s. + + + align:start position:0% +and tragic figure in the 1940s. +But he didn't himself to do with the + + align:start position:0% +But he didn't himself to do with the + + + align:start position:0% +But he didn't himself to do with the +Turing test, did was he? Did he? I + + align:start position:0% +Turing test, did was he? Did he? I + + + align:start position:0% +Turing test, did was he? Did he? I +thought he I thought he did. Oh, he did. + + align:start position:0% +thought he I thought he did. Oh, he did. + + + align:start position:0% +thought he I thought he did. Oh, he did. +I thought I thought I could written + + align:start position:0% +I thought I thought I could written + + + align:start position:0% +I thought I thought I could written +about Oh, he's written about it, but he + + align:start position:0% +about Oh, he's written about it, but he + + + align:start position:0% +about Oh, he's written about it, but he +didn't set up the the um competition. + + align:start position:0% +didn't set up the the um competition. + + + align:start position:0% +didn't set up the the um competition. +Well, I guess it's like a hypothetical + + align:start position:0% +Well, I guess it's like a hypothetical + + + align:start position:0% +Well, I guess it's like a hypothetical +test. I don't think has it I don't Okay. + + align:start position:0% +test. I don't think has it I don't Okay. + + + align:start position:0% +test. I don't think has it I don't Okay. +Yes, it does. It has been. All right. + + align:start position:0% +Yes, it does. It has been. All right. + + + align:start position:0% +Yes, it does. It has been. All right. +How how + + align:start position:0% +How how + + + align:start position:0% +How how +it's about how is it related to + + align:start position:0% +it's about how is it related to + + + align:start position:0% +it's about how is it related to +creativity? Well, uh like there one of + + align:start position:0% +creativity? Well, uh like there one of + + + align:start position:0% +creativity? Well, uh like there one of +the uh uh one of the ideas for like a + + align:start position:0% +the uh uh one of the ideas for like a + + + align:start position:0% +the uh uh one of the ideas for like a +computer that could be put into it was + + align:start position:0% +computer that could be put into it was + + + align:start position:0% +computer that could be put into it was +uh this one by uh Ned Block, I think. + + align:start position:0% +uh this one by uh Ned Block, I think. + + + align:start position:0% +uh this one by uh Ned Block, I think. +And uh it's like the uh the block head + + align:start position:0% +And uh it's like the uh the block head + + + align:start position:0% +And uh it's like the uh the block head +computer which is a hypothetical + + align:start position:0% +computer which is a hypothetical + + + align:start position:0% +computer which is a hypothetical +computer which would have like uh all + + align:start position:0% +computer which would have like uh all + + + align:start position:0% +computer which would have like uh all +the possible like opening like + + align:start position:0% +the possible like opening like + + + align:start position:0% +the possible like opening like +statements or like beginning uh ways of + + align:start position:0% +statements or like beginning uh ways of + + + align:start position:0% +statements or like beginning uh ways of +like starting the conversation and then + + align:start position:0% +like starting the conversation and then + + + align:start position:0% +like starting the conversation and then +would also have programmed in it like + + align:start position:0% +would also have programmed in it like + + + align:start position:0% +would also have programmed in it like +every uh like correct grammatical + + align:start position:0% +every uh like correct grammatical + + + align:start position:0% +every uh like correct grammatical +response to that um to to any statement + + align:start position:0% +response to that um to to any statement + + + align:start position:0% +response to that um to to any statement +that like the person would get back to + + align:start position:0% +that like the person would get back to + + + align:start position:0% +that like the person would get back to +it. So then uh the idea would be like if + + align:start position:0% +it. So then uh the idea would be like if + + + align:start position:0% +it. So then uh the idea would be like if +it had all of those programmed into it, + + align:start position:0% +it had all of those programmed into it, + + + align:start position:0% +it had all of those programmed into it, +it could have like a uh like a + + align:start position:0% +it could have like a uh like a + + + align:start position:0% +it could have like a uh like a +contextually and a grammatically correct + + align:start position:0% +contextually and a grammatically correct + + + align:start position:0% +contextually and a grammatically correct +response to anything that you might say + + align:start position:0% +response to anything that you might say + + + align:start position:0% +response to anything that you might say +to it. So it would be just like it was a + + align:start position:0% +to it. So it would be just like it was a + + + align:start position:0% +to it. So it would be just like it was a +person like in every way. So is is it is + + align:start position:0% +person like in every way. So is is it is + + + align:start position:0% +person like in every way. So is is it is +basically like Eliza with a very large + + align:start position:0% +basically like Eliza with a very large + + + align:start position:0% +basically like Eliza with a very large +database, right? with like an infinitely + + align:start position:0% +database, right? with like an infinitely + + + align:start position:0% +database, right? with like an infinitely +large database or something because I + + align:start position:0% +large database or something because I + + + align:start position:0% +large database or something because I +guess there's like there are there's + + align:start position:0% +guess there's like there are there's + + + align:start position:0% +guess there's like there are there's +like a uh + + align:start position:0% +like a uh + + + align:start position:0% +like a uh +uh there's like a limited number of + + align:start position:0% +uh there's like a limited number of + + + align:start position:0% +uh there's like a limited number of +possible like uh statements that you + + align:start position:0% +possible like uh statements that you + + + align:start position:0% +possible like uh statements that you +could say. So I I was talking I was kind + + align:start position:0% +could say. So I I was talking I was kind + + + align:start position:0% +could say. So I I was talking I was kind +of thinking about like whether or not + + align:start position:0% +of thinking about like whether or not + + + align:start position:0% +of thinking about like whether or not +that would be something that would be + + align:start position:0% +that would be something that would be + + + align:start position:0% +that would be something that would be +creative then because it would act + + align:start position:0% +creative then because it would act + + + align:start position:0% +creative then because it would act +exactly like a person would in the + + align:start position:0% +exactly like a person would in the + + + align:start position:0% +exactly like a person would in the +situation or whether or not that would + + align:start position:0% +situation or whether or not that would + + + align:start position:0% +situation or whether or not that would +just be like just the sum of its + + align:start position:0% +just be like just the sum of its + + + align:start position:0% +just be like just the sum of its +components. Anybody + + align:start position:0% + + + + align:start position:0% + +want to say anything about this? + + align:start position:0% +want to say anything about this? + + + align:start position:0% +want to say anything about this? +Well, keep working. You seem to know + + align:start position:0% +Well, keep working. You seem to know + + + align:start position:0% +Well, keep working. You seem to know +what you're doing really well. Is there + + align:start position:0% +what you're doing really well. Is there + + + align:start position:0% +what you're doing really well. Is there +any way you can think that I can be + + align:start position:0% +any way you can think that I can be + + + align:start position:0% +any way you can think that I can be +helpful? + + align:start position:0% +helpful? + + + align:start position:0% +helpful? +Um, I think I'm Is this a good moment to + + align:start position:0% +Um, I think I'm Is this a good moment to + + + align:start position:0% +Um, I think I'm Is this a good moment to +come back to a discussion of um of um + + align:start position:0% +come back to a discussion of um of um + + + align:start position:0% +come back to a discussion of um of um +the emotion machine of Minsky's? + + align:start position:0% +the emotion machine of Minsky's? + + + align:start position:0% +the emotion machine of Minsky's? +Let me let me take over for just a few + + align:start position:0% +Let me let me take over for just a few + + + align:start position:0% +Let me let me take over for just a few +minutes. But I mean, it turns out that I + + align:start position:0% +minutes. But I mean, it turns out that I + + + align:start position:0% +minutes. But I mean, it turns out that I +can stay until 5 instead of returning to + + align:start position:0% +can stay until 5 instead of returning to + + + align:start position:0% +can stay until 5 instead of returning to +my + + align:start position:0% +my + + + align:start position:0% +my +emergency. + + align:start position:0% + + + + align:start position:0% + +uh but and I do but there and there + + align:start position:0% +uh but and I do but there and there + + + align:start position:0% +uh but and I do but there and there +should be enough time for everybody. Um + + align:start position:0% +should be enough time for everybody. Um + + + align:start position:0% +should be enough time for everybody. Um +I wrote down a number of questions + + align:start position:0% +I wrote down a number of questions + + + align:start position:0% +I wrote down a number of questions +relevant to the emotion machine that + + align:start position:0% +relevant to the emotion machine that + + + align:start position:0% +relevant to the emotion machine that +might interest you. + + align:start position:0% +might interest you. + + + align:start position:0% +might interest you. +The first is um what is it that um + + align:start position:0% +The first is um what is it that um + + + align:start position:0% +The first is um what is it that um +Minsky is trying to do at all? And the + + align:start position:0% +Minsky is trying to do at all? And the + + + align:start position:0% +Minsky is trying to do at all? And the +one would be how to construct a humanoid + + align:start position:0% +one would be how to construct a humanoid + + + align:start position:0% +one would be how to construct a humanoid +machine naturally. I mean everybody with + + align:start position:0% +machine naturally. I mean everybody with + + + align:start position:0% +machine naturally. I mean everybody with +in artificial intelligence has that in + + align:start position:0% +in artificial intelligence has that in + + + align:start position:0% +in artificial intelligence has that in +mind. But second is how to make uh + + align:start position:0% +mind. But second is how to make uh + + + align:start position:0% +mind. But second is how to make uh +computers that are sensitive to human + + align:start position:0% +computers that are sensitive to human + + + align:start position:0% +computers that are sensitive to human +feelings. And that's where the work of + + align:start position:0% +feelings. And that's where the work of + + + align:start position:0% +feelings. And that's where the work of +Rosalind Picard comes in. She's here uh + + align:start position:0% +Rosalind Picard comes in. She's here uh + + + align:start position:0% +Rosalind Picard comes in. She's here uh +at the um media lab and there's a book + + align:start position:0% +at the um media lab and there's a book + + + align:start position:0% +at the um media lab and there's a book +of hers um affective computing that + + align:start position:0% +of hers um affective computing that + + + align:start position:0% +of hers um affective computing that +deals directly with that. So that you + + align:start position:0% +deals directly with that. So that you + + + align:start position:0% +deals directly with that. So that you +might want to look at that. Uh but third + + align:start position:0% +might want to look at that. Uh but third + + + align:start position:0% +might want to look at that. Uh but third +what interests me most and which I think + + align:start position:0% +what interests me most and which I think + + + align:start position:0% +what interests me most and which I think +Minsky is also interested in is what are + + align:start position:0% +Minsky is also interested in is what are + + + align:start position:0% +Minsky is also interested in is what are +the relationship + + align:start position:0% +the relationship + + + align:start position:0% +the relationship +uh between mind and matter meaning by + + align:start position:0% +uh between mind and matter meaning by + + + align:start position:0% +uh between mind and matter meaning by +mind feeling including feelings in what + + align:start position:0% +mind feeling including feelings in what + + + align:start position:0% +mind feeling including feelings in what +we mean by mind. what is the interaction + + align:start position:0% +we mean by mind. what is the interaction + + + align:start position:0% +we mean by mind. what is the interaction +between um the two of them and out of + + align:start position:0% +between um the two of them and out of + + + align:start position:0% +between um the two of them and out of +that uh how can affective and and + + align:start position:0% +that uh how can affective and and + + + align:start position:0% +that uh how can affective and and +cognitive approaches + + align:start position:0% +cognitive approaches + + + align:start position:0% +cognitive approaches +uh be related to each other. Now the um + + align:start position:0% +uh be related to each other. Now the um + + + align:start position:0% +uh be related to each other. Now the um +effort that Minsky makes is very + + align:start position:0% +effort that Minsky makes is very + + + align:start position:0% +effort that Minsky makes is very +interesting to me because he's obvious I + + align:start position:0% +interesting to me because he's obvious I + + + align:start position:0% +interesting to me because he's obvious I +don't know him very well though + + align:start position:0% +don't know him very well though + + + align:start position:0% +don't know him very well though +apparently we over overlapped in various + + align:start position:0% +apparently we over overlapped in various + + + align:start position:0% +apparently we over overlapped in various +ways. Uh but I I can't say that he's a + + align:start position:0% +ways. Uh but I I can't say that he's a + + + align:start position:0% +ways. Uh but I I can't say that he's a +friend of mine or that I've had a really + + align:start position:0% +friend of mine or that I've had a really + + + align:start position:0% +friend of mine or that I've had a really +serious discussion with him. But I find + + align:start position:0% +serious discussion with him. But I find + + + align:start position:0% +serious discussion with him. But I find +uh his writing very impressive once he + + align:start position:0% +uh his writing very impressive once he + + + align:start position:0% +uh his writing very impressive once he +steps back from the official program of + + align:start position:0% +steps back from the official program of + + + align:start position:0% +steps back from the official program of +what he's doing as one of the founders + + align:start position:0% +what he's doing as one of the founders + + + align:start position:0% +what he's doing as one of the founders +of artificial intelligence and talks + + align:start position:0% +of artificial intelligence and talks + + + align:start position:0% +of artificial intelligence and talks +about the world about life about the way + + align:start position:0% +about the world about life about the way + + + align:start position:0% +about the world about life about the way +a moralist would uh the way somebody in + + align:start position:0% +a moralist would uh the way somebody in + + + align:start position:0% +a moralist would uh the way somebody in +literature or humanistic philosophy + + align:start position:0% +literature or humanistic philosophy + + + align:start position:0% +literature or humanistic philosophy +would the way I try to do only he does + + align:start position:0% +would the way I try to do only he does + + + align:start position:0% +would the way I try to do only he does +it better from his own point of view and + + align:start position:0% +it better from his own point of view and + + + align:start position:0% +it better from his own point of view and +totally ignores what I'm doing which I'm + + align:start position:0% +totally ignores what I'm doing which I'm + + + align:start position:0% +totally ignores what I'm doing which I'm +used to but what he does seems to me + + align:start position:0% +used to but what he does seems to me + + + align:start position:0% +used to but what he does seems to me +very attractive and very indicates that + + align:start position:0% +very attractive and very indicates that + + + align:start position:0% +very attractive and very indicates that +he's a brilliant man but I don't see the + + align:start position:0% +he's a brilliant man but I don't see the + + + align:start position:0% +he's a brilliant man but I don't see the +connection with the rest as being + + align:start position:0% +connection with the rest as being + + + align:start position:0% +connection with the rest as being +established in the hope in the way that + + align:start position:0% +established in the hope in the way that + + + align:start position:0% +established in the hope in the way that +he hopes um he he hopes that by talking + + align:start position:0% +he hopes um he he hopes that by talking + + + align:start position:0% +he hopes um he he hopes that by talking +about um the body the brain artificial + + align:start position:0% +about um the body the brain artificial + + + align:start position:0% +about um the body the brain artificial +intelligence on a mechanistic ma basis + + align:start position:0% +intelligence on a mechanistic ma basis + + + align:start position:0% +intelligence on a mechanistic ma basis +will explain all of these other insights + + align:start position:0% +will explain all of these other insights + + + align:start position:0% +will explain all of these other insights +that he has about human nature and about + + align:start position:0% +that he has about human nature and about + + + align:start position:0% +that he has about human nature and about +life and I don't fe find that I find + + align:start position:0% +life and I don't fe find that I find + + + align:start position:0% +life and I don't fe find that I find +these two different compartments uh in + + align:start position:0% +these two different compartments uh in + + + align:start position:0% +these two different compartments uh in +his mind maybe that is enough maybe + + align:start position:0% +his mind maybe that is enough maybe + + + align:start position:0% +his mind maybe that is enough maybe +that's all that anybody can do nowadays + + align:start position:0% +that's all that anybody can do nowadays + + + align:start position:0% +that's all that anybody can do nowadays +but that perception uh is strong me and + + align:start position:0% +but that perception uh is strong me and + + + align:start position:0% +but that perception uh is strong me and +possibly I'm right possibly I'm wrong uh + + align:start position:0% +possibly I'm right possibly I'm wrong uh + + + align:start position:0% +possibly I'm right possibly I'm wrong uh +at the beginning of the first chapter + + align:start position:0% +at the beginning of the first chapter + + + align:start position:0% +at the beginning of the first chapter +um he talks right you know right throws + + align:start position:0% +um he talks right you know right throws + + + align:start position:0% +um he talks right you know right throws +it in your face he talks about the + + align:start position:0% +it in your face he talks about the + + + align:start position:0% +it in your face he talks about the +nature of love uh which doesn't sound + + align:start position:0% +nature of love uh which doesn't sound + + + align:start position:0% +nature of love uh which doesn't sound +very much like artificial intelligence + + align:start position:0% +very much like artificial intelligence + + + align:start position:0% +very much like artificial intelligence +uh and quotes I don't know how many of + + align:start position:0% +uh and quotes I don't know how many of + + + align:start position:0% +uh and quotes I don't know how many of +you noticed this uh from Darthothy + + align:start position:0% +you noticed this uh from Darthothy + + + align:start position:0% +you noticed this uh from Darthothy +Parker who was a very important not + + align:start position:0% +Parker who was a very important not + + + align:start position:0% +Parker who was a very important not +quite a great writer but a very + + align:start position:0% +quite a great writer but a very + + + align:start position:0% +quite a great writer but a very +outstanding writer of the 1920s and 30s + + align:start position:0% +outstanding writer of the 1920s and 30s + + + align:start position:0% +outstanding writer of the 1920s and 30s +who published in poems in the New Yorker + + align:start position:0% +who published in poems in the New Yorker + + + align:start position:0% +who published in poems in the New Yorker +um and was extremely witty but uh in a + + align:start position:0% +um and was extremely witty but uh in a + + + align:start position:0% +um and was extremely witty but uh in a +kind of disillusioned embittered sort of + + align:start position:0% +kind of disillusioned embittered sort of + + + align:start position:0% +kind of disillusioned embittered sort of +way. Uh I don't know whether any of you + + align:start position:0% +way. Uh I don't know whether any of you + + + align:start position:0% +way. Uh I don't know whether any of you +have read anything by her but the poem + + align:start position:0% +have read anything by her but the poem + + + align:start position:0% +have read anything by her but the poem +that Minsky starts with uh is + + align:start position:0% +that Minsky starts with uh is + + + align:start position:0% +that Minsky starts with uh is +characteristic of her. He gives only the + + align:start position:0% +characteristic of her. He gives only the + + + align:start position:0% +characteristic of her. He gives only the +first four lines or or maybe I can't + + align:start position:0% +first four lines or or maybe I can't + + + align:start position:0% +first four lines or or maybe I can't +remember now maybe this is the whole + + align:start position:0% +remember now maybe this is the whole + + + align:start position:0% +remember now maybe this is the whole +poem and let me read it to you. Oh, life + + align:start position:0% +poem and let me read it to you. Oh, life + + + align:start position:0% +poem and let me read it to you. Oh, life +is a glorious + + align:start position:0% +is a glorious + + + align:start position:0% +is a glorious +cycle of song, a medley of + + align:start position:0% +cycle of song, a medley of + + + align:start position:0% +cycle of song, a medley of +extemporaneia, + + align:start position:0% +extemporaneia, + + + align:start position:0% +extemporaneia, +and love is a thing that can never go + + align:start position:0% +and love is a thing that can never go + + + align:start position:0% +and love is a thing that can never go +wrong. And I am Marie of Romania. Uh, + + align:start position:0% +wrong. And I am Marie of Romania. Uh, + + + align:start position:0% +wrong. And I am Marie of Romania. Uh, +Marie of Marie of Romania was a queen at + + align:start position:0% +Marie of Marie of Romania was a queen at + + + align:start position:0% +Marie of Marie of Romania was a queen at +that point. So the poet is obviously + + align:start position:0% +that point. So the poet is obviously + + + align:start position:0% +that point. So the poet is obviously +insane + + align:start position:0% +insane + + + align:start position:0% +insane +and and that explains this gush of + + align:start position:0% +and and that explains this gush of + + + align:start position:0% +and and that explains this gush of +enthusiasm about love. Um now it's very + + align:start position:0% +enthusiasm about love. Um now it's very + + + align:start position:0% +enthusiasm about love. Um now it's very +witty and um um + + align:start position:0% +witty and um um + + + align:start position:0% +witty and um um +um Minsky + + align:start position:0% +um Minsky + + + align:start position:0% +um Minsky +um used to uh I mean um uses it very + + align:start position:0% +um used to uh I mean um uses it very + + + align:start position:0% +um used to uh I mean um uses it very +effectively to make his points about + + align:start position:0% +effectively to make his points about + + + align:start position:0% +effectively to make his points about +love. They boil down to uh his saying + + align:start position:0% +love. They boil down to uh his saying + + + align:start position:0% +love. They boil down to uh his saying +that by studying where is it? Um + + align:start position:0% + + + + align:start position:0% + +I guess it's on another maybe no it's on + + align:start position:0% +I guess it's on another maybe no it's on + + + align:start position:0% +I guess it's on another maybe no it's on +another page in which he says throughout + + align:start position:0% +another page in which he says throughout + + + align:start position:0% +another page in which he says throughout +this book what we're going to do is to + + align:start position:0% +this book what we're going to do is to + + + align:start position:0% +this book what we're going to do is to +show how it is that people given their + + align:start position:0% +show how it is that people given their + + + align:start position:0% +show how it is that people given their +bodily equipment and their brains um + + align:start position:0% +bodily equipment and their brains um + + + align:start position:0% +bodily equipment and their brains um +their hard wiring which would be + + align:start position:0% +their hard wiring which would be + + + align:start position:0% +their hard wiring which would be +relevant to the work of artificial + + align:start position:0% +relevant to the work of artificial + + + align:start position:0% +relevant to the work of artificial +intelligence the making of robots how + + align:start position:0% +intelligence the making of robots how + + + align:start position:0% +intelligence the making of robots how +they're capable even of having + + align:start position:0% +they're capable even of having + + + align:start position:0% +they're capable even of having +experiences of love, whatever love may + + align:start position:0% +experiences of love, whatever love may + + + align:start position:0% +experiences of love, whatever love may +be. And he gives a kind of analysis of + + align:start position:0% +be. And he gives a kind of analysis of + + + align:start position:0% +be. And he gives a kind of analysis of +it, which is not very advanced and you + + align:start position:0% +it, which is not very advanced and you + + + align:start position:0% +it, which is not very advanced and you +know, since I've spent so much of my + + align:start position:0% +know, since I've spent so much of my + + + align:start position:0% +know, since I've spent so much of my +life on this uh sort of amateurish, but + + align:start position:0% +life on this uh sort of amateurish, but + + + align:start position:0% +life on this uh sort of amateurish, but +utterly respectable and I wouldn't + + align:start position:0% +utterly respectable and I wouldn't + + + align:start position:0% +utterly respectable and I wouldn't +demean his um you doing what he's done + + align:start position:0% +demean his um you doing what he's done + + + align:start position:0% +demean his um you doing what he's done +about love. Um but the point is that + + align:start position:0% +about love. Um but the point is that + + + align:start position:0% +about love. Um but the point is that +what I focus on is the fact that we he's + + align:start position:0% +what I focus on is the fact that we he's + + + align:start position:0% +what I focus on is the fact that we he's +offering um a mechanistic analysis of + + align:start position:0% +offering um a mechanistic analysis of + + + align:start position:0% +offering um a mechanistic analysis of +the body as a way of explaining + + align:start position:0% +the body as a way of explaining + + + align:start position:0% +the body as a way of explaining +something that most people have never + + align:start position:0% +something that most people have never + + + align:start position:0% +something that most people have never +thought cannot be explained that is not + + align:start position:0% +thought cannot be explained that is not + + + align:start position:0% +thought cannot be explained that is not +reducible merely to physiological or um + + align:start position:0% +reducible merely to physiological or um + + + align:start position:0% +reducible merely to physiological or um +other bodily um explorations. In other + + align:start position:0% +other bodily um explorations. In other + + + align:start position:0% +other bodily um explorations. In other +words, he he rejects a Freudian + + align:start position:0% +words, he he rejects a Freudian + + + align:start position:0% +words, he he rejects a Freudian +reduction of love to sex or any any + + align:start position:0% +reduction of love to sex or any any + + + align:start position:0% +reduction of love to sex or any any +statement of it in terms of chemistry or + + align:start position:0% +statement of it in terms of chemistry or + + + align:start position:0% +statement of it in terms of chemistry or +or + + align:start position:0% +or + + + align:start position:0% +or +hormones um in order to give his own + + align:start position:0% +hormones um in order to give his own + + + align:start position:0% +hormones um in order to give his own +idea of what he's talking about and that + + align:start position:0% +idea of what he's talking about and that + + + align:start position:0% +idea of what he's talking about and that +uh studying artificial intelligence will + + align:start position:0% +uh studying artificial intelligence will + + + align:start position:0% +uh studying artificial intelligence will +help us to understand what brings it + + align:start position:0% +help us to understand what brings it + + + align:start position:0% +help us to understand what brings it +about. Okay. on in page in the third + + align:start position:0% +about. Okay. on in page in the third + + + align:start position:0% +about. Okay. on in page in the third +chapter. However, + + align:start position:0% +chapter. However, + + + align:start position:0% +chapter. However, +um he then takes another tact which is + + align:start position:0% +um he then takes another tact which is + + + align:start position:0% +um he then takes another tact which is +the one that I was talking about last + + align:start position:0% +the one that I was talking about last + + + align:start position:0% +the one that I was talking about last +time that that I mentioned today uh + + align:start position:0% +time that that I mentioned today uh + + + align:start position:0% +time that that I mentioned today uh +briefly. I will argue that each of our + + align:start position:0% +briefly. I will argue that each of our + + + align:start position:0% +briefly. I will argue that each of our +various each of our various mental + + align:start position:0% +various each of our various mental + + + align:start position:0% +various each of our various mental +states so that would include our + + align:start position:0% +states so that would include our + + + align:start position:0% +states so that would include our +feelings is a different pattern of ways + + align:start position:0% +feelings is a different pattern of ways + + + align:start position:0% +feelings is a different pattern of ways +to think and that what we call feelings + + align:start position:0% +to think and that what we call feelings + + + align:start position:0% +to think and that what we call feelings +could be attempts by some parts of a of + + align:start position:0% +could be attempts by some parts of a of + + + align:start position:0% +could be attempts by some parts of a of +a mind to describe some aspects of those + + align:start position:0% +a mind to describe some aspects of those + + + align:start position:0% +a mind to describe some aspects of those +conditions. Now that's a contradiction I + + align:start position:0% +conditions. Now that's a contradiction I + + + align:start position:0% +conditions. Now that's a contradiction I +think to the first view and the + + align:start position:0% +think to the first view and the + + + align:start position:0% +think to the first view and the +fluctuates back and forth. Uh and that I + + align:start position:0% +fluctuates back and forth. Uh and that I + + + align:start position:0% +fluctuates back and forth. Uh and that I +think is a problem uh with much of what + + align:start position:0% +think is a problem uh with much of what + + + align:start position:0% +think is a problem uh with much of what +he has to say. Um let let's go back now + + align:start position:0% +he has to say. Um let let's go back now + + + align:start position:0% +he has to say. Um let let's go back now +to um uh Tom if he wants or if you've + + align:start position:0% +to um uh Tom if he wants or if you've + + + align:start position:0% +to um uh Tom if he wants or if you've +exhausted your ideas. I mean if if if + + align:start position:0% +exhausted your ideas. I mean if if if + + + align:start position:0% +exhausted your ideas. I mean if if if +you have said as much as about your use + + align:start position:0% +you have said as much as about your use + + + align:start position:0% +you have said as much as about your use +of artificial intelligence as you want + + align:start position:0% +of artificial intelligence as you want + + + align:start position:0% +of artificial intelligence as you want +to we can go further. Do you want it to + + align:start position:0% +to we can go further. Do you want it to + + + align:start position:0% +to we can go further. Do you want it to +go? You don't want you don't feel any + + align:start position:0% +go? You don't want you don't feel any + + + align:start position:0% +go? You don't want you don't feel any +need. Yeah. All right. With all of you + + align:start position:0% +need. Yeah. All right. With all of you + + + align:start position:0% +need. Yeah. All right. With all of you +please read carefully the paragraph at + + align:start position:0% +please read carefully the paragraph at + + + align:start position:0% +please read carefully the paragraph at +the bottom of the syllabus. + + align:start position:0% + + + + align:start position:0% + +Um Amy + + align:start position:0% +Um Amy + + + align:start position:0% +Um Amy +Um I read the from the related resources + + align:start position:0% +Um I read the from the related resources + + + align:start position:0% +Um I read the from the related resources +the nature of creativity by Sternberg. + + align:start position:0% +the nature of creativity by Sternberg. + + + align:start position:0% +the nature of creativity by Sternberg. +It's a collection of essays and I talked + + align:start position:0% +It's a collection of essays and I talked + + + align:start position:0% +It's a collection of essays and I talked +about last week I'm going to talk about + + align:start position:0% +about last week I'm going to talk about + + + align:start position:0% +about last week I'm going to talk about +the investment theory of creativity + + align:start position:0% +the investment theory of creativity + + + align:start position:0% +the investment theory of creativity +which asserts that creative thinkers are + + align:start position:0% +which asserts that creative thinkers are + + + align:start position:0% +which asserts that creative thinkers are +like good investors who buy low and sell + + align:start position:0% +like good investors who buy low and sell + + + align:start position:0% +like good investors who buy low and sell +high and basically want to generate + + align:start position:0% +high and basically want to generate + + + align:start position:0% +high and basically want to generate +ideas. Okay. That's that's what you + + align:start position:0% +ideas. Okay. That's that's what you + + + align:start position:0% +ideas. Okay. That's that's what you +mentioned last time. Have you progressed + + align:start position:0% +mentioned last time. Have you progressed + + + align:start position:0% +mentioned last time. Have you progressed +further? Yeah. So basically what I'm + + align:start position:0% +further? Yeah. So basically what I'm + + + align:start position:0% +further? Yeah. So basically what I'm +going to do is they + + align:start position:0% +going to do is they + + + align:start position:0% +going to do is they +divide up creativity like make an effort + + align:start position:0% +divide up creativity like make an effort + + + align:start position:0% +divide up creativity like make an effort +to define it into different categories. + + align:start position:0% +to define it into different categories. + + + align:start position:0% +to define it into different categories. +Those being um in terms of creative + + align:start position:0% +Those being um in terms of creative + + + align:start position:0% +Those being um in terms of creative +leadership um say more more um they're + + align:start position:0% +leadership um say more more um they're + + + align:start position:0% +leadership um say more more um they're +dividing slowly at the crucial points + + align:start position:0% +dividing slowly at the crucial points + + + align:start position:0% +dividing slowly at the crucial points +they're dividing + + align:start position:0% +they're dividing + + + align:start position:0% +they're dividing +um different types of creativity into + + align:start position:0% +um different types of creativity into + + + align:start position:0% +um different types of creativity into +different categories. Those being Go + + align:start position:0% +different categories. Those being Go + + + align:start position:0% +different categories. Those being Go +ahead. Right. Those being um leadership + + align:start position:0% +ahead. Right. Those being um leadership + + + align:start position:0% +ahead. Right. Those being um leadership +that accepts existing ways of doing + + align:start position:0% +that accepts existing ways of doing + + + align:start position:0% +that accepts existing ways of doing +leadership that accepts existing ways of + + align:start position:0% +leadership that accepts existing ways of + + + align:start position:0% +leadership that accepts existing ways of +doing things + + align:start position:0% +doing things + + + align:start position:0% +doing things +um which could include replication, + + align:start position:0% +um which could include replication, + + + align:start position:0% +um which could include replication, +redefination, + + align:start position:0% + + + + align:start position:0% + +either trying to advance an existing + + align:start position:0% +either trying to advance an existing + + + align:start position:0% +either trying to advance an existing +idea a little bit or trying to advance + + align:start position:0% +idea a little bit or trying to advance + + + align:start position:0% +idea a little bit or trying to advance +an existing idea. That sounds like the + + align:start position:0% +an existing idea. That sounds like the + + + align:start position:0% +an existing idea. That sounds like the +second of Bowden's categories + + align:start position:0% +second of Bowden's categories + + + align:start position:0% +second of Bowden's categories +where um if it's creative it's at a + + align:start position:0% +where um if it's creative it's at a + + + align:start position:0% +where um if it's creative it's at a +lesser level or to a lesser lesser + + align:start position:0% +lesser level or to a lesser lesser + + + align:start position:0% +lesser level or to a lesser lesser +degree. uh in that uh chapter that + + align:start position:0% +degree. uh in that uh chapter that + + + align:start position:0% +degree. uh in that uh chapter that +called the definition of creativity that + + align:start position:0% +called the definition of creativity that + + + align:start position:0% +called the definition of creativity that +I mentioned uh she contrasts Mozart and + + align:start position:0% +I mentioned uh she contrasts Mozart and + + + align:start position:0% +I mentioned uh she contrasts Mozart and +Beetho and Heiden in that respect that + + align:start position:0% +Beetho and Heiden in that respect that + + + align:start position:0% +Beetho and Heiden in that respect that +what Heiden does is creative but within + + align:start position:0% +what Heiden does is creative but within + + + align:start position:0% +what Heiden does is creative but within +limits set by the musical tradition what + + align:start position:0% +limits set by the musical tradition what + + + align:start position:0% +limits set by the musical tradition what +we call classical music which he was one + + align:start position:0% +we call classical music which he was one + + + align:start position:0% +we call classical music which he was one +of the founders of but that he had + + align:start position:0% +of the founders of but that he had + + + align:start position:0% +of the founders of but that he had +somehow to a large extent some degree + + align:start position:0% +somehow to a large extent some degree + + + align:start position:0% +somehow to a large extent some degree +had inherited from the way music was + + align:start position:0% +had inherited from the way music was + + + align:start position:0% +had inherited from the way music was +being done at that time in the early + + align:start position:0% +being done at that time in the early + + + align:start position:0% +being done at that time in the early +18th century. + + align:start position:0% +18th century. + + + align:start position:0% +18th century. +That's to be contrasted with Mozart who + + align:start position:0% +That's to be contrasted with Mozart who + + + align:start position:0% +That's to be contrasted with Mozart who +um digests all of that. But then he does + + align:start position:0% +um digests all of that. But then he does + + + align:start position:0% +um digests all of that. But then he does +these very different + + align:start position:0% +these very different + + + align:start position:0% +these very different +basically extensively different kinds of + + align:start position:0% +basically extensively different kinds of + + + align:start position:0% +basically extensively different kinds of +uses of the accepted rules. + + align:start position:0% +uses of the accepted rules. + + + align:start position:0% +uses of the accepted rules. +Um and as I think I mentioned in the + + align:start position:0% +Um and as I think I mentioned in the + + + align:start position:0% +Um and as I think I mentioned in the +first class of the course, I myself + + align:start position:0% +first class of the course, I myself + + + align:start position:0% +first class of the course, I myself +would then contrast Mozart with + + align:start position:0% +would then contrast Mozart with + + + align:start position:0% +would then contrast Mozart with +Beethoven because Mozart was a great + + align:start position:0% +Beethoven because Mozart was a great + + + align:start position:0% +Beethoven because Mozart was a great +genius who knew how to invent he in a + + align:start position:0% +genius who knew how to invent he in a + + + align:start position:0% +genius who knew how to invent he in a +sense one might even this I don't know + + align:start position:0% +sense one might even this I don't know + + + align:start position:0% +sense one might even this I don't know +if this is uh going to make much sense + + align:start position:0% +if this is uh going to make much sense + + + align:start position:0% +if this is uh going to make much sense +but let's try it out. uh that Mozart was + + align:start position:0% +but let's try it out. uh that Mozart was + + + align:start position:0% +but let's try it out. uh that Mozart was +not creative in his genius so much as + + align:start position:0% +not creative in his genius so much as + + + align:start position:0% +not creative in his genius so much as +inventive. Um that he would invent new + + align:start position:0% +inventive. Um that he would invent new + + + align:start position:0% +inventive. Um that he would invent new +melodies. He would turn on the faucet + + align:start position:0% +melodies. He would turn on the faucet + + + align:start position:0% +melodies. He would turn on the faucet +and out would come all of these + + align:start position:0% +and out would come all of these + + + align:start position:0% +and out would come all of these +different possibilities, but that they + + align:start position:0% +different possibilities, but that they + + + align:start position:0% +different possibilities, but that they +were not based on some fundamental + + align:start position:0% +were not based on some fundamental + + + align:start position:0% +were not based on some fundamental +construction of new rules uh for doing + + align:start position:0% +construction of new rules uh for doing + + + align:start position:0% +construction of new rules uh for doing +music or new forms of music. Whereas + + align:start position:0% +music or new forms of music. Whereas + + + align:start position:0% +music or new forms of music. Whereas +Beethoven + + align:start position:0% +Beethoven + + + align:start position:0% +Beethoven +uh was creative in that respect that uh + + align:start position:0% +uh was creative in that respect that uh + + + align:start position:0% +uh was creative in that respect that uh +he did invent those + + align:start position:0% +he did invent those + + + align:start position:0% +he did invent those +new new ways of doing things. He + + align:start position:0% +new new ways of doing things. He + + + align:start position:0% +new new ways of doing things. He +experimented with them and and when he + + align:start position:0% +experimented with them and and when he + + + align:start position:0% +experimented with them and and when he +did them uh people thought they were + + align:start position:0% +did them uh people thought they were + + + align:start position:0% +did them uh people thought they were +very strange and wild. Um I was reading + + align:start position:0% +very strange and wild. Um I was reading + + + align:start position:0% +very strange and wild. Um I was reading +a biography of Mendlesson uh who was + + align:start position:0% +a biography of Mendlesson uh who was + + + align:start position:0% +a biography of Mendlesson uh who was +himself a genius and whose father um um + + align:start position:0% +himself a genius and whose father um um + + + align:start position:0% +himself a genius and whose father um um +um was uh great lover of music and very + + align:start position:0% +um was uh great lover of music and very + + + align:start position:0% +um was uh great lover of music and very +very knowledgeable. Um and the father uh + + align:start position:0% +very knowledgeable. Um and the father uh + + + align:start position:0% +very knowledgeable. Um and the father uh +didn't think much of Beethoven. This + + align:start position:0% +didn't think much of Beethoven. This + + + align:start position:0% +didn't think much of Beethoven. This +would be in the early 19th century maybe + + align:start position:0% +would be in the early 19th century maybe + + + align:start position:0% +would be in the early 19th century maybe +couple of decades after Beethoven died. + + align:start position:0% +couple of decades after Beethoven died. + + + align:start position:0% +couple of decades after Beethoven died. +And uh he said all this you know the + + align:start position:0% +And uh he said all this you know the + + + align:start position:0% +And uh he said all this you know the +last quartets they're just sort of + + align:start position:0% +last quartets they're just sort of + + + align:start position:0% +last quartets they're just sort of +formless and wild and unprincipled and + + align:start position:0% +formless and wild and unprincipled and + + + align:start position:0% +formless and wild and unprincipled and +he didn't think much of Beethoven. The + + align:start position:0% +he didn't think much of Beethoven. The + + + align:start position:0% +he didn't think much of Beethoven. The +truth is that Beethoven was + + align:start position:0% +truth is that Beethoven was + + + align:start position:0% +truth is that Beethoven was +experimenting with new forms in such an + + align:start position:0% +experimenting with new forms in such an + + + align:start position:0% +experimenting with new forms in such an +original way that many people couldn't + + align:start position:0% +original way that many people couldn't + + + align:start position:0% +original way that many people couldn't +quite even practice uh sympathetic + + align:start position:0% +quite even practice uh sympathetic + + + align:start position:0% +quite even practice uh sympathetic +musicians couldn't understand what he + + align:start position:0% +musicians couldn't understand what he + + + align:start position:0% +musicians couldn't understand what he +was doing. Well that would be a + + align:start position:0% +was doing. Well that would be a + + + align:start position:0% +was doing. Well that would be a +different mode of creativity. So you + + align:start position:0% +different mode of creativity. So you + + + align:start position:0% +different mode of creativity. So you +would have if you want to explore this + + align:start position:0% +would have if you want to explore this + + + align:start position:0% +would have if you want to explore this +let's go back to the Bowden chapter uh + + align:start position:0% +let's go back to the Bowden chapter uh + + + align:start position:0% +let's go back to the Bowden chapter uh +but from Tom I gather maybe you don't + + align:start position:0% +but from Tom I gather maybe you don't + + + align:start position:0% +but from Tom I gather maybe you don't +have to go there anything in Bodance + + align:start position:0% +have to go there anything in Bodance + + + align:start position:0% +have to go there anything in Bodance +will give you the same um explore these + + align:start position:0% +will give you the same um explore these + + + align:start position:0% +will give you the same um explore these +as three different possibilities okay + + align:start position:0% +as three different possibilities okay + + + align:start position:0% +as three different possibilities okay +that's all under the first category now + + align:start position:0% +that's all under the first category now + + + align:start position:0% +that's all under the first category now +go on yeah so I was going to say the + + align:start position:0% +go on yeah so I was going to say the + + + align:start position:0% +go on yeah so I was going to say the +second category is creativity that + + align:start position:0% +second category is creativity that + + + align:start position:0% +second category is creativity that +challenges existing ways of doing things + + align:start position:0% +challenges existing ways of doing things + + + align:start position:0% +challenges existing ways of doing things +or if you think about it um more of + + align:start position:0% +or if you think about it um more of + + + align:start position:0% +or if you think about it um more of +inventiveness opposed to well the word + + align:start position:0% +inventiveness opposed to well the word + + + align:start position:0% +inventiveness opposed to well the word +again yeah that now we're getting into + + align:start position:0% +again yeah that now we're getting into + + + align:start position:0% +again yeah that now we're getting into +the terminological problem about word + + align:start position:0% +the terminological problem about word + + + align:start position:0% +the terminological problem about word +what the word inventiveness means as + + align:start position:0% +what the word inventiveness means as + + + align:start position:0% +what the word inventiveness means as +opposed to uh creativity um um + + align:start position:0% +opposed to uh creativity um um + + + align:start position:0% +opposed to uh creativity um um +Kesler distinguishes between creativity + + align:start position:0% +Kesler distinguishes between creativity + + + align:start position:0% +Kesler distinguishes between creativity +and inventiveness too um also what + + align:start position:0% +and inventiveness too um also what + + + align:start position:0% +and inventiveness too um also what +you're saying about the um + + align:start position:0% +you're saying about the um + + + align:start position:0% +you're saying about the um +third the third the second category + + align:start position:0% +third the third the second category + + + align:start position:0% +third the third the second category +seems to the the definition that Kesler + + align:start position:0% +seems to the the definition that Kesler + + + align:start position:0% +seems to the the definition that Kesler +gives for all creativity that all + + align:start position:0% +gives for all creativity that all + + + align:start position:0% +gives for all creativity that all +creativity is the reaction against + + align:start position:0% +creativity is the reaction against + + + align:start position:0% +creativity is the reaction against +established ways of doing things. That + + align:start position:0% +established ways of doing things. That + + + align:start position:0% +established ways of doing things. That +the creativity consists in that by + + align:start position:0% +the creativity consists in that by + + + align:start position:0% +the creativity consists in that by +association. You remember that Kesla + + align:start position:0% +association. You remember that Kesla + + + align:start position:0% +association. You remember that Kesla +talks about where you take two separated + + align:start position:0% +talks about where you take two separated + + + align:start position:0% +talks about where you take two separated +methods of thinking and of and of + + align:start position:0% +methods of thinking and of and of + + + align:start position:0% +methods of thinking and of and of +imagination and you combine them two. + + align:start position:0% +imagination and you combine them two. + + + align:start position:0% +imagination and you combine them two. +you you unite them in a way that nobody + + align:start position:0% +you you unite them in a way that nobody + + + align:start position:0% +you you unite them in a way that nobody +else has done. So that would seem to fit + + align:start position:0% +else has done. So that would seem to fit + + + align:start position:0% +else has done. So that would seem to fit +the second category. Yeah. I guess that + + align:start position:0% +the second category. Yeah. I guess that + + + align:start position:0% +the second category. Yeah. I guess that +um Sternberg is more saying that um a + + align:start position:0% +um Sternberg is more saying that um a + + + align:start position:0% +um Sternberg is more saying that um a +credifying type of creativity might be + + align:start position:0% +credifying type of creativity might be + + + align:start position:0% +credifying type of creativity might be +something that's reconstructed from a + + align:start position:0% +something that's reconstructed from a + + + align:start position:0% +something that's reconstructed from a +point in the past but might not be + + align:start position:0% +point in the past but might not be + + + align:start position:0% +point in the past but might not be +something that's used in the present. + + align:start position:0% +something that's used in the present. + + + align:start position:0% +something that's used in the present. +And one of the examples that he brings + + align:start position:0% +And one of the examples that he brings + + + align:start position:0% +And one of the examples that he brings +up is the Clinton administration + + align:start position:0% +up is the Clinton administration + + + align:start position:0% +up is the Clinton administration +um trying to achieve a balanced budget, + + align:start position:0% +um trying to achieve a balanced budget, + + + align:start position:0% +um trying to achieve a balanced budget, +which although it might not seem + + align:start position:0% +which although it might not seem + + + align:start position:0% +which although it might not seem +creative, was something that hadn't been + + align:start position:0% +creative, was something that hadn't been + + + align:start position:0% +creative, was something that hadn't been +done in a long time. And basically he's + + align:start position:0% +done in a long time. And basically he's + + + align:start position:0% +done in a long time. And basically he's +arguing that that is in a sense creative + + align:start position:0% +arguing that that is in a sense creative + + + align:start position:0% +arguing that that is in a sense creative +because they were able to redirect + + align:start position:0% +because they were able to redirect + + + align:start position:0% +because they were able to redirect +um basically the direction of the + + align:start position:0% +um basically the direction of the + + + align:start position:0% +um basically the direction of the +financial state. Is this the third + + align:start position:0% +financial state. Is this the third + + + align:start position:0% +financial state. Is this the third +category? No, it's under like saying + + align:start position:0% +category? No, it's under like saying + + + align:start position:0% +category? No, it's under like saying +that this is like a crowd-defying type + + align:start position:0% +that this is like a crowd-defying type + + + align:start position:0% +that this is like a crowd-defying type +of creativity + + align:start position:0% +of creativity + + + align:start position:0% +of creativity +and he's just trying to use a lot of + + align:start position:0% +and he's just trying to use a lot of + + + align:start position:0% +and he's just trying to use a lot of +different examples. Sternberg talks + + align:start position:0% +different examples. Sternberg talks + + + align:start position:0% +different examples. Sternberg talks +about businesses. He talks about product + + align:start position:0% +about businesses. He talks about product + + + align:start position:0% +about businesses. He talks about product +design. He talks about the government. + + align:start position:0% +design. He talks about the government. + + + align:start position:0% +design. He talks about the government. +So, he's just trying to say that + + align:start position:0% +So, he's just trying to say that + + + align:start position:0% +So, he's just trying to say that +basically they were a new like their + + align:start position:0% +basically they were a new like their + + + align:start position:0% +basically they were a new like their +administration was using a new type + + align:start position:0% +administration was using a new type + + + align:start position:0% +administration was using a new type +their leadership was exemplifying a new + + align:start position:0% +their leadership was exemplifying a new + + + align:start position:0% +their leadership was exemplifying a new +type of creativity since they went back + + align:start position:0% +type of creativity since they went back + + + align:start position:0% +type of creativity since they went back +to um the era of actually making balance + + align:start position:0% +to um the era of actually making balance + + + align:start position:0% +to um the era of actually making balance +budget and that that isn't what after + + align:start position:0% +budget and that that isn't what after + + + align:start position:0% +budget and that that isn't what after +all I may have misunderstood what you're + + align:start position:0% +all I may have misunderstood what you're + + + align:start position:0% +all I may have misunderstood what you're +saying that isn't what Kesler had in + + align:start position:0% +saying that isn't what Kesler had in + + + align:start position:0% +saying that isn't what Kesler had in +mind. This is a a redirection whereas + + align:start position:0% +mind. This is a a redirection whereas + + + align:start position:0% +mind. This is a a redirection whereas +Tesla's idea is that it's a a kind of + + align:start position:0% +Tesla's idea is that it's a a kind of + + + align:start position:0% +Tesla's idea is that it's a a kind of +radical a logically radical way of + + align:start position:0% +radical a logically radical way of + + + align:start position:0% +radical a logically radical way of +combining what everyone else would have + + align:start position:0% +combining what everyone else would have + + + align:start position:0% +combining what everyone else would have +thought would be um irreconcilable + + align:start position:0% +thought would be um irreconcilable + + + align:start position:0% +thought would be um irreconcilable +differences opposites. Yeah, I was going + + align:start position:0% +differences opposites. Yeah, I was going + + + align:start position:0% +differences opposites. Yeah, I was going +to say Sternberg's third idea is + + align:start position:0% +to say Sternberg's third idea is + + + align:start position:0% +to say Sternberg's third idea is +synthesis + + align:start position:0% +synthesis + + + align:start position:0% +synthesis +and that would be more that is that + + align:start position:0% +and that would be more that is that + + + align:start position:0% +and that would be more that is that +would be what that would be more like + + align:start position:0% +would be what that would be more like + + + align:start position:0% +would be what that would be more like +what Kesler was saying is is there a + + align:start position:0% +what Kesler was saying is is there a + + + align:start position:0% +what Kesler was saying is is there a +category for that? Yeah, his third + + align:start position:0% +category for that? Yeah, his third + + + align:start position:0% +category for that? Yeah, his third +category is synthesis and that's the one + + align:start position:0% +category is synthesis and that's the one + + + align:start position:0% +category is synthesis and that's the one +that's least described obviously but a + + align:start position:0% +that's least described obviously but a + + + align:start position:0% +that's least described obviously but a +synthesis uh among uh what seemed to be + + align:start position:0% +synthesis uh among uh what seemed to be + + + align:start position:0% +synthesis uh among uh what seemed to be +irreconcilable opposites not just a + + align:start position:0% +irreconcilable opposites not just a + + + align:start position:0% +irreconcilable opposites not just a +synthesis but that particular one + + align:start position:0% +synthesis but that particular one + + + align:start position:0% +synthesis but that particular one +otherwise everyone would have thought + + align:start position:0% +otherwise everyone would have thought + + + align:start position:0% +otherwise everyone would have thought +about it but it's because it's the + + align:start position:0% +about it but it's because it's the + + + align:start position:0% +about it but it's because it's the +components seem to be irreconcilable the + + align:start position:0% +components seem to be irreconcilable the + + + align:start position:0% +components seem to be irreconcilable the +synthesis is created + + align:start position:0% +synthesis is created + + + align:start position:0% +synthesis is created +okay now okay now uh do you want to go + + align:start position:0% +okay now okay now uh do you want to go + + + align:start position:0% +okay now okay now uh do you want to go +through all of them or Uh, I mean I + + align:start position:0% +through all of them or Uh, I mean I + + + align:start position:0% +through all of them or Uh, I mean I +there should probably be enough time. I + + align:start position:0% +there should probably be enough time. I + + + align:start position:0% +there should probably be enough time. I +don't know if other people want to know. + + align:start position:0% +don't know if other people want to know. + + + align:start position:0% +don't know if other people want to know. +And um you you're you're in control. I + + align:start position:0% +And um you you're you're in control. I + + + align:start position:0% +And um you you're you're in control. I +mean you don't have any problems with + + align:start position:0% +mean you don't have any problems with + + + align:start position:0% +mean you don't have any problems with +the writing of the papers. Uh I think + + align:start position:0% +the writing of the papers. Uh I think + + + align:start position:0% +the writing of the papers. Uh I think +I'm okay. So is is there any way that we + + align:start position:0% +I'm okay. So is is there any way that we + + + align:start position:0% +I'm okay. So is is there any way that we +could be of help? + + align:start position:0% +could be of help? + + + align:start position:0% +could be of help? +Um + + align:start position:0% +Um + + + align:start position:0% +Um +I think I'm okay. Okay. Uh Mel. + + align:start position:0% + + + + align:start position:0% + +All right. So + + align:start position:0% +All right. So + + + align:start position:0% +All right. So +hi. + + align:start position:0% +hi. + + + align:start position:0% +hi. +So um as I stated before last week, I + + align:start position:0% +So um as I stated before last week, I + + + align:start position:0% +So um as I stated before last week, I +will be writing about creativity and + + align:start position:0% +will be writing about creativity and + + + align:start position:0% +will be writing about creativity and +intelligence and what role creativity + + align:start position:0% +intelligence and what role creativity + + + align:start position:0% +intelligence and what role creativity +plays in the development of intelligence + + align:start position:0% +plays in the development of intelligence + + + align:start position:0% +plays in the development of intelligence +and how that leads to creative + + align:start position:0% +and how that leads to creative + + + align:start position:0% +and how that leads to creative +intellectuals. + + align:start position:0% +intellectuals. + + + align:start position:0% +intellectuals. +And so what I'm basing I'm basing a lot + + align:start position:0% +And so what I'm basing I'm basing a lot + + + align:start position:0% +And so what I'm basing I'm basing a lot +of this on on previous research that + + align:start position:0% +of this on on previous research that + + + align:start position:0% +of this on on previous research that +I've done in the past and how the mind + + align:start position:0% +I've done in the past and how the mind + + + align:start position:0% +I've done in the past and how the mind +develops especially in infants and + + align:start position:0% +develops especially in infants and + + + align:start position:0% +develops especially in infants and +adulthood. And so one of my one of my + + align:start position:0% +adulthood. And so one of my one of my + + + align:start position:0% +adulthood. And so one of my one of my +claims which is actually I would say the + + align:start position:0% +claims which is actually I would say the + + + align:start position:0% +claims which is actually I would say the +most important claim that I make is that + + align:start position:0% +most important claim that I make is that + + + align:start position:0% +most important claim that I make is that +creativity is a native function to all + + align:start position:0% +creativity is a native function to all + + + align:start position:0% +creativity is a native function to all +humans and that in order for any type of + + align:start position:0% +humans and that in order for any type of + + + align:start position:0% +humans and that in order for any type of +intellectual development to take place + + align:start position:0% +intellectual development to take place + + + align:start position:0% +intellectual development to take place +creativity must be an innate ability of + + align:start position:0% +creativity must be an innate ability of + + + align:start position:0% +creativity must be an innate ability of +our mind. And the reason I say this is + + align:start position:0% +our mind. And the reason I say this is + + + align:start position:0% +our mind. And the reason I say this is +because + + align:start position:0% +because + + + align:start position:0% +because +it is defined by James Russell L that + + align:start position:0% +it is defined by James Russell L that + + + align:start position:0% +it is defined by James Russell L that +creativity is not the finding of a thing + + align:start position:0% +creativity is not the finding of a thing + + + align:start position:0% +creativity is not the finding of a thing +but the making something out of it after + + align:start position:0% +but the making something out of it after + + + align:start position:0% +but the making something out of it after +it is found. And so from that I'm going + + align:start position:0% +it is found. And so from that I'm going + + + align:start position:0% +it is found. And so from that I'm going +to use that definition as the basis for + + align:start position:0% +to use that definition as the basis for + + + align:start position:0% +to use that definition as the basis for +the creating of new concepts that a + + align:start position:0% +the creating of new concepts that a + + + align:start position:0% +the creating of new concepts that a +person will go through throughout life + + align:start position:0% +person will go through throughout life + + + align:start position:0% +person will go through throughout life +making sense of the world from his or + + align:start position:0% +making sense of the world from his or + + + align:start position:0% +making sense of the world from his or +her experiences. Um let me interrupt + + align:start position:0% +her experiences. Um let me interrupt + + + align:start position:0% +her experiences. Um let me interrupt +you. Uh, Lel F that Lel was a poet and + + align:start position:0% +you. Uh, Lel F that Lel was a poet and + + + align:start position:0% +you. Uh, Lel F that Lel was a poet and +it's a poetic statement. Uh, I don't + + align:start position:0% +it's a poetic statement. Uh, I don't + + + align:start position:0% +it's a poetic statement. Uh, I don't +know exactly what it means and I don't + + align:start position:0% +know exactly what it means and I don't + + + align:start position:0% +know exactly what it means and I don't +have to and you don't have to, but + + align:start position:0% +have to and you don't have to, but + + + align:start position:0% +have to and you don't have to, but +putting too much weight on it. Do you + + align:start position:0% +putting too much weight on it. Do you + + + align:start position:0% +putting too much weight on it. Do you +Well, no, no, no. That's not that's not + + align:start position:0% +Well, no, no, no. That's not that's not + + + align:start position:0% +Well, no, no, no. That's not that's not +what I was basing it off of. I'm just + + align:start position:0% +what I was basing it off of. I'm just + + + align:start position:0% +what I was basing it off of. I'm just +That's I found that actually I just + + align:start position:0% +That's I found that actually I just + + + align:start position:0% +That's I found that actually I just +found that earlier today that actually + + align:start position:0% +found that earlier today that actually + + + align:start position:0% +found that earlier today that actually +supports. Okay, that's fine. But um + + align:start position:0% +supports. Okay, that's fine. But um + + + align:start position:0% +supports. Okay, that's fine. But um +also I was going like I said I was using + + align:start position:0% +also I was going like I said I was using + + + align:start position:0% +also I was going like I said I was using +creativity as an innate ability of all + + align:start position:0% +creativity as an innate ability of all + + + align:start position:0% +creativity as an innate ability of all +human beings and it's from this innate + + align:start position:0% +human beings and it's from this innate + + + align:start position:0% +human beings and it's from this innate +ability we're able to conceptualize and + + align:start position:0% +ability we're able to conceptualize and + + + align:start position:0% +ability we're able to conceptualize and +thus + + align:start position:0% +thus + + + align:start position:0% +thus +form our mental cognition + + align:start position:0% +form our mental cognition + + + align:start position:0% +form our mental cognition +and + + align:start position:0% +and + + + align:start position:0% +and +I have some sources and also I've known + + align:start position:0% +I have some sources and also I've known + + + align:start position:0% +I have some sources and also I've known +this from past research is that + + align:start position:0% +this from past research is that + + + align:start position:0% +this from past research is that +it is seems to be the case that more + + align:start position:0% +it is seems to be the case that more + + + align:start position:0% +it is seems to be the case that more +intellectual ual people tend to be more + + align:start position:0% +intellectual ual people tend to be more + + + align:start position:0% +intellectual ual people tend to be more +creative than well, let me phrase that. + + align:start position:0% +creative than well, let me phrase that. + + + align:start position:0% +creative than well, let me phrase that. +Above average intellect persons tend to + + align:start position:0% +Above average intellect persons tend to + + + align:start position:0% +Above average intellect persons tend to +be more creative than average intellect + + align:start position:0% +be more creative than average intellect + + + align:start position:0% +be more creative than average intellect +persons. Now, I'm still looking digging + + align:start position:0% +persons. Now, I'm still looking digging + + + align:start position:0% +persons. Now, I'm still looking digging +into what that's based off of, but there + + align:start position:0% +into what that's based off of, but there + + + align:start position:0% +into what that's based off of, but there +is a correlation between creativity and + + align:start position:0% +is a correlation between creativity and + + + align:start position:0% +is a correlation between creativity and +intelligence. And so from that I deduced + + align:start position:0% +intelligence. And so from that I deduced + + + align:start position:0% +intelligence. And so from that I deduced +that creativity + + align:start position:0% +that creativity + + + align:start position:0% +that creativity +is not is as stated an innate ability + + align:start position:0% +is not is as stated an innate ability + + + align:start position:0% +is not is as stated an innate ability +such as language and can be practiced. + + align:start position:0% +such as language and can be practiced. + + + align:start position:0% +such as language and can be practiced. +And from that I deduced that everyone + + align:start position:0% +And from that I deduced that everyone + + + align:start position:0% +And from that I deduced that everyone +has the potential to be a genius because + + align:start position:0% +has the potential to be a genius because + + + align:start position:0% +has the potential to be a genius because +as life goes on you keep practicing this + + align:start position:0% +as life goes on you keep practicing this + + + align:start position:0% +as life goes on you keep practicing this +create this creative process and + + align:start position:0% +create this creative process and + + + align:start position:0% +create this creative process and +creating new concepts. And so from that + + align:start position:0% +creating new concepts. And so from that + + + align:start position:0% +creating new concepts. And so from that +I argue that the uh disparity between + + align:start position:0% +I argue that the uh disparity between + + + align:start position:0% +I argue that the uh disparity between +intellectuals and non-intellectuals + + align:start position:0% +intellectuals and non-intellectuals + + + align:start position:0% +intellectuals and non-intellectuals +is not the basis of genetics but more of + + align:start position:0% +is not the basis of genetics but more of + + + align:start position:0% +is not the basis of genetics but more of +nurturing because of that creative + + align:start position:0% +nurturing because of that creative + + + align:start position:0% +nurturing because of that creative +process has not been nurtured as much as + + align:start position:0% +process has not been nurtured as much as + + + align:start position:0% +process has not been nurtured as much as +someone else who has had who has a + + align:start position:0% +someone else who has had who has a + + + align:start position:0% +someone else who has had who has a +higher IQ. So I would say that a person, + + align:start position:0% +higher IQ. So I would say that a person, + + + align:start position:0% +higher IQ. So I would say that a person, +let's say you have two children, for + + align:start position:0% +let's say you have two children, for + + + align:start position:0% +let's say you have two children, for +example, two children in a neighborhood + + align:start position:0% +example, two children in a neighborhood + + + align:start position:0% +example, two children in a neighborhood +and + + align:start position:0% +and + + + align:start position:0% +and +at the age of eight, they're roughly the + + align:start position:0% +at the age of eight, they're roughly the + + + align:start position:0% +at the age of eight, they're roughly the +same intelligence, but one grows up to + + align:start position:0% +same intelligence, but one grows up to + + + align:start position:0% +same intelligence, but one grows up to +be a professor and the other grows up to + + align:start position:0% +be a professor and the other grows up to + + + align:start position:0% +be a professor and the other grows up to +be a manager of McDonald's. And I would + + align:start position:0% +be a manager of McDonald's. And I would + + + align:start position:0% +be a manager of McDonald's. And I would +argue that the reason why this one grew + + align:start position:0% +argue that the reason why this one grew + + + align:start position:0% +argue that the reason why this one grew +up into being a professor is because he + + align:start position:0% +up into being a professor is because he + + + align:start position:0% +up into being a professor is because he +had more practice in creating new + + align:start position:0% +had more practice in creating new + + + align:start position:0% +had more practice in creating new +concepts. he was exposed to more things + + align:start position:0% +concepts. he was exposed to more things + + + align:start position:0% +concepts. he was exposed to more things +that caused that forced him in order to + + align:start position:0% +that caused that forced him in order to + + + align:start position:0% +that caused that forced him in order to +make sense of the world to be more + + align:start position:0% +make sense of the world to be more + + + align:start position:0% +make sense of the world to be more +creative than the person who was a + + align:start position:0% +creative than the person who was a + + + align:start position:0% +creative than the person who was a +manager at McDonald's. And so from that + + align:start position:0% +manager at McDonald's. And so from that + + + align:start position:0% +manager at McDonald's. And so from that +I go into one of the main questions that + + align:start position:0% +I go into one of the main questions that + + + align:start position:0% +I go into one of the main questions that +has bothered me for a long time is why + + align:start position:0% +has bothered me for a long time is why + + + align:start position:0% +has bothered me for a long time is why +is there such a disparity between + + align:start position:0% +is there such a disparity between + + + align:start position:0% +is there such a disparity between +geniuses and mentally people? + + align:start position:0% +geniuses and mentally people? + + + align:start position:0% +geniuses and mentally people? +And the reason I asked this is because + + align:start position:0% +And the reason I asked this is because + + + align:start position:0% +And the reason I asked this is because +if what I'm saying is true such that + + align:start position:0% +if what I'm saying is true such that + + + align:start position:0% +if what I'm saying is true such that +creativity is an innate ability that can + + align:start position:0% +creativity is an innate ability that can + + + align:start position:0% +creativity is an innate ability that can +be practiced practiced and strengthened + + align:start position:0% +be practiced practiced and strengthened + + + align:start position:0% +be practiced practiced and strengthened +just as language or any other ability or + + align:start position:0% +just as language or any other ability or + + + align:start position:0% +just as language or any other ability or +kinesthetic intelligence it can be + + align:start position:0% +kinesthetic intelligence it can be + + + align:start position:0% +kinesthetic intelligence it can be +strengthened with practice and + + align:start position:0% +strengthened with practice and + + + align:start position:0% +strengthened with practice and +repetition. Why is it that for mentally + + align:start position:0% +repetition. Why is it that for mentally + + + align:start position:0% +repetition. Why is it that for mentally + persons that even with + + align:start position:0% + persons that even with + + + align:start position:0% + persons that even with +extensive extensive practice and + + align:start position:0% +extensive extensive practice and + + + align:start position:0% +extensive extensive practice and +repetition it is still the process of + + align:start position:0% +repetition it is still the process of + + + align:start position:0% +repetition it is still the process of +creating new concept is still slow. is + + align:start position:0% +creating new concept is still slow. is + + + align:start position:0% +creating new concept is still slow. is +still delayed and they never seem to be + + align:start position:0% +still delayed and they never seem to be + + + align:start position:0% +still delayed and they never seem to be +able to reach that level of even average + + align:start position:0% +able to reach that level of even average + + + align:start position:0% +able to reach that level of even average +intellect. And so that's what I'm going + + align:start position:0% +intellect. And so that's what I'm going + + + align:start position:0% +intellect. And so that's what I'm going +into. Well, the point are you starting + + align:start position:0% +into. Well, the point are you starting + + + align:start position:0% +into. Well, the point are you starting +out with the premise that it is innate + + align:start position:0% +out with the premise that it is innate + + + align:start position:0% +out with the premise that it is innate +in the sense that in it's innate to the + + align:start position:0% +in the sense that in it's innate to the + + + align:start position:0% +in the sense that in it's innate to the +human race and everybody is equally + + align:start position:0% +human race and everybody is equally + + + align:start position:0% +human race and everybody is equally +endowed. + + align:start position:0% +endowed. + + + align:start position:0% +endowed. +That's part of my arguments. Yeah. I + + align:start position:0% +That's part of my arguments. Yeah. I + + + align:start position:0% +That's part of my arguments. Yeah. I +would say I would say with the + + align:start position:0% +would say I would say with the + + + align:start position:0% +would say I would say with the +exceptions of born geniuses and mentally + + align:start position:0% +exceptions of born geniuses and mentally + + + align:start position:0% +exceptions of born geniuses and mentally + people, I would say yes. Okay. + + align:start position:0% + people, I would say yes. Okay. + + + align:start position:0% + people, I would say yes. Okay. +Now, how do you explain those those two + + align:start position:0% +Now, how do you explain those those two + + + align:start position:0% +Now, how do you explain those those two +two kinds of of exceptions? That's what + + align:start position:0% +two kinds of of exceptions? That's what + + + align:start position:0% +two kinds of of exceptions? That's what +I'm researching right now. Also, if um + + align:start position:0% +I'm researching right now. Also, if um + + + align:start position:0% +I'm researching right now. Also, if um +as we know in many areas there are + + align:start position:0% +as we know in many areas there are + + + align:start position:0% +as we know in many areas there are +talents, aptitudes talk about that as + + align:start position:0% +talents, aptitudes talk about that as + + + align:start position:0% +talents, aptitudes talk about that as +well as that come from the genes. That's + + align:start position:0% +well as that come from the genes. That's + + + align:start position:0% +well as that come from the genes. That's +what I mean. Well, why wouldn't the + + align:start position:0% +what I mean. Well, why wouldn't the + + + align:start position:0% +what I mean. Well, why wouldn't the +creativity also be limited by the genes + + align:start position:0% +creativity also be limited by the genes + + + align:start position:0% +creativity also be limited by the genes +that we inherit? That's true. But at the + + align:start position:0% +that we inherit? That's true. But at the + + + align:start position:0% +that we inherit? That's true. But at the +same time it I may be genetically predis + + align:start position:0% +same time it I may be genetically predis + + + align:start position:0% +same time it I may be genetically predis +I may be genetically disposed and predis + + align:start position:0% +I may be genetically disposed and predis + + + align:start position:0% +I may be genetically disposed and predis +what is that predisposed there we go um + + align:start position:0% +what is that predisposed there we go um + + + align:start position:0% +what is that predisposed there we go um +I may be genetically predisposed to have + + align:start position:0% +I may be genetically predisposed to have + + + align:start position:0% +I may be genetically predisposed to have +a knack for physics but that does not + + align:start position:0% +a knack for physics but that does not + + + align:start position:0% +a knack for physics but that does not +mean that I cannot develop other mental + + align:start position:0% +mean that I cannot develop other mental + + + align:start position:0% +mean that I cannot develop other mental +faculties to that same level now wait a + + align:start position:0% +faculties to that same level now wait a + + + align:start position:0% +faculties to that same level now wait a +minute a knack is what you're + + align:start position:0% +minute a knack is what you're + + + align:start position:0% +minute a knack is what you're +predisposed to that's genetic genetic + + align:start position:0% +predisposed to that's genetic genetic + + + align:start position:0% +predisposed to that's genetic genetic +now What what does that knock? No, I + + align:start position:0% +now What what does that knock? No, I + + + align:start position:0% +now What what does that knock? No, I +mean genetically I'm predisposed to have + + align:start position:0% +mean genetically I'm predisposed to have + + + align:start position:0% +mean genetically I'm predisposed to have +a gift in physics. No, but that I mean + + align:start position:0% +a gift in physics. No, but that I mean + + + align:start position:0% +a gift in physics. No, but that I mean +what goes into that? Why I mean that + + align:start position:0% +what goes into that? Why I mean that + + + align:start position:0% +what goes into that? Why I mean that +seems very high level to choose physics? + + align:start position:0% +seems very high level to choose physics? + + + align:start position:0% +seems very high level to choose physics? +What I mean what do you have to be in + + align:start position:0% +What I mean what do you have to be in + + + align:start position:0% +What I mean what do you have to be in +order to be a physicist? Why know take + + align:start position:0% +order to be a physicist? Why know take + + + align:start position:0% +order to be a physicist? Why know take +make it a little easier or more obvious. + + align:start position:0% +make it a little easier or more obvious. + + + align:start position:0% +make it a little easier or more obvious. +Um let's say that you have a knack to be + + align:start position:0% +Um let's say that you have a knack to be + + + align:start position:0% +Um let's say that you have a knack to be +a pianist. + + align:start position:0% +a pianist. + + + align:start position:0% +a pianist. +Now what does that mean? Means I would + + align:start position:0% +Now what does that mean? Means I would + + + align:start position:0% +Now what does that mean? Means I would +interpret that as genetically you have + + align:start position:0% +interpret that as genetically you have + + + align:start position:0% +interpret that as genetically you have +the qualities and abilities in order so + + align:start position:0% +the qualities and abilities in order so + + + align:start position:0% +the qualities and abilities in order so +such that the act of playing a piano is + + align:start position:0% +such that the act of playing a piano is + + + align:start position:0% +such that the act of playing a piano is +more natural for you than that of + + align:start position:0% +more natural for you than that of + + + align:start position:0% +more natural for you than that of +another. Now would that be true of + + align:start position:0% +another. Now would that be true of + + + align:start position:0% +another. Now would that be true of +everybody? No. But what I'm saying is + + align:start position:0% +everybody? No. But what I'm saying is + + + align:start position:0% +everybody? No. But what I'm saying is +because of this inability to create new + + align:start position:0% +because of this inability to create new + + + align:start position:0% +because of this inability to create new +concepts that everyone given sufficient + + align:start position:0% +concepts that everyone given sufficient + + + align:start position:0% +concepts that everyone given sufficient +repetition at work can work up to that + + align:start position:0% +repetition at work can work up to that + + + align:start position:0% +repetition at work can work up to that +level. Everyone could. Yes. That's + + align:start position:0% +level. Everyone could. Yes. That's + + + align:start position:0% +level. Everyone could. Yes. That's +that's what I'm saying. you're you're + + align:start position:0% +that's what I'm saying. you're you're + + + align:start position:0% +that's what I'm saying. you're you're +putting creativity as an independent + + align:start position:0% +putting creativity as an independent + + + align:start position:0% +putting creativity as an independent +sort of function of the brain as opposed + + align:start position:0% +sort of function of the brain as opposed + + + align:start position:0% +sort of function of the brain as opposed +to learning or uh that there there is in + + align:start position:0% +to learning or uh that there there is in + + + align:start position:0% +to learning or uh that there there is in +every area of life + + align:start position:0% +every area of life + + + align:start position:0% +every area of life +um that innate potentiality. I would say + + align:start position:0% +um that innate potentiality. I would say + + + align:start position:0% +um that innate potentiality. I would say +yes because I would say that there I + + align:start position:0% +yes because I would say that there I + + + align:start position:0% +yes because I would say that there I +would say that the there is no mental + + align:start position:0% +would say that the there is no mental + + + align:start position:0% +would say that the there is no mental +limit to what a person is capable of + + align:start position:0% +limit to what a person is capable of + + + align:start position:0% +limit to what a person is capable of +doing. I mean, I would say that the + + align:start position:0% +doing. I mean, I would say that the + + + align:start position:0% +doing. I mean, I would say that the +reason like I play the saxophone. The + + align:start position:0% +reason like I play the saxophone. The + + + align:start position:0% +reason like I play the saxophone. The +reason why I would never ever be as + + align:start position:0% +reason why I would never ever be as + + + align:start position:0% +reason why I would never ever be as +great as say Charlie Parker is because I + + align:start position:0% +great as say Charlie Parker is because I + + + align:start position:0% +great as say Charlie Parker is because I +don't play as much as he does. Charlie + + align:start position:0% +don't play as much as he does. Charlie + + + align:start position:0% +don't play as much as he does. Charlie +Parker played from every waking moment + + align:start position:0% +Parker played from every waking moment + + + align:start position:0% +Parker played from every waking moment +of of his life. The time he woke up to + + align:start position:0% +of of his life. The time he woke up to + + + align:start position:0% +of of his life. The time he woke up to +the time he went to sleep, unless he was + + align:start position:0% +the time he went to sleep, unless he was + + + align:start position:0% +the time he went to sleep, unless he was +doing drugs, but all the time he was + + align:start position:0% +doing drugs, but all the time he was + + + align:start position:0% +doing drugs, but all the time he was +playing. As with I I play maybe an hour, + + align:start position:0% +playing. As with I I play maybe an hour, + + + align:start position:0% +playing. As with I I play maybe an hour, +a week or two. So because if if I were + + align:start position:0% +a week or two. So because if if I were + + + align:start position:0% +a week or two. So because if if I were +to play that intensely as Charlie + + align:start position:0% +to play that intensely as Charlie + + + align:start position:0% +to play that intensely as Charlie +Parker, I do not feel that there's any + + align:start position:0% +Parker, I do not feel that there's any + + + align:start position:0% +Parker, I do not feel that there's any +reason why I would not be able to get to + + align:start position:0% +reason why I would not be able to get to + + + align:start position:0% +reason why I would not be able to get to +that level. I wouldn't question that for + + align:start position:0% +that level. I wouldn't question that for + + + align:start position:0% +that level. I wouldn't question that for +a moment about you because I don't know. + + align:start position:0% +a moment about you because I don't know. + + + align:start position:0% +a moment about you because I don't know. +But uh I can't believe that that would + + align:start position:0% +But uh I can't believe that that would + + + align:start position:0% +But uh I can't believe that that would +be true of everybody that if only you + + align:start position:0% +be true of everybody that if only you + + + align:start position:0% +be true of everybody that if only you +know somebody + + align:start position:0% +know somebody + + + align:start position:0% +know somebody +in the population were picked up and + + align:start position:0% +in the population were picked up and + + + align:start position:0% +in the population were picked up and +forced or encouraged and who liked even + + align:start position:0% +forced or encouraged and who liked even + + + align:start position:0% +forced or encouraged and who liked even +to play as much as Charlie Parker did + + align:start position:0% +to play as much as Charlie Parker did + + + align:start position:0% +to play as much as Charlie Parker did +that he would ever play as well. So in + + align:start position:0% +that he would ever play as well. So in + + + align:start position:0% +that he would ever play as well. So in +that sense that's that's like the + + align:start position:0% +that sense that's that's like the + + + align:start position:0% +that sense that's that's like the +monkeys uh being put into the typewriter + + align:start position:0% +monkeys uh being put into the typewriter + + + align:start position:0% +monkeys uh being put into the typewriter +and ending up with the works of + + align:start position:0% +and ending up with the works of + + + align:start position:0% +and ending up with the works of +Shakespeare. I mean, you have it has to + + align:start position:0% +Shakespeare. I mean, you have it has to + + + align:start position:0% +Shakespeare. I mean, you have it has to +be more than just this application of + + align:start position:0% +be more than just this application of + + + align:start position:0% +be more than just this application of +the seat of the pants to the seat of the + + align:start position:0% +the seat of the pants to the seat of the + + + align:start position:0% +the seat of the pants to the seat of the +of the of the chair. That actually gives + + align:start position:0% +of the of the chair. That actually gives + + + align:start position:0% +of the of the chair. That actually gives +me a good argument for why it was + + align:start position:0% +me a good argument for why it was + + + align:start position:0% +me a good argument for why it was +genetic as well. How well you're able to + + align:start position:0% +genetic as well. How well you're able to + + + align:start position:0% +genetic as well. How well you're able to +create these new the concepts. Yes. + + align:start position:0% +create these new the concepts. Yes. + + + align:start position:0% +create these new the concepts. Yes. +What's what's the concept? + + align:start position:0% +What's what's the concept? + + + align:start position:0% +What's what's the concept? +I would say these concepts of these + + align:start position:0% +I would say these concepts of these + + + align:start position:0% +I would say these concepts of these +practices, these abilities. Oh, that + + align:start position:0% +practices, these abilities. Oh, that + + + align:start position:0% +practices, these abilities. Oh, that +they're different from concepts. Your + + align:start position:0% +they're different from concepts. Your + + + align:start position:0% +they're different from concepts. Your +ability to be creative in these was in + + align:start position:0% +ability to be creative in these was in + + + align:start position:0% +ability to be creative in these was in +these abilities, right? Well, when I say + + align:start position:0% +these abilities, right? Well, when I say + + + align:start position:0% +these abilities, right? Well, when I say +creative, I'm not strictly prevent I'm + + align:start position:0% +creative, I'm not strictly prevent I'm + + + align:start position:0% +creative, I'm not strictly prevent I'm +not strictly speaking about the arts. + + align:start position:0% +not strictly speaking about the arts. + + + align:start position:0% +not strictly speaking about the arts. +I'm speaking about like everyday life + + align:start position:0% +I'm speaking about like everyday life + + + align:start position:0% +I'm speaking about like everyday life +and particularly intelligence, the + + align:start position:0% +and particularly intelligence, the + + + align:start position:0% +and particularly intelligence, the +different faculties of intelligence. So + + align:start position:0% +different faculties of intelligence. So + + + align:start position:0% +different faculties of intelligence. So +it's just like some people + + align:start position:0% +it's just like some people + + + align:start position:0% +it's just like some people +I would argue that some people I would + + align:start position:0% +I would argue that some people I would + + + align:start position:0% +I would argue that some people I would +argue that everyone has the ability to + + align:start position:0% +argue that everyone has the ability to + + + align:start position:0% +argue that everyone has the ability to +create innately but I would say that for + + align:start position:0% +create innately but I would say that for + + + align:start position:0% +create innately but I would say that for +some people that ability is stronger + + align:start position:0% +some people that ability is stronger + + + align:start position:0% +some people that ability is stronger +than others and their lives that + + align:start position:0% +than others and their lives that + + + align:start position:0% +than others and their lives that +disparity between those strengths is the + + align:start position:0% +disparity between those strengths is the + + + align:start position:0% +disparity between those strengths is the +disparity between genius and mentally + + align:start position:0% +disparity between genius and mentally + + + align:start position:0% +disparity between genius and mentally + But it it looks if you it + + align:start position:0% + But it it looks if you it + + + align:start position:0% + But it it looks if you it +seems like a truism if all you're saying + + align:start position:0% +seems like a truism if all you're saying + + + align:start position:0% +seems like a truism if all you're saying +is to some degree however slight + + align:start position:0% +is to some degree however slight + + + align:start position:0% +is to some degree however slight +everybody can be creative because that + + align:start position:0% +everybody can be creative because that + + + align:start position:0% +everybody can be creative because that +is sort of innocuous. You could say that + + align:start position:0% +is sort of innocuous. You could say that + + + align:start position:0% +is sort of innocuous. You could say that +because it doesn't matter. You know he + + align:start position:0% +because it doesn't matter. You know he + + + align:start position:0% +because it doesn't matter. You know he +has a little ability but he isn't a + + align:start position:0% +has a little ability but he isn't a + + + align:start position:0% +has a little ability but he isn't a +creative person because that amount is + + align:start position:0% +creative person because that amount is + + + align:start position:0% +creative person because that amount is +so small. No, I would say the + + align:start position:0% +so small. No, I would say the + + + align:start position:0% +so small. No, I would say the +interesting question would be if + + align:start position:0% +interesting question would be if + + + align:start position:0% +interesting question would be if +everybody has a comparable ability. I + + align:start position:0% +everybody has a comparable ability. I + + + align:start position:0% +everybody has a comparable ability. I +would say everyone of average intellect + + align:start position:0% +would say everyone of average intellect + + + align:start position:0% +would say everyone of average intellect +has a comparable ability because it + + align:start position:0% +has a comparable ability because it + + + align:start position:0% +has a comparable ability because it +requires based on my claim that + + align:start position:0% +requires based on my claim that + + + align:start position:0% +requires based on my claim that +creativity is required for intellectual + + align:start position:0% +creativity is required for intellectual + + + align:start position:0% +creativity is required for intellectual +development. In order to get to a point + + align:start position:0% +development. In order to get to a point + + + align:start position:0% +development. In order to get to a point +of self being able to live in this world + + align:start position:0% +of self being able to live in this world + + + align:start position:0% +of self being able to live in this world +self- sustained, you have to have a + + align:start position:0% +self- sustained, you have to have a + + + align:start position:0% +self- sustained, you have to have a +certain level of intelligence and from + + align:start position:0% +certain level of intelligence and from + + + align:start position:0% +certain level of intelligence and from +that creativity you are born with. You + + align:start position:0% +that creativity you are born with. You + + + align:start position:0% +that creativity you are born with. You +create the concepts required or create + + align:start position:0% +create the concepts required or create + + + align:start position:0% +create the concepts required or create +abilities or intelligence whatever part + + align:start position:0% +abilities or intelligence whatever part + + + align:start position:0% +abilities or intelligence whatever part +whatever faculty of life required in + + align:start position:0% +whatever faculty of life required in + + + align:start position:0% +whatever faculty of life required in +order to live your life at the bare at + + align:start position:0% +order to live your life at the bare at + + + align:start position:0% +order to live your life at the bare at +the bare minimum. It does. Well, I I I + + align:start position:0% +the bare minimum. It does. Well, I I I + + + align:start position:0% +the bare minimum. It does. Well, I I I +think I understand what you're saying, + + align:start position:0% +think I understand what you're saying, + + + align:start position:0% +think I understand what you're saying, +but it seems strange to + + align:start position:0% +but it seems strange to + + + align:start position:0% +but it seems strange to +treat the great j gen geniuses of this + + align:start position:0% +treat the great j gen geniuses of this + + + align:start position:0% +treat the great j gen geniuses of this +world in any field uh as sort of being + + align:start position:0% +world in any field uh as sort of being + + + align:start position:0% +world in any field uh as sort of being +um on the same level or on a par with + + align:start position:0% +um on the same level or on a par with + + + align:start position:0% +um on the same level or on a par with +ordinary mortals like ordinary mortals + + align:start position:0% +ordinary mortals like ordinary mortals + + + align:start position:0% +ordinary mortals like ordinary mortals +like most of us. You know, when I think + + align:start position:0% +like most of us. You know, when I think + + + align:start position:0% +like most of us. You know, when I think +of um people like Johan Sebastian Bach + + align:start position:0% +of um people like Johan Sebastian Bach + + + align:start position:0% +of um people like Johan Sebastian Bach +or um uh uh Emanuel Kant + + align:start position:0% +or um uh uh Emanuel Kant + + + align:start position:0% +or um uh uh Emanuel Kant +or Vitkinstein or any number of great + + align:start position:0% +or Vitkinstein or any number of great + + + align:start position:0% +or Vitkinstein or any number of great +philosophers + + align:start position:0% +philosophers + + + align:start position:0% +philosophers +or um um people like Picasso, + + align:start position:0% +or um um people like Picasso, + + + align:start position:0% +or um um people like Picasso, +there's something more that they their + + align:start position:0% +there's something more that they their + + + align:start position:0% +there's something more that they their +genius sort of exceeds anything I could + + align:start position:0% +genius sort of exceeds anything I could + + + align:start position:0% +genius sort of exceeds anything I could +ever approximate. I stand in awe of them + + align:start position:0% +ever approximate. I stand in awe of them + + + align:start position:0% +ever approximate. I stand in awe of them +and it's not because I don't want to be + + align:start position:0% +and it's not because I don't want to be + + + align:start position:0% +and it's not because I don't want to be +one of them or apply myself. It's + + align:start position:0% +one of them or apply myself. It's + + + align:start position:0% +one of them or apply myself. It's +because there is something in their + + align:start position:0% +because there is something in their + + + align:start position:0% +because there is something in their +powers of perception, something in maybe + + align:start position:0% +powers of perception, something in maybe + + + align:start position:0% +powers of perception, something in maybe +the genes, something in their very + + align:start position:0% +the genes, something in their very + + + align:start position:0% +the genes, something in their very +unique + + align:start position:0% +unique + + + align:start position:0% +unique +lifyle + + align:start position:0% +lifyle + + + align:start position:0% +lifyle +that I can't approximate no matter if + + align:start position:0% +that I can't approximate no matter if + + + align:start position:0% +that I can't approximate no matter if +any more than I could run a four mile uh + + align:start position:0% +any more than I could run a four mile uh + + + align:start position:0% +any more than I could run a four mile uh +um + + align:start position:0% +um + + + align:start position:0% +um +the mile in four minutes. Um, it's + + align:start position:0% +the mile in four minutes. Um, it's + + + align:start position:0% +the mile in four minutes. Um, it's +simply not in my reperatory. I'm not + + align:start position:0% +simply not in my reperatory. I'm not + + + align:start position:0% +simply not in my reperatory. I'm not +programmed for that to be a possibility. + + align:start position:0% +programmed for that to be a possibility. + + + align:start position:0% +programmed for that to be a possibility. +So, it is the idea of dragging them down + + align:start position:0% +So, it is the idea of dragging them down + + + align:start position:0% +So, it is the idea of dragging them down +to my level. Well, seems seems very + + align:start position:0% +to my level. Well, seems seems very + + + align:start position:0% +to my level. Well, seems seems very +questionable. I'm not dragging them + + align:start position:0% +questionable. I'm not dragging them + + + align:start position:0% +questionable. I'm not dragging them +down. I'm actually It's those people + + align:start position:0% +down. I'm actually It's those people + + + align:start position:0% +down. I'm actually It's those people +that I'm those are the anomalies and + + align:start position:0% +that I'm those are the anomalies and + + + align:start position:0% +that I'm those are the anomalies and +that's what I'm trying to explain. The + + align:start position:0% +that's what I'm trying to explain. The + + + align:start position:0% +that's what I'm trying to explain. The +geniuses and the mentally + + align:start position:0% +geniuses and the mentally + + + align:start position:0% +geniuses and the mentally +Those are the anomalies to those to that + + align:start position:0% +Those are the anomalies to those to that + + + align:start position:0% +Those are the anomalies to those to that +innate ability that we all share. But + + align:start position:0% +innate ability that we all share. But + + + align:start position:0% +innate ability that we all share. But +but I also don't think that we have I + + align:start position:0% +but I also don't think that we have I + + + align:start position:0% +but I also don't think that we have I +mean it's not clear to me that the + + align:start position:0% +mean it's not clear to me that the + + + align:start position:0% +mean it's not clear to me that the +difference between uh me and Picasso is + + align:start position:0% +difference between uh me and Picasso is + + + align:start position:0% +difference between uh me and Picasso is +one that's actually objective. Uh I I + + align:start position:0% +one that's actually objective. Uh I I + + + align:start position:0% +one that's actually objective. Uh I I +think it's much fuzzier than that. So it + + align:start position:0% +think it's much fuzzier than that. So it + + + align:start position:0% +think it's much fuzzier than that. So it +it it + + align:start position:0% +it it + + + align:start position:0% +it it +depends a lot on how much weight you put + + align:start position:0% +depends a lot on how much weight you put + + + align:start position:0% +depends a lot on how much weight you put +on, for example, whether Picasso + + align:start position:0% +on, for example, whether Picasso + + + align:start position:0% +on, for example, whether Picasso +actually, you know, deserves credit for + + align:start position:0% +actually, you know, deserves credit for + + + align:start position:0% +actually, you know, deserves credit for +it or whether it was simply his + + align:start position:0% +it or whether it was simply his + + + align:start position:0% +it or whether it was simply his +environment that produced it. It those + + align:start position:0% +environment that produced it. It those + + + align:start position:0% +environment that produced it. It those +sorts of questions, I think, undermine + + align:start position:0% +sorts of questions, I think, undermine + + + align:start position:0% +sorts of questions, I think, undermine +the the guaranteed value of that kind of + + align:start position:0% +the the guaranteed value of that kind of + + + align:start position:0% +the the guaranteed value of that kind of +differentiation and an argument. So I + + align:start position:0% +differentiation and an argument. So I + + + align:start position:0% +differentiation and an argument. So I +wouldn't say that it's clear how + + align:start position:0% +wouldn't say that it's clear how + + + align:start position:0% +wouldn't say that it's clear how +different Picasso is from me on some, + + align:start position:0% +different Picasso is from me on some, + + + align:start position:0% +different Picasso is from me on some, +you know, clear standard. I think he's + + align:start position:0% +you know, clear standard. I think he's + + + align:start position:0% +you know, clear standard. I think he's +done very different things than me. But + + align:start position:0% +done very different things than me. But + + + align:start position:0% +done very different things than me. But +it it's not I I don't feel like you can + + align:start position:0% +it it's not I I don't feel like you can + + + align:start position:0% +it it's not I I don't feel like you can +say he's just simply qualitatively + + align:start position:0% +say he's just simply qualitatively + + + align:start position:0% +say he's just simply qualitatively +different from me based on, you know, on + + align:start position:0% +different from me based on, you know, on + + + align:start position:0% +different from me based on, you know, on +this well-reasoned argument because we + + align:start position:0% +this well-reasoned argument because we + + + align:start position:0% +this well-reasoned argument because we +have no way of actually measuring that + + align:start position:0% +have no way of actually measuring that + + + align:start position:0% +have no way of actually measuring that +outside of the the social values and and + + align:start position:0% +outside of the the social values and and + + + align:start position:0% +outside of the the social values and and +culture that we bring to the the + + align:start position:0% +culture that we bring to the the + + + align:start position:0% +culture that we bring to the the +exercise. + + align:start position:0% +exercise. + + + align:start position:0% +exercise. +I don't know if that made sense. + + align:start position:0% + + + + align:start position:0% + +I'm guessing not. + + align:start position:0% +I'm guessing not. + + + align:start position:0% +I'm guessing not. +Basically, I well, I'm having a hard + + align:start position:0% +Basically, I well, I'm having a hard + + + align:start position:0% +Basically, I well, I'm having a hard +time believing that we can say how like + + align:start position:0% +time believing that we can say how like + + + align:start position:0% +time believing that we can say how like +whether creativity is democratic in + + align:start position:0% +whether creativity is democratic in + + + align:start position:0% +whether creativity is democratic in +distribution or whether it has some, you + + align:start position:0% +distribution or whether it has some, you + + + align:start position:0% +distribution or whether it has some, you +know, elite or or uh, you know, nonflat + + align:start position:0% +know, elite or or uh, you know, nonflat + + + align:start position:0% +know, elite or or uh, you know, nonflat +distribution to it on any rational basis + + align:start position:0% +distribution to it on any rational basis + + + align:start position:0% +distribution to it on any rational basis +because + + align:start position:0% +because + + + align:start position:0% +because +so much of our discussion of what + + align:start position:0% +so much of our discussion of what + + + align:start position:0% +so much of our discussion of what +creativity is and how we value it is not + + align:start position:0% +creativity is and how we value it is not + + + align:start position:0% +creativity is and how we value it is not +rational. So + + align:start position:0% +rational. So + + + align:start position:0% +rational. So +there there's there's something else + + align:start position:0% +there there's there's something else + + + align:start position:0% +there there's there's something else +going on here than that that needs to be + + align:start position:0% +going on here than that that needs to be + + + align:start position:0% +going on here than that that needs to be +discussed if we're going to try and say + + align:start position:0% +discussed if we're going to try and say + + + align:start position:0% +discussed if we're going to try and say +that geniuses are qualitatively + + align:start position:0% +that geniuses are qualitatively + + + align:start position:0% +that geniuses are qualitatively +different than average. + + align:start position:0% +different than average. + + + align:start position:0% +different than average. +One thing you can say which the all of + + align:start position:0% +One thing you can say which the all of + + + align:start position:0% +One thing you can say which the all of +the + + align:start position:0% +the + + + align:start position:0% +the +totalitarian countries have capitalized + + align:start position:0% +totalitarian countries have capitalized + + + align:start position:0% +totalitarian countries have capitalized +on is that if you sort of regiment large + + align:start position:0% +on is that if you sort of regiment large + + + align:start position:0% +on is that if you sort of regiment large +enough members of the population + + align:start position:0% +enough members of the population + + + align:start position:0% +enough members of the population +to be + + align:start position:0% +to be + + + align:start position:0% +to be +pole vaultters or athletes or musicians + + align:start position:0% +pole vaultters or athletes or musicians + + + align:start position:0% +pole vaultters or athletes or musicians +or anything + + align:start position:0% +or anything + + + align:start position:0% +or anything +you're going out of that there will come + + align:start position:0% +you're going out of that there will come + + + align:start position:0% +you're going out of that there will come +a few geniuses who would otherwise not + + align:start position:0% +a few geniuses who would otherwise not + + + align:start position:0% +a few geniuses who would otherwise not +have been noticed. + + align:start position:0% +have been noticed. + + + align:start position:0% +have been noticed. +I mean that that was the reason why the + + align:start position:0% +I mean that that was the reason why the + + + align:start position:0% +I mean that that was the reason why the +Soviet Union continued for 70 years. + + align:start position:0% +Soviet Union continued for 70 years. + + + align:start position:0% +Soviet Union continued for 70 years. +Everybody I as I mentioned knew it was a + + align:start position:0% +Everybody I as I mentioned knew it was a + + + align:start position:0% +Everybody I as I mentioned knew it was a +a bad system that it wouldn't work but + + align:start position:0% +a bad system that it wouldn't work but + + + align:start position:0% +a bad system that it wouldn't work but +um everybody wasn't equally encouraged + + align:start position:0% +um everybody wasn't equally encouraged + + + align:start position:0% +um everybody wasn't equally encouraged +and so they had these masses of young + + align:start position:0% +and so they had these masses of young + + + align:start position:0% +and so they had these masses of young +people marching together and doing + + align:start position:0% +people marching together and doing + + + align:start position:0% +people marching together and doing +athletics together and a few of them + + align:start position:0% +athletics together and a few of them + + + align:start position:0% +athletics together and a few of them +really were geniuses and that seemed to + + align:start position:0% +really were geniuses and that seemed to + + + align:start position:0% +really were geniuses and that seemed to +compensate for all the failures of the + + align:start position:0% +compensate for all the failures of the + + + align:start position:0% +compensate for all the failures of the +system. In our in democratic worlds, + + align:start position:0% +system. In our in democratic worlds, + + + align:start position:0% +system. In our in democratic worlds, +things are less well organized. But the + + align:start position:0% +things are less well organized. But the + + + align:start position:0% +things are less well organized. But the +fact remains that um it isn't just a + + align:start position:0% +fact remains that um it isn't just a + + + align:start position:0% +fact remains that um it isn't just a +question of nurturing and it isn't some + + align:start position:0% +question of nurturing and it isn't some + + + align:start position:0% +question of nurturing and it isn't some +innate ability that we know about. But + + align:start position:0% +innate ability that we know about. But + + + align:start position:0% +innate ability that we know about. But +you know, + + align:start position:0% +you know, + + + align:start position:0% +you know, +just encouraging people think they're + + align:start position:0% +just encouraging people think they're + + + align:start position:0% +just encouraging people think they're +all creative doesn't make them all + + align:start position:0% +all creative doesn't make them all + + + align:start position:0% +all creative doesn't make them all +creative. only there's still going to be + + align:start position:0% +creative. only there's still going to be + + + align:start position:0% +creative. only there's still going to be +that handful who really stand out + + align:start position:0% +that handful who really stand out + + + align:start position:0% +that handful who really stand out +and those are the geniuses and or near + + align:start position:0% +and those are the geniuses and or near + + + align:start position:0% +and those are the geniuses and or near +geniuses and the question is how to + + align:start position:0% +geniuses and the question is how to + + + align:start position:0% +geniuses and the question is how to +explain them + + align:start position:0% +explain them + + + align:start position:0% +explain them +but maybe you'll do that in the paper I + + align:start position:0% +but maybe you'll do that in the paper I + + + align:start position:0% +but maybe you'll do that in the paper I +don't know + + align:start position:0% + + + + align:start position:0% + +you you can and can any of us help + + align:start position:0% +you you can and can any of us help + + + align:start position:0% +you you can and can any of us help +Harold no Harold go ahead uh I was + + align:start position:0% +Harold no Harold go ahead uh I was + + + align:start position:0% +Harold no Harold go ahead uh I was +wondering how you deal with the cases of + + align:start position:0% +wondering how you deal with the cases of + + + align:start position:0% +wondering how you deal with the cases of +like like autistic sants. Yeah, I was + + align:start position:0% +like like autistic sants. Yeah, I was + + + align:start position:0% +like like autistic sants. Yeah, I was +actually just researching him today. + + align:start position:0% +actually just researching him today. + + + align:start position:0% +actually just researching him today. +Haven't really dived into that just yet. + + align:start position:0% +Haven't really dived into that just yet. + + + align:start position:0% +Haven't really dived into that just yet. +So, that's definitely to be considered. + + align:start position:0% +So, that's definitely to be considered. + + + align:start position:0% +So, that's definitely to be considered. +I really don't know what to think of + + align:start position:0% +I really don't know what to think of + + + align:start position:0% +I really don't know what to think of +that just yet. Yeah, because my mom's a + + align:start position:0% +that just yet. Yeah, because my mom's a + + + align:start position:0% +that just yet. Yeah, because my mom's a +neurologist and she's worked with kids + + align:start position:0% +neurologist and she's worked with kids + + + align:start position:0% +neurologist and she's worked with kids +who are, you know, you can't communicate + + align:start position:0% +who are, you know, you can't communicate + + + align:start position:0% +who are, you know, you can't communicate +with them, but they could, you know, + + align:start position:0% +with them, but they could, you know, + + + align:start position:0% +with them, but they could, you know, +draw these amazing paintings and, you + + align:start position:0% +draw these amazing paintings and, you + + + align:start position:0% +draw these amazing paintings and, you +know, do all this, you know, perform + + align:start position:0% +know, do all this, you know, perform + + + align:start position:0% +know, do all this, you know, perform +great pieces. I'm not sure they can. + + align:start position:0% +great pieces. I'm not sure they can. + + + align:start position:0% +great pieces. I'm not sure they can. +Actually, I think they do construct + + align:start position:0% +Actually, I think they do construct + + + align:start position:0% +Actually, I think they do construct +their own pieces. Some of them do. So, + + align:start position:0% +their own pieces. Some of them do. So, + + + align:start position:0% +their own pieces. Some of them do. So, +that is creative. Like playing someone + + align:start position:0% +that is creative. Like playing someone + + + align:start position:0% +that is creative. Like playing someone +else's piece may not be considered + + align:start position:0% +else's piece may not be considered + + + align:start position:0% +else's piece may not be considered +creative, but I mean it depends + + align:start position:0% +creative, but I mean it depends + + + align:start position:0% +creative, but I mean it depends +how where you're going with the argument + + align:start position:0% +how where you're going with the argument + + + align:start position:0% +how where you're going with the argument +in your paper. Another + + align:start position:0% + + + + align:start position:0% + +just quick question is your argument + + align:start position:0% +just quick question is your argument + + + align:start position:0% +just quick question is your argument +that there's sort of a Gaussian + + align:start position:0% +that there's sort of a Gaussian + + + align:start position:0% +that there's sort of a Gaussian +distribution and everything in the + + align:start position:0% +distribution and everything in the + + + align:start position:0% +distribution and everything in the +middle is kind of interchangeable and + + align:start position:0% +middle is kind of interchangeable and + + + align:start position:0% +middle is kind of interchangeable and +then once you get out like say two + + align:start position:0% +then once you get out like say two + + + align:start position:0% +then once you get out like say two +standard deviations it's this weird + + align:start position:0% +standard deviations it's this weird + + + align:start position:0% +standard deviations it's this weird +conflicting point or is it that like you + + align:start position:0% +conflicting point or is it that like you + + + align:start position:0% +conflicting point or is it that like you +know basically there's every most people + + align:start position:0% +know basically there's every most people + + + align:start position:0% +know basically there's every most people +are in the middle and there's a little + + align:start position:0% +are in the middle and there's a little + + + align:start position:0% +are in the middle and there's a little +spike out at one end and a little spike + + align:start position:0% +spike out at one end and a little spike + + + align:start position:0% +spike out at one end and a little spike +out at that end and there's nothing + + align:start position:0% +out at that end and there's nothing + + + align:start position:0% +out at that end and there's nothing +really in between more of a Gian + + align:start position:0% +really in between more of a Gian + + + align:start position:0% +really in between more of a Gian +distribution + + align:start position:0% + + + + align:start position:0% + +of course I mean that was the whole + + align:start position:0% +of course I mean that was the whole + + + align:start position:0% +of course I mean that was the whole +thing I was sort of trying to undermine + + align:start position:0% +thing I was sort of trying to undermine + + + align:start position:0% +thing I was sort of trying to undermine +but that that you can even put it in a + + align:start position:0% +but that that you can even put it in a + + + align:start position:0% +but that that you can even put it in a +distribution. Uh I don't see why that + + align:start position:0% +distribution. Uh I don't see why that + + + align:start position:0% +distribution. Uh I don't see why that +though. I don't see how. So if you have + + align:start position:0% +though. I don't see how. So if you have + + + align:start position:0% +though. I don't see how. So if you have +a Gaussian distribution then + + align:start position:0% +a Gaussian distribution then + + + align:start position:0% +a Gaussian distribution then +and you want it to mean something then + + align:start position:0% +and you want it to mean something then + + + align:start position:0% +and you want it to mean something then +you need to have some uh objective + + align:start position:0% +you need to have some uh objective + + + align:start position:0% +you need to have some uh objective +meaning attached to the variable that + + align:start position:0% +meaning attached to the variable that + + + align:start position:0% +meaning attached to the variable that +your distribution is over. + + align:start position:0% +your distribution is over. + + + align:start position:0% +your distribution is over. +Otherwise I mean then then it might mean + + align:start position:0% +Otherwise I mean then then it might mean + + + align:start position:0% +Otherwise I mean then then it might mean +something to you because it's subjective + + align:start position:0% +something to you because it's subjective + + + align:start position:0% +something to you because it's subjective +you know and say well this is how + + align:start position:0% +you know and say well this is how + + + align:start position:0% +you know and say well this is how +creative people are. but it's not going + + align:start position:0% +creative people are. but it's not going + + + align:start position:0% +creative people are. but it's not going +to mean much to everybody else because + + align:start position:0% +to mean much to everybody else because + + + align:start position:0% +to mean much to everybody else because +they don't know they can't hold your + + align:start position:0% +they don't know they can't hold your + + + align:start position:0% +they don't know they can't hold your +meaning of creativity. So that that + + align:start position:0% +meaning of creativity. So that that + + + align:start position:0% +meaning of creativity. So that that +that's what I think the challenge I + + align:start position:0% +that's what I think the challenge I + + + align:start position:0% +that's what I think the challenge I +would pose is well I think I don't know + + align:start position:0% +would pose is well I think I don't know + + + align:start position:0% +would pose is well I think I don't know +if I made this clear or not but when I + + align:start position:0% +if I made this clear or not but when I + + + align:start position:0% +if I made this clear or not but when I +say people are creative I I mean that in + + align:start position:0% +say people are creative I I mean that in + + + align:start position:0% +say people are creative I I mean that in +a sense we are all creative like we had + + align:start position:0% +a sense we are all creative like we had + + + align:start position:0% +a sense we are all creative like we had +to be creative in order to get where we + + align:start position:0% +to be creative in order to get where we + + + align:start position:0% +to be creative in order to get where we +are today. in order when we experience a + + align:start position:0% +are today. in order when we experience a + + + align:start position:0% +are today. in order when we experience a +new concept or when we experience an + + align:start position:0% +new concept or when we experience an + + + align:start position:0% +new concept or when we experience an +event in the world, we must create a + + align:start position:0% +event in the world, we must create a + + + align:start position:0% +event in the world, we must create a +concept that makes sense of that + + align:start position:0% +concept that makes sense of that + + + align:start position:0% +concept that makes sense of that +experience. And that's that's what I'm + + align:start position:0% +experience. And that's that's what I'm + + + align:start position:0% +experience. And that's that's what I'm +saying. In that sense, we are all + + align:start position:0% +saying. In that sense, we are all + + + align:start position:0% +saying. In that sense, we are all +creative. But then there are these + + align:start position:0% +creative. But then there are these + + + align:start position:0% +creative. But then there are these +anomalies, those two standard deviations + + align:start position:0% +anomalies, those two standard deviations + + + align:start position:0% +anomalies, those two standard deviations +to the right or left where this ability + + align:start position:0% +to the right or left where this ability + + + align:start position:0% +to the right or left where this ability +seems to be overdeveloped, either + + align:start position:0% +seems to be overdeveloped, either + + + align:start position:0% +seems to be overdeveloped, either +overdeveloped or + + align:start position:0% + + + + align:start position:0% + +overdeveloped, underdeveloped. That's by + + align:start position:0% +overdeveloped, underdeveloped. That's by + + + align:start position:0% +overdeveloped, underdeveloped. That's by +the nurture or by nature. Genetically, + + align:start position:0% +the nurture or by nature. Genetically, + + + align:start position:0% +the nurture or by nature. Genetically, +they just have this ability that's far + + align:start position:0% +they just have this ability that's far + + + align:start position:0% +they just have this ability that's far +that is far superior than that of the + + align:start position:0% +that is far superior than that of the + + + align:start position:0% +that is far superior than that of the +average person. + + align:start position:0% +average person. + + + align:start position:0% +average person. +at at the Pikau inaugural there was some + + align:start position:0% +at at the Pikau inaugural there was some + + + align:start position:0% +at at the Pikau inaugural there was some +discussion about nature and nurture that + + align:start position:0% +discussion about nature and nurture that + + + align:start position:0% +discussion about nature and nurture that +came from questions from the floor and + + align:start position:0% +came from questions from the floor and + + + align:start position:0% +came from questions from the floor and +um in the panel of the five Nobel + + align:start position:0% +um in the panel of the five Nobel + + + align:start position:0% +um in the panel of the five Nobel +laureates they all agreed that that's + + align:start position:0% +laureates they all agreed that that's + + + align:start position:0% +laureates they all agreed that that's +not an interesting scientific question + + align:start position:0% +not an interesting scientific question + + + align:start position:0% +not an interesting scientific question +anymore before people used to think in + + align:start position:0% +anymore before people used to think in + + + align:start position:0% +anymore before people used to think in +terms of these alternatives but what + + align:start position:0% +terms of these alternatives but what + + + align:start position:0% +terms of these alternatives but what +we've learned is that it's all a + + align:start position:0% +we've learned is that it's all a + + + align:start position:0% +we've learned is that it's all a +combination of both. Mhm. I don't know + + align:start position:0% +combination of both. Mhm. I don't know + + + align:start position:0% +combination of both. Mhm. I don't know +if that's of any help to you. Yeah, + + align:start position:0% +if that's of any help to you. Yeah, + + + align:start position:0% +if that's of any help to you. Yeah, +that's what I'm going to go into. It's + + align:start position:0% +that's what I'm going to go into. It's + + + align:start position:0% +that's what I'm going to go into. It's +com definitely a combination of both. + + align:start position:0% +com definitely a combination of both. + + + align:start position:0% +com definitely a combination of both. +All right. So, the if that's true, then + + align:start position:0% +All right. So, the if that's true, then + + + align:start position:0% +All right. So, the if that's true, then +what the job for the creative thinker in + + align:start position:0% +what the job for the creative thinker in + + + align:start position:0% +what the job for the creative thinker in +science and about the life in general + + align:start position:0% +science and about the life in general + + + align:start position:0% +science and about the life in general +would be just how do the two enter in? + + align:start position:0% +would be just how do the two enter in? + + + align:start position:0% +would be just how do the two enter in? +Just how in clear cases does one find + + align:start position:0% +Just how in clear cases does one find + + + align:start position:0% +Just how in clear cases does one find +the effect of both of them? and they're + + align:start position:0% +the effect of both of them? and they're + + + align:start position:0% +the effect of both of them? and they're +responding to each other in some kind of + + align:start position:0% +responding to each other in some kind of + + + align:start position:0% +responding to each other in some kind of +ricochet. I think that would be very + + align:start position:0% +ricochet. I think that would be very + + + align:start position:0% +ricochet. I think that would be very +useful in writing your papers on I think + + align:start position:0% +useful in writing your papers on I think + + + align:start position:0% +useful in writing your papers on I think +in philosophy in general but in + + align:start position:0% +in philosophy in general but in + + + align:start position:0% +in philosophy in general but in +something as obscure as the topic of + + align:start position:0% +something as obscure as the topic of + + + align:start position:0% +something as obscure as the topic of +this course. + + align:start position:0% +this course. + + + align:start position:0% +this course. +try very very hard to focus on + + align:start position:0% +try very very hard to focus on + + + align:start position:0% +try very very hard to focus on +clear cases and analyze them in terms of + + align:start position:0% +clear cases and analyze them in terms of + + + align:start position:0% +clear cases and analyze them in terms of +something details that you can clarify + + align:start position:0% +something details that you can clarify + + + align:start position:0% +something details that you can clarify +rather than feeling any need to create a + + align:start position:0% +rather than feeling any need to create a + + + align:start position:0% +rather than feeling any need to create a +grand new metaphysics of any sort or + + align:start position:0% +grand new metaphysics of any sort or + + + align:start position:0% +grand new metaphysics of any sort or +even uh a solution to whatever problem + + align:start position:0% +even uh a solution to whatever problem + + + align:start position:0% +even uh a solution to whatever problem +you're concerned about. It's the + + align:start position:0% +you're concerned about. It's the + + + align:start position:0% +you're concerned about. It's the +analysis. It's the focusing upon details + + align:start position:0% +analysis. It's the focusing upon details + + + align:start position:0% +analysis. It's the focusing upon details +within a complicated system as a way of + + align:start position:0% +within a complicated system as a way of + + + align:start position:0% +within a complicated system as a way of +revealing their importance for each + + align:start position:0% +revealing their importance for each + + + align:start position:0% +revealing their importance for each +other. That that I think is crucial. Um + + align:start position:0% +other. That that I think is crucial. Um + + + align:start position:0% +other. That that I think is crucial. Um +I say that for this paper because that's + + align:start position:0% +I say that for this paper because that's + + + align:start position:0% +I say that for this paper because that's +what's hardest for people at at the + + align:start position:0% +what's hardest for people at at the + + + align:start position:0% +what's hardest for people at at the +beginning of their philosophical + + align:start position:0% +beginning of their philosophical + + + align:start position:0% +beginning of their philosophical +training to realize that that's really + + align:start position:0% +training to realize that that's really + + + align:start position:0% +training to realize that that's really +what matters. + + align:start position:0% +what matters. + + + align:start position:0% +what matters. +But as a matter of fact, I I myself + + align:start position:0% +But as a matter of fact, I I myself + + + align:start position:0% +But as a matter of fact, I I myself +believe that for me at least that's the + + align:start position:0% +believe that for me at least that's the + + + align:start position:0% +believe that for me at least that's the +best way to do philosophy. It's the only + + align:start position:0% +best way to do philosophy. It's the only + + + align:start position:0% +best way to do philosophy. It's the only +way I can do philosophy. Otherwise, uh I + + align:start position:0% +way I can do philosophy. Otherwise, uh I + + + align:start position:0% +way I can do philosophy. Otherwise, uh I +find that the generalizations and or + + align:start position:0% +find that the generalizations and or + + + align:start position:0% +find that the generalizations and or +platitudes and that I'm not creative. If + + align:start position:0% +platitudes and that I'm not creative. If + + + align:start position:0% +platitudes and that I'm not creative. If +I have any creativity myself, it's by + + align:start position:0% +I have any creativity myself, it's by + + + align:start position:0% +I have any creativity myself, it's by +having perceptions that other people + + align:start position:0% +having perceptions that other people + + + align:start position:0% +having perceptions that other people +don't. and then the ability to reveal + + align:start position:0% +don't. and then the ability to reveal + + + align:start position:0% +don't. and then the ability to reveal +the content of those perceptions and + + align:start position:0% +the content of those perceptions and + + + align:start position:0% +the content of those perceptions and +show how they're relevant to to whatever + + align:start position:0% +show how they're relevant to to whatever + + + align:start position:0% +show how they're relevant to to whatever +it is I'm trying to explain. Um, but it + + align:start position:0% +it is I'm trying to explain. Um, but it + + + align:start position:0% +it is I'm trying to explain. Um, but it +doesn't matter about me. I think that's + + align:start position:0% +doesn't matter about me. I think that's + + + align:start position:0% +doesn't matter about me. I think that's +advice I'd offer to all of you for the + + align:start position:0% +advice I'd offer to all of you for the + + + align:start position:0% +advice I'd offer to all of you for the +writing of papers. + + align:start position:0% +writing of papers. + + + align:start position:0% +writing of papers. +Thomas, um, okay. So um I was initially + + align:start position:0% +Thomas, um, okay. So um I was initially + + + align:start position:0% +Thomas, um, okay. So um I was initially +going to write on the necessity of + + align:start position:0% +going to write on the necessity of + + + align:start position:0% +going to write on the necessity of +creativity but um when I was doing my + + align:start position:0% +creativity but um when I was doing my + + + align:start position:0% +creativity but um when I was doing my +research I couldn't really find anything + + align:start position:0% +research I couldn't really find anything + + + align:start position:0% +research I couldn't really find anything +on it. I actually switched to creativity + + align:start position:0% +on it. I actually switched to creativity + + + align:start position:0% +on it. I actually switched to creativity +versus intelligence. Um and I also used + + align:start position:0% +versus intelligence. Um and I also used + + + align:start position:0% +versus intelligence. Um and I also used +a lot of Sternberg's work. Um and + + align:start position:0% +a lot of Sternberg's work. Um and + + + align:start position:0% +a lot of Sternberg's work. Um and +basically what I'm going to look at is + + align:start position:0% +basically what I'm going to look at is + + + align:start position:0% +basically what I'm going to look at is +um looking at kind of the definitions of + + align:start position:0% +um looking at kind of the definitions of + + + align:start position:0% +um looking at kind of the definitions of +creativity and intelligence and see + + align:start position:0% +creativity and intelligence and see + + + align:start position:0% +creativity and intelligence and see +whether you can actually have one + + align:start position:0% +whether you can actually have one + + + align:start position:0% +whether you can actually have one +without the other. say can you be + + align:start position:0% +without the other. say can you be + + + align:start position:0% +without the other. say can you be +creative but not necessarily always + + align:start position:0% +creative but not necessarily always + + + align:start position:0% +creative but not necessarily always +deemed to be as intelligent by like say + + align:start position:0% +deemed to be as intelligent by like say + + + align:start position:0% +deemed to be as intelligent by like say +the standard tests or whatever. Um or um + + align:start position:0% +the standard tests or whatever. Um or um + + + align:start position:0% +the standard tests or whatever. Um or um +what I found is that a lot of people + + align:start position:0% +what I found is that a lot of people + + + align:start position:0% +what I found is that a lot of people +argue that creativity is actually a + + align:start position:0% +argue that creativity is actually a + + + align:start position:0% +argue that creativity is actually a +subset of intelligence and that or + + align:start position:0% +subset of intelligence and that or + + + align:start position:0% +subset of intelligence and that or +actually what a subset of intelligence + + align:start position:0% +actually what a subset of intelligence + + + align:start position:0% +actually what a subset of intelligence +and that without intelligence you can't + + align:start position:0% +and that without intelligence you can't + + + align:start position:0% +and that without intelligence you can't +have creativity. How much intelligence? + + align:start position:0% +have creativity. How much intelligence? + + + align:start position:0% +have creativity. How much intelligence? +Well see that's thing it's what kind of + + align:start position:0% +Well see that's thing it's what kind of + + + align:start position:0% +Well see that's thing it's what kind of +intelligence are you talking about? So + + align:start position:0% +intelligence are you talking about? So + + + align:start position:0% +intelligence are you talking about? So +are you talking about the kind of + + align:start position:0% +are you talking about the kind of + + + align:start position:0% +are you talking about the kind of +intelligence which is proven by your + + align:start position:0% +intelligence which is proven by your + + + align:start position:0% +intelligence which is proven by your +standards IQ test. So um someone is seen + + align:start position:0% +standards IQ test. So um someone is seen + + + align:start position:0% +standards IQ test. So um someone is seen +to be or deemed to be intelligent + + align:start position:0% +to be or deemed to be intelligent + + + align:start position:0% +to be or deemed to be intelligent +because they're able to pass XY Z like + + align:start position:0% +because they're able to pass XY Z like + + + align:start position:0% +because they're able to pass XY Z like +with amazingly good results compared to + + align:start position:0% +with amazingly good results compared to + + + align:start position:0% +with amazingly good results compared to +the average person or um something which + + align:start position:0% +the average person or um something which + + + align:start position:0% +the average person or um something which +I think has cropped up once or twice in + + align:start position:0% +I think has cropped up once or twice in + + + align:start position:0% +I think has cropped up once or twice in +class is um what we call your everyday + + align:start position:0% +class is um what we call your everyday + + + align:start position:0% +class is um what we call your everyday +common sense. And is that more + + align:start position:0% +common sense. And is that more + + + align:start position:0% +common sense. And is that more +intelligent because you're taking a + + align:start position:0% +intelligent because you're taking a + + + align:start position:0% +intelligent because you're taking a +problem and you're you're seeing like + + align:start position:0% +problem and you're you're seeing like + + + align:start position:0% +problem and you're you're seeing like +you know, you're looking in a in a + + align:start position:0% +you know, you're looking in a in a + + + align:start position:0% +you know, you're looking in a in a +practical way and actually being able to + + align:start position:0% +practical way and actually being able to + + + align:start position:0% +practical way and actually being able to +solve it. And that is uh but that isn't + + align:start position:0% +solve it. And that is uh but that isn't + + + align:start position:0% +solve it. And that is uh but that isn't +prerequisite for all creativity. + + align:start position:0% +prerequisite for all creativity. + + + align:start position:0% +prerequisite for all creativity. +Well, maybe excuse me, what maybe or + + align:start position:0% +Well, maybe excuse me, what maybe or + + + align:start position:0% +Well, maybe excuse me, what maybe or +maybe not. Like that's what I'm trying + + align:start position:0% +maybe not. Like that's what I'm trying + + + align:start position:0% +maybe not. Like that's what I'm trying +to decide because very often the people + + align:start position:0% +to decide because very often the people + + + align:start position:0% +to decide because very often the people +we think of as creative, particularly + + align:start position:0% +we think of as creative, particularly + + + align:start position:0% +we think of as creative, particularly +the geniuses, don't have good common + + align:start position:0% +the geniuses, don't have good common + + + align:start position:0% +the geniuses, don't have good common +sense. Exactly. But because they don't + + align:start position:0% +sense. Exactly. But because they don't + + + align:start position:0% +sense. Exactly. But because they don't +live in that domain, it doesn't matter + + align:start position:0% +live in that domain, it doesn't matter + + + align:start position:0% +live in that domain, it doesn't matter +to them. Yeah. But then is it can you + + align:start position:0% +to them. Yeah. But then is it can you + + + align:start position:0% +to them. Yeah. But then is it can you +actually say then that they're really + + align:start position:0% +actually say then that they're really + + + align:start position:0% +actually say then that they're really +that intelligent because okay so a story + + align:start position:0% +that intelligent because okay so a story + + + align:start position:0% +that intelligent because okay so a story +for if for their for their purposes they + + align:start position:0% +for if for their for their purposes they + + + align:start position:0% +for if for their for their purposes they +don't they might not be as good but like + + align:start position:0% +don't they might not be as good but like + + + align:start position:0% +don't they might not be as good but like +okay so a a story Sternberg and Lubbert + + align:start position:0% +okay so a a story Sternberg and Lubbert + + + align:start position:0% +okay so a a story Sternberg and Lubbert +I think in a book which they both wrote + + align:start position:0% +I think in a book which they both wrote + + + align:start position:0% +I think in a book which they both wrote +together called define the crowd um they + + align:start position:0% +together called define the crowd um they + + + align:start position:0% +together called define the crowd um they +talk about um these two boys and they're + + align:start position:0% +talk about um these two boys and they're + + + align:start position:0% +talk about um these two boys and they're +in the they're in the woods + + align:start position:0% +in the they're in the woods + + + align:start position:0% +in the they're in the woods +and um there's this bear that's running + + align:start position:0% +and um there's this bear that's running + + + align:start position:0% +and um there's this bear that's running +after them. And then he says, "Well, to + + align:start position:0% +after them. And then he says, "Well, to + + + align:start position:0% +after them. And then he says, "Well, to +make this story to make more sense, you + + align:start position:0% +make this story to make more sense, you + + + align:start position:0% +make this story to make more sense, you +need to understand the background of + + align:start position:0% +need to understand the background of + + + align:start position:0% +need to understand the background of +these two boys." Now, one of these boys + + align:start position:0% +these two boys." Now, one of these boys + + + align:start position:0% +these two boys." Now, one of these boys +is really, really intelligent. Like he's + + align:start position:0% +is really, really intelligent. Like he's + + + align:start position:0% +is really, really intelligent. Like he's +got really high marks and all his like + + align:start position:0% +got really high marks and all his like + + + align:start position:0% +got really high marks and all his like +IQ tests. He's got really good + + align:start position:0% +IQ tests. He's got really good + + + align:start position:0% +IQ tests. He's got really good +commendations from teachers and his + + align:start position:0% +commendations from teachers and his + + + align:start position:0% +commendations from teachers and his +parents think he's intelligent and like + + align:start position:0% +parents think he's intelligent and like + + + align:start position:0% +parents think he's intelligent and like +um with a lot of arrogance, he kind of + + align:start position:0% +um with a lot of arrogance, he kind of + + + align:start position:0% +um with a lot of arrogance, he kind of +says, "Well, and the boy pretty much + + align:start position:0% +says, "Well, and the boy pretty much + + + align:start position:0% +says, "Well, and the boy pretty much +thinks he's pretty intelligent, too." + + align:start position:0% +thinks he's pretty intelligent, too." + + + align:start position:0% +thinks he's pretty intelligent, too." +Um, but then there's this other kid + + align:start position:0% +Um, but then there's this other kid + + + align:start position:0% +Um, but then there's this other kid +there and he doesn't have such good + + align:start position:0% +there and he doesn't have such good + + + align:start position:0% +there and he doesn't have such good +grades or whatever. And um, he doesn't + + align:start position:0% +grades or whatever. And um, he doesn't + + + align:start position:0% +grades or whatever. And um, he doesn't +have as good commendations and he's not + + align:start position:0% +have as good commendations and he's not + + + align:start position:0% +have as good commendations and he's not +deemed to be as intelligent, but they're + + align:start position:0% +deemed to be as intelligent, but they're + + + align:start position:0% +deemed to be as intelligent, but they're +both in this in this wood um, in these + + align:start position:0% +both in this in this wood um, in these + + + align:start position:0% +both in this in this wood um, in these +woods and there's this grizzly bear + + align:start position:0% +woods and there's this grizzly bear + + + align:start position:0% +woods and there's this grizzly bear +really angry. He's running after them. + + align:start position:0% +really angry. He's running after them. + + + align:start position:0% +really angry. He's running after them. +And the intelligent boy is able to stand + + align:start position:0% +And the intelligent boy is able to stand + + + align:start position:0% +And the intelligent boy is able to stand +there and calculate the speed at which + + align:start position:0% +there and calculate the speed at which + + + align:start position:0% +there and calculate the speed at which +the bear is + + align:start position:0% +the bear is + + + align:start position:0% +the bear is +the speed at which like the bear is like + + align:start position:0% +the speed at which like the bear is like + + + align:start position:0% +the speed at which like the bear is like +running towards him and realizes there + + align:start position:0% +running towards him and realizes there + + + align:start position:0% +running towards him and realizes there +something like 17 seconds before the + + align:start position:0% +something like 17 seconds before the + + + align:start position:0% +something like 17 seconds before the +bear is going to get to them. But + + align:start position:0% +bear is going to get to them. But + + + align:start position:0% +bear is going to get to them. But +there's no way that they're going to be + + align:start position:0% +there's no way that they're going to be + + + align:start position:0% +there's no way that they're going to be +able to run away because there's too + + align:start position:0% +able to run away because there's too + + + align:start position:0% +able to run away because there's too +short a time for both of them to get + + align:start position:0% +short a time for both of them to get + + + align:start position:0% +short a time for both of them to get +away. And the story goes that the other + + align:start position:0% +away. And the story goes that the other + + + align:start position:0% +away. And the story goes that the other +boy in the meantime is busy changing + + align:start position:0% +boy in the meantime is busy changing + + + align:start position:0% +boy in the meantime is busy changing +from his hiking shoes to his jogging + + align:start position:0% +from his hiking shoes to his jogging + + + align:start position:0% +from his hiking shoes to his jogging +shoes. And the intelligent boy kind of + + align:start position:0% +shoes. And the intelligent boy kind of + + + align:start position:0% +shoes. And the intelligent boy kind of +looks at this like other guy and he's + + align:start position:0% +looks at this like other guy and he's + + + align:start position:0% +looks at this like other guy and he's +like, "What are you doing? We're never + + align:start position:0% +like, "What are you doing? We're never + + + align:start position:0% +like, "What are you doing? We're never +gonna get away." And the other guy says, + + align:start position:0% +gonna get away." And the other guy says, + + + align:start position:0% +gonna get away." And the other guy says, +"Well, yeah, but that doesn't really + + align:start position:0% +"Well, yeah, but that doesn't really + + + align:start position:0% +"Well, yeah, but that doesn't really +matter because all that matters is that + + align:start position:0% +matter because all that matters is that + + + align:start position:0% +matter because all that matters is that +um I get further away than you." + + align:start position:0% +um I get further away than you." + + + align:start position:0% +um I get further away than you." +So, is it really that this intelligent + + align:start position:0% +So, is it really that this intelligent + + + align:start position:0% +So, is it really that this intelligent +boy was really that intelligent? because + + align:start position:0% +boy was really that intelligent? because + + + align:start position:0% +boy was really that intelligent? because +he clearly can't have been that + + align:start position:0% +he clearly can't have been that + + + align:start position:0% +he clearly can't have been that +intelligent cuz maybe it would have been + + align:start position:0% +intelligent cuz maybe it would have been + + + align:start position:0% +intelligent cuz maybe it would have been +better instead of him sitting there and + + align:start position:0% +better instead of him sitting there and + + + align:start position:0% +better instead of him sitting there and +calculating the speed at which this bear + + align:start position:0% +calculating the speed at which this bear + + + align:start position:0% +calculating the speed at which this bear +was going to get to them if he thought + + align:start position:0% +was going to get to them if he thought + + + align:start position:0% +was going to get to them if he thought +of a better way of actually being able + + align:start position:0% +of a better way of actually being able + + + align:start position:0% +of a better way of actually being able +to get away. Um whereas obviously this + + align:start position:0% +to get away. Um whereas obviously this + + + align:start position:0% +to get away. Um whereas obviously this +so-called not so intelligent guy + + align:start position:0% +so-called not so intelligent guy + + + align:start position:0% +so-called not so intelligent guy +actually, you know, did manage to run to + + align:start position:0% +actually, you know, did manage to run to + + + align:start position:0% +actually, you know, did manage to run to +safety because the other guy got killed + + align:start position:0% +safety because the other guy got killed + + + align:start position:0% +safety because the other guy got killed +because the bear got him first. But do + + align:start position:0% +because the bear got him first. But do + + + align:start position:0% +because the bear got him first. But do +you see? So there is that kind of slight + + align:start position:0% +you see? So there is that kind of slight + + + align:start position:0% +you see? So there is that kind of slight +dis this kind of really blurry line + + align:start position:0% +dis this kind of really blurry line + + + align:start position:0% +dis this kind of really blurry line +between what you can say is like really + + align:start position:0% +between what you can say is like really + + + align:start position:0% +between what you can say is like really +intelligent or what is really creative + + align:start position:0% +intelligent or what is really creative + + + align:start position:0% +intelligent or what is really creative +because in that kind of situation you + + align:start position:0% +because in that kind of situation you + + + align:start position:0% +because in that kind of situation you +would say that the second boy the + + align:start position:0% +would say that the second boy the + + + align:start position:0% +would say that the second boy the +technically not so intelligent boy was + + align:start position:0% +technically not so intelligent boy was + + + align:start position:0% +technically not so intelligent boy was +actually far more intelligent or was it + + align:start position:0% +actually far more intelligent or was it + + + align:start position:0% +actually far more intelligent or was it +yeah so another thing that I've come up + + align:start position:0% +yeah so another thing that I've come up + + + align:start position:0% +yeah so another thing that I've come up +with so the first um so I've almost + + align:start position:0% +with so the first um so I've almost + + + align:start position:0% +with so the first um so I've almost +finished my paper but the the first + + align:start position:0% +finished my paper but the the first + + + align:start position:0% +finished my paper but the the first +thing I kind of set about doing which I + + align:start position:0% +thing I kind of set about doing which I + + + align:start position:0% +thing I kind of set about doing which I +don't think I did very well in my my + + align:start position:0% +don't think I did very well in my my + + + align:start position:0% +don't think I did very well in my my +first essay is to try and define + + align:start position:0% +first essay is to try and define + + + align:start position:0% +first essay is to try and define +creativity and try and define what is + + align:start position:0% +creativity and try and define what is + + + align:start position:0% +creativity and try and define what is +meant by intelligence. And I found like + + align:start position:0% +meant by intelligence. And I found like + + + align:start position:0% +meant by intelligence. And I found like +one or two models that other people have + + align:start position:0% +one or two models that other people have + + + align:start position:0% +one or two models that other people have +come up with and I discussed those a + + align:start position:0% +come up with and I discussed those a + + + align:start position:0% +come up with and I discussed those a +bit. Um, and something that's come up in + + align:start position:0% +bit. Um, and something that's come up in + + + align:start position:0% +bit. Um, and something that's come up in +the definition of what is considered + + align:start position:0% +the definition of what is considered + + + align:start position:0% +the definition of what is considered +creative is not that it's just novel, + + align:start position:0% +creative is not that it's just novel, + + + align:start position:0% +creative is not that it's just novel, +but like you said is whether it's + + align:start position:0% +but like you said is whether it's + + + align:start position:0% +but like you said is whether it's +actually appropriate or not. Whether + + align:start position:0% +actually appropriate or not. Whether + + + align:start position:0% +actually appropriate or not. Whether +it's what appropriate appropriate. So um + + align:start position:0% +it's what appropriate appropriate. So um + + + align:start position:0% +it's what appropriate appropriate. So um +something might be creative but just not + + align:start position:0% +something might be creative but just not + + + align:start position:0% +something might be creative but just not +deemed socially appropriate. And an + + align:start position:0% +deemed socially appropriate. And an + + + align:start position:0% +deemed socially appropriate. And an +example which Sternberg actually gives + + align:start position:0% +example which Sternberg actually gives + + + align:start position:0% +example which Sternberg actually gives +is um the artist Damian Hurst. I don't + + align:start position:0% +is um the artist Damian Hurst. I don't + + + align:start position:0% +is um the artist Damian Hurst. I don't +know if you guys have heard of him. He + + align:start position:0% +know if you guys have heard of him. He + + + align:start position:0% +know if you guys have heard of him. He +basically one of his pieces of art he um + + align:start position:0% +basically one of his pieces of art he um + + + align:start position:0% +basically one of his pieces of art he um +cut up animal um frag um cut up animals + + align:start position:0% +cut up animal um frag um cut up animals + + + align:start position:0% +cut up animal um frag um cut up animals +into fragments and put them on display + + align:start position:0% +into fragments and put them on display + + + align:start position:0% +into fragments and put them on display +and that's what he called art. And I + + align:start position:0% +and that's what he called art. And I + + + align:start position:0% +and that's what he called art. And I +mean it received a lot of criticism + + align:start position:0% +mean it received a lot of criticism + + + align:start position:0% +mean it received a lot of criticism +because a lot of people said well you + + align:start position:0% +because a lot of people said well you + + + align:start position:0% +because a lot of people said well you +know obviously that's not art that's + + align:start position:0% +know obviously that's not art that's + + + align:start position:0% +know obviously that's not art that's +just complete butchery. But can you not + + align:start position:0% +just complete butchery. But can you not + + + align:start position:0% +just complete butchery. But can you not +I mean you explain this to me. He he + + align:start position:0% +I mean you explain this to me. He he + + + align:start position:0% +I mean you explain this to me. He he +live he would kill animals and then + + align:start position:0% +live he would kill animals and then + + + align:start position:0% +live he would kill animals and then +rearrange the parts. He literally um + + align:start position:0% +rearrange the parts. He literally um + + + align:start position:0% +rearrange the parts. He literally um +like you would get them in like a + + align:start position:0% +like you would get them in like a + + + align:start position:0% +like you would get them in like a +slicing machine basically. You take you + + align:start position:0% +slicing machine basically. You take you + + + align:start position:0% +slicing machine basically. You take you +literally slice the Yeah, that guy he + + align:start position:0% +literally slice the Yeah, that guy he + + + align:start position:0% +literally slice the Yeah, that guy he +he's literally like sliced the animal + + align:start position:0% +he's literally like sliced the animal + + + align:start position:0% +he's literally like sliced the animal +into pieces and he didn't rearrange + + align:start position:0% +into pieces and he didn't rearrange + + + align:start position:0% +into pieces and he didn't rearrange +them, but he put these pieces in like + + align:start position:0% +them, but he put these pieces in like + + + align:start position:0% +them, but he put these pieces in like +preservatives and stuff and he put them + + align:start position:0% +preservatives and stuff and he put them + + + align:start position:0% +preservatives and stuff and he put them +in like double-sided glass um cabinets, + + align:start position:0% +in like double-sided glass um cabinets, + + + align:start position:0% +in like double-sided glass um cabinets, +whatever. So you can see like either + + align:start position:0% +whatever. So you can see like either + + + align:start position:0% +whatever. So you can see like either +side of basically like all the different + + align:start position:0% +side of basically like all the different + + + align:start position:0% +side of basically like all the different +organs and where they would be etc. + + align:start position:0% +organs and where they would be etc. + + + align:start position:0% +organs and where they would be etc. +Exactly as it would be in the live + + align:start position:0% +Exactly as it would be in the live + + + align:start position:0% +Exactly as it would be in the live +animal. And it was called art. But + + align:start position:0% +animal. And it was called art. But + + + align:start position:0% +animal. And it was called art. But +that's a that's exactly what people + + align:start position:0% +that's a that's exactly what people + + + align:start position:0% +that's a that's exactly what people +said. They said it was cruel, right? + + align:start position:0% +said. They said it was cruel, right? + + + align:start position:0% +said. They said it was cruel, right? +Because like + + align:start position:0% +Because like + + + align:start position:0% +Because like +well you can say it's cruel but it's I + + align:start position:0% +well you can say it's cruel but it's I + + + align:start position:0% +well you can say it's cruel but it's I +mean a lot of people said well is it + + align:start position:0% +mean a lot of people said well is it + + + align:start position:0% +mean a lot of people said well is it +complete butchery or whatever? And um I + + align:start position:0% +complete butchery or whatever? And um I + + + align:start position:0% +complete butchery or whatever? And um I +haven't heard of that. But if you um I + + align:start position:0% +haven't heard of that. But if you um I + + + align:start position:0% +haven't heard of that. But if you um I +think he was an English artist. + + align:start position:0% +think he was an English artist. + + + align:start position:0% +think he was an English artist. +No, this guy I'm sorry just to throw in + + align:start position:0% +No, this guy I'm sorry just to throw in + + + align:start position:0% +No, this guy I'm sorry just to throw in +one of an athlete had died and donated + + align:start position:0% +one of an athlete had died and donated + + + align:start position:0% +one of an athlete had died and donated +his body to him and h Damian H I guess I + + align:start position:0% +his body to him and h Damian H I guess I + + + align:start position:0% +his body to him and h Damian H I guess I +don't remember the names but what he did + + align:start position:0% +don't remember the names but what he did + + + align:start position:0% +don't remember the names but what he did +the um the artist guy skinned him + + align:start position:0% +the um the artist guy skinned him + + + align:start position:0% +the um the artist guy skinned him +skinned his body. I think he you said an + + align:start position:0% +skinned his body. I think he you said an + + + align:start position:0% +skinned his body. I think he you said an +athlete first. Yeah an athlete. He after + + align:start position:0% +athlete first. Yeah an athlete. He after + + + align:start position:0% +athlete first. Yeah an athlete. He after +he died he donated his body to the + + align:start position:0% +he died he donated his body to the + + + align:start position:0% +he died he donated his body to the +artist. Right. To the artist. The artist + + align:start position:0% +artist. Right. To the artist. The artist + + + align:start position:0% +artist. Right. To the artist. The artist +skinned his body and what he did is that + + align:start position:0% +skinned his body and what he did is that + + + align:start position:0% +skinned his body and what he did is that +he peeled back every all the muscles and + + align:start position:0% +he peeled back every all the muscles and + + + align:start position:0% +he peeled back every all the muscles and +like peeled like so you could see the + + align:start position:0% +like peeled like so you could see the + + + align:start position:0% +like peeled like so you could see the +different layers of muscles and then + + align:start position:0% +different layers of muscles and then + + + align:start position:0% +different layers of muscles and then +they put them on display where he's + + align:start position:0% +they put them on display where he's + + + align:start position:0% +they put them on display where he's +running like this but you can see all of + + align:start position:0% +running like this but you can see all of + + + align:start position:0% +running like this but you can see all of +his muscles peeled back and you can see + + align:start position:0% +his muscles peeled back and you can see + + + align:start position:0% +his muscles peeled back and you can see +all all the entire muscular structure of + + align:start position:0% +all all the entire muscular structure of + + + align:start position:0% +all all the entire muscular structure of +the body. That's um I actually thought + + align:start position:0% +the body. That's um I actually thought + + + align:start position:0% +the body. That's um I actually thought +that was pretty cool. That's another guy + + align:start position:0% +that was pretty cool. That's another guy + + + align:start position:0% +that was pretty cool. That's another guy +here and he displayed it. I mean that + + align:start position:0% +here and he displayed it. I mean that + + + align:start position:0% +here and he displayed it. I mean that +was that was his work of art + + align:start position:0% +was that was his work of art + + + align:start position:0% +was that was his work of art +becoming more popular. Yeah, it was + + align:start position:0% +becoming more popular. Yeah, it was + + + align:start position:0% +becoming more popular. Yeah, it was +called the I actually saw that + + align:start position:0% +called the I actually saw that + + + align:start position:0% +called the I actually saw that +exhibition. It was called Body Welds. + + align:start position:0% +exhibition. It was called Body Welds. + + + align:start position:0% +exhibition. It was called Body Welds. +Who was his name? Um Dr. Gunther + + align:start position:0% +Who was his name? Um Dr. Gunther + + + align:start position:0% +Who was his name? Um Dr. Gunther +Hunter I think or something like it's + + align:start position:0% +Hunter I think or something like it's + + + align:start position:0% +Hunter I think or something like it's +Gunther Body W. That was the name of the + + align:start position:0% +Gunther Body W. That was the name of the + + + align:start position:0% +Gunther Body W. That was the name of the +exhibition. It was really really + + align:start position:0% +exhibition. It was really really + + + align:start position:0% +exhibition. It was really really +popular. Um I don't know whether it was + + align:start position:0% +popular. Um I don't know whether it was + + + align:start position:0% +popular. Um I don't know whether it was +just popular in England but I think it + + align:start position:0% +just popular in England but I think it + + + align:start position:0% +just popular in England but I think it +went touring around Europe as well. He + + align:start position:0% +went touring around Europe as well. He + + + align:start position:0% +went touring around Europe as well. He +actually also did something really + + align:start position:0% +actually also did something really + + + align:start position:0% +actually also did something really +controversial. Yeah, that's the one. Um + + align:start position:0% +controversial. Yeah, that's the one. Um + + + align:start position:0% +controversial. Yeah, that's the one. Um +where he did a live um + + align:start position:0% +where he did a live um + + + align:start position:0% +where he did a live um +dissection of a human being um and it + + align:start position:0% +dissection of a human being um and it + + + align:start position:0% +dissection of a human being um and it +was all do you remember hearing that? + + align:start position:0% +was all do you remember hearing that? + + + align:start position:0% +was all do you remember hearing that? +Yeah. Come to the point. + + align:start position:0% +Yeah. Come to the point. + + + align:start position:0% +Yeah. Come to the point. +So again it's the idea of whether + + align:start position:0% +So again it's the idea of whether + + + align:start position:0% +So again it's the idea of whether +whether you can say admittedly it's not + + align:start position:0% +whether you can say admittedly it's not + + + align:start position:0% +whether you can say admittedly it's not +socially appropriate and but does that + + align:start position:0% +socially appropriate and but does that + + + align:start position:0% +socially appropriate and but does that +does that detract from it being + + align:start position:0% +does that detract from it being + + + align:start position:0% +does that detract from it being +creative? Because one of part of the + + align:start position:0% +creative? Because one of part of the + + + align:start position:0% +creative? Because one of part of the +definition of creative is that it's + + align:start position:0% +definition of creative is that it's + + + align:start position:0% +definition of creative is that it's +novel. So it's the use of maybe ordinary + + align:start position:0% +novel. So it's the use of maybe ordinary + + + align:start position:0% +novel. So it's the use of maybe ordinary +tools in a different way. So is that + + align:start position:0% +tools in a different way. So is that + + + align:start position:0% +tools in a different way. So is that +saying is it really fair to say + + align:start position:0% +saying is it really fair to say + + + align:start position:0% +saying is it really fair to say +objectively that what these people did + + align:start position:0% +objectively that what these people did + + + align:start position:0% +objectively that what these people did +is actually not created just because we + + align:start position:0% +is actually not created just because we + + + align:start position:0% +is actually not created just because we +deem it socially unacceptable + + align:start position:0% +deem it socially unacceptable + + + align:start position:0% +deem it socially unacceptable +do you see? So I mean there's that kind + + align:start position:0% +do you see? So I mean there's that kind + + + align:start position:0% +do you see? So I mean there's that kind +of fine I mean that's another bit of the + + align:start position:0% +of fine I mean that's another bit of the + + + align:start position:0% +of fine I mean that's another bit of the +discussion I go into when I go into kind + + align:start position:0% +discussion I go into when I go into kind + + + align:start position:0% +discussion I go into when I go into kind +of trying to define creativity and then + + align:start position:0% +of trying to define creativity and then + + + align:start position:0% +of trying to define creativity and then +the idea is basically I have the + + align:start position:0% +the idea is basically I have the + + + align:start position:0% +the idea is basically I have the +definition of creativity and like there + + align:start position:0% +definition of creativity and like there + + + align:start position:0% +definition of creativity and like there +are different models for intelligence + + align:start position:0% +are different models for intelligence + + + align:start position:0% +are different models for intelligence +and trying to see how interrelated the + + align:start position:0% +and trying to see how interrelated the + + + align:start position:0% +and trying to see how interrelated the +two are and whether you can have one + + align:start position:0% +two are and whether you can have one + + + align:start position:0% +two are and whether you can have one +without the other. Well I I would have + + align:start position:0% +without the other. Well I I would have + + + align:start position:0% +without the other. Well I I would have +thought in this case the socially + + align:start position:0% +thought in this case the socially + + + align:start position:0% +thought in this case the socially +inappropriate would be less important + + align:start position:0% +inappropriate would be less important + + + align:start position:0% +inappropriate would be less important +than the question of what he actually + + align:start position:0% +than the question of what he actually + + + align:start position:0% +than the question of what he actually +did with the material that he was + + align:start position:0% +did with the material that he was + + + align:start position:0% +did with the material that he was +presenting. uh artists, Michelangelo for + + align:start position:0% +presenting. uh artists, Michelangelo for + + + align:start position:0% +presenting. uh artists, Michelangelo for +instance, used to go um to study + + align:start position:0% +instance, used to go um to study + + + align:start position:0% +instance, used to go um to study +cadaavvers + + align:start position:0% +cadaavvers + + + align:start position:0% +cadaavvers +in order to learn about um the muscles + + align:start position:0% +in order to learn about um the muscles + + + align:start position:0% +in order to learn about um the muscles +and the structure of the of the anatomy. + + align:start position:0% +and the structure of the of the anatomy. + + + align:start position:0% +and the structure of the of the anatomy. +Um now, one might say uh that this + + align:start position:0% +Um now, one might say uh that this + + + align:start position:0% +Um now, one might say uh that this +artist was doing something comparable + + align:start position:0% +artist was doing something comparable + + + align:start position:0% +artist was doing something comparable +does doesn't yet prove to us how that + + align:start position:0% +does doesn't yet prove to us how that + + + align:start position:0% +does doesn't yet prove to us how that +he's very uh creative. He might have + + align:start position:0% +he's very uh creative. He might have + + + align:start position:0% +he's very uh creative. He might have +been a showman who was charging money + + align:start position:0% +been a showman who was charging money + + + align:start position:0% +been a showman who was charging money +and there's nothing creative unless + + align:start position:0% +and there's nothing creative unless + + + align:start position:0% +and there's nothing creative unless +there was a way in which he presented it + + align:start position:0% +there was a way in which he presented it + + + align:start position:0% +there was a way in which he presented it +under the circumstances of this being an + + align:start position:0% +under the circumstances of this being an + + + align:start position:0% +under the circumstances of this being an +art gallery or something like that that + + align:start position:0% +art gallery or something like that that + + + align:start position:0% +art gallery or something like that that +might make it creative. Yeah. So this + + align:start position:0% +might make it creative. Yeah. So this + + + align:start position:0% +might make it creative. Yeah. So this +this guy who did the body worlds + + align:start position:0% +this guy who did the body worlds + + + align:start position:0% +this guy who did the body worlds +exhibition um I mean it was very very + + align:start position:0% +exhibition um I mean it was very very + + + align:start position:0% +exhibition um I mean it was very very +controversial at the time but very + + align:start position:0% +controversial at the time but very + + + align:start position:0% +controversial at the time but very +popular like everyone was running to see + + align:start position:0% +popular like everyone was running to see + + + align:start position:0% +popular like everyone was running to see +it. Um, and he actually managed to get + + align:start position:0% +it. Um, and he actually managed to get + + + align:start position:0% +it. Um, and he actually managed to get +all the bodies he put on display because + + align:start position:0% +all the bodies he put on display because + + + align:start position:0% +all the bodies he put on display because +he um went through and got a grant and + + align:start position:0% +he um went through and got a grant and + + + align:start position:0% +he um went through and got a grant and +basically said he was trying to teach + + align:start position:0% +basically said he was trying to teach + + + align:start position:0% +basically said he was trying to teach +science. And the idea was is that + + align:start position:0% +science. And the idea was is that + + + align:start position:0% +science. And the idea was is that +basically he was putting out all this + + align:start position:0% +basically he was putting out all this + + + align:start position:0% +basically he was putting out all this +anatomy and he developed a very okay + + align:start position:0% +anatomy and he developed a very okay + + + align:start position:0% +anatomy and he developed a very okay +very interesting system where you could + + align:start position:0% +very interesting system where you could + + + align:start position:0% +very interesting system where you could +preserve um like body material using + + align:start position:0% +preserve um like body material using + + + align:start position:0% +preserve um like body material using +some sort of plastic which you can + + align:start position:0% +some sort of plastic which you can + + + align:start position:0% +some sort of plastic which you can +inject into material or whatever. So he + + align:start position:0% +inject into material or whatever. So he + + + align:start position:0% +inject into material or whatever. So he +had these really amazing displays where + + align:start position:0% +had these really amazing displays where + + + align:start position:0% +had these really amazing displays where +um he'd injected a a dye and it had gone + + align:start position:0% +um he'd injected a a dye and it had gone + + + align:start position:0% +um he'd injected a a dye and it had gone +into every single blood vessel and then + + align:start position:0% +into every single blood vessel and then + + + align:start position:0% +into every single blood vessel and then +dissolved away all the tissue, the bone, + + align:start position:0% +dissolved away all the tissue, the bone, + + + align:start position:0% +dissolved away all the tissue, the bone, +the muscle and everything. And all you + + align:start position:0% +the muscle and everything. And all you + + + align:start position:0% +the muscle and everything. And all you +had left standing was all the veins and + + align:start position:0% +had left standing was all the veins and + + + align:start position:0% +had left standing was all the veins and +arteries and everything and that's all + + align:start position:0% +arteries and everything and that's all + + + align:start position:0% +arteries and everything and that's all +you had. But you it was amazing. It was + + align:start position:0% +you had. But you it was amazing. It was + + + align:start position:0% +you had. But you it was amazing. It was +absolutely amazing. And that was what he + + align:start position:0% +absolutely amazing. And that was what he + + + align:start position:0% +absolutely amazing. And that was what he +put on display. But he was it wasn't + + align:start position:0% +put on display. But he was it wasn't + + + align:start position:0% +put on display. But he was it wasn't +supposed to be some sort of freak show + + align:start position:0% +supposed to be some sort of freak show + + + align:start position:0% +supposed to be some sort of freak show +which it really turned out to be. um or + + align:start position:0% +which it really turned out to be. um or + + + align:start position:0% +which it really turned out to be. um or +however I've perceived it, but it was + + align:start position:0% +however I've perceived it, but it was + + + align:start position:0% +however I've perceived it, but it was +supposed to kind of be a teaching a kind + + align:start position:0% +supposed to kind of be a teaching a kind + + + align:start position:0% +supposed to kind of be a teaching a kind +of science and art merging and teaching + + align:start position:0% +of science and art merging and teaching + + + align:start position:0% +of science and art merging and teaching +you about science and that kind of + + align:start position:0% +you about science and that kind of + + + align:start position:0% +you about science and that kind of +letting you see how everything's + + align:start position:0% +letting you see how everything's + + + align:start position:0% +letting you see how everything's +interrelated and that kind of thing. So, + + align:start position:0% +interrelated and that kind of thing. So, + + + align:start position:0% +interrelated and that kind of thing. So, +let me see if there's time + + align:start position:0% +let me see if there's time + + + align:start position:0% +let me see if there's time +for + + align:start position:0% +for + + + align:start position:0% +for +Harold and Megan. We never got to you. + + align:start position:0% +Harold and Megan. We never got to you. + + + align:start position:0% +Harold and Megan. We never got to you. +Can we stay a little longer? Not not + + align:start position:0% +Can we stay a little longer? Not not + + + align:start position:0% +Can we stay a little longer? Not not +much. Okay. Why don't Taz, do you mind + + align:start position:0% +much. Okay. Why don't Taz, do you mind + + + align:start position:0% +much. Okay. Why don't Taz, do you mind +if we move on? Nope. That's Harold. It's + + align:start position:0% +if we move on? Nope. That's Harold. It's + + + align:start position:0% +if we move on? Nope. That's Harold. It's +35. + + align:start position:0% +35. + + + align:start position:0% +35. +35 of five. That's 505. Five after. + + align:start position:0% +35 of five. That's 505. Five after. + + + align:start position:0% +35 of five. That's 505. Five after. +Yeah. Or 52. Five after. All right. Then + + align:start position:0% +Yeah. Or 52. Five after. All right. Then + + + align:start position:0% +Yeah. Or 52. Five after. All right. Then +why do And you've got to leave. Or are + + align:start position:0% +why do And you've got to leave. Or are + + + align:start position:0% +why do And you've got to leave. Or are +you thinking of the filming? No, no, no. + + align:start position:0% +you thinking of the filming? No, no, no. + + + align:start position:0% +you thinking of the filming? No, no, no. +I have to I may have to go in a little + + align:start position:0% +I have to I may have to go in a little + + + align:start position:0% +I have to I may have to go in a little +bit. No. Just tell me in 30 seconds what + + align:start position:0% +bit. No. Just tell me in 30 seconds what + + + align:start position:0% +bit. No. Just tell me in 30 seconds what +state your paper is in. Okay. I've been + + align:start position:0% +state your paper is in. Okay. I've been + + + align:start position:0% +state your paper is in. Okay. I've been +looking for other sources to read about. + + align:start position:0% +looking for other sources to read about. + + + align:start position:0% +looking for other sources to read about. +The idea was to do creativity and + + align:start position:0% +The idea was to do creativity and + + + align:start position:0% +The idea was to do creativity and +software development. And I started + + align:start position:0% +software development. And I started + + + align:start position:0% +software development. And I started +thinking about relating it to writing a + + align:start position:0% +thinking about relating it to writing a + + + align:start position:0% +thinking about relating it to writing a +poem. I was talking about that. And I + + align:start position:0% +poem. I was talking about that. And I + + + align:start position:0% +poem. I was talking about that. And I +also started thinking about how, you + + align:start position:0% +also started thinking about how, you + + + align:start position:0% +also started thinking about how, you +know, software engineers tend to not do + + align:start position:0% +know, software engineers tend to not do + + + align:start position:0% +know, software engineers tend to not do +other forms of art generally. Like you + + align:start position:0% +other forms of art generally. Like you + + + align:start position:0% +other forms of art generally. Like you +think of them as like a, you know, + + align:start position:0% +think of them as like a, you know, + + + align:start position:0% +think of them as like a, you know, +software dork at first, you know, a + + align:start position:0% +software dork at first, you know, a + + + align:start position:0% +software dork at first, you know, a +software nerd. And then they don't + + align:start position:0% +software nerd. And then they don't + + + align:start position:0% +software nerd. And then they don't +usually do like the painting and stuff, + + align:start position:0% +usually do like the painting and stuff, + + + align:start position:0% +usually do like the painting and stuff, +but it's a very, very few people + + align:start position:0% +but it's a very, very few people + + + align:start position:0% +but it's a very, very few people +actually do both. I wanted to evaluate + + align:start position:0% +actually do both. I wanted to evaluate + + + align:start position:0% +actually do both. I wanted to evaluate +why that was. You know, if if + + align:start position:0% +why that was. You know, if if + + + align:start position:0% +why that was. You know, if if +programming is created, why don't they + + align:start position:0% +programming is created, why don't they + + + align:start position:0% +programming is created, why don't they +engage in, you know, the standard + + align:start position:0% +engage in, you know, the standard + + + align:start position:0% +engage in, you know, the standard +classical creative acts? Are you in any + + align:start position:0% +classical creative acts? Are you in any + + + align:start position:0% +classical creative acts? Are you in any +danger? Are you in control of the + + align:start position:0% +danger? Are you in control of the + + + align:start position:0% +danger? Are you in control of the +material? Uh, yeah. And you've written + + align:start position:0% +material? Uh, yeah. And you've written + + + align:start position:0% +material? Uh, yeah. And you've written +it and got it going. Yeah. All right. + + align:start position:0% +it and got it going. Yeah. All right. + + + align:start position:0% +it and got it going. Yeah. All right. +So, you'll get it in on time and be + + align:start position:0% +So, you'll get it in on time and be + + + align:start position:0% +So, you'll get it in on time and be +satisfied. Yeah. Hope so. All right. + + align:start position:0% +satisfied. Yeah. Hope so. All right. + + + align:start position:0% +satisfied. Yeah. Hope so. All right. +Megan, the same with you. Um, I'm + + align:start position:0% +Megan, the same with you. Um, I'm + + + align:start position:0% +Megan, the same with you. Um, I'm +writing partially on what I talked about + + align:start position:0% +writing partially on what I talked about + + + align:start position:0% +writing partially on what I talked about +last week, which is creativity and + + align:start position:0% +last week, which is creativity and + + + align:start position:0% +last week, which is creativity and +everyday life. Mostly in an attempt, um, + + align:start position:0% +everyday life. Mostly in an attempt, um, + + + align:start position:0% +everyday life. Mostly in an attempt, um, +in my research, like I find that there's + + align:start position:0% +in my research, like I find that there's + + + align:start position:0% +in my research, like I find that there's +two different ways of looking at + + align:start position:0% +two different ways of looking at + + + align:start position:0% +two different ways of looking at +creativity. There's the the artistic + + align:start position:0% +creativity. There's the the artistic + + + align:start position:0% +creativity. There's the the artistic +sort that refers to what we talk about + + align:start position:0% +sort that refers to what we talk about + + + align:start position:0% +sort that refers to what we talk about +most in this class, and then creativity + + align:start position:0% +most in this class, and then creativity + + + align:start position:0% +most in this class, and then creativity +in like the kid that's putting his toys + + align:start position:0% +in like the kid that's putting his toys + + + align:start position:0% +in like the kid that's putting his toys +away and wants to put the block on the + + align:start position:0% +away and wants to put the block on the + + + align:start position:0% +away and wants to put the block on the +top shelf and finds a way to do it + + align:start position:0% +top shelf and finds a way to do it + + + align:start position:0% +top shelf and finds a way to do it +without any help. even though you know + + align:start position:0% +without any help. even though you know + + + align:start position:0% +without any help. even though you know +his little brother or his older brother + + align:start position:0% +his little brother or his older brother + + + align:start position:0% +his little brother or his older brother +learned to do the same thing, it's still + + align:start position:0% +learned to do the same thing, it's still + + + align:start position:0% +learned to do the same thing, it's still +creative because the kid didn't know + + align:start position:0% +creative because the kid didn't know + + + align:start position:0% +creative because the kid didn't know +that. You know, we don't discuss that + + align:start position:0% +that. You know, we don't discuss that + + + align:start position:0% +that. You know, we don't discuss that +kind of creativity much in this class. + + align:start position:0% +kind of creativity much in this class. + + + align:start position:0% +kind of creativity much in this class. +So, sort of an attempt to to + + align:start position:0% +So, sort of an attempt to to + + + align:start position:0% +So, sort of an attempt to to +link together the two different kinds of + + align:start position:0% +link together the two different kinds of + + + align:start position:0% +link together the two different kinds of +creativity and then um second part of my + + align:start position:0% +creativity and then um second part of my + + + align:start position:0% +creativity and then um second part of my +paper is going to be on creativity and + + align:start position:0% +paper is going to be on creativity and + + + align:start position:0% +paper is going to be on creativity and +intuition. + + align:start position:0% +intuition. + + + align:start position:0% +intuition. +I found two different definitions of + + align:start position:0% +I found two different definitions of + + + align:start position:0% +I found two different definitions of +intuition that support the two different + + align:start position:0% +intuition that support the two different + + + align:start position:0% +intuition that support the two different +definitions of creativity. But in both + + align:start position:0% +definitions of creativity. But in both + + + align:start position:0% +definitions of creativity. But in both +senses intuition is directly linked to + + align:start position:0% +senses intuition is directly linked to + + + align:start position:0% +senses intuition is directly linked to +creativity and okay. So well uh + + align:start position:0% +creativity and okay. So well uh + + + align:start position:0% +creativity and okay. So well uh +particularly for you too if you send me + + align:start position:0% +particularly for you too if you send me + + + align:start position:0% +particularly for you too if you send me +emails + + align:start position:0% +emails + + + align:start position:0% +emails +at any point I mean right immediately or + + align:start position:0% +at any point I mean right immediately or + + + align:start position:0% +at any point I mean right immediately or +tomorrow I'll I'll try to help you + + align:start position:0% +tomorrow I'll I'll try to help you + + + align:start position:0% +tomorrow I'll I'll try to help you +further + + align:start position:0% +further + + + align:start position:0% +further +and in fact that's true of all of you. + + align:start position:0% +and in fact that's true of all of you. + + + align:start position:0% +and in fact that's true of all of you. +Don't despair of uh getting my help up + + align:start position:0% +Don't despair of uh getting my help up + + + align:start position:0% +Don't despair of uh getting my help up +to the very last minute. + + align:start position:0% +to the very last minute. + + + align:start position:0% +to the very last minute. +Good night. \ No newline at end of file diff --git a/wH9nO8_aDSI.txt b/wH9nO8_aDSI.txt new file mode 100644 index 0000000000000000000000000000000000000000..58ba973609f527b397d9ed39bbb9b4c2c52945f8 --- /dev/null +++ b/wH9nO8_aDSI.txt @@ -0,0 +1,18768 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a creative commons license your support + + align:start position:0% +a creative commons license your support + + + align:start position:0% +a creative commons license your support +will help mit opencourseware continue to + + align:start position:0% +will help mit opencourseware continue to + + + align:start position:0% +will help mit opencourseware continue to +offer high quality educational resources + + align:start position:0% +offer high quality educational resources + + + align:start position:0% +offer high quality educational resources +for free + + align:start position:0% +for free + + + align:start position:0% +for free +to make a donation or to view additional + + align:start position:0% +to make a donation or to view additional + + + align:start position:0% +to make a donation or to view additional +materials from hundreds of mit courses + + align:start position:0% +materials from hundreds of mit courses + + + align:start position:0% +materials from hundreds of mit courses +visit mit opencourseware at ocw.mit.edu + + align:start position:0% + + + + align:start position:0% + +so today we're going to do our last uh + + align:start position:0% +so today we're going to do our last uh + + + align:start position:0% +so today we're going to do our last uh +lecture on scattering in quantum + + align:start position:0% +lecture on scattering in quantum + + + align:start position:0% +lecture on scattering in quantum +mechanics in 1d quantum mechanics and + + align:start position:0% +mechanics in 1d quantum mechanics and + + + align:start position:0% +mechanics in 1d quantum mechanics and +we're going to introduce some powerful + + align:start position:0% +we're going to introduce some powerful + + + align:start position:0% +we're going to introduce some powerful +ideas in particular the phase shift and + + align:start position:0% +ideas in particular the phase shift and + + + align:start position:0% +ideas in particular the phase shift and +the s matrix and they're cool we'll use + + align:start position:0% +the s matrix and they're cool we'll use + + + align:start position:0% +the s matrix and they're cool we'll use +them for good before we get started + + align:start position:0% +them for good before we get started + + + align:start position:0% +them for good before we get started +questions + + align:start position:0% +questions + + + align:start position:0% +questions +from last time + + align:start position:0% + + + + align:start position:0% + +just now it's a band called saint + + align:start position:0% +just now it's a band called saint + + + align:start position:0% +just now it's a band called saint +germain um + + align:start position:0% +germain um + + + align:start position:0% +germain um +it's actually a guy + + align:start position:0% +it's actually a guy + + + align:start position:0% +it's actually a guy +but he's refers to himself as a band + + align:start position:0% +but he's refers to himself as a band + + + align:start position:0% +but he's refers to himself as a band +called cengermain anyway it's from an + + align:start position:0% +called cengermain anyway it's from an + + + align:start position:0% +called cengermain anyway it's from an +album i think called traveler + + align:start position:0% +album i think called traveler + + + align:start position:0% +album i think called traveler +physics questions + + align:start position:0% +physics questions + + + align:start position:0% +physics questions +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +anyone + + align:start position:0% +anyone + + + align:start position:0% +anyone +okay good um well bad actually i'd much + + align:start position:0% +okay good um well bad actually i'd much + + + align:start position:0% +okay good um well bad actually i'd much +referred if you had questions but i'll + + align:start position:0% +referred if you had questions but i'll + + + align:start position:0% +referred if you had questions but i'll +take that as a sign of of knowledge + + align:start position:0% +take that as a sign of of knowledge + + + align:start position:0% +take that as a sign of of knowledge +competence and mastery + + align:start position:0% +competence and mastery + + + align:start position:0% +competence and mastery +okay so + + align:start position:0% +okay so + + + align:start position:0% +okay so +yeah so + + align:start position:0% +yeah so + + + align:start position:0% +yeah so +so last time we talked about uh + + align:start position:0% +so last time we talked about uh + + + align:start position:0% +so last time we talked about uh +scattering past a barrier with some + + align:start position:0% +scattering past a barrier with some + + + align:start position:0% +scattering past a barrier with some +height l and some height v which i think + + align:start position:0% +height l and some height v which i think + + + align:start position:0% +height l and some height v which i think +we called v naught + + align:start position:0% +we called v naught + + + align:start position:0% +we called v naught +and we observed a bunch of nice things + + align:start position:0% +and we observed a bunch of nice things + + + align:start position:0% +and we observed a bunch of nice things +about this first off we computed the + + align:start position:0% +about this first off we computed the + + + align:start position:0% +about this first off we computed the +probability of transmission across this + + align:start position:0% +probability of transmission across this + + + align:start position:0% +probability of transmission across this +barrier oops the probability of + + align:start position:0% +barrier oops the probability of + + + align:start position:0% +barrier oops the probability of +transmission across this barrier as a + + align:start position:0% +transmission across this barrier as a + + + align:start position:0% +transmission across this barrier as a +function of the energy and it had a + + align:start position:0% +function of the energy and it had a + + + align:start position:0% +function of the energy and it had a +bunch of nice features first off um it + + align:start position:0% +bunch of nice features first off um it + + + align:start position:0% +bunch of nice features first off um it +asymptoted to one at high energies which + + align:start position:0% +asymptoted to one at high energies which + + + align:start position:0% +asymptoted to one at high energies which +makes sense things shouldn't really care + + align:start position:0% +makes sense things shouldn't really care + + + align:start position:0% +makes sense things shouldn't really care +if you have a little tiny barrier + + align:start position:0% +if you have a little tiny barrier + + + align:start position:0% +if you have a little tiny barrier +it went to zero at zero energy uh that i + + align:start position:0% +it went to zero at zero energy uh that i + + + align:start position:0% +it went to zero at zero energy uh that i +don't know how uh i think we should all + + align:start position:0% +don't know how uh i think we should all + + + align:start position:0% +don't know how uh i think we should all +find that obviously if you have + + align:start position:0% +find that obviously if you have + + + align:start position:0% +find that obviously if you have +extremely low energy you're just going + + align:start position:0% +extremely low energy you're just going + + + align:start position:0% +extremely low energy you're just going +to bounce off this very hard wall + + align:start position:0% +to bounce off this very hard wall + + + align:start position:0% +to bounce off this very hard wall +in between though there's some structure + + align:start position:0% +in between though there's some structure + + + align:start position:0% +in between though there's some structure +and in particular uh at certain values + + align:start position:0% +and in particular uh at certain values + + + align:start position:0% +and in particular uh at certain values +of the energy corresponding to certain + + align:start position:0% +of the energy corresponding to certain + + + align:start position:0% +of the energy corresponding to certain +values of the wave number in the barrier + + align:start position:0% +values of the wave number in the barrier + + + align:start position:0% +values of the wave number in the barrier +region at certain values of the energy + + align:start position:0% +region at certain values of the energy + + + align:start position:0% +region at certain values of the energy +we saw that the transmission was perfect + + align:start position:0% +we saw that the transmission was perfect + + + align:start position:0% +we saw that the transmission was perfect +oops this should have been here sorry + + align:start position:0% +oops this should have been here sorry + + + align:start position:0% +oops this should have been here sorry +the transmission was perfect + + align:start position:0% +the transmission was perfect + + + align:start position:0% +the transmission was perfect +at special values of the energy + + align:start position:0% + + + + align:start position:0% + +and that the reflection + + align:start position:0% +and that the reflection + + + align:start position:0% +and that the reflection +at those points was zero you transmitted + + align:start position:0% +at those points was zero you transmitted + + + align:start position:0% +at those points was zero you transmitted +perfectly + + align:start position:0% +perfectly + + + align:start position:0% +perfectly +but meanwhile the reflection which is + + align:start position:0% +but meanwhile the reflection which is + + + align:start position:0% +but meanwhile the reflection which is +one minus the transmission hit maxima at + + align:start position:0% +one minus the transmission hit maxima at + + + align:start position:0% +one minus the transmission hit maxima at +special points and those special points + + align:start position:0% +special points and those special points + + + align:start position:0% +special points and those special points +turn out to be + + align:start position:0% +turn out to be + + + align:start position:0% +turn out to be +half integer shifted away from the + + align:start position:0% +half integer shifted away from the + + + align:start position:0% +half integer shifted away from the +special points for perfect transmission + + align:start position:0% +special points for perfect transmission + + + align:start position:0% +special points for perfect transmission +so at certain points we have perfect + + align:start position:0% +so at certain points we have perfect + + + align:start position:0% +so at certain points we have perfect +transmission at certain points we have + + align:start position:0% +transmission at certain points we have + + + align:start position:0% +transmission at certain points we have +extremely efficient reflection + + align:start position:0% +extremely efficient reflection + + + align:start position:0% +extremely efficient reflection +and so one of our goals today is going + + align:start position:0% +and so one of our goals today is going + + + align:start position:0% +and so one of our goals today is going +to be to understand + + align:start position:0% +to be to understand + + + align:start position:0% +to be to understand +this physics the physics of resonance in + + align:start position:0% +this physics the physics of resonance in + + + align:start position:0% +this physics the physics of resonance in +scattering off of a potential okay + + align:start position:0% +scattering off of a potential okay + + + align:start position:0% +scattering off of a potential okay +so the asymptotes we understand + + align:start position:0% +so the asymptotes we understand + + + align:start position:0% +so the asymptotes we understand +classically that makes sense classically + + align:start position:0% +classically that makes sense classically + + + align:start position:0% +classically that makes sense classically +that makes sense but classically this is + + align:start position:0% +that makes sense but classically this is + + + align:start position:0% +that makes sense but classically this is +a really weird structure to see + + align:start position:0% +a really weird structure to see + + + align:start position:0% +a really weird structure to see +and notice that it's also not something + + align:start position:0% +and notice that it's also not something + + + align:start position:0% +and notice that it's also not something +that we saw when we looked at scattering + + align:start position:0% +that we saw when we looked at scattering + + + align:start position:0% +that we saw when we looked at scattering +off of a simple step when we looked at a + + align:start position:0% +off of a simple step when we looked at a + + + align:start position:0% +off of a simple step when we looked at a +simple step what we got was something + + align:start position:0% +simple step what we got was something + + + align:start position:0% +simple step what we got was something +that looked like zero + + align:start position:0% +that looked like zero + + + align:start position:0% +that looked like zero +and then + + align:start position:0% +and then + + + align:start position:0% +and then +this + + align:start position:0% +this + + + align:start position:0% +this +right there was no structure it was just + + align:start position:0% +right there was no structure it was just + + + align:start position:0% +right there was no structure it was just +a nice simple curve + + align:start position:0% +a nice simple curve + + + align:start position:0% +a nice simple curve +so something is happening when we have a + + align:start position:0% +so something is happening when we have a + + + align:start position:0% +so something is happening when we have a +barrier as opposed to a step + + align:start position:0% +barrier as opposed to a step + + + align:start position:0% +barrier as opposed to a step +so our job is going to be in some sense + + align:start position:0% +so our job is going to be in some sense + + + align:start position:0% +so our job is going to be in some sense +to answer why are they so different + + align:start position:0% +to answer why are they so different + + + align:start position:0% +to answer why are they so different +before i get going questions about + + align:start position:0% +before i get going questions about + + + align:start position:0% +before i get going questions about +the step + + align:start position:0% +the step + + + align:start position:0% +the step +barrier yeah + + align:start position:0% + + + + align:start position:0% + +is that just scale + + align:start position:0% +is that just scale + + + align:start position:0% +is that just scale +oh sorry um + + align:start position:0% +oh sorry um + + + align:start position:0% +oh sorry um +this one + + align:start position:0% + + + + align:start position:0% + +this that was the transmission sorry i + + align:start position:0% +this that was the transmission sorry i + + + align:start position:0% +this that was the transmission sorry i +should have drawn it separately that was + + align:start position:0% +should have drawn it separately that was + + + align:start position:0% +should have drawn it separately that was +the transmission as um as a function of + + align:start position:0% +the transmission as um as a function of + + + align:start position:0% +the transmission as um as a function of +energy + + align:start position:0% +energy + + + align:start position:0% +energy +across a single step + + align:start position:0% +across a single step + + + align:start position:0% +across a single step +and so that looked like this + + align:start position:0% + + + + align:start position:0% + +exactly oh oh sorry so so i just meant + + align:start position:0% +exactly oh oh sorry so so i just meant + + + align:start position:0% +exactly oh oh sorry so so i just meant +to compare the two i just want to think + + align:start position:0% +to compare the two i just want to think + + + align:start position:0% +to compare the two i just want to think +of them as two different systems in this + + align:start position:0% +of them as two different systems in this + + + align:start position:0% +of them as two different systems in this +system we have + + align:start position:0% +system we have + + + align:start position:0% +system we have +the transmission curve is a nice simple + + align:start position:0% +the transmission curve is a nice simple + + + align:start position:0% +the transmission curve is a nice simple +curve it has no structure in the case of + + align:start position:0% +curve it has no structure in the case of + + + align:start position:0% +curve it has no structure in the case of +a step barrier we get non-zero + + align:start position:0% +a step barrier we get non-zero + + + align:start position:0% +a step barrier we get non-zero +transmission at low energies instead of + + align:start position:0% +transmission at low energies instead of + + + align:start position:0% +transmission at low energies instead of +going to zero and we get this resonant + + align:start position:0% +going to zero and we get this resonant + + + align:start position:0% +going to zero and we get this resonant +structure + + align:start position:0% +structure + + + align:start position:0% +structure +so it's just for contrast + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so before before going into that in + + align:start position:0% +so before before going into that in + + + align:start position:0% +so before before going into that in +detail i wanna do one slight variation + + align:start position:0% +detail i wanna do one slight variation + + + align:start position:0% +detail i wanna do one slight variation +of this problem and i'm not going to do + + align:start position:0% +of this problem and i'm not going to do + + + align:start position:0% +of this problem and i'm not going to do +any of the computations i'm just going + + align:start position:0% +any of the computations i'm just going + + + align:start position:0% +any of the computations i'm just going +to tell you how to get the answer from + + align:start position:0% +to tell you how to get the answer from + + + align:start position:0% +to tell you how to get the answer from +the answers we've already computed + + align:start position:0% +the answers we've already computed + + + align:start position:0% +the answers we've already computed +so consider a barrier a square well you + + align:start position:0% +so consider a barrier a square well you + + + align:start position:0% +so consider a barrier a square well you +guys have solved the finite square well + + align:start position:0% +guys have solved the finite square well + + + align:start position:0% +guys have solved the finite square well +in your problem sets consider finding + + align:start position:0% +in your problem sets consider finding + + + align:start position:0% +in your problem sets consider finding +square well again of width l and of + + align:start position:0% +square well again of width l and of + + + align:start position:0% +square well again of width l and of +depth now minus v naught so it's the + + align:start position:0% +depth now minus v naught so it's the + + + align:start position:0% +depth now minus v naught so it's the +same thing with v goes to minus v + + align:start position:0% +same thing with v goes to minus v + + + align:start position:0% +same thing with v goes to minus v +okay and again i want to consider + + align:start position:0% +okay and again i want to consider + + + align:start position:0% +okay and again i want to consider +scattering states so i want to consider + + align:start position:0% +scattering states so i want to consider + + + align:start position:0% +scattering states so i want to consider +states with positive energy energy above + + align:start position:0% +states with positive energy energy above + + + align:start position:0% +states with positive energy energy above +the asymptotic potential + + align:start position:0% + + + + align:start position:0% + +now at this point by now we all know how + + align:start position:0% +now at this point by now we all know how + + + align:start position:0% +now at this point by now we all know how +to solve this we write plane waves here + + align:start position:0% +to solve this we write plane waves here + + + align:start position:0% +to solve this we write plane waves here +plane waves here we solve and plane + + align:start position:0% +plane waves here we solve and plane + + + align:start position:0% +plane waves here we solve and plane +waves in between we solve the potential + + align:start position:0% +waves in between we solve the potential + + + align:start position:0% +waves in between we solve the potential +in each region where it's constant and + + align:start position:0% +in each region where it's constant and + + + align:start position:0% +in each region where it's constant and +then we impose p uh continuity + + align:start position:0% +then we impose p uh continuity + + + align:start position:0% +then we impose p uh continuity +and of the wave function and continuity + + align:start position:0% +and of the wave function and continuity + + + align:start position:0% +and of the wave function and continuity +the derivative of the wave function at + + align:start position:0% +the derivative of the wave function at + + + align:start position:0% +the derivative of the wave function at +the matching points right so we know how + + align:start position:0% +the matching points right so we know how + + + align:start position:0% +the matching points right so we know how +to solve this problem and deduce the + + align:start position:0% +to solve this problem and deduce the + + + align:start position:0% +to solve this problem and deduce the +transmission reflection coefficients + + align:start position:0% +transmission reflection coefficients + + + align:start position:0% +transmission reflection coefficients +we've done it for this problem and it's + + align:start position:0% +we've done it for this problem and it's + + + align:start position:0% +we've done it for this problem and it's +exactly the same algebra and in fact + + align:start position:0% +exactly the same algebra and in fact + + + align:start position:0% +exactly the same algebra and in fact +it's so exactly the same algebra that we + + align:start position:0% +it's so exactly the same algebra that we + + + align:start position:0% +it's so exactly the same algebra that we +can just take the results from this one + + align:start position:0% +can just take the results from this one + + + align:start position:0% +can just take the results from this one +and take v to minus v and we'll get the + + align:start position:0% +and take v to minus v and we'll get the + + + align:start position:0% +and take v to minus v and we'll get the +right answer + + align:start position:0% +right answer + + + align:start position:0% +right answer +you kind of have to so + + align:start position:0% +you kind of have to so + + + align:start position:0% +you kind of have to so +if we do + + align:start position:0% +if we do + + + align:start position:0% +if we do +what we get for the transmission + + align:start position:0% +what we get for the transmission + + + align:start position:0% +what we get for the transmission +probability + + align:start position:0% + + + + align:start position:0% + +and now this is the transmission + + align:start position:0% +and now this is the transmission + + + align:start position:0% +and now this is the transmission +probability for a square well + + align:start position:0% +probability for a square well + + + align:start position:0% +probability for a square well +and again i'm going to use the same + + align:start position:0% +and again i'm going to use the same + + + align:start position:0% +and again i'm going to use the same +dimensionless constants g naught squared + + align:start position:0% +dimensionless constants g naught squared + + + align:start position:0% +dimensionless constants g naught squared +is equal to + + align:start position:0% +is equal to + + + align:start position:0% +is equal to +2m l squared over h bar squared times v + + align:start position:0% +2m l squared over h bar squared times v + + + align:start position:0% +2m l squared over h bar squared times v +naught this is 1 over an energy this is + + align:start position:0% +naught this is 1 over an energy this is + + + align:start position:0% +naught this is 1 over an energy this is +an energy this is dimensionless and the + + align:start position:0% +an energy this is dimensionless and the + + + align:start position:0% +an energy this is dimensionless and the +dimensionless energy epsilon is equal to + + align:start position:0% +dimensionless energy epsilon is equal to + + + align:start position:0% +dimensionless energy epsilon is equal to +e over v to express my transmission + + align:start position:0% +e over v to express my transmission + + + align:start position:0% +e over v to express my transmission +probability life is better when it's + + align:start position:0% +probability life is better when it's + + + align:start position:0% +probability life is better when it's +dimensionless + + align:start position:0% +dimensionless + + + align:start position:0% +dimensionless +so t the transmission probability is + + align:start position:0% +so t the transmission probability is + + + align:start position:0% +so t the transmission probability is +again it's one of these horrible one + + align:start position:0% +again it's one of these horrible one + + + align:start position:0% +again it's one of these horrible one +overs one over 1 plus + + align:start position:0% +overs one over 1 plus + + + align:start position:0% +overs one over 1 plus +1 over 4 epsilon epsilon + + align:start position:0% +1 over 4 epsilon epsilon + + + align:start position:0% +1 over 4 epsilon epsilon +plus 1. + + align:start position:0% + + + + align:start position:0% + +good sine squared of g naught + + align:start position:0% +good sine squared of g naught + + + align:start position:0% +good sine squared of g naught +square root of epsilon plus 1. + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% +and + + + align:start position:0% +and +this is again the same so if you + + align:start position:0% +this is again the same so if you + + + align:start position:0% +this is again the same so if you +remember last time + + align:start position:0% +remember last time + + + align:start position:0% +remember last time +you can see what we got last time by now + + align:start position:0% +you can see what we got last time by now + + + align:start position:0% +you can see what we got last time by now +taking v to minus v again that takes + + align:start position:0% +taking v to minus v again that takes + + + align:start position:0% +taking v to minus v again that takes +epsilon to minus epsilon so we get out + + align:start position:0% +epsilon to minus epsilon so we get out + + + align:start position:0% +epsilon to minus epsilon so we get out +epsilon a one minus epsilon or epsilon + + align:start position:0% +epsilon a one minus epsilon or epsilon + + + align:start position:0% +epsilon a one minus epsilon or epsilon +minus one picking up the minus sign from + + align:start position:0% +minus one picking up the minus sign from + + + align:start position:0% +minus one picking up the minus sign from +this epsilon + + align:start position:0% +this epsilon + + + align:start position:0% +this epsilon +um and here we get a one minus epsilon + + align:start position:0% +um and here we get a one minus epsilon + + + align:start position:0% +um and here we get a one minus epsilon +instead of one plus epsilon that's + + align:start position:0% +instead of one plus epsilon that's + + + align:start position:0% +instead of one plus epsilon that's +precisely what we got last time + + align:start position:0% +precisely what we got last time + + + align:start position:0% +precisely what we got last time +so if you're feeling punchy at home + + align:start position:0% +so if you're feeling punchy at home + + + align:start position:0% +so if you're feeling punchy at home +tonight + + align:start position:0% +tonight + + + align:start position:0% +tonight +check this + + align:start position:0% +check this + + + align:start position:0% +check this +in some sense you're going to rederive + + align:start position:0% +in some sense you're going to rederive + + + align:start position:0% +in some sense you're going to rederive +it on the problem set + + align:start position:0% + + + + align:start position:0% + +okay so + + align:start position:0% +okay so + + + align:start position:0% +okay so +it looks basically the same as before we + + align:start position:0% +it looks basically the same as before we + + + align:start position:0% +it looks basically the same as before we +have a sine function downstairs which + + align:start position:0% +have a sine function downstairs which + + + align:start position:0% +have a sine function downstairs which +again will sometimes be zero the sine + + align:start position:0% +again will sometimes be zero the sine + + + align:start position:0% +again will sometimes be zero the sine +will occasionally be b0 when it's + + align:start position:0% +will occasionally be b0 when it's + + + align:start position:0% +will occasionally be b0 when it's +argument is a multiple of pi and when + + align:start position:0% +argument is a multiple of pi and when + + + align:start position:0% +argument is a multiple of pi and when +that sine function is zero then the + + align:start position:0% +that sine function is zero then the + + + align:start position:0% +that sine function is zero then the +transmission probability is one over one + + align:start position:0% +transmission probability is one over one + + + align:start position:0% +transmission probability is one over one +plus zero it's also known as one + + align:start position:0% +plus zero it's also known as one + + + align:start position:0% +plus zero it's also known as one +transmission is perfect so we again get + + align:start position:0% +transmission is perfect so we again get + + + align:start position:0% +transmission is perfect so we again get +a resonant structure and it's in fact + + align:start position:0% +a resonant structure and it's in fact + + + align:start position:0% +a resonant structure and it's in fact +exactly the same plot or almost exactly + + align:start position:0% +exactly the same plot or almost exactly + + + align:start position:0% +exactly the same plot or almost exactly +the same plot so um i'm going to plot + + align:start position:0% +the same plot so um i'm going to plot + + + align:start position:0% +the same plot so um i'm going to plot +transmission + + align:start position:0% +transmission + + + align:start position:0% +transmission +let's go ahead and do this transmission + + align:start position:0% +let's go ahead and do this transmission + + + align:start position:0% +let's go ahead and do this transmission +probability as a function again of the + + align:start position:0% +probability as a function again of the + + + align:start position:0% +probability as a function again of the +dimensionless energy + + align:start position:0% +dimensionless energy + + + align:start position:0% +dimensionless energy +and what we get + + align:start position:0% + + + + align:start position:0% + +is again oops + + align:start position:0% +is again oops + + + align:start position:0% +is again oops +not very well drawn + + align:start position:0% + + + + align:start position:0% + +resonances + + align:start position:0% +resonances + + + align:start position:0% +resonances +where transmission goes to one + + align:start position:0% +where transmission goes to one + + + align:start position:0% +where transmission goes to one +thanks to my beautiful artistic skills + + align:start position:0% +thanks to my beautiful artistic skills + + + align:start position:0% +thanks to my beautiful artistic skills +points where the resonance or the where + + align:start position:0% +points where the resonance or the where + + + align:start position:0% +points where the resonance or the where +the reflection hits a local maximum + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +but we know one more thing about this + + align:start position:0% +but we know one more thing about this + + + align:start position:0% +but we know one more thing about this +system which is that in addition to + + align:start position:0% +system which is that in addition to + + + align:start position:0% +system which is that in addition to +having scattering states + + align:start position:0% +having scattering states + + + align:start position:0% +having scattering states +whose transmission probability are + + align:start position:0% +whose transmission probability are + + + align:start position:0% +whose transmission probability are +indicated by this plot we know we also + + align:start position:0% +indicated by this plot we know we also + + + align:start position:0% +indicated by this plot we know we also +have for negative energy bound states + + align:start position:0% +have for negative energy bound states + + + align:start position:0% +have for negative energy bound states +right unlike the step barrier for the + + align:start position:0% +right unlike the step barrier for the + + + align:start position:0% +right unlike the step barrier for the +step well we also have bound states so + + align:start position:0% +step well we also have bound states so + + + align:start position:0% +step well we also have bound states so +here's the transmission curve but i just + + align:start position:0% +here's the transmission curve but i just + + + align:start position:0% +here's the transmission curve but i just +want to remind you that we have energies + + align:start position:0% +want to remind you that we have energies + + + align:start position:0% +want to remind you that we have energies +at special values of energies we also + + align:start position:0% +at special values of energies we also + + + align:start position:0% +at special values of energies we also +have + + align:start position:0% +have + + + align:start position:0% +have +bound states + + align:start position:0% +bound states + + + align:start position:0% +bound states +and precisely what energies depends on + + align:start position:0% +and precisely what energies depends on + + + align:start position:0% +and precisely what energies depends on +the structure of the well and the depth + + align:start position:0% +the structure of the well and the depth + + + align:start position:0% +the structure of the well and the depth +but if the depth of the well is say v + + align:start position:0% +but if the depth of the well is say v + + + align:start position:0% +but if the depth of the well is say v +naught + + align:start position:0% +naught + + + align:start position:0% +naught +so this is minus one + + align:start position:0% +so this is minus one + + + align:start position:0% +so this is minus one +we know that the lowest bound state is + + align:start position:0% +we know that the lowest bound state is + + + align:start position:0% +we know that the lowest bound state is +always greater energy than the bottom of + + align:start position:0% +always greater energy than the bottom of + + + align:start position:0% +always greater energy than the bottom of +the well + + align:start position:0% +the well + + + align:start position:0% +the well +cool + + align:start position:0% +cool + + + align:start position:0% +cool +so epsilon remember is e over v naught + + align:start position:0% +so epsilon remember is e over v naught + + + align:start position:0% +so epsilon remember is e over v naught +and in the square well of depth v naught + + align:start position:0% +and in the square well of depth v naught + + + align:start position:0% +and in the square well of depth v naught +the lowest bound state cannot possibly + + align:start position:0% +the lowest bound state cannot possibly + + + align:start position:0% +the lowest bound state cannot possibly +have energy lower than the bottom of the + + align:start position:0% +have energy lower than the bottom of the + + + align:start position:0% +have energy lower than the bottom of the +well so its epsilon must have epsilon + + align:start position:0% +well so its epsilon must have epsilon + + + align:start position:0% +well so its epsilon must have epsilon +greater than one or minus one + + align:start position:0% +greater than one or minus one + + + align:start position:0% +greater than one or minus one +cool anyway this is just to remind you + + align:start position:0% +cool anyway this is just to remind you + + + align:start position:0% +cool anyway this is just to remind you +that there are bound states + + align:start position:0% +that there are bound states + + + align:start position:0% +that there are bound states +and um + + align:start position:0% +and um + + + align:start position:0% +and um +think of this like a gun put down on a + + align:start position:0% +think of this like a gun put down on a + + + align:start position:0% +think of this like a gun put down on a +table in a play in act one + + align:start position:0% +table in a play in act one + + + align:start position:0% +table in a play in act one +okay + + align:start position:0% + + + + align:start position:0% + +it's that dramatic + + align:start position:0% +it's that dramatic + + + align:start position:0% +it's that dramatic +so it will show up again it will come + + align:start position:0% +so it will show up again it will come + + + align:start position:0% +so it will show up again it will come +back + + align:start position:0% +back + + + align:start position:0% +back +and play well with us so + + align:start position:0% +and play well with us so + + + align:start position:0% +and play well with us so +i want to talk about these residences so + + align:start position:0% +i want to talk about these residences so + + + align:start position:0% +i want to talk about these residences so +let's understand why they're there + + align:start position:0% +let's understand why they're there + + + align:start position:0% +let's understand why they're there +so there are a bunch of ways of + + align:start position:0% +so there are a bunch of ways of + + + align:start position:0% +so there are a bunch of ways of +understanding why these resonances are + + align:start position:0% +understanding why these resonances are + + + align:start position:0% +understanding why these resonances are +present + + align:start position:0% +present + + + align:start position:0% +present +and let me just + + align:start position:0% +and let me just + + + align:start position:0% +and let me just +give you a couple + + align:start position:0% +give you a couple + + + align:start position:0% +give you a couple +so first a heuristic picture and then i + + align:start position:0% +so first a heuristic picture and then i + + + align:start position:0% +so first a heuristic picture and then i +want to give you a very precise + + align:start position:0% +want to give you a very precise + + + align:start position:0% +want to give you a very precise +computational picture of why these + + align:start position:0% +computational picture of why these + + + align:start position:0% +computational picture of why these +resonances are happening so the first is + + align:start position:0% +resonances are happening so the first is + + + align:start position:0% +resonances are happening so the first is +imagine we have a state where the + + align:start position:0% +imagine we have a state where the + + + align:start position:0% +imagine we have a state where the +transmission is perfect what that tells + + align:start position:0% +transmission is perfect what that tells + + + align:start position:0% +transmission is perfect what that tells +you is kl is a multiple of pi + + align:start position:0% +you is kl is a multiple of pi + + + align:start position:0% +you is kl is a multiple of pi +so in here + + align:start position:0% +so in here + + + align:start position:0% +so in here +so if this is the distance l of the well + + align:start position:0% +so if this is the distance l of the well + + + align:start position:0% +so if this is the distance l of the well +in here the wave is exactly one period + + align:start position:0% +in here the wave is exactly one period + + + align:start position:0% +in here the wave is exactly one period +or if it's kale is equal to + + align:start position:0% +or if it's kale is equal to + + + align:start position:0% +or if it's kale is equal to +two to a multiple of pi um so if kl is + + align:start position:0% +two to a multiple of pi um so if kl is + + + align:start position:0% +two to a multiple of pi um so if kl is +pi + + align:start position:0% +pi + + + align:start position:0% +pi +whoops i think i want do i want two + + align:start position:0% + + + + align:start position:0% + +good let me simplify my life and + + align:start position:0% +good let me simplify my life and + + + align:start position:0% +good let me simplify my life and +consider the case kale is two pie so + + align:start position:0% +consider the case kale is two pie so + + + align:start position:0% +consider the case kale is two pie so +when the wave comes through and becomes + + align:start position:0% + + + + align:start position:0% + +oh i know why shoot so for this + + align:start position:0% + + + + align:start position:0% + +sorry + + align:start position:0% +sorry + + + align:start position:0% +sorry +four pi so um i switched notations for + + align:start position:0% +four pi so um i switched notations for + + + align:start position:0% +four pi so um i switched notations for +you i was using in my head uh and or + + align:start position:0% +you i was using in my head uh and or + + + align:start position:0% +you i was using in my head uh and or +rather in my notes uh width of the well + + align:start position:0% +rather in my notes uh width of the well + + + align:start position:0% +rather in my notes uh width of the well +is 2l from + + align:start position:0% +is 2l from + + + align:start position:0% +is 2l from +um + + align:start position:0% +um + + + align:start position:0% +um +uh + + align:start position:0% +uh + + + align:start position:0% +uh +for reasons you'll see on the notes if + + align:start position:0% +for reasons you'll see on the notes if + + + align:start position:0% +for reasons you'll see on the notes if +you look at the notes but let's ignore + + align:start position:0% +you look at the notes but let's ignore + + + align:start position:0% +you look at the notes but let's ignore +that let's focus on these guys so + + align:start position:0% +that let's focus on these guys so + + + align:start position:0% +that let's focus on these guys so +consider the state + + align:start position:0% +consider the state + + + align:start position:0% +consider the state +a configuration in energy such that in + + align:start position:0% +a configuration in energy such that in + + + align:start position:0% +a configuration in energy such that in +the well we have exactly one period of + + align:start position:0% +the well we have exactly one period of + + + align:start position:0% +the well we have exactly one period of +the wave function that means that the + + align:start position:0% +the wave function that means that the + + + align:start position:0% +the wave function that means that the +value of the wave function at the two + + align:start position:0% +value of the wave function at the two + + + align:start position:0% +value of the wave function at the two +ends is the same and the slope is the + + align:start position:0% +ends is the same and the slope is the + + + align:start position:0% +ends is the same and the slope is the +same + + align:start position:0% +same + + + align:start position:0% +same +so whatever the energy is out here + + align:start position:0% + + + + align:start position:0% + +if it matches smoothly continuously and + + align:start position:0% +if it matches smoothly continuously and + + + align:start position:0% +if it matches smoothly continuously and +its derivative is continuous here it + + align:start position:0% +its derivative is continuous here it + + + align:start position:0% +its derivative is continuous here it +will match smoothly and continuously out + + align:start position:0% +will match smoothly and continuously out + + + align:start position:0% +will match smoothly and continuously out +here as well with the same + + align:start position:0% +here as well with the same + + + align:start position:0% +here as well with the same +amplitude and the same + + align:start position:0% +amplitude and the same + + + align:start position:0% +amplitude and the same +period inside and outside + + align:start position:0% +period inside and outside + + + align:start position:0% +period inside and outside +right the amplitude is the same in the + + align:start position:0% +right the amplitude is the same in the + + + align:start position:0% +right the amplitude is the same in the +phases the same that means this wave + + align:start position:0% +phases the same that means this wave + + + align:start position:0% +phases the same that means this wave +must have the same amplitude in the same + + align:start position:0% +must have the same amplitude in the same + + + align:start position:0% +must have the same amplitude in the same +period well it has to have the same + + align:start position:0% +period well it has to have the same + + + align:start position:0% +period well it has to have the same +period is the same energy but must have + + align:start position:0% +period is the same energy but must have + + + align:start position:0% +period is the same energy but must have +the same amplitude and the same slope at + + align:start position:0% +the same amplitude and the same slope at + + + align:start position:0% +the same amplitude and the same slope at +that point + + align:start position:0% +that point + + + align:start position:0% +that point +and that means that this wave has the + + align:start position:0% +and that means that this wave has the + + + align:start position:0% +and that means that this wave has the +same amplitude as this wave the norm + + align:start position:0% +same amplitude as this wave the norm + + + align:start position:0% +same amplitude as this wave the norm +squared + + align:start position:0% +squared + + + align:start position:0% +squared +is the transmission probability norm + + align:start position:0% +is the transmission probability norm + + + align:start position:0% +is the transmission probability norm +squared of this divided by the normal + + align:start position:0% +squared of this divided by the normal + + + align:start position:0% +squared of this divided by the normal +square of this that means the + + align:start position:0% +square of this that means the + + + align:start position:0% +square of this that means the +transmission probability has to be one + + align:start position:0% +transmission probability has to be one + + + align:start position:0% +transmission probability has to be one +what would have happened had the system + + align:start position:0% +what would have happened had the system + + + align:start position:0% +what would have happened had the system +instead of being perfectly periodic + + align:start position:0% +instead of being perfectly periodic + + + align:start position:0% +instead of being perfectly periodic +inside the well well let me actually let + + align:start position:0% +inside the well well let me actually let + + + align:start position:0% +inside the well well let me actually let +me leave that up + + align:start position:0% + + + + align:start position:0% + +so we + + align:start position:0% +so we + + + align:start position:0% +so we +have let's do it as this + + align:start position:0% + + + + align:start position:0% + +oh shoot i'm even getting my qualitative + + align:start position:0% +oh shoot i'm even getting my qualitative + + + align:start position:0% +oh shoot i'm even getting my qualitative +wave functions wrong let's try this + + align:start position:0% +wave functions wrong let's try this + + + align:start position:0% +wave functions wrong let's try this +again + + align:start position:0% +again + + + align:start position:0% +again +okay start at the top go down and then + + align:start position:0% +okay start at the top go down and then + + + align:start position:0% +okay start at the top go down and then +it's got a lower uh uh it's deeper + + align:start position:0% +it's got a lower uh uh it's deeper + + + align:start position:0% +it's got a lower uh uh it's deeper +inside the well so the amplitude out + + align:start position:0% +inside the well so the amplitude out + + + align:start position:0% +inside the well so the amplitude out +here the the potent the difference in + + align:start position:0% +here the the potent the difference in + + + align:start position:0% +here the the potent the difference in +energy between the energy and the + + align:start position:0% +energy between the energy and the + + + align:start position:0% +energy between the energy and the +potential is less which means the period + + align:start position:0% +potential is less which means the period + + + align:start position:0% +potential is less which means the period +is longer and the amplitude is greater + + align:start position:0% +is longer and the amplitude is greater + + + align:start position:0% +is longer and the amplitude is greater +but it's the way i've drawn it it's got + + align:start position:0% +but it's the way i've drawn it it's got + + + align:start position:0% +but it's the way i've drawn it it's got +a particular value it's got zero + + align:start position:0% +a particular value it's got zero + + + align:start position:0% +a particular value it's got zero +um + + align:start position:0% +um + + + align:start position:0% +um +zero uh + + align:start position:0% +zero uh + + + align:start position:0% +zero uh +uh + + align:start position:0% +uh + + + align:start position:0% +uh +uh + + align:start position:0% +uh + + + align:start position:0% +uh +derivative at this point + + align:start position:0% +derivative at this point + + + align:start position:0% +derivative at this point +so it's got two + + align:start position:0% + + + + align:start position:0% + +okay good so there's our wavefunction + + align:start position:0% +okay good so there's our wavefunction + + + align:start position:0% +okay good so there's our wavefunction +same thing out here + + align:start position:0% + + + + align:start position:0% + +but the important thing is the amplitude + + align:start position:0% +but the important thing is the amplitude + + + align:start position:0% +but the important thing is the amplitude +here has to be the same as the amplitude + + align:start position:0% +here has to be the same as the amplitude + + + align:start position:0% +here has to be the same as the amplitude +here because the amplitude and the + + align:start position:0% +here because the amplitude and the + + + align:start position:0% +here because the amplitude and the +amplitude in the phase were exactly as + + align:start position:0% +amplitude in the phase were exactly as + + + align:start position:0% +amplitude in the phase were exactly as +if there had been no intervening region + + align:start position:0% +if there had been no intervening region + + + align:start position:0% +if there had been no intervening region +wouldn't agree with that + + align:start position:0% +wouldn't agree with that + + + align:start position:0% +wouldn't agree with that +by contrast if we had looked at a + + align:start position:0% +by contrast if we had looked at a + + + align:start position:0% +by contrast if we had looked at a +situation where inside the well + + align:start position:0% +situation where inside the well + + + align:start position:0% +situation where inside the well +it was not the same amplitude so for + + align:start position:0% +it was not the same amplitude so for + + + align:start position:0% +it was not the same amplitude so for +example + + align:start position:0% + + + + align:start position:0% + +something like this + + align:start position:0% +something like this + + + align:start position:0% +something like this +came up with some slope which is + + align:start position:0% +came up with some slope which is + + + align:start position:0% +came up with some slope which is +different in a value which was different + + align:start position:0% +different in a value which was different + + + align:start position:0% +different in a value which was different +then this is going to match onto + + align:start position:0% +then this is going to match onto + + + align:start position:0% +then this is going to match onto +something with the same period but with + + align:start position:0% +something with the same period but with + + + align:start position:0% +something with the same period but with +a different amplitude + + align:start position:0% +a different amplitude + + + align:start position:0% +a different amplitude +than it would have + + align:start position:0% +than it would have + + + align:start position:0% +than it would have +over here + + align:start position:0% + + + + align:start position:0% + +same period because it's got the same + + align:start position:0% +same period because it's got the same + + + align:start position:0% +same period because it's got the same +energy but a different amplitude because + + align:start position:0% +energy but a different amplitude because + + + align:start position:0% +energy but a different amplitude because +it has to match on with the value and + + align:start position:0% +it has to match on with the value and + + + align:start position:0% +it has to match on with the value and +the derivative + + align:start position:0% +the derivative + + + align:start position:0% +the derivative +so + + align:start position:0% +so + + + align:start position:0% +so +you can think through this and pretty + + align:start position:0% +you can think through this and pretty + + + align:start position:0% +you can think through this and pretty +quickly convince yourself of + + align:start position:0% +quickly convince yourself of + + + align:start position:0% +quickly convince yourself of +the necessity of the transmission + + align:start position:0% +the necessity of the transmission + + + align:start position:0% +the necessity of the transmission +amplitude being one if this is exactly + + align:start position:0% +amplitude being one if this is exactly + + + align:start position:0% +amplitude being one if this is exactly +periodic + + align:start position:0% +periodic + + + align:start position:0% +periodic +again if this is exactly one period + + align:start position:0% +again if this is exactly one period + + + align:start position:0% +again if this is exactly one period +inside you can just imagine this is gone + + align:start position:0% +inside you can just imagine this is gone + + + align:start position:0% +inside you can just imagine this is gone +and you get a continuous wave function + + align:start position:0% +and you get a continuous wave function + + + align:start position:0% +and you get a continuous wave function +so the amplitude and the derivative must + + align:start position:0% +so the amplitude and the derivative must + + + align:start position:0% +so the amplitude and the derivative must +be the same on both sides + + align:start position:0% +be the same on both sides + + + align:start position:0% +be the same on both sides +as if there is no barrier there and when + + align:start position:0% +as if there is no barrier there and when + + + align:start position:0% +as if there is no barrier there and when +the phases uh when the phase is not same + + align:start position:0% +the phases uh when the phase is not same + + + align:start position:0% +the phases uh when the phase is not same +here when the wave function doesn't have + + align:start position:0% +here when the wave function doesn't have + + + align:start position:0% +here when the wave function doesn't have +exactly one period inside the well you + + align:start position:0% +exactly one period inside the well you + + + align:start position:0% +exactly one period inside the well you +can't do that + + align:start position:0% +can't do that + + + align:start position:0% +can't do that +so the amplitudes can't be the same on + + align:start position:0% +so the amplitudes can't be the same on + + + align:start position:0% +so the amplitudes can't be the same on +both sides + + align:start position:0% +both sides + + + align:start position:0% +both sides +okay but that's not a very satisfying + + align:start position:0% +okay but that's not a very satisfying + + + align:start position:0% +okay but that's not a very satisfying +explanation that's really an explanation + + align:start position:0% +explanation that's really an explanation + + + align:start position:0% +explanation that's really an explanation +about solutions to the differential + + align:start position:0% +about solutions to the differential + + + align:start position:0% +about solutions to the differential +equation i'm just telling you properties + + align:start position:0% +equation i'm just telling you properties + + + align:start position:0% +equation i'm just telling you properties +of second-order differential equations + + align:start position:0% +of second-order differential equations + + + align:start position:0% +of second-order differential equations +let's think of a more physical more + + align:start position:0% +let's think of a more physical more + + + align:start position:0% +let's think of a more physical more +quantum mechanical explanation why are + + align:start position:0% +quantum mechanical explanation why are + + + align:start position:0% +quantum mechanical explanation why are +we getting these resonances + + align:start position:0% +we getting these resonances + + + align:start position:0% +we getting these resonances +well i want to think about this in the + + align:start position:0% +well i want to think about this in the + + + align:start position:0% +well i want to think about this in the +same way as we thought about the boxes + + align:start position:0% +same way as we thought about the boxes + + + align:start position:0% +same way as we thought about the boxes +in the very first lecture + + align:start position:0% + + + + align:start position:0% + +suppose + + align:start position:0% + + + + align:start position:0% + +we have this square well + + align:start position:0% +we have this square well + + + align:start position:0% +we have this square well +and i know i have some amplitude here + + align:start position:0% +and i know i have some amplitude here + + + align:start position:0% +and i know i have some amplitude here +and i want to know with some i've got a + + align:start position:0% +and i want to know with some i've got a + + + align:start position:0% +and i want to know with some i've got a +wave function it's got some amplitude + + align:start position:0% +wave function it's got some amplitude + + + align:start position:0% +wave function it's got some amplitude +here it's got some momentum going this + + align:start position:0% +here it's got some momentum going this + + + align:start position:0% +here it's got some momentum going this +way some positive momentum and i want to + + align:start position:0% +way some positive momentum and i want to + + + align:start position:0% +way some positive momentum and i want to +ask + + align:start position:0% +ask + + + align:start position:0% +ask +what's the probability that i will + + align:start position:0% +what's the probability that i will + + + align:start position:0% +what's the probability that i will +scatter past the potential let's say to + + align:start position:0% +scatter past the potential let's say to + + + align:start position:0% +scatter past the potential let's say to +this point right here just on the other + + align:start position:0% +this point right here just on the other + + + align:start position:0% +this point right here just on the other +side of the potential what's the + + align:start position:0% +side of the potential what's the + + + align:start position:0% +side of the potential what's the +probability that i will scatter across + + align:start position:0% +probability that i will scatter across + + + align:start position:0% +probability that i will scatter across +well you say we've done this calculation + + align:start position:0% +well you say we've done this calculation + + + align:start position:0% +well you say we've done this calculation +we know the probability to transmit + + align:start position:0% +we know the probability to transmit + + + align:start position:0% +we know the probability to transmit +across this step potential we did that + + align:start position:0% +across this step potential we did that + + + align:start position:0% +across this step potential we did that +last time + + align:start position:0% +last time + + + align:start position:0% +last time +so that's t step + + align:start position:0% +so that's t step + + + align:start position:0% +so that's t step +and we know the probability we know what + + align:start position:0% +and we know the probability we know what + + + align:start position:0% +and we know the probability we know what +happens to the phase of the wave + + align:start position:0% +happens to the phase of the wave + + + align:start position:0% +happens to the phase of the wave +function or sorry we know the + + align:start position:0% +function or sorry we know the + + + align:start position:0% +function or sorry we know the +probability of scattering across this + + align:start position:0% +probability of scattering across this + + + align:start position:0% +probability of scattering across this +potential step + + align:start position:0% +potential step + + + align:start position:0% +potential step +and that's transmission uh + + align:start position:0% +and that's transmission uh + + + align:start position:0% +and that's transmission uh +up + + align:start position:0% +up + + + align:start position:0% +up +and so the probability that you transmit + + align:start position:0% +and so the probability that you transmit + + + align:start position:0% +and so the probability that you transmit +from here to here is the probability you + + align:start position:0% +from here to here is the probability you + + + align:start position:0% +from here to here is the probability you +transmit here first and then the + + align:start position:0% +transmit here first and then the + + + align:start position:0% +transmit here first and then the +probability that you transmit here right + + align:start position:0% +probability that you transmit here right + + + align:start position:0% +probability that you transmit here right +the product of the probabilities + + align:start position:0% +the product of the probabilities + + + align:start position:0% +the product of the probabilities +sound reasonable + + align:start position:0% + + + + align:start position:0% + +okay let's vote how many people think + + align:start position:0% +okay let's vote how many people think + + + align:start position:0% +okay let's vote how many people think +that this is equal to the transmission + + align:start position:0% +that this is equal to the transmission + + + align:start position:0% +that this is equal to the transmission +probability + + align:start position:0% +probability + + + align:start position:0% +probability +across the potential well + + align:start position:0% + + + + align:start position:0% + +any votes you have to vote one way or + + align:start position:0% +any votes you have to vote one way or + + + align:start position:0% +any votes you have to vote one way or +the other no it is not how many people + + align:start position:0% +the other no it is not how many people + + + align:start position:0% +the other no it is not how many people +vote + + align:start position:0% +vote + + + align:start position:0% +vote +okay yes it is + + align:start position:0% +okay yes it is + + + align:start position:0% +okay yes it is +okay the nose have it and that's not + + align:start position:0% +okay the nose have it and that's not + + + align:start position:0% +okay the nose have it and that's not +terribly surprising uh because of course + + align:start position:0% +terribly surprising uh because of course + + + align:start position:0% +terribly surprising uh because of course +these have no resonance structure so + + align:start position:0% +these have no resonance structure so + + + align:start position:0% +these have no resonance structure so +where did that come from if it's just + + align:start position:0% +where did that come from if it's just + + + align:start position:0% +where did that come from if it's just +that thing squared + + align:start position:0% +that thing squared + + + align:start position:0% +that thing squared +right so that probably can't be it but + + align:start position:0% +right so that probably can't be it but + + + align:start position:0% +right so that probably can't be it but +here's the better here's the the bigger + + align:start position:0% +here's the better here's the the bigger + + + align:start position:0% +here's the better here's the the bigger +problem why is this the wrong argument + + align:start position:0% + + + + align:start position:0% + +because there's reflection yeah exactly + + align:start position:0% +because there's reflection yeah exactly + + + align:start position:0% +because there's reflection yeah exactly +there's reflection but that's only one + + align:start position:0% +there's reflection but that's only one + + + align:start position:0% +there's reflection but that's only one +step in the answer of why it's the wrong + + align:start position:0% +step in the answer of why it's the wrong + + + align:start position:0% +step in the answer of why it's the wrong +answer why else + + align:start position:0% +answer why else + + + align:start position:0% +answer why else +uh your transmission definitions have to + + align:start position:0% +uh your transmission definitions have to + + + align:start position:0% +uh your transmission definitions have to +do far away that's true but i just want + + align:start position:0% +do far away that's true but i just want + + + align:start position:0% +do far away that's true but i just want +the probability if i got here with + + align:start position:0% +the probability if i got here with + + + align:start position:0% +the probability if i got here with +positive momentum i'm eventually going + + align:start position:0% +positive momentum i'm eventually going + + + align:start position:0% +positive momentum i'm eventually going +to get out to infinity so it's the same + + align:start position:0% +to get out to infinity so it's the same + + + align:start position:0% +to get out to infinity so it's the same +probability + + align:start position:0% +probability + + + align:start position:0% +probability +because it's just an e to the ik x out + + align:start position:0% +because it's just an e to the ik x out + + + align:start position:0% +because it's just an e to the ik x out +here the wave function is just e to the + + align:start position:0% +here the wave function is just e to the + + + align:start position:0% +here the wave function is just e to the +ikx + + align:start position:0% +ikx + + + align:start position:0% +ikx +so the probability is going to be the + + align:start position:0% +so the probability is going to be the + + + align:start position:0% +so the probability is going to be the +same + + align:start position:0% +same + + + align:start position:0% +same +other + + align:start position:0% +other + + + align:start position:0% +other +well the reasons of the well is very + + align:start position:0% +well the reasons of the well is very + + + align:start position:0% +well the reasons of the well is very +important but the first argument ignores + + align:start position:0% +important but the first argument ignores + + + align:start position:0% +important but the first argument ignores +that exactly that's also true so far the + + align:start position:0% +that exactly that's also true so far the + + + align:start position:0% +that exactly that's also true so far the +reasons we have are we need the width of + + align:start position:0% +reasons we have are we need the width of + + + align:start position:0% +reasons we have are we need the width of +the well doesn't appear + + align:start position:0% +the well doesn't appear + + + align:start position:0% +the well doesn't appear +that seems probably wrong + + align:start position:0% +that seems probably wrong + + + align:start position:0% +that seems probably wrong +okay + + align:start position:0% +okay + + + align:start position:0% +okay +uh the second is it's possible that you + + align:start position:0% +uh the second is it's possible that you + + + align:start position:0% +uh the second is it's possible that you +could have reflected we haven't really + + align:start position:0% +could have reflected we haven't really + + + align:start position:0% +could have reflected we haven't really +incorporated that in any sort of elegant + + align:start position:0% +incorporated that in any sort of elegant + + + align:start position:0% +incorporated that in any sort of elegant +way what's there other ways + + align:start position:0% + + + + align:start position:0% + +that's absolutely true there are other + + align:start position:0% +that's absolutely true there are other + + + align:start position:0% +that's absolutely true there are other +ways to transmit so you could transmit + + align:start position:0% +ways to transmit so you could transmit + + + align:start position:0% +ways to transmit so you could transmit +then you could reflect so we could + + align:start position:0% +then you could reflect so we could + + + align:start position:0% +then you could reflect so we could +transmit then reflect and reflect again + + align:start position:0% +transmit then reflect and reflect again + + + align:start position:0% +transmit then reflect and reflect again +and then transmit so we could transmit + + align:start position:0% +and then transmit so we could transmit + + + align:start position:0% +and then transmit so we could transmit +reflect reflect transmit + + align:start position:0% +reflect reflect transmit + + + align:start position:0% +reflect reflect transmit +what else + + align:start position:0% +what else + + + align:start position:0% +what else +do probabilities add in quantum + + align:start position:0% +do probabilities add in quantum + + + align:start position:0% +do probabilities add in quantum +mechanics + + align:start position:0% + + + + align:start position:0% + +and when you have products of events do + + align:start position:0% +and when you have products of events do + + + align:start position:0% +and when you have products of events do +your probabilities multiply + + align:start position:0% +your probabilities multiply + + + align:start position:0% +your probabilities multiply +what adds in quantum mechanics + + align:start position:0% +what adds in quantum mechanics + + + align:start position:0% +what adds in quantum mechanics +the amplitude the wave function we do + + align:start position:0% +the amplitude the wave function we do + + + align:start position:0% +the amplitude the wave function we do +not take the product of probabilities + + align:start position:0% +not take the product of probabilities + + + align:start position:0% +not take the product of probabilities +what we do is we ask what's the + + align:start position:0% +what we do is we ask what's the + + + align:start position:0% +what we do is we ask what's the +amplitude to get here from there + + align:start position:0% +amplitude to get here from there + + + align:start position:0% +amplitude to get here from there +and we take the amplitude norm squared + + align:start position:0% +and we take the amplitude norm squared + + + align:start position:0% +and we take the amplitude norm squared +to get the probability + + align:start position:0% +to get the probability + + + align:start position:0% +to get the probability +right + + align:start position:0% +right + + + align:start position:0% +right +so the correct + + align:start position:0% +so the correct + + + align:start position:0% +so the correct +question is what's the amplitude to get + + align:start position:0% +question is what's the amplitude to get + + + align:start position:0% +question is what's the amplitude to get +from here to here how does bless you how + + align:start position:0% +from here to here how does bless you how + + + align:start position:0% +from here to here how does bless you how +does the wave function of the amplitude + + align:start position:0% +does the wave function of the amplitude + + + align:start position:0% +does the wave function of the amplitude +change as you get as you move from here + + align:start position:0% +change as you get as you move from here + + + align:start position:0% +change as you get as you move from here +to here + + align:start position:0% +to here + + + align:start position:0% +to here +and for that + + align:start position:0% +and for that + + + align:start position:0% +and for that +think back to the two-slit experiment or + + align:start position:0% +think back to the two-slit experiment or + + + align:start position:0% +think back to the two-slit experiment or +think back to the boxes we asked the + + align:start position:0% +think back to the boxes we asked the + + + align:start position:0% +think back to the boxes we asked the +following question + + align:start position:0% +following question + + + align:start position:0% +following question +the transit the amplitude that you + + align:start position:0% +the transit the amplitude that you + + + align:start position:0% +the transit the amplitude that you +should transmit across this well + + align:start position:0% +should transmit across this well + + + align:start position:0% +should transmit across this well +has a bunch of + + align:start position:0% +has a bunch of + + + align:start position:0% +has a bunch of +components is a sum of a bunch of terms + + align:start position:0% +components is a sum of a bunch of terms + + + align:start position:0% +components is a sum of a bunch of terms +you could transmit down this well + + align:start position:0% +you could transmit down this well + + + align:start position:0% +you could transmit down this well +transmit down the down as well inside + + align:start position:0% +transmit down the down as well inside + + + align:start position:0% +transmit down the down as well inside +here you know your wavefunction is e to + + align:start position:0% +here you know your wavefunction is e to + + + align:start position:0% +here you know your wavefunction is e to +the i k prime l or i think i'm calling + + align:start position:0% +the i k prime l or i think i'm calling + + + align:start position:0% +the i k prime l or i think i'm calling +this k2 l + + align:start position:0% +this k2 l + + + align:start position:0% +this k2 l +uh yes key2 x + + align:start position:0% +uh yes key2 x + + + align:start position:0% +uh yes key2 x +and in moving across the well your wave + + align:start position:0% +and in moving across the well your wave + + + align:start position:0% +and in moving across the well your wave +function evolves by an e to the i k 2 l + + align:start position:0% +function evolves by an e to the i k 2 l + + + align:start position:0% +function evolves by an e to the i k 2 l +and then you could transmit again with + + align:start position:0% +and then you could transmit again with + + + align:start position:0% +and then you could transmit again with +some transmission amplitude so this + + align:start position:0% +some transmission amplitude so this + + + align:start position:0% +some transmission amplitude so this +would be the transmission down times e + + align:start position:0% +would be the transmission down times e + + + align:start position:0% +would be the transmission down times e +to the i k 2 l + + align:start position:0% +to the i k 2 l + + + align:start position:0% +to the i k 2 l +times the transmit + + align:start position:0% +times the transmit + + + align:start position:0% +times the transmit +up + + align:start position:0% +up + + + align:start position:0% +up +as we saw last time these are the same + + align:start position:0% +as we saw last time these are the same + + + align:start position:0% +as we saw last time these are the same +but i just want to keep them separate so + + align:start position:0% +but i just want to keep them separate so + + + align:start position:0% +but i just want to keep them separate so +you know which one i'm talking about so + + align:start position:0% +you know which one i'm talking about so + + + align:start position:0% +you know which one i'm talking about so +this is a contribution this is something + + align:start position:0% +this is a contribution this is something + + + align:start position:0% +this is a contribution this is something +that could contribute to the amplitude + + align:start position:0% +that could contribute to the amplitude + + + align:start position:0% +that could contribute to the amplitude +is it the only thing that could + + align:start position:0% +is it the only thing that could + + + align:start position:0% +is it the only thing that could +contribute to the amplitude no what else + + align:start position:0% +contribute to the amplitude no what else + + + align:start position:0% +contribute to the amplitude no what else +could contribute + + align:start position:0% +could contribute + + + align:start position:0% +could contribute +bounce right so to get from here to here + + align:start position:0% +bounce right so to get from here to here + + + align:start position:0% +bounce right so to get from here to here +i could transmit + + align:start position:0% +i could transmit + + + align:start position:0% +i could transmit +evolve transmit i could also transmit + + align:start position:0% +evolve transmit i could also transmit + + + align:start position:0% +evolve transmit i could also transmit +evolve + + align:start position:0% +evolve + + + align:start position:0% +evolve +reflect + + align:start position:0% +reflect + + + align:start position:0% +reflect +evolve reflect evolve transmit so + + align:start position:0% +evolve reflect evolve transmit so + + + align:start position:0% +evolve reflect evolve transmit so +there's also a term that's t + + align:start position:0% +there's also a term that's t + + + align:start position:0% +there's also a term that's t +e to the i k l + + align:start position:0% +e to the i k l + + + align:start position:0% +e to the i k l +r + + align:start position:0% +r + + + align:start position:0% +r +e to the minus i k l + + align:start position:0% + + + + align:start position:0% + +r e to the i k l + + align:start position:0% + + + + align:start position:0% + +sorry e either the plus ical because + + align:start position:0% +sorry e either the plus ical because + + + align:start position:0% +sorry e either the plus ical because +we're increasing the evolution of the + + align:start position:0% +we're increasing the evolution of the + + + align:start position:0% +we're increasing the evolution of the +phase um and then transmit finally at + + align:start position:0% +phase um and then transmit finally at + + + align:start position:0% +phase um and then transmit finally at +the end + + align:start position:0% + + + + align:start position:0% + +and these k's are all k2s k2 p2 but i + + align:start position:0% +and these k's are all k2s k2 p2 but i + + + align:start position:0% +and these k's are all k2s k2 p2 but i +could have done that many times + + align:start position:0% + + + + align:start position:0% + +but notice that each time what i'm going + + align:start position:0% +but notice that each time what i'm going + + + align:start position:0% +but notice that each time what i'm going +to do is i'm going to + + align:start position:0% +to do is i'm going to + + + align:start position:0% +to do is i'm going to +transmit reflect reflect transmit or + + align:start position:0% +transmit reflect reflect transmit or + + + align:start position:0% +transmit reflect reflect transmit or +transmit reflect reflect reflect reflect + + align:start position:0% +transmit reflect reflect reflect reflect + + + align:start position:0% +transmit reflect reflect reflect reflect +transmit so i'm always going to do this + + align:start position:0% + + + + align:start position:0% + +some even number of some number of times + + align:start position:0% +some even number of some number of times + + + align:start position:0% +some even number of some number of times +i do this once i do this twice i do it + + align:start position:0% +i do this once i do this twice i do it + + + align:start position:0% +i do this once i do this twice i do it +thrice this gives me a geometric series + + align:start position:0% +thrice this gives me a geometric series + + + align:start position:0% +thrice this gives me a geometric series +this is t + + align:start position:0% +this is t + + + align:start position:0% +this is t +e to the i k 2 x + + align:start position:0% +e to the i k 2 x + + + align:start position:0% +e to the i k 2 x +t + + align:start position:0% +t + + + align:start position:0% +t +times + + align:start position:0% +times + + + align:start position:0% +times +1 plus + + align:start position:0% +1 plus + + + align:start position:0% +1 plus +this quantity plus this quantity squared + + align:start position:0% +this quantity plus this quantity squared + + + align:start position:0% +this quantity plus this quantity squared +that's a geometric series 1 over 1 plus + + align:start position:0% +that's a geometric series 1 over 1 plus + + + align:start position:0% +that's a geometric series 1 over 1 plus +this quantity squared + + align:start position:0% + + + + align:start position:0% + +or sorry 1 minus because it's a + + align:start position:0% +or sorry 1 minus because it's a + + + align:start position:0% +or sorry 1 minus because it's a +geometric sum and what is this quantity + + align:start position:0% +geometric sum and what is this quantity + + + align:start position:0% +geometric sum and what is this quantity +well it's r squared and remember the r's + + align:start position:0% +well it's r squared and remember the r's + + + align:start position:0% +well it's r squared and remember the r's +in both directions are the same so i'm + + align:start position:0% +in both directions are the same so i'm + + + align:start position:0% +in both directions are the same so i'm +just going to write it as r squared + + align:start position:0% +just going to write it as r squared + + + align:start position:0% +just going to write it as r squared +e to the 2i + + align:start position:0% + + + + align:start position:0% + +well + + align:start position:0% +well + + + align:start position:0% +well +r squared it's a real number but i'm + + align:start position:0% +r squared it's a real number but i'm + + + align:start position:0% +r squared it's a real number but i'm +going to put the + + align:start position:0% +going to put the + + + align:start position:0% +going to put the +abs on absolute value on anyway it's + + align:start position:0% +abs on absolute value on anyway it's + + + align:start position:0% +abs on absolute value on anyway it's +going to simplify my life you need the + + align:start position:0% +going to simplify my life you need the + + + align:start position:0% +going to simplify my life you need the +2i k2l + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so this is our prediction from multiple + + align:start position:0% +so this is our prediction from multiple + + + align:start position:0% +so this is our prediction from multiple +bounces + + align:start position:0% +bounces + + + align:start position:0% +bounces +what we're doing here is we're taking + + align:start position:0% +what we're doing here is we're taking + + + align:start position:0% +what we're doing here is we're taking +seriously the superposition principle + + align:start position:0% +seriously the superposition principle + + + align:start position:0% +seriously the superposition principle +that says given any process any way that + + align:start position:0% +that says given any process any way that + + + align:start position:0% +that says given any process any way that +that process could happen you sum up the + + align:start position:0% +that process could happen you sum up the + + + align:start position:0% +that process could happen you sum up the +amplitudes and the probability is the + + align:start position:0% +amplitudes and the probability is the + + + align:start position:0% +amplitudes and the probability is the +norm squared if we have a source and we + + align:start position:0% +norm squared if we have a source and we + + + align:start position:0% +norm squared if we have a source and we +have two slits + + align:start position:0% +have two slits + + + align:start position:0% +have two slits +and i ask you what's the probability + + align:start position:0% +and i ask you what's the probability + + + align:start position:0% +and i ask you what's the probability +that you land here the probability is + + align:start position:0% +that you land here the probability is + + + align:start position:0% +that you land here the probability is +not the sum of the probabilities for + + align:start position:0% +not the sum of the probabilities for + + + align:start position:0% +not the sum of the probabilities for +each individual transit the probability + + align:start position:0% +each individual transit the probability + + + align:start position:0% +each individual transit the probability +is the square of the amplitude where the + + align:start position:0% +is the square of the amplitude where the + + + align:start position:0% +is the square of the amplitude where the +amplitude is the sum amplitude top plus + + align:start position:0% +amplitude is the sum amplitude top plus + + + align:start position:0% +amplitude is the sum amplitude top plus +amplitude bottom + + align:start position:0% +amplitude bottom + + + align:start position:0% +amplitude bottom +here there are many many slits there are + + align:start position:0% +here there are many many slits there are + + + align:start position:0% +here there are many many slits there are +many different ways this could happen + + align:start position:0% +many different ways this could happen + + + align:start position:0% +many different ways this could happen +you could reflect multiple times + + align:start position:0% +you could reflect multiple times + + + align:start position:0% +you could reflect multiple times +ever cool with that + + align:start position:0% +ever cool with that + + + align:start position:0% +ever cool with that +no by the same token we could have done + + align:start position:0% +no by the same token we could have done + + + align:start position:0% +no by the same token we could have done +the same thing for reflection but let's + + align:start position:0% +the same thing for reflection but let's + + + align:start position:0% +the same thing for reflection but let's +stick with transmission for the moment + + align:start position:0% +stick with transmission for the moment + + + align:start position:0% +stick with transmission for the moment +this is what we get for the transmission + + align:start position:0% +this is what we get for the transmission + + + align:start position:0% +this is what we get for the transmission +and again the transmission amplitudes + + align:start position:0% +and again the transmission amplitudes + + + align:start position:0% +and again the transmission amplitudes +across the step as we saw last time are + + align:start position:0% +across the step as we saw last time are + + + align:start position:0% +across the step as we saw last time are +the same so this is in fact t squared + + align:start position:0% + + + + align:start position:0% + +and this gives us + + align:start position:0% +and this gives us + + + align:start position:0% +and this gives us +a result + + align:start position:0% +a result + + + align:start position:0% +a result +for transmission down the potential well + + align:start position:0% +for transmission down the potential well + + + align:start position:0% +for transmission down the potential well +and + + align:start position:0% +and + + + align:start position:0% +and +if we put in the factors of if we use + + align:start position:0% +if we put in the factors of if we use + + + align:start position:0% +if we put in the factors of if we use +what uh the trench sorry if we use what + + align:start position:0% +what uh the trench sorry if we use what + + + align:start position:0% +what uh the trench sorry if we use what +the reflection + + align:start position:0% +the reflection + + + align:start position:0% +the reflection +and transmission + + align:start position:0% +and transmission + + + align:start position:0% +and transmission +amplitudes were + + align:start position:0% +amplitudes were + + + align:start position:0% +amplitudes were +for our stepwells the answer that this + + align:start position:0% +for our stepwells the answer that this + + + align:start position:0% +for our stepwells the answer that this +gives is 1 over + + align:start position:0% +gives is 1 over + + + align:start position:0% +gives is 1 over +e to the i k2l + + align:start position:0% +e to the i k2l + + + align:start position:0% +e to the i k2l +minus 2i upon the transmission + + align:start position:0% +minus 2i upon the transmission + + + align:start position:0% +minus 2i upon the transmission +for a step + + align:start position:0% +for a step + + + align:start position:0% +for a step +times + + align:start position:0% +times + + + align:start position:0% +times +sine of k prime l or sorry k2l + + align:start position:0% +sine of k prime l or sorry k2l + + + align:start position:0% +sine of k prime l or sorry k2l +now this isn't the same + + align:start position:0% +now this isn't the same + + + align:start position:0% +now this isn't the same +as the + + align:start position:0% +as the + + + align:start position:0% +as the +probability that we derived over here + + align:start position:0% +probability that we derived over here + + + align:start position:0% +probability that we derived over here +but that's because this isn't the + + align:start position:0% +but that's because this isn't the + + + align:start position:0% +but that's because this isn't the +probability this was the amplitude we + + align:start position:0% +probability this was the amplitude we + + + align:start position:0% +probability this was the amplitude we +just computed the total amplitude to get + + align:start position:0% +just computed the total amplitude to get + + + align:start position:0% +just computed the total amplitude to get +the probability we have to take the norm + + align:start position:0% +the probability we have to take the norm + + + align:start position:0% +the probability we have to take the norm +squared of the amplitude + + align:start position:0% +squared of the amplitude + + + align:start position:0% +squared of the amplitude +and when we take the norm squared + + align:start position:0% +and when we take the norm squared + + + align:start position:0% +and when we take the norm squared +what we get is 1 upon 1 plus 1 over 4 + + align:start position:0% +what we get is 1 upon 1 plus 1 over 4 + + + align:start position:0% +what we get is 1 upon 1 plus 1 over 4 +epsilon epsilon minus 1 or plus 1. + + align:start position:0% +epsilon epsilon minus 1 or plus 1. + + + align:start position:0% +epsilon epsilon minus 1 or plus 1. +sine squared + + align:start position:0% +sine squared + + + align:start position:0% +sine squared +of g naught + + align:start position:0% +of g naught + + + align:start position:0% +of g naught +root epsilon plus one + + align:start position:0% + + + + align:start position:0% + +we get the same answer + + align:start position:0% + + + + align:start position:0% + +sorry + + align:start position:0% + + + + align:start position:0% + +this is inequality + + align:start position:0% +this is inequality + + + align:start position:0% +this is inequality +oh sorry sorry + + align:start position:0% +oh sorry sorry + + + align:start position:0% +oh sorry sorry +sorry + + align:start position:0% +sorry + + + align:start position:0% +sorry +thank you martin + + align:start position:0% +thank you martin + + + align:start position:0% +thank you martin +we get that the transmission probability + + align:start position:0% +we get that the transmission probability + + + align:start position:0% +we get that the transmission probability +when we take the norm square of the + + align:start position:0% +when we take the norm square of the + + + align:start position:0% +when we take the norm square of the +amplitude thank you is equal to this + + align:start position:0% +amplitude thank you is equal to this + + + align:start position:0% +amplitude thank you is equal to this +which is the same as we got before + + align:start position:0% +which is the same as we got before + + + align:start position:0% +which is the same as we got before +thanks + + align:start position:0% +thanks + + + align:start position:0% +thanks +okay so this is to me this is very sad + + align:start position:0% +okay so this is to me this is very sad + + + align:start position:0% +okay so this is to me this is very sad +yeah please + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% +um + + + align:start position:0% +um +kl equals pi doesn't work it does you + + align:start position:0% +kl equals pi doesn't work it does you + + + align:start position:0% +kl equals pi doesn't work it does you +just have to be careful what kl + + align:start position:0% +just have to be careful what kl + + + align:start position:0% +just have to be careful what kl +expressing it sorry + + align:start position:0% +expressing it sorry + + + align:start position:0% +expressing it sorry +what am i + + align:start position:0% +what am i + + + align:start position:0% +what am i +um + + align:start position:0% + + + + align:start position:0% + +because i'm an idiot because i got a + + align:start position:0% +because i'm an idiot because i got a + + + align:start position:0% +because i'm an idiot because i got a +factor of two wrong thank you + + align:start position:0% + + + + align:start position:0% + +thank you matt + + align:start position:0% +thank you matt + + + align:start position:0% +thank you matt +thank you + + align:start position:0% +thank you + + + align:start position:0% +thank you +um + + align:start position:0% +um + + + align:start position:0% +um +answer analysis it's a wonderful thing + + align:start position:0% +answer analysis it's a wonderful thing + + + align:start position:0% +answer analysis it's a wonderful thing +um + + align:start position:0% +um + + + align:start position:0% +um +okay + + align:start position:0% + + + + align:start position:0% + +so this gives us this has something + + align:start position:0% +so this gives us this has something + + + align:start position:0% +so this gives us this has something +really nice for us + + align:start position:0% +really nice for us + + + align:start position:0% +really nice for us +why are we getting a resonance at + + align:start position:0% +why are we getting a resonance at + + + align:start position:0% +why are we getting a resonance at +special values + + align:start position:0% +special values + + + align:start position:0% +special values +why are we getting a resonance of + + align:start position:0% +why are we getting a resonance of + + + align:start position:0% +why are we getting a resonance of +special values of the energy + + align:start position:0% +special values of the energy + + + align:start position:0% +special values of the energy +what's happening + + align:start position:0% +what's happening + + + align:start position:0% +what's happening +well in this process in this quantum + + align:start position:0% +well in this process in this quantum + + + align:start position:0% +well in this process in this quantum +mechanical process + + align:start position:0% +mechanical process + + + align:start position:0% +mechanical process +of multiple interactions multiple + + align:start position:0% +of multiple interactions multiple + + + align:start position:0% +of multiple interactions multiple +scatterings there are many terms in the + + align:start position:0% +scatterings there are many terms in the + + + align:start position:0% +scatterings there are many terms in the +amplitude for transmitting + + align:start position:0% +amplitude for transmitting + + + align:start position:0% +amplitude for transmitting +there are terms that involve no + + align:start position:0% +there are terms that involve no + + + align:start position:0% +there are terms that involve no +reflection there are terms that involve + + align:start position:0% +reflection there are terms that involve + + + align:start position:0% +reflection there are terms that involve +two reflections they're terms that + + align:start position:0% +two reflections they're terms that + + + align:start position:0% +two reflections they're terms that +involve four reflections + + align:start position:0% +involve four reflections + + + align:start position:0% +involve four reflections +and they all come with an actual + + align:start position:0% +and they all come with an actual + + + align:start position:0% +and they all come with an actual +magnitude and a phase + + align:start position:0% +magnitude and a phase + + + align:start position:0% +magnitude and a phase +and when the phase + + align:start position:0% +and when the phase + + + align:start position:0% +and when the phase +is the same + + align:start position:0% +is the same + + + align:start position:0% +is the same +they add constructively + + align:start position:0% +they add constructively + + + align:start position:0% +they add constructively +and when the phases are not the same + + align:start position:0% +and when the phases are not the same + + + align:start position:0% +and when the phases are not the same +they interfere and when the phases are + + align:start position:0% +they interfere and when the phases are + + + align:start position:0% +they interfere and when the phases are +exactly off they interfere destructively + + align:start position:0% +exactly off they interfere destructively + + + align:start position:0% +exactly off they interfere destructively +and that is why you're getting a + + align:start position:0% +and that is why you're getting a + + + align:start position:0% +and that is why you're getting a +resonance + + align:start position:0% +resonance + + + align:start position:0% +resonance +multiple terms in your superposition + + align:start position:0% +multiple terms in your superposition + + + align:start position:0% +multiple terms in your superposition +interfere with each other something that + + align:start position:0% +interfere with each other something that + + + align:start position:0% +interfere with each other something that +does not happen classically classically + + align:start position:0% +does not happen classically classically + + + align:start position:0% +does not happen classically classically +the probabilities are products quantum + + align:start position:0% +the probabilities are products quantum + + + align:start position:0% +the probabilities are products quantum +mechanically we have superposition and + + align:start position:0% +mechanically we have superposition and + + + align:start position:0% +mechanically we have superposition and +probabilities are the squares of the + + align:start position:0% +probabilities are the squares of the + + + align:start position:0% +probabilities are the squares of the +amplitude and we get interference + + align:start position:0% +amplitude and we get interference + + + align:start position:0% +amplitude and we get interference +effects and the probabilities + + align:start position:0% +effects and the probabilities + + + align:start position:0% +effects and the probabilities +cool + + align:start position:0% +cool + + + align:start position:0% +cool +so to me this is a nice + + align:start position:0% +so to me this is a nice + + + align:start position:0% +so to me this is a nice +sort of glorious version of the two-slit + + align:start position:0% +sort of glorious version of the two-slit + + + align:start position:0% +sort of glorious version of the two-slit +experiment um and we're gonna bump up + + align:start position:0% +experiment um and we're gonna bump up + + + align:start position:0% +experiment um and we're gonna bump up +again into it later when we talk about + + align:start position:0% +again into it later when we talk about + + + align:start position:0% +again into it later when we talk about +the physics of solids uh + + align:start position:0% +the physics of solids uh + + + align:start position:0% +the physics of solids uh +in the real world + + align:start position:0% +in the real world + + + align:start position:0% +in the real world +okay + + align:start position:0% +okay + + + align:start position:0% +okay +questions at this point + + align:start position:0% +questions at this point + + + align:start position:0% +questions at this point +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +you said earlier + + align:start position:0% + + + + align:start position:0% + +yeah what's special about that so what's + + align:start position:0% +yeah what's special about that so what's + + + align:start position:0% +yeah what's special about that so what's +special about that is so at this point + + align:start position:0% +special about that is so at this point + + + align:start position:0% +special about that is so at this point +where kale is in pi + + align:start position:0% +where kale is in pi + + + align:start position:0% +where kale is in pi +when kale is is n pi we get perfect + + align:start position:0% +when kale is is n pi we get perfect + + + align:start position:0% +when kale is is n pi we get perfect +transmission + + align:start position:0% +transmission + + + align:start position:0% +transmission +when kl is equal to n plus one half pi + + align:start position:0% +when kl is equal to n plus one half pi + + + align:start position:0% +when kl is equal to n plus one half pi +the reflection is as good as it gets + + align:start position:0% +the reflection is as good as it gets + + + align:start position:0% +the reflection is as good as it gets +okay so what that's really doing is it's + + align:start position:0% +okay so what that's really doing is it's + + + align:start position:0% +okay so what that's really doing is it's +saying when is this largest + + align:start position:0% +saying when is this largest + + + align:start position:0% +saying when is this largest +locally largest okay so that's these + + align:start position:0% +locally largest okay so that's these + + + align:start position:0% +locally largest okay so that's these +special points when we're the + + align:start position:0% +special points when we're the + + + align:start position:0% +special points when we're the +transmission is as small as possible + + align:start position:0% +transmission is as small as possible + + + align:start position:0% +transmission is as small as possible +which means the reflection which is one + + align:start position:0% +which means the reflection which is one + + + align:start position:0% +which means the reflection which is one +minus the transmission probabilities as + + align:start position:0% +minus the transmission probabilities as + + + align:start position:0% +minus the transmission probabilities as +large as possible + + align:start position:0% +large as possible + + + align:start position:0% +large as possible +and you can get that again from from + + align:start position:0% +and you can get that again from from + + + align:start position:0% +and you can get that again from from +these expressions + + align:start position:0% +these expressions + + + align:start position:0% +these expressions +other questions + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +stopping + + align:start position:0% +stopping + + + align:start position:0% +stopping +so i want to think a little more about + + align:start position:0% +so i want to think a little more about + + + align:start position:0% +so i want to think a little more about +these square barriers and in particular + + align:start position:0% +these square barriers and in particular + + + align:start position:0% +these square barriers and in particular +in thinking about the square well + + align:start position:0% +in thinking about the square well + + + align:start position:0% +in thinking about the square well +barrier + + align:start position:0% +barrier + + + align:start position:0% +barrier +what we've been talking about all along + + align:start position:0% +what we've been talking about all along + + + align:start position:0% +what we've been talking about all along +are monochromatic + + align:start position:0% +are monochromatic + + + align:start position:0% +are monochromatic +wave packers we've been talking about + + align:start position:0% +wave packers we've been talking about + + + align:start position:0% +wave packers we've been talking about +plane waves just simple e to the ikx + + align:start position:0% +plane waves just simple e to the ikx + + + align:start position:0% +plane waves just simple e to the ikx +but you can't actually build + + align:start position:0% +but you can't actually build + + + align:start position:0% +but you can't actually build +uh you can't put a single particle in a + + align:start position:0% +uh you can't put a single particle in a + + + align:start position:0% +uh you can't put a single particle in a +state + + align:start position:0% +state + + + align:start position:0% +state +which is + + align:start position:0% +which is + + + align:start position:0% +which is +a plane wave right it's not normalizable + + align:start position:0% +a plane wave right it's not normalizable + + + align:start position:0% +a plane wave right it's not normalizable +what we really mean at the end of the + + align:start position:0% +what we really mean at the end of the + + + align:start position:0% +what we really mean at the end of the +day when we talk about single particles + + align:start position:0% +day when we talk about single particles + + + align:start position:0% +day when we talk about single particles +is we put them in some well localized + + align:start position:0% +is we put them in some well localized + + + align:start position:0% +is we put them in some well localized +wave packet + + align:start position:0% +wave packet + + + align:start position:0% +wave packet +which at time zero let's say is at + + align:start position:0% +which at time zero let's say is at + + + align:start position:0% +which at time zero let's say is at +position x naught or maybe + + align:start position:0% +position x naught or maybe + + + align:start position:0% +position x naught or maybe +well x naught which in this case is + + align:start position:0% +well x naught which in this case is + + + align:start position:0% +well x naught which in this case is +negative and which has some + + align:start position:0% +negative and which has some + + + align:start position:0% +negative and which has some +well-defined average momentum cannot + + align:start position:0% +well-defined average momentum cannot + + + align:start position:0% +well-defined average momentum cannot +i'll say it's the expectation value of + + align:start position:0% +i'll say it's the expectation value of + + + align:start position:0% +i'll say it's the expectation value of +momentum in this wave package + + align:start position:0% +momentum in this wave package + + + align:start position:0% +momentum in this wave package +and the question we really want to ask + + align:start position:0% +and the question we really want to ask + + + align:start position:0% +and the question we really want to ask +when we talk about scattering is what + + align:start position:0% +when we talk about scattering is what + + + align:start position:0% +when we talk about scattering is what +happens to this beast as it + + align:start position:0% +happens to this beast as it + + + align:start position:0% +happens to this beast as it +hits the weight as it hits the barrier + + align:start position:0% +hits the weight as it hits the barrier + + + align:start position:0% +hits the weight as it hits the barrier +which i'm going to put the left-hand + + align:start position:0% +which i'm going to put the left-hand + + + align:start position:0% +which i'm going to put the left-hand +side at zero on the right-hand side at l + + align:start position:0% +side at zero on the right-hand side at l + + + align:start position:0% +side at zero on the right-hand side at l +and let the depth be minus v-naught + + align:start position:0% +and let the depth be minus v-naught + + + align:start position:0% +and let the depth be minus v-naught +again + + align:start position:0% +again + + + align:start position:0% +again +what happens is this incident wave + + align:start position:0% +what happens is this incident wave + + + align:start position:0% +what happens is this incident wave +packet hits the barrier + + align:start position:0% +packet hits the barrier + + + align:start position:0% +packet hits the barrier +and then scatters off + + align:start position:0% +and then scatters off + + + align:start position:0% +and then scatters off +well we know what would happen if it was + + align:start position:0% +well we know what would happen if it was + + + align:start position:0% +well we know what would happen if it was +a plane wave but a plane wave wouldn't + + align:start position:0% +a plane wave but a plane wave wouldn't + + + align:start position:0% +a plane wave but a plane wave wouldn't +be localized so this is the question i + + align:start position:0% +be localized so this is the question i + + + align:start position:0% +be localized so this is the question i +want to ask and i want to use the + + align:start position:0% +want to ask and i want to use the + + + align:start position:0% +want to ask and i want to use the +results we already have + + align:start position:0% +results we already have + + + align:start position:0% +results we already have +now here's the key thing + + align:start position:0% + + + + align:start position:0% + +if we had consider for to begin with + + align:start position:0% +if we had consider for to begin with + + + align:start position:0% +if we had consider for to begin with +just a wave packet + + align:start position:0% +just a wave packet + + + align:start position:0% +just a wave packet +for a free particle centered at x naught + + align:start position:0% +for a free particle centered at x naught + + + align:start position:0% +for a free particle centered at x naught +and with momentum k naught + + align:start position:0% +and with momentum k naught + + + align:start position:0% +and with momentum k naught +okay + + align:start position:0% +okay + + + align:start position:0% +okay +just for a free particle + + align:start position:0% +just for a free particle + + + align:start position:0% +just for a free particle +we know how to write this and if this is + + align:start position:0% +we know how to write this and if this is + + + align:start position:0% +we know how to write this and if this is +um + + align:start position:0% +um + + + align:start position:0% +um +we can put the system for example we can + + align:start position:0% +we can put the system for example we can + + + align:start position:0% +we can put the system for example we can +take our wave function at time 0 to be + + align:start position:0% +take our wave function at time 0 to be + + + align:start position:0% +take our wave function at time 0 to be +a gaussian some normalization times e to + + align:start position:0% +a gaussian some normalization times e to + + + align:start position:0% +a gaussian some normalization times e to +the minus x minus x naught + + align:start position:0% +the minus x minus x naught + + + align:start position:0% +the minus x minus x naught +squared + + align:start position:0% +squared + + + align:start position:0% +squared +over 2a squared + + align:start position:0% +over 2a squared + + + align:start position:0% +over 2a squared +and we want to give it some momentum k + + align:start position:0% +and we want to give it some momentum k + + + align:start position:0% +and we want to give it some momentum k +naught and you know how to do that after + + align:start position:0% +naught and you know how to do that after + + + align:start position:0% +naught and you know how to do that after +the last problem set e to the i k naught + + align:start position:0% +the last problem set e to the i k naught + + + align:start position:0% +the last problem set e to the i k naught +x + + align:start position:0% +x + + + align:start position:0% +x +everyone call that + + align:start position:0% +everyone call that + + + align:start position:0% +everyone call that +so there's our initial wave function + + align:start position:0% + + + + align:start position:0% + +and we want to know how it evolves with + + align:start position:0% +and we want to know how it evolves with + + + align:start position:0% +and we want to know how it evolves with +time and we know how to do that to + + align:start position:0% +time and we know how to do that to + + + align:start position:0% +time and we know how to do that to +evolve in time we first expand it in + + align:start position:0% +evolve in time we first expand it in + + + align:start position:0% +evolve in time we first expand it in +energy eigenstates + + align:start position:0% +energy eigenstates + + + align:start position:0% +energy eigenstates +so psi + + align:start position:0% +so psi + + + align:start position:0% +so psi +of x naught + + align:start position:0% +of x naught + + + align:start position:0% +of x naught +is equal to well the energy i can states + + align:start position:0% +is equal to well the energy i can states + + + align:start position:0% +is equal to well the energy i can states +in this case are plane waves dk + + align:start position:0% +in this case are plane waves dk + + + align:start position:0% +in this case are plane waves dk +e to the ikx + + align:start position:0% +e to the ikx + + + align:start position:0% +e to the ikx +over root 2 pi + + align:start position:0% +over root 2 pi + + + align:start position:0% +over root 2 pi +times some coefficients f of k the + + align:start position:0% +times some coefficients f of k the + + + align:start position:0% +times some coefficients f of k the +expansion coefficients but these are + + align:start position:0% +expansion coefficients but these are + + + align:start position:0% +expansion coefficients but these are +just the fourier transform + + align:start position:0% +just the fourier transform + + + align:start position:0% +just the fourier transform +of + + align:start position:0% +of + + + align:start position:0% +of +our initial gaussian wave packet and we + + align:start position:0% +our initial gaussian wave packet and we + + + align:start position:0% +our initial gaussian wave packet and we +know what the form of f 0 is f 0 or + + align:start position:0% +know what the form of f 0 is f 0 or + + + align:start position:0% +know what the form of f 0 is f 0 or +sorry f + + align:start position:0% +sorry f + + + align:start position:0% +sorry f +of k + + align:start position:0% +of k + + + align:start position:0% +of k +is equal to well it's a gaussian of + + align:start position:0% +is equal to well it's a gaussian of + + + align:start position:0% +is equal to well it's a gaussian of +width 1 upon alpha + + align:start position:0% +width 1 upon alpha + + + align:start position:0% +width 1 upon alpha +e to the minus + + align:start position:0% +e to the minus + + + align:start position:0% +e to the minus +k minus k naught because it has momentum + + align:start position:0% +k minus k naught because it has momentum + + + align:start position:0% +k minus k naught because it has momentum +k naught so it's centered around k + + align:start position:0% +k naught so it's centered around k + + + align:start position:0% +k naught so it's centered around k +naught squared over 2 times a squared + + align:start position:0% +naught squared over 2 times a squared + + + align:start position:0% +naught squared over 2 times a squared +and the a goes upstairs + + align:start position:0% +and the a goes upstairs + + + align:start position:0% +and the a goes upstairs +and the position + + align:start position:0% +and the position + + + align:start position:0% +and the position +of the fourier of the uh the initial + + align:start position:0% +of the fourier of the uh the initial + + + align:start position:0% +of the fourier of the uh the initial +wave packet is encoded in the fourier + + align:start position:0% +wave packet is encoded in the fourier + + + align:start position:0% +wave packet is encoded in the fourier +transform and i'm going to put a + + align:start position:0% +transform and i'm going to put a + + + align:start position:0% +transform and i'm going to put a +normalization here which i'm not going + + align:start position:0% +normalization here which i'm not going + + + align:start position:0% +normalization here which i'm not going +to worry about + + align:start position:0% +to worry about + + + align:start position:0% +to worry about +with an overall phase e to the i um + + align:start position:0% +with an overall phase e to the i um + + + align:start position:0% +with an overall phase e to the i um +minus i + + align:start position:0% +minus i + + + align:start position:0% +minus i +k x naught + + align:start position:0% +k x naught + + + align:start position:0% +k x naught +so in just the same way that adding on a + + align:start position:0% +so in just the same way that adding on a + + + align:start position:0% +so in just the same way that adding on a +phase e to the aik not x in the position + + align:start position:0% +phase e to the aik not x in the position + + + align:start position:0% +phase e to the aik not x in the position +space wave function tells you what the + + align:start position:0% +space wave function tells you what the + + + align:start position:0% +space wave function tells you what the +expectation value of momentum is tacking + + align:start position:0% +expectation value of momentum is tacking + + + align:start position:0% +expectation value of momentum is tacking +on the phase and we can get this from + + align:start position:0% +on the phase and we can get this from + + + align:start position:0% +on the phase and we can get this from +just fourier transform attacking on the + + align:start position:0% +just fourier transform attacking on the + + + align:start position:0% +just fourier transform attacking on the +phase e to the ik x naught tells you in + + align:start position:0% +phase e to the ik x naught tells you in + + + align:start position:0% +phase e to the ik x naught tells you in +the fourier transform tells you the + + align:start position:0% +the fourier transform tells you the + + + align:start position:0% +the fourier transform tells you the +center point the central position of the + + align:start position:0% +center point the central position of the + + + align:start position:0% +center point the central position of the +wave pack okay so this you did on the + + align:start position:0% +wave pack okay so this you did on the + + + align:start position:0% +wave pack okay so this you did on the +problem set and this is a trivial + + align:start position:0% +problem set and this is a trivial + + + align:start position:0% +problem set and this is a trivial +momentum space version of the same thing + + align:start position:0% +momentum space version of the same thing + + + align:start position:0% +momentum space version of the same thing +so here's our wave packet expanded in + + align:start position:0% +so here's our wave packet expanded in + + + align:start position:0% +so here's our wave packet expanded in +plane waves which are energy eigenstates + + align:start position:0% +plane waves which are energy eigenstates + + + align:start position:0% +plane waves which are energy eigenstates +and the statement that these are energy + + align:start position:0% +and the statement that these are energy + + + align:start position:0% +and the statement that these are energy +eigenstates is equivalent to the + + align:start position:0% +eigenstates is equivalent to the + + + align:start position:0% +eigenstates is equivalent to the +statement that under time evolution they + + align:start position:0% +statement that under time evolution they + + + align:start position:0% +statement that under time evolution they +do nothing but rotate by a phase + + align:start position:0% +do nothing but rotate by a phase + + + align:start position:0% +do nothing but rotate by a phase +so if we want to know what the wave + + align:start position:0% +so if we want to know what the wave + + + align:start position:0% +so if we want to know what the wave +function is a function of time psi of x + + align:start position:0% +function is a function of time psi of x + + + align:start position:0% +function is a function of time psi of x +and t + + align:start position:0% +and t + + + align:start position:0% +and t +is equal to the integral dk + + align:start position:0% +is equal to the integral dk + + + align:start position:0% +is equal to the integral dk +the fourier mode + + align:start position:0% +the fourier mode + + + align:start position:0% +the fourier mode +uh f of k + + align:start position:0% +uh f of k + + + align:start position:0% +uh f of k +i'll write it out + + align:start position:0% +i'll write it out + + + align:start position:0% +i'll write it out +actually i'm going to write this out + + align:start position:0% +actually i'm going to write this out + + + align:start position:0% +actually i'm going to write this out +explicitly f of k + + align:start position:0% +explicitly f of k + + + align:start position:0% +explicitly f of k +1 over root 2 pi + + align:start position:0% +1 over root 2 pi + + + align:start position:0% +1 over root 2 pi +e to the i k x minus omega t + + align:start position:0% +e to the i k x minus omega t + + + align:start position:0% +e to the i k x minus omega t +where omega of course is a function of k + + align:start position:0% +where omega of course is a function of k + + + align:start position:0% +where omega of course is a function of k +it's a free particle so for our free + + align:start position:0% +it's a free particle so for our free + + + align:start position:0% +it's a free particle so for our free +particle uh h bar squared omega squared + + align:start position:0% +particle uh h bar squared omega squared + + + align:start position:0% +particle uh h bar squared omega squared +oh sorry h bar squared k squared + + align:start position:0% +oh sorry h bar squared k squared + + + align:start position:0% +oh sorry h bar squared k squared +upon 2m + + align:start position:0% +upon 2m + + + align:start position:0% +upon 2m +is equal to uh h bar omega + + align:start position:0% +is equal to uh h bar omega + + + align:start position:0% +is equal to uh h bar omega +okay so this is we've done this before + + align:start position:0% +okay so this is we've done this before + + + align:start position:0% +okay so this is we've done this before +but now what i want to do is i'm going + + align:start position:0% +but now what i want to do is i'm going + + + align:start position:0% +but now what i want to do is i'm going +to take exactly the same system and i + + align:start position:0% +to take exactly the same system and i + + + align:start position:0% +to take exactly the same system and i +want to add at position 0 a well of + + align:start position:0% +want to add at position 0 a well of + + + align:start position:0% +want to add at position 0 a well of +depth v naught and width l + + align:start position:0% + + + + align:start position:0% + +how is our story going to change + + align:start position:0% + + + + align:start position:0% + +well we want our initial wave packet + + align:start position:0% +well we want our initial wave packet + + + align:start position:0% +well we want our initial wave packet +which is you know up to us to choose we + + align:start position:0% +which is you know up to us to choose we + + + align:start position:0% +which is you know up to us to choose we +want our initial wave packet to be the + + align:start position:0% +want our initial wave packet to be the + + + align:start position:0% +want our initial wave packet to be the +same we want to start with the gaussian + + align:start position:0% +same we want to start with the gaussian + + + align:start position:0% +same we want to start with the gaussian +far far far away from the barrier + + align:start position:0% +far far far away from the barrier + + + align:start position:0% +far far far away from the barrier +we want it to be well localized in + + align:start position:0% +we want it to be well localized in + + + align:start position:0% +we want it to be well localized in +position and well localized in momentum + + align:start position:0% +position and well localized in momentum + + + align:start position:0% +position and well localized in momentum +space not perfectly localized of course + + align:start position:0% +space not perfectly localized of course + + + align:start position:0% +space not perfectly localized of course +it's a finite gaussian to satisfy the + + align:start position:0% +it's a finite gaussian to satisfy the + + + align:start position:0% +it's a finite gaussian to satisfy the +uncertainty principle but it's well + + align:start position:0% +uncertainty principle but it's well + + + align:start position:0% +uncertainty principle but it's well +localized so how does the story change + + align:start position:0% +localized so how does the story change + + + align:start position:0% +localized so how does the story change +well this doesn't change at all it's the + + align:start position:0% +well this doesn't change at all it's the + + + align:start position:0% +well this doesn't change at all it's the +same wave function + + align:start position:0% +same wave function + + + align:start position:0% +same wave function +however when we expand in energy + + align:start position:0% +however when we expand in energy + + + align:start position:0% +however when we expand in energy +eigenstates the energy eigenstates are + + align:start position:0% +eigenstates the energy eigenstates are + + + align:start position:0% +eigenstates the energy eigenstates are +no longer + + align:start position:0% +no longer + + + align:start position:0% +no longer +the energy eigenstates are no longer + + align:start position:0% +the energy eigenstates are no longer + + + align:start position:0% +the energy eigenstates are no longer +simple plane waves + + align:start position:0% +simple plane waves + + + align:start position:0% +simple plane waves +the energy eigen states as we know + + align:start position:0% +the energy eigen states as we know + + + align:start position:0% +the energy eigen states as we know +for the system take a different form + + align:start position:0% +for the system take a different form + + + align:start position:0% +for the system take a different form +for the square well + + align:start position:0% +for the square well + + + align:start position:0% +for the square well +and positive energy scattering states + + align:start position:0% +and positive energy scattering states + + + align:start position:0% +and positive energy scattering states +the plane wave or the energy eigenstates + + align:start position:0% +the plane wave or the energy eigenstates + + + align:start position:0% +the plane wave or the energy eigenstates +which i will label by k + + align:start position:0% +which i will label by k + + + align:start position:0% +which i will label by k +just because i'm going to call e is + + align:start position:0% +just because i'm going to call e is + + + align:start position:0% +just because i'm going to call e is +equal to h bar squared k squared upon 2 + + align:start position:0% +equal to h bar squared k squared upon 2 + + + align:start position:0% +equal to h bar squared k squared upon 2 +m + + align:start position:0% +m + + + align:start position:0% +m +which is the energy + + align:start position:0% +which is the energy + + + align:start position:0% +which is the energy +well the energy is constant which is the + + align:start position:0% +well the energy is constant which is the + + + align:start position:0% +well the energy is constant which is the +k asymptotically far away from the + + align:start position:0% +k asymptotically far away from the + + + align:start position:0% +k asymptotically far away from the +potential + + align:start position:0% + + + + align:start position:0% + +the wave function i can write as 1 over + + align:start position:0% +the wave function i can write as 1 over + + + align:start position:0% +the wave function i can write as 1 over +root 2 pi + + align:start position:0% + + + + align:start position:0% + +times e to the ikx + + align:start position:0% +times e to the ikx + + + align:start position:0% +times e to the ikx +when we're on the left hand side + + align:start position:0% +when we're on the left hand side + + + align:start position:0% +when we're on the left hand side +but left being on the left-hand side is + + align:start position:0% +but left being on the left-hand side is + + + align:start position:0% +but left being on the left-hand side is +equivalent to multiplying by a theta + + align:start position:0% +equivalent to multiplying by a theta + + + align:start position:0% +equivalent to multiplying by a theta +function of minus x minus x this is the + + align:start position:0% +function of minus x minus x this is the + + + align:start position:0% +function of minus x minus x this is the +function which is zero when its argument + + align:start position:0% +function which is zero when its argument + + + align:start position:0% +function which is zero when its argument +is negative and positive when its um + + align:start position:0% +is negative and positive when its um + + + align:start position:0% +is negative and positive when its um +argument is + + align:start position:0% +argument is + + + align:start position:0% +argument is +and one when its argument is positive + + align:start position:0% + + + + align:start position:0% + +plus + + align:start position:0% +plus + + + align:start position:0% +plus +we have the reflected term + + align:start position:0% +we have the reflected term + + + align:start position:0% +we have the reflected term +which has an amplitude r which is again + + align:start position:0% +which has an amplitude r which is again + + + align:start position:0% +which has an amplitude r which is again +a function of k this is the reflection + + align:start position:0% +a function of k this is the reflection + + + align:start position:0% +a function of k this is the reflection +amplitude also known as c upon a + + align:start position:0% +amplitude also known as c upon a + + + align:start position:0% +amplitude also known as c upon a +e to the minus psi kx + + align:start position:0% +e to the minus psi kx + + + align:start position:0% +e to the minus psi kx +again on the left hand side theta of + + align:start position:0% +again on the left hand side theta of + + + align:start position:0% +again on the left hand side theta of +minus x + + align:start position:0% + + + + align:start position:0% + +plus + + align:start position:0% +plus + + + align:start position:0% +plus +a transmission amplitude whose norm + + align:start position:0% +a transmission amplitude whose norm + + + align:start position:0% +a transmission amplitude whose norm +squared is transmission probability e to + + align:start position:0% +squared is transmission probability e to + + + align:start position:0% +squared is transmission probability e to +the ikx when we're on the right + + align:start position:0% +the ikx when we're on the right + + + align:start position:0% +the ikx when we're on the right +uh x whoops + + align:start position:0% +uh x whoops + + + align:start position:0% +uh x whoops +theta of x + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so this is just a slightly different + + align:start position:0% +so this is just a slightly different + + + align:start position:0% +so this is just a slightly different +notation + + align:start position:0% +notation + + + align:start position:0% +notation +than what we usually write + + align:start position:0% +than what we usually write + + + align:start position:0% +than what we usually write +with left and right separated + + align:start position:0% + + + + align:start position:0% + +so what we want to do now is we want to + + align:start position:0% +so what we want to do now is we want to + + + align:start position:0% +so what we want to do now is we want to +decompose our wavefunction in terms of + + align:start position:0% +decompose our wavefunction in terms of + + + align:start position:0% +decompose our wavefunction in terms of +the actual energy eigenstates + + align:start position:0% + + + + align:start position:0% + +and so + + align:start position:0% +and so + + + align:start position:0% +and so +the way we're going to do that + + align:start position:0% +the way we're going to do that + + + align:start position:0% +the way we're going to do that +and having done that having expanded our + + align:start position:0% +and having done that having expanded our + + + align:start position:0% +and having done that having expanded our +wave function in this eigens in this + + align:start position:0% +wave function in this eigens in this + + + align:start position:0% +wave function in this eigens in this +basis + + align:start position:0% +basis + + + align:start position:0% +basis +um we can determine the time evolution + + align:start position:0% +um we can determine the time evolution + + + align:start position:0% +um we can determine the time evolution +in the following way first we compute we + + align:start position:0% +in the following way first we compute we + + + align:start position:0% +in the following way first we compute we +expand the wave function at time 0 as an + + align:start position:0% +expand the wave function at time 0 as an + + + align:start position:0% +expand the wave function at time 0 as an +integral dk + + align:start position:0% + + + + align:start position:0% + +and i'm going to pull the root 2 pi out + + align:start position:0% + + + + align:start position:0% + +and we have some for a transform which + + align:start position:0% +and we have some for a transform which + + + align:start position:0% +and we have some for a transform which +i'm not going to call f tilde because + + align:start position:0% +i'm not going to call f tilde because + + + align:start position:0% +i'm not going to call f tilde because +it's slightly different than the f we + + align:start position:0% +it's slightly different than the f we + + + align:start position:0% +it's slightly different than the f we +used before but it's what it's what the + + align:start position:0% +used before but it's what it's what the + + + align:start position:0% +used before but it's what it's what the +expansion coefficients have to be f + + align:start position:0% +expansion coefficients have to be f + + + align:start position:0% +expansion coefficients have to be f +tilde of um + + align:start position:0% + + + + align:start position:0% + +yeah sorry f tilde of k times this beast + + align:start position:0% +yeah sorry f tilde of k times this beast + + + align:start position:0% +yeah sorry f tilde of k times this beast +phi sub k + + align:start position:0% +phi sub k + + + align:start position:0% +phi sub k +5k + + align:start position:0% + + + + align:start position:0% + +good and let me actually write this out + + align:start position:0% +good and let me actually write this out + + + align:start position:0% +good and let me actually write this out +in terms of the let me actually take + + align:start position:0% +in terms of the let me actually take + + + align:start position:0% +in terms of the let me actually take +this product and write it out in terms + + align:start position:0% +this product and write it out in terms + + + align:start position:0% +this product and write it out in terms +of the three terms so those three terms + + align:start position:0% +of the three terms so those three terms + + + align:start position:0% +of the three terms so those three terms +are going to be + + align:start position:0% +are going to be + + + align:start position:0% +are going to be +f of k + + align:start position:0% +f of k + + + align:start position:0% +f of k +again tilde e to the i kx + + align:start position:0% +again tilde e to the i kx + + + align:start position:0% +again tilde e to the i kx +theta minus x + + align:start position:0% +theta minus x + + + align:start position:0% +theta minus x +plus f tilde + + align:start position:0% +plus f tilde + + + align:start position:0% +plus f tilde +r + + align:start position:0% +r + + + align:start position:0% +r +e to the minus ikx + + align:start position:0% +e to the minus ikx + + + align:start position:0% +e to the minus ikx +theta minus x + + align:start position:0% +theta minus x + + + align:start position:0% +theta minus x +plus f tilde + + align:start position:0% + + + + align:start position:0% + +uh t + + align:start position:0% +uh t + + + align:start position:0% +uh t +e to the i k x + + align:start position:0% +e to the i k x + + + align:start position:0% +e to the i k x +theta of x + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so + + align:start position:0% +so + + + align:start position:0% +so +let's look at these terms this is this + + align:start position:0% +let's look at these terms this is this + + + align:start position:0% +let's look at these terms this is this +wave function now oh and sorry + + align:start position:0% +wave function now oh and sorry + + + align:start position:0% +wave function now oh and sorry +finally we want to look at the time + + align:start position:0% +finally we want to look at the time + + + align:start position:0% +finally we want to look at the time +evolution but this we started out as a + + align:start position:0% +evolution but this we started out as a + + + align:start position:0% +evolution but this we started out as a +superposition of states with definite + + align:start position:0% +superposition of states with definite + + + align:start position:0% +superposition of states with definite +energy labeled by k so we know the time + + align:start position:0% +energy labeled by k so we know the time + + + align:start position:0% +energy labeled by k so we know the time +evolution is e to the i k x minus omega + + align:start position:0% +evolution is e to the i k x minus omega + + + align:start position:0% +evolution is e to the i k x minus omega +t + + align:start position:0% +t + + + align:start position:0% +t +e to the i minus i k x plus omega t + + align:start position:0% +e to the i minus i k x plus omega t + + + align:start position:0% +e to the i minus i k x plus omega t +that's minus i omega t and k x minus + + align:start position:0% +that's minus i omega t and k x minus + + + align:start position:0% +that's minus i omega t and k x minus +omega t + + align:start position:0% +omega t + + + align:start position:0% +omega t +so we can immediately from + + align:start position:0% +so we can immediately from + + + align:start position:0% +so we can immediately from +from this time evolving wave function + + align:start position:0% +from this time evolving wave function + + + align:start position:0% +from this time evolving wave function +identify these two terms as terms with + + align:start position:0% +identify these two terms as terms with + + + align:start position:0% +identify these two terms as terms with +with + + align:start position:0% +with + + + align:start position:0% +with +a central peak moving to the right and + + align:start position:0% +a central peak moving to the right and + + + align:start position:0% +a central peak moving to the right and +this a central peak moving to the left + + align:start position:0% +this a central peak moving to the left + + + align:start position:0% +this a central peak moving to the left +kx plus omega t + + align:start position:0% + + + + align:start position:0% + +everyone cool with that + + align:start position:0% + + + + align:start position:0% + +questions + + align:start position:0% + + + + align:start position:0% + +or just where this came from + + align:start position:0% +or just where this came from + + + align:start position:0% +or just where this came from +oh good good good okay so this is just a + + align:start position:0% +oh good good good okay so this is just a + + + align:start position:0% +oh good good good okay so this is just a +notational thing so usually when i say a + + align:start position:0% +notational thing so usually when i say a + + + align:start position:0% +notational thing so usually when i say a +uh phi sub k is equal to + + align:start position:0% +uh phi sub k is equal to + + + align:start position:0% +uh phi sub k is equal to +on the left + + align:start position:0% +on the left + + + align:start position:0% +on the left +e to the ikx uh with some overall + + align:start position:0% +e to the ikx uh with some overall + + + align:start position:0% +e to the ikx uh with some overall +amplitude a + + align:start position:0% +amplitude a + + + align:start position:0% +amplitude a +let's say 1 over root 2 pi + + align:start position:0% +let's say 1 over root 2 pi + + + align:start position:0% +let's say 1 over root 2 pi +e to the ikx + + align:start position:0% +e to the ikx + + + align:start position:0% +e to the ikx +plus + + align:start position:0% +plus + + + align:start position:0% +plus +c over a + + align:start position:0% +c over a + + + align:start position:0% +c over a +e to the minus ikx + + align:start position:0% +e to the minus ikx + + + align:start position:0% +e to the minus ikx +right on the left and i'm just going to + + align:start position:0% +right on the left and i'm just going to + + + align:start position:0% +right on the left and i'm just going to +call this because this is the reflected + + align:start position:0% +call this because this is the reflected + + + align:start position:0% +call this because this is the reflected +wave i'm just going to call this r + + align:start position:0% +wave i'm just going to call this r + + + align:start position:0% +wave i'm just going to call this r +okay and then on the right + + align:start position:0% +okay and then on the right + + + align:start position:0% +okay and then on the right +we have e to the ikx + + align:start position:0% +we have e to the ikx + + + align:start position:0% +we have e to the ikx +there's only a wave traveling to the + + align:start position:0% +there's only a wave traveling to the + + + align:start position:0% +there's only a wave traveling to the +right and the coefficient is the + + align:start position:0% +right and the coefficient is the + + + align:start position:0% +right and the coefficient is the +transmission amplitude so this is what + + align:start position:0% +transmission amplitude so this is what + + + align:start position:0% +transmission amplitude so this is what +we normally write but then i'm using the + + align:start position:0% +we normally write but then i'm using the + + + align:start position:0% +we normally write but then i'm using the +function the theta function so called + + align:start position:0% +function the theta function so called + + + align:start position:0% +function the theta function so called +theta function theta of x is defined as + + align:start position:0% +theta function theta of x is defined as + + + align:start position:0% +theta function theta of x is defined as +zero when x is less than zero and one + + align:start position:0% +zero when x is less than zero and one + + + align:start position:0% +zero when x is less than zero and one +when x is greater than zero + + align:start position:0% +when x is greater than zero + + + align:start position:0% +when x is greater than zero +okay so this is a function one so this + + align:start position:0% +okay so this is a function one so this + + + align:start position:0% +okay so this is a function one so this +allows me using theta function allows me + + align:start position:0% +allows me using theta function allows me + + + align:start position:0% +allows me using theta function allows me +to write this thing as a single function + + align:start position:0% +to write this thing as a single function + + + align:start position:0% +to write this thing as a single function +without having to goose around with lots + + align:start position:0% +without having to goose around with lots + + + align:start position:0% +without having to goose around with lots +of terms is that cool + + align:start position:0% +of terms is that cool + + + align:start position:0% +of terms is that cool +great + + align:start position:0% +great + + + align:start position:0% +great +i will just take into account + + align:start position:0% + + + + align:start position:0% + +because otherwise we should have + + align:start position:0% +because otherwise we should have + + + align:start position:0% +because otherwise we should have +something + + align:start position:0% +something + + + align:start position:0% +something +excellent excellent thank you so much so + + align:start position:0% +excellent excellent thank you so much so + + + align:start position:0% +excellent excellent thank you so much so +here what i want to do is + + align:start position:0% +here what i want to do is + + + align:start position:0% +here what i want to do is +thank you what i want to do is i want to + + align:start position:0% +thank you what i want to do is i want to + + + align:start position:0% +thank you what i want to do is i want to +think of the wave function + + align:start position:0% +think of the wave function + + + align:start position:0% +think of the wave function +so this is a good description when the + + align:start position:0% +so this is a good description when the + + + align:start position:0% +so this is a good description when the +particle is far far away + + align:start position:0% +particle is far far away + + + align:start position:0% +particle is far far away +and this is a good description when the + + align:start position:0% +and this is a good description when the + + + align:start position:0% +and this is a good description when the +particle is not in the potential so i + + align:start position:0% +particle is not in the potential so i + + + align:start position:0% +particle is not in the potential so i +want to just imagine this sorry thank + + align:start position:0% +want to just imagine this sorry thank + + + align:start position:0% +want to just imagine this sorry thank +you i totally glossed over this step i + + align:start position:0% +you i totally glossed over this step i + + + align:start position:0% +you i totally glossed over this step i +want to imagine this as a potential + + align:start position:0% +want to imagine this as a potential + + + align:start position:0% +want to imagine this as a potential +where all of the matching is implemented + + align:start position:0% +where all of the matching is implemented + + + align:start position:0% +where all of the matching is implemented +at x equals zero + + align:start position:0% +at x equals zero + + + align:start position:0% +at x equals zero +okay + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% +um + + + align:start position:0% +um +so when i write it in this fashion + + align:start position:0% +so when i write it in this fashion + + + align:start position:0% +so when i write it in this fashion +but the better way to another equivalent + + align:start position:0% +but the better way to another equivalent + + + align:start position:0% +but the better way to another equivalent +way to think about this is this is a + + align:start position:0% +way to think about this is this is a + + + align:start position:0% +way to think about this is this is a +good description of the wave function + + align:start position:0% +good description of the wave function + + + align:start position:0% +good description of the wave function +when we're not inside the well + + align:start position:0% +when we're not inside the well + + + align:start position:0% +when we're not inside the well +so for the purposes of the rest of the + + align:start position:0% +so for the purposes of the rest of the + + + align:start position:0% +so for the purposes of the rest of the +analysis that i'm going to do this is + + align:start position:0% +analysis that i'm going to do this is + + + align:start position:0% +analysis that i'm going to do this is +exactly what the form of the wave + + align:start position:0% +exactly what the form of the wave + + + align:start position:0% +exactly what the form of the wave +function is when we're not inside the + + align:start position:0% +function is when we're not inside the + + + align:start position:0% +function is when we're not inside the +well + + align:start position:0% +well + + + align:start position:0% +well +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and then let's just not use this to ask + + align:start position:0% +and then let's just not use this to ask + + + align:start position:0% +and then let's just not use this to ask +about questions inside the well + + align:start position:0% +about questions inside the well + + + align:start position:0% +about questions inside the well +when i write it in this theta form or + + align:start position:0% +when i write it in this theta form or + + + align:start position:0% +when i write it in this theta form or +for that matter when i write it in this + + align:start position:0% +for that matter when i write it in this + + + align:start position:0% +for that matter when i write it in this +form this is not the the form what i + + align:start position:0% +form this is not the the form what i + + + align:start position:0% +form this is not the the form what i +mean is left of the well + + align:start position:0% +mean is left of the well + + + align:start position:0% +mean is left of the well +and right of the well + + align:start position:0% +and right of the well + + + align:start position:0% +and right of the well +and inside + + align:start position:0% + + + + align:start position:0% + +t e to the ikx + + align:start position:0% +t e to the ikx + + + align:start position:0% +t e to the ikx +inside it's doing something else + + align:start position:0% +inside it's doing something else + + + align:start position:0% +inside it's doing something else +but we don't want to ask questions about + + align:start position:0% +but we don't want to ask questions about + + + align:start position:0% +but we don't want to ask questions about +it okay + + align:start position:0% +it okay + + + align:start position:0% +it okay +cool that's just going to simplify my + + align:start position:0% +cool that's just going to simplify my + + + align:start position:0% +cool that's just going to simplify my +life + + align:start position:0% + + + + align:start position:0% + +root of capital yeah + + align:start position:0% +root of capital yeah + + + align:start position:0% +root of capital yeah +it's the square root of capital t but + + align:start position:0% +it's the square root of capital t but + + + align:start position:0% +it's the square root of capital t but +you've got to be careful because there + + align:start position:0% +you've got to be careful because there + + + align:start position:0% +you've got to be careful because there +can be a phase + + align:start position:0% +can be a phase + + + align:start position:0% +can be a phase +remember this is the amplitude and what + + align:start position:0% +remember this is the amplitude and what + + + align:start position:0% +remember this is the amplitude and what +it really is is this reflection is b + + align:start position:0% +it really is is this reflection is b + + + align:start position:0% +it really is is this reflection is b +over a + + align:start position:0% +over a + + + align:start position:0% +over a +and these guys are complex numbers and + + align:start position:0% +and these guys are complex numbers and + + + align:start position:0% +and these guys are complex numbers and +it's true that b over a norm squared is + + align:start position:0% +it's true that b over a norm squared is + + + align:start position:0% +it's true that b over a norm squared is +the transmission probability + + align:start position:0% +the transmission probability + + + align:start position:0% +the transmission probability +but b over a has a phase and that + + align:start position:0% +but b over a has a phase and that + + + align:start position:0% +but b over a has a phase and that +quantity i'm going to call t and we'll + + align:start position:0% +quantity i'm going to call t and we'll + + + align:start position:0% +quantity i'm going to call t and we'll +interpret that in more detail in a few + + align:start position:0% +interpret that in more detail in a few + + + align:start position:0% +interpret that in more detail in a few +minutes + + align:start position:0% +minutes + + + align:start position:0% +minutes +okay + + align:start position:0% +okay + + + align:start position:0% +okay +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so it's of this form + + align:start position:0% +so it's of this form + + + align:start position:0% +so it's of this form +and i just want to look at each of these + + align:start position:0% +and i just want to look at each of these + + + align:start position:0% +and i just want to look at each of these +three terms + + align:start position:0% +three terms + + + align:start position:0% +three terms +and in particular i want to focus on + + align:start position:0% +and in particular i want to focus on + + + align:start position:0% +and in particular i want to focus on +them at time 0. + + align:start position:0% +them at time 0. + + + align:start position:0% +them at time 0. +so at t equals 0 what does this look + + align:start position:0% +so at t equals 0 what does this look + + + align:start position:0% +so at t equals 0 what does this look +like well that first term is integral dk + + align:start position:0% +like well that first term is integral dk + + + align:start position:0% +like well that first term is integral dk +of f of k + + align:start position:0% +of f of k + + + align:start position:0% +of f of k +e to the ikx + + align:start position:0% +e to the ikx + + + align:start position:0% +e to the ikx +minus omega t + + align:start position:0% +minus omega t + + + align:start position:0% +minus omega t +okay theta minus x + + align:start position:0% +okay theta minus x + + + align:start position:0% +okay theta minus x +notice that theta minus x is independent + + align:start position:0% +notice that theta minus x is independent + + + align:start position:0% +notice that theta minus x is independent +of + + align:start position:0% +of + + + align:start position:0% +of +k it's independent of the integral so + + align:start position:0% +k it's independent of the integral so + + + align:start position:0% +k it's independent of the integral so +this is just a function times theta of + + align:start position:0% +this is just a function times theta of + + + align:start position:0% +this is just a function times theta of +minus x + + align:start position:0% +minus x + + + align:start position:0% +minus x +okay and this function was constructed + + align:start position:0% +okay and this function was constructed + + + align:start position:0% +okay and this function was constructed +to give us the initial gaussian + + align:start position:0% + + + + align:start position:0% + +so this is just oh sorry and this was at + + align:start position:0% +so this is just oh sorry and this was at + + + align:start position:0% +so this is just oh sorry and this was at +t equals 0. so this is just our gaussian + + align:start position:0% +t equals 0. so this is just our gaussian + + + align:start position:0% +t equals 0. so this is just our gaussian +at position x naught + + align:start position:0% +at position x naught + + + align:start position:0% +at position x naught +centered around value k naught + + align:start position:0% +centered around value k naught + + + align:start position:0% +centered around value k naught +at time equals zero + + align:start position:0% +at time equals zero + + + align:start position:0% +at time equals zero +theta of minus x + + align:start position:0% + + + + align:start position:0% + +okay this is just saying that um sorry + + align:start position:0% +okay this is just saying that um sorry + + + align:start position:0% +okay this is just saying that um sorry +at x at position x sorry of x naught + + align:start position:0% +at x at position x sorry of x naught + + + align:start position:0% +at x at position x sorry of x naught +so this all this function is is the this + + align:start position:0% +so this all this function is is the this + + + align:start position:0% +so this all this function is is the this +is the fourier transform of our gaussian + + align:start position:0% +is the fourier transform of our gaussian + + + align:start position:0% +is the fourier transform of our gaussian +and we're undoing the fourier transform + + align:start position:0% +and we're undoing the fourier transform + + + align:start position:0% +and we're undoing the fourier transform +so this is just giving us our gaussian + + align:start position:0% +so this is just giving us our gaussian + + + align:start position:0% +so this is just giving us our gaussian +back + + align:start position:0% +back + + + align:start position:0% +back +and as long as the particle is far away + + align:start position:0% +and as long as the particle is far away + + + align:start position:0% +and as long as the particle is far away +from the well so here's the well and + + align:start position:0% +from the well so here's the well and + + + align:start position:0% +from the well so here's the well and +here's our wave packet uh that theta + + align:start position:0% +here's our wave packet uh that theta + + + align:start position:0% +here's our wave packet uh that theta +function is totally irrelevant because + + align:start position:0% +function is totally irrelevant because + + + align:start position:0% +function is totally irrelevant because +the gaussian makes it zero away from the + + align:start position:0% +the gaussian makes it zero away from the + + + align:start position:0% +the gaussian makes it zero away from the +center of the gaussian anyway + + align:start position:0% + + + + align:start position:0% + +and so just as a quick question if we + + align:start position:0% +and so just as a quick question if we + + + align:start position:0% +and so just as a quick question if we +look at this as a function of t so we + + align:start position:0% +look at this as a function of t so we + + + align:start position:0% +look at this as a function of t so we +put back in the minus omega t + + align:start position:0% + + + + align:start position:0% + +so if we put back in the time dependence + + align:start position:0% + + + + align:start position:0% + +this is a wave + + align:start position:0% +this is a wave + + + align:start position:0% +this is a wave +that's moving to the right and we need + + align:start position:0% +that's moving to the right and we need + + + align:start position:0% +that's moving to the right and we need +to make to be more precise about that + + align:start position:0% +to make to be more precise about that + + + align:start position:0% +to make to be more precise about that +what does it mean to say it's a wave + + align:start position:0% +what does it mean to say it's a wave + + + align:start position:0% +what does it mean to say it's a wave +moving to the right + + align:start position:0% +moving to the right + + + align:start position:0% +moving to the right +well this is an envelope + + align:start position:0% +well this is an envelope + + + align:start position:0% +well this is an envelope +on this + + align:start position:0% +on this + + + align:start position:0% +on this +set of plane waves and the envelope by + + align:start position:0% +set of plane waves and the envelope by + + + align:start position:0% +set of plane waves and the envelope by +construction + + align:start position:0% +construction + + + align:start position:0% +construction +was well localized around position x but + + align:start position:0% +was well localized around position x but + + + align:start position:0% +was well localized around position x but +it was also well localized in momentum + + align:start position:0% +it was also well localized in momentum + + + align:start position:0% +it was also well localized in momentum +and in particular the fourier transform + + align:start position:0% +and in particular the fourier transform + + + align:start position:0% +and in particular the fourier transform +is well localized around the momentum + + align:start position:0% +is well localized around the momentum + + + align:start position:0% +is well localized around the momentum +k naught + + align:start position:0% + + + + align:start position:0% + +and so using using the method of + + align:start position:0% +and so using using the method of + + + align:start position:0% +and so using using the method of +stationary phase or just asking where is + + align:start position:0% +stationary phase or just asking where is + + + align:start position:0% +stationary phase or just asking where is +the + + align:start position:0% +the + + + align:start position:0% +the +where is the phase constant stationary + + align:start position:0% +where is the phase constant stationary + + + align:start position:0% +where is the phase constant stationary +we get that the center of the the + + align:start position:0% +we get that the center of the the + + + align:start position:0% +we get that the center of the the +peaks the the central peak of the wave + + align:start position:0% +peaks the the central peak of the wave + + + align:start position:0% +peaks the the central peak of the wave +function + + align:start position:0% +function + + + align:start position:0% +function +satisfies the equation ddk naught + + align:start position:0% +satisfies the equation ddk naught + + + align:start position:0% +satisfies the equation ddk naught +if you're not familiar with stationary + + align:start position:0% +if you're not familiar with stationary + + + align:start position:0% +if you're not familiar with stationary +phase let the + + align:start position:0% +phase let the + + + align:start position:0% +phase let the +restoration instructors uh know and they + + align:start position:0% +restoration instructors uh know and they + + + align:start position:0% +restoration instructors uh know and they +will discuss it for you um + + align:start position:0% +will discuss it for you um + + + align:start position:0% +will discuss it for you um +so this the the + + align:start position:0% +so this the the + + + align:start position:0% +so this the the +points of stationary phase of this uh + + align:start position:0% +points of stationary phase of this uh + + + align:start position:0% +points of stationary phase of this uh +this superposition of this wave packet + + align:start position:0% +this superposition of this wave packet + + + align:start position:0% +this superposition of this wave packet +lie at the position ddk naught of kx + + align:start position:0% +lie at the position ddk naught of kx + + + align:start position:0% +lie at the position ddk naught of kx +sorry ddk of kx minus omega of kt + + align:start position:0% + + + + align:start position:0% + +evaluated at the peak k naught + + align:start position:0% +evaluated at the peak k naught + + + align:start position:0% +evaluated at the peak k naught +of the distribution + + align:start position:0% +of the distribution + + + align:start position:0% +of the distribution +but ddk of kx minus omega t is for the + + align:start position:0% +but ddk of kx minus omega t is for the + + + align:start position:0% +but ddk of kx minus omega t is for the +first term x and for the second term ddk + + align:start position:0% +first term x and for the second term ddk + + + align:start position:0% +first term x and for the second term ddk +of omega well we know that omega we're + + align:start position:0% +of omega well we know that omega we're + + + align:start position:0% +of omega well we know that omega we're +in the free particle regime + + align:start position:0% +in the free particle regime + + + align:start position:0% +in the free particle regime +um omega where did it go um well we all + + align:start position:0% +um omega where did it go um well we all + + + align:start position:0% +um omega where did it go um well we all +know what it is it's h bar h bar k + + align:start position:0% +know what it is it's h bar h bar k + + + align:start position:0% +know what it is it's h bar h bar k +squared upon 2 m we take a derivative + + align:start position:0% +squared upon 2 m we take a derivative + + + align:start position:0% +squared upon 2 m we take a derivative +with respect to k we get h bar k over m + + align:start position:0% +with respect to k we get h bar k over m + + + align:start position:0% +with respect to k we get h bar k over m +the twos cancel so x minus + + align:start position:0% +the twos cancel so x minus + + + align:start position:0% +the twos cancel so x minus +h bar k + + align:start position:0% +h bar k + + + align:start position:0% +h bar k +over m + + align:start position:0% +over m + + + align:start position:0% +over m +t + + align:start position:0% +t + + + align:start position:0% +t +and a place where this point where this + + align:start position:0% +and a place where this point where this + + + align:start position:0% +and a place where this point where this +phase is zero + + align:start position:0% +phase is zero + + + align:start position:0% +phase is zero +where the phase is stationary + + align:start position:0% +where the phase is stationary + + + align:start position:0% +where the phase is stationary +moves over time as x is equal to h bar k + + align:start position:0% +moves over time as x is equal to h bar k + + + align:start position:0% +moves over time as x is equal to h bar k +over m + + align:start position:0% +over m + + + align:start position:0% +over m +t + + align:start position:0% +t + + + align:start position:0% +t +but h bar k over m that's the class + + align:start position:0% +but h bar k over m that's the class + + + align:start position:0% +but h bar k over m that's the class +that's the momentum + + align:start position:0% +that's the momentum + + + align:start position:0% +that's the momentum +p over m that's the classical velocity + + align:start position:0% +p over m that's the classical velocity + + + align:start position:0% +p over m that's the classical velocity +so this is v naught t + + align:start position:0% +so this is v naught t + + + align:start position:0% +so this is v naught t +the velocity associated with that + + align:start position:0% +the velocity associated with that + + + align:start position:0% +the velocity associated with that +momentum + + align:start position:0% +momentum + + + align:start position:0% +momentum +so this is good we've done the right job + + align:start position:0% +so this is good we've done the right job + + + align:start position:0% +so this is good we've done the right job +of setting up our wave packet we built a + + align:start position:0% +of setting up our wave packet we built a + + + align:start position:0% +of setting up our wave packet we built a +gaussian that was far away that was + + align:start position:0% +gaussian that was far away that was + + + align:start position:0% +gaussian that was far away that was +moving in with a fixed velocity towards + + align:start position:0% +moving in with a fixed velocity towards + + + align:start position:0% +moving in with a fixed velocity towards +the barrier and now we want to know what + + align:start position:0% +the barrier and now we want to know what + + + align:start position:0% +the barrier and now we want to know what +happens after it collides off the + + align:start position:0% +happens after it collides off the + + + align:start position:0% +happens after it collides off the +barrier + + align:start position:0% +barrier + + + align:start position:0% +barrier +cool + + align:start position:0% +cool + + + align:start position:0% +cool +so what we really want to ask is that + + align:start position:0% +so what we really want to ask is that + + + align:start position:0% +so what we really want to ask is that +late times what does the wave function + + align:start position:0% +late times what does the wave function + + + align:start position:0% +late times what does the wave function +look like well at late times the + + align:start position:0% +look like well at late times the + + + align:start position:0% +look like well at late times the +position of this so again we're focusing + + align:start position:0% +position of this so again we're focusing + + + align:start position:0% +position of this so again we're focusing +on the first term the position of this + + align:start position:0% +on the first term the position of this + + + align:start position:0% +on the first term the position of this +wave packet at late times at positive t + + align:start position:0% +wave packet at late times at positive t + + + align:start position:0% +wave packet at late times at positive t +is positive + + align:start position:0% +is positive + + + align:start position:0% +is positive +and when it's positive then this theta + + align:start position:0% +and when it's positive then this theta + + + align:start position:0% +and when it's positive then this theta +function kills its contribution to the + + align:start position:0% +function kills its contribution to the + + + align:start position:0% +function kills its contribution to the +overall wave function + + align:start position:0% +overall wave function + + + align:start position:0% +overall wave function +right + + align:start position:0% +right + + + align:start position:0% +right +this theta is now theta of minus a + + align:start position:0% +this theta is now theta of minus a + + + align:start position:0% +this theta is now theta of minus a +positive number and this gaussian is + + align:start position:0% +positive number and this gaussian is + + + align:start position:0% +positive number and this gaussian is +gone + + align:start position:0% + + + + align:start position:0% + +what is it replaced by well these two + + align:start position:0% +what is it replaced by well these two + + + align:start position:0% +what is it replaced by well these two +terms aren't necessarily zero in + + align:start position:0% +terms aren't necessarily zero in + + + align:start position:0% +terms aren't necessarily zero in +particular this one is moving to the + + align:start position:0% +particular this one is moving to the + + + align:start position:0% +particular this one is moving to the +left so x is as time goes forward x is + + align:start position:0% +left so x is as time goes forward x is + + + align:start position:0% +left so x is as time goes forward x is +moving further and further to the left + + align:start position:0% +moving further and further to the left + + + align:start position:0% +moving further and further to the left +and so this theta function starts + + align:start position:0% +and so this theta function starts + + + align:start position:0% +and so this theta function starts +turning on + + align:start position:0% +turning on + + + align:start position:0% +turning on +and similarly as x goes positive this + + align:start position:0% +and similarly as x goes positive this + + + align:start position:0% +and similarly as x goes positive this +theta function starts turning on as well + + align:start position:0% +theta function starts turning on as well + + + align:start position:0% +theta function starts turning on as well +let's focus on this third term + + align:start position:0% + + + + align:start position:0% + +transmitted term + + align:start position:0% +transmitted term + + + align:start position:0% +transmitted term +so let's focus on this third term + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +in particular that term looks like + + align:start position:0% +in particular that term looks like + + + align:start position:0% +in particular that term looks like +integral dk over root 2 pi + + align:start position:0% + + + + align:start position:0% + +f + + align:start position:0% +f + + + align:start position:0% +f +times the transmission amplitude times e + + align:start position:0% +times the transmission amplitude times e + + + align:start position:0% +times the transmission amplitude times e +to the i kx + + align:start position:0% +to the i kx + + + align:start position:0% +to the i kx +minus uh omega t + + align:start position:0% + + + + align:start position:0% + +okay and there's an overall theta of x + + align:start position:0% +okay and there's an overall theta of x + + + align:start position:0% +okay and there's an overall theta of x +outside but for late times where the + + align:start position:0% +outside but for late times where the + + + align:start position:0% +outside but for late times where the +center of the wave packet for the + + align:start position:0% +center of the wave packet for the + + + align:start position:0% +center of the wave packet for the +transmitted wave packet should be + + align:start position:0% +transmitted wave packet should be + + + align:start position:0% +transmitted wave packet should be +positive the state is just going to be + + align:start position:0% +positive the state is just going to be + + + align:start position:0% +positive the state is just going to be +one so we can safely ignore it + + align:start position:0% +one so we can safely ignore it + + + align:start position:0% +one so we can safely ignore it +it's just saying we're far off to the + + align:start position:0% +it's just saying we're far off to the + + + align:start position:0% +it's just saying we're far off to the +right + + align:start position:0% +right + + + align:start position:0% +right +and now i want to i want to do one last + + align:start position:0% +and now i want to i want to do one last + + + align:start position:0% +and now i want to i want to do one last +thing this was an overall + + align:start position:0% +thing this was an overall + + + align:start position:0% +thing this was an overall +this was an overall + + align:start position:0% +this was an overall + + + align:start position:0% +this was an overall +envelope + + align:start position:0% +envelope + + + align:start position:0% +envelope +this t was our scattering amplitude and + + align:start position:0% +this t was our scattering amplitude and + + + align:start position:0% +this t was our scattering amplitude and +i want to write it in the following form + + align:start position:0% +i want to write it in the following form + + + align:start position:0% +i want to write it in the following form +i want to write it as root t + + align:start position:0% +i want to write it as root t + + + align:start position:0% +i want to write it as root t +e to the minus i phi + + align:start position:0% +e to the minus i phi + + + align:start position:0% +e to the minus i phi +where phi is okay so what this is saying + + align:start position:0% +where phi is okay so what this is saying + + + align:start position:0% +where phi is okay so what this is saying +is that indeed as was pointed out + + align:start position:0% +is that indeed as was pointed out + + + align:start position:0% +is that indeed as was pointed out +earlier the norm squared of this + + align:start position:0% +earlier the norm squared of this + + + align:start position:0% +earlier the norm squared of this +coefficient t is the transmission + + align:start position:0% +coefficient t is the transmission + + + align:start position:0% +coefficient t is the transmission +probability + + align:start position:0% +probability + + + align:start position:0% +probability +but it has a phase and what i want to + + align:start position:0% +but it has a phase and what i want to + + + align:start position:0% +but it has a phase and what i want to +know is what does this phase mean + + align:start position:0% +know is what does this phase mean + + + align:start position:0% +know is what does this phase mean +what information is contained in this + + align:start position:0% +what information is contained in this + + + align:start position:0% +what information is contained in this +phase and that's what we're about to + + align:start position:0% +phase and that's what we're about to + + + align:start position:0% +phase and that's what we're about to +find + + align:start position:0% +find + + + align:start position:0% +find +so let's put that in here we have root t + + align:start position:0% + + + + align:start position:0% + +and minus phi + + align:start position:0% +and minus phi + + + align:start position:0% +and minus phi +okay where omega and k and phi are both + + align:start position:0% +okay where omega and k and phi are both + + + align:start position:0% +okay where omega and k and phi are both +functions of k + + align:start position:0% +functions of k + + + align:start position:0% +functions of k +because the transmission amplitudes + + align:start position:0% +because the transmission amplitudes + + + align:start position:0% +because the transmission amplitudes +depend on + + align:start position:0% +depend on + + + align:start position:0% +depend on +the momentum or the energy + + align:start position:0% +the momentum or the energy + + + align:start position:0% +the momentum or the energy +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and now i again want to know + + align:start position:0% +and now i again want to know + + + align:start position:0% +and now i again want to know +how does this wave packet move if i look + + align:start position:0% +how does this wave packet move if i look + + + align:start position:0% +how does this wave packet move if i look +at this wave packet how does it move on + + align:start position:0% +at this wave packet how does it move on + + + align:start position:0% +at this wave packet how does it move on +mass how does it has a group of waves + + align:start position:0% +mass how does it has a group of waves + + + align:start position:0% +mass how does it has a group of waves +how does this wave packet move + + align:start position:0% +how does this wave packet move + + + align:start position:0% +how does this wave packet move +in particular with y velocity + + align:start position:0% +in particular with y velocity + + + align:start position:0% +in particular with y velocity +so i'll do again make an argument by + + align:start position:0% +so i'll do again make an argument by + + + align:start position:0% +so i'll do again make an argument by +stationary phase i'll look at a point of + + align:start position:0% +stationary phase i'll look at a point of + + + align:start position:0% +stationary phase i'll look at a point of +of phase equals 0 and ask how it moves + + align:start position:0% +of phase equals 0 and ask how it moves + + + align:start position:0% +of phase equals 0 and ask how it moves +over time and the point of stationary + + align:start position:0% +over time and the point of stationary + + + align:start position:0% +over time and the point of stationary +phase is again given by ddk of the phase + + align:start position:0% +phase is again given by ddk of the phase + + + align:start position:0% +phase is again given by ddk of the phase +kx + + align:start position:0% +kx + + + align:start position:0% +kx +minus omega of kt + + align:start position:0% +minus omega of kt + + + align:start position:0% +minus omega of kt +minus 5k + + align:start position:0% +minus 5k + + + align:start position:0% +minus 5k +is equal to zero evaluated at k0 which + + align:start position:0% +is equal to zero evaluated at k0 which + + + align:start position:0% +is equal to zero evaluated at k0 which +is where our envelope is sharply peaked + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +this expression is equal to this is + + align:start position:0% +this expression is equal to this is + + + align:start position:0% +this expression is equal to this is +again x + + align:start position:0% +again x + + + align:start position:0% +again x +minus d omega dk that's the classical + + align:start position:0% +minus d omega dk that's the classical + + + align:start position:0% +minus d omega dk that's the classical +velocity v naught t + + align:start position:0% +velocity v naught t + + + align:start position:0% +velocity v naught t +minus + + align:start position:0% +minus + + + align:start position:0% +minus +d phi + + align:start position:0% +d phi + + + align:start position:0% +d phi +d k + + align:start position:0% +d k + + + align:start position:0% +d k +but just as a note d phi + + align:start position:0% +but just as a note d phi + + + align:start position:0% +but just as a note d phi +d k + + align:start position:0% +d k + + + align:start position:0% +d k +is equal to d omega d k + + align:start position:0% +is equal to d omega d k + + + align:start position:0% +is equal to d omega d k +d phi + + align:start position:0% +d phi + + + align:start position:0% +d phi +d omega + + align:start position:0% +d omega + + + align:start position:0% +d omega +but this is equal to this is just the + + align:start position:0% +but this is equal to this is just the + + + align:start position:0% +but this is equal to this is just the +chain rule the omega dk that's the + + align:start position:0% +chain rule the omega dk that's the + + + align:start position:0% +chain rule the omega dk that's the +classical velocity d omega or defined + + align:start position:0% +classical velocity d omega or defined + + + align:start position:0% +classical velocity d omega or defined +the omega + + align:start position:0% +the omega + + + align:start position:0% +the omega +that's d phi + + align:start position:0% +that's d phi + + + align:start position:0% +that's d phi +d e + + align:start position:0% +d e + + + align:start position:0% +d e +times h bar i just multiplied by h bar + + align:start position:0% +times h bar i just multiplied by h bar + + + align:start position:0% +times h bar i just multiplied by h bar +on the top and bottom + + align:start position:0% +on the top and bottom + + + align:start position:0% +on the top and bottom +so this is equal to + + align:start position:0% +so this is equal to + + + align:start position:0% +so this is equal to +x minus v naught + + align:start position:0% +x minus v naught + + + align:start position:0% +x minus v naught +t + + align:start position:0% +t + + + align:start position:0% +t +plus + + align:start position:0% +plus + + + align:start position:0% +plus +h bar + + align:start position:0% +h bar + + + align:start position:0% +h bar +d phi d e + + align:start position:0% + + + + align:start position:0% + +so first off let's just make sure that + + align:start position:0% +so first off let's just make sure that + + + align:start position:0% +so first off let's just make sure that +the units make sense + + align:start position:0% +the units make sense + + + align:start position:0% +the units make sense +that's a length that's a velocity so + + align:start position:0% +that's a length that's a velocity so + + + align:start position:0% +that's a length that's a velocity so +they said better have units of time time + + align:start position:0% +they said better have units of time time + + + align:start position:0% +they said better have units of time time +that's good so h bar times d phase over + + align:start position:0% +that's good so h bar times d phase over + + + align:start position:0% +that's good so h bar times d phase over +d e well a phase is dimensionless energy + + align:start position:0% +d e well a phase is dimensionless energy + + + align:start position:0% +d e well a phase is dimensionless energy +is units of energy h is energy times + + align:start position:0% +is units of energy h is energy times + + + align:start position:0% +is units of energy h is energy times +time so this dimensionally works out so + + align:start position:0% +time so this dimensionally works out so + + + align:start position:0% +time so this dimensionally works out so +this is zero so the claim is that the + + align:start position:0% +this is zero so the claim is that the + + + align:start position:0% +this is zero so the claim is that the +point of stationary phase has this + + align:start position:0% +point of stationary phase has this + + + align:start position:0% +point of stationary phase has this +derivative equal to zero so setting this + + align:start position:0% +derivative equal to zero so setting this + + + align:start position:0% +derivative equal to zero so setting this +equal to zero tells us that the the peak + + align:start position:0% +equal to zero tells us that the the peak + + + align:start position:0% +equal to zero tells us that the the peak +of the wave function moves + + align:start position:0% +of the wave function moves + + + align:start position:0% +of the wave function moves +according to this equation + + align:start position:0% + + + + align:start position:0% + +and so now so this is really satisfying + + align:start position:0% +and so now so this is really satisfying + + + align:start position:0% +and so now so this is really satisfying +this should be really satisfying for a + + align:start position:0% +this should be really satisfying for a + + + align:start position:0% +this should be really satisfying for a +couple of reasons first off it tells you + + align:start position:0% +couple of reasons first off it tells you + + + align:start position:0% +couple of reasons first off it tells you +that the peak of the transmitted wave + + align:start position:0% +that the peak of the transmitted wave + + + align:start position:0% +that the peak of the transmitted wave +the peak of the transmitted wave packet + + align:start position:0% +the peak of the transmitted wave packet + + + align:start position:0% +the peak of the transmitted wave packet +not just a plane wave the peak of the + + align:start position:0% +not just a plane wave the peak of the + + + align:start position:0% +not just a plane wave the peak of the +actual wave packet well localized moves + + align:start position:0% +actual wave packet well localized moves + + + align:start position:0% +actual wave packet well localized moves +with overall velocity v naught the + + align:start position:0% +with overall velocity v naught the + + + align:start position:0% +with overall velocity v naught the +constant velocity that we started with + + align:start position:0% +constant velocity that we started with + + + align:start position:0% +constant velocity that we started with +and that's good if it was moving with + + align:start position:0% +and that's good if it was moving with + + + align:start position:0% +and that's good if it was moving with +some other velocity we would have lost + + align:start position:0% +some other velocity we would have lost + + + align:start position:0% +some other velocity we would have lost +energy somehow that would be + + align:start position:0% +energy somehow that would be + + + align:start position:0% +energy somehow that would be +not so sensible + + align:start position:0% +not so sensible + + + align:start position:0% +not so sensible +so this wave packet is moving with an + + align:start position:0% +so this wave packet is moving with an + + + align:start position:0% +so this wave packet is moving with an +overall velocity v naught however + + align:start position:0% +overall velocity v naught however + + + align:start position:0% +overall velocity v naught however +it doesn't + + align:start position:0% +it doesn't + + + align:start position:0% +it doesn't +move + + align:start position:0% +move + + + align:start position:0% +move +uh at the same it doesn't move along + + align:start position:0% +uh at the same it doesn't move along + + + align:start position:0% +uh at the same it doesn't move along +just as the original wave packet's peak + + align:start position:0% +just as the original wave packet's peak + + + align:start position:0% +just as the original wave packet's peak +had + + align:start position:0% +had + + + align:start position:0% +had +it moves as if shifted in time + + align:start position:0% +it moves as if shifted in time + + + align:start position:0% +it moves as if shifted in time +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so the phase and more to the point the + + align:start position:0% +so the phase and more to the point the + + + align:start position:0% +so the phase and more to the point the +gradient of the phase with respect to + + align:start position:0% +gradient of the phase with respect to + + + align:start position:0% +gradient of the phase with respect to +energy the rate of change with energy of + + align:start position:0% +energy the rate of change with energy of + + + align:start position:0% +energy the rate of change with energy of +the phase + + align:start position:0% +the phase + + + align:start position:0% +the phase +times h-bar + + align:start position:0% +times h-bar + + + align:start position:0% +times h-bar +is giving us a phase a shift in the time + + align:start position:0% + + + + align:start position:0% + +of where the wave packet is so what does + + align:start position:0% +of where the wave packet is so what does + + + align:start position:0% +of where the wave packet is so what does +that mean + + align:start position:0% + + + + align:start position:0% + +so let's be precise about this + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% + + + + align:start position:0% + +so let's interpret this + + align:start position:0% +so let's interpret this + + + align:start position:0% +so let's interpret this +and here's the interpretation i want to + + align:start position:0% +and here's the interpretation i want to + + + align:start position:0% +and here's the interpretation i want to +give you + + align:start position:0% +give you + + + align:start position:0% +give you +so in the absence so consider it + + align:start position:0% +so in the absence so consider it + + + align:start position:0% +so in the absence so consider it +classically consider classically the + + align:start position:0% +classically consider classically the + + + align:start position:0% +classically consider classically the +system classically we have + + align:start position:0% +system classically we have + + + align:start position:0% +system classically we have +an object + + align:start position:0% +an object + + + align:start position:0% +an object +with some energy and it comes along it + + align:start position:0% +with some energy and it comes along it + + + align:start position:0% +with some energy and it comes along it +rolls along and it finds a barrier a + + align:start position:0% +rolls along and it finds a barrier a + + + align:start position:0% +rolls along and it finds a barrier a +potential well and what happens when it + + align:start position:0% +potential well and what happens when it + + + align:start position:0% +potential well and what happens when it +gets into the potential well + + align:start position:0% +gets into the potential well + + + align:start position:0% +gets into the potential well +it speeds up + + align:start position:0% +it speeds up + + + align:start position:0% +it speeds up +right because it's got a lot more energy + + align:start position:0% +right because it's got a lot more energy + + + align:start position:0% +right because it's got a lot more energy +relative to the potential so it goes + + align:start position:0% +relative to the potential so it goes + + + align:start position:0% +relative to the potential so it goes +much faster in here and it gets to the + + align:start position:0% +much faster in here and it gets to the + + + align:start position:0% +much faster in here and it gets to the +other side it slows down again + + align:start position:0% +other side it slows down again + + + align:start position:0% +other side it slows down again +so if i had taken a particle with + + align:start position:0% +so if i had taken a particle with + + + align:start position:0% +so if i had taken a particle with +velocity and so let's call this position + + align:start position:0% +velocity and so let's call this position + + + align:start position:0% +velocity and so let's call this position +zero let's say it gets to this wall at + + align:start position:0% +zero let's say it gets to this wall at + + + align:start position:0% +zero let's say it gets to this wall at +time zero so it's moving with x is equal + + align:start position:0% +time zero so it's moving with x is equal + + + align:start position:0% +time zero so it's moving with x is equal +to v naught t + + align:start position:0% +to v naught t + + + align:start position:0% +to v naught t +if there had been no barrier there then + + align:start position:0% +if there had been no barrier there then + + + align:start position:0% +if there had been no barrier there then +at subsequent times it would get out + + align:start position:0% +at subsequent times it would get out + + + align:start position:0% +at subsequent times it would get out +here in a time + + align:start position:0% +here in a time + + + align:start position:0% +here in a time +x that distance over v naught right + + align:start position:0% +x that distance over v naught right + + + align:start position:0% +x that distance over v naught right +however imagine this well was + + align:start position:0% +however imagine this well was + + + align:start position:0% +however imagine this well was +extraordinarily deep + + align:start position:0% +extraordinarily deep + + + align:start position:0% +extraordinarily deep +if this well were extraordinarily deep + + align:start position:0% +if this well were extraordinarily deep + + + align:start position:0% +if this well were extraordinarily deep +what would happen + + align:start position:0% +what would happen + + + align:start position:0% +what would happen +well basically in here its velocity is + + align:start position:0% +well basically in here its velocity is + + + align:start position:0% +well basically in here its velocity is +arbitrarily large + + align:start position:0% +arbitrarily large + + + align:start position:0% +arbitrarily large +and it would just immediately jump + + align:start position:0% +and it would just immediately jump + + + align:start position:0% +and it would just immediately jump +across + + align:start position:0% +across + + + align:start position:0% +across +this well yeah + + align:start position:0% +this well yeah + + + align:start position:0% +this well yeah +so its velocity so this would be a + + align:start position:0% +so its velocity so this would be a + + + align:start position:0% +so its velocity so this would be a +perfectly good description of the of the + + align:start position:0% +perfectly good description of the of the + + + align:start position:0% +perfectly good description of the of the +motion before it gets to the well but + + align:start position:0% +motion before it gets to the well but + + + align:start position:0% +motion before it gets to the well but +after it leaves the well the position is + + align:start position:0% +after it leaves the well the position is + + + align:start position:0% +after it leaves the well the position is +going to be + + align:start position:0% +going to be + + + align:start position:0% +going to be +v naught t + + align:start position:0% + + + + align:start position:0% + +plus well what's the time shift it the + + align:start position:0% +plus well what's the time shift it the + + + align:start position:0% +plus well what's the time shift it the +time shift is the time that we didn't + + align:start position:0% +time shift is the time that we didn't + + + align:start position:0% +time shift is the time that we didn't +need to cross this gap + + align:start position:0% +need to cross this gap + + + align:start position:0% +need to cross this gap +and how much would that time have been + + align:start position:0% +and how much would that time have been + + + align:start position:0% +and how much would that time have been +that time would have been well it's the + + align:start position:0% +that time would have been well it's the + + + align:start position:0% +that time would have been well it's the +distance divided by the velocity + + align:start position:0% +distance divided by the velocity + + + align:start position:0% +distance divided by the velocity +right so that's the time we didn't need + + align:start position:0% +right so that's the time we didn't need + + + align:start position:0% +right so that's the time we didn't need +so t plus it moves as if it's at a later + + align:start position:0% +so t plus it moves as if it's at a later + + + align:start position:0% +so t plus it moves as if it's at a later +time t plus l over v naught + + align:start position:0% +time t plus l over v naught + + + align:start position:0% +time t plus l over v naught +cool + + align:start position:0% + + + + align:start position:0% + +so if we had a really deep well and we + + align:start position:0% +so if we had a really deep well and we + + + align:start position:0% +so if we had a really deep well and we +watched a particle move we would watch + + align:start position:0% +watched a particle move we would watch + + + align:start position:0% +watched a particle move we would watch +it move x naught x is v not t v not t v + + align:start position:0% +it move x naught x is v not t v not t v + + + align:start position:0% +it move x naught x is v not t v not t v +not t v naught t plus l over v v naught + + align:start position:0% +not t v naught t plus l over v v naught + + + align:start position:0% +not t v naught t plus l over v v naught +t plus over v okay + + align:start position:0% + + + + align:start position:0% + +so it's the time that we made up by + + align:start position:0% +so it's the time that we made up by + + + align:start position:0% +so it's the time that we made up by +being deep in the well so there's a + + align:start position:0% +being deep in the well so there's a + + + align:start position:0% +being deep in the well so there's a +classical picture because it goes faster + + align:start position:0% +classical picture because it goes faster + + + align:start position:0% +classical picture because it goes faster +inside + + align:start position:0% +inside + + + align:start position:0% +inside +so comparing these + + align:start position:0% +so comparing these + + + align:start position:0% +so comparing these +here we've done a calculation of the + + align:start position:0% +here we've done a calculation of the + + + align:start position:0% +here we've done a calculation of the +time shift due to + + align:start position:0% +time shift due to + + + align:start position:0% +time shift due to +the quantum particle quantum + + align:start position:0% +the quantum particle quantum + + + align:start position:0% +the quantum particle quantum +mechanically + + align:start position:0% +mechanically + + + align:start position:0% +mechanically +transverse transiting the potential well + + align:start position:0% +transverse transiting the potential well + + + align:start position:0% +transverse transiting the potential well +yeah so let's compare these + + align:start position:0% +yeah so let's compare these + + + align:start position:0% +yeah so let's compare these +the classical prediction this says the + + align:start position:0% +the classical prediction this says the + + + align:start position:0% +the classical prediction this says the +classical prediction is um the + + align:start position:0% +classical prediction is um the + + + align:start position:0% +classical prediction is um the +time it took delta t classical + + align:start position:0% +time it took delta t classical + + + align:start position:0% +time it took delta t classical +is equal to l over v naught + + align:start position:0% +is equal to l over v naught + + + align:start position:0% +is equal to l over v naught +and the question is is this the same so + + align:start position:0% +and the question is is this the same so + + + align:start position:0% +and the question is is this the same so +one way to phrase this question is is + + align:start position:0% +one way to phrase this question is is + + + align:start position:0% +one way to phrase this question is is +the same as h bar d phi d e + + align:start position:0% + + + + align:start position:0% + +evaluated at uh + + align:start position:0% + + + + align:start position:0% + +k naught + + align:start position:0% +k naught + + + align:start position:0% +k naught +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and + + align:start position:0% + + + + align:start position:0% + +from our results last time + + align:start position:0% +from our results last time + + + align:start position:0% +from our results last time +for the amplitude c over a + + align:start position:0% +for the amplitude c over a + + + align:start position:0% +for the amplitude c over a +we get that phi + + align:start position:0% +we get that phi + + + align:start position:0% +we get that phi +is equal to which is just the minus the + + align:start position:0% +is equal to which is just the minus the + + + align:start position:0% +is equal to which is just the minus the +uh the argument or the phase of c over a + + align:start position:0% +uh the argument or the phase of c over a + + + align:start position:0% +uh the argument or the phase of c over a +or of the transmission coefficient + + align:start position:0% +or of the transmission coefficient + + + align:start position:0% +or of the transmission coefficient +little transition amplitude little t + + align:start position:0% +little transition amplitude little t + + + align:start position:0% +little transition amplitude little t +phi turns out to be equal to k2 l + + align:start position:0% +phi turns out to be equal to k2 l + + + align:start position:0% +phi turns out to be equal to k2 l +minus arctan + + align:start position:0% + + + + align:start position:0% + +of k1 squared plus k2 squared + + align:start position:0% +of k1 squared plus k2 squared + + + align:start position:0% +of k1 squared plus k2 squared +over 2 k1 k2 + + align:start position:0% + + + + align:start position:0% + +tan + + align:start position:0% +tan + + + align:start position:0% +tan +of k2l okay + + align:start position:0% +of k2l okay + + + align:start position:0% +of k2l okay +i look at this and it doesn't tell me + + align:start position:0% +i look at this and it doesn't tell me + + + align:start position:0% +i look at this and it doesn't tell me +all that much it's a little bit + + align:start position:0% +all that much it's a little bit + + + align:start position:0% +all that much it's a little bit +bewildering so let's unpack this + + align:start position:0% +bewildering so let's unpack this + + + align:start position:0% +bewildering so let's unpack this +what we really want to know is is this + + align:start position:0% +what we really want to know is is this + + + align:start position:0% +what we really want to know is is this +close to the classical result + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so + + align:start position:0% +so + + + align:start position:0% +so +here's a quick way to check + + align:start position:0% +here's a quick way to check + + + align:start position:0% +here's a quick way to check +this is we know this expression is going + + align:start position:0% +this is we know this expression is going + + + align:start position:0% +this is we know this expression is going +to simplify near resonance where the + + align:start position:0% +to simplify near resonance where the + + + align:start position:0% +to simplify near resonance where the +sign vanishes so let's look just for + + align:start position:0% +sign vanishes so let's look just for + + + align:start position:0% +sign vanishes so let's look just for +simplicity near the resonance + + align:start position:0% +simplicity near the resonance + + + align:start position:0% +simplicity near the resonance +and in particular let's look near the + + align:start position:0% +and in particular let's look near the + + + align:start position:0% +and in particular let's look near the +resonance k2 l + + align:start position:0% +resonance k2 l + + + align:start position:0% +resonance k2 l +is equal to n pi + + align:start position:0% +is equal to n pi + + + align:start position:0% +is equal to n pi +then it turns out that a quick + + align:start position:0% +then it turns out that a quick + + + align:start position:0% +then it turns out that a quick +calculation gives you that h bar d phi d + + align:start position:0% +calculation gives you that h bar d phi d + + + align:start position:0% +calculation gives you that h bar d phi d +e + + align:start position:0% + + + + align:start position:0% + +at this value of k at that value of the + + align:start position:0% +at this value of k at that value of the + + + align:start position:0% +at this value of k at that value of the +energy + + align:start position:0% +energy + + + align:start position:0% +energy +goes as l + + align:start position:0% +goes as l + + + align:start position:0% +goes as l +over 2 v naught times 1 plus whoops 1 + + align:start position:0% +over 2 v naught times 1 plus whoops 1 + + + align:start position:0% +over 2 v naught times 1 plus whoops 1 +plus + + align:start position:0% +plus + + + align:start position:0% +plus +the energy + + align:start position:0% +the energy + + + align:start position:0% +the energy +over the depth of the well v naught now + + align:start position:0% +over the depth of the well v naught now + + + align:start position:0% +over the depth of the well v naught now +remember the classical approximation was + + align:start position:0% +remember the classical approximation was + + + align:start position:0% +remember the classical approximation was +l over v naught we just did this very + + align:start position:0% +l over v naught we just did this very + + + align:start position:0% +l over v naught we just did this very +quickly we did it assuming an + + align:start position:0% +quickly we did it assuming an + + + align:start position:0% +quickly we did it assuming an +arbitrarily deep well so v naught is + + align:start position:0% +arbitrarily deep well so v naught is + + + align:start position:0% +arbitrarily deep well so v naught is +arbitrarily larger in magnitude than e + + align:start position:0% +arbitrarily larger in magnitude than e + + + align:start position:0% +arbitrarily larger in magnitude than e +so this term is negligible so where we + + align:start position:0% +so this term is negligible so where we + + + align:start position:0% +so this term is negligible so where we +should compare that very simple naive + + align:start position:0% +should compare that very simple naive + + + align:start position:0% +should compare that very simple naive +classical result is here l over two v + + align:start position:0% +classical result is here l over two v + + + align:start position:0% +classical result is here l over two v +naught and what we see is that the + + align:start position:0% +naught and what we see is that the + + + align:start position:0% +naught and what we see is that the +quantum mechanical result + + align:start position:0% +quantum mechanical result + + + align:start position:0% +quantum mechanical result +gives a time shift which is down by a + + align:start position:0% +gives a time shift which is down by a + + + align:start position:0% +gives a time shift which is down by a +factor of two + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so what's going on well apparently the + + align:start position:0% +so what's going on well apparently the + + + align:start position:0% +so what's going on well apparently the +things slowed down inside + + align:start position:0% +things slowed down inside + + + align:start position:0% +things slowed down inside +the time the time that it's that it took + + align:start position:0% +the time the time that it's that it took + + + align:start position:0% +the time the time that it's that it took +us to cross was greater than you would + + align:start position:0% +us to cross was greater than you would + + + align:start position:0% +us to cross was greater than you would +have naively guessed by making it + + align:start position:0% +have naively guessed by making it + + + align:start position:0% +have naively guessed by making it +arbitrarily deep + + align:start position:0% +arbitrarily deep + + + align:start position:0% +arbitrarily deep +and we can + + align:start position:0% +and we can + + + align:start position:0% +and we can +make that a little more sharp by + + align:start position:0% +make that a little more sharp by + + + align:start position:0% +make that a little more sharp by +plotting as a function of e + + align:start position:0% +plotting as a function of e + + + align:start position:0% +plotting as a function of e +over v naught + + align:start position:0% + + + + align:start position:0% + +the uh the actual phase shift so the + + align:start position:0% +the uh the actual phase shift so the + + + align:start position:0% +the uh the actual phase shift so the +classical prediction if you do better + + align:start position:0% +classical prediction if you do better + + + align:start position:0% +classical prediction if you do better +job than saying it's infinitely deep the + + align:start position:0% +job than saying it's infinitely deep the + + + align:start position:0% +job than saying it's infinitely deep the +classical prediction looks something + + align:start position:0% +classical prediction looks something + + + align:start position:0% +classical prediction looks something +like this + + align:start position:0% + + + + align:start position:0% + +okay and this is for + + align:start position:0% +okay and this is for + + + align:start position:0% +okay and this is for +delta t + + align:start position:0% +delta t + + + align:start position:0% +delta t +the time shift classical + + align:start position:0% +the time shift classical + + + align:start position:0% +the time shift classical +when you look at the correct quantum + + align:start position:0% +when you look at the correct quantum + + + align:start position:0% +when you look at the correct quantum +mechanical result here's what you find + + align:start position:0% + + + + align:start position:0% + +oops + + align:start position:0% + + + + align:start position:0% + +where + + align:start position:0% + + + + align:start position:0% + +the + + align:start position:0% +the + + + align:start position:0% +the +difference is a factor of two + + align:start position:0% +difference is a factor of two + + + align:start position:0% +difference is a factor of two +one-half the height down and again + + align:start position:0% +one-half the height down and again + + + align:start position:0% +one-half the height down and again +one-half a height down so this is that + + align:start position:0% +one-half a height down so this is that + + + align:start position:0% +one-half a height down so this is that +factor of two downstairs + + align:start position:0% +factor of two downstairs + + + align:start position:0% +factor of two downstairs +so the wave packet goes actually a + + align:start position:0% +so the wave packet goes actually a + + + align:start position:0% +so the wave packet goes actually a +little bit faster than it would than the + + align:start position:0% +little bit faster than it would than the + + + align:start position:0% +little bit faster than it would than the +classical prediction would guess except + + align:start position:0% +classical prediction would guess except + + + align:start position:0% +classical prediction would guess except +near resonance and these are at the + + align:start position:0% +near resonance and these are at the + + + align:start position:0% +near resonance and these are at the +resonant values of the momentum + + align:start position:0% +resonant values of the momentum + + + align:start position:0% +resonant values of the momentum +at the resonant values of the momentum + + align:start position:0% +at the resonant values of the momentum + + + align:start position:0% +at the resonant values of the momentum +it takes much longer to get across + + align:start position:0% +it takes much longer to get across + + + align:start position:0% +it takes much longer to get across +instead of going a little bit faster + + align:start position:0% +instead of going a little bit faster + + + align:start position:0% +instead of going a little bit faster +than the classic result it goes a factor + + align:start position:0% +than the classic result it goes a factor + + + align:start position:0% +than the classic result it goes a factor +of two slower than the classical result + + align:start position:0% +of two slower than the classical result + + + align:start position:0% +of two slower than the classical result +and so now i ask you the question why is + + align:start position:0% +and so now i ask you the question why is + + + align:start position:0% +and so now i ask you the question why is +it going more slowly why does it spend + + align:start position:0% +it going more slowly why does it spend + + + align:start position:0% +it going more slowly why does it spend +so much more time inside the well + + align:start position:0% +so much more time inside the well + + + align:start position:0% +so much more time inside the well +quantum mechanically than it would have + + align:start position:0% +quantum mechanically than it would have + + + align:start position:0% +quantum mechanically than it would have +classically + + align:start position:0% +classically + + + align:start position:0% +classically +why is the particle effectively taking + + align:start position:0% +why is the particle effectively taking + + + align:start position:0% +why is the particle effectively taking +so much longer to transit the well near + + align:start position:0% +so much longer to transit the well near + + + align:start position:0% +so much longer to transit the well near +resonance + + align:start position:0% + + + + align:start position:0% + +yeah exactly so the classical particle + + align:start position:0% +yeah exactly so the classical particle + + + align:start position:0% +yeah exactly so the classical particle +just goes across the quantum mechanical + + align:start position:0% +just goes across the quantum mechanical + + + align:start position:0% +just goes across the quantum mechanical +particle has a superposition of + + align:start position:0% +particle has a superposition of + + + align:start position:0% +particle has a superposition of +contributions to its amplitude where it + + align:start position:0% +contributions to its amplitude where it + + + align:start position:0% +contributions to its amplitude where it +transits + + align:start position:0% +transits + + + align:start position:0% +transits +transit bounce bounce transit transit + + align:start position:0% +transit bounce bounce transit transit + + + align:start position:0% +transit bounce bounce transit transit +bounce bounce bounce bounce transit + + align:start position:0% +bounce bounce bounce bounce transit + + + align:start position:0% +bounce bounce bounce bounce transit +and now you can ask how much time was + + align:start position:0% +and now you can ask how much time was + + + align:start position:0% +and now you can ask how much time was +spent by each of those imaginary + + align:start position:0% +spent by each of those imaginary + + + align:start position:0% +spent by each of those imaginary +particles imaginarily moving across + + align:start position:0% +particles imaginarily moving across + + + align:start position:0% +particles imaginarily moving across +and if you're careful about how you set + + align:start position:0% +and if you're careful about how you set + + + align:start position:0% +and if you're careful about how you set +up that question you can recover this + + align:start position:0% +up that question you can recover this + + + align:start position:0% +up that question you can recover this +factor of two + + align:start position:0% +factor of two + + + align:start position:0% +factor of two +which is kind of beautiful + + align:start position:0% +which is kind of beautiful + + + align:start position:0% +which is kind of beautiful +but the important thing here is when + + align:start position:0% +but the important thing here is when + + + align:start position:0% +but the important thing here is when +you're hitting resonance the multiple + + align:start position:0% +you're hitting resonance the multiple + + + align:start position:0% +you're hitting resonance the multiple +scattering processes are important + + align:start position:0% +scattering processes are important + + + align:start position:0% +scattering processes are important +they're not canceling out they're not at + + align:start position:0% +they're not canceling out they're not at + + + align:start position:0% +they're not canceling out they're not at +random phase they're not interfering + + align:start position:0% +random phase they're not interfering + + + align:start position:0% +random phase they're not interfering +destructively with each other they're + + align:start position:0% +destructively with each other they're + + + align:start position:0% +destructively with each other they're +interfering constructively and you get + + align:start position:0% +interfering constructively and you get + + + align:start position:0% +interfering constructively and you get +perfect transmission precisely because + + align:start position:0% +perfect transmission precisely because + + + align:start position:0% +perfect transmission precisely because +of the + + align:start position:0% +of the + + + align:start position:0% +of the +constructive interference of an infinite + + align:start position:0% +constructive interference of an infinite + + + align:start position:0% +constructive interference of an infinite +number of contributions to the quantum + + align:start position:0% +number of contributions to the quantum + + + align:start position:0% +number of contributions to the quantum +mechanical amplitude okay and this is + + align:start position:0% +mechanical amplitude okay and this is + + + align:start position:0% +mechanical amplitude okay and this is +again we're seeing the same thing in + + align:start position:0% +again we're seeing the same thing in + + + align:start position:0% +again we're seeing the same thing in +this annoying slowdown + + align:start position:0% +this annoying slowdown + + + align:start position:0% +this annoying slowdown +and this tells us another thing though + + align:start position:0% +and this tells us another thing though + + + align:start position:0% +and this tells us another thing though +which is that the phase the scattering + + align:start position:0% +which is that the phase the scattering + + + align:start position:0% +which is that the phase the scattering +phase the phase in the transmission + + align:start position:0% +phase the phase in the transmission + + + align:start position:0% +phase the phase in the transmission +amplitude + + align:start position:0% +amplitude + + + align:start position:0% +amplitude +contains an awful lot of the physics of + + align:start position:0% +contains an awful lot of the physics of + + + align:start position:0% +contains an awful lot of the physics of +the system it's telling us about + + align:start position:0% +the system it's telling us about + + + align:start position:0% +the system it's telling us about +how long it takes for the wave packet to + + align:start position:0% +how long it takes for the wave packet to + + + align:start position:0% +how long it takes for the wave packet to +transit across the potential effectively + + align:start position:0% +transit across the potential effectively + + + align:start position:0% +transit across the potential effectively +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +sorry the vertical axis here is the time + + align:start position:0% +sorry the vertical axis here is the time + + + align:start position:0% +sorry the vertical axis here is the time +that it takes the the shift in the time + + align:start position:0% +that it takes the the shift in the time + + + align:start position:0% +that it takes the the shift in the time +due to the fact that it went across this + + align:start position:0% +due to the fact that it went across this + + + align:start position:0% +due to the fact that it went across this +well and went a little bit faster inside + + align:start position:0% +well and went a little bit faster inside + + + align:start position:0% +well and went a little bit faster inside +okay so empirically what it means is + + align:start position:0% +okay so empirically what it means is + + + align:start position:0% +okay so empirically what it means is +when you get out very far away + + align:start position:0% +when you get out very far away + + + align:start position:0% +when you get out very far away +and you watch the velocity the motion of + + align:start position:0% +and you watch the velocity the motion of + + + align:start position:0% +and you watch the velocity the motion of +the wave packet and you ask how long has + + align:start position:0% +the wave packet and you ask how long has + + + align:start position:0% +the wave packet and you ask how long has +it been since it + + align:start position:0% +it been since it + + + align:start position:0% +it been since it +got to the barrier in the first place it + + align:start position:0% +got to the barrier in the first place it + + + align:start position:0% +got to the barrier in the first place it +took less time than you would have + + align:start position:0% +took less time than you would have + + + align:start position:0% +took less time than you would have +guessed by knowing that its velocity is + + align:start position:0% +guessed by knowing that its velocity is + + + align:start position:0% +guessed by knowing that its velocity is +v naught and the amount of time less is + + align:start position:0% +v naught and the amount of time less is + + + align:start position:0% +v naught and the amount of time less is +this much time + + align:start position:0% +this much time + + + align:start position:0% +this much time +that answer your question good + + align:start position:0% + + + + align:start position:0% + +of uh one yeah + + align:start position:0% + + + + align:start position:0% + +it bounces around twice + + align:start position:0% +it bounces around twice + + + align:start position:0% +it bounces around twice +um + + align:start position:0% +um + + + align:start position:0% +um +uh so so the the classical amplitude is + + align:start position:0% +uh so so the the classical amplitude is + + + align:start position:0% +uh so so the the classical amplitude is +so when we compare the classical length + + align:start position:0% +so when we compare the classical length + + + align:start position:0% +so when we compare the classical length +to the limit that v naught goes to + + align:start position:0% +to the limit that v naught goes to + + + align:start position:0% +to the limit that v naught goes to +infinity + + align:start position:0% +infinity + + + align:start position:0% +infinity +so the the comparison is just a factor + + align:start position:0% +so the the comparison is just a factor + + + align:start position:0% +so the the comparison is just a factor +of two + + align:start position:0% +of two + + + align:start position:0% +of two +okay it's more complicated out here and + + align:start position:0% +okay it's more complicated out here and + + + align:start position:0% +okay it's more complicated out here and +i guess it's not it's it in the limit + + align:start position:0% +i guess it's not it's it in the limit + + + align:start position:0% +i guess it's not it's it in the limit +that v naught is large this is exactly + + align:start position:0% +that v naught is large this is exactly + + + align:start position:0% +that v naught is large this is exactly +one half + + align:start position:0% + + + + align:start position:0% + +well it's got the yeah it's got the the + + align:start position:0% +well it's got the yeah it's got the the + + + align:start position:0% +well it's got the yeah it's got the the +resonances are leading to this extra + + align:start position:0% +resonances are leading to this extra + + + align:start position:0% +resonances are leading to this extra +factor of one half um and so as you i i + + align:start position:0% +factor of one half um and so as you i i + + + align:start position:0% +factor of one half um and so as you i i +don't i have to say i don't remember + + align:start position:0% +don't i have to say i don't remember + + + align:start position:0% +don't i have to say i don't remember +exactly whether as you um include the + + align:start position:0% +exactly whether as you um include the + + + align:start position:0% +exactly whether as you um include the +the subleading terms of one over v + + align:start position:0% +the subleading terms of one over v + + + align:start position:0% +the subleading terms of one over v +naught whether it stays one half or + + align:start position:0% +naught whether it stays one half or + + + align:start position:0% +naught whether it stays one half or +whether it doesn't but in the limit that + + align:start position:0% +whether it doesn't but in the limit that + + + align:start position:0% +whether it doesn't but in the limit that +v naught is large it remains either + + align:start position:0% +v naught is large it remains either + + + align:start position:0% +v naught is large it remains either +close to one half or exactly one if i + + align:start position:0% +close to one half or exactly one if i + + + align:start position:0% +close to one half or exactly one if i +just don't remember exactly the + + align:start position:0% +just don't remember exactly the + + + align:start position:0% +just don't remember exactly the +important thing is that there's a sharp + + align:start position:0% +important thing is that there's a sharp + + + align:start position:0% +important thing is that there's a sharp +dip + + align:start position:0% +dip + + + align:start position:0% +dip +it takes much longer to transit and so + + align:start position:0% +it takes much longer to transit and so + + + align:start position:0% +it takes much longer to transit and so +you get less + + align:start position:0% +you get less + + + align:start position:0% +you get less +bonus time as it were + + align:start position:0% +bonus time as it were + + + align:start position:0% +bonus time as it were +uh you've you've gained less time in the + + align:start position:0% +uh you've you've gained less time in the + + + align:start position:0% +uh you've you've gained less time in the +quantum mechanical model than the + + align:start position:0% +quantum mechanical model than the + + + align:start position:0% +quantum mechanical model than the +classical model + + align:start position:0% +classical model + + + align:start position:0% +classical model +and when you do the experiment you get + + align:start position:0% +and when you do the experiment you get + + + align:start position:0% +and when you do the experiment you get +the quantum result right so + + align:start position:0% + + + + align:start position:0% + +that's uh that's the crucial point + + align:start position:0% +that's uh that's the crucial point + + + align:start position:0% +that's uh that's the crucial point +other questions + + align:start position:0% +other questions + + + align:start position:0% +other questions +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so the phase contains an awful lot of + + align:start position:0% +so the phase contains an awful lot of + + + align:start position:0% +so the phase contains an awful lot of +the physics + + align:start position:0% + + + + align:start position:0% + +so i want to generalize this whole story + + align:start position:0% + + + + align:start position:0% + +in a very particular way + + align:start position:0% +in a very particular way + + + align:start position:0% +in a very particular way +and this way of reorganizing the + + align:start position:0% +and this way of reorganizing the + + + align:start position:0% +and this way of reorganizing the +scattering in 1d so what we're doing + + align:start position:0% +scattering in 1d so what we're doing + + + align:start position:0% +scattering in 1d so what we're doing +right now is we're studying scattering + + align:start position:0% +right now is we're studying scattering + + + align:start position:0% +right now is we're studying scattering +problems in one dimension but we live in + + align:start position:0% +problems in one dimension but we live in + + + align:start position:0% +problems in one dimension but we live in +three dimensions the story's going to be + + align:start position:0% +three dimensions the story's going to be + + + align:start position:0% +three dimensions the story's going to be +more complicated in three dimensions + + align:start position:0% +more complicated in three dimensions + + + align:start position:0% +more complicated in three dimensions +it's going to be more complicated in two + + align:start position:0% +it's going to be more complicated in two + + + align:start position:0% +it's going to be more complicated in two +dimensions but the basic ideas are all + + align:start position:0% +dimensions but the basic ideas are all + + + align:start position:0% +dimensions but the basic ideas are all +the same + + align:start position:0% +the same + + + align:start position:0% +the same +it's just the details are going to be + + align:start position:0% +it's just the details are going to be + + + align:start position:0% +it's just the details are going to be +different and one thing that turns out + + align:start position:0% +different and one thing that turns out + + + align:start position:0% +different and one thing that turns out +to be very useful in organizing + + align:start position:0% +to be very useful in organizing + + + align:start position:0% +to be very useful in organizing +scattering both in + + align:start position:0% +scattering both in + + + align:start position:0% +scattering both in +in one dimension and in three dimensions + + align:start position:0% +in one dimension and in three dimensions + + + align:start position:0% +in one dimension and in three dimensions +something called the scattering matrix + + align:start position:0% +something called the scattering matrix + + + align:start position:0% +something called the scattering matrix +and i'm going to talk about that now + + align:start position:0% +and i'm going to talk about that now + + + align:start position:0% +and i'm going to talk about that now +in three dimensions it's almost i mean + + align:start position:0% +in three dimensions it's almost i mean + + + align:start position:0% +in three dimensions it's almost i mean +it's essential + + align:start position:0% +it's essential + + + align:start position:0% +it's essential +but even in one dimensions where it's + + align:start position:0% +but even in one dimensions where it's + + + align:start position:0% +but even in one dimensions where it's +usually not used it's a very powerful + + align:start position:0% +usually not used it's a very powerful + + + align:start position:0% +usually not used it's a very powerful +way to organize our knowledge of the + + align:start position:0% +way to organize our knowledge of the + + + align:start position:0% +way to organize our knowledge of the +system as encoded by the scattering data + + align:start position:0% +system as encoded by the scattering data + + + align:start position:0% +system as encoded by the scattering data +so here's the basic idea + + align:start position:0% +so here's the basic idea + + + align:start position:0% +so here's the basic idea +as we discussed before what we really + + align:start position:0% +as we discussed before what we really + + + align:start position:0% +as we discussed before what we really +want to do in the ideal world is take + + align:start position:0% +want to do in the ideal world is take + + + align:start position:0% +want to do in the ideal world is take +some unknown potential in some bounded + + align:start position:0% +some unknown potential in some bounded + + + align:start position:0% +some unknown potential in some bounded +region + + align:start position:0% +region + + + align:start position:0% +region +some region and outside we have the + + align:start position:0% +some region and outside we have the + + + align:start position:0% +some region and outside we have the +potential is constant + + align:start position:0% +potential is constant + + + align:start position:0% +potential is constant +modula my bad artistic skills so + + align:start position:0% +modula my bad artistic skills so + + + align:start position:0% +modula my bad artistic skills so +potential is constant out here + + align:start position:0% + + + + align:start position:0% + +and the potential could be some horrible + + align:start position:0% +and the potential could be some horrible + + + align:start position:0% +and the potential could be some horrible +thing in here that we don't happen to + + align:start position:0% +thing in here that we don't happen to + + + align:start position:0% +thing in here that we don't happen to +know and we want to read off of the + + align:start position:0% +know and we want to read off of the + + + align:start position:0% +know and we want to read off of the +scattering process we want to be able to + + align:start position:0% +scattering process we want to be able to + + + align:start position:0% +scattering process we want to be able to +do something about the potential so for + + align:start position:0% +do something about the potential so for + + + align:start position:0% +do something about the potential so for +example we can deduce the um the uh the + + align:start position:0% +example we can deduce the um the uh the + + + align:start position:0% +example we can deduce the um the uh the +energy of our step + + align:start position:0% +energy of our step + + + align:start position:0% +energy of our step +um or + + align:start position:0% +um or + + + align:start position:0% +um or +we can deduce the energy by looking so + + align:start position:0% +we can deduce the energy by looking so + + + align:start position:0% +we can deduce the energy by looking so +good we can reduce the energy by looking + + align:start position:0% +good we can reduce the energy by looking + + + align:start position:0% +good we can reduce the energy by looking +at the um + + align:start position:0% +at the um + + + align:start position:0% +at the um +the position of the barriers and we can + + align:start position:0% +the position of the barriers and we can + + + align:start position:0% +the position of the barriers and we can +disentangle the position of the energy + + align:start position:0% +disentangle the position of the energy + + + align:start position:0% +disentangle the position of the energy +and the uh the width the depth and the + + align:start position:0% +and the uh the width the depth and the + + + align:start position:0% +and the uh the width the depth and the +width by looking at the phase shift by + + align:start position:0% +width by looking at the phase shift by + + + align:start position:0% +width by looking at the phase shift by +looking at the time delay so we can + + align:start position:0% +looking at the time delay so we can + + + align:start position:0% +looking at the time delay so we can +deduce all the parameters of our + + align:start position:0% +deduce all the parameters of our + + + align:start position:0% +deduce all the parameters of our +potential by looking at the resonance + + align:start position:0% +potential by looking at the resonance + + + align:start position:0% +potential by looking at the resonance +points and the phase shifts i want to do + + align:start position:0% +points and the phase shifts i want to do + + + align:start position:0% +points and the phase shifts i want to do +this more generally for a general + + align:start position:0% +this more generally for a general + + + align:start position:0% +this more generally for a general +potential + + align:start position:0% +potential + + + align:start position:0% +potential +and to set that up we need to be a bit + + align:start position:0% +and to set that up we need to be a bit + + + align:start position:0% +and to set that up we need to be a bit +more general than than we've been + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so in general if we solve this potential + + align:start position:0% +so in general if we solve this potential + + + align:start position:0% +so in general if we solve this potential +as we talked about before we have a and + + align:start position:0% +as we talked about before we have a and + + + align:start position:0% +as we talked about before we have a and +d oh sorry a plus b + + align:start position:0% +d oh sorry a plus b + + + align:start position:0% +d oh sorry a plus b +i e to the i k x + + align:start position:0% +i e to the i k x + + + align:start position:0% +i e to the i k x +minus i k x out here + + align:start position:0% +minus i k x out here + + + align:start position:0% +minus i k x out here +and out here we have c e to the i k x + + align:start position:0% +and out here we have c e to the i k x + + + align:start position:0% +and out here we have c e to the i k x +and d e to the minus sign + + align:start position:0% + + + + align:start position:0% + +and i'm not going to ask what happens + + align:start position:0% +and i'm not going to ask what happens + + + align:start position:0% +and i'm not going to ask what happens +inside + + align:start position:0% + + + + align:start position:0% + +now we can do as discuss two kinds of + + align:start position:0% +now we can do as discuss two kinds of + + + align:start position:0% +now we can do as discuss two kinds of +scattering experiments we can send + + align:start position:0% +scattering experiments we can send + + + align:start position:0% +scattering experiments we can send +things in from the left in which case a + + align:start position:0% +things in from the left in which case a + + + align:start position:0% +things in from the left in which case a +is non-zero and then things can either + + align:start position:0% +is non-zero and then things can either + + + align:start position:0% +is non-zero and then things can either +transmit or reflect but nothing's going + + align:start position:0% +transmit or reflect but nothing's going + + + align:start position:0% +transmit or reflect but nothing's going +to come in from infinity so d is zero or + + align:start position:0% +to come in from infinity so d is zero or + + + align:start position:0% +to come in from infinity so d is zero or +we could do the same in reverse send + + align:start position:0% +we could do the same in reverse send + + + align:start position:0% +we could do the same in reverse send +things in from here and that corresponds + + align:start position:0% +things in from here and that corresponds + + + align:start position:0% +things in from here and that corresponds +to a zero nothing coming in this way + + align:start position:0% +to a zero nothing coming in this way + + + align:start position:0% +to a zero nothing coming in this way +but d non-zero + + align:start position:0% +but d non-zero + + + align:start position:0% +but d non-zero +and more generally we can ask the + + align:start position:0% +and more generally we can ask the + + + align:start position:0% +and more generally we can ask the +following question look suppose i send + + align:start position:0% +following question look suppose i send + + + align:start position:0% +following question look suppose i send +some amount of stuff in from the left + + align:start position:0% +some amount of stuff in from the left + + + align:start position:0% +some amount of stuff in from the left +and i send some amount of stuff in from + + align:start position:0% +and i send some amount of stuff in from + + + align:start position:0% +and i send some amount of stuff in from +the right d + + align:start position:0% +the right d + + + align:start position:0% +the right d +then that will tell me how much stuff + + align:start position:0% +then that will tell me how much stuff + + + align:start position:0% +then that will tell me how much stuff +will be going out to the right and how + + align:start position:0% +will be going out to the right and how + + + align:start position:0% +will be going out to the right and how +much stuff will be going out to the left + + align:start position:0% +much stuff will be going out to the left + + + align:start position:0% +much stuff will be going out to the left +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +if you tell me how much is coming in i + + align:start position:0% +if you tell me how much is coming in i + + + align:start position:0% +if you tell me how much is coming in i +will tell you how much is coming out + + align:start position:0% +will tell you how much is coming out + + + align:start position:0% +will tell you how much is coming out +bc + + align:start position:0% + + + + align:start position:0% + +so if you could solve this problem + + align:start position:0% +so if you could solve this problem + + + align:start position:0% +so if you could solve this problem +the answer is just some relation some + + align:start position:0% +the answer is just some relation some + + + align:start position:0% +the answer is just some relation some +pair of linear relations between these + + align:start position:0% +pair of linear relations between these + + + align:start position:0% +pair of linear relations between these +and we can write this as a matrix which + + align:start position:0% +and we can write this as a matrix which + + + align:start position:0% +and we can write this as a matrix which +i will call s11 s12 s21 + + align:start position:0% +i will call s11 s12 s21 + + + align:start position:0% +i will call s11 s12 s21 +s22 + + align:start position:0% +s22 + + + align:start position:0% +s22 +okay what this matrix is doing is it + + align:start position:0% +okay what this matrix is doing is it + + + align:start position:0% +okay what this matrix is doing is it +takes the amplitude you're sending in + + align:start position:0% +takes the amplitude you're sending in + + + align:start position:0% +takes the amplitude you're sending in +from the left or right and tells you the + + align:start position:0% +from the left or right and tells you the + + + align:start position:0% +from the left or right and tells you the +amplitude coming out to the left or to + + align:start position:0% +amplitude coming out to the left or to + + + align:start position:0% +amplitude coming out to the left or to +the right yes + + align:start position:0% +the right yes + + + align:start position:0% +the right yes +how would we know this relation is + + align:start position:0% +how would we know this relation is + + + align:start position:0% +how would we know this relation is +linear + + align:start position:0% +linear + + + align:start position:0% +linear +uh if you double the amount of stuff + + align:start position:0% +uh if you double the amount of stuff + + + align:start position:0% +uh if you double the amount of stuff +coming in + + align:start position:0% +coming in + + + align:start position:0% +coming in +then you must double the amount of stuff + + align:start position:0% +then you must double the amount of stuff + + + align:start position:0% +then you must double the amount of stuff +going out or probability is not + + align:start position:0% +going out or probability is not + + + align:start position:0% +going out or probability is not +conserved + + align:start position:0% + + + + align:start position:0% + +also we've derived these relations you + + align:start position:0% +also we've derived these relations you + + + align:start position:0% +also we've derived these relations you +know how the relations work the + + align:start position:0% +know how the relations work the + + + align:start position:0% +know how the relations work the +relations work by satisfying a series of + + align:start position:0% +relations work by satisfying a series of + + + align:start position:0% +relations work by satisfying a series of +linear equations uh + + align:start position:0% +linear equations uh + + + align:start position:0% +linear equations uh +between the various coefficients such + + align:start position:0% +between the various coefficients such + + + align:start position:0% +between the various coefficients such +that you have continuity and + + align:start position:0% +that you have continuity and + + + align:start position:0% +that you have continuity and +differentiability at all the matching + + align:start position:0% +differentiability at all the matching + + + align:start position:0% +differentiability at all the matching +points + + align:start position:0% +points + + + align:start position:0% +points +but the crucial thing of linearity is + + align:start position:0% +but the crucial thing of linearity is + + + align:start position:0% +but the crucial thing of linearity is +you need probabilities conserved and + + align:start position:0% +you need probabilities conserved and + + + align:start position:0% +you need probabilities conserved and +time evolution is linear so + + align:start position:0% +time evolution is linear so + + + align:start position:0% +time evolution is linear so +other questions + + align:start position:0% +other questions + + + align:start position:0% +other questions +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so this is just some stupid matrix and + + align:start position:0% +so this is just some stupid matrix and + + + align:start position:0% +so this is just some stupid matrix and +we call it not surprisingly the s matrix + + align:start position:0% +we call it not surprisingly the s matrix + + + align:start position:0% +we call it not surprisingly the s matrix +in all of its majesty um + + align:start position:0% +in all of its majesty um + + + align:start position:0% +in all of its majesty um +and + + align:start position:0% +and + + + align:start position:0% +and +the basic idea is this for scattering + + align:start position:0% +the basic idea is this for scattering + + + align:start position:0% +the basic idea is this for scattering +problems if you if someone tells you the + + align:start position:0% +problems if you if someone tells you the + + + align:start position:0% +problems if you if someone tells you the +s matrix and in particular if someone + + align:start position:0% +s matrix and in particular if someone + + + align:start position:0% +s matrix and in particular if someone +tells you how all the coefficients of + + align:start position:0% +tells you how all the coefficients of + + + align:start position:0% +tells you how all the coefficients of +the s matrix vary with energy + + align:start position:0% +the s matrix vary with energy + + + align:start position:0% +the s matrix vary with energy +then you've completely solved any + + align:start position:0% +then you've completely solved any + + + align:start position:0% +then you've completely solved any +scattering problem you tell me what a + + align:start position:0% +scattering problem you tell me what a + + + align:start position:0% +scattering problem you tell me what a +and d are great i'll tell you exactly + + align:start position:0% +and d are great i'll tell you exactly + + + align:start position:0% +and d are great i'll tell you exactly +what b and c are mode by mode and i can + + align:start position:0% +what b and c are mode by mode and i can + + + align:start position:0% +what b and c are mode by mode and i can +do this for a superposition so this + + align:start position:0% +do this for a superposition so this + + + align:start position:0% +do this for a superposition so this +allows you to completely solve + + align:start position:0% +allows you to completely solve + + + align:start position:0% +allows you to completely solve +any scattering problem in quantum + + align:start position:0% +any scattering problem in quantum + + + align:start position:0% +any scattering problem in quantum +mechanics once you know it so it + + align:start position:0% +mechanics once you know it so it + + + align:start position:0% +mechanics once you know it so it +suffices to know s to solve all + + align:start position:0% +suffices to know s to solve all + + + align:start position:0% +suffices to know s to solve all +scattering problems + + align:start position:0% + + + + align:start position:0% + +so let's i want to now spend just a + + align:start position:0% +so let's i want to now spend just a + + + align:start position:0% +so let's i want to now spend just a +little bit of time thinking about what + + align:start position:0% +little bit of time thinking about what + + + align:start position:0% +little bit of time thinking about what +properties the s matrix and its + + align:start position:0% +properties the s matrix and its + + + align:start position:0% +properties the s matrix and its +components must satisfy + + align:start position:0% +components must satisfy + + + align:start position:0% +components must satisfy +what things what properties must the s + + align:start position:0% +what things what properties must the s + + + align:start position:0% +what things what properties must the s +matrix satisfy in order to uh + + align:start position:0% +matrix satisfy in order to uh + + + align:start position:0% +matrix satisfy in order to uh +you know jive well with the rest of the + + align:start position:0% +you know jive well with the rest of the + + + align:start position:0% +you know jive well with the rest of the +rules of quantum mechanics + + align:start position:0% +rules of quantum mechanics + + + align:start position:0% +rules of quantum mechanics +and i'm not going to study any + + align:start position:0% +and i'm not going to study any + + + align:start position:0% +and i'm not going to study any +particular system i just want to ask + + align:start position:0% +particular system i just want to ask + + + align:start position:0% +particular system i just want to ask +general questions + + align:start position:0% +general questions + + + align:start position:0% +general questions +so the first thing that must be true is + + align:start position:0% +so the first thing that must be true is + + + align:start position:0% +so the first thing that must be true is +that stuff + + align:start position:0% +that stuff + + + align:start position:0% +that stuff +doesn't just doesn't disappear + + align:start position:0% + + + + align:start position:0% + +i guess disapperate it's probably the + + align:start position:0% +i guess disapperate it's probably the + + + align:start position:0% +i guess disapperate it's probably the +appropriate + + align:start position:0% +appropriate + + + align:start position:0% +appropriate +so + + align:start position:0% +so + + + align:start position:0% +so +stuff doesn't + + align:start position:0% +stuff doesn't + + + align:start position:0% +stuff doesn't +leak out of the world so whatever goes + + align:start position:0% +leak out of the world so whatever goes + + + align:start position:0% +leak out of the world so whatever goes +in must come out so what that means is + + align:start position:0% +in must come out so what that means is + + + align:start position:0% +in must come out so what that means is +norm of a squared plus norm of d squared + + align:start position:0% +norm of a squared plus norm of d squared + + + align:start position:0% +norm of a squared plus norm of d squared +which is the probability density in + + align:start position:0% +which is the probability density in + + + align:start position:0% +which is the probability density in +probe and probability density out must + + align:start position:0% +probe and probability density out must + + + align:start position:0% +probe and probability density out must +be equal to + + align:start position:0% +be equal to + + + align:start position:0% +be equal to +b squared plus c squared + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +everyone agree with that + + align:start position:0% + + + + align:start position:0% + +uh + + align:start position:0% +uh + + + align:start position:0% +uh +why can't stuff stay in the potential + + align:start position:0% +why can't stuff stay in the potential + + + align:start position:0% +why can't stuff stay in the potential +that's a good ques so um + + align:start position:0% + + + + align:start position:0% + +so yeah it's so it's a stationary state + + align:start position:0% +so yeah it's so it's a stationary state + + + align:start position:0% +so yeah it's so it's a stationary state +is so if we're looking at at fixed + + align:start position:0% +is so if we're looking at at fixed + + + align:start position:0% +is so if we're looking at at fixed +energy eigenstates we know that we're in + + align:start position:0% +energy eigenstates we know that we're in + + + align:start position:0% +energy eigenstates we know that we're in +a stationary state so whatever the + + align:start position:0% +a stationary state so whatever the + + + align:start position:0% +a stationary state so whatever the +amplitude um going into the middle is it + + align:start position:0% +amplitude um going into the middle is it + + + align:start position:0% +amplitude um going into the middle is it +must also be coming out of the middle + + align:start position:0% +must also be coming out of the middle + + + align:start position:0% +must also be coming out of the middle +right so there's another way to say this + + align:start position:0% +right so there's another way to say this + + + align:start position:0% +right so there's another way to say this +which is that um let's think about it + + align:start position:0% +which is that um let's think about it + + + align:start position:0% +which is that um let's think about it +not in terms of energy individual energy + + align:start position:0% +not in terms of energy individual energy + + + align:start position:0% +not in terms of energy individual energy +i can say so let's think about it in + + align:start position:0% +i can say so let's think about it in + + + align:start position:0% +i can say so let's think about it in +terms of wave packets so if we take a + + align:start position:0% +terms of wave packets so if we take a + + + align:start position:0% +terms of wave packets so if we take a +wave packet of stuff and we send in that + + align:start position:0% +wave packet of stuff and we send in that + + + align:start position:0% +wave packet of stuff and we send in that +wave packet it has some momentum right + + align:start position:0% + + + + align:start position:0% + +um oh this is going to get delicate + + align:start position:0% +um oh this is going to get delicate + + + align:start position:0% +um oh this is going to get delicate +technical let me just stick with the + + align:start position:0% +technical let me just stick with the + + + align:start position:0% +technical let me just stick with the +first + + align:start position:0% +first + + + align:start position:0% +first +the first statement which is that if + + align:start position:0% +the first statement which is that if + + + align:start position:0% +the first statement which is that if +stuff is going in then it has to also be + + align:start position:0% +stuff is going in then it has to also be + + + align:start position:0% +stuff is going in then it has to also be +coming out + + align:start position:0% +coming out + + + align:start position:0% +coming out +by the fact that this is an energy + + align:start position:0% +by the fact that this is an energy + + + align:start position:0% +by the fact that this is an energy +eigenstate + + align:start position:0% +eigenstate + + + align:start position:0% +eigenstate +the overall probability distribution is + + align:start position:0% +the overall probability distribution is + + + align:start position:0% +the overall probability distribution is +not changing in time + + align:start position:0% + + + + align:start position:0% + +so if if stuff went in and it didn't + + align:start position:0% +so if if stuff went in and it didn't + + + align:start position:0% +so if if stuff went in and it didn't +come out that would mean it's staying + + align:start position:0% +come out that would mean it's staying + + + align:start position:0% +come out that would mean it's staying +there that would mean that the + + align:start position:0% +there that would mean that the + + + align:start position:0% +there that would mean that the +probability density is changing in time + + align:start position:0% +probability density is changing in time + + + align:start position:0% +probability density is changing in time +that's not what happens in an energy + + align:start position:0% +that's not what happens in an energy + + + align:start position:0% +that's not what happens in an energy +eigenstate the probability distribution + + align:start position:0% +eigenstate the probability distribution + + + align:start position:0% +eigenstate the probability distribution +is time independent + + align:start position:0% +is time independent + + + align:start position:0% +is time independent +everyone call that + + align:start position:0% +everyone call that + + + align:start position:0% +everyone call that +okay so + + align:start position:0% +okay so + + + align:start position:0% +okay so +um + + align:start position:0% + + + + align:start position:0% + +good so uh so let's think though about + + align:start position:0% +good so uh so let's think though about + + + align:start position:0% +good so uh so let's think though about +what this is i can write this in the + + align:start position:0% +what this is i can write this in the + + + align:start position:0% +what this is i can write this in the +following nice way + + align:start position:0% +following nice way + + + align:start position:0% +following nice way +i can write this as uh a complex + + align:start position:0% +i can write this as uh a complex + + + align:start position:0% +i can write this as uh a complex +conjugate + + align:start position:0% +conjugate + + + align:start position:0% +conjugate +d complex con whoops d complex conjugate + + align:start position:0% +d complex con whoops d complex conjugate + + + align:start position:0% +d complex con whoops d complex conjugate +a d + + align:start position:0% +a d + + + align:start position:0% +a d +and on the right hand side this is equal + + align:start position:0% +and on the right hand side this is equal + + + align:start position:0% +and on the right hand side this is equal +to uh b complex conjugate c complex + + align:start position:0% +to uh b complex conjugate c complex + + + align:start position:0% +to uh b complex conjugate c complex +conjugate + + align:start position:0% +conjugate + + + align:start position:0% +conjugate +bc + + align:start position:0% +bc + + + align:start position:0% +bc +i have done nothing other than write + + align:start position:0% +i have done nothing other than write + + + align:start position:0% +i have done nothing other than write +this out in some suggested form + + align:start position:0% +this out in some suggested form + + + align:start position:0% +this out in some suggested form +but + + align:start position:0% +but + + + align:start position:0% +but +b and c are equal to the s matrix so bc + + align:start position:0% +b and c are equal to the s matrix so bc + + + align:start position:0% +b and c are equal to the s matrix so bc +is the s matrix times a + + align:start position:0% +is the s matrix times a + + + align:start position:0% +is the s matrix times a +and b comics conjugate c complex + + align:start position:0% +and b comics conjugate c complex + + + align:start position:0% +and b comics conjugate c complex +conjugate is the transpose complex + + align:start position:0% +conjugate is the transpose complex + + + align:start position:0% +conjugate is the transpose complex +conjugate so this is equal to + + align:start position:0% +conjugate so this is equal to + + + align:start position:0% +conjugate so this is equal to +a complex conjugate d complex conjugate + + align:start position:0% +a complex conjugate d complex conjugate + + + align:start position:0% +a complex conjugate d complex conjugate +s transpose complex conjugate also known + + align:start position:0% +s transpose complex conjugate also known + + + align:start position:0% +s transpose complex conjugate also known +as adjoint and this is s on a d + + align:start position:0% + + + + align:start position:0% + +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +but this has to be equal to this + + align:start position:0% +but this has to be equal to this + + + align:start position:0% +but this has to be equal to this +for any a and d + + align:start position:0% +for any a and d + + + align:start position:0% +for any a and d +so what must be true of s dagger s as a + + align:start position:0% +so what must be true of s dagger s as a + + + align:start position:0% +so what must be true of s dagger s as a +matrix + + align:start position:0% +matrix + + + align:start position:0% +matrix +it's got to be the identity + + align:start position:0% + + + + align:start position:0% + +as a matrix in order for this to be true + + align:start position:0% +as a matrix in order for this to be true + + + align:start position:0% +as a matrix in order for this to be true +for all a and e + + align:start position:0% +for all a and e + + + align:start position:0% +for all a and e +ah that's cool stuff doesn't disappear s + + align:start position:0% +ah that's cool stuff doesn't disappear s + + + align:start position:0% +ah that's cool stuff doesn't disappear s +is a unitary matrix + + align:start position:0% + + + + align:start position:0% + +so s is unitary matrix + + align:start position:0% + + + + align:start position:0% + +its inverse is its adjoint + + align:start position:0% +its inverse is its adjoint + + + align:start position:0% +its inverse is its adjoint +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and you'll prove this in a little more + + align:start position:0% +and you'll prove this in a little more + + + align:start position:0% +and you'll prove this in a little more +um + + align:start position:0% +um + + + align:start position:0% +um +uh elegance um + + align:start position:0% +uh elegance um + + + align:start position:0% +uh elegance um +you'll + + align:start position:0% +you'll + + + align:start position:0% +you'll +you'll study this in a little more + + align:start position:0% +you'll study this in a little more + + + align:start position:0% +you'll study this in a little more +detail on the problem set you showed uh + + align:start position:0% +detail on the problem set you showed uh + + + align:start position:0% +detail on the problem set you showed uh +the definition of unitary you studied + + align:start position:0% +the definition of unitary you studied + + + align:start position:0% +the definition of unitary you studied +the definition of unitary and the last + + align:start position:0% +the definition of unitary and the last + + + align:start position:0% +the definition of unitary and the last +problem is that + + align:start position:0% +problem is that + + + align:start position:0% +problem is that +okay so that's the first thing about s + + align:start position:0% +okay so that's the first thing about s + + + align:start position:0% +okay so that's the first thing about s +and it turns out to be completely + + align:start position:0% +and it turns out to be completely + + + align:start position:0% +and it turns out to be completely +general any time whether you're in one + + align:start position:0% +general any time whether you're in one + + + align:start position:0% +general any time whether you're in one +dimension or two dimension or three if + + align:start position:0% +dimension or two dimension or three if + + + align:start position:0% +dimension or two dimension or three if +you send stuff in it should not get + + align:start position:0% +you send stuff in it should not get + + + align:start position:0% +you send stuff in it should not get +stuck it should come out + + align:start position:0% +stuck it should come out + + + align:start position:0% +stuck it should come out +and when it does come out + + align:start position:0% +and when it does come out + + + align:start position:0% +and when it does come out +uh the statement that it comes out for + + align:start position:0% +uh the statement that it comes out for + + + align:start position:0% +uh the statement that it comes out for +energy eigenstates is the statement that + + align:start position:0% +energy eigenstates is the statement that + + + align:start position:0% +energy eigenstates is the statement that +s is unitary matrix + + align:start position:0% +s is unitary matrix + + + align:start position:0% +s is unitary matrix +questions on that + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +a consequence of that + + align:start position:0% + + + + align:start position:0% + +is that the the eigenvalues + + align:start position:0% + + + + align:start position:0% + +of s + + align:start position:0% +of s + + + align:start position:0% +of s +are phases + + align:start position:0% +are phases + + + align:start position:0% +are phases +pure phases + + align:start position:0% + + + + align:start position:0% + +so i can write s + + align:start position:0% + + + + align:start position:0% + +i'll write them as + + align:start position:0% +i'll write them as + + + align:start position:0% +i'll write them as +s1 + + align:start position:0% +s1 + + + align:start position:0% +s1 +e to the i uh phi 1 and + + align:start position:0% +e to the i uh phi 1 and + + + align:start position:0% +e to the i uh phi 1 and +s2 is equal to i phi 2. + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +the statement that s is a unitary matrix + + align:start position:0% +the statement that s is a unitary matrix + + + align:start position:0% +the statement that s is a unitary matrix +leads to constraints on the coefficients + + align:start position:0% +leads to constraints on the coefficients + + + align:start position:0% +leads to constraints on the coefficients +okay and you're going to derive these on + + align:start position:0% +okay and you're going to derive these on + + + align:start position:0% +okay and you're going to derive these on +your problem set i'm just going to list + + align:start position:0% +your problem set i'm just going to list + + + align:start position:0% +your problem set i'm just going to list +them now so the first is that the + + align:start position:0% +them now so the first is that the + + + align:start position:0% +them now so the first is that the +magnitude of s1 + + align:start position:0% +magnitude of s1 + + + align:start position:0% +magnitude of s1 +1 is equal to the magnitude of s22 + + align:start position:0% +1 is equal to the magnitude of s22 + + + align:start position:0% +1 is equal to the magnitude of s22 +the magnitude of s12 is equal to the + + align:start position:0% +the magnitude of s12 is equal to the + + + align:start position:0% +the magnitude of s12 is equal to the +magnitude of s21 + + align:start position:0% + + + + align:start position:0% + +oops + + align:start position:0% + + + + align:start position:0% + +good + + align:start position:0% +good + + + align:start position:0% +good +and + + align:start position:0% +and + + + align:start position:0% +and +more importantly s12 norm squared plus s + + align:start position:0% +more importantly s12 norm squared plus s + + + align:start position:0% +more importantly s12 norm squared plus s +one one squared + + align:start position:0% +one one squared + + + align:start position:0% +one one squared +is equal to one + + align:start position:0% +is equal to one + + + align:start position:0% +is equal to one +and finally s11 + + align:start position:0% +and finally s11 + + + align:start position:0% +and finally s11 +s2 s12 + + align:start position:0% +s2 s12 + + + align:start position:0% +s2 s12 +complex conjugate plus + + align:start position:0% +complex conjugate plus + + + align:start position:0% +complex conjugate plus +two one s two two complex conjugate uh + + align:start position:0% +two one s two two complex conjugate uh + + + align:start position:0% +two one s two two complex conjugate uh +is equal to zero + + align:start position:0% +is equal to zero + + + align:start position:0% +is equal to zero +so + + align:start position:0% + + + + align:start position:0% + +what do these mean what are these + + align:start position:0% +what do these mean what are these + + + align:start position:0% +what do these mean what are these +conditions telling us + + align:start position:0% + + + + align:start position:0% + +what are these can so they're they're + + align:start position:0% +what are these can so they're they're + + + align:start position:0% +what are these can so they're they're +telling us of course they're a + + align:start position:0% +telling us of course they're a + + + align:start position:0% +telling us of course they're a +consequence of conservation of + + align:start position:0% +consequence of conservation of + + + align:start position:0% +consequence of conservation of +probability but they have another + + align:start position:0% +probability but they have another + + + align:start position:0% +probability but they have another +meaning and let's to get that other + + align:start position:0% +meaning and let's to get that other + + + align:start position:0% +meaning and let's to get that other +meaning let's look at the definition of + + align:start position:0% +meaning let's look at the definition of + + + align:start position:0% +meaning let's look at the definition of +of + + align:start position:0% +of + + + align:start position:0% +of +uh the transmission amplitudes so in + + align:start position:0% +uh the transmission amplitudes so in + + + align:start position:0% +uh the transmission amplitudes so in +particular consider the case that we + + align:start position:0% +particular consider the case that we + + + align:start position:0% +particular consider the case that we +send stuff in from the left + + align:start position:0% +send stuff in from the left + + + align:start position:0% +send stuff in from the left +and nothing in from the right so that + + align:start position:0% +and nothing in from the right so that + + + align:start position:0% +and nothing in from the right so that +corresponds to d equals zero so when d + + align:start position:0% +corresponds to d equals zero so when d + + + align:start position:0% +corresponds to d equals zero so when d +equals zero what does this tell us it + + align:start position:0% +equals zero what does this tell us it + + + align:start position:0% +equals zero what does this tell us it +tells us that b + + align:start position:0% +tells us that b + + + align:start position:0% +tells us that b +is equal to and a equals one for + + align:start position:0% +is equal to and a equals one for + + + align:start position:0% +is equal to and a equals one for +normalization so + + align:start position:0% +normalization so + + + align:start position:0% +normalization so +b is equal to + + align:start position:0% +b is equal to + + + align:start position:0% +b is equal to +well d is equal to zero so it's just s11 + + align:start position:0% +well d is equal to zero so it's just s11 + + + align:start position:0% +well d is equal to zero so it's just s11 +a + + align:start position:0% +a + + + align:start position:0% +a +so b over a + + align:start position:0% +so b over a + + + align:start position:0% +so b over a +is s11 + + align:start position:0% +is s11 + + + align:start position:0% +is s11 +and similarly c over a + + align:start position:0% +and similarly c over a + + + align:start position:0% +and similarly c over a +is s21 + + align:start position:0% +is s21 + + + align:start position:0% +is s21 +but c over a is the thing that we've + + align:start position:0% +but c over a is the thing that we've + + + align:start position:0% +but c over a is the thing that we've +been calling + + align:start position:0% +been calling + + + align:start position:0% +been calling +the transmission amplitude little t + + align:start position:0% +the transmission amplitude little t + + + align:start position:0% +the transmission amplitude little t +and this is the reflection amplitude + + align:start position:0% +and this is the reflection amplitude + + + align:start position:0% +and this is the reflection amplitude +little r so this is the reflection + + align:start position:0% +little r so this is the reflection + + + align:start position:0% +little r so this is the reflection +amplitude if we send in stuff and + + align:start position:0% +amplitude if we send in stuff and + + + align:start position:0% +amplitude if we send in stuff and +bounces off reflex to the left + + align:start position:0% +bounces off reflex to the left + + + align:start position:0% +bounces off reflex to the left +and this is the transmission amplitude + + align:start position:0% +and this is the transmission amplitude + + + align:start position:0% +and this is the transmission amplitude +for transmitting to the right + + align:start position:0% + + + + align:start position:0% + +everyone cool with that + + align:start position:0% +everyone cool with that + + + align:start position:0% +everyone cool with that +and by the same token so this is + + align:start position:0% +and by the same token so this is + + + align:start position:0% +and by the same token so this is +reflection to the left this is + + align:start position:0% +reflection to the left this is + + + align:start position:0% +reflection to the left this is +transmission to the right + + align:start position:0% +transmission to the right + + + align:start position:0% +transmission to the right +by the same token this is going to be + + align:start position:0% +by the same token this is going to be + + + align:start position:0% +by the same token this is going to be +transmission to the left and reflection + + align:start position:0% +transmission to the left and reflection + + + align:start position:0% +transmission to the left and reflection +to the right + + align:start position:0% + + + + align:start position:0% + +so now let's look at these conditions + + align:start position:0% +so now let's look at these conditions + + + align:start position:0% +so now let's look at these conditions +s11 is reflection this is going to be + + align:start position:0% +s11 is reflection this is going to be + + + align:start position:0% +s11 is reflection this is going to be +reflection this says that the reflection + + align:start position:0% +reflection this says that the reflection + + + align:start position:0% +reflection this says that the reflection +to the left is equal to the reflection + + align:start position:0% +to the left is equal to the reflection + + + align:start position:0% +to the left is equal to the reflection +to the right + + align:start position:0% +to the right + + + align:start position:0% +to the right +in magnitude + + align:start position:0% + + + + align:start position:0% + +before what we saw was for the simple + + align:start position:0% +before what we saw was for the simple + + + align:start position:0% +before what we saw was for the simple +step the reflection was equal to the + + align:start position:0% +step the reflection was equal to the + + + align:start position:0% +step the reflection was equal to the +reflection the reflection amplitude was + + align:start position:0% +reflection the reflection amplitude was + + + align:start position:0% +reflection the reflection amplitude was +equal from left to right not just the + + align:start position:0% +equal from left to right not just the + + + align:start position:0% +equal from left to right not just the +magnitude but the actual value was equal + + align:start position:0% +magnitude but the actual value was equal + + + align:start position:0% +magnitude but the actual value was equal +from the left and the right it was a + + align:start position:0% +from the left and the right it was a + + + align:start position:0% +from the left and the right it was a +little bit of a cheat because they were + + align:start position:0% +little bit of a cheat because they were + + + align:start position:0% +little bit of a cheat because they were +real + + align:start position:0% + + + + align:start position:0% + +and we saw that that was a consequence + + align:start position:0% +and we saw that that was a consequence + + + align:start position:0% +and we saw that that was a consequence +of just being the step we didn't know + + align:start position:0% +of just being the step we didn't know + + + align:start position:0% +of just being the step we didn't know +anything more about it but now we see + + align:start position:0% +anything more about it but now we see + + + align:start position:0% +anything more about it but now we see +that on general grounds on conservation + + align:start position:0% +that on general grounds on conservation + + + align:start position:0% +that on general grounds on conservation +and probability grounds + + align:start position:0% +and probability grounds + + + align:start position:0% +and probability grounds +the magnitude of the reflection to the + + align:start position:0% +the magnitude of the reflection to the + + + align:start position:0% +the magnitude of the reflection to the +left and to the right for any potential + + align:start position:0% +left and to the right for any potential + + + align:start position:0% +left and to the right for any potential +had better be equal and similarly the + + align:start position:0% +had better be equal and similarly the + + + align:start position:0% +had better be equal and similarly the +magnitude of the transmission for the + + align:start position:0% +magnitude of the transmission for the + + + align:start position:0% +magnitude of the transmission for the +left + + align:start position:0% +left + + + align:start position:0% +left +and the transmission to the right + + align:start position:0% +and the transmission to the right + + + align:start position:0% +and the transmission to the right +had better be equal + + align:start position:0% +had better be equal + + + align:start position:0% +had better be equal +all other things being + + align:start position:0% +all other things being + + + align:start position:0% +all other things being +uh you know if you're sending in from + + align:start position:0% +uh you know if you're sending in from + + + align:start position:0% +uh you know if you're sending in from +the left and then transmitting to the + + align:start position:0% +the left and then transmitting to the + + + align:start position:0% +the left and then transmitting to the +left or sending in from the right and + + align:start position:0% +left or sending in from the right and + + + align:start position:0% +left or sending in from the right and +transmitting to the right and what does + + align:start position:0% +transmitting to the right and what does + + + align:start position:0% +transmitting to the right and what does +this one tell us + + align:start position:0% +this one tell us + + + align:start position:0% +this one tell us +well s12 and s11 + + align:start position:0% +well s12 and s11 + + + align:start position:0% +well s12 and s11 +that tells us that t squared little t + + align:start position:0% +that tells us that t squared little t + + + align:start position:0% +that tells us that t squared little t +squared which is + + align:start position:0% +squared which is + + + align:start position:0% +squared which is +the total probability trans to transmit + + align:start position:0% +the total probability trans to transmit + + + align:start position:0% +the total probability trans to transmit +plus little r squared norm squared is + + align:start position:0% +plus little r squared norm squared is + + + align:start position:0% +plus little r squared norm squared is +the total probability to reflect is + + align:start position:0% +the total probability to reflect is + + + align:start position:0% +the total probability to reflect is +equal to one and we saw this last time + + align:start position:0% +equal to one and we saw this last time + + + align:start position:0% +equal to one and we saw this last time +too + + align:start position:0% + + + + align:start position:0% + +and this was the earlier definition of + + align:start position:0% +and this was the earlier definition of + + + align:start position:0% +and this was the earlier definition of +nothing gets stuck + + align:start position:0% +nothing gets stuck + + + align:start position:0% +nothing gets stuck +and this one + + align:start position:0% +and this one + + + align:start position:0% +and this one +you'll study on your problem set + + align:start position:0% +you'll study on your problem set + + + align:start position:0% +you'll study on your problem set +it's a little more subtle + + align:start position:0% + + + + align:start position:0% + +okay questions + + align:start position:0% +okay questions + + + align:start position:0% +okay questions +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +one more time + + align:start position:0% + + + + align:start position:0% + +yeah i got s's okay good so the way we + + align:start position:0% +yeah i got s's okay good so the way we + + + align:start position:0% +yeah i got s's okay good so the way we +got s was unitary first off this is just + + align:start position:0% +got s was unitary first off this is just + + + align:start position:0% +got s was unitary first off this is just +the definition of s s is the matrix that + + align:start position:0% +the definition of s s is the matrix that + + + align:start position:0% +the definition of s s is the matrix that +g for any energy relates a and d the in + + align:start position:0% +g for any energy relates a and d the in + + + align:start position:0% +g for any energy relates a and d the in +going amplitudes to the outgoing + + align:start position:0% +going amplitudes to the outgoing + + + align:start position:0% +going amplitudes to the outgoing +amplitudes b and c just the definition + + align:start position:0% +amplitudes b and c just the definition + + + align:start position:0% +amplitudes b and c just the definition +meanwhile i claim that stuff doesn't go + + align:start position:0% +meanwhile i claim that stuff doesn't go + + + align:start position:0% +meanwhile i claim that stuff doesn't go +away nothing gets stuck nothing gets + + align:start position:0% +away nothing gets stuck nothing gets + + + align:start position:0% +away nothing gets stuck nothing gets +nothing disappears so the total + + align:start position:0% +nothing disappears so the total + + + align:start position:0% +nothing disappears so the total +probability density of stuff going in + + align:start position:0% +probability density of stuff going in + + + align:start position:0% +probability density of stuff going in +must be equal to the total probability + + align:start position:0% +must be equal to the total probability + + + align:start position:0% +must be equal to the total probability +density of stuff going out + + align:start position:0% +density of stuff going out + + + align:start position:0% +density of stuff going out +but the probability this + + align:start position:0% +but the probability this + + + align:start position:0% +but the probability this +the probability of stuff going in can be + + align:start position:0% +the probability of stuff going in can be + + + align:start position:0% +the probability of stuff going in can be +expressed as this + + align:start position:0% +expressed as this + + + align:start position:0% +expressed as this +row vector times this column vector and + + align:start position:0% +row vector times this column vector and + + + align:start position:0% +row vector times this column vector and +on the out this row vector times this + + align:start position:0% +on the out this row vector times this + + + align:start position:0% +on the out this row vector times this +column vector and now we use the + + align:start position:0% +column vector and now we use the + + + align:start position:0% +column vector and now we use the +definition of the s matrix this column + + align:start position:0% +definition of the s matrix this column + + + align:start position:0% +definition of the s matrix this column +vector is equal to s times this row + + align:start position:0% +vector is equal to s times this row + + + align:start position:0% +vector is equal to s times this row +vector + + align:start position:0% +vector + + + align:start position:0% +vector +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +b c is equal to s times a d + + align:start position:0% +b c is equal to s times a d + + + align:start position:0% +b c is equal to s times a d +and when i take the transpose complex + + align:start position:0% +and when i take the transpose complex + + + align:start position:0% +and when i take the transpose complex +conjugate i get a d transpose complex + + align:start position:0% +conjugate i get a d transpose complex + + + align:start position:0% +conjugate i get a d transpose complex +conjugate s transpose complex conjugate + + align:start position:0% +conjugate s transpose complex conjugate + + + align:start position:0% +conjugate s transpose complex conjugate +but that's yes adjoint + + align:start position:0% +but that's yes adjoint + + + align:start position:0% +but that's yes adjoint +but in order for this to be true for any + + align:start position:0% +but in order for this to be true for any + + + align:start position:0% +but in order for this to be true for any +matrix any vectors a and d + + align:start position:0% +matrix any vectors a and d + + + align:start position:0% +matrix any vectors a and d +this must be it must be that as stagger + + align:start position:0% +this must be it must be that as stagger + + + align:start position:0% +this must be it must be that as stagger +s is the unitary is the identity but + + align:start position:0% +s is the unitary is the identity but + + + align:start position:0% +s is the unitary is the identity but +that's the definition of a unitary + + align:start position:0% +that's the definition of a unitary + + + align:start position:0% +that's the definition of a unitary +matrix + + align:start position:0% +matrix + + + align:start position:0% +matrix +cool + + align:start position:0% +cool + + + align:start position:0% +cool +others + + align:start position:0% +others + + + align:start position:0% +others +okay + + align:start position:0% + + + + align:start position:0% + +you're going to prove a variety of + + align:start position:0% +you're going to prove a variety of + + + align:start position:0% +you're going to prove a variety of +things on the problem set + + align:start position:0% +things on the problem set + + + align:start position:0% +things on the problem set +about + + align:start position:0% +about + + + align:start position:0% +about +the um + + align:start position:0% +the um + + + align:start position:0% +the um +about the scattering matrix and its + + align:start position:0% +about the scattering matrix and its + + + align:start position:0% +about the scattering matrix and its +coefficients but i want to show you two + + align:start position:0% +coefficients but i want to show you two + + + align:start position:0% +coefficients but i want to show you two +properties of it + + align:start position:0% + + + + align:start position:0% + +the first + + align:start position:0% +the first + + + align:start position:0% +the first +is + + align:start position:0% +is + + + align:start position:0% +is +reasonably tame + + align:start position:0% +reasonably tame + + + align:start position:0% +reasonably tame +and it'll make a little sharper the step + + align:start position:0% +and it'll make a little sharper the step + + + align:start position:0% +and it'll make a little sharper the step +result we got earlier that the + + align:start position:0% +result we got earlier that the + + + align:start position:0% +result we got earlier that the +reflection in both directions off the + + align:start position:0% +reflection in both directions off the + + + align:start position:0% +reflection in both directions off the +step potential is in fact exactly the + + align:start position:0% +step potential is in fact exactly the + + + align:start position:0% +step potential is in fact exactly the +same + + align:start position:0% +same + + + align:start position:0% +same +so + + align:start position:0% +so + + + align:start position:0% +so +where did i put this + + align:start position:0% +where did i put this + + + align:start position:0% +where did i put this +good so suppose + + align:start position:0% + + + + align:start position:0% + +suppose our system is time reversal + + align:start position:0% +suppose our system is time reversal + + + align:start position:0% +suppose our system is time reversal +invariant + + align:start position:0% + + + + align:start position:0% + +so if t goes to minus t nothing changes + + align:start position:0% +so if t goes to minus t nothing changes + + + align:start position:0% +so if t goes to minus t nothing changes +this would not be true for example if we + + align:start position:0% +this would not be true for example if we + + + align:start position:0% +this would not be true for example if we +had electric currents in our system + + align:start position:0% +had electric currents in our system + + + align:start position:0% +had electric currents in our system +because as we take t to minus t then the + + align:start position:0% +because as we take t to minus t then the + + + align:start position:0% +because as we take t to minus t then the +current reverses so if their current + + align:start position:0% +current reverses so if their current + + + align:start position:0% +current reverses so if their current +shows up in the potential or if a + + align:start position:0% +shows up in the potential or if a + + + align:start position:0% +shows up in the potential or if a +magnetic field due to a current shows up + + align:start position:0% +magnetic field due to a current shows up + + + align:start position:0% +magnetic field due to a current shows up +in the potential energy then as we + + align:start position:0% +in the potential energy then as we + + + align:start position:0% +in the potential energy then as we +change t to minus t we change the + + align:start position:0% +change t to minus t we change the + + + align:start position:0% +change t to minus t we change the +direction of the current we change the + + align:start position:0% +direction of the current we change the + + + align:start position:0% +direction of the current we change the +direction of the magnetic field + + align:start position:0% +direction of the magnetic field + + + align:start position:0% +direction of the magnetic field +so in simple systems where we have time + + align:start position:0% +so in simple systems where we have time + + + align:start position:0% +so in simple systems where we have time +reversal invariants + + align:start position:0% +reversal invariants + + + align:start position:0% +reversal invariants +for example electrostatics but not for + + align:start position:0% +for example electrostatics but not for + + + align:start position:0% +for example electrostatics but not for +example magnetostatics suppose we have + + align:start position:0% +example magnetostatics suppose we have + + + align:start position:0% +example magnetostatics suppose we have +time reversal and variance + + align:start position:0% +time reversal and variance + + + align:start position:0% +time reversal and variance +then + + align:start position:0% +then + + + align:start position:0% +then +what you've shown on a previous problem + + align:start position:0% +what you've shown on a previous problem + + + align:start position:0% +what you've shown on a previous problem +set is that psi is a solution + + align:start position:0% +set is that psi is a solution + + + align:start position:0% +set is that psi is a solution +then psi star psi complex conjugate is + + align:start position:0% +then psi star psi complex conjugate is + + + align:start position:0% +then psi star psi complex conjugate is +also a solution + + align:start position:0% + + + + align:start position:0% + +and using these + + align:start position:0% +and using these + + + align:start position:0% +and using these +what you'll what you can show and i'm + + align:start position:0% +what you'll what you can show and i'm + + + align:start position:0% +what you'll what you can show and i'm +not going to go through the steps for + + align:start position:0% +not going to go through the steps for + + + align:start position:0% +not going to go through the steps for +this + + align:start position:0% +this + + + align:start position:0% +this +well okay that's easy so + + align:start position:0% +well okay that's easy so + + + align:start position:0% +well okay that's easy so +if we do the time reversal the wave + + align:start position:0% +if we do the time reversal the wave + + + align:start position:0% +if we do the time reversal the wave +function + + align:start position:0% +function + + + align:start position:0% +function +on looking on the left or on the right + + align:start position:0% +on looking on the left or on the right + + + align:start position:0% +on looking on the left or on the right +so comparing these guys um so what + + align:start position:0% +so comparing these guys um so what + + + align:start position:0% +so comparing these guys um so what +changes + + align:start position:0% +changes + + + align:start position:0% +changes +well under time reversal + + align:start position:0% +well under time reversal + + + align:start position:0% +well under time reversal +we get a solution so given this solution + + align:start position:0% +we get a solution so given this solution + + + align:start position:0% +we get a solution so given this solution +we have another solution a star e to the + + align:start position:0% +we have another solution a star e to the + + + align:start position:0% +we have another solution a star e to the +minus i k x b star e to the plus i k x + + align:start position:0% +minus i k x b star e to the plus i k x + + + align:start position:0% +minus i k x b star e to the plus i k x +see minus + + align:start position:0% +see minus + + + align:start position:0% +see minus +star + + align:start position:0% +star + + + align:start position:0% +star +star + + align:start position:0% +star + + + align:start position:0% +star +plus + + align:start position:0% +plus + + + align:start position:0% +plus +okay so we can run exactly the same game + + align:start position:0% +okay so we can run exactly the same game + + + align:start position:0% +okay so we can run exactly the same game +now with this + + align:start position:0% +now with this + + + align:start position:0% +now with this +amplitude + + align:start position:0% + + + + align:start position:0% + +and when you put these conditions when + + align:start position:0% +and when you put these conditions when + + + align:start position:0% +and when you put these conditions when +you put the conditions together which + + align:start position:0% +you put the conditions together which + + + align:start position:0% +you put the conditions together which +you'll do on the problem set um so this + + align:start position:0% +you'll do on the problem set um so this + + + align:start position:0% +you'll do on the problem set um so this +another way to say this is the same + + align:start position:0% +another way to say this is the same + + + align:start position:0% +another way to say this is the same +solution with k to minus k and with a + + align:start position:0% +solution with k to minus k and with a + + + align:start position:0% +solution with k to minus k and with a +and b ex replaced by their complex + + align:start position:0% +and b ex replaced by their complex + + + align:start position:0% +and b ex replaced by their complex +conjugates and c and d replaced by each + + align:start position:0% +conjugates and c and d replaced by each + + + align:start position:0% +conjugates and c and d replaced by each +other's complex conjugates + + align:start position:0% +other's complex conjugates + + + align:start position:0% +other's complex conjugates +then this implies that it must be true + + align:start position:0% +then this implies that it must be true + + + align:start position:0% +then this implies that it must be true +that + + align:start position:0% +that + + + align:start position:0% +that +a + + align:start position:0% +a + + + align:start position:0% +a +uh + + align:start position:0% +uh + + + align:start position:0% +uh +and d which are now the outgoing guys + + align:start position:0% +and d which are now the outgoing guys + + + align:start position:0% +and d which are now the outgoing guys +because we've time reversed is equal to + + align:start position:0% +because we've time reversed is equal to + + + align:start position:0% +because we've time reversed is equal to +s and i'll write this out explicitly + + align:start position:0% +s and i'll write this out explicitly + + + align:start position:0% +s and i'll write this out explicitly +s11 s12 s21 s22 + + align:start position:0% + + + + align:start position:0% + +b star + + align:start position:0% +b star + + + align:start position:0% +b star +and c star + + align:start position:0% +and c star + + + align:start position:0% +and c star +okay and so these together give you that + + align:start position:0% + + + + align:start position:0% + +i should have done this over here + + align:start position:0% +i should have done this over here + + + align:start position:0% +i should have done this over here +therefore + + align:start position:0% +therefore + + + align:start position:0% +therefore +s complex conjugate s + + align:start position:0% +s complex conjugate s + + + align:start position:0% +s complex conjugate s +is equal to one + + align:start position:0% + + + + align:start position:0% + +okay so if s complex conjugate s is + + align:start position:0% +okay so if s complex conjugate s is + + + align:start position:0% +okay so if s complex conjugate s is +equal to one then s inverse is equal to + + align:start position:0% +equal to one then s inverse is equal to + + + align:start position:0% +equal to one then s inverse is equal to +s transpose + + align:start position:0% + + + + align:start position:0% + +just putting this on the right + + align:start position:0% +just putting this on the right + + + align:start position:0% +just putting this on the right +so s transpose is equal to s inverse + + align:start position:0% +so s transpose is equal to s inverse + + + align:start position:0% +so s transpose is equal to s inverse +is equal to s adjoint + + align:start position:0% +is equal to s adjoint + + + align:start position:0% +is equal to s adjoint +because s is also unitary + + align:start position:0% + + + + align:start position:0% + +so time reversal and variance + + align:start position:0% + + + + align:start position:0% + +implies for example that s is equal to + + align:start position:0% +implies for example that s is equal to + + + align:start position:0% +implies for example that s is equal to +whoops um + + align:start position:0% +whoops um + + + align:start position:0% +whoops um +uh + + align:start position:0% +uh + + + align:start position:0% +uh +that s dagger is equal to s r s is equal + + align:start position:0% +that s dagger is equal to s r s is equal + + + align:start position:0% +that s dagger is equal to s r s is equal +to s transpose + + align:start position:0% + + + + align:start position:0% + +stem reverse + + align:start position:0% +stem reverse + + + align:start position:0% +stem reverse +this is what i wanted to write here it + + align:start position:0% +this is what i wanted to write here it + + + align:start position:0% +this is what i wanted to write here it +gives us that s is equal to s transpose + + align:start position:0% +gives us that s is equal to s transpose + + + align:start position:0% +gives us that s is equal to s transpose +and in particular this tells us that s21 + + align:start position:0% +and in particular this tells us that s21 + + + align:start position:0% +and in particular this tells us that s21 +is equal to s12 + + align:start position:0% +is equal to s12 + + + align:start position:0% +is equal to s12 +the off diagonal terms are + + align:start position:0% +the off diagonal terms are + + + align:start position:0% +the off diagonal terms are +equal + + align:start position:0% +equal + + + align:start position:0% +equal +not just in magnitude which was insured + + align:start position:0% +not just in magnitude which was insured + + + align:start position:0% +not just in magnitude which was insured +by unitarity but if in addition to uh to + + align:start position:0% +by unitarity but if in addition to uh to + + + align:start position:0% +by unitarity but if in addition to uh to +being a unitary system which of course + + align:start position:0% +being a unitary system which of course + + + align:start position:0% +being a unitary system which of course +it should be if in addition it's time + + align:start position:0% +it should be if in addition it's time + + + align:start position:0% +it should be if in addition it's time +reversal invariant then we see that the + + align:start position:0% +reversal invariant then we see that the + + + align:start position:0% +reversal invariant then we see that the +off-diagonal terms are equal not just in + + align:start position:0% +off-diagonal terms are equal not just in + + + align:start position:0% +off-diagonal terms are equal not just in +magnitude but also in phase and as you + + align:start position:0% +magnitude but also in phase and as you + + + align:start position:0% +magnitude but also in phase and as you +know the phase is important the phase + + align:start position:0% +know the phase is important the phase + + + align:start position:0% +know the phase is important the phase +contains physics it tells you about time + + align:start position:0% +contains physics it tells you about time + + + align:start position:0% +contains physics it tells you about time +delays and shifts on in the scattering + + align:start position:0% +delays and shifts on in the scattering + + + align:start position:0% +delays and shifts on in the scattering +process so the phases are the same that + + align:start position:0% +process so the phases are the same that + + + align:start position:0% +process so the phases are the same that +statement is not a trivial one it + + align:start position:0% +statement is not a trivial one it + + + align:start position:0% +statement is not a trivial one it +contains physics + + align:start position:0% +contains physics + + + align:start position:0% +contains physics +so when the system is time reversal + + align:start position:0% +so when the system is time reversal + + + align:start position:0% +so when the system is time reversal +invariant the phases are the the phases + + align:start position:0% +invariant the phases are the the phases + + + align:start position:0% +invariant the phases are the the phases +as well as the amplitudes are the same + + align:start position:0% +as well as the amplitudes are the same + + + align:start position:0% +as well as the amplitudes are the same +and you'll derive a series of related + + align:start position:0% +and you'll derive a series of related + + + align:start position:0% +and you'll derive a series of related +conditions or consequences + + align:start position:0% + + + + align:start position:0% + +for the s matrix from various properties + + align:start position:0% +for the s matrix from various properties + + + align:start position:0% +for the s matrix from various properties +of the system for example parity if you + + align:start position:0% +of the system for example parity if you + + + align:start position:0% +of the system for example parity if you +can if you have a symmetric potential + + align:start position:0% +can if you have a symmetric potential + + + align:start position:0% +can if you have a symmetric potential +but now i want to in the last few + + align:start position:0% +but now i want to in the last few + + + align:start position:0% +but now i want to in the last few +minutes i just want to tell you a really + + align:start position:0% +minutes i just want to tell you a really + + + align:start position:0% +minutes i just want to tell you a really +lovely thing + + align:start position:0% +lovely thing + + + align:start position:0% +lovely thing +so it should be pretty clear at this + + align:start position:0% +so it should be pretty clear at this + + + align:start position:0% +so it should be pretty clear at this +point that all the information about + + align:start position:0% +point that all the information about + + + align:start position:0% +point that all the information about +scattering is contained in the s matrix + + align:start position:0% +scattering is contained in the s matrix + + + align:start position:0% +scattering is contained in the s matrix +and its dependence on the energy if you + + align:start position:0% +and its dependence on the energy if you + + + align:start position:0% +and its dependence on the energy if you +know what the incident amplitudes are + + align:start position:0% +know what the incident amplitudes are + + + align:start position:0% +know what the incident amplitudes are +you know what the outgoing amplitudes + + align:start position:0% +you know what the outgoing amplitudes + + + align:start position:0% +you know what the outgoing amplitudes +are + + align:start position:0% +are + + + align:start position:0% +are +and that's cool because you can measure + + align:start position:0% +and that's cool because you can measure + + + align:start position:0% +and that's cool because you can measure +this right you can take a potential you + + align:start position:0% +this right you can take a potential you + + + align:start position:0% +this right you can take a potential you +can literally just send in a beam of + + align:start position:0% +can literally just send in a beam of + + + align:start position:0% +can literally just send in a beam of +particles you can ask how likely are + + align:start position:0% +particles you can ask how likely are + + + align:start position:0% +particles you can ask how likely are +they to get out and more importantly if + + align:start position:0% +they to get out and more importantly if + + + align:start position:0% +they to get out and more importantly if +i build a wave packet + + align:start position:0% +i build a wave packet + + + align:start position:0% +i build a wave packet +on average what's the time delay or + + align:start position:0% +on average what's the time delay or + + + align:start position:0% +on average what's the time delay or +acceleration of the transmitted wave + + align:start position:0% +acceleration of the transmitted wave + + + align:start position:0% +acceleration of the transmitted wave +pack and that way i can measure the + + align:start position:0% +pack and that way i can measure the + + + align:start position:0% +pack and that way i can measure the +phase as well i can measure both the + + align:start position:0% +phase as well i can measure both the + + + align:start position:0% +phase as well i can measure both the +transmission probabilities and the + + align:start position:0% +transmission probabilities and the + + + align:start position:0% +transmission probabilities and the +phases release the gradient to the phase + + align:start position:0% +phases release the gradient to the phase + + + align:start position:0% +phases release the gradient to the phase +with energy hold on + + align:start position:0% +with energy hold on + + + align:start position:0% +with energy hold on +go ahead is there a special condition + + align:start position:0% +go ahead is there a special condition + + + align:start position:0% +go ahead is there a special condition +that we can impose to see the resonance + + align:start position:0% +that we can impose to see the resonance + + + align:start position:0% +that we can impose to see the resonance +excellent question hold on to your + + align:start position:0% +excellent question hold on to your + + + align:start position:0% +excellent question hold on to your +question for a second + + align:start position:0% +question for a second + + + align:start position:0% +question for a second +yeah so there's an enormous amount of + + align:start position:0% +yeah so there's an enormous amount of + + + align:start position:0% +yeah so there's an enormous amount of +the physics of scattering contained in + + align:start position:0% +the physics of scattering contained in + + + align:start position:0% +the physics of scattering contained in +the s matrix and you can measure the s + + align:start position:0% +the s matrix and you can measure the s + + + align:start position:0% +the s matrix and you can measure the s +matrix and you can measure its + + align:start position:0% +matrix and you can measure its + + + align:start position:0% +matrix and you can measure its +dependence on the energy you can measure + + align:start position:0% +dependence on the energy you can measure + + + align:start position:0% +dependence on the energy you can measure +the coefficients s12 and s22 their + + align:start position:0% +the coefficients s12 and s22 their + + + align:start position:0% +the coefficients s12 and s22 their +phases and their amplitudes as a + + align:start position:0% +phases and their amplitudes as a + + + align:start position:0% +phases and their amplitudes as a +function of energy and you can plot them + + align:start position:0% +function of energy and you can plot them + + + align:start position:0% +function of energy and you can plot them +and here's what i want to convince you + + align:start position:0% +and here's what i want to convince you + + + align:start position:0% +and here's what i want to convince you +of + + align:start position:0% +of + + + align:start position:0% +of +if you plot those + + align:start position:0% +if you plot those + + + align:start position:0% +if you plot those +and + + align:start position:0% +and + + + align:start position:0% +and +look at how the functions behave as + + align:start position:0% +look at how the functions behave as + + + align:start position:0% +look at how the functions behave as +functions of energy and ask how do those + + align:start position:0% +functions of energy and ask how do those + + + align:start position:0% +functions of energy and ask how do those +functions extend + + align:start position:0% +functions extend + + + align:start position:0% +functions extend +to negative energy + + align:start position:0% +to negative energy + + + align:start position:0% +to negative energy +by just drawing the line continuing the + + align:start position:0% +by just drawing the line continuing the + + + align:start position:0% +by just drawing the line continuing the +lines + + align:start position:0% +lines + + + align:start position:0% +lines +you can derive the energy of any bound + + align:start position:0% +you can derive the energy of any bound + + + align:start position:0% +you can derive the energy of any bound +states in the system too + + align:start position:0% + + + + align:start position:0% + +knowledge of the scattering + + align:start position:0% +knowledge of the scattering + + + align:start position:0% +knowledge of the scattering +is enough to determine + + align:start position:0% +is enough to determine + + + align:start position:0% +is enough to determine +the bound state energies of a system and + + align:start position:0% +the bound state energies of a system and + + + align:start position:0% +the bound state energies of a system and +let me show you that + + align:start position:0% +let me show you that + + + align:start position:0% +let me show you that +and this is one of the coolest things in + + align:start position:0% +and this is one of the coolest things in + + + align:start position:0% +and this is one of the coolest things in +quantum mechanics so here's how this + + align:start position:0% +quantum mechanics so here's how this + + + align:start position:0% +quantum mechanics so here's how this +works + + align:start position:0% +works + + + align:start position:0% +works +we have from the definition of the s + + align:start position:0% +we have from the definition of the s + + + align:start position:0% +we have from the definition of the s +matrix that bc is equal to the s matrix + + align:start position:0% +matrix that bc is equal to the s matrix + + + align:start position:0% +matrix that bc is equal to the s matrix +on a d + + align:start position:0% +on a d + + + align:start position:0% +on a d +right where the wave function let me + + align:start position:0% +right where the wave function let me + + + align:start position:0% +right where the wave function let me +just put this back in the original form + + align:start position:0% +just put this back in the original form + + + align:start position:0% +just put this back in the original form +is c d + + align:start position:0% +is c d + + + align:start position:0% +is c d +a b + + align:start position:0% +a b + + + align:start position:0% +a b +e to the i k x e to the minus i k x + + align:start position:0% +e to the i k x e to the minus i k x + + + align:start position:0% +e to the i k x e to the minus i k x +and e to the plus i k x e to the minus i + + align:start position:0% +and e to the plus i k x e to the minus i + + + align:start position:0% +and e to the plus i k x e to the minus i +k x yeah so that's the definition of the + + align:start position:0% +k x yeah so that's the definition of the + + + align:start position:0% +k x yeah so that's the definition of the +s matrix the s matrix at a given energy + + align:start position:0% +s matrix the s matrix at a given energy + + + align:start position:0% +s matrix the s matrix at a given energy +e is this relation is a coefficient + + align:start position:0% +e is this relation is a coefficient + + + align:start position:0% +e is this relation is a coefficient +relation matrix between the in-going + + align:start position:0% +relation matrix between the in-going + + + align:start position:0% +relation matrix between the in-going +outgoing or more to the point a and d + + align:start position:0% +outgoing or more to the point a and d + + + align:start position:0% +outgoing or more to the point a and d +and in all of this i've assumed that the + + align:start position:0% +and in all of this i've assumed that the + + + align:start position:0% +and in all of this i've assumed that the +energy was positive that the k1 and k2 + + align:start position:0% +energy was positive that the k1 and k2 + + + align:start position:0% +energy was positive that the k1 and k2 +are are positive and real but now let's + + align:start position:0% +are are positive and real but now let's + + + align:start position:0% +are are positive and real but now let's +ask the question what would have + + align:start position:0% +ask the question what would have + + + align:start position:0% +ask the question what would have +happened if in the whole process i had + + align:start position:0% +happened if in the whole process i had + + + align:start position:0% +happened if in the whole process i had +taken um + + align:start position:0% + + + + align:start position:0% + +take + + align:start position:0% + + + + align:start position:0% + +the energy less than zero so if the + + align:start position:0% +the energy less than zero so if the + + + align:start position:0% +the energy less than zero so if the +energy were less than zero instead of k + + align:start position:0% +energy were less than zero instead of k + + + align:start position:0% +energy were less than zero instead of k +k would be replaced by i alpha let's + + align:start position:0% +k would be replaced by i alpha let's + + + align:start position:0% +k would be replaced by i alpha let's +think about what that does + + align:start position:0% +think about what that does + + + align:start position:0% +think about what that does +if k is i alpha + + align:start position:0% +if k is i alpha + + + align:start position:0% +if k is i alpha +this is e to the i k is minus alpha + + align:start position:0% +this is e to the i k is minus alpha + + + align:start position:0% +this is e to the i k is minus alpha +and minus ik is plus alpha plus alpha + + align:start position:0% +and minus ik is plus alpha plus alpha + + + align:start position:0% +and minus ik is plus alpha plus alpha +similarly i k times i that gives me a + + align:start position:0% +similarly i k times i that gives me a + + + align:start position:0% +similarly i k times i that gives me a +minus alpha + + align:start position:0% +minus alpha + + + align:start position:0% +minus alpha +and this gives me a plus alpha + + align:start position:0% +and this gives me a plus alpha + + + align:start position:0% +and this gives me a plus alpha +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +so as equations they're the same + + align:start position:0% +so as equations they're the same + + + align:start position:0% +so as equations they're the same +equations with k replaced by + + align:start position:0% +equations with k replaced by + + + align:start position:0% +equations with k replaced by +i alpha + + align:start position:0% +i alpha + + + align:start position:0% +i alpha +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +and now what must be true for this state + + align:start position:0% +and now what must be true for this state + + + align:start position:0% +and now what must be true for this state +for these states to be normalizable + + align:start position:0% +for these states to be normalizable + + + align:start position:0% +for these states to be normalizable +what must be true for example of a + + align:start position:0% + + + + align:start position:0% + +a must be zero because at minus infinity + + align:start position:0% +a must be zero because at minus infinity + + + align:start position:0% +a must be zero because at minus infinity +this diverges it's not normalizable + + align:start position:0% +this diverges it's not normalizable + + + align:start position:0% +this diverges it's not normalizable +so in order to be a bouncy in order to + + align:start position:0% +so in order to be a bouncy in order to + + + align:start position:0% +so in order to be a bouncy in order to +have a physical state a must be zero + + align:start position:0% +have a physical state a must be zero + + + align:start position:0% +have a physical state a must be zero +what about d + + align:start position:0% +what about d + + + align:start position:0% +what about d +same reason it's got to be zero at + + align:start position:0% +same reason it's got to be zero at + + + align:start position:0% +same reason it's got to be zero at +positive infinity these guys are + + align:start position:0% +positive infinity these guys are + + + align:start position:0% +positive infinity these guys are +convergent so c and b can be non-zero so + + align:start position:0% +convergent so c and b can be non-zero so + + + align:start position:0% +convergent so c and b can be non-zero so +now here's my question can i scatter a + + align:start position:0% +now here's my question can i scatter a + + + align:start position:0% +now here's my question can i scatter a +state from a b we know that these + + align:start position:0% +state from a b we know that these + + + align:start position:0% +state from a b we know that these +relations must be true because all these + + align:start position:0% +relations must be true because all these + + + align:start position:0% +relations must be true because all these +relations are encoding all these + + align:start position:0% +relations are encoding all these + + + align:start position:0% +relations are encoding all these +relations are encoding is how a solution + + align:start position:0% +relations are encoding is how a solution + + + align:start position:0% +relations are encoding is how a solution +here matches to a solution here through + + align:start position:0% +here matches to a solution here through + + + align:start position:0% +here matches to a solution here through +a potential in between with continuity + + align:start position:0% +a potential in between with continuity + + + align:start position:0% +a potential in between with continuity +continuity of the derivative and + + align:start position:0% +continuity of the derivative and + + + align:start position:0% +continuity of the derivative and +anything else that's true of that + + align:start position:0% +anything else that's true of that + + + align:start position:0% +anything else that's true of that +potential inside all that s is doing + + align:start position:0% +potential inside all that s is doing + + + align:start position:0% +potential inside all that s is doing +from that point of view is telling me + + align:start position:0% +from that point of view is telling me + + + align:start position:0% +from that point of view is telling me +how these coefficients match onto these + + align:start position:0% +how these coefficients match onto these + + + align:start position:0% +how these coefficients match onto these +coefficients yes now what for a bound + + align:start position:0% +coefficients yes now what for a bound + + + align:start position:0% +coefficients yes now what for a bound +state so if we have e less than zero + + align:start position:0% +state so if we have e less than zero + + + align:start position:0% +state so if we have e less than zero +what must be true we must be true that a + + align:start position:0% +what must be true we must be true that a + + + align:start position:0% +what must be true we must be true that a +d is equal to + + align:start position:0% +d is equal to + + + align:start position:0% +d is equal to +zero and in particular zero zero right + + align:start position:0% +zero and in particular zero zero right + + + align:start position:0% +zero and in particular zero zero right +so what are b and c + + align:start position:0% +so what are b and c + + + align:start position:0% +so what are b and c +oh well a matrix times 0 is equal to + + align:start position:0% +oh well a matrix times 0 is equal to + + + align:start position:0% +oh well a matrix times 0 is equal to +unless + + align:start position:0% + + + + align:start position:0% + +unless the matrix itself is diverging + + align:start position:0% +unless the matrix itself is diverging + + + align:start position:0% +unless the matrix itself is diverging +and then you have to be more careful but + + align:start position:0% +and then you have to be more careful but + + + align:start position:0% +and then you have to be more careful but +let's be naive for the moment + + align:start position:0% +let's be naive for the moment + + + align:start position:0% +let's be naive for the moment +if a is 0 0 then in order for b and c to + + align:start position:0% +if a is 0 0 then in order for b and c to + + + align:start position:0% +if a is 0 0 then in order for b and c to +be non-zero + + align:start position:0% + + + + align:start position:0% + +s must have a pole + + align:start position:0% + + + + align:start position:0% + +s must go like one over zero + + align:start position:0% + + + + align:start position:0% + +s must diverge at some special value of + + align:start position:0% +s must diverge at some special value of + + + align:start position:0% +s must diverge at some special value of +the energy + + align:start position:0% +the energy + + + align:start position:0% +the energy +okay well that's easy that tells you + + align:start position:0% +okay well that's easy that tells you + + + align:start position:0% +okay well that's easy that tells you +that if you look at any particular + + align:start position:0% +that if you look at any particular + + + align:start position:0% +that if you look at any particular +coefficient in s + + align:start position:0% +coefficient in s + + + align:start position:0% +coefficient in s +any of the matrix elements of s + + align:start position:0% +any of the matrix elements of s + + + align:start position:0% +any of the matrix elements of s +the numerator can be whatever you want + + align:start position:0% +the numerator can be whatever you want + + + align:start position:0% +the numerator can be whatever you want +some finite number but the denominator + + align:start position:0% +some finite number but the denominator + + + align:start position:0% +some finite number but the denominator +had better be + + align:start position:0% +had better be + + + align:start position:0% +had better be +zero + + align:start position:0% +zero + + + align:start position:0% +zero +so let's look at the denominator + + align:start position:0% +so let's look at the denominator + + + align:start position:0% +so let's look at the denominator +if i compute s21 + + align:start position:0% +if i compute s21 + + + align:start position:0% +if i compute s21 +oh actually let me do this over here + + align:start position:0% +oh actually let me do this over here + + + align:start position:0% +oh actually let me do this over here +let's compute + + align:start position:0% +let's compute + + + align:start position:0% +let's compute +ah no it's all filled damn + + align:start position:0% +ah no it's all filled damn + + + align:start position:0% +ah no it's all filled damn +let's do it over here + + align:start position:0% +let's do it over here + + + align:start position:0% +let's do it over here +so if i look at s21 for the barrier or + + align:start position:0% +so if i look at s21 for the barrier or + + + align:start position:0% +so if i look at s21 for the barrier or +for the potential well scattering off + + align:start position:0% +for the potential well scattering off + + + align:start position:0% +for the potential well scattering off +the potential well that we looked at at + + align:start position:0% +the potential well that we looked at at + + + align:start position:0% +the potential well that we looked at at +the beginning of today's lecture + + align:start position:0% + + + + align:start position:0% + +this guy + + align:start position:0% +this guy + + + align:start position:0% +this guy +and now i'm going to look at + + align:start position:0% +and now i'm going to look at + + + align:start position:0% +and now i'm going to look at +s21 + + align:start position:0% +s21 + + + align:start position:0% +s21 +one of the coefficients of this guys + + align:start position:0% +one of the coefficients of this guys + + + align:start position:0% +one of the coefficients of this guys +also known as the scattering amplitude t + + align:start position:0% +also known as the scattering amplitude t + + + align:start position:0% +also known as the scattering amplitude t +for the well + + align:start position:0% + + + + align:start position:0% + +this is equal to + + align:start position:0% +this is equal to + + + align:start position:0% +this is equal to +and it's got awful expression + + align:start position:0% +and it's got awful expression + + + align:start position:0% +and it's got awful expression +2 k1 k2 + + align:start position:0% +2 k1 k2 + + + align:start position:0% +2 k1 k2 +e to the ik k2 l + + align:start position:0% +e to the ik k2 l + + + align:start position:0% +e to the ik k2 l +over + + align:start position:0% +over + + + align:start position:0% +over + + align:start position:0% + + + align:start position:0% +1 k 2 + + align:start position:0% +1 k 2 + + + align:start position:0% +1 k 2 +cos + + align:start position:0% +cos + + + align:start position:0% +cos +of k prime l + + align:start position:0% +of k prime l + + + align:start position:0% +of k prime l +minus i + + align:start position:0% +minus i + + + align:start position:0% +minus i +k squared plus k 1 squared plus k 2 + + align:start position:0% +k squared plus k 1 squared plus k 2 + + + align:start position:0% +k squared plus k 1 squared plus k 2 +squared + + align:start position:0% +squared + + + align:start position:0% +squared +times sine + + align:start position:0% +times sine + + + align:start position:0% +times sine +of k + + align:start position:0% +of k + + + align:start position:0% +of k +2 l + + align:start position:0% +2 l + + + align:start position:0% +2 l +okay this is some horrible thing but now + + align:start position:0% +okay this is some horrible thing but now + + + align:start position:0% +okay this is some horrible thing but now +i ask the condition look when does this + + align:start position:0% +i ask the condition look when does this + + + align:start position:0% +i ask the condition look when does this +have a pole for what values of the + + align:start position:0% +have a pole for what values of the + + + align:start position:0% +have a pole for what values of the +energy does this when the energy is + + align:start position:0% +energy does this when the energy is + + + align:start position:0% +energy does this when the energy is +continued to be negative + + align:start position:0% +continued to be negative + + + align:start position:0% +continued to be negative +for what values does this have a pole or + + align:start position:0% +for what values does this have a pole or + + + align:start position:0% +for what values does this have a pole or +does the denominator have a zero and the + + align:start position:0% +does the denominator have a zero and the + + + align:start position:0% +does the denominator have a zero and the +answer is if you take this and you + + align:start position:0% +answer is if you take this and you + + + align:start position:0% +answer is if you take this and you +massage the equation this is equal to 0 + + align:start position:0% +massage the equation this is equal to 0 + + + align:start position:0% +massage the equation this is equal to 0 +a little bit you get the following + + align:start position:0% +a little bit you get the following + + + align:start position:0% +a little bit you get the following +expression + + align:start position:0% +expression + + + align:start position:0% +expression +k2 l upon 2 + + align:start position:0% +k2 l upon 2 + + + align:start position:0% +k2 l upon 2 +tangent + + align:start position:0% +tangent + + + align:start position:0% +tangent +of k2 l + + align:start position:0% +of k2 l + + + align:start position:0% +of k2 l +upon 2 is equal to k1 l upon 2. this is + + align:start position:0% +upon 2 is equal to k1 l upon 2. this is + + + align:start position:0% +upon 2 is equal to k1 l upon 2. this is +the condition for the bound state + + align:start position:0% +the condition for the bound state + + + align:start position:0% +the condition for the bound state +energies of the square well and we've + + align:start position:0% +energies of the square well and we've + + + align:start position:0% +energies of the square well and we've +computed it using knowledge only of the + + align:start position:0% +computed it using knowledge only of the + + + align:start position:0% +computed it using knowledge only of the +scattering states if you took particles + + align:start position:0% +scattering states if you took particles + + + align:start position:0% +scattering states if you took particles +and a square well and roll the particles + + align:start position:0% +and a square well and roll the particles + + + align:start position:0% +and a square well and roll the particles +across the square well potential and + + align:start position:0% +across the square well potential and + + + align:start position:0% +across the square well potential and +measured as a function of energy + + align:start position:0% +measured as a function of energy + + + align:start position:0% +measured as a function of energy +the scattering amplitude the + + align:start position:0% +the scattering amplitude the + + + align:start position:0% +the scattering amplitude the +transmission amplitude in particular s21 + + align:start position:0% +transmission amplitude in particular s21 + + + align:start position:0% +transmission amplitude in particular s21 +an element to the s matrix and you + + align:start position:0% +an element to the s matrix and you + + + align:start position:0% +an element to the s matrix and you +plotted it as a function of energy and + + align:start position:0% +plotted it as a function of energy and + + + align:start position:0% +plotted it as a function of energy and +then you approximated that by + + align:start position:0% +then you approximated that by + + + align:start position:0% +then you approximated that by +a function of energy that satisfies the + + align:start position:0% +a function of energy that satisfies the + + + align:start position:0% +a function of energy that satisfies the +basic properties of unitarity + + align:start position:0% +basic properties of unitarity + + + align:start position:0% +basic properties of unitarity +what you would find is that when you + + align:start position:0% +what you would find is that when you + + + align:start position:0% +what you would find is that when you +then extend that function in mathematica + + align:start position:0% +then extend that function in mathematica + + + align:start position:0% +then extend that function in mathematica +to minus a particular value of the + + align:start position:0% +to minus a particular value of the + + + align:start position:0% +to minus a particular value of the +energy the denominator diverges at that + + align:start position:0% +energy the denominator diverges at that + + + align:start position:0% +energy the denominator diverges at that +energy + + align:start position:0% +energy + + + align:start position:0% +energy +you know that there will be a bound + + align:start position:0% +you know that there will be a bound + + + align:start position:0% +you know that there will be a bound +state + + align:start position:0% +state + + + align:start position:0% +state +and so from scattering you've determined + + align:start position:0% +and so from scattering you've determined + + + align:start position:0% +and so from scattering you've determined +the existence of a bound state and this + + align:start position:0% +the existence of a bound state and this + + + align:start position:0% +the existence of a bound state and this +is how we find an awful lot of the + + align:start position:0% +is how we find an awful lot of the + + + align:start position:0% +is how we find an awful lot of the +particles that we actually deduce must + + align:start position:0% +particles that we actually deduce must + + + align:start position:0% +particles that we actually deduce must +exist in the real world + + align:start position:0% +exist in the real world + + + align:start position:0% +exist in the real world +we'll pick up next time + + align:start position:0% +we'll pick up next time + + + align:start position:0% +we'll pick up next time +[Applause] \ No newline at end of file diff --git a/xqmEuE97KzI.txt b/xqmEuE97KzI.txt new file mode 100644 index 0000000000000000000000000000000000000000..c8dc72c28c45574bdf43fdae86062473a97526fa --- /dev/null +++ b/xqmEuE97KzI.txt @@ -0,0 +1,483 @@ +align:start position:0% + +you have another sheet of paper + + align:start position:0% + + + + align:start position:0% + +now we want to be able to communicate + + align:start position:0% +now we want to be able to communicate + + + align:start position:0% +now we want to be able to communicate +with the local people + + align:start position:0% +with the local people + + + align:start position:0% +with the local people +and ask for directions + + align:start position:0% +and ask for directions + + + align:start position:0% +and ask for directions +so you see that there are numbers close + + align:start position:0% +so you see that there are numbers close + + + align:start position:0% +so you see that there are numbers close +to each sentence okay so you should + + align:start position:0% +to each sentence okay so you should + + + align:start position:0% +to each sentence okay so you should +choose the number + + align:start position:0% +choose the number + + + align:start position:0% +choose the number +so try zero + + align:start position:0% +so try zero + + + align:start position:0% +so try zero +Mario Uno Anita + + align:start position:0% + + + + align:start position:0% + +so Circle your number so that you know + + align:start position:0% +so Circle your number so that you know + + + align:start position:0% +so Circle your number so that you know +when it's your turn so we first read it + + align:start position:0% +when it's your turn so we first read it + + + align:start position:0% +when it's your turn so we first read it +and then we try to understand and follow + + align:start position:0% +and then we try to understand and follow + + + align:start position:0% +and then we try to understand and follow +la cartina + + align:start position:0% + + + + align:start position:0% + +okay here zero + + align:start position:0% +okay here zero + + + align:start position:0% +okay here zero +Uno + + align:start position:0% +Uno + + + align:start position:0% +Uno +Gomez + + align:start position:0% + + + + align:start position:0% + +let's see what we're saying here we are + + align:start position:0% +let's see what we're saying here we are + + + align:start position:0% +let's see what we're saying here we are +having a formal conversation so we are + + align:start position:0% +having a formal conversation so we are + + + align:start position:0% +having a formal conversation so we are +using always the third person singular + + align:start position:0% +using always the third person singular + + + align:start position:0% +using always the third person singular +we're saying + + align:start position:0% +we're saying + + + align:start position:0% +we're saying +instead of scuza and we're saying + + align:start position:0% +instead of scuza and we're saying + + + align:start position:0% +instead of scuza and we're saying +instead of poi that we were using it for + + align:start position:0% +instead of poi that we were using it for + + + align:start position:0% +instead of poi that we were using it for +so first sentence is Miss Koozie + + align:start position:0% + + + + align:start position:0% + +what does it means + + align:start position:0% + + + + align:start position:0% + +excuse me + + align:start position:0% + + + + align:start position:0% + +foreign + + align:start position:0% + + + + align:start position:0% + +foreign + + align:start position:0% + + + + align:start position:0% + +try again + + align:start position:0% + + + + align:start position:0% + +I wanna hear your voice + + align:start position:0% + + + + align:start position:0% + +and now you should look at the map + + align:start position:0% + + + + align:start position:0% + +yeah + + align:start position:0% + + + + align:start position:0% + +but where the train station is + + align:start position:0% +but where the train station is + + + align:start position:0% +but where the train station is +so he says + + align:start position:0% + + + + align:start position:0% + +so what does it means + + align:start position:0% + + + + align:start position:0% + +that is left + + align:start position:0% +that is left + + + align:start position:0% +that is left +foreign + + align:start position:0% + + + + align:start position:0% + +so what are we doing now + + align:start position:0% +so what are we doing now + + + align:start position:0% +so what are we doing now +yes we're making a rice + + align:start position:0% + + + + align:start position:0% + +that means + + align:start position:0% + + + + align:start position:0% + +40. + + align:start position:0% + + + + align:start position:0% + +foreign + + align:start position:0% + + + + align:start position:0% + +intersections + + align:start position:0% + + + + align:start position:0% + +we should say + + align:start position:0% + + + + align:start position:0% + +a small thing in crochet + + align:start position:0% +a small thing in crochet + + + align:start position:0% +a small thing in crochet +okay so we have to pass many craft + + align:start position:0% +okay so we have to pass many craft + + + align:start position:0% +okay so we have to pass many craft +things and that's the jiri at sinistra + + align:start position:0% +things and that's the jiri at sinistra + + + align:start position:0% +things and that's the jiri at sinistra +so which one is + + align:start position:0% +so which one is + + + align:start position:0% +so which one is +to the left so we turn left + + align:start position:0% + + + + align:start position:0% + +they're saying dogs + + align:start position:0% + + + + align:start position:0% + +to the left + + align:start position:0% + + + + align:start position:0% + +is very long and I couldn't take notes + + align:start position:0% +is very long and I couldn't take notes + + + align:start position:0% +is very long and I couldn't take notes +so that kind of fell asleep so + + align:start position:0% +so that kind of fell asleep so + + + align:start position:0% +so that kind of fell asleep so +I may ask + + align:start position:0% + + + + align:start position:0% + +yes + + align:start position:0% +yes + + + align:start position:0% +yes +because I'm talking about La Fontana + + align:start position:0% +because I'm talking about La Fontana + + + align:start position:0% +because I'm talking about La Fontana +which is + + align:start position:0% + + + + align:start position:0% + +because otherwise you're saying it's not + + align:start position:0% +because otherwise you're saying it's not + + + align:start position:0% +because otherwise you're saying it's not +funny + + align:start position:0% + + + + align:start position:0% + +to run + + align:start position:0% + + + + align:start position:0% + +there is a song + + align:start position:0% + + + + align:start position:0% + +thank you \ No newline at end of file diff --git a/xvUz7P-DjhI.txt b/xvUz7P-DjhI.txt new file mode 100644 index 0000000000000000000000000000000000000000..31b9c4bc1d070a92b27b38d492b8661cd1e3645a --- /dev/null +++ b/xvUz7P-DjhI.txt @@ -0,0 +1,10477 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a creative commons license + + align:start position:0% +a creative commons license + + + align:start position:0% +a creative commons license +your support will help mit + + align:start position:0% +your support will help mit + + + align:start position:0% +your support will help mit +opencourseware continue to offer high + + align:start position:0% +opencourseware continue to offer high + + + align:start position:0% +opencourseware continue to offer high +quality educational resources for free + + align:start position:0% +quality educational resources for free + + + align:start position:0% +quality educational resources for free +to make a donation or view additional + + align:start position:0% +to make a donation or view additional + + + align:start position:0% +to make a donation or view additional +materials from hundreds of mit courses + + align:start position:0% +materials from hundreds of mit courses + + + align:start position:0% +materials from hundreds of mit courses +visit mit open courseware at ocw.mit.edu + + align:start position:0% + + + + align:start position:0% + +so we're going to be talking about + + align:start position:0% +so we're going to be talking about + + + align:start position:0% +so we're going to be talking about +normal modes + + align:start position:0% + + + + align:start position:0% + +and you've already done a normal mode + + align:start position:0% +and you've already done a normal mode + + + align:start position:0% +and you've already done a normal mode +calculation on trans assist acetylene so + + align:start position:0% +calculation on trans assist acetylene so + + + align:start position:0% +calculation on trans assist acetylene so +you know most of this stuff + + align:start position:0% +you know most of this stuff + + + align:start position:0% +you know most of this stuff +but the notes contain + + align:start position:0% +but the notes contain + + + align:start position:0% +but the notes contain +a lot of + + align:start position:0% +a lot of + + + align:start position:0% +a lot of +uh + + align:start position:0% +uh + + + align:start position:0% +uh +stuff worked out completely on water + + align:start position:0% +stuff worked out completely on water + + + align:start position:0% +stuff worked out completely on water +which is simpler than the case you did + + align:start position:0% +which is simpler than the case you did + + + align:start position:0% +which is simpler than the case you did +but it's also there's more here than + + align:start position:0% +but it's also there's more here than + + + align:start position:0% +but it's also there's more here than +what you did + + align:start position:0% +what you did + + + align:start position:0% +what you did +and + + align:start position:0% + + + + align:start position:0% + +we will + + align:start position:0% +we will + + + align:start position:0% +we will +deal with the vibrational normal modes + + align:start position:0% +deal with the vibrational normal modes + + + align:start position:0% +deal with the vibrational normal modes +of water and then make some comments + + align:start position:0% +of water and then make some comments + + + align:start position:0% +of water and then make some comments +about why are certain internal + + align:start position:0% +about why are certain internal + + + align:start position:0% +about why are certain internal +coordinates mixed and others not + + align:start position:0% +coordinates mixed and others not + + + align:start position:0% +coordinates mixed and others not +and that brings up the concept of + + align:start position:0% +and that brings up the concept of + + + align:start position:0% +and that brings up the concept of +symmetry making symmetrized normal modes + + align:start position:0% +symmetry making symmetrized normal modes + + + align:start position:0% +symmetry making symmetrized normal modes +which block diagonalizes both f and g + + align:start position:0% +which block diagonalizes both f and g + + + align:start position:0% +which block diagonalizes both f and g +matrices + + align:start position:0% +matrices + + + align:start position:0% +matrices +and + + align:start position:0% + + + + align:start position:0% + +then a more general or + + align:start position:0% + + + + align:start position:0% + +discussion once you have symmetrized you + + align:start position:0% +discussion once you have symmetrized you + + + align:start position:0% +discussion once you have symmetrized you +might have a mixture you have might have + + align:start position:0% +might have a mixture you have might have + + + align:start position:0% +might have a mixture you have might have +states of the same symmetry species + + align:start position:0% +states of the same symmetry species + + + align:start position:0% +states of the same symmetry species +abandon a stretch + + align:start position:0% +abandon a stretch + + + align:start position:0% +abandon a stretch +and what makes them mix or not + + align:start position:0% +and what makes them mix or not + + + align:start position:0% +and what makes them mix or not +and so so some discussion of how do you + + align:start position:0% +and so so some discussion of how do you + + + align:start position:0% +and so so some discussion of how do you +read these matrices + + align:start position:0% +read these matrices + + + align:start position:0% +read these matrices +and infer causality for + + align:start position:0% +and infer causality for + + + align:start position:0% +and infer causality for +mixing of different kinds of internal + + align:start position:0% +mixing of different kinds of internal + + + align:start position:0% +mixing of different kinds of internal +motions so + + align:start position:0% +motions so + + + align:start position:0% +motions so +uh + + align:start position:0% + + + + align:start position:0% + +read f + + align:start position:0% +read f + + + align:start position:0% +read f +and g matrices + + align:start position:0% +and g matrices + + + align:start position:0% +and g matrices +and there'll be some discussion of + + align:start position:0% +and there'll be some discussion of + + + align:start position:0% +and there'll be some discussion of +kinetic energy coupling and potential + + align:start position:0% +kinetic energy coupling and potential + + + align:start position:0% +kinetic energy coupling and potential +energy coupling + + align:start position:0% +energy coupling + + + align:start position:0% +energy coupling +and then + + align:start position:0% + + + + align:start position:0% + +a refuge for + + align:start position:0% +a refuge for + + + align:start position:0% +a refuge for +the ill-prepared i go to something that + + align:start position:0% +the ill-prepared i go to something that + + + align:start position:0% +the ill-prepared i go to something that +i know very well uh pollyanne so if we + + align:start position:0% +i know very well uh pollyanne so if we + + + align:start position:0% +i know very well uh pollyanne so if we +get through all of the notes we'll end + + align:start position:0% +get through all of the notes we'll end + + + align:start position:0% +get through all of the notes we'll end +with with + + align:start position:0% +with with + + + align:start position:0% +with with +uh a description of + + align:start position:0% +uh a description of + + + align:start position:0% +uh a description of +the coupling among many systematically + + align:start position:0% +the coupling among many systematically + + + align:start position:0% +the coupling among many systematically +near degenerate levels + + align:start position:0% +near degenerate levels + + + align:start position:0% +near degenerate levels +and that's the menu + + align:start position:0% +and that's the menu + + + align:start position:0% +and that's the menu +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so + + align:start position:0% +so + + + align:start position:0% +so +we have + + align:start position:0% +we have + + + align:start position:0% +we have +a whole bunch of + + align:start position:0% +a whole bunch of + + + align:start position:0% +a whole bunch of +transformations we start out with + + align:start position:0% +transformations we start out with + + + align:start position:0% +transformations we start out with +cartesian displacements we do mass + + align:start position:0% +cartesian displacements we do mass + + + align:start position:0% +cartesian displacements we do mass +weighted cartesians then we go to + + align:start position:0% +weighted cartesians then we go to + + + align:start position:0% +weighted cartesians then we go to +internal coordinates + + align:start position:0% +internal coordinates + + + align:start position:0% +internal coordinates +and then we uh get to the normal + + align:start position:0% +and then we uh get to the normal + + + align:start position:0% +and then we uh get to the normal +coordinates and we have some + + align:start position:0% +coordinates and we have some + + + align:start position:0% +coordinates and we have some +equations like this + + align:start position:0% +equations like this + + + align:start position:0% +equations like this +this relates + + align:start position:0% +this relates + + + align:start position:0% +this relates +the internal displacements to the normal + + align:start position:0% +the internal displacements to the normal + + + align:start position:0% +the internal displacements to the normal +displacements this is + + align:start position:0% +displacements this is + + + align:start position:0% +displacements this is +this looks like quantum mechanics but + + align:start position:0% +this looks like quantum mechanics but + + + align:start position:0% +this looks like quantum mechanics but +it's just a + + align:start position:0% +it's just a + + + align:start position:0% +it's just a +form of + + align:start position:0% +form of + + + align:start position:0% +form of +a shorthand + + align:start position:0% +a shorthand + + + align:start position:0% +a shorthand +and it says okay + + align:start position:0% +and it says okay + + + align:start position:0% +and it says okay +the jth + + align:start position:0% +the jth + + + align:start position:0% +the jth +normal + + align:start position:0% +normal + + + align:start position:0% +normal +displacement is given by the rules of + + align:start position:0% +displacement is given by the rules of + + + align:start position:0% +displacement is given by the rules of +matrix multiplication so we would have a + + align:start position:0% +matrix multiplication so we would have a + + + align:start position:0% +matrix multiplication so we would have a +sum over i + + align:start position:0% +sum over i + + + align:start position:0% +sum over i +of l minus 1 i j s + + align:start position:0% +of l minus 1 i j s + + + align:start position:0% +of l minus 1 i j s +j + + align:start position:0% +j + + + align:start position:0% +j +except that i did it wrong + + align:start position:0% + + + + align:start position:0% + +no i did it + + align:start position:0% +no i did it + + + align:start position:0% +no i did it +um + + align:start position:0% +um + + + align:start position:0% +um +well + + align:start position:0% +well + + + align:start position:0% +well +s sub i j i + + align:start position:0% +s sub i j i + + + align:start position:0% +s sub i j i +that good that's good okay + + align:start position:0% +that good that's good okay + + + align:start position:0% +that good that's good okay +um this is the rules for + + align:start position:0% +um this is the rules for + + + align:start position:0% +um this is the rules for +who's beeping + + align:start position:0% +who's beeping + + + align:start position:0% +who's beeping +outside + + align:start position:0% +outside + + + align:start position:0% +outside +okay all right so this is the rules for + + align:start position:0% +okay all right so this is the rules for + + + align:start position:0% +okay all right so this is the rules for +matrix multiplication and this is + + align:start position:0% +matrix multiplication and this is + + + align:start position:0% +matrix multiplication and this is +telling us that if we had this l inverse + + align:start position:0% +telling us that if we had this l inverse + + + align:start position:0% +telling us that if we had this l inverse +matrix + + align:start position:0% +matrix + + + align:start position:0% +matrix +what would we do well we would take the + + align:start position:0% +what would we do well we would take the + + + align:start position:0% +what would we do well we would take the +jth row + + align:start position:0% +jth row + + + align:start position:0% +jth row +of the l inverse matrix and that would + + align:start position:0% +of the l inverse matrix and that would + + + align:start position:0% +of the l inverse matrix and that would +give us the information that we need to + + align:start position:0% +give us the information that we need to + + + align:start position:0% +give us the information that we need to +construct + + align:start position:0% +construct + + + align:start position:0% +construct +the jth + + align:start position:0% +the jth + + + align:start position:0% +the jth +normal mode from all of the internal + + align:start position:0% +normal mode from all of the internal + + + align:start position:0% +normal mode from all of the internal +displacements and i've always i'm always + + align:start position:0% +displacements and i've always i'm always + + + align:start position:0% +displacements and i've always i'm always +troubled or confused about do we want + + align:start position:0% +troubled or confused about do we want + + + align:start position:0% +troubled or confused about do we want +the the row or the column + + align:start position:0% +the the row or the column + + + align:start position:0% +the the row or the column +do we want the inverse matrix or the + + align:start position:0% +do we want the inverse matrix or the + + + align:start position:0% +do we want the inverse matrix or the +non-inverse matrix + + align:start position:0% +non-inverse matrix + + + align:start position:0% +non-inverse matrix +and there's only one correct answer + + align:start position:0% +and there's only one correct answer + + + align:start position:0% +and there's only one correct answer +and this is it + + align:start position:0% +and this is it + + + align:start position:0% +and this is it +okay + + align:start position:0% + + + + align:start position:0% + +we describe + + align:start position:0% +we describe + + + align:start position:0% +we describe +the + + align:start position:0% +the + + + align:start position:0% +the +internal displacements using these + + align:start position:0% +internal displacements using these + + + align:start position:0% +internal displacements using these +st alpha + + align:start position:0% +st alpha + + + align:start position:0% +st alpha +u + + align:start position:0% +u + + + align:start position:0% +u +matrices + + align:start position:0% +matrices + + + align:start position:0% +matrices +displacement vectors alpha refers to the + + align:start position:0% +displacement vectors alpha refers to the + + + align:start position:0% +displacement vectors alpha refers to the +atom t refers to a particular internal + + align:start position:0% +atom t refers to a particular internal + + + align:start position:0% +atom t refers to a particular internal +displacement + + align:start position:0% +displacement + + + align:start position:0% +displacement +and these things are vectors + + align:start position:0% +and these things are vectors + + + align:start position:0% +and these things are vectors +of length one + + align:start position:0% +of length one + + + align:start position:0% +of length one +pointing in the direction where a + + align:start position:0% +pointing in the direction where a + + + align:start position:0% +pointing in the direction where a +displacement of one causes the maximum + + align:start position:0% +displacement of one causes the maximum + + + align:start position:0% +displacement of one causes the maximum +increase in the specified internal + + align:start position:0% +increase in the specified internal + + + align:start position:0% +increase in the specified internal +coordinate + + align:start position:0% +coordinate + + + align:start position:0% +coordinate +and + + align:start position:0% +and + + + align:start position:0% +and +a normal normal + + align:start position:0% + + + + align:start position:0% + +a normal mode would involve harmonic + + align:start position:0% +a normal mode would involve harmonic + + + align:start position:0% +a normal mode would involve harmonic +motion of all of the atoms at the same + + align:start position:0% +motion of all of the atoms at the same + + + align:start position:0% +motion of all of the atoms at the same +frequency + + align:start position:0% +frequency + + + align:start position:0% +frequency +and + + align:start position:0% +and + + + align:start position:0% +and +okay so + + align:start position:0% +okay so + + + align:start position:0% +okay so +that's the review which you + + align:start position:0% +that's the review which you + + + align:start position:0% +that's the review which you +the stuff you know + + align:start position:0% +the stuff you know + + + align:start position:0% +the stuff you know +and + + align:start position:0% +and + + + align:start position:0% +and +now + + align:start position:0% +now + + + align:start position:0% +now +let's talk about water so we have a + + align:start position:0% +let's talk about water so we have a + + + align:start position:0% +let's talk about water so we have a +structure of water uh + + align:start position:0% +structure of water uh + + + align:start position:0% +structure of water uh +we'll call this one there's two this is + + align:start position:0% +we'll call this one there's two this is + + + align:start position:0% +we'll call this one there's two this is +and three this is conventional + + align:start position:0% +and three this is conventional + + + align:start position:0% +and three this is conventional +uh you would think one two three but + + align:start position:0% +uh you would think one two three but + + + align:start position:0% +uh you would think one two three but +this is the way it's most often labeled + + align:start position:0% +this is the way it's most often labeled + + + align:start position:0% +this is the way it's most often labeled +we have an angle and we have two + + align:start position:0% +we have an angle and we have two + + + align:start position:0% +we have an angle and we have two +bond lengths + + align:start position:0% + + + + align:start position:0% + +okay and what we want to do is describe + + align:start position:0% +okay and what we want to do is describe + + + align:start position:0% +okay and what we want to do is describe +all of the internal displacement + + align:start position:0% +all of the internal displacement + + + align:start position:0% +all of the internal displacement +coordinates + + align:start position:0% +coordinates + + + align:start position:0% +coordinates +and + + align:start position:0% +and + + + align:start position:0% +and +build up the f and g matrices with which + + align:start position:0% +build up the f and g matrices with which + + + align:start position:0% +build up the f and g matrices with which +we can solve for all of the problems so + + align:start position:0% +we can solve for all of the problems so + + + align:start position:0% +we can solve for all of the problems so +by uh + + align:start position:0% +by uh + + + align:start position:0% +by uh +we we can we know that there are + + align:start position:0% +we we can we know that there are + + + align:start position:0% +we we can we know that there are +uh three n minus six or three + + align:start position:0% +uh three n minus six or three + + + align:start position:0% +uh three n minus six or three +normal modes there'll be three linearly + + align:start position:0% +normal modes there'll be three linearly + + + align:start position:0% +normal modes there'll be three linearly +independent + + align:start position:0% +independent + + + align:start position:0% +independent +internal displacements + + align:start position:0% +internal displacements + + + align:start position:0% +internal displacements +these three + + align:start position:0% +these three + + + align:start position:0% +these three +are + + align:start position:0% +are + + + align:start position:0% +are +a linearly independent set + + align:start position:0% +a linearly independent set + + + align:start position:0% +a linearly independent set +we can call one of them + + align:start position:0% +we can call one of them + + + align:start position:0% +we can call one of them +and + + align:start position:0% +and + + + align:start position:0% +and +there's no reason to worry about the + + align:start position:0% +there's no reason to worry about the + + + align:start position:0% +there's no reason to worry about the +numbering of the internal displacements + + align:start position:0% +numbering of the internal displacements + + + align:start position:0% +numbering of the internal displacements +but there is a reason to worry about the + + align:start position:0% +but there is a reason to worry about the + + + align:start position:0% +but there is a reason to worry about the +numbering of the normal modes + + align:start position:0% +numbering of the normal modes + + + align:start position:0% +numbering of the normal modes +and so we can choose whatever or we can + + align:start position:0% +and so we can choose whatever or we can + + + align:start position:0% +and so we can choose whatever or we can +call this uh we can call + + align:start position:0% +call this uh we can call + + + align:start position:0% +call this uh we can call +the stretch of + + align:start position:0% +the stretch of + + + align:start position:0% +the stretch of +the three one bond s1 the stretch + + align:start position:0% +the three one bond s1 the stretch + + + align:start position:0% +the three one bond s1 the stretch +of the + + align:start position:0% +of the + + + align:start position:0% +of the +three two bond s2 and the bend + + align:start position:0% + + + + align:start position:0% + +s3 + + align:start position:0% +s3 + + + align:start position:0% +s3 +and we then do the problem okay so + + align:start position:0% + + + + align:start position:0% + +in order to express these internal + + align:start position:0% +in order to express these internal + + + align:start position:0% +in order to express these internal +displacements which are motions of two + + align:start position:0% +displacements which are motions of two + + + align:start position:0% +displacements which are motions of two +or three atoms + + align:start position:0% +or three atoms + + + align:start position:0% +or three atoms +subject to the constraints that we don't + + align:start position:0% +subject to the constraints that we don't + + + align:start position:0% +subject to the constraints that we don't +want to move + + align:start position:0% +want to move + + + align:start position:0% +want to move +the molecule + + align:start position:0% +the molecule + + + align:start position:0% +the molecule +and we don't want to cause rotation + + align:start position:0% +and we don't want to cause rotation + + + align:start position:0% +and we don't want to cause rotation +we go through some + + align:start position:0% +we go through some + + + align:start position:0% +we go through some +vector analysis and we get the + + align:start position:0% +vector analysis and we get the + + + align:start position:0% +vector analysis and we get the +expressions + + align:start position:0% +expressions + + + align:start position:0% +expressions +for the + + align:start position:0% +for the + + + align:start position:0% +for the +little st alphas for the three atoms and + + align:start position:0% +little st alphas for the three atoms and + + + align:start position:0% +little st alphas for the three atoms and +the three internal displacements and + + align:start position:0% +the three internal displacements and + + + align:start position:0% +the three internal displacements and +that's + + align:start position:0% +that's + + + align:start position:0% +that's +a beautiful bit of vector analysis which + + align:start position:0% +a beautiful bit of vector analysis which + + + align:start position:0% +a beautiful bit of vector analysis which +i will not do + + align:start position:0% +i will not do + + + align:start position:0% +i will not do +and it's in the notes + + align:start position:0% +and it's in the notes + + + align:start position:0% +and it's in the notes +and the important thing + + align:start position:0% +and the important thing + + + align:start position:0% +and the important thing +is that + + align:start position:0% +is that + + + align:start position:0% +is that +you take this example + + align:start position:0% +you take this example + + + align:start position:0% +you take this example +and you apply it to a problem + + align:start position:0% +and you apply it to a problem + + + align:start position:0% +and you apply it to a problem +which is not too complicated and you get + + align:start position:0% +which is not too complicated and you get + + + align:start position:0% +which is not too complicated and you get +this you know you get the same results + + align:start position:0% +this you know you get the same results + + + align:start position:0% +this you know you get the same results +so i mean i ideally you'd apply it to + + align:start position:0% +so i mean i ideally you'd apply it to + + + align:start position:0% +so i mean i ideally you'd apply it to +water or d2o + + align:start position:0% +water or d2o + + + align:start position:0% +water or d2o +and see if you get + + align:start position:0% +and see if you get + + + align:start position:0% +and see if you get +if all the analysis is correct now one + + align:start position:0% +if all the analysis is correct now one + + + align:start position:0% +if all the analysis is correct now one +of the things about these guys + + align:start position:0% +of the things about these guys + + + align:start position:0% +of the things about these guys +is there are no + + align:start position:0% +is there are no + + + align:start position:0% +is there are no +masses involved + + align:start position:0% + + + + align:start position:0% + +and that's always bothered me because + + align:start position:0% +and that's always bothered me because + + + align:start position:0% +and that's always bothered me because +you would think that you'd describe the + + align:start position:0% +you would think that you'd describe the + + + align:start position:0% +you would think that you'd describe the +internal displacements in a way where + + align:start position:0% +internal displacements in a way where + + + align:start position:0% +internal displacements in a way where +you don't move the center mass + + align:start position:0% +you don't move the center mass + + + align:start position:0% +you don't move the center mass +but that's not it you're not you're + + align:start position:0% +but that's not it you're not you're + + + align:start position:0% +but that's not it you're not you're +you're + + align:start position:0% +you're + + + align:start position:0% +you're +uh you're moving the two atoms + + align:start position:0% +uh you're moving the two atoms + + + align:start position:0% +uh you're moving the two atoms +equal and opposite amounts + + align:start position:0% +equal and opposite amounts + + + align:start position:0% +equal and opposite amounts +uh in a bond stretch + + align:start position:0% + + + + align:start position:0% + +that's wonderful + + align:start position:0% +that's wonderful + + + align:start position:0% +that's wonderful +yes they are so that takes care of that + + align:start position:0% +yes they are so that takes care of that + + + align:start position:0% +yes they are so that takes care of that +completely fantastic + + align:start position:0% +completely fantastic + + + align:start position:0% +completely fantastic +i didn't understand that thank you + + align:start position:0% +i didn't understand that thank you + + + align:start position:0% +i didn't understand that thank you +i mean it really it's always bothered me + + align:start position:0% +i mean it really it's always bothered me + + + align:start position:0% +i mean it really it's always bothered me +i every time i go through this i see no + + align:start position:0% +i every time i go through this i see no + + + align:start position:0% +i every time i go through this i see no +masses + + align:start position:0% +masses + + + align:start position:0% +masses +they're already in there + + align:start position:0% +they're already in there + + + align:start position:0% +they're already in there +okay + + align:start position:0% +okay + + + align:start position:0% +okay +see + + align:start position:0% +see + + + align:start position:0% +see +we we all learn here + + align:start position:0% +we we all learn here + + + align:start position:0% +we we all learn here +okay so + + align:start position:0% +okay so + + + align:start position:0% +okay so +we derive these uh + + align:start position:0% +we derive these uh + + + align:start position:0% +we derive these uh +little + + align:start position:0% +little + + + align:start position:0% +little +s vectors + + align:start position:0% +s vectors + + + align:start position:0% +s vectors +and we can build up each of the internal + + align:start position:0% +and we can build up each of the internal + + + align:start position:0% +and we can build up each of the internal +displacements + + align:start position:0% +displacements + + + align:start position:0% +displacements +subject to the constraints + + align:start position:0% +subject to the constraints + + + align:start position:0% +subject to the constraints +now one of the things you find is that + + align:start position:0% +now one of the things you find is that + + + align:start position:0% +now one of the things you find is that +here we have two stretches and these + + align:start position:0% +here we have two stretches and these + + + align:start position:0% +here we have two stretches and these +have units of length and here we have a + + align:start position:0% +have units of length and here we have a + + + align:start position:0% +have units of length and here we have a +bend which has a unit of angle and these + + align:start position:0% +bend which has a unit of angle and these + + + align:start position:0% +bend which has a unit of angle and these +don't have the same dimensionality + + align:start position:0% +don't have the same dimensionality + + + align:start position:0% +don't have the same dimensionality +and + + align:start position:0% +and + + + align:start position:0% +and +if you don't like that you can define + + align:start position:0% +if you don't like that you can define + + + align:start position:0% +if you don't like that you can define +a different + + align:start position:0% + + + + align:start position:0% + +bend + + align:start position:0% +bend + + + align:start position:0% +bend +internal displacement simply by + + align:start position:0% +internal displacement simply by + + + align:start position:0% +internal displacement simply by +weighting the change in angle by + + align:start position:0% + + + + align:start position:0% + +the equilibrium bond lengths of the two + + align:start position:0% +the equilibrium bond lengths of the two + + + align:start position:0% +the equilibrium bond lengths of the two +uh + + align:start position:0% +uh + + + align:start position:0% +uh +bonds + + align:start position:0% +bonds + + + align:start position:0% +bonds +and then all of the internal + + align:start position:0% +and then all of the internal + + + align:start position:0% +and then all of the internal +displacements have the same + + align:start position:0% +displacements have the same + + + align:start position:0% +displacements have the same +dimensionality this actually makes you + + align:start position:0% +dimensionality this actually makes you + + + align:start position:0% +dimensionality this actually makes you +feel better because the matrices we're + + align:start position:0% +feel better because the matrices we're + + + align:start position:0% +feel better because the matrices we're +going to develop the f and g matrices + + align:start position:0% +going to develop the f and g matrices + + + align:start position:0% +going to develop the f and g matrices +they also have elements that have + + align:start position:0% +they also have elements that have + + + align:start position:0% +they also have elements that have +different dimensionality + + align:start position:0% +different dimensionality + + + align:start position:0% +different dimensionality +and + + align:start position:0% +and + + + align:start position:0% +and +so + + align:start position:0% +so + + + align:start position:0% +so +that goes away if you make all the + + align:start position:0% +that goes away if you make all the + + + align:start position:0% +that goes away if you make all the +internal displacements have the same + + align:start position:0% +internal displacements have the same + + + align:start position:0% +internal displacements have the same +dimensionality however + + align:start position:0% +dimensionality however + + + align:start position:0% +dimensionality however +even though + + align:start position:0% +even though + + + align:start position:0% +even though +these matrices have elements with + + align:start position:0% +these matrices have elements with + + + align:start position:0% +these matrices have elements with +different units or different + + align:start position:0% +different units or different + + + align:start position:0% +different units or different +dimensionality when you expand the + + align:start position:0% +dimensionality when you expand the + + + align:start position:0% +dimensionality when you expand the +matrix to get the you know to evaluate + + align:start position:0% +matrix to get the you know to evaluate + + + align:start position:0% +matrix to get the you know to evaluate +when you expand the determinant that's + + align:start position:0% +when you expand the determinant that's + + + align:start position:0% +when you expand the determinant that's +supposed to be a number + + align:start position:0% +supposed to be a number + + + align:start position:0% +supposed to be a number +and in that expansion of the determinant + + align:start position:0% +and in that expansion of the determinant + + + align:start position:0% +and in that expansion of the determinant +you're multiplying a whole bunch of + + align:start position:0% +you're multiplying a whole bunch of + + + align:start position:0% +you're multiplying a whole bunch of +numbers and every term in that sum of + + align:start position:0% +numbers and every term in that sum of + + + align:start position:0% +numbers and every term in that sum of +products + + align:start position:0% +products + + + align:start position:0% +products +has the same dimensionality whether you + + align:start position:0% +has the same dimensionality whether you + + + align:start position:0% +has the same dimensionality whether you +do this or not + + align:start position:0% +do this or not + + + align:start position:0% +do this or not +but it's a good way of checking to see + + align:start position:0% +but it's a good way of checking to see + + + align:start position:0% +but it's a good way of checking to see +whether you've made a mistake + + align:start position:0% +whether you've made a mistake + + + align:start position:0% +whether you've made a mistake +if + + align:start position:0% +if + + + align:start position:0% +if +you know some + + align:start position:0% +you know some + + + align:start position:0% +you know some +element in your in one of the matrices + + align:start position:0% +element in your in one of the matrices + + + align:start position:0% +element in your in one of the matrices +has the wrong dimensionality okay so + + align:start position:0% + + + + align:start position:0% + +we can do this or we cannot do that as + + align:start position:0% +we can do this or we cannot do that as + + + align:start position:0% +we can do this or we cannot do that as +you wish + + align:start position:0% +you wish + + + align:start position:0% +you wish +okay so + + align:start position:0% +okay so + + + align:start position:0% +okay so +first step was + + align:start position:0% +first step was + + + align:start position:0% +first step was +figuring out these little st alphas + + align:start position:0% +figuring out these little st alphas + + + align:start position:0% +figuring out these little st alphas +because we want to draw pictures of the + + align:start position:0% +because we want to draw pictures of the + + + align:start position:0% +because we want to draw pictures of the +displacements + + align:start position:0% +displacements + + + align:start position:0% +displacements +the next step is to + + align:start position:0% +the next step is to + + + align:start position:0% +the next step is to +compute + + align:start position:0% +compute + + + align:start position:0% +compute +what's called the g matrix + + align:start position:0% + + + + align:start position:0% + +and this is a matrix that contains + + align:start position:0% +and this is a matrix that contains + + + align:start position:0% +and this is a matrix that contains +masses and geometry + + align:start position:0% +masses and geometry + + + align:start position:0% +masses and geometry +and it's used to uh + + align:start position:0% +and it's used to uh + + + align:start position:0% +and it's used to uh +evaluate the contribution of the kinetic + + align:start position:0% +evaluate the contribution of the kinetic + + + align:start position:0% +evaluate the contribution of the kinetic +energy to the total hamiltonian + + align:start position:0% + + + + align:start position:0% + +now + + align:start position:0% +now + + + align:start position:0% +now +there are a limited this is so beautiful + + align:start position:0% +there are a limited this is so beautiful + + + align:start position:0% +there are a limited this is so beautiful +i get i get a little thrill every time i + + align:start position:0% +i get i get a little thrill every time i + + + align:start position:0% +i get i get a little thrill every time i +look at this when we're worried about + + align:start position:0% +look at this when we're worried about + + + align:start position:0% +look at this when we're worried about +the vibrations of polyatomic molecules + + align:start position:0% +the vibrations of polyatomic molecules + + + align:start position:0% +the vibrations of polyatomic molecules +when we talk about internal + + align:start position:0% +when we talk about internal + + + align:start position:0% +when we talk about internal +displacements they involve a very small + + align:start position:0% +displacements they involve a very small + + + align:start position:0% +displacements they involve a very small +number of atoms two first stretch three + + align:start position:0% +number of atoms two first stretch three + + + align:start position:0% +number of atoms two first stretch three +for a bend + + align:start position:0% +for a bend + + + align:start position:0% +for a bend +uh four for a torsion + + align:start position:0% +uh four for a torsion + + + align:start position:0% +uh four for a torsion +uh and then that's you could have much + + align:start position:0% +uh and then that's you could have much + + + align:start position:0% +uh and then that's you could have much +much bigger molecules than that + + align:start position:0% +much bigger molecules than that + + + align:start position:0% +much bigger molecules than that +yet + + align:start position:0% +yet + + + align:start position:0% +yet +uh there is a limited number of + + align:start position:0% +uh there is a limited number of + + + align:start position:0% +uh there is a limited number of +topological cases and if you're clever + + align:start position:0% +topological cases and if you're clever + + + align:start position:0% +topological cases and if you're clever +with vector analysis you can work out + + align:start position:0% +with vector analysis you can work out + + + align:start position:0% +with vector analysis you can work out +all of them + + align:start position:0% +all of them + + + align:start position:0% +all of them +and some of them are pretty evil the + + align:start position:0% +and some of them are pretty evil the + + + align:start position:0% +and some of them are pretty evil the +torsions are terrible + + align:start position:0% +torsions are terrible + + + align:start position:0% +torsions are terrible +especially torsions combined with other + + align:start position:0% +especially torsions combined with other + + + align:start position:0% +especially torsions combined with other +things but it can be done and that has + + align:start position:0% +things but it can be done and that has + + + align:start position:0% +things but it can be done and that has +been done + + align:start position:0% +been done + + + align:start position:0% +been done +and so + + align:start position:0% +and so + + + align:start position:0% +and so +the papers by + + align:start position:0% +the papers by + + + align:start position:0% +the papers by +theseus and the book by wilson deceased + + align:start position:0% +theseus and the book by wilson deceased + + + align:start position:0% +theseus and the book by wilson deceased +and cross it's all done there + + align:start position:0% + + + + align:start position:0% + +and so + + align:start position:0% +and so + + + align:start position:0% +and so +then you don't want to have to do this + + align:start position:0% +then you don't want to have to do this + + + align:start position:0% +then you don't want to have to do this +you want to be able to look up + + align:start position:0% +you want to be able to look up + + + align:start position:0% +you want to be able to look up +all of the relevant elements of this g + + align:start position:0% +all of the relevant elements of this g + + + align:start position:0% +all of the relevant elements of this g +matrix + + align:start position:0% +matrix + + + align:start position:0% +matrix +expressed in terms of the things you + + align:start position:0% +expressed in terms of the things you + + + align:start position:0% +expressed in terms of the things you +know + + align:start position:0% +know + + + align:start position:0% +know +and + + align:start position:0% +and + + + align:start position:0% +and +because it's a little bit complicated in + + align:start position:0% +because it's a little bit complicated in + + + align:start position:0% +because it's a little bit complicated in +general the + + align:start position:0% +general the + + + align:start position:0% +general the +matrix the elements of this g matrix are + + align:start position:0% +matrix the elements of this g matrix are + + + align:start position:0% +matrix the elements of this g matrix are +tabulated + + align:start position:0% +tabulated + + + align:start position:0% +tabulated +in a kind of code + + align:start position:0% +in a kind of code + + + align:start position:0% +in a kind of code +it's a very elegant code + + align:start position:0% +it's a very elegant code + + + align:start position:0% +it's a very elegant code +uh but it's it it's it's easy to make + + align:start position:0% +uh but it's it it's it's easy to make + + + align:start position:0% +uh but it's it it's it's easy to make +mistakes in interpreting those elements + + align:start position:0% +mistakes in interpreting those elements + + + align:start position:0% +mistakes in interpreting those elements +so + + align:start position:0% +so + + + align:start position:0% +so +there are more than four types of uh + + align:start position:0% +there are more than four types of uh + + + align:start position:0% +there are more than four types of uh +elements of the g matrix the simplest + + align:start position:0% +elements of the g matrix the simplest + + + align:start position:0% +elements of the g matrix the simplest +one is + + align:start position:0% +one is + + + align:start position:0% +one is +something that's done like this + + align:start position:0% +something that's done like this + + + align:start position:0% +something that's done like this +rr just means two stretches + + align:start position:0% +rr just means two stretches + + + align:start position:0% +rr just means two stretches +now + + align:start position:0% +now + + + align:start position:0% +now +the elements are not tabulated with r + + align:start position:0% +the elements are not tabulated with r + + + align:start position:0% +the elements are not tabulated with r +and r prime it just means it's a stretch + + align:start position:0% +and r prime it just means it's a stretch + + + align:start position:0% +and r prime it just means it's a stretch +stretch interaction it could be diagonal + + align:start position:0% +stretch interaction it could be diagonal + + + align:start position:0% +stretch interaction it could be diagonal +could be off diagonal and two means two + + align:start position:0% +could be off diagonal and two means two + + + align:start position:0% +could be off diagonal and two means two +atoms that means it's the the element + + align:start position:0% +atoms that means it's the the element + + + align:start position:0% +atoms that means it's the the element +involving the same two atoms + + align:start position:0% +involving the same two atoms + + + align:start position:0% +involving the same two atoms +uh + + align:start position:0% +uh + + + align:start position:0% +uh +twice and there is a diagram + + align:start position:0% + + + + align:start position:0% + +that + + align:start position:0% +that + + + align:start position:0% +that +uh + + align:start position:0% +uh + + + align:start position:0% +uh +goes with this symbol + + align:start position:0% +goes with this symbol + + + align:start position:0% +goes with this symbol +and this just says okay we have atom one + + align:start position:0% +and this just says okay we have atom one + + + align:start position:0% +and this just says okay we have atom one +and atom two and two circles are on atom + + align:start position:0% +and atom two and two circles are on atom + + + align:start position:0% +and atom two and two circles are on atom +one two circles around atom two means + + align:start position:0% +one two circles around atom two means + + + align:start position:0% +one two circles around atom two means +that + + align:start position:0% +that + + + align:start position:0% +that +this is a matrix element between two + + align:start position:0% +this is a matrix element between two + + + align:start position:0% +this is a matrix element between two +internal displacements the same two + + align:start position:0% +internal displacements the same two + + + align:start position:0% +internal displacements the same two +atoms are involved in both + + align:start position:0% +atoms are involved in both + + + align:start position:0% +atoms are involved in both +uh + + align:start position:0% +uh + + + align:start position:0% +uh +are the + + align:start position:0% +are the + + + align:start position:0% +are the +involved here and here now we could + + align:start position:0% +involved here and here now we could + + + align:start position:0% +involved here and here now we could +uh if we had something where + + align:start position:0% +uh if we had something where + + + align:start position:0% +uh if we had something where +we had + + align:start position:0% +we had + + + align:start position:0% +we had +three atoms + + align:start position:0% +three atoms + + + align:start position:0% +three atoms +and two circles around one + + align:start position:0% +and two circles around one + + + align:start position:0% +and two circles around one +that would be an interaction between one + + align:start position:0% +that would be an interaction between one + + + align:start position:0% +that would be an interaction between one +stretch here and one stretch here + + align:start position:0% +stretch here and one stretch here + + + align:start position:0% +stretch here and one stretch here +that would still + + align:start position:0% +that would still + + + align:start position:0% +that would still +be + + align:start position:0% +be + + + align:start position:0% +be +rr but it would have a one up there + + align:start position:0% + + + + align:start position:0% + +and so it could be straight straight it + + align:start position:0% +and so it could be straight straight it + + + align:start position:0% +and so it could be straight straight it +could be bent and we + + align:start position:0% +could be bent and we + + + align:start position:0% +could be bent and we +these things tend to have + + align:start position:0% +these things tend to have + + + align:start position:0% +these things tend to have +numbers on them because the elements + + align:start position:0% +numbers on them because the elements + + + align:start position:0% +numbers on them because the elements +that are tabulated + + align:start position:0% +that are tabulated + + + align:start position:0% +that are tabulated +uh make use of those numbers and so it's + + align:start position:0% +uh make use of those numbers and so it's + + + align:start position:0% +uh make use of those numbers and so it's +a good thing + + align:start position:0% +a good thing + + + align:start position:0% +a good thing +to + + align:start position:0% + + + + align:start position:0% + +exploit the numbers + + align:start position:0% +exploit the numbers + + + align:start position:0% +exploit the numbers +we could have + + align:start position:0% +we could have + + + align:start position:0% +we could have +three + + align:start position:0% +three + + + align:start position:0% +three +atoms + + align:start position:0% +atoms + + + align:start position:0% +atoms +connected + + align:start position:0% +connected + + + align:start position:0% +connected +circles + + align:start position:0% +circles + + + align:start position:0% +circles +like that + + align:start position:0% +like that + + + align:start position:0% +like that +and you know immediately that the only + + align:start position:0% +and you know immediately that the only + + + align:start position:0% +and you know immediately that the only +way three atoms could be involved in + + align:start position:0% +way three atoms could be involved in + + + align:start position:0% +way three atoms could be involved in +both motions would be for a diagonal + + align:start position:0% +both motions would be for a diagonal + + + align:start position:0% +both motions would be for a diagonal +bend bend interaction and that would + + align:start position:0% +bend bend interaction and that would + + + align:start position:0% +bend bend interaction and that would +correspond to three atoms + + align:start position:0% +correspond to three atoms + + + align:start position:0% +correspond to three atoms +and uh + + align:start position:0% +and uh + + + align:start position:0% +and uh +phi five + + align:start position:0% + + + + align:start position:0% + +and again + + align:start position:0% +and again + + + align:start position:0% +and again +they should be numbered three + + align:start position:0% +they should be numbered three + + + align:start position:0% +they should be numbered three +now i don't know why + + align:start position:0% +now i don't know why + + + align:start position:0% +now i don't know why +the numbering is topologically different + + align:start position:0% +the numbering is topologically different + + + align:start position:0% +the numbering is topologically different +for this and it's possible that i + + align:start position:0% +for this and it's possible that i + + + align:start position:0% +for this and it's possible that i +screwed up on one of them + + align:start position:0% +screwed up on one of them + + + align:start position:0% +screwed up on one of them +and + + align:start position:0% +and + + + align:start position:0% +and +we could have a bend stretch interaction + + align:start position:0% +we could have a bend stretch interaction + + + align:start position:0% +we could have a bend stretch interaction +where we'd have three + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +uh + + align:start position:0% +uh + + + align:start position:0% +uh +so here we have a bending motion + + align:start position:0% +so here we have a bending motion + + + align:start position:0% +so here we have a bending motion +between these three involving these + + align:start position:0% +between these three involving these + + + align:start position:0% +between these three involving these +three atoms and a stretch involving two + + align:start position:0% +three atoms and a stretch involving two + + + align:start position:0% +three atoms and a stretch involving two +and so + + align:start position:0% +and so + + + align:start position:0% +and so +that would be a g2 + + align:start position:0% +that would be a g2 + + + align:start position:0% +that would be a g2 +because there's two atoms in common + + align:start position:0% +because there's two atoms in common + + + align:start position:0% +because there's two atoms in common +and it would be in our + + align:start position:0% +and it would be in our + + + align:start position:0% +and it would be in our +whoops an r5 + + align:start position:0% +whoops an r5 + + + align:start position:0% +whoops an r5 +okay so there are more symbols than this + + align:start position:0% +okay so there are more symbols than this + + + align:start position:0% +okay so there are more symbols than this +in the + + align:start position:0% +in the + + + align:start position:0% +in the +table tables but uh i think this is so + + align:start position:0% +table tables but uh i think this is so + + + align:start position:0% +table tables but uh i think this is so +beautiful + + align:start position:0% + + + + align:start position:0% + +it's even worse uh because + + align:start position:0% +it's even worse uh because + + + align:start position:0% +it's even worse uh because +then when you go + + align:start position:0% +then when you go + + + align:start position:0% +then when you go +to look up + + align:start position:0% +to look up + + + align:start position:0% +to look up +the elements g11 + + align:start position:0% +the elements g11 + + + align:start position:0% +the elements g11 +or well g one one + + align:start position:0% +or well g one one + + + align:start position:0% +or well g one one +the + + align:start position:0% +the + + + align:start position:0% +the +uh suppose we have uh + + align:start position:0% +uh suppose we have uh + + + align:start position:0% +uh suppose we have uh +uh the one internal coordinate is a + + align:start position:0% +uh the one internal coordinate is a + + + align:start position:0% +uh the one internal coordinate is a +stretch well g one one + + align:start position:0% +stretch well g one one + + + align:start position:0% +stretch well g one one +is then equal to + + align:start position:0% +is then equal to + + + align:start position:0% +is then equal to +g + + align:start position:0% +g + + + align:start position:0% +g + + align:start position:0% + + + align:start position:0% +r 3 1 r + + align:start position:0% +r 3 1 r + + + align:start position:0% +r 3 1 r +3 1. + + align:start position:0% +3 1. + + + align:start position:0% +3 1. +in other words it's two identical + + align:start position:0% +in other words it's two identical + + + align:start position:0% +in other words it's two identical +stretches + + align:start position:0% +stretches + + + align:start position:0% +stretches +and then you're told to to write mu 1 + + align:start position:0% +and then you're told to to write mu 1 + + + align:start position:0% +and then you're told to to write mu 1 +plus u2 + + align:start position:0% +plus u2 + + + align:start position:0% +plus u2 +and this is 1 over the mass of atom one + + align:start position:0% +and this is 1 over the mass of atom one + + + align:start position:0% +and this is 1 over the mass of atom one +and this is one over the mass of atom + + align:start position:0% +and this is one over the mass of atom + + + align:start position:0% +and this is one over the mass of atom +two one place where you make mistakes mu + + align:start position:0% +two one place where you make mistakes mu + + + align:start position:0% +two one place where you make mistakes mu +sounds like mass + + align:start position:0% +sounds like mass + + + align:start position:0% +sounds like mass +but it's one reciprocal mess + + align:start position:0% +but it's one reciprocal mess + + + align:start position:0% +but it's one reciprocal mess +it's easy to screw up + + align:start position:0% + + + + align:start position:0% + +uh + + align:start position:0% +uh + + + align:start position:0% +uh +anyway i'm not going to write more of + + align:start position:0% +anyway i'm not going to write more of + + + align:start position:0% +anyway i'm not going to write more of +them another place where you screw up is + + align:start position:0% +them another place where you screw up is + + + align:start position:0% +them another place where you screw up is +often distances appear and they appear + + align:start position:0% +often distances appear and they appear + + + align:start position:0% +often distances appear and they appear +with the symbol rho rather than r + + align:start position:0% +with the symbol rho rather than r + + + align:start position:0% +with the symbol rho rather than r +and those are reciprocal distances + + align:start position:0% + + + + align:start position:0% + +so there are two places where you could + + align:start position:0% +so there are two places where you could + + + align:start position:0% +so there are two places where you could +be led to think you understand + + align:start position:0% +be led to think you understand + + + align:start position:0% +be led to think you understand +especially if you're using a table you + + align:start position:0% +especially if you're using a table you + + + align:start position:0% +especially if you're using a table you +didn't make + + align:start position:0% +didn't make + + + align:start position:0% +didn't make +but + + align:start position:0% +but + + + align:start position:0% +but +once you have + + align:start position:0% +once you have + + + align:start position:0% +once you have +considered that it's done + + align:start position:0% +considered that it's done + + + align:start position:0% +considered that it's done +okay so + + align:start position:0% +okay so + + + align:start position:0% +okay so +you have this + + align:start position:0% +you have this + + + align:start position:0% +you have this +g matrix which you need to describe the + + align:start position:0% +g matrix which you need to describe the + + + align:start position:0% +g matrix which you need to describe the +kinetic energy of the vibrating molecule + + align:start position:0% +kinetic energy of the vibrating molecule + + + align:start position:0% +kinetic energy of the vibrating molecule +and + + align:start position:0% +and + + + align:start position:0% +and +uh once you have it in symbolic form you + + align:start position:0% +uh once you have it in symbolic form you + + + align:start position:0% +uh once you have it in symbolic form you +can put in the masses and the distances + + align:start position:0% +can put in the masses and the distances + + + align:start position:0% +can put in the masses and the distances +and the angles and you can make this a + + align:start position:0% +and the angles and you can make this a + + + align:start position:0% +and the angles and you can make this a +numerical matrix + + align:start position:0% +numerical matrix + + + align:start position:0% +numerical matrix +and so + + align:start position:0% +and so + + + align:start position:0% +and so +you can derive + + align:start position:0% +you can derive + + + align:start position:0% +you can derive +the numerical g matrix + + align:start position:0% +the numerical g matrix + + + align:start position:0% +the numerical g matrix +and for water it's a three by three + + align:start position:0% +and for water it's a three by three + + + align:start position:0% +and for water it's a three by three +matrix the elements have different units + + align:start position:0% +matrix the elements have different units + + + align:start position:0% +matrix the elements have different units +and the elements not only have different + + align:start position:0% +and the elements not only have different + + + align:start position:0% +and the elements not only have different +units i'm using forbidden units of + + align:start position:0% +units i'm using forbidden units of + + + align:start position:0% +units i'm using forbidden units of +nines milodynes most of you don't even + + align:start position:0% +nines milodynes most of you don't even + + + align:start position:0% +nines milodynes most of you don't even +know i gave a lecture in france a few + + align:start position:0% +know i gave a lecture in france a few + + + align:start position:0% +know i gave a lecture in france a few +years ago and i was nearly killed when i + + align:start position:0% +years ago and i was nearly killed when i + + + align:start position:0% +years ago and i was nearly killed when i +started talking about dines + + align:start position:0% +started talking about dines + + + align:start position:0% +started talking about dines +and + + align:start position:0% + + + + align:start position:0% + +and ergs rather than + + align:start position:0% +and ergs rather than + + + align:start position:0% +and ergs rather than +newtons and jewels and + + align:start position:0% +newtons and jewels and + + + align:start position:0% +newtons and jewels and +but + + align:start position:0% +but + + + align:start position:0% +but +anyway + + align:start position:0% +anyway + + + align:start position:0% +anyway +this is an old subject and i learned it + + align:start position:0% +this is an old subject and i learned it + + + align:start position:0% +this is an old subject and i learned it +a long time ago my notes are have dines + + align:start position:0% +a long time ago my notes are have dines + + + align:start position:0% +a long time ago my notes are have dines +but the important thing is that you can + + align:start position:0% +but the important thing is that you can + + + align:start position:0% +but the important thing is that you can +convert the uh + + align:start position:0% +convert the uh + + + align:start position:0% +convert the uh +units to something uh uh + + align:start position:0% +units to something uh uh + + + align:start position:0% +units to something uh uh +more universal and uh + + align:start position:0% +more universal and uh + + + align:start position:0% +more universal and uh +so anyway you you you get the g matrix + + align:start position:0% +so anyway you you you get the g matrix + + + align:start position:0% +so anyway you you you get the g matrix +and the + + align:start position:0% +and the + + + align:start position:0% +and the +f matrix now the f matrix is the matrix + + align:start position:0% +f matrix now the f matrix is the matrix + + + align:start position:0% +f matrix now the f matrix is the matrix +of force constants + + align:start position:0% +of force constants + + + align:start position:0% +of force constants +uh + + align:start position:0% +uh + + + align:start position:0% +uh +what are the + + align:start position:0% +what are the + + + align:start position:0% +what are the +um + + align:start position:0% + + + + align:start position:0% + +what force does it take + + align:start position:0% +what force does it take + + + align:start position:0% +what force does it take +to stretch the ver to change the various + + align:start position:0% +to stretch the ver to change the various + + + align:start position:0% +to stretch the ver to change the various +internal coordinates + + align:start position:0% +internal coordinates + + + align:start position:0% +internal coordinates +and one can get these + + align:start position:0% +and one can get these + + + align:start position:0% +and one can get these +uh elements of the force constant matrix + + align:start position:0% +uh elements of the force constant matrix + + + align:start position:0% +uh elements of the force constant matrix +by fitting a lot of spectra + + align:start position:0% +by fitting a lot of spectra + + + align:start position:0% +by fitting a lot of spectra +or by doing an initial calculation but + + align:start position:0% +or by doing an initial calculation but + + + align:start position:0% +or by doing an initial calculation but +when you do and i've initial calculation + + align:start position:0% +when you do and i've initial calculation + + + align:start position:0% +when you do and i've initial calculation +what you get + + align:start position:0% +what you get + + + align:start position:0% +what you get +is not a + + align:start position:0% +is not a + + + align:start position:0% +is not a +three n minus six by three n minus six + + align:start position:0% +three n minus six by three n minus six + + + align:start position:0% +three n minus six by three n minus six +dimensional force constant matrix you + + align:start position:0% +dimensional force constant matrix you + + + align:start position:0% +dimensional force constant matrix you +get a three n by three n matrix and you + + align:start position:0% +get a three n by three n matrix and you + + + align:start position:0% +get a three n by three n matrix and you +have to do a transformation to reduce it + + align:start position:0% +have to do a transformation to reduce it + + + align:start position:0% +have to do a transformation to reduce it +to this + + align:start position:0% +to this + + + align:start position:0% +to this +okay but that's if you have the s's then + + align:start position:0% +okay but that's if you have the s's then + + + align:start position:0% +okay but that's if you have the s's then +you can do that i'm just not going to + + align:start position:0% +you can do that i'm just not going to + + + align:start position:0% +you can do that i'm just not going to +talk about it + + align:start position:0% +talk about it + + + align:start position:0% +talk about it +now in this case for water we have three + + align:start position:0% +now in this case for water we have three + + + align:start position:0% +now in this case for water we have three +normal mode frequencies + + align:start position:0% +normal mode frequencies + + + align:start position:0% +normal mode frequencies +and it's a three by three matrix and so + + align:start position:0% +and it's a three by three matrix and so + + + align:start position:0% +and it's a three by three matrix and so +uh in this three by three matrix we have + + align:start position:0% +uh in this three by three matrix we have + + + align:start position:0% +uh in this three by three matrix we have +six linearly independent elements + + align:start position:0% +six linearly independent elements + + + align:start position:0% +six linearly independent elements +not uh and that's too many + + align:start position:0% +not uh and that's too many + + + align:start position:0% +not uh and that's too many +well g and f are both symmetric matrices + + align:start position:0% +well g and f are both symmetric matrices + + + align:start position:0% +well g and f are both symmetric matrices +and so + + align:start position:0% +and so + + + align:start position:0% +and so +how do you get all six + + align:start position:0% +how do you get all six + + + align:start position:0% +how do you get all six +uh elements of the force constant matrix + + align:start position:0% +uh elements of the force constant matrix + + + align:start position:0% +uh elements of the force constant matrix +uh well you fit isotopic spectra or you + + align:start position:0% +uh well you fit isotopic spectra or you + + + align:start position:0% +uh well you fit isotopic spectra or you +do complicated stuff and but you can do + + align:start position:0% +do complicated stuff and but you can do + + + align:start position:0% +do complicated stuff and but you can do +that you can eventually get six elements + + align:start position:0% +that you can eventually get six elements + + + align:start position:0% +that you can eventually get six elements +it's not as trivial as you might think + + align:start position:0% +it's not as trivial as you might think + + + align:start position:0% +it's not as trivial as you might think +because + + align:start position:0% + + + + align:start position:0% + +what you want is + + align:start position:0% + + + + align:start position:0% + +is + + align:start position:0% +is + + + align:start position:0% +is +the harmonic + + align:start position:0% +the harmonic + + + align:start position:0% +the harmonic +force constant + + align:start position:0% +force constant + + + align:start position:0% +force constant +and what you get in the spectrum is a + + align:start position:0% +and what you get in the spectrum is a + + + align:start position:0% +and what you get in the spectrum is a +difference in energy between v equals + + align:start position:0% +difference in energy between v equals + + + align:start position:0% +difference in energy between v equals +zero and v equals one + + align:start position:0% +zero and v equals one + + + align:start position:0% +zero and v equals one +and if it's a polyatomic if it's not a + + align:start position:0% +and if it's a polyatomic if it's not a + + + align:start position:0% +and if it's a polyatomic if it's not a +diatomic molecule there's cross and + + align:start position:0% +diatomic molecule there's cross and + + + align:start position:0% +diatomic molecule there's cross and +harmonicities between all the modes and + + align:start position:0% +harmonicities between all the modes and + + + align:start position:0% +harmonicities between all the modes and +somehow you have to back that all out + + align:start position:0% +somehow you have to back that all out + + + align:start position:0% +somehow you have to back that all out +and it's not so trivial to do it to get + + align:start position:0% +and it's not so trivial to do it to get + + + align:start position:0% +and it's not so trivial to do it to get +this from the spectrum but in principle + + align:start position:0% +this from the spectrum but in principle + + + align:start position:0% +this from the spectrum but in principle +you could imagine you could get that + + align:start position:0% +you could imagine you could get that + + + align:start position:0% +you could imagine you could get that +experimentally + + align:start position:0% +experimentally + + + align:start position:0% +experimentally +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so this is a symmetric matrix and this + + align:start position:0% +so this is a symmetric matrix and this + + + align:start position:0% +so this is a symmetric matrix and this +is a symmetric matrix + + align:start position:0% +is a symmetric matrix + + + align:start position:0% +is a symmetric matrix +what we want is this combination of g + + align:start position:0% +what we want is this combination of g + + + align:start position:0% +what we want is this combination of g +and f + + align:start position:0% + + + + align:start position:0% + +and this is the matrix + + align:start position:0% +and this is the matrix + + + align:start position:0% +and this is the matrix +whose eigenvalues we want in order to + + align:start position:0% +whose eigenvalues we want in order to + + + align:start position:0% +whose eigenvalues we want in order to +determine the normal mode frequencies + + align:start position:0% +determine the normal mode frequencies + + + align:start position:0% +determine the normal mode frequencies +and whose eigenvectors we want in order + + align:start position:0% +and whose eigenvectors we want in order + + + align:start position:0% +and whose eigenvectors we want in order +to determine the forms of the normal + + align:start position:0% +to determine the forms of the normal + + + align:start position:0% +to determine the forms of the normal +modes + + align:start position:0% +modes + + + align:start position:0% +modes +so if we have these two matrices + + align:start position:0% +so if we have these two matrices + + + align:start position:0% +so if we have these two matrices +evaluate expressed in numerical form + + align:start position:0% +evaluate expressed in numerical form + + + align:start position:0% +evaluate expressed in numerical form +it's trivial to multiply them + + align:start position:0% +it's trivial to multiply them + + + align:start position:0% +it's trivial to multiply them +symmetric matrix symmetric matrix + + align:start position:0% +symmetric matrix symmetric matrix + + + align:start position:0% +symmetric matrix symmetric matrix +not a symmetric matrix + + align:start position:0% +not a symmetric matrix + + + align:start position:0% +not a symmetric matrix +that's a + + align:start position:0% +that's a + + + align:start position:0% +that's a +surprise + + align:start position:0% +surprise + + + align:start position:0% +surprise +but you can prove that it's not + + align:start position:0% +but you can prove that it's not + + + align:start position:0% +but you can prove that it's not +symmetric just by taking two symmetric + + align:start position:0% +symmetric just by taking two symmetric + + + align:start position:0% +symmetric just by taking two symmetric +two by twos and multiplying them you + + align:start position:0% +two by twos and multiplying them you + + + align:start position:0% +two by twos and multiplying them you +discover + + align:start position:0% +discover + + + align:start position:0% +discover +you're not guaranteed and + + align:start position:0% +you're not guaranteed and + + + align:start position:0% +you're not guaranteed and +when you have a not symmetric matrix + + align:start position:0% +when you have a not symmetric matrix + + + align:start position:0% +when you have a not symmetric matrix +you cannot diagonalize that by a unitary + + align:start position:0% +you cannot diagonalize that by a unitary + + + align:start position:0% +you cannot diagonalize that by a unitary +transformation + + align:start position:0% +transformation + + + align:start position:0% +transformation +you diagonalize it by a similarity + + align:start position:0% +you diagonalize it by a similarity + + + align:start position:0% +you diagonalize it by a similarity +transformation + + align:start position:0% +transformation + + + align:start position:0% +transformation +the computer does it you don't care how + + align:start position:0% +the computer does it you don't care how + + + align:start position:0% +the computer does it you don't care how +it does it you just have to instruct it + + align:start position:0% +it does it you just have to instruct it + + + align:start position:0% +it does it you just have to instruct it +slightly differently and you want to + + align:start position:0% +slightly differently and you want to + + + align:start position:0% +slightly differently and you want to +know what transformation it used to find + + align:start position:0% +know what transformation it used to find + + + align:start position:0% +know what transformation it used to find +the eigenvalues of this matrix because + + align:start position:0% +the eigenvalues of this matrix because + + + align:start position:0% +the eigenvalues of this matrix because +you're going to use them + + align:start position:0% + + + + align:start position:0% + +okay so + + align:start position:0% + + + + align:start position:0% + +for the water example we have the + + align:start position:0% +for the water example we have the + + + align:start position:0% +for the water example we have the +numerical g and f matrices we have gf + + align:start position:0% +numerical g and f matrices we have gf + + + align:start position:0% +numerical g and f matrices we have gf +and + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +as soon as we have this we can write the + + align:start position:0% +as soon as we have this we can write the + + + align:start position:0% +as soon as we have this we can write the +secular equation and the the + + align:start position:0% +secular equation and the the + + + align:start position:0% +secular equation and the the +roots of the secular equation are three + + align:start position:0% +roots of the secular equation are three + + + align:start position:0% +roots of the secular equation are three +numbers also with three different units + + align:start position:0% +numbers also with three different units + + + align:start position:0% +numbers also with three different units +well that's that's not true no there are + + align:start position:0% +well that's that's not true no there are + + + align:start position:0% +well that's that's not true no there are +three numbers with the same units + + align:start position:0% +three numbers with the same units + + + align:start position:0% +three numbers with the same units +and converting + + align:start position:0% +and converting + + + align:start position:0% +and converting +to useful units they all have units of + + align:start position:0% +to useful units they all have units of + + + align:start position:0% +to useful units they all have units of +seconds and minus two + + align:start position:0% +seconds and minus two + + + align:start position:0% +seconds and minus two +and what we want so we we have three + + align:start position:0% +and what we want so we we have three + + + align:start position:0% +and what we want so we we have three +eigenvalues + + align:start position:0% +eigenvalues + + + align:start position:0% +eigenvalues +lambda one lambda two lambda three + + align:start position:0% +lambda one lambda two lambda three + + + align:start position:0% +lambda one lambda two lambda three +and what we want is the square roots of + + align:start position:0% +and what we want is the square roots of + + + align:start position:0% +and what we want is the square roots of +these things because those will be + + align:start position:0% +these things because those will be + + + align:start position:0% +these things because those will be +frequencies + + align:start position:0% +frequencies + + + align:start position:0% +frequencies +and but we're spectroscopists and so we + + align:start position:0% +and but we're spectroscopists and so we + + + align:start position:0% +and but we're spectroscopists and so we +don't want frequencies we want + + align:start position:0% +don't want frequencies we want + + + align:start position:0% +don't want frequencies we want +reciprocal centimeters and so we divide + + align:start position:0% +reciprocal centimeters and so we divide + + + align:start position:0% +reciprocal centimeters and so we divide +by the speed of light + + align:start position:0% +by the speed of light + + + align:start position:0% +by the speed of light +so + + align:start position:0% + + + + align:start position:0% + +we get + + align:start position:0% +we get + + + align:start position:0% +we get +uh + + align:start position:0% +uh + + + align:start position:0% +uh +three eigenvalues and the three + + align:start position:0% +three eigenvalues and the three + + + align:start position:0% +three eigenvalues and the three +eigenvectors that correspond to these + + align:start position:0% +eigenvectors that correspond to these + + + align:start position:0% +eigenvectors that correspond to these +eigenvalues + + align:start position:0% +eigenvalues + + + align:start position:0% +eigenvalues +and they have the frequencies + + align:start position:0% +and they have the frequencies + + + align:start position:0% +and they have the frequencies +uh 39 + + align:start position:0% +uh 39 + + + align:start position:0% +uh 39 + + align:start position:0% + + + align:start position:0% +reciprocal centimeters + + align:start position:0% +reciprocal centimeters + + + align:start position:0% +reciprocal centimeters + + align:start position:0% + + + align:start position:0% + + align:start position:0% + + + + align:start position:0% + +and 1648 + + align:start position:0% + + + + align:start position:0% + +okay so that's what comes out + + align:start position:0% +okay so that's what comes out + + + align:start position:0% +okay so that's what comes out +and these are in fact the normal mode + + align:start position:0% +and these are in fact the normal mode + + + align:start position:0% +and these are in fact the normal mode +frequencies of water + + align:start position:0% +frequencies of water + + + align:start position:0% +frequencies of water +and + + align:start position:0% +and + + + align:start position:0% +and +but there's one thing that's wrong + + align:start position:0% +but there's one thing that's wrong + + + align:start position:0% +but there's one thing that's wrong +they're numbered wrong + + align:start position:0% + + + + align:start position:0% + +the computer solves this problem + + align:start position:0% +the computer solves this problem + + + align:start position:0% +the computer solves this problem +and + + align:start position:0% +and + + + align:start position:0% +and +it numbers or + + align:start position:0% +it numbers or + + + align:start position:0% +it numbers or +it gives you a list of eigenvalues in + + align:start position:0% +it gives you a list of eigenvalues in + + + align:start position:0% +it gives you a list of eigenvalues in +some order and you might call them one + + align:start position:0% +some order and you might call them one + + + align:start position:0% +some order and you might call them one +two three + + align:start position:0% +two three + + + align:start position:0% +two three +it doesn't know anything about + + align:start position:0% +it doesn't know anything about + + + align:start position:0% +it doesn't know anything about +spectroscopic conventions because it's + + align:start position:0% +spectroscopic conventions because it's + + + align:start position:0% +spectroscopic conventions because it's +it's it's not a it's a it's a computer + + align:start position:0% +it's it's not a it's a it's a computer + + + align:start position:0% +it's it's not a it's a it's a computer +it's not an insane person + + align:start position:0% +it's not an insane person + + + align:start position:0% +it's not an insane person +there is a spectroscopic convention for + + align:start position:0% +there is a spectroscopic convention for + + + align:start position:0% +there is a spectroscopic convention for +numbering the normal modes of any + + align:start position:0% +numbering the normal modes of any + + + align:start position:0% +numbering the normal modes of any +molecule + + align:start position:0% +molecule + + + align:start position:0% +molecule +and i should talk about that for a + + align:start position:0% +and i should talk about that for a + + + align:start position:0% +and i should talk about that for a +moment + + align:start position:0% +moment + + + align:start position:0% +moment +if you're a spectroscopist + + align:start position:0% +if you're a spectroscopist + + + align:start position:0% +if you're a spectroscopist +and you say i have a molecule say + + align:start position:0% +and you say i have a molecule say + + + align:start position:0% +and you say i have a molecule say +benzene + + align:start position:0% +benzene + + + align:start position:0% +benzene +and i say okay nu18 of benzene is + + align:start position:0% +and i say okay nu18 of benzene is + + + align:start position:0% +and i say okay nu18 of benzene is +something you immediately can figure out + + align:start position:0% +something you immediately can figure out + + + align:start position:0% +something you immediately can figure out +what that + + align:start position:0% +what that + + + align:start position:0% +what that +uh which + + align:start position:0% +uh which + + + align:start position:0% +uh which +uh symmetry species that normal mode has + + align:start position:0% +uh symmetry species that normal mode has + + + align:start position:0% +uh symmetry species that normal mode has +and whether it's predominantly a bend or + + align:start position:0% +and whether it's predominantly a bend or + + + align:start position:0% +and whether it's predominantly a bend or +a stretch + + align:start position:0% +a stretch + + + align:start position:0% +a stretch +maybe not immediately but there is no + + align:start position:0% +maybe not immediately but there is no + + + align:start position:0% +maybe not immediately but there is no +possibility for disagreement + + align:start position:0% +possibility for disagreement + + + align:start position:0% +possibility for disagreement +because the the agree the international + + align:start position:0% +because the the agree the international + + + align:start position:0% +because the the agree the international +convention on how you number the modes + + align:start position:0% +convention on how you number the modes + + + align:start position:0% +convention on how you number the modes +is well established what do you do + + align:start position:0% + + + + align:start position:0% + +well + + align:start position:0% +well + + + align:start position:0% +well +the high the the + + align:start position:0% +the high the the + + + align:start position:0% +the high the the +we have two different things we have + + align:start position:0% +we have two different things we have + + + align:start position:0% +we have two different things we have +frequency + + align:start position:0% +frequency + + + align:start position:0% +frequency +and symmetry + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% + + + + align:start position:0% + +it would be a child child's play if we + + align:start position:0% +it would be a child child's play if we + + + align:start position:0% +it would be a child child's play if we +just took all the eigenvalues of this + + align:start position:0% +just took all the eigenvalues of this + + + align:start position:0% +just took all the eigenvalues of this +matrix + + align:start position:0% +matrix + + + align:start position:0% +matrix +and listed them in numerical order and + + align:start position:0% +and listed them in numerical order and + + + align:start position:0% +and listed them in numerical order and +say the largest one is + + align:start position:0% +say the largest one is + + + align:start position:0% +say the largest one is +mode one and the smallest one is mode + + align:start position:0% +mode one and the smallest one is mode + + + align:start position:0% +mode one and the smallest one is mode +three n minus six + + align:start position:0% +three n minus six + + + align:start position:0% +three n minus six +and that would be a correct thing to do + + align:start position:0% +and that would be a correct thing to do + + + align:start position:0% +and that would be a correct thing to do +for a molecule that has no symmetry + + align:start position:0% +for a molecule that has no symmetry + + + align:start position:0% +for a molecule that has no symmetry +but when there is symmetry + + align:start position:0% +but when there is symmetry + + + align:start position:0% +but when there is symmetry +as there is in water water has uh c2 + + align:start position:0% +as there is in water water has uh c2 + + + align:start position:0% +as there is in water water has uh c2 +symmetry it has reflection planes and + + align:start position:0% +symmetry it has reflection planes and + + + align:start position:0% +symmetry it has reflection planes and +all that sort of good stuff it belongs + + align:start position:0% +all that sort of good stuff it belongs + + + align:start position:0% +all that sort of good stuff it belongs +to what point group + + align:start position:0% + + + + align:start position:0% + +right and c2v has + + align:start position:0% + + + + align:start position:0% + +symmetry species for symmetry species + + align:start position:0% +symmetry species for symmetry species + + + align:start position:0% +symmetry species for symmetry species +and so + + align:start position:0% + + + + align:start position:0% + +what you do + + align:start position:0% +what you do + + + align:start position:0% +what you do +is you first + + align:start position:0% +is you first + + + align:start position:0% +is you first +number the totally symmetric modes in + + align:start position:0% +number the totally symmetric modes in + + + align:start position:0% +number the totally symmetric modes in +order + + align:start position:0% +order + + + align:start position:0% +order +and then you go to the next + + align:start position:0% +and then you go to the next + + + align:start position:0% +and then you go to the next +uh + + align:start position:0% +uh + + + align:start position:0% +uh +there is a convention for which one you + + align:start position:0% +there is a convention for which one you + + + align:start position:0% +there is a convention for which one you +do which you do second it's this one + + align:start position:0% +do which you do second it's this one + + + align:start position:0% +do which you do second it's this one +character no the character is going to + + align:start position:0% +character no the character is going to + + + align:start position:0% +character no the character is going to +be a1 a2 + + align:start position:0% +be a1 a2 + + + align:start position:0% +be a1 a2 +it might be uh and then you would go + + align:start position:0% +it might be uh and then you would go + + + align:start position:0% +it might be uh and then you would go +down the character table but it's a one + + align:start position:0% +down the character table but it's a one + + + align:start position:0% +down the character table but it's a one +then a2 then b1 then b2 + + align:start position:0% +then a2 then b1 then b2 + + + align:start position:0% +then a2 then b1 then b2 +and if we're in c2h it would be a g then + + align:start position:0% +and if we're in c2h it would be a g then + + + align:start position:0% +and if we're in c2h it would be a g then +a u b g then b u there's lots of but + + align:start position:0% +a u b g then b u there's lots of but + + + align:start position:0% +a u b g then b u there's lots of but +once you see what the the idea is you + + align:start position:0% +once you see what the the idea is you + + + align:start position:0% +once you see what the the idea is you +can figure out how + + align:start position:0% +can figure out how + + + align:start position:0% +can figure out how +you + + align:start position:0% +you + + + align:start position:0% +you +uh assign modes to symmetry now you + + align:start position:0% +uh assign modes to symmetry now you + + + align:start position:0% +uh assign modes to symmetry now you +don't know + + align:start position:0% +don't know + + + align:start position:0% +don't know +at the present time for an arbitrary + + align:start position:0% +at the present time for an arbitrary + + + align:start position:0% +at the present time for an arbitrary +molecule how many modes there are + + align:start position:0% +molecule how many modes there are + + + align:start position:0% +molecule how many modes there are +in each symmetry species + + align:start position:0% +in each symmetry species + + + align:start position:0% +in each symmetry species +that is a fairly beautiful and standard + + align:start position:0% +that is a fairly beautiful and standard + + + align:start position:0% +that is a fairly beautiful and standard +problem which i probably well i don't + + align:start position:0% +problem which i probably well i don't + + + align:start position:0% +problem which i probably well i don't +know if i run out of things to talk + + align:start position:0% +know if i run out of things to talk + + + align:start position:0% +know if i run out of things to talk +about i'll do it but it's too easy + + align:start position:0% +about i'll do it but it's too easy + + + align:start position:0% +about i'll do it but it's too easy +and there's also a simple group + + align:start position:0% +and there's also a simple group + + + align:start position:0% +and there's also a simple group +theoretical thing method for deciding + + align:start position:0% +theoretical thing method for deciding + + + align:start position:0% +theoretical thing method for deciding +whether a particular mode is + + align:start position:0% +whether a particular mode is + + + align:start position:0% +whether a particular mode is +predominantly stretch or bend or a + + align:start position:0% +predominantly stretch or bend or a + + + align:start position:0% +predominantly stretch or bend or a +mixture and what kind of stretch or + + align:start position:0% +mixture and what kind of stretch or + + + align:start position:0% +mixture and what kind of stretch or +bends so there's some very nice stuff + + align:start position:0% +bends so there's some very nice stuff + + + align:start position:0% +bends so there's some very nice stuff +that you can do just with group theory + + align:start position:0% +that you can do just with group theory + + + align:start position:0% +that you can do just with group theory +to describe the essential + + align:start position:0% +to describe the essential + + + align:start position:0% +to describe the essential +characteristics of all of the normal + + align:start position:0% +characteristics of all of the normal + + + align:start position:0% +characteristics of all of the normal +modes and so if someone tells you the + + align:start position:0% +modes and so if someone tells you the + + + align:start position:0% +modes and so if someone tells you the +mode number + + align:start position:0% +mode number + + + align:start position:0% +mode number +without too much work all the hard + + align:start position:0% +without too much work all the hard + + + align:start position:0% +without too much work all the hard +all the hard work has been done getting + + align:start position:0% +all the hard work has been done getting + + + align:start position:0% +all the hard work has been done getting +these frequencies + + align:start position:0% +these frequencies + + + align:start position:0% +these frequencies +and + + align:start position:0% +and + + + align:start position:0% +and +if if then that person knows the rules + + align:start position:0% +if if then that person knows the rules + + + align:start position:0% +if if then that person knows the rules +and says this is new 18 + + align:start position:0% +and says this is new 18 + + + align:start position:0% +and says this is new 18 +then you can do the group theory and + + align:start position:0% +then you can do the group theory and + + + align:start position:0% +then you can do the group theory and +figure out what is the essential + + align:start position:0% +figure out what is the essential + + + align:start position:0% +figure out what is the essential +characteristic of that mode + + align:start position:0% +characteristic of that mode + + + align:start position:0% +characteristic of that mode +and that's really very wonderful okay + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% + + + + align:start position:0% + +we diagonalize we get the eigenvalues of + + align:start position:0% +we diagonalize we get the eigenvalues of + + + align:start position:0% +we diagonalize we get the eigenvalues of +the gf matrix and + + align:start position:0% +the gf matrix and + + + align:start position:0% +the gf matrix and +we also get the l matrix and the l + + align:start position:0% +we also get the l matrix and the l + + + align:start position:0% +we also get the l matrix and the l +matrix is a bunch of numbers + + align:start position:0% +matrix is a bunch of numbers + + + align:start position:0% +matrix is a bunch of numbers +and + + align:start position:0% +and + + + align:start position:0% +and +in order to + + align:start position:0% +in order to + + + align:start position:0% +in order to +go from + + align:start position:0% + + + + align:start position:0% + +the simple things + + align:start position:0% +the simple things + + + align:start position:0% +the simple things +the internal displacements to the things + + align:start position:0% +the internal displacements to the things + + + align:start position:0% +the internal displacements to the things +we want the normal displacements + + align:start position:0% +we want the normal displacements + + + align:start position:0% +we want the normal displacements +we need the inverse l matrix and there's + + align:start position:0% +we need the inverse l matrix and there's + + + align:start position:0% +we need the inverse l matrix and there's +two ways of getting that one is you have + + align:start position:0% +two ways of getting that one is you have + + + align:start position:0% +two ways of getting that one is you have +a numerically defined matrix you can + + align:start position:0% +a numerically defined matrix you can + + + align:start position:0% +a numerically defined matrix you can +tell the computer + + align:start position:0% +tell the computer + + + align:start position:0% +tell the computer +symbolically because it knows linear + + align:start position:0% +symbolically because it knows linear + + + align:start position:0% +symbolically because it knows linear +algebra better than you do how to find + + align:start position:0% +algebra better than you do how to find + + + align:start position:0% +algebra better than you do how to find +the the inverse matrix + + align:start position:0% +the the inverse matrix + + + align:start position:0% +the the inverse matrix +there is also another relationship that + + align:start position:0% +there is also another relationship that + + + align:start position:0% +there is also another relationship that +came + + align:start position:0% +came + + + align:start position:0% +came +as when we were dealing with the uh + + align:start position:0% +as when we were dealing with the uh + + + align:start position:0% +as when we were dealing with the uh +analysis of the vibrational problem we + + align:start position:0% + + + + align:start position:0% + +saw that this + + align:start position:0% +saw that this + + + align:start position:0% +saw that this +had to be true + + align:start position:0% +had to be true + + + align:start position:0% +had to be true +the + + align:start position:0% +the + + + align:start position:0% +the +l matrix + + align:start position:0% +l matrix + + + align:start position:0% +l matrix +multiplied b inverse of the g matrix + + align:start position:0% +multiplied b inverse of the g matrix + + + align:start position:0% +multiplied b inverse of the g matrix +multiplied by the conjugate transpose of + + align:start position:0% +multiplied by the conjugate transpose of + + + align:start position:0% +multiplied by the conjugate transpose of +the l matrix and since these matrices + + align:start position:0% +the l matrix and since these matrices + + + align:start position:0% +the l matrix and since these matrices +are real conjugate transpose is just + + align:start position:0% +are real conjugate transpose is just + + + align:start position:0% +are real conjugate transpose is just +transpose + + align:start position:0% +transpose + + + align:start position:0% +transpose +we could get the inverse + + align:start position:0% + + + + align:start position:0% + +yeah that's right we could get the uh + + align:start position:0% + + + + align:start position:0% + +inverse l matrix simply by multiplying + + align:start position:0% +inverse l matrix simply by multiplying + + + align:start position:0% +inverse l matrix simply by multiplying +this on the left on the right by the + + align:start position:0% +this on the left on the right by the + + + align:start position:0% +this on the left on the right by the +inverse so we have l dagger g minus 1 l + + align:start position:0% +inverse so we have l dagger g minus 1 l + + + align:start position:0% +inverse so we have l dagger g minus 1 l +l minus 1. + + align:start position:0% +l minus 1. + + + align:start position:0% +l minus 1. +so + + align:start position:0% +so + + + align:start position:0% +so +symbolically the inverse l matrix is + + align:start position:0% +symbolically the inverse l matrix is + + + align:start position:0% +symbolically the inverse l matrix is +just l dagger which you know + + align:start position:0% +just l dagger which you know + + + align:start position:0% +just l dagger which you know +and g inverse which you don't know you + + align:start position:0% +and g inverse which you don't know you + + + align:start position:0% +and g inverse which you don't know you +have to invert g + + align:start position:0% +have to invert g + + + align:start position:0% +have to invert g +so some matrix is going to have to be + + align:start position:0% +so some matrix is going to have to be + + + align:start position:0% +so some matrix is going to have to be +inverted + + align:start position:0% +inverted + + + align:start position:0% +inverted +either allergy + + align:start position:0% +either allergy + + + align:start position:0% +either allergy +doesn't matter + + align:start position:0% + + + + align:start position:0% + +okay so + + align:start position:0% +okay so + + + align:start position:0% +okay so +once you now have the eigenvectors once + + align:start position:0% +once you now have the eigenvectors once + + + align:start position:0% +once you now have the eigenvectors once +you have + + align:start position:0% +you have + + + align:start position:0% +you have +uh this l major this l inverse matrix + + align:start position:0% +uh this l major this l inverse matrix + + + align:start position:0% +uh this l major this l inverse matrix +you can write what each of the normal + + align:start position:0% +you can write what each of the normal + + + align:start position:0% +you can write what each of the normal +modes + + align:start position:0% +modes + + + align:start position:0% +modes +is in terms of the internal + + align:start position:0% +is in terms of the internal + + + align:start position:0% +is in terms of the internal +displacements + + align:start position:0% +displacements + + + align:start position:0% +displacements +and + + align:start position:0% +and + + + align:start position:0% +and +when you do that + + align:start position:0% +when you do that + + + align:start position:0% +when you do that +you can begin to draw pictures of what + + align:start position:0% +you can begin to draw pictures of what + + + align:start position:0% +you can begin to draw pictures of what +the + + align:start position:0% +the + + + align:start position:0% +the +motions of the individual atoms in the + + align:start position:0% +motions of the individual atoms in the + + + align:start position:0% +motions of the individual atoms in the +molecule look like + + align:start position:0% +molecule look like + + + align:start position:0% +molecule look like +and from those pictures you can + + align:start position:0% +and from those pictures you can + + + align:start position:0% +and from those pictures you can +say what the + + align:start position:0% +say what the + + + align:start position:0% +say what the +name of the mode is symmetric stretch + + align:start position:0% +name of the mode is symmetric stretch + + + align:start position:0% +name of the mode is symmetric stretch +and asymmetric stretch bend simply by + + align:start position:0% +and asymmetric stretch bend simply by + + + align:start position:0% +and asymmetric stretch bend simply by +seeing how these vectors + + align:start position:0% +seeing how these vectors + + + align:start position:0% +seeing how these vectors +look + + align:start position:0% +look + + + align:start position:0% +look +and so uh + + align:start position:0% +and so uh + + + align:start position:0% +and so uh +the l inverse matrix tells you how to + + align:start position:0% +the l inverse matrix tells you how to + + + align:start position:0% +the l inverse matrix tells you how to +build this out of the + + align:start position:0% +build this out of the + + + align:start position:0% +build this out of the +uh internal displacements and then you + + align:start position:0% +uh internal displacements and then you + + + align:start position:0% +uh internal displacements and then you +just draw vectors + + align:start position:0% +just draw vectors + + + align:start position:0% +just draw vectors +uh + + align:start position:0% +uh + + + align:start position:0% +uh +of + + align:start position:0% +of + + + align:start position:0% +of +uh in the appropriate directions and + + align:start position:0% +uh in the appropriate directions and + + + align:start position:0% +uh in the appropriate directions and +lengths + + align:start position:0% +lengths + + + align:start position:0% +lengths +and you can see what the + + align:start position:0% +and you can see what the + + + align:start position:0% +and you can see what the +matrices look like now on page five of + + align:start position:0% +matrices look like now on page five of + + + align:start position:0% +matrices look like now on page five of +the notes uh + + align:start position:0% +the notes uh + + + align:start position:0% +the notes uh +q1 and q2 the co + + align:start position:0% +q1 and q2 the co + + + align:start position:0% +q1 and q2 the co +the indices are reversed + + align:start position:0% + + + + align:start position:0% + +because these are + + align:start position:0% +because these are + + + align:start position:0% +because these are +this is a combination of notes written + + align:start position:0% +this is a combination of notes written + + + align:start position:0% +this is a combination of notes written +years apart and + + align:start position:0% +years apart and + + + align:start position:0% +years apart and +i discovered only after combining them + + align:start position:0% +i discovered only after combining them + + + align:start position:0% +i discovered only after combining them +that i used a different convention okay + + align:start position:0% +that i used a different convention okay + + + align:start position:0% +that i used a different convention okay +so + + align:start position:0% + + + + align:start position:0% + +by looking at + + align:start position:0% +by looking at + + + align:start position:0% +by looking at +the eigenvectors you can just say that + + align:start position:0% +the eigenvectors you can just say that + + + align:start position:0% +the eigenvectors you can just say that +q1 + + align:start position:0% +q1 + + + align:start position:0% +q1 +the the one with the frequency of 38 + + align:start position:0% +the the one with the frequency of 38 + + + align:start position:0% +the the one with the frequency of 38 + + align:start position:0% + + + align:start position:0% +is a symmetric + + align:start position:0% +is a symmetric + + + align:start position:0% +is a symmetric +stretch + + align:start position:0% +stretch + + + align:start position:0% +stretch +because + + align:start position:0% +because + + + align:start position:0% +because +the two identical bonds + + align:start position:0% +the two identical bonds + + + align:start position:0% +the two identical bonds +are oscillating in phase + + align:start position:0% +are oscillating in phase + + + align:start position:0% +are oscillating in phase +and they're oscillating by the same + + align:start position:0% +and they're oscillating by the same + + + align:start position:0% +and they're oscillating by the same +amount + + align:start position:0% +amount + + + align:start position:0% +amount +and we can call this thing + + align:start position:0% +and we can call this thing + + + align:start position:0% +and we can call this thing +the one with + + align:start position:0% + + + + align:start position:0% + +39 42 + + align:start position:0% +39 42 + + + align:start position:0% +39 42 +the anti-symmetric + + align:start position:0% + + + + align:start position:0% + +stretch + + align:start position:0% +stretch + + + align:start position:0% +stretch +now i have a little bit of a + + align:start position:0% +now i have a little bit of a + + + align:start position:0% +now i have a little bit of a +anal compulsive streak in me that when + + align:start position:0% +anal compulsive streak in me that when + + + align:start position:0% +anal compulsive streak in me that when +you have two + + align:start position:0% +you have two + + + align:start position:0% +you have two +uh identical bonds + + align:start position:0% +uh identical bonds + + + align:start position:0% +uh identical bonds +there are symmetric and antisymmetric + + align:start position:0% +there are symmetric and antisymmetric + + + align:start position:0% +there are symmetric and antisymmetric +stretches + + align:start position:0% +stretches + + + align:start position:0% +stretches +from other cases it's okay to talk about + + align:start position:0% +from other cases it's okay to talk about + + + align:start position:0% +from other cases it's okay to talk about +asymmetric stretches but when there's + + align:start position:0% +asymmetric stretches but when there's + + + align:start position:0% +asymmetric stretches but when there's +two + + align:start position:0% +two + + + align:start position:0% +two +and you can have them symmetra you can + + align:start position:0% +and you can have them symmetra you can + + + align:start position:0% +and you can have them symmetra you can +have them with the same phase or + + align:start position:0% +have them with the same phase or + + + align:start position:0% +have them with the same phase or +opposite phase it's symmetric and + + align:start position:0% +opposite phase it's symmetric and + + + align:start position:0% +opposite phase it's symmetric and +antisymmetric + + align:start position:0% +antisymmetric + + + align:start position:0% +antisymmetric +and i'm sure that you'll have a laugh + + align:start position:0% +and i'm sure that you'll have a laugh + + + align:start position:0% +and i'm sure that you'll have a laugh +about that and then this other one the + + align:start position:0% +about that and then this other one the + + + align:start position:0% +about that and then this other one the +low frequency guy is the bend + + align:start position:0% +low frequency guy is the bend + + + align:start position:0% +low frequency guy is the bend +and the vectors tell you all about that + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +now + + align:start position:0% + + + + align:start position:0% + +in describing + + align:start position:0% +in describing + + + align:start position:0% +in describing +the various + + align:start position:0% +the various + + + align:start position:0% +the various +normal modes + + align:start position:0% +normal modes + + + align:start position:0% +normal modes +uh + + align:start position:0% +uh + + + align:start position:0% +uh +q1 + + align:start position:0% +q1 + + + align:start position:0% +q1 +is written as minus o6a + + align:start position:0% + + + + align:start position:0% + +s1 + + align:start position:0% +s1 + + + align:start position:0% +s1 +plus + + align:start position:0% +plus + + + align:start position:0% +plus +0.685 + + align:start position:0% +0.685 + + + align:start position:0% +0.685 +s2 + + align:start position:0% +s2 + + + align:start position:0% +s2 +two internal stretches + + align:start position:0% +two internal stretches + + + align:start position:0% +two internal stretches +and q2 + + align:start position:0% +and q2 + + + align:start position:0% +and q2 +is written as + + align:start position:0% +is written as + + + align:start position:0% +is written as +0.695 + + align:start position:0% + + + + align:start position:0% + +s1 + + align:start position:0% +s1 + + + align:start position:0% +s1 +plus + + align:start position:0% +plus + + + align:start position:0% +plus +0.695 + + align:start position:0% + + + + align:start position:0% + +s2 + + align:start position:0% +s2 + + + align:start position:0% +s2 +plus 0.037 + + align:start position:0% + + + + align:start position:0% + +s3 + + align:start position:0% +s3 + + + align:start position:0% +s3 +notice we have two equal numbers + + align:start position:0% +notice we have two equal numbers + + + align:start position:0% +notice we have two equal numbers +of opposite signs here we have two + + align:start position:0% +of opposite signs here we have two + + + align:start position:0% +of opposite signs here we have two +equal numbers of the same sign and a + + align:start position:0% +equal numbers of the same sign and a + + + align:start position:0% +equal numbers of the same sign and a +little bit of this bet so these are two + + align:start position:0% +little bit of this bet so these are two + + + align:start position:0% +little bit of this bet so these are two +stretches in out of phase and in phase + + align:start position:0% +stretches in out of phase and in phase + + + align:start position:0% +stretches in out of phase and in phase +and a straight and a bend + + align:start position:0% +and a straight and a bend + + + align:start position:0% +and a straight and a bend +and + + align:start position:0% +and + + + align:start position:0% +and +uh q3 + + align:start position:0% +uh q3 + + + align:start position:0% +uh q3 +is just oh 6 5 5 + + align:start position:0% +is just oh 6 5 5 + + + align:start position:0% +is just oh 6 5 5 +s3 + + align:start position:0% +s3 + + + align:start position:0% +s3 +so the three normal modes + + align:start position:0% +so the three normal modes + + + align:start position:0% +so the three normal modes +have this form + + align:start position:0% +have this form + + + align:start position:0% +have this form +notice there's no s3 + + align:start position:0% +notice there's no s3 + + + align:start position:0% +notice there's no s3 +in + + align:start position:0% +in + + + align:start position:0% +in +q1 + + align:start position:0% +q1 + + + align:start position:0% +q1 +there's s3 and these two + + align:start position:0% + + + + align:start position:0% + +s3 is the bend + + align:start position:0% +s3 is the bend + + + align:start position:0% +s3 is the bend +and somehow this guy + + align:start position:0% +and somehow this guy + + + align:start position:0% +and somehow this guy +doesn't have now + + align:start position:0% +doesn't have now + + + align:start position:0% +doesn't have now +this these numbers come out equal + + align:start position:0% +this these numbers come out equal + + + align:start position:0% +this these numbers come out equal +because + + align:start position:0% +because + + + align:start position:0% +because +uh the eigenvectors of a matrix said + + align:start position:0% +uh the eigenvectors of a matrix said + + + align:start position:0% +uh the eigenvectors of a matrix said +they're equal we're not imposing any + + align:start position:0% +they're equal we're not imposing any + + + align:start position:0% +they're equal we're not imposing any +symmetry these numbers came out equal + + align:start position:0% +symmetry these numbers came out equal + + + align:start position:0% +symmetry these numbers came out equal +and opposite these numbers came out to + + align:start position:0% +and opposite these numbers came out to + + + align:start position:0% +and opposite these numbers came out to +be the same + + align:start position:0% +be the same + + + align:start position:0% +be the same +again because of the structure of the + + align:start position:0% +again because of the structure of the + + + align:start position:0% +again because of the structure of the +matrix these two numbers + + align:start position:0% +matrix these two numbers + + + align:start position:0% +matrix these two numbers +are very different and different in + + align:start position:0% +are very different and different in + + + align:start position:0% +are very different and different in +magnitude this guy + + align:start position:0% +magnitude this guy + + + align:start position:0% +magnitude this guy +uh is predominantly a bend it has a + + align:start position:0% +uh is predominantly a bend it has a + + + align:start position:0% +uh is predominantly a bend it has a +little bit + + align:start position:0% +little bit + + + align:start position:0% +little bit +uh whoops + + align:start position:0% +uh whoops + + + align:start position:0% +uh whoops +um i'm sorry + + align:start position:0% +um i'm sorry + + + align:start position:0% +um i'm sorry +this guy is + + align:start position:0% +this guy is + + + align:start position:0% +this guy is +basically a pure bend this is + + align:start position:0% +basically a pure bend this is + + + align:start position:0% +basically a pure bend this is +predominantly a symmetric stretch and + + align:start position:0% +predominantly a symmetric stretch and + + + align:start position:0% +predominantly a symmetric stretch and +has a little bit of uh bend in it + + align:start position:0% +has a little bit of uh bend in it + + + align:start position:0% +has a little bit of uh bend in it +why just a little bit + + align:start position:0% +why just a little bit + + + align:start position:0% +why just a little bit +how do the g and f matrices tell us + + align:start position:0% +how do the g and f matrices tell us + + + align:start position:0% +how do the g and f matrices tell us +about the mixing of the internal + + align:start position:0% +about the mixing of the internal + + + align:start position:0% +about the mixing of the internal +coordinates + + align:start position:0% +coordinates + + + align:start position:0% +coordinates +so you look at these and you see oh yeah + + align:start position:0% +so you look at these and you see oh yeah + + + align:start position:0% +so you look at these and you see oh yeah +it's obviously antisymmetric symmetric + + align:start position:0% +it's obviously antisymmetric symmetric + + + align:start position:0% +it's obviously antisymmetric symmetric +and this is obviously + + align:start position:0% +and this is obviously + + + align:start position:0% +and this is obviously +a bend and this is a stretch with a + + align:start position:0% +a bend and this is a stretch with a + + + align:start position:0% +a bend and this is a stretch with a +little bit of bend in it + + align:start position:0% + + + + align:start position:0% + +okay so what do we do + + align:start position:0% + + + + align:start position:0% + +what are the rules that you use for + + align:start position:0% +what are the rules that you use for + + + align:start position:0% +what are the rules that you use for +normalization + + align:start position:0% +normalization + + + align:start position:0% +normalization +there's no normalization + + align:start position:0% +there's no normalization + + + align:start position:0% +there's no normalization +okay + + align:start position:0% +okay + + + align:start position:0% +okay +i mean you started with normalized + + align:start position:0% +i mean you started with normalized + + + align:start position:0% +i mean you started with normalized +quantities + + align:start position:0% +quantities + + + align:start position:0% +quantities +somewhere over here + + align:start position:0% + + + + align:start position:0% + +the little stl + + align:start position:0% +the little stl + + + align:start position:0% +the little stl +that's right + + align:start position:0% +that's right + + + align:start position:0% +that's right +and so you're building you start with + + align:start position:0% +and so you're building you start with + + + align:start position:0% +and so you're building you start with +normal you know the you start with unit + + align:start position:0% +normal you know the you start with unit + + + align:start position:0% +normal you know the you start with unit +vectors + + align:start position:0% +vectors + + + align:start position:0% +vectors +and so everything then is normalized in + + align:start position:0% +and so everything then is normalized in + + + align:start position:0% +and so everything then is normalized in +that sense + + align:start position:0% +that sense + + + align:start position:0% +that sense +so you're mixing these st alphas + + align:start position:0% +so you're mixing these st alphas + + + align:start position:0% +so you're mixing these st alphas +and all this is just several steps of + + align:start position:0% +and all this is just several steps of + + + align:start position:0% +and all this is just several steps of +transformations of the st alphas so + + align:start position:0% +transformations of the st alphas so + + + align:start position:0% +transformations of the st alphas so +these + + align:start position:0% +these + + + align:start position:0% +these +uh there's no normalization at all + + align:start position:0% +uh there's no normalization at all + + + align:start position:0% +uh there's no normalization at all +i've often thought about that what do + + align:start position:0% +i've often thought about that what do + + + align:start position:0% +i've often thought about that what do +these numbers mean + + align:start position:0% +these numbers mean + + + align:start position:0% +these numbers mean +is there some + + align:start position:0% +is there some + + + align:start position:0% +is there some +you know it's so close to + + align:start position:0% +you know it's so close to + + + align:start position:0% +you know it's so close to +this is very close to one over the + + align:start position:0% +this is very close to one over the + + + align:start position:0% +this is very close to one over the +square root of two but it's not and this + + align:start position:0% +square root of two but it's not and this + + + align:start position:0% +square root of two but it's not and this +is also very close to one over n squared + + align:start position:0% +is also very close to one over n squared + + + align:start position:0% +is also very close to one over n squared +it's closer but it's not and you know + + align:start position:0% +it's closer but it's not and you know + + + align:start position:0% +it's closer but it's not and you know +and this one is just an orphan + + align:start position:0% + + + + align:start position:0% + +and you would expect in fact i'm a + + align:start position:0% +and you would expect in fact i'm a + + + align:start position:0% +and you would expect in fact i'm a +little puzzled at whether there should + + align:start position:0% +little puzzled at whether there should + + + align:start position:0% +little puzzled at whether there should +have been some more stuff here or not + + align:start position:0% +have been some more stuff here or not + + + align:start position:0% +have been some more stuff here or not +but + + align:start position:0% +but + + + align:start position:0% +but +anyway + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +it is reasonable to ask + + align:start position:0% +it is reasonable to ask + + + align:start position:0% +it is reasonable to ask +can we + + align:start position:0% +can we + + + align:start position:0% +can we +by looking at the f and g + + align:start position:0% +by looking at the f and g + + + align:start position:0% +by looking at the f and g +oh i'm getting ahead of myself can we by + + align:start position:0% +oh i'm getting ahead of myself can we by + + + align:start position:0% +oh i'm getting ahead of myself can we by +looking at the f and g matrices + + align:start position:0% +looking at the f and g matrices + + + align:start position:0% +looking at the f and g matrices +understand + + align:start position:0% +understand + + + align:start position:0% +understand +the specific or at least the qualitative + + align:start position:0% +the specific or at least the qualitative + + + align:start position:0% +the specific or at least the qualitative +things that determine how much + + align:start position:0% +things that determine how much + + + align:start position:0% +things that determine how much +stretch + + align:start position:0% +stretch + + + align:start position:0% +stretch +how much bend is mixed into a + + align:start position:0% +how much bend is mixed into a + + + align:start position:0% +how much bend is mixed into a +predominantly stretch + + align:start position:0% +predominantly stretch + + + align:start position:0% +predominantly stretch +when you have normal modes + + align:start position:0% +when you have normal modes + + + align:start position:0% +when you have normal modes +of the same symmetry + + align:start position:0% +of the same symmetry + + + align:start position:0% +of the same symmetry +they are going to be mixtures of the + + align:start position:0% +they are going to be mixtures of the + + + align:start position:0% +they are going to be mixtures of the +of combinations of internal coordinates + + align:start position:0% +of combinations of internal coordinates + + + align:start position:0% +of combinations of internal coordinates +of similar of the same symmetry but what + + align:start position:0% +of similar of the same symmetry but what + + + align:start position:0% +of similar of the same symmetry but what +is the + + align:start position:0% +is the + + + align:start position:0% +is the +detail of that mixing can you by looking + + align:start position:0% +detail of that mixing can you by looking + + + align:start position:0% +detail of that mixing can you by looking +at the f matrix and the g matrix say yes + + align:start position:0% +at the f matrix and the g matrix say yes + + + align:start position:0% +at the f matrix and the g matrix say yes +there ought to be a lot of mixing of + + align:start position:0% +there ought to be a lot of mixing of + + + align:start position:0% +there ought to be a lot of mixing of +bend with stretch or no there shouldn't + + align:start position:0% +bend with stretch or no there shouldn't + + + align:start position:0% +bend with stretch or no there shouldn't +be what are the dynamical factors but i + + align:start position:0% +be what are the dynamical factors but i + + + align:start position:0% +be what are the dynamical factors but i +got ahead of myself and so i'm going to + + align:start position:0% +got ahead of myself and so i'm going to + + + align:start position:0% +got ahead of myself and so i'm going to +take a brief + + align:start position:0% + + + + align:start position:0% + +yeah so if those like q3 that number + + align:start position:0% +yeah so if those like q3 that number + + + align:start position:0% +yeah so if those like q3 that number +seems like anomalously small right does + + align:start position:0% +seems like anomalously small right does + + + align:start position:0% +seems like anomalously small right does +that really tell you that the magnitude + + align:start position:0% +that really tell you that the magnitude + + + align:start position:0% +that really tell you that the magnitude +of the motion + + align:start position:0% +of the motion + + + align:start position:0% +of the motion +if you have + + align:start position:0% +if you have + + + align:start position:0% +if you have +uh like one quantum of band that like + + align:start position:0% +uh like one quantum of band that like + + + align:start position:0% +uh like one quantum of band that like +the atoms don't move as much no i think + + align:start position:0% +the atoms don't move as much no i think + + + align:start position:0% +the atoms don't move as much no i think +it's just that three atoms are moving + + align:start position:0% +it's just that three atoms are moving + + + align:start position:0% +it's just that three atoms are moving +okay + + align:start position:0% +okay + + + align:start position:0% +okay +i think that uh + + align:start position:0% +i think that uh + + + align:start position:0% +i think that uh +that + + align:start position:0% + + + + align:start position:0% + +yeah s3 involves three atoms moving + + align:start position:0% +yeah s3 involves three atoms moving + + + align:start position:0% +yeah s3 involves three atoms moving +whereas s one and two have two atoms + + align:start position:0% +whereas s one and two have two atoms + + + align:start position:0% +whereas s one and two have two atoms +moving okay + + align:start position:0% + + + + align:start position:0% + +you can put big s3 into the little st + + align:start position:0% +you can put big s3 into the little st + + + align:start position:0% +you can put big s3 into the little st +alphas that comprise it and that's right + + align:start position:0% +alphas that comprise it and that's right + + + align:start position:0% +alphas that comprise it and that's right +then you could tell + + align:start position:0% +then you could tell + + + align:start position:0% +then you could tell +yes in fact when you draw these famous + + align:start position:0% +yes in fact when you draw these famous + + + align:start position:0% +yes in fact when you draw these famous +pictures of arrows + + align:start position:0% +pictures of arrows + + + align:start position:0% +pictures of arrows +uh pointing in of definite lengths + + align:start position:0% +uh pointing in of definite lengths + + + align:start position:0% +uh pointing in of definite lengths +and definite directions uh + + align:start position:0% +and definite directions uh + + + align:start position:0% +and definite directions uh +those you know those comes from the st + + align:start position:0% +those you know those comes from the st + + + align:start position:0% +those you know those comes from the st +alphas + + align:start position:0% +alphas + + + align:start position:0% +alphas +and + + align:start position:0% +and + + + align:start position:0% +and +and so you know what they are and that's + + align:start position:0% +and so you know what they are and that's + + + align:start position:0% +and so you know what they are and that's +what the normal modes are said to look + + align:start position:0% +what the normal modes are said to look + + + align:start position:0% +what the normal modes are said to look +like + + align:start position:0% +like + + + align:start position:0% +like +and so those vectors aren't arbitrary + + align:start position:0% +and so those vectors aren't arbitrary + + + align:start position:0% +and so those vectors aren't arbitrary +objects although frequently you draw + + align:start position:0% +objects although frequently you draw + + + align:start position:0% +objects although frequently you draw +them in a symmetry sense as opposed to a + + align:start position:0% +them in a symmetry sense as opposed to a + + + align:start position:0% +them in a symmetry sense as opposed to a +numerical sense but that's always close + + align:start position:0% +numerical sense but that's always close + + + align:start position:0% +numerical sense but that's always close +okay + + align:start position:0% +okay + + + align:start position:0% +okay +suppose + + align:start position:0% +suppose + + + align:start position:0% +suppose +we have + + align:start position:0% +we have + + + align:start position:0% +we have +two or more identical bond lengths or + + align:start position:0% +two or more identical bond lengths or + + + align:start position:0% +two or more identical bond lengths or +two identical + + align:start position:0% +two identical + + + align:start position:0% +two identical +our or more identical + + align:start position:0% +our or more identical + + + align:start position:0% +our or more identical +internal coordinates in a molecule + + align:start position:0% +internal coordinates in a molecule + + + align:start position:0% +internal coordinates in a molecule +in water there's two identical bond + + align:start position:0% +in water there's two identical bond + + + align:start position:0% +in water there's two identical bond +stretches + + align:start position:0% + + + + align:start position:0% + +in other molecules you might have more + + align:start position:0% +in other molecules you might have more + + + align:start position:0% +in other molecules you might have more +than uh + + align:start position:0% +than uh + + + align:start position:0% +than uh +two in benzene you have + + align:start position:0% +two in benzene you have + + + align:start position:0% +two in benzene you have +six identical chs + + align:start position:0% +six identical chs + + + align:start position:0% +six identical chs +but in toluene it's not that you have + + align:start position:0% +but in toluene it's not that you have + + + align:start position:0% +but in toluene it's not that you have +five identical chs of one flavor and + + align:start position:0% +five identical chs of one flavor and + + + align:start position:0% +five identical chs of one flavor and +three of another you have five and they + + align:start position:0% +three of another you have five and they + + + align:start position:0% +three of another you have five and they +come in + + align:start position:0% +come in + + + align:start position:0% +come in +uh or two ortho two pair two meta and + + align:start position:0% +uh or two ortho two pair two meta and + + + align:start position:0% +uh or two ortho two pair two meta and +one para so + + align:start position:0% +one para so + + + align:start position:0% +one para so +uh + + align:start position:0% +uh + + + align:start position:0% +uh +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so you can symmetrize you can build + + align:start position:0% +so you can symmetrize you can build + + + align:start position:0% +so you can symmetrize you can build +linear combinations + + align:start position:0% +linear combinations + + + align:start position:0% +linear combinations +of + + align:start position:0% +of + + + align:start position:0% +of +identical internal coordinates + + align:start position:0% +identical internal coordinates + + + align:start position:0% +identical internal coordinates +for example + + align:start position:0% +for example + + + align:start position:0% +for example +so here is what's called a symmetrized + + align:start position:0% +so here is what's called a symmetrized + + + align:start position:0% +so here is what's called a symmetrized +internal coordinate now people use + + align:start position:0% +internal coordinate now people use + + + align:start position:0% +internal coordinate now people use +different notations because + + align:start position:0% +different notations because + + + align:start position:0% +different notations because +they like to use s + + align:start position:0% +they like to use s + + + align:start position:0% +they like to use s +for symmetrized internal coordinates + + align:start position:0% +for symmetrized internal coordinates + + + align:start position:0% +for symmetrized internal coordinates +but s has been taken + + align:start position:0% +but s has been taken + + + align:start position:0% +but s has been taken +and so what do they do well some people + + align:start position:0% +and so what do they do well some people + + + align:start position:0% +and so what do they do well some people +use s for symmetrized internal + + align:start position:0% +use s for symmetrized internal + + + align:start position:0% +use s for symmetrized internal +coordinates and then they pretend that + + align:start position:0% +coordinates and then they pretend that + + + align:start position:0% +coordinates and then they pretend that +the it hasn't so you have some matrix + + align:start position:0% +the it hasn't so you have some matrix + + + align:start position:0% +the it hasn't so you have some matrix +that combines the individual + + align:start position:0% +that combines the individual + + + align:start position:0% +that combines the individual +non-symmetrized internal coordinates + + align:start position:0% +non-symmetrized internal coordinates + + + align:start position:0% +non-symmetrized internal coordinates +and so if in the case of water this + + align:start position:0% +and so if in the case of water this + + + align:start position:0% +and so if in the case of water this +matrix would have the form + + align:start position:0% +matrix would have the form + + + align:start position:0% +matrix would have the form +1 over square root of 2 + + align:start position:0% + + + + align:start position:0% + +1 over square root of 2 + + align:start position:0% + + + + align:start position:0% + + + align:start position:0% + + + + align:start position:0% + +over square root of 2 + + align:start position:0% +over square root of 2 + + + align:start position:0% +over square root of 2 +minus 1 over square root of two + + align:start position:0% +minus 1 over square root of two + + + align:start position:0% +minus 1 over square root of two +zero zero zero one + + align:start position:0% +zero zero zero one + + + align:start position:0% +zero zero zero one +i mean it's really easy if there's only + + align:start position:0% +i mean it's really easy if there's only + + + align:start position:0% +i mean it's really easy if there's only +two objects you you + + align:start position:0% +two objects you you + + + align:start position:0% +two objects you you +uh + + align:start position:0% +uh + + + align:start position:0% +uh +you just have a normalized thing and + + align:start position:0% +you just have a normalized thing and + + + align:start position:0% +you just have a normalized thing and +then + + align:start position:0% +then + + + align:start position:0% +then +that's easy so + + align:start position:0% +that's easy so + + + align:start position:0% +that's easy so +we define the symmetrized uh + + align:start position:0% +we define the symmetrized uh + + + align:start position:0% +we define the symmetrized uh +uh + + align:start position:0% +uh + + + align:start position:0% +uh +coordinates by + + align:start position:0% +coordinates by + + + align:start position:0% +coordinates by +uh applying this transformation to the + + align:start position:0% +uh applying this transformation to the + + + align:start position:0% +uh applying this transformation to the +non-symmetrized things the f matrix + + align:start position:0% +non-symmetrized things the f matrix + + + align:start position:0% +non-symmetrized things the f matrix +elements are given by this + + align:start position:0% +elements are given by this + + + align:start position:0% +elements are given by this +so these are the non-symmetrized things + + align:start position:0% +so these are the non-symmetrized things + + + align:start position:0% +so these are the non-symmetrized things +this is the + + align:start position:0% +this is the + + + align:start position:0% +this is the +okay and now we can + + align:start position:0% +okay and now we can + + + align:start position:0% +okay and now we can +insert + + align:start position:0% +insert + + + align:start position:0% +insert +one + + align:start position:0% +one + + + align:start position:0% +one +this is a unitary matrix as opposed to + + align:start position:0% +this is a unitary matrix as opposed to + + + align:start position:0% +this is a unitary matrix as opposed to +just a + + align:start position:0% +just a + + + align:start position:0% +just a +matrix it's a + + align:start position:0% +matrix it's a + + + align:start position:0% +matrix it's a +normalization preserving matrix we can + + align:start position:0% +normalization preserving matrix we can + + + align:start position:0% +normalization preserving matrix we can +rewrite this as + + align:start position:0% +rewrite this as + + + align:start position:0% +rewrite this as +u dagger u + + align:start position:0% +u dagger u + + + align:start position:0% +u dagger u +uh f + + align:start position:0% +uh f + + + align:start position:0% +uh f +u dagger + + align:start position:0% +u dagger + + + align:start position:0% +u dagger +u + + align:start position:0% +u + + + align:start position:0% +u +s + + align:start position:0% +s + + + align:start position:0% +s +we've just inserted one + + align:start position:0% +we've just inserted one + + + align:start position:0% +we've just inserted one +into this formula twice + + align:start position:0% + + + + align:start position:0% + +and i did it right + + align:start position:0% +and i did it right + + + align:start position:0% +and i did it right +and + + align:start position:0% +and + + + align:start position:0% +and +so we can then rewrite this and say s + + align:start position:0% +so we can then rewrite this and say s + + + align:start position:0% +so we can then rewrite this and say s +twiddle f + + align:start position:0% +twiddle f + + + align:start position:0% +twiddle f +twiddle + + align:start position:0% +twiddle + + + align:start position:0% +twiddle +s twiddle + + align:start position:0% +s twiddle + + + align:start position:0% +s twiddle +this transformation takes this + + align:start position:0% +this transformation takes this + + + align:start position:0% +this transformation takes this +to this and so this is the symmetrized + + align:start position:0% +to this and so this is the symmetrized + + + align:start position:0% +to this and so this is the symmetrized +force constant matrix and these are the + + align:start position:0% +force constant matrix and these are the + + + align:start position:0% +force constant matrix and these are the +symmetrized functions + + align:start position:0% +symmetrized functions + + + align:start position:0% +symmetrized functions +in that representation + + align:start position:0% +in that representation + + + align:start position:0% +in that representation +what we find + + align:start position:0% +what we find + + + align:start position:0% +what we find +is that + + align:start position:0% +is that + + + align:start position:0% +is that +the force constant matrix is block + + align:start position:0% +the force constant matrix is block + + + align:start position:0% +the force constant matrix is block +diagonalized + + align:start position:0% + + + + align:start position:0% + +and it's block diagonalized in the + + align:start position:0% + + + + align:start position:0% + +in the representation i've been using + + align:start position:0% +in the representation i've been using + + + align:start position:0% +in the representation i've been using +it's block diagonalized in the sense + + align:start position:0% +it's block diagonalized in the sense + + + align:start position:0% +it's block diagonalized in the sense +where we have zero here here here and + + align:start position:0% +where we have zero here here here and + + + align:start position:0% +where we have zero here here here and +here + + align:start position:0% +here + + + align:start position:0% +here +uh + + align:start position:0% +uh + + + align:start position:0% +uh +and uh + + align:start position:0% +and uh + + + align:start position:0% +and uh +and + + align:start position:0% +and + + + align:start position:0% +and +numbers + + align:start position:0% +numbers + + + align:start position:0% +numbers +here and here and that's awkward and so + + align:start position:0% +here and here and that's awkward and so + + + align:start position:0% +here and here and that's awkward and so +you simply rearrange rows and columns + + align:start position:0% +you simply rearrange rows and columns + + + align:start position:0% +you simply rearrange rows and columns +and you end up having + + align:start position:0% +and you end up having + + + align:start position:0% +and you end up having +the + + align:start position:0% + + + + align:start position:0% + +force constant matrix + + align:start position:0% +force constant matrix + + + align:start position:0% +force constant matrix +with numbers + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +it becomes a symmetric matrix + + align:start position:0% +it becomes a symmetric matrix + + + align:start position:0% +it becomes a symmetric matrix +there's a two by two symmetric matrix + + align:start position:0% +there's a two by two symmetric matrix + + + align:start position:0% +there's a two by two symmetric matrix +and a one by one + + align:start position:0% +and a one by one + + + align:start position:0% +and a one by one +it has block diagonalized so + + align:start position:0% +it has block diagonalized so + + + align:start position:0% +it has block diagonalized so +this transformation + + align:start position:0% +this transformation + + + align:start position:0% +this transformation +where all you do is you say i have two + + align:start position:0% +where all you do is you say i have two + + + align:start position:0% +where all you do is you say i have two +identical internal displacements i don't + + align:start position:0% +identical internal displacements i don't + + + align:start position:0% +identical internal displacements i don't +know about group theory + + align:start position:0% + + + + align:start position:0% + +it has transformed this three by three + + align:start position:0% +it has transformed this three by three + + + align:start position:0% +it has transformed this three by three +matrix into a two by two and a one by + + align:start position:0% +matrix into a two by two and a one by + + + align:start position:0% +matrix into a two by two and a one by +one + + align:start position:0% + + + + align:start position:0% + +and amazingly it does the same thing to + + align:start position:0% +and amazingly it does the same thing to + + + align:start position:0% +and amazingly it does the same thing to +the g matrix + + align:start position:0% + + + + align:start position:0% + +and so + + align:start position:0% +and so + + + align:start position:0% +and so +you can + + align:start position:0% +you can + + + align:start position:0% +you can +uh factor + + align:start position:0% +uh factor + + + align:start position:0% +uh factor +the f matrix and the g matrix both into + + align:start position:0% +the f matrix and the g matrix both into + + + align:start position:0% +the f matrix and the g matrix both into +two by twos and one by ones and when you + + align:start position:0% +two by twos and one by ones and when you + + + align:start position:0% +two by twos and one by ones and when you +do that the gf matrix is also of this + + align:start position:0% + + + + align:start position:0% + +form + + align:start position:0% +form + + + align:start position:0% +form +where you have a two by two and a one by + + align:start position:0% +where you have a two by two and a one by + + + align:start position:0% +where you have a two by two and a one by +one + + align:start position:0% +one + + + align:start position:0% +one +and this + + align:start position:0% +and this + + + align:start position:0% +and this +is the this block is associated with the + + align:start position:0% +is the this block is associated with the + + + align:start position:0% +is the this block is associated with the +totally symmetric levels + + align:start position:0% +totally symmetric levels + + + align:start position:0% +totally symmetric levels +the bend and the symmetric stretch and + + align:start position:0% +the bend and the symmetric stretch and + + + align:start position:0% +the bend and the symmetric stretch and +this block is associated with the + + align:start position:0% +this block is associated with the + + + align:start position:0% +this block is associated with the +antisymmetric level + + align:start position:0% + + + + align:start position:0% + +okay so now + + align:start position:0% + + + + align:start position:0% + +we've discovered that no + + align:start position:0% +we've discovered that no + + + align:start position:0% +we've discovered that no +even though you don't start out by using + + align:start position:0% +even though you don't start out by using + + + align:start position:0% +even though you don't start out by using +group theory + + align:start position:0% +group theory + + + align:start position:0% +group theory +you can + + align:start position:0% +you can + + + align:start position:0% +you can +factor this problem in uh into + + align:start position:0% +factor this problem in uh into + + + align:start position:0% +factor this problem in uh into +the simpler + + align:start position:0% +the simpler + + + align:start position:0% +the simpler +units and that's wonderful + + align:start position:0% + + + + align:start position:0% + +and does geez quickly up quickly + + align:start position:0% +and does geez quickly up quickly + + + align:start position:0% +and does geez quickly up quickly +diagonalize to give you an else quickly + + align:start position:0% +diagonalize to give you an else quickly + + + align:start position:0% +diagonalize to give you an else quickly +yes i believe so + + align:start position:0% + + + + align:start position:0% + +okay so + + align:start position:0% +okay so + + + align:start position:0% +okay so +now + + align:start position:0% + + + + align:start position:0% + +what + + align:start position:0% +what + + + align:start position:0% +what +actually can can one look at i mean when + + align:start position:0% +actually can can one look at i mean when + + + align:start position:0% +actually can can one look at i mean when +you have a hamiltonian you can look at + + align:start position:0% +you have a hamiltonian you can look at + + + align:start position:0% +you have a hamiltonian you can look at +the make the form of the matrix and you + + align:start position:0% +the make the form of the matrix and you + + + align:start position:0% +the make the form of the matrix and you +could say there are off-diagonal + + align:start position:0% +could say there are off-diagonal + + + align:start position:0% +could say there are off-diagonal +elements that are there are diagonal + + align:start position:0% +elements that are there are diagonal + + + align:start position:0% +elements that are there are diagonal +elements that are very different and + + align:start position:0% +elements that are very different and + + + align:start position:0% +elements that are very different and +there's an off-diagonal element coupling + + align:start position:0% +there's an off-diagonal element coupling + + + align:start position:0% +there's an off-diagonal element coupling +those two diagonal + + align:start position:0% +those two diagonal + + + align:start position:0% +those two diagonal +things which is small compared to the + + align:start position:0% +things which is small compared to the + + + align:start position:0% +things which is small compared to the +difference in the diagonal element and + + align:start position:0% +difference in the diagonal element and + + + align:start position:0% +difference in the diagonal element and +when that happens + + align:start position:0% +when that happens + + + align:start position:0% +when that happens +the off diagonal element has a + + align:start position:0% +the off diagonal element has a + + + align:start position:0% +the off diagonal element has a +negligible effect on the problem + + align:start position:0% +negligible effect on the problem + + + align:start position:0% +negligible effect on the problem +and so one is always interested in + + align:start position:0% +and so one is always interested in + + + align:start position:0% +and so one is always interested in +making a comparison of the off diagonal + + align:start position:0% +making a comparison of the off diagonal + + + align:start position:0% +making a comparison of the off diagonal +element to the difference in diagonal so + + align:start position:0% +element to the difference in diagonal so + + + align:start position:0% +element to the difference in diagonal so +in this case we have g13 twiddle + + align:start position:0% +in this case we have g13 twiddle + + + align:start position:0% +in this case we have g13 twiddle +and we have g11 twiddle minus g33 + + align:start position:0% +and we have g11 twiddle minus g33 + + + align:start position:0% +and we have g11 twiddle minus g33 +twiddle + + align:start position:0% +twiddle + + + align:start position:0% +twiddle +and we'd like to compare them + + align:start position:0% +and we'd like to compare them + + + align:start position:0% +and we'd like to compare them +and we'd also + + align:start position:0% +and we'd also + + + align:start position:0% +and we'd also +we have f13 + + align:start position:0% +we have f13 + + + align:start position:0% +we have f13 +and + + align:start position:0% +and + + + align:start position:0% +and +f11 twiddle minus f33 twiddle + + align:start position:0% +f11 twiddle minus f33 twiddle + + + align:start position:0% +f11 twiddle minus f33 twiddle +and so even though gf is not a symmetric + + align:start position:0% +and so even though gf is not a symmetric + + + align:start position:0% +and so even though gf is not a symmetric +matrix + + align:start position:0% +matrix + + + align:start position:0% +matrix +we can use some of the same ideas we use + + align:start position:0% +we can use some of the same ideas we use + + + align:start position:0% +we can use some of the same ideas we use +for reading symmetric matrices + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% +and + + + align:start position:0% +and +and so i + + align:start position:0% +and so i + + + align:start position:0% +and so i +uh + + align:start position:0% +uh + + + align:start position:0% +uh +the off diagonal elements + + align:start position:0% +the off diagonal elements + + + align:start position:0% +the off diagonal elements +um + + align:start position:0% +um + + + align:start position:0% +um +g one three and g three one + + align:start position:0% +g one three and g three one + + + align:start position:0% +g one three and g three one +yes don't you care about the diagonal + + align:start position:0% +yes don't you care about the diagonal + + + align:start position:0% +yes don't you care about the diagonal +and off diagonal elements of g f not of + + align:start position:0% +and off diagonal elements of g f not of + + + align:start position:0% +and off diagonal elements of g f not of +g and f individually you do but you can + + align:start position:0% +g and f individually you do but you can + + + align:start position:0% +g and f individually you do but you can +you can you can build it up i mean + + align:start position:0% +you can you can build it up i mean + + + align:start position:0% +you can you can build it up i mean +yes you care about gf + + align:start position:0% +yes you care about gf + + + align:start position:0% +yes you care about gf +but if there's big differences here or + + align:start position:0% +but if there's big differences here or + + + align:start position:0% +but if there's big differences here or +here that will + + align:start position:0% +here that will + + + align:start position:0% +here that will +carry over into + + align:start position:0% +carry over into + + + align:start position:0% +carry over into +the big differences in gf + + align:start position:0% +the big differences in gf + + + align:start position:0% +the big differences in gf +and can they cancel out also + + align:start position:0% +and can they cancel out also + + + align:start position:0% +and can they cancel out also +yeah there's lots of problems but what + + align:start position:0% +yeah there's lots of problems but what + + + align:start position:0% +yeah there's lots of problems but what +you want is some qualitative rules + + align:start position:0% +you want is some qualitative rules + + + align:start position:0% +you want is some qualitative rules +for + + align:start position:0% +for + + + align:start position:0% +for +deciding by looking at masses or + + align:start position:0% +deciding by looking at masses or + + + align:start position:0% +deciding by looking at masses or +adjusting masses or designing a molecule + + align:start position:0% +adjusting masses or designing a molecule + + + align:start position:0% +adjusting masses or designing a molecule +to say i want to + + align:start position:0% +to say i want to + + + align:start position:0% +to say i want to +minimize the mixing of two different + + align:start position:0% +minimize the mixing of two different + + + align:start position:0% +minimize the mixing of two different +kinds of internal coordinates + + align:start position:0% +kinds of internal coordinates + + + align:start position:0% +kinds of internal coordinates +how do i do that what + + align:start position:0% +how do i do that what + + + align:start position:0% +how do i do that what +causes that to happen + + align:start position:0% +causes that to happen + + + align:start position:0% +causes that to happen +and + + align:start position:0% +and + + + align:start position:0% +and +you + + align:start position:0% +you + + + align:start position:0% +you +there's + + align:start position:0% +there's + + + align:start position:0% +there's +kinetic energy coupling + + align:start position:0% +kinetic energy coupling + + + align:start position:0% +kinetic energy coupling +uh which is expressed by examining the g + + align:start position:0% +uh which is expressed by examining the g + + + align:start position:0% +uh which is expressed by examining the g +matrix and there's potential energy + + align:start position:0% +matrix and there's potential energy + + + align:start position:0% +matrix and there's potential energy +coupling which is obtained by + + align:start position:0% +coupling which is obtained by + + + align:start position:0% +coupling which is obtained by +uh + + align:start position:0% +uh + + + align:start position:0% +uh +examining the f matrix and so you can + + align:start position:0% +examining the f matrix and so you can + + + align:start position:0% +examining the f matrix and so you can +look at both + + align:start position:0% +look at both + + + align:start position:0% +look at both +and you can draw conclusions so on page + + align:start position:0% +and you can draw conclusions so on page + + + align:start position:0% +and you can draw conclusions so on page +10 of my notes i have a formula + + align:start position:0% +10 of my notes i have a formula + + + align:start position:0% +10 of my notes i have a formula +expressing g13 in terms of a bond length + + align:start position:0% +expressing g13 in terms of a bond length + + + align:start position:0% +expressing g13 in terms of a bond length +and an angle and a mass + + align:start position:0% +and an angle and a mass + + + align:start position:0% +and an angle and a mass +and + + align:start position:0% +and + + + align:start position:0% +and +this is + + align:start position:0% +this is + + + align:start position:0% +this is +this is a fairly famous + + align:start position:0% + + + + align:start position:0% + +brooks pate + + align:start position:0% +brooks pate + + + align:start position:0% +brooks pate +and kevin lehman + + align:start position:0% + + + + align:start position:0% + +idea + + align:start position:0% +idea + + + align:start position:0% +idea +that + + align:start position:0% +that + + + align:start position:0% +that +if you want to + + align:start position:0% +if you want to + + + align:start position:0% +if you want to +minimize coupling + + align:start position:0% +minimize coupling + + + align:start position:0% +minimize coupling +between two + + align:start position:0% +between two + + + align:start position:0% +between two +halves of a molecule if you put a heavy + + align:start position:0% +halves of a molecule if you put a heavy + + + align:start position:0% +halves of a molecule if you put a heavy +atom between them it + + align:start position:0% +atom between them it + + + align:start position:0% +atom between them it +will shut that down and + + align:start position:0% +will shut that down and + + + align:start position:0% +will shut that down and +so + + align:start position:0% +so + + + align:start position:0% +so +in this g13 there is a one over + + align:start position:0% +in this g13 there is a one over + + + align:start position:0% +in this g13 there is a one over +m + + align:start position:0% +m + + + align:start position:0% +m +three which was the center + + align:start position:0% +three which was the center + + + align:start position:0% +three which was the center +atom heavy makes the g13 the coupling + + align:start position:0% +atom heavy makes the g13 the coupling + + + align:start position:0% +atom heavy makes the g13 the coupling +matrix element small + + align:start position:0% +matrix element small + + + align:start position:0% +matrix element small +and so that + + align:start position:0% +and so that + + + align:start position:0% +and so that +shuts down the kinetic energy coupling + + align:start position:0% +shuts down the kinetic energy coupling + + + align:start position:0% +shuts down the kinetic energy coupling +now + + align:start position:0% +now + + + align:start position:0% +now +this difference + + align:start position:0% +this difference + + + align:start position:0% +this difference +would be + + align:start position:0% +would be + + + align:start position:0% +would be +these numbers are small if the + + align:start position:0% +these numbers are small if the + + + align:start position:0% +these numbers are small if the +end atoms are heavy and are large if the + + align:start position:0% +end atoms are heavy and are large if the + + + align:start position:0% +end atoms are heavy and are large if the +end atoms are light + + align:start position:0% +end atoms are light + + + align:start position:0% +end atoms are light +and so + + align:start position:0% + + + + align:start position:0% + +you can look at + + align:start position:0% +you can look at + + + align:start position:0% +you can look at +the structure of the g matrix and you + + align:start position:0% +the structure of the g matrix and you + + + align:start position:0% +the structure of the g matrix and you +can design a molecule either by isotopic + + align:start position:0% +can design a molecule either by isotopic + + + align:start position:0% +can design a molecule either by isotopic +substitution or replacing carbon with + + align:start position:0% +substitution or replacing carbon with + + + align:start position:0% +substitution or replacing carbon with +germanium + + align:start position:0% +germanium + + + align:start position:0% +germanium +that's what they did + + align:start position:0% +that's what they did + + + align:start position:0% +that's what they did +and + + align:start position:0% +and + + + align:start position:0% +and +and you could + + align:start position:0% +and you could + + + align:start position:0% +and you could +try to minimize the communication + + align:start position:0% +try to minimize the communication + + + align:start position:0% +try to minimize the communication +between the different parts of the + + align:start position:0% +between the different parts of the + + + align:start position:0% +between the different parts of the +molecule + + align:start position:0% +molecule + + + align:start position:0% +molecule +and + + align:start position:0% + + + + align:start position:0% + +the this + + align:start position:0% +the this + + + align:start position:0% +the this +the force constant matrix is similar + + align:start position:0% +the force constant matrix is similar + + + align:start position:0% +the force constant matrix is similar +okay one of the things that + + align:start position:0% +okay one of the things that + + + align:start position:0% +okay one of the things that +you discover is force constants + + align:start position:0% +you discover is force constants + + + align:start position:0% +you discover is force constants +for + + align:start position:0% + + + + align:start position:0% + +stretch + + align:start position:0% +stretch + + + align:start position:0% +stretch +stretch force constants + + align:start position:0% +stretch force constants + + + align:start position:0% +stretch force constants +or stretching force constants + + align:start position:0% + + + + align:start position:0% + +are + + align:start position:0% + + + + align:start position:0% + +much larger than + + align:start position:0% +much larger than + + + align:start position:0% +much larger than +bending force constants + + align:start position:0% + + + + align:start position:0% + +and because of that suppose in the case + + align:start position:0% +and because of that suppose in the case + + + align:start position:0% +and because of that suppose in the case +of water you have a symmetric stretch + + align:start position:0% +of water you have a symmetric stretch + + + align:start position:0% +of water you have a symmetric stretch +and a symmetric bend + + align:start position:0% +and a symmetric bend + + + align:start position:0% +and a symmetric bend +they belong to the same symmetry species + + align:start position:0% +they belong to the same symmetry species + + + align:start position:0% +they belong to the same symmetry species +but there's a huge difference between + + align:start position:0% +but there's a huge difference between + + + align:start position:0% +but there's a huge difference between +the force constant for the ben the + + align:start position:0% +the force constant for the ben the + + + align:start position:0% +the force constant for the ben the +stretch and the bend + + align:start position:0% +stretch and the bend + + + align:start position:0% +stretch and the bend +and as a result + + align:start position:0% +and as a result + + + align:start position:0% +and as a result +you have built into the f matrix a big + + align:start position:0% +you have built into the f matrix a big + + + align:start position:0% +you have built into the f matrix a big +difference in diagonal elements that + + align:start position:0% +difference in diagonal elements that + + + align:start position:0% +difference in diagonal elements that +fights this the small coupling between + + align:start position:0% +fights this the small coupling between + + + align:start position:0% +fights this the small coupling between +the stretch and the bend and this is the + + align:start position:0% +the stretch and the bend and this is the + + + align:start position:0% +the stretch and the bend and this is the +the physical basis for the distinction + + align:start position:0% +the physical basis for the distinction + + + align:start position:0% +the physical basis for the distinction +between bending modes and stretching + + align:start position:0% +between bending modes and stretching + + + align:start position:0% +between bending modes and stretching +modes + + align:start position:0% + + + + align:start position:0% + +occasionally you have an irreducible + + align:start position:0% +occasionally you have an irreducible + + + align:start position:0% +occasionally you have an irreducible +representation a symmetry where there's + + align:start position:0% +representation a symmetry where there's + + + align:start position:0% +representation a symmetry where there's +only + + align:start position:0% +only + + + align:start position:0% +only +a stretch or only a bend + + align:start position:0% +a stretch or only a bend + + + align:start position:0% +a stretch or only a bend +for example in formaldehyde + + align:start position:0% +for example in formaldehyde + + + align:start position:0% +for example in formaldehyde +the a2 + + align:start position:0% +the a2 + + + align:start position:0% +the a2 +symmetry is unique for outer plane bend + + align:start position:0% +symmetry is unique for outer plane bend + + + align:start position:0% +symmetry is unique for outer plane bend +and so that's a pure + + align:start position:0% +and so that's a pure + + + align:start position:0% +and so that's a pure +outer plane bend there isn't any stretch + + align:start position:0% +outer plane bend there isn't any stretch + + + align:start position:0% +outer plane bend there isn't any stretch +but there's uh but there are + + align:start position:0% +but there's uh but there are + + + align:start position:0% +but there's uh but there are +often a stretch and a bend or maybe two + + align:start position:0% +often a stretch and a bend or maybe two + + + align:start position:0% +often a stretch and a bend or maybe two +different classes of bends or two + + align:start position:0% +different classes of bends or two + + + align:start position:0% +different classes of bends or two +different classes of stretch and as long + + align:start position:0% +different classes of stretch and as long + + + align:start position:0% +different classes of stretch and as long +as they belong to the same symmetry + + align:start position:0% +as they belong to the same symmetry + + + align:start position:0% +as they belong to the same symmetry +species they'll mix and you can make + + align:start position:0% +species they'll mix and you can make + + + align:start position:0% +species they'll mix and you can make +judgments about what causes the mixing + + align:start position:0% +judgments about what causes the mixing + + + align:start position:0% +judgments about what causes the mixing +based on masses and about these + + align:start position:0% +based on masses and about these + + + align:start position:0% +based on masses and about these +qualitative things and because bending + + align:start position:0% +qualitative things and because bending + + + align:start position:0% +qualitative things and because bending +is it's easier to bend than to stretch + + align:start position:0% +is it's easier to bend than to stretch + + + align:start position:0% +is it's easier to bend than to stretch +there's usually very little bend + + align:start position:0% +there's usually very little bend + + + align:start position:0% +there's usually very little bend +character in stretches + + align:start position:0% +character in stretches + + + align:start position:0% +character in stretches +and you call things stretches and bends + + align:start position:0% +and you call things stretches and bends + + + align:start position:0% +and you call things stretches and bends +what time is it have i talked too long + + align:start position:0% +what time is it have i talked too long + + + align:start position:0% +what time is it have i talked too long +no + + align:start position:0% +no + + + align:start position:0% +no +um okay so + + align:start position:0% + + + + align:start position:0% + +so i haven't gotten to page 11 and 12 + + align:start position:0% +so i haven't gotten to page 11 and 12 + + + align:start position:0% +so i haven't gotten to page 11 and 12 +and i'll probably begin my lecture i + + align:start position:0% +and i'll probably begin my lecture i + + + align:start position:0% +and i'll probably begin my lecture i +mean so there's some + + align:start position:0% +mean so there's some + + + align:start position:0% +mean so there's some +virtue in this because i'm not going to + + align:start position:0% +virtue in this because i'm not going to + + + align:start position:0% +virtue in this because i'm not going to +have any time to prepare for tomorrow + + align:start position:0% +have any time to prepare for tomorrow + + + align:start position:0% +have any time to prepare for tomorrow +morning's lecture so i'll start with + + align:start position:0% +morning's lecture so i'll start with + + + align:start position:0% +morning's lecture so i'll start with +something i really know + + align:start position:0% +something i really know + + + align:start position:0% +something i really know +for tomorrow morning + + align:start position:0% +for tomorrow morning + + + align:start position:0% +for tomorrow morning +okay so that's that's it \ No newline at end of file diff --git a/y1bnBxfNVkU.txt b/y1bnBxfNVkU.txt new file mode 100644 index 0000000000000000000000000000000000000000..5ec882406f93522abf0e5d619fc51a88df5f802f --- /dev/null +++ b/y1bnBxfNVkU.txt @@ -0,0 +1,8984 @@ +align:start position:0% + +So today we're going to continue our + + align:start position:0% +So today we're going to continue our + + + align:start position:0% +So today we're going to continue our +discussion of uh producer Theory + + align:start position:0% +discussion of uh producer Theory + + + align:start position:0% +discussion of uh producer Theory +remember the first few lectures we + + align:start position:0% +remember the first few lectures we + + + align:start position:0% +remember the first few lectures we +developed consumer Theory and where the + + align:start position:0% +developed consumer Theory and where the + + + align:start position:0% +developed consumer Theory and where the +demain curve came from now we're turning + + align:start position:0% +demain curve came from now we're turning + + + align:start position:0% +demain curve came from now we're turning +to producer Theory and where the supply + + align:start position:0% +to producer Theory and where the supply + + + align:start position:0% +to producer Theory and where the supply +curve comes from drawing on a lot of + + align:start position:0% +curve comes from drawing on a lot of + + + align:start position:0% +curve comes from drawing on a lot of +parallels from the math and techniques + + align:start position:0% +parallels from the math and techniques + + + align:start position:0% +parallels from the math and techniques +that we use for Consumer Theory so we're + + align:start position:0% +that we use for Consumer Theory so we're + + + align:start position:0% +that we use for Consumer Theory so we're +going to start today by talking about + + align:start position:0% +going to start today by talking about + + + align:start position:0% +going to start today by talking about +the key construct a key construct of + + align:start position:0% +the key construct a key construct of + + + align:start position:0% +the key construct a key construct of +producer Theory which is short run cost + + align:start position:0% +producer Theory which is short run cost + + + align:start position:0% +producer Theory which is short run cost +curves remember the short run is the + + align:start position:0% +curves remember the short run is the + + + align:start position:0% +curves remember the short run is the +period of time over which some inputs + + align:start position:0% +period of time over which some inputs + + + align:start position:0% +period of time over which some inputs +are fixed in our case capital and other + + align:start position:0% +are fixed in our case capital and other + + + align:start position:0% +are fixed in our case capital and other +inputs are variable in our case labor + + align:start position:0% +inputs are variable in our case labor + + + align:start position:0% +inputs are variable in our case labor +okay so basically we last time developed + + align:start position:0% +okay so basically we last time developed + + + align:start position:0% +okay so basically we last time developed +a firm production + + align:start position:0% +a firm production + + + align:start position:0% +a firm production +function now I want to translate that + + align:start position:0% +function now I want to translate that + + + align:start position:0% +function now I want to translate that +production function into costs and why + + align:start position:0% +production function into costs and why + + + align:start position:0% +production function into costs and why +do we want to do that because remember + + align:start position:0% +do we want to do that because remember + + + align:start position:0% +do we want to do that because remember +the way firms maximize profits is by + + align:start position:0% +the way firms maximize profits is by + + + align:start position:0% +the way firms maximize profits is by +minimizing costs by producing Goods as + + align:start position:0% +minimizing costs by producing Goods as + + + align:start position:0% +minimizing costs by producing Goods as +efficiently as possible at minimum costs + + align:start position:0% +efficiently as possible at minimum costs + + + align:start position:0% +efficiently as possible at minimum costs +remember a production function from last + + align:start position:0% +remember a production function from last + + + align:start position:0% +remember a production function from last +time was little Q equals the square root + + align:start position:0% +time was little Q equals the square root + + + align:start position:0% +time was little Q equals the square root +of L * K + + align:start position:0% +of L * K + + + align:start position:0% +of L * K +okay that was our production function + + align:start position:0% +okay that was our production function + + + align:start position:0% +okay that was our production function +now what we want to do today is write + + align:start position:0% +now what we want to do today is write + + + align:start position:0% +now what we want to do today is write +down a new function which is what does + + align:start position:0% +down a new function which is what does + + + align:start position:0% +down a new function which is what does +it cost to produce little Q for any + + align:start position:0% +it cost to produce little Q for any + + + align:start position:0% +it cost to produce little Q for any +given L and K what's it cost well the + + align:start position:0% +given L and K what's it cost well the + + + align:start position:0% +given L and K what's it cost well the +cost of producing producing little Q + + align:start position:0% +cost of producing producing little Q + + + align:start position:0% +cost of producing producing little Q +which is a function of Q is equal to the + + align:start position:0% +which is a function of Q is equal to the + + + align:start position:0% +which is a function of Q is equal to the +amount of capital you have which is + + align:start position:0% +amount of capital you have which is + + + align:start position:0% +amount of capital you have which is +fixed which is I'm sorry which is fixed + + align:start position:0% +fixed which is I'm sorry which is fixed + + + align:start position:0% +fixed which is I'm sorry which is fixed +times the rental rate of capital + + align:start position:0% +times the rental rate of capital + + + align:start position:0% +times the rental rate of capital +remember that's the price of machines is + + align:start position:0% +remember that's the price of machines is + + + align:start position:0% +remember that's the price of machines is +their rental rate plus the amount of + + align:start position:0% +their rental rate plus the amount of + + + align:start position:0% +their rental rate plus the amount of +Labor which is a function of Q times the + + align:start position:0% +Labor which is a function of Q times the + + + align:start position:0% +Labor which is a function of Q times the +wage so basically your choice variable + + align:start position:0% +wage so basically your choice variable + + + align:start position:0% +wage so basically your choice variable +is how many workers you want to have to + + align:start position:0% +is how many workers you want to have to + + + align:start position:0% +is how many workers you want to have to +decide how much Q you want to produce + + align:start position:0% +decide how much Q you want to produce + + + align:start position:0% +decide how much Q you want to produce +you're going to decide how many hours of + + align:start position:0% +you're going to decide how many hours of + + + align:start position:0% +you're going to decide how many hours of +Labor or workers you want to employ by + + align:start position:0% +Labor or workers you want to employ by + + + align:start position:0% +Labor or workers you want to employ by +the way I will talk + + align:start position:0% +the way I will talk + + + align:start position:0% +the way I will talk +interchangeably between hours of Labor + + align:start position:0% +interchangeably between hours of Labor + + + align:start position:0% +interchangeably between hours of Labor +and workers there's no right measure of + + align:start position:0% +and workers there's no right measure of + + + align:start position:0% +and workers there's no right measure of +L it depends on the context Etc so don't + + align:start position:0% +L it depends on the context Etc so don't + + + align:start position:0% +L it depends on the context Etc so don't +feel like it's just two different ways + + align:start position:0% +feel like it's just two different ways + + + align:start position:0% +feel like it's just two different ways +of measuring the L input so uh it + + align:start position:0% +of measuring the L input so uh it + + + align:start position:0% +of measuring the L input so uh it +matters less when I say hours of work + + align:start position:0% +matters less when I say hours of work + + + align:start position:0% +matters less when I say hours of work +versus workers if it's an important + + align:start position:0% +versus workers if it's an important + + + align:start position:0% +versus workers if it's an important +distinction I'll tell you but right now + + align:start position:0% +distinction I'll tell you but right now + + + align:start position:0% +distinction I'll tell you but right now +I'm using two different ways of + + align:start position:0% +I'm using two different ways of + + + align:start position:0% +I'm using two different ways of +measuring L the bottom line is it's a + + align:start position:0% +measuring L the bottom line is it's a + + + align:start position:0% +measuring L the bottom line is it's a +labor + + align:start position:0% +labor + + + align:start position:0% +labor +input okay so now + + align:start position:0% +input okay so now + + + align:start position:0% +input okay so now +we want to um say what is the explicit + + align:start position:0% +we want to um say what is the explicit + + + align:start position:0% +we want to um say what is the explicit +expression for the cost function well in + + align:start position:0% +expression for the cost function well in + + + align:start position:0% +expression for the cost function well in +fact if we know a production function + + align:start position:0% +fact if we know a production function + + + align:start position:0% +fact if we know a production function +and we know W and R we can write down a + + align:start position:0% +and we know W and R we can write down a + + + align:start position:0% +and we know W and R we can write down a +cost function so we know this production + + align:start position:0% +cost function so we know this production + + + align:start position:0% +cost function so we know this production +function and let's assume for this case + + align:start position:0% +function and let's assume for this case + + + align:start position:0% +function and let's assume for this case +let's assume W equals 5 and R equals 10 + + align:start position:0% +let's assume W equals 5 and R equals 10 + + + align:start position:0% +let's assume W equals 5 and R equals 10 +okay where those come from I'll teach + + align:start position:0% +okay where those come from I'll teach + + + align:start position:0% +okay where those come from I'll teach +you that in a few lectures remember we + + align:start position:0% +you that in a few lectures remember we + + + align:start position:0% +you that in a few lectures remember we +sort of peeled the onion in this class + + align:start position:0% +sort of peeled the onion in this class + + + align:start position:0% +sort of peeled the onion in this class +we're kind of revealing the m slowly + + align:start position:0% +we're kind of revealing the m slowly + + + align:start position:0% +we're kind of revealing the m slowly +right now just take those as given in a + + align:start position:0% +right now just take those as given in a + + + align:start position:0% +right now just take those as given in a +few lect I'll tell you where they come + + align:start position:0% +few lect I'll tell you where they come + + + align:start position:0% +few lect I'll tell you where they come +from okay so we know the production + + align:start position:0% +from okay so we know the production + + + align:start position:0% +from okay so we know the production +function is qal squ of L * K so we can + + align:start position:0% +function is qal squ of L * K so we can + + + align:start position:0% +function is qal squ of L * K so we can +take that from that production function + + align:start position:0% +take that from that production function + + + align:start position:0% +take that from that production function +we can just flip it and say Lal Q ^2 + + align:start position:0% +we can just flip it and say Lal Q ^2 + + + align:start position:0% +we can just flip it and say Lal Q ^2 +over K bar right just squaring that + + align:start position:0% +over K bar right just squaring that + + + align:start position:0% +over K bar right just squaring that +moving to the other side okay so then we + + align:start position:0% +moving to the other side okay so then we + + + align:start position:0% +moving to the other side okay so then we +could say that we can rewrite the cost + + align:start position:0% +could say that we can rewrite the cost + + + align:start position:0% +could say that we can rewrite the cost +function as C equals 10 K + + align:start position:0% +function as C equals 10 K + + + align:start position:0% +function as C equals 10 K +Bar okay because 10 is the rental + + align:start position:0% +Bar okay because 10 is the rental + + + align:start position:0% +Bar okay because 10 is the rental +rate plus five q^2 over K Bar because + + align:start position:0% +rate plus five q^2 over K Bar because + + + align:start position:0% +rate plus five q^2 over K Bar because +plug in from this equation five is the + + align:start position:0% +plug in from this equation five is the + + + align:start position:0% +plug in from this equation five is the +wage + + align:start position:0% +wage + + + align:start position:0% +wage +rate okay now K bar is a fixed number to + + align:start position:0% +rate okay now K bar is a fixed number to + + + align:start position:0% +rate okay now K bar is a fixed number to +make life easy let's just assume K Bar + + align:start position:0% +make life easy let's just assume K Bar + + + align:start position:0% +make life easy let's just assume K Bar +equals one it could be any fixed number + + align:start position:0% +equals one it could be any fixed number + + + align:start position:0% +equals one it could be any fixed number +in the short run let's assume K bar is + + align:start position:0% +in the short run let's assume K bar is + + + align:start position:0% +in the short run let's assume K bar is +one to make life easy so that says that + + align:start position:0% +one to make life easy so that says that + + + align:start position:0% +one to make life easy so that says that +the cost function we could simply write + + align:start position:0% +the cost function we could simply write + + + align:start position:0% +the cost function we could simply write +as 10 + 5 + + align:start position:0% +as 10 + 5 + + + align:start position:0% +as 10 + 5 +q^2 that's our cost function to get that + + align:start position:0% +q^2 that's our cost function to get that + + + align:start position:0% +q^2 that's our cost function to get that +cost + + align:start position:0% +cost + + + align:start position:0% +cost +function which is a relationship between + + align:start position:0% +function which is a relationship between + + + align:start position:0% +function which is a relationship between +the cost of the firm and the quantity + + align:start position:0% +the cost of the firm and the quantity + + + align:start position:0% +the cost of the firm and the quantity +they produce okay the cost function + + align:start position:0% +they produce okay the cost function + + + align:start position:0% +they produce okay the cost function +relates the quantity produced to the + + align:start position:0% +relates the quantity produced to the + + + align:start position:0% +relates the quantity produced to the +cost all we do is start with the + + align:start position:0% +cost all we do is start with the + + + align:start position:0% +cost all we do is start with the +production function plug in these + + align:start position:0% +production function plug in these + + + align:start position:0% +production function plug in these +parameters and we end up with a cost + + align:start position:0% +parameters and we end up with a cost + + + align:start position:0% +parameters and we end up with a cost +function okay so that's how you + + align:start position:0% +function okay so that's how you + + + align:start position:0% +function okay so that's how you +translate production to + + align:start position:0% +translate production to + + + align:start position:0% +translate production to +cost okay + + align:start position:0% +cost okay + + + align:start position:0% +cost okay +now let's look at this cost function for + + align:start position:0% +now let's look at this cost function for + + + align:start position:0% +now let's look at this cost function for +a second and and I want to give you some + + align:start position:0% +a second and and I want to give you some + + + align:start position:0% +a second and and I want to give you some +key definitions that we'll be using + + align:start position:0% +key definitions that we'll be using + + + align:start position:0% +key definitions that we'll be using +throughout this + + align:start position:0% +throughout this + + + align:start position:0% +throughout this +course okay we are going to + + align:start position:0% +course okay we are going to + + + align:start position:0% +course okay we are going to +call fixed + + align:start position:0% +call fixed + + + align:start position:0% +call fixed +costs fixed + + align:start position:0% +costs fixed + + + align:start position:0% +costs fixed +costs are going to be costs which are + + align:start position:0% +costs are going to be costs which are + + + align:start position:0% +costs are going to be costs which are +not variable in the short + + align:start position:0% +not variable in the short + + + align:start position:0% +not variable in the short +run fixed costs are costs which are not + + align:start position:0% +run fixed costs are costs which are not + + + align:start position:0% +run fixed costs are costs which are not +variable in the short run here it's 10 + + align:start position:0% +variable in the short run here it's 10 + + + align:start position:0% +variable in the short run here it's 10 +the fixed cost in this example is 10 + + align:start position:0% +the fixed cost in this example is 10 + + + align:start position:0% +the fixed cost in this example is 10 +there's nothing you can do in the short + + align:start position:0% +there's nothing you can do in the short + + + align:start position:0% +there's nothing you can do in the short +run to change your fixed cost because + + align:start position:0% +run to change your fixed cost because + + + align:start position:0% +run to change your fixed cost because +capital's + + align:start position:0% +capital's + + + align:start position:0% +capital's +fixed variable + + align:start position:0% +fixed variable + + + align:start position:0% +fixed variable +costs are the costs that can be varied + + align:start position:0% +costs are the costs that can be varied + + + align:start position:0% +costs are the costs that can be varied +in the short run in our case variable + + align:start position:0% +in the short run in our case variable + + + align:start position:0% +in the short run in our case variable +costs are 5 + + align:start position:0% +costs are 5 + + + align:start position:0% +costs are 5 +q^2 so your variable costs are 5 q^ squ + + align:start position:0% +q^2 so your variable costs are 5 q^ squ + + + align:start position:0% +q^2 so your variable costs are 5 q^ squ +that's the part of cost that you can + + align:start position:0% +that's the part of cost that you can + + + align:start position:0% +that's the part of cost that you can +move in the short + + align:start position:0% + + + + align:start position:0% + +run and total costs is the sum of those + + align:start position:0% +run and total costs is the sum of those + + + align:start position:0% +run and total costs is the sum of those +two as expressed there total cost is the + + align:start position:0% +two as expressed there total cost is the + + + align:start position:0% +two as expressed there total cost is the +sum of fixed and variable + + align:start position:0% +sum of fixed and variable + + + align:start position:0% +sum of fixed and variable +costs now the + + align:start position:0% +costs now the + + + align:start position:0% +costs now the +key the the single key that will drive + + align:start position:0% +key the the single key that will drive + + + align:start position:0% +key the the single key that will drive +production theory is what we're going to + + align:start position:0% +production theory is what we're going to + + + align:start position:0% +production theory is what we're going to +call marginal costs marginal costs is + + align:start position:0% +call marginal costs marginal costs is + + + align:start position:0% +call marginal costs marginal costs is +the + + align:start position:0% +the + + + align:start position:0% +the +differential of total costs with respect + + align:start position:0% +differential of total costs with respect + + + align:start position:0% +differential of total costs with respect +to + + align:start position:0% +to + + + align:start position:0% +to +quantity okay so marginal cost is DC + + align:start position:0% +quantity okay so marginal cost is DC + + + align:start position:0% +quantity okay so marginal cost is DC +DQ which G given that fixed costs are + + align:start position:0% +DQ which G given that fixed costs are + + + align:start position:0% +DQ which G given that fixed costs are +fixed in the short run it's the same as + + align:start position:0% +fixed in the short run it's the same as + + + align:start position:0% +fixed in the short run it's the same as +saying D variable cost + + align:start position:0% +saying D variable cost + + + align:start position:0% +saying D variable cost +DQ okay in the short run D total cost DQ + + align:start position:0% +DQ okay in the short run D total cost DQ + + + align:start position:0% +DQ okay in the short run D total cost DQ +is the same as D variable cost DQ + + align:start position:0% +is the same as D variable cost DQ + + + align:start position:0% +is the same as D variable cost DQ +because fixed costs are + + align:start position:0% +because fixed costs are + + + align:start position:0% +because fixed costs are +fixed okay so marginal costs are the + + align:start position:0% +fixed okay so marginal costs are the + + + align:start position:0% +fixed okay so marginal costs are the +marginal cost of producing the next unit + + align:start position:0% +marginal cost of producing the next unit + + + align:start position:0% +marginal cost of producing the next unit +what is the cost to produ of the next + + align:start position:0% +what is the cost to produ of the next + + + align:start position:0% +what is the cost to produ of the next +unit it's the change in variable costs + + align:start position:0% +unit it's the change in variable costs + + + align:start position:0% +unit it's the change in variable costs +for the next unit + + align:start position:0% +for the next unit + + + align:start position:0% +for the next unit +produced and then finally we'll Define + + align:start position:0% +produced and then finally we'll Define + + + align:start position:0% +produced and then finally we'll Define +average cost is what they sound like + + align:start position:0% +average cost is what they sound like + + + align:start position:0% +average cost is what they sound like +which is C over Q total cost over + + align:start position:0% +which is C over Q total cost over + + + align:start position:0% +which is C over Q total cost over +quantity produced that's average + + align:start position:0% +quantity produced that's average + + + align:start position:0% +quantity produced that's average +cost we can graph these various cost + + align:start position:0% +cost we can graph these various cost + + + align:start position:0% +cost we can graph these various cost +Curves in figure + + align:start position:0% +Curves in figure + + + align:start position:0% +Curves in figure +61 so figure 61 in your handout shows + + align:start position:0% +61 so figure 61 in your handout shows + + + align:start position:0% +61 so figure 61 in your handout shows +the cost curves for our sample cost + + align:start position:0% +the cost curves for our sample cost + + + align:start position:0% +the cost curves for our sample cost +function which remember is really our + + align:start position:0% +function which remember is really our + + + align:start position:0% +function which remember is really our +example production function given in RW + + align:start position:0% +example production function given in RW + + + align:start position:0% +example production function given in RW +and K Bar what you see here is the + + align:start position:0% +and K Bar what you see here is the + + + align:start position:0% +and K Bar what you see here is the +marginal + + align:start position:0% +marginal + + + align:start position:0% +marginal +cost that is D variable cost DQ + + align:start position:0% +cost that is D variable cost DQ + + + align:start position:0% +cost that is D variable cost DQ +is equal in our example to 10 Q just + + align:start position:0% +is equal in our example to 10 Q just + + + align:start position:0% +is equal in our example to 10 Q just +differentiating that with respect to Q + + align:start position:0% +differentiating that with respect to Q + + + align:start position:0% +differentiating that with respect to Q +is 10 Q our marginal costs are are the + + align:start position:0% +is 10 Q our marginal costs are are the + + + align:start position:0% +is 10 Q our marginal costs are are the +line with the equation 10 + + align:start position:0% +line with the equation 10 + + + align:start position:0% +line with the equation 10 +Q our average + + align:start position:0% +Q our average + + + align:start position:0% +Q our average +costs are this expression over Q so it's + + align:start position:0% +costs are this expression over Q so it's + + + align:start position:0% +costs are this expression over Q so it's +10 over Q + 5 + + align:start position:0% +10 over Q + 5 + + + align:start position:0% +10 over Q + 5 +Q 10 over Q + 5 q is average cost + + align:start position:0% +Q 10 over Q + 5 q is average cost + + + align:start position:0% +Q 10 over Q + 5 q is average cost +okay how did I get that it's divide the + + align:start position:0% +okay how did I get that it's divide the + + + align:start position:0% +okay how did I get that it's divide the +cost by Q okay also on this graph you + + align:start position:0% +cost by Q okay also on this graph you + + + align:start position:0% +cost by Q okay also on this graph you +can see average variable costs and + + align:start position:0% +can see average variable costs and + + + align:start position:0% +can see average variable costs and +average fixed cost so you can see that + + align:start position:0% +average fixed cost so you can see that + + + align:start position:0% +average fixed cost so you can see that +the average cost line is a combination + + align:start position:0% +the average cost line is a combination + + + align:start position:0% +the average cost line is a combination +of two pieces an average variable cost + + align:start position:0% +of two pieces an average variable cost + + + align:start position:0% +of two pieces an average variable cost +which is everywhere up sloping upward + + align:start position:0% +which is everywhere up sloping upward + + + align:start position:0% +which is everywhere up sloping upward +sloping and average fixed cost which is + + align:start position:0% +sloping and average fixed cost which is + + + align:start position:0% +sloping and average fixed cost which is +everywhere fall which is everywhere + + align:start position:0% +everywhere fall which is everywhere + + + align:start position:0% +everywhere fall which is everywhere +falling okay so average costs themselves + + align:start position:0% +falling okay so average costs themselves + + + align:start position:0% +falling okay so average costs themselves +first fall then rise + + align:start position:0% +first fall then rise + + + align:start position:0% +first fall then rise +PR average cost First fall then rise why + + align:start position:0% +PR average cost First fall then rise why + + + align:start position:0% +PR average cost First fall then rise why +is that well that's because at first you + + align:start position:0% +is that well that's because at first you + + + align:start position:0% +is that well that's because at first you +have these big fixed costs you have to + + align:start position:0% +have these big fixed costs you have to + + + align:start position:0% +have these big fixed costs you have to +sort of pay off but over time the fixed + + align:start position:0% +sort of pay off but over time the fixed + + + align:start position:0% +sort of pay off but over time the fixed +cost gets small well the variable cost + + align:start position:0% +cost gets small well the variable cost + + + align:start position:0% +cost gets small well the variable cost +so over time it + + align:start position:0% +so over time it + + + align:start position:0% +so over time it +rises okay so average costs are the + + align:start position:0% +rises okay so average costs are the + + + align:start position:0% +rises okay so average costs are the +first fall because the first couple + + align:start position:0% +first fall because the first couple + + + align:start position:0% +first fall because the first couple +units your costs are very high your + + align:start position:0% +units your costs are very high your + + + align:start position:0% +units your costs are very high your +costs are super high at the start + + align:start position:0% +costs are super high at the start + + + align:start position:0% +costs are super high at the start +because you got all these fixed costs + + align:start position:0% +because you got all these fixed costs + + + align:start position:0% +because you got all these fixed costs +each unit you those fixed costs per unit + + align:start position:0% +each unit you those fixed costs per unit + + + align:start position:0% +each unit you those fixed costs per unit +fall and fall and fall that's the AFC + + align:start position:0% +fall and fall and fall that's the AFC + + + align:start position:0% +fall and fall and fall that's the AFC +loan + + align:start position:0% +loan + + + align:start position:0% +loan +fixed cost per unit fall and fall and + + align:start position:0% +fixed cost per unit fall and fall and + + + align:start position:0% +fixed cost per unit fall and fall and +fall whereas Mar variable cost per unit + + align:start position:0% +fall whereas Mar variable cost per unit + + + align:start position:0% +fall whereas Mar variable cost per unit +rise and rise and rise and the + + align:start position:0% +rise and rise and rise and the + + + align:start position:0% +rise and rise and rise and the +minimum of average cost is where it + + align:start position:0% +minimum of average cost is where it + + + align:start position:0% +minimum of average cost is where it +crosses the marginal cost curve it's + + align:start position:0% +crosses the marginal cost curve it's + + + align:start position:0% +crosses the marginal cost curve it's +just mathematical the minimum if you + + align:start position:0% +just mathematical the minimum if you + + + align:start position:0% +just mathematical the minimum if you +take a function the minimum of the + + align:start position:0% +take a function the minimum of the + + + align:start position:0% +take a function the minimum of the +average is going to be where it + + align:start position:0% +average is going to be where it + + + align:start position:0% +average is going to be where it +intersects the margin okay because + + align:start position:0% +intersects the margin okay because + + + align:start position:0% +intersects the margin okay because +wherever the average cost is wherever + + align:start position:0% +wherever the average cost is wherever + + + align:start position:0% +wherever the average cost is wherever +the marginal cost is above the average + + align:start position:0% +the marginal cost is above the average + + + align:start position:0% +the marginal cost is above the average +cost the average cost is rising wherever + + align:start position:0% +cost the average cost is rising wherever + + + align:start position:0% +cost the average cost is rising wherever +the marginal cost is below the average + + align:start position:0% +the marginal cost is below the average + + + align:start position:0% +the marginal cost is below the average +cost that's falling therefore marginal + + align:start position:0% +cost that's falling therefore marginal + + + align:start position:0% +cost that's falling therefore marginal +cost intersects average costs at the + + align:start position:0% +cost intersects average costs at the + + + align:start position:0% +cost intersects average costs at the +minimum okay in other words if average + + align:start position:0% +minimum okay in other words if average + + + align:start position:0% +minimum okay in other words if average +cost if you're to the point to the left + + align:start position:0% +cost if you're to the point to the left + + + align:start position:0% +cost if you're to the point to the left +of + + align:start position:0% +of + + + align:start position:0% +of +1.5 if you're Rising less than 1.5 units + + align:start position:0% +1.5 if you're Rising less than 1.5 units + + + align:start position:0% +1.5 if you're Rising less than 1.5 units +marginal cost is below average + + align:start position:0% +marginal cost is below average + + + align:start position:0% +marginal cost is below average +costs okay so by producing more you + + align:start position:0% +costs okay so by producing more you + + + align:start position:0% +costs okay so by producing more you +drive average cost down because the + + align:start position:0% +drive average cost down because the + + + align:start position:0% +drive average cost down because the +marginal cost is less than the average + + align:start position:0% +marginal cost is less than the average + + + align:start position:0% +marginal cost is less than the average +cost so as you increase production from + + align:start position:0% +cost so as you increase production from + + + align:start position:0% +cost so as you increase production from +one unit to one and a half unit you + + align:start position:0% +one unit to one and a half unit you + + + align:start position:0% +one unit to one and a half unit you +drive average cost down but once + + align:start position:0% +drive average cost down but once + + + align:start position:0% +drive average cost down but once +marginal cost is above average cost + + align:start position:0% +marginal cost is above average cost + + + align:start position:0% +marginal cost is above average cost +increasing production drives average + + align:start position:0% +increasing production drives average + + + align:start position:0% +increasing production drives average +cost up and that's why marginal cost + + align:start position:0% +cost up and that's why marginal cost + + + align:start position:0% +cost up and that's why marginal cost +hits average cost at the + + align:start position:0% +hits average cost at the + + + align:start position:0% +hits average cost at the +minimum okay questions about those + + align:start position:0% +minimum okay questions about those + + + align:start position:0% +minimum okay questions about those +relationships are those + + align:start position:0% + + + + align:start position:0% + +graphs okay so + + align:start position:0% +graphs okay so + + + align:start position:0% +graphs okay so +now let's go back and note a key + + align:start position:0% +now let's go back and note a key + + + align:start position:0% +now let's go back and note a key +relationship between marginal cost and + + align:start position:0% +relationship between marginal cost and + + + align:start position:0% +relationship between marginal cost and +something we discussed last time the + + align:start position:0% +something we discussed last time the + + + align:start position:0% +something we discussed last time the +marginal product of + + align:start position:0% +marginal product of + + + align:start position:0% +marginal product of +labor okay remember + + align:start position:0% +labor okay remember + + + align:start position:0% +labor okay remember +cost + + align:start position:0% +cost + + + align:start position:0% +cost +equals uh K Bar * r+ L * + + align:start position:0% +equals uh K Bar * r+ L * + + + align:start position:0% +equals uh K Bar * r+ L * +W if you differentiate this with respect + + align:start position:0% +W if you differentiate this with respect + + + align:start position:0% +W if you differentiate this with respect +to Q to get the marginal cost you get + + align:start position:0% +to Q to get the marginal cost you get + + + align:start position:0% +to Q to get the marginal cost you get +marginal + + align:start position:0% +marginal + + + align:start position:0% +marginal +cost equals W * DL DQ okay because this + + align:start position:0% +cost equals W * DL DQ okay because this + + + align:start position:0% +cost equals W * DL DQ okay because this +term drops out and so you just + + align:start position:0% +term drops out and so you just + + + align:start position:0% +term drops out and so you just +differentiate differentiate by the law + + align:start position:0% +differentiate differentiate by the law + + + align:start position:0% +differentiate differentiate by the law +of of you get W time dld + + align:start position:0% +of of you get W time dld + + + align:start position:0% +of of you get W time dld +DQ okay so the marginal cost of + + align:start position:0% +DQ okay so the marginal cost of + + + align:start position:0% +DQ okay so the marginal cost of +producing the next unit is the price per + + align:start position:0% +producing the next unit is the price per + + + align:start position:0% +producing the next unit is the price per +unit of + + align:start position:0% +unit of + + + align:start position:0% +unit of +Labor times how many units of Labor it + + align:start position:0% +Labor times how many units of Labor it + + + align:start position:0% +Labor times how many units of Labor it +takes to make the next unit this is the + + align:start position:0% +takes to make the next unit this is the + + + align:start position:0% +takes to make the next unit this is the +price per unit of Labor W this is how + + align:start position:0% +price per unit of Labor W this is how + + + align:start position:0% +price per unit of Labor W this is how +much labor takes to make the next unit + + align:start position:0% +much labor takes to make the next unit + + + align:start position:0% +much labor takes to make the next unit +so the marginal cost of the next unit is + + align:start position:0% +so the marginal cost of the next unit is + + + align:start position:0% +so the marginal cost of the next unit is +the product of those + + align:start position:0% +the product of those + + + align:start position:0% +the product of those +but we also know from last + + align:start position:0% +but we also know from last + + + align:start position:0% +but we also know from last +lecture we know from last lecture that + + align:start position:0% +lecture we know from last lecture that + + + align:start position:0% +lecture we know from last lecture that +DQ DL we had a name for that we called + + align:start position:0% +DQ DL we had a name for that we called + + + align:start position:0% +DQ DL we had a name for that we called +that the marginal product of labor we + + align:start position:0% +that the marginal product of labor we + + + align:start position:0% +that the marginal product of labor we +defined that last lecture how productive + + align:start position:0% +defined that last lecture how productive + + + align:start position:0% +defined that last lecture how productive +the next unit of Labor is was + + align:start position:0% +the next unit of Labor is was + + + align:start position:0% +the next unit of Labor is was +dql so we can substitute in to write we + + align:start position:0% +dql so we can substitute in to write we + + + align:start position:0% +dql so we can substitute in to write we +can substitute that in to write that + + align:start position:0% +can substitute that in to write that + + + align:start position:0% +can substitute that in to write that +marginal cost equals W over the marginal + + align:start position:0% +marginal cost equals W over the marginal + + + align:start position:0% +marginal cost equals W over the marginal +product of labor + + align:start position:0% + + + + align:start position:0% + +that is the marginal cost producing the + + align:start position:0% +that is the marginal cost producing the + + + align:start position:0% +that is the marginal cost producing the +next unit of the good is higher the more + + align:start position:0% +next unit of the good is higher the more + + + align:start position:0% +next unit of the good is higher the more +you have to pay each worker and lower + + align:start position:0% +you have to pay each worker and lower + + + align:start position:0% +you have to pay each worker and lower +the more productive each worker + + align:start position:0% +the more productive each worker + + + align:start position:0% +the more productive each worker +is okay so as marginal product of labor + + align:start position:0% +is okay so as marginal product of labor + + + align:start position:0% +is okay so as marginal product of labor +is very high unless wages very high + + align:start position:0% +is very high unless wages very high + + + align:start position:0% +is very high unless wages very high +marginal cost is going to be + + align:start position:0% +marginal cost is going to be + + + align:start position:0% +marginal cost is going to be +low okay so basically what's going to + + align:start position:0% +low okay so basically what's going to + + + align:start position:0% +low okay so basically what's going to +matter is the marginal uh the + + align:start position:0% +matter is the marginal uh the + + + align:start position:0% +matter is the marginal uh the +marginal product of each unit of Labor + + align:start position:0% +marginal product of each unit of Labor + + + align:start position:0% +marginal product of each unit of Labor +and the wage of to pay for that + + align:start position:0% +and the wage of to pay for that + + + align:start position:0% +and the wage of to pay for that +unit okay now last point I want to make + + align:start position:0% +unit okay now last point I want to make + + + align:start position:0% +unit okay now last point I want to make +here on on definitions I want about + + align:start position:0% +here on on definitions I want about + + + align:start position:0% +here on on definitions I want about +something called sunk + + align:start position:0% +something called sunk + + + align:start position:0% +something called sunk +costs I'm gonna I'm GNA already + + align:start position:0% +costs I'm gonna I'm GNA already + + + align:start position:0% +costs I'm gonna I'm GNA already +contradict something I said last lecture + + align:start position:0% +contradict something I said last lecture + + + align:start position:0% +contradict something I said last lecture +last lecture I said in the long run all + + align:start position:0% +last lecture I said in the long run all + + + align:start position:0% +last lecture I said in the long run all +inputs are variable in the short run + + align:start position:0% +inputs are variable in the short run + + + align:start position:0% +inputs are variable in the short run +only some inputs are variable we have + + align:start position:0% +only some inputs are variable we have + + + align:start position:0% +only some inputs are variable we have +some costs which in the we have some + + align:start position:0% +some costs which in the we have some + + + align:start position:0% +some costs which in the we have some +costs which in the long run are not + + align:start position:0% +costs which in the long run are not + + + align:start position:0% +costs which in the long run are not +variable those are called sunk costs + + align:start position:0% +variable those are called sunk costs + + + align:start position:0% +variable those are called sunk costs +those are costs where once you make them + + align:start position:0% +those are costs where once you make them + + + align:start position:0% +those are costs where once you make them +you can never get them + + align:start position:0% +you can never get them + + + align:start position:0% +you can never get them +back a fixed cost is something like a + + align:start position:0% +back a fixed cost is something like a + + + align:start position:0% +back a fixed cost is something like a +machine if you buy a machine and you + + align:start position:0% +machine if you buy a machine and you + + + align:start position:0% +machine if you buy a machine and you +want to get rid of it you can sell that + + align:start position:0% +want to get rid of it you can sell that + + + align:start position:0% +want to get rid of it you can sell that +machine or a building if you buy a + + align:start position:0% +machine or a building if you buy a + + + align:start position:0% +machine or a building if you buy a +building and you want rid of it you can + + align:start position:0% +building and you want rid of it you can + + + align:start position:0% +building and you want rid of it you can +sell that building a sun cost is + + align:start position:0% +sell that building a sun cost is + + + align:start position:0% +sell that building a sun cost is +something you can't ever get rid of or + + align:start position:0% +something you can't ever get rid of or + + + align:start position:0% +something you can't ever get rid of or +sell the best example would be med + + align:start position:0% +sell the best example would be med + + + align:start position:0% +sell the best example would be med +school if you want to be a doctor you + + align:start position:0% +school if you want to be a doctor you + + + align:start position:0% +school if you want to be a doctor you +have to go to med + + align:start position:0% +have to go to med + + + align:start position:0% +have to go to med +school having gone to med school school + + align:start position:0% +school having gone to med school school + + + align:start position:0% +school having gone to med school school +you can't ever ungo to med school you + + align:start position:0% +you can't ever ungo to med school you + + + align:start position:0% +you can't ever ungo to med school you +have paid that cost of time and money + + align:start position:0% +have paid that cost of time and money + + + align:start position:0% +have paid that cost of time and money +and you're done it's + + align:start position:0% +and you're done it's + + + align:start position:0% +and you're done it's +sunk a sunk cost is essentially a long + + align:start position:0% +sunk a sunk cost is essentially a long + + + align:start position:0% +sunk a sunk cost is essentially a long +run fixed cost it's something where once + + align:start position:0% +run fixed cost it's something where once + + + align:start position:0% +run fixed cost it's something where once +you make that investment you never get + + align:start position:0% +you make that investment you never get + + + align:start position:0% +you make that investment you never get +it there's no way to get it back now you + + align:start position:0% +it there's no way to get it back now you + + + align:start position:0% +it there's no way to get it back now you +can get benefits from it I'm not saying + + align:start position:0% +can get benefits from it I'm not saying + + + align:start position:0% +can get benefits from it I'm not saying +it's not a good idea I'm just saying + + align:start position:0% +it's not a good idea I'm just saying + + + align:start position:0% +it's not a good idea I'm just saying +unlike a building which you could sell + + align:start position:0% +unlike a building which you could sell + + + align:start position:0% +unlike a building which you could sell +or a machine which you could sell med + + align:start position:0% +or a machine which you could sell med + + + align:start position:0% +or a machine which you could sell med +school you can't sell your med school + + align:start position:0% +school you can't sell your med school + + + align:start position:0% +school you can't sell your med school +experience okay and this is very + + align:start position:0% +experience okay and this is very + + + align:start position:0% +experience okay and this is very +important important because it leads to + + align:start position:0% +important important because it leads to + + + align:start position:0% +important important because it leads to +a very + + align:start position:0% +a very + + + align:start position:0% +a very +counterintuitive difference between sunk + + align:start position:0% +counterintuitive difference between sunk + + + align:start position:0% +counterintuitive difference between sunk +costs and fixed costs something that + + align:start position:0% +costs and fixed costs something that + + + align:start position:0% +costs and fixed costs something that +trips people up all the + + align:start position:0% +trips people up all the + + + align:start position:0% +trips people up all the +time which is that sunk costs are + + align:start position:0% +time which is that sunk costs are + + + align:start position:0% +time which is that sunk costs are +irrelevant to decision making once + + align:start position:0% +irrelevant to decision making once + + + align:start position:0% +irrelevant to decision making once +they're + + align:start position:0% +they're + + + align:start position:0% +they're +paid once you've paid your sunk costs + + align:start position:0% +paid once you've paid your sunk costs + + + align:start position:0% +paid once you've paid your sunk costs +they are relevant because you can't get + + align:start position:0% +they are relevant because you can't get + + + align:start position:0% +they are relevant because you can't get +them back anyway it's done or does The + + align:start position:0% +them back anyway it's done or does The + + + align:start position:0% +them back anyway it's done or does The +Economist say sunk costs or sunk doesn't + + align:start position:0% +Economist say sunk costs or sunk doesn't + + + align:start position:0% +Economist say sunk costs or sunk doesn't +matter it's + + align:start position:0% +matter it's + + + align:start position:0% +matter it's +irrelevant now here's why that matters + + align:start position:0% +irrelevant now here's why that matters + + + align:start position:0% +irrelevant now here's why that matters +in real life + + align:start position:0% +in real life + + + align:start position:0% +in real life +let me talk about a simple example many + + align:start position:0% +let me talk about a simple example many + + + align:start position:0% +let me talk about a simple example many +of you have heard of the band Journey + + align:start position:0% +of you have heard of the band Journey + + + align:start position:0% +of you have heard of the band Journey +classic 80s band a few years ago Journey + + align:start position:0% +classic 80s band a few years ago Journey + + + align:start position:0% +classic 80s band a few years ago Journey +was touring and they have a new lead + + align:start position:0% +was touring and they have a new lead + + + align:start position:0% +was touring and they have a new lead +singer this guy they fat actually + + align:start position:0% +singer this guy they fat actually + + + align:start position:0% +singer this guy they fat actually +through YouTube who sounds he's from the + + align:start position:0% +through YouTube who sounds he's from the + + + align:start position:0% +through YouTube who sounds he's from the +Philippines sounds just like the old + + align:start position:0% +Philippines sounds just like the old + + + align:start position:0% +Philippines sounds just like the old +lead singer it's kind of cool so uh they + + align:start position:0% +lead singer it's kind of cool so uh they + + + align:start position:0% +lead singer it's kind of cool so uh they +were playing down in uh uh Mansfield + + align:start position:0% +were playing down in uh uh Mansfield + + + align:start position:0% +were playing down in uh uh Mansfield +Mass and I bought a couple of tickets + + align:start position:0% +Mass and I bought a couple of tickets + + + align:start position:0% +Mass and I bought a couple of tickets +for my wife and I for 125 bucks each + + align:start position:0% +for my wife and I for 125 bucks each + + + align:start position:0% +for my wife and I for 125 bucks each +good + + align:start position:0% +good + + + align:start position:0% +good +seats then I looked at the set list and + + align:start position:0% +seats then I looked at the set list and + + + align:start position:0% +seats then I looked at the set list and +I thought you know I don't actually like + + align:start position:0% +I thought you know I don't actually like + + + align:start position:0% +I thought you know I don't actually like +that many Journey songs M there's hour + + align:start position:0% +that many Journey songs M there's hour + + + align:start position:0% +that many Journey songs M there's hour +and a half concert for like the three + + align:start position:0% +and a half concert for like the three + + + align:start position:0% +and a half concert for like the three +songs as I like it doesn't really seem + + align:start position:0% +songs as I like it doesn't really seem + + + align:start position:0% +songs as I like it doesn't really seem +worth it I don't think I want to go I + + align:start position:0% +worth it I don't think I want to go I + + + align:start position:0% +worth it I don't think I want to go I +think I'm going to try to sell these + + align:start position:0% +think I'm going to try to sell these + + + align:start position:0% +think I'm going to try to sell these +tickets on the secondary market so I can + + align:start position:0% +tickets on the secondary market so I can + + + align:start position:0% +tickets on the secondary market so I can +go to Stubhub and sell the tickets the + + align:start position:0% +go to Stubhub and sell the tickets the + + + align:start position:0% +go to Stubhub and sell the tickets the +question + + align:start position:0% +question + + + align:start position:0% +question +is I had paid $250 for those tickets how + + align:start position:0% +is I had paid $250 for those tickets how + + + align:start position:0% +is I had paid $250 for those tickets how +should that impact the price I set on + + align:start position:0% +should that impact the price I set on + + + align:start position:0% +should that impact the price I set on +StubHub the money I paid for those + + align:start position:0% +StubHub the money I paid for those + + + align:start position:0% +StubHub the money I paid for those +tickets how should it that money forget + + align:start position:0% +tickets how should it that money forget + + + align:start position:0% +tickets how should it that money forget +everything else just the money I paid + + align:start position:0% +everything else just the money I paid + + + align:start position:0% +everything else just the money I paid +how should it impact the price I set on + + align:start position:0% +how should it impact the price I set on + + + align:start position:0% +how should it impact the price I set on +StubHub + + align:start position:0% +StubHub + + + align:start position:0% +StubHub +yeah it shouldn't why + + align:start position:0% +yeah it shouldn't why + + + align:start position:0% +yeah it shouldn't why +not it's a some cost I paid it already + + align:start position:0% +not it's a some cost I paid it already + + + align:start position:0% +not it's a some cost I paid it already +it's + + align:start position:0% +it's + + + align:start position:0% +it's +irrelevant it's done I already paid the + + align:start position:0% +irrelevant it's done I already paid the + + + align:start position:0% +irrelevant it's done I already paid the +250 it's gone I might feel sad but it's + + align:start position:0% +250 it's gone I might feel sad but it's + + + align:start position:0% +250 it's gone I might feel sad but it's +gone how should I decide what to put the + + align:start position:0% +gone how should I decide what to put the + + + align:start position:0% +gone how should I decide what to put the +tickets on salale for subhub well it's a + + align:start position:0% +tickets on salale for subhub well it's a + + + align:start position:0% +tickets on salale for subhub well it's a +function of two factors first is I can + + align:start position:0% +function of two factors first is I can + + + align:start position:0% +function of two factors first is I can +look at what things are selling for and + + align:start position:0% +look at what things are selling for and + + + align:start position:0% +look at what things are selling for and +try to use the + + align:start position:0% +try to use the + + + align:start position:0% +try to use the +market that's one thing but let's add no + + align:start position:0% +market that's one thing but let's add no + + + align:start position:0% +market that's one thing but let's add no +information let's add no information on + + align:start position:0% +information let's add no information on + + + align:start position:0% +information let's add no information on +the market leave that aside it's just an + + align:start position:0% +the market leave that aside it's just an + + + align:start position:0% +the market leave that aside it's just an +internal decision decision on what what + + align:start position:0% +internal decision decision on what what + + + align:start position:0% +internal decision decision on what what +I'm willing to sell the tickets for how + + align:start position:0% +I'm willing to sell the tickets for how + + + align:start position:0% +I'm willing to sell the tickets for how +should I + + align:start position:0% +should I + + + align:start position:0% +should I +decide + + align:start position:0% + + + + align:start position:0% + +yeah you well that's one way to think + + align:start position:0% +yeah you well that's one way to think + + + align:start position:0% +yeah you well that's one way to think +about it you'd not be a to pay the buy + + align:start position:0% +about it you'd not be a to pay the buy + + + align:start position:0% +about it you'd not be a to pay the buy +tickets that's one way but there's sort + + align:start position:0% +tickets that's one way but there's sort + + + align:start position:0% +tickets that's one way but there's sort +of a that's sort of a confusing way + + align:start position:0% +of a that's sort of a confusing way + + + align:start position:0% +of a that's sort of a confusing way +there's another way to think about it + + align:start position:0% +there's another way to think about it + + + align:start position:0% +there's another way to think about it +what's another way to think about it's + + align:start position:0% +what's another way to think about it's + + + align:start position:0% +what's another way to think about it's +related to that sort the flip of what + + align:start position:0% +related to that sort the flip of what + + + align:start position:0% +related to that sort the flip of what +you + + align:start position:0% +you + + + align:start position:0% +you +said how should I think about how much + + align:start position:0% +said how should I think about how much + + + align:start position:0% +said how should I think about how much +I'm willing to I'm willing to how much + + align:start position:0% +I'm willing to I'm willing to how much + + + align:start position:0% +I'm willing to I'm willing to how much +am I willing forget the price that I set + + align:start position:0% +am I willing forget the price that I set + + + align:start position:0% +am I willing forget the price that I set +which is a function of what I think the + + align:start position:0% +which is a function of what I think the + + + align:start position:0% +which is a function of what I think the +market is my willingness how much should + + align:start position:0% +market is my willingness how much should + + + align:start position:0% +market is my willingness how much should +I you willing to sell those tickets + + align:start position:0% +I you willing to sell those tickets + + + align:start position:0% +I you willing to sell those tickets +for well think about it if I if I sell + + align:start position:0% +for well think about it if I if I sell + + + align:start position:0% +for well think about it if I if I sell +the tickets what am I not + + align:start position:0% +the tickets what am I not + + + align:start position:0% +the tickets what am I not +doing I'm not going to the + + align:start position:0% +doing I'm not going to the + + + align:start position:0% +doing I'm not going to the +concert so how much should I be willing + + align:start position:0% +concert so how much should I be willing + + + align:start position:0% +concert so how much should I be willing +to sell the tickets + + align:start position:0% +to sell the tickets + + + align:start position:0% +to sell the tickets +for yeah yeah go ahead white shirt you + + align:start position:0% +for yeah yeah go ahead white shirt you + + + align:start position:0% +for yeah yeah go ahead white shirt you +had your hand up + + align:start position:0% +had your hand up + + + align:start position:0% +had your hand up +yeah yeah basically I should sell them + + align:start position:0% +yeah yeah basically I should sell them + + + align:start position:0% +yeah yeah basically I should sell them +for how much I'm willing to pay to go to + + align:start position:0% +for how much I'm willing to pay to go to + + + align:start position:0% +for how much I'm willing to pay to go to +the + + align:start position:0% +the + + + align:start position:0% +the +show if + + align:start position:0% +show if + + + align:start position:0% +show if +literally I don't want to go that I + + align:start position:0% +literally I don't want to go that I + + + align:start position:0% +literally I don't want to go that I +should be willing to sell them for zero + + align:start position:0% +should be willing to sell them for zero + + + align:start position:0% +should be willing to sell them for zero +I should willing to give them away not + + align:start position:0% +I should willing to give them away not + + + align:start position:0% +I should willing to give them away not +saying I will sell them for zero because + + align:start position:0% +saying I will sell them for zero because + + + align:start position:0% +saying I will sell them for zero because +I might make money on it but there's a + + align:start position:0% +I might make money on it but there's a + + + align:start position:0% +I might make money on it but there's a +my underlying opportunity cost at zero + + align:start position:0% +my underlying opportunity cost at zero + + + align:start position:0% +my underlying opportunity cost at zero +because I literally would rather sit at + + align:start position:0% +because I literally would rather sit at + + + align:start position:0% +because I literally would rather sit at +home if I say yeah I don't want to pay + + align:start position:0% +home if I say yeah I don't want to pay + + + align:start position:0% +home if I say yeah I don't want to pay +250 but if you said you get Journey + + align:start position:0% +250 but if you said you get Journey + + + align:start position:0% +250 but if you said you get Journey +tickets for 50 bucks each I'd go then I + + align:start position:0% +tickets for 50 bucks each I'd go then I + + + align:start position:0% +tickets for 50 bucks each I'd go then I +should set the price at 50 bucks each if + + align:start position:0% +should set the price at 50 bucks each if + + + align:start position:0% +should set the price at 50 bucks each if +someone will pay me more than 50 I sell + + align:start position:0% +someone will pay me more than 50 I sell + + + align:start position:0% +someone will pay me more than 50 I sell +them if they'll pay me less than 50 I go + + align:start position:0% +them if they'll pay me less than 50 I go + + + align:start position:0% +them if they'll pay me less than 50 I go +so the amount I should will be willing + + align:start position:0% +so the amount I should will be willing + + + align:start position:0% +so the amount I should will be willing +to get should be determined by the + + align:start position:0% +to get should be determined by the + + + align:start position:0% +to get should be determined by the +opportunity cost of going not by what I + + align:start position:0% +opportunity cost of going not by what I + + + align:start position:0% +opportunity cost of going not by what I +paid for them that is a very confusing + + align:start position:0% +paid for them that is a very confusing + + + align:start position:0% +paid for them that is a very confusing +logic + + align:start position:0% +logic + + + align:start position:0% +logic +yeah but + + align:start position:0% +yeah but + + + align:start position:0% +yeah but +some like + + align:start position:0% +some like + + + align:start position:0% +some like +think you would because that's the way + + align:start position:0% +think you would because that's the way + + + align:start position:0% +think you would because that's the way +humans think but it's + + align:start position:0% +humans think but it's + + + align:start position:0% +humans think but it's +wrong it's not a real + + align:start position:0% + + + + align:start position:0% + +thing but it doesn't matter they're + + align:start position:0% +thing but it doesn't matter they're + + + align:start position:0% +thing but it doesn't matter they're +already gone so once again let me think + + align:start position:0% +already gone so once again let me think + + + align:start position:0% +already gone so once again let me think +of it this way let's say that um you + + align:start position:0% +of it this way let's say that um you + + + align:start position:0% +of it this way let's say that um you +the fact you've paid the costs makes you + + align:start position:0% +the fact you've paid the costs makes you + + + align:start position:0% +the fact you've paid the costs makes you +sad you've you've paid those costs you + + align:start position:0% +sad you've you've paid those costs you + + + align:start position:0% +sad you've you've paid those costs you +made them sad but right now if you + + align:start position:0% +made them sad but right now if you + + + align:start position:0% +made them sad but right now if you +whatever you sell them for okay that's + + align:start position:0% +whatever you sell them for okay that's + + + align:start position:0% +whatever you sell them for okay that's +all you can get back so let's say let me + + align:start position:0% +all you can get back so let's say let me + + + align:start position:0% +all you can get back so let's say let me +put this way let's say I can go online + + align:start position:0% +put this way let's say I can go online + + + align:start position:0% +put this way let's say I can go online +and sell them for 500 bucks each should + + align:start position:0% +and sell them for 500 bucks each should + + + align:start position:0% +and sell them for 500 bucks each should +I only sell them for 250 because that's + + align:start position:0% +I only sell them for 250 because that's + + + align:start position:0% +I only sell them for 250 because that's +what I paid for him no sell them for 500 + + align:start position:0% +what I paid for him no sell them for 500 + + + align:start position:0% +what I paid for him no sell them for 500 +so it's irrelevant that I paid 250 if I + + align:start position:0% +so it's irrelevant that I paid 250 if I + + + align:start position:0% +so it's irrelevant that I paid 250 if I +only sell them for 50 I sell them for 50 + + align:start position:0% +only sell them for 50 I sell them for 50 + + + align:start position:0% +only sell them for 50 I sell them for 50 +I've sell them for 500 sell them for 500 + + align:start position:0% +I've sell them for 500 sell them for 500 + + + align:start position:0% +I've sell them for 500 sell them for 500 +what I paid is some amount I paid in the + + align:start position:0% +what I paid is some amount I paid in the + + + align:start position:0% +what I paid is some amount I paid in the +past I may be sad about it and look let + + align:start position:0% +past I may be sad about it and look let + + + align:start position:0% +past I may be sad about it and look let +me be clear the way you're thinking + + align:start position:0% +me be clear the way you're thinking + + + align:start position:0% +me be clear the way you're thinking +about is the way that the world thinks + + align:start position:0% +about is the way that the world thinks + + + align:start position:0% +about is the way that the world thinks +about it and it's wrong okay um you know + + align:start position:0% +about it and it's wrong okay um you know + + + align:start position:0% +about it and it's wrong okay um you know +I got chastised by my advisor in + + align:start position:0% +I got chastised by my advisor in + + + align:start position:0% +I got chastised by my advisor in +graduate school because I had plane + + align:start position:0% +graduate school because I had plane + + + align:start position:0% +graduate school because I had plane +tickets that I was going to cancel and I + + align:start position:0% +tickets that I was going to cancel and I + + + align:start position:0% +tickets that I was going to cancel and I +was suffering from the Sun cost Val I + + align:start position:0% +was suffering from the Sun cost Val I + + + align:start position:0% +was suffering from the Sun cost Val I +was going to say well I paid this much + + align:start position:0% +was going to say well I paid this much + + + align:start position:0% +was going to say well I paid this much +for him and he said doesn't matter what + + align:start position:0% +for him and he said doesn't matter what + + + align:start position:0% +for him and he said doesn't matter what +you paid for him what matters is the + + align:start position:0% +you paid for him what matters is the + + + align:start position:0% +you paid for him what matters is the +value to you of flying + + align:start position:0% +value to you of flying + + + align:start position:0% +value to you of flying +home okay the sun costs are + + align:start position:0% +home okay the sun costs are + + + align:start position:0% +home okay the sun costs are +gone okay + + align:start position:0% + + + + align:start position:0% + +yeah s selling what + + align:start position:0% +yeah s selling what + + + align:start position:0% +yeah s selling what +build oh so the difference that's a + + align:start position:0% +build oh so the difference that's a + + + align:start position:0% +build oh so the difference that's a +great point the difference is um with + + align:start position:0% +great point the difference is um with + + + align:start position:0% +great point the difference is um with +the + + align:start position:0% +the + + + align:start position:0% +the +building when + + align:start position:0% +building when + + + align:start position:0% +building when +I the difference is um with with the + + align:start position:0% +I the difference is um with with the + + + align:start position:0% +I the difference is um with with the +building I buy it as an investment that + + align:start position:0% +building I buy it as an investment that + + + align:start position:0% +building I buy it as an investment that +I intend to use for a while and then + + align:start position:0% +I intend to use for a while and then + + + align:start position:0% +I intend to use for a while and then +sell with the tickets I just bought that + + align:start position:0% +sell with the tickets I just bought that + + + align:start position:0% +sell with the tickets I just bought that +I wasn't thinking about selling them I + + align:start position:0% +I wasn't thinking about selling them I + + + align:start position:0% +I wasn't thinking about selling them I +was thinking about buying them I mean + + align:start position:0% +was thinking about buying them I mean + + + align:start position:0% +was thinking about buying them I mean +for example I could have bought the + + align:start position:0% +for example I could have bought the + + + align:start position:0% +for example I could have bought the +Journey tickets as an investment like a + + align:start position:0% +Journey tickets as an investment like a + + + align:start position:0% +Journey tickets as an investment like a +building I could have bought the Journey + + align:start position:0% +building I could have bought the Journey + + + align:start position:0% +building I could have bought the Journey +tickets and said well look I'm going to + + align:start position:0% +tickets and said well look I'm going to + + + align:start position:0% +tickets and said well look I'm going to +pay this for them because I at that form + + align:start position:0% +pay this for them because I at that form + + + align:start position:0% +pay this for them because I at that form +I plan to sell them but I wasn't plan to + + align:start position:0% +I plan to sell them but I wasn't plan to + + + align:start position:0% +I plan to sell them but I wasn't plan to +sell them I just bought them I thought I + + align:start position:0% +sell them I just bought them I thought I + + + align:start position:0% +sell them I just bought them I thought I +was done then things changed so from my + + align:start position:0% +was done then things changed so from my + + + align:start position:0% +was done then things changed so from my +new perspective they were + + align:start position:0% +new perspective they were + + + align:start position:0% +new perspective they were +sunk It's a good question good questions + + align:start position:0% +sunk It's a good question good questions + + + align:start position:0% +sunk It's a good question good questions +yeah some costs are basically Goods that + + align:start position:0% +yeah some costs are basically Goods that + + + align:start position:0% +yeah some costs are basically Goods that +you didn't want to sell in the first + + align:start position:0% +you didn't want to sell in the first + + + align:start position:0% +you didn't want to sell in the first +place some costs are things Investments + + align:start position:0% +place some costs are things Investments + + + align:start position:0% +place some costs are things Investments +you + + align:start position:0% +you + + + align:start position:0% +you +make you decide I want to go to med + + align:start position:0% +make you decide I want to go to med + + + align:start position:0% +make you decide I want to go to med +school I want to go to Journey okay and + + align:start position:0% +school I want to go to Journey okay and + + + align:start position:0% +school I want to go to Journey okay and +you make and you make those decisions + + align:start position:0% +you make and you make those decisions + + + align:start position:0% +you make and you make those decisions +and then things change and you may or or + + align:start position:0% +and then things change and you may or or + + + align:start position:0% +and then things change and you may or or +they don't change but the point is + + align:start position:0% +they don't change but the point is + + + align:start position:0% +they don't change but the point is +whatever you want to do next it's + + align:start position:0% +whatever you want to do next it's + + + align:start position:0% +whatever you want to do next it's +irrelevant that you made that decision + + align:start position:0% +irrelevant that you made that decision + + + align:start position:0% +irrelevant that you made that decision +you already made it now the question is + + align:start position:0% +you already made it now the question is + + + align:start position:0% +you already made it now the question is +what to do next it's it's it's it's not + + align:start position:0% +what to do next it's it's it's it's not + + + align:start position:0% +what to do next it's it's it's it's not +it's not an easy concept but it's an + + align:start position:0% +it's not an easy concept but it's an + + + align:start position:0% +it's not an easy concept but it's an +important one + + align:start position:0% + + + + align:start position:0% + +yeah oh you use it and journey buy joury + + align:start position:0% +yeah oh you use it and journey buy joury + + + align:start position:0% +yeah oh you use it and journey buy joury +tickets was the kind of investment that + + align:start position:0% +tickets was the kind of investment that + + + align:start position:0% +tickets was the kind of investment that +I would have used to go to Journey the + + align:start position:0% +I would have used to go to Journey the + + + align:start position:0% +I would have used to go to Journey the +difference if I decide I don't want to + + align:start position:0% +difference if I decide I don't want to + + + align:start position:0% +difference if I decide I don't want to +be a + + align:start position:0% +be a + + + align:start position:0% +be a +doctor let's say being a doctor is + + align:start position:0% +doctor let's say being a doctor is + + + align:start position:0% +doctor let's say being a doctor is +composed to three things going to med + + align:start position:0% +composed to three things going to med + + + align:start position:0% +composed to three things going to med +school buying an office and working + + align:start position:0% +school buying an office and working + + + align:start position:0% +school buying an office and working +every day if I decide I want to be aor + + align:start position:0% +every day if I decide I want to be aor + + + align:start position:0% +every day if I decide I want to be aor +doctor I can stop working every day I + + align:start position:0% +doctor I can stop working every day I + + + align:start position:0% +doctor I can stop working every day I +can sell the office but I can't ungo to + + align:start position:0% +can sell the office but I can't ungo to + + + align:start position:0% +can sell the office but I can't ungo to +med school it's + + align:start position:0% +med school it's + + + align:start position:0% +med school it's +done so my decision tomorrow do I want + + align:start position:0% +done so my decision tomorrow do I want + + + align:start position:0% +done so my decision tomorrow do I want +to stay being a doctor it's irrelevant + + align:start position:0% +to stay being a doctor it's irrelevant + + + align:start position:0% +to stay being a doctor it's irrelevant +if I went to med school I just say well + + align:start position:0% +if I went to med school I just say well + + + align:start position:0% +if I went to med school I just say well +how much do I like it how much money I'm + + align:start position:0% +how much do I like it how much money I'm + + + align:start position:0% +how much do I like it how much money I'm +making Rel to the cost of the office and + + align:start position:0% +making Rel to the cost of the office and + + + align:start position:0% +making Rel to the cost of the office and +the cost of what I have of my time and + + align:start position:0% +the cost of what I have of my time and + + + align:start position:0% +the cost of what I have of my time and +working every + + align:start position:0% +working every + + + align:start position:0% +working every +day + + align:start position:0% +day + + + align:start position:0% +day +okay that these are great questions + + align:start position:0% +okay that these are great questions + + + align:start position:0% +okay that these are great questions +because this is exactly kind of concept + + align:start position:0% +because this is exactly kind of concept + + + align:start position:0% +because this is exactly kind of concept +that I want you to be able to think + + align:start position:0% +that I want you to be able to think + + + align:start position:0% +that I want you to be able to think +differently about coming out of this + + align:start position:0% +differently about coming out of this + + + align:start position:0% +differently about coming out of this +course yeah + + align:start position:0% +course yeah + + + align:start position:0% +course yeah +or at least for some cost does intent + + align:start position:0% +or at least for some cost does intent + + + align:start position:0% +or at least for some cost does intent +matter what's that intent matter well + + align:start position:0% +matter what's that intent matter well + + + align:start position:0% +matter what's that intent matter well +it's it intent matters and whether we + + align:start position:0% +it's it intent matters and whether we + + + align:start position:0% +it's it intent matters and whether we +label it fixed or sunk that was the + + align:start position:0% +label it fixed or sunk that was the + + + align:start position:0% +label it fixed or sunk that was the +question here intent matters if you + + align:start position:0% +question here intent matters if you + + + align:start position:0% +question here intent matters if you +intend to eventually use it and sell it + + align:start position:0% +intend to eventually use it and sell it + + + align:start position:0% +intend to eventually use it and sell it +then it's fixed if you intend if it + + align:start position:0% +then it's fixed if you intend if it + + + align:start position:0% +then it's fixed if you intend if it +can't be sold or you don't intend to + + align:start position:0% +can't be sold or you don't intend to + + + align:start position:0% +can't be sold or you don't intend to +sell it then it's sunk but that that's a + + align:start position:0% +sell it then it's sunk but that that's a + + + align:start position:0% +sell it then it's sunk but that that's a +fuzzy + + align:start position:0% +fuzzy + + + align:start position:0% +fuzzy +line okay all right great discussion + + align:start position:0% +line okay all right great discussion + + + align:start position:0% +line okay all right great discussion +let's go on so now let's talk talk about + + align:start position:0% +let's go on so now let's talk talk about + + + align:start position:0% +let's go on so now let's talk talk about +the long run versus the short + + align:start position:0% + + + + align:start position:0% + +run the long run versus the short + + align:start position:0% + + + + align:start position:0% + +run the difference in the long run let's + + align:start position:0% +run the difference in the long run let's + + + align:start position:0% +run the difference in the long run let's +put Sun cost aside now how many choose + + align:start position:0% +put Sun cost aside now how many choose + + + align:start position:0% +put Sun cost aside now how many choose +let's put them aside okay that's more + + align:start position:0% +let's put them aside okay that's more + + + align:start position:0% +let's put them aside okay that's more +just sort of a fun thing for you to be + + align:start position:0% +just sort of a fun thing for you to be + + + align:start position:0% +just sort of a fun thing for you to be +thinking about in your life but for but + + align:start position:0% +thinking about in your life but for but + + + align:start position:0% +thinking about in your life but for but +for the rest for most of us class we'll + + align:start position:0% +for the rest for most of us class we'll + + + align:start position:0% +for the rest for most of us class we'll +talk about cost being fixed or variable + + align:start position:0% +talk about cost being fixed or variable + + + align:start position:0% +talk about cost being fixed or variable +not sunk so let's go back to where we + + align:start position:0% +not sunk so let's go back to where we + + + align:start position:0% +not sunk so let's go back to where we +just fixed and variable costs and we + + align:start position:0% +just fixed and variable costs and we + + + align:start position:0% +just fixed and variable costs and we +want to ask how do costs differ in the + + align:start position:0% +want to ask how do costs differ in the + + + align:start position:0% +want to ask how do costs differ in the +long run to short run and here there's a + + align:start position:0% +long run to short run and here there's a + + + align:start position:0% +long run to short run and here there's a +relatively simple but important + + align:start position:0% +relatively simple but important + + + align:start position:0% +relatively simple but important +intuition which is that long run + + align:start position:0% +intuition which is that long run + + + align:start position:0% +intuition which is that long run +costs will always + + align:start position:0% +costs will always + + + align:start position:0% +costs will always +be at the lower bound of short run + + align:start position:0% +be at the lower bound of short run + + + align:start position:0% +be at the lower bound of short run +costs the cost of production in Long Run + + align:start position:0% +costs the cost of production in Long Run + + + align:start position:0% +costs the cost of production in Long Run +are always the same or lower than the + + align:start position:0% +are always the same or lower than the + + + align:start position:0% +are always the same or lower than the +cost of production in the short run to + + align:start position:0% +cost of production in the short run to + + + align:start position:0% +cost of production in the short run to +see this let's go to figure 62 this is + + align:start position:0% +see this let's go to figure 62 this is + + + align:start position:0% +see this let's go to figure 62 this is +sort of a hard intuition let's go figure + + align:start position:0% +sort of a hard intuition let's go figure + + + align:start position:0% +sort of a hard intuition let's go figure +62 in this figure there's a firm that + + align:start position:0% +62 in this figure there's a firm that + + + align:start position:0% +62 in this figure there's a firm that +has three possible scales of production + + align:start position:0% +has three possible scales of production + + + align:start position:0% +has three possible scales of production +think of this is three different K bars + + align:start position:0% +think of this is three different K bars + + + align:start position:0% +think of this is three different K bars +they can + + align:start position:0% +they can + + + align:start position:0% +they can +choose and the way production work is in + + align:start position:0% +choose and the way production work is in + + + align:start position:0% +choose and the way production work is in +the short run you choose a k + + align:start position:0% +the short run you choose a k + + + align:start position:0% +the short run you choose a k +bar you then decide how much l to use + + align:start position:0% +bar you then decide how much l to use + + + align:start position:0% +bar you then decide how much l to use +and that's what you produce but in the + + align:start position:0% +and that's what you produce but in the + + + align:start position:0% +and that's what you produce but in the +long run you can change your K bar so + + align:start position:0% +long run you can change your K bar so + + + align:start position:0% +long run you can change your K bar so +think of a firm who has three different + + align:start position:0% +think of a firm who has three different + + + align:start position:0% +think of a firm who has three different +K bar options and those three different + + align:start position:0% +K bar options and those three different + + + align:start position:0% +K bar options and those three different +K bar options give three different + + align:start position:0% +K bar options give three different + + + align:start position:0% +K bar options give three different +average cost curves because you can see + + align:start position:0% +average cost curves because you can see + + + align:start position:0% +average cost curves because you can see +if I change K bar from one to two my + + align:start position:0% +if I change K bar from one to two my + + + align:start position:0% +if I change K bar from one to two my +average cost would change my average + + align:start position:0% +average cost would change my average + + + align:start position:0% +average cost would change my average +cost would no longer + + align:start position:0% +cost would no longer + + + align:start position:0% +cost would no longer +be uh would no longer be 10 over Q + 5 q + + align:start position:0% +be uh would no longer be 10 over Q + 5 q + + + align:start position:0% +be uh would no longer be 10 over Q + 5 q +okay my average cost would be 20 over Q + + align:start position:0% +okay my average cost would be 20 over Q + + + align:start position:0% +okay my average cost would be 20 over Q ++ 5 q okay if Kar changed so think of + + align:start position:0% ++ 5 q okay if Kar changed so think of + + + align:start position:0% ++ 5 q okay if Kar changed so think of +these three curves as three different K + + align:start position:0% +these three curves as three different K + + + align:start position:0% +these three curves as three different K +bars now the firm in the short run has + + align:start position:0% +bars now the firm in the short run has + + + align:start position:0% +bars now the firm in the short run has +to choose which one it wants so for + + align:start position:0% +to choose which one it wants so for + + + align:start position:0% +to choose which one it wants so for +example + + align:start position:0% +example + + + align:start position:0% +example +sr1 that short run AC cost curve one + + align:start position:0% +sr1 that short run AC cost curve one + + + align:start position:0% +sr1 that short run AC cost curve one +that would be the average cost curve + + align:start position:0% +that would be the average cost curve + + + align:start position:0% +that would be the average cost curve +they choose if they think they're not + + align:start position:0% +they choose if they think they're not + + + align:start position:0% +they choose if they think they're not +going to produce that much they think + + align:start position:0% +going to produce that much they think + + + align:start position:0% +going to produce that much they think +they don't have much demand for their + + align:start position:0% +they don't have much demand for their + + + align:start position:0% +they don't have much demand for their +good as opposed to src3 that's the cost + + align:start position:0% +good as opposed to src3 that's the cost + + + align:start position:0% +good as opposed to src3 that's the cost +curve they choose they think there's + + align:start position:0% +curve they choose they think there's + + + align:start position:0% +curve they choose they think there's +going to be a lot of production they + + align:start position:0% +going to be a lot of production they + + + align:start position:0% +going to be a lot of production they +think there going be a lot of demand for + + align:start position:0% +think there going be a lot of demand for + + + align:start position:0% +think there going be a lot of demand for +the good so think of this about how big + + align:start position:0% +the good so think of this about how big + + + align:start position:0% +the good so think of this about how big +you build the plant if you think people + + align:start position:0% +you build the plant if you think people + + + align:start position:0% +you build the plant if you think people +are going to want much of your good you + + align:start position:0% +are going to want much of your good you + + + align:start position:0% +are going to want much of your good you +build a small plant think they're going + + align:start position:0% +build a small plant think they're going + + + align:start position:0% +build a small plant think they're going +want want to want want a lot of your + + align:start position:0% +want want to want want a lot of your + + + align:start position:0% +want want to want want a lot of your +good you build a big plant and sr2 is in + + align:start position:0% +good you build a big plant and sr2 is in + + + align:start position:0% +good you build a big plant and sr2 is in +between okay so in other words if the + + align:start position:0% +between okay so in other words if the + + + align:start position:0% +between okay so in other words if the +firm wants to produce the amount little + + align:start position:0% +firm wants to produce the amount little + + + align:start position:0% +firm wants to produce the amount little +q1 the most efficient K Bar to choose is + + align:start position:0% +q1 the most efficient K Bar to choose is + + + align:start position:0% +q1 the most efficient K Bar to choose is +the K Bar that yields + + align:start position:0% +the K Bar that yields + + + align:start position:0% +the K Bar that yields +sr1 right if the firm wants to produce + + align:start position:0% +sr1 right if the firm wants to produce + + + align:start position:0% +sr1 right if the firm wants to produce +little Q Q3 the most + + align:start position:0% +little Q Q3 the most + + + align:start position:0% +little Q Q3 the most +efficient K Bar to choose is the K Bar + + align:start position:0% +efficient K Bar to choose is the K Bar + + + align:start position:0% +efficient K Bar to choose is the K Bar +that yields + + align:start position:0% +that yields + + + align:start position:0% +that yields +sr3 but in the long run no matter what + + align:start position:0% +sr3 but in the long run no matter what + + + align:start position:0% +sr3 but in the long run no matter what +since it can reoptimize over K it can + + align:start position:0% +since it can reoptimize over K it can + + + align:start position:0% +since it can reoptimize over K it can +always do better than the short run it + + align:start position:0% +always do better than the short run it + + + align:start position:0% +always do better than the short run it +could do or at least no worse so if it + + align:start position:0% +could do or at least no worse so if it + + + align:start position:0% +could do or at least no worse so if it +turns out that in the long run demand is + + align:start position:0% +turns out that in the long run demand is + + + align:start position:0% +turns out that in the long run demand is +q1 and you chose src1 great the long run + + align:start position:0% +q1 and you chose src1 great the long run + + + align:start position:0% +q1 and you chose src1 great the long run +cost is the same as a short run costs + + align:start position:0% +cost is the same as a short run costs + + + align:start position:0% +cost is the same as a short run costs +but if by mistake you chose + + align:start position:0% +but if by mistake you chose + + + align:start position:0% +but if by mistake you chose +sr3 you can do better in the long run by + + align:start position:0% +sr3 you can do better in the long run by + + + align:start position:0% +sr3 you can do better in the long run by +reoptimizing your Capital it's just like + + align:start position:0% +reoptimizing your Capital it's just like + + + align:start position:0% +reoptimizing your Capital it's just like +any general scientific rule the more + + align:start position:0% +any general scientific rule the more + + + align:start position:0% +any general scientific rule the more +variables you have to toy with the more + + align:start position:0% +variables you have to toy with the more + + + align:start position:0% +variables you have to toy with the more +you can optimize okay here you can toy + + align:start position:0% +you can optimize okay here you can toy + + + align:start position:0% +you can optimize okay here you can toy +with two variables labor and capital so + + align:start position:0% +with two variables labor and capital so + + + align:start position:0% +with two variables labor and capital so +you can do better in terms of minimizing + + align:start position:0% +you can do better in terms of minimizing + + + align:start position:0% +you can do better in terms of minimizing +costs this is is not just a theoretical + + align:start position:0% +costs this is is not just a theoretical + + + align:start position:0% +costs this is is not just a theoretical +concept let's talk about one of the most + + align:start position:0% +concept let's talk about one of the most + + + align:start position:0% +concept let's talk about one of the most +important uh companies in America today + + align:start position:0% +important uh companies in America today + + + align:start position:0% +important uh companies in America today +which is + + align:start position:0% +which is + + + align:start position:0% +which is +Tesla when Tesla was founded in + + align:start position:0% +Tesla when Tesla was founded in + + + align:start position:0% +Tesla when Tesla was founded in +2013 Elon Musk had to decide how large a + + align:start position:0% +2013 Elon Musk had to decide how large a + + + align:start position:0% +2013 Elon Musk had to decide how large a +battery production plant to + + align:start position:0% +battery production plant to + + + align:start position:0% +battery production plant to +build he built a plant which was the + + align:start position:0% +build he built a plant which was the + + + align:start position:0% +build he built a plant which was the +size such that he would sell 20,000 cars + + align:start position:0% +size such that he would sell 20,000 cars + + + align:start position:0% +size such that he would sell 20,000 cars +in 2017 he figured his demand be 20,000 + + align:start position:0% +in 2017 he figured his demand be 20,000 + + + align:start position:0% +in 2017 he figured his demand be 20,000 +cars in 2017 so he buil a plant let's + + align:start position:0% +cars in 2017 so he buil a plant let's + + + align:start position:0% +cars in 2017 so he buil a plant let's +call src1 cuz he expect Ed Q little + + align:start position:0% +call src1 cuz he expect Ed Q little + + + align:start position:0% +call src1 cuz he expect Ed Q little +1 what happened was he got Q Little + + align:start position:0% +1 what happened was he got Q Little + + + align:start position:0% +1 what happened was he got Q Little +3 by 2017 there was a 200,000 200,000 + + align:start position:0% +3 by 2017 there was a 200,000 200,000 + + + align:start position:0% +3 by 2017 there was a 200,000 200,000 +person waiting list for Teslas because + + align:start position:0% +person waiting list for Teslas because + + + align:start position:0% +person waiting list for Teslas because +they couldn't produce the batteries fast + + align:start position:0% +they couldn't produce the batteries fast + + + align:start position:0% +they couldn't produce the batteries fast +enough so Elon Musk realized he'd built + + align:start position:0% +enough so Elon Musk realized he'd built + + + align:start position:0% +enough so Elon Musk realized he'd built +too small a plant so he then has built + + align:start position:0% +too small a plant so he then has built + + + align:start position:0% +too small a plant so he then has built +the largest electric battery plant in + + align:start position:0% +the largest electric battery plant in + + + align:start position:0% +the largest electric battery plant in +the world in Nevada he's gone from src1 + + align:start position:0% +the world in Nevada he's gone from src1 + + + align:start position:0% +the world in Nevada he's gone from src1 +to + + align:start position:0% +to + + + align:start position:0% +to +src3 this clant can produce 500,000 cars + + align:start position:0% +src3 this clant can produce 500,000 cars + + + align:start position:0% +src3 this clant can produce 500,000 cars +a year + + align:start position:0% +a year + + + align:start position:0% +a year +but what if people decide Elon Musk is + + align:start position:0% +but what if people decide Elon Musk is + + + align:start position:0% +but what if people decide Elon Musk is +an idiot and they don't want to buy + + align:start position:0% +an idiot and they don't want to buy + + + align:start position:0% +an idiot and they don't want to buy +Teslas anymore okay and all of a sudden + + align:start position:0% +Teslas anymore okay and all of a sudden + + + align:start position:0% +Teslas anymore okay and all of a sudden +Tesla sales Fall well that one could be + + align:start position:0% +Tesla sales Fall well that one could be + + + align:start position:0% +Tesla sales Fall well that one could be +too big and maybe next time he'll sell + + align:start position:0% +too big and maybe next time he'll sell + + + align:start position:0% +too big and maybe next time he'll sell +that plant and build one in + + align:start position:0% +that plant and build one in + + + align:start position:0% +that plant and build one in +between the point is he can always + + align:start position:0% +between the point is he can always + + + align:start position:0% +between the point is he can always +reoptimize depending on how demand turns + + align:start position:0% +reoptimize depending on how demand turns + + + align:start position:0% +reoptimize depending on how demand turns +out to be so you can always do better + + align:start position:0% +out to be so you can always do better + + + align:start position:0% +out to be so you can always do better +Elon Musk did not produce most + + align:start position:0% +Elon Musk did not produce most + + + align:start position:0% +Elon Musk did not produce most +efficiently in the short run so he built + + align:start position:0% +efficiently in the short run so he built + + + align:start position:0% +efficiently in the short run so he built +a bigger plant will he now produce most + + align:start position:0% +a bigger plant will he now produce most + + + align:start position:0% +a bigger plant will he now produce most +efficiently it depends when the demands + + align:start position:0% +efficiently it depends when the demands + + + align:start position:0% +efficiently it depends when the demands +set up a Q3 or somewhere else + + align:start position:0% +set up a Q3 or somewhere else + + + align:start position:0% +set up a Q3 or somewhere else +okay questions about + + align:start position:0% +okay questions about + + + align:start position:0% +okay questions about +that so basically the point is in the + + align:start position:0% +that so basically the point is in the + + + align:start position:0% +that so basically the point is in the +long run it's just like the short run + + align:start position:0% +long run it's just like the short run + + + align:start position:0% +long run it's just like the short run +except you get to choose K bar which + + align:start position:0% +except you get to choose K bar which + + + align:start position:0% +except you get to choose K bar which +means you take multiple shots at what + + align:start position:0% +means you take multiple shots at what + + + align:start position:0% +means you take multiple shots at what +average but having chosen K Bar you're + + align:start position:0% +average but having chosen K Bar you're + + + align:start position:0% +average but having chosen K Bar you're +back in the short run all you can do is + + align:start position:0% +back in the short run all you can do is + + + align:start position:0% +back in the short run all you can do is +value the number of + + align:start position:0% +value the number of + + + align:start position:0% +value the number of +workers okay so think of the long run is + + align:start position:0% +workers okay so think of the long run is + + + align:start position:0% +workers okay so think of the long run is +a set of Short Run games in the each + + align:start position:0% +a set of Short Run games in the each + + + align:start position:0% +a set of Short Run games in the each +short run you choose K Bar you produce + + align:start position:0% +short run you choose K Bar you produce + + + align:start position:0% +short run you choose K Bar you produce +as efficiently as + + align:start position:0% +as efficiently as + + + align:start position:0% +as efficiently as +possible okay if if you turns out you've + + align:start position:0% +possible okay if if you turns out you've + + + align:start position:0% +possible okay if if you turns out you've +chosen the wrong K Bar you then choose a + + align:start position:0% +chosen the wrong K Bar you then choose a + + + align:start position:0% +chosen the wrong K Bar you then choose a +different on the next period the next + + align:start position:0% +different on the next period the next + + + align:start position:0% +different on the next period the next +long run + + align:start position:0% +long run + + + align:start position:0% +long run +period + + align:start position:0% +period + + + align:start position:0% +period +okay so now let's talk about long run + + align:start position:0% + + + + align:start position:0% + +costs let's talk about how we think + + align:start position:0% +costs let's talk about how we think + + + align:start position:0% +costs let's talk about how we think +about firm production decisions and + + align:start position:0% +about firm production decisions and + + + align:start position:0% +about firm production decisions and +costs in a world where both labor and + + align:start position:0% +costs in a world where both labor and + + + align:start position:0% +costs in a world where both labor and +capital is + + align:start position:0% +capital is + + + align:start position:0% +capital is +variable okay so remember last time we + + align:start position:0% +variable okay so remember last time we + + + align:start position:0% +variable okay so remember last time we +developed an ISO + + align:start position:0% +developed an ISO + + + align:start position:0% +developed an ISO +Quant the isoquant was the choice of all + + align:start position:0% +Quant the isoquant was the choice of all + + + align:start position:0% +Quant the isoquant was the choice of all +L and K that give the same same little + + align:start position:0% +L and K that give the same same little + + + align:start position:0% +L and K that give the same same little +Q the choice of all L and K that give + + align:start position:0% +Q the choice of all L and K that give + + + align:start position:0% +Q the choice of all L and K that give +the same little Q was the + + align:start position:0% +the same little Q was the + + + align:start position:0% +the same little Q was the +isoquant and you could + + align:start position:0% +isoquant and you could + + + align:start position:0% +isoquant and you could +choose um and basically the point was + + align:start position:0% +choose um and basically the point was + + + align:start position:0% +choose um and basically the point was +along any given isoquant there are + + align:start position:0% +along any given isoquant there are + + + align:start position:0% +along any given isoquant there are +different combinations of L and K that + + align:start position:0% +different combinations of L and K that + + + align:start position:0% +different combinations of L and K that +can give you a little Q just like along + + align:start position:0% +can give you a little Q just like along + + + align:start position:0% +can give you a little Q just like along +an ISO just along an indifference curve + + align:start position:0% +an ISO just along an indifference curve + + + align:start position:0% +an ISO just along an indifference curve +there are many combinations of pizza and + + align:start position:0% +there are many combinations of pizza and + + + align:start position:0% +there are many combinations of pizza and +cookies that make you equally happy so + + align:start position:0% +cookies that make you equally happy so + + + align:start position:0% +cookies that make you equally happy so +the question is how do you decide which + + align:start position:0% +the question is how do you decide which + + + align:start position:0% +the question is how do you decide which +combination to use well to do so + + align:start position:0% +combination to use well to do so + + + align:start position:0% +combination to use well to do so +we create just like in consumer Theory + + align:start position:0% +we create just like in consumer Theory + + + align:start position:0% +we create just like in consumer Theory +we solve the problem by creating a + + align:start position:0% +we solve the problem by creating a + + + align:start position:0% +we solve the problem by creating a +budget constraint in producer Theory we + + align:start position:0% +budget constraint in producer Theory we + + + align:start position:0% +budget constraint in producer Theory we +solve the problem by creating an ISO + + align:start position:0% +solve the problem by creating an ISO + + + align:start position:0% +solve the problem by creating an ISO +cost + + align:start position:0% +cost + + + align:start position:0% +cost +line the iso cost line which is + + align:start position:0% +line the iso cost line which is + + + align:start position:0% +line the iso cost line which is +basically the firm's budget constraint + + align:start position:0% +basically the firm's budget constraint + + + align:start position:0% +basically the firm's budget constraint +if you will isoc cost line is the line + + align:start position:0% +if you will isoc cost line is the line + + + align:start position:0% +if you will isoc cost line is the line +which gives you the cost of Labor and + + align:start position:0% +which gives you the cost of Labor and + + + align:start position:0% +which gives you the cost of Labor and +capital uh that help you choose which + + align:start position:0% +capital uh that help you choose which + + + align:start position:0% +capital uh that help you choose which +combination you'd like to choose so I'm + + align:start position:0% +combination you'd like to choose so I'm + + + align:start position:0% +combination you'd like to choose so I'm +not saying it well in words let's go to + + align:start position:0% +not saying it well in words let's go to + + + align:start position:0% +not saying it well in words let's go to +the graphs okay here's some isocost + + align:start position:0% +the graphs okay here's some isocost + + + align:start position:0% +the graphs okay here's some isocost +lines remember I assumed that the wage + + align:start position:0% +lines remember I assumed that the wage + + + align:start position:0% +lines remember I assumed that the wage +was five and the renovated Capital was + + align:start position:0% +was five and the renovated Capital was + + + align:start position:0% +was five and the renovated Capital was +10 okay so basically these lines are + + align:start position:0% +10 okay so basically these lines are + + + align:start position:0% +10 okay so basically these lines are +combinations of capital and labor that + + align:start position:0% +combinations of capital and labor that + + + align:start position:0% +combinations of capital and labor that +yield the same total level of costs the + + align:start position:0% +yield the same total level of costs the + + + align:start position:0% +yield the same total level of costs the +combination of capital and labor that + + align:start position:0% +combination of capital and labor that + + + align:start position:0% +combination of capital and labor that +yield the same total level of costs so + + align:start position:0% +yield the same total level of costs so + + + align:start position:0% +yield the same total level of costs so +you see the $50 Isa cost says if you + + align:start position:0% +you see the $50 Isa cost says if you + + + align:start position:0% +you see the $50 Isa cost says if you +want to spend $50 you could either have + + align:start position:0% +want to spend $50 you could either have + + + align:start position:0% +want to spend $50 you could either have +10 units of Labor + + align:start position:0% +10 units of Labor + + + align:start position:0% +10 units of Labor +and no Capital five units of capital and + + align:start position:0% +and no Capital five units of capital and + + + align:start position:0% +and no Capital five units of capital and +no labor some combination in + + align:start position:0% +no labor some combination in + + + align:start position:0% +no labor some combination in +between but if you want to spend + + align:start position:0% +between but if you want to spend + + + align:start position:0% +between but if you want to spend +$150 you could then have 30 units of + + align:start position:0% +$150 you could then have 30 units of + + + align:start position:0% +$150 you could then have 30 units of +Labor and no capital or 15 units of + + align:start position:0% +Labor and no capital or 15 units of + + + align:start position:0% +Labor and no capital or 15 units of +capital no labor or some combination in + + align:start position:0% +capital no labor or some combination in + + + align:start position:0% +capital no labor or some combination in +between so it's basically the + + align:start position:0% +between so it's basically the + + + align:start position:0% +between so it's basically the +combination of capital and labor that + + align:start position:0% +combination of capital and labor that + + + align:start position:0% +combination of capital and labor that +yield the same total + + align:start position:0% +yield the same total + + + align:start position:0% +yield the same total +cost okay and what is the slope of the + + align:start position:0% +cost okay and what is the slope of the + + + align:start position:0% +cost okay and what is the slope of the +isocost line well the slope is minus W + + align:start position:0% +isocost line well the slope is minus W + + + align:start position:0% +isocost line well the slope is minus W +over + + align:start position:0% +over + + + align:start position:0% +over +R minus the ratio of the price of Labor + + align:start position:0% +R minus the ratio of the price of Labor + + + align:start position:0% +R minus the ratio of the price of Labor +to the price of + + align:start position:0% +to the price of + + + align:start position:0% +to the price of +capital okay what does this say this + + align:start position:0% +capital okay what does this say this + + + align:start position:0% +capital okay what does this say this +says that you have to give up half a + + align:start position:0% +says that you have to give up half a + + + align:start position:0% +says that you have to give up half a +unit of capital to get a unit of Labor + + align:start position:0% +unit of capital to get a unit of Labor + + + align:start position:0% +unit of capital to get a unit of Labor +it's back to opportunity costs for a + + align:start position:0% +it's back to opportunity costs for a + + + align:start position:0% +it's back to opportunity costs for a +given total cost of production if you + + align:start position:0% +given total cost of production if you + + + align:start position:0% +given total cost of production if you +want one more worker you're gonna have + + align:start position:0% +want one more worker you're gonna have + + + align:start position:0% +want one more worker you're gonna have +to give up half a + + align:start position:0% +to give up half a + + + align:start position:0% +to give up half a +machine okay for a given total cost of + + align:start position:0% +machine okay for a given total cost of + + + align:start position:0% +machine okay for a given total cost of +Productions that's the slope of the + + align:start position:0% +Productions that's the slope of the + + + align:start position:0% +Productions that's the slope of the +isocost line so then we say the firm to + + align:start position:0% +isocost line so then we say the firm to + + + align:start position:0% +isocost line so then we say the firm to +minimize + + align:start position:0% +minimize + + + align:start position:0% +minimize +costs will use the efficient + + align:start position:0% +costs will use the efficient + + + align:start position:0% +costs will use the efficient +combination of Labor and capital to + + align:start position:0% +combination of Labor and capital to + + + align:start position:0% +combination of Labor and capital to +produce any level of goods and how do we + + align:start position:0% +produce any level of goods and how do we + + + align:start position:0% +produce any level of goods and how do we +get that we get that by the tangency + + align:start position:0% +get that we get that by the tangency + + + align:start position:0% +get that we get that by the tangency +between the isoquant and the iso cost + + align:start position:0% +between the isoquant and the iso cost + + + align:start position:0% +between the isoquant and the iso cost +the tangency between the iso Quant and + + align:start position:0% +the tangency between the iso Quant and + + + align:start position:0% +the tangency between the iso Quant and +the iso cost gives us the efficient + + align:start position:0% +the iso cost gives us the efficient + + + align:start position:0% +the iso cost gives us the efficient +combination of capital and labor for any + + align:start position:0% +combination of capital and labor for any + + + align:start position:0% +combination of capital and labor for any +level of production little Q so so for + + align:start position:0% +level of production little Q so so for + + + align:start position:0% +level of production little Q so so for +example going back keeping these isocost + + align:start position:0% +example going back keeping these isocost + + + align:start position:0% +example going back keeping these isocost +lines and going back to our production + + align:start position:0% +lines and going back to our production + + + align:start position:0% +lines and going back to our production +function and our therefore cost + + align:start position:0% +function and our therefore cost + + + align:start position:0% +function and our therefore cost +function we can draw the + + align:start position:0% +function we can draw the + + + align:start position:0% +function we can draw the +isoquant okay uh for production okay so + + align:start position:0% +isoquant okay uh for production okay so + + + align:start position:0% +isoquant okay uh for production okay so +we start with the production function we + + align:start position:0% +we start with the production function we + + + align:start position:0% +we start with the production function we +start with our production function qal + + align:start position:0% +start with our production function qal + + + align:start position:0% +start with our production function qal +of L * K okay we know that the slope of + + align:start position:0% +of L * K okay we know that the slope of + + + align:start position:0% +of L * K okay we know that the slope of +the isoquant the isoquant slope we + + align:start position:0% +the isoquant the isoquant slope we + + + align:start position:0% +the isoquant the isoquant slope we +defined last time is minus MP L over + + align:start position:0% +defined last time is minus MP L over + + + align:start position:0% +defined last time is minus MP L over +mpk MPL over + + align:start position:0% +mpk MPL over + + + align:start position:0% +mpk MPL over +mpk so at the tangency we set these two + + align:start position:0% +mpk so at the tangency we set these two + + + align:start position:0% +mpk so at the tangency we set these two +things + + align:start position:0% +things + + + align:start position:0% +things +equal we set npl over mpk equal to W + + align:start position:0% +equal we set npl over mpk equal to W + + + align:start position:0% +equal we set npl over mpk equal to W +over + + align:start position:0% +over + + + align:start position:0% +over +r that is in the optimum with this + + align:start position:0% +r that is in the optimum with this + + + align:start position:0% +r that is in the optimum with this +example okay you set these things equal + + align:start position:0% +example okay you set these things equal + + + align:start position:0% +example okay you set these things equal +you you always set the slope of the + + align:start position:0% +you you always set the slope of the + + + align:start position:0% +you you always set the slope of the +isocost line equal to slope of the + + align:start position:0% +isocost line equal to slope of the + + + align:start position:0% +isocost line equal to slope of the +isoquant but in this example that is + + align:start position:0% +isoquant but in this example that is + + + align:start position:0% +isoquant but in this example that is +such that you want to use half as much + + align:start position:0% +such that you want to use half as much + + + align:start position:0% +such that you want to use half as much +Capital as labor you want to basically + + align:start position:0% +Capital as labor you want to basically + + + align:start position:0% +Capital as labor you want to basically +use because basically if you look at um + + align:start position:0% +use because basically if you look at um + + + align:start position:0% +use because basically if you look at um +MPL if you use our example we defined + + align:start position:0% +MPL if you use our example we defined + + + align:start position:0% +MPL if you use our example we defined +last time set these equal says remember + + align:start position:0% +last time set these equal says remember + + + align:start position:0% +last time set these equal says remember +from last time the MPL was minus L over + + align:start position:0% +from last time the MPL was minus L over + + + align:start position:0% +from last time the MPL was minus L over +K here we're saying to equal to minus W + + align:start position:0% +K here we're saying to equal to minus W + + + align:start position:0% +K here we're saying to equal to minus W +over R okay if you remember last time we + + align:start position:0% +over R okay if you remember last time we + + + align:start position:0% +over R okay if you remember last time we +solved for the marginal the mrts I'm + + align:start position:0% +solved for the marginal the mrts I'm + + + align:start position:0% +solved for the marginal the mrts I'm +sorry K Over + + align:start position:0% +sorry K Over + + + align:start position:0% +sorry K Over +l k over + + align:start position:0% +l k over + + + align:start position:0% +l k over +l k over l so minus k lus w Rus k l we + + align:start position:0% +l k over l so minus k lus w Rus k l we + + + align:start position:0% +l k over l so minus k lus w Rus k l we +defined last time as the marginal rate + + align:start position:0% +defined last time as the marginal rate + + + align:start position:0% +defined last time as the marginal rate +of technical + + align:start position:0% + + + + align:start position:0% + +substitution okay which is generally + + align:start position:0% +substitution okay which is generally + + + align:start position:0% +substitution okay which is generally +this formula but in our specific case + + align:start position:0% +this formula but in our specific case + + + align:start position:0% +this formula but in our specific case +it's that minus WR is the price ratio + + align:start position:0% +it's that minus WR is the price ratio + + + align:start position:0% +it's that minus WR is the price ratio +the the margin rate of technical + + align:start position:0% +the the margin rate of technical + + + align:start position:0% +the the margin rate of technical +substitution is the slope of the + + align:start position:0% +substitution is the slope of the + + + align:start position:0% +substitution is the slope of the +isoquant minus W over R is the slope of + + align:start position:0% +isoquant minus W over R is the slope of + + + align:start position:0% +isoquant minus W over R is the slope of +the price ratio here in our example + + align:start position:0% +the price ratio here in our example + + + align:start position:0% +the price ratio here in our example +example we know that equals minus a half + + align:start position:0% +example we know that equals minus a half + + + align:start position:0% +example we know that equals minus a half +so in this example you want to set K L + + align:start position:0% +so in this example you want to set K L + + + align:start position:0% +so in this example you want to set K L +equal to minus a half you want half as + + align:start position:0% +equal to minus a half you want half as + + + align:start position:0% +equal to minus a half you want half as +much Capital as + + align:start position:0% +much Capital as + + + align:start position:0% +much Capital as +labor okay why is that well same + + align:start position:0% +labor okay why is that well same + + + align:start position:0% +labor okay why is that well same +intuitions with + + align:start position:0% +intuitions with + + + align:start position:0% +intuitions with +consumers okay you can the market is + + align:start position:0% +consumers okay you can the market is + + + align:start position:0% +consumers okay you can the market is +telling you it's going to cost half as + + align:start position:0% +telling you it's going to cost half as + + + align:start position:0% +telling you it's going to cost half as +much to have a worker as a + + align:start position:0% +much to have a worker as a + + + align:start position:0% +much to have a worker as a +machine your technology is telling you + + align:start position:0% + + + + align:start position:0% + +okay that you are you're basically + + align:start position:0% +okay that you are you're basically + + + align:start position:0% +okay that you are you're basically +indifferent that basically you at the + + align:start position:0% +indifferent that basically you at the + + + align:start position:0% +indifferent that basically you at the +point you're at you are um you're + + align:start position:0% +point you're at you are um you're + + + align:start position:0% +point you're at you are um you're +basically the tradeoff between workers + + align:start position:0% +basically the tradeoff between workers + + + align:start position:0% +basically the tradeoff between workers +and machines is K Over l so you set + + align:start position:0% +and machines is K Over l so you set + + + align:start position:0% +and machines is K Over l so you set +those equal and that gives you the rule + + align:start position:0% +those equal and that gives you the rule + + + align:start position:0% +those equal and that gives you the rule +that you want to set in our particular + + align:start position:0% +that you want to set in our particular + + + align:start position:0% +that you want to set in our particular +example K Over L equal to minus W over2 + + align:start position:0% +example K Over L equal to minus W over2 + + + align:start position:0% +example K Over L equal to minus W over2 +so let me review again a the isoquant + + align:start position:0% +so let me review again a the isoquant + + + align:start position:0% +so let me review again a the isoquant +Curve comes from production function and + + align:start position:0% +Curve comes from production function and + + + align:start position:0% +Curve comes from production function and +delivers the marginal rate of technical + + align:start position:0% +delivers the marginal rate of technical + + + align:start position:0% +delivers the marginal rate of technical +substitution which is this step one okay + + align:start position:0% +substitution which is this step one okay + + + align:start position:0% +substitution which is this step one okay +step two the iso cost has a slope of + + align:start position:0% +step two the iso cost has a slope of + + + align:start position:0% +step two the iso cost has a slope of +this step three you set them equal so + + align:start position:0% +this step three you set them equal so + + + align:start position:0% +this step three you set them equal so +you get minus K Over L which is what + + align:start position:0% +you get minus K Over L which is what + + + align:start position:0% +you get minus K Over L which is what +this is equals minus a half which is + + align:start position:0% +this is equals minus a half which is + + + align:start position:0% +this is equals minus a half which is +what that is so use capital and labor + + align:start position:0% +what that is so use capital and labor + + + align:start position:0% +what that is so use capital and labor +until using half as much Capital as + + align:start position:0% +until using half as much Capital as + + + align:start position:0% +until using half as much Capital as +labor and once again you can use the + + align:start position:0% +labor and once again you can use the + + + align:start position:0% +labor and once again you can use the +same kind of examples we use for + + align:start position:0% +same kind of examples we use for + + + align:start position:0% +same kind of examples we use for +Consumer Theory to show you why if you + + align:start position:0% +Consumer Theory to show you why if you + + + align:start position:0% +Consumer Theory to show you why if you +weren't using half as much Capital as + + align:start position:0% +weren't using half as much Capital as + + + align:start position:0% +weren't using half as much Capital as +labor you'd be getting it wrong should s + + align:start position:0% +labor you'd be getting it wrong should s + + + align:start position:0% +labor you'd be getting it wrong should s +yourself at home remember last time we + + align:start position:0% +yourself at home remember last time we + + + align:start position:0% +yourself at home remember last time we +had points on we had points where the + + align:start position:0% +had points on we had points where the + + + align:start position:0% +had points on we had points where the +where the indifference curve wasn't + + align:start position:0% +where the indifference curve wasn't + + + align:start position:0% +where the indifference curve wasn't +tangent to the budget constraint we show + + align:start position:0% +tangent to the budget constraint we show + + + align:start position:0% +tangent to the budget constraint we show +why they were wrong you can do the same + + align:start position:0% +why they were wrong you can do the same + + + align:start position:0% +why they were wrong you can do the same +thing here you can draw points where the + + align:start position:0% +thing here you can draw points where the + + + align:start position:0% +thing here you can draw points where the +isoquant is not tangent to the isocost + + align:start position:0% +isoquant is not tangent to the isocost + + + align:start position:0% +isoquant is not tangent to the isocost +and show you why that's inefficient why + + align:start position:0% +and show you why that's inefficient why + + + align:start position:0% +and show you why that's inefficient why +it's inefficient + + align:start position:0% +it's inefficient + + + align:start position:0% +it's inefficient +production okay now questions about + + align:start position:0% +production okay now questions about + + + align:start position:0% +production okay now questions about +that + + align:start position:0% + + + + align:start position:0% + +yeah oh that's a okay oh Jesus that's + + align:start position:0% +yeah oh that's a okay oh Jesus that's + + + align:start position:0% +yeah oh that's a okay oh Jesus that's +that the uh let me make sure I I get the + + align:start position:0% +that the uh let me make sure I I get the + + + align:start position:0% +that the uh let me make sure I I get the +uh get the inversion right it's + + align:start position:0% +uh get the inversion right it's + + + align:start position:0% +uh get the inversion right it's +MPL over mpk sorry about that that's not + + align:start position:0% +MPL over mpk sorry about that that's not + + + align:start position:0% +MPL over mpk sorry about that that's not +any better mpk MPL mpk thank you for + + align:start position:0% +any better mpk MPL mpk thank you for + + + align:start position:0% +any better mpk MPL mpk thank you for +asking once again 70% of the class had + + align:start position:0% +asking once again 70% of the class had + + + align:start position:0% +asking once again 70% of the class had +no idea what those were so you did a + + align:start position:0% +no idea what those were so you did a + + + align:start position:0% +no idea what those were so you did a +good service yeah go + + align:start position:0% + + + + align:start position:0% + +ahead for this example yes the general + + align:start position:0% +ahead for this example yes the general + + + align:start position:0% +ahead for this example yes the general +formula is that the mrts equal to the + + align:start position:0% +formula is that the mrts equal to the + + + align:start position:0% +formula is that the mrts equal to the +input price ratio + + align:start position:0% + + + + align:start position:0% + +that's the general formula so general + + align:start position:0% +that's the general formula so general + + + align:start position:0% +that's the general formula so general +formula is you set minus m + + align:start position:0% +formula is you set minus m + + + align:start position:0% +formula is you set minus m +l over + + align:start position:0% +l over + + + align:start position:0% +l over +mpk equal to minus W over R that's the + + align:start position:0% +mpk equal to minus W over R that's the + + + align:start position:0% +mpk equal to minus W over R that's the +general formula in our particular case + + align:start position:0% +general formula in our particular case + + + align:start position:0% +general formula in our particular case +that amounts to K Over L equals a + + align:start position:0% +that amounts to K Over L equals a + + + align:start position:0% +that amounts to K Over L equals a +half yeah + + align:start position:0% + + + + align:start position:0% + +is there + + align:start position:0% + + + + align:start position:0% + +version that's a really interesting + + align:start position:0% +version that's a really interesting + + + align:start position:0% +version that's a really interesting +question um that we won't really get + + align:start position:0% +question um that we won't really get + + + align:start position:0% +question um that we won't really get +into I think the difference is actually + + align:start position:0% +into I think the difference is actually + + + align:start position:0% +into I think the difference is actually +I will teach you why I won't get into it + + align:start position:0% +I will teach you why I won't get into it + + + align:start position:0% +I will teach you why I won't get into it +because firms you're it's a good segue + + align:start position:0% +because firms you're it's a good segue + + + align:start position:0% +because firms you're it's a good segue +to why firms are not the same as + + align:start position:0% +to why firms are not the same as + + + align:start position:0% +to why firms are not the same as +consumers and I'll talk about that in a + + align:start position:0% +consumers and I'll talk about that in a + + + align:start position:0% +consumers and I'll talk about that in a +minute other questions okay well that's + + align:start position:0% +minute other questions okay well that's + + + align:start position:0% +minute other questions okay well that's +a great segue which is when we did + + align:start position:0% +a great segue which is when we did + + + align:start position:0% +a great segue which is when we did +consumer Theory we were done here we + + align:start position:0% +consumer Theory we were done here we + + + align:start position:0% +consumer Theory we were done here we +said well I just find the point where + + align:start position:0% +said well I just find the point where + + + align:start position:0% +said well I just find the point where +this is true + + align:start position:0% +this is true + + + align:start position:0% +this is true +that's the optimal + + align:start position:0% +that's the optimal + + + align:start position:0% +that's the optimal +bundle then I think comes substitution + + align:start position:0% +bundle then I think comes substitution + + + align:start position:0% +bundle then I think comes substitution +effects and all that as was pointed + + align:start position:0% +effects and all that as was pointed + + + align:start position:0% +effects and all that as was pointed +out this is why producer theory is + + align:start position:0% +out this is why producer theory is + + + align:start position:0% +out this is why producer theory is +harder because we're not done why aren't + + align:start position:0% +harder because we're not done why aren't + + + align:start position:0% +harder because we're not done why aren't +we done because I didn't tell you the + + align:start position:0% +we done because I didn't tell you the + + + align:start position:0% +we done because I didn't tell you the +Right iso + + align:start position:0% +Right iso + + + align:start position:0% +Right iso +cost with per consumer Theory I gave you + + align:start position:0% +cost with per consumer Theory I gave you + + + align:start position:0% +cost with per consumer Theory I gave you +a budget + + align:start position:0% +a budget + + + align:start position:0% +a budget +constraint I'm not giving you an ISO + + align:start position:0% +constraint I'm not giving you an ISO + + + align:start position:0% +constraint I'm not giving you an ISO +cost here I'm just saying there are + + align:start position:0% +cost here I'm just saying there are + + + align:start position:0% +cost here I'm just saying there are +multiple possible ISO costs therefore + + align:start position:0% +multiple possible ISO costs therefore + + + align:start position:0% +multiple possible ISO costs therefore +there are multiple possible + + align:start position:0% +there are multiple possible + + + align:start position:0% +there are multiple possible +tangencies so with consumer Theory I + + align:start position:0% +tangencies so with consumer Theory I + + + align:start position:0% +tangencies so with consumer Theory I +gave you a budget constraint and + + align:start position:0% +gave you a budget constraint and + + + align:start position:0% +gave you a budget constraint and +therefore I told you two equations and + + align:start position:0% +therefore I told you two equations and + + + align:start position:0% +therefore I told you two equations and +two unknowns gives you the answer here + + align:start position:0% +two unknowns gives you the answer here + + + align:start position:0% +two unknowns gives you the answer here +two equations two unknowns does not give + + align:start position:0% +two equations two unknowns does not give + + + align:start position:0% +two equations two unknowns does not give +you the answer it just gives you a + + align:start position:0% +you the answer it just gives you a + + + align:start position:0% +you the answer it just gives you a +formula but how you apply that formula + + align:start position:0% +formula but how you apply that formula + + + align:start position:0% +formula but how you apply that formula +is going to depend on how big you want + + align:start position:0% +is going to depend on how big you want + + + align:start position:0% +is going to depend on how big you want +your firm to be which isocost you want + + align:start position:0% +your firm to be which isocost you want + + + align:start position:0% +your firm to be which isocost you want +to choose well how the hell you going to + + align:start position:0% +to choose well how the hell you going to + + + align:start position:0% +to choose well how the hell you going to +choose that that's where we have to add + + align:start position:0% +choose that that's where we have to add + + + align:start position:0% +choose that that's where we have to add +one more step that's where producer + + align:start position:0% +one more step that's where producer + + + align:start position:0% +one more step that's where producer +Theory gets one step + + align:start position:0% +Theory gets one step + + + align:start position:0% +Theory gets one step +harder to see that let's look at figure + + align:start position:0% + + + + align:start position:0% + +65a figure + + align:start position:0% +65a figure + + + align:start position:0% +65a figure +65a shows for different ISO + + align:start position:0% +65a shows for different ISO + + + align:start position:0% +65a shows for different ISO +cost how much capital and labor we want + + align:start position:0% +cost how much capital and labor we want + + + align:start position:0% +cost how much capital and labor we want +to use for our example so the previous + + align:start position:0% +to use for our example so the previous + + + align:start position:0% +to use for our example so the previous +example we were at Point a we were + + align:start position:0% +example we were at Point a we were + + + align:start position:0% +example we were at Point a we were +choosing to spend + + align:start position:0% +choosing to spend + + + align:start position:0% +choosing to spend +$50 that allowed us to produce square + + align:start position:0% +$50 that allowed us to produce square + + + align:start position:0% +$50 that allowed us to produce square +root of 12.5 + + align:start position:0% +root of 12.5 + + + align:start position:0% +root of 12.5 +units okay at a tangency of five units + + align:start position:0% +units okay at a tangency of five units + + + align:start position:0% +units okay at a tangency of five units +of cap labor and two and a half units of + + align:start position:0% +of cap labor and two and a half units of + + + align:start position:0% +of cap labor and two and a half units of +capital okay flip back and forth to + + align:start position:0% +capital okay flip back and forth to + + + align:start position:0% +capital okay flip back and forth to +figure 64 you'll see that's where we + + align:start position:0% +figure 64 you'll see that's where we + + + align:start position:0% +figure 64 you'll see that's where we +were + + align:start position:0% +were + + + align:start position:0% +were +right however I could have said instead + + align:start position:0% +right however I could have said instead + + + align:start position:0% +right however I could have said instead +no I want to be bigger I want to make + + align:start position:0% +no I want to be bigger I want to make + + + align:start position:0% +no I want to be bigger I want to make +more I'm going to choose to spend 100 + + align:start position:0% +more I'm going to choose to spend 100 + + + align:start position:0% +more I'm going to choose to spend 100 +then I would be at point B where I could + + align:start position:0% +then I would be at point B where I could + + + align:start position:0% +then I would be at point B where I could +have 20 units not 100 square of 50 it's + + align:start position:0% +have 20 units not 100 square of 50 it's + + + align:start position:0% +have 20 units not 100 square of 50 it's +uh four times yeah yeah I'm going to + + align:start position:0% +uh four times yeah yeah I'm going to + + + align:start position:0% +uh four times yeah yeah I'm going to +spend 200 okay so basically here if I + + align:start position:0% +spend 200 okay so basically here if I + + + align:start position:0% +spend 200 okay so basically here if I +spend 200 I can have 20 workers and 10 + + align:start position:0% +spend 200 I can have 20 workers and 10 + + + align:start position:0% +spend 200 I can have 20 workers and 10 +machines I I spend 200 have 20 workers + + align:start position:0% +machines I I spend 200 have 20 workers + + + align:start position:0% +machines I I spend 200 have 20 workers +of 10 machines and then I'll produce + + align:start position:0% +of 10 machines and then I'll produce + + + align:start position:0% +of 10 machines and then I'll produce +square root of 50 which is right I don't + + align:start position:0% +square root of 50 which is right I don't + + + align:start position:0% +square root of 50 which is right I don't +know I haven't told you yet how do you + + align:start position:0% +know I haven't told you yet how do you + + + align:start position:0% +know I haven't told you yet how do you +choose as a boss remember capital's + + align:start position:0% +choose as a boss remember capital's + + + align:start position:0% +choose as a boss remember capital's +fixed I'm talking about this is not the + + align:start position:0% +fixed I'm talking about this is not the + + + align:start position:0% +fixed I'm talking about this is not the +Elon Musk example it's not Capital this + + align:start position:0% +Elon Musk example it's not Capital this + + + align:start position:0% +Elon Musk example it's not Capital this +is within the short run this is how many + + align:start position:0% +is within the short run this is how many + + + align:start position:0% +is within the short run this is how many +workers do you + + align:start position:0% +workers do you + + + align:start position:0% +workers do you +hire well you don't know you could hire + + align:start position:0% +hire well you don't know you could hire + + + align:start position:0% +hire well you don't know you could hire +10 workers 20 workers 30 workers it + + align:start position:0% +10 workers 20 workers 30 workers it + + + align:start position:0% +10 workers 20 workers 30 workers it +depends how much you want to + + align:start position:0% +depends how much you want to + + + align:start position:0% +depends how much you want to +produce how much you want to produce + + align:start position:0% +produce how much you want to produce + + + align:start position:0% +produce how much you want to produce +that is the extra step we have to add + + align:start position:0% +that is the extra step we have to add + + + align:start position:0% +that is the extra step we have to add +for Consumer for producer Theory + + align:start position:0% +for Consumer for producer Theory + + + align:start position:0% +for Consumer for producer Theory +we call this the long run expansion + + align:start position:0% +we call this the long run expansion + + + align:start position:0% +we call this the long run expansion +path this is + + align:start position:0% +path this is + + + align:start position:0% +path this is +essentially the combinations of Labor + + align:start position:0% +essentially the combinations of Labor + + + align:start position:0% +essentially the combinations of Labor +and + + align:start position:0% +and + + + align:start position:0% +and +capital at every single Quee that you + + align:start position:0% +capital at every single Quee that you + + + align:start position:0% +capital at every single Quee that you +would choose in other words you can map + + align:start position:0% +would choose in other words you can map + + + align:start position:0% +would choose in other words you can map +out I haven't yet to told you which + + align:start position:0% +out I haven't yet to told you which + + + align:start position:0% +out I haven't yet to told you which +queue you're going to choose but I've + + align:start position:0% +queue you're going to choose but I've + + + align:start position:0% +queue you're going to choose but I've +told you how to map out for each Q how + + align:start position:0% +told you how to map out for each Q how + + + align:start position:0% +told you how to map out for each Q how +much Ln K you want to + + align:start position:0% +much Ln K you want to + + + align:start position:0% +much Ln K you want to +use if you decide the que you want a + + align:start position:0% +use if you decide the que you want a + + + align:start position:0% +use if you decide the que you want a +square of 12 A2 you choose 10 workers + + align:start position:0% +square of 12 A2 you choose 10 workers + + + align:start position:0% +square of 12 A2 you choose 10 workers +and five machines if you decide it's a + + align:start position:0% +and five machines if you decide it's a + + + align:start position:0% +and five machines if you decide it's a +square 112 A2 you choose 30 workers and + + align:start position:0% +square 112 A2 you choose 30 workers and + + + align:start position:0% +square 112 A2 you choose 30 workers and + + align:start position:0% + + + align:start position:0% +machines ultimately the question is how + + align:start position:0% +machines ultimately the question is how + + + align:start position:0% +machines ultimately the question is how +much you want to + + align:start position:0% +much you want to + + + align:start position:0% +much you want to +produce now in this example the long run + + align:start position:0% +produce now in this example the long run + + + align:start position:0% +produce now in this example the long run +expansion path is linear but it doesn't + + align:start position:0% +expansion path is linear but it doesn't + + + align:start position:0% +expansion path is linear but it doesn't +have to be for example consider figure + + align:start position:0% +have to be for example consider figure + + + align:start position:0% +have to be for example consider figure +65b this is a long run expansion path + + align:start position:0% +65b this is a long run expansion path + + + align:start position:0% +65b this is a long run expansion path +where capital is is becoming less + + align:start position:0% +where capital is is becoming less + + + align:start position:0% +where capital is is becoming less +productive as you produce + + align:start position:0% +productive as you produce + + + align:start position:0% +productive as you produce +more okay in 65a no matter how much you + + align:start position:0% +more okay in 65a no matter how much you + + + align:start position:0% +more okay in 65a no matter how much you +produce you always want to use half as + + align:start position:0% +produce you always want to use half as + + + align:start position:0% +produce you always want to use half as +much Capital as labor that ratio never + + align:start position:0% +much Capital as labor that ratio never + + + align:start position:0% +much Capital as labor that ratio never +changes in 65b it does change that means + + align:start position:0% +changes in 65b it does change that means + + + align:start position:0% +changes in 65b it does change that means +it's a different production + + align:start position:0% +it's a different production + + + align:start position:0% +it's a different production +function I haven't written down the + + align:start position:0% +function I haven't written down the + + + align:start position:0% +function I haven't written down the +underlying production function for 65b + + align:start position:0% +underlying production function for 65b + + + align:start position:0% +underlying production function for 65b +but it's a different production function + + align:start position:0% +but it's a different production function + + + align:start position:0% +but it's a different production function +the iso costs are the same the cost of + + align:start position:0% +the iso costs are the same the cost of + + + align:start position:0% +the iso costs are the same the cost of +Labor and capital labor is always TW + + align:start position:0% +Labor and capital labor is always TW + + + align:start position:0% +Labor and capital labor is always TW +half the price of capital but it's a + + align:start position:0% +half the price of capital but it's a + + + align:start position:0% +half the price of capital but it's a +different production function which has + + align:start position:0% +different production function which has + + + align:start position:0% +different production function which has +the feature that as you produce more and + + align:start position:0% +the feature that as you produce more and + + + align:start position:0% +the feature that as you produce more and +more Capital becomes less productive you + + align:start position:0% +more Capital becomes less productive you + + + align:start position:0% +more Capital becomes less productive you +might think of this as something like a + + align:start position:0% +might think of this as something like a + + + align:start position:0% +might think of this as something like a +McDonald's long run expansion path once + + align:start position:0% +McDonald's long run expansion path once + + + align:start position:0% +McDonald's long run expansion path once +they' got the fryolator and the + + align:start position:0% +they' got the fryolator and the + + + align:start position:0% +they' got the fryolator and the +building then what really matters is how + + align:start position:0% +building then what really matters is how + + + align:start position:0% +building then what really matters is how +many more workers you have you employ + + align:start position:0% +many more workers you have you employ + + + align:start position:0% +many more workers you have you employ +there cranking stuff through so that's a + + align:start position:0% +there cranking stuff through so that's a + + + align:start position:0% +there cranking stuff through so that's a +case where in some sense each additional + + align:start position:0% +case where in some sense each additional + + + align:start position:0% +case where in some sense each additional +unit of capital the fry later isn't that + + align:start position:0% +unit of capital the fry later isn't that + + + align:start position:0% +unit of capital the fry later isn't that +productive okay it's really labor which + + align:start position:0% +productive okay it's really labor which + + + align:start position:0% +productive okay it's really labor which +is really the thing which you want more + + align:start position:0% +is really the thing which you want more + + + align:start position:0% +is really the thing which you want more +and more of as you + + align:start position:0% +and more of as you + + + align:start position:0% +and more of as you +expand alternatively you could have + + align:start position:0% +expand alternatively you could have + + + align:start position:0% +expand alternatively you could have +something like figure 65 + + align:start position:0% +something like figure 65 + + + align:start position:0% +something like figure 65 +C which is an expansion path where + + align:start position:0% +C which is an expansion path where + + + align:start position:0% +C which is an expansion path where +Capital becomes more productive and + + align:start position:0% +Capital becomes more productive and + + + align:start position:0% +Capital becomes more productive and +labor becomes less + + align:start position:0% +labor becomes less + + + align:start position:0% +labor becomes less +productive that is so that is you are + + align:start position:0% +productive that is so that is you are + + + align:start position:0% +productive that is so that is you are +choosing relatively more and + + align:start position:0% +choosing relatively more and + + + align:start position:0% +choosing relatively more and +more Capital compared to labor so let's + + align:start position:0% +more Capital compared to labor so let's + + + align:start position:0% +more Capital compared to labor so let's +compare 65b to 65c in + + align:start position:0% +compare 65b to 65c in + + + align:start position:0% +compare 65b to 65c in +65b when you go from point A to point C + + align:start position:0% +65b when you go from point A to point C + + + align:start position:0% +65b when you go from point A to point C +you go from four workers to 15 workers + + align:start position:0% +you go from four workers to 15 workers + + + align:start position:0% +you go from four workers to 15 workers +but only three machine to S and a half + + align:start position:0% +but only three machine to S and a half + + + align:start position:0% +but only three machine to S and a half +machines okay go from point A to C and + + align:start position:0% +machines okay go from point A to C and + + + align:start position:0% +machines okay go from point A to C and +65b the number of workers goes up almost + + align:start position:0% +65b the number of workers goes up almost + + + align:start position:0% +65b the number of workers goes up almost +four times the number of machines only + + align:start position:0% +four times the number of machines only + + + align:start position:0% +four times the number of machines only +goes up two and a half + + align:start position:0% +goes up two and a half + + + align:start position:0% +goes up two and a half +times on the other hand with figure + + align:start position:0% +times on the other hand with figure + + + align:start position:0% +times on the other hand with figure +65c the number of workers going from a + + align:start position:0% +65c the number of workers going from a + + + align:start position:0% +65c the number of workers going from a +to c goes from 7 to 16 which is a little + + align:start position:0% +to c goes from 7 to 16 which is a little + + + align:start position:0% +to c goes from 7 to 16 which is a little +more than twice the of machines goes + + align:start position:0% +more than twice the of machines goes + + + align:start position:0% +more than twice the of machines goes +from 1.5 to 7 which is almost five times + + align:start position:0% +from 1.5 to 7 which is almost five times + + + align:start position:0% +from 1.5 to 7 which is almost five times +as + + align:start position:0% +as + + + align:start position:0% +as +much capital's becoming more productive + + align:start position:0% +much capital's becoming more productive + + + align:start position:0% +much capital's becoming more productive +workers becom less productive in 65c + + align:start position:0% +workers becom less productive in 65c + + + align:start position:0% +workers becom less productive in 65c +this might be something might Happ for + + align:start position:0% +this might be something might Happ for + + + align:start position:0% +this might be something might Happ for +like a heavy machinery + + align:start position:0% +like a heavy machinery + + + align:start position:0% +like a heavy machinery +plant okay where over time more you want + + align:start position:0% +plant okay where over time more you want + + + align:start position:0% +plant okay where over time more you want +more and more machines and you fur and + + align:start position:0% +more and more machines and you fur and + + + align:start position:0% +more and more machines and you fur and +fewer workers to run + + align:start position:0% +fewer workers to run + + + align:start position:0% +fewer workers to run +them the point of this is not to say + + align:start position:0% +them the point of this is not to say + + + align:start position:0% +them the point of this is not to say +that I can tell you what these speciic + + align:start position:0% +that I can tell you what these speciic + + + align:start position:0% +that I can tell you what these speciic +examples are and each of these obviously + + align:start position:0% +examples are and each of these obviously + + + align:start position:0% +examples are and each of these obviously +have different production functions + + align:start position:0% +have different production functions + + + align:start position:0% +have different production functions +under them it's just to show you that + + align:start position:0% +under them it's just to show you that + + + align:start position:0% +under them it's just to show you that +long run expansion paths can vary in the + + align:start position:0% +long run expansion paths can vary in the + + + align:start position:0% +long run expansion paths can vary in the +real world it's basically a question of + + align:start position:0% +real world it's basically a question of + + + align:start position:0% +real world it's basically a question of +as you want to produce + + align:start position:0% +as you want to produce + + + align:start position:0% +as you want to produce +more does labor and capital become + + align:start position:0% +more does labor and capital become + + + align:start position:0% +more does labor and capital become +equally more + + align:start position:0% +equally more + + + align:start position:0% +equally more +productive okay questions about + + align:start position:0% +productive okay questions about + + + align:start position:0% +productive okay questions about +that + + align:start position:0% + + + + align:start position:0% + +yeah down if I can't I haven't got + + align:start position:0% +yeah down if I can't I haven't got + + + align:start position:0% +yeah down if I can't I haven't got +talked about shutdown yet you're you're + + align:start position:0% +talked about shutdown yet you're you're + + + align:start position:0% +talked about shutdown yet you're you're +a bit ahead of me that that is related + + align:start position:0% +a bit ahead of me that that is related + + + align:start position:0% +a bit ahead of me that that is related +to how you're going to decide on your + + align:start position:0% +to how you're going to decide on your + + + align:start position:0% +to how you're going to decide on your +que and I'm gonna get to that next + + align:start position:0% +que and I'm gonna get to that next + + + align:start position:0% +que and I'm gonna get to that next +lecture okay so next lecture I haven't + + align:start position:0% +lecture okay so next lecture I haven't + + + align:start position:0% +lecture okay so next lecture I haven't +told you how you choose q but next + + align:start position:0% +told you how you choose q but next + + + align:start position:0% +told you how you choose q but next +lecture I will I'm going to choose the + + align:start position:0% +lecture I will I'm going to choose the + + + align:start position:0% +lecture I will I'm going to choose the +one extra step that lets you choose q + + align:start position:0% +one extra step that lets you choose q + + + align:start position:0% +one extra step that lets you choose q +but before I do I want to ask a sort of + + align:start position:0% +but before I do I want to ask a sort of + + + align:start position:0% +but before I do I want to ask a sort of +existential question which is how do we + + align:start position:0% +existential question which is how do we + + + align:start position:0% +existential question which is how do we +actually measure + + align:start position:0% +actually measure + + + align:start position:0% +actually measure +costs in the real world step four + + align:start position:0% +costs in the real world step four + + + align:start position:0% +costs in the real world step four +measuring + + align:start position:0% +measuring + + + align:start position:0% +measuring +costs and this is where I get to tell + + align:start position:0% +costs and this is where I get to tell + + + align:start position:0% +costs and this is where I get to tell +you that economics is just cooler than + + align:start position:0% +you that economics is just cooler than + + + align:start position:0% +you that economics is just cooler than +accounting and let me explain why + + align:start position:0% +accounting and let me explain why + + + align:start position:0% +accounting and let me explain why +okay accounting only considers the cash + + align:start position:0% +okay accounting only considers the cash + + + align:start position:0% +okay accounting only considers the cash +flow costs that you that you have when + + align:start position:0% +flow costs that you that you have when + + + align:start position:0% +flow costs that you that you have when +you start a firm economics more + + align:start position:0% +you start a firm economics more + + + align:start position:0% +you start a firm economics more +appropriately considers opportunity + + align:start position:0% +appropriately considers opportunity + + + align:start position:0% +appropriately considers opportunity +costs as + + align:start position:0% +costs as + + + align:start position:0% +costs as +well okay so + + align:start position:0% +well okay so + + + align:start position:0% +well okay so +profits is revenue Minus cost we're + + align:start position:0% +profits is revenue Minus cost we're + + + align:start position:0% +profits is revenue Minus cost we're +going to focus on the costs here costs + + align:start position:0% +going to focus on the costs here costs + + + align:start position:0% +going to focus on the costs here costs +and accounting are literally what you + + align:start position:0% +and accounting are literally what you + + + align:start position:0% +and accounting are literally what you +spend in economics they're what your + + align:start position:0% +spend in economics they're what your + + + align:start position:0% +spend in economics they're what your +opportunity cost is and those could + + align:start position:0% +opportunity cost is and those could + + + align:start position:0% +opportunity cost is and those could +differ so let me give you a simple + + align:start position:0% +differ so let me give you a simple + + + align:start position:0% +differ so let me give you a simple +example you're going to start a website + + align:start position:0% +example you're going to start a website + + + align:start position:0% +example you're going to start a website +design firm when you gradu that's kind + + align:start position:0% +design firm when you gradu that's kind + + + align:start position:0% +design firm when you gradu that's kind +of out of date but you know whatever + + align:start position:0% +of out of date but you know whatever + + + align:start position:0% +of out of date but you know whatever +okay you going to start a website design + + align:start position:0% +okay you going to start a website design + + + align:start position:0% +okay you going to start a website design +firm when you graduate okay and that + + align:start position:0% +firm when you graduate okay and that + + + align:start position:0% +firm when you graduate okay and that +involves you working + + align:start position:0% +involves you working + + + align:start position:0% +involves you working +full-time plus some slave programmer you + + align:start position:0% +full-time plus some slave programmer you + + + align:start position:0% +full-time plus some slave programmer you +can hire for $40,000 a year okay so + + align:start position:0% +can hire for $40,000 a year okay so + + + align:start position:0% +can hire for $40,000 a year okay so +you're going to work full-time and hire + + align:start position:0% +you're going to work full-time and hire + + + align:start position:0% +you're going to work full-time and hire +the program for $40,000 a year moreover + + align:start position:0% +the program for $40,000 a year moreover + + + align:start position:0% +the program for $40,000 a year moreover +you the program you don't even need to + + align:start position:0% +you the program you don't even need to + + + align:start position:0% +you the program you don't even need to +buy a computer for the programmer + + align:start position:0% +buy a computer for the programmer + + + align:start position:0% +buy a computer for the programmer +because you have an extra computer + + align:start position:0% +because you have an extra computer + + + align:start position:0% +because you have an extra computer +that's got one more year before it + + align:start position:0% +that's got one more year before it + + + align:start position:0% +that's got one more year before it +becomes useless so you can give that + + align:start position:0% +becomes useless so you can give that + + + align:start position:0% +becomes useless so you can give that +computer to the programmer and they can + + align:start position:0% +computer to the programmer and they can + + + align:start position:0% +computer to the programmer and they can +use that for the year so you're going + + align:start position:0% +use that for the year so you're going + + + align:start position:0% +use that for the year so you're going +have a one-year company okay you're + + align:start position:0% +have a one-year company okay you're + + + align:start position:0% +have a one-year company okay you're +going to pay it's you're going to work + + align:start position:0% +going to pay it's you're going to work + + + align:start position:0% +going to pay it's you're going to work +full-time you're going to pay your + + align:start position:0% +full-time you're going to pay your + + + align:start position:0% +full-time you're going to pay your +programmer $40,000 and you give your + + align:start position:0% +programmer $40,000 and you give your + + + align:start position:0% +programmer $40,000 and you give your +program or this computer you have that + + align:start position:0% +program or this computer you have that + + + align:start position:0% +program or this computer you have that +one more year to work and let's say your + + align:start position:0% +one more year to work and let's say your + + + align:start position:0% +one more year to work and let's say your +goal is by the end of year one I want to + + align:start position:0% +goal is by the end of year one I want to + + + align:start position:0% +goal is by the end of year one I want to +be making a profit okay my parents will + + align:start position:0% +be making a profit okay my parents will + + + align:start position:0% +be making a profit okay my parents will +be mad at me if I take more than one + + align:start position:0% +be mad at me if I take more than one + + + align:start position:0% +be mad at me if I take more than one +year with this by the end of year one I + + align:start position:0% +year with this by the end of year one I + + + align:start position:0% +year with this by the end of year one I +want to make a profit and let's say at + + align:start position:0% +want to make a profit and let's say at + + + align:start position:0% +want to make a profit and let's say at +the end of year one your revenues are + + align:start position:0% +the end of year one your revenues are + + + align:start position:0% +the end of year one your revenues are +$660,000 + + align:start position:0% +$660,000 + + + align:start position:0% +$660,000 +we could say to your parents who are + + align:start position:0% +we could say to your parents who are + + + align:start position:0% +we could say to your parents who are +accountants well gee I earned + + align:start position:0% +accountants well gee I earned + + + align:start position:0% +accountants well gee I earned +$60,000 I paid my programmer + + align:start position:0% +$60,000 I paid my programmer + + + align:start position:0% +$60,000 I paid my programmer +$40,000 that's my cost so I made profit + + align:start position:0% +$40,000 that's my cost so I made profit + + + align:start position:0% +$40,000 that's my cost so I made profit +of + + align:start position:0% + + + + align:start position:0% + +$220,000 see my company's great your + + align:start position:0% +$220,000 see my company's great your + + + align:start position:0% +$220,000 see my company's great your +accounting parents we's say an + + align:start position:0% +accounting parents we's say an + + + align:start position:0% +accounting parents we's say an +accounting mom and economics dad the + + align:start position:0% +accounting mom and economics dad the + + + align:start position:0% +accounting mom and economics dad the +accounting mom is fool but the economics + + align:start position:0% +accounting mom is fool but the economics + + + align:start position:0% +accounting mom is fool but the economics +dad is not because what does the + + align:start position:0% +dad is not because what does the + + + align:start position:0% +dad is not because what does the +economics dad point + + align:start position:0% + + + + align:start position:0% + +out + + align:start position:0% +out + + + align:start position:0% +out +yeah yeah well go on what about let's + + align:start position:0% +yeah yeah well go on what about let's + + + align:start position:0% +yeah yeah well go on what about let's +talk about your + + align:start position:0% + + + + align:start position:0% + +time there's an opportunity cost of the + + align:start position:0% +time there's an opportunity cost of the + + + align:start position:0% +time there's an opportunity cost of the +year you spent with this firm and you're + + align:start position:0% +year you spent with this firm and you're + + + align:start position:0% +year you spent with this firm and you're +an MIT graduate for God's sake who knows + + align:start position:0% +an MIT graduate for God's sake who knows + + + align:start position:0% +an MIT graduate for God's sake who knows +you could have made like I don't know + + align:start position:0% +you could have made like I don't know + + + align:start position:0% +you could have made like I don't know +100K 200k who knows what you guys make + + align:start position:0% +100K 200k who knows what you guys make + + + align:start position:0% +100K 200k who knows what you guys make +these days okay let's say you could have + + align:start position:0% +these days okay let's say you could have + + + align:start position:0% +these days okay let's say you could have +made + + align:start position:0% +made + + + align:start position:0% +made +100K you did not make 100K by starting + + align:start position:0% +100K you did not make 100K by starting + + + align:start position:0% +100K you did not make 100K by starting +this firm that is a true economic cost + + align:start position:0% +this firm that is a true economic cost + + + align:start position:0% +this firm that is a true economic cost +it's not an accounting cost but it's a + + align:start position:0% +it's not an accounting cost but it's a + + + align:start position:0% +it's not an accounting cost but it's a +true economic cost it's an opportunity + + align:start position:0% +true economic cost it's an opportunity + + + align:start position:0% +true economic cost it's an opportunity +cost you gave up 100K to do this + + align:start position:0% +cost you gave up 100K to do this + + + align:start position:0% +cost you gave up 100K to do this +moreover that computer is still one year + + align:start position:0% +moreover that computer is still one year + + + align:start position:0% +moreover that computer is still one year +left you could have sold it for + + align:start position:0% +left you could have sold it for + + + align:start position:0% +left you could have sold it for +something there's an opportunity cost + + align:start position:0% +something there's an opportunity cost + + + align:start position:0% +something there's an opportunity cost +giving to this guy you could have sold + + align:start position:0% +giving to this guy you could have sold + + + align:start position:0% +giving to this guy you could have sold +it let's say you could have sold it for + + align:start position:0% +it let's say you could have sold it for + + + align:start position:0% +it let's say you could have sold it for +,000 + + align:start position:0% +,000 + + + align:start position:0% +,000 +bucks so your opportunity costs are + + align:start position:0% +bucks so your opportunity costs are + + + align:start position:0% +bucks so your opportunity costs are +101,000 plus the 40 your total costs are + + align:start position:0% +101,000 plus the 40 your total costs are + + + align:start position:0% +101,000 plus the 40 your total costs are +141,000 this was a terrible + + align:start position:0% +141,000 this was a terrible + + + align:start position:0% +141,000 this was a terrible +idea okay your total cost of $141,000 + + align:start position:0% +idea okay your total cost of $141,000 + + + align:start position:0% +idea okay your total cost of $141,000 +you've lost + + align:start position:0% + + + + align:start position:0% + +$81,000 okay opportunity costs are real + + align:start position:0% +$81,000 okay opportunity costs are real + + + align:start position:0% +$81,000 okay opportunity costs are real +costs opportunity + + align:start position:0% +costs opportunity + + + align:start position:0% +costs opportunity +costs are the value of the best NE the + + align:start position:0% +costs are the value of the best NE the + + + align:start position:0% +costs are the value of the best NE the +next best forone alternative remember + + align:start position:0% +next best forone alternative remember + + + align:start position:0% +next best forone alternative remember +that's why we call economics to dismal + + align:start position:0% +that's why we call economics to dismal + + + align:start position:0% +that's why we call economics to dismal +science we point out nothing's free your + + align:start position:0% +science we point out nothing's free your + + + align:start position:0% +science we point out nothing's free your +time wasn't free the time you dedicated + + align:start position:0% +time wasn't free the time you dedicated + + + align:start position:0% +time wasn't free the time you dedicated +to this firm meant you could have been + + align:start position:0% +to this firm meant you could have been + + + align:start position:0% +to this firm meant you could have been +doing something else and that's not free + + align:start position:0% +doing something else and that's not free + + + align:start position:0% +doing something else and that's not free +okay and as a result you are not making + + align:start position:0% +okay and as a result you are not making + + + align:start position:0% +okay and as a result you are not making +money in this company even if you think + + align:start position:0% +money in this company even if you think + + + align:start position:0% +money in this company even if you think +they are you are okay it's not saying we + + align:start position:0% +they are you are okay it's not saying we + + + align:start position:0% +they are you are okay it's not saying we +shouldn't do startups that lose money in + + align:start position:0% +shouldn't do startups that lose money in + + + align:start position:0% +shouldn't do startups that lose money in +the first year obviously most startups + + align:start position:0% +the first year obviously most startups + + + align:start position:0% +the first year obviously most startups +lose money in the first year okay we get + + align:start position:0% +lose money in the first year okay we get + + + align:start position:0% +lose money in the first year okay we get +to that later in the semester about how + + align:start position:0% +to that later in the semester about how + + + align:start position:0% +to that later in the semester about how +you think about money companies that + + align:start position:0% +you think about money companies that + + + align:start position:0% +you think about money companies that +lose money in the first year and make + + align:start position:0% +lose money in the first year and make + + + align:start position:0% +lose money in the first year and make +money in the second year we'll come back + + align:start position:0% +money in the second year we'll come back + + + align:start position:0% +money in the second year we'll come back +to that but in this simple example you + + align:start position:0% +to that but in this simple example you + + + align:start position:0% +to that but in this simple example you +shouldn't fool yourself to think that + + align:start position:0% +shouldn't fool yourself to think that + + + align:start position:0% +shouldn't fool yourself to think that +you actually made money because of the + + align:start position:0% +you actually made money because of the + + + align:start position:0% +you actually made money because of the +opportunity costs okay questions about + + align:start position:0% +opportunity costs okay questions about + + + align:start position:0% +opportunity costs okay questions about +that all right let's stop there thanks + + align:start position:0% +that all right let's stop there thanks + + + align:start position:0% +that all right let's stop there thanks +again for all the great questions today + + align:start position:0% +again for all the great questions today + + + align:start position:0% +again for all the great questions today +and we'll come back Wednesday and figure + + align:start position:0% +and we'll come back Wednesday and figure + + + align:start position:0% +and we'll come back Wednesday and figure +out how we pick our queue \ No newline at end of file diff --git a/yK5SA6HngCY.txt b/yK5SA6HngCY.txt new file mode 100644 index 0000000000000000000000000000000000000000..afc3a7a099091cdb560a62ff560ccd2485f19ed9 --- /dev/null +++ b/yK5SA6HngCY.txt @@ -0,0 +1,12067 @@ +align:start position:0% + +The following content is provided under + + align:start position:0% +The following content is provided under + + + align:start position:0% +The following content is provided under +a Creative Common License. Your support + + align:start position:0% +a Creative Common License. Your support + + + align:start position:0% +a Creative Common License. Your support +will help MIT Open Courseware continue + + align:start position:0% +will help MIT Open Courseware continue + + + align:start position:0% +will help MIT Open Courseware continue +to offer high-quality educational + + align:start position:0% +to offer high-quality educational + + + align:start position:0% +to offer high-quality educational +resources for free. To make a donation + + align:start position:0% +resources for free. To make a donation + + + align:start position:0% +resources for free. To make a donation +or view additional materials from + + align:start position:0% +or view additional materials from + + + align:start position:0% +or view additional materials from +hundreds of MIT courses, visit MIT Open + + align:start position:0% +hundreds of MIT courses, visit MIT Open + + + align:start position:0% +hundreds of MIT courses, visit MIT Open +Courseware at ocw.mmit.edu. + + align:start position:0% + + + + align:start position:0% + +All right. So last time we started + + align:start position:0% +All right. So last time we started + + + align:start position:0% +All right. So last time we started +talking about energy absorption and I + + align:start position:0% +talking about energy absorption and I + + + align:start position:0% +talking about energy absorption and I +wanted to try to finish that up today + + align:start position:0% +wanted to try to finish that up today + + + align:start position:0% +wanted to try to finish that up today +and then next week we would talk about + + align:start position:0% +and then next week we would talk about + + + align:start position:0% +and then next week we would talk about +sandwich panels and using honeycombs and + + align:start position:0% +sandwich panels and using honeycombs and + + + align:start position:0% +sandwich panels and using honeycombs and +foams in sandwich panels. So I think we + + align:start position:0% +foams in sandwich panels. So I think we + + + align:start position:0% +foams in sandwich panels. So I think we +got as far as the idea of introducing + + align:start position:0% +got as far as the idea of introducing + + + align:start position:0% +got as far as the idea of introducing +what these energy absorption diagrams + + align:start position:0% +what these energy absorption diagrams + + + align:start position:0% +what these energy absorption diagrams +are. So let me run through this little + + align:start position:0% +are. So let me run through this little + + + align:start position:0% +are. So let me run through this little +sequence again and then I'll put the + + align:start position:0% +sequence again and then I'll put the + + + align:start position:0% +sequence again and then I'll put the +notes up on the board. So the idea is is + + align:start position:0% +notes up on the board. So the idea is is + + + align:start position:0% +notes up on the board. So the idea is is +that you have uh your compressive stress + + align:start position:0% +that you have uh your compressive stress + + + align:start position:0% +that you have uh your compressive stress +strain curve. So here's a series of + + align:start position:0% +strain curve. So here's a series of + + + align:start position:0% +strain curve. So here's a series of +curves for different densities of a + + align:start position:0% +curves for different densities of a + + + align:start position:0% +curves for different densities of a +foam. And we would do these all at the + + align:start position:0% +foam. And we would do these all at the + + + align:start position:0% +foam. And we would do these all at the +same strain rate and temperature so that + + align:start position:0% +same strain rate and temperature so that + + + align:start position:0% +same strain rate and temperature so that +those aren't variables. And then what we + + align:start position:0% +those aren't variables. And then what we + + + align:start position:0% +those aren't variables. And then what we +would do is we could turn those into + + align:start position:0% +would do is we could turn those into + + + align:start position:0% +would do is we could turn those into +energy absorption diagrams. So notice + + align:start position:0% +energy absorption diagrams. So notice + + + align:start position:0% +energy absorption diagrams. So notice +here, this is a log log plot. So here's + + align:start position:0% +here, this is a log log plot. So here's + + + align:start position:0% +here, this is a log log plot. So here's +the energy absorption here. Here's the + + align:start position:0% +the energy absorption here. Here's the + + + align:start position:0% +the energy absorption here. Here's the +peak stress here. So that's the peak + + align:start position:0% +peak stress here. So that's the peak + + + align:start position:0% +peak stress here. So that's the peak +stress up to some level of energy that + + align:start position:0% +stress up to some level of energy that + + + align:start position:0% +stress up to some level of energy that +you've absorbed. And we've normalized + + align:start position:0% +you've absorbed. And we've normalized + + + align:start position:0% +you've absorbed. And we've normalized +both of those by the solid modulus. So + + align:start position:0% +both of those by the solid modulus. So + + + align:start position:0% +both of those by the solid modulus. So +say we look at one density here. Say we + + align:start position:0% +say we look at one density here. Say we + + + align:start position:0% +say we look at one density here. Say we +look at the lowest density 0.01. So + + align:start position:0% +look at the lowest density 0.01. So + + + align:start position:0% +look at the lowest density 0.01. So +here's our curve here for the for the + + align:start position:0% +here's our curve here for the for the + + + align:start position:0% +here's our curve here for the for the +test. Uh if I go up to some stress level + + align:start position:0% +test. Uh if I go up to some stress level + + + align:start position:0% +test. Uh if I go up to some stress level +that's still in the linear elastic + + align:start position:0% +that's still in the linear elastic + + + align:start position:0% +that's still in the linear elastic +region, then that's going to translate + + align:start position:0% +region, then that's going to translate + + + align:start position:0% +region, then that's going to translate +into somewhere along here on the energy + + align:start position:0% +into somewhere along here on the energy + + + align:start position:0% +into somewhere along here on the energy +absorption curve. And one of the things + + align:start position:0% +absorption curve. And one of the things + + + align:start position:0% +absorption curve. And one of the things +we're going to do today, I'm going to + + align:start position:0% +we're going to do today, I'm going to + + + align:start position:0% +we're going to do today, I'm going to +just show you how you draw these and how + + align:start position:0% +just show you how you draw these and how + + + align:start position:0% +just show you how you draw these and how +you can sort of set them up. And you can + + align:start position:0% +you can sort of set them up. And you can + + + align:start position:0% +you can sort of set them up. And you can +either get them from experiments. So + + align:start position:0% +either get them from experiments. So + + + align:start position:0% +either get them from experiments. So +this is kind of say the top curve or + + align:start position:0% +this is kind of say the top curve or + + + align:start position:0% +this is kind of say the top curve or +experiments doing it from experiments or + + align:start position:0% +experiments doing it from experiments or + + + align:start position:0% +experiments doing it from experiments or +you can use the models for the um foams + + align:start position:0% +you can use the models for the um foams + + + align:start position:0% +you can use the models for the um foams +to do it as well. So we'll see how you + + align:start position:0% +to do it as well. So we'll see how you + + + align:start position:0% +to do it as well. So we'll see how you +can do it from both ways. So this would + + align:start position:0% +can do it from both ways. So this would + + + align:start position:0% +can do it from both ways. So this would +be the linear elastic bit here. This + + align:start position:0% +be the linear elastic bit here. This + + + align:start position:0% +be the linear elastic bit here. This +vertical part where the energy is + + align:start position:0% +vertical part where the energy is + + + align:start position:0% +vertical part where the energy is +increasing but the peak stress isn't + + align:start position:0% +increasing but the peak stress isn't + + + align:start position:0% +increasing but the peak stress isn't +increasing that corresponds to the + + align:start position:0% +increasing that corresponds to the + + + align:start position:0% +increasing that corresponds to the +plateau here. And then this part here + + align:start position:0% +plateau here. And then this part here + + + align:start position:0% +plateau here. And then this part here +where the energy is not increasing very + + align:start position:0% +where the energy is not increasing very + + + align:start position:0% +where the energy is not increasing very +much but the stress increases a lot that + + align:start position:0% +much but the stress increases a lot that + + + align:start position:0% +much but the stress increases a lot that +corresponds to the densification part + + align:start position:0% +corresponds to the densification part + + + align:start position:0% +corresponds to the densification part +over there. Okay. So what you would do + + align:start position:0% +over there. Okay. So what you would do + + + align:start position:0% +over there. Okay. So what you would do +is you would do tests on foams of + + align:start position:0% +is you would do tests on foams of + + + align:start position:0% +is you would do tests on foams of +different densities and from the test + + align:start position:0% +different densities and from the test + + + align:start position:0% +different densities and from the test +data you could draw an energy absorption + + align:start position:0% +data you could draw an energy absorption + + + align:start position:0% +data you could draw an energy absorption +curve for each density. So you plot you + + align:start position:0% +curve for each density. So you plot you + + + align:start position:0% +curve for each density. So you plot you +know there's four different densities + + align:start position:0% +know there's four different densities + + + align:start position:0% +know there's four different densities +here. So it's sort of forms a family of + + align:start position:0% +here. So it's sort of forms a family of + + + align:start position:0% +here. So it's sort of forms a family of +these curves and then what you do is you + + align:start position:0% +these curves and then what you do is you + + + align:start position:0% +these curves and then what you do is you +say and I think we talked about this + + align:start position:0% +say and I think we talked about this + + + align:start position:0% +say and I think we talked about this +last time that the the place you want to + + align:start position:0% +last time that the the place you want to + + + align:start position:0% +last time that the the place you want to +be is at this shoulder point. You want + + align:start position:0% +be is at this shoulder point. You want + + + align:start position:0% +be is at this shoulder point. You want +to be absorbing as much energy as + + align:start position:0% +to be absorbing as much energy as + + + align:start position:0% +to be absorbing as much energy as +possible at that plateau stress. So you + + align:start position:0% +possible at that plateau stress. So you + + + align:start position:0% +possible at that plateau stress. So you +want to be at the point just before it + + align:start position:0% +want to be at the point just before it + + + align:start position:0% +want to be at the point just before it +kind of turns around to the + + align:start position:0% +kind of turns around to the + + + align:start position:0% +kind of turns around to the +densification regime. So you can mark uh + + align:start position:0% +densification regime. So you can mark uh + + + align:start position:0% +densification regime. So you can mark uh +that little shoulder point for each + + align:start position:0% +that little shoulder point for each + + + align:start position:0% +that little shoulder point for each +density. So here's like 0.01, here's 03, + + align:start position:0% +density. So here's like 0.01, here's 03, + + + align:start position:0% +density. So here's like 0.01, here's 03, +and then so on. And then those points + + align:start position:0% +and then so on. And then those points + + + align:start position:0% +and then so on. And then those points +can be connected by a line. So that + + align:start position:0% +can be connected by a line. So that + + + align:start position:0% +can be connected by a line. So that +heavy line then connects those sort of + + align:start position:0% +heavy line then connects those sort of + + + align:start position:0% +heavy line then connects those sort of +shoulder points or those optimum points. + + align:start position:0% +shoulder points or those optimum points. + + + align:start position:0% +shoulder points or those optimum points. +And then what you can do is then repeat + + align:start position:0% +And then what you can do is then repeat + + + align:start position:0% +And then what you can do is then repeat +this whole process for different strain + + align:start position:0% +this whole process for different strain + + + align:start position:0% +this whole process for different strain +rates. So this family of lines here is + + align:start position:0% +rates. So this family of lines here is + + + align:start position:0% +rates. So this family of lines here is +at different strain rates. So these + + align:start position:0% +at different strain rates. So these + + + align:start position:0% +at different strain rates. So these +lines, this set that goes this way + + align:start position:0% +lines, this set that goes this way + + + align:start position:0% +lines, this set that goes this way +corresponds to this line here. And if + + align:start position:0% +corresponds to this line here. And if + + + align:start position:0% +corresponds to this line here. And if +you do them at different strain rates, + + align:start position:0% +you do them at different strain rates, + + + align:start position:0% +you do them at different strain rates, +where the shoulder is appears at a + + align:start position:0% +where the shoulder is appears at a + + + align:start position:0% +where the shoulder is appears at a +slightly different point. And so if you + + align:start position:0% +slightly different point. And so if you + + + align:start position:0% +slightly different point. And so if you +mark those shoulder points, you can draw + + align:start position:0% +mark those shoulder points, you can draw + + + align:start position:0% +mark those shoulder points, you can draw +these lines here that connect up for one + + align:start position:0% +these lines here that connect up for one + + + align:start position:0% +these lines here that connect up for one +relative density. So this uh line on the + + align:start position:0% +relative density. So this uh line on the + + + align:start position:0% +relative density. So this uh line on the +left hand side here, these are all + + align:start position:0% +left hand side here, these are all + + + align:start position:0% +left hand side here, these are all +relative densities of 0.01. These ones + + align:start position:0% +relative densities of 0.01. These ones + + + align:start position:0% +relative densities of 0.01. These ones +are all relative densities of 0.03. So + + align:start position:0% +are all relative densities of 0.03. So + + + align:start position:0% +are all relative densities of 0.03. So +this diagram down here, you know, it + + align:start position:0% +this diagram down here, you know, it + + + align:start position:0% +this diagram down here, you know, it +doesn't really look like this at all. It + + align:start position:0% +doesn't really look like this at all. It + + + align:start position:0% +doesn't really look like this at all. It +doesn't look like the basic energy + + align:start position:0% +doesn't look like the basic energy + + + align:start position:0% +doesn't look like the basic energy +absorption diagram, but it actually has + + align:start position:0% +absorption diagram, but it actually has + + + align:start position:0% +absorption diagram, but it actually has +information for what the optimum would + + align:start position:0% +information for what the optimum would + + + align:start position:0% +information for what the optimum would +be for a range of densities and a range + + align:start position:0% +be for a range of densities and a range + + + align:start position:0% +be for a range of densities and a range +of strain rates. Okay, so typically + + align:start position:0% +of strain rates. Okay, so typically + + + align:start position:0% +of strain rates. Okay, so typically +these foams are visco elastic and they + + align:start position:0% +these foams are visco elastic and they + + + align:start position:0% +these foams are visco elastic and they +have some strain rate sensitivity. So + + align:start position:0% +have some strain rate sensitivity. So + + + align:start position:0% +have some strain rate sensitivity. So +you'd like to get the strain rate + + align:start position:0% +you'd like to get the strain rate + + + align:start position:0% +you'd like to get the strain rate +sensitivity into it. And it's not shown + + align:start position:0% +sensitivity into it. And it's not shown + + + align:start position:0% +sensitivity into it. And it's not shown +here, but you could do the same thing at + + align:start position:0% +here, but you could do the same thing at + + + align:start position:0% +here, but you could do the same thing at +a constant strain rate and varying the + + align:start position:0% +a constant strain rate and varying the + + + align:start position:0% +a constant strain rate and varying the +temperature, too. So if you had things + + align:start position:0% +temperature, too. So if you had things + + + align:start position:0% +temperature, too. So if you had things +at different temperatures, you could do + + align:start position:0% +at different temperatures, you could do + + + align:start position:0% +at different temperatures, you could do +the same kind of idea. Okay. So are we + + align:start position:0% +the same kind of idea. Okay. So are we + + + align:start position:0% +the same kind of idea. Okay. So are we +good with how this works? because I'm + + align:start position:0% +good with how this works? because I'm + + + align:start position:0% +good with how this works? because I'm +now I'm going to write some stuff notes + + align:start position:0% +now I'm going to write some stuff notes + + + align:start position:0% +now I'm going to write some stuff notes +on the board so you can kind of have it + + align:start position:0% +on the board so you can kind of have it + + + align:start position:0% +on the board so you can kind of have it +in your notes. Okay. + + align:start position:0% + + + + align:start position:0% + +So the idea is that you turn your stress + + align:start position:0% +So the idea is that you turn your stress + + + align:start position:0% +So the idea is that you turn your stress +strain curve that looks something like + + align:start position:0% +strain curve that looks something like + + + align:start position:0% +strain curve that looks something like +that into an energy absorption diagram. + + align:start position:0% +that into an energy absorption diagram. + + + align:start position:0% +that into an energy absorption diagram. +And + + align:start position:0% + + + + align:start position:0% + +you can plot + + align:start position:0% +you can plot + + + align:start position:0% +you can plot +on log log scales the energy versus the + + align:start position:0% +on log log scales the energy versus the + + + align:start position:0% +on log log scales the energy versus the +peak stress and you get something like + + align:start position:0% +peak stress and you get something like + + + align:start position:0% +peak stress and you get something like +that. And this point here, I'm going to + + align:start position:0% +that. And this point here, I'm going to + + + align:start position:0% +that. And this point here, I'm going to +call the shoulder point. + + align:start position:0% + + + + align:start position:0% + +And that would use the material in the + + align:start position:0% +And that would use the material in the + + + align:start position:0% +And that would use the material in the +most efficient way. You get the most + + align:start position:0% +most efficient way. You get the most + + + align:start position:0% +most efficient way. You get the most +energy absorption without getting higher + + align:start position:0% +energy absorption without getting higher + + + align:start position:0% +energy absorption without getting higher +than that plateau stress. + + align:start position:0% + + + + align:start position:0% + +So we can say at the stress plateau, + + align:start position:0% + + + + align:start position:0% + +the energy increases without much + + align:start position:0% +the energy increases without much + + + align:start position:0% +the energy increases without much +increase in the peak stress. + + align:start position:0% + + + + align:start position:0% + +And then as the foam densifies + + align:start position:0% + + + + align:start position:0% + +then you get an increase + + align:start position:0% + + + + align:start position:0% + +in that peak stress with little increase + + align:start position:0% +in that peak stress with little increase + + + align:start position:0% +in that peak stress with little increase +in and the energy absorbed. + + align:start position:0% + + + + align:start position:0% + +And so ideally you want to be at that + + align:start position:0% +And so ideally you want to be at that + + + align:start position:0% +And so ideally you want to be at that +shoulder point. + + align:start position:0% + + + + align:start position:0% + +So to construct these energy diagrams, + + align:start position:0% +So to construct these energy diagrams, + + + align:start position:0% +So to construct these energy diagrams, +you can test a series of foams at + + align:start position:0% +you can test a series of foams at + + + align:start position:0% +you can test a series of foams at +different relative densities and + + align:start position:0% +different relative densities and + + + align:start position:0% +different relative densities and +constant strain rate and temperature. + + align:start position:0% + + + + align:start position:0% + +And then you make that plot of the + + align:start position:0% +And then you make that plot of the + + + align:start position:0% +And then you make that plot of the +energy absorbed normalized by the + + align:start position:0% +energy absorbed normalized by the + + + align:start position:0% +energy absorbed normalized by the +solid modulus versus the peak stress + + align:start position:0% +solid modulus versus the peak stress + + + align:start position:0% +solid modulus versus the peak stress +normalized by the solid modulus for each + + align:start position:0% +normalized by the solid modulus for each + + + align:start position:0% +normalized by the solid modulus for each +curve. + + align:start position:0% + + + + align:start position:0% + +And typically what people do is they + + align:start position:0% +And typically what people do is they + + + align:start position:0% +And typically what people do is they +would take the solid modulus at a + + align:start position:0% +would take the solid modulus at a + + + align:start position:0% +would take the solid modulus at a +constant strain rate and temperature. So + + align:start position:0% +constant strain rate and temperature. So + + + align:start position:0% +constant strain rate and temperature. So +you don't have to introduce that as + + align:start position:0% +you don't have to introduce that as + + + align:start position:0% +you don't have to introduce that as +well. + + align:start position:0% + + + + align:start position:0% + +Then you would mark the density for each + + align:start position:0% +Then you would mark the density for each + + + align:start position:0% +Then you would mark the density for each +of those shoulder points. + + align:start position:0% +of those shoulder points. + + + align:start position:0% +of those shoulder points. +And then you would connect them. + + align:start position:0% + + + + align:start position:0% + +And then you could repeat this whole + + align:start position:0% +And then you could repeat this whole + + + align:start position:0% +And then you could repeat this whole +process for different strain rates. + + align:start position:0% + + + + align:start position:0% + +And then you would draw the final + + align:start position:0% +And then you would draw the final + + + align:start position:0% +And then you would draw the final +diagram at the bottom where you have + + align:start position:0% +diagram at the bottom where you have + + + align:start position:0% +diagram at the bottom where you have +this family of lines that describes the + + align:start position:0% +this family of lines that describes the + + + align:start position:0% +this family of lines that describes the +shoulder points for different densities + + align:start position:0% +shoulder points for different densities + + + align:start position:0% +shoulder points for different densities +and different strain rates. + + align:start position:0% + + + + align:start position:0% + +And you could treat different + + align:start position:0% +And you could treat different + + + align:start position:0% +And you could treat different +temperatures in the same way if you + + align:start position:0% +temperatures in the same way if you + + + align:start position:0% +temperatures in the same way if you +wanted to. you would hold the strain + + align:start position:0% +wanted to. you would hold the strain + + + align:start position:0% +wanted to. you would hold the strain +rate constant and vary the temperature. + + align:start position:0% +rate constant and vary the temperature. + + + align:start position:0% +rate constant and vary the temperature. +Okay, so it's kind of a nice way of just + + align:start position:0% +Okay, so it's kind of a nice way of just + + + align:start position:0% +Okay, so it's kind of a nice way of just +putting a lot of information on one + + align:start position:0% +putting a lot of information on one + + + align:start position:0% +putting a lot of information on one +diagram. + + align:start position:0% +diagram. + + + align:start position:0% +diagram. +So one of the things about this is that + + align:start position:0% +So one of the things about this is that + + + align:start position:0% +So one of the things about this is that +because we're normalizing by ES and if + + align:start position:0% +because we're normalizing by ES and if + + + align:start position:0% +because we're normalizing by ES and if +you think of elasttoic foams, elasttoic + + align:start position:0% +you think of elasttoic foams, elasttoic + + + align:start position:0% +you think of elasttoic foams, elasttoic +foams both the Young's modulus depends + + align:start position:0% +foams both the Young's modulus depends + + + align:start position:0% +foams both the Young's modulus depends +on ES and the plateau stress depends on + + align:start position:0% +on ES and the plateau stress depends on + + + align:start position:0% +on ES and the plateau stress depends on +ES. So the the Young's modulus depends + + align:start position:0% +ES. So the the Young's modulus depends + + + align:start position:0% +ES. So the the Young's modulus depends +on the stiffness of the solid and also + + align:start position:0% +on the stiffness of the solid and also + + + align:start position:0% +on the stiffness of the solid and also +because the plateau stress is related to + + align:start position:0% +because the plateau stress is related to + + + align:start position:0% +because the plateau stress is related to +elastic buckling it also depends on the + + align:start position:0% +elastic buckling it also depends on the + + + align:start position:0% +elastic buckling it also depends on the +modulus of the solid. So for elastoic + + align:start position:0% +modulus of the solid. So for elastoic + + + align:start position:0% +modulus of the solid. So for elastoic +foams you can really if because you + + align:start position:0% +foams you can really if because you + + + align:start position:0% +foams you can really if because you +normalize it with respect to es one of + + align:start position:0% +normalize it with respect to es one of + + + align:start position:0% +normalize it with respect to es one of +these diagrams will represent all + + align:start position:0% +these diagrams will represent all + + + align:start position:0% +these diagrams will represent all +elasttoic foams. Okay so that's rather a + + align:start position:0% +elasttoic foams. Okay so that's rather a + + + align:start position:0% +elasttoic foams. Okay so that's rather a +nice thing. So you can have different + + align:start position:0% +nice thing. So you can have different + + + align:start position:0% +nice thing. So you can have different +elasttoic foams but one of those + + align:start position:0% +elasttoic foams but one of those + + + align:start position:0% +elasttoic foams but one of those +diagrams is going to represent all of + + align:start position:0% +diagrams is going to represent all of + + + align:start position:0% +diagrams is going to represent all of +them. + + align:start position:0% + + + + align:start position:0% + +So we can say elastoic foams can all be + + align:start position:0% +So we can say elastoic foams can all be + + + align:start position:0% +So we can say elastoic foams can all be +plotted on one plot or one curve since + + align:start position:0% +plotted on one plot or one curve since + + + align:start position:0% +plotted on one plot or one curve since +both the modulus and the plateau stress + + align:start position:0% +both the modulus and the plateau stress + + + align:start position:0% +both the modulus and the plateau stress +are related to ES. Yes. + + align:start position:0% + + + + align:start position:0% + +So if we look at this next figure here, + + align:start position:0% +So if we look at this next figure here, + + + align:start position:0% +So if we look at this next figure here, +maybe I'll just wait a minute for people + + align:start position:0% +maybe I'll just wait a minute for people + + + align:start position:0% +maybe I'll just wait a minute for people +to stop writing. + + align:start position:0% + + + + align:start position:0% + +Yep. Some people write faster than + + align:start position:0% +Yep. Some people write faster than + + + align:start position:0% +Yep. Some people write faster than +others. + + align:start position:0% + + + + align:start position:0% + +Okay. So, if we look at this next plot + + align:start position:0% +Okay. So, if we look at this next plot + + + align:start position:0% +Okay. So, if we look at this next plot +here, here's uh compressive stress and + + align:start position:0% +here, here's uh compressive stress and + + + align:start position:0% +here, here's uh compressive stress and +strain. These tests are done for one + + align:start position:0% +strain. These tests are done for one + + + align:start position:0% +strain. These tests are done for one +density but a different strain rate. So, + + align:start position:0% +density but a different strain rate. So, + + + align:start position:0% +density but a different strain rate. So, +it's kind of the other other version of + + align:start position:0% +it's kind of the other other version of + + + align:start position:0% +it's kind of the other other version of +this. But here's the stress strain + + align:start position:0% +this. But here's the stress strain + + + align:start position:0% +this. But here's the stress strain +curves here. And here's the energy + + align:start position:0% +curves here. And here's the energy + + + align:start position:0% +curves here. And here's the energy +absorption diagram that's derived from + + align:start position:0% +absorption diagram that's derived from + + + align:start position:0% +absorption diagram that's derived from +those. And then here's a sort of a + + align:start position:0% +those. And then here's a sort of a + + + align:start position:0% +those. And then here's a sort of a +summary diagram uh that has the + + align:start position:0% +summary diagram uh that has the + + + align:start position:0% +summary diagram uh that has the +different strain rates and that would + + align:start position:0% +different strain rates and that would + + + align:start position:0% +different strain rates and that would +have different densities here. And the + + align:start position:0% +have different densities here. And the + + + align:start position:0% +have different densities here. And the +idea is this diagram here could + + align:start position:0% +idea is this diagram here could + + + align:start position:0% +idea is this diagram here could +represent all elasttoic foam. So this + + align:start position:0% +represent all elasttoic foam. So this + + + align:start position:0% +represent all elasttoic foam. So this +has been put together for polyurethane + + align:start position:0% +has been put together for polyurethane + + + align:start position:0% +has been put together for polyurethane +but it could have been you know it + + align:start position:0% +but it could have been you know it + + + align:start position:0% +but it could have been you know it +should be able to represent other sorts + + align:start position:0% +should be able to represent other sorts + + + align:start position:0% +should be able to represent other sorts +of flexible um elasttoic foams. + + align:start position:0% +of flexible um elasttoic foams. + + + align:start position:0% +of flexible um elasttoic foams. +Sorry. diagrams then the + + align:start position:0% +Sorry. diagrams then the + + + align:start position:0% +Sorry. diagrams then the +intersection of the strain rate line and + + align:start position:0% +intersection of the strain rate line and + + + align:start position:0% +intersection of the strain rate line and +your relative density line should be the + + align:start position:0% +your relative density line should be the + + + align:start position:0% +your relative density line should be the +shoulder position. + + align:start position:0% +shoulder position. + + + align:start position:0% +shoulder position. +Yeah, exactly. And so like so this line + + align:start position:0% +Yeah, exactly. And so like so this line + + + align:start position:0% +Yeah, exactly. And so like so this line +here is for 01 and that one's for 003. + + align:start position:0% +here is for 01 and that one's for 003. + + + align:start position:0% +here is for 01 and that one's for 003. +So 0.02 is going to be you know you'd + + align:start position:0% +So 0.02 is going to be you know you'd + + + align:start position:0% +So 0.02 is going to be you know you'd +have to kind of interpolate somewhere in + + align:start position:0% +have to kind of interpolate somewhere in + + + align:start position:0% +have to kind of interpolate somewhere in +between there. Okay. So so we've just + + align:start position:0% +between there. Okay. So so we've just + + + align:start position:0% +between there. Okay. So so we've just +put on certain values because we're not + + align:start position:0% +put on certain values because we're not + + + align:start position:0% +put on certain values because we're not +going to put on a million values. So you + + align:start position:0% +going to put on a million values. So you + + + align:start position:0% +going to put on a million values. So you +just put on certain ones and then + + align:start position:0% +just put on certain ones and then + + + align:start position:0% +just put on certain ones and then +and then you can sort of estimate where + + align:start position:0% +and then you can sort of estimate where + + + align:start position:0% +and then you can sort of estimate where +other densities would appear on there. + + align:start position:0% +other densities would appear on there. + + + align:start position:0% +other densities would appear on there. +Okay. Uh so here's another example here. + + align:start position:0% +Okay. Uh so here's another example here. + + + align:start position:0% +Okay. Uh so here's another example here. +These are curves for two different foam. + + align:start position:0% +These are curves for two different foam. + + + align:start position:0% +These are curves for two different foam. +So here's a polyurethane and a + + align:start position:0% +So here's a polyurethane and a + + + align:start position:0% +So here's a polyurethane and a +polyethylene. So these are both + + align:start position:0% +polyethylene. So these are both + + + align:start position:0% +polyethylene. So these are both +elastimemers and one is the dashed line + + align:start position:0% +elastimemers and one is the dashed line + + + align:start position:0% +elastimemers and one is the dashed line +and one's the solid line. And you can + + align:start position:0% +and one's the solid line. And you can + + + align:start position:0% +and one's the solid line. And you can +kind of see how the lines um kind of + + align:start position:0% +kind of see how the lines um kind of + + + align:start position:0% +kind of see how the lines um kind of +mesh up. So here's a density of 0.01 for + + align:start position:0% +mesh up. So here's a density of 0.01 for + + + align:start position:0% +mesh up. So here's a density of 0.01 for +the polyurethane. Here's 0.05 05 for the + + align:start position:0% +the polyurethane. Here's 0.05 05 for the + + + align:start position:0% +the polyurethane. Here's 0.05 05 for the +polyurethane. And here's 006 for the + + align:start position:0% +polyurethane. And here's 006 for the + + + align:start position:0% +polyurethane. And here's 006 for the +polyethylene. And you can see how the + + align:start position:0% +polyethylene. And you can see how the + + + align:start position:0% +polyethylene. And you can see how the +006 and the 0.05, they're not quite on + + align:start position:0% +006 and the 0.05, they're not quite on + + + align:start position:0% +006 and the 0.05, they're not quite on +top of each other, but they're pretty + + align:start position:0% +top of each other, but they're pretty + + + align:start position:0% +top of each other, but they're pretty +close to coming on top of each other. + + align:start position:0% +close to coming on top of each other. + + + align:start position:0% +close to coming on top of each other. +And then 0.12. And so you get sort of a + + align:start position:0% +And then 0.12. And so you get sort of a + + + align:start position:0% +And then 0.12. And so you get sort of a +family of them for the different + + align:start position:0% +family of them for the different + + + align:start position:0% +family of them for the different +densities. Okay? And you can also do + + align:start position:0% +densities. Okay? And you can also do + + + align:start position:0% +densities. Okay? And you can also do +this for materials that have a yield + + align:start position:0% +this for materials that have a yield + + + align:start position:0% +this for materials that have a yield +point. So polymethacry liid has a yield + + align:start position:0% +point. So polymethacry liid has a yield + + + align:start position:0% +point. So polymethacry liid has a yield +point. So you do exactly the same kind + + align:start position:0% +point. So you do exactly the same kind + + + align:start position:0% +point. So you do exactly the same kind +of thing. Uh so here's the energy + + align:start position:0% +of thing. Uh so here's the energy + + + align:start position:0% +of thing. Uh so here's the energy +absorption diagram that's been developed + + align:start position:0% +absorption diagram that's been developed + + + align:start position:0% +absorption diagram that's been developed +from the stress strain curves. But now + + align:start position:0% +from the stress strain curves. But now + + + align:start position:0% +from the stress strain curves. But now +this curve here or this set of curves + + align:start position:0% +this curve here or this set of curves + + + align:start position:0% +this curve here or this set of curves +here is really just valid for one ratio + + align:start position:0% +here is really just valid for one ratio + + + align:start position:0% +here is really just valid for one ratio +of sigma to ES. So the solid module or + + align:start position:0% +of sigma to ES. So the solid module or + + + align:start position:0% +of sigma to ES. So the solid module or +solid yield strength to the solid + + align:start position:0% +solid yield strength to the solid + + + align:start position:0% +solid yield strength to the solid +modulus. So it's valid for whatever it + + align:start position:0% +modulus. So it's valid for whatever it + + + align:start position:0% +modulus. So it's valid for whatever it +was for that particular type of um foam + + align:start position:0% +was for that particular type of um foam + + + align:start position:0% +was for that particular type of um foam +the polymethyl + + align:start position:0% +the polymethyl + + + align:start position:0% +the polymethyl +methylacrimid. + + align:start position:0% +methylacrimid. + + + align:start position:0% +methylacrimid. +Um, + + align:start position:0% +Um, + + + align:start position:0% +Um, +so I'll just say if we have foams + + align:start position:0% + + + + align:start position:0% + +that are made from a material with a + + align:start position:0% +that are made from a material with a + + + align:start position:0% +that are made from a material with a +yield point and so they have a a plastic + + align:start position:0% +yield point and so they have a a plastic + + + align:start position:0% +yield point and so they have a a plastic +collapse stress + + align:start position:0% +collapse stress + + + align:start position:0% +collapse stress +then the curve + + align:start position:0% + + + + align:start position:0% + +will be valid + + align:start position:0% + + + + align:start position:0% + +for foams with the same ratio of sigma + + align:start position:0% +for foams with the same ratio of sigma + + + align:start position:0% +for foams with the same ratio of sigma +ys to Yes. + + align:start position:0% + + + + align:start position:0% + +So in that case there for the poly m the + + align:start position:0% +So in that case there for the poly m the + + + align:start position:0% +So in that case there for the poly m the +facral limit that ratio is about equal + + align:start position:0% +facral limit that ratio is about equal + + + align:start position:0% +facral limit that ratio is about equal +to 1 over 30. + + align:start position:0% +to 1 over 30. + + + align:start position:0% +to 1 over 30. +So that plot would probably give not a + + align:start position:0% +So that plot would probably give not a + + + align:start position:0% +So that plot would probably give not a +bad description of other foams with the + + align:start position:0% +bad description of other foams with the + + + align:start position:0% +bad description of other foams with the +same value of sigma ys over + + align:start position:0% +same value of sigma ys over + + + align:start position:0% +same value of sigma ys over +es. + + align:start position:0% +es. + + + align:start position:0% +es. +So the idea here is we can generate + + align:start position:0% +So the idea here is we can generate + + + align:start position:0% +So the idea here is we can generate +these diagrams + + align:start position:0% +these diagrams + + + align:start position:0% +these diagrams +either from data the way those ones have + + align:start position:0% +either from data the way those ones have + + + align:start position:0% +either from data the way those ones have +been done or from the models. + + align:start position:0% + + + + align:start position:0% + +Okay. + + align:start position:0% + + + + align:start position:0% + +So another way to generate these is to + + align:start position:0% +So another way to generate these is to + + + align:start position:0% +So another way to generate these is to +think about the models that we have for + + align:start position:0% +think about the models that we have for + + + align:start position:0% +think about the models that we have for +the foams and the foam behavior. So we + + align:start position:0% +the foams and the foam behavior. So we + + + align:start position:0% +the foams and the foam behavior. So we +have an equation that describes the + + align:start position:0% +have an equation that describes the + + + align:start position:0% +have an equation that describes the +Young's modulus. We have equations that + + align:start position:0% +Young's modulus. We have equations that + + + align:start position:0% +Young's modulus. We have equations that +describe the plateau stresses. We have + + align:start position:0% +describe the plateau stresses. We have + + + align:start position:0% +describe the plateau stresses. We have +an empirical equation for the + + align:start position:0% +an empirical equation for the + + + align:start position:0% +an empirical equation for the +densification strain and we can use + + align:start position:0% +densification strain and we can use + + + align:start position:0% +densification strain and we can use +those to generate these diagrams and + + align:start position:0% +those to generate these diagrams and + + + align:start position:0% +those to generate these diagrams and +they're kind of useful because they kind + + align:start position:0% +they're kind of useful because they kind + + + align:start position:0% +they're kind of useful because they kind +of show you what's going on on a sort of + + align:start position:0% +of show you what's going on on a sort of + + + align:start position:0% +of show you what's going on on a sort of +mechanis mechanistic basis. So this is a + + align:start position:0% +mechanis mechanistic basis. So this is a + + + align:start position:0% +mechanis mechanistic basis. So this is a +diagram here that's been generated for + + align:start position:0% +diagram here that's been generated for + + + align:start position:0% +diagram here that's been generated for +open cell elastoic foams. Here's our + + align:start position:0% +open cell elastoic foams. Here's our + + + align:start position:0% +open cell elastoic foams. Here's our +energy absorbed. Here's our peak stress + + align:start position:0% +energy absorbed. Here's our peak stress + + + align:start position:0% +energy absorbed. Here's our peak stress +down here. This little inset is sort of + + align:start position:0% +down here. This little inset is sort of + + + align:start position:0% +down here. This little inset is sort of +a schematic of the idealized foam + + align:start position:0% +a schematic of the idealized foam + + + align:start position:0% +a schematic of the idealized foam +behavior. So here's the Young's modulus. + + align:start position:0% +behavior. So here's the Young's modulus. + + + align:start position:0% +behavior. So here's the Young's modulus. +Here's the elastic collapse stress. + + align:start position:0% +Here's the elastic collapse stress. + + + align:start position:0% +Here's the elastic collapse stress. +Here's the densification over here. So + + align:start position:0% +Here's the densification over here. So + + + align:start position:0% +Here's the densification over here. So +obviously it's kind of a very idealized + + align:start position:0% +obviously it's kind of a very idealized + + + align:start position:0% +obviously it's kind of a very idealized +setup. Um but we can generate this + + align:start position:0% +setup. Um but we can generate this + + + align:start position:0% +setup. Um but we can generate this +diagram and I'm going to go through the + + align:start position:0% +diagram and I'm going to go through the + + + align:start position:0% +diagram and I'm going to go through the +equations that'll let us do that. So, + + align:start position:0% +equations that'll let us do that. So, + + + align:start position:0% +equations that'll let us do that. So, +um, one thing to note is here's the sort + + align:start position:0% +um, one thing to note is here's the sort + + + align:start position:0% +um, one thing to note is here's the sort +of curves for each density. Here's this + + align:start position:0% +of curves for each density. Here's this + + + align:start position:0% +of curves for each density. Here's this +line that connects the shoulder points. + + align:start position:0% +line that connects the shoulder points. + + + align:start position:0% +line that connects the shoulder points. +There's a couple of other lines on here + + align:start position:0% +There's a couple of other lines on here + + + align:start position:0% +There's a couple of other lines on here +that I just wanted to mention something + + align:start position:0% +that I just wanted to mention something + + + align:start position:0% +that I just wanted to mention something +about. If you think about the densities, + + align:start position:0% +about. If you think about the densities, + + + align:start position:0% +about. If you think about the densities, +like that's 0.01, this is 0.03, that's + + align:start position:0% +like that's 0.01, this is 0.03, that's + + + align:start position:0% +like that's 0.01, this is 0.03, that's +0.1. If you had a fully dense solid that + + align:start position:0% +0.1. If you had a fully dense solid that + + + align:start position:0% +0.1. If you had a fully dense solid that +was made of the same elastimer, you + + align:start position:0% +was made of the same elastimer, you + + + align:start position:0% +was made of the same elastimer, you +could plot the curve for that, and that + + align:start position:0% +could plot the curve for that, and that + + + align:start position:0% +could plot the curve for that, and that +is going to show up over here. So, this + + align:start position:0% +is going to show up over here. So, this + + + align:start position:0% +is going to show up over here. So, this +is kind of an upper bound. It can't get + + align:start position:0% +is kind of an upper bound. It can't get + + + align:start position:0% +is kind of an upper bound. It can't get +any more than that, right? Or uh and + + align:start position:0% +any more than that, right? Or uh and + + + align:start position:0% +any more than that, right? Or uh and +we've also got a dotted line here which + + align:start position:0% +we've also got a dotted line here which + + + align:start position:0% +we've also got a dotted line here which +takes into account fluid flow within the + + align:start position:0% +takes into account fluid flow within the + + + align:start position:0% +takes into account fluid flow within the +cells. So there can be some fluid flow + + align:start position:0% +cells. So there can be some fluid flow + + + align:start position:0% +cells. So there can be some fluid flow +and because we haven't talked about + + align:start position:0% +and because we haven't talked about + + + align:start position:0% +and because we haven't talked about +that, we're not going to go into that. + + align:start position:0% +that, we're not going to go into that. + + + align:start position:0% +that, we're not going to go into that. +So we can just ignore that dotted line + + align:start position:0% +So we can just ignore that dotted line + + + align:start position:0% +So we can just ignore that dotted line +for now. Okay. Okay. So let me let me go + + align:start position:0% +for now. Okay. Okay. So let me let me go + + + align:start position:0% +for now. Okay. Okay. So let me let me go +through how we can do the modeling. + + align:start position:0% +through how we can do the modeling. + + + align:start position:0% +through how we can do the modeling. +So, we're going to divide the stress + + align:start position:0% +So, we're going to divide the stress + + + align:start position:0% +So, we're going to divide the stress +strain curve up into bits, and I'm going + + align:start position:0% +strain curve up into bits, and I'm going + + + align:start position:0% +strain curve up into bits, and I'm going +to write equations for the energy + + align:start position:0% +to write equations for the energy + + + align:start position:0% +to write equations for the energy +absorbed for each bit. So, we're going + + align:start position:0% +absorbed for each bit. So, we're going + + + align:start position:0% +absorbed for each bit. So, we're going +to start + + align:start position:0% +to start + + + align:start position:0% +to start +with a linear elastic behavior. + + align:start position:0% + + + + align:start position:0% + +And I'm going to + + align:start position:0% +And I'm going to + + + align:start position:0% +And I'm going to +let's see uh yeah, so let me just note + + align:start position:0% +let's see uh yeah, so let me just note + + + align:start position:0% +let's see uh yeah, so let me just note +here that this is the densification + + align:start position:0% +here that this is the densification + + + align:start position:0% +here that this is the densification +strain out here. And this strain epsilon + + align:start position:0% +strain out here. And this strain epsilon + + + align:start position:0% +strain out here. And this strain epsilon +kn corresponds to the strain at which we + + align:start position:0% +kn corresponds to the strain at which we + + + align:start position:0% +kn corresponds to the strain at which we +first reach the stress plateau. So here + + align:start position:0% +first reach the stress plateau. So here + + + align:start position:0% +first reach the stress plateau. So here +for the linear elastic part I'm going to + + align:start position:0% +for the linear elastic part I'm going to + + + align:start position:0% +for the linear elastic part I'm going to +say that the strain is less than that. + + align:start position:0% +say that the strain is less than that. + + + align:start position:0% +say that the strain is less than that. +So the strain is less than epsilon kn + + align:start position:0% +So the strain is less than epsilon kn + + + align:start position:0% +So the strain is less than epsilon kn +and then I can say + + align:start position:0% +and then I can say + + + align:start position:0% +and then I can say +the energy absorbed. + + align:start position:0% +the energy absorbed. + + + align:start position:0% +the energy absorbed. +So if you just remember from hook's law + + align:start position:0% +So if you just remember from hook's law + + + align:start position:0% +So if you just remember from hook's law +and linear elasticity energy under the + + align:start position:0% +and linear elasticity energy under the + + + align:start position:0% +and linear elasticity energy under the +stress strain curve for the linear + + align:start position:0% +stress strain curve for the linear + + + align:start position:0% +stress strain curve for the linear +elastic part is 12 of sigma squar over + + align:start position:0% +elastic part is 12 of sigma squar over + + + align:start position:0% +elastic part is 12 of sigma squar over +e. So I'm going to call sigma the + + align:start position:0% +e. So I'm going to call sigma the + + + align:start position:0% +e. So I'm going to call sigma the +whatever the stress is going to be the + + align:start position:0% +whatever the stress is going to be the + + + align:start position:0% +whatever the stress is going to be the +peak stress that we get to. And now + + align:start position:0% +peak stress that we get to. And now + + + align:start position:0% +peak stress that we get to. And now +we're going to divide by E of the foam + + align:start position:0% +we're going to divide by E of the foam + + + align:start position:0% +we're going to divide by E of the foam +because these are our foams here. And I + + align:start position:0% +because these are our foams here. And I + + + align:start position:0% +because these are our foams here. And I +can use our model here to say + + align:start position:0% + + + + align:start position:0% + +and then I got to divide that by ES + + align:start position:0% +and then I got to divide that by ES + + + align:start position:0% +and then I got to divide that by ES +because I've normalized here. + + align:start position:0% + + + + align:start position:0% + +So, because I know from my modeling that + + align:start position:0% +So, because I know from my modeling that + + + align:start position:0% +So, because I know from my modeling that +the Young's modulus of the foam is just + + align:start position:0% +the Young's modulus of the foam is just + + + align:start position:0% +the Young's modulus of the foam is just +equal to ES times the relative density + + align:start position:0% +equal to ES times the relative density + + + align:start position:0% +equal to ES times the relative density +squared for the open cell foam, that + + align:start position:0% +squared for the open cell foam, that + + + align:start position:0% +squared for the open cell foam, that +means I've now got an ES squared in the + + align:start position:0% +means I've now got an ES squared in the + + + align:start position:0% +means I've now got an ES squared in the +denominator. So, I've got sigma P over + + align:start position:0% +denominator. So, I've got sigma P over + + + align:start position:0% +denominator. So, I've got sigma P over +ES^2 and then I've got a one over the + + align:start position:0% +ES^2 and then I've got a one over the + + + align:start position:0% +ES^2 and then I've got a one over the +relative density squared term. Okay, + + align:start position:0% +relative density squared term. Okay, + + + align:start position:0% +relative density squared term. Okay, +so that uh factor there, that equation + + align:start position:0% +so that uh factor there, that equation + + + align:start position:0% +so that uh factor there, that equation +there gives you these first set of lines + + align:start position:0% +there gives you these first set of lines + + + align:start position:0% +there gives you these first set of lines +here. Gives you that bit and this bit + + align:start position:0% +here. Gives you that bit and this bit + + + align:start position:0% +here. Gives you that bit and this bit +and that bit. Okay, so it gives you + + align:start position:0% +and that bit. Okay, so it gives you + + + align:start position:0% +and that bit. Okay, so it gives you +those first parts of the energy + + align:start position:0% +those first parts of the energy + + + align:start position:0% +those first parts of the energy +absorption diagram. + + align:start position:0% + + + + align:start position:0% + +And then if we look at the stress + + align:start position:0% +And then if we look at the stress + + + align:start position:0% +And then if we look at the stress +plateau, so here we're going to say that + + align:start position:0% +plateau, so here we're going to say that + + + align:start position:0% +plateau, so here we're going to say that +epsilon kn is less than epsilon is less + + align:start position:0% +epsilon kn is less than epsilon is less + + + align:start position:0% +epsilon kn is less than epsilon is less +than the densification strain. So we're + + align:start position:0% +than the densification strain. So we're + + + align:start position:0% +than the densification strain. So we're +on the plateau somewhere. And now the + + align:start position:0% +on the plateau somewhere. And now the + + + align:start position:0% +on the plateau somewhere. And now the +energy absorbed is just going to be our + + align:start position:0% +energy absorbed is just going to be our + + + align:start position:0% +energy absorbed is just going to be our +plateau stress times the amount of + + align:start position:0% +plateau stress times the amount of + + + align:start position:0% +plateau stress times the amount of +strain we've got. + + align:start position:0% +strain we've got. + + + align:start position:0% +strain we've got. +So that's epsilon minus epsilon kn. And + + align:start position:0% +So that's epsilon minus epsilon kn. And + + + align:start position:0% +So that's epsilon minus epsilon kn. And +if I normalize with respect to the solid + + align:start position:0% +if I normalize with respect to the solid + + + align:start position:0% +if I normalize with respect to the solid +modulus, I can write down that my + + align:start position:0% +modulus, I can write down that my + + + align:start position:0% +modulus, I can write down that my +plateau stress is 0.05 005 + + align:start position:0% + + + + align:start position:0% + +time the relative density squared and + + align:start position:0% +time the relative density squared and + + + align:start position:0% +time the relative density squared and +then multiply that times + + align:start position:0% +then multiply that times + + + align:start position:0% +then multiply that times +epsilon minus epsilon kn. Okay. + + align:start position:0% + + + + align:start position:0% + +So that equation then corresponds to + + align:start position:0% +So that equation then corresponds to + + + align:start position:0% +So that equation then corresponds to +these vertical parts. So this part here, + + align:start position:0% +these vertical parts. So this part here, + + + align:start position:0% +these vertical parts. So this part here, +that part there, this part here, it + + align:start position:0% +that part there, this part here, it + + + align:start position:0% +that part there, this part here, it +corresponds to those vertical lines on + + align:start position:0% +corresponds to those vertical lines on + + + align:start position:0% +corresponds to those vertical lines on +the figure. + + align:start position:0% + + + + align:start position:0% + +vertical lines on the diagram. And then + + align:start position:0% +vertical lines on the diagram. And then + + + align:start position:0% +vertical lines on the diagram. And then +the plateau stress is going to end at + + align:start position:0% +the plateau stress is going to end at + + + align:start position:0% +the plateau stress is going to end at +the densification strain. + + align:start position:0% + + + + align:start position:0% + +And at that point, the energy diagram is + + align:start position:0% +And at that point, the energy diagram is + + + align:start position:0% +And at that point, the energy diagram is +just going to become vertical. + + align:start position:0% + + + + align:start position:0% + +Okay. And then the last part. Let me try + + align:start position:0% +Okay. And then the last part. Let me try + + + align:start position:0% +Okay. And then the last part. Let me try +and rub this off a little better. + + align:start position:0% + + + + align:start position:0% + +And then the last part is when we're at + + align:start position:0% +And then the last part is when we're at + + + align:start position:0% +And then the last part is when we're at +the end of the stress plateau + + align:start position:0% + + + + align:start position:0% + +and the strain is equal to that + + align:start position:0% +and the strain is equal to that + + + align:start position:0% +and the strain is equal to that +densification strain. + + align:start position:0% +densification strain. + + + align:start position:0% +densification strain. +And so the amount of energy we absorb + + align:start position:0% +And so the amount of energy we absorb + + + align:start position:0% +And so the amount of energy we absorb +here is really going to be the maximum + + align:start position:0% + + + + align:start position:0% + +So this is the energy that's going to + + align:start position:0% +So this is the energy that's going to + + + align:start position:0% +So this is the energy that's going to +correspond to that shoulder point that + + align:start position:0% +correspond to that shoulder point that + + + align:start position:0% +correspond to that shoulder point that +I've been talking about. So I'm going to + + align:start position:0% +I've been talking about. So I'm going to + + + align:start position:0% +I've been talking about. So I'm going to +call that W max + + align:start position:0% +call that W max + + + align:start position:0% +call that W max +and normalize that with respect to ES. + + align:start position:0% +and normalize that with respect to ES. + + + align:start position:0% +and normalize that with respect to ES. +And that's then going to be + + align:start position:0% +And that's then going to be + + + align:start position:0% +And that's then going to be +our plateau stress times the + + align:start position:0% +our plateau stress times the + + + align:start position:0% +our plateau stress times the +densification strain. + + align:start position:0% +densification strain. + + + align:start position:0% +densification strain. +And the densification strain + + align:start position:0% +And the densification strain + + + align:start position:0% +And the densification strain +was just 1 minus 1.4 times the relative + + align:start position:0% +was just 1 minus 1.4 times the relative + + + align:start position:0% +was just 1 minus 1.4 times the relative +density. + + align:start position:0% + + + + align:start position:0% + +So here I'm assuming + + align:start position:0% +So here I'm assuming + + + align:start position:0% +So here I'm assuming +that the densification strain is very + + align:start position:0% +that the densification strain is very + + + align:start position:0% +that the densification strain is very +much bigger than the strain at which the + + align:start position:0% +much bigger than the strain at which the + + + align:start position:0% +much bigger than the strain at which the +buckling first occurs. And I'm + + align:start position:0% +buckling first occurs. And I'm + + + align:start position:0% +buckling first occurs. And I'm +neglecting that linear elastic part. + + align:start position:0% + + + + align:start position:0% + +So then we could say the optimum foam + + align:start position:0% + + + + align:start position:0% + +is at that shoulder point + + align:start position:0% + + + + align:start position:0% + +and I can say that the peak stress at + + align:start position:0% +and I can say that the peak stress at + + + align:start position:0% +and I can say that the peak stress at +that point is just equal to the plateau + + align:start position:0% +that point is just equal to the plateau + + + align:start position:0% +that point is just equal to the plateau +stress. + + align:start position:0% + + + + align:start position:0% + +And I can what I want to do is get an + + align:start position:0% +And I can what I want to do is get an + + + align:start position:0% +And I can what I want to do is get an +equation for that um solid line up here + + align:start position:0% +equation for that um solid line up here + + + align:start position:0% +equation for that um solid line up here +that connects all those shoulder points. + + align:start position:0% +that connects all those shoulder points. + + + align:start position:0% +that connects all those shoulder points. +So I want an equation in terms of the + + align:start position:0% +So I want an equation in terms of the + + + align:start position:0% +So I want an equation in terms of the +energy and the peak stress instead of in + + align:start position:0% +energy and the peak stress instead of in + + + align:start position:0% +energy and the peak stress instead of in +terms of the density. So what I'm going + + align:start position:0% +terms of the density. So what I'm going + + + align:start position:0% +terms of the density. So what I'm going +to do is solve this for the density and + + align:start position:0% +to do is solve this for the density and + + + align:start position:0% +to do is solve this for the density and +then plug that back into there. + + align:start position:0% + + + + align:start position:0% + +So that's + + align:start position:0% + + + + align:start position:0% + +so I get that the relative density is + + align:start position:0% +so I get that the relative density is + + + align:start position:0% +so I get that the relative density is +then 20 times the peak stress over the + + align:start position:0% +then 20 times the peak stress over the + + + align:start position:0% +then 20 times the peak stress over the +solid modulus and I take the square root + + align:start position:0% +solid modulus and I take the square root + + + align:start position:0% +solid modulus and I take the square root +of that + + align:start position:0% + + + + align:start position:0% + +and now I can substitute this up here + + align:start position:0% +and now I can substitute this up here + + + align:start position:0% +and now I can substitute this up here +for the relative density. + + align:start position:0% +for the relative density. + + + align:start position:0% +for the relative density. +I think I need another board. + + align:start position:0% + + + + align:start position:0% + +So then I've got this is my my peak + + align:start position:0% +So then I've got this is my my peak + + + align:start position:0% +So then I've got this is my my peak +stress or my plateau stress over ES and + + align:start position:0% +stress or my plateau stress over ES and + + + align:start position:0% +stress or my plateau stress over ES and +this is all just the densification or + + align:start position:0% +this is all just the densification or + + + align:start position:0% +this is all just the densification or +one yeah this is all just the + + align:start position:0% +one yeah this is all just the + + + align:start position:0% +one yeah this is all just the +densification strain and that's just 1 - + + align:start position:0% +densification strain and that's just 1 - + + + align:start position:0% +densification strain and that's just 1 - +1.4 four times the relative density. But + + align:start position:0% +1.4 four times the relative density. But + + + align:start position:0% +1.4 four times the relative density. But +now I'm putting the relative density in + + align:start position:0% +now I'm putting the relative density in + + + align:start position:0% +now I'm putting the relative density in +terms of the peak stress or the plateau + + align:start position:0% +terms of the peak stress or the plateau + + + align:start position:0% +terms of the peak stress or the plateau +stress. + + align:start position:0% + + + + align:start position:0% + +So if I just simplify that slightly with + + align:start position:0% +So if I just simplify that slightly with + + + align:start position:0% +So if I just simplify that slightly with +the constant, + + align:start position:0% +the constant, + + + align:start position:0% +the constant, +it's 1 - 6.26 + + align:start position:0% +it's 1 - 6.26 + + + align:start position:0% +it's 1 - 6.26 +* sigma p over e s + + align:start position:0% +* sigma p over e s + + + align:start position:0% +* sigma p over e s +to the 1/2 power. + + align:start position:0% + + + + align:start position:0% + +So that equation there describes the + + align:start position:0% +So that equation there describes the + + + align:start position:0% +So that equation there describes the +Oops. Oops. Oh, come on. No more + + align:start position:0% +Oops. Oops. Oh, come on. No more + + + align:start position:0% +Oops. Oops. Oh, come on. No more +updates. No updates. Go away. + + align:start position:0% +updates. No updates. Go away. + + + align:start position:0% +updates. No updates. Go away. +Ah. So that equation there describes + + align:start position:0% +Ah. So that equation there describes + + + align:start position:0% +Ah. So that equation there describes +this line here that connects those + + align:start position:0% +this line here that connects those + + + align:start position:0% +this line here that connects those +shoulder points. Okay. And that's the + + align:start position:0% +shoulder points. Okay. And that's the + + + align:start position:0% +shoulder points. Okay. And that's the +line you're sort of the most interested + + align:start position:0% +line you're sort of the most interested + + + align:start position:0% +line you're sort of the most interested +in because each of those shoulder points + + align:start position:0% +in because each of those shoulder points + + + align:start position:0% +in because each of those shoulder points +is a point where the foam is being used + + align:start position:0% +is a point where the foam is being used + + + align:start position:0% +is a point where the foam is being used +in the most efficient way or the optimum + + align:start position:0% +in the most efficient way or the optimum + + + align:start position:0% +in the most efficient way or the optimum +way. Okay. + + align:start position:0% + + + + align:start position:0% + +And then let's see. Is that going to + + align:start position:0% +And then let's see. Is that going to + + + align:start position:0% +And then let's see. Is that going to +fit? Let me try the other board. + + align:start position:0% + + + + align:start position:0% + +And then the last thing we can do is + + align:start position:0% +And then the last thing we can do is + + + align:start position:0% +And then the last thing we can do is +calculate that line that corresponds to + + align:start position:0% +calculate that line that corresponds to + + + align:start position:0% +calculate that line that corresponds to +the dense solid. Yeah. + + align:start position:0% +the dense solid. Yeah. + + + align:start position:0% +the dense solid. Yeah. +On that it says it corresponds to the + + align:start position:0% +On that it says it corresponds to the + + + align:start position:0% +On that it says it corresponds to the +vertical lines on the diagram. And then + + align:start position:0% +vertical lines on the diagram. And then + + + align:start position:0% +vertical lines on the diagram. And then +later it says then it becomes vertical. + + align:start position:0% +later it says then it becomes vertical. + + + align:start position:0% +later it says then it becomes vertical. +Is that referring to two different + + align:start position:0% +Is that referring to two different + + + align:start position:0% +Is that referring to two different +diagrams? + + align:start position:0% +diagrams? + + + align:start position:0% +diagrams? +Um, so this stress plateau equation here + + align:start position:0% +Um, so this stress plateau equation here + + + align:start position:0% +Um, so this stress plateau equation here +corresponds to these vertical lines + + align:start position:0% +corresponds to these vertical lines + + + align:start position:0% +corresponds to these vertical lines +here. So for for a relative density of + + align:start position:0% +here. So for for a relative density of + + + align:start position:0% +here. So for for a relative density of +0.01 it corresponds to that part and for + + align:start position:0% +0.01 it corresponds to that part and for + + + align:start position:0% +0.01 it corresponds to that part and for +03 it's this part and for 01 it's that + + align:start position:0% +03 it's this part and for 01 it's that + + + align:start position:0% +03 it's this part and for 01 it's that +part. Okay. + + align:start position:0% +part. Okay. + + + align:start position:0% +part. Okay. +But then the third point then w versus + + align:start position:0% +But then the third point then w versus + + + align:start position:0% +But then the third point then w versus +sigma becomes vertical. + + align:start position:0% +sigma becomes vertical. + + + align:start position:0% +sigma becomes vertical. +Oh so well the plateau stress ends at + + align:start position:0% +Oh so well the plateau stress ends at + + + align:start position:0% +Oh so well the plateau stress ends at +the densification strain. So the plateau + + align:start position:0% +the densification strain. So the plateau + + + align:start position:0% +the densification strain. So the plateau +stress ends here. Oh, let's see. And + + align:start position:0% +stress ends here. Oh, let's see. And + + + align:start position:0% +stress ends here. Oh, let's see. And +then it becomes should be horizontal. + + align:start position:0% +then it becomes should be horizontal. + + + align:start position:0% +then it becomes should be horizontal. +Sorry, sorry. Sorry. + + align:start position:0% + + + + align:start position:0% + +Okay. Sorry. Happy. + + align:start position:0% + + + + align:start position:0% + +Now I'm going to rub that all off. + + align:start position:0% + + + + align:start position:0% + +Okay, everybody get this. Rub it off. + + align:start position:0% + + + + align:start position:0% + +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +So then the last part + + align:start position:0% + + + + align:start position:0% + +is what happens when the foam is + + align:start position:0% +is what happens when the foam is + + + align:start position:0% +is what happens when the foam is +densified. And if it was fully dense, + + align:start position:0% +densified. And if it was fully dense, + + + align:start position:0% +densified. And if it was fully dense, +and you never really can get to this + + align:start position:0% +and you never really can get to this + + + align:start position:0% +and you never really can get to this +point, but if it was fully dense, you + + align:start position:0% +point, but if it was fully dense, you + + + align:start position:0% +point, but if it was fully dense, you +would get rid of all the pores and it + + align:start position:0% +would get rid of all the pores and it + + + align:start position:0% +would get rid of all the pores and it +would just be a solid. And then the + + align:start position:0% +would just be a solid. And then the + + + align:start position:0% +would just be a solid. And then the +energy absorption curve would be this + + align:start position:0% +energy absorption curve would be this + + + align:start position:0% +energy absorption curve would be this +curve for the solid. + + align:start position:0% +curve for the solid. + + + align:start position:0% +curve for the solid. +So I'll just say when fully densified, + + align:start position:0% + + + + align:start position:0% + +We'll just say the curve approaches + + align:start position:0% +We'll just say the curve approaches + + + align:start position:0% +We'll just say the curve approaches +that for the solid. + + align:start position:0% + + + + align:start position:0% + +Then for the solid you would just have + + align:start position:0% +Then for the solid you would just have + + + align:start position:0% +Then for the solid you would just have +that W over E S is equal to 12 + + align:start position:0% +that W over E S is equal to 12 + + + align:start position:0% +that W over E S is equal to 12 +the peak stress squared over ES. Okay. + + align:start position:0% +the peak stress squared over ES. Okay. + + + align:start position:0% +the peak stress squared over ES. Okay. +So the this model curve the curves have + + align:start position:0% +So the this model curve the curves have + + + align:start position:0% +So the this model curve the curves have +the same shape as when you get the + + align:start position:0% +the same shape as when you get the + + + align:start position:0% +the same shape as when you get the +diagrams from the experiments and you + + align:start position:0% +diagrams from the experiments and you + + + align:start position:0% +diagrams from the experiments and you +can kind of see how the different + + align:start position:0% +can kind of see how the different + + + align:start position:0% +can kind of see how the different +mechanisms of deformation and failure + + align:start position:0% +mechanisms of deformation and failure + + + align:start position:0% +mechanisms of deformation and failure +kind of contribute to the diagram where + + align:start position:0% +kind of contribute to the diagram where + + + align:start position:0% +kind of contribute to the diagram where +the diagram comes from. Okay. + + align:start position:0% +the diagram comes from. Okay. + + + align:start position:0% +the diagram comes from. Okay. +Um and I guess one other point is you + + align:start position:0% +Um and I guess one other point is you + + + align:start position:0% +Um and I guess one other point is you +can see that the foams are always going + + align:start position:0% +can see that the foams are always going + + + align:start position:0% +can see that the foams are always going +to be a lot better than the solid. And + + align:start position:0% +to be a lot better than the solid. And + + + align:start position:0% +to be a lot better than the solid. And +remember this is a log log curve. So + + align:start position:0% +remember this is a log log curve. So + + + align:start position:0% +remember this is a log log curve. So +that you know a foam that's like uh has + + align:start position:0% +that you know a foam that's like uh has + + + align:start position:0% +that you know a foam that's like uh has +a density of 3% here there's a huge + + align:start position:0% +a density of 3% here there's a huge + + + align:start position:0% +a density of 3% here there's a huge +difference in the peak stress. So say + + align:start position:0% +difference in the peak stress. So say + + + align:start position:0% +difference in the peak stress. So say +say you wanted to absorb this amount of + + align:start position:0% +say you wanted to absorb this amount of + + + align:start position:0% +say you wanted to absorb this amount of +energy up here. Uh for a foam that was + + align:start position:0% +energy up here. Uh for a foam that was + + + align:start position:0% +energy up here. Uh for a foam that was +003 dense the peak stress would be a + + align:start position:0% +003 dense the peak stress would be a + + + align:start position:0% +003 dense the peak stress would be a +little less than 10us4 normalized by the + + align:start position:0% +little less than 10us4 normalized by the + + + align:start position:0% +little less than 10us4 normalized by the +modulus and for the solid it'd be like + + align:start position:0% +modulus and for the solid it'd be like + + + align:start position:0% +modulus and for the solid it'd be like +10us2. So it's orders of magnitude + + align:start position:0% +10us2. So it's orders of magnitude + + + align:start position:0% +10us2. So it's orders of magnitude +better to have the foam rather than the + + align:start position:0% +better to have the foam rather than the + + + align:start position:0% +better to have the foam rather than the +solid. Okay. All right. + + align:start position:0% +solid. Okay. All right. + + + align:start position:0% +solid. Okay. All right. +Now let's see what else we have. So we + + align:start position:0% +Now let's see what else we have. So we + + + align:start position:0% +Now let's see what else we have. So we +we could do a similar thing for closed + + align:start position:0% +we could do a similar thing for closed + + + align:start position:0% +we could do a similar thing for closed +cell foams and you get diagrams that + + align:start position:0% +cell foams and you get diagrams that + + + align:start position:0% +cell foams and you get diagrams that +look like this. Uh one of the + + align:start position:0% +look like this. Uh one of the + + + align:start position:0% +look like this. Uh one of the +differences with the closed cell foams + + align:start position:0% +differences with the closed cell foams + + + align:start position:0% +differences with the closed cell foams +if you assume that the faces don't + + align:start position:0% +if you assume that the faces don't + + + align:start position:0% +if you assume that the faces don't +rupture the the plateau stresses and + + align:start position:0% +rupture the the plateau stresses and + + + align:start position:0% +rupture the the plateau stresses and +horizontals. You know remember we had + + align:start position:0% +horizontals. You know remember we had + + + align:start position:0% +horizontals. You know remember we had +that gas contribution and you can take + + align:start position:0% +that gas contribution and you can take + + + align:start position:0% +that gas contribution and you can take +that into account. So I'm I'm not going + + align:start position:0% +that into account. So I'm I'm not going + + + align:start position:0% +that into account. So I'm I'm not going +to go over the details of that. Um the + + align:start position:0% +to go over the details of that. Um the + + + align:start position:0% +to go over the details of that. Um the +next one I wanted to talk about was uh + + align:start position:0% +next one I wanted to talk about was uh + + + align:start position:0% +next one I wanted to talk about was uh +looking at foams that have a yield + + align:start position:0% +looking at foams that have a yield + + + align:start position:0% +looking at foams that have a yield +point. And again you can generate a + + align:start position:0% +point. And again you can generate a + + + align:start position:0% +point. And again you can generate a +similar kind of diagram but now instead + + align:start position:0% +similar kind of diagram but now instead + + + align:start position:0% +similar kind of diagram but now instead +of having an elastic failure here you've + + align:start position:0% +of having an elastic failure here you've + + + align:start position:0% +of having an elastic failure here you've +got a plastic failure you form plastic + + align:start position:0% +got a plastic failure you form plastic + + + align:start position:0% +got a plastic failure you form plastic +hinges. And then again this diagram is + + align:start position:0% +hinges. And then again this diagram is + + + align:start position:0% +hinges. And then again this diagram is +less general than the one for elastoic + + align:start position:0% +less general than the one for elastoic + + + align:start position:0% +less general than the one for elastoic +foams. So this diagram would be valid + + align:start position:0% +foams. So this diagram would be valid + + + align:start position:0% +foams. So this diagram would be valid +for whatever ratio of sigma ys over es + + align:start position:0% +for whatever ratio of sigma ys over es + + + align:start position:0% +for whatever ratio of sigma ys over es +you've done the calculation for. So this + + align:start position:0% +you've done the calculation for. So this + + + align:start position:0% +you've done the calculation for. So this +one here it's for 001. Okay. So let me + + align:start position:0% +one here it's for 001. Okay. So let me + + + align:start position:0% +one here it's for 001. Okay. So let me +just run through the same kind of + + align:start position:0% +just run through the same kind of + + + align:start position:0% +just run through the same kind of +calculation for for the plastic foams. + + align:start position:0% +calculation for for the plastic foams. + + + align:start position:0% +calculation for for the plastic foams. +Um, + + align:start position:0% + + + + align:start position:0% + +can I rub this off? Then I can use this + + align:start position:0% +can I rub this off? Then I can use this + + + align:start position:0% +can I rub this off? Then I can use this +board right here. Yeah. + + align:start position:0% + + + + align:start position:0% + +Okay. + + align:start position:0% + + + + align:start position:0% + +So the linear elastic part is just the + + align:start position:0% +So the linear elastic part is just the + + + align:start position:0% +So the linear elastic part is just the +same as for the elastoic foams. + + align:start position:0% +same as for the elastoic foams. + + + align:start position:0% +same as for the elastoic foams. +So you get W over E S is a half + + align:start position:0% +So you get W over E S is a half + + + align:start position:0% +So you get W over E S is a half +sigma P over E S squared + + align:start position:0% +sigma P over E S squared + + + align:start position:0% +sigma P over E S squared +* 1 over the relative density squared. + + align:start position:0% +* 1 over the relative density squared. + + + align:start position:0% +* 1 over the relative density squared. +So it's just the same thing. + + align:start position:0% +So it's just the same thing. + + + align:start position:0% +So it's just the same thing. +Then the stress plateau + + align:start position:0% + + + + align:start position:0% + +get W over E S is just the uh plastic + + align:start position:0% +get W over E S is just the uh plastic + + + align:start position:0% +get W over E S is just the uh plastic +collapse strength + + align:start position:0% +collapse strength + + + align:start position:0% +collapse strength +times + + align:start position:0% +times + + + align:start position:0% +times +the strain range that you go up to. So + + align:start position:0% +the strain range that you go up to. So + + + align:start position:0% +the strain range that you go up to. So +if you remember the plastic collapse + + align:start position:0% +if you remember the plastic collapse + + + align:start position:0% +if you remember the plastic collapse +strength was.3 + + align:start position:0% +strength was.3 + + + align:start position:0% +strength was.3 +sigma ys + + align:start position:0% + + + + align:start position:0% + +times the relative density to the three + + align:start position:0% +times the relative density to the three + + + align:start position:0% +times the relative density to the three +halves power and then times the strain + + align:start position:0% +halves power and then times the strain + + + align:start position:0% +halves power and then times the strain +range and then + + align:start position:0% + + + + align:start position:0% + +and then at the end of the stress + + align:start position:0% +and then at the end of the stress + + + align:start position:0% +and then at the end of the stress +plateau you've got the maximum energy + + align:start position:0% +plateau you've got the maximum energy + + + align:start position:0% +plateau you've got the maximum energy +absorbed. + + align:start position:0% +absorbed. + + + align:start position:0% +absorbed. +So normalize that by ES + + align:start position:0% +So normalize that by ES + + + align:start position:0% +So normalize that by ES +and that's going to be your peak stress + + align:start position:0% +and that's going to be your peak stress + + + align:start position:0% +and that's going to be your peak stress +over ES times the densification strain + + align:start position:0% +over ES times the densification strain + + + align:start position:0% +over ES times the densification strain +again. + + align:start position:0% + + + + align:start position:0% + +So this bit here + + align:start position:0% +So this bit here + + + align:start position:0% +So this bit here +is the densification strain. + + align:start position:0% + + + + align:start position:0% + +And then you can do a similar thing to + + align:start position:0% +And then you can do a similar thing to + + + align:start position:0% +And then you can do a similar thing to +figure out the equation of that line + + align:start position:0% +figure out the equation of that line + + + align:start position:0% +figure out the equation of that line +that joins the shoulder points. + + align:start position:0% + + + + align:start position:0% + +So the first step is to solve for the + + align:start position:0% +So the first step is to solve for the + + + align:start position:0% +So the first step is to solve for the +relative density there. + + align:start position:0% + + + + align:start position:0% + +Um, so that's + + align:start position:0% + + + + align:start position:0% + +so if this part here.3 sigma ys times + + align:start position:0% +so if this part here.3 sigma ys times + + + align:start position:0% +so if this part here.3 sigma ys times +the relative density to the three halves + + align:start position:0% +the relative density to the three halves + + + align:start position:0% +the relative density to the three halves +power is the plastic collapse stress, + + align:start position:0% +power is the plastic collapse stress, + + + align:start position:0% +power is the plastic collapse stress, +then at the densification point the + + align:start position:0% +then at the densification point the + + + align:start position:0% +then at the densification point the +relative density you can just rewrite + + align:start position:0% +relative density you can just rewrite + + + align:start position:0% +relative density you can just rewrite +that and it comes out to the 2/3 power + + align:start position:0% +that and it comes out to the 2/3 power + + + align:start position:0% +that and it comes out to the 2/3 power +because you turn the power around. And + + align:start position:0% +because you turn the power around. And + + + align:start position:0% +because you turn the power around. And +then you just substitute this up in + + align:start position:0% +then you just substitute this up in + + + align:start position:0% +then you just substitute this up in +here. + + align:start position:0% + + + + align:start position:0% + +So you get that the maximum energy + + align:start position:0% +So you get that the maximum energy + + + align:start position:0% +So you get that the maximum energy +absorbed normalized by the solid modulus + + align:start position:0% +absorbed normalized by the solid modulus + + + align:start position:0% +absorbed normalized by the solid modulus +is your peak stress time 1 - 1.4 * this + + align:start position:0% +is your peak stress time 1 - 1.4 * this + + + align:start position:0% +is your peak stress time 1 - 1.4 * this +thing in brackets to the 2/3 power the + + align:start position:0% +thing in brackets to the 2/3 power the + + + align:start position:0% +thing in brackets to the 2/3 power the +3.3 times the peak stress over the yield + + align:start position:0% +3.3 times the peak stress over the yield + + + align:start position:0% +3.3 times the peak stress over the yield +strength of the solid. And then if I + + align:start position:0% +strength of the solid. And then if I + + + align:start position:0% +strength of the solid. And then if I +just rearrange that + + align:start position:0% + + + + align:start position:0% + +and get the constants, + + align:start position:0% + + + + align:start position:0% + +it's 1 minus 3.1 + + align:start position:0% + + + + align:start position:0% + +times our ratio of the stresses there. + + align:start position:0% +times our ratio of the stresses there. + + + align:start position:0% +times our ratio of the stresses there. +Okay. + + align:start position:0% + + + + align:start position:0% + +So maybe I'll just put over here. The + + align:start position:0% +So maybe I'll just put over here. The + + + align:start position:0% +So maybe I'll just put over here. The +curves are less general than for + + align:start position:0% +curves are less general than for + + + align:start position:0% +curves are less general than for +elastimeic + + align:start position:0% +elastimeic + + + align:start position:0% +elastimeic +foams. + + align:start position:0% + + + + align:start position:0% + +Okay. So each sort of family of curves + + align:start position:0% +Okay. So each sort of family of curves + + + align:start position:0% +Okay. So each sort of family of curves +would be for a particular ratio of the + + align:start position:0% +would be for a particular ratio of the + + + align:start position:0% +would be for a particular ratio of the +solid yield strength to the solid + + align:start position:0% +solid yield strength to the solid + + + align:start position:0% +solid yield strength to the solid +modulus. Okay. + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% + + + + align:start position:0% + +So you get the idea. It's fairly + + align:start position:0% +So you get the idea. It's fairly + + + align:start position:0% +So you get the idea. It's fairly +straightforward. So I wanted to finish + + align:start position:0% +straightforward. So I wanted to finish + + + align:start position:0% +straightforward. So I wanted to finish +up this topic by giving you a few + + align:start position:0% +up this topic by giving you a few + + + align:start position:0% +up this topic by giving you a few +examples of how you can use these + + align:start position:0% +examples of how you can use these + + + align:start position:0% +examples of how you can use these +curves. So the next thing is to look at + + align:start position:0% +curves. So the next thing is to look at + + + align:start position:0% +curves. So the next thing is to look at +the selection of foams for impact + + align:start position:0% +the selection of foams for impact + + + align:start position:0% +the selection of foams for impact +protection. And typically you're given + + align:start position:0% +protection. And typically you're given + + + align:start position:0% +protection. And typically you're given +some information about the object. So + + align:start position:0% +some information about the object. So + + + align:start position:0% +some information about the object. So +typically you want to protect some + + align:start position:0% +typically you want to protect some + + + align:start position:0% +typically you want to protect some +object. It could be a computer. It could + + align:start position:0% +object. It could be a computer. It could + + + align:start position:0% +object. It could be a computer. It could +be your head, some part of your body. + + align:start position:0% +be your head, some part of your body. + + + align:start position:0% +be your head, some part of your body. +So, typically, you know something about + + align:start position:0% +So, typically, you know something about + + + align:start position:0% +So, typically, you know something about +the object you want to protect. So, you + + align:start position:0% +the object you want to protect. So, you + + + align:start position:0% +the object you want to protect. So, you +might know its mass. You might know the + + align:start position:0% +might know its mass. You might know the + + + align:start position:0% +might know its mass. You might know the +area of contact. You might say, well, if + + align:start position:0% +area of contact. You might say, well, if + + + align:start position:0% +area of contact. You might say, well, if +it's my computer, I want to make sure it + + align:start position:0% +it's my computer, I want to make sure it + + + align:start position:0% +it's my computer, I want to make sure it +doesn't break if I drop it from a height + + align:start position:0% +doesn't break if I drop it from a height + + + align:start position:0% +doesn't break if I drop it from a height +of a meter or, you know, you could say + + align:start position:0% +of a meter or, you know, you could say + + + align:start position:0% +of a meter or, you know, you could say +whatever it is, 2 meters, but you pick + + align:start position:0% +whatever it is, 2 meters, but you pick + + + align:start position:0% +whatever it is, 2 meters, but you pick +something. Uh, and so there's a certain + + align:start position:0% +something. Uh, and so there's a certain + + + align:start position:0% +something. Uh, and so there's a certain +amount of energy, you know, that you + + align:start position:0% +amount of energy, you know, that you + + + align:start position:0% +amount of energy, you know, that you +need to absorb. And you may know that + + align:start position:0% +need to absorb. And you may know that + + + align:start position:0% +need to absorb. And you may know that +the whatever the component is or the + + align:start position:0% +the whatever the component is or the + + + align:start position:0% +the whatever the component is or the +body part or whatever, there's some + + align:start position:0% +body part or whatever, there's some + + + align:start position:0% +body part or whatever, there's some +maximum acceleration you can tolerate. + + align:start position:0% +maximum acceleration you can tolerate. + + + align:start position:0% +maximum acceleration you can tolerate. +So you might say, well, I want to make + + align:start position:0% +So you might say, well, I want to make + + + align:start position:0% +So you might say, well, I want to make +sure my computer doesn't break under an + + align:start position:0% +sure my computer doesn't break under an + + + align:start position:0% +sure my computer doesn't break under an +acceleration of so much. So you're given + + align:start position:0% +acceleration of so much. So you're given + + + align:start position:0% +acceleration of so much. So you're given +the acceleration. Um, and so if you know + + align:start position:0% +the acceleration. Um, and so if you know + + + align:start position:0% +the acceleration. Um, and so if you know +the mass and the acceleration and you + + align:start position:0% +the mass and the acceleration and you + + + align:start position:0% +the mass and the acceleration and you +know the area of contact, you can figure + + align:start position:0% +know the area of contact, you can figure + + + align:start position:0% +know the area of contact, you can figure +out a force over an area and that gives + + align:start position:0% +out a force over an area and that gives + + + align:start position:0% +out a force over an area and that gives +you the peak stress. So typically you + + align:start position:0% +you the peak stress. So typically you + + + align:start position:0% +you the peak stress. So typically you +know those things in the problem and + + align:start position:0% +know those things in the problem and + + + align:start position:0% +know those things in the problem and +typically the problem involves choosing + + align:start position:0% +typically the problem involves choosing + + + align:start position:0% +typically the problem involves choosing +a material or choosing like choosing + + align:start position:0% +a material or choosing like choosing + + + align:start position:0% +a material or choosing like choosing +what kind of material do you want to + + align:start position:0% +what kind of material do you want to + + + align:start position:0% +what kind of material do you want to +make the foam out of, what density of + + align:start position:0% +make the foam out of, what density of + + + align:start position:0% +make the foam out of, what density of +foam do you want to use, what thickness + + align:start position:0% +foam do you want to use, what thickness + + + align:start position:0% +foam do you want to use, what thickness +of foam do you want to use. So, I've got + + align:start position:0% +of foam do you want to use. So, I've got + + + align:start position:0% +of foam do you want to use. So, I've got +a couple of examples uh just to show you + + align:start position:0% +a couple of examples uh just to show you + + + align:start position:0% +a couple of examples uh just to show you +how this works. So, uh let me just write + + align:start position:0% +how this works. So, uh let me just write + + + align:start position:0% +how this works. So, uh let me just write +down a couple notes and then the rest of + + align:start position:0% +down a couple notes and then the rest of + + + align:start position:0% +down a couple notes and then the rest of +it I think is I'm just going to take + + align:start position:0% +it I think is I'm just going to take + + + align:start position:0% +it I think is I'm just going to take +from the slides. + + align:start position:0% + + + + align:start position:0% + +So typically you know what it is you + + align:start position:0% +So typically you know what it is you + + + align:start position:0% +So typically you know what it is you +want to protect and you know something + + align:start position:0% +want to protect and you know something + + + align:start position:0% +want to protect and you know something +about it. + + align:start position:0% + + + + align:start position:0% + +So if you know what it is typically you + + align:start position:0% +So if you know what it is typically you + + + align:start position:0% +So if you know what it is typically you +know what the mass is. + + align:start position:0% + + + + align:start position:0% + +Uh you might know what the contact area + + align:start position:0% +Uh you might know what the contact area + + + align:start position:0% +Uh you might know what the contact area +would be. + + align:start position:0% + + + + align:start position:0% + +say a maximum drop height, + + align:start position:0% + + + + align:start position:0% + +maximum tolerable acceleration. + + align:start position:0% + + + + align:start position:0% + +So say if you're worried about brain + + align:start position:0% +So say if you're worried about brain + + + align:start position:0% +So say if you're worried about brain +injury and making a helmet, you might + + align:start position:0% +injury and making a helmet, you might + + + align:start position:0% +injury and making a helmet, you might +know what the maximum tolerable + + align:start position:0% +know what the maximum tolerable + + + align:start position:0% +know what the maximum tolerable +acceleration would be. + + align:start position:0% + + + + align:start position:0% + +So typically you know what the peak + + align:start position:0% +So typically you know what the peak + + + align:start position:0% +So typically you know what the peak +allowable stress is just from whatever + + align:start position:0% +allowable stress is just from whatever + + + align:start position:0% +allowable stress is just from whatever +the object itself is. And the variables + + align:start position:0% +the object itself is. And the variables + + + align:start position:0% +the object itself is. And the variables +that you have to play around with + + align:start position:0% +that you have to play around with + + + align:start position:0% +that you have to play around with +variables + + align:start position:0% +variables + + + align:start position:0% +variables +are things like the foam material + + align:start position:0% + + + + align:start position:0% + +the foam density + + align:start position:0% +the foam density + + + align:start position:0% +the foam density +and the foam thickness. + + align:start position:0% + + + + align:start position:0% + +So I have a couple of examples that have + + align:start position:0% +So I have a couple of examples that have + + + align:start position:0% +So I have a couple of examples that have +um sort of different setups here and + + align:start position:0% +um sort of different setups here and + + + align:start position:0% +um sort of different setups here and +we'll just see how the thing works out + + align:start position:0% +we'll just see how the thing works out + + + align:start position:0% +we'll just see how the thing works out +here. So the first example uh we're told + + align:start position:0% +here. So the first example uh we're told + + + align:start position:0% +here. So the first example uh we're told +the mass of the packaged object is half + + align:start position:0% +the mass of the packaged object is half + + + align:start position:0% +the mass of the packaged object is half +a kilogram. We're told the area of + + align:start position:0% +a kilogram. We're told the area of + + + align:start position:0% +a kilogram. We're told the area of +contact is between the foam and the + + align:start position:0% +contact is between the foam and the + + + align:start position:0% +contact is between the foam and the +object is going to be 0.01 of a meter + + align:start position:0% +object is going to be 0.01 of a meter + + + align:start position:0% +object is going to be 0.01 of a meter +squared. And we're told that it it's + + align:start position:0% +squared. And we're told that it it's + + + align:start position:0% +squared. And we're told that it it's +supposed to be designed to withstand a + + align:start position:0% +supposed to be designed to withstand a + + + align:start position:0% +supposed to be designed to withstand a +drop of 1 meter. So if the drop height + + align:start position:0% +drop of 1 meter. So if the drop height + + + align:start position:0% +drop of 1 meter. So if the drop height +is 1 meter, then the velocity is just + + align:start position:0% +is 1 meter, then the velocity is just + + + align:start position:0% +is 1 meter, then the velocity is just +the square<unk> of 2 GH. So G is + + align:start position:0% +the square<unk> of 2 GH. So G is + + + align:start position:0% +the square<unk> of 2 GH. So G is +gravity. So you can work out the + + align:start position:0% +gravity. So you can work out the + + + align:start position:0% +gravity. So you can work out the +velocity on impact would be 4.5 m/s. And + + align:start position:0% +velocity on impact would be 4.5 m/s. And + + + align:start position:0% +velocity on impact would be 4.5 m/s. And +if you have the velocity on impact and + + align:start position:0% +if you have the velocity on impact and + + + align:start position:0% +if you have the velocity on impact and +the mass, you can figure out the energy + + align:start position:0% +the mass, you can figure out the energy + + + align:start position:0% +the mass, you can figure out the energy +to be absorbed. You can say mv^2 over + + align:start position:0% +to be absorbed. You can say mv^2 over + + + align:start position:0% +to be absorbed. You can say mv^2 over +two or you could say it's mgh either + + align:start position:0% +two or you could say it's mgh either + + + align:start position:0% +two or you could say it's mgh either +way. So here it's going to work out to 5 + + align:start position:0% +way. So here it's going to work out to 5 + + + align:start position:0% +way. So here it's going to work out to 5 +jewels. + + align:start position:0% +jewels. + + + align:start position:0% +jewels. +And in this case uh we're told that the + + align:start position:0% +And in this case uh we're told that the + + + align:start position:0% +And in this case uh we're told that the +uh the maximum deceleration is 10 g. So + + align:start position:0% +uh the maximum deceleration is 10 g. So + + + align:start position:0% +uh the maximum deceleration is 10 g. So +then if that's 10 g, the maximum force + + align:start position:0% +then if that's 10 g, the maximum force + + + align:start position:0% +then if that's 10 g, the maximum force +is the mass times the acceleration that + + align:start position:0% +is the mass times the acceleration that + + + align:start position:0% +is the mass times the acceleration that +we're set to 50 newtons. And then that + + align:start position:0% +we're set to 50 newtons. And then that + + + align:start position:0% +we're set to 50 newtons. And then that +gives us a peak stress. The maximum + + align:start position:0% +gives us a peak stress. The maximum + + + align:start position:0% +gives us a peak stress. The maximum +allowable peak stress of the force over + + align:start position:0% +allowable peak stress of the force over + + + align:start position:0% +allowable peak stress of the force over +the area is 5 kons per meter squared. + + align:start position:0% +the area is 5 kons per meter squared. + + + align:start position:0% +the area is 5 kons per meter squared. +And in this case, we're told that the + + align:start position:0% +And in this case, we're told that the + + + align:start position:0% +And in this case, we're told that the +foam is going to be a flexible + + align:start position:0% +foam is going to be a flexible + + + align:start position:0% +foam is going to be a flexible +polyurethane and it has a solid modulus + + align:start position:0% +polyurethane and it has a solid modulus + + + align:start position:0% +polyurethane and it has a solid modulus +of 50 megapascals. And so we can + + align:start position:0% +of 50 megapascals. And so we can + + + align:start position:0% +of 50 megapascals. And so we can +calculate this normalized peak stress. + + align:start position:0% +calculate this normalized peak stress. + + + align:start position:0% +calculate this normalized peak stress. +So the normalized peak stress here is + + align:start position:0% +So the normalized peak stress here is + + + align:start position:0% +So the normalized peak stress here is +10us4. + + align:start position:0% +10us4. + + + align:start position:0% +10us4. +So in this pro problem here, we need to + + align:start position:0% +So in this pro problem here, we need to + + + align:start position:0% +So in this pro problem here, we need to +figure out what's the foam density and + + align:start position:0% +figure out what's the foam density and + + + align:start position:0% +figure out what's the foam density and +what's the thickness of the foam to + + align:start position:0% +what's the thickness of the foam to + + + align:start position:0% +what's the thickness of the foam to +protect the object. And um so that the + + align:start position:0% +protect the object. And um so that the + + + align:start position:0% +protect the object. And um so that the +last slide is just sum summarized here. + + align:start position:0% +last slide is just sum summarized here. + + + align:start position:0% +last slide is just sum summarized here. +And I realized that when I was going to + + align:start position:0% +And I realized that when I was going to + + + align:start position:0% +And I realized that when I was going to +put this up, the font is going to be + + align:start position:0% +put this up, the font is going to be + + + align:start position:0% +put this up, the font is going to be +kind of small. So I blew it up a little. + + align:start position:0% +kind of small. So I blew it up a little. + + + align:start position:0% +kind of small. So I blew it up a little. +So we have figured out that we're at + + align:start position:0% +So we have figured out that we're at + + + align:start position:0% +So we have figured out that we're at +sigma P over ES. The peak stress + + align:start position:0% +sigma P over ES. The peak stress + + + align:start position:0% +sigma P over ES. The peak stress +normalized by the solid modulus is 10 + + align:start position:0% +normalized by the solid modulus is 10 + + + align:start position:0% +normalized by the solid modulus is 10 +the minus 4. And we know that we're + + align:start position:0% +the minus 4. And we know that we're + + + align:start position:0% +the minus 4. And we know that we're +going to use a flexible elastoic + + align:start position:0% +going to use a flexible elastoic + + + align:start position:0% +going to use a flexible elastoic +polyurethane. So we pull out our diagram + + align:start position:0% +polyurethane. So we pull out our diagram + + + align:start position:0% +polyurethane. So we pull out our diagram +for elastoic foams. And this sort of + + align:start position:0% +for elastoic foams. And this sort of + + + align:start position:0% +for elastoic foams. And this sort of +hashed band here corresponds to all the + + align:start position:0% +hashed band here corresponds to all the + + + align:start position:0% +hashed band here corresponds to all the +different strain rates and all the + + align:start position:0% +different strain rates and all the + + + align:start position:0% +different strain rates and all the +different densities. So I haven't + + align:start position:0% +different densities. So I haven't + + + align:start position:0% +different densities. So I haven't +plotted each individual line. We've just + + align:start position:0% +plotted each individual line. We've just + + + align:start position:0% +plotted each individual line. We've just +got this kind of band that represents + + align:start position:0% +got this kind of band that represents + + + align:start position:0% +got this kind of band that represents +the whole thing. So we know that our + + align:start position:0% +the whole thing. So we know that our + + + align:start position:0% +the whole thing. So we know that our +normalized peak stress is going to be + + align:start position:0% +normalized peak stress is going to be + + + align:start position:0% +normalized peak stress is going to be +somewhere along this line here. Okay, + + align:start position:0% +somewhere along this line here. Okay, + + + align:start position:0% +somewhere along this line here. Okay, +that's that's from everything that's + + align:start position:0% +that's that's from everything that's + + + align:start position:0% +that's that's from everything that's +given and what we can calculate. And we + + align:start position:0% +given and what we can calculate. And we + + + align:start position:0% +given and what we can calculate. And we +want to know what density of foam to use + + align:start position:0% +want to know what density of foam to use + + + align:start position:0% +want to know what density of foam to use +and what thickness. So the way you + + align:start position:0% +and what thickness. So the way you + + + align:start position:0% +and what thickness. So the way you +approach this is the thickness is going + + align:start position:0% +approach this is the thickness is going + + + align:start position:0% +approach this is the thickness is going +to affect the strain rate. So the strain + + align:start position:0% +to affect the strain rate. So the strain + + + align:start position:0% +to affect the strain rate. So the strain +rate is just going to be the velocity on + + align:start position:0% +rate is just going to be the velocity on + + + align:start position:0% +rate is just going to be the velocity on +impact divided by the thickness or it's + + align:start position:0% +impact divided by the thickness or it's + + + align:start position:0% +impact divided by the thickness or it's +an approximation for the strain rate. So + + align:start position:0% +an approximation for the strain rate. So + + + align:start position:0% +an approximation for the strain rate. So +we don't know if we're sort of at this + + align:start position:0% +we don't know if we're sort of at this + + + align:start position:0% +we don't know if we're sort of at this +point down here or if we're at this + + align:start position:0% +point down here or if we're at this + + + align:start position:0% +point down here or if we're at this +point up there because we don't know + + align:start position:0% +point up there because we don't know + + + align:start position:0% +point up there because we don't know +where we are in the strain rate end of + + align:start position:0% +where we are in the strain rate end of + + + align:start position:0% +where we are in the strain rate end of +things. So the way you solve this is you + + align:start position:0% +things. So the way you solve this is you + + + align:start position:0% +things. So the way you solve this is you +just guess a thickness. And if you guess + + align:start position:0% +just guess a thickness. And if you guess + + + align:start position:0% +just guess a thickness. And if you guess +a thickness, you can calculate a strain + + align:start position:0% +a thickness, you can calculate a strain + + + align:start position:0% +a thickness, you can calculate a strain +rate. Then if you calculate the strain + + align:start position:0% +rate. Then if you calculate the strain + + + align:start position:0% +rate. Then if you calculate the strain +rate, you know where in this band you + + align:start position:0% +rate, you know where in this band you + + + align:start position:0% +rate, you know where in this band you +are. You can figure out a value of w + + align:start position:0% +are. You can figure out a value of w + + + align:start position:0% +are. You can figure out a value of w +over es. And you can use an iterative + + align:start position:0% +over es. And you can use an iterative + + + align:start position:0% +over es. And you can use an iterative +process. And the way this is set up is + + align:start position:0% +process. And the way this is set up is + + + align:start position:0% +process. And the way this is set up is +we've chosen two very different initial + + align:start position:0% +we've chosen two very different initial + + + align:start position:0% +we've chosen two very different initial +thicknesses. And the point of doing that + + align:start position:0% +thicknesses. And the point of doing that + + + align:start position:0% +thicknesses. And the point of doing that +is to show you that it converges very + + align:start position:0% +is to show you that it converges very + + + align:start position:0% +is to show you that it converges very +quickly. So the first iteration on this + + align:start position:0% +quickly. So the first iteration on this + + + align:start position:0% +quickly. So the first iteration on this +side here, we've chosen a thickness of a + + align:start position:0% +side here, we've chosen a thickness of a + + + align:start position:0% +side here, we've chosen a thickness of a +meter, which is probably unlikely that + + align:start position:0% +meter, which is probably unlikely that + + + align:start position:0% +meter, which is probably unlikely that +we need a meter of foam. And on this + + align:start position:0% +we need a meter of foam. And on this + + + align:start position:0% +we need a meter of foam. And on this +side here, we've chosen a millimeter, + + align:start position:0% +side here, we've chosen a millimeter, + + + align:start position:0% +side here, we've chosen a millimeter, +0.001 meters. So probably we need more + + align:start position:0% +0.001 meters. So probably we need more + + + align:start position:0% +0.001 meters. So probably we need more +than that. So we probably need to be + + align:start position:0% +than that. So we probably need to be + + + align:start position:0% +than that. So we probably need to be +somewhere between those two bounds. So + + align:start position:0% +somewhere between those two bounds. So + + + align:start position:0% +somewhere between those two bounds. So +if the thickness was a meter, then the + + align:start position:0% +if the thickness was a meter, then the + + + align:start position:0% +if the thickness was a meter, then the +strain rate turns out to be 4.5 per + + align:start position:0% +strain rate turns out to be 4.5 per + + + align:start position:0% +strain rate turns out to be 4.5 per +second. And then we know where we are on + + align:start position:0% +second. And then we know where we are on + + + align:start position:0% +second. And then we know where we are on +this diagram. And we can read off a + + align:start position:0% +this diagram. And we can read off a + + + align:start position:0% +this diagram. And we can read off a +value of W over ES. So we know we're on + + align:start position:0% +value of W over ES. So we know we're on + + + align:start position:0% +value of W over ES. So we know we're on +this line here. And for a particular + + align:start position:0% +this line here. And for a particular + + + align:start position:0% +this line here. And for a particular +strain rate, we can read off the W over + + align:start position:0% +strain rate, we can read off the W over + + + align:start position:0% +strain rate, we can read off the W over +ES. So here's the value 5.25* 10us 5. + + align:start position:0% +ES. So here's the value 5.25* 10us 5. + + + align:start position:0% +ES. So here's the value 5.25* 10us 5. +And if we know ES which we do, we can + + align:start position:0% +And if we know ES which we do, we can + + + align:start position:0% +And if we know ES which we do, we can +then u calculate the actual energy + + align:start position:0% +then u calculate the actual energy + + + align:start position:0% +then u calculate the actual energy +absorbed per unit volume and get W. So + + align:start position:0% +absorbed per unit volume and get W. So + + + align:start position:0% +absorbed per unit volume and get W. So +W's 2620 JUW per cubic meter and we can + + align:start position:0% +W's 2620 JUW per cubic meter and we can + + + align:start position:0% +W's 2620 JUW per cubic meter and we can +use that value that's an energy per unit + + align:start position:0% +use that value that's an energy per unit + + + align:start position:0% +use that value that's an energy per unit +volume. We know the area of contact and + + align:start position:0% +volume. We know the area of contact and + + + align:start position:0% +volume. We know the area of contact and +we can use that to get another value of + + align:start position:0% +we can use that to get another value of + + + align:start position:0% +we can use that to get another value of +the thickness. So we we use that to + + align:start position:0% +the thickness. So we we use that to + + + align:start position:0% +the thickness. So we we use that to +calculate the next iteration of the + + align:start position:0% +calculate the next iteration of the + + + align:start position:0% +calculate the next iteration of the +thickness. So U is the total energy in + + align:start position:0% +thickness. So U is the total energy in + + + align:start position:0% +thickness. So U is the total energy in +jewels and W is the energy per unit + + align:start position:0% +jewels and W is the energy per unit + + + align:start position:0% +jewels and W is the energy per unit +volume. So u the energy in jewels is + + align:start position:0% +volume. So u the energy in jewels is + + + align:start position:0% +volume. So u the energy in jewels is +going to equal the energy unit volume + + align:start position:0% +going to equal the energy unit volume + + + align:start position:0% +going to equal the energy unit volume +time the area time the thickness. So we + + align:start position:0% +time the area time the thickness. So we + + + align:start position:0% +time the area time the thickness. So we +know what the area is 2. We can then + + align:start position:0% +know what the area is 2. We can then + + + align:start position:0% +know what the area is 2. We can then +calculate a new thickness. So now our + + align:start position:0% +calculate a new thickness. So now our + + + align:start position:0% +calculate a new thickness. So now our +new thickness is.19 m. We can use that + + align:start position:0% +new thickness is.19 m. We can use that + + + align:start position:0% +new thickness is.19 m. We can use that +to get a new strain rate that's 24/ + + align:start position:0% +to get a new strain rate that's 24/ + + + align:start position:0% +to get a new strain rate that's 24/ +And go through the whole thing again and + + align:start position:0% +And go through the whole thing again and + + + align:start position:0% +And go through the whole thing again and +we end up with a revised energy of 3300 + + align:start position:0% +we end up with a revised energy of 3300 + + + align:start position:0% +we end up with a revised energy of 3300 +jew peric meter. Now if we started at + + align:start position:0% +jew peric meter. Now if we started at + + + align:start position:0% +jew peric meter. Now if we started at +the other end if we started with the + + align:start position:0% +the other end if we started with the + + + align:start position:0% +the other end if we started with the +first guess was a millimeter + + align:start position:0% +first guess was a millimeter + + + align:start position:0% +first guess was a millimeter +then the strain rate is 4.5 * 10us 3/s + + align:start position:0% +then the strain rate is 4.5 * 10us 3/s + + + align:start position:0% +then the strain rate is 4.5 * 10us 3/s +uh that gives us a different value that + + align:start position:0% +uh that gives us a different value that + + + align:start position:0% +uh that gives us a different value that +we read off here for w over es and a + + align:start position:0% +we read off here for w over es and a + + + align:start position:0% +we read off here for w over es and a +different value for w and then we use + + align:start position:0% +different value for w and then we use + + + align:start position:0% +different value for w and then we use +this value here for w to make another + + align:start position:0% +this value here for w to make another + + + align:start position:0% +this value here for w to make another +guess for the thickness. So that value + + align:start position:0% +guess for the thickness. So that value + + + align:start position:0% +guess for the thickness. So that value +is 0.14. And then we go through the + + align:start position:0% +is 0.14. And then we go through the + + + align:start position:0% +is 0.14. And then we go through the +whole thing again. We get a revised + + align:start position:0% +whole thing again. We get a revised + + + align:start position:0% +whole thing again. We get a revised +strain rate, a revised W over ES and a + + align:start position:0% +strain rate, a revised W over ES and a + + + align:start position:0% +strain rate, a revised W over ES and a +revised W. And you can see after just + + align:start position:0% +revised W. And you can see after just + + + align:start position:0% +revised W. And you can see after just +two iterations, these two things are + + align:start position:0% +two iterations, these two things are + + + align:start position:0% +two iterations, these two things are +almost exactly the same. And then on the + + align:start position:0% +almost exactly the same. And then on the + + + align:start position:0% +almost exactly the same. And then on the +third iteration, they both would give + + align:start position:0% +third iteration, they both would give + + + align:start position:0% +third iteration, they both would give +you a thickness of 0.15 m. Okay? So even + + align:start position:0% +you a thickness of 0.15 m. Okay? So even + + + align:start position:0% +you a thickness of 0.15 m. Okay? So even +though you can pick, you know, wildly + + align:start position:0% +though you can pick, you know, wildly + + + align:start position:0% +though you can pick, you know, wildly +wrong first iterations, it it converges + + align:start position:0% +wrong first iterations, it it converges + + + align:start position:0% +wrong first iterations, it it converges +very quickly. And it's sort of a fairly + + align:start position:0% +very quickly. And it's sort of a fairly + + + align:start position:0% +very quickly. And it's sort of a fairly +simple calculation to do. Um so you know + + align:start position:0% +simple calculation to do. Um so you know + + + align:start position:0% +simple calculation to do. Um so you know +the thickness that you want is in here + + align:start position:0% +the thickness that you want is in here + + + align:start position:0% +the thickness that you want is in here +and then you can get the optimum density + + align:start position:0% +and then you can get the optimum density + + + align:start position:0% +and then you can get the optimum density +here. So you know uh that your sigma P + + align:start position:0% +here. So you know uh that your sigma P + + + align:start position:0% +here. So you know uh that your sigma P +over ES is along this line of 10us 4 + + align:start position:0% +over ES is along this line of 10us 4 + + + align:start position:0% +over ES is along this line of 10us 4 +were somewhere in here. Uh these two + + align:start position:0% +were somewhere in here. Uh these two + + + align:start position:0% +were somewhere in here. Uh these two +strain rates here one was 24 one was 32. + + align:start position:0% +strain rates here one was 24 one was 32. + + + align:start position:0% +strain rates here one was 24 one was 32. +So the the final value is going to be + + align:start position:0% +So the the final value is going to be + + + align:start position:0% +So the the final value is going to be +somewhere around 30. And if you look on + + align:start position:0% +somewhere around 30. And if you look on + + + align:start position:0% +somewhere around 30. And if you look on +this thing here you can see there's a + + align:start position:0% +this thing here you can see there's a + + + align:start position:0% +this thing here you can see there's a +line that corresponds to 10 there's a + + align:start position:0% +line that corresponds to 10 there's a + + + align:start position:0% +line that corresponds to 10 there's a +line that corresponds to 100. We're + + align:start position:0% +line that corresponds to 100. We're + + + align:start position:0% +line that corresponds to 100. We're +going to be right around in there. So + + align:start position:0% +going to be right around in there. So + + + align:start position:0% +going to be right around in there. So +the relative density is going to be + + align:start position:0% +the relative density is going to be + + + align:start position:0% +the relative density is going to be +right around 0.01. Okay. So you can use + + align:start position:0% +right around 0.01. Okay. So you can use + + + align:start position:0% +right around 0.01. Okay. So you can use +the diagram to get the thickness and to + + align:start position:0% +the diagram to get the thickness and to + + + align:start position:0% +the diagram to get the thickness and to +get the density. Okay. Are we good? + + align:start position:0% +get the density. Okay. Are we good? + + + align:start position:0% +get the density. Okay. Are we good? +We're good. Okay. Um so I've written + + align:start position:0% +We're good. Okay. Um so I've written + + + align:start position:0% +We're good. Okay. Um so I've written +some notes and I'll just scan those and + + align:start position:0% +some notes and I'll just scan those and + + + align:start position:0% +some notes and I'll just scan those and +I'll put them in the stellar site. + + align:start position:0% +I'll put them in the stellar site. + + + align:start position:0% +I'll put them in the stellar site. +Uh so here's another example here. And + + align:start position:0% +Uh so here's another example here. And + + + align:start position:0% +Uh so here's another example here. And +in this example it's set up a little bit + + align:start position:0% +in this example it's set up a little bit + + + align:start position:0% +in this example it's set up a little bit +differently. So in this example here, uh + + align:start position:0% +differently. So in this example here, uh + + + align:start position:0% +differently. So in this example here, uh +we're not told the material, but we're + + align:start position:0% +we're not told the material, but we're + + + align:start position:0% +we're not told the material, but we're +told the thickness of the foam. So this + + align:start position:0% +told the thickness of the foam. So this + + + align:start position:0% +told the thickness of the foam. So this +time we want to get the material and we + + align:start position:0% +time we want to get the material and we + + + align:start position:0% +time we want to get the material and we +want to get the density of the foam. So + + align:start position:0% +want to get the density of the foam. So + + + align:start position:0% +want to get the density of the foam. So +here we've got um the specification. + + align:start position:0% +here we've got um the specification. + + + align:start position:0% +here we've got um the specification. +We're told the mass is 2 1/2 kg. The + + align:start position:0% +We're told the mass is 2 1/2 kg. The + + + align:start position:0% +We're told the mass is 2 1/2 kg. The +area of contact is 0025 m squared. We're + + align:start position:0% +area of contact is 0025 m squared. We're + + + align:start position:0% +area of contact is 0025 m squared. We're +told the thickness here. The thickness + + align:start position:0% +told the thickness here. The thickness + + + align:start position:0% +told the thickness here. The thickness +is 20 mm. We've got a drop height of 1 + + align:start position:0% +is 20 mm. We've got a drop height of 1 + + + align:start position:0% +is 20 mm. We've got a drop height of 1 +meter again. The velocity of impact is + + align:start position:0% +meter again. The velocity of impact is + + + align:start position:0% +meter again. The velocity of impact is +then going to be 4.5 m/s again. And + + align:start position:0% +then going to be 4.5 m/s again. And + + + align:start position:0% +then going to be 4.5 m/s again. And +since we know t, we know that the strain + + align:start position:0% +since we know t, we know that the strain + + + align:start position:0% +since we know t, we know that the strain +rate is going to be around 225 per + + align:start position:0% +rate is going to be around 225 per + + + align:start position:0% +rate is going to be around 225 per +second. Okay. + + align:start position:0% +second. Okay. + + + align:start position:0% +second. Okay. +Uh we can calculate the energy absorbed + + align:start position:0% +Uh we can calculate the energy absorbed + + + align:start position:0% +Uh we can calculate the energy absorbed +mgh uh 25 jewels. Uh we can calculate + + align:start position:0% +mgh uh 25 jewels. Uh we can calculate + + + align:start position:0% +mgh uh 25 jewels. Uh we can calculate +the energy absorbed per unit volume + + align:start position:0% +the energy absorbed per unit volume + + + align:start position:0% +the energy absorbed per unit volume +because we've got the area and the + + align:start position:0% +because we've got the area and the + + + align:start position:0% +because we've got the area and the +thickness. So we just divide that by the + + align:start position:0% +thickness. So we just divide that by the + + + align:start position:0% +thickness. So we just divide that by the +area and the thickness. And we have 5 or + + align:start position:0% +area and the thickness. And we have 5 or + + + align:start position:0% +area and the thickness. And we have 5 or +5 * 10 4th jewels per cubic meter. And + + align:start position:0% +5 * 10 4th jewels per cubic meter. And + + + align:start position:0% +5 * 10 4th jewels per cubic meter. And +we're told that we're supposed to design + + align:start position:0% +we're told that we're supposed to design + + + align:start position:0% +we're told that we're supposed to design +it so the package can withstand a + + align:start position:0% +it so the package can withstand a + + + align:start position:0% +it so the package can withstand a +deceleration of 100 g. And so that gives + + align:start position:0% +deceleration of 100 g. And so that gives + + + align:start position:0% +deceleration of 100 g. And so that gives +you a maximum force. And here we've got + + align:start position:0% +you a maximum force. And here we've got + + + align:start position:0% +you a maximum force. And here we've got +a maximum allowable peak stress of 10 5 + + align:start position:0% +a maximum allowable peak stress of 10 5 + + + align:start position:0% +a maximum allowable peak stress of 10 5 +newtons per meter squared. So here we + + align:start position:0% +newtons per meter squared. So here we + + + align:start position:0% +newtons per meter squared. So here we +have our curve for the elastic foams. + + align:start position:0% +have our curve for the elastic foams. + + + align:start position:0% +have our curve for the elastic foams. +Again, let's assume it's going to be an + + align:start position:0% +Again, let's assume it's going to be an + + + align:start position:0% +Again, let's assume it's going to be an +elastic foam, but we don't know what + + align:start position:0% +elastic foam, but we don't know what + + + align:start position:0% +elastic foam, but we don't know what +kind of foam. + + align:start position:0% +kind of foam. + + + align:start position:0% +kind of foam. +So the way you solve this problem is + + align:start position:0% +So the way you solve this problem is + + + align:start position:0% +So the way you solve this problem is +that you make a guess for what ES is. So + + align:start position:0% +that you make a guess for what ES is. So + + + align:start position:0% +that you make a guess for what ES is. So +remember these diagrams are all + + align:start position:0% +remember these diagrams are all + + + align:start position:0% +remember these diagrams are all +normalized by ES. So to plot a point on + + align:start position:0% +normalized by ES. So to plot a point on + + + align:start position:0% +normalized by ES. So to plot a point on +there, we need to know what ES is. So + + align:start position:0% +there, we need to know what ES is. So + + + align:start position:0% +there, we need to know what ES is. So +here we're going to make a guess and + + align:start position:0% +here we're going to make a guess and + + + align:start position:0% +here we're going to make a guess and +we're going to assume that ES is 100 + + align:start position:0% +we're going to assume that ES is 100 + + + align:start position:0% +we're going to assume that ES is 100 +megapascals to start. And if we had that + + align:start position:0% +megapascals to start. And if we had that + + + align:start position:0% +megapascals to start. And if we had that +value of ES, we know W up here and we + + align:start position:0% +value of ES, we know W up here and we + + + align:start position:0% +value of ES, we know W up here and we +know sigma P there. So we just divide + + align:start position:0% +know sigma P there. So we just divide + + + align:start position:0% +know sigma P there. So we just divide +those values of W and sigma P by ES and + + align:start position:0% +those values of W and sigma P by ES and + + + align:start position:0% +those values of W and sigma P by ES and +we get these two values here and we plot + + align:start position:0% +we get these two values here and we plot + + + align:start position:0% +we get these two values here and we plot +those two values on the thing here. So + + align:start position:0% +those two values on the thing here. So + + + align:start position:0% +those two values on the thing here. So +here's our point A and that corresponds + + align:start position:0% +here's our point A and that corresponds + + + align:start position:0% +here's our point A and that corresponds +to that first guess of 100 megapascals + + align:start position:0% +to that first guess of 100 megapascals + + + align:start position:0% +to that first guess of 100 megapascals +for the modulus of the solid. So that's + + align:start position:0% +for the modulus of the solid. So that's + + + align:start position:0% +for the modulus of the solid. So that's +that's not necessarily the final answer. + + align:start position:0% +that's not necessarily the final answer. + + + align:start position:0% +that's not necessarily the final answer. +That's not the right answer. That's just + + align:start position:0% +That's not the right answer. That's just + + + align:start position:0% +That's not the right answer. That's just +somewhere to start. So the thing to + + align:start position:0% +somewhere to start. So the thing to + + + align:start position:0% +somewhere to start. So the thing to +notice is if we have that point there, + + align:start position:0% +notice is if we have that point there, + + + align:start position:0% +notice is if we have that point there, +um the strain rate there is probably not + + align:start position:0% +um the strain rate there is probably not + + + align:start position:0% +um the strain rate there is probably not +quite right. This upper bound here is um + + align:start position:0% +quite right. This upper bound here is um + + + align:start position:0% +quite right. This upper bound here is um +let's see got to get closer. Oh, let's + + align:start position:0% +let's see got to get closer. Oh, let's + + + align:start position:0% +let's see got to get closer. Oh, let's +see. That's 10 to the minus two. That's + + align:start position:0% +see. That's 10 to the minus two. That's + + + align:start position:0% +see. That's 10 to the minus two. That's +10 to the two. So the strain rate we + + align:start position:0% +10 to the two. So the strain rate we + + + align:start position:0% +10 to the two. So the strain rate we +want to be is closer up to here. It's + + align:start position:0% +want to be is closer up to here. It's + + + align:start position:0% +want to be is closer up to here. It's +not quite down there. Um, so we're not + + align:start position:0% +not quite down there. Um, so we're not + + + align:start position:0% +not quite down there. Um, so we're not +at the right strain rate. But the thing + + align:start position:0% +at the right strain rate. But the thing + + + align:start position:0% +at the right strain rate. But the thing +to notice is that if we draw a line of + + align:start position:0% +to notice is that if we draw a line of + + + align:start position:0% +to notice is that if we draw a line of +slope one, so there's this dashed line + + align:start position:0% +slope one, so there's this dashed line + + + align:start position:0% +slope one, so there's this dashed line +of slope one. When we move up and down + + align:start position:0% +of slope one. When we move up and down + + + align:start position:0% +of slope one. When we move up and down +that line, we're just changing ES, + + align:start position:0% +that line, we're just changing ES, + + + align:start position:0% +that line, we're just changing ES, +right? Because everything's normalized + + align:start position:0% +right? Because everything's normalized + + + align:start position:0% +right? Because everything's normalized +with respect to ES. If that line has a + + align:start position:0% +with respect to ES. If that line has a + + + align:start position:0% +with respect to ES. If that line has a +slope of one, then we're just kind of + + align:start position:0% +slope of one, then we're just kind of + + + align:start position:0% +slope of one, then we're just kind of +moving up and down with respect to ES. + + align:start position:0% +moving up and down with respect to ES. + + + align:start position:0% +moving up and down with respect to ES. +So what we do is we scoot up the line to + + align:start position:0% +So what we do is we scoot up the line to + + + align:start position:0% +So what we do is we scoot up the line to +get to the point that's on the uh right + + align:start position:0% +get to the point that's on the uh right + + + align:start position:0% +get to the point that's on the uh right +strain rate. So if this is a strain rate + + align:start position:0% +strain rate. So if this is a strain rate + + + align:start position:0% +strain rate. So if this is a strain rate +of 100 or around 200, we want to be at + + align:start position:0% +of 100 or around 200, we want to be at + + + align:start position:0% +of 100 or around 200, we want to be at +point B. And then from point B, we can + + align:start position:0% +point B. And then from point B, we can + + + align:start position:0% +point B. And then from point B, we can +read off what's the value of W over ES + + align:start position:0% +read off what's the value of W over ES + + + align:start position:0% +read off what's the value of W over ES +and sigma P over ES. And from that, we + + align:start position:0% +and sigma P over ES. And from that, we + + + align:start position:0% +and sigma P over ES. And from that, we +can back out what the solid modulus we + + align:start position:0% +can back out what the solid modulus we + + + align:start position:0% +can back out what the solid modulus we +want is. So these are the values that we + + align:start position:0% +want is. So these are the values that we + + + align:start position:0% +want is. So these are the values that we +read off the chart. This gives us an ES + + align:start position:0% +read off the chart. This gives us an ES + + + align:start position:0% +read off the chart. This gives us an ES +of 28 megapascals. And again, you can go + + align:start position:0% +of 28 megapascals. And again, you can go + + + align:start position:0% +of 28 megapascals. And again, you can go +to this more detailed diagram here. And + + align:start position:0% +to this more detailed diagram here. And + + + align:start position:0% +to this more detailed diagram here. And +if you read off the sigma P over ES and + + align:start position:0% +if you read off the sigma P over ES and + + + align:start position:0% +if you read off the sigma P over ES and +the W over E S, the density you want is + + align:start position:0% +the W over E S, the density you want is + + + align:start position:0% +the W over E S, the density you want is +about 0.1. So it tells you the modulus + + align:start position:0% +about 0.1. So it tells you the modulus + + + align:start position:0% +about 0.1. So it tells you the modulus +of the solid and from that you can pick + + align:start position:0% +of the solid and from that you can pick + + + align:start position:0% +of the solid and from that you can pick +a solid and it tells you the density. + + align:start position:0% +a solid and it tells you the density. + + + align:start position:0% +a solid and it tells you the density. +Okay. Are we good? No. Okay. So I have + + align:start position:0% +Okay. Are we good? No. Okay. So I have + + + align:start position:0% +Okay. Are we good? No. Okay. So I have +one more. So there's there's a slightly + + align:start position:0% +one more. So there's there's a slightly + + + align:start position:0% +one more. So there's there's a slightly +different way you can do it too. Um so + + align:start position:0% +different way you can do it too. Um so + + + align:start position:0% +different way you can do it too. Um so +now I want to talk about bicycle + + align:start position:0% +now I want to talk about bicycle + + + align:start position:0% +now I want to talk about bicycle +helmets. Who's not you're my bicycle + + align:start position:0% +helmets. Who's not you're my bicycle + + + align:start position:0% +helmets. Who's not you're my bicycle +helmet person? + + align:start position:0% +helmet person? + + + align:start position:0% +helmet person? +So um so this is another little case + + align:start position:0% +So um so this is another little case + + + align:start position:0% +So um so this is another little case +study that involves a slightly different + + align:start position:0% +study that involves a slightly different + + + align:start position:0% +study that involves a slightly different +way to do this. Uh, and this involves a + + align:start position:0% +way to do this. Uh, and this involves a + + + align:start position:0% +way to do this. Uh, and this involves a +slightly different diagram. So, the idea + + align:start position:0% +slightly different diagram. So, the idea + + + align:start position:0% +slightly different diagram. So, the idea +here is to choose a material for a + + align:start position:0% +here is to choose a material for a + + + align:start position:0% +here is to choose a material for a +bicycle helmet. And as you probably all + + align:start position:0% +bicycle helmet. And as you probably all + + + align:start position:0% +bicycle helmet. And as you probably all +know, the bicycle helmets have a hard + + align:start position:0% +know, the bicycle helmets have a hard + + + align:start position:0% +know, the bicycle helmets have a hard +shell and they have some sort of foamy + + align:start position:0% +shell and they have some sort of foamy + + + align:start position:0% +shell and they have some sort of foamy +liner. And the foam's usually around 20 + + align:start position:0% +liner. And the foam's usually around 20 + + + align:start position:0% +liner. And the foam's usually around 20 +mm thick. And you want something that's + + align:start position:0% +mm thick. And you want something that's + + + align:start position:0% +mm thick. And you want something that's +light because you don't want your helmet + + align:start position:0% +light because you don't want your helmet + + + align:start position:0% +light because you don't want your helmet +to be too heavy, but you want something + + align:start position:0% +to be too heavy, but you want something + + + align:start position:0% +to be too heavy, but you want something +that'll absorb the energy from the + + align:start position:0% +that'll absorb the energy from the + + + align:start position:0% +that'll absorb the energy from the +impact. So, um, I've set this up here. + + align:start position:0% +impact. So, um, I've set this up here. + + + align:start position:0% +impact. So, um, I've set this up here. +So we assume the mass of the head is + + align:start position:0% +So we assume the mass of the head is + + + align:start position:0% +So we assume the mass of the head is +about 3 kg and we assume that it could + + align:start position:0% +about 3 kg and we assume that it could + + + align:start position:0% +about 3 kg and we assume that it could +withstand a deceleration of something + + align:start position:0% +withstand a deceleration of something + + + align:start position:0% +withstand a deceleration of something +like 300g. + + align:start position:0% +like 300g. + + + align:start position:0% +like 300g. +And so then you can get a force mass + + align:start position:0% +And so then you can get a force mass + + + align:start position:0% +And so then you can get a force mass +times the acceleration gives you the + + align:start position:0% +times the acceleration gives you the + + + align:start position:0% +times the acceleration gives you the +force. And I've assumed an area of + + align:start position:0% +force. And I've assumed an area of + + + align:start position:0% +force. And I've assumed an area of +contact of something like 1.01 + + align:start position:0% +contact of something like 1.01 + + + align:start position:0% +contact of something like 1.01 +meters squared. So that gives you a peak + + align:start position:0% +meters squared. So that gives you a peak + + + align:start position:0% +meters squared. So that gives you a peak +stress. So this uh method here is based + + align:start position:0% +stress. So this uh method here is based + + + align:start position:0% +stress. So this uh method here is based +on the idea that you have these um + + align:start position:0% +on the idea that you have these um + + + align:start position:0% +on the idea that you have these um +material selection charts for foams. + + align:start position:0% +material selection charts for foams. + + + align:start position:0% +material selection charts for foams. +Remember we talked about that earlier. + + align:start position:0% +Remember we talked about that earlier. + + + align:start position:0% +Remember we talked about that earlier. +And this is the compressive stress at + + align:start position:0% +And this is the compressive stress at + + + align:start position:0% +And this is the compressive stress at +25% strain. So the idea is that axis + + align:start position:0% +25% strain. So the idea is that axis + + + align:start position:0% +25% strain. So the idea is that axis +there is meant to represent the plateau + + align:start position:0% +there is meant to represent the plateau + + + align:start position:0% +there is meant to represent the plateau +stress. And this axis here represents + + align:start position:0% +stress. And this axis here represents + + + align:start position:0% +stress. And this axis here represents +the densification strain. And these + + align:start position:0% +the densification strain. And these + + + align:start position:0% +the densification strain. And these +dashed lines here correspond to + + align:start position:0% +dashed lines here correspond to + + + align:start position:0% +dashed lines here correspond to +basically a value of w an energy + + align:start position:0% +basically a value of w an energy + + + align:start position:0% +basically a value of w an energy +absorbed per unit volume. So this is an + + align:start position:0% +absorbed per unit volume. So this is an + + + align:start position:0% +absorbed per unit volume. So this is an +energy absorbed per unit volume of 0.01 + + align:start position:0% +energy absorbed per unit volume of 0.01 + + + align:start position:0% +energy absorbed per unit volume of 0.01 +mega per cubic meter 0.01 and so on. + + align:start position:0% +mega per cubic meter 0.01 and so on. + + + align:start position:0% +mega per cubic meter 0.01 and so on. +So if you know the uh peak stress that + + align:start position:0% +So if you know the uh peak stress that + + + align:start position:0% +So if you know the uh peak stress that +you can tolerate uh for the numbers I + + align:start position:0% +you can tolerate uh for the numbers I + + + align:start position:0% +you can tolerate uh for the numbers I +gave you it works out to be 0.9 + + align:start position:0% +gave you it works out to be 0.9 + + + align:start position:0% +gave you it works out to be 0.9 +megapascals. So here is just a little + + align:start position:0% +megapascals. So here is just a little + + + align:start position:0% +megapascals. So here is just a little +less than one. So that's the peak stress + + align:start position:0% +less than one. So that's the peak stress + + + align:start position:0% +less than one. So that's the peak stress +that you can tolerate there. And uh you + + align:start position:0% +that you can tolerate there. And uh you + + + align:start position:0% +that you can tolerate there. And uh you +can see that the material that's going + + align:start position:0% +can see that the material that's going + + + align:start position:0% +can see that the material that's going +to absorb the most energy. So you're + + align:start position:0% +to absorb the most energy. So you're + + + align:start position:0% +to absorb the most energy. So you're +absorbing more energy as you move over + + align:start position:0% +absorbing more energy as you move over + + + align:start position:0% +absorbing more energy as you move over +kind of this way on the curve um on the + + align:start position:0% +kind of this way on the curve um on the + + + align:start position:0% +kind of this way on the curve um on the +plot. So the material that's going to do + + align:start position:0% +plot. So the material that's going to do + + + align:start position:0% +plot. So the material that's going to do +the best is something like an expanded + + align:start position:0% +the best is something like an expanded + + + align:start position:0% +the best is something like an expanded +polystyrene that's 5% dense. So I've + + align:start position:0% +polystyrene that's 5% dense. So I've + + + align:start position:0% +polystyrene that's 5% dense. So I've +highlighted that in red. Expanded + + align:start position:0% +highlighted that in red. Expanded + + + align:start position:0% +highlighted that in red. Expanded +polystyrene that's 5% dense. And then + + align:start position:0% +polystyrene that's 5% dense. And then + + + align:start position:0% +polystyrene that's 5% dense. And then +this is the the densification strain + + align:start position:0% +this is the the densification strain + + + align:start position:0% +this is the the densification strain +here. And you know the the the lines of + + align:start position:0% +here. And you know the the the lines of + + + align:start position:0% +here. And you know the the the lines of +the energy absorption are just the + + align:start position:0% +the energy absorption are just the + + + align:start position:0% +the energy absorption are just the +stress times the strain. So you can + + align:start position:0% +stress times the strain. So you can + + + align:start position:0% +stress times the strain. So you can +basically just read off from here that + + align:start position:0% +basically just read off from here that + + + align:start position:0% +basically just read off from here that +expanded polystyrene that was 5% dense + + align:start position:0% +expanded polystyrene that was 5% dense + + + align:start position:0% +expanded polystyrene that was 5% dense +would be a good choice for a bicycle + + align:start position:0% +would be a good choice for a bicycle + + + align:start position:0% +would be a good choice for a bicycle +helmet foam. Okay. Would you like to add + + align:start position:0% +helmet foam. Okay. Would you like to add + + + align:start position:0% +helmet foam. Okay. Would you like to add +anything about bicycle helmet foams? + + align:start position:0% +anything about bicycle helmet foams? + + + align:start position:0% +anything about bicycle helmet foams? +Exactly what they use. + + align:start position:0% +Exactly what they use. + + + align:start position:0% +Exactly what they use. +I think that is exactly what they use. + + align:start position:0% +I think that is exactly what they use. + + + align:start position:0% +I think that is exactly what they use. +Yes. So um so this is just another way + + align:start position:0% +Yes. So um so this is just another way + + + align:start position:0% +Yes. So um so this is just another way +to do this kind of thing. And I did one + + align:start position:0% +to do this kind of thing. And I did one + + + align:start position:0% +to do this kind of thing. And I did one +more little calculation here. You can if + + align:start position:0% +more little calculation here. You can if + + + align:start position:0% +more little calculation here. You can if +you know um the thickness of the foam is + + align:start position:0% +you know um the thickness of the foam is + + + align:start position:0% +you know um the thickness of the foam is +say 20 millimeters and we've estimated + + align:start position:0% +say 20 millimeters and we've estimated + + + align:start position:0% +say 20 millimeters and we've estimated +the area of the contact. Uh you can + + align:start position:0% +the area of the contact. Uh you can + + + align:start position:0% +the area of the contact. Uh you can +figure out what the energy absorbed is + + align:start position:0% +figure out what the energy absorbed is + + + align:start position:0% +figure out what the energy absorbed is +per unit volume and from that you can + + align:start position:0% +per unit volume and from that you can + + + align:start position:0% +per unit volume and from that you can +back out the energy in terms of jewels + + align:start position:0% +back out the energy in terms of jewels + + + align:start position:0% +back out the energy in terms of jewels +and from that you can back out the the + + align:start position:0% +and from that you can back out the the + + + align:start position:0% +and from that you can back out the the +velocity. That's the maximum speed that + + align:start position:0% +velocity. That's the maximum speed that + + + align:start position:0% +velocity. That's the maximum speed that +one would want to get binged at on your + + align:start position:0% +one would want to get binged at on your + + + align:start position:0% +one would want to get binged at on your +bicycle. And the maximum speed works out + + align:start position:0% +bicycle. And the maximum speed works out + + + align:start position:0% +bicycle. And the maximum speed works out +to about 22 miles an hour. So, so that's + + align:start position:0% +to about 22 miles an hour. So, so that's + + + align:start position:0% +to about 22 miles an hour. So, so that's +just another example. Okay. Are we good? + + align:start position:0% +just another example. Okay. Are we good? + + + align:start position:0% +just another example. Okay. Are we good? +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +Yeah, exactly. Your head would be + + align:start position:0% +Yeah, exactly. Your head would be + + + align:start position:0% +Yeah, exactly. Your head would be +hitting the ground at 22 miles an hour, + + align:start position:0% +hitting the ground at 22 miles an hour, + + + align:start position:0% +hitting the ground at 22 miles an hour, +which would be ouchy. Which is why you + + align:start position:0% +which would be ouchy. Which is why you + + + align:start position:0% +which would be ouchy. Which is why you +want to wear your helmet because your + + align:start position:0% +want to wear your helmet because your + + + align:start position:0% +want to wear your helmet because your +skull will not be happy if that happens + + align:start position:0% +skull will not be happy if that happens + + + align:start position:0% +skull will not be happy if that happens +and your brain will not be happy and you + + align:start position:0% +and your brain will not be happy and you + + + align:start position:0% +and your brain will not be happy and you +will not be happy and your mom and dad + + align:start position:0% +will not be happy and your mom and dad + + + align:start position:0% +will not be happy and your mom and dad +will be really, really, really unhappy. + + align:start position:0% +will be really, really, really unhappy. + + + align:start position:0% +will be really, really, really unhappy. +So, you don't want that to happen. Okay. + + align:start position:0% +So, you don't want that to happen. Okay. + + + align:start position:0% +So, you don't want that to happen. Okay. +So, I have a few minutes left and I know + + align:start position:0% +So, I have a few minutes left and I know + + + align:start position:0% +So, I have a few minutes left and I know +I've done this for the people in 3032, + + align:start position:0% +I've done this for the people in 3032, + + + align:start position:0% +I've done this for the people in 3032, +but I was going to do by Woodpecker talk + + align:start position:0% +but I was going to do by Woodpecker talk + + + align:start position:0% +but I was going to do by Woodpecker talk +because it's about energy absorption. + + align:start position:0% +because it's about energy absorption. + + + align:start position:0% +because it's about energy absorption. +So, I mean, if you don't if you don't + + align:start position:0% +So, I mean, if you don't if you don't + + + align:start position:0% +So, I mean, if you don't if you don't +want to watch it, if you already seen + + align:start position:0% +want to watch it, if you already seen + + + align:start position:0% +want to watch it, if you already seen +it, you can go. But there's some people + + align:start position:0% +it, you can go. But there's some people + + + align:start position:0% +it, you can go. But there's some people +you guys haven't seen it and you haven't + + align:start position:0% +you guys haven't seen it and you haven't + + + align:start position:0% +you guys haven't seen it and you haven't +seen it. There's a few people haven't + + align:start position:0% +seen it. There's a few people haven't + + + align:start position:0% +seen it. There's a few people haven't +seen and it's cute. It involves birds. + + align:start position:0% +seen and it's cute. It involves birds. + + + align:start position:0% +seen and it's cute. It involves birds. +So, and it involves energy absorption. + + align:start position:0% +So, and it involves energy absorption. + + + align:start position:0% +So, and it involves energy absorption. +So, I thought I would do the woodpecker + + align:start position:0% +So, I thought I would do the woodpecker + + + align:start position:0% +So, I thought I would do the woodpecker +talk. + + align:start position:0% +talk. + + + align:start position:0% +talk. +Okay. + + align:start position:0% + + + + align:start position:0% + +So, Barry, this is all just slides. I + + align:start position:0% +So, Barry, this is all just slides. I + + + align:start position:0% +So, Barry, this is all just slides. I +don't know if you want to do the lights + + align:start position:0% +don't know if you want to do the lights + + + align:start position:0% +don't know if you want to do the lights +differently or I'm not going to write + + align:start position:0% +differently or I'm not going to write + + + align:start position:0% +differently or I'm not going to write +anything on the board. I'm just going to + + align:start position:0% +anything on the board. I'm just going to + + + align:start position:0% +anything on the board. I'm just going to +talk. + + align:start position:0% +talk. + + + align:start position:0% +talk. +Yeah. I think maybe we could turn the + + align:start position:0% +Yeah. I think maybe we could turn the + + + align:start position:0% +Yeah. I think maybe we could turn the +lights down a little, please. + + align:start position:0% + + + + align:start position:0% + +Let's try this one. + + align:start position:0% +Let's try this one. + + + align:start position:0% +Let's try this one. +Oh, there we go. That's good. Yeah. And + + align:start position:0% +Oh, there we go. That's good. Yeah. And + + + align:start position:0% +Oh, there we go. That's good. Yeah. And +I don't feel like I'm looking in the + + align:start position:0% +I don't feel like I'm looking in the + + + align:start position:0% +I don't feel like I'm looking in the +spotlight so much. That's good. Okay. + + align:start position:0% +spotlight so much. That's good. Okay. + + + align:start position:0% +spotlight so much. That's good. Okay. +So, you guys know that I like to watch + + align:start position:0% +So, you guys know that I like to watch + + + align:start position:0% +So, you guys know that I like to watch +birds. And you know that I work on + + align:start position:0% +birds. And you know that I work on + + + align:start position:0% +birds. And you know that I work on +foams. And if you look at bird books, + + align:start position:0% +foams. And if you look at bird books, + + + align:start position:0% +foams. And if you look at bird books, +sometimes the bird books say that + + align:start position:0% +sometimes the bird books say that + + + align:start position:0% +sometimes the bird books say that +woodpeckers can withstand the impact + + align:start position:0% +woodpeckers can withstand the impact + + + align:start position:0% +woodpeckers can withstand the impact +from pecking because they have a special + + align:start position:0% +from pecking because they have a special + + + align:start position:0% +from pecking because they have a special +material between their skulls and their + + align:start position:0% +material between their skulls and their + + + align:start position:0% +material between their skulls and their +brains. And I thought, oh well, I study + + align:start position:0% +brains. And I thought, oh well, I study + + + align:start position:0% +brains. And I thought, oh well, I study +foams and I'm interested in woodpeckers. + + align:start position:0% +foams and I'm interested in woodpeckers. + + + align:start position:0% +foams and I'm interested in woodpeckers. +I should find out what this special + + align:start position:0% +I should find out what this special + + + align:start position:0% +I should find out what this special +material is. So I started looking into + + align:start position:0% +material is. So I started looking into + + + align:start position:0% +material is. So I started looking into +this and it turns out there is no + + align:start position:0% +this and it turns out there is no + + + align:start position:0% +this and it turns out there is no +special material. People have looked at + + align:start position:0% +special material. People have looked at + + + align:start position:0% +special material. People have looked at +the anatomy of woodpecker brains and + + align:start position:0% +the anatomy of woodpecker brains and + + + align:start position:0% +the anatomy of woodpecker brains and +skulls and there is no special material. + + align:start position:0% +skulls and there is no special material. + + + align:start position:0% +skulls and there is no special material. +But it turns out there were also a group + + align:start position:0% +But it turns out there were also a group + + + align:start position:0% +But it turns out there were also a group +of neurologists in the late 1970s who + + align:start position:0% +of neurologists in the late 1970s who + + + align:start position:0% +of neurologists in the late 1970s who +got interested in why woodpeckers don't + + align:start position:0% +got interested in why woodpeckers don't + + + align:start position:0% +got interested in why woodpeckers don't +get brain injury. And they took + + align:start position:0% +get brain injury. And they took + + + align:start position:0% +get brain injury. And they took +high-speed video of a woodpecker + + align:start position:0% +high-speed video of a woodpecker + + + align:start position:0% +high-speed video of a woodpecker +pecking. And it was kind of amazing what + + align:start position:0% +pecking. And it was kind of amazing what + + + align:start position:0% +pecking. And it was kind of amazing what +they found out. So it turns out the + + align:start position:0% +they found out. So it turns out the + + + align:start position:0% +they found out. So it turns out the +woodpeckers can withstand incredibly + + align:start position:0% +woodpeckers can withstand incredibly + + + align:start position:0% +woodpeckers can withstand incredibly +high decelerations, much higher than our + + align:start position:0% +high decelerations, much higher than our + + + align:start position:0% +high decelerations, much higher than our +brains could withstand. And so I kind of + + align:start position:0% +brains could withstand. And so I kind of + + + align:start position:0% +brains could withstand. And so I kind of +got interested in this and I um decided + + align:start position:0% +got interested in this and I um decided + + + align:start position:0% +got interested in this and I um decided +to try to figure out how it works. So + + align:start position:0% +to try to figure out how it works. So + + + align:start position:0% +to try to figure out how it works. So +here's an acorn woodpecker. + + align:start position:0% +here's an acorn woodpecker. + + + align:start position:0% +here's an acorn woodpecker. +And uh let's see. I got a little video + + align:start position:0% +And uh let's see. I got a little video + + + align:start position:0% +And uh let's see. I got a little video +here so we can see little Wait a minute. + + align:start position:0% +here so we can see little Wait a minute. + + + align:start position:0% +here so we can see little Wait a minute. +Where's my There we go. + + align:start position:0% +Where's my There we go. + + + align:start position:0% +Where's my There we go. +There we go. So, here's our little acorn + + align:start position:0% +There we go. So, here's our little acorn + + + align:start position:0% +There we go. So, here's our little acorn +woodpecker. These live in California. + + align:start position:0% +woodpecker. These live in California. + + + align:start position:0% +woodpecker. These live in California. +Anybody from California? Yeah. Have you + + align:start position:0% +Anybody from California? Yeah. Have you + + + align:start position:0% +Anybody from California? Yeah. Have you +seen them? + + align:start position:0% +seen them? + + + align:start position:0% +seen them? +No. Okay. Well, you have not been + + align:start position:0% +No. Okay. Well, you have not been + + + align:start position:0% +No. Okay. Well, you have not been +looking carefully. So, here's our little + + align:start position:0% +looking carefully. So, here's our little + + + align:start position:0% +looking carefully. So, here's our little +acorn. And you can see they peck. Oh, + + align:start position:0% +acorn. And you can see they peck. Oh, + + + align:start position:0% +acorn. And you can see they peck. Oh, +like around San Francisco. + + align:start position:0% +like around San Francisco. + + + align:start position:0% +like around San Francisco. +[Laughter] + + align:start position:0% +[Laughter] + + + align:start position:0% +[Laughter] +So, so they're pecking and when they're + + align:start position:0% +So, so they're pecking and when they're + + + align:start position:0% +So, so they're pecking and when they're +pecking, you know, they don't just go + + align:start position:0% +pecking, you know, they don't just go + + + align:start position:0% +pecking, you know, they don't just go +bonk. They they do this repeatedly, + + align:start position:0% +bonk. They they do this repeatedly, + + + align:start position:0% +bonk. They they do this repeatedly, +right? They can peck at it 10 or 20 + + align:start position:0% +right? They can peck at it 10 or 20 + + + align:start position:0% +right? They can peck at it 10 or 20 +times per second. So, the question is, + + align:start position:0% +times per second. So, the question is, + + + align:start position:0% +times per second. So, the question is, +why don't they um get brain injury? + + align:start position:0% +why don't they um get brain injury? + + + align:start position:0% +why don't they um get brain injury? +So, first of all, why do they peck? So, + + align:start position:0% +So, first of all, why do they peck? So, + + + align:start position:0% +So, first of all, why do they peck? So, +as we saw in that little video, that + + align:start position:0% +as we saw in that little video, that + + + align:start position:0% +as we saw in that little video, that +woodpecker was foraging. It was trying + + align:start position:0% +woodpecker was foraging. It was trying + + + align:start position:0% +woodpecker was foraging. It was trying +to get little things out of the bark. + + align:start position:0% +to get little things out of the bark. + + + align:start position:0% +to get little things out of the bark. +And they insect or woodpeckers eat + + align:start position:0% +And they insect or woodpeckers eat + + + align:start position:0% +And they insect or woodpeckers eat +insects. Uh, and so they the bird books + + align:start position:0% +insects. Uh, and so they the bird books + + + align:start position:0% +insects. Uh, and so they the bird books +say that they can actually hear insects + + align:start position:0% +say that they can actually hear insects + + + align:start position:0% +say that they can actually hear insects +scurrying around under the bark and + + align:start position:0% +scurrying around under the bark and + + + align:start position:0% +scurrying around under the bark and +they'll peck at the bark and forage to + + align:start position:0% +they'll peck at the bark and forage to + + + align:start position:0% +they'll peck at the bark and forage to +try to get insects. And there's one + + align:start position:0% +try to get insects. And there's one + + + align:start position:0% +try to get insects. And there's one +other anatomical feature of woodpeckers + + align:start position:0% +other anatomical feature of woodpeckers + + + align:start position:0% +other anatomical feature of woodpeckers +which is kind of amazing. So, and you + + align:start position:0% +which is kind of amazing. So, and you + + + align:start position:0% +which is kind of amazing. So, and you +can see it in this picture here. So, + + align:start position:0% +can see it in this picture here. So, + + + align:start position:0% +can see it in this picture here. So, +this is the woodpecker tongue. And the + + align:start position:0% +this is the woodpecker tongue. And the + + + align:start position:0% +this is the woodpecker tongue. And the +tongue is connected to something called + + align:start position:0% +tongue is connected to something called + + + align:start position:0% +tongue is connected to something called +the hyoid process. And the hyoid process + + align:start position:0% +the hyoid process. And the hyoid process + + + align:start position:0% +the hyoid process. And the hyoid process +wraps around their eyeballs. And then + + align:start position:0% +wraps around their eyeballs. And then + + + align:start position:0% +wraps around their eyeballs. And then +when they peck, I mean, the idea is + + align:start position:0% +when they peck, I mean, the idea is + + + align:start position:0% +when they peck, I mean, the idea is +they're making a hole in the in the tree + + align:start position:0% +they're making a hole in the in the tree + + + align:start position:0% +they're making a hole in the in the tree +and they got to get their tongue into + + align:start position:0% +and they got to get their tongue into + + + align:start position:0% +and they got to get their tongue into +the hole to get the bug. And their end + + align:start position:0% +the hole to get the bug. And their end + + + align:start position:0% +the hole to get the bug. And their end +of their tongue has little barbs on it. + + align:start position:0% +of their tongue has little barbs on it. + + + align:start position:0% +of their tongue has little barbs on it. +And when they contract this thing here, + + align:start position:0% +And when they contract this thing here, + + + align:start position:0% +And when they contract this thing here, +their tongue scoots out and gets the + + align:start position:0% +their tongue scoots out and gets the + + + align:start position:0% +their tongue scoots out and gets the +little bugs. So they they peck partly to + + align:start position:0% +little bugs. So they they peck partly to + + + align:start position:0% +little bugs. So they they peck partly to +forage. They also build something called + + align:start position:0% +forage. They also build something called + + + align:start position:0% +forage. They also build something called +cavity nests. So they'll find a tree + + align:start position:0% +cavity nests. So they'll find a tree + + + align:start position:0% +cavity nests. So they'll find a tree +that's, you know, started to rot and + + align:start position:0% +that's, you know, started to rot and + + + align:start position:0% +that's, you know, started to rot and +they'll drill a sort of horizontal hole + + align:start position:0% +they'll drill a sort of horizontal hole + + + align:start position:0% +they'll drill a sort of horizontal hole +and then they'll drill a cup underneath + + align:start position:0% +and then they'll drill a cup underneath + + + align:start position:0% +and then they'll drill a cup underneath +that and they lay the eggs and have + + align:start position:0% +that and they lay the eggs and have + + + align:start position:0% +that and they lay the eggs and have +their nest at the bottom of the cup. And + + align:start position:0% +their nest at the bottom of the cup. And + + + align:start position:0% +their nest at the bottom of the cup. And +then they also, especially at this time + + align:start position:0% +then they also, especially at this time + + + align:start position:0% +then they also, especially at this time +of year, in fact, today I heard + + align:start position:0% +of year, in fact, today I heard + + + align:start position:0% +of year, in fact, today I heard +woodpeckers drumming. So it's kind of a + + align:start position:0% +woodpeckers drumming. So it's kind of a + + + align:start position:0% +woodpeckers drumming. So it's kind of a +uh, you know, one of these mating + + align:start position:0% +uh, you know, one of these mating + + + align:start position:0% +uh, you know, one of these mating +things, one of these courtship things. + + align:start position:0% +things, one of these courtship things. + + + align:start position:0% +things, one of these courtship things. +So woodpeckers will peck on a hollow + + align:start position:0% +So woodpeckers will peck on a hollow + + + align:start position:0% +So woodpeckers will peck on a hollow +branch or a hollow tree just to make a + + align:start position:0% +branch or a hollow tree just to make a + + + align:start position:0% +branch or a hollow tree just to make a +big loud noise to say, "Here I am + + align:start position:0% +big loud noise to say, "Here I am + + + align:start position:0% +big loud noise to say, "Here I am +looking for sex. I'm ready. You know, + + align:start position:0% +looking for sex. I'm ready. You know, + + + align:start position:0% +looking for sex. I'm ready. You know, +this is my territory. Uh, and so in the + + align:start position:0% +this is my territory. Uh, and so in the + + + align:start position:0% +this is my territory. Uh, and so in the +spring, so this time of year, you hear + + align:start position:0% +spring, so this time of year, you hear + + + align:start position:0% +spring, so this time of year, you hear +woodpeckers drumming. And I think + + align:start position:0% +woodpeckers drumming. And I think + + + align:start position:0% +woodpeckers drumming. And I think +naturally they do this on hollow trees + + align:start position:0% +naturally they do this on hollow trees + + + align:start position:0% +naturally they do this on hollow trees +to try to make a big sound, but they + + align:start position:0% +to try to make a big sound, but they + + + align:start position:0% +to try to make a big sound, but they +have adapted to um metal downspouts, + + align:start position:0% +have adapted to um metal downspouts, + + + align:start position:0% +have adapted to um metal downspouts, +which are also very effective for making + + align:start position:0% +which are also very effective for making + + + align:start position:0% +which are also very effective for making +this loud noise. And people who've I + + align:start position:0% +this loud noise. And people who've I + + + align:start position:0% +this loud noise. And people who've I +wrote a paper on this. People who've + + align:start position:0% +wrote a paper on this. People who've + + + align:start position:0% +wrote a paper on this. People who've +read my paper sometimes email me and + + align:start position:0% +read my paper sometimes email me and + + + align:start position:0% +read my paper sometimes email me and +say, "Oh, I heard you know about + + align:start position:0% +say, "Oh, I heard you know about + + + align:start position:0% +say, "Oh, I heard you know about +woodpecker pecking. How can I get them + + align:start position:0% +woodpecker pecking. How can I get them + + + align:start position:0% +woodpecker pecking. How can I get them +to stop drumming on my downspout?" + + align:start position:0% +to stop drumming on my downspout?" + + + align:start position:0% +to stop drumming on my downspout?" +Because it's kind of annoying if you're + + align:start position:0% +Because it's kind of annoying if you're + + + align:start position:0% +Because it's kind of annoying if you're +the human inside the house. So anyway, + + align:start position:0% +the human inside the house. So anyway, + + + align:start position:0% +the human inside the house. So anyway, +they they peck for these reasons. And + + align:start position:0% +they they peck for these reasons. And + + + align:start position:0% +they they peck for these reasons. And +then acorn woodpeckers are special. + + align:start position:0% +then acorn woodpeckers are special. + + + align:start position:0% +then acorn woodpeckers are special. +Acorn woodpeckers are what I think of as + + align:start position:0% +Acorn woodpeckers are what I think of as + + + align:start position:0% +Acorn woodpeckers are what I think of as +the champions of pecking. And they do + + align:start position:0% +the champions of pecking. And they do + + + align:start position:0% +the champions of pecking. And they do +one more behavior. So here's from David + + align:start position:0% +one more behavior. So here's from David + + + align:start position:0% +one more behavior. So here's from David +Sibli's beautiful uh guide to birds. + + align:start position:0% +Sibli's beautiful uh guide to birds. + + + align:start position:0% +Sibli's beautiful uh guide to birds. +Here's the acorn woodpecker. They store + + align:start position:0% +Here's the acorn woodpecker. They store + + + align:start position:0% +Here's the acorn woodpecker. They store +acorns in what's called a granary. And + + align:start position:0% +acorns in what's called a granary. And + + + align:start position:0% +acorns in what's called a granary. And +they get they look at old uh kind of old + + align:start position:0% +they get they look at old uh kind of old + + + align:start position:0% +they get they look at old uh kind of old +tree trunks that are beginning to rot + + align:start position:0% +tree trunks that are beginning to rot + + + align:start position:0% +tree trunks that are beginning to rot +and they peck holes in the tree trunk + + align:start position:0% +and they peck holes in the tree trunk + + + align:start position:0% +and they peck holes in the tree trunk +and they store the acorns in the holes. + + align:start position:0% +and they store the acorns in the holes. + + + align:start position:0% +and they store the acorns in the holes. +So see all those little like dark dots + + align:start position:0% +So see all those little like dark dots + + + align:start position:0% +So see all those little like dark dots +on that trunk? Those are all holes that + + align:start position:0% +on that trunk? Those are all holes that + + + align:start position:0% +on that trunk? Those are all holes that +the acorn woodpecker has pecked. And + + align:start position:0% +the acorn woodpecker has pecked. And + + + align:start position:0% +the acorn woodpecker has pecked. And +they'll do this in they live in social + + align:start position:0% +they'll do this in they live in social + + + align:start position:0% +they'll do this in they live in social +groups. So there might be like 10 or 20 + + align:start position:0% +groups. So there might be like 10 or 20 + + + align:start position:0% +groups. So there might be like 10 or 20 +of them living together. + + align:start position:0% +of them living together. + + + align:start position:0% +of them living together. +And they'll peck like 10,000 holes into + + align:start position:0% +And they'll peck like 10,000 holes into + + + align:start position:0% +And they'll peck like 10,000 holes into +their granary. There'll be thousands and + + align:start position:0% +their granary. There'll be thousands and + + + align:start position:0% +their granary. There'll be thousands and +thousands of these holes. And here we + + align:start position:0% +thousands of these holes. And here we + + + align:start position:0% +thousands of these holes. And here we +have the acorn woodpecker with the acorn + + align:start position:0% +have the acorn woodpecker with the acorn + + + align:start position:0% +have the acorn woodpecker with the acorn +in its beak. And you can see there's + + align:start position:0% +in its beak. And you can see there's + + + align:start position:0% +in its beak. And you can see there's +some of these holes have acorns and some + + align:start position:0% +some of these holes have acorns and some + + + align:start position:0% +some of these holes have acorns and some +of them are empty. So here's the acorn + + align:start position:0% +of them are empty. So here's the acorn + + + align:start position:0% +of them are empty. So here's the acorn +woodpecker in action. And here's the + + align:start position:0% +woodpecker in action. And here's the + + + align:start position:0% +woodpecker in action. And here's the +little video again. I won't play the + + align:start position:0% +little video again. I won't play the + + + align:start position:0% +little video again. I won't play the +video. So I I often give this talk for + + align:start position:0% +video. So I I often give this talk for + + + align:start position:0% +video. So I I often give this talk for +non-engineers. So I'm going to explain + + align:start position:0% +non-engineers. So I'm going to explain + + + align:start position:0% +non-engineers. So I'm going to explain +some things that you know there's going + + align:start position:0% +some things that you know there's going + + + align:start position:0% +some things that you know there's going +to be some writing on the slides that + + align:start position:0% +to be some writing on the slides that + + + align:start position:0% +to be some writing on the slides that +you guys already know. So the impact + + align:start position:0% +you guys already know. So the impact + + + align:start position:0% +you guys already know. So the impact +force depends on the deceleration, how + + align:start position:0% +force depends on the deceleration, how + + + align:start position:0% +force depends on the deceleration, how +quickly the brain stops when the beak + + align:start position:0% +quickly the brain stops when the beak + + + align:start position:0% +quickly the brain stops when the beak +hits the tree. And I should mention + + align:start position:0% +hits the tree. And I should mention + + + align:start position:0% +hits the tree. And I should mention +these videos are from the Cornell Lab of + + align:start position:0% +these videos are from the Cornell Lab of + + + align:start position:0% +these videos are from the Cornell Lab of +Ornithology. They have an amazing + + align:start position:0% +Ornithology. They have an amazing + + + align:start position:0% +Ornithology. They have an amazing +collection of bird audio, like bird + + align:start position:0% +collection of bird audio, like bird + + + align:start position:0% +collection of bird audio, like bird +calls, bird songs, and bird photographs + + align:start position:0% +calls, bird songs, and bird photographs + + + align:start position:0% +calls, bird songs, and bird photographs +and videos. It's it's incredible the + + align:start position:0% +and videos. It's it's incredible the + + + align:start position:0% +and videos. It's it's incredible the +collection that they've got. Um, and + + align:start position:0% +collection that they've got. Um, and + + + align:start position:0% +collection that they've got. Um, and +then I explain what acceleration is. So, + + align:start position:0% +then I explain what acceleration is. So, + + + align:start position:0% +then I explain what acceleration is. So, +I'm going to put acceleration in terms + + align:start position:0% +I'm going to put acceleration in terms + + + align:start position:0% +I'm going to put acceleration in terms +of gravity. And when the when the beak + + align:start position:0% +of gravity. And when the when the beak + + + align:start position:0% +of gravity. And when the when the beak +hits the tree, there's going to be a + + align:start position:0% +hits the tree, there's going to be a + + + align:start position:0% +hits the tree, there's going to be a +deceleration on impact. And just as a + + align:start position:0% +deceleration on impact. And just as a + + + align:start position:0% +deceleration on impact. And just as a +comparison, human brain injury occurs + + align:start position:0% +comparison, human brain injury occurs + + + align:start position:0% +comparison, human brain injury occurs +roughly at about 100g. Uh, and so the + + align:start position:0% +roughly at about 100g. Uh, and so the + + + align:start position:0% +roughly at about 100g. Uh, and so the +question is, how much deceleration can + + align:start position:0% +question is, how much deceleration can + + + align:start position:0% +question is, how much deceleration can +the woodpecker brain take? And that's + + align:start position:0% +the woodpecker brain take? And that's + + + align:start position:0% +the woodpecker brain take? And that's +where the neurologists in the Bay Area + + align:start position:0% +where the neurologists in the Bay Area + + + align:start position:0% +where the neurologists in the Bay Area +come into the picture. They uh found out + + align:start position:0% +come into the picture. They uh found out + + + align:start position:0% +come into the picture. They uh found out +that there was a park ranger I think um + + align:start position:0% +that there was a park ranger I think um + + + align:start position:0% +that there was a park ranger I think um +maybe at Point Race just north of San + + align:start position:0% +maybe at Point Race just north of San + + + align:start position:0% +maybe at Point Race just north of San +Francisco and he had an acorn woodpecker + + align:start position:0% +Francisco and he had an acorn woodpecker + + + align:start position:0% +Francisco and he had an acorn woodpecker +that I don't know had an injured wing or + + align:start position:0% +that I don't know had an injured wing or + + + align:start position:0% +that I don't know had an injured wing or +something. Anyway, he had this acorn + + align:start position:0% +something. Anyway, he had this acorn + + + align:start position:0% +something. Anyway, he had this acorn +woodpecker that he kept um and they were + + align:start position:0% +woodpecker that he kept um and they were + + + align:start position:0% +woodpecker that he kept um and they were +able to use this acorn woodpecker and + + align:start position:0% +able to use this acorn woodpecker and + + + align:start position:0% +able to use this acorn woodpecker and +they took high-speed video of the pe + + align:start position:0% +they took high-speed video of the pe + + + align:start position:0% +they took high-speed video of the pe +woodpecker pecking. So from the + + align:start position:0% +woodpecker pecking. So from the + + + align:start position:0% +woodpecker pecking. So from the +high-speed video, the video that they + + align:start position:0% +high-speed video, the video that they + + + align:start position:0% +high-speed video, the video that they +took went at something like uh 2,000 + + align:start position:0% +took went at something like uh 2,000 + + + align:start position:0% +took went at something like uh 2,000 +frames a second. So they have a picture + + align:start position:0% +frames a second. So they have a picture + + + align:start position:0% +frames a second. So they have a picture +of where the head is every 2,000th of a + + align:start position:0% +of where the head is every 2,000th of a + + + align:start position:0% +of where the head is every 2,000th of a +second. So if you know the position at + + align:start position:0% +second. So if you know the position at + + + align:start position:0% +second. So if you know the position at +these times, you can get the velocity + + align:start position:0% +these times, you can get the velocity + + + align:start position:0% +these times, you can get the velocity +and you can get the deceleration, right? + + align:start position:0% +and you can get the deceleration, right? + + + align:start position:0% +and you can get the deceleration, right? +So they measured the deceleration and + + align:start position:0% +So they measured the deceleration and + + + align:start position:0% +So they measured the deceleration and +they measured some amazing things. So + + align:start position:0% +they measured some amazing things. So + + + align:start position:0% +they measured some amazing things. So +they measured that on impact the + + align:start position:0% +they measured that on impact the + + + align:start position:0% +they measured that on impact the +woodpecker's bill was going something + + align:start position:0% +woodpecker's bill was going something + + + align:start position:0% +woodpecker's bill was going something +like 15 miles an hour and the + + align:start position:0% +like 15 miles an hour and the + + + align:start position:0% +like 15 miles an hour and the +decelerations were up to 1500g. So many + + align:start position:0% +decelerations were up to 1500g. So many + + + align:start position:0% +decelerations were up to 1500g. So many +times more than what we can withstand. + + align:start position:0% +times more than what we can withstand. + + + align:start position:0% +times more than what we can withstand. +And they also measured the stopping time + + align:start position:0% +And they also measured the stopping time + + + align:start position:0% +And they also measured the stopping time +and they they thought it was between + + align:start position:0% +and they they thought it was between + + + align:start position:0% +and they they thought it was between +about 1/500th to 1/ 1,000th of a second. + + align:start position:0% +about 1/500th to 1/ 1,000th of a second. + + + align:start position:0% +about 1/500th to 1/ 1,000th of a second. +And that's going to be important later + + align:start position:0% +And that's going to be important later + + + align:start position:0% +And that's going to be important later +on. So one of the interesting things + + align:start position:0% +on. So one of the interesting things + + + align:start position:0% +on. So one of the interesting things +about this was how they got this whole + + align:start position:0% +about this was how they got this whole + + + align:start position:0% +about this was how they got this whole +thing set up. So I don't know how many + + align:start position:0% +thing set up. So I don't know how many + + + align:start position:0% +thing set up. So I don't know how many +of you do eur ops, but you know part of + + align:start position:0% +of you do eur ops, but you know part of + + + align:start position:0% +of you do eur ops, but you know part of +the thing in doing europs and doing + + align:start position:0% +the thing in doing europs and doing + + + align:start position:0% +the thing in doing europs and doing +experiments in labs, just how do you do + + align:start position:0% +experiments in labs, just how do you do + + + align:start position:0% +experiments in labs, just how do you do +the experiment? So you know the park + + align:start position:0% +the experiment? So you know the park + + + align:start position:0% +the experiment? So you know the park +rangers got the acorn woodpecker. That's + + align:start position:0% +rangers got the acorn woodpecker. That's + + + align:start position:0% +rangers got the acorn woodpecker. That's +all very good, but they have to get the + + align:start position:0% +all very good, but they have to get the + + + align:start position:0% +all very good, but they have to get the +woodpecker to peck in front of the + + align:start position:0% +woodpecker to peck in front of the + + + align:start position:0% +woodpecker to peck in front of the +camera, right? They have to get the + + align:start position:0% +camera, right? They have to get the + + + align:start position:0% +camera, right? They have to get the +camera to turn on as it's pecking and + + align:start position:0% +camera to turn on as it's pecking and + + + align:start position:0% +camera to turn on as it's pecking and +all this. there's some experimental + + align:start position:0% +all this. there's some experimental + + + align:start position:0% +all this. there's some experimental +challenges. So the important thing, the + + align:start position:0% +challenges. So the important thing, the + + + align:start position:0% +challenges. So the important thing, the +critical thing is the date of the paper. + + align:start position:0% +critical thing is the date of the paper. + + + align:start position:0% +critical thing is the date of the paper. +This was written in 1979, which meant + + align:start position:0% +This was written in 1979, which meant + + + align:start position:0% +This was written in 1979, which meant +they probably did the experiments in + + align:start position:0% +they probably did the experiments in + + + align:start position:0% +they probably did the experiments in +1978 and I was a graduate student in + + align:start position:0% +1978 and I was a graduate student in + + + align:start position:0% +1978 and I was a graduate student in +1978. And I can report there were no + + align:start position:0% +1978. And I can report there were no + + + align:start position:0% +1978. And I can report there were no +Apple computers in 1978. There were no + + align:start position:0% +Apple computers in 1978. There were no + + + align:start position:0% +Apple computers in 1978. There were no +laptops. You couldn't just kind of do + + align:start position:0% +laptops. You couldn't just kind of do + + + align:start position:0% +laptops. You couldn't just kind of do +your little PowerPoint slides. And most + + align:start position:0% +your little PowerPoint slides. And most + + + align:start position:0% +your little PowerPoint slides. And most +offices had something called an IBM + + align:start position:0% +offices had something called an IBM + + + align:start position:0% +offices had something called an IBM +select electric typewriter. I don't know + + align:start position:0% +select electric typewriter. I don't know + + + align:start position:0% +select electric typewriter. I don't know +if you've ever seen the old IBM + + align:start position:0% +if you've ever seen the old IBM + + + align:start position:0% +if you've ever seen the old IBM +typewriters, but the typewriters when + + align:start position:0% +typewriters, but the typewriters when + + + align:start position:0% +typewriters, but the typewriters when +you typed on the typewriters, they made + + align:start position:0% +you typed on the typewriters, they made + + + align:start position:0% +you typed on the typewriters, they made +these noises and it sounded kind of like + + align:start position:0% +these noises and it sounded kind of like + + + align:start position:0% +these noises and it sounded kind of like +a woodpecker pecking. And the ranger had + + align:start position:0% +a woodpecker pecking. And the ranger had + + + align:start position:0% +a woodpecker pecking. And the ranger had +one of these typewriters in his office. + + align:start position:0% +one of these typewriters in his office. + + + align:start position:0% +one of these typewriters in his office. +And he had discovered that if he typed + + align:start position:0% +And he had discovered that if he typed + + + align:start position:0% +And he had discovered that if he typed +on the typewriter, the woodpecker + + align:start position:0% +on the typewriter, the woodpecker + + + align:start position:0% +on the typewriter, the woodpecker +thought, "Oh, there's another + + align:start position:0% +thought, "Oh, there's another + + + align:start position:0% +thought, "Oh, there's another +woodpecker. I'll start pecking." And so + + align:start position:0% +woodpecker. I'll start pecking." And so + + + align:start position:0% +woodpecker. I'll start pecking." And so +they used the typewriter as a way to get + + align:start position:0% +they used the typewriter as a way to get + + + align:start position:0% +they used the typewriter as a way to get +the woodpeckers to peck. And I think + + align:start position:0% +the woodpeckers to peck. And I think + + + align:start position:0% +the woodpeckers to peck. And I think +they had some old stump and they put I + + align:start position:0% +they had some old stump and they put I + + + align:start position:0% +they had some old stump and they put I +don't know if they put nuts or peanut + + align:start position:0% +don't know if they put nuts or peanut + + + align:start position:0% +don't know if they put nuts or peanut +butter or something into the stump to + + align:start position:0% +butter or something into the stump to + + + align:start position:0% +butter or something into the stump to +get the woodpecker to peck at it because + + align:start position:0% +get the woodpecker to peck at it because + + + align:start position:0% +get the woodpecker to peck at it because +they needed to peck at a particular + + align:start position:0% +they needed to peck at a particular + + + align:start position:0% +they needed to peck at a particular +spot. So they have the camera all set + + align:start position:0% +spot. So they have the camera all set + + + align:start position:0% +spot. So they have the camera all set +up. So anyway, they had this whole kind + + align:start position:0% +up. So anyway, they had this whole kind + + + align:start position:0% +up. So anyway, they had this whole kind +of arrangement to um to do this + + align:start position:0% +of arrangement to um to do this + + + align:start position:0% +of arrangement to um to do this +high-speed video of the woodpecker + + align:start position:0% +high-speed video of the woodpecker + + + align:start position:0% +high-speed video of the woodpecker +pecking. Okay, so it goes at up to + + align:start position:0% +pecking. Okay, so it goes at up to + + + align:start position:0% +pecking. Okay, so it goes at up to +1500g, which is kind of amazing. And + + align:start position:0% +1500g, which is kind of amazing. And + + + align:start position:0% +1500g, which is kind of amazing. And +then, you know, remember also they do + + align:start position:0% +then, you know, remember also they do + + + align:start position:0% +then, you know, remember also they do +this repeatedly. They do it at like 10 + + align:start position:0% +this repeatedly. They do it at like 10 + + + align:start position:0% +this repeatedly. They do it at like 10 +or 20 times a second. Um then this is + + align:start position:0% +or 20 times a second. Um then this is + + + align:start position:0% +or 20 times a second. Um then this is +just explaining what stress is, but you + + align:start position:0% +just explaining what stress is, but you + + + align:start position:0% +just explaining what stress is, but you +already know what stress is, so I'm + + align:start position:0% +already know what stress is, so I'm + + + align:start position:0% +already know what stress is, so I'm +going to skip over that. And so the way + + align:start position:0% +going to skip over that. And so the way + + + align:start position:0% +going to skip over that. And so the way +you can think about this is to think + + align:start position:0% +you can think about this is to think + + + align:start position:0% +you can think about this is to think +about it in terms of a scaling argument. + + align:start position:0% +about it in terms of a scaling argument. + + + align:start position:0% +about it in terms of a scaling argument. +So imagine there's the brain and there's + + align:start position:0% +So imagine there's the brain and there's + + + align:start position:0% +So imagine there's the brain and there's +the skull. And when the head hits the + + align:start position:0% +the skull. And when the head hits the + + + align:start position:0% +the skull. And when the head hits the +tree, the brain's going to accelerate + + align:start position:0% +tree, the brain's going to accelerate + + + align:start position:0% +tree, the brain's going to accelerate +and the skull or the brain and the skull + + align:start position:0% +and the skull or the brain and the skull + + + align:start position:0% +and the skull or the brain and the skull +are both going to decelerate. And you + + align:start position:0% +are both going to decelerate. And you + + + align:start position:0% +are both going to decelerate. And you +can think of the stress as the force + + align:start position:0% +can think of the stress as the force + + + align:start position:0% +can think of the stress as the force +over the area. So the force is the mass + + align:start position:0% +over the area. So the force is the mass + + + align:start position:0% +over the area. So the force is the mass +times the deceleration over the area. So + + align:start position:0% +times the deceleration over the area. So + + + align:start position:0% +times the deceleration over the area. So +that value for the woodpecker you can + + align:start position:0% +that value for the woodpecker you can + + + align:start position:0% +that value for the woodpecker you can +say is roughly equal to the same values + + align:start position:0% +say is roughly equal to the same values + + + align:start position:0% +say is roughly equal to the same values +but for the human. So what that sort of + + align:start position:0% +but for the human. So what that sort of + + + align:start position:0% +but for the human. So what that sort of +argument relies on is the idea that the + + align:start position:0% +argument relies on is the idea that the + + + align:start position:0% +argument relies on is the idea that the +stress to cause damage in the woodpecker + + align:start position:0% +stress to cause damage in the woodpecker + + + align:start position:0% +stress to cause damage in the woodpecker +brain is similar to to the stress to + + align:start position:0% +brain is similar to to the stress to + + + align:start position:0% +brain is similar to to the stress to +cause damage in the human brain. And + + align:start position:0% +cause damage in the human brain. And + + + align:start position:0% +cause damage in the human brain. And +that's not totally unre unreasonable. So + + align:start position:0% +that's not totally unre unreasonable. So + + + align:start position:0% +that's not totally unre unreasonable. So +if you if you look at bone for example + + align:start position:0% +if you if you look at bone for example + + + align:start position:0% +if you if you look at bone for example +like when you measure the strength of + + align:start position:0% +like when you measure the strength of + + + align:start position:0% +like when you measure the strength of +the whale bones it's not going to be + + align:start position:0% +the whale bones it's not going to be + + + align:start position:0% +the whale bones it's not going to be +that different from what you would + + align:start position:0% +that different from what you would + + + align:start position:0% +that different from what you would +measure from human bones. So when you + + align:start position:0% +measure from human bones. So when you + + + align:start position:0% +measure from human bones. So when you +look at a particular type of tissue and + + align:start position:0% +look at a particular type of tissue and + + + align:start position:0% +look at a particular type of tissue and +you look at the strength of it in + + align:start position:0% +you look at the strength of it in + + + align:start position:0% +you look at the strength of it in +different species, the properties aren't + + align:start position:0% +different species, the properties aren't + + + align:start position:0% +different species, the properties aren't +that different from one species to + + align:start position:0% +that different from one species to + + + align:start position:0% +that different from one species to +another. So let's say the brain tissue + + align:start position:0% +another. So let's say the brain tissue + + + align:start position:0% +another. So let's say the brain tissue +has gets damaged at the same stress in + + align:start position:0% +has gets damaged at the same stress in + + + align:start position:0% +has gets damaged at the same stress in +the two species. So we can write this + + align:start position:0% +the two species. So we can write this + + + align:start position:0% +the two species. So we can write this +sort of equation down. Uh and then the + + align:start position:0% +sort of equation down. Uh and then the + + + align:start position:0% +sort of equation down. Uh and then the +mass oops see there we go. The mass is + + align:start position:0% +mass oops see there we go. The mass is + + + align:start position:0% +mass oops see there we go. The mass is +going to depend on the density of the + + align:start position:0% +going to depend on the density of the + + + align:start position:0% +going to depend on the density of the +brain tissue times the volume. And the + + align:start position:0% +brain tissue times the volume. And the + + + align:start position:0% +brain tissue times the volume. And the +volume goes as the radius cubed. And the + + align:start position:0% +volume goes as the radius cubed. And the + + + align:start position:0% +volume goes as the radius cubed. And the +density is going to be the same for the + + align:start position:0% +density is going to be the same for the + + + align:start position:0% +density is going to be the same for the +woodpecker or for the human. So assume + + align:start position:0% +woodpecker or for the human. So assume + + + align:start position:0% +woodpecker or for the human. So assume +the brain tissue has the same kind of + + align:start position:0% +the brain tissue has the same kind of + + + align:start position:0% +the brain tissue has the same kind of +basic stuff. So the mass goes as the + + align:start position:0% +basic stuff. So the mass goes as the + + + align:start position:0% +basic stuff. So the mass goes as the +radius cubed and the area of contact is + + align:start position:0% +radius cubed and the area of contact is + + + align:start position:0% +radius cubed and the area of contact is +going to go as the radius squared. And + + align:start position:0% +going to go as the radius squared. And + + + align:start position:0% +going to go as the radius squared. And +so there's a a radius term. So you can + + align:start position:0% +so there's a a radius term. So you can + + + align:start position:0% +so there's a a radius term. So you can +say the radius times the deceleration in + + align:start position:0% +say the radius times the deceleration in + + + align:start position:0% +say the radius times the deceleration in +the woodpecker should be equal to the + + align:start position:0% +the woodpecker should be equal to the + + + align:start position:0% +the woodpecker should be equal to the +radius times the deceleration in the + + align:start position:0% +radius times the deceleration in the + + + align:start position:0% +radius times the deceleration in the +human. And obviously the woodpecker + + align:start position:0% +human. And obviously the woodpecker + + + align:start position:0% +human. And obviously the woodpecker +radius is going to be a lot smaller. So + + align:start position:0% +radius is going to be a lot smaller. So + + + align:start position:0% +radius is going to be a lot smaller. So +that woodpecker deceleration is going to + + align:start position:0% +that woodpecker deceleration is going to + + + align:start position:0% +that woodpecker deceleration is going to +be a lot bigger. So part of the thing is + + align:start position:0% +be a lot bigger. So part of the thing is + + + align:start position:0% +be a lot bigger. So part of the thing is +the brain is just a lot smaller. Then + + align:start position:0% +the brain is just a lot smaller. Then + + + align:start position:0% +the brain is just a lot smaller. Then +there's there's another factor that + + align:start position:0% +there's there's another factor that + + + align:start position:0% +there's there's another factor that +comes into it. These are um photographs + + align:start position:0% +comes into it. These are um photographs + + + align:start position:0% +comes into it. These are um photographs +of of a acorn woodpecker skull and a + + align:start position:0% +of of a acorn woodpecker skull and a + + + align:start position:0% +of of a acorn woodpecker skull and a +human skull that I got from the Museum + + align:start position:0% +human skull that I got from the Museum + + + align:start position:0% +human skull that I got from the Museum +of Comparative Zoolology at Harvard. So + + align:start position:0% +of Comparative Zoolology at Harvard. So + + + align:start position:0% +of Comparative Zoolology at Harvard. So +this is looking down on the top and this + + align:start position:0% +this is looking down on the top and this + + + align:start position:0% +this is looking down on the top and this +is sort of an elevation view. And if you + + align:start position:0% +is sort of an elevation view. And if you + + + align:start position:0% +is sort of an elevation view. And if you +think of the brain as roughly a + + align:start position:0% +think of the brain as roughly a + + + align:start position:0% +think of the brain as roughly a +hemisphere, I mean obviously it's not a + + align:start position:0% +hemisphere, I mean obviously it's not a + + + align:start position:0% +hemisphere, I mean obviously it's not a +perfect hemisphere but let's say it's + + align:start position:0% +perfect hemisphere but let's say it's + + + align:start position:0% +perfect hemisphere but let's say it's +roughly a hemisphere. The orientation of + + align:start position:0% +roughly a hemisphere. The orientation of + + + align:start position:0% +roughly a hemisphere. The orientation of +the brain in the skull is slightly + + align:start position:0% +the brain in the skull is slightly + + + align:start position:0% +the brain in the skull is slightly +different in the birds and in the human. + + align:start position:0% +different in the birds and in the human. + + + align:start position:0% +different in the birds and in the human. +So if you think of it as being this way + + align:start position:0% +So if you think of it as being this way + + + align:start position:0% +So if you think of it as being this way +on in the woodpecker, it's turned + + align:start position:0% +on in the woodpecker, it's turned + + + align:start position:0% +on in the woodpecker, it's turned +roughly this way on and the contact + + align:start position:0% +roughly this way on and the contact + + + align:start position:0% +roughly this way on and the contact +area, think of this as the contact area, + + align:start position:0% +area, think of this as the contact area, + + + align:start position:0% +area, think of this as the contact area, +sort of projected area would be a full + + align:start position:0% +sort of projected area would be a full + + + align:start position:0% +sort of projected area would be a full +circle. And in the human, the brain is + + align:start position:0% +circle. And in the human, the brain is + + + align:start position:0% +circle. And in the human, the brain is +more this way on. And then the sort of + + align:start position:0% +more this way on. And then the sort of + + + align:start position:0% +more this way on. And then the sort of +projected contact area is a semicircle. + + align:start position:0% +projected contact area is a semicircle. + + + align:start position:0% +projected contact area is a semicircle. +So there's a factor of two difference + + align:start position:0% +So there's a factor of two difference + + + align:start position:0% +So there's a factor of two difference +just because of the orientation of the + + align:start position:0% +just because of the orientation of the + + + align:start position:0% +just because of the orientation of the +brain. And so I've I put the factor of + + align:start position:0% +brain. And so I've I put the factor of + + + align:start position:0% +brain. And so I've I put the factor of +two that accounts for that. So then I + + align:start position:0% +two that accounts for that. So then I + + + align:start position:0% +two that accounts for that. So then I +could say the deceleration that the + + align:start position:0% +could say the deceleration that the + + + align:start position:0% +could say the deceleration that the +woodpecker can take is twice the ratio + + align:start position:0% +woodpecker can take is twice the ratio + + + align:start position:0% +woodpecker can take is twice the ratio +of the radi of the human and the + + align:start position:0% +of the radi of the human and the + + + align:start position:0% +of the radi of the human and the +woodpecker brain times the deceleration + + align:start position:0% +woodpecker brain times the deceleration + + + align:start position:0% +woodpecker brain times the deceleration +the human can take. And this was around + + align:start position:0% +the human can take. And this was around + + + align:start position:0% +the human can take. And this was around +100g, remember? So then I wanted to know + + align:start position:0% +100g, remember? So then I wanted to know + + + align:start position:0% +100g, remember? So then I wanted to know +what the ratio of the sizes was. And I + + align:start position:0% +what the ratio of the sizes was. And I + + + align:start position:0% +what the ratio of the sizes was. And I +thought, "Oh geez, I'm going to have to, + + align:start position:0% +thought, "Oh geez, I'm going to have to, + + + align:start position:0% +thought, "Oh geez, I'm going to have to, +you know, mess around with skulls and + + align:start position:0% +you know, mess around with skulls and + + + align:start position:0% +you know, mess around with skulls and +try to make some sort of measurements + + align:start position:0% +try to make some sort of measurements + + + align:start position:0% +try to make some sort of measurements +and this is going to be a drag." And + + align:start position:0% +and this is going to be a drag." And + + + align:start position:0% +and this is going to be a drag." And +then I found this paper. I couldn't + + align:start position:0% +then I found this paper. I couldn't + + + align:start position:0% +then I found this paper. I couldn't +believe it. I found this paper called + + align:start position:0% +believe it. I found this paper called + + + align:start position:0% +believe it. I found this paper called +brain size in birds. And this guy had + + align:start position:0% +brain size in birds. And this guy had + + + align:start position:0% +brain size in birds. And this guy had +table after table after table of the + + align:start position:0% +table after table after table of the + + + align:start position:0% +table after table after table of the +mass of the brain in different birds. + + align:start position:0% +mass of the brain in different birds. + + + align:start position:0% +mass of the brain in different birds. +And he had the acorn woodpecker, lucky + + align:start position:0% +And he had the acorn woodpecker, lucky + + + align:start position:0% +And he had the acorn woodpecker, lucky +for me. So if you just assume that the + + align:start position:0% +for me. So if you just assume that the + + + align:start position:0% +for me. So if you just assume that the +the brain is roughly a hemisphere, if + + align:start position:0% +the brain is roughly a hemisphere, if + + + align:start position:0% +the brain is roughly a hemisphere, if +you have the mass, you can work out + + align:start position:0% +you have the mass, you can work out + + + align:start position:0% +you have the mass, you can work out +roughly what the radius is. So it turns + + align:start position:0% +roughly what the radius is. So it turns + + + align:start position:0% +roughly what the radius is. So it turns +out there's a factor of eight difference + + align:start position:0% +out there's a factor of eight difference + + + align:start position:0% +out there's a factor of eight difference +between the radi. And so uh the human + + align:start position:0% +between the radi. And so uh the human + + + align:start position:0% +between the radi. And so uh the human +brain's about eight times the size of + + align:start position:0% +brain's about eight times the size of + + + align:start position:0% +brain's about eight times the size of +the woodpecker. And then if you take + + align:start position:0% +the woodpecker. And then if you take + + + align:start position:0% +the woodpecker. And then if you take +into account this factor of two, that + + align:start position:0% +into account this factor of two, that + + + align:start position:0% +into account this factor of two, that +means the woodpecker should be able to + + align:start position:0% +means the woodpecker should be able to + + + align:start position:0% +means the woodpecker should be able to +tolerate a deceleration of 16 times what + + align:start position:0% +tolerate a deceleration of 16 times what + + + align:start position:0% +tolerate a deceleration of 16 times what +the human can. So remember I said the + + align:start position:0% +the human can. So remember I said the + + + align:start position:0% +the human can. So remember I said the +human can take about 100. So this would + + align:start position:0% +human can take about 100. So this would + + + align:start position:0% +human can take about 100. So this would +get the woodpecker up to 1600, but they + + align:start position:0% +get the woodpecker up to 1600, but they + + + align:start position:0% +get the woodpecker up to 1600, but they +measured 1500. And I'm a civil engineer. + + align:start position:0% +measured 1500. And I'm a civil engineer. + + + align:start position:0% +measured 1500. And I'm a civil engineer. +Originally, I like big factors of + + align:start position:0% +Originally, I like big factors of + + + align:start position:0% +Originally, I like big factors of +safety. That's a little too close for + + align:start position:0% +safety. That's a little too close for + + + align:start position:0% +safety. That's a little too close for +comfort for me. Uh and so it turns out + + align:start position:0% +comfort for me. Uh and so it turns out + + + align:start position:0% +comfort for me. Uh and so it turns out +there's one more factor that that + + align:start position:0% +there's one more factor that that + + + align:start position:0% +there's one more factor that that +matters. Uh people have studied human + + align:start position:0% +matters. Uh people have studied human + + + align:start position:0% +matters. Uh people have studied human +brain injury pretty extensively. And one + + align:start position:0% +brain injury pretty extensively. And one + + + align:start position:0% +brain injury pretty extensively. And one +of the things they've looked at is how + + align:start position:0% +of the things they've looked at is how + + + align:start position:0% +of the things they've looked at is how +much acceleration you can tolerate + + align:start position:0% +much acceleration you can tolerate + + + align:start position:0% +much acceleration you can tolerate +without injury uh relative to the + + align:start position:0% +without injury uh relative to the + + + align:start position:0% +without injury uh relative to the +duration of the impact. So this is from + + align:start position:0% +duration of the impact. So this is from + + + align:start position:0% +duration of the impact. So this is from +a car crash conference. Uh so here's the + + align:start position:0% +a car crash conference. Uh so here's the + + + align:start position:0% +a car crash conference. Uh so here's the +tolerable acceleration and here's the + + align:start position:0% +tolerable acceleration and here's the + + + align:start position:0% +tolerable acceleration and here's the +duration of the impact. And typically + + align:start position:0% +duration of the impact. And typically + + + align:start position:0% +duration of the impact. And typically +for human head impacts the deceleration + + align:start position:0% +for human head impacts the deceleration + + + align:start position:0% +for human head impacts the deceleration +occurs over a few milliseconds like over + + align:start position:0% +occurs over a few milliseconds like over + + + align:start position:0% +occurs over a few milliseconds like over +3 to 10 milliseconds. So if this is the + + align:start position:0% +3 to 10 milliseconds. So if this is the + + + align:start position:0% +3 to 10 milliseconds. So if this is the +duration of the typical head impact for + + align:start position:0% +duration of the typical head impact for + + + align:start position:0% +duration of the typical head impact for +a human, here's the range of the + + align:start position:0% +a human, here's the range of the + + + align:start position:0% +a human, here's the range of the +tolerable accelerations between about 80 + + align:start position:0% +tolerable accelerations between about 80 + + + align:start position:0% +tolerable accelerations between about 80 +and 160 g. So you know I said around + + align:start position:0% +and 160 g. So you know I said around + + + align:start position:0% +and 160 g. So you know I said around +100. So we can take this curve and now + + align:start position:0% +100. So we can take this curve and now + + + align:start position:0% +100. So we can take this curve and now +we have this factor of 16 and we can + + align:start position:0% +we have this factor of 16 and we can + + + align:start position:0% +we have this factor of 16 and we can +just scale it up by our factor of 16 for + + align:start position:0% +just scale it up by our factor of 16 for + + + align:start position:0% +just scale it up by our factor of 16 for +the woodpecker. So if I scale it up by + + align:start position:0% +the woodpecker. So if I scale it up by + + + align:start position:0% +the woodpecker. So if I scale it up by +the factor of 16, we're there. But the + + align:start position:0% +the factor of 16, we're there. But the + + + align:start position:0% +the factor of 16, we're there. But the +the duration of the impacts was more + + align:start position:0% +the duration of the impacts was more + + + align:start position:0% +the duration of the impacts was more +around a half a millisecond to a + + align:start position:0% +around a half a millisecond to a + + + align:start position:0% +around a half a millisecond to a +millisecond. So I've extrapolated this a + + align:start position:0% +millisecond. So I've extrapolated this a + + + align:start position:0% +millisecond. So I've extrapolated this a +little bit and the duration of them is + + align:start position:0% +little bit and the duration of them is + + + align:start position:0% +little bit and the duration of them is +is up in here. So this is saying the + + align:start position:0% +is up in here. So this is saying the + + + align:start position:0% +is up in here. So this is saying the +woodpecker can take uh these sorts of + + align:start position:0% +woodpecker can take uh these sorts of + + + align:start position:0% +woodpecker can take uh these sorts of +decelerations here and that adds on + + align:start position:0% +decelerations here and that adds on + + + align:start position:0% +decelerations here and that adds on +another factor of four and these were + + align:start position:0% +another factor of four and these were + + + align:start position:0% +another factor of four and these were +the measured decelerations. They were + + align:start position:0% +the measured decelerations. They were + + + align:start position:0% +the measured decelerations. They were +sort of in 1500 was about the biggest + + align:start position:0% +sort of in 1500 was about the biggest + + + align:start position:0% +sort of in 1500 was about the biggest +and I think it went down to about few + + align:start position:0% +and I think it went down to about few + + + align:start position:0% +and I think it went down to about few +hundred g. So there's really three + + align:start position:0% +hundred g. So there's really three + + + align:start position:0% +hundred g. So there's really three +factors. One is the small brain size. So + + align:start position:0% +factors. One is the small brain size. So + + + align:start position:0% +factors. One is the small brain size. So +there's this sort of scaling factor. One + + align:start position:0% +there's this sort of scaling factor. One + + + align:start position:0% +there's this sort of scaling factor. One +is the orientation of the brain. That + + align:start position:0% +is the orientation of the brain. That + + + align:start position:0% +is the orientation of the brain. That +was another factor of two. And then + + align:start position:0% +was another factor of two. And then + + + align:start position:0% +was another factor of two. And then +there's this duration of impact which is + + align:start position:0% +there's this duration of impact which is + + + align:start position:0% +there's this duration of impact which is +a factor of four. And so that's how you + + align:start position:0% +a factor of four. And so that's how you + + + align:start position:0% +a factor of four. And so that's how you +can get this huge decelerations that + + align:start position:0% +can get this huge decelerations that + + + align:start position:0% +can get this huge decelerations that +they've measured in the woodpecker when + + align:start position:0% +they've measured in the woodpecker when + + + align:start position:0% +they've measured in the woodpecker when +they're pecking. Um so now I have just a + + align:start position:0% +they're pecking. Um so now I have just a + + + align:start position:0% +they're pecking. Um so now I have just a +couple more slides. So woodpeckers have + + align:start position:0% +couple more slides. So woodpeckers have + + + align:start position:0% +couple more slides. So woodpeckers have +various adaptations to pecking too. So + + align:start position:0% +various adaptations to pecking too. So + + + align:start position:0% +various adaptations to pecking too. So +one of the things is they have amazingly + + align:start position:0% +one of the things is they have amazingly + + + align:start position:0% +one of the things is they have amazingly +stiff tail feathers. You see the tails + + align:start position:0% +stiff tail feathers. You see the tails + + + align:start position:0% +stiff tail feathers. You see the tails +here? You can't quite see it because + + align:start position:0% +here? You can't quite see it because + + + align:start position:0% +here? You can't quite see it because +this didn't reproduce quite properly, + + align:start position:0% +this didn't reproduce quite properly, + + + align:start position:0% +this didn't reproduce quite properly, +but the the woodpecker is perched on a + + align:start position:0% +but the the woodpecker is perched on a + + + align:start position:0% +but the the woodpecker is perched on a +tree here and the tail is pressed up + + align:start position:0% +tree here and the tail is pressed up + + + align:start position:0% +tree here and the tail is pressed up +against the tree. And if you think about + + align:start position:0% +against the tree. And if you think about + + + align:start position:0% +against the tree. And if you think about +pecking, like imagine if its tail was + + align:start position:0% +pecking, like imagine if its tail was + + + align:start position:0% +pecking, like imagine if its tail was +not pressed up against the tree. It + + align:start position:0% +not pressed up against the tree. It + + + align:start position:0% +not pressed up against the tree. It +would be kind of grabbing on with its + + align:start position:0% +would be kind of grabbing on with its + + + align:start position:0% +would be kind of grabbing on with its +feet and it'd be trying to peck and it + + align:start position:0% +feet and it'd be trying to peck and it + + + align:start position:0% +feet and it'd be trying to peck and it +would be kind of hard to push. You know, + + align:start position:0% +would be kind of hard to push. You know, + + + align:start position:0% +would be kind of hard to push. You know, +you need something to push against. And + + align:start position:0% +you need something to push against. And + + + align:start position:0% +you need something to push against. And +so it's got these stiff tail feathers + + align:start position:0% +so it's got these stiff tail feathers + + + align:start position:0% +so it's got these stiff tail feathers +which make it easier to um to push + + align:start position:0% +which make it easier to um to push + + + align:start position:0% +which make it easier to um to push +against the tree. And so here's stiff + + align:start position:0% +against the tree. And so here's stiff + + + align:start position:0% +against the tree. And so here's stiff +tail feathers here. It's also got um + + align:start position:0% +tail feathers here. It's also got um + + + align:start position:0% +tail feathers here. It's also got um +kind of unusual feet for birds. It's got + + align:start position:0% +kind of unusual feet for birds. It's got + + + align:start position:0% +kind of unusual feet for birds. It's got +two toes forward and two toes back. And + + align:start position:0% +two toes forward and two toes back. And + + + align:start position:0% +two toes forward and two toes back. And +again, if it's grabbing with its feet, + + align:start position:0% +again, if it's grabbing with its feet, + + + align:start position:0% +again, if it's grabbing with its feet, +that helps it kind of get some perches + + align:start position:0% +that helps it kind of get some perches + + + align:start position:0% +that helps it kind of get some perches +to kind of push against. That's called + + align:start position:0% +to kind of push against. That's called + + + align:start position:0% +to kind of push against. That's called +zygodactyl in the bird world. So, it's + + align:start position:0% +zygodactyl in the bird world. So, it's + + + align:start position:0% +zygodactyl in the bird world. So, it's +got these adaptations to pecking. And + + align:start position:0% +got these adaptations to pecking. And + + + align:start position:0% +got these adaptations to pecking. And +then finally, I just like this slide + + align:start position:0% +then finally, I just like this slide + + + align:start position:0% +then finally, I just like this slide +here from the New Yorker because it's a + + align:start position:0% +here from the New Yorker because it's a + + + align:start position:0% +here from the New Yorker because it's a +woodpecker pecking out a woodpecker. So, + + align:start position:0% +woodpecker pecking out a woodpecker. So, + + + align:start position:0% +woodpecker pecking out a woodpecker. So, +it seemed kind of cute. And there's + + align:start position:0% +it seemed kind of cute. And there's + + + align:start position:0% +it seemed kind of cute. And there's +there's several people help me with this + + align:start position:0% +there's several people help me with this + + + align:start position:0% +there's several people help me with this +project. Trey Krisco studies head injury + + align:start position:0% +project. Trey Krisco studies head injury + + + align:start position:0% +project. Trey Krisco studies head injury +at Brown. He he actually does uh work + + align:start position:0% +at Brown. He he actually does uh work + + + align:start position:0% +at Brown. He he actually does uh work +for the NFL on football um brain + + align:start position:0% +for the NFL on football um brain + + + align:start position:0% +for the NFL on football um brain +injuries and looks at football helmets. + + align:start position:0% +injuries and looks at football helmets. + + + align:start position:0% +injuries and looks at football helmets. +Sharon Schwarz is a friend of mine at + + align:start position:0% +Sharon Schwarz is a friend of mine at + + + align:start position:0% +Sharon Schwarz is a friend of mine at +Brown who's a biologist. She studies bat + + align:start position:0% +Brown who's a biologist. She studies bat + + + align:start position:0% +Brown who's a biologist. She studies bat +flight and she just thought this was + + align:start position:0% +flight and she just thought this was + + + align:start position:0% +flight and she just thought this was +kind of a cool project. So, in fact, I + + align:start position:0% +kind of a cool project. So, in fact, I + + + align:start position:0% +kind of a cool project. So, in fact, I +was walking the dog last week, a few + + align:start position:0% +was walking the dog last week, a few + + + align:start position:0% +was walking the dog last week, a few +days ago, and I saw bats flying around + + align:start position:0% +days ago, and I saw bats flying around + + + align:start position:0% +days ago, and I saw bats flying around +overhead at night, and it was so great + + align:start position:0% +overhead at night, and it was so great + + + align:start position:0% +overhead at night, and it was so great +to see the little bats. Um, so I had to + + align:start position:0% +to see the little bats. Um, so I had to + + + align:start position:0% +to see the little bats. Um, so I had to +immediately email Sharon and say, "Bats, + + align:start position:0% +immediately email Sharon and say, "Bats, + + + align:start position:0% +immediately email Sharon and say, "Bats, +there's bats in my neighborhood." Andy + + align:start position:0% +there's bats in my neighborhood." Andy + + + align:start position:0% +there's bats in my neighborhood." Andy +Beewiner runs the um Conquered Field + + align:start position:0% +Beewiner runs the um Conquered Field + + + align:start position:0% +Beewiner runs the um Conquered Field +Station and studies animal locomotion, + + align:start position:0% +Station and studies animal locomotion, + + + align:start position:0% +Station and studies animal locomotion, +and I talked to him about it. Jeremy + + align:start position:0% +and I talked to him about it. Jeremy + + + align:start position:0% +and I talked to him about it. Jeremy +Trimble was the one who gave me the + + align:start position:0% +Trimble was the one who gave me the + + + align:start position:0% +Trimble was the one who gave me the +skull pictures, and Matt Dawson was a + + align:start position:0% +skull pictures, and Matt Dawson was a + + + align:start position:0% +skull pictures, and Matt Dawson was a +student who helped me do some of the + + align:start position:0% +student who helped me do some of the + + + align:start position:0% +student who helped me do some of the +images. So, that's my woodpecker talk. + + align:start position:0% +images. So, that's my woodpecker talk. + + + align:start position:0% +images. So, that's my woodpecker talk. +So, that's the end of energy absorption. + + align:start position:0% +So, that's the end of energy absorption. + + + align:start position:0% +So, that's the end of energy absorption. +I just thought that was kind of amusing. + + align:start position:0% +I just thought that was kind of amusing. + + + align:start position:0% +I just thought that was kind of amusing. +So, next time we'll start talking about + + align:start position:0% +So, next time we'll start talking about + + + align:start position:0% +So, next time we'll start talking about +sandwich panels. So, uh let's see. + + align:start position:0% +sandwich panels. So, uh let's see. + + + align:start position:0% +sandwich panels. So, uh let's see. +Monday's a holiday. I will be in Toronto + + align:start position:0% +Monday's a holiday. I will be in Toronto + + + align:start position:0% +Monday's a holiday. I will be in Toronto +on Monday seeing my family. In fact, I'm + + align:start position:0% +on Monday seeing my family. In fact, I'm + + + align:start position:0% +on Monday seeing my family. In fact, I'm +going to see one of my old professors. + + align:start position:0% +going to see one of my old professors. + + + align:start position:0% +going to see one of my old professors. +I'm going to see my old fluid mechanics + + align:start position:0% +I'm going to see my old fluid mechanics + + + align:start position:0% +I'm going to see my old fluid mechanics +professor on Monday and have lunch. See + + align:start position:0% +professor on Monday and have lunch. See + + + align:start position:0% +professor on Monday and have lunch. See +my family on the weekend. And uh so + + align:start position:0% +my family on the weekend. And uh so + + + align:start position:0% +my family on the weekend. And uh so +we'll meet Wednesday next week and I'll + + align:start position:0% +we'll meet Wednesday next week and I'll + + + align:start position:0% +we'll meet Wednesday next week and I'll +start the bit on sandwich panels. So I + + align:start position:0% +start the bit on sandwich panels. So I + + + align:start position:0% +start the bit on sandwich panels. So I +think there's two lectures on sort of + + align:start position:0% +think there's two lectures on sort of + + + align:start position:0% +think there's two lectures on sort of +engineering sandwich panels and then + + align:start position:0% +engineering sandwich panels and then + + + align:start position:0% +engineering sandwich panels and then +there's a lecture on natural sandwich + + align:start position:0% +there's a lecture on natural sandwich + + + align:start position:0% +there's a lecture on natural sandwich +panels. Uh so bird skulls for example or + + align:start position:0% +panels. Uh so bird skulls for example or + + + align:start position:0% +panels. Uh so bird skulls for example or +natural sandwich panels. So I'll talk + + align:start position:0% +natural sandwich panels. So I'll talk + + + align:start position:0% +natural sandwich panels. So I'll talk +about that and then I think the last + + align:start position:0% +about that and then I think the last + + + align:start position:0% +about that and then I think the last +lecture we're getting like there's only + + align:start position:0% +lecture we're getting like there's only + + + align:start position:0% +lecture we're getting like there's only +a handful of lectures left. The last one + + align:start position:0% +a handful of lectures left. The last one + + + align:start position:0% +a handful of lectures left. The last one +I think I talk about natural materials + + align:start position:0% +I think I talk about natural materials + + + align:start position:0% +I think I talk about natural materials +because you know I like that so I just + + align:start position:0% +because you know I like that so I just + + + align:start position:0% +because you know I like that so I just +do that for fun. \ No newline at end of file diff --git a/ymsbTVLbyN4.txt b/ymsbTVLbyN4.txt new file mode 100644 index 0000000000000000000000000000000000000000..1ad99e8750768d665356ec3e695a5b02a137fd60 --- /dev/null +++ b/ymsbTVLbyN4.txt @@ -0,0 +1,13891 @@ +align:start position:0% + +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +Well, so far in this course we've been + + align:start position:0% +Well, so far in this course we've been + + + align:start position:0% +Well, so far in this course we've been +talking about procedures + + align:start position:0% +talking about procedures + + + align:start position:0% +talking about procedures +and then just to remind you of this + + align:start position:0% +and then just to remind you of this + + + align:start position:0% +and then just to remind you of this +framework that that we introduced for + + align:start position:0% +framework that that we introduced for + + + align:start position:0% +framework that that we introduced for +talking about languages. We talked about + + align:start position:0% +talking about languages. We talked about + + + align:start position:0% +talking about languages. We talked about +the primitive things that are built into + + align:start position:0% +the primitive things that are built into + + + align:start position:0% +the primitive things that are built into +the system. Uh we mentioned some means + + align:start position:0% +the system. Uh we mentioned some means + + + align:start position:0% +the system. Uh we mentioned some means +of combination + + align:start position:0% +of combination + + + align:start position:0% +of combination +by which you take the primitive things + + align:start position:0% +by which you take the primitive things + + + align:start position:0% +by which you take the primitive things +and you make more complicated things. + + align:start position:0% +and you make more complicated things. + + + align:start position:0% +and you make more complicated things. +And then we talked about the means of + + align:start position:0% +And then we talked about the means of + + + align:start position:0% +And then we talked about the means of +abstraction. How you can take those + + align:start position:0% +abstraction. How you can take those + + + align:start position:0% +abstraction. How you can take those +complicated things and name them. So you + + align:start position:0% +complicated things and name them. So you + + + align:start position:0% +complicated things and name them. So you +can use them as simple building blocks. + + align:start position:0% +can use them as simple building blocks. + + + align:start position:0% +can use them as simple building blocks. +And then last time you saw we went even + + align:start position:0% +And then last time you saw we went even + + + align:start position:0% +And then last time you saw we went even +beyond that. We saw that by using higher + + align:start position:0% +beyond that. We saw that by using higher + + + align:start position:0% +beyond that. We saw that by using higher +order procedures, + + align:start position:0% +order procedures, + + + align:start position:0% +order procedures, +you can actually express general methods + + align:start position:0% +you can actually express general methods + + + align:start position:0% +you can actually express general methods +for computing things like the method of + + align:start position:0% +for computing things like the method of + + + align:start position:0% +for computing things like the method of +doing something by fixed points or + + align:start position:0% +doing something by fixed points or + + + align:start position:0% +doing something by fixed points or +Newton's method. And so the the + + align:start position:0% +Newton's method. And so the the + + + align:start position:0% +Newton's method. And so the the +incredible expressive power you can get + + align:start position:0% +incredible expressive power you can get + + + align:start position:0% +incredible expressive power you can get +just by combining these these means of + + align:start position:0% +just by combining these these means of + + + align:start position:0% +just by combining these these means of +abstraction. And the crucial idea in all + + align:start position:0% +abstraction. And the crucial idea in all + + + align:start position:0% +abstraction. And the crucial idea in all +of this is the one that we build a + + align:start position:0% +of this is the one that we build a + + + align:start position:0% +of this is the one that we build a +layered system. So for instance if we're + + align:start position:0% +layered system. So for instance if we're + + + align:start position:0% +layered system. So for instance if we're +writing the square root procedure + + align:start position:0% + + + + align:start position:0% + +somewhere the square root procedure uses + + align:start position:0% +somewhere the square root procedure uses + + + align:start position:0% +somewhere the square root procedure uses +a procedure called good enough + + align:start position:0% + + + + align:start position:0% + +and between those there's some sort of + + align:start position:0% +and between those there's some sort of + + + align:start position:0% +and between those there's some sort of +abstraction boundary. + + align:start position:0% + + + + align:start position:0% + +It's almost as if uh we go out and in + + align:start position:0% +It's almost as if uh we go out and in + + + align:start position:0% +It's almost as if uh we go out and in +writing square root, we go and make a + + align:start position:0% +writing square root, we go and make a + + + align:start position:0% +writing square root, we go and make a +contract with uh with George and tell + + align:start position:0% +contract with uh with George and tell + + + align:start position:0% +contract with uh with George and tell +George that his job is to write good + + align:start position:0% +George that his job is to write good + + + align:start position:0% +George that his job is to write good +enough. + + align:start position:0% +enough. + + + align:start position:0% +enough. +And so long as good enough works, we + + align:start position:0% +And so long as good enough works, we + + + align:start position:0% +And so long as good enough works, we +don't care what it does. We don't care + + align:start position:0% +don't care what it does. We don't care + + + align:start position:0% +don't care what it does. We don't care +exactly how it's implemented. There are + + align:start position:0% +exactly how it's implemented. There are + + + align:start position:0% +exactly how it's implemented. There are +levels of detail here that are George's + + align:start position:0% +levels of detail here that are George's + + + align:start position:0% +levels of detail here that are George's +concern and not ours. + + align:start position:0% +concern and not ours. + + + align:start position:0% +concern and not ours. +So for instance, George might use uh an + + align:start position:0% +So for instance, George might use uh an + + + align:start position:0% +So for instance, George might use uh an +absolute value procedure that's written + + align:start position:0% +absolute value procedure that's written + + + align:start position:0% +absolute value procedure that's written +by Harry and we don't much care about + + align:start position:0% +by Harry and we don't much care about + + + align:start position:0% +by Harry and we don't much care about +that or even know that that maybe Harry + + align:start position:0% +that or even know that that maybe Harry + + + align:start position:0% +that or even know that that maybe Harry +exists. + + align:start position:0% + + + + align:start position:0% + +So the crucial idea is that when we're + + align:start position:0% +So the crucial idea is that when we're + + + align:start position:0% +So the crucial idea is that when we're +building things, we divorce the task of + + align:start position:0% +building things, we divorce the task of + + + align:start position:0% +building things, we divorce the task of +building things + + align:start position:0% +building things + + + align:start position:0% +building things +from the task of implementing the parts. + + align:start position:0% + + + + align:start position:0% + +It's as if and then in a large system of + + align:start position:0% +It's as if and then in a large system of + + + align:start position:0% +It's as if and then in a large system of +course we have abstraction barriers like + + align:start position:0% +course we have abstraction barriers like + + + align:start position:0% +course we have abstraction barriers like +this at lots and lots and lots of levels + + align:start position:0% +this at lots and lots and lots of levels + + + align:start position:0% +this at lots and lots and lots of levels +and that's the idea that we've been + + align:start position:0% +and that's the idea that we've been + + + align:start position:0% +and that's the idea that we've been +using so far over and over in + + align:start position:0% +using so far over and over in + + + align:start position:0% +using so far over and over in +implementing procedures. Well, now what + + align:start position:0% +implementing procedures. Well, now what + + + align:start position:0% +implementing procedures. Well, now what +we're going to do is look at the same + + align:start position:0% +we're going to do is look at the same + + + align:start position:0% +we're going to do is look at the same +issues for data. + + align:start position:0% +issues for data. + + + align:start position:0% +issues for data. +We're going to see that the system has + + align:start position:0% +We're going to see that the system has + + + align:start position:0% +We're going to see that the system has +primitive data. In fact, we've already + + align:start position:0% +primitive data. In fact, we've already + + + align:start position:0% +primitive data. In fact, we've already +seen that. We've talked about numbers as + + align:start position:0% +seen that. We've talked about numbers as + + + align:start position:0% +seen that. We've talked about numbers as +primitive data. And then we're going to + + align:start position:0% +primitive data. And then we're going to + + + align:start position:0% +primitive data. And then we're going to +see their means of combination for data. + + align:start position:0% +see their means of combination for data. + + + align:start position:0% +see their means of combination for data. +There's glue that allows you to put + + align:start position:0% +There's glue that allows you to put + + + align:start position:0% +There's glue that allows you to put +primitive data together to make more + + align:start position:0% +primitive data together to make more + + + align:start position:0% +primitive data together to make more +complicated kind of compound data. And + + align:start position:0% +complicated kind of compound data. And + + + align:start position:0% +complicated kind of compound data. And +then we're going to see a methodology + + align:start position:0% +then we're going to see a methodology + + + align:start position:0% +then we're going to see a methodology +for abstraction. + + align:start position:0% +for abstraction. + + + align:start position:0% +for abstraction. +That's a very good thing to use when you + + align:start position:0% +That's a very good thing to use when you + + + align:start position:0% +That's a very good thing to use when you +start building up data in terms of + + align:start position:0% +start building up data in terms of + + + align:start position:0% +start building up data in terms of +simpler data. And again, the key idea is + + align:start position:0% +simpler data. And again, the key idea is + + + align:start position:0% +simpler data. And again, the key idea is +that you're going to build this system + + align:start position:0% +that you're going to build this system + + + align:start position:0% +that you're going to build this system +in layers and set up abstraction + + align:start position:0% +in layers and set up abstraction + + + align:start position:0% +in layers and set up abstraction +barriers that isolate the details at the + + align:start position:0% +barriers that isolate the details at the + + + align:start position:0% +barriers that isolate the details at the +lower layers + + align:start position:0% +lower layers + + + align:start position:0% +lower layers +from the thing that's going on at the + + align:start position:0% +from the thing that's going on at the + + + align:start position:0% +from the thing that's going on at the +upper layers. the details at the lower + + align:start position:0% +upper layers. the details at the lower + + + align:start position:0% +upper layers. the details at the lower +layers, the idea is they won't matter. + + align:start position:0% +layers, the idea is they won't matter. + + + align:start position:0% +layers, the idea is they won't matter. +They're going to be George's concern + + align:start position:0% +They're going to be George's concern + + + align:start position:0% +They're going to be George's concern +because he signed this contract with us + + align:start position:0% +because he signed this contract with us + + + align:start position:0% +because he signed this contract with us +for how the stuff that he implements + + align:start position:0% +for how the stuff that he implements + + + align:start position:0% +for how the stuff that he implements +behaves. And how he implements the thing + + align:start position:0% +behaves. And how he implements the thing + + + align:start position:0% +behaves. And how he implements the thing +is his problem. + + align:start position:0% +is his problem. + + + align:start position:0% +is his problem. +All right. Well, let's look at an + + align:start position:0% +All right. Well, let's look at an + + + align:start position:0% +All right. Well, let's look at an +example. And the example I'm going to + + align:start position:0% +example. And the example I'm going to + + + align:start position:0% +example. And the example I'm going to +talk about is a system that does + + align:start position:0% +talk about is a system that does + + + align:start position:0% +talk about is a system that does +arithmetic on rational numbers. And what + + align:start position:0% +arithmetic on rational numbers. And what + + + align:start position:0% +arithmetic on rational numbers. And what +I have in mind is that we should have + + align:start position:0% +I have in mind is that we should have + + + align:start position:0% +I have in mind is that we should have +something in the computer that allows us + + align:start position:0% +something in the computer that allows us + + + align:start position:0% +something in the computer that allows us +to + + align:start position:0% +to + + + align:start position:0% +to +ask it like u what's the sum of a half + + align:start position:0% +ask it like u what's the sum of a half + + + align:start position:0% +ask it like u what's the sum of a half +and a fourth and somehow the system + + align:start position:0% +and a fourth and somehow the system + + + align:start position:0% +and a fourth and somehow the system +should say + + align:start position:0% + + + + align:start position:0% + +say yeah that's 3/4s + + align:start position:0% +say yeah that's 3/4s + + + align:start position:0% +say yeah that's 3/4s +or uh we should be able to say what's + + align:start position:0% +or uh we should be able to say what's + + + align:start position:0% +or uh we should be able to say what's +3/4s + + align:start position:0% +3/4s + + + align:start position:0% +3/4s +times + + align:start position:0% +times + + + align:start position:0% +times +2/3 + + align:start position:0% +2/3 + + + align:start position:0% +2/3 +and the system should be able to say, + + align:start position:0% +and the system should be able to say, + + + align:start position:0% +and the system should be able to say, +"Yeah, that's a half, + + align:start position:0% +"Yeah, that's a half, + + + align:start position:0% +"Yeah, that's a half, +right?" And you know what I have in + + align:start position:0% +right?" And you know what I have in + + + align:start position:0% +right?" And you know what I have in +mind, and you also know how to do this + + align:start position:0% +mind, and you also know how to do this + + + align:start position:0% +mind, and you also know how to do this +from uh I don't know, fifth grade or + + align:start position:0% +from uh I don't know, fifth grade or + + + align:start position:0% +from uh I don't know, fifth grade or +sixth grade. There are these formulas + + align:start position:0% +sixth grade. There are these formulas + + + align:start position:0% +sixth grade. There are these formulas +that say if I have some fraction + + align:start position:0% +that say if I have some fraction + + + align:start position:0% +that say if I have some fraction +which is a numerator over a denominator + + align:start position:0% +which is a numerator over a denominator + + + align:start position:0% +which is a numerator over a denominator +and I want to add that to some other + + align:start position:0% +and I want to add that to some other + + + align:start position:0% +and I want to add that to some other +fraction which is another numerator over + + align:start position:0% +fraction which is another numerator over + + + align:start position:0% +fraction which is another numerator over +another denominator. Then the answer is + + align:start position:0% +another denominator. Then the answer is + + + align:start position:0% +another denominator. Then the answer is +the numerator of the first time the + + align:start position:0% +the numerator of the first time the + + + align:start position:0% +the numerator of the first time the +denominator of the second plus the uh + + align:start position:0% +denominator of the second plus the uh + + + align:start position:0% +denominator of the second plus the uh +numerator of the second time the + + align:start position:0% +numerator of the second time the + + + align:start position:0% +numerator of the second time the +denominator of the first. + + align:start position:0% +denominator of the first. + + + align:start position:0% +denominator of the first. +That's the numerator of the answer and + + align:start position:0% +That's the numerator of the answer and + + + align:start position:0% +That's the numerator of the answer and +the denominator is the product of the + + align:start position:0% +the denominator is the product of the + + + align:start position:0% +the denominator is the product of the +two denominators. Right? So there's + + align:start position:0% +two denominators. Right? So there's + + + align:start position:0% +two denominators. Right? So there's +something from fifth or sixth grade + + align:start position:0% +something from fifth or sixth grade + + + align:start position:0% +something from fifth or sixth grade +fraction arithmetic. And then similarly, + + align:start position:0% +fraction arithmetic. And then similarly, + + + align:start position:0% +fraction arithmetic. And then similarly, +if I want to multiply two things, n1 + + align:start position:0% +if I want to multiply two things, n1 + + + align:start position:0% +if I want to multiply two things, n1 +over d1 multiplied by n2 over d2 is the + + align:start position:0% +over d1 multiplied by n2 over d2 is the + + + align:start position:0% +over d1 multiplied by n2 over d2 is the +product of the numerators + + align:start position:0% +product of the numerators + + + align:start position:0% +product of the numerators +over the product of the denominators. + + align:start position:0% + + + + align:start position:0% + +So it's no problem at all, but it's + + align:start position:0% +So it's no problem at all, but it's + + + align:start position:0% +So it's no problem at all, but it's +absolutely no problem to to think about + + align:start position:0% +absolutely no problem to to think about + + + align:start position:0% +absolutely no problem to to think about +what computation you want to make in + + align:start position:0% +what computation you want to make in + + + align:start position:0% +what computation you want to make in +adding and multiplying these fractions. + + align:start position:0% +adding and multiplying these fractions. + + + align:start position:0% +adding and multiplying these fractions. +But as soon as we go to implement it, we + + align:start position:0% +But as soon as we go to implement it, we + + + align:start position:0% +But as soon as we go to implement it, we +run up across something. We don't have + + align:start position:0% +run up across something. We don't have + + + align:start position:0% +run up across something. We don't have +what a rational number is. + + align:start position:0% +what a rational number is. + + + align:start position:0% +what a rational number is. +See, we've said that the system gives us + + align:start position:0% +See, we've said that the system gives us + + + align:start position:0% +See, we've said that the system gives us +individual numbers. So we can have five + + align:start position:0% +individual numbers. So we can have five + + + align:start position:0% +individual numbers. So we can have five +and three, but but somehow we don't have + + align:start position:0% +and three, but but somehow we don't have + + + align:start position:0% +and three, but but somehow we don't have +a way of of saying there's a thing that + + align:start position:0% +a way of of saying there's a thing that + + + align:start position:0% +a way of of saying there's a thing that +has, you know, both a three and a four + + align:start position:0% +has, you know, both a three and a four + + + align:start position:0% +has, you know, both a three and a four +in it or both a both a two and a three. + + align:start position:0% +in it or both a both a two and a three. + + + align:start position:0% +in it or both a both a two and a three. +It's almost as if + + align:start position:0% +It's almost as if + + + align:start position:0% +It's almost as if +we'd like to imagine that somehow there + + align:start position:0% +we'd like to imagine that somehow there + + + align:start position:0% +we'd like to imagine that somehow there +are these clouds + + align:start position:0% +are these clouds + + + align:start position:0% +are these clouds +and a cloud somehow has both a numerator + + align:start position:0% +and a cloud somehow has both a numerator + + + align:start position:0% +and a cloud somehow has both a numerator +and a denominator in it. And that's what + + align:start position:0% +and a denominator in it. And that's what + + + align:start position:0% +and a denominator in it. And that's what +we'd like to work in terms of. + + align:start position:0% +we'd like to work in terms of. + + + align:start position:0% +we'd like to work in terms of. +Well, how are we going to solve that + + align:start position:0% +Well, how are we going to solve that + + + align:start position:0% +Well, how are we going to solve that +problem? We're going to solve that + + align:start position:0% +problem? We're going to solve that + + + align:start position:0% +problem? We're going to solve that +problem by using this incredibly + + align:start position:0% +problem by using this incredibly + + + align:start position:0% +problem by using this incredibly +powerful design strategy that you've + + align:start position:0% +powerful design strategy that you've + + + align:start position:0% +powerful design strategy that you've +already seen us use over and over. And + + align:start position:0% +already seen us use over and over. And + + + align:start position:0% +already seen us use over and over. And +that's the strategy of wishful thinking. + + align:start position:0% + + + + align:start position:0% + +Just like before when we didn't have a + + align:start position:0% +Just like before when we didn't have a + + + align:start position:0% +Just like before when we didn't have a +procedure, we said, well, let's imagine + + align:start position:0% +procedure, we said, well, let's imagine + + + align:start position:0% +procedure, we said, well, let's imagine +that that procedure already exists. + + align:start position:0% +that that procedure already exists. + + + align:start position:0% +that that procedure already exists. +We'll say well let's imagine that we + + align:start position:0% +We'll say well let's imagine that we + + + align:start position:0% +We'll say well let's imagine that we +have these clouds + + align:start position:0% +have these clouds + + + align:start position:0% +have these clouds +now more precisely what I mean is + + align:start position:0% +now more precisely what I mean is + + + align:start position:0% +now more precisely what I mean is +let's imagine that we have three + + align:start position:0% +let's imagine that we have three + + + align:start position:0% +let's imagine that we have three +procedures + + align:start position:0% +procedures + + + align:start position:0% +procedures +one called makerat + + align:start position:0% + + + + align:start position:0% + +makerat is going to take as arguments + + align:start position:0% +makerat is going to take as arguments + + + align:start position:0% +makerat is going to take as arguments +two numbers + + align:start position:0% +two numbers + + + align:start position:0% +two numbers +which I'll call numerator and + + align:start position:0% +which I'll call numerator and + + + align:start position:0% +which I'll call numerator and +denominator + + align:start position:0% +denominator + + + align:start position:0% +denominator +and it'll return for us + + align:start position:0% +and it'll return for us + + + align:start position:0% +and it'll return for us +a cloud, + + align:start position:0% +a cloud, + + + align:start position:0% +a cloud, +right? One of these clouds. + + align:start position:0% +right? One of these clouds. + + + align:start position:0% +right? One of these clouds. +I don't really know what a cloud is. + + align:start position:0% +I don't really know what a cloud is. + + + align:start position:0% +I don't really know what a cloud is. +It's whatever Makeat returns. That's its + + align:start position:0% +It's whatever Makeat returns. That's its + + + align:start position:0% +It's whatever Makeat returns. That's its +business. + + align:start position:0% +business. + + + align:start position:0% +business. +And then we're going to say suppose + + align:start position:0% +And then we're going to say suppose + + + align:start position:0% +And then we're going to say suppose +we've got one of these clouds. We have a + + align:start position:0% +we've got one of these clouds. We have a + + + align:start position:0% +we've got one of these clouds. We have a +procedure called numer + + align:start position:0% +procedure called numer + + + align:start position:0% +procedure called numer +which takes in a cloud that has an n and + + align:start position:0% +which takes in a cloud that has an n and + + + align:start position:0% +which takes in a cloud that has an n and +a d in it. Whatever a cloud is and I + + align:start position:0% +a d in it. Whatever a cloud is and I + + + align:start position:0% +a d in it. Whatever a cloud is and I +don't know what it is, and returns for + + align:start position:0% +don't know what it is, and returns for + + + align:start position:0% +don't know what it is, and returns for +us the numerator part. + + align:start position:0% +us the numerator part. + + + align:start position:0% +us the numerator part. +And then we'll assume we have a + + align:start position:0% +And then we'll assume we have a + + + align:start position:0% +And then we'll assume we have a +procedure denom + + align:start position:0% +procedure denom + + + align:start position:0% +procedure denom +which again takes in a cloud whatever a + + align:start position:0% +which again takes in a cloud whatever a + + + align:start position:0% +which again takes in a cloud whatever a +cloud is + + align:start position:0% +cloud is + + + align:start position:0% +cloud is +and returns for us the denominator + + align:start position:0% +and returns for us the denominator + + + align:start position:0% +and returns for us the denominator +report. This is just like before when if + + align:start position:0% +report. This is just like before when if + + + align:start position:0% +report. This is just like before when if +we're building a square root, we assume + + align:start position:0% +we're building a square root, we assume + + + align:start position:0% +we're building a square root, we assume +that we have good enough, right? And + + align:start position:0% +that we have good enough, right? And + + + align:start position:0% +that we have good enough, right? And +what we'll say is we'll go find George. + + align:start position:0% +what we'll say is we'll go find George. + + + align:start position:0% +what we'll say is we'll go find George. +We'll say to George, well, it's your + + align:start position:0% +We'll say to George, well, it's your + + + align:start position:0% +We'll say to George, well, it's your +business to make us these procedures + + align:start position:0% +business to make us these procedures + + + align:start position:0% +business to make us these procedures +and how you choose to implement these + + align:start position:0% +and how you choose to implement these + + + align:start position:0% +and how you choose to implement these +clouds, that's your problem. We don't + + align:start position:0% +clouds, that's your problem. We don't + + + align:start position:0% +clouds, that's your problem. We don't +want to know. + + align:start position:0% + + + + align:start position:0% + +Well, having pushed this task off onto + + align:start position:0% +Well, having pushed this task off onto + + + align:start position:0% +Well, having pushed this task off onto +George, then it's pretty easy to do the + + align:start position:0% +George, then it's pretty easy to do the + + + align:start position:0% +George, then it's pretty easy to do the +other part. Once we've got the clouds, + + align:start position:0% +other part. Once we've got the clouds, + + + align:start position:0% +other part. Once we've got the clouds, +it's pretty easy to write the thing that + + align:start position:0% +it's pretty easy to write the thing that + + + align:start position:0% +it's pretty easy to write the thing that +does say addition of rational numbers + + align:start position:0% +does say addition of rational numbers + + + align:start position:0% +does say addition of rational numbers +can just say define + + align:start position:0% + + + + align:start position:0% + +well let's say uh plus rat + + align:start position:0% + + + + align:start position:0% + +define plus rat which will take in two + + align:start position:0% +define plus rat which will take in two + + + align:start position:0% +define plus rat which will take in two +rational numbers + + align:start position:0% +rational numbers + + + align:start position:0% +rational numbers +x and y x and y are each these clouds + + align:start position:0% +x and y x and y are each these clouds + + + align:start position:0% +x and y x and y are each these clouds +and what does it do? Well, it's going to + + align:start position:0% +and what does it do? Well, it's going to + + + align:start position:0% +and what does it do? Well, it's going to +return for us a rational number. + + align:start position:0% + + + + align:start position:0% + +What rational number is it? Well, we've + + align:start position:0% +What rational number is it? Well, we've + + + align:start position:0% +What rational number is it? Well, we've +got the formulas there. The numerator of + + align:start position:0% +got the formulas there. The numerator of + + + align:start position:0% +got the formulas there. The numerator of +it is the sum of + + align:start position:0% +it is the sum of + + + align:start position:0% +it is the sum of +the product + + align:start position:0% +the product + + + align:start position:0% +the product +of the numerator + + align:start position:0% +of the numerator + + + align:start position:0% +of the numerator +of x + + align:start position:0% +of x + + + align:start position:0% +of x +and the denominator of y. + + align:start position:0% + + + + align:start position:0% + +It's one thing in the sum and the other + + align:start position:0% +It's one thing in the sum and the other + + + align:start position:0% +It's one thing in the sum and the other +thing in the numerator is the product of + + align:start position:0% +thing in the numerator is the product of + + + align:start position:0% +thing in the numerator is the product of +the numerator + + align:start position:0% + + + + align:start position:0% + +of y + + align:start position:0% +of y + + + align:start position:0% +of y +and the denominator + + align:start position:0% + + + + align:start position:0% + +of x + + align:start position:0% +of x + + + align:start position:0% +of x +close the star close the plus right + + align:start position:0% +close the star close the plus right + + + align:start position:0% +close the star close the plus right +that's the the first argument to make + + align:start position:0% +that's the the first argument to make + + + align:start position:0% +that's the the first argument to make +which is the numerator of the thing I'm + + align:start position:0% +which is the numerator of the thing I'm + + + align:start position:0% +which is the numerator of the thing I'm +constructing and then the rest of the + + align:start position:0% +constructing and then the rest of the + + + align:start position:0% +constructing and then the rest of the +thing goes into makerat is the denom + + align:start position:0% +thing goes into makerat is the denom + + + align:start position:0% +thing goes into makerat is the denom +denominator of the answer which is the + + align:start position:0% +denominator of the answer which is the + + + align:start position:0% +denominator of the answer which is the +product of the denominator + + align:start position:0% +product of the denominator + + + align:start position:0% +product of the denominator +of x and the denominator + + align:start position:0% +of x and the denominator + + + align:start position:0% +of x and the denominator +of y + + align:start position:0% +of y + + + align:start position:0% +of y +like that. + + align:start position:0% + + + + align:start position:0% + +Okay, so there is there's the analog of + + align:start position:0% +Okay, so there is there's the analog of + + + align:start position:0% +Okay, so there is there's the analog of +of doing rational number addition and + + align:start position:0% +of doing rational number addition and + + + align:start position:0% +of doing rational number addition and +it's no problem at all assuming that we + + align:start position:0% +it's no problem at all assuming that we + + + align:start position:0% +it's no problem at all assuming that we +have these clouds + + align:start position:0% + + + + align:start position:0% + +and of course we can do uh + + align:start position:0% +and of course we can do uh + + + align:start position:0% +and of course we can do uh +multiplication in the same way + + align:start position:0% + + + + align:start position:0% + +I define + + align:start position:0% +I define + + + align:start position:0% +I define +how to get the product of two rational + + align:start position:0% +how to get the product of two rational + + + align:start position:0% +how to get the product of two rational +numbers call it star rat takes in two of + + align:start position:0% +numbers call it star rat takes in two of + + + align:start position:0% +numbers call it star rat takes in two of +these clouds x and y. + + align:start position:0% + + + + align:start position:0% + +It returns a rational number make rat + + align:start position:0% +It returns a rational number make rat + + + align:start position:0% +It returns a rational number make rat +whose numerator is the product of the + + align:start position:0% +whose numerator is the product of the + + + align:start position:0% +whose numerator is the product of the +numerators + + align:start position:0% + + + + align:start position:0% + +numerator at x times the numerator + + align:start position:0% +numerator at x times the numerator + + + align:start position:0% +numerator at x times the numerator +of y. + + align:start position:0% +of y. + + + align:start position:0% +of y. +And the denominator of the thing it's + + align:start position:0% +And the denominator of the thing it's + + + align:start position:0% +And the denominator of the thing it's +going to return is the product of the + + align:start position:0% +going to return is the product of the + + + align:start position:0% +going to return is the product of the +denominators. + + align:start position:0% + + + + align:start position:0% + +Okay. Well, + + align:start position:0% +Okay. Well, + + + align:start position:0% +Okay. Well, +except that I haven't told you what + + align:start position:0% +except that I haven't told you what + + + align:start position:0% +except that I haven't told you what +these clouds are. That's all there is to + + align:start position:0% +these clouds are. That's all there is to + + + align:start position:0% +these clouds are. That's all there is to +it. See, what did I do? I assumed by + + align:start position:0% +it. See, what did I do? I assumed by + + + align:start position:0% +it. See, what did I do? I assumed by +wishful thinking that I had a new kind + + align:start position:0% +wishful thinking that I had a new kind + + + align:start position:0% +wishful thinking that I had a new kind +of data object and in particular I + + align:start position:0% +of data object and in particular I + + + align:start position:0% +of data object and in particular I +assumed I had ways of creating these + + align:start position:0% +assumed I had ways of creating these + + + align:start position:0% +assumed I had ways of creating these +data objects. Make rat creates one of + + align:start position:0% +data objects. Make rat creates one of + + + align:start position:0% +data objects. Make rat creates one of +these things. This is called a + + align:start position:0% +these things. This is called a + + + align:start position:0% +these things. This is called a +constructor. + + align:start position:0% + + + + align:start position:0% + +I had a thing that that constructs such + + align:start position:0% +I had a thing that that constructs such + + + align:start position:0% +I had a thing that that constructs such +data objects and then I assume I have + + align:start position:0% +data objects and then I assume I have + + + align:start position:0% +data objects and then I assume I have +things that having made these things I + + align:start position:0% +things that having made these things I + + + align:start position:0% +things that having made these things I +have ways of getting the parts out. + + align:start position:0% +have ways of getting the parts out. + + + align:start position:0% +have ways of getting the parts out. +Those are called selectors. + + align:start position:0% + + + + align:start position:0% + +Right? So formally what I said is I + + align:start position:0% +Right? So formally what I said is I + + + align:start position:0% +Right? So formally what I said is I +assumed I had procedures that are + + align:start position:0% +assumed I had procedures that are + + + align:start position:0% +assumed I had procedures that are +constructors and selectors for these + + align:start position:0% +constructors and selectors for these + + + align:start position:0% +constructors and selectors for these +data objects and then I went off and + + align:start position:0% +data objects and then I went off and + + + align:start position:0% +data objects and then I went off and +used them. + + align:start position:0% +used them. + + + align:start position:0% +used them. +And that's no different in kind from + + align:start position:0% +And that's no different in kind from + + + align:start position:0% +And that's no different in kind from +saying I assume I have a procedure good + + align:start position:0% +saying I assume I have a procedure good + + + align:start position:0% +saying I assume I have a procedure good +enough and I go use it to implement + + align:start position:0% +enough and I go use it to implement + + + align:start position:0% +enough and I go use it to implement +square root. + + align:start position:0% +square root. + + + align:start position:0% +square root. +Okay. Well, before we go on, + + align:start position:0% + + + + align:start position:0% + +let's ask the question of why we want to + + align:start position:0% +let's ask the question of why we want to + + + align:start position:0% +let's ask the question of why we want to +why we want to do this in the first + + align:start position:0% +why we want to do this in the first + + + align:start position:0% +why we want to do this in the first +place. See, why do we want a procedure + + align:start position:0% +place. See, why do we want a procedure + + + align:start position:0% +place. See, why do we want a procedure +like uh like plus rat that takes in two + + align:start position:0% +like uh like plus rat that takes in two + + + align:start position:0% +like uh like plus rat that takes in two +rational numbers and returns a rational + + align:start position:0% +rational numbers and returns a rational + + + align:start position:0% +rational numbers and returns a rational +number. See, another way to think about + + align:start position:0% +number. See, another way to think about + + + align:start position:0% +number. See, another way to think about +this is well, here's this formula. + + align:start position:0% +this is well, here's this formula. + + + align:start position:0% +this is well, here's this formula. +And what I if I was going to implement, + + align:start position:0% +And what I if I was going to implement, + + + align:start position:0% +And what I if I was going to implement, +you know, something that adds rational + + align:start position:0% +you know, something that adds rational + + + align:start position:0% +you know, something that adds rational +numbers, one other way to think about it + + align:start position:0% +numbers, one other way to think about it + + + align:start position:0% +numbers, one other way to think about it +is, well, there's this thing, and I type + + align:start position:0% +is, well, there's this thing, and I type + + + align:start position:0% +is, well, there's this thing, and I type +in four numbers, an n1 and a d1 and an + + align:start position:0% +in four numbers, an n1 and a d1 and an + + + align:start position:0% +in four numbers, an n1 and a d1 and an +n2 and a d2, and it sets some registers + + align:start position:0% +n2 and a d2, and it sets some registers + + + align:start position:0% +n2 and a d2, and it sets some registers +in the machine to uh + + align:start position:0% +in the machine to uh + + + align:start position:0% +in the machine to uh +this numerator and this denominator. So + + align:start position:0% +this numerator and this denominator. So + + + align:start position:0% +this numerator and this denominator. So +I might say, well, why don't I just add + + align:start position:0% +I might say, well, why don't I just add + + + align:start position:0% +I might say, well, why don't I just add +rational numbers by I type in four + + align:start position:0% +rational numbers by I type in four + + + align:start position:0% +rational numbers by I type in four +numbers, numerators and denominators, + + align:start position:0% +numbers, numerators and denominators, + + + align:start position:0% +numbers, numerators and denominators, +and get out two numbers, which is a + + align:start position:0% +and get out two numbers, which is a + + + align:start position:0% +and get out two numbers, which is a +numerator and a denominator, + + align:start position:0% +numerator and a denominator, + + + align:start position:0% +numerator and a denominator, +right? Why why are we worrying about + + align:start position:0% +right? Why why are we worrying about + + + align:start position:0% +right? Why why are we worrying about +building things like this anyway? + + align:start position:0% + + + + align:start position:0% + +Well, the answer is suppose you want to + + align:start position:0% +Well, the answer is suppose you want to + + + align:start position:0% +Well, the answer is suppose you want to +think about expressing something like uh + + align:start position:0% +think about expressing something like uh + + + align:start position:0% +think about expressing something like uh +like this. Suppose I'd like to express + + align:start position:0% +like this. Suppose I'd like to express + + + align:start position:0% +like this. Suppose I'd like to express +the idea of taking two rational numbers + + align:start position:0% +the idea of taking two rational numbers + + + align:start position:0% +the idea of taking two rational numbers +x + y say and multiplying that by the + + align:start position:0% +x + y say and multiplying that by the + + + align:start position:0% +x + y say and multiplying that by the +sum + + align:start position:0% +sum + + + align:start position:0% +sum +of two other rational numbers. + + align:start position:0% +of two other rational numbers. + + + align:start position:0% +of two other rational numbers. +Well, the way I do it having things like + + align:start position:0% +Well, the way I do it having things like + + + align:start position:0% +Well, the way I do it having things like +plus rat and star rat is I'd say oh yeah + + align:start position:0% +plus rat and star rat is I'd say oh yeah + + + align:start position:0% +plus rat and star rat is I'd say oh yeah +what that is is is just the uh the + + align:start position:0% +what that is is is just the uh the + + + align:start position:0% +what that is is is just the uh the +product that's star rat + + align:start position:0% +product that's star rat + + + align:start position:0% +product that's star rat +of + + align:start position:0% + + + + align:start position:0% + +the sum of x and y + + align:start position:0% +the sum of x and y + + + align:start position:0% +the sum of x and y +and the sum + + align:start position:0% +and the sum + + + align:start position:0% +and the sum +of s and t. + + align:start position:0% +of s and t. + + + align:start position:0% +of s and t. +So except for syntax, + + align:start position:0% +So except for syntax, + + + align:start position:0% +So except for syntax, +I get an expression that looks like the + + align:start position:0% +I get an expression that looks like the + + + align:start position:0% +I get an expression that looks like the +way I want to think about it + + align:start position:0% +way I want to think about it + + + align:start position:0% +way I want to think about it +mathematically. I want to say there's + + align:start position:0% +mathematically. I want to say there's + + + align:start position:0% +mathematically. I want to say there's +there are two numbers. There's a thing + + align:start position:0% +there are two numbers. There's a thing + + + align:start position:0% +there are two numbers. There's a thing +which is the sum of them + + align:start position:0% +which is the sum of them + + + align:start position:0% +which is the sum of them +and there's a thing which is the sum of + + align:start position:0% +and there's a thing which is the sum of + + + align:start position:0% +and there's a thing which is the sum of +these two. That's that's this + + align:start position:0% +these two. That's that's this + + + align:start position:0% +these two. That's that's this +and this. And then I multiply them. So I + + align:start position:0% +and this. And then I multiply them. So I + + + align:start position:0% +and this. And then I multiply them. So I +get an expression that matches this + + align:start position:0% +get an expression that matches this + + + align:start position:0% +get an expression that matches this +expression. If I did the other thing, if + + align:start position:0% +expression. If I did the other thing, if + + + align:start position:0% +expression. If I did the other thing, if +I said, well, the way I want to think + + align:start position:0% +I said, well, the way I want to think + + + align:start position:0% +I said, well, the way I want to think +about this is I type into my machine + + align:start position:0% +about this is I type into my machine + + + align:start position:0% +about this is I type into my machine +four numbers, which are the numerators + + align:start position:0% +four numbers, which are the numerators + + + align:start position:0% +four numbers, which are the numerators +and denominators of X and Y, and then + + align:start position:0% +and denominators of X and Y, and then + + + align:start position:0% +and denominators of X and Y, and then +four more numbers, which are the + + align:start position:0% +four more numbers, which are the + + + align:start position:0% +four more numbers, which are the +numerators and denominators of X, S, and + + align:start position:0% +numerators and denominators of X, S, and + + + align:start position:0% +numerators and denominators of X, S, and +T. And then what I'd be sitting with is, + + align:start position:0% +T. And then what I'd be sitting with is, + + + align:start position:0% +T. And then what I'd be sitting with is, +well, what would I do? I'd add these, + + align:start position:0% +well, what would I do? I'd add these, + + + align:start position:0% +well, what would I do? I'd add these, +and somehow I'd have to have two + + align:start position:0% +and somehow I'd have to have two + + + align:start position:0% +and somehow I'd have to have two +temporary variables, which are the + + align:start position:0% +temporary variables, which are the + + + align:start position:0% +temporary variables, which are the +numerators and denominators of this sum. + + align:start position:0% +numerators and denominators of this sum. + + + align:start position:0% +numerators and denominators of this sum. +And I'd go off and store them someplace. + + align:start position:0% +And I'd go off and store them someplace. + + + align:start position:0% +And I'd go off and store them someplace. +And then I'd go over here. I'd type in + + align:start position:0% +And then I'd go over here. I'd type in + + + align:start position:0% +And then I'd go over here. I'd type in +four more numbers. I get two more + + align:start position:0% +four more numbers. I get two more + + + align:start position:0% +four more numbers. I get two more +temporary variables which are the + + align:start position:0% +temporary variables which are the + + + align:start position:0% +temporary variables which are the +numerators and denominators of S&T and + + align:start position:0% +numerators and denominators of S&T and + + + align:start position:0% +numerators and denominators of S&T and +T. And then finally I put those together + + align:start position:0% +T. And then finally I put those together + + + align:start position:0% +T. And then finally I put those together +by multiplying them. + + align:start position:0% +by multiplying them. + + + align:start position:0% +by multiplying them. +You see what's what's starting to + + align:start position:0% +You see what's what's starting to + + + align:start position:0% +You see what's what's starting to +happen? There are all these temporary + + align:start position:0% +happen? There are all these temporary + + + align:start position:0% +happen? There are all these temporary +variables which are which are sort of + + align:start position:0% +variables which are which are sort of + + + align:start position:0% +variables which are which are sort of +the guts of the internals of these + + align:start position:0% +the guts of the internals of these + + + align:start position:0% +the guts of the internals of these +rational numbers that start hanging out + + align:start position:0% +rational numbers that start hanging out + + + align:start position:0% +rational numbers that start hanging out +all over the system. And of course, if I + + align:start position:0% +all over the system. And of course, if I + + + align:start position:0% +all over the system. And of course, if I +had more and more complicated + + align:start position:0% +had more and more complicated + + + align:start position:0% +had more and more complicated +expressions, there'd be more and more + + align:start position:0% +expressions, there'd be more and more + + + align:start position:0% +expressions, there'd be more and more +guts hanging out that confused my + + align:start position:0% +guts hanging out that confused my + + + align:start position:0% +guts hanging out that confused my +programming. + + align:start position:0% +programming. + + + align:start position:0% +programming. +And those of you who sort of programmed + + align:start position:0% +And those of you who sort of programmed + + + align:start position:0% +And those of you who sort of programmed +things like that where you're just uh + + align:start position:0% +things like that where you're just uh + + + align:start position:0% +things like that where you're just uh +adding numbers in assembly language, you + + align:start position:0% +adding numbers in assembly language, you + + + align:start position:0% +adding numbers in assembly language, you +sort of see you have to suddenly be + + align:start position:0% +sort of see you have to suddenly be + + + align:start position:0% +sort of see you have to suddenly be +concerned with these temporary + + align:start position:0% +concerned with these temporary + + + align:start position:0% +concerned with these temporary +variables. + + align:start position:0% +variables. + + + align:start position:0% +variables. +But more more importantly, they they're + + align:start position:0% +But more more importantly, they they're + + + align:start position:0% +But more more importantly, they they're +gonna not more importantly than + + align:start position:0% +gonna not more importantly than + + + align:start position:0% +gonna not more importantly than +confusing my programming, they're going + + align:start position:0% +confusing my programming, they're going + + + align:start position:0% +confusing my programming, they're going +to confuse my mind because the whole + + align:start position:0% +to confuse my mind because the whole + + + align:start position:0% +to confuse my mind because the whole +name of this game + + align:start position:0% +name of this game + + + align:start position:0% +name of this game +is that we'd like the programming + + align:start position:0% +is that we'd like the programming + + + align:start position:0% +is that we'd like the programming +language + + align:start position:0% +language + + + align:start position:0% +language +to express the concepts that we have in + + align:start position:0% +to express the concepts that we have in + + + align:start position:0% +to express the concepts that we have in +our heads like rational numbers are + + align:start position:0% +our heads like rational numbers are + + + align:start position:0% +our heads like rational numbers are +things that you can add and then take + + align:start position:0% +things that you can add and then take + + + align:start position:0% +things that you can add and then take +that result and multiply them. + + align:start position:0% +that result and multiply them. + + + align:start position:0% +that result and multiply them. +Okay, let's break for questions. + + align:start position:0% + + + + align:start position:0% + +Yeah, + + align:start position:0% +Yeah, + + + align:start position:0% +Yeah, +I don't quite see the need where we had + + align:start position:0% +I don't quite see the need where we had + + + align:start position:0% +I don't quite see the need where we had +make rat with a numerator and + + align:start position:0% +make rat with a numerator and + + + align:start position:0% +make rat with a numerator and +denominator. We had to have the + + align:start position:0% +denominator. We had to have the + + + align:start position:0% +denominator. We had to have the +numerator and denominator to passes + + align:start position:0% +numerator and denominator to passes + + + align:start position:0% +numerator and denominator to passes +parameters to create the cloud. That's + + align:start position:0% +parameters to create the cloud. That's + + + align:start position:0% +parameters to create the cloud. That's +right. And then we extracted to get back + + align:start position:0% +right. And then we extracted to get back + + + align:start position:0% +right. And then we extracted to get back +what we had to have originally. + + align:start position:0% +what we had to have originally. + + + align:start position:0% +what we had to have originally. +That's right. + + align:start position:0% +That's right. + + + align:start position:0% +That's right. +Right. So the question is I sort of have + + align:start position:0% +Right. So the question is I sort of have + + + align:start position:0% +Right. So the question is I sort of have +the numerator and denominator. Why am I + + align:start position:0% +the numerator and denominator. Why am I + + + align:start position:0% +the numerator and denominator. Why am I +why am I worrying about having the cloud + + align:start position:0% +why am I worrying about having the cloud + + + align:start position:0% +why am I worrying about having the cloud +given that I have to get the pieces out? + + align:start position:0% +given that I have to get the pieces out? + + + align:start position:0% +given that I have to get the pieces out? +That's sort of what I tried to say at + + align:start position:0% +That's sort of what I tried to say at + + + align:start position:0% +That's sort of what I tried to say at +the end, but let me let me try and say + + align:start position:0% +the end, but let me let me try and say + + + align:start position:0% +the end, but let me let me try and say +it again because that's really the + + align:start position:0% +it again because that's really the + + + align:start position:0% +it again because that's really the +crucial question. The point is I want to + + align:start position:0% +crucial question. The point is I want to + + + align:start position:0% +crucial question. The point is I want to +carry this numerator and denominator + + align:start position:0% +carry this numerator and denominator + + + align:start position:0% +carry this numerator and denominator +around + + align:start position:0% +around + + + align:start position:0% +around +together all the time. + + align:start position:0% +together all the time. + + + align:start position:0% +together all the time. +And it's almost as if I I want to know + + align:start position:0% +And it's almost as if I I want to know + + + align:start position:0% +And it's almost as if I I want to know +yeah there's a numerator and denominator + + align:start position:0% +yeah there's a numerator and denominator + + + align:start position:0% +yeah there's a numerator and denominator +in there but also I would like to to say + + align:start position:0% +in there but also I would like to to say + + + align:start position:0% +in there but also I would like to to say +fine but from another point of view + + align:start position:0% +fine but from another point of view + + + align:start position:0% +fine but from another point of view +that's x and I carry x around and I name + + align:start position:0% +that's x and I carry x around and I name + + + align:start position:0% +that's x and I carry x around and I name +it as x and I hold it and I can say + + align:start position:0% +it as x and I hold it and I can say + + + align:start position:0% +it as x and I hold it and I can say +things like the sum of x and y rather + + align:start position:0% +things like the sum of x and y rather + + + align:start position:0% +things like the sum of x and y rather +than just have see it's not so bad when + + align:start position:0% +than just have see it's not so bad when + + + align:start position:0% +than just have see it's not so bad when +I only think about x but if I have a + + align:start position:0% +I only think about x but if I have a + + + align:start position:0% +I only think about x but if I have a +system with 10 rational numbers suddenly + + align:start position:0% +system with 10 rational numbers suddenly + + + align:start position:0% +system with 10 rational numbers suddenly +I have 20 numerators and denominators + + align:start position:0% +I have 20 numerators and denominators + + + align:start position:0% +I have 20 numerators and denominators +which are not necessarily if I don't + + align:start position:0% +which are not necessarily if I don't + + + align:start position:0% +which are not necessarily if I don't +link them then It's just 20 arbitrary + + align:start position:0% +link them then It's just 20 arbitrary + + + align:start position:0% +link them then It's just 20 arbitrary +numbers that are not linked in any + + align:start position:0% +numbers that are not linked in any + + + align:start position:0% +numbers that are not linked in any +particular way. It's I mean it's a lot + + align:start position:0% +particular way. It's I mean it's a lot + + + align:start position:0% +particular way. It's I mean it's a lot +like saying well I have these + + align:start position:0% +like saying well I have these + + + align:start position:0% +like saying well I have these +instructions that are the body of the + + align:start position:0% +instructions that are the body of the + + + align:start position:0% +instructions that are the body of the +procedures. Why do I want to package + + align:start position:0% +procedures. Why do I want to package + + + align:start position:0% +procedures. Why do I want to package +them and say it's the procedure? It's + + align:start position:0% +them and say it's the procedure? It's + + + align:start position:0% +them and say it's the procedure? It's +exactly the same idea. Okay. + + align:start position:0% + + + + align:start position:0% + +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +with just stretch and get somebody to + + align:start position:0% +with just stretch and get somebody to + + + align:start position:0% +with just stretch and get somebody to +[Music] + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +Okay. Well, we've been working on this + + align:start position:0% +Okay. Well, we've been working on this + + + align:start position:0% +Okay. Well, we've been working on this +rational number arithmetic system. + + align:start position:0% +rational number arithmetic system. + + + align:start position:0% +rational number arithmetic system. +And then what we did, right, the + + align:start position:0% +And then what we did, right, the + + + align:start position:0% +And then what we did, right, the +important thing about what we did is we + + align:start position:0% +important thing about what we did is we + + + align:start position:0% +important thing about what we did is we +thought about the problem by breaking it + + align:start position:0% +thought about the problem by breaking it + + + align:start position:0% +thought about the problem by breaking it +into two pieces, + + align:start position:0% +into two pieces, + + + align:start position:0% +into two pieces, +right? We said assume there's this + + align:start position:0% +right? We said assume there's this + + + align:start position:0% +right? We said assume there's this +contract with George and George has + + align:start position:0% +contract with George and George has + + + align:start position:0% +contract with George and George has +figured out the way to how to construct + + align:start position:0% +figured out the way to how to construct + + + align:start position:0% +figured out the way to how to construct +these clouds + + align:start position:0% +these clouds + + + align:start position:0% +these clouds +provided us procedures make rat which + + align:start position:0% +provided us procedures make rat which + + + align:start position:0% +provided us procedures make rat which +was a constructor and selectors which + + align:start position:0% +was a constructor and selectors which + + + align:start position:0% +was a constructor and selectors which +are numer and denominator and then in + + align:start position:0% +are numer and denominator and then in + + + align:start position:0% +are numer and denominator and then in +terms of that we went off and + + align:start position:0% +terms of that we went off and + + + align:start position:0% +terms of that we went off and +implemented addition and multiplication + + align:start position:0% +implemented addition and multiplication + + + align:start position:0% +implemented addition and multiplication +of rational numbers. + + align:start position:0% +of rational numbers. + + + align:start position:0% +of rational numbers. +Well, now let's go look at George's + + align:start position:0% +Well, now let's go look at George's + + + align:start position:0% +Well, now let's go look at George's +problem, right? How can we go and + + align:start position:0% +problem, right? How can we go and + + + align:start position:0% +problem, right? How can we go and +package together a numerator and a and a + + align:start position:0% +package together a numerator and a and a + + + align:start position:0% +package together a numerator and a and a +denominator to actually make one of + + align:start position:0% +denominator to actually make one of + + + align:start position:0% +denominator to actually make one of +these clouds? See, what we need is a + + align:start position:0% +these clouds? See, what we need is a + + + align:start position:0% +these clouds? See, what we need is a +kind of glue + + align:start position:0% +kind of glue + + + align:start position:0% +kind of glue +kind of glue that a glue for data + + align:start position:0% +kind of glue that a glue for data + + + align:start position:0% +kind of glue that a glue for data +objects that allows us to put things + + align:start position:0% +objects that allows us to put things + + + align:start position:0% +objects that allows us to put things +together and uh list provides such a + + align:start position:0% +together and uh list provides such a + + + align:start position:0% +together and uh list provides such a +glue. + + align:start position:0% +glue. + + + align:start position:0% +glue. +That glue is is called list structure. + + align:start position:0% + + + + align:start position:0% + +that list structure is a way of gluing + + align:start position:0% +that list structure is a way of gluing + + + align:start position:0% +that list structure is a way of gluing +things together + + align:start position:0% +things together + + + align:start position:0% +things together +and more precisely list provides a way + + align:start position:0% +and more precisely list provides a way + + + align:start position:0% +and more precisely list provides a way +of constructing things called pairs. + + align:start position:0% + + + + align:start position:0% + +Okay, there's a there's a primitive + + align:start position:0% +Okay, there's a there's a primitive + + + align:start position:0% +Okay, there's a there's a primitive +operator in lisp called cons. + + align:start position:0% +operator in lisp called cons. + + + align:start position:0% +operator in lisp called cons. +You can take a look at it. + + align:start position:0% +You can take a look at it. + + + align:start position:0% +You can take a look at it. +There's a thing called called cons, + + align:start position:0% +There's a thing called called cons, + + + align:start position:0% +There's a thing called called cons, +right? Conce is an operator which takes + + align:start position:0% +right? Conce is an operator which takes + + + align:start position:0% +right? Conce is an operator which takes +in two arguments called x and y + + align:start position:0% +in two arguments called x and y + + + align:start position:0% +in two arguments called x and y +and it returns for us a thing called a + + align:start position:0% +and it returns for us a thing called a + + + align:start position:0% +and it returns for us a thing called a +pair, + + align:start position:0% +pair, + + + align:start position:0% +pair, +right? Things called it's a thing called + + align:start position:0% +right? Things called it's a thing called + + + align:start position:0% +right? Things called it's a thing called +a pair, + + align:start position:0% +a pair, + + + align:start position:0% +a pair, +right? That has a first part and a + + align:start position:0% +right? That has a first part and a + + + align:start position:0% +right? That has a first part and a +second part, + + align:start position:0% + + + + align:start position:0% + +right? So K takes two objects. + + align:start position:0% +right? So K takes two objects. + + + align:start position:0% +right? So K takes two objects. +There's a thing called a pair. The first + + align:start position:0% +There's a thing called a pair. The first + + + align:start position:0% +There's a thing called a pair. The first +part of the con is X and the second part + + align:start position:0% +part of the con is X and the second part + + + align:start position:0% +part of the con is X and the second part +of the con is Y. And that's what it + + align:start position:0% +of the con is Y. And that's what it + + + align:start position:0% +of the con is Y. And that's what it +builds. + + align:start position:0% +builds. + + + align:start position:0% +builds. +And then we also assume we have ways of + + align:start position:0% +And then we also assume we have ways of + + + align:start position:0% +And then we also assume we have ways of +getting things out. If you're given a + + align:start position:0% +getting things out. If you're given a + + + align:start position:0% +getting things out. If you're given a +pair, there's a thing called car. + + align:start position:0% +pair, there's a thing called car. + + + align:start position:0% +pair, there's a thing called car. +And car of a pair P gives you out the + + align:start position:0% +And car of a pair P gives you out the + + + align:start position:0% +And car of a pair P gives you out the +first part of the pair P. And there's a + + align:start position:0% +first part of the pair P. And there's a + + + align:start position:0% +first part of the pair P. And there's a +thing called cutter. the coder of the + + align:start position:0% +thing called cutter. the coder of the + + + align:start position:0% +thing called cutter. the coder of the +pair P gives you the the second part of + + align:start position:0% +pair P gives you the the second part of + + + align:start position:0% +pair P gives you the the second part of +the pair P. + + align:start position:0% +the pair P. + + + align:start position:0% +the pair P. +Okay, so that's how we construct things. + + align:start position:0% +Okay, so that's how we construct things. + + + align:start position:0% +Okay, so that's how we construct things. +There's also a uh conventional way of of + + align:start position:0% +There's also a uh conventional way of of + + + align:start position:0% +There's also a uh conventional way of of +drawing pictures of these things just + + align:start position:0% +drawing pictures of these things just + + + align:start position:0% +drawing pictures of these things just +like we write down uh + + align:start position:0% +like we write down uh + + + align:start position:0% +like we write down uh +just as we write down that as the + + align:start position:0% +just as we write down that as the + + + align:start position:0% +just as we write down that as the +conventional way of writing Plato's idea + + align:start position:0% +conventional way of writing Plato's idea + + + align:start position:0% +conventional way of writing Plato's idea +of two. + + align:start position:0% +of two. + + + align:start position:0% +of two. +The way we would we could + + align:start position:0% +The way we would we could + + + align:start position:0% +The way we would we could +draw a diagram to represent con of two + + align:start position:0% +draw a diagram to represent con of two + + + align:start position:0% +draw a diagram to represent con of two +and three is like this. We draw a little + + align:start position:0% +and three is like this. We draw a little + + + align:start position:0% +and three is like this. We draw a little +box + + align:start position:0% +box + + + align:start position:0% +box +and say here's the box we're talking + + align:start position:0% +and say here's the box we're talking + + + align:start position:0% +and say here's the box we're talking +about. And this box has two arrows + + align:start position:0% +about. And this box has two arrows + + + align:start position:0% +about. And this box has two arrows +coming out of it. + + align:start position:0% +coming out of it. + + + align:start position:0% +coming out of it. +Let's say the first + + align:start position:0% +Let's say the first + + + align:start position:0% +Let's say the first +part of this this pair is two. And the + + align:start position:0% +part of this this pair is two. And the + + + align:start position:0% +part of this this pair is two. And the +second part of this pair is three. + + align:start position:0% +second part of this pair is three. + + + align:start position:0% +second part of this pair is three. +And this notation has a name. It's + + align:start position:0% +And this notation has a name. It's + + + align:start position:0% +And this notation has a name. It's +called box. + + align:start position:0% +called box. + + + align:start position:0% +called box. +It's called box and pointer notation. + + align:start position:0% + + + + align:start position:0% + +Okay, by the way, let me say right now + + align:start position:0% +Okay, by the way, let me say right now + + + align:start position:0% +Okay, by the way, let me say right now +that a lot of people get confused that + + align:start position:0% +that a lot of people get confused that + + + align:start position:0% +that a lot of people get confused that +there's some significance to the + + align:start position:0% +there's some significance to the + + + align:start position:0% +there's some significance to the +geometric way I drew these pointers, the + + align:start position:0% +geometric way I drew these pointers, the + + + align:start position:0% +geometric way I drew these pointers, the +directions. Like some people think it'd + + align:start position:0% +directions. Like some people think it'd + + + align:start position:0% +directions. Like some people think it'd +be different if I took this pointer and + + align:start position:0% +be different if I took this pointer and + + + align:start position:0% +be different if I took this pointer and +turned it up here and put the three out + + align:start position:0% +turned it up here and put the three out + + + align:start position:0% +turned it up here and put the three out +here. That has no significance, right? + + align:start position:0% +here. That has no significance, right? + + + align:start position:0% +here. That has no significance, right? +It's it's merely you have a bunch of + + align:start position:0% +It's it's merely you have a bunch of + + + align:start position:0% +It's it's merely you have a bunch of +arrows, these pointers, right? and the + + align:start position:0% +arrows, these pointers, right? and the + + + align:start position:0% +arrows, these pointers, right? and the +boxes. And the only issue is the is how + + align:start position:0% +boxes. And the only issue is the is how + + + align:start position:0% +boxes. And the only issue is the is how +they're connected, not the the geometric + + align:start position:0% +they're connected, not the the geometric + + + align:start position:0% +they're connected, not the the geometric +arrangement of whether I write the + + align:start position:0% +arrangement of whether I write the + + + align:start position:0% +arrangement of whether I write the +pointer across or up or down. + + align:start position:0% +pointer across or up or down. + + + align:start position:0% +pointer across or up or down. +Now, it's completely unobvious + + align:start position:0% +Now, it's completely unobvious + + + align:start position:0% +Now, it's completely unobvious +probably why that's called list + + align:start position:0% +probably why that's called list + + + align:start position:0% +probably why that's called list +structure. We're not actually going to + + align:start position:0% +structure. We're not actually going to + + + align:start position:0% +structure. We're not actually going to +talk about that today. We'll we'll see + + align:start position:0% +talk about that today. We'll we'll see + + + align:start position:0% +talk about that today. We'll we'll see +that next time. + + align:start position:0% + + + + align:start position:0% + +Okay. So, those are pairs. There's K + + align:start position:0% +Okay. So, those are pairs. There's K + + + align:start position:0% +Okay. So, those are pairs. There's K +that constructs them. And what I'm going + + align:start position:0% +that constructs them. And what I'm going + + + align:start position:0% +that constructs them. And what I'm going +to know about Kant and K and Cutter is + + align:start position:0% +to know about Kant and K and Cutter is + + + align:start position:0% +to know about Kant and K and Cutter is +precisely that if I give if I have any X + + align:start position:0% +precisely that if I give if I have any X + + + align:start position:0% +precisely that if I give if I have any X +and Y right if I'm going to say if I + + align:start position:0% +and Y right if I'm going to say if I + + + align:start position:0% +and Y right if I'm going to say if I +have anything X and Y + + align:start position:0% +have anything X and Y + + + align:start position:0% +have anything X and Y +and I use cons to construct a pair + + align:start position:0% + + + + align:start position:0% + +then the car of that pair is going to be + + align:start position:0% +then the car of that pair is going to be + + + align:start position:0% +then the car of that pair is going to be +X the thing I put in and the critter of + + align:start position:0% +X the thing I put in and the critter of + + + align:start position:0% +X the thing I put in and the critter of +that pair is going to be Y + + align:start position:0% +that pair is going to be Y + + + align:start position:0% +that pair is going to be Y +right that's the that's the behavior of + + align:start position:0% +right that's the that's the behavior of + + + align:start position:0% +right that's the that's the behavior of +these operators const car and citter + + align:start position:0% +these operators const car and citter + + + align:start position:0% +these operators const car and citter +given them it's pretty clear how George + + align:start position:0% +given them it's pretty clear how George + + + align:start position:0% +given them it's pretty clear how George +can go off and construct his rational + + align:start position:0% +can go off and construct his rational + + + align:start position:0% +can go off and construct his rational +numbers + + align:start position:0% +numbers + + + align:start position:0% +numbers +after all he has to do remember George's + + align:start position:0% +after all he has to do remember George's + + + align:start position:0% +after all he has to do remember George's +problem was to implement make rat + + align:start position:0% +problem was to implement make rat + + + align:start position:0% +problem was to implement make rat +numerator and denom so all George has to + + align:start position:0% +numerator and denom so all George has to + + + align:start position:0% +numerator and denom so all George has to +do is say define + + align:start position:0% + + + + align:start position:0% + +make rat + + align:start position:0% + + + + align:start position:0% + +of some n and a g well all I have to do + + align:start position:0% +of some n and a g well all I have to do + + + align:start position:0% +of some n and a g well all I have to do +is constant + + align:start position:0% +is constant + + + align:start position:0% +is constant +That's constant of n to d + + align:start position:0% +That's constant of n to d + + + align:start position:0% +That's constant of n to d +and then if I want to get the numerator + + align:start position:0% +and then if I want to get the numerator + + + align:start position:0% +and then if I want to get the numerator +out I can say define + + align:start position:0% + + + + align:start position:0% + +the numerator numer + + align:start position:0% + + + + align:start position:0% + +of some rational number x. If the + + align:start position:0% +of some rational number x. If the + + + align:start position:0% +of some rational number x. If the +rational number is implemented as a pair + + align:start position:0% +rational number is implemented as a pair + + + align:start position:0% +rational number is implemented as a pair +then all I have to do is get out the car + + align:start position:0% +then all I have to do is get out the car + + + align:start position:0% +then all I have to do is get out the car +of x + + align:start position:0% +of x + + + align:start position:0% +of x +and then similarly + + align:start position:0% +and then similarly + + + align:start position:0% +and then similarly +define + + align:start position:0% + + + + align:start position:0% + +the denom + + align:start position:0% + + + + align:start position:0% + +is going to be the critter the other + + align:start position:0% +is going to be the critter the other + + + align:start position:0% +is going to be the critter the other +thing I put into the pair. + + align:start position:0% + + + + align:start position:0% + +Well, now we're in business, right? + + align:start position:0% +Well, now we're in business, right? + + + align:start position:0% +Well, now we're in business, right? +That's the + + align:start position:0% +That's the + + + align:start position:0% +That's the +that's a complete implementation of + + align:start position:0% +that's a complete implementation of + + + align:start position:0% +that's a complete implementation of +rational numbers. Let's use it. Suppose + + align:start position:0% +rational numbers. Let's use it. Suppose + + + align:start position:0% +rational numbers. Let's use it. Suppose +I want to say so I want to think about + + align:start position:0% +I want to say so I want to think about + + + align:start position:0% +I want to say so I want to think about +how to add 1/2 + 1/4 + + align:start position:0% +how to add 1/2 + 1/4 + + + align:start position:0% +how to add 1/2 + 1/4 +and see watch the system work. Well, the + + align:start position:0% +and see watch the system work. Well, the + + + align:start position:0% +and see watch the system work. Well, the +way I'd use that is I'd say well maybe + + align:start position:0% +way I'd use that is I'd say well maybe + + + align:start position:0% +way I'd use that is I'd say well maybe +define + + align:start position:0% + + + + align:start position:0% + +define a I have to make a 1/2. + + align:start position:0% +define a I have to make a 1/2. + + + align:start position:0% +define a I have to make a 1/2. +Well, that's a rational number with + + align:start position:0% +Well, that's a rational number with + + + align:start position:0% +Well, that's a rational number with +numerator one and denominator two. + + align:start position:0% +numerator one and denominator two. + + + align:start position:0% +numerator one and denominator two. +So a will be make rat of one and two + + align:start position:0% + + + + align:start position:0% + +and then I'll construct the 1/4. I'll + + align:start position:0% +and then I'll construct the 1/4. I'll + + + align:start position:0% +and then I'll construct the 1/4. I'll +say define + + align:start position:0% +say define + + + align:start position:0% +say define +d + + align:start position:0% +d + + + align:start position:0% +d +to be + + align:start position:0% +to be + + + align:start position:0% +to be +make rat + + align:start position:0% +make rat + + + align:start position:0% +make rat +of uh + + align:start position:0% +of uh + + + align:start position:0% +of uh +1 and four. + + align:start position:0% + + + + align:start position:0% + +And if I'd like to look at the answer, + + align:start position:0% +And if I'd like to look at the answer, + + + align:start position:0% +And if I'd like to look at the answer, +well, assuming I don't have a special + + align:start position:0% +well, assuming I don't have a special + + + align:start position:0% +well, assuming I don't have a special +thing that prints rational numbers or I + + align:start position:0% +thing that prints rational numbers or I + + + align:start position:0% +thing that prints rational numbers or I +could make one, I could say, for + + align:start position:0% +could make one, I could say, for + + + align:start position:0% +could make one, I could say, for +instance, define + + align:start position:0% + + + + align:start position:0% + +the answer + + align:start position:0% + + + + align:start position:0% + +to be plus rat + + align:start position:0% +to be plus rat + + + align:start position:0% +to be plus rat +of a and b. + + align:start position:0% +of a and b. + + + align:start position:0% +of a and b. +And now I can say what's the answer? + + align:start position:0% +And now I can say what's the answer? + + + align:start position:0% +And now I can say what's the answer? +What's the what are the numerators and + + align:start position:0% +What's the what are the numerators and + + + align:start position:0% +What's the what are the numerators and +denominators of the answer? So if I'm + + align:start position:0% +denominators of the answer? So if I'm + + + align:start position:0% +denominators of the answer? So if I'm +adding 1/2 and 1/4, + + align:start position:0% +adding 1/2 and 1/4, + + + align:start position:0% +adding 1/2 and 1/4, +I'll say what is the numerator + + align:start position:0% + + + + align:start position:0% + +of the answer + + align:start position:0% + + + + align:start position:0% + +and the system is going to type out + + align:start position:0% + + + + align:start position:0% + +well six. Bad news. + + align:start position:0% +well six. Bad news. + + + align:start position:0% +well six. Bad news. +And if I say what's the denominator of + + align:start position:0% +And if I say what's the denominator of + + + align:start position:0% +And if I say what's the denominator of +the answer, + + align:start position:0% + + + + align:start position:0% + +the system's going to type out eight. + + align:start position:0% +the system's going to type out eight. + + + align:start position:0% +the system's going to type out eight. +So instead of what I would really like, + + align:start position:0% +So instead of what I would really like, + + + align:start position:0% +So instead of what I would really like, +which is for it to say that 1/2 and 1/4 + + align:start position:0% +which is for it to say that 1/2 and 1/4 + + + align:start position:0% +which is for it to say that 1/2 and 1/4 +is 3/4s, + + align:start position:0% + + + + align:start position:0% + +this foolish machine is going to say, + + align:start position:0% +this foolish machine is going to say, + + + align:start position:0% +this foolish machine is going to say, +"No, it's 68." + + align:start position:0% +"No, it's 68." + + + align:start position:0% +"No, it's 68." +You know, that's that's sort of bad + + align:start position:0% +You know, that's that's sort of bad + + + align:start position:0% +You know, that's that's sort of bad +news. + + align:start position:0% +news. + + + align:start position:0% +news. +Where's the bug? + + align:start position:0% + + + + align:start position:0% + +Why does it do that after all? Well, + + align:start position:0% +Why does it do that after all? Well, + + + align:start position:0% +Why does it do that after all? Well, +it's the way that we just had plus rat. + + align:start position:0% +it's the way that we just had plus rat. + + + align:start position:0% +it's the way that we just had plus rat. +Plus rat just took the right. It said + + align:start position:0% +Plus rat just took the right. It said + + + align:start position:0% +Plus rat just took the right. It said +you add the the numerator times the + + align:start position:0% +you add the the numerator times the + + + align:start position:0% +you add the the numerator times the +denominator. + + align:start position:0% +denominator. + + + align:start position:0% +denominator. +You add that to the numerator times the + + align:start position:0% +You add that to the numerator times the + + + align:start position:0% +You add that to the numerator times the +denominator and put that over the + + align:start position:0% +denominator and put that over the + + + align:start position:0% +denominator and put that over the +product of the two denominators and + + align:start position:0% +product of the two denominators and + + + align:start position:0% +product of the two denominators and +that's why you get 68. + + align:start position:0% +that's why you get 68. + + + align:start position:0% +that's why you get 68. +So what was wrong with our + + align:start position:0% +So what was wrong with our + + + align:start position:0% +So what was wrong with our +implementation of plus rad? What's wrong + + align:start position:0% +implementation of plus rad? What's wrong + + + align:start position:0% +implementation of plus rad? What's wrong +with that rational number arithmetic + + align:start position:0% +with that rational number arithmetic + + + align:start position:0% +with that rational number arithmetic +stuff that we did before the break? + + align:start position:0% +stuff that we did before the break? + + + align:start position:0% +stuff that we did before the break? +Well, the answer is one way to look at + + align:start position:0% +Well, the answer is one way to look at + + + align:start position:0% +Well, the answer is one way to look at +it is absolutely nothing's wrong with + + align:start position:0% +it is absolutely nothing's wrong with + + + align:start position:0% +it is absolutely nothing's wrong with +it. That's perfectly good + + align:start position:0% +it. That's perfectly good + + + align:start position:0% +it. That's perfectly good +implementation. Follows the right + + align:start position:0% +implementation. Follows the right + + + align:start position:0% +implementation. Follows the right +follows the the sixth grade, fifth grade + + align:start position:0% +follows the the sixth grade, fifth grade + + + align:start position:0% +follows the the sixth grade, fifth grade +mathematics for adding fractions. + + align:start position:0% + + + + align:start position:0% + +One thing we can say is, well, that's + + align:start position:0% +One thing we can say is, well, that's + + + align:start position:0% +One thing we can say is, well, that's +George's problem, right? Boy, wasn't + + align:start position:0% +George's problem, right? Boy, wasn't + + + align:start position:0% +George's problem, right? Boy, wasn't +George dumb to say that he can make a + + align:start position:0% +George dumb to say that he can make a + + + align:start position:0% +George dumb to say that he can make a +rational number simply by sticking + + align:start position:0% +rational number simply by sticking + + + align:start position:0% +rational number simply by sticking +together the numerator and denominator, + + align:start position:0% +together the numerator and denominator, + + + align:start position:0% +together the numerator and denominator, +right? Wouldn't it be better for George + + align:start position:0% +right? Wouldn't it be better for George + + + align:start position:0% +right? Wouldn't it be better for George +when he made a rational number to reduce + + align:start position:0% +when he made a rational number to reduce + + + align:start position:0% +when he made a rational number to reduce +the stuff to lowest terms? + + align:start position:0% +the stuff to lowest terms? + + + align:start position:0% +the stuff to lowest terms? +And what I mean is, wouldn't it be + + align:start position:0% +And what I mean is, wouldn't it be + + + align:start position:0% +And what I mean is, wouldn't it be +better + + align:start position:0% +better + + + align:start position:0% +better +for George instead of using this version + + align:start position:0% +for George instead of using this version + + + align:start position:0% +for George instead of using this version +of Maker + + align:start position:0% +of Maker + + + align:start position:0% +of Maker +to use this one on the slide + + align:start position:0% +to use this one on the slide + + + align:start position:0% +to use this one on the slide +where instead of just saying const + + align:start position:0% +where instead of just saying const + + + align:start position:0% +where instead of just saying const +together N and D, what you do is compute + + align:start position:0% +together N and D, what you do is compute + + + align:start position:0% +together N and D, what you do is compute +the greatest common divisor of N and D + + align:start position:0% +the greatest common divisor of N and D + + + align:start position:0% +the greatest common divisor of N and D +and GCD is a procedure which well for + + align:start position:0% +and GCD is a procedure which well for + + + align:start position:0% +and GCD is a procedure which well for +all we care is a primitive which + + align:start position:0% +all we care is a primitive which + + + align:start position:0% +all we care is a primitive which +computes the greatest common divisor of + + align:start position:0% +computes the greatest common divisor of + + + align:start position:0% +computes the greatest common divisor of +two numbers. + + align:start position:0% +two numbers. + + + align:start position:0% +two numbers. +So the way I can construct a rational + + align:start position:0% +So the way I can construct a rational + + + align:start position:0% +So the way I can construct a rational +number is + + align:start position:0% +number is + + + align:start position:0% +number is +get the greatest common divisor of the + + align:start position:0% +get the greatest common divisor of the + + + align:start position:0% +get the greatest common divisor of the +two numbers and I'm going to call that + + align:start position:0% +two numbers and I'm going to call that + + + align:start position:0% +two numbers and I'm going to call that +G. + + align:start position:0% +G. + + + align:start position:0% +G. +And then instead of constanting together + + align:start position:0% +And then instead of constanting together + + + align:start position:0% +And then instead of constanting together +N and D, I'll divide them through. I'll + + align:start position:0% +N and D, I'll divide them through. I'll + + + align:start position:0% +N and D, I'll divide them through. I'll +constant together the quotient of the N + + align:start position:0% +constant together the quotient of the N + + + align:start position:0% +constant together the quotient of the N +by the the GCD and the quotient of D by + + align:start position:0% +by the the GCD and the quotient of D by + + + align:start position:0% +by the the GCD and the quotient of D by +the GCD + + align:start position:0% +the GCD + + + align:start position:0% +the GCD +and that'll reduce a rational number to + + align:start position:0% +and that'll reduce a rational number to + + + align:start position:0% +and that'll reduce a rational number to +lowest terms. + + align:start position:0% +lowest terms. + + + align:start position:0% +lowest terms. +So that when + + align:start position:0% + + + + align:start position:0% + +right so when I do this addition when + + align:start position:0% +right so when I do this addition when + + + align:start position:0% +right so when I do this addition when +this when plus rat calls + + align:start position:0% +this when plus rat calls + + + align:start position:0% +this when plus rat calls +nrat remember the definition of plus rat + + align:start position:0% +nrat remember the definition of plus rat + + + align:start position:0% +nrat remember the definition of plus rat +it have a nrat in there just by the fact + + align:start position:0% +it have a nrat in there just by the fact + + + align:start position:0% +it have a nrat in there just by the fact +that it's constructing that the thing + + align:start position:0% +that it's constructing that the thing + + + align:start position:0% +that it's constructing that the thing +will get reduced to lowest terms + + align:start position:0% +will get reduced to lowest terms + + + align:start position:0% +will get reduced to lowest terms +automatically + + align:start position:0% + + + + align:start position:0% + +okay that + + align:start position:0% +okay that + + + align:start position:0% +okay that +that is a complete system, + + align:start position:0% +that is a complete system, + + + align:start position:0% +that is a complete system, +right? For rational number arithmetic. + + align:start position:0% +right? For rational number arithmetic. + + + align:start position:0% +right? For rational number arithmetic. +Let's look at what we've done, + + align:start position:0% +Let's look at what we've done, + + + align:start position:0% +Let's look at what we've done, +right? We said we want to build rational + + align:start position:0% +right? We said we want to build rational + + + align:start position:0% +right? We said we want to build rational +number arithmetic + + align:start position:0% + + + + align:start position:0% + +and we had a thing called plus rat. We + + align:start position:0% +and we had a thing called plus rat. We + + + align:start position:0% +and we had a thing called plus rat. We +implemented that + + align:start position:0% +implemented that + + + align:start position:0% +implemented that +and uh showed you multiplying rational + + align:start position:0% +and uh showed you multiplying rational + + + align:start position:0% +and uh showed you multiplying rational +numbers and although I didn't put them + + align:start position:0% +numbers and although I didn't put them + + + align:start position:0% +numbers and although I didn't put them +up there presumably we'd like to have + + align:start position:0% +up there presumably we'd like to have + + + align:start position:0% +up there presumably we'd like to have +something that subtracts rational + + align:start position:0% +something that subtracts rational + + + align:start position:0% +something that subtracts rational +numbers and I don't know all sorts of + + align:start position:0% +numbers and I don't know all sorts of + + + align:start position:0% +numbers and I don't know all sorts of +things things that test equality and + + align:start position:0% +things things that test equality and + + + align:start position:0% +things things that test equality and +division and maybe things that print + + align:start position:0% +division and maybe things that print + + + align:start position:0% +division and maybe things that print +rational numbers in some particular way + + align:start position:0% +rational numbers in some particular way + + + align:start position:0% +rational numbers in some particular way +and we implemented those + + align:start position:0% +and we implemented those + + + align:start position:0% +and we implemented those +in terms of pairs + + align:start position:0% +in terms of pairs + + + align:start position:0% +in terms of pairs +these pairs conar and critter that are + + align:start position:0% +these pairs conar and critter that are + + + align:start position:0% +these pairs conar and critter that are +built into lisp but the important thing + + align:start position:0% +built into lisp but the important thing + + + align:start position:0% +built into lisp but the important thing +is that between + + align:start position:0% +is that between + + + align:start position:0% +is that between +these + + align:start position:0% +these + + + align:start position:0% +these +and these we set up an abstraction + + align:start position:0% +and these we set up an abstraction + + + align:start position:0% +and these we set up an abstraction +barrier. We set up a layer of + + align:start position:0% +barrier. We set up a layer of + + + align:start position:0% +barrier. We set up a layer of +abstraction. + + align:start position:0% + + + + align:start position:0% + +And what was that layer of abstraction? + + align:start position:0% +And what was that layer of abstraction? + + + align:start position:0% +And what was that layer of abstraction? +That layer abstraction was precisely the + + align:start position:0% +That layer abstraction was precisely the + + + align:start position:0% +That layer abstraction was precisely the +constructor and the selectors. + + align:start position:0% + + + + align:start position:0% + +This layer was mrat + + align:start position:0% +This layer was mrat + + + align:start position:0% +This layer was mrat +and numer + + align:start position:0% + + + + align:start position:0% + +and denom + + align:start position:0% + + + + align:start position:0% + +this methodology + + align:start position:0% +this methodology + + + align:start position:0% +this methodology +right this methodology another way to + + align:start position:0% +right this methodology another way to + + + align:start position:0% +right this methodology another way to +say what it's doing is that we are + + align:start position:0% +say what it's doing is that we are + + + align:start position:0% +say what it's doing is that we are +separating + + align:start position:0% + + + + align:start position:0% + +we're separating the way something is + + align:start position:0% +we're separating the way something is + + + align:start position:0% +we're separating the way something is +used + + align:start position:0% +used + + + align:start position:0% +used +separating the use of data object + + align:start position:0% +separating the use of data object + + + align:start position:0% +separating the use of data object +objects from the representation of data + + align:start position:0% +objects from the representation of data + + + align:start position:0% +objects from the representation of data +objects. + + align:start position:0% + + + + align:start position:0% + +Right? So up here we have the way that + + align:start position:0% +Right? So up here we have the way that + + + align:start position:0% +Right? So up here we have the way that +rational numbers are used do arithmetic + + align:start position:0% +rational numbers are used do arithmetic + + + align:start position:0% +rational numbers are used do arithmetic +on them. Down here we have the way that + + align:start position:0% +on them. Down here we have the way that + + + align:start position:0% +on them. Down here we have the way that +they're represented and they're + + align:start position:0% +they're represented and they're + + + align:start position:0% +they're represented and they're +separated by this boundary. The boundary + + align:start position:0% +separated by this boundary. The boundary + + + align:start position:0% +separated by this boundary. The boundary +is the constructors and selectors. + + align:start position:0% + + + + align:start position:0% + +Okay. And this this methodology has a + + align:start position:0% +Okay. And this this methodology has a + + + align:start position:0% +Okay. And this this methodology has a +name. This is called data abstraction. + + align:start position:0% + + + + align:start position:0% + +Data abstraction is sort of the + + align:start position:0% +Data abstraction is sort of the + + + align:start position:0% +Data abstraction is sort of the +programming methodology of setting up + + align:start position:0% +programming methodology of setting up + + + align:start position:0% +programming methodology of setting up +data objects by postulating constructors + + align:start position:0% +data objects by postulating constructors + + + align:start position:0% +data objects by postulating constructors +and selectors to isolate use from + + align:start position:0% +and selectors to isolate use from + + + align:start position:0% +and selectors to isolate use from +representation. + + align:start position:0% + + + + align:start position:0% + +Well, so what? I mean, after all, we + + align:start position:0% +Well, so what? I mean, after all, we + + + align:start position:0% +Well, so what? I mean, after all, we +didn't have to do it this way. It's + + align:start position:0% +didn't have to do it this way. It's + + + align:start position:0% +didn't have to do it this way. It's +perfectly possible to do rational number + + align:start position:0% +perfectly possible to do rational number + + + align:start position:0% +perfectly possible to do rational number +addition without having any compound + + align:start position:0% +addition without having any compound + + + align:start position:0% +addition without having any compound +data objects. And here on this slide is + + align:start position:0% +data objects. And here on this slide is + + + align:start position:0% +data objects. And here on this slide is +one example. We certainly could have + + align:start position:0% +one example. We certainly could have + + + align:start position:0% +one example. We certainly could have +defined plus rat which takes in + + align:start position:0% +defined plus rat which takes in + + + align:start position:0% +defined plus rat which takes in +things x and y. And we'll say well what + + align:start position:0% +things x and y. And we'll say well what + + + align:start position:0% +things x and y. And we'll say well what +are these rational numbers really? + + align:start position:0% +are these rational numbers really? + + + align:start position:0% +are these rational numbers really? +Right? We'll say well really they're + + align:start position:0% +Right? We'll say well really they're + + + align:start position:0% +Right? We'll say well really they're +just pairs and the numerator is the car + + align:start position:0% +just pairs and the numerator is the car + + + align:start position:0% +just pairs and the numerator is the car +and the denominator is the cutter. So + + align:start position:0% +and the denominator is the cutter. So + + + align:start position:0% +and the denominator is the cutter. So +what we'll do is we'll take the car of X + + align:start position:0% +what we'll do is we'll take the car of X + + + align:start position:0% +what we'll do is we'll take the car of X +times the cooter of Y, + + align:start position:0% + + + + align:start position:0% + +multiply them. Take the car of Y times + + align:start position:0% +multiply them. Take the car of Y times + + + align:start position:0% +multiply them. Take the car of Y times +the coder of X, multiply them, add them. + + align:start position:0% +the coder of X, multiply them, add them. + + + align:start position:0% +the coder of X, multiply them, add them. +Take the cooter of X and the CER of Y, + + align:start position:0% +Take the cooter of X and the CER of Y, + + + align:start position:0% +Take the cooter of X and the CER of Y, +multiply them, and then const the two + + align:start position:0% +multiply them, and then const the two + + + align:start position:0% +multiply them, and then const the two +together. + + align:start position:0% +together. + + + align:start position:0% +together. +And that well that sort of does the same + + align:start position:0% +And that well that sort of does the same + + + align:start position:0% +And that well that sort of does the same +thing, + + align:start position:0% +thing, + + + align:start position:0% +thing, +right? + + align:start position:0% +right? + + + align:start position:0% +right? +This ignores the problem of reducing + + align:start position:0% +This ignores the problem of reducing + + + align:start position:0% +This ignores the problem of reducing +things to lowest terms. But let's let's + + align:start position:0% +things to lowest terms. But let's let's + + + align:start position:0% +things to lowest terms. But let's let's +not worry about that for a minute. Well, + + align:start position:0% +not worry about that for a minute. Well, + + + align:start position:0% +not worry about that for a minute. Well, +so what why don't we do it that way? + + align:start position:0% +so what why don't we do it that way? + + + align:start position:0% +so what why don't we do it that way? +Right? After all, there there sort of + + align:start position:0% +Right? After all, there there sort of + + + align:start position:0% +Right? After all, there there sort of +fewer procedures to define and it's a + + align:start position:0% +fewer procedures to define and it's a + + + align:start position:0% +fewer procedures to define and it's a +lot more straightforward. + + align:start position:0% +lot more straightforward. + + + align:start position:0% +lot more straightforward. +Uh + + align:start position:0% +Uh + + + align:start position:0% +Uh +saves all this self-righteous BS about + + align:start position:0% +saves all this self-righteous BS about + + + align:start position:0% +saves all this self-righteous BS about +talking about data abstraction. We just + + align:start position:0% +talking about data abstraction. We just + + + align:start position:0% +talking about data abstraction. We just +sort of do it. I mean, who knows? Maybe + + align:start position:0% +sort of do it. I mean, who knows? Maybe + + + align:start position:0% +sort of do it. I mean, who knows? Maybe +it's even marginally more efficient + + align:start position:0% +it's even marginally more efficient + + + align:start position:0% +it's even marginally more efficient +depending on whatever compiler we're + + align:start position:0% +depending on whatever compiler we're + + + align:start position:0% +depending on whatever compiler we're +using for this, right? What's the what's + + align:start position:0% +using for this, right? What's the what's + + + align:start position:0% +using for this, right? What's the what's +the point of isolating the youth from + + align:start position:0% +the point of isolating the youth from + + + align:start position:0% +the point of isolating the youth from +the representation? + + align:start position:0% +the representation? + + + align:start position:0% +the representation? +Well, goes back to this notion of + + align:start position:0% +Well, goes back to this notion of + + + align:start position:0% +Well, goes back to this notion of +naming. Remember the one of the most + + align:start position:0% +naming. Remember the one of the most + + + align:start position:0% +naming. Remember the one of the most +important principles in programming is + + align:start position:0% +important principles in programming is + + + align:start position:0% +important principles in programming is +the same as one of the most important + + align:start position:0% +the same as one of the most important + + + align:start position:0% +the same as one of the most important +principles in sorcery, right? That's if + + align:start position:0% +principles in sorcery, right? That's if + + + align:start position:0% +principles in sorcery, right? That's if +you have the name of a spirit, you get + + align:start position:0% +you have the name of a spirit, you get + + + align:start position:0% +you have the name of a spirit, you get +control over it. And if you go back and + + align:start position:0% +control over it. And if you go back and + + + align:start position:0% +control over it. And if you go back and +look at this slide, + + align:start position:0% +look at this slide, + + + align:start position:0% +look at this slide, +you see what's in there is we have this + + align:start position:0% +you see what's in there is we have this + + + align:start position:0% +you see what's in there is we have this +thing plus rat, but nowhere in this + + align:start position:0% +thing plus rat, but nowhere in this + + + align:start position:0% +thing plus rat, but nowhere in this +system, if I have a plus rat and a minus + + align:start position:0% +system, if I have a plus rat and a minus + + + align:start position:0% +system, if I have a plus rat and a minus +rat and a star rat and things that look + + align:start position:0% +rat and a star rat and things that look + + + align:start position:0% +rat and a star rat and things that look +like that, nowhere in this system do I + + align:start position:0% +like that, nowhere in this system do I + + + align:start position:0% +like that, nowhere in this system do I +have a thing that I can point at + + align:start position:0% +have a thing that I can point at + + + align:start position:0% +have a thing that I can point at +thing that I can point at which is a + + align:start position:0% +thing that I can point at which is a + + + align:start position:0% +thing that I can point at which is a +rational number. + + align:start position:0% +rational number. + + + align:start position:0% +rational number. +Right? I don't have in a system like + + align:start position:0% +Right? I don't have in a system like + + + align:start position:0% +Right? I don't have in a system like +that the no idea of rational number as a + + align:start position:0% +that the no idea of rational number as a + + + align:start position:0% +that the no idea of rational number as a +conceptual entity. + + align:start position:0% +conceptual entity. + + + align:start position:0% +conceptual entity. +Well, what's the advantage of that? + + align:start position:0% +Well, what's the advantage of that? + + + align:start position:0% +Well, what's the advantage of that? +What's the advantage of of isolating the + + align:start position:0% +What's the advantage of of isolating the + + + align:start position:0% +What's the advantage of of isolating the +idea of rational number as a conceptual + + align:start position:0% +idea of rational number as a conceptual + + + align:start position:0% +idea of rational number as a conceptual +entity and really naming it with mrat + + align:start position:0% +entity and really naming it with mrat + + + align:start position:0% +entity and really naming it with mrat +numerator and denominator? + + align:start position:0% +numerator and denominator? + + + align:start position:0% +numerator and denominator? +Well, one advantage is you might want to + + align:start position:0% +Well, one advantage is you might want to + + + align:start position:0% +Well, one advantage is you might want to +you might want to have alternative + + align:start position:0% +you might want to have alternative + + + align:start position:0% +you might want to have alternative +representations. + + align:start position:0% +representations. + + + align:start position:0% +representations. +See before I showed you that one way + + align:start position:0% +See before I showed you that one way + + + align:start position:0% +See before I showed you that one way +George could solve this this uh things + + align:start position:0% +George could solve this this uh things + + + align:start position:0% +George could solve this this uh things +not reduced to lowered terms problem is + + align:start position:0% +not reduced to lowered terms problem is + + + align:start position:0% +not reduced to lowered terms problem is +when you build a rational number you + + align:start position:0% +when you build a rational number you + + + align:start position:0% +when you build a rational number you +divide out by the greatest common + + align:start position:0% +divide out by the greatest common + + + align:start position:0% +divide out by the greatest common +denominator. Another way to do that + + align:start position:0% +denominator. Another way to do that + + + align:start position:0% +denominator. Another way to do that +is uh shown over here I can have an + + align:start position:0% +is uh shown over here I can have an + + + align:start position:0% +is uh shown over here I can have an +alternative representation for rational + + align:start position:0% +alternative representation for rational + + + align:start position:0% +alternative representation for rational +numbers where when you make a rational + + align:start position:0% +numbers where when you make a rational + + + align:start position:0% +numbers where when you make a rational +number you just const them. + + align:start position:0% +number you just const them. + + + align:start position:0% +number you just const them. +However, when you go to select out the + + align:start position:0% +However, when you go to select out the + + + align:start position:0% +However, when you go to select out the +numerator at that point, you compute the + + align:start position:0% +numerator at that point, you compute the + + + align:start position:0% +numerator at that point, you compute the +GCD of the stuff that's sitting in that + + align:start position:0% +GCD of the stuff that's sitting in that + + + align:start position:0% +GCD of the stuff that's sitting in that +pair and divide out by the GCD. + + align:start position:0% + + + + align:start position:0% + +Right? And similarly, when I get the + + align:start position:0% +Right? And similarly, when I get the + + + align:start position:0% +Right? And similarly, when I get the +denominator + + align:start position:0% +denominator + + + align:start position:0% +denominator +at that point when I go to get the + + align:start position:0% +at that point when I go to get the + + + align:start position:0% +at that point when I go to get the +denominator, I'll divide out by the GCD. + + align:start position:0% +denominator, I'll divide out by the GCD. + + + align:start position:0% +denominator, I'll divide out by the GCD. +So, the difference would be in the old + + align:start position:0% +So, the difference would be in the old + + + align:start position:0% +So, the difference would be in the old +representation + + align:start position:0% +representation + + + align:start position:0% +representation +when ants was constructed here say with + + align:start position:0% +when ants was constructed here say with + + + align:start position:0% +when ants was constructed here say with +six and eight In the first way, the six + + align:start position:0% +six and eight In the first way, the six + + + align:start position:0% +six and eight In the first way, the six +and eight would have got reduced when + + align:start position:0% +and eight would have got reduced when + + + align:start position:0% +and eight would have got reduced when +they got stuck into that pair and + + align:start position:0% +they got stuck into that pair and + + + align:start position:0% +they got stuck into that pair and +numerator would select out three. + + align:start position:0% +numerator would select out three. + + + align:start position:0% +numerator would select out three. +And in the way I just showed you, well, + + align:start position:0% +And in the way I just showed you, well, + + + align:start position:0% +And in the way I just showed you, well, +ants would get six and eight put in. And + + align:start position:0% +ants would get six and eight put in. And + + + align:start position:0% +ants would get six and eight put in. And +then at the point where I said + + align:start position:0% +then at the point where I said + + + align:start position:0% +then at the point where I said +numerator, some computation would get + + align:start position:0% +numerator, some computation would get + + + align:start position:0% +numerator, some computation would get +done to put out three instead of six. + + align:start position:0% +done to put out three instead of six. + + + align:start position:0% +done to put out three instead of six. +So those are two different ways I might + + align:start position:0% +So those are two different ways I might + + + align:start position:0% +So those are two different ways I might +do it. Which one's better? + + align:start position:0% +do it. Which one's better? + + + align:start position:0% +do it. Which one's better? +Well, it depends, right? If I'm making a + + align:start position:0% +Well, it depends, right? If I'm making a + + + align:start position:0% +Well, it depends, right? If I'm making a +system where I am mostly constructing + + align:start position:0% +system where I am mostly constructing + + + align:start position:0% +system where I am mostly constructing +rational numbers and hardly ever looking + + align:start position:0% +rational numbers and hardly ever looking + + + align:start position:0% +rational numbers and hardly ever looking +at them, then it's probably better not + + align:start position:0% +at them, then it's probably better not + + + align:start position:0% +at them, then it's probably better not +to do that that GCD computation when I + + align:start position:0% +to do that that GCD computation when I + + + align:start position:0% +to do that that GCD computation when I +construct them. If I'm doing a system + + align:start position:0% +construct them. If I'm doing a system + + + align:start position:0% +construct them. If I'm doing a system +where I look at a look at things a lot + + align:start position:0% +where I look at a look at things a lot + + + align:start position:0% +where I look at a look at things a lot +more than I construct them, then it's + + align:start position:0% +more than I construct them, then it's + + + align:start position:0% +more than I construct them, then it's +probably better to to do the work when I + + align:start position:0% +probably better to to do the work when I + + + align:start position:0% +probably better to to do the work when I +construct them. + + align:start position:0% +construct them. + + + align:start position:0% +construct them. +So there's there's a choice there. But + + align:start position:0% +So there's there's a choice there. But + + + align:start position:0% +So there's there's a choice there. But +the real issue is that you might not be + + align:start position:0% +the real issue is that you might not be + + + align:start position:0% +the real issue is that you might not be +able to decide + + align:start position:0% +able to decide + + + align:start position:0% +able to decide +at the moment you're worrying about + + align:start position:0% +at the moment you're worrying about + + + align:start position:0% +at the moment you're worrying about +these rational numbers. See, in general, + + align:start position:0% +these rational numbers. See, in general, + + + align:start position:0% +these rational numbers. See, in general, +as systems designers, + + align:start position:0% + + + + align:start position:0% + +you're forced with the necessity to make + + align:start position:0% +you're forced with the necessity to make + + + align:start position:0% +you're forced with the necessity to make +decisions about how you're going to do + + align:start position:0% +decisions about how you're going to do + + + align:start position:0% +decisions about how you're going to do +things. And in general, the way you'd + + align:start position:0% +things. And in general, the way you'd + + + align:start position:0% +things. And in general, the way you'd +like to retain flexibility is to never + + align:start position:0% +like to retain flexibility is to never + + + align:start position:0% +like to retain flexibility is to never +make up your mind about anything until + + align:start position:0% +make up your mind about anything until + + + align:start position:0% +make up your mind about anything until +you're forced to do it. + + align:start position:0% +you're forced to do it. + + + align:start position:0% +you're forced to do it. +And the problem is there's a a very, + + align:start position:0% +And the problem is there's a a very, + + + align:start position:0% +And the problem is there's a a very, +very narrow line between deferring + + align:start position:0% +very narrow line between deferring + + + align:start position:0% +very narrow line between deferring +decisions and outright procrastination. + + align:start position:0% + + + + align:start position:0% + +So you'd like to make progress. + + align:start position:0% +So you'd like to make progress. + + + align:start position:0% +So you'd like to make progress. +You'd like to make progress but also at + + align:start position:0% +You'd like to make progress but also at + + + align:start position:0% +You'd like to make progress but also at +the same time never be bound by the + + align:start position:0% +the same time never be bound by the + + + align:start position:0% +the same time never be bound by the +consequences of your decisions. + + align:start position:0% +consequences of your decisions. + + + align:start position:0% +consequences of your decisions. +Data abstraction is one way of doing + + align:start position:0% +Data abstraction is one way of doing + + + align:start position:0% +Data abstraction is one way of doing +this. What we did is we used wishful + + align:start position:0% +this. What we did is we used wishful + + + align:start position:0% +this. What we did is we used wishful +thinking. + + align:start position:0% +thinking. + + + align:start position:0% +thinking. +See we gave a name to the decision. We + + align:start position:0% +See we gave a name to the decision. We + + + align:start position:0% +See we gave a name to the decision. We +said make rat numerator and denominator + + align:start position:0% +said make rat numerator and denominator + + + align:start position:0% +said make rat numerator and denominator +will stand for however it's going to be + + align:start position:0% +will stand for however it's going to be + + + align:start position:0% +will stand for however it's going to be +done. And however it's going to be done + + align:start position:0% +done. And however it's going to be done + + + align:start position:0% +done. And however it's going to be done +it's George's problem. Really what that + + align:start position:0% +it's George's problem. Really what that + + + align:start position:0% +it's George's problem. Really what that +was doing is giving a name to the + + align:start position:0% +was doing is giving a name to the + + + align:start position:0% +was doing is giving a name to the +decision of how we're going to do it + + align:start position:0% +decision of how we're going to do it + + + align:start position:0% +decision of how we're going to do it +and then continuing as if we'd made the + + align:start position:0% +and then continuing as if we'd made the + + + align:start position:0% +and then continuing as if we'd made the +decision come and then eventually when + + align:start position:0% +decision come and then eventually when + + + align:start position:0% +decision come and then eventually when +we really wanted it to work coming back + + align:start position:0% +we really wanted it to work coming back + + + align:start position:0% +we really wanted it to work coming back +and facing what we really had to do + + align:start position:0% +and facing what we really had to do + + + align:start position:0% +and facing what we really had to do +and in fact we'll see a couple of times + + align:start position:0% +and in fact we'll see a couple of times + + + align:start position:0% +and in fact we'll see a couple of times +from now that you may never have to + + align:start position:0% +from now that you may never have to + + + align:start position:0% +from now that you may never have to +choose any particular representation + + align:start position:0% +choose any particular representation + + + align:start position:0% +choose any particular representation +ever ever. + + align:start position:0% +ever ever. + + + align:start position:0% +ever ever. +Anyway, that's a very powerful design + + align:start position:0% +Anyway, that's a very powerful design + + + align:start position:0% +Anyway, that's a very powerful design +technique. It's the key to the reason + + align:start position:0% +technique. It's the key to the reason + + + align:start position:0% +technique. It's the key to the reason +people use data abstraction. + + align:start position:0% +people use data abstraction. + + + align:start position:0% +people use data abstraction. +And we're going to see that idea again + + align:start position:0% +And we're going to see that idea again + + + align:start position:0% +And we're going to see that idea again +and again. + + align:start position:0% +and again. + + + align:start position:0% +and again. +Let's stop for questions. + + align:start position:0% +Let's stop for questions. + + + align:start position:0% +Let's stop for questions. +What does this um decision making + + align:start position:0% +What does this um decision making + + + align:start position:0% +What does this um decision making +through abstraction layers do to the + + align:start position:0% +through abstraction layers do to the + + + align:start position:0% +through abstraction layers do to the +maximum of do all your design before any + + align:start position:0% +maximum of do all your design before any + + + align:start position:0% +maximum of do all your design before any +of your code? + + align:start position:0% +of your code? + + + align:start position:0% +of your code? +Well, that's someone's axiom and I bet + + align:start position:0% +Well, that's someone's axiom and I bet + + + align:start position:0% +Well, that's someone's axiom and I bet +that's the axiom of someone who hasn't + + align:start position:0% +that's the axiom of someone who hasn't + + + align:start position:0% +that's the axiom of someone who hasn't +implemented very large computer systems + + align:start position:0% +implemented very large computer systems + + + align:start position:0% +implemented very large computer systems +very much. + + align:start position:0% +very much. + + + align:start position:0% +very much. +uh + + align:start position:0% +uh + + + align:start position:0% +uh +said that computer science is a lot like + + align:start position:0% +said that computer science is a lot like + + + align:start position:0% +said that computer science is a lot like +magic and it's sort of good that it's + + align:start position:0% +magic and it's sort of good that it's + + + align:start position:0% +magic and it's sort of good that it's +like magic. There's a bad part of + + align:start position:0% +like magic. There's a bad part of + + + align:start position:0% +like magic. There's a bad part of +computer science that's a lot like + + align:start position:0% +computer science that's a lot like + + + align:start position:0% +computer science that's a lot like +religion and uh + + align:start position:0% +religion and uh + + + align:start position:0% +religion and uh +but uh in general I think people who + + align:start position:0% +but uh in general I think people who + + + align:start position:0% +but uh in general I think people who +really believe that you design + + align:start position:0% +really believe that you design + + + align:start position:0% +really believe that you design +everything before you implement it + + align:start position:0% +everything before you implement it + + + align:start position:0% +everything before you implement it +basically are people who haven't + + align:start position:0% +basically are people who haven't + + + align:start position:0% +basically are people who haven't +designed very many things. + + align:start position:0% +designed very many things. + + + align:start position:0% +designed very many things. +The real the real power is that you can + + align:start position:0% +The real the real power is that you can + + + align:start position:0% +The real the real power is that you can +pretend that you've made the decision + + align:start position:0% +pretend that you've made the decision + + + align:start position:0% +pretend that you've made the decision +and then later on figure out which one + + align:start position:0% +and then later on figure out which one + + + align:start position:0% +and then later on figure out which one +is right, which decision you ought to + + align:start position:0% +is right, which decision you ought to + + + align:start position:0% +is right, which decision you ought to +have made. And when you can do that, you + + align:start position:0% +have made. And when you can do that, you + + + align:start position:0% +have made. And when you can do that, you +have the best of both worlds. + + align:start position:0% + + + + align:start position:0% + +Can you explain the difference between + + align:start position:0% +Can you explain the difference between + + + align:start position:0% +Can you explain the difference between +let and define? + + align:start position:0% +let and define? + + + align:start position:0% +let and define? +Oh, okay. Uh, + + align:start position:0% +Oh, okay. Uh, + + + align:start position:0% +Oh, okay. Uh, +let is + + align:start position:0% +let is + + + align:start position:0% +let is +let is a way to to establish local + + align:start position:0% +let is a way to to establish local + + + align:start position:0% +let is a way to to establish local +names. + + align:start position:0% + + + + align:start position:0% + +Okay. So there let me give you sort of + + align:start position:0% +Okay. So there let me give you sort of + + + align:start position:0% +Okay. So there let me give you sort of +the half answer and I'll say maybe we + + align:start position:0% +the half answer and I'll say maybe we + + + align:start position:0% +the half answer and I'll say maybe we +later on we can talk about the whole + + align:start position:0% +later on we can talk about the whole + + + align:start position:0% +later on we can talk about the whole +very complicated thing but the big + + align:start position:0% +very complicated thing but the big + + + align:start position:0% +very complicated thing but the big +difference for now is that see when + + align:start position:0% +difference for now is that see when + + + align:start position:0% +difference for now is that see when +you're typing at lisp you're typing in + + align:start position:0% +you're typing at lisp you're typing in + + + align:start position:0% +you're typing at lisp you're typing in +this this environment where you're + + align:start position:0% +this this environment where you're + + + align:start position:0% +this this environment where you're +making definitions and when you say + + align:start position:0% +making definitions and when you say + + + align:start position:0% +making definitions and when you say +define a to be five + + align:start position:0% +define a to be five + + + align:start position:0% +define a to be five +if I say define + + align:start position:0% +if I say define + + + align:start position:0% +if I say define +a to be five + + align:start position:0% +a to be five + + + align:start position:0% +a to be five +then from then on the thing will + + align:start position:0% +then from then on the thing will + + + align:start position:0% +then from then on the thing will +remember that a is five. + + align:start position:0% +remember that a is five. + + + align:start position:0% +remember that a is five. +Okay, let is a way to set up a local + + align:start position:0% +Okay, let is a way to set up a local + + + align:start position:0% +Okay, let is a way to set up a local +context where there's a definition. So + + align:start position:0% +context where there's a definition. So + + + align:start position:0% +context where there's a definition. So +if I type something like saying let + + align:start position:0% +if I type something like saying let + + + align:start position:0% +if I type something like saying let +um let A no I shouldn't say A. + + align:start position:0% + + + + align:start position:0% + +If I said let let Z be tan + + align:start position:0% + + + + align:start position:0% + +and within that context tell me what the + + align:start position:0% +and within that context tell me what the + + + align:start position:0% +and within that context tell me what the +sum of Z and Z is. So if I typed in this + + align:start position:0% +sum of Z and Z is. So if I typed in this + + + align:start position:0% +sum of Z and Z is. So if I typed in this +expression to lisp + + align:start position:0% +expression to lisp + + + align:start position:0% +expression to lisp +and then this would put out 20. However, + + align:start position:0% +and then this would put out 20. However, + + + align:start position:0% +and then this would put out 20. However, +then if I said what's Z, the computer + + align:start position:0% +then if I said what's Z, the computer + + + align:start position:0% +then if I said what's Z, the computer +would say that's an unbound variable. + + align:start position:0% +would say that's an unbound variable. + + + align:start position:0% +would say that's an unbound variable. +So let is a way of setting up a context + + align:start position:0% +So let is a way of setting up a context + + + align:start position:0% +So let is a way of setting up a context +where you can make definitions, + + align:start position:0% +where you can make definitions, + + + align:start position:0% +where you can make definitions, +but those definitions are local to this + + align:start position:0% +but those definitions are local to this + + + align:start position:0% +but those definitions are local to this +context. And of course, if I'd said a in + + align:start position:0% +context. And of course, if I'd said a in + + + align:start position:0% +context. And of course, if I'd said a in +here, + + align:start position:0% + + + + align:start position:0% + +I'd still get 20. But this A + + align:start position:0% +I'd still get 20. But this A + + + align:start position:0% +I'd still get 20. But this A +would not interfere at all with this + + align:start position:0% +would not interfere at all with this + + + align:start position:0% +would not interfere at all with this +one. + + align:start position:0% +one. + + + align:start position:0% +one. +So if I type this and then type this and + + align:start position:0% +So if I type this and then type this and + + + align:start position:0% +So if I type this and then type this and +then say what's a, a will still be five. + + align:start position:0% +then say what's a, a will still be five. + + + align:start position:0% +then say what's a, a will still be five. +So that's there's some other subtle + + align:start position:0% +So that's there's some other subtle + + + align:start position:0% +So that's there's some other subtle +differences between let and define, but + + align:start position:0% +differences between let and define, but + + + align:start position:0% +differences between let and define, but +that's the the most important one. + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +All right. Well, we've looked at + + align:start position:0% +All right. Well, we've looked at + + + align:start position:0% +All right. Well, we've looked at +implementing this this little system for + + align:start position:0% +implementing this this little system for + + + align:start position:0% +implementing this this little system for +doing arithmetic on rational numbers as + + align:start position:0% +doing arithmetic on rational numbers as + + + align:start position:0% +doing arithmetic on rational numbers as +an example of this methodology of data + + align:start position:0% +an example of this methodology of data + + + align:start position:0% +an example of this methodology of data +abstraction. + + align:start position:0% +abstraction. + + + align:start position:0% +abstraction. +And that's a way of controlling + + align:start position:0% +And that's a way of controlling + + + align:start position:0% +And that's a way of controlling +complexity in large systems. + + align:start position:0% +complexity in large systems. + + + align:start position:0% +complexity in large systems. +But see like procedure definition and + + align:start position:0% +But see like procedure definition and + + + align:start position:0% +But see like procedure definition and +like all the ways we're going to talk + + align:start position:0% +like all the ways we're going to talk + + + align:start position:0% +like all the ways we're going to talk +about for controlling complexity the + + align:start position:0% +about for controlling complexity the + + + align:start position:0% +about for controlling complexity the +real power of these things show up not + + align:start position:0% +real power of these things show up not + + + align:start position:0% +real power of these things show up not +when you sort of do these things in + + align:start position:0% +when you sort of do these things in + + + align:start position:0% +when you sort of do these things in +themselves like it's you know it's not + + align:start position:0% +themselves like it's you know it's not + + + align:start position:0% +themselves like it's you know it's not +such a great thing that we've done + + align:start position:0% +such a great thing that we've done + + + align:start position:0% +such a great thing that we've done +rational number arithmetic + + align:start position:0% +rational number arithmetic + + + align:start position:0% +rational number arithmetic +it's that you can use these as building + + align:start position:0% +it's that you can use these as building + + + align:start position:0% +it's that you can use these as building +blocks for making more complicated + + align:start position:0% +blocks for making more complicated + + + align:start position:0% +blocks for making more complicated +things. + + align:start position:0% +things. + + + align:start position:0% +things. +Right? So it's no wonderful idea that + + align:start position:0% +Right? So it's no wonderful idea that + + + align:start position:0% +Right? So it's no wonderful idea that +you can just put two numbers together to + + align:start position:0% +you can just put two numbers together to + + + align:start position:0% +you can just put two numbers together to +form a pair if that's all you ever + + align:start position:0% +form a pair if that's all you ever + + + align:start position:0% +form a pair if that's all you ever +wanted to do. There are tons of ways + + align:start position:0% +wanted to do. There are tons of ways + + + align:start position:0% +wanted to do. There are tons of ways +that you can do that. The real issue is + + align:start position:0% +that you can do that. The real issue is + + + align:start position:0% +that you can do that. The real issue is +can you do that in such a way so that + + align:start position:0% +can you do that in such a way so that + + + align:start position:0% +can you do that in such a way so that +the things that you build become + + align:start position:0% +the things that you build become + + + align:start position:0% +the things that you build become +building blocks for doing something even + + align:start position:0% +building blocks for doing something even + + + align:start position:0% +building blocks for doing something even +even more complex. So whenever someone + + align:start position:0% +even more complex. So whenever someone + + + align:start position:0% +even more complex. So whenever someone +shows you a method for controlling + + align:start position:0% +shows you a method for controlling + + + align:start position:0% +shows you a method for controlling +complexity, you should say, "Yeah, + + align:start position:0% +complexity, you should say, "Yeah, + + + align:start position:0% +complexity, you should say, "Yeah, +that's great, but what can I build with + + align:start position:0% +that's great, but what can I build with + + + align:start position:0% +that's great, but what can I build with +it?" + + align:start position:0% +it?" + + + align:start position:0% +it?" +Okay, so for example, + + align:start position:0% +Okay, so for example, + + + align:start position:0% +Okay, so for example, +let's do a let me just run through + + align:start position:0% +let's do a let me just run through + + + align:start position:0% +let's do a let me just run through +another thing that's a lot like the + + align:start position:0% +another thing that's a lot like the + + + align:start position:0% +another thing that's a lot like the +rational number one. Suppose we would + + align:start position:0% +rational number one. Suppose we would + + + align:start position:0% +rational number one. Suppose we would +like to represent uh you know points in + + align:start position:0% +like to represent uh you know points in + + + align:start position:0% +like to represent uh you know points in +the plane. you sort of say, well, + + align:start position:0% +the plane. you sort of say, well, + + + align:start position:0% +the plane. you sort of say, well, +there's a point and we're going to call + + align:start position:0% +there's a point and we're going to call + + + align:start position:0% +there's a point and we're going to call +that point P + + align:start position:0% +that point P + + + align:start position:0% +that point P +and uh + + align:start position:0% +and uh + + + align:start position:0% +and uh +that that point might have coordinates + + align:start position:0% +that that point might have coordinates + + + align:start position:0% +that that point might have coordinates +like uh this might be the point one + + align:start position:0% +like uh this might be the point one + + + align:start position:0% +like uh this might be the point one +comma 2. Its x coordinate might be one + + align:start position:0% +comma 2. Its x coordinate might be one + + + align:start position:0% +comma 2. Its x coordinate might be one +and its ycoordinate might be two. And + + align:start position:0% +and its ycoordinate might be two. And + + + align:start position:0% +and its ycoordinate might be two. And +then we'll make a little system for for + + align:start position:0% +then we'll make a little system for for + + + align:start position:0% +then we'll make a little system for for +manipulating points in the plane. + + align:start position:0% +manipulating points in the plane. + + + align:start position:0% +manipulating points in the plane. +And again, we can do that. Here's a + + align:start position:0% +And again, we can do that. Here's a + + + align:start position:0% +And again, we can do that. Here's a +here's a little example of that. + + align:start position:0% + + + + align:start position:0% + +can represent vectors that's the same as + + align:start position:0% +can represent vectors that's the same as + + + align:start position:0% +can represent vectors that's the same as +points in the plane. And we'll say, yep, + + align:start position:0% +points in the plane. And we'll say, yep, + + + align:start position:0% +points in the plane. And we'll say, yep, +there's a + + align:start position:0% +there's a + + + align:start position:0% +there's a +there's a constructor + + align:start position:0% +there's a constructor + + + align:start position:0% +there's a constructor +called make vector. Make vector is going + + align:start position:0% +called make vector. Make vector is going + + + align:start position:0% +called make vector. Make vector is going +to take two coordinates. + + align:start position:0% +to take two coordinates. + + + align:start position:0% +to take two coordinates. +And here we can implement them if we + + align:start position:0% +And here we can implement them if we + + + align:start position:0% +And here we can implement them if we +like as pairs. But the important thing + + align:start position:0% +like as pairs. But the important thing + + + align:start position:0% +like as pairs. But the important thing +is that there's a constructor. + + align:start position:0% +is that there's a constructor. + + + align:start position:0% +is that there's a constructor. +And then given some vector p, we can + + align:start position:0% +And then given some vector p, we can + + + align:start position:0% +And then given some vector p, we can +find its x coordinate + + align:start position:0% +find its x coordinate + + + align:start position:0% +find its x coordinate +or we can get its ycoordinate. So + + align:start position:0% +or we can get its ycoordinate. So + + + align:start position:0% +or we can get its ycoordinate. So +there's a constructor and selectors for + + align:start position:0% +there's a constructor and selectors for + + + align:start position:0% +there's a constructor and selectors for +points on the plane. + + align:start position:0% +points on the plane. + + + align:start position:0% +points on the plane. +Well, given points in the plane, we + + align:start position:0% +Well, given points in the plane, we + + + align:start position:0% +Well, given points in the plane, we +might want to use them to build + + align:start position:0% +might want to use them to build + + + align:start position:0% +might want to use them to build +something. So for instance, we might + + align:start position:0% +something. So for instance, we might + + + align:start position:0% +something. So for instance, we might +want to talk about we might have a point + + align:start position:0% +want to talk about we might have a point + + + align:start position:0% +want to talk about we might have a point +P and a point Q. So P might be the point + + align:start position:0% +P and a point Q. So P might be the point + + + align:start position:0% +P and a point Q. So P might be the point +one, two, and Q might be the point 23. + + align:start position:0% +one, two, and Q might be the point 23. + + + align:start position:0% +one, two, and Q might be the point 23. +And we might want to talk about the line + + align:start position:0% +And we might want to talk about the line + + + align:start position:0% +And we might want to talk about the line +segment that starts at P and ends at Q, + + align:start position:0% +segment that starts at P and ends at Q, + + + align:start position:0% +segment that starts at P and ends at Q, +right? Right? And that might be the + + align:start position:0% +right? Right? And that might be the + + + align:start position:0% +right? Right? And that might be the +segment S. + + align:start position:0% +segment S. + + + align:start position:0% +segment S. +So we might want to build points in + + align:start position:0% +So we might want to build points in + + + align:start position:0% +So we might want to build points in +terms of numbers and segments in terms + + align:start position:0% +terms of numbers and segments in terms + + + align:start position:0% +terms of numbers and segments in terms +we might want to build points or vectors + + align:start position:0% +we might want to build points or vectors + + + align:start position:0% +we might want to build points or vectors +in terms of numbers and segments in + + align:start position:0% +in terms of numbers and segments in + + + align:start position:0% +in terms of numbers and segments in +terms of vectors. + + align:start position:0% +terms of vectors. + + + align:start position:0% +terms of vectors. +So we can represent line segments in + + align:start position:0% +So we can represent line segments in + + + align:start position:0% +So we can represent line segments in +exactly the same way. Right? So the line + + align:start position:0% +exactly the same way. Right? So the line + + + align:start position:0% +exactly the same way. Right? So the line +segment from P to Q. We'll say there's a + + align:start position:0% +segment from P to Q. We'll say there's a + + + align:start position:0% +segment from P to Q. We'll say there's a +constructor make segment + + align:start position:0% + + + + align:start position:0% + +and there's make up names for the + + align:start position:0% +and there's make up names for the + + + align:start position:0% +and there's make up names for the +selectors. starting point of the segment + + align:start position:0% +selectors. starting point of the segment + + + align:start position:0% +selectors. starting point of the segment +and the ending point of the segment. And + + align:start position:0% +and the ending point of the segment. And + + + align:start position:0% +and the ending point of the segment. And +again, we can implement a segment using + + align:start position:0% +again, we can implement a segment using + + + align:start position:0% +again, we can implement a segment using +con as a pair of points + + align:start position:0% +con as a pair of points + + + align:start position:0% +con as a pair of points +and car and cooter get out the two + + align:start position:0% +and car and cooter get out the two + + + align:start position:0% +and car and cooter get out the two +points that we put together to get the + + align:start position:0% +points that we put together to get the + + + align:start position:0% +points that we put together to get the +segment. + + align:start position:0% + + + + align:start position:0% + +Well, now having done that, + + align:start position:0% +Well, now having done that, + + + align:start position:0% +Well, now having done that, +we can have some operations on them, + + align:start position:0% +we can have some operations on them, + + + align:start position:0% +we can have some operations on them, +right? Like we could say what's the + + align:start position:0% +right? Like we could say what's the + + + align:start position:0% +right? Like we could say what's the +what's the midpoint of a line segment? + + align:start position:0% +what's the midpoint of a line segment? + + + align:start position:0% +what's the midpoint of a line segment? +So here's the midpoint of a line + + align:start position:0% +So here's the midpoint of a line + + + align:start position:0% +So here's the midpoint of a line +segment. That's going to be the point + + align:start position:0% +segment. That's going to be the point + + + align:start position:0% +segment. That's going to be the point +that well the points whose coordinates + + align:start position:0% +that well the points whose coordinates + + + align:start position:0% +that well the points whose coordinates +are the averages of the coordinates of + + align:start position:0% +are the averages of the coordinates of + + + align:start position:0% +are the averages of the coordinates of +the end points. There's the midpoint. + + align:start position:0% +the end points. There's the midpoint. + + + align:start position:0% +the end points. There's the midpoint. +So to get the midpoint of a line segment + + align:start position:0% +So to get the midpoint of a line segment + + + align:start position:0% +So to get the midpoint of a line segment +S, + + align:start position:0% +S, + + + align:start position:0% +S, +we'll just say grab the starting point + + align:start position:0% +we'll just say grab the starting point + + + align:start position:0% +we'll just say grab the starting point +of the segment, grab the ending point of + + align:start position:0% +of the segment, grab the ending point of + + + align:start position:0% +of the segment, grab the ending point of +the segment, + + align:start position:0% +the segment, + + + align:start position:0% +the segment, +and now make a vector, right? make a + + align:start position:0% +and now make a vector, right? make a + + + align:start position:0% +and now make a vector, right? make a +point whose coordinates are the average + + align:start position:0% +point whose coordinates are the average + + + align:start position:0% +point whose coordinates are the average +of the x coordinate of the first point + + align:start position:0% +of the x coordinate of the first point + + + align:start position:0% +of the x coordinate of the first point +and the x coordinate of the second point + + align:start position:0% +and the x coordinate of the second point + + + align:start position:0% +and the x coordinate of the second point +and whose y-coordinate is the average of + + align:start position:0% +and whose y-coordinate is the average of + + + align:start position:0% +and whose y-coordinate is the average of +the y-coordinates. + + align:start position:0% +the y-coordinates. + + + align:start position:0% +the y-coordinates. +So there's an implementation of midpoint + + align:start position:0% +So there's an implementation of midpoint + + + align:start position:0% +So there's an implementation of midpoint +and then and then similarly + + align:start position:0% +and then and then similarly + + + align:start position:0% +and then and then similarly +we can build something like the length + + align:start position:0% +we can build something like the length + + + align:start position:0% +we can build something like the length +of a segment right the length of a + + align:start position:0% +of a segment right the length of a + + + align:start position:0% +of a segment right the length of a +segment is a thing whose + + align:start position:0% + + + + align:start position:0% + +right we use use Pythagoras's rule the + + align:start position:0% +right we use use Pythagoras's rule the + + + align:start position:0% +right we use use Pythagoras's rule the +length of the segment is a square root + + align:start position:0% +length of the segment is a square root + + + align:start position:0% +length of the segment is a square root +of dx^2 plus dy^2 we'll say to get the + + align:start position:0% +of dx^2 plus dy^2 we'll say to get the + + + align:start position:0% +of dx^2 plus dy^2 we'll say to get the +length of a line segment well we'll let + + align:start position:0% +length of a line segment well we'll let + + + align:start position:0% +length of a line segment well we'll let +dx be the difference of the xcoordinate + + align:start position:0% +dx be the difference of the xcoordinate + + + align:start position:0% +dx be the difference of the xcoordinate +of one endpoint + + align:start position:0% +of one endpoint + + + align:start position:0% +of one endpoint +and the x coordinate of the other end + + align:start position:0% +and the x coordinate of the other end + + + align:start position:0% +and the x coordinate of the other end +point and we'll let dy be the difference + + align:start position:0% +point and we'll let dy be the difference + + + align:start position:0% +point and we'll let dy be the difference +of the ycoordinates + + align:start position:0% +of the ycoordinates + + + align:start position:0% +of the ycoordinates +and then we'll take the square root of + + align:start position:0% +and then we'll take the square root of + + + align:start position:0% +and then we'll take the square root of +the sum of the squares of dx and dy. + + align:start position:0% +the sum of the squares of dx and dy. + + + align:start position:0% +the sum of the squares of dx and dy. +That's what this says, right? So there's + + align:start position:0% +That's what this says, right? So there's + + + align:start position:0% +That's what this says, right? So there's +an implementation of length + + align:start position:0% +an implementation of length + + + align:start position:0% +an implementation of length +and again + + align:start position:0% + + + + align:start position:0% + +what we built is a layered system + + align:start position:0% +what we built is a layered system + + + align:start position:0% +what we built is a layered system +right we built a system which has well + + align:start position:0% +right we built a system which has well + + + align:start position:0% +right we built a system which has well +say up here there are segments + + align:start position:0% + + + + align:start position:0% + +and then there's an abstraction barrier + + align:start position:0% +and then there's an abstraction barrier + + + align:start position:0% +and then there's an abstraction barrier +right the abstraction barrier barrier + + align:start position:0% +right the abstraction barrier barrier + + + align:start position:0% +right the abstraction barrier barrier +separates + + align:start position:0% +separates + + + align:start position:0% +separates +the implementation + + align:start position:0% +the implementation + + + align:start position:0% +the implementation +of segments from the implementation of + + align:start position:0% +of segments from the implementation of + + + align:start position:0% +of segments from the implementation of +vectors and points. And what that + + align:start position:0% +vectors and points. And what that + + + align:start position:0% +vectors and points. And what that +abstraction barrier is + + align:start position:0% +abstraction barrier is + + + align:start position:0% +abstraction barrier is +are the constructors and selectors. It's + + align:start position:0% +are the constructors and selectors. It's + + + align:start position:0% +are the constructors and selectors. It's +make segment + + align:start position:0% +make segment + + + align:start position:0% +make segment +and segment start + + align:start position:0% + + + + align:start position:0% + +and segment end, + + align:start position:0% + + + + align:start position:0% + +right? And then there are vectors. And + + align:start position:0% +right? And then there are vectors. And + + + align:start position:0% +right? And then there are vectors. And +then vectors in turn are built on top of + + align:start position:0% +then vectors in turn are built on top of + + + align:start position:0% +then vectors in turn are built on top of +pairs and numbers. So let's say pairs + + align:start position:0% +pairs and numbers. So let's say pairs + + + align:start position:0% +pairs and numbers. So let's say pairs +and numbers. And that has its own + + align:start position:0% +and numbers. And that has its own + + + align:start position:0% +and numbers. And that has its own +abstraction barrier, right? Which is + + align:start position:0% +abstraction barrier, right? Which is + + + align:start position:0% +abstraction barrier, right? Which is +make vector + + align:start position:0% + + + + align:start position:0% + +and x coordinate + + align:start position:0% +and x coordinate + + + align:start position:0% +and x coordinate +and ycoordinate. + + align:start position:0% + + + + align:start position:0% + +Right? So we have again a layered + + align:start position:0% +Right? So we have again a layered + + + align:start position:0% +Right? So we have again a layered +system. You're starting to see that + + align:start position:0% +system. You're starting to see that + + + align:start position:0% +system. You're starting to see that +there are layers here. I ought to + + align:start position:0% +there are layers here. I ought to + + + align:start position:0% +there are layers here. I ought to +mention there's a very important thing + + align:start position:0% + + + + align:start position:0% + +that I kind of took for granted + + align:start position:0% +that I kind of took for granted + + + align:start position:0% +that I kind of took for granted +and it's + + align:start position:0% +and it's + + + align:start position:0% +and it's +it's sort of so natural. On the other + + align:start position:0% +it's sort of so natural. On the other + + + align:start position:0% +it's sort of so natural. On the other +hand, it's it's one it's a very + + align:start position:0% +hand, it's it's one it's a very + + + align:start position:0% +hand, it's it's one it's a very +important thing. Notice that in order to + + align:start position:0% +important thing. Notice that in order to + + + align:start position:0% +important thing. Notice that in order to +represent the segment S, + + align:start position:0% +represent the segment S, + + + align:start position:0% +represent the segment S, +I said this segment is a pair of points + + align:start position:0% +I said this segment is a pair of points + + + align:start position:0% +I said this segment is a pair of points +and a point is a pair of numbers. And if + + align:start position:0% +and a point is a pair of numbers. And if + + + align:start position:0% +and a point is a pair of numbers. And if +I were going to draw the box and + + align:start position:0% +I were going to draw the box and + + + align:start position:0% +I were going to draw the box and +pointers structure for that, I would + + align:start position:0% +pointers structure for that, I would + + + align:start position:0% +pointers structure for that, I would +say, oh, the segment is given those + + align:start position:0% +say, oh, the segment is given those + + + align:start position:0% +say, oh, the segment is given those +particular representations that I showed + + align:start position:0% +particular representations that I showed + + + align:start position:0% +particular representations that I showed +you, I'd say this segment S is a pair. + + align:start position:0% +you, I'd say this segment S is a pair. + + + align:start position:0% +you, I'd say this segment S is a pair. +And the first thing in the pair is + + align:start position:0% +And the first thing in the pair is + + + align:start position:0% +And the first thing in the pair is +a vector. + + align:start position:0% +a vector. + + + align:start position:0% +a vector. +And the vector is + + align:start position:0% +And the vector is + + + align:start position:0% +And the vector is +a pair of numbers. + + align:start position:0% +a pair of numbers. + + + align:start position:0% +a pair of numbers. +That's this. That's P. + + align:start position:0% + + + + align:start position:0% + +And the other thing in the segment is Q + + align:start position:0% +And the other thing in the segment is Q + + + align:start position:0% +And the other thing in the segment is Q +which is itself a pair + + align:start position:0% +which is itself a pair + + + align:start position:0% +which is itself a pair +of numbers. + + align:start position:0% +of numbers. + + + align:start position:0% +of numbers. +So I almost took it for granted when I + + align:start position:0% +So I almost took it for granted when I + + + align:start position:0% +So I almost took it for granted when I +said that Kant allows you to put things + + align:start position:0% +said that Kant allows you to put things + + + align:start position:0% +said that Kant allows you to put things +together. + + align:start position:0% +together. + + + align:start position:0% +together. +But it's very easy to not appreciate + + align:start position:0% +But it's very easy to not appreciate + + + align:start position:0% +But it's very easy to not appreciate +that because notice I can put some of + + align:start position:0% +that because notice I can put some of + + + align:start position:0% +that because notice I can put some of +the things I can put together can + + align:start position:0% +the things I can put together can + + + align:start position:0% +the things I can put together can +themselves be pairs. + + align:start position:0% +themselves be pairs. + + + align:start position:0% +themselves be pairs. +And let me introduce a word that I'll + + align:start position:0% +And let me introduce a word that I'll + + + align:start position:0% +And let me introduce a word that I'll +talk about more next time. It's one of + + align:start position:0% +talk about more next time. It's one of + + + align:start position:0% +talk about more next time. It's one of +my my favorite words called closure. + + align:start position:0% + + + + align:start position:0% + +And by closure I mean that the means of + + align:start position:0% +And by closure I mean that the means of + + + align:start position:0% +And by closure I mean that the means of +combination in your system are such that + + align:start position:0% +combination in your system are such that + + + align:start position:0% +combination in your system are such that +when you put things together using them + + align:start position:0% +when you put things together using them + + + align:start position:0% +when you put things together using them +like you make a pair + + align:start position:0% +like you make a pair + + + align:start position:0% +like you make a pair +you can then put those together with the + + align:start position:0% +you can then put those together with the + + + align:start position:0% +you can then put those together with the +same means of combination. So I can have + + align:start position:0% +same means of combination. So I can have + + + align:start position:0% +same means of combination. So I can have +not only a pair of numbers but I can + + align:start position:0% +not only a pair of numbers but I can + + + align:start position:0% +not only a pair of numbers but I can +have a pair of pairs. + + align:start position:0% + + + + align:start position:0% + +So for instance uh + + align:start position:0% +So for instance uh + + + align:start position:0% +So for instance uh +making arrays in a language like forran + + align:start position:0% +making arrays in a language like forran + + + align:start position:0% +making arrays in a language like forran +is not a closed means of combination + + align:start position:0% +is not a closed means of combination + + + align:start position:0% +is not a closed means of combination +because I can make an array of numbers + + align:start position:0% +because I can make an array of numbers + + + align:start position:0% +because I can make an array of numbers +but I can't make an array of arrays + + align:start position:0% + + + + align:start position:0% + +and one of the things that you should + + align:start position:0% +and one of the things that you should + + + align:start position:0% +and one of the things that you should +ask one of your one of your tests of + + align:start position:0% +ask one of your one of your tests of + + + align:start position:0% +ask one of your one of your tests of +quality for a means of combination that + + align:start position:0% +quality for a means of combination that + + + align:start position:0% +quality for a means of combination that +someone shows you is gee are the things + + align:start position:0% +someone shows you is gee are the things + + + align:start position:0% +someone shows you is gee are the things +you make closed under that means of + + align:start position:0% +you make closed under that means of + + + align:start position:0% +you make closed under that means of +combination so it's not so Paris would + + align:start position:0% +combination so it's not so Paris would + + + align:start position:0% +combination so it's not so Paris would +not be nearly so interesting if all I + + align:start position:0% +not be nearly so interesting if all I + + + align:start position:0% +not be nearly so interesting if all I +could do was make a pair of numbers. I + + align:start position:0% +could do was make a pair of numbers. I + + + align:start position:0% +could do was make a pair of numbers. I +couldn't build very much structure at + + align:start position:0% +couldn't build very much structure at + + + align:start position:0% +couldn't build very much structure at +all. + + align:start position:0% +all. + + + align:start position:0% +all. +Okay. Well, we'll come back to that. I + + align:start position:0% +Okay. Well, we'll come back to that. I + + + align:start position:0% +Okay. Well, we'll come back to that. I +just wanted to mention it now. You'll + + align:start position:0% +just wanted to mention it now. You'll + + + align:start position:0% +just wanted to mention it now. You'll +hear a lot about closure later on. You + + align:start position:0% +hear a lot about closure later on. You + + + align:start position:0% +hear a lot about closure later on. You +can also see + + align:start position:0% +can also see + + + align:start position:0% +can also see +the potential for losing control of + + align:start position:0% +the potential for losing control of + + + align:start position:0% +the potential for losing control of +complexity as soon as you have a layered + + align:start position:0% +complexity as soon as you have a layered + + + align:start position:0% +complexity as soon as you have a layered +system if you don't use data + + align:start position:0% +system if you don't use data + + + align:start position:0% +system if you don't use data +abstraction. + + align:start position:0% +abstraction. + + + align:start position:0% +abstraction. +See, let's go back and let's go back and + + align:start position:0% +See, let's go back and let's go back and + + + align:start position:0% +See, let's go back and let's go back and +look at this slide for length. See, + + align:start position:0% +look at this slide for length. See, + + + align:start position:0% +look at this slide for length. See, +length length works and is a simple + + align:start position:0% +length length works and is a simple + + + align:start position:0% +length length works and is a simple +thing. + + align:start position:0% +thing. + + + align:start position:0% +thing. +Because I can say when I want to get + + align:start position:0% +Because I can say when I want to get + + + align:start position:0% +Because I can say when I want to get +this value I can say oh that is the + + align:start position:0% +this value I can say oh that is the + + + align:start position:0% +this value I can say oh that is the +x-coordinate + + align:start position:0% +x-coordinate + + + align:start position:0% +x-coordinate +of the first endpoint of the segment + + align:start position:0% +of the first endpoint of the segment + + + align:start position:0% +of the first endpoint of the segment +and each of these things each of these + + align:start position:0% +and each of these things each of these + + + align:start position:0% +and each of these things each of these +selectors x-coordinate and endpoint + + align:start position:0% +selectors x-coordinate and endpoint + + + align:start position:0% +selectors x-coordinate and endpoint +stand for a decision choice whose + + align:start position:0% +stand for a decision choice whose + + + align:start position:0% +stand for a decision choice whose +details I don't have to look at. See, I + + align:start position:0% +details I don't have to look at. See, I + + + align:start position:0% +details I don't have to look at. See, I +could perfectly well, again, just like + + align:start position:0% +could perfectly well, again, just like + + + align:start position:0% +could perfectly well, again, just like +rational numbers I do before, I could + + align:start position:0% +rational numbers I do before, I could + + + align:start position:0% +rational numbers I do before, I could +say, "Oh, well, gee, a segment really is + + align:start position:0% +say, "Oh, well, gee, a segment really is + + + align:start position:0% +say, "Oh, well, gee, a segment really is +a pair of pairs." And the uh the + + align:start position:0% +a pair of pairs." And the uh the + + + align:start position:0% +a pair of pairs." And the uh the +xcoordinate of the first end point of + + align:start position:0% +xcoordinate of the first end point of + + + align:start position:0% +xcoordinate of the first end point of +the segment really is the well, what is + + align:start position:0% +the segment really is the well, what is + + + align:start position:0% +the segment really is the well, what is +it? It's the car + + align:start position:0% +it? It's the car + + + align:start position:0% +it? It's the car +of the car of the segment. So, I could + + align:start position:0% +of the car of the segment. So, I could + + + align:start position:0% +of the car of the segment. So, I could +perfectly well go and redefine length. I + + align:start position:0% +perfectly well go and redefine length. I + + + align:start position:0% +perfectly well go and redefine length. I +could say define + + align:start position:0% + + + + align:start position:0% + +the length + + align:start position:0% + + + + align:start position:0% + +of some segment s + + align:start position:0% +of some segment s + + + align:start position:0% +of some segment s +and I could start off writing something + + align:start position:0% +and I could start off writing something + + + align:start position:0% +and I could start off writing something +like well we well let + + align:start position:0% +like well we well let + + + align:start position:0% +like well we well let +dx + + align:start position:0% +dx + + + align:start position:0% +dx +be well what's got be it's got to be the + + align:start position:0% +be well what's got be it's got to be the + + + align:start position:0% +be well what's got be it's got to be the +difference of the two coordinates so + + align:start position:0% +difference of the two coordinates so + + + align:start position:0% +difference of the two coordinates so +that's the difference of the first one + + align:start position:0% +that's the difference of the first one + + + align:start position:0% +that's the difference of the first one +is the car + + align:start position:0% +is the car + + + align:start position:0% +is the car +of + + align:start position:0% +of + + + align:start position:0% +of +the car of s + + align:start position:0% +the car of s + + + align:start position:0% +the car of s +subtracted from The X the first one the + + align:start position:0% +subtracted from The X the first one the + + + align:start position:0% +subtracted from The X the first one the +car of the other half of it the cooter + + align:start position:0% +car of the other half of it the cooter + + + align:start position:0% +car of the other half of it the cooter +of S + + align:start position:0% + + + + align:start position:0% + +right and then dy would be + + align:start position:0% +right and then dy would be + + + align:start position:0% +right and then dy would be +well let's see it' be I'd get the + + align:start position:0% +well let's see it' be I'd get the + + + align:start position:0% +well let's see it' be I'd get the +ycoordinate so it' be the difference of + + align:start position:0% +ycoordinate so it' be the difference of + + + align:start position:0% +ycoordinate so it' be the difference of +the cooter + + align:start position:0% +the cooter + + + align:start position:0% +the cooter +of the car of S and the cter + + align:start position:0% +of the car of S and the cter + + + align:start position:0% +of the car of S and the cter +of the cter of this + + align:start position:0% +of the cter of this + + + align:start position:0% +of the cter of this +sort of go on. + + align:start position:0% +sort of go on. + + + align:start position:0% +sort of go on. +You can see that's that's much harder to + + align:start position:0% +You can see that's that's much harder to + + + align:start position:0% +You can see that's that's much harder to +read than the program I had before. But + + align:start position:0% +read than the program I had before. But + + + align:start position:0% +read than the program I had before. But +uh but worse than that, I mean suppose + + align:start position:0% +uh but worse than that, I mean suppose + + + align:start position:0% +uh but worse than that, I mean suppose +you'd gone and implemented length. + + align:start position:0% +you'd gone and implemented length. + + + align:start position:0% +you'd gone and implemented length. +You come + + align:start position:0% +You come + + + align:start position:0% +You come +and then the next day George comes to + + align:start position:0% +and then the next day George comes to + + + align:start position:0% +and then the next day George comes to +you and said, "I'm sorry, I changed my + + align:start position:0% +you and said, "I'm sorry, I changed my + + + align:start position:0% +you and said, "I'm sorry, I changed my +mind. I want to write points with the + + align:start position:0% +mind. I want to write points with the + + + align:start position:0% +mind. I want to write points with the +with the x coordinate first." So you + + align:start position:0% +with the x coordinate first." So you + + + align:start position:0% +with the x coordinate first." So you +come back and you stare at this code and + + align:start position:0% +come back and you stare at this code and + + + align:start position:0% +come back and you stare at this code and +say, "Oh, gee, what was that? That was + + align:start position:0% +say, "Oh, gee, what was that? That was + + + align:start position:0% +say, "Oh, gee, what was that? That was +the + + align:start position:0% +the + + + align:start position:0% +the +oh the car. So I have to change this to + + align:start position:0% +oh the car. So I have to change this to + + + align:start position:0% +oh the car. So I have to change this to +cter + + align:start position:0% +cter + + + align:start position:0% +cter +and uh this is cooter + + align:start position:0% +and uh this is cooter + + + align:start position:0% +and uh this is cooter +and this now has to be car + + align:start position:0% +and this now has to be car + + + align:start position:0% +and this now has to be car +and this has to be car + + align:start position:0% +and this has to be car + + + align:start position:0% +and this has to be car +and you sort of do that and then the + + align:start position:0% +and you sort of do that and then the + + + align:start position:0% +and you sort of do that and then the +next day George comes back and says + + align:start position:0% +next day George comes back and says + + + align:start position:0% +next day George comes back and says +sorry uh + + align:start position:0% +sorry uh + + + align:start position:0% +sorry uh +the guys designing the display would + + align:start position:0% +the guys designing the display would + + + align:start position:0% +the guys designing the display would +like you know would like lines to be + + align:start position:0% +like you know would like lines to be + + + align:start position:0% +like you know would like lines to be +painted in the opposite direction. So I + + align:start position:0% +painted in the opposite direction. So I + + + align:start position:0% +painted in the opposite direction. So I +have to write the end point first in the + + align:start position:0% +have to write the end point first in the + + + align:start position:0% +have to write the end point first in the +order and then you come back and you + + align:start position:0% +order and then you come back and you + + + align:start position:0% +order and then you come back and you +stare at this code and say gee what was + + align:start position:0% +stare at this code and say gee what was + + + align:start position:0% +stare at this code and say gee what was +it you know what was it talking about? + + align:start position:0% +it you know what was it talking about? + + + align:start position:0% +it you know what was it talking about? +Oh yeah well I got to change this one to + + align:start position:0% +Oh yeah well I got to change this one to + + + align:start position:0% +Oh yeah well I got to change this one to +cter and this one becomes car and this + + align:start position:0% +cter and this one becomes car and this + + + align:start position:0% +cter and this one becomes car and this +one becomes car and this becomes critter + + align:start position:0% +one becomes car and this becomes critter + + + align:start position:0% +one becomes car and this becomes critter +and you go off and do that and then the + + align:start position:0% +and you go off and do that and then the + + + align:start position:0% +and you go off and do that and then the +next day George comes back to you. I'm + + align:start position:0% +next day George comes back to you. I'm + + + align:start position:0% +next day George comes back to you. I'm +sorry what I really meant is that the + + align:start position:0% +sorry what I really meant is that the + + + align:start position:0% +sorry what I really meant is that the +segments always have to go be painted + + align:start position:0% +segments always have to go be painted + + + align:start position:0% +segments always have to go be painted +from left to right on the screen and + + align:start position:0% +from left to right on the screen and + + + align:start position:0% +from left to right on the screen and +then you sort of you know it's clear you + + align:start position:0% +then you sort of you know it's clear you + + + align:start position:0% +then you sort of you know it's clear you +just go and punch George in the mouth at + + align:start position:0% +just go and punch George in the mouth at + + + align:start position:0% +just go and punch George in the mouth at +that point. But uh + + align:start position:0% +that point. But uh + + + align:start position:0% +that point. But uh +right but you see as soon as we have you + + align:start position:0% +right but you see as soon as we have you + + + align:start position:0% +right but you see as soon as we have you +know a 10 layer system you see how that + + align:start position:0% +know a 10 layer system you see how that + + + align:start position:0% +know a 10 layer system you see how that +complexity immediately builds up to the + + align:start position:0% +complexity immediately builds up to the + + + align:start position:0% +complexity immediately builds up to the +point where where even something like + + align:start position:0% +point where where even something like + + + align:start position:0% +point where where even something like +this gets out of control. + + align:start position:0% +this gets out of control. + + + align:start position:0% +this gets out of control. +Right? So again the way we've gotten out + + align:start position:0% +Right? So again the way we've gotten out + + + align:start position:0% +Right? So again the way we've gotten out +of that is we've named that spirit. See, + + align:start position:0% +of that is we've named that spirit. See, + + + align:start position:0% +of that is we've named that spirit. See, +we've built we've built a system where + + align:start position:0% +we've built we've built a system where + + + align:start position:0% +we've built we've built a system where +there is a thing which is the + + align:start position:0% +there is a thing which is the + + + align:start position:0% +there is a thing which is the +representation choice for how you're + + align:start position:0% +representation choice for how you're + + + align:start position:0% +representation choice for how you're +going to talk about vectors and choices + + align:start position:0% +going to talk about vectors and choices + + + align:start position:0% +going to talk about vectors and choices +about that representation are localized + + align:start position:0% +about that representation are localized + + + align:start position:0% +about that representation are localized +right there. They don't have their guts + + align:start position:0% +right there. They don't have their guts + + + align:start position:0% +right there. They don't have their guts +spilling over into things like how you + + align:start position:0% +spilling over into things like how you + + + align:start position:0% +spilling over into things like how you +compute the length or how you compute + + align:start position:0% +compute the length or how you compute + + + align:start position:0% +compute the length or how you compute +the midpoint. + + align:start position:0% +the midpoint. + + + align:start position:0% +the midpoint. +Right? And that's the real that's the + + align:start position:0% +Right? And that's the real that's the + + + align:start position:0% +Right? And that's the real that's the +real power of this system. + + align:start position:0% +real power of this system. + + + align:start position:0% +real power of this system. +Okay? We're explicit about them so that + + align:start position:0% +Okay? We're explicit about them so that + + + align:start position:0% +Okay? We're explicit about them so that +we have control over them. + + align:start position:0% +we have control over them. + + + align:start position:0% +we have control over them. +Great questions. What happens in the + + align:start position:0% +Great questions. What happens in the + + + align:start position:0% +Great questions. What happens in the +case where you're you don't want to be + + align:start position:0% +case where you're you don't want to be + + + align:start position:0% +case where you're you don't want to be +treating objects in terms of pairs for + + align:start position:0% +treating objects in terms of pairs for + + + align:start position:0% +treating objects in terms of pairs for +instance that in three-dimensional space + + align:start position:0% +instance that in three-dimensional space + + + align:start position:0% +instance that in three-dimensional space +you'd have three coordinates or even in + + align:start position:0% +you'd have three coordinates or even in + + + align:start position:0% +you'd have three coordinates or even in +the case where you have n dimensional + + align:start position:0% +the case where you have n dimensional + + + align:start position:0% +the case where you have n dimensional +space + + align:start position:0% +space + + + align:start position:0% +space +right what happens + + align:start position:0% +right what happens + + + align:start position:0% +right what happens +okay well this is this is a preview of + + align:start position:0% +okay well this is this is a preview of + + + align:start position:0% +okay well this is this is a preview of +what I'll say tomorrow but uh + + align:start position:0% +what I'll say tomorrow but uh + + + align:start position:0% +what I'll say tomorrow but uh +the point is once you have once you have + + align:start position:0% +the point is once you have once you have + + + align:start position:0% +the point is once you have once you have +two things you have as many things as + + align:start position:0% +two things you have as many things as + + + align:start position:0% +two things you have as many things as +you want right because if I want to make + + align:start position:0% +you want right because if I want to make + + + align:start position:0% +you want right because if I want to make +three things I could start making things + + align:start position:0% +three things I could start making things + + + align:start position:0% +three things I could start making things +like a pair + + align:start position:0% + + + + align:start position:0% + +whose first thing is one and whose + + align:start position:0% +whose first thing is one and whose + + + align:start position:0% +whose first thing is one and whose +second thing is another pair + + align:start position:0% + + + + align:start position:0% + +that say has two and three in it. + + align:start position:0% +that say has two and three in it. + + + align:start position:0% +that say has two and three in it. +So I wanted 100 things. I can nest them + + align:start position:0% +So I wanted 100 things. I can nest them + + + align:start position:0% +So I wanted 100 things. I can nest them +out of pairs. Here I made a pretty + + align:start position:0% +out of pairs. Here I made a pretty + + + align:start position:0% +out of pairs. Here I made a pretty +arbitrary decision about how to do it. + + align:start position:0% +arbitrary decision about how to do it. + + + align:start position:0% +arbitrary decision about how to do it. +And you can immediately see there are + + align:start position:0% +And you can immediately see there are + + + align:start position:0% +And you can immediately see there are +lots of ways to do that. We'll start + + align:start position:0% +lots of ways to do that. We'll start + + + align:start position:0% +lots of ways to do that. We'll start +talking about next time are conventions + + align:start position:0% +talking about next time are conventions + + + align:start position:0% +talking about next time are conventions +for how to do things like that. + + align:start position:0% +for how to do things like that. + + + align:start position:0% +for how to do things like that. +But notice that what this really depends + + align:start position:0% +But notice that what this really depends + + + align:start position:0% +But notice that what this really depends +on is I can make pairs of pairs. + + align:start position:0% +on is I can make pairs of pairs. + + + align:start position:0% +on is I can make pairs of pairs. +If all I could do was make pairs of + + align:start position:0% +If all I could do was make pairs of + + + align:start position:0% +If all I could do was make pairs of +numbers, I'd be stuck. + + align:start position:0% + + + + align:start position:0% + +Okay, + + align:start position:0% +Okay, + + + align:start position:0% +Okay, +let's break. + + align:start position:0% +let's break. + + + align:start position:0% +let's break. +[Music] + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +All right. Well, we've just gone off and + + align:start position:0% +All right. Well, we've just gone off and + + + align:start position:0% +All right. Well, we've just gone off and +done + + align:start position:0% +done + + + align:start position:0% +done +a couple of simple examples of data + + align:start position:0% +a couple of simple examples of data + + + align:start position:0% +a couple of simple examples of data +abstraction. + + align:start position:0% +abstraction. + + + align:start position:0% +abstraction. +Now, I'm going to do something more + + align:start position:0% +Now, I'm going to do something more + + + align:start position:0% +Now, I'm going to do something more +complicated. We're going to talk about + + align:start position:0% +complicated. We're going to talk about + + + align:start position:0% +complicated. We're going to talk about +what it means. And this will be harder + + align:start position:0% +what it means. And this will be harder + + + align:start position:0% +what it means. And this will be harder +because it's always It's always much + + align:start position:0% +because it's always It's always much + + + align:start position:0% +because it's always It's always much +harder to in computer programming to + + align:start position:0% +harder to in computer programming to + + + align:start position:0% +harder to in computer programming to +talk about what something means than to + + align:start position:0% +talk about what something means than to + + + align:start position:0% +talk about what something means than to +go off and do it. But uh let's go back + + align:start position:0% +go off and do it. But uh let's go back + + + align:start position:0% +go off and do it. But uh let's go back +to almost the very beginning. Let's go + + align:start position:0% +to almost the very beginning. Let's go + + + align:start position:0% +to almost the very beginning. Let's go +back to the point where I said we just + + align:start position:0% +back to the point where I said we just + + + align:start position:0% +back to the point where I said we just +assumed that there were procedures + + align:start position:0% +assumed that there were procedures + + + align:start position:0% +assumed that there were procedures +make + + align:start position:0% +make + + + align:start position:0% +make +and numer + + align:start position:0% + + + + align:start position:0% + +and denom. + + align:start position:0% +and denom. + + + align:start position:0% +and denom. +Let's go back to where we had those at + + align:start position:0% +Let's go back to where we had those at + + + align:start position:0% +Let's go back to where we had those at +the very beginning constructors and + + align:start position:0% +the very beginning constructors and + + + align:start position:0% +the very beginning constructors and +selectors and went off and defined the + + align:start position:0% +selectors and went off and defined the + + + align:start position:0% +selectors and went off and defined the +rational number arithmetic. And I + + align:start position:0% +rational number arithmetic. And I + + + align:start position:0% +rational number arithmetic. And I +remember I said at that point we were + + align:start position:0% +remember I said at that point we were + + + align:start position:0% +remember I said at that point we were +sort of done except for George. + + align:start position:0% +sort of done except for George. + + + align:start position:0% +sort of done except for George. +Well, but what is it that we'd actually + + align:start position:0% +Well, but what is it that we'd actually + + + align:start position:0% +Well, but what is it that we'd actually +done at that point? What was it that was + + align:start position:0% +done at that point? What was it that was + + + align:start position:0% +done at that point? What was it that was +done? + + align:start position:0% +done? + + + align:start position:0% +done? +Well, what I want to say is what was + + align:start position:0% +Well, what I want to say is what was + + + align:start position:0% +Well, what I want to say is what was +done after we'd implemented the + + align:start position:0% +done after we'd implemented the + + + align:start position:0% +done after we'd implemented the +operations in terms of these was that we + + align:start position:0% +operations in terms of these was that we + + + align:start position:0% +operations in terms of these was that we +had defined our rational number + + align:start position:0% +had defined our rational number + + + align:start position:0% +had defined our rational number +representation in terms of abstract + + align:start position:0% +representation in terms of abstract + + + align:start position:0% +representation in terms of abstract +data. + + align:start position:0% + + + + align:start position:0% + +What do I mean by abstract data? + + align:start position:0% +What do I mean by abstract data? + + + align:start position:0% +What do I mean by abstract data? +Well, the idea is that + + align:start position:0% +Well, the idea is that + + + align:start position:0% +Well, the idea is that +at that point when we had our plus rat + + align:start position:0% +at that point when we had our plus rat + + + align:start position:0% +at that point when we had our plus rat +and our star rat + + align:start position:0% +and our star rat + + + align:start position:0% +and our star rat +that any implementation of make rat and + + align:start position:0% +that any implementation of make rat and + + + align:start position:0% +that any implementation of make rat and +numerator and denominator + + align:start position:0% +numerator and denominator + + + align:start position:0% +numerator and denominator +that George supplied us with + + align:start position:0% +that George supplied us with + + + align:start position:0% +that George supplied us with +could be the basis for a rational number + + align:start position:0% +could be the basis for a rational number + + + align:start position:0% +could be the basis for a rational number +representation like it wasn't our + + align:start position:0% +representation like it wasn't our + + + align:start position:0% +representation like it wasn't our +concern where you where you uh divide it + + align:start position:0% +concern where you where you uh divide it + + + align:start position:0% +concern where you where you uh divide it +through to get the greatest common + + align:start position:0% +through to get the greatest common + + + align:start position:0% +through to get the greatest common +denominator or any of that. + + align:start position:0% +denominator or any of that. + + + align:start position:0% +denominator or any of that. +Right? So the idea is that what we built + + align:start position:0% +Right? So the idea is that what we built + + + align:start position:0% +Right? So the idea is that what we built +is a rational arithmetic system that + + align:start position:0% +is a rational arithmetic system that + + + align:start position:0% +is a rational arithmetic system that +would sit on top of any representation. + + align:start position:0% +would sit on top of any representation. + + + align:start position:0% +would sit on top of any representation. +But what do I mean by any + + align:start position:0% +But what do I mean by any + + + align:start position:0% +But what do I mean by any +representation? + + align:start position:0% +representation? + + + align:start position:0% +representation? +I mean certainly it can't be the case + + align:start position:0% +I mean certainly it can't be the case + + + align:start position:0% +I mean certainly it can't be the case +that all I mean is George can reach in a + + align:start position:0% +that all I mean is George can reach in a + + + align:start position:0% +that all I mean is George can reach in a +bag and pull out three arbitrary + + align:start position:0% +bag and pull out three arbitrary + + + align:start position:0% +bag and pull out three arbitrary +procedures + + align:start position:0% +procedures + + + align:start position:0% +procedures +and say well fine now you now that's the + + align:start position:0% +and say well fine now you now that's the + + + align:start position:0% +and say well fine now you now that's the +implementation right that can't be what + + align:start position:0% +implementation right that can't be what + + + align:start position:0% +implementation right that can't be what +I mean right what I've got to mean is + + align:start position:0% +I mean right what I've got to mean is + + + align:start position:0% +I mean right what I've got to mean is +that there's + + align:start position:0% +that there's + + + align:start position:0% +that there's +some way of saying whether + + align:start position:0% +some way of saying whether + + + align:start position:0% +some way of saying whether +three procedures are going to be + + align:start position:0% +three procedures are going to be + + + align:start position:0% +three procedures are going to be +suitable as a basis for rational number + + align:start position:0% +suitable as a basis for rational number + + + align:start position:0% +suitable as a basis for rational number +representation if we if we think about + + align:start position:0% +representation if we if we think about + + + align:start position:0% +representation if we if we think about +it what's suitable might mean is is if I + + align:start position:0% +it what's suitable might mean is is if I + + + align:start position:0% +it what's suitable might mean is is if I +have to assume something like this. So I + + align:start position:0% +have to assume something like this. So I + + + align:start position:0% +have to assume something like this. So I +have to say that if + + align:start position:0% +have to say that if + + + align:start position:0% +have to say that if +X is the result of + + align:start position:0% +X is the result of + + + align:start position:0% +X is the result of +say doing make rat + + align:start position:0% + + + + align:start position:0% + +of N and D + + align:start position:0% + + + + align:start position:0% + +then + + align:start position:0% + + + + align:start position:0% + +the numerator + + align:start position:0% +the numerator + + + align:start position:0% +the numerator +of X + + align:start position:0% +of X + + + align:start position:0% +of X +divided by the denominator of X + + align:start position:0% + + + + align:start position:0% + +is equal to N /d D. + + align:start position:0% +is equal to N /d D. + + + align:start position:0% +is equal to N /d D. +See what that is is that's George's + + align:start position:0% +See what that is is that's George's + + + align:start position:0% +See what that is is that's George's +contract. + + align:start position:0% +contract. + + + align:start position:0% +contract. +What we mean by writing a contract for + + align:start position:0% +What we mean by writing a contract for + + + align:start position:0% +What we mean by writing a contract for +rational numbers, if you think about it, + + align:start position:0% +rational numbers, if you think about it, + + + align:start position:0% +rational numbers, if you think about it, +this is the right thing. And the two the + + align:start position:0% +this is the right thing. And the two the + + + align:start position:0% +this is the right thing. And the two the +two ones we showed do do the right + + align:start position:0% +two ones we showed do do the right + + + align:start position:0% +two ones we showed do do the right +thing. You see, if I'm taking out + + align:start position:0% +thing. You see, if I'm taking out + + + align:start position:0% +thing. You see, if I'm taking out +greatest common divisors, + + align:start position:0% +greatest common divisors, + + + align:start position:0% +greatest common divisors, +doesn't matter whether I take them out + + align:start position:0% +doesn't matter whether I take them out + + + align:start position:0% +doesn't matter whether I take them out +or not or the place where I take them + + align:start position:0% +or not or the place where I take them + + + align:start position:0% +or not or the place where I take them +out because the idea is I'm going to + + align:start position:0% +out because the idea is I'm going to + + + align:start position:0% +out because the idea is I'm going to +divide through. + + align:start position:0% +divide through. + + + align:start position:0% +divide through. +But see, this is George's contract. So, + + align:start position:0% +But see, this is George's contract. So, + + + align:start position:0% +But see, this is George's contract. So, +what we really say to George is what + + align:start position:0% +what we really say to George is what + + + align:start position:0% +what we really say to George is what +your your business is to go off and find + + align:start position:0% +your your business is to go off and find + + + align:start position:0% +your your business is to go off and find +us three procedures make numerator and + + align:start position:0% +us three procedures make numerator and + + + align:start position:0% +us three procedures make numerator and +denominator that fulfill this contract + + align:start position:0% +denominator that fulfill this contract + + + align:start position:0% +denominator that fulfill this contract +for any choice of N and D. And that's + + align:start position:0% +for any choice of N and D. And that's + + + align:start position:0% +for any choice of N and D. And that's +what we mean by we can use that as the + + align:start position:0% +what we mean by we can use that as the + + + align:start position:0% +what we mean by we can use that as the +basis for a rational number + + align:start position:0% +basis for a rational number + + + align:start position:0% +basis for a rational number +representation. + + align:start position:0% +representation. + + + align:start position:0% +representation. +And other than that, it fulfills this + + align:start position:0% +And other than that, it fulfills this + + + align:start position:0% +And other than that, it fulfills this +contract. We don't care how he does it. + + align:start position:0% +contract. We don't care how he does it. + + + align:start position:0% +contract. We don't care how he does it. +It's not our business. It's below the + + align:start position:0% +It's not our business. It's below the + + + align:start position:0% +It's not our business. It's below the +layer of abstraction. + + align:start position:0% + + + + align:start position:0% + +In fact, if we want to say what is a + + align:start position:0% +In fact, if we want to say what is a + + + align:start position:0% +In fact, if we want to say what is a +rational number really, + + align:start position:0% +rational number really, + + + align:start position:0% +rational number really, +see what's it really without having to + + align:start position:0% +see what's it really without having to + + + align:start position:0% +see what's it really without having to +talk about going below the layer of + + align:start position:0% +talk about going below the layer of + + + align:start position:0% +talk about going below the layer of +abstraction. What we're forced into + + align:start position:0% +abstraction. What we're forced into + + + align:start position:0% +abstraction. What we're forced into +saying is a rational number really + + align:start position:0% +saying is a rational number really + + + align:start position:0% +saying is a rational number really +is sort of this axiom is three + + align:start position:0% +is sort of this axiom is three + + + align:start position:0% +is sort of this axiom is three +procedures make numerator and + + align:start position:0% +procedures make numerator and + + + align:start position:0% +procedures make numerator and +denominator that satisfy this axiom. + + align:start position:0% +denominator that satisfy this axiom. + + + align:start position:0% +denominator that satisfy this axiom. +in some in some sense abstractly that's + + align:start position:0% +in some in some sense abstractly that's + + + align:start position:0% +in some in some sense abstractly that's +what a rational number is really right + + align:start position:0% +what a rational number is really right + + + align:start position:0% +what a rational number is really right +so we that's + + align:start position:0% +so we that's + + + align:start position:0% +so we that's +that's sort of easy that's sort of easy + + align:start position:0% +that's sort of easy that's sort of easy + + + align:start position:0% +that's sort of easy that's sort of easy +words to listen to because what you have + + align:start position:0% +words to listen to because what you have + + + align:start position:0% +words to listen to because what you have +in your head of course is well for all + + align:start position:0% +in your head of course is well for all + + + align:start position:0% +in your head of course is well for all +this thing about saying that's what a + + align:start position:0% +this thing about saying that's what a + + + align:start position:0% +this thing about saying that's what a +rational number is really you actually + + align:start position:0% +rational number is really you actually + + + align:start position:0% +rational number is really you actually +just saw that we built rational numbers + + align:start position:0% + + + + align:start position:0% + +what we really did is we built rational + + align:start position:0% +what we really did is we built rational + + + align:start position:0% +what we really did is we built rational +numbers + + align:start position:0% + + + + align:start position:0% + +on top of pairs. + + align:start position:0% + + + + align:start position:0% + +So for all I'm saying abstractly, we can + + align:start position:0% +So for all I'm saying abstractly, we can + + + align:start position:0% +So for all I'm saying abstractly, we can +say a rational number really is just + + align:start position:0% +say a rational number really is just + + + align:start position:0% +say a rational number really is just +this axiom. + + align:start position:0% +this axiom. + + + align:start position:0% +this axiom. +You can listen to that comfortably + + align:start position:0% +You can listen to that comfortably + + + align:start position:0% +You can listen to that comfortably +because you're saying, "Well, yeah, but + + align:start position:0% +because you're saying, "Well, yeah, but + + + align:start position:0% +because you're saying, "Well, yeah, but +really it's actually pairs and I'm just + + align:start position:0% +really it's actually pairs and I'm just + + + align:start position:0% +really it's actually pairs and I'm just +annoying you by trying to be abstract." + + align:start position:0% +annoying you by trying to be abstract." + + + align:start position:0% +annoying you by trying to be abstract." +Well, let me as an antidote for that, + + align:start position:0% +Well, let me as an antidote for that, + + + align:start position:0% +Well, let me as an antidote for that, +let me do something that I think is + + align:start position:0% +let me do something that I think is + + + align:start position:0% +let me do something that I think is +really going to terrify you and is + + align:start position:0% +really going to terrify you and is + + + align:start position:0% +really going to terrify you and is +really going to bring you, you know, + + align:start position:0% +really going to bring you, you know, + + + align:start position:0% +really going to bring you, you know, +face to face with the the sort of uh + + align:start position:0% +face to face with the the sort of uh + + + align:start position:0% +face to face with the the sort of uh +existential reality of this abstraction + + align:start position:0% +existential reality of this abstraction + + + align:start position:0% +existential reality of this abstraction +that we're talking about. And what I'm + + align:start position:0% +that we're talking about. And what I'm + + + align:start position:0% +that we're talking about. And what I'm +going to talk about is what are pairs + + align:start position:0% +going to talk about is what are pairs + + + align:start position:0% +going to talk about is what are pairs +really? + + align:start position:0% +really? + + + align:start position:0% +really? +See, what did I tell you about pairs? + + align:start position:0% +See, what did I tell you about pairs? + + + align:start position:0% +See, what did I tell you about pairs? +I tricked you, right? I said that list + + align:start position:0% +I tricked you, right? I said that list + + + align:start position:0% +I tricked you, right? I said that list +well list has this primitive called con + + align:start position:0% +well list has this primitive called con + + + align:start position:0% +well list has this primitive called con +that builds pairs. But what did I really + + align:start position:0% +that builds pairs. But what did I really + + + align:start position:0% +that builds pairs. But what did I really +tell you about them? If you go back and + + align:start position:0% +tell you about them? If you go back and + + + align:start position:0% +tell you about them? If you go back and +said, let's look on this slide, all I + + align:start position:0% +said, let's look on this slide, all I + + + align:start position:0% +said, let's look on this slide, all I +really told you about pairs is that + + align:start position:0% +really told you about pairs is that + + + align:start position:0% +really told you about pairs is that +there happens to be this properties, + + align:start position:0% +there happens to be this properties, + + + align:start position:0% +there happens to be this properties, +these properties of K, car, and CERT. + + align:start position:0% +these properties of K, car, and CERT. + + + align:start position:0% +these properties of K, car, and CERT. +And all I really said about pairs is + + align:start position:0% +And all I really said about pairs is + + + align:start position:0% +And all I really said about pairs is +that there's a thing called cons and a + + align:start position:0% +that there's a thing called cons and a + + + align:start position:0% +that there's a thing called cons and a +thing called car and a thing called + + align:start position:0% +thing called car and a thing called + + + align:start position:0% +thing called car and a thing called +curter. + + align:start position:0% +curter. + + + align:start position:0% +curter. +And it is the case that if I build const + + align:start position:0% +And it is the case that if I build const + + + align:start position:0% +And it is the case that if I build const +of xy and take car of it, I get x. + + align:start position:0% +of xy and take car of it, I get x. + + + align:start position:0% +of xy and take car of it, I get x. +And if I build cter if I build concept + + align:start position:0% +And if I build cter if I build concept + + + align:start position:0% +And if I build cter if I build concept +xy and get cer of it I get y + + align:start position:0% +xy and get cer of it I get y + + + align:start position:0% +xy and get cer of it I get y +and that + + align:start position:0% +and that + + + align:start position:0% +and that +right even though I even though I lulled + + align:start position:0% +right even though I even though I lulled + + + align:start position:0% +right even though I even though I lulled +you into thinking that there's something + + align:start position:0% +you into thinking that there's something + + + align:start position:0% +you into thinking that there's something +in lisp that does that so you pretended + + align:start position:0% +in lisp that does that so you pretended + + + align:start position:0% +in lisp that does that so you pretended +you knew what it was in fact I didn't + + align:start position:0% +you knew what it was in fact I didn't + + + align:start position:0% +you knew what it was in fact I didn't +tell you any more about pairs than this + + align:start position:0% +tell you any more about pairs than this + + + align:start position:0% +tell you any more about pairs than this +tells you about rational numbers it's + + align:start position:0% +tells you about rational numbers it's + + + align:start position:0% +tells you about rational numbers it's +just some axiom for pairs + + align:start position:0% + + + + align:start position:0% + +well + + align:start position:0% +well + + + align:start position:0% +well +to drive that home let me really scare + + align:start position:0% + + + + align:start position:0% + +and show you what we might build pairs + + align:start position:0% +and show you what we might build pairs + + + align:start position:0% +and show you what we might build pairs +in terms of + + align:start position:0% +in terms of + + + align:start position:0% +in terms of +what you're going to see is that we can + + align:start position:0% +what you're going to see is that we can + + + align:start position:0% +what you're going to see is that we can +build right rational numbers and line + + align:start position:0% +build right rational numbers and line + + + align:start position:0% +build right rational numbers and line +segments and vectors and all of this + + align:start position:0% +segments and vectors and all of this + + + align:start position:0% +segments and vectors and all of this +stuff in terms of pairs. And we're going + + align:start position:0% +stuff in terms of pairs. And we're going + + + align:start position:0% +stuff in terms of pairs. And we're going +to see below here that pairs can be + + align:start position:0% +to see below here that pairs can be + + + align:start position:0% +to see below here that pairs can be +built out of nothing at all. + + align:start position:0% +built out of nothing at all. + + + align:start position:0% +built out of nothing at all. +Right? Pure abstraction. So what let me + + align:start position:0% +Right? Pure abstraction. So what let me + + + align:start position:0% +Right? Pure abstraction. So what let me +show you on this slide + + align:start position:0% +show you on this slide + + + align:start position:0% +show you on this slide +an implementation of constar encoder + + align:start position:0% + + + + align:start position:0% + +and we'll look at it again in a second + + align:start position:0% +and we'll look at it again in a second + + + align:start position:0% +and we'll look at it again in a second +but notice that their procedure + + align:start position:0% +but notice that their procedure + + + align:start position:0% +but notice that their procedure +definition of const + + align:start position:0% +definition of const + + + align:start position:0% +definition of const +you don't see any data in there what you + + align:start position:0% +you don't see any data in there what you + + + align:start position:0% +you don't see any data in there what you +see is + + align:start position:0% +see is + + + align:start position:0% +see is +is a lambda + + align:start position:0% +is a lambda + + + align:start position:0% +is a lambda +right con so conce here is going to + + align:start position:0% +right con so conce here is going to + + + align:start position:0% +right con so conce here is going to +return is a procedure that returns a + + align:start position:0% +return is a procedure that returns a + + + align:start position:0% +return is a procedure that returns a +procedure just like uh average n + + align:start position:0% +procedure just like uh average n + + + align:start position:0% +procedure just like uh average n +con a and b returns a procedure + + align:start position:0% +con a and b returns a procedure + + + align:start position:0% +con a and b returns a procedure +of an argument called pick + + align:start position:0% +of an argument called pick + + + align:start position:0% +of an argument called pick +and it says if p is equal to one I'm + + align:start position:0% +and it says if p is equal to one I'm + + + align:start position:0% +and it says if p is equal to one I'm +going to return a and if p is equal to + + align:start position:0% +going to return a and if p is equal to + + + align:start position:0% +going to return a and if p is equal to +two I'm going to return b and that's + + align:start position:0% +two I'm going to return b and that's + + + align:start position:0% +two I'm going to return b and that's +what con is going to be + + align:start position:0% + + + + align:start position:0% + +car of + + align:start position:0% +car of + + + align:start position:0% +car of +a thing x car of a pair x is going to be + + align:start position:0% +a thing x car of a pair x is going to be + + + align:start position:0% +a thing x car of a pair x is going to be +x applied to one and notice that makes + + align:start position:0% +x applied to one and notice that makes + + + align:start position:0% +x applied to one and notice that makes +sense. You may not understand why or how + + align:start position:0% +sense. You may not understand why or how + + + align:start position:0% +sense. You may not understand why or how +I'm doing such a thing, but at least it + + align:start position:0% +I'm doing such a thing, but at least it + + + align:start position:0% +I'm doing such a thing, but at least it +makes sense because the thing + + align:start position:0% +makes sense because the thing + + + align:start position:0% +makes sense because the thing +constructed by con is a procedure and + + align:start position:0% +constructed by con is a procedure and + + + align:start position:0% +constructed by con is a procedure and +car applies that to one + + align:start position:0% +car applies that to one + + + align:start position:0% +car applies that to one +and similarly cooter applies that thing + + align:start position:0% +and similarly cooter applies that thing + + + align:start position:0% +and similarly cooter applies that thing +to two. + + align:start position:0% +to two. + + + align:start position:0% +to two. +Okay, now I claim that this is a + + align:start position:0% +Okay, now I claim that this is a + + + align:start position:0% +Okay, now I claim that this is a +representation of concar and cter. And + + align:start position:0% +representation of concar and cter. And + + + align:start position:0% +representation of concar and cter. And +notice there's no data in it, right? + + align:start position:0% +notice there's no data in it, right? + + + align:start position:0% +notice there's no data in it, right? +It's built out of air. It's just + + align:start position:0% +It's built out of air. It's just + + + align:start position:0% +It's built out of air. It's just +procedures, + + align:start position:0% +procedures, + + + align:start position:0% +procedures, +right? There's no data objects at all in + + align:start position:0% +right? There's no data objects at all in + + + align:start position:0% +right? There's no data objects at all in +that representation. + + align:start position:0% +that representation. + + + align:start position:0% +that representation. +Well, what could that possibly mean, + + align:start position:0% +Well, what could that possibly mean, + + + align:start position:0% +Well, what could that possibly mean, +right? + + align:start position:0% +right? + + + align:start position:0% +right? +Well, if you really believe this stuff, + + align:start position:0% +Well, if you really believe this stuff, + + + align:start position:0% +Well, if you really believe this stuff, +then you have to believe that in order + + align:start position:0% +then you have to believe that in order + + + align:start position:0% +then you have to believe that in order +to show that that's a representation for + + align:start position:0% +to show that that's a representation for + + + align:start position:0% +to show that that's a representation for +K's current critter, all I have to do is + + align:start position:0% +K's current critter, all I have to do is + + + align:start position:0% +K's current critter, all I have to do is +show that it satisfies the axiom. See, + + align:start position:0% +show that it satisfies the axiom. See, + + + align:start position:0% +show that it satisfies the axiom. See, +all I should have to convince you of is + + align:start position:0% +all I should have to convince you of is + + + align:start position:0% +all I should have to convince you of is +for example that uh + + align:start position:0% +for example that uh + + + align:start position:0% +for example that uh +gee that car + + align:start position:0% +gee that car + + + align:start position:0% +gee that car +of cons of 37 and 49, + + align:start position:0% + + + + align:start position:0% + +right? Is 37, right? For arbitrary + + align:start position:0% +right? Is 37, right? For arbitrary + + + align:start position:0% +right? Is 37, right? For arbitrary +values of 37 and 49, right? See if I + + align:start position:0% +values of 37 and 49, right? See if I + + + align:start position:0% +values of 37 and 49, right? See if I +really can and could the same way, + + align:start position:0% +really can and could the same way, + + + align:start position:0% +really can and could the same way, +right? See, if I really can can + + align:start position:0% +right? See, if I really can can + + + align:start position:0% +right? See, if I really can can +demonstrate to you that that weird + + align:start position:0% +demonstrate to you that that weird + + + align:start position:0% +demonstrate to you that that weird +procedure definition in terms of air has + + align:start position:0% +procedure definition in terms of air has + + + align:start position:0% +procedure definition in terms of air has +the property that it satisfies this, + + align:start position:0% +the property that it satisfies this, + + + align:start position:0% +the property that it satisfies this, +then you just have to grant me that that + + align:start position:0% +then you just have to grant me that that + + + align:start position:0% +then you just have to grant me that that +is a rep that is a possible + + align:start position:0% +is a rep that is a possible + + + align:start position:0% +is a rep that is a possible +implementation of const which I can + + align:start position:0% +implementation of const which I can + + + align:start position:0% +implementation of const which I can +build everything else. Well, let's look + + align:start position:0% +build everything else. Well, let's look + + + align:start position:0% +build everything else. Well, let's look +at that. This will be practice in in the + + align:start position:0% +at that. This will be practice in in the + + + align:start position:0% +at that. This will be practice in in the +substitution model. How would I actually + + align:start position:0% + + + + align:start position:0% + +right how could we check this? So we + + align:start position:0% +right how could we check this? So we + + + align:start position:0% +right how could we check this? So we +sort of know how to do that. It's just + + align:start position:0% +sort of know how to do that. It's just + + + align:start position:0% +sort of know how to do that. It's just +the same substitution model, + + align:start position:0% +the same substitution model, + + + align:start position:0% +the same substitution model, +right? Let's let's look. We start out + + align:start position:0% +right? Let's let's look. We start out + + + align:start position:0% +right? Let's let's look. We start out +and we say what's car of con of 37 and + + align:start position:0% +and we say what's car of con of 37 and + + + align:start position:0% +and we say what's car of con of 37 and +49. + + align:start position:0% +49. + + + align:start position:0% +49. +What do we do? Conce is some procedure. + + align:start position:0% + + + + align:start position:0% + +Its value is cons was a procedure of a + + align:start position:0% +Its value is cons was a procedure of a + + + align:start position:0% +Its value is cons was a procedure of a +and b. The thing returned by k is its + + align:start position:0% +and b. The thing returned by k is its + + + align:start position:0% +and b. The thing returned by k is its +procedure body with 37 sub and 49 + + align:start position:0% +procedure body with 37 sub and 49 + + + align:start position:0% +procedure body with 37 sub and 49 +substituted for the parameters. namely + + align:start position:0% +substituted for the parameters. namely + + + align:start position:0% +substituted for the parameters. namely +37 substituted for a and 49 substituted + + align:start position:0% +37 substituted for a and 49 substituted + + + align:start position:0% +37 substituted for a and 49 substituted +for b. + + align:start position:0% +for b. + + + align:start position:0% +for b. +So this expression has the same meaning + + align:start position:0% +So this expression has the same meaning + + + align:start position:0% +So this expression has the same meaning +as this expression. And it's car of and + + align:start position:0% +as this expression. And it's car of and + + + align:start position:0% +as this expression. And it's car of and +the body of const was this thing that + + align:start position:0% +the body of const was this thing that + + + align:start position:0% +the body of const was this thing that +started with lambda + + align:start position:0% +started with lambda + + + align:start position:0% +started with lambda +and says so if p is equal to one where p + + align:start position:0% +and says so if p is equal to one where p + + + align:start position:0% +and says so if p is equal to one where p +is this other argument if p is equal to + + align:start position:0% +is this other argument if p is equal to + + + align:start position:0% +is this other argument if p is equal to +1 it's 37 that's where a was and if p is + + align:start position:0% +1 it's 37 that's where a was and if p is + + + align:start position:0% +1 it's 37 that's where a was and if p is +equal to two it's 49 + + align:start position:0% +equal to two it's 49 + + + align:start position:0% +equal to two it's 49 +right so that's the first step and I'm + + align:start position:0% +right so that's the first step and I'm + + + align:start position:0% +right so that's the first step and I'm +just going through mechanical + + align:start position:0% +just going through mechanical + + + align:start position:0% +just going through mechanical +substitution and remember at this point + + align:start position:0% +substitution and remember at this point + + + align:start position:0% +substitution and remember at this point +in the course if you're confused about + + align:start position:0% +in the course if you're confused about + + + align:start position:0% +in the course if you're confused about +what things mean go mechanically through + + align:start position:0% +what things mean go mechanically through + + + align:start position:0% +what things mean go mechanically through +the substitution model. Well, what does + + align:start position:0% +the substitution model. Well, what does + + + align:start position:0% +the substitution model. Well, what does +this reduced to? + + align:start position:0% +this reduced to? + + + align:start position:0% +this reduced to? +Carr said take your + + align:start position:0% +Carr said take your + + + align:start position:0% +Carr said take your +take your argument which in this case is + + align:start position:0% +take your argument which in this case is + + + align:start position:0% +take your argument which in this case is +this and apply it to one. That was the + + align:start position:0% +this and apply it to one. That was the + + + align:start position:0% +this and apply it to one. That was the +definition of car. So if I look at car + + align:start position:0% +definition of car. So if I look at car + + + align:start position:0% +definition of car. So if I look at car +if I do that the answer is well it's + + align:start position:0% +if I do that the answer is well it's + + + align:start position:0% +if I do that the answer is well it's +that argument. This was the argument to + + align:start position:0% +that argument. This was the argument to + + + align:start position:0% +that argument. This was the argument to +car applied to one. + + align:start position:0% + + + + align:start position:0% + +Well what does that mean? I take one and + + align:start position:0% +Well what does that mean? I take one and + + + align:start position:0% +Well what does that mean? I take one and +I substitute it in the body here for + + align:start position:0% +I substitute it in the body here for + + + align:start position:0% +I substitute it in the body here for +this value of pick which is the name of + + align:start position:0% +this value of pick which is the name of + + + align:start position:0% +this value of pick which is the name of +the argument and what do I get? Well, I + + align:start position:0% +the argument and what do I get? Well, I + + + align:start position:0% +the argument and what do I get? Well, I +get the thing that says if one equals to + + align:start position:0% +get the thing that says if one equals to + + + align:start position:0% +get the thing that says if one equals to +equals 1, it's 37 and if one equals 2, + + align:start position:0% +equals 1, it's 37 and if one equals 2, + + + align:start position:0% +equals 1, it's 37 and if one equals 2, +it's 49. So the answer is 37. And + + align:start position:0% +it's 49. So the answer is 37. And + + + align:start position:0% +it's 49. So the answer is 37. And +similarly, if I'd applied it if I'd + + align:start position:0% +similarly, if I'd applied it if I'd + + + align:start position:0% +similarly, if I'd applied it if I'd +taken cter that would apply it to two + + align:start position:0% +taken cter that would apply it to two + + + align:start position:0% +taken cter that would apply it to two +and I'd get 49. So you see what I've + + align:start position:0% +and I'd get 49. So you see what I've + + + align:start position:0% +and I'd get 49. So you see what I've +demonstrated is that that completely + + align:start position:0% +demonstrated is that that completely + + + align:start position:0% +demonstrated is that that completely +weird implementation of K's current + + align:start position:0% +weird implementation of K's current + + + align:start position:0% +weird implementation of K's current +satisfies the axioms. So it's a + + align:start position:0% +satisfies the axioms. So it's a + + + align:start position:0% +satisfies the axioms. So it's a +perfectly valid way of building in fact + + align:start position:0% +perfectly valid way of building in fact + + + align:start position:0% +perfectly valid way of building in fact +all of the data objects we're going to + + align:start position:0% +all of the data objects we're going to + + + align:start position:0% +all of the data objects we're going to +see in lisp. So they all if you like can + + align:start position:0% +see in lisp. So they all if you like can + + + align:start position:0% +see in lisp. So they all if you like can +be built on on sort of existential + + align:start position:0% +be built on on sort of existential + + + align:start position:0% +be built on on sort of existential +nothing and as far as you know that's + + align:start position:0% +nothing and as far as you know that's + + + align:start position:0% +nothing and as far as you know that's +how it works. + + align:start position:0% +how it works. + + + align:start position:0% +how it works. +You couldn't tell if all you're ever + + align:start position:0% +You couldn't tell if all you're ever + + + align:start position:0% +You couldn't tell if all you're ever +going to do with pairs is construct them + + align:start position:0% +going to do with pairs is construct them + + + align:start position:0% +going to do with pairs is construct them +with consonant look at them with car and + + align:start position:0% +with consonant look at them with car and + + + align:start position:0% +with consonant look at them with car and +curter. You couldn't possibly tell how + + align:start position:0% +curter. You couldn't possibly tell how + + + align:start position:0% +curter. You couldn't possibly tell how +this thing works. + + align:start position:0% +this thing works. + + + align:start position:0% +this thing works. +Now it might give you a sort of warm + + align:start position:0% +Now it might give you a sort of warm + + + align:start position:0% +Now it might give you a sort of warm +feeling inside if I say well yeah in + + align:start position:0% +feeling inside if I say well yeah in + + + align:start position:0% +feeling inside if I say well yeah in +fact for various reasons there happens + + align:start position:0% +fact for various reasons there happens + + + align:start position:0% +fact for various reasons there happens +to be a primitive called conscar and + + align:start position:0% +to be a primitive called conscar and + + + align:start position:0% +to be a primitive called conscar and +citterter and you know if it's too scary + + align:start position:0% +citterter and you know if it's too scary + + + align:start position:0% +citterter and you know if it's too scary +if this kind of stuff is too scary you + + align:start position:0% +if this kind of stuff is too scary you + + + align:start position:0% +if this kind of stuff is too scary you +don't have to look inside of it so that + + align:start position:0% +don't have to look inside of it so that + + + align:start position:0% +don't have to look inside of it so that +might make you feel better but the point + + align:start position:0% +might make you feel better but the point + + + align:start position:0% +might make you feel better but the point +is it it really could work this way and + + align:start position:0% +is it it really could work this way and + + + align:start position:0% +is it it really could work this way and +it wouldn't make any difference to the + + align:start position:0% +it wouldn't make any difference to the + + + align:start position:0% +it wouldn't make any difference to the +system at all + + align:start position:0% +system at all + + + align:start position:0% +system at all +so in some sense we don't need data at + + align:start position:0% +so in some sense we don't need data at + + + align:start position:0% +so in some sense we don't need data at +all to build these data abstractions + + align:start position:0% +all to build these data abstractions + + + align:start position:0% +all to build these data abstractions +because we can do everything in terms of + + align:start position:0% +because we can do everything in terms of + + + align:start position:0% +because we can do everything in terms of +procedures + + align:start position:0% +procedures + + + align:start position:0% +procedures +Okay. Well, why did I terrify you in + + align:start position:0% +Okay. Well, why did I terrify you in + + + align:start position:0% +Okay. Well, why did I terrify you in +this way? First, I really want to + + align:start position:0% +this way? First, I really want to + + + align:start position:0% +this way? First, I really want to +reinforce this idea of abstraction + + align:start position:0% +reinforce this idea of abstraction + + + align:start position:0% +reinforce this idea of abstraction +that you really can do these things + + align:start position:0% +that you really can do these things + + + align:start position:0% +that you really can do these things +abstractly. + + align:start position:0% +abstractly. + + + align:start position:0% +abstractly. +Secondly, I want to introduce + + align:start position:0% +Secondly, I want to introduce + + + align:start position:0% +Secondly, I want to introduce +an idea we're going to see more and more + + align:start position:0% +an idea we're going to see more and more + + + align:start position:0% +an idea we're going to see more and more +of in this course, + + align:start position:0% +of in this course, + + + align:start position:0% +of in this course, +which is we're going to blur the line + + align:start position:0% +which is we're going to blur the line + + + align:start position:0% +which is we're going to blur the line +between what's data and what's a + + align:start position:0% +between what's data and what's a + + + align:start position:0% +between what's data and what's a +procedure. + + align:start position:0% +procedure. + + + align:start position:0% +procedure. +See in this funny implementation it + + align:start position:0% +See in this funny implementation it + + + align:start position:0% +See in this funny implementation it +turned out that that con of something + + align:start position:0% +turned out that that con of something + + + align:start position:0% +turned out that that con of something +happened to be represented in terms of a + + align:start position:0% +happened to be represented in terms of a + + + align:start position:0% +happened to be represented in terms of a +procedure even though we think of it as + + align:start position:0% +procedure even though we think of it as + + + align:start position:0% +procedure even though we think of it as +data. + + align:start position:0% + + + + align:start position:0% + +Well here that's sort of a mathematical + + align:start position:0% +Well here that's sort of a mathematical + + + align:start position:0% +Well here that's sort of a mathematical +trick. But one of the things we'll see + + align:start position:0% +trick. But one of the things we'll see + + + align:start position:0% +trick. But one of the things we'll see +is that a lot of the very important + + align:start position:0% +is that a lot of the very important + + + align:start position:0% +is that a lot of the very important +programming techniques that we're going + + align:start position:0% +programming techniques that we're going + + + align:start position:0% +programming techniques that we're going +to get to refer sort of depend very + + align:start position:0% +to get to refer sort of depend very + + + align:start position:0% +to get to refer sort of depend very +crucially on blurring this this + + align:start position:0% +crucially on blurring this this + + + align:start position:0% +crucially on blurring this this +traditional line between what you + + align:start position:0% +traditional line between what you + + + align:start position:0% +traditional line between what you +consider a procedure and what you + + align:start position:0% +consider a procedure and what you + + + align:start position:0% +consider a procedure and what you +consider data. We're going to see more + + align:start position:0% +consider data. We're going to see more + + + align:start position:0% +consider data. We're going to see more +and more of that especially next time. + + align:start position:0% +and more of that especially next time. + + + align:start position:0% +and more of that especially next time. +Okay, questions. + + align:start position:0% +Okay, questions. + + + align:start position:0% +Okay, questions. +If + + align:start position:0% +If + + + align:start position:0% +If +you asked uh the system to print a what + + align:start position:0% +you asked uh the system to print a what + + + align:start position:0% +you asked uh the system to print a what +would be the result? Uh the question is + + align:start position:0% +would be the result? Uh the question is + + + align:start position:0% +would be the result? Uh the question is +what? + + align:start position:0% +what? + + + align:start position:0% +what? +The question is what would happen if I + + align:start position:0% +The question is what would happen if I + + + align:start position:0% +The question is what would happen if I +asked the system to print a given this + + align:start position:0% +asked the system to print a given this + + + align:start position:0% +asked the system to print a given this +representation? You already know the + + align:start position:0% +representation? You already know the + + + align:start position:0% +representation? You already know the +answer. + + align:start position:0% +answer. + + + align:start position:0% +answer. +Right? The answer is + + align:start position:0% + + + + align:start position:0% + +compound procedure A. Just like last + + align:start position:0% +compound procedure A. Just like last + + + align:start position:0% +compound procedure A. Just like last +time + + align:start position:0% + + + + align:start position:0% + +we say compound procedure + + align:start position:0% + + + + align:start position:0% + +might say a little bit more. I might say + + align:start position:0% +might say a little bit more. I might say + + + align:start position:0% +might say a little bit more. I might say +compound procedure lambda something or + + align:start position:0% +compound procedure lambda something or + + + align:start position:0% +compound procedure lambda something or +other depending on details of how I + + align:start position:0% +other depending on details of how I + + + align:start position:0% +other depending on details of how I +named it but it's a procedure and the + + align:start position:0% +named it but it's a procedure and the + + + align:start position:0% +named it but it's a procedure and the +only reason for that is I haven't told + + align:start position:0% +only reason for that is I haven't told + + + align:start position:0% +only reason for that is I haven't told +the system anything special about how to + + align:start position:0% +the system anything special about how to + + + align:start position:0% +the system anything special about how to +print such things now it's in fact true + + align:start position:0% +print such things now it's in fact true + + + align:start position:0% +print such things now it's in fact true +that with the actual implementation of + + align:start position:0% +that with the actual implementation of + + + align:start position:0% +that with the actual implementation of +con that happens to be built in the + + align:start position:0% +con that happens to be built in the + + + align:start position:0% +con that happens to be built in the +system it would print something else it + + align:start position:0% +system it would print something else it + + + align:start position:0% +system it would print something else it +would print say this is a pair + + align:start position:0% + + + + align:start position:0% + +um when you define cons + + align:start position:0% + + + + align:start position:0% + +And then you pass it in two values. + + align:start position:0% +And then you pass it in two values. + + + align:start position:0% +And then you pass it in two values. +How does it know where to look for the + + align:start position:0% +How does it know where to look for the + + + align:start position:0% +How does it know where to look for the +cons? Because you can use cons over and + + align:start position:0% +cons? Because you can use cons over and + + + align:start position:0% +cons? Because you can use cons over and +over again. So how does it know where to + + align:start position:0% +over again. So how does it know where to + + + align:start position:0% +over again. So how does it know where to +look to know which A and B it's supposed + + align:start position:0% +look to know which A and B it's supposed + + + align:start position:0% +look to know which A and B it's supposed +to pull back out. I don't know if that + + align:start position:0% +to pull back out. I don't know if that + + + align:start position:0% +to pull back out. I don't know if that +expressing that quite right. + + align:start position:0% +expressing that quite right. + + + align:start position:0% +expressing that quite right. +Okay. The question is + + align:start position:0% +Okay. The question is + + + align:start position:0% +Okay. The question is +where is it stored? + + align:start position:0% +where is it stored? + + + align:start position:0% +where is it stored? +Okay. The question is + + align:start position:0% +Okay. The question is + + + align:start position:0% +Okay. The question is +I sort of have a conce with a with a 37 + + align:start position:0% +I sort of have a conce with a with a 37 + + + align:start position:0% +I sort of have a conce with a with a 37 +and a 49 and I might make another con + + align:start position:0% +and a 49 and I might make another con + + + align:start position:0% +and a 49 and I might make another con +with a one and a two and I might have + + align:start position:0% +with a one and a two and I might have + + + align:start position:0% +with a one and a two and I might have +one called A and might have one called B + + align:start position:0% +one called A and might have one called B + + + align:start position:0% +one called A and might have one called B +and the question is how does it know and + + align:start position:0% +and the question is how does it know and + + + align:start position:0% +and the question is how does it know and +why don't they get confused and that's a + + align:start position:0% +why don't they get confused and that's a + + + align:start position:0% +why don't they get confused and that's a +very that's a very good question. + + align:start position:0% +very that's a very good question. + + + align:start position:0% +very that's a very good question. +What it see you have to really believe + + align:start position:0% +What it see you have to really believe + + + align:start position:0% +What it see you have to really believe +that the procedures are objects. + + align:start position:0% +that the procedures are objects. + + + align:start position:0% +that the procedures are objects. +See it's sort of it's sort of like + + align:start position:0% +See it's sort of it's sort of like + + + align:start position:0% +See it's sort of it's sort of like +saying let's try another simpler + + align:start position:0% +saying let's try another simpler + + + align:start position:0% +saying let's try another simpler +example. + + align:start position:0% +example. + + + align:start position:0% +example. +Suppose I ask for the square root of + + align:start position:0% +Suppose I ask for the square root of + + + align:start position:0% +Suppose I ask for the square root of +three. + + align:start position:0% + + + + align:start position:0% + +So I ask for the square root of five and + + align:start position:0% +So I ask for the square root of five and + + + align:start position:0% +So I ask for the square root of five and +then I ask for the square root + + align:start position:0% +then I ask for the square root + + + align:start position:0% +then I ask for the square root +of 20. + + align:start position:0% + + + + align:start position:0% + +You're probably not the least bit + + align:start position:0% +You're probably not the least bit + + + align:start position:0% +You're probably not the least bit +bothered like I that I can take square + + align:start position:0% +bothered like I that I can take square + + + align:start position:0% +bothered like I that I can take square +root and apply it to five and then I can + + align:start position:0% +root and apply it to five and then I can + + + align:start position:0% +root and apply it to five and then I can +take square root and apply it to 20 + + align:start position:0% +take square root and apply it to 20 + + + align:start position:0% +take square root and apply it to 20 +and there's sort of no issue. Doesn't it + + align:start position:0% +and there's sort of no issue. Doesn't it + + + align:start position:0% +and there's sort of no issue. Doesn't it +get confused about whether it's working + + align:start position:0% +get confused about whether it's working + + + align:start position:0% +get confused about whether it's working +on five or 20? There's no issue about + + align:start position:0% +on five or 20? There's no issue about + + + align:start position:0% +on five or 20? There's no issue about +that because you're thinking of a + + align:start position:0% +that because you're thinking of a + + + align:start position:0% +that because you're thinking of a +procedure which goes off and and does + + align:start position:0% +procedure which goes off and and does + + + align:start position:0% +procedure which goes off and and does +something. + + align:start position:0% +something. + + + align:start position:0% +something. +Now, in some sense, you're asking me the + + align:start position:0% +Now, in some sense, you're asking me the + + + align:start position:0% +Now, in some sense, you're asking me the +same question, + + align:start position:0% +same question, + + + align:start position:0% +same question, +but it's really bothering you and it's + + align:start position:0% +but it's really bothering you and it's + + + align:start position:0% +but it's really bothering you and it's +bothering you for a really good reason + + align:start position:0% +bothering you for a really good reason + + + align:start position:0% +bothering you for a really good reason +because when I write that you're saying, + + align:start position:0% +because when I write that you're saying, + + + align:start position:0% +because when I write that you're saying, +gee, this is I know sort of a procedure, + + align:start position:0% +gee, this is I know sort of a procedure, + + + align:start position:0% +gee, this is I know sort of a procedure, +but it's not a procedure that's just + + align:start position:0% +but it's not a procedure that's just + + + align:start position:0% +but it's not a procedure that's just +running. It's just sort of a procedure + + align:start position:0% +running. It's just sort of a procedure + + + align:start position:0% +running. It's just sort of a procedure +sitting there. And how can it be that + + align:start position:0% +sitting there. And how can it be that + + + align:start position:0% +sitting there. And how can it be that +sometimes this procedure has 37 and 49 + + align:start position:0% +sometimes this procedure has 37 and 49 + + + align:start position:0% +sometimes this procedure has 37 and 49 +and there might be another one which has + + align:start position:0% +and there might be another one which has + + + align:start position:0% +and there might be another one which has +uh five and six in there and why don't + + align:start position:0% +uh five and six in there and why don't + + + align:start position:0% +uh five and six in there and why don't +they get confused? + + align:start position:0% +they get confused? + + + align:start position:0% +they get confused? +See, so you're really there's something + + align:start position:0% +See, so you're really there's something + + + align:start position:0% +See, so you're really there's something +very very important that's bothering you + + align:start position:0% +very very important that's bothering you + + + align:start position:0% +very very important that's bothering you +and it's really crucial to what's going + + align:start position:0% +and it's really crucial to what's going + + + align:start position:0% +and it's really crucial to what's going +on. It's we're suddenly saying that + + align:start position:0% +on. It's we're suddenly saying that + + + align:start position:0% +on. It's we're suddenly saying that +procedures are not just + + align:start position:0% +procedures are not just + + + align:start position:0% +procedures are not just +the act of doing something. + + align:start position:0% +the act of doing something. + + + align:start position:0% +the act of doing something. +Procedures are conceptual entities, + + align:start position:0% +Procedures are conceptual entities, + + + align:start position:0% +Procedures are conceptual entities, +objects. And if I build and if I build + + align:start position:0% +objects. And if I build and if I build + + + align:start position:0% +objects. And if I build and if I build +cons of 37 and 49 that's a particular + + align:start position:0% +cons of 37 and 49 that's a particular + + + align:start position:0% +cons of 37 and 49 that's a particular +procedure that sits there + + align:start position:0% +procedure that sits there + + + align:start position:0% +procedure that sits there +and it's different from car + + align:start position:0% +and it's different from car + + + align:start position:0% +and it's different from car +and it's different from cons of three + + align:start position:0% +and it's different from cons of three + + + align:start position:0% +and it's different from cons of three +and four that's another procedure that + + align:start position:0% +and four that's another procedure that + + + align:start position:0% +and four that's another procedure that +sits there + + align:start position:0% +sits there + + + align:start position:0% +sits there +exists independently + + align:start position:0% +exists independently + + + align:start position:0% +exists independently +and exists independently + + align:start position:0% +and exists independently + + + align:start position:0% +and exists independently +and they both can be referenced by car + + align:start position:0% +and they both can be referenced by car + + + align:start position:0% +and they both can be referenced by car +and cter + + align:start position:0% +and cter + + + align:start position:0% +and cter +and they both would be referenced by car + + align:start position:0% +and they both would be referenced by car + + + align:start position:0% +and they both would be referenced by car +and cuddter just like I could you know + + align:start position:0% +and cuddter just like I could you know + + + align:start position:0% +and cuddter just like I could you know +just like I could increment this and I + + align:start position:0% +just like I could increment this and I + + + align:start position:0% +just like I could increment this and I +could increment increment that they're + + align:start position:0% +could increment increment that they're + + + align:start position:0% +could increment increment that they're +objects and that's that's sort of where + + align:start position:0% +objects and that's that's sort of where + + + align:start position:0% +objects and that's that's sort of where +we're going. See, the fact that you're + + align:start position:0% +we're going. See, the fact that you're + + + align:start position:0% +we're going. See, the fact that you're +asking the question shows that you're + + align:start position:0% +asking the question shows that you're + + + align:start position:0% +asking the question shows that you're +really starting to think about the + + align:start position:0% +really starting to think about the + + + align:start position:0% +really starting to think about the +implications of of what's going on. It's + + align:start position:0% +implications of of what's going on. It's + + + align:start position:0% +implications of of what's going on. It's +the difference between saying a + + align:start position:0% +the difference between saying a + + + align:start position:0% +the difference between saying a +procedure is just the act of doing + + align:start position:0% +procedure is just the act of doing + + + align:start position:0% +procedure is just the act of doing +something and a procedure is a real + + align:start position:0% +something and a procedure is a real + + + align:start position:0% +something and a procedure is a real +object that has existence. + + align:start position:0% +object that has existence. + + + align:start position:0% +object that has existence. +So when the procedure gets built, the + + align:start position:0% +So when the procedure gets built, the + + + align:start position:0% +So when the procedure gets built, the +actual values are now substituted for A + + align:start position:0% +actual values are now substituted for A + + + align:start position:0% +actual values are now substituted for A +and B and that procedure exists as a + + align:start position:0% +and B and that procedure exists as a + + + align:start position:0% +and B and that procedure exists as a +lambda and is what's actually passed in. + + align:start position:0% +lambda and is what's actually passed in. + + + align:start position:0% +lambda and is what's actually passed in. +Yes. when when cons gets called and the + + align:start position:0% +Yes. when when cons gets called and the + + + align:start position:0% +Yes. when when cons gets called and the +result of cons is a new procedure that's + + align:start position:0% +result of cons is a new procedure that's + + + align:start position:0% +result of cons is a new procedure that's +constructed that new procedure has an + + align:start position:0% +constructed that new procedure has an + + + align:start position:0% +constructed that new procedure has an +argument that's called pick + + align:start position:0% +argument that's called pick + + + align:start position:0% +argument that's called pick +but it no longer has an A and B the A + + align:start position:0% +but it no longer has an A and B the A + + + align:start position:0% +but it no longer has an A and B the A +and B are the actual values that were + + align:start position:0% +and B are the actual values that were + + + align:start position:0% +and B are the actual values that were +passed + + align:start position:0% +passed + + + align:start position:0% +passed +and it has right according to the + + align:start position:0% +and it has right according to the + + + align:start position:0% +and it has right according to the +substitution model what it now has is + + align:start position:0% +substitution model what it now has is + + + align:start position:0% +substitution model what it now has is +not those arbitrary names A and B it + + align:start position:0% +not those arbitrary names A and B it + + + align:start position:0% +not those arbitrary names A and B it +somehow has that 37 and 49 in there + + align:start position:0% +somehow has that 37 and 49 in there + + + align:start position:0% +somehow has that 37 and 49 in there +but you're right that's a hard thing to + + align:start position:0% +but you're right that's a hard thing to + + + align:start position:0% +but you're right that's a hard thing to +think about and it's different from the + + align:start position:0% +think about and it's different from the + + + align:start position:0% +think about and it's different from the +way you've been thinking about + + align:start position:0% +way you've been thinking about + + + align:start position:0% +way you've been thinking about +procedures + + align:start position:0% +procedures + + + align:start position:0% +procedures +and if I have again con of 37 and 49 + + align:start position:0% +and if I have again con of 37 and 49 + + + align:start position:0% +and if I have again con of 37 and 49 +it's a different option + + align:start position:0% +it's a different option + + + align:start position:0% +it's a different option +and if you make + + align:start position:0% +and if you make + + + align:start position:0% +and if you make +and if you + + align:start position:0% +and if you + + + align:start position:0% +and if you +make another con of 37 and 49 + + align:start position:0% + + + + align:start position:0% + +you're into a wonderful philosophical + + align:start position:0% +you're into a wonderful philosophical + + + align:start position:0% +you're into a wonderful philosophical +problem which is going to be what the + + align:start position:0% +problem which is going to be what the + + + align:start position:0% +problem which is going to be what the +lecture about halfway through this + + align:start position:0% +lecture about halfway through this + + + align:start position:0% +lecture about halfway through this +course is about + + align:start position:0% +course is about + + + align:start position:0% +course is about +which is if I con 37 and 49 and I do it + + align:start position:0% +which is if I con 37 and 49 and I do it + + + align:start position:0% +which is if I con 37 and 49 and I do it +again is that the same thing or is it a + + align:start position:0% +again is that the same thing or is it a + + + align:start position:0% +again is that the same thing or is it a +different thing and how could you tell + + align:start position:0% +different thing and how could you tell + + + align:start position:0% +different thing and how could you tell +and when could it possibly matter? And + + align:start position:0% +and when could it possibly matter? And + + + align:start position:0% +and when could it possibly matter? And +that's like saying is + + align:start position:0% + + + + align:start position:0% + +that's sort of like saying is + + align:start position:0% +that's sort of like saying is + + + align:start position:0% +that's sort of like saying is +is that the same thing as as this + + align:start position:0% +is that the same thing as as this + + + align:start position:0% +is that the same thing as as this +or is this the same thing as that? It's + + align:start position:0% +or is this the same thing as that? It's + + + align:start position:0% +or is this the same thing as that? It's +the same kind of question and that's a + + align:start position:0% +the same kind of question and that's a + + + align:start position:0% +the same kind of question and that's a +very that's a very very deep question + + align:start position:0% +very that's a very very deep question + + + align:start position:0% +very that's a very very deep question +and I can't answer it in less than an + + align:start position:0% +and I can't answer it in less than an + + + align:start position:0% +and I can't answer it in less than an +hour but we will + + align:start position:0% +hour but we will + + + align:start position:0% +hour but we will +[Music] \ No newline at end of file diff --git a/zI9cSV3QKz0.txt b/zI9cSV3QKz0.txt new file mode 100644 index 0000000000000000000000000000000000000000..a7ea783ffdeb2e4fcb3384cdd08d78ff4c68372d --- /dev/null +++ b/zI9cSV3QKz0.txt @@ -0,0 +1,7851 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +to view additional materials from + + align:start position:0% +to view additional materials from + + + align:start position:0% +to view additional materials from +hundreds of MIT courses visit MIT open + + align:start position:0% +hundreds of MIT courses visit MIT open + + + align:start position:0% +hundreds of MIT courses visit MIT open +courseware at ocw.mit.edu + + align:start position:0% + + + + align:start position:0% + +so I'm ready for anything as as or hope + + align:start position:0% +so I'm ready for anything as as or hope + + + align:start position:0% +so I'm ready for anything as as or hope +I am uh questions about any topics yes + + align:start position:0% +I am uh questions about any topics yes + + + align:start position:0% +I am uh questions about any topics yes +okay so I feel there's is like a White + + align:start position:0% +okay so I feel there's is like a White + + + align:start position:0% +okay so I feel there's is like a White +House Press Conference I think there's + + align:start position:0% +House Press Conference I think there's + + + align:start position:0% +House Press Conference I think there's +always somebody in the front row who who + + align:start position:0% +always somebody in the front row who who + + + align:start position:0% +always somebody in the front row who who +who who gets to ask the first question + + align:start position:0% +who who gets to ask the first question + + + align:start position:0% +who who gets to ask the first question +and then gets to say Thank you Mr + + align:start position:0% +and then gets to say Thank you Mr + + + align:start position:0% +and then gets to say Thank you Mr +President at the end and then I'm off uh + + align:start position:0% +President at the end and then I'm off uh + + + align:start position:0% +President at the end and then I'm off uh +but I don't + + align:start position:0% +but I don't + + + align:start position:0% +but I don't +yes + + align:start position:0% +yes + + + align:start position:0% +yes +yeah this has I'm tempted by the way to + + align:start position:0% +yeah this has I'm tempted by the way to + + + align:start position:0% +yeah this has I'm tempted by the way to +ask you all are you going to vote next + + align:start position:0% +ask you all are you going to vote next + + + align:start position:0% +ask you all are you going to vote next +Tuesday and of course I'd like to know + + align:start position:0% +Tuesday and of course I'd like to know + + + align:start position:0% +Tuesday and of course I'd like to know +who you vote for and I'd like to give + + align:start position:0% +who you vote for and I'd like to give + + + align:start position:0% +who you vote for and I'd like to give +you my advice but uh I don't know that + + align:start position:0% +you my advice but uh I don't know that + + + align:start position:0% +you my advice but uh I don't know that +that's proper if anybody wants advice + + align:start position:0% +that's proper if anybody wants advice + + + align:start position:0% +that's proper if anybody wants advice +they can email but but please vote + + align:start position:0% +they can email but but please vote + + + align:start position:0% +they can email but but please vote +please vote yeah yeah all right question + + align:start position:0% +please vote yeah yeah all right question + + + align:start position:0% +please vote yeah yeah all right question +here and then we'll have + + align:start position:0% +here and then we'll have + + + align:start position:0% +here and then we'll have +yeah um so I looked online and I started + + align:start position:0% +yeah um so I looked online and I started + + + align:start position:0% +yeah um so I looked online and I started +with + + align:start position:0% +with + + + align:start position:0% +with +number two oh okay so those were just + + align:start position:0% +number two oh okay so those were just + + + align:start position:0% +number two oh okay so those were just +posted like yeah I see okay 3.3 number + + align:start position:0% +posted like yeah I see okay 3.3 number + + + align:start position:0% +posted like yeah I see okay 3.3 number +two it seems like it should be a very + + align:start position:0% +two it seems like it should be a very + + + align:start position:0% +two it seems like it should be a very +straight question not finding aall + + align:start position:0% +straight question not finding aall + + + align:start position:0% +straight question not finding aall +to W I'm finding okay so that this was a + + align:start position:0% +to W I'm finding okay so that this was a + + + align:start position:0% +to W I'm finding okay so that this was a +a case yeah right uh oh okay it could be + + align:start position:0% +a case yeah right uh oh okay it could be + + + align:start position:0% +a case yeah right uh oh okay it could be +wrong so let's just so that's a a so so + + align:start position:0% +wrong so let's just so that's a a so so + + + align:start position:0% +wrong so let's just so that's a a so so +this is 3.3 number two asks you about + + align:start position:0% +this is 3.3 number two asks you about + + + align:start position:0% +this is 3.3 number two asks you about +the uh flow field + + align:start position:0% +the uh flow field + + + align:start position:0% +the uh flow field +uh which is has no flow in the X + + align:start position:0% +uh which is has no flow in the X + + + align:start position:0% +uh which is has no flow in the X +Direction + + align:start position:0% +Direction + + + align:start position:0% +Direction +the Velocity in the X direction is zero + + align:start position:0% +the Velocity in the X direction is zero + + + align:start position:0% +the Velocity in the X direction is zero +the Velocity in the y direction is X + + align:start position:0% +the Velocity in the y direction is X + + + align:start position:0% +the Velocity in the y direction is X +okay so suppose we just take that as a a + + align:start position:0% +okay so suppose we just take that as a a + + + align:start position:0% +okay so suppose we just take that as a a +flow field and try to understand is it a + + align:start position:0% +flow field and try to understand is it a + + + align:start position:0% +flow field and try to understand is it a +gradient I mean so what are the + + align:start position:0% +gradient I mean so what are the + + + align:start position:0% +gradient I mean so what are the +questions I would ask is it a gradient + + align:start position:0% +questions I would ask is it a gradient + + + align:start position:0% +questions I would ask is it a gradient +of anything because as we're we're now + + align:start position:0% +of anything because as we're we're now + + + align:start position:0% +of anything because as we're we're now +thinking V and W are pretty much the + + align:start position:0% +thinking V and W are pretty much the + + + align:start position:0% +thinking V and W are pretty much the +same guy so is it a gradient yes or no + + align:start position:0% +same guy so is it a gradient yes or no + + + align:start position:0% +same guy so is it a gradient yes or no +if so what's the potential is it does is + + align:start position:0% +if so what's the potential is it does is + + + align:start position:0% +if so what's the potential is it does is +it diver free yes or no if it is what's + + align:start position:0% +it diver free yes or no if it is what's + + + align:start position:0% +it diver free yes or no if it is what's +the stream function and of course if it + + align:start position:0% +the stream function and of course if it + + + align:start position:0% +the stream function and of course if it +if the answer to both tests was yes then + + align:start position:0% +if the answer to both tests was yes then + + + align:start position:0% +if the answer to both tests was yes then +we would be talking about lass's + + align:start position:0% +we would be talking about lass's + + + align:start position:0% +we would be talking about lass's +equation I suspect for this example the + + align:start position:0% +equation I suspect for this example the + + + align:start position:0% +equation I suspect for this example the +answers to answer at least to one of the + + align:start position:0% +answers to answer at least to one of the + + + align:start position:0% +answers to answer at least to one of the +two questions will be no so we're not + + align:start position:0% +two questions will be no so we're not + + + align:start position:0% +two questions will be no so we're not +we're not we won't have the two pieces + + align:start position:0% +we're not we won't have the two pieces + + + align:start position:0% +we're not we won't have the two pieces +coming together into La PL okay so first + + align:start position:0% +coming together into La PL okay so first + + + align:start position:0% +coming together into La PL okay so first +of all is it a gradient what's the test + + align:start position:0% +of all is it a gradient what's the test + + + align:start position:0% +of all is it a gradient what's the test +for is this the gradient so is this so + + align:start position:0% +for is this the gradient so is this so + + + align:start position:0% +for is this the gradient so is this so +the my two questions are uh is V the + + align:start position:0% +the my two questions are uh is V the + + + align:start position:0% +the my two questions are uh is V the +gradient of some U + + align:start position:0% +gradient of some U + + + align:start position:0% +gradient of some U +and what's the test for that + + align:start position:0% +and what's the test for that + + + align:start position:0% +and what's the test for that +uh you remember if it is the gradient + + align:start position:0% +uh you remember if it is the gradient + + + align:start position:0% +uh you remember if it is the gradient +see I could remember myself if it is a + + align:start position:0% +see I could remember myself if it is a + + + align:start position:0% +see I could remember myself if it is a +gradient then this is dudx and this is + + align:start position:0% +gradient then this is dudx and this is + + + align:start position:0% +gradient then this is dudx and this is +dudy + + align:start position:0% +dudy + + + align:start position:0% +dudy +and the condition that V1 and V2 would + + align:start position:0% +and the condition that V1 and V2 would + + + align:start position:0% +and the condition that V1 and V2 would +have to satisfy is that the Y derivative + + align:start position:0% +have to satisfy is that the Y derivative + + + align:start position:0% +have to satisfy is that the Y derivative +of that would have to equal the X + + align:start position:0% +of that would have to equal the X + + + align:start position:0% +of that would have to equal the X +derivative of that because on the right + + align:start position:0% +derivative of that because on the right + + + align:start position:0% +derivative of that because on the right +hand side they are the same uxy is the + + align:start position:0% +hand side they are the same uxy is the + + + align:start position:0% +hand side they are the same uxy is the +same as uyx so I would look at at at uh + + align:start position:0% +same as uyx so I would look at at at uh + + + align:start position:0% +same as uyx so I would look at at at uh +so I need so let me write that again I + + align:start position:0% +so I need so let me write that again I + + + align:start position:0% +so I need so let me write that again I +need + + align:start position:0% +need + + + align:start position:0% +need +dv1 + + align:start position:0% +dv1 + + + align:start position:0% +dv1 +Dy + + align:start position:0% +Dy + + + align:start position:0% +Dy +to equal dv2 DX and is that true in this + + align:start position:0% +to equal dv2 DX and is that true in this + + + align:start position:0% +to equal dv2 DX and is that true in this +in this example + + align:start position:0% +in this example + + + align:start position:0% +in this example +what's what's dv1 Dy + + align:start position:0% +what's what's dv1 Dy + + + align:start position:0% +what's what's dv1 Dy +zero what's dv2 DX + + align:start position:0% +zero what's dv2 DX + + + align:start position:0% +zero what's dv2 DX +one so the answer is no okay so test + + align:start position:0% +one so the answer is no okay so test + + + align:start position:0% +one so the answer is no okay so test +failed + + align:start position:0% +failed + + + align:start position:0% +failed +all right the second question is + + align:start position:0% +all right the second question is + + + align:start position:0% +all right the second question is +is it does it possibly play sit over in + + align:start position:0% +is it does it possibly play sit over in + + + align:start position:0% +is it does it possibly play sit over in +the Divergence free world is the + + align:start position:0% +the Divergence free world is the + + + align:start position:0% +the Divergence free world is the +Divergence of and now I'll call it w + + align:start position:0% +Divergence of and now I'll call it w + + + align:start position:0% +Divergence of and now I'll call it w +equals z so I take the so the answer was + + align:start position:0% +equals z so I take the so the answer was + + + align:start position:0% +equals z so I take the so the answer was +no to that question but now I think the + + align:start position:0% +no to that question but now I think the + + + align:start position:0% +no to that question but now I think the +answer to this question will be yes + + align:start position:0% +answer to this question will be yes + + + align:start position:0% +answer to this question will be yes +because the what's the Divergence of + + align:start position:0% +because the what's the Divergence of + + + align:start position:0% +because the what's the Divergence of +this thing the it's the X derivative of + + align:start position:0% +this thing the it's the X derivative of + + + align:start position:0% +this thing the it's the X derivative of +that which is certainly zero plus the Y + + align:start position:0% +that which is certainly zero plus the Y + + + align:start position:0% +that which is certainly zero plus the Y +derivative of that which is certainly + + align:start position:0% +derivative of that which is certainly + + + align:start position:0% +derivative of that which is certainly +zero so the answer is yes so it is so so + + align:start position:0% +zero so the answer is yes so it is so so + + + align:start position:0% +zero so the answer is yes so it is so so +there's no potential but there is a + + align:start position:0% +there's no potential but there is a + + + align:start position:0% +there's no potential but there is a +stream function right because the stream + + align:start position:0% +stream function right because the stream + + + align:start position:0% +stream function right because the stream +function comes in with this test so + + align:start position:0% +function comes in with this test so + + + align:start position:0% +function comes in with this test so +let's remember what just just from + + align:start position:0% +let's remember what just just from + + + align:start position:0% +let's remember what just just from +today's lecture what was the stream + + align:start position:0% +today's lecture what was the stream + + + align:start position:0% +today's lecture what was the stream +function when when the D from dw1 DX + + align:start position:0% +function when when the D from dw1 DX + + + align:start position:0% +function when when the D from dw1 DX +plus dw2 Dy equals z that will be + + align:start position:0% +plus dw2 Dy equals z that will be + + + align:start position:0% +plus dw2 Dy equals z that will be +satisfied if W1 is the Y derivative of + + align:start position:0% +satisfied if W1 is the Y derivative of + + + align:start position:0% +satisfied if W1 is the Y derivative of +the stream function and W2 is minus the + + align:start position:0% +the stream function and W2 is minus the + + + align:start position:0% +the stream function and W2 is minus the +X derivative + + align:start position:0% +X derivative + + + align:start position:0% +X derivative +because if I if then the this matches + + align:start position:0% +because if I if then the this matches + + + align:start position:0% +because if I if then the this matches +the X derivative of this plus the Y + + align:start position:0% +the X derivative of this plus the Y + + + align:start position:0% +the X derivative of this plus the Y +derivative of this which is the + + align:start position:0% +derivative of this which is the + + + align:start position:0% +derivative of this which is the +Divergence on the right hand side I + + align:start position:0% +Divergence on the right hand side I + + + align:start position:0% +Divergence on the right hand side I +would get zero so there's got to be an S + + align:start position:0% +would get zero so there's got to be an S + + + align:start position:0% +would get zero so there's got to be an S +and what is it probably not hard to find + + align:start position:0% +and what is it probably not hard to find + + + align:start position:0% +and what is it probably not hard to find +let's see + + align:start position:0% +let's see + + + align:start position:0% +let's see +here W1 is zero so that tells me S + + align:start position:0% +here W1 is zero so that tells me S + + + align:start position:0% +here W1 is zero so that tells me S +doesn't depend on Y at all + + align:start position:0% +doesn't depend on Y at all + + + align:start position:0% +doesn't depend on Y at all +W2 is X so X is supposed to be minus the + + align:start position:0% +W2 is X so X is supposed to be minus the + + + align:start position:0% +W2 is X so X is supposed to be minus the +X derivative of the stream function so + + align:start position:0% +X derivative of the stream function so + + + align:start position:0% +X derivative of the stream function so +what's what is the stream function then + + align:start position:0% +what's what is the stream function then + + + align:start position:0% +what's what is the stream function then +have I got room to put it here + + align:start position:0% +have I got room to put it here + + + align:start position:0% +have I got room to put it here +just about what will work + + align:start position:0% + + + + align:start position:0% + +it's so again here's W1 the Y derivative + + align:start position:0% +it's so again here's W1 the Y derivative + + + align:start position:0% +it's so again here's W1 the Y derivative +of s is zero W2 tells me that the X + + align:start position:0% +of s is zero W2 tells me that the X + + + align:start position:0% +of s is zero W2 tells me that the X +derivative of s is minus X so all I'm + + align:start position:0% +derivative of s is minus X so all I'm + + + align:start position:0% +derivative of s is minus X so all I'm +looking for is a function that only + + align:start position:0% +looking for is a function that only + + + align:start position:0% +looking for is a function that only +depends on X has no dependence on Y and + + align:start position:0% +depends on X has no dependence on Y and + + + align:start position:0% +depends on X has no dependence on Y and +its derivative should be minus X so + + align:start position:0% +its derivative should be minus X so + + + align:start position:0% +its derivative should be minus X so +what's the function + + align:start position:0% +what's the function + + + align:start position:0% +what's the function +minus + + align:start position:0% +minus + + + align:start position:0% +minus +minus a half of x s yeah let me let me + + align:start position:0% +minus a half of x s yeah let me let me + + + align:start position:0% +minus a half of x s yeah let me let me +so so so this gives me S = minus a half + + align:start position:0% +so so so this gives me S = minus a half + + + align:start position:0% +so so so this gives me S = minus a half +of x^2 + + align:start position:0% +of x^2 + + + align:start position:0% +of x^2 +okay all right so you're saying that + + align:start position:0% +okay all right so you're saying that + + + align:start position:0% +okay all right so you're saying that +yeah so uh so there is a string function + + align:start position:0% +yeah so uh so there is a string function + + + align:start position:0% +yeah so uh so there is a string function +right and what does that travel along + + align:start position:0% +right and what does that travel along + + + align:start position:0% +right and what does that travel along +that travels along stream that means + + align:start position:0% +that travels along stream that means + + + align:start position:0% +that travels along stream that means +that the flow buzzes along stream lines + + align:start position:0% +that the flow buzzes along stream lines + + + align:start position:0% +that the flow buzzes along stream lines +and what are the stream lines they're + + align:start position:0% +and what are the stream lines they're + + + align:start position:0% +and what are the stream lines they're +the lines where s is constant + + align:start position:0% +the lines where s is constant + + + align:start position:0% +the lines where s is constant +equip potentials were the lines where U + + align:start position:0% +equip potentials were the lines where U + + + align:start position:0% +equip potentials were the lines where U +was constant but here we don't have a u + + align:start position:0% +was constant but here we don't have a u + + + align:start position:0% +was constant but here we don't have a u +in this problem stream lines are lines + + align:start position:0% +in this problem stream lines are lines + + + align:start position:0% +in this problem stream lines are lines +where the S is constant so - half x^2 is + + align:start position:0% +where the S is constant so - half x^2 is + + + align:start position:0% +where the S is constant so - half x^2 is +constant what what's the picture look + + align:start position:0% +constant what what's the picture look + + + align:start position:0% +constant what what's the picture look +like + + align:start position:0% + + + + align:start position:0% + +the picture then for that + + align:start position:0% +the picture then for that + + + align:start position:0% +the picture then for that +well and you you know where where what + + align:start position:0% +well and you you know where where what + + + align:start position:0% +well and you you know where where what +the flow is doing at a typical Point + + align:start position:0% +the flow is doing at a typical Point + + + align:start position:0% +the flow is doing at a typical Point +here say x = 3 y = 1 what let me draw + + align:start position:0% +here say x = 3 y = 1 what let me draw + + + align:start position:0% +here say x = 3 y = 1 what let me draw +the little arrow uh with a big chalk + + align:start position:0% +the little arrow uh with a big chalk + + + align:start position:0% +the little arrow uh with a big chalk +uh which way is the flow going well no + + align:start position:0% +uh which way is the flow going well no + + + align:start position:0% +uh which way is the flow going well no +flow if the X component is zero the Y + + align:start position:0% +flow if the X component is zero the Y + + + align:start position:0% +flow if the X component is zero the Y +component is X so if that so that the + + align:start position:0% +component is X so if that so that the + + + align:start position:0% +component is X so if that so that the +flow is going up there right + + align:start position:0% +flow is going up there right + + + align:start position:0% +flow is going up there right +here + + align:start position:0% +here + + + align:start position:0% +here +uh yeah here are the Y component is X + + align:start position:0% +uh yeah here are the Y component is X + + + align:start position:0% +uh yeah here are the Y component is X +this whole line is all traveling up with + + align:start position:0% +this whole line is all traveling up with + + + align:start position:0% +this whole line is all traveling up with +the same + + align:start position:0% +the same + + + align:start position:0% +the same +velocity if I drop a leaf there it + + align:start position:0% +velocity if I drop a leaf there it + + + align:start position:0% +velocity if I drop a leaf there it +buzzes up that straight line so that's + + align:start position:0% +buzzes up that straight line so that's + + + align:start position:0% +buzzes up that straight line so that's +the Streamline and uh it's velocity is + + align:start position:0% +the Streamline and uh it's velocity is + + + align:start position:0% +the Streamline and uh it's velocity is +uh if if that's x equal if say the + + align:start position:0% +uh if if that's x equal if say the + + + align:start position:0% +uh if if that's x equal if say the +velocity is three then these this this + + align:start position:0% +velocity is three then these this this + + + align:start position:0% +velocity is three then these this this +uh speed is three it's going up that + + align:start position:0% +uh speed is three it's going up that + + + align:start position:0% +uh speed is three it's going up that +line so that's a that's a streamline and + + align:start position:0% +line so that's a that's a streamline and + + + align:start position:0% +line so that's a that's a streamline and +sure enough on that line minus a half + + align:start position:0% +sure enough on that line minus a half + + + align:start position:0% +sure enough on that line minus a half +x^2 is a constant so you see it's we're + + align:start position:0% +x^2 is a constant so you see it's we're + + + align:start position:0% +x^2 is a constant so you see it's we're +not talking parabas here because we're + + align:start position:0% +not talking parabas here because we're + + + align:start position:0% +not talking parabas here because we're +not our our curve is not y equal - half + + align:start position:0% +not our our curve is not y equal - half + + + align:start position:0% +not our our curve is not y equal - half +x^2 it's - half x^2 equal constant yeah + + align:start position:0% +x^2 it's - half x^2 equal constant yeah + + + align:start position:0% +x^2 it's - half x^2 equal constant yeah +that's what we want so but now having + + align:start position:0% +that's what we want so but now having + + + align:start position:0% +that's what we want so but now having +got so far let me go let me take xal 1 + + align:start position:0% +got so far let me go let me take xal 1 + + + align:start position:0% +got so far let me go let me take xal 1 +say what what's the flow like on that so + + align:start position:0% +say what what's the flow like on that so + + + align:start position:0% +say what what's the flow like on that so +there's a streamline + + align:start position:0% +there's a streamline + + + align:start position:0% +there's a streamline +with s equal constant and the velocity + + align:start position:0% +with s equal constant and the velocity + + + align:start position:0% +with s equal constant and the velocity +on that is zero so nothing's going in + + align:start position:0% +on that is zero so nothing's going in + + + align:start position:0% +on that is zero so nothing's going in +the in in that horizontally and now it's + + align:start position:0% +the in in that horizontally and now it's + + + align:start position:0% +the in in that horizontally and now it's +one so these the flow is slower up this + + align:start position:0% +one so these the flow is slower up this + + + align:start position:0% +one so these the flow is slower up this +line + + align:start position:0% + + + + align:start position:0% + +okay slower flow this was faster flow + + align:start position:0% +okay slower flow this was faster flow + + + align:start position:0% +okay slower flow this was faster flow +and then the the question that's in that + + align:start position:0% +and then the the question that's in that + + + align:start position:0% +and then the the question that's in that +homework problem is is there any + + align:start position:0% +homework problem is is there any + + + align:start position:0% +homework problem is is there any +rotation in this flow + + align:start position:0% +rotation in this flow + + + align:start position:0% +rotation in this flow +you know we think about rotation we have + + align:start position:0% +you know we think about rotation we have + + + align:start position:0% +you know we think about rotation we have +an we have an image of rotational flow + + align:start position:0% +an we have an image of rotational flow + + + align:start position:0% +an we have an image of rotational flow +like in and that could be the next + + align:start position:0% +like in and that could be the next + + + align:start position:0% +like in and that could be the next +example we we could figure out what what + + align:start position:0% +example we we could figure out what what + + + align:start position:0% +example we we could figure out what what +a a flow that goes around in circles + + align:start position:0% +a a flow that goes around in circles + + + align:start position:0% +a a flow that goes around in circles +right we well those would be the + + align:start position:0% +right we well those would be the + + + align:start position:0% +right we well those would be the +streamlines so this would be like pure + + align:start position:0% +streamlines so this would be like pure + + + align:start position:0% +streamlines so this would be like pure +rotation shall I call it + + align:start position:0% + + + + align:start position:0% + +but I don't have that there I just want + + align:start position:0% +but I don't have that there I just want + + + align:start position:0% +but I don't have that there I just want +to draw the other picture in which the + + align:start position:0% +to draw the other picture in which the + + + align:start position:0% +to draw the other picture in which the +streamlines + + align:start position:0% +streamlines + + + align:start position:0% +streamlines +are circles + + align:start position:0% + + + + align:start position:0% + +to have another nice clean beautiful + + align:start position:0% +to have another nice clean beautiful + + + align:start position:0% +to have another nice clean beautiful +example okay but here we don't have our + + align:start position:0% +example okay but here we don't have our + + + align:start position:0% +example okay but here we don't have our +streamlines are straight lines and yet + + align:start position:0% +streamlines are straight lines and yet + + + align:start position:0% +streamlines are straight lines and yet +we have rotation that's the point here + + align:start position:0% +we have rotation that's the point here + + + align:start position:0% +we have rotation that's the point here +why do we have what's why do I say we + + align:start position:0% +why do we have what's why do I say we + + + align:start position:0% +why do we have what's why do I say we +have rotation because the test for + + align:start position:0% +have rotation because the test for + + + align:start position:0% +have rotation because the test for +rotation was that original test of + + align:start position:0% +rotation was that original test of + + + align:start position:0% +rotation was that original test of +looking that which I just wrote the + + align:start position:0% +looking that which I just wrote the + + + align:start position:0% +looking that which I just wrote the +answer to be no here + + align:start position:0% +answer to be no here + + + align:start position:0% +answer to be no here +it's not the great so if it's not the + + align:start position:0% +it's not the great so if it's not the + + + align:start position:0% +it's not the great so if it's not the +gradient the reason is there's some + + align:start position:0% +gradient the reason is there's some + + + align:start position:0% +gradient the reason is there's some +rotation gradient Fields don't have any + + align:start position:0% +rotation gradient Fields don't have any + + + align:start position:0% +rotation gradient Fields don't have any +rotation the the rotation is this is + + align:start position:0% +rotation the the rotation is this is + + + align:start position:0% +rotation the the rotation is this is +this uh du is this thing that comes out + + align:start position:0% +this uh du is this thing that comes out + + + align:start position:0% +this uh du is this thing that comes out +yeah it's this difference dv2 DX it's + + align:start position:0% +yeah it's this difference dv2 DX it's + + + align:start position:0% +yeah it's this difference dv2 DX it's +the difference between those that tells + + align:start position:0% +the difference between those that tells + + + align:start position:0% +the difference between those that tells +us the rotation and that was not zero + + align:start position:0% +us the rotation and that was not zero + + + align:start position:0% +us the rotation and that was not zero +right that for for this example dv1 Dy + + align:start position:0% +right that for for this example dv1 Dy + + + align:start position:0% +right that for for this example dv1 Dy +was Zero because V1 is zero dv2 DX was + + align:start position:0% +was Zero because V1 is zero dv2 DX was + + + align:start position:0% +was Zero because V1 is zero dv2 DX was +one because V2 is X so there's some + + align:start position:0% +one because V2 is X so there's some + + + align:start position:0% +one because V2 is X so there's some +rotation here and that's that's in other + + align:start position:0% +rotation here and that's that's in other + + + align:start position:0% +rotation here and that's that's in other +words the test being a gradient is no + + align:start position:0% +words the test being a gradient is no + + + align:start position:0% +words the test being a gradient is no +rotation this fails that test so but how + + align:start position:0% +rotation this fails that test so but how + + + align:start position:0% +rotation this fails that test so but how +is it rotating how how can it how can it + + align:start position:0% +is it rotating how how can it how can it + + + align:start position:0% +is it rotating how how can it how can it +be rotating when the all the flow is + + align:start position:0% +be rotating when the all the flow is + + + align:start position:0% +be rotating when the all the flow is +just traveling vertically do do you I I + + align:start position:0% +just traveling vertically do do you I I + + + align:start position:0% +just traveling vertically do do you I I +guess I give you this example because it + + align:start position:0% +guess I give you this example because it + + + align:start position:0% +guess I give you this example because it +meant something to me I didn't you know + + align:start position:0% +meant something to me I didn't you know + + + align:start position:0% +meant something to me I didn't you know +my image of rotation was this + + align:start position:0% +my image of rotation was this + + + align:start position:0% +my image of rotation was this +simple-minded type of flow you know like + + align:start position:0% +simple-minded type of flow you know like + + + align:start position:0% +simple-minded type of flow you know like +a phonograph record or something this + + align:start position:0% +a phonograph record or something this + + + align:start position:0% +a phonograph record or something this +would be called a sheer flow and there's + + align:start position:0% +would be called a sheer flow and there's + + + align:start position:0% +would be called a sheer flow and there's +a very important type of flow + + align:start position:0% +a very important type of flow + + + align:start position:0% +a very important type of flow +and and actually you you realize that if + + align:start position:0% +and and actually you you realize that if + + + align:start position:0% +and and actually you you realize that if +if x is negative then the the flow in + + align:start position:0% +if x is negative then the the flow in + + + align:start position:0% +if x is negative then the the flow in +the the second component of the Velocity + + align:start position:0% +the the second component of the Velocity + + + align:start position:0% +the the second component of the Velocity +is now negative so it would be the + + align:start position:0% +is now negative so it would be the + + + align:start position:0% +is now negative so it would be the +Streamline the flow would be going down + + align:start position:0% +Streamline the flow would be going down + + + align:start position:0% +Streamline the flow would be going down +this way and this point wouldn't move at + + align:start position:0% +this way and this point wouldn't move at + + + align:start position:0% +this way and this point wouldn't move at +all these guy this would be well I don't + + align:start position:0% +all these guy this would be well I don't + + + align:start position:0% +all these guy this would be well I don't +know if it's a streamline it's a + + align:start position:0% +know if it's a streamline it's a + + + align:start position:0% +know if it's a streamline it's a +stagnant streamline right x equal x + + align:start position:0% +stagnant streamline right x equal x + + + align:start position:0% +stagnant streamline right x equal x +equals z on that line there's no + + align:start position:0% +equals z on that line there's no + + + align:start position:0% +equals z on that line there's no +velocity z0 so this is this is all just + + align:start position:0% +velocity z0 so this is this is all just + + + align:start position:0% +velocity z0 so this is this is all just +staying there these lines are moving + + align:start position:0% +staying there these lines are moving + + + align:start position:0% +staying there these lines are moving +this Line's moving faster this line will + + align:start position:0% +this Line's moving faster this line will + + + align:start position:0% +this Line's moving faster this line will +be moving even faster this Line's going + + align:start position:0% +be moving even faster this Line's going + + + align:start position:0% +be moving even faster this Line's going +the other way + + align:start position:0% +the other way + + + align:start position:0% +the other way +faster and faster the other way it's a + + align:start position:0% +faster and faster the other way it's a + + + align:start position:0% +faster and faster the other way it's a +important flow you know in in + + align:start position:0% +important flow you know in in + + + align:start position:0% +important flow you know in in +earthquakes and things like that this + + align:start position:0% +earthquakes and things like that this + + + align:start position:0% +earthquakes and things like that this +this is this happens when one plate + + align:start position:0% +this is this happens when one plate + + + align:start position:0% +this is this happens when one plate +shears with respect to another + + align:start position:0% +shears with respect to another + + + align:start position:0% +shears with respect to another +so that's shear ing shearing is that + + align:start position:0% +so that's shear ing shearing is that + + + align:start position:0% +so that's shear ing shearing is that +that word shearing means that that the a + + align:start position:0% +that word shearing means that that the a + + + align:start position:0% +that word shearing means that that the a +line that was you know that line after a + + align:start position:0% +line that was you know that line after a + + + align:start position:0% +line that was you know that line after a +while is tilted yeah th this is going + + align:start position:0% +while is tilted yeah th this is going + + + align:start position:0% +while is tilted yeah th this is going +faster than this yes + + align:start position:0% + + + + align:start position:0% + +right being a constant + + align:start position:0% + + + + align:start position:0% + +uh that's true + + align:start position:0% +uh that's true + + + align:start position:0% +uh that's true +ah well okay uh let's see + + align:start position:0% +ah well okay uh let's see + + + align:start position:0% +ah well okay uh let's see +yeah what okay well how do I fix that + + align:start position:0% + + + + align:start position:0% + +yes yeah so that's a good question + + align:start position:0% +yes yeah so that's a good question + + + align:start position:0% +yes yeah so that's a good question +should I have allowed + + align:start position:0% +should I have allowed + + + align:start position:0% +should I have allowed +in my stream function + + align:start position:0% +in my stream function + + + align:start position:0% +in my stream function +I mean that's a stream function because + + align:start position:0% +I mean that's a stream function because + + + align:start position:0% +I mean that's a stream function because +it satisfies the equations that stream + + align:start position:0% +it satisfies the equations that stream + + + align:start position:0% +it satisfies the equations that stream +functions are so I could have thrown in + + align:start position:0% +functions are so I could have thrown in + + + align:start position:0% +functions are so I could have thrown in +a constant yeah so you're pointing out a + + align:start position:0% +a constant yeah so you're pointing out a + + + align:start position:0% +a constant yeah so you're pointing out a +difficulty makes me think I should have + + align:start position:0% +difficulty makes me think I should have + + + align:start position:0% +difficulty makes me think I should have +thrown in a constant yeah yeah so if I + + align:start position:0% +thrown in a constant yeah yeah so if I + + + align:start position:0% +thrown in a constant yeah yeah so if I +throw in constants then I could get + + align:start position:0% +throw in constants then I could get + + + align:start position:0% +throw in constants then I could get +other lines yeah yeah thanks that's a + + align:start position:0% +other lines yeah yeah thanks that's a + + + align:start position:0% +other lines yeah yeah thanks that's a +good point I just want to see do you see + + align:start position:0% +good point I just want to see do you see + + + align:start position:0% +good point I just want to see do you see +rotation in this flow in this sheer flow + + align:start position:0% +rotation in this flow in this sheer flow + + + align:start position:0% +rotation in this flow in this sheer flow +and I think you do if you think about it + + align:start position:0% +and I think you do if you think about it + + + align:start position:0% +and I think you do if you think about it +suppose you put a little leaf or a or a + + align:start position:0% +suppose you put a little leaf or a or a + + + align:start position:0% +suppose you put a little leaf or a or a +little Penny or something right there + + align:start position:0% +little Penny or something right there + + + align:start position:0% +little Penny or something right there +okay is it going to turn it'll flow + + align:start position:0% +okay is it going to turn it'll flow + + + align:start position:0% +okay is it going to turn it'll flow +along but as it flows + + align:start position:0% +along but as it flows + + + align:start position:0% +along but as it flows +is it going to turn in other words is + + align:start position:0% +is it going to turn in other words is + + + align:start position:0% +is it going to turn in other words is +there some + + align:start position:0% +there some + + + align:start position:0% +there some +uh is there some difference in the in + + align:start position:0% +uh is there some difference in the in + + + align:start position:0% +uh is there some difference in the in +the um speed on one side compared to the + + align:start position:0% +the um speed on one side compared to the + + + align:start position:0% +the um speed on one side compared to the +other I mean it's what makes a curveball + + align:start position:0% +other I mean it's what makes a curveball + + + align:start position:0% +other I mean it's what makes a curveball +curve right you when the pitcher throws + + align:start position:0% +curve right you when the pitcher throws + + + align:start position:0% +curve right you when the pitcher throws +the ball he imparts a spin to it and + + align:start position:0% +the ball he imparts a spin to it and + + + align:start position:0% +the ball he imparts a spin to it and +that and that gives a different pressure + + align:start position:0% +that and that gives a different pressure + + + align:start position:0% +that and that gives a different pressure +on the two sides of the ball and it + + align:start position:0% +on the two sides of the ball and it + + + align:start position:0% +on the two sides of the ball and it +moves the ball moves okay I think that's + + align:start position:0% +moves the ball moves okay I think that's + + + align:start position:0% +moves the ball moves okay I think that's +going to happen here + + align:start position:0% +going to happen here + + + align:start position:0% +going to happen here +maybe you see it and I'm just talking uh + + align:start position:0% +maybe you see it and I'm just talking uh + + + align:start position:0% +maybe you see it and I'm just talking uh +I mean this side is going faster than + + align:start position:0% +I mean this side is going faster than + + + align:start position:0% +I mean this side is going faster than +this side so the net result is that that + + align:start position:0% +this side so the net result is that that + + + align:start position:0% +this side so the net result is that that +even though the the thing is traveling + + align:start position:0% +even though the the thing is traveling + + + align:start position:0% +even though the the thing is traveling +up and down it's + + align:start position:0% +up and down it's + + + align:start position:0% +up and down it's +turning it's it's turning because the + + align:start position:0% +turning it's it's turning because the + + + align:start position:0% +turning it's it's turning because the +right hand side is is going faster than + + align:start position:0% +right hand side is is going faster than + + + align:start position:0% +right hand side is is going faster than +the left hand side so it has a it does + + align:start position:0% +the left hand side so it has a it does + + + align:start position:0% +the left hand side so it has a it does +have a rotation this this quantity this + + align:start position:0% +have a rotation this this quantity this + + + align:start position:0% +have a rotation this this quantity this +difference between dv1 Dy and dv2 DX + + align:start position:0% +difference between dv1 Dy and dv2 DX + + + align:start position:0% +difference between dv1 Dy and dv2 DX +which is is the component of the curl + + align:start position:0% +which is is the component of the curl + + + align:start position:0% +which is is the component of the curl +maybe the sign it should be the opposite + + align:start position:0% +maybe the sign it should be the opposite + + + align:start position:0% +maybe the sign it should be the opposite +maybe I think it should be minus this + + align:start position:0% +maybe I think it should be minus this + + + align:start position:0% +maybe I think it should be minus this +plus this or something point is that + + align:start position:0% +plus this or something point is that + + + align:start position:0% +plus this or something point is that +it's not zero so there is curl there is + + align:start position:0% +it's not zero so there is curl there is + + + align:start position:0% +it's not zero so there is curl there is +rotation okay I was going to ask about + + align:start position:0% +rotation okay I was going to ask about + + + align:start position:0% +rotation okay I was going to ask about +this picture too but then and then I'll + + align:start position:0% +this picture too but then and then I'll + + + align:start position:0% +this picture too but then and then I'll +open to more examples I I I just feel + + align:start position:0% +open to more examples I I I just feel + + + align:start position:0% +open to more examples I I I just feel +examples are good simple velocity Fields + + align:start position:0% +examples are good simple velocity Fields + + + align:start position:0% +examples are good simple velocity Fields +like 0x + + align:start position:0% +like 0x + + + align:start position:0% +like 0x +uh just to Think Through okay what does + + align:start position:0% +uh just to Think Through okay what does + + + align:start position:0% +uh just to Think Through okay what does +that mean what's the does is it curlf + + align:start position:0% +that mean what's the does is it curlf + + + align:start position:0% +that mean what's the does is it curlf +free another way of saying is it a + + align:start position:0% +free another way of saying is it a + + + align:start position:0% +free another way of saying is it a +gradient field would be to say is it + + align:start position:0% +gradient field would be to say is it + + + align:start position:0% +gradient field would be to say is it +curlf free rot not irrotational is the + + align:start position:0% +curlf free rot not irrotational is the + + + align:start position:0% +curlf free rot not irrotational is the +right word here test one is it + + align:start position:0% +right word here test one is it + + + align:start position:0% +right word here test one is it +irrotational answer no is it Divergence + + align:start position:0% +irrotational answer no is it Divergence + + + align:start position:0% +irrotational answer no is it Divergence +free is it Source free answer was yes + + align:start position:0% +free is it Source free answer was yes + + + align:start position:0% +free is it Source free answer was yes +for this example if we pick another + + align:start position:0% +for this example if we pick another + + + align:start position:0% +for this example if we pick another +example I could reverse those or another + + align:start position:0% +example I could reverse those or another + + + align:start position:0% +example I could reverse those or another +example I can probably come up with an + + align:start position:0% +example I can probably come up with an + + + align:start position:0% +example I can probably come up with an +example here let's see what what should + + align:start position:0% +example here let's see what what should + + + align:start position:0% +example here let's see what what should +be the if I wanted the streamlines to be + + align:start position:0% +be the if I wanted the streamlines to be + + + align:start position:0% +be the if I wanted the streamlines to be +circles what would be a good velocity + + align:start position:0% +circles what would be a good velocity + + + align:start position:0% +circles what would be a good velocity +field that goes in circles + + align:start position:0% + + + + align:start position:0% + +let's see at a typical point + + align:start position:0% +let's see at a typical point + + + align:start position:0% +let's see at a typical point +if I want the velocity to be going that + + align:start position:0% +if I want the velocity to be going that + + + align:start position:0% +if I want the velocity to be going that +way here's the here's the vector the + + align:start position:0% +way here's the here's the vector the + + + align:start position:0% +way here's the here's the vector the +position Vector the radius Vector that + + align:start position:0% +position Vector the radius Vector that + + + align:start position:0% +position Vector the radius Vector that +goes so what are the components of this + + align:start position:0% +goes so what are the components of this + + + align:start position:0% +goes so what are the components of this +Vector just XY + + align:start position:0% +Vector just XY + + + align:start position:0% +Vector just XY +so now if I want the velocity field to + + align:start position:0% +so now if I want the velocity field to + + + align:start position:0% +so now if I want the velocity field to +go + + align:start position:0% +go + + + align:start position:0% +go +other way which what would be a good Vel + + align:start position:0% +other way which what would be a good Vel + + + align:start position:0% +other way which what would be a good Vel +what would be a good thing with + + align:start position:0% +what would be a good thing with + + + align:start position:0% +what would be a good thing with +with rotation + + align:start position:0% +with rotation + + + align:start position:0% +with rotation +minus YX would sound good V equal minus + + align:start position:0% +minus YX would sound good V equal minus + + + align:start position:0% +minus YX would sound good V equal minus +YX + + align:start position:0% +YX + + + align:start position:0% +YX +so are we expecting this to be a + + align:start position:0% +so are we expecting this to be a + + + align:start position:0% +so are we expecting this to be a +gradient of anything + + align:start position:0% +gradient of anything + + + align:start position:0% +gradient of anything +I'm not + + align:start position:0% +I'm not + + + align:start position:0% +I'm not +this is uh we've built in rotation here + + align:start position:0% +this is uh we've built in rotation here + + + align:start position:0% +this is uh we've built in rotation here +I'm expecting the curl of this thing + + align:start position:0% +I'm expecting the curl of this thing + + + align:start position:0% +I'm expecting the curl of this thing +this quantity I think it's I take the X + + align:start position:0% +this quantity I think it's I take the X + + + align:start position:0% +this quantity I think it's I take the X +derivative I take the X derivative of I + + align:start position:0% +derivative I take the X derivative of I + + + align:start position:0% +derivative I take the X derivative of I +I look at the the Y derivative of this + + align:start position:0% +I look at the the Y derivative of this + + + align:start position:0% +I look at the the Y derivative of this +and compare it with the X derivative of + + align:start position:0% +and compare it with the X derivative of + + + align:start position:0% +and compare it with the X derivative of +that and they're not the same in fact + + align:start position:0% +that and they're not the same in fact + + + align:start position:0% +that and they're not the same in fact +one is minus one and the other is plus + + align:start position:0% +one is minus one and the other is plus + + + align:start position:0% +one is minus one and the other is plus +one so I've got rotation here I've got + + align:start position:0% +one so I've got rotation here I've got + + + align:start position:0% +one so I've got rotation here I've got +sort of two is the the the the the + + align:start position:0% +sort of two is the the the the the + + + align:start position:0% +sort of two is the the the the the +measure of is is that component of the + + align:start position:0% +measure of is is that component of the + + + align:start position:0% +measure of is is that component of the +curl so so let me let's just write it + + align:start position:0% +curl so so let me let's just write it + + + align:start position:0% +curl so so let me let's just write it +down dv2 DX + + align:start position:0% + + + + align:start position:0% + +this vorticity + + align:start position:0% +this vorticity + + + align:start position:0% +this vorticity +that that measures the Turning speed is + + align:start position:0% +that that measures the Turning speed is + + + align:start position:0% +that that measures the Turning speed is +1 from dv2 DX minus minus one is 2 + + align:start position:0% +1 from dv2 DX minus minus one is 2 + + + align:start position:0% +1 from dv2 DX minus minus one is 2 +so it's not a gradient of anything + + align:start position:0% +so it's not a gradient of anything + + + align:start position:0% +so it's not a gradient of anything +if the X derivative of U is minus y then + + align:start position:0% +if the X derivative of U is minus y then + + + align:start position:0% +if the X derivative of U is minus y then +the Y derivative can't be plus x no good + + align:start position:0% +the Y derivative can't be plus x no good + + + align:start position:0% +the Y derivative can't be plus x no good +okay what about does it have is it + + align:start position:0% +okay what about does it have is it + + + align:start position:0% +okay what about does it have is it +Divergence free is it is it do I need a + + align:start position:0% +Divergence free is it is it do I need a + + + align:start position:0% +Divergence free is it is it do I need a +source to keep this flow going well + + align:start position:0% +source to keep this flow going well + + + align:start position:0% +source to keep this flow going well +what's the test in other words is there + + align:start position:0% +what's the test in other words is there + + + align:start position:0% +what's the test in other words is there +a stream function for this guy + + align:start position:0% +a stream function for this guy + + + align:start position:0% +a stream function for this guy +I I think probably there is + + align:start position:0% +I I think probably there is + + + align:start position:0% +I I think probably there is +what's the test to to know if there is a + + align:start position:0% +what's the test to to know if there is a + + + align:start position:0% +what's the test to to know if there is a +stream function I take the Divergence + + align:start position:0% +stream function I take the Divergence + + + align:start position:0% +stream function I take the Divergence +I'm over on the right hand side of my my + + align:start position:0% +I'm over on the right hand side of my my + + + align:start position:0% +I'm over on the right hand side of my my +picture now I take the Divergence + + align:start position:0% +picture now I take the Divergence + + + align:start position:0% +picture now I take the Divergence +Divergence of this V is the X derivative + + align:start position:0% +Divergence of this V is the X derivative + + + align:start position:0% +Divergence of this V is the X derivative +of that plus the Y derivative of that + + align:start position:0% +of that plus the Y derivative of that + + + align:start position:0% +of that plus the Y derivative of that +good zero so there is a stream function + + align:start position:0% +good zero so there is a stream function + + + align:start position:0% +good zero so there is a stream function +and what is it + + align:start position:0% +and what is it + + + align:start position:0% +and what is it +well I'm pretty darn sure that the these + + align:start position:0% +well I'm pretty darn sure that the these + + + align:start position:0% +well I'm pretty darn sure that the these +stream lines are circles I think the + + align:start position:0% +stream lines are circles I think the + + + align:start position:0% +stream lines are circles I think the +stream function is going to be X2 + y^2 + + align:start position:0% +stream function is going to be X2 + y^2 + + + align:start position:0% +stream function is going to be X2 + y^2 +yeah yeah + + align:start position:0% +yeah yeah + + + align:start position:0% +yeah yeah +then am I right that the Y derivative of + + align:start position:0% +then am I right that the Y derivative of + + + align:start position:0% +then am I right that the Y derivative of +that will be 2x sorry the Y derivative + + align:start position:0% +that will be 2x sorry the Y derivative + + + align:start position:0% +that will be 2x sorry the Y derivative +of that will be 2 y who it's not not + + align:start position:0% +of that will be 2 y who it's not not + + + align:start position:0% +of that will be 2 y who it's not not +looking too good what do I want here + + align:start position:0% +looking too good what do I want here + + + align:start position:0% +looking too good what do I want here +here's my V which is the same as W and + + align:start position:0% +here's my V which is the same as W and + + + align:start position:0% +here's my V which is the same as W and +what I'm looking for is to get these + + align:start position:0% +what I'm looking for is to get these + + + align:start position:0% +what I'm looking for is to get these +guys correct so so and I'm should be + + align:start position:0% +guys correct so so and I'm should be + + + align:start position:0% +guys correct so so and I'm should be +able to do it and what What Would S be I + + align:start position:0% +able to do it and what What Would S be I + + + align:start position:0% +able to do it and what What Would S be I +haven't got s quite right + + align:start position:0% +haven't got s quite right + + + align:start position:0% +haven't got s quite right +I think if I multiply by negative a half + + align:start position:0% +I think if I multiply by negative a half + + + align:start position:0% +I think if I multiply by negative a half +that might have done it yeah because now + + align:start position:0% +that might have done it yeah because now + + + align:start position:0% +that might have done it yeah because now +the Y derivative is now + + align:start position:0% +the Y derivative is now + + + align:start position:0% +the Y derivative is now +minus y great and the X derivative of s + + align:start position:0% +minus y great and the X derivative of s + + + align:start position:0% +minus y great and the X derivative of s +is min - x and then I should take a + + align:start position:0% +is min - x and then I should take a + + + align:start position:0% +is min - x and then I should take a +minus that so I should want a plus X + + align:start position:0% +minus that so I should want a plus X + + + align:start position:0% +minus that so I should want a plus X +which is what I've got yeah so those are + + align:start position:0% +which is what I've got yeah so those are + + + align:start position:0% +which is what I've got yeah so those are +the streamlines C CES + + align:start position:0% +the streamlines C CES + + + align:start position:0% +the streamlines C CES +so I have Circle the flow is going + + align:start position:0% +so I have Circle the flow is going + + + align:start position:0% +so I have Circle the flow is going +around in a circle + + align:start position:0% +around in a circle + + + align:start position:0% +around in a circle +I don't have to I don't need any source + + align:start position:0% +I don't have to I don't need any source + + + align:start position:0% +I don't have to I don't need any source +to keep it going + + align:start position:0% +to keep it going + + + align:start position:0% +to keep it going +but it's not uh it's not a gradient + + align:start position:0% +but it's not uh it's not a gradient + + + align:start position:0% +but it's not uh it's not a gradient +field right it's not it's not a gradient + + align:start position:0% +field right it's not it's not a gradient + + + align:start position:0% +field right it's not it's not a gradient +field so those are the this is like + + align:start position:0% +field so those are the this is like + + + align:start position:0% +field so those are the this is like +sample tests to to take a a simple flow + + align:start position:0% +sample tests to to take a a simple flow + + + align:start position:0% +sample tests to to take a a simple flow +field apply the two tests and I guess we + + align:start position:0% +field apply the two tests and I guess we + + + align:start position:0% +field apply the two tests and I guess we +should complete with an example that + + align:start position:0% +should complete with an example that + + + align:start position:0% +should complete with an example that +passes both tests + + align:start position:0% +passes both tests + + + align:start position:0% +passes both tests +right un this let me open to any other + + align:start position:0% +right un this let me open to any other + + + align:start position:0% +right un this let me open to any other +question and then I'll we could cook up + + align:start position:0% +question and then I'll we could cook up + + + align:start position:0% +question and then I'll we could cook up +an example that passes both tests before + + align:start position:0% +an example that passes both tests before + + + align:start position:0% +an example that passes both tests before +we stop I'll stop talking first though + + align:start position:0% +we stop I'll stop talking first though + + + align:start position:0% +we stop I'll stop talking first though +and just listen for a question on any + + align:start position:0% +and just listen for a question on any + + + align:start position:0% +and just listen for a question on any +topic or or is it useful just to take + + align:start position:0% +topic or or is it useful just to take + + + align:start position:0% +topic or or is it useful just to take +Fields like this and go through those + + align:start position:0% +Fields like this and go through those + + + align:start position:0% +Fields like this and go through those +steps to probably is certainly good for + + align:start position:0% +steps to probably is certainly good for + + + align:start position:0% +steps to probably is certainly good for +me + + align:start position:0% +me + + + align:start position:0% +me +okay what's a field that will satisfy + + align:start position:0% +okay what's a field that will satisfy + + + align:start position:0% +okay what's a field that will satisfy +everybody that will be a gradient field + + align:start position:0% +everybody that will be a gradient field + + + align:start position:0% +everybody that will be a gradient field +and also Divergence free so that it'll + + align:start position:0% +and also Divergence free so that it'll + + + align:start position:0% +and also Divergence free so that it'll +be a it'll we'll have solution to llaus + + align:start position:0% +be a it'll we'll have solution to llaus + + + align:start position:0% +be a it'll we'll have solution to llaus +equation + + align:start position:0% +equation + + + align:start position:0% +equation +uh let's see well we had some solutions + + align:start position:0% +uh let's see well we had some solutions + + + align:start position:0% +uh let's see well we had some solutions +to lus equation + + align:start position:0% +to lus equation + + + align:start position:0% +to lus equation +there how do we get yeah do want + + align:start position:0% +there how do we get yeah do want + + + align:start position:0% +there how do we get yeah do want +you know if I make it linear it's real + + align:start position:0% +you know if I make it linear it's real + + + align:start position:0% +you know if I make it linear it's real +easy + + align:start position:0% +easy + + + align:start position:0% +easy +should I if I make it quadratic we huh + + align:start position:0% +should I if I make it quadratic we huh + + + align:start position:0% +should I if I make it quadratic we huh +let me + + align:start position:0% + + + + align:start position:0% + +can can I anticipate a little what's + + align:start position:0% +can can I anticipate a little what's + + + align:start position:0% +can can I anticipate a little what's +coming Friday + + align:start position:0% +coming Friday + + + align:start position:0% +coming Friday +I I still recommend to come to Friday's + + align:start position:0% +I I still recommend to come to Friday's + + + align:start position:0% +I I still recommend to come to Friday's +lecture but uh here here so what's + + align:start position:0% +lecture but uh here here so what's + + + align:start position:0% +lecture but uh here here so what's +coming what did we do today we + + align:start position:0% +coming what did we do today we + + + align:start position:0% +coming what did we do today we +discovered that we got solutions to the + + align:start position:0% +discovered that we got solutions to the + + + align:start position:0% +discovered that we got solutions to the +ples equation from all by real and + + align:start position:0% +ples equation from all by real and + + + align:start position:0% +ples equation from all by real and +imaginary parts of all these guys th + + align:start position:0% +imaginary parts of all these guys th + + + align:start position:0% +imaginary parts of all these guys th +those were terrific + + align:start position:0% +those were terrific + + + align:start position:0% +those were terrific +and then we could take combinations of + + align:start position:0% +and then we could take combinations of + + + align:start position:0% +and then we could take combinations of +those so here's what's coming Friday + + align:start position:0% +those so here's what's coming Friday + + + align:start position:0% +those so here's what's coming Friday +when I take combinations of these guys + + align:start position:0% +when I take combinations of these guys + + + align:start position:0% +when I take combinations of these guys +I get some some function of this magic + + align:start position:0% +I get some some function of this magic + + + align:start position:0% +I get some some function of this magic +complex + + align:start position:0% +complex + + + align:start position:0% +complex +of this magic combination X Plus i y + + align:start position:0% +of this magic combination X Plus i y + + + align:start position:0% +of this magic combination X Plus i y +some function any function any + + align:start position:0% +some function any function any + + + align:start position:0% +some function any function any +reasonable function and we'll say what + + align:start position:0% +reasonable function and we'll say what + + + align:start position:0% +reasonable function and we'll say what +reasonable means of X Plus i y its real + + align:start position:0% +reasonable means of X Plus i y its real + + + align:start position:0% +reasonable means of X Plus i y its real +part and its imaginary part are going to + + align:start position:0% +part and its imaginary part are going to + + + align:start position:0% +part and its imaginary part are going to +be great this is like the center of a + + align:start position:0% +be great this is like the center of a + + + align:start position:0% +be great this is like the center of a +big big part of mathematics functions of + + align:start position:0% +big big part of mathematics functions of + + + align:start position:0% +big big part of mathematics functions of +X Plus i y + + align:start position:0% +X Plus i y + + + align:start position:0% +X Plus i y +and I if by nice I mean that there these + + align:start position:0% +and I if by nice I mean that there these + + + align:start position:0% +and I if by nice I mean that there these +series converge so that we have really a + + align:start position:0% +series converge so that we have really a + + + align:start position:0% +series converge so that we have really a +nice function let me take the first + + align:start position:0% +nice function let me take the first + + + align:start position:0% +nice function let me take the first +function that comes to mind e to the X + + align:start position:0% +function that comes to mind e to the X + + + align:start position:0% +function that comes to mind e to the X +Plus iy so so let me let me take this to + + align:start position:0% +Plus iy so so let me let me take this to + + + align:start position:0% +Plus iy so so let me let me take this to +be e to the x + i y + + align:start position:0% +be e to the x + i y + + + align:start position:0% +be e to the x + i y +okay + + align:start position:0% +okay + + + align:start position:0% +okay +all right so you remember I'm aiming to + + align:start position:0% +all right so you remember I'm aiming to + + + align:start position:0% +all right so you remember I'm aiming to +get solutions to the ples equation + + align:start position:0% +get solutions to the ples equation + + + align:start position:0% +get solutions to the ples equation +because that will give me automatically + + align:start position:0% +because that will give me automatically + + + align:start position:0% +because that will give me automatically +the two pieces both working so I claim + + align:start position:0% +the two pieces both working so I claim + + + align:start position:0% +the two pieces both working so I claim +that the real part of that and the + + align:start position:0% +that the real part of that and the + + + align:start position:0% +that the real part of that and the +imagin part those are my twins U and S + + align:start position:0% +imagin part those are my twins U and S + + + align:start position:0% +imagin part those are my twins U and S +both solve so U is going to be the real + + align:start position:0% +both solve so U is going to be the real + + + align:start position:0% +both solve so U is going to be the real +part of this function and S is going to + + align:start position:0% +part of this function and S is going to + + + align:start position:0% +part of this function and S is going to +be the imaginary part of it and I claim + + align:start position:0% +be the imaginary part of it and I claim + + + align:start position:0% +be the imaginary part of it and I claim +that those will both solve theosis + + align:start position:0% +that those will both solve theosis + + + align:start position:0% +that those will both solve theosis +equation we can plug it in and see that + + align:start position:0% +equation we can plug it in and see that + + + align:start position:0% +equation we can plug it in and see that +it does and that they will have they'll + + align:start position:0% +it does and that they will have they'll + + + align:start position:0% +it does and that they will have they'll +they'll they're twinned by the Koshi + + align:start position:0% +they'll they're twinned by the Koshi + + + align:start position:0% +they'll they're twinned by the Koshi +remon equations so how am I going to + + align:start position:0% +remon equations so how am I going to + + + align:start position:0% +remon equations so how am I going to +simplify that so that I can identify the + + align:start position:0% +simplify that so that I can identify the + + + align:start position:0% +simplify that so that I can identify the +what's the real part of that thing and + + align:start position:0% +what's the real part of that thing and + + + align:start position:0% +what's the real part of that thing and +what's the imaginary part this is + + align:start position:0% +what's the imaginary part this is + + + align:start position:0% +what's the imaginary part this is +actually that's a good question question + + align:start position:0% +actually that's a good question question + + + align:start position:0% +actually that's a good question question +do you we I don't know how many how much + + align:start position:0% +do you we I don't know how many how much + + + align:start position:0% +do you we I don't know how many how much +you've run into I in the past are you + + align:start position:0% +you've run into I in the past are you + + + align:start position:0% +you've run into I in the past are you +happy with + + align:start position:0% +happy with + + + align:start position:0% +happy with +something like that how could you find + + align:start position:0% +something like that how could you find + + + align:start position:0% +something like that how could you find +the real part of it how could you + + align:start position:0% +the real part of it how could you + + + align:start position:0% +the real part of it how could you +simplify it how else could I write e to + + align:start position:0% +simplify it how else could I write e to + + + align:start position:0% +simplify it how else could I write e to +the something + + align:start position:0% + + + + align:start position:0% + +what + + align:start position:0% +what + + + align:start position:0% +what +I exactly right it think of it as the + + align:start position:0% +I exactly right it think of it as the + + + align:start position:0% +I exactly right it think of it as the +product of two so the key fact about + + align:start position:0% +product of two so the key fact about + + + align:start position:0% +product of two so the key fact about +exponentials is that that's the same as + + align:start position:0% +exponentials is that that's the same as + + + align:start position:0% +exponentials is that that's the same as +e to the x * e to the i y right that's + + align:start position:0% +e to the x * e to the i y right that's + + + align:start position:0% +e to the x * e to the i y right that's +the exponents add so that's the first + + align:start position:0% +the exponents add so that's the first + + + align:start position:0% +the exponents add so that's the first +thing always to think about as a + + align:start position:0% +thing always to think about as a + + + align:start position:0% +thing always to think about as a +possibility now what am I going to do I + + align:start position:0% +possibility now what am I going to do I + + + align:start position:0% +possibility now what am I going to do I +still want to get a real part this is + + align:start position:0% +still want to get a real part this is + + + align:start position:0% +still want to get a real part this is +clearly all real right e to the x is + + align:start position:0% +clearly all real right e to the x is + + + align:start position:0% +clearly all real right e to the x is +real so it's it's this part that's got + + align:start position:0% +real so it's it's this part that's got + + + align:start position:0% +real so it's it's this part that's got +it's going to give me the two pieces so + + align:start position:0% +it's going to give me the two pieces so + + + align:start position:0% +it's going to give me the two pieces so +it's going to be e to the x times now + + align:start position:0% +it's going to be e to the x times now + + + align:start position:0% +it's going to be e to the x times now +what is what do I put for e to the i y + + align:start position:0% +what is what do I put for e to the i y + + + align:start position:0% +what is what do I put for e to the i y +y cos y good + + align:start position:0% +y cos y good + + + align:start position:0% +y cos y good +plus I sin y good and now I can read off + + align:start position:0% +plus I sin y good and now I can read off + + + align:start position:0% +plus I sin y good and now I can read off +no problem what is this real part that I + + align:start position:0% +no problem what is this real part that I + + + align:start position:0% +no problem what is this real part that I +was looking for + + align:start position:0% + + + + align:start position:0% + +E to X cos Y + + align:start position:0% + + + + align:start position:0% + +and the imaginary part is just the + + align:start position:0% +and the imaginary part is just the + + + align:start position:0% +and the imaginary part is just the +what's multiplying the I it's the e to + + align:start position:0% +what's multiplying the I it's the e to + + + align:start position:0% +what's multiplying the I it's the e to +the X sin y + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so what's my claim I claim that that + + align:start position:0% +so what's my claim I claim that that + + + align:start position:0% +so what's my claim I claim that that +function solves the ploes equation + + align:start position:0% +function solves the ploes equation + + + align:start position:0% +function solves the ploes equation +and this one too + + align:start position:0% +and this one too + + + align:start position:0% +and this one too +and that they're twinned and that + + align:start position:0% +and that they're twinned and that + + + align:start position:0% +and that they're twinned and that +they're they give streamlines and equip + + align:start position:0% +they're they give streamlines and equip + + + align:start position:0% +they're they give streamlines and equip +potentials that meet at right angles + + align:start position:0% +potentials that meet at right angles + + + align:start position:0% +potentials that meet at right angles +it's it's uh another another pair + + align:start position:0% +it's it's uh another another pair + + + align:start position:0% +it's it's uh another another pair +uh can we plug that into ll's equation + + align:start position:0% +uh can we plug that into ll's equation + + + align:start position:0% +uh can we plug that into ll's equation +so that's so let me do uxx X Plus uy y + + align:start position:0% +so that's so let me do uxx X Plus uy y + + + align:start position:0% +so that's so let me do uxx X Plus uy y +just to satisfy that it is going to come + + align:start position:0% +just to satisfy that it is going to come + + + align:start position:0% +just to satisfy that it is going to come +out zero so what's the XX derivative the + + align:start position:0% +out zero so what's the XX derivative the + + + align:start position:0% +out zero so what's the XX derivative the +second X derivative of that function + + align:start position:0% +second X derivative of that function + + + align:start position:0% +second X derivative of that function +say take its derivative respect to X and + + align:start position:0% +say take its derivative respect to X and + + + align:start position:0% +say take its derivative respect to X and +then do it again and what do you have + + align:start position:0% +then do it again and what do you have + + + align:start position:0% +then do it again and what do you have +same didn't change e to the x is just + + align:start position:0% +same didn't change e to the x is just + + + align:start position:0% +same didn't change e to the x is just +and and now what about the second y + + align:start position:0% +and and now what about the second y + + + align:start position:0% +and and now what about the second y +derivative + + align:start position:0% +derivative + + + align:start position:0% +derivative +so now e to the x is just a constant + + align:start position:0% +so now e to the x is just a constant + + + align:start position:0% +so now e to the x is just a constant +what's the second derivative of cos y + + align:start position:0% +what's the second derivative of cos y + + + align:start position:0% +what's the second derivative of cos y +negative cos y right because the first + + align:start position:0% +negative cos y right because the first + + + align:start position:0% +negative cos y right because the first +derivative is negative s and the second + + align:start position:0% +derivative is negative s and the second + + + align:start position:0% +derivative is negative s and the second +derivative is negative cosine so it's + + align:start position:0% +derivative is negative cosine so it's + + + align:start position:0% +derivative is negative cosine so it's +the second derivative is this e to the x + + align:start position:0% +the second derivative is this e to the x + + + align:start position:0% +the second derivative is this e to the x +that didn't change times cos y with the + + align:start position:0% +that didn't change times cos y with the + + + align:start position:0% +that didn't change times cos y with the +minus sign and you see what what + + align:start position:0% +minus sign and you see what what + + + align:start position:0% +minus sign and you see what what +did I write S I meant to write cosine + + align:start position:0% +did I write S I meant to write cosine + + + align:start position:0% +did I write S I meant to write cosine +cancel that from the tape okay right + + align:start position:0% +cancel that from the tape okay right + + + align:start position:0% +cancel that from the tape okay right +yeah so the second X derivative was just + + align:start position:0% +yeah so the second X derivative was just + + + align:start position:0% +yeah so the second X derivative was just +e the x e to the X cos y didn't move + + align:start position:0% +e the x e to the X cos y didn't move + + + align:start position:0% +e the x e to the X cos y didn't move +sorry that was frightening okay and then + + align:start position:0% +sorry that was frightening okay and then + + + align:start position:0% +sorry that was frightening okay and then +now here's the second second y + + align:start position:0% +now here's the second second y + + + align:start position:0% +now here's the second second y +derivative in other words it gives zero + + align:start position:0% +derivative in other words it gives zero + + + align:start position:0% +derivative in other words it gives zero +give zero and this one would too yeah so + + align:start position:0% +give zero and this one would too yeah so + + + align:start position:0% +give zero and this one would too yeah so +those are two now I will not do I don't + + align:start position:0% +those are two now I will not do I don't + + + align:start position:0% +those are two now I will not do I don't +really have an idea of what those what + + align:start position:0% +really have an idea of what those what + + + align:start position:0% +really have an idea of what those what +the picture is like + + align:start position:0% +the picture is like + + + align:start position:0% +the picture is like +uh but + + align:start position:0% +uh but + + + align:start position:0% +uh but +um + + align:start position:0% +um + + + align:start position:0% +um +it it's important we've got a flow field + + align:start position:0% +it it's important we've got a flow field + + + align:start position:0% +it it's important we've got a flow field +here and and it's from e to the z e to + + align:start position:0% +here and and it's from e to the z e to + + + align:start position:0% +here and and it's from e to the z e to +the X Plus i y exponential is a got to + + align:start position:0% +the X Plus i y exponential is a got to + + + align:start position:0% +the X Plus i y exponential is a got to +be an important function so it's got to + + align:start position:0% +be an important function so it's got to + + + align:start position:0% +be an important function so it's got to +be somehow interesting what do you think + + align:start position:0% +be somehow interesting what do you think + + + align:start position:0% +be somehow interesting what do you think +so what would the uh + + align:start position:0% +so what would the uh + + + align:start position:0% +so what would the uh +what would the ex equip potential lines + + align:start position:0% +what would the ex equip potential lines + + + align:start position:0% +what would the ex equip potential lines +look like oh boy e to X cos yal constant + + align:start position:0% +look like oh boy e to X cos yal constant + + + align:start position:0% +look like oh boy e to X cos yal constant +my gosh e to X cos y so let's see + + align:start position:0% +my gosh e to X cos y so let's see + + + align:start position:0% +my gosh e to X cos y so let's see +I I don't know how to draw this picture + + align:start position:0% +I I don't know how to draw this picture + + + align:start position:0% +I I don't know how to draw this picture +but I but one thing I know + + align:start position:0% +but I but one thing I know + + + align:start position:0% +but I but one thing I know +is that if I changed y by 2 pi I would + + align:start position:0% +is that if I changed y by 2 pi I would + + + align:start position:0% +is that if I changed y by 2 pi I would +get another copy of of this curve right + + align:start position:0% +get another copy of of this curve right + + + align:start position:0% +get another copy of of this curve right +if I changed y by every time you see + + align:start position:0% +if I changed y by every time you see + + + align:start position:0% +if I changed y by every time you see +cosine or S you think hey that's + + align:start position:0% +cosine or S you think hey that's + + + align:start position:0% +cosine or S you think hey that's +periodic if I change it by 2 pi so I'm + + align:start position:0% +periodic if I change it by 2 pi so I'm + + + align:start position:0% +periodic if I change it by 2 pi so I'm +thinking that the I'm thinking that say + + align:start position:0% +thinking that the I'm thinking that say + + + align:start position:0% +thinking that the I'm thinking that say +why from I I'm thinking that y between Z + + align:start position:0% +why from I I'm thinking that y between Z + + + align:start position:0% +why from I I'm thinking that y between Z +and 2 pi so here's yal 0 + + align:start position:0% +and 2 pi so here's yal 0 + + + align:start position:0% +and 2 pi so here's yal 0 +and yal 2 pi I'm thinking that my flow + + align:start position:0% +and yal 2 pi I'm thinking that my flow + + + align:start position:0% +and yal 2 pi I'm thinking that my flow +probably + + align:start position:0% +probably + + + align:start position:0% +probably +somehow is stays in a strip + + align:start position:0% +somehow is stays in a strip + + + align:start position:0% +somehow is stays in a strip +like that and then the whole thing just + + align:start position:0% +like that and then the whole thing just + + + align:start position:0% +like that and then the whole thing just +repeats and repeats and repeats so I I'm + + align:start position:0% +repeats and repeats and repeats so I I'm + + + align:start position:0% +repeats and repeats and repeats so I I'm +thinking really this is flow in an + + align:start position:0% +thinking really this is flow in an + + + align:start position:0% +thinking really this is flow in an +infinite strip infinite pipe or + + align:start position:0% +infinite strip infinite pipe or + + + align:start position:0% +infinite strip infinite pipe or +something like that you can imagine that + + align:start position:0% +something like that you can imagine that + + + align:start position:0% +something like that you can imagine that +that could be there could be + + align:start position:0% +that could be there could be + + + align:start position:0% +that could be there could be +applications so I but I still haven't + + align:start position:0% +applications so I but I still haven't + + + align:start position:0% +applications so I but I still haven't +drawn the curve I just think uh let's + + align:start position:0% +drawn the curve I just think uh let's + + + align:start position:0% +drawn the curve I just think uh let's +see what what would it look like when Y + + align:start position:0% +see what what would it look like when Y + + + align:start position:0% +see what what would it look like when Y +is a little + + align:start position:0% +is a little + + + align:start position:0% +is a little +suppose I'm trying to draw the picture + + align:start position:0% +suppose I'm trying to draw the picture + + + align:start position:0% +suppose I'm trying to draw the picture +of e to the X cos yal + + align:start position:0% +of e to the X cos yal + + + align:start position:0% +of e to the X cos yal +1 whatever okay + + align:start position:0% +1 whatever okay + + + align:start position:0% +1 whatever okay +let me try to I'll just attempt to draw + + align:start position:0% +let me try to I'll just attempt to draw + + + align:start position:0% +let me try to I'll just attempt to draw +that curve just just + + align:start position:0% +that curve just just + + + align:start position:0% +that curve just just +so if y was a little bit just a little + + align:start position:0% +so if y was a little bit just a little + + + align:start position:0% +so if y was a little bit just a little +bit off of zero the cosine would be + + align:start position:0% +bit off of zero the cosine would be + + + align:start position:0% +bit off of zero the cosine would be +yeah how's it going to go if Y is just a + + align:start position:0% +yeah how's it going to go if Y is just a + + + align:start position:0% +yeah how's it going to go if Y is just a +little off zero + + align:start position:0% +little off zero + + + align:start position:0% +little off zero +uh + + align:start position:0% + + + + align:start position:0% + +well can are tell me any points on this + + align:start position:0% +well can are tell me any points on this + + + align:start position:0% +well can are tell me any points on this +curve + + align:start position:0% +curve + + + align:start position:0% +curve +uh yeah + + align:start position:0% +uh yeah + + + align:start position:0% +uh yeah +I I can see that my yeah e to the x is + + align:start position:0% +I I can see that my yeah e to the x is + + + align:start position:0% +I I can see that my yeah e to the x is +going to be a big number if if x + + align:start position:0% +going to be a big number if if x + + + align:start position:0% +going to be a big number if if x +yeah is z z on the curve good got one + + align:start position:0% +yeah is z z on the curve good got one + + + align:start position:0% +yeah is z z on the curve good got one +point all right got got the easier now + + align:start position:0% +point all right got got the easier now + + + align:start position:0% +point all right got got the easier now +all right uh now suppose Y is a little + + align:start position:0% +all right uh now suppose Y is a little + + + align:start position:0% +all right uh now suppose Y is a little +bit more than zero so suppose I go up a + + align:start position:0% +bit more than zero so suppose I go up a + + + align:start position:0% +bit more than zero so suppose I go up a +little bit then what one Z or something + + align:start position:0% +little bit then what one Z or something + + + align:start position:0% +little bit then what one Z or something +yeah suppose + + align:start position:0% +yeah suppose + + + align:start position:0% +yeah suppose +one zero no no uh yeah so so if y goes + + align:start position:0% +one zero no no uh yeah so so if y goes + + + align:start position:0% +one zero no no uh yeah so so if y goes +up a little + + align:start position:0% +up a little + + + align:start position:0% +up a little +uh then X would go out a little bit I I + + align:start position:0% +uh then X would go out a little bit I I + + + align:start position:0% +uh then X would go out a little bit I I +think you think so what's happening so + + align:start position:0% +think you think so what's happening so + + + align:start position:0% +think you think so what's happening so +cosine of Y so what's the cosine of Y is + + align:start position:0% +cosine of Y so what's the cosine of Y is + + + align:start position:0% +cosine of Y so what's the cosine of Y is +the cosine of Y is going to drop from + + align:start position:0% +the cosine of Y is going to drop from + + + align:start position:0% +the cosine of Y is going to drop from +one to zero right + + align:start position:0% +one to zero right + + + align:start position:0% +one to zero right +to start with then if this cosine of Y + + align:start position:0% +to start with then if this cosine of Y + + + align:start position:0% +to start with then if this cosine of Y +is dropping from one to zero then this e + + align:start position:0% +is dropping from one to zero then this e + + + align:start position:0% +is dropping from one to zero then this e +to the X has got to climb up + + align:start position:0% +to the X has got to climb up + + + align:start position:0% +to the X has got to climb up +to to keep the product one so I'll move + + align:start position:0% +to to keep the product one so I'll move + + + align:start position:0% +to to keep the product one so I'll move +out so somehow it'll move out I I don't + + align:start position:0% +out so somehow it'll move out I I don't + + + align:start position:0% +out so somehow it'll move out I I don't +know what the + + align:start position:0% +know what the + + + align:start position:0% +know what the +this is at well yeah that's really at pi + + align:start position:0% +this is at well yeah that's really at pi + + + align:start position:0% +this is at well yeah that's really at pi +over two when + + align:start position:0% +over two when + + + align:start position:0% +over two when +maybe I think it's I think maybe at that + + align:start position:0% +maybe I think it's I think maybe at that + + + align:start position:0% +maybe I think it's I think maybe at that +point Pi when when y reaches Pi / 2 then + + align:start position:0% +point Pi when when y reaches Pi / 2 then + + + align:start position:0% +point Pi when when y reaches Pi / 2 then +the cosine has got down to zero + + align:start position:0% +the cosine has got down to zero + + + align:start position:0% +the cosine has got down to zero +you know + + align:start position:0% +you know + + + align:start position:0% +you know +we could we could work on this for a + + align:start position:0% +we could we could work on this for a + + + align:start position:0% +we could we could work on this for a +while or or we could let mat lab draw it + + align:start position:0% +while or or we could let mat lab draw it + + + align:start position:0% +while or or we could let mat lab draw it +but I think that we would see these uh + + align:start position:0% +but I think that we would see these uh + + + align:start position:0% +but I think that we would see these uh +and I I could do better I'm feeling + + align:start position:0% +and I I could do better I'm feeling + + + align:start position:0% +and I I could do better I'm feeling +pretty humiliated to not have a better + + align:start position:0% +pretty humiliated to not have a better + + + align:start position:0% +pretty humiliated to not have a better +picture here suppose Y is a little less + + align:start position:0% +picture here suppose Y is a little less + + + align:start position:0% +picture here suppose Y is a little less +than zero do we get anything interesting + + align:start position:0% +than zero do we get anything interesting + + + align:start position:0% +than zero do we get anything interesting +there oh well the cosine is an even + + align:start position:0% +there oh well the cosine is an even + + + align:start position:0% +there oh well the cosine is an even +function so I think the thing might is + + align:start position:0% +function so I think the thing might is + + + align:start position:0% +function so I think the thing might is +it just going to turn around like that + + align:start position:0% +it just going to turn around like that + + + align:start position:0% +it just going to turn around like that +I mean so that Y and minus y for this + + align:start position:0% +I mean so that Y and minus y for this + + + align:start position:0% +I mean so that Y and minus y for this +for a certain X the Y value and the + + align:start position:0% +for a certain X the Y value and the + + + align:start position:0% +for a certain X the Y value and the +minus y will both be on the curve + + align:start position:0% +minus y will both be on the curve + + + align:start position:0% +minus y will both be on the curve +because the cosine doesn't know whether + + align:start position:0% +because the cosine doesn't know whether + + + align:start position:0% +because the cosine doesn't know whether +it's the cosine of a plus or a minus + + align:start position:0% +it's the cosine of a plus or a minus + + + align:start position:0% +it's the cosine of a plus or a minus +yeah I I think we would get curves of + + align:start position:0% +yeah I I think we would get curves of + + + align:start position:0% +yeah I I think we would get curves of +that sort yeah yeah + + align:start position:0% +that sort yeah yeah + + + align:start position:0% +that sort yeah yeah +and then the uh the other the curves + + align:start position:0% +and then the uh the other the curves + + + align:start position:0% +and then the uh the other the curves +seal constant the streamlines will + + align:start position:0% +seal constant the streamlines will + + + align:start position:0% +seal constant the streamlines will +somehow go vertically yeah I maybe I'll + + align:start position:0% +somehow go vertically yeah I maybe I'll + + + align:start position:0% +somehow go vertically yeah I maybe I'll +just not use the whole time to + + align:start position:0% +just not use the whole time to + + + align:start position:0% +just not use the whole time to +to uh work on that particular curve I + + align:start position:0% +to uh work on that particular curve I + + + align:start position:0% +to uh work on that particular curve I +would have to prepare it but the point + + align:start position:0% +would have to prepare it but the point + + + align:start position:0% +would have to prepare it but the point +is you see how incredibly easily we + + align:start position:0% +is you see how incredibly easily we + + + align:start position:0% +is you see how incredibly easily we +produce solutions that lasses equation + + align:start position:0% +produce solutions that lasses equation + + + align:start position:0% +produce solutions that lasses equation +that you wouldn't have thought of and I + + align:start position:0% +that you wouldn't have thought of and I + + + align:start position:0% +that you wouldn't have thought of and I +wouldn't have thought of so that would + + align:start position:0% +wouldn't have thought of so that would + + + align:start position:0% +wouldn't have thought of so that would +be one way to produce Solutions I I'll I + + align:start position:0% +be one way to produce Solutions I I'll I + + + align:start position:0% +be one way to produce Solutions I I'll I +might even repeat this one in class uh + + align:start position:0% +might even repeat this one in class uh + + + align:start position:0% +might even repeat this one in class uh +Friday or I might not let me suggest + + align:start position:0% +Friday or I might not let me suggest + + + align:start position:0% +Friday or I might not let me suggest +another couple of possibilities that I + + align:start position:0% +another couple of possibilities that I + + + align:start position:0% +another couple of possibilities that I +will do in class uh can I just give you + + align:start position:0% +will do in class uh can I just give you + + + align:start position:0% +will do in class uh can I just give you +a couple of other functions F + + align:start position:0% +a couple of other functions F + + + align:start position:0% +a couple of other functions F +in fact I'll just erase that one and put + + align:start position:0% +in fact I'll just erase that one and put + + + align:start position:0% +in fact I'll just erase that one and put +in some other ones suppose I took the + + align:start position:0% +in some other ones suppose I took the + + + align:start position:0% +in some other ones suppose I took the +function + + align:start position:0% +function + + + align:start position:0% +function +1 over x + i y + + align:start position:0% + + + + align:start position:0% + +what's its so that's a function of this + + align:start position:0% +what's its so that's a function of this + + + align:start position:0% +what's its so that's a function of this +magic combination X Plus i y what's its + + align:start position:0% +magic combination X Plus i y what's its + + + align:start position:0% +magic combination X Plus i y what's its +real part and what's its imaginary part + + align:start position:0% +real part and what's its imaginary part + + + align:start position:0% +real part and what's its imaginary part +can you do you know how to split that + + align:start position:0% +can you do you know how to split that + + + align:start position:0% +can you do you know how to split that +guy into real and imaginary there a + + align:start position:0% +guy into real and imaginary there a + + + align:start position:0% +guy into real and imaginary there a +there's a little trick if you remember + + align:start position:0% +there's a little trick if you remember + + + align:start position:0% +there's a little trick if you remember +from learning complex numbers + + align:start position:0% +from learning complex numbers + + + align:start position:0% +from learning complex numbers +do you remember the trick the is that + + align:start position:0% +do you remember the trick the is that + + + align:start position:0% +do you remember the trick the is that +that this thing is down in the + + align:start position:0% +that this thing is down in the + + + align:start position:0% +that this thing is down in the +denominator right we don't want it there + + align:start position:0% +denominator right we don't want it there + + + align:start position:0% +denominator right we don't want it there +because we can't split the real + + align:start position:0% +because we can't split the real + + + align:start position:0% +because we can't split the real +imaginary Parts down there so I would + + align:start position:0% +imaginary Parts down there so I would + + + align:start position:0% +imaginary Parts down there so I would +like to rewrite it in a way that gets + + align:start position:0% +like to rewrite it in a way that gets + + + align:start position:0% +like to rewrite it in a way that gets +something real down the denominator + + align:start position:0% +something real down the denominator + + + align:start position:0% +something real down the denominator +moves all the i stuff up in the + + align:start position:0% +moves all the i stuff up in the + + + align:start position:0% +moves all the i stuff up in the +numerator where I can separate do how do + + align:start position:0% +numerator where I can separate do how do + + + align:start position:0% +numerator where I can separate do how do +I do it + + align:start position:0% +I do it + + + align:start position:0% +I do it +good multiply both sides by both top and + + align:start position:0% +good multiply both sides by both top and + + + align:start position:0% +good multiply both sides by both top and +bottom by + + align:start position:0% +bottom by + + + align:start position:0% +bottom by +by x minus iy good + + align:start position:0% +by x minus iy good + + + align:start position:0% +by x minus iy good +that that that trick puts so what does + + align:start position:0% +that that that trick puts so what does + + + align:start position:0% +that that that trick puts so what does +that put down here now that's a number + + align:start position:0% +that put down here now that's a number + + + align:start position:0% +that put down here now that's a number +times its conjugate and that's going to + + align:start position:0% +times its conjugate and that's going to + + + align:start position:0% +times its conjugate and that's going to +produce + + align:start position:0% +produce + + + align:start position:0% +produce +X2 + + align:start position:0% +X2 + + + align:start position:0% +X2 +minus or plus + + align:start position:0% +minus or plus + + + align:start position:0% +minus or plus +plus y^2 right the number times its + + align:start position:0% +plus y^2 right the number times its + + + align:start position:0% +plus y^2 right the number times its +conjugate is the length squared and now + + align:start position:0% +conjugate is the length squared and now + + + align:start position:0% +conjugate is the length squared and now +we just have x - i y and now it's + + align:start position:0% +we just have x - i y and now it's + + + align:start position:0% +we just have x - i y and now it's +obvious what the U is + + align:start position:0% +obvious what the U is + + + align:start position:0% +obvious what the U is +the real part this is real now so the U + + align:start position:0% +the real part this is real now so the U + + + align:start position:0% +the real part this is real now so the U +is just X over x^2 + y^2 and the and the + + align:start position:0% +is just X over x^2 + y^2 and the and the + + + align:start position:0% +is just X over x^2 + y^2 and the and the +S is the minus y over x^2 + y^2 + + align:start position:0% +S is the minus y over x^2 + y^2 + + + align:start position:0% +S is the minus y over x^2 + y^2 +that's a very interesting flow that's an + + align:start position:0% +that's a very interesting flow that's an + + + align:start position:0% +that's a very interesting flow that's an +interesting flow and and we could do its + + align:start position:0% +interesting flow and and we could do its + + + align:start position:0% +interesting flow and and we could do its +picture and so on in fact it would be a + + align:start position:0% +picture and so on in fact it would be a + + + align:start position:0% +picture and so on in fact it would be a +nicer picture than the one we stopped on + + align:start position:0% +nicer picture than the one we stopped on + + + align:start position:0% +nicer picture than the one we stopped on +uh + + align:start position:0% +uh + + + align:start position:0% +uh +what what you what should I notice about + + align:start position:0% +what what you what should I notice about + + + align:start position:0% +what what you what should I notice about +this flow it yeah of course the flow is + + align:start position:0% +this flow it yeah of course the flow is + + + align:start position:0% +this flow it yeah of course the flow is +automatically + + align:start position:0% +automatically + + + align:start position:0% +automatically +um IR rotational the curl is zero + + align:start position:0% +um IR rotational the curl is zero + + + align:start position:0% +um IR rotational the curl is zero +because there is a there is a potential + + align:start position:0% +because there is a there is a potential + + + align:start position:0% +because there is a there is a potential +the gradient of a potential the gradient + + align:start position:0% +the gradient of a potential the gradient + + + align:start position:0% +the gradient of a potential the gradient +of of a potential is going to be uh free + + align:start position:0% +of of a potential is going to be uh free + + + align:start position:0% +of of a potential is going to be uh free +of rotation and there will be + + align:start position:0% +of rotation and there will be + + + align:start position:0% +of rotation and there will be +streamlines all those good things there + + align:start position:0% +streamlines all those good things there + + + align:start position:0% +streamlines all those good things there +so what + + align:start position:0% +so what + + + align:start position:0% +so what +there's one bad point about the flow + + align:start position:0% +there's one bad point about the flow + + + align:start position:0% +there's one bad point about the flow +though + + align:start position:0% +though + + + align:start position:0% +though +which is where at Z 0 the whole thing + + align:start position:0% +which is where at Z 0 the whole thing + + + align:start position:0% +which is where at Z 0 the whole thing +falls apart right if at the origin This + + align:start position:0% +falls apart right if at the origin This + + + align:start position:0% +falls apart right if at the origin This +falls apart so this is a great flow + + align:start position:0% +falls apart so this is a great flow + + + align:start position:0% +falls apart so this is a great flow +except at the origin it's uh it's very + + align:start position:0% +except at the origin it's uh it's very + + + align:start position:0% +except at the origin it's uh it's very +problematic it's singular at the origin + + align:start position:0% +problematic it's singular at the origin + + + align:start position:0% +problematic it's singular at the origin +so yeah so if we drew the pictures we + + align:start position:0% +so yeah so if we drew the pictures we + + + align:start position:0% +so yeah so if we drew the pictures we +would see you know something strange + + align:start position:0% +would see you know something strange + + + align:start position:0% +would see you know something strange +this is is this is going to zero at the + + align:start position:0% +this is is this is going to zero at the + + + align:start position:0% +this is is this is going to zero at the +origin so yeah we have trouble at the + + align:start position:0% +origin so yeah we have trouble at the + + + align:start position:0% +origin so yeah we have trouble at the +origin but an important flow otherwise + + align:start position:0% +origin but an important flow otherwise + + + align:start position:0% +origin but an important flow otherwise +yeah and I'll just mention the third but + + align:start position:0% +yeah and I'll just mention the third but + + + align:start position:0% +yeah and I'll just mention the third but +I won't do anything with it because I + + align:start position:0% +I won't do anything with it because I + + + align:start position:0% +I won't do anything with it because I +because it's such a neat one that I have + + align:start position:0% +because it's such a neat one that I have + + + align:start position:0% +because it's such a neat one that I have +to save it for uh Friday it's the other + + align:start position:0% +to save it for uh Friday it's the other + + + align:start position:0% +to save it for uh Friday it's the other +natural function to think of is the + + align:start position:0% +natural function to think of is the + + + align:start position:0% +natural function to think of is the +logarithm the logarithm of X+ iy + + align:start position:0% +logarithm the logarithm of X+ iy + + + align:start position:0% +logarithm the logarithm of X+ iy +split that into U and a yes + + align:start position:0% +split that into U and a yes + + + align:start position:0% +split that into U and a yes +what kind of thing do we have here what + + align:start position:0% +what kind of thing do we have here what + + + align:start position:0% +what kind of thing do we have here what +kind of Singularity I mean yeah let me + + align:start position:0% +kind of Singularity I mean yeah let me + + + align:start position:0% +kind of Singularity I mean yeah let me +just do two moments on this example and + + align:start position:0% +just do two moments on this example and + + + align:start position:0% +just do two moments on this example and +then leave it for Friday because it's + + align:start position:0% +then leave it for Friday because it's + + + align:start position:0% +then leave it for Friday because it's +the whole class has to see it uh is + + align:start position:0% +the whole class has to see it uh is + + + align:start position:0% +the whole class has to see it uh is +there a singularity for this guy + + align:start position:0% +there a singularity for this guy + + + align:start position:0% +there a singularity for this guy +is there a point XY where the logorithm + + align:start position:0% +is there a point XY where the logorithm + + + align:start position:0% +is there a point XY where the logorithm +is not uh great + + align:start position:0% +is not uh great + + + align:start position:0% +is not uh great +at the the origin again the or this will + + align:start position:0% +at the the origin again the or this will + + + align:start position:0% +at the the origin again the or this will +again have a singularity at the origin + + align:start position:0% +again have a singularity at the origin + + + align:start position:0% +again have a singularity at the origin +something strange is happening at the + + align:start position:0% +something strange is happening at the + + + align:start position:0% +something strange is happening at the +origin and and what we'll find is + + align:start position:0% +origin and and what we'll find is + + + align:start position:0% +origin and and what we'll find is +there's a Delta function there the we're + + align:start position:0% +there's a Delta function there the we're + + + align:start position:0% +there's a Delta function there the we're +feeding in uh we we have a source right + + align:start position:0% +feeding in uh we we have a source right + + + align:start position:0% +feeding in uh we we have a source right +at the origin and then it's flowing out + + align:start position:0% +at the origin and then it's flowing out + + + align:start position:0% +at the origin and then it's flowing out +uh on uh I think on radial lines I think + + align:start position:0% +uh on uh I think on radial lines I think + + + align:start position:0% +uh on uh I think on radial lines I think +the streamlines go out from the origin + + align:start position:0% +the streamlines go out from the origin + + + align:start position:0% +the streamlines go out from the origin +and the equip potentials go around the + + align:start position:0% +and the equip potentials go around the + + + align:start position:0% +and the equip potentials go around the +origin yeah it's a great example so + + align:start position:0% +origin yeah it's a great example so + + + align:start position:0% +origin yeah it's a great example so +that's another another one to come okay + + align:start position:0% +that's another another one to come okay + + + align:start position:0% +that's another another one to come okay +so examples like these are + + align:start position:0% +so examples like these are + + + align:start position:0% +so examples like these are +I mean + + align:start position:0% +I mean + + + align:start position:0% +I mean +generations of thinking went into uh + + align:start position:0% +generations of thinking went into uh + + + align:start position:0% +generations of thinking went into uh +Solutions of Thea equation yeah and in + + align:start position:0% +Solutions of Thea equation yeah and in + + + align:start position:0% +Solutions of Thea equation yeah and in +and 2D particularly where we have this + + align:start position:0% +and 2D particularly where we have this + + + align:start position:0% +and 2D particularly where we have this +special uh combination I'm I wish we had + + align:start position:0% +special uh combination I'm I wish we had + + + align:start position:0% +special uh combination I'm I wish we had +such a combination in 3D but we simply + + align:start position:0% +such a combination in 3D but we simply + + + align:start position:0% +such a combination in 3D but we simply +don't you know we can discuss the + + align:start position:0% +don't you know we can discuss the + + + align:start position:0% +don't you know we can discuss the +equation in 3D of course very important + + align:start position:0% +equation in 3D of course very important + + + align:start position:0% +equation in 3D of course very important +but I mean wave equation this the fact + + align:start position:0% +but I mean wave equation this the fact + + + align:start position:0% +but I mean wave equation this the fact +we're talking to each other is is uh got + + align:start position:0% +we're talking to each other is is uh got + + + align:start position:0% +we're talking to each other is is uh got +the lassan in 3D but + + align:start position:0% +the lassan in 3D but + + + align:start position:0% +the lassan in 3D but +it uh that there's no exp plus iy magic + + align:start position:0% +it uh that there's no exp plus iy magic + + + align:start position:0% +it uh that there's no exp plus iy magic +right okay that's some U's and S's and + + align:start position:0% +right okay that's some U's and S's and + + + align:start position:0% +right okay that's some U's and S's and +and v's and W's what else is on your + + align:start position:0% +and v's and W's what else is on your + + + align:start position:0% +and v's and W's what else is on your +mind + + align:start position:0% +mind + + + align:start position:0% +mind +question + + align:start position:0% +question + + + align:start position:0% +question +shall I + + align:start position:0% + + + + align:start position:0% + +I could ask this question oh here's + + align:start position:0% +I could ask this question oh here's + + + align:start position:0% +I could ask this question oh here's +something I did not do in class + + align:start position:0% + + + + align:start position:0% + +I I think I wrote down the Divergence + + align:start position:0% +I I think I wrote down the Divergence + + + align:start position:0% +I I think I wrote down the Divergence +Theorem so can we start by doing that + + align:start position:0% +Theorem so can we start by doing that + + + align:start position:0% +Theorem so can we start by doing that +let me write down the Divergence Theorem + + align:start position:0% +let me write down the Divergence Theorem + + + align:start position:0% +let me write down the Divergence Theorem +or let with your help + + align:start position:0% +or let with your help + + + align:start position:0% +or let with your help +and then uh use it + + align:start position:0% + + + + align:start position:0% + +so what does the Divergence theorem + + align:start position:0% +so what does the Divergence theorem + + + align:start position:0% +so what does the Divergence theorem +we're in 2D so this is 2D + + align:start position:0% +we're in 2D so this is 2D + + + align:start position:0% +we're in 2D so this is 2D +just a similar theorem and so what's the + + align:start position:0% +just a similar theorem and so what's the + + + align:start position:0% +just a similar theorem and so what's the +what is the theorem say + + align:start position:0% +what is the theorem say + + + align:start position:0% +what is the theorem say +that if I take the Divergence of some W + + align:start position:0% +that if I take the Divergence of some W + + + align:start position:0% +that if I take the Divergence of some W +some Vector field + + align:start position:0% +some Vector field + + + align:start position:0% +some Vector field +then and if I integrate that + + align:start position:0% +then and if I integrate that + + + align:start position:0% +then and if I integrate that +over some region so I have some region + + align:start position:0% +over some region so I have some region + + + align:start position:0% +over some region so I have some region +here and at every Point there's a flow + + align:start position:0% +here and at every Point there's a flow + + + align:start position:0% +here and at every Point there's a flow +W and I look at the Divergence of w and + + align:start position:0% +W and I look at the Divergence of w and + + + align:start position:0% +W and I look at the Divergence of w and +I integrate that dxdy + + align:start position:0% +I integrate that dxdy + + + align:start position:0% +I integrate that dxdy +so that's inte it's a double integral + + align:start position:0% +so that's inte it's a double integral + + + align:start position:0% +so that's inte it's a double integral +over a region + + align:start position:0% +over a region + + + align:start position:0% +over a region +I will get what what's the what is + + align:start position:0% +I will get what what's the what is + + + align:start position:0% +I will get what what's the what is +what's the right hand side + + align:start position:0% +what's the right hand side + + + align:start position:0% +what's the right hand side +what what is the Divergence measure + + align:start position:0% +what what is the Divergence measure + + + align:start position:0% +what what is the Divergence measure +so I'm really asking you like just + + align:start position:0% +so I'm really asking you like just + + + align:start position:0% +so I'm really asking you like just +memory what's the what is the Divergence + + align:start position:0% +memory what's the what is the Divergence + + + align:start position:0% +memory what's the what is the Divergence +what's it's an identity it's it's + + align:start position:0% +what's it's an identity it's it's + + + align:start position:0% +what's it's an identity it's it's +integration by Parts in some way as as + + align:start position:0% +integration by Parts in some way as as + + + align:start position:0% +integration by Parts in some way as as +we'll see uh but what do you remember + + align:start position:0% +we'll see uh but what do you remember + + + align:start position:0% +we'll see uh but what do you remember +for the Divergence Theorem + + align:start position:0% +for the Divergence Theorem + + + align:start position:0% +for the Divergence Theorem +you get what you get it measures how + + align:start position:0% +you get what you get it measures how + + + align:start position:0% +you get what you get it measures how +much + + align:start position:0% +much + + + align:start position:0% +much +flux out right so when we measure the + + align:start position:0% +flux out right so when we measure the + + + align:start position:0% +flux out right so when we measure the +flux out by integrating around the + + align:start position:0% +flux out by integrating around the + + + align:start position:0% +flux out by integrating around the +boundary how much is getting through the + + align:start position:0% +boundary how much is getting through the + + + align:start position:0% +boundary how much is getting through the +boundary and what's the flow through the + + align:start position:0% +boundary and what's the flow through the + + + align:start position:0% +boundary and what's the flow through the +boundary + + align:start position:0% +boundary + + + align:start position:0% +boundary +I take w but that's a vector and I'm + + align:start position:0% +I take w but that's a vector and I'm + + + align:start position:0% +I take w but that's a vector and I'm +looking for what component of w + + align:start position:0% +looking for what component of w + + + align:start position:0% +looking for what component of w +the normal component the component of w + + align:start position:0% +the normal component the component of w + + + align:start position:0% +the normal component the component of w +w.n the component of w that's headed out + + align:start position:0% +w.n the component of w that's headed out + + + align:start position:0% +w.n the component of w that's headed out +N is a is defined to be where whatever + + align:start position:0% +N is a is defined to be where whatever + + + align:start position:0% +N is a is defined to be where whatever +the boundary is here I made it look like + + align:start position:0% +the boundary is here I made it look like + + + align:start position:0% +the boundary is here I made it look like +a circle but I didn't shouldn't have let + + align:start position:0% +a circle but I didn't shouldn't have let + + + align:start position:0% +a circle but I didn't shouldn't have let +me let me make it a little wobbler or + + align:start position:0% +me let me make it a little wobbler or + + + align:start position:0% +me let me make it a little wobbler or +something uh yeah so the B the the + + align:start position:0% +something uh yeah so the B the the + + + align:start position:0% +something uh yeah so the B the the +normal component at any there look at + + align:start position:0% +normal component at any there look at + + + align:start position:0% +normal component at any there look at +that point + + align:start position:0% +that point + + + align:start position:0% +that point +the normal Direction Through The + + align:start position:0% +the normal Direction Through The + + + align:start position:0% +the normal Direction Through The +Boundary down in that crazy point is + + align:start position:0% +Boundary down in that crazy point is + + + align:start position:0% +Boundary down in that crazy point is +this way yeah so this the normal is + + align:start position:0% +this way yeah so this the normal is + + + align:start position:0% +this way yeah so this the normal is +going this way here here it's going over + + align:start position:0% +going this way here here it's going over + + + align:start position:0% +going this way here here it's going over +this way it's perpendicular to the + + align:start position:0% +this way it's perpendicular to the + + + align:start position:0% +this way it's perpendicular to the +boundary okay and then we integrate + + align:start position:0% +boundary okay and then we integrate + + + align:start position:0% +boundary okay and then we integrate +around the boundary all right + + align:start position:0% +around the boundary all right + + + align:start position:0% +around the boundary all right +yeah yeah so that's the identity of that + + align:start position:0% +yeah yeah so that's the identity of that + + + align:start position:0% +yeah yeah so that's the identity of that +that's the Divergence Theorem right + + align:start position:0% +that's the Divergence Theorem right + + + align:start position:0% +that's the Divergence Theorem right +now let's see + + align:start position:0% + + + + align:start position:0% + +could you yeah so here here's a we have + + align:start position:0% +could you yeah so here here's a we have + + + align:start position:0% +could you yeah so here here's a we have +a minute shall I do you want to give me + + align:start position:0% +a minute shall I do you want to give me + + + align:start position:0% +a minute shall I do you want to give me +a particular take a particular W and see + + align:start position:0% +a particular take a particular W and see + + + align:start position:0% +a particular take a particular W and see +if this would be correct + + align:start position:0% +if this would be correct + + + align:start position:0% +if this would be correct +huh how about W equal 0x our first + + align:start position:0% +huh how about W equal 0x our first + + + align:start position:0% +huh how about W equal 0x our first +example + + align:start position:0% +example + + + align:start position:0% +example +suppose I tried wals ZX I I just want to + + align:start position:0% +suppose I tried wals ZX I I just want to + + + align:start position:0% +suppose I tried wals ZX I I just want to +see if the Divergence + + align:start position:0% +see if the Divergence + + + align:start position:0% +see if the Divergence +what the flux is through the boundary + + align:start position:0% +what the flux is through the boundary + + + align:start position:0% +what the flux is through the boundary +what what region shall I take for the + + align:start position:0% +what what region shall I take for the + + + align:start position:0% +what what region shall I take for the +so so the Divergence Theorem has two + + align:start position:0% +so so the Divergence Theorem has two + + + align:start position:0% +so so the Divergence Theorem has two +inputs it has a flow field and let me + + align:start position:0% +inputs it has a flow field and let me + + + align:start position:0% +inputs it has a flow field and let me +take W to be 0x as just so it's a shear + + align:start position:0% +take W to be 0x as just so it's a shear + + + align:start position:0% +take W to be 0x as just so it's a shear +and a region + + align:start position:0% +and a region + + + align:start position:0% +and a region +and of course the integral might not be + + align:start position:0% +and of course the integral might not be + + + align:start position:0% +and of course the integral might not be +that much fun to do unless we make the + + align:start position:0% +that much fun to do unless we make the + + + align:start position:0% +that much fun to do unless we make the +region nice what do you take as a nice + + align:start position:0% +region nice what do you take as a nice + + + align:start position:0% +region nice what do you take as a nice +region for uh + + align:start position:0% +region for uh + + + align:start position:0% +region for uh +oh + + align:start position:0% +oh + + + align:start position:0% +oh +actually it doesn't matter what the + + align:start position:0% +actually it doesn't matter what the + + + align:start position:0% +actually it doesn't matter what the +region is take any old region for the + + align:start position:0% +region is take any old region for the + + + align:start position:0% +region is take any old region for the +moment + + align:start position:0% +moment + + + align:start position:0% +moment +what's the answer for for this + + align:start position:0% +what's the answer for for this + + + align:start position:0% +what's the answer for for this +particular flow W equals 0x + + align:start position:0% + + + + align:start position:0% + +zero + + align:start position:0% +zero + + + align:start position:0% +zero +that's the right that's the cool part if + + align:start position:0% +that's the right that's the cool part if + + + align:start position:0% +that's the right that's the cool part if +they answer zero then like you know work + + align:start position:0% +they answer zero then like you know work + + + align:start position:0% +they answer zero then like you know work +is suspended + + align:start position:0% +is suspended + + + align:start position:0% +is suspended +and why is it zero + + align:start position:0% +and why is it zero + + + align:start position:0% +and why is it zero +because the Divergence of this + + align:start position:0% +because the Divergence of this + + + align:start position:0% +because the Divergence of this +particular W the X derivative of that + + align:start position:0% +particular W the X derivative of that + + + align:start position:0% +particular W the X derivative of that +plus the Y derivative of that is zero + + align:start position:0% +plus the Y derivative of that is zero + + + align:start position:0% +plus the Y derivative of that is zero +this has Divergence Z everywhere zero + + align:start position:0% +this has Divergence Z everywhere zero + + + align:start position:0% +this has Divergence Z everywhere zero +so integrating is no problem at all so + + align:start position:0% +so integrating is no problem at all so + + + align:start position:0% +so integrating is no problem at all so +the so that would be zero for this flow + + align:start position:0% +the so that would be zero for this flow + + + align:start position:0% +the so that would be zero for this flow +field for for this Divergence free field + + align:start position:0% +field for for this Divergence free field + + + align:start position:0% +field for for this Divergence free field +zero for that because + + align:start position:0% +zero for that because + + + align:start position:0% +zero for that because +div W is zero + + align:start position:0% + + + + align:start position:0% + +but is that correct what does that tell + + align:start position:0% +but is that correct what does that tell + + + align:start position:0% +but is that correct what does that tell +me this these flows are we saw what the + + align:start position:0% +me this these flows are we saw what the + + + align:start position:0% +me this these flows are we saw what the +flow was like here's say there's the + + align:start position:0% +flow was like here's say there's the + + + align:start position:0% +flow was like here's say there's the +origin it doesn't have to be a circle it + + align:start position:0% +origin it doesn't have to be a circle it + + + align:start position:0% +origin it doesn't have to be a circle it +looks like a circle + + align:start position:0% +looks like a circle + + + align:start position:0% +looks like a circle +do you see why the flux is zero there is + + align:start position:0% +do you see why the flux is zero there is + + + align:start position:0% +do you see why the flux is zero there is +there is flow through the boundary right + + align:start position:0% +there is flow through the boundary right + + + align:start position:0% +there is flow through the boundary right +flow is going buzz buzz buzz up this + + align:start position:0% +flow is going buzz buzz buzz up this + + + align:start position:0% +flow is going buzz buzz buzz up this +line and out + + align:start position:0% +line and out + + + align:start position:0% +line and out +and and it's coming in here so the right + + align:start position:0% +and and it's coming in here so the right + + + align:start position:0% +and and it's coming in here so the right +that that's what we discovered the this + + align:start position:0% +that that's what we discovered the this + + + align:start position:0% +that that's what we discovered the this +ZX is vertical flow + + align:start position:0% + + + + align:start position:0% + +it hasn't got any horizontal component + + align:start position:0% +it hasn't got any horizontal component + + + align:start position:0% +it hasn't got any horizontal component +it's vertical it's got a vertical + + align:start position:0% +it's vertical it's got a vertical + + + align:start position:0% +it's vertical it's got a vertical +component it's going out and would we + + align:start position:0% +component it's going out and would we + + + align:start position:0% +component it's going out and would we +want to do this right hand side I don't + + align:start position:0% +want to do this right hand side I don't + + + align:start position:0% +want to do this right hand side I don't +think so right this right hand side is + + align:start position:0% +think so right this right hand side is + + + align:start position:0% +think so right this right hand side is +asking me what I have to find the normal + + align:start position:0% +asking me what I have to find the normal + + + align:start position:0% +asking me what I have to find the normal +Direction on this whatever curve that is + + align:start position:0% +Direction on this whatever curve that is + + + align:start position:0% +Direction on this whatever curve that is +I have to take its dotproduct with the + + align:start position:0% +I have to take its dotproduct with the + + + align:start position:0% +I have to take its dotproduct with the +flow 0x so this is the this is uh some + + align:start position:0% +flow 0x so this is the this is uh some + + + align:start position:0% +flow 0x so this is the this is uh some +quantity and then I have to do this DS + + align:start position:0% +quantity and then I have to do this DS + + + align:start position:0% +quantity and then I have to do this DS +which I haven't even mentioned DS is Arc + + align:start position:0% +which I haven't even mentioned DS is Arc + + + align:start position:0% +which I haven't even mentioned DS is Arc +Length around I'm integrating around + + align:start position:0% +Length around I'm integrating around + + + align:start position:0% +Length around I'm integrating around +these pieces but but yet + + align:start position:0% +these pieces but but yet + + + align:start position:0% +these pieces but but yet +somehow we have some idea that the from + + align:start position:0% +somehow we have some idea that the from + + + align:start position:0% +somehow we have some idea that the from +that picture that the total flux is zero + + align:start position:0% +that picture that the total flux is zero + + + align:start position:0% +that picture that the total flux is zero +what how would you say it in words if I + + align:start position:0% +what how would you say it in words if I + + + align:start position:0% +what how would you say it in words if I +say here's the flow field there's a + + align:start position:0% +say here's the flow field there's a + + + align:start position:0% +say here's the flow field there's a +region funny shape + + align:start position:0% +region funny shape + + + align:start position:0% +region funny shape +the flux is zero through that boundary + + align:start position:0% +the flux is zero through that boundary + + + align:start position:0% +the flux is zero through that boundary +and and if I asked you why what would + + align:start position:0% +and and if I asked you why what would + + + align:start position:0% +and and if I asked you why what would +you say you I mean a math answer would + + align:start position:0% +you say you I mean a math answer would + + + align:start position:0% +you say you I mean a math answer would +be use the Divergence Theorem but okay + + align:start position:0% +be use the Divergence Theorem but okay + + + align:start position:0% +be use the Divergence Theorem but okay +but why from this picture does it look + + align:start position:0% +but why from this picture does it look + + + align:start position:0% +but why from this picture does it look +like we have zero flux + + align:start position:0% +like we have zero flux + + + align:start position:0% +like we have zero flux +what comes in goes out yeah what's + + align:start position:0% +what comes in goes out yeah what's + + + align:start position:0% +what comes in goes out yeah what's +coming in the bottom here is going out + + align:start position:0% +coming in the bottom here is going out + + + align:start position:0% +coming in the bottom here is going out +the top yeah yeah that's that's + + align:start position:0% +the top yeah yeah that's that's + + + align:start position:0% +the top yeah yeah that's that's +basically it right right yeah yeah so we + + align:start position:0% +basically it right right yeah yeah so we + + + align:start position:0% +basically it right right yeah yeah so we +would get zero for that one so I'm + + align:start position:0% +would get zero for that one so I'm + + + align:start position:0% +would get zero for that one so I'm +you if if if I think the homework the + + align:start position:0% +you if if if I think the homework the + + + align:start position:0% +you if if if I think the homework the +suggested homework maybe includes an + + align:start position:0% +suggested homework maybe includes an + + + align:start position:0% +suggested homework maybe includes an +example where the Divergence isn't zero + + align:start position:0% +example where the Divergence isn't zero + + + align:start position:0% +example where the Divergence isn't zero +and then you actually have to do these + + align:start position:0% +and then you actually have to do these + + + align:start position:0% +and then you actually have to do these +integrals just as like practice for what + + align:start position:0% +integrals just as like practice for what + + + align:start position:0% +integrals just as like practice for what +do those integrals mean yeah maybe I + + align:start position:0% +do those integrals mean yeah maybe I + + + align:start position:0% +do those integrals mean yeah maybe I +won't go through one now but that's good + + align:start position:0% +won't go through one now but that's good + + + align:start position:0% +won't go through one now but that's good +practice is take a some simple W but one + + align:start position:0% +practice is take a some simple W but one + + + align:start position:0% +practice is take a some simple W but one +with + + align:start position:0% +with + + + align:start position:0% +with +with with with a nonzero Divergence and + + align:start position:0% +with with with a nonzero Divergence and + + + align:start position:0% +with with with a nonzero Divergence and +then see if you can do either or both of + + align:start position:0% +then see if you can do either or both of + + + align:start position:0% +then see if you can do either or both of +the integrals that are supposed to come + + align:start position:0% +the integrals that are supposed to come + + + align:start position:0% +the integrals that are supposed to come +out equal yeah yeah that's a that's a + + align:start position:0% +out equal yeah yeah that's a that's a + + + align:start position:0% +out equal yeah yeah that's a that's a +good one + + align:start position:0% +good one + + + align:start position:0% +good one +now there's one thing I could any + + align:start position:0% +now there's one thing I could any + + + align:start position:0% +now there's one thing I could any +question or discussion yeah it's you + + align:start position:0% +question or discussion yeah it's you + + + align:start position:0% +question or discussion yeah it's you +guys are seeing these uh + + align:start position:0% +guys are seeing these uh + + + align:start position:0% +guys are seeing these uh +examples come up it's the only way I + + align:start position:0% +examples come up it's the only way I + + + align:start position:0% +examples come up it's the only way I +would know to learn this subject is take + + align:start position:0% +would know to learn this subject is take + + + align:start position:0% +would know to learn this subject is take +simple v's and ws and uh um see what you + + align:start position:0% +simple v's and ws and uh um see what you + + + align:start position:0% +simple v's and ws and uh um see what you +can do with them + + align:start position:0% +can do with them + + + align:start position:0% +can do with them +uh we've got the general principles but + + align:start position:0% +uh we've got the general principles but + + + align:start position:0% +uh we've got the general principles but +then apply them to specific flows + + align:start position:0% +then apply them to specific flows + + + align:start position:0% +then apply them to specific flows +um + + align:start position:0% +um + + + align:start position:0% +um +yes thanks that app for + + align:start position:0% +yes thanks that app for + + + align:start position:0% +yes thanks that app for +nonre + + align:start position:0% + + + + align:start position:0% + +uh this theorem + + align:start position:0% +uh this theorem + + + align:start position:0% +uh this theorem +right the flow in flow out but if it was + + align:start position:0% +right the flow in flow out but if it was + + + align:start position:0% +right the flow in flow out but if it was +like + + align:start position:0% +like + + + align:start position:0% +like +yeah if it was well let's draw a funny + + align:start position:0% +yeah if it was well let's draw a funny + + + align:start position:0% +yeah if it was well let's draw a funny +shape + + align:start position:0% +shape + + + align:start position:0% +shape +see what we think I mean let's with this + + align:start position:0% +see what we think I mean let's with this + + + align:start position:0% +see what we think I mean let's with this +flow right uh I mean if the + + align:start position:0% +flow right uh I mean if the + + + align:start position:0% +flow right uh I mean if the +if let me just say if the flow is not if + + align:start position:0% +if let me just say if the flow is not if + + + align:start position:0% +if let me just say if the flow is not if +it has some difficult Divergence and the + + align:start position:0% +it has some difficult Divergence and the + + + align:start position:0% +it has some difficult Divergence and the +and the region is some mess nobody's + + align:start position:0% +and the region is some mess nobody's + + + align:start position:0% +and the region is some mess nobody's +going to be able to do it right I mean + + align:start position:0% +going to be able to do it right I mean + + + align:start position:0% +going to be able to do it right I mean +yeah so don't think that these can all + + align:start position:0% +yeah so don't think that these can all + + + align:start position:0% +yeah so don't think that these can all +be done the the equ quality is it's like + + align:start position:0% +be done the the equ quality is it's like + + + align:start position:0% +be done the the equ quality is it's like +integrals in calculus + + align:start position:0% +integrals in calculus + + + align:start position:0% +integrals in calculus +no problem to think of Integrations that + + align:start position:0% +no problem to think of Integrations that + + + align:start position:0% +no problem to think of Integrations that +are just beyond human capacity but the + + align:start position:0% +are just beyond human capacity but the + + + align:start position:0% +are just beyond human capacity but the +formulas still hold suppose my region + + align:start position:0% +formulas still hold suppose my region + + + align:start position:0% +formulas still hold suppose my region +was even like this + + align:start position:0% + + + + align:start position:0% + +would that still be would it do we still + + align:start position:0% +would that still be would it do we still + + + align:start position:0% +would that still be would it do we still +see flow in equals flow out for this + + align:start position:0% +see flow in equals flow out for this + + + align:start position:0% +see flow in equals flow out for this +particular flow I I think yeah the flow + + align:start position:0% +particular flow I I think yeah the flow + + + align:start position:0% +particular flow I I think yeah the flow +is going this way so it's coming in here + + align:start position:0% +is going this way so it's coming in here + + + align:start position:0% +is going this way so it's coming in here +it's going out out again that + + align:start position:0% +it's going out out again that + + + align:start position:0% +it's going out out again that +contributes back in again here and out + + align:start position:0% +contributes back in again here and out + + + align:start position:0% +contributes back in again here and out +again here yeah I think uh I think our + + align:start position:0% +again here yeah I think uh I think our + + + align:start position:0% +again here yeah I think uh I think our +our uh Instinct would be correct there + + align:start position:0% +our uh Instinct would be correct there + + + align:start position:0% +our uh Instinct would be correct there +yeah yeah yeah all all sorts of examples + + align:start position:0% +yeah yeah yeah all all sorts of examples + + + align:start position:0% +yeah yeah yeah all all sorts of examples +I I was going to well I'll maybe do it + + align:start position:0% +I I was going to well I'll maybe do it + + + align:start position:0% +I I was going to well I'll maybe do it +in class um yeah this this Divergent + + align:start position:0% +in class um yeah this this Divergent + + + align:start position:0% +in class um yeah this this Divergent +theem is is like it's the fundamental + + align:start position:0% +theem is is like it's the fundamental + + + align:start position:0% +theem is is like it's the fundamental +theorem of 2D calculus you could say or + + align:start position:0% +theorem of 2D calculus you could say or + + + align:start position:0% +theorem of 2D calculus you could say or +one of them and uh um + + align:start position:0% +one of them and uh um + + + align:start position:0% +one of them and uh um +yeah and and to see what these uh + + align:start position:0% +yeah and and to see what these uh + + + align:start position:0% +yeah and and to see what these uh +yeah to to to write these things and and + + align:start position:0% +yeah to to to write these things and and + + + align:start position:0% +yeah to to to write these things and and +and and see what they what they lead to + + align:start position:0% +and and see what they what they lead to + + + align:start position:0% +and and see what they what they lead to +yeah may maybe I'll I won't what I'll + + align:start position:0% +yeah may maybe I'll I won't what I'll + + + align:start position:0% +yeah may maybe I'll I won't what I'll +tell you what I was going to do I was + + align:start position:0% +tell you what I was going to do I was + + + align:start position:0% +tell you what I was going to do I was +going to apply this to the to a vector + + align:start position:0% +going to apply this to the to a vector + + + align:start position:0% +going to apply this to the to a vector +field U * W so U is a scaler W is a + + align:start position:0% +field U * W so U is a scaler W is a + + + align:start position:0% +field U * W so U is a scaler W is a +vector and and and therefore UW is a + + align:start position:0% +vector and and and therefore UW is a + + + align:start position:0% +vector and and and therefore UW is a +vector it's got two components uw1 and + + align:start position:0% +vector it's got two components uw1 and + + + align:start position:0% +vector it's got two components uw1 and +so sh are you willing to do that one + + align:start position:0% +so sh are you willing to do that one + + + align:start position:0% +so sh are you willing to do that one +so I apply it to apply it to apply this + + align:start position:0% +so I apply it to apply it to apply this + + + align:start position:0% +so I apply it to apply it to apply this +to not to W itself but to U * W which is + + align:start position:0% +to not to W itself but to U * W which is + + + align:start position:0% +to not to W itself but to U * W which is +has two components U W1 and uw2 + + align:start position:0% +has two components U W1 and uw2 + + + align:start position:0% +has two components U W1 and uw2 +okay so I should take the Divergence of + + align:start position:0% +okay so I should take the Divergence of + + + align:start position:0% +okay so I should take the Divergence of +UW + + align:start position:0% +UW + + + align:start position:0% +UW +I mean that's that's a vector field UW + + align:start position:0% +I mean that's that's a vector field UW + + + align:start position:0% +I mean that's that's a vector field UW +this guy and I'll get the U.N + + align:start position:0% +this guy and I'll get the U.N + + + align:start position:0% +this guy and I'll get the U.N +and it just turns out that this is the + + align:start position:0% +and it just turns out that this is the + + + align:start position:0% +and it just turns out that this is the +right way to do it + + align:start position:0% +right way to do it + + + align:start position:0% +right way to do it +um to see the fact that gradient and + + align:start position:0% +um to see the fact that gradient and + + + align:start position:0% +um to see the fact that gradient and +Divergence are transposes of each other + + align:start position:0% +Divergence are transposes of each other + + + align:start position:0% +Divergence are transposes of each other +yeah yeah maybe I won't do that + + align:start position:0% +yeah yeah maybe I won't do that + + + align:start position:0% +yeah yeah maybe I won't do that +calculation now I'll just say that if if + + align:start position:0% +calculation now I'll just say that if if + + + align:start position:0% +calculation now I'll just say that if if +you take the Divergence Theorem and you + + align:start position:0% +you take the Divergence Theorem and you + + + align:start position:0% +you take the Divergence Theorem and you +apply it to this guy uw1 uw2 + + align:start position:0% +apply it to this guy uw1 uw2 + + + align:start position:0% +apply it to this guy uw1 uw2 +then you and write out what it means you + + align:start position:0% +then you and write out what it means you + + + align:start position:0% +then you and write out what it means you +you get a very in interesting formula + + align:start position:0% +you get a very in interesting formula + + + align:start position:0% +you get a very in interesting formula +yeah yeah yeah that's + + align:start position:0% +yeah yeah yeah that's + + + align:start position:0% +yeah yeah yeah that's +I I'll just leave that there so I'm + + align:start position:0% +I I'll just leave that there so I'm + + + align:start position:0% +I I'll just leave that there so I'm +ready for a final question if there is + + align:start position:0% +ready for a final question if there is + + + align:start position:0% +ready for a final question if there is +one or otherwise keep going Friday with + + align:start position:0% +one or otherwise keep going Friday with + + + align:start position:0% +one or otherwise keep going Friday with +the uh with these laass equation + + align:start position:0% +the uh with these laass equation + + + align:start position:0% +the uh with these laass equation +Solutions play with some play with some + + align:start position:0% +Solutions play with some play with some + + + align:start position:0% +Solutions play with some play with some +Vector fields that that's my best advice + + align:start position:0% +Vector fields that that's my best advice + + + align:start position:0% +Vector fields that that's my best advice +uh + + align:start position:0% +uh + + + align:start position:0% +uh +and uh + + align:start position:0% +and uh + + + align:start position:0% +and uh +and I'll see you Friday \ No newline at end of file diff --git a/zmzyW1rP-hk.txt b/zmzyW1rP-hk.txt new file mode 100644 index 0000000000000000000000000000000000000000..4e6253abde78bba1ba52b6c7f038c774e24cf729 --- /dev/null +++ b/zmzyW1rP-hk.txt @@ -0,0 +1,2115 @@ +align:start position:0% + +Welcome to this recitation on a face + + align:start position:0% +Welcome to this recitation on a face + + + align:start position:0% +Welcome to this recitation on a face +portrait. So you're given matrix A, a + + align:start position:0% +portrait. So you're given matrix A, a + + + align:start position:0% +portrait. So you're given matrix A, a +2x2 matrix with entries minus one, minus + + align:start position:0% +2x2 matrix with entries minus one, minus + + + align:start position:0% +2x2 matrix with entries minus one, minus +one, one minus C, where C is a constant, + + align:start position:0% +one, one minus C, where C is a constant, + + + align:start position:0% +one, one minus C, where C is a constant, +we will be varying and minus one. As C + + align:start position:0% +we will be varying and minus one. As C + + + align:start position:0% +we will be varying and minus one. As C +increases from zero to other positive + + align:start position:0% +increases from zero to other positive + + + align:start position:0% +increases from zero to other positive +values, determine the path of the system + + align:start position:0% +values, determine the path of the system + + + align:start position:0% +values, determine the path of the system +on the trace determinant diagram that we + + align:start position:0% +on the trace determinant diagram that we + + + align:start position:0% +on the trace determinant diagram that we +saw in previous recitations and draw the + + align:start position:0% +saw in previous recitations and draw the + + + align:start position:0% +saw in previous recitations and draw the +face portraits that corresponds to uh + + align:start position:0% +face portraits that corresponds to uh + + + align:start position:0% +face portraits that corresponds to uh +the critical points uh and the nature of + + align:start position:0% +the critical points uh and the nature of + + + align:start position:0% +the critical points uh and the nature of +the critical points. So here we're + + align:start position:0% +the critical points. So here we're + + + align:start position:0% +the critical points. So here we're +basically talking of a system that would + + align:start position:0% +basically talking of a system that would + + + align:start position:0% +basically talking of a system that would +be a 2x two + + align:start position:0% + + + + align:start position:0% + +system where we have derivative of + + align:start position:0% +system where we have derivative of + + + align:start position:0% +system where we have derivative of +entries xy for vector equals to this + + align:start position:0% +entries xy for vector equals to this + + + align:start position:0% +entries xy for vector equals to this +matrix a c multiplying the unknown uh + + align:start position:0% +matrix a c multiplying the unknown uh + + + align:start position:0% +matrix a c multiplying the unknown uh +vector x c. So take a few minutes and + + align:start position:0% +vector x c. So take a few minutes and + + + align:start position:0% +vector x c. So take a few minutes and +work out through this problem and I'll + + align:start position:0% +work out through this problem and I'll + + + align:start position:0% +work out through this problem and I'll +be right back. + + align:start position:0% + + + + align:start position:0% + +Welcome back. Okay, so I already + + align:start position:0% +Welcome back. Okay, so I already + + + align:start position:0% +Welcome back. Okay, so I already +prepared the trace diagram uh the the + + align:start position:0% +prepared the trace diagram uh the the + + + align:start position:0% +prepared the trace diagram uh the the +trace determined diagram for you. So + + align:start position:0% +trace determined diagram for you. So + + + align:start position:0% +trace determined diagram for you. So +here as a reminder, this is the uh + + align:start position:0% +here as a reminder, this is the uh + + + align:start position:0% +here as a reminder, this is the uh +parabola that determines whether we're + + align:start position:0% +parabola that determines whether we're + + + align:start position:0% +parabola that determines whether we're +going to have repeated a values or not. + + align:start position:0% +going to have repeated a values or not. + + + align:start position:0% +going to have repeated a values or not. +Above this parabola, we have two real + + align:start position:0% +Above this parabola, we have two real + + + align:start position:0% +Above this parabola, we have two real +two complex conjugate values. Below this + + align:start position:0% +two complex conjugate values. Below this + + + align:start position:0% +two complex conjugate values. Below this +parabola we have real values either of + + align:start position:0% +parabola we have real values either of + + + align:start position:0% +parabola we have real values either of +the same signs positive or negative or + + align:start position:0% +the same signs positive or negative or + + + align:start position:0% +the same signs positive or negative or +of different signs. And then we have the + + align:start position:0% +of different signs. And then we have the + + + align:start position:0% +of different signs. And then we have the +borderline cases. In our case here we're + + align:start position:0% +borderline cases. In our case here we're + + + align:start position:0% +borderline cases. In our case here we're +looking at a matrix A + + align:start position:0% +looking at a matrix A + + + align:start position:0% +looking at a matrix A +with a trace equals to -1 + -1 - 1. So + + align:start position:0% +with a trace equals to -1 + -1 - 1. So + + + align:start position:0% +with a trace equals to -1 + -1 - 1. So +it's minus2 and a determinant + + align:start position:0% +it's minus2 and a determinant + + + align:start position:0% +it's minus2 and a determinant +that is equal to 2 - c. So here we are + + align:start position:0% +that is equal to 2 - c. So here we are + + + align:start position:0% +that is equal to 2 - c. So here we are +basically along this dotted line where + + align:start position:0% +basically along this dotted line where + + + align:start position:0% +basically along this dotted line where +the trace equals to minus2. So either + + align:start position:0% +the trace equals to minus2. So either + + + align:start position:0% +the trace equals to minus2. So either +we're going to have complex values with + + align:start position:0% +we're going to have complex values with + + + align:start position:0% +we're going to have complex values with +negative real parts or uh negative agon + + align:start position:0% +negative real parts or uh negative agon + + + align:start position:0% +negative real parts or uh negative agon +value. So we're in stable + + align:start position:0% +value. So we're in stable + + + align:start position:0% +value. So we're in stable +configurations. So we're going to be + + align:start position:0% +configurations. So we're going to be + + + align:start position:0% +configurations. So we're going to be +moving at C equal to zero from a case + + align:start position:0% +moving at C equal to zero from a case + + + align:start position:0% +moving at C equal to zero from a case +where + + align:start position:0% + + + + align:start position:0% + +I'm just going to label this point one + + align:start position:0% +I'm just going to label this point one + + + align:start position:0% +I'm just going to label this point one +from for example we have the matrix + + align:start position:0% +from for example we have the matrix + + + align:start position:0% +from for example we have the matrix +minus one one one minus one with the + + align:start position:0% +minus one one one minus one with the + + + align:start position:0% +minus one one one minus one with the +trace equals to minus2 and the + + align:start position:0% +trace equals to minus2 and the + + + align:start position:0% +trace equals to minus2 and the +determinant equals to two. + + align:start position:0% +determinant equals to two. + + + align:start position:0% +determinant equals to two. +So clearly we're at this point and we + + align:start position:0% +So clearly we're at this point and we + + + align:start position:0% +So clearly we're at this point and we +were we are just going to be increasing + + align:start position:0% +were we are just going to be increasing + + + align:start position:0% +were we are just going to be increasing +the value of C and moving along this + + align:start position:0% +the value of C and moving along this + + + align:start position:0% +the value of C and moving along this +line crossing this first boundary case + + align:start position:0% +line crossing this first boundary case + + + align:start position:0% +line crossing this first boundary case +where we will have uh either defective + + align:start position:0% +where we will have uh either defective + + + align:start position:0% +where we will have uh either defective +or or not case and I'll discuss very + + align:start position:0% +or or not case and I'll discuss very + + + align:start position:0% +or or not case and I'll discuss very +briefly uh what we have and then we have + + align:start position:0% +briefly uh what we have and then we have + + + align:start position:0% +briefly uh what we have and then we have +other value where we are basically in + + align:start position:0% +other value where we are basically in + + + align:start position:0% +other value where we are basically in +this area where we have real values both + + align:start position:0% +this area where we have real values both + + + align:start position:0% +this area where we have real values both +of them negative so we have stability + + align:start position:0% +of them negative so we have stability + + + align:start position:0% +of them negative so we have stability +and it would basically be a sync and + + align:start position:0% +and it would basically be a sync and + + + align:start position:0% +and it would basically be a sync and +then we cross this uh other border line + + align:start position:0% +then we cross this uh other border line + + + align:start position:0% +then we cross this uh other border line +case where the determinant is equal to + + align:start position:0% +case where the determinant is equal to + + + align:start position:0% +case where the determinant is equal to +zero. And here we have one egg value + + align:start position:0% +zero. And here we have one egg value + + + align:start position:0% +zero. And here we have one egg value +that is equal to zero and one that is + + align:start position:0% +that is equal to zero and one that is + + + align:start position:0% +that is equal to zero and one that is +negative and then we get to the the part + + align:start position:0% +negative and then we get to the the part + + + align:start position:0% +negative and then we get to the the part +of the diagram where the determinant is + + align:start position:0% +of the diagram where the determinant is + + + align:start position:0% +of the diagram where the determinant is +negative and the trace is negative and + + align:start position:0% +negative and the trace is negative and + + + align:start position:0% +negative and the trace is negative and +we basically have a saddle uh a saddle + + align:start position:0% +we basically have a saddle uh a saddle + + + align:start position:0% +we basically have a saddle uh a saddle +uh structure where we have one egg in + + align:start position:0% +uh structure where we have one egg in + + + align:start position:0% +uh structure where we have one egg in +value that is negative and another egg + + align:start position:0% +value that is negative and another egg + + + align:start position:0% +value that is negative and another egg +in value that is positive. So let's get + + align:start position:0% +in value that is positive. So let's get + + + align:start position:0% +in value that is positive. So let's get +through these uh five cases and I'll + + align:start position:0% +through these uh five cases and I'll + + + align:start position:0% +through these uh five cases and I'll +just do more detailed picture + + align:start position:0% +just do more detailed picture + + + align:start position:0% +just do more detailed picture +illustrating what I just said. + + align:start position:0% +illustrating what I just said. + + + align:start position:0% +illustrating what I just said. +So I'll just uh write down a bit more in + + align:start position:0% +So I'll just uh write down a bit more in + + + align:start position:0% +So I'll just uh write down a bit more in +detail the first case here. So we have + + align:start position:0% +detail the first case here. So we have + + + align:start position:0% +detail the first case here. So we have +the case where the the the uh the aen + + align:start position:0% +the case where the the the uh the aen + + + align:start position:0% +the case where the the the uh the aen +values are both + + align:start position:0% +values are both + + + align:start position:0% +values are both +complex conjugate and we have their real + + align:start position:0% +complex conjugate and we have their real + + + align:start position:0% +complex conjugate and we have their real +part being negative. So basically we + + align:start position:0% +part being negative. So basically we + + + align:start position:0% +part being negative. So basically we +have spirals, right? + + align:start position:0% + + + + align:start position:0% + +asmtotically + + align:start position:0% +asmtotically + + + align:start position:0% +asmtotically +stable + + align:start position:0% +stable + + + align:start position:0% +stable +spirals and the spirals could be either + + align:start position:0% +spirals and the spirals could be either + + + align:start position:0% +spirals and the spirals could be either +clockwise or counterclockwise. And one + + align:start position:0% +clockwise or counterclockwise. And one + + + align:start position:0% +clockwise or counterclockwise. And one +way of determining + + align:start position:0% + + + + align:start position:0% + +the direction of these spirals is to + + align:start position:0% +the direction of these spirals is to + + + align:start position:0% +the direction of these spirals is to +look at the sign of the velocity vector + + align:start position:0% +look at the sign of the velocity vector + + + align:start position:0% +look at the sign of the velocity vector +of the trajectories in the face. So the + + align:start position:0% +of the trajectories in the face. So the + + + align:start position:0% +of the trajectories in the face. So the +face base basically diagram here where + + align:start position:0% +face base basically diagram here where + + + align:start position:0% +face base basically diagram here where +we have x and y as the axis of the of + + align:start position:0% +we have x and y as the axis of the of + + + align:start position:0% +we have x and y as the axis of the of +this space. So let's look at + + align:start position:0% + + + + align:start position:0% + +oops + + align:start position:0% +oops + + + align:start position:0% +oops +let's look for example at a particular + + align:start position:0% +let's look for example at a particular + + + align:start position:0% +let's look for example at a particular +point here that would be veloc + + align:start position:0% +point here that would be veloc + + + align:start position:0% +point here that would be veloc +and this uh position vector 1 z would + + align:start position:0% +and this uh position vector 1 z would + + + align:start position:0% +and this uh position vector 1 z would +give us a velocity vector uh of minus1 + + align:start position:0% +give us a velocity vector uh of minus1 + + + align:start position:0% +give us a velocity vector uh of minus1 +and plus one. So basically this vector + + align:start position:0% +and plus one. So basically this vector + + + align:start position:0% +and plus one. So basically this vector +would be directed upward which means + + align:start position:0% +would be directed upward which means + + + align:start position:0% +would be directed upward which means +that we are in the case where we would + + align:start position:0% +that we are in the case where we would + + + align:start position:0% +that we are in the case where we would +have a spiral + + align:start position:0% +have a spiral + + + align:start position:0% +have a spiral +coming this way + + align:start position:0% +coming this way + + + align:start position:0% +coming this way +toward + + align:start position:0% +toward + + + align:start position:0% +toward +the critical point and basically with + + align:start position:0% +the critical point and basically with + + + align:start position:0% +the critical point and basically with +the velocity vector here going this way. + + align:start position:0% +the velocity vector here going this way. + + + align:start position:0% +the velocity vector here going this way. +You don't have to actually do all this + + align:start position:0% +You don't have to actually do all this + + + align:start position:0% +You don't have to actually do all this +to figure out which direction of the + + align:start position:0% +to figure out which direction of the + + + align:start position:0% +to figure out which direction of the +spiral you should choose. You can just + + align:start position:0% +spiral you should choose. You can just + + + align:start position:0% +spiral you should choose. You can just +look for these cases 2 x2 matrices at + + align:start position:0% +look for these cases 2 x2 matrices at + + + align:start position:0% +look for these cases 2 x2 matrices at +the entry at the lower left part of your + + align:start position:0% +the entry at the lower left part of your + + + align:start position:0% +the entry at the lower left part of your +matrix and if the coefficient here is + + align:start position:0% +matrix and if the coefficient here is + + + align:start position:0% +matrix and if the coefficient here is +positive then it will determine the + + align:start position:0% +positive then it will determine the + + + align:start position:0% +positive then it will determine the +direction of the uh of the velocity + + align:start position:0% +direction of the uh of the velocity + + + align:start position:0% +direction of the uh of the velocity +vector at this point. So if it's + + align:start position:0% +vector at this point. So if it's + + + align:start position:0% +vector at this point. So if it's +positive in this case you would have + + align:start position:0% +positive in this case you would have + + + align:start position:0% +positive in this case you would have +this counterclockwise uh direction of + + align:start position:0% +this counterclockwise uh direction of + + + align:start position:0% +this counterclockwise uh direction of +rotation of the spiral. Okay. So now we + + align:start position:0% +rotation of the spiral. Okay. So now we + + + align:start position:0% +rotation of the spiral. Okay. So now we +can move on and do the second the + + align:start position:0% +can move on and do the second the + + + align:start position:0% +can move on and do the second the +following cases a bit faster. So the + + align:start position:0% +following cases a bit faster. So the + + + align:start position:0% +following cases a bit faster. So the +second case we are in the case where we + + align:start position:0% +second case we are in the case where we + + + align:start position:0% +second case we are in the case where we +now have two repeated egg values. both + + align:start position:0% +now have two repeated egg values. both + + + align:start position:0% +now have two repeated egg values. both +of them are negative. So we can have + + align:start position:0% +of them are negative. So we can have + + + align:start position:0% +of them are negative. So we can have +either uh a complete case. If we had a + + align:start position:0% +either uh a complete case. If we had a + + + align:start position:0% +either uh a complete case. If we had a +matrix that was diagonal, we would have + + align:start position:0% +matrix that was diagonal, we would have + + + align:start position:0% +matrix that was diagonal, we would have +basically a star. But that's not the + + align:start position:0% +basically a star. But that's not the + + + align:start position:0% +basically a star. But that's not the +case because if we pick for example the + + align:start position:0% +case because if we pick for example the + + + align:start position:0% +case because if we pick for example the +value C equals to one, that puts us on + + align:start position:0% +value C equals to one, that puts us on + + + align:start position:0% +value C equals to one, that puts us on +the parabola. We can see that the matrix + + align:start position:0% +the parabola. We can see that the matrix + + + align:start position:0% +the parabola. We can see that the matrix +AC is not diagonal. So we are in a + + align:start position:0% +AC is not diagonal. So we are in a + + + align:start position:0% +AC is not diagonal. So we are in a +defective case. The defective case + + align:start position:0% +defective case. The defective case + + + align:start position:0% +defective case. The defective case +uh if you compute the AEN uh values in + + align:start position:0% +uh if you compute the AEN uh values in + + + align:start position:0% +uh if you compute the AEN uh values in +AEN vector would give you something that + + align:start position:0% +AEN vector would give you something that + + + align:start position:0% +AEN vector would give you something that +looks like that. The first ray of the + + align:start position:0% +looks like that. The first ray of the + + + align:start position:0% +looks like that. The first ray of the +agon vector corresponding to your uh + + align:start position:0% +agon vector corresponding to your uh + + + align:start position:0% +agon vector corresponding to your uh +agon values would be uh in the direction + + align:start position:0% +agon values would be uh in the direction + + + align:start position:0% +agon values would be uh in the direction +of one zero. We have negative aen + + align:start position:0% +of one zero. We have negative aen + + + align:start position:0% +of one zero. We have negative aen +values. So it's going to zero. And + + align:start position:0% +values. So it's going to zero. And + + + align:start position:0% +values. So it's going to zero. And +basically to determine the direction you + + align:start position:0% +basically to determine the direction you + + + align:start position:0% +basically to determine the direction you +have to see that we're also following a + + align:start position:0% +have to see that we're also following a + + + align:start position:0% +have to see that we're also following a +transition here on the determinant on + + align:start position:0% +transition here on the determinant on + + + align:start position:0% +transition here on the determinant on +the on the trace determinant diagram. + + align:start position:0% +the on the trace determinant diagram. + + + align:start position:0% +the on the trace determinant diagram. +And so basically we will have um a + + align:start position:0% +And so basically we will have um a + + + align:start position:0% +And so basically we will have um a +spiral that would look like this. Um + + align:start position:0% +spiral that would look like this. Um + + + align:start position:0% +spiral that would look like this. Um +yep. + + align:start position:0% +yep. + + + align:start position:0% +yep. +What am I doing? Am I doing the same + + align:start position:0% +What am I doing? Am I doing the same + + + align:start position:0% +What am I doing? Am I doing the same +thing? Yeah. + + align:start position:0% + + + + align:start position:0% + +And it would basically rotate + + align:start position:0% +And it would basically rotate + + + align:start position:0% +And it would basically rotate +as you can see here + + align:start position:0% +as you can see here + + + align:start position:0% +as you can see here +in the same + + align:start position:0% + + + + align:start position:0% + +direction + + align:start position:0% +direction + + + align:start position:0% +direction +as the case that we had just before + + align:start position:0% +as the case that we had just before + + + align:start position:0% +as the case that we had just before +because we basically have the transition + + align:start position:0% +because we basically have the transition + + + align:start position:0% +because we basically have the transition +of the structure of the critical point. + + align:start position:0% +of the structure of the critical point. + + + align:start position:0% +of the structure of the critical point. +Okay. And the arrows are pointing toward + + align:start position:0% +Okay. And the arrows are pointing toward + + + align:start position:0% +Okay. And the arrows are pointing toward +the critical point again because our two + + align:start position:0% +the critical point again because our two + + + align:start position:0% +the critical point again because our two +aen values are uh uh are basically here + + align:start position:0% +aen values are uh uh are basically here + + + align:start position:0% +aen values are uh uh are basically here +negative. which is just a repeated egg + + align:start position:0% +negative. which is just a repeated egg + + + align:start position:0% +negative. which is just a repeated egg +value that is negative. Okay. So now we + + align:start position:0% +value that is negative. Okay. So now we + + + align:start position:0% +value that is negative. Okay. So now we +can move on to a third case where here + + align:start position:0% +can move on to a third case where here + + + align:start position:0% +can move on to a third case where here +we move into the wedge area where we + + align:start position:0% +we move into the wedge area where we + + + align:start position:0% +we move into the wedge area where we +have the two aen values now being real + + align:start position:0% +have the two aen values now being real + + + align:start position:0% +have the two aen values now being real +and uh both of them are negative. + + align:start position:0% +and uh both of them are negative. + + + align:start position:0% +and uh both of them are negative. +So for example + + align:start position:0% +So for example + + + align:start position:0% +So for example +we would have two egg values that would + + align:start position:0% +we would have two egg values that would + + + align:start position:0% +we would have two egg values that would +give us two egg vectors that are + + align:start position:0% +give us two egg vectors that are + + + align:start position:0% +give us two egg vectors that are +basically the rays. The direction of the + + align:start position:0% +basically the rays. The direction of the + + + align:start position:0% +basically the rays. The direction of the +trajectories on these two rays would be + + align:start position:0% +trajectories on these two rays would be + + + align:start position:0% +trajectories on these two rays would be +toward the critical point because we + + align:start position:0% +toward the critical point because we + + + align:start position:0% +toward the critical point because we +have again negative uh a values and uh + + align:start position:0% +have again negative uh a values and uh + + + align:start position:0% +have again negative uh a values and uh +the trajectories then would be following + + align:start position:0% +the trajectories then would be following + + + align:start position:0% +the trajectories then would be following +the uh lambda. So if I for example pick + + align:start position:0% +the uh lambda. So if I for example pick + + + align:start position:0% +the uh lambda. So if I for example pick +lambda one less than lambda 2 + + align:start position:0% +lambda one less than lambda 2 + + + align:start position:0% +lambda one less than lambda 2 +then I would have something like this + + align:start position:0% +then I would have something like this + + + align:start position:0% +then I would have something like this +going to zero + + align:start position:0% + + + + align:start position:0% + +and we would have this trajectory + + align:start position:0% +and we would have this trajectory + + + align:start position:0% +and we would have this trajectory +corresponding + + align:start position:0% +corresponding + + + align:start position:0% +corresponding +to the value that is the closer to zero. + + align:start position:0% +to the value that is the closer to zero. + + + align:start position:0% +to the value that is the closer to zero. +Okay. And again the arrows would be + + align:start position:0% +Okay. And again the arrows would be + + + align:start position:0% +Okay. And again the arrows would be +going toward this critical point. So we + + align:start position:0% +going toward this critical point. So we + + + align:start position:0% +going toward this critical point. So we +can now move on and if we keep + + align:start position:0% +can now move on and if we keep + + + align:start position:0% +can now move on and if we keep +increasing C uh we reach now the point + + align:start position:0% +increasing C uh we reach now the point + + + align:start position:0% +increasing C uh we reach now the point +four where we are in the special case + + align:start position:0% +four where we are in the special case + + + align:start position:0% +four where we are in the special case +again a boundary case where the + + align:start position:0% +again a boundary case where the + + + align:start position:0% +again a boundary case where the +determinant is zero but the trace is non + + align:start position:0% +determinant is zero but the trace is non + + + align:start position:0% +determinant is zero but the trace is non +zero. If the terminant is zero which is + + align:start position:0% +zero. If the terminant is zero which is + + + align:start position:0% +zero. If the terminant is zero which is +the product of the two aen values it + + align:start position:0% +the product of the two aen values it + + + align:start position:0% +the product of the two aen values it +means that we have one a value that is + + align:start position:0% +means that we have one a value that is + + + align:start position:0% +means that we have one a value that is +equal to zero + + align:start position:0% +equal to zero + + + align:start position:0% +equal to zero +and another aen value that is actually + + align:start position:0% +and another aen value that is actually + + + align:start position:0% +and another aen value that is actually +in this case minus two. So just + + align:start position:0% +in this case minus two. So just + + + align:start position:0% +in this case minus two. So just +negative. So what happens here? uh what + + align:start position:0% +negative. So what happens here? uh what + + + align:start position:0% +negative. So what happens here? uh what +happens is that we have now + + align:start position:0% +happens is that we have now + + + align:start position:0% +happens is that we have now +the aen vector that corresponds to the + + align:start position:0% +the aen vector that corresponds to the + + + align:start position:0% +the aen vector that corresponds to the +egg value equals to zero is basically + + align:start position:0% +egg value equals to zero is basically + + + align:start position:0% +egg value equals to zero is basically +just defining a whole line of critical + + align:start position:0% +just defining a whole line of critical + + + align:start position:0% +just defining a whole line of critical +points. So all the points on this line + + align:start position:0% +points. So all the points on this line + + + align:start position:0% +points. So all the points on this line +that would correspond so for example to + + align:start position:0% +that would correspond so for example to + + + align:start position:0% +that would correspond so for example to +lambda zero are all critical points. So + + align:start position:0% +lambda zero are all critical points. So + + + align:start position:0% +lambda zero are all critical points. So +we don't need to actually draw arrows + + align:start position:0% +we don't need to actually draw arrows + + + align:start position:0% +we don't need to actually draw arrows +here. All the points would be critical + + align:start position:0% +here. All the points would be critical + + + align:start position:0% +here. All the points would be critical +points. And another direction or ray + + align:start position:0% +points. And another direction or ray + + + align:start position:0% +points. And another direction or ray +would be determined by the second egg + + align:start position:0% +would be determined by the second egg + + + align:start position:0% +would be determined by the second egg +value lambda 2. And uh we would have for + + align:start position:0% +value lambda 2. And uh we would have for + + + align:start position:0% +value lambda 2. And uh we would have for +example + + align:start position:0% +example + + + align:start position:0% +example +directions + + align:start position:0% +directions + + + align:start position:0% +directions +uh in this way that would correspond to + + align:start position:0% +uh in this way that would correspond to + + + align:start position:0% +uh in this way that would correspond to +direction of v2. So all these would be + + align:start position:0% +direction of v2. So all these would be + + + align:start position:0% +direction of v2. So all these would be +parallel to v2 and we would have the + + align:start position:0% +parallel to v2 and we would have the + + + align:start position:0% +parallel to v2 and we would have the +trajectories + + align:start position:0% + + + + align:start position:0% + +going toward all the critical points on + + align:start position:0% +going toward all the critical points on + + + align:start position:0% +going toward all the critical points on +this line. So in this case we're in a + + align:start position:0% +this line. So in this case we're in a + + + align:start position:0% +this line. So in this case we're in a +case where we actually don't have one + + align:start position:0% +case where we actually don't have one + + + align:start position:0% +case where we actually don't have one +localized critical points like in the + + align:start position:0% +localized critical points like in the + + + align:start position:0% +localized critical points like in the +previous case that we saw we actually + + align:start position:0% +previous case that we saw we actually + + + align:start position:0% +previous case that we saw we actually +have a full a whole line of critical + + align:start position:0% +have a full a whole line of critical + + + align:start position:0% +have a full a whole line of critical +points. Okay. So let's move one more + + align:start position:0% +points. Okay. So let's move one more + + + align:start position:0% +points. Okay. So let's move one more +point down. So here for another value of + + align:start position:0% +point down. So here for another value of + + + align:start position:0% +point down. So here for another value of +C. We now are in the lower part of the + + align:start position:0% +C. We now are in the lower part of the + + + align:start position:0% +C. We now are in the lower part of the +diagram where we now have two values are + + align:start position:0% +diagram where we now have two values are + + + align:start position:0% +diagram where we now have two values are +again real but now the determinant is + + align:start position:0% +again real but now the determinant is + + + align:start position:0% +again real but now the determinant is +negative. Determinant is the product of + + align:start position:0% +negative. Determinant is the product of + + + align:start position:0% +negative. Determinant is the product of +the two. So basically you know that one + + align:start position:0% +the two. So basically you know that one + + + align:start position:0% +the two. So basically you know that one +is positive and the other one is + + align:start position:0% +is positive and the other one is + + + align:start position:0% +is positive and the other one is +negative. Okay. So for example here we + + align:start position:0% +negative. Okay. So for example here we + + + align:start position:0% +negative. Okay. So for example here we +would have + + align:start position:0% + + + + align:start position:0% + +uh one positive + + align:start position:0% +uh one positive + + + align:start position:0% +uh one positive +the negative aen uh value. + + align:start position:0% +the negative aen uh value. + + + align:start position:0% +the negative aen uh value. +Oops sorry. Thank you. + + align:start position:0% + + + + align:start position:0% + +So we would have the positive aen value + + align:start position:0% +So we would have the positive aen value + + + align:start position:0% +So we would have the positive aen value +and the negative aen value here. So here + + align:start position:0% +and the negative aen value here. So here + + + align:start position:0% +and the negative aen value here. So here +again we're just moving in the structure + + align:start position:0% +again we're just moving in the structure + + + align:start position:0% +again we're just moving in the structure +of the a of the uh critical point. So we + + align:start position:0% +of the a of the uh critical point. So we + + + align:start position:0% +of the a of the uh critical point. So we +should have a smooth transition between + + align:start position:0% +should have a smooth transition between + + + align:start position:0% +should have a smooth transition between +the diagrams going one to five. And so + + align:start position:0% +the diagrams going one to five. And so + + + align:start position:0% +the diagrams going one to five. And so +here what we see is that we actually + + align:start position:0% +here what we see is that we actually + + + align:start position:0% +here what we see is that we actually +have uh the array that is basically the + + align:start position:0% +have uh the array that is basically the + + + align:start position:0% +have uh the array that is basically the +stable the spa stable space here that + + align:start position:0% +stable the spa stable space here that + + + align:start position:0% +stable the spa stable space here that +would uh give us the trajectories going + + align:start position:0% +would uh give us the trajectories going + + + align:start position:0% +would uh give us the trajectories going +to zero. But it's the only air region + + align:start position:0% +to zero. But it's the only air region + + + align:start position:0% +to zero. But it's the only air region +where we have stability and all the + + align:start position:0% +where we have stability and all the + + + align:start position:0% +where we have stability and all the +trajectories would just then be + + align:start position:0% + + + + align:start position:0% + +tangent in minus infinity to the the + + align:start position:0% +tangent in minus infinity to the the + + + align:start position:0% +tangent in minus infinity to the the +array v1 corresponding to uh the + + align:start position:0% +array v1 corresponding to uh the + + + align:start position:0% +array v1 corresponding to uh the +negative aen value and going toward the + + align:start position:0% +negative aen value and going toward the + + + align:start position:0% +negative aen value and going toward the +direction of the ray with the positive + + align:start position:0% +direction of the ray with the positive + + + align:start position:0% +direction of the ray with the positive +aen uh value at plus infinity. Okay. So + + align:start position:0% +aen uh value at plus infinity. Okay. So + + + align:start position:0% +aen uh value at plus infinity. Okay. So +we would have + + align:start position:0% +we would have + + + align:start position:0% +we would have +something like that that would + + align:start position:0% +something like that that would + + + align:start position:0% +something like that that would +correspond to a saddle. + + align:start position:0% + + + + align:start position:0% + +This would be a comp. + + align:start position:0% +This would be a comp. + + + align:start position:0% +This would be a comp. +This is basically a sink + + align:start position:0% +This is basically a sink + + + align:start position:0% +This is basically a sink +or basically a stable node. This would + + align:start position:0% +or basically a stable node. This would + + + align:start position:0% +or basically a stable node. This would +be defective + + align:start position:0% +be defective + + + align:start position:0% +be defective +stable node. + + align:start position:0% +stable node. + + + align:start position:0% +stable node. +And here we just have a astoically + + align:start position:0% +And here we just have a astoically + + + align:start position:0% +And here we just have a astoically +stable + + align:start position:0% +stable + + + align:start position:0% +stable +spiral. So uh basically here what you + + align:start position:0% +spiral. So uh basically here what you + + + align:start position:0% +spiral. So uh basically here what you +could see is that we have uh by just + + align:start position:0% +could see is that we have uh by just + + + align:start position:0% +could see is that we have uh by just +changing the value of the constant C had + + align:start position:0% +changing the value of the constant C had + + + align:start position:0% +changing the value of the constant C had +um moved this the the structure of the + + align:start position:0% +um moved this the the structure of the + + + align:start position:0% +um moved this the the structure of the +critical point for the of the system + + align:start position:0% +critical point for the of the system + + + align:start position:0% +critical point for the of the system +from the phase diagrams one to five and + + align:start position:0% +from the phase diagrams one to five and + + + align:start position:0% +from the phase diagrams one to five and +the transitions can be seen to be smooth + + align:start position:0% +the transitions can be seen to be smooth + + + align:start position:0% +the transitions can be seen to be smooth +if you had a continuum of values of for + + align:start position:0% +if you had a continuum of values of for + + + align:start position:0% +if you had a continuum of values of for +C. So that ends this recitation. \ No newline at end of file diff --git a/zsxqmbdUXuo.txt b/zsxqmbdUXuo.txt new file mode 100644 index 0000000000000000000000000000000000000000..41ddf6397ddc5e83f588ff7bdf9d5c8ff242018d --- /dev/null +++ b/zsxqmbdUXuo.txt @@ -0,0 +1,10200 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT OpenCourseWare continue to + + align:start position:0% +will help MIT OpenCourseWare continue to + + + align:start position:0% +will help MIT OpenCourseWare continue to +offer high quality educational resources + + align:start position:0% +offer high quality educational resources + + + align:start position:0% +offer high quality educational resources +for free to make a donation or view + + align:start position:0% +for free to make a donation or view + + + align:start position:0% +for free to make a donation or view +additional materials from hundreds of + + align:start position:0% +additional materials from hundreds of + + + align:start position:0% +additional materials from hundreds of +MIT courses visit MIT opencourseware at + + align:start position:0% +MIT courses visit MIT opencourseware at + + + align:start position:0% +MIT courses visit MIT opencourseware at +ocw.mit.edu + + align:start position:0% +ocw.mit.edu + + + align:start position:0% +ocw.mit.edu +ok + + align:start position:0% + + + + align:start position:0% + +one + + align:start position:0% +one + + + align:start position:0% +one +of the really important things in this + + align:start position:0% +of the really important things in this + + + align:start position:0% +of the really important things in this +course on spectroscopy is being able to + + align:start position:0% +course on spectroscopy is being able to + + + align:start position:0% +course on spectroscopy is being able to +write effective hamiltonians to describe + + align:start position:0% +write effective hamiltonians to describe + + + align:start position:0% +write effective hamiltonians to describe +the problem that you're going to be + + align:start position:0% +the problem that you're going to be + + + align:start position:0% +the problem that you're going to be +solving and so at the beginning I'm + + align:start position:0% +solving and so at the beginning I'm + + + align:start position:0% +solving and so at the beginning I'm +doing an exercise and I in two versions + + align:start position:0% +doing an exercise and I in two versions + + + align:start position:0% +doing an exercise and I in two versions +of effective Hamiltonian before starting + + align:start position:0% +of effective Hamiltonian before starting + + + align:start position:0% +of effective Hamiltonian before starting +to pick up the material of spectroscopy + + align:start position:0% +to pick up the material of spectroscopy + + + align:start position:0% +to pick up the material of spectroscopy +in a logical order and so it's it's + + align:start position:0% +in a logical order and so it's it's + + + align:start position:0% +in a logical order and so it's it's +a taste of what's to come it's an + + align:start position:0% +a taste of what's to come it's an + + + align:start position:0% +a taste of what's to come it's an +example of the kind of problems I hope + + align:start position:0% +example of the kind of problems I hope + + + align:start position:0% +example of the kind of problems I hope +you'll be able to to solve and like + + align:start position:0% +you'll be able to to solve and like + + + align:start position:0% +you'll be able to to solve and like +solving and I said there was a problem + + align:start position:0% +solving and I said there was a problem + + + align:start position:0% +solving and I said there was a problem +last time the problem is described at + + align:start position:0% +last time the problem is described at + + + align:start position:0% +last time the problem is described at +the top of the first page now probably + + align:start position:0% + + + + align:start position:0% + +the best thing would be for you to + + align:start position:0% +the best thing would be for you to + + + align:start position:0% +the best thing would be for you to +submit that answer to me on Friday on + + align:start position:0% +submit that answer to me on Friday on + + + align:start position:0% +submit that answer to me on Friday on +Thursday or to one of the members of my + + align:start position:0% +Thursday or to one of the members of my + + + align:start position:0% +Thursday or to one of the members of my +group if you're and but I'm mostly going + + align:start position:0% +group if you're and but I'm mostly going + + + align:start position:0% +group if you're and but I'm mostly going +to look at this just to say oh yeah you + + align:start position:0% +to look at this just to say oh yeah you + + + align:start position:0% +to look at this just to say oh yeah you +did it and I my idea is that you're + + align:start position:0% +did it and I my idea is that you're + + + align:start position:0% +did it and I my idea is that you're +going to do these problems just to sort + + align:start position:0% +going to do these problems just to sort + + + align:start position:0% +going to do these problems just to sort +of refresh + + align:start position:0% +of refresh + + + align:start position:0% +of refresh +your memory of perturbation theory and + + align:start position:0% +your memory of perturbation theory and + + + align:start position:0% +your memory of perturbation theory and +get a little bit insane + + align:start position:0% +get a little bit insane + + + align:start position:0% +get a little bit insane +with the awful algebra that ensues okay + + align:start position:0% +with the awful algebra that ensues okay + + + align:start position:0% +with the awful algebra that ensues okay +so + + align:start position:0% + + + + align:start position:0% + +the + + align:start position:0% +the + + + align:start position:0% +the +the problem that I wanted you to do is a + + align:start position:0% +the problem that I wanted you to do is a + + + align:start position:0% +the problem that I wanted you to do is a +diatomic molecule and + + align:start position:0% +diatomic molecule and + + + align:start position:0% +diatomic molecule and +it's a vibrating + + align:start position:0% +it's a vibrating + + + align:start position:0% +it's a vibrating +rotor + + align:start position:0% + + + + align:start position:0% + +and so + + align:start position:0% + + + + align:start position:0% + +we have a potential and + + align:start position:0% +we have a potential and + + + align:start position:0% +we have a potential and +the potential is got the harmonic term I + + align:start position:0% +the potential is got the harmonic term I + + + align:start position:0% +the potential is got the harmonic term I +just + + align:start position:0% +just + + + align:start position:0% +just +want to make sure and then + + align:start position:0% +want to make sure and then + + + align:start position:0% +want to make sure and then +a cubic + + align:start position:0% +a cubic + + + align:start position:0% +a cubic +term and + + align:start position:0% +term and + + + align:start position:0% +term and +a quartic term so + + align:start position:0% +a quartic term so + + + align:start position:0% +a quartic term so +these are the operators that you're + + align:start position:0% +these are the operators that you're + + + align:start position:0% +these are the operators that you're +going to be dealing with using + + align:start position:0% +going to be dealing with using + + + align:start position:0% +going to be dealing with using +perturbation theory and we + + align:start position:0% +perturbation theory and we + + + align:start position:0% +perturbation theory and we +also have the rotational operator which + + align:start position:0% +also have the rotational operator which + + + align:start position:0% +also have the rotational operator which +is the moment of inertia operator and + + align:start position:0% +is the moment of inertia operator and + + + align:start position:0% +is the moment of inertia operator and +that's H bar squared over H see that's + + align:start position:0% +that's H bar squared over H see that's + + + align:start position:0% +that's H bar squared over H see that's +just because if the units were using and + + align:start position:0% +just because if the units were using and + + + align:start position:0% +just because if the units were using and +it's 1 over 2 mu R + + align:start position:0% +it's 1 over 2 mu R + + + align:start position:0% +it's 1 over 2 mu R +squared and I'm going to convert our + + align:start position:0% +squared and I'm going to convert our + + + align:start position:0% +squared and I'm going to convert our +into Q in a moment but this is just + + align:start position:0% +into Q in a moment but this is just + + + align:start position:0% +into Q in a moment but this is just +analogous to the the kinetic energy + + align:start position:0% +analogous to the the kinetic energy + + + align:start position:0% +analogous to the the kinetic energy +operator 1 over 2m a + + align:start position:0% +operator 1 over 2m a + + + align:start position:0% +operator 1 over 2m a +P + + align:start position:0% +P + + + align:start position:0% +P +squared over 2m and the the we get a J + + align:start position:0% +squared over 2m and the the we get a J + + + align:start position:0% +squared over 2m and the the we get a J +squared here okay so we + + align:start position:0% +squared here okay so we + + + align:start position:0% +squared here okay so we +we write B of our by saying r + + align:start position:0% +we write B of our by saying r + + + align:start position:0% +we write B of our by saying r +minus r e SQ rewrite be of our and we do + + align:start position:0% +minus r e SQ rewrite be of our and we do + + + align:start position:0% +minus r e SQ rewrite be of our and we do +a power series expansion and we get the + + align:start position:0% +a power series expansion and we get the + + + align:start position:0% +a power series expansion and we get the +e1 + + align:start position:0% +e1 + + + align:start position:0% +e1 +minus 2q + + align:start position:0% +minus 2q + + + align:start position:0% +minus 2q +over r-e + 3 + + align:start position:0% +over r-e + 3 + + + align:start position:0% +over r-e + 3 +q / r e squared so the problem we're + + align:start position:0% +q / r e squared so the problem we're + + + align:start position:0% +q / r e squared so the problem we're +going to solve that you're going to + + align:start position:0% +going to solve that you're going to + + + align:start position:0% +going to solve that you're going to +solve involves cute squared QQQ fourth + + align:start position:0% +solve involves cute squared QQQ fourth + + + align:start position:0% +solve involves cute squared QQQ fourth +and cue to the one Q squared and we're + + align:start position:0% +and cue to the one Q squared and we're + + + align:start position:0% +and cue to the one Q squared and we're +going to put that all together in a way + + align:start position:0% +going to put that all together in a way + + + align:start position:0% +going to put that all together in a way +that relay gives you something thats + + align:start position:0% +that relay gives you something thats + + + align:start position:0% +that relay gives you something thats +related to the energy levels of + + align:start position:0% +related to the energy levels of + + + align:start position:0% +related to the energy levels of +a diatomic molecule so + + align:start position:0% + + + + align:start position:0% + +the energy levels for a diatomic + + align:start position:0% +the energy levels for a diatomic + + + align:start position:0% +the energy levels for a diatomic +molecule they + + align:start position:0% +molecule they + + + align:start position:0% +molecule they +have two quantum numbers v + j actually + + align:start position:0% +have two quantum numbers v + j actually + + + align:start position:0% +have two quantum numbers v + j actually +you'll see that they have omega and + + align:start position:0% +you'll see that they have omega and + + + align:start position:0% +you'll see that they have omega and +lambda s and sigma and other things + + align:start position:0% +lambda s and sigma and other things + + + align:start position:0% +lambda s and sigma and other things +later but for an ordinary molecule + + align:start position:0% +later but for an ordinary molecule + + + align:start position:0% +later but for an ordinary molecule +without any angular momenta any + + align:start position:0% +without any angular momenta any + + + align:start position:0% +without any angular momenta any +electronic an angular momentum we + + align:start position:0% +electronic an angular momentum we + + + align:start position:0% +electronic an angular momentum we +write the energy levels in a in a naive + + align:start position:0% +write the energy levels in a in a naive + + + align:start position:0% +write the energy levels in a in a naive +way I got + + align:start position:0% + + + + align:start position:0% + +this wrong last yesterday and then we + + align:start position:0% +this wrong last yesterday and then we + + + align:start position:0% +this wrong last yesterday and then we +have plus j j plus 1 times B times okay + + align:start position:0% + + + + align:start position:0% + +sorry ve minus + + align:start position:0% +sorry ve minus + + + align:start position:0% +sorry ve minus +alpha e e plus a half plus + + align:start position:0% +alpha e e plus a half plus + + + align:start position:0% +alpha e e plus a half plus +gamma e a plus a half squared and + + align:start position:0% +gamma e a plus a half squared and + + + align:start position:0% +gamma e a plus a half squared and +continues + + align:start position:0% + + + + align:start position:0% + +and then we have plus minus J a square + + align:start position:0% +and then we have plus minus J a square + + + align:start position:0% +and then we have plus minus J a square +J plus 1 squared d + + align:start position:0% +J plus 1 squared d + + + align:start position:0% +J plus 1 squared d +e plus beta e plus + + align:start position:0% +e plus beta e plus + + + align:start position:0% +e plus beta e plus +a half so you see what we have is a + + align:start position:0% +a half so you see what we have is a + + + align:start position:0% +a half so you see what we have is a +bunch of expansions and powers of e plus + + align:start position:0% +bunch of expansions and powers of e plus + + + align:start position:0% +bunch of expansions and powers of e plus +a half and JJ + + align:start position:0% +a half and JJ + + + align:start position:0% +a half and JJ ++ 1 and so + + align:start position:0% ++ 1 and so + + + align:start position:0% ++ 1 and so +in order to describe the energy levels + + align:start position:0% +in order to describe the energy levels + + + align:start position:0% +in order to describe the energy levels +of a molecule or + + align:start position:0% +of a molecule or + + + align:start position:0% +of a molecule or +the problem that I've asked you to solve + + align:start position:0% +the problem that I've asked you to solve + + + align:start position:0% +the problem that I've asked you to solve +you want to get omega omega XE be alpha + + align:start position:0% +you want to get omega omega XE be alpha + + + align:start position:0% +you want to get omega omega XE be alpha +e and de from the + + align:start position:0% +e and de from the + + + align:start position:0% +e and de from the +quantities k ay B + + align:start position:0% +quantities k ay B + + + align:start position:0% +quantities k ay B +mu + + align:start position:0% + + + + align:start position:0% + +so we + + align:start position:0% +so we + + + align:start position:0% +so we +we + + align:start position:0% +we + + + align:start position:0% +we +have the harmonic the cubic the quartic + + align:start position:0% +have the harmonic the cubic the quartic + + + align:start position:0% +have the harmonic the cubic the quartic +and the mass and that will enable you to + + align:start position:0% +and the mass and that will enable you to + + + align:start position:0% +and the mass and that will enable you to +derive values for the things that you'd + + align:start position:0% +derive values for the things that you'd + + + align:start position:0% +derive values for the things that you'd +actually observe in the spectrum you + + align:start position:0% +actually observe in the spectrum you + + + align:start position:0% +actually observe in the spectrum you +could carry this further and get ye and + + align:start position:0% +could carry this further and get ye and + + + align:start position:0% +could carry this further and get ye and +gamma e but I'm not too cruel and so + + align:start position:0% +gamma e but I'm not too cruel and so + + + align:start position:0% +gamma e but I'm not too cruel and so +that's the problem and okay + + align:start position:0% +that's the problem and okay + + + align:start position:0% +that's the problem and okay +so let me go the other board so + + align:start position:0% + + + + align:start position:0% + +what do we do how do we use perturbation + + align:start position:0% +what do we do how do we use perturbation + + + align:start position:0% +what do we do how do we use perturbation +theory now this is really a lengthy + + align:start position:0% +theory now this is really a lengthy + + + align:start position:0% +theory now this is really a lengthy +review of what we did last time but it's + + align:start position:0% +review of what we did last time but it's + + + align:start position:0% +review of what we did last time but it's +still better to see it we + + align:start position:0% +still better to see it we + + + align:start position:0% +still better to see it we +expanded the Hamiltonian into a zero + + align:start position:0% +expanded the Hamiltonian into a zero + + + align:start position:0% +expanded the Hamiltonian into a zero +order part and a perturbation part we'd + + align:start position:0% +order part and a perturbation part we'd + + + align:start position:0% +order part and a perturbation part we'd +expended the energy into a zero order + + align:start position:0% +expended the energy into a zero order + + + align:start position:0% +expended the energy into a zero order +part which is I ghen values of H 0 and + + align:start position:0% +part which is I ghen values of H 0 and + + + align:start position:0% +part which is I ghen values of H 0 and +first order and second order etc and so + + align:start position:0% +first order and second order etc and so + + + align:start position:0% +first order and second order etc and so +we got zero + + align:start position:0% +we got zero + + + align:start position:0% +we got zero +order equation + + align:start position:0% +order equation + + + align:start position:0% +order equation +and + + align:start position:0% + + + + align:start position:0% + +this is what we use to describe to + + align:start position:0% + + + + align:start position:0% + +define our wave functions our wave + + align:start position:0% +define our wave functions our wave + + + align:start position:0% +define our wave functions our wave +functions are eigenfunctions of the + + align:start position:0% +functions are eigenfunctions of the + + + align:start position:0% +functions are eigenfunctions of the +hamel the zero-order hamiltonian the + + align:start position:0% +hamel the zero-order hamiltonian the + + + align:start position:0% +hamel the zero-order hamiltonian the +energy levels are the eigenvalues and + + align:start position:0% +energy levels are the eigenvalues and + + + align:start position:0% +energy levels are the eigenvalues and +there are many choices of h0 it's + + align:start position:0% +there are many choices of h0 it's + + + align:start position:0% +there are many choices of h0 it's +usually not necessary to make your + + align:start position:0% +usually not necessary to make your + + + align:start position:0% +usually not necessary to make your +choice of h0 read the mind of the + + align:start position:0% +choice of h0 read the mind of the + + + align:start position:0% +choice of h0 read the mind of the +molecule it's just usually you tues 80 + + align:start position:0% +molecule it's just usually you tues 80 + + + align:start position:0% +molecule it's just usually you tues 80 +because it gives you things that you can + + align:start position:0% +because it gives you things that you can + + + align:start position:0% +because it gives you things that you can +do without breaking a sweat as far as + + align:start position:0% +do without breaking a sweat as far as + + + align:start position:0% +do without breaking a sweat as far as +writing down values of matrix elements + + align:start position:0% +writing down values of matrix elements + + + align:start position:0% +writing down values of matrix elements +once you've written down values of + + align:start position:0% +once you've written down values of + + + align:start position:0% +once you've written down values of +matrix elements the computer does all + + align:start position:0% +matrix elements the computer does all + + + align:start position:0% +matrix elements the computer does all +the work and it's nice to be able to + + align:start position:0% +the work and it's nice to be able to + + + align:start position:0% +the work and it's nice to be able to +have a way of writing the matrix + + align:start position:0% +have a way of writing the matrix + + + align:start position:0% +have a way of writing the matrix +elements which really don't even require + + align:start position:0% +elements which really don't even require + + + align:start position:0% +elements which really don't even require +you to write them you say mr. computer + + align:start position:0% +you to write them you say mr. computer + + + align:start position:0% +you to write them you say mr. computer +you write them because they are gotten + + align:start position:0% +you write them because they are gotten + + + align:start position:0% +you write them because they are gotten +by this simple formula + + align:start position:0% +by this simple formula + + + align:start position:0% +by this simple formula +so but + + align:start position:0% +so but + + + align:start position:0% +so but +you don't have to do that this h0 is + + align:start position:0% +you don't have to do that this h0 is + + + align:start position:0% +you don't have to do that this h0 is +whatever you like but it and it provides + + align:start position:0% +whatever you like but it and it provides + + + align:start position:0% +whatever you like but it and it provides +the words you use and the images you use + + align:start position:0% +the words you use and the images you use + + + align:start position:0% +the words you use and the images you use +to describe what you're seeing in the + + align:start position:0% +to describe what you're seeing in the + + + align:start position:0% +to describe what you're seeing in the +experiment and sometimes + + align:start position:0% +experiment and sometimes + + + align:start position:0% +experiment and sometimes +that's valuable it also provides you + + align:start position:0% +that's valuable it also provides you + + + align:start position:0% +that's valuable it also provides you +with a starting point when you start out + + align:start position:0% +with a starting point when you start out + + + align:start position:0% +with a starting point when you start out +in interpreting an experiment you have + + align:start position:0% +in interpreting an experiment you have + + + align:start position:0% +in interpreting an experiment you have +energy levels and they don't come with + + align:start position:0% +energy levels and they don't come with + + + align:start position:0% +energy levels and they don't come with +any hints on them about well they + + align:start position:0% +any hints on them about well they + + + align:start position:0% +any hints on them about well they +usually don't come with many hints on + + align:start position:0% +usually don't come with many hints on + + + align:start position:0% +usually don't come with many hints on +them what they mean and your + + align:start position:0% +them what they mean and your + + + align:start position:0% +them what they mean and your +job is to somehow recognize the patterns + + align:start position:0% +job is to somehow recognize the patterns + + + align:start position:0% +job is to somehow recognize the patterns +in the real spectrum and relate those + + align:start position:0% +in the real spectrum and relate those + + + align:start position:0% +in the real spectrum and relate those +patterns to the + + align:start position:0% +patterns to the + + + align:start position:0% +patterns to the +truth and that's a non trivial matter + + align:start position:0% +truth and that's a non trivial matter + + + align:start position:0% +truth and that's a non trivial matter +and so if you have a good 801 that does + + align:start position:0% +and so if you have a good 801 that does + + + align:start position:0% +and so if you have a good 801 that does +mimic what the molecule the way the + + align:start position:0% +mimic what the molecule the way the + + + align:start position:0% +mimic what the molecule the way the +molecule things you will have a much + + align:start position:0% +molecule things you will have a much + + + align:start position:0% +molecule things you will have a much +easier job of making sense of the + + align:start position:0% +easier job of making sense of the + + + align:start position:0% +easier job of making sense of the +experiment then if you have a bad one + + align:start position:0% +experiment then if you have a bad one + + + align:start position:0% +experiment then if you have a bad one +but that's counterbalanced by wanting to + + align:start position:0% +but that's counterbalanced by wanting to + + + align:start position:0% +but that's counterbalanced by wanting to +have the computer essentially + + align:start position:0% +have the computer essentially + + + align:start position:0% +have the computer essentially +do all the work so you have to make a + + align:start position:0% +do all the work so you have to make a + + + align:start position:0% +do all the work so you have to make a +compromise ok so we choose this that + + align:start position:0% +compromise ok so we choose this that + + + align:start position:0% +compromise ok so we choose this that +defines basis States the + + align:start position:0% +defines basis States the + + + align:start position:0% +defines basis States the +h0 for a diatomic molecule is a harmonic + + align:start position:0% +h0 for a diatomic molecule is a harmonic + + + align:start position:0% +h0 for a diatomic molecule is a harmonic +oscillator plus + + align:start position:0% +oscillator plus + + + align:start position:0% +oscillator plus +a rigid rotor and so 80 is I + + align:start position:0% +a rigid rotor and so 80 is I + + + align:start position:0% +a rigid rotor and so 80 is I +can + + align:start position:0% +can + + + align:start position:0% +can +never remember where the + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% + + + + align:start position:0% + +that's the zero-order Hamiltonian rigid + + align:start position:0% +that's the zero-order Hamiltonian rigid + + + align:start position:0% +that's the zero-order Hamiltonian rigid +rotor because it's a constant and + + align:start position:0% +rotor because it's a constant and + + + align:start position:0% +rotor because it's a constant and +harmonic oscillator and so + + align:start position:0% +harmonic oscillator and so + + + align:start position:0% +harmonic oscillator and so +the zero-order energy levels r omega e + + align:start position:0% +the zero-order energy levels r omega e + + + align:start position:0% +the zero-order energy levels r omega e +EV + f plus + + align:start position:0% +EV + f plus + + + align:start position:0% +EV + f plus +de JJ + 1 well + + align:start position:0% +de JJ + 1 well + + + align:start position:0% +de JJ + 1 well +gives + + align:start position:0% +gives + + + align:start position:0% +gives +you ev0 + + align:start position:0% +you ev0 + + + align:start position:0% +you ev0 +j + + align:start position:0% +j + + + align:start position:0% +j +is equal to that and you get I ghen + + align:start position:0% +is equal to that and you get I ghen + + + align:start position:0% +is equal to that and you get I ghen +functions which are the and j + + align:start position:0% +functions which are the and j + + + align:start position:0% +functions which are the and j +MJ and those + + align:start position:0% +MJ and those + + + align:start position:0% +MJ and those +are your those are the things that you + + align:start position:0% +are your those are the things that you + + + align:start position:0% +are your those are the things that you +manipulate but one of the things about + + align:start position:0% +manipulate but one of the things about + + + align:start position:0% +manipulate but one of the things about +matrix mechanics which is making it + + align:start position:0% +matrix mechanics which is making it + + + align:start position:0% +matrix mechanics which is making it +really beautiful is that you never + + align:start position:0% +really beautiful is that you never + + + align:start position:0% +really beautiful is that you never +unpack these things you never asked well + + align:start position:0% +unpack these things you never asked well + + + align:start position:0% +unpack these things you never asked well +what are these functions these are + + align:start position:0% +what are these functions these are + + + align:start position:0% +what are these functions these are +labels of states in some abstract space + + align:start position:0% +labels of states in some abstract space + + + align:start position:0% +labels of states in some abstract space +and they have certain properties that + + align:start position:0% +and they have certain properties that + + + align:start position:0% +and they have certain properties that +you can write down there matrix elements + + align:start position:0% +you can write down there matrix elements + + + align:start position:0% +you can write down there matrix elements +without thinking about them and you + + align:start position:0% +without thinking about them and you + + + align:start position:0% +without thinking about them and you +almost never look at what the functions + + align:start position:0% +almost never look at what the functions + + + align:start position:0% +almost never look at what the functions +are in fact this is actually not a + + align:start position:0% +are in fact this is actually not a + + + align:start position:0% +are in fact this is actually not a +function to make this a function you + + align:start position:0% +function to make this a function you + + + align:start position:0% +function to make this a function you +have to write this quantity here but + + align:start position:0% +have to write this quantity here but + + + align:start position:0% +have to write this quantity here but +it is wonderful one of the wonderful + + align:start position:0% +it is wonderful one of the wonderful + + + align:start position:0% +it is wonderful one of the wonderful +things about matrix mechanics is you're + + align:start position:0% +things about matrix mechanics is you're + + + align:start position:0% +things about matrix mechanics is you're +dealing with vectors and you're dealing + + align:start position:0% +dealing with vectors and you're dealing + + + align:start position:0% +dealing with vectors and you're dealing +you're not looking at the differential + + align:start position:0% +you're not looking at the differential + + + align:start position:0% +you're not looking at the differential +operators and you you get to do things + + align:start position:0% +operators and you you get to do things + + + align:start position:0% +operators and you you get to do things +that are terribly profound without doing + + align:start position:0% +that are terribly profound without doing + + + align:start position:0% +that are terribly profound without doing +very much work okay so we have 80 now we + + align:start position:0% +very much work okay so we have 80 now we + + + align:start position:0% +very much work okay so we have 80 now we +have the perturbation term and since + + align:start position:0% +have the perturbation term and since + + + align:start position:0% +have the perturbation term and since +we're dealing with an harmonic + + align:start position:0% +we're dealing with an harmonic + + + align:start position:0% +we're dealing with an harmonic +oscillators we'd like to be able to say + + align:start position:0% +oscillators we'd like to be able to say + + + align:start position:0% +oscillators we'd like to be able to say +something Universal about the coordinate + + align:start position:0% +something Universal about the coordinate + + + align:start position:0% +something Universal about the coordinate +displacement and the momentum which is + + align:start position:0% +displacement and the momentum which is + + + align:start position:0% +displacement and the momentum which is +conjugate and so + + align:start position:0% +conjugate and so + + + align:start position:0% +conjugate and so +it's a wonderful thing to replace a cool + + align:start position:0% +it's a wonderful thing to replace a cool + + + align:start position:0% +it's a wonderful thing to replace a cool +ordinate that depends on all sorts of + + align:start position:0% +ordinate that depends on all sorts of + + + align:start position:0% +ordinate that depends on all sorts of +things like what system of masses you're + + align:start position:0% +things like what system of masses you're + + + align:start position:0% +things like what system of masses you're +using and what what + + align:start position:0% +using and what what + + + align:start position:0% +using and what what +coordinates + + align:start position:0% +coordinates + + + align:start position:0% +coordinates +you're using to replace them by a + + align:start position:0% +you're using to replace them by a + + + align:start position:0% +you're using to replace them by a +dimensionless quantity so we have this + + align:start position:0% +dimensionless quantity so we have this + + + align:start position:0% +dimensionless quantity so we have this +scale factor 2 pi c mu + + align:start position:0% +scale factor 2 pi c mu + + + align:start position:0% +scale factor 2 pi c mu +0 maybeee right this + + align:start position:0% +0 maybeee right this + + + align:start position:0% +0 maybeee right this +is a dimensionless quantity and + + align:start position:0% +is a dimensionless quantity and + + + align:start position:0% +is a dimensionless quantity and +so that makes it universal and so if you + + align:start position:0% +so that makes it universal and so if you + + + align:start position:0% +so that makes it universal and so if you +not a strip out the specific molecule + + align:start position:0% +not a strip out the specific molecule + + + align:start position:0% +not a strip out the specific molecule +specific things the reduced mass and the + + align:start position:0% +specific things the reduced mass and the + + + align:start position:0% +specific things the reduced mass and the +fourth constants I guess know it's there + + align:start position:0% +fourth constants I guess know it's there + + + align:start position:0% +fourth constants I guess know it's there +okay if you strip out the molecule + + align:start position:0% +okay if you strip out the molecule + + + align:start position:0% +okay if you strip out the molecule +specific stuff then you're going to be + + align:start position:0% +specific stuff then you're going to be + + + align:start position:0% +specific stuff then you're going to be +dealing with universal things and you + + align:start position:0% +dealing with universal things and you + + + align:start position:0% +dealing with universal things and you +solve problems once and then you just + + align:start position:0% +solve problems once and then you just + + + align:start position:0% +solve problems once and then you just +know how to scale them okay + + align:start position:0% +know how to scale them okay + + + align:start position:0% +know how to scale them okay +and the same is true for P the factor + + align:start position:0% +and the same is true for P the factor + + + align:start position:0% +and the same is true for P the factor +here is you + + align:start position:0% +here is you + + + align:start position:0% +here is you +see I don't even I have to look at my + + align:start position:0% +see I don't even I have to look at my + + + align:start position:0% +see I don't even I have to look at my +notes because I don't know what the + + align:start position:0% +notes because I don't know what the + + + align:start position:0% +notes because I don't know what the +factor is but I only have to do it once + + align:start position:0% +factor is but I only have to do it once + + + align:start position:0% +factor is but I only have to do it once +dupuy + + align:start position:0% + + + + align:start position:0% + +c mu omega e spero + + align:start position:0% +c mu omega e spero + + + align:start position:0% +c mu omega e spero +p hat + + align:start position:0% + + + + align:start position:0% + +and then there's a further reduction q + + align:start position:0% +and then there's a further reduction q + + + align:start position:0% +and then there's a further reduction q +now + + align:start position:0% +now + + + align:start position:0% +now +if I tell you what are in the basis set + + align:start position:0% +if I tell you what are in the basis set + + + align:start position:0% +if I tell you what are in the basis set +of the harmonic oscillator where we have + + align:start position:0% +of the harmonic oscillator where we have + + + align:start position:0% +of the harmonic oscillator where we have +these kinds of functions v what are what + + align:start position:0% +these kinds of functions v what are what + + + align:start position:0% +these kinds of functions v what are what +is the selection rule for matrix + + align:start position:0% +is the selection rule for matrix + + + align:start position:0% +is the selection rule for matrix +elements of q most of you know that most + + align:start position:0% +elements of q most of you know that most + + + align:start position:0% +elements of q most of you know that most +of you know that from the Schrodinger + + align:start position:0% +of you know that from the Schrodinger + + + align:start position:0% +of you know that from the Schrodinger +picture from a first course in quantum + + align:start position:0% +picture from a first course in quantum + + + align:start position:0% +picture from a first course in quantum +mechanics you know that the coordinate + + align:start position:0% +mechanics you know that the coordinate + + + align:start position:0% +mechanics you know that the coordinate +changes the quantum number x plus or + + align:start position:0% +changes the quantum number x plus or + + + align:start position:0% +changes the quantum number x plus or +minus one okay + + align:start position:0% +minus one okay + + + align:start position:0% +minus one okay +and so the matrix elements of Q are + + align:start position:0% +and so the matrix elements of Q are + + + align:start position:0% +and so the matrix elements of Q are +going to be Delta V of plus and minus + + align:start position:0% +going to be Delta V of plus and minus + + + align:start position:0% +going to be Delta V of plus and minus +one and many + + align:start position:0% +one and many + + + align:start position:0% +one and many +of you also probably know what the + + align:start position:0% +of you also probably know what the + + + align:start position:0% +of you also probably know what the +actual value is but you don't really you + + align:start position:0% +actual value is but you don't really you + + + align:start position:0% +actual value is but you don't really you +know but you don't know how to dig it + + align:start position:0% +know but you don't know how to dig it + + + align:start position:0% +know but you don't know how to dig it +out because it's entangled with all this + + align:start position:0% +out because it's entangled with all this + + + align:start position:0% +out because it's entangled with all this +garbage and factor a square root of two + + align:start position:0% +garbage and factor a square root of two + + + align:start position:0% +garbage and factor a square root of two +and so it doesn't look memorable so if + + align:start position:0% +and so it doesn't look memorable so if + + + align:start position:0% +and so it doesn't look memorable so if +we replace this by 1 over square root of + + align:start position:0% +we replace this by 1 over square root of + + + align:start position:0% +we replace this by 1 over square root of +two times a plus a dagger + + align:start position:0% + + + + align:start position:0% + +then we now have simplified q in terms + + align:start position:0% +then we now have simplified q in terms + + + align:start position:0% +then we now have simplified q in terms +of operators which have two + + align:start position:0% +of operators which have two + + + align:start position:0% +of operators which have two +wonderfully convenient properties a + + align:start position:0% +wonderfully convenient properties a + + + align:start position:0% +wonderfully convenient properties a +decreases + + align:start position:0% + + + + align:start position:0% + +the number of quanta of the thing on its + + align:start position:0% +the number of quanta of the thing on its + + + align:start position:0% +the number of quanta of the thing on its +right by one a dagger increases the + + align:start position:0% +right by one a dagger increases the + + + align:start position:0% +right by one a dagger increases the +number of quanta of the thing that's + + align:start position:0% +number of quanta of the thing that's + + + align:start position:0% +number of quanta of the thing that's +right and it gives you a number they + + align:start position:0% +right and it gives you a number they + + + align:start position:0% +right and it gives you a number they +both give you a number and so if you + + align:start position:0% +both give you a number and so if you + + + align:start position:0% +both give you a number and so if you +write it this way a V + + align:start position:0% +write it this way a V + + + align:start position:0% +write it this way a V +plus 1 B you + + align:start position:0% +plus 1 B you + + + align:start position:0% +plus 1 B you +get D plus 1 square root and it's right + + align:start position:0% +get D plus 1 square root and it's right + + + align:start position:0% +get D plus 1 square root and it's right +be + + align:start position:0% +be + + + align:start position:0% +be +a dagger + + align:start position:0% +a dagger + + + align:start position:0% +a dagger +B minus 1 you get V so + + align:start position:0% +B minus 1 you get V so + + + align:start position:0% +B minus 1 you get V so +there's only one non zero matrix element + + align:start position:0% +there's only one non zero matrix element + + + align:start position:0% +there's only one non zero matrix element +at a and a dagger q + + align:start position:0% +at a and a dagger q + + + align:start position:0% +at a and a dagger q +has two non zero matrix elements because + + align:start position:0% +has two non zero matrix elements because + + + align:start position:0% +has two non zero matrix elements because +it's a sum of a and a dagger this + + align:start position:0% +it's a sum of a and a dagger this + + + align:start position:0% +it's a sum of a and a dagger this +is simpler and this is wonderful because + + align:start position:0% +is simpler and this is wonderful because + + + align:start position:0% +is simpler and this is wonderful because +suppose I tell you that I have some + + align:start position:0% +suppose I tell you that I have some + + + align:start position:0% +suppose I tell you that I have some +operator that's q1 q2 q3 squared + + align:start position:0% +operator that's q1 q2 q3 squared + + + align:start position:0% +operator that's q1 q2 q3 squared +and I ask you well what's the matrix + + align:start position:0% +and I ask you well what's the matrix + + + align:start position:0% +and I ask you well what's the matrix +element between this number of + + align:start position:0% +element between this number of + + + align:start position:0% +element between this number of +vibrational this combination of + + align:start position:0% +vibrational this combination of + + + align:start position:0% +vibrational this combination of +vibrational quantum / than that and as + + align:start position:0% +vibrational quantum / than that and as + + + align:start position:0% +vibrational quantum / than that and as +soon as I tell you that I you know + + align:start position:0% +soon as I tell you that I you know + + + align:start position:0% +soon as I tell you that I you know +exactly how many a's and a daggers to + + align:start position:0% +exactly how many a's and a daggers to + + + align:start position:0% +exactly how many a's and a daggers to +pull out and then you know exactly how + + align:start position:0% +pull out and then you know exactly how + + + align:start position:0% +pull out and then you know exactly how +to evaluate all the matrix elements so + + align:start position:0% +to evaluate all the matrix elements so + + + align:start position:0% +to evaluate all the matrix elements so +this simple thing is saying whether it's + + align:start position:0% +this simple thing is saying whether it's + + + align:start position:0% +this simple thing is saying whether it's +a or a dagger doesn't + + align:start position:0% +a or a dagger doesn't + + + align:start position:0% +a or a dagger doesn't +matter you just take the larger of the + + align:start position:0% +matter you just take the larger of the + + + align:start position:0% +matter you just take the larger of the +two quantum numbers and take the square + + align:start position:0% +two quantum numbers and take the square + + + align:start position:0% +two quantum numbers and take the square +root that's + + align:start position:0% +root that's + + + align:start position:0% +root that's +all you ever have to remember for + + align:start position:0% +all you ever have to remember for + + + align:start position:0% +all you ever have to remember for +harmonic oscillator matrix elements the + + align:start position:0% +harmonic oscillator matrix elements the + + + align:start position:0% +harmonic oscillator matrix elements the +larger of the two and you you also + + align:start position:0% +larger of the two and you you also + + + align:start position:0% +larger of the two and you you also +recognize + + align:start position:0% + + + + align:start position:0% + +missing the plus and that's decreasing + + align:start position:0% +missing the plus and that's decreasing + + + align:start position:0% +missing the plus and that's decreasing +and that's all there is and so you can + + align:start position:0% +and that's all there is and so you can + + + align:start position:0% +and that's all there is and so you can +remember then all the matrix elements of + + align:start position:0% +remember then all the matrix elements of + + + align:start position:0% +remember then all the matrix elements of +Q and P and integer power of Q and P and + + align:start position:0% +Q and P and integer power of Q and P and + + + align:start position:0% +Q and P and integer power of Q and P and +if you're clever any non integer power + + align:start position:0% +if you're clever any non integer power + + + align:start position:0% +if you're clever any non integer power +of cumin p that's later okay + + align:start position:0% + + + + align:start position:0% + +so absolutely + + align:start position:0% + + + + align:start position:0% + +it's + + align:start position:0% +it's + + + align:start position:0% +it's +wrong on the lecture notes holy mackerel + + align:start position:0% +wrong on the lecture notes holy mackerel + + + align:start position:0% +wrong on the lecture notes holy mackerel +what's mine well it's factor too in + + align:start position:0% +what's mine well it's factor too in + + + align:start position:0% +what's mine well it's factor too in +this case okay well sorry about that I I + + align:start position:0% +this case okay well sorry about that I I + + + align:start position:0% +this case okay well sorry about that I I +don't know what I say I don't know what + + align:start position:0% +don't know what I say I don't know what + + + align:start position:0% +don't know what I say I don't know what +I right I don't know what's in my notes + + align:start position:0% +I right I don't know what's in my notes + + + align:start position:0% +I right I don't know what's in my notes +I mean there's the you know and two out + + align:start position:0% +I mean there's the you know and two out + + + align:start position:0% +I mean there's the you know and two out +of three is not good enough oh ok well + + align:start position:0% +of three is not good enough oh ok well + + + align:start position:0% +of three is not good enough oh ok well +that's okay well that's good alright so + + align:start position:0% +that's okay well that's good alright so + + + align:start position:0% +that's okay well that's good alright so +now + + align:start position:0% + + + + align:start position:0% + +there are some other things and last + + align:start position:0% +there are some other things and last + + + align:start position:0% +there are some other things and last +time when I went through the beginning + + align:start position:0% +time when I went through the beginning + + + align:start position:0% +time when I went through the beginning +of this I decided not to introduce these + + align:start position:0% +of this I decided not to introduce these + + + align:start position:0% +of this I decided not to introduce these +other simplifying factors but it turns + + align:start position:0% +other simplifying factors but it turns + + + align:start position:0% +other simplifying factors but it turns +out you really want them so we have a + + align:start position:0% +out you really want them so we have a + + + align:start position:0% +out you really want them so we have a +couple of other ways in which you deal + + align:start position:0% +couple of other ways in which you deal + + + align:start position:0% +couple of other ways in which you deal +with strings of A's and a daggers and + + align:start position:0% +with strings of A's and a daggers and + + + align:start position:0% +with strings of A's and a daggers and +one is the number operator which is a + + align:start position:0% +one is the number operator which is a + + + align:start position:0% +one is the number operator which is a +dagger a we + + align:start position:0% + + + + align:start position:0% + +want something which will return the + + align:start position:0% +want something which will return the + + + align:start position:0% +want something which will return the +number of quanta so if we write n on V + + align:start position:0% +number of quanta so if we write n on V + + + align:start position:0% +number of quanta so if we write n on V +we want V B and + + align:start position:0% +we want V B and + + + align:start position:0% +we want V B and +C a lowers + + align:start position:0% +C a lowers + + + align:start position:0% +C a lowers +V a dagger raises it so if we have an + + align:start position:0% +V a dagger raises it so if we have an + + + align:start position:0% +V a dagger raises it so if we have an +equal number of A's and a daggers the + + align:start position:0% +equal number of A's and a daggers the + + + align:start position:0% +equal number of A's and a daggers the +matrix element in question is diagonal + + align:start position:0% +matrix element in question is diagonal + + + align:start position:0% +matrix element in question is diagonal +and V so + + align:start position:0% +and V so + + + align:start position:0% +and V so +but now you look at this and you say + + align:start position:0% +but now you look at this and you say + + + align:start position:0% +but now you look at this and you say +well i'm going to apply this to the V + + align:start position:0% +well i'm going to apply this to the V + + + align:start position:0% +well i'm going to apply this to the V +state and I'm going to decrease p by one + + align:start position:0% +state and I'm going to decrease p by one + + + align:start position:0% +state and I'm going to decrease p by one +but the larger of the two quantum + + align:start position:0% +but the larger of the two quantum + + + align:start position:0% +but the larger of the two quantum +numbers is where you start it's that's + + align:start position:0% +numbers is where you start it's that's + + + align:start position:0% +numbers is where you start it's that's +square root of V and I'm going to III + + align:start position:0% +square root of V and I'm going to III + + + align:start position:0% +square root of V and I'm going to III +increase it again back to V and so we + + align:start position:0% +increase it again back to V and so we + + + align:start position:0% +increase it again back to V and so we +get a factor of square root square root + + align:start position:0% +get a factor of square root square root + + + align:start position:0% +get a factor of square root square root +of V from both of these and that's what + + align:start position:0% +of V from both of these and that's what + + + align:start position:0% +of V from both of these and that's what +we get this so that's the number + + align:start position:0% +we get this so that's the number + + + align:start position:0% +we get this so that's the number +operator and that's convenient and then + + align:start position:0% +operator and that's convenient and then + + + align:start position:0% +operator and that's convenient and then +we have some commutation rules + + align:start position:0% +we have some commutation rules + + + align:start position:0% +we have some commutation rules +and so + + align:start position:0% +and so + + + align:start position:0% +and so +that's just a dagger a minus + + align:start position:0% +that's just a dagger a minus + + + align:start position:0% +that's just a dagger a minus +a dagger and so + + align:start position:0% +a dagger and so + + + align:start position:0% +a dagger and so +you can figure out what that is by + + align:start position:0% +you can figure out what that is by + + + align:start position:0% +you can figure out what that is by +applying this to V but + + align:start position:0% +applying this to V but + + + align:start position:0% +applying this to V but +i'm + + align:start position:0% + + + + align:start position:0% + +just going to tell you it's minus 1 and + + align:start position:0% +just going to tell you it's minus 1 and + + + align:start position:0% +just going to tell you it's minus 1 and +if you do it the other order a a dagger + + align:start position:0% +if you do it the other order a a dagger + + + align:start position:0% +if you do it the other order a a dagger +its plus 1 and then there is commutation + + align:start position:0% +its plus 1 and then there is commutation + + + align:start position:0% +its plus 1 and then there is commutation +rules involving m and a dagger this + + align:start position:0% +rules involving m and a dagger this + + + align:start position:0% +rules involving m and a dagger this +is quantum mechanics so you have to + + align:start position:0% +is quantum mechanics so you have to + + + align:start position:0% +is quantum mechanics so you have to +watch out the order in which things + + align:start position:0% +watch out the order in which things + + + align:start position:0% +watch out the order in which things +appear and one + + align:start position:0% +appear and one + + + align:start position:0% +appear and one +of the beautiful things when you have n + + align:start position:0% +of the beautiful things when you have n + + + align:start position:0% +of the beautiful things when you have n +with a dagger is you just get a dagger + + align:start position:0% +with a dagger is you just get a dagger + + + align:start position:0% +with a dagger is you just get a dagger +back when you have n with a you just get + + align:start position:0% +back when you have n with a you just get + + + align:start position:0% +back when you have n with a you just get +a back but it's a minus sign + + align:start position:0% + + + + align:start position:0% + +so these little tricks enable you to + + align:start position:0% +so these little tricks enable you to + + + align:start position:0% +so these little tricks enable you to +make tremendous simplifications and so + + align:start position:0% +make tremendous simplifications and so + + + align:start position:0% +make tremendous simplifications and so +now let's look at Q squared well Q + + align:start position:0% +now let's look at Q squared well Q + + + align:start position:0% +now let's look at Q squared well Q +squared is one-half a plus a dagger + + align:start position:0% +squared is one-half a plus a dagger + + + align:start position:0% +squared is one-half a plus a dagger +square + + align:start position:0% +square + + + align:start position:0% +square +and so we immediately know we got a + + align:start position:0% +and so we immediately know we got a + + + align:start position:0% +and so we immediately know we got a +squared a dagger squared and then we get + + align:start position:0% +squared a dagger squared and then we get + + + align:start position:0% +squared a dagger squared and then we get +a a dagger plus a dagger a so + + align:start position:0% +a a dagger plus a dagger a so + + + align:start position:0% +a a dagger plus a dagger a so +that's the number operator and this is + + align:start position:0% +that's the number operator and this is + + + align:start position:0% +that's the number operator and this is +the number operator written in the wrong + + align:start position:0% +the number operator written in the wrong + + + align:start position:0% +the number operator written in the wrong +order until you can you can permute + + align:start position:0% +order until you can you can permute + + + align:start position:0% +order until you can you can permute +these so suppose you have a a dagger you + + align:start position:0% +these so suppose you have a a dagger you + + + align:start position:0% +these so suppose you have a a dagger you +can write that as a a dagger plus + + align:start position:0% +can write that as a a dagger plus + + + align:start position:0% +can write that as a a dagger plus +a dagger a minus a dagger a and then you + + align:start position:0% +a dagger a minus a dagger a and then you + + + align:start position:0% +a dagger a minus a dagger a and then you +combine these two terms and those two + + align:start position:0% +combine these two terms and those two + + + align:start position:0% +combine these two terms and those two +terms are the commutator a a dagger and + + align:start position:0% +terms are the commutator a a dagger and + + + align:start position:0% +terms are the commutator a a dagger and +the + + align:start position:0% +the + + + align:start position:0% +the +commutator a a dagger is one so + + align:start position:0% +commutator a a dagger is one so + + + align:start position:0% +commutator a a dagger is one so +we take these two terms combined them + + align:start position:0% +we take these two terms combined them + + + align:start position:0% +we take these two terms combined them +they're just one and this is the number + + align:start position:0% +they're just one and this is the number + + + align:start position:0% +they're just one and this is the number +operator and so + + align:start position:0% +operator and so + + + align:start position:0% +operator and so +to + + align:start position:0% +to + + + align:start position:0% +to +to take a term which is written not in + + align:start position:0% +to take a term which is written not in + + + align:start position:0% +to take a term which is written not in +the order of the number operator and + + align:start position:0% +the order of the number operator and + + + align:start position:0% +the order of the number operator and +reduce it to the number operator you ask + + align:start position:0% +reduce it to the number operator you ask + + + align:start position:0% +reduce it to the number operator you ask +how many times do I have to permute in a + + align:start position:0% +how many times do I have to permute in a + + + align:start position:0% +how many times do I have to permute in a +dagger plastic past a and so + + align:start position:0% +dagger plastic past a and so + + + align:start position:0% +dagger plastic past a and so +each time you have a term like a a + + align:start position:0% +each time you have a term like a a + + + align:start position:0% +each time you have a term like a a +dagger or a dagger a you're going to get + + align:start position:0% +dagger or a dagger a you're going to get + + + align:start position:0% +dagger or a dagger a you're going to get +a number operator but you're going to + + align:start position:0% +a number operator but you're going to + + + align:start position:0% +a number operator but you're going to +get something extra from this one + + align:start position:0% +get something extra from this one + + + align:start position:0% +get something extra from this one +because you had up in route / mute okay + + align:start position:0% +because you had up in route / mute okay + + + align:start position:0% +because you had up in route / mute okay +and so it + + align:start position:0% +and so it + + + align:start position:0% +and so it +turns out you can very quickly look at + + align:start position:0% +turns out you can very quickly look at + + + align:start position:0% +turns out you can very quickly look at +these sorts of things and write down + + align:start position:0% +these sorts of things and write down + + + align:start position:0% +these sorts of things and write down +what + + align:start position:0% +what + + + align:start position:0% +what +they are in terms of the most compact + + align:start position:0% +they are in terms of the most compact + + + align:start position:0% +they are in terms of the most compact +form and so we + + align:start position:0% +form and so we + + + align:start position:0% +form and so we +get one + + align:start position:0% +get one + + + align:start position:0% +get one +half a squared + + align:start position:0% + + + + align:start position:0% + +a dagger squared plus 2n plus one so + + align:start position:0% +a dagger squared plus 2n plus one so + + + align:start position:0% +a dagger squared plus 2n plus one so +this is this is the number operator it's + + align:start position:0% +this is this is the number operator it's + + + align:start position:0% +this is this is the number operator it's +not a constant if you multiply it on v + + align:start position:0% +not a constant if you multiply it on v + + + align:start position:0% +not a constant if you multiply it on v +plus one you get v plus 1 not be okay + + align:start position:0% +plus one you get v plus 1 not be okay + + + align:start position:0% +plus one you get v plus 1 not be okay +so this is how you reduce a Q squared + + align:start position:0% +so this is how you reduce a Q squared + + + align:start position:0% +so this is how you reduce a Q squared +you + + align:start position:0% +you + + + align:start position:0% +you +can reduce p squared similarly + + align:start position:0% +can reduce p squared similarly + + + align:start position:0% +can reduce p squared similarly +I'm not going to do it it's in the notes + + align:start position:0% +I'm not going to do it it's in the notes + + + align:start position:0% +I'm not going to do it it's in the notes +when + + align:start position:0% +when + + + align:start position:0% +when +you do Q squared plus B squared you + + align:start position:0% +you do Q squared plus B squared you + + + align:start position:0% +you do Q squared plus B squared you +discover from the definition of P which + + align:start position:0% +discover from the definition of P which + + + align:start position:0% +discover from the definition of P which +I didn't write down today which has a + + align:start position:0% +I didn't write down today which has a + + + align:start position:0% +I didn't write down today which has a +minus we have a dagger minus a but + + align:start position:0% +minus we have a dagger minus a but + + + align:start position:0% +minus we have a dagger minus a but +there's a I in front you end up having + + align:start position:0% +there's a I in front you end up having + + + align:start position:0% +there's a I in front you end up having +these raising + + align:start position:0% +these raising + + + align:start position:0% +these raising +and lowering operators squared cancel + + align:start position:0% +and lowering operators squared cancel + + + align:start position:0% +and lowering operators squared cancel +giving + + align:start position:0% +giving + + + align:start position:0% +giving +back giving you 2 n plus 1 times a half + + align:start position:0% +back giving you 2 n plus 1 times a half + + + align:start position:0% +back giving you 2 n plus 1 times a half +from from + + align:start position:0% +from from + + + align:start position:0% +from from +each and the overall matrix element if a + + align:start position:0% +each and the overall matrix element if a + + + align:start position:0% +each and the overall matrix element if a +0 comes out to be just n plus a half + + align:start position:0% +0 comes out to be just n plus a half + + + align:start position:0% +0 comes out to be just n plus a half +it's + + align:start position:0% +it's + + + align:start position:0% +it's +you + + align:start position:0% +you + + + align:start position:0% +you +have 2n plus 1 1 + + align:start position:0% +have 2n plus 1 1 + + + align:start position:0% +have 2n plus 1 1 +half Omega E is what you get by adding + + align:start position:0% +half Omega E is what you get by adding + + + align:start position:0% +half Omega E is what you get by adding +the the one half P squared plus one-half + + align:start position:0% +the the one half P squared plus one-half + + + align:start position:0% +the the one half P squared plus one-half +Q squared stuff so so that you + + align:start position:0% +Q squared stuff so so that you + + + align:start position:0% +Q squared stuff so so that you +you discover the Q squared is not + + align:start position:0% +you discover the Q squared is not + + + align:start position:0% +you discover the Q squared is not +diagonal p squared is not diagonal but + + align:start position:0% +diagonal p squared is not diagonal but + + + align:start position:0% +diagonal p squared is not diagonal but +their sum is that's + + align:start position:0% +their sum is that's + + + align:start position:0% +their sum is that's +good you want it to be diagonal because + + align:start position:0% +good you want it to be diagonal because + + + align:start position:0% +good you want it to be diagonal because +you wanted those to be eigenfunctions of + + align:start position:0% +you wanted those to be eigenfunctions of + + + align:start position:0% +you wanted those to be eigenfunctions of +you + + align:start position:0% +you + + + align:start position:0% +you +wanted to have harmonic oscillator + + align:start position:0% +wanted to have harmonic oscillator + + + align:start position:0% +wanted to have harmonic oscillator +eigenfunctions okay so now the next + + align:start position:0% +eigenfunctions okay so now the next + + + align:start position:0% +eigenfunctions okay so now the next +blackboard do over here suppose + + align:start position:0% + + + + align:start position:0% + +we want Q to + + align:start position:0% +we want Q to + + + align:start position:0% +we want Q to +the third power well + + align:start position:0% +the third power well + + + align:start position:0% +the third power well +we know when we left the Hat we know + + align:start position:0% +we know when we left the Hat we know + + + align:start position:0% +we know when we left the Hat we know +that we're going to have 1 over square + + align:start position:0% +that we're going to have 1 over square + + + align:start position:0% +that we're going to have 1 over square +root of two three times so it's to the + + align:start position:0% +root of two three times so it's to the + + + align:start position:0% +root of two three times so it's to the +minus three halves and we know we're + + align:start position:0% +minus three halves and we know we're + + + align:start position:0% +minus three halves and we know we're +going to have a dagger cubed and we know + + align:start position:0% +going to have a dagger cubed and we know + + + align:start position:0% +going to have a dagger cubed and we know +we're going to have a a cube and then we + + align:start position:0% +we're going to have a a cube and then we + + + align:start position:0% +we're going to have a a cube and then we +know we're going to have three terms + + align:start position:0% +know we're going to have three terms + + + align:start position:0% +know we're going to have three terms +that have a a dagger a in + + align:start position:0% +that have a a dagger a in + + + align:start position:0% +that have a a dagger a in +the various orders and we're going to + + align:start position:0% +the various orders and we're going to + + + align:start position:0% +the various orders and we're going to +have three terms involving a a a dagger + + align:start position:0% +have three terms involving a a a dagger + + + align:start position:0% +have three terms involving a a a dagger +and + + align:start position:0% +and + + + align:start position:0% +and +so that the trick before one gets into + + align:start position:0% +so that the trick before one gets into + + + align:start position:0% +so that the trick before one gets into +heavy duty perturbation theory is to + + align:start position:0% +heavy duty perturbation theory is to + + + align:start position:0% +heavy duty perturbation theory is to +simplify these things and so because + + align:start position:0% +simplify these things and so because + + + align:start position:0% +simplify these things and so because +there's three terms we know we're going + + align:start position:0% +there's three terms we know we're going + + + align:start position:0% +there's three terms we know we're going +to get three times some simple thing a + + align:start position:0% +to get three times some simple thing a + + + align:start position:0% +to get three times some simple thing a +number operate well first of all a + + align:start position:0% +number operate well first of all a + + + align:start position:0% +number operate well first of all a +dagger we've got to a daggers in 1a so + + align:start position:0% +dagger we've got to a daggers in 1a so + + + align:start position:0% +dagger we've got to a daggers in 1a so +the overall thing is going to change + + align:start position:0% +the overall thing is going to change + + + align:start position:0% +the overall thing is going to change +increase v by one so it's going to look + + align:start position:0% +increase v by one so it's going to look + + + align:start position:0% +increase v by one so it's going to look +something like n a dagger so let's + + align:start position:0% +something like n a dagger so let's + + + align:start position:0% +something like n a dagger so let's +extract from these three terms three + + align:start position:0% +extract from these three terms three + + + align:start position:0% +extract from these three terms three +times a diagram and + + align:start position:0% +times a diagram and + + + align:start position:0% +times a diagram and +so + + align:start position:0% + + + + align:start position:0% + +what + + align:start position:0% +what + + + align:start position:0% +what +does that look like a dagger n looks + + align:start position:0% +does that look like a dagger n looks + + + align:start position:0% +does that look like a dagger n looks +like that + + align:start position:0% +like that + + + align:start position:0% +like that +so that's one of the three terms we have + + align:start position:0% +so that's one of the three terms we have + + + align:start position:0% +so that's one of the three terms we have +a dagger a a dagger and we have a a + + align:start position:0% +a dagger a a dagger and we have a a + + + align:start position:0% +a dagger a a dagger and we have a a +dagger a dagger okay + + align:start position:0% +dagger a dagger okay + + + align:start position:0% +dagger a dagger okay +so this is right this one we have to + + align:start position:0% +so this is right this one we have to + + + align:start position:0% +so this is right this one we have to +permute the a past the a dagger so + + align:start position:0% +permute the a past the a dagger so + + + align:start position:0% +permute the a past the a dagger so +we have to do one permutation this + + align:start position:0% +we have to do one permutation this + + + align:start position:0% +we have to do one permutation this +one we have to do one permutation than + + align:start position:0% +one we have to do one permutation than + + + align:start position:0% +one we have to do one permutation than +one more so + + align:start position:0% +one more so + + + align:start position:0% +one more so +when you do that you discover that + + align:start position:0% + + + + align:start position:0% + +we get three + + align:start position:0% +we get three + + + align:start position:0% +we get three +times a dagger + + align:start position:0% +times a dagger + + + align:start position:0% +times a dagger +n plus + + align:start position:0% +n plus + + + align:start position:0% +n plus +1 or we get 3 a daggers and three a + + align:start position:0% +1 or we get 3 a daggers and three a + + + align:start position:0% +1 or we get 3 a daggers and three a +dagger ends notice + + align:start position:0% +dagger ends notice + + + align:start position:0% +dagger ends notice +that all of these terms change the + + align:start position:0% +that all of these terms change the + + + align:start position:0% +that all of these terms change the +vibrational quantum number up by one so + + align:start position:0% +vibrational quantum number up by one so + + + align:start position:0% +vibrational quantum number up by one so +there's a beauty to this algebra because + + align:start position:0% +there's a beauty to this algebra because + + + align:start position:0% +there's a beauty to this algebra because +you know what you're going to get you + + align:start position:0% +you know what you're going to get you + + + align:start position:0% +you know what you're going to get you +have to do a little work to massage the + + align:start position:0% +have to do a little work to massage the + + + align:start position:0% +have to do a little work to massage the +terms to all come out you know in this + + align:start position:0% +terms to all come out you know in this + + + align:start position:0% +terms to all come out you know in this +form but and you know you're going to + + align:start position:0% +form but and you know you're going to + + + align:start position:0% +form but and you know you're going to +have a term that changes the vibrational + + align:start position:0% +have a term that changes the vibrational + + + align:start position:0% +have a term that changes the vibrational +quantum number by one or in this from + + align:start position:0% +quantum number by one or in this from + + + align:start position:0% +quantum number by one or in this from +this you're going to have a term that + + align:start position:0% +this you're going to have a term that + + + align:start position:0% +this you're going to have a term that +decreases the vibrational quantum number + + align:start position:0% +decreases the vibrational quantum number + + + align:start position:0% +decreases the vibrational quantum number +by one and so these three terms are + + align:start position:0% +by one and so these three terms are + + + align:start position:0% +by one and so these three terms are +going to give you in just three a n and + + align:start position:0% +going to give you in just three a n and + + + align:start position:0% +going to give you in just three a n and +so you should go through this because + + align:start position:0% +so you should go through this because + + + align:start position:0% +so you should go through this because +you can fill sheets of paper doing the + + align:start position:0% +you can fill sheets of paper doing the + + + align:start position:0% +you can fill sheets of paper doing the +algebra subtracting + + align:start position:0% +algebra subtracting + + + align:start position:0% +algebra subtracting +and adding terms or you can just say oh + + align:start position:0% +and adding terms or you can just say oh + + + align:start position:0% +and adding terms or you can just say oh +yeah I want to rearrange the order by + + align:start position:0% +yeah I want to rearrange the order by + + + align:start position:0% +yeah I want to rearrange the order by +doing a series of binary binary + + align:start position:0% +doing a series of binary binary + + + align:start position:0% +doing a series of binary binary +permutations and once + + align:start position:0% +permutations and once + + + align:start position:0% +permutations and once +you've got the hang of that then you + + align:start position:0% +you've got the hang of that then you + + + align:start position:0% +you've got the hang of that then you +just count the number of binary + + align:start position:0% +just count the number of binary + + + align:start position:0% +just count the number of binary +permutations and you multiply the the + + align:start position:0% +permutations and you multiply the the + + + align:start position:0% +permutations and you multiply the the +orphan + + align:start position:0% +orphan + + + align:start position:0% +orphan +term and you've got it and so similarly + + align:start position:0% +term and you've got it and so similarly + + + align:start position:0% +term and you've got it and so similarly +for q4 for q4 one has 14 times a diagram + + align:start position:0% +for q4 for q4 one has 14 times a diagram + + + align:start position:0% +for q4 for q4 one has 14 times a diagram +the fourth a the fourth and then we're + + align:start position:0% +the fourth a the fourth and then we're + + + align:start position:0% +the fourth a the fourth and then we're +going to have one term that has one more + + align:start position:0% +going to have one term that has one more + + + align:start position:0% +going to have one term that has one more +dagger than not and + + align:start position:0% +dagger than not and + + + align:start position:0% +dagger than not and +what one term that has I'm + + align:start position:0% +what one term that has I'm + + + align:start position:0% +what one term that has I'm +sorry we're going to have a dagger a + + align:start position:0% +sorry we're going to have a dagger a + + + align:start position:0% +sorry we're going to have a dagger a +dagger a dagger a 2 more daggers than + + align:start position:0% +dagger a dagger a 2 more daggers than + + + align:start position:0% +dagger a dagger a 2 more daggers than +not and we're going to have one term + + align:start position:0% +not and we're going to have one term + + + align:start position:0% +not and we're going to have one term +that's a a + + align:start position:0% +that's a a + + + align:start position:0% +that's a a +a dagger and we'll have other terms that + + align:start position:0% +a dagger and we'll have other terms that + + + align:start position:0% +a dagger and we'll have other terms that +have this combination so these are going + + align:start position:0% +have this combination so these are going + + + align:start position:0% +have this combination so these are going +to change the vibrational quantum number + + align:start position:0% +to change the vibrational quantum number + + + align:start position:0% +to change the vibrational quantum number +by to increase it by two these are going + + align:start position:0% +by to increase it by two these are going + + + align:start position:0% +by to increase it by two these are going +to decrease it by two and these are not + + align:start position:0% +to decrease it by two and these are not + + + align:start position:0% +to decrease it by two and these are not +going to change it we already know from + + align:start position:0% +going to change it we already know from + + + align:start position:0% +going to change it we already know from +what you know from however you saw + + align:start position:0% +what you know from however you saw + + + align:start position:0% +what you know from however you saw +matrix elements of Q in your previous + + align:start position:0% +matrix elements of Q in your previous + + + align:start position:0% +matrix elements of Q in your previous +life you know that there's going to be + + align:start position:0% +life you know that there's going to be + + + align:start position:0% +life you know that there's going to be +Delta V of for delta v of 2 delta v of 0 + + align:start position:0% +Delta V of for delta v of 2 delta v of 0 + + + align:start position:0% +Delta V of for delta v of 2 delta v of 0 +delta v of minus 2 delta v of minus 4 + + align:start position:0% +delta v of minus 2 delta v of minus 4 + + + align:start position:0% +delta v of minus 2 delta v of minus 4 +and it's nice to be able to get them + + align:start position:0% +and it's nice to be able to get them + + + align:start position:0% +and it's nice to be able to get them +without having to do an awful lot of + + align:start position:0% +without having to do an awful lot of + + + align:start position:0% +without having to do an awful lot of +work now + + align:start position:0% +work now + + + align:start position:0% +work now +you can also have a computer set up the + + align:start position:0% +you can also have a computer set up the + + + align:start position:0% +you can also have a computer set up the +matrix for Q and then + + align:start position:0% +matrix for Q and then + + + align:start position:0% +matrix for Q and then +do matrix multiplication of those things + + align:start position:0% +do matrix multiplication of those things + + + align:start position:0% +do matrix multiplication of those things +and that's easy to instruct a computer + + align:start position:0% +and that's easy to instruct a computer + + + align:start position:0% +and that's easy to instruct a computer +to do too but this is nice because you + + align:start position:0% +to do too but this is nice because you + + + align:start position:0% +to do too but this is nice because you +you actually arrange things and you + + align:start position:0% +you actually arrange things and you + + + align:start position:0% +you actually arrange things and you +discover how to put things together + + align:start position:0% +discover how to put things together + + + align:start position:0% +discover how to put things together +without doing a lot of work okay + + align:start position:0% +without doing a lot of work okay + + + align:start position:0% +without doing a lot of work okay +so with + + align:start position:0% +so with + + + align:start position:0% +so with +this algebra you're really in a position + + align:start position:0% +this algebra you're really in a position + + + align:start position:0% +this algebra you're really in a position +now to write down all of the necessary + + align:start position:0% +now to write down all of the necessary + + + align:start position:0% +now to write down all of the necessary +perturbation + + align:start position:0% +perturbation + + + align:start position:0% +perturbation +theory to solve the problem and in + + align:start position:0% +theory to solve the problem and in + + + align:start position:0% +theory to solve the problem and in +addition you've got to hand out with + + align:start position:0% +addition you've got to hand out with + + + align:start position:0% +addition you've got to hand out with +this lecture which actually does it so + + align:start position:0% +this lecture which actually does it so + + + align:start position:0% +this lecture which actually does it so +there's not too much trouble actually + + align:start position:0% +there's not too much trouble actually + + + align:start position:0% +there's not too much trouble actually +doing this problem but i think you know + + align:start position:0% +doing this problem but i think you know + + + align:start position:0% +doing this problem but i think you know +you really want to go through the paces + + align:start position:0% +you really want to go through the paces + + + align:start position:0% +you really want to go through the paces +using this stuff okay so now I you + + align:start position:0% + + + + align:start position:0% + +know I don't think many of you are + + align:start position:0% +know I don't think many of you are + + + align:start position:0% +know I don't think many of you are +interested in making a career doing + + align:start position:0% +interested in making a career doing + + + align:start position:0% +interested in making a career doing +spectroscopy on diatomic molecules but + + align:start position:0% +spectroscopy on diatomic molecules but + + + align:start position:0% +spectroscopy on diatomic molecules but +one of the nice things about diatomic + + align:start position:0% +one of the nice things about diatomic + + + align:start position:0% +one of the nice things about diatomic +molecules is everything + + align:start position:0% +molecules is everything + + + align:start position:0% +molecules is everything +we can almost + + align:start position:0% + + + + align:start position:0% + +everything we can do for diatomic + + align:start position:0% +everything we can do for diatomic + + + align:start position:0% +everything we can do for diatomic +molecules we can do for polyatomic + + align:start position:0% +molecules we can do for polyatomic + + + align:start position:0% +molecules we can do for polyatomic +molecules and the things we can't do for + + align:start position:0% +molecules and the things we can't do for + + + align:start position:0% +molecules and the things we can't do for +polyatomic molecules like get a + + align:start position:0% +polyatomic molecules like get a + + + align:start position:0% +polyatomic molecules like get a +potential energy curve by the rid + + align:start position:0% +potential energy curve by the rid + + + align:start position:0% +potential energy curve by the rid +berkline Reese method which + + align:start position:0% +berkline Reese method which + + + align:start position:0% +berkline Reese method which +you can do for diatomics well you can't + + align:start position:0% +you can do for diatomics well you can't + + + align:start position:0% +you can do for diatomics well you can't +do that for polyatomic so you have to + + align:start position:0% +do that for polyatomic so you have to + + + align:start position:0% +do that for polyatomic so you have to +take something from diatomics and extend + + align:start position:0% +take something from diatomics and extend + + + align:start position:0% +take something from diatomics and extend +so suppose we have this triatomic + + align:start position:0% + + + + align:start position:0% + +molecule a bet triatomic molecule and + + align:start position:0% +molecule a bet triatomic molecule and + + + align:start position:0% +molecule a bet triatomic molecule and +we + + align:start position:0% +we + + + align:start position:0% +we +know that it belongs to the c2v point + + align:start position:0% +know that it belongs to the c2v point + + + align:start position:0% +know that it belongs to the c2v point +group the point group has four + + align:start position:0% +group the point group has four + + + align:start position:0% +group the point group has four +irreducible representations and + + align:start position:0% + + + + align:start position:0% + +we + + align:start position:0% +we + + + align:start position:0% +we +it's a try atomic you don't really need + + align:start position:0% +it's a try atomic you don't really need + + + align:start position:0% +it's a try atomic you don't really need +fancy techniques there's going to be a + + align:start position:0% +fancy techniques there's going to be a + + + align:start position:0% +fancy techniques there's going to be a +symmetric stretch is going to be a band + + align:start position:0% +symmetric stretch is going to be a band + + + align:start position:0% +symmetric stretch is going to be a band +and there's going to be an + + align:start position:0% +and there's going to be an + + + align:start position:0% +and there's going to be an +anti-symmetric stretch so we have the + + align:start position:0% +anti-symmetric stretch so we have the + + + align:start position:0% +anti-symmetric stretch so we have the +symmetric stretch that's + + align:start position:0% + + + + align:start position:0% + +new one and LBA one and we have a bend + + align:start position:0% +new one and LBA one and we have a bend + + + align:start position:0% +new one and LBA one and we have a bend +and that + + align:start position:0% +and that + + + align:start position:0% +and that +will be called new two and then + + align:start position:0% +will be called new two and then + + + align:start position:0% +will be called new two and then +we have and + + align:start position:0% +we have and + + + align:start position:0% +we have and +that's a one also and then we have the + + align:start position:0% +that's a one also and then we have the + + + align:start position:0% +that's a one also and then we have the +anti-symmetric stretch and that's be one + + align:start position:0% +anti-symmetric stretch and that's be one + + + align:start position:0% +anti-symmetric stretch and that's be one +that's + + align:start position:0% +that's + + + align:start position:0% +that's +next week okay + + align:start position:0% +next week okay + + + align:start position:0% +next week okay +so if you don't know group theory you + + align:start position:0% +so if you don't know group theory you + + + align:start position:0% +so if you don't know group theory you +will you will learn it but the important + + align:start position:0% +will you will learn it but the important + + + align:start position:0% +will you will learn it but the important +thing is this is called the totally + + align:start position:0% +thing is this is called the totally + + + align:start position:0% +thing is this is called the totally +symmetric representation the hamiltonian + + align:start position:0% +symmetric representation the hamiltonian + + + align:start position:0% +symmetric representation the hamiltonian +is totally symmetric if a hamiltonian is + + align:start position:0% +is totally symmetric if a hamiltonian is + + + align:start position:0% +is totally symmetric if a hamiltonian is +three a product of three things we + + align:start position:0% +three a product of three things we + + + align:start position:0% +three a product of three things we +function operator wave function and + + align:start position:0% +function operator wave function and + + + align:start position:0% +function operator wave function and +the + + align:start position:0% +the + + + align:start position:0% +the +operator in the hamiltonian has to + + align:start position:0% +operator in the hamiltonian has to + + + align:start position:0% +operator in the hamiltonian has to +belong to let + + align:start position:0% +belong to let + + + align:start position:0% +belong to let +me back up + + align:start position:0% + + + + align:start position:0% + +the + + align:start position:0% +the + + + align:start position:0% +the +hamiltonian itself belongs to the + + align:start position:0% +hamiltonian itself belongs to the + + + align:start position:0% +hamiltonian itself belongs to the +totally symmetric representation one + + align:start position:0% +totally symmetric representation one + + + align:start position:0% +totally symmetric representation one +can have off diagonal matrix elements of + + align:start position:0% +can have off diagonal matrix elements of + + + align:start position:0% +can have off diagonal matrix elements of +the hamiltonian but those are terms in + + align:start position:0% +the hamiltonian but those are terms in + + + align:start position:0% +the hamiltonian but those are terms in +the hamiltonian which combined + + align:start position:0% +the hamiltonian which combined + + + align:start position:0% +the hamiltonian which combined +with other terms of the hamiltonian to + + align:start position:0% +with other terms of the hamiltonian to + + + align:start position:0% +with other terms of the hamiltonian to +leave the thing being totally symmetric + + align:start position:0% +leave the thing being totally symmetric + + + align:start position:0% +leave the thing being totally symmetric +so the + + align:start position:0% +so the + + + align:start position:0% +so the +thing that I got wrong in writing + + align:start position:0% +thing that I got wrong in writing + + + align:start position:0% +thing that I got wrong in writing +lecture notes two and three previously + + align:start position:0% +lecture notes two and three previously + + + align:start position:0% +lecture notes two and three previously +was I said we're going to have a linear + + align:start position:0% +was I said we're going to have a linear + + + align:start position:0% +was I said we're going to have a linear +molecule and we have the x-band and the + + align:start position:0% +molecule and we have the x-band and the + + + align:start position:0% +molecule and we have the x-band and the +y bed and the + + align:start position:0% + + + + align:start position:0% + +problem is the way I've formulated the + + align:start position:0% +problem is the way I've formulated the + + + align:start position:0% +problem is the way I've formulated the +problem the + + align:start position:0% +problem the + + + align:start position:0% +problem the +matrix elements are the terms that I + + align:start position:0% +matrix elements are the terms that I + + + align:start position:0% +matrix elements are the terms that I +used in the Hamiltonian were not totally + + align:start position:0% +used in the Hamiltonian were not totally + + + align:start position:0% +used in the Hamiltonian were not totally +symmetric they didn't respect + + align:start position:0% +symmetric they didn't respect + + + align:start position:0% +symmetric they didn't respect +cylindrical symmetry and so that was all + + align:start position:0% +cylindrical symmetry and so that was all + + + align:start position:0% +cylindrical symmetry and so that was all +completely crazy so now I've careful to + + align:start position:0% +completely crazy so now I've careful to + + + align:start position:0% +completely crazy so now I've careful to +choose a bent molecule will + + align:start position:0% +choose a bent molecule will + + + align:start position:0% +choose a bent molecule will +come back to linear molecules eventually + + align:start position:0% +come back to linear molecules eventually + + + align:start position:0% +come back to linear molecules eventually +but the important thing is that the + + align:start position:0% +but the important thing is that the + + + align:start position:0% +but the important thing is that the +Hamiltonian if you write down something + + align:start position:0% +Hamiltonian if you write down something + + + align:start position:0% +Hamiltonian if you write down something +that thing + + align:start position:0% +that thing + + + align:start position:0% +that thing +is going to connect basis + + align:start position:0% +is going to connect basis + + + align:start position:0% +is going to connect basis +functions that belong to the same + + align:start position:0% +functions that belong to the same + + + align:start position:0% +functions that belong to the same +irreducible representation okay + + align:start position:0% +irreducible representation okay + + + align:start position:0% +irreducible representation okay +so what we want to do is take what we + + align:start position:0% +so what we want to do is take what we + + + align:start position:0% +so what we want to do is take what we +learn from allowing + + align:start position:0% +learn from allowing + + + align:start position:0% +learn from allowing +a diatomic rotating molecule and + + align:start position:0% +a diatomic rotating molecule and + + + align:start position:0% +a diatomic rotating molecule and +vibrating molecule to be an harmonic to + + align:start position:0% +vibrating molecule to be an harmonic to + + + align:start position:0% +vibrating molecule to be an harmonic to +extend that to the vibrational levels of + + align:start position:0% +extend that to the vibrational levels of + + + align:start position:0% +extend that to the vibrational levels of +a try atomic and so + + align:start position:0% +a try atomic and so + + + align:start position:0% +a try atomic and so +we're going to have diagonal and hominis + + align:start position:0% +we're going to have diagonal and hominis + + + align:start position:0% +we're going to have diagonal and hominis +in each of these modes just like what we + + align:start position:0% +in each of these modes just like what we + + + align:start position:0% +in each of these modes just like what we +did for a diatomic but while also going + + align:start position:0% +did for a diatomic but while also going + + + align:start position:0% +did for a diatomic but while also going +to allow these modes to couple to each + + align:start position:0% +to allow these modes to couple to each + + + align:start position:0% +to allow these modes to couple to each +other involving terms like q1 q2 + + align:start position:0% + + + + align:start position:0% + +say + + align:start position:0% +say + + + align:start position:0% +say +Q 2 squared or Q 1 squared cubed + + align:start position:0% +Q 2 squared or Q 1 squared cubed + + + align:start position:0% +Q 2 squared or Q 1 squared cubed +three squared + + align:start position:0% +three squared + + + align:start position:0% +three squared +okay a1 a1 b1 so we can have any powers + + align:start position:0% +okay a1 a1 b1 so we can have any powers + + + align:start position:0% +okay a1 a1 b1 so we can have any powers +of modes one and two but + + align:start position:0% +of modes one and two but + + + align:start position:0% +of modes one and two but +if we have mode 3 they have to we have + + align:start position:0% +if we have mode 3 they have to we have + + + align:start position:0% +if we have mode 3 they have to we have +to have even powers of mode 3 for + + align:start position:0% +to have even powers of mode 3 for + + + align:start position:0% +to have even powers of mode 3 for +the cup like legal coupling terms + + align:start position:0% +the cup like legal coupling terms + + + align:start position:0% +the cup like legal coupling terms +involving mode 3 so we're going to want + + align:start position:0% +involving mode 3 so we're going to want + + + align:start position:0% +involving mode 3 so we're going to want +to deal with the energy vibrational + + align:start position:0% +to deal with the energy vibrational + + + align:start position:0% +to deal with the energy vibrational +energy levels of a molecule with both + + align:start position:0% +energy levels of a molecule with both + + + align:start position:0% +energy levels of a molecule with both +diagonal and off-diagonal at Harmon + + align:start position:0% +diagonal and off-diagonal at Harmon + + + align:start position:0% +diagonal and off-diagonal at Harmon +icity and we'd like to relate the the + + align:start position:0% +icity and we'd like to relate the the + + + align:start position:0% +icity and we'd like to relate the the +things that we measure in the spectrum + + align:start position:0% +things that we measure in the spectrum + + + align:start position:0% +things that we measure in the spectrum +from differences between energy levels + + align:start position:0% +from differences between energy levels + + + align:start position:0% +from differences between energy levels +to things that are constants in the + + align:start position:0% +to things that are constants in the + + + align:start position:0% +to things that are constants in the +potential like k12 + + align:start position:0% +potential like k12 + + + align:start position:0% +potential like k12 +too because one of these two of these k + + align:start position:0% +too because one of these two of these k + + + align:start position:0% +too because one of these two of these k +1 to 2 or this k 1 133 so these are the + + align:start position:0% +1 to 2 or this k 1 133 so these are the + + + align:start position:0% +1 to 2 or this k 1 133 so these are the +new things that we want to bring into + + align:start position:0% +new things that we want to bring into + + + align:start position:0% +new things that we want to bring into +explaining + + align:start position:0% +explaining + + + align:start position:0% +explaining +the molecular energy levels are + + align:start position:0% +the molecular energy levels are + + + align:start position:0% +the molecular energy levels are +we all okay I haven't had any questions + + align:start position:0% +we all okay I haven't had any questions + + + align:start position:0% +we all okay I haven't had any questions +I have seen some responses and so + + align:start position:0% +I have seen some responses and so + + + align:start position:0% +I have seen some responses and so +I think most of you are semi + + align:start position:0% +I think most of you are semi + + + align:start position:0% +I think most of you are semi +ok here we are you all right okay + + align:start position:0% +ok here we are you all right okay + + + align:start position:0% +ok here we are you all right okay +so + + align:start position:0% + + + + align:start position:0% + +I want + + align:start position:0% +I want + + + align:start position:0% +I want +to enter illustrate the + + align:start position:0% +to enter illustrate the + + + align:start position:0% +to enter illustrate the +use of perturbation theory and Lou and + + align:start position:0% +use of perturbation theory and Lou and + + + align:start position:0% +use of perturbation theory and Lou and +the use of judgment so + + align:start position:0% + + + + align:start position:0% + +what I'm going to do is say okay omega + + align:start position:0% +what I'm going to do is say okay omega + + + align:start position:0% +what I'm going to do is say okay omega +one happens to be almost exactly 2 Omega + + align:start position:0% +one happens to be almost exactly 2 Omega + + + align:start position:0% +one happens to be almost exactly 2 Omega +2 and + + align:start position:0% + + + + align:start position:0% + +Omega 3 is approximately + + align:start position:0% +Omega 3 is approximately + + + align:start position:0% +Omega 3 is approximately +1.2 Omega 1 so + + align:start position:0% +1.2 Omega 1 so + + + align:start position:0% +1.2 Omega 1 so +this is telling you that Omega 1 and + + align:start position:0% +this is telling you that Omega 1 and + + + align:start position:0% +this is telling you that Omega 1 and +Omega 2 are resonant that + + align:start position:0% +Omega 2 are resonant that + + + align:start position:0% +Omega 2 are resonant that +we're going to get when we do + + align:start position:0% +we're going to get when we do + + + align:start position:0% +we're going to get when we do +perturbation theory we're going to get + + align:start position:0% +perturbation theory we're going to get + + + align:start position:0% +perturbation theory we're going to get +an energy denominator + + align:start position:0% +an energy denominator + + + align:start position:0% +an energy denominator +it's near zero for certain terms + + align:start position:0% +it's near zero for certain terms + + + align:start position:0% +it's near zero for certain terms +coupling the + + align:start position:0% +coupling the + + + align:start position:0% +coupling the +normal + + align:start position:0% + + + + align:start position:0% + +mode one with normal 02 but normal mode + + align:start position:0% +mode one with normal 02 but normal mode + + + align:start position:0% +mode one with normal 02 but normal mode +3 is not going to have surprising + + align:start position:0% +3 is not going to have surprising + + + align:start position:0% +3 is not going to have surprising +denominators with either mode 1 or mode + + align:start position:0% +denominators with either mode 1 or mode + + + align:start position:0% +denominators with either mode 1 or mode +2 so that means that the coupling + + align:start position:0% +2 so that means that the coupling + + + align:start position:0% +2 so that means that the coupling +between modes three two and two and + + align:start position:0% +between modes three two and two and + + + align:start position:0% +between modes three two and two and +three and one can be handled by ordinary + + align:start position:0% +three and one can be handled by ordinary + + + align:start position:0% +three and one can be handled by ordinary +non degenerate perturbation theory but + + align:start position:0% +non degenerate perturbation theory but + + + align:start position:0% +non degenerate perturbation theory but +the coupling between modes one and two + + align:start position:0% +the coupling between modes one and two + + + align:start position:0% +the coupling between modes one and two +we have to be careful so + + align:start position:0% + + + + align:start position:0% + +let us write the + + align:start position:0% + + + + align:start position:0% + +perturbation term and the + + align:start position:0% +perturbation term and the + + + align:start position:0% +perturbation term and the +perturbation term contains terms like + + align:start position:0% +perturbation term contains terms like + + + align:start position:0% +perturbation term contains terms like +this k12 to q1 + + align:start position:0% +this k12 to q1 + + + align:start position:0% +this k12 to q1 +cube 2 squared this + + align:start position:0% +cube 2 squared this + + + align:start position:0% +cube 2 squared this +just tells you what exponents to write + + align:start position:0% +just tells you what exponents to write + + + align:start position:0% +just tells you what exponents to write +up here and as soon as you know what + + align:start position:0% +up here and as soon as you know what + + + align:start position:0% +up here and as soon as you know what +exponents are right up here you know the + + align:start position:0% +exponents are right up here you know the + + + align:start position:0% +exponents are right up here you know the +matrix elements okay + + align:start position:0% +matrix elements okay + + + align:start position:0% +matrix elements okay +and then there's another term 140 k 1 + + align:start position:0% +and then there's another term 140 k 1 + + + align:start position:0% +and then there's another term 140 k 1 +133 k q1 squared q 3 square and then + + align:start position:0% +133 k q1 squared q 3 square and then + + + align:start position:0% +133 k q1 squared q 3 square and then +let's write a third term 112 k + + align:start position:0% +let's write a third term 112 k + + + align:start position:0% +let's write a third term 112 k +2 2 2 3 3 q 2 q q 3 squared so + + align:start position:0% +2 2 2 3 3 q 2 q q 3 squared so + + + align:start position:0% +2 2 2 3 3 q 2 q q 3 squared so +here is a cubic term a quartic term and + + align:start position:0% +here is a cubic term a quartic term and + + + align:start position:0% +here is a cubic term a quartic term and +a quintic term why + + align:start position:0% +a quintic term why + + + align:start position:0% +a quintic term why +did we stop why + + align:start position:0% +did we stop why + + + align:start position:0% +did we stop why +not write more there's + + align:start position:0% +not write more there's + + + align:start position:0% +not write more there's +no reason why we have to stop with + + align:start position:0% +no reason why we have to stop with + + + align:start position:0% +no reason why we have to stop with +quintic terms and there are perhaps + + align:start position:0% +quintic terms and there are perhaps + + + align:start position:0% +quintic terms and there are perhaps +cubic and quartic terms that I haven't + + align:start position:0% +cubic and quartic terms that I haven't + + + align:start position:0% +cubic and quartic terms that I haven't +included here why didn't I write them + + align:start position:0% +included here why didn't I write them + + + align:start position:0% +included here why didn't I write them +well + + align:start position:0% +well + + + align:start position:0% +well +we want the simplest possible + + align:start position:0% +we want the simplest possible + + + align:start position:0% +we want the simplest possible +representation and + + align:start position:0% + + + + align:start position:0% + +mode + + align:start position:0% +mode + + + align:start position:0% +mode +3 is not totally symmetric so + + align:start position:0% +3 is not totally symmetric so + + + align:start position:0% +3 is not totally symmetric so +anytime we're coupling to mode 3 we have + + align:start position:0% +anytime we're coupling to mode 3 we have + + + align:start position:0% +anytime we're coupling to mode 3 we have +to have two of them so + + align:start position:0% +to have two of them so + + + align:start position:0% +to have two of them so +we could conceivably have q1 + + align:start position:0% +we could conceivably have q1 + + + align:start position:0% +we could conceivably have q1 +q3 squared we could have q2 q3 squared + + align:start position:0% +q3 squared we could have q2 q3 squared + + + align:start position:0% +q3 squared we could have q2 q3 squared +but what you see here is that the + + align:start position:0% +but what you see here is that the + + + align:start position:0% +but what you see here is that the +frequencies for modes one and three are + + align:start position:0% +frequencies for modes one and three are + + + align:start position:0% +frequencies for modes one and three are +nearly + + align:start position:0% +nearly + + + align:start position:0% +nearly +the same but they're not resonant and so + + align:start position:0% +the same but they're not resonant and so + + + align:start position:0% +the same but they're not resonant and so +if you change v1 down and v3 up your + + align:start position:0% +if you change v1 down and v3 up your + + + align:start position:0% +if you change v1 down and v3 up your +you're not going to be near resonant + + align:start position:0% +you're not going to be near resonant + + + align:start position:0% +you're not going to be near resonant +you're not going to have trouble so you + + align:start position:0% +you're not going to have trouble so you + + + align:start position:0% +you're not going to have trouble so you +don't really need these terms this one + + align:start position:0% +don't really need these terms this one + + + align:start position:0% +don't really need these terms this one +though because mode 1 is roughly twice + + align:start position:0% +though because mode 1 is roughly twice + + + align:start position:0% +though because mode 1 is roughly twice +the frequency of Mo to this is a + + align:start position:0% +the frequency of Mo to this is a + + + align:start position:0% +the frequency of Mo to this is a +resonant term this is very important + + align:start position:0% + + + + align:start position:0% + +there is this one where we have modes + + align:start position:0% +there is this one where we have modes + + + align:start position:0% +there is this one where we have modes +one and three to the same power and + + align:start position:0% +one and three to the same power and + + + align:start position:0% +one and three to the same power and +they're similar in frequency they're not + + align:start position:0% +they're similar in frequency they're not + + + align:start position:0% +they're similar in frequency they're not +resonant but it's the it's the lowest + + align:start position:0% +resonant but it's the it's the lowest + + + align:start position:0% +resonant but it's the it's the lowest +ordered near resonant erm and you're + + align:start position:0% +ordered near resonant erm and you're + + + align:start position:0% +ordered near resonant erm and you're +going to have a relative you going to + + align:start position:0% +going to have a relative you going to + + + align:start position:0% +going to have a relative you going to +have some relatively small energy + + align:start position:0% +have some relatively small energy + + + align:start position:0% +have some relatively small energy +denominators will which will make this + + align:start position:0% +denominators will which will make this + + + align:start position:0% +denominators will which will make this +one import this is quintic okay but + + align:start position:0% +one import this is quintic okay but + + + align:start position:0% +one import this is quintic okay but +doesn't that resonance depend on how big + + align:start position:0% +doesn't that resonance depend on how big + + + align:start position:0% +doesn't that resonance depend on how big +say omega one is because yes so if your + + align:start position:0% +say omega one is because yes so if your + + + align:start position:0% +say omega one is because yes so if your +energy difference is lodged then that + + align:start position:0% +energy difference is lodged then that + + + align:start position:0% +energy difference is lodged then that +residents may not necessarily be right + + align:start position:0% +residents may not necessarily be right + + + align:start position:0% +residents may not necessarily be right +yellow ones that's right okay so but + + align:start position:0% +yellow ones that's right okay so but + + + align:start position:0% +yellow ones that's right okay so but +what I wanted to point out is that the + + align:start position:0% + + + + align:start position:0% + +quintic terms I think the cubic terms + + align:start position:0% +quintic terms I think the cubic terms + + + align:start position:0% +quintic terms I think the cubic terms +make generally a factor of ten larger + + align:start position:0% +make generally a factor of ten larger + + + align:start position:0% +make generally a factor of ten larger +contribution to the energy than the + + align:start position:0% +contribution to the energy than the + + + align:start position:0% +contribution to the energy than the +quartic terms and these factor 10 larger + + align:start position:0% +quartic terms and these factor 10 larger + + + align:start position:0% +quartic terms and these factor 10 larger +the de quintic terms there's more stuff + + align:start position:0% +the de quintic terms there's more stuff + + + align:start position:0% +the de quintic terms there's more stuff +that actually so + + align:start position:0% +that actually so + + + align:start position:0% +that actually so +part of that came from that scaling + + align:start position:0% +part of that came from that scaling + + + align:start position:0% +part of that came from that scaling +which I think we've lost by now Thea the + + align:start position:0% +which I think we've lost by now Thea the + + + align:start position:0% +which I think we've lost by now Thea the +fact is that I pulled out of of Q and so + + align:start position:0% +fact is that I pulled out of of Q and so + + + align:start position:0% +fact is that I pulled out of of Q and so +because each of those factors had won + + align:start position:0% +because each of those factors had won + + + align:start position:0% +because each of those factors had won +over the spirit of Omega in it and so + + align:start position:0% +over the spirit of Omega in it and so + + + align:start position:0% +over the spirit of Omega in it and so +each time you have another Q you get + + align:start position:0% +each time you have another Q you get + + + align:start position:0% +each time you have another Q you get +another factor 1 over square root of + + align:start position:0% +another factor 1 over square root of + + + align:start position:0% +another factor 1 over square root of +Omega mega is usually a thousand so you + + align:start position:0% +Omega mega is usually a thousand so you + + + align:start position:0% +Omega mega is usually a thousand so you +know square root of that is 30 and so + + align:start position:0% +know square root of that is 30 and so + + + align:start position:0% +know square root of that is 30 and so +just that factor kills you by a factor + + align:start position:0% +just that factor kills you by a factor + + + align:start position:0% +just that factor kills you by a factor +30 / q and there are other factors so + + align:start position:0% +30 / q and there are other factors so + + + align:start position:0% +30 / q and there are other factors so +you get roughly a factor of 10 / power + + align:start position:0% +you get roughly a factor of 10 / power + + + align:start position:0% +you get roughly a factor of 10 / power +of the coordinate and that means you you + + align:start position:0% +of the coordinate and that means you you + + + align:start position:0% +of the coordinate and that means you you +generally want to look very carefully at + + align:start position:0% +generally want to look very carefully at + + + align:start position:0% +generally want to look very carefully at +the cubic ones you + + align:start position:0% +the cubic ones you + + + align:start position:0% +the cubic ones you +look very careful at the quartic ones + + align:start position:0% +look very careful at the quartic ones + + + align:start position:0% +look very careful at the quartic ones +because the aquatic ones remember in + + align:start position:0% +because the aquatic ones remember in + + + align:start position:0% +because the aquatic ones remember in +perturbation theory we have energy which + + align:start position:0% +perturbation theory we have energy which + + + align:start position:0% +perturbation theory we have energy which +is for the ice level is + + align:start position:0% +is for the ice level is + + + align:start position:0% +is for the ice level is +zero + e i1 + + align:start position:0% +zero + e i1 + + + align:start position:0% +zero + e i1 +plus i2 and + + align:start position:0% + + + + align:start position:0% + +this guy comes from just H I i won it + + align:start position:0% +this guy comes from just H I i won it + + + align:start position:0% +this guy comes from just H I i won it +comes from a diagonal matrix element of + + align:start position:0% +comes from a diagonal matrix element of + + + align:start position:0% +comes from a diagonal matrix element of +the perturbation term no energy + + align:start position:0% +the perturbation term no energy + + + align:start position:0% +the perturbation term no energy +denominator and so + + align:start position:0% +denominator and so + + + align:start position:0% +denominator and so +if there is a quartic term if there is a + + align:start position:0% +if there is a quartic term if there is a + + + align:start position:0% +if there is a quartic term if there is a +term that can have a diagonal element of + + align:start position:0% +term that can have a diagonal element of + + + align:start position:0% +term that can have a diagonal element of +one of the perturbation terms that's + + align:start position:0% +one of the perturbation terms that's + + + align:start position:0% +one of the perturbation terms that's +going to be important and + + align:start position:0% +going to be important and + + + align:start position:0% +going to be important and +so + + align:start position:0% +so + + + align:start position:0% +so +we + + align:start position:0% +we + + + align:start position:0% +we +look for things where we have 11 + + align:start position:0% +look for things where we have 11 + + + align:start position:0% +look for things where we have 11 +33 or 1122 because + + align:start position:0% +33 or 1122 because + + + align:start position:0% +33 or 1122 because +as q squared has matrix element Delta V + + align:start position:0% +as q squared has matrix element Delta V + + + align:start position:0% +as q squared has matrix element Delta V +of 0 and plus and minus 2 and so you can + + align:start position:0% +of 0 and plus and minus 2 and so you can + + + align:start position:0% +of 0 and plus and minus 2 and so you can +get to Delta V sub 0 and that's the same + + align:start position:0% +get to Delta V sub 0 and that's the same + + + align:start position:0% +get to Delta V sub 0 and that's the same +thing as saying okay this is you're + + align:start position:0% +thing as saying okay this is you're + + + align:start position:0% +thing as saying okay this is you're +going to have some diagonal matrix + + align:start position:0% +going to have some diagonal matrix + + + align:start position:0% +going to have some diagonal matrix +elements of the perturbation operator + + align:start position:0% +elements of the perturbation operator + + + align:start position:0% +elements of the perturbation operator +and they become really important yes it + + align:start position:0% + + + + align:start position:0% + +isn't it + + align:start position:0% + + + + align:start position:0% + +isn't it's just you know I just wanted + + align:start position:0% +isn't it's just you know I just wanted + + + align:start position:0% +isn't it's just you know I just wanted +to include a quintic term because we + + align:start position:0% +to include a quintic term because we + + + align:start position:0% +to include a quintic term because we +want to kill it okay + + align:start position:0% +want to kill it okay + + + align:start position:0% +want to kill it okay +all right so + + align:start position:0% +all right so + + + align:start position:0% +all right so +you know that's all you know it just had + + align:start position:0% +you know that's all you know it just had + + + align:start position:0% +you know that's all you know it just had +to have an example and there's + + align:start position:0% +to have an example and there's + + + align:start position:0% +to have an example and there's +another thing that happens when + + align:start position:0% +another thing that happens when + + + align:start position:0% +another thing that happens when +you just look at the magnitudes of these + + align:start position:0% +you just look at the magnitudes of these + + + align:start position:0% +you just look at the magnitudes of these +terms they decrease by roughly a factor + + align:start position:0% +terms they decrease by roughly a factor + + + align:start position:0% +terms they decrease by roughly a factor +10 / power but the the even powers + + align:start position:0% +10 / power but the the even powers + + + align:start position:0% +10 / power but the the even powers +appear in first order and the + + align:start position:0% +appear in first order and the + + + align:start position:0% +appear in first order and the +odd powers appear only in second order + + align:start position:0% +odd powers appear only in second order + + + align:start position:0% +odd powers appear only in second order +and so it turns out that quintic and + + align:start position:0% +and so it turns out that quintic and + + + align:start position:0% +and so it turns out that quintic and +second or a cubic and second order is + + align:start position:0% +second or a cubic and second order is + + + align:start position:0% +second or a cubic and second order is +roughly the same order of magnitude as + + align:start position:0% +roughly the same order of magnitude as + + + align:start position:0% +roughly the same order of magnitude as +quartic + + align:start position:0% +quartic + + + align:start position:0% +quartic +in first order and quintic is just out + + align:start position:0% +in first order and quintic is just out + + + align:start position:0% +in first order and quintic is just out +of business because there's no quintic + + align:start position:0% +of business because there's no quintic + + + align:start position:0% +of business because there's no quintic +and first-order there's quintic only in + + align:start position:0% +and first-order there's quintic only in + + + align:start position:0% +and first-order there's quintic only in +second order that makes it roughly the + + align:start position:0% +second order that makes it roughly the + + + align:start position:0% +second order that makes it roughly the +same magnitude as sexting in zeroth + + align:start position:0% +same magnitude as sexting in zeroth + + + align:start position:0% +same magnitude as sexting in zeroth +order in first order and so you know + + align:start position:0% +order in first order and so you know + + + align:start position:0% +order in first order and so you know +this is why we stopped here we don't + + align:start position:0% +this is why we stopped here we don't + + + align:start position:0% +this is why we stopped here we don't +generally want to look at quintic terms + + align:start position:0% +generally want to look at quintic terms + + + align:start position:0% +generally want to look at quintic terms +because they're really small and they + + align:start position:0% +because they're really small and they + + + align:start position:0% +because they're really small and they +only appear squared over an energy + + align:start position:0% +only appear squared over an energy + + + align:start position:0% +only appear squared over an energy +difference okay + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +we're going to want to get + + align:start position:0% + + + + align:start position:0% + +from perturbation theory the + + align:start position:0% +from perturbation theory the + + + align:start position:0% +from perturbation theory the +expressions in this general energy + + align:start position:0% +expressions in this general energy + + + align:start position:0% +expressions in this general energy +expression i just use a bold v to + + align:start position:0% +expression i just use a bold v to + + + align:start position:0% +expression i just use a bold v to +indicate all the vibrational modes + + align:start position:0% +indicate all the vibrational modes + + + align:start position:0% +indicate all the vibrational modes +instead of having to write e v1 + + align:start position:0% +instead of having to write e v1 + + + align:start position:0% +instead of having to write e v1 +v2 v3 but that's what this means and so + + align:start position:0% +v2 v3 but that's what this means and so + + + align:start position:0% +v2 v3 but that's what this means and so +we're going to have omega + + align:start position:0% +we're going to have omega + + + align:start position:0% +we're going to have omega +i VI plus a half plus + + align:start position:0% +i VI plus a half plus + + + align:start position:0% +i VI plus a half plus +i J + + align:start position:0% +i J + + + align:start position:0% +i J +I greater + + align:start position:0% +I greater + + + align:start position:0% +I greater +than or equal to j x + + align:start position:0% +than or equal to j x + + + align:start position:0% +than or equal to j x +i J VI plus + + align:start position:0% +i J VI plus + + + align:start position:0% +i J VI plus +a half be J + + align:start position:0% +a half be J + + + align:start position:0% +a half be J +okay right VJ plus a half and + + align:start position:0% +okay right VJ plus a half and + + + align:start position:0% +okay right VJ plus a half and +so + + align:start position:0% +so + + + align:start position:0% +so +we're going to have three omegas we're + + align:start position:0% +we're going to have three omegas we're + + + align:start position:0% +we're going to have three omegas we're +going to have 6 + + align:start position:0% +going to have 6 + + + align:start position:0% +going to have 6 +x's and we're going to want to get the + + align:start position:0% +x's and we're going to want to get the + + + align:start position:0% +x's and we're going to want to get the +three omegas and the 6 x's out of the + + align:start position:0% +three omegas and the 6 x's out of the + + + align:start position:0% +three omegas and the 6 x's out of the +put + + align:start position:0% +put + + + align:start position:0% +put +the expression for H prime we have these + + align:start position:0% +the expression for H prime we have these + + + align:start position:0% +the expression for H prime we have these +this we don't have that and we have the + + align:start position:0% +this we don't have that and we have the + + + align:start position:0% +this we don't have that and we have the +the mass factors and the force constants + + align:start position:0% +the mass factors and the force constants + + + align:start position:0% +the mass factors and the force constants +so we're + + align:start position:0% +so we're + + + align:start position:0% +so we're +going to use perturbation theory to get + + align:start position:0% +going to use perturbation theory to get + + + align:start position:0% +going to use perturbation theory to get +all that information + + align:start position:0% + + + + align:start position:0% + +okay now + + align:start position:0% +okay now + + + align:start position:0% +okay now +it doesn't really matter if I don't + + align:start position:0% +it doesn't really matter if I don't + + + align:start position:0% +it doesn't really matter if I don't +finish these notes I won't because I've + + align:start position:0% +finish these notes I won't because I've + + + align:start position:0% +finish these notes I won't because I've +already done the important stuff you + + align:start position:0% +already done the important stuff you + + + align:start position:0% +already done the important stuff you +know the important thing is that we're + + align:start position:0% +know the important thing is that we're + + + align:start position:0% +know the important thing is that we're +going to use perturbation theory we have + + align:start position:0% +going to use perturbation theory we have + + + align:start position:0% +going to use perturbation theory we have +a trick for simplifying all of the + + align:start position:0% +a trick for simplifying all of the + + + align:start position:0% +a trick for simplifying all of the +matrix elements we have a way of telling + + align:start position:0% +matrix elements we have a way of telling + + + align:start position:0% +matrix elements we have a way of telling +a computer how to evaluate all the + + align:start position:0% +a computer how to evaluate all the + + + align:start position:0% +a computer how to evaluate all the +matrix elements and how to assemble them + + align:start position:0% +matrix elements and how to assemble them + + + align:start position:0% +matrix elements and how to assemble them +okay + + align:start position:0% +okay + + + align:start position:0% +okay +but there are some more really beautiful + + align:start position:0% +but there are some more really beautiful + + + align:start position:0% +but there are some more really beautiful +stuff here that I want to talk + + align:start position:0% +stuff here that I want to talk + + + align:start position:0% +stuff here that I want to talk +about a little bit + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so + + align:start position:0% +so + + + align:start position:0% +so +you know the formula for the first order + + align:start position:0% +you know the formula for the first order + + + align:start position:0% +you know the formula for the first order +correction that to the energy that's the + + align:start position:0% +correction that to the energy that's the + + + align:start position:0% +correction that to the energy that's the +diagonal element of the perturbation + + align:start position:0% +diagonal element of the perturbation + + + align:start position:0% +diagonal element of the perturbation +term you know the formula for second + + align:start position:0% +term you know the formula for second + + + align:start position:0% +term you know the formula for second +order correction we have e to I is going + + align:start position:0% +order correction we have e to I is going + + + align:start position:0% +order correction we have e to I is going +to be the sum over j not equal to i h i + + align:start position:0% +to be the sum over j not equal to i h i + + + align:start position:0% +to be the sum over j not equal to i h i +j HJ + + align:start position:0% +j HJ + + + align:start position:0% +j HJ +I / + + align:start position:0% +I / + + + align:start position:0% +I / +e I 0 minus e j you know these things + + align:start position:0% +e I 0 minus e j you know these things + + + align:start position:0% +e I 0 minus e j you know these things +are just combinations of omegas so + + align:start position:0% +are just combinations of omegas so + + + align:start position:0% +are just combinations of omegas so +the energy nominees are really easy to + + align:start position:0% +the energy nominees are really easy to + + + align:start position:0% +the energy nominees are really easy to +write because it's basically you know + + align:start position:0% +write because it's basically you know + + + align:start position:0% +write because it's basically you know +you have energy levels which are + + align:start position:0% +you have energy levels which are + + + align:start position:0% +you have energy levels which are +expressed as you know three quantum mode + + align:start position:0% +expressed as you know three quantum mode + + + align:start position:0% +expressed as you know three quantum mode +1 plus 2 of mode 2 etc and you take + + align:start position:0% +1 plus 2 of mode 2 etc and you take + + + align:start position:0% +1 plus 2 of mode 2 etc and you take +those differences it's just some number + + align:start position:0% +those differences it's just some number + + + align:start position:0% +those differences it's just some number +times + + align:start position:0% + + + + align:start position:0% + +the different values of Omega so this is + + align:start position:0% +the different values of Omega so this is + + + align:start position:0% +the different values of Omega so this is +easy these are easy to because they're + + align:start position:0% +easy these are easy to because they're + + + align:start position:0% +easy these are easy to because they're +matrix elements of things like q1 q2 + + align:start position:0% +matrix elements of things like q1 q2 + + + align:start position:0% +matrix elements of things like q1 q2 +squared so you could you write these + + align:start position:0% +squared so you could you write these + + + align:start position:0% +squared so you could you write these +things down and generally + + align:start position:0% +things down and generally + + + align:start position:0% +things down and generally +their matrix element squared so you get + + align:start position:0% +their matrix element squared so you get + + + align:start position:0% +their matrix element squared so you get +square roots of things from this and you + + align:start position:0% +square roots of things from this and you + + + align:start position:0% +square roots of things from this and you +just kill the square roots okay + + align:start position:0% +just kill the square roots okay + + + align:start position:0% +just kill the square roots okay +and so there's all sorts of very + + align:start position:0% +and so there's all sorts of very + + + align:start position:0% +and so there's all sorts of very +wonderful things but now again + + align:start position:0% +wonderful things but now again + + + align:start position:0% +wonderful things but now again +suppose you had q1 q2 squared you want + + align:start position:0% +suppose you had q1 q2 squared you want + + + align:start position:0% +suppose you had q1 q2 squared you want +to you want to make a list of all of the + + align:start position:0% +to you want to make a list of all of the + + + align:start position:0% +to you want to make a list of all of the +possible non zero matrix elements so we + + align:start position:0% +possible non zero matrix elements so we + + + align:start position:0% +possible non zero matrix elements so we +have Delta v1 plus and minus 1 we have + + align:start position:0% +have Delta v1 plus and minus 1 we have + + + align:start position:0% +have Delta v1 plus and minus 1 we have +Delta V 2 of 0 plus or minus 2 and so + + align:start position:0% +Delta V 2 of 0 plus or minus 2 and so + + + align:start position:0% +Delta V 2 of 0 plus or minus 2 and so +there are there + + align:start position:0% +there are there + + + align:start position:0% +there are there +are if + + align:start position:0% + + + + align:start position:0% + +we write Delta V 1 Delta V 2 for + + align:start position:0% +we write Delta V 1 Delta V 2 for + + + align:start position:0% +we write Delta V 1 Delta V 2 for +the possible selection rules we have + + align:start position:0% +the possible selection rules we have + + + align:start position:0% +the possible selection rules we have +plus 1 plus 2 + + align:start position:0% +plus 1 plus 2 + + + align:start position:0% +plus 1 plus 2 +minus + + align:start position:0% +minus + + + align:start position:0% +minus +one plus two plus one + + align:start position:0% +one plus two plus one + + + align:start position:0% +one plus two plus one +minus + + align:start position:0% +minus + + + align:start position:0% +minus +two minus + + align:start position:0% + + + + align:start position:0% + +one minus two so + + align:start position:0% +one minus two so + + + align:start position:0% +one minus two so +there are four possible combinations of + + align:start position:0% +there are four possible combinations of + + + align:start position:0% +there are four possible combinations of +not dial matrix' now as soon as you + + align:start position:0% +not dial matrix' now as soon as you + + + align:start position:0% +not dial matrix' now as soon as you +write this you know oh well my goodness + + align:start position:0% +write this you know oh well my goodness + + + align:start position:0% +write this you know oh well my goodness +a 1 + + align:start position:0% +a 1 + + + align:start position:0% +a 1 +dagger a 2 dagger squared the the term + + align:start position:0% +dagger a 2 dagger squared the the term + + + align:start position:0% +dagger a 2 dagger squared the the term +that you want that that multiple that + + align:start position:0% +that you want that that multiple that + + + align:start position:0% +that you want that that multiple that +controls this guy is that the term that + + align:start position:0% +controls this guy is that the term that + + + align:start position:0% +controls this guy is that the term that +you want for this is a 1 a 2 dagger + + align:start position:0% +you want for this is a 1 a 2 dagger + + + align:start position:0% +you want for this is a 1 a 2 dagger +squared so all of the possible non zero + + align:start position:0% +squared so all of the possible non zero + + + align:start position:0% +squared so all of the possible non zero +matrix elements tell you go and get this + + align:start position:0% +matrix elements tell you go and get this + + + align:start position:0% +matrix elements tell you go and get this +combination of a Zen a daggers and what + + align:start position:0% +combination of a Zen a daggers and what + + + align:start position:0% +combination of a Zen a daggers and what +was the number in front of that that you + + align:start position:0% +was the number in front of that that you + + + align:start position:0% +was the number in front of that that you +got when you expand it cute this + + align:start position:0% +got when you expand it cute this + + + align:start position:0% +got when you expand it cute this +is very easy to tell the computer what + + align:start position:0% +is very easy to tell the computer what + + + align:start position:0% +is very easy to tell the computer what +to do and so you + + align:start position:0% +to do and so you + + + align:start position:0% +to do and so you +write down an operator that expresses + + align:start position:0% +write down an operator that expresses + + + align:start position:0% +write down an operator that expresses +the an ominous City you break it up into + + align:start position:0% +the an ominous City you break it up into + + + align:start position:0% +the an ominous City you break it up into +selection rules the selection rules + + align:start position:0% +selection rules the selection rules + + + align:start position:0% +selection rules the selection rules +tells you which combination of a Zen a + + align:start position:0% +tells you which combination of a Zen a + + + align:start position:0% +tells you which combination of a Zen a +daggers and then the little algebra you + + align:start position:0% +daggers and then the little algebra you + + + align:start position:0% +daggers and then the little algebra you +did at the beginning and the cue to the + + align:start position:0% +did at the beginning and the cue to the + + + align:start position:0% +did at the beginning and the cue to the +what enables you to finish the job the + + align:start position:0% +what enables you to finish the job the + + + align:start position:0% +what enables you to finish the job the +rest is awful because you're + + align:start position:0% +rest is awful because you're + + + align:start position:0% +rest is awful because you're +manipulating these huge sums of things + + align:start position:0% +manipulating these huge sums of things + + + align:start position:0% +manipulating these huge sums of things +which involve matrix + + align:start position:0% +which involve matrix + + + align:start position:0% +which involve matrix +elements of lots of constants in the + + align:start position:0% +elements of lots of constants in the + + + align:start position:0% +elements of lots of constants in the +numerator and in the denominator you + + align:start position:0% +numerator and in the denominator you + + + align:start position:0% +numerator and in the denominator you +have differences in omega ones and Omega + + align:start position:0% +have differences in omega ones and Omega + + + align:start position:0% +have differences in omega ones and Omega +2 s or sums it will make a ones in omega + + align:start position:0% +2 s or sums it will make a ones in omega + + + align:start position:0% +2 s or sums it will make a ones in omega +two but it's all automatic and you can + + align:start position:0% +two but it's all automatic and you can + + + align:start position:0% +two but it's all automatic and you can +work that out okay + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% + + + + align:start position:0% + +you're proceeding along here you're + + align:start position:0% +you're proceeding along here you're + + + align:start position:0% +you're proceeding along here you're +systematically writing down all the + + align:start position:0% +systematically writing down all the + + + align:start position:0% +systematically writing down all the +terms in the perturbation expansion the + + align:start position:0% +terms in the perturbation expansion the + + + align:start position:0% +terms in the perturbation expansion the +second-order perturbation expansion and + + align:start position:0% +second-order perturbation expansion and + + + align:start position:0% +second-order perturbation expansion and +all of a sudden you get some number / 0 + + align:start position:0% +all of a sudden you get some number / 0 + + + align:start position:0% +all of a sudden you get some number / 0 +and you + + align:start position:0% +and you + + + align:start position:0% +and you +know that this is bed and + + align:start position:0% +know that this is bed and + + + align:start position:0% +know that this is bed and +that + + align:start position:0% +that + + + align:start position:0% +that +corresponds to a resonance you know as + + align:start position:0% +corresponds to a resonance you know as + + + align:start position:0% +corresponds to a resonance you know as +soon as i wrote Omega 1 is approximately + + align:start position:0% +soon as i wrote Omega 1 is approximately + + + align:start position:0% +soon as i wrote Omega 1 is approximately +equal to Omega 2 2 Omega 2 we're going + + align:start position:0% +equal to Omega 2 2 Omega 2 we're going + + + align:start position:0% +equal to Omega 2 2 Omega 2 we're going +to have a resonance whenever we have + + align:start position:0% +to have a resonance whenever we have + + + align:start position:0% +to have a resonance whenever we have +Delta V 1 is equal to minus Delta V + + align:start position:0% +Delta V 1 is equal to minus Delta V + + + align:start position:0% +Delta V 1 is equal to minus Delta V +minus 2 Delta V 2 and so we can do this + + align:start position:0% +minus 2 Delta V 2 and so we can do this + + + align:start position:0% +minus 2 Delta V 2 and so we can do this +two different ways so they're going to + + align:start position:0% +two different ways so they're going to + + + align:start position:0% +two different ways so they're going to +be two different resonance terms and as + + align:start position:0% +be two different resonance terms and as + + + align:start position:0% +be two different resonance terms and as +long as we stay away from those + + align:start position:0% +long as we stay away from those + + + align:start position:0% +long as we stay away from those +resonance terms second order + + align:start position:0% +resonance terms second order + + + align:start position:0% +resonance terms second order +perturbation theory is fine but we have + + align:start position:0% +perturbation theory is fine but we have + + + align:start position:0% +perturbation theory is fine but we have +to do something that respects + + align:start position:0% +to do something that respects + + + align:start position:0% +to do something that respects +these resonant terms so what do you do + + align:start position:0% +these resonant terms so what do you do + + + align:start position:0% +these resonant terms so what do you do +we have non degenerate perturbation + + align:start position:0% +we have non degenerate perturbation + + + align:start position:0% +we have non degenerate perturbation +theory that means not degenerate well + + align:start position:0% +theory that means not degenerate well + + + align:start position:0% +theory that means not degenerate well +if you have degeneracy you have to say + + align:start position:0% +if you have degeneracy you have to say + + + align:start position:0% +if you have degeneracy you have to say +all forget order sorting I have to solve + + align:start position:0% +all forget order sorting I have to solve + + + align:start position:0% +all forget order sorting I have to solve +a secular equation I have to write down + + align:start position:0% +a secular equation I have to write down + + + align:start position:0% +a secular equation I have to write down +a block + + align:start position:0% +a block + + + align:start position:0% +a block +of the Hamiltonian which I find the + + align:start position:0% +of the Hamiltonian which I find the + + + align:start position:0% +of the Hamiltonian which I find the +eigenvalues and eigenvectors of and that + + align:start position:0% +eigenvalues and eigenvectors of and that + + + align:start position:0% +eigenvalues and eigenvectors of and that +deals with the residents and so it just + + align:start position:0% +deals with the residents and so it just + + + align:start position:0% +deals with the residents and so it just +tells okay so suppose we have what we + + align:start position:0% +tells okay so suppose we have what we + + + align:start position:0% +tells okay so suppose we have what we +call a poly add quantum number this is + + align:start position:0% +call a poly add quantum number this is + + + align:start position:0% +call a poly add quantum number this is +just a way of saying well + + align:start position:0% +just a way of saying well + + + align:start position:0% +just a way of saying well +what's resonant suppo and that is to v1 + + align:start position:0% +what's resonant suppo and that is to v1 + + + align:start position:0% +what's resonant suppo and that is to v1 +plus v2 okay + + align:start position:0% +plus v2 okay + + + align:start position:0% +plus v2 okay +and so this is a little code that says I + + align:start position:0% +and so this is a little code that says I + + + align:start position:0% +and so this is a little code that says I +suppose I have the tenth p equals 10 I + + align:start position:0% +suppose I have the tenth p equals 10 I + + + align:start position:0% +suppose I have the tenth p equals 10 I +can + + align:start position:0% +can + + + align:start position:0% +can +then write down for p equals 10 all of + + align:start position:0% +then write down for p equals 10 all of + + + align:start position:0% +then write down for p equals 10 all of +the zero order states that are resonant + + align:start position:0% +the zero order states that are resonant + + + align:start position:0% +the zero order states that are resonant +let's just do it you know I don't have P + + align:start position:0% +let's just do it you know I don't have P + + + align:start position:0% +let's just do it you know I don't have P +equals 10 in the notes so i know that to + + align:start position:0% +equals 10 in the notes so i know that to + + + align:start position:0% +equals 10 in the notes so i know that to +get p equals 10 i can do that with zero + + align:start position:0% +get p equals 10 i can do that with zero + + + align:start position:0% +get p equals 10 i can do that with zero +right + + align:start position:0% +right + + + align:start position:0% +right +I can get that with 18 I can 2634 + + align:start position:0% + + + + align:start position:0% + +to + + align:start position:0% +to + + + align:start position:0% +to +oops + + align:start position:0% +oops + + + align:start position:0% +oops + + align:start position:0% + + + align:start position:0% +and 50 + + align:start position:0% +and 50 + + + align:start position:0% +and 50 +one two three four five six so there's + + align:start position:0% +one two three four five six so there's + + + align:start position:0% +one two three four five six so there's +60 order states in this Holly ad which + + align:start position:0% +60 order states in this Holly ad which + + + align:start position:0% +60 order states in this Holly ad which +with p equals 10 so that's a scaling + + align:start position:0% +with p equals 10 so that's a scaling + + + align:start position:0% +with p equals 10 so that's a scaling +rule for membership that's a rule that's + + align:start position:0% +rule for membership that's a rule that's + + + align:start position:0% +rule for membership that's a rule that's +okay I've recognized what is the + + align:start position:0% +okay I've recognized what is the + + + align:start position:0% +okay I've recognized what is the +resonance condition that combining + + align:start position:0% +resonance condition that combining + + + align:start position:0% +resonance condition that combining +things this way and so since Omega 1 is + + align:start position:0% +things this way and so since Omega 1 is + + + align:start position:0% +things this way and so since Omega 1 is +twice as big as Omega 2 for each quantum + + align:start position:0% +twice as big as Omega 2 for each quantum + + + align:start position:0% +twice as big as Omega 2 for each quantum +in omega 1 I get two points for each + + align:start position:0% +in omega 1 I get two points for each + + + align:start position:0% +in omega 1 I get two points for each +quantum and Omega 1 I get one point + + align:start position:0% +quantum and Omega 1 I get one point + + + align:start position:0% +quantum and Omega 1 I get one point +that's where these polyethers come from + + align:start position:0% +that's where these polyethers come from + + + align:start position:0% +that's where these polyethers come from +and then as soon as I say what this is I + + align:start position:0% +and then as soon as I say what this is I + + + align:start position:0% +and then as soon as I say what this is I +discover that i have a six by six or + + align:start position:0% +discover that i have a six by six or + + + align:start position:0% +discover that i have a six by six or +whatever matrix that I have to + + align:start position:0% +whatever matrix that I have to + + + align:start position:0% +whatever matrix that I have to +diagonalize and then I recognize that i + + align:start position:0% +diagonalize and then I recognize that i + + + align:start position:0% +diagonalize and then I recognize that i +only have couplings between successive + + align:start position:0% +only have couplings between successive + + + align:start position:0% +only have couplings between successive +members in this list and so + + align:start position:0% +members in this list and so + + + align:start position:0% +members in this list and so +i can write the matrix and it's going to + + align:start position:0% +i can write the matrix and it's going to + + + align:start position:0% +i can write the matrix and it's going to +have the form of in + + align:start position:0% + + + + align:start position:0% + +this particular one zeros numbers + + align:start position:0% +this particular one zeros numbers + + + align:start position:0% +this particular one zeros numbers +zeros + + align:start position:0% + + + + align:start position:0% + +and so then the job is just to fill out + + align:start position:0% +and so then the job is just to fill out + + + align:start position:0% +and so then the job is just to fill out +these numbers and the + + align:start position:0% + + + + align:start position:0% + +nice thing about this is all the trash + + align:start position:0% +nice thing about this is all the trash + + + align:start position:0% +nice thing about this is all the trash +comes out in front and these are just + + align:start position:0% +comes out in front and these are just + + + align:start position:0% +comes out in front and these are just +square roots of integers and + + align:start position:0% + + + + align:start position:0% + +so you all of a sudden you get an + + align:start position:0% +so you all of a sudden you get an + + + align:start position:0% +so you all of a sudden you get an +effective Hamiltonian with trash which + + align:start position:0% +effective Hamiltonian with trash which + + + align:start position:0% +effective Hamiltonian with trash which +you can or cannot if you choose to deal + + align:start position:0% +you can or cannot if you choose to deal + + + align:start position:0% +you can or cannot if you choose to deal +with and then the critical structure + + align:start position:0% +with and then the critical structure + + + align:start position:0% +with and then the critical structure +which is universal along + + align:start position:0% +which is universal along + + + align:start position:0% +which is universal along +the diagonal and depending on which + + align:start position:0% +the diagonal and depending on which + + + align:start position:0% +the diagonal and depending on which +value of P you get a different matrix + + align:start position:0% +value of P you get a different matrix + + + align:start position:0% +value of P you get a different matrix +but + + align:start position:0% +but + + + align:start position:0% +but +it's got the same structure and so + + align:start position:0% +it's got the same structure and so + + + align:start position:0% +it's got the same structure and so +and there's only one thing that controls + + align:start position:0% +and there's only one thing that controls + + + align:start position:0% +and there's only one thing that controls +the energy levels and that's this trash + + align:start position:0% +the energy levels and that's this trash + + + align:start position:0% +the energy levels and that's this trash +out here and + + align:start position:0% + + + + align:start position:0% + +so what you've done is you've dealt with + + align:start position:0% +so what you've done is you've dealt with + + + align:start position:0% +so what you've done is you've dealt with +a resonance that's a classical resonance + + align:start position:0% +a resonance that's a classical resonance + + + align:start position:0% +a resonance that's a classical resonance +because you've got two things that + + align:start position:0% +because you've got two things that + + + align:start position:0% +because you've got two things that +oscillate it integer multiples it's a + + align:start position:0% +oscillate it integer multiples it's a + + + align:start position:0% +oscillate it integer multiples it's a +quantum mechanical resonance and you + + align:start position:0% +quantum mechanical resonance and you + + + align:start position:0% +quantum mechanical resonance and you +just wrote down some thing some problem + + align:start position:0% +just wrote down some thing some problem + + + align:start position:0% +just wrote down some thing some problem +that you have to solve to get the + + align:start position:0% +that you have to solve to get the + + + align:start position:0% +that you have to solve to get the +correct linear combination of states + + align:start position:0% +correct linear combination of states + + + align:start position:0% +correct linear combination of states +that deal with that resonance now the + + align:start position:0% +that deal with that resonance now the + + + align:start position:0% +that deal with that resonance now the +next thing you have to do is to say well + + align:start position:0% +next thing you have to do is to say well + + + align:start position:0% +next thing you have to do is to say well +hold your horses we could do this but + + align:start position:0% +hold your horses we could do this but + + + align:start position:0% +hold your horses we could do this but +there are and + + align:start position:0% + + + + align:start position:0% + +this is the last thing I'm going to say + + align:start position:0% +this is the last thing I'm going to say + + + align:start position:0% +this is the last thing I'm going to say +so you don't have to get impatient i'm + + align:start position:0% +so you don't have to get impatient i'm + + + align:start position:0% +so you don't have to get impatient i'm +not going to cheat this again we're done + + align:start position:0% +not going to cheat this again we're done + + + align:start position:0% +not going to cheat this again we're done +but so the hamiltonian is arranged in + + align:start position:0% +but so the hamiltonian is arranged in + + + align:start position:0% +but so the hamiltonian is arranged in +the form of blocks along the diagonal + + align:start position:0% +the form of blocks along the diagonal + + + align:start position:0% +the form of blocks along the diagonal +and as you go down the block get bigger + + align:start position:0% +and as you go down the block get bigger + + + align:start position:0% +and as you go down the block get bigger +and bigger each of these blocks is + + align:start position:0% +and bigger each of these blocks is + + + align:start position:0% +and bigger each of these blocks is +generated by the same constants in the + + align:start position:0% +generated by the same constants in the + + + align:start position:0% +generated by the same constants in the +previous one and so there's nothing new + + align:start position:0% +previous one and so there's nothing new + + + align:start position:0% +previous one and so there's nothing new +except that you have to write them down + + align:start position:0% +except that you have to write them down + + + align:start position:0% +except that you have to write them down +but sometimes there are matrix elements + + align:start position:0% +but sometimes there are matrix elements + + + align:start position:0% +but sometimes there are matrix elements +outside of blocks and you have to fold + + align:start position:0% +outside of blocks and you have to fold + + + align:start position:0% +outside of blocks and you have to fold +them into the blocks before you + + align:start position:0% +them into the blocks before you + + + align:start position:0% +them into the blocks before you +diagonalize them that's + + align:start position:0% +diagonalize them that's + + + align:start position:0% +diagonalize them that's +called a van vleck transformation it's a + + align:start position:0% +called a van vleck transformation it's a + + + align:start position:0% +called a van vleck transformation it's a +fancy kind of second order perturbation + + align:start position:0% +fancy kind of second order perturbation + + + align:start position:0% +fancy kind of second order perturbation +theory and so what you do is you + + align:start position:0% +theory and so what you do is you + + + align:start position:0% +theory and so what you do is you +say okay if there is an out of block + + align:start position:0% +say okay if there is an out of block + + + align:start position:0% +say okay if there is an out of block +state that interact strongly between + + align:start position:0% +state that interact strongly between + + + align:start position:0% +state that interact strongly between +these + + align:start position:0% +these + + + align:start position:0% +these +it has a strong enough interaction + + align:start position:0% +it has a strong enough interaction + + + align:start position:0% +it has a strong enough interaction +between these two that could mess up the + + align:start position:0% +between these two that could mess up the + + + align:start position:0% +between these two that could mess up the +the detailed structure in here we fold + + align:start position:0% +the detailed structure in here we fold + + + align:start position:0% +the detailed structure in here we fold +the effect of this dated here and so + + align:start position:0% +the effect of this dated here and so + + + align:start position:0% +the effect of this dated here and so +what do you do you say the + + align:start position:0% +what do you do you say the + + + align:start position:0% +what do you do you say the +transformed + + align:start position:0% +transformed + + + align:start position:0% +transformed +Hamiltonian correcting for out of block + + align:start position:0% +Hamiltonian correcting for out of block + + + align:start position:0% +Hamiltonian correcting for out of block +States so here we have the IJ element in + + align:start position:0% +States so here we have the IJ element in + + + align:start position:0% +States so here we have the IJ element in +a block we + + align:start position:0% +a block we + + + align:start position:0% +a block we +write that as I que + + align:start position:0% +write that as I que + + + align:start position:0% +write that as I que +que je and these are perturbation terms + + align:start position:0% +que je and these are perturbation terms + + + align:start position:0% +que je and these are perturbation terms +sum over K and we have e i0 + + align:start position:0% +sum over K and we have e i0 + + + align:start position:0% +sum over K and we have e i0 +plus e j 0 over 2 minus e k 0 now this + + align:start position:0% +plus e j 0 over 2 minus e k 0 now this + + + align:start position:0% +plus e j 0 over 2 minus e k 0 now this +is a formula that was proposed by Van + + align:start position:0% +is a formula that was proposed by Van + + + align:start position:0% +is a formula that was proposed by Van +Vleck and you + + align:start position:0% +Vleck and you + + + align:start position:0% +Vleck and you +know it looks just like second-order + + align:start position:0% +know it looks just like second-order + + + align:start position:0% +know it looks just like second-order +perturbation theory we have a product of + + align:start position:0% +perturbation theory we have a product of + + + align:start position:0% +perturbation theory we have a product of +off diagonal matrix elements but it's a + + align:start position:0% +off diagonal matrix elements but it's a + + + align:start position:0% +off diagonal matrix elements but it's a +product where the initial and final + + align:start position:0% +product where the initial and final + + + align:start position:0% +product where the initial and final +index is different and this + + align:start position:0% +index is different and this + + + align:start position:0% +index is different and this +is an average over the initial and final + + align:start position:0% +is an average over the initial and final + + + align:start position:0% +is an average over the initial and final +zero order states within the block and + + align:start position:0% +zero order states within the block and + + + align:start position:0% +zero order states within the block and +that's not a big deal because the energy + + align:start position:0% +that's not a big deal because the energy + + + align:start position:0% +that's not a big deal because the energy +difference within a block is small + + align:start position:0% +difference within a block is small + + + align:start position:0% +difference within a block is small +compared to the difference between + + align:start position:0% +compared to the difference between + + + align:start position:0% +compared to the difference between +states in the block and outside the + + align:start position:0% +states in the block and outside the + + + align:start position:0% +states in the block and outside the +block and so basically this is just a + + align:start position:0% +block and so basically this is just a + + + align:start position:0% +block and so basically this is just a +computational + + align:start position:0% +computational + + + align:start position:0% +computational +simplification and so we have energy + + align:start position:0% +simplification and so we have energy + + + align:start position:0% +simplification and so we have energy +differences we have matrix elements and + + align:start position:0% +differences we have matrix elements and + + + align:start position:0% +differences we have matrix elements and +that provides us with a way of + + align:start position:0% +that provides us with a way of + + + align:start position:0% +that provides us with a way of +compensating for the effect of out of + + align:start position:0% +compensating for the effect of out of + + + align:start position:0% +compensating for the effect of out of +block not resonant terms on the intra + + align:start position:0% +block not resonant terms on the intra + + + align:start position:0% +block not resonant terms on the intra +block energies and that improves the + + align:start position:0% +block energies and that improves the + + + align:start position:0% +block energies and that improves the +accuracy of the calculation and that's + + align:start position:0% +accuracy of the calculation and that's + + + align:start position:0% +accuracy of the calculation and that's +really the whole story and so + + align:start position:0% +really the whole story and so + + + align:start position:0% +really the whole story and so +I don't want to say any more this + + align:start position:0% +I don't want to say any more this + + + align:start position:0% +I don't want to say any more this +algebraically + + align:start position:0% +algebraically + + + align:start position:0% +algebraically +is awful but again you know once you've + + align:start position:0% +is awful but again you know once you've + + + align:start position:0% +is awful but again you know once you've +taught your computer the other stuff you + + align:start position:0% +taught your computer the other stuff you + + + align:start position:0% +taught your computer the other stuff you +can teach the computer this too because + + align:start position:0% +can teach the computer this too because + + + align:start position:0% +can teach the computer this too because +there's nothing new here and + + align:start position:0% +there's nothing new here and + + + align:start position:0% +there's nothing new here and +there's nothing new here + + align:start position:0% +there's nothing new here + + + align:start position:0% +there's nothing new here +and just integers times trash and + + align:start position:0% + + + + align:start position:0% + +so so + + align:start position:0% +so so + + + align:start position:0% +so so +that's it I this is an example of you + + align:start position:0% +that's it I this is an example of you + + + align:start position:0% +that's it I this is an example of you +know you start with the effective + + align:start position:0% +know you start with the effective + + + align:start position:0% +know you start with the effective +Hamiltonian for a one-dimensional system + + align:start position:0% +Hamiltonian for a one-dimensional system + + + align:start position:0% +Hamiltonian for a one-dimensional system +and you deal with that are Missy you + + align:start position:0% +and you deal with that are Missy you + + + align:start position:0% +and you deal with that are Missy you +discover that you simplify the coupling + + align:start position:0% +discover that you simplify the coupling + + + align:start position:0% +discover that you simplify the coupling +terms in to a form that's really really + + align:start position:0% +terms in to a form that's really really + + + align:start position:0% +terms in to a form that's really really +convenient for sticking it to mr. + + align:start position:0% +convenient for sticking it to mr. + + + align:start position:0% +convenient for sticking it to mr. +computer and then you say okay well now + + align:start position:0% +computer and then you say okay well now + + + align:start position:0% +computer and then you say okay well now +we have several oscillators and we have + + align:start position:0% +we have several oscillators and we have + + + align:start position:0% +we have several oscillators and we have +the diagonal anharmonicity we know about + + align:start position:0% +the diagonal anharmonicity we know about + + + align:start position:0% +the diagonal anharmonicity we know about +that and we have the cross an ominous + + align:start position:0% +that and we have the cross an ominous + + + align:start position:0% +that and we have the cross an ominous +ease between the different modes and we + + align:start position:0% +ease between the different modes and we + + + align:start position:0% +ease between the different modes and we +just represent them phenomenologically + + align:start position:0% +just represent them phenomenologically + + + align:start position:0% +just represent them phenomenologically +as coupling terms and we have a sense + + align:start position:0% +as coupling terms and we have a sense + + + align:start position:0% +as coupling terms and we have a sense +for which are the important ones and + + align:start position:0% +for which are the important ones and + + + align:start position:0% +for which are the important ones and +then we say be careful of residence and + + align:start position:0% +then we say be careful of residence and + + + align:start position:0% +then we say be careful of residence and +we have a way of fixing residents and + + align:start position:0% +we have a way of fixing residents and + + + align:start position:0% +we have a way of fixing residents and +then we're done we we have a machine + + align:start position:0% +then we're done we we have a machine + + + align:start position:0% +then we're done we we have a machine +that can represent the energy levels it + + align:start position:0% +that can represent the energy levels it + + + align:start position:0% +that can represent the energy levels it +will not only represent the energy + + align:start position:0% +will not only represent the energy + + + align:start position:0% +will not only represent the energy +levels it will give you things that are + + align:start position:0% +levels it will give you things that are + + + align:start position:0% +levels it will give you things that are +almost like wave functions with which + + align:start position:0% +almost like wave functions with which + + + align:start position:0% +almost like wave functions with which +you can calculate properties other than + + align:start position:0% +you can calculate properties other than + + + align:start position:0% +you can calculate properties other than +the energy but you have to be careful + + align:start position:0% +the energy but you have to be careful + + + align:start position:0% +the energy but you have to be careful +but + + align:start position:0% +but + + + align:start position:0% +but +you only have to be careful because of + + align:start position:0% +you only have to be careful because of + + + align:start position:0% +you only have to be careful because of +these out of block things and that's a + + align:start position:0% +these out of block things and that's a + + + align:start position:0% +these out of block things and that's a +subtle thing and most people can go + + align:start position:0% +subtle thing and most people can go + + + align:start position:0% +subtle thing and most people can go +through their life without worrying + + align:start position:0% +through their life without worrying + + + align:start position:0% +through their life without worrying +about that but there is a subtle + + align:start position:0% +about that but there is a subtle + + + align:start position:0% +about that but there is a subtle +business here and if you're a quantum + + align:start position:0% +business here and if you're a quantum + + + align:start position:0% +business here and if you're a quantum +chemist you need to know about that + + align:start position:0% +chemist you need to know about that + + + align:start position:0% +chemist you need to know about that +because you're going to be comparing + + align:start position:0% +because you're going to be comparing + + + align:start position:0% +because you're going to be comparing +what you calculate against experiment + + align:start position:0% +what you calculate against experiment + + + align:start position:0% +what you calculate against experiment +and it'll be apples and oranges but + + align:start position:0% +and it'll be apples and oranges but + + + align:start position:0% +and it'll be apples and oranges but +for experimental lists you don't really + + align:start position:0% +for experimental lists you don't really + + + align:start position:0% +for experimental lists you don't really +too worried about that too much so what + + align:start position:0% +too worried about that too much so what + + + align:start position:0% +too worried about that too much so what +we're going to start doing next lecture + + align:start position:0% +we're going to start doing next lecture + + + align:start position:0% +we're going to start doing next lecture +is start dealing with many electron + + align:start position:0% +is start dealing with many electron + + + align:start position:0% +is start dealing with many electron +atoms and what I want to do is I'm not + + align:start position:0% +atoms and what I want to do is I'm not + + + align:start position:0% +atoms and what I want to do is I'm not +going to teach you how to do quantum + + align:start position:0% +going to teach you how to do quantum + + + align:start position:0% +going to teach you how to do quantum +chemistry but I'm going to teach you how + + align:start position:0% +chemistry but I'm going to teach you how + + + align:start position:0% +chemistry but I'm going to teach you how +you can see the periodic structure the + + align:start position:0% +you can see the periodic structure the + + + align:start position:0% +you can see the periodic structure the +periodic table in the the control + + align:start position:0% +periodic table in the the control + + + align:start position:0% +periodic table in the the control +parameters that you use to build the + + align:start position:0% +parameters that you use to build the + + + align:start position:0% +parameters that you use to build the +energy levels of atoms out of and that + + align:start position:0% +energy levels of atoms out of and that + + + align:start position:0% +energy levels of atoms out of and that +then provides us with a rep a machinery + + align:start position:0% +then provides us with a rep a machinery + + + align:start position:0% +then provides us with a rep a machinery +that enables us to understand something + + align:start position:0% +that enables us to understand something + + + align:start position:0% +that enables us to understand something +about the energy levels of molecules and + + align:start position:0% +about the energy levels of molecules and + + + align:start position:0% +about the energy levels of molecules and +so it's when I started teaching this at + + align:start position:0% +so it's when I started teaching this at + + + align:start position:0% +so it's when I started teaching this at +MIT actually I I felt I have to show how + + align:start position:0% +MIT actually I I felt I have to show how + + + align:start position:0% +MIT actually I I felt I have to show how +the periodic table enters into the + + align:start position:0% +the periodic table enters into the + + + align:start position:0% +the periodic table enters into the +spectra of things and + + align:start position:0% +spectra of things and + + + align:start position:0% +spectra of things and +really a tremendous battle it's not so + + align:start position:0% +really a tremendous battle it's not so + + + align:start position:0% +really a tremendous battle it's not so +hard for atoms but it's really hard for + + align:start position:0% +hard for atoms but it's really hard for + + + align:start position:0% +hard for atoms but it's really hard for +molecules because you lose the spherical + + align:start position:0% +molecules because you lose the spherical + + + align:start position:0% +molecules because you lose the spherical +symmetry but there's still ways to make + + align:start position:0% +symmetry but there's still ways to make + + + align:start position:0% +symmetry but there's still ways to make +contact with periodicity and this is one + + align:start position:0% +contact with periodicity and this is one + + + align:start position:0% +contact with periodicity and this is one +of our central concepts shell structure + + align:start position:0% +of our central concepts shell structure + + + align:start position:0% +of our central concepts shell structure +and you know or but certain orbitals are + + align:start position:0% +and you know or but certain orbitals are + + + align:start position:0% +and you know or but certain orbitals are +small and shields well and other or + + align:start position:0% +small and shields well and other or + + + align:start position:0% +small and shields well and other or +below big and don't shield and all these + + align:start position:0% +below big and don't shield and all these + + + align:start position:0% +below big and don't shield and all these +concepts you know we learn as freshmen + + align:start position:0% +concepts you know we learn as freshmen + + + align:start position:0% +concepts you know we learn as freshmen +and it's + + align:start position:0% +and it's + + + align:start position:0% +and it's +certainly why I became a chemist and and + + align:start position:0% +certainly why I became a chemist and and + + + align:start position:0% +certainly why I became a chemist and and +so as a spectroscopy I want to do more + + align:start position:0% +so as a spectroscopy I want to do more + + + align:start position:0% +so as a spectroscopy I want to do more +than lip service to that and so we're + + align:start position:0% +than lip service to that and so we're + + + align:start position:0% +than lip service to that and so we're +going to go through some fairly + + align:start position:0% +going to go through some fairly + + + align:start position:0% +going to go through some fairly +elementary stuff on many electron atoms + + align:start position:0% +elementary stuff on many electron atoms + + + align:start position:0% +elementary stuff on many electron atoms +and then get into molecules and I think + + align:start position:0% +and then get into molecules and I think + + + align:start position:0% +and then get into molecules and I think +then it'll be a more traditional + + align:start position:0% +then it'll be a more traditional + + + align:start position:0% +then it'll be a more traditional +trajectory + + align:start position:0% + + + + align:start position:0% + +through the relevant spectroscopic + + align:start position:0% +through the relevant spectroscopic + + + align:start position:0% +through the relevant spectroscopic +theory and but + + align:start position:0% +theory and but + + + align:start position:0% +theory and but +i do love atoms and you you'll probably + + align:start position:0% +i do love atoms and you you'll probably + + + align:start position:0% +i do love atoms and you you'll probably +say enough Adams already okay see you + + align:start position:0% +say enough Adams already okay see you + + + align:start position:0% +say enough Adams already okay see you +Wednesday oh yeah the + + align:start position:0% +Wednesday oh yeah the + + + align:start position:0% +Wednesday oh yeah the +kind of business that you show there + + align:start position:0% +kind of business that you show there + + + align:start position:0% +kind of business that you show there +where the omega 1.is proximately is + + align:start position:0% +where the omega 1.is proximately is + + + align:start position:0% +where the omega 1.is proximately is +that classical an analog to classical + + align:start position:0% +that classical an analog to classical + + + align:start position:0% +that classical an analog to classical +references p.s letters that are + + align:start position:0% +references p.s letters that are + + + align:start position:0% +references p.s letters that are +oscillating your mobile yes so two + + align:start position:0% +oscillating your mobile yes so two + + + align:start position:0% +oscillating your mobile yes so two +questions first of all how close do they + + align:start position:0% +questions first of all how close do they + + + align:start position:0% +questions first of all how close do they +have to be before you start caring well + + align:start position:0% +have to be before you start caring well + + + align:start position:0% +have to be before you start caring well +in is there some other kind of resonance + + align:start position:0% +in is there some other kind of resonance + + + align:start position:0% +in is there some other kind of resonance +that also comes up that somehow + + align:start position:0% +that also comes up that somehow + + + align:start position:0% +that also comes up that somehow +inherently + + align:start position:0% +inherently + + + align:start position:0% +inherently +no or what do you mean when you call it + + align:start position:0% +no or what do you mean when you call it + + + align:start position:0% +no or what do you mean when you call it +a classical both you've been in your car + + align:start position:0% +a classical both you've been in your car + + + align:start position:0% +a classical both you've been in your car +and its wheels aren't quite aligned and + + align:start position:0% +and its wheels aren't quite aligned and + + + align:start position:0% +and its wheels aren't quite aligned and +you're going over some road that has + + align:start position:0% +you're going over some road that has + + + align:start position:0% +you're going over some road that has +periodic structure and at a certain + + align:start position:0% +periodic structure and at a certain + + + align:start position:0% +periodic structure and at a certain +velocity you discover you bitter slow to + + align:start position:0% +velocity you discover you bitter slow to + + + align:start position:0% +velocity you discover you bitter slow to +slow down or speed up and that's a + + align:start position:0% +slow down or speed up and that's a + + + align:start position:0% +slow down or speed up and that's a +resonance because there's a natural + + align:start position:0% +resonance because there's a natural + + + align:start position:0% +resonance because there's a natural +mechanical resonance in the car and + + align:start position:0% +mechanical resonance in the car and + + + align:start position:0% +mechanical resonance in the car and +you're you're you're perturbing your + + align:start position:0% +you're you're you're perturbing your + + + align:start position:0% +you're you're you're perturbing your +system at an integer multiple or sub + + align:start position:0% +system at an integer multiple or sub + + + align:start position:0% +system at an integer multiple or sub +multiple of that and it gets it's a + + align:start position:0% +multiple of that and it gets it's a + + + align:start position:0% +multiple of that and it gets it's a +starts absorbing energy and resonance is + + align:start position:0% +starts absorbing energy and resonance is + + + align:start position:0% +starts absorbing energy and resonance is +what leads to energy moving from one + + align:start position:0% +what leads to energy moving from one + + + align:start position:0% +what leads to energy moving from one +part of the molecule to another it's + + align:start position:0% +part of the molecule to another it's + + + align:start position:0% +part of the molecule to another it's +always resonance that controls most of + + align:start position:0% +always resonance that controls most of + + + align:start position:0% +always resonance that controls most of +the dynamics that we can understand now + + align:start position:0% +the dynamics that we can understand now + + + align:start position:0% +the dynamics that we can understand now +when is it big enough well the coupling + + align:start position:0% +when is it big enough well the coupling + + + align:start position:0% +when is it big enough well the coupling +terms grow as the + + align:start position:0% +terms grow as the + + + align:start position:0% +terms grow as the +quantum numbers go up they go up as the + + align:start position:0% +quantum numbers go up they go up as the + + + align:start position:0% +quantum numbers go up they go up as the +square root or the square root to + + align:start position:0% +square root or the square root to + + + align:start position:0% +square root or the square root to +certain power of the quantum numbers and + + align:start position:0% +certain power of the quantum numbers and + + + align:start position:0% +certain power of the quantum numbers and +the energy defect doesn't grow and so a + + align:start position:0% +the energy defect doesn't grow and so a + + + align:start position:0% +the energy defect doesn't grow and so a +resonance will generally make itself + + align:start position:0% +resonance will generally make itself + + + align:start position:0% +resonance will generally make itself +felt eventually as you go up in energy + + align:start position:0% +felt eventually as you go up in energy + + + align:start position:0% +felt eventually as you go up in energy +conversely + + align:start position:0% + + + + align:start position:0% + +if it happens it won't go away the + + align:start position:0% +if it happens it won't go away the + + + align:start position:0% +if it happens it won't go away the +there is a special situation where you + + align:start position:0% +there is a special situation where you + + + align:start position:0% +there is a special situation where you +can tune into resonance very early we're + + align:start position:0% +can tune into resonance very early we're + + + align:start position:0% +can tune into resonance very early we're +at a very sharp angle of attack on the + + align:start position:0% +at a very sharp angle of attack on the + + + align:start position:0% +at a very sharp angle of attack on the +energy levels and then you + + align:start position:0% +energy levels and then you + + + align:start position:0% +energy levels and then you +can detune from resonance because the + + align:start position:0% +can detune from resonance because the + + + align:start position:0% +can detune from resonance because the +levels move apart faster than the matrix + + align:start position:0% +levels move apart faster than the matrix + + + align:start position:0% +levels move apart faster than the matrix +elements can grow but that's very hard + + align:start position:0% +elements can grow but that's very hard + + + align:start position:0% +elements can grow but that's very hard +to cook up and so + + align:start position:0% +to cook up and so + + + align:start position:0% +to cook up and so +it's very typical that if there is a + + align:start position:0% +it's very typical that if there is a + + + align:start position:0% +it's very typical that if there is a +resonance it just gets worse or and + + align:start position:0% +resonance it just gets worse or and + + + align:start position:0% +resonance it just gets worse or and +Mercer but + + align:start position:0% +Mercer but + + + align:start position:0% +Mercer but +you know you know once you once you've + + align:start position:0% +you know you know once you once you've + + + align:start position:0% +you know you know once you once you've +solved the problem of the residents it + + align:start position:0% +solved the problem of the residents it + + + align:start position:0% +solved the problem of the residents it +doesn't matter because you're smarter + + align:start position:0% +doesn't matter because you're smarter + + + align:start position:0% +doesn't matter because you're smarter +than it and all it does is scale and so + + align:start position:0% +than it and all it does is scale and so + + + align:start position:0% +than it and all it does is scale and so +you know it scales in the number of + + align:start position:0% +you know it scales in the number of + + + align:start position:0% +you know it scales in the number of +resonance states and the strength of the + + align:start position:0% +resonance states and the strength of the + + + align:start position:0% +resonance states and the strength of the +resonance but everything has been + + align:start position:0% +resonance but everything has been + + + align:start position:0% +resonance but everything has been +determined from the first appearance you + + align:start position:0% +determined from the first appearance you + + + align:start position:0% +determined from the first appearance you +know what you need is the coupling term + + align:start position:0% +know what you need is the coupling term + + + align:start position:0% +know what you need is the coupling term +and the energy defect and once you know + + align:start position:0% +and the energy defect and once you know + + + align:start position:0% +and the energy defect and once you know +those it's it's all over for the + + align:start position:0% +those it's it's all over for the + + + align:start position:0% +those it's it's all over for the +molecules who is the first type of + + align:start position:0% +molecules who is the first type of + + + align:start position:0% +molecules who is the first type of +residence type in a very steep angle + + align:start position:0% +residence type in a very steep angle + + + align:start position:0% +residence type in a very steep angle +diagonally peers and energy is you call + + align:start position:0% +diagonally peers and energy is you call + + + align:start position:0% +diagonally peers and energy is you call +that accidental residence yes I would + + align:start position:0% +that accidental residence yes I would + + + align:start position:0% +that accidental residence yes I would +call it accidental in the other side is + + align:start position:0% +call it accidental in the other side is + + + align:start position:0% +call it accidental in the other side is +a because matica yes or global and + + align:start position:0% +a because matica yes or global and + + + align:start position:0% +a because matica yes or global and +it turns out that you + + align:start position:0% +it turns out that you + + + align:start position:0% +it turns out that you +can have a very high order resonance + + align:start position:0% +can have a very high order resonance + + + align:start position:0% +can have a very high order resonance +like you have 124 or something like that + + align:start position:0% +like you have 124 or something like that + + + align:start position:0% +like you have 124 or something like that +then the one doesn't scale the floor + + align:start position:0% +then the one doesn't scale the floor + + + align:start position:0% +then the one doesn't scale the floor +does scale but they can crash through + + align:start position:0% +does scale but they can crash through + + + align:start position:0% +does scale but they can crash through +each other really fast when it's a 222 + + align:start position:0% +each other really fast when it's a 222 + + + align:start position:0% +each other really fast when it's a 222 +it's really hard to to cook up a problem + + align:start position:0% +it's really hard to to cook up a problem + + + align:start position:0% +it's really hard to to cook up a problem +that dtunes from residents no matter + + align:start position:0% +that dtunes from residents no matter + + + align:start position:0% +that dtunes from residents no matter +what and I found the algebra that to do + + align:start position:0% +what and I found the algebra that to do + + + align:start position:0% +what and I found the algebra that to do +that but I chose the wrong one in the a + + align:start position:0% +that but I chose the wrong one in the a + + + align:start position:0% +that but I chose the wrong one in the a +privet there is going to be a paper on + + align:start position:0% +privet there is going to be a paper on + + + align:start position:0% +privet there is going to be a paper on +effective Hamiltonians which I will + + align:start position:0% +effective Hamiltonians which I will + + + align:start position:0% +effective Hamiltonians which I will +distribute to the class at some point + + align:start position:0% +distribute to the class at some point + + + align:start position:0% +distribute to the class at some point +which is sort of my magnum opus you know + + align:start position:0% +which is sort of my magnum opus you know + + + align:start position:0% +which is sort of my magnum opus you know +what I've been working on all my + + align:start position:0% +what I've been working on all my + + + align:start position:0% +what I've been working on all my +scientific career and so + + align:start position:0% +scientific career and so + + + align:start position:0% +scientific career and so +there will be something that I will + + align:start position:0% +there will be something that I will + + + align:start position:0% +there will be something that I will +share with you but that's neither here + + align:start position:0% +share with you but that's neither here + + + align:start position:0% +share with you but that's neither here +nor there right now so + + align:start position:0% + + + + align:start position:0% + +thank you \ No newline at end of file